RISC-V: Add support for riscv-*-*.
[official-gcc.git] / gcc / target.def
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1 /* Target hook definitions.
2 Copyright (C) 2001-2018 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_SI_OP\n\
49 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_DI_OP\n\
50 @deftypevrx {Target Hook} {const char *} TARGET_ASM_ALIGNED_TI_OP\n\
51 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_HI_OP\n\
52 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_SI_OP\n\
53 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_DI_OP\n\
54 @deftypevrx {Target Hook} {const char *} TARGET_ASM_UNALIGNED_TI_OP\n\
55 These hooks specify assembly directives for creating certain kinds\n\
56 of integer object. The @code{TARGET_ASM_BYTE_OP} directive creates a\n\
57 byte-sized object, the @code{TARGET_ASM_ALIGNED_HI_OP} one creates an\n\
58 aligned two-byte object, and so on. Any of the hooks may be\n\
59 @code{NULL}, indicating that no suitable directive is available.\n\
60 \n\
61 The compiler will print these strings at the start of a new line,\n\
62 followed immediately by the object's initial value. In most cases,\n\
63 the string should contain a tab, a pseudo-op, and then another tab.",
64 const char *, "\t.byte\t")
65 DEFHOOKPOD (aligned_op, "*", struct asm_int_op, TARGET_ASM_ALIGNED_INT_OP)
66 DEFHOOKPOD (unaligned_op, "*", struct asm_int_op, TARGET_ASM_UNALIGNED_INT_OP)
68 /* The maximum number of bytes to skip when applying
69 LABEL_ALIGN_AFTER_BARRIER. */
70 DEFHOOK
71 (label_align_after_barrier_max_skip,
72 "The maximum number of bytes to skip before @var{label} when applying\n\
73 @code{LABEL_ALIGN_AFTER_BARRIER}. This works only if\n\
74 @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.",
75 int, (rtx_insn *label),
76 default_label_align_after_barrier_max_skip)
78 /* The maximum number of bytes to skip when applying
79 LOOP_ALIGN. */
80 DEFHOOK
81 (loop_align_max_skip,
82 "The maximum number of bytes to skip when applying @code{LOOP_ALIGN} to\n\
83 @var{label}. This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is\n\
84 defined.",
85 int, (rtx_insn *label),
86 default_loop_align_max_skip)
88 /* The maximum number of bytes to skip when applying
89 LABEL_ALIGN. */
90 DEFHOOK
91 (label_align_max_skip,
92 "The maximum number of bytes to skip when applying @code{LABEL_ALIGN}\n\
93 to @var{label}. This works only if @code{ASM_OUTPUT_MAX_SKIP_ALIGN}\n\
94 is defined.",
95 int, (rtx_insn *label),
96 default_label_align_max_skip)
98 /* The maximum number of bytes to skip when applying
99 JUMP_ALIGN. */
100 DEFHOOK
101 (jump_align_max_skip,
102 "The maximum number of bytes to skip before @var{label} when applying\n\
103 @code{JUMP_ALIGN}. This works only if\n\
104 @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.",
105 int, (rtx_insn *label),
106 default_jump_align_max_skip)
108 /* Try to output the assembler code for an integer object whose
109 value is given by X. SIZE is the size of the object in bytes and
110 ALIGNED_P indicates whether it is aligned. Return true if
111 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
112 and UNALIGNED_OP are NULL. */
113 DEFHOOK
114 (integer,
115 "The @code{assemble_integer} function uses this hook to output an\n\
116 integer object. @var{x} is the object's value, @var{size} is its size\n\
117 in bytes and @var{aligned_p} indicates whether it is aligned. The\n\
118 function should return @code{true} if it was able to output the\n\
119 object. If it returns false, @code{assemble_integer} will try to\n\
120 split the object into smaller parts.\n\
122 The default implementation of this hook will use the\n\
123 @code{TARGET_ASM_BYTE_OP} family of strings, returning @code{false}\n\
124 when the relevant string is @code{NULL}.",
125 /* Only handles cases for which BYTE_OP, ALIGNED_OP and UNALIGNED_OP are
126 NULL. */
127 bool, (rtx x, unsigned int size, int aligned_p),
128 default_assemble_integer)
130 /* Notify the backend that we have completed emitting the data for a
131 decl. */
132 DEFHOOK
133 (decl_end,
134 "Define this hook if the target assembler requires a special marker to\n\
135 terminate an initialized variable declaration.",
136 void, (void),
137 hook_void_void)
139 /* Output code that will globalize a label. */
140 DEFHOOK
141 (globalize_label,
142 "This target hook is a function to output to the stdio stream\n\
143 @var{stream} some commands that will make the label @var{name} global;\n\
144 that is, available for reference from other files.\n\
146 The default implementation relies on a proper definition of\n\
147 @code{GLOBAL_ASM_OP}.",
148 void, (FILE *stream, const char *name),
149 default_globalize_label)
151 /* Output code that will globalize a declaration. */
152 DEFHOOK
153 (globalize_decl_name,
154 "This target hook is a function to output to the stdio stream\n\
155 @var{stream} some commands that will make the name associated with @var{decl}\n\
156 global; that is, available for reference from other files.\n\
158 The default implementation uses the TARGET_ASM_GLOBALIZE_LABEL target hook.",
159 void, (FILE *stream, tree decl), default_globalize_decl_name)
161 /* Output code that will declare an external variable. */
162 DEFHOOK
163 (assemble_undefined_decl,
164 "This target hook is a function to output to the stdio stream\n\
165 @var{stream} some commands that will declare the name associated with\n\
166 @var{decl} which is not defined in the current translation unit. Most\n\
167 assemblers do not require anything to be output in this case.",
168 void, (FILE *stream, const char *name, const_tree decl),
169 hook_void_FILEptr_constcharptr_const_tree)
171 /* Output code that will emit a label for unwind info, if this
172 target requires such labels. Second argument is the decl the
173 unwind info is associated with, third is a boolean: true if
174 this is for exception handling, fourth is a boolean: true if
175 this is only a placeholder for an omitted FDE. */
176 DEFHOOK
177 (emit_unwind_label,
178 "This target hook emits a label at the beginning of each FDE@. It\n\
179 should be defined on targets where FDEs need special labels, and it\n\
180 should write the appropriate label, for the FDE associated with the\n\
181 function declaration @var{decl}, to the stdio stream @var{stream}.\n\
182 The third argument, @var{for_eh}, is a boolean: true if this is for an\n\
183 exception table. The fourth argument, @var{empty}, is a boolean:\n\
184 true if this is a placeholder label for an omitted FDE@.\n\
186 The default is that FDEs are not given nonlocal labels.",
187 void, (FILE *stream, tree decl, int for_eh, int empty),
188 default_emit_unwind_label)
190 /* Output code that will emit a label to divide up the exception table. */
191 DEFHOOK
192 (emit_except_table_label,
193 "This target hook emits a label at the beginning of the exception table.\n\
194 It should be defined on targets where it is desirable for the table\n\
195 to be broken up according to function.\n\
197 The default is that no label is emitted.",
198 void, (FILE *stream),
199 default_emit_except_table_label)
201 /* Emit a directive for setting the personality for the function. */
202 DEFHOOK
203 (emit_except_personality,
204 "If the target implements @code{TARGET_ASM_UNWIND_EMIT}, this hook may be\
205 used to emit a directive to install a personality hook into the unwind\
206 info. This hook should not be used if dwarf2 unwind info is used.",
207 void, (rtx personality),
208 NULL)
210 /* Emit any directives required to unwind this instruction. */
211 DEFHOOK
212 (unwind_emit,
213 "This target hook emits assembly directives required to unwind the\n\
214 given instruction. This is only used when @code{TARGET_EXCEPT_UNWIND_INFO}\n\
215 returns @code{UI_TARGET}.",
216 void, (FILE *stream, rtx_insn *insn),
217 NULL)
219 DEFHOOKPOD
220 (unwind_emit_before_insn,
221 "True if the @code{TARGET_ASM_UNWIND_EMIT} hook should be called before\
222 the assembly for @var{insn} has been emitted, false if the hook should\
223 be called afterward.",
224 bool, true)
226 /* Generate an internal label.
227 For now this is just a wrapper for ASM_GENERATE_INTERNAL_LABEL. */
228 DEFHOOK_UNDOC
229 (generate_internal_label,
231 void, (char *buf, const char *prefix, unsigned long labelno),
232 default_generate_internal_label)
234 /* Output an internal label. */
235 DEFHOOK
236 (internal_label,
237 "A function to output to the stdio stream @var{stream} a label whose\n\
238 name is made from the string @var{prefix} and the number @var{labelno}.\n\
240 It is absolutely essential that these labels be distinct from the labels\n\
241 used for user-level functions and variables. Otherwise, certain programs\n\
242 will have name conflicts with internal labels.\n\
244 It is desirable to exclude internal labels from the symbol table of the\n\
245 object file. Most assemblers have a naming convention for labels that\n\
246 should be excluded; on many systems, the letter @samp{L} at the\n\
247 beginning of a label has this effect. You should find out what\n\
248 convention your system uses, and follow it.\n\
250 The default version of this function utilizes @code{ASM_GENERATE_INTERNAL_LABEL}.",
251 void, (FILE *stream, const char *prefix, unsigned long labelno),
252 default_internal_label)
254 /* Output label for the constant. */
255 DEFHOOK
256 (declare_constant_name,
257 "A target hook to output to the stdio stream @var{file} any text necessary\n\
258 for declaring the name @var{name} of a constant which is being defined. This\n\
259 target hook is responsible for outputting the label definition (perhaps using\n\
260 @code{assemble_label}). The argument @var{exp} is the value of the constant,\n\
261 and @var{size} is the size of the constant in bytes. The @var{name}\n\
262 will be an internal label.\n\
264 The default version of this target hook, define the @var{name} in the\n\
265 usual manner as a label (by means of @code{assemble_label}).\n\
267 You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in this target hook.",
268 void, (FILE *file, const char *name, const_tree expr, HOST_WIDE_INT size),
269 default_asm_declare_constant_name)
271 /* Emit a ttype table reference to a typeinfo object. */
272 DEFHOOK
273 (ttype,
274 "This hook is used to output a reference from a frame unwinding table to\n\
275 the type_info object identified by @var{sym}. It should return @code{true}\n\
276 if the reference was output. Returning @code{false} will cause the\n\
277 reference to be output using the normal Dwarf2 routines.",
278 bool, (rtx sym),
279 hook_bool_rtx_false)
281 /* Emit an assembler directive to set visibility for the symbol
282 associated with the tree decl. */
283 DEFHOOK
284 (assemble_visibility,
285 "This target hook is a function to output to @var{asm_out_file} some\n\
286 commands that will make the symbol(s) associated with @var{decl} have\n\
287 hidden, protected or internal visibility as specified by @var{visibility}.",
288 void, (tree decl, int visibility),
289 default_assemble_visibility)
291 DEFHOOK
292 (print_patchable_function_entry,
293 "Generate a patchable area at the function start, consisting of\n\
294 @var{patch_area_size} NOP instructions. If the target supports named\n\
295 sections and if @var{record_p} is true, insert a pointer to the current\n\
296 location in the table of patchable functions. The default implementation\n\
297 of the hook places the table of pointers in the special section named\n\
298 @code{__patchable_function_entries}.",
299 void, (FILE *file, unsigned HOST_WIDE_INT patch_area_size, bool record_p),
300 default_print_patchable_function_entry)
302 /* Output the assembler code for entry to a function. */
303 DEFHOOK
304 (function_prologue,
305 "If defined, a function that outputs the assembler code for entry to a\n\
306 function. The prologue is responsible for setting up the stack frame,\n\
307 initializing the frame pointer register, saving registers that must be\n\
308 saved, and allocating @var{size} additional bytes of storage for the\n\
309 local variables. @var{file} is a stdio stream to which the assembler\n\
310 code should be output.\n\
312 The label for the beginning of the function need not be output by this\n\
313 macro. That has already been done when the macro is run.\n\
315 @findex regs_ever_live\n\
316 To determine which registers to save, the macro can refer to the array\n\
317 @code{regs_ever_live}: element @var{r} is nonzero if hard register\n\
318 @var{r} is used anywhere within the function. This implies the function\n\
319 prologue should save register @var{r}, provided it is not one of the\n\
320 call-used registers. (@code{TARGET_ASM_FUNCTION_EPILOGUE} must likewise use\n\
321 @code{regs_ever_live}.)\n\
323 On machines that have ``register windows'', the function entry code does\n\
324 not save on the stack the registers that are in the windows, even if\n\
325 they are supposed to be preserved by function calls; instead it takes\n\
326 appropriate steps to ``push'' the register stack, if any non-call-used\n\
327 registers are used in the function.\n\
329 @findex frame_pointer_needed\n\
330 On machines where functions may or may not have frame-pointers, the\n\
331 function entry code must vary accordingly; it must set up the frame\n\
332 pointer if one is wanted, and not otherwise. To determine whether a\n\
333 frame pointer is in wanted, the macro can refer to the variable\n\
334 @code{frame_pointer_needed}. The variable's value will be 1 at run\n\
335 time in a function that needs a frame pointer. @xref{Elimination}.\n\
337 The function entry code is responsible for allocating any stack space\n\
338 required for the function. This stack space consists of the regions\n\
339 listed below. In most cases, these regions are allocated in the\n\
340 order listed, with the last listed region closest to the top of the\n\
341 stack (the lowest address if @code{STACK_GROWS_DOWNWARD} is defined, and\n\
342 the highest address if it is not defined). You can use a different order\n\
343 for a machine if doing so is more convenient or required for\n\
344 compatibility reasons. Except in cases where required by standard\n\
345 or by a debugger, there is no reason why the stack layout used by GCC\n\
346 need agree with that used by other compilers for a machine.",
347 void, (FILE *file),
348 default_function_pro_epilogue)
350 /* Output the assembler code for end of prologue. */
351 DEFHOOK
352 (function_end_prologue,
353 "If defined, a function that outputs assembler code at the end of a\n\
354 prologue. This should be used when the function prologue is being\n\
355 emitted as RTL, and you have some extra assembler that needs to be\n\
356 emitted. @xref{prologue instruction pattern}.",
357 void, (FILE *file),
358 no_asm_to_stream)
360 /* Output the assembler code for start of epilogue. */
361 DEFHOOK
362 (function_begin_epilogue,
363 "If defined, a function that outputs assembler code at the start of an\n\
364 epilogue. This should be used when the function epilogue is being\n\
365 emitted as RTL, and you have some extra assembler that needs to be\n\
366 emitted. @xref{epilogue instruction pattern}.",
367 void, (FILE *file),
368 no_asm_to_stream)
370 /* Output the assembler code for function exit. */
371 DEFHOOK
372 (function_epilogue,
373 "If defined, a function that outputs the assembler code for exit from a\n\
374 function. The epilogue is responsible for restoring the saved\n\
375 registers and stack pointer to their values when the function was\n\
376 called, and returning control to the caller. This macro takes the\n\
377 same argument as the macro @code{TARGET_ASM_FUNCTION_PROLOGUE}, and the\n\
378 registers to restore are determined from @code{regs_ever_live} and\n\
379 @code{CALL_USED_REGISTERS} in the same way.\n\
381 On some machines, there is a single instruction that does all the work\n\
382 of returning from the function. On these machines, give that\n\
383 instruction the name @samp{return} and do not define the macro\n\
384 @code{TARGET_ASM_FUNCTION_EPILOGUE} at all.\n\
386 Do not define a pattern named @samp{return} if you want the\n\
387 @code{TARGET_ASM_FUNCTION_EPILOGUE} to be used. If you want the target\n\
388 switches to control whether return instructions or epilogues are used,\n\
389 define a @samp{return} pattern with a validity condition that tests the\n\
390 target switches appropriately. If the @samp{return} pattern's validity\n\
391 condition is false, epilogues will be used.\n\
393 On machines where functions may or may not have frame-pointers, the\n\
394 function exit code must vary accordingly. Sometimes the code for these\n\
395 two cases is completely different. To determine whether a frame pointer\n\
396 is wanted, the macro can refer to the variable\n\
397 @code{frame_pointer_needed}. The variable's value will be 1 when compiling\n\
398 a function that needs a frame pointer.\n\
400 Normally, @code{TARGET_ASM_FUNCTION_PROLOGUE} and\n\
401 @code{TARGET_ASM_FUNCTION_EPILOGUE} must treat leaf functions specially.\n\
402 The C variable @code{current_function_is_leaf} is nonzero for such a\n\
403 function. @xref{Leaf Functions}.\n\
405 On some machines, some functions pop their arguments on exit while\n\
406 others leave that for the caller to do. For example, the 68020 when\n\
407 given @option{-mrtd} pops arguments in functions that take a fixed\n\
408 number of arguments.\n\
410 @findex pops_args\n\
411 @findex crtl->args.pops_args\n\
412 Your definition of the macro @code{RETURN_POPS_ARGS} decides which\n\
413 functions pop their own arguments. @code{TARGET_ASM_FUNCTION_EPILOGUE}\n\
414 needs to know what was decided. The number of bytes of the current\n\
415 function's arguments that this function should pop is available in\n\
416 @code{crtl->args.pops_args}. @xref{Scalar Return}.",
417 void, (FILE *file),
418 default_function_pro_epilogue)
420 /* Initialize target-specific sections. */
421 DEFHOOK
422 (init_sections,
423 "Define this hook if you need to do something special to set up the\n\
424 @file{varasm.c} sections, or if your target has some special sections\n\
425 of its own that you need to create.\n\
427 GCC calls this hook after processing the command line, but before writing\n\
428 any assembly code, and before calling any of the section-returning hooks\n\
429 described below.",
430 void, (void),
431 hook_void_void)
433 /* Tell assembler to change to section NAME with attributes FLAGS.
434 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
435 which this section is associated. */
436 DEFHOOK
437 (named_section,
438 "Output assembly directives to switch to section @var{name}. The section\n\
439 should have attributes as specified by @var{flags}, which is a bit mask\n\
440 of the @code{SECTION_*} flags defined in @file{output.h}. If @var{decl}\n\
441 is non-NULL, it is the @code{VAR_DECL} or @code{FUNCTION_DECL} with which\n\
442 this section is associated.",
443 void, (const char *name, unsigned int flags, tree decl),
444 default_no_named_section)
446 /* Tell assembler what section attributes to assign this elf section
447 declaration, using their numerical value. */
448 DEFHOOK
449 (elf_flags_numeric,
450 "This hook can be used to encode ELF section flags for which no letter\n\
451 code has been defined in the assembler. It is called by\n\
452 @code{default_asm_named_section} whenever the section flags need to be\n\
453 emitted in the assembler output. If the hook returns true, then the\n\
454 numerical value for ELF section flags should be calculated from\n\
455 @var{flags} and saved in @var{*num}; the value is printed out instead of the\n\
456 normal sequence of letter codes. If the hook is not defined, or if it\n\
457 returns false, then @var{num} is ignored and the traditional letter sequence\n\
458 is emitted.",
459 bool, (unsigned int flags, unsigned int *num),
460 hook_bool_uint_uintp_false)
462 /* Return preferred text (sub)section for function DECL.
463 Main purpose of this function is to separate cold, normal and hot
464 functions. STARTUP is true when function is known to be used only
465 at startup (from static constructors or it is main()).
466 EXIT is true when function is known to be used only at exit
467 (from static destructors).
468 Return NULL if function should go to default text section. */
469 DEFHOOK
470 (function_section,
471 "Return preferred text (sub)section for function @var{decl}.\n\
472 Main purpose of this function is to separate cold, normal and hot\n\
473 functions. @var{startup} is true when function is known to be used only\n\
474 at startup (from static constructors or it is @code{main()}).\n\
475 @var{exit} is true when function is known to be used only at exit\n\
476 (from static destructors).\n\
477 Return NULL if function should go to default text section.",
478 section *, (tree decl, enum node_frequency freq, bool startup, bool exit),
479 default_function_section)
481 /* Output the assembler code for function exit. */
482 DEFHOOK
483 (function_switched_text_sections,
484 "Used by the target to emit any assembler directives or additional\
485 labels needed when a function is partitioned between different\
486 sections. Output should be written to @var{file}. The function\
487 decl is available as @var{decl} and the new section is `cold' if\
488 @var{new_is_cold} is @code{true}.",
489 void, (FILE *file, tree decl, bool new_is_cold),
490 default_function_switched_text_sections)
492 /* Return a mask describing how relocations should be treated when
493 selecting sections. Bit 1 should be set if global relocations
494 should be placed in a read-write section; bit 0 should be set if
495 local relocations should be placed in a read-write section. */
496 DEFHOOK
497 (reloc_rw_mask,
498 "Return a mask describing how relocations should be treated when\n\
499 selecting sections. Bit 1 should be set if global relocations\n\
500 should be placed in a read-write section; bit 0 should be set if\n\
501 local relocations should be placed in a read-write section.\n\
503 The default version of this function returns 3 when @option{-fpic}\n\
504 is in effect, and 0 otherwise. The hook is typically redefined\n\
505 when the target cannot support (some kinds of) dynamic relocations\n\
506 in read-only sections even in executables.",
507 int, (void),
508 default_reloc_rw_mask)
510 /* Return a flag for either generating ADDR_DIF_VEC table
511 or ADDR_VEC table for jumps in case of -fPIC/-fPIE. */
512 DEFHOOK
513 (generate_pic_addr_diff_vec,
514 "Return true to generate ADDR_DIF_VEC table\n\
515 or false to generate ADDR_VEC table for jumps in case of -fPIC.\n\
517 The default version of this function returns true if flag_pic\n\
518 equals true and false otherwise",
519 bool, (void),
520 default_generate_pic_addr_diff_vec)
522 /* Return a section for EXP. It may be a DECL or a constant. RELOC
523 is nonzero if runtime relocations must be applied; bit 1 will be
524 set if the runtime relocations require non-local name resolution.
525 ALIGN is the required alignment of the data. */
526 DEFHOOK
527 (select_section,
528 "Return the section into which @var{exp} should be placed. You can\n\
529 assume that @var{exp} is either a @code{VAR_DECL} node or a constant of\n\
530 some sort. @var{reloc} indicates whether the initial value of @var{exp}\n\
531 requires link-time relocations. Bit 0 is set when variable contains\n\
532 local relocations only, while bit 1 is set for global relocations.\n\
533 @var{align} is the constant alignment in bits.\n\
535 The default version of this function takes care of putting read-only\n\
536 variables in @code{readonly_data_section}.\n\
538 See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}.",
539 section *, (tree exp, int reloc, unsigned HOST_WIDE_INT align),
540 default_select_section)
542 /* Return a section for X. MODE is X's mode and ALIGN is its
543 alignment in bits. */
544 DEFHOOK
545 (select_rtx_section,
546 "Return the section into which a constant @var{x}, of mode @var{mode},\n\
547 should be placed. You can assume that @var{x} is some kind of\n\
548 constant in RTL@. The argument @var{mode} is redundant except in the\n\
549 case of a @code{const_int} rtx. @var{align} is the constant alignment\n\
550 in bits.\n\
552 The default version of this function takes care of putting symbolic\n\
553 constants in @code{flag_pic} mode in @code{data_section} and everything\n\
554 else in @code{readonly_data_section}.",
555 section *, (machine_mode mode, rtx x, unsigned HOST_WIDE_INT align),
556 default_select_rtx_section)
558 /* Select a unique section name for DECL. RELOC is the same as
559 for SELECT_SECTION. */
560 DEFHOOK
561 (unique_section,
562 "Build up a unique section name, expressed as a @code{STRING_CST} node,\n\
563 and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.\n\
564 As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether\n\
565 the initial value of @var{exp} requires link-time relocations.\n\
567 The default version of this function appends the symbol name to the\n\
568 ELF section name that would normally be used for the symbol. For\n\
569 example, the function @code{foo} would be placed in @code{.text.foo}.\n\
570 Whatever the actual target object format, this is often good enough.",
571 void, (tree decl, int reloc),
572 default_unique_section)
574 /* Return the readonly data section associated with function DECL. */
575 DEFHOOK
576 (function_rodata_section,
577 "Return the readonly data section associated with\n\
578 @samp{DECL_SECTION_NAME (@var{decl})}.\n\
579 The default version of this function selects @code{.gnu.linkonce.r.name} if\n\
580 the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name}\n\
581 if function is in @code{.text.name}, and the normal readonly-data section\n\
582 otherwise.",
583 section *, (tree decl),
584 default_function_rodata_section)
586 /* Nonnull if the target wants to override the default ".rodata" prefix
587 for mergeable data sections. */
588 DEFHOOKPOD
589 (mergeable_rodata_prefix,
590 "Usually, the compiler uses the prefix @code{\".rodata\"} to construct\n\
591 section names for mergeable constant data. Define this macro to override\n\
592 the string if a different section name should be used.",
593 const char *, ".rodata")
595 /* Return the section to be used for transactional memory clone tables. */
596 DEFHOOK
597 (tm_clone_table_section,
598 "Return the section that should be used for transactional memory clone\
599 tables.",
600 section *, (void), default_clone_table_section)
602 /* Output a constructor for a symbol with a given priority. */
603 DEFHOOK
604 (constructor,
605 "If defined, a function that outputs assembler code to arrange to call\n\
606 the function referenced by @var{symbol} at initialization time.\n\
608 Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking\n\
609 no arguments and with no return value. If the target supports initialization\n\
610 priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY};\n\
611 otherwise it must be @code{DEFAULT_INIT_PRIORITY}.\n\
613 If this macro is not defined by the target, a suitable default will\n\
614 be chosen if (1) the target supports arbitrary section names, (2) the\n\
615 target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2}\n\
616 is not defined.",
617 void, (rtx symbol, int priority), NULL)
619 /* Output a destructor for a symbol with a given priority. */
620 DEFHOOK
621 (destructor,
622 "This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination\n\
623 functions rather than initialization functions.",
624 void, (rtx symbol, int priority), NULL)
626 /* Output the assembler code for a thunk function. THUNK_DECL is the
627 declaration for the thunk function itself, FUNCTION is the decl for
628 the target function. DELTA is an immediate constant offset to be
629 added to THIS. If VCALL_OFFSET is nonzero, the word at
630 *(*this + vcall_offset) should be added to THIS. */
631 DEFHOOK
632 (output_mi_thunk,
633 "A function that outputs the assembler code for a thunk\n\
634 function, used to implement C++ virtual function calls with multiple\n\
635 inheritance. The thunk acts as a wrapper around a virtual function,\n\
636 adjusting the implicit object parameter before handing control off to\n\
637 the real function.\n\
639 First, emit code to add the integer @var{delta} to the location that\n\
640 contains the incoming first argument. Assume that this argument\n\
641 contains a pointer, and is the one used to pass the @code{this} pointer\n\
642 in C++. This is the incoming argument @emph{before} the function prologue,\n\
643 e.g.@: @samp{%o0} on a sparc. The addition must preserve the values of\n\
644 all other incoming arguments.\n\
646 Then, if @var{vcall_offset} is nonzero, an additional adjustment should be\n\
647 made after adding @code{delta}. In particular, if @var{p} is the\n\
648 adjusted pointer, the following adjustment should be made:\n\
650 @smallexample\n\
651 p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]\n\
652 @end smallexample\n\
654 After the additions, emit code to jump to @var{function}, which is a\n\
655 @code{FUNCTION_DECL}. This is a direct pure jump, not a call, and does\n\
656 not touch the return address. Hence returning from @var{FUNCTION} will\n\
657 return to whoever called the current @samp{thunk}.\n\
659 The effect must be as if @var{function} had been called directly with\n\
660 the adjusted first argument. This macro is responsible for emitting all\n\
661 of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE}\n\
662 and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked.\n\
664 The @var{thunk_fndecl} is redundant. (@var{delta} and @var{function}\n\
665 have already been extracted from it.) It might possibly be useful on\n\
666 some targets, but probably not.\n\
668 If you do not define this macro, the target-independent code in the C++\n\
669 front end will generate a less efficient heavyweight thunk that calls\n\
670 @var{function} instead of jumping to it. The generic approach does\n\
671 not support varargs.",
672 void, (FILE *file, tree thunk_fndecl, HOST_WIDE_INT delta,
673 HOST_WIDE_INT vcall_offset, tree function),
674 NULL)
676 /* Determine whether output_mi_thunk would succeed. */
677 /* ??? Ideally, this hook would not exist, and success or failure
678 would be returned from output_mi_thunk directly. But there's
679 too much undo-able setup involved in invoking output_mi_thunk.
680 Could be fixed by making output_mi_thunk emit rtl instead of
681 text to the output file. */
682 DEFHOOK
683 (can_output_mi_thunk,
684 "A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able\n\
685 to output the assembler code for the thunk function specified by the\n\
686 arguments it is passed, and false otherwise. In the latter case, the\n\
687 generic approach will be used by the C++ front end, with the limitations\n\
688 previously exposed.",
689 bool, (const_tree thunk_fndecl, HOST_WIDE_INT delta,
690 HOST_WIDE_INT vcall_offset, const_tree function),
691 hook_bool_const_tree_hwi_hwi_const_tree_false)
693 /* Output any boilerplate text needed at the beginning of a
694 translation unit. */
695 DEFHOOK
696 (file_start,
697 "Output to @code{asm_out_file} any text which the assembler expects to\n\
698 find at the beginning of a file. The default behavior is controlled\n\
699 by two flags, documented below. Unless your target's assembler is\n\
700 quite unusual, if you override the default, you should call\n\
701 @code{default_file_start} at some point in your target hook. This\n\
702 lets other target files rely on these variables.",
703 void, (void),
704 default_file_start)
706 /* Output any boilerplate text needed at the end of a translation unit. */
707 DEFHOOK
708 (file_end,
709 "Output to @code{asm_out_file} any text which the assembler expects\n\
710 to find at the end of a file. The default is to output nothing.",
711 void, (void),
712 hook_void_void)
714 /* Output any boilerplate text needed at the beginning of an
715 LTO output stream. */
716 DEFHOOK
717 (lto_start,
718 "Output to @code{asm_out_file} any text which the assembler expects\n\
719 to find at the start of an LTO section. The default is to output\n\
720 nothing.",
721 void, (void),
722 hook_void_void)
724 /* Output any boilerplate text needed at the end of an
725 LTO output stream. */
726 DEFHOOK
727 (lto_end,
728 "Output to @code{asm_out_file} any text which the assembler expects\n\
729 to find at the end of an LTO section. The default is to output\n\
730 nothing.",
731 void, (void),
732 hook_void_void)
734 /* Output any boilerplace text needed at the end of a
735 translation unit before debug and unwind info is emitted. */
736 DEFHOOK
737 (code_end,
738 "Output to @code{asm_out_file} any text which is needed before emitting\n\
739 unwind info and debug info at the end of a file. Some targets emit\n\
740 here PIC setup thunks that cannot be emitted at the end of file,\n\
741 because they couldn't have unwind info then. The default is to output\n\
742 nothing.",
743 void, (void),
744 hook_void_void)
746 /* Output an assembler pseudo-op to declare a library function name
747 external. */
748 DEFHOOK
749 (external_libcall,
750 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
751 pseudo-op to declare a library function name external. The name of the\n\
752 library function is given by @var{symref}, which is a @code{symbol_ref}.",
753 void, (rtx symref),
754 default_external_libcall)
756 /* Output an assembler directive to mark decl live. This instructs
757 linker to not dead code strip this symbol. */
758 DEFHOOK
759 (mark_decl_preserved,
760 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
761 directive to annotate @var{symbol} as used. The Darwin target uses the\n\
762 .no_dead_code_strip directive.",
763 void, (const char *symbol),
764 hook_void_constcharptr)
766 /* Output a record of the command line switches that have been passed. */
767 DEFHOOK
768 (record_gcc_switches,
769 "Provides the target with the ability to record the gcc command line\n\
770 switches that have been passed to the compiler, and options that are\n\
771 enabled. The @var{type} argument specifies what is being recorded.\n\
772 It can take the following values:\n\
774 @table @gcctabopt\n\
775 @item SWITCH_TYPE_PASSED\n\
776 @var{text} is a command line switch that has been set by the user.\n\
778 @item SWITCH_TYPE_ENABLED\n\
779 @var{text} is an option which has been enabled. This might be as a\n\
780 direct result of a command line switch, or because it is enabled by\n\
781 default or because it has been enabled as a side effect of a different\n\
782 command line switch. For example, the @option{-O2} switch enables\n\
783 various different individual optimization passes.\n\
785 @item SWITCH_TYPE_DESCRIPTIVE\n\
786 @var{text} is either NULL or some descriptive text which should be\n\
787 ignored. If @var{text} is NULL then it is being used to warn the\n\
788 target hook that either recording is starting or ending. The first\n\
789 time @var{type} is SWITCH_TYPE_DESCRIPTIVE and @var{text} is NULL, the\n\
790 warning is for start up and the second time the warning is for\n\
791 wind down. This feature is to allow the target hook to make any\n\
792 necessary preparations before it starts to record switches and to\n\
793 perform any necessary tidying up after it has finished recording\n\
794 switches.\n\
796 @item SWITCH_TYPE_LINE_START\n\
797 This option can be ignored by this target hook.\n\
799 @item SWITCH_TYPE_LINE_END\n\
800 This option can be ignored by this target hook.\n\
801 @end table\n\
803 The hook's return value must be zero. Other return values may be\n\
804 supported in the future.\n\
806 By default this hook is set to NULL, but an example implementation is\n\
807 provided for ELF based targets. Called @var{elf_record_gcc_switches},\n\
808 it records the switches as ASCII text inside a new, string mergeable\n\
809 section in the assembler output file. The name of the new section is\n\
810 provided by the @code{TARGET_ASM_RECORD_GCC_SWITCHES_SECTION} target\n\
811 hook.",
812 int, (print_switch_type type, const char *text),
813 NULL)
815 /* The name of the section that the example ELF implementation of
816 record_gcc_switches will use to store the information. Target
817 specific versions of record_gcc_switches may or may not use
818 this information. */
819 DEFHOOKPOD
820 (record_gcc_switches_section,
821 "This is the name of the section that will be created by the example\n\
822 ELF implementation of the @code{TARGET_ASM_RECORD_GCC_SWITCHES} target\n\
823 hook.",
824 const char *, ".GCC.command.line")
826 /* Output the definition of a section anchor. */
827 DEFHOOK
828 (output_anchor,
829 "Write the assembly code to define section anchor @var{x}, which is a\n\
830 @code{SYMBOL_REF} for which @samp{SYMBOL_REF_ANCHOR_P (@var{x})} is true.\n\
831 The hook is called with the assembly output position set to the beginning\n\
832 of @code{SYMBOL_REF_BLOCK (@var{x})}.\n\
834 If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses\n\
835 it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}.\n\
836 If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition\n\
837 is @code{NULL}, which disables the use of section anchors altogether.",
838 void, (rtx x),
839 default_asm_output_anchor)
841 DEFHOOK
842 (output_ident,
843 "Output a string based on @var{name}, suitable for the @samp{#ident} \
844 directive, or the equivalent directive or pragma in non-C-family languages. \
845 If this hook is not defined, nothing is output for the @samp{#ident} \
846 directive.",
847 void, (const char *name),
848 hook_void_constcharptr)
850 /* Output a DTP-relative reference to a TLS symbol. */
851 DEFHOOK
852 (output_dwarf_dtprel,
853 "If defined, this target hook is a function which outputs a DTP-relative\n\
854 reference to the given TLS symbol of the specified size.",
855 void, (FILE *file, int size, rtx x),
856 NULL)
858 /* Some target machines need to postscan each insn after it is output. */
859 DEFHOOK
860 (final_postscan_insn,
861 "If defined, this target hook is a function which is executed just after the\n\
862 output of assembler code for @var{insn}, to change the mode of the assembler\n\
863 if necessary.\n\
865 Here the argument @var{opvec} is the vector containing the operands\n\
866 extracted from @var{insn}, and @var{noperands} is the number of\n\
867 elements of the vector which contain meaningful data for this insn.\n\
868 The contents of this vector are what was used to convert the insn\n\
869 template into assembler code, so you can change the assembler mode\n\
870 by checking the contents of the vector.",
871 void, (FILE *file, rtx_insn *insn, rtx *opvec, int noperands),
872 NULL)
874 /* Emit the trampoline template. This hook may be NULL. */
875 DEFHOOK
876 (trampoline_template,
877 "This hook is called by @code{assemble_trampoline_template} to output,\n\
878 on the stream @var{f}, assembler code for a block of data that contains\n\
879 the constant parts of a trampoline. This code should not include a\n\
880 label---the label is taken care of automatically.\n\
882 If you do not define this hook, it means no template is needed\n\
883 for the target. Do not define this hook on systems where the block move\n\
884 code to copy the trampoline into place would be larger than the code\n\
885 to generate it on the spot.",
886 void, (FILE *f),
887 NULL)
889 DEFHOOK
890 (output_source_filename,
891 "Output DWARF debugging information which indicates that filename\
892 @var{name} is the current source file to the stdio stream @var{file}.\n\
894 This target hook need not be defined if the standard form of output\
895 for the file format in use is appropriate.",
896 void ,(FILE *file, const char *name),
897 default_asm_output_source_filename)
899 DEFHOOK
900 (output_addr_const_extra,
901 "A target hook to recognize @var{rtx} patterns that @code{output_addr_const}\n\
902 can't deal with, and output assembly code to @var{file} corresponding to\n\
903 the pattern @var{x}. This may be used to allow machine-dependent\n\
904 @code{UNSPEC}s to appear within constants.\n\
906 If target hook fails to recognize a pattern, it must return @code{false},\n\
907 so that a standard error message is printed. If it prints an error message\n\
908 itself, by calling, for example, @code{output_operand_lossage}, it may just\n\
909 return @code{true}.",
910 bool, (FILE *file, rtx x),
911 hook_bool_FILEptr_rtx_false)
913 /* ??? The TARGET_PRINT_OPERAND* hooks are part of the asm_out struct,
914 even though that is not reflected in the macro name to override their
915 initializers. */
916 #undef HOOK_PREFIX
917 #define HOOK_PREFIX "TARGET_"
919 /* Emit a machine-specific insn operand. */
920 /* ??? tm.texi only documents the old macro PRINT_OPERAND,
921 not this hook, and uses a different name for the argument FILE. */
922 DEFHOOK_UNDOC
923 (print_operand,
925 void, (FILE *file, rtx x, int code),
926 default_print_operand)
928 /* Emit a machine-specific memory address. */
929 /* ??? tm.texi only documents the old macro PRINT_OPERAND_ADDRESS,
930 not this hook, and uses different argument names. */
931 DEFHOOK_UNDOC
932 (print_operand_address,
934 void, (FILE *file, machine_mode mode, rtx addr),
935 default_print_operand_address)
937 /* Determine whether CODE is a valid punctuation character for the
938 `print_operand' hook. */
939 /* ??? tm.texi only documents the old macro PRINT_OPERAND_PUNCT_VALID_P,
940 not this hook. */
941 DEFHOOK_UNDOC
942 (print_operand_punct_valid_p,
944 bool ,(unsigned char code),
945 default_print_operand_punct_valid_p)
947 /* Given a symbol name, perform same mangling as assemble_name and
948 ASM_OUTPUT_LABELREF, returning result as an IDENTIFIER_NODE. */
949 DEFHOOK
950 (mangle_assembler_name,
951 "Given a symbol @var{name}, perform same mangling as @code{varasm.c}'s\
952 @code{assemble_name}, but in memory rather than to a file stream, returning\
953 result as an @code{IDENTIFIER_NODE}. Required for correct LTO symtabs. The\
954 default implementation calls the @code{TARGET_STRIP_NAME_ENCODING} hook and\
955 then prepends the @code{USER_LABEL_PREFIX}, if any.",
956 tree, (const char *name),
957 default_mangle_assembler_name)
959 HOOK_VECTOR_END (asm_out)
961 /* Functions relating to instruction scheduling. All of these
962 default to null pointers, which haifa-sched.c looks for and handles. */
963 #undef HOOK_PREFIX
964 #define HOOK_PREFIX "TARGET_SCHED_"
965 HOOK_VECTOR (TARGET_SCHED, sched)
967 /* Given the current cost, COST, of an insn, INSN, calculate and
968 return a new cost based on its relationship to DEP_INSN through
969 the dependence LINK. The default is to make no adjustment. */
970 DEFHOOK
971 (adjust_cost,
972 "This function corrects the value of @var{cost} based on the\n\
973 relationship between @var{insn} and @var{dep_insn} through a\n\
974 dependence of type dep_type, and strength @var{dw}. It should return the new\n\
975 value. The default is to make no adjustment to @var{cost}. This can be\n\
976 used for example to specify to the scheduler using the traditional pipeline\n\
977 description that an output- or anti-dependence does not incur the same cost\n\
978 as a data-dependence. If the scheduler using the automaton based pipeline\n\
979 description, the cost of anti-dependence is zero and the cost of\n\
980 output-dependence is maximum of one and the difference of latency\n\
981 times of the first and the second insns. If these values are not\n\
982 acceptable, you could use the hook to modify them too. See also\n\
983 @pxref{Processor pipeline description}.",
984 int, (rtx_insn *insn, int dep_type1, rtx_insn *dep_insn, int cost,
985 unsigned int dw),
986 NULL)
988 /* Adjust the priority of an insn as you see fit. Returns the new priority. */
989 DEFHOOK
990 (adjust_priority,
991 "This hook adjusts the integer scheduling priority @var{priority} of\n\
992 @var{insn}. It should return the new priority. Increase the priority to\n\
993 execute @var{insn} earlier, reduce the priority to execute @var{insn}\n\
994 later. Do not define this hook if you do not need to adjust the\n\
995 scheduling priorities of insns.",
996 int, (rtx_insn *insn, int priority), NULL)
998 /* Function which returns the maximum number of insns that can be
999 scheduled in the same machine cycle. This must be constant
1000 over an entire compilation. The default is 1. */
1001 DEFHOOK
1002 (issue_rate,
1003 "This hook returns the maximum number of instructions that can ever\n\
1004 issue at the same time on the target machine. The default is one.\n\
1005 Although the insn scheduler can define itself the possibility of issue\n\
1006 an insn on the same cycle, the value can serve as an additional\n\
1007 constraint to issue insns on the same simulated processor cycle (see\n\
1008 hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).\n\
1009 This value must be constant over the entire compilation. If you need\n\
1010 it to vary depending on what the instructions are, you must use\n\
1011 @samp{TARGET_SCHED_VARIABLE_ISSUE}.",
1012 int, (void), NULL)
1014 /* Calculate how much this insn affects how many more insns we
1015 can emit this cycle. Default is they all cost the same. */
1016 DEFHOOK
1017 (variable_issue,
1018 "This hook is executed by the scheduler after it has scheduled an insn\n\
1019 from the ready list. It should return the number of insns which can\n\
1020 still be issued in the current cycle. The default is\n\
1021 @samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and\n\
1022 @code{USE}, which normally are not counted against the issue rate.\n\
1023 You should define this hook if some insns take more machine resources\n\
1024 than others, so that fewer insns can follow them in the same cycle.\n\
1025 @var{file} is either a null pointer, or a stdio stream to write any\n\
1026 debug output to. @var{verbose} is the verbose level provided by\n\
1027 @option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that\n\
1028 was scheduled.",
1029 int, (FILE *file, int verbose, rtx_insn *insn, int more), NULL)
1031 /* Initialize machine-dependent scheduling code. */
1032 DEFHOOK
1033 (init,
1034 "This hook is executed by the scheduler at the beginning of each block of\n\
1035 instructions that are to be scheduled. @var{file} is either a null\n\
1036 pointer, or a stdio stream to write any debug output to. @var{verbose}\n\
1037 is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1038 @var{max_ready} is the maximum number of insns in the current scheduling\n\
1039 region that can be live at the same time. This can be used to allocate\n\
1040 scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}.",
1041 void, (FILE *file, int verbose, int max_ready), NULL)
1043 /* Finalize machine-dependent scheduling code. */
1044 DEFHOOK
1045 (finish,
1046 "This hook is executed by the scheduler at the end of each block of\n\
1047 instructions that are to be scheduled. It can be used to perform\n\
1048 cleanup of any actions done by the other scheduling hooks. @var{file}\n\
1049 is either a null pointer, or a stdio stream to write any debug output\n\
1050 to. @var{verbose} is the verbose level provided by\n\
1051 @option{-fsched-verbose-@var{n}}.",
1052 void, (FILE *file, int verbose), NULL)
1054 /* Initialize machine-dependent function wide scheduling code. */
1055 DEFHOOK
1056 (init_global,
1057 "This hook is executed by the scheduler after function level initializations.\n\
1058 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1059 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1060 @var{old_max_uid} is the maximum insn uid when scheduling begins.",
1061 void, (FILE *file, int verbose, int old_max_uid), NULL)
1063 /* Finalize machine-dependent function wide scheduling code. */
1064 DEFHOOK
1065 (finish_global,
1066 "This is the cleanup hook corresponding to @code{TARGET_SCHED_INIT_GLOBAL}.\n\
1067 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1068 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.",
1069 void, (FILE *file, int verbose), NULL)
1071 /* Reorder insns in a machine-dependent fashion, in two different
1072 places. Default does nothing. */
1073 DEFHOOK
1074 (reorder,
1075 "This hook is executed by the scheduler after it has scheduled the ready\n\
1076 list, to allow the machine description to reorder it (for example to\n\
1077 combine two small instructions together on @samp{VLIW} machines).\n\
1078 @var{file} is either a null pointer, or a stdio stream to write any\n\
1079 debug output to. @var{verbose} is the verbose level provided by\n\
1080 @option{-fsched-verbose-@var{n}}. @var{ready} is a pointer to the ready\n\
1081 list of instructions that are ready to be scheduled. @var{n_readyp} is\n\
1082 a pointer to the number of elements in the ready list. The scheduler\n\
1083 reads the ready list in reverse order, starting with\n\
1084 @var{ready}[@var{*n_readyp} @minus{} 1] and going to @var{ready}[0]. @var{clock}\n\
1085 is the timer tick of the scheduler. You may modify the ready list and\n\
1086 the number of ready insns. The return value is the number of insns that\n\
1087 can issue this cycle; normally this is just @code{issue_rate}. See also\n\
1088 @samp{TARGET_SCHED_REORDER2}.",
1089 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1091 DEFHOOK
1092 (reorder2,
1093 "Like @samp{TARGET_SCHED_REORDER}, but called at a different time. That\n\
1094 function is called whenever the scheduler starts a new cycle. This one\n\
1095 is called once per iteration over a cycle, immediately after\n\
1096 @samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and\n\
1097 return the number of insns to be scheduled in the same cycle. Defining\n\
1098 this hook can be useful if there are frequent situations where\n\
1099 scheduling one insn causes other insns to become ready in the same\n\
1100 cycle. These other insns can then be taken into account properly.",
1101 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1103 DEFHOOK
1104 (macro_fusion_p,
1105 "This hook is used to check whether target platform supports macro fusion.",
1106 bool, (void), NULL)
1108 DEFHOOK
1109 (macro_fusion_pair_p,
1110 "This hook is used to check whether two insns should be macro fused for\n\
1111 a target microarchitecture. If this hook returns true for the given insn pair\n\
1112 (@var{prev} and @var{curr}), the scheduler will put them into a sched\n\
1113 group, and they will not be scheduled apart. The two insns will be either\n\
1114 two SET insns or a compare and a conditional jump and this hook should\n\
1115 validate any dependencies needed to fuse the two insns together.",
1116 bool, (rtx_insn *prev, rtx_insn *curr), NULL)
1118 /* The following member value is a pointer to a function called
1119 after evaluation forward dependencies of insns in chain given
1120 by two parameter values (head and tail correspondingly). */
1121 DEFHOOK
1122 (dependencies_evaluation_hook,
1123 "This hook is called after evaluation forward dependencies of insns in\n\
1124 chain given by two parameter values (@var{head} and @var{tail}\n\
1125 correspondingly) but before insns scheduling of the insn chain. For\n\
1126 example, it can be used for better insn classification if it requires\n\
1127 analysis of dependencies. This hook can use backward and forward\n\
1128 dependencies of the insn scheduler because they are already\n\
1129 calculated.",
1130 void, (rtx_insn *head, rtx_insn *tail), NULL)
1132 /* The values of the following four members are pointers to functions
1133 used to simplify the automaton descriptions. dfa_pre_cycle_insn and
1134 dfa_post_cycle_insn give functions returning insns which are used to
1135 change the pipeline hazard recognizer state when the new simulated
1136 processor cycle correspondingly starts and finishes. The function
1137 defined by init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are
1138 used to initialize the corresponding insns. The default values of
1139 the members result in not changing the automaton state when the
1140 new simulated processor cycle correspondingly starts and finishes. */
1142 DEFHOOK
1143 (init_dfa_pre_cycle_insn,
1144 "The hook can be used to initialize data used by the previous hook.",
1145 void, (void), NULL)
1147 DEFHOOK
1148 (dfa_pre_cycle_insn,
1149 "The hook returns an RTL insn. The automaton state used in the\n\
1150 pipeline hazard recognizer is changed as if the insn were scheduled\n\
1151 when the new simulated processor cycle starts. Usage of the hook may\n\
1152 simplify the automaton pipeline description for some @acronym{VLIW}\n\
1153 processors. If the hook is defined, it is used only for the automaton\n\
1154 based pipeline description. The default is not to change the state\n\
1155 when the new simulated processor cycle starts.",
1156 rtx, (void), NULL)
1158 DEFHOOK
1159 (init_dfa_post_cycle_insn,
1160 "The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but\n\
1161 used to initialize data used by the previous hook.",
1162 void, (void), NULL)
1164 DEFHOOK
1165 (dfa_post_cycle_insn,
1166 "The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1167 to changed the state as if the insn were scheduled when the new\n\
1168 simulated processor cycle finishes.",
1169 rtx_insn *, (void), NULL)
1171 /* The values of the following two members are pointers to
1172 functions used to simplify the automaton descriptions.
1173 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
1174 immediately before and after cycle is advanced. */
1176 DEFHOOK
1177 (dfa_pre_advance_cycle,
1178 "The hook to notify target that the current simulated cycle is about to finish.\n\
1179 The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1180 to change the state in more complicated situations - e.g., when advancing\n\
1181 state on a single insn is not enough.",
1182 void, (void), NULL)
1184 DEFHOOK
1185 (dfa_post_advance_cycle,
1186 "The hook to notify target that new simulated cycle has just started.\n\
1187 The hook is analogous to @samp{TARGET_SCHED_DFA_POST_CYCLE_INSN} but used\n\
1188 to change the state in more complicated situations - e.g., when advancing\n\
1189 state on a single insn is not enough.",
1190 void, (void), NULL)
1192 /* The following member value is a pointer to a function returning value
1193 which defines how many insns in queue `ready' will we try for
1194 multi-pass scheduling. If the member value is nonzero and the
1195 function returns positive value, the DFA based scheduler will make
1196 multi-pass scheduling for the first cycle. In other words, we will
1197 try to choose ready insn which permits to start maximum number of
1198 insns on the same cycle. */
1199 DEFHOOK
1200 (first_cycle_multipass_dfa_lookahead,
1201 "This hook controls better choosing an insn from the ready insn queue\n\
1202 for the @acronym{DFA}-based insn scheduler. Usually the scheduler\n\
1203 chooses the first insn from the queue. If the hook returns a positive\n\
1204 value, an additional scheduler code tries all permutations of\n\
1205 @samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}\n\
1206 subsequent ready insns to choose an insn whose issue will result in\n\
1207 maximal number of issued insns on the same cycle. For the\n\
1208 @acronym{VLIW} processor, the code could actually solve the problem of\n\
1209 packing simple insns into the @acronym{VLIW} insn. Of course, if the\n\
1210 rules of @acronym{VLIW} packing are described in the automaton.\n\
1212 This code also could be used for superscalar @acronym{RISC}\n\
1213 processors. Let us consider a superscalar @acronym{RISC} processor\n\
1214 with 3 pipelines. Some insns can be executed in pipelines @var{A} or\n\
1215 @var{B}, some insns can be executed only in pipelines @var{B} or\n\
1216 @var{C}, and one insn can be executed in pipeline @var{B}. The\n\
1217 processor may issue the 1st insn into @var{A} and the 2nd one into\n\
1218 @var{B}. In this case, the 3rd insn will wait for freeing @var{B}\n\
1219 until the next cycle. If the scheduler issues the 3rd insn the first,\n\
1220 the processor could issue all 3 insns per cycle.\n\
1222 Actually this code demonstrates advantages of the automaton based\n\
1223 pipeline hazard recognizer. We try quickly and easy many insn\n\
1224 schedules to choose the best one.\n\
1226 The default is no multipass scheduling.",
1227 int, (void), NULL)
1229 /* The following member value is pointer to a function controlling
1230 what insns from the ready insn queue will be considered for the
1231 multipass insn scheduling. If the hook returns zero for insn
1232 passed as the parameter, the insn will be not chosen to be issued. */
1233 DEFHOOK
1234 (first_cycle_multipass_dfa_lookahead_guard,
1235 "\n\
1236 This hook controls what insns from the ready insn queue will be\n\
1237 considered for the multipass insn scheduling. If the hook returns\n\
1238 zero for @var{insn}, the insn will be considered in multipass scheduling.\n\
1239 Positive return values will remove @var{insn} from consideration on\n\
1240 the current round of multipass scheduling.\n\
1241 Negative return values will remove @var{insn} from consideration for given\n\
1242 number of cycles.\n\
1243 Backends should be careful about returning non-zero for highest priority\n\
1244 instruction at position 0 in the ready list. @var{ready_index} is passed\n\
1245 to allow backends make correct judgements.\n\
1247 The default is that any ready insns can be chosen to be issued.",
1248 int, (rtx_insn *insn, int ready_index), NULL)
1250 /* This hook prepares the target for a new round of multipass
1251 scheduling.
1252 DATA is a pointer to target-specific data used for multipass scheduling.
1253 READY_TRY and N_READY represent the current state of search in the
1254 optimization space. The target can filter out instructions that
1255 should not be tried during current round by setting corresponding
1256 elements in READY_TRY to non-zero.
1257 FIRST_CYCLE_INSN_P is true if this is the first round of multipass
1258 scheduling on current cycle. */
1259 DEFHOOK
1260 (first_cycle_multipass_begin,
1261 "This hook prepares the target backend for a new round of multipass\n\
1262 scheduling.",
1263 void, (void *data, signed char *ready_try, int n_ready, bool first_cycle_insn_p),
1264 NULL)
1266 /* This hook is called when multipass scheduling evaluates instruction INSN.
1267 DATA is a pointer to target-specific data that can be used to record effects
1268 of INSN on CPU that are not described in DFA.
1269 READY_TRY and N_READY represent the current state of search in the
1270 optimization space. The target can filter out instructions that
1271 should not be tried after issuing INSN by setting corresponding
1272 elements in READY_TRY to non-zero.
1273 INSN is the instruction being evaluated.
1274 PREV_DATA is a pointer to target-specific data corresponding
1275 to a state before issuing INSN. */
1276 DEFHOOK
1277 (first_cycle_multipass_issue,
1278 "This hook is called when multipass scheduling evaluates instruction INSN.",
1279 void, (void *data, signed char *ready_try, int n_ready, rtx_insn *insn,
1280 const void *prev_data), NULL)
1282 /* This hook is called when multipass scheduling backtracks from evaluation of
1283 instruction corresponding to DATA.
1284 DATA is a pointer to target-specific data that stores the effects
1285 of instruction from which the algorithm backtracks on CPU that are not
1286 described in DFA.
1287 READY_TRY and N_READY represent the current state of search in the
1288 optimization space. The target can filter out instructions that
1289 should not be tried after issuing INSN by setting corresponding
1290 elements in READY_TRY to non-zero. */
1291 DEFHOOK
1292 (first_cycle_multipass_backtrack,
1293 "This is called when multipass scheduling backtracks from evaluation of\n\
1294 an instruction.",
1295 void, (const void *data, signed char *ready_try, int n_ready), NULL)
1297 /* This hook notifies the target about the result of the concluded current
1298 round of multipass scheduling.
1299 DATA is a pointer.
1300 If DATA is non-NULL it points to target-specific data used for multipass
1301 scheduling which corresponds to instruction at the start of the chain of
1302 the winning solution. DATA is NULL when multipass scheduling cannot find
1303 a good enough solution on current cycle and decides to retry later,
1304 usually after advancing the cycle count. */
1305 DEFHOOK
1306 (first_cycle_multipass_end,
1307 "This hook notifies the target about the result of the concluded current\n\
1308 round of multipass scheduling.",
1309 void, (const void *data), NULL)
1311 /* This hook is called to initialize target-specific data for multipass
1312 scheduling after it has been allocated.
1313 DATA is a pointer to target-specific data that stores the effects
1314 of instruction from which the algorithm backtracks on CPU that are not
1315 described in DFA. */
1316 DEFHOOK
1317 (first_cycle_multipass_init,
1318 "This hook initializes target-specific data used in multipass scheduling.",
1319 void, (void *data), NULL)
1321 /* This hook is called to finalize target-specific data for multipass
1322 scheduling before it is deallocated.
1323 DATA is a pointer to target-specific data that stores the effects
1324 of instruction from which the algorithm backtracks on CPU that are not
1325 described in DFA. */
1326 DEFHOOK
1327 (first_cycle_multipass_fini,
1328 "This hook finalizes target-specific data used in multipass scheduling.",
1329 void, (void *data), NULL)
1331 /* The following member value is pointer to a function called by
1332 the insn scheduler before issuing insn passed as the third
1333 parameter on given cycle. If the hook returns nonzero, the
1334 insn is not issued on given processors cycle. Instead of that,
1335 the processor cycle is advanced. If the value passed through
1336 the last parameter is zero, the insn ready queue is not sorted
1337 on the new cycle start as usually. The first parameter passes
1338 file for debugging output. The second one passes the scheduler
1339 verbose level of the debugging output. The forth and the fifth
1340 parameter values are correspondingly processor cycle on which
1341 the previous insn has been issued and the current processor cycle. */
1342 DEFHOOK
1343 (dfa_new_cycle,
1344 "This hook is called by the insn scheduler before issuing @var{insn}\n\
1345 on cycle @var{clock}. If the hook returns nonzero,\n\
1346 @var{insn} is not issued on this processor cycle. Instead,\n\
1347 the processor cycle is advanced. If *@var{sort_p}\n\
1348 is zero, the insn ready queue is not sorted on the new cycle\n\
1349 start as usually. @var{dump} and @var{verbose} specify the file and\n\
1350 verbosity level to use for debugging output.\n\
1351 @var{last_clock} and @var{clock} are, respectively, the\n\
1352 processor cycle on which the previous insn has been issued,\n\
1353 and the current processor cycle.",
1354 int, (FILE *dump, int verbose, rtx_insn *insn, int last_clock,
1355 int clock, int *sort_p),
1356 NULL)
1358 /* The following member value is a pointer to a function called by the
1359 insn scheduler. It should return true if there exists a dependence
1360 which is considered costly by the target, between the insn
1361 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
1362 the dep that represents the dependence between the two insns. The
1363 second argument is the cost of the dependence as estimated by
1364 the scheduler. The last argument is the distance in cycles
1365 between the already scheduled insn (first parameter) and the
1366 second insn (second parameter). */
1367 DEFHOOK
1368 (is_costly_dependence,
1369 "This hook is used to define which dependences are considered costly by\n\
1370 the target, so costly that it is not advisable to schedule the insns that\n\
1371 are involved in the dependence too close to one another. The parameters\n\
1372 to this hook are as follows: The first parameter @var{_dep} is the dependence\n\
1373 being evaluated. The second parameter @var{cost} is the cost of the\n\
1374 dependence as estimated by the scheduler, and the third\n\
1375 parameter @var{distance} is the distance in cycles between the two insns.\n\
1376 The hook returns @code{true} if considering the distance between the two\n\
1377 insns the dependence between them is considered costly by the target,\n\
1378 and @code{false} otherwise.\n\
1380 Defining this hook can be useful in multiple-issue out-of-order machines,\n\
1381 where (a) it's practically hopeless to predict the actual data/resource\n\
1382 delays, however: (b) there's a better chance to predict the actual grouping\n\
1383 that will be formed, and (c) correctly emulating the grouping can be very\n\
1384 important. In such targets one may want to allow issuing dependent insns\n\
1385 closer to one another---i.e., closer than the dependence distance; however,\n\
1386 not in cases of ``costly dependences'', which this hooks allows to define.",
1387 bool, (struct _dep *_dep, int cost, int distance), NULL)
1389 /* The following member value is a pointer to a function called
1390 by the insn scheduler. This hook is called to notify the backend
1391 that new instructions were emitted. */
1392 DEFHOOK
1393 (h_i_d_extended,
1394 "This hook is called by the insn scheduler after emitting a new instruction to\n\
1395 the instruction stream. The hook notifies a target backend to extend its\n\
1396 per instruction data structures.",
1397 void, (void), NULL)
1399 /* Next 5 functions are for multi-point scheduling. */
1401 /* Allocate memory for scheduler context. */
1402 DEFHOOK
1403 (alloc_sched_context,
1404 "Return a pointer to a store large enough to hold target scheduling context.",
1405 void *, (void), NULL)
1407 /* Fills the context from the local machine scheduler context. */
1408 DEFHOOK
1409 (init_sched_context,
1410 "Initialize store pointed to by @var{tc} to hold target scheduling context.\n\
1411 It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the\n\
1412 beginning of the block. Otherwise, copy the current context into @var{tc}.",
1413 void, (void *tc, bool clean_p), NULL)
1415 /* Sets local machine scheduler context to a saved value. */
1416 DEFHOOK
1417 (set_sched_context,
1418 "Copy target scheduling context pointed to by @var{tc} to the current context.",
1419 void, (void *tc), NULL)
1421 /* Clears a scheduler context so it becomes like after init. */
1422 DEFHOOK
1423 (clear_sched_context,
1424 "Deallocate internal data in target scheduling context pointed to by @var{tc}.",
1425 void, (void *tc), NULL)
1427 /* Frees the scheduler context. */
1428 DEFHOOK
1429 (free_sched_context,
1430 "Deallocate a store for target scheduling context pointed to by @var{tc}.",
1431 void, (void *tc), NULL)
1433 /* The following member value is a pointer to a function called
1434 by the insn scheduler.
1435 The first parameter is an instruction, the second parameter is the type
1436 of the requested speculation, and the third parameter is a pointer to the
1437 speculative pattern of the corresponding type (set if return value == 1).
1438 It should return
1439 -1, if there is no pattern, that will satisfy the requested speculation type,
1440 0, if current pattern satisfies the requested speculation type,
1441 1, if pattern of the instruction should be changed to the newly
1442 generated one. */
1443 DEFHOOK
1444 (speculate_insn,
1445 "This hook is called by the insn scheduler when @var{insn} has only\n\
1446 speculative dependencies and therefore can be scheduled speculatively.\n\
1447 The hook is used to check if the pattern of @var{insn} has a speculative\n\
1448 version and, in case of successful check, to generate that speculative\n\
1449 pattern. The hook should return 1, if the instruction has a speculative form,\n\
1450 or @minus{}1, if it doesn't. @var{request} describes the type of requested\n\
1451 speculation. If the return value equals 1 then @var{new_pat} is assigned\n\
1452 the generated speculative pattern.",
1453 int, (rtx_insn *insn, unsigned int dep_status, rtx *new_pat), NULL)
1455 /* The following member value is a pointer to a function called
1456 by the insn scheduler. It should return true if the check instruction
1457 passed as the parameter needs a recovery block. */
1458 DEFHOOK
1459 (needs_block_p,
1460 "This hook is called by the insn scheduler during generation of recovery code\n\
1461 for @var{insn}. It should return @code{true}, if the corresponding check\n\
1462 instruction should branch to recovery code, or @code{false} otherwise.",
1463 bool, (unsigned int dep_status), NULL)
1465 /* The following member value is a pointer to a function called
1466 by the insn scheduler. It should return a pattern for the check
1467 instruction.
1468 The first parameter is a speculative instruction, the second parameter
1469 is the label of the corresponding recovery block (or null, if it is a
1470 simple check). The third parameter is the kind of speculation that
1471 is being performed. */
1472 DEFHOOK
1473 (gen_spec_check,
1474 "This hook is called by the insn scheduler to generate a pattern for recovery\n\
1475 check instruction. If @var{mutate_p} is zero, then @var{insn} is a\n\
1476 speculative instruction for which the check should be generated.\n\
1477 @var{label} is either a label of a basic block, where recovery code should\n\
1478 be emitted, or a null pointer, when requested check doesn't branch to\n\
1479 recovery code (a simple check). If @var{mutate_p} is nonzero, then\n\
1480 a pattern for a branchy check corresponding to a simple check denoted by\n\
1481 @var{insn} should be generated. In this case @var{label} can't be null.",
1482 rtx, (rtx_insn *insn, rtx_insn *label, unsigned int ds), NULL)
1484 /* The following member value is a pointer to a function that provides
1485 information about the speculation capabilities of the target.
1486 The parameter is a pointer to spec_info variable. */
1487 DEFHOOK
1488 (set_sched_flags,
1489 "This hook is used by the insn scheduler to find out what features should be\n\
1490 enabled/used.\n\
1491 The structure *@var{spec_info} should be filled in by the target.\n\
1492 The structure describes speculation types that can be used in the scheduler.",
1493 void, (struct spec_info_def *spec_info), NULL)
1495 DEFHOOK_UNDOC
1496 (get_insn_spec_ds,
1497 "Return speculation types of instruction @var{insn}.",
1498 unsigned int, (rtx_insn *insn), NULL)
1500 DEFHOOK_UNDOC
1501 (get_insn_checked_ds,
1502 "Return speculation types that are checked for instruction @var{insn}",
1503 unsigned int, (rtx_insn *insn), NULL)
1505 DEFHOOK
1506 (can_speculate_insn,
1507 "Some instructions should never be speculated by the schedulers, usually\n\
1508 because the instruction is too expensive to get this wrong. Often such\n\
1509 instructions have long latency, and often they are not fully modeled in the\n\
1510 pipeline descriptions. This hook should return @code{false} if @var{insn}\n\
1511 should not be speculated.",
1512 bool, (rtx_insn *insn), hook_bool_rtx_insn_true)
1514 DEFHOOK_UNDOC
1515 (skip_rtx_p,
1516 "Return bool if rtx scanning should just skip current layer and\
1517 advance to the inner rtxes.",
1518 bool, (const_rtx x), NULL)
1520 /* The following member value is a pointer to a function that provides
1521 information about the target resource-based lower bound which is
1522 used by the swing modulo scheduler. The parameter is a pointer
1523 to ddg variable. */
1524 DEFHOOK
1525 (sms_res_mii,
1526 "This hook is called by the swing modulo scheduler to calculate a\n\
1527 resource-based lower bound which is based on the resources available in\n\
1528 the machine and the resources required by each instruction. The target\n\
1529 backend can use @var{g} to calculate such bound. A very simple lower\n\
1530 bound will be used in case this hook is not implemented: the total number\n\
1531 of instructions divided by the issue rate.",
1532 int, (struct ddg *g), NULL)
1534 /* The following member value is a function that initializes dispatch
1535 schedling and adds instructions to dispatch window according to its
1536 parameters. */
1537 DEFHOOK
1538 (dispatch_do,
1539 "This hook is called by Haifa Scheduler. It performs the operation specified\n\
1540 in its second parameter.",
1541 void, (rtx_insn *insn, int x),
1542 hook_void_rtx_insn_int)
1544 /* The following member value is a a function that returns true is
1545 dispatch schedling is supported in hardware and condition passed
1546 as the second parameter is true. */
1547 DEFHOOK
1548 (dispatch,
1549 "This hook is called by Haifa Scheduler. It returns true if dispatch scheduling\n\
1550 is supported in hardware and the condition specified in the parameter is true.",
1551 bool, (rtx_insn *insn, int x),
1552 hook_bool_rtx_insn_int_false)
1554 DEFHOOKPOD
1555 (exposed_pipeline,
1556 "True if the processor has an exposed pipeline, which means that not just\n\
1557 the order of instructions is important for correctness when scheduling, but\n\
1558 also the latencies of operations.",
1559 bool, false)
1561 /* The following member value is a function that returns number
1562 of operations reassociator should try to put in parallel for
1563 statements of the given type. By default 1 is used. */
1564 DEFHOOK
1565 (reassociation_width,
1566 "This hook is called by tree reassociator to determine a level of\n\
1567 parallelism required in output calculations chain.",
1568 int, (unsigned int opc, machine_mode mode),
1569 hook_int_uint_mode_1)
1571 /* The following member value is a function that returns priority for
1572 fusion of each instruction via pointer parameters. */
1573 DEFHOOK
1574 (fusion_priority,
1575 "This hook is called by scheduling fusion pass. It calculates fusion\n\
1576 priorities for each instruction passed in by parameter. The priorities\n\
1577 are returned via pointer parameters.\n\
1579 @var{insn} is the instruction whose priorities need to be calculated.\n\
1580 @var{max_pri} is the maximum priority can be returned in any cases.\n\
1581 @var{fusion_pri} is the pointer parameter through which @var{insn}'s\n\
1582 fusion priority should be calculated and returned.\n\
1583 @var{pri} is the pointer parameter through which @var{insn}'s priority\n\
1584 should be calculated and returned.\n\
1586 Same @var{fusion_pri} should be returned for instructions which should\n\
1587 be scheduled together. Different @var{pri} should be returned for\n\
1588 instructions with same @var{fusion_pri}. @var{fusion_pri} is the major\n\
1589 sort key, @var{pri} is the minor sort key. All instructions will be\n\
1590 scheduled according to the two priorities. All priorities calculated\n\
1591 should be between 0 (exclusive) and @var{max_pri} (inclusive). To avoid\n\
1592 false dependencies, @var{fusion_pri} of instructions which need to be\n\
1593 scheduled together should be smaller than @var{fusion_pri} of irrelevant\n\
1594 instructions.\n\
1596 Given below example:\n\
1598 @smallexample\n\
1599 ldr r10, [r1, 4]\n\
1600 add r4, r4, r10\n\
1601 ldr r15, [r2, 8]\n\
1602 sub r5, r5, r15\n\
1603 ldr r11, [r1, 0]\n\
1604 add r4, r4, r11\n\
1605 ldr r16, [r2, 12]\n\
1606 sub r5, r5, r16\n\
1607 @end smallexample\n\
1609 On targets like ARM/AArch64, the two pairs of consecutive loads should be\n\
1610 merged. Since peephole2 pass can't help in this case unless consecutive\n\
1611 loads are actually next to each other in instruction flow. That's where\n\
1612 this scheduling fusion pass works. This hook calculates priority for each\n\
1613 instruction based on its fustion type, like:\n\
1615 @smallexample\n\
1616 ldr r10, [r1, 4] ; fusion_pri=99, pri=96\n\
1617 add r4, r4, r10 ; fusion_pri=100, pri=100\n\
1618 ldr r15, [r2, 8] ; fusion_pri=98, pri=92\n\
1619 sub r5, r5, r15 ; fusion_pri=100, pri=100\n\
1620 ldr r11, [r1, 0] ; fusion_pri=99, pri=100\n\
1621 add r4, r4, r11 ; fusion_pri=100, pri=100\n\
1622 ldr r16, [r2, 12] ; fusion_pri=98, pri=88\n\
1623 sub r5, r5, r16 ; fusion_pri=100, pri=100\n\
1624 @end smallexample\n\
1626 Scheduling fusion pass then sorts all ready to issue instructions according\n\
1627 to the priorities. As a result, instructions of same fusion type will be\n\
1628 pushed together in instruction flow, like:\n\
1630 @smallexample\n\
1631 ldr r11, [r1, 0]\n\
1632 ldr r10, [r1, 4]\n\
1633 ldr r15, [r2, 8]\n\
1634 ldr r16, [r2, 12]\n\
1635 add r4, r4, r10\n\
1636 sub r5, r5, r15\n\
1637 add r4, r4, r11\n\
1638 sub r5, r5, r16\n\
1639 @end smallexample\n\
1641 Now peephole2 pass can simply merge the two pairs of loads.\n\
1643 Since scheduling fusion pass relies on peephole2 to do real fusion\n\
1644 work, it is only enabled by default when peephole2 is in effect.\n\
1646 This is firstly introduced on ARM/AArch64 targets, please refer to\n\
1647 the hook implementation for how different fusion types are supported.",
1648 void, (rtx_insn *insn, int max_pri, int *fusion_pri, int *pri), NULL)
1650 HOOK_VECTOR_END (sched)
1652 /* Functions relating to OpenMP SIMD and __attribute__((simd)) clones. */
1653 #undef HOOK_PREFIX
1654 #define HOOK_PREFIX "TARGET_SIMD_CLONE_"
1655 HOOK_VECTOR (TARGET_SIMD_CLONE, simd_clone)
1657 DEFHOOK
1658 (compute_vecsize_and_simdlen,
1659 "This hook should set @var{vecsize_mangle}, @var{vecsize_int}, @var{vecsize_float}\n\
1660 fields in @var{simd_clone} structure pointed by @var{clone_info} argument and also\n\
1661 @var{simdlen} field if it was previously 0.\n\
1662 The hook should return 0 if SIMD clones shouldn't be emitted,\n\
1663 or number of @var{vecsize_mangle} variants that should be emitted.",
1664 int, (struct cgraph_node *, struct cgraph_simd_clone *, tree, int), NULL)
1666 DEFHOOK
1667 (adjust,
1668 "This hook should add implicit @code{attribute(target(\"...\"))} attribute\n\
1669 to SIMD clone @var{node} if needed.",
1670 void, (struct cgraph_node *), NULL)
1672 DEFHOOK
1673 (usable,
1674 "This hook should return -1 if SIMD clone @var{node} shouldn't be used\n\
1675 in vectorized loops in current function, or non-negative number if it is\n\
1676 usable. In that case, the smaller the number is, the more desirable it is\n\
1677 to use it.",
1678 int, (struct cgraph_node *), NULL)
1680 HOOK_VECTOR_END (simd_clone)
1682 /* Functions relating to OpenMP SIMT vectorization transform. */
1683 #undef HOOK_PREFIX
1684 #define HOOK_PREFIX "TARGET_SIMT_"
1685 HOOK_VECTOR (TARGET_SIMT, simt)
1687 DEFHOOK
1688 (vf,
1689 "Return number of threads in SIMT thread group on the target.",
1690 int, (void), NULL)
1692 HOOK_VECTOR_END (simt)
1694 /* Functions relating to openacc. */
1695 #undef HOOK_PREFIX
1696 #define HOOK_PREFIX "TARGET_GOACC_"
1697 HOOK_VECTOR (TARGET_GOACC, goacc)
1699 DEFHOOK
1700 (validate_dims,
1701 "This hook should check the launch dimensions provided for an OpenACC\n\
1702 compute region, or routine. Defaulted values are represented as -1\n\
1703 and non-constant values as 0. The @var{fn_level} is negative for the\n\
1704 function corresponding to the compute region. For a routine is is the\n\
1705 outermost level at which partitioned execution may be spawned. The hook\n\
1706 should verify non-default values. If DECL is NULL, global defaults\n\
1707 are being validated and unspecified defaults should be filled in.\n\
1708 Diagnostics should be issued as appropriate. Return\n\
1709 true, if changes have been made. You must override this hook to\n\
1710 provide dimensions larger than 1.",
1711 bool, (tree decl, int *dims, int fn_level),
1712 default_goacc_validate_dims)
1714 DEFHOOK
1715 (dim_limit,
1716 "This hook should return the maximum size of a particular dimension,\n\
1717 or zero if unbounded.",
1718 int, (int axis),
1719 default_goacc_dim_limit)
1721 DEFHOOK
1722 (fork_join,
1723 "This hook can be used to convert IFN_GOACC_FORK and IFN_GOACC_JOIN\n\
1724 function calls to target-specific gimple, or indicate whether they\n\
1725 should be retained. It is executed during the oacc_device_lower pass.\n\
1726 It should return true, if the call should be retained. It should\n\
1727 return false, if it is to be deleted (either because target-specific\n\
1728 gimple has been inserted before it, or there is no need for it).\n\
1729 The default hook returns false, if there are no RTL expanders for them.",
1730 bool, (gcall *call, const int *dims, bool is_fork),
1731 default_goacc_fork_join)
1733 DEFHOOK
1734 (reduction,
1735 "This hook is used by the oacc_transform pass to expand calls to the\n\
1736 @var{GOACC_REDUCTION} internal function, into a sequence of gimple\n\
1737 instructions. @var{call} is gimple statement containing the call to\n\
1738 the function. This hook removes statement @var{call} after the\n\
1739 expanded sequence has been inserted. This hook is also responsible\n\
1740 for allocating any storage for reductions when necessary.",
1741 void, (gcall *call),
1742 default_goacc_reduction)
1744 HOOK_VECTOR_END (goacc)
1746 /* Functions relating to vectorization. */
1747 #undef HOOK_PREFIX
1748 #define HOOK_PREFIX "TARGET_VECTORIZE_"
1749 HOOK_VECTOR (TARGET_VECTORIZE, vectorize)
1751 /* The following member value is a pointer to a function called
1752 by the vectorizer, and return the decl of the target builtin
1753 function. */
1754 DEFHOOK
1755 (builtin_mask_for_load,
1756 "This hook should return the DECL of a function @var{f} that given an\n\
1757 address @var{addr} as an argument returns a mask @var{m} that can be\n\
1758 used to extract from two vectors the relevant data that resides in\n\
1759 @var{addr} in case @var{addr} is not properly aligned.\n\
1761 The autovectorizer, when vectorizing a load operation from an address\n\
1762 @var{addr} that may be unaligned, will generate two vector loads from\n\
1763 the two aligned addresses around @var{addr}. It then generates a\n\
1764 @code{REALIGN_LOAD} operation to extract the relevant data from the\n\
1765 two loaded vectors. The first two arguments to @code{REALIGN_LOAD},\n\
1766 @var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and\n\
1767 the third argument, @var{OFF}, defines how the data will be extracted\n\
1768 from these two vectors: if @var{OFF} is 0, then the returned vector is\n\
1769 @var{v2}; otherwise, the returned vector is composed from the last\n\
1770 @var{VS}-@var{OFF} elements of @var{v1} concatenated to the first\n\
1771 @var{OFF} elements of @var{v2}.\n\
1773 If this hook is defined, the autovectorizer will generate a call\n\
1774 to @var{f} (using the DECL tree that this hook returns) and will\n\
1775 use the return value of @var{f} as the argument @var{OFF} to\n\
1776 @code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}\n\
1777 should comply with the semantics expected by @code{REALIGN_LOAD}\n\
1778 described above.\n\
1779 If this hook is not defined, then @var{addr} will be used as\n\
1780 the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low\n\
1781 log2(@var{VS}) @minus{} 1 bits of @var{addr} will be considered.",
1782 tree, (void), NULL)
1784 /* Returns a built-in function that realizes the vectorized version of
1785 a target-independent function, or NULL_TREE if not available. */
1786 DEFHOOK
1787 (builtin_vectorized_function,
1788 "This hook should return the decl of a function that implements the\n\
1789 vectorized variant of the function with the @code{combined_fn} code\n\
1790 @var{code} or @code{NULL_TREE} if such a function is not available.\n\
1791 The return type of the vectorized function shall be of vector type\n\
1792 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1793 tree, (unsigned code, tree vec_type_out, tree vec_type_in),
1794 default_builtin_vectorized_function)
1796 /* Returns a built-in function that realizes the vectorized version of
1797 a target-specific function, or NULL_TREE if not available. */
1798 DEFHOOK
1799 (builtin_md_vectorized_function,
1800 "This hook should return the decl of a function that implements the\n\
1801 vectorized variant of target built-in function @code{fndecl}. The\n\
1802 return type of the vectorized function shall be of vector type\n\
1803 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1804 tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
1805 default_builtin_md_vectorized_function)
1807 /* Returns a function declaration for a builtin that realizes the
1808 vector conversion, or NULL_TREE if not available. */
1809 DEFHOOK
1810 (builtin_conversion,
1811 "This hook should return the DECL of a function that implements conversion of the\n\
1812 input vector of type @var{src_type} to type @var{dest_type}.\n\
1813 The value of @var{code} is one of the enumerators in @code{enum tree_code} and\n\
1814 specifies how the conversion is to be applied\n\
1815 (truncation, rounding, etc.).\n\
1817 If this hook is defined, the autovectorizer will use the\n\
1818 @code{TARGET_VECTORIZE_BUILTIN_CONVERSION} target hook when vectorizing\n\
1819 conversion. Otherwise, it will return @code{NULL_TREE}.",
1820 tree, (unsigned code, tree dest_type, tree src_type),
1821 default_builtin_vectorized_conversion)
1823 /* Cost of different vector/scalar statements in vectorization cost
1824 model. In case of misaligned vector loads and stores the cost depends
1825 on the data type and misalignment value. */
1826 DEFHOOK
1827 (builtin_vectorization_cost,
1828 "Returns cost of different scalar or vector statements for vectorization cost model.\n\
1829 For vector memory operations the cost may depend on type (@var{vectype}) and\n\
1830 misalignment value (@var{misalign}).",
1831 int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
1832 default_builtin_vectorization_cost)
1834 DEFHOOK
1835 (preferred_vector_alignment,
1836 "This hook returns the preferred alignment in bits for accesses to\n\
1837 vectors of type @var{type} in vectorized code. This might be less than\n\
1838 or greater than the ABI-defined value returned by\n\
1839 @code{TARGET_VECTOR_ALIGNMENT}. It can be equal to the alignment of\n\
1840 a single element, in which case the vectorizer will not try to optimize\n\
1841 for alignment.\n\
1843 The default hook returns @code{TYPE_ALIGN (@var{type})}, which is\n\
1844 correct for most targets.",
1845 HOST_WIDE_INT, (const_tree type),
1846 default_preferred_vector_alignment)
1848 /* Return true if vector alignment is reachable (by peeling N
1849 iterations) for the given scalar type. */
1850 DEFHOOK
1851 (vector_alignment_reachable,
1852 "Return true if vector alignment is reachable (by peeling N iterations) for the given scalar type @var{type}. @var{is_packed} is false if the scalar access using @var{type} is known to be naturally aligned.",
1853 bool, (const_tree type, bool is_packed),
1854 default_builtin_vector_alignment_reachable)
1856 DEFHOOK
1857 (vec_perm_const,
1858 "This hook is used to test whether the target can permute up to two\n\
1859 vectors of mode @var{mode} using the permutation vector @code{sel}, and\n\
1860 also to emit such a permutation. In the former case @var{in0}, @var{in1}\n\
1861 and @var{out} are all null. In the latter case @var{in0} and @var{in1} are\n\
1862 the source vectors and @var{out} is the destination vector; all three are\n\
1863 registers of mode @var{mode}. @var{in1} is the same as @var{in0} if\n\
1864 @var{sel} describes a permutation on one vector instead of two.\n\
1866 Return true if the operation is possible, emitting instructions for it\n\
1867 if rtxes are provided.\n\
1869 @cindex @code{vec_perm@var{m}} instruction pattern\n\
1870 If the hook returns false for a mode with multibyte elements, GCC will\n\
1871 try the equivalent byte operation. If that also fails, it will try forcing\n\
1872 the selector into a register and using the @var{vec_perm@var{mode}}\n\
1873 instruction pattern. There is no need for the hook to handle these two\n\
1874 implementation approaches itself.",
1875 bool, (machine_mode mode, rtx output, rtx in0, rtx in1,
1876 const vec_perm_indices &sel),
1877 NULL)
1879 /* Return true if the target supports misaligned store/load of a
1880 specific factor denoted in the third parameter. The last parameter
1881 is true if the access is defined in a packed struct. */
1882 DEFHOOK
1883 (support_vector_misalignment,
1884 "This hook should return true if the target supports misaligned vector\n\
1885 store/load of a specific factor denoted in the @var{misalignment}\n\
1886 parameter. The vector store/load should be of machine mode @var{mode} and\n\
1887 the elements in the vectors should be of type @var{type}. @var{is_packed}\n\
1888 parameter is true if the memory access is defined in a packed struct.",
1889 bool,
1890 (machine_mode mode, const_tree type, int misalignment, bool is_packed),
1891 default_builtin_support_vector_misalignment)
1893 /* Returns the preferred mode for SIMD operations for the specified
1894 scalar mode. */
1895 DEFHOOK
1896 (preferred_simd_mode,
1897 "This hook should return the preferred mode for vectorizing scalar\n\
1898 mode @var{mode}. The default is\n\
1899 equal to @code{word_mode}, because the vectorizer can do some\n\
1900 transformations even in absence of specialized @acronym{SIMD} hardware.",
1901 machine_mode,
1902 (scalar_mode mode),
1903 default_preferred_simd_mode)
1905 /* Returns the preferred mode for splitting SIMD reductions to. */
1906 DEFHOOK
1907 (split_reduction,
1908 "This hook should return the preferred mode to split the final reduction\n\
1909 step on @var{mode} to. The reduction is then carried out reducing upper\n\
1910 against lower halves of vectors recursively until the specified mode is\n\
1911 reached. The default is @var{mode} which means no splitting.",
1912 machine_mode,
1913 (machine_mode),
1914 default_split_reduction)
1916 /* Returns a mask of vector sizes to iterate over when auto-vectorizing
1917 after processing the preferred one derived from preferred_simd_mode. */
1918 DEFHOOK
1919 (autovectorize_vector_sizes,
1920 "If the mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE} is not\n\
1921 the only one that is worth considering, this hook should add all suitable\n\
1922 vector sizes to @var{sizes}, in order of decreasing preference. The first\n\
1923 one should be the size of @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}.\n\
1925 The hook does not need to do anything if the vector returned by\n\
1926 @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE} is the only one relevant\n\
1927 for autovectorization. The default implementation does nothing.",
1928 void,
1929 (vector_sizes *sizes),
1930 default_autovectorize_vector_sizes)
1932 /* Function to get a target mode for a vector mask. */
1933 DEFHOOK
1934 (get_mask_mode,
1935 "A vector mask is a value that holds one boolean result for every element\n\
1936 in a vector. This hook returns the machine mode that should be used to\n\
1937 represent such a mask when the vector in question is @var{length} bytes\n\
1938 long and contains @var{nunits} elements. The hook returns an empty\n\
1939 @code{opt_machine_mode} if no such mode exists.\n\
1941 The default implementation returns the mode of an integer vector that\n\
1942 is @var{length} bytes long and that contains @var{nunits} elements,\n\
1943 if such a mode exists.",
1944 opt_machine_mode,
1945 (poly_uint64 nunits, poly_uint64 length),
1946 default_get_mask_mode)
1948 /* Function to say whether a masked operation is expensive when the
1949 mask is all zeros. */
1950 DEFHOOK
1951 (empty_mask_is_expensive,
1952 "This hook returns true if masked internal function @var{ifn} (really of\n\
1953 type @code{internal_fn}) should be considered expensive when the mask is\n\
1954 all zeros. GCC can then try to branch around the instruction instead.",
1955 bool,
1956 (unsigned ifn),
1957 default_empty_mask_is_expensive)
1959 /* Target builtin that implements vector gather operation. */
1960 DEFHOOK
1961 (builtin_gather,
1962 "Target builtin that implements vector gather operation. @var{mem_vectype}\n\
1963 is the vector type of the load and @var{index_type} is scalar type of\n\
1964 the index, scaled by @var{scale}.\n\
1965 The default is @code{NULL_TREE} which means to not vectorize gather\n\
1966 loads.",
1967 tree,
1968 (const_tree mem_vectype, const_tree index_type, int scale),
1969 NULL)
1971 /* Target builtin that implements vector scatter operation. */
1972 DEFHOOK
1973 (builtin_scatter,
1974 "Target builtin that implements vector scatter operation. @var{vectype}\n\
1975 is the vector type of the store and @var{index_type} is scalar type of\n\
1976 the index, scaled by @var{scale}.\n\
1977 The default is @code{NULL_TREE} which means to not vectorize scatter\n\
1978 stores.",
1979 tree,
1980 (const_tree vectype, const_tree index_type, int scale),
1981 NULL)
1983 /* Target function to initialize the cost model for a loop or block. */
1984 DEFHOOK
1985 (init_cost,
1986 "This hook should initialize target-specific data structures in preparation "
1987 "for modeling the costs of vectorizing a loop or basic block. The default "
1988 "allocates three unsigned integers for accumulating costs for the prologue, "
1989 "body, and epilogue of the loop or basic block. If @var{loop_info} is "
1990 "non-NULL, it identifies the loop being vectorized; otherwise a single block "
1991 "is being vectorized.",
1992 void *,
1993 (struct loop *loop_info),
1994 default_init_cost)
1996 /* Target function to record N statements of the given kind using the
1997 given vector type within the cost model data for the current loop or
1998 block. */
1999 DEFHOOK
2000 (add_stmt_cost,
2001 "This hook should update the target-specific @var{data} in response to "
2002 "adding @var{count} copies of the given @var{kind} of statement to a "
2003 "loop or basic block. The default adds the builtin vectorizer cost for "
2004 "the copies of the statement to the accumulator specified by @var{where}, "
2005 "(the prologue, body, or epilogue) and returns the amount added. The "
2006 "return value should be viewed as a tentative cost that may later be "
2007 "revised.",
2008 unsigned,
2009 (void *data, int count, enum vect_cost_for_stmt kind,
2010 struct _stmt_vec_info *stmt_info, int misalign,
2011 enum vect_cost_model_location where),
2012 default_add_stmt_cost)
2014 /* Target function to calculate the total cost of the current vectorized
2015 loop or block. */
2016 DEFHOOK
2017 (finish_cost,
2018 "This hook should complete calculations of the cost of vectorizing a loop "
2019 "or basic block based on @var{data}, and return the prologue, body, and "
2020 "epilogue costs as unsigned integers. The default returns the value of "
2021 "the three accumulators.",
2022 void,
2023 (void *data, unsigned *prologue_cost, unsigned *body_cost,
2024 unsigned *epilogue_cost),
2025 default_finish_cost)
2027 /* Function to delete target-specific cost modeling data. */
2028 DEFHOOK
2029 (destroy_cost_data,
2030 "This hook should release @var{data} and any related data structures "
2031 "allocated by TARGET_VECTORIZE_INIT_COST. The default releases the "
2032 "accumulator.",
2033 void,
2034 (void *data),
2035 default_destroy_cost_data)
2037 HOOK_VECTOR_END (vectorize)
2039 #undef HOOK_PREFIX
2040 #define HOOK_PREFIX "TARGET_"
2042 DEFHOOK
2043 (record_offload_symbol,
2044 "Used when offloaded functions are seen in the compilation unit and no named\n\
2045 sections are available. It is called once for each symbol that must be\n\
2046 recorded in the offload function and variable table.",
2047 void, (tree),
2048 hook_void_tree)
2050 DEFHOOKPOD
2051 (absolute_biggest_alignment,
2052 "If defined, this target hook specifies the absolute biggest alignment\n\
2053 that a type or variable can have on this machine, otherwise,\n\
2054 @code{BIGGEST_ALIGNMENT} is used.",
2055 HOST_WIDE_INT, BIGGEST_ALIGNMENT)
2057 /* Allow target specific overriding of option settings after options have
2058 been changed by an attribute or pragma or when it is reset at the
2059 end of the code affected by an attribute or pragma. */
2060 DEFHOOK
2061 (override_options_after_change,
2062 "This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}\n\
2063 but is called when the optimize level is changed via an attribute or\n\
2064 pragma or when it is reset at the end of the code affected by the\n\
2065 attribute or pragma. It is not called at the beginning of compilation\n\
2066 when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these\n\
2067 actions then, you should have @code{TARGET_OPTION_OVERRIDE} call\n\
2068 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.",
2069 void, (void),
2070 hook_void_void)
2072 DEFHOOK
2073 (offload_options,
2074 "Used when writing out the list of options into an LTO file. It should\n\
2075 translate any relevant target-specific options (such as the ABI in use)\n\
2076 into one of the @option{-foffload} options that exist as a common interface\n\
2077 to express such options. It should return a string containing these options,\n\
2078 separated by spaces, which the caller will free.\n",
2079 char *, (void), hook_charptr_void_null)
2081 DEFHOOK_UNDOC
2082 (eh_return_filter_mode,
2083 "Return machine mode for filter value.",
2084 scalar_int_mode, (void),
2085 default_eh_return_filter_mode)
2087 /* Return machine mode for libgcc expanded cmp instructions. */
2088 DEFHOOK
2089 (libgcc_cmp_return_mode,
2090 "This target hook should return the mode to be used for the return value\n\
2091 of compare instructions expanded to libgcc calls. If not defined\n\
2092 @code{word_mode} is returned which is the right choice for a majority of\n\
2093 targets.",
2094 scalar_int_mode, (void),
2095 default_libgcc_cmp_return_mode)
2097 /* Return machine mode for libgcc expanded shift instructions. */
2098 DEFHOOK
2099 (libgcc_shift_count_mode,
2100 "This target hook should return the mode to be used for the shift count operand\n\
2101 of shift instructions expanded to libgcc calls. If not defined\n\
2102 @code{word_mode} is returned which is the right choice for a majority of\n\
2103 targets.",
2104 scalar_int_mode, (void),
2105 default_libgcc_shift_count_mode)
2107 /* Return machine mode to be used for _Unwind_Word type. */
2108 DEFHOOK
2109 (unwind_word_mode,
2110 "Return machine mode to be used for @code{_Unwind_Word} type.\n\
2111 The default is to use @code{word_mode}.",
2112 scalar_int_mode, (void),
2113 default_unwind_word_mode)
2115 /* Given two decls, merge their attributes and return the result. */
2116 DEFHOOK
2117 (merge_decl_attributes,
2118 "Define this target hook if the merging of decl attributes needs special\n\
2119 handling. If defined, the result is a list of the combined\n\
2120 @code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.\n\
2121 @var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of\n\
2122 when this is needed are when one attribute overrides another, or when an\n\
2123 attribute is nullified by a subsequent definition. This function may\n\
2124 call @code{merge_attributes} to handle machine-independent merging.\n\
2126 @findex TARGET_DLLIMPORT_DECL_ATTRIBUTES\n\
2127 If the only target-specific handling you require is @samp{dllimport}\n\
2128 for Microsoft Windows targets, you should define the macro\n\
2129 @code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler\n\
2130 will then define a function called\n\
2131 @code{merge_dllimport_decl_attributes} which can then be defined as\n\
2132 the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also\n\
2133 add @code{handle_dll_attribute} in the attribute table for your port\n\
2134 to perform initial processing of the @samp{dllimport} and\n\
2135 @samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and\n\
2136 @file{i386/i386.c}, for example.",
2137 tree, (tree olddecl, tree newdecl),
2138 merge_decl_attributes)
2140 /* Given two types, merge their attributes and return the result. */
2141 DEFHOOK
2142 (merge_type_attributes,
2143 "Define this target hook if the merging of type attributes needs special\n\
2144 handling. If defined, the result is a list of the combined\n\
2145 @code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed\n\
2146 that @code{comptypes} has already been called and returned 1. This\n\
2147 function may call @code{merge_attributes} to handle machine-independent\n\
2148 merging.",
2149 tree, (tree type1, tree type2),
2150 merge_type_attributes)
2152 /* Table of machine attributes and functions to handle them.
2153 Ignored if NULL. */
2154 DEFHOOKPOD
2155 (attribute_table,
2156 "If defined, this target hook points to an array of @samp{struct\n\
2157 attribute_spec} (defined in @file{tree-core.h}) specifying the machine\n\
2158 specific attributes for this target and some of the restrictions on the\n\
2159 entities to which these attributes are applied and the arguments they\n\
2160 take.",
2161 const struct attribute_spec *, NULL)
2163 /* Return true iff attribute NAME expects a plain identifier as its first
2164 argument. */
2165 DEFHOOK
2166 (attribute_takes_identifier_p,
2167 "If defined, this target hook is a function which returns true if the\n\
2168 machine-specific attribute named @var{name} expects an identifier\n\
2169 given as its first argument to be passed on as a plain identifier, not\n\
2170 subjected to name lookup. If this is not defined, the default is\n\
2171 false for all machine-specific attributes.",
2172 bool, (const_tree name),
2173 hook_bool_const_tree_false)
2175 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
2176 one if they are compatible and two if they are nearly compatible
2177 (which causes a warning to be generated). */
2178 DEFHOOK
2179 (comp_type_attributes,
2180 "If defined, this target hook is a function which returns zero if the attributes on\n\
2181 @var{type1} and @var{type2} are incompatible, one if they are compatible,\n\
2182 and two if they are nearly compatible (which causes a warning to be\n\
2183 generated). If this is not defined, machine-specific attributes are\n\
2184 supposed always to be compatible.",
2185 int, (const_tree type1, const_tree type2),
2186 hook_int_const_tree_const_tree_1)
2188 /* Assign default attributes to the newly defined TYPE. */
2189 DEFHOOK
2190 (set_default_type_attributes,
2191 "If defined, this target hook is a function which assigns default attributes to\n\
2192 the newly defined @var{type}.",
2193 void, (tree type),
2194 hook_void_tree)
2196 /* Insert attributes on the newly created DECL. */
2197 DEFHOOK
2198 (insert_attributes,
2199 "Define this target hook if you want to be able to add attributes to a decl\n\
2200 when it is being created. This is normally useful for back ends which\n\
2201 wish to implement a pragma by using the attributes which correspond to\n\
2202 the pragma's effect. The @var{node} argument is the decl which is being\n\
2203 created. The @var{attr_ptr} argument is a pointer to the attribute list\n\
2204 for this decl. The list itself should not be modified, since it may be\n\
2205 shared with other decls, but attributes may be chained on the head of\n\
2206 the list and @code{*@var{attr_ptr}} modified to point to the new\n\
2207 attributes, or a copy of the list may be made if further changes are\n\
2208 needed.",
2209 void, (tree node, tree *attr_ptr),
2210 hook_void_tree_treeptr)
2212 /* Return true if FNDECL (which has at least one machine attribute)
2213 can be inlined despite its machine attributes, false otherwise. */
2214 DEFHOOK
2215 (function_attribute_inlinable_p,
2216 "@cindex inlining\n\
2217 This target hook returns @code{true} if it is OK to inline @var{fndecl}\n\
2218 into the current function, despite its having target-specific\n\
2219 attributes, @code{false} otherwise. By default, if a function has a\n\
2220 target specific attribute attached to it, it will not be inlined.",
2221 bool, (const_tree fndecl),
2222 hook_bool_const_tree_false)
2224 /* Return true if bitfields in RECORD_TYPE should follow the
2225 Microsoft Visual C++ bitfield layout rules. */
2226 DEFHOOK
2227 (ms_bitfield_layout_p,
2228 "This target hook returns @code{true} if bit-fields in the given\n\
2229 @var{record_type} are to be laid out following the rules of Microsoft\n\
2230 Visual C/C++, namely: (i) a bit-field won't share the same storage\n\
2231 unit with the previous bit-field if their underlying types have\n\
2232 different sizes, and the bit-field will be aligned to the highest\n\
2233 alignment of the underlying types of itself and of the previous\n\
2234 bit-field; (ii) a zero-sized bit-field will affect the alignment of\n\
2235 the whole enclosing structure, even if it is unnamed; except that\n\
2236 (iii) a zero-sized bit-field will be disregarded unless it follows\n\
2237 another bit-field of nonzero size. If this hook returns @code{true},\n\
2238 other macros that control bit-field layout are ignored.\n\
2240 When a bit-field is inserted into a packed record, the whole size\n\
2241 of the underlying type is used by one or more same-size adjacent\n\
2242 bit-fields (that is, if its long:3, 32 bits is used in the record,\n\
2243 and any additional adjacent long bit-fields are packed into the same\n\
2244 chunk of 32 bits. However, if the size changes, a new field of that\n\
2245 size is allocated). In an unpacked record, this is the same as using\n\
2246 alignment, but not equivalent when packing.\n\
2248 If both MS bit-fields and @samp{__attribute__((packed))} are used,\n\
2249 the latter will take precedence. If @samp{__attribute__((packed))} is\n\
2250 used on a single field when MS bit-fields are in use, it will take\n\
2251 precedence for that field, but the alignment of the rest of the structure\n\
2252 may affect its placement.",
2253 bool, (const_tree record_type),
2254 hook_bool_const_tree_false)
2256 /* For now this is only an interface to WORDS_BIG_ENDIAN for
2257 target-independent code like the front ends, need performance testing
2258 before switching completely to the target hook. */
2259 DEFHOOK_UNDOC
2260 (words_big_endian,
2262 bool, (void),
2263 targhook_words_big_endian)
2265 /* Likewise for FLOAT_WORDS_BIG_ENDIAN. */
2266 DEFHOOK_UNDOC
2267 (float_words_big_endian,
2269 bool, (void),
2270 targhook_float_words_big_endian)
2272 DEFHOOK
2273 (float_exceptions_rounding_supported_p,
2274 "Returns true if the target supports IEEE 754 floating-point exceptions\
2275 and rounding modes, false otherwise. This is intended to relate to the\
2276 @code{float} and @code{double} types, but not necessarily @code{long double}.\
2277 By default, returns true if the @code{adddf3} instruction pattern is\
2278 available and false otherwise, on the assumption that hardware floating\
2279 point supports exceptions and rounding modes but software floating point\
2280 does not.",
2281 bool, (void),
2282 default_float_exceptions_rounding_supported_p)
2284 /* True if the target supports decimal floating point. */
2285 DEFHOOK
2286 (decimal_float_supported_p,
2287 "Returns true if the target supports decimal floating point.",
2288 bool, (void),
2289 default_decimal_float_supported_p)
2291 /* True if the target supports fixed-point. */
2292 DEFHOOK
2293 (fixed_point_supported_p,
2294 "Returns true if the target supports fixed-point arithmetic.",
2295 bool, (void),
2296 default_fixed_point_supported_p)
2298 /* Return true if anonymous bitfields affect structure alignment. */
2299 DEFHOOK
2300 (align_anon_bitfield,
2301 "When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine\n\
2302 whether unnamed bitfields affect the alignment of the containing\n\
2303 structure. The hook should return true if the structure should inherit\n\
2304 the alignment requirements of an unnamed bitfield's type.",
2305 bool, (void),
2306 hook_bool_void_false)
2308 /* Return true if volatile bitfields should use the narrowest type possible.
2309 Return false if they should use the container type. */
2310 DEFHOOK
2311 (narrow_volatile_bitfield,
2312 "This target hook should return @code{true} if accesses to volatile bitfields\n\
2313 should use the narrowest mode possible. It should return @code{false} if\n\
2314 these accesses should use the bitfield container type.\n\
2316 The default is @code{false}.",
2317 bool, (void),
2318 hook_bool_void_false)
2320 /* Set up target-specific built-in functions. */
2321 DEFHOOK
2322 (init_builtins,
2323 "Define this hook if you have any machine-specific built-in functions\n\
2324 that need to be defined. It should be a function that performs the\n\
2325 necessary setup.\n\
2327 Machine specific built-in functions can be useful to expand special machine\n\
2328 instructions that would otherwise not normally be generated because\n\
2329 they have no equivalent in the source language (for example, SIMD vector\n\
2330 instructions or prefetch instructions).\n\
2332 To create a built-in function, call the function\n\
2333 @code{lang_hooks.builtin_function}\n\
2334 which is defined by the language front end. You can use any type nodes set\n\
2335 up by @code{build_common_tree_nodes};\n\
2336 only language front ends that use those two functions will call\n\
2337 @samp{TARGET_INIT_BUILTINS}.",
2338 void, (void),
2339 hook_void_void)
2341 /* Initialize (if INITIALIZE_P is true) and return the target-specific
2342 built-in function decl for CODE.
2343 Return NULL if that is not possible. Return error_mark_node if CODE
2344 is outside of the range of valid target builtin function codes. */
2345 DEFHOOK
2346 (builtin_decl,
2347 "Define this hook if you have any machine-specific built-in functions\n\
2348 that need to be defined. It should be a function that returns the\n\
2349 builtin function declaration for the builtin function code @var{code}.\n\
2350 If there is no such builtin and it cannot be initialized at this time\n\
2351 if @var{initialize_p} is true the function should return @code{NULL_TREE}.\n\
2352 If @var{code} is out of range the function should return\n\
2353 @code{error_mark_node}.",
2354 tree, (unsigned code, bool initialize_p), NULL)
2356 /* Expand a target-specific builtin. */
2357 DEFHOOK
2358 (expand_builtin,
2359 "\n\
2360 Expand a call to a machine specific built-in function that was set up by\n\
2361 @samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the\n\
2362 function call; the result should go to @var{target} if that is\n\
2363 convenient, and have mode @var{mode} if that is convenient.\n\
2364 @var{subtarget} may be used as the target for computing one of\n\
2365 @var{exp}'s operands. @var{ignore} is nonzero if the value is to be\n\
2366 ignored. This function should return the result of the call to the\n\
2367 built-in function.",
2368 rtx,
2369 (tree exp, rtx target, rtx subtarget, machine_mode mode, int ignore),
2370 default_expand_builtin)
2372 /* Select a replacement for a target-specific builtin. This is done
2373 *before* regular type checking, and so allows the target to
2374 implement a crude form of function overloading. The result is a
2375 complete expression that implements the operation. PARAMS really
2376 has type VEC(tree,gc)*, but we don't want to include tree.h here. */
2377 DEFHOOK
2378 (resolve_overloaded_builtin,
2379 "Select a replacement for a machine specific built-in function that\n\
2380 was set up by @samp{TARGET_INIT_BUILTINS}. This is done\n\
2381 @emph{before} regular type checking, and so allows the target to\n\
2382 implement a crude form of function overloading. @var{fndecl} is the\n\
2383 declaration of the built-in function. @var{arglist} is the list of\n\
2384 arguments passed to the built-in function. The result is a\n\
2385 complete expression that implements the operation, usually\n\
2386 another @code{CALL_EXPR}.\n\
2387 @var{arglist} really has type @samp{VEC(tree,gc)*}",
2388 tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
2390 /* Fold a target-specific builtin to a tree valid for both GIMPLE
2391 and GENERIC. */
2392 DEFHOOK
2393 (fold_builtin,
2394 "Fold a call to a machine specific built-in function that was set up by\n\
2395 @samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the\n\
2396 built-in function. @var{n_args} is the number of arguments passed to\n\
2397 the function; the arguments themselves are pointed to by @var{argp}.\n\
2398 The result is another tree, valid for both GIMPLE and GENERIC,\n\
2399 containing a simplified expression for the call's result. If\n\
2400 @var{ignore} is true the value will be ignored.",
2401 tree, (tree fndecl, int n_args, tree *argp, bool ignore),
2402 hook_tree_tree_int_treep_bool_null)
2404 /* Fold a target-specific builtin to a valid GIMPLE tree. */
2405 DEFHOOK
2406 (gimple_fold_builtin,
2407 "Fold a call to a machine specific built-in function that was set up\n\
2408 by @samp{TARGET_INIT_BUILTINS}. @var{gsi} points to the gimple\n\
2409 statement holding the function call. Returns true if any change\n\
2410 was made to the GIMPLE stream.",
2411 bool, (gimple_stmt_iterator *gsi),
2412 hook_bool_gsiptr_false)
2414 /* Target hook is used to compare the target attributes in two functions to
2415 determine which function's features get higher priority. This is used
2416 during function multi-versioning to figure out the order in which two
2417 versions must be dispatched. A function version with a higher priority
2418 is checked for dispatching earlier. DECL1 and DECL2 are
2419 the two function decls that will be compared. It returns positive value
2420 if DECL1 is higher priority, negative value if DECL2 is higher priority
2421 and 0 if they are the same. */
2422 DEFHOOK
2423 (compare_version_priority,
2424 "This hook is used to compare the target attributes in two functions to\n\
2425 determine which function's features get higher priority. This is used\n\
2426 during function multi-versioning to figure out the order in which two\n\
2427 versions must be dispatched. A function version with a higher priority\n\
2428 is checked for dispatching earlier. @var{decl1} and @var{decl2} are\n\
2429 the two function decls that will be compared.",
2430 int, (tree decl1, tree decl2), NULL)
2432 /* Target hook is used to generate the dispatcher logic to invoke the right
2433 function version at run-time for a given set of function versions.
2434 ARG points to the callgraph node of the dispatcher function whose body
2435 must be generated. */
2436 DEFHOOK
2437 (generate_version_dispatcher_body,
2438 "This hook is used to generate the dispatcher logic to invoke the right\n\
2439 function version at run-time for a given set of function versions.\n\
2440 @var{arg} points to the callgraph node of the dispatcher function whose\n\
2441 body must be generated.",
2442 tree, (void *arg), NULL)
2444 /* Target hook is used to get the dispatcher function for a set of function
2445 versions. The dispatcher function is called to invoke the right function
2446 version at run-time. DECL is one version from a set of semantically
2447 identical versions. */
2448 DEFHOOK
2449 (get_function_versions_dispatcher,
2450 "This hook is used to get the dispatcher function for a set of function\n\
2451 versions. The dispatcher function is called to invoke the right function\n\
2452 version at run-time. @var{decl} is one version from a set of semantically\n\
2453 identical versions.",
2454 tree, (void *decl), NULL)
2456 /* Returns a code for a target-specific builtin that implements
2457 reciprocal of a target-specific function, or NULL_TREE if not available. */
2458 DEFHOOK
2459 (builtin_reciprocal,
2460 "This hook should return the DECL of a function that implements the\n\
2461 reciprocal of the machine-specific builtin function @var{fndecl}, or\n\
2462 @code{NULL_TREE} if such a function is not available.",
2463 tree, (tree fndecl),
2464 default_builtin_reciprocal)
2466 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
2467 string containing the C++ mangling for TYPE. In all other cases, return
2468 NULL. */
2469 DEFHOOK
2470 (mangle_type,
2471 "If your target defines any fundamental types, or any types your target\n\
2472 uses should be mangled differently from the default, define this hook\n\
2473 to return the appropriate encoding for these types as part of a C++\n\
2474 mangled name. The @var{type} argument is the tree structure representing\n\
2475 the type to be mangled. The hook may be applied to trees which are\n\
2476 not target-specific fundamental types; it should return @code{NULL}\n\
2477 for all such types, as well as arguments it does not recognize. If the\n\
2478 return value is not @code{NULL}, it must point to a statically-allocated\n\
2479 string constant.\n\
2481 Target-specific fundamental types might be new fundamental types or\n\
2482 qualified versions of ordinary fundamental types. Encode new\n\
2483 fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}\n\
2484 is the name used for the type in source code, and @var{n} is the\n\
2485 length of @var{name} in decimal. Encode qualified versions of\n\
2486 ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where\n\
2487 @var{name} is the name used for the type qualifier in source code,\n\
2488 @var{n} is the length of @var{name} as above, and @var{code} is the\n\
2489 code used to represent the unqualified version of this type. (See\n\
2490 @code{write_builtin_type} in @file{cp/mangle.c} for the list of\n\
2491 codes.) In both cases the spaces are for clarity; do not include any\n\
2492 spaces in your string.\n\
2494 This hook is applied to types prior to typedef resolution. If the mangled\n\
2495 name for a particular type depends only on that type's main variant, you\n\
2496 can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}\n\
2497 before mangling.\n\
2499 The default version of this hook always returns @code{NULL}, which is\n\
2500 appropriate for a target that does not define any new fundamental\n\
2501 types.",
2502 const char *, (const_tree type),
2503 hook_constcharptr_const_tree_null)
2505 /* Make any adjustments to libfunc names needed for this target. */
2506 DEFHOOK
2507 (init_libfuncs,
2508 "This hook should declare additional library routines or rename\n\
2509 existing ones, using the functions @code{set_optab_libfunc} and\n\
2510 @code{init_one_libfunc} defined in @file{optabs.c}.\n\
2511 @code{init_optabs} calls this macro after initializing all the normal\n\
2512 library routines.\n\
2514 The default is to do nothing. Most ports don't need to define this hook.",
2515 void, (void),
2516 hook_void_void)
2518 /* Add a __gnu_ prefix to library functions rather than just __. */
2519 DEFHOOKPOD
2520 (libfunc_gnu_prefix,
2521 "If false (the default), internal library routines start with two\n\
2522 underscores. If set to true, these routines start with @code{__gnu_}\n\
2523 instead. E.g., @code{__muldi3} changes to @code{__gnu_muldi3}. This\n\
2524 currently only affects functions defined in @file{libgcc2.c}. If this\n\
2525 is set to true, the @file{tm.h} file must also\n\
2526 @code{#define LIBGCC2_GNU_PREFIX}.",
2527 bool, false)
2529 /* Given a decl, a section name, and whether the decl initializer
2530 has relocs, choose attributes for the section. */
2531 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
2532 DEFHOOK
2533 (section_type_flags,
2534 "Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}\n\
2535 based on a variable or function decl, a section name, and whether or not the\n\
2536 declaration's initializer may contain runtime relocations. @var{decl} may be\n\
2537 null, in which case read-write data should be assumed.\n\
2539 The default version of this function handles choosing code vs data,\n\
2540 read-only vs read-write data, and @code{flag_pic}. You should only\n\
2541 need to override this if your target has special flags that might be\n\
2542 set via @code{__attribute__}.",
2543 unsigned int, (tree decl, const char *name, int reloc),
2544 default_section_type_flags)
2546 DEFHOOK
2547 (libc_has_function,
2548 "This hook determines whether a function from a class of functions\n\
2549 @var{fn_class} is present at the runtime.",
2550 bool, (enum function_class fn_class),
2551 default_libc_has_function)
2553 /* True if new jumps cannot be created, to replace existing ones or
2554 not, at the current point in the compilation. */
2555 DEFHOOK
2556 (cannot_modify_jumps_p,
2557 "This target hook returns @code{true} past the point in which new jump\n\
2558 instructions could be created. On machines that require a register for\n\
2559 every jump such as the SHmedia ISA of SH5, this point would typically be\n\
2560 reload, so this target hook should be defined to a function such as:\n\
2562 @smallexample\n\
2563 static bool\n\
2564 cannot_modify_jumps_past_reload_p ()\n\
2565 @{\n\
2566 return (reload_completed || reload_in_progress);\n\
2567 @}\n\
2568 @end smallexample",
2569 bool, (void),
2570 hook_bool_void_false)
2572 /* True if FOLLOWER may be modified to follow FOLLOWEE. */
2573 DEFHOOK
2574 (can_follow_jump,
2575 "FOLLOWER and FOLLOWEE are JUMP_INSN instructions;\
2576 return true if FOLLOWER may be modified to follow FOLLOWEE;\
2577 false, if it can't.\
2578 For example, on some targets, certain kinds of branches can't be made to\
2579 follow through a hot/cold partitioning.",
2580 bool, (const rtx_insn *follower, const rtx_insn *followee),
2581 hook_bool_const_rtx_insn_const_rtx_insn_true)
2583 /* Return a register class for which branch target register
2584 optimizations should be applied. */
2585 DEFHOOK
2586 (branch_target_register_class,
2587 "This target hook returns a register class for which branch target register\n\
2588 optimizations should be applied. All registers in this class should be\n\
2589 usable interchangeably. After reload, registers in this class will be\n\
2590 re-allocated and loads will be hoisted out of loops and be subjected\n\
2591 to inter-block scheduling.",
2592 reg_class_t, (void),
2593 default_branch_target_register_class)
2595 /* Return true if branch target register optimizations should include
2596 callee-saved registers that are not already live during the current
2597 function. AFTER_PE_GEN is true if prologues and epilogues have
2598 already been generated. */
2599 DEFHOOK
2600 (branch_target_register_callee_saved,
2601 "Branch target register optimization will by default exclude callee-saved\n\
2602 registers\n\
2603 that are not already live during the current function; if this target hook\n\
2604 returns true, they will be included. The target code must than make sure\n\
2605 that all target registers in the class returned by\n\
2606 @samp{TARGET_BRANCH_TARGET_REGISTER_CLASS} that might need saving are\n\
2607 saved. @var{after_prologue_epilogue_gen} indicates if prologues and\n\
2608 epilogues have already been generated. Note, even if you only return\n\
2609 true when @var{after_prologue_epilogue_gen} is false, you still are likely\n\
2610 to have to make special provisions in @code{INITIAL_ELIMINATION_OFFSET}\n\
2611 to reserve space for caller-saved target registers.",
2612 bool, (bool after_prologue_epilogue_gen),
2613 hook_bool_bool_false)
2615 /* Return true if the target supports conditional execution. */
2616 DEFHOOK
2617 (have_conditional_execution,
2618 "This target hook returns true if the target supports conditional execution.\n\
2619 This target hook is required only when the target has several different\n\
2620 modes and they have different conditional execution capability, such as ARM.",
2621 bool, (void),
2622 default_have_conditional_execution)
2624 DEFHOOK
2625 (gen_ccmp_first,
2626 "This function prepares to emit a comparison insn for the first compare in a\n\
2627 sequence of conditional comparisions. It returns an appropriate comparison\n\
2628 with @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2629 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2630 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2631 compares in the the conditional comparision are generated without error.\n\
2632 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.",
2633 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, int code, tree op0, tree op1),
2634 NULL)
2636 DEFHOOK
2637 (gen_ccmp_next,
2638 "This function prepares to emit a conditional comparison within a sequence\n\
2639 of conditional comparisons. It returns an appropriate comparison with\n\
2640 @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2641 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2642 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2643 compares in the conditional comparision are generated without error. The\n\
2644 @var{prev} expression is the result of a prior call to @code{gen_ccmp_first}\n\
2645 or @code{gen_ccmp_next}. It may return @code{NULL} if the combination of\n\
2646 @var{prev} and this comparison is not supported, otherwise the result must\n\
2647 be appropriate for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2648 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.\n\
2649 @var{bit_code} is @code{AND} or @code{IOR}, which is the op on the compares.",
2650 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, rtx prev, int cmp_code, tree op0, tree op1, int bit_code),
2651 NULL)
2653 /* Return a new value for loop unroll size. */
2654 DEFHOOK
2655 (loop_unroll_adjust,
2656 "This target hook returns a new value for the number of times @var{loop}\n\
2657 should be unrolled. The parameter @var{nunroll} is the number of times\n\
2658 the loop is to be unrolled. The parameter @var{loop} is a pointer to\n\
2659 the loop, which is going to be checked for unrolling. This target hook\n\
2660 is required only when the target has special constraints like maximum\n\
2661 number of memory accesses.",
2662 unsigned, (unsigned nunroll, struct loop *loop),
2663 NULL)
2665 /* True if X is a legitimate MODE-mode immediate operand. */
2666 DEFHOOK
2667 (legitimate_constant_p,
2668 "This hook returns true if @var{x} is a legitimate constant for a\n\
2669 @var{mode}-mode immediate operand on the target machine. You can assume that\n\
2670 @var{x} satisfies @code{CONSTANT_P}, so you need not check this.\n\
2672 The default definition returns true.",
2673 bool, (machine_mode mode, rtx x),
2674 hook_bool_mode_rtx_true)
2676 /* True if the constant X cannot be placed in the constant pool. */
2677 DEFHOOK
2678 (cannot_force_const_mem,
2679 "This hook should return true if @var{x} is of a form that cannot (or\n\
2680 should not) be spilled to the constant pool. @var{mode} is the mode\n\
2681 of @var{x}.\n\
2683 The default version of this hook returns false.\n\
2685 The primary reason to define this hook is to prevent reload from\n\
2686 deciding that a non-legitimate constant would be better reloaded\n\
2687 from the constant pool instead of spilling and reloading a register\n\
2688 holding the constant. This restriction is often true of addresses\n\
2689 of TLS symbols for various targets.",
2690 bool, (machine_mode mode, rtx x),
2691 hook_bool_mode_rtx_false)
2693 DEFHOOK_UNDOC
2694 (cannot_copy_insn_p,
2695 "True if the insn @var{x} cannot be duplicated.",
2696 bool, (rtx_insn *), NULL)
2698 /* True if X is considered to be commutative. */
2699 DEFHOOK
2700 (commutative_p,
2701 "This target hook returns @code{true} if @var{x} is considered to be commutative.\n\
2702 Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider\n\
2703 PLUS to be commutative inside a MEM@. @var{outer_code} is the rtx code\n\
2704 of the enclosing rtl, if known, otherwise it is UNKNOWN.",
2705 bool, (const_rtx x, int outer_code),
2706 hook_bool_const_rtx_commutative_p)
2708 /* True if ADDR is an address-expression whose effect depends
2709 on the mode of the memory reference it is used in. */
2710 DEFHOOK
2711 (mode_dependent_address_p,
2712 "This hook returns @code{true} if memory address @var{addr} in address\n\
2713 space @var{addrspace} can have\n\
2714 different meanings depending on the machine mode of the memory\n\
2715 reference it is used for or if the address is valid for some modes\n\
2716 but not others.\n\
2718 Autoincrement and autodecrement addresses typically have mode-dependent\n\
2719 effects because the amount of the increment or decrement is the size\n\
2720 of the operand being addressed. Some machines have other mode-dependent\n\
2721 addresses. Many RISC machines have no mode-dependent addresses.\n\
2723 You may assume that @var{addr} is a valid address for the machine.\n\
2725 The default version of this hook returns @code{false}.",
2726 bool, (const_rtx addr, addr_space_t addrspace),
2727 default_mode_dependent_address_p)
2729 /* Given an invalid address X for a given machine mode, try machine-specific
2730 ways to make it legitimate. Return X or an invalid address on failure. */
2731 DEFHOOK
2732 (legitimize_address,
2733 "This hook is given an invalid memory address @var{x} for an\n\
2734 operand of mode @var{mode} and should try to return a valid memory\n\
2735 address.\n\
2737 @findex break_out_memory_refs\n\
2738 @var{x} will always be the result of a call to @code{break_out_memory_refs},\n\
2739 and @var{oldx} will be the operand that was given to that function to produce\n\
2740 @var{x}.\n\
2742 The code of the hook should not alter the substructure of\n\
2743 @var{x}. If it transforms @var{x} into a more legitimate form, it\n\
2744 should return the new @var{x}.\n\
2746 It is not necessary for this hook to come up with a legitimate address,\n\
2747 with the exception of native TLS addresses (@pxref{Emulated TLS}).\n\
2748 The compiler has standard ways of doing so in all cases. In fact, if\n\
2749 the target supports only emulated TLS, it\n\
2750 is safe to omit this hook or make it return @var{x} if it cannot find\n\
2751 a valid way to legitimize the address. But often a machine-dependent\n\
2752 strategy can generate better code.",
2753 rtx, (rtx x, rtx oldx, machine_mode mode),
2754 default_legitimize_address)
2756 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
2757 DEFHOOK
2758 (delegitimize_address,
2759 "This hook is used to undo the possibly obfuscating effects of the\n\
2760 @code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target\n\
2761 macros. Some backend implementations of these macros wrap symbol\n\
2762 references inside an @code{UNSPEC} rtx to represent PIC or similar\n\
2763 addressing modes. This target hook allows GCC's optimizers to understand\n\
2764 the semantics of these opaque @code{UNSPEC}s by converting them back\n\
2765 into their original form.",
2766 rtx, (rtx x),
2767 delegitimize_mem_from_attrs)
2769 /* Given an RTX, return true if it is not ok to emit it into debug info
2770 section. */
2771 DEFHOOK
2772 (const_not_ok_for_debug_p,
2773 "This hook should return true if @var{x} should not be emitted into\n\
2774 debug sections.",
2775 bool, (rtx x),
2776 default_const_not_ok_for_debug_p)
2778 /* Given an address RTX, say whether it is valid. */
2779 DEFHOOK
2780 (legitimate_address_p,
2781 "A function that returns whether @var{x} (an RTX) is a legitimate memory\n\
2782 address on the target machine for a memory operand of mode @var{mode}.\n\
2784 Legitimate addresses are defined in two variants: a strict variant and a\n\
2785 non-strict one. The @var{strict} parameter chooses which variant is\n\
2786 desired by the caller.\n\
2788 The strict variant is used in the reload pass. It must be defined so\n\
2789 that any pseudo-register that has not been allocated a hard register is\n\
2790 considered a memory reference. This is because in contexts where some\n\
2791 kind of register is required, a pseudo-register with no hard register\n\
2792 must be rejected. For non-hard registers, the strict variant should look\n\
2793 up the @code{reg_renumber} array; it should then proceed using the hard\n\
2794 register number in the array, or treat the pseudo as a memory reference\n\
2795 if the array holds @code{-1}.\n\
2797 The non-strict variant is used in other passes. It must be defined to\n\
2798 accept all pseudo-registers in every context where some kind of\n\
2799 register is required.\n\
2801 Normally, constant addresses which are the sum of a @code{symbol_ref}\n\
2802 and an integer are stored inside a @code{const} RTX to mark them as\n\
2803 constant. Therefore, there is no need to recognize such sums\n\
2804 specifically as legitimate addresses. Normally you would simply\n\
2805 recognize any @code{const} as legitimate.\n\
2807 Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant\n\
2808 sums that are not marked with @code{const}. It assumes that a naked\n\
2809 @code{plus} indicates indexing. If so, then you @emph{must} reject such\n\
2810 naked constant sums as illegitimate addresses, so that none of them will\n\
2811 be given to @code{PRINT_OPERAND_ADDRESS}.\n\
2813 @cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation\n\
2814 On some machines, whether a symbolic address is legitimate depends on\n\
2815 the section that the address refers to. On these machines, define the\n\
2816 target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information\n\
2817 into the @code{symbol_ref}, and then check for it here. When you see a\n\
2818 @code{const}, you will have to look inside it to find the\n\
2819 @code{symbol_ref} in order to determine the section. @xref{Assembler\n\
2820 Format}.\n\
2822 @cindex @code{GO_IF_LEGITIMATE_ADDRESS}\n\
2823 Some ports are still using a deprecated legacy substitute for\n\
2824 this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro. This macro\n\
2825 has this syntax:\n\
2827 @example\n\
2828 #define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})\n\
2829 @end example\n\
2831 @noindent\n\
2832 and should @code{goto @var{label}} if the address @var{x} is a valid\n\
2833 address on the target machine for a memory operand of mode @var{mode}.\n\
2835 @findex REG_OK_STRICT\n\
2836 Compiler source files that want to use the strict variant of this\n\
2837 macro define the macro @code{REG_OK_STRICT}. You should use an\n\
2838 @code{#ifdef REG_OK_STRICT} conditional to define the strict variant in\n\
2839 that case and the non-strict variant otherwise.\n\
2841 Using the hook is usually simpler because it limits the number of\n\
2842 files that are recompiled when changes are made.",
2843 bool, (machine_mode mode, rtx x, bool strict),
2844 default_legitimate_address_p)
2846 /* True if the given constant can be put into an object_block. */
2847 DEFHOOK
2848 (use_blocks_for_constant_p,
2849 "This hook should return true if pool entries for constant @var{x} can\n\
2850 be placed in an @code{object_block} structure. @var{mode} is the mode\n\
2851 of @var{x}.\n\
2853 The default version returns false for all constants.",
2854 bool, (machine_mode mode, const_rtx x),
2855 hook_bool_mode_const_rtx_false)
2857 /* True if the given decl can be put into an object_block. */
2858 DEFHOOK
2859 (use_blocks_for_decl_p,
2860 "This hook should return true if pool entries for @var{decl} should\n\
2861 be placed in an @code{object_block} structure.\n\
2863 The default version returns true for all decls.",
2864 bool, (const_tree decl),
2865 hook_bool_const_tree_true)
2867 /* The minimum and maximum byte offsets for anchored addresses. */
2868 DEFHOOKPOD
2869 (min_anchor_offset,
2870 "The minimum offset that should be applied to a section anchor.\n\
2871 On most targets, it should be the smallest offset that can be\n\
2872 applied to a base register while still giving a legitimate address\n\
2873 for every mode. The default value is 0.",
2874 HOST_WIDE_INT, 0)
2876 DEFHOOKPOD
2877 (max_anchor_offset,
2878 "Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)\n\
2879 offset that should be applied to section anchors. The default\n\
2880 value is 0.",
2881 HOST_WIDE_INT, 0)
2883 /* True if section anchors can be used to access the given symbol. */
2884 DEFHOOK
2885 (use_anchors_for_symbol_p,
2886 "Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}\n\
2887 @var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and\n\
2888 @samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.\n\
2890 The default version is correct for most targets, but you might need to\n\
2891 intercept this hook to handle things like target-specific attributes\n\
2892 or target-specific sections.",
2893 bool, (const_rtx x),
2894 default_use_anchors_for_symbol_p)
2896 /* True if target supports indirect functions. */
2897 DEFHOOK
2898 (has_ifunc_p,
2899 "It returns true if the target supports GNU indirect functions.\n\
2900 The support includes the assembler, linker and dynamic linker.\n\
2901 The default value of this hook is based on target's libc.",
2902 bool, (void),
2903 default_has_ifunc_p)
2905 /* True if it is OK to do sibling call optimization for the specified
2906 call expression EXP. DECL will be the called function, or NULL if
2907 this is an indirect call. */
2908 DEFHOOK
2909 (function_ok_for_sibcall,
2910 "True if it is OK to do sibling call optimization for the specified\n\
2911 call expression @var{exp}. @var{decl} will be the called function,\n\
2912 or @code{NULL} if this is an indirect call.\n\
2914 It is not uncommon for limitations of calling conventions to prevent\n\
2915 tail calls to functions outside the current unit of translation, or\n\
2916 during PIC compilation. The hook is used to enforce these restrictions,\n\
2917 as the @code{sibcall} md pattern can not fail, or fall over to a\n\
2918 ``normal'' call. The criteria for successful sibling call optimization\n\
2919 may vary greatly between different architectures.",
2920 bool, (tree decl, tree exp),
2921 hook_bool_tree_tree_false)
2923 /* Establish appropriate back-end context for processing the function
2924 FNDECL. The argument might be NULL to indicate processing at top
2925 level, outside of any function scope. */
2926 DEFHOOK
2927 (set_current_function,
2928 "The compiler invokes this hook whenever it changes its current function\n\
2929 context (@code{cfun}). You can define this function if\n\
2930 the back end needs to perform any initialization or reset actions on a\n\
2931 per-function basis. For example, it may be used to implement function\n\
2932 attributes that affect register usage or code generation patterns.\n\
2933 The argument @var{decl} is the declaration for the new function context,\n\
2934 and may be null to indicate that the compiler has left a function context\n\
2935 and is returning to processing at the top level.\n\
2936 The default hook function does nothing.\n\
2938 GCC sets @code{cfun} to a dummy function context during initialization of\n\
2939 some parts of the back end. The hook function is not invoked in this\n\
2940 situation; you need not worry about the hook being invoked recursively,\n\
2941 or when the back end is in a partially-initialized state.\n\
2942 @code{cfun} might be @code{NULL} to indicate processing at top level,\n\
2943 outside of any function scope.",
2944 void, (tree decl), hook_void_tree)
2946 /* True if EXP should be placed in a "small data" section. */
2947 DEFHOOK
2948 (in_small_data_p,
2949 "Returns true if @var{exp} should be placed into a ``small data'' section.\n\
2950 The default version of this hook always returns false.",
2951 bool, (const_tree exp),
2952 hook_bool_const_tree_false)
2954 /* True if EXP names an object for which name resolution must resolve
2955 to the current executable or shared library. */
2956 DEFHOOK
2957 (binds_local_p,
2958 "Returns true if @var{exp} names an object for which name resolution\n\
2959 rules must resolve to the current ``module'' (dynamic shared library\n\
2960 or executable image).\n\
2962 The default version of this hook implements the name resolution rules\n\
2963 for ELF, which has a looser model of global name binding than other\n\
2964 currently supported object file formats.",
2965 bool, (const_tree exp),
2966 default_binds_local_p)
2968 /* Check if profiling code is before or after prologue. */
2969 DEFHOOK
2970 (profile_before_prologue,
2971 "It returns true if target wants profile code emitted before prologue.\n\n\
2972 The default version of this hook use the target macro\n\
2973 @code{PROFILE_BEFORE_PROLOGUE}.",
2974 bool, (void),
2975 default_profile_before_prologue)
2977 /* Return true if a leaf function should stay leaf even with profiling
2978 enabled. */
2979 DEFHOOK
2980 (keep_leaf_when_profiled,
2981 "This target hook returns true if the target wants the leaf flag for\
2982 the current function to stay true even if it calls mcount. This might\
2983 make sense for targets using the leaf flag only to determine whether a\
2984 stack frame needs to be generated or not and for which the call to\
2985 mcount is generated before the function prologue.",
2986 bool, (void),
2987 default_keep_leaf_when_profiled)
2989 /* Modify and return the identifier of a DECL's external name,
2990 originally identified by ID, as required by the target,
2991 (eg, append @nn to windows32 stdcall function names).
2992 The default is to return ID without modification. */
2993 DEFHOOK
2994 (mangle_decl_assembler_name,
2995 "Define this hook if you need to postprocess the assembler name generated\n\
2996 by target-independent code. The @var{id} provided to this hook will be\n\
2997 the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,\n\
2998 or the mangled name of the @var{decl} in C++). The return value of the\n\
2999 hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on\n\
3000 your target system. The default implementation of this hook just\n\
3001 returns the @var{id} provided.",
3002 tree, (tree decl, tree id),
3003 default_mangle_decl_assembler_name)
3005 /* Do something target-specific to record properties of the DECL into
3006 the associated SYMBOL_REF. */
3007 DEFHOOK
3008 (encode_section_info,
3009 "Define this hook if references to a symbol or a constant must be\n\
3010 treated differently depending on something about the variable or\n\
3011 function named by the symbol (such as what section it is in).\n\
3013 The hook is executed immediately after rtl has been created for\n\
3014 @var{decl}, which may be a variable or function declaration or\n\
3015 an entry in the constant pool. In either case, @var{rtl} is the\n\
3016 rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}\n\
3017 in this hook; that field may not have been initialized yet.\n\
3019 In the case of a constant, it is safe to assume that the rtl is\n\
3020 a @code{mem} whose address is a @code{symbol_ref}. Most decls\n\
3021 will also have this form, but that is not guaranteed. Global\n\
3022 register variables, for instance, will have a @code{reg} for their\n\
3023 rtl. (Normally the right thing to do with such unusual rtl is\n\
3024 leave it alone.)\n\
3026 The @var{new_decl_p} argument will be true if this is the first time\n\
3027 that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will\n\
3028 be false for subsequent invocations, which will happen for duplicate\n\
3029 declarations. Whether or not anything must be done for the duplicate\n\
3030 declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.\n\
3031 @var{new_decl_p} is always true when the hook is called for a constant.\n\
3033 @cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}\n\
3034 The usual thing for this hook to do is to record flags in the\n\
3035 @code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.\n\
3036 Historically, the name string was modified if it was necessary to\n\
3037 encode more than one bit of information, but this practice is now\n\
3038 discouraged; use @code{SYMBOL_REF_FLAGS}.\n\
3040 The default definition of this hook, @code{default_encode_section_info}\n\
3041 in @file{varasm.c}, sets a number of commonly-useful bits in\n\
3042 @code{SYMBOL_REF_FLAGS}. Check whether the default does what you need\n\
3043 before overriding it.",
3044 void, (tree decl, rtx rtl, int new_decl_p),
3045 default_encode_section_info)
3047 /* Undo the effects of encode_section_info on the symbol string. */
3048 DEFHOOK
3049 (strip_name_encoding,
3050 "Decode @var{name} and return the real name part, sans\n\
3051 the characters that @code{TARGET_ENCODE_SECTION_INFO}\n\
3052 may have added.",
3053 const char *, (const char *name),
3054 default_strip_name_encoding)
3056 /* If shift optabs for MODE are known to always truncate the shift count,
3057 return the mask that they apply. Return 0 otherwise. */
3058 DEFHOOK
3059 (shift_truncation_mask,
3060 "This function describes how the standard shift patterns for @var{mode}\n\
3061 deal with shifts by negative amounts or by more than the width of the mode.\n\
3062 @xref{shift patterns}.\n\
3064 On many machines, the shift patterns will apply a mask @var{m} to the\n\
3065 shift count, meaning that a fixed-width shift of @var{x} by @var{y} is\n\
3066 equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If\n\
3067 this is true for mode @var{mode}, the function should return @var{m},\n\
3068 otherwise it should return 0. A return value of 0 indicates that no\n\
3069 particular behavior is guaranteed.\n\
3071 Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does\n\
3072 @emph{not} apply to general shift rtxes; it applies only to instructions\n\
3073 that are generated by the named shift patterns.\n\
3075 The default implementation of this function returns\n\
3076 @code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}\n\
3077 and 0 otherwise. This definition is always safe, but if\n\
3078 @code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns\n\
3079 nevertheless truncate the shift count, you may get better code\n\
3080 by overriding it.",
3081 unsigned HOST_WIDE_INT, (machine_mode mode),
3082 default_shift_truncation_mask)
3084 /* Return the number of divisions in the given MODE that should be present,
3085 so that it is profitable to turn the division into a multiplication by
3086 the reciprocal. */
3087 DEFHOOK
3088 (min_divisions_for_recip_mul,
3089 "When @option{-ffast-math} is in effect, GCC tries to optimize\n\
3090 divisions by the same divisor, by turning them into multiplications by\n\
3091 the reciprocal. This target hook specifies the minimum number of divisions\n\
3092 that should be there for GCC to perform the optimization for a variable\n\
3093 of mode @var{mode}. The default implementation returns 3 if the machine\n\
3094 has an instruction for the division, and 2 if it does not.",
3095 unsigned int, (machine_mode mode),
3096 default_min_divisions_for_recip_mul)
3098 DEFHOOK
3099 (truly_noop_truncation,
3100 "This hook returns true if it is safe to ``convert'' a value of\n\
3101 @var{inprec} bits to one of @var{outprec} bits (where @var{outprec} is\n\
3102 smaller than @var{inprec}) by merely operating on it as if it had only\n\
3103 @var{outprec} bits. The default returns true unconditionally, which\n\
3104 is correct for most machines.\n\
3106 If @code{TARGET_MODES_TIEABLE_P} returns false for a pair of modes,\n\
3107 suboptimal code can result if this hook returns true for the corresponding\n\
3108 mode sizes. Making this hook return false in such cases may improve things.",
3109 bool, (poly_uint64 outprec, poly_uint64 inprec),
3110 hook_bool_puint64_puint64_true)
3112 /* If the representation of integral MODE is such that values are
3113 always sign-extended to a wider mode MODE_REP then return
3114 SIGN_EXTEND. Return UNKNOWN otherwise. */
3115 /* Note that the return type ought to be RTX_CODE, but that's not
3116 necessarily defined at this point. */
3117 DEFHOOK
3118 (mode_rep_extended,
3119 "The representation of an integral mode can be such that the values\n\
3120 are always extended to a wider integral mode. Return\n\
3121 @code{SIGN_EXTEND} if values of @var{mode} are represented in\n\
3122 sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}\n\
3123 otherwise. (Currently, none of the targets use zero-extended\n\
3124 representation this way so unlike @code{LOAD_EXTEND_OP},\n\
3125 @code{TARGET_MODE_REP_EXTENDED} is expected to return either\n\
3126 @code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends\n\
3127 @var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next\n\
3128 widest integral mode and currently we take advantage of this fact.)\n\
3130 Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}\n\
3131 value even if the extension is not performed on certain hard registers\n\
3132 as long as for the @code{REGNO_REG_CLASS} of these hard registers\n\
3133 @code{TARGET_CAN_CHANGE_MODE_CLASS} returns false.\n\
3135 Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}\n\
3136 describe two related properties. If you define\n\
3137 @code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want\n\
3138 to define @code{LOAD_EXTEND_OP (mode)} to return the same type of\n\
3139 extension.\n\
3141 In order to enforce the representation of @code{mode},\n\
3142 @code{TARGET_TRULY_NOOP_TRUNCATION} should return false when truncating to\n\
3143 @code{mode}.",
3144 int, (scalar_int_mode mode, scalar_int_mode rep_mode),
3145 default_mode_rep_extended)
3147 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
3148 DEFHOOK
3149 (valid_pointer_mode,
3150 "Define this to return nonzero if the port can handle pointers\n\
3151 with machine mode @var{mode}. The default version of this\n\
3152 hook returns true for both @code{ptr_mode} and @code{Pmode}.",
3153 bool, (scalar_int_mode mode),
3154 default_valid_pointer_mode)
3156 /* Disambiguate with errno. */
3157 DEFHOOK
3158 (ref_may_alias_errno,
3159 "Define this to return nonzero if the memory reference @var{ref}\
3160 may alias with the system C library errno location. The default\
3161 version of this hook assumes the system C library errno location\
3162 is either a declaration of type int or accessed by dereferencing\
3163 a pointer to int.",
3164 bool, (struct ao_ref *ref),
3165 default_ref_may_alias_errno)
3167 /* Support for named address spaces. */
3168 #undef HOOK_PREFIX
3169 #define HOOK_PREFIX "TARGET_ADDR_SPACE_"
3170 HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)
3172 /* MODE to use for a pointer into another address space. */
3173 DEFHOOK
3174 (pointer_mode,
3175 "Define this to return the machine mode to use for pointers to\n\
3176 @var{address_space} if the target supports named address spaces.\n\
3177 The default version of this hook returns @code{ptr_mode}.",
3178 scalar_int_mode, (addr_space_t address_space),
3179 default_addr_space_pointer_mode)
3181 /* MODE to use for an address in another address space. */
3182 DEFHOOK
3183 (address_mode,
3184 "Define this to return the machine mode to use for addresses in\n\
3185 @var{address_space} if the target supports named address spaces.\n\
3186 The default version of this hook returns @code{Pmode}.",
3187 scalar_int_mode, (addr_space_t address_space),
3188 default_addr_space_address_mode)
3190 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
3191 in another address space. */
3192 DEFHOOK
3193 (valid_pointer_mode,
3194 "Define this to return nonzero if the port can handle pointers\n\
3195 with machine mode @var{mode} to address space @var{as}. This target\n\
3196 hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,\n\
3197 except that it includes explicit named address space support. The default\n\
3198 version of this hook returns true for the modes returned by either the\n\
3199 @code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}\n\
3200 target hooks for the given address space.",
3201 bool, (scalar_int_mode mode, addr_space_t as),
3202 default_addr_space_valid_pointer_mode)
3204 /* True if an address is a valid memory address to a given named address
3205 space for a given mode. */
3206 DEFHOOK
3207 (legitimate_address_p,
3208 "Define this to return true if @var{exp} is a valid address for mode\n\
3209 @var{mode} in the named address space @var{as}. The @var{strict}\n\
3210 parameter says whether strict addressing is in effect after reload has\n\
3211 finished. This target hook is the same as the\n\
3212 @code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes\n\
3213 explicit named address space support.",
3214 bool, (machine_mode mode, rtx exp, bool strict, addr_space_t as),
3215 default_addr_space_legitimate_address_p)
3217 /* Return an updated address to convert an invalid pointer to a named
3218 address space to a valid one. If NULL_RTX is returned use machine
3219 independent methods to make the address valid. */
3220 DEFHOOK
3221 (legitimize_address,
3222 "Define this to modify an invalid address @var{x} to be a valid address\n\
3223 with mode @var{mode} in the named address space @var{as}. This target\n\
3224 hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,\n\
3225 except that it includes explicit named address space support.",
3226 rtx, (rtx x, rtx oldx, machine_mode mode, addr_space_t as),
3227 default_addr_space_legitimize_address)
3229 /* True if one named address space is a subset of another named address. */
3230 DEFHOOK
3231 (subset_p,
3232 "Define this to return whether the @var{subset} named address space is\n\
3233 contained within the @var{superset} named address space. Pointers to\n\
3234 a named address space that is a subset of another named address space\n\
3235 will be converted automatically without a cast if used together in\n\
3236 arithmetic operations. Pointers to a superset address space can be\n\
3237 converted to pointers to a subset address space via explicit casts.",
3238 bool, (addr_space_t subset, addr_space_t superset),
3239 default_addr_space_subset_p)
3241 /* True if 0 is a valid address in the address space, or false if
3242 0 is a NULL in the address space. */
3243 DEFHOOK
3244 (zero_address_valid,
3245 "Define this to modify the default handling of address 0 for the\n\
3246 address space. Return true if 0 should be considered a valid address.",
3247 bool, (addr_space_t as),
3248 default_addr_space_zero_address_valid)
3250 /* Function to convert an rtl expression from one address space to another. */
3251 DEFHOOK
3252 (convert,
3253 "Define this to convert the pointer expression represented by the RTL\n\
3254 @var{op} with type @var{from_type} that points to a named address\n\
3255 space to a new pointer expression with type @var{to_type} that points\n\
3256 to a different named address space. When this hook it called, it is\n\
3257 guaranteed that one of the two address spaces is a subset of the other,\n\
3258 as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.",
3259 rtx, (rtx op, tree from_type, tree to_type),
3260 default_addr_space_convert)
3262 /* Function to encode an address space into dwarf. */
3263 DEFHOOK
3264 (debug,
3265 "Define this to define how the address space is encoded in dwarf.\n\
3266 The result is the value to be used with @code{DW_AT_address_class}.",
3267 int, (addr_space_t as),
3268 default_addr_space_debug)
3270 /* Function to emit custom diagnostic if an address space is used. */
3271 DEFHOOK
3272 (diagnose_usage,
3273 "Define this hook if the availability of an address space depends on\n\
3274 command line options and some diagnostics should be printed when the\n\
3275 address space is used. This hook is called during parsing and allows\n\
3276 to emit a better diagnostic compared to the case where the address space\n\
3277 was not registered with @code{c_register_addr_space}. @var{as} is\n\
3278 the address space as registered with @code{c_register_addr_space}.\n\
3279 @var{loc} is the location of the address space qualifier token.\n\
3280 The default implementation does nothing.",
3281 void, (addr_space_t as, location_t loc),
3282 default_addr_space_diagnose_usage)
3284 HOOK_VECTOR_END (addr_space)
3286 #undef HOOK_PREFIX
3287 #define HOOK_PREFIX "TARGET_"
3289 DEFHOOK
3290 (static_rtx_alignment,
3291 "This hook returns the preferred alignment in bits for a\n\
3292 statically-allocated rtx, such as a constant pool entry. @var{mode}\n\
3293 is the mode of the rtx. The default implementation returns\n\
3294 @samp{GET_MODE_ALIGNMENT (@var{mode})}.",
3295 HOST_WIDE_INT, (machine_mode mode),
3296 default_static_rtx_alignment)
3298 DEFHOOK
3299 (constant_alignment,
3300 "This hook returns the alignment in bits of a constant that is being\n\
3301 placed in memory. @var{constant} is the constant and @var{basic_align}\n\
3302 is the alignment that the object would ordinarily have.\n\
3304 The default definition just returns @var{basic_align}.\n\
3306 The typical use of this hook is to increase alignment for string\n\
3307 constants to be word aligned so that @code{strcpy} calls that copy\n\
3308 constants can be done inline. The function\n\
3309 @code{constant_alignment_word_strings} provides such a definition.",
3310 HOST_WIDE_INT, (const_tree constant, HOST_WIDE_INT basic_align),
3311 default_constant_alignment)
3313 /* True if MODE is valid for the target. By "valid", we mean able to
3314 be manipulated in non-trivial ways. In particular, this means all
3315 the arithmetic is supported. */
3316 DEFHOOK
3317 (scalar_mode_supported_p,
3318 "Define this to return nonzero if the port is prepared to handle\n\
3319 insns involving scalar mode @var{mode}. For a scalar mode to be\n\
3320 considered supported, all the basic arithmetic and comparisons\n\
3321 must work.\n\
3323 The default version of this hook returns true for any mode\n\
3324 required to handle the basic C types (as defined by the port).\n\
3325 Included here are the double-word arithmetic supported by the\n\
3326 code in @file{optabs.c}.",
3327 bool, (scalar_mode mode),
3328 default_scalar_mode_supported_p)
3330 /* Similarly for vector modes. "Supported" here is less strict. At
3331 least some operations are supported; need to check optabs or builtins
3332 for further details. */
3333 DEFHOOK
3334 (vector_mode_supported_p,
3335 "Define this to return nonzero if the port is prepared to handle\n\
3336 insns involving vector mode @var{mode}. At the very least, it\n\
3337 must have move patterns for this mode.",
3338 bool, (machine_mode mode),
3339 hook_bool_mode_false)
3341 DEFHOOK
3342 (vector_alignment,
3343 "This hook can be used to define the alignment for a vector of type\n\
3344 @var{type}, in order to comply with a platform ABI. The default is to\n\
3345 require natural alignment for vector types. The alignment returned by\n\
3346 this hook must be a power-of-two multiple of the default alignment of\n\
3347 the vector element type.",
3348 HOST_WIDE_INT, (const_tree type),
3349 default_vector_alignment)
3351 DEFHOOK
3352 (array_mode,
3353 "Return the mode that GCC should use for an array that has\n\
3354 @var{nelems} elements, with each element having mode @var{mode}.\n\
3355 Return no mode if the target has no special requirements. In the\n\
3356 latter case, GCC looks for an integer mode of the appropriate size\n\
3357 if available and uses BLKmode otherwise. Usually the search for the\n\
3358 integer mode is limited to @code{MAX_FIXED_MODE_SIZE}, but the\n\
3359 @code{TARGET_ARRAY_MODE_SUPPORTED_P} hook allows a larger mode to be\n\
3360 used in specific cases.\n\
3362 The main use of this hook is to specify that an array of vectors should\n\
3363 also have a vector mode. The default implementation returns no mode.",
3364 opt_machine_mode, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3365 hook_optmode_mode_uhwi_none)
3367 /* True if we should try to use a scalar mode to represent an array,
3368 overriding the usual MAX_FIXED_MODE limit. */
3369 DEFHOOK
3370 (array_mode_supported_p,
3371 "Return true if GCC should try to use a scalar mode to store an array\n\
3372 of @var{nelems} elements, given that each element has mode @var{mode}.\n\
3373 Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
3374 and allows GCC to use any defined integer mode.\n\
3376 One use of this hook is to support vector load and store operations\n\
3377 that operate on several homogeneous vectors. For example, ARM NEON\n\
3378 has operations like:\n\
3380 @smallexample\n\
3381 int8x8x3_t vld3_s8 (const int8_t *)\n\
3382 @end smallexample\n\
3384 where the return type is defined as:\n\
3386 @smallexample\n\
3387 typedef struct int8x8x3_t\n\
3388 @{\n\
3389 int8x8_t val[3];\n\
3390 @} int8x8x3_t;\n\
3391 @end smallexample\n\
3393 If this hook allows @code{val} to have a scalar mode, then\n\
3394 @code{int8x8x3_t} can have the same mode. GCC can then store\n\
3395 @code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
3396 bool, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3397 hook_bool_mode_uhwi_false)
3399 DEFHOOK
3400 (libgcc_floating_mode_supported_p,
3401 "Define this to return nonzero if libgcc provides support for the \n\
3402 floating-point mode @var{mode}, which is known to pass \n\
3403 @code{TARGET_SCALAR_MODE_SUPPORTED_P}. The default version of this \n\
3404 hook returns true for all of @code{SFmode}, @code{DFmode}, \n\
3405 @code{XFmode} and @code{TFmode}, if such modes exist.",
3406 bool, (scalar_float_mode mode),
3407 default_libgcc_floating_mode_supported_p)
3409 DEFHOOK
3410 (floatn_mode,
3411 "Define this to return the machine mode to use for the type \n\
3412 @code{_Float@var{n}}, if @var{extended} is false, or the type \n\
3413 @code{_Float@var{n}x}, if @var{extended} is true. If such a type is not\n\
3414 supported, return @code{opt_scalar_float_mode ()}. The default version of\n\
3415 this hook returns @code{SFmode} for @code{_Float32}, @code{DFmode} for\n\
3416 @code{_Float64} and @code{_Float32x} and @code{TFmode} for \n\
3417 @code{_Float128}, if those modes exist and satisfy the requirements for \n\
3418 those types and pass @code{TARGET_SCALAR_MODE_SUPPORTED_P} and \n\
3419 @code{TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P}; for @code{_Float64x}, it \n\
3420 returns the first of @code{XFmode} and @code{TFmode} that exists and \n\
3421 satisfies the same requirements; for other types, it returns \n\
3422 @code{opt_scalar_float_mode ()}. The hook is only called for values\n\
3423 of @var{n} and @var{extended} that are valid according to\n\
3424 ISO/IEC TS 18661-3:2015; that is, @var{n} is one of 32, 64, 128, or,\n\
3425 if @var{extended} is false, 16 or greater than 128 and a multiple of 32.",
3426 opt_scalar_float_mode, (int n, bool extended),
3427 default_floatn_mode)
3429 DEFHOOK
3430 (floatn_builtin_p,
3431 "Define this to return true if the @code{_Float@var{n}} and\n\
3432 @code{_Float@var{n}x} built-in functions should implicitly enable the\n\
3433 built-in function without the @code{__builtin_} prefix in addition to the\n\
3434 normal built-in function with the @code{__builtin_} prefix. The default is\n\
3435 to only enable built-in functions without the @code{__builtin_} prefix for\n\
3436 the GNU C langauge. In strict ANSI/ISO mode, the built-in function without\n\
3437 the @code{__builtin_} prefix is not enabled. The argument @code{FUNC} is the\n\
3438 @code{enum built_in_function} id of the function to be enabled.",
3439 bool, (int func),
3440 default_floatn_builtin_p)
3442 /* Compute cost of moving data from a register of class FROM to one of
3443 TO, using MODE. */
3444 DEFHOOK
3445 (register_move_cost,
3446 "This target hook should return the cost of moving data of mode @var{mode}\n\
3447 from a register in class @var{from} to one in class @var{to}. The classes\n\
3448 are expressed using the enumeration values such as @code{GENERAL_REGS}.\n\
3449 A value of 2 is the default; other values are interpreted relative to\n\
3450 that.\n\
3452 It is not required that the cost always equal 2 when @var{from} is the\n\
3453 same as @var{to}; on some machines it is expensive to move between\n\
3454 registers if they are not general registers.\n\
3456 If reload sees an insn consisting of a single @code{set} between two\n\
3457 hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their\n\
3458 classes returns a value of 2, reload does not check to ensure that the\n\
3459 constraints of the insn are met. Setting a cost of other than 2 will\n\
3460 allow reload to verify that the constraints are met. You should do this\n\
3461 if the @samp{mov@var{m}} pattern's constraints do not allow such copying.\n\
3463 The default version of this function returns 2.",
3464 int, (machine_mode mode, reg_class_t from, reg_class_t to),
3465 default_register_move_cost)
3467 /* Compute cost of moving registers to/from memory. */
3468 /* ??? Documenting the argument types for this hook requires a GFDL
3469 license grant. Also, the documentation uses a different name for RCLASS. */
3470 DEFHOOK
3471 (memory_move_cost,
3472 "This target hook should return the cost of moving data of mode @var{mode}\n\
3473 between a register of class @var{rclass} and memory; @var{in} is @code{false}\n\
3474 if the value is to be written to memory, @code{true} if it is to be read in.\n\
3475 This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.\n\
3476 If moving between registers and memory is more expensive than between two\n\
3477 registers, you should add this target hook to express the relative cost.\n\
3479 If you do not add this target hook, GCC uses a default cost of 4 plus\n\
3480 the cost of copying via a secondary reload register, if one is\n\
3481 needed. If your machine requires a secondary reload register to copy\n\
3482 between memory and a register of @var{rclass} but the reload mechanism is\n\
3483 more complex than copying via an intermediate, use this target hook to\n\
3484 reflect the actual cost of the move.\n\
3486 GCC defines the function @code{memory_move_secondary_cost} if\n\
3487 secondary reloads are needed. It computes the costs due to copying via\n\
3488 a secondary register. If your machine copies from memory using a\n\
3489 secondary register in the conventional way but the default base value of\n\
3490 4 is not correct for your machine, use this target hook to add some other\n\
3491 value to the result of that function. The arguments to that function\n\
3492 are the same as to this target hook.",
3493 int, (machine_mode mode, reg_class_t rclass, bool in),
3494 default_memory_move_cost)
3496 DEFHOOK
3497 (use_by_pieces_infrastructure_p,
3498 "GCC will attempt several strategies when asked to copy between\n\
3499 two areas of memory, or to set, clear or store to memory, for example\n\
3500 when copying a @code{struct}. The @code{by_pieces} infrastructure\n\
3501 implements such memory operations as a sequence of load, store or move\n\
3502 insns. Alternate strategies are to expand the\n\
3503 @code{movmem} or @code{setmem} optabs, to emit a library call, or to emit\n\
3504 unit-by-unit, loop-based operations.\n\
3506 This target hook should return true if, for a memory operation with a\n\
3507 given @var{size} and @var{alignment}, using the @code{by_pieces}\n\
3508 infrastructure is expected to result in better code generation.\n\
3509 Both @var{size} and @var{alignment} are measured in terms of storage\n\
3510 units.\n\
3512 The parameter @var{op} is one of: @code{CLEAR_BY_PIECES},\n\
3513 @code{MOVE_BY_PIECES}, @code{SET_BY_PIECES}, @code{STORE_BY_PIECES} or\n\
3514 @code{COMPARE_BY_PIECES}. These describe the type of memory operation\n\
3515 under consideration.\n\
3517 The parameter @var{speed_p} is true if the code is currently being\n\
3518 optimized for speed rather than size.\n\
3520 Returning true for higher values of @var{size} can improve code generation\n\
3521 for speed if the target does not provide an implementation of the\n\
3522 @code{movmem} or @code{setmem} standard names, if the @code{movmem} or\n\
3523 @code{setmem} implementation would be more expensive than a sequence of\n\
3524 insns, or if the overhead of a library call would dominate that of\n\
3525 the body of the memory operation.\n\
3527 Returning true for higher values of @code{size} may also cause an increase\n\
3528 in code size, for example where the number of insns emitted to perform a\n\
3529 move would be greater than that of a library call.",
3530 bool, (unsigned HOST_WIDE_INT size, unsigned int alignment,
3531 enum by_pieces_operation op, bool speed_p),
3532 default_use_by_pieces_infrastructure_p)
3534 DEFHOOK
3535 (compare_by_pieces_branch_ratio,
3536 "When expanding a block comparison in MODE, gcc can try to reduce the\n\
3537 number of branches at the expense of more memory operations. This hook\n\
3538 allows the target to override the default choice. It should return the\n\
3539 factor by which branches should be reduced over the plain expansion with\n\
3540 one comparison per @var{mode}-sized piece. A port can also prevent a\n\
3541 particular mode from being used for block comparisons by returning a\n\
3542 negative number from this hook.",
3543 int, (machine_mode mode),
3544 default_compare_by_pieces_branch_ratio)
3546 DEFHOOK
3547 (slow_unaligned_access,
3548 "This hook returns true if memory accesses described by the\n\
3549 @var{mode} and @var{alignment} parameters have a cost many times greater\n\
3550 than aligned accesses, for example if they are emulated in a trap handler.\n\
3551 This hook is invoked only for unaligned accesses, i.e. when\n\
3552 @code{@var{alignment} < GET_MODE_ALIGNMENT (@var{mode})}.\n\
3554 When this hook returns true, the compiler will act as if\n\
3555 @code{STRICT_ALIGNMENT} were true when generating code for block\n\
3556 moves. This can cause significantly more instructions to be produced.\n\
3557 Therefore, do not make this hook return true if unaligned accesses only\n\
3558 add a cycle or two to the time for a memory access.\n\
3560 The hook must return true whenever @code{STRICT_ALIGNMENT} is true.\n\
3561 The default implementation returns @code{STRICT_ALIGNMENT}.",
3562 bool, (machine_mode mode, unsigned int align),
3563 default_slow_unaligned_access)
3565 DEFHOOK
3566 (optab_supported_p,
3567 "Return true if the optimizers should use optab @var{op} with\n\
3568 modes @var{mode1} and @var{mode2} for optimization type @var{opt_type}.\n\
3569 The optab is known to have an associated @file{.md} instruction\n\
3570 whose C condition is true. @var{mode2} is only meaningful for conversion\n\
3571 optabs; for direct optabs it is a copy of @var{mode1}.\n\
3573 For example, when called with @var{op} equal to @code{rint_optab} and\n\
3574 @var{mode1} equal to @code{DFmode}, the hook should say whether the\n\
3575 optimizers should use optab @code{rintdf2}.\n\
3577 The default hook returns true for all inputs.",
3578 bool, (int op, machine_mode mode1, machine_mode mode2,
3579 optimization_type opt_type),
3580 default_optab_supported_p)
3582 /* True for MODE if the target expects that registers in this mode will
3583 be allocated to registers in a small register class. The compiler is
3584 allowed to use registers explicitly used in the rtl as spill registers
3585 but it should prevent extending the lifetime of these registers. */
3586 DEFHOOK
3587 (small_register_classes_for_mode_p,
3588 "Define this to return nonzero for machine modes for which the port has\n\
3589 small register classes. If this target hook returns nonzero for a given\n\
3590 @var{mode}, the compiler will try to minimize the lifetime of registers\n\
3591 in @var{mode}. The hook may be called with @code{VOIDmode} as argument.\n\
3592 In this case, the hook is expected to return nonzero if it returns nonzero\n\
3593 for any mode.\n\
3595 On some machines, it is risky to let hard registers live across arbitrary\n\
3596 insns. Typically, these machines have instructions that require values\n\
3597 to be in specific registers (like an accumulator), and reload will fail\n\
3598 if the required hard register is used for another purpose across such an\n\
3599 insn.\n\
3601 Passes before reload do not know which hard registers will be used\n\
3602 in an instruction, but the machine modes of the registers set or used in\n\
3603 the instruction are already known. And for some machines, register\n\
3604 classes are small for, say, integer registers but not for floating point\n\
3605 registers. For example, the AMD x86-64 architecture requires specific\n\
3606 registers for the legacy x86 integer instructions, but there are many\n\
3607 SSE registers for floating point operations. On such targets, a good\n\
3608 strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}\n\
3609 machine modes but zero for the SSE register classes.\n\
3611 The default version of this hook returns false for any mode. It is always\n\
3612 safe to redefine this hook to return with a nonzero value. But if you\n\
3613 unnecessarily define it, you will reduce the amount of optimizations\n\
3614 that can be performed in some cases. If you do not define this hook\n\
3615 to return a nonzero value when it is required, the compiler will run out\n\
3616 of spill registers and print a fatal error message.",
3617 bool, (machine_mode mode),
3618 hook_bool_mode_false)
3620 /* Register number for a flags register. Only needs to be defined if the
3621 target is constrainted to use post-reload comparison elimination. */
3622 DEFHOOKPOD
3623 (flags_regnum,
3624 "If the target has a dedicated flags register, and it needs to use the\
3625 post-reload comparison elimination pass, then this value should be set\
3626 appropriately.",
3627 unsigned int, INVALID_REGNUM)
3629 /* Compute a (partial) cost for rtx X. Return true if the complete
3630 cost has been computed, and false if subexpressions should be
3631 scanned. In either case, *TOTAL contains the cost result. */
3632 /* Note that OUTER_CODE ought to be RTX_CODE, but that's
3633 not necessarily defined at this point. */
3634 DEFHOOK
3635 (rtx_costs,
3636 "This target hook describes the relative costs of RTL expressions.\n\
3638 The cost may depend on the precise form of the expression, which is\n\
3639 available for examination in @var{x}, and the fact that @var{x} appears\n\
3640 as operand @var{opno} of an expression with rtx code @var{outer_code}.\n\
3641 That is, the hook can assume that there is some rtx @var{y} such\n\
3642 that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that\n\
3643 either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or\n\
3644 (b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.\n\
3646 @var{mode} is @var{x}'s machine mode, or for cases like @code{const_int} that\n\
3647 do not have a mode, the mode in which @var{x} is used.\n\
3649 In implementing this hook, you can use the construct\n\
3650 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3651 instructions.\n\
3653 On entry to the hook, @code{*@var{total}} contains a default estimate\n\
3654 for the cost of the expression. The hook should modify this value as\n\
3655 necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}\n\
3656 for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus\n\
3657 operations, and @code{COSTS_N_INSNS (1)} for all other operations.\n\
3659 When optimizing for code size, i.e.@: when @code{speed} is\n\
3660 false, this target hook should be used to estimate the relative\n\
3661 size cost of an expression, again relative to @code{COSTS_N_INSNS}.\n\
3663 The hook returns true when all subexpressions of @var{x} have been\n\
3664 processed, and false when @code{rtx_cost} should recurse.",
3665 bool, (rtx x, machine_mode mode, int outer_code, int opno, int *total, bool speed),
3666 hook_bool_rtx_mode_int_int_intp_bool_false)
3668 /* Compute the cost of X, used as an address. Never called with
3669 invalid addresses. */
3670 DEFHOOK
3671 (address_cost,
3672 "This hook computes the cost of an addressing mode that contains\n\
3673 @var{address}. If not defined, the cost is computed from\n\
3674 the @var{address} expression and the @code{TARGET_RTX_COST} hook.\n\
3676 For most CISC machines, the default cost is a good approximation of the\n\
3677 true cost of the addressing mode. However, on RISC machines, all\n\
3678 instructions normally have the same length and execution time. Hence\n\
3679 all addresses will have equal costs.\n\
3681 In cases where more than one form of an address is known, the form with\n\
3682 the lowest cost will be used. If multiple forms have the same, lowest,\n\
3683 cost, the one that is the most complex will be used.\n\
3685 For example, suppose an address that is equal to the sum of a register\n\
3686 and a constant is used twice in the same basic block. When this macro\n\
3687 is not defined, the address will be computed in a register and memory\n\
3688 references will be indirect through that register. On machines where\n\
3689 the cost of the addressing mode containing the sum is no higher than\n\
3690 that of a simple indirect reference, this will produce an additional\n\
3691 instruction and possibly require an additional register. Proper\n\
3692 specification of this macro eliminates this overhead for such machines.\n\
3694 This hook is never called with an invalid address.\n\
3696 On machines where an address involving more than one register is as\n\
3697 cheap as an address computation involving only one register, defining\n\
3698 @code{TARGET_ADDRESS_COST} to reflect this can cause two registers to\n\
3699 be live over a region of code where only one would have been if\n\
3700 @code{TARGET_ADDRESS_COST} were not defined in that manner. This effect\n\
3701 should be considered in the definition of this macro. Equivalent costs\n\
3702 should probably only be given to addresses with different numbers of\n\
3703 registers on machines with lots of registers.",
3704 int, (rtx address, machine_mode mode, addr_space_t as, bool speed),
3705 default_address_cost)
3707 /* Compute a cost for INSN. */
3708 DEFHOOK
3709 (insn_cost,
3710 "This target hook describes the relative costs of RTL instructions.\n\
3712 In implementing this hook, you can use the construct\n\
3713 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3714 instructions.\n\
3716 When optimizing for code size, i.e.@: when @code{speed} is\n\
3717 false, this target hook should be used to estimate the relative\n\
3718 size cost of an expression, again relative to @code{COSTS_N_INSNS}.",
3719 int, (rtx_insn *insn, bool speed), NULL)
3721 /* Give a cost, in RTX Costs units, for an edge. Like BRANCH_COST, but with
3722 well defined units. */
3723 DEFHOOK
3724 (max_noce_ifcvt_seq_cost,
3725 "This hook returns a value in the same units as @code{TARGET_RTX_COSTS},\n\
3726 giving the maximum acceptable cost for a sequence generated by the RTL\n\
3727 if-conversion pass when conditional execution is not available.\n\
3728 The RTL if-conversion pass attempts to convert conditional operations\n\
3729 that would require a branch to a series of unconditional operations and\n\
3730 @code{mov@var{mode}cc} insns. This hook returns the maximum cost of the\n\
3731 unconditional instructions and the @code{mov@var{mode}cc} insns.\n\
3732 RTL if-conversion is cancelled if the cost of the converted sequence\n\
3733 is greater than the value returned by this hook.\n\
3735 @code{e} is the edge between the basic block containing the conditional\n\
3736 branch to the basic block which would be executed if the condition\n\
3737 were true.\n\
3739 The default implementation of this hook uses the\n\
3740 @code{max-rtl-if-conversion-[un]predictable} parameters if they are set,\n\
3741 and uses a multiple of @code{BRANCH_COST} otherwise.",
3742 unsigned int, (edge e),
3743 default_max_noce_ifcvt_seq_cost)
3745 /* Return true if the given instruction sequence is a good candidate
3746 as a replacement for the if-convertible sequence. */
3747 DEFHOOK
3748 (noce_conversion_profitable_p,
3749 "This hook returns true if the instruction sequence @code{seq} is a good\n\
3750 candidate as a replacement for the if-convertible sequence described in\n\
3751 @code{if_info}.",
3752 bool, (rtx_insn *seq, struct noce_if_info *if_info),
3753 default_noce_conversion_profitable_p)
3755 DEFHOOK
3756 (estimated_poly_value,
3757 "Return an estimate of the runtime value of @var{val}, for use in\n\
3758 things like cost calculations or profiling frequencies. The default\n\
3759 implementation returns the lowest possible value of @var{val}.",
3760 HOST_WIDE_INT, (poly_int64 val),
3761 default_estimated_poly_value)
3763 /* Permit speculative instructions in delay slots during delayed-branch
3764 scheduling. */
3765 DEFHOOK
3766 (no_speculation_in_delay_slots_p,
3767 "This predicate controls the use of the eager delay slot filler to disallow\n\
3768 speculatively executed instructions being placed in delay slots. Targets\n\
3769 such as certain MIPS architectures possess both branches with and without\n\
3770 delay slots. As the eager delay slot filler can decrease performance,\n\
3771 disabling it is beneficial when ordinary branches are available. Use of\n\
3772 delay slot branches filled using the basic filler is often still desirable\n\
3773 as the delay slot can hide a pipeline bubble.", bool, (void),
3774 hook_bool_void_false)
3776 /* Return where to allocate pseudo for a given hard register initial value. */
3777 DEFHOOK
3778 (allocate_initial_value,
3779 "\n\
3780 When the initial value of a hard register has been copied in a pseudo\n\
3781 register, it is often not necessary to actually allocate another register\n\
3782 to this pseudo register, because the original hard register or a stack slot\n\
3783 it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}\n\
3784 is called at the start of register allocation once for each hard register\n\
3785 that had its initial value copied by using\n\
3786 @code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.\n\
3787 Possible values are @code{NULL_RTX}, if you don't want\n\
3788 to do any special allocation, a @code{REG} rtx---that would typically be\n\
3789 the hard register itself, if it is known not to be clobbered---or a\n\
3790 @code{MEM}.\n\
3791 If you are returning a @code{MEM}, this is only a hint for the allocator;\n\
3792 it might decide to use another register anyways.\n\
3793 You may use @code{current_function_is_leaf} or \n\
3794 @code{REG_N_SETS} in the hook to determine if the hard\n\
3795 register in question will not be clobbered.\n\
3796 The default value of this hook is @code{NULL}, which disables any special\n\
3797 allocation.",
3798 rtx, (rtx hard_reg), NULL)
3800 /* Return nonzero if evaluating UNSPEC X might cause a trap.
3801 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
3802 DEFHOOK
3803 (unspec_may_trap_p,
3804 "This target hook returns nonzero if @var{x}, an @code{unspec} or\n\
3805 @code{unspec_volatile} operation, might cause a trap. Targets can use\n\
3806 this hook to enhance precision of analysis for @code{unspec} and\n\
3807 @code{unspec_volatile} operations. You may call @code{may_trap_p_1}\n\
3808 to analyze inner elements of @var{x} in which case @var{flags} should be\n\
3809 passed along.",
3810 int, (const_rtx x, unsigned flags),
3811 default_unspec_may_trap_p)
3813 /* Given a register, this hook should return a parallel of registers
3814 to represent where to find the register pieces. Define this hook
3815 if the register and its mode are represented in Dwarf in
3816 non-contiguous locations, or if the register should be
3817 represented in more than one register in Dwarf. Otherwise, this
3818 hook should return NULL_RTX. */
3819 DEFHOOK
3820 (dwarf_register_span,
3821 "Given a register, this hook should return a parallel of registers to\n\
3822 represent where to find the register pieces. Define this hook if the\n\
3823 register and its mode are represented in Dwarf in non-contiguous\n\
3824 locations, or if the register should be represented in more than one\n\
3825 register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.\n\
3826 If not defined, the default is to return @code{NULL_RTX}.",
3827 rtx, (rtx reg),
3828 hook_rtx_rtx_null)
3830 /* Given a register return the mode of the corresponding DWARF frame
3831 register. */
3832 DEFHOOK
3833 (dwarf_frame_reg_mode,
3834 "Given a register, this hook should return the mode which the\n\
3835 corresponding Dwarf frame register should have. This is normally\n\
3836 used to return a smaller mode than the raw mode to prevent call\n\
3837 clobbered parts of a register altering the frame register size",
3838 machine_mode, (int regno),
3839 default_dwarf_frame_reg_mode)
3841 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
3842 entries not corresponding directly to registers below
3843 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
3844 code, given the address of the table. */
3845 DEFHOOK
3846 (init_dwarf_reg_sizes_extra,
3847 "If some registers are represented in Dwarf-2 unwind information in\n\
3848 multiple pieces, define this hook to fill in information about the\n\
3849 sizes of those pieces in the table used by the unwinder at runtime.\n\
3850 It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after\n\
3851 filling in a single size corresponding to each hard register;\n\
3852 @var{address} is the address of the table.",
3853 void, (tree address),
3854 hook_void_tree)
3856 /* Fetch the fixed register(s) which hold condition codes, for
3857 targets where it makes sense to look for duplicate assignments to
3858 the condition codes. This should return true if there is such a
3859 register, false otherwise. The arguments should be set to the
3860 fixed register numbers. Up to two condition code registers are
3861 supported. If there is only one for this target, the int pointed
3862 at by the second argument should be set to -1. */
3863 DEFHOOK
3864 (fixed_condition_code_regs,
3865 "On targets which do not use @code{(cc0)}, and which use a hard\n\
3866 register rather than a pseudo-register to hold condition codes, the\n\
3867 regular CSE passes are often not able to identify cases in which the\n\
3868 hard register is set to a common value. Use this hook to enable a\n\
3869 small pass which optimizes such cases. This hook should return true\n\
3870 to enable this pass, and it should set the integers to which its\n\
3871 arguments point to the hard register numbers used for condition codes.\n\
3872 When there is only one such register, as is true on most systems, the\n\
3873 integer pointed to by @var{p2} should be set to\n\
3874 @code{INVALID_REGNUM}.\n\
3876 The default version of this hook returns false.",
3877 bool, (unsigned int *p1, unsigned int *p2),
3878 hook_bool_uintp_uintp_false)
3880 /* If two condition code modes are compatible, return a condition
3881 code mode which is compatible with both, such that a comparison
3882 done in the returned mode will work for both of the original
3883 modes. If the condition code modes are not compatible, return
3884 VOIDmode. */
3885 DEFHOOK
3886 (cc_modes_compatible,
3887 "On targets which use multiple condition code modes in class\n\
3888 @code{MODE_CC}, it is sometimes the case that a comparison can be\n\
3889 validly done in more than one mode. On such a system, define this\n\
3890 target hook to take two mode arguments and to return a mode in which\n\
3891 both comparisons may be validly done. If there is no such mode,\n\
3892 return @code{VOIDmode}.\n\
3894 The default version of this hook checks whether the modes are the\n\
3895 same. If they are, it returns that mode. If they are different, it\n\
3896 returns @code{VOIDmode}.",
3897 machine_mode, (machine_mode m1, machine_mode m2),
3898 default_cc_modes_compatible)
3900 /* Do machine-dependent code transformations. Called just before
3901 delayed-branch scheduling. */
3902 DEFHOOK
3903 (machine_dependent_reorg,
3904 "If non-null, this hook performs a target-specific pass over the\n\
3905 instruction stream. The compiler will run it at all optimization levels,\n\
3906 just before the point at which it normally does delayed-branch scheduling.\n\
3908 The exact purpose of the hook varies from target to target. Some use\n\
3909 it to do transformations that are necessary for correctness, such as\n\
3910 laying out in-function constant pools or avoiding hardware hazards.\n\
3911 Others use it as an opportunity to do some machine-dependent optimizations.\n\
3913 You need not implement the hook if it has nothing to do. The default\n\
3914 definition is null.",
3915 void, (void), NULL)
3917 /* Create the __builtin_va_list type. */
3918 DEFHOOK
3919 (build_builtin_va_list,
3920 "This hook returns a type node for @code{va_list} for the target.\n\
3921 The default version of the hook returns @code{void*}.",
3922 tree, (void),
3923 std_build_builtin_va_list)
3925 /* Enumerate the va list variants. */
3926 DEFHOOK
3927 (enum_va_list_p,
3928 "This target hook is used in function @code{c_common_nodes_and_builtins}\n\
3929 to iterate through the target specific builtin types for va_list. The\n\
3930 variable @var{idx} is used as iterator. @var{pname} has to be a pointer\n\
3931 to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed\n\
3932 variable.\n\
3933 The arguments @var{pname} and @var{ptree} are used to store the result of\n\
3934 this macro and are set to the name of the va_list builtin type and its\n\
3935 internal type.\n\
3936 If the return value of this macro is zero, then there is no more element.\n\
3937 Otherwise the @var{IDX} should be increased for the next call of this\n\
3938 macro to iterate through all types.",
3939 int, (int idx, const char **pname, tree *ptree),
3940 NULL)
3942 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
3943 DEFHOOK
3944 (fn_abi_va_list,
3945 "This hook returns the va_list type of the calling convention specified by\n\
3946 @var{fndecl}.\n\
3947 The default version of this hook returns @code{va_list_type_node}.",
3948 tree, (tree fndecl),
3949 std_fn_abi_va_list)
3951 /* Get the __builtin_va_list type dependent on input type. */
3952 DEFHOOK
3953 (canonical_va_list_type,
3954 "This hook returns the va_list type of the calling convention specified by the\n\
3955 type of @var{type}. If @var{type} is not a valid va_list type, it returns\n\
3956 @code{NULL_TREE}.",
3957 tree, (tree type),
3958 std_canonical_va_list_type)
3960 /* ??? Documenting this hook requires a GFDL license grant. */
3961 DEFHOOK_UNDOC
3962 (expand_builtin_va_start,
3963 "Expand the @code{__builtin_va_start} builtin.",
3964 void, (tree valist, rtx nextarg), NULL)
3966 /* Gimplifies a VA_ARG_EXPR. */
3967 DEFHOOK
3968 (gimplify_va_arg_expr,
3969 "This hook performs target-specific gimplification of\n\
3970 @code{VA_ARG_EXPR}. The first two parameters correspond to the\n\
3971 arguments to @code{va_arg}; the latter two are as in\n\
3972 @code{gimplify.c:gimplify_expr}.",
3973 tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
3974 std_gimplify_va_arg_expr)
3976 /* Validity-checking routines for PCH files, target-specific.
3977 get_pch_validity returns a pointer to the data to be stored,
3978 and stores the size in its argument. pch_valid_p gets the same
3979 information back and returns NULL if the PCH is valid,
3980 or an error message if not. */
3981 DEFHOOK
3982 (get_pch_validity,
3983 "This hook returns a pointer to the data needed by\n\
3984 @code{TARGET_PCH_VALID_P} and sets\n\
3985 @samp{*@var{sz}} to the size of the data in bytes.",
3986 void *, (size_t *sz),
3987 default_get_pch_validity)
3989 DEFHOOK
3990 (pch_valid_p,
3991 "This hook checks whether the options used to create a PCH file are\n\
3992 compatible with the current settings. It returns @code{NULL}\n\
3993 if so and a suitable error message if not. Error messages will\n\
3994 be presented to the user and must be localized using @samp{_(@var{msg})}.\n\
3996 @var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}\n\
3997 when the PCH file was created and @var{sz} is the size of that data in bytes.\n\
3998 It's safe to assume that the data was created by the same version of the\n\
3999 compiler, so no format checking is needed.\n\
4001 The default definition of @code{default_pch_valid_p} should be\n\
4002 suitable for most targets.",
4003 const char *, (const void *data, size_t sz),
4004 default_pch_valid_p)
4006 DEFHOOK
4007 (prepare_pch_save,
4008 "Called before writing out a PCH file. If the target has some\n\
4009 garbage-collected data that needs to be in a particular state on PCH loads,\n\
4010 it can use this hook to enforce that state. Very few targets need\n\
4011 to do anything here.",
4012 void, (void),
4013 hook_void_void)
4015 /* If nonnull, this function checks whether a PCH file with the
4016 given set of target flags can be used. It returns NULL if so,
4017 otherwise it returns an error message. */
4018 DEFHOOK
4019 (check_pch_target_flags,
4020 "If this hook is nonnull, the default implementation of\n\
4021 @code{TARGET_PCH_VALID_P} will use it to check for compatible values\n\
4022 of @code{target_flags}. @var{pch_flags} specifies the value that\n\
4023 @code{target_flags} had when the PCH file was created. The return\n\
4024 value is the same as for @code{TARGET_PCH_VALID_P}.",
4025 const char *, (int pch_flags), NULL)
4027 /* True if the compiler should give an enum type only as many
4028 bytes as it takes to represent the range of possible values of
4029 that type. */
4030 DEFHOOK
4031 (default_short_enums,
4032 "This target hook should return true if the compiler should give an\n\
4033 @code{enum} type only as many bytes as it takes to represent the range\n\
4034 of possible values of that type. It should return false if all\n\
4035 @code{enum} types should be allocated like @code{int}.\n\
4037 The default is to return false.",
4038 bool, (void),
4039 hook_bool_void_false)
4041 /* This target hook returns an rtx that is used to store the address
4042 of the current frame into the built-in setjmp buffer. */
4043 DEFHOOK
4044 (builtin_setjmp_frame_value,
4045 "This target hook should return an rtx that is used to store\n\
4046 the address of the current frame into the built in @code{setjmp} buffer.\n\
4047 The default value, @code{virtual_stack_vars_rtx}, is correct for most\n\
4048 machines. One reason you may need to define this target hook is if\n\
4049 @code{hard_frame_pointer_rtx} is the appropriate value on your machine.",
4050 rtx, (void),
4051 default_builtin_setjmp_frame_value)
4053 /* This target hook should manipulate the outputs, inputs, constraints,
4054 and clobbers the port wishes for pre-processing the asm. */
4055 DEFHOOK
4056 (md_asm_adjust,
4057 "This target hook may add @dfn{clobbers} to @var{clobbers} and\n\
4058 @var{clobbered_regs} for any hard regs the port wishes to automatically\n\
4059 clobber for an asm. The @var{outputs} and @var{inputs} may be inspected\n\
4060 to avoid clobbering a register that is already used by the asm.\n\
4062 It may modify the @var{outputs}, @var{inputs}, and @var{constraints}\n\
4063 as necessary for other pre-processing. In this case the return value is\n\
4064 a sequence of insns to emit after the asm.",
4065 rtx_insn *,
4066 (vec<rtx>& outputs, vec<rtx>& inputs, vec<const char *>& constraints,
4067 vec<rtx>& clobbers, HARD_REG_SET& clobbered_regs),
4068 NULL)
4070 /* This target hook allows the backend to specify a calling convention
4071 in the debug information. This function actually returns an
4072 enum dwarf_calling_convention, but because of forward declarations
4073 and not wanting to include dwarf2.h everywhere target.h is included
4074 the function is being declared as an int. */
4075 DEFHOOK
4076 (dwarf_calling_convention,
4077 "Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to\n\
4078 be emitted for each function. Instead of an integer return the enum\n\
4079 value for the @code{DW_CC_} tag.",
4080 int, (const_tree function),
4081 hook_int_const_tree_0)
4083 /* This target hook allows the backend to emit frame-related insns that
4084 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
4085 engine will invoke it on insns of the form
4086 (set (reg) (unspec [...] UNSPEC_INDEX))
4088 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
4089 to let the backend emit the call frame instructions. */
4090 DEFHOOK
4091 (dwarf_handle_frame_unspec,
4092 "This target hook allows the backend to emit frame-related insns that\n\
4093 contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging\n\
4094 info engine will invoke it on insns of the form\n\
4095 @smallexample\n\
4096 (set (reg) (unspec [@dots{}] UNSPEC_INDEX))\n\
4097 @end smallexample\n\
4098 and\n\
4099 @smallexample\n\
4100 (set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).\n\
4101 @end smallexample\n\
4102 to let the backend emit the call frame instructions. @var{label} is\n\
4103 the CFI label attached to the insn, @var{pattern} is the pattern of\n\
4104 the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.",
4105 void, (const char *label, rtx pattern, int index), NULL)
4107 DEFHOOK
4108 (dwarf_poly_indeterminate_value,
4109 "Express the value of @code{poly_int} indeterminate @var{i} as a DWARF\n\
4110 expression, with @var{i} counting from 1. Return the number of a DWARF\n\
4111 register @var{R} and set @samp{*@var{factor}} and @samp{*@var{offset}} such\n\
4112 that the value of the indeterminate is:\n\
4113 @smallexample\n\
4114 value_of(@var{R}) / @var{factor} - @var{offset}\n\
4115 @end smallexample\n\
4117 A target only needs to define this hook if it sets\n\
4118 @samp{NUM_POLY_INT_COEFFS} to a value greater than 1.",
4119 unsigned int, (unsigned int i, unsigned int *factor, int *offset),
4120 default_dwarf_poly_indeterminate_value)
4122 /* ??? Documenting this hook requires a GFDL license grant. */
4123 DEFHOOK_UNDOC
4124 (stdarg_optimize_hook,
4125 "Perform architecture specific checking of statements gimplified\
4126 from @code{VA_ARG_EXPR}. @var{stmt} is the statement. Returns true if\
4127 the statement doesn't need to be checked for @code{va_list} references.",
4128 bool, (struct stdarg_info *ai, const gimple *stmt), NULL)
4130 /* This target hook allows the operating system to override the DECL
4131 that represents the external variable that contains the stack
4132 protection guard variable. The type of this DECL is ptr_type_node. */
4133 DEFHOOK
4134 (stack_protect_guard,
4135 "This hook returns a @code{DECL} node for the external variable to use\n\
4136 for the stack protection guard. This variable is initialized by the\n\
4137 runtime to some random value and is used to initialize the guard value\n\
4138 that is placed at the top of the local stack frame. The type of this\n\
4139 variable must be @code{ptr_type_node}.\n\
4141 The default version of this hook creates a variable called\n\
4142 @samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.",
4143 tree, (void),
4144 default_stack_protect_guard)
4146 /* This target hook allows the operating system to override the CALL_EXPR
4147 that is invoked when a check vs the guard variable fails. */
4148 DEFHOOK
4149 (stack_protect_fail,
4150 "This hook returns a @code{CALL_EXPR} that alerts the runtime that the\n\
4151 stack protect guard variable has been modified. This expression should\n\
4152 involve a call to a @code{noreturn} function.\n\
4154 The default version of this hook invokes a function called\n\
4155 @samp{__stack_chk_fail}, taking no arguments. This function is\n\
4156 normally defined in @file{libgcc2.c}.",
4157 tree, (void),
4158 default_external_stack_protect_fail)
4160 /* This target hook allows the operating system to disable the default stack
4161 protector runtime support. */
4162 DEFHOOK
4163 (stack_protect_runtime_enabled_p,
4164 "Returns true if the target wants GCC's default stack protect runtime support,\
4165 otherwise return false. The default implementation always returns true.",
4166 bool, (void),
4167 hook_bool_void_true)
4169 DEFHOOK
4170 (can_use_doloop_p,
4171 "Return true if it is possible to use low-overhead loops (@code{doloop_end}\n\
4172 and @code{doloop_begin}) for a particular loop. @var{iterations} gives the\n\
4173 exact number of iterations, or 0 if not known. @var{iterations_max} gives\n\
4174 the maximum number of iterations, or 0 if not known. @var{loop_depth} is\n\
4175 the nesting depth of the loop, with 1 for innermost loops, 2 for loops that\n\
4176 contain innermost loops, and so on. @var{entered_at_top} is true if the\n\
4177 loop is only entered from the top.\n\
4179 This hook is only used if @code{doloop_end} is available. The default\n\
4180 implementation returns true. You can use @code{can_use_doloop_if_innermost}\n\
4181 if the loop must be the innermost, and if there are no other restrictions.",
4182 bool, (const widest_int &iterations, const widest_int &iterations_max,
4183 unsigned int loop_depth, bool entered_at_top),
4184 hook_bool_wint_wint_uint_bool_true)
4186 /* Returns NULL if target supports the insn within a doloop block,
4187 otherwise it returns an error message. */
4188 DEFHOOK
4189 (invalid_within_doloop,
4190 "\n\
4191 Take an instruction in @var{insn} and return NULL if it is valid within a\n\
4192 low-overhead loop, otherwise return a string explaining why doloop\n\
4193 could not be applied.\n\
4195 Many targets use special registers for low-overhead looping. For any\n\
4196 instruction that clobbers these this function should return a string indicating\n\
4197 the reason why the doloop could not be applied.\n\
4198 By default, the RTL loop optimizer does not use a present doloop pattern for\n\
4199 loops containing function calls or branch on table instructions.",
4200 const char *, (const rtx_insn *insn),
4201 default_invalid_within_doloop)
4203 /* Returns true for a legitimate combined insn. */
4204 DEFHOOK
4205 (legitimate_combined_insn,
4206 "Take an instruction in @var{insn} and return @code{false} if the instruction\
4207 is not appropriate as a combination of two or more instructions. The\
4208 default is to accept all instructions.",
4209 bool, (rtx_insn *insn),
4210 hook_bool_rtx_insn_true)
4212 DEFHOOK
4213 (valid_dllimport_attribute_p,
4214 "@var{decl} is a variable or function with @code{__attribute__((dllimport))}\
4215 specified. Use this hook if the target needs to add extra validation\
4216 checks to @code{handle_dll_attribute}.",
4217 bool, (const_tree decl),
4218 hook_bool_const_tree_true)
4220 /* If non-zero, align constant anchors in CSE to a multiple of this
4221 value. */
4222 DEFHOOKPOD
4223 (const_anchor,
4224 "On some architectures it can take multiple instructions to synthesize\n\
4225 a constant. If there is another constant already in a register that\n\
4226 is close enough in value then it is preferable that the new constant\n\
4227 is computed from this register using immediate addition or\n\
4228 subtraction. We accomplish this through CSE. Besides the value of\n\
4229 the constant we also add a lower and an upper constant anchor to the\n\
4230 available expressions. These are then queried when encountering new\n\
4231 constants. The anchors are computed by rounding the constant up and\n\
4232 down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.\n\
4233 @code{TARGET_CONST_ANCHOR} should be the maximum positive value\n\
4234 accepted by immediate-add plus one. We currently assume that the\n\
4235 value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on\n\
4236 MIPS, where add-immediate takes a 16-bit signed value,\n\
4237 @code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value\n\
4238 is zero, which disables this optimization.",
4239 unsigned HOST_WIDE_INT, 0)
4241 /* Defines, which target-dependent bits (upper 16) are used by port */
4242 DEFHOOK
4243 (memmodel_check,
4244 "Validate target specific memory model mask bits. When NULL no target specific\n\
4245 memory model bits are allowed.",
4246 unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)
4248 /* Defines an offset bitwise ored into shifted address to get corresponding
4249 Address Sanitizer shadow address, or -1 if Address Sanitizer is not
4250 supported by the target. */
4251 DEFHOOK
4252 (asan_shadow_offset,
4253 "Return the offset bitwise ored into shifted address to get corresponding\n\
4254 Address Sanitizer shadow memory address. NULL if Address Sanitizer is not\n\
4255 supported by the target.",
4256 unsigned HOST_WIDE_INT, (void),
4257 NULL)
4259 /* Functions relating to calls - argument passing, returns, etc. */
4260 /* Members of struct call have no special macro prefix. */
4261 HOOK_VECTOR (TARGET_CALLS, calls)
4263 DEFHOOK
4264 (promote_function_mode,
4265 "Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or\n\
4266 function return values. The target hook should return the new mode\n\
4267 and possibly change @code{*@var{punsignedp}} if the promotion should\n\
4268 change signedness. This function is called only for scalar @emph{or\n\
4269 pointer} types.\n\
4271 @var{for_return} allows to distinguish the promotion of arguments and\n\
4272 return values. If it is @code{1}, a return value is being promoted and\n\
4273 @code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.\n\
4274 If it is @code{2}, the returned mode should be that of the register in\n\
4275 which an incoming parameter is copied, or the outgoing result is computed;\n\
4276 then the hook should return the same mode as @code{promote_mode}, though\n\
4277 the signedness may be different.\n\
4279 @var{type} can be NULL when promoting function arguments of libcalls.\n\
4281 The default is to not promote arguments and return values. You can\n\
4282 also define the hook to @code{default_promote_function_mode_always_promote}\n\
4283 if you would like to apply the same rules given by @code{PROMOTE_MODE}.",
4284 machine_mode, (const_tree type, machine_mode mode, int *punsignedp,
4285 const_tree funtype, int for_return),
4286 default_promote_function_mode)
4288 DEFHOOK
4289 (promote_prototypes,
4290 "This target hook returns @code{true} if an argument declared in a\n\
4291 prototype as an integral type smaller than @code{int} should actually be\n\
4292 passed as an @code{int}. In addition to avoiding errors in certain\n\
4293 cases of mismatch, it also makes for better code on certain machines.\n\
4294 The default is to not promote prototypes.",
4295 bool, (const_tree fntype),
4296 hook_bool_const_tree_false)
4298 DEFHOOK
4299 (struct_value_rtx,
4300 "This target hook should return the location of the structure value\n\
4301 address (normally a @code{mem} or @code{reg}), or 0 if the address is\n\
4302 passed as an ``invisible'' first argument. Note that @var{fndecl} may\n\
4303 be @code{NULL}, for libcalls. You do not need to define this target\n\
4304 hook if the address is always passed as an ``invisible'' first\n\
4305 argument.\n\
4307 On some architectures the place where the structure value address\n\
4308 is found by the called function is not the same place that the\n\
4309 caller put it. This can be due to register windows, or it could\n\
4310 be because the function prologue moves it to a different place.\n\
4311 @var{incoming} is @code{1} or @code{2} when the location is needed in\n\
4312 the context of the called function, and @code{0} in the context of\n\
4313 the caller.\n\
4315 If @var{incoming} is nonzero and the address is to be found on the\n\
4316 stack, return a @code{mem} which refers to the frame pointer. If\n\
4317 @var{incoming} is @code{2}, the result is being used to fetch the\n\
4318 structure value address at the beginning of a function. If you need\n\
4319 to emit adjusting code, you should do it at this point.",
4320 rtx, (tree fndecl, int incoming),
4321 hook_rtx_tree_int_null)
4323 DEFHOOKPOD
4324 (omit_struct_return_reg,
4325 "Normally, when a function returns a structure by memory, the address\n\
4326 is passed as an invisible pointer argument, but the compiler also\n\
4327 arranges to return the address from the function like it would a normal\n\
4328 pointer return value. Define this to true if that behavior is\n\
4329 undesirable on your target.",
4330 bool, false)
4332 DEFHOOK
4333 (return_in_memory,
4334 "This target hook should return a nonzero value to say to return the\n\
4335 function value in memory, just as large structures are always returned.\n\
4336 Here @var{type} will be the data type of the value, and @var{fntype}\n\
4337 will be the type of the function doing the returning, or @code{NULL} for\n\
4338 libcalls.\n\
4340 Note that values of mode @code{BLKmode} must be explicitly handled\n\
4341 by this function. Also, the option @option{-fpcc-struct-return}\n\
4342 takes effect regardless of this macro. On most systems, it is\n\
4343 possible to leave the hook undefined; this causes a default\n\
4344 definition to be used, whose value is the constant 1 for @code{BLKmode}\n\
4345 values, and 0 otherwise.\n\
4347 Do not use this hook to indicate that structures and unions should always\n\
4348 be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}\n\
4349 to indicate this.",
4350 bool, (const_tree type, const_tree fntype),
4351 default_return_in_memory)
4353 DEFHOOK
4354 (return_in_msb,
4355 "This hook should return true if values of type @var{type} are returned\n\
4356 at the most significant end of a register (in other words, if they are\n\
4357 padded at the least significant end). You can assume that @var{type}\n\
4358 is returned in a register; the caller is required to check this.\n\
4360 Note that the register provided by @code{TARGET_FUNCTION_VALUE} must\n\
4361 be able to hold the complete return value. For example, if a 1-, 2-\n\
4362 or 3-byte structure is returned at the most significant end of a\n\
4363 4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an\n\
4364 @code{SImode} rtx.",
4365 bool, (const_tree type),
4366 hook_bool_const_tree_false)
4368 /* Return true if a parameter must be passed by reference. TYPE may
4369 be null if this is a libcall. CA may be null if this query is
4370 from __builtin_va_arg. */
4371 DEFHOOK
4372 (pass_by_reference,
4373 "This target hook should return @code{true} if an argument at the\n\
4374 position indicated by @var{cum} should be passed by reference. This\n\
4375 predicate is queried after target independent reasons for being\n\
4376 passed by reference, such as @code{TREE_ADDRESSABLE (type)}.\n\
4378 If the hook returns true, a copy of that argument is made in memory and a\n\
4379 pointer to the argument is passed instead of the argument itself.\n\
4380 The pointer is passed in whatever way is appropriate for passing a pointer\n\
4381 to that type.",
4382 bool,
4383 (cumulative_args_t cum, machine_mode mode, const_tree type, bool named),
4384 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
4386 DEFHOOK
4387 (expand_builtin_saveregs,
4388 "If defined, this hook produces the machine-specific code for a call to\n\
4389 @code{__builtin_saveregs}. This code will be moved to the very\n\
4390 beginning of the function, before any parameter access are made. The\n\
4391 return value of this function should be an RTX that contains the value\n\
4392 to use as the return of @code{__builtin_saveregs}.",
4393 rtx, (void),
4394 default_expand_builtin_saveregs)
4396 /* Returns pretend_argument_size. */
4397 DEFHOOK
4398 (setup_incoming_varargs,
4399 "This target hook offers an alternative to using\n\
4400 @code{__builtin_saveregs} and defining the hook\n\
4401 @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous\n\
4402 register arguments into the stack so that all the arguments appear to\n\
4403 have been passed consecutively on the stack. Once this is done, you can\n\
4404 use the standard implementation of varargs that works for machines that\n\
4405 pass all their arguments on the stack.\n\
4407 The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data\n\
4408 structure, containing the values that are obtained after processing the\n\
4409 named arguments. The arguments @var{mode} and @var{type} describe the\n\
4410 last named argument---its machine mode and its data type as a tree node.\n\
4412 The target hook should do two things: first, push onto the stack all the\n\
4413 argument registers @emph{not} used for the named arguments, and second,\n\
4414 store the size of the data thus pushed into the @code{int}-valued\n\
4415 variable pointed to by @var{pretend_args_size}. The value that you\n\
4416 store here will serve as additional offset for setting up the stack\n\
4417 frame.\n\
4419 Because you must generate code to push the anonymous arguments at\n\
4420 compile time without knowing their data types,\n\
4421 @code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that\n\
4422 have just a single category of argument register and use it uniformly\n\
4423 for all data types.\n\
4425 If the argument @var{second_time} is nonzero, it means that the\n\
4426 arguments of the function are being analyzed for the second time. This\n\
4427 happens for an inline function, which is not actually compiled until the\n\
4428 end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should\n\
4429 not generate any instructions in this case.",
4430 void, (cumulative_args_t args_so_far, machine_mode mode, tree type,
4431 int *pretend_args_size, int second_time),
4432 default_setup_incoming_varargs)
4434 DEFHOOK
4435 (load_bounds_for_arg,
4436 "This hook is used by expand pass to emit insn to load bounds of\n\
4437 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4438 bounds of @var{arg} are not passed in register. If @var{slot} is a\n\
4439 memory, then bounds are loaded as for regular pointer loaded from\n\
4440 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4441 constant holding number of the target dependent special slot which\n\
4442 should be used to obtain bounds. Hook returns RTX holding loaded bounds.",
4443 rtx, (rtx slot, rtx arg, rtx slot_no),
4444 default_load_bounds_for_arg)
4446 DEFHOOK
4447 (store_bounds_for_arg,
4448 "This hook is used by expand pass to emit insns to store @var{bounds} of\n\
4449 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4450 @var{bounds} of @var{arg} are not passed in register. If @var{slot} is a\n\
4451 memory, then @var{bounds} are stored as for regular pointer stored in\n\
4452 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4453 constant holding number of the target dependent special slot which\n\
4454 should be used to store @var{bounds}.",
4455 void, (rtx arg, rtx slot, rtx bounds, rtx slot_no),
4456 default_store_bounds_for_arg)
4458 DEFHOOK
4459 (load_returned_bounds,
4460 "This hook is used by expand pass to emit insn to load bounds\n\
4461 returned by function call in @var{slot}. Hook returns RTX holding\n\
4462 loaded bounds.",
4463 rtx, (rtx slot),
4464 default_load_returned_bounds)
4466 DEFHOOK
4467 (store_returned_bounds,
4468 "This hook is used by expand pass to emit insn to store @var{bounds}\n\
4469 returned by function call into @var{slot}.",
4470 void, (rtx slot, rtx bounds),
4471 default_store_returned_bounds)
4473 DEFHOOK
4474 (setup_incoming_vararg_bounds,
4475 "Use it to store bounds for anonymous register arguments stored\n\
4476 into the stack. Arguments meaning is similar to\n\
4477 @code{TARGET_SETUP_INCOMING_VARARGS}.",
4478 void, (cumulative_args_t args_so_far, machine_mode mode, tree type,
4479 int *pretend_args_size, int second_time),
4480 default_setup_incoming_vararg_bounds)
4482 DEFHOOK
4483 (call_args,
4484 "While generating RTL for a function call, this target hook is invoked once\n\
4485 for each argument passed to the function, either a register returned by\n\
4486 @code{TARGET_FUNCTION_ARG} or a memory location. It is called just\n\
4487 before the point where argument registers are stored. The type of the\n\
4488 function to be called is also passed as the second argument; it is\n\
4489 @code{NULL_TREE} for libcalls. The @code{TARGET_END_CALL_ARGS} hook is\n\
4490 invoked just after the code to copy the return reg has been emitted.\n\
4491 This functionality can be used to perform special setup of call argument\n\
4492 registers if a target needs it.\n\
4493 For functions without arguments, the hook is called once with @code{pc_rtx}\n\
4494 passed instead of an argument register.\n\
4495 Most ports do not need to implement anything for this hook.",
4496 void, (rtx, tree),
4497 hook_void_rtx_tree)
4499 DEFHOOK
4500 (end_call_args,
4501 "This target hook is invoked while generating RTL for a function call,\n\
4502 just after the point where the return reg is copied into a pseudo. It\n\
4503 signals that all the call argument and return registers for the just\n\
4504 emitted call are now no longer in use.\n\
4505 Most ports do not need to implement anything for this hook.",
4506 void, (void),
4507 hook_void_void)
4509 DEFHOOK
4510 (strict_argument_naming,
4511 "Define this hook to return @code{true} if the location where a function\n\
4512 argument is passed depends on whether or not it is a named argument.\n\
4514 This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}\n\
4515 is set for varargs and stdarg functions. If this hook returns\n\
4516 @code{true}, the @var{named} argument is always true for named\n\
4517 arguments, and false for unnamed arguments. If it returns @code{false},\n\
4518 but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},\n\
4519 then all arguments are treated as named. Otherwise, all named arguments\n\
4520 except the last are treated as named.\n\
4522 You need not define this hook if it always returns @code{false}.",
4523 bool, (cumulative_args_t ca),
4524 hook_bool_CUMULATIVE_ARGS_false)
4526 /* Returns true if we should use
4527 targetm.calls.setup_incoming_varargs() and/or
4528 targetm.calls.strict_argument_naming(). */
4529 DEFHOOK
4530 (pretend_outgoing_varargs_named,
4531 "If you need to conditionally change ABIs so that one works with\n\
4532 @code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither\n\
4533 @code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was\n\
4534 defined, then define this hook to return @code{true} if\n\
4535 @code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.\n\
4536 Otherwise, you should not define this hook.",
4537 bool, (cumulative_args_t ca),
4538 default_pretend_outgoing_varargs_named)
4540 /* Given a complex type T, return true if a parameter of type T
4541 should be passed as two scalars. */
4542 DEFHOOK
4543 (split_complex_arg,
4544 "This hook should return true if parameter of type @var{type} are passed\n\
4545 as two scalar parameters. By default, GCC will attempt to pack complex\n\
4546 arguments into the target's word size. Some ABIs require complex arguments\n\
4547 to be split and treated as their individual components. For example, on\n\
4548 AIX64, complex floats should be passed in a pair of floating point\n\
4549 registers, even though a complex float would fit in one 64-bit floating\n\
4550 point register.\n\
4552 The default value of this hook is @code{NULL}, which is treated as always\n\
4553 false.",
4554 bool, (const_tree type), NULL)
4556 /* Return true if type T, mode MODE, may not be passed in registers,
4557 but must be passed on the stack. */
4558 /* ??? This predicate should be applied strictly after pass-by-reference.
4559 Need audit to verify that this is the case. */
4560 DEFHOOK
4561 (must_pass_in_stack,
4562 "This target hook should return @code{true} if we should not pass @var{type}\n\
4563 solely in registers. The file @file{expr.h} defines a\n\
4564 definition that is usually appropriate, refer to @file{expr.h} for additional\n\
4565 documentation.",
4566 bool, (machine_mode mode, const_tree type),
4567 must_pass_in_stack_var_size_or_pad)
4569 /* Return true if type TYPE, mode MODE, which is passed by reference,
4570 should have the object copy generated by the callee rather than
4571 the caller. It is never called for TYPE requiring constructors. */
4572 DEFHOOK
4573 (callee_copies,
4574 "The function argument described by the parameters to this hook is\n\
4575 known to be passed by reference. The hook should return true if the\n\
4576 function argument should be copied by the callee instead of copied\n\
4577 by the caller.\n\
4579 For any argument for which the hook returns true, if it can be\n\
4580 determined that the argument is not modified, then a copy need\n\
4581 not be generated.\n\
4583 The default version of this hook always returns false.",
4584 bool,
4585 (cumulative_args_t cum, machine_mode mode, const_tree type, bool named),
4586 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
4588 /* Return zero for arguments passed entirely on the stack or entirely
4589 in registers. If passed in both, return the number of bytes passed
4590 in registers; the balance is therefore passed on the stack. */
4591 DEFHOOK
4592 (arg_partial_bytes,
4593 "This target hook returns the number of bytes at the beginning of an\n\
4594 argument that must be put in registers. The value must be zero for\n\
4595 arguments that are passed entirely in registers or that are entirely\n\
4596 pushed on the stack.\n\
4598 On some machines, certain arguments must be passed partially in\n\
4599 registers and partially in memory. On these machines, typically the\n\
4600 first few words of arguments are passed in registers, and the rest\n\
4601 on the stack. If a multi-word argument (a @code{double} or a\n\
4602 structure) crosses that boundary, its first few words must be passed\n\
4603 in registers and the rest must be pushed. This macro tells the\n\
4604 compiler when this occurs, and how many bytes should go in registers.\n\
4606 @code{TARGET_FUNCTION_ARG} for these arguments should return the first\n\
4607 register to be used by the caller for this argument; likewise\n\
4608 @code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.",
4609 int, (cumulative_args_t cum, machine_mode mode, tree type, bool named),
4610 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0)
4612 /* Update the state in CA to advance past an argument in the
4613 argument list. The values MODE, TYPE, and NAMED describe that
4614 argument. */
4615 DEFHOOK
4616 (function_arg_advance,
4617 "This hook updates the summarizer variable pointed to by @var{ca} to\n\
4618 advance past an argument in the argument list. The values @var{mode},\n\
4619 @var{type} and @var{named} describe that argument. Once this is done,\n\
4620 the variable @var{cum} is suitable for analyzing the @emph{following}\n\
4621 argument with @code{TARGET_FUNCTION_ARG}, etc.\n\
4623 This hook need not do anything if the argument in question was passed\n\
4624 on the stack. The compiler knows how to track the amount of stack space\n\
4625 used for arguments without any special help.",
4626 void,
4627 (cumulative_args_t ca, machine_mode mode, const_tree type, bool named),
4628 default_function_arg_advance)
4630 DEFHOOK
4631 (function_arg_offset,
4632 "This hook returns the number of bytes to add to the offset of an\n\
4633 argument of type @var{type} and mode @var{mode} when passed in memory.\n\
4634 This is needed for the SPU, which passes @code{char} and @code{short}\n\
4635 arguments in the preferred slot that is in the middle of the quad word\n\
4636 instead of starting at the top. The default implementation returns 0.",
4637 HOST_WIDE_INT, (machine_mode mode, const_tree type),
4638 default_function_arg_offset)
4640 DEFHOOK
4641 (function_arg_padding,
4642 "This hook determines whether, and in which direction, to pad out\n\
4643 an argument of mode @var{mode} and type @var{type}. It returns\n\
4644 @code{PAD_UPWARD} to insert padding above the argument, @code{PAD_DOWNWARD}\n\
4645 to insert padding below the argument, or @code{PAD_NONE} to inhibit padding.\n\
4647 The @emph{amount} of padding is not controlled by this hook, but by\n\
4648 @code{TARGET_FUNCTION_ARG_ROUND_BOUNDARY}. It is always just enough\n\
4649 to reach the next multiple of that boundary.\n\
4651 This hook has a default definition that is right for most systems.\n\
4652 For little-endian machines, the default is to pad upward. For\n\
4653 big-endian machines, the default is to pad downward for an argument of\n\
4654 constant size shorter than an @code{int}, and upward otherwise.",
4655 pad_direction, (machine_mode mode, const_tree type),
4656 default_function_arg_padding)
4658 /* Return zero if the argument described by the state of CA should
4659 be placed on a stack, or a hard register in which to store the
4660 argument. The values MODE, TYPE, and NAMED describe that
4661 argument. */
4662 DEFHOOK
4663 (function_arg,
4664 "Return an RTX indicating whether a function argument is passed in a\n\
4665 register and if so, which register.\n\
4667 The arguments are @var{ca}, which summarizes all the previous\n\
4668 arguments; @var{mode}, the machine mode of the argument; @var{type},\n\
4669 the data type of the argument as a tree node or 0 if that is not known\n\
4670 (which happens for C support library functions); and @var{named},\n\
4671 which is @code{true} for an ordinary argument and @code{false} for\n\
4672 nameless arguments that correspond to @samp{@dots{}} in the called\n\
4673 function's prototype. @var{type} can be an incomplete type if a\n\
4674 syntax error has previously occurred.\n\
4676 The return value is usually either a @code{reg} RTX for the hard\n\
4677 register in which to pass the argument, or zero to pass the argument\n\
4678 on the stack.\n\
4680 The return value can be a @code{const_int} which means argument is\n\
4681 passed in a target specific slot with specified number. Target hooks\n\
4682 should be used to store or load argument in such case. See\n\
4683 @code{TARGET_STORE_BOUNDS_FOR_ARG} and @code{TARGET_LOAD_BOUNDS_FOR_ARG}\n\
4684 for more information.\n\
4686 The value of the expression can also be a @code{parallel} RTX@. This is\n\
4687 used when an argument is passed in multiple locations. The mode of the\n\
4688 @code{parallel} should be the mode of the entire argument. The\n\
4689 @code{parallel} holds any number of @code{expr_list} pairs; each one\n\
4690 describes where part of the argument is passed. In each\n\
4691 @code{expr_list} the first operand must be a @code{reg} RTX for the hard\n\
4692 register in which to pass this part of the argument, and the mode of the\n\
4693 register RTX indicates how large this part of the argument is. The\n\
4694 second operand of the @code{expr_list} is a @code{const_int} which gives\n\
4695 the offset in bytes into the entire argument of where this part starts.\n\
4696 As a special exception the first @code{expr_list} in the @code{parallel}\n\
4697 RTX may have a first operand of zero. This indicates that the entire\n\
4698 argument is also stored on the stack.\n\
4700 The last time this hook is called, it is called with @code{MODE ==\n\
4701 VOIDmode}, and its result is passed to the @code{call} or @code{call_value}\n\
4702 pattern as operands 2 and 3 respectively.\n\
4704 @cindex @file{stdarg.h} and register arguments\n\
4705 The usual way to make the ISO library @file{stdarg.h} work on a\n\
4706 machine where some arguments are usually passed in registers, is to\n\
4707 cause nameless arguments to be passed on the stack instead. This is\n\
4708 done by making @code{TARGET_FUNCTION_ARG} return 0 whenever\n\
4709 @var{named} is @code{false}.\n\
4711 @cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}\n\
4712 @cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}\n\
4713 You may use the hook @code{targetm.calls.must_pass_in_stack}\n\
4714 in the definition of this macro to determine if this argument is of a\n\
4715 type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}\n\
4716 is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an\n\
4717 argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is\n\
4718 defined, the argument will be computed in the stack and then loaded into\n\
4719 a register.",
4720 rtx, (cumulative_args_t ca, machine_mode mode, const_tree type,
4721 bool named),
4722 default_function_arg)
4724 DEFHOOK
4725 (function_incoming_arg,
4726 "Define this hook if the caller and callee on the target have different\n\
4727 views of where arguments are passed. Also define this hook if there are\n\
4728 functions that are never directly called, but are invoked by the hardware\n\
4729 and which have nonstandard calling conventions.\n\
4731 In this case @code{TARGET_FUNCTION_ARG} computes the register in\n\
4732 which the caller passes the value, and\n\
4733 @code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar\n\
4734 fashion to tell the function being called where the arguments will\n\
4735 arrive.\n\
4737 @code{TARGET_FUNCTION_INCOMING_ARG} can also return arbitrary address\n\
4738 computation using hard register, which can be forced into a register,\n\
4739 so that it can be used to pass special arguments.\n\
4741 If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,\n\
4742 @code{TARGET_FUNCTION_ARG} serves both purposes.",
4743 rtx, (cumulative_args_t ca, machine_mode mode, const_tree type,
4744 bool named),
4745 default_function_incoming_arg)
4747 DEFHOOK
4748 (function_arg_boundary,
4749 "This hook returns the alignment boundary, in bits, of an argument\n\
4750 with the specified mode and type. The default hook returns\n\
4751 @code{PARM_BOUNDARY} for all arguments.",
4752 unsigned int, (machine_mode mode, const_tree type),
4753 default_function_arg_boundary)
4755 DEFHOOK
4756 (function_arg_round_boundary,
4757 "Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
4758 which is the default value for this hook. You can define this hook to\n\
4759 return a different value if an argument size must be rounded to a larger\n\
4760 value.",
4761 unsigned int, (machine_mode mode, const_tree type),
4762 default_function_arg_round_boundary)
4764 /* Return the diagnostic message string if function without a prototype
4765 is not allowed for this 'val' argument; NULL otherwise. */
4766 DEFHOOK
4767 (invalid_arg_for_unprototyped_fn,
4768 "If defined, this macro returns the diagnostic message when it is\n\
4769 illegal to pass argument @var{val} to function @var{funcdecl}\n\
4770 with prototype @var{typelist}.",
4771 const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
4772 hook_invalid_arg_for_unprototyped_fn)
4774 /* Return an rtx for the return value location of the function
4775 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
4776 DEFHOOK
4777 (function_value,
4778 "\n\
4779 Define this to return an RTX representing the place where a function\n\
4780 returns or receives a value of data type @var{ret_type}, a tree node\n\
4781 representing a data type. @var{fn_decl_or_type} is a tree node\n\
4782 representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a\n\
4783 function being called. If @var{outgoing} is false, the hook should\n\
4784 compute the register in which the caller will see the return value.\n\
4785 Otherwise, the hook should return an RTX representing the place where\n\
4786 a function returns a value.\n\
4788 On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.\n\
4789 (Actually, on most machines, scalar values are returned in the same\n\
4790 place regardless of mode.) The value of the expression is usually a\n\
4791 @code{reg} RTX for the hard register where the return value is stored.\n\
4792 The value can also be a @code{parallel} RTX, if the return value is in\n\
4793 multiple places. See @code{TARGET_FUNCTION_ARG} for an explanation of the\n\
4794 @code{parallel} form. Note that the callee will populate every\n\
4795 location specified in the @code{parallel}, but if the first element of\n\
4796 the @code{parallel} contains the whole return value, callers will use\n\
4797 that element as the canonical location and ignore the others. The m68k\n\
4798 port uses this type of @code{parallel} to return pointers in both\n\
4799 @samp{%a0} (the canonical location) and @samp{%d0}.\n\
4801 If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply\n\
4802 the same promotion rules specified in @code{PROMOTE_MODE} if\n\
4803 @var{valtype} is a scalar type.\n\
4805 If the precise function being called is known, @var{func} is a tree\n\
4806 node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null\n\
4807 pointer. This makes it possible to use a different value-returning\n\
4808 convention for specific functions when all their calls are\n\
4809 known.\n\
4811 Some target machines have ``register windows'' so that the register in\n\
4812 which a function returns its value is not the same as the one in which\n\
4813 the caller sees the value. For such machines, you should return\n\
4814 different RTX depending on @var{outgoing}.\n\
4816 @code{TARGET_FUNCTION_VALUE} is not used for return values with\n\
4817 aggregate data types, because these are returned in another way. See\n\
4818 @code{TARGET_STRUCT_VALUE_RTX} and related macros, below.",
4819 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
4820 default_function_value)
4822 /* Return the rtx for the result of a libcall of mode MODE,
4823 calling the function FN_NAME. */
4824 DEFHOOK
4825 (libcall_value,
4826 "Define this hook if the back-end needs to know the name of the libcall\n\
4827 function in order to determine where the result should be returned.\n\
4829 The mode of the result is given by @var{mode} and the name of the called\n\
4830 library function is given by @var{fun}. The hook should return an RTX\n\
4831 representing the place where the library function result will be returned.\n\
4833 If this hook is not defined, then LIBCALL_VALUE will be used.",
4834 rtx, (machine_mode mode, const_rtx fun),
4835 default_libcall_value)
4837 /* Return true if REGNO is a possible register number for
4838 a function value as seen by the caller. */
4839 DEFHOOK
4840 (function_value_regno_p,
4841 "A target hook that return @code{true} if @var{regno} is the number of a hard\n\
4842 register in which the values of called function may come back.\n\
4844 A register whose use for returning values is limited to serving as the\n\
4845 second of a pair (for a value of type @code{double}, say) need not be\n\
4846 recognized by this target hook.\n\
4848 If the machine has register windows, so that the caller and the called\n\
4849 function use different registers for the return value, this target hook\n\
4850 should recognize only the caller's register numbers.\n\
4852 If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.",
4853 bool, (const unsigned int regno),
4854 default_function_value_regno_p)
4856 /* ??? Documenting this hook requires a GFDL license grant. */
4857 DEFHOOK_UNDOC
4858 (internal_arg_pointer,
4859 "Return an rtx for the argument pointer incoming to the\
4860 current function.",
4861 rtx, (void),
4862 default_internal_arg_pointer)
4864 /* Update the current function stack boundary if needed. */
4865 DEFHOOK
4866 (update_stack_boundary,
4867 "Define this macro to update the current function stack boundary if\n\
4868 necessary.",
4869 void, (void), NULL)
4871 /* Handle stack alignment and return an rtx for Dynamic Realign
4872 Argument Pointer if necessary. */
4873 DEFHOOK
4874 (get_drap_rtx,
4875 "This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a\n\
4876 different argument pointer register is needed to access the function's\n\
4877 argument list due to stack realignment. Return @code{NULL} if no DRAP\n\
4878 is needed.",
4879 rtx, (void), NULL)
4881 /* Return true if all function parameters should be spilled to the
4882 stack. */
4883 DEFHOOK
4884 (allocate_stack_slots_for_args,
4885 "When optimization is disabled, this hook indicates whether or not\n\
4886 arguments should be allocated to stack slots. Normally, GCC allocates\n\
4887 stacks slots for arguments when not optimizing in order to make\n\
4888 debugging easier. However, when a function is declared with\n\
4889 @code{__attribute__((naked))}, there is no stack frame, and the compiler\n\
4890 cannot safely move arguments from the registers in which they are passed\n\
4891 to the stack. Therefore, this hook should return true in general, but\n\
4892 false for naked functions. The default implementation always returns true.",
4893 bool, (void),
4894 hook_bool_void_true)
4896 /* Return an rtx for the static chain for FNDECL_OR_TYPE. If INCOMING_P
4897 is true, then it should be for the callee; otherwise for the caller. */
4898 DEFHOOK
4899 (static_chain,
4900 "This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for\n\
4901 targets that may use different static chain locations for different\n\
4902 nested functions. This may be required if the target has function\n\
4903 attributes that affect the calling conventions of the function and\n\
4904 those calling conventions use different static chain locations.\n\
4906 The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.\n\
4908 If the static chain is passed in memory, this hook should be used to\n\
4909 provide rtx giving @code{mem} expressions that denote where they are stored.\n\
4910 Often the @code{mem} expression as seen by the caller will be at an offset\n\
4911 from the stack pointer and the @code{mem} expression as seen by the callee\n\
4912 will be at an offset from the frame pointer.\n\
4913 @findex stack_pointer_rtx\n\
4914 @findex frame_pointer_rtx\n\
4915 @findex arg_pointer_rtx\n\
4916 The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and\n\
4917 @code{arg_pointer_rtx} will have been initialized and should be used\n\
4918 to refer to those items.",
4919 rtx, (const_tree fndecl_or_type, bool incoming_p),
4920 default_static_chain)
4922 /* Fill in the trampoline at MEM with a call to FNDECL and a
4923 static chain value of CHAIN. */
4924 DEFHOOK
4925 (trampoline_init,
4926 "This hook is called to initialize a trampoline.\n\
4927 @var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}\n\
4928 is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an\n\
4929 RTX for the static chain value that should be passed to the function\n\
4930 when it is called.\n\
4932 If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the\n\
4933 first thing this hook should do is emit a block move into @var{m_tramp}\n\
4934 from the memory block returned by @code{assemble_trampoline_template}.\n\
4935 Note that the block move need only cover the constant parts of the\n\
4936 trampoline. If the target isolates the variable parts of the trampoline\n\
4937 to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.\n\
4939 If the target requires any other actions, such as flushing caches or\n\
4940 enabling stack execution, these actions should be performed after\n\
4941 initializing the trampoline proper.",
4942 void, (rtx m_tramp, tree fndecl, rtx static_chain),
4943 default_trampoline_init)
4945 /* Adjust the address of the trampoline in a target-specific way. */
4946 DEFHOOK
4947 (trampoline_adjust_address,
4948 "This hook should perform any machine-specific adjustment in\n\
4949 the address of the trampoline. Its argument contains the address of the\n\
4950 memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}. In case\n\
4951 the address to be used for a function call should be different from the\n\
4952 address at which the template was stored, the different address should\n\
4953 be returned; otherwise @var{addr} should be returned unchanged.\n\
4954 If this hook is not defined, @var{addr} will be used for function calls.",
4955 rtx, (rtx addr), NULL)
4957 DEFHOOKPOD
4958 (custom_function_descriptors,
4959 "This hook should be defined to a power of 2 if the target will benefit\n\
4960 from the use of custom descriptors for nested functions instead of the\n\
4961 standard trampolines. Such descriptors are created at run time on the\n\
4962 stack and made up of data only, but they are non-standard so the generated\n\
4963 code must be prepared to deal with them. This hook should be defined to 0\n\
4964 if the target uses function descriptors for its standard calling sequence,\n\
4965 like for example HP-PA or IA-64. Using descriptors for nested functions\n\
4966 eliminates the need for trampolines that reside on the stack and require\n\
4967 it to be made executable.\n\
4969 The value of the macro is used to parameterize the run-time identification\n\
4970 scheme implemented to distinguish descriptors from function addresses: it\n\
4971 gives the number of bytes by which their address is misaligned compared\n\
4972 with function addresses. The value of 1 will generally work, unless it is\n\
4973 already reserved by the target for another purpose, like for example on ARM.",\
4974 int, -1)
4976 /* Return the number of bytes of its own arguments that a function
4977 pops on returning, or 0 if the function pops no arguments and the
4978 caller must therefore pop them all after the function returns. */
4979 /* ??? tm.texi has no types for the parameters. */
4980 DEFHOOK
4981 (return_pops_args,
4982 "This target hook returns the number of bytes of its own arguments that\n\
4983 a function pops on returning, or 0 if the function pops no arguments\n\
4984 and the caller must therefore pop them all after the function returns.\n\
4986 @var{fundecl} is a C variable whose value is a tree node that describes\n\
4987 the function in question. Normally it is a node of type\n\
4988 @code{FUNCTION_DECL} that describes the declaration of the function.\n\
4989 From this you can obtain the @code{DECL_ATTRIBUTES} of the function.\n\
4991 @var{funtype} is a C variable whose value is a tree node that\n\
4992 describes the function in question. Normally it is a node of type\n\
4993 @code{FUNCTION_TYPE} that describes the data type of the function.\n\
4994 From this it is possible to obtain the data types of the value and\n\
4995 arguments (if known).\n\
4997 When a call to a library function is being considered, @var{fundecl}\n\
4998 will contain an identifier node for the library function. Thus, if\n\
4999 you need to distinguish among various library functions, you can do so\n\
5000 by their names. Note that ``library function'' in this context means\n\
5001 a function used to perform arithmetic, whose name is known specially\n\
5002 in the compiler and was not mentioned in the C code being compiled.\n\
5004 @var{size} is the number of bytes of arguments passed on the\n\
5005 stack. If a variable number of bytes is passed, it is zero, and\n\
5006 argument popping will always be the responsibility of the calling function.\n\
5008 On the VAX, all functions always pop their arguments, so the definition\n\
5009 of this macro is @var{size}. On the 68000, using the standard\n\
5010 calling convention, no functions pop their arguments, so the value of\n\
5011 the macro is always 0 in this case. But an alternative calling\n\
5012 convention is available in which functions that take a fixed number of\n\
5013 arguments pop them but other functions (such as @code{printf}) pop\n\
5014 nothing (the caller pops all). When this convention is in use,\n\
5015 @var{funtype} is examined to determine whether a function takes a fixed\n\
5016 number of arguments.",
5017 poly_int64, (tree fundecl, tree funtype, poly_int64 size),
5018 default_return_pops_args)
5020 /* Return a mode wide enough to copy any function value that might be
5021 returned. */
5022 DEFHOOK
5023 (get_raw_result_mode,
5024 "This target hook returns the mode to be used when accessing raw return\
5025 registers in @code{__builtin_return}. Define this macro if the value\
5026 in @var{reg_raw_mode} is not correct.",
5027 fixed_size_mode, (int regno),
5028 default_get_reg_raw_mode)
5030 /* Return a mode wide enough to copy any argument value that might be
5031 passed. */
5032 DEFHOOK
5033 (get_raw_arg_mode,
5034 "This target hook returns the mode to be used when accessing raw argument\
5035 registers in @code{__builtin_apply_args}. Define this macro if the value\
5036 in @var{reg_raw_mode} is not correct.",
5037 fixed_size_mode, (int regno),
5038 default_get_reg_raw_mode)
5040 /* Return true if a type is an empty record. */
5041 DEFHOOK
5042 (empty_record_p,
5043 "This target hook returns true if the type is an empty record. The default\n\
5044 is to return @code{false}.",
5045 bool, (const_tree type),
5046 hook_bool_const_tree_false)
5048 /* Warn about the change in empty class parameter passing ABI. */
5049 DEFHOOK
5050 (warn_parameter_passing_abi,
5051 "This target hook warns about the change in empty class parameter passing\n\
5052 ABI.",
5053 void, (cumulative_args_t ca, tree type),
5054 hook_void_CUMULATIVE_ARGS_tree)
5056 HOOK_VECTOR_END (calls)
5058 DEFHOOK
5059 (use_pseudo_pic_reg,
5060 "This hook should return 1 in case pseudo register should be created\n\
5061 for pic_offset_table_rtx during function expand.",
5062 bool, (void),
5063 hook_bool_void_false)
5065 DEFHOOK
5066 (init_pic_reg,
5067 "Perform a target dependent initialization of pic_offset_table_rtx.\n\
5068 This hook is called at the start of register allocation.",
5069 void, (void),
5070 hook_void_void)
5072 /* Return the diagnostic message string if conversion from FROMTYPE
5073 to TOTYPE is not allowed, NULL otherwise. */
5074 DEFHOOK
5075 (invalid_conversion,
5076 "If defined, this macro returns the diagnostic message when it is\n\
5077 invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}\n\
5078 if validity should be determined by the front end.",
5079 const char *, (const_tree fromtype, const_tree totype),
5080 hook_constcharptr_const_tree_const_tree_null)
5082 /* Return the diagnostic message string if the unary operation OP is
5083 not permitted on TYPE, NULL otherwise. */
5084 DEFHOOK
5085 (invalid_unary_op,
5086 "If defined, this macro returns the diagnostic message when it is\n\
5087 invalid to apply operation @var{op} (where unary plus is denoted by\n\
5088 @code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}\n\
5089 if validity should be determined by the front end.",
5090 const char *, (int op, const_tree type),
5091 hook_constcharptr_int_const_tree_null)
5093 /* Return the diagnostic message string if the binary operation OP
5094 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
5095 DEFHOOK
5096 (invalid_binary_op,
5097 "If defined, this macro returns the diagnostic message when it is\n\
5098 invalid to apply operation @var{op} to operands of types @var{type1}\n\
5099 and @var{type2}, or @code{NULL} if validity should be determined by\n\
5100 the front end.",
5101 const char *, (int op, const_tree type1, const_tree type2),
5102 hook_constcharptr_int_const_tree_const_tree_null)
5104 /* If values of TYPE are promoted to some other type when used in
5105 expressions (analogous to the integer promotions), return that type,
5106 or NULL_TREE otherwise. */
5107 DEFHOOK
5108 (promoted_type,
5109 "If defined, this target hook returns the type to which values of\n\
5110 @var{type} should be promoted when they appear in expressions,\n\
5111 analogous to the integer promotions, or @code{NULL_TREE} to use the\n\
5112 front end's normal promotion rules. This hook is useful when there are\n\
5113 target-specific types with special promotion rules.\n\
5114 This is currently used only by the C and C++ front ends.",
5115 tree, (const_tree type),
5116 hook_tree_const_tree_null)
5118 /* Convert EXPR to TYPE, if target-specific types with special conversion
5119 rules are involved. Return the converted expression, or NULL to apply
5120 the standard conversion rules. */
5121 DEFHOOK
5122 (convert_to_type,
5123 "If defined, this hook returns the result of converting @var{expr} to\n\
5124 @var{type}. It should return the converted expression,\n\
5125 or @code{NULL_TREE} to apply the front end's normal conversion rules.\n\
5126 This hook is useful when there are target-specific types with special\n\
5127 conversion rules.\n\
5128 This is currently used only by the C and C++ front ends.",
5129 tree, (tree type, tree expr),
5130 hook_tree_tree_tree_null)
5132 DEFHOOK
5133 (can_change_mode_class,
5134 "This hook returns true if it is possible to bitcast values held in\n\
5135 registers of class @var{rclass} from mode @var{from} to mode @var{to}\n\
5136 and if doing so preserves the low-order bits that are common to both modes.\n\
5137 The result is only meaningful if @var{rclass} has registers that can hold\n\
5138 both @code{from} and @code{to}. The default implementation returns true.\n\
5140 As an example of when such bitcasting is invalid, loading 32-bit integer or\n\
5141 floating-point objects into floating-point registers on Alpha extends them\n\
5142 to 64 bits. Therefore loading a 64-bit object and then storing it as a\n\
5143 32-bit object does not store the low-order 32 bits, as would be the case\n\
5144 for a normal register. Therefore, @file{alpha.h} defines\n\
5145 @code{TARGET_CAN_CHANGE_MODE_CLASS} to return:\n\
5147 @smallexample\n\
5148 (GET_MODE_SIZE (from) == GET_MODE_SIZE (to)\n\
5149 || !reg_classes_intersect_p (FLOAT_REGS, rclass))\n\
5150 @end smallexample\n\
5152 Even if storing from a register in mode @var{to} would be valid,\n\
5153 if both @var{from} and @code{raw_reg_mode} for @var{rclass} are wider\n\
5154 than @code{word_mode}, then we must prevent @var{to} narrowing the\n\
5155 mode. This happens when the middle-end assumes that it can load\n\
5156 or store pieces of an @var{N}-word pseudo, and that the pseudo will\n\
5157 eventually be allocated to @var{N} @code{word_mode} hard registers.\n\
5158 Failure to prevent this kind of mode change will result in the\n\
5159 entire @code{raw_reg_mode} being modified instead of the partial\n\
5160 value that the middle-end intended.",
5161 bool, (machine_mode from, machine_mode to, reg_class_t rclass),
5162 hook_bool_mode_mode_reg_class_t_true)
5164 /* Change pseudo allocno class calculated by IRA. */
5165 DEFHOOK
5166 (ira_change_pseudo_allocno_class,
5167 "A target hook which can change allocno class for given pseudo from\n\
5168 allocno and best class calculated by IRA.\n\
5170 The default version of this target hook always returns given class.",
5171 reg_class_t, (int, reg_class_t, reg_class_t),
5172 default_ira_change_pseudo_allocno_class)
5174 /* Return true if we use LRA instead of reload. */
5175 DEFHOOK
5176 (lra_p,
5177 "A target hook which returns true if we use LRA instead of reload pass.\
5179 The default version of this target hook returns true. New ports\
5180 should use LRA, and existing ports are encouraged to convert.",
5181 bool, (void),
5182 default_lra_p)
5184 /* Return register priority of given hard regno for the current target. */
5185 DEFHOOK
5186 (register_priority,
5187 "A target hook which returns the register priority number to which the\
5188 register @var{hard_regno} belongs to. The bigger the number, the\
5189 more preferable the hard register usage (when all other conditions are\
5190 the same). This hook can be used to prefer some hard register over\
5191 others in LRA. For example, some x86-64 register usage needs\
5192 additional prefix which makes instructions longer. The hook can\
5193 return lower priority number for such registers make them less favorable\
5194 and as result making the generated code smaller.\
5196 The default version of this target hook returns always zero.",
5197 int, (int),
5198 default_register_priority)
5200 /* Return true if we need register usage leveling. */
5201 DEFHOOK
5202 (register_usage_leveling_p,
5203 "A target hook which returns true if we need register usage leveling.\
5204 That means if a few hard registers are equally good for the\
5205 assignment, we choose the least used hard register. The register\
5206 usage leveling may be profitable for some targets. Don't use the\
5207 usage leveling for targets with conditional execution or targets\
5208 with big register files as it hurts if-conversion and cross-jumping\
5209 optimizations.\
5211 The default version of this target hook returns always false.",
5212 bool, (void),
5213 default_register_usage_leveling_p)
5215 /* Return true if maximal address displacement can be different. */
5216 DEFHOOK
5217 (different_addr_displacement_p,
5218 "A target hook which returns true if an address with the same structure\
5219 can have different maximal legitimate displacement. For example, the\
5220 displacement can depend on memory mode or on operand combinations in\
5221 the insn.\
5223 The default version of this target hook returns always false.",
5224 bool, (void),
5225 default_different_addr_displacement_p)
5227 /* Determine class for spilling pseudos of given mode into registers
5228 instead of memory. */
5229 DEFHOOK
5230 (spill_class,
5231 "This hook defines a class of registers which could be used for spilling\
5232 pseudos of the given mode and class, or @code{NO_REGS} if only memory\
5233 should be used. Not defining this hook is equivalent to returning\
5234 @code{NO_REGS} for all inputs.",
5235 reg_class_t, (reg_class_t, machine_mode),
5236 NULL)
5238 /* Determine an additional allocno class. */
5239 DEFHOOK
5240 (additional_allocno_class_p,
5241 "This hook should return @code{true} if given class of registers should\
5242 be an allocno class in any way. Usually RA uses only one register\
5243 class from all classes containing the same register set. In some\
5244 complicated cases, you need to have two or more such classes as\
5245 allocno ones for RA correct work. Not defining this hook is\
5246 equivalent to returning @code{false} for all inputs.",
5247 bool, (reg_class_t),
5248 hook_bool_reg_class_t_false)
5250 DEFHOOK
5251 (cstore_mode,
5252 "This hook defines the machine mode to use for the boolean result of\
5253 conditional store patterns. The ICODE argument is the instruction code\
5254 for the cstore being performed. Not definiting this hook is the same\
5255 as accepting the mode encoded into operand 0 of the cstore expander\
5256 patterns.",
5257 scalar_int_mode, (enum insn_code icode),
5258 default_cstore_mode)
5260 /* This target hook allows the backend to compute the register pressure
5261 classes to use. */
5262 DEFHOOK
5263 (compute_pressure_classes,
5264 "A target hook which lets a backend compute the set of pressure classes to\
5265 be used by those optimization passes which take register pressure into\
5266 account, as opposed to letting IRA compute them. It returns the number of\
5267 register classes stored in the array @var{pressure_classes}.",
5268 int, (enum reg_class *pressure_classes), NULL)
5270 /* True if a structure, union or array with MODE containing FIELD should
5271 be accessed using BLKmode. */
5272 DEFHOOK
5273 (member_type_forces_blk,
5274 "Return true if a structure, union or array containing @var{field} should\n\
5275 be accessed using @code{BLKMODE}.\n\
5277 If @var{field} is the only field in the structure, @var{mode} is its\n\
5278 mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the\n\
5279 case where structures of one field would require the structure's mode to\n\
5280 retain the field's mode.\n\
5282 Normally, this is not needed.",
5283 bool, (const_tree field, machine_mode mode),
5284 default_member_type_forces_blk)
5286 /* See tree-ssa-math-opts.c:divmod_candidate_p for conditions
5287 that gate the divod transform. */
5288 DEFHOOK
5289 (expand_divmod_libfunc,
5290 "Define this hook for enabling divmod transform if the port does not have\n\
5291 hardware divmod insn but defines target-specific divmod libfuncs.",
5292 void, (rtx libfunc, machine_mode mode, rtx op0, rtx op1, rtx *quot, rtx *rem),
5293 NULL)
5295 /* Return the class for a secondary reload, and fill in extra information. */
5296 DEFHOOK
5297 (secondary_reload,
5298 "Many machines have some registers that cannot be copied directly to or\n\
5299 from memory or even from other types of registers. An example is the\n\
5300 @samp{MQ} register, which on most machines, can only be copied to or\n\
5301 from general registers, but not memory. Below, we shall be using the\n\
5302 term 'intermediate register' when a move operation cannot be performed\n\
5303 directly, but has to be done by copying the source into the intermediate\n\
5304 register first, and then copying the intermediate register to the\n\
5305 destination. An intermediate register always has the same mode as\n\
5306 source and destination. Since it holds the actual value being copied,\n\
5307 reload might apply optimizations to re-use an intermediate register\n\
5308 and eliding the copy from the source when it can determine that the\n\
5309 intermediate register still holds the required value.\n\
5311 Another kind of secondary reload is required on some machines which\n\
5312 allow copying all registers to and from memory, but require a scratch\n\
5313 register for stores to some memory locations (e.g., those with symbolic\n\
5314 address on the RT, and those with certain symbolic address on the SPARC\n\
5315 when compiling PIC)@. Scratch registers need not have the same mode\n\
5316 as the value being copied, and usually hold a different value than\n\
5317 that being copied. Special patterns in the md file are needed to\n\
5318 describe how the copy is performed with the help of the scratch register;\n\
5319 these patterns also describe the number, register class(es) and mode(s)\n\
5320 of the scratch register(s).\n\
5322 In some cases, both an intermediate and a scratch register are required.\n\
5324 For input reloads, this target hook is called with nonzero @var{in_p},\n\
5325 and @var{x} is an rtx that needs to be copied to a register of class\n\
5326 @var{reload_class} in @var{reload_mode}. For output reloads, this target\n\
5327 hook is called with zero @var{in_p}, and a register of class @var{reload_class}\n\
5328 needs to be copied to rtx @var{x} in @var{reload_mode}.\n\
5330 If copying a register of @var{reload_class} from/to @var{x} requires\n\
5331 an intermediate register, the hook @code{secondary_reload} should\n\
5332 return the register class required for this intermediate register.\n\
5333 If no intermediate register is required, it should return NO_REGS.\n\
5334 If more than one intermediate register is required, describe the one\n\
5335 that is closest in the copy chain to the reload register.\n\
5337 If scratch registers are needed, you also have to describe how to\n\
5338 perform the copy from/to the reload register to/from this\n\
5339 closest intermediate register. Or if no intermediate register is\n\
5340 required, but still a scratch register is needed, describe the\n\
5341 copy from/to the reload register to/from the reload operand @var{x}.\n\
5343 You do this by setting @code{sri->icode} to the instruction code of a pattern\n\
5344 in the md file which performs the move. Operands 0 and 1 are the output\n\
5345 and input of this copy, respectively. Operands from operand 2 onward are\n\
5346 for scratch operands. These scratch operands must have a mode, and a\n\
5347 single-register-class\n\
5348 @c [later: or memory]\n\
5349 output constraint.\n\
5351 When an intermediate register is used, the @code{secondary_reload}\n\
5352 hook will be called again to determine how to copy the intermediate\n\
5353 register to/from the reload operand @var{x}, so your hook must also\n\
5354 have code to handle the register class of the intermediate operand.\n\
5356 @c [For later: maybe we'll allow multi-alternative reload patterns -\n\
5357 @c the port maintainer could name a mov<mode> pattern that has clobbers -\n\
5358 @c and match the constraints of input and output to determine the required\n\
5359 @c alternative. A restriction would be that constraints used to match\n\
5360 @c against reloads registers would have to be written as register class\n\
5361 @c constraints, or we need a new target macro / hook that tells us if an\n\
5362 @c arbitrary constraint can match an unknown register of a given class.\n\
5363 @c Such a macro / hook would also be useful in other places.]\n\
5366 @var{x} might be a pseudo-register or a @code{subreg} of a\n\
5367 pseudo-register, which could either be in a hard register or in memory.\n\
5368 Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is\n\
5369 in memory and the hard register number if it is in a register.\n\
5371 Scratch operands in memory (constraint @code{\"=m\"} / @code{\"=&m\"}) are\n\
5372 currently not supported. For the time being, you will have to continue\n\
5373 to use @code{TARGET_SECONDARY_MEMORY_NEEDED} for that purpose.\n\
5375 @code{copy_cost} also uses this target hook to find out how values are\n\
5376 copied. If you want it to include some extra cost for the need to allocate\n\
5377 (a) scratch register(s), set @code{sri->extra_cost} to the additional cost.\n\
5378 Or if two dependent moves are supposed to have a lower cost than the sum\n\
5379 of the individual moves due to expected fortuitous scheduling and/or special\n\
5380 forwarding logic, you can set @code{sri->extra_cost} to a negative amount.",
5381 reg_class_t,
5382 (bool in_p, rtx x, reg_class_t reload_class, machine_mode reload_mode,
5383 secondary_reload_info *sri),
5384 default_secondary_reload)
5386 DEFHOOK
5387 (secondary_memory_needed,
5388 "Certain machines have the property that some registers cannot be copied\n\
5389 to some other registers without using memory. Define this hook on\n\
5390 those machines to return true if objects of mode @var{m} in registers\n\
5391 of @var{class1} can only be copied to registers of class @var{class2} by\n\
5392 storing a register of @var{class1} into memory and loading that memory\n\
5393 location into a register of @var{class2}. The default definition returns\n\
5394 false for all inputs.",
5395 bool, (machine_mode mode, reg_class_t class1, reg_class_t class2),
5396 hook_bool_mode_reg_class_t_reg_class_t_false)
5398 DEFHOOK
5399 (secondary_memory_needed_mode,
5400 "If @code{TARGET_SECONDARY_MEMORY_NEEDED} tells the compiler to use memory\n\
5401 when moving between two particular registers of mode @var{mode},\n\
5402 this hook specifies the mode that the memory should have.\n\
5404 The default depends on @code{TARGET_LRA_P}. Without LRA, the default\n\
5405 is to use a word-sized mode for integral modes that are smaller than a\n\
5406 a word. This is right thing to do on most machines because it ensures\n\
5407 that all bits of the register are copied and prevents accesses to the\n\
5408 registers in a narrower mode, which some machines prohibit for\n\
5409 floating-point registers.\n\
5411 However, this default behavior is not correct on some machines, such as\n\
5412 the DEC Alpha, that store short integers in floating-point registers\n\
5413 differently than in integer registers. On those machines, the default\n\
5414 widening will not work correctly and you must define this hook to\n\
5415 suppress that widening in some cases. See the file @file{alpha.c} for\n\
5416 details.\n\
5418 With LRA, the default is to use @var{mode} unmodified.",
5419 machine_mode, (machine_mode mode),
5420 default_secondary_memory_needed_mode)
5422 /* Given an rtx X being reloaded into a reg required to be in class CLASS,
5423 return the class of reg to actually use. */
5424 DEFHOOK
5425 (preferred_reload_class,
5426 "A target hook that places additional restrictions on the register class\n\
5427 to use when it is necessary to copy value @var{x} into a register in class\n\
5428 @var{rclass}. The value is a register class; perhaps @var{rclass}, or perhaps\n\
5429 another, smaller class.\n\
5431 The default version of this hook always returns value of @code{rclass} argument.\n\
5433 Sometimes returning a more restrictive class makes better code. For\n\
5434 example, on the 68000, when @var{x} is an integer constant that is in range\n\
5435 for a @samp{moveq} instruction, the value of this macro is always\n\
5436 @code{DATA_REGS} as long as @var{rclass} includes the data registers.\n\
5437 Requiring a data register guarantees that a @samp{moveq} will be used.\n\
5439 One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return\n\
5440 @var{rclass} is if @var{x} is a legitimate constant which cannot be\n\
5441 loaded into some register class. By returning @code{NO_REGS} you can\n\
5442 force @var{x} into a memory location. For example, rs6000 can load\n\
5443 immediate values into general-purpose registers, but does not have an\n\
5444 instruction for loading an immediate value into a floating-point\n\
5445 register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when\n\
5446 @var{x} is a floating-point constant. If the constant can't be loaded\n\
5447 into any kind of register, code generation will be better if\n\
5448 @code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead\n\
5449 of using @code{TARGET_PREFERRED_RELOAD_CLASS}.\n\
5451 If an insn has pseudos in it after register allocation, reload will go\n\
5452 through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}\n\
5453 to find the best one. Returning @code{NO_REGS}, in this case, makes\n\
5454 reload add a @code{!} in front of the constraint: the x86 back-end uses\n\
5455 this feature to discourage usage of 387 registers when math is done in\n\
5456 the SSE registers (and vice versa).",
5457 reg_class_t,
5458 (rtx x, reg_class_t rclass),
5459 default_preferred_reload_class)
5461 /* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
5462 input reloads. */
5463 DEFHOOK
5464 (preferred_output_reload_class,
5465 "Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of\n\
5466 input reloads.\n\
5468 The default version of this hook always returns value of @code{rclass}\n\
5469 argument.\n\
5471 You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage\n\
5472 reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.",
5473 reg_class_t,
5474 (rtx x, reg_class_t rclass),
5475 default_preferred_output_reload_class)
5477 DEFHOOK
5478 (select_early_remat_modes,
5479 "On some targets, certain modes cannot be held in registers around a\n\
5480 standard ABI call and are relatively expensive to spill to the stack.\n\
5481 The early rematerialization pass can help in such cases by aggressively\n\
5482 recomputing values after calls, so that they don't need to be spilled.\n\
5484 This hook returns the set of such modes by setting the associated bits\n\
5485 in @var{modes}. The default implementation selects no modes, which has\n\
5486 the effect of disabling the early rematerialization pass.",
5487 void, (sbitmap modes),
5488 default_select_early_remat_modes)
5490 DEFHOOK
5491 (class_likely_spilled_p,
5492 "A target hook which returns @code{true} if pseudos that have been assigned\n\
5493 to registers of class @var{rclass} would likely be spilled because\n\
5494 registers of @var{rclass} are needed for spill registers.\n\
5496 The default version of this target hook returns @code{true} if @var{rclass}\n\
5497 has exactly one register and @code{false} otherwise. On most machines, this\n\
5498 default should be used. For generally register-starved machines, such as\n\
5499 i386, or machines with right register constraints, such as SH, this hook\n\
5500 can be used to avoid excessive spilling.\n\
5502 This hook is also used by some of the global intra-procedural code\n\
5503 transformations to throtle code motion, to avoid increasing register\n\
5504 pressure.",
5505 bool, (reg_class_t rclass),
5506 default_class_likely_spilled_p)
5508 /* Return the maximum number of consecutive registers
5509 needed to represent mode MODE in a register of class RCLASS. */
5510 DEFHOOK
5511 (class_max_nregs,
5512 "A target hook returns the maximum number of consecutive registers\n\
5513 of class @var{rclass} needed to hold a value of mode @var{mode}.\n\
5515 This is closely related to the macro @code{TARGET_HARD_REGNO_NREGS}.\n\
5516 In fact, the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},\n\
5517 @var{mode})} target hook should be the maximum value of\n\
5518 @code{TARGET_HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}\n\
5519 values in the class @var{rclass}.\n\
5521 This target hook helps control the handling of multiple-word values\n\
5522 in the reload pass.\n\
5524 The default version of this target hook returns the size of @var{mode}\n\
5525 in words.",
5526 unsigned char, (reg_class_t rclass, machine_mode mode),
5527 default_class_max_nregs)
5529 DEFHOOK
5530 (preferred_rename_class,
5531 "A target hook that places additional preference on the register\
5532 class to use when it is necessary to rename a register in class\
5533 @var{rclass} to another class, or perhaps @var{NO_REGS}, if no\
5534 preferred register class is found or hook @code{preferred_rename_class}\
5535 is not implemented.\
5536 Sometimes returning a more restrictive class makes better code. For\
5537 example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\
5538 smaller than instructions using @code{GENERIC_REGS}. By returning\
5539 @code{LO_REGS} from @code{preferred_rename_class}, code size can\
5540 be reduced.",
5541 reg_class_t, (reg_class_t rclass),
5542 default_preferred_rename_class)
5544 /* This target hook allows the backend to avoid unsafe substitution
5545 during register allocation. */
5546 DEFHOOK
5547 (cannot_substitute_mem_equiv_p,
5548 "A target hook which returns @code{true} if @var{subst} can't\n\
5549 substitute safely pseudos with equivalent memory values during\n\
5550 register allocation.\n\
5551 The default version of this target hook returns @code{false}.\n\
5552 On most machines, this default should be used. For generally\n\
5553 machines with non orthogonal register usage for addressing, such\n\
5554 as SH, this hook can be used to avoid excessive spilling.",
5555 bool, (rtx subst),
5556 hook_bool_rtx_false)
5558 /* This target hook allows the backend to legitimize base plus
5559 displacement addressing. */
5560 DEFHOOK
5561 (legitimize_address_displacement,
5562 "This hook tries to split address offset @var{orig_offset} into\n\
5563 two parts: one that should be added to the base address to create\n\
5564 a local anchor point, and an additional offset that can be applied\n\
5565 to the anchor to address a value of mode @var{mode}. The idea is that\n\
5566 the local anchor could be shared by other accesses to nearby locations.\n\
5568 The hook returns true if it succeeds, storing the offset of the\n\
5569 anchor from the base in @var{offset1} and the offset of the final address\n\
5570 from the anchor in @var{offset2}. The default implementation returns false.",
5571 bool, (rtx *offset1, rtx *offset2, poly_int64 orig_offset, machine_mode mode),
5572 default_legitimize_address_displacement)
5574 /* This target hook allows the backend to perform additional
5575 processing while initializing for variable expansion. */
5576 DEFHOOK
5577 (expand_to_rtl_hook,
5578 "This hook is called just before expansion into rtl, allowing the target\n\
5579 to perform additional initializations or analysis before the expansion.\n\
5580 For example, the rs6000 port uses it to allocate a scratch stack slot\n\
5581 for use in copying SDmode values between memory and floating point\n\
5582 registers whenever the function being expanded has any SDmode\n\
5583 usage.",
5584 void, (void),
5585 hook_void_void)
5587 /* This target hook allows the backend to perform additional
5588 instantiations on rtx that are not actually in insns yet,
5589 but will be later. */
5590 DEFHOOK
5591 (instantiate_decls,
5592 "This hook allows the backend to perform additional instantiations on rtl\n\
5593 that are not actually in any insns yet, but will be later.",
5594 void, (void),
5595 hook_void_void)
5597 DEFHOOK
5598 (hard_regno_nregs,
5599 "This hook returns the number of consecutive hard registers, starting\n\
5600 at register number @var{regno}, required to hold a value of mode\n\
5601 @var{mode}. This hook must never return zero, even if a register\n\
5602 cannot hold the requested mode - indicate that with\n\
5603 @code{TARGET_HARD_REGNO_MODE_OK} and/or\n\
5604 @code{TARGET_CAN_CHANGE_MODE_CLASS} instead.\n\
5606 The default definition returns the number of words in @var{mode}.",
5607 unsigned int, (unsigned int regno, machine_mode mode),
5608 default_hard_regno_nregs)
5610 DEFHOOK
5611 (hard_regno_mode_ok,
5612 "This hook returns true if it is permissible to store a value\n\
5613 of mode @var{mode} in hard register number @var{regno} (or in several\n\
5614 registers starting with that one). The default definition returns true\n\
5615 unconditionally.\n\
5617 You need not include code to check for the numbers of fixed registers,\n\
5618 because the allocation mechanism considers them to be always occupied.\n\
5620 @cindex register pairs\n\
5621 On some machines, double-precision values must be kept in even/odd\n\
5622 register pairs. You can implement that by defining this hook to reject\n\
5623 odd register numbers for such modes.\n\
5625 The minimum requirement for a mode to be OK in a register is that the\n\
5626 @samp{mov@var{mode}} instruction pattern support moves between the\n\
5627 register and other hard register in the same class and that moving a\n\
5628 value into the register and back out not alter it.\n\
5630 Since the same instruction used to move @code{word_mode} will work for\n\
5631 all narrower integer modes, it is not necessary on any machine for\n\
5632 this hook to distinguish between these modes, provided you define\n\
5633 patterns @samp{movhi}, etc., to take advantage of this. This is\n\
5634 useful because of the interaction between @code{TARGET_HARD_REGNO_MODE_OK}\n\
5635 and @code{TARGET_MODES_TIEABLE_P}; it is very desirable for all integer\n\
5636 modes to be tieable.\n\
5638 Many machines have special registers for floating point arithmetic.\n\
5639 Often people assume that floating point machine modes are allowed only\n\
5640 in floating point registers. This is not true. Any registers that\n\
5641 can hold integers can safely @emph{hold} a floating point machine\n\
5642 mode, whether or not floating arithmetic can be done on it in those\n\
5643 registers. Integer move instructions can be used to move the values.\n\
5645 On some machines, though, the converse is true: fixed-point machine\n\
5646 modes may not go in floating registers. This is true if the floating\n\
5647 registers normalize any value stored in them, because storing a\n\
5648 non-floating value there would garble it. In this case,\n\
5649 @code{TARGET_HARD_REGNO_MODE_OK} should reject fixed-point machine modes in\n\
5650 floating registers. But if the floating registers do not automatically\n\
5651 normalize, if you can store any bit pattern in one and retrieve it\n\
5652 unchanged without a trap, then any machine mode may go in a floating\n\
5653 register, so you can define this hook to say so.\n\
5655 The primary significance of special floating registers is rather that\n\
5656 they are the registers acceptable in floating point arithmetic\n\
5657 instructions. However, this is of no concern to\n\
5658 @code{TARGET_HARD_REGNO_MODE_OK}. You handle it by writing the proper\n\
5659 constraints for those instructions.\n\
5661 On some machines, the floating registers are especially slow to access,\n\
5662 so that it is better to store a value in a stack frame than in such a\n\
5663 register if floating point arithmetic is not being done. As long as the\n\
5664 floating registers are not in class @code{GENERAL_REGS}, they will not\n\
5665 be used unless some pattern's constraint asks for one.",
5666 bool, (unsigned int regno, machine_mode mode),
5667 hook_bool_uint_mode_true)
5669 DEFHOOK
5670 (modes_tieable_p,
5671 "This hook returns true if a value of mode @var{mode1} is accessible\n\
5672 in mode @var{mode2} without copying.\n\
5674 If @code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode1})} and\n\
5675 @code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode2})} are always\n\
5676 the same for any @var{r}, then\n\
5677 @code{TARGET_MODES_TIEABLE_P (@var{mode1}, @var{mode2})}\n\
5678 should be true. If they differ for any @var{r}, you should define\n\
5679 this hook to return false unless some other mechanism ensures the\n\
5680 accessibility of the value in a narrower mode.\n\
5682 You should define this hook to return true in as many cases as\n\
5683 possible since doing so will allow GCC to perform better register\n\
5684 allocation. The default definition returns true unconditionally.",
5685 bool, (machine_mode mode1, machine_mode mode2),
5686 hook_bool_mode_mode_true)
5688 /* Return true if is OK to use a hard register REGNO as scratch register
5689 in peephole2. */
5690 DEFHOOK
5691 (hard_regno_scratch_ok,
5692 "This target hook should return @code{true} if it is OK to use a hard register\n\
5693 @var{regno} as scratch reg in peephole2.\n\
5695 One common use of this macro is to prevent using of a register that\n\
5696 is not saved by a prologue in an interrupt handler.\n\
5698 The default version of this hook always returns @code{true}.",
5699 bool, (unsigned int regno),
5700 default_hard_regno_scratch_ok)
5702 DEFHOOK
5703 (hard_regno_call_part_clobbered,
5704 "This hook should return true if @var{regno} is partly call-saved and\n\
5705 partly call-clobbered, and if a value of mode @var{mode} would be partly\n\
5706 clobbered by a call. For example, if the low 32 bits of @var{regno} are\n\
5707 preserved across a call but higher bits are clobbered, this hook should\n\
5708 return true for a 64-bit mode but false for a 32-bit mode.\n\
5710 The default implementation returns false, which is correct\n\
5711 for targets that don't have partly call-clobbered registers.",
5712 bool, (unsigned int regno, machine_mode mode),
5713 hook_bool_uint_mode_false)
5715 /* Return the smallest number of different values for which it is best to
5716 use a jump-table instead of a tree of conditional branches. */
5717 DEFHOOK
5718 (case_values_threshold,
5719 "This function return the smallest number of different values for which it\n\
5720 is best to use a jump-table instead of a tree of conditional branches.\n\
5721 The default is four for machines with a @code{casesi} instruction and\n\
5722 five otherwise. This is best for most machines.",
5723 unsigned int, (void),
5724 default_case_values_threshold)
5726 DEFHOOK
5727 (starting_frame_offset,
5728 "This hook returns the offset from the frame pointer to the first local\n\
5729 variable slot to be allocated. If @code{FRAME_GROWS_DOWNWARD}, it is the\n\
5730 offset to @emph{end} of the first slot allocated, otherwise it is the\n\
5731 offset to @emph{beginning} of the first slot allocated. The default\n\
5732 implementation returns 0.",
5733 HOST_WIDE_INT, (void),
5734 hook_hwi_void_0)
5736 /* Optional callback to advise the target to compute the frame layout. */
5737 DEFHOOK
5738 (compute_frame_layout,
5739 "This target hook is called once each time the frame layout needs to be\n\
5740 recalculated. The calculations can be cached by the target and can then\n\
5741 be used by @code{INITIAL_ELIMINATION_OFFSET} instead of re-computing the\n\
5742 layout on every invocation of that hook. This is particularly useful\n\
5743 for targets that have an expensive frame layout function. Implementing\n\
5744 this callback is optional.",
5745 void, (void),
5746 hook_void_void)
5748 /* Return true if a function must have and use a frame pointer. */
5749 DEFHOOK
5750 (frame_pointer_required,
5751 "This target hook should return @code{true} if a function must have and use\n\
5752 a frame pointer. This target hook is called in the reload pass. If its return\n\
5753 value is @code{true} the function will have a frame pointer.\n\
5755 This target hook can in principle examine the current function and decide\n\
5756 according to the facts, but on most machines the constant @code{false} or the\n\
5757 constant @code{true} suffices. Use @code{false} when the machine allows code\n\
5758 to be generated with no frame pointer, and doing so saves some time or space.\n\
5759 Use @code{true} when there is no possible advantage to avoiding a frame\n\
5760 pointer.\n\
5762 In certain cases, the compiler does not know how to produce valid code\n\
5763 without a frame pointer. The compiler recognizes those cases and\n\
5764 automatically gives the function a frame pointer regardless of what\n\
5765 @code{targetm.frame_pointer_required} returns. You don't need to worry about\n\
5766 them.\n\
5768 In a function that does not require a frame pointer, the frame pointer\n\
5769 register can be allocated for ordinary usage, unless you mark it as a\n\
5770 fixed register. See @code{FIXED_REGISTERS} for more information.\n\
5772 Default return value is @code{false}.",
5773 bool, (void),
5774 hook_bool_void_false)
5776 /* Returns true if the compiler is allowed to try to replace register number
5777 from-reg with register number to-reg. */
5778 DEFHOOK
5779 (can_eliminate,
5780 "This target hook should return @code{true} if the compiler is allowed to\n\
5781 try to replace register number @var{from_reg} with register number\n\
5782 @var{to_reg}. This target hook will usually be @code{true}, since most of the\n\
5783 cases preventing register elimination are things that the compiler already\n\
5784 knows about.\n\
5786 Default return value is @code{true}.",
5787 bool, (const int from_reg, const int to_reg),
5788 hook_bool_const_int_const_int_true)
5790 /* Modify any or all of fixed_regs, call_used_regs, global_regs,
5791 reg_names, and reg_class_contents to account of the vagaries of the
5792 target. */
5793 DEFHOOK
5794 (conditional_register_usage,
5795 "This hook may conditionally modify five variables\n\
5796 @code{fixed_regs}, @code{call_used_regs}, @code{global_regs},\n\
5797 @code{reg_names}, and @code{reg_class_contents}, to take into account\n\
5798 any dependence of these register sets on target flags. The first three\n\
5799 of these are of type @code{char []} (interpreted as boolean vectors).\n\
5800 @code{global_regs} is a @code{const char *[]}, and\n\
5801 @code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is\n\
5802 called, @code{fixed_regs}, @code{call_used_regs},\n\
5803 @code{reg_class_contents}, and @code{reg_names} have been initialized\n\
5804 from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},\n\
5805 @code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.\n\
5806 @code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},\n\
5807 @option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}\n\
5808 command options have been applied.\n\
5810 @cindex disabling certain registers\n\
5811 @cindex controlling register usage\n\
5812 If the usage of an entire class of registers depends on the target\n\
5813 flags, you may indicate this to GCC by using this macro to modify\n\
5814 @code{fixed_regs} and @code{call_used_regs} to 1 for each of the\n\
5815 registers in the classes which should not be used by GCC@. Also make\n\
5816 @code{define_register_constraint}s return @code{NO_REGS} for constraints\n\
5817 that shouldn't be used.\n\
5819 (However, if this class is not included in @code{GENERAL_REGS} and all\n\
5820 of the insn patterns whose constraints permit this class are\n\
5821 controlled by target switches, then GCC will automatically avoid using\n\
5822 these registers when the target switches are opposed to them.)",
5823 void, (void),
5824 hook_void_void)
5826 DEFHOOK
5827 (stack_clash_protection_final_dynamic_probe,
5828 "Some targets make optimistic assumptions about the state of stack probing when they emit their prologues. On such targets a probe into the end of any dynamically allocated space is likely required for safety against stack clash style attacks. Define this variable to return nonzero if such a probe is required or zero otherwise. You need not define this macro if it would always have the value zero.",
5829 bool, (rtx residual),
5830 default_stack_clash_protection_final_dynamic_probe)
5833 /* Functions specific to the C family of frontends. */
5834 #undef HOOK_PREFIX
5835 #define HOOK_PREFIX "TARGET_C_"
5836 HOOK_VECTOR (TARGET_C, c)
5838 /* ??? Documenting this hook requires a GFDL license grant. */
5839 DEFHOOK_UNDOC
5840 (mode_for_suffix,
5841 "Return machine mode for non-standard constant literal suffix @var{c},\
5842 or VOIDmode if non-standard suffixes are unsupported.",
5843 machine_mode, (char c),
5844 default_mode_for_suffix)
5846 DEFHOOK
5847 (excess_precision,
5848 "Return a value, with the same meaning as the C99 macro\
5849 @code{FLT_EVAL_METHOD} that describes which excess precision should be\
5850 applied. @var{type} is either @code{EXCESS_PRECISION_TYPE_IMPLICIT},\
5851 @code{EXCESS_PRECISION_TYPE_FAST}, or\
5852 @code{EXCESS_PRECISION_TYPE_STANDARD}. For\
5853 @code{EXCESS_PRECISION_TYPE_IMPLICIT}, the target should return which\
5854 precision and range operations will be implictly evaluated in regardless\
5855 of the excess precision explicitly added. For\
5856 @code{EXCESS_PRECISION_TYPE_STANDARD} and\
5857 @code{EXCESS_PRECISION_TYPE_FAST}, the target should return the\
5858 explicit excess precision that should be added depending on the\
5859 value set for @option{-fexcess-precision=@r{[}standard@r{|}fast@r{]}}.\
5860 Note that unpredictable explicit excess precision does not make sense,\
5861 so a target should never return @code{FLT_EVAL_METHOD_UNPREDICTABLE}\
5862 when @var{type} is @code{EXCESS_PRECISION_TYPE_STANDARD} or\
5863 @code{EXCESS_PRECISION_TYPE_FAST}.",
5864 enum flt_eval_method, (enum excess_precision_type type),
5865 default_excess_precision)
5867 HOOK_VECTOR_END (c)
5869 /* Functions specific to the C++ frontend. */
5870 #undef HOOK_PREFIX
5871 #define HOOK_PREFIX "TARGET_CXX_"
5872 HOOK_VECTOR (TARGET_CXX, cxx)
5874 /* Return the integer type used for guard variables. */
5875 DEFHOOK
5876 (guard_type,
5877 "Define this hook to override the integer type used for guard variables.\n\
5878 These are used to implement one-time construction of static objects. The\n\
5879 default is long_long_integer_type_node.",
5880 tree, (void),
5881 default_cxx_guard_type)
5883 /* Return true if only the low bit of the guard should be tested. */
5884 DEFHOOK
5885 (guard_mask_bit,
5886 "This hook determines how guard variables are used. It should return\n\
5887 @code{false} (the default) if the first byte should be used. A return value of\n\
5888 @code{true} indicates that only the least significant bit should be used.",
5889 bool, (void),
5890 hook_bool_void_false)
5892 /* Returns the size of the array cookie for an array of type. */
5893 DEFHOOK
5894 (get_cookie_size,
5895 "This hook returns the size of the cookie to use when allocating an array\n\
5896 whose elements have the indicated @var{type}. Assumes that it is already\n\
5897 known that a cookie is needed. The default is\n\
5898 @code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the\n\
5899 IA64/Generic C++ ABI@.",
5900 tree, (tree type),
5901 default_cxx_get_cookie_size)
5903 /* Returns true if the element size should be stored in the array cookie. */
5904 DEFHOOK
5905 (cookie_has_size,
5906 "This hook should return @code{true} if the element size should be stored in\n\
5907 array cookies. The default is to return @code{false}.",
5908 bool, (void),
5909 hook_bool_void_false)
5911 /* Allows backends to perform additional processing when
5912 deciding if a class should be exported or imported. */
5913 DEFHOOK
5914 (import_export_class,
5915 "If defined by a backend this hook allows the decision made to export\n\
5916 class @var{type} to be overruled. Upon entry @var{import_export}\n\
5917 will contain 1 if the class is going to be exported, @minus{}1 if it is going\n\
5918 to be imported and 0 otherwise. This function should return the\n\
5919 modified value and perform any other actions necessary to support the\n\
5920 backend's targeted operating system.",
5921 int, (tree type, int import_export), NULL)
5923 /* Returns true if constructors and destructors return "this". */
5924 DEFHOOK
5925 (cdtor_returns_this,
5926 "This hook should return @code{true} if constructors and destructors return\n\
5927 the address of the object created/destroyed. The default is to return\n\
5928 @code{false}.",
5929 bool, (void),
5930 hook_bool_void_false)
5932 /* Returns true if the key method for a class can be an inline
5933 function, so long as it is not declared inline in the class
5934 itself. Returning true is the behavior required by the Itanium C++ ABI. */
5935 DEFHOOK
5936 (key_method_may_be_inline,
5937 "This hook returns true if the key method for a class (i.e., the method\n\
5938 which, if defined in the current translation unit, causes the virtual\n\
5939 table to be emitted) may be an inline function. Under the standard\n\
5940 Itanium C++ ABI the key method may be an inline function so long as\n\
5941 the function is not declared inline in the class definition. Under\n\
5942 some variants of the ABI, an inline function can never be the key\n\
5943 method. The default is to return @code{true}.",
5944 bool, (void),
5945 hook_bool_void_true)
5947 DEFHOOK
5948 (determine_class_data_visibility,
5949 "@var{decl} is a virtual table, virtual table table, typeinfo object,\
5950 or other similar implicit class data object that will be emitted with\
5951 external linkage in this translation unit. No ELF visibility has been\
5952 explicitly specified. If the target needs to specify a visibility\
5953 other than that of the containing class, use this hook to set\
5954 @code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
5955 void, (tree decl),
5956 hook_void_tree)
5958 /* Returns true (the default) if virtual tables and other
5959 similar implicit class data objects are always COMDAT if they
5960 have external linkage. If this hook returns false, then
5961 class data for classes whose virtual table will be emitted in
5962 only one translation unit will not be COMDAT. */
5963 DEFHOOK
5964 (class_data_always_comdat,
5965 "This hook returns true (the default) if virtual tables and other\n\
5966 similar implicit class data objects are always COMDAT if they have\n\
5967 external linkage. If this hook returns false, then class data for\n\
5968 classes whose virtual table will be emitted in only one translation\n\
5969 unit will not be COMDAT.",
5970 bool, (void),
5971 hook_bool_void_true)
5973 /* Returns true (the default) if the RTTI for the basic types,
5974 which is always defined in the C++ runtime, should be COMDAT;
5975 false if it should not be COMDAT. */
5976 DEFHOOK
5977 (library_rtti_comdat,
5978 "This hook returns true (the default) if the RTTI information for\n\
5979 the basic types which is defined in the C++ runtime should always\n\
5980 be COMDAT, false if it should not be COMDAT.",
5981 bool, (void),
5982 hook_bool_void_true)
5984 /* Returns true if __aeabi_atexit should be used to register static
5985 destructors. */
5986 DEFHOOK
5987 (use_aeabi_atexit,
5988 "This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)\n\
5989 should be used to register static destructors when @option{-fuse-cxa-atexit}\n\
5990 is in effect. The default is to return false to use @code{__cxa_atexit}.",
5991 bool, (void),
5992 hook_bool_void_false)
5994 /* Returns true if target may use atexit in the same manner as
5995 __cxa_atexit to register static destructors. */
5996 DEFHOOK
5997 (use_atexit_for_cxa_atexit,
5998 "This hook returns true if the target @code{atexit} function can be used\n\
5999 in the same manner as @code{__cxa_atexit} to register C++ static\n\
6000 destructors. This requires that @code{atexit}-registered functions in\n\
6001 shared libraries are run in the correct order when the libraries are\n\
6002 unloaded. The default is to return false.",
6003 bool, (void),
6004 hook_bool_void_false)
6006 DEFHOOK
6007 (adjust_class_at_definition,
6008 "@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\
6009 been defined. Use this hook to make adjustments to the class (eg, tweak\
6010 visibility or perform any other required target modifications).",
6011 void, (tree type),
6012 hook_void_tree)
6014 DEFHOOK
6015 (decl_mangling_context,
6016 "Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
6017 tree, (const_tree decl),
6018 hook_tree_const_tree_null)
6020 HOOK_VECTOR_END (cxx)
6022 /* Functions and data for emulated TLS support. */
6023 #undef HOOK_PREFIX
6024 #define HOOK_PREFIX "TARGET_EMUTLS_"
6025 HOOK_VECTOR (TARGET_EMUTLS, emutls)
6027 /* Name of the address and common functions. */
6028 DEFHOOKPOD
6029 (get_address,
6030 "Contains the name of the helper function that uses a TLS control\n\
6031 object to locate a TLS instance. The default causes libgcc's\n\
6032 emulated TLS helper function to be used.",
6033 const char *, "__builtin___emutls_get_address")
6035 DEFHOOKPOD
6036 (register_common,
6037 "Contains the name of the helper function that should be used at\n\
6038 program startup to register TLS objects that are implicitly\n\
6039 initialized to zero. If this is @code{NULL}, all TLS objects will\n\
6040 have explicit initializers. The default causes libgcc's emulated TLS\n\
6041 registration function to be used.",
6042 const char *, "__builtin___emutls_register_common")
6044 /* Prefixes for proxy variable and template. */
6045 DEFHOOKPOD
6046 (var_section,
6047 "Contains the name of the section in which TLS control variables should\n\
6048 be placed. The default of @code{NULL} allows these to be placed in\n\
6049 any section.",
6050 const char *, NULL)
6052 DEFHOOKPOD
6053 (tmpl_section,
6054 "Contains the name of the section in which TLS initializers should be\n\
6055 placed. The default of @code{NULL} allows these to be placed in any\n\
6056 section.",
6057 const char *, NULL)
6059 /* Prefixes for proxy variable and template. */
6060 DEFHOOKPOD
6061 (var_prefix,
6062 "Contains the prefix to be prepended to TLS control variable names.\n\
6063 The default of @code{NULL} uses a target-specific prefix.",
6064 const char *, NULL)
6066 DEFHOOKPOD
6067 (tmpl_prefix,
6068 "Contains the prefix to be prepended to TLS initializer objects. The\n\
6069 default of @code{NULL} uses a target-specific prefix.",
6070 const char *, NULL)
6072 /* Function to generate field definitions of the proxy variable. */
6073 DEFHOOK
6074 (var_fields,
6075 "Specifies a function that generates the FIELD_DECLs for a TLS control\n\
6076 object type. @var{type} is the RECORD_TYPE the fields are for and\n\
6077 @var{name} should be filled with the structure tag, if the default of\n\
6078 @code{__emutls_object} is unsuitable. The default creates a type suitable\n\
6079 for libgcc's emulated TLS function.",
6080 tree, (tree type, tree *name),
6081 default_emutls_var_fields)
6083 /* Function to initialize a proxy variable. */
6084 DEFHOOK
6085 (var_init,
6086 "Specifies a function that generates the CONSTRUCTOR to initialize a\n\
6087 TLS control object. @var{var} is the TLS control object, @var{decl}\n\
6088 is the TLS object and @var{tmpl_addr} is the address of the\n\
6089 initializer. The default initializes libgcc's emulated TLS control object.",
6090 tree, (tree var, tree decl, tree tmpl_addr),
6091 default_emutls_var_init)
6093 /* Whether we are allowed to alter the usual alignment of the
6094 proxy variable. */
6095 DEFHOOKPOD
6096 (var_align_fixed,
6097 "Specifies whether the alignment of TLS control variable objects is\n\
6098 fixed and should not be increased as some backends may do to optimize\n\
6099 single objects. The default is false.",
6100 bool, false)
6102 /* Whether we can emit debug information for TLS vars. */
6103 DEFHOOKPOD
6104 (debug_form_tls_address,
6105 "Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor\n\
6106 may be used to describe emulated TLS control objects.",
6107 bool, false)
6109 HOOK_VECTOR_END (emutls)
6111 #undef HOOK_PREFIX
6112 #define HOOK_PREFIX "TARGET_OPTION_"
6113 HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)
6115 /* Function to validate the attribute((target(...))) strings. If
6116 the option is validated, the hook should also fill in
6117 DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
6118 DEFHOOK
6119 (valid_attribute_p,
6120 "This hook is called to parse @code{attribute(target(\"...\"))}, which\n\
6121 allows setting target-specific options on individual functions.\n\
6122 These function-specific options may differ\n\
6123 from the options specified on the command line. The hook should return\n\
6124 @code{true} if the options are valid.\n\
6126 The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
6127 the function declaration to hold a pointer to a target-specific\n\
6128 @code{struct cl_target_option} structure.",
6129 bool, (tree fndecl, tree name, tree args, int flags),
6130 default_target_option_valid_attribute_p)
6132 /* Function to save any extra target state in the target options structure. */
6133 DEFHOOK
6134 (save,
6135 "This hook is called to save any additional target-specific information\n\
6136 in the @code{struct cl_target_option} structure for function-specific\n\
6137 options from the @code{struct gcc_options} structure.\n\
6138 @xref{Option file format}.",
6139 void, (struct cl_target_option *ptr, struct gcc_options *opts), NULL)
6141 /* Function to restore any extra target state from the target options
6142 structure. */
6143 DEFHOOK
6144 (restore,
6145 "This hook is called to restore any additional target-specific\n\
6146 information in the @code{struct cl_target_option} structure for\n\
6147 function-specific options to the @code{struct gcc_options} structure.",
6148 void, (struct gcc_options *opts, struct cl_target_option *ptr), NULL)
6150 /* Function to update target-specific option information after being
6151 streamed in. */
6152 DEFHOOK
6153 (post_stream_in,
6154 "This hook is called to update target-specific information in the\n\
6155 @code{struct cl_target_option} structure after it is streamed in from\n\
6156 LTO bytecode.",
6157 void, (struct cl_target_option *ptr), NULL)
6159 /* Function to print any extra target state from the target options
6160 structure. */
6161 DEFHOOK
6162 (print,
6163 "This hook is called to print any additional target-specific\n\
6164 information in the @code{struct cl_target_option} structure for\n\
6165 function-specific options.",
6166 void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)
6168 /* Function to parse arguments to be validated for #pragma target, and to
6169 change the state if the options are valid. If the first argument is
6170 NULL, the second argument specifies the default options to use. Return
6171 true if the options are valid, and set the current state. */
6172 DEFHOOK
6173 (pragma_parse,
6174 "This target hook parses the options for @code{#pragma GCC target}, which\n\
6175 sets the target-specific options for functions that occur later in the\n\
6176 input stream. The options accepted should be the same as those handled by the\n\
6177 @code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.",
6178 bool, (tree args, tree pop_target),
6179 default_target_option_pragma_parse)
6181 /* Do option overrides for the target. */
6182 DEFHOOK
6183 (override,
6184 "Sometimes certain combinations of command options do not make sense on\n\
6185 a particular target machine. You can override the hook\n\
6186 @code{TARGET_OPTION_OVERRIDE} to take account of this. This hooks is called\n\
6187 once just after all the command options have been parsed.\n\
6189 Don't use this hook to turn on various extra optimizations for\n\
6190 @option{-O}. That is what @code{TARGET_OPTION_OPTIMIZATION} is for.\n\
6192 If you need to do something whenever the optimization level is\n\
6193 changed via the optimize attribute or pragma, see\n\
6194 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}",
6195 void, (void),
6196 hook_void_void)
6198 /* This function returns true if DECL1 and DECL2 are versions of the same
6199 function. DECL1 and DECL2 are function versions if and only if they
6200 have the same function signature and different target specific attributes,
6201 that is, they are compiled for different target machines. */
6202 DEFHOOK
6203 (function_versions,
6204 "This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are\n\
6205 versions of the same function. @var{DECL1} and @var{DECL2} are function\n\
6206 versions if and only if they have the same function signature and\n\
6207 different target specific attributes, that is, they are compiled for\n\
6208 different target machines.",
6209 bool, (tree decl1, tree decl2),
6210 hook_bool_tree_tree_false)
6212 /* Function to determine if one function can inline another function. */
6213 #undef HOOK_PREFIX
6214 #define HOOK_PREFIX "TARGET_"
6215 DEFHOOK
6216 (can_inline_p,
6217 "This target hook returns @code{false} if the @var{caller} function\n\
6218 cannot inline @var{callee}, based on target specific information. By\n\
6219 default, inlining is not allowed if the callee function has function\n\
6220 specific target options and the caller does not use the same options.",
6221 bool, (tree caller, tree callee),
6222 default_target_can_inline_p)
6224 DEFHOOK
6225 (relayout_function,
6226 "This target hook fixes function @var{fndecl} after attributes are processed. Default does nothing. On ARM, the default function's alignment is updated with the attribute target.",
6227 void, (tree fndecl),
6228 hook_void_tree)
6230 HOOK_VECTOR_END (target_option)
6232 /* For targets that need to mark extra registers as live on entry to
6233 the function, they should define this target hook and set their
6234 bits in the bitmap passed in. */
6235 DEFHOOK
6236 (extra_live_on_entry,
6237 "Add any hard registers to @var{regs} that are live on entry to the\n\
6238 function. This hook only needs to be defined to provide registers that\n\
6239 cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved\n\
6240 registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,\n\
6241 TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,\n\
6242 FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.",
6243 void, (bitmap regs),
6244 hook_void_bitmap)
6246 /* Targets should define this target hook to mark that non-callee clobbers are
6247 present in CALL_INSN_FUNCTION_USAGE for all the calls that bind to a local
6248 definition. */
6249 DEFHOOKPOD
6250 (call_fusage_contains_non_callee_clobbers,
6251 "Set to true if each call that binds to a local definition explicitly\n\
6252 clobbers or sets all non-fixed registers modified by performing the call.\n\
6253 That is, by the call pattern itself, or by code that might be inserted by the\n\
6254 linker (e.g. stubs, veneers, branch islands), but not including those\n\
6255 modifiable by the callee. The affected registers may be mentioned explicitly\n\
6256 in the call pattern, or included as clobbers in CALL_INSN_FUNCTION_USAGE.\n\
6257 The default version of this hook is set to false. The purpose of this hook\n\
6258 is to enable the fipa-ra optimization.",
6259 bool,
6260 false)
6262 /* Fill in additional registers set up by prologue into a regset. */
6263 DEFHOOK
6264 (set_up_by_prologue,
6265 "This hook should add additional registers that are computed by the prologue\
6266 to the hard regset for shrink-wrapping optimization purposes.",
6267 void, (struct hard_reg_set_container *),
6268 NULL)
6270 /* For targets that have attributes that can affect whether a
6271 function's return statements need checking. For instance a 'naked'
6272 function attribute. */
6273 DEFHOOK
6274 (warn_func_return,
6275 "True if a function's return statements should be checked for matching the function's return type. This includes checking for falling off the end of a non-void function. Return false if no such check should be made.",
6276 bool, (tree),
6277 hook_bool_tree_true)
6279 #undef HOOK_PREFIX
6280 #define HOOK_PREFIX "TARGET_SHRINK_WRAP_"
6281 HOOK_VECTOR (TARGET_SHRINK_WRAP_HOOKS, shrink_wrap)
6283 DEFHOOK
6284 (get_separate_components,
6285 "This hook should return an @code{sbitmap} with the bits set for those\n\
6286 components that can be separately shrink-wrapped in the current function.\n\
6287 Return @code{NULL} if the current function should not get any separate\n\
6288 shrink-wrapping.\n\
6289 Don't define this hook if it would always return @code{NULL}.\n\
6290 If it is defined, the other hooks in this group have to be defined as well.",
6291 sbitmap, (void),
6292 NULL)
6294 DEFHOOK
6295 (components_for_bb,
6296 "This hook should return an @code{sbitmap} with the bits set for those\n\
6297 components where either the prologue component has to be executed before\n\
6298 the @code{basic_block}, or the epilogue component after it, or both.",
6299 sbitmap, (basic_block),
6300 NULL)
6302 DEFHOOK
6303 (disqualify_components,
6304 "This hook should clear the bits in the @var{components} bitmap for those\n\
6305 components in @var{edge_components} that the target cannot handle on edge\n\
6306 @var{e}, where @var{is_prologue} says if this is for a prologue or an\n\
6307 epilogue instead.",
6308 void, (sbitmap components, edge e, sbitmap edge_components, bool is_prologue),
6309 NULL)
6311 DEFHOOK
6312 (emit_prologue_components,
6313 "Emit prologue insns for the components indicated by the parameter.",
6314 void, (sbitmap),
6315 NULL)
6317 DEFHOOK
6318 (emit_epilogue_components,
6319 "Emit epilogue insns for the components indicated by the parameter.",
6320 void, (sbitmap),
6321 NULL)
6323 DEFHOOK
6324 (set_handled_components,
6325 "Mark the components in the parameter as handled, so that the\n\
6326 @code{prologue} and @code{epilogue} named patterns know to ignore those\n\
6327 components. The target code should not hang on to the @code{sbitmap}, it\n\
6328 will be deleted after this call.",
6329 void, (sbitmap),
6330 NULL)
6332 HOOK_VECTOR_END (shrink_wrap)
6333 #undef HOOK_PREFIX
6334 #define HOOK_PREFIX "TARGET_"
6336 /* Determine the type of unwind info to emit for debugging. */
6337 DEFHOOK
6338 (debug_unwind_info,
6339 "This hook defines the mechanism that will be used for describing frame\n\
6340 unwind information to the debugger. Normally the hook will return\n\
6341 @code{UI_DWARF2} if DWARF 2 debug information is enabled, and\n\
6342 return @code{UI_NONE} otherwise.\n\
6344 A target may return @code{UI_DWARF2} even when DWARF 2 debug information\n\
6345 is disabled in order to always output DWARF 2 frame information.\n\
6347 A target may return @code{UI_TARGET} if it has ABI specified unwind tables.\n\
6348 This will suppress generation of the normal debug frame unwind information.",
6349 enum unwind_info_type, (void),
6350 default_debug_unwind_info)
6352 DEFHOOK
6353 (reset_location_view, "\
6354 This hook, if defined, enables -ginternal-reset-location-views, and\n\
6355 uses its result to override cases in which the estimated min insn\n\
6356 length might be nonzero even when a PC advance (i.e., a view reset)\n\
6357 cannot be taken for granted.\n\
6359 If the hook is defined, it must return a positive value to indicate\n\
6360 the insn definitely advances the PC, and so the view number can be\n\
6361 safely assumed to be reset; a negative value to mean the insn\n\
6362 definitely does not advance the PC, and os the view number must not\n\
6363 be reset; or zero to decide based on the estimated insn length.\n\
6365 If insn length is to be regarded as reliable, set the hook to\n\
6366 @code{hook_int_rtx_insn_0}.",
6367 int, (rtx_insn *), NULL)
6369 /* The code parameter should be of type enum rtx_code but this is not
6370 defined at this time. */
6371 DEFHOOK
6372 (canonicalize_comparison,
6373 "On some machines not all possible comparisons are defined, but you can\n\
6374 convert an invalid comparison into a valid one. For example, the Alpha\n\
6375 does not have a @code{GT} comparison, but you can use an @code{LT}\n\
6376 comparison instead and swap the order of the operands.\n\
6378 On such machines, implement this hook to do any required conversions.\n\
6379 @var{code} is the initial comparison code and @var{op0} and @var{op1}\n\
6380 are the left and right operands of the comparison, respectively. If\n\
6381 @var{op0_preserve_value} is @code{true} the implementation is not\n\
6382 allowed to change the value of @var{op0} since the value might be used\n\
6383 in RTXs which aren't comparisons. E.g. the implementation is not\n\
6384 allowed to swap operands in that case.\n\
6386 GCC will not assume that the comparison resulting from this macro is\n\
6387 valid but will see if the resulting insn matches a pattern in the\n\
6388 @file{md} file.\n\
6390 You need not to implement this hook if it would never change the\n\
6391 comparison code or operands.",
6392 void, (int *code, rtx *op0, rtx *op1, bool op0_preserve_value),
6393 default_canonicalize_comparison)
6395 DEFHOOK
6396 (min_arithmetic_precision,
6397 "On some RISC architectures with 64-bit registers, the processor also\n\
6398 maintains 32-bit condition codes that make it possible to do real 32-bit\n\
6399 arithmetic, although the operations are performed on the full registers.\n\
6401 On such architectures, defining this hook to 32 tells the compiler to try\n\
6402 using 32-bit arithmetical operations setting the condition codes instead\n\
6403 of doing full 64-bit arithmetic.\n\
6405 More generally, define this hook on RISC architectures if you want the\n\
6406 compiler to try using arithmetical operations setting the condition codes\n\
6407 with a precision lower than the word precision.\n\
6409 You need not define this hook if @code{WORD_REGISTER_OPERATIONS} is not\n\
6410 defined to 1.",
6411 unsigned int, (void), default_min_arithmetic_precision)
6413 DEFHOOKPOD
6414 (atomic_test_and_set_trueval,
6415 "This value should be set if the result written by\
6416 @code{atomic_test_and_set} is not exactly 1, i.e. the\
6417 @code{bool} @code{true}.",
6418 unsigned char, 1)
6420 /* Return an unsigned int representing the alignment (in bits) of the atomic
6421 type which maps to machine MODE. This allows alignment to be overridden
6422 as needed. */
6423 DEFHOOK
6424 (atomic_align_for_mode,
6425 "If defined, this function returns an appropriate alignment in bits for an\
6426 atomic object of machine_mode @var{mode}. If 0 is returned then the\
6427 default alignment for the specified mode is used. ",
6428 unsigned int, (machine_mode mode),
6429 hook_uint_mode_0)
6431 DEFHOOK
6432 (atomic_assign_expand_fenv,
6433 "ISO C11 requires atomic compound assignments that may raise floating-point\
6434 exceptions to raise exceptions corresponding to the arithmetic operation\
6435 whose result was successfully stored in a compare-and-exchange sequence. \
6436 This requires code equivalent to calls to @code{feholdexcept},\
6437 @code{feclearexcept} and @code{feupdateenv} to be generated at\
6438 appropriate points in the compare-and-exchange sequence. This hook should\
6439 set @code{*@var{hold}} to an expression equivalent to the call to\
6440 @code{feholdexcept}, @code{*@var{clear}} to an expression equivalent to\
6441 the call to @code{feclearexcept} and @code{*@var{update}} to an expression\
6442 equivalent to the call to @code{feupdateenv}. The three expressions are\
6443 @code{NULL_TREE} on entry to the hook and may be left as @code{NULL_TREE}\
6444 if no code is required in a particular place. The default implementation\
6445 leaves all three expressions as @code{NULL_TREE}. The\
6446 @code{__atomic_feraiseexcept} function from @code{libatomic} may be of use\
6447 as part of the code generated in @code{*@var{update}}.",
6448 void, (tree *hold, tree *clear, tree *update),
6449 default_atomic_assign_expand_fenv)
6451 /* Leave the boolean fields at the end. */
6453 /* True if we can create zeroed data by switching to a BSS section
6454 and then using ASM_OUTPUT_SKIP to allocate the space. */
6455 DEFHOOKPOD
6456 (have_switchable_bss_sections,
6457 "This flag is true if we can create zeroed data by switching to a BSS\n\
6458 section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.\n\
6459 This is true on most ELF targets.",
6460 bool, false)
6462 /* True if "native" constructors and destructors are supported,
6463 false if we're using collect2 for the job. */
6464 DEFHOOKPOD
6465 (have_ctors_dtors,
6466 "This value is true if the target supports some ``native'' method of\n\
6467 collecting constructors and destructors to be run at startup and exit.\n\
6468 It is false if we must use @command{collect2}.",
6469 bool, false)
6471 /* True if thread-local storage is supported. */
6472 DEFHOOKPOD
6473 (have_tls,
6474 "Contains the value true if the target supports thread-local storage.\n\
6475 The default value is false.",
6476 bool, false)
6478 /* True if a small readonly data section is supported. */
6479 DEFHOOKPOD
6480 (have_srodata_section,
6481 "Contains the value true if the target places read-only\n\
6482 ``small data'' into a separate section. The default value is false.",
6483 bool, false)
6485 /* True if EH frame info sections should be zero-terminated. */
6486 DEFHOOKPOD
6487 (terminate_dw2_eh_frame_info,
6488 "Contains the value true if the target should add a zero word onto the\n\
6489 end of a Dwarf-2 frame info section when used for exception handling.\n\
6490 Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and\n\
6491 true otherwise.",
6492 bool, true)
6494 /* True if #NO_APP should be emitted at the beginning of assembly output. */
6495 DEFHOOKPOD
6496 (asm_file_start_app_off,
6497 "If this flag is true, the text of the macro @code{ASM_APP_OFF} will be\n\
6498 printed as the very first line in the assembly file, unless\n\
6499 @option{-fverbose-asm} is in effect. (If that macro has been defined\n\
6500 to the empty string, this variable has no effect.) With the normal\n\
6501 definition of @code{ASM_APP_OFF}, the effect is to notify the GNU\n\
6502 assembler that it need not bother stripping comments or extra\n\
6503 whitespace from its input. This allows it to work a bit faster.\n\
6505 The default is false. You should not set it to true unless you have\n\
6506 verified that your port does not generate any extra whitespace or\n\
6507 comments that will cause GAS to issue errors in NO_APP mode.",
6508 bool, false)
6510 /* True if output_file_directive should be called for main_input_filename
6511 at the beginning of assembly output. */
6512 DEFHOOKPOD
6513 (asm_file_start_file_directive,
6514 "If this flag is true, @code{output_file_directive} will be called\n\
6515 for the primary source file, immediately after printing\n\
6516 @code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect\n\
6517 this to be done. The default is false.",
6518 bool, false)
6520 /* Returns true if we should generate exception tables for use with the
6521 ARM EABI. The effects the encoding of function exception specifications. */
6522 DEFHOOKPOD
6523 (arm_eabi_unwinder,
6524 "This flag should be set to @code{true} on targets that use an ARM EABI\n\
6525 based unwinding library, and @code{false} on other targets. This effects\n\
6526 the format of unwinding tables, and how the unwinder in entered after\n\
6527 running a cleanup. The default is @code{false}.",
6528 bool, false)
6530 DEFHOOKPOD
6531 (want_debug_pub_sections,
6532 "True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\
6533 should be emitted. These sections are not used on most platforms, and\
6534 in particular GDB does not use them.",
6535 bool, false)
6537 DEFHOOKPOD
6538 (delay_sched2, "True if sched2 is not to be run at its normal place.\n\
6539 This usually means it will be run as part of machine-specific reorg.",
6540 bool, false)
6542 DEFHOOKPOD
6543 (delay_vartrack, "True if vartrack is not to be run at its normal place.\n\
6544 This usually means it will be run as part of machine-specific reorg.",
6545 bool, false)
6547 DEFHOOKPOD
6548 (no_register_allocation, "True if register allocation and the passes\n\
6549 following it should not be run. Usually true only for virtual assembler\n\
6550 targets.",
6551 bool, false)
6553 /* Leave the boolean fields at the end. */
6555 /* Functions related to mode switching. */
6556 #undef HOOK_PREFIX
6557 #define HOOK_PREFIX "TARGET_MODE_"
6558 HOOK_VECTOR (TARGET_TOGGLE_, mode_switching)
6560 DEFHOOK
6561 (emit,
6562 "Generate one or more insns to set @var{entity} to @var{mode}. @var{hard_reg_live} is the set of hard registers live at the point where the insn(s) are to be inserted. @var{prev_moxde} indicates the mode to switch from. Sets of a lower numbered entity will be emitted before sets of a higher numbered entity to a mode of the same or lower priority.",
6563 void, (int entity, int mode, int prev_mode, HARD_REG_SET regs_live), NULL)
6565 DEFHOOK
6566 (needed,
6567 "@var{entity} is an integer specifying a mode-switched entity. If @code{OPTIMIZE_MODE_SWITCHING} is defined, you must define this macro to return an integer value not larger than the corresponding element in @code{NUM_MODES_FOR_MODE_SWITCHING}, to denote the mode that @var{entity} must be switched into prior to the execution of @var{insn}.",
6568 int, (int entity, rtx_insn *insn), NULL)
6570 DEFHOOK
6571 (after,
6572 "@var{entity} is an integer specifying a mode-switched entity. If this macro is defined, it is evaluated for every @var{insn} during mode switching. It determines the mode that an insn results in (if different from the incoming mode).",
6573 int, (int entity, int mode, rtx_insn *insn), NULL)
6575 DEFHOOK
6576 (entry,
6577 "If this macro is defined, it is evaluated for every @var{entity} that needs mode switching. It should evaluate to an integer, which is a mode that @var{entity} is assumed to be switched to at function entry. If @code{TARGET_MODE_ENTRY} is defined then @code{TARGET_MODE_EXIT} must be defined.",
6578 int, (int entity), NULL)
6580 DEFHOOK
6581 (exit,
6582 "If this macro is defined, it is evaluated for every @var{entity} that needs mode switching. It should evaluate to an integer, which is a mode that @var{entity} is assumed to be switched to at function exit. If @code{TARGET_MODE_EXIT} is defined then @code{TARGET_MODE_ENTRY} must be defined.",
6583 int, (int entity), NULL)
6585 DEFHOOK
6586 (priority,
6587 "This macro specifies the order in which modes for @var{entity} are processed. 0 is the highest priority, @code{NUM_MODES_FOR_MODE_SWITCHING[@var{entity}] - 1} the lowest. The value of the macro should be an integer designating a mode for @var{entity}. For any fixed @var{entity}, @code{mode_priority} (@var{entity}, @var{n}) shall be a bijection in 0 @dots{} @code{num_modes_for_mode_switching[@var{entity}] - 1}.",
6588 int, (int entity, int n), NULL)
6590 HOOK_VECTOR_END (mode_switching)
6592 #undef HOOK_PREFIX
6593 #define HOOK_PREFIX "TARGET_"
6595 #define DEF_TARGET_INSN(NAME, PROTO) \
6596 DEFHOOK_UNDOC (have_##NAME, "", bool, (void), false)
6597 #include "target-insns.def"
6598 #undef DEF_TARGET_INSN
6600 #define DEF_TARGET_INSN(NAME, PROTO) \
6601 DEFHOOK_UNDOC (gen_##NAME, "", rtx_insn *, PROTO, NULL)
6602 #include "target-insns.def"
6603 #undef DEF_TARGET_INSN
6605 #define DEF_TARGET_INSN(NAME, PROTO) \
6606 DEFHOOKPOD (code_for_##NAME, "*", enum insn_code, CODE_FOR_nothing)
6607 #include "target-insns.def"
6608 #undef DEF_TARGET_INSN
6610 DEFHOOK
6611 (run_target_selftests,
6612 "If selftests are enabled, run any selftests for this target.",
6613 void, (void),
6614 NULL)
6616 /* Close the 'struct gcc_target' definition. */
6617 HOOK_VECTOR_END (C90_EMPTY_HACK)