c, c++: attribute format on a ctor with a vbase [PR101833, PR47634]
[official-gcc.git] / gcc / target.def
blobd85adf36a3918ec4ce3409ef05a8d0bdcec9478c
1 /* Target hook definitions.
2 Copyright (C) 2001-2022 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 The hook should return 0 if SIMD clones shouldn't be emitted,\n\
1633 or number of @var{vecsize_mangle} variants that should be emitted.",
1634 int, (struct cgraph_node *, struct cgraph_simd_clone *, tree, int), NULL)
1636 DEFHOOK
1637 (adjust,
1638 "This hook should add implicit @code{attribute(target(\"...\"))} attribute\n\
1639 to SIMD clone @var{node} if needed.",
1640 void, (struct cgraph_node *), NULL)
1642 DEFHOOK
1643 (usable,
1644 "This hook should return -1 if SIMD clone @var{node} shouldn't be used\n\
1645 in vectorized loops in current function, or non-negative number if it is\n\
1646 usable. In that case, the smaller the number is, the more desirable it is\n\
1647 to use it.",
1648 int, (struct cgraph_node *), NULL)
1650 HOOK_VECTOR_END (simd_clone)
1652 /* Functions relating to OpenMP SIMT vectorization transform. */
1653 #undef HOOK_PREFIX
1654 #define HOOK_PREFIX "TARGET_SIMT_"
1655 HOOK_VECTOR (TARGET_SIMT, simt)
1657 DEFHOOK
1658 (vf,
1659 "Return number of threads in SIMT thread group on the target.",
1660 int, (void), NULL)
1662 HOOK_VECTOR_END (simt)
1664 /* Functions relating to OpenMP. */
1665 #undef HOOK_PREFIX
1666 #define HOOK_PREFIX "TARGET_OMP_"
1667 HOOK_VECTOR (TARGET_OMP, omp)
1669 DEFHOOK
1670 (device_kind_arch_isa,
1671 "Return 1 if @var{trait} @var{name} is present in the OpenMP context's\n\
1672 device trait set, return 0 if not present in any OpenMP context in the\n\
1673 whole translation unit, or -1 if not present in the current OpenMP context\n\
1674 but might be present in another OpenMP context in the same TU.",
1675 int, (enum omp_device_kind_arch_isa trait, const char *name), NULL)
1677 HOOK_VECTOR_END (omp)
1679 /* Functions relating to openacc. */
1680 #undef HOOK_PREFIX
1681 #define HOOK_PREFIX "TARGET_GOACC_"
1682 HOOK_VECTOR (TARGET_GOACC, goacc)
1684 DEFHOOK
1685 (validate_dims,
1686 "This hook should check the launch dimensions provided for an OpenACC\n\
1687 compute region, or routine. Defaulted values are represented as -1\n\
1688 and non-constant values as 0. The @var{fn_level} is negative for the\n\
1689 function corresponding to the compute region. For a routine it is the\n\
1690 outermost level at which partitioned execution may be spawned. The hook\n\
1691 should verify non-default values. If DECL is NULL, global defaults\n\
1692 are being validated and unspecified defaults should be filled in.\n\
1693 Diagnostics should be issued as appropriate. Return\n\
1694 true, if changes have been made. You must override this hook to\n\
1695 provide dimensions larger than 1.",
1696 bool, (tree decl, int *dims, int fn_level, unsigned used),
1697 default_goacc_validate_dims)
1699 DEFHOOK
1700 (dim_limit,
1701 "This hook should return the maximum size of a particular dimension,\n\
1702 or zero if unbounded.",
1703 int, (int axis),
1704 default_goacc_dim_limit)
1706 DEFHOOK
1707 (fork_join,
1708 "This hook can be used to convert IFN_GOACC_FORK and IFN_GOACC_JOIN\n\
1709 function calls to target-specific gimple, or indicate whether they\n\
1710 should be retained. It is executed during the oacc_device_lower pass.\n\
1711 It should return true, if the call should be retained. It should\n\
1712 return false, if it is to be deleted (either because target-specific\n\
1713 gimple has been inserted before it, or there is no need for it).\n\
1714 The default hook returns false, if there are no RTL expanders for them.",
1715 bool, (gcall *call, const int *dims, bool is_fork),
1716 default_goacc_fork_join)
1718 DEFHOOK
1719 (reduction,
1720 "This hook is used by the oacc_transform pass to expand calls to the\n\
1721 @var{GOACC_REDUCTION} internal function, into a sequence of gimple\n\
1722 instructions. @var{call} is gimple statement containing the call to\n\
1723 the function. This hook removes statement @var{call} after the\n\
1724 expanded sequence has been inserted. This hook is also responsible\n\
1725 for allocating any storage for reductions when necessary.",
1726 void, (gcall *call),
1727 default_goacc_reduction)
1729 DEFHOOK
1730 (adjust_private_decl,
1731 "This hook, if defined, is used by accelerator target back-ends to adjust\n\
1732 OpenACC variable declarations that should be made private to the given\n\
1733 parallelism level (i.e. @code{GOMP_DIM_GANG}, @code{GOMP_DIM_WORKER} or\n\
1734 @code{GOMP_DIM_VECTOR}). A typical use for this hook is to force variable\n\
1735 declarations at the @code{gang} level to reside in GPU shared memory.\n\
1736 @var{loc} may be used for diagnostic purposes.\n\
1738 You may also use the @code{TARGET_GOACC_EXPAND_VAR_DECL} hook if the\n\
1739 adjusted variable declaration needs to be expanded to RTL in a non-standard\n\
1740 way.",
1741 tree, (location_t loc, tree var, int level),
1742 NULL)
1744 DEFHOOK
1745 (expand_var_decl,
1746 "This hook, if defined, is used by accelerator target back-ends to expand\n\
1747 specially handled kinds of @code{VAR_DECL} expressions. A particular use is\n\
1748 to place variables with specific attributes inside special accelarator\n\
1749 memories. A return value of @code{NULL} indicates that the target does not\n\
1750 handle this @code{VAR_DECL}, and normal RTL expanding is resumed.\n\
1752 Only define this hook if your accelerator target needs to expand certain\n\
1753 @code{VAR_DECL} nodes in a way that differs from the default. You can also adjust\n\
1754 private variables at OpenACC device-lowering time using the\n\
1755 @code{TARGET_GOACC_ADJUST_PRIVATE_DECL} target hook.",
1756 rtx, (tree var),
1757 NULL)
1759 DEFHOOK
1760 (create_worker_broadcast_record,
1761 "Create a record used to propagate local-variable state from an active\n\
1762 worker to other workers. A possible implementation might adjust the type\n\
1763 of REC to place the new variable in shared GPU memory.\n\
1765 Presence of this target hook indicates that middle end neutering/broadcasting\n\
1766 be used.",
1767 tree, (tree rec, bool sender, const char *name, unsigned HOST_WIDE_INT offset),
1768 NULL)
1770 DEFHOOK
1771 (shared_mem_layout,
1772 "Lay out a fixed shared-memory region on the target. The LO and HI\n\
1773 arguments should be set to a range of addresses that can be used for worker\n\
1774 broadcasting. The dimensions, reduction size and gang-private size\n\
1775 arguments are for the current offload region.",
1776 void, (unsigned HOST_WIDE_INT *, unsigned HOST_WIDE_INT *, int[],
1777 unsigned HOST_WIDE_INT[], unsigned HOST_WIDE_INT[]),
1778 NULL)
1780 HOOK_VECTOR_END (goacc)
1782 /* Functions relating to vectorization. */
1783 #undef HOOK_PREFIX
1784 #define HOOK_PREFIX "TARGET_VECTORIZE_"
1785 HOOK_VECTOR (TARGET_VECTORIZE, vectorize)
1787 /* The following member value is a pointer to a function called
1788 by the vectorizer, and return the decl of the target builtin
1789 function. */
1790 DEFHOOK
1791 (builtin_mask_for_load,
1792 "This hook should return the DECL of a function @var{f} that given an\n\
1793 address @var{addr} as an argument returns a mask @var{m} that can be\n\
1794 used to extract from two vectors the relevant data that resides in\n\
1795 @var{addr} in case @var{addr} is not properly aligned.\n\
1797 The autovectorizer, when vectorizing a load operation from an address\n\
1798 @var{addr} that may be unaligned, will generate two vector loads from\n\
1799 the two aligned addresses around @var{addr}. It then generates a\n\
1800 @code{REALIGN_LOAD} operation to extract the relevant data from the\n\
1801 two loaded vectors. The first two arguments to @code{REALIGN_LOAD},\n\
1802 @var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and\n\
1803 the third argument, @var{OFF}, defines how the data will be extracted\n\
1804 from these two vectors: if @var{OFF} is 0, then the returned vector is\n\
1805 @var{v2}; otherwise, the returned vector is composed from the last\n\
1806 @var{VS}-@var{OFF} elements of @var{v1} concatenated to the first\n\
1807 @var{OFF} elements of @var{v2}.\n\
1809 If this hook is defined, the autovectorizer will generate a call\n\
1810 to @var{f} (using the DECL tree that this hook returns) and will\n\
1811 use the return value of @var{f} as the argument @var{OFF} to\n\
1812 @code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}\n\
1813 should comply with the semantics expected by @code{REALIGN_LOAD}\n\
1814 described above.\n\
1815 If this hook is not defined, then @var{addr} will be used as\n\
1816 the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low\n\
1817 log2(@var{VS}) @minus{} 1 bits of @var{addr} will be considered.",
1818 tree, (void), NULL)
1820 /* Returns a built-in function that realizes the vectorized version of
1821 a target-independent function, or NULL_TREE if not available. */
1822 DEFHOOK
1823 (builtin_vectorized_function,
1824 "This hook should return the decl of a function that implements the\n\
1825 vectorized variant of the function with the @code{combined_fn} code\n\
1826 @var{code} or @code{NULL_TREE} if such a function is not available.\n\
1827 The return type of the vectorized function shall be of vector type\n\
1828 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1829 tree, (unsigned code, tree vec_type_out, tree vec_type_in),
1830 default_builtin_vectorized_function)
1832 /* Returns a built-in function that realizes the vectorized version of
1833 a target-specific function, or NULL_TREE if not available. */
1834 DEFHOOK
1835 (builtin_md_vectorized_function,
1836 "This hook should return the decl of a function that implements the\n\
1837 vectorized variant of target built-in function @code{fndecl}. The\n\
1838 return type of the vectorized function shall be of vector type\n\
1839 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1840 tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
1841 default_builtin_md_vectorized_function)
1843 /* Cost of different vector/scalar statements in vectorization cost
1844 model. In case of misaligned vector loads and stores the cost depends
1845 on the data type and misalignment value. */
1846 DEFHOOK
1847 (builtin_vectorization_cost,
1848 "Returns cost of different scalar or vector statements for vectorization cost model.\n\
1849 For vector memory operations the cost may depend on type (@var{vectype}) and\n\
1850 misalignment value (@var{misalign}).",
1851 int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
1852 default_builtin_vectorization_cost)
1854 DEFHOOK
1855 (preferred_vector_alignment,
1856 "This hook returns the preferred alignment in bits for accesses to\n\
1857 vectors of type @var{type} in vectorized code. This might be less than\n\
1858 or greater than the ABI-defined value returned by\n\
1859 @code{TARGET_VECTOR_ALIGNMENT}. It can be equal to the alignment of\n\
1860 a single element, in which case the vectorizer will not try to optimize\n\
1861 for alignment.\n\
1863 The default hook returns @code{TYPE_ALIGN (@var{type})}, which is\n\
1864 correct for most targets.",
1865 poly_uint64, (const_tree type),
1866 default_preferred_vector_alignment)
1868 /* Return true if vector alignment is reachable (by peeling N
1869 iterations) for the given scalar type. */
1870 DEFHOOK
1871 (vector_alignment_reachable,
1872 "Return true if vector alignment is reachable (by peeling N iterations)\n\
1873 for the given scalar type @var{type}. @var{is_packed} is false if the scalar\n\
1874 access using @var{type} is known to be naturally aligned.",
1875 bool, (const_tree type, bool is_packed),
1876 default_builtin_vector_alignment_reachable)
1878 DEFHOOK
1879 (vec_perm_const,
1880 "This hook is used to test whether the target can permute up to two\n\
1881 vectors of mode @var{mode} using the permutation vector @code{sel}, and\n\
1882 also to emit such a permutation. In the former case @var{in0}, @var{in1}\n\
1883 and @var{out} are all null. In the latter case @var{in0} and @var{in1} are\n\
1884 the source vectors and @var{out} is the destination vector; all three are\n\
1885 operands of mode @var{mode}. @var{in1} is the same as @var{in0} if\n\
1886 @var{sel} describes a permutation on one vector instead of two.\n\
1888 Return true if the operation is possible, emitting instructions for it\n\
1889 if rtxes are provided.\n\
1891 @cindex @code{vec_perm@var{m}} instruction pattern\n\
1892 If the hook returns false for a mode with multibyte elements, GCC will\n\
1893 try the equivalent byte operation. If that also fails, it will try forcing\n\
1894 the selector into a register and using the @var{vec_perm@var{mode}}\n\
1895 instruction pattern. There is no need for the hook to handle these two\n\
1896 implementation approaches itself.",
1897 bool, (machine_mode mode, rtx output, rtx in0, rtx in1,
1898 const vec_perm_indices &sel),
1899 NULL)
1901 /* Return true if the target supports misaligned store/load of a
1902 specific factor denoted in the third parameter. The last parameter
1903 is true if the access is defined in a packed struct. */
1904 DEFHOOK
1905 (support_vector_misalignment,
1906 "This hook should return true if the target supports misaligned vector\n\
1907 store/load of a specific factor denoted in the @var{misalignment}\n\
1908 parameter. The vector store/load should be of machine mode @var{mode} and\n\
1909 the elements in the vectors should be of type @var{type}. @var{is_packed}\n\
1910 parameter is true if the memory access is defined in a packed struct.",
1911 bool,
1912 (machine_mode mode, const_tree type, int misalignment, bool is_packed),
1913 default_builtin_support_vector_misalignment)
1915 /* Returns the preferred mode for SIMD operations for the specified
1916 scalar mode. */
1917 DEFHOOK
1918 (preferred_simd_mode,
1919 "This hook should return the preferred mode for vectorizing scalar\n\
1920 mode @var{mode}. The default is\n\
1921 equal to @code{word_mode}, because the vectorizer can do some\n\
1922 transformations even in absence of specialized @acronym{SIMD} hardware.",
1923 machine_mode,
1924 (scalar_mode mode),
1925 default_preferred_simd_mode)
1927 /* Returns the preferred mode for splitting SIMD reductions to. */
1928 DEFHOOK
1929 (split_reduction,
1930 "This hook should return the preferred mode to split the final reduction\n\
1931 step on @var{mode} to. The reduction is then carried out reducing upper\n\
1932 against lower halves of vectors recursively until the specified mode is\n\
1933 reached. The default is @var{mode} which means no splitting.",
1934 machine_mode,
1935 (machine_mode),
1936 default_split_reduction)
1938 /* Returns a mask of vector sizes to iterate over when auto-vectorizing
1939 after processing the preferred one derived from preferred_simd_mode. */
1940 DEFHOOK
1941 (autovectorize_vector_modes,
1942 "If using the mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}\n\
1943 is not the only approach worth considering, this hook should add one mode to\n\
1944 @var{modes} for each useful alternative approach. These modes are then\n\
1945 passed to @code{TARGET_VECTORIZE_RELATED_MODE} to obtain the vector mode\n\
1946 for a given element mode.\n\
1948 The modes returned in @var{modes} should use the smallest element mode\n\
1949 possible for the vectorization approach that they represent, preferring\n\
1950 integer modes over floating-poing modes in the event of a tie. The first\n\
1951 mode should be the @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE} for its\n\
1952 element mode.\n\
1954 If @var{all} is true, add suitable vector modes even when they are generally\n\
1955 not expected to be worthwhile.\n\
1957 The hook returns a bitmask of flags that control how the modes in\n\
1958 @var{modes} are used. The flags are:\n\
1959 @table @code\n\
1960 @item VECT_COMPARE_COSTS\n\
1961 Tells the loop vectorizer to try all the provided modes and pick the one\n\
1962 with the lowest cost. By default the vectorizer will choose the first\n\
1963 mode that works.\n\
1964 @end table\n\
1966 The hook does not need to do anything if the vector returned by\n\
1967 @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE} is the only one relevant\n\
1968 for autovectorization. The default implementation adds no modes and\n\
1969 returns 0.",
1970 unsigned int,
1971 (vector_modes *modes, bool all),
1972 default_autovectorize_vector_modes)
1974 DEFHOOK
1975 (related_mode,
1976 "If a piece of code is using vector mode @var{vector_mode} and also wants\n\
1977 to operate on elements of mode @var{element_mode}, return the vector mode\n\
1978 it should use for those elements. If @var{nunits} is nonzero, ensure that\n\
1979 the mode has exactly @var{nunits} elements, otherwise pick whichever vector\n\
1980 size pairs the most naturally with @var{vector_mode}. Return an empty\n\
1981 @code{opt_machine_mode} if there is no supported vector mode with the\n\
1982 required properties.\n\
1984 There is no prescribed way of handling the case in which @var{nunits}\n\
1985 is zero. One common choice is to pick a vector mode with the same size\n\
1986 as @var{vector_mode}; this is the natural choice if the target has a\n\
1987 fixed vector size. Another option is to choose a vector mode with the\n\
1988 same number of elements as @var{vector_mode}; this is the natural choice\n\
1989 if the target has a fixed number of elements. Alternatively, the hook\n\
1990 might choose a middle ground, such as trying to keep the number of\n\
1991 elements as similar as possible while applying maximum and minimum\n\
1992 vector sizes.\n\
1994 The default implementation uses @code{mode_for_vector} to find the\n\
1995 requested mode, returning a mode with the same size as @var{vector_mode}\n\
1996 when @var{nunits} is zero. This is the correct behavior for most targets.",
1997 opt_machine_mode,
1998 (machine_mode vector_mode, scalar_mode element_mode, poly_uint64 nunits),
1999 default_vectorize_related_mode)
2001 /* Function to get a target mode for a vector mask. */
2002 DEFHOOK
2003 (get_mask_mode,
2004 "Return the mode to use for a vector mask that holds one boolean\n\
2005 result for each element of vector mode @var{mode}. The returned mask mode\n\
2006 can be a vector of integers (class @code{MODE_VECTOR_INT}), a vector of\n\
2007 booleans (class @code{MODE_VECTOR_BOOL}) or a scalar integer (class\n\
2008 @code{MODE_INT}). Return an empty @code{opt_machine_mode} if no such\n\
2009 mask mode exists.\n\
2011 The default implementation returns a @code{MODE_VECTOR_INT} with the\n\
2012 same size and number of elements as @var{mode}, if such a mode exists.",
2013 opt_machine_mode,
2014 (machine_mode mode),
2015 default_get_mask_mode)
2017 /* Function to say whether a masked operation is expensive when the
2018 mask is all zeros. */
2019 DEFHOOK
2020 (empty_mask_is_expensive,
2021 "This hook returns true if masked internal function @var{ifn} (really of\n\
2022 type @code{internal_fn}) should be considered expensive when the mask is\n\
2023 all zeros. GCC can then try to branch around the instruction instead.",
2024 bool,
2025 (unsigned ifn),
2026 default_empty_mask_is_expensive)
2028 /* Target builtin that implements vector gather operation. */
2029 DEFHOOK
2030 (builtin_gather,
2031 "Target builtin that implements vector gather operation. @var{mem_vectype}\n\
2032 is the vector type of the load and @var{index_type} is scalar type of\n\
2033 the index, scaled by @var{scale}.\n\
2034 The default is @code{NULL_TREE} which means to not vectorize gather\n\
2035 loads.",
2036 tree,
2037 (const_tree mem_vectype, const_tree index_type, int scale),
2038 NULL)
2040 /* Target builtin that implements vector scatter operation. */
2041 DEFHOOK
2042 (builtin_scatter,
2043 "Target builtin that implements vector scatter operation. @var{vectype}\n\
2044 is the vector type of the store and @var{index_type} is scalar type of\n\
2045 the index, scaled by @var{scale}.\n\
2046 The default is @code{NULL_TREE} which means to not vectorize scatter\n\
2047 stores.",
2048 tree,
2049 (const_tree vectype, const_tree index_type, int scale),
2050 NULL)
2052 /* Target function to initialize the cost model for a loop or block. */
2053 DEFHOOK
2054 (create_costs,
2055 "This hook should initialize target-specific data structures in preparation\n\
2056 for modeling the costs of vectorizing a loop or basic block. The default\n\
2057 allocates three unsigned integers for accumulating costs for the prologue,\n\
2058 body, and epilogue of the loop or basic block. If @var{loop_info} is\n\
2059 non-NULL, it identifies the loop being vectorized; otherwise a single block\n\
2060 is being vectorized. If @var{costing_for_scalar} is true, it indicates the\n\
2061 current cost model is for the scalar version of a loop or block; otherwise\n\
2062 it is for the vector version.",
2063 class vector_costs *,
2064 (vec_info *vinfo, bool costing_for_scalar),
2065 default_vectorize_create_costs)
2067 HOOK_VECTOR_END (vectorize)
2069 #undef HOOK_PREFIX
2070 #define HOOK_PREFIX "TARGET_"
2072 DEFHOOK
2073 (preferred_else_value,
2074 "This hook returns the target's preferred final argument for a call\n\
2075 to conditional internal function @var{ifn} (really of type\n\
2076 @code{internal_fn}). @var{type} specifies the return type of the\n\
2077 function and @var{ops} are the operands to the conditional operation,\n\
2078 of which there are @var{nops}.\n\
2080 For example, if @var{ifn} is @code{IFN_COND_ADD}, the hook returns\n\
2081 a value of type @var{type} that should be used when @samp{@var{ops}[0]}\n\
2082 and @samp{@var{ops}[1]} are conditionally added together.\n\
2084 This hook is only relevant if the target supports conditional patterns\n\
2085 like @code{cond_add@var{m}}. The default implementation returns a zero\n\
2086 constant of type @var{type}.",
2087 tree,
2088 (unsigned ifn, tree type, unsigned nops, tree *ops),
2089 default_preferred_else_value)
2091 DEFHOOK
2092 (record_offload_symbol,
2093 "Used when offloaded functions are seen in the compilation unit and no named\n\
2094 sections are available. It is called once for each symbol that must be\n\
2095 recorded in the offload function and variable table.",
2096 void, (tree),
2097 hook_void_tree)
2099 DEFHOOKPOD
2100 (absolute_biggest_alignment,
2101 "If defined, this target hook specifies the absolute biggest alignment\n\
2102 that a type or variable can have on this machine, otherwise,\n\
2103 @code{BIGGEST_ALIGNMENT} is used.",
2104 HOST_WIDE_INT, BIGGEST_ALIGNMENT)
2106 /* Allow target specific overriding of option settings after options have
2107 been changed by an attribute or pragma or when it is reset at the
2108 end of the code affected by an attribute or pragma. */
2109 DEFHOOK
2110 (override_options_after_change,
2111 "This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}\n\
2112 but is called when the optimize level is changed via an attribute or\n\
2113 pragma or when it is reset at the end of the code affected by the\n\
2114 attribute or pragma. It is not called at the beginning of compilation\n\
2115 when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these\n\
2116 actions then, you should have @code{TARGET_OPTION_OVERRIDE} call\n\
2117 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.",
2118 void, (void),
2119 hook_void_void)
2121 DEFHOOK
2122 (offload_options,
2123 "Used when writing out the list of options into an LTO file. It should\n\
2124 translate any relevant target-specific options (such as the ABI in use)\n\
2125 into one of the @option{-foffload} options that exist as a common interface\n\
2126 to express such options. It should return a string containing these options,\n\
2127 separated by spaces, which the caller will free.\n",
2128 char *, (void), hook_charptr_void_null)
2130 DEFHOOK_UNDOC
2131 (eh_return_filter_mode,
2132 "Return machine mode for filter value.",
2133 scalar_int_mode, (void),
2134 default_eh_return_filter_mode)
2136 /* Return machine mode for libgcc expanded cmp instructions. */
2137 DEFHOOK
2138 (libgcc_cmp_return_mode,
2139 "This target hook should return the mode to be used for the return value\n\
2140 of compare instructions expanded to libgcc calls. If not defined\n\
2141 @code{word_mode} is returned which is the right choice for a majority of\n\
2142 targets.",
2143 scalar_int_mode, (void),
2144 default_libgcc_cmp_return_mode)
2146 /* Return machine mode for libgcc expanded shift instructions. */
2147 DEFHOOK
2148 (libgcc_shift_count_mode,
2149 "This target hook should return the mode to be used for the shift count operand\n\
2150 of shift instructions expanded to libgcc calls. If not defined\n\
2151 @code{word_mode} is returned which is the right choice for a majority of\n\
2152 targets.",
2153 scalar_int_mode, (void),
2154 default_libgcc_shift_count_mode)
2156 /* Return machine mode to be used for _Unwind_Word type. */
2157 DEFHOOK
2158 (unwind_word_mode,
2159 "Return machine mode to be used for @code{_Unwind_Word} type.\n\
2160 The default is to use @code{word_mode}.",
2161 scalar_int_mode, (void),
2162 default_unwind_word_mode)
2164 /* Given two decls, merge their attributes and return the result. */
2165 DEFHOOK
2166 (merge_decl_attributes,
2167 "Define this target hook if the merging of decl attributes needs special\n\
2168 handling. If defined, the result is a list of the combined\n\
2169 @code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.\n\
2170 @var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of\n\
2171 when this is needed are when one attribute overrides another, or when an\n\
2172 attribute is nullified by a subsequent definition. This function may\n\
2173 call @code{merge_attributes} to handle machine-independent merging.\n\
2175 @findex TARGET_DLLIMPORT_DECL_ATTRIBUTES\n\
2176 If the only target-specific handling you require is @samp{dllimport}\n\
2177 for Microsoft Windows targets, you should define the macro\n\
2178 @code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler\n\
2179 will then define a function called\n\
2180 @code{merge_dllimport_decl_attributes} which can then be defined as\n\
2181 the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also\n\
2182 add @code{handle_dll_attribute} in the attribute table for your port\n\
2183 to perform initial processing of the @samp{dllimport} and\n\
2184 @samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and\n\
2185 @file{i386/i386.cc}, for example.",
2186 tree, (tree olddecl, tree newdecl),
2187 merge_decl_attributes)
2189 /* Given two types, merge their attributes and return the result. */
2190 DEFHOOK
2191 (merge_type_attributes,
2192 "Define this target hook if the merging of type attributes needs special\n\
2193 handling. If defined, the result is a list of the combined\n\
2194 @code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed\n\
2195 that @code{comptypes} has already been called and returned 1. This\n\
2196 function may call @code{merge_attributes} to handle machine-independent\n\
2197 merging.",
2198 tree, (tree type1, tree type2),
2199 merge_type_attributes)
2201 /* Table of machine attributes and functions to handle them.
2202 Ignored if NULL. */
2203 DEFHOOKPOD
2204 (attribute_table,
2205 "If defined, this target hook points to an array of @samp{struct\n\
2206 attribute_spec} (defined in @file{tree-core.h}) specifying the machine\n\
2207 specific attributes for this target and some of the restrictions on the\n\
2208 entities to which these attributes are applied and the arguments they\n\
2209 take.",
2210 const struct attribute_spec *, NULL)
2212 /* Return true iff attribute NAME expects a plain identifier as its first
2213 argument. */
2214 DEFHOOK
2215 (attribute_takes_identifier_p,
2216 "If defined, this target hook is a function which returns true if the\n\
2217 machine-specific attribute named @var{name} expects an identifier\n\
2218 given as its first argument to be passed on as a plain identifier, not\n\
2219 subjected to name lookup. If this is not defined, the default is\n\
2220 false for all machine-specific attributes.",
2221 bool, (const_tree name),
2222 hook_bool_const_tree_false)
2224 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
2225 one if they are compatible and two if they are nearly compatible
2226 (which causes a warning to be generated). */
2227 DEFHOOK
2228 (comp_type_attributes,
2229 "If defined, this target hook is a function which returns zero if the attributes on\n\
2230 @var{type1} and @var{type2} are incompatible, one if they are compatible,\n\
2231 and two if they are nearly compatible (which causes a warning to be\n\
2232 generated). If this is not defined, machine-specific attributes are\n\
2233 supposed always to be compatible.",
2234 int, (const_tree type1, const_tree type2),
2235 hook_int_const_tree_const_tree_1)
2237 /* Assign default attributes to the newly defined TYPE. */
2238 DEFHOOK
2239 (set_default_type_attributes,
2240 "If defined, this target hook is a function which assigns default attributes to\n\
2241 the newly defined @var{type}.",
2242 void, (tree type),
2243 hook_void_tree)
2245 /* Insert attributes on the newly created DECL. */
2246 DEFHOOK
2247 (insert_attributes,
2248 "Define this target hook if you want to be able to add attributes to a decl\n\
2249 when it is being created. This is normally useful for back ends which\n\
2250 wish to implement a pragma by using the attributes which correspond to\n\
2251 the pragma's effect. The @var{node} argument is the decl which is being\n\
2252 created. The @var{attr_ptr} argument is a pointer to the attribute list\n\
2253 for this decl. The list itself should not be modified, since it may be\n\
2254 shared with other decls, but attributes may be chained on the head of\n\
2255 the list and @code{*@var{attr_ptr}} modified to point to the new\n\
2256 attributes, or a copy of the list may be made if further changes are\n\
2257 needed.",
2258 void, (tree node, tree *attr_ptr),
2259 hook_void_tree_treeptr)
2261 /* Perform additional target-specific processing of generic attributes. */
2262 DEFHOOK
2263 (handle_generic_attribute,
2264 "Define this target hook if you want to be able to perform additional\n\
2265 target-specific processing of an attribute which is handled generically\n\
2266 by a front end. The arguments are the same as those which are passed to\n\
2267 attribute handlers. So far this only affects the @var{noinit} and\n\
2268 @var{section} attribute.",
2269 tree, (tree *node, tree name, tree args, int flags, bool *no_add_attrs),
2270 hook_tree_treeptr_tree_tree_int_boolptr_null)
2272 /* Return true if FNDECL (which has at least one machine attribute)
2273 can be inlined despite its machine attributes, false otherwise. */
2274 DEFHOOK
2275 (function_attribute_inlinable_p,
2276 "@cindex inlining\n\
2277 This target hook returns @code{true} if it is OK to inline @var{fndecl}\n\
2278 into the current function, despite its having target-specific\n\
2279 attributes, @code{false} otherwise. By default, if a function has a\n\
2280 target specific attribute attached to it, it will not be inlined.",
2281 bool, (const_tree fndecl),
2282 hook_bool_const_tree_false)
2284 /* Return true if bitfields in RECORD_TYPE should follow the
2285 Microsoft Visual C++ bitfield layout rules. */
2286 DEFHOOK
2287 (ms_bitfield_layout_p,
2288 "This target hook returns @code{true} if bit-fields in the given\n\
2289 @var{record_type} are to be laid out following the rules of Microsoft\n\
2290 Visual C/C++, namely: (i) a bit-field won't share the same storage\n\
2291 unit with the previous bit-field if their underlying types have\n\
2292 different sizes, and the bit-field will be aligned to the highest\n\
2293 alignment of the underlying types of itself and of the previous\n\
2294 bit-field; (ii) a zero-sized bit-field will affect the alignment of\n\
2295 the whole enclosing structure, even if it is unnamed; except that\n\
2296 (iii) a zero-sized bit-field will be disregarded unless it follows\n\
2297 another bit-field of nonzero size. If this hook returns @code{true},\n\
2298 other macros that control bit-field layout are ignored.\n\
2300 When a bit-field is inserted into a packed record, the whole size\n\
2301 of the underlying type is used by one or more same-size adjacent\n\
2302 bit-fields (that is, if its long:3, 32 bits is used in the record,\n\
2303 and any additional adjacent long bit-fields are packed into the same\n\
2304 chunk of 32 bits. However, if the size changes, a new field of that\n\
2305 size is allocated). In an unpacked record, this is the same as using\n\
2306 alignment, but not equivalent when packing.\n\
2308 If both MS bit-fields and @samp{__attribute__((packed))} are used,\n\
2309 the latter will take precedence. If @samp{__attribute__((packed))} is\n\
2310 used on a single field when MS bit-fields are in use, it will take\n\
2311 precedence for that field, but the alignment of the rest of the structure\n\
2312 may affect its placement.",
2313 bool, (const_tree record_type),
2314 hook_bool_const_tree_false)
2316 /* For now this is only an interface to WORDS_BIG_ENDIAN for
2317 target-independent code like the front ends, need performance testing
2318 before switching completely to the target hook. */
2319 DEFHOOK_UNDOC
2320 (words_big_endian,
2322 bool, (void),
2323 targhook_words_big_endian)
2325 /* Likewise for FLOAT_WORDS_BIG_ENDIAN. */
2326 DEFHOOK_UNDOC
2327 (float_words_big_endian,
2329 bool, (void),
2330 targhook_float_words_big_endian)
2332 DEFHOOK
2333 (float_exceptions_rounding_supported_p,
2334 "Returns true if the target supports IEEE 754 floating-point exceptions\n\
2335 and rounding modes, false otherwise. This is intended to relate to the\n\
2336 @code{float} and @code{double} types, but not necessarily @code{long double}.\n\
2337 By default, returns true if the @code{adddf3} instruction pattern is\n\
2338 available and false otherwise, on the assumption that hardware floating\n\
2339 point supports exceptions and rounding modes but software floating point\n\
2340 does not.",
2341 bool, (void),
2342 default_float_exceptions_rounding_supported_p)
2344 /* True if the target supports decimal floating point. */
2345 DEFHOOK
2346 (decimal_float_supported_p,
2347 "Returns true if the target supports decimal floating point.",
2348 bool, (void),
2349 default_decimal_float_supported_p)
2351 /* True if the target supports fixed-point. */
2352 DEFHOOK
2353 (fixed_point_supported_p,
2354 "Returns true if the target supports fixed-point arithmetic.",
2355 bool, (void),
2356 default_fixed_point_supported_p)
2358 /* Return true if anonymous bitfields affect structure alignment. */
2359 DEFHOOK
2360 (align_anon_bitfield,
2361 "When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine\n\
2362 whether unnamed bitfields affect the alignment of the containing\n\
2363 structure. The hook should return true if the structure should inherit\n\
2364 the alignment requirements of an unnamed bitfield's type.",
2365 bool, (void),
2366 hook_bool_void_false)
2368 /* Return true if volatile bitfields should use the narrowest type possible.
2369 Return false if they should use the container type. */
2370 DEFHOOK
2371 (narrow_volatile_bitfield,
2372 "This target hook should return @code{true} if accesses to volatile bitfields\n\
2373 should use the narrowest mode possible. It should return @code{false} if\n\
2374 these accesses should use the bitfield container type.\n\
2376 The default is @code{false}.",
2377 bool, (void),
2378 hook_bool_void_false)
2380 /* Set up target-specific built-in functions. */
2381 DEFHOOK
2382 (init_builtins,
2383 "Define this hook if you have any machine-specific built-in functions\n\
2384 that need to be defined. It should be a function that performs the\n\
2385 necessary setup.\n\
2387 Machine specific built-in functions can be useful to expand special machine\n\
2388 instructions that would otherwise not normally be generated because\n\
2389 they have no equivalent in the source language (for example, SIMD vector\n\
2390 instructions or prefetch instructions).\n\
2392 To create a built-in function, call the function\n\
2393 @code{lang_hooks.builtin_function}\n\
2394 which is defined by the language front end. You can use any type nodes set\n\
2395 up by @code{build_common_tree_nodes};\n\
2396 only language front ends that use those two functions will call\n\
2397 @samp{TARGET_INIT_BUILTINS}.",
2398 void, (void),
2399 hook_void_void)
2401 /* Initialize (if INITIALIZE_P is true) and return the target-specific
2402 built-in function decl for CODE.
2403 Return NULL if that is not possible. Return error_mark_node if CODE
2404 is outside of the range of valid target builtin function codes. */
2405 DEFHOOK
2406 (builtin_decl,
2407 "Define this hook if you have any machine-specific built-in functions\n\
2408 that need to be defined. It should be a function that returns the\n\
2409 builtin function declaration for the builtin function code @var{code}.\n\
2410 If there is no such builtin and it cannot be initialized at this time\n\
2411 if @var{initialize_p} is true the function should return @code{NULL_TREE}.\n\
2412 If @var{code} is out of range the function should return\n\
2413 @code{error_mark_node}.",
2414 tree, (unsigned code, bool initialize_p), NULL)
2416 /* Expand a target-specific builtin. */
2417 DEFHOOK
2418 (expand_builtin,
2419 "\n\
2420 Expand a call to a machine specific built-in function that was set up by\n\
2421 @samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the\n\
2422 function call; the result should go to @var{target} if that is\n\
2423 convenient, and have mode @var{mode} if that is convenient.\n\
2424 @var{subtarget} may be used as the target for computing one of\n\
2425 @var{exp}'s operands. @var{ignore} is nonzero if the value is to be\n\
2426 ignored. This function should return the result of the call to the\n\
2427 built-in function.",
2428 rtx,
2429 (tree exp, rtx target, rtx subtarget, machine_mode mode, int ignore),
2430 default_expand_builtin)
2432 /* Select a replacement for a target-specific builtin. This is done
2433 *before* regular type checking, and so allows the target to
2434 implement a crude form of function overloading. The result is a
2435 complete expression that implements the operation. PARAMS really
2436 has type VEC(tree,gc)*, but we don't want to include tree.h here. */
2437 DEFHOOK
2438 (resolve_overloaded_builtin,
2439 "Select a replacement for a machine specific built-in function that\n\
2440 was set up by @samp{TARGET_INIT_BUILTINS}. This is done\n\
2441 @emph{before} regular type checking, and so allows the target to\n\
2442 implement a crude form of function overloading. @var{fndecl} is the\n\
2443 declaration of the built-in function. @var{arglist} is the list of\n\
2444 arguments passed to the built-in function. The result is a\n\
2445 complete expression that implements the operation, usually\n\
2446 another @code{CALL_EXPR}.\n\
2447 @var{arglist} really has type @samp{VEC(tree,gc)*}",
2448 tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
2450 DEFHOOK
2451 (check_builtin_call,
2452 "Perform semantic checking on a call to a machine-specific built-in\n\
2453 function after its arguments have been constrained to the function\n\
2454 signature. Return true if the call is valid, otherwise report an error\n\
2455 and return false.\n\
2457 This hook is called after @code{TARGET_RESOLVE_OVERLOADED_BUILTIN}.\n\
2458 The call was originally to built-in function @var{orig_fndecl},\n\
2459 but after the optional @code{TARGET_RESOLVE_OVERLOADED_BUILTIN}\n\
2460 step is now to built-in function @var{fndecl}. @var{loc} is the\n\
2461 location of the call and @var{args} is an array of function arguments,\n\
2462 of which there are @var{nargs}. @var{arg_loc} specifies the location\n\
2463 of each argument.",
2464 bool, (location_t loc, vec<location_t> arg_loc, tree fndecl,
2465 tree orig_fndecl, unsigned int nargs, tree *args),
2466 NULL)
2468 /* Fold a target-specific builtin to a tree valid for both GIMPLE
2469 and GENERIC. */
2470 DEFHOOK
2471 (fold_builtin,
2472 "Fold a call to a machine specific built-in function that was set up by\n\
2473 @samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the\n\
2474 built-in function. @var{n_args} is the number of arguments passed to\n\
2475 the function; the arguments themselves are pointed to by @var{argp}.\n\
2476 The result is another tree, valid for both GIMPLE and GENERIC,\n\
2477 containing a simplified expression for the call's result. If\n\
2478 @var{ignore} is true the value will be ignored.",
2479 tree, (tree fndecl, int n_args, tree *argp, bool ignore),
2480 hook_tree_tree_int_treep_bool_null)
2482 /* Fold a target-specific builtin to a valid GIMPLE tree. */
2483 DEFHOOK
2484 (gimple_fold_builtin,
2485 "Fold a call to a machine specific built-in function that was set up\n\
2486 by @samp{TARGET_INIT_BUILTINS}. @var{gsi} points to the gimple\n\
2487 statement holding the function call. Returns true if any change\n\
2488 was made to the GIMPLE stream.",
2489 bool, (gimple_stmt_iterator *gsi),
2490 hook_bool_gsiptr_false)
2492 /* Target hook is used to compare the target attributes in two functions to
2493 determine which function's features get higher priority. This is used
2494 during function multi-versioning to figure out the order in which two
2495 versions must be dispatched. A function version with a higher priority
2496 is checked for dispatching earlier. DECL1 and DECL2 are
2497 the two function decls that will be compared. It returns positive value
2498 if DECL1 is higher priority, negative value if DECL2 is higher priority
2499 and 0 if they are the same. */
2500 DEFHOOK
2501 (compare_version_priority,
2502 "This hook is used to compare the target attributes in two functions to\n\
2503 determine which function's features get higher priority. This is used\n\
2504 during function multi-versioning to figure out the order in which two\n\
2505 versions must be dispatched. A function version with a higher priority\n\
2506 is checked for dispatching earlier. @var{decl1} and @var{decl2} are\n\
2507 the two function decls that will be compared.",
2508 int, (tree decl1, tree decl2), NULL)
2510 /* Target hook is used to generate the dispatcher logic to invoke the right
2511 function version at run-time for a given set of function versions.
2512 ARG points to the callgraph node of the dispatcher function whose body
2513 must be generated. */
2514 DEFHOOK
2515 (generate_version_dispatcher_body,
2516 "This hook is used to generate the dispatcher logic to invoke the right\n\
2517 function version at run-time for a given set of function versions.\n\
2518 @var{arg} points to the callgraph node of the dispatcher function whose\n\
2519 body must be generated.",
2520 tree, (void *arg), NULL)
2522 /* Target hook is used to get the dispatcher function for a set of function
2523 versions. The dispatcher function is called to invoke the right function
2524 version at run-time. DECL is one version from a set of semantically
2525 identical versions. */
2526 DEFHOOK
2527 (get_function_versions_dispatcher,
2528 "This hook is used to get the dispatcher function for a set of function\n\
2529 versions. The dispatcher function is called to invoke the right function\n\
2530 version at run-time. @var{decl} is one version from a set of semantically\n\
2531 identical versions.",
2532 tree, (void *decl), NULL)
2534 /* Returns a code for a target-specific builtin that implements
2535 reciprocal of a target-specific function, or NULL_TREE if not available. */
2536 DEFHOOK
2537 (builtin_reciprocal,
2538 "This hook should return the DECL of a function that implements the\n\
2539 reciprocal of the machine-specific builtin function @var{fndecl}, or\n\
2540 @code{NULL_TREE} if such a function is not available.",
2541 tree, (tree fndecl),
2542 default_builtin_reciprocal)
2544 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
2545 string containing the C++ mangling for TYPE. In all other cases, return
2546 NULL. */
2547 DEFHOOK
2548 (mangle_type,
2549 "If your target defines any fundamental types, or any types your target\n\
2550 uses should be mangled differently from the default, define this hook\n\
2551 to return the appropriate encoding for these types as part of a C++\n\
2552 mangled name. The @var{type} argument is the tree structure representing\n\
2553 the type to be mangled. The hook may be applied to trees which are\n\
2554 not target-specific fundamental types; it should return @code{NULL}\n\
2555 for all such types, as well as arguments it does not recognize. If the\n\
2556 return value is not @code{NULL}, it must point to a statically-allocated\n\
2557 string constant.\n\
2559 Target-specific fundamental types might be new fundamental types or\n\
2560 qualified versions of ordinary fundamental types. Encode new\n\
2561 fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}\n\
2562 is the name used for the type in source code, and @var{n} is the\n\
2563 length of @var{name} in decimal. Encode qualified versions of\n\
2564 ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where\n\
2565 @var{name} is the name used for the type qualifier in source code,\n\
2566 @var{n} is the length of @var{name} as above, and @var{code} is the\n\
2567 code used to represent the unqualified version of this type. (See\n\
2568 @code{write_builtin_type} in @file{cp/mangle.cc} for the list of\n\
2569 codes.) In both cases the spaces are for clarity; do not include any\n\
2570 spaces in your string.\n\
2572 This hook is applied to types prior to typedef resolution. If the mangled\n\
2573 name for a particular type depends only on that type's main variant, you\n\
2574 can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}\n\
2575 before mangling.\n\
2577 The default version of this hook always returns @code{NULL}, which is\n\
2578 appropriate for a target that does not define any new fundamental\n\
2579 types.",
2580 const char *, (const_tree type),
2581 hook_constcharptr_const_tree_null)
2583 /* Make any adjustments to libfunc names needed for this target. */
2584 DEFHOOK
2585 (init_libfuncs,
2586 "This hook should declare additional library routines or rename\n\
2587 existing ones, using the functions @code{set_optab_libfunc} and\n\
2588 @code{init_one_libfunc} defined in @file{optabs.cc}.\n\
2589 @code{init_optabs} calls this macro after initializing all the normal\n\
2590 library routines.\n\
2592 The default is to do nothing. Most ports don't need to define this hook.",
2593 void, (void),
2594 hook_void_void)
2596 /* Add a __gnu_ prefix to library functions rather than just __. */
2597 DEFHOOKPOD
2598 (libfunc_gnu_prefix,
2599 "If false (the default), internal library routines start with two\n\
2600 underscores. If set to true, these routines start with @code{__gnu_}\n\
2601 instead. E.g., @code{__muldi3} changes to @code{__gnu_muldi3}. This\n\
2602 currently only affects functions defined in @file{libgcc2.c}. If this\n\
2603 is set to true, the @file{tm.h} file must also\n\
2604 @code{#define LIBGCC2_GNU_PREFIX}.",
2605 bool, false)
2607 /* Given a decl, a section name, and whether the decl initializer
2608 has relocs, choose attributes for the section. */
2609 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
2610 DEFHOOK
2611 (section_type_flags,
2612 "Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}\n\
2613 based on a variable or function decl, a section name, and whether or not the\n\
2614 declaration's initializer may contain runtime relocations. @var{decl} may be\n\
2615 null, in which case read-write data should be assumed.\n\
2617 The default version of this function handles choosing code vs data,\n\
2618 read-only vs read-write data, and @code{flag_pic}. You should only\n\
2619 need to override this if your target has special flags that might be\n\
2620 set via @code{__attribute__}.",
2621 unsigned int, (tree decl, const char *name, int reloc),
2622 default_section_type_flags)
2624 DEFHOOK
2625 (libc_has_function,
2626 "This hook determines whether a function from a class of functions\n\
2627 @var{fn_class} is present in the target C library. If @var{type} is NULL,\n\
2628 the caller asks for support for all standard (float, double, long double)\n\
2629 types. If @var{type} is non-NULL, the caller asks for support for a\n\
2630 specific type.",
2631 bool, (enum function_class fn_class, tree type),
2632 default_libc_has_function)
2634 DEFHOOK
2635 (libc_has_fast_function,
2636 "This hook determines whether a function from a class of functions\n\
2637 @code{(enum function_class)}@var{fcode} has a fast implementation.",
2638 bool, (int fcode),
2639 default_libc_has_fast_function)
2641 /* True if new jumps cannot be created, to replace existing ones or
2642 not, at the current point in the compilation. */
2643 DEFHOOK
2644 (cannot_modify_jumps_p,
2645 "This target hook returns @code{true} past the point in which new jump\n\
2646 instructions could be created. On machines that require a register for\n\
2647 every jump such as the SHmedia ISA of SH5, this point would typically be\n\
2648 reload, so this target hook should be defined to a function such as:\n\
2650 @smallexample\n\
2651 static bool\n\
2652 cannot_modify_jumps_past_reload_p ()\n\
2653 @{\n\
2654 return (reload_completed || reload_in_progress);\n\
2655 @}\n\
2656 @end smallexample",
2657 bool, (void),
2658 hook_bool_void_false)
2660 /* True if FOLLOWER may be modified to follow FOLLOWEE. */
2661 DEFHOOK
2662 (can_follow_jump,
2663 "FOLLOWER and FOLLOWEE are JUMP_INSN instructions;\n\
2664 return true if FOLLOWER may be modified to follow FOLLOWEE;\n\
2665 false, if it can't.\n\
2666 For example, on some targets, certain kinds of branches can't be made to\n\
2667 follow through a hot/cold partitioning.",
2668 bool, (const rtx_insn *follower, const rtx_insn *followee),
2669 hook_bool_const_rtx_insn_const_rtx_insn_true)
2671 /* Return true if the target supports conditional execution. */
2672 DEFHOOK
2673 (have_conditional_execution,
2674 "This target hook returns true if the target supports conditional execution.\n\
2675 This target hook is required only when the target has several different\n\
2676 modes and they have different conditional execution capability, such as ARM.",
2677 bool, (void),
2678 default_have_conditional_execution)
2680 DEFHOOK
2681 (gen_ccmp_first,
2682 "This function prepares to emit a comparison insn for the first compare in a\n\
2683 sequence of conditional comparisions. It returns an appropriate comparison\n\
2684 with @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2685 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2686 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2687 compares in the conditional comparision are generated without error.\n\
2688 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.",
2689 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, int code, tree op0, tree op1),
2690 NULL)
2692 DEFHOOK
2693 (gen_ccmp_next,
2694 "This function prepares to emit a conditional comparison within a sequence\n\
2695 of conditional comparisons. It returns an appropriate comparison with\n\
2696 @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2697 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2698 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2699 compares in the conditional comparision are generated without error. The\n\
2700 @var{prev} expression is the result of a prior call to @code{gen_ccmp_first}\n\
2701 or @code{gen_ccmp_next}. It may return @code{NULL} if the combination of\n\
2702 @var{prev} and this comparison is not supported, otherwise the result must\n\
2703 be appropriate for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2704 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.\n\
2705 @var{bit_code} is @code{AND} or @code{IOR}, which is the op on the compares.",
2706 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, rtx prev, int cmp_code, tree op0, tree op1, int bit_code),
2707 NULL)
2709 DEFHOOK
2710 (gen_memset_scratch_rtx,
2711 "This hook should return an rtx for a scratch register in @var{mode} to\n\
2712 be used when expanding memset calls. The backend can use a hard scratch\n\
2713 register to avoid stack realignment when expanding memset. The default\n\
2714 is @code{gen_reg_rtx}.",
2715 rtx, (machine_mode mode),
2716 gen_reg_rtx)
2718 /* Return a new value for loop unroll size. */
2719 DEFHOOK
2720 (loop_unroll_adjust,
2721 "This target hook returns a new value for the number of times @var{loop}\n\
2722 should be unrolled. The parameter @var{nunroll} is the number of times\n\
2723 the loop is to be unrolled. The parameter @var{loop} is a pointer to\n\
2724 the loop, which is going to be checked for unrolling. This target hook\n\
2725 is required only when the target has special constraints like maximum\n\
2726 number of memory accesses.",
2727 unsigned, (unsigned nunroll, class loop *loop),
2728 NULL)
2730 /* True if X is a legitimate MODE-mode immediate operand. */
2731 DEFHOOK
2732 (legitimate_constant_p,
2733 "This hook returns true if @var{x} is a legitimate constant for a\n\
2734 @var{mode}-mode immediate operand on the target machine. You can assume that\n\
2735 @var{x} satisfies @code{CONSTANT_P}, so you need not check this.\n\
2737 The default definition returns true.",
2738 bool, (machine_mode mode, rtx x),
2739 hook_bool_mode_rtx_true)
2741 /* True if X is a TLS operand whose value should be pre-computed. */
2742 DEFHOOK
2743 (precompute_tls_p,
2744 "This hook returns true if @var{x} is a TLS operand on the target\n\
2745 machine that should be pre-computed when used as the argument in a call.\n\
2746 You can assume that @var{x} satisfies @code{CONSTANT_P}, so you need not \n\
2747 check this.\n\
2749 The default definition returns false.",
2750 bool, (machine_mode mode, rtx x),
2751 hook_bool_mode_rtx_false)
2753 /* True if the constant X cannot be placed in the constant pool. */
2754 DEFHOOK
2755 (cannot_force_const_mem,
2756 "This hook should return true if @var{x} is of a form that cannot (or\n\
2757 should not) be spilled to the constant pool. @var{mode} is the mode\n\
2758 of @var{x}.\n\
2760 The default version of this hook returns false.\n\
2762 The primary reason to define this hook is to prevent reload from\n\
2763 deciding that a non-legitimate constant would be better reloaded\n\
2764 from the constant pool instead of spilling and reloading a register\n\
2765 holding the constant. This restriction is often true of addresses\n\
2766 of TLS symbols for various targets.",
2767 bool, (machine_mode mode, rtx x),
2768 hook_bool_mode_rtx_false)
2770 DEFHOOK_UNDOC
2771 (cannot_copy_insn_p,
2772 "True if the insn @var{x} cannot be duplicated.",
2773 bool, (rtx_insn *), NULL)
2775 /* True if X is considered to be commutative. */
2776 DEFHOOK
2777 (commutative_p,
2778 "This target hook returns @code{true} if @var{x} is considered to be commutative.\n\
2779 Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider\n\
2780 PLUS to be commutative inside a MEM@. @var{outer_code} is the rtx code\n\
2781 of the enclosing rtl, if known, otherwise it is UNKNOWN.",
2782 bool, (const_rtx x, int outer_code),
2783 hook_bool_const_rtx_commutative_p)
2785 /* True if ADDR is an address-expression whose effect depends
2786 on the mode of the memory reference it is used in. */
2787 DEFHOOK
2788 (mode_dependent_address_p,
2789 "This hook returns @code{true} if memory address @var{addr} in address\n\
2790 space @var{addrspace} can have\n\
2791 different meanings depending on the machine mode of the memory\n\
2792 reference it is used for or if the address is valid for some modes\n\
2793 but not others.\n\
2795 Autoincrement and autodecrement addresses typically have mode-dependent\n\
2796 effects because the amount of the increment or decrement is the size\n\
2797 of the operand being addressed. Some machines have other mode-dependent\n\
2798 addresses. Many RISC machines have no mode-dependent addresses.\n\
2800 You may assume that @var{addr} is a valid address for the machine.\n\
2802 The default version of this hook returns @code{false}.",
2803 bool, (const_rtx addr, addr_space_t addrspace),
2804 default_mode_dependent_address_p)
2806 /* Given an invalid address X for a given machine mode, try machine-specific
2807 ways to make it legitimate. Return X or an invalid address on failure. */
2808 DEFHOOK
2809 (legitimize_address,
2810 "This hook is given an invalid memory address @var{x} for an\n\
2811 operand of mode @var{mode} and should try to return a valid memory\n\
2812 address.\n\
2814 @findex break_out_memory_refs\n\
2815 @var{x} will always be the result of a call to @code{break_out_memory_refs},\n\
2816 and @var{oldx} will be the operand that was given to that function to produce\n\
2817 @var{x}.\n\
2819 The code of the hook should not alter the substructure of\n\
2820 @var{x}. If it transforms @var{x} into a more legitimate form, it\n\
2821 should return the new @var{x}.\n\
2823 It is not necessary for this hook to come up with a legitimate address,\n\
2824 with the exception of native TLS addresses (@pxref{Emulated TLS}).\n\
2825 The compiler has standard ways of doing so in all cases. In fact, if\n\
2826 the target supports only emulated TLS, it\n\
2827 is safe to omit this hook or make it return @var{x} if it cannot find\n\
2828 a valid way to legitimize the address. But often a machine-dependent\n\
2829 strategy can generate better code.",
2830 rtx, (rtx x, rtx oldx, machine_mode mode),
2831 default_legitimize_address)
2833 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
2834 DEFHOOK
2835 (delegitimize_address,
2836 "This hook is used to undo the possibly obfuscating effects of the\n\
2837 @code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target\n\
2838 macros. Some backend implementations of these macros wrap symbol\n\
2839 references inside an @code{UNSPEC} rtx to represent PIC or similar\n\
2840 addressing modes. This target hook allows GCC's optimizers to understand\n\
2841 the semantics of these opaque @code{UNSPEC}s by converting them back\n\
2842 into their original form.",
2843 rtx, (rtx x),
2844 delegitimize_mem_from_attrs)
2846 /* Given an RTX, return true if it is not ok to emit it into debug info
2847 section. */
2848 DEFHOOK
2849 (const_not_ok_for_debug_p,
2850 "This hook should return true if @var{x} should not be emitted into\n\
2851 debug sections.",
2852 bool, (rtx x),
2853 default_const_not_ok_for_debug_p)
2855 /* Given an address RTX, say whether it is valid. */
2856 DEFHOOK
2857 (legitimate_address_p,
2858 "A function that returns whether @var{x} (an RTX) is a legitimate memory\n\
2859 address on the target machine for a memory operand of mode @var{mode}.\n\
2861 Legitimate addresses are defined in two variants: a strict variant and a\n\
2862 non-strict one. The @var{strict} parameter chooses which variant is\n\
2863 desired by the caller.\n\
2865 The strict variant is used in the reload pass. It must be defined so\n\
2866 that any pseudo-register that has not been allocated a hard register is\n\
2867 considered a memory reference. This is because in contexts where some\n\
2868 kind of register is required, a pseudo-register with no hard register\n\
2869 must be rejected. For non-hard registers, the strict variant should look\n\
2870 up the @code{reg_renumber} array; it should then proceed using the hard\n\
2871 register number in the array, or treat the pseudo as a memory reference\n\
2872 if the array holds @code{-1}.\n\
2874 The non-strict variant is used in other passes. It must be defined to\n\
2875 accept all pseudo-registers in every context where some kind of\n\
2876 register is required.\n\
2878 Normally, constant addresses which are the sum of a @code{symbol_ref}\n\
2879 and an integer are stored inside a @code{const} RTX to mark them as\n\
2880 constant. Therefore, there is no need to recognize such sums\n\
2881 specifically as legitimate addresses. Normally you would simply\n\
2882 recognize any @code{const} as legitimate.\n\
2884 Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant\n\
2885 sums that are not marked with @code{const}. It assumes that a naked\n\
2886 @code{plus} indicates indexing. If so, then you @emph{must} reject such\n\
2887 naked constant sums as illegitimate addresses, so that none of them will\n\
2888 be given to @code{PRINT_OPERAND_ADDRESS}.\n\
2890 @cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation\n\
2891 On some machines, whether a symbolic address is legitimate depends on\n\
2892 the section that the address refers to. On these machines, define the\n\
2893 target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information\n\
2894 into the @code{symbol_ref}, and then check for it here. When you see a\n\
2895 @code{const}, you will have to look inside it to find the\n\
2896 @code{symbol_ref} in order to determine the section. @xref{Assembler\n\
2897 Format}.\n\
2899 @cindex @code{GO_IF_LEGITIMATE_ADDRESS}\n\
2900 Some ports are still using a deprecated legacy substitute for\n\
2901 this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro. This macro\n\
2902 has this syntax:\n\
2904 @example\n\
2905 #define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})\n\
2906 @end example\n\
2908 @noindent\n\
2909 and should @code{goto @var{label}} if the address @var{x} is a valid\n\
2910 address on the target machine for a memory operand of mode @var{mode}.\n\
2912 @findex REG_OK_STRICT\n\
2913 Compiler source files that want to use the strict variant of this\n\
2914 macro define the macro @code{REG_OK_STRICT}. You should use an\n\
2915 @code{#ifdef REG_OK_STRICT} conditional to define the strict variant in\n\
2916 that case and the non-strict variant otherwise.\n\
2918 Using the hook is usually simpler because it limits the number of\n\
2919 files that are recompiled when changes are made.",
2920 bool, (machine_mode mode, rtx x, bool strict),
2921 default_legitimate_address_p)
2923 /* True if the given constant can be put into an object_block. */
2924 DEFHOOK
2925 (use_blocks_for_constant_p,
2926 "This hook should return true if pool entries for constant @var{x} can\n\
2927 be placed in an @code{object_block} structure. @var{mode} is the mode\n\
2928 of @var{x}.\n\
2930 The default version returns false for all constants.",
2931 bool, (machine_mode mode, const_rtx x),
2932 hook_bool_mode_const_rtx_false)
2934 /* True if the given decl can be put into an object_block. */
2935 DEFHOOK
2936 (use_blocks_for_decl_p,
2937 "This hook should return true if pool entries for @var{decl} should\n\
2938 be placed in an @code{object_block} structure.\n\
2940 The default version returns true for all decls.",
2941 bool, (const_tree decl),
2942 hook_bool_const_tree_true)
2944 /* The minimum and maximum byte offsets for anchored addresses. */
2945 DEFHOOKPOD
2946 (min_anchor_offset,
2947 "The minimum offset that should be applied to a section anchor.\n\
2948 On most targets, it should be the smallest offset that can be\n\
2949 applied to a base register while still giving a legitimate address\n\
2950 for every mode. The default value is 0.",
2951 HOST_WIDE_INT, 0)
2953 DEFHOOKPOD
2954 (max_anchor_offset,
2955 "Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)\n\
2956 offset that should be applied to section anchors. The default\n\
2957 value is 0.",
2958 HOST_WIDE_INT, 0)
2960 /* True if section anchors can be used to access the given symbol. */
2961 DEFHOOK
2962 (use_anchors_for_symbol_p,
2963 "Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}\n\
2964 @var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and\n\
2965 @samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.\n\
2967 The default version is correct for most targets, but you might need to\n\
2968 intercept this hook to handle things like target-specific attributes\n\
2969 or target-specific sections.",
2970 bool, (const_rtx x),
2971 default_use_anchors_for_symbol_p)
2973 /* True if target supports indirect functions. */
2974 DEFHOOK
2975 (has_ifunc_p,
2976 "It returns true if the target supports GNU indirect functions.\n\
2977 The support includes the assembler, linker and dynamic linker.\n\
2978 The default value of this hook is based on target's libc.",
2979 bool, (void),
2980 default_has_ifunc_p)
2982 /* True if it is OK to reference indirect function resolvers locally. */
2983 DEFHOOK
2984 (ifunc_ref_local_ok,
2985 "Return true if it is OK to reference indirect function resolvers\n\
2986 locally. The default is to return false.",
2987 bool, (void),
2988 hook_bool_void_false)
2990 /* True if it is OK to do sibling call optimization for the specified
2991 call expression EXP. DECL will be the called function, or NULL if
2992 this is an indirect call. */
2993 DEFHOOK
2994 (function_ok_for_sibcall,
2995 "True if it is OK to do sibling call optimization for the specified\n\
2996 call expression @var{exp}. @var{decl} will be the called function,\n\
2997 or @code{NULL} if this is an indirect call.\n\
2999 It is not uncommon for limitations of calling conventions to prevent\n\
3000 tail calls to functions outside the current unit of translation, or\n\
3001 during PIC compilation. The hook is used to enforce these restrictions,\n\
3002 as the @code{sibcall} md pattern cannot fail, or fall over to a\n\
3003 ``normal'' call. The criteria for successful sibling call optimization\n\
3004 may vary greatly between different architectures.",
3005 bool, (tree decl, tree exp),
3006 hook_bool_tree_tree_false)
3008 /* Establish appropriate back-end context for processing the function
3009 FNDECL. The argument might be NULL to indicate processing at top
3010 level, outside of any function scope. */
3011 DEFHOOK
3012 (set_current_function,
3013 "The compiler invokes this hook whenever it changes its current function\n\
3014 context (@code{cfun}). You can define this function if\n\
3015 the back end needs to perform any initialization or reset actions on a\n\
3016 per-function basis. For example, it may be used to implement function\n\
3017 attributes that affect register usage or code generation patterns.\n\
3018 The argument @var{decl} is the declaration for the new function context,\n\
3019 and may be null to indicate that the compiler has left a function context\n\
3020 and is returning to processing at the top level.\n\
3021 The default hook function does nothing.\n\
3023 GCC sets @code{cfun} to a dummy function context during initialization of\n\
3024 some parts of the back end. The hook function is not invoked in this\n\
3025 situation; you need not worry about the hook being invoked recursively,\n\
3026 or when the back end is in a partially-initialized state.\n\
3027 @code{cfun} might be @code{NULL} to indicate processing at top level,\n\
3028 outside of any function scope.",
3029 void, (tree decl), hook_void_tree)
3031 /* True if EXP should be placed in a "small data" section. */
3032 DEFHOOK
3033 (in_small_data_p,
3034 "Returns true if @var{exp} should be placed into a ``small data'' section.\n\
3035 The default version of this hook always returns false.",
3036 bool, (const_tree exp),
3037 hook_bool_const_tree_false)
3039 /* True if EXP names an object for which name resolution must resolve
3040 to the current executable or shared library. */
3041 DEFHOOK
3042 (binds_local_p,
3043 "Returns true if @var{exp} names an object for which name resolution\n\
3044 rules must resolve to the current ``module'' (dynamic shared library\n\
3045 or executable image).\n\
3047 The default version of this hook implements the name resolution rules\n\
3048 for ELF, which has a looser model of global name binding than other\n\
3049 currently supported object file formats.",
3050 bool, (const_tree exp),
3051 default_binds_local_p)
3053 /* Check if profiling code is before or after prologue. */
3054 DEFHOOK
3055 (profile_before_prologue,
3056 "It returns true if target wants profile code emitted before prologue.\n\n\
3057 The default version of this hook use the target macro\n\
3058 @code{PROFILE_BEFORE_PROLOGUE}.",
3059 bool, (void),
3060 default_profile_before_prologue)
3062 /* Return true if a leaf function should stay leaf even with profiling
3063 enabled. */
3064 DEFHOOK
3065 (keep_leaf_when_profiled,
3066 "This target hook returns true if the target wants the leaf flag for\n\
3067 the current function to stay true even if it calls mcount. This might\n\
3068 make sense for targets using the leaf flag only to determine whether a\n\
3069 stack frame needs to be generated or not and for which the call to\n\
3070 mcount is generated before the function prologue.",
3071 bool, (void),
3072 default_keep_leaf_when_profiled)
3074 /* Modify and return the identifier of a DECL's external name,
3075 originally identified by ID, as required by the target,
3076 (eg, append @nn to windows32 stdcall function names).
3077 The default is to return ID without modification. */
3078 DEFHOOK
3079 (mangle_decl_assembler_name,
3080 "Define this hook if you need to postprocess the assembler name generated\n\
3081 by target-independent code. The @var{id} provided to this hook will be\n\
3082 the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,\n\
3083 or the mangled name of the @var{decl} in C++). The return value of the\n\
3084 hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on\n\
3085 your target system. The default implementation of this hook just\n\
3086 returns the @var{id} provided.",
3087 tree, (tree decl, tree id),
3088 default_mangle_decl_assembler_name)
3090 /* Do something target-specific to record properties of the DECL into
3091 the associated SYMBOL_REF. */
3092 DEFHOOK
3093 (encode_section_info,
3094 "Define this hook if references to a symbol or a constant must be\n\
3095 treated differently depending on something about the variable or\n\
3096 function named by the symbol (such as what section it is in).\n\
3098 The hook is executed immediately after rtl has been created for\n\
3099 @var{decl}, which may be a variable or function declaration or\n\
3100 an entry in the constant pool. In either case, @var{rtl} is the\n\
3101 rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}\n\
3102 in this hook; that field may not have been initialized yet.\n\
3104 In the case of a constant, it is safe to assume that the rtl is\n\
3105 a @code{mem} whose address is a @code{symbol_ref}. Most decls\n\
3106 will also have this form, but that is not guaranteed. Global\n\
3107 register variables, for instance, will have a @code{reg} for their\n\
3108 rtl. (Normally the right thing to do with such unusual rtl is\n\
3109 leave it alone.)\n\
3111 The @var{new_decl_p} argument will be true if this is the first time\n\
3112 that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will\n\
3113 be false for subsequent invocations, which will happen for duplicate\n\
3114 declarations. Whether or not anything must be done for the duplicate\n\
3115 declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.\n\
3116 @var{new_decl_p} is always true when the hook is called for a constant.\n\
3118 @cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}\n\
3119 The usual thing for this hook to do is to record flags in the\n\
3120 @code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.\n\
3121 Historically, the name string was modified if it was necessary to\n\
3122 encode more than one bit of information, but this practice is now\n\
3123 discouraged; use @code{SYMBOL_REF_FLAGS}.\n\
3125 The default definition of this hook, @code{default_encode_section_info}\n\
3126 in @file{varasm.cc}, sets a number of commonly-useful bits in\n\
3127 @code{SYMBOL_REF_FLAGS}. Check whether the default does what you need\n\
3128 before overriding it.",
3129 void, (tree decl, rtx rtl, int new_decl_p),
3130 default_encode_section_info)
3132 /* Undo the effects of encode_section_info on the symbol string. */
3133 DEFHOOK
3134 (strip_name_encoding,
3135 "Decode @var{name} and return the real name part, sans\n\
3136 the characters that @code{TARGET_ENCODE_SECTION_INFO}\n\
3137 may have added.",
3138 const char *, (const char *name),
3139 default_strip_name_encoding)
3141 /* If shift optabs for MODE are known to always truncate the shift count,
3142 return the mask that they apply. Return 0 otherwise. */
3143 DEFHOOK
3144 (shift_truncation_mask,
3145 "This function describes how the standard shift patterns for @var{mode}\n\
3146 deal with shifts by negative amounts or by more than the width of the mode.\n\
3147 @xref{shift patterns}.\n\
3149 On many machines, the shift patterns will apply a mask @var{m} to the\n\
3150 shift count, meaning that a fixed-width shift of @var{x} by @var{y} is\n\
3151 equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If\n\
3152 this is true for mode @var{mode}, the function should return @var{m},\n\
3153 otherwise it should return 0. A return value of 0 indicates that no\n\
3154 particular behavior is guaranteed.\n\
3156 Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does\n\
3157 @emph{not} apply to general shift rtxes; it applies only to instructions\n\
3158 that are generated by the named shift patterns.\n\
3160 The default implementation of this function returns\n\
3161 @code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}\n\
3162 and 0 otherwise. This definition is always safe, but if\n\
3163 @code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns\n\
3164 nevertheless truncate the shift count, you may get better code\n\
3165 by overriding it.",
3166 unsigned HOST_WIDE_INT, (machine_mode mode),
3167 default_shift_truncation_mask)
3169 /* Return the number of divisions in the given MODE that should be present,
3170 so that it is profitable to turn the division into a multiplication by
3171 the reciprocal. */
3172 DEFHOOK
3173 (min_divisions_for_recip_mul,
3174 "When @option{-ffast-math} is in effect, GCC tries to optimize\n\
3175 divisions by the same divisor, by turning them into multiplications by\n\
3176 the reciprocal. This target hook specifies the minimum number of divisions\n\
3177 that should be there for GCC to perform the optimization for a variable\n\
3178 of mode @var{mode}. The default implementation returns 3 if the machine\n\
3179 has an instruction for the division, and 2 if it does not.",
3180 unsigned int, (machine_mode mode),
3181 default_min_divisions_for_recip_mul)
3183 DEFHOOK
3184 (truly_noop_truncation,
3185 "This hook returns true if it is safe to ``convert'' a value of\n\
3186 @var{inprec} bits to one of @var{outprec} bits (where @var{outprec} is\n\
3187 smaller than @var{inprec}) by merely operating on it as if it had only\n\
3188 @var{outprec} bits. The default returns true unconditionally, which\n\
3189 is correct for most machines. When @code{TARGET_TRULY_NOOP_TRUNCATION}\n\
3190 returns false, the machine description should provide a @code{trunc}\n\
3191 optab to specify the RTL that performs the required truncation.\n\
3193 If @code{TARGET_MODES_TIEABLE_P} returns false for a pair of modes,\n\
3194 suboptimal code can result if this hook returns true for the corresponding\n\
3195 mode sizes. Making this hook return false in such cases may improve things.",
3196 bool, (poly_uint64 outprec, poly_uint64 inprec),
3197 hook_bool_puint64_puint64_true)
3199 /* If the representation of integral MODE is such that values are
3200 always sign-extended to a wider mode MODE_REP then return
3201 SIGN_EXTEND. Return UNKNOWN otherwise. */
3202 /* Note that the return type ought to be RTX_CODE, but that's not
3203 necessarily defined at this point. */
3204 DEFHOOK
3205 (mode_rep_extended,
3206 "The representation of an integral mode can be such that the values\n\
3207 are always extended to a wider integral mode. Return\n\
3208 @code{SIGN_EXTEND} if values of @var{mode} are represented in\n\
3209 sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}\n\
3210 otherwise. (Currently, none of the targets use zero-extended\n\
3211 representation this way so unlike @code{LOAD_EXTEND_OP},\n\
3212 @code{TARGET_MODE_REP_EXTENDED} is expected to return either\n\
3213 @code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends\n\
3214 @var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next\n\
3215 widest integral mode and currently we take advantage of this fact.)\n\
3217 Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}\n\
3218 value even if the extension is not performed on certain hard registers\n\
3219 as long as for the @code{REGNO_REG_CLASS} of these hard registers\n\
3220 @code{TARGET_CAN_CHANGE_MODE_CLASS} returns false.\n\
3222 Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}\n\
3223 describe two related properties. If you define\n\
3224 @code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want\n\
3225 to define @code{LOAD_EXTEND_OP (mode)} to return the same type of\n\
3226 extension.\n\
3228 In order to enforce the representation of @code{mode},\n\
3229 @code{TARGET_TRULY_NOOP_TRUNCATION} should return false when truncating to\n\
3230 @code{mode}.",
3231 int, (scalar_int_mode mode, scalar_int_mode rep_mode),
3232 default_mode_rep_extended)
3234 DEFHOOK
3235 (setjmp_preserves_nonvolatile_regs_p,
3236 "On some targets, it is assumed that the compiler will spill all pseudos\n\
3237 that are live across a call to @code{setjmp}, while other targets treat\n\
3238 @code{setjmp} calls as normal function calls.\n\
3240 This hook returns false if @code{setjmp} calls do not preserve all\n\
3241 non-volatile registers so that gcc that must spill all pseudos that are\n\
3242 live across @code{setjmp} calls. Define this to return true if the\n\
3243 target does not need to spill all pseudos live across @code{setjmp} calls.\n\
3244 The default implementation conservatively assumes all pseudos must be\n\
3245 spilled across @code{setjmp} calls.",
3246 bool, (void),
3247 hook_bool_void_false)
3249 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
3250 DEFHOOK
3251 (valid_pointer_mode,
3252 "Define this to return nonzero if the port can handle pointers\n\
3253 with machine mode @var{mode}. The default version of this\n\
3254 hook returns true for both @code{ptr_mode} and @code{Pmode}.",
3255 bool, (scalar_int_mode mode),
3256 default_valid_pointer_mode)
3258 /* Disambiguate with errno. */
3259 DEFHOOK
3260 (ref_may_alias_errno,
3261 "Define this to return nonzero if the memory reference @var{ref}\n\
3262 may alias with the system C library errno location. The default\n\
3263 version of this hook assumes the system C library errno location\n\
3264 is either a declaration of type int or accessed by dereferencing\n\
3265 a pointer to int.",
3266 bool, (ao_ref *ref),
3267 default_ref_may_alias_errno)
3269 /* Support for named address spaces. */
3270 #undef HOOK_PREFIX
3271 #define HOOK_PREFIX "TARGET_ADDR_SPACE_"
3272 HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)
3274 /* MODE to use for a pointer into another address space. */
3275 DEFHOOK
3276 (pointer_mode,
3277 "Define this to return the machine mode to use for pointers to\n\
3278 @var{address_space} if the target supports named address spaces.\n\
3279 The default version of this hook returns @code{ptr_mode}.",
3280 scalar_int_mode, (addr_space_t address_space),
3281 default_addr_space_pointer_mode)
3283 /* MODE to use for an address in another address space. */
3284 DEFHOOK
3285 (address_mode,
3286 "Define this to return the machine mode to use for addresses in\n\
3287 @var{address_space} if the target supports named address spaces.\n\
3288 The default version of this hook returns @code{Pmode}.",
3289 scalar_int_mode, (addr_space_t address_space),
3290 default_addr_space_address_mode)
3292 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
3293 in another address space. */
3294 DEFHOOK
3295 (valid_pointer_mode,
3296 "Define this to return nonzero if the port can handle pointers\n\
3297 with machine mode @var{mode} to address space @var{as}. This target\n\
3298 hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,\n\
3299 except that it includes explicit named address space support. The default\n\
3300 version of this hook returns true for the modes returned by either the\n\
3301 @code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}\n\
3302 target hooks for the given address space.",
3303 bool, (scalar_int_mode mode, addr_space_t as),
3304 default_addr_space_valid_pointer_mode)
3306 /* True if an address is a valid memory address to a given named address
3307 space for a given mode. */
3308 DEFHOOK
3309 (legitimate_address_p,
3310 "Define this to return true if @var{exp} is a valid address for mode\n\
3311 @var{mode} in the named address space @var{as}. The @var{strict}\n\
3312 parameter says whether strict addressing is in effect after reload has\n\
3313 finished. This target hook is the same as the\n\
3314 @code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes\n\
3315 explicit named address space support.",
3316 bool, (machine_mode mode, rtx exp, bool strict, addr_space_t as),
3317 default_addr_space_legitimate_address_p)
3319 /* Return an updated address to convert an invalid pointer to a named
3320 address space to a valid one. If NULL_RTX is returned use machine
3321 independent methods to make the address valid. */
3322 DEFHOOK
3323 (legitimize_address,
3324 "Define this to modify an invalid address @var{x} to be a valid address\n\
3325 with mode @var{mode} in the named address space @var{as}. This target\n\
3326 hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,\n\
3327 except that it includes explicit named address space support.",
3328 rtx, (rtx x, rtx oldx, machine_mode mode, addr_space_t as),
3329 default_addr_space_legitimize_address)
3331 /* True if one named address space is a subset of another named address. */
3332 DEFHOOK
3333 (subset_p,
3334 "Define this to return whether the @var{subset} named address space is\n\
3335 contained within the @var{superset} named address space. Pointers to\n\
3336 a named address space that is a subset of another named address space\n\
3337 will be converted automatically without a cast if used together in\n\
3338 arithmetic operations. Pointers to a superset address space can be\n\
3339 converted to pointers to a subset address space via explicit casts.",
3340 bool, (addr_space_t subset, addr_space_t superset),
3341 default_addr_space_subset_p)
3343 /* True if 0 is a valid address in the address space, or false if
3344 0 is a NULL in the address space. */
3345 DEFHOOK
3346 (zero_address_valid,
3347 "Define this to modify the default handling of address 0 for the\n\
3348 address space. Return true if 0 should be considered a valid address.",
3349 bool, (addr_space_t as),
3350 default_addr_space_zero_address_valid)
3352 /* Function to convert an rtl expression from one address space to another. */
3353 DEFHOOK
3354 (convert,
3355 "Define this to convert the pointer expression represented by the RTL\n\
3356 @var{op} with type @var{from_type} that points to a named address\n\
3357 space to a new pointer expression with type @var{to_type} that points\n\
3358 to a different named address space. When this hook it called, it is\n\
3359 guaranteed that one of the two address spaces is a subset of the other,\n\
3360 as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.",
3361 rtx, (rtx op, tree from_type, tree to_type),
3362 default_addr_space_convert)
3364 /* Function to encode an address space into dwarf. */
3365 DEFHOOK
3366 (debug,
3367 "Define this to define how the address space is encoded in dwarf.\n\
3368 The result is the value to be used with @code{DW_AT_address_class}.",
3369 int, (addr_space_t as),
3370 default_addr_space_debug)
3372 /* Function to emit custom diagnostic if an address space is used. */
3373 DEFHOOK
3374 (diagnose_usage,
3375 "Define this hook if the availability of an address space depends on\n\
3376 command line options and some diagnostics should be printed when the\n\
3377 address space is used. This hook is called during parsing and allows\n\
3378 to emit a better diagnostic compared to the case where the address space\n\
3379 was not registered with @code{c_register_addr_space}. @var{as} is\n\
3380 the address space as registered with @code{c_register_addr_space}.\n\
3381 @var{loc} is the location of the address space qualifier token.\n\
3382 The default implementation does nothing.",
3383 void, (addr_space_t as, location_t loc),
3384 default_addr_space_diagnose_usage)
3386 HOOK_VECTOR_END (addr_space)
3388 #undef HOOK_PREFIX
3389 #define HOOK_PREFIX "TARGET_"
3391 DEFHOOK
3392 (lower_local_decl_alignment,
3393 "Define this hook to lower alignment of local, parm or result\n\
3394 decl @samp{(@var{decl})}.",
3395 void, (tree decl),
3396 hook_void_tree)
3398 DEFHOOK
3399 (static_rtx_alignment,
3400 "This hook returns the preferred alignment in bits for a\n\
3401 statically-allocated rtx, such as a constant pool entry. @var{mode}\n\
3402 is the mode of the rtx. The default implementation returns\n\
3403 @samp{GET_MODE_ALIGNMENT (@var{mode})}.",
3404 HOST_WIDE_INT, (machine_mode mode),
3405 default_static_rtx_alignment)
3407 DEFHOOK
3408 (constant_alignment,
3409 "This hook returns the alignment in bits of a constant that is being\n\
3410 placed in memory. @var{constant} is the constant and @var{basic_align}\n\
3411 is the alignment that the object would ordinarily have.\n\
3413 The default definition just returns @var{basic_align}.\n\
3415 The typical use of this hook is to increase alignment for string\n\
3416 constants to be word aligned so that @code{strcpy} calls that copy\n\
3417 constants can be done inline. The function\n\
3418 @code{constant_alignment_word_strings} provides such a definition.",
3419 HOST_WIDE_INT, (const_tree constant, HOST_WIDE_INT basic_align),
3420 default_constant_alignment)
3422 DEFHOOK
3423 (translate_mode_attribute,
3424 "Define this hook if during mode attribute processing, the port should\n\
3425 translate machine_mode @var{mode} to another mode. For example, rs6000's\n\
3426 @code{KFmode}, when it is the same as @code{TFmode}.\n\
3428 The default version of the hook returns that mode that was passed in.",
3429 machine_mode, (machine_mode mode),
3430 default_translate_mode_attribute)
3432 /* True if MODE is valid for the target. By "valid", we mean able to
3433 be manipulated in non-trivial ways. In particular, this means all
3434 the arithmetic is supported. */
3435 DEFHOOK
3436 (scalar_mode_supported_p,
3437 "Define this to return nonzero if the port is prepared to handle\n\
3438 insns involving scalar mode @var{mode}. For a scalar mode to be\n\
3439 considered supported, all the basic arithmetic and comparisons\n\
3440 must work.\n\
3442 The default version of this hook returns true for any mode\n\
3443 required to handle the basic C types (as defined by the port).\n\
3444 Included here are the double-word arithmetic supported by the\n\
3445 code in @file{optabs.cc}.",
3446 bool, (scalar_mode mode),
3447 default_scalar_mode_supported_p)
3449 /* Similarly for vector modes. "Supported" here is less strict. At
3450 least some operations are supported; need to check optabs or builtins
3451 for further details. */
3452 DEFHOOK
3453 (vector_mode_supported_p,
3454 "Define this to return nonzero if the port is prepared to handle\n\
3455 insns involving vector mode @var{mode}. At the very least, it\n\
3456 must have move patterns for this mode.",
3457 bool, (machine_mode mode),
3458 hook_bool_mode_false)
3460 DEFHOOK
3461 (compatible_vector_types_p,
3462 "Return true if there is no target-specific reason for treating\n\
3463 vector types @var{type1} and @var{type2} as distinct types. The caller\n\
3464 has already checked for target-independent reasons, meaning that the\n\
3465 types are known to have the same mode, to have the same number of elements,\n\
3466 and to have what the caller considers to be compatible element types.\n\
3468 The main reason for defining this hook is to reject pairs of types\n\
3469 that are handled differently by the target's calling convention.\n\
3470 For example, when a new @var{N}-bit vector architecture is added\n\
3471 to a target, the target may want to handle normal @var{N}-bit\n\
3472 @code{VECTOR_TYPE} arguments and return values in the same way as\n\
3473 before, to maintain backwards compatibility. However, it may also\n\
3474 provide new, architecture-specific @code{VECTOR_TYPE}s that are passed\n\
3475 and returned in a more efficient way. It is then important to maintain\n\
3476 a distinction between the ``normal'' @code{VECTOR_TYPE}s and the new\n\
3477 architecture-specific ones.\n\
3479 The default implementation returns true, which is correct for most targets.",
3480 bool, (const_tree type1, const_tree type2),
3481 hook_bool_const_tree_const_tree_true)
3483 DEFHOOK
3484 (vector_alignment,
3485 "This hook can be used to define the alignment for a vector of type\n\
3486 @var{type}, in order to comply with a platform ABI. The default is to\n\
3487 require natural alignment for vector types. The alignment returned by\n\
3488 this hook must be a power-of-two multiple of the default alignment of\n\
3489 the vector element type.",
3490 HOST_WIDE_INT, (const_tree type),
3491 default_vector_alignment)
3493 DEFHOOK
3494 (array_mode,
3495 "Return the mode that GCC should use for an array that has\n\
3496 @var{nelems} elements, with each element having mode @var{mode}.\n\
3497 Return no mode if the target has no special requirements. In the\n\
3498 latter case, GCC looks for an integer mode of the appropriate size\n\
3499 if available and uses BLKmode otherwise. Usually the search for the\n\
3500 integer mode is limited to @code{MAX_FIXED_MODE_SIZE}, but the\n\
3501 @code{TARGET_ARRAY_MODE_SUPPORTED_P} hook allows a larger mode to be\n\
3502 used in specific cases.\n\
3504 The main use of this hook is to specify that an array of vectors should\n\
3505 also have a vector mode. The default implementation returns no mode.",
3506 opt_machine_mode, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3507 hook_optmode_mode_uhwi_none)
3509 /* True if we should try to use a scalar mode to represent an array,
3510 overriding the usual MAX_FIXED_MODE limit. */
3511 DEFHOOK
3512 (array_mode_supported_p,
3513 "Return true if GCC should try to use a scalar mode to store an array\n\
3514 of @var{nelems} elements, given that each element has mode @var{mode}.\n\
3515 Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
3516 and allows GCC to use any defined integer mode.\n\
3518 One use of this hook is to support vector load and store operations\n\
3519 that operate on several homogeneous vectors. For example, ARM NEON\n\
3520 has operations like:\n\
3522 @smallexample\n\
3523 int8x8x3_t vld3_s8 (const int8_t *)\n\
3524 @end smallexample\n\
3526 where the return type is defined as:\n\
3528 @smallexample\n\
3529 typedef struct int8x8x3_t\n\
3530 @{\n\
3531 int8x8_t val[3];\n\
3532 @} int8x8x3_t;\n\
3533 @end smallexample\n\
3535 If this hook allows @code{val} to have a scalar mode, then\n\
3536 @code{int8x8x3_t} can have the same mode. GCC can then store\n\
3537 @code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
3538 bool, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3539 hook_bool_mode_uhwi_false)
3541 DEFHOOK
3542 (libgcc_floating_mode_supported_p,
3543 "Define this to return nonzero if libgcc provides support for the \n\
3544 floating-point mode @var{mode}, which is known to pass \n\
3545 @code{TARGET_SCALAR_MODE_SUPPORTED_P}. The default version of this \n\
3546 hook returns true for all of @code{SFmode}, @code{DFmode}, \n\
3547 @code{XFmode} and @code{TFmode}, if such modes exist.",
3548 bool, (scalar_float_mode mode),
3549 default_libgcc_floating_mode_supported_p)
3551 DEFHOOK
3552 (floatn_mode,
3553 "Define this to return the machine mode to use for the type \n\
3554 @code{_Float@var{n}}, if @var{extended} is false, or the type \n\
3555 @code{_Float@var{n}x}, if @var{extended} is true. If such a type is not\n\
3556 supported, return @code{opt_scalar_float_mode ()}. The default version of\n\
3557 this hook returns @code{SFmode} for @code{_Float32}, @code{DFmode} for\n\
3558 @code{_Float64} and @code{_Float32x} and @code{TFmode} for \n\
3559 @code{_Float128}, if those modes exist and satisfy the requirements for \n\
3560 those types and pass @code{TARGET_SCALAR_MODE_SUPPORTED_P} and \n\
3561 @code{TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P}; for @code{_Float64x}, it \n\
3562 returns the first of @code{XFmode} and @code{TFmode} that exists and \n\
3563 satisfies the same requirements; for other types, it returns \n\
3564 @code{opt_scalar_float_mode ()}. The hook is only called for values\n\
3565 of @var{n} and @var{extended} that are valid according to\n\
3566 ISO/IEC TS 18661-3:2015; that is, @var{n} is one of 32, 64, 128, or,\n\
3567 if @var{extended} is false, 16 or greater than 128 and a multiple of 32.",
3568 opt_scalar_float_mode, (int n, bool extended),
3569 default_floatn_mode)
3571 DEFHOOK
3572 (floatn_builtin_p,
3573 "Define this to return true if the @code{_Float@var{n}} and\n\
3574 @code{_Float@var{n}x} built-in functions should implicitly enable the\n\
3575 built-in function without the @code{__builtin_} prefix in addition to the\n\
3576 normal built-in function with the @code{__builtin_} prefix. The default is\n\
3577 to only enable built-in functions without the @code{__builtin_} prefix for\n\
3578 the GNU C langauge. In strict ANSI/ISO mode, the built-in function without\n\
3579 the @code{__builtin_} prefix is not enabled. The argument @code{FUNC} is the\n\
3580 @code{enum built_in_function} id of the function to be enabled.",
3581 bool, (int func),
3582 default_floatn_builtin_p)
3584 /* Compute cost of moving data from a register of class FROM to one of
3585 TO, using MODE. */
3586 DEFHOOK
3587 (register_move_cost,
3588 "This target hook should return the cost of moving data of mode @var{mode}\n\
3589 from a register in class @var{from} to one in class @var{to}. The classes\n\
3590 are expressed using the enumeration values such as @code{GENERAL_REGS}.\n\
3591 A value of 2 is the default; other values are interpreted relative to\n\
3592 that.\n\
3594 It is not required that the cost always equal 2 when @var{from} is the\n\
3595 same as @var{to}; on some machines it is expensive to move between\n\
3596 registers if they are not general registers.\n\
3598 If reload sees an insn consisting of a single @code{set} between two\n\
3599 hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their\n\
3600 classes returns a value of 2, reload does not check to ensure that the\n\
3601 constraints of the insn are met. Setting a cost of other than 2 will\n\
3602 allow reload to verify that the constraints are met. You should do this\n\
3603 if the @samp{mov@var{m}} pattern's constraints do not allow such copying.\n\
3605 The default version of this function returns 2.",
3606 int, (machine_mode mode, reg_class_t from, reg_class_t to),
3607 default_register_move_cost)
3609 /* Compute cost of moving registers to/from memory. */
3610 /* ??? Documenting the argument types for this hook requires a GFDL
3611 license grant. Also, the documentation uses a different name for RCLASS. */
3612 DEFHOOK
3613 (memory_move_cost,
3614 "This target hook should return the cost of moving data of mode @var{mode}\n\
3615 between a register of class @var{rclass} and memory; @var{in} is @code{false}\n\
3616 if the value is to be written to memory, @code{true} if it is to be read in.\n\
3617 This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.\n\
3618 If moving between registers and memory is more expensive than between two\n\
3619 registers, you should add this target hook to express the relative cost.\n\
3621 If you do not add this target hook, GCC uses a default cost of 4 plus\n\
3622 the cost of copying via a secondary reload register, if one is\n\
3623 needed. If your machine requires a secondary reload register to copy\n\
3624 between memory and a register of @var{rclass} but the reload mechanism is\n\
3625 more complex than copying via an intermediate, use this target hook to\n\
3626 reflect the actual cost of the move.\n\
3628 GCC defines the function @code{memory_move_secondary_cost} if\n\
3629 secondary reloads are needed. It computes the costs due to copying via\n\
3630 a secondary register. If your machine copies from memory using a\n\
3631 secondary register in the conventional way but the default base value of\n\
3632 4 is not correct for your machine, use this target hook to add some other\n\
3633 value to the result of that function. The arguments to that function\n\
3634 are the same as to this target hook.",
3635 int, (machine_mode mode, reg_class_t rclass, bool in),
3636 default_memory_move_cost)
3638 DEFHOOK
3639 (use_by_pieces_infrastructure_p,
3640 "GCC will attempt several strategies when asked to copy between\n\
3641 two areas of memory, or to set, clear or store to memory, for example\n\
3642 when copying a @code{struct}. The @code{by_pieces} infrastructure\n\
3643 implements such memory operations as a sequence of load, store or move\n\
3644 insns. Alternate strategies are to expand the\n\
3645 @code{cpymem} or @code{setmem} optabs, to emit a library call, or to emit\n\
3646 unit-by-unit, loop-based operations.\n\
3648 This target hook should return true if, for a memory operation with a\n\
3649 given @var{size} and @var{alignment}, using the @code{by_pieces}\n\
3650 infrastructure is expected to result in better code generation.\n\
3651 Both @var{size} and @var{alignment} are measured in terms of storage\n\
3652 units.\n\
3654 The parameter @var{op} is one of: @code{CLEAR_BY_PIECES},\n\
3655 @code{MOVE_BY_PIECES}, @code{SET_BY_PIECES}, @code{STORE_BY_PIECES} or\n\
3656 @code{COMPARE_BY_PIECES}. These describe the type of memory operation\n\
3657 under consideration.\n\
3659 The parameter @var{speed_p} is true if the code is currently being\n\
3660 optimized for speed rather than size.\n\
3662 Returning true for higher values of @var{size} can improve code generation\n\
3663 for speed if the target does not provide an implementation of the\n\
3664 @code{cpymem} or @code{setmem} standard names, if the @code{cpymem} or\n\
3665 @code{setmem} implementation would be more expensive than a sequence of\n\
3666 insns, or if the overhead of a library call would dominate that of\n\
3667 the body of the memory operation.\n\
3669 Returning true for higher values of @code{size} may also cause an increase\n\
3670 in code size, for example where the number of insns emitted to perform a\n\
3671 move would be greater than that of a library call.",
3672 bool, (unsigned HOST_WIDE_INT size, unsigned int alignment,
3673 enum by_pieces_operation op, bool speed_p),
3674 default_use_by_pieces_infrastructure_p)
3676 DEFHOOK
3677 (overlap_op_by_pieces_p,
3678 "This target hook should return true if when the @code{by_pieces}\n\
3679 infrastructure is used, an offset adjusted unaligned memory operation\n\
3680 in the smallest integer mode for the last piece operation of a memory\n\
3681 region can be generated to avoid doing more than one smaller operations.",
3682 bool, (void),
3683 hook_bool_void_false)
3685 DEFHOOK
3686 (compare_by_pieces_branch_ratio,
3687 "When expanding a block comparison in MODE, gcc can try to reduce the\n\
3688 number of branches at the expense of more memory operations. This hook\n\
3689 allows the target to override the default choice. It should return the\n\
3690 factor by which branches should be reduced over the plain expansion with\n\
3691 one comparison per @var{mode}-sized piece. A port can also prevent a\n\
3692 particular mode from being used for block comparisons by returning a\n\
3693 negative number from this hook.",
3694 int, (machine_mode mode),
3695 default_compare_by_pieces_branch_ratio)
3697 DEFHOOK
3698 (slow_unaligned_access,
3699 "This hook returns true if memory accesses described by the\n\
3700 @var{mode} and @var{alignment} parameters have a cost many times greater\n\
3701 than aligned accesses, for example if they are emulated in a trap handler.\n\
3702 This hook is invoked only for unaligned accesses, i.e.@: when\n\
3703 @code{@var{alignment} < GET_MODE_ALIGNMENT (@var{mode})}.\n\
3705 When this hook returns true, the compiler will act as if\n\
3706 @code{STRICT_ALIGNMENT} were true when generating code for block\n\
3707 moves. This can cause significantly more instructions to be produced.\n\
3708 Therefore, do not make this hook return true if unaligned accesses only\n\
3709 add a cycle or two to the time for a memory access.\n\
3711 The hook must return true whenever @code{STRICT_ALIGNMENT} is true.\n\
3712 The default implementation returns @code{STRICT_ALIGNMENT}.",
3713 bool, (machine_mode mode, unsigned int align),
3714 default_slow_unaligned_access)
3716 DEFHOOK
3717 (optab_supported_p,
3718 "Return true if the optimizers should use optab @var{op} with\n\
3719 modes @var{mode1} and @var{mode2} for optimization type @var{opt_type}.\n\
3720 The optab is known to have an associated @file{.md} instruction\n\
3721 whose C condition is true. @var{mode2} is only meaningful for conversion\n\
3722 optabs; for direct optabs it is a copy of @var{mode1}.\n\
3724 For example, when called with @var{op} equal to @code{rint_optab} and\n\
3725 @var{mode1} equal to @code{DFmode}, the hook should say whether the\n\
3726 optimizers should use optab @code{rintdf2}.\n\
3728 The default hook returns true for all inputs.",
3729 bool, (int op, machine_mode mode1, machine_mode mode2,
3730 optimization_type opt_type),
3731 default_optab_supported_p)
3733 /* True for MODE if the target expects that registers in this mode will
3734 be allocated to registers in a small register class. The compiler is
3735 allowed to use registers explicitly used in the rtl as spill registers
3736 but it should prevent extending the lifetime of these registers. */
3737 DEFHOOK
3738 (small_register_classes_for_mode_p,
3739 "Define this to return nonzero for machine modes for which the port has\n\
3740 small register classes. If this target hook returns nonzero for a given\n\
3741 @var{mode}, the compiler will try to minimize the lifetime of registers\n\
3742 in @var{mode}. The hook may be called with @code{VOIDmode} as argument.\n\
3743 In this case, the hook is expected to return nonzero if it returns nonzero\n\
3744 for any mode.\n\
3746 On some machines, it is risky to let hard registers live across arbitrary\n\
3747 insns. Typically, these machines have instructions that require values\n\
3748 to be in specific registers (like an accumulator), and reload will fail\n\
3749 if the required hard register is used for another purpose across such an\n\
3750 insn.\n\
3752 Passes before reload do not know which hard registers will be used\n\
3753 in an instruction, but the machine modes of the registers set or used in\n\
3754 the instruction are already known. And for some machines, register\n\
3755 classes are small for, say, integer registers but not for floating point\n\
3756 registers. For example, the AMD x86-64 architecture requires specific\n\
3757 registers for the legacy x86 integer instructions, but there are many\n\
3758 SSE registers for floating point operations. On such targets, a good\n\
3759 strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}\n\
3760 machine modes but zero for the SSE register classes.\n\
3762 The default version of this hook returns false for any mode. It is always\n\
3763 safe to redefine this hook to return with a nonzero value. But if you\n\
3764 unnecessarily define it, you will reduce the amount of optimizations\n\
3765 that can be performed in some cases. If you do not define this hook\n\
3766 to return a nonzero value when it is required, the compiler will run out\n\
3767 of spill registers and print a fatal error message.",
3768 bool, (machine_mode mode),
3769 hook_bool_mode_false)
3771 /* Register number for a flags register. Only needs to be defined if the
3772 target is constrainted to use post-reload comparison elimination. */
3773 DEFHOOKPOD
3774 (flags_regnum,
3775 "If the target has a dedicated flags register, and it needs to use the\n\
3776 post-reload comparison elimination pass, or the delay slot filler pass,\n\
3777 then this value should be set appropriately.",
3778 unsigned int, INVALID_REGNUM)
3780 /* Compute a (partial) cost for rtx X. Return true if the complete
3781 cost has been computed, and false if subexpressions should be
3782 scanned. In either case, *TOTAL contains the cost result. */
3783 /* Note that OUTER_CODE ought to be RTX_CODE, but that's
3784 not necessarily defined at this point. */
3785 DEFHOOK
3786 (rtx_costs,
3787 "This target hook describes the relative costs of RTL expressions.\n\
3789 The cost may depend on the precise form of the expression, which is\n\
3790 available for examination in @var{x}, and the fact that @var{x} appears\n\
3791 as operand @var{opno} of an expression with rtx code @var{outer_code}.\n\
3792 That is, the hook can assume that there is some rtx @var{y} such\n\
3793 that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that\n\
3794 either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or\n\
3795 (b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.\n\
3797 @var{mode} is @var{x}'s machine mode, or for cases like @code{const_int} that\n\
3798 do not have a mode, the mode in which @var{x} is used.\n\
3800 In implementing this hook, you can use the construct\n\
3801 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3802 instructions.\n\
3804 On entry to the hook, @code{*@var{total}} contains a default estimate\n\
3805 for the cost of the expression. The hook should modify this value as\n\
3806 necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}\n\
3807 for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus\n\
3808 operations, and @code{COSTS_N_INSNS (1)} for all other operations.\n\
3810 When optimizing for code size, i.e.@: when @code{speed} is\n\
3811 false, this target hook should be used to estimate the relative\n\
3812 size cost of an expression, again relative to @code{COSTS_N_INSNS}.\n\
3814 The hook returns true when all subexpressions of @var{x} have been\n\
3815 processed, and false when @code{rtx_cost} should recurse.",
3816 bool, (rtx x, machine_mode mode, int outer_code, int opno, int *total, bool speed),
3817 hook_bool_rtx_mode_int_int_intp_bool_false)
3819 /* Compute the cost of X, used as an address. Never called with
3820 invalid addresses. */
3821 DEFHOOK
3822 (address_cost,
3823 "This hook computes the cost of an addressing mode that contains\n\
3824 @var{address}. If not defined, the cost is computed from\n\
3825 the @var{address} expression and the @code{TARGET_RTX_COST} hook.\n\
3827 For most CISC machines, the default cost is a good approximation of the\n\
3828 true cost of the addressing mode. However, on RISC machines, all\n\
3829 instructions normally have the same length and execution time. Hence\n\
3830 all addresses will have equal costs.\n\
3832 In cases where more than one form of an address is known, the form with\n\
3833 the lowest cost will be used. If multiple forms have the same, lowest,\n\
3834 cost, the one that is the most complex will be used.\n\
3836 For example, suppose an address that is equal to the sum of a register\n\
3837 and a constant is used twice in the same basic block. When this macro\n\
3838 is not defined, the address will be computed in a register and memory\n\
3839 references will be indirect through that register. On machines where\n\
3840 the cost of the addressing mode containing the sum is no higher than\n\
3841 that of a simple indirect reference, this will produce an additional\n\
3842 instruction and possibly require an additional register. Proper\n\
3843 specification of this macro eliminates this overhead for such machines.\n\
3845 This hook is never called with an invalid address.\n\
3847 On machines where an address involving more than one register is as\n\
3848 cheap as an address computation involving only one register, defining\n\
3849 @code{TARGET_ADDRESS_COST} to reflect this can cause two registers to\n\
3850 be live over a region of code where only one would have been if\n\
3851 @code{TARGET_ADDRESS_COST} were not defined in that manner. This effect\n\
3852 should be considered in the definition of this macro. Equivalent costs\n\
3853 should probably only be given to addresses with different numbers of\n\
3854 registers on machines with lots of registers.",
3855 int, (rtx address, machine_mode mode, addr_space_t as, bool speed),
3856 default_address_cost)
3858 /* Compute a cost for INSN. */
3859 DEFHOOK
3860 (insn_cost,
3861 "This target hook describes the relative costs of RTL instructions.\n\
3863 In implementing this hook, you can use the construct\n\
3864 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3865 instructions.\n\
3867 When optimizing for code size, i.e.@: when @code{speed} is\n\
3868 false, this target hook should be used to estimate the relative\n\
3869 size cost of an expression, again relative to @code{COSTS_N_INSNS}.",
3870 int, (rtx_insn *insn, bool speed), NULL)
3872 /* Give a cost, in RTX Costs units, for an edge. Like BRANCH_COST, but with
3873 well defined units. */
3874 DEFHOOK
3875 (max_noce_ifcvt_seq_cost,
3876 "This hook returns a value in the same units as @code{TARGET_RTX_COSTS},\n\
3877 giving the maximum acceptable cost for a sequence generated by the RTL\n\
3878 if-conversion pass when conditional execution is not available.\n\
3879 The RTL if-conversion pass attempts to convert conditional operations\n\
3880 that would require a branch to a series of unconditional operations and\n\
3881 @code{mov@var{mode}cc} insns. This hook returns the maximum cost of the\n\
3882 unconditional instructions and the @code{mov@var{mode}cc} insns.\n\
3883 RTL if-conversion is cancelled if the cost of the converted sequence\n\
3884 is greater than the value returned by this hook.\n\
3886 @code{e} is the edge between the basic block containing the conditional\n\
3887 branch to the basic block which would be executed if the condition\n\
3888 were true.\n\
3890 The default implementation of this hook uses the\n\
3891 @code{max-rtl-if-conversion-[un]predictable} parameters if they are set,\n\
3892 and uses a multiple of @code{BRANCH_COST} otherwise.",
3893 unsigned int, (edge e),
3894 default_max_noce_ifcvt_seq_cost)
3896 /* Return true if the given instruction sequence is a good candidate
3897 as a replacement for the if-convertible sequence. */
3898 DEFHOOK
3899 (noce_conversion_profitable_p,
3900 "This hook returns true if the instruction sequence @code{seq} is a good\n\
3901 candidate as a replacement for the if-convertible sequence described in\n\
3902 @code{if_info}.",
3903 bool, (rtx_insn *seq, struct noce_if_info *if_info),
3904 default_noce_conversion_profitable_p)
3906 /* Return true if new_addr should be preferred over the existing address used by
3907 memref in insn. */
3908 DEFHOOK
3909 (new_address_profitable_p,
3910 "Return @code{true} if it is profitable to replace the address in\n\
3911 @var{memref} with @var{new_addr}. This allows targets to prevent the\n\
3912 scheduler from undoing address optimizations. The instruction containing the\n\
3913 memref is @var{insn}. The default implementation returns @code{true}.",
3914 bool, (rtx memref, rtx_insn * insn, rtx new_addr),
3915 default_new_address_profitable_p)
3917 DEFHOOK
3918 (estimated_poly_value,
3919 "Return an estimate of the runtime value of @var{val}, for use in\n\
3920 things like cost calculations or profiling frequencies. @var{kind} is used\n\
3921 to ask for the minimum, maximum, and likely estimates of the value through\n\
3922 the @code{POLY_VALUE_MIN}, @code{POLY_VALUE_MAX} and\n\
3923 @code{POLY_VALUE_LIKELY} values. The default\n\
3924 implementation returns the lowest possible value of @var{val}.",
3925 HOST_WIDE_INT, (poly_int64 val, poly_value_estimate_kind kind),
3926 default_estimated_poly_value)
3928 /* Permit speculative instructions in delay slots during delayed-branch
3929 scheduling. */
3930 DEFHOOK
3931 (no_speculation_in_delay_slots_p,
3932 "This predicate controls the use of the eager delay slot filler to disallow\n\
3933 speculatively executed instructions being placed in delay slots. Targets\n\
3934 such as certain MIPS architectures possess both branches with and without\n\
3935 delay slots. As the eager delay slot filler can decrease performance,\n\
3936 disabling it is beneficial when ordinary branches are available. Use of\n\
3937 delay slot branches filled using the basic filler is often still desirable\n\
3938 as the delay slot can hide a pipeline bubble.",
3939 bool, (void),
3940 hook_bool_void_false)
3942 /* Return where to allocate pseudo for a given hard register initial value. */
3943 DEFHOOK
3944 (allocate_initial_value,
3945 "\n\
3946 When the initial value of a hard register has been copied in a pseudo\n\
3947 register, it is often not necessary to actually allocate another register\n\
3948 to this pseudo register, because the original hard register or a stack slot\n\
3949 it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}\n\
3950 is called at the start of register allocation once for each hard register\n\
3951 that had its initial value copied by using\n\
3952 @code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.\n\
3953 Possible values are @code{NULL_RTX}, if you don't want\n\
3954 to do any special allocation, a @code{REG} rtx---that would typically be\n\
3955 the hard register itself, if it is known not to be clobbered---or a\n\
3956 @code{MEM}.\n\
3957 If you are returning a @code{MEM}, this is only a hint for the allocator;\n\
3958 it might decide to use another register anyways.\n\
3959 You may use @code{current_function_is_leaf} or \n\
3960 @code{REG_N_SETS} in the hook to determine if the hard\n\
3961 register in question will not be clobbered.\n\
3962 The default value of this hook is @code{NULL}, which disables any special\n\
3963 allocation.",
3964 rtx, (rtx hard_reg), NULL)
3966 /* Return nonzero if evaluating UNSPEC X might cause a trap.
3967 FLAGS has the same meaning as in rtlanal.cc: may_trap_p_1. */
3968 DEFHOOK
3969 (unspec_may_trap_p,
3970 "This target hook returns nonzero if @var{x}, an @code{unspec} or\n\
3971 @code{unspec_volatile} operation, might cause a trap. Targets can use\n\
3972 this hook to enhance precision of analysis for @code{unspec} and\n\
3973 @code{unspec_volatile} operations. You may call @code{may_trap_p_1}\n\
3974 to analyze inner elements of @var{x} in which case @var{flags} should be\n\
3975 passed along.",
3976 int, (const_rtx x, unsigned flags),
3977 default_unspec_may_trap_p)
3979 /* Given a register, this hook should return a parallel of registers
3980 to represent where to find the register pieces. Define this hook
3981 if the register and its mode are represented in Dwarf in
3982 non-contiguous locations, or if the register should be
3983 represented in more than one register in Dwarf. Otherwise, this
3984 hook should return NULL_RTX. */
3985 DEFHOOK
3986 (dwarf_register_span,
3987 "Given a register, this hook should return a parallel of registers to\n\
3988 represent where to find the register pieces. Define this hook if the\n\
3989 register and its mode are represented in Dwarf in non-contiguous\n\
3990 locations, or if the register should be represented in more than one\n\
3991 register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.\n\
3992 If not defined, the default is to return @code{NULL_RTX}.",
3993 rtx, (rtx reg),
3994 hook_rtx_rtx_null)
3996 /* Given a register return the mode of the corresponding DWARF frame
3997 register. */
3998 DEFHOOK
3999 (dwarf_frame_reg_mode,
4000 "Given a register, this hook should return the mode which the\n\
4001 corresponding Dwarf frame register should have. This is normally\n\
4002 used to return a smaller mode than the raw mode to prevent call\n\
4003 clobbered parts of a register altering the frame register size",
4004 machine_mode, (int regno),
4005 default_dwarf_frame_reg_mode)
4007 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
4008 entries not corresponding directly to registers below
4009 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
4010 code, given the address of the table. */
4011 DEFHOOK
4012 (init_dwarf_reg_sizes_extra,
4013 "If some registers are represented in Dwarf-2 unwind information in\n\
4014 multiple pieces, define this hook to fill in information about the\n\
4015 sizes of those pieces in the table used by the unwinder at runtime.\n\
4016 It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after\n\
4017 filling in a single size corresponding to each hard register;\n\
4018 @var{address} is the address of the table.",
4019 void, (tree address),
4020 hook_void_tree)
4022 /* Fetch the fixed register(s) which hold condition codes, for
4023 targets where it makes sense to look for duplicate assignments to
4024 the condition codes. This should return true if there is such a
4025 register, false otherwise. The arguments should be set to the
4026 fixed register numbers. Up to two condition code registers are
4027 supported. If there is only one for this target, the int pointed
4028 at by the second argument should be set to -1. */
4029 DEFHOOK
4030 (fixed_condition_code_regs,
4031 "On targets which use a hard\n\
4032 register rather than a pseudo-register to hold condition codes, the\n\
4033 regular CSE passes are often not able to identify cases in which the\n\
4034 hard register is set to a common value. Use this hook to enable a\n\
4035 small pass which optimizes such cases. This hook should return true\n\
4036 to enable this pass, and it should set the integers to which its\n\
4037 arguments point to the hard register numbers used for condition codes.\n\
4038 When there is only one such register, as is true on most systems, the\n\
4039 integer pointed to by @var{p2} should be set to\n\
4040 @code{INVALID_REGNUM}.\n\
4042 The default version of this hook returns false.",
4043 bool, (unsigned int *p1, unsigned int *p2),
4044 hook_bool_uintp_uintp_false)
4046 /* If two condition code modes are compatible, return a condition
4047 code mode which is compatible with both, such that a comparison
4048 done in the returned mode will work for both of the original
4049 modes. If the condition code modes are not compatible, return
4050 VOIDmode. */
4051 DEFHOOK
4052 (cc_modes_compatible,
4053 "On targets which use multiple condition code modes in class\n\
4054 @code{MODE_CC}, it is sometimes the case that a comparison can be\n\
4055 validly done in more than one mode. On such a system, define this\n\
4056 target hook to take two mode arguments and to return a mode in which\n\
4057 both comparisons may be validly done. If there is no such mode,\n\
4058 return @code{VOIDmode}.\n\
4060 The default version of this hook checks whether the modes are the\n\
4061 same. If they are, it returns that mode. If they are different, it\n\
4062 returns @code{VOIDmode}.",
4063 machine_mode, (machine_mode m1, machine_mode m2),
4064 default_cc_modes_compatible)
4066 /* Do machine-dependent code transformations. Called just before
4067 delayed-branch scheduling. */
4068 DEFHOOK
4069 (machine_dependent_reorg,
4070 "If non-null, this hook performs a target-specific pass over the\n\
4071 instruction stream. The compiler will run it at all optimization levels,\n\
4072 just before the point at which it normally does delayed-branch scheduling.\n\
4074 The exact purpose of the hook varies from target to target. Some use\n\
4075 it to do transformations that are necessary for correctness, such as\n\
4076 laying out in-function constant pools or avoiding hardware hazards.\n\
4077 Others use it as an opportunity to do some machine-dependent optimizations.\n\
4079 You need not implement the hook if it has nothing to do. The default\n\
4080 definition is null.",
4081 void, (void), NULL)
4083 /* Create the __builtin_va_list type. */
4084 DEFHOOK
4085 (build_builtin_va_list,
4086 "This hook returns a type node for @code{va_list} for the target.\n\
4087 The default version of the hook returns @code{void*}.",
4088 tree, (void),
4089 std_build_builtin_va_list)
4091 /* Enumerate the va list variants. */
4092 DEFHOOK
4093 (enum_va_list_p,
4094 "This target hook is used in function @code{c_common_nodes_and_builtins}\n\
4095 to iterate through the target specific builtin types for va_list. The\n\
4096 variable @var{idx} is used as iterator. @var{pname} has to be a pointer\n\
4097 to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed\n\
4098 variable.\n\
4099 The arguments @var{pname} and @var{ptree} are used to store the result of\n\
4100 this macro and are set to the name of the va_list builtin type and its\n\
4101 internal type.\n\
4102 If the return value of this macro is zero, then there is no more element.\n\
4103 Otherwise the @var{IDX} should be increased for the next call of this\n\
4104 macro to iterate through all types.",
4105 int, (int idx, const char **pname, tree *ptree),
4106 NULL)
4108 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
4109 DEFHOOK
4110 (fn_abi_va_list,
4111 "This hook returns the va_list type of the calling convention specified by\n\
4112 @var{fndecl}.\n\
4113 The default version of this hook returns @code{va_list_type_node}.",
4114 tree, (tree fndecl),
4115 std_fn_abi_va_list)
4117 /* Get the __builtin_va_list type dependent on input type. */
4118 DEFHOOK
4119 (canonical_va_list_type,
4120 "This hook returns the va_list type of the calling convention specified by the\n\
4121 type of @var{type}. If @var{type} is not a valid va_list type, it returns\n\
4122 @code{NULL_TREE}.",
4123 tree, (tree type),
4124 std_canonical_va_list_type)
4126 /* ??? Documenting this hook requires a GFDL license grant. */
4127 DEFHOOK_UNDOC
4128 (expand_builtin_va_start,
4129 "Expand the @code{__builtin_va_start} builtin.",
4130 void, (tree valist, rtx nextarg), NULL)
4132 /* Gimplifies a VA_ARG_EXPR. */
4133 DEFHOOK
4134 (gimplify_va_arg_expr,
4135 "This hook performs target-specific gimplification of\n\
4136 @code{VA_ARG_EXPR}. The first two parameters correspond to the\n\
4137 arguments to @code{va_arg}; the latter two are as in\n\
4138 @code{gimplify.cc:gimplify_expr}.",
4139 tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
4140 std_gimplify_va_arg_expr)
4142 /* Validity-checking routines for PCH files, target-specific.
4143 get_pch_validity returns a pointer to the data to be stored,
4144 and stores the size in its argument. pch_valid_p gets the same
4145 information back and returns NULL if the PCH is valid,
4146 or an error message if not. */
4147 DEFHOOK
4148 (get_pch_validity,
4149 "This hook returns a pointer to the data needed by\n\
4150 @code{TARGET_PCH_VALID_P} and sets\n\
4151 @samp{*@var{sz}} to the size of the data in bytes.",
4152 void *, (size_t *sz),
4153 default_get_pch_validity)
4155 DEFHOOK
4156 (pch_valid_p,
4157 "This hook checks whether the options used to create a PCH file are\n\
4158 compatible with the current settings. It returns @code{NULL}\n\
4159 if so and a suitable error message if not. Error messages will\n\
4160 be presented to the user and must be localized using @samp{_(@var{msg})}.\n\
4162 @var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}\n\
4163 when the PCH file was created and @var{sz} is the size of that data in bytes.\n\
4164 It's safe to assume that the data was created by the same version of the\n\
4165 compiler, so no format checking is needed.\n\
4167 The default definition of @code{default_pch_valid_p} should be\n\
4168 suitable for most targets.",
4169 const char *, (const void *data, size_t sz),
4170 default_pch_valid_p)
4172 DEFHOOK
4173 (prepare_pch_save,
4174 "Called before writing out a PCH file. If the target has some\n\
4175 garbage-collected data that needs to be in a particular state on PCH loads,\n\
4176 it can use this hook to enforce that state. Very few targets need\n\
4177 to do anything here.",
4178 void, (void),
4179 hook_void_void)
4181 /* If nonnull, this function checks whether a PCH file with the
4182 given set of target flags can be used. It returns NULL if so,
4183 otherwise it returns an error message. */
4184 DEFHOOK
4185 (check_pch_target_flags,
4186 "If this hook is nonnull, the default implementation of\n\
4187 @code{TARGET_PCH_VALID_P} will use it to check for compatible values\n\
4188 of @code{target_flags}. @var{pch_flags} specifies the value that\n\
4189 @code{target_flags} had when the PCH file was created. The return\n\
4190 value is the same as for @code{TARGET_PCH_VALID_P}.",
4191 const char *, (int pch_flags), NULL)
4193 /* True if the compiler should give an enum type only as many
4194 bytes as it takes to represent the range of possible values of
4195 that type. */
4196 DEFHOOK
4197 (default_short_enums,
4198 "This target hook should return true if the compiler should give an\n\
4199 @code{enum} type only as many bytes as it takes to represent the range\n\
4200 of possible values of that type. It should return false if all\n\
4201 @code{enum} types should be allocated like @code{int}.\n\
4203 The default is to return false.",
4204 bool, (void),
4205 hook_bool_void_false)
4207 /* This target hook returns an rtx that is used to store the address
4208 of the current frame into the built-in setjmp buffer. */
4209 DEFHOOK
4210 (builtin_setjmp_frame_value,
4211 "This target hook should return an rtx that is used to store\n\
4212 the address of the current frame into the built in @code{setjmp} buffer.\n\
4213 The default value, @code{virtual_stack_vars_rtx}, is correct for most\n\
4214 machines. One reason you may need to define this target hook is if\n\
4215 @code{hard_frame_pointer_rtx} is the appropriate value on your machine.",
4216 rtx, (void),
4217 default_builtin_setjmp_frame_value)
4219 /* This target hook should manipulate the outputs, inputs, constraints,
4220 and clobbers the port wishes for pre-processing the asm. */
4221 DEFHOOK
4222 (md_asm_adjust,
4223 "This target hook may add @dfn{clobbers} to @var{clobbers} and\n\
4224 @var{clobbered_regs} for any hard regs the port wishes to automatically\n\
4225 clobber for an asm. The @var{outputs} and @var{inputs} may be inspected\n\
4226 to avoid clobbering a register that is already used by the asm. @var{loc}\n\
4227 is the source location of the asm.\n\
4229 It may modify the @var{outputs}, @var{inputs}, @var{input_modes}, and\n\
4230 @var{constraints} as necessary for other pre-processing. In this case the\n\
4231 return value is a sequence of insns to emit after the asm. Note that\n\
4232 changes to @var{inputs} must be accompanied by the corresponding changes\n\
4233 to @var{input_modes}.",
4234 rtx_insn *,
4235 (vec<rtx>& outputs, vec<rtx>& inputs, vec<machine_mode>& input_modes,
4236 vec<const char *>& constraints, vec<rtx>& clobbers,
4237 HARD_REG_SET& clobbered_regs, location_t loc),
4238 NULL)
4240 /* This target hook allows the backend to specify a calling convention
4241 in the debug information. This function actually returns an
4242 enum dwarf_calling_convention, but because of forward declarations
4243 and not wanting to include dwarf2.h everywhere target.h is included
4244 the function is being declared as an int. */
4245 DEFHOOK
4246 (dwarf_calling_convention,
4247 "Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to\n\
4248 be emitted for each function. Instead of an integer return the enum\n\
4249 value for the @code{DW_CC_} tag.",
4250 int, (const_tree function),
4251 hook_int_const_tree_0)
4253 /* This target hook allows the backend to emit frame-related insns that
4254 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
4255 engine will invoke it on insns of the form
4256 (set (reg) (unspec [...] UNSPEC_INDEX))
4258 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
4259 to let the backend emit the call frame instructions. */
4260 DEFHOOK
4261 (dwarf_handle_frame_unspec,
4262 "This target hook allows the backend to emit frame-related insns that\n\
4263 contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging\n\
4264 info engine will invoke it on insns of the form\n\
4265 @smallexample\n\
4266 (set (reg) (unspec [@dots{}] UNSPEC_INDEX))\n\
4267 @end smallexample\n\
4268 and\n\
4269 @smallexample\n\
4270 (set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).\n\
4271 @end smallexample\n\
4272 to let the backend emit the call frame instructions. @var{label} is\n\
4273 the CFI label attached to the insn, @var{pattern} is the pattern of\n\
4274 the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.",
4275 void, (const char *label, rtx pattern, int index), NULL)
4277 DEFHOOK
4278 (dwarf_poly_indeterminate_value,
4279 "Express the value of @code{poly_int} indeterminate @var{i} as a DWARF\n\
4280 expression, with @var{i} counting from 1. Return the number of a DWARF\n\
4281 register @var{R} and set @samp{*@var{factor}} and @samp{*@var{offset}} such\n\
4282 that the value of the indeterminate is:\n\
4283 @smallexample\n\
4284 value_of(@var{R}) / @var{factor} - @var{offset}\n\
4285 @end smallexample\n\
4287 A target only needs to define this hook if it sets\n\
4288 @samp{NUM_POLY_INT_COEFFS} to a value greater than 1.",
4289 unsigned int, (unsigned int i, unsigned int *factor, int *offset),
4290 default_dwarf_poly_indeterminate_value)
4292 /* ??? Documenting this hook requires a GFDL license grant. */
4293 DEFHOOK_UNDOC
4294 (stdarg_optimize_hook,
4295 "Perform architecture specific checking of statements gimplified\
4296 from @code{VA_ARG_EXPR}. @var{stmt} is the statement. Returns true if\
4297 the statement doesn't need to be checked for @code{va_list} references.",
4298 bool, (struct stdarg_info *ai, const gimple *stmt), NULL)
4300 /* This target hook allows the operating system to override the DECL
4301 that represents the external variable that contains the stack
4302 protection guard variable. The type of this DECL is ptr_type_node. */
4303 DEFHOOK
4304 (stack_protect_guard,
4305 "This hook returns a @code{DECL} node for the external variable to use\n\
4306 for the stack protection guard. This variable is initialized by the\n\
4307 runtime to some random value and is used to initialize the guard value\n\
4308 that is placed at the top of the local stack frame. The type of this\n\
4309 variable must be @code{ptr_type_node}.\n\
4311 The default version of this hook creates a variable called\n\
4312 @samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.",
4313 tree, (void),
4314 default_stack_protect_guard)
4316 /* This target hook allows the operating system to override the CALL_EXPR
4317 that is invoked when a check vs the guard variable fails. */
4318 DEFHOOK
4319 (stack_protect_fail,
4320 "This hook returns a @code{CALL_EXPR} that alerts the runtime that the\n\
4321 stack protect guard variable has been modified. This expression should\n\
4322 involve a call to a @code{noreturn} function.\n\
4324 The default version of this hook invokes a function called\n\
4325 @samp{__stack_chk_fail}, taking no arguments. This function is\n\
4326 normally defined in @file{libgcc2.c}.",
4327 tree, (void),
4328 default_external_stack_protect_fail)
4330 /* This target hook allows the operating system to disable the default stack
4331 protector runtime support. */
4332 DEFHOOK
4333 (stack_protect_runtime_enabled_p,
4334 "Returns true if the target wants GCC's default stack protect runtime support,\n\
4335 otherwise return false. The default implementation always returns true.",
4336 bool, (void),
4337 hook_bool_void_true)
4339 DEFHOOK
4340 (have_speculation_safe_value,
4341 "This hook is used to determine the level of target support for\n\
4342 @code{__builtin_speculation_safe_value}. If called with an argument\n\
4343 of false, it returns true if the target has been modified to support\n\
4344 this builtin. If called with an argument of true, it returns true\n\
4345 if the target requires active mitigation execution might be speculative.\n\
4347 The default implementation returns false if the target does not define\n\
4348 a pattern named @code{speculation_barrier}. Else it returns true\n\
4349 for the first case and whether the pattern is enabled for the current\n\
4350 compilation for the second case.\n\
4352 For targets that have no processors that can execute instructions\n\
4353 speculatively an alternative implemenation of this hook is available:\n\
4354 simply redefine this hook to @code{speculation_safe_value_not_needed}\n\
4355 along with your other target hooks.",
4356 bool, (bool active), default_have_speculation_safe_value)
4358 DEFHOOK
4359 (speculation_safe_value,
4360 "This target hook can be used to generate a target-specific code\n\
4361 sequence that implements the @code{__builtin_speculation_safe_value}\n\
4362 built-in function. The function must always return @var{val} in\n\
4363 @var{result} in mode @var{mode} when the cpu is not executing\n\
4364 speculatively, but must never return that when speculating until it\n\
4365 is known that the speculation will not be unwound. The hook supports\n\
4366 two primary mechanisms for implementing the requirements. The first\n\
4367 is to emit a speculation barrier which forces the processor to wait\n\
4368 until all prior speculative operations have been resolved; the second\n\
4369 is to use a target-specific mechanism that can track the speculation\n\
4370 state and to return @var{failval} if it can determine that\n\
4371 speculation must be unwound at a later time.\n\
4373 The default implementation simply copies @var{val} to @var{result} and\n\
4374 emits a @code{speculation_barrier} instruction if that is defined.",
4375 rtx, (machine_mode mode, rtx result, rtx val, rtx failval),
4376 default_speculation_safe_value)
4378 DEFHOOK
4379 (predict_doloop_p,
4380 "Return true if we can predict it is possible to use a low-overhead loop\n\
4381 for a particular loop. The parameter @var{loop} is a pointer to the loop.\n\
4382 This target hook is required only when the target supports low-overhead\n\
4383 loops, and will help ivopts to make some decisions.\n\
4384 The default version of this hook returns false.",
4385 bool, (class loop *loop),
4386 default_predict_doloop_p)
4388 DEFHOOKPOD
4389 (have_count_reg_decr_p,
4390 "Return true if the target supports hardware count register for decrement\n\
4391 and branch.\n\
4392 The default value is false.",
4393 bool, false)
4395 DEFHOOKPOD
4396 (doloop_cost_for_generic,
4397 "One IV candidate dedicated for doloop is introduced in IVOPTs, we can\n\
4398 calculate the computation cost of adopting it to any generic IV use by\n\
4399 function get_computation_cost as before. But for targets which have\n\
4400 hardware count register support for decrement and branch, it may have to\n\
4401 move IV value from hardware count register to general purpose register\n\
4402 while doloop IV candidate is used for generic IV uses. It probably takes\n\
4403 expensive penalty. This hook allows target owners to define the cost for\n\
4404 this especially for generic IV uses.\n\
4405 The default value is zero.",
4406 int64_t, 0)
4408 DEFHOOKPOD
4409 (doloop_cost_for_address,
4410 "One IV candidate dedicated for doloop is introduced in IVOPTs, we can\n\
4411 calculate the computation cost of adopting it to any address IV use by\n\
4412 function get_computation_cost as before. But for targets which have\n\
4413 hardware count register support for decrement and branch, it may have to\n\
4414 move IV value from hardware count register to general purpose register\n\
4415 while doloop IV candidate is used for address IV uses. It probably takes\n\
4416 expensive penalty. This hook allows target owners to define the cost for\n\
4417 this escpecially for address IV uses.\n\
4418 The default value is zero.",
4419 int64_t, 0)
4421 DEFHOOK
4422 (can_use_doloop_p,
4423 "Return true if it is possible to use low-overhead loops (@code{doloop_end}\n\
4424 and @code{doloop_begin}) for a particular loop. @var{iterations} gives the\n\
4425 exact number of iterations, or 0 if not known. @var{iterations_max} gives\n\
4426 the maximum number of iterations, or 0 if not known. @var{loop_depth} is\n\
4427 the nesting depth of the loop, with 1 for innermost loops, 2 for loops that\n\
4428 contain innermost loops, and so on. @var{entered_at_top} is true if the\n\
4429 loop is only entered from the top.\n\
4431 This hook is only used if @code{doloop_end} is available. The default\n\
4432 implementation returns true. You can use @code{can_use_doloop_if_innermost}\n\
4433 if the loop must be the innermost, and if there are no other restrictions.",
4434 bool, (const widest_int &iterations, const widest_int &iterations_max,
4435 unsigned int loop_depth, bool entered_at_top),
4436 hook_bool_wint_wint_uint_bool_true)
4438 /* Returns NULL if target supports the insn within a doloop block,
4439 otherwise it returns an error message. */
4440 DEFHOOK
4441 (invalid_within_doloop,
4442 "\n\
4443 Take an instruction in @var{insn} and return NULL if it is valid within a\n\
4444 low-overhead loop, otherwise return a string explaining why doloop\n\
4445 could not be applied.\n\
4447 Many targets use special registers for low-overhead looping. For any\n\
4448 instruction that clobbers these this function should return a string indicating\n\
4449 the reason why the doloop could not be applied.\n\
4450 By default, the RTL loop optimizer does not use a present doloop pattern for\n\
4451 loops containing function calls or branch on table instructions.",
4452 const char *, (const rtx_insn *insn),
4453 default_invalid_within_doloop)
4455 /* Returns the machine mode which the target prefers for doloop IV. */
4456 DEFHOOK
4457 (preferred_doloop_mode,
4458 "This hook takes a @var{mode} for a doloop IV, where @code{mode} is the\n\
4459 original mode for the operation. If the target prefers an alternate\n\
4460 @code{mode} for the operation, then this hook should return that mode;\n\
4461 otherwise the original @code{mode} should be returned. For example, on a\n\
4462 64-bit target, @code{DImode} might be preferred over @code{SImode}. Both the\n\
4463 original and the returned modes should be @code{MODE_INT}.",
4464 machine_mode,
4465 (machine_mode mode),
4466 default_preferred_doloop_mode)
4468 /* Returns true for a legitimate combined insn. */
4469 DEFHOOK
4470 (legitimate_combined_insn,
4471 "Take an instruction in @var{insn} and return @code{false} if the instruction\n\
4472 is not appropriate as a combination of two or more instructions. The\n\
4473 default is to accept all instructions.",
4474 bool, (rtx_insn *insn),
4475 hook_bool_rtx_insn_true)
4477 DEFHOOK
4478 (valid_dllimport_attribute_p,
4479 "@var{decl} is a variable or function with @code{__attribute__((dllimport))}\n\
4480 specified. Use this hook if the target needs to add extra validation\n\
4481 checks to @code{handle_dll_attribute}.",
4482 bool, (const_tree decl),
4483 hook_bool_const_tree_true)
4485 /* If non-zero, align constant anchors in CSE to a multiple of this
4486 value. */
4487 DEFHOOKPOD
4488 (const_anchor,
4489 "On some architectures it can take multiple instructions to synthesize\n\
4490 a constant. If there is another constant already in a register that\n\
4491 is close enough in value then it is preferable that the new constant\n\
4492 is computed from this register using immediate addition or\n\
4493 subtraction. We accomplish this through CSE. Besides the value of\n\
4494 the constant we also add a lower and an upper constant anchor to the\n\
4495 available expressions. These are then queried when encountering new\n\
4496 constants. The anchors are computed by rounding the constant up and\n\
4497 down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.\n\
4498 @code{TARGET_CONST_ANCHOR} should be the maximum positive value\n\
4499 accepted by immediate-add plus one. We currently assume that the\n\
4500 value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on\n\
4501 MIPS, where add-immediate takes a 16-bit signed value,\n\
4502 @code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value\n\
4503 is zero, which disables this optimization.",
4504 unsigned HOST_WIDE_INT, 0)
4506 /* Defines, which target-dependent bits (upper 16) are used by port */
4507 DEFHOOK
4508 (memmodel_check,
4509 "Validate target specific memory model mask bits. When NULL no target specific\n\
4510 memory model bits are allowed.",
4511 unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)
4513 /* Defines an offset bitwise ored into shifted address to get corresponding
4514 Address Sanitizer shadow address, or -1 if Address Sanitizer is not
4515 supported by the target. */
4516 DEFHOOK
4517 (asan_shadow_offset,
4518 "Return the offset bitwise ored into shifted address to get corresponding\n\
4519 Address Sanitizer shadow memory address. NULL if Address Sanitizer is not\n\
4520 supported by the target. May return 0 if Address Sanitizer is not supported\n\
4521 by a subtarget.",
4522 unsigned HOST_WIDE_INT, (void),
4523 NULL)
4525 /* Functions relating to calls - argument passing, returns, etc. */
4526 /* Members of struct call have no special macro prefix. */
4527 HOOK_VECTOR (TARGET_CALLS, calls)
4529 DEFHOOK
4530 (promote_function_mode,
4531 "Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or\n\
4532 function return values. The target hook should return the new mode\n\
4533 and possibly change @code{*@var{punsignedp}} if the promotion should\n\
4534 change signedness. This function is called only for scalar @emph{or\n\
4535 pointer} types.\n\
4537 @var{for_return} allows to distinguish the promotion of arguments and\n\
4538 return values. If it is @code{1}, a return value is being promoted and\n\
4539 @code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.\n\
4540 If it is @code{2}, the returned mode should be that of the register in\n\
4541 which an incoming parameter is copied, or the outgoing result is computed;\n\
4542 then the hook should return the same mode as @code{promote_mode}, though\n\
4543 the signedness may be different.\n\
4545 @var{type} can be NULL when promoting function arguments of libcalls.\n\
4547 The default is to not promote arguments and return values. You can\n\
4548 also define the hook to @code{default_promote_function_mode_always_promote}\n\
4549 if you would like to apply the same rules given by @code{PROMOTE_MODE}.",
4550 machine_mode, (const_tree type, machine_mode mode, int *punsignedp,
4551 const_tree funtype, int for_return),
4552 default_promote_function_mode)
4554 DEFHOOK
4555 (promote_prototypes,
4556 "This target hook returns @code{true} if an argument declared in a\n\
4557 prototype as an integral type smaller than @code{int} should actually be\n\
4558 passed as an @code{int}. In addition to avoiding errors in certain\n\
4559 cases of mismatch, it also makes for better code on certain machines.\n\
4560 The default is to not promote prototypes.",
4561 bool, (const_tree fntype),
4562 hook_bool_const_tree_false)
4564 DEFHOOK
4565 (struct_value_rtx,
4566 "This target hook should return the location of the structure value\n\
4567 address (normally a @code{mem} or @code{reg}), or 0 if the address is\n\
4568 passed as an ``invisible'' first argument. Note that @var{fndecl} may\n\
4569 be @code{NULL}, for libcalls. You do not need to define this target\n\
4570 hook if the address is always passed as an ``invisible'' first\n\
4571 argument.\n\
4573 On some architectures the place where the structure value address\n\
4574 is found by the called function is not the same place that the\n\
4575 caller put it. This can be due to register windows, or it could\n\
4576 be because the function prologue moves it to a different place.\n\
4577 @var{incoming} is @code{1} or @code{2} when the location is needed in\n\
4578 the context of the called function, and @code{0} in the context of\n\
4579 the caller.\n\
4581 If @var{incoming} is nonzero and the address is to be found on the\n\
4582 stack, return a @code{mem} which refers to the frame pointer. If\n\
4583 @var{incoming} is @code{2}, the result is being used to fetch the\n\
4584 structure value address at the beginning of a function. If you need\n\
4585 to emit adjusting code, you should do it at this point.",
4586 rtx, (tree fndecl, int incoming),
4587 hook_rtx_tree_int_null)
4589 DEFHOOKPOD
4590 (omit_struct_return_reg,
4591 "Normally, when a function returns a structure by memory, the address\n\
4592 is passed as an invisible pointer argument, but the compiler also\n\
4593 arranges to return the address from the function like it would a normal\n\
4594 pointer return value. Define this to true if that behavior is\n\
4595 undesirable on your target.",
4596 bool, false)
4598 DEFHOOK
4599 (return_in_memory,
4600 "This target hook should return a nonzero value to say to return the\n\
4601 function value in memory, just as large structures are always returned.\n\
4602 Here @var{type} will be the data type of the value, and @var{fntype}\n\
4603 will be the type of the function doing the returning, or @code{NULL} for\n\
4604 libcalls.\n\
4606 Note that values of mode @code{BLKmode} must be explicitly handled\n\
4607 by this function. Also, the option @option{-fpcc-struct-return}\n\
4608 takes effect regardless of this macro. On most systems, it is\n\
4609 possible to leave the hook undefined; this causes a default\n\
4610 definition to be used, whose value is the constant 1 for @code{BLKmode}\n\
4611 values, and 0 otherwise.\n\
4613 Do not use this hook to indicate that structures and unions should always\n\
4614 be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}\n\
4615 to indicate this.",
4616 bool, (const_tree type, const_tree fntype),
4617 default_return_in_memory)
4619 DEFHOOK
4620 (return_in_msb,
4621 "This hook should return true if values of type @var{type} are returned\n\
4622 at the most significant end of a register (in other words, if they are\n\
4623 padded at the least significant end). You can assume that @var{type}\n\
4624 is returned in a register; the caller is required to check this.\n\
4626 Note that the register provided by @code{TARGET_FUNCTION_VALUE} must\n\
4627 be able to hold the complete return value. For example, if a 1-, 2-\n\
4628 or 3-byte structure is returned at the most significant end of a\n\
4629 4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an\n\
4630 @code{SImode} rtx.",
4631 bool, (const_tree type),
4632 hook_bool_const_tree_false)
4634 /* Return true if a parameter must be passed by reference. TYPE may
4635 be null if this is a libcall. CA may be null if this query is
4636 from __builtin_va_arg. */
4637 DEFHOOK
4638 (pass_by_reference,
4639 "This target hook should return @code{true} if argument @var{arg} at the\n\
4640 position indicated by @var{cum} should be passed by reference. This\n\
4641 predicate is queried after target independent reasons for being\n\
4642 passed by reference, such as @code{TREE_ADDRESSABLE (@var{arg}.type)}.\n\
4644 If the hook returns true, a copy of that argument is made in memory and a\n\
4645 pointer to the argument is passed instead of the argument itself.\n\
4646 The pointer is passed in whatever way is appropriate for passing a pointer\n\
4647 to that type.",
4648 bool,
4649 (cumulative_args_t cum, const function_arg_info &arg),
4650 hook_bool_CUMULATIVE_ARGS_arg_info_false)
4652 DEFHOOK
4653 (expand_builtin_saveregs,
4654 "If defined, this hook produces the machine-specific code for a call to\n\
4655 @code{__builtin_saveregs}. This code will be moved to the very\n\
4656 beginning of the function, before any parameter access are made. The\n\
4657 return value of this function should be an RTX that contains the value\n\
4658 to use as the return of @code{__builtin_saveregs}.",
4659 rtx, (void),
4660 default_expand_builtin_saveregs)
4662 /* Returns pretend_argument_size. */
4663 DEFHOOK
4664 (setup_incoming_varargs,
4665 "This target hook offers an alternative to using\n\
4666 @code{__builtin_saveregs} and defining the hook\n\
4667 @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous\n\
4668 register arguments into the stack so that all the arguments appear to\n\
4669 have been passed consecutively on the stack. Once this is done, you can\n\
4670 use the standard implementation of varargs that works for machines that\n\
4671 pass all their arguments on the stack.\n\
4673 The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data\n\
4674 structure, containing the values that are obtained after processing the\n\
4675 named arguments. The argument @var{arg} describes the last of these named\n\
4676 arguments.\n\
4678 The target hook should do two things: first, push onto the stack all the\n\
4679 argument registers @emph{not} used for the named arguments, and second,\n\
4680 store the size of the data thus pushed into the @code{int}-valued\n\
4681 variable pointed to by @var{pretend_args_size}. The value that you\n\
4682 store here will serve as additional offset for setting up the stack\n\
4683 frame.\n\
4685 Because you must generate code to push the anonymous arguments at\n\
4686 compile time without knowing their data types,\n\
4687 @code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that\n\
4688 have just a single category of argument register and use it uniformly\n\
4689 for all data types.\n\
4691 If the argument @var{second_time} is nonzero, it means that the\n\
4692 arguments of the function are being analyzed for the second time. This\n\
4693 happens for an inline function, which is not actually compiled until the\n\
4694 end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should\n\
4695 not generate any instructions in this case.",
4696 void, (cumulative_args_t args_so_far, const function_arg_info &arg,
4697 int *pretend_args_size, int second_time),
4698 default_setup_incoming_varargs)
4700 DEFHOOK
4701 (call_args,
4702 "While generating RTL for a function call, this target hook is invoked once\n\
4703 for each argument passed to the function, either a register returned by\n\
4704 @code{TARGET_FUNCTION_ARG} or a memory location. It is called just\n\
4705 before the point where argument registers are stored. The type of the\n\
4706 function to be called is also passed as the second argument; it is\n\
4707 @code{NULL_TREE} for libcalls. The @code{TARGET_END_CALL_ARGS} hook is\n\
4708 invoked just after the code to copy the return reg has been emitted.\n\
4709 This functionality can be used to perform special setup of call argument\n\
4710 registers if a target needs it.\n\
4711 For functions without arguments, the hook is called once with @code{pc_rtx}\n\
4712 passed instead of an argument register.\n\
4713 Most ports do not need to implement anything for this hook.",
4714 void, (rtx, tree),
4715 hook_void_rtx_tree)
4717 DEFHOOK
4718 (end_call_args,
4719 "This target hook is invoked while generating RTL for a function call,\n\
4720 just after the point where the return reg is copied into a pseudo. It\n\
4721 signals that all the call argument and return registers for the just\n\
4722 emitted call are now no longer in use.\n\
4723 Most ports do not need to implement anything for this hook.",
4724 void, (void),
4725 hook_void_void)
4727 DEFHOOK
4728 (push_argument,
4729 "This target hook returns @code{true} if push instructions will be\n\
4730 used to pass outgoing arguments. When the push instruction usage is\n\
4731 optional, @var{npush} is nonzero to indicate the number of bytes to\n\
4732 push. Otherwise, @var{npush} is zero. If the target machine does not\n\
4733 have a push instruction or push instruction should be avoided,\n\
4734 @code{false} should be returned. That directs GCC to use an alternate\n\
4735 strategy: to allocate the entire argument block and then store the\n\
4736 arguments into it. If this target hook may return @code{true},\n\
4737 @code{PUSH_ROUNDING} must be defined.",
4738 bool, (unsigned int npush),
4739 default_push_argument)
4741 DEFHOOK
4742 (strict_argument_naming,
4743 "Define this hook to return @code{true} if the location where a function\n\
4744 argument is passed depends on whether or not it is a named argument.\n\
4746 This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}\n\
4747 is set for varargs and stdarg functions. If this hook returns\n\
4748 @code{true}, the @var{named} argument is always true for named\n\
4749 arguments, and false for unnamed arguments. If it returns @code{false},\n\
4750 but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},\n\
4751 then all arguments are treated as named. Otherwise, all named arguments\n\
4752 except the last are treated as named.\n\
4754 You need not define this hook if it always returns @code{false}.",
4755 bool, (cumulative_args_t ca),
4756 hook_bool_CUMULATIVE_ARGS_false)
4758 /* Returns true if we should use
4759 targetm.calls.setup_incoming_varargs() and/or
4760 targetm.calls.strict_argument_naming(). */
4761 DEFHOOK
4762 (pretend_outgoing_varargs_named,
4763 "If you need to conditionally change ABIs so that one works with\n\
4764 @code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither\n\
4765 @code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was\n\
4766 defined, then define this hook to return @code{true} if\n\
4767 @code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.\n\
4768 Otherwise, you should not define this hook.",
4769 bool, (cumulative_args_t ca),
4770 default_pretend_outgoing_varargs_named)
4772 /* Given a complex type T, return true if a parameter of type T
4773 should be passed as two scalars. */
4774 DEFHOOK
4775 (split_complex_arg,
4776 "This hook should return true if parameter of type @var{type} are passed\n\
4777 as two scalar parameters. By default, GCC will attempt to pack complex\n\
4778 arguments into the target's word size. Some ABIs require complex arguments\n\
4779 to be split and treated as their individual components. For example, on\n\
4780 AIX64, complex floats should be passed in a pair of floating point\n\
4781 registers, even though a complex float would fit in one 64-bit floating\n\
4782 point register.\n\
4784 The default value of this hook is @code{NULL}, which is treated as always\n\
4785 false.",
4786 bool, (const_tree type), NULL)
4788 /* Return true if type T, mode MODE, may not be passed in registers,
4789 but must be passed on the stack. */
4790 /* ??? This predicate should be applied strictly after pass-by-reference.
4791 Need audit to verify that this is the case. */
4792 DEFHOOK
4793 (must_pass_in_stack,
4794 "This target hook should return @code{true} if we should not pass @var{arg}\n\
4795 solely in registers. The file @file{expr.h} defines a\n\
4796 definition that is usually appropriate, refer to @file{expr.h} for additional\n\
4797 documentation.",
4798 bool, (const function_arg_info &arg),
4799 must_pass_in_stack_var_size_or_pad)
4801 /* Return true if type TYPE, mode MODE, which is passed by reference,
4802 should have the object copy generated by the callee rather than
4803 the caller. It is never called for TYPE requiring constructors. */
4804 DEFHOOK
4805 (callee_copies,
4806 "The function argument described by the parameters to this hook is\n\
4807 known to be passed by reference. The hook should return true if the\n\
4808 function argument should be copied by the callee instead of copied\n\
4809 by the caller.\n\
4811 For any argument for which the hook returns true, if it can be\n\
4812 determined that the argument is not modified, then a copy need\n\
4813 not be generated.\n\
4815 The default version of this hook always returns false.",
4816 bool,
4817 (cumulative_args_t cum, const function_arg_info &arg),
4818 hook_bool_CUMULATIVE_ARGS_arg_info_false)
4820 /* Return zero for arguments passed entirely on the stack or entirely
4821 in registers. If passed in both, return the number of bytes passed
4822 in registers; the balance is therefore passed on the stack. */
4823 DEFHOOK
4824 (arg_partial_bytes,
4825 "This target hook returns the number of bytes at the beginning of an\n\
4826 argument that must be put in registers. The value must be zero for\n\
4827 arguments that are passed entirely in registers or that are entirely\n\
4828 pushed on the stack.\n\
4830 On some machines, certain arguments must be passed partially in\n\
4831 registers and partially in memory. On these machines, typically the\n\
4832 first few words of arguments are passed in registers, and the rest\n\
4833 on the stack. If a multi-word argument (a @code{double} or a\n\
4834 structure) crosses that boundary, its first few words must be passed\n\
4835 in registers and the rest must be pushed. This macro tells the\n\
4836 compiler when this occurs, and how many bytes should go in registers.\n\
4838 @code{TARGET_FUNCTION_ARG} for these arguments should return the first\n\
4839 register to be used by the caller for this argument; likewise\n\
4840 @code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.",
4841 int, (cumulative_args_t cum, const function_arg_info &arg),
4842 hook_int_CUMULATIVE_ARGS_arg_info_0)
4844 /* Update the state in CA to advance past an argument in the
4845 argument list. The values MODE, TYPE, and NAMED describe that
4846 argument. */
4847 DEFHOOK
4848 (function_arg_advance,
4849 "This hook updates the summarizer variable pointed to by @var{ca} to\n\
4850 advance past argument @var{arg} in the argument list. Once this is done,\n\
4851 the variable @var{cum} is suitable for analyzing the @emph{following}\n\
4852 argument with @code{TARGET_FUNCTION_ARG}, etc.\n\
4854 This hook need not do anything if the argument in question was passed\n\
4855 on the stack. The compiler knows how to track the amount of stack space\n\
4856 used for arguments without any special help.",
4857 void,
4858 (cumulative_args_t ca, const function_arg_info &arg),
4859 default_function_arg_advance)
4861 DEFHOOK
4862 (function_arg_offset,
4863 "This hook returns the number of bytes to add to the offset of an\n\
4864 argument of type @var{type} and mode @var{mode} when passed in memory.\n\
4865 This is needed for the SPU, which passes @code{char} and @code{short}\n\
4866 arguments in the preferred slot that is in the middle of the quad word\n\
4867 instead of starting at the top. The default implementation returns 0.",
4868 HOST_WIDE_INT, (machine_mode mode, const_tree type),
4869 default_function_arg_offset)
4871 DEFHOOK
4872 (function_arg_padding,
4873 "This hook determines whether, and in which direction, to pad out\n\
4874 an argument of mode @var{mode} and type @var{type}. It returns\n\
4875 @code{PAD_UPWARD} to insert padding above the argument, @code{PAD_DOWNWARD}\n\
4876 to insert padding below the argument, or @code{PAD_NONE} to inhibit padding.\n\
4878 The @emph{amount} of padding is not controlled by this hook, but by\n\
4879 @code{TARGET_FUNCTION_ARG_ROUND_BOUNDARY}. It is always just enough\n\
4880 to reach the next multiple of that boundary.\n\
4882 This hook has a default definition that is right for most systems.\n\
4883 For little-endian machines, the default is to pad upward. For\n\
4884 big-endian machines, the default is to pad downward for an argument of\n\
4885 constant size shorter than an @code{int}, and upward otherwise.",
4886 pad_direction, (machine_mode mode, const_tree type),
4887 default_function_arg_padding)
4889 /* Return zero if the argument described by the state of CA should
4890 be placed on a stack, or a hard register in which to store the
4891 argument. The values MODE, TYPE, and NAMED describe that
4892 argument. */
4893 DEFHOOK
4894 (function_arg,
4895 "Return an RTX indicating whether function argument @var{arg} is passed\n\
4896 in a register and if so, which register. Argument @var{ca} summarizes all\n\
4897 the previous arguments.\n\
4899 The return value is usually either a @code{reg} RTX for the hard\n\
4900 register in which to pass the argument, or zero to pass the argument\n\
4901 on the stack.\n\
4903 The value of the expression can also be a @code{parallel} RTX@. This is\n\
4904 used when an argument is passed in multiple locations. The mode of the\n\
4905 @code{parallel} should be the mode of the entire argument. The\n\
4906 @code{parallel} holds any number of @code{expr_list} pairs; each one\n\
4907 describes where part of the argument is passed. In each\n\
4908 @code{expr_list} the first operand must be a @code{reg} RTX for the hard\n\
4909 register in which to pass this part of the argument, and the mode of the\n\
4910 register RTX indicates how large this part of the argument is. The\n\
4911 second operand of the @code{expr_list} is a @code{const_int} which gives\n\
4912 the offset in bytes into the entire argument of where this part starts.\n\
4913 As a special exception the first @code{expr_list} in the @code{parallel}\n\
4914 RTX may have a first operand of zero. This indicates that the entire\n\
4915 argument is also stored on the stack.\n\
4917 The last time this hook is called, it is called with @code{MODE ==\n\
4918 VOIDmode}, and its result is passed to the @code{call} or @code{call_value}\n\
4919 pattern as operands 2 and 3 respectively.\n\
4921 @cindex @file{stdarg.h} and register arguments\n\
4922 The usual way to make the ISO library @file{stdarg.h} work on a\n\
4923 machine where some arguments are usually passed in registers, is to\n\
4924 cause nameless arguments to be passed on the stack instead. This is\n\
4925 done by making @code{TARGET_FUNCTION_ARG} return 0 whenever\n\
4926 @var{named} is @code{false}.\n\
4928 @cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}\n\
4929 @cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}\n\
4930 You may use the hook @code{targetm.calls.must_pass_in_stack}\n\
4931 in the definition of this macro to determine if this argument is of a\n\
4932 type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}\n\
4933 is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an\n\
4934 argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is\n\
4935 defined, the argument will be computed in the stack and then loaded into\n\
4936 a register.",
4937 rtx, (cumulative_args_t ca, const function_arg_info &arg),
4938 default_function_arg)
4940 DEFHOOK
4941 (function_incoming_arg,
4942 "Define this hook if the caller and callee on the target have different\n\
4943 views of where arguments are passed. Also define this hook if there are\n\
4944 functions that are never directly called, but are invoked by the hardware\n\
4945 and which have nonstandard calling conventions.\n\
4947 In this case @code{TARGET_FUNCTION_ARG} computes the register in\n\
4948 which the caller passes the value, and\n\
4949 @code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar\n\
4950 fashion to tell the function being called where the arguments will\n\
4951 arrive.\n\
4953 @code{TARGET_FUNCTION_INCOMING_ARG} can also return arbitrary address\n\
4954 computation using hard register, which can be forced into a register,\n\
4955 so that it can be used to pass special arguments.\n\
4957 If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,\n\
4958 @code{TARGET_FUNCTION_ARG} serves both purposes.",
4959 rtx, (cumulative_args_t ca, const function_arg_info &arg),
4960 default_function_incoming_arg)
4962 DEFHOOK
4963 (function_arg_boundary,
4964 "This hook returns the alignment boundary, in bits, of an argument\n\
4965 with the specified mode and type. The default hook returns\n\
4966 @code{PARM_BOUNDARY} for all arguments.",
4967 unsigned int, (machine_mode mode, const_tree type),
4968 default_function_arg_boundary)
4970 DEFHOOK
4971 (function_arg_round_boundary,
4972 "Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
4973 which is the default value for this hook. You can define this hook to\n\
4974 return a different value if an argument size must be rounded to a larger\n\
4975 value.",
4976 unsigned int, (machine_mode mode, const_tree type),
4977 default_function_arg_round_boundary)
4979 /* Return the diagnostic message string if function without a prototype
4980 is not allowed for this 'val' argument; NULL otherwise. */
4981 DEFHOOK
4982 (invalid_arg_for_unprototyped_fn,
4983 "If defined, this macro returns the diagnostic message when it is\n\
4984 illegal to pass argument @var{val} to function @var{funcdecl}\n\
4985 with prototype @var{typelist}.",
4986 const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
4987 hook_invalid_arg_for_unprototyped_fn)
4989 /* Return an rtx for the return value location of the function
4990 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
4991 DEFHOOK
4992 (function_value,
4993 "\n\
4994 Define this to return an RTX representing the place where a function\n\
4995 returns or receives a value of data type @var{ret_type}, a tree node\n\
4996 representing a data type. @var{fn_decl_or_type} is a tree node\n\
4997 representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a\n\
4998 function being called. If @var{outgoing} is false, the hook should\n\
4999 compute the register in which the caller will see the return value.\n\
5000 Otherwise, the hook should return an RTX representing the place where\n\
5001 a function returns a value.\n\
5003 On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.\n\
5004 (Actually, on most machines, scalar values are returned in the same\n\
5005 place regardless of mode.) The value of the expression is usually a\n\
5006 @code{reg} RTX for the hard register where the return value is stored.\n\
5007 The value can also be a @code{parallel} RTX, if the return value is in\n\
5008 multiple places. See @code{TARGET_FUNCTION_ARG} for an explanation of the\n\
5009 @code{parallel} form. Note that the callee will populate every\n\
5010 location specified in the @code{parallel}, but if the first element of\n\
5011 the @code{parallel} contains the whole return value, callers will use\n\
5012 that element as the canonical location and ignore the others. The m68k\n\
5013 port uses this type of @code{parallel} to return pointers in both\n\
5014 @samp{%a0} (the canonical location) and @samp{%d0}.\n\
5016 If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply\n\
5017 the same promotion rules specified in @code{PROMOTE_MODE} if\n\
5018 @var{valtype} is a scalar type.\n\
5020 If the precise function being called is known, @var{func} is a tree\n\
5021 node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null\n\
5022 pointer. This makes it possible to use a different value-returning\n\
5023 convention for specific functions when all their calls are\n\
5024 known.\n\
5026 Some target machines have ``register windows'' so that the register in\n\
5027 which a function returns its value is not the same as the one in which\n\
5028 the caller sees the value. For such machines, you should return\n\
5029 different RTX depending on @var{outgoing}.\n\
5031 @code{TARGET_FUNCTION_VALUE} is not used for return values with\n\
5032 aggregate data types, because these are returned in another way. See\n\
5033 @code{TARGET_STRUCT_VALUE_RTX} and related macros, below.",
5034 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
5035 default_function_value)
5037 /* Return the rtx for the result of a libcall of mode MODE,
5038 calling the function FN_NAME. */
5039 DEFHOOK
5040 (libcall_value,
5041 "Define this hook if the back-end needs to know the name of the libcall\n\
5042 function in order to determine where the result should be returned.\n\
5044 The mode of the result is given by @var{mode} and the name of the called\n\
5045 library function is given by @var{fun}. The hook should return an RTX\n\
5046 representing the place where the library function result will be returned.\n\
5048 If this hook is not defined, then LIBCALL_VALUE will be used.",
5049 rtx, (machine_mode mode, const_rtx fun),
5050 default_libcall_value)
5052 /* Return true if REGNO is a possible register number for
5053 a function value as seen by the caller. */
5054 DEFHOOK
5055 (function_value_regno_p,
5056 "A target hook that return @code{true} if @var{regno} is the number of a hard\n\
5057 register in which the values of called function may come back.\n\
5059 A register whose use for returning values is limited to serving as the\n\
5060 second of a pair (for a value of type @code{double}, say) need not be\n\
5061 recognized by this target hook.\n\
5063 If the machine has register windows, so that the caller and the called\n\
5064 function use different registers for the return value, this target hook\n\
5065 should recognize only the caller's register numbers.\n\
5067 If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.",
5068 bool, (const unsigned int regno),
5069 default_function_value_regno_p)
5071 DEFHOOK
5072 (fntype_abi,
5073 "Return the ABI used by a function with type @var{type}; see the\n\
5074 definition of @code{predefined_function_abi} for details of the ABI\n\
5075 descriptor. Targets only need to define this hook if they support\n\
5076 interoperability between several ABIs in the same translation unit.",
5077 const predefined_function_abi &, (const_tree type),
5078 NULL)
5080 DEFHOOK
5081 (insn_callee_abi,
5082 "This hook returns a description of the ABI used by the target of\n\
5083 call instruction @var{insn}; see the definition of\n\
5084 @code{predefined_function_abi} for details of the ABI descriptor.\n\
5085 Only the global function @code{insn_callee_abi} should call this hook\n\
5086 directly.\n\
5088 Targets only need to define this hook if they support\n\
5089 interoperability between several ABIs in the same translation unit.",
5090 const predefined_function_abi &, (const rtx_insn *insn),
5091 NULL)
5093 /* ??? Documenting this hook requires a GFDL license grant. */
5094 DEFHOOK_UNDOC
5095 (internal_arg_pointer,
5096 "Return an rtx for the argument pointer incoming to the\
5097 current function.",
5098 rtx, (void),
5099 default_internal_arg_pointer)
5101 /* Update the current function stack boundary if needed. */
5102 DEFHOOK
5103 (update_stack_boundary,
5104 "Define this macro to update the current function stack boundary if\n\
5105 necessary.",
5106 void, (void), NULL)
5108 /* Handle stack alignment and return an rtx for Dynamic Realign
5109 Argument Pointer if necessary. */
5110 DEFHOOK
5111 (get_drap_rtx,
5112 "This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a\n\
5113 different argument pointer register is needed to access the function's\n\
5114 argument list due to stack realignment. Return @code{NULL} if no DRAP\n\
5115 is needed.",
5116 rtx, (void), NULL)
5118 /* Generate instruction sequence to zero call used registers. */
5119 DEFHOOK
5120 (zero_call_used_regs,
5121 "This target hook emits instructions to zero the subset of @var{selected_regs}\n\
5122 that could conceivably contain values that are useful to an attacker.\n\
5123 Return the set of registers that were actually cleared.\n\
5125 For most targets, the returned set of registers is a subset of\n\
5126 @var{selected_regs}, however, for some of the targets (for example MIPS),\n\
5127 clearing some registers that are in the @var{selected_regs} requires\n\
5128 clearing other call used registers that are not in the @var{selected_regs},\n\
5129 under such situation, the returned set of registers must be a subset of all\n\
5130 call used registers.\n\
5132 The default implementation uses normal move instructions to zero\n\
5133 all the registers in @var{selected_regs}. Define this hook if the\n\
5134 target has more efficient ways of zeroing certain registers,\n\
5135 or if you believe that certain registers would never contain\n\
5136 values that are useful to an attacker.",
5137 HARD_REG_SET, (HARD_REG_SET selected_regs),
5138 default_zero_call_used_regs)
5140 /* Return true if all function parameters should be spilled to the
5141 stack. */
5142 DEFHOOK
5143 (allocate_stack_slots_for_args,
5144 "When optimization is disabled, this hook indicates whether or not\n\
5145 arguments should be allocated to stack slots. Normally, GCC allocates\n\
5146 stacks slots for arguments when not optimizing in order to make\n\
5147 debugging easier. However, when a function is declared with\n\
5148 @code{__attribute__((naked))}, there is no stack frame, and the compiler\n\
5149 cannot safely move arguments from the registers in which they are passed\n\
5150 to the stack. Therefore, this hook should return true in general, but\n\
5151 false for naked functions. The default implementation always returns true.",
5152 bool, (void),
5153 hook_bool_void_true)
5155 /* Return an rtx for the static chain for FNDECL_OR_TYPE. If INCOMING_P
5156 is true, then it should be for the callee; otherwise for the caller. */
5157 DEFHOOK
5158 (static_chain,
5159 "This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for\n\
5160 targets that may use different static chain locations for different\n\
5161 nested functions. This may be required if the target has function\n\
5162 attributes that affect the calling conventions of the function and\n\
5163 those calling conventions use different static chain locations.\n\
5165 The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.\n\
5167 If the static chain is passed in memory, this hook should be used to\n\
5168 provide rtx giving @code{mem} expressions that denote where they are stored.\n\
5169 Often the @code{mem} expression as seen by the caller will be at an offset\n\
5170 from the stack pointer and the @code{mem} expression as seen by the callee\n\
5171 will be at an offset from the frame pointer.\n\
5172 @findex stack_pointer_rtx\n\
5173 @findex frame_pointer_rtx\n\
5174 @findex arg_pointer_rtx\n\
5175 The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and\n\
5176 @code{arg_pointer_rtx} will have been initialized and should be used\n\
5177 to refer to those items.",
5178 rtx, (const_tree fndecl_or_type, bool incoming_p),
5179 default_static_chain)
5181 /* Fill in the trampoline at MEM with a call to FNDECL and a
5182 static chain value of CHAIN. */
5183 DEFHOOK
5184 (trampoline_init,
5185 "This hook is called to initialize a trampoline.\n\
5186 @var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}\n\
5187 is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an\n\
5188 RTX for the static chain value that should be passed to the function\n\
5189 when it is called.\n\
5191 If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the\n\
5192 first thing this hook should do is emit a block move into @var{m_tramp}\n\
5193 from the memory block returned by @code{assemble_trampoline_template}.\n\
5194 Note that the block move need only cover the constant parts of the\n\
5195 trampoline. If the target isolates the variable parts of the trampoline\n\
5196 to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.\n\
5198 If the target requires any other actions, such as flushing caches\n\
5199 (possibly calling function maybe_emit_call_builtin___clear_cache) or\n\
5200 enabling stack execution, these actions should be performed after\n\
5201 initializing the trampoline proper.",
5202 void, (rtx m_tramp, tree fndecl, rtx static_chain),
5203 default_trampoline_init)
5205 /* Emit a call to a function to clear the instruction cache. */
5206 DEFHOOK
5207 (emit_call_builtin___clear_cache,
5208 "On targets that do not define a @code{clear_cache} insn expander,\n\
5209 but that define the @code{CLEAR_CACHE_INSN} macro,\n\
5210 maybe_emit_call_builtin___clear_cache relies on this target hook\n\
5211 to clear an address range in the instruction cache.\n\
5213 The default implementation calls the @code{__clear_cache} builtin,\n\
5214 taking the assembler name from the builtin declaration. Overriding\n\
5215 definitions may call alternate functions, with alternate calling\n\
5216 conventions, or emit alternate RTX to perform the job.",
5217 void, (rtx begin, rtx end),
5218 default_emit_call_builtin___clear_cache)
5220 /* Adjust the address of the trampoline in a target-specific way. */
5221 DEFHOOK
5222 (trampoline_adjust_address,
5223 "This hook should perform any machine-specific adjustment in\n\
5224 the address of the trampoline. Its argument contains the address of the\n\
5225 memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}. In case\n\
5226 the address to be used for a function call should be different from the\n\
5227 address at which the template was stored, the different address should\n\
5228 be returned; otherwise @var{addr} should be returned unchanged.\n\
5229 If this hook is not defined, @var{addr} will be used for function calls.",
5230 rtx, (rtx addr), NULL)
5232 DEFHOOKPOD
5233 (custom_function_descriptors,
5234 "If the target can use GCC's generic descriptor mechanism for nested\n\
5235 functions, define this hook to a power of 2 representing an unused bit\n\
5236 in function pointers which can be used to differentiate descriptors at\n\
5237 run time. This value gives the number of bytes by which descriptor\n\
5238 pointers are misaligned compared to function pointers. For example, on\n\
5239 targets that require functions to be aligned to a 4-byte boundary, a\n\
5240 value of either 1 or 2 is appropriate unless the architecture already\n\
5241 reserves the bit for another purpose, such as on ARM.\n\
5243 Define this hook to 0 if the target implements ABI support for\n\
5244 function descriptors in its standard calling sequence, like for example\n\
5245 HPPA or IA-64.\n\
5247 Using descriptors for nested functions\n\
5248 eliminates the need for trampolines that reside on the stack and require\n\
5249 it to be made executable.",
5250 int, -1)
5252 /* Return the number of bytes of its own arguments that a function
5253 pops on returning, or 0 if the function pops no arguments and the
5254 caller must therefore pop them all after the function returns. */
5255 /* ??? tm.texi has no types for the parameters. */
5256 DEFHOOK
5257 (return_pops_args,
5258 "This target hook returns the number of bytes of its own arguments that\n\
5259 a function pops on returning, or 0 if the function pops no arguments\n\
5260 and the caller must therefore pop them all after the function returns.\n\
5262 @var{fundecl} is a C variable whose value is a tree node that describes\n\
5263 the function in question. Normally it is a node of type\n\
5264 @code{FUNCTION_DECL} that describes the declaration of the function.\n\
5265 From this you can obtain the @code{DECL_ATTRIBUTES} of the function.\n\
5267 @var{funtype} is a C variable whose value is a tree node that\n\
5268 describes the function in question. Normally it is a node of type\n\
5269 @code{FUNCTION_TYPE} that describes the data type of the function.\n\
5270 From this it is possible to obtain the data types of the value and\n\
5271 arguments (if known).\n\
5273 When a call to a library function is being considered, @var{fundecl}\n\
5274 will contain an identifier node for the library function. Thus, if\n\
5275 you need to distinguish among various library functions, you can do so\n\
5276 by their names. Note that ``library function'' in this context means\n\
5277 a function used to perform arithmetic, whose name is known specially\n\
5278 in the compiler and was not mentioned in the C code being compiled.\n\
5280 @var{size} is the number of bytes of arguments passed on the\n\
5281 stack. If a variable number of bytes is passed, it is zero, and\n\
5282 argument popping will always be the responsibility of the calling function.\n\
5284 On the VAX, all functions always pop their arguments, so the definition\n\
5285 of this macro is @var{size}. On the 68000, using the standard\n\
5286 calling convention, no functions pop their arguments, so the value of\n\
5287 the macro is always 0 in this case. But an alternative calling\n\
5288 convention is available in which functions that take a fixed number of\n\
5289 arguments pop them but other functions (such as @code{printf}) pop\n\
5290 nothing (the caller pops all). When this convention is in use,\n\
5291 @var{funtype} is examined to determine whether a function takes a fixed\n\
5292 number of arguments.",
5293 poly_int64, (tree fundecl, tree funtype, poly_int64 size),
5294 default_return_pops_args)
5296 /* Return a mode wide enough to copy any function value that might be
5297 returned. */
5298 DEFHOOK
5299 (get_raw_result_mode,
5300 "This target hook returns the mode to be used when accessing raw return\n\
5301 registers in @code{__builtin_return}. Define this macro if the value\n\
5302 in @var{reg_raw_mode} is not correct.",
5303 fixed_size_mode, (int regno),
5304 default_get_reg_raw_mode)
5306 /* Return a mode wide enough to copy any argument value that might be
5307 passed. */
5308 DEFHOOK
5309 (get_raw_arg_mode,
5310 "This target hook returns the mode to be used when accessing raw argument\n\
5311 registers in @code{__builtin_apply_args}. Define this macro if the value\n\
5312 in @var{reg_raw_mode} is not correct.",
5313 fixed_size_mode, (int regno),
5314 default_get_reg_raw_mode)
5316 /* Return true if a type is an empty record. */
5317 DEFHOOK
5318 (empty_record_p,
5319 "This target hook returns true if the type is an empty record. The default\n\
5320 is to return @code{false}.",
5321 bool, (const_tree type),
5322 hook_bool_const_tree_false)
5324 /* Warn about the change in empty class parameter passing ABI. */
5325 DEFHOOK
5326 (warn_parameter_passing_abi,
5327 "This target hook warns about the change in empty class parameter passing\n\
5328 ABI.",
5329 void, (cumulative_args_t ca, tree type),
5330 hook_void_CUMULATIVE_ARGS_tree)
5332 HOOK_VECTOR_END (calls)
5334 DEFHOOK
5335 (use_pseudo_pic_reg,
5336 "This hook should return 1 in case pseudo register should be created\n\
5337 for pic_offset_table_rtx during function expand.",
5338 bool, (void),
5339 hook_bool_void_false)
5341 DEFHOOK
5342 (init_pic_reg,
5343 "Perform a target dependent initialization of pic_offset_table_rtx.\n\
5344 This hook is called at the start of register allocation.",
5345 void, (void),
5346 hook_void_void)
5348 /* Return the diagnostic message string if conversion from FROMTYPE
5349 to TOTYPE is not allowed, NULL otherwise. */
5350 DEFHOOK
5351 (invalid_conversion,
5352 "If defined, this macro returns the diagnostic message when it is\n\
5353 invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}\n\
5354 if validity should be determined by the front end.",
5355 const char *, (const_tree fromtype, const_tree totype),
5356 hook_constcharptr_const_tree_const_tree_null)
5358 /* Return the diagnostic message string if the unary operation OP is
5359 not permitted on TYPE, NULL otherwise. */
5360 DEFHOOK
5361 (invalid_unary_op,
5362 "If defined, this macro returns the diagnostic message when it is\n\
5363 invalid to apply operation @var{op} (where unary plus is denoted by\n\
5364 @code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}\n\
5365 if validity should be determined by the front end.",
5366 const char *, (int op, const_tree type),
5367 hook_constcharptr_int_const_tree_null)
5369 /* Return the diagnostic message string if the binary operation OP
5370 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
5371 DEFHOOK
5372 (invalid_binary_op,
5373 "If defined, this macro returns the diagnostic message when it is\n\
5374 invalid to apply operation @var{op} to operands of types @var{type1}\n\
5375 and @var{type2}, or @code{NULL} if validity should be determined by\n\
5376 the front end.",
5377 const char *, (int op, const_tree type1, const_tree type2),
5378 hook_constcharptr_int_const_tree_const_tree_null)
5380 /* If values of TYPE are promoted to some other type when used in
5381 expressions (analogous to the integer promotions), return that type,
5382 or NULL_TREE otherwise. */
5383 DEFHOOK
5384 (promoted_type,
5385 "If defined, this target hook returns the type to which values of\n\
5386 @var{type} should be promoted when they appear in expressions,\n\
5387 analogous to the integer promotions, or @code{NULL_TREE} to use the\n\
5388 front end's normal promotion rules. This hook is useful when there are\n\
5389 target-specific types with special promotion rules.\n\
5390 This is currently used only by the C and C++ front ends.",
5391 tree, (const_tree type),
5392 hook_tree_const_tree_null)
5394 /* Convert EXPR to TYPE, if target-specific types with special conversion
5395 rules are involved. Return the converted expression, or NULL to apply
5396 the standard conversion rules. */
5397 DEFHOOK
5398 (convert_to_type,
5399 "If defined, this hook returns the result of converting @var{expr} to\n\
5400 @var{type}. It should return the converted expression,\n\
5401 or @code{NULL_TREE} to apply the front end's normal conversion rules.\n\
5402 This hook is useful when there are target-specific types with special\n\
5403 conversion rules.\n\
5404 This is currently used only by the C and C++ front ends.",
5405 tree, (tree type, tree expr),
5406 hook_tree_tree_tree_null)
5408 DEFHOOK
5409 (verify_type_context,
5410 "If defined, this hook returns false if there is a target-specific reason\n\
5411 why type @var{type} cannot be used in the source language context described\n\
5412 by @var{context}. When @var{silent_p} is false, the hook also reports an\n\
5413 error against @var{loc} for invalid uses of @var{type}.\n\
5415 Calls to this hook should be made through the global function\n\
5416 @code{verify_type_context}, which makes the @var{silent_p} parameter\n\
5417 default to false and also handles @code{error_mark_node}.\n\
5419 The default implementation always returns true.",
5420 bool, (location_t loc, type_context_kind context, const_tree type,
5421 bool silent_p),
5422 NULL)
5424 DEFHOOK
5425 (can_change_mode_class,
5426 "This hook returns true if it is possible to bitcast values held in\n\
5427 registers of class @var{rclass} from mode @var{from} to mode @var{to}\n\
5428 and if doing so preserves the low-order bits that are common to both modes.\n\
5429 The result is only meaningful if @var{rclass} has registers that can hold\n\
5430 both @code{from} and @code{to}. The default implementation returns true.\n\
5432 As an example of when such bitcasting is invalid, loading 32-bit integer or\n\
5433 floating-point objects into floating-point registers on Alpha extends them\n\
5434 to 64 bits. Therefore loading a 64-bit object and then storing it as a\n\
5435 32-bit object does not store the low-order 32 bits, as would be the case\n\
5436 for a normal register. Therefore, @file{alpha.h} defines\n\
5437 @code{TARGET_CAN_CHANGE_MODE_CLASS} to return:\n\
5439 @smallexample\n\
5440 (GET_MODE_SIZE (from) == GET_MODE_SIZE (to)\n\
5441 || !reg_classes_intersect_p (FLOAT_REGS, rclass))\n\
5442 @end smallexample\n\
5444 Even if storing from a register in mode @var{to} would be valid,\n\
5445 if both @var{from} and @code{raw_reg_mode} for @var{rclass} are wider\n\
5446 than @code{word_mode}, then we must prevent @var{to} narrowing the\n\
5447 mode. This happens when the middle-end assumes that it can load\n\
5448 or store pieces of an @var{N}-word pseudo, and that the pseudo will\n\
5449 eventually be allocated to @var{N} @code{word_mode} hard registers.\n\
5450 Failure to prevent this kind of mode change will result in the\n\
5451 entire @code{raw_reg_mode} being modified instead of the partial\n\
5452 value that the middle-end intended.",
5453 bool, (machine_mode from, machine_mode to, reg_class_t rclass),
5454 hook_bool_mode_mode_reg_class_t_true)
5456 /* Change pseudo allocno class calculated by IRA. */
5457 DEFHOOK
5458 (ira_change_pseudo_allocno_class,
5459 "A target hook which can change allocno class for given pseudo from\n\
5460 allocno and best class calculated by IRA.\n\
5462 The default version of this target hook always returns given class.",
5463 reg_class_t, (int, reg_class_t, reg_class_t),
5464 default_ira_change_pseudo_allocno_class)
5466 /* Return true if we use LRA instead of reload. */
5467 DEFHOOK
5468 (lra_p,
5469 "A target hook which returns true if we use LRA instead of reload pass.\n\
5471 The default version of this target hook returns true. New ports\n\
5472 should use LRA, and existing ports are encouraged to convert.",
5473 bool, (void),
5474 default_lra_p)
5476 /* Return register priority of given hard regno for the current target. */
5477 DEFHOOK
5478 (register_priority,
5479 "A target hook which returns the register priority number to which the\n\
5480 register @var{hard_regno} belongs to. The bigger the number, the\n\
5481 more preferable the hard register usage (when all other conditions are\n\
5482 the same). This hook can be used to prefer some hard register over\n\
5483 others in LRA. For example, some x86-64 register usage needs\n\
5484 additional prefix which makes instructions longer. The hook can\n\
5485 return lower priority number for such registers make them less favorable\n\
5486 and as result making the generated code smaller.\n\
5488 The default version of this target hook returns always zero.",
5489 int, (int),
5490 default_register_priority)
5492 /* Return true if we need register usage leveling. */
5493 DEFHOOK
5494 (register_usage_leveling_p,
5495 "A target hook which returns true if we need register usage leveling.\n\
5496 That means if a few hard registers are equally good for the\n\
5497 assignment, we choose the least used hard register. The register\n\
5498 usage leveling may be profitable for some targets. Don't use the\n\
5499 usage leveling for targets with conditional execution or targets\n\
5500 with big register files as it hurts if-conversion and cross-jumping\n\
5501 optimizations.\n\
5503 The default version of this target hook returns always false.",
5504 bool, (void),
5505 default_register_usage_leveling_p)
5507 /* Return true if maximal address displacement can be different. */
5508 DEFHOOK
5509 (different_addr_displacement_p,
5510 "A target hook which returns true if an address with the same structure\n\
5511 can have different maximal legitimate displacement. For example, the\n\
5512 displacement can depend on memory mode or on operand combinations in\n\
5513 the insn.\n\
5515 The default version of this target hook returns always false.",
5516 bool, (void),
5517 default_different_addr_displacement_p)
5519 /* Determine class for spilling pseudos of given mode into registers
5520 instead of memory. */
5521 DEFHOOK
5522 (spill_class,
5523 "This hook defines a class of registers which could be used for spilling\n\
5524 pseudos of the given mode and class, or @code{NO_REGS} if only memory\n\
5525 should be used. Not defining this hook is equivalent to returning\n\
5526 @code{NO_REGS} for all inputs.",
5527 reg_class_t, (reg_class_t, machine_mode),
5528 NULL)
5530 /* Determine an additional allocno class. */
5531 DEFHOOK
5532 (additional_allocno_class_p,
5533 "This hook should return @code{true} if given class of registers should\n\
5534 be an allocno class in any way. Usually RA uses only one register\n\
5535 class from all classes containing the same register set. In some\n\
5536 complicated cases, you need to have two or more such classes as\n\
5537 allocno ones for RA correct work. Not defining this hook is\n\
5538 equivalent to returning @code{false} for all inputs.",
5539 bool, (reg_class_t),
5540 hook_bool_reg_class_t_false)
5542 DEFHOOK
5543 (cstore_mode,
5544 "This hook defines the machine mode to use for the boolean result of\n\
5545 conditional store patterns. The ICODE argument is the instruction code\n\
5546 for the cstore being performed. Not definiting this hook is the same\n\
5547 as accepting the mode encoded into operand 0 of the cstore expander\n\
5548 patterns.",
5549 scalar_int_mode, (enum insn_code icode),
5550 default_cstore_mode)
5552 /* This target hook allows the backend to compute the register pressure
5553 classes to use. */
5554 DEFHOOK
5555 (compute_pressure_classes,
5556 "A target hook which lets a backend compute the set of pressure classes to\n\
5557 be used by those optimization passes which take register pressure into\n\
5558 account, as opposed to letting IRA compute them. It returns the number of\n\
5559 register classes stored in the array @var{pressure_classes}.",
5560 int, (enum reg_class *pressure_classes), NULL)
5562 /* True if a structure, union or array with MODE containing FIELD should
5563 be accessed using BLKmode. */
5564 DEFHOOK
5565 (member_type_forces_blk,
5566 "Return true if a structure, union or array containing @var{field} should\n\
5567 be accessed using @code{BLKMODE}.\n\
5569 If @var{field} is the only field in the structure, @var{mode} is its\n\
5570 mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the\n\
5571 case where structures of one field would require the structure's mode to\n\
5572 retain the field's mode.\n\
5574 Normally, this is not needed.",
5575 bool, (const_tree field, machine_mode mode),
5576 default_member_type_forces_blk)
5578 /* See tree-ssa-math-opts.cc:divmod_candidate_p for conditions
5579 that gate the divod transform. */
5580 DEFHOOK
5581 (expand_divmod_libfunc,
5582 "Define this hook for enabling divmod transform if the port does not have\n\
5583 hardware divmod insn but defines target-specific divmod libfuncs.",
5584 void, (rtx libfunc, machine_mode mode, rtx op0, rtx op1, rtx *quot, rtx *rem),
5585 NULL)
5587 /* Return the class for a secondary reload, and fill in extra information. */
5588 DEFHOOK
5589 (secondary_reload,
5590 "Many machines have some registers that cannot be copied directly to or\n\
5591 from memory or even from other types of registers. An example is the\n\
5592 @samp{MQ} register, which on most machines, can only be copied to or\n\
5593 from general registers, but not memory. Below, we shall be using the\n\
5594 term 'intermediate register' when a move operation cannot be performed\n\
5595 directly, but has to be done by copying the source into the intermediate\n\
5596 register first, and then copying the intermediate register to the\n\
5597 destination. An intermediate register always has the same mode as\n\
5598 source and destination. Since it holds the actual value being copied,\n\
5599 reload might apply optimizations to re-use an intermediate register\n\
5600 and eliding the copy from the source when it can determine that the\n\
5601 intermediate register still holds the required value.\n\
5603 Another kind of secondary reload is required on some machines which\n\
5604 allow copying all registers to and from memory, but require a scratch\n\
5605 register for stores to some memory locations (e.g., those with symbolic\n\
5606 address on the RT, and those with certain symbolic address on the SPARC\n\
5607 when compiling PIC)@. Scratch registers need not have the same mode\n\
5608 as the value being copied, and usually hold a different value than\n\
5609 that being copied. Special patterns in the md file are needed to\n\
5610 describe how the copy is performed with the help of the scratch register;\n\
5611 these patterns also describe the number, register class(es) and mode(s)\n\
5612 of the scratch register(s).\n\
5614 In some cases, both an intermediate and a scratch register are required.\n\
5616 For input reloads, this target hook is called with nonzero @var{in_p},\n\
5617 and @var{x} is an rtx that needs to be copied to a register of class\n\
5618 @var{reload_class} in @var{reload_mode}. For output reloads, this target\n\
5619 hook is called with zero @var{in_p}, and a register of class @var{reload_class}\n\
5620 needs to be copied to rtx @var{x} in @var{reload_mode}.\n\
5622 If copying a register of @var{reload_class} from/to @var{x} requires\n\
5623 an intermediate register, the hook @code{secondary_reload} should\n\
5624 return the register class required for this intermediate register.\n\
5625 If no intermediate register is required, it should return NO_REGS.\n\
5626 If more than one intermediate register is required, describe the one\n\
5627 that is closest in the copy chain to the reload register.\n\
5629 If scratch registers are needed, you also have to describe how to\n\
5630 perform the copy from/to the reload register to/from this\n\
5631 closest intermediate register. Or if no intermediate register is\n\
5632 required, but still a scratch register is needed, describe the\n\
5633 copy from/to the reload register to/from the reload operand @var{x}.\n\
5635 You do this by setting @code{sri->icode} to the instruction code of a pattern\n\
5636 in the md file which performs the move. Operands 0 and 1 are the output\n\
5637 and input of this copy, respectively. Operands from operand 2 onward are\n\
5638 for scratch operands. These scratch operands must have a mode, and a\n\
5639 single-register-class\n\
5640 @c [later: or memory]\n\
5641 output constraint.\n\
5643 When an intermediate register is used, the @code{secondary_reload}\n\
5644 hook will be called again to determine how to copy the intermediate\n\
5645 register to/from the reload operand @var{x}, so your hook must also\n\
5646 have code to handle the register class of the intermediate operand.\n\
5648 @c [For later: maybe we'll allow multi-alternative reload patterns -\n\
5649 @c the port maintainer could name a mov<mode> pattern that has clobbers -\n\
5650 @c and match the constraints of input and output to determine the required\n\
5651 @c alternative. A restriction would be that constraints used to match\n\
5652 @c against reloads registers would have to be written as register class\n\
5653 @c constraints, or we need a new target macro / hook that tells us if an\n\
5654 @c arbitrary constraint can match an unknown register of a given class.\n\
5655 @c Such a macro / hook would also be useful in other places.]\n\
5658 @var{x} might be a pseudo-register or a @code{subreg} of a\n\
5659 pseudo-register, which could either be in a hard register or in memory.\n\
5660 Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is\n\
5661 in memory and the hard register number if it is in a register.\n\
5663 Scratch operands in memory (constraint @code{\"=m\"} / @code{\"=&m\"}) are\n\
5664 currently not supported. For the time being, you will have to continue\n\
5665 to use @code{TARGET_SECONDARY_MEMORY_NEEDED} for that purpose.\n\
5667 @code{copy_cost} also uses this target hook to find out how values are\n\
5668 copied. If you want it to include some extra cost for the need to allocate\n\
5669 (a) scratch register(s), set @code{sri->extra_cost} to the additional cost.\n\
5670 Or if two dependent moves are supposed to have a lower cost than the sum\n\
5671 of the individual moves due to expected fortuitous scheduling and/or special\n\
5672 forwarding logic, you can set @code{sri->extra_cost} to a negative amount.",
5673 reg_class_t,
5674 (bool in_p, rtx x, reg_class_t reload_class, machine_mode reload_mode,
5675 secondary_reload_info *sri),
5676 default_secondary_reload)
5678 DEFHOOK
5679 (secondary_memory_needed,
5680 "Certain machines have the property that some registers cannot be copied\n\
5681 to some other registers without using memory. Define this hook on\n\
5682 those machines to return true if objects of mode @var{m} in registers\n\
5683 of @var{class1} can only be copied to registers of class @var{class2} by\n\
5684 storing a register of @var{class1} into memory and loading that memory\n\
5685 location into a register of @var{class2}. The default definition returns\n\
5686 false for all inputs.",
5687 bool, (machine_mode mode, reg_class_t class1, reg_class_t class2),
5688 hook_bool_mode_reg_class_t_reg_class_t_false)
5690 DEFHOOK
5691 (secondary_memory_needed_mode,
5692 "If @code{TARGET_SECONDARY_MEMORY_NEEDED} tells the compiler to use memory\n\
5693 when moving between two particular registers of mode @var{mode},\n\
5694 this hook specifies the mode that the memory should have.\n\
5696 The default depends on @code{TARGET_LRA_P}. Without LRA, the default\n\
5697 is to use a word-sized mode for integral modes that are smaller than a\n\
5698 a word. This is right thing to do on most machines because it ensures\n\
5699 that all bits of the register are copied and prevents accesses to the\n\
5700 registers in a narrower mode, which some machines prohibit for\n\
5701 floating-point registers.\n\
5703 However, this default behavior is not correct on some machines, such as\n\
5704 the DEC Alpha, that store short integers in floating-point registers\n\
5705 differently than in integer registers. On those machines, the default\n\
5706 widening will not work correctly and you must define this hook to\n\
5707 suppress that widening in some cases. See the file @file{alpha.cc} for\n\
5708 details.\n\
5710 With LRA, the default is to use @var{mode} unmodified.",
5711 machine_mode, (machine_mode mode),
5712 default_secondary_memory_needed_mode)
5714 /* Given an rtx X being reloaded into a reg required to be in class CLASS,
5715 return the class of reg to actually use. */
5716 DEFHOOK
5717 (preferred_reload_class,
5718 "A target hook that places additional restrictions on the register class\n\
5719 to use when it is necessary to copy value @var{x} into a register in class\n\
5720 @var{rclass}. The value is a register class; perhaps @var{rclass}, or perhaps\n\
5721 another, smaller class.\n\
5723 The default version of this hook always returns value of @code{rclass} argument.\n\
5725 Sometimes returning a more restrictive class makes better code. For\n\
5726 example, on the 68000, when @var{x} is an integer constant that is in range\n\
5727 for a @samp{moveq} instruction, the value of this macro is always\n\
5728 @code{DATA_REGS} as long as @var{rclass} includes the data registers.\n\
5729 Requiring a data register guarantees that a @samp{moveq} will be used.\n\
5731 One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return\n\
5732 @var{rclass} is if @var{x} is a legitimate constant which cannot be\n\
5733 loaded into some register class. By returning @code{NO_REGS} you can\n\
5734 force @var{x} into a memory location. For example, rs6000 can load\n\
5735 immediate values into general-purpose registers, but does not have an\n\
5736 instruction for loading an immediate value into a floating-point\n\
5737 register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when\n\
5738 @var{x} is a floating-point constant. If the constant can't be loaded\n\
5739 into any kind of register, code generation will be better if\n\
5740 @code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead\n\
5741 of using @code{TARGET_PREFERRED_RELOAD_CLASS}.\n\
5743 If an insn has pseudos in it after register allocation, reload will go\n\
5744 through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}\n\
5745 to find the best one. Returning @code{NO_REGS}, in this case, makes\n\
5746 reload add a @code{!} in front of the constraint: the x86 back-end uses\n\
5747 this feature to discourage usage of 387 registers when math is done in\n\
5748 the SSE registers (and vice versa).",
5749 reg_class_t,
5750 (rtx x, reg_class_t rclass),
5751 default_preferred_reload_class)
5753 /* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
5754 input reloads. */
5755 DEFHOOK
5756 (preferred_output_reload_class,
5757 "Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of\n\
5758 input reloads.\n\
5760 The default version of this hook always returns value of @code{rclass}\n\
5761 argument.\n\
5763 You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage\n\
5764 reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.",
5765 reg_class_t,
5766 (rtx x, reg_class_t rclass),
5767 default_preferred_output_reload_class)
5769 DEFHOOK
5770 (select_early_remat_modes,
5771 "On some targets, certain modes cannot be held in registers around a\n\
5772 standard ABI call and are relatively expensive to spill to the stack.\n\
5773 The early rematerialization pass can help in such cases by aggressively\n\
5774 recomputing values after calls, so that they don't need to be spilled.\n\
5776 This hook returns the set of such modes by setting the associated bits\n\
5777 in @var{modes}. The default implementation selects no modes, which has\n\
5778 the effect of disabling the early rematerialization pass.",
5779 void, (sbitmap modes),
5780 default_select_early_remat_modes)
5782 DEFHOOK
5783 (class_likely_spilled_p,
5784 "A target hook which returns @code{true} if pseudos that have been assigned\n\
5785 to registers of class @var{rclass} would likely be spilled because\n\
5786 registers of @var{rclass} are needed for spill registers.\n\
5788 The default version of this target hook returns @code{true} if @var{rclass}\n\
5789 has exactly one register and @code{false} otherwise. On most machines, this\n\
5790 default should be used. For generally register-starved machines, such as\n\
5791 i386, or machines with right register constraints, such as SH, this hook\n\
5792 can be used to avoid excessive spilling.\n\
5794 This hook is also used by some of the global intra-procedural code\n\
5795 transformations to throtle code motion, to avoid increasing register\n\
5796 pressure.",
5797 bool, (reg_class_t rclass),
5798 default_class_likely_spilled_p)
5800 /* Return the maximum number of consecutive registers
5801 needed to represent mode MODE in a register of class RCLASS. */
5802 DEFHOOK
5803 (class_max_nregs,
5804 "A target hook returns the maximum number of consecutive registers\n\
5805 of class @var{rclass} needed to hold a value of mode @var{mode}.\n\
5807 This is closely related to the macro @code{TARGET_HARD_REGNO_NREGS}.\n\
5808 In fact, the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},\n\
5809 @var{mode})} target hook should be the maximum value of\n\
5810 @code{TARGET_HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}\n\
5811 values in the class @var{rclass}.\n\
5813 This target hook helps control the handling of multiple-word values\n\
5814 in the reload pass.\n\
5816 The default version of this target hook returns the size of @var{mode}\n\
5817 in words.",
5818 unsigned char, (reg_class_t rclass, machine_mode mode),
5819 default_class_max_nregs)
5821 DEFHOOK
5822 (preferred_rename_class,
5823 "A target hook that places additional preference on the register\n\
5824 class to use when it is necessary to rename a register in class\n\
5825 @var{rclass} to another class, or perhaps @var{NO_REGS}, if no\n\
5826 preferred register class is found or hook @code{preferred_rename_class}\n\
5827 is not implemented.\n\
5828 Sometimes returning a more restrictive class makes better code. For\n\
5829 example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\n\
5830 smaller than instructions using @code{GENERIC_REGS}. By returning\n\
5831 @code{LO_REGS} from @code{preferred_rename_class}, code size can\n\
5832 be reduced.",
5833 reg_class_t, (reg_class_t rclass),
5834 default_preferred_rename_class)
5836 /* This target hook allows the backend to avoid unsafe substitution
5837 during register allocation. */
5838 DEFHOOK
5839 (cannot_substitute_mem_equiv_p,
5840 "A target hook which returns @code{true} if @var{subst} can't\n\
5841 substitute safely pseudos with equivalent memory values during\n\
5842 register allocation.\n\
5843 The default version of this target hook returns @code{false}.\n\
5844 On most machines, this default should be used. For generally\n\
5845 machines with non orthogonal register usage for addressing, such\n\
5846 as SH, this hook can be used to avoid excessive spilling.",
5847 bool, (rtx subst),
5848 hook_bool_rtx_false)
5850 /* This target hook allows the backend to legitimize base plus
5851 displacement addressing. */
5852 DEFHOOK
5853 (legitimize_address_displacement,
5854 "This hook tries to split address offset @var{orig_offset} into\n\
5855 two parts: one that should be added to the base address to create\n\
5856 a local anchor point, and an additional offset that can be applied\n\
5857 to the anchor to address a value of mode @var{mode}. The idea is that\n\
5858 the local anchor could be shared by other accesses to nearby locations.\n\
5860 The hook returns true if it succeeds, storing the offset of the\n\
5861 anchor from the base in @var{offset1} and the offset of the final address\n\
5862 from the anchor in @var{offset2}. The default implementation returns false.",
5863 bool, (rtx *offset1, rtx *offset2, poly_int64 orig_offset, machine_mode mode),
5864 default_legitimize_address_displacement)
5866 /* This target hook allows the backend to perform additional
5867 processing while initializing for variable expansion. */
5868 DEFHOOK
5869 (expand_to_rtl_hook,
5870 "This hook is called just before expansion into rtl, allowing the target\n\
5871 to perform additional initializations or analysis before the expansion.\n\
5872 For example, the rs6000 port uses it to allocate a scratch stack slot\n\
5873 for use in copying SDmode values between memory and floating point\n\
5874 registers whenever the function being expanded has any SDmode\n\
5875 usage.",
5876 void, (void),
5877 hook_void_void)
5879 /* This target hook allows the backend to perform additional
5880 instantiations on rtx that are not actually in insns yet,
5881 but will be later. */
5882 DEFHOOK
5883 (instantiate_decls,
5884 "This hook allows the backend to perform additional instantiations on rtl\n\
5885 that are not actually in any insns yet, but will be later.",
5886 void, (void),
5887 hook_void_void)
5889 DEFHOOK
5890 (hard_regno_nregs,
5891 "This hook returns the number of consecutive hard registers, starting\n\
5892 at register number @var{regno}, required to hold a value of mode\n\
5893 @var{mode}. This hook must never return zero, even if a register\n\
5894 cannot hold the requested mode - indicate that with\n\
5895 @code{TARGET_HARD_REGNO_MODE_OK} and/or\n\
5896 @code{TARGET_CAN_CHANGE_MODE_CLASS} instead.\n\
5898 The default definition returns the number of words in @var{mode}.",
5899 unsigned int, (unsigned int regno, machine_mode mode),
5900 default_hard_regno_nregs)
5902 DEFHOOK
5903 (hard_regno_mode_ok,
5904 "This hook returns true if it is permissible to store a value\n\
5905 of mode @var{mode} in hard register number @var{regno} (or in several\n\
5906 registers starting with that one). The default definition returns true\n\
5907 unconditionally.\n\
5909 You need not include code to check for the numbers of fixed registers,\n\
5910 because the allocation mechanism considers them to be always occupied.\n\
5912 @cindex register pairs\n\
5913 On some machines, double-precision values must be kept in even/odd\n\
5914 register pairs. You can implement that by defining this hook to reject\n\
5915 odd register numbers for such modes.\n\
5917 The minimum requirement for a mode to be OK in a register is that the\n\
5918 @samp{mov@var{mode}} instruction pattern support moves between the\n\
5919 register and other hard register in the same class and that moving a\n\
5920 value into the register and back out not alter it.\n\
5922 Since the same instruction used to move @code{word_mode} will work for\n\
5923 all narrower integer modes, it is not necessary on any machine for\n\
5924 this hook to distinguish between these modes, provided you define\n\
5925 patterns @samp{movhi}, etc., to take advantage of this. This is\n\
5926 useful because of the interaction between @code{TARGET_HARD_REGNO_MODE_OK}\n\
5927 and @code{TARGET_MODES_TIEABLE_P}; it is very desirable for all integer\n\
5928 modes to be tieable.\n\
5930 Many machines have special registers for floating point arithmetic.\n\
5931 Often people assume that floating point machine modes are allowed only\n\
5932 in floating point registers. This is not true. Any registers that\n\
5933 can hold integers can safely @emph{hold} a floating point machine\n\
5934 mode, whether or not floating arithmetic can be done on it in those\n\
5935 registers. Integer move instructions can be used to move the values.\n\
5937 On some machines, though, the converse is true: fixed-point machine\n\
5938 modes may not go in floating registers. This is true if the floating\n\
5939 registers normalize any value stored in them, because storing a\n\
5940 non-floating value there would garble it. In this case,\n\
5941 @code{TARGET_HARD_REGNO_MODE_OK} should reject fixed-point machine modes in\n\
5942 floating registers. But if the floating registers do not automatically\n\
5943 normalize, if you can store any bit pattern in one and retrieve it\n\
5944 unchanged without a trap, then any machine mode may go in a floating\n\
5945 register, so you can define this hook to say so.\n\
5947 The primary significance of special floating registers is rather that\n\
5948 they are the registers acceptable in floating point arithmetic\n\
5949 instructions. However, this is of no concern to\n\
5950 @code{TARGET_HARD_REGNO_MODE_OK}. You handle it by writing the proper\n\
5951 constraints for those instructions.\n\
5953 On some machines, the floating registers are especially slow to access,\n\
5954 so that it is better to store a value in a stack frame than in such a\n\
5955 register if floating point arithmetic is not being done. As long as the\n\
5956 floating registers are not in class @code{GENERAL_REGS}, they will not\n\
5957 be used unless some pattern's constraint asks for one.",
5958 bool, (unsigned int regno, machine_mode mode),
5959 hook_bool_uint_mode_true)
5961 DEFHOOK
5962 (modes_tieable_p,
5963 "This hook returns true if a value of mode @var{mode1} is accessible\n\
5964 in mode @var{mode2} without copying.\n\
5966 If @code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode1})} and\n\
5967 @code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode2})} are always\n\
5968 the same for any @var{r}, then\n\
5969 @code{TARGET_MODES_TIEABLE_P (@var{mode1}, @var{mode2})}\n\
5970 should be true. If they differ for any @var{r}, you should define\n\
5971 this hook to return false unless some other mechanism ensures the\n\
5972 accessibility of the value in a narrower mode.\n\
5974 You should define this hook to return true in as many cases as\n\
5975 possible since doing so will allow GCC to perform better register\n\
5976 allocation. The default definition returns true unconditionally.",
5977 bool, (machine_mode mode1, machine_mode mode2),
5978 hook_bool_mode_mode_true)
5980 /* Return true if is OK to use a hard register REGNO as scratch register
5981 in peephole2. */
5982 DEFHOOK
5983 (hard_regno_scratch_ok,
5984 "This target hook should return @code{true} if it is OK to use a hard register\n\
5985 @var{regno} as scratch reg in peephole2.\n\
5987 One common use of this macro is to prevent using of a register that\n\
5988 is not saved by a prologue in an interrupt handler.\n\
5990 The default version of this hook always returns @code{true}.",
5991 bool, (unsigned int regno),
5992 default_hard_regno_scratch_ok)
5994 DEFHOOK
5995 (hard_regno_call_part_clobbered,
5996 "ABIs usually specify that calls must preserve the full contents\n\
5997 of a particular register, or that calls can alter any part of a\n\
5998 particular register. This information is captured by the target macro\n\
5999 @code{CALL_REALLY_USED_REGISTERS}. However, some ABIs specify that calls\n\
6000 must preserve certain bits of a particular register but can alter others.\n\
6001 This hook should return true if this applies to at least one of the\n\
6002 registers in @samp{(reg:@var{mode} @var{regno})}, and if as a result the\n\
6003 call would alter part of the @var{mode} value. For example, if a call\n\
6004 preserves the low 32 bits of a 64-bit hard register @var{regno} but can\n\
6005 clobber the upper 32 bits, this hook should return true for a 64-bit mode\n\
6006 but false for a 32-bit mode.\n\
6008 The value of @var{abi_id} comes from the @code{predefined_function_abi}\n\
6009 structure that describes the ABI of the call; see the definition of the\n\
6010 structure for more details. If (as is usual) the target uses the same ABI\n\
6011 for all functions in a translation unit, @var{abi_id} is always 0.\n\
6013 The default implementation returns false, which is correct\n\
6014 for targets that don't have partly call-clobbered registers.",
6015 bool, (unsigned int abi_id, unsigned int regno, machine_mode mode),
6016 hook_bool_uint_uint_mode_false)
6018 DEFHOOK
6019 (get_multilib_abi_name,
6020 "This hook returns name of multilib ABI name.",
6021 const char *, (void),
6022 hook_constcharptr_void_null)
6024 /* Return the smallest number of different values for which it is best to
6025 use a jump-table instead of a tree of conditional branches. */
6026 DEFHOOK
6027 (case_values_threshold,
6028 "This function return the smallest number of different values for which it\n\
6029 is best to use a jump-table instead of a tree of conditional branches.\n\
6030 The default is four for machines with a @code{casesi} instruction and\n\
6031 five otherwise. This is best for most machines.",
6032 unsigned int, (void),
6033 default_case_values_threshold)
6035 DEFHOOK
6036 (starting_frame_offset,
6037 "This hook returns the offset from the frame pointer to the first local\n\
6038 variable slot to be allocated. If @code{FRAME_GROWS_DOWNWARD}, it is the\n\
6039 offset to @emph{end} of the first slot allocated, otherwise it is the\n\
6040 offset to @emph{beginning} of the first slot allocated. The default\n\
6041 implementation returns 0.",
6042 HOST_WIDE_INT, (void),
6043 hook_hwi_void_0)
6045 /* Optional callback to advise the target to compute the frame layout. */
6046 DEFHOOK
6047 (compute_frame_layout,
6048 "This target hook is called once each time the frame layout needs to be\n\
6049 recalculated. The calculations can be cached by the target and can then\n\
6050 be used by @code{INITIAL_ELIMINATION_OFFSET} instead of re-computing the\n\
6051 layout on every invocation of that hook. This is particularly useful\n\
6052 for targets that have an expensive frame layout function. Implementing\n\
6053 this callback is optional.",
6054 void, (void),
6055 hook_void_void)
6057 /* Return true if a function must have and use a frame pointer. */
6058 DEFHOOK
6059 (frame_pointer_required,
6060 "This target hook should return @code{true} if a function must have and use\n\
6061 a frame pointer. This target hook is called in the reload pass. If its return\n\
6062 value is @code{true} the function will have a frame pointer.\n\
6064 This target hook can in principle examine the current function and decide\n\
6065 according to the facts, but on most machines the constant @code{false} or the\n\
6066 constant @code{true} suffices. Use @code{false} when the machine allows code\n\
6067 to be generated with no frame pointer, and doing so saves some time or space.\n\
6068 Use @code{true} when there is no possible advantage to avoiding a frame\n\
6069 pointer.\n\
6071 In certain cases, the compiler does not know how to produce valid code\n\
6072 without a frame pointer. The compiler recognizes those cases and\n\
6073 automatically gives the function a frame pointer regardless of what\n\
6074 @code{targetm.frame_pointer_required} returns. You don't need to worry about\n\
6075 them.\n\
6077 In a function that does not require a frame pointer, the frame pointer\n\
6078 register can be allocated for ordinary usage, unless you mark it as a\n\
6079 fixed register. See @code{FIXED_REGISTERS} for more information.\n\
6081 Default return value is @code{false}.",
6082 bool, (void),
6083 hook_bool_void_false)
6085 /* Returns true if the compiler is allowed to try to replace register number
6086 from-reg with register number to-reg. */
6087 DEFHOOK
6088 (can_eliminate,
6089 "This target hook should return @code{true} if the compiler is allowed to\n\
6090 try to replace register number @var{from_reg} with register number\n\
6091 @var{to_reg}. This target hook will usually be @code{true}, since most of the\n\
6092 cases preventing register elimination are things that the compiler already\n\
6093 knows about.\n\
6095 Default return value is @code{true}.",
6096 bool, (const int from_reg, const int to_reg),
6097 hook_bool_const_int_const_int_true)
6099 /* Modify any or all of fixed_regs, call_used_regs, global_regs,
6100 reg_names, and reg_class_contents to account of the vagaries of the
6101 target. */
6102 DEFHOOK
6103 (conditional_register_usage,
6104 "This hook may conditionally modify five variables\n\
6105 @code{fixed_regs}, @code{call_used_regs}, @code{global_regs},\n\
6106 @code{reg_names}, and @code{reg_class_contents}, to take into account\n\
6107 any dependence of these register sets on target flags. The first three\n\
6108 of these are of type @code{char []} (interpreted as boolean vectors).\n\
6109 @code{global_regs} is a @code{const char *[]}, and\n\
6110 @code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is\n\
6111 called, @code{fixed_regs}, @code{call_used_regs},\n\
6112 @code{reg_class_contents}, and @code{reg_names} have been initialized\n\
6113 from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},\n\
6114 @code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.\n\
6115 @code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},\n\
6116 @option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}\n\
6117 command options have been applied.\n\
6119 @cindex disabling certain registers\n\
6120 @cindex controlling register usage\n\
6121 If the usage of an entire class of registers depends on the target\n\
6122 flags, you may indicate this to GCC by using this macro to modify\n\
6123 @code{fixed_regs} and @code{call_used_regs} to 1 for each of the\n\
6124 registers in the classes which should not be used by GCC@. Also make\n\
6125 @code{define_register_constraint}s return @code{NO_REGS} for constraints\n\
6126 that shouldn't be used.\n\
6128 (However, if this class is not included in @code{GENERAL_REGS} and all\n\
6129 of the insn patterns whose constraints permit this class are\n\
6130 controlled by target switches, then GCC will automatically avoid using\n\
6131 these registers when the target switches are opposed to them.)",
6132 void, (void),
6133 hook_void_void)
6135 DEFHOOK
6136 (stack_clash_protection_alloca_probe_range,
6137 "Some targets have an ABI defined interval for which no probing needs to be done.\n\
6138 When a probe does need to be done this same interval is used as the probe distance\n\
6139 up when doing stack clash protection for alloca.\n\
6140 On such targets this value can be set to override the default probing up interval.\n\
6141 Define this variable to return nonzero if such a probe range is required or zero otherwise.\n\
6142 Defining this hook also requires your functions which make use of alloca to have at least 8 byes\n\
6143 of outgoing arguments. If this is not the case the stack will be corrupted.\n\
6144 You need not define this macro if it would always have the value zero.",
6145 HOST_WIDE_INT, (void),
6146 default_stack_clash_protection_alloca_probe_range)
6149 /* Functions specific to the C family of frontends. */
6150 #undef HOOK_PREFIX
6151 #define HOOK_PREFIX "TARGET_C_"
6152 HOOK_VECTOR (TARGET_C, c)
6154 /* ??? Documenting this hook requires a GFDL license grant. */
6155 DEFHOOK_UNDOC
6156 (mode_for_suffix,
6157 "Return machine mode for non-standard constant literal suffix @var{c},\
6158 or VOIDmode if non-standard suffixes are unsupported.",
6159 machine_mode, (char c),
6160 default_mode_for_suffix)
6162 DEFHOOK
6163 (excess_precision,
6164 "Return a value, with the same meaning as the C99 macro\n\
6165 @code{FLT_EVAL_METHOD} that describes which excess precision should be\n\
6166 applied. @var{type} is either @code{EXCESS_PRECISION_TYPE_IMPLICIT},\n\
6167 @code{EXCESS_PRECISION_TYPE_FAST},\n\
6168 @code{EXCESS_PRECISION_TYPE_STANDARD}, or\n\
6169 @code{EXCESS_PRECISION_TYPE_FLOAT16}. For\n\
6170 @code{EXCESS_PRECISION_TYPE_IMPLICIT}, the target should return which\n\
6171 precision and range operations will be implictly evaluated in regardless\n\
6172 of the excess precision explicitly added. For\n\
6173 @code{EXCESS_PRECISION_TYPE_STANDARD}, \n\
6174 @code{EXCESS_PRECISION_TYPE_FLOAT16}, and\n\
6175 @code{EXCESS_PRECISION_TYPE_FAST}, the target should return the\n\
6176 explicit excess precision that should be added depending on the\n\
6177 value set for @option{-fexcess-precision=@r{[}standard@r{|}fast@r{]}}.\n\
6178 Note that unpredictable explicit excess precision does not make sense,\n\
6179 so a target should never return @code{FLT_EVAL_METHOD_UNPREDICTABLE}\n\
6180 when @var{type} is @code{EXCESS_PRECISION_TYPE_STANDARD},\n\
6181 @code{EXCESS_PRECISION_TYPE_FLOAT16} or\n\
6182 @code{EXCESS_PRECISION_TYPE_FAST}.",
6183 enum flt_eval_method, (enum excess_precision_type type),
6184 default_excess_precision)
6186 HOOK_VECTOR_END (c)
6188 /* Functions specific to the C++ frontend. */
6189 #undef HOOK_PREFIX
6190 #define HOOK_PREFIX "TARGET_CXX_"
6191 HOOK_VECTOR (TARGET_CXX, cxx)
6193 /* Return the integer type used for guard variables. */
6194 DEFHOOK
6195 (guard_type,
6196 "Define this hook to override the integer type used for guard variables.\n\
6197 These are used to implement one-time construction of static objects. The\n\
6198 default is long_long_integer_type_node.",
6199 tree, (void),
6200 default_cxx_guard_type)
6202 /* Return true if only the low bit of the guard should be tested. */
6203 DEFHOOK
6204 (guard_mask_bit,
6205 "This hook determines how guard variables are used. It should return\n\
6206 @code{false} (the default) if the first byte should be used. A return value of\n\
6207 @code{true} indicates that only the least significant bit should be used.",
6208 bool, (void),
6209 hook_bool_void_false)
6211 /* Returns the size of the array cookie for an array of type. */
6212 DEFHOOK
6213 (get_cookie_size,
6214 "This hook returns the size of the cookie to use when allocating an array\n\
6215 whose elements have the indicated @var{type}. Assumes that it is already\n\
6216 known that a cookie is needed. The default is\n\
6217 @code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the\n\
6218 IA64/Generic C++ ABI@.",
6219 tree, (tree type),
6220 default_cxx_get_cookie_size)
6222 /* Returns true if the element size should be stored in the array cookie. */
6223 DEFHOOK
6224 (cookie_has_size,
6225 "This hook should return @code{true} if the element size should be stored in\n\
6226 array cookies. The default is to return @code{false}.",
6227 bool, (void),
6228 hook_bool_void_false)
6230 /* Allows backends to perform additional processing when
6231 deciding if a class should be exported or imported. */
6232 DEFHOOK
6233 (import_export_class,
6234 "If defined by a backend this hook allows the decision made to export\n\
6235 class @var{type} to be overruled. Upon entry @var{import_export}\n\
6236 will contain 1 if the class is going to be exported, @minus{}1 if it is going\n\
6237 to be imported and 0 otherwise. This function should return the\n\
6238 modified value and perform any other actions necessary to support the\n\
6239 backend's targeted operating system.",
6240 int, (tree type, int import_export), NULL)
6242 /* Returns true if constructors and destructors return "this". */
6243 DEFHOOK
6244 (cdtor_returns_this,
6245 "This hook should return @code{true} if constructors and destructors return\n\
6246 the address of the object created/destroyed. The default is to return\n\
6247 @code{false}.",
6248 bool, (void),
6249 hook_bool_void_false)
6251 /* Returns true if the key method for a class can be an inline
6252 function, so long as it is not declared inline in the class
6253 itself. Returning true is the behavior required by the Itanium C++ ABI. */
6254 DEFHOOK
6255 (key_method_may_be_inline,
6256 "This hook returns true if the key method for a class (i.e., the method\n\
6257 which, if defined in the current translation unit, causes the virtual\n\
6258 table to be emitted) may be an inline function. Under the standard\n\
6259 Itanium C++ ABI the key method may be an inline function so long as\n\
6260 the function is not declared inline in the class definition. Under\n\
6261 some variants of the ABI, an inline function can never be the key\n\
6262 method. The default is to return @code{true}.",
6263 bool, (void),
6264 hook_bool_void_true)
6266 DEFHOOK
6267 (determine_class_data_visibility,
6268 "@var{decl} is a virtual table, virtual table table, typeinfo object,\n\
6269 or other similar implicit class data object that will be emitted with\n\
6270 external linkage in this translation unit. No ELF visibility has been\n\
6271 explicitly specified. If the target needs to specify a visibility\n\
6272 other than that of the containing class, use this hook to set\n\
6273 @code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
6274 void, (tree decl),
6275 hook_void_tree)
6277 /* Returns true (the default) if virtual tables and other
6278 similar implicit class data objects are always COMDAT if they
6279 have external linkage. If this hook returns false, then
6280 class data for classes whose virtual table will be emitted in
6281 only one translation unit will not be COMDAT. */
6282 DEFHOOK
6283 (class_data_always_comdat,
6284 "This hook returns true (the default) if virtual tables and other\n\
6285 similar implicit class data objects are always COMDAT if they have\n\
6286 external linkage. If this hook returns false, then class data for\n\
6287 classes whose virtual table will be emitted in only one translation\n\
6288 unit will not be COMDAT.",
6289 bool, (void),
6290 hook_bool_void_true)
6292 /* Returns true (the default) if the RTTI for the basic types,
6293 which is always defined in the C++ runtime, should be COMDAT;
6294 false if it should not be COMDAT. */
6295 DEFHOOK
6296 (library_rtti_comdat,
6297 "This hook returns true (the default) if the RTTI information for\n\
6298 the basic types which is defined in the C++ runtime should always\n\
6299 be COMDAT, false if it should not be COMDAT.",
6300 bool, (void),
6301 hook_bool_void_true)
6303 /* Returns true if __aeabi_atexit should be used to register static
6304 destructors. */
6305 DEFHOOK
6306 (use_aeabi_atexit,
6307 "This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)\n\
6308 should be used to register static destructors when @option{-fuse-cxa-atexit}\n\
6309 is in effect. The default is to return false to use @code{__cxa_atexit}.",
6310 bool, (void),
6311 hook_bool_void_false)
6313 /* Returns true if target may use atexit in the same manner as
6314 __cxa_atexit to register static destructors. */
6315 DEFHOOK
6316 (use_atexit_for_cxa_atexit,
6317 "This hook returns true if the target @code{atexit} function can be used\n\
6318 in the same manner as @code{__cxa_atexit} to register C++ static\n\
6319 destructors. This requires that @code{atexit}-registered functions in\n\
6320 shared libraries are run in the correct order when the libraries are\n\
6321 unloaded. The default is to return false.",
6322 bool, (void),
6323 hook_bool_void_false)
6325 DEFHOOK
6326 (adjust_class_at_definition,
6327 "@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\n\
6328 been defined. Use this hook to make adjustments to the class (eg, tweak\n\
6329 visibility or perform any other required target modifications).",
6330 void, (tree type),
6331 hook_void_tree)
6333 DEFHOOK
6334 (decl_mangling_context,
6335 "Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
6336 tree, (const_tree decl),
6337 hook_tree_const_tree_null)
6339 HOOK_VECTOR_END (cxx)
6341 /* Functions and data for emulated TLS support. */
6342 #undef HOOK_PREFIX
6343 #define HOOK_PREFIX "TARGET_EMUTLS_"
6344 HOOK_VECTOR (TARGET_EMUTLS, emutls)
6346 /* Name of the address and common functions. */
6347 DEFHOOKPOD
6348 (get_address,
6349 "Contains the name of the helper function that uses a TLS control\n\
6350 object to locate a TLS instance. The default causes libgcc's\n\
6351 emulated TLS helper function to be used.",
6352 const char *, "__builtin___emutls_get_address")
6354 DEFHOOKPOD
6355 (register_common,
6356 "Contains the name of the helper function that should be used at\n\
6357 program startup to register TLS objects that are implicitly\n\
6358 initialized to zero. If this is @code{NULL}, all TLS objects will\n\
6359 have explicit initializers. The default causes libgcc's emulated TLS\n\
6360 registration function to be used.",
6361 const char *, "__builtin___emutls_register_common")
6363 /* Prefixes for proxy variable and template. */
6364 DEFHOOKPOD
6365 (var_section,
6366 "Contains the name of the section in which TLS control variables should\n\
6367 be placed. The default of @code{NULL} allows these to be placed in\n\
6368 any section.",
6369 const char *, NULL)
6371 DEFHOOKPOD
6372 (tmpl_section,
6373 "Contains the name of the section in which TLS initializers should be\n\
6374 placed. The default of @code{NULL} allows these to be placed in any\n\
6375 section.",
6376 const char *, NULL)
6378 /* Prefixes for proxy variable and template. */
6379 DEFHOOKPOD
6380 (var_prefix,
6381 "Contains the prefix to be prepended to TLS control variable names.\n\
6382 The default of @code{NULL} uses a target-specific prefix.",
6383 const char *, NULL)
6385 DEFHOOKPOD
6386 (tmpl_prefix,
6387 "Contains the prefix to be prepended to TLS initializer objects. The\n\
6388 default of @code{NULL} uses a target-specific prefix.",
6389 const char *, NULL)
6391 /* Function to generate field definitions of the proxy variable. */
6392 DEFHOOK
6393 (var_fields,
6394 "Specifies a function that generates the FIELD_DECLs for a TLS control\n\
6395 object type. @var{type} is the RECORD_TYPE the fields are for and\n\
6396 @var{name} should be filled with the structure tag, if the default of\n\
6397 @code{__emutls_object} is unsuitable. The default creates a type suitable\n\
6398 for libgcc's emulated TLS function.",
6399 tree, (tree type, tree *name),
6400 default_emutls_var_fields)
6402 /* Function to initialize a proxy variable. */
6403 DEFHOOK
6404 (var_init,
6405 "Specifies a function that generates the CONSTRUCTOR to initialize a\n\
6406 TLS control object. @var{var} is the TLS control object, @var{decl}\n\
6407 is the TLS object and @var{tmpl_addr} is the address of the\n\
6408 initializer. The default initializes libgcc's emulated TLS control object.",
6409 tree, (tree var, tree decl, tree tmpl_addr),
6410 default_emutls_var_init)
6412 /* Whether we are allowed to alter the usual alignment of the
6413 proxy variable. */
6414 DEFHOOKPOD
6415 (var_align_fixed,
6416 "Specifies whether the alignment of TLS control variable objects is\n\
6417 fixed and should not be increased as some backends may do to optimize\n\
6418 single objects. The default is false.",
6419 bool, false)
6421 /* Whether we can emit debug information for TLS vars. */
6422 DEFHOOKPOD
6423 (debug_form_tls_address,
6424 "Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor\n\
6425 may be used to describe emulated TLS control objects.",
6426 bool, false)
6428 HOOK_VECTOR_END (emutls)
6430 #undef HOOK_PREFIX
6431 #define HOOK_PREFIX "TARGET_OPTION_"
6432 HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)
6434 /* Function to validate the attribute((target(...))) strings. If
6435 the option is validated, the hook should also fill in
6436 DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
6437 DEFHOOK
6438 (valid_attribute_p,
6439 "This hook is called to parse @code{attribute(target(\"...\"))}, which\n\
6440 allows setting target-specific options on individual functions.\n\
6441 These function-specific options may differ\n\
6442 from the options specified on the command line. The hook should return\n\
6443 @code{true} if the options are valid.\n\
6445 The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
6446 the function declaration to hold a pointer to a target-specific\n\
6447 @code{struct cl_target_option} structure.",
6448 bool, (tree fndecl, tree name, tree args, int flags),
6449 default_target_option_valid_attribute_p)
6451 /* Function to save any extra target state in the target options structure. */
6452 DEFHOOK
6453 (save,
6454 "This hook is called to save any additional target-specific information\n\
6455 in the @code{struct cl_target_option} structure for function-specific\n\
6456 options from the @code{struct gcc_options} structure.\n\
6457 @xref{Option file format}.",
6458 void, (struct cl_target_option *ptr, struct gcc_options *opts,
6459 struct gcc_options *opts_set), NULL)
6461 /* Function to restore any extra target state from the target options
6462 structure. */
6463 DEFHOOK
6464 (restore,
6465 "This hook is called to restore any additional target-specific\n\
6466 information in the @code{struct cl_target_option} structure for\n\
6467 function-specific options to the @code{struct gcc_options} structure.",
6468 void, (struct gcc_options *opts, struct gcc_options *opts_set,
6469 struct cl_target_option *ptr), NULL)
6471 /* Function to update target-specific option information after being
6472 streamed in. */
6473 DEFHOOK
6474 (post_stream_in,
6475 "This hook is called to update target-specific information in the\n\
6476 @code{struct cl_target_option} structure after it is streamed in from\n\
6477 LTO bytecode.",
6478 void, (struct cl_target_option *ptr), NULL)
6480 /* Function to print any extra target state from the target options
6481 structure. */
6482 DEFHOOK
6483 (print,
6484 "This hook is called to print any additional target-specific\n\
6485 information in the @code{struct cl_target_option} structure for\n\
6486 function-specific options.",
6487 void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)
6489 /* Function to parse arguments to be validated for #pragma target, and to
6490 change the state if the options are valid. If the first argument is
6491 NULL, the second argument specifies the default options to use. Return
6492 true if the options are valid, and set the current state. */
6493 DEFHOOK
6494 (pragma_parse,
6495 "This target hook parses the options for @code{#pragma GCC target}, which\n\
6496 sets the target-specific options for functions that occur later in the\n\
6497 input stream. The options accepted should be the same as those handled by the\n\
6498 @code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.",
6499 bool, (tree args, tree pop_target),
6500 default_target_option_pragma_parse)
6502 /* Do option overrides for the target. */
6503 DEFHOOK
6504 (override,
6505 "Sometimes certain combinations of command options do not make sense on\n\
6506 a particular target machine. You can override the hook\n\
6507 @code{TARGET_OPTION_OVERRIDE} to take account of this. This hooks is called\n\
6508 once just after all the command options have been parsed.\n\
6510 Don't use this hook to turn on various extra optimizations for\n\
6511 @option{-O}. That is what @code{TARGET_OPTION_OPTIMIZATION} is for.\n\
6513 If you need to do something whenever the optimization level is\n\
6514 changed via the optimize attribute or pragma, see\n\
6515 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}",
6516 void, (void),
6517 hook_void_void)
6519 /* This function returns true if DECL1 and DECL2 are versions of the same
6520 function. DECL1 and DECL2 are function versions if and only if they
6521 have the same function signature and different target specific attributes,
6522 that is, they are compiled for different target machines. */
6523 DEFHOOK
6524 (function_versions,
6525 "This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are\n\
6526 versions of the same function. @var{DECL1} and @var{DECL2} are function\n\
6527 versions if and only if they have the same function signature and\n\
6528 different target specific attributes, that is, they are compiled for\n\
6529 different target machines.",
6530 bool, (tree decl1, tree decl2),
6531 hook_bool_tree_tree_false)
6533 /* Function to determine if one function can inline another function. */
6534 #undef HOOK_PREFIX
6535 #define HOOK_PREFIX "TARGET_"
6536 DEFHOOK
6537 (can_inline_p,
6538 "This target hook returns @code{false} if the @var{caller} function\n\
6539 cannot inline @var{callee}, based on target specific information. By\n\
6540 default, inlining is not allowed if the callee function has function\n\
6541 specific target options and the caller does not use the same options.",
6542 bool, (tree caller, tree callee),
6543 default_target_can_inline_p)
6545 DEFHOOK
6546 (update_ipa_fn_target_info,
6547 "Allow target to analyze all gimple statements for the given function to\n\
6548 record and update some target specific information for inlining. A typical\n\
6549 example is that a caller with one isa feature disabled is normally not\n\
6550 allowed to inline a callee with that same isa feature enabled even which is\n\
6551 attributed by always_inline, but with the conservative analysis on all\n\
6552 statements of the callee if we are able to guarantee the callee does not\n\
6553 exploit any instructions from the mismatch isa feature, it would be safe to\n\
6554 allow the caller to inline the callee.\n\
6555 @var{info} is one @code{unsigned int} value to record information in which\n\
6556 one set bit indicates one corresponding feature is detected in the analysis,\n\
6557 @var{stmt} is the statement being analyzed. Return true if target still\n\
6558 need to analyze the subsequent statements, otherwise return false to stop\n\
6559 subsequent analysis.\n\
6560 The default version of this hook returns false.",
6561 bool, (unsigned int& info, const gimple* stmt),
6562 default_update_ipa_fn_target_info)
6564 DEFHOOK
6565 (need_ipa_fn_target_info,
6566 "Allow target to check early whether it is necessary to analyze all gimple\n\
6567 statements in the given function to update target specific information for\n\
6568 inlining. See hook @code{update_ipa_fn_target_info} for usage example of\n\
6569 target specific information. This hook is expected to be invoked ahead of\n\
6570 the iterating with hook @code{update_ipa_fn_target_info}.\n\
6571 @var{decl} is the function being analyzed, @var{info} is the same as what\n\
6572 in hook @code{update_ipa_fn_target_info}, target can do one time update\n\
6573 into @var{info} without iterating for some case. Return true if target\n\
6574 decides to analyze all gimple statements to collect information, otherwise\n\
6575 return false.\n\
6576 The default version of this hook returns false.",
6577 bool, (const_tree decl, unsigned int& info),
6578 default_need_ipa_fn_target_info)
6580 DEFHOOK
6581 (relayout_function,
6582 "This target hook fixes function @var{fndecl} after attributes are processed.\n\
6583 Default does nothing. On ARM, the default function's alignment is updated\n\
6584 with the attribute target.",
6585 void, (tree fndecl),
6586 hook_void_tree)
6588 HOOK_VECTOR_END (target_option)
6590 /* For targets that need to mark extra registers as live on entry to
6591 the function, they should define this target hook and set their
6592 bits in the bitmap passed in. */
6593 DEFHOOK
6594 (extra_live_on_entry,
6595 "Add any hard registers to @var{regs} that are live on entry to the\n\
6596 function. This hook only needs to be defined to provide registers that\n\
6597 cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved\n\
6598 registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,\n\
6599 TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,\n\
6600 FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.",
6601 void, (bitmap regs),
6602 hook_void_bitmap)
6604 /* Targets should define this target hook to mark that non-callee clobbers are
6605 present in CALL_INSN_FUNCTION_USAGE for all the calls that bind to a local
6606 definition. */
6607 DEFHOOKPOD
6608 (call_fusage_contains_non_callee_clobbers,
6609 "Set to true if each call that binds to a local definition explicitly\n\
6610 clobbers or sets all non-fixed registers modified by performing the call.\n\
6611 That is, by the call pattern itself, or by code that might be inserted by the\n\
6612 linker (e.g.@: stubs, veneers, branch islands), but not including those\n\
6613 modifiable by the callee. The affected registers may be mentioned explicitly\n\
6614 in the call pattern, or included as clobbers in CALL_INSN_FUNCTION_USAGE.\n\
6615 The default version of this hook is set to false. The purpose of this hook\n\
6616 is to enable the fipa-ra optimization.",
6617 bool,
6618 false)
6620 /* Fill in additional registers set up by prologue into a regset. */
6621 DEFHOOK
6622 (set_up_by_prologue,
6623 "This hook should add additional registers that are computed by the prologue\n\
6624 to the hard regset for shrink-wrapping optimization purposes.",
6625 void, (struct hard_reg_set_container *),
6626 NULL)
6628 /* For targets that have attributes that can affect whether a
6629 function's return statements need checking. For instance a 'naked'
6630 function attribute. */
6631 DEFHOOK
6632 (warn_func_return,
6633 "True if a function's return statements should be checked for matching\n\
6634 the function's return type. This includes checking for falling off the end\n\
6635 of a non-void function. Return false if no such check should be made.",
6636 bool, (tree),
6637 hook_bool_tree_true)
6639 #undef HOOK_PREFIX
6640 #define HOOK_PREFIX "TARGET_SHRINK_WRAP_"
6641 HOOK_VECTOR (TARGET_SHRINK_WRAP_HOOKS, shrink_wrap)
6643 DEFHOOK
6644 (get_separate_components,
6645 "This hook should return an @code{sbitmap} with the bits set for those\n\
6646 components that can be separately shrink-wrapped in the current function.\n\
6647 Return @code{NULL} if the current function should not get any separate\n\
6648 shrink-wrapping.\n\
6649 Don't define this hook if it would always return @code{NULL}.\n\
6650 If it is defined, the other hooks in this group have to be defined as well.",
6651 sbitmap, (void),
6652 NULL)
6654 DEFHOOK
6655 (components_for_bb,
6656 "This hook should return an @code{sbitmap} with the bits set for those\n\
6657 components where either the prologue component has to be executed before\n\
6658 the @code{basic_block}, or the epilogue component after it, or both.",
6659 sbitmap, (basic_block),
6660 NULL)
6662 DEFHOOK
6663 (disqualify_components,
6664 "This hook should clear the bits in the @var{components} bitmap for those\n\
6665 components in @var{edge_components} that the target cannot handle on edge\n\
6666 @var{e}, where @var{is_prologue} says if this is for a prologue or an\n\
6667 epilogue instead.",
6668 void, (sbitmap components, edge e, sbitmap edge_components, bool is_prologue),
6669 NULL)
6671 DEFHOOK
6672 (emit_prologue_components,
6673 "Emit prologue insns for the components indicated by the parameter.",
6674 void, (sbitmap),
6675 NULL)
6677 DEFHOOK
6678 (emit_epilogue_components,
6679 "Emit epilogue insns for the components indicated by the parameter.",
6680 void, (sbitmap),
6681 NULL)
6683 DEFHOOK
6684 (set_handled_components,
6685 "Mark the components in the parameter as handled, so that the\n\
6686 @code{prologue} and @code{epilogue} named patterns know to ignore those\n\
6687 components. The target code should not hang on to the @code{sbitmap}, it\n\
6688 will be deleted after this call.",
6689 void, (sbitmap),
6690 NULL)
6692 HOOK_VECTOR_END (shrink_wrap)
6693 #undef HOOK_PREFIX
6694 #define HOOK_PREFIX "TARGET_"
6696 /* Determine the type of unwind info to emit for debugging. */
6697 DEFHOOK
6698 (debug_unwind_info,
6699 "This hook defines the mechanism that will be used for describing frame\n\
6700 unwind information to the debugger. Normally the hook will return\n\
6701 @code{UI_DWARF2} if DWARF 2 debug information is enabled, and\n\
6702 return @code{UI_NONE} otherwise.\n\
6704 A target may return @code{UI_DWARF2} even when DWARF 2 debug information\n\
6705 is disabled in order to always output DWARF 2 frame information.\n\
6707 A target may return @code{UI_TARGET} if it has ABI specified unwind tables.\n\
6708 This will suppress generation of the normal debug frame unwind information.",
6709 enum unwind_info_type, (void),
6710 default_debug_unwind_info)
6712 DEFHOOK
6713 (reset_location_view,
6714 "This hook, if defined, enables -ginternal-reset-location-views, and\n\
6715 uses its result to override cases in which the estimated min insn\n\
6716 length might be nonzero even when a PC advance (i.e., a view reset)\n\
6717 cannot be taken for granted.\n\
6719 If the hook is defined, it must return a positive value to indicate\n\
6720 the insn definitely advances the PC, and so the view number can be\n\
6721 safely assumed to be reset; a negative value to mean the insn\n\
6722 definitely does not advance the PC, and os the view number must not\n\
6723 be reset; or zero to decide based on the estimated insn length.\n\
6725 If insn length is to be regarded as reliable, set the hook to\n\
6726 @code{hook_int_rtx_insn_0}.",
6727 int, (rtx_insn *), NULL)
6729 /* The code parameter should be of type enum rtx_code but this is not
6730 defined at this time. */
6731 DEFHOOK
6732 (canonicalize_comparison,
6733 "On some machines not all possible comparisons are defined, but you can\n\
6734 convert an invalid comparison into a valid one. For example, the Alpha\n\
6735 does not have a @code{GT} comparison, but you can use an @code{LT}\n\
6736 comparison instead and swap the order of the operands.\n\
6738 On such machines, implement this hook to do any required conversions.\n\
6739 @var{code} is the initial comparison code and @var{op0} and @var{op1}\n\
6740 are the left and right operands of the comparison, respectively. If\n\
6741 @var{op0_preserve_value} is @code{true} the implementation is not\n\
6742 allowed to change the value of @var{op0} since the value might be used\n\
6743 in RTXs which aren't comparisons. E.g. the implementation is not\n\
6744 allowed to swap operands in that case.\n\
6746 GCC will not assume that the comparison resulting from this macro is\n\
6747 valid but will see if the resulting insn matches a pattern in the\n\
6748 @file{md} file.\n\
6750 You need not to implement this hook if it would never change the\n\
6751 comparison code or operands.",
6752 void, (int *code, rtx *op0, rtx *op1, bool op0_preserve_value),
6753 default_canonicalize_comparison)
6755 DEFHOOK
6756 (min_arithmetic_precision,
6757 "On some RISC architectures with 64-bit registers, the processor also\n\
6758 maintains 32-bit condition codes that make it possible to do real 32-bit\n\
6759 arithmetic, although the operations are performed on the full registers.\n\
6761 On such architectures, defining this hook to 32 tells the compiler to try\n\
6762 using 32-bit arithmetical operations setting the condition codes instead\n\
6763 of doing full 64-bit arithmetic.\n\
6765 More generally, define this hook on RISC architectures if you want the\n\
6766 compiler to try using arithmetical operations setting the condition codes\n\
6767 with a precision lower than the word precision.\n\
6769 You need not define this hook if @code{WORD_REGISTER_OPERATIONS} is not\n\
6770 defined to 1.",
6771 unsigned int, (void), default_min_arithmetic_precision)
6773 DEFHOOKPOD
6774 (atomic_test_and_set_trueval,
6775 "This value should be set if the result written by\n\
6776 @code{atomic_test_and_set} is not exactly 1, i.e.@: the\n\
6777 @code{bool} @code{true}.",
6778 unsigned char, 1)
6780 /* Return an unsigned int representing the alignment (in bits) of the atomic
6781 type which maps to machine MODE. This allows alignment to be overridden
6782 as needed. */
6783 DEFHOOK
6784 (atomic_align_for_mode,
6785 "If defined, this function returns an appropriate alignment in bits for an\n\
6786 atomic object of machine_mode @var{mode}. If 0 is returned then the\n\
6787 default alignment for the specified mode is used.",
6788 unsigned int, (machine_mode mode),
6789 hook_uint_mode_0)
6791 DEFHOOK
6792 (atomic_assign_expand_fenv,
6793 "ISO C11 requires atomic compound assignments that may raise floating-point\n\
6794 exceptions to raise exceptions corresponding to the arithmetic operation\n\
6795 whose result was successfully stored in a compare-and-exchange sequence.\n\
6796 This requires code equivalent to calls to @code{feholdexcept},\n\
6797 @code{feclearexcept} and @code{feupdateenv} to be generated at\n\
6798 appropriate points in the compare-and-exchange sequence. This hook should\n\
6799 set @code{*@var{hold}} to an expression equivalent to the call to\n\
6800 @code{feholdexcept}, @code{*@var{clear}} to an expression equivalent to\n\
6801 the call to @code{feclearexcept} and @code{*@var{update}} to an expression\n\
6802 equivalent to the call to @code{feupdateenv}. The three expressions are\n\
6803 @code{NULL_TREE} on entry to the hook and may be left as @code{NULL_TREE}\n\
6804 if no code is required in a particular place. The default implementation\n\
6805 leaves all three expressions as @code{NULL_TREE}. The\n\
6806 @code{__atomic_feraiseexcept} function from @code{libatomic} may be of use\n\
6807 as part of the code generated in @code{*@var{update}}.",
6808 void, (tree *hold, tree *clear, tree *update),
6809 default_atomic_assign_expand_fenv)
6811 /* Leave the boolean fields at the end. */
6813 /* True if we can create zeroed data by switching to a BSS section
6814 and then using ASM_OUTPUT_SKIP to allocate the space. */
6815 DEFHOOKPOD
6816 (have_switchable_bss_sections,
6817 "This flag is true if we can create zeroed data by switching to a BSS\n\
6818 section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.\n\
6819 This is true on most ELF targets.",
6820 bool, false)
6822 /* True if "native" constructors and destructors are supported,
6823 false if we're using collect2 for the job. */
6824 DEFHOOKPOD
6825 (have_ctors_dtors,
6826 "This value is true if the target supports some ``native'' method of\n\
6827 collecting constructors and destructors to be run at startup and exit.\n\
6828 It is false if we must use @command{collect2}.",
6829 bool, false)
6831 /* True if the target wants DTORs to be run from cxa_atexit. */
6832 DEFHOOKPOD
6833 (dtors_from_cxa_atexit,
6834 "This value is true if the target wants destructors to be queued to be\n\
6835 run from __cxa_atexit. If this is the case then, for each priority level,\n\
6836 a new constructor will be entered that registers the destructors for that\n\
6837 level with __cxa_atexit (and there will be no destructors emitted).\n\
6838 It is false the method implied by @code{have_ctors_dtors} is used.",
6839 bool, false)
6841 /* True if thread-local storage is supported. */
6842 DEFHOOKPOD
6843 (have_tls,
6844 "Contains the value true if the target supports thread-local storage.\n\
6845 The default value is false.",
6846 bool, false)
6848 /* True if a small readonly data section is supported. */
6849 DEFHOOKPOD
6850 (have_srodata_section,
6851 "Contains the value true if the target places read-only\n\
6852 ``small data'' into a separate section. The default value is false.",
6853 bool, false)
6855 /* True if EH frame info sections should be zero-terminated. */
6856 DEFHOOKPOD
6857 (terminate_dw2_eh_frame_info,
6858 "Contains the value true if the target should add a zero word onto the\n\
6859 end of a Dwarf-2 frame info section when used for exception handling.\n\
6860 Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and\n\
6861 true otherwise.",
6862 bool, true)
6864 /* True if #NO_APP should be emitted at the beginning of assembly output. */
6865 DEFHOOKPOD
6866 (asm_file_start_app_off,
6867 "If this flag is true, the text of the macro @code{ASM_APP_OFF} will be\n\
6868 printed as the very first line in the assembly file, unless\n\
6869 @option{-fverbose-asm} is in effect. (If that macro has been defined\n\
6870 to the empty string, this variable has no effect.) With the normal\n\
6871 definition of @code{ASM_APP_OFF}, the effect is to notify the GNU\n\
6872 assembler that it need not bother stripping comments or extra\n\
6873 whitespace from its input. This allows it to work a bit faster.\n\
6875 The default is false. You should not set it to true unless you have\n\
6876 verified that your port does not generate any extra whitespace or\n\
6877 comments that will cause GAS to issue errors in NO_APP mode.",
6878 bool, false)
6880 /* True if output_file_directive should be called for main_input_filename
6881 at the beginning of assembly output. */
6882 DEFHOOKPOD
6883 (asm_file_start_file_directive,
6884 "If this flag is true, @code{output_file_directive} will be called\n\
6885 for the primary source file, immediately after printing\n\
6886 @code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect\n\
6887 this to be done. The default is false.",
6888 bool, false)
6890 /* Returns true if we should generate exception tables for use with the
6891 ARM EABI. The effects the encoding of function exception specifications. */
6892 DEFHOOKPOD
6893 (arm_eabi_unwinder,
6894 "This flag should be set to @code{true} on targets that use an ARM EABI\n\
6895 based unwinding library, and @code{false} on other targets. This effects\n\
6896 the format of unwinding tables, and how the unwinder in entered after\n\
6897 running a cleanup. The default is @code{false}.",
6898 bool, false)
6900 DEFHOOKPOD
6901 (want_debug_pub_sections,
6902 "True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\n\
6903 should be emitted. These sections are not used on most platforms, and\n\
6904 in particular GDB does not use them.",
6905 bool, false)
6907 DEFHOOKPOD
6908 (delay_sched2,
6909 "True if sched2 is not to be run at its normal place.\n\
6910 This usually means it will be run as part of machine-specific reorg.",
6911 bool, false)
6913 DEFHOOKPOD
6914 (delay_vartrack,
6915 "True if vartrack is not to be run at its normal place.\n\
6916 This usually means it will be run as part of machine-specific reorg.",
6917 bool, false)
6919 DEFHOOKPOD
6920 (no_register_allocation,
6921 "True if register allocation and the passes\n\
6922 following it should not be run. Usually true only for virtual assembler\n\
6923 targets.",
6924 bool, false)
6926 /* Leave the boolean fields at the end. */
6928 /* Functions related to mode switching. */
6929 #undef HOOK_PREFIX
6930 #define HOOK_PREFIX "TARGET_MODE_"
6931 HOOK_VECTOR (TARGET_TOGGLE_, mode_switching)
6933 DEFHOOK
6934 (emit,
6935 "Generate one or more insns to set @var{entity} to @var{mode}.\n\
6936 @var{hard_reg_live} is the set of hard registers live at the point where\n\
6937 the insn(s) are to be inserted. @var{prev_moxde} indicates the mode\n\
6938 to switch from. Sets of a lower numbered entity will be emitted before\n\
6939 sets of a higher numbered entity to a mode of the same or lower priority.",
6940 void, (int entity, int mode, int prev_mode, HARD_REG_SET regs_live), NULL)
6942 DEFHOOK
6943 (needed,
6944 "@var{entity} is an integer specifying a mode-switched entity.\n\
6945 If @code{OPTIMIZE_MODE_SWITCHING} is defined, you must define this macro\n\
6946 to return an integer value not larger than the corresponding element\n\
6947 in @code{NUM_MODES_FOR_MODE_SWITCHING}, to denote the mode that @var{entity}\n\
6948 must be switched into prior to the execution of @var{insn}.",
6949 int, (int entity, rtx_insn *insn), NULL)
6951 DEFHOOK
6952 (after,
6953 "@var{entity} is an integer specifying a mode-switched entity.\n\
6954 If this macro is defined, it is evaluated for every @var{insn} during mode\n\
6955 switching. It determines the mode that an insn results\n\
6956 in (if different from the incoming mode).",
6957 int, (int entity, int mode, rtx_insn *insn), NULL)
6959 DEFHOOK
6960 (entry,
6961 "If this macro is defined, it is evaluated for every @var{entity} that\n\
6962 needs mode switching. It should evaluate to an integer, which is a mode\n\
6963 that @var{entity} is assumed to be switched to at function entry.\n\
6964 If @code{TARGET_MODE_ENTRY} is defined then @code{TARGET_MODE_EXIT}\n\
6965 must be defined.",
6966 int, (int entity), NULL)
6968 DEFHOOK
6969 (exit,
6970 "If this macro is defined, it is evaluated for every @var{entity} that\n\
6971 needs mode switching. It should evaluate to an integer, which is a mode\n\
6972 that @var{entity} is assumed to be switched to at function exit.\n\
6973 If @code{TARGET_MODE_EXIT} is defined then @code{TARGET_MODE_ENTRY}\n\
6974 must be defined.",
6975 int, (int entity), NULL)
6977 DEFHOOK
6978 (priority,
6979 "This macro specifies the order in which modes for @var{entity}\n\
6980 are processed. 0 is the highest priority,\n\
6981 @code{NUM_MODES_FOR_MODE_SWITCHING[@var{entity}] - 1} the lowest.\n\
6982 The value of the macro should be an integer designating a mode\n\
6983 for @var{entity}. For any fixed @var{entity}, @code{mode_priority}\n\
6984 (@var{entity}, @var{n}) shall be a bijection in 0 @dots{}\n\
6985 @code{num_modes_for_mode_switching[@var{entity}] - 1}.",
6986 int, (int entity, int n), NULL)
6988 HOOK_VECTOR_END (mode_switching)
6990 #undef HOOK_PREFIX
6991 #define HOOK_PREFIX "TARGET_MEMTAG_"
6992 HOOK_VECTOR (TARGET_MEMTAG_, memtag)
6994 DEFHOOK
6995 (can_tag_addresses,
6996 "True if the backend architecture naturally supports ignoring some region\n\
6997 of pointers. This feature means that @option{-fsanitize=hwaddress} can\n\
6998 work.\n\
7000 At preset, this feature does not support address spaces. It also requires\n\
7001 @code{Pmode} to be the same as @code{ptr_mode}.",
7002 bool, (), default_memtag_can_tag_addresses)
7004 DEFHOOK
7005 (tag_size,
7006 "Return the size of a tag (in bits) for this platform.\n\
7008 The default returns 8.",
7009 uint8_t, (), default_memtag_tag_size)
7011 DEFHOOK
7012 (granule_size,
7013 "Return the size in real memory that each byte in shadow memory refers to.\n\
7014 I.e. if a variable is @var{X} bytes long in memory, then this hook should\n\
7015 return the value @var{Y} such that the tag in shadow memory spans\n\
7016 @var{X}/@var{Y} bytes.\n\
7018 Most variables will need to be aligned to this amount since two variables\n\
7019 that are neighbors in memory and share a tag granule would need to share\n\
7020 the same tag.\n\
7022 The default returns 16.",
7023 uint8_t, (), default_memtag_granule_size)
7025 DEFHOOK
7026 (insert_random_tag,
7027 "Return an RTX representing the value of @var{untagged} but with a\n\
7028 (possibly) random tag in it.\n\
7029 Put that value into @var{target} if it is convenient to do so.\n\
7030 This function is used to generate a tagged base for the current stack frame.",
7031 rtx, (rtx untagged, rtx target), default_memtag_insert_random_tag)
7033 DEFHOOK
7034 (add_tag,
7035 "Return an RTX that represents the result of adding @var{addr_offset} to\n\
7036 the address in pointer @var{base} and @var{tag_offset} to the tag in pointer\n\
7037 @var{base}.\n\
7038 The resulting RTX must either be a valid memory address or be able to get\n\
7039 put into an operand with @code{force_operand}.\n\
7041 Unlike other memtag hooks, this must return an expression and not emit any\n\
7042 RTL.",
7043 rtx, (rtx base, poly_int64 addr_offset, uint8_t tag_offset),
7044 default_memtag_add_tag)
7046 DEFHOOK
7047 (set_tag,
7048 "Return an RTX representing @var{untagged_base} but with the tag @var{tag}.\n\
7049 Try and store this in @var{target} if convenient.\n\
7050 @var{untagged_base} is required to have a zero tag when this hook is called.\n\
7051 The default of this hook is to set the top byte of @var{untagged_base} to\n\
7052 @var{tag}.",
7053 rtx, (rtx untagged_base, rtx tag, rtx target), default_memtag_set_tag)
7055 DEFHOOK
7056 (extract_tag,
7057 "Return an RTX representing the tag stored in @var{tagged_pointer}.\n\
7058 Store the result in @var{target} if it is convenient.\n\
7059 The default represents the top byte of the original pointer.",
7060 rtx, (rtx tagged_pointer, rtx target), default_memtag_extract_tag)
7062 DEFHOOK
7063 (untagged_pointer,
7064 "Return an RTX representing @var{tagged_pointer} with its tag set to zero.\n\
7065 Store the result in @var{target} if convenient.\n\
7066 The default clears the top byte of the original pointer.",
7067 rtx, (rtx tagged_pointer, rtx target), default_memtag_untagged_pointer)
7069 HOOK_VECTOR_END (memtag)
7070 #undef HOOK_PREFIX
7071 #define HOOK_PREFIX "TARGET_"
7073 #define DEF_TARGET_INSN(NAME, PROTO) \
7074 DEFHOOK_UNDOC (have_##NAME, "", bool, (void), false)
7075 #include "target-insns.def"
7076 #undef DEF_TARGET_INSN
7078 #define DEF_TARGET_INSN(NAME, PROTO) \
7079 DEFHOOK_UNDOC (gen_##NAME, "", rtx_insn *, PROTO, NULL)
7080 #include "target-insns.def"
7081 #undef DEF_TARGET_INSN
7083 #define DEF_TARGET_INSN(NAME, PROTO) \
7084 DEFHOOKPOD (code_for_##NAME, "*", enum insn_code, CODE_FOR_nothing)
7085 #include "target-insns.def"
7086 #undef DEF_TARGET_INSN
7088 DEFHOOK
7089 (run_target_selftests,
7090 "If selftests are enabled, run any selftests for this target.",
7091 void, (void),
7092 NULL)
7094 DEFHOOK
7095 (gcov_type_size,
7096 "Returns the gcov type size in bits. This type is used for example for\n\
7097 counters incremented by profiling and code-coverage events. The default\n\
7098 value is 64, if the type size of long long is greater than 32, otherwise the\n\
7099 default value is 32. A 64-bit type is recommended to avoid overflows of the\n\
7100 counters. If the @option{-fprofile-update=atomic} is used, then the\n\
7101 counters are incremented using atomic operations. Targets not supporting\n\
7102 64-bit atomic operations may override the default value and request a 32-bit\n\
7103 type.",
7104 HOST_WIDE_INT, (void), default_gcov_type_size)
7106 /* This value represents whether the shadow call stack is implemented on
7107 the target platform. */
7108 DEFHOOKPOD
7109 (have_shadow_call_stack,
7110 "This value is true if the target platform supports\n\
7111 @option{-fsanitize=shadow-call-stack}. The default value is false.",
7112 bool, false)
7114 /* Close the 'struct gcc_target' definition. */
7115 HOOK_VECTOR_END (C90_EMPTY_HACK)