hppa: Fix LO_SUM DLTIND14R address support in PRINT_OPERAND_ADDRESS
[official-gcc.git] / gcc / target.def
blobfdad7bbc93e2ad8aea30336d5cd4af67801e9c74
1 /* Target hook definitions.
2 Copyright (C) 2001-2024 Free Software Foundation, Inc.
4 This program is free software; you can redistribute it and/or modify it
5 under the terms of the GNU General Public License as published by the
6 Free Software Foundation; either version 3, or (at your option) any
7 later version.
9 This program is distributed in the hope that it will be useful,
10 but WITHOUT ANY WARRANTY; without even the implied warranty of
11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 GNU General Public License for more details.
14 You should have received a copy of the GNU General Public License
15 along with this program; see the file COPYING3. If not see
16 <http://www.gnu.org/licenses/>.
18 In other words, you are welcome to use, share and improve this program.
19 You are forbidden to forbid anyone else to use, share and improve
20 what you give them. Help stamp out software-hoarding! */
22 /* See target-hooks-macros.h for details of macros that should be
23 provided by the including file, and how to use them here. */
24 #include "target-hooks-macros.h"
26 #undef HOOK_TYPE
27 #define HOOK_TYPE "Target Hook"
29 HOOK_VECTOR (TARGET_INITIALIZER, gcc_target)
31 /* Functions that output assembler for the target. */
32 #define HOOK_PREFIX "TARGET_ASM_"
33 HOOK_VECTOR (TARGET_ASM_OUT, asm_out)
35 /* Opening and closing parentheses for asm expression grouping. */
36 DEFHOOKPOD
37 (open_paren,
38 "These target hooks are C string constants, describing the syntax in the\n\
39 assembler for grouping arithmetic expressions. If not overridden, they\n\
40 default to normal parentheses, which is correct for most assemblers.",
41 const char *, "(")
42 DEFHOOKPODX (close_paren, const char *, ")")
44 /* Assembler instructions for creating various kinds of integer object. */
45 DEFHOOKPOD
46 (byte_op,
47 "@deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_HI_OP\n\
48 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_PSI_OP\n\
49 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_SI_OP\n\
50 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_PDI_OP\n\
51 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_DI_OP\n\
52 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_PTI_OP\n\
53 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_TI_OP\n\
54 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_HI_OP\n\
55 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_PSI_OP\n\
56 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_SI_OP\n\
57 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_PDI_OP\n\
58 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_DI_OP\n\
59 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_PTI_OP\n\
60 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_TI_OP\n\
61 These hooks specify assembly directives for creating certain kinds\n\
62 of integer object. The @code{TARGET_ASM_BYTE_OP} directive creates a\n\
63 byte-sized object, the @code{TARGET_ASM_ALIGNED_HI_OP} one creates an\n\
64 aligned two-byte object, and so on. Any of the hooks may be\n\
65 @code{NULL}, indicating that no suitable directive is available.\n\
66 \n\
67 The compiler will print these strings at the start of a new line,\n\
68 followed immediately by the object's initial value. In most cases,\n\
69 the string should contain a tab, a pseudo-op, and then another tab.",
70 const char *, "\t.byte\t")
71 DEFHOOKPOD (aligned_op, "*", struct asm_int_op, TARGET_ASM_ALIGNED_INT_OP)
72 DEFHOOKPOD (unaligned_op, "*", struct asm_int_op, TARGET_ASM_UNALIGNED_INT_OP)
74 /* Try to output the assembler code for an integer object whose
75 value is given by X. SIZE is the size of the object in bytes and
76 ALIGNED_P indicates whether it is aligned. Return true if
77 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
78 and UNALIGNED_OP are NULL. */
79 DEFHOOK
80 (integer,
81 "The @code{assemble_integer} function uses this hook to output an\n\
82 integer object. @var{x} is the object's value, @var{size} is its size\n\
83 in bytes and @var{aligned_p} indicates whether it is aligned. The\n\
84 function should return @code{true} if it was able to output the\n\
85 object. If it returns false, @code{assemble_integer} will try to\n\
86 split the object into smaller parts.\n\
87 \n\
88 The default implementation of this hook will use the\n\
89 @code{TARGET_ASM_BYTE_OP} family of strings, returning @code{false}\n\
90 when the relevant string is @code{NULL}.",
91 /* Only handles cases for which BYTE_OP, ALIGNED_OP and UNALIGNED_OP are
92 NULL. */
93 bool, (rtx x, unsigned int size, int aligned_p),
94 default_assemble_integer)
96 /* Assembly strings required after the .cfi_startproc label. */
97 DEFHOOK
98 (post_cfi_startproc,
99 "This target hook is used to emit assembly strings required by the target\n\
100 after the .cfi_startproc directive. The first argument is the file stream to\n\
101 write the strings to and the second argument is the function\'s declaration. The\n\
102 expected use is to add more .cfi_* directives.\n\
104 The default is to not output any assembly strings.",
105 void, (FILE *, tree),
106 hook_void_FILEptr_tree)
108 /* Notify the backend that we have completed emitting the data for a
109 decl. */
110 DEFHOOK
111 (decl_end,
112 "Define this hook if the target assembler requires a special marker to\n\
113 terminate an initialized variable declaration.",
114 void, (void),
115 hook_void_void)
117 /* Output code that will globalize a label. */
118 DEFHOOK
119 (globalize_label,
120 "This target hook is a function to output to the stdio stream\n\
121 @var{stream} some commands that will make the label @var{name} global;\n\
122 that is, available for reference from other files.\n\
124 The default implementation relies on a proper definition of\n\
125 @code{GLOBAL_ASM_OP}.",
126 void, (FILE *stream, const char *name),
127 default_globalize_label)
129 /* Output code that will globalize a declaration. */
130 DEFHOOK
131 (globalize_decl_name,
132 "This target hook is a function to output to the stdio stream\n\
133 @var{stream} some commands that will make the name associated with @var{decl}\n\
134 global; that is, available for reference from other files.\n\
136 The default implementation uses the TARGET_ASM_GLOBALIZE_LABEL target hook.",
137 void, (FILE *stream, tree decl), default_globalize_decl_name)
139 /* Output code that will declare an external variable. */
140 DEFHOOK
141 (assemble_undefined_decl,
142 "This target hook is a function to output to the stdio stream\n\
143 @var{stream} some commands that will declare the name associated with\n\
144 @var{decl} which is not defined in the current translation unit. Most\n\
145 assemblers do not require anything to be output in this case.",
146 void, (FILE *stream, const char *name, const_tree decl),
147 hook_void_FILEptr_constcharptr_const_tree)
149 /* Output code that will emit a label for unwind info, if this
150 target requires such labels. Second argument is the decl the
151 unwind info is associated with, third is a boolean: true if
152 this is for exception handling, fourth is a boolean: true if
153 this is only a placeholder for an omitted FDE. */
154 DEFHOOK
155 (emit_unwind_label,
156 "This target hook emits a label at the beginning of each FDE@. It\n\
157 should be defined on targets where FDEs need special labels, and it\n\
158 should write the appropriate label, for the FDE associated with the\n\
159 function declaration @var{decl}, to the stdio stream @var{stream}.\n\
160 The third argument, @var{for_eh}, is a boolean: true if this is for an\n\
161 exception table. The fourth argument, @var{empty}, is a boolean:\n\
162 true if this is a placeholder label for an omitted FDE@.\n\
164 The default is that FDEs are not given nonlocal labels.",
165 void, (FILE *stream, tree decl, int for_eh, int empty),
166 default_emit_unwind_label)
168 /* Output code that will emit a label to divide up the exception table. */
169 DEFHOOK
170 (emit_except_table_label,
171 "This target hook emits a label at the beginning of the exception table.\n\
172 It should be defined on targets where it is desirable for the table\n\
173 to be broken up according to function.\n\
175 The default is that no label is emitted.",
176 void, (FILE *stream),
177 default_emit_except_table_label)
179 /* Emit a directive for setting the personality for the function. */
180 DEFHOOK
181 (emit_except_personality,
182 "If the target implements @code{TARGET_ASM_UNWIND_EMIT}, this hook may be\n\
183 used to emit a directive to install a personality hook into the unwind\n\
184 info. This hook should not be used if dwarf2 unwind info is used.",
185 void, (rtx personality),
186 NULL)
188 /* If necessary, modify personality and LSDA references to handle
189 indirection. This is used when the assembler supports CFI directives. */
190 DEFHOOK
191 (make_eh_symbol_indirect,
192 "If necessary, modify personality and LSDA references to handle indirection.\n\
193 The original symbol is in @code{origsymbol} and if @code{pubvis} is true\n\
194 the symbol is visible outside the TU.",
195 rtx, (rtx origsymbol, bool pubvis),
196 NULL)
198 /* Emit any directives required to unwind this instruction. */
199 DEFHOOK
200 (unwind_emit,
201 "This target hook emits assembly directives required to unwind the\n\
202 given instruction. This is only used when @code{TARGET_EXCEPT_UNWIND_INFO}\n\
203 returns @code{UI_TARGET}.",
204 void, (FILE *stream, rtx_insn *insn),
205 NULL)
207 DEFHOOKPOD
208 (unwind_emit_before_insn,
209 "True if the @code{TARGET_ASM_UNWIND_EMIT} hook should be called before\n\
210 the assembly for @var{insn} has been emitted, false if the hook should\n\
211 be called afterward.",
212 bool, true)
214 /* Return true if the target needs extra instructions to restore the current
215 frame address after a DW_CFA_restore_state opcode. */
216 DEFHOOK
217 (should_restore_cfa_state,
218 "For DWARF-based unwind frames, two CFI instructions provide for save and\n\
219 restore of register state. GCC maintains the current frame address (CFA)\n\
220 separately from the register bank but the unwinder in libgcc preserves this\n\
221 state along with the registers (and this is expected by the code that writes\n\
222 the unwind frames). This hook allows the target to specify that the CFA data\n\
223 is not saved/restored along with the registers by the target unwinder so that\n\
224 suitable additional instructions should be emitted to restore it.",
225 bool, (void),
226 hook_bool_void_false)
228 /* Generate an internal label.
229 For now this is just a wrapper for ASM_GENERATE_INTERNAL_LABEL. */
230 DEFHOOK_UNDOC
231 (generate_internal_label,
233 void, (char *buf, const char *prefix, unsigned long labelno),
234 default_generate_internal_label)
236 /* Output an internal label. */
237 DEFHOOK
238 (internal_label,
239 "A function to output to the stdio stream @var{stream} a label whose\n\
240 name is made from the string @var{prefix} and the number @var{labelno}.\n\
242 It is absolutely essential that these labels be distinct from the labels\n\
243 used for user-level functions and variables. Otherwise, certain programs\n\
244 will have name conflicts with internal labels.\n\
246 It is desirable to exclude internal labels from the symbol table of the\n\
247 object file. Most assemblers have a naming convention for labels that\n\
248 should be excluded; on many systems, the letter @samp{L} at the\n\
249 beginning of a label has this effect. You should find out what\n\
250 convention your system uses, and follow it.\n\
252 The default version of this function utilizes @code{ASM_GENERATE_INTERNAL_LABEL}.",
253 void, (FILE *stream, const char *prefix, unsigned long labelno),
254 default_internal_label)
256 /* Output label for the constant. */
257 DEFHOOK
258 (declare_constant_name,
259 "A target hook to output to the stdio stream @var{file} any text necessary\n\
260 for declaring the name @var{name} of a constant which is being defined. This\n\
261 target hook is responsible for outputting the label definition (perhaps using\n\
262 @code{assemble_label}). The argument @var{exp} is the value of the constant,\n\
263 and @var{size} is the size of the constant in bytes. The @var{name}\n\
264 will be an internal label.\n\
266 The default version of this target hook, define the @var{name} in the\n\
267 usual manner as a label (by means of @code{assemble_label}).\n\
269 You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in this target hook.",
270 void, (FILE *file, const char *name, const_tree expr, HOST_WIDE_INT size),
271 default_asm_declare_constant_name)
273 /* Emit a ttype table reference to a typeinfo object. */
274 DEFHOOK
275 (ttype,
276 "This hook is used to output a reference from a frame unwinding table to\n\
277 the type_info object identified by @var{sym}. It should return @code{true}\n\
278 if the reference was output. Returning @code{false} will cause the\n\
279 reference to be output using the normal Dwarf2 routines.",
280 bool, (rtx sym),
281 hook_bool_rtx_false)
283 /* Emit an assembler directive to set visibility for the symbol
284 associated with the tree decl. */
285 DEFHOOK
286 (assemble_visibility,
287 "This target hook is a function to output to @var{asm_out_file} some\n\
288 commands that will make the symbol(s) associated with @var{decl} have\n\
289 hidden, protected or internal visibility as specified by @var{visibility}.",
290 void, (tree decl, int visibility),
291 default_assemble_visibility)
293 DEFHOOK
294 (print_patchable_function_entry,
295 "Generate a patchable area at the function start, consisting of\n\
296 @var{patch_area_size} NOP instructions. If the target supports named\n\
297 sections and if @var{record_p} is true, insert a pointer to the current\n\
298 location in the table of patchable functions. The default implementation\n\
299 of the hook places the table of pointers in the special section named\n\
300 @code{__patchable_function_entries}.",
301 void, (FILE *file, unsigned HOST_WIDE_INT patch_area_size, bool record_p),
302 default_print_patchable_function_entry)
304 /* Output the assembler code for entry to a function. */
305 DEFHOOK
306 (function_prologue,
307 "If defined, a function that outputs the assembler code for entry to a\n\
308 function. The prologue is responsible for setting up the stack frame,\n\
309 initializing the frame pointer register, saving registers that must be\n\
310 saved, and allocating @var{size} additional bytes of storage for the\n\
311 local variables. @var{file} is a stdio stream to which the assembler\n\
312 code should be output.\n\
314 The label for the beginning of the function need not be output by this\n\
315 macro. That has already been done when the macro is run.\n\
317 @findex regs_ever_live\n\
318 To determine which registers to save, the macro can refer to the array\n\
319 @code{regs_ever_live}: element @var{r} is nonzero if hard register\n\
320 @var{r} is used anywhere within the function. This implies the function\n\
321 prologue should save register @var{r}, provided it is not one of the\n\
322 call-used registers. (@code{TARGET_ASM_FUNCTION_EPILOGUE} must likewise use\n\
323 @code{regs_ever_live}.)\n\
325 On machines that have ``register windows'', the function entry code does\n\
326 not save on the stack the registers that are in the windows, even if\n\
327 they are supposed to be preserved by function calls; instead it takes\n\
328 appropriate steps to ``push'' the register stack, if any non-call-used\n\
329 registers are used in the function.\n\
331 @findex frame_pointer_needed\n\
332 On machines where functions may or may not have frame-pointers, the\n\
333 function entry code must vary accordingly; it must set up the frame\n\
334 pointer if one is wanted, and not otherwise. To determine whether a\n\
335 frame pointer is in wanted, the macro can refer to the variable\n\
336 @code{frame_pointer_needed}. The variable's value will be 1 at run\n\
337 time in a function that needs a frame pointer. @xref{Elimination}.\n\
339 The function entry code is responsible for allocating any stack space\n\
340 required for the function. This stack space consists of the regions\n\
341 listed below. In most cases, these regions are allocated in the\n\
342 order listed, with the last listed region closest to the top of the\n\
343 stack (the lowest address if @code{STACK_GROWS_DOWNWARD} is defined, and\n\
344 the highest address if it is not defined). You can use a different order\n\
345 for a machine if doing so is more convenient or required for\n\
346 compatibility reasons. Except in cases where required by standard\n\
347 or by a debugger, there is no reason why the stack layout used by GCC\n\
348 need agree with that used by other compilers for a machine.",
349 void, (FILE *file),
350 default_function_pro_epilogue)
352 /* Output the assembler code for end of prologue. */
353 DEFHOOK
354 (function_end_prologue,
355 "If defined, a function that outputs assembler code at the end of a\n\
356 prologue. This should be used when the function prologue is being\n\
357 emitted as RTL, and you have some extra assembler that needs to be\n\
358 emitted. @xref{prologue instruction pattern}.",
359 void, (FILE *file),
360 no_asm_to_stream)
362 /* Output the assembler code for start of epilogue. */
363 DEFHOOK
364 (function_begin_epilogue,
365 "If defined, a function that outputs assembler code at the start of an\n\
366 epilogue. This should be used when the function epilogue is being\n\
367 emitted as RTL, and you have some extra assembler that needs to be\n\
368 emitted. @xref{epilogue instruction pattern}.",
369 void, (FILE *file),
370 no_asm_to_stream)
372 /* Output the assembler code for function exit. */
373 DEFHOOK
374 (function_epilogue,
375 "If defined, a function that outputs the assembler code for exit from a\n\
376 function. The epilogue is responsible for restoring the saved\n\
377 registers and stack pointer to their values when the function was\n\
378 called, and returning control to the caller. This macro takes the\n\
379 same argument as the macro @code{TARGET_ASM_FUNCTION_PROLOGUE}, and the\n\
380 registers to restore are determined from @code{regs_ever_live} and\n\
381 @code{CALL_USED_REGISTERS} in the same way.\n\
383 On some machines, there is a single instruction that does all the work\n\
384 of returning from the function. On these machines, give that\n\
385 instruction the name @samp{return} and do not define the macro\n\
386 @code{TARGET_ASM_FUNCTION_EPILOGUE} at all.\n\
388 Do not define a pattern named @samp{return} if you want the\n\
389 @code{TARGET_ASM_FUNCTION_EPILOGUE} to be used. If you want the target\n\
390 switches to control whether return instructions or epilogues are used,\n\
391 define a @samp{return} pattern with a validity condition that tests the\n\
392 target switches appropriately. If the @samp{return} pattern's validity\n\
393 condition is false, epilogues will be used.\n\
395 On machines where functions may or may not have frame-pointers, the\n\
396 function exit code must vary accordingly. Sometimes the code for these\n\
397 two cases is completely different. To determine whether a frame pointer\n\
398 is wanted, the macro can refer to the variable\n\
399 @code{frame_pointer_needed}. The variable's value will be 1 when compiling\n\
400 a function that needs a frame pointer.\n\
402 Normally, @code{TARGET_ASM_FUNCTION_PROLOGUE} and\n\
403 @code{TARGET_ASM_FUNCTION_EPILOGUE} must treat leaf functions specially.\n\
404 The C variable @code{current_function_is_leaf} is nonzero for such a\n\
405 function. @xref{Leaf Functions}.\n\
407 On some machines, some functions pop their arguments on exit while\n\
408 others leave that for the caller to do. For example, the 68020 when\n\
409 given @option{-mrtd} pops arguments in functions that take a fixed\n\
410 number of arguments.\n\
412 @findex pops_args\n\
413 @findex crtl->args.pops_args\n\
414 Your definition of the macro @code{RETURN_POPS_ARGS} decides which\n\
415 functions pop their own arguments. @code{TARGET_ASM_FUNCTION_EPILOGUE}\n\
416 needs to know what was decided. The number of bytes of the current\n\
417 function's arguments that this function should pop is available in\n\
418 @code{crtl->args.pops_args}. @xref{Scalar Return}.",
419 void, (FILE *file),
420 default_function_pro_epilogue)
422 /* Initialize target-specific sections. */
423 DEFHOOK
424 (init_sections,
425 "Define this hook if you need to do something special to set up the\n\
426 @file{varasm.cc} sections, or if your target has some special sections\n\
427 of its own that you need to create.\n\
429 GCC calls this hook after processing the command line, but before writing\n\
430 any assembly code, and before calling any of the section-returning hooks\n\
431 described below.",
432 void, (void),
433 hook_void_void)
435 /* Tell assembler to change to section NAME with attributes FLAGS.
436 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
437 which this section is associated. */
438 DEFHOOK
439 (named_section,
440 "Output assembly directives to switch to section @var{name}. The section\n\
441 should have attributes as specified by @var{flags}, which is a bit mask\n\
442 of the @code{SECTION_*} flags defined in @file{output.h}. If @var{decl}\n\
443 is non-NULL, it is the @code{VAR_DECL} or @code{FUNCTION_DECL} with which\n\
444 this section is associated.",
445 void, (const char *name, unsigned int flags, tree decl),
446 default_no_named_section)
448 /* Tell assembler what section attributes to assign this elf section
449 declaration, using their numerical value. */
450 DEFHOOK
451 (elf_flags_numeric,
452 "This hook can be used to encode ELF section flags for which no letter\n\
453 code has been defined in the assembler. It is called by\n\
454 @code{default_asm_named_section} whenever the section flags need to be\n\
455 emitted in the assembler output. If the hook returns true, then the\n\
456 numerical value for ELF section flags should be calculated from\n\
457 @var{flags} and saved in @var{*num}; the value is printed out instead of the\n\
458 normal sequence of letter codes. If the hook is not defined, or if it\n\
459 returns false, then @var{num} is ignored and the traditional letter sequence\n\
460 is emitted.",
461 bool, (unsigned int flags, unsigned int *num),
462 hook_bool_uint_uintp_false)
464 /* Return preferred text (sub)section for function DECL.
465 Main purpose of this function is to separate cold, normal and hot
466 functions. STARTUP is true when function is known to be used only
467 at startup (from static constructors or it is main()).
468 EXIT is true when function is known to be used only at exit
469 (from static destructors).
470 Return NULL if function should go to default text section. */
471 DEFHOOK
472 (function_section,
473 "Return preferred text (sub)section for function @var{decl}.\n\
474 Main purpose of this function is to separate cold, normal and hot\n\
475 functions. @var{startup} is true when function is known to be used only\n\
476 at startup (from static constructors or it is @code{main()}).\n\
477 @var{exit} is true when function is known to be used only at exit\n\
478 (from static destructors).\n\
479 Return NULL if function should go to default text section.",
480 section *, (tree decl, enum node_frequency freq, bool startup, bool exit),
481 default_function_section)
483 /* Output the assembler code for function exit. */
484 DEFHOOK
485 (function_switched_text_sections,
486 "Used by the target to emit any assembler directives or additional\n\
487 labels needed when a function is partitioned between different\n\
488 sections. Output should be written to @var{file}. The function\n\
489 decl is available as @var{decl} and the new section is `cold' if\n\
490 @var{new_is_cold} is @code{true}.",
491 void, (FILE *file, tree decl, bool new_is_cold),
492 default_function_switched_text_sections)
494 /* Return a mask describing how relocations should be treated when
495 selecting sections. Bit 1 should be set if global relocations
496 should be placed in a read-write section; bit 0 should be set if
497 local relocations should be placed in a read-write section. */
498 DEFHOOK
499 (reloc_rw_mask,
500 "Return a mask describing how relocations should be treated when\n\
501 selecting sections. Bit 1 should be set if global relocations\n\
502 should be placed in a read-write section; bit 0 should be set if\n\
503 local relocations should be placed in a read-write section.\n\
505 The default version of this function returns 3 when @option{-fpic}\n\
506 is in effect, and 0 otherwise. The hook is typically redefined\n\
507 when the target cannot support (some kinds of) dynamic relocations\n\
508 in read-only sections even in executables.",
509 int, (void),
510 default_reloc_rw_mask)
512 /* Return a flag for either generating ADDR_DIF_VEC table
513 or ADDR_VEC table for jumps in case of -fPIC/-fPIE. */
514 DEFHOOK
515 (generate_pic_addr_diff_vec,
516 "Return true to generate ADDR_DIF_VEC table\n\
517 or false to generate ADDR_VEC table for jumps in case of -fPIC.\n\
519 The default version of this function returns true if flag_pic\n\
520 equals true and false otherwise",
521 bool, (void),
522 default_generate_pic_addr_diff_vec)
524 /* Return a section for EXP. It may be a DECL or a constant. RELOC
525 is nonzero if runtime relocations must be applied; bit 1 will be
526 set if the runtime relocations require non-local name resolution.
527 ALIGN is the required alignment of the data. */
528 DEFHOOK
529 (select_section,
530 "Return the section into which @var{exp} should be placed. You can\n\
531 assume that @var{exp} is either a @code{VAR_DECL} node or a constant of\n\
532 some sort. @var{reloc} indicates whether the initial value of @var{exp}\n\
533 requires link-time relocations. Bit 0 is set when variable contains\n\
534 local relocations only, while bit 1 is set for global relocations.\n\
535 @var{align} is the constant alignment in bits.\n\
537 The default version of this function takes care of putting read-only\n\
538 variables in @code{readonly_data_section}.\n\
540 See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}.",
541 section *, (tree exp, int reloc, unsigned HOST_WIDE_INT align),
542 default_select_section)
544 /* Return a section for X. MODE is X's mode and ALIGN is its
545 alignment in bits. */
546 DEFHOOK
547 (select_rtx_section,
548 "Return the section into which a constant @var{x}, of mode @var{mode},\n\
549 should be placed. You can assume that @var{x} is some kind of\n\
550 constant in RTL@. The argument @var{mode} is redundant except in the\n\
551 case of a @code{const_int} rtx. @var{align} is the constant alignment\n\
552 in bits.\n\
554 The default version of this function takes care of putting symbolic\n\
555 constants in @code{flag_pic} mode in @code{data_section} and everything\n\
556 else in @code{readonly_data_section}.",
557 section *, (machine_mode mode, rtx x, unsigned HOST_WIDE_INT align),
558 default_select_rtx_section)
560 /* Select a unique section name for DECL. RELOC is the same as
561 for SELECT_SECTION. */
562 DEFHOOK
563 (unique_section,
564 "Build up a unique section name, expressed as a @code{STRING_CST} node,\n\
565 and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.\n\
566 As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether\n\
567 the initial value of @var{exp} requires link-time relocations.\n\
569 The default version of this function appends the symbol name to the\n\
570 ELF section name that would normally be used for the symbol. For\n\
571 example, the function @code{foo} would be placed in @code{.text.foo}.\n\
572 Whatever the actual target object format, this is often good enough.",
573 void, (tree decl, int reloc),
574 default_unique_section)
576 /* Return the readonly data or relocated readonly data section
577 associated with function DECL. */
578 DEFHOOK
579 (function_rodata_section,
580 "Return the readonly data or reloc readonly data section associated with\n\
581 @samp{DECL_SECTION_NAME (@var{decl})}. @var{relocatable} selects the latter\n\
582 over the former.\n\
583 The default version of this function selects @code{.gnu.linkonce.r.name} if\n\
584 the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name}\n\
585 or @code{.data.rel.ro.name} if function is in @code{.text.name}, and\n\
586 the normal readonly-data or reloc readonly data section otherwise.",
587 section *, (tree decl, bool relocatable),
588 default_function_rodata_section)
590 /* Nonnull if the target wants to override the default ".rodata" prefix
591 for mergeable data sections. */
592 DEFHOOKPOD
593 (mergeable_rodata_prefix,
594 "Usually, the compiler uses the prefix @code{\".rodata\"} to construct\n\
595 section names for mergeable constant data. Define this macro to override\n\
596 the string if a different section name should be used.",
597 const char *, ".rodata")
599 /* Return the section to be used for transactional memory clone tables. */
600 DEFHOOK
601 (tm_clone_table_section,
602 "Return the section that should be used for transactional memory clone\n\
603 tables.",
604 section *, (void), default_clone_table_section)
606 /* Output a constructor for a symbol with a given priority. */
607 DEFHOOK
608 (constructor,
609 "If defined, a function that outputs assembler code to arrange to call\n\
610 the function referenced by @var{symbol} at initialization time.\n\
612 Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking\n\
613 no arguments and with no return value. If the target supports initialization\n\
614 priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY};\n\
615 otherwise it must be @code{DEFAULT_INIT_PRIORITY}.\n\
617 If this macro is not defined by the target, a suitable default will\n\
618 be chosen if (1) the target supports arbitrary section names, (2) the\n\
619 target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2}\n\
620 is not defined.",
621 void, (rtx symbol, int priority), NULL)
623 /* Output a destructor for a symbol with a given priority. */
624 DEFHOOK
625 (destructor,
626 "This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination\n\
627 functions rather than initialization functions.",
628 void, (rtx symbol, int priority), NULL)
630 /* Output the assembler code for a thunk function. THUNK_DECL is the
631 declaration for the thunk function itself, FUNCTION is the decl for
632 the target function. DELTA is an immediate constant offset to be
633 added to THIS. If VCALL_OFFSET is nonzero, the word at
634 *(*this + vcall_offset) should be added to THIS. */
635 DEFHOOK
636 (output_mi_thunk,
637 "A function that outputs the assembler code for a thunk\n\
638 function, used to implement C++ virtual function calls with multiple\n\
639 inheritance. The thunk acts as a wrapper around a virtual function,\n\
640 adjusting the implicit object parameter before handing control off to\n\
641 the real function.\n\
643 First, emit code to add the integer @var{delta} to the location that\n\
644 contains the incoming first argument. Assume that this argument\n\
645 contains a pointer, and is the one used to pass the @code{this} pointer\n\
646 in C++. This is the incoming argument @emph{before} the function prologue,\n\
647 e.g.@: @samp{%o0} on a sparc. The addition must preserve the values of\n\
648 all other incoming arguments.\n\
650 Then, if @var{vcall_offset} is nonzero, an additional adjustment should be\n\
651 made after adding @code{delta}. In particular, if @var{p} is the\n\
652 adjusted pointer, the following adjustment should be made:\n\
654 @smallexample\n\
655 p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]\n\
656 @end smallexample\n\
658 After the additions, emit code to jump to @var{function}, which is a\n\
659 @code{FUNCTION_DECL}. This is a direct pure jump, not a call, and does\n\
660 not touch the return address. Hence returning from @var{FUNCTION} will\n\
661 return to whoever called the current @samp{thunk}.\n\
663 The effect must be as if @var{function} had been called directly with\n\
664 the adjusted first argument. This macro is responsible for emitting all\n\
665 of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE}\n\
666 and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked.\n\
668 The @var{thunk_fndecl} is redundant. (@var{delta} and @var{function}\n\
669 have already been extracted from it.) It might possibly be useful on\n\
670 some targets, but probably not.\n\
672 If you do not define this macro, the target-independent code in the C++\n\
673 front end will generate a less efficient heavyweight thunk that calls\n\
674 @var{function} instead of jumping to it. The generic approach does\n\
675 not support varargs.",
676 void, (FILE *file, tree thunk_fndecl, HOST_WIDE_INT delta,
677 HOST_WIDE_INT vcall_offset, tree function),
678 NULL)
680 /* Determine whether output_mi_thunk would succeed. */
681 /* ??? Ideally, this hook would not exist, and success or failure
682 would be returned from output_mi_thunk directly. But there's
683 too much undo-able setup involved in invoking output_mi_thunk.
684 Could be fixed by making output_mi_thunk emit rtl instead of
685 text to the output file. */
686 DEFHOOK
687 (can_output_mi_thunk,
688 "A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able\n\
689 to output the assembler code for the thunk function specified by the\n\
690 arguments it is passed, and false otherwise. In the latter case, the\n\
691 generic approach will be used by the C++ front end, with the limitations\n\
692 previously exposed.",
693 bool, (const_tree thunk_fndecl, HOST_WIDE_INT delta,
694 HOST_WIDE_INT vcall_offset, const_tree function),
695 hook_bool_const_tree_hwi_hwi_const_tree_false)
697 /* Output any boilerplate text needed at the beginning of a
698 translation unit. */
699 DEFHOOK
700 (file_start,
701 "Output to @code{asm_out_file} any text which the assembler expects to\n\
702 find at the beginning of a file. The default behavior is controlled\n\
703 by two flags, documented below. Unless your target's assembler is\n\
704 quite unusual, if you override the default, you should call\n\
705 @code{default_file_start} at some point in your target hook. This\n\
706 lets other target files rely on these variables.",
707 void, (void),
708 default_file_start)
710 /* Output any boilerplate text needed at the end of a translation unit. */
711 DEFHOOK
712 (file_end,
713 "Output to @code{asm_out_file} any text which the assembler expects\n\
714 to find at the end of a file. The default is to output nothing.",
715 void, (void),
716 hook_void_void)
718 /* Output any boilerplate text needed at the beginning of an
719 LTO output stream. */
720 DEFHOOK
721 (lto_start,
722 "Output to @code{asm_out_file} any text which the assembler expects\n\
723 to find at the start of an LTO section. The default is to output\n\
724 nothing.",
725 void, (void),
726 hook_void_void)
728 /* Output any boilerplate text needed at the end of an
729 LTO output stream. */
730 DEFHOOK
731 (lto_end,
732 "Output to @code{asm_out_file} any text which the assembler expects\n\
733 to find at the end of an LTO section. The default is to output\n\
734 nothing.",
735 void, (void),
736 hook_void_void)
738 /* Output any boilerplace text needed at the end of a
739 translation unit before debug and unwind info is emitted. */
740 DEFHOOK
741 (code_end,
742 "Output to @code{asm_out_file} any text which is needed before emitting\n\
743 unwind info and debug info at the end of a file. Some targets emit\n\
744 here PIC setup thunks that cannot be emitted at the end of file,\n\
745 because they couldn't have unwind info then. The default is to output\n\
746 nothing.",
747 void, (void),
748 hook_void_void)
750 /* Output an assembler pseudo-op to declare a library function name
751 external. */
752 DEFHOOK
753 (external_libcall,
754 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
755 pseudo-op to declare a library function name external. The name of the\n\
756 library function is given by @var{symref}, which is a @code{symbol_ref}.",
757 void, (rtx symref),
758 default_external_libcall)
760 /* Output an assembler directive to mark decl live. This instructs
761 linker to not dead code strip this symbol. */
762 DEFHOOK
763 (mark_decl_preserved,
764 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
765 directive to annotate @var{symbol} as used. The Darwin target uses the\n\
766 .no_dead_code_strip directive.",
767 void, (const char *symbol),
768 hook_void_constcharptr)
770 /* Output a record of the command line switches that have been passed. */
771 DEFHOOK
772 (record_gcc_switches,
773 "Provides the target with the ability to record the gcc command line\n\
774 switches provided as argument.\n\
776 By default this hook is set to NULL, but an example implementation is\n\
777 provided for ELF based targets. Called @var{elf_record_gcc_switches},\n\
778 it records the switches as ASCII text inside a new, string mergeable\n\
779 section in the assembler output file. The name of the new section is\n\
780 provided by the @code{TARGET_ASM_RECORD_GCC_SWITCHES_SECTION} target\n\
781 hook.",
782 void, (const char *),
783 NULL)
785 /* The name of the section that the example ELF implementation of
786 record_gcc_switches will use to store the information. Target
787 specific versions of record_gcc_switches may or may not use
788 this information. */
789 DEFHOOKPOD
790 (record_gcc_switches_section,
791 "This is the name of the section that will be created by the example\n\
792 ELF implementation of the @code{TARGET_ASM_RECORD_GCC_SWITCHES} target\n\
793 hook.",
794 const char *, ".GCC.command.line")
796 /* Output the definition of a section anchor. */
797 DEFHOOK
798 (output_anchor,
799 "Write the assembly code to define section anchor @var{x}, which is a\n\
800 @code{SYMBOL_REF} for which @samp{SYMBOL_REF_ANCHOR_P (@var{x})} is true.\n\
801 The hook is called with the assembly output position set to the beginning\n\
802 of @code{SYMBOL_REF_BLOCK (@var{x})}.\n\
804 If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses\n\
805 it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}.\n\
806 If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition\n\
807 is @code{NULL}, which disables the use of section anchors altogether.",
808 void, (rtx x),
809 default_asm_output_anchor)
811 DEFHOOK
812 (output_ident,
813 "Output a string based on @var{name}, suitable for the @samp{#ident}\n\
814 directive, or the equivalent directive or pragma in non-C-family languages.\n\
815 If this hook is not defined, nothing is output for the @samp{#ident}\n\
816 directive.",
817 void, (const char *name),
818 hook_void_constcharptr)
820 /* Output a DTP-relative reference to a TLS symbol. */
821 DEFHOOK
822 (output_dwarf_dtprel,
823 "If defined, this target hook is a function which outputs a DTP-relative\n\
824 reference to the given TLS symbol of the specified size.",
825 void, (FILE *file, int size, rtx x),
826 NULL)
828 /* Some target machines need to postscan each insn after it is output. */
829 DEFHOOK
830 (final_postscan_insn,
831 "If defined, this target hook is a function which is executed just after the\n\
832 output of assembler code for @var{insn}, to change the mode of the assembler\n\
833 if necessary.\n\
835 Here the argument @var{opvec} is the vector containing the operands\n\
836 extracted from @var{insn}, and @var{noperands} is the number of\n\
837 elements of the vector which contain meaningful data for this insn.\n\
838 The contents of this vector are what was used to convert the insn\n\
839 template into assembler code, so you can change the assembler mode\n\
840 by checking the contents of the vector.",
841 void, (FILE *file, rtx_insn *insn, rtx *opvec, int noperands),
842 NULL)
844 /* Emit the trampoline template. This hook may be NULL. */
845 DEFHOOK
846 (trampoline_template,
847 "This hook is called by @code{assemble_trampoline_template} to output,\n\
848 on the stream @var{f}, assembler code for a block of data that contains\n\
849 the constant parts of a trampoline. This code should not include a\n\
850 label---the label is taken care of automatically.\n\
852 If you do not define this hook, it means no template is needed\n\
853 for the target. Do not define this hook on systems where the block move\n\
854 code to copy the trampoline into place would be larger than the code\n\
855 to generate it on the spot.",
856 void, (FILE *f),
857 NULL)
859 DEFHOOK
860 (output_source_filename,
861 "Output DWARF debugging information which indicates that filename\n\
862 @var{name} is the current source file to the stdio stream @var{file}.\n\
864 This target hook need not be defined if the standard form of output\n\
865 for the file format in use is appropriate.",
866 void ,(FILE *file, const char *name),
867 default_asm_output_source_filename)
869 DEFHOOK
870 (output_addr_const_extra,
871 "A target hook to recognize @var{rtx} patterns that @code{output_addr_const}\n\
872 can't deal with, and output assembly code to @var{file} corresponding to\n\
873 the pattern @var{x}. This may be used to allow machine-dependent\n\
874 @code{UNSPEC}s to appear within constants.\n\
876 If target hook fails to recognize a pattern, it must return @code{false},\n\
877 so that a standard error message is printed. If it prints an error message\n\
878 itself, by calling, for example, @code{output_operand_lossage}, it may just\n\
879 return @code{true}.",
880 bool, (FILE *file, rtx x),
881 hook_bool_FILEptr_rtx_false)
883 /* ??? The TARGET_PRINT_OPERAND* hooks are part of the asm_out struct,
884 even though that is not reflected in the macro name to override their
885 initializers. */
886 #undef HOOK_PREFIX
887 #define HOOK_PREFIX "TARGET_"
889 /* Emit a machine-specific insn operand. */
890 /* ??? tm.texi only documents the old macro PRINT_OPERAND,
891 not this hook, and uses a different name for the argument FILE. */
892 DEFHOOK_UNDOC
893 (print_operand,
895 void, (FILE *file, rtx x, int code),
896 default_print_operand)
898 /* Emit a machine-specific memory address. */
899 /* ??? tm.texi only documents the old macro PRINT_OPERAND_ADDRESS,
900 not this hook, and uses different argument names. */
901 DEFHOOK_UNDOC
902 (print_operand_address,
904 void, (FILE *file, machine_mode mode, rtx addr),
905 default_print_operand_address)
907 /* Determine whether CODE is a valid punctuation character for the
908 `print_operand' hook. */
909 /* ??? tm.texi only documents the old macro PRINT_OPERAND_PUNCT_VALID_P,
910 not this hook. */
911 DEFHOOK_UNDOC
912 (print_operand_punct_valid_p,
914 bool ,(unsigned char code),
915 default_print_operand_punct_valid_p)
917 /* Given a symbol name, perform same mangling as assemble_name and
918 ASM_OUTPUT_LABELREF, returning result as an IDENTIFIER_NODE. */
919 DEFHOOK
920 (mangle_assembler_name,
921 "Given a symbol @var{name}, perform same mangling as @code{varasm.cc}'s\n\
922 @code{assemble_name}, but in memory rather than to a file stream, returning\n\
923 result as an @code{IDENTIFIER_NODE}. Required for correct LTO symtabs. The\n\
924 default implementation calls the @code{TARGET_STRIP_NAME_ENCODING} hook and\n\
925 then prepends the @code{USER_LABEL_PREFIX}, if any.",
926 tree, (const char *name),
927 default_mangle_assembler_name)
929 HOOK_VECTOR_END (asm_out)
931 /* Functions relating to instruction scheduling. All of these
932 default to null pointers, which haifa-sched.cc looks for and handles. */
933 #undef HOOK_PREFIX
934 #define HOOK_PREFIX "TARGET_SCHED_"
935 HOOK_VECTOR (TARGET_SCHED, sched)
937 /* Given the current cost, COST, of an insn, INSN, calculate and
938 return a new cost based on its relationship to DEP_INSN through
939 the dependence LINK. The default is to make no adjustment. */
940 DEFHOOK
941 (adjust_cost,
942 "This function corrects the value of @var{cost} based on the\n\
943 relationship between @var{insn} and @var{dep_insn} through a\n\
944 dependence of type dep_type, and strength @var{dw}. It should return the new\n\
945 value. The default is to make no adjustment to @var{cost}. This can be\n\
946 used for example to specify to the scheduler using the traditional pipeline\n\
947 description that an output- or anti-dependence does not incur the same cost\n\
948 as a data-dependence. If the scheduler using the automaton based pipeline\n\
949 description, the cost of anti-dependence is zero and the cost of\n\
950 output-dependence is maximum of one and the difference of latency\n\
951 times of the first and the second insns. If these values are not\n\
952 acceptable, you could use the hook to modify them too. See also\n\
953 @pxref{Processor pipeline description}.",
954 int, (rtx_insn *insn, int dep_type1, rtx_insn *dep_insn, int cost,
955 unsigned int dw),
956 NULL)
958 /* Adjust the priority of an insn as you see fit. Returns the new priority. */
959 DEFHOOK
960 (adjust_priority,
961 "This hook adjusts the integer scheduling priority @var{priority} of\n\
962 @var{insn}. It should return the new priority. Increase the priority to\n\
963 execute @var{insn} earlier, reduce the priority to execute @var{insn}\n\
964 later. Do not define this hook if you do not need to adjust the\n\
965 scheduling priorities of insns.",
966 int, (rtx_insn *insn, int priority), NULL)
968 /* Function which returns the maximum number of insns that can be
969 scheduled in the same machine cycle. This must be constant
970 over an entire compilation. The default is 1. */
971 DEFHOOK
972 (issue_rate,
973 "This hook returns the maximum number of instructions that can ever\n\
974 issue at the same time on the target machine. The default is one.\n\
975 Although the insn scheduler can define itself the possibility of issue\n\
976 an insn on the same cycle, the value can serve as an additional\n\
977 constraint to issue insns on the same simulated processor cycle (see\n\
978 hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).\n\
979 This value must be constant over the entire compilation. If you need\n\
980 it to vary depending on what the instructions are, you must use\n\
981 @samp{TARGET_SCHED_VARIABLE_ISSUE}.",
982 int, (void), NULL)
984 /* Calculate how much this insn affects how many more insns we
985 can emit this cycle. Default is they all cost the same. */
986 DEFHOOK
987 (variable_issue,
988 "This hook is executed by the scheduler after it has scheduled an insn\n\
989 from the ready list. It should return the number of insns which can\n\
990 still be issued in the current cycle. The default is\n\
991 @samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and\n\
992 @code{USE}, which normally are not counted against the issue rate.\n\
993 You should define this hook if some insns take more machine resources\n\
994 than others, so that fewer insns can follow them in the same cycle.\n\
995 @var{file} is either a null pointer, or a stdio stream to write any\n\
996 debug output to. @var{verbose} is the verbose level provided by\n\
997 @option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that\n\
998 was scheduled.",
999 int, (FILE *file, int verbose, rtx_insn *insn, int more), NULL)
1001 /* Initialize machine-dependent scheduling code. */
1002 DEFHOOK
1003 (init,
1004 "This hook is executed by the scheduler at the beginning of each block of\n\
1005 instructions that are to be scheduled. @var{file} is either a null\n\
1006 pointer, or a stdio stream to write any debug output to. @var{verbose}\n\
1007 is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1008 @var{max_ready} is the maximum number of insns in the current scheduling\n\
1009 region that can be live at the same time. This can be used to allocate\n\
1010 scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}.",
1011 void, (FILE *file, int verbose, int max_ready), NULL)
1013 /* Finalize machine-dependent scheduling code. */
1014 DEFHOOK
1015 (finish,
1016 "This hook is executed by the scheduler at the end of each block of\n\
1017 instructions that are to be scheduled. It can be used to perform\n\
1018 cleanup of any actions done by the other scheduling hooks. @var{file}\n\
1019 is either a null pointer, or a stdio stream to write any debug output\n\
1020 to. @var{verbose} is the verbose level provided by\n\
1021 @option{-fsched-verbose-@var{n}}.",
1022 void, (FILE *file, int verbose), NULL)
1024 /* Initialize machine-dependent function wide scheduling code. */
1025 DEFHOOK
1026 (init_global,
1027 "This hook is executed by the scheduler after function level initializations.\n\
1028 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1029 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1030 @var{old_max_uid} is the maximum insn uid when scheduling begins.",
1031 void, (FILE *file, int verbose, int old_max_uid), NULL)
1033 /* Finalize machine-dependent function wide scheduling code. */
1034 DEFHOOK
1035 (finish_global,
1036 "This is the cleanup hook corresponding to @code{TARGET_SCHED_INIT_GLOBAL}.\n\
1037 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1038 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.",
1039 void, (FILE *file, int verbose), NULL)
1041 /* Reorder insns in a machine-dependent fashion, in two different
1042 places. Default does nothing. */
1043 DEFHOOK
1044 (reorder,
1045 "This hook is executed by the scheduler after it has scheduled the ready\n\
1046 list, to allow the machine description to reorder it (for example to\n\
1047 combine two small instructions together on @samp{VLIW} machines).\n\
1048 @var{file} is either a null pointer, or a stdio stream to write any\n\
1049 debug output to. @var{verbose} is the verbose level provided by\n\
1050 @option{-fsched-verbose-@var{n}}. @var{ready} is a pointer to the ready\n\
1051 list of instructions that are ready to be scheduled. @var{n_readyp} is\n\
1052 a pointer to the number of elements in the ready list. The scheduler\n\
1053 reads the ready list in reverse order, starting with\n\
1054 @var{ready}[@var{*n_readyp} @minus{} 1] and going to @var{ready}[0]. @var{clock}\n\
1055 is the timer tick of the scheduler. You may modify the ready list and\n\
1056 the number of ready insns. The return value is the number of insns that\n\
1057 can issue this cycle; normally this is just @code{issue_rate}. See also\n\
1058 @samp{TARGET_SCHED_REORDER2}.",
1059 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1061 DEFHOOK
1062 (reorder2,
1063 "Like @samp{TARGET_SCHED_REORDER}, but called at a different time. That\n\
1064 function is called whenever the scheduler starts a new cycle. This one\n\
1065 is called once per iteration over a cycle, immediately after\n\
1066 @samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and\n\
1067 return the number of insns to be scheduled in the same cycle. Defining\n\
1068 this hook can be useful if there are frequent situations where\n\
1069 scheduling one insn causes other insns to become ready in the same\n\
1070 cycle. These other insns can then be taken into account properly.",
1071 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1073 DEFHOOK
1074 (macro_fusion_p,
1075 "This hook is used to check whether target platform supports macro fusion.",
1076 bool, (void), NULL)
1078 DEFHOOK
1079 (macro_fusion_pair_p,
1080 "This hook is used to check whether two insns should be macro fused for\n\
1081 a target microarchitecture. If this hook returns true for the given insn pair\n\
1082 (@var{prev} and @var{curr}), the scheduler will put them into a sched\n\
1083 group, and they will not be scheduled apart. The two insns will be either\n\
1084 two SET insns or a compare and a conditional jump and this hook should\n\
1085 validate any dependencies needed to fuse the two insns together.",
1086 bool, (rtx_insn *prev, rtx_insn *curr), NULL)
1088 /* The following member value is a pointer to a function called
1089 after evaluation forward dependencies of insns in chain given
1090 by two parameter values (head and tail correspondingly). */
1091 DEFHOOK
1092 (dependencies_evaluation_hook,
1093 "This hook is called after evaluation forward dependencies of insns in\n\
1094 chain given by two parameter values (@var{head} and @var{tail}\n\
1095 correspondingly) but before insns scheduling of the insn chain. For\n\
1096 example, it can be used for better insn classification if it requires\n\
1097 analysis of dependencies. This hook can use backward and forward\n\
1098 dependencies of the insn scheduler because they are already\n\
1099 calculated.",
1100 void, (rtx_insn *head, rtx_insn *tail), NULL)
1102 /* The values of the following four members are pointers to functions
1103 used to simplify the automaton descriptions. dfa_pre_cycle_insn and
1104 dfa_post_cycle_insn give functions returning insns which are used to
1105 change the pipeline hazard recognizer state when the new simulated
1106 processor cycle correspondingly starts and finishes. The function
1107 defined by init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are
1108 used to initialize the corresponding insns. The default values of
1109 the members result in not changing the automaton state when the
1110 new simulated processor cycle correspondingly starts and finishes. */
1112 DEFHOOK
1113 (init_dfa_pre_cycle_insn,
1114 "The hook can be used to initialize data used by the previous hook.",
1115 void, (void), NULL)
1117 DEFHOOK
1118 (dfa_pre_cycle_insn,
1119 "The hook returns an RTL insn. The automaton state used in the\n\
1120 pipeline hazard recognizer is changed as if the insn were scheduled\n\
1121 when the new simulated processor cycle starts. Usage of the hook may\n\
1122 simplify the automaton pipeline description for some @acronym{VLIW}\n\
1123 processors. If the hook is defined, it is used only for the automaton\n\
1124 based pipeline description. The default is not to change the state\n\
1125 when the new simulated processor cycle starts.",
1126 rtx, (void), NULL)
1128 DEFHOOK
1129 (init_dfa_post_cycle_insn,
1130 "The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but\n\
1131 used to initialize data used by the previous hook.",
1132 void, (void), NULL)
1134 DEFHOOK
1135 (dfa_post_cycle_insn,
1136 "The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1137 to changed the state as if the insn were scheduled when the new\n\
1138 simulated processor cycle finishes.",
1139 rtx_insn *, (void), NULL)
1141 /* The values of the following two members are pointers to
1142 functions used to simplify the automaton descriptions.
1143 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
1144 immediately before and after cycle is advanced. */
1146 DEFHOOK
1147 (dfa_pre_advance_cycle,
1148 "The hook to notify target that the current simulated cycle is about to finish.\n\
1149 The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1150 to change the state in more complicated situations - e.g., when advancing\n\
1151 state on a single insn is not enough.",
1152 void, (void), NULL)
1154 DEFHOOK
1155 (dfa_post_advance_cycle,
1156 "The hook to notify target that new simulated cycle has just started.\n\
1157 The hook is analogous to @samp{TARGET_SCHED_DFA_POST_CYCLE_INSN} but used\n\
1158 to change the state in more complicated situations - e.g., when advancing\n\
1159 state on a single insn is not enough.",
1160 void, (void), NULL)
1162 /* The following member value is a pointer to a function returning value
1163 which defines how many insns in queue `ready' will we try for
1164 multi-pass scheduling. If the member value is nonzero and the
1165 function returns positive value, the DFA based scheduler will make
1166 multi-pass scheduling for the first cycle. In other words, we will
1167 try to choose ready insn which permits to start maximum number of
1168 insns on the same cycle. */
1169 DEFHOOK
1170 (first_cycle_multipass_dfa_lookahead,
1171 "This hook controls better choosing an insn from the ready insn queue\n\
1172 for the @acronym{DFA}-based insn scheduler. Usually the scheduler\n\
1173 chooses the first insn from the queue. If the hook returns a positive\n\
1174 value, an additional scheduler code tries all permutations of\n\
1175 @samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}\n\
1176 subsequent ready insns to choose an insn whose issue will result in\n\
1177 maximal number of issued insns on the same cycle. For the\n\
1178 @acronym{VLIW} processor, the code could actually solve the problem of\n\
1179 packing simple insns into the @acronym{VLIW} insn. Of course, if the\n\
1180 rules of @acronym{VLIW} packing are described in the automaton.\n\
1182 This code also could be used for superscalar @acronym{RISC}\n\
1183 processors. Let us consider a superscalar @acronym{RISC} processor\n\
1184 with 3 pipelines. Some insns can be executed in pipelines @var{A} or\n\
1185 @var{B}, some insns can be executed only in pipelines @var{B} or\n\
1186 @var{C}, and one insn can be executed in pipeline @var{B}. The\n\
1187 processor may issue the 1st insn into @var{A} and the 2nd one into\n\
1188 @var{B}. In this case, the 3rd insn will wait for freeing @var{B}\n\
1189 until the next cycle. If the scheduler issues the 3rd insn the first,\n\
1190 the processor could issue all 3 insns per cycle.\n\
1192 Actually this code demonstrates advantages of the automaton based\n\
1193 pipeline hazard recognizer. We try quickly and easy many insn\n\
1194 schedules to choose the best one.\n\
1196 The default is no multipass scheduling.",
1197 int, (void), NULL)
1199 /* The following member value is pointer to a function controlling
1200 what insns from the ready insn queue will be considered for the
1201 multipass insn scheduling. If the hook returns zero for insn
1202 passed as the parameter, the insn will be not chosen to be issued. */
1203 DEFHOOK
1204 (first_cycle_multipass_dfa_lookahead_guard,
1205 "\n\
1206 This hook controls what insns from the ready insn queue will be\n\
1207 considered for the multipass insn scheduling. If the hook returns\n\
1208 zero for @var{insn}, the insn will be considered in multipass scheduling.\n\
1209 Positive return values will remove @var{insn} from consideration on\n\
1210 the current round of multipass scheduling.\n\
1211 Negative return values will remove @var{insn} from consideration for given\n\
1212 number of cycles.\n\
1213 Backends should be careful about returning non-zero for highest priority\n\
1214 instruction at position 0 in the ready list. @var{ready_index} is passed\n\
1215 to allow backends make correct judgements.\n\
1217 The default is that any ready insns can be chosen to be issued.",
1218 int, (rtx_insn *insn, int ready_index), NULL)
1220 /* This hook prepares the target for a new round of multipass
1221 scheduling.
1222 DATA is a pointer to target-specific data used for multipass scheduling.
1223 READY_TRY and N_READY represent the current state of search in the
1224 optimization space. The target can filter out instructions that
1225 should not be tried during current round by setting corresponding
1226 elements in READY_TRY to non-zero.
1227 FIRST_CYCLE_INSN_P is true if this is the first round of multipass
1228 scheduling on current cycle. */
1229 DEFHOOK
1230 (first_cycle_multipass_begin,
1231 "This hook prepares the target backend for a new round of multipass\n\
1232 scheduling.",
1233 void, (void *data, signed char *ready_try, int n_ready, bool first_cycle_insn_p),
1234 NULL)
1236 /* This hook is called when multipass scheduling evaluates instruction INSN.
1237 DATA is a pointer to target-specific data that can be used to record effects
1238 of INSN on CPU that are not described in DFA.
1239 READY_TRY and N_READY represent the current state of search in the
1240 optimization space. The target can filter out instructions that
1241 should not be tried after issuing INSN by setting corresponding
1242 elements in READY_TRY to non-zero.
1243 INSN is the instruction being evaluated.
1244 PREV_DATA is a pointer to target-specific data corresponding
1245 to a state before issuing INSN. */
1246 DEFHOOK
1247 (first_cycle_multipass_issue,
1248 "This hook is called when multipass scheduling evaluates instruction INSN.",
1249 void, (void *data, signed char *ready_try, int n_ready, rtx_insn *insn,
1250 const void *prev_data), NULL)
1252 /* This hook is called when multipass scheduling backtracks from evaluation of
1253 instruction corresponding to DATA.
1254 DATA is a pointer to target-specific data that stores the effects
1255 of instruction from which the algorithm backtracks on CPU that are not
1256 described in DFA.
1257 READY_TRY and N_READY represent the current state of search in the
1258 optimization space. The target can filter out instructions that
1259 should not be tried after issuing INSN by setting corresponding
1260 elements in READY_TRY to non-zero. */
1261 DEFHOOK
1262 (first_cycle_multipass_backtrack,
1263 "This is called when multipass scheduling backtracks from evaluation of\n\
1264 an instruction.",
1265 void, (const void *data, signed char *ready_try, int n_ready), NULL)
1267 /* This hook notifies the target about the result of the concluded current
1268 round of multipass scheduling.
1269 DATA is a pointer.
1270 If DATA is non-NULL it points to target-specific data used for multipass
1271 scheduling which corresponds to instruction at the start of the chain of
1272 the winning solution. DATA is NULL when multipass scheduling cannot find
1273 a good enough solution on current cycle and decides to retry later,
1274 usually after advancing the cycle count. */
1275 DEFHOOK
1276 (first_cycle_multipass_end,
1277 "This hook notifies the target about the result of the concluded current\n\
1278 round of multipass scheduling.",
1279 void, (const void *data), NULL)
1281 /* This hook is called to initialize target-specific data for multipass
1282 scheduling after it has been allocated.
1283 DATA is a pointer to target-specific data that stores the effects
1284 of instruction from which the algorithm backtracks on CPU that are not
1285 described in DFA. */
1286 DEFHOOK
1287 (first_cycle_multipass_init,
1288 "This hook initializes target-specific data used in multipass scheduling.",
1289 void, (void *data), NULL)
1291 /* This hook is called to finalize target-specific data for multipass
1292 scheduling before it is deallocated.
1293 DATA is a pointer to target-specific data that stores the effects
1294 of instruction from which the algorithm backtracks on CPU that are not
1295 described in DFA. */
1296 DEFHOOK
1297 (first_cycle_multipass_fini,
1298 "This hook finalizes target-specific data used in multipass scheduling.",
1299 void, (void *data), NULL)
1301 /* The following member value is pointer to a function called by
1302 the insn scheduler before issuing insn passed as the third
1303 parameter on given cycle. If the hook returns nonzero, the
1304 insn is not issued on given processors cycle. Instead of that,
1305 the processor cycle is advanced. If the value passed through
1306 the last parameter is zero, the insn ready queue is not sorted
1307 on the new cycle start as usually. The first parameter passes
1308 file for debugging output. The second one passes the scheduler
1309 verbose level of the debugging output. The forth and the fifth
1310 parameter values are correspondingly processor cycle on which
1311 the previous insn has been issued and the current processor cycle. */
1312 DEFHOOK
1313 (dfa_new_cycle,
1314 "This hook is called by the insn scheduler before issuing @var{insn}\n\
1315 on cycle @var{clock}. If the hook returns nonzero,\n\
1316 @var{insn} is not issued on this processor cycle. Instead,\n\
1317 the processor cycle is advanced. If *@var{sort_p}\n\
1318 is zero, the insn ready queue is not sorted on the new cycle\n\
1319 start as usually. @var{dump} and @var{verbose} specify the file and\n\
1320 verbosity level to use for debugging output.\n\
1321 @var{last_clock} and @var{clock} are, respectively, the\n\
1322 processor cycle on which the previous insn has been issued,\n\
1323 and the current processor cycle.",
1324 int, (FILE *dump, int verbose, rtx_insn *insn, int last_clock,
1325 int clock, int *sort_p),
1326 NULL)
1328 /* The following member value is a pointer to a function called by the
1329 insn scheduler. It should return true if there exists a dependence
1330 which is considered costly by the target, between the insn
1331 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
1332 the dep that represents the dependence between the two insns. The
1333 second argument is the cost of the dependence as estimated by
1334 the scheduler. The last argument is the distance in cycles
1335 between the already scheduled insn (first parameter) and the
1336 second insn (second parameter). */
1337 DEFHOOK
1338 (is_costly_dependence,
1339 "This hook is used to define which dependences are considered costly by\n\
1340 the target, so costly that it is not advisable to schedule the insns that\n\
1341 are involved in the dependence too close to one another. The parameters\n\
1342 to this hook are as follows: The first parameter @var{_dep} is the dependence\n\
1343 being evaluated. The second parameter @var{cost} is the cost of the\n\
1344 dependence as estimated by the scheduler, and the third\n\
1345 parameter @var{distance} is the distance in cycles between the two insns.\n\
1346 The hook returns @code{true} if considering the distance between the two\n\
1347 insns the dependence between them is considered costly by the target,\n\
1348 and @code{false} otherwise.\n\
1350 Defining this hook can be useful in multiple-issue out-of-order machines,\n\
1351 where (a) it's practically hopeless to predict the actual data/resource\n\
1352 delays, however: (b) there's a better chance to predict the actual grouping\n\
1353 that will be formed, and (c) correctly emulating the grouping can be very\n\
1354 important. In such targets one may want to allow issuing dependent insns\n\
1355 closer to one another---i.e., closer than the dependence distance; however,\n\
1356 not in cases of ``costly dependences'', which this hooks allows to define.",
1357 bool, (struct _dep *_dep, int cost, int distance), NULL)
1359 /* The following member value is a pointer to a function called
1360 by the insn scheduler. This hook is called to notify the backend
1361 that new instructions were emitted. */
1362 DEFHOOK
1363 (h_i_d_extended,
1364 "This hook is called by the insn scheduler after emitting a new instruction to\n\
1365 the instruction stream. The hook notifies a target backend to extend its\n\
1366 per instruction data structures.",
1367 void, (void), NULL)
1369 /* Next 5 functions are for multi-point scheduling. */
1371 /* Allocate memory for scheduler context. */
1372 DEFHOOK
1373 (alloc_sched_context,
1374 "Return a pointer to a store large enough to hold target scheduling context.",
1375 void *, (void), NULL)
1377 /* Fills the context from the local machine scheduler context. */
1378 DEFHOOK
1379 (init_sched_context,
1380 "Initialize store pointed to by @var{tc} to hold target scheduling context.\n\
1381 It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the\n\
1382 beginning of the block. Otherwise, copy the current context into @var{tc}.",
1383 void, (void *tc, bool clean_p), NULL)
1385 /* Sets local machine scheduler context to a saved value. */
1386 DEFHOOK
1387 (set_sched_context,
1388 "Copy target scheduling context pointed to by @var{tc} to the current context.",
1389 void, (void *tc), NULL)
1391 /* Clears a scheduler context so it becomes like after init. */
1392 DEFHOOK
1393 (clear_sched_context,
1394 "Deallocate internal data in target scheduling context pointed to by @var{tc}.",
1395 void, (void *tc), NULL)
1397 /* Frees the scheduler context. */
1398 DEFHOOK
1399 (free_sched_context,
1400 "Deallocate a store for target scheduling context pointed to by @var{tc}.",
1401 void, (void *tc), NULL)
1403 /* The following member value is a pointer to a function called
1404 by the insn scheduler.
1405 The first parameter is an instruction, the second parameter is the type
1406 of the requested speculation, and the third parameter is a pointer to the
1407 speculative pattern of the corresponding type (set if return value == 1).
1408 It should return
1409 -1, if there is no pattern, that will satisfy the requested speculation type,
1410 0, if current pattern satisfies the requested speculation type,
1411 1, if pattern of the instruction should be changed to the newly
1412 generated one. */
1413 DEFHOOK
1414 (speculate_insn,
1415 "This hook is called by the insn scheduler when @var{insn} has only\n\
1416 speculative dependencies and therefore can be scheduled speculatively.\n\
1417 The hook is used to check if the pattern of @var{insn} has a speculative\n\
1418 version and, in case of successful check, to generate that speculative\n\
1419 pattern. The hook should return 1, if the instruction has a speculative form,\n\
1420 or @minus{}1, if it doesn't. @var{request} describes the type of requested\n\
1421 speculation. If the return value equals 1 then @var{new_pat} is assigned\n\
1422 the generated speculative pattern.",
1423 int, (rtx_insn *insn, unsigned int dep_status, rtx *new_pat), NULL)
1425 /* The following member value is a pointer to a function called
1426 by the insn scheduler. It should return true if the check instruction
1427 passed as the parameter needs a recovery block. */
1428 DEFHOOK
1429 (needs_block_p,
1430 "This hook is called by the insn scheduler during generation of recovery code\n\
1431 for @var{insn}. It should return @code{true}, if the corresponding check\n\
1432 instruction should branch to recovery code, or @code{false} otherwise.",
1433 bool, (unsigned int dep_status), NULL)
1435 /* The following member value is a pointer to a function called
1436 by the insn scheduler. It should return a pattern for the check
1437 instruction.
1438 The first parameter is a speculative instruction, the second parameter
1439 is the label of the corresponding recovery block (or null, if it is a
1440 simple check). The third parameter is the kind of speculation that
1441 is being performed. */
1442 DEFHOOK
1443 (gen_spec_check,
1444 "This hook is called by the insn scheduler to generate a pattern for recovery\n\
1445 check instruction. If @var{mutate_p} is zero, then @var{insn} is a\n\
1446 speculative instruction for which the check should be generated.\n\
1447 @var{label} is either a label of a basic block, where recovery code should\n\
1448 be emitted, or a null pointer, when requested check doesn't branch to\n\
1449 recovery code (a simple check). If @var{mutate_p} is nonzero, then\n\
1450 a pattern for a branchy check corresponding to a simple check denoted by\n\
1451 @var{insn} should be generated. In this case @var{label} can't be null.",
1452 rtx, (rtx_insn *insn, rtx_insn *label, unsigned int ds), NULL)
1454 /* The following member value is a pointer to a function that provides
1455 information about the speculation capabilities of the target.
1456 The parameter is a pointer to spec_info variable. */
1457 DEFHOOK
1458 (set_sched_flags,
1459 "This hook is used by the insn scheduler to find out what features should be\n\
1460 enabled/used.\n\
1461 The structure *@var{spec_info} should be filled in by the target.\n\
1462 The structure describes speculation types that can be used in the scheduler.",
1463 void, (struct spec_info_def *spec_info), NULL)
1465 DEFHOOK_UNDOC
1466 (get_insn_spec_ds,
1467 "Return speculation types of instruction @var{insn}.",
1468 unsigned int, (rtx_insn *insn), NULL)
1470 DEFHOOK_UNDOC
1471 (get_insn_checked_ds,
1472 "Return speculation types that are checked for instruction @var{insn}",
1473 unsigned int, (rtx_insn *insn), NULL)
1475 DEFHOOK
1476 (can_speculate_insn,
1477 "Some instructions should never be speculated by the schedulers, usually\n\
1478 because the instruction is too expensive to get this wrong. Often such\n\
1479 instructions have long latency, and often they are not fully modeled in the\n\
1480 pipeline descriptions. This hook should return @code{false} if @var{insn}\n\
1481 should not be speculated.",
1482 bool, (rtx_insn *insn), hook_bool_rtx_insn_true)
1484 DEFHOOK_UNDOC
1485 (skip_rtx_p,
1486 "Return bool if rtx scanning should just skip current layer and\
1487 advance to the inner rtxes.",
1488 bool, (const_rtx x), NULL)
1490 /* The following member value is a pointer to a function that provides
1491 information about the target resource-based lower bound which is
1492 used by the swing modulo scheduler. The parameter is a pointer
1493 to ddg variable. */
1494 DEFHOOK
1495 (sms_res_mii,
1496 "This hook is called by the swing modulo scheduler to calculate a\n\
1497 resource-based lower bound which is based on the resources available in\n\
1498 the machine and the resources required by each instruction. The target\n\
1499 backend can use @var{g} to calculate such bound. A very simple lower\n\
1500 bound will be used in case this hook is not implemented: the total number\n\
1501 of instructions divided by the issue rate.",
1502 int, (struct ddg *g), NULL)
1504 /* The following member value is a function that initializes dispatch
1505 schedling and adds instructions to dispatch window according to its
1506 parameters. */
1507 DEFHOOK
1508 (dispatch_do,
1509 "This hook is called by Haifa Scheduler. It performs the operation specified\n\
1510 in its second parameter.",
1511 void, (rtx_insn *insn, int x),
1512 hook_void_rtx_insn_int)
1514 /* The following member value is a function that returns true is
1515 dispatch schedling is supported in hardware and condition passed
1516 as the second parameter is true. */
1517 DEFHOOK
1518 (dispatch,
1519 "This hook is called by Haifa Scheduler. It returns true if dispatch scheduling\n\
1520 is supported in hardware and the condition specified in the parameter is true.",
1521 bool, (rtx_insn *insn, int x),
1522 hook_bool_rtx_insn_int_false)
1524 DEFHOOKPOD
1525 (exposed_pipeline,
1526 "True if the processor has an exposed pipeline, which means that not just\n\
1527 the order of instructions is important for correctness when scheduling, but\n\
1528 also the latencies of operations.",
1529 bool, false)
1531 /* The following member value is a function that returns number
1532 of operations reassociator should try to put in parallel for
1533 statements of the given type. By default 1 is used. */
1534 DEFHOOK
1535 (reassociation_width,
1536 "This hook is called by tree reassociator to determine a level of\n\
1537 parallelism required in output calculations chain.",
1538 int, (unsigned int opc, machine_mode mode),
1539 hook_int_uint_mode_1)
1541 /* The following member value is a function that returns priority for
1542 fusion of each instruction via pointer parameters. */
1543 DEFHOOK
1544 (fusion_priority,
1545 "This hook is called by scheduling fusion pass. It calculates fusion\n\
1546 priorities for each instruction passed in by parameter. The priorities\n\
1547 are returned via pointer parameters.\n\
1549 @var{insn} is the instruction whose priorities need to be calculated.\n\
1550 @var{max_pri} is the maximum priority can be returned in any cases.\n\
1551 @var{fusion_pri} is the pointer parameter through which @var{insn}'s\n\
1552 fusion priority should be calculated and returned.\n\
1553 @var{pri} is the pointer parameter through which @var{insn}'s priority\n\
1554 should be calculated and returned.\n\
1556 Same @var{fusion_pri} should be returned for instructions which should\n\
1557 be scheduled together. Different @var{pri} should be returned for\n\
1558 instructions with same @var{fusion_pri}. @var{fusion_pri} is the major\n\
1559 sort key, @var{pri} is the minor sort key. All instructions will be\n\
1560 scheduled according to the two priorities. All priorities calculated\n\
1561 should be between 0 (exclusive) and @var{max_pri} (inclusive). To avoid\n\
1562 false dependencies, @var{fusion_pri} of instructions which need to be\n\
1563 scheduled together should be smaller than @var{fusion_pri} of irrelevant\n\
1564 instructions.\n\
1566 Given below example:\n\
1568 @smallexample\n\
1569 ldr r10, [r1, 4]\n\
1570 add r4, r4, r10\n\
1571 ldr r15, [r2, 8]\n\
1572 sub r5, r5, r15\n\
1573 ldr r11, [r1, 0]\n\
1574 add r4, r4, r11\n\
1575 ldr r16, [r2, 12]\n\
1576 sub r5, r5, r16\n\
1577 @end smallexample\n\
1579 On targets like ARM/AArch64, the two pairs of consecutive loads should be\n\
1580 merged. Since peephole2 pass can't help in this case unless consecutive\n\
1581 loads are actually next to each other in instruction flow. That's where\n\
1582 this scheduling fusion pass works. This hook calculates priority for each\n\
1583 instruction based on its fustion type, like:\n\
1585 @smallexample\n\
1586 ldr r10, [r1, 4] ; fusion_pri=99, pri=96\n\
1587 add r4, r4, r10 ; fusion_pri=100, pri=100\n\
1588 ldr r15, [r2, 8] ; fusion_pri=98, pri=92\n\
1589 sub r5, r5, r15 ; fusion_pri=100, pri=100\n\
1590 ldr r11, [r1, 0] ; fusion_pri=99, pri=100\n\
1591 add r4, r4, r11 ; fusion_pri=100, pri=100\n\
1592 ldr r16, [r2, 12] ; fusion_pri=98, pri=88\n\
1593 sub r5, r5, r16 ; fusion_pri=100, pri=100\n\
1594 @end smallexample\n\
1596 Scheduling fusion pass then sorts all ready to issue instructions according\n\
1597 to the priorities. As a result, instructions of same fusion type will be\n\
1598 pushed together in instruction flow, like:\n\
1600 @smallexample\n\
1601 ldr r11, [r1, 0]\n\
1602 ldr r10, [r1, 4]\n\
1603 ldr r15, [r2, 8]\n\
1604 ldr r16, [r2, 12]\n\
1605 add r4, r4, r10\n\
1606 sub r5, r5, r15\n\
1607 add r4, r4, r11\n\
1608 sub r5, r5, r16\n\
1609 @end smallexample\n\
1611 Now peephole2 pass can simply merge the two pairs of loads.\n\
1613 Since scheduling fusion pass relies on peephole2 to do real fusion\n\
1614 work, it is only enabled by default when peephole2 is in effect.\n\
1616 This is firstly introduced on ARM/AArch64 targets, please refer to\n\
1617 the hook implementation for how different fusion types are supported.",
1618 void, (rtx_insn *insn, int max_pri, int *fusion_pri, int *pri), NULL)
1620 HOOK_VECTOR_END (sched)
1622 /* Functions relating to OpenMP SIMD and __attribute__((simd)) clones. */
1623 #undef HOOK_PREFIX
1624 #define HOOK_PREFIX "TARGET_SIMD_CLONE_"
1625 HOOK_VECTOR (TARGET_SIMD_CLONE, simd_clone)
1627 DEFHOOK
1628 (compute_vecsize_and_simdlen,
1629 "This hook should set @var{vecsize_mangle}, @var{vecsize_int}, @var{vecsize_float}\n\
1630 fields in @var{simd_clone} structure pointed by @var{clone_info} argument and also\n\
1631 @var{simdlen} field if it was previously 0.\n\
1632 @var{vecsize_mangle} is a marker for the backend only. @var{vecsize_int} and\n\
1633 @var{vecsize_float} should be left zero on targets where the number of lanes is\n\
1634 not determined by the bitsize (in which case @var{simdlen} is always used).\n\
1635 The hook should return 0 if SIMD clones shouldn't be emitted,\n\
1636 or number of @var{vecsize_mangle} variants that should be emitted.",
1637 int, (struct cgraph_node *, struct cgraph_simd_clone *, tree, int, bool), NULL)
1639 DEFHOOK
1640 (adjust,
1641 "This hook should add implicit @code{attribute(target(\"...\"))} attribute\n\
1642 to SIMD clone @var{node} if needed.",
1643 void, (struct cgraph_node *), NULL)
1645 DEFHOOK
1646 (usable,
1647 "This hook should return -1 if SIMD clone @var{node} shouldn't be used\n\
1648 in vectorized loops in current function, or non-negative number if it is\n\
1649 usable. In that case, the smaller the number is, the more desirable it is\n\
1650 to use it.",
1651 int, (struct cgraph_node *), NULL)
1653 HOOK_VECTOR_END (simd_clone)
1655 /* Functions relating to OpenMP SIMT vectorization transform. */
1656 #undef HOOK_PREFIX
1657 #define HOOK_PREFIX "TARGET_SIMT_"
1658 HOOK_VECTOR (TARGET_SIMT, simt)
1660 DEFHOOK
1661 (vf,
1662 "Return number of threads in SIMT thread group on the target.",
1663 int, (void), NULL)
1665 HOOK_VECTOR_END (simt)
1667 /* Functions relating to OpenMP. */
1668 #undef HOOK_PREFIX
1669 #define HOOK_PREFIX "TARGET_OMP_"
1670 HOOK_VECTOR (TARGET_OMP, omp)
1672 DEFHOOK
1673 (device_kind_arch_isa,
1674 "Return 1 if @var{trait} @var{name} is present in the OpenMP context's\n\
1675 device trait set, return 0 if not present in any OpenMP context in the\n\
1676 whole translation unit, or -1 if not present in the current OpenMP context\n\
1677 but might be present in another OpenMP context in the same TU.",
1678 int, (enum omp_device_kind_arch_isa trait, const char *name), NULL)
1680 HOOK_VECTOR_END (omp)
1682 /* Functions relating to openacc. */
1683 #undef HOOK_PREFIX
1684 #define HOOK_PREFIX "TARGET_GOACC_"
1685 HOOK_VECTOR (TARGET_GOACC, goacc)
1687 DEFHOOK
1688 (validate_dims,
1689 "This hook should check the launch dimensions provided for an OpenACC\n\
1690 compute region, or routine. Defaulted values are represented as -1\n\
1691 and non-constant values as 0. The @var{fn_level} is negative for the\n\
1692 function corresponding to the compute region. For a routine it is the\n\
1693 outermost level at which partitioned execution may be spawned. The hook\n\
1694 should verify non-default values. If DECL is NULL, global defaults\n\
1695 are being validated and unspecified defaults should be filled in.\n\
1696 Diagnostics should be issued as appropriate. Return\n\
1697 true, if changes have been made. You must override this hook to\n\
1698 provide dimensions larger than 1.",
1699 bool, (tree decl, int *dims, int fn_level, unsigned used),
1700 default_goacc_validate_dims)
1702 DEFHOOK
1703 (dim_limit,
1704 "This hook should return the maximum size of a particular dimension,\n\
1705 or zero if unbounded.",
1706 int, (int axis),
1707 default_goacc_dim_limit)
1709 DEFHOOK
1710 (fork_join,
1711 "This hook can be used to convert IFN_GOACC_FORK and IFN_GOACC_JOIN\n\
1712 function calls to target-specific gimple, or indicate whether they\n\
1713 should be retained. It is executed during the oacc_device_lower pass.\n\
1714 It should return true, if the call should be retained. It should\n\
1715 return false, if it is to be deleted (either because target-specific\n\
1716 gimple has been inserted before it, or there is no need for it).\n\
1717 The default hook returns false, if there are no RTL expanders for them.",
1718 bool, (gcall *call, const int *dims, bool is_fork),
1719 default_goacc_fork_join)
1721 DEFHOOK
1722 (reduction,
1723 "This hook is used by the oacc_transform pass to expand calls to the\n\
1724 @var{GOACC_REDUCTION} internal function, into a sequence of gimple\n\
1725 instructions. @var{call} is gimple statement containing the call to\n\
1726 the function. This hook removes statement @var{call} after the\n\
1727 expanded sequence has been inserted. This hook is also responsible\n\
1728 for allocating any storage for reductions when necessary.",
1729 void, (gcall *call),
1730 default_goacc_reduction)
1732 DEFHOOK
1733 (adjust_private_decl,
1734 "This hook, if defined, is used by accelerator target back-ends to adjust\n\
1735 OpenACC variable declarations that should be made private to the given\n\
1736 parallelism level (i.e. @code{GOMP_DIM_GANG}, @code{GOMP_DIM_WORKER} or\n\
1737 @code{GOMP_DIM_VECTOR}). A typical use for this hook is to force variable\n\
1738 declarations at the @code{gang} level to reside in GPU shared memory.\n\
1739 @var{loc} may be used for diagnostic purposes.\n\
1741 You may also use the @code{TARGET_GOACC_EXPAND_VAR_DECL} hook if the\n\
1742 adjusted variable declaration needs to be expanded to RTL in a non-standard\n\
1743 way.",
1744 tree, (location_t loc, tree var, int level),
1745 NULL)
1747 DEFHOOK
1748 (expand_var_decl,
1749 "This hook, if defined, is used by accelerator target back-ends to expand\n\
1750 specially handled kinds of @code{VAR_DECL} expressions. A particular use is\n\
1751 to place variables with specific attributes inside special accelarator\n\
1752 memories. A return value of @code{NULL} indicates that the target does not\n\
1753 handle this @code{VAR_DECL}, and normal RTL expanding is resumed.\n\
1755 Only define this hook if your accelerator target needs to expand certain\n\
1756 @code{VAR_DECL} nodes in a way that differs from the default. You can also adjust\n\
1757 private variables at OpenACC device-lowering time using the\n\
1758 @code{TARGET_GOACC_ADJUST_PRIVATE_DECL} target hook.",
1759 rtx, (tree var),
1760 NULL)
1762 DEFHOOK
1763 (create_worker_broadcast_record,
1764 "Create a record used to propagate local-variable state from an active\n\
1765 worker to other workers. A possible implementation might adjust the type\n\
1766 of REC to place the new variable in shared GPU memory.\n\
1768 Presence of this target hook indicates that middle end neutering/broadcasting\n\
1769 be used.",
1770 tree, (tree rec, bool sender, const char *name, unsigned HOST_WIDE_INT offset),
1771 NULL)
1773 DEFHOOK
1774 (shared_mem_layout,
1775 "Lay out a fixed shared-memory region on the target. The LO and HI\n\
1776 arguments should be set to a range of addresses that can be used for worker\n\
1777 broadcasting. The dimensions, reduction size and gang-private size\n\
1778 arguments are for the current offload region.",
1779 void, (unsigned HOST_WIDE_INT *, unsigned HOST_WIDE_INT *, int[],
1780 unsigned HOST_WIDE_INT[], unsigned HOST_WIDE_INT[]),
1781 NULL)
1783 HOOK_VECTOR_END (goacc)
1785 /* Functions relating to vectorization. */
1786 #undef HOOK_PREFIX
1787 #define HOOK_PREFIX "TARGET_VECTORIZE_"
1788 HOOK_VECTOR (TARGET_VECTORIZE, vectorize)
1790 /* The following member value is a pointer to a function called
1791 by the vectorizer, and return the decl of the target builtin
1792 function. */
1793 DEFHOOK
1794 (builtin_mask_for_load,
1795 "This hook should return the DECL of a function @var{f} that given an\n\
1796 address @var{addr} as an argument returns a mask @var{m} that can be\n\
1797 used to extract from two vectors the relevant data that resides in\n\
1798 @var{addr} in case @var{addr} is not properly aligned.\n\
1800 The autovectorizer, when vectorizing a load operation from an address\n\
1801 @var{addr} that may be unaligned, will generate two vector loads from\n\
1802 the two aligned addresses around @var{addr}. It then generates a\n\
1803 @code{REALIGN_LOAD} operation to extract the relevant data from the\n\
1804 two loaded vectors. The first two arguments to @code{REALIGN_LOAD},\n\
1805 @var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and\n\
1806 the third argument, @var{OFF}, defines how the data will be extracted\n\
1807 from these two vectors: if @var{OFF} is 0, then the returned vector is\n\
1808 @var{v2}; otherwise, the returned vector is composed from the last\n\
1809 @var{VS}-@var{OFF} elements of @var{v1} concatenated to the first\n\
1810 @var{OFF} elements of @var{v2}.\n\
1812 If this hook is defined, the autovectorizer will generate a call\n\
1813 to @var{f} (using the DECL tree that this hook returns) and will\n\
1814 use the return value of @var{f} as the argument @var{OFF} to\n\
1815 @code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}\n\
1816 should comply with the semantics expected by @code{REALIGN_LOAD}\n\
1817 described above.\n\
1818 If this hook is not defined, then @var{addr} will be used as\n\
1819 the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low\n\
1820 log2(@var{VS}) @minus{} 1 bits of @var{addr} will be considered.",
1821 tree, (void), NULL)
1823 /* Returns a built-in function that realizes the vectorized version of
1824 a target-independent function, or NULL_TREE if not available. */
1825 DEFHOOK
1826 (builtin_vectorized_function,
1827 "This hook should return the decl of a function that implements the\n\
1828 vectorized variant of the function with the @code{combined_fn} code\n\
1829 @var{code} or @code{NULL_TREE} if such a function is not available.\n\
1830 The return type of the vectorized function shall be of vector type\n\
1831 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1832 tree, (unsigned code, tree vec_type_out, tree vec_type_in),
1833 default_builtin_vectorized_function)
1835 /* Returns a built-in function that realizes the vectorized version of
1836 a target-specific function, or NULL_TREE if not available. */
1837 DEFHOOK
1838 (builtin_md_vectorized_function,
1839 "This hook should return the decl of a function that implements the\n\
1840 vectorized variant of target built-in function @code{fndecl}. The\n\
1841 return type of the vectorized function shall be of vector type\n\
1842 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1843 tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
1844 default_builtin_md_vectorized_function)
1846 /* Cost of different vector/scalar statements in vectorization cost
1847 model. In case of misaligned vector loads and stores the cost depends
1848 on the data type and misalignment value. */
1849 DEFHOOK
1850 (builtin_vectorization_cost,
1851 "Returns cost of different scalar or vector statements for vectorization cost model.\n\
1852 For vector memory operations the cost may depend on type (@var{vectype}) and\n\
1853 misalignment value (@var{misalign}).",
1854 int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
1855 default_builtin_vectorization_cost)
1857 DEFHOOK
1858 (preferred_vector_alignment,
1859 "This hook returns the preferred alignment in bits for accesses to\n\
1860 vectors of type @var{type} in vectorized code. This might be less than\n\
1861 or greater than the ABI-defined value returned by\n\
1862 @code{TARGET_VECTOR_ALIGNMENT}. It can be equal to the alignment of\n\
1863 a single element, in which case the vectorizer will not try to optimize\n\
1864 for alignment.\n\
1866 The default hook returns @code{TYPE_ALIGN (@var{type})}, which is\n\
1867 correct for most targets.",
1868 poly_uint64, (const_tree type),
1869 default_preferred_vector_alignment)
1871 /* Returns whether the target has a preference for decomposing divisions using
1872 shifts rather than multiplies. */
1873 DEFHOOK
1874 (preferred_div_as_shifts_over_mult,
1875 "Sometimes it is possible to implement a vector division using a sequence\n\
1876 of two addition-shift pairs, giving four instructions in total.\n\
1877 Return true if taking this approach for @var{vectype} is likely\n\
1878 to be better than using a sequence involving highpart multiplication.\n\
1879 Default is false if @code{can_mult_highpart_p}, otherwise true.",
1880 bool, (const_tree type),
1881 default_preferred_div_as_shifts_over_mult)
1883 /* Return true if vector alignment is reachable (by peeling N
1884 iterations) for the given scalar type. */
1885 DEFHOOK
1886 (vector_alignment_reachable,
1887 "Return true if vector alignment is reachable (by peeling N iterations)\n\
1888 for the given scalar type @var{type}. @var{is_packed} is false if the scalar\n\
1889 access using @var{type} is known to be naturally aligned.",
1890 bool, (const_tree type, bool is_packed),
1891 default_builtin_vector_alignment_reachable)
1893 DEFHOOK
1894 (vec_perm_const,
1895 "This hook is used to test whether the target can permute up to two\n\
1896 vectors of mode @var{op_mode} using the permutation vector @code{sel},\n\
1897 producing a vector of mode @var{mode}. The hook is also used to emit such\n\
1898 a permutation.\n\
1900 When the hook is being used to test whether the target supports a permutation,\n\
1901 @var{in0}, @var{in1}, and @var{out} are all null. When the hook is being used\n\
1902 to emit a permutation, @var{in0} and @var{in1} are the source vectors of mode\n\
1903 @var{op_mode} and @var{out} is the destination vector of mode @var{mode}.\n\
1904 @var{in1} is the same as @var{in0} if @var{sel} describes a permutation on one\n\
1905 vector instead of two.\n\
1907 Return true if the operation is possible, emitting instructions for it\n\
1908 if rtxes are provided.\n\
1910 @cindex @code{vec_perm@var{m}} instruction pattern\n\
1911 If the hook returns false for a mode with multibyte elements, GCC will\n\
1912 try the equivalent byte operation. If that also fails, it will try forcing\n\
1913 the selector into a register and using the @var{vec_perm@var{mode}}\n\
1914 instruction pattern. There is no need for the hook to handle these two\n\
1915 implementation approaches itself.",
1916 bool, (machine_mode mode, machine_mode op_mode, rtx output, rtx in0, rtx in1,
1917 const vec_perm_indices &sel),
1918 NULL)
1920 /* Return true if the target supports misaligned store/load of a
1921 specific factor denoted in the third parameter. The last parameter
1922 is true if the access is defined in a packed struct. */
1923 DEFHOOK
1924 (support_vector_misalignment,
1925 "This hook should return true if the target supports misaligned vector\n\
1926 store/load of a specific factor denoted in the @var{misalignment}\n\
1927 parameter. The vector store/load should be of machine mode @var{mode} and\n\
1928 the elements in the vectors should be of type @var{type}. @var{is_packed}\n\
1929 parameter is true if the memory access is defined in a packed struct.",
1930 bool,
1931 (machine_mode mode, const_tree type, int misalignment, bool is_packed),
1932 default_builtin_support_vector_misalignment)
1934 /* Returns the preferred mode for SIMD operations for the specified
1935 scalar mode. */
1936 DEFHOOK
1937 (preferred_simd_mode,
1938 "This hook should return the preferred mode for vectorizing scalar\n\
1939 mode @var{mode}. The default is\n\
1940 equal to @code{word_mode}, because the vectorizer can do some\n\
1941 transformations even in absence of specialized @acronym{SIMD} hardware.",
1942 machine_mode,
1943 (scalar_mode mode),
1944 default_preferred_simd_mode)
1946 /* Returns the preferred mode for splitting SIMD reductions to. */
1947 DEFHOOK
1948 (split_reduction,
1949 "This hook should return the preferred mode to split the final reduction\n\
1950 step on @var{mode} to. The reduction is then carried out reducing upper\n\
1951 against lower halves of vectors recursively until the specified mode is\n\
1952 reached. The default is @var{mode} which means no splitting.",
1953 machine_mode,
1954 (machine_mode),
1955 default_split_reduction)
1957 /* Returns a mask of vector sizes to iterate over when auto-vectorizing
1958 after processing the preferred one derived from preferred_simd_mode. */
1959 DEFHOOK
1960 (autovectorize_vector_modes,
1961 "If using the mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}\n\
1962 is not the only approach worth considering, this hook should add one mode to\n\
1963 @var{modes} for each useful alternative approach. These modes are then\n\
1964 passed to @code{TARGET_VECTORIZE_RELATED_MODE} to obtain the vector mode\n\
1965 for a given element mode.\n\
1967 The modes returned in @var{modes} should use the smallest element mode\n\
1968 possible for the vectorization approach that they represent, preferring\n\
1969 integer modes over floating-poing modes in the event of a tie. The first\n\
1970 mode should be the @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE} for its\n\
1971 element mode.\n\
1973 If @var{all} is true, add suitable vector modes even when they are generally\n\
1974 not expected to be worthwhile.\n\
1976 The hook returns a bitmask of flags that control how the modes in\n\
1977 @var{modes} are used. The flags are:\n\
1978 @table @code\n\
1979 @item VECT_COMPARE_COSTS\n\
1980 Tells the loop vectorizer to try all the provided modes and pick the one\n\
1981 with the lowest cost. By default the vectorizer will choose the first\n\
1982 mode that works.\n\
1983 @end table\n\
1985 The hook does not need to do anything if the vector returned by\n\
1986 @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE} is the only one relevant\n\
1987 for autovectorization. The default implementation adds no modes and\n\
1988 returns 0.",
1989 unsigned int,
1990 (vector_modes *modes, bool all),
1991 default_autovectorize_vector_modes)
1993 DEFHOOK
1994 (related_mode,
1995 "If a piece of code is using vector mode @var{vector_mode} and also wants\n\
1996 to operate on elements of mode @var{element_mode}, return the vector mode\n\
1997 it should use for those elements. If @var{nunits} is nonzero, ensure that\n\
1998 the mode has exactly @var{nunits} elements, otherwise pick whichever vector\n\
1999 size pairs the most naturally with @var{vector_mode}. Return an empty\n\
2000 @code{opt_machine_mode} if there is no supported vector mode with the\n\
2001 required properties.\n\
2003 There is no prescribed way of handling the case in which @var{nunits}\n\
2004 is zero. One common choice is to pick a vector mode with the same size\n\
2005 as @var{vector_mode}; this is the natural choice if the target has a\n\
2006 fixed vector size. Another option is to choose a vector mode with the\n\
2007 same number of elements as @var{vector_mode}; this is the natural choice\n\
2008 if the target has a fixed number of elements. Alternatively, the hook\n\
2009 might choose a middle ground, such as trying to keep the number of\n\
2010 elements as similar as possible while applying maximum and minimum\n\
2011 vector sizes.\n\
2013 The default implementation uses @code{mode_for_vector} to find the\n\
2014 requested mode, returning a mode with the same size as @var{vector_mode}\n\
2015 when @var{nunits} is zero. This is the correct behavior for most targets.",
2016 opt_machine_mode,
2017 (machine_mode vector_mode, scalar_mode element_mode, poly_uint64 nunits),
2018 default_vectorize_related_mode)
2020 /* Function to get a target mode for a vector mask. */
2021 DEFHOOK
2022 (get_mask_mode,
2023 "Return the mode to use for a vector mask that holds one boolean\n\
2024 result for each element of vector mode @var{mode}. The returned mask mode\n\
2025 can be a vector of integers (class @code{MODE_VECTOR_INT}), a vector of\n\
2026 booleans (class @code{MODE_VECTOR_BOOL}) or a scalar integer (class\n\
2027 @code{MODE_INT}). Return an empty @code{opt_machine_mode} if no such\n\
2028 mask mode exists.\n\
2030 The default implementation returns a @code{MODE_VECTOR_INT} with the\n\
2031 same size and number of elements as @var{mode}, if such a mode exists.",
2032 opt_machine_mode,
2033 (machine_mode mode),
2034 default_get_mask_mode)
2036 /* Function to say whether a masked operation is expensive when the
2037 mask is all zeros. */
2038 DEFHOOK
2039 (empty_mask_is_expensive,
2040 "This hook returns true if masked internal function @var{ifn} (really of\n\
2041 type @code{internal_fn}) should be considered expensive when the mask is\n\
2042 all zeros. GCC can then try to branch around the instruction instead.",
2043 bool,
2044 (unsigned ifn),
2045 default_empty_mask_is_expensive)
2047 /* Target builtin that implements vector gather operation. */
2048 DEFHOOK
2049 (builtin_gather,
2050 "Target builtin that implements vector gather operation. @var{mem_vectype}\n\
2051 is the vector type of the load and @var{index_type} is scalar type of\n\
2052 the index, scaled by @var{scale}.\n\
2053 The default is @code{NULL_TREE} which means to not vectorize gather\n\
2054 loads.",
2055 tree,
2056 (const_tree mem_vectype, const_tree index_type, int scale),
2057 NULL)
2059 /* Target builtin that implements vector scatter operation. */
2060 DEFHOOK
2061 (builtin_scatter,
2062 "Target builtin that implements vector scatter operation. @var{vectype}\n\
2063 is the vector type of the store and @var{index_type} is scalar type of\n\
2064 the index, scaled by @var{scale}.\n\
2065 The default is @code{NULL_TREE} which means to not vectorize scatter\n\
2066 stores.",
2067 tree,
2068 (const_tree vectype, const_tree index_type, int scale),
2069 NULL)
2071 /* Target function to initialize the cost model for a loop or block. */
2072 DEFHOOK
2073 (create_costs,
2074 "This hook should initialize target-specific data structures in preparation\n\
2075 for modeling the costs of vectorizing a loop or basic block. The default\n\
2076 allocates three unsigned integers for accumulating costs for the prologue,\n\
2077 body, and epilogue of the loop or basic block. If @var{loop_info} is\n\
2078 non-NULL, it identifies the loop being vectorized; otherwise a single block\n\
2079 is being vectorized. If @var{costing_for_scalar} is true, it indicates the\n\
2080 current cost model is for the scalar version of a loop or block; otherwise\n\
2081 it is for the vector version.",
2082 class vector_costs *,
2083 (vec_info *vinfo, bool costing_for_scalar),
2084 default_vectorize_create_costs)
2086 HOOK_VECTOR_END (vectorize)
2088 #undef HOOK_PREFIX
2089 #define HOOK_PREFIX "TARGET_"
2091 DEFHOOK
2092 (preferred_else_value,
2093 "This hook returns the target's preferred final argument for a call\n\
2094 to conditional internal function @var{ifn} (really of type\n\
2095 @code{internal_fn}). @var{type} specifies the return type of the\n\
2096 function and @var{ops} are the operands to the conditional operation,\n\
2097 of which there are @var{nops}.\n\
2099 For example, if @var{ifn} is @code{IFN_COND_ADD}, the hook returns\n\
2100 a value of type @var{type} that should be used when @samp{@var{ops}[0]}\n\
2101 and @samp{@var{ops}[1]} are conditionally added together.\n\
2103 This hook is only relevant if the target supports conditional patterns\n\
2104 like @code{cond_add@var{m}}. The default implementation returns a zero\n\
2105 constant of type @var{type}.",
2106 tree,
2107 (unsigned ifn, tree type, unsigned nops, tree *ops),
2108 default_preferred_else_value)
2110 DEFHOOK
2111 (record_offload_symbol,
2112 "Used when offloaded functions are seen in the compilation unit and no named\n\
2113 sections are available. It is called once for each symbol that must be\n\
2114 recorded in the offload function and variable table.",
2115 void, (tree),
2116 hook_void_tree)
2118 DEFHOOKPOD
2119 (absolute_biggest_alignment,
2120 "If defined, this target hook specifies the absolute biggest alignment\n\
2121 that a type or variable can have on this machine, otherwise,\n\
2122 @code{BIGGEST_ALIGNMENT} is used.",
2123 HOST_WIDE_INT, BIGGEST_ALIGNMENT)
2125 /* Allow target specific overriding of option settings after options have
2126 been changed by an attribute or pragma or when it is reset at the
2127 end of the code affected by an attribute or pragma. */
2128 DEFHOOK
2129 (override_options_after_change,
2130 "This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}\n\
2131 but is called when the optimize level is changed via an attribute or\n\
2132 pragma or when it is reset at the end of the code affected by the\n\
2133 attribute or pragma. It is not called at the beginning of compilation\n\
2134 when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these\n\
2135 actions then, you should have @code{TARGET_OPTION_OVERRIDE} call\n\
2136 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.",
2137 void, (void),
2138 hook_void_void)
2140 DEFHOOK
2141 (offload_options,
2142 "Used when writing out the list of options into an LTO file. It should\n\
2143 translate any relevant target-specific options (such as the ABI in use)\n\
2144 into one of the @option{-foffload} options that exist as a common interface\n\
2145 to express such options. It should return a string containing these options,\n\
2146 separated by spaces, which the caller will free.\n",
2147 char *, (void), hook_charptr_void_null)
2149 DEFHOOK_UNDOC
2150 (eh_return_filter_mode,
2151 "Return machine mode for filter value.",
2152 scalar_int_mode, (void),
2153 default_eh_return_filter_mode)
2155 /* Return machine mode for libgcc expanded cmp instructions. */
2156 DEFHOOK
2157 (libgcc_cmp_return_mode,
2158 "This target hook should return the mode to be used for the return value\n\
2159 of compare instructions expanded to libgcc calls. If not defined\n\
2160 @code{word_mode} is returned which is the right choice for a majority of\n\
2161 targets.",
2162 scalar_int_mode, (void),
2163 default_libgcc_cmp_return_mode)
2165 /* Return machine mode for libgcc expanded shift instructions. */
2166 DEFHOOK
2167 (libgcc_shift_count_mode,
2168 "This target hook should return the mode to be used for the shift count operand\n\
2169 of shift instructions expanded to libgcc calls. If not defined\n\
2170 @code{word_mode} is returned which is the right choice for a majority of\n\
2171 targets.",
2172 scalar_int_mode, (void),
2173 default_libgcc_shift_count_mode)
2175 /* Return machine mode to be used for _Unwind_Word type. */
2176 DEFHOOK
2177 (unwind_word_mode,
2178 "Return machine mode to be used for @code{_Unwind_Word} type.\n\
2179 The default is to use @code{word_mode}.",
2180 scalar_int_mode, (void),
2181 default_unwind_word_mode)
2183 /* Given two decls, merge their attributes and return the result. */
2184 DEFHOOK
2185 (merge_decl_attributes,
2186 "Define this target hook if the merging of decl attributes needs special\n\
2187 handling. If defined, the result is a list of the combined\n\
2188 @code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.\n\
2189 @var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of\n\
2190 when this is needed are when one attribute overrides another, or when an\n\
2191 attribute is nullified by a subsequent definition. This function may\n\
2192 call @code{merge_attributes} to handle machine-independent merging.\n\
2194 @findex TARGET_DLLIMPORT_DECL_ATTRIBUTES\n\
2195 If the only target-specific handling you require is @samp{dllimport}\n\
2196 for Microsoft Windows targets, you should define the macro\n\
2197 @code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler\n\
2198 will then define a function called\n\
2199 @code{merge_dllimport_decl_attributes} which can then be defined as\n\
2200 the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also\n\
2201 add @code{handle_dll_attribute} in the attribute table for your port\n\
2202 to perform initial processing of the @samp{dllimport} and\n\
2203 @samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and\n\
2204 @file{i386/i386.cc}, for example.",
2205 tree, (tree olddecl, tree newdecl),
2206 merge_decl_attributes)
2208 /* Given two types, merge their attributes and return the result. */
2209 DEFHOOK
2210 (merge_type_attributes,
2211 "Define this target hook if the merging of type attributes needs special\n\
2212 handling. If defined, the result is a list of the combined\n\
2213 @code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed\n\
2214 that @code{comptypes} has already been called and returned 1. This\n\
2215 function may call @code{merge_attributes} to handle machine-independent\n\
2216 merging.",
2217 tree, (tree type1, tree type2),
2218 merge_type_attributes)
2220 /* Table of machine attributes and functions to handle them.
2221 Ignored if empty. */
2222 DEFHOOKPOD
2223 (attribute_table,
2224 "If defined, this target hook provides an array of\n\
2225 @samp{scoped_attribute_spec}s (defined in @file{attribs.h}) that specify the\n\
2226 machine-specific attributes for this target. The information includes some\n\
2227 of the restrictions on the entities to which these attributes are applied\n\
2228 and the arguments that the attributes take.\n\
2230 In C and C++, these attributes are associated with two syntaxes:\n\
2231 the traditional GNU @code{__attribute__} syntax and the standard\n\
2232 @samp{[[]]} syntax. Attributes that support the GNU syntax must be\n\
2233 placed in the @code{gnu} namespace. Such attributes can then also be\n\
2234 written @samp{[[gnu::@dots{}]]}. Attributes that use only the standard\n\
2235 syntax should be placed in whichever namespace the attribute specification\n\
2236 requires. For example, a target might choose to support vendor-specific\n\
2237 @samp{[[]]} attributes that the vendor places in their own namespace.\n\
2239 Targets that only define attributes in the @code{gnu} namespace\n\
2240 can uase the following shorthand to define the table:\n\
2242 @smallexample\n\
2243 TARGET_GNU_ATTRIBUTES (@var{cpu_attribute_table}, @{\n\
2244 @{ \"@var{attribute1}\", @dots{} @},\n\
2245 @{ \"@var{attribute2}\", @dots{} @},\n\
2246 @dots{},\n\
2247 @{ \"@var{attributen}\", @dots{} @},\n\
2248 @});\n\
2249 @end smallexample",
2250 array_slice<const struct scoped_attribute_specs *const>,)
2252 /* Return true iff attribute NAME expects a plain identifier as its first
2253 argument. */
2254 DEFHOOK
2255 (attribute_takes_identifier_p,
2256 "If defined, this target hook is a function which returns true if the\n\
2257 machine-specific attribute named @var{name} expects an identifier\n\
2258 given as its first argument to be passed on as a plain identifier, not\n\
2259 subjected to name lookup. If this is not defined, the default is\n\
2260 false for all machine-specific attributes.",
2261 bool, (const_tree name),
2262 hook_bool_const_tree_false)
2264 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
2265 one if they are compatible and two if they are nearly compatible
2266 (which causes a warning to be generated). */
2267 DEFHOOK
2268 (comp_type_attributes,
2269 "If defined, this target hook is a function which returns zero if the attributes on\n\
2270 @var{type1} and @var{type2} are incompatible, one if they are compatible,\n\
2271 and two if they are nearly compatible (which causes a warning to be\n\
2272 generated). If this is not defined, machine-specific attributes are\n\
2273 supposed always to be compatible.",
2274 int, (const_tree type1, const_tree type2),
2275 hook_int_const_tree_const_tree_1)
2277 /* Assign default attributes to the newly defined TYPE. */
2278 DEFHOOK
2279 (set_default_type_attributes,
2280 "If defined, this target hook is a function which assigns default attributes to\n\
2281 the newly defined @var{type}.",
2282 void, (tree type),
2283 hook_void_tree)
2285 /* Insert attributes on the newly created DECL. */
2286 DEFHOOK
2287 (insert_attributes,
2288 "Define this target hook if you want to be able to add attributes to a decl\n\
2289 when it is being created. This is normally useful for back ends which\n\
2290 wish to implement a pragma by using the attributes which correspond to\n\
2291 the pragma's effect. The @var{node} argument is the decl which is being\n\
2292 created. The @var{attr_ptr} argument is a pointer to the attribute list\n\
2293 for this decl. The list itself should not be modified, since it may be\n\
2294 shared with other decls, but attributes may be chained on the head of\n\
2295 the list and @code{*@var{attr_ptr}} modified to point to the new\n\
2296 attributes, or a copy of the list may be made if further changes are\n\
2297 needed.",
2298 void, (tree node, tree *attr_ptr),
2299 hook_void_tree_treeptr)
2301 /* Perform additional target-specific processing of generic attributes. */
2302 DEFHOOK
2303 (handle_generic_attribute,
2304 "Define this target hook if you want to be able to perform additional\n\
2305 target-specific processing of an attribute which is handled generically\n\
2306 by a front end. The arguments are the same as those which are passed to\n\
2307 attribute handlers. So far this only affects the @var{noinit} and\n\
2308 @var{section} attribute.",
2309 tree, (tree *node, tree name, tree args, int flags, bool *no_add_attrs),
2310 hook_tree_treeptr_tree_tree_int_boolptr_null)
2312 /* Return true if FNDECL (which has at least one machine attribute)
2313 can be inlined despite its machine attributes, false otherwise. */
2314 DEFHOOK
2315 (function_attribute_inlinable_p,
2316 "@cindex inlining\n\
2317 This target hook returns @code{true} if it is OK to inline @var{fndecl}\n\
2318 into the current function, despite its having target-specific\n\
2319 attributes, @code{false} otherwise. By default, if a function has a\n\
2320 target specific attribute attached to it, it will not be inlined.",
2321 bool, (const_tree fndecl),
2322 hook_bool_const_tree_false)
2324 /* Return true if bitfields in RECORD_TYPE should follow the
2325 Microsoft Visual C++ bitfield layout rules. */
2326 DEFHOOK
2327 (ms_bitfield_layout_p,
2328 "This target hook returns @code{true} if bit-fields in the given\n\
2329 @var{record_type} are to be laid out following the rules of Microsoft\n\
2330 Visual C/C++, namely: (i) a bit-field won't share the same storage\n\
2331 unit with the previous bit-field if their underlying types have\n\
2332 different sizes, and the bit-field will be aligned to the highest\n\
2333 alignment of the underlying types of itself and of the previous\n\
2334 bit-field; (ii) a zero-sized bit-field will affect the alignment of\n\
2335 the whole enclosing structure, even if it is unnamed; except that\n\
2336 (iii) a zero-sized bit-field will be disregarded unless it follows\n\
2337 another bit-field of nonzero size. If this hook returns @code{true},\n\
2338 other macros that control bit-field layout are ignored.\n\
2340 When a bit-field is inserted into a packed record, the whole size\n\
2341 of the underlying type is used by one or more same-size adjacent\n\
2342 bit-fields (that is, if its long:3, 32 bits is used in the record,\n\
2343 and any additional adjacent long bit-fields are packed into the same\n\
2344 chunk of 32 bits. However, if the size changes, a new field of that\n\
2345 size is allocated). In an unpacked record, this is the same as using\n\
2346 alignment, but not equivalent when packing.\n\
2348 If both MS bit-fields and @samp{__attribute__((packed))} are used,\n\
2349 the latter will take precedence. If @samp{__attribute__((packed))} is\n\
2350 used on a single field when MS bit-fields are in use, it will take\n\
2351 precedence for that field, but the alignment of the rest of the structure\n\
2352 may affect its placement.",
2353 bool, (const_tree record_type),
2354 hook_bool_const_tree_false)
2356 /* For now this is only an interface to WORDS_BIG_ENDIAN for
2357 target-independent code like the front ends, need performance testing
2358 before switching completely to the target hook. */
2359 DEFHOOK_UNDOC
2360 (words_big_endian,
2362 bool, (void),
2363 targhook_words_big_endian)
2365 /* Likewise for FLOAT_WORDS_BIG_ENDIAN. */
2366 DEFHOOK_UNDOC
2367 (float_words_big_endian,
2369 bool, (void),
2370 targhook_float_words_big_endian)
2372 DEFHOOK
2373 (float_exceptions_rounding_supported_p,
2374 "Returns true if the target supports IEEE 754 floating-point exceptions\n\
2375 and rounding modes, false otherwise. This is intended to relate to the\n\
2376 @code{float} and @code{double} types, but not necessarily @code{long double}.\n\
2377 By default, returns true if the @code{adddf3} instruction pattern is\n\
2378 available and false otherwise, on the assumption that hardware floating\n\
2379 point supports exceptions and rounding modes but software floating point\n\
2380 does not.",
2381 bool, (void),
2382 default_float_exceptions_rounding_supported_p)
2384 /* True if the target supports decimal floating point. */
2385 DEFHOOK
2386 (decimal_float_supported_p,
2387 "Returns true if the target supports decimal floating point.",
2388 bool, (void),
2389 default_decimal_float_supported_p)
2391 /* True if the target supports fixed-point. */
2392 DEFHOOK
2393 (fixed_point_supported_p,
2394 "Returns true if the target supports fixed-point arithmetic.",
2395 bool, (void),
2396 default_fixed_point_supported_p)
2398 /* Return true if anonymous bitfields affect structure alignment. */
2399 DEFHOOK
2400 (align_anon_bitfield,
2401 "When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine\n\
2402 whether unnamed bitfields affect the alignment of the containing\n\
2403 structure. The hook should return true if the structure should inherit\n\
2404 the alignment requirements of an unnamed bitfield's type.",
2405 bool, (void),
2406 hook_bool_void_false)
2408 /* Return true if volatile bitfields should use the narrowest type possible.
2409 Return false if they should use the container type. */
2410 DEFHOOK
2411 (narrow_volatile_bitfield,
2412 "This target hook should return @code{true} if accesses to volatile bitfields\n\
2413 should use the narrowest mode possible. It should return @code{false} if\n\
2414 these accesses should use the bitfield container type.\n\
2416 The default is @code{false}.",
2417 bool, (void),
2418 hook_bool_void_false)
2420 /* Set up target-specific built-in functions. */
2421 DEFHOOK
2422 (init_builtins,
2423 "Define this hook if you have any machine-specific built-in functions\n\
2424 that need to be defined. It should be a function that performs the\n\
2425 necessary setup.\n\
2427 Machine specific built-in functions can be useful to expand special machine\n\
2428 instructions that would otherwise not normally be generated because\n\
2429 they have no equivalent in the source language (for example, SIMD vector\n\
2430 instructions or prefetch instructions).\n\
2432 To create a built-in function, call the function\n\
2433 @code{lang_hooks.builtin_function}\n\
2434 which is defined by the language front end. You can use any type nodes set\n\
2435 up by @code{build_common_tree_nodes};\n\
2436 only language front ends that use those two functions will call\n\
2437 @samp{TARGET_INIT_BUILTINS}.",
2438 void, (void),
2439 hook_void_void)
2441 /* Initialize (if INITIALIZE_P is true) and return the target-specific
2442 built-in function decl for CODE.
2443 Return NULL if that is not possible. Return error_mark_node if CODE
2444 is outside of the range of valid target builtin function codes. */
2445 DEFHOOK
2446 (builtin_decl,
2447 "Define this hook if you have any machine-specific built-in functions\n\
2448 that need to be defined. It should be a function that returns the\n\
2449 builtin function declaration for the builtin function code @var{code}.\n\
2450 If there is no such builtin and it cannot be initialized at this time\n\
2451 if @var{initialize_p} is true the function should return @code{NULL_TREE}.\n\
2452 If @var{code} is out of range the function should return\n\
2453 @code{error_mark_node}.",
2454 tree, (unsigned code, bool initialize_p), NULL)
2456 /* Expand a target-specific builtin. */
2457 DEFHOOK
2458 (expand_builtin,
2459 "\n\
2460 Expand a call to a machine specific built-in function that was set up by\n\
2461 @samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the\n\
2462 function call; the result should go to @var{target} if that is\n\
2463 convenient, and have mode @var{mode} if that is convenient.\n\
2464 @var{subtarget} may be used as the target for computing one of\n\
2465 @var{exp}'s operands. @var{ignore} is nonzero if the value is to be\n\
2466 ignored. This function should return the result of the call to the\n\
2467 built-in function.",
2468 rtx,
2469 (tree exp, rtx target, rtx subtarget, machine_mode mode, int ignore),
2470 default_expand_builtin)
2472 /* Select a replacement for a target-specific builtin. This is done
2473 *before* regular type checking, and so allows the target to
2474 implement a crude form of function overloading. The result is a
2475 complete expression that implements the operation. PARAMS really
2476 has type VEC(tree,gc)*, but we don't want to include tree.h here. */
2477 DEFHOOK
2478 (resolve_overloaded_builtin,
2479 "Select a replacement for a machine specific built-in function that\n\
2480 was set up by @samp{TARGET_INIT_BUILTINS}. This is done\n\
2481 @emph{before} regular type checking, and so allows the target to\n\
2482 implement a crude form of function overloading. @var{fndecl} is the\n\
2483 declaration of the built-in function. @var{arglist} is the list of\n\
2484 arguments passed to the built-in function. The result is a\n\
2485 complete expression that implements the operation, usually\n\
2486 another @code{CALL_EXPR}.\n\
2487 @var{arglist} really has type @samp{VEC(tree,gc)*}",
2488 tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
2490 DEFHOOK
2491 (check_builtin_call,
2492 "Perform semantic checking on a call to a machine-specific built-in\n\
2493 function after its arguments have been constrained to the function\n\
2494 signature. Return true if the call is valid, otherwise report an error\n\
2495 and return false.\n\
2497 This hook is called after @code{TARGET_RESOLVE_OVERLOADED_BUILTIN}.\n\
2498 The call was originally to built-in function @var{orig_fndecl},\n\
2499 but after the optional @code{TARGET_RESOLVE_OVERLOADED_BUILTIN}\n\
2500 step is now to built-in function @var{fndecl}. @var{loc} is the\n\
2501 location of the call and @var{args} is an array of function arguments,\n\
2502 of which there are @var{nargs}. @var{arg_loc} specifies the location\n\
2503 of each argument.",
2504 bool, (location_t loc, vec<location_t> arg_loc, tree fndecl,
2505 tree orig_fndecl, unsigned int nargs, tree *args),
2506 NULL)
2508 /* Fold a target-specific builtin to a tree valid for both GIMPLE
2509 and GENERIC. */
2510 DEFHOOK
2511 (fold_builtin,
2512 "Fold a call to a machine specific built-in function that was set up by\n\
2513 @samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the\n\
2514 built-in function. @var{n_args} is the number of arguments passed to\n\
2515 the function; the arguments themselves are pointed to by @var{argp}.\n\
2516 The result is another tree, valid for both GIMPLE and GENERIC,\n\
2517 containing a simplified expression for the call's result. If\n\
2518 @var{ignore} is true the value will be ignored.",
2519 tree, (tree fndecl, int n_args, tree *argp, bool ignore),
2520 hook_tree_tree_int_treep_bool_null)
2522 /* Fold a target-specific builtin to a valid GIMPLE tree. */
2523 DEFHOOK
2524 (gimple_fold_builtin,
2525 "Fold a call to a machine specific built-in function that was set up\n\
2526 by @samp{TARGET_INIT_BUILTINS}. @var{gsi} points to the gimple\n\
2527 statement holding the function call. Returns true if any change\n\
2528 was made to the GIMPLE stream.",
2529 bool, (gimple_stmt_iterator *gsi),
2530 hook_bool_gsiptr_false)
2532 /* Target hook is used to compare the target attributes in two functions to
2533 determine which function's features get higher priority. This is used
2534 during function multi-versioning to figure out the order in which two
2535 versions must be dispatched. A function version with a higher priority
2536 is checked for dispatching earlier. DECL1 and DECL2 are
2537 the two function decls that will be compared. It returns positive value
2538 if DECL1 is higher priority, negative value if DECL2 is higher priority
2539 and 0 if they are the same. */
2540 DEFHOOK
2541 (compare_version_priority,
2542 "This hook is used to compare the target attributes in two functions to\n\
2543 determine which function's features get higher priority. This is used\n\
2544 during function multi-versioning to figure out the order in which two\n\
2545 versions must be dispatched. A function version with a higher priority\n\
2546 is checked for dispatching earlier. @var{decl1} and @var{decl2} are\n\
2547 the two function decls that will be compared.",
2548 int, (tree decl1, tree decl2), NULL)
2550 /* Target hook is used to generate the dispatcher logic to invoke the right
2551 function version at run-time for a given set of function versions.
2552 ARG points to the callgraph node of the dispatcher function whose body
2553 must be generated. */
2554 DEFHOOK
2555 (generate_version_dispatcher_body,
2556 "This hook is used to generate the dispatcher logic to invoke the right\n\
2557 function version at run-time for a given set of function versions.\n\
2558 @var{arg} points to the callgraph node of the dispatcher function whose\n\
2559 body must be generated.",
2560 tree, (void *arg), NULL)
2562 /* Target hook is used to get the dispatcher function for a set of function
2563 versions. The dispatcher function is called to invoke the right function
2564 version at run-time. DECL is one version from a set of semantically
2565 identical versions. */
2566 DEFHOOK
2567 (get_function_versions_dispatcher,
2568 "This hook is used to get the dispatcher function for a set of function\n\
2569 versions. The dispatcher function is called to invoke the right function\n\
2570 version at run-time. @var{decl} is one version from a set of semantically\n\
2571 identical versions.",
2572 tree, (void *decl), NULL)
2574 /* Returns a code for a target-specific builtin that implements
2575 reciprocal of a target-specific function, or NULL_TREE if not available. */
2576 DEFHOOK
2577 (builtin_reciprocal,
2578 "This hook should return the DECL of a function that implements the\n\
2579 reciprocal of the machine-specific builtin function @var{fndecl}, or\n\
2580 @code{NULL_TREE} if such a function is not available.",
2581 tree, (tree fndecl),
2582 default_builtin_reciprocal)
2584 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
2585 string containing the C++ mangling for TYPE. In all other cases, return
2586 NULL. */
2587 DEFHOOK
2588 (mangle_type,
2589 "If your target defines any fundamental types, or any types your target\n\
2590 uses should be mangled differently from the default, define this hook\n\
2591 to return the appropriate encoding for these types as part of a C++\n\
2592 mangled name. The @var{type} argument is the tree structure representing\n\
2593 the type to be mangled. The hook may be applied to trees which are\n\
2594 not target-specific fundamental types; it should return @code{NULL}\n\
2595 for all such types, as well as arguments it does not recognize. If the\n\
2596 return value is not @code{NULL}, it must point to a statically-allocated\n\
2597 string constant.\n\
2599 Target-specific fundamental types might be new fundamental types or\n\
2600 qualified versions of ordinary fundamental types. Encode new\n\
2601 fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}\n\
2602 is the name used for the type in source code, and @var{n} is the\n\
2603 length of @var{name} in decimal. Encode qualified versions of\n\
2604 ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where\n\
2605 @var{name} is the name used for the type qualifier in source code,\n\
2606 @var{n} is the length of @var{name} as above, and @var{code} is the\n\
2607 code used to represent the unqualified version of this type. (See\n\
2608 @code{write_builtin_type} in @file{cp/mangle.cc} for the list of\n\
2609 codes.) In both cases the spaces are for clarity; do not include any\n\
2610 spaces in your string.\n\
2612 This hook is applied to types prior to typedef resolution. If the mangled\n\
2613 name for a particular type depends only on that type's main variant, you\n\
2614 can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}\n\
2615 before mangling.\n\
2617 The default version of this hook always returns @code{NULL}, which is\n\
2618 appropriate for a target that does not define any new fundamental\n\
2619 types.",
2620 const char *, (const_tree type),
2621 hook_constcharptr_const_tree_null)
2623 /* Temporarily add conditional target specific types for the purpose of
2624 emitting C++ fundamental type tinfos. */
2625 DEFHOOK
2626 (emit_support_tinfos,
2627 "If your target defines any fundamental types which depend on ISA flags,\n\
2628 they might need C++ tinfo symbols in libsupc++/libstdc++ regardless of\n\
2629 ISA flags the library is compiled with.\n\
2630 This hook allows creating tinfo symbols even for those cases, by temporarily\n\
2631 creating each corresponding fundamental type trees, calling the\n\
2632 @var{callback} function on it and setting the type back to @code{nullptr}.",
2633 void, (emit_support_tinfos_callback callback),
2634 default_emit_support_tinfos)
2636 /* Make any adjustments to libfunc names needed for this target. */
2637 DEFHOOK
2638 (init_libfuncs,
2639 "This hook should declare additional library routines or rename\n\
2640 existing ones, using the functions @code{set_optab_libfunc} and\n\
2641 @code{init_one_libfunc} defined in @file{optabs.cc}.\n\
2642 @code{init_optabs} calls this macro after initializing all the normal\n\
2643 library routines.\n\
2645 The default is to do nothing. Most ports don't need to define this hook.",
2646 void, (void),
2647 hook_void_void)
2649 /* Add a __gnu_ prefix to library functions rather than just __. */
2650 DEFHOOKPOD
2651 (libfunc_gnu_prefix,
2652 "If false (the default), internal library routines start with two\n\
2653 underscores. If set to true, these routines start with @code{__gnu_}\n\
2654 instead. E.g., @code{__muldi3} changes to @code{__gnu_muldi3}. This\n\
2655 currently only affects functions defined in @file{libgcc2.c}. If this\n\
2656 is set to true, the @file{tm.h} file must also\n\
2657 @code{#define LIBGCC2_GNU_PREFIX}.",
2658 bool, false)
2660 /* Given a decl, a section name, and whether the decl initializer
2661 has relocs, choose attributes for the section. */
2662 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
2663 DEFHOOK
2664 (section_type_flags,
2665 "Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}\n\
2666 based on a variable or function decl, a section name, and whether or not the\n\
2667 declaration's initializer may contain runtime relocations. @var{decl} may be\n\
2668 null, in which case read-write data should be assumed.\n\
2670 The default version of this function handles choosing code vs data,\n\
2671 read-only vs read-write data, and @code{flag_pic}. You should only\n\
2672 need to override this if your target has special flags that might be\n\
2673 set via @code{__attribute__}.",
2674 unsigned int, (tree decl, const char *name, int reloc),
2675 default_section_type_flags)
2677 DEFHOOK
2678 (libc_has_function,
2679 "This hook determines whether a function from a class of functions\n\
2680 @var{fn_class} is present in the target C library. If @var{type} is NULL,\n\
2681 the caller asks for support for all standard (float, double, long double)\n\
2682 types. If @var{type} is non-NULL, the caller asks for support for a\n\
2683 specific type.",
2684 bool, (enum function_class fn_class, tree type),
2685 default_libc_has_function)
2687 DEFHOOK
2688 (libc_has_fast_function,
2689 "This hook determines whether a function from a class of functions\n\
2690 @code{(enum function_class)}@var{fcode} has a fast implementation.",
2691 bool, (int fcode),
2692 default_libc_has_fast_function)
2694 DEFHOOK
2695 (fortify_source_default_level,
2696 "This hook determines what value _FORTIFY_SOURCE will be set to when using\n\
2697 the command-line option -fhardened.",
2698 unsigned, (void),
2699 default_fortify_source_default_level)
2701 DEFHOOK
2702 (libm_function_max_error,
2703 "This hook determines expected maximum errors for math functions measured\n\
2704 in ulps (units of the last place). 0 means 0.5ulps precision (correctly\n\
2705 rounded). ~0U means unknown errors. The @code{combined_fn} @var{cfn}\n\
2706 argument should identify just which math built-in function it is rather than\n\
2707 its variant, @var{mode} the variant in terms of floating-point machine mode.\n\
2708 The hook should also take into account @code{flag_rounding_math} whether it\n\
2709 is maximum error just in default rounding mode, or in all possible rounding\n\
2710 modes. @var{boundary_p} is @code{true} for maximum errors on intrinsic math\n\
2711 boundaries of functions rather than errors inside of the usual result ranges\n\
2712 of the functions. E.g.@ the sin/cos function finite result is in between\n\
2713 -1.0 and 1.0 inclusive, with @var{boundary_p} true the function returns how\n\
2714 many ulps below or above those boundaries result could be.",
2715 unsigned, (unsigned cfn, machine_mode mode, bool boundary_p),
2716 default_libm_function_max_error)
2718 /* True if new jumps cannot be created, to replace existing ones or
2719 not, at the current point in the compilation. */
2720 DEFHOOK
2721 (cannot_modify_jumps_p,
2722 "This target hook returns @code{true} past the point in which new jump\n\
2723 instructions could be created. On machines that require a register for\n\
2724 every jump such as the SHmedia ISA of SH5, this point would typically be\n\
2725 reload, so this target hook should be defined to a function such as:\n\
2727 @smallexample\n\
2728 static bool\n\
2729 cannot_modify_jumps_past_reload_p ()\n\
2730 @{\n\
2731 return (reload_completed || reload_in_progress);\n\
2732 @}\n\
2733 @end smallexample",
2734 bool, (void),
2735 hook_bool_void_false)
2737 /* True if FOLLOWER may be modified to follow FOLLOWEE. */
2738 DEFHOOK
2739 (can_follow_jump,
2740 "FOLLOWER and FOLLOWEE are JUMP_INSN instructions;\n\
2741 return true if FOLLOWER may be modified to follow FOLLOWEE;\n\
2742 false, if it can't.\n\
2743 For example, on some targets, certain kinds of branches can't be made to\n\
2744 follow through a hot/cold partitioning.",
2745 bool, (const rtx_insn *follower, const rtx_insn *followee),
2746 hook_bool_const_rtx_insn_const_rtx_insn_true)
2748 /* Return true if the target supports conditional execution. */
2749 DEFHOOK
2750 (have_conditional_execution,
2751 "This target hook returns true if the target supports conditional execution.\n\
2752 This target hook is required only when the target has several different\n\
2753 modes and they have different conditional execution capability, such as ARM.",
2754 bool, (void),
2755 default_have_conditional_execution)
2757 DEFHOOK
2758 (gen_ccmp_first,
2759 "This function prepares to emit a comparison insn for the first compare in a\n\
2760 sequence of conditional comparisions. It returns an appropriate comparison\n\
2761 with @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2762 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2763 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2764 compares in the conditional comparision are generated without error.\n\
2765 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.",
2766 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, rtx_code code, tree op0, tree op1),
2767 NULL)
2769 DEFHOOK
2770 (gen_ccmp_next,
2771 "This function prepares to emit a conditional comparison within a sequence\n\
2772 of conditional comparisons. It returns an appropriate comparison with\n\
2773 @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2774 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2775 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2776 compares in the conditional comparision are generated without error. The\n\
2777 @var{prev} expression is the result of a prior call to @code{gen_ccmp_first}\n\
2778 or @code{gen_ccmp_next}. It may return @code{NULL} if the combination of\n\
2779 @var{prev} and this comparison is not supported, otherwise the result must\n\
2780 be appropriate for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2781 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.\n\
2782 @var{bit_code} is @code{AND} or @code{IOR}, which is the op on the compares.",
2783 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, rtx prev, rtx_code cmp_code, tree op0, tree op1, rtx_code bit_code),
2784 NULL)
2786 /* Return a new value for loop unroll size. */
2787 DEFHOOK
2788 (loop_unroll_adjust,
2789 "This target hook returns a new value for the number of times @var{loop}\n\
2790 should be unrolled. The parameter @var{nunroll} is the number of times\n\
2791 the loop is to be unrolled. The parameter @var{loop} is a pointer to\n\
2792 the loop, which is going to be checked for unrolling. This target hook\n\
2793 is required only when the target has special constraints like maximum\n\
2794 number of memory accesses.",
2795 unsigned, (unsigned nunroll, class loop *loop),
2796 NULL)
2798 /* True if X is a legitimate MODE-mode immediate operand. */
2799 DEFHOOK
2800 (legitimate_constant_p,
2801 "This hook returns true if @var{x} is a legitimate constant for a\n\
2802 @var{mode}-mode immediate operand on the target machine. You can assume that\n\
2803 @var{x} satisfies @code{CONSTANT_P}, so you need not check this.\n\
2805 The default definition returns true.",
2806 bool, (machine_mode mode, rtx x),
2807 hook_bool_mode_rtx_true)
2809 /* True if X is a TLS operand whose value should be pre-computed. */
2810 DEFHOOK
2811 (precompute_tls_p,
2812 "This hook returns true if @var{x} is a TLS operand on the target\n\
2813 machine that should be pre-computed when used as the argument in a call.\n\
2814 You can assume that @var{x} satisfies @code{CONSTANT_P}, so you need not \n\
2815 check this.\n\
2817 The default definition returns false.",
2818 bool, (machine_mode mode, rtx x),
2819 hook_bool_mode_rtx_false)
2821 /* True if the constant X cannot be placed in the constant pool. */
2822 DEFHOOK
2823 (cannot_force_const_mem,
2824 "This hook should return true if @var{x} is of a form that cannot (or\n\
2825 should not) be spilled to the constant pool. @var{mode} is the mode\n\
2826 of @var{x}.\n\
2828 The default version of this hook returns false.\n\
2830 The primary reason to define this hook is to prevent reload from\n\
2831 deciding that a non-legitimate constant would be better reloaded\n\
2832 from the constant pool instead of spilling and reloading a register\n\
2833 holding the constant. This restriction is often true of addresses\n\
2834 of TLS symbols for various targets.",
2835 bool, (machine_mode mode, rtx x),
2836 hook_bool_mode_rtx_false)
2838 DEFHOOK_UNDOC
2839 (cannot_copy_insn_p,
2840 "True if the insn @var{x} cannot be duplicated.",
2841 bool, (rtx_insn *), NULL)
2843 /* True if X is considered to be commutative. */
2844 DEFHOOK
2845 (commutative_p,
2846 "This target hook returns @code{true} if @var{x} is considered to be commutative.\n\
2847 Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider\n\
2848 PLUS to be commutative inside a MEM@. @var{outer_code} is the rtx code\n\
2849 of the enclosing rtl, if known, otherwise it is UNKNOWN.",
2850 bool, (const_rtx x, int outer_code),
2851 hook_bool_const_rtx_commutative_p)
2853 /* True if ADDR is an address-expression whose effect depends
2854 on the mode of the memory reference it is used in. */
2855 DEFHOOK
2856 (mode_dependent_address_p,
2857 "This hook returns @code{true} if memory address @var{addr} in address\n\
2858 space @var{addrspace} can have\n\
2859 different meanings depending on the machine mode of the memory\n\
2860 reference it is used for or if the address is valid for some modes\n\
2861 but not others.\n\
2863 Autoincrement and autodecrement addresses typically have mode-dependent\n\
2864 effects because the amount of the increment or decrement is the size\n\
2865 of the operand being addressed. Some machines have other mode-dependent\n\
2866 addresses. Many RISC machines have no mode-dependent addresses.\n\
2868 You may assume that @var{addr} is a valid address for the machine.\n\
2870 The default version of this hook returns @code{false}.",
2871 bool, (const_rtx addr, addr_space_t addrspace),
2872 default_mode_dependent_address_p)
2874 /* Given an invalid address X for a given machine mode, try machine-specific
2875 ways to make it legitimate. Return X or an invalid address on failure. */
2876 DEFHOOK
2877 (legitimize_address,
2878 "This hook is given an invalid memory address @var{x} for an\n\
2879 operand of mode @var{mode} and should try to return a valid memory\n\
2880 address.\n\
2882 @findex break_out_memory_refs\n\
2883 @var{x} will always be the result of a call to @code{break_out_memory_refs},\n\
2884 and @var{oldx} will be the operand that was given to that function to produce\n\
2885 @var{x}.\n\
2887 The code of the hook should not alter the substructure of\n\
2888 @var{x}. If it transforms @var{x} into a more legitimate form, it\n\
2889 should return the new @var{x}.\n\
2891 It is not necessary for this hook to come up with a legitimate address,\n\
2892 with the exception of native TLS addresses (@pxref{Emulated TLS}).\n\
2893 The compiler has standard ways of doing so in all cases. In fact, if\n\
2894 the target supports only emulated TLS, it\n\
2895 is safe to omit this hook or make it return @var{x} if it cannot find\n\
2896 a valid way to legitimize the address. But often a machine-dependent\n\
2897 strategy can generate better code.",
2898 rtx, (rtx x, rtx oldx, machine_mode mode),
2899 default_legitimize_address)
2901 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
2902 DEFHOOK
2903 (delegitimize_address,
2904 "This hook is used to undo the possibly obfuscating effects of the\n\
2905 @code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target\n\
2906 macros. Some backend implementations of these macros wrap symbol\n\
2907 references inside an @code{UNSPEC} rtx to represent PIC or similar\n\
2908 addressing modes. This target hook allows GCC's optimizers to understand\n\
2909 the semantics of these opaque @code{UNSPEC}s by converting them back\n\
2910 into their original form.",
2911 rtx, (rtx x),
2912 delegitimize_mem_from_attrs)
2914 /* Given an RTX, return true if it is not ok to emit it into debug info
2915 section. */
2916 DEFHOOK
2917 (const_not_ok_for_debug_p,
2918 "This hook should return true if @var{x} should not be emitted into\n\
2919 debug sections.",
2920 bool, (rtx x),
2921 default_const_not_ok_for_debug_p)
2923 /* Given an address RTX, say whether it is valid. */
2924 DEFHOOK
2925 (legitimate_address_p,
2926 "A function that returns whether @var{x} (an RTX) is a legitimate memory\n\
2927 address on the target machine for a memory operand of mode @var{mode}.\n\
2928 If @var{ch} is not @code{ERROR_MARK}, it can be called from middle-end to\n\
2929 determine if it is valid to use @var{x} as a memory operand for RTX insn\n\
2930 which is generated for the given code_helper @var{ch}. For example,\n\
2931 assuming the given @var{ch} is IFN_LEN_LOAD, on some target its underlying\n\
2932 hardware instructions support fewer addressing modes than what are for the\n\
2933 normal vector load and store, then with this @var{ch} target can know the\n\
2934 actual use context and return more exact result.\n\
2936 Legitimate addresses are defined in two variants: a strict variant and a\n\
2937 non-strict one. The @var{strict} parameter chooses which variant is\n\
2938 desired by the caller.\n\
2940 The strict variant is used in the reload pass. It must be defined so\n\
2941 that any pseudo-register that has not been allocated a hard register is\n\
2942 considered a memory reference. This is because in contexts where some\n\
2943 kind of register is required, a pseudo-register with no hard register\n\
2944 must be rejected. For non-hard registers, the strict variant should look\n\
2945 up the @code{reg_renumber} array; it should then proceed using the hard\n\
2946 register number in the array, or treat the pseudo as a memory reference\n\
2947 if the array holds @code{-1}.\n\
2949 The non-strict variant is used in other passes. It must be defined to\n\
2950 accept all pseudo-registers in every context where some kind of\n\
2951 register is required.\n\
2953 Normally, constant addresses which are the sum of a @code{symbol_ref}\n\
2954 and an integer are stored inside a @code{const} RTX to mark them as\n\
2955 constant. Therefore, there is no need to recognize such sums\n\
2956 specifically as legitimate addresses. Normally you would simply\n\
2957 recognize any @code{const} as legitimate.\n\
2959 Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant\n\
2960 sums that are not marked with @code{const}. It assumes that a naked\n\
2961 @code{plus} indicates indexing. If so, then you @emph{must} reject such\n\
2962 naked constant sums as illegitimate addresses, so that none of them will\n\
2963 be given to @code{PRINT_OPERAND_ADDRESS}.\n\
2965 @cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation\n\
2966 On some machines, whether a symbolic address is legitimate depends on\n\
2967 the section that the address refers to. On these machines, define the\n\
2968 target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information\n\
2969 into the @code{symbol_ref}, and then check for it here. When you see a\n\
2970 @code{const}, you will have to look inside it to find the\n\
2971 @code{symbol_ref} in order to determine the section. @xref{Assembler\n\
2972 Format}.\n\
2974 @cindex @code{GO_IF_LEGITIMATE_ADDRESS}\n\
2975 Some ports are still using a deprecated legacy substitute for\n\
2976 this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro. This macro\n\
2977 has this syntax:\n\
2979 @example\n\
2980 #define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})\n\
2981 @end example\n\
2983 @noindent\n\
2984 and should @code{goto @var{label}} if the address @var{x} is a valid\n\
2985 address on the target machine for a memory operand of mode @var{mode}.\n\
2987 @findex REG_OK_STRICT\n\
2988 Compiler source files that want to use the strict variant of this\n\
2989 macro define the macro @code{REG_OK_STRICT}. You should use an\n\
2990 @code{#ifdef REG_OK_STRICT} conditional to define the strict variant in\n\
2991 that case and the non-strict variant otherwise.\n\
2993 Using the hook is usually simpler because it limits the number of\n\
2994 files that are recompiled when changes are made.",
2995 bool, (machine_mode mode, rtx x, bool strict, code_helper ch),
2996 default_legitimate_address_p)
2998 /* True if the given constant can be put into an object_block. */
2999 DEFHOOK
3000 (use_blocks_for_constant_p,
3001 "This hook should return true if pool entries for constant @var{x} can\n\
3002 be placed in an @code{object_block} structure. @var{mode} is the mode\n\
3003 of @var{x}.\n\
3005 The default version returns false for all constants.",
3006 bool, (machine_mode mode, const_rtx x),
3007 hook_bool_mode_const_rtx_false)
3009 /* True if the given decl can be put into an object_block. */
3010 DEFHOOK
3011 (use_blocks_for_decl_p,
3012 "This hook should return true if pool entries for @var{decl} should\n\
3013 be placed in an @code{object_block} structure.\n\
3015 The default version returns true for all decls.",
3016 bool, (const_tree decl),
3017 hook_bool_const_tree_true)
3019 /* The minimum and maximum byte offsets for anchored addresses. */
3020 DEFHOOKPOD
3021 (min_anchor_offset,
3022 "The minimum offset that should be applied to a section anchor.\n\
3023 On most targets, it should be the smallest offset that can be\n\
3024 applied to a base register while still giving a legitimate address\n\
3025 for every mode. The default value is 0.",
3026 HOST_WIDE_INT, 0)
3028 DEFHOOKPOD
3029 (max_anchor_offset,
3030 "Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)\n\
3031 offset that should be applied to section anchors. The default\n\
3032 value is 0.",
3033 HOST_WIDE_INT, 0)
3035 /* True if section anchors can be used to access the given symbol. */
3036 DEFHOOK
3037 (use_anchors_for_symbol_p,
3038 "Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}\n\
3039 @var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and\n\
3040 @samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.\n\
3042 The default version is correct for most targets, but you might need to\n\
3043 intercept this hook to handle things like target-specific attributes\n\
3044 or target-specific sections.",
3045 bool, (const_rtx x),
3046 default_use_anchors_for_symbol_p)
3048 /* True if target supports indirect functions. */
3049 DEFHOOK
3050 (has_ifunc_p,
3051 "It returns true if the target supports GNU indirect functions.\n\
3052 The support includes the assembler, linker and dynamic linker.\n\
3053 The default value of this hook is based on target's libc.",
3054 bool, (void),
3055 default_has_ifunc_p)
3057 /* True if it is OK to reference indirect function resolvers locally. */
3058 DEFHOOK
3059 (ifunc_ref_local_ok,
3060 "Return true if it is OK to reference indirect function resolvers\n\
3061 locally. The default is to return false.",
3062 bool, (void),
3063 hook_bool_void_false)
3065 /* True if it is OK to do sibling call optimization for the specified
3066 call expression EXP. DECL will be the called function, or NULL if
3067 this is an indirect call. */
3068 DEFHOOK
3069 (function_ok_for_sibcall,
3070 "True if it is OK to do sibling call optimization for the specified\n\
3071 call expression @var{exp}. @var{decl} will be the called function,\n\
3072 or @code{NULL} if this is an indirect call.\n\
3074 It is not uncommon for limitations of calling conventions to prevent\n\
3075 tail calls to functions outside the current unit of translation, or\n\
3076 during PIC compilation. The hook is used to enforce these restrictions,\n\
3077 as the @code{sibcall} md pattern cannot fail, or fall over to a\n\
3078 ``normal'' call. The criteria for successful sibling call optimization\n\
3079 may vary greatly between different architectures.",
3080 bool, (tree decl, tree exp),
3081 hook_bool_tree_tree_false)
3083 /* Establish appropriate back-end context for processing the function
3084 FNDECL. The argument might be NULL to indicate processing at top
3085 level, outside of any function scope. */
3086 DEFHOOK
3087 (set_current_function,
3088 "The compiler invokes this hook whenever it changes its current function\n\
3089 context (@code{cfun}). You can define this function if\n\
3090 the back end needs to perform any initialization or reset actions on a\n\
3091 per-function basis. For example, it may be used to implement function\n\
3092 attributes that affect register usage or code generation patterns.\n\
3093 The argument @var{decl} is the declaration for the new function context,\n\
3094 and may be null to indicate that the compiler has left a function context\n\
3095 and is returning to processing at the top level.\n\
3096 The default hook function does nothing.\n\
3098 GCC sets @code{cfun} to a dummy function context during initialization of\n\
3099 some parts of the back end. The hook function is not invoked in this\n\
3100 situation; you need not worry about the hook being invoked recursively,\n\
3101 or when the back end is in a partially-initialized state.\n\
3102 @code{cfun} might be @code{NULL} to indicate processing at top level,\n\
3103 outside of any function scope.",
3104 void, (tree decl), hook_void_tree)
3106 /* True if EXP should be placed in a "small data" section. */
3107 DEFHOOK
3108 (in_small_data_p,
3109 "Returns true if @var{exp} should be placed into a ``small data'' section.\n\
3110 The default version of this hook always returns false.",
3111 bool, (const_tree exp),
3112 hook_bool_const_tree_false)
3114 /* True if EXP names an object for which name resolution must resolve
3115 to the current executable or shared library. */
3116 DEFHOOK
3117 (binds_local_p,
3118 "Returns true if @var{exp} names an object for which name resolution\n\
3119 rules must resolve to the current ``module'' (dynamic shared library\n\
3120 or executable image).\n\
3122 The default version of this hook implements the name resolution rules\n\
3123 for ELF, which has a looser model of global name binding than other\n\
3124 currently supported object file formats.",
3125 bool, (const_tree exp),
3126 default_binds_local_p)
3128 /* Check if profiling code is before or after prologue. */
3129 DEFHOOK
3130 (profile_before_prologue,
3131 "It returns true if target wants profile code emitted before prologue.\n\n\
3132 The default version of this hook use the target macro\n\
3133 @code{PROFILE_BEFORE_PROLOGUE}.",
3134 bool, (void),
3135 default_profile_before_prologue)
3137 /* Return true if a leaf function should stay leaf even with profiling
3138 enabled. */
3139 DEFHOOK
3140 (keep_leaf_when_profiled,
3141 "This target hook returns true if the target wants the leaf flag for\n\
3142 the current function to stay true even if it calls mcount. This might\n\
3143 make sense for targets using the leaf flag only to determine whether a\n\
3144 stack frame needs to be generated or not and for which the call to\n\
3145 mcount is generated before the function prologue.",
3146 bool, (void),
3147 default_keep_leaf_when_profiled)
3149 /* Modify and return the identifier of a DECL's external name,
3150 originally identified by ID, as required by the target,
3151 (eg, append @nn to windows32 stdcall function names).
3152 The default is to return ID without modification. */
3153 DEFHOOK
3154 (mangle_decl_assembler_name,
3155 "Define this hook if you need to postprocess the assembler name generated\n\
3156 by target-independent code. The @var{id} provided to this hook will be\n\
3157 the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,\n\
3158 or the mangled name of the @var{decl} in C++). The return value of the\n\
3159 hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on\n\
3160 your target system. The default implementation of this hook just\n\
3161 returns the @var{id} provided.",
3162 tree, (tree decl, tree id),
3163 default_mangle_decl_assembler_name)
3165 /* Do something target-specific to record properties of the DECL into
3166 the associated SYMBOL_REF. */
3167 DEFHOOK
3168 (encode_section_info,
3169 "Define this hook if references to a symbol or a constant must be\n\
3170 treated differently depending on something about the variable or\n\
3171 function named by the symbol (such as what section it is in).\n\
3173 The hook is executed immediately after rtl has been created for\n\
3174 @var{decl}, which may be a variable or function declaration or\n\
3175 an entry in the constant pool. In either case, @var{rtl} is the\n\
3176 rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}\n\
3177 in this hook; that field may not have been initialized yet.\n\
3179 In the case of a constant, it is safe to assume that the rtl is\n\
3180 a @code{mem} whose address is a @code{symbol_ref}. Most decls\n\
3181 will also have this form, but that is not guaranteed. Global\n\
3182 register variables, for instance, will have a @code{reg} for their\n\
3183 rtl. (Normally the right thing to do with such unusual rtl is\n\
3184 leave it alone.)\n\
3186 The @var{new_decl_p} argument will be true if this is the first time\n\
3187 that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will\n\
3188 be false for subsequent invocations, which will happen for duplicate\n\
3189 declarations. Whether or not anything must be done for the duplicate\n\
3190 declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.\n\
3191 @var{new_decl_p} is always true when the hook is called for a constant.\n\
3193 @cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}\n\
3194 The usual thing for this hook to do is to record flags in the\n\
3195 @code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.\n\
3196 Historically, the name string was modified if it was necessary to\n\
3197 encode more than one bit of information, but this practice is now\n\
3198 discouraged; use @code{SYMBOL_REF_FLAGS}.\n\
3200 The default definition of this hook, @code{default_encode_section_info}\n\
3201 in @file{varasm.cc}, sets a number of commonly-useful bits in\n\
3202 @code{SYMBOL_REF_FLAGS}. Check whether the default does what you need\n\
3203 before overriding it.",
3204 void, (tree decl, rtx rtl, int new_decl_p),
3205 default_encode_section_info)
3207 /* Undo the effects of encode_section_info on the symbol string. */
3208 DEFHOOK
3209 (strip_name_encoding,
3210 "Decode @var{name} and return the real name part, sans\n\
3211 the characters that @code{TARGET_ENCODE_SECTION_INFO}\n\
3212 may have added.",
3213 const char *, (const char *name),
3214 default_strip_name_encoding)
3216 /* If shift optabs for MODE are known to always truncate the shift count,
3217 return the mask that they apply. Return 0 otherwise. */
3218 DEFHOOK
3219 (shift_truncation_mask,
3220 "This function describes how the standard shift patterns for @var{mode}\n\
3221 deal with shifts by negative amounts or by more than the width of the mode.\n\
3222 @xref{shift patterns}.\n\
3224 On many machines, the shift patterns will apply a mask @var{m} to the\n\
3225 shift count, meaning that a fixed-width shift of @var{x} by @var{y} is\n\
3226 equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If\n\
3227 this is true for mode @var{mode}, the function should return @var{m},\n\
3228 otherwise it should return 0. A return value of 0 indicates that no\n\
3229 particular behavior is guaranteed.\n\
3231 Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does\n\
3232 @emph{not} apply to general shift rtxes; it applies only to instructions\n\
3233 that are generated by the named shift patterns.\n\
3235 The default implementation of this function returns\n\
3236 @code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}\n\
3237 and 0 otherwise. This definition is always safe, but if\n\
3238 @code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns\n\
3239 nevertheless truncate the shift count, you may get better code\n\
3240 by overriding it.",
3241 unsigned HOST_WIDE_INT, (machine_mode mode),
3242 default_shift_truncation_mask)
3244 /* Return the number of divisions in the given MODE that should be present,
3245 so that it is profitable to turn the division into a multiplication by
3246 the reciprocal. */
3247 DEFHOOK
3248 (min_divisions_for_recip_mul,
3249 "When @option{-ffast-math} is in effect, GCC tries to optimize\n\
3250 divisions by the same divisor, by turning them into multiplications by\n\
3251 the reciprocal. This target hook specifies the minimum number of divisions\n\
3252 that should be there for GCC to perform the optimization for a variable\n\
3253 of mode @var{mode}. The default implementation returns 3 if the machine\n\
3254 has an instruction for the division, and 2 if it does not.",
3255 unsigned int, (machine_mode mode),
3256 default_min_divisions_for_recip_mul)
3258 DEFHOOK
3259 (truly_noop_truncation,
3260 "This hook returns true if it is safe to ``convert'' a value of\n\
3261 @var{inprec} bits to one of @var{outprec} bits (where @var{outprec} is\n\
3262 smaller than @var{inprec}) by merely operating on it as if it had only\n\
3263 @var{outprec} bits. The default returns true unconditionally, which\n\
3264 is correct for most machines. When @code{TARGET_TRULY_NOOP_TRUNCATION}\n\
3265 returns false, the machine description should provide a @code{trunc}\n\
3266 optab to specify the RTL that performs the required truncation.\n\
3268 If @code{TARGET_MODES_TIEABLE_P} returns false for a pair of modes,\n\
3269 suboptimal code can result if this hook returns true for the corresponding\n\
3270 mode sizes. Making this hook return false in such cases may improve things.",
3271 bool, (poly_uint64 outprec, poly_uint64 inprec),
3272 hook_bool_puint64_puint64_true)
3274 /* If the representation of integral MODE is such that values are
3275 always sign-extended to a wider mode MODE_REP then return
3276 SIGN_EXTEND. Return UNKNOWN otherwise. */
3277 /* Note that the return type ought to be RTX_CODE, but that's not
3278 necessarily defined at this point. */
3279 DEFHOOK
3280 (mode_rep_extended,
3281 "The representation of an integral mode can be such that the values\n\
3282 are always extended to a wider integral mode. Return\n\
3283 @code{SIGN_EXTEND} if values of @var{mode} are represented in\n\
3284 sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}\n\
3285 otherwise. (Currently, none of the targets use zero-extended\n\
3286 representation this way so unlike @code{LOAD_EXTEND_OP},\n\
3287 @code{TARGET_MODE_REP_EXTENDED} is expected to return either\n\
3288 @code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends\n\
3289 @var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next\n\
3290 widest integral mode and currently we take advantage of this fact.)\n\
3292 Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}\n\
3293 value even if the extension is not performed on certain hard registers\n\
3294 as long as for the @code{REGNO_REG_CLASS} of these hard registers\n\
3295 @code{TARGET_CAN_CHANGE_MODE_CLASS} returns false.\n\
3297 Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}\n\
3298 describe two related properties. If you define\n\
3299 @code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want\n\
3300 to define @code{LOAD_EXTEND_OP (mode)} to return the same type of\n\
3301 extension.\n\
3303 In order to enforce the representation of @code{mode},\n\
3304 @code{TARGET_TRULY_NOOP_TRUNCATION} should return false when truncating to\n\
3305 @code{mode}.",
3306 int, (scalar_int_mode mode, scalar_int_mode rep_mode),
3307 default_mode_rep_extended)
3309 DEFHOOK
3310 (setjmp_preserves_nonvolatile_regs_p,
3311 "On some targets, it is assumed that the compiler will spill all pseudos\n\
3312 that are live across a call to @code{setjmp}, while other targets treat\n\
3313 @code{setjmp} calls as normal function calls.\n\
3315 This hook returns false if @code{setjmp} calls do not preserve all\n\
3316 non-volatile registers so that gcc that must spill all pseudos that are\n\
3317 live across @code{setjmp} calls. Define this to return true if the\n\
3318 target does not need to spill all pseudos live across @code{setjmp} calls.\n\
3319 The default implementation conservatively assumes all pseudos must be\n\
3320 spilled across @code{setjmp} calls.",
3321 bool, (void),
3322 hook_bool_void_false)
3324 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
3325 DEFHOOK
3326 (valid_pointer_mode,
3327 "Define this to return nonzero if the port can handle pointers\n\
3328 with machine mode @var{mode}. The default version of this\n\
3329 hook returns true for both @code{ptr_mode} and @code{Pmode}.",
3330 bool, (scalar_int_mode mode),
3331 default_valid_pointer_mode)
3333 /* Disambiguate with errno. */
3334 DEFHOOK
3335 (ref_may_alias_errno,
3336 "Define this to return nonzero if the memory reference @var{ref}\n\
3337 may alias with the system C library errno location. The default\n\
3338 version of this hook assumes the system C library errno location\n\
3339 is either a declaration of type int or accessed by dereferencing\n\
3340 a pointer to int.",
3341 bool, (ao_ref *ref),
3342 default_ref_may_alias_errno)
3344 /* Support for named address spaces. */
3345 #undef HOOK_PREFIX
3346 #define HOOK_PREFIX "TARGET_ADDR_SPACE_"
3347 HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)
3349 /* MODE to use for a pointer into another address space. */
3350 DEFHOOK
3351 (pointer_mode,
3352 "Define this to return the machine mode to use for pointers to\n\
3353 @var{address_space} if the target supports named address spaces.\n\
3354 The default version of this hook returns @code{ptr_mode}.",
3355 scalar_int_mode, (addr_space_t address_space),
3356 default_addr_space_pointer_mode)
3358 /* MODE to use for an address in another address space. */
3359 DEFHOOK
3360 (address_mode,
3361 "Define this to return the machine mode to use for addresses in\n\
3362 @var{address_space} if the target supports named address spaces.\n\
3363 The default version of this hook returns @code{Pmode}.",
3364 scalar_int_mode, (addr_space_t address_space),
3365 default_addr_space_address_mode)
3367 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
3368 in another address space. */
3369 DEFHOOK
3370 (valid_pointer_mode,
3371 "Define this to return nonzero if the port can handle pointers\n\
3372 with machine mode @var{mode} to address space @var{as}. This target\n\
3373 hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,\n\
3374 except that it includes explicit named address space support. The default\n\
3375 version of this hook returns true for the modes returned by either the\n\
3376 @code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}\n\
3377 target hooks for the given address space.",
3378 bool, (scalar_int_mode mode, addr_space_t as),
3379 default_addr_space_valid_pointer_mode)
3381 /* True if an address is a valid memory address to a given named address
3382 space for a given mode. */
3383 DEFHOOK
3384 (legitimate_address_p,
3385 "Define this to return true if @var{exp} is a valid address for mode\n\
3386 @var{mode} in the named address space @var{as} with the use context\n\
3387 @var{ch}. The @var{strict} parameter says whether strict addressing\n\
3388 is in effect after reload has finished. The @var{ch} indicates what\n\
3389 context @var{exp} will be used for. This target hook is the same as the\n\
3390 @code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes\n\
3391 explicit named address space support.",
3392 bool, (machine_mode mode, rtx exp, bool strict, addr_space_t as, code_helper ch),
3393 default_addr_space_legitimate_address_p)
3395 /* Return an updated address to convert an invalid pointer to a named
3396 address space to a valid one. If NULL_RTX is returned use machine
3397 independent methods to make the address valid. */
3398 DEFHOOK
3399 (legitimize_address,
3400 "Define this to modify an invalid address @var{x} to be a valid address\n\
3401 with mode @var{mode} in the named address space @var{as}. This target\n\
3402 hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,\n\
3403 except that it includes explicit named address space support.",
3404 rtx, (rtx x, rtx oldx, machine_mode mode, addr_space_t as),
3405 default_addr_space_legitimize_address)
3407 /* True if one named address space is a subset of another named address. */
3408 DEFHOOK
3409 (subset_p,
3410 "Define this to return whether the @var{subset} named address space is\n\
3411 contained within the @var{superset} named address space. Pointers to\n\
3412 a named address space that is a subset of another named address space\n\
3413 will be converted automatically without a cast if used together in\n\
3414 arithmetic operations. Pointers to a superset address space can be\n\
3415 converted to pointers to a subset address space via explicit casts.",
3416 bool, (addr_space_t subset, addr_space_t superset),
3417 default_addr_space_subset_p)
3419 /* True if 0 is a valid address in the address space, or false if
3420 0 is a NULL in the address space. */
3421 DEFHOOK
3422 (zero_address_valid,
3423 "Define this to modify the default handling of address 0 for the\n\
3424 address space. Return true if 0 should be considered a valid address.",
3425 bool, (addr_space_t as),
3426 default_addr_space_zero_address_valid)
3428 /* Function to convert an rtl expression from one address space to another. */
3429 DEFHOOK
3430 (convert,
3431 "Define this to convert the pointer expression represented by the RTL\n\
3432 @var{op} with type @var{from_type} that points to a named address\n\
3433 space to a new pointer expression with type @var{to_type} that points\n\
3434 to a different named address space. When this hook it called, it is\n\
3435 guaranteed that one of the two address spaces is a subset of the other,\n\
3436 as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.",
3437 rtx, (rtx op, tree from_type, tree to_type),
3438 default_addr_space_convert)
3440 /* Function to encode an address space into dwarf. */
3441 DEFHOOK
3442 (debug,
3443 "Define this to define how the address space is encoded in dwarf.\n\
3444 The result is the value to be used with @code{DW_AT_address_class}.",
3445 int, (addr_space_t as),
3446 default_addr_space_debug)
3448 /* Function to emit custom diagnostic if an address space is used. */
3449 DEFHOOK
3450 (diagnose_usage,
3451 "Define this hook if the availability of an address space depends on\n\
3452 command line options and some diagnostics should be printed when the\n\
3453 address space is used. This hook is called during parsing and allows\n\
3454 to emit a better diagnostic compared to the case where the address space\n\
3455 was not registered with @code{c_register_addr_space}. @var{as} is\n\
3456 the address space as registered with @code{c_register_addr_space}.\n\
3457 @var{loc} is the location of the address space qualifier token.\n\
3458 The default implementation does nothing.",
3459 void, (addr_space_t as, location_t loc),
3460 default_addr_space_diagnose_usage)
3462 HOOK_VECTOR_END (addr_space)
3464 #undef HOOK_PREFIX
3465 #define HOOK_PREFIX "TARGET_"
3467 DEFHOOK
3468 (lower_local_decl_alignment,
3469 "Define this hook to lower alignment of local, parm or result\n\
3470 decl @samp{(@var{decl})}.",
3471 void, (tree decl),
3472 hook_void_tree)
3474 DEFHOOK
3475 (static_rtx_alignment,
3476 "This hook returns the preferred alignment in bits for a\n\
3477 statically-allocated rtx, such as a constant pool entry. @var{mode}\n\
3478 is the mode of the rtx. The default implementation returns\n\
3479 @samp{GET_MODE_ALIGNMENT (@var{mode})}.",
3480 HOST_WIDE_INT, (machine_mode mode),
3481 default_static_rtx_alignment)
3483 DEFHOOK
3484 (constant_alignment,
3485 "This hook returns the alignment in bits of a constant that is being\n\
3486 placed in memory. @var{constant} is the constant and @var{basic_align}\n\
3487 is the alignment that the object would ordinarily have.\n\
3489 The default definition just returns @var{basic_align}.\n\
3491 The typical use of this hook is to increase alignment for string\n\
3492 constants to be word aligned so that @code{strcpy} calls that copy\n\
3493 constants can be done inline. The function\n\
3494 @code{constant_alignment_word_strings} provides such a definition.",
3495 HOST_WIDE_INT, (const_tree constant, HOST_WIDE_INT basic_align),
3496 default_constant_alignment)
3498 DEFHOOK
3499 (translate_mode_attribute,
3500 "Define this hook if during mode attribute processing, the port should\n\
3501 translate machine_mode @var{mode} to another mode. For example, rs6000's\n\
3502 @code{KFmode}, when it is the same as @code{TFmode}.\n\
3504 The default version of the hook returns that mode that was passed in.",
3505 machine_mode, (machine_mode mode),
3506 default_translate_mode_attribute)
3508 /* True if MODE is valid for the target. By "valid", we mean able to
3509 be manipulated in non-trivial ways. In particular, this means all
3510 the arithmetic is supported. */
3511 DEFHOOK
3512 (scalar_mode_supported_p,
3513 "Define this to return nonzero if the port is prepared to handle\n\
3514 insns involving scalar mode @var{mode}. For a scalar mode to be\n\
3515 considered supported, all the basic arithmetic and comparisons\n\
3516 must work.\n\
3518 The default version of this hook returns true for any mode\n\
3519 required to handle the basic C types (as defined by the port).\n\
3520 Included here are the double-word arithmetic supported by the\n\
3521 code in @file{optabs.cc}.",
3522 bool, (scalar_mode mode),
3523 default_scalar_mode_supported_p)
3525 /* Similarly for vector modes. "Supported" here is less strict. At
3526 least some operations are supported; need to check optabs or builtins
3527 for further details. */
3528 DEFHOOK
3529 (vector_mode_supported_p,
3530 "Define this to return nonzero if the current target is prepared to handle\n\
3531 insns involving vector mode @var{mode}. At the very least, it\n\
3532 must have move patterns for this mode.",
3533 bool, (machine_mode mode),
3534 hook_bool_mode_false)
3536 DEFHOOK
3537 (vector_mode_supported_any_target_p,
3538 "Define this to return nonzero if the port is prepared to handle\n\
3539 insns involving vector mode @var{mode} in any target configuration.\n\
3540 Returning @var{true} means that the mode can be used as the @samp{TYPE_MODE}\n\
3541 for vector types.\n\
3543 The default version of this hook returns true. The final mode assigned to\n\
3544 @samp{TYPE_MODE} will also be checked against\n\
3545 @code{TARGET_VECTOR_MODE_SUPPORTED_P} to take target configuration into\n\
3546 account.",
3547 bool, (machine_mode mode),
3548 hook_bool_mode_true)
3550 DEFHOOK
3551 (compatible_vector_types_p,
3552 "Return true if there is no target-specific reason for treating\n\
3553 vector types @var{type1} and @var{type2} as distinct types. The caller\n\
3554 has already checked for target-independent reasons, meaning that the\n\
3555 types are known to have the same mode, to have the same number of elements,\n\
3556 and to have what the caller considers to be compatible element types.\n\
3558 The main reason for defining this hook is to reject pairs of types\n\
3559 that are handled differently by the target's calling convention.\n\
3560 For example, when a new @var{N}-bit vector architecture is added\n\
3561 to a target, the target may want to handle normal @var{N}-bit\n\
3562 @code{VECTOR_TYPE} arguments and return values in the same way as\n\
3563 before, to maintain backwards compatibility. However, it may also\n\
3564 provide new, architecture-specific @code{VECTOR_TYPE}s that are passed\n\
3565 and returned in a more efficient way. It is then important to maintain\n\
3566 a distinction between the ``normal'' @code{VECTOR_TYPE}s and the new\n\
3567 architecture-specific ones.\n\
3569 The default implementation returns true, which is correct for most targets.",
3570 bool, (const_tree type1, const_tree type2),
3571 hook_bool_const_tree_const_tree_true)
3573 DEFHOOK
3574 (vector_alignment,
3575 "This hook can be used to define the alignment for a vector of type\n\
3576 @var{type}, in order to comply with a platform ABI. The default is to\n\
3577 require natural alignment for vector types. The alignment returned by\n\
3578 this hook must be a power-of-two multiple of the default alignment of\n\
3579 the vector element type.",
3580 HOST_WIDE_INT, (const_tree type),
3581 default_vector_alignment)
3583 DEFHOOK
3584 (array_mode,
3585 "Return the mode that GCC should use for an array that has\n\
3586 @var{nelems} elements, with each element having mode @var{mode}.\n\
3587 Return no mode if the target has no special requirements. In the\n\
3588 latter case, GCC looks for an integer mode of the appropriate size\n\
3589 if available and uses BLKmode otherwise. Usually the search for the\n\
3590 integer mode is limited to @code{MAX_FIXED_MODE_SIZE}, but the\n\
3591 @code{TARGET_ARRAY_MODE_SUPPORTED_P} hook allows a larger mode to be\n\
3592 used in specific cases.\n\
3594 The main use of this hook is to specify that an array of vectors should\n\
3595 also have a vector mode. The default implementation returns no mode.",
3596 opt_machine_mode, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3597 hook_optmode_mode_uhwi_none)
3599 /* True if we should try to use a scalar mode to represent an array,
3600 overriding the usual MAX_FIXED_MODE limit. */
3601 DEFHOOK
3602 (array_mode_supported_p,
3603 "Return true if GCC should try to use a scalar mode to store an array\n\
3604 of @var{nelems} elements, given that each element has mode @var{mode}.\n\
3605 Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
3606 and allows GCC to use any defined integer mode.\n\
3608 One use of this hook is to support vector load and store operations\n\
3609 that operate on several homogeneous vectors. For example, ARM NEON\n\
3610 has operations like:\n\
3612 @smallexample\n\
3613 int8x8x3_t vld3_s8 (const int8_t *)\n\
3614 @end smallexample\n\
3616 where the return type is defined as:\n\
3618 @smallexample\n\
3619 typedef struct int8x8x3_t\n\
3620 @{\n\
3621 int8x8_t val[3];\n\
3622 @} int8x8x3_t;\n\
3623 @end smallexample\n\
3625 If this hook allows @code{val} to have a scalar mode, then\n\
3626 @code{int8x8x3_t} can have the same mode. GCC can then store\n\
3627 @code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
3628 bool, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3629 hook_bool_mode_uhwi_false)
3631 DEFHOOK
3632 (libgcc_floating_mode_supported_p,
3633 "Define this to return nonzero if libgcc provides support for the \n\
3634 floating-point mode @var{mode}, which is known to pass \n\
3635 @code{TARGET_SCALAR_MODE_SUPPORTED_P}. The default version of this \n\
3636 hook returns true for all of @code{SFmode}, @code{DFmode}, \n\
3637 @code{XFmode} and @code{TFmode}, if such modes exist.",
3638 bool, (scalar_float_mode mode),
3639 default_libgcc_floating_mode_supported_p)
3641 DEFHOOK
3642 (floatn_mode,
3643 "Define this to return the machine mode to use for the type \n\
3644 @code{_Float@var{n}}, if @var{extended} is false, or the type \n\
3645 @code{_Float@var{n}x}, if @var{extended} is true. If such a type is not\n\
3646 supported, return @code{opt_scalar_float_mode ()}. The default version of\n\
3647 this hook returns @code{SFmode} for @code{_Float32}, @code{DFmode} for\n\
3648 @code{_Float64} and @code{_Float32x} and @code{TFmode} for \n\
3649 @code{_Float128}, if those modes exist and satisfy the requirements for \n\
3650 those types and pass @code{TARGET_SCALAR_MODE_SUPPORTED_P} and \n\
3651 @code{TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P}; for @code{_Float64x}, it \n\
3652 returns the first of @code{XFmode} and @code{TFmode} that exists and \n\
3653 satisfies the same requirements; for other types, it returns \n\
3654 @code{opt_scalar_float_mode ()}. The hook is only called for values\n\
3655 of @var{n} and @var{extended} that are valid according to\n\
3656 ISO/IEC TS 18661-3:2015; that is, @var{n} is one of 32, 64, 128, or,\n\
3657 if @var{extended} is false, 16 or greater than 128 and a multiple of 32.",
3658 opt_scalar_float_mode, (int n, bool extended),
3659 default_floatn_mode)
3661 DEFHOOK
3662 (floatn_builtin_p,
3663 "Define this to return true if the @code{_Float@var{n}} and\n\
3664 @code{_Float@var{n}x} built-in functions should implicitly enable the\n\
3665 built-in function without the @code{__builtin_} prefix in addition to the\n\
3666 normal built-in function with the @code{__builtin_} prefix. The default is\n\
3667 to only enable built-in functions without the @code{__builtin_} prefix for\n\
3668 the GNU C langauge. In strict ANSI/ISO mode, the built-in function without\n\
3669 the @code{__builtin_} prefix is not enabled. The argument @code{FUNC} is the\n\
3670 @code{enum built_in_function} id of the function to be enabled.",
3671 bool, (int func),
3672 default_floatn_builtin_p)
3674 /* Compute cost of moving data from a register of class FROM to one of
3675 TO, using MODE. */
3676 DEFHOOK
3677 (register_move_cost,
3678 "This target hook should return the cost of moving data of mode @var{mode}\n\
3679 from a register in class @var{from} to one in class @var{to}. The classes\n\
3680 are expressed using the enumeration values such as @code{GENERAL_REGS}.\n\
3681 A value of 2 is the default; other values are interpreted relative to\n\
3682 that.\n\
3684 It is not required that the cost always equal 2 when @var{from} is the\n\
3685 same as @var{to}; on some machines it is expensive to move between\n\
3686 registers if they are not general registers.\n\
3688 If reload sees an insn consisting of a single @code{set} between two\n\
3689 hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their\n\
3690 classes returns a value of 2, reload does not check to ensure that the\n\
3691 constraints of the insn are met. Setting a cost of other than 2 will\n\
3692 allow reload to verify that the constraints are met. You should do this\n\
3693 if the @samp{mov@var{m}} pattern's constraints do not allow such copying.\n\
3695 The default version of this function returns 2.",
3696 int, (machine_mode mode, reg_class_t from, reg_class_t to),
3697 default_register_move_cost)
3699 /* Compute cost of moving registers to/from memory. */
3700 /* ??? Documenting the argument types for this hook requires a GFDL
3701 license grant. Also, the documentation uses a different name for RCLASS. */
3702 DEFHOOK
3703 (memory_move_cost,
3704 "This target hook should return the cost of moving data of mode @var{mode}\n\
3705 between a register of class @var{rclass} and memory; @var{in} is @code{false}\n\
3706 if the value is to be written to memory, @code{true} if it is to be read in.\n\
3707 This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.\n\
3708 If moving between registers and memory is more expensive than between two\n\
3709 registers, you should add this target hook to express the relative cost.\n\
3711 If you do not add this target hook, GCC uses a default cost of 4 plus\n\
3712 the cost of copying via a secondary reload register, if one is\n\
3713 needed. If your machine requires a secondary reload register to copy\n\
3714 between memory and a register of @var{rclass} but the reload mechanism is\n\
3715 more complex than copying via an intermediate, use this target hook to\n\
3716 reflect the actual cost of the move.\n\
3718 GCC defines the function @code{memory_move_secondary_cost} if\n\
3719 secondary reloads are needed. It computes the costs due to copying via\n\
3720 a secondary register. If your machine copies from memory using a\n\
3721 secondary register in the conventional way but the default base value of\n\
3722 4 is not correct for your machine, use this target hook to add some other\n\
3723 value to the result of that function. The arguments to that function\n\
3724 are the same as to this target hook.",
3725 int, (machine_mode mode, reg_class_t rclass, bool in),
3726 default_memory_move_cost)
3728 DEFHOOK
3729 (use_by_pieces_infrastructure_p,
3730 "GCC will attempt several strategies when asked to copy between\n\
3731 two areas of memory, or to set, clear or store to memory, for example\n\
3732 when copying a @code{struct}. The @code{by_pieces} infrastructure\n\
3733 implements such memory operations as a sequence of load, store or move\n\
3734 insns. Alternate strategies are to expand the\n\
3735 @code{cpymem} or @code{setmem} optabs, to emit a library call, or to emit\n\
3736 unit-by-unit, loop-based operations.\n\
3738 This target hook should return true if, for a memory operation with a\n\
3739 given @var{size} and @var{alignment}, using the @code{by_pieces}\n\
3740 infrastructure is expected to result in better code generation.\n\
3741 Both @var{size} and @var{alignment} are measured in terms of storage\n\
3742 units.\n\
3744 The parameter @var{op} is one of: @code{CLEAR_BY_PIECES},\n\
3745 @code{MOVE_BY_PIECES}, @code{SET_BY_PIECES}, @code{STORE_BY_PIECES} or\n\
3746 @code{COMPARE_BY_PIECES}. These describe the type of memory operation\n\
3747 under consideration.\n\
3749 The parameter @var{speed_p} is true if the code is currently being\n\
3750 optimized for speed rather than size.\n\
3752 Returning true for higher values of @var{size} can improve code generation\n\
3753 for speed if the target does not provide an implementation of the\n\
3754 @code{cpymem} or @code{setmem} standard names, if the @code{cpymem} or\n\
3755 @code{setmem} implementation would be more expensive than a sequence of\n\
3756 insns, or if the overhead of a library call would dominate that of\n\
3757 the body of the memory operation.\n\
3759 Returning true for higher values of @code{size} may also cause an increase\n\
3760 in code size, for example where the number of insns emitted to perform a\n\
3761 move would be greater than that of a library call.",
3762 bool, (unsigned HOST_WIDE_INT size, unsigned int alignment,
3763 enum by_pieces_operation op, bool speed_p),
3764 default_use_by_pieces_infrastructure_p)
3766 DEFHOOK
3767 (overlap_op_by_pieces_p,
3768 "This target hook should return true if when the @code{by_pieces}\n\
3769 infrastructure is used, an offset adjusted unaligned memory operation\n\
3770 in the smallest integer mode for the last piece operation of a memory\n\
3771 region can be generated to avoid doing more than one smaller operations.",
3772 bool, (void),
3773 hook_bool_void_false)
3775 DEFHOOK
3776 (compare_by_pieces_branch_ratio,
3777 "When expanding a block comparison in MODE, gcc can try to reduce the\n\
3778 number of branches at the expense of more memory operations. This hook\n\
3779 allows the target to override the default choice. It should return the\n\
3780 factor by which branches should be reduced over the plain expansion with\n\
3781 one comparison per @var{mode}-sized piece. A port can also prevent a\n\
3782 particular mode from being used for block comparisons by returning a\n\
3783 negative number from this hook.",
3784 int, (machine_mode mode),
3785 default_compare_by_pieces_branch_ratio)
3787 DEFHOOK
3788 (slow_unaligned_access,
3789 "This hook returns true if memory accesses described by the\n\
3790 @var{mode} and @var{alignment} parameters have a cost many times greater\n\
3791 than aligned accesses, for example if they are emulated in a trap handler.\n\
3792 This hook is invoked only for unaligned accesses, i.e.@: when\n\
3793 @code{@var{alignment} < GET_MODE_ALIGNMENT (@var{mode})}.\n\
3795 When this hook returns true, the compiler will act as if\n\
3796 @code{STRICT_ALIGNMENT} were true when generating code for block\n\
3797 moves. This can cause significantly more instructions to be produced.\n\
3798 Therefore, do not make this hook return true if unaligned accesses only\n\
3799 add a cycle or two to the time for a memory access.\n\
3801 The hook must return true whenever @code{STRICT_ALIGNMENT} is true.\n\
3802 The default implementation returns @code{STRICT_ALIGNMENT}.",
3803 bool, (machine_mode mode, unsigned int align),
3804 default_slow_unaligned_access)
3806 DEFHOOK
3807 (optab_supported_p,
3808 "Return true if the optimizers should use optab @var{op} with\n\
3809 modes @var{mode1} and @var{mode2} for optimization type @var{opt_type}.\n\
3810 The optab is known to have an associated @file{.md} instruction\n\
3811 whose C condition is true. @var{mode2} is only meaningful for conversion\n\
3812 optabs; for direct optabs it is a copy of @var{mode1}.\n\
3814 For example, when called with @var{op} equal to @code{rint_optab} and\n\
3815 @var{mode1} equal to @code{DFmode}, the hook should say whether the\n\
3816 optimizers should use optab @code{rintdf2}.\n\
3818 The default hook returns true for all inputs.",
3819 bool, (int op, machine_mode mode1, machine_mode mode2,
3820 optimization_type opt_type),
3821 default_optab_supported_p)
3823 /* True for MODE if the target expects that registers in this mode will
3824 be allocated to registers in a small register class. The compiler is
3825 allowed to use registers explicitly used in the rtl as spill registers
3826 but it should prevent extending the lifetime of these registers. */
3827 DEFHOOK
3828 (small_register_classes_for_mode_p,
3829 "Define this to return nonzero for machine modes for which the port has\n\
3830 small register classes. If this target hook returns nonzero for a given\n\
3831 @var{mode}, the compiler will try to minimize the lifetime of registers\n\
3832 in @var{mode}. The hook may be called with @code{VOIDmode} as argument.\n\
3833 In this case, the hook is expected to return nonzero if it returns nonzero\n\
3834 for any mode.\n\
3836 On some machines, it is risky to let hard registers live across arbitrary\n\
3837 insns. Typically, these machines have instructions that require values\n\
3838 to be in specific registers (like an accumulator), and reload will fail\n\
3839 if the required hard register is used for another purpose across such an\n\
3840 insn.\n\
3842 Passes before reload do not know which hard registers will be used\n\
3843 in an instruction, but the machine modes of the registers set or used in\n\
3844 the instruction are already known. And for some machines, register\n\
3845 classes are small for, say, integer registers but not for floating point\n\
3846 registers. For example, the AMD x86-64 architecture requires specific\n\
3847 registers for the legacy x86 integer instructions, but there are many\n\
3848 SSE registers for floating point operations. On such targets, a good\n\
3849 strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}\n\
3850 machine modes but zero for the SSE register classes.\n\
3852 The default version of this hook returns false for any mode. It is always\n\
3853 safe to redefine this hook to return with a nonzero value. But if you\n\
3854 unnecessarily define it, you will reduce the amount of optimizations\n\
3855 that can be performed in some cases. If you do not define this hook\n\
3856 to return a nonzero value when it is required, the compiler will run out\n\
3857 of spill registers and print a fatal error message.",
3858 bool, (machine_mode mode),
3859 hook_bool_mode_false)
3861 /* Register number for a flags register. Only needs to be defined if the
3862 target is constrainted to use post-reload comparison elimination. */
3863 DEFHOOKPOD
3864 (flags_regnum,
3865 "If the target has a dedicated flags register, and it needs to use the\n\
3866 post-reload comparison elimination pass, or the delay slot filler pass,\n\
3867 then this value should be set appropriately.",
3868 unsigned int, INVALID_REGNUM)
3870 /* Compute a (partial) cost for rtx X. Return true if the complete
3871 cost has been computed, and false if subexpressions should be
3872 scanned. In either case, *TOTAL contains the cost result. */
3873 /* Note that OUTER_CODE ought to be RTX_CODE, but that's
3874 not necessarily defined at this point. */
3875 DEFHOOK
3876 (rtx_costs,
3877 "This target hook describes the relative costs of RTL expressions.\n\
3879 The cost may depend on the precise form of the expression, which is\n\
3880 available for examination in @var{x}, and the fact that @var{x} appears\n\
3881 as operand @var{opno} of an expression with rtx code @var{outer_code}.\n\
3882 That is, the hook can assume that there is some rtx @var{y} such\n\
3883 that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that\n\
3884 either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or\n\
3885 (b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.\n\
3887 @var{mode} is @var{x}'s machine mode, or for cases like @code{const_int} that\n\
3888 do not have a mode, the mode in which @var{x} is used.\n\
3890 In implementing this hook, you can use the construct\n\
3891 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3892 instructions.\n\
3894 On entry to the hook, @code{*@var{total}} contains a default estimate\n\
3895 for the cost of the expression. The hook should modify this value as\n\
3896 necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}\n\
3897 for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus\n\
3898 operations, and @code{COSTS_N_INSNS (1)} for all other operations.\n\
3900 When optimizing for code size, i.e.@: when @code{speed} is\n\
3901 false, this target hook should be used to estimate the relative\n\
3902 size cost of an expression, again relative to @code{COSTS_N_INSNS}.\n\
3904 The hook returns true when all subexpressions of @var{x} have been\n\
3905 processed, and false when @code{rtx_cost} should recurse.",
3906 bool, (rtx x, machine_mode mode, int outer_code, int opno, int *total, bool speed),
3907 hook_bool_rtx_mode_int_int_intp_bool_false)
3909 /* Compute the cost of X, used as an address. Never called with
3910 invalid addresses. */
3911 DEFHOOK
3912 (address_cost,
3913 "This hook computes the cost of an addressing mode that contains\n\
3914 @var{address}. If not defined, the cost is computed from\n\
3915 the @var{address} expression and the @code{TARGET_RTX_COST} hook.\n\
3917 For most CISC machines, the default cost is a good approximation of the\n\
3918 true cost of the addressing mode. However, on RISC machines, all\n\
3919 instructions normally have the same length and execution time. Hence\n\
3920 all addresses will have equal costs.\n\
3922 In cases where more than one form of an address is known, the form with\n\
3923 the lowest cost will be used. If multiple forms have the same, lowest,\n\
3924 cost, the one that is the most complex will be used.\n\
3926 For example, suppose an address that is equal to the sum of a register\n\
3927 and a constant is used twice in the same basic block. When this macro\n\
3928 is not defined, the address will be computed in a register and memory\n\
3929 references will be indirect through that register. On machines where\n\
3930 the cost of the addressing mode containing the sum is no higher than\n\
3931 that of a simple indirect reference, this will produce an additional\n\
3932 instruction and possibly require an additional register. Proper\n\
3933 specification of this macro eliminates this overhead for such machines.\n\
3935 This hook is never called with an invalid address.\n\
3937 On machines where an address involving more than one register is as\n\
3938 cheap as an address computation involving only one register, defining\n\
3939 @code{TARGET_ADDRESS_COST} to reflect this can cause two registers to\n\
3940 be live over a region of code where only one would have been if\n\
3941 @code{TARGET_ADDRESS_COST} were not defined in that manner. This effect\n\
3942 should be considered in the definition of this macro. Equivalent costs\n\
3943 should probably only be given to addresses with different numbers of\n\
3944 registers on machines with lots of registers.",
3945 int, (rtx address, machine_mode mode, addr_space_t as, bool speed),
3946 default_address_cost)
3948 /* Compute a cost for INSN. */
3949 DEFHOOK
3950 (insn_cost,
3951 "This target hook describes the relative costs of RTL instructions.\n\
3953 In implementing this hook, you can use the construct\n\
3954 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3955 instructions.\n\
3957 When optimizing for code size, i.e.@: when @code{speed} is\n\
3958 false, this target hook should be used to estimate the relative\n\
3959 size cost of an expression, again relative to @code{COSTS_N_INSNS}.",
3960 int, (rtx_insn *insn, bool speed), NULL)
3962 /* Give a cost, in RTX Costs units, for an edge. Like BRANCH_COST, but with
3963 well defined units. */
3964 DEFHOOK
3965 (max_noce_ifcvt_seq_cost,
3966 "This hook returns a value in the same units as @code{TARGET_RTX_COSTS},\n\
3967 giving the maximum acceptable cost for a sequence generated by the RTL\n\
3968 if-conversion pass when conditional execution is not available.\n\
3969 The RTL if-conversion pass attempts to convert conditional operations\n\
3970 that would require a branch to a series of unconditional operations and\n\
3971 @code{mov@var{mode}cc} insns. This hook returns the maximum cost of the\n\
3972 unconditional instructions and the @code{mov@var{mode}cc} insns.\n\
3973 RTL if-conversion is cancelled if the cost of the converted sequence\n\
3974 is greater than the value returned by this hook.\n\
3976 @code{e} is the edge between the basic block containing the conditional\n\
3977 branch to the basic block which would be executed if the condition\n\
3978 were true.\n\
3980 The default implementation of this hook uses the\n\
3981 @code{max-rtl-if-conversion-[un]predictable} parameters if they are set,\n\
3982 and uses a multiple of @code{BRANCH_COST} otherwise.",
3983 unsigned int, (edge e),
3984 default_max_noce_ifcvt_seq_cost)
3986 /* Return true if the given instruction sequence is a good candidate
3987 as a replacement for the if-convertible sequence. */
3988 DEFHOOK
3989 (noce_conversion_profitable_p,
3990 "This hook returns true if the instruction sequence @code{seq} is a good\n\
3991 candidate as a replacement for the if-convertible sequence described in\n\
3992 @code{if_info}.",
3993 bool, (rtx_insn *seq, struct noce_if_info *if_info),
3994 default_noce_conversion_profitable_p)
3996 /* Return true if new_addr should be preferred over the existing address used by
3997 memref in insn. */
3998 DEFHOOK
3999 (new_address_profitable_p,
4000 "Return @code{true} if it is profitable to replace the address in\n\
4001 @var{memref} with @var{new_addr}. This allows targets to prevent the\n\
4002 scheduler from undoing address optimizations. The instruction containing the\n\
4003 memref is @var{insn}. The default implementation returns @code{true}.",
4004 bool, (rtx memref, rtx_insn * insn, rtx new_addr),
4005 default_new_address_profitable_p)
4007 DEFHOOK
4008 (estimated_poly_value,
4009 "Return an estimate of the runtime value of @var{val}, for use in\n\
4010 things like cost calculations or profiling frequencies. @var{kind} is used\n\
4011 to ask for the minimum, maximum, and likely estimates of the value through\n\
4012 the @code{POLY_VALUE_MIN}, @code{POLY_VALUE_MAX} and\n\
4013 @code{POLY_VALUE_LIKELY} values. The default\n\
4014 implementation returns the lowest possible value of @var{val}.",
4015 HOST_WIDE_INT, (poly_int64 val, poly_value_estimate_kind kind),
4016 default_estimated_poly_value)
4018 /* Permit speculative instructions in delay slots during delayed-branch
4019 scheduling. */
4020 DEFHOOK
4021 (no_speculation_in_delay_slots_p,
4022 "This predicate controls the use of the eager delay slot filler to disallow\n\
4023 speculatively executed instructions being placed in delay slots. Targets\n\
4024 such as certain MIPS architectures possess both branches with and without\n\
4025 delay slots. As the eager delay slot filler can decrease performance,\n\
4026 disabling it is beneficial when ordinary branches are available. Use of\n\
4027 delay slot branches filled using the basic filler is often still desirable\n\
4028 as the delay slot can hide a pipeline bubble.",
4029 bool, (void),
4030 hook_bool_void_false)
4032 /* Return where to allocate pseudo for a given hard register initial value. */
4033 DEFHOOK
4034 (allocate_initial_value,
4035 "\n\
4036 When the initial value of a hard register has been copied in a pseudo\n\
4037 register, it is often not necessary to actually allocate another register\n\
4038 to this pseudo register, because the original hard register or a stack slot\n\
4039 it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}\n\
4040 is called at the start of register allocation once for each hard register\n\
4041 that had its initial value copied by using\n\
4042 @code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.\n\
4043 Possible values are @code{NULL_RTX}, if you don't want\n\
4044 to do any special allocation, a @code{REG} rtx---that would typically be\n\
4045 the hard register itself, if it is known not to be clobbered---or a\n\
4046 @code{MEM}.\n\
4047 If you are returning a @code{MEM}, this is only a hint for the allocator;\n\
4048 it might decide to use another register anyways.\n\
4049 You may use @code{current_function_is_leaf} or \n\
4050 @code{REG_N_SETS} in the hook to determine if the hard\n\
4051 register in question will not be clobbered.\n\
4052 The default value of this hook is @code{NULL}, which disables any special\n\
4053 allocation.",
4054 rtx, (rtx hard_reg), NULL)
4056 /* Return nonzero if evaluating UNSPEC X might cause a trap.
4057 FLAGS has the same meaning as in rtlanal.cc: may_trap_p_1. */
4058 DEFHOOK
4059 (unspec_may_trap_p,
4060 "This target hook returns nonzero if @var{x}, an @code{unspec} or\n\
4061 @code{unspec_volatile} operation, might cause a trap. Targets can use\n\
4062 this hook to enhance precision of analysis for @code{unspec} and\n\
4063 @code{unspec_volatile} operations. You may call @code{may_trap_p_1}\n\
4064 to analyze inner elements of @var{x} in which case @var{flags} should be\n\
4065 passed along.",
4066 int, (const_rtx x, unsigned flags),
4067 default_unspec_may_trap_p)
4069 /* Given a register, this hook should return a parallel of registers
4070 to represent where to find the register pieces. Define this hook
4071 if the register and its mode are represented in Dwarf in
4072 non-contiguous locations, or if the register should be
4073 represented in more than one register in Dwarf. Otherwise, this
4074 hook should return NULL_RTX. */
4075 DEFHOOK
4076 (dwarf_register_span,
4077 "Given a register, this hook should return a parallel of registers to\n\
4078 represent where to find the register pieces. Define this hook if the\n\
4079 register and its mode are represented in Dwarf in non-contiguous\n\
4080 locations, or if the register should be represented in more than one\n\
4081 register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.\n\
4082 If not defined, the default is to return @code{NULL_RTX}.",
4083 rtx, (rtx reg),
4084 hook_rtx_rtx_null)
4086 /* Given a register return the mode of the corresponding DWARF frame
4087 register. */
4088 DEFHOOK
4089 (dwarf_frame_reg_mode,
4090 "Given a register, this hook should return the mode which the\n\
4091 corresponding Dwarf frame register should have. This is normally\n\
4092 used to return a smaller mode than the raw mode to prevent call\n\
4093 clobbered parts of a register altering the frame register size",
4094 machine_mode, (int regno),
4095 default_dwarf_frame_reg_mode)
4097 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
4098 entries not corresponding directly to registers below
4099 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
4100 code, given the address of the table. */
4101 DEFHOOK
4102 (init_dwarf_reg_sizes_extra,
4103 "If some registers are represented in Dwarf-2 unwind information in\n\
4104 multiple pieces, define this hook to fill in information about the\n\
4105 sizes of those pieces in the table used by the unwinder at runtime.\n\
4106 It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after\n\
4107 filling in a single size corresponding to each hard register;\n\
4108 @var{address} is the address of the table.",
4109 void, (tree address),
4110 hook_void_tree)
4112 /* Fetch the fixed register(s) which hold condition codes, for
4113 targets where it makes sense to look for duplicate assignments to
4114 the condition codes. This should return true if there is such a
4115 register, false otherwise. The arguments should be set to the
4116 fixed register numbers. Up to two condition code registers are
4117 supported. If there is only one for this target, the int pointed
4118 at by the second argument should be set to -1. */
4119 DEFHOOK
4120 (fixed_condition_code_regs,
4121 "On targets which use a hard\n\
4122 register rather than a pseudo-register to hold condition codes, the\n\
4123 regular CSE passes are often not able to identify cases in which the\n\
4124 hard register is set to a common value. Use this hook to enable a\n\
4125 small pass which optimizes such cases. This hook should return true\n\
4126 to enable this pass, and it should set the integers to which its\n\
4127 arguments point to the hard register numbers used for condition codes.\n\
4128 When there is only one such register, as is true on most systems, the\n\
4129 integer pointed to by @var{p2} should be set to\n\
4130 @code{INVALID_REGNUM}.\n\
4132 The default version of this hook returns false.",
4133 bool, (unsigned int *p1, unsigned int *p2),
4134 hook_bool_uintp_uintp_false)
4136 /* If two condition code modes are compatible, return a condition
4137 code mode which is compatible with both, such that a comparison
4138 done in the returned mode will work for both of the original
4139 modes. If the condition code modes are not compatible, return
4140 VOIDmode. */
4141 DEFHOOK
4142 (cc_modes_compatible,
4143 "On targets which use multiple condition code modes in class\n\
4144 @code{MODE_CC}, it is sometimes the case that a comparison can be\n\
4145 validly done in more than one mode. On such a system, define this\n\
4146 target hook to take two mode arguments and to return a mode in which\n\
4147 both comparisons may be validly done. If there is no such mode,\n\
4148 return @code{VOIDmode}.\n\
4150 The default version of this hook checks whether the modes are the\n\
4151 same. If they are, it returns that mode. If they are different, it\n\
4152 returns @code{VOIDmode}.",
4153 machine_mode, (machine_mode m1, machine_mode m2),
4154 default_cc_modes_compatible)
4156 DEFHOOK
4157 (use_late_prologue_epilogue,
4158 "Return true if the current function's prologue and epilogue should\n\
4159 be emitted late in the pass pipeline, instead of at the usual point.\n\
4161 Normally, the prologue and epilogue sequences are introduced soon after\n\
4162 register allocation is complete. The advantage of this approach is that\n\
4163 it allows the prologue and epilogue instructions to be optimized and\n\
4164 scheduled with other code in the function. However, some targets\n\
4165 require the prologue and epilogue to be the first and last sequences\n\
4166 executed by the function, with no variation allowed. This hook should\n\
4167 return true on such targets.\n\
4169 The default implementation returns false, which is correct for most\n\
4170 targets. The hook should only return true if there is a specific\n\
4171 target limitation that cannot be described in RTL. For example,\n\
4172 the hook might return true if the prologue and epilogue need to switch\n\
4173 between instruction sets.",
4174 bool, (),
4175 hook_bool_void_false)
4177 DEFHOOK
4178 (emit_epilogue_for_sibcall,
4179 "If defined, this hook emits an epilogue sequence for sibling (tail)\n\
4180 call instruction @var{call}. Another way of providing epilogues\n\
4181 for sibling calls is to define the @code{sibcall_epilogue} instruction\n\
4182 pattern; the main advantage of this hook over the pattern is that it\n\
4183 has access to the call instruction.",
4184 void, (rtx_call_insn *call), NULL)
4186 /* Do machine-dependent code transformations. Called just before
4187 delayed-branch scheduling. */
4188 DEFHOOK
4189 (machine_dependent_reorg,
4190 "If non-null, this hook performs a target-specific pass over the\n\
4191 instruction stream. The compiler will run it at all optimization levels,\n\
4192 just before the point at which it normally does delayed-branch scheduling.\n\
4194 The exact purpose of the hook varies from target to target. Some use\n\
4195 it to do transformations that are necessary for correctness, such as\n\
4196 laying out in-function constant pools or avoiding hardware hazards.\n\
4197 Others use it as an opportunity to do some machine-dependent optimizations.\n\
4199 You need not implement the hook if it has nothing to do. The default\n\
4200 definition is null.",
4201 void, (void), NULL)
4203 /* Create the __builtin_va_list type. */
4204 DEFHOOK
4205 (build_builtin_va_list,
4206 "This hook returns a type node for @code{va_list} for the target.\n\
4207 The default version of the hook returns @code{void*}.",
4208 tree, (void),
4209 std_build_builtin_va_list)
4211 /* Enumerate the va list variants. */
4212 DEFHOOK
4213 (enum_va_list_p,
4214 "This target hook is used in function @code{c_common_nodes_and_builtins}\n\
4215 to iterate through the target specific builtin types for va_list. The\n\
4216 variable @var{idx} is used as iterator. @var{pname} has to be a pointer\n\
4217 to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed\n\
4218 variable.\n\
4219 The arguments @var{pname} and @var{ptree} are used to store the result of\n\
4220 this macro and are set to the name of the va_list builtin type and its\n\
4221 internal type.\n\
4222 If the return value of this macro is zero, then there is no more element.\n\
4223 Otherwise the @var{IDX} should be increased for the next call of this\n\
4224 macro to iterate through all types.",
4225 int, (int idx, const char **pname, tree *ptree),
4226 NULL)
4228 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
4229 DEFHOOK
4230 (fn_abi_va_list,
4231 "This hook returns the va_list type of the calling convention specified by\n\
4232 @var{fndecl}.\n\
4233 The default version of this hook returns @code{va_list_type_node}.",
4234 tree, (tree fndecl),
4235 std_fn_abi_va_list)
4237 /* Get the __builtin_va_list type dependent on input type. */
4238 DEFHOOK
4239 (canonical_va_list_type,
4240 "This hook returns the va_list type of the calling convention specified by the\n\
4241 type of @var{type}. If @var{type} is not a valid va_list type, it returns\n\
4242 @code{NULL_TREE}.",
4243 tree, (tree type),
4244 std_canonical_va_list_type)
4246 /* ??? Documenting this hook requires a GFDL license grant. */
4247 DEFHOOK_UNDOC
4248 (expand_builtin_va_start,
4249 "Expand the @code{__builtin_va_start} builtin.",
4250 void, (tree valist, rtx nextarg), NULL)
4252 /* Gimplifies a VA_ARG_EXPR. */
4253 DEFHOOK
4254 (gimplify_va_arg_expr,
4255 "This hook performs target-specific gimplification of\n\
4256 @code{VA_ARG_EXPR}. The first two parameters correspond to the\n\
4257 arguments to @code{va_arg}; the latter two are as in\n\
4258 @code{gimplify.cc:gimplify_expr}.",
4259 tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
4260 std_gimplify_va_arg_expr)
4262 /* Validity-checking routines for PCH files, target-specific.
4263 get_pch_validity returns a pointer to the data to be stored,
4264 and stores the size in its argument. pch_valid_p gets the same
4265 information back and returns NULL if the PCH is valid,
4266 or an error message if not. */
4267 DEFHOOK
4268 (get_pch_validity,
4269 "This hook returns a pointer to the data needed by\n\
4270 @code{TARGET_PCH_VALID_P} and sets\n\
4271 @samp{*@var{sz}} to the size of the data in bytes.",
4272 void *, (size_t *sz),
4273 default_get_pch_validity)
4275 DEFHOOK
4276 (pch_valid_p,
4277 "This hook checks whether the options used to create a PCH file are\n\
4278 compatible with the current settings. It returns @code{NULL}\n\
4279 if so and a suitable error message if not. Error messages will\n\
4280 be presented to the user and must be localized using @samp{_(@var{msg})}.\n\
4282 @var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}\n\
4283 when the PCH file was created and @var{sz} is the size of that data in bytes.\n\
4284 It's safe to assume that the data was created by the same version of the\n\
4285 compiler, so no format checking is needed.\n\
4287 The default definition of @code{default_pch_valid_p} should be\n\
4288 suitable for most targets.",
4289 const char *, (const void *data, size_t sz),
4290 default_pch_valid_p)
4292 DEFHOOK
4293 (prepare_pch_save,
4294 "Called before writing out a PCH file. If the target has some\n\
4295 garbage-collected data that needs to be in a particular state on PCH loads,\n\
4296 it can use this hook to enforce that state. Very few targets need\n\
4297 to do anything here.",
4298 void, (void),
4299 hook_void_void)
4301 /* If nonnull, this function checks whether a PCH file with the
4302 given set of target flags can be used. It returns NULL if so,
4303 otherwise it returns an error message. */
4304 DEFHOOK
4305 (check_pch_target_flags,
4306 "If this hook is nonnull, the default implementation of\n\
4307 @code{TARGET_PCH_VALID_P} will use it to check for compatible values\n\
4308 of @code{target_flags}. @var{pch_flags} specifies the value that\n\
4309 @code{target_flags} had when the PCH file was created. The return\n\
4310 value is the same as for @code{TARGET_PCH_VALID_P}.",
4311 const char *, (int pch_flags), NULL)
4313 /* True if the compiler should give an enum type only as many
4314 bytes as it takes to represent the range of possible values of
4315 that type. */
4316 DEFHOOK
4317 (default_short_enums,
4318 "This target hook should return true if the compiler should give an\n\
4319 @code{enum} type only as many bytes as it takes to represent the range\n\
4320 of possible values of that type. It should return false if all\n\
4321 @code{enum} types should be allocated like @code{int}.\n\
4323 The default is to return false.",
4324 bool, (void),
4325 hook_bool_void_false)
4327 /* This target hook returns an rtx that is used to store the address
4328 of the current frame into the built-in setjmp buffer. */
4329 DEFHOOK
4330 (builtin_setjmp_frame_value,
4331 "This target hook should return an rtx that is used to store\n\
4332 the address of the current frame into the built in @code{setjmp} buffer.\n\
4333 The default value, @code{virtual_stack_vars_rtx}, is correct for most\n\
4334 machines. One reason you may need to define this target hook is if\n\
4335 @code{hard_frame_pointer_rtx} is the appropriate value on your machine.",
4336 rtx, (void),
4337 default_builtin_setjmp_frame_value)
4339 /* This target hook should manipulate the outputs, inputs, constraints,
4340 and clobbers the port wishes for pre-processing the asm. */
4341 DEFHOOK
4342 (md_asm_adjust,
4343 "This target hook may add @dfn{clobbers} to @var{clobbers} and\n\
4344 @var{clobbered_regs} for any hard regs the port wishes to automatically\n\
4345 clobber for an asm. It can also add hard registers that are used by the\n\
4346 asm to @var{uses}. The @var{outputs} and @var{inputs} may be inspected\n\
4347 to avoid clobbering a register that is already used by the asm. @var{loc}\n\
4348 is the source location of the asm.\n\
4350 It may modify the @var{outputs}, @var{inputs}, @var{input_modes}, and\n\
4351 @var{constraints} as necessary for other pre-processing. In this case the\n\
4352 return value is a sequence of insns to emit after the asm. Note that\n\
4353 changes to @var{inputs} must be accompanied by the corresponding changes\n\
4354 to @var{input_modes}.",
4355 rtx_insn *,
4356 (vec<rtx>& outputs, vec<rtx>& inputs, vec<machine_mode>& input_modes,
4357 vec<const char *>& constraints, vec<rtx>& usess, vec<rtx>& clobbers,
4358 HARD_REG_SET& clobbered_regs, location_t loc),
4359 NULL)
4361 /* This target hook allows the backend to specify a calling convention
4362 in the debug information. This function actually returns an
4363 enum dwarf_calling_convention, but because of forward declarations
4364 and not wanting to include dwarf2.h everywhere target.h is included
4365 the function is being declared as an int. */
4366 DEFHOOK
4367 (dwarf_calling_convention,
4368 "Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to\n\
4369 be emitted for each function. Instead of an integer return the enum\n\
4370 value for the @code{DW_CC_} tag.",
4371 int, (const_tree function),
4372 hook_int_const_tree_0)
4374 /* This target hook allows the backend to emit frame-related insns that
4375 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
4376 engine will invoke it on insns of the form
4377 (set (reg) (unspec [...] UNSPEC_INDEX))
4379 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
4380 to let the backend emit the call frame instructions. */
4381 DEFHOOK
4382 (dwarf_handle_frame_unspec,
4383 "This target hook allows the backend to emit frame-related insns that\n\
4384 contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging\n\
4385 info engine will invoke it on insns of the form\n\
4386 @smallexample\n\
4387 (set (reg) (unspec [@dots{}] UNSPEC_INDEX))\n\
4388 @end smallexample\n\
4389 and\n\
4390 @smallexample\n\
4391 (set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).\n\
4392 @end smallexample\n\
4393 to let the backend emit the call frame instructions. @var{label} is\n\
4394 the CFI label attached to the insn, @var{pattern} is the pattern of\n\
4395 the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.",
4396 void, (const char *label, rtx pattern, int index), NULL)
4398 DEFHOOK
4399 (dwarf_poly_indeterminate_value,
4400 "Express the value of @code{poly_int} indeterminate @var{i} as a DWARF\n\
4401 expression, with @var{i} counting from 1. Return the number of a DWARF\n\
4402 register @var{R} and set @samp{*@var{factor}} and @samp{*@var{offset}} such\n\
4403 that the value of the indeterminate is:\n\
4404 @smallexample\n\
4405 value_of(@var{R}) / @var{factor} - @var{offset}\n\
4406 @end smallexample\n\
4408 A target only needs to define this hook if it sets\n\
4409 @samp{NUM_POLY_INT_COEFFS} to a value greater than 1.",
4410 unsigned int, (unsigned int i, unsigned int *factor, int *offset),
4411 default_dwarf_poly_indeterminate_value)
4413 /* ??? Documenting this hook requires a GFDL license grant. */
4414 DEFHOOK_UNDOC
4415 (stdarg_optimize_hook,
4416 "Perform architecture specific checking of statements gimplified\
4417 from @code{VA_ARG_EXPR}. @var{stmt} is the statement. Returns true if\
4418 the statement doesn't need to be checked for @code{va_list} references.",
4419 bool, (struct stdarg_info *ai, const gimple *stmt), NULL)
4421 /* This target hook allows the operating system to override the DECL
4422 that represents the external variable that contains the stack
4423 protection guard variable. The type of this DECL is ptr_type_node. */
4424 DEFHOOK
4425 (stack_protect_guard,
4426 "This hook returns a @code{DECL} node for the external variable to use\n\
4427 for the stack protection guard. This variable is initialized by the\n\
4428 runtime to some random value and is used to initialize the guard value\n\
4429 that is placed at the top of the local stack frame. The type of this\n\
4430 variable must be @code{ptr_type_node}.\n\
4432 The default version of this hook creates a variable called\n\
4433 @samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.",
4434 tree, (void),
4435 default_stack_protect_guard)
4437 /* This target hook allows the operating system to override the CALL_EXPR
4438 that is invoked when a check vs the guard variable fails. */
4439 DEFHOOK
4440 (stack_protect_fail,
4441 "This hook returns a @code{CALL_EXPR} that alerts the runtime that the\n\
4442 stack protect guard variable has been modified. This expression should\n\
4443 involve a call to a @code{noreturn} function.\n\
4445 The default version of this hook invokes a function called\n\
4446 @samp{__stack_chk_fail}, taking no arguments. This function is\n\
4447 normally defined in @file{libgcc2.c}.",
4448 tree, (void),
4449 default_external_stack_protect_fail)
4451 /* This target hook allows the operating system to disable the default stack
4452 protector runtime support. */
4453 DEFHOOK
4454 (stack_protect_runtime_enabled_p,
4455 "Returns true if the target wants GCC's default stack protect runtime support,\n\
4456 otherwise return false. The default implementation always returns true.",
4457 bool, (void),
4458 hook_bool_void_true)
4460 DEFHOOK
4461 (have_strub_support_for,
4462 "Returns true if the target supports stack scrubbing for the given function\n\
4463 or type, otherwise return false. The default implementation always returns\n\
4464 true.",
4465 bool, (tree),
4466 hook_bool_tree_true)
4468 DEFHOOK
4469 (have_speculation_safe_value,
4470 "This hook is used to determine the level of target support for\n\
4471 @code{__builtin_speculation_safe_value}. If called with an argument\n\
4472 of false, it returns true if the target has been modified to support\n\
4473 this builtin. If called with an argument of true, it returns true\n\
4474 if the target requires active mitigation execution might be speculative.\n\
4476 The default implementation returns false if the target does not define\n\
4477 a pattern named @code{speculation_barrier}. Else it returns true\n\
4478 for the first case and whether the pattern is enabled for the current\n\
4479 compilation for the second case.\n\
4481 For targets that have no processors that can execute instructions\n\
4482 speculatively an alternative implemenation of this hook is available:\n\
4483 simply redefine this hook to @code{speculation_safe_value_not_needed}\n\
4484 along with your other target hooks.",
4485 bool, (bool active), default_have_speculation_safe_value)
4487 DEFHOOK
4488 (speculation_safe_value,
4489 "This target hook can be used to generate a target-specific code\n\
4490 sequence that implements the @code{__builtin_speculation_safe_value}\n\
4491 built-in function. The function must always return @var{val} in\n\
4492 @var{result} in mode @var{mode} when the cpu is not executing\n\
4493 speculatively, but must never return that when speculating until it\n\
4494 is known that the speculation will not be unwound. The hook supports\n\
4495 two primary mechanisms for implementing the requirements. The first\n\
4496 is to emit a speculation barrier which forces the processor to wait\n\
4497 until all prior speculative operations have been resolved; the second\n\
4498 is to use a target-specific mechanism that can track the speculation\n\
4499 state and to return @var{failval} if it can determine that\n\
4500 speculation must be unwound at a later time.\n\
4502 The default implementation simply copies @var{val} to @var{result} and\n\
4503 emits a @code{speculation_barrier} instruction if that is defined.",
4504 rtx, (machine_mode mode, rtx result, rtx val, rtx failval),
4505 default_speculation_safe_value)
4507 DEFHOOK
4508 (predict_doloop_p,
4509 "Return true if we can predict it is possible to use a low-overhead loop\n\
4510 for a particular loop. The parameter @var{loop} is a pointer to the loop.\n\
4511 This target hook is required only when the target supports low-overhead\n\
4512 loops, and will help ivopts to make some decisions.\n\
4513 The default version of this hook returns false.",
4514 bool, (class loop *loop),
4515 default_predict_doloop_p)
4517 DEFHOOKPOD
4518 (have_count_reg_decr_p,
4519 "Return true if the target supports hardware count register for decrement\n\
4520 and branch.\n\
4521 The default value is false.",
4522 bool, false)
4524 DEFHOOKPOD
4525 (doloop_cost_for_generic,
4526 "One IV candidate dedicated for doloop is introduced in IVOPTs, we can\n\
4527 calculate the computation cost of adopting it to any generic IV use by\n\
4528 function get_computation_cost as before. But for targets which have\n\
4529 hardware count register support for decrement and branch, it may have to\n\
4530 move IV value from hardware count register to general purpose register\n\
4531 while doloop IV candidate is used for generic IV uses. It probably takes\n\
4532 expensive penalty. This hook allows target owners to define the cost for\n\
4533 this especially for generic IV uses.\n\
4534 The default value is zero.",
4535 int64_t, 0)
4537 DEFHOOKPOD
4538 (doloop_cost_for_address,
4539 "One IV candidate dedicated for doloop is introduced in IVOPTs, we can\n\
4540 calculate the computation cost of adopting it to any address IV use by\n\
4541 function get_computation_cost as before. But for targets which have\n\
4542 hardware count register support for decrement and branch, it may have to\n\
4543 move IV value from hardware count register to general purpose register\n\
4544 while doloop IV candidate is used for address IV uses. It probably takes\n\
4545 expensive penalty. This hook allows target owners to define the cost for\n\
4546 this escpecially for address IV uses.\n\
4547 The default value is zero.",
4548 int64_t, 0)
4550 DEFHOOK
4551 (can_use_doloop_p,
4552 "Return true if it is possible to use low-overhead loops (@code{doloop_end}\n\
4553 and @code{doloop_begin}) for a particular loop. @var{iterations} gives the\n\
4554 exact number of iterations, or 0 if not known. @var{iterations_max} gives\n\
4555 the maximum number of iterations, or 0 if not known. @var{loop_depth} is\n\
4556 the nesting depth of the loop, with 1 for innermost loops, 2 for loops that\n\
4557 contain innermost loops, and so on. @var{entered_at_top} is true if the\n\
4558 loop is only entered from the top.\n\
4560 This hook is only used if @code{doloop_end} is available. The default\n\
4561 implementation returns true. You can use @code{can_use_doloop_if_innermost}\n\
4562 if the loop must be the innermost, and if there are no other restrictions.",
4563 bool, (const widest_int &iterations, const widest_int &iterations_max,
4564 unsigned int loop_depth, bool entered_at_top),
4565 hook_bool_wint_wint_uint_bool_true)
4567 /* Returns NULL if target supports the insn within a doloop block,
4568 otherwise it returns an error message. */
4569 DEFHOOK
4570 (invalid_within_doloop,
4571 "\n\
4572 Take an instruction in @var{insn} and return NULL if it is valid within a\n\
4573 low-overhead loop, otherwise return a string explaining why doloop\n\
4574 could not be applied.\n\
4576 Many targets use special registers for low-overhead looping. For any\n\
4577 instruction that clobbers these this function should return a string indicating\n\
4578 the reason why the doloop could not be applied.\n\
4579 By default, the RTL loop optimizer does not use a present doloop pattern for\n\
4580 loops containing function calls or branch on table instructions.",
4581 const char *, (const rtx_insn *insn),
4582 default_invalid_within_doloop)
4584 /* Returns the machine mode which the target prefers for doloop IV. */
4585 DEFHOOK
4586 (preferred_doloop_mode,
4587 "This hook takes a @var{mode} for a doloop IV, where @code{mode} is the\n\
4588 original mode for the operation. If the target prefers an alternate\n\
4589 @code{mode} for the operation, then this hook should return that mode;\n\
4590 otherwise the original @code{mode} should be returned. For example, on a\n\
4591 64-bit target, @code{DImode} might be preferred over @code{SImode}. Both the\n\
4592 original and the returned modes should be @code{MODE_INT}.",
4593 machine_mode,
4594 (machine_mode mode),
4595 default_preferred_doloop_mode)
4597 /* Returns true for a legitimate combined insn. */
4598 DEFHOOK
4599 (legitimate_combined_insn,
4600 "Take an instruction in @var{insn} and return @code{false} if the instruction\n\
4601 is not appropriate as a combination of two or more instructions. The\n\
4602 default is to accept all instructions.",
4603 bool, (rtx_insn *insn),
4604 hook_bool_rtx_insn_true)
4606 DEFHOOK
4607 (valid_dllimport_attribute_p,
4608 "@var{decl} is a variable or function with @code{__attribute__((dllimport))}\n\
4609 specified. Use this hook if the target needs to add extra validation\n\
4610 checks to @code{handle_dll_attribute}.",
4611 bool, (const_tree decl),
4612 hook_bool_const_tree_true)
4614 /* If non-zero, align constant anchors in CSE to a multiple of this
4615 value. */
4616 DEFHOOKPOD
4617 (const_anchor,
4618 "On some architectures it can take multiple instructions to synthesize\n\
4619 a constant. If there is another constant already in a register that\n\
4620 is close enough in value then it is preferable that the new constant\n\
4621 is computed from this register using immediate addition or\n\
4622 subtraction. We accomplish this through CSE. Besides the value of\n\
4623 the constant we also add a lower and an upper constant anchor to the\n\
4624 available expressions. These are then queried when encountering new\n\
4625 constants. The anchors are computed by rounding the constant up and\n\
4626 down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.\n\
4627 @code{TARGET_CONST_ANCHOR} should be the maximum positive value\n\
4628 accepted by immediate-add plus one. We currently assume that the\n\
4629 value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on\n\
4630 MIPS, where add-immediate takes a 16-bit signed value,\n\
4631 @code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value\n\
4632 is zero, which disables this optimization.",
4633 unsigned HOST_WIDE_INT, 0)
4635 /* Defines, which target-dependent bits (upper 16) are used by port */
4636 DEFHOOK
4637 (memmodel_check,
4638 "Validate target specific memory model mask bits. When NULL no target specific\n\
4639 memory model bits are allowed.",
4640 unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)
4642 /* Defines an offset bitwise ored into shifted address to get corresponding
4643 Address Sanitizer shadow address, or -1 if Address Sanitizer is not
4644 supported by the target. */
4645 DEFHOOK
4646 (asan_shadow_offset,
4647 "Return the offset bitwise ored into shifted address to get corresponding\n\
4648 Address Sanitizer shadow memory address. NULL if Address Sanitizer is not\n\
4649 supported by the target. May return 0 if Address Sanitizer is not supported\n\
4650 by a subtarget.",
4651 unsigned HOST_WIDE_INT, (void),
4652 NULL)
4654 /* Functions relating to calls - argument passing, returns, etc. */
4655 /* Members of struct call have no special macro prefix. */
4656 HOOK_VECTOR (TARGET_CALLS, calls)
4658 DEFHOOK
4659 (promote_function_mode,
4660 "Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or\n\
4661 function return values. The target hook should return the new mode\n\
4662 and possibly change @code{*@var{punsignedp}} if the promotion should\n\
4663 change signedness. This function is called only for scalar @emph{or\n\
4664 pointer} types.\n\
4666 @var{for_return} allows to distinguish the promotion of arguments and\n\
4667 return values. If it is @code{1}, a return value is being promoted and\n\
4668 @code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.\n\
4669 If it is @code{2}, the returned mode should be that of the register in\n\
4670 which an incoming parameter is copied, or the outgoing result is computed;\n\
4671 then the hook should return the same mode as @code{promote_mode}, though\n\
4672 the signedness may be different.\n\
4674 @var{type} can be NULL when promoting function arguments of libcalls.\n\
4676 The default is to not promote arguments and return values. You can\n\
4677 also define the hook to @code{default_promote_function_mode_always_promote}\n\
4678 if you would like to apply the same rules given by @code{PROMOTE_MODE}.",
4679 machine_mode, (const_tree type, machine_mode mode, int *punsignedp,
4680 const_tree funtype, int for_return),
4681 default_promote_function_mode)
4683 DEFHOOK
4684 (promote_prototypes,
4685 "This target hook returns @code{true} if an argument declared in a\n\
4686 prototype as an integral type smaller than @code{int} should actually be\n\
4687 passed as an @code{int}. In addition to avoiding errors in certain\n\
4688 cases of mismatch, it also makes for better code on certain machines.\n\
4689 The default is to not promote prototypes.",
4690 bool, (const_tree fntype),
4691 hook_bool_const_tree_false)
4693 DEFHOOK
4694 (struct_value_rtx,
4695 "This target hook should return the location of the structure value\n\
4696 address (normally a @code{mem} or @code{reg}), or 0 if the address is\n\
4697 passed as an ``invisible'' first argument. Note that @var{fndecl} may\n\
4698 be @code{NULL}, for libcalls. You do not need to define this target\n\
4699 hook if the address is always passed as an ``invisible'' first\n\
4700 argument.\n\
4702 On some architectures the place where the structure value address\n\
4703 is found by the called function is not the same place that the\n\
4704 caller put it. This can be due to register windows, or it could\n\
4705 be because the function prologue moves it to a different place.\n\
4706 @var{incoming} is @code{1} or @code{2} when the location is needed in\n\
4707 the context of the called function, and @code{0} in the context of\n\
4708 the caller.\n\
4710 If @var{incoming} is nonzero and the address is to be found on the\n\
4711 stack, return a @code{mem} which refers to the frame pointer. If\n\
4712 @var{incoming} is @code{2}, the result is being used to fetch the\n\
4713 structure value address at the beginning of a function. If you need\n\
4714 to emit adjusting code, you should do it at this point.",
4715 rtx, (tree fndecl, int incoming),
4716 hook_rtx_tree_int_null)
4718 DEFHOOKPOD
4719 (omit_struct_return_reg,
4720 "Normally, when a function returns a structure by memory, the address\n\
4721 is passed as an invisible pointer argument, but the compiler also\n\
4722 arranges to return the address from the function like it would a normal\n\
4723 pointer return value. Define this to true if that behavior is\n\
4724 undesirable on your target.",
4725 bool, false)
4727 DEFHOOK
4728 (return_in_memory,
4729 "This target hook should return a nonzero value to say to return the\n\
4730 function value in memory, just as large structures are always returned.\n\
4731 Here @var{type} will be the data type of the value, and @var{fntype}\n\
4732 will be the type of the function doing the returning, or @code{NULL} for\n\
4733 libcalls.\n\
4735 Note that values of mode @code{BLKmode} must be explicitly handled\n\
4736 by this function. Also, the option @option{-fpcc-struct-return}\n\
4737 takes effect regardless of this macro. On most systems, it is\n\
4738 possible to leave the hook undefined; this causes a default\n\
4739 definition to be used, whose value is the constant 1 for @code{BLKmode}\n\
4740 values, and 0 otherwise.\n\
4742 Do not use this hook to indicate that structures and unions should always\n\
4743 be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}\n\
4744 to indicate this.",
4745 bool, (const_tree type, const_tree fntype),
4746 default_return_in_memory)
4748 DEFHOOK
4749 (return_in_msb,
4750 "This hook should return true if values of type @var{type} are returned\n\
4751 at the most significant end of a register (in other words, if they are\n\
4752 padded at the least significant end). You can assume that @var{type}\n\
4753 is returned in a register; the caller is required to check this.\n\
4755 Note that the register provided by @code{TARGET_FUNCTION_VALUE} must\n\
4756 be able to hold the complete return value. For example, if a 1-, 2-\n\
4757 or 3-byte structure is returned at the most significant end of a\n\
4758 4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an\n\
4759 @code{SImode} rtx.",
4760 bool, (const_tree type),
4761 hook_bool_const_tree_false)
4763 /* Return true if a parameter must be passed by reference. TYPE may
4764 be null if this is a libcall. CA may be null if this query is
4765 from __builtin_va_arg. */
4766 DEFHOOK
4767 (pass_by_reference,
4768 "This target hook should return @code{true} if argument @var{arg} at the\n\
4769 position indicated by @var{cum} should be passed by reference. This\n\
4770 predicate is queried after target independent reasons for being\n\
4771 passed by reference, such as @code{TREE_ADDRESSABLE (@var{arg}.type)}.\n\
4773 If the hook returns true, a copy of that argument is made in memory and a\n\
4774 pointer to the argument is passed instead of the argument itself.\n\
4775 The pointer is passed in whatever way is appropriate for passing a pointer\n\
4776 to that type.",
4777 bool,
4778 (cumulative_args_t cum, const function_arg_info &arg),
4779 hook_bool_CUMULATIVE_ARGS_arg_info_false)
4781 DEFHOOK
4782 (expand_builtin_saveregs,
4783 "If defined, this hook produces the machine-specific code for a call to\n\
4784 @code{__builtin_saveregs}. This code will be moved to the very\n\
4785 beginning of the function, before any parameter access are made. The\n\
4786 return value of this function should be an RTX that contains the value\n\
4787 to use as the return of @code{__builtin_saveregs}.",
4788 rtx, (void),
4789 default_expand_builtin_saveregs)
4791 /* Returns pretend_argument_size. */
4792 DEFHOOK
4793 (setup_incoming_varargs,
4794 "This target hook offers an alternative to using\n\
4795 @code{__builtin_saveregs} and defining the hook\n\
4796 @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous\n\
4797 register arguments into the stack so that all the arguments appear to\n\
4798 have been passed consecutively on the stack. Once this is done, you can\n\
4799 use the standard implementation of varargs that works for machines that\n\
4800 pass all their arguments on the stack.\n\
4802 The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data\n\
4803 structure, containing the values that are obtained after processing the\n\
4804 named arguments. The argument @var{arg} describes the last of these named\n\
4805 arguments. The argument @var{arg} should not be used if the function type\n\
4806 satisfies @code{TYPE_NO_NAMED_ARGS_STDARG_P}, since in that case there are\n\
4807 no named arguments and all arguments are accessed with @code{va_arg}.\n\
4809 The target hook should do two things: first, push onto the stack all the\n\
4810 argument registers @emph{not} used for the named arguments, and second,\n\
4811 store the size of the data thus pushed into the @code{int}-valued\n\
4812 variable pointed to by @var{pretend_args_size}. The value that you\n\
4813 store here will serve as additional offset for setting up the stack\n\
4814 frame.\n\
4816 Because you must generate code to push the anonymous arguments at\n\
4817 compile time without knowing their data types,\n\
4818 @code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that\n\
4819 have just a single category of argument register and use it uniformly\n\
4820 for all data types.\n\
4822 If the argument @var{second_time} is nonzero, it means that the\n\
4823 arguments of the function are being analyzed for the second time. This\n\
4824 happens for an inline function, which is not actually compiled until the\n\
4825 end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should\n\
4826 not generate any instructions in this case.",
4827 void, (cumulative_args_t args_so_far, const function_arg_info &arg,
4828 int *pretend_args_size, int second_time),
4829 default_setup_incoming_varargs)
4831 DEFHOOK
4832 (start_call_args,
4833 "This target hook is invoked while generating RTL for a function call,\n\
4834 after the argument values have been computed, and after stack arguments\n\
4835 have been initialized, but before register arguments have been moved into\n\
4836 their ABI-defined hard register locations. It precedes calls to the related\n\
4837 hooks @code{TARGET_CALL_ARGS} and @code{TARGET_END_CALL_ARGS}.\n\
4838 The significance of this position in the call expansion is that:\n\
4840 @itemize @bullet\n\
4841 @item\n\
4842 No argument registers are live.\n\
4843 @item\n\
4844 Although a call sequence can in general involve subcalls (such as using\n\
4845 @code{memcpy} to copy large arguments), no such subcall will occur between\n\
4846 the call to this hook and the generation of the main call instruction.\n\
4847 @end itemize\n\
4849 The single argument @var{complete_args} is the state of the target\n\
4850 function's cumulative argument information after the final call to\n\
4851 @code{TARGET_FUNCTION_ARG}.\n\
4853 The hook can be used for things like switching processor mode, in cases\n\
4854 where different calls need different processor modes. Most ports do not\n\
4855 need to implement anything for this hook.",
4856 void, (cumulative_args_t complete_args),
4857 hook_void_CUMULATIVE_ARGS)
4859 DEFHOOK
4860 (call_args,
4861 "While generating RTL for a function call, this target hook is invoked once\n\
4862 for each argument passed to the function, either a register returned by\n\
4863 @code{TARGET_FUNCTION_ARG} or a memory location. It is called just\n\
4864 before the point where argument registers are stored.\n\
4866 @var{complete_args} is the state of the target function's cumulative\n\
4867 argument information after the final call to @code{TARGET_FUNCTION_ARG}.\n\
4868 @var{loc} is the location of the argument. @var{type} is the type of\n\
4869 the function being called, or @code{NULL_TREE} for libcalls.\n\
4871 For functions without arguments, the hook is called once with @code{pc_rtx}\n\
4872 passed instead of an argument register.\n\
4874 This functionality can be used to perform special setup of call argument\n\
4875 registers, if a target needs it. Most ports do not need to implement\n\
4876 anything for this hook.",
4877 void, (cumulative_args_t complete_args, rtx loc, tree type),
4878 hook_void_CUMULATIVE_ARGS_rtx_tree)
4880 DEFHOOK
4881 (end_call_args,
4882 "This target hook is invoked while generating RTL for a function call,\n\
4883 just after the point where the return reg is copied into a pseudo. It\n\
4884 signals that all the call argument and return registers for the just\n\
4885 emitted call are now no longer in use. @var{complete_args} is the\n\
4886 state of the target function's cumulative argument information after\n\
4887 the final call to @code{TARGET_FUNCTION_ARG}.\n\
4889 Most ports do not need to implement anything for this hook.",
4890 void, (cumulative_args_t complete_args),
4891 hook_void_CUMULATIVE_ARGS)
4893 DEFHOOK
4894 (push_argument,
4895 "This target hook returns @code{true} if push instructions will be\n\
4896 used to pass outgoing arguments. When the push instruction usage is\n\
4897 optional, @var{npush} is nonzero to indicate the number of bytes to\n\
4898 push. Otherwise, @var{npush} is zero. If the target machine does not\n\
4899 have a push instruction or push instruction should be avoided,\n\
4900 @code{false} should be returned. That directs GCC to use an alternate\n\
4901 strategy: to allocate the entire argument block and then store the\n\
4902 arguments into it. If this target hook may return @code{true},\n\
4903 @code{PUSH_ROUNDING} must be defined.",
4904 bool, (unsigned int npush),
4905 default_push_argument)
4907 DEFHOOK
4908 (strict_argument_naming,
4909 "Define this hook to return @code{true} if the location where a function\n\
4910 argument is passed depends on whether or not it is a named argument.\n\
4912 This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}\n\
4913 is set for varargs and stdarg functions. If this hook returns\n\
4914 @code{true}, the @var{named} argument is always true for named\n\
4915 arguments, and false for unnamed arguments. If it returns @code{false},\n\
4916 but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},\n\
4917 then all arguments are treated as named. Otherwise, all named arguments\n\
4918 except the last are treated as named.\n\
4920 You need not define this hook if it always returns @code{false}.",
4921 bool, (cumulative_args_t ca),
4922 hook_bool_CUMULATIVE_ARGS_false)
4924 /* Returns true if we should use
4925 targetm.calls.setup_incoming_varargs() and/or
4926 targetm.calls.strict_argument_naming(). */
4927 DEFHOOK
4928 (pretend_outgoing_varargs_named,
4929 "If you need to conditionally change ABIs so that one works with\n\
4930 @code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither\n\
4931 @code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was\n\
4932 defined, then define this hook to return @code{true} if\n\
4933 @code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.\n\
4934 Otherwise, you should not define this hook.",
4935 bool, (cumulative_args_t ca),
4936 default_pretend_outgoing_varargs_named)
4938 /* Given a complex type T, return true if a parameter of type T
4939 should be passed as two scalars. */
4940 DEFHOOK
4941 (split_complex_arg,
4942 "This hook should return true if parameter of type @var{type} are passed\n\
4943 as two scalar parameters. By default, GCC will attempt to pack complex\n\
4944 arguments into the target's word size. Some ABIs require complex arguments\n\
4945 to be split and treated as their individual components. For example, on\n\
4946 AIX64, complex floats should be passed in a pair of floating point\n\
4947 registers, even though a complex float would fit in one 64-bit floating\n\
4948 point register.\n\
4950 The default value of this hook is @code{NULL}, which is treated as always\n\
4951 false.",
4952 bool, (const_tree type), NULL)
4954 /* Return true if type T, mode MODE, may not be passed in registers,
4955 but must be passed on the stack. */
4956 /* ??? This predicate should be applied strictly after pass-by-reference.
4957 Need audit to verify that this is the case. */
4958 DEFHOOK
4959 (must_pass_in_stack,
4960 "This target hook should return @code{true} if we should not pass @var{arg}\n\
4961 solely in registers. The file @file{expr.h} defines a\n\
4962 definition that is usually appropriate, refer to @file{expr.h} for additional\n\
4963 documentation.",
4964 bool, (const function_arg_info &arg),
4965 must_pass_in_stack_var_size_or_pad)
4967 /* Return true if type TYPE, mode MODE, which is passed by reference,
4968 should have the object copy generated by the callee rather than
4969 the caller. It is never called for TYPE requiring constructors. */
4970 DEFHOOK
4971 (callee_copies,
4972 "The function argument described by the parameters to this hook is\n\
4973 known to be passed by reference. The hook should return true if the\n\
4974 function argument should be copied by the callee instead of copied\n\
4975 by the caller.\n\
4977 For any argument for which the hook returns true, if it can be\n\
4978 determined that the argument is not modified, then a copy need\n\
4979 not be generated.\n\
4981 The default version of this hook always returns false.",
4982 bool,
4983 (cumulative_args_t cum, const function_arg_info &arg),
4984 hook_bool_CUMULATIVE_ARGS_arg_info_false)
4986 /* Return zero for arguments passed entirely on the stack or entirely
4987 in registers. If passed in both, return the number of bytes passed
4988 in registers; the balance is therefore passed on the stack. */
4989 DEFHOOK
4990 (arg_partial_bytes,
4991 "This target hook returns the number of bytes at the beginning of an\n\
4992 argument that must be put in registers. The value must be zero for\n\
4993 arguments that are passed entirely in registers or that are entirely\n\
4994 pushed on the stack.\n\
4996 On some machines, certain arguments must be passed partially in\n\
4997 registers and partially in memory. On these machines, typically the\n\
4998 first few words of arguments are passed in registers, and the rest\n\
4999 on the stack. If a multi-word argument (a @code{double} or a\n\
5000 structure) crosses that boundary, its first few words must be passed\n\
5001 in registers and the rest must be pushed. This macro tells the\n\
5002 compiler when this occurs, and how many bytes should go in registers.\n\
5004 @code{TARGET_FUNCTION_ARG} for these arguments should return the first\n\
5005 register to be used by the caller for this argument; likewise\n\
5006 @code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.",
5007 int, (cumulative_args_t cum, const function_arg_info &arg),
5008 hook_int_CUMULATIVE_ARGS_arg_info_0)
5010 /* Update the state in CA to advance past an argument in the
5011 argument list. The values MODE, TYPE, and NAMED describe that
5012 argument. */
5013 DEFHOOK
5014 (function_arg_advance,
5015 "This hook updates the summarizer variable pointed to by @var{ca} to\n\
5016 advance past argument @var{arg} in the argument list. Once this is done,\n\
5017 the variable @var{cum} is suitable for analyzing the @emph{following}\n\
5018 argument with @code{TARGET_FUNCTION_ARG}, etc.\n\
5020 This hook need not do anything if the argument in question was passed\n\
5021 on the stack. The compiler knows how to track the amount of stack space\n\
5022 used for arguments without any special help.",
5023 void,
5024 (cumulative_args_t ca, const function_arg_info &arg),
5025 default_function_arg_advance)
5027 DEFHOOK
5028 (function_arg_offset,
5029 "This hook returns the number of bytes to add to the offset of an\n\
5030 argument of type @var{type} and mode @var{mode} when passed in memory.\n\
5031 This is needed for the SPU, which passes @code{char} and @code{short}\n\
5032 arguments in the preferred slot that is in the middle of the quad word\n\
5033 instead of starting at the top. The default implementation returns 0.",
5034 HOST_WIDE_INT, (machine_mode mode, const_tree type),
5035 default_function_arg_offset)
5037 DEFHOOK
5038 (function_arg_padding,
5039 "This hook determines whether, and in which direction, to pad out\n\
5040 an argument of mode @var{mode} and type @var{type}. It returns\n\
5041 @code{PAD_UPWARD} to insert padding above the argument, @code{PAD_DOWNWARD}\n\
5042 to insert padding below the argument, or @code{PAD_NONE} to inhibit padding.\n\
5044 The @emph{amount} of padding is not controlled by this hook, but by\n\
5045 @code{TARGET_FUNCTION_ARG_ROUND_BOUNDARY}. It is always just enough\n\
5046 to reach the next multiple of that boundary.\n\
5048 This hook has a default definition that is right for most systems.\n\
5049 For little-endian machines, the default is to pad upward. For\n\
5050 big-endian machines, the default is to pad downward for an argument of\n\
5051 constant size shorter than an @code{int}, and upward otherwise.",
5052 pad_direction, (machine_mode mode, const_tree type),
5053 default_function_arg_padding)
5055 /* Return zero if the argument described by the state of CA should
5056 be placed on a stack, or a hard register in which to store the
5057 argument. The values MODE, TYPE, and NAMED describe that
5058 argument. */
5059 DEFHOOK
5060 (function_arg,
5061 "Return an RTX indicating whether function argument @var{arg} is passed\n\
5062 in a register and if so, which register. Argument @var{ca} summarizes all\n\
5063 the previous arguments.\n\
5065 The return value is usually either a @code{reg} RTX for the hard\n\
5066 register in which to pass the argument, or zero to pass the argument\n\
5067 on the stack.\n\
5069 The value of the expression can also be a @code{parallel} RTX@. This is\n\
5070 used when an argument is passed in multiple locations. The mode of the\n\
5071 @code{parallel} should be the mode of the entire argument. The\n\
5072 @code{parallel} holds any number of @code{expr_list} pairs; each one\n\
5073 describes where part of the argument is passed. In each\n\
5074 @code{expr_list} the first operand must be a @code{reg} RTX for the hard\n\
5075 register in which to pass this part of the argument, and the mode of the\n\
5076 register RTX indicates how large this part of the argument is. The\n\
5077 second operand of the @code{expr_list} is a @code{const_int} which gives\n\
5078 the offset in bytes into the entire argument of where this part starts.\n\
5079 As a special exception the first @code{expr_list} in the @code{parallel}\n\
5080 RTX may have a first operand of zero. This indicates that the entire\n\
5081 argument is also stored on the stack.\n\
5083 The last time this hook is called, it is called with @code{MODE ==\n\
5084 VOIDmode}, and its result is passed to the @code{call} or @code{call_value}\n\
5085 pattern as operands 2 and 3 respectively.\n\
5087 @cindex @file{stdarg.h} and register arguments\n\
5088 The usual way to make the ISO library @file{stdarg.h} work on a\n\
5089 machine where some arguments are usually passed in registers, is to\n\
5090 cause nameless arguments to be passed on the stack instead. This is\n\
5091 done by making @code{TARGET_FUNCTION_ARG} return 0 whenever\n\
5092 @var{named} is @code{false}.\n\
5094 @cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}\n\
5095 @cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}\n\
5096 You may use the hook @code{targetm.calls.must_pass_in_stack}\n\
5097 in the definition of this macro to determine if this argument is of a\n\
5098 type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}\n\
5099 is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an\n\
5100 argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is\n\
5101 defined, the argument will be computed in the stack and then loaded into\n\
5102 a register.",
5103 rtx, (cumulative_args_t ca, const function_arg_info &arg),
5104 default_function_arg)
5106 DEFHOOK
5107 (function_incoming_arg,
5108 "Define this hook if the caller and callee on the target have different\n\
5109 views of where arguments are passed. Also define this hook if there are\n\
5110 functions that are never directly called, but are invoked by the hardware\n\
5111 and which have nonstandard calling conventions.\n\
5113 In this case @code{TARGET_FUNCTION_ARG} computes the register in\n\
5114 which the caller passes the value, and\n\
5115 @code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar\n\
5116 fashion to tell the function being called where the arguments will\n\
5117 arrive.\n\
5119 @code{TARGET_FUNCTION_INCOMING_ARG} can also return arbitrary address\n\
5120 computation using hard register, which can be forced into a register,\n\
5121 so that it can be used to pass special arguments.\n\
5123 If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,\n\
5124 @code{TARGET_FUNCTION_ARG} serves both purposes.",
5125 rtx, (cumulative_args_t ca, const function_arg_info &arg),
5126 default_function_incoming_arg)
5128 DEFHOOK
5129 (function_arg_boundary,
5130 "This hook returns the alignment boundary, in bits, of an argument\n\
5131 with the specified mode and type. The default hook returns\n\
5132 @code{PARM_BOUNDARY} for all arguments.",
5133 unsigned int, (machine_mode mode, const_tree type),
5134 default_function_arg_boundary)
5136 DEFHOOK
5137 (function_arg_round_boundary,
5138 "Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
5139 which is the default value for this hook. You can define this hook to\n\
5140 return a different value if an argument size must be rounded to a larger\n\
5141 value.",
5142 unsigned int, (machine_mode mode, const_tree type),
5143 default_function_arg_round_boundary)
5145 /* Return the diagnostic message string if function without a prototype
5146 is not allowed for this 'val' argument; NULL otherwise. */
5147 DEFHOOK
5148 (invalid_arg_for_unprototyped_fn,
5149 "If defined, this macro returns the diagnostic message when it is\n\
5150 illegal to pass argument @var{val} to function @var{funcdecl}\n\
5151 with prototype @var{typelist}.",
5152 const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
5153 hook_invalid_arg_for_unprototyped_fn)
5155 /* Return an rtx for the return value location of the function
5156 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
5157 DEFHOOK
5158 (function_value,
5159 "\n\
5160 Define this to return an RTX representing the place where a function\n\
5161 returns or receives a value of data type @var{ret_type}, a tree node\n\
5162 representing a data type. @var{fn_decl_or_type} is a tree node\n\
5163 representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a\n\
5164 function being called. If @var{outgoing} is false, the hook should\n\
5165 compute the register in which the caller will see the return value.\n\
5166 Otherwise, the hook should return an RTX representing the place where\n\
5167 a function returns a value.\n\
5169 On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.\n\
5170 (Actually, on most machines, scalar values are returned in the same\n\
5171 place regardless of mode.) The value of the expression is usually a\n\
5172 @code{reg} RTX for the hard register where the return value is stored.\n\
5173 The value can also be a @code{parallel} RTX, if the return value is in\n\
5174 multiple places. See @code{TARGET_FUNCTION_ARG} for an explanation of the\n\
5175 @code{parallel} form. Note that the callee will populate every\n\
5176 location specified in the @code{parallel}, but if the first element of\n\
5177 the @code{parallel} contains the whole return value, callers will use\n\
5178 that element as the canonical location and ignore the others. The m68k\n\
5179 port uses this type of @code{parallel} to return pointers in both\n\
5180 @samp{%a0} (the canonical location) and @samp{%d0}.\n\
5182 If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply\n\
5183 the same promotion rules specified in @code{PROMOTE_MODE} if\n\
5184 @var{valtype} is a scalar type.\n\
5186 If the precise function being called is known, @var{func} is a tree\n\
5187 node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null\n\
5188 pointer. This makes it possible to use a different value-returning\n\
5189 convention for specific functions when all their calls are\n\
5190 known.\n\
5192 Some target machines have ``register windows'' so that the register in\n\
5193 which a function returns its value is not the same as the one in which\n\
5194 the caller sees the value. For such machines, you should return\n\
5195 different RTX depending on @var{outgoing}.\n\
5197 @code{TARGET_FUNCTION_VALUE} is not used for return values with\n\
5198 aggregate data types, because these are returned in another way. See\n\
5199 @code{TARGET_STRUCT_VALUE_RTX} and related macros, below.",
5200 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
5201 default_function_value)
5203 /* Return the rtx for the result of a libcall of mode MODE,
5204 calling the function FN_NAME. */
5205 DEFHOOK
5206 (libcall_value,
5207 "Define this hook if the back-end needs to know the name of the libcall\n\
5208 function in order to determine where the result should be returned.\n\
5210 The mode of the result is given by @var{mode} and the name of the called\n\
5211 library function is given by @var{fun}. The hook should return an RTX\n\
5212 representing the place where the library function result will be returned.\n\
5214 If this hook is not defined, then LIBCALL_VALUE will be used.",
5215 rtx, (machine_mode mode, const_rtx fun),
5216 default_libcall_value)
5218 /* Return true if REGNO is a possible register number for
5219 a function value as seen by the caller. */
5220 DEFHOOK
5221 (function_value_regno_p,
5222 "A target hook that return @code{true} if @var{regno} is the number of a hard\n\
5223 register in which the values of called function may come back.\n\
5225 A register whose use for returning values is limited to serving as the\n\
5226 second of a pair (for a value of type @code{double}, say) need not be\n\
5227 recognized by this target hook.\n\
5229 If the machine has register windows, so that the caller and the called\n\
5230 function use different registers for the return value, this target hook\n\
5231 should recognize only the caller's register numbers.\n\
5233 If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.",
5234 bool, (const unsigned int regno),
5235 default_function_value_regno_p)
5237 DEFHOOK
5238 (fntype_abi,
5239 "Return the ABI used by a function with type @var{type}; see the\n\
5240 definition of @code{predefined_function_abi} for details of the ABI\n\
5241 descriptor. Targets only need to define this hook if they support\n\
5242 interoperability between several ABIs in the same translation unit.",
5243 const predefined_function_abi &, (const_tree type),
5244 NULL)
5246 DEFHOOK
5247 (insn_callee_abi,
5248 "This hook returns a description of the ABI used by the target of\n\
5249 call instruction @var{insn}; see the definition of\n\
5250 @code{predefined_function_abi} for details of the ABI descriptor.\n\
5251 Only the global function @code{insn_callee_abi} should call this hook\n\
5252 directly.\n\
5254 Targets only need to define this hook if they support\n\
5255 interoperability between several ABIs in the same translation unit.",
5256 const predefined_function_abi &, (const rtx_insn *insn),
5257 NULL)
5259 /* ??? Documenting this hook requires a GFDL license grant. */
5260 DEFHOOK_UNDOC
5261 (internal_arg_pointer,
5262 "Return an rtx for the argument pointer incoming to the\
5263 current function.",
5264 rtx, (void),
5265 default_internal_arg_pointer)
5267 /* Update the current function stack boundary if needed. */
5268 DEFHOOK
5269 (update_stack_boundary,
5270 "Define this macro to update the current function stack boundary if\n\
5271 necessary.",
5272 void, (void), NULL)
5274 /* Handle stack alignment and return an rtx for Dynamic Realign
5275 Argument Pointer if necessary. */
5276 DEFHOOK
5277 (get_drap_rtx,
5278 "This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a\n\
5279 different argument pointer register is needed to access the function's\n\
5280 argument list due to stack realignment. Return @code{NULL} if no DRAP\n\
5281 is needed.",
5282 rtx, (void), NULL)
5284 /* Generate instruction sequence to zero call used registers. */
5285 DEFHOOK
5286 (zero_call_used_regs,
5287 "This target hook emits instructions to zero the subset of @var{selected_regs}\n\
5288 that could conceivably contain values that are useful to an attacker.\n\
5289 Return the set of registers that were actually cleared.\n\
5291 For most targets, the returned set of registers is a subset of\n\
5292 @var{selected_regs}, however, for some of the targets (for example MIPS),\n\
5293 clearing some registers that are in the @var{selected_regs} requires\n\
5294 clearing other call used registers that are not in the @var{selected_regs},\n\
5295 under such situation, the returned set of registers must be a subset of all\n\
5296 call used registers.\n\
5298 The default implementation uses normal move instructions to zero\n\
5299 all the registers in @var{selected_regs}. Define this hook if the\n\
5300 target has more efficient ways of zeroing certain registers,\n\
5301 or if you believe that certain registers would never contain\n\
5302 values that are useful to an attacker.",
5303 HARD_REG_SET, (HARD_REG_SET selected_regs),
5304 default_zero_call_used_regs)
5306 /* Return true if all function parameters should be spilled to the
5307 stack. */
5308 DEFHOOK
5309 (allocate_stack_slots_for_args,
5310 "When optimization is disabled, this hook indicates whether or not\n\
5311 arguments should be allocated to stack slots. Normally, GCC allocates\n\
5312 stacks slots for arguments when not optimizing in order to make\n\
5313 debugging easier. However, when a function is declared with\n\
5314 @code{__attribute__((naked))}, there is no stack frame, and the compiler\n\
5315 cannot safely move arguments from the registers in which they are passed\n\
5316 to the stack. Therefore, this hook should return true in general, but\n\
5317 false for naked functions. The default implementation always returns true.",
5318 bool, (void),
5319 hook_bool_void_true)
5321 /* Return an rtx for the static chain for FNDECL_OR_TYPE. If INCOMING_P
5322 is true, then it should be for the callee; otherwise for the caller. */
5323 DEFHOOK
5324 (static_chain,
5325 "This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for\n\
5326 targets that may use different static chain locations for different\n\
5327 nested functions. This may be required if the target has function\n\
5328 attributes that affect the calling conventions of the function and\n\
5329 those calling conventions use different static chain locations.\n\
5331 The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.\n\
5333 If the static chain is passed in memory, this hook should be used to\n\
5334 provide rtx giving @code{mem} expressions that denote where they are stored.\n\
5335 Often the @code{mem} expression as seen by the caller will be at an offset\n\
5336 from the stack pointer and the @code{mem} expression as seen by the callee\n\
5337 will be at an offset from the frame pointer.\n\
5338 @findex stack_pointer_rtx\n\
5339 @findex frame_pointer_rtx\n\
5340 @findex arg_pointer_rtx\n\
5341 The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and\n\
5342 @code{arg_pointer_rtx} will have been initialized and should be used\n\
5343 to refer to those items.",
5344 rtx, (const_tree fndecl_or_type, bool incoming_p),
5345 default_static_chain)
5347 /* Fill in the trampoline at MEM with a call to FNDECL and a
5348 static chain value of CHAIN. */
5349 DEFHOOK
5350 (trampoline_init,
5351 "This hook is called to initialize a trampoline.\n\
5352 @var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}\n\
5353 is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an\n\
5354 RTX for the static chain value that should be passed to the function\n\
5355 when it is called.\n\
5357 If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the\n\
5358 first thing this hook should do is emit a block move into @var{m_tramp}\n\
5359 from the memory block returned by @code{assemble_trampoline_template}.\n\
5360 Note that the block move need only cover the constant parts of the\n\
5361 trampoline. If the target isolates the variable parts of the trampoline\n\
5362 to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.\n\
5364 If the target requires any other actions, such as flushing caches\n\
5365 (possibly calling function maybe_emit_call_builtin___clear_cache) or\n\
5366 enabling stack execution, these actions should be performed after\n\
5367 initializing the trampoline proper.",
5368 void, (rtx m_tramp, tree fndecl, rtx static_chain),
5369 default_trampoline_init)
5371 /* Emit a call to a function to clear the instruction cache. */
5372 DEFHOOK
5373 (emit_call_builtin___clear_cache,
5374 "On targets that do not define a @code{clear_cache} insn expander,\n\
5375 but that define the @code{CLEAR_CACHE_INSN} macro,\n\
5376 maybe_emit_call_builtin___clear_cache relies on this target hook\n\
5377 to clear an address range in the instruction cache.\n\
5379 The default implementation calls the @code{__clear_cache} builtin,\n\
5380 taking the assembler name from the builtin declaration. Overriding\n\
5381 definitions may call alternate functions, with alternate calling\n\
5382 conventions, or emit alternate RTX to perform the job.",
5383 void, (rtx begin, rtx end),
5384 default_emit_call_builtin___clear_cache)
5386 /* Adjust the address of the trampoline in a target-specific way. */
5387 DEFHOOK
5388 (trampoline_adjust_address,
5389 "This hook should perform any machine-specific adjustment in\n\
5390 the address of the trampoline. Its argument contains the address of the\n\
5391 memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}. In case\n\
5392 the address to be used for a function call should be different from the\n\
5393 address at which the template was stored, the different address should\n\
5394 be returned; otherwise @var{addr} should be returned unchanged.\n\
5395 If this hook is not defined, @var{addr} will be used for function calls.",
5396 rtx, (rtx addr), NULL)
5398 DEFHOOKPOD
5399 (custom_function_descriptors,
5400 "If the target can use GCC's generic descriptor mechanism for nested\n\
5401 functions, define this hook to a power of 2 representing an unused bit\n\
5402 in function pointers which can be used to differentiate descriptors at\n\
5403 run time. This value gives the number of bytes by which descriptor\n\
5404 pointers are misaligned compared to function pointers. For example, on\n\
5405 targets that require functions to be aligned to a 4-byte boundary, a\n\
5406 value of either 1 or 2 is appropriate unless the architecture already\n\
5407 reserves the bit for another purpose, such as on ARM.\n\
5409 Define this hook to 0 if the target implements ABI support for\n\
5410 function descriptors in its standard calling sequence, like for example\n\
5411 HPPA or IA-64.\n\
5413 Using descriptors for nested functions\n\
5414 eliminates the need for trampolines that reside on the stack and require\n\
5415 it to be made executable.",
5416 int, -1)
5418 /* Return the number of bytes of its own arguments that a function
5419 pops on returning, or 0 if the function pops no arguments and the
5420 caller must therefore pop them all after the function returns. */
5421 /* ??? tm.texi has no types for the parameters. */
5422 DEFHOOK
5423 (return_pops_args,
5424 "This target hook returns the number of bytes of its own arguments that\n\
5425 a function pops on returning, or 0 if the function pops no arguments\n\
5426 and the caller must therefore pop them all after the function returns.\n\
5428 @var{fundecl} is a C variable whose value is a tree node that describes\n\
5429 the function in question. Normally it is a node of type\n\
5430 @code{FUNCTION_DECL} that describes the declaration of the function.\n\
5431 From this you can obtain the @code{DECL_ATTRIBUTES} of the function.\n\
5433 @var{funtype} is a C variable whose value is a tree node that\n\
5434 describes the function in question. Normally it is a node of type\n\
5435 @code{FUNCTION_TYPE} that describes the data type of the function.\n\
5436 From this it is possible to obtain the data types of the value and\n\
5437 arguments (if known).\n\
5439 When a call to a library function is being considered, @var{fundecl}\n\
5440 will contain an identifier node for the library function. Thus, if\n\
5441 you need to distinguish among various library functions, you can do so\n\
5442 by their names. Note that ``library function'' in this context means\n\
5443 a function used to perform arithmetic, whose name is known specially\n\
5444 in the compiler and was not mentioned in the C code being compiled.\n\
5446 @var{size} is the number of bytes of arguments passed on the\n\
5447 stack. If a variable number of bytes is passed, it is zero, and\n\
5448 argument popping will always be the responsibility of the calling function.\n\
5450 On the VAX, all functions always pop their arguments, so the definition\n\
5451 of this macro is @var{size}. On the 68000, using the standard\n\
5452 calling convention, no functions pop their arguments, so the value of\n\
5453 the macro is always 0 in this case. But an alternative calling\n\
5454 convention is available in which functions that take a fixed number of\n\
5455 arguments pop them but other functions (such as @code{printf}) pop\n\
5456 nothing (the caller pops all). When this convention is in use,\n\
5457 @var{funtype} is examined to determine whether a function takes a fixed\n\
5458 number of arguments.",
5459 poly_int64, (tree fundecl, tree funtype, poly_int64 size),
5460 default_return_pops_args)
5462 /* Return a mode wide enough to copy any function value that might be
5463 returned. */
5464 DEFHOOK
5465 (get_raw_result_mode,
5466 "This target hook returns the mode to be used when accessing raw return\n\
5467 registers in @code{__builtin_return}. Define this macro if the value\n\
5468 in @var{reg_raw_mode} is not correct. Use @code{VOIDmode} if a register\n\
5469 should be ignored for @code{__builtin_return} purposes.",
5470 fixed_size_mode, (int regno),
5471 default_get_reg_raw_mode)
5473 /* Return a mode wide enough to copy any argument value that might be
5474 passed. */
5475 DEFHOOK
5476 (get_raw_arg_mode,
5477 "This target hook returns the mode to be used when accessing raw argument\n\
5478 registers in @code{__builtin_apply_args}. Define this macro if the value\n\
5479 in @var{reg_raw_mode} is not correct. Use @code{VOIDmode} if a register\n\
5480 should be ignored for @code{__builtin_apply_args} purposes.",
5481 fixed_size_mode, (int regno),
5482 default_get_reg_raw_mode)
5484 /* Return true if a type is an empty record. */
5485 DEFHOOK
5486 (empty_record_p,
5487 "This target hook returns true if the type is an empty record. The default\n\
5488 is to return @code{false}.",
5489 bool, (const_tree type),
5490 hook_bool_const_tree_false)
5492 /* Warn about the change in empty class parameter passing ABI. */
5493 DEFHOOK
5494 (warn_parameter_passing_abi,
5495 "This target hook warns about the change in empty class parameter passing\n\
5496 ABI.",
5497 void, (cumulative_args_t ca, tree type),
5498 hook_void_CUMULATIVE_ARGS_tree)
5500 HOOK_VECTOR_END (calls)
5502 DEFHOOK
5503 (use_pseudo_pic_reg,
5504 "This hook should return 1 in case pseudo register should be created\n\
5505 for pic_offset_table_rtx during function expand.",
5506 bool, (void),
5507 hook_bool_void_false)
5509 DEFHOOK
5510 (init_pic_reg,
5511 "Perform a target dependent initialization of pic_offset_table_rtx.\n\
5512 This hook is called at the start of register allocation.",
5513 void, (void),
5514 hook_void_void)
5516 /* Return the diagnostic message string if conversion from FROMTYPE
5517 to TOTYPE is not allowed, NULL otherwise. */
5518 DEFHOOK
5519 (invalid_conversion,
5520 "If defined, this macro returns the diagnostic message when it is\n\
5521 invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}\n\
5522 if validity should be determined by the front end.",
5523 const char *, (const_tree fromtype, const_tree totype),
5524 hook_constcharptr_const_tree_const_tree_null)
5526 /* Return the diagnostic message string if the unary operation OP is
5527 not permitted on TYPE, NULL otherwise. */
5528 DEFHOOK
5529 (invalid_unary_op,
5530 "If defined, this macro returns the diagnostic message when it is\n\
5531 invalid to apply operation @var{op} (where unary plus is denoted by\n\
5532 @code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}\n\
5533 if validity should be determined by the front end.",
5534 const char *, (int op, const_tree type),
5535 hook_constcharptr_int_const_tree_null)
5537 /* Return the diagnostic message string if the binary operation OP
5538 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
5539 DEFHOOK
5540 (invalid_binary_op,
5541 "If defined, this macro returns the diagnostic message when it is\n\
5542 invalid to apply operation @var{op} to operands of types @var{type1}\n\
5543 and @var{type2}, or @code{NULL} if validity should be determined by\n\
5544 the front end.",
5545 const char *, (int op, const_tree type1, const_tree type2),
5546 hook_constcharptr_int_const_tree_const_tree_null)
5548 /* If values of TYPE are promoted to some other type when used in
5549 expressions (analogous to the integer promotions), return that type,
5550 or NULL_TREE otherwise. */
5551 DEFHOOK
5552 (promoted_type,
5553 "If defined, this target hook returns the type to which values of\n\
5554 @var{type} should be promoted when they appear in expressions,\n\
5555 analogous to the integer promotions, or @code{NULL_TREE} to use the\n\
5556 front end's normal promotion rules. This hook is useful when there are\n\
5557 target-specific types with special promotion rules.\n\
5558 This is currently used only by the C and C++ front ends.",
5559 tree, (const_tree type),
5560 hook_tree_const_tree_null)
5562 /* Convert EXPR to TYPE, if target-specific types with special conversion
5563 rules are involved. Return the converted expression, or NULL to apply
5564 the standard conversion rules. */
5565 DEFHOOK
5566 (convert_to_type,
5567 "If defined, this hook returns the result of converting @var{expr} to\n\
5568 @var{type}. It should return the converted expression,\n\
5569 or @code{NULL_TREE} to apply the front end's normal conversion rules.\n\
5570 This hook is useful when there are target-specific types with special\n\
5571 conversion rules.\n\
5572 This is currently used only by the C and C++ front ends.",
5573 tree, (tree type, tree expr),
5574 hook_tree_tree_tree_null)
5576 DEFHOOK
5577 (verify_type_context,
5578 "If defined, this hook returns false if there is a target-specific reason\n\
5579 why type @var{type} cannot be used in the source language context described\n\
5580 by @var{context}. When @var{silent_p} is false, the hook also reports an\n\
5581 error against @var{loc} for invalid uses of @var{type}.\n\
5583 Calls to this hook should be made through the global function\n\
5584 @code{verify_type_context}, which makes the @var{silent_p} parameter\n\
5585 default to false and also handles @code{error_mark_node}.\n\
5587 The default implementation always returns true.",
5588 bool, (location_t loc, type_context_kind context, const_tree type,
5589 bool silent_p),
5590 NULL)
5592 DEFHOOK
5593 (can_change_mode_class,
5594 "This hook returns true if it is possible to bitcast values held in\n\
5595 registers of class @var{rclass} from mode @var{from} to mode @var{to}\n\
5596 and if doing so preserves the low-order bits that are common to both modes.\n\
5597 The result is only meaningful if @var{rclass} has registers that can hold\n\
5598 both @code{from} and @code{to}. The default implementation returns true.\n\
5600 As an example of when such bitcasting is invalid, loading 32-bit integer or\n\
5601 floating-point objects into floating-point registers on Alpha extends them\n\
5602 to 64 bits. Therefore loading a 64-bit object and then storing it as a\n\
5603 32-bit object does not store the low-order 32 bits, as would be the case\n\
5604 for a normal register. Therefore, @file{alpha.h} defines\n\
5605 @code{TARGET_CAN_CHANGE_MODE_CLASS} to return:\n\
5607 @smallexample\n\
5608 (GET_MODE_SIZE (from) == GET_MODE_SIZE (to)\n\
5609 || !reg_classes_intersect_p (FLOAT_REGS, rclass))\n\
5610 @end smallexample\n\
5612 Even if storing from a register in mode @var{to} would be valid,\n\
5613 if both @var{from} and @code{raw_reg_mode} for @var{rclass} are wider\n\
5614 than @code{word_mode}, then we must prevent @var{to} narrowing the\n\
5615 mode. This happens when the middle-end assumes that it can load\n\
5616 or store pieces of an @var{N}-word pseudo, and that the pseudo will\n\
5617 eventually be allocated to @var{N} @code{word_mode} hard registers.\n\
5618 Failure to prevent this kind of mode change will result in the\n\
5619 entire @code{raw_reg_mode} being modified instead of the partial\n\
5620 value that the middle-end intended.",
5621 bool, (machine_mode from, machine_mode to, reg_class_t rclass),
5622 hook_bool_mode_mode_reg_class_t_true)
5624 /* Change pseudo allocno class calculated by IRA. */
5625 DEFHOOK
5626 (ira_change_pseudo_allocno_class,
5627 "A target hook which can change allocno class for given pseudo from\n\
5628 allocno and best class calculated by IRA.\n\
5630 The default version of this target hook always returns given class.",
5631 reg_class_t, (int, reg_class_t, reg_class_t),
5632 default_ira_change_pseudo_allocno_class)
5634 /* Return true if we use LRA instead of reload. */
5635 DEFHOOK
5636 (lra_p,
5637 "A target hook which returns true if we use LRA instead of reload pass.\n\
5639 The default version of this target hook returns true. New ports\n\
5640 should use LRA, and existing ports are encouraged to convert.",
5641 bool, (void),
5642 default_lra_p)
5644 /* Return register priority of given hard regno for the current target. */
5645 DEFHOOK
5646 (register_priority,
5647 "A target hook which returns the register priority number to which the\n\
5648 register @var{hard_regno} belongs to. The bigger the number, the\n\
5649 more preferable the hard register usage (when all other conditions are\n\
5650 the same). This hook can be used to prefer some hard register over\n\
5651 others in LRA. For example, some x86-64 register usage needs\n\
5652 additional prefix which makes instructions longer. The hook can\n\
5653 return lower priority number for such registers make them less favorable\n\
5654 and as result making the generated code smaller.\n\
5656 The default version of this target hook returns always zero.",
5657 int, (int),
5658 default_register_priority)
5660 /* Return true if we need register usage leveling. */
5661 DEFHOOK
5662 (register_usage_leveling_p,
5663 "A target hook which returns true if we need register usage leveling.\n\
5664 That means if a few hard registers are equally good for the\n\
5665 assignment, we choose the least used hard register. The register\n\
5666 usage leveling may be profitable for some targets. Don't use the\n\
5667 usage leveling for targets with conditional execution or targets\n\
5668 with big register files as it hurts if-conversion and cross-jumping\n\
5669 optimizations.\n\
5671 The default version of this target hook returns always false.",
5672 bool, (void),
5673 default_register_usage_leveling_p)
5675 /* Return true if maximal address displacement can be different. */
5676 DEFHOOK
5677 (different_addr_displacement_p,
5678 "A target hook which returns true if an address with the same structure\n\
5679 can have different maximal legitimate displacement. For example, the\n\
5680 displacement can depend on memory mode or on operand combinations in\n\
5681 the insn.\n\
5683 The default version of this target hook returns always false.",
5684 bool, (void),
5685 default_different_addr_displacement_p)
5687 /* Determine class for spilling pseudos of given mode into registers
5688 instead of memory. */
5689 DEFHOOK
5690 (spill_class,
5691 "This hook defines a class of registers which could be used for spilling\n\
5692 pseudos of the given mode and class, or @code{NO_REGS} if only memory\n\
5693 should be used. Not defining this hook is equivalent to returning\n\
5694 @code{NO_REGS} for all inputs.",
5695 reg_class_t, (reg_class_t, machine_mode),
5696 NULL)
5698 /* Determine an additional allocno class. */
5699 DEFHOOK
5700 (additional_allocno_class_p,
5701 "This hook should return @code{true} if given class of registers should\n\
5702 be an allocno class in any way. Usually RA uses only one register\n\
5703 class from all classes containing the same register set. In some\n\
5704 complicated cases, you need to have two or more such classes as\n\
5705 allocno ones for RA correct work. Not defining this hook is\n\
5706 equivalent to returning @code{false} for all inputs.",
5707 bool, (reg_class_t),
5708 hook_bool_reg_class_t_false)
5710 DEFHOOK
5711 (cstore_mode,
5712 "This hook defines the machine mode to use for the boolean result of\n\
5713 conditional store patterns. The ICODE argument is the instruction code\n\
5714 for the cstore being performed. Not definiting this hook is the same\n\
5715 as accepting the mode encoded into operand 0 of the cstore expander\n\
5716 patterns.",
5717 scalar_int_mode, (enum insn_code icode),
5718 default_cstore_mode)
5720 /* This target hook allows the backend to compute the register pressure
5721 classes to use. */
5722 DEFHOOK
5723 (compute_pressure_classes,
5724 "A target hook which lets a backend compute the set of pressure classes to\n\
5725 be used by those optimization passes which take register pressure into\n\
5726 account, as opposed to letting IRA compute them. It returns the number of\n\
5727 register classes stored in the array @var{pressure_classes}.",
5728 int, (enum reg_class *pressure_classes), NULL)
5730 /* True if a structure, union or array with MODE containing FIELD should
5731 be accessed using BLKmode. */
5732 DEFHOOK
5733 (member_type_forces_blk,
5734 "Return true if a structure, union or array containing @var{field} should\n\
5735 be accessed using @code{BLKMODE}.\n\
5737 If @var{field} is the only field in the structure, @var{mode} is its\n\
5738 mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the\n\
5739 case where structures of one field would require the structure's mode to\n\
5740 retain the field's mode.\n\
5742 Normally, this is not needed.",
5743 bool, (const_tree field, machine_mode mode),
5744 default_member_type_forces_blk)
5746 /* See tree-ssa-math-opts.cc:divmod_candidate_p for conditions
5747 that gate the divod transform. */
5748 DEFHOOK
5749 (expand_divmod_libfunc,
5750 "Define this hook for enabling divmod transform if the port does not have\n\
5751 hardware divmod insn but defines target-specific divmod libfuncs.",
5752 void, (rtx libfunc, machine_mode mode, rtx op0, rtx op1, rtx *quot, rtx *rem),
5753 NULL)
5755 /* Return the class for a secondary reload, and fill in extra information. */
5756 DEFHOOK
5757 (secondary_reload,
5758 "Many machines have some registers that cannot be copied directly to or\n\
5759 from memory or even from other types of registers. An example is the\n\
5760 @samp{MQ} register, which on most machines, can only be copied to or\n\
5761 from general registers, but not memory. Below, we shall be using the\n\
5762 term 'intermediate register' when a move operation cannot be performed\n\
5763 directly, but has to be done by copying the source into the intermediate\n\
5764 register first, and then copying the intermediate register to the\n\
5765 destination. An intermediate register always has the same mode as\n\
5766 source and destination. Since it holds the actual value being copied,\n\
5767 reload might apply optimizations to re-use an intermediate register\n\
5768 and eliding the copy from the source when it can determine that the\n\
5769 intermediate register still holds the required value.\n\
5771 Another kind of secondary reload is required on some machines which\n\
5772 allow copying all registers to and from memory, but require a scratch\n\
5773 register for stores to some memory locations (e.g., those with symbolic\n\
5774 address on the RT, and those with certain symbolic address on the SPARC\n\
5775 when compiling PIC)@. Scratch registers need not have the same mode\n\
5776 as the value being copied, and usually hold a different value than\n\
5777 that being copied. Special patterns in the md file are needed to\n\
5778 describe how the copy is performed with the help of the scratch register;\n\
5779 these patterns also describe the number, register class(es) and mode(s)\n\
5780 of the scratch register(s).\n\
5782 In some cases, both an intermediate and a scratch register are required.\n\
5784 For input reloads, this target hook is called with nonzero @var{in_p},\n\
5785 and @var{x} is an rtx that needs to be copied to a register of class\n\
5786 @var{reload_class} in @var{reload_mode}. For output reloads, this target\n\
5787 hook is called with zero @var{in_p}, and a register of class @var{reload_class}\n\
5788 needs to be copied to rtx @var{x} in @var{reload_mode}.\n\
5790 If copying a register of @var{reload_class} from/to @var{x} requires\n\
5791 an intermediate register, the hook @code{secondary_reload} should\n\
5792 return the register class required for this intermediate register.\n\
5793 If no intermediate register is required, it should return NO_REGS.\n\
5794 If more than one intermediate register is required, describe the one\n\
5795 that is closest in the copy chain to the reload register.\n\
5797 If scratch registers are needed, you also have to describe how to\n\
5798 perform the copy from/to the reload register to/from this\n\
5799 closest intermediate register. Or if no intermediate register is\n\
5800 required, but still a scratch register is needed, describe the\n\
5801 copy from/to the reload register to/from the reload operand @var{x}.\n\
5803 You do this by setting @code{sri->icode} to the instruction code of a pattern\n\
5804 in the md file which performs the move. Operands 0 and 1 are the output\n\
5805 and input of this copy, respectively. Operands from operand 2 onward are\n\
5806 for scratch operands. These scratch operands must have a mode, and a\n\
5807 single-register-class\n\
5808 @c [later: or memory]\n\
5809 output constraint.\n\
5811 When an intermediate register is used, the @code{secondary_reload}\n\
5812 hook will be called again to determine how to copy the intermediate\n\
5813 register to/from the reload operand @var{x}, so your hook must also\n\
5814 have code to handle the register class of the intermediate operand.\n\
5816 @c [For later: maybe we'll allow multi-alternative reload patterns -\n\
5817 @c the port maintainer could name a mov<mode> pattern that has clobbers -\n\
5818 @c and match the constraints of input and output to determine the required\n\
5819 @c alternative. A restriction would be that constraints used to match\n\
5820 @c against reloads registers would have to be written as register class\n\
5821 @c constraints, or we need a new target macro / hook that tells us if an\n\
5822 @c arbitrary constraint can match an unknown register of a given class.\n\
5823 @c Such a macro / hook would also be useful in other places.]\n\
5826 @var{x} might be a pseudo-register or a @code{subreg} of a\n\
5827 pseudo-register, which could either be in a hard register or in memory.\n\
5828 Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is\n\
5829 in memory and the hard register number if it is in a register.\n\
5831 Scratch operands in memory (constraint @code{\"=m\"} / @code{\"=&m\"}) are\n\
5832 currently not supported. For the time being, you will have to continue\n\
5833 to use @code{TARGET_SECONDARY_MEMORY_NEEDED} for that purpose.\n\
5835 @code{copy_cost} also uses this target hook to find out how values are\n\
5836 copied. If you want it to include some extra cost for the need to allocate\n\
5837 (a) scratch register(s), set @code{sri->extra_cost} to the additional cost.\n\
5838 Or if two dependent moves are supposed to have a lower cost than the sum\n\
5839 of the individual moves due to expected fortuitous scheduling and/or special\n\
5840 forwarding logic, you can set @code{sri->extra_cost} to a negative amount.",
5841 reg_class_t,
5842 (bool in_p, rtx x, reg_class_t reload_class, machine_mode reload_mode,
5843 secondary_reload_info *sri),
5844 default_secondary_reload)
5846 DEFHOOK
5847 (secondary_memory_needed,
5848 "Certain machines have the property that some registers cannot be copied\n\
5849 to some other registers without using memory. Define this hook on\n\
5850 those machines to return true if objects of mode @var{m} in registers\n\
5851 of @var{class1} can only be copied to registers of class @var{class2} by\n\
5852 storing a register of @var{class1} into memory and loading that memory\n\
5853 location into a register of @var{class2}. The default definition returns\n\
5854 false for all inputs.",
5855 bool, (machine_mode mode, reg_class_t class1, reg_class_t class2),
5856 hook_bool_mode_reg_class_t_reg_class_t_false)
5858 DEFHOOK
5859 (secondary_memory_needed_mode,
5860 "If @code{TARGET_SECONDARY_MEMORY_NEEDED} tells the compiler to use memory\n\
5861 when moving between two particular registers of mode @var{mode},\n\
5862 this hook specifies the mode that the memory should have.\n\
5864 The default depends on @code{TARGET_LRA_P}. Without LRA, the default\n\
5865 is to use a word-sized mode for integral modes that are smaller than a\n\
5866 a word. This is right thing to do on most machines because it ensures\n\
5867 that all bits of the register are copied and prevents accesses to the\n\
5868 registers in a narrower mode, which some machines prohibit for\n\
5869 floating-point registers.\n\
5871 However, this default behavior is not correct on some machines, such as\n\
5872 the DEC Alpha, that store short integers in floating-point registers\n\
5873 differently than in integer registers. On those machines, the default\n\
5874 widening will not work correctly and you must define this hook to\n\
5875 suppress that widening in some cases. See the file @file{alpha.cc} for\n\
5876 details.\n\
5878 With LRA, the default is to use @var{mode} unmodified.",
5879 machine_mode, (machine_mode mode),
5880 default_secondary_memory_needed_mode)
5882 /* Given an rtx X being reloaded into a reg required to be in class CLASS,
5883 return the class of reg to actually use. */
5884 DEFHOOK
5885 (preferred_reload_class,
5886 "A target hook that places additional restrictions on the register class\n\
5887 to use when it is necessary to copy value @var{x} into a register in class\n\
5888 @var{rclass}. The value is a register class; perhaps @var{rclass}, or perhaps\n\
5889 another, smaller class.\n\
5891 The default version of this hook always returns value of @code{rclass} argument.\n\
5893 Sometimes returning a more restrictive class makes better code. For\n\
5894 example, on the 68000, when @var{x} is an integer constant that is in range\n\
5895 for a @samp{moveq} instruction, the value of this macro is always\n\
5896 @code{DATA_REGS} as long as @var{rclass} includes the data registers.\n\
5897 Requiring a data register guarantees that a @samp{moveq} will be used.\n\
5899 One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return\n\
5900 @var{rclass} is if @var{x} is a legitimate constant which cannot be\n\
5901 loaded into some register class. By returning @code{NO_REGS} you can\n\
5902 force @var{x} into a memory location. For example, rs6000 can load\n\
5903 immediate values into general-purpose registers, but does not have an\n\
5904 instruction for loading an immediate value into a floating-point\n\
5905 register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when\n\
5906 @var{x} is a floating-point constant. If the constant can't be loaded\n\
5907 into any kind of register, code generation will be better if\n\
5908 @code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead\n\
5909 of using @code{TARGET_PREFERRED_RELOAD_CLASS}.\n\
5911 If an insn has pseudos in it after register allocation, reload will go\n\
5912 through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}\n\
5913 to find the best one. Returning @code{NO_REGS}, in this case, makes\n\
5914 reload add a @code{!} in front of the constraint: the x86 back-end uses\n\
5915 this feature to discourage usage of 387 registers when math is done in\n\
5916 the SSE registers (and vice versa).",
5917 reg_class_t,
5918 (rtx x, reg_class_t rclass),
5919 default_preferred_reload_class)
5921 /* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
5922 input reloads. */
5923 DEFHOOK
5924 (preferred_output_reload_class,
5925 "Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of\n\
5926 input reloads.\n\
5928 The default version of this hook always returns value of @code{rclass}\n\
5929 argument.\n\
5931 You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage\n\
5932 reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.",
5933 reg_class_t,
5934 (rtx x, reg_class_t rclass),
5935 default_preferred_output_reload_class)
5937 DEFHOOK
5938 (select_early_remat_modes,
5939 "On some targets, certain modes cannot be held in registers around a\n\
5940 standard ABI call and are relatively expensive to spill to the stack.\n\
5941 The early rematerialization pass can help in such cases by aggressively\n\
5942 recomputing values after calls, so that they don't need to be spilled.\n\
5944 This hook returns the set of such modes by setting the associated bits\n\
5945 in @var{modes}. The default implementation selects no modes, which has\n\
5946 the effect of disabling the early rematerialization pass.",
5947 void, (sbitmap modes),
5948 default_select_early_remat_modes)
5950 DEFHOOK
5951 (class_likely_spilled_p,
5952 "A target hook which returns @code{true} if pseudos that have been assigned\n\
5953 to registers of class @var{rclass} would likely be spilled because\n\
5954 registers of @var{rclass} are needed for spill registers.\n\
5956 The default version of this target hook returns @code{true} if @var{rclass}\n\
5957 has exactly one register and @code{false} otherwise. On most machines, this\n\
5958 default should be used. For generally register-starved machines, such as\n\
5959 i386, or machines with right register constraints, such as SH, this hook\n\
5960 can be used to avoid excessive spilling.\n\
5962 This hook is also used by some of the global intra-procedural code\n\
5963 transformations to throtle code motion, to avoid increasing register\n\
5964 pressure.",
5965 bool, (reg_class_t rclass),
5966 default_class_likely_spilled_p)
5968 /* Return the maximum number of consecutive registers
5969 needed to represent mode MODE in a register of class RCLASS. */
5970 DEFHOOK
5971 (class_max_nregs,
5972 "A target hook returns the maximum number of consecutive registers\n\
5973 of class @var{rclass} needed to hold a value of mode @var{mode}.\n\
5975 This is closely related to the macro @code{TARGET_HARD_REGNO_NREGS}.\n\
5976 In fact, the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},\n\
5977 @var{mode})} target hook should be the maximum value of\n\
5978 @code{TARGET_HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}\n\
5979 values in the class @var{rclass}.\n\
5981 This target hook helps control the handling of multiple-word values\n\
5982 in the reload pass.\n\
5984 The default version of this target hook returns the size of @var{mode}\n\
5985 in words.",
5986 unsigned char, (reg_class_t rclass, machine_mode mode),
5987 default_class_max_nregs)
5989 DEFHOOK
5990 (preferred_rename_class,
5991 "A target hook that places additional preference on the register\n\
5992 class to use when it is necessary to rename a register in class\n\
5993 @var{rclass} to another class, or perhaps @var{NO_REGS}, if no\n\
5994 preferred register class is found or hook @code{preferred_rename_class}\n\
5995 is not implemented.\n\
5996 Sometimes returning a more restrictive class makes better code. For\n\
5997 example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\n\
5998 smaller than instructions using @code{GENERIC_REGS}. By returning\n\
5999 @code{LO_REGS} from @code{preferred_rename_class}, code size can\n\
6000 be reduced.",
6001 reg_class_t, (reg_class_t rclass),
6002 default_preferred_rename_class)
6004 /* This target hook allows the backend to avoid unsafe substitution
6005 during register allocation. */
6006 DEFHOOK
6007 (cannot_substitute_mem_equiv_p,
6008 "A target hook which returns @code{true} if @var{subst} can't\n\
6009 substitute safely pseudos with equivalent memory values during\n\
6010 register allocation.\n\
6011 The default version of this target hook returns @code{false}.\n\
6012 On most machines, this default should be used. For generally\n\
6013 machines with non orthogonal register usage for addressing, such\n\
6014 as SH, this hook can be used to avoid excessive spilling.",
6015 bool, (rtx subst),
6016 hook_bool_rtx_false)
6018 /* This target hook allows the backend to legitimize base plus
6019 displacement addressing. */
6020 DEFHOOK
6021 (legitimize_address_displacement,
6022 "This hook tries to split address offset @var{orig_offset} into\n\
6023 two parts: one that should be added to the base address to create\n\
6024 a local anchor point, and an additional offset that can be applied\n\
6025 to the anchor to address a value of mode @var{mode}. The idea is that\n\
6026 the local anchor could be shared by other accesses to nearby locations.\n\
6028 The hook returns true if it succeeds, storing the offset of the\n\
6029 anchor from the base in @var{offset1} and the offset of the final address\n\
6030 from the anchor in @var{offset2}. The default implementation returns false.",
6031 bool, (rtx *offset1, rtx *offset2, poly_int64 orig_offset, machine_mode mode),
6032 default_legitimize_address_displacement)
6034 /* This target hook allows the backend to perform additional
6035 processing while initializing for variable expansion. */
6036 DEFHOOK
6037 (expand_to_rtl_hook,
6038 "This hook is called just before expansion into rtl, allowing the target\n\
6039 to perform additional initializations or analysis before the expansion.\n\
6040 For example, the rs6000 port uses it to allocate a scratch stack slot\n\
6041 for use in copying SDmode values between memory and floating point\n\
6042 registers whenever the function being expanded has any SDmode\n\
6043 usage.",
6044 void, (void),
6045 hook_void_void)
6047 /* This target hook allows the backend to perform additional
6048 instantiations on rtx that are not actually in insns yet,
6049 but will be later. */
6050 DEFHOOK
6051 (instantiate_decls,
6052 "This hook allows the backend to perform additional instantiations on rtl\n\
6053 that are not actually in any insns yet, but will be later.",
6054 void, (void),
6055 hook_void_void)
6057 DEFHOOK
6058 (hard_regno_nregs,
6059 "This hook returns the number of consecutive hard registers, starting\n\
6060 at register number @var{regno}, required to hold a value of mode\n\
6061 @var{mode}. This hook must never return zero, even if a register\n\
6062 cannot hold the requested mode - indicate that with\n\
6063 @code{TARGET_HARD_REGNO_MODE_OK} and/or\n\
6064 @code{TARGET_CAN_CHANGE_MODE_CLASS} instead.\n\
6066 The default definition returns the number of words in @var{mode}.",
6067 unsigned int, (unsigned int regno, machine_mode mode),
6068 default_hard_regno_nregs)
6070 DEFHOOK
6071 (hard_regno_mode_ok,
6072 "This hook returns true if it is permissible to store a value\n\
6073 of mode @var{mode} in hard register number @var{regno} (or in several\n\
6074 registers starting with that one). The default definition returns true\n\
6075 unconditionally.\n\
6077 You need not include code to check for the numbers of fixed registers,\n\
6078 because the allocation mechanism considers them to be always occupied.\n\
6080 @cindex register pairs\n\
6081 On some machines, double-precision values must be kept in even/odd\n\
6082 register pairs. You can implement that by defining this hook to reject\n\
6083 odd register numbers for such modes.\n\
6085 The minimum requirement for a mode to be OK in a register is that the\n\
6086 @samp{mov@var{mode}} instruction pattern support moves between the\n\
6087 register and other hard register in the same class and that moving a\n\
6088 value into the register and back out not alter it.\n\
6090 Since the same instruction used to move @code{word_mode} will work for\n\
6091 all narrower integer modes, it is not necessary on any machine for\n\
6092 this hook to distinguish between these modes, provided you define\n\
6093 patterns @samp{movhi}, etc., to take advantage of this. This is\n\
6094 useful because of the interaction between @code{TARGET_HARD_REGNO_MODE_OK}\n\
6095 and @code{TARGET_MODES_TIEABLE_P}; it is very desirable for all integer\n\
6096 modes to be tieable.\n\
6098 Many machines have special registers for floating point arithmetic.\n\
6099 Often people assume that floating point machine modes are allowed only\n\
6100 in floating point registers. This is not true. Any registers that\n\
6101 can hold integers can safely @emph{hold} a floating point machine\n\
6102 mode, whether or not floating arithmetic can be done on it in those\n\
6103 registers. Integer move instructions can be used to move the values.\n\
6105 On some machines, though, the converse is true: fixed-point machine\n\
6106 modes may not go in floating registers. This is true if the floating\n\
6107 registers normalize any value stored in them, because storing a\n\
6108 non-floating value there would garble it. In this case,\n\
6109 @code{TARGET_HARD_REGNO_MODE_OK} should reject fixed-point machine modes in\n\
6110 floating registers. But if the floating registers do not automatically\n\
6111 normalize, if you can store any bit pattern in one and retrieve it\n\
6112 unchanged without a trap, then any machine mode may go in a floating\n\
6113 register, so you can define this hook to say so.\n\
6115 The primary significance of special floating registers is rather that\n\
6116 they are the registers acceptable in floating point arithmetic\n\
6117 instructions. However, this is of no concern to\n\
6118 @code{TARGET_HARD_REGNO_MODE_OK}. You handle it by writing the proper\n\
6119 constraints for those instructions.\n\
6121 On some machines, the floating registers are especially slow to access,\n\
6122 so that it is better to store a value in a stack frame than in such a\n\
6123 register if floating point arithmetic is not being done. As long as the\n\
6124 floating registers are not in class @code{GENERAL_REGS}, they will not\n\
6125 be used unless some pattern's constraint asks for one.",
6126 bool, (unsigned int regno, machine_mode mode),
6127 hook_bool_uint_mode_true)
6129 DEFHOOK
6130 (modes_tieable_p,
6131 "This hook returns true if a value of mode @var{mode1} is accessible\n\
6132 in mode @var{mode2} without copying.\n\
6134 If @code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode1})} and\n\
6135 @code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode2})} are always\n\
6136 the same for any @var{r}, then\n\
6137 @code{TARGET_MODES_TIEABLE_P (@var{mode1}, @var{mode2})}\n\
6138 should be true. If they differ for any @var{r}, you should define\n\
6139 this hook to return false unless some other mechanism ensures the\n\
6140 accessibility of the value in a narrower mode.\n\
6142 You should define this hook to return true in as many cases as\n\
6143 possible since doing so will allow GCC to perform better register\n\
6144 allocation. The default definition returns true unconditionally.",
6145 bool, (machine_mode mode1, machine_mode mode2),
6146 hook_bool_mode_mode_true)
6148 /* Return true if is OK to use a hard register REGNO as scratch register
6149 in peephole2. */
6150 DEFHOOK
6151 (hard_regno_scratch_ok,
6152 "This target hook should return @code{true} if it is OK to use a hard register\n\
6153 @var{regno} as scratch reg in peephole2.\n\
6155 One common use of this macro is to prevent using of a register that\n\
6156 is not saved by a prologue in an interrupt handler.\n\
6158 The default version of this hook always returns @code{true}.",
6159 bool, (unsigned int regno),
6160 default_hard_regno_scratch_ok)
6162 DEFHOOK
6163 (hard_regno_call_part_clobbered,
6164 "ABIs usually specify that calls must preserve the full contents\n\
6165 of a particular register, or that calls can alter any part of a\n\
6166 particular register. This information is captured by the target macro\n\
6167 @code{CALL_REALLY_USED_REGISTERS}. However, some ABIs specify that calls\n\
6168 must preserve certain bits of a particular register but can alter others.\n\
6169 This hook should return true if this applies to at least one of the\n\
6170 registers in @samp{(reg:@var{mode} @var{regno})}, and if as a result the\n\
6171 call would alter part of the @var{mode} value. For example, if a call\n\
6172 preserves the low 32 bits of a 64-bit hard register @var{regno} but can\n\
6173 clobber the upper 32 bits, this hook should return true for a 64-bit mode\n\
6174 but false for a 32-bit mode.\n\
6176 The value of @var{abi_id} comes from the @code{predefined_function_abi}\n\
6177 structure that describes the ABI of the call; see the definition of the\n\
6178 structure for more details. If (as is usual) the target uses the same ABI\n\
6179 for all functions in a translation unit, @var{abi_id} is always 0.\n\
6181 The default implementation returns false, which is correct\n\
6182 for targets that don't have partly call-clobbered registers.",
6183 bool, (unsigned int abi_id, unsigned int regno, machine_mode mode),
6184 hook_bool_uint_uint_mode_false)
6186 DEFHOOK
6187 (get_multilib_abi_name,
6188 "This hook returns name of multilib ABI name.",
6189 const char *, (void),
6190 hook_constcharptr_void_null)
6192 /* Return the smallest number of different values for which it is best to
6193 use a jump-table instead of a tree of conditional branches. */
6194 DEFHOOK
6195 (case_values_threshold,
6196 "This function return the smallest number of different values for which it\n\
6197 is best to use a jump-table instead of a tree of conditional branches.\n\
6198 The default is four for machines with a @code{casesi} instruction and\n\
6199 five otherwise. This is best for most machines.",
6200 unsigned int, (void),
6201 default_case_values_threshold)
6203 DEFHOOK
6204 (starting_frame_offset,
6205 "This hook returns the offset from the frame pointer to the first local\n\
6206 variable slot to be allocated. If @code{FRAME_GROWS_DOWNWARD}, it is the\n\
6207 offset to @emph{end} of the first slot allocated, otherwise it is the\n\
6208 offset to @emph{beginning} of the first slot allocated. The default\n\
6209 implementation returns 0.",
6210 HOST_WIDE_INT, (void),
6211 hook_hwi_void_0)
6213 /* Optional callback to advise the target to compute the frame layout. */
6214 DEFHOOK
6215 (compute_frame_layout,
6216 "This target hook is called once each time the frame layout needs to be\n\
6217 recalculated. The calculations can be cached by the target and can then\n\
6218 be used by @code{INITIAL_ELIMINATION_OFFSET} instead of re-computing the\n\
6219 layout on every invocation of that hook. This is particularly useful\n\
6220 for targets that have an expensive frame layout function. Implementing\n\
6221 this callback is optional.",
6222 void, (void),
6223 hook_void_void)
6225 /* Return true if a function must have and use a frame pointer. */
6226 DEFHOOK
6227 (frame_pointer_required,
6228 "This target hook should return @code{true} if a function must have and use\n\
6229 a frame pointer. This target hook is called in the reload pass. If its return\n\
6230 value is @code{true} the function will have a frame pointer.\n\
6232 This target hook can in principle examine the current function and decide\n\
6233 according to the facts, but on most machines the constant @code{false} or the\n\
6234 constant @code{true} suffices. Use @code{false} when the machine allows code\n\
6235 to be generated with no frame pointer, and doing so saves some time or space.\n\
6236 Use @code{true} when there is no possible advantage to avoiding a frame\n\
6237 pointer.\n\
6239 In certain cases, the compiler does not know how to produce valid code\n\
6240 without a frame pointer. The compiler recognizes those cases and\n\
6241 automatically gives the function a frame pointer regardless of what\n\
6242 @code{targetm.frame_pointer_required} returns. You don't need to worry about\n\
6243 them.\n\
6245 In a function that does not require a frame pointer, the frame pointer\n\
6246 register can be allocated for ordinary usage, unless you mark it as a\n\
6247 fixed register. See @code{FIXED_REGISTERS} for more information.\n\
6249 Default return value is @code{false}.",
6250 bool, (void),
6251 hook_bool_void_false)
6253 /* Returns true if the compiler is allowed to try to replace register number
6254 from-reg with register number to-reg. */
6255 DEFHOOK
6256 (can_eliminate,
6257 "This target hook should return @code{true} if the compiler is allowed to\n\
6258 try to replace register number @var{from_reg} with register number\n\
6259 @var{to_reg}. This target hook will usually be @code{true}, since most of the\n\
6260 cases preventing register elimination are things that the compiler already\n\
6261 knows about.\n\
6263 Default return value is @code{true}.",
6264 bool, (const int from_reg, const int to_reg),
6265 hook_bool_const_int_const_int_true)
6267 /* Modify any or all of fixed_regs, call_used_regs, global_regs,
6268 reg_names, and reg_class_contents to account of the vagaries of the
6269 target. */
6270 DEFHOOK
6271 (conditional_register_usage,
6272 "This hook may conditionally modify five variables\n\
6273 @code{fixed_regs}, @code{call_used_regs}, @code{global_regs},\n\
6274 @code{reg_names}, and @code{reg_class_contents}, to take into account\n\
6275 any dependence of these register sets on target flags. The first three\n\
6276 of these are of type @code{char []} (interpreted as boolean vectors).\n\
6277 @code{global_regs} is a @code{const char *[]}, and\n\
6278 @code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is\n\
6279 called, @code{fixed_regs}, @code{call_used_regs},\n\
6280 @code{reg_class_contents}, and @code{reg_names} have been initialized\n\
6281 from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},\n\
6282 @code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.\n\
6283 @code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},\n\
6284 @option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}\n\
6285 command options have been applied.\n\
6287 @cindex disabling certain registers\n\
6288 @cindex controlling register usage\n\
6289 If the usage of an entire class of registers depends on the target\n\
6290 flags, you may indicate this to GCC by using this macro to modify\n\
6291 @code{fixed_regs} and @code{call_used_regs} to 1 for each of the\n\
6292 registers in the classes which should not be used by GCC@. Also make\n\
6293 @code{define_register_constraint}s return @code{NO_REGS} for constraints\n\
6294 that shouldn't be used.\n\
6296 (However, if this class is not included in @code{GENERAL_REGS} and all\n\
6297 of the insn patterns whose constraints permit this class are\n\
6298 controlled by target switches, then GCC will automatically avoid using\n\
6299 these registers when the target switches are opposed to them.)",
6300 void, (void),
6301 hook_void_void)
6303 DEFHOOK
6304 (stack_clash_protection_alloca_probe_range,
6305 "Some targets have an ABI defined interval for which no probing needs to be done.\n\
6306 When a probe does need to be done this same interval is used as the probe distance\n\
6307 up when doing stack clash protection for alloca.\n\
6308 On such targets this value can be set to override the default probing up interval.\n\
6309 Define this variable to return nonzero if such a probe range is required or zero otherwise.\n\
6310 Defining this hook also requires your functions which make use of alloca to have at least 8 byes\n\
6311 of outgoing arguments. If this is not the case the stack will be corrupted.\n\
6312 You need not define this macro if it would always have the value zero.",
6313 HOST_WIDE_INT, (void),
6314 default_stack_clash_protection_alloca_probe_range)
6317 /* Functions specific to the C family of frontends. */
6318 #undef HOOK_PREFIX
6319 #define HOOK_PREFIX "TARGET_C_"
6320 HOOK_VECTOR (TARGET_C, c)
6322 /* ??? Documenting this hook requires a GFDL license grant. */
6323 DEFHOOK_UNDOC
6324 (mode_for_suffix,
6325 "Return machine mode for non-standard constant literal suffix @var{c},\
6326 or VOIDmode if non-standard suffixes are unsupported.",
6327 machine_mode, (char c),
6328 default_mode_for_suffix)
6330 DEFHOOK
6331 (excess_precision,
6332 "Return a value, with the same meaning as the C99 macro\n\
6333 @code{FLT_EVAL_METHOD} that describes which excess precision should be\n\
6334 applied. @var{type} is either @code{EXCESS_PRECISION_TYPE_IMPLICIT},\n\
6335 @code{EXCESS_PRECISION_TYPE_FAST},\n\
6336 @code{EXCESS_PRECISION_TYPE_STANDARD}, or\n\
6337 @code{EXCESS_PRECISION_TYPE_FLOAT16}. For\n\
6338 @code{EXCESS_PRECISION_TYPE_IMPLICIT}, the target should return which\n\
6339 precision and range operations will be implictly evaluated in regardless\n\
6340 of the excess precision explicitly added. For\n\
6341 @code{EXCESS_PRECISION_TYPE_STANDARD}, \n\
6342 @code{EXCESS_PRECISION_TYPE_FLOAT16}, and\n\
6343 @code{EXCESS_PRECISION_TYPE_FAST}, the target should return the\n\
6344 explicit excess precision that should be added depending on the\n\
6345 value set for @option{-fexcess-precision=@r{[}standard@r{|}fast@r{|}16@r{]}}.\n\
6346 Note that unpredictable explicit excess precision does not make sense,\n\
6347 so a target should never return @code{FLT_EVAL_METHOD_UNPREDICTABLE}\n\
6348 when @var{type} is @code{EXCESS_PRECISION_TYPE_STANDARD},\n\
6349 @code{EXCESS_PRECISION_TYPE_FLOAT16} or\n\
6350 @code{EXCESS_PRECISION_TYPE_FAST}.",
6351 enum flt_eval_method, (enum excess_precision_type type),
6352 default_excess_precision)
6354 /* Return true if _BitInt(N) is supported and fill details about it into
6355 *INFO. */
6356 DEFHOOK
6357 (bitint_type_info,
6358 "This target hook returns true if @code{_BitInt(@var{N})} is supported and\n\
6359 provides details on it. @code{_BitInt(@var{N})} is to be represented as\n\
6360 series of @code{info->abi_limb_mode}\n\
6361 @code{CEIL (@var{N}, GET_MODE_PRECISION (info->abi_limb_mode))} limbs,\n\
6362 ordered from least significant to most significant if\n\
6363 @code{!info->big_endian}, otherwise from most significant to least\n\
6364 significant. If @code{info->extended} is false, the bits above or equal to\n\
6365 @var{N} are undefined when stored in a register or memory, otherwise they\n\
6366 are zero or sign extended depending on if it is\n\
6367 @code{unsigned _BitInt(@var{N})} or one of @code{_BitInt(@var{N})} or\n\
6368 @code{signed _BitInt(@var{N})}. Alignment of the type is\n\
6369 @code{GET_MODE_ALIGNMENT (info->limb_mode)}.",
6370 bool, (int n, struct bitint_info *info),
6371 default_bitint_type_info)
6373 HOOK_VECTOR_END (c)
6375 /* Functions specific to the C++ frontend. */
6376 #undef HOOK_PREFIX
6377 #define HOOK_PREFIX "TARGET_CXX_"
6378 HOOK_VECTOR (TARGET_CXX, cxx)
6380 /* Return the integer type used for guard variables. */
6381 DEFHOOK
6382 (guard_type,
6383 "Define this hook to override the integer type used for guard variables.\n\
6384 These are used to implement one-time construction of static objects. The\n\
6385 default is long_long_integer_type_node.",
6386 tree, (void),
6387 default_cxx_guard_type)
6389 /* Return true if only the low bit of the guard should be tested. */
6390 DEFHOOK
6391 (guard_mask_bit,
6392 "This hook determines how guard variables are used. It should return\n\
6393 @code{false} (the default) if the first byte should be used. A return value of\n\
6394 @code{true} indicates that only the least significant bit should be used.",
6395 bool, (void),
6396 hook_bool_void_false)
6398 /* Returns the size of the array cookie for an array of type. */
6399 DEFHOOK
6400 (get_cookie_size,
6401 "This hook returns the size of the cookie to use when allocating an array\n\
6402 whose elements have the indicated @var{type}. Assumes that it is already\n\
6403 known that a cookie is needed. The default is\n\
6404 @code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the\n\
6405 IA64/Generic C++ ABI@.",
6406 tree, (tree type),
6407 default_cxx_get_cookie_size)
6409 /* Returns true if the element size should be stored in the array cookie. */
6410 DEFHOOK
6411 (cookie_has_size,
6412 "This hook should return @code{true} if the element size should be stored in\n\
6413 array cookies. The default is to return @code{false}.",
6414 bool, (void),
6415 hook_bool_void_false)
6417 /* Allows backends to perform additional processing when
6418 deciding if a class should be exported or imported. */
6419 DEFHOOK
6420 (import_export_class,
6421 "If defined by a backend this hook allows the decision made to export\n\
6422 class @var{type} to be overruled. Upon entry @var{import_export}\n\
6423 will contain 1 if the class is going to be exported, @minus{}1 if it is going\n\
6424 to be imported and 0 otherwise. This function should return the\n\
6425 modified value and perform any other actions necessary to support the\n\
6426 backend's targeted operating system.",
6427 int, (tree type, int import_export), NULL)
6429 /* Returns true if constructors and destructors return "this". */
6430 DEFHOOK
6431 (cdtor_returns_this,
6432 "This hook should return @code{true} if constructors and destructors return\n\
6433 the address of the object created/destroyed. The default is to return\n\
6434 @code{false}.",
6435 bool, (void),
6436 hook_bool_void_false)
6438 /* Returns true if the key method for a class can be an inline
6439 function, so long as it is not declared inline in the class
6440 itself. Returning true is the behavior required by the Itanium C++ ABI. */
6441 DEFHOOK
6442 (key_method_may_be_inline,
6443 "This hook returns true if the key method for a class (i.e., the method\n\
6444 which, if defined in the current translation unit, causes the virtual\n\
6445 table to be emitted) may be an inline function. Under the standard\n\
6446 Itanium C++ ABI the key method may be an inline function so long as\n\
6447 the function is not declared inline in the class definition. Under\n\
6448 some variants of the ABI, an inline function can never be the key\n\
6449 method. The default is to return @code{true}.",
6450 bool, (void),
6451 hook_bool_void_true)
6453 DEFHOOK
6454 (determine_class_data_visibility,
6455 "@var{decl} is a virtual table, virtual table table, typeinfo object,\n\
6456 or other similar implicit class data object that will be emitted with\n\
6457 external linkage in this translation unit. No ELF visibility has been\n\
6458 explicitly specified. If the target needs to specify a visibility\n\
6459 other than that of the containing class, use this hook to set\n\
6460 @code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
6461 void, (tree decl),
6462 hook_void_tree)
6464 /* Returns true (the default) if virtual tables and other
6465 similar implicit class data objects are always COMDAT if they
6466 have external linkage. If this hook returns false, then
6467 class data for classes whose virtual table will be emitted in
6468 only one translation unit will not be COMDAT. */
6469 DEFHOOK
6470 (class_data_always_comdat,
6471 "This hook returns true (the default) if virtual tables and other\n\
6472 similar implicit class data objects are always COMDAT if they have\n\
6473 external linkage. If this hook returns false, then class data for\n\
6474 classes whose virtual table will be emitted in only one translation\n\
6475 unit will not be COMDAT.",
6476 bool, (void),
6477 hook_bool_void_true)
6479 /* Returns true (the default) if the RTTI for the basic types,
6480 which is always defined in the C++ runtime, should be COMDAT;
6481 false if it should not be COMDAT. */
6482 DEFHOOK
6483 (library_rtti_comdat,
6484 "This hook returns true (the default) if the RTTI information for\n\
6485 the basic types which is defined in the C++ runtime should always\n\
6486 be COMDAT, false if it should not be COMDAT.",
6487 bool, (void),
6488 hook_bool_void_true)
6490 /* Returns true if __aeabi_atexit should be used to register static
6491 destructors. */
6492 DEFHOOK
6493 (use_aeabi_atexit,
6494 "This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)\n\
6495 should be used to register static destructors when @option{-fuse-cxa-atexit}\n\
6496 is in effect. The default is to return false to use @code{__cxa_atexit}.",
6497 bool, (void),
6498 hook_bool_void_false)
6500 /* Returns true if target may use atexit in the same manner as
6501 __cxa_atexit to register static destructors. */
6502 DEFHOOK
6503 (use_atexit_for_cxa_atexit,
6504 "This hook returns true if the target @code{atexit} function can be used\n\
6505 in the same manner as @code{__cxa_atexit} to register C++ static\n\
6506 destructors. This requires that @code{atexit}-registered functions in\n\
6507 shared libraries are run in the correct order when the libraries are\n\
6508 unloaded. The default is to return false.",
6509 bool, (void),
6510 hook_bool_void_false)
6512 DEFHOOK
6513 (adjust_class_at_definition,
6514 "@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\n\
6515 been defined. Use this hook to make adjustments to the class (eg, tweak\n\
6516 visibility or perform any other required target modifications).",
6517 void, (tree type),
6518 hook_void_tree)
6520 DEFHOOK
6521 (decl_mangling_context,
6522 "Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
6523 tree, (const_tree decl),
6524 hook_tree_const_tree_null)
6526 HOOK_VECTOR_END (cxx)
6528 /* Functions and data for emulated TLS support. */
6529 #undef HOOK_PREFIX
6530 #define HOOK_PREFIX "TARGET_EMUTLS_"
6531 HOOK_VECTOR (TARGET_EMUTLS, emutls)
6533 /* Name of the address and common functions. */
6534 DEFHOOKPOD
6535 (get_address,
6536 "Contains the name of the helper function that uses a TLS control\n\
6537 object to locate a TLS instance. The default causes libgcc's\n\
6538 emulated TLS helper function to be used.",
6539 const char *, "__builtin___emutls_get_address")
6541 DEFHOOKPOD
6542 (register_common,
6543 "Contains the name of the helper function that should be used at\n\
6544 program startup to register TLS objects that are implicitly\n\
6545 initialized to zero. If this is @code{NULL}, all TLS objects will\n\
6546 have explicit initializers. The default causes libgcc's emulated TLS\n\
6547 registration function to be used.",
6548 const char *, "__builtin___emutls_register_common")
6550 /* Prefixes for proxy variable and template. */
6551 DEFHOOKPOD
6552 (var_section,
6553 "Contains the name of the section in which TLS control variables should\n\
6554 be placed. The default of @code{NULL} allows these to be placed in\n\
6555 any section.",
6556 const char *, NULL)
6558 DEFHOOKPOD
6559 (tmpl_section,
6560 "Contains the name of the section in which TLS initializers should be\n\
6561 placed. The default of @code{NULL} allows these to be placed in any\n\
6562 section.",
6563 const char *, NULL)
6565 /* Prefixes for proxy variable and template. */
6566 DEFHOOKPOD
6567 (var_prefix,
6568 "Contains the prefix to be prepended to TLS control variable names.\n\
6569 The default of @code{NULL} uses a target-specific prefix.",
6570 const char *, NULL)
6572 DEFHOOKPOD
6573 (tmpl_prefix,
6574 "Contains the prefix to be prepended to TLS initializer objects. The\n\
6575 default of @code{NULL} uses a target-specific prefix.",
6576 const char *, NULL)
6578 /* Function to generate field definitions of the proxy variable. */
6579 DEFHOOK
6580 (var_fields,
6581 "Specifies a function that generates the FIELD_DECLs for a TLS control\n\
6582 object type. @var{type} is the RECORD_TYPE the fields are for and\n\
6583 @var{name} should be filled with the structure tag, if the default of\n\
6584 @code{__emutls_object} is unsuitable. The default creates a type suitable\n\
6585 for libgcc's emulated TLS function.",
6586 tree, (tree type, tree *name),
6587 default_emutls_var_fields)
6589 /* Function to initialize a proxy variable. */
6590 DEFHOOK
6591 (var_init,
6592 "Specifies a function that generates the CONSTRUCTOR to initialize a\n\
6593 TLS control object. @var{var} is the TLS control object, @var{decl}\n\
6594 is the TLS object and @var{tmpl_addr} is the address of the\n\
6595 initializer. The default initializes libgcc's emulated TLS control object.",
6596 tree, (tree var, tree decl, tree tmpl_addr),
6597 default_emutls_var_init)
6599 /* Whether we are allowed to alter the usual alignment of the
6600 proxy variable. */
6601 DEFHOOKPOD
6602 (var_align_fixed,
6603 "Specifies whether the alignment of TLS control variable objects is\n\
6604 fixed and should not be increased as some backends may do to optimize\n\
6605 single objects. The default is false.",
6606 bool, false)
6608 /* Whether we can emit debug information for TLS vars. */
6609 DEFHOOKPOD
6610 (debug_form_tls_address,
6611 "Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor\n\
6612 may be used to describe emulated TLS control objects.",
6613 bool, false)
6615 HOOK_VECTOR_END (emutls)
6617 #undef HOOK_PREFIX
6618 #define HOOK_PREFIX "TARGET_OPTION_"
6619 HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)
6621 /* Function to validate the attribute((target(...))) strings. If
6622 the option is validated, the hook should also fill in
6623 DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
6624 DEFHOOK
6625 (valid_attribute_p,
6626 "This hook is called to parse @code{attribute(target(\"...\"))}, which\n\
6627 allows setting target-specific options on individual functions.\n\
6628 These function-specific options may differ\n\
6629 from the options specified on the command line. The hook should return\n\
6630 @code{true} if the options are valid.\n\
6632 The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
6633 the function declaration to hold a pointer to a target-specific\n\
6634 @code{struct cl_target_option} structure.",
6635 bool, (tree fndecl, tree name, tree args, int flags),
6636 default_target_option_valid_attribute_p)
6638 /* Function to validate the attribute((target_version(...))) strings. If
6639 the option is validated, the hook should also fill in
6640 DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
6641 DEFHOOK
6642 (valid_version_attribute_p,
6643 "This hook is called to parse @code{attribute(target_version(\"...\"))},\n\
6644 which allows setting target-specific options on individual function versions.\n\
6645 These function-specific options may differ\n\
6646 from the options specified on the command line. The hook should return\n\
6647 @code{true} if the options are valid.\n\
6649 The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
6650 the function declaration to hold a pointer to a target-specific\n\
6651 @code{struct cl_target_option} structure.",
6652 bool, (tree fndecl, tree name, tree args, int flags),
6653 default_target_option_valid_version_attribute_p)
6655 /* Function to save any extra target state in the target options structure. */
6656 DEFHOOK
6657 (save,
6658 "This hook is called to save any additional target-specific information\n\
6659 in the @code{struct cl_target_option} structure for function-specific\n\
6660 options from the @code{struct gcc_options} structure.\n\
6661 @xref{Option file format}.",
6662 void, (struct cl_target_option *ptr, struct gcc_options *opts,
6663 struct gcc_options *opts_set), NULL)
6665 /* Function to restore any extra target state from the target options
6666 structure. */
6667 DEFHOOK
6668 (restore,
6669 "This hook is called to restore any additional target-specific\n\
6670 information in the @code{struct cl_target_option} structure for\n\
6671 function-specific options to the @code{struct gcc_options} structure.",
6672 void, (struct gcc_options *opts, struct gcc_options *opts_set,
6673 struct cl_target_option *ptr), NULL)
6675 /* Function to update target-specific option information after being
6676 streamed in. */
6677 DEFHOOK
6678 (post_stream_in,
6679 "This hook is called to update target-specific information in the\n\
6680 @code{struct cl_target_option} structure after it is streamed in from\n\
6681 LTO bytecode.",
6682 void, (struct cl_target_option *ptr), NULL)
6684 /* Function to print any extra target state from the target options
6685 structure. */
6686 DEFHOOK
6687 (print,
6688 "This hook is called to print any additional target-specific\n\
6689 information in the @code{struct cl_target_option} structure for\n\
6690 function-specific options.",
6691 void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)
6693 /* Function to parse arguments to be validated for #pragma target, and to
6694 change the state if the options are valid. If the first argument is
6695 NULL, the second argument specifies the default options to use. Return
6696 true if the options are valid, and set the current state. */
6697 DEFHOOK
6698 (pragma_parse,
6699 "This target hook parses the options for @code{#pragma GCC target}, which\n\
6700 sets the target-specific options for functions that occur later in the\n\
6701 input stream. The options accepted should be the same as those handled by the\n\
6702 @code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.",
6703 bool, (tree args, tree pop_target),
6704 default_target_option_pragma_parse)
6706 /* Do option overrides for the target. */
6707 DEFHOOK
6708 (override,
6709 "Sometimes certain combinations of command options do not make sense on\n\
6710 a particular target machine. You can override the hook\n\
6711 @code{TARGET_OPTION_OVERRIDE} to take account of this. This hooks is called\n\
6712 once just after all the command options have been parsed.\n\
6714 Don't use this hook to turn on various extra optimizations for\n\
6715 @option{-O}. That is what @code{TARGET_OPTION_OPTIMIZATION} is for.\n\
6717 If you need to do something whenever the optimization level is\n\
6718 changed via the optimize attribute or pragma, see\n\
6719 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}",
6720 void, (void),
6721 hook_void_void)
6723 /* This function returns true if DECL1 and DECL2 are versions of the same
6724 function. DECL1 and DECL2 are function versions if and only if they
6725 have the same function signature and different target specific attributes,
6726 that is, they are compiled for different target machines. */
6727 DEFHOOK
6728 (function_versions,
6729 "This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are\n\
6730 versions of the same function. @var{DECL1} and @var{DECL2} are function\n\
6731 versions if and only if they have the same function signature and\n\
6732 different target specific attributes, that is, they are compiled for\n\
6733 different target machines.",
6734 bool, (tree decl1, tree decl2),
6735 hook_bool_tree_tree_false)
6737 /* Function to determine if one function can inline another function. */
6738 #undef HOOK_PREFIX
6739 #define HOOK_PREFIX "TARGET_"
6740 DEFHOOK
6741 (can_inline_p,
6742 "This target hook returns @code{false} if the @var{caller} function\n\
6743 cannot inline @var{callee}, based on target specific information. By\n\
6744 default, inlining is not allowed if the callee function has function\n\
6745 specific target options and the caller does not use the same options.",
6746 bool, (tree caller, tree callee),
6747 default_target_can_inline_p)
6749 DEFHOOK
6750 (update_ipa_fn_target_info,
6751 "Allow target to analyze all gimple statements for the given function to\n\
6752 record and update some target specific information for inlining. A typical\n\
6753 example is that a caller with one isa feature disabled is normally not\n\
6754 allowed to inline a callee with that same isa feature enabled even which is\n\
6755 attributed by always_inline, but with the conservative analysis on all\n\
6756 statements of the callee if we are able to guarantee the callee does not\n\
6757 exploit any instructions from the mismatch isa feature, it would be safe to\n\
6758 allow the caller to inline the callee.\n\
6759 @var{info} is one @code{unsigned int} value to record information in which\n\
6760 one set bit indicates one corresponding feature is detected in the analysis,\n\
6761 @var{stmt} is the statement being analyzed. Return true if target still\n\
6762 need to analyze the subsequent statements, otherwise return false to stop\n\
6763 subsequent analysis.\n\
6764 The default version of this hook returns false.",
6765 bool, (unsigned int& info, const gimple* stmt),
6766 default_update_ipa_fn_target_info)
6768 DEFHOOK
6769 (need_ipa_fn_target_info,
6770 "Allow target to check early whether it is necessary to analyze all gimple\n\
6771 statements in the given function to update target specific information for\n\
6772 inlining. See hook @code{update_ipa_fn_target_info} for usage example of\n\
6773 target specific information. This hook is expected to be invoked ahead of\n\
6774 the iterating with hook @code{update_ipa_fn_target_info}.\n\
6775 @var{decl} is the function being analyzed, @var{info} is the same as what\n\
6776 in hook @code{update_ipa_fn_target_info}, target can do one time update\n\
6777 into @var{info} without iterating for some case. Return true if target\n\
6778 decides to analyze all gimple statements to collect information, otherwise\n\
6779 return false.\n\
6780 The default version of this hook returns false.",
6781 bool, (const_tree decl, unsigned int& info),
6782 default_need_ipa_fn_target_info)
6784 DEFHOOK
6785 (relayout_function,
6786 "This target hook fixes function @var{fndecl} after attributes are processed.\n\
6787 Default does nothing. On ARM, the default function's alignment is updated\n\
6788 with the attribute target.",
6789 void, (tree fndecl),
6790 hook_void_tree)
6792 HOOK_VECTOR_END (target_option)
6794 /* For targets that need to mark extra registers as live on entry to
6795 the function, they should define this target hook and set their
6796 bits in the bitmap passed in. */
6797 DEFHOOK
6798 (extra_live_on_entry,
6799 "Add any hard registers to @var{regs} that are live on entry to the\n\
6800 function. This hook only needs to be defined to provide registers that\n\
6801 cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved\n\
6802 registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,\n\
6803 TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,\n\
6804 FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.",
6805 void, (bitmap regs),
6806 hook_void_bitmap)
6808 /* Targets should define this target hook to mark that non-callee clobbers are
6809 present in CALL_INSN_FUNCTION_USAGE for all the calls that bind to a local
6810 definition. */
6811 DEFHOOKPOD
6812 (call_fusage_contains_non_callee_clobbers,
6813 "Set to true if each call that binds to a local definition explicitly\n\
6814 clobbers or sets all non-fixed registers modified by performing the call.\n\
6815 That is, by the call pattern itself, or by code that might be inserted by the\n\
6816 linker (e.g.@: stubs, veneers, branch islands), but not including those\n\
6817 modifiable by the callee. The affected registers may be mentioned explicitly\n\
6818 in the call pattern, or included as clobbers in CALL_INSN_FUNCTION_USAGE.\n\
6819 The default version of this hook is set to false. The purpose of this hook\n\
6820 is to enable the fipa-ra optimization.",
6821 bool,
6822 false)
6824 /* Fill in additional registers set up by prologue into a regset. */
6825 DEFHOOK
6826 (set_up_by_prologue,
6827 "This hook should add additional registers that are computed by the prologue\n\
6828 to the hard regset for shrink-wrapping optimization purposes.",
6829 void, (struct hard_reg_set_container *),
6830 NULL)
6832 /* For targets that have attributes that can affect whether a
6833 function's return statements need checking. For instance a 'naked'
6834 function attribute. */
6835 DEFHOOK
6836 (warn_func_return,
6837 "True if a function's return statements should be checked for matching\n\
6838 the function's return type. This includes checking for falling off the end\n\
6839 of a non-void function. Return false if no such check should be made.",
6840 bool, (tree),
6841 hook_bool_tree_true)
6843 #undef HOOK_PREFIX
6844 #define HOOK_PREFIX "TARGET_SHRINK_WRAP_"
6845 HOOK_VECTOR (TARGET_SHRINK_WRAP_HOOKS, shrink_wrap)
6847 DEFHOOK
6848 (get_separate_components,
6849 "This hook should return an @code{sbitmap} with the bits set for those\n\
6850 components that can be separately shrink-wrapped in the current function.\n\
6851 Return @code{NULL} if the current function should not get any separate\n\
6852 shrink-wrapping.\n\
6853 Don't define this hook if it would always return @code{NULL}.\n\
6854 If it is defined, the other hooks in this group have to be defined as well.",
6855 sbitmap, (void),
6856 NULL)
6858 DEFHOOK
6859 (components_for_bb,
6860 "This hook should return an @code{sbitmap} with the bits set for those\n\
6861 components where either the prologue component has to be executed before\n\
6862 the @code{basic_block}, or the epilogue component after it, or both.",
6863 sbitmap, (basic_block),
6864 NULL)
6866 DEFHOOK
6867 (disqualify_components,
6868 "This hook should clear the bits in the @var{components} bitmap for those\n\
6869 components in @var{edge_components} that the target cannot handle on edge\n\
6870 @var{e}, where @var{is_prologue} says if this is for a prologue or an\n\
6871 epilogue instead.",
6872 void, (sbitmap components, edge e, sbitmap edge_components, bool is_prologue),
6873 NULL)
6875 DEFHOOK
6876 (emit_prologue_components,
6877 "Emit prologue insns for the components indicated by the parameter.",
6878 void, (sbitmap),
6879 NULL)
6881 DEFHOOK
6882 (emit_epilogue_components,
6883 "Emit epilogue insns for the components indicated by the parameter.",
6884 void, (sbitmap),
6885 NULL)
6887 DEFHOOK
6888 (set_handled_components,
6889 "Mark the components in the parameter as handled, so that the\n\
6890 @code{prologue} and @code{epilogue} named patterns know to ignore those\n\
6891 components. The target code should not hang on to the @code{sbitmap}, it\n\
6892 will be deleted after this call.",
6893 void, (sbitmap),
6894 NULL)
6896 HOOK_VECTOR_END (shrink_wrap)
6897 #undef HOOK_PREFIX
6898 #define HOOK_PREFIX "TARGET_"
6900 /* Determine the type of unwind info to emit for debugging. */
6901 DEFHOOK
6902 (debug_unwind_info,
6903 "This hook defines the mechanism that will be used for describing frame\n\
6904 unwind information to the debugger. Normally the hook will return\n\
6905 @code{UI_DWARF2} if DWARF 2 debug information is enabled, and\n\
6906 return @code{UI_NONE} otherwise.\n\
6908 A target may return @code{UI_DWARF2} even when DWARF 2 debug information\n\
6909 is disabled in order to always output DWARF 2 frame information.\n\
6911 A target may return @code{UI_TARGET} if it has ABI specified unwind tables.\n\
6912 This will suppress generation of the normal debug frame unwind information.",
6913 enum unwind_info_type, (void),
6914 default_debug_unwind_info)
6916 DEFHOOK
6917 (reset_location_view,
6918 "This hook, if defined, enables -ginternal-reset-location-views, and\n\
6919 uses its result to override cases in which the estimated min insn\n\
6920 length might be nonzero even when a PC advance (i.e., a view reset)\n\
6921 cannot be taken for granted.\n\
6923 If the hook is defined, it must return a positive value to indicate\n\
6924 the insn definitely advances the PC, and so the view number can be\n\
6925 safely assumed to be reset; a negative value to mean the insn\n\
6926 definitely does not advance the PC, and os the view number must not\n\
6927 be reset; or zero to decide based on the estimated insn length.\n\
6929 If insn length is to be regarded as reliable, set the hook to\n\
6930 @code{hook_int_rtx_insn_0}.",
6931 int, (rtx_insn *), NULL)
6933 /* The code parameter should be of type enum rtx_code but this is not
6934 defined at this time. */
6935 DEFHOOK
6936 (canonicalize_comparison,
6937 "On some machines not all possible comparisons are defined, but you can\n\
6938 convert an invalid comparison into a valid one. For example, the Alpha\n\
6939 does not have a @code{GT} comparison, but you can use an @code{LT}\n\
6940 comparison instead and swap the order of the operands.\n\
6942 On such machines, implement this hook to do any required conversions.\n\
6943 @var{code} is the initial comparison code and @var{op0} and @var{op1}\n\
6944 are the left and right operands of the comparison, respectively. If\n\
6945 @var{op0_preserve_value} is @code{true} the implementation is not\n\
6946 allowed to change the value of @var{op0} since the value might be used\n\
6947 in RTXs which aren't comparisons. E.g. the implementation is not\n\
6948 allowed to swap operands in that case.\n\
6950 GCC will not assume that the comparison resulting from this macro is\n\
6951 valid but will see if the resulting insn matches a pattern in the\n\
6952 @file{md} file.\n\
6954 You need not to implement this hook if it would never change the\n\
6955 comparison code or operands.",
6956 void, (int *code, rtx *op0, rtx *op1, bool op0_preserve_value),
6957 default_canonicalize_comparison)
6959 DEFHOOK
6960 (min_arithmetic_precision,
6961 "On some RISC architectures with 64-bit registers, the processor also\n\
6962 maintains 32-bit condition codes that make it possible to do real 32-bit\n\
6963 arithmetic, although the operations are performed on the full registers.\n\
6965 On such architectures, defining this hook to 32 tells the compiler to try\n\
6966 using 32-bit arithmetical operations setting the condition codes instead\n\
6967 of doing full 64-bit arithmetic.\n\
6969 More generally, define this hook on RISC architectures if you want the\n\
6970 compiler to try using arithmetical operations setting the condition codes\n\
6971 with a precision lower than the word precision.\n\
6973 You need not define this hook if @code{WORD_REGISTER_OPERATIONS} is not\n\
6974 defined to 1.",
6975 unsigned int, (void), default_min_arithmetic_precision)
6977 DEFHOOKPOD
6978 (atomic_test_and_set_trueval,
6979 "This value should be set if the result written by\n\
6980 @code{atomic_test_and_set} is not exactly 1, i.e.@: the\n\
6981 @code{bool} @code{true}.",
6982 unsigned char, 1)
6984 /* Return an unsigned int representing the alignment (in bits) of the atomic
6985 type which maps to machine MODE. This allows alignment to be overridden
6986 as needed. */
6987 DEFHOOK
6988 (atomic_align_for_mode,
6989 "If defined, this function returns an appropriate alignment in bits for an\n\
6990 atomic object of machine_mode @var{mode}. If 0 is returned then the\n\
6991 default alignment for the specified mode is used.",
6992 unsigned int, (machine_mode mode),
6993 hook_uint_mode_0)
6995 DEFHOOK
6996 (atomic_assign_expand_fenv,
6997 "ISO C11 requires atomic compound assignments that may raise floating-point\n\
6998 exceptions to raise exceptions corresponding to the arithmetic operation\n\
6999 whose result was successfully stored in a compare-and-exchange sequence.\n\
7000 This requires code equivalent to calls to @code{feholdexcept},\n\
7001 @code{feclearexcept} and @code{feupdateenv} to be generated at\n\
7002 appropriate points in the compare-and-exchange sequence. This hook should\n\
7003 set @code{*@var{hold}} to an expression equivalent to the call to\n\
7004 @code{feholdexcept}, @code{*@var{clear}} to an expression equivalent to\n\
7005 the call to @code{feclearexcept} and @code{*@var{update}} to an expression\n\
7006 equivalent to the call to @code{feupdateenv}. The three expressions are\n\
7007 @code{NULL_TREE} on entry to the hook and may be left as @code{NULL_TREE}\n\
7008 if no code is required in a particular place. The default implementation\n\
7009 leaves all three expressions as @code{NULL_TREE}. The\n\
7010 @code{__atomic_feraiseexcept} function from @code{libatomic} may be of use\n\
7011 as part of the code generated in @code{*@var{update}}.",
7012 void, (tree *hold, tree *clear, tree *update),
7013 default_atomic_assign_expand_fenv)
7015 /* Leave the boolean fields at the end. */
7017 /* True if we can create zeroed data by switching to a BSS section
7018 and then using ASM_OUTPUT_SKIP to allocate the space. */
7019 DEFHOOKPOD
7020 (have_switchable_bss_sections,
7021 "This flag is true if we can create zeroed data by switching to a BSS\n\
7022 section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.\n\
7023 This is true on most ELF targets.",
7024 bool, false)
7026 /* True if "native" constructors and destructors are supported,
7027 false if we're using collect2 for the job. */
7028 DEFHOOKPOD
7029 (have_ctors_dtors,
7030 "This value is true if the target supports some ``native'' method of\n\
7031 collecting constructors and destructors to be run at startup and exit.\n\
7032 It is false if we must use @command{collect2}.",
7033 bool, false)
7035 /* True if the target wants DTORs to be run from cxa_atexit. */
7036 DEFHOOKPOD
7037 (dtors_from_cxa_atexit,
7038 "This value is true if the target wants destructors to be queued to be\n\
7039 run from __cxa_atexit. If this is the case then, for each priority level,\n\
7040 a new constructor will be entered that registers the destructors for that\n\
7041 level with __cxa_atexit (and there will be no destructors emitted).\n\
7042 It is false the method implied by @code{have_ctors_dtors} is used.",
7043 bool, false)
7045 /* True if thread-local storage is supported. */
7046 DEFHOOKPOD
7047 (have_tls,
7048 "Contains the value true if the target supports thread-local storage.\n\
7049 The default value is false.",
7050 bool, false)
7052 /* True if a small readonly data section is supported. */
7053 DEFHOOKPOD
7054 (have_srodata_section,
7055 "Contains the value true if the target places read-only\n\
7056 ``small data'' into a separate section. The default value is false.",
7057 bool, false)
7059 /* True if EH frame info sections should be zero-terminated. */
7060 DEFHOOKPOD
7061 (terminate_dw2_eh_frame_info,
7062 "Contains the value true if the target should add a zero word onto the\n\
7063 end of a Dwarf-2 frame info section when used for exception handling.\n\
7064 Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and\n\
7065 true otherwise.",
7066 bool, true)
7068 /* True if #NO_APP should be emitted at the beginning of assembly output. */
7069 DEFHOOKPOD
7070 (asm_file_start_app_off,
7071 "If this flag is true, the text of the macro @code{ASM_APP_OFF} will be\n\
7072 printed as the very first line in the assembly file, unless\n\
7073 @option{-fverbose-asm} is in effect. (If that macro has been defined\n\
7074 to the empty string, this variable has no effect.) With the normal\n\
7075 definition of @code{ASM_APP_OFF}, the effect is to notify the GNU\n\
7076 assembler that it need not bother stripping comments or extra\n\
7077 whitespace from its input. This allows it to work a bit faster.\n\
7079 The default is false. You should not set it to true unless you have\n\
7080 verified that your port does not generate any extra whitespace or\n\
7081 comments that will cause GAS to issue errors in NO_APP mode.",
7082 bool, false)
7084 /* True if output_file_directive should be called for main_input_filename
7085 at the beginning of assembly output. */
7086 DEFHOOKPOD
7087 (asm_file_start_file_directive,
7088 "If this flag is true, @code{output_file_directive} will be called\n\
7089 for the primary source file, immediately after printing\n\
7090 @code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect\n\
7091 this to be done. The default is false.",
7092 bool, false)
7094 /* Returns true if we should generate exception tables for use with the
7095 ARM EABI. The effects the encoding of function exception specifications. */
7096 DEFHOOKPOD
7097 (arm_eabi_unwinder,
7098 "This flag should be set to @code{true} on targets that use an ARM EABI\n\
7099 based unwinding library, and @code{false} on other targets. This effects\n\
7100 the format of unwinding tables, and how the unwinder in entered after\n\
7101 running a cleanup. The default is @code{false}.",
7102 bool, false)
7104 DEFHOOKPOD
7105 (want_debug_pub_sections,
7106 "True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\n\
7107 should be emitted. These sections are not used on most platforms, and\n\
7108 in particular GDB does not use them.",
7109 bool, false)
7111 DEFHOOKPOD
7112 (delay_sched2,
7113 "True if sched2 is not to be run at its normal place.\n\
7114 This usually means it will be run as part of machine-specific reorg.",
7115 bool, false)
7117 DEFHOOKPOD
7118 (delay_vartrack,
7119 "True if vartrack is not to be run at its normal place.\n\
7120 This usually means it will be run as part of machine-specific reorg.",
7121 bool, false)
7123 DEFHOOKPOD
7124 (no_register_allocation,
7125 "True if register allocation and the passes\n\
7126 following it should not be run. Usually true only for virtual assembler\n\
7127 targets.",
7128 bool, false)
7130 /* Leave the boolean fields at the end. */
7132 /* Functions related to mode switching. */
7133 #undef HOOK_PREFIX
7134 #define HOOK_PREFIX "TARGET_MODE_"
7135 HOOK_VECTOR (TARGET_TOGGLE_, mode_switching)
7137 DEFHOOK
7138 (emit,
7139 "Generate one or more insns to set @var{entity} to @var{mode}.\n\
7140 @var{hard_reg_live} is the set of hard registers live at the point where\n\
7141 the insn(s) are to be inserted. @var{prev_moxde} indicates the mode\n\
7142 to switch from, or is the number of modes if the previous mode is not\n\
7143 known. Sets of a lower numbered entity will be emitted before\n\
7144 sets of a higher numbered entity to a mode of the same or lower priority.",
7145 void, (int entity, int mode, int prev_mode, HARD_REG_SET regs_live), NULL)
7147 DEFHOOK
7148 (needed,
7149 "@var{entity} is an integer specifying a mode-switched entity.\n\
7150 If @code{OPTIMIZE_MODE_SWITCHING} is defined, you must define this hook\n\
7151 to return the mode that @var{entity} must be switched into prior to the\n\
7152 execution of @var{insn}, or the number of modes if @var{insn} has no\n\
7153 such requirement. @var{regs_live} contains the set of hard registers\n\
7154 that are live before @var{insn}.",
7155 int, (int entity, rtx_insn *insn, HARD_REG_SET regs_live), NULL)
7157 DEFHOOK
7158 (after,
7159 "@var{entity} is an integer specifying a mode-switched entity.\n\
7160 If this hook is defined, it is evaluated for every @var{insn} during mode\n\
7161 switching. It returns the mode that @var{entity} is in after @var{insn}\n\
7162 has been executed. @var{mode} is the mode that @var{entity} was in\n\
7163 before @var{insn} was executed, taking account of @var{TARGET_MODE_NEEDED}.\n\
7164 @var{regs_live} is the set of hard registers that are live after @var{insn}\n\
7165 has been executed.\n\
7167 @var{mode} is equal to the number of modes defined for @var{entity}\n\
7168 if the mode before @var{insn} is unknown. The hook should likewise return\n\
7169 the number of modes if it does not know what mode @var{entity} has after\n\
7170 @var{insn}.\n\
7172 Not defining the hook is equivalent to returning @var{mode}.",
7173 int, (int entity, int mode, rtx_insn *insn, HARD_REG_SET regs_live), NULL)
7175 DEFHOOK
7176 (confluence,
7177 "By default, the mode-switching pass assumes that a given entity's modes\n\
7178 are mutually exclusive. This means that the pass can only tell\n\
7179 @code{TARGET_MODE_EMIT} about an entity's previous mode if all\n\
7180 incoming paths of execution leave the entity in the same state.\n\
7182 However, some entities might have overlapping, non-exclusive modes,\n\
7183 so that it is sometimes possible to represent ``mode @var{mode1} or mode\n\
7184 @var{mode2}'' with something more specific than ``mode not known''.\n\
7185 If this is true for at least one entity, you should define this hook\n\
7186 and make it return a mode that includes @var{mode1} and @var{mode2}\n\
7187 as possibilities. (The mode can include other possibilities too.)\n\
7188 The hook should return the number of modes if no suitable mode exists\n\
7189 for the given arguments.",
7190 int, (int entity, int mode1, int mode2), NULL)
7192 DEFHOOK
7193 (backprop,
7194 "If defined, the mode-switching pass uses this hook to back-propagate mode\n\
7195 requirements through blocks that have no mode requirements of their own.\n\
7196 Specifically, @var{mode1} is the mode that @var{entity} has on exit\n\
7197 from a block B1 (say) and @var{mode2} is the mode that the next block\n\
7198 requires @var{entity} to have. B1 does not have any mode requirements\n\
7199 of its own.\n\
7201 The hook should return the mode that it prefers or requires @var{entity}\n\
7202 to have in B1, or the number of modes if there is no such requirement.\n\
7203 If the hook returns a required mode for more than one of B1's outgoing\n\
7204 edges, those modes are combined as for @code{TARGET_MODE_CONFLUENCE}.\n\
7206 For example, suppose there is a ``one-shot'' entity that,\n\
7207 for a given execution of a function, either stays off or makes exactly\n\
7208 one transition from off to on. It is safe to make the transition at any\n\
7209 time, but it is better not to do so unnecessarily. This hook allows the\n\
7210 function to manage such an entity without having to track its state at\n\
7211 runtime. Specifically. the entity would have two modes, 0 for off and\n\
7212 1 for on, with 2 representing ``don't know''. The system is forbidden from\n\
7213 transitioning from 2 to 1, since 2 represents the possibility that the\n\
7214 entity is already on (and the aim is to avoid having to emit code to\n\
7215 check for that case). This hook would therefore return 1 when @var{mode1}\n\
7216 is 2 and @var{mode2} is 1, which would force the entity to be on in the\n\
7217 source block. Applying this inductively would remove all transitions\n\
7218 in which the previous state is unknown.",
7219 int, (int entity, int mode1, int mode2), NULL)
7221 DEFHOOK
7222 (entry,
7223 "If this hook is defined, it is evaluated for every @var{entity} that\n\
7224 needs mode switching. It should return the mode that @var{entity} is\n\
7225 guaranteed to be in on entry to the function, or the number of modes\n\
7226 if there is no such guarantee.\n\
7227 If @code{TARGET_MODE_ENTRY} is defined then @code{TARGET_MODE_EXIT}\n\
7228 must be defined.",
7229 int, (int entity), NULL)
7231 DEFHOOK
7232 (exit,
7233 "If this hook is defined, it is evaluated for every @var{entity} that\n\
7234 needs mode switching. It should return the mode that @var{entity} must\n\
7235 be in on return from the function, or the number of modes if there is no\n\
7236 such requirement.\n\
7237 If @code{TARGET_MODE_EXIT} is defined then @code{TARGET_MODE_ENTRY}\n\
7238 must be defined.",
7239 int, (int entity), NULL)
7241 DEFHOOK
7242 (eh_handler,
7243 "If this hook is defined, it should return the mode that @var{entity} is\n\
7244 guaranteed to be in on entry to an exception handler, or the number of modes\n\
7245 if there is no such guarantee.",
7246 int, (int entity), NULL)
7248 DEFHOOK
7249 (priority,
7250 "This hook specifies the order in which modes for @var{entity}\n\
7251 are processed. 0 is the highest priority,\n\
7252 @code{NUM_MODES_FOR_MODE_SWITCHING[@var{entity}] - 1} the lowest.\n\
7253 The hook returns an integer designating a mode\n\
7254 for @var{entity}. For any fixed @var{entity}, @code{mode_priority}\n\
7255 (@var{entity}, @var{n}) shall be a bijection in 0 @dots{}\n\
7256 @code{num_modes_for_mode_switching[@var{entity}] - 1}.",
7257 int, (int entity, int n), NULL)
7259 HOOK_VECTOR_END (mode_switching)
7261 #undef HOOK_PREFIX
7262 #define HOOK_PREFIX "TARGET_MEMTAG_"
7263 HOOK_VECTOR (TARGET_MEMTAG_, memtag)
7265 DEFHOOK
7266 (can_tag_addresses,
7267 "True if the backend architecture naturally supports ignoring some region\n\
7268 of pointers. This feature means that @option{-fsanitize=hwaddress} can\n\
7269 work.\n\
7271 At preset, this feature does not support address spaces. It also requires\n\
7272 @code{Pmode} to be the same as @code{ptr_mode}.",
7273 bool, (), default_memtag_can_tag_addresses)
7275 DEFHOOK
7276 (tag_size,
7277 "Return the size of a tag (in bits) for this platform.\n\
7279 The default returns 8.",
7280 uint8_t, (), default_memtag_tag_size)
7282 DEFHOOK
7283 (granule_size,
7284 "Return the size in real memory that each byte in shadow memory refers to.\n\
7285 I.e. if a variable is @var{X} bytes long in memory, then this hook should\n\
7286 return the value @var{Y} such that the tag in shadow memory spans\n\
7287 @var{X}/@var{Y} bytes.\n\
7289 Most variables will need to be aligned to this amount since two variables\n\
7290 that are neighbors in memory and share a tag granule would need to share\n\
7291 the same tag.\n\
7293 The default returns 16.",
7294 uint8_t, (), default_memtag_granule_size)
7296 DEFHOOK
7297 (insert_random_tag,
7298 "Return an RTX representing the value of @var{untagged} but with a\n\
7299 (possibly) random tag in it.\n\
7300 Put that value into @var{target} if it is convenient to do so.\n\
7301 This function is used to generate a tagged base for the current stack frame.",
7302 rtx, (rtx untagged, rtx target), default_memtag_insert_random_tag)
7304 DEFHOOK
7305 (add_tag,
7306 "Return an RTX that represents the result of adding @var{addr_offset} to\n\
7307 the address in pointer @var{base} and @var{tag_offset} to the tag in pointer\n\
7308 @var{base}.\n\
7309 The resulting RTX must either be a valid memory address or be able to get\n\
7310 put into an operand with @code{force_operand}.\n\
7312 Unlike other memtag hooks, this must return an expression and not emit any\n\
7313 RTL.",
7314 rtx, (rtx base, poly_int64 addr_offset, uint8_t tag_offset),
7315 default_memtag_add_tag)
7317 DEFHOOK
7318 (set_tag,
7319 "Return an RTX representing @var{untagged_base} but with the tag @var{tag}.\n\
7320 Try and store this in @var{target} if convenient.\n\
7321 @var{untagged_base} is required to have a zero tag when this hook is called.\n\
7322 The default of this hook is to set the top byte of @var{untagged_base} to\n\
7323 @var{tag}.",
7324 rtx, (rtx untagged_base, rtx tag, rtx target), default_memtag_set_tag)
7326 DEFHOOK
7327 (extract_tag,
7328 "Return an RTX representing the tag stored in @var{tagged_pointer}.\n\
7329 Store the result in @var{target} if it is convenient.\n\
7330 The default represents the top byte of the original pointer.",
7331 rtx, (rtx tagged_pointer, rtx target), default_memtag_extract_tag)
7333 DEFHOOK
7334 (untagged_pointer,
7335 "Return an RTX representing @var{tagged_pointer} with its tag set to zero.\n\
7336 Store the result in @var{target} if convenient.\n\
7337 The default clears the top byte of the original pointer.",
7338 rtx, (rtx tagged_pointer, rtx target), default_memtag_untagged_pointer)
7340 HOOK_VECTOR_END (memtag)
7341 #undef HOOK_PREFIX
7342 #define HOOK_PREFIX "TARGET_"
7344 #define DEF_TARGET_INSN(NAME, PROTO) \
7345 DEFHOOK_UNDOC (have_##NAME, "", bool, (void), false)
7346 #include "target-insns.def"
7347 #undef DEF_TARGET_INSN
7349 #define DEF_TARGET_INSN(NAME, PROTO) \
7350 DEFHOOK_UNDOC (gen_##NAME, "", rtx_insn *, PROTO, NULL)
7351 #include "target-insns.def"
7352 #undef DEF_TARGET_INSN
7354 #define DEF_TARGET_INSN(NAME, PROTO) \
7355 DEFHOOKPOD (code_for_##NAME, "*", enum insn_code, CODE_FOR_nothing)
7356 #include "target-insns.def"
7357 #undef DEF_TARGET_INSN
7359 DEFHOOK
7360 (run_target_selftests,
7361 "If selftests are enabled, run any selftests for this target.",
7362 void, (void),
7363 NULL)
7365 /* This value represents whether the shadow call stack is implemented on
7366 the target platform. */
7367 DEFHOOKPOD
7368 (have_shadow_call_stack,
7369 "This value is true if the target platform supports\n\
7370 @option{-fsanitize=shadow-call-stack}. The default value is false.",
7371 bool, false)
7373 /* This value represents whether libatomic is available on
7374 the target platform. */
7375 DEFHOOKPOD
7376 (have_libatomic,
7377 "This value is true if the target platform supports\n\
7378 libatomic. The default value is false.",
7379 bool, false)
7381 /* Close the 'struct gcc_target' definition. */
7382 HOOK_VECTOR_END (C90_EMPTY_HACK)