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[official-gcc.git] / gcc / target.def
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1 /* Target hook definitions.
2 Copyright (C) 2001-2017 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 section for EXP. It may be a DECL or a constant. RELOC
511 is nonzero if runtime relocations must be applied; bit 1 will be
512 set if the runtime relocations require non-local name resolution.
513 ALIGN is the required alignment of the data. */
514 DEFHOOK
515 (select_section,
516 "Return the section into which @var{exp} should be placed. You can\n\
517 assume that @var{exp} is either a @code{VAR_DECL} node or a constant of\n\
518 some sort. @var{reloc} indicates whether the initial value of @var{exp}\n\
519 requires link-time relocations. Bit 0 is set when variable contains\n\
520 local relocations only, while bit 1 is set for global relocations.\n\
521 @var{align} is the constant alignment in bits.\n\
523 The default version of this function takes care of putting read-only\n\
524 variables in @code{readonly_data_section}.\n\
526 See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}.",
527 section *, (tree exp, int reloc, unsigned HOST_WIDE_INT align),
528 default_select_section)
530 /* Return a section for X. MODE is X's mode and ALIGN is its
531 alignment in bits. */
532 DEFHOOK
533 (select_rtx_section,
534 "Return the section into which a constant @var{x}, of mode @var{mode},\n\
535 should be placed. You can assume that @var{x} is some kind of\n\
536 constant in RTL@. The argument @var{mode} is redundant except in the\n\
537 case of a @code{const_int} rtx. @var{align} is the constant alignment\n\
538 in bits.\n\
540 The default version of this function takes care of putting symbolic\n\
541 constants in @code{flag_pic} mode in @code{data_section} and everything\n\
542 else in @code{readonly_data_section}.",
543 section *, (machine_mode mode, rtx x, unsigned HOST_WIDE_INT align),
544 default_select_rtx_section)
546 /* Select a unique section name for DECL. RELOC is the same as
547 for SELECT_SECTION. */
548 DEFHOOK
549 (unique_section,
550 "Build up a unique section name, expressed as a @code{STRING_CST} node,\n\
551 and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.\n\
552 As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether\n\
553 the initial value of @var{exp} requires link-time relocations.\n\
555 The default version of this function appends the symbol name to the\n\
556 ELF section name that would normally be used for the symbol. For\n\
557 example, the function @code{foo} would be placed in @code{.text.foo}.\n\
558 Whatever the actual target object format, this is often good enough.",
559 void, (tree decl, int reloc),
560 default_unique_section)
562 /* Return the readonly data section associated with function DECL. */
563 DEFHOOK
564 (function_rodata_section,
565 "Return the readonly data section associated with\n\
566 @samp{DECL_SECTION_NAME (@var{decl})}.\n\
567 The default version of this function selects @code{.gnu.linkonce.r.name} if\n\
568 the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name}\n\
569 if function is in @code{.text.name}, and the normal readonly-data section\n\
570 otherwise.",
571 section *, (tree decl),
572 default_function_rodata_section)
574 /* Nonnull if the target wants to override the default ".rodata" prefix
575 for mergeable data sections. */
576 DEFHOOKPOD
577 (mergeable_rodata_prefix,
578 "Usually, the compiler uses the prefix @code{\".rodata\"} to construct\n\
579 section names for mergeable constant data. Define this macro to override\n\
580 the string if a different section name should be used.",
581 const char *, ".rodata")
583 /* Return the section to be used for transactional memory clone tables. */
584 DEFHOOK
585 (tm_clone_table_section,
586 "Return the section that should be used for transactional memory clone\
587 tables.",
588 section *, (void), default_clone_table_section)
590 /* Output a constructor for a symbol with a given priority. */
591 DEFHOOK
592 (constructor,
593 "If defined, a function that outputs assembler code to arrange to call\n\
594 the function referenced by @var{symbol} at initialization time.\n\
596 Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking\n\
597 no arguments and with no return value. If the target supports initialization\n\
598 priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY};\n\
599 otherwise it must be @code{DEFAULT_INIT_PRIORITY}.\n\
601 If this macro is not defined by the target, a suitable default will\n\
602 be chosen if (1) the target supports arbitrary section names, (2) the\n\
603 target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2}\n\
604 is not defined.",
605 void, (rtx symbol, int priority), NULL)
607 /* Output a destructor for a symbol with a given priority. */
608 DEFHOOK
609 (destructor,
610 "This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination\n\
611 functions rather than initialization functions.",
612 void, (rtx symbol, int priority), NULL)
614 /* Output the assembler code for a thunk function. THUNK_DECL is the
615 declaration for the thunk function itself, FUNCTION is the decl for
616 the target function. DELTA is an immediate constant offset to be
617 added to THIS. If VCALL_OFFSET is nonzero, the word at
618 *(*this + vcall_offset) should be added to THIS. */
619 DEFHOOK
620 (output_mi_thunk,
621 "A function that outputs the assembler code for a thunk\n\
622 function, used to implement C++ virtual function calls with multiple\n\
623 inheritance. The thunk acts as a wrapper around a virtual function,\n\
624 adjusting the implicit object parameter before handing control off to\n\
625 the real function.\n\
627 First, emit code to add the integer @var{delta} to the location that\n\
628 contains the incoming first argument. Assume that this argument\n\
629 contains a pointer, and is the one used to pass the @code{this} pointer\n\
630 in C++. This is the incoming argument @emph{before} the function prologue,\n\
631 e.g.@: @samp{%o0} on a sparc. The addition must preserve the values of\n\
632 all other incoming arguments.\n\
634 Then, if @var{vcall_offset} is nonzero, an additional adjustment should be\n\
635 made after adding @code{delta}. In particular, if @var{p} is the\n\
636 adjusted pointer, the following adjustment should be made:\n\
638 @smallexample\n\
639 p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]\n\
640 @end smallexample\n\
642 After the additions, emit code to jump to @var{function}, which is a\n\
643 @code{FUNCTION_DECL}. This is a direct pure jump, not a call, and does\n\
644 not touch the return address. Hence returning from @var{FUNCTION} will\n\
645 return to whoever called the current @samp{thunk}.\n\
647 The effect must be as if @var{function} had been called directly with\n\
648 the adjusted first argument. This macro is responsible for emitting all\n\
649 of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE}\n\
650 and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked.\n\
652 The @var{thunk_fndecl} is redundant. (@var{delta} and @var{function}\n\
653 have already been extracted from it.) It might possibly be useful on\n\
654 some targets, but probably not.\n\
656 If you do not define this macro, the target-independent code in the C++\n\
657 front end will generate a less efficient heavyweight thunk that calls\n\
658 @var{function} instead of jumping to it. The generic approach does\n\
659 not support varargs.",
660 void, (FILE *file, tree thunk_fndecl, HOST_WIDE_INT delta,
661 HOST_WIDE_INT vcall_offset, tree function),
662 NULL)
664 /* Determine whether output_mi_thunk would succeed. */
665 /* ??? Ideally, this hook would not exist, and success or failure
666 would be returned from output_mi_thunk directly. But there's
667 too much undo-able setup involved in invoking output_mi_thunk.
668 Could be fixed by making output_mi_thunk emit rtl instead of
669 text to the output file. */
670 DEFHOOK
671 (can_output_mi_thunk,
672 "A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able\n\
673 to output the assembler code for the thunk function specified by the\n\
674 arguments it is passed, and false otherwise. In the latter case, the\n\
675 generic approach will be used by the C++ front end, with the limitations\n\
676 previously exposed.",
677 bool, (const_tree thunk_fndecl, HOST_WIDE_INT delta,
678 HOST_WIDE_INT vcall_offset, const_tree function),
679 hook_bool_const_tree_hwi_hwi_const_tree_false)
681 /* Output any boilerplate text needed at the beginning of a
682 translation unit. */
683 DEFHOOK
684 (file_start,
685 "Output to @code{asm_out_file} any text which the assembler expects to\n\
686 find at the beginning of a file. The default behavior is controlled\n\
687 by two flags, documented below. Unless your target's assembler is\n\
688 quite unusual, if you override the default, you should call\n\
689 @code{default_file_start} at some point in your target hook. This\n\
690 lets other target files rely on these variables.",
691 void, (void),
692 default_file_start)
694 /* Output any boilerplate text needed at the end of a translation unit. */
695 DEFHOOK
696 (file_end,
697 "Output to @code{asm_out_file} any text which the assembler expects\n\
698 to find at the end of a file. The default is to output nothing.",
699 void, (void),
700 hook_void_void)
702 /* Output any boilerplate text needed at the beginning of an
703 LTO output stream. */
704 DEFHOOK
705 (lto_start,
706 "Output to @code{asm_out_file} any text which the assembler expects\n\
707 to find at the start of an LTO section. The default is to output\n\
708 nothing.",
709 void, (void),
710 hook_void_void)
712 /* Output any boilerplate text needed at the end of an
713 LTO output stream. */
714 DEFHOOK
715 (lto_end,
716 "Output to @code{asm_out_file} any text which the assembler expects\n\
717 to find at the end of an LTO section. The default is to output\n\
718 nothing.",
719 void, (void),
720 hook_void_void)
722 /* Output any boilerplace text needed at the end of a
723 translation unit before debug and unwind info is emitted. */
724 DEFHOOK
725 (code_end,
726 "Output to @code{asm_out_file} any text which is needed before emitting\n\
727 unwind info and debug info at the end of a file. Some targets emit\n\
728 here PIC setup thunks that cannot be emitted at the end of file,\n\
729 because they couldn't have unwind info then. The default is to output\n\
730 nothing.",
731 void, (void),
732 hook_void_void)
734 /* Output an assembler pseudo-op to declare a library function name
735 external. */
736 DEFHOOK
737 (external_libcall,
738 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
739 pseudo-op to declare a library function name external. The name of the\n\
740 library function is given by @var{symref}, which is a @code{symbol_ref}.",
741 void, (rtx symref),
742 default_external_libcall)
744 /* Output an assembler directive to mark decl live. This instructs
745 linker to not dead code strip this symbol. */
746 DEFHOOK
747 (mark_decl_preserved,
748 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
749 directive to annotate @var{symbol} as used. The Darwin target uses the\n\
750 .no_dead_code_strip directive.",
751 void, (const char *symbol),
752 hook_void_constcharptr)
754 /* Output a record of the command line switches that have been passed. */
755 DEFHOOK
756 (record_gcc_switches,
757 "Provides the target with the ability to record the gcc command line\n\
758 switches that have been passed to the compiler, and options that are\n\
759 enabled. The @var{type} argument specifies what is being recorded.\n\
760 It can take the following values:\n\
762 @table @gcctabopt\n\
763 @item SWITCH_TYPE_PASSED\n\
764 @var{text} is a command line switch that has been set by the user.\n\
766 @item SWITCH_TYPE_ENABLED\n\
767 @var{text} is an option which has been enabled. This might be as a\n\
768 direct result of a command line switch, or because it is enabled by\n\
769 default or because it has been enabled as a side effect of a different\n\
770 command line switch. For example, the @option{-O2} switch enables\n\
771 various different individual optimization passes.\n\
773 @item SWITCH_TYPE_DESCRIPTIVE\n\
774 @var{text} is either NULL or some descriptive text which should be\n\
775 ignored. If @var{text} is NULL then it is being used to warn the\n\
776 target hook that either recording is starting or ending. The first\n\
777 time @var{type} is SWITCH_TYPE_DESCRIPTIVE and @var{text} is NULL, the\n\
778 warning is for start up and the second time the warning is for\n\
779 wind down. This feature is to allow the target hook to make any\n\
780 necessary preparations before it starts to record switches and to\n\
781 perform any necessary tidying up after it has finished recording\n\
782 switches.\n\
784 @item SWITCH_TYPE_LINE_START\n\
785 This option can be ignored by this target hook.\n\
787 @item SWITCH_TYPE_LINE_END\n\
788 This option can be ignored by this target hook.\n\
789 @end table\n\
791 The hook's return value must be zero. Other return values may be\n\
792 supported in the future.\n\
794 By default this hook is set to NULL, but an example implementation is\n\
795 provided for ELF based targets. Called @var{elf_record_gcc_switches},\n\
796 it records the switches as ASCII text inside a new, string mergeable\n\
797 section in the assembler output file. The name of the new section is\n\
798 provided by the @code{TARGET_ASM_RECORD_GCC_SWITCHES_SECTION} target\n\
799 hook.",
800 int, (print_switch_type type, const char *text),
801 NULL)
803 /* The name of the section that the example ELF implementation of
804 record_gcc_switches will use to store the information. Target
805 specific versions of record_gcc_switches may or may not use
806 this information. */
807 DEFHOOKPOD
808 (record_gcc_switches_section,
809 "This is the name of the section that will be created by the example\n\
810 ELF implementation of the @code{TARGET_ASM_RECORD_GCC_SWITCHES} target\n\
811 hook.",
812 const char *, ".GCC.command.line")
814 /* Output the definition of a section anchor. */
815 DEFHOOK
816 (output_anchor,
817 "Write the assembly code to define section anchor @var{x}, which is a\n\
818 @code{SYMBOL_REF} for which @samp{SYMBOL_REF_ANCHOR_P (@var{x})} is true.\n\
819 The hook is called with the assembly output position set to the beginning\n\
820 of @code{SYMBOL_REF_BLOCK (@var{x})}.\n\
822 If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses\n\
823 it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}.\n\
824 If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition\n\
825 is @code{NULL}, which disables the use of section anchors altogether.",
826 void, (rtx x),
827 default_asm_output_anchor)
829 DEFHOOK
830 (output_ident,
831 "Output a string based on @var{name}, suitable for the @samp{#ident} \
832 directive, or the equivalent directive or pragma in non-C-family languages. \
833 If this hook is not defined, nothing is output for the @samp{#ident} \
834 directive.",
835 void, (const char *name),
836 hook_void_constcharptr)
838 /* Output a DTP-relative reference to a TLS symbol. */
839 DEFHOOK
840 (output_dwarf_dtprel,
841 "If defined, this target hook is a function which outputs a DTP-relative\n\
842 reference to the given TLS symbol of the specified size.",
843 void, (FILE *file, int size, rtx x),
844 NULL)
846 /* Some target machines need to postscan each insn after it is output. */
847 DEFHOOK
848 (final_postscan_insn,
849 "If defined, this target hook is a function which is executed just after the\n\
850 output of assembler code for @var{insn}, to change the mode of the assembler\n\
851 if necessary.\n\
853 Here the argument @var{opvec} is the vector containing the operands\n\
854 extracted from @var{insn}, and @var{noperands} is the number of\n\
855 elements of the vector which contain meaningful data for this insn.\n\
856 The contents of this vector are what was used to convert the insn\n\
857 template into assembler code, so you can change the assembler mode\n\
858 by checking the contents of the vector.",
859 void, (FILE *file, rtx_insn *insn, rtx *opvec, int noperands),
860 NULL)
862 /* Emit the trampoline template. This hook may be NULL. */
863 DEFHOOK
864 (trampoline_template,
865 "This hook is called by @code{assemble_trampoline_template} to output,\n\
866 on the stream @var{f}, assembler code for a block of data that contains\n\
867 the constant parts of a trampoline. This code should not include a\n\
868 label---the label is taken care of automatically.\n\
870 If you do not define this hook, it means no template is needed\n\
871 for the target. Do not define this hook on systems where the block move\n\
872 code to copy the trampoline into place would be larger than the code\n\
873 to generate it on the spot.",
874 void, (FILE *f),
875 NULL)
877 DEFHOOK
878 (output_source_filename,
879 "Output DWARF debugging information which indicates that filename\
880 @var{name} is the current source file to the stdio stream @var{file}.\n\
882 This target hook need not be defined if the standard form of output\
883 for the file format in use is appropriate.",
884 void ,(FILE *file, const char *name),
885 default_asm_output_source_filename)
887 DEFHOOK
888 (output_addr_const_extra,
889 "A target hook to recognize @var{rtx} patterns that @code{output_addr_const}\n\
890 can't deal with, and output assembly code to @var{file} corresponding to\n\
891 the pattern @var{x}. This may be used to allow machine-dependent\n\
892 @code{UNSPEC}s to appear within constants.\n\
894 If target hook fails to recognize a pattern, it must return @code{false},\n\
895 so that a standard error message is printed. If it prints an error message\n\
896 itself, by calling, for example, @code{output_operand_lossage}, it may just\n\
897 return @code{true}.",
898 bool, (FILE *file, rtx x),
899 hook_bool_FILEptr_rtx_false)
901 /* ??? The TARGET_PRINT_OPERAND* hooks are part of the asm_out struct,
902 even though that is not reflected in the macro name to override their
903 initializers. */
904 #undef HOOK_PREFIX
905 #define HOOK_PREFIX "TARGET_"
907 /* Emit a machine-specific insn operand. */
908 /* ??? tm.texi only documents the old macro PRINT_OPERAND,
909 not this hook, and uses a different name for the argument FILE. */
910 DEFHOOK_UNDOC
911 (print_operand,
913 void, (FILE *file, rtx x, int code),
914 default_print_operand)
916 /* Emit a machine-specific memory address. */
917 /* ??? tm.texi only documents the old macro PRINT_OPERAND_ADDRESS,
918 not this hook, and uses different argument names. */
919 DEFHOOK_UNDOC
920 (print_operand_address,
922 void, (FILE *file, machine_mode mode, rtx addr),
923 default_print_operand_address)
925 /* Determine whether CODE is a valid punctuation character for the
926 `print_operand' hook. */
927 /* ??? tm.texi only documents the old macro PRINT_OPERAND_PUNCT_VALID_P,
928 not this hook. */
929 DEFHOOK_UNDOC
930 (print_operand_punct_valid_p,
932 bool ,(unsigned char code),
933 default_print_operand_punct_valid_p)
935 /* Given a symbol name, perform same mangling as assemble_name and
936 ASM_OUTPUT_LABELREF, returning result as an IDENTIFIER_NODE. */
937 DEFHOOK
938 (mangle_assembler_name,
939 "Given a symbol @var{name}, perform same mangling as @code{varasm.c}'s\
940 @code{assemble_name}, but in memory rather than to a file stream, returning\
941 result as an @code{IDENTIFIER_NODE}. Required for correct LTO symtabs. The\
942 default implementation calls the @code{TARGET_STRIP_NAME_ENCODING} hook and\
943 then prepends the @code{USER_LABEL_PREFIX}, if any.",
944 tree, (const char *name),
945 default_mangle_assembler_name)
947 HOOK_VECTOR_END (asm_out)
949 /* Functions relating to instruction scheduling. All of these
950 default to null pointers, which haifa-sched.c looks for and handles. */
951 #undef HOOK_PREFIX
952 #define HOOK_PREFIX "TARGET_SCHED_"
953 HOOK_VECTOR (TARGET_SCHED, sched)
955 /* Given the current cost, COST, of an insn, INSN, calculate and
956 return a new cost based on its relationship to DEP_INSN through
957 the dependence LINK. The default is to make no adjustment. */
958 DEFHOOK
959 (adjust_cost,
960 "This function corrects the value of @var{cost} based on the\n\
961 relationship between @var{insn} and @var{dep_insn} through a\n\
962 dependence of type dep_type, and strength @var{dw}. It should return the new\n\
963 value. The default is to make no adjustment to @var{cost}. This can be\n\
964 used for example to specify to the scheduler using the traditional pipeline\n\
965 description that an output- or anti-dependence does not incur the same cost\n\
966 as a data-dependence. If the scheduler using the automaton based pipeline\n\
967 description, the cost of anti-dependence is zero and the cost of\n\
968 output-dependence is maximum of one and the difference of latency\n\
969 times of the first and the second insns. If these values are not\n\
970 acceptable, you could use the hook to modify them too. See also\n\
971 @pxref{Processor pipeline description}.",
972 int, (rtx_insn *insn, int dep_type1, rtx_insn *dep_insn, int cost,
973 unsigned int dw),
974 NULL)
976 /* Adjust the priority of an insn as you see fit. Returns the new priority. */
977 DEFHOOK
978 (adjust_priority,
979 "This hook adjusts the integer scheduling priority @var{priority} of\n\
980 @var{insn}. It should return the new priority. Increase the priority to\n\
981 execute @var{insn} earlier, reduce the priority to execute @var{insn}\n\
982 later. Do not define this hook if you do not need to adjust the\n\
983 scheduling priorities of insns.",
984 int, (rtx_insn *insn, int priority), NULL)
986 /* Function which returns the maximum number of insns that can be
987 scheduled in the same machine cycle. This must be constant
988 over an entire compilation. The default is 1. */
989 DEFHOOK
990 (issue_rate,
991 "This hook returns the maximum number of instructions that can ever\n\
992 issue at the same time on the target machine. The default is one.\n\
993 Although the insn scheduler can define itself the possibility of issue\n\
994 an insn on the same cycle, the value can serve as an additional\n\
995 constraint to issue insns on the same simulated processor cycle (see\n\
996 hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).\n\
997 This value must be constant over the entire compilation. If you need\n\
998 it to vary depending on what the instructions are, you must use\n\
999 @samp{TARGET_SCHED_VARIABLE_ISSUE}.",
1000 int, (void), NULL)
1002 /* Calculate how much this insn affects how many more insns we
1003 can emit this cycle. Default is they all cost the same. */
1004 DEFHOOK
1005 (variable_issue,
1006 "This hook is executed by the scheduler after it has scheduled an insn\n\
1007 from the ready list. It should return the number of insns which can\n\
1008 still be issued in the current cycle. The default is\n\
1009 @samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and\n\
1010 @code{USE}, which normally are not counted against the issue rate.\n\
1011 You should define this hook if some insns take more machine resources\n\
1012 than others, so that fewer insns can follow them in the same cycle.\n\
1013 @var{file} is either a null pointer, or a stdio stream to write any\n\
1014 debug output to. @var{verbose} is the verbose level provided by\n\
1015 @option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that\n\
1016 was scheduled.",
1017 int, (FILE *file, int verbose, rtx_insn *insn, int more), NULL)
1019 /* Initialize machine-dependent scheduling code. */
1020 DEFHOOK
1021 (init,
1022 "This hook is executed by the scheduler at the beginning of each block of\n\
1023 instructions that are to be scheduled. @var{file} is either a null\n\
1024 pointer, or a stdio stream to write any debug output to. @var{verbose}\n\
1025 is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1026 @var{max_ready} is the maximum number of insns in the current scheduling\n\
1027 region that can be live at the same time. This can be used to allocate\n\
1028 scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}.",
1029 void, (FILE *file, int verbose, int max_ready), NULL)
1031 /* Finalize machine-dependent scheduling code. */
1032 DEFHOOK
1033 (finish,
1034 "This hook is executed by the scheduler at the end of each block of\n\
1035 instructions that are to be scheduled. It can be used to perform\n\
1036 cleanup of any actions done by the other scheduling hooks. @var{file}\n\
1037 is either a null pointer, or a stdio stream to write any debug output\n\
1038 to. @var{verbose} is the verbose level provided by\n\
1039 @option{-fsched-verbose-@var{n}}.",
1040 void, (FILE *file, int verbose), NULL)
1042 /* Initialize machine-dependent function wide scheduling code. */
1043 DEFHOOK
1044 (init_global,
1045 "This hook is executed by the scheduler after function level initializations.\n\
1046 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1047 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1048 @var{old_max_uid} is the maximum insn uid when scheduling begins.",
1049 void, (FILE *file, int verbose, int old_max_uid), NULL)
1051 /* Finalize machine-dependent function wide scheduling code. */
1052 DEFHOOK
1053 (finish_global,
1054 "This is the cleanup hook corresponding to @code{TARGET_SCHED_INIT_GLOBAL}.\n\
1055 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1056 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.",
1057 void, (FILE *file, int verbose), NULL)
1059 /* Reorder insns in a machine-dependent fashion, in two different
1060 places. Default does nothing. */
1061 DEFHOOK
1062 (reorder,
1063 "This hook is executed by the scheduler after it has scheduled the ready\n\
1064 list, to allow the machine description to reorder it (for example to\n\
1065 combine two small instructions together on @samp{VLIW} machines).\n\
1066 @var{file} is either a null pointer, or a stdio stream to write any\n\
1067 debug output to. @var{verbose} is the verbose level provided by\n\
1068 @option{-fsched-verbose-@var{n}}. @var{ready} is a pointer to the ready\n\
1069 list of instructions that are ready to be scheduled. @var{n_readyp} is\n\
1070 a pointer to the number of elements in the ready list. The scheduler\n\
1071 reads the ready list in reverse order, starting with\n\
1072 @var{ready}[@var{*n_readyp} @minus{} 1] and going to @var{ready}[0]. @var{clock}\n\
1073 is the timer tick of the scheduler. You may modify the ready list and\n\
1074 the number of ready insns. The return value is the number of insns that\n\
1075 can issue this cycle; normally this is just @code{issue_rate}. See also\n\
1076 @samp{TARGET_SCHED_REORDER2}.",
1077 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1079 DEFHOOK
1080 (reorder2,
1081 "Like @samp{TARGET_SCHED_REORDER}, but called at a different time. That\n\
1082 function is called whenever the scheduler starts a new cycle. This one\n\
1083 is called once per iteration over a cycle, immediately after\n\
1084 @samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and\n\
1085 return the number of insns to be scheduled in the same cycle. Defining\n\
1086 this hook can be useful if there are frequent situations where\n\
1087 scheduling one insn causes other insns to become ready in the same\n\
1088 cycle. These other insns can then be taken into account properly.",
1089 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1091 DEFHOOK
1092 (macro_fusion_p,
1093 "This hook is used to check whether target platform supports macro fusion.",
1094 bool, (void), NULL)
1096 DEFHOOK
1097 (macro_fusion_pair_p,
1098 "This hook is used to check whether two insns should be macro fused for\n\
1099 a target microarchitecture. If this hook returns true for the given insn pair\n\
1100 (@var{prev} and @var{curr}), the scheduler will put them into a sched\n\
1101 group, and they will not be scheduled apart. The two insns will be either\n\
1102 two SET insns or a compare and a conditional jump and this hook should\n\
1103 validate any dependencies needed to fuse the two insns together.",
1104 bool, (rtx_insn *prev, rtx_insn *curr), NULL)
1106 /* The following member value is a pointer to a function called
1107 after evaluation forward dependencies of insns in chain given
1108 by two parameter values (head and tail correspondingly). */
1109 DEFHOOK
1110 (dependencies_evaluation_hook,
1111 "This hook is called after evaluation forward dependencies of insns in\n\
1112 chain given by two parameter values (@var{head} and @var{tail}\n\
1113 correspondingly) but before insns scheduling of the insn chain. For\n\
1114 example, it can be used for better insn classification if it requires\n\
1115 analysis of dependencies. This hook can use backward and forward\n\
1116 dependencies of the insn scheduler because they are already\n\
1117 calculated.",
1118 void, (rtx_insn *head, rtx_insn *tail), NULL)
1120 /* The values of the following four members are pointers to functions
1121 used to simplify the automaton descriptions. dfa_pre_cycle_insn and
1122 dfa_post_cycle_insn give functions returning insns which are used to
1123 change the pipeline hazard recognizer state when the new simulated
1124 processor cycle correspondingly starts and finishes. The function
1125 defined by init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are
1126 used to initialize the corresponding insns. The default values of
1127 the members result in not changing the automaton state when the
1128 new simulated processor cycle correspondingly starts and finishes. */
1130 DEFHOOK
1131 (init_dfa_pre_cycle_insn,
1132 "The hook can be used to initialize data used by the previous hook.",
1133 void, (void), NULL)
1135 DEFHOOK
1136 (dfa_pre_cycle_insn,
1137 "The hook returns an RTL insn. The automaton state used in the\n\
1138 pipeline hazard recognizer is changed as if the insn were scheduled\n\
1139 when the new simulated processor cycle starts. Usage of the hook may\n\
1140 simplify the automaton pipeline description for some @acronym{VLIW}\n\
1141 processors. If the hook is defined, it is used only for the automaton\n\
1142 based pipeline description. The default is not to change the state\n\
1143 when the new simulated processor cycle starts.",
1144 rtx, (void), NULL)
1146 DEFHOOK
1147 (init_dfa_post_cycle_insn,
1148 "The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but\n\
1149 used to initialize data used by the previous hook.",
1150 void, (void), NULL)
1152 DEFHOOK
1153 (dfa_post_cycle_insn,
1154 "The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1155 to changed the state as if the insn were scheduled when the new\n\
1156 simulated processor cycle finishes.",
1157 rtx_insn *, (void), NULL)
1159 /* The values of the following two members are pointers to
1160 functions used to simplify the automaton descriptions.
1161 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
1162 immediately before and after cycle is advanced. */
1164 DEFHOOK
1165 (dfa_pre_advance_cycle,
1166 "The hook to notify target that the current simulated cycle is about to finish.\n\
1167 The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1168 to change the state in more complicated situations - e.g., when advancing\n\
1169 state on a single insn is not enough.",
1170 void, (void), NULL)
1172 DEFHOOK
1173 (dfa_post_advance_cycle,
1174 "The hook to notify target that new simulated cycle has just started.\n\
1175 The hook is analogous to @samp{TARGET_SCHED_DFA_POST_CYCLE_INSN} but used\n\
1176 to change the state in more complicated situations - e.g., when advancing\n\
1177 state on a single insn is not enough.",
1178 void, (void), NULL)
1180 /* The following member value is a pointer to a function returning value
1181 which defines how many insns in queue `ready' will we try for
1182 multi-pass scheduling. If the member value is nonzero and the
1183 function returns positive value, the DFA based scheduler will make
1184 multi-pass scheduling for the first cycle. In other words, we will
1185 try to choose ready insn which permits to start maximum number of
1186 insns on the same cycle. */
1187 DEFHOOK
1188 (first_cycle_multipass_dfa_lookahead,
1189 "This hook controls better choosing an insn from the ready insn queue\n\
1190 for the @acronym{DFA}-based insn scheduler. Usually the scheduler\n\
1191 chooses the first insn from the queue. If the hook returns a positive\n\
1192 value, an additional scheduler code tries all permutations of\n\
1193 @samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}\n\
1194 subsequent ready insns to choose an insn whose issue will result in\n\
1195 maximal number of issued insns on the same cycle. For the\n\
1196 @acronym{VLIW} processor, the code could actually solve the problem of\n\
1197 packing simple insns into the @acronym{VLIW} insn. Of course, if the\n\
1198 rules of @acronym{VLIW} packing are described in the automaton.\n\
1200 This code also could be used for superscalar @acronym{RISC}\n\
1201 processors. Let us consider a superscalar @acronym{RISC} processor\n\
1202 with 3 pipelines. Some insns can be executed in pipelines @var{A} or\n\
1203 @var{B}, some insns can be executed only in pipelines @var{B} or\n\
1204 @var{C}, and one insn can be executed in pipeline @var{B}. The\n\
1205 processor may issue the 1st insn into @var{A} and the 2nd one into\n\
1206 @var{B}. In this case, the 3rd insn will wait for freeing @var{B}\n\
1207 until the next cycle. If the scheduler issues the 3rd insn the first,\n\
1208 the processor could issue all 3 insns per cycle.\n\
1210 Actually this code demonstrates advantages of the automaton based\n\
1211 pipeline hazard recognizer. We try quickly and easy many insn\n\
1212 schedules to choose the best one.\n\
1214 The default is no multipass scheduling.",
1215 int, (void), NULL)
1217 /* The following member value is pointer to a function controlling
1218 what insns from the ready insn queue will be considered for the
1219 multipass insn scheduling. If the hook returns zero for insn
1220 passed as the parameter, the insn will be not chosen to be issued. */
1221 DEFHOOK
1222 (first_cycle_multipass_dfa_lookahead_guard,
1223 "\n\
1224 This hook controls what insns from the ready insn queue will be\n\
1225 considered for the multipass insn scheduling. If the hook returns\n\
1226 zero for @var{insn}, the insn will be considered in multipass scheduling.\n\
1227 Positive return values will remove @var{insn} from consideration on\n\
1228 the current round of multipass scheduling.\n\
1229 Negative return values will remove @var{insn} from consideration for given\n\
1230 number of cycles.\n\
1231 Backends should be careful about returning non-zero for highest priority\n\
1232 instruction at position 0 in the ready list. @var{ready_index} is passed\n\
1233 to allow backends make correct judgements.\n\
1235 The default is that any ready insns can be chosen to be issued.",
1236 int, (rtx_insn *insn, int ready_index), NULL)
1238 /* This hook prepares the target for a new round of multipass
1239 scheduling.
1240 DATA is a pointer to target-specific data used for multipass scheduling.
1241 READY_TRY and N_READY represent the current state of search in the
1242 optimization space. The target can filter out instructions that
1243 should not be tried during current round by setting corresponding
1244 elements in READY_TRY to non-zero.
1245 FIRST_CYCLE_INSN_P is true if this is the first round of multipass
1246 scheduling on current cycle. */
1247 DEFHOOK
1248 (first_cycle_multipass_begin,
1249 "This hook prepares the target backend for a new round of multipass\n\
1250 scheduling.",
1251 void, (void *data, signed char *ready_try, int n_ready, bool first_cycle_insn_p),
1252 NULL)
1254 /* This hook is called when multipass scheduling evaluates instruction INSN.
1255 DATA is a pointer to target-specific data that can be used to record effects
1256 of INSN on CPU that are not described in DFA.
1257 READY_TRY and N_READY represent the current state of search in the
1258 optimization space. The target can filter out instructions that
1259 should not be tried after issuing INSN by setting corresponding
1260 elements in READY_TRY to non-zero.
1261 INSN is the instruction being evaluated.
1262 PREV_DATA is a pointer to target-specific data corresponding
1263 to a state before issuing INSN. */
1264 DEFHOOK
1265 (first_cycle_multipass_issue,
1266 "This hook is called when multipass scheduling evaluates instruction INSN.",
1267 void, (void *data, signed char *ready_try, int n_ready, rtx_insn *insn,
1268 const void *prev_data), NULL)
1270 /* This hook is called when multipass scheduling backtracks from evaluation of
1271 instruction corresponding to DATA.
1272 DATA is a pointer to target-specific data that stores the effects
1273 of instruction from which the algorithm backtracks on CPU that are not
1274 described in DFA.
1275 READY_TRY and N_READY represent the current state of search in the
1276 optimization space. The target can filter out instructions that
1277 should not be tried after issuing INSN by setting corresponding
1278 elements in READY_TRY to non-zero. */
1279 DEFHOOK
1280 (first_cycle_multipass_backtrack,
1281 "This is called when multipass scheduling backtracks from evaluation of\n\
1282 an instruction.",
1283 void, (const void *data, signed char *ready_try, int n_ready), NULL)
1285 /* This hook notifies the target about the result of the concluded current
1286 round of multipass scheduling.
1287 DATA is a pointer.
1288 If DATA is non-NULL it points to target-specific data used for multipass
1289 scheduling which corresponds to instruction at the start of the chain of
1290 the winning solution. DATA is NULL when multipass scheduling cannot find
1291 a good enough solution on current cycle and decides to retry later,
1292 usually after advancing the cycle count. */
1293 DEFHOOK
1294 (first_cycle_multipass_end,
1295 "This hook notifies the target about the result of the concluded current\n\
1296 round of multipass scheduling.",
1297 void, (const void *data), NULL)
1299 /* This hook is called to initialize target-specific data for multipass
1300 scheduling after it has been allocated.
1301 DATA is a pointer to target-specific data that stores the effects
1302 of instruction from which the algorithm backtracks on CPU that are not
1303 described in DFA. */
1304 DEFHOOK
1305 (first_cycle_multipass_init,
1306 "This hook initializes target-specific data used in multipass scheduling.",
1307 void, (void *data), NULL)
1309 /* This hook is called to finalize target-specific data for multipass
1310 scheduling before it is deallocated.
1311 DATA is a pointer to target-specific data that stores the effects
1312 of instruction from which the algorithm backtracks on CPU that are not
1313 described in DFA. */
1314 DEFHOOK
1315 (first_cycle_multipass_fini,
1316 "This hook finalizes target-specific data used in multipass scheduling.",
1317 void, (void *data), NULL)
1319 /* The following member value is pointer to a function called by
1320 the insn scheduler before issuing insn passed as the third
1321 parameter on given cycle. If the hook returns nonzero, the
1322 insn is not issued on given processors cycle. Instead of that,
1323 the processor cycle is advanced. If the value passed through
1324 the last parameter is zero, the insn ready queue is not sorted
1325 on the new cycle start as usually. The first parameter passes
1326 file for debugging output. The second one passes the scheduler
1327 verbose level of the debugging output. The forth and the fifth
1328 parameter values are correspondingly processor cycle on which
1329 the previous insn has been issued and the current processor cycle. */
1330 DEFHOOK
1331 (dfa_new_cycle,
1332 "This hook is called by the insn scheduler before issuing @var{insn}\n\
1333 on cycle @var{clock}. If the hook returns nonzero,\n\
1334 @var{insn} is not issued on this processor cycle. Instead,\n\
1335 the processor cycle is advanced. If *@var{sort_p}\n\
1336 is zero, the insn ready queue is not sorted on the new cycle\n\
1337 start as usually. @var{dump} and @var{verbose} specify the file and\n\
1338 verbosity level to use for debugging output.\n\
1339 @var{last_clock} and @var{clock} are, respectively, the\n\
1340 processor cycle on which the previous insn has been issued,\n\
1341 and the current processor cycle.",
1342 int, (FILE *dump, int verbose, rtx_insn *insn, int last_clock,
1343 int clock, int *sort_p),
1344 NULL)
1346 /* The following member value is a pointer to a function called by the
1347 insn scheduler. It should return true if there exists a dependence
1348 which is considered costly by the target, between the insn
1349 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
1350 the dep that represents the dependence between the two insns. The
1351 second argument is the cost of the dependence as estimated by
1352 the scheduler. The last argument is the distance in cycles
1353 between the already scheduled insn (first parameter) and the
1354 second insn (second parameter). */
1355 DEFHOOK
1356 (is_costly_dependence,
1357 "This hook is used to define which dependences are considered costly by\n\
1358 the target, so costly that it is not advisable to schedule the insns that\n\
1359 are involved in the dependence too close to one another. The parameters\n\
1360 to this hook are as follows: The first parameter @var{_dep} is the dependence\n\
1361 being evaluated. The second parameter @var{cost} is the cost of the\n\
1362 dependence as estimated by the scheduler, and the third\n\
1363 parameter @var{distance} is the distance in cycles between the two insns.\n\
1364 The hook returns @code{true} if considering the distance between the two\n\
1365 insns the dependence between them is considered costly by the target,\n\
1366 and @code{false} otherwise.\n\
1368 Defining this hook can be useful in multiple-issue out-of-order machines,\n\
1369 where (a) it's practically hopeless to predict the actual data/resource\n\
1370 delays, however: (b) there's a better chance to predict the actual grouping\n\
1371 that will be formed, and (c) correctly emulating the grouping can be very\n\
1372 important. In such targets one may want to allow issuing dependent insns\n\
1373 closer to one another---i.e., closer than the dependence distance; however,\n\
1374 not in cases of ``costly dependences'', which this hooks allows to define.",
1375 bool, (struct _dep *_dep, int cost, int distance), NULL)
1377 /* The following member value is a pointer to a function called
1378 by the insn scheduler. This hook is called to notify the backend
1379 that new instructions were emitted. */
1380 DEFHOOK
1381 (h_i_d_extended,
1382 "This hook is called by the insn scheduler after emitting a new instruction to\n\
1383 the instruction stream. The hook notifies a target backend to extend its\n\
1384 per instruction data structures.",
1385 void, (void), NULL)
1387 /* Next 5 functions are for multi-point scheduling. */
1389 /* Allocate memory for scheduler context. */
1390 DEFHOOK
1391 (alloc_sched_context,
1392 "Return a pointer to a store large enough to hold target scheduling context.",
1393 void *, (void), NULL)
1395 /* Fills the context from the local machine scheduler context. */
1396 DEFHOOK
1397 (init_sched_context,
1398 "Initialize store pointed to by @var{tc} to hold target scheduling context.\n\
1399 It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the\n\
1400 beginning of the block. Otherwise, copy the current context into @var{tc}.",
1401 void, (void *tc, bool clean_p), NULL)
1403 /* Sets local machine scheduler context to a saved value. */
1404 DEFHOOK
1405 (set_sched_context,
1406 "Copy target scheduling context pointed to by @var{tc} to the current context.",
1407 void, (void *tc), NULL)
1409 /* Clears a scheduler context so it becomes like after init. */
1410 DEFHOOK
1411 (clear_sched_context,
1412 "Deallocate internal data in target scheduling context pointed to by @var{tc}.",
1413 void, (void *tc), NULL)
1415 /* Frees the scheduler context. */
1416 DEFHOOK
1417 (free_sched_context,
1418 "Deallocate a store for target scheduling context pointed to by @var{tc}.",
1419 void, (void *tc), NULL)
1421 /* The following member value is a pointer to a function called
1422 by the insn scheduler.
1423 The first parameter is an instruction, the second parameter is the type
1424 of the requested speculation, and the third parameter is a pointer to the
1425 speculative pattern of the corresponding type (set if return value == 1).
1426 It should return
1427 -1, if there is no pattern, that will satisfy the requested speculation type,
1428 0, if current pattern satisfies the requested speculation type,
1429 1, if pattern of the instruction should be changed to the newly
1430 generated one. */
1431 DEFHOOK
1432 (speculate_insn,
1433 "This hook is called by the insn scheduler when @var{insn} has only\n\
1434 speculative dependencies and therefore can be scheduled speculatively.\n\
1435 The hook is used to check if the pattern of @var{insn} has a speculative\n\
1436 version and, in case of successful check, to generate that speculative\n\
1437 pattern. The hook should return 1, if the instruction has a speculative form,\n\
1438 or @minus{}1, if it doesn't. @var{request} describes the type of requested\n\
1439 speculation. If the return value equals 1 then @var{new_pat} is assigned\n\
1440 the generated speculative pattern.",
1441 int, (rtx_insn *insn, unsigned int dep_status, rtx *new_pat), NULL)
1443 /* The following member value is a pointer to a function called
1444 by the insn scheduler. It should return true if the check instruction
1445 passed as the parameter needs a recovery block. */
1446 DEFHOOK
1447 (needs_block_p,
1448 "This hook is called by the insn scheduler during generation of recovery code\n\
1449 for @var{insn}. It should return @code{true}, if the corresponding check\n\
1450 instruction should branch to recovery code, or @code{false} otherwise.",
1451 bool, (unsigned int dep_status), NULL)
1453 /* The following member value is a pointer to a function called
1454 by the insn scheduler. It should return a pattern for the check
1455 instruction.
1456 The first parameter is a speculative instruction, the second parameter
1457 is the label of the corresponding recovery block (or null, if it is a
1458 simple check). The third parameter is the kind of speculation that
1459 is being performed. */
1460 DEFHOOK
1461 (gen_spec_check,
1462 "This hook is called by the insn scheduler to generate a pattern for recovery\n\
1463 check instruction. If @var{mutate_p} is zero, then @var{insn} is a\n\
1464 speculative instruction for which the check should be generated.\n\
1465 @var{label} is either a label of a basic block, where recovery code should\n\
1466 be emitted, or a null pointer, when requested check doesn't branch to\n\
1467 recovery code (a simple check). If @var{mutate_p} is nonzero, then\n\
1468 a pattern for a branchy check corresponding to a simple check denoted by\n\
1469 @var{insn} should be generated. In this case @var{label} can't be null.",
1470 rtx, (rtx_insn *insn, rtx_insn *label, unsigned int ds), NULL)
1472 /* The following member value is a pointer to a function that provides
1473 information about the speculation capabilities of the target.
1474 The parameter is a pointer to spec_info variable. */
1475 DEFHOOK
1476 (set_sched_flags,
1477 "This hook is used by the insn scheduler to find out what features should be\n\
1478 enabled/used.\n\
1479 The structure *@var{spec_info} should be filled in by the target.\n\
1480 The structure describes speculation types that can be used in the scheduler.",
1481 void, (struct spec_info_def *spec_info), NULL)
1483 DEFHOOK_UNDOC
1484 (get_insn_spec_ds,
1485 "Return speculation types of instruction @var{insn}.",
1486 unsigned int, (rtx_insn *insn), NULL)
1488 DEFHOOK_UNDOC
1489 (get_insn_checked_ds,
1490 "Return speculation types that are checked for instruction @var{insn}",
1491 unsigned int, (rtx_insn *insn), NULL)
1493 DEFHOOK
1494 (can_speculate_insn,
1495 "Some instructions should never be speculated by the schedulers, usually\n\
1496 because the instruction is too expensive to get this wrong. Often such\n\
1497 instructions have long latency, and often they are not fully modeled in the\n\
1498 pipeline descriptions. This hook should return @code{false} if @var{insn}\n\
1499 should not be speculated.",
1500 bool, (rtx_insn *insn), hook_bool_rtx_insn_true)
1502 DEFHOOK_UNDOC
1503 (skip_rtx_p,
1504 "Return bool if rtx scanning should just skip current layer and\
1505 advance to the inner rtxes.",
1506 bool, (const_rtx x), NULL)
1508 /* The following member value is a pointer to a function that provides
1509 information about the target resource-based lower bound which is
1510 used by the swing modulo scheduler. The parameter is a pointer
1511 to ddg variable. */
1512 DEFHOOK
1513 (sms_res_mii,
1514 "This hook is called by the swing modulo scheduler to calculate a\n\
1515 resource-based lower bound which is based on the resources available in\n\
1516 the machine and the resources required by each instruction. The target\n\
1517 backend can use @var{g} to calculate such bound. A very simple lower\n\
1518 bound will be used in case this hook is not implemented: the total number\n\
1519 of instructions divided by the issue rate.",
1520 int, (struct ddg *g), NULL)
1522 /* The following member value is a function that initializes dispatch
1523 schedling and adds instructions to dispatch window according to its
1524 parameters. */
1525 DEFHOOK
1526 (dispatch_do,
1527 "This hook is called by Haifa Scheduler. It performs the operation specified\n\
1528 in its second parameter.",
1529 void, (rtx_insn *insn, int x),
1530 hook_void_rtx_insn_int)
1532 /* The following member value is a a function that returns true is
1533 dispatch schedling is supported in hardware and condition passed
1534 as the second parameter is true. */
1535 DEFHOOK
1536 (dispatch,
1537 "This hook is called by Haifa Scheduler. It returns true if dispatch scheduling\n\
1538 is supported in hardware and the condition specified in the parameter is true.",
1539 bool, (rtx_insn *insn, int x),
1540 hook_bool_rtx_insn_int_false)
1542 DEFHOOKPOD
1543 (exposed_pipeline,
1544 "True if the processor has an exposed pipeline, which means that not just\n\
1545 the order of instructions is important for correctness when scheduling, but\n\
1546 also the latencies of operations.",
1547 bool, false)
1549 /* The following member value is a function that returns number
1550 of operations reassociator should try to put in parallel for
1551 statements of the given type. By default 1 is used. */
1552 DEFHOOK
1553 (reassociation_width,
1554 "This hook is called by tree reassociator to determine a level of\n\
1555 parallelism required in output calculations chain.",
1556 int, (unsigned int opc, machine_mode mode),
1557 hook_int_uint_mode_1)
1559 /* The following member value is a function that returns priority for
1560 fusion of each instruction via pointer parameters. */
1561 DEFHOOK
1562 (fusion_priority,
1563 "This hook is called by scheduling fusion pass. It calculates fusion\n\
1564 priorities for each instruction passed in by parameter. The priorities\n\
1565 are returned via pointer parameters.\n\
1567 @var{insn} is the instruction whose priorities need to be calculated.\n\
1568 @var{max_pri} is the maximum priority can be returned in any cases.\n\
1569 @var{fusion_pri} is the pointer parameter through which @var{insn}'s\n\
1570 fusion priority should be calculated and returned.\n\
1571 @var{pri} is the pointer parameter through which @var{insn}'s priority\n\
1572 should be calculated and returned.\n\
1574 Same @var{fusion_pri} should be returned for instructions which should\n\
1575 be scheduled together. Different @var{pri} should be returned for\n\
1576 instructions with same @var{fusion_pri}. @var{fusion_pri} is the major\n\
1577 sort key, @var{pri} is the minor sort key. All instructions will be\n\
1578 scheduled according to the two priorities. All priorities calculated\n\
1579 should be between 0 (exclusive) and @var{max_pri} (inclusive). To avoid\n\
1580 false dependencies, @var{fusion_pri} of instructions which need to be\n\
1581 scheduled together should be smaller than @var{fusion_pri} of irrelevant\n\
1582 instructions.\n\
1584 Given below example:\n\
1586 @smallexample\n\
1587 ldr r10, [r1, 4]\n\
1588 add r4, r4, r10\n\
1589 ldr r15, [r2, 8]\n\
1590 sub r5, r5, r15\n\
1591 ldr r11, [r1, 0]\n\
1592 add r4, r4, r11\n\
1593 ldr r16, [r2, 12]\n\
1594 sub r5, r5, r16\n\
1595 @end smallexample\n\
1597 On targets like ARM/AArch64, the two pairs of consecutive loads should be\n\
1598 merged. Since peephole2 pass can't help in this case unless consecutive\n\
1599 loads are actually next to each other in instruction flow. That's where\n\
1600 this scheduling fusion pass works. This hook calculates priority for each\n\
1601 instruction based on its fustion type, like:\n\
1603 @smallexample\n\
1604 ldr r10, [r1, 4] ; fusion_pri=99, pri=96\n\
1605 add r4, r4, r10 ; fusion_pri=100, pri=100\n\
1606 ldr r15, [r2, 8] ; fusion_pri=98, pri=92\n\
1607 sub r5, r5, r15 ; fusion_pri=100, pri=100\n\
1608 ldr r11, [r1, 0] ; fusion_pri=99, pri=100\n\
1609 add r4, r4, r11 ; fusion_pri=100, pri=100\n\
1610 ldr r16, [r2, 12] ; fusion_pri=98, pri=88\n\
1611 sub r5, r5, r16 ; fusion_pri=100, pri=100\n\
1612 @end smallexample\n\
1614 Scheduling fusion pass then sorts all ready to issue instructions according\n\
1615 to the priorities. As a result, instructions of same fusion type will be\n\
1616 pushed together in instruction flow, like:\n\
1618 @smallexample\n\
1619 ldr r11, [r1, 0]\n\
1620 ldr r10, [r1, 4]\n\
1621 ldr r15, [r2, 8]\n\
1622 ldr r16, [r2, 12]\n\
1623 add r4, r4, r10\n\
1624 sub r5, r5, r15\n\
1625 add r4, r4, r11\n\
1626 sub r5, r5, r16\n\
1627 @end smallexample\n\
1629 Now peephole2 pass can simply merge the two pairs of loads.\n\
1631 Since scheduling fusion pass relies on peephole2 to do real fusion\n\
1632 work, it is only enabled by default when peephole2 is in effect.\n\
1634 This is firstly introduced on ARM/AArch64 targets, please refer to\n\
1635 the hook implementation for how different fusion types are supported.",
1636 void, (rtx_insn *insn, int max_pri, int *fusion_pri, int *pri), NULL)
1638 HOOK_VECTOR_END (sched)
1640 /* Functions relating to OpenMP and Cilk Plus SIMD clones. */
1641 #undef HOOK_PREFIX
1642 #define HOOK_PREFIX "TARGET_SIMD_CLONE_"
1643 HOOK_VECTOR (TARGET_SIMD_CLONE, simd_clone)
1645 DEFHOOK
1646 (compute_vecsize_and_simdlen,
1647 "This hook should set @var{vecsize_mangle}, @var{vecsize_int}, @var{vecsize_float}\n\
1648 fields in @var{simd_clone} structure pointed by @var{clone_info} argument and also\n\
1649 @var{simdlen} field if it was previously 0.\n\
1650 The hook should return 0 if SIMD clones shouldn't be emitted,\n\
1651 or number of @var{vecsize_mangle} variants that should be emitted.",
1652 int, (struct cgraph_node *, struct cgraph_simd_clone *, tree, int), NULL)
1654 DEFHOOK
1655 (adjust,
1656 "This hook should add implicit @code{attribute(target(\"...\"))} attribute\n\
1657 to SIMD clone @var{node} if needed.",
1658 void, (struct cgraph_node *), NULL)
1660 DEFHOOK
1661 (usable,
1662 "This hook should return -1 if SIMD clone @var{node} shouldn't be used\n\
1663 in vectorized loops in current function, or non-negative number if it is\n\
1664 usable. In that case, the smaller the number is, the more desirable it is\n\
1665 to use it.",
1666 int, (struct cgraph_node *), NULL)
1668 HOOK_VECTOR_END (simd_clone)
1670 /* Functions relating to OpenMP SIMT vectorization transform. */
1671 #undef HOOK_PREFIX
1672 #define HOOK_PREFIX "TARGET_SIMT_"
1673 HOOK_VECTOR (TARGET_SIMT, simt)
1675 DEFHOOK
1676 (vf,
1677 "Return number of threads in SIMT thread group on the target.",
1678 int, (void), NULL)
1680 HOOK_VECTOR_END (simt)
1682 /* Functions relating to openacc. */
1683 #undef HOOK_PREFIX
1684 #define HOOK_PREFIX "TARGET_GOACC_"
1685 HOOK_VECTOR (TARGET_GOACC, goacc)
1687 DEFHOOK
1688 (validate_dims,
1689 "This hook should check the launch dimensions provided for an OpenACC\n\
1690 compute region, or routine. Defaulted values are represented as -1\n\
1691 and non-constant values as 0. The @var{fn_level} is negative for the\n\
1692 function corresponding to the compute region. For a routine is is the\n\
1693 outermost level at which partitioned execution may be spawned. The hook\n\
1694 should verify non-default values. If DECL is NULL, global defaults\n\
1695 are being validated and unspecified defaults should be filled in.\n\
1696 Diagnostics should be issued as appropriate. Return\n\
1697 true, if changes have been made. You must override this hook to\n\
1698 provide dimensions larger than 1.",
1699 bool, (tree decl, int *dims, int fn_level),
1700 default_goacc_validate_dims)
1702 DEFHOOK
1703 (dim_limit,
1704 "This hook should return the maximum size of a particular dimension,\n\
1705 or zero if unbounded.",
1706 int, (int axis),
1707 default_goacc_dim_limit)
1709 DEFHOOK
1710 (fork_join,
1711 "This hook can be used to convert IFN_GOACC_FORK and IFN_GOACC_JOIN\n\
1712 function calls to target-specific gimple, or indicate whether they\n\
1713 should be retained. It is executed during the oacc_device_lower pass.\n\
1714 It should return true, if the call should be retained. It should\n\
1715 return false, if it is to be deleted (either because target-specific\n\
1716 gimple has been inserted before it, or there is no need for it).\n\
1717 The default hook returns false, if there are no RTL expanders for them.",
1718 bool, (gcall *call, const int *dims, bool is_fork),
1719 default_goacc_fork_join)
1721 DEFHOOK
1722 (reduction,
1723 "This hook is used by the oacc_transform pass to expand calls to the\n\
1724 @var{GOACC_REDUCTION} internal function, into a sequence of gimple\n\
1725 instructions. @var{call} is gimple statement containing the call to\n\
1726 the function. This hook removes statement @var{call} after the\n\
1727 expanded sequence has been inserted. This hook is also responsible\n\
1728 for allocating any storage for reductions when necessary.",
1729 void, (gcall *call),
1730 default_goacc_reduction)
1732 HOOK_VECTOR_END (goacc)
1734 /* Functions relating to vectorization. */
1735 #undef HOOK_PREFIX
1736 #define HOOK_PREFIX "TARGET_VECTORIZE_"
1737 HOOK_VECTOR (TARGET_VECTORIZE, vectorize)
1739 /* The following member value is a pointer to a function called
1740 by the vectorizer, and return the decl of the target builtin
1741 function. */
1742 DEFHOOK
1743 (builtin_mask_for_load,
1744 "This hook should return the DECL of a function @var{f} that given an\n\
1745 address @var{addr} as an argument returns a mask @var{m} that can be\n\
1746 used to extract from two vectors the relevant data that resides in\n\
1747 @var{addr} in case @var{addr} is not properly aligned.\n\
1749 The autovectorizer, when vectorizing a load operation from an address\n\
1750 @var{addr} that may be unaligned, will generate two vector loads from\n\
1751 the two aligned addresses around @var{addr}. It then generates a\n\
1752 @code{REALIGN_LOAD} operation to extract the relevant data from the\n\
1753 two loaded vectors. The first two arguments to @code{REALIGN_LOAD},\n\
1754 @var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and\n\
1755 the third argument, @var{OFF}, defines how the data will be extracted\n\
1756 from these two vectors: if @var{OFF} is 0, then the returned vector is\n\
1757 @var{v2}; otherwise, the returned vector is composed from the last\n\
1758 @var{VS}-@var{OFF} elements of @var{v1} concatenated to the first\n\
1759 @var{OFF} elements of @var{v2}.\n\
1761 If this hook is defined, the autovectorizer will generate a call\n\
1762 to @var{f} (using the DECL tree that this hook returns) and will\n\
1763 use the return value of @var{f} as the argument @var{OFF} to\n\
1764 @code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}\n\
1765 should comply with the semantics expected by @code{REALIGN_LOAD}\n\
1766 described above.\n\
1767 If this hook is not defined, then @var{addr} will be used as\n\
1768 the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low\n\
1769 log2(@var{VS}) @minus{} 1 bits of @var{addr} will be considered.",
1770 tree, (void), NULL)
1772 /* Returns a built-in function that realizes the vectorized version of
1773 a target-independent function, or NULL_TREE if not available. */
1774 DEFHOOK
1775 (builtin_vectorized_function,
1776 "This hook should return the decl of a function that implements the\n\
1777 vectorized variant of the function with the @code{combined_fn} code\n\
1778 @var{code} or @code{NULL_TREE} if such a function is not available.\n\
1779 The return type of the vectorized function shall be of vector type\n\
1780 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1781 tree, (unsigned code, tree vec_type_out, tree vec_type_in),
1782 default_builtin_vectorized_function)
1784 /* Returns a built-in function that realizes the vectorized version of
1785 a target-specific function, or NULL_TREE if not available. */
1786 DEFHOOK
1787 (builtin_md_vectorized_function,
1788 "This hook should return the decl of a function that implements the\n\
1789 vectorized variant of target built-in function @code{fndecl}. The\n\
1790 return type of the vectorized function shall be of vector type\n\
1791 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1792 tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
1793 default_builtin_md_vectorized_function)
1795 /* Returns a function declaration for a builtin that realizes the
1796 vector conversion, or NULL_TREE if not available. */
1797 DEFHOOK
1798 (builtin_conversion,
1799 "This hook should return the DECL of a function that implements conversion of the\n\
1800 input vector of type @var{src_type} to type @var{dest_type}.\n\
1801 The value of @var{code} is one of the enumerators in @code{enum tree_code} and\n\
1802 specifies how the conversion is to be applied\n\
1803 (truncation, rounding, etc.).\n\
1805 If this hook is defined, the autovectorizer will use the\n\
1806 @code{TARGET_VECTORIZE_BUILTIN_CONVERSION} target hook when vectorizing\n\
1807 conversion. Otherwise, it will return @code{NULL_TREE}.",
1808 tree, (unsigned code, tree dest_type, tree src_type),
1809 default_builtin_vectorized_conversion)
1811 /* Cost of different vector/scalar statements in vectorization cost
1812 model. In case of misaligned vector loads and stores the cost depends
1813 on the data type and misalignment value. */
1814 DEFHOOK
1815 (builtin_vectorization_cost,
1816 "Returns cost of different scalar or vector statements for vectorization cost model.\n\
1817 For vector memory operations the cost may depend on type (@var{vectype}) and\n\
1818 misalignment value (@var{misalign}).",
1819 int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
1820 default_builtin_vectorization_cost)
1822 DEFHOOK
1823 (preferred_vector_alignment,
1824 "This hook returns the preferred alignment in bits for accesses to\n\
1825 vectors of type @var{type} in vectorized code. This might be less than\n\
1826 or greater than the ABI-defined value returned by\n\
1827 @code{TARGET_VECTOR_ALIGNMENT}. It can be equal to the alignment of\n\
1828 a single element, in which case the vectorizer will not try to optimize\n\
1829 for alignment.\n\
1831 The default hook returns @code{TYPE_ALIGN (@var{type})}, which is\n\
1832 correct for most targets.",
1833 HOST_WIDE_INT, (const_tree type),
1834 default_preferred_vector_alignment)
1836 /* Return true if vector alignment is reachable (by peeling N
1837 iterations) for the given scalar type. */
1838 DEFHOOK
1839 (vector_alignment_reachable,
1840 "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.",
1841 bool, (const_tree type, bool is_packed),
1842 default_builtin_vector_alignment_reachable)
1844 /* Return true if a vector created for vec_perm_const is valid.
1845 A NULL indicates that all constants are valid permutations. */
1846 DEFHOOK
1847 (vec_perm_const_ok,
1848 "Return true if a vector created for @code{vec_perm_const} is valid.",
1849 bool, (machine_mode, vec_perm_indices),
1850 NULL)
1852 /* Return true if the target supports misaligned store/load of a
1853 specific factor denoted in the third parameter. The last parameter
1854 is true if the access is defined in a packed struct. */
1855 DEFHOOK
1856 (support_vector_misalignment,
1857 "This hook should return true if the target supports misaligned vector\n\
1858 store/load of a specific factor denoted in the @var{misalignment}\n\
1859 parameter. The vector store/load should be of machine mode @var{mode} and\n\
1860 the elements in the vectors should be of type @var{type}. @var{is_packed}\n\
1861 parameter is true if the memory access is defined in a packed struct.",
1862 bool,
1863 (machine_mode mode, const_tree type, int misalignment, bool is_packed),
1864 default_builtin_support_vector_misalignment)
1866 /* Returns the preferred mode for SIMD operations for the specified
1867 scalar mode. */
1868 DEFHOOK
1869 (preferred_simd_mode,
1870 "This hook should return the preferred mode for vectorizing scalar\n\
1871 mode @var{mode}. The default is\n\
1872 equal to @code{word_mode}, because the vectorizer can do some\n\
1873 transformations even in absence of specialized @acronym{SIMD} hardware.",
1874 machine_mode,
1875 (scalar_mode mode),
1876 default_preferred_simd_mode)
1878 /* Returns a mask of vector sizes to iterate over when auto-vectorizing
1879 after processing the preferred one derived from preferred_simd_mode. */
1880 DEFHOOK
1881 (autovectorize_vector_sizes,
1882 "This hook should return a mask of sizes that should be iterated over\n\
1883 after trying to autovectorize using the vector size derived from the\n\
1884 mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}.\n\
1885 The default is zero which means to not iterate over other vector sizes.",
1886 unsigned int,
1887 (void),
1888 default_autovectorize_vector_sizes)
1890 /* Function to get a target mode for a vector mask. */
1891 DEFHOOK
1892 (get_mask_mode,
1893 "A vector mask is a value that holds one boolean result for every element\n\
1894 in a vector. This hook returns the machine mode that should be used to\n\
1895 represent such a mask when the vector in question is @var{length} bytes\n\
1896 long and contains @var{nunits} elements. The hook returns an empty\n\
1897 @code{opt_machine_mode} if no such mode exists.\n\
1899 The default implementation returns the mode of an integer vector that\n\
1900 is @var{length} bytes long and that contains @var{nunits} elements,\n\
1901 if such a mode exists.",
1902 opt_machine_mode,
1903 (unsigned nunits, unsigned length),
1904 default_get_mask_mode)
1906 /* Target builtin that implements vector gather operation. */
1907 DEFHOOK
1908 (builtin_gather,
1909 "Target builtin that implements vector gather operation. @var{mem_vectype}\n\
1910 is the vector type of the load and @var{index_type} is scalar type of\n\
1911 the index, scaled by @var{scale}.\n\
1912 The default is @code{NULL_TREE} which means to not vectorize gather\n\
1913 loads.",
1914 tree,
1915 (const_tree mem_vectype, const_tree index_type, int scale),
1916 NULL)
1918 /* Target builtin that implements vector scatter operation. */
1919 DEFHOOK
1920 (builtin_scatter,
1921 "Target builtin that implements vector scatter operation. @var{vectype}\n\
1922 is the vector type of the store and @var{index_type} is scalar type of\n\
1923 the index, scaled by @var{scale}.\n\
1924 The default is @code{NULL_TREE} which means to not vectorize scatter\n\
1925 stores.",
1926 tree,
1927 (const_tree vectype, const_tree index_type, int scale),
1928 NULL)
1930 /* Target function to initialize the cost model for a loop or block. */
1931 DEFHOOK
1932 (init_cost,
1933 "This hook should initialize target-specific data structures in preparation "
1934 "for modeling the costs of vectorizing a loop or basic block. The default "
1935 "allocates three unsigned integers for accumulating costs for the prologue, "
1936 "body, and epilogue of the loop or basic block. If @var{loop_info} is "
1937 "non-NULL, it identifies the loop being vectorized; otherwise a single block "
1938 "is being vectorized.",
1939 void *,
1940 (struct loop *loop_info),
1941 default_init_cost)
1943 /* Target function to record N statements of the given kind using the
1944 given vector type within the cost model data for the current loop or
1945 block. */
1946 DEFHOOK
1947 (add_stmt_cost,
1948 "This hook should update the target-specific @var{data} in response to "
1949 "adding @var{count} copies of the given @var{kind} of statement to a "
1950 "loop or basic block. The default adds the builtin vectorizer cost for "
1951 "the copies of the statement to the accumulator specified by @var{where}, "
1952 "(the prologue, body, or epilogue) and returns the amount added. The "
1953 "return value should be viewed as a tentative cost that may later be "
1954 "revised.",
1955 unsigned,
1956 (void *data, int count, enum vect_cost_for_stmt kind,
1957 struct _stmt_vec_info *stmt_info, int misalign,
1958 enum vect_cost_model_location where),
1959 default_add_stmt_cost)
1961 /* Target function to calculate the total cost of the current vectorized
1962 loop or block. */
1963 DEFHOOK
1964 (finish_cost,
1965 "This hook should complete calculations of the cost of vectorizing a loop "
1966 "or basic block based on @var{data}, and return the prologue, body, and "
1967 "epilogue costs as unsigned integers. The default returns the value of "
1968 "the three accumulators.",
1969 void,
1970 (void *data, unsigned *prologue_cost, unsigned *body_cost,
1971 unsigned *epilogue_cost),
1972 default_finish_cost)
1974 /* Function to delete target-specific cost modeling data. */
1975 DEFHOOK
1976 (destroy_cost_data,
1977 "This hook should release @var{data} and any related data structures "
1978 "allocated by TARGET_VECTORIZE_INIT_COST. The default releases the "
1979 "accumulator.",
1980 void,
1981 (void *data),
1982 default_destroy_cost_data)
1984 HOOK_VECTOR_END (vectorize)
1986 #undef HOOK_PREFIX
1987 #define HOOK_PREFIX "TARGET_"
1989 DEFHOOK
1990 (record_offload_symbol,
1991 "Used when offloaded functions are seen in the compilation unit and no named\n\
1992 sections are available. It is called once for each symbol that must be\n\
1993 recorded in the offload function and variable table.",
1994 void, (tree),
1995 hook_void_tree)
1997 DEFHOOKPOD
1998 (absolute_biggest_alignment,
1999 "If defined, this target hook specifies the absolute biggest alignment\n\
2000 that a type or variable can have on this machine, otherwise,\n\
2001 @code{BIGGEST_ALIGNMENT} is used.",
2002 HOST_WIDE_INT, BIGGEST_ALIGNMENT)
2004 /* Allow target specific overriding of option settings after options have
2005 been changed by an attribute or pragma or when it is reset at the
2006 end of the code affected by an attribute or pragma. */
2007 DEFHOOK
2008 (override_options_after_change,
2009 "This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}\n\
2010 but is called when the optimize level is changed via an attribute or\n\
2011 pragma or when it is reset at the end of the code affected by the\n\
2012 attribute or pragma. It is not called at the beginning of compilation\n\
2013 when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these\n\
2014 actions then, you should have @code{TARGET_OPTION_OVERRIDE} call\n\
2015 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.",
2016 void, (void),
2017 hook_void_void)
2019 DEFHOOK
2020 (offload_options,
2021 "Used when writing out the list of options into an LTO file. It should\n\
2022 translate any relevant target-specific options (such as the ABI in use)\n\
2023 into one of the @option{-foffload} options that exist as a common interface\n\
2024 to express such options. It should return a string containing these options,\n\
2025 separated by spaces, which the caller will free.\n",
2026 char *, (void), hook_charptr_void_null)
2028 DEFHOOK_UNDOC
2029 (eh_return_filter_mode,
2030 "Return machine mode for filter value.",
2031 scalar_int_mode, (void),
2032 default_eh_return_filter_mode)
2034 /* Return machine mode for libgcc expanded cmp instructions. */
2035 DEFHOOK
2036 (libgcc_cmp_return_mode,
2037 "This target hook should return the mode to be used for the return value\n\
2038 of compare instructions expanded to libgcc calls. If not defined\n\
2039 @code{word_mode} is returned which is the right choice for a majority of\n\
2040 targets.",
2041 scalar_int_mode, (void),
2042 default_libgcc_cmp_return_mode)
2044 /* Return machine mode for libgcc expanded shift instructions. */
2045 DEFHOOK
2046 (libgcc_shift_count_mode,
2047 "This target hook should return the mode to be used for the shift count operand\n\
2048 of shift instructions expanded to libgcc calls. If not defined\n\
2049 @code{word_mode} is returned which is the right choice for a majority of\n\
2050 targets.",
2051 scalar_int_mode, (void),
2052 default_libgcc_shift_count_mode)
2054 /* Return machine mode to be used for _Unwind_Word type. */
2055 DEFHOOK
2056 (unwind_word_mode,
2057 "Return machine mode to be used for @code{_Unwind_Word} type.\n\
2058 The default is to use @code{word_mode}.",
2059 scalar_int_mode, (void),
2060 default_unwind_word_mode)
2062 /* Given two decls, merge their attributes and return the result. */
2063 DEFHOOK
2064 (merge_decl_attributes,
2065 "Define this target hook if the merging of decl attributes needs special\n\
2066 handling. If defined, the result is a list of the combined\n\
2067 @code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.\n\
2068 @var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of\n\
2069 when this is needed are when one attribute overrides another, or when an\n\
2070 attribute is nullified by a subsequent definition. This function may\n\
2071 call @code{merge_attributes} to handle machine-independent merging.\n\
2073 @findex TARGET_DLLIMPORT_DECL_ATTRIBUTES\n\
2074 If the only target-specific handling you require is @samp{dllimport}\n\
2075 for Microsoft Windows targets, you should define the macro\n\
2076 @code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler\n\
2077 will then define a function called\n\
2078 @code{merge_dllimport_decl_attributes} which can then be defined as\n\
2079 the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also\n\
2080 add @code{handle_dll_attribute} in the attribute table for your port\n\
2081 to perform initial processing of the @samp{dllimport} and\n\
2082 @samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and\n\
2083 @file{i386/i386.c}, for example.",
2084 tree, (tree olddecl, tree newdecl),
2085 merge_decl_attributes)
2087 /* Given two types, merge their attributes and return the result. */
2088 DEFHOOK
2089 (merge_type_attributes,
2090 "Define this target hook if the merging of type attributes needs special\n\
2091 handling. If defined, the result is a list of the combined\n\
2092 @code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed\n\
2093 that @code{comptypes} has already been called and returned 1. This\n\
2094 function may call @code{merge_attributes} to handle machine-independent\n\
2095 merging.",
2096 tree, (tree type1, tree type2),
2097 merge_type_attributes)
2099 /* Table of machine attributes and functions to handle them.
2100 Ignored if NULL. */
2101 DEFHOOKPOD
2102 (attribute_table,
2103 "If defined, this target hook points to an array of @samp{struct\n\
2104 attribute_spec} (defined in @file{tree-core.h}) specifying the machine\n\
2105 specific attributes for this target and some of the restrictions on the\n\
2106 entities to which these attributes are applied and the arguments they\n\
2107 take.",
2108 const struct attribute_spec *, NULL)
2110 /* Return true iff attribute NAME expects a plain identifier as its first
2111 argument. */
2112 DEFHOOK
2113 (attribute_takes_identifier_p,
2114 "If defined, this target hook is a function which returns true if the\n\
2115 machine-specific attribute named @var{name} expects an identifier\n\
2116 given as its first argument to be passed on as a plain identifier, not\n\
2117 subjected to name lookup. If this is not defined, the default is\n\
2118 false for all machine-specific attributes.",
2119 bool, (const_tree name),
2120 hook_bool_const_tree_false)
2122 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
2123 one if they are compatible and two if they are nearly compatible
2124 (which causes a warning to be generated). */
2125 DEFHOOK
2126 (comp_type_attributes,
2127 "If defined, this target hook is a function which returns zero if the attributes on\n\
2128 @var{type1} and @var{type2} are incompatible, one if they are compatible,\n\
2129 and two if they are nearly compatible (which causes a warning to be\n\
2130 generated). If this is not defined, machine-specific attributes are\n\
2131 supposed always to be compatible.",
2132 int, (const_tree type1, const_tree type2),
2133 hook_int_const_tree_const_tree_1)
2135 /* Assign default attributes to the newly defined TYPE. */
2136 DEFHOOK
2137 (set_default_type_attributes,
2138 "If defined, this target hook is a function which assigns default attributes to\n\
2139 the newly defined @var{type}.",
2140 void, (tree type),
2141 hook_void_tree)
2143 /* Insert attributes on the newly created DECL. */
2144 DEFHOOK
2145 (insert_attributes,
2146 "Define this target hook if you want to be able to add attributes to a decl\n\
2147 when it is being created. This is normally useful for back ends which\n\
2148 wish to implement a pragma by using the attributes which correspond to\n\
2149 the pragma's effect. The @var{node} argument is the decl which is being\n\
2150 created. The @var{attr_ptr} argument is a pointer to the attribute list\n\
2151 for this decl. The list itself should not be modified, since it may be\n\
2152 shared with other decls, but attributes may be chained on the head of\n\
2153 the list and @code{*@var{attr_ptr}} modified to point to the new\n\
2154 attributes, or a copy of the list may be made if further changes are\n\
2155 needed.",
2156 void, (tree node, tree *attr_ptr),
2157 hook_void_tree_treeptr)
2159 /* Return true if FNDECL (which has at least one machine attribute)
2160 can be inlined despite its machine attributes, false otherwise. */
2161 DEFHOOK
2162 (function_attribute_inlinable_p,
2163 "@cindex inlining\n\
2164 This target hook returns @code{true} if it is OK to inline @var{fndecl}\n\
2165 into the current function, despite its having target-specific\n\
2166 attributes, @code{false} otherwise. By default, if a function has a\n\
2167 target specific attribute attached to it, it will not be inlined.",
2168 bool, (const_tree fndecl),
2169 hook_bool_const_tree_false)
2171 /* Return true if bitfields in RECORD_TYPE should follow the
2172 Microsoft Visual C++ bitfield layout rules. */
2173 DEFHOOK
2174 (ms_bitfield_layout_p,
2175 "This target hook returns @code{true} if bit-fields in the given\n\
2176 @var{record_type} are to be laid out following the rules of Microsoft\n\
2177 Visual C/C++, namely: (i) a bit-field won't share the same storage\n\
2178 unit with the previous bit-field if their underlying types have\n\
2179 different sizes, and the bit-field will be aligned to the highest\n\
2180 alignment of the underlying types of itself and of the previous\n\
2181 bit-field; (ii) a zero-sized bit-field will affect the alignment of\n\
2182 the whole enclosing structure, even if it is unnamed; except that\n\
2183 (iii) a zero-sized bit-field will be disregarded unless it follows\n\
2184 another bit-field of nonzero size. If this hook returns @code{true},\n\
2185 other macros that control bit-field layout are ignored.\n\
2187 When a bit-field is inserted into a packed record, the whole size\n\
2188 of the underlying type is used by one or more same-size adjacent\n\
2189 bit-fields (that is, if its long:3, 32 bits is used in the record,\n\
2190 and any additional adjacent long bit-fields are packed into the same\n\
2191 chunk of 32 bits. However, if the size changes, a new field of that\n\
2192 size is allocated). In an unpacked record, this is the same as using\n\
2193 alignment, but not equivalent when packing.\n\
2195 If both MS bit-fields and @samp{__attribute__((packed))} are used,\n\
2196 the latter will take precedence. If @samp{__attribute__((packed))} is\n\
2197 used on a single field when MS bit-fields are in use, it will take\n\
2198 precedence for that field, but the alignment of the rest of the structure\n\
2199 may affect its placement.",
2200 bool, (const_tree record_type),
2201 hook_bool_const_tree_false)
2203 /* For now this is only an interface to WORDS_BIG_ENDIAN for
2204 target-independent code like the front ends, need performance testing
2205 before switching completely to the target hook. */
2206 DEFHOOK_UNDOC
2207 (words_big_endian,
2209 bool, (void),
2210 targhook_words_big_endian)
2212 /* Likewise for FLOAT_WORDS_BIG_ENDIAN. */
2213 DEFHOOK_UNDOC
2214 (float_words_big_endian,
2216 bool, (void),
2217 targhook_float_words_big_endian)
2219 DEFHOOK
2220 (float_exceptions_rounding_supported_p,
2221 "Returns true if the target supports IEEE 754 floating-point exceptions\
2222 and rounding modes, false otherwise. This is intended to relate to the\
2223 @code{float} and @code{double} types, but not necessarily @code{long double}.\
2224 By default, returns true if the @code{adddf3} instruction pattern is\
2225 available and false otherwise, on the assumption that hardware floating\
2226 point supports exceptions and rounding modes but software floating point\
2227 does not.",
2228 bool, (void),
2229 default_float_exceptions_rounding_supported_p)
2231 /* True if the target supports decimal floating point. */
2232 DEFHOOK
2233 (decimal_float_supported_p,
2234 "Returns true if the target supports decimal floating point.",
2235 bool, (void),
2236 default_decimal_float_supported_p)
2238 /* True if the target supports fixed-point. */
2239 DEFHOOK
2240 (fixed_point_supported_p,
2241 "Returns true if the target supports fixed-point arithmetic.",
2242 bool, (void),
2243 default_fixed_point_supported_p)
2245 /* Return true if anonymous bitfields affect structure alignment. */
2246 DEFHOOK
2247 (align_anon_bitfield,
2248 "When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine\n\
2249 whether unnamed bitfields affect the alignment of the containing\n\
2250 structure. The hook should return true if the structure should inherit\n\
2251 the alignment requirements of an unnamed bitfield's type.",
2252 bool, (void),
2253 hook_bool_void_false)
2255 /* Return true if volatile bitfields should use the narrowest type possible.
2256 Return false if they should use the container type. */
2257 DEFHOOK
2258 (narrow_volatile_bitfield,
2259 "This target hook should return @code{true} if accesses to volatile bitfields\n\
2260 should use the narrowest mode possible. It should return @code{false} if\n\
2261 these accesses should use the bitfield container type.\n\
2263 The default is @code{false}.",
2264 bool, (void),
2265 hook_bool_void_false)
2267 /* Set up target-specific built-in functions. */
2268 DEFHOOK
2269 (init_builtins,
2270 "Define this hook if you have any machine-specific built-in functions\n\
2271 that need to be defined. It should be a function that performs the\n\
2272 necessary setup.\n\
2274 Machine specific built-in functions can be useful to expand special machine\n\
2275 instructions that would otherwise not normally be generated because\n\
2276 they have no equivalent in the source language (for example, SIMD vector\n\
2277 instructions or prefetch instructions).\n\
2279 To create a built-in function, call the function\n\
2280 @code{lang_hooks.builtin_function}\n\
2281 which is defined by the language front end. You can use any type nodes set\n\
2282 up by @code{build_common_tree_nodes};\n\
2283 only language front ends that use those two functions will call\n\
2284 @samp{TARGET_INIT_BUILTINS}.",
2285 void, (void),
2286 hook_void_void)
2288 /* Initialize (if INITIALIZE_P is true) and return the target-specific
2289 built-in function decl for CODE.
2290 Return NULL if that is not possible. Return error_mark_node if CODE
2291 is outside of the range of valid target builtin function codes. */
2292 DEFHOOK
2293 (builtin_decl,
2294 "Define this hook if you have any machine-specific built-in functions\n\
2295 that need to be defined. It should be a function that returns the\n\
2296 builtin function declaration for the builtin function code @var{code}.\n\
2297 If there is no such builtin and it cannot be initialized at this time\n\
2298 if @var{initialize_p} is true the function should return @code{NULL_TREE}.\n\
2299 If @var{code} is out of range the function should return\n\
2300 @code{error_mark_node}.",
2301 tree, (unsigned code, bool initialize_p), NULL)
2303 /* Expand a target-specific builtin. */
2304 DEFHOOK
2305 (expand_builtin,
2306 "\n\
2307 Expand a call to a machine specific built-in function that was set up by\n\
2308 @samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the\n\
2309 function call; the result should go to @var{target} if that is\n\
2310 convenient, and have mode @var{mode} if that is convenient.\n\
2311 @var{subtarget} may be used as the target for computing one of\n\
2312 @var{exp}'s operands. @var{ignore} is nonzero if the value is to be\n\
2313 ignored. This function should return the result of the call to the\n\
2314 built-in function.",
2315 rtx,
2316 (tree exp, rtx target, rtx subtarget, machine_mode mode, int ignore),
2317 default_expand_builtin)
2319 DEFHOOK
2320 (builtin_chkp_function,
2321 "This hook allows target to redefine built-in functions used by\n\
2322 Pointer Bounds Checker for code instrumentation. Hook should return\n\
2323 fndecl of function implementing generic builtin whose code is\n\
2324 passed in @var{fcode}. Currently following built-in functions are\n\
2325 obtained using this hook:\n\
2326 @deftypefn {Built-in Function} __bounds_type __chkp_bndmk (const void *@var{lb}, size_t @var{size})\n\
2327 Function code - BUILT_IN_CHKP_BNDMK. This built-in function is used\n\
2328 by Pointer Bounds Checker to create bound values. @var{lb} holds low\n\
2329 bound of the resulting bounds. @var{size} holds size of created bounds.\n\
2330 @end deftypefn\n\
2332 @deftypefn {Built-in Function} void __chkp_bndstx (const void *@var{ptr}, __bounds_type @var{b}, const void **@var{loc})\n\
2333 Function code - @code{BUILT_IN_CHKP_BNDSTX}. This built-in function is used\n\
2334 by Pointer Bounds Checker to store bounds @var{b} for pointer @var{ptr}\n\
2335 when @var{ptr} is stored by address @var{loc}.\n\
2336 @end deftypefn\n\
2338 @deftypefn {Built-in Function} __bounds_type __chkp_bndldx (const void **@var{loc}, const void *@var{ptr})\n\
2339 Function code - @code{BUILT_IN_CHKP_BNDLDX}. This built-in function is used\n\
2340 by Pointer Bounds Checker to get bounds of pointer @var{ptr} loaded by\n\
2341 address @var{loc}.\n\
2342 @end deftypefn\n\
2344 @deftypefn {Built-in Function} void __chkp_bndcl (const void *@var{ptr}, __bounds_type @var{b})\n\
2345 Function code - @code{BUILT_IN_CHKP_BNDCL}. This built-in function is used\n\
2346 by Pointer Bounds Checker to perform check for pointer @var{ptr} against\n\
2347 lower bound of bounds @var{b}.\n\
2348 @end deftypefn\n\
2350 @deftypefn {Built-in Function} void __chkp_bndcu (const void *@var{ptr}, __bounds_type @var{b})\n\
2351 Function code - @code{BUILT_IN_CHKP_BNDCU}. This built-in function is used\n\
2352 by Pointer Bounds Checker to perform check for pointer @var{ptr} against\n\
2353 upper bound of bounds @var{b}.\n\
2354 @end deftypefn\n\
2356 @deftypefn {Built-in Function} __bounds_type __chkp_bndret (void *@var{ptr})\n\
2357 Function code - @code{BUILT_IN_CHKP_BNDRET}. This built-in function is used\n\
2358 by Pointer Bounds Checker to obtain bounds returned by a call statement.\n\
2359 @var{ptr} passed to built-in is @code{SSA_NAME} returned by the call.\n\
2360 @end deftypefn\n\
2362 @deftypefn {Built-in Function} __bounds_type __chkp_intersect (__bounds_type @var{b1}, __bounds_type @var{b2})\n\
2363 Function code - @code{BUILT_IN_CHKP_INTERSECT}. This built-in function\n\
2364 returns intersection of bounds @var{b1} and @var{b2}.\n\
2365 @end deftypefn\n\
2367 @deftypefn {Built-in Function} __bounds_type __chkp_narrow (const void *@var{ptr}, __bounds_type @var{b}, size_t @var{s})\n\
2368 Function code - @code{BUILT_IN_CHKP_NARROW}. This built-in function\n\
2369 returns intersection of bounds @var{b} and\n\
2370 [@var{ptr}, @var{ptr} + @var{s} - @code{1}].\n\
2371 @end deftypefn\n\
2373 @deftypefn {Built-in Function} size_t __chkp_sizeof (const void *@var{ptr})\n\
2374 Function code - @code{BUILT_IN_CHKP_SIZEOF}. This built-in function\n\
2375 returns size of object referenced by @var{ptr}. @var{ptr} is always\n\
2376 @code{ADDR_EXPR} of @code{VAR_DECL}. This built-in is used by\n\
2377 Pointer Bounds Checker when bounds of object cannot be computed statically\n\
2378 (e.g. object has incomplete type).\n\
2379 @end deftypefn\n\
2381 @deftypefn {Built-in Function} const void *__chkp_extract_lower (__bounds_type @var{b})\n\
2382 Function code - @code{BUILT_IN_CHKP_EXTRACT_LOWER}. This built-in function\n\
2383 returns lower bound of bounds @var{b}.\n\
2384 @end deftypefn\n\
2386 @deftypefn {Built-in Function} const void *__chkp_extract_upper (__bounds_type @var{b})\n\
2387 Function code - @code{BUILT_IN_CHKP_EXTRACT_UPPER}. This built-in function\n\
2388 returns upper bound of bounds @var{b}.\n\
2389 @end deftypefn",
2390 tree, (unsigned fcode),
2391 default_builtin_chkp_function)
2393 DEFHOOK
2394 (chkp_bound_type,
2395 "Return type to be used for bounds",
2396 tree, (void),
2397 default_chkp_bound_type)
2399 DEFHOOK
2400 (chkp_bound_mode,
2401 "Return mode to be used for bounds.",
2402 machine_mode, (void),
2403 default_chkp_bound_mode)
2405 DEFHOOK
2406 (chkp_make_bounds_constant,
2407 "Return constant used to statically initialize constant bounds\n\
2408 with specified lower bound @var{lb} and upper bounds @var{ub}.",
2409 tree, (HOST_WIDE_INT lb, HOST_WIDE_INT ub),
2410 default_chkp_make_bounds_constant)
2412 DEFHOOK
2413 (chkp_initialize_bounds,
2414 "Generate a list of statements @var{stmts} to initialize pointer\n\
2415 bounds variable @var{var} with bounds @var{lb} and @var{ub}. Return\n\
2416 the number of generated statements.",
2417 int, (tree var, tree lb, tree ub, tree *stmts),
2418 default_chkp_initialize_bounds)
2420 /* Select a replacement for a target-specific builtin. This is done
2421 *before* regular type checking, and so allows the target to
2422 implement a crude form of function overloading. The result is a
2423 complete expression that implements the operation. PARAMS really
2424 has type VEC(tree,gc)*, but we don't want to include tree.h here. */
2425 DEFHOOK
2426 (resolve_overloaded_builtin,
2427 "Select a replacement for a machine specific built-in function that\n\
2428 was set up by @samp{TARGET_INIT_BUILTINS}. This is done\n\
2429 @emph{before} regular type checking, and so allows the target to\n\
2430 implement a crude form of function overloading. @var{fndecl} is the\n\
2431 declaration of the built-in function. @var{arglist} is the list of\n\
2432 arguments passed to the built-in function. The result is a\n\
2433 complete expression that implements the operation, usually\n\
2434 another @code{CALL_EXPR}.\n\
2435 @var{arglist} really has type @samp{VEC(tree,gc)*}",
2436 tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
2438 /* Fold a target-specific builtin to a tree valid for both GIMPLE
2439 and GENERIC. */
2440 DEFHOOK
2441 (fold_builtin,
2442 "Fold a call to a machine specific built-in function that was set up by\n\
2443 @samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the\n\
2444 built-in function. @var{n_args} is the number of arguments passed to\n\
2445 the function; the arguments themselves are pointed to by @var{argp}.\n\
2446 The result is another tree, valid for both GIMPLE and GENERIC,\n\
2447 containing a simplified expression for the call's result. If\n\
2448 @var{ignore} is true the value will be ignored.",
2449 tree, (tree fndecl, int n_args, tree *argp, bool ignore),
2450 hook_tree_tree_int_treep_bool_null)
2452 /* Fold a target-specific builtin to a valid GIMPLE tree. */
2453 DEFHOOK
2454 (gimple_fold_builtin,
2455 "Fold a call to a machine specific built-in function that was set up\n\
2456 by @samp{TARGET_INIT_BUILTINS}. @var{gsi} points to the gimple\n\
2457 statement holding the function call. Returns true if any change\n\
2458 was made to the GIMPLE stream.",
2459 bool, (gimple_stmt_iterator *gsi),
2460 hook_bool_gsiptr_false)
2462 /* Target hook is used to compare the target attributes in two functions to
2463 determine which function's features get higher priority. This is used
2464 during function multi-versioning to figure out the order in which two
2465 versions must be dispatched. A function version with a higher priority
2466 is checked for dispatching earlier. DECL1 and DECL2 are
2467 the two function decls that will be compared. It returns positive value
2468 if DECL1 is higher priority, negative value if DECL2 is higher priority
2469 and 0 if they are the same. */
2470 DEFHOOK
2471 (compare_version_priority,
2472 "This hook is used to compare the target attributes in two functions to\n\
2473 determine which function's features get higher priority. This is used\n\
2474 during function multi-versioning to figure out the order in which two\n\
2475 versions must be dispatched. A function version with a higher priority\n\
2476 is checked for dispatching earlier. @var{decl1} and @var{decl2} are\n\
2477 the two function decls that will be compared.",
2478 int, (tree decl1, tree decl2), NULL)
2480 /* Target hook is used to generate the dispatcher logic to invoke the right
2481 function version at run-time for a given set of function versions.
2482 ARG points to the callgraph node of the dispatcher function whose body
2483 must be generated. */
2484 DEFHOOK
2485 (generate_version_dispatcher_body,
2486 "This hook is used to generate the dispatcher logic to invoke the right\n\
2487 function version at run-time for a given set of function versions.\n\
2488 @var{arg} points to the callgraph node of the dispatcher function whose\n\
2489 body must be generated.",
2490 tree, (void *arg), NULL)
2492 /* Target hook is used to get the dispatcher function for a set of function
2493 versions. The dispatcher function is called to invoke the right function
2494 version at run-time. DECL is one version from a set of semantically
2495 identical versions. */
2496 DEFHOOK
2497 (get_function_versions_dispatcher,
2498 "This hook is used to get the dispatcher function for a set of function\n\
2499 versions. The dispatcher function is called to invoke the right function\n\
2500 version at run-time. @var{decl} is one version from a set of semantically\n\
2501 identical versions.",
2502 tree, (void *decl), NULL)
2504 /* Returns a code for a target-specific builtin that implements
2505 reciprocal of a target-specific function, or NULL_TREE if not available. */
2506 DEFHOOK
2507 (builtin_reciprocal,
2508 "This hook should return the DECL of a function that implements the\n\
2509 reciprocal of the machine-specific builtin function @var{fndecl}, or\n\
2510 @code{NULL_TREE} if such a function is not available.",
2511 tree, (tree fndecl),
2512 default_builtin_reciprocal)
2514 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
2515 string containing the C++ mangling for TYPE. In all other cases, return
2516 NULL. */
2517 DEFHOOK
2518 (mangle_type,
2519 "If your target defines any fundamental types, or any types your target\n\
2520 uses should be mangled differently from the default, define this hook\n\
2521 to return the appropriate encoding for these types as part of a C++\n\
2522 mangled name. The @var{type} argument is the tree structure representing\n\
2523 the type to be mangled. The hook may be applied to trees which are\n\
2524 not target-specific fundamental types; it should return @code{NULL}\n\
2525 for all such types, as well as arguments it does not recognize. If the\n\
2526 return value is not @code{NULL}, it must point to a statically-allocated\n\
2527 string constant.\n\
2529 Target-specific fundamental types might be new fundamental types or\n\
2530 qualified versions of ordinary fundamental types. Encode new\n\
2531 fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}\n\
2532 is the name used for the type in source code, and @var{n} is the\n\
2533 length of @var{name} in decimal. Encode qualified versions of\n\
2534 ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where\n\
2535 @var{name} is the name used for the type qualifier in source code,\n\
2536 @var{n} is the length of @var{name} as above, and @var{code} is the\n\
2537 code used to represent the unqualified version of this type. (See\n\
2538 @code{write_builtin_type} in @file{cp/mangle.c} for the list of\n\
2539 codes.) In both cases the spaces are for clarity; do not include any\n\
2540 spaces in your string.\n\
2542 This hook is applied to types prior to typedef resolution. If the mangled\n\
2543 name for a particular type depends only on that type's main variant, you\n\
2544 can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}\n\
2545 before mangling.\n\
2547 The default version of this hook always returns @code{NULL}, which is\n\
2548 appropriate for a target that does not define any new fundamental\n\
2549 types.",
2550 const char *, (const_tree type),
2551 hook_constcharptr_const_tree_null)
2553 /* Make any adjustments to libfunc names needed for this target. */
2554 DEFHOOK
2555 (init_libfuncs,
2556 "This hook should declare additional library routines or rename\n\
2557 existing ones, using the functions @code{set_optab_libfunc} and\n\
2558 @code{init_one_libfunc} defined in @file{optabs.c}.\n\
2559 @code{init_optabs} calls this macro after initializing all the normal\n\
2560 library routines.\n\
2562 The default is to do nothing. Most ports don't need to define this hook.",
2563 void, (void),
2564 hook_void_void)
2566 /* Add a __gnu_ prefix to library functions rather than just __. */
2567 DEFHOOKPOD
2568 (libfunc_gnu_prefix,
2569 "If false (the default), internal library routines start with two\n\
2570 underscores. If set to true, these routines start with @code{__gnu_}\n\
2571 instead. E.g., @code{__muldi3} changes to @code{__gnu_muldi3}. This\n\
2572 currently only affects functions defined in @file{libgcc2.c}. If this\n\
2573 is set to true, the @file{tm.h} file must also\n\
2574 @code{#define LIBGCC2_GNU_PREFIX}.",
2575 bool, false)
2577 /* Given a decl, a section name, and whether the decl initializer
2578 has relocs, choose attributes for the section. */
2579 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
2580 DEFHOOK
2581 (section_type_flags,
2582 "Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}\n\
2583 based on a variable or function decl, a section name, and whether or not the\n\
2584 declaration's initializer may contain runtime relocations. @var{decl} may be\n\
2585 null, in which case read-write data should be assumed.\n\
2587 The default version of this function handles choosing code vs data,\n\
2588 read-only vs read-write data, and @code{flag_pic}. You should only\n\
2589 need to override this if your target has special flags that might be\n\
2590 set via @code{__attribute__}.",
2591 unsigned int, (tree decl, const char *name, int reloc),
2592 default_section_type_flags)
2594 DEFHOOK
2595 (libc_has_function,
2596 "This hook determines whether a function from a class of functions\n\
2597 @var{fn_class} is present at the runtime.",
2598 bool, (enum function_class fn_class),
2599 default_libc_has_function)
2601 /* True if new jumps cannot be created, to replace existing ones or
2602 not, at the current point in the compilation. */
2603 DEFHOOK
2604 (cannot_modify_jumps_p,
2605 "This target hook returns @code{true} past the point in which new jump\n\
2606 instructions could be created. On machines that require a register for\n\
2607 every jump such as the SHmedia ISA of SH5, this point would typically be\n\
2608 reload, so this target hook should be defined to a function such as:\n\
2610 @smallexample\n\
2611 static bool\n\
2612 cannot_modify_jumps_past_reload_p ()\n\
2613 @{\n\
2614 return (reload_completed || reload_in_progress);\n\
2615 @}\n\
2616 @end smallexample",
2617 bool, (void),
2618 hook_bool_void_false)
2620 /* True if FOLLOWER may be modified to follow FOLLOWEE. */
2621 DEFHOOK
2622 (can_follow_jump,
2623 "FOLLOWER and FOLLOWEE are JUMP_INSN instructions;\
2624 return true if FOLLOWER may be modified to follow FOLLOWEE;\
2625 false, if it can't.\
2626 For example, on some targets, certain kinds of branches can't be made to\
2627 follow through a hot/cold partitioning.",
2628 bool, (const rtx_insn *follower, const rtx_insn *followee),
2629 hook_bool_const_rtx_insn_const_rtx_insn_true)
2631 /* Return a register class for which branch target register
2632 optimizations should be applied. */
2633 DEFHOOK
2634 (branch_target_register_class,
2635 "This target hook returns a register class for which branch target register\n\
2636 optimizations should be applied. All registers in this class should be\n\
2637 usable interchangeably. After reload, registers in this class will be\n\
2638 re-allocated and loads will be hoisted out of loops and be subjected\n\
2639 to inter-block scheduling.",
2640 reg_class_t, (void),
2641 default_branch_target_register_class)
2643 /* Return true if branch target register optimizations should include
2644 callee-saved registers that are not already live during the current
2645 function. AFTER_PE_GEN is true if prologues and epilogues have
2646 already been generated. */
2647 DEFHOOK
2648 (branch_target_register_callee_saved,
2649 "Branch target register optimization will by default exclude callee-saved\n\
2650 registers\n\
2651 that are not already live during the current function; if this target hook\n\
2652 returns true, they will be included. The target code must than make sure\n\
2653 that all target registers in the class returned by\n\
2654 @samp{TARGET_BRANCH_TARGET_REGISTER_CLASS} that might need saving are\n\
2655 saved. @var{after_prologue_epilogue_gen} indicates if prologues and\n\
2656 epilogues have already been generated. Note, even if you only return\n\
2657 true when @var{after_prologue_epilogue_gen} is false, you still are likely\n\
2658 to have to make special provisions in @code{INITIAL_ELIMINATION_OFFSET}\n\
2659 to reserve space for caller-saved target registers.",
2660 bool, (bool after_prologue_epilogue_gen),
2661 hook_bool_bool_false)
2663 /* Return true if the target supports conditional execution. */
2664 DEFHOOK
2665 (have_conditional_execution,
2666 "This target hook returns true if the target supports conditional execution.\n\
2667 This target hook is required only when the target has several different\n\
2668 modes and they have different conditional execution capability, such as ARM.",
2669 bool, (void),
2670 default_have_conditional_execution)
2672 DEFHOOK
2673 (gen_ccmp_first,
2674 "This function prepares to emit a comparison insn for the first compare in a\n\
2675 sequence of conditional comparisions. It returns an appropriate comparison\n\
2676 with @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2677 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2678 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2679 compares in the the conditional comparision are generated without error.\n\
2680 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.",
2681 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, int code, tree op0, tree op1),
2682 NULL)
2684 DEFHOOK
2685 (gen_ccmp_next,
2686 "This function prepares to emit a conditional comparison within a sequence\n\
2687 of conditional comparisons. It returns an appropriate comparison with\n\
2688 @code{CC} for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2689 The insns to prepare the compare are saved in @var{prep_seq} and the compare\n\
2690 insns are saved in @var{gen_seq}. They will be emitted when all the\n\
2691 compares in the conditional comparision are generated without error. The\n\
2692 @var{prev} expression is the result of a prior call to @code{gen_ccmp_first}\n\
2693 or @code{gen_ccmp_next}. It may return @code{NULL} if the combination of\n\
2694 @var{prev} and this comparison is not supported, otherwise the result must\n\
2695 be appropriate for passing to @code{gen_ccmp_next} or @code{cbranch_optab}.\n\
2696 @var{code} is the @code{rtx_code} of the compare for @var{op0} and @var{op1}.\n\
2697 @var{bit_code} is @code{AND} or @code{IOR}, which is the op on the compares.",
2698 rtx, (rtx_insn **prep_seq, rtx_insn **gen_seq, rtx prev, int cmp_code, tree op0, tree op1, int bit_code),
2699 NULL)
2701 /* Return a new value for loop unroll size. */
2702 DEFHOOK
2703 (loop_unroll_adjust,
2704 "This target hook returns a new value for the number of times @var{loop}\n\
2705 should be unrolled. The parameter @var{nunroll} is the number of times\n\
2706 the loop is to be unrolled. The parameter @var{loop} is a pointer to\n\
2707 the loop, which is going to be checked for unrolling. This target hook\n\
2708 is required only when the target has special constraints like maximum\n\
2709 number of memory accesses.",
2710 unsigned, (unsigned nunroll, struct loop *loop),
2711 NULL)
2713 /* True if X is a legitimate MODE-mode immediate operand. */
2714 DEFHOOK
2715 (legitimate_constant_p,
2716 "This hook returns true if @var{x} is a legitimate constant for a\n\
2717 @var{mode}-mode immediate operand on the target machine. You can assume that\n\
2718 @var{x} satisfies @code{CONSTANT_P}, so you need not check this.\n\
2720 The default definition returns true.",
2721 bool, (machine_mode mode, rtx x),
2722 hook_bool_mode_rtx_true)
2724 /* True if the constant X cannot be placed in the constant pool. */
2725 DEFHOOK
2726 (cannot_force_const_mem,
2727 "This hook should return true if @var{x} is of a form that cannot (or\n\
2728 should not) be spilled to the constant pool. @var{mode} is the mode\n\
2729 of @var{x}.\n\
2731 The default version of this hook returns false.\n\
2733 The primary reason to define this hook is to prevent reload from\n\
2734 deciding that a non-legitimate constant would be better reloaded\n\
2735 from the constant pool instead of spilling and reloading a register\n\
2736 holding the constant. This restriction is often true of addresses\n\
2737 of TLS symbols for various targets.",
2738 bool, (machine_mode mode, rtx x),
2739 hook_bool_mode_rtx_false)
2741 DEFHOOK_UNDOC
2742 (cannot_copy_insn_p,
2743 "True if the insn @var{x} cannot be duplicated.",
2744 bool, (rtx_insn *), NULL)
2746 /* True if X is considered to be commutative. */
2747 DEFHOOK
2748 (commutative_p,
2749 "This target hook returns @code{true} if @var{x} is considered to be commutative.\n\
2750 Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider\n\
2751 PLUS to be commutative inside a MEM@. @var{outer_code} is the rtx code\n\
2752 of the enclosing rtl, if known, otherwise it is UNKNOWN.",
2753 bool, (const_rtx x, int outer_code),
2754 hook_bool_const_rtx_commutative_p)
2756 /* True if ADDR is an address-expression whose effect depends
2757 on the mode of the memory reference it is used in. */
2758 DEFHOOK
2759 (mode_dependent_address_p,
2760 "This hook returns @code{true} if memory address @var{addr} in address\n\
2761 space @var{addrspace} can have\n\
2762 different meanings depending on the machine mode of the memory\n\
2763 reference it is used for or if the address is valid for some modes\n\
2764 but not others.\n\
2766 Autoincrement and autodecrement addresses typically have mode-dependent\n\
2767 effects because the amount of the increment or decrement is the size\n\
2768 of the operand being addressed. Some machines have other mode-dependent\n\
2769 addresses. Many RISC machines have no mode-dependent addresses.\n\
2771 You may assume that @var{addr} is a valid address for the machine.\n\
2773 The default version of this hook returns @code{false}.",
2774 bool, (const_rtx addr, addr_space_t addrspace),
2775 default_mode_dependent_address_p)
2777 /* Given an invalid address X for a given machine mode, try machine-specific
2778 ways to make it legitimate. Return X or an invalid address on failure. */
2779 DEFHOOK
2780 (legitimize_address,
2781 "This hook is given an invalid memory address @var{x} for an\n\
2782 operand of mode @var{mode} and should try to return a valid memory\n\
2783 address.\n\
2785 @findex break_out_memory_refs\n\
2786 @var{x} will always be the result of a call to @code{break_out_memory_refs},\n\
2787 and @var{oldx} will be the operand that was given to that function to produce\n\
2788 @var{x}.\n\
2790 The code of the hook should not alter the substructure of\n\
2791 @var{x}. If it transforms @var{x} into a more legitimate form, it\n\
2792 should return the new @var{x}.\n\
2794 It is not necessary for this hook to come up with a legitimate address,\n\
2795 with the exception of native TLS addresses (@pxref{Emulated TLS}).\n\
2796 The compiler has standard ways of doing so in all cases. In fact, if\n\
2797 the target supports only emulated TLS, it\n\
2798 is safe to omit this hook or make it return @var{x} if it cannot find\n\
2799 a valid way to legitimize the address. But often a machine-dependent\n\
2800 strategy can generate better code.",
2801 rtx, (rtx x, rtx oldx, machine_mode mode),
2802 default_legitimize_address)
2804 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
2805 DEFHOOK
2806 (delegitimize_address,
2807 "This hook is used to undo the possibly obfuscating effects of the\n\
2808 @code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target\n\
2809 macros. Some backend implementations of these macros wrap symbol\n\
2810 references inside an @code{UNSPEC} rtx to represent PIC or similar\n\
2811 addressing modes. This target hook allows GCC's optimizers to understand\n\
2812 the semantics of these opaque @code{UNSPEC}s by converting them back\n\
2813 into their original form.",
2814 rtx, (rtx x),
2815 delegitimize_mem_from_attrs)
2817 /* Given an RTX, return true if it is not ok to emit it into debug info
2818 section. */
2819 DEFHOOK
2820 (const_not_ok_for_debug_p,
2821 "This hook should return true if @var{x} should not be emitted into\n\
2822 debug sections.",
2823 bool, (rtx x),
2824 default_const_not_ok_for_debug_p)
2826 /* Given an address RTX, say whether it is valid. */
2827 DEFHOOK
2828 (legitimate_address_p,
2829 "A function that returns whether @var{x} (an RTX) is a legitimate memory\n\
2830 address on the target machine for a memory operand of mode @var{mode}.\n\
2832 Legitimate addresses are defined in two variants: a strict variant and a\n\
2833 non-strict one. The @var{strict} parameter chooses which variant is\n\
2834 desired by the caller.\n\
2836 The strict variant is used in the reload pass. It must be defined so\n\
2837 that any pseudo-register that has not been allocated a hard register is\n\
2838 considered a memory reference. This is because in contexts where some\n\
2839 kind of register is required, a pseudo-register with no hard register\n\
2840 must be rejected. For non-hard registers, the strict variant should look\n\
2841 up the @code{reg_renumber} array; it should then proceed using the hard\n\
2842 register number in the array, or treat the pseudo as a memory reference\n\
2843 if the array holds @code{-1}.\n\
2845 The non-strict variant is used in other passes. It must be defined to\n\
2846 accept all pseudo-registers in every context where some kind of\n\
2847 register is required.\n\
2849 Normally, constant addresses which are the sum of a @code{symbol_ref}\n\
2850 and an integer are stored inside a @code{const} RTX to mark them as\n\
2851 constant. Therefore, there is no need to recognize such sums\n\
2852 specifically as legitimate addresses. Normally you would simply\n\
2853 recognize any @code{const} as legitimate.\n\
2855 Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant\n\
2856 sums that are not marked with @code{const}. It assumes that a naked\n\
2857 @code{plus} indicates indexing. If so, then you @emph{must} reject such\n\
2858 naked constant sums as illegitimate addresses, so that none of them will\n\
2859 be given to @code{PRINT_OPERAND_ADDRESS}.\n\
2861 @cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation\n\
2862 On some machines, whether a symbolic address is legitimate depends on\n\
2863 the section that the address refers to. On these machines, define the\n\
2864 target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information\n\
2865 into the @code{symbol_ref}, and then check for it here. When you see a\n\
2866 @code{const}, you will have to look inside it to find the\n\
2867 @code{symbol_ref} in order to determine the section. @xref{Assembler\n\
2868 Format}.\n\
2870 @cindex @code{GO_IF_LEGITIMATE_ADDRESS}\n\
2871 Some ports are still using a deprecated legacy substitute for\n\
2872 this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro. This macro\n\
2873 has this syntax:\n\
2875 @example\n\
2876 #define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})\n\
2877 @end example\n\
2879 @noindent\n\
2880 and should @code{goto @var{label}} if the address @var{x} is a valid\n\
2881 address on the target machine for a memory operand of mode @var{mode}.\n\
2883 @findex REG_OK_STRICT\n\
2884 Compiler source files that want to use the strict variant of this\n\
2885 macro define the macro @code{REG_OK_STRICT}. You should use an\n\
2886 @code{#ifdef REG_OK_STRICT} conditional to define the strict variant in\n\
2887 that case and the non-strict variant otherwise.\n\
2889 Using the hook is usually simpler because it limits the number of\n\
2890 files that are recompiled when changes are made.",
2891 bool, (machine_mode mode, rtx x, bool strict),
2892 default_legitimate_address_p)
2894 /* True if the given constant can be put into an object_block. */
2895 DEFHOOK
2896 (use_blocks_for_constant_p,
2897 "This hook should return true if pool entries for constant @var{x} can\n\
2898 be placed in an @code{object_block} structure. @var{mode} is the mode\n\
2899 of @var{x}.\n\
2901 The default version returns false for all constants.",
2902 bool, (machine_mode mode, const_rtx x),
2903 hook_bool_mode_const_rtx_false)
2905 /* True if the given decl can be put into an object_block. */
2906 DEFHOOK
2907 (use_blocks_for_decl_p,
2908 "This hook should return true if pool entries for @var{decl} should\n\
2909 be placed in an @code{object_block} structure.\n\
2911 The default version returns true for all decls.",
2912 bool, (const_tree decl),
2913 hook_bool_const_tree_true)
2915 /* The minimum and maximum byte offsets for anchored addresses. */
2916 DEFHOOKPOD
2917 (min_anchor_offset,
2918 "The minimum offset that should be applied to a section anchor.\n\
2919 On most targets, it should be the smallest offset that can be\n\
2920 applied to a base register while still giving a legitimate address\n\
2921 for every mode. The default value is 0.",
2922 HOST_WIDE_INT, 0)
2924 DEFHOOKPOD
2925 (max_anchor_offset,
2926 "Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)\n\
2927 offset that should be applied to section anchors. The default\n\
2928 value is 0.",
2929 HOST_WIDE_INT, 0)
2931 /* True if section anchors can be used to access the given symbol. */
2932 DEFHOOK
2933 (use_anchors_for_symbol_p,
2934 "Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}\n\
2935 @var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and\n\
2936 @samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.\n\
2938 The default version is correct for most targets, but you might need to\n\
2939 intercept this hook to handle things like target-specific attributes\n\
2940 or target-specific sections.",
2941 bool, (const_rtx x),
2942 default_use_anchors_for_symbol_p)
2944 /* True if target supports indirect functions. */
2945 DEFHOOK
2946 (has_ifunc_p,
2947 "It returns true if the target supports GNU indirect functions.\n\
2948 The support includes the assembler, linker and dynamic linker.\n\
2949 The default value of this hook is based on target's libc.",
2950 bool, (void),
2951 default_has_ifunc_p)
2953 /* True if it is OK to do sibling call optimization for the specified
2954 call expression EXP. DECL will be the called function, or NULL if
2955 this is an indirect call. */
2956 DEFHOOK
2957 (function_ok_for_sibcall,
2958 "True if it is OK to do sibling call optimization for the specified\n\
2959 call expression @var{exp}. @var{decl} will be the called function,\n\
2960 or @code{NULL} if this is an indirect call.\n\
2962 It is not uncommon for limitations of calling conventions to prevent\n\
2963 tail calls to functions outside the current unit of translation, or\n\
2964 during PIC compilation. The hook is used to enforce these restrictions,\n\
2965 as the @code{sibcall} md pattern can not fail, or fall over to a\n\
2966 ``normal'' call. The criteria for successful sibling call optimization\n\
2967 may vary greatly between different architectures.",
2968 bool, (tree decl, tree exp),
2969 hook_bool_tree_tree_false)
2971 /* Establish appropriate back-end context for processing the function
2972 FNDECL. The argument might be NULL to indicate processing at top
2973 level, outside of any function scope. */
2974 DEFHOOK
2975 (set_current_function,
2976 "The compiler invokes this hook whenever it changes its current function\n\
2977 context (@code{cfun}). You can define this function if\n\
2978 the back end needs to perform any initialization or reset actions on a\n\
2979 per-function basis. For example, it may be used to implement function\n\
2980 attributes that affect register usage or code generation patterns.\n\
2981 The argument @var{decl} is the declaration for the new function context,\n\
2982 and may be null to indicate that the compiler has left a function context\n\
2983 and is returning to processing at the top level.\n\
2984 The default hook function does nothing.\n\
2986 GCC sets @code{cfun} to a dummy function context during initialization of\n\
2987 some parts of the back end. The hook function is not invoked in this\n\
2988 situation; you need not worry about the hook being invoked recursively,\n\
2989 or when the back end is in a partially-initialized state.\n\
2990 @code{cfun} might be @code{NULL} to indicate processing at top level,\n\
2991 outside of any function scope.",
2992 void, (tree decl), hook_void_tree)
2994 /* True if EXP should be placed in a "small data" section. */
2995 DEFHOOK
2996 (in_small_data_p,
2997 "Returns true if @var{exp} should be placed into a ``small data'' section.\n\
2998 The default version of this hook always returns false.",
2999 bool, (const_tree exp),
3000 hook_bool_const_tree_false)
3002 /* True if EXP names an object for which name resolution must resolve
3003 to the current executable or shared library. */
3004 DEFHOOK
3005 (binds_local_p,
3006 "Returns true if @var{exp} names an object for which name resolution\n\
3007 rules must resolve to the current ``module'' (dynamic shared library\n\
3008 or executable image).\n\
3010 The default version of this hook implements the name resolution rules\n\
3011 for ELF, which has a looser model of global name binding than other\n\
3012 currently supported object file formats.",
3013 bool, (const_tree exp),
3014 default_binds_local_p)
3016 /* Check if profiling code is before or after prologue. */
3017 DEFHOOK
3018 (profile_before_prologue,
3019 "It returns true if target wants profile code emitted before prologue.\n\n\
3020 The default version of this hook use the target macro\n\
3021 @code{PROFILE_BEFORE_PROLOGUE}.",
3022 bool, (void),
3023 default_profile_before_prologue)
3025 /* Return true if a leaf function should stay leaf even with profiling
3026 enabled. */
3027 DEFHOOK
3028 (keep_leaf_when_profiled,
3029 "This target hook returns true if the target wants the leaf flag for\
3030 the current function to stay true even if it calls mcount. This might\
3031 make sense for targets using the leaf flag only to determine whether a\
3032 stack frame needs to be generated or not and for which the call to\
3033 mcount is generated before the function prologue.",
3034 bool, (void),
3035 default_keep_leaf_when_profiled)
3037 /* Modify and return the identifier of a DECL's external name,
3038 originally identified by ID, as required by the target,
3039 (eg, append @nn to windows32 stdcall function names).
3040 The default is to return ID without modification. */
3041 DEFHOOK
3042 (mangle_decl_assembler_name,
3043 "Define this hook if you need to postprocess the assembler name generated\n\
3044 by target-independent code. The @var{id} provided to this hook will be\n\
3045 the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,\n\
3046 or the mangled name of the @var{decl} in C++). The return value of the\n\
3047 hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on\n\
3048 your target system. The default implementation of this hook just\n\
3049 returns the @var{id} provided.",
3050 tree, (tree decl, tree id),
3051 default_mangle_decl_assembler_name)
3053 /* Do something target-specific to record properties of the DECL into
3054 the associated SYMBOL_REF. */
3055 DEFHOOK
3056 (encode_section_info,
3057 "Define this hook if references to a symbol or a constant must be\n\
3058 treated differently depending on something about the variable or\n\
3059 function named by the symbol (such as what section it is in).\n\
3061 The hook is executed immediately after rtl has been created for\n\
3062 @var{decl}, which may be a variable or function declaration or\n\
3063 an entry in the constant pool. In either case, @var{rtl} is the\n\
3064 rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}\n\
3065 in this hook; that field may not have been initialized yet.\n\
3067 In the case of a constant, it is safe to assume that the rtl is\n\
3068 a @code{mem} whose address is a @code{symbol_ref}. Most decls\n\
3069 will also have this form, but that is not guaranteed. Global\n\
3070 register variables, for instance, will have a @code{reg} for their\n\
3071 rtl. (Normally the right thing to do with such unusual rtl is\n\
3072 leave it alone.)\n\
3074 The @var{new_decl_p} argument will be true if this is the first time\n\
3075 that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will\n\
3076 be false for subsequent invocations, which will happen for duplicate\n\
3077 declarations. Whether or not anything must be done for the duplicate\n\
3078 declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.\n\
3079 @var{new_decl_p} is always true when the hook is called for a constant.\n\
3081 @cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}\n\
3082 The usual thing for this hook to do is to record flags in the\n\
3083 @code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.\n\
3084 Historically, the name string was modified if it was necessary to\n\
3085 encode more than one bit of information, but this practice is now\n\
3086 discouraged; use @code{SYMBOL_REF_FLAGS}.\n\
3088 The default definition of this hook, @code{default_encode_section_info}\n\
3089 in @file{varasm.c}, sets a number of commonly-useful bits in\n\
3090 @code{SYMBOL_REF_FLAGS}. Check whether the default does what you need\n\
3091 before overriding it.",
3092 void, (tree decl, rtx rtl, int new_decl_p),
3093 default_encode_section_info)
3095 /* Undo the effects of encode_section_info on the symbol string. */
3096 DEFHOOK
3097 (strip_name_encoding,
3098 "Decode @var{name} and return the real name part, sans\n\
3099 the characters that @code{TARGET_ENCODE_SECTION_INFO}\n\
3100 may have added.",
3101 const char *, (const char *name),
3102 default_strip_name_encoding)
3104 /* If shift optabs for MODE are known to always truncate the shift count,
3105 return the mask that they apply. Return 0 otherwise. */
3106 DEFHOOK
3107 (shift_truncation_mask,
3108 "This function describes how the standard shift patterns for @var{mode}\n\
3109 deal with shifts by negative amounts or by more than the width of the mode.\n\
3110 @xref{shift patterns}.\n\
3112 On many machines, the shift patterns will apply a mask @var{m} to the\n\
3113 shift count, meaning that a fixed-width shift of @var{x} by @var{y} is\n\
3114 equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If\n\
3115 this is true for mode @var{mode}, the function should return @var{m},\n\
3116 otherwise it should return 0. A return value of 0 indicates that no\n\
3117 particular behavior is guaranteed.\n\
3119 Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does\n\
3120 @emph{not} apply to general shift rtxes; it applies only to instructions\n\
3121 that are generated by the named shift patterns.\n\
3123 The default implementation of this function returns\n\
3124 @code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}\n\
3125 and 0 otherwise. This definition is always safe, but if\n\
3126 @code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns\n\
3127 nevertheless truncate the shift count, you may get better code\n\
3128 by overriding it.",
3129 unsigned HOST_WIDE_INT, (machine_mode mode),
3130 default_shift_truncation_mask)
3132 /* Return the number of divisions in the given MODE that should be present,
3133 so that it is profitable to turn the division into a multiplication by
3134 the reciprocal. */
3135 DEFHOOK
3136 (min_divisions_for_recip_mul,
3137 "When @option{-ffast-math} is in effect, GCC tries to optimize\n\
3138 divisions by the same divisor, by turning them into multiplications by\n\
3139 the reciprocal. This target hook specifies the minimum number of divisions\n\
3140 that should be there for GCC to perform the optimization for a variable\n\
3141 of mode @var{mode}. The default implementation returns 3 if the machine\n\
3142 has an instruction for the division, and 2 if it does not.",
3143 unsigned int, (machine_mode mode),
3144 default_min_divisions_for_recip_mul)
3146 DEFHOOK
3147 (truly_noop_truncation,
3148 "This hook returns true if it is safe to ``convert'' a value of\n\
3149 @var{inprec} bits to one of @var{outprec} bits (where @var{outprec} is\n\
3150 smaller than @var{inprec}) by merely operating on it as if it had only\n\
3151 @var{outprec} bits. The default returns true unconditionally, which\n\
3152 is correct for most machines.\n\
3154 If @code{TARGET_MODES_TIEABLE_P} returns false for a pair of modes,\n\
3155 suboptimal code can result if this hook returns true for the corresponding\n\
3156 mode sizes. Making this hook return false in such cases may improve things.",
3157 bool, (unsigned int outprec, unsigned int inprec),
3158 hook_bool_uint_uint_true)
3160 /* If the representation of integral MODE is such that values are
3161 always sign-extended to a wider mode MODE_REP then return
3162 SIGN_EXTEND. Return UNKNOWN otherwise. */
3163 /* Note that the return type ought to be RTX_CODE, but that's not
3164 necessarily defined at this point. */
3165 DEFHOOK
3166 (mode_rep_extended,
3167 "The representation of an integral mode can be such that the values\n\
3168 are always extended to a wider integral mode. Return\n\
3169 @code{SIGN_EXTEND} if values of @var{mode} are represented in\n\
3170 sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}\n\
3171 otherwise. (Currently, none of the targets use zero-extended\n\
3172 representation this way so unlike @code{LOAD_EXTEND_OP},\n\
3173 @code{TARGET_MODE_REP_EXTENDED} is expected to return either\n\
3174 @code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends\n\
3175 @var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next\n\
3176 widest integral mode and currently we take advantage of this fact.)\n\
3178 Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}\n\
3179 value even if the extension is not performed on certain hard registers\n\
3180 as long as for the @code{REGNO_REG_CLASS} of these hard registers\n\
3181 @code{TARGET_CAN_CHANGE_MODE_CLASS} returns false.\n\
3183 Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}\n\
3184 describe two related properties. If you define\n\
3185 @code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want\n\
3186 to define @code{LOAD_EXTEND_OP (mode)} to return the same type of\n\
3187 extension.\n\
3189 In order to enforce the representation of @code{mode},\n\
3190 @code{TARGET_TRULY_NOOP_TRUNCATION} should return false when truncating to\n\
3191 @code{mode}.",
3192 int, (scalar_int_mode mode, scalar_int_mode rep_mode),
3193 default_mode_rep_extended)
3195 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
3196 DEFHOOK
3197 (valid_pointer_mode,
3198 "Define this to return nonzero if the port can handle pointers\n\
3199 with machine mode @var{mode}. The default version of this\n\
3200 hook returns true for both @code{ptr_mode} and @code{Pmode}.",
3201 bool, (scalar_int_mode mode),
3202 default_valid_pointer_mode)
3204 /* Disambiguate with errno. */
3205 DEFHOOK
3206 (ref_may_alias_errno,
3207 "Define this to return nonzero if the memory reference @var{ref}\
3208 may alias with the system C library errno location. The default\
3209 version of this hook assumes the system C library errno location\
3210 is either a declaration of type int or accessed by dereferencing\
3211 a pointer to int.",
3212 bool, (struct ao_ref *ref),
3213 default_ref_may_alias_errno)
3215 /* Support for named address spaces. */
3216 #undef HOOK_PREFIX
3217 #define HOOK_PREFIX "TARGET_ADDR_SPACE_"
3218 HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)
3220 /* MODE to use for a pointer into another address space. */
3221 DEFHOOK
3222 (pointer_mode,
3223 "Define this to return the machine mode to use for pointers to\n\
3224 @var{address_space} if the target supports named address spaces.\n\
3225 The default version of this hook returns @code{ptr_mode}.",
3226 scalar_int_mode, (addr_space_t address_space),
3227 default_addr_space_pointer_mode)
3229 /* MODE to use for an address in another address space. */
3230 DEFHOOK
3231 (address_mode,
3232 "Define this to return the machine mode to use for addresses in\n\
3233 @var{address_space} if the target supports named address spaces.\n\
3234 The default version of this hook returns @code{Pmode}.",
3235 scalar_int_mode, (addr_space_t address_space),
3236 default_addr_space_address_mode)
3238 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
3239 in another address space. */
3240 DEFHOOK
3241 (valid_pointer_mode,
3242 "Define this to return nonzero if the port can handle pointers\n\
3243 with machine mode @var{mode} to address space @var{as}. This target\n\
3244 hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,\n\
3245 except that it includes explicit named address space support. The default\n\
3246 version of this hook returns true for the modes returned by either the\n\
3247 @code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}\n\
3248 target hooks for the given address space.",
3249 bool, (scalar_int_mode mode, addr_space_t as),
3250 default_addr_space_valid_pointer_mode)
3252 /* True if an address is a valid memory address to a given named address
3253 space for a given mode. */
3254 DEFHOOK
3255 (legitimate_address_p,
3256 "Define this to return true if @var{exp} is a valid address for mode\n\
3257 @var{mode} in the named address space @var{as}. The @var{strict}\n\
3258 parameter says whether strict addressing is in effect after reload has\n\
3259 finished. This target hook is the same as the\n\
3260 @code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes\n\
3261 explicit named address space support.",
3262 bool, (machine_mode mode, rtx exp, bool strict, addr_space_t as),
3263 default_addr_space_legitimate_address_p)
3265 /* Return an updated address to convert an invalid pointer to a named
3266 address space to a valid one. If NULL_RTX is returned use machine
3267 independent methods to make the address valid. */
3268 DEFHOOK
3269 (legitimize_address,
3270 "Define this to modify an invalid address @var{x} to be a valid address\n\
3271 with mode @var{mode} in the named address space @var{as}. This target\n\
3272 hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,\n\
3273 except that it includes explicit named address space support.",
3274 rtx, (rtx x, rtx oldx, machine_mode mode, addr_space_t as),
3275 default_addr_space_legitimize_address)
3277 /* True if one named address space is a subset of another named address. */
3278 DEFHOOK
3279 (subset_p,
3280 "Define this to return whether the @var{subset} named address space is\n\
3281 contained within the @var{superset} named address space. Pointers to\n\
3282 a named address space that is a subset of another named address space\n\
3283 will be converted automatically without a cast if used together in\n\
3284 arithmetic operations. Pointers to a superset address space can be\n\
3285 converted to pointers to a subset address space via explicit casts.",
3286 bool, (addr_space_t subset, addr_space_t superset),
3287 default_addr_space_subset_p)
3289 /* True if 0 is a valid address in the address space, or false if
3290 0 is a NULL in the address space. */
3291 DEFHOOK
3292 (zero_address_valid,
3293 "Define this to modify the default handling of address 0 for the\n\
3294 address space. Return true if 0 should be considered a valid address.",
3295 bool, (addr_space_t as),
3296 default_addr_space_zero_address_valid)
3298 /* Function to convert an rtl expression from one address space to another. */
3299 DEFHOOK
3300 (convert,
3301 "Define this to convert the pointer expression represented by the RTL\n\
3302 @var{op} with type @var{from_type} that points to a named address\n\
3303 space to a new pointer expression with type @var{to_type} that points\n\
3304 to a different named address space. When this hook it called, it is\n\
3305 guaranteed that one of the two address spaces is a subset of the other,\n\
3306 as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.",
3307 rtx, (rtx op, tree from_type, tree to_type),
3308 default_addr_space_convert)
3310 /* Function to encode an address space into dwarf. */
3311 DEFHOOK
3312 (debug,
3313 "Define this to define how the address space is encoded in dwarf.\n\
3314 The result is the value to be used with @code{DW_AT_address_class}.",
3315 int, (addr_space_t as),
3316 default_addr_space_debug)
3318 /* Function to emit custom diagnostic if an address space is used. */
3319 DEFHOOK
3320 (diagnose_usage,
3321 "Define this hook if the availability of an address space depends on\n\
3322 command line options and some diagnostics should be printed when the\n\
3323 address space is used. This hook is called during parsing and allows\n\
3324 to emit a better diagnostic compared to the case where the address space\n\
3325 was not registered with @code{c_register_addr_space}. @var{as} is\n\
3326 the address space as registered with @code{c_register_addr_space}.\n\
3327 @var{loc} is the location of the address space qualifier token.\n\
3328 The default implementation does nothing.",
3329 void, (addr_space_t as, location_t loc),
3330 default_addr_space_diagnose_usage)
3332 HOOK_VECTOR_END (addr_space)
3334 #undef HOOK_PREFIX
3335 #define HOOK_PREFIX "TARGET_"
3337 DEFHOOK
3338 (static_rtx_alignment,
3339 "This hook returns the preferred alignment in bits for a\n\
3340 statically-allocated rtx, such as a constant pool entry. @var{mode}\n\
3341 is the mode of the rtx. The default implementation returns\n\
3342 @samp{GET_MODE_ALIGNMENT (@var{mode})}.",
3343 HOST_WIDE_INT, (machine_mode mode),
3344 default_static_rtx_alignment)
3346 DEFHOOK
3347 (constant_alignment,
3348 "This hook returns the alignment in bits of a constant that is being\n\
3349 placed in memory. @var{constant} is the constant and @var{basic_align}\n\
3350 is the alignment that the object would ordinarily have.\n\
3352 The default definition just returns @var{basic_align}.\n\
3354 The typical use of this hook is to increase alignment for string\n\
3355 constants to be word aligned so that @code{strcpy} calls that copy\n\
3356 constants can be done inline. The function\n\
3357 @code{constant_alignment_word_strings} provides such a definition.",
3358 HOST_WIDE_INT, (const_tree constant, HOST_WIDE_INT basic_align),
3359 default_constant_alignment)
3361 /* True if MODE is valid for the target. By "valid", we mean able to
3362 be manipulated in non-trivial ways. In particular, this means all
3363 the arithmetic is supported. */
3364 DEFHOOK
3365 (scalar_mode_supported_p,
3366 "Define this to return nonzero if the port is prepared to handle\n\
3367 insns involving scalar mode @var{mode}. For a scalar mode to be\n\
3368 considered supported, all the basic arithmetic and comparisons\n\
3369 must work.\n\
3371 The default version of this hook returns true for any mode\n\
3372 required to handle the basic C types (as defined by the port).\n\
3373 Included here are the double-word arithmetic supported by the\n\
3374 code in @file{optabs.c}.",
3375 bool, (scalar_mode mode),
3376 default_scalar_mode_supported_p)
3378 /* Similarly for vector modes. "Supported" here is less strict. At
3379 least some operations are supported; need to check optabs or builtins
3380 for further details. */
3381 DEFHOOK
3382 (vector_mode_supported_p,
3383 "Define this to return nonzero if the port is prepared to handle\n\
3384 insns involving vector mode @var{mode}. At the very least, it\n\
3385 must have move patterns for this mode.",
3386 bool, (machine_mode mode),
3387 hook_bool_mode_false)
3389 DEFHOOK
3390 (vector_alignment,
3391 "This hook can be used to define the alignment for a vector of type\n\
3392 @var{type}, in order to comply with a platform ABI. The default is to\n\
3393 require natural alignment for vector types. The alignment returned by\n\
3394 this hook must be a power-of-two multiple of the default alignment of\n\
3395 the vector element type.",
3396 HOST_WIDE_INT, (const_tree type),
3397 default_vector_alignment)
3399 /* True if we should try to use a scalar mode to represent an array,
3400 overriding the usual MAX_FIXED_MODE limit. */
3401 DEFHOOK
3402 (array_mode_supported_p,
3403 "Return true if GCC should try to use a scalar mode to store an array\n\
3404 of @var{nelems} elements, given that each element has mode @var{mode}.\n\
3405 Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
3406 and allows GCC to use any defined integer mode.\n\
3408 One use of this hook is to support vector load and store operations\n\
3409 that operate on several homogeneous vectors. For example, ARM NEON\n\
3410 has operations like:\n\
3412 @smallexample\n\
3413 int8x8x3_t vld3_s8 (const int8_t *)\n\
3414 @end smallexample\n\
3416 where the return type is defined as:\n\
3418 @smallexample\n\
3419 typedef struct int8x8x3_t\n\
3420 @{\n\
3421 int8x8_t val[3];\n\
3422 @} int8x8x3_t;\n\
3423 @end smallexample\n\
3425 If this hook allows @code{val} to have a scalar mode, then\n\
3426 @code{int8x8x3_t} can have the same mode. GCC can then store\n\
3427 @code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
3428 bool, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3429 hook_bool_mode_uhwi_false)
3431 DEFHOOK
3432 (libgcc_floating_mode_supported_p,
3433 "Define this to return nonzero if libgcc provides support for the \n\
3434 floating-point mode @var{mode}, which is known to pass \n\
3435 @code{TARGET_SCALAR_MODE_SUPPORTED_P}. The default version of this \n\
3436 hook returns true for all of @code{SFmode}, @code{DFmode}, \n\
3437 @code{XFmode} and @code{TFmode}, if such modes exist.",
3438 bool, (scalar_float_mode mode),
3439 default_libgcc_floating_mode_supported_p)
3441 DEFHOOK
3442 (floatn_mode,
3443 "Define this to return the machine mode to use for the type \n\
3444 @code{_Float@var{n}}, if @var{extended} is false, or the type \n\
3445 @code{_Float@var{n}x}, if @var{extended} is true. If such a type is not\n\
3446 supported, return @code{opt_scalar_float_mode ()}. The default version of\n\
3447 this hook returns @code{SFmode} for @code{_Float32}, @code{DFmode} for\n\
3448 @code{_Float64} and @code{_Float32x} and @code{TFmode} for \n\
3449 @code{_Float128}, if those modes exist and satisfy the requirements for \n\
3450 those types and pass @code{TARGET_SCALAR_MODE_SUPPORTED_P} and \n\
3451 @code{TARGET_LIBGCC_FLOATING_MODE_SUPPORTED_P}; for @code{_Float64x}, it \n\
3452 returns the first of @code{XFmode} and @code{TFmode} that exists and \n\
3453 satisfies the same requirements; for other types, it returns \n\
3454 @code{opt_scalar_float_mode ()}. The hook is only called for values\n\
3455 of @var{n} and @var{extended} that are valid according to\n\
3456 ISO/IEC TS 18661-3:2015; that is, @var{n} is one of 32, 64, 128, or,\n\
3457 if @var{extended} is false, 16 or greater than 128 and a multiple of 32.",
3458 opt_scalar_float_mode, (int n, bool extended),
3459 default_floatn_mode)
3461 DEFHOOK
3462 (floatn_builtin_p,
3463 "Define this to return true if the @code{_Float@var{n}} and\n\
3464 @code{_Float@var{n}x} built-in functions should implicitly enable the\n\
3465 built-in function without the @code{__builtin_} prefix in addition to the\n\
3466 normal built-in function with the @code{__builtin_} prefix. The default is\n\
3467 to only enable built-in functions without the @code{__builtin_} prefix for\n\
3468 the GNU C langauge. In strict ANSI/ISO mode, the built-in function without\n\
3469 the @code{__builtin_} prefix is not enabled. The argument @code{FUNC} is the\n\
3470 @code{enum built_in_function} id of the function to be enabled.",
3471 bool, (int func),
3472 default_floatn_builtin_p)
3474 /* Compute cost of moving data from a register of class FROM to one of
3475 TO, using MODE. */
3476 DEFHOOK
3477 (register_move_cost,
3478 "This target hook should return the cost of moving data of mode @var{mode}\n\
3479 from a register in class @var{from} to one in class @var{to}. The classes\n\
3480 are expressed using the enumeration values such as @code{GENERAL_REGS}.\n\
3481 A value of 2 is the default; other values are interpreted relative to\n\
3482 that.\n\
3484 It is not required that the cost always equal 2 when @var{from} is the\n\
3485 same as @var{to}; on some machines it is expensive to move between\n\
3486 registers if they are not general registers.\n\
3488 If reload sees an insn consisting of a single @code{set} between two\n\
3489 hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their\n\
3490 classes returns a value of 2, reload does not check to ensure that the\n\
3491 constraints of the insn are met. Setting a cost of other than 2 will\n\
3492 allow reload to verify that the constraints are met. You should do this\n\
3493 if the @samp{mov@var{m}} pattern's constraints do not allow such copying.\n\
3495 The default version of this function returns 2.",
3496 int, (machine_mode mode, reg_class_t from, reg_class_t to),
3497 default_register_move_cost)
3499 /* Compute cost of moving registers to/from memory. */
3500 /* ??? Documenting the argument types for this hook requires a GFDL
3501 license grant. Also, the documentation uses a different name for RCLASS. */
3502 DEFHOOK
3503 (memory_move_cost,
3504 "This target hook should return the cost of moving data of mode @var{mode}\n\
3505 between a register of class @var{rclass} and memory; @var{in} is @code{false}\n\
3506 if the value is to be written to memory, @code{true} if it is to be read in.\n\
3507 This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.\n\
3508 If moving between registers and memory is more expensive than between two\n\
3509 registers, you should add this target hook to express the relative cost.\n\
3511 If you do not add this target hook, GCC uses a default cost of 4 plus\n\
3512 the cost of copying via a secondary reload register, if one is\n\
3513 needed. If your machine requires a secondary reload register to copy\n\
3514 between memory and a register of @var{rclass} but the reload mechanism is\n\
3515 more complex than copying via an intermediate, use this target hook to\n\
3516 reflect the actual cost of the move.\n\
3518 GCC defines the function @code{memory_move_secondary_cost} if\n\
3519 secondary reloads are needed. It computes the costs due to copying via\n\
3520 a secondary register. If your machine copies from memory using a\n\
3521 secondary register in the conventional way but the default base value of\n\
3522 4 is not correct for your machine, use this target hook to add some other\n\
3523 value to the result of that function. The arguments to that function\n\
3524 are the same as to this target hook.",
3525 int, (machine_mode mode, reg_class_t rclass, bool in),
3526 default_memory_move_cost)
3528 DEFHOOK
3529 (use_by_pieces_infrastructure_p,
3530 "GCC will attempt several strategies when asked to copy between\n\
3531 two areas of memory, or to set, clear or store to memory, for example\n\
3532 when copying a @code{struct}. The @code{by_pieces} infrastructure\n\
3533 implements such memory operations as a sequence of load, store or move\n\
3534 insns. Alternate strategies are to expand the\n\
3535 @code{movmem} or @code{setmem} optabs, to emit a library call, or to emit\n\
3536 unit-by-unit, loop-based operations.\n\
3538 This target hook should return true if, for a memory operation with a\n\
3539 given @var{size} and @var{alignment}, using the @code{by_pieces}\n\
3540 infrastructure is expected to result in better code generation.\n\
3541 Both @var{size} and @var{alignment} are measured in terms of storage\n\
3542 units.\n\
3544 The parameter @var{op} is one of: @code{CLEAR_BY_PIECES},\n\
3545 @code{MOVE_BY_PIECES}, @code{SET_BY_PIECES}, @code{STORE_BY_PIECES} or\n\
3546 @code{COMPARE_BY_PIECES}. These describe the type of memory operation\n\
3547 under consideration.\n\
3549 The parameter @var{speed_p} is true if the code is currently being\n\
3550 optimized for speed rather than size.\n\
3552 Returning true for higher values of @var{size} can improve code generation\n\
3553 for speed if the target does not provide an implementation of the\n\
3554 @code{movmem} or @code{setmem} standard names, if the @code{movmem} or\n\
3555 @code{setmem} implementation would be more expensive than a sequence of\n\
3556 insns, or if the overhead of a library call would dominate that of\n\
3557 the body of the memory operation.\n\
3559 Returning true for higher values of @code{size} may also cause an increase\n\
3560 in code size, for example where the number of insns emitted to perform a\n\
3561 move would be greater than that of a library call.",
3562 bool, (unsigned HOST_WIDE_INT size, unsigned int alignment,
3563 enum by_pieces_operation op, bool speed_p),
3564 default_use_by_pieces_infrastructure_p)
3566 DEFHOOK
3567 (compare_by_pieces_branch_ratio,
3568 "When expanding a block comparison in MODE, gcc can try to reduce the\n\
3569 number of branches at the expense of more memory operations. This hook\n\
3570 allows the target to override the default choice. It should return the\n\
3571 factor by which branches should be reduced over the plain expansion with\n\
3572 one comparison per @var{mode}-sized piece. A port can also prevent a\n\
3573 particular mode from being used for block comparisons by returning a\n\
3574 negative number from this hook.",
3575 int, (machine_mode mode),
3576 default_compare_by_pieces_branch_ratio)
3578 DEFHOOK
3579 (slow_unaligned_access,
3580 "This hook returns true if memory accesses described by the\n\
3581 @var{mode} and @var{alignment} parameters have a cost many times greater\n\
3582 than aligned accesses, for example if they are emulated in a trap handler.\n\
3583 This hook is invoked only for unaligned accesses, i.e. when\n\
3584 @code{@var{alignment} < GET_MODE_ALIGNMENT (@var{mode})}.\n\
3586 When this hook returns true, the compiler will act as if\n\
3587 @code{STRICT_ALIGNMENT} were true when generating code for block\n\
3588 moves. This can cause significantly more instructions to be produced.\n\
3589 Therefore, do not make this hook return true if unaligned accesses only\n\
3590 add a cycle or two to the time for a memory access.\n\
3592 The hook must return true whenever @code{STRICT_ALIGNMENT} is true.\n\
3593 The default implementation returns @code{STRICT_ALIGNMENT}.",
3594 bool, (machine_mode mode, unsigned int align),
3595 default_slow_unaligned_access)
3597 DEFHOOK
3598 (optab_supported_p,
3599 "Return true if the optimizers should use optab @var{op} with\n\
3600 modes @var{mode1} and @var{mode2} for optimization type @var{opt_type}.\n\
3601 The optab is known to have an associated @file{.md} instruction\n\
3602 whose C condition is true. @var{mode2} is only meaningful for conversion\n\
3603 optabs; for direct optabs it is a copy of @var{mode1}.\n\
3605 For example, when called with @var{op} equal to @code{rint_optab} and\n\
3606 @var{mode1} equal to @code{DFmode}, the hook should say whether the\n\
3607 optimizers should use optab @code{rintdf2}.\n\
3609 The default hook returns true for all inputs.",
3610 bool, (int op, machine_mode mode1, machine_mode mode2,
3611 optimization_type opt_type),
3612 default_optab_supported_p)
3614 /* True for MODE if the target expects that registers in this mode will
3615 be allocated to registers in a small register class. The compiler is
3616 allowed to use registers explicitly used in the rtl as spill registers
3617 but it should prevent extending the lifetime of these registers. */
3618 DEFHOOK
3619 (small_register_classes_for_mode_p,
3620 "Define this to return nonzero for machine modes for which the port has\n\
3621 small register classes. If this target hook returns nonzero for a given\n\
3622 @var{mode}, the compiler will try to minimize the lifetime of registers\n\
3623 in @var{mode}. The hook may be called with @code{VOIDmode} as argument.\n\
3624 In this case, the hook is expected to return nonzero if it returns nonzero\n\
3625 for any mode.\n\
3627 On some machines, it is risky to let hard registers live across arbitrary\n\
3628 insns. Typically, these machines have instructions that require values\n\
3629 to be in specific registers (like an accumulator), and reload will fail\n\
3630 if the required hard register is used for another purpose across such an\n\
3631 insn.\n\
3633 Passes before reload do not know which hard registers will be used\n\
3634 in an instruction, but the machine modes of the registers set or used in\n\
3635 the instruction are already known. And for some machines, register\n\
3636 classes are small for, say, integer registers but not for floating point\n\
3637 registers. For example, the AMD x86-64 architecture requires specific\n\
3638 registers for the legacy x86 integer instructions, but there are many\n\
3639 SSE registers for floating point operations. On such targets, a good\n\
3640 strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}\n\
3641 machine modes but zero for the SSE register classes.\n\
3643 The default version of this hook returns false for any mode. It is always\n\
3644 safe to redefine this hook to return with a nonzero value. But if you\n\
3645 unnecessarily define it, you will reduce the amount of optimizations\n\
3646 that can be performed in some cases. If you do not define this hook\n\
3647 to return a nonzero value when it is required, the compiler will run out\n\
3648 of spill registers and print a fatal error message.",
3649 bool, (machine_mode mode),
3650 hook_bool_mode_false)
3652 /* Register number for a flags register. Only needs to be defined if the
3653 target is constrainted to use post-reload comparison elimination. */
3654 DEFHOOKPOD
3655 (flags_regnum,
3656 "If the target has a dedicated flags register, and it needs to use the\
3657 post-reload comparison elimination pass, then this value should be set\
3658 appropriately.",
3659 unsigned int, INVALID_REGNUM)
3661 /* Compute a (partial) cost for rtx X. Return true if the complete
3662 cost has been computed, and false if subexpressions should be
3663 scanned. In either case, *TOTAL contains the cost result. */
3664 /* Note that OUTER_CODE ought to be RTX_CODE, but that's
3665 not necessarily defined at this point. */
3666 DEFHOOK
3667 (rtx_costs,
3668 "This target hook describes the relative costs of RTL expressions.\n\
3670 The cost may depend on the precise form of the expression, which is\n\
3671 available for examination in @var{x}, and the fact that @var{x} appears\n\
3672 as operand @var{opno} of an expression with rtx code @var{outer_code}.\n\
3673 That is, the hook can assume that there is some rtx @var{y} such\n\
3674 that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that\n\
3675 either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or\n\
3676 (b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.\n\
3678 @var{mode} is @var{x}'s machine mode, or for cases like @code{const_int} that\n\
3679 do not have a mode, the mode in which @var{x} is used.\n\
3681 In implementing this hook, you can use the construct\n\
3682 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3683 instructions.\n\
3685 On entry to the hook, @code{*@var{total}} contains a default estimate\n\
3686 for the cost of the expression. The hook should modify this value as\n\
3687 necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}\n\
3688 for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus\n\
3689 operations, and @code{COSTS_N_INSNS (1)} for all other operations.\n\
3691 When optimizing for code size, i.e.@: when @code{speed} is\n\
3692 false, this target hook should be used to estimate the relative\n\
3693 size cost of an expression, again relative to @code{COSTS_N_INSNS}.\n\
3695 The hook returns true when all subexpressions of @var{x} have been\n\
3696 processed, and false when @code{rtx_cost} should recurse.",
3697 bool, (rtx x, machine_mode mode, int outer_code, int opno, int *total, bool speed),
3698 hook_bool_rtx_mode_int_int_intp_bool_false)
3700 /* Compute the cost of X, used as an address. Never called with
3701 invalid addresses. */
3702 DEFHOOK
3703 (address_cost,
3704 "This hook computes the cost of an addressing mode that contains\n\
3705 @var{address}. If not defined, the cost is computed from\n\
3706 the @var{address} expression and the @code{TARGET_RTX_COST} hook.\n\
3708 For most CISC machines, the default cost is a good approximation of the\n\
3709 true cost of the addressing mode. However, on RISC machines, all\n\
3710 instructions normally have the same length and execution time. Hence\n\
3711 all addresses will have equal costs.\n\
3713 In cases where more than one form of an address is known, the form with\n\
3714 the lowest cost will be used. If multiple forms have the same, lowest,\n\
3715 cost, the one that is the most complex will be used.\n\
3717 For example, suppose an address that is equal to the sum of a register\n\
3718 and a constant is used twice in the same basic block. When this macro\n\
3719 is not defined, the address will be computed in a register and memory\n\
3720 references will be indirect through that register. On machines where\n\
3721 the cost of the addressing mode containing the sum is no higher than\n\
3722 that of a simple indirect reference, this will produce an additional\n\
3723 instruction and possibly require an additional register. Proper\n\
3724 specification of this macro eliminates this overhead for such machines.\n\
3726 This hook is never called with an invalid address.\n\
3728 On machines where an address involving more than one register is as\n\
3729 cheap as an address computation involving only one register, defining\n\
3730 @code{TARGET_ADDRESS_COST} to reflect this can cause two registers to\n\
3731 be live over a region of code where only one would have been if\n\
3732 @code{TARGET_ADDRESS_COST} were not defined in that manner. This effect\n\
3733 should be considered in the definition of this macro. Equivalent costs\n\
3734 should probably only be given to addresses with different numbers of\n\
3735 registers on machines with lots of registers.",
3736 int, (rtx address, machine_mode mode, addr_space_t as, bool speed),
3737 default_address_cost)
3739 /* Compute a cost for INSN. */
3740 DEFHOOK
3741 (insn_cost,
3742 "This target hook describes the relative costs of RTL instructions.\n\
3744 In implementing this hook, you can use the construct\n\
3745 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3746 instructions.\n\
3748 When optimizing for code size, i.e.@: when @code{speed} is\n\
3749 false, this target hook should be used to estimate the relative\n\
3750 size cost of an expression, again relative to @code{COSTS_N_INSNS}.",
3751 int, (rtx_insn *insn, bool speed), NULL)
3753 /* Give a cost, in RTX Costs units, for an edge. Like BRANCH_COST, but with
3754 well defined units. */
3755 DEFHOOK
3756 (max_noce_ifcvt_seq_cost,
3757 "This hook returns a value in the same units as @code{TARGET_RTX_COSTS},\n\
3758 giving the maximum acceptable cost for a sequence generated by the RTL\n\
3759 if-conversion pass when conditional execution is not available.\n\
3760 The RTL if-conversion pass attempts to convert conditional operations\n\
3761 that would require a branch to a series of unconditional operations and\n\
3762 @code{mov@var{mode}cc} insns. This hook returns the maximum cost of the\n\
3763 unconditional instructions and the @code{mov@var{mode}cc} insns.\n\
3764 RTL if-conversion is cancelled if the cost of the converted sequence\n\
3765 is greater than the value returned by this hook.\n\
3767 @code{e} is the edge between the basic block containing the conditional\n\
3768 branch to the basic block which would be executed if the condition\n\
3769 were true.\n\
3771 The default implementation of this hook uses the\n\
3772 @code{max-rtl-if-conversion-[un]predictable} parameters if they are set,\n\
3773 and uses a multiple of @code{BRANCH_COST} otherwise.",
3774 unsigned int, (edge e),
3775 default_max_noce_ifcvt_seq_cost)
3777 /* Return true if the given instruction sequence is a good candidate
3778 as a replacement for the if-convertible sequence. */
3779 DEFHOOK
3780 (noce_conversion_profitable_p,
3781 "This hook returns true if the instruction sequence @code{seq} is a good\n\
3782 candidate as a replacement for the if-convertible sequence described in\n\
3783 @code{if_info}.",
3784 bool, (rtx_insn *seq, struct noce_if_info *if_info),
3785 default_noce_conversion_profitable_p)
3787 /* Permit speculative instructions in delay slots during delayed-branch
3788 scheduling. */
3789 DEFHOOK
3790 (no_speculation_in_delay_slots_p,
3791 "This predicate controls the use of the eager delay slot filler to disallow\n\
3792 speculatively executed instructions being placed in delay slots. Targets\n\
3793 such as certain MIPS architectures possess both branches with and without\n\
3794 delay slots. As the eager delay slot filler can decrease performance,\n\
3795 disabling it is beneficial when ordinary branches are available. Use of\n\
3796 delay slot branches filled using the basic filler is often still desirable\n\
3797 as the delay slot can hide a pipeline bubble.", bool, (void),
3798 hook_bool_void_false)
3800 /* Return where to allocate pseudo for a given hard register initial value. */
3801 DEFHOOK
3802 (allocate_initial_value,
3803 "\n\
3804 When the initial value of a hard register has been copied in a pseudo\n\
3805 register, it is often not necessary to actually allocate another register\n\
3806 to this pseudo register, because the original hard register or a stack slot\n\
3807 it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}\n\
3808 is called at the start of register allocation once for each hard register\n\
3809 that had its initial value copied by using\n\
3810 @code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.\n\
3811 Possible values are @code{NULL_RTX}, if you don't want\n\
3812 to do any special allocation, a @code{REG} rtx---that would typically be\n\
3813 the hard register itself, if it is known not to be clobbered---or a\n\
3814 @code{MEM}.\n\
3815 If you are returning a @code{MEM}, this is only a hint for the allocator;\n\
3816 it might decide to use another register anyways.\n\
3817 You may use @code{current_function_is_leaf} or \n\
3818 @code{REG_N_SETS} in the hook to determine if the hard\n\
3819 register in question will not be clobbered.\n\
3820 The default value of this hook is @code{NULL}, which disables any special\n\
3821 allocation.",
3822 rtx, (rtx hard_reg), NULL)
3824 /* Return nonzero if evaluating UNSPEC X might cause a trap.
3825 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
3826 DEFHOOK
3827 (unspec_may_trap_p,
3828 "This target hook returns nonzero if @var{x}, an @code{unspec} or\n\
3829 @code{unspec_volatile} operation, might cause a trap. Targets can use\n\
3830 this hook to enhance precision of analysis for @code{unspec} and\n\
3831 @code{unspec_volatile} operations. You may call @code{may_trap_p_1}\n\
3832 to analyze inner elements of @var{x} in which case @var{flags} should be\n\
3833 passed along.",
3834 int, (const_rtx x, unsigned flags),
3835 default_unspec_may_trap_p)
3837 /* Given a register, this hook should return a parallel of registers
3838 to represent where to find the register pieces. Define this hook
3839 if the register and its mode are represented in Dwarf in
3840 non-contiguous locations, or if the register should be
3841 represented in more than one register in Dwarf. Otherwise, this
3842 hook should return NULL_RTX. */
3843 DEFHOOK
3844 (dwarf_register_span,
3845 "Given a register, this hook should return a parallel of registers to\n\
3846 represent where to find the register pieces. Define this hook if the\n\
3847 register and its mode are represented in Dwarf in non-contiguous\n\
3848 locations, or if the register should be represented in more than one\n\
3849 register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.\n\
3850 If not defined, the default is to return @code{NULL_RTX}.",
3851 rtx, (rtx reg),
3852 hook_rtx_rtx_null)
3854 /* Given a register return the mode of the corresponding DWARF frame
3855 register. */
3856 DEFHOOK
3857 (dwarf_frame_reg_mode,
3858 "Given a register, this hook should return the mode which the\n\
3859 corresponding Dwarf frame register should have. This is normally\n\
3860 used to return a smaller mode than the raw mode to prevent call\n\
3861 clobbered parts of a register altering the frame register size",
3862 machine_mode, (int regno),
3863 default_dwarf_frame_reg_mode)
3865 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
3866 entries not corresponding directly to registers below
3867 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
3868 code, given the address of the table. */
3869 DEFHOOK
3870 (init_dwarf_reg_sizes_extra,
3871 "If some registers are represented in Dwarf-2 unwind information in\n\
3872 multiple pieces, define this hook to fill in information about the\n\
3873 sizes of those pieces in the table used by the unwinder at runtime.\n\
3874 It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after\n\
3875 filling in a single size corresponding to each hard register;\n\
3876 @var{address} is the address of the table.",
3877 void, (tree address),
3878 hook_void_tree)
3880 /* Fetch the fixed register(s) which hold condition codes, for
3881 targets where it makes sense to look for duplicate assignments to
3882 the condition codes. This should return true if there is such a
3883 register, false otherwise. The arguments should be set to the
3884 fixed register numbers. Up to two condition code registers are
3885 supported. If there is only one for this target, the int pointed
3886 at by the second argument should be set to -1. */
3887 DEFHOOK
3888 (fixed_condition_code_regs,
3889 "On targets which do not use @code{(cc0)}, and which use a hard\n\
3890 register rather than a pseudo-register to hold condition codes, the\n\
3891 regular CSE passes are often not able to identify cases in which the\n\
3892 hard register is set to a common value. Use this hook to enable a\n\
3893 small pass which optimizes such cases. This hook should return true\n\
3894 to enable this pass, and it should set the integers to which its\n\
3895 arguments point to the hard register numbers used for condition codes.\n\
3896 When there is only one such register, as is true on most systems, the\n\
3897 integer pointed to by @var{p2} should be set to\n\
3898 @code{INVALID_REGNUM}.\n\
3900 The default version of this hook returns false.",
3901 bool, (unsigned int *p1, unsigned int *p2),
3902 hook_bool_uintp_uintp_false)
3904 /* If two condition code modes are compatible, return a condition
3905 code mode which is compatible with both, such that a comparison
3906 done in the returned mode will work for both of the original
3907 modes. If the condition code modes are not compatible, return
3908 VOIDmode. */
3909 DEFHOOK
3910 (cc_modes_compatible,
3911 "On targets which use multiple condition code modes in class\n\
3912 @code{MODE_CC}, it is sometimes the case that a comparison can be\n\
3913 validly done in more than one mode. On such a system, define this\n\
3914 target hook to take two mode arguments and to return a mode in which\n\
3915 both comparisons may be validly done. If there is no such mode,\n\
3916 return @code{VOIDmode}.\n\
3918 The default version of this hook checks whether the modes are the\n\
3919 same. If they are, it returns that mode. If they are different, it\n\
3920 returns @code{VOIDmode}.",
3921 machine_mode, (machine_mode m1, machine_mode m2),
3922 default_cc_modes_compatible)
3924 /* Do machine-dependent code transformations. Called just before
3925 delayed-branch scheduling. */
3926 DEFHOOK
3927 (machine_dependent_reorg,
3928 "If non-null, this hook performs a target-specific pass over the\n\
3929 instruction stream. The compiler will run it at all optimization levels,\n\
3930 just before the point at which it normally does delayed-branch scheduling.\n\
3932 The exact purpose of the hook varies from target to target. Some use\n\
3933 it to do transformations that are necessary for correctness, such as\n\
3934 laying out in-function constant pools or avoiding hardware hazards.\n\
3935 Others use it as an opportunity to do some machine-dependent optimizations.\n\
3937 You need not implement the hook if it has nothing to do. The default\n\
3938 definition is null.",
3939 void, (void), NULL)
3941 /* Create the __builtin_va_list type. */
3942 DEFHOOK
3943 (build_builtin_va_list,
3944 "This hook returns a type node for @code{va_list} for the target.\n\
3945 The default version of the hook returns @code{void*}.",
3946 tree, (void),
3947 std_build_builtin_va_list)
3949 /* Enumerate the va list variants. */
3950 DEFHOOK
3951 (enum_va_list_p,
3952 "This target hook is used in function @code{c_common_nodes_and_builtins}\n\
3953 to iterate through the target specific builtin types for va_list. The\n\
3954 variable @var{idx} is used as iterator. @var{pname} has to be a pointer\n\
3955 to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed\n\
3956 variable.\n\
3957 The arguments @var{pname} and @var{ptree} are used to store the result of\n\
3958 this macro and are set to the name of the va_list builtin type and its\n\
3959 internal type.\n\
3960 If the return value of this macro is zero, then there is no more element.\n\
3961 Otherwise the @var{IDX} should be increased for the next call of this\n\
3962 macro to iterate through all types.",
3963 int, (int idx, const char **pname, tree *ptree),
3964 NULL)
3966 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
3967 DEFHOOK
3968 (fn_abi_va_list,
3969 "This hook returns the va_list type of the calling convention specified by\n\
3970 @var{fndecl}.\n\
3971 The default version of this hook returns @code{va_list_type_node}.",
3972 tree, (tree fndecl),
3973 std_fn_abi_va_list)
3975 /* Get the __builtin_va_list type dependent on input type. */
3976 DEFHOOK
3977 (canonical_va_list_type,
3978 "This hook returns the va_list type of the calling convention specified by the\n\
3979 type of @var{type}. If @var{type} is not a valid va_list type, it returns\n\
3980 @code{NULL_TREE}.",
3981 tree, (tree type),
3982 std_canonical_va_list_type)
3984 /* ??? Documenting this hook requires a GFDL license grant. */
3985 DEFHOOK_UNDOC
3986 (expand_builtin_va_start,
3987 "Expand the @code{__builtin_va_start} builtin.",
3988 void, (tree valist, rtx nextarg), NULL)
3990 /* Gimplifies a VA_ARG_EXPR. */
3991 DEFHOOK
3992 (gimplify_va_arg_expr,
3993 "This hook performs target-specific gimplification of\n\
3994 @code{VA_ARG_EXPR}. The first two parameters correspond to the\n\
3995 arguments to @code{va_arg}; the latter two are as in\n\
3996 @code{gimplify.c:gimplify_expr}.",
3997 tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
3998 std_gimplify_va_arg_expr)
4000 /* Validity-checking routines for PCH files, target-specific.
4001 get_pch_validity returns a pointer to the data to be stored,
4002 and stores the size in its argument. pch_valid_p gets the same
4003 information back and returns NULL if the PCH is valid,
4004 or an error message if not. */
4005 DEFHOOK
4006 (get_pch_validity,
4007 "This hook returns a pointer to the data needed by\n\
4008 @code{TARGET_PCH_VALID_P} and sets\n\
4009 @samp{*@var{sz}} to the size of the data in bytes.",
4010 void *, (size_t *sz),
4011 default_get_pch_validity)
4013 DEFHOOK
4014 (pch_valid_p,
4015 "This hook checks whether the options used to create a PCH file are\n\
4016 compatible with the current settings. It returns @code{NULL}\n\
4017 if so and a suitable error message if not. Error messages will\n\
4018 be presented to the user and must be localized using @samp{_(@var{msg})}.\n\
4020 @var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}\n\
4021 when the PCH file was created and @var{sz} is the size of that data in bytes.\n\
4022 It's safe to assume that the data was created by the same version of the\n\
4023 compiler, so no format checking is needed.\n\
4025 The default definition of @code{default_pch_valid_p} should be\n\
4026 suitable for most targets.",
4027 const char *, (const void *data, size_t sz),
4028 default_pch_valid_p)
4030 DEFHOOK
4031 (prepare_pch_save,
4032 "Called before writing out a PCH file. If the target has some\n\
4033 garbage-collected data that needs to be in a particular state on PCH loads,\n\
4034 it can use this hook to enforce that state. Very few targets need\n\
4035 to do anything here.",
4036 void, (void),
4037 hook_void_void)
4039 /* If nonnull, this function checks whether a PCH file with the
4040 given set of target flags can be used. It returns NULL if so,
4041 otherwise it returns an error message. */
4042 DEFHOOK
4043 (check_pch_target_flags,
4044 "If this hook is nonnull, the default implementation of\n\
4045 @code{TARGET_PCH_VALID_P} will use it to check for compatible values\n\
4046 of @code{target_flags}. @var{pch_flags} specifies the value that\n\
4047 @code{target_flags} had when the PCH file was created. The return\n\
4048 value is the same as for @code{TARGET_PCH_VALID_P}.",
4049 const char *, (int pch_flags), NULL)
4051 /* True if the compiler should give an enum type only as many
4052 bytes as it takes to represent the range of possible values of
4053 that type. */
4054 DEFHOOK
4055 (default_short_enums,
4056 "This target hook should return true if the compiler should give an\n\
4057 @code{enum} type only as many bytes as it takes to represent the range\n\
4058 of possible values of that type. It should return false if all\n\
4059 @code{enum} types should be allocated like @code{int}.\n\
4061 The default is to return false.",
4062 bool, (void),
4063 hook_bool_void_false)
4065 /* This target hook returns an rtx that is used to store the address
4066 of the current frame into the built-in setjmp buffer. */
4067 DEFHOOK
4068 (builtin_setjmp_frame_value,
4069 "This target hook should return an rtx that is used to store\n\
4070 the address of the current frame into the built in @code{setjmp} buffer.\n\
4071 The default value, @code{virtual_stack_vars_rtx}, is correct for most\n\
4072 machines. One reason you may need to define this target hook is if\n\
4073 @code{hard_frame_pointer_rtx} is the appropriate value on your machine.",
4074 rtx, (void),
4075 default_builtin_setjmp_frame_value)
4077 /* This target hook should manipulate the outputs, inputs, constraints,
4078 and clobbers the port wishes for pre-processing the asm. */
4079 DEFHOOK
4080 (md_asm_adjust,
4081 "This target hook may add @dfn{clobbers} to @var{clobbers} and\n\
4082 @var{clobbered_regs} for any hard regs the port wishes to automatically\n\
4083 clobber for an asm. The @var{outputs} and @var{inputs} may be inspected\n\
4084 to avoid clobbering a register that is already used by the asm.\n\
4086 It may modify the @var{outputs}, @var{inputs}, and @var{constraints}\n\
4087 as necessary for other pre-processing. In this case the return value is\n\
4088 a sequence of insns to emit after the asm.",
4089 rtx_insn *,
4090 (vec<rtx>& outputs, vec<rtx>& inputs, vec<const char *>& constraints,
4091 vec<rtx>& clobbers, HARD_REG_SET& clobbered_regs),
4092 NULL)
4094 /* This target hook allows the backend to specify a calling convention
4095 in the debug information. This function actually returns an
4096 enum dwarf_calling_convention, but because of forward declarations
4097 and not wanting to include dwarf2.h everywhere target.h is included
4098 the function is being declared as an int. */
4099 DEFHOOK
4100 (dwarf_calling_convention,
4101 "Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to\n\
4102 be emitted for each function. Instead of an integer return the enum\n\
4103 value for the @code{DW_CC_} tag.",
4104 int, (const_tree function),
4105 hook_int_const_tree_0)
4107 /* This target hook allows the backend to emit frame-related insns that
4108 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
4109 engine will invoke it on insns of the form
4110 (set (reg) (unspec [...] UNSPEC_INDEX))
4112 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
4113 to let the backend emit the call frame instructions. */
4114 DEFHOOK
4115 (dwarf_handle_frame_unspec,
4116 "This target hook allows the backend to emit frame-related insns that\n\
4117 contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging\n\
4118 info engine will invoke it on insns of the form\n\
4119 @smallexample\n\
4120 (set (reg) (unspec [@dots{}] UNSPEC_INDEX))\n\
4121 @end smallexample\n\
4122 and\n\
4123 @smallexample\n\
4124 (set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).\n\
4125 @end smallexample\n\
4126 to let the backend emit the call frame instructions. @var{label} is\n\
4127 the CFI label attached to the insn, @var{pattern} is the pattern of\n\
4128 the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.",
4129 void, (const char *label, rtx pattern, int index), NULL)
4131 /* ??? Documenting this hook requires a GFDL license grant. */
4132 DEFHOOK_UNDOC
4133 (stdarg_optimize_hook,
4134 "Perform architecture specific checking of statements gimplified\
4135 from @code{VA_ARG_EXPR}. @var{stmt} is the statement. Returns true if\
4136 the statement doesn't need to be checked for @code{va_list} references.",
4137 bool, (struct stdarg_info *ai, const gimple *stmt), NULL)
4139 /* This target hook allows the operating system to override the DECL
4140 that represents the external variable that contains the stack
4141 protection guard variable. The type of this DECL is ptr_type_node. */
4142 DEFHOOK
4143 (stack_protect_guard,
4144 "This hook returns a @code{DECL} node for the external variable to use\n\
4145 for the stack protection guard. This variable is initialized by the\n\
4146 runtime to some random value and is used to initialize the guard value\n\
4147 that is placed at the top of the local stack frame. The type of this\n\
4148 variable must be @code{ptr_type_node}.\n\
4150 The default version of this hook creates a variable called\n\
4151 @samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.",
4152 tree, (void),
4153 default_stack_protect_guard)
4155 /* This target hook allows the operating system to override the CALL_EXPR
4156 that is invoked when a check vs the guard variable fails. */
4157 DEFHOOK
4158 (stack_protect_fail,
4159 "This hook returns a @code{CALL_EXPR} that alerts the runtime that the\n\
4160 stack protect guard variable has been modified. This expression should\n\
4161 involve a call to a @code{noreturn} function.\n\
4163 The default version of this hook invokes a function called\n\
4164 @samp{__stack_chk_fail}, taking no arguments. This function is\n\
4165 normally defined in @file{libgcc2.c}.",
4166 tree, (void),
4167 default_external_stack_protect_fail)
4169 /* This target hook allows the operating system to disable the default stack
4170 protector runtime support. */
4171 DEFHOOK
4172 (stack_protect_runtime_enabled_p,
4173 "Returns true if the target wants GCC's default stack protect runtime support,\
4174 otherwise return false. The default implementation always returns true.",
4175 bool, (void),
4176 hook_bool_void_true)
4178 DEFHOOK
4179 (can_use_doloop_p,
4180 "Return true if it is possible to use low-overhead loops (@code{doloop_end}\n\
4181 and @code{doloop_begin}) for a particular loop. @var{iterations} gives the\n\
4182 exact number of iterations, or 0 if not known. @var{iterations_max} gives\n\
4183 the maximum number of iterations, or 0 if not known. @var{loop_depth} is\n\
4184 the nesting depth of the loop, with 1 for innermost loops, 2 for loops that\n\
4185 contain innermost loops, and so on. @var{entered_at_top} is true if the\n\
4186 loop is only entered from the top.\n\
4188 This hook is only used if @code{doloop_end} is available. The default\n\
4189 implementation returns true. You can use @code{can_use_doloop_if_innermost}\n\
4190 if the loop must be the innermost, and if there are no other restrictions.",
4191 bool, (const widest_int &iterations, const widest_int &iterations_max,
4192 unsigned int loop_depth, bool entered_at_top),
4193 hook_bool_wint_wint_uint_bool_true)
4195 /* Returns NULL if target supports the insn within a doloop block,
4196 otherwise it returns an error message. */
4197 DEFHOOK
4198 (invalid_within_doloop,
4199 "\n\
4200 Take an instruction in @var{insn} and return NULL if it is valid within a\n\
4201 low-overhead loop, otherwise return a string explaining why doloop\n\
4202 could not be applied.\n\
4204 Many targets use special registers for low-overhead looping. For any\n\
4205 instruction that clobbers these this function should return a string indicating\n\
4206 the reason why the doloop could not be applied.\n\
4207 By default, the RTL loop optimizer does not use a present doloop pattern for\n\
4208 loops containing function calls or branch on table instructions.",
4209 const char *, (const rtx_insn *insn),
4210 default_invalid_within_doloop)
4212 /* Returns true for a legitimate combined insn. */
4213 DEFHOOK
4214 (legitimate_combined_insn,
4215 "Take an instruction in @var{insn} and return @code{false} if the instruction\
4216 is not appropriate as a combination of two or more instructions. The\
4217 default is to accept all instructions.",
4218 bool, (rtx_insn *insn),
4219 hook_bool_rtx_insn_true)
4221 DEFHOOK
4222 (valid_dllimport_attribute_p,
4223 "@var{decl} is a variable or function with @code{__attribute__((dllimport))}\
4224 specified. Use this hook if the target needs to add extra validation\
4225 checks to @code{handle_dll_attribute}.",
4226 bool, (const_tree decl),
4227 hook_bool_const_tree_true)
4229 /* If non-zero, align constant anchors in CSE to a multiple of this
4230 value. */
4231 DEFHOOKPOD
4232 (const_anchor,
4233 "On some architectures it can take multiple instructions to synthesize\n\
4234 a constant. If there is another constant already in a register that\n\
4235 is close enough in value then it is preferable that the new constant\n\
4236 is computed from this register using immediate addition or\n\
4237 subtraction. We accomplish this through CSE. Besides the value of\n\
4238 the constant we also add a lower and an upper constant anchor to the\n\
4239 available expressions. These are then queried when encountering new\n\
4240 constants. The anchors are computed by rounding the constant up and\n\
4241 down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.\n\
4242 @code{TARGET_CONST_ANCHOR} should be the maximum positive value\n\
4243 accepted by immediate-add plus one. We currently assume that the\n\
4244 value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on\n\
4245 MIPS, where add-immediate takes a 16-bit signed value,\n\
4246 @code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value\n\
4247 is zero, which disables this optimization.",
4248 unsigned HOST_WIDE_INT, 0)
4250 /* Defines, which target-dependent bits (upper 16) are used by port */
4251 DEFHOOK
4252 (memmodel_check,
4253 "Validate target specific memory model mask bits. When NULL no target specific\n\
4254 memory model bits are allowed.",
4255 unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)
4257 /* Defines an offset bitwise ored into shifted address to get corresponding
4258 Address Sanitizer shadow address, or -1 if Address Sanitizer is not
4259 supported by the target. */
4260 DEFHOOK
4261 (asan_shadow_offset,
4262 "Return the offset bitwise ored into shifted address to get corresponding\n\
4263 Address Sanitizer shadow memory address. NULL if Address Sanitizer is not\n\
4264 supported by the target.",
4265 unsigned HOST_WIDE_INT, (void),
4266 NULL)
4268 /* Functions relating to calls - argument passing, returns, etc. */
4269 /* Members of struct call have no special macro prefix. */
4270 HOOK_VECTOR (TARGET_CALLS, calls)
4272 DEFHOOK
4273 (promote_function_mode,
4274 "Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or\n\
4275 function return values. The target hook should return the new mode\n\
4276 and possibly change @code{*@var{punsignedp}} if the promotion should\n\
4277 change signedness. This function is called only for scalar @emph{or\n\
4278 pointer} types.\n\
4280 @var{for_return} allows to distinguish the promotion of arguments and\n\
4281 return values. If it is @code{1}, a return value is being promoted and\n\
4282 @code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.\n\
4283 If it is @code{2}, the returned mode should be that of the register in\n\
4284 which an incoming parameter is copied, or the outgoing result is computed;\n\
4285 then the hook should return the same mode as @code{promote_mode}, though\n\
4286 the signedness may be different.\n\
4288 @var{type} can be NULL when promoting function arguments of libcalls.\n\
4290 The default is to not promote arguments and return values. You can\n\
4291 also define the hook to @code{default_promote_function_mode_always_promote}\n\
4292 if you would like to apply the same rules given by @code{PROMOTE_MODE}.",
4293 machine_mode, (const_tree type, machine_mode mode, int *punsignedp,
4294 const_tree funtype, int for_return),
4295 default_promote_function_mode)
4297 DEFHOOK
4298 (promote_prototypes,
4299 "This target hook returns @code{true} if an argument declared in a\n\
4300 prototype as an integral type smaller than @code{int} should actually be\n\
4301 passed as an @code{int}. In addition to avoiding errors in certain\n\
4302 cases of mismatch, it also makes for better code on certain machines.\n\
4303 The default is to not promote prototypes.",
4304 bool, (const_tree fntype),
4305 hook_bool_const_tree_false)
4307 DEFHOOK
4308 (struct_value_rtx,
4309 "This target hook should return the location of the structure value\n\
4310 address (normally a @code{mem} or @code{reg}), or 0 if the address is\n\
4311 passed as an ``invisible'' first argument. Note that @var{fndecl} may\n\
4312 be @code{NULL}, for libcalls. You do not need to define this target\n\
4313 hook if the address is always passed as an ``invisible'' first\n\
4314 argument.\n\
4316 On some architectures the place where the structure value address\n\
4317 is found by the called function is not the same place that the\n\
4318 caller put it. This can be due to register windows, or it could\n\
4319 be because the function prologue moves it to a different place.\n\
4320 @var{incoming} is @code{1} or @code{2} when the location is needed in\n\
4321 the context of the called function, and @code{0} in the context of\n\
4322 the caller.\n\
4324 If @var{incoming} is nonzero and the address is to be found on the\n\
4325 stack, return a @code{mem} which refers to the frame pointer. If\n\
4326 @var{incoming} is @code{2}, the result is being used to fetch the\n\
4327 structure value address at the beginning of a function. If you need\n\
4328 to emit adjusting code, you should do it at this point.",
4329 rtx, (tree fndecl, int incoming),
4330 hook_rtx_tree_int_null)
4332 DEFHOOKPOD
4333 (omit_struct_return_reg,
4334 "Normally, when a function returns a structure by memory, the address\n\
4335 is passed as an invisible pointer argument, but the compiler also\n\
4336 arranges to return the address from the function like it would a normal\n\
4337 pointer return value. Define this to true if that behavior is\n\
4338 undesirable on your target.",
4339 bool, false)
4341 DEFHOOK
4342 (return_in_memory,
4343 "This target hook should return a nonzero value to say to return the\n\
4344 function value in memory, just as large structures are always returned.\n\
4345 Here @var{type} will be the data type of the value, and @var{fntype}\n\
4346 will be the type of the function doing the returning, or @code{NULL} for\n\
4347 libcalls.\n\
4349 Note that values of mode @code{BLKmode} must be explicitly handled\n\
4350 by this function. Also, the option @option{-fpcc-struct-return}\n\
4351 takes effect regardless of this macro. On most systems, it is\n\
4352 possible to leave the hook undefined; this causes a default\n\
4353 definition to be used, whose value is the constant 1 for @code{BLKmode}\n\
4354 values, and 0 otherwise.\n\
4356 Do not use this hook to indicate that structures and unions should always\n\
4357 be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}\n\
4358 to indicate this.",
4359 bool, (const_tree type, const_tree fntype),
4360 default_return_in_memory)
4362 DEFHOOK
4363 (return_in_msb,
4364 "This hook should return true if values of type @var{type} are returned\n\
4365 at the most significant end of a register (in other words, if they are\n\
4366 padded at the least significant end). You can assume that @var{type}\n\
4367 is returned in a register; the caller is required to check this.\n\
4369 Note that the register provided by @code{TARGET_FUNCTION_VALUE} must\n\
4370 be able to hold the complete return value. For example, if a 1-, 2-\n\
4371 or 3-byte structure is returned at the most significant end of a\n\
4372 4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an\n\
4373 @code{SImode} rtx.",
4374 bool, (const_tree type),
4375 hook_bool_const_tree_false)
4377 /* Return true if a parameter must be passed by reference. TYPE may
4378 be null if this is a libcall. CA may be null if this query is
4379 from __builtin_va_arg. */
4380 DEFHOOK
4381 (pass_by_reference,
4382 "This target hook should return @code{true} if an argument at the\n\
4383 position indicated by @var{cum} should be passed by reference. This\n\
4384 predicate is queried after target independent reasons for being\n\
4385 passed by reference, such as @code{TREE_ADDRESSABLE (type)}.\n\
4387 If the hook returns true, a copy of that argument is made in memory and a\n\
4388 pointer to the argument is passed instead of the argument itself.\n\
4389 The pointer is passed in whatever way is appropriate for passing a pointer\n\
4390 to that type.",
4391 bool,
4392 (cumulative_args_t cum, machine_mode mode, const_tree type, bool named),
4393 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
4395 DEFHOOK
4396 (expand_builtin_saveregs,
4397 "If defined, this hook produces the machine-specific code for a call to\n\
4398 @code{__builtin_saveregs}. This code will be moved to the very\n\
4399 beginning of the function, before any parameter access are made. The\n\
4400 return value of this function should be an RTX that contains the value\n\
4401 to use as the return of @code{__builtin_saveregs}.",
4402 rtx, (void),
4403 default_expand_builtin_saveregs)
4405 /* Returns pretend_argument_size. */
4406 DEFHOOK
4407 (setup_incoming_varargs,
4408 "This target hook offers an alternative to using\n\
4409 @code{__builtin_saveregs} and defining the hook\n\
4410 @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous\n\
4411 register arguments into the stack so that all the arguments appear to\n\
4412 have been passed consecutively on the stack. Once this is done, you can\n\
4413 use the standard implementation of varargs that works for machines that\n\
4414 pass all their arguments on the stack.\n\
4416 The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data\n\
4417 structure, containing the values that are obtained after processing the\n\
4418 named arguments. The arguments @var{mode} and @var{type} describe the\n\
4419 last named argument---its machine mode and its data type as a tree node.\n\
4421 The target hook should do two things: first, push onto the stack all the\n\
4422 argument registers @emph{not} used for the named arguments, and second,\n\
4423 store the size of the data thus pushed into the @code{int}-valued\n\
4424 variable pointed to by @var{pretend_args_size}. The value that you\n\
4425 store here will serve as additional offset for setting up the stack\n\
4426 frame.\n\
4428 Because you must generate code to push the anonymous arguments at\n\
4429 compile time without knowing their data types,\n\
4430 @code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that\n\
4431 have just a single category of argument register and use it uniformly\n\
4432 for all data types.\n\
4434 If the argument @var{second_time} is nonzero, it means that the\n\
4435 arguments of the function are being analyzed for the second time. This\n\
4436 happens for an inline function, which is not actually compiled until the\n\
4437 end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should\n\
4438 not generate any instructions in this case.",
4439 void, (cumulative_args_t args_so_far, machine_mode mode, tree type,
4440 int *pretend_args_size, int second_time),
4441 default_setup_incoming_varargs)
4443 DEFHOOK
4444 (load_bounds_for_arg,
4445 "This hook is used by expand pass to emit insn to load bounds of\n\
4446 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4447 bounds of @var{arg} are not passed in register. If @var{slot} is a\n\
4448 memory, then bounds are loaded as for regular pointer loaded from\n\
4449 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4450 constant holding number of the target dependent special slot which\n\
4451 should be used to obtain bounds. Hook returns RTX holding loaded bounds.",
4452 rtx, (rtx slot, rtx arg, rtx slot_no),
4453 default_load_bounds_for_arg)
4455 DEFHOOK
4456 (store_bounds_for_arg,
4457 "This hook is used by expand pass to emit insns to store @var{bounds} of\n\
4458 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4459 @var{bounds} of @var{arg} are not passed in register. If @var{slot} is a\n\
4460 memory, then @var{bounds} are stored as for regular pointer stored in\n\
4461 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4462 constant holding number of the target dependent special slot which\n\
4463 should be used to store @var{bounds}.",
4464 void, (rtx arg, rtx slot, rtx bounds, rtx slot_no),
4465 default_store_bounds_for_arg)
4467 DEFHOOK
4468 (load_returned_bounds,
4469 "This hook is used by expand pass to emit insn to load bounds\n\
4470 returned by function call in @var{slot}. Hook returns RTX holding\n\
4471 loaded bounds.",
4472 rtx, (rtx slot),
4473 default_load_returned_bounds)
4475 DEFHOOK
4476 (store_returned_bounds,
4477 "This hook is used by expand pass to emit insn to store @var{bounds}\n\
4478 returned by function call into @var{slot}.",
4479 void, (rtx slot, rtx bounds),
4480 default_store_returned_bounds)
4482 DEFHOOK
4483 (setup_incoming_vararg_bounds,
4484 "Use it to store bounds for anonymous register arguments stored\n\
4485 into the stack. Arguments meaning is similar to\n\
4486 @code{TARGET_SETUP_INCOMING_VARARGS}.",
4487 void, (cumulative_args_t args_so_far, machine_mode mode, tree type,
4488 int *pretend_args_size, int second_time),
4489 default_setup_incoming_vararg_bounds)
4491 DEFHOOK
4492 (call_args,
4493 "While generating RTL for a function call, this target hook is invoked once\n\
4494 for each argument passed to the function, either a register returned by\n\
4495 @code{TARGET_FUNCTION_ARG} or a memory location. It is called just\n\
4496 before the point where argument registers are stored. The type of the\n\
4497 function to be called is also passed as the second argument; it is\n\
4498 @code{NULL_TREE} for libcalls. The @code{TARGET_END_CALL_ARGS} hook is\n\
4499 invoked just after the code to copy the return reg has been emitted.\n\
4500 This functionality can be used to perform special setup of call argument\n\
4501 registers if a target needs it.\n\
4502 For functions without arguments, the hook is called once with @code{pc_rtx}\n\
4503 passed instead of an argument register.\n\
4504 Most ports do not need to implement anything for this hook.",
4505 void, (rtx, tree),
4506 hook_void_rtx_tree)
4508 DEFHOOK
4509 (end_call_args,
4510 "This target hook is invoked while generating RTL for a function call,\n\
4511 just after the point where the return reg is copied into a pseudo. It\n\
4512 signals that all the call argument and return registers for the just\n\
4513 emitted call are now no longer in use.\n\
4514 Most ports do not need to implement anything for this hook.",
4515 void, (void),
4516 hook_void_void)
4518 DEFHOOK
4519 (strict_argument_naming,
4520 "Define this hook to return @code{true} if the location where a function\n\
4521 argument is passed depends on whether or not it is a named argument.\n\
4523 This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}\n\
4524 is set for varargs and stdarg functions. If this hook returns\n\
4525 @code{true}, the @var{named} argument is always true for named\n\
4526 arguments, and false for unnamed arguments. If it returns @code{false},\n\
4527 but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},\n\
4528 then all arguments are treated as named. Otherwise, all named arguments\n\
4529 except the last are treated as named.\n\
4531 You need not define this hook if it always returns @code{false}.",
4532 bool, (cumulative_args_t ca),
4533 hook_bool_CUMULATIVE_ARGS_false)
4535 /* Returns true if we should use
4536 targetm.calls.setup_incoming_varargs() and/or
4537 targetm.calls.strict_argument_naming(). */
4538 DEFHOOK
4539 (pretend_outgoing_varargs_named,
4540 "If you need to conditionally change ABIs so that one works with\n\
4541 @code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither\n\
4542 @code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was\n\
4543 defined, then define this hook to return @code{true} if\n\
4544 @code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.\n\
4545 Otherwise, you should not define this hook.",
4546 bool, (cumulative_args_t ca),
4547 default_pretend_outgoing_varargs_named)
4549 /* Given a complex type T, return true if a parameter of type T
4550 should be passed as two scalars. */
4551 DEFHOOK
4552 (split_complex_arg,
4553 "This hook should return true if parameter of type @var{type} are passed\n\
4554 as two scalar parameters. By default, GCC will attempt to pack complex\n\
4555 arguments into the target's word size. Some ABIs require complex arguments\n\
4556 to be split and treated as their individual components. For example, on\n\
4557 AIX64, complex floats should be passed in a pair of floating point\n\
4558 registers, even though a complex float would fit in one 64-bit floating\n\
4559 point register.\n\
4561 The default value of this hook is @code{NULL}, which is treated as always\n\
4562 false.",
4563 bool, (const_tree type), NULL)
4565 /* Return true if type T, mode MODE, may not be passed in registers,
4566 but must be passed on the stack. */
4567 /* ??? This predicate should be applied strictly after pass-by-reference.
4568 Need audit to verify that this is the case. */
4569 DEFHOOK
4570 (must_pass_in_stack,
4571 "This target hook should return @code{true} if we should not pass @var{type}\n\
4572 solely in registers. The file @file{expr.h} defines a\n\
4573 definition that is usually appropriate, refer to @file{expr.h} for additional\n\
4574 documentation.",
4575 bool, (machine_mode mode, const_tree type),
4576 must_pass_in_stack_var_size_or_pad)
4578 /* Return true if type TYPE, mode MODE, which is passed by reference,
4579 should have the object copy generated by the callee rather than
4580 the caller. It is never called for TYPE requiring constructors. */
4581 DEFHOOK
4582 (callee_copies,
4583 "The function argument described by the parameters to this hook is\n\
4584 known to be passed by reference. The hook should return true if the\n\
4585 function argument should be copied by the callee instead of copied\n\
4586 by the caller.\n\
4588 For any argument for which the hook returns true, if it can be\n\
4589 determined that the argument is not modified, then a copy need\n\
4590 not be generated.\n\
4592 The default version of this hook always returns false.",
4593 bool,
4594 (cumulative_args_t cum, machine_mode mode, const_tree type, bool named),
4595 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
4597 /* Return zero for arguments passed entirely on the stack or entirely
4598 in registers. If passed in both, return the number of bytes passed
4599 in registers; the balance is therefore passed on the stack. */
4600 DEFHOOK
4601 (arg_partial_bytes,
4602 "This target hook returns the number of bytes at the beginning of an\n\
4603 argument that must be put in registers. The value must be zero for\n\
4604 arguments that are passed entirely in registers or that are entirely\n\
4605 pushed on the stack.\n\
4607 On some machines, certain arguments must be passed partially in\n\
4608 registers and partially in memory. On these machines, typically the\n\
4609 first few words of arguments are passed in registers, and the rest\n\
4610 on the stack. If a multi-word argument (a @code{double} or a\n\
4611 structure) crosses that boundary, its first few words must be passed\n\
4612 in registers and the rest must be pushed. This macro tells the\n\
4613 compiler when this occurs, and how many bytes should go in registers.\n\
4615 @code{TARGET_FUNCTION_ARG} for these arguments should return the first\n\
4616 register to be used by the caller for this argument; likewise\n\
4617 @code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.",
4618 int, (cumulative_args_t cum, machine_mode mode, tree type, bool named),
4619 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0)
4621 /* Update the state in CA to advance past an argument in the
4622 argument list. The values MODE, TYPE, and NAMED describe that
4623 argument. */
4624 DEFHOOK
4625 (function_arg_advance,
4626 "This hook updates the summarizer variable pointed to by @var{ca} to\n\
4627 advance past an argument in the argument list. The values @var{mode},\n\
4628 @var{type} and @var{named} describe that argument. Once this is done,\n\
4629 the variable @var{cum} is suitable for analyzing the @emph{following}\n\
4630 argument with @code{TARGET_FUNCTION_ARG}, etc.\n\
4632 This hook need not do anything if the argument in question was passed\n\
4633 on the stack. The compiler knows how to track the amount of stack space\n\
4634 used for arguments without any special help.",
4635 void,
4636 (cumulative_args_t ca, machine_mode mode, const_tree type, bool named),
4637 default_function_arg_advance)
4639 DEFHOOK
4640 (function_arg_offset,
4641 "This hook returns the number of bytes to add to the offset of an\n\
4642 argument of type @var{type} and mode @var{mode} when passed in memory.\n\
4643 This is needed for the SPU, which passes @code{char} and @code{short}\n\
4644 arguments in the preferred slot that is in the middle of the quad word\n\
4645 instead of starting at the top. The default implementation returns 0.",
4646 HOST_WIDE_INT, (machine_mode mode, const_tree type),
4647 default_function_arg_offset)
4649 DEFHOOK
4650 (function_arg_padding,
4651 "This hook determines whether, and in which direction, to pad out\n\
4652 an argument of mode @var{mode} and type @var{type}. It returns\n\
4653 @code{PAD_UPWARD} to insert padding above the argument, @code{PAD_DOWNWARD}\n\
4654 to insert padding below the argument, or @code{PAD_NONE} to inhibit padding.\n\
4656 The @emph{amount} of padding is not controlled by this hook, but by\n\
4657 @code{TARGET_FUNCTION_ARG_ROUND_BOUNDARY}. It is always just enough\n\
4658 to reach the next multiple of that boundary.\n\
4660 This hook has a default definition that is right for most systems.\n\
4661 For little-endian machines, the default is to pad upward. For\n\
4662 big-endian machines, the default is to pad downward for an argument of\n\
4663 constant size shorter than an @code{int}, and upward otherwise.",
4664 pad_direction, (machine_mode mode, const_tree type),
4665 default_function_arg_padding)
4667 /* Return zero if the argument described by the state of CA should
4668 be placed on a stack, or a hard register in which to store the
4669 argument. The values MODE, TYPE, and NAMED describe that
4670 argument. */
4671 DEFHOOK
4672 (function_arg,
4673 "Return an RTX indicating whether a function argument is passed in a\n\
4674 register and if so, which register.\n\
4676 The arguments are @var{ca}, which summarizes all the previous\n\
4677 arguments; @var{mode}, the machine mode of the argument; @var{type},\n\
4678 the data type of the argument as a tree node or 0 if that is not known\n\
4679 (which happens for C support library functions); and @var{named},\n\
4680 which is @code{true} for an ordinary argument and @code{false} for\n\
4681 nameless arguments that correspond to @samp{@dots{}} in the called\n\
4682 function's prototype. @var{type} can be an incomplete type if a\n\
4683 syntax error has previously occurred.\n\
4685 The return value is usually either a @code{reg} RTX for the hard\n\
4686 register in which to pass the argument, or zero to pass the argument\n\
4687 on the stack.\n\
4689 The return value can be a @code{const_int} which means argument is\n\
4690 passed in a target specific slot with specified number. Target hooks\n\
4691 should be used to store or load argument in such case. See\n\
4692 @code{TARGET_STORE_BOUNDS_FOR_ARG} and @code{TARGET_LOAD_BOUNDS_FOR_ARG}\n\
4693 for more information.\n\
4695 The value of the expression can also be a @code{parallel} RTX@. This is\n\
4696 used when an argument is passed in multiple locations. The mode of the\n\
4697 @code{parallel} should be the mode of the entire argument. The\n\
4698 @code{parallel} holds any number of @code{expr_list} pairs; each one\n\
4699 describes where part of the argument is passed. In each\n\
4700 @code{expr_list} the first operand must be a @code{reg} RTX for the hard\n\
4701 register in which to pass this part of the argument, and the mode of the\n\
4702 register RTX indicates how large this part of the argument is. The\n\
4703 second operand of the @code{expr_list} is a @code{const_int} which gives\n\
4704 the offset in bytes into the entire argument of where this part starts.\n\
4705 As a special exception the first @code{expr_list} in the @code{parallel}\n\
4706 RTX may have a first operand of zero. This indicates that the entire\n\
4707 argument is also stored on the stack.\n\
4709 The last time this hook is called, it is called with @code{MODE ==\n\
4710 VOIDmode}, and its result is passed to the @code{call} or @code{call_value}\n\
4711 pattern as operands 2 and 3 respectively.\n\
4713 @cindex @file{stdarg.h} and register arguments\n\
4714 The usual way to make the ISO library @file{stdarg.h} work on a\n\
4715 machine where some arguments are usually passed in registers, is to\n\
4716 cause nameless arguments to be passed on the stack instead. This is\n\
4717 done by making @code{TARGET_FUNCTION_ARG} return 0 whenever\n\
4718 @var{named} is @code{false}.\n\
4720 @cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}\n\
4721 @cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}\n\
4722 You may use the hook @code{targetm.calls.must_pass_in_stack}\n\
4723 in the definition of this macro to determine if this argument is of a\n\
4724 type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}\n\
4725 is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an\n\
4726 argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is\n\
4727 defined, the argument will be computed in the stack and then loaded into\n\
4728 a register.",
4729 rtx, (cumulative_args_t ca, machine_mode mode, const_tree type,
4730 bool named),
4731 default_function_arg)
4733 DEFHOOK
4734 (function_incoming_arg,
4735 "Define this hook if the caller and callee on the target have different\n\
4736 views of where arguments are passed. Also define this hook if there are\n\
4737 functions that are never directly called, but are invoked by the hardware\n\
4738 and which have nonstandard calling conventions.\n\
4740 In this case @code{TARGET_FUNCTION_ARG} computes the register in\n\
4741 which the caller passes the value, and\n\
4742 @code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar\n\
4743 fashion to tell the function being called where the arguments will\n\
4744 arrive.\n\
4746 @code{TARGET_FUNCTION_INCOMING_ARG} can also return arbitrary address\n\
4747 computation using hard register, which can be forced into a register,\n\
4748 so that it can be used to pass special arguments.\n\
4750 If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,\n\
4751 @code{TARGET_FUNCTION_ARG} serves both purposes.",
4752 rtx, (cumulative_args_t ca, machine_mode mode, const_tree type,
4753 bool named),
4754 default_function_incoming_arg)
4756 DEFHOOK
4757 (function_arg_boundary,
4758 "This hook returns the alignment boundary, in bits, of an argument\n\
4759 with the specified mode and type. The default hook returns\n\
4760 @code{PARM_BOUNDARY} for all arguments.",
4761 unsigned int, (machine_mode mode, const_tree type),
4762 default_function_arg_boundary)
4764 DEFHOOK
4765 (function_arg_round_boundary,
4766 "Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
4767 which is the default value for this hook. You can define this hook to\n\
4768 return a different value if an argument size must be rounded to a larger\n\
4769 value.",
4770 unsigned int, (machine_mode mode, const_tree type),
4771 default_function_arg_round_boundary)
4773 /* Return the diagnostic message string if function without a prototype
4774 is not allowed for this 'val' argument; NULL otherwise. */
4775 DEFHOOK
4776 (invalid_arg_for_unprototyped_fn,
4777 "If defined, this macro returns the diagnostic message when it is\n\
4778 illegal to pass argument @var{val} to function @var{funcdecl}\n\
4779 with prototype @var{typelist}.",
4780 const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
4781 hook_invalid_arg_for_unprototyped_fn)
4783 /* Return an rtx for the return value location of the function
4784 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
4785 DEFHOOK
4786 (function_value,
4787 "\n\
4788 Define this to return an RTX representing the place where a function\n\
4789 returns or receives a value of data type @var{ret_type}, a tree node\n\
4790 representing a data type. @var{fn_decl_or_type} is a tree node\n\
4791 representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a\n\
4792 function being called. If @var{outgoing} is false, the hook should\n\
4793 compute the register in which the caller will see the return value.\n\
4794 Otherwise, the hook should return an RTX representing the place where\n\
4795 a function returns a value.\n\
4797 On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.\n\
4798 (Actually, on most machines, scalar values are returned in the same\n\
4799 place regardless of mode.) The value of the expression is usually a\n\
4800 @code{reg} RTX for the hard register where the return value is stored.\n\
4801 The value can also be a @code{parallel} RTX, if the return value is in\n\
4802 multiple places. See @code{TARGET_FUNCTION_ARG} for an explanation of the\n\
4803 @code{parallel} form. Note that the callee will populate every\n\
4804 location specified in the @code{parallel}, but if the first element of\n\
4805 the @code{parallel} contains the whole return value, callers will use\n\
4806 that element as the canonical location and ignore the others. The m68k\n\
4807 port uses this type of @code{parallel} to return pointers in both\n\
4808 @samp{%a0} (the canonical location) and @samp{%d0}.\n\
4810 If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply\n\
4811 the same promotion rules specified in @code{PROMOTE_MODE} if\n\
4812 @var{valtype} is a scalar type.\n\
4814 If the precise function being called is known, @var{func} is a tree\n\
4815 node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null\n\
4816 pointer. This makes it possible to use a different value-returning\n\
4817 convention for specific functions when all their calls are\n\
4818 known.\n\
4820 Some target machines have ``register windows'' so that the register in\n\
4821 which a function returns its value is not the same as the one in which\n\
4822 the caller sees the value. For such machines, you should return\n\
4823 different RTX depending on @var{outgoing}.\n\
4825 @code{TARGET_FUNCTION_VALUE} is not used for return values with\n\
4826 aggregate data types, because these are returned in another way. See\n\
4827 @code{TARGET_STRUCT_VALUE_RTX} and related macros, below.",
4828 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
4829 default_function_value)
4831 /* Return the rtx for bounds of returned pointer. */
4832 DEFHOOK
4833 (chkp_function_value_bounds,
4834 "Define this to return an RTX representing the place where a function\n\
4835 returns bounds for returned pointers. Arguments meaning is similar to\n\
4836 @code{TARGET_FUNCTION_VALUE}.",
4837 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
4838 default_chkp_function_value_bounds)
4840 /* Return the rtx for the result of a libcall of mode MODE,
4841 calling the function FN_NAME. */
4842 DEFHOOK
4843 (libcall_value,
4844 "Define this hook if the back-end needs to know the name of the libcall\n\
4845 function in order to determine where the result should be returned.\n\
4847 The mode of the result is given by @var{mode} and the name of the called\n\
4848 library function is given by @var{fun}. The hook should return an RTX\n\
4849 representing the place where the library function result will be returned.\n\
4851 If this hook is not defined, then LIBCALL_VALUE will be used.",
4852 rtx, (machine_mode mode, const_rtx fun),
4853 default_libcall_value)
4855 /* Return true if REGNO is a possible register number for
4856 a function value as seen by the caller. */
4857 DEFHOOK
4858 (function_value_regno_p,
4859 "A target hook that return @code{true} if @var{regno} is the number of a hard\n\
4860 register in which the values of called function may come back.\n\
4862 A register whose use for returning values is limited to serving as the\n\
4863 second of a pair (for a value of type @code{double}, say) need not be\n\
4864 recognized by this target hook.\n\
4866 If the machine has register windows, so that the caller and the called\n\
4867 function use different registers for the return value, this target hook\n\
4868 should recognize only the caller's register numbers.\n\
4870 If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.",
4871 bool, (const unsigned int regno),
4872 default_function_value_regno_p)
4874 /* ??? Documenting this hook requires a GFDL license grant. */
4875 DEFHOOK_UNDOC
4876 (internal_arg_pointer,
4877 "Return an rtx for the argument pointer incoming to the\
4878 current function.",
4879 rtx, (void),
4880 default_internal_arg_pointer)
4882 /* Update the current function stack boundary if needed. */
4883 DEFHOOK
4884 (update_stack_boundary,
4885 "Define this macro to update the current function stack boundary if\n\
4886 necessary.",
4887 void, (void), NULL)
4889 /* Handle stack alignment and return an rtx for Dynamic Realign
4890 Argument Pointer if necessary. */
4891 DEFHOOK
4892 (get_drap_rtx,
4893 "This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a\n\
4894 different argument pointer register is needed to access the function's\n\
4895 argument list due to stack realignment. Return @code{NULL} if no DRAP\n\
4896 is needed.",
4897 rtx, (void), NULL)
4899 /* Return true if all function parameters should be spilled to the
4900 stack. */
4901 DEFHOOK
4902 (allocate_stack_slots_for_args,
4903 "When optimization is disabled, this hook indicates whether or not\n\
4904 arguments should be allocated to stack slots. Normally, GCC allocates\n\
4905 stacks slots for arguments when not optimizing in order to make\n\
4906 debugging easier. However, when a function is declared with\n\
4907 @code{__attribute__((naked))}, there is no stack frame, and the compiler\n\
4908 cannot safely move arguments from the registers in which they are passed\n\
4909 to the stack. Therefore, this hook should return true in general, but\n\
4910 false for naked functions. The default implementation always returns true.",
4911 bool, (void),
4912 hook_bool_void_true)
4914 /* Return an rtx for the static chain for FNDECL_OR_TYPE. If INCOMING_P
4915 is true, then it should be for the callee; otherwise for the caller. */
4916 DEFHOOK
4917 (static_chain,
4918 "This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for\n\
4919 targets that may use different static chain locations for different\n\
4920 nested functions. This may be required if the target has function\n\
4921 attributes that affect the calling conventions of the function and\n\
4922 those calling conventions use different static chain locations.\n\
4924 The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.\n\
4926 If the static chain is passed in memory, this hook should be used to\n\
4927 provide rtx giving @code{mem} expressions that denote where they are stored.\n\
4928 Often the @code{mem} expression as seen by the caller will be at an offset\n\
4929 from the stack pointer and the @code{mem} expression as seen by the callee\n\
4930 will be at an offset from the frame pointer.\n\
4931 @findex stack_pointer_rtx\n\
4932 @findex frame_pointer_rtx\n\
4933 @findex arg_pointer_rtx\n\
4934 The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and\n\
4935 @code{arg_pointer_rtx} will have been initialized and should be used\n\
4936 to refer to those items.",
4937 rtx, (const_tree fndecl_or_type, bool incoming_p),
4938 default_static_chain)
4940 /* Fill in the trampoline at MEM with a call to FNDECL and a
4941 static chain value of CHAIN. */
4942 DEFHOOK
4943 (trampoline_init,
4944 "This hook is called to initialize a trampoline.\n\
4945 @var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}\n\
4946 is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an\n\
4947 RTX for the static chain value that should be passed to the function\n\
4948 when it is called.\n\
4950 If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the\n\
4951 first thing this hook should do is emit a block move into @var{m_tramp}\n\
4952 from the memory block returned by @code{assemble_trampoline_template}.\n\
4953 Note that the block move need only cover the constant parts of the\n\
4954 trampoline. If the target isolates the variable parts of the trampoline\n\
4955 to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.\n\
4957 If the target requires any other actions, such as flushing caches or\n\
4958 enabling stack execution, these actions should be performed after\n\
4959 initializing the trampoline proper.",
4960 void, (rtx m_tramp, tree fndecl, rtx static_chain),
4961 default_trampoline_init)
4963 /* Adjust the address of the trampoline in a target-specific way. */
4964 DEFHOOK
4965 (trampoline_adjust_address,
4966 "This hook should perform any machine-specific adjustment in\n\
4967 the address of the trampoline. Its argument contains the address of the\n\
4968 memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}. In case\n\
4969 the address to be used for a function call should be different from the\n\
4970 address at which the template was stored, the different address should\n\
4971 be returned; otherwise @var{addr} should be returned unchanged.\n\
4972 If this hook is not defined, @var{addr} will be used for function calls.",
4973 rtx, (rtx addr), NULL)
4975 DEFHOOKPOD
4976 (custom_function_descriptors,
4977 "This hook should be defined to a power of 2 if the target will benefit\n\
4978 from the use of custom descriptors for nested functions instead of the\n\
4979 standard trampolines. Such descriptors are created at run time on the\n\
4980 stack and made up of data only, but they are non-standard so the generated\n\
4981 code must be prepared to deal with them. This hook should be defined to 0\n\
4982 if the target uses function descriptors for its standard calling sequence,\n\
4983 like for example HP-PA or IA-64. Using descriptors for nested functions\n\
4984 eliminates the need for trampolines that reside on the stack and require\n\
4985 it to be made executable.\n\
4987 The value of the macro is used to parameterize the run-time identification\n\
4988 scheme implemented to distinguish descriptors from function addresses: it\n\
4989 gives the number of bytes by which their address is misaligned compared\n\
4990 with function addresses. The value of 1 will generally work, unless it is\n\
4991 already reserved by the target for another purpose, like for example on ARM.",\
4992 int, -1)
4994 /* Return the number of bytes of its own arguments that a function
4995 pops on returning, or 0 if the function pops no arguments and the
4996 caller must therefore pop them all after the function returns. */
4997 /* ??? tm.texi has no types for the parameters. */
4998 DEFHOOK
4999 (return_pops_args,
5000 "This target hook returns the number of bytes of its own arguments that\n\
5001 a function pops on returning, or 0 if the function pops no arguments\n\
5002 and the caller must therefore pop them all after the function returns.\n\
5004 @var{fundecl} is a C variable whose value is a tree node that describes\n\
5005 the function in question. Normally it is a node of type\n\
5006 @code{FUNCTION_DECL} that describes the declaration of the function.\n\
5007 From this you can obtain the @code{DECL_ATTRIBUTES} of the function.\n\
5009 @var{funtype} is a C variable whose value is a tree node that\n\
5010 describes the function in question. Normally it is a node of type\n\
5011 @code{FUNCTION_TYPE} that describes the data type of the function.\n\
5012 From this it is possible to obtain the data types of the value and\n\
5013 arguments (if known).\n\
5015 When a call to a library function is being considered, @var{fundecl}\n\
5016 will contain an identifier node for the library function. Thus, if\n\
5017 you need to distinguish among various library functions, you can do so\n\
5018 by their names. Note that ``library function'' in this context means\n\
5019 a function used to perform arithmetic, whose name is known specially\n\
5020 in the compiler and was not mentioned in the C code being compiled.\n\
5022 @var{size} is the number of bytes of arguments passed on the\n\
5023 stack. If a variable number of bytes is passed, it is zero, and\n\
5024 argument popping will always be the responsibility of the calling function.\n\
5026 On the VAX, all functions always pop their arguments, so the definition\n\
5027 of this macro is @var{size}. On the 68000, using the standard\n\
5028 calling convention, no functions pop their arguments, so the value of\n\
5029 the macro is always 0 in this case. But an alternative calling\n\
5030 convention is available in which functions that take a fixed number of\n\
5031 arguments pop them but other functions (such as @code{printf}) pop\n\
5032 nothing (the caller pops all). When this convention is in use,\n\
5033 @var{funtype} is examined to determine whether a function takes a fixed\n\
5034 number of arguments.",
5035 int, (tree fundecl, tree funtype, int size),
5036 default_return_pops_args)
5038 /* Return a mode wide enough to copy any function value that might be
5039 returned. */
5040 DEFHOOK
5041 (get_raw_result_mode,
5042 "This target hook returns the mode to be used when accessing raw return\
5043 registers in @code{__builtin_return}. Define this macro if the value\
5044 in @var{reg_raw_mode} is not correct.",
5045 fixed_size_mode, (int regno),
5046 default_get_reg_raw_mode)
5048 /* Return a mode wide enough to copy any argument value that might be
5049 passed. */
5050 DEFHOOK
5051 (get_raw_arg_mode,
5052 "This target hook returns the mode to be used when accessing raw argument\
5053 registers in @code{__builtin_apply_args}. Define this macro if the value\
5054 in @var{reg_raw_mode} is not correct.",
5055 fixed_size_mode, (int regno),
5056 default_get_reg_raw_mode)
5058 HOOK_VECTOR_END (calls)
5060 DEFHOOK
5061 (use_pseudo_pic_reg,
5062 "This hook should return 1 in case pseudo register should be created\n\
5063 for pic_offset_table_rtx during function expand.",
5064 bool, (void),
5065 hook_bool_void_false)
5067 DEFHOOK
5068 (init_pic_reg,
5069 "Perform a target dependent initialization of pic_offset_table_rtx.\n\
5070 This hook is called at the start of register allocation.",
5071 void, (void),
5072 hook_void_void)
5074 /* Return the diagnostic message string if conversion from FROMTYPE
5075 to TOTYPE is not allowed, NULL otherwise. */
5076 DEFHOOK
5077 (invalid_conversion,
5078 "If defined, this macro returns the diagnostic message when it is\n\
5079 invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}\n\
5080 if validity should be determined by the front end.",
5081 const char *, (const_tree fromtype, const_tree totype),
5082 hook_constcharptr_const_tree_const_tree_null)
5084 /* Return the diagnostic message string if the unary operation OP is
5085 not permitted on TYPE, NULL otherwise. */
5086 DEFHOOK
5087 (invalid_unary_op,
5088 "If defined, this macro returns the diagnostic message when it is\n\
5089 invalid to apply operation @var{op} (where unary plus is denoted by\n\
5090 @code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}\n\
5091 if validity should be determined by the front end.",
5092 const char *, (int op, const_tree type),
5093 hook_constcharptr_int_const_tree_null)
5095 /* Return the diagnostic message string if the binary operation OP
5096 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
5097 DEFHOOK
5098 (invalid_binary_op,
5099 "If defined, this macro returns the diagnostic message when it is\n\
5100 invalid to apply operation @var{op} to operands of types @var{type1}\n\
5101 and @var{type2}, or @code{NULL} if validity should be determined by\n\
5102 the front end.",
5103 const char *, (int op, const_tree type1, const_tree type2),
5104 hook_constcharptr_int_const_tree_const_tree_null)
5106 /* If values of TYPE are promoted to some other type when used in
5107 expressions (analogous to the integer promotions), return that type,
5108 or NULL_TREE otherwise. */
5109 DEFHOOK
5110 (promoted_type,
5111 "If defined, this target hook returns the type to which values of\n\
5112 @var{type} should be promoted when they appear in expressions,\n\
5113 analogous to the integer promotions, or @code{NULL_TREE} to use the\n\
5114 front end's normal promotion rules. This hook is useful when there are\n\
5115 target-specific types with special promotion rules.\n\
5116 This is currently used only by the C and C++ front ends.",
5117 tree, (const_tree type),
5118 hook_tree_const_tree_null)
5120 /* Convert EXPR to TYPE, if target-specific types with special conversion
5121 rules are involved. Return the converted expression, or NULL to apply
5122 the standard conversion rules. */
5123 DEFHOOK
5124 (convert_to_type,
5125 "If defined, this hook returns the result of converting @var{expr} to\n\
5126 @var{type}. It should return the converted expression,\n\
5127 or @code{NULL_TREE} to apply the front end's normal conversion rules.\n\
5128 This hook is useful when there are target-specific types with special\n\
5129 conversion rules.\n\
5130 This is currently used only by the C and C++ front ends.",
5131 tree, (tree type, tree expr),
5132 hook_tree_tree_tree_null)
5134 DEFHOOK
5135 (can_change_mode_class,
5136 "This hook returns true if it is possible to bitcast values held in\n\
5137 registers of class @var{rclass} from mode @var{from} to mode @var{to}\n\
5138 and if doing so preserves the low-order bits that are common to both modes.\n\
5139 The result is only meaningful if @var{rclass} has registers that can hold\n\
5140 both @code{from} and @code{to}. The default implementation returns true.\n\
5142 As an example of when such bitcasting is invalid, loading 32-bit integer or\n\
5143 floating-point objects into floating-point registers on Alpha extends them\n\
5144 to 64 bits. Therefore loading a 64-bit object and then storing it as a\n\
5145 32-bit object does not store the low-order 32 bits, as would be the case\n\
5146 for a normal register. Therefore, @file{alpha.h} defines\n\
5147 @code{TARGET_CAN_CHANGE_MODE_CLASS} to return:\n\
5149 @smallexample\n\
5150 (GET_MODE_SIZE (from) == GET_MODE_SIZE (to)\n\
5151 || !reg_classes_intersect_p (FLOAT_REGS, rclass))\n\
5152 @end smallexample\n\
5154 Even if storing from a register in mode @var{to} would be valid,\n\
5155 if both @var{from} and @code{raw_reg_mode} for @var{rclass} are wider\n\
5156 than @code{word_mode}, then we must prevent @var{to} narrowing the\n\
5157 mode. This happens when the middle-end assumes that it can load\n\
5158 or store pieces of an @var{N}-word pseudo, and that the pseudo will\n\
5159 eventually be allocated to @var{N} @code{word_mode} hard registers.\n\
5160 Failure to prevent this kind of mode change will result in the\n\
5161 entire @code{raw_reg_mode} being modified instead of the partial\n\
5162 value that the middle-end intended.",
5163 bool, (machine_mode from, machine_mode to, reg_class_t rclass),
5164 hook_bool_mode_mode_reg_class_t_true)
5166 /* Change pseudo allocno class calculated by IRA. */
5167 DEFHOOK
5168 (ira_change_pseudo_allocno_class,
5169 "A target hook which can change allocno class for given pseudo from\n\
5170 allocno and best class calculated by IRA.\n\
5172 The default version of this target hook always returns given class.",
5173 reg_class_t, (int, reg_class_t, reg_class_t),
5174 default_ira_change_pseudo_allocno_class)
5176 /* Return true if we use LRA instead of reload. */
5177 DEFHOOK
5178 (lra_p,
5179 "A target hook which returns true if we use LRA instead of reload pass.\
5181 The default version of this target hook returns true. New ports\
5182 should use LRA, and existing ports are encouraged to convert.",
5183 bool, (void),
5184 default_lra_p)
5186 /* Return register priority of given hard regno for the current target. */
5187 DEFHOOK
5188 (register_priority,
5189 "A target hook which returns the register priority number to which the\
5190 register @var{hard_regno} belongs to. The bigger the number, the\
5191 more preferable the hard register usage (when all other conditions are\
5192 the same). This hook can be used to prefer some hard register over\
5193 others in LRA. For example, some x86-64 register usage needs\
5194 additional prefix which makes instructions longer. The hook can\
5195 return lower priority number for such registers make them less favorable\
5196 and as result making the generated code smaller.\
5198 The default version of this target hook returns always zero.",
5199 int, (int),
5200 default_register_priority)
5202 /* Return true if we need register usage leveling. */
5203 DEFHOOK
5204 (register_usage_leveling_p,
5205 "A target hook which returns true if we need register usage leveling.\
5206 That means if a few hard registers are equally good for the\
5207 assignment, we choose the least used hard register. The register\
5208 usage leveling may be profitable for some targets. Don't use the\
5209 usage leveling for targets with conditional execution or targets\
5210 with big register files as it hurts if-conversion and cross-jumping\
5211 optimizations.\
5213 The default version of this target hook returns always false.",
5214 bool, (void),
5215 default_register_usage_leveling_p)
5217 /* Return true if maximal address displacement can be different. */
5218 DEFHOOK
5219 (different_addr_displacement_p,
5220 "A target hook which returns true if an address with the same structure\
5221 can have different maximal legitimate displacement. For example, the\
5222 displacement can depend on memory mode or on operand combinations in\
5223 the insn.\
5225 The default version of this target hook returns always false.",
5226 bool, (void),
5227 default_different_addr_displacement_p)
5229 /* Determine class for spilling pseudos of given mode into registers
5230 instead of memory. */
5231 DEFHOOK
5232 (spill_class,
5233 "This hook defines a class of registers which could be used for spilling\
5234 pseudos of the given mode and class, or @code{NO_REGS} if only memory\
5235 should be used. Not defining this hook is equivalent to returning\
5236 @code{NO_REGS} for all inputs.",
5237 reg_class_t, (reg_class_t, machine_mode),
5238 NULL)
5240 /* Determine an additional allocno class. */
5241 DEFHOOK
5242 (additional_allocno_class_p,
5243 "This hook should return @code{true} if given class of registers should\
5244 be an allocno class in any way. Usually RA uses only one register\
5245 class from all classes containing the same register set. In some\
5246 complicated cases, you need to have two or more such classes as\
5247 allocno ones for RA correct work. Not defining this hook is\
5248 equivalent to returning @code{false} for all inputs.",
5249 bool, (reg_class_t),
5250 hook_bool_reg_class_t_false)
5252 DEFHOOK
5253 (cstore_mode,
5254 "This hook defines the machine mode to use for the boolean result of\
5255 conditional store patterns. The ICODE argument is the instruction code\
5256 for the cstore being performed. Not definiting this hook is the same\
5257 as accepting the mode encoded into operand 0 of the cstore expander\
5258 patterns.",
5259 scalar_int_mode, (enum insn_code icode),
5260 default_cstore_mode)
5262 /* This target hook allows the backend to compute the register pressure
5263 classes to use. */
5264 DEFHOOK
5265 (compute_pressure_classes,
5266 "A target hook which lets a backend compute the set of pressure classes to\
5267 be used by those optimization passes which take register pressure into\
5268 account, as opposed to letting IRA compute them. It returns the number of\
5269 register classes stored in the array @var{pressure_classes}.",
5270 int, (enum reg_class *pressure_classes), NULL)
5272 /* True if a structure, union or array with MODE containing FIELD should
5273 be accessed using BLKmode. */
5274 DEFHOOK
5275 (member_type_forces_blk,
5276 "Return true if a structure, union or array containing @var{field} should\n\
5277 be accessed using @code{BLKMODE}.\n\
5279 If @var{field} is the only field in the structure, @var{mode} is its\n\
5280 mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the\n\
5281 case where structures of one field would require the structure's mode to\n\
5282 retain the field's mode.\n\
5284 Normally, this is not needed.",
5285 bool, (const_tree field, machine_mode mode),
5286 default_member_type_forces_blk)
5288 /* See tree-ssa-math-opts.c:divmod_candidate_p for conditions
5289 that gate the divod transform. */
5290 DEFHOOK
5291 (expand_divmod_libfunc,
5292 "Define this hook for enabling divmod transform if the port does not have\n\
5293 hardware divmod insn but defines target-specific divmod libfuncs.",
5294 void, (rtx libfunc, machine_mode mode, rtx op0, rtx op1, rtx *quot, rtx *rem),
5295 NULL)
5297 /* Return the class for a secondary reload, and fill in extra information. */
5298 DEFHOOK
5299 (secondary_reload,
5300 "Many machines have some registers that cannot be copied directly to or\n\
5301 from memory or even from other types of registers. An example is the\n\
5302 @samp{MQ} register, which on most machines, can only be copied to or\n\
5303 from general registers, but not memory. Below, we shall be using the\n\
5304 term 'intermediate register' when a move operation cannot be performed\n\
5305 directly, but has to be done by copying the source into the intermediate\n\
5306 register first, and then copying the intermediate register to the\n\
5307 destination. An intermediate register always has the same mode as\n\
5308 source and destination. Since it holds the actual value being copied,\n\
5309 reload might apply optimizations to re-use an intermediate register\n\
5310 and eliding the copy from the source when it can determine that the\n\
5311 intermediate register still holds the required value.\n\
5313 Another kind of secondary reload is required on some machines which\n\
5314 allow copying all registers to and from memory, but require a scratch\n\
5315 register for stores to some memory locations (e.g., those with symbolic\n\
5316 address on the RT, and those with certain symbolic address on the SPARC\n\
5317 when compiling PIC)@. Scratch registers need not have the same mode\n\
5318 as the value being copied, and usually hold a different value than\n\
5319 that being copied. Special patterns in the md file are needed to\n\
5320 describe how the copy is performed with the help of the scratch register;\n\
5321 these patterns also describe the number, register class(es) and mode(s)\n\
5322 of the scratch register(s).\n\
5324 In some cases, both an intermediate and a scratch register are required.\n\
5326 For input reloads, this target hook is called with nonzero @var{in_p},\n\
5327 and @var{x} is an rtx that needs to be copied to a register of class\n\
5328 @var{reload_class} in @var{reload_mode}. For output reloads, this target\n\
5329 hook is called with zero @var{in_p}, and a register of class @var{reload_class}\n\
5330 needs to be copied to rtx @var{x} in @var{reload_mode}.\n\
5332 If copying a register of @var{reload_class} from/to @var{x} requires\n\
5333 an intermediate register, the hook @code{secondary_reload} should\n\
5334 return the register class required for this intermediate register.\n\
5335 If no intermediate register is required, it should return NO_REGS.\n\
5336 If more than one intermediate register is required, describe the one\n\
5337 that is closest in the copy chain to the reload register.\n\
5339 If scratch registers are needed, you also have to describe how to\n\
5340 perform the copy from/to the reload register to/from this\n\
5341 closest intermediate register. Or if no intermediate register is\n\
5342 required, but still a scratch register is needed, describe the\n\
5343 copy from/to the reload register to/from the reload operand @var{x}.\n\
5345 You do this by setting @code{sri->icode} to the instruction code of a pattern\n\
5346 in the md file which performs the move. Operands 0 and 1 are the output\n\
5347 and input of this copy, respectively. Operands from operand 2 onward are\n\
5348 for scratch operands. These scratch operands must have a mode, and a\n\
5349 single-register-class\n\
5350 @c [later: or memory]\n\
5351 output constraint.\n\
5353 When an intermediate register is used, the @code{secondary_reload}\n\
5354 hook will be called again to determine how to copy the intermediate\n\
5355 register to/from the reload operand @var{x}, so your hook must also\n\
5356 have code to handle the register class of the intermediate operand.\n\
5358 @c [For later: maybe we'll allow multi-alternative reload patterns -\n\
5359 @c the port maintainer could name a mov<mode> pattern that has clobbers -\n\
5360 @c and match the constraints of input and output to determine the required\n\
5361 @c alternative. A restriction would be that constraints used to match\n\
5362 @c against reloads registers would have to be written as register class\n\
5363 @c constraints, or we need a new target macro / hook that tells us if an\n\
5364 @c arbitrary constraint can match an unknown register of a given class.\n\
5365 @c Such a macro / hook would also be useful in other places.]\n\
5368 @var{x} might be a pseudo-register or a @code{subreg} of a\n\
5369 pseudo-register, which could either be in a hard register or in memory.\n\
5370 Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is\n\
5371 in memory and the hard register number if it is in a register.\n\
5373 Scratch operands in memory (constraint @code{\"=m\"} / @code{\"=&m\"}) are\n\
5374 currently not supported. For the time being, you will have to continue\n\
5375 to use @code{TARGET_SECONDARY_MEMORY_NEEDED} for that purpose.\n\
5377 @code{copy_cost} also uses this target hook to find out how values are\n\
5378 copied. If you want it to include some extra cost for the need to allocate\n\
5379 (a) scratch register(s), set @code{sri->extra_cost} to the additional cost.\n\
5380 Or if two dependent moves are supposed to have a lower cost than the sum\n\
5381 of the individual moves due to expected fortuitous scheduling and/or special\n\
5382 forwarding logic, you can set @code{sri->extra_cost} to a negative amount.",
5383 reg_class_t,
5384 (bool in_p, rtx x, reg_class_t reload_class, machine_mode reload_mode,
5385 secondary_reload_info *sri),
5386 default_secondary_reload)
5388 DEFHOOK
5389 (secondary_memory_needed,
5390 "Certain machines have the property that some registers cannot be copied\n\
5391 to some other registers without using memory. Define this hook on\n\
5392 those machines to return true if objects of mode @var{m} in registers\n\
5393 of @var{class1} can only be copied to registers of class @var{class2} by\n\
5394 storing a register of @var{class1} into memory and loading that memory\n\
5395 location into a register of @var{class2}. The default definition returns\n\
5396 false for all inputs.",
5397 bool, (machine_mode mode, reg_class_t class1, reg_class_t class2),
5398 hook_bool_mode_reg_class_t_reg_class_t_false)
5400 DEFHOOK
5401 (secondary_memory_needed_mode,
5402 "If @code{TARGET_SECONDARY_MEMORY_NEEDED} tells the compiler to use memory\n\
5403 when moving between two particular registers of mode @var{mode},\n\
5404 this hook specifies the mode that the memory should have.\n\
5406 The default depends on @code{TARGET_LRA_P}. Without LRA, the default\n\
5407 is to use a word-sized mode for integral modes that are smaller than a\n\
5408 a word. This is right thing to do on most machines because it ensures\n\
5409 that all bits of the register are copied and prevents accesses to the\n\
5410 registers in a narrower mode, which some machines prohibit for\n\
5411 floating-point registers.\n\
5413 However, this default behavior is not correct on some machines, such as\n\
5414 the DEC Alpha, that store short integers in floating-point registers\n\
5415 differently than in integer registers. On those machines, the default\n\
5416 widening will not work correctly and you must define this hook to\n\
5417 suppress that widening in some cases. See the file @file{alpha.c} for\n\
5418 details.\n\
5420 With LRA, the default is to use @var{mode} unmodified.",
5421 machine_mode, (machine_mode mode),
5422 default_secondary_memory_needed_mode)
5424 /* Given an rtx X being reloaded into a reg required to be in class CLASS,
5425 return the class of reg to actually use. */
5426 DEFHOOK
5427 (preferred_reload_class,
5428 "A target hook that places additional restrictions on the register class\n\
5429 to use when it is necessary to copy value @var{x} into a register in class\n\
5430 @var{rclass}. The value is a register class; perhaps @var{rclass}, or perhaps\n\
5431 another, smaller class.\n\
5433 The default version of this hook always returns value of @code{rclass} argument.\n\
5435 Sometimes returning a more restrictive class makes better code. For\n\
5436 example, on the 68000, when @var{x} is an integer constant that is in range\n\
5437 for a @samp{moveq} instruction, the value of this macro is always\n\
5438 @code{DATA_REGS} as long as @var{rclass} includes the data registers.\n\
5439 Requiring a data register guarantees that a @samp{moveq} will be used.\n\
5441 One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return\n\
5442 @var{rclass} is if @var{x} is a legitimate constant which cannot be\n\
5443 loaded into some register class. By returning @code{NO_REGS} you can\n\
5444 force @var{x} into a memory location. For example, rs6000 can load\n\
5445 immediate values into general-purpose registers, but does not have an\n\
5446 instruction for loading an immediate value into a floating-point\n\
5447 register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when\n\
5448 @var{x} is a floating-point constant. If the constant can't be loaded\n\
5449 into any kind of register, code generation will be better if\n\
5450 @code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead\n\
5451 of using @code{TARGET_PREFERRED_RELOAD_CLASS}.\n\
5453 If an insn has pseudos in it after register allocation, reload will go\n\
5454 through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}\n\
5455 to find the best one. Returning @code{NO_REGS}, in this case, makes\n\
5456 reload add a @code{!} in front of the constraint: the x86 back-end uses\n\
5457 this feature to discourage usage of 387 registers when math is done in\n\
5458 the SSE registers (and vice versa).",
5459 reg_class_t,
5460 (rtx x, reg_class_t rclass),
5461 default_preferred_reload_class)
5463 /* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
5464 input reloads. */
5465 DEFHOOK
5466 (preferred_output_reload_class,
5467 "Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of\n\
5468 input reloads.\n\
5470 The default version of this hook always returns value of @code{rclass}\n\
5471 argument.\n\
5473 You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage\n\
5474 reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.",
5475 reg_class_t,
5476 (rtx x, reg_class_t rclass),
5477 default_preferred_output_reload_class)
5479 DEFHOOK
5480 (class_likely_spilled_p,
5481 "A target hook which returns @code{true} if pseudos that have been assigned\n\
5482 to registers of class @var{rclass} would likely be spilled because\n\
5483 registers of @var{rclass} are needed for spill registers.\n\
5485 The default version of this target hook returns @code{true} if @var{rclass}\n\
5486 has exactly one register and @code{false} otherwise. On most machines, this\n\
5487 default should be used. For generally register-starved machines, such as\n\
5488 i386, or machines with right register constraints, such as SH, this hook\n\
5489 can be used to avoid excessive spilling.\n\
5491 This hook is also used by some of the global intra-procedural code\n\
5492 transformations to throtle code motion, to avoid increasing register\n\
5493 pressure.",
5494 bool, (reg_class_t rclass),
5495 default_class_likely_spilled_p)
5497 /* Return the maximum number of consecutive registers
5498 needed to represent mode MODE in a register of class RCLASS. */
5499 DEFHOOK
5500 (class_max_nregs,
5501 "A target hook returns the maximum number of consecutive registers\n\
5502 of class @var{rclass} needed to hold a value of mode @var{mode}.\n\
5504 This is closely related to the macro @code{TARGET_HARD_REGNO_NREGS}.\n\
5505 In fact, the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},\n\
5506 @var{mode})} target hook should be the maximum value of\n\
5507 @code{TARGET_HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}\n\
5508 values in the class @var{rclass}.\n\
5510 This target hook helps control the handling of multiple-word values\n\
5511 in the reload pass.\n\
5513 The default version of this target hook returns the size of @var{mode}\n\
5514 in words.",
5515 unsigned char, (reg_class_t rclass, machine_mode mode),
5516 default_class_max_nregs)
5518 DEFHOOK
5519 (preferred_rename_class,
5520 "A target hook that places additional preference on the register\
5521 class to use when it is necessary to rename a register in class\
5522 @var{rclass} to another class, or perhaps @var{NO_REGS}, if no\
5523 preferred register class is found or hook @code{preferred_rename_class}\
5524 is not implemented.\
5525 Sometimes returning a more restrictive class makes better code. For\
5526 example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\
5527 smaller than instructions using @code{GENERIC_REGS}. By returning\
5528 @code{LO_REGS} from @code{preferred_rename_class}, code size can\
5529 be reduced.",
5530 reg_class_t, (reg_class_t rclass),
5531 default_preferred_rename_class)
5533 /* This target hook allows the backend to avoid unsafe substitution
5534 during register allocation. */
5535 DEFHOOK
5536 (cannot_substitute_mem_equiv_p,
5537 "A target hook which returns @code{true} if @var{subst} can't\n\
5538 substitute safely pseudos with equivalent memory values during\n\
5539 register allocation.\n\
5540 The default version of this target hook returns @code{false}.\n\
5541 On most machines, this default should be used. For generally\n\
5542 machines with non orthogonal register usage for addressing, such\n\
5543 as SH, this hook can be used to avoid excessive spilling.",
5544 bool, (rtx subst),
5545 hook_bool_rtx_false)
5547 /* This target hook allows the backend to legitimize base plus
5548 displacement addressing. */
5549 DEFHOOK
5550 (legitimize_address_displacement,
5551 "A target hook which returns @code{true} if *@var{disp} is\n\
5552 legitimezed to valid address displacement with subtracting *@var{offset}\n\
5553 at memory mode @var{mode}.\n\
5554 The default version of this target hook returns @code{false}.\n\
5555 This hook will benefit machines with limited base plus displacement\n\
5556 addressing.",
5557 bool, (rtx *disp, rtx *offset, machine_mode mode),
5558 default_legitimize_address_displacement)
5560 /* This target hook allows the backend to perform additional
5561 processing while initializing for variable expansion. */
5562 DEFHOOK
5563 (expand_to_rtl_hook,
5564 "This hook is called just before expansion into rtl, allowing the target\n\
5565 to perform additional initializations or analysis before the expansion.\n\
5566 For example, the rs6000 port uses it to allocate a scratch stack slot\n\
5567 for use in copying SDmode values between memory and floating point\n\
5568 registers whenever the function being expanded has any SDmode\n\
5569 usage.",
5570 void, (void),
5571 hook_void_void)
5573 /* This target hook allows the backend to perform additional
5574 instantiations on rtx that are not actually in insns yet,
5575 but will be later. */
5576 DEFHOOK
5577 (instantiate_decls,
5578 "This hook allows the backend to perform additional instantiations on rtl\n\
5579 that are not actually in any insns yet, but will be later.",
5580 void, (void),
5581 hook_void_void)
5583 DEFHOOK
5584 (hard_regno_nregs,
5585 "This hook returns the number of consecutive hard registers, starting\n\
5586 at register number @var{regno}, required to hold a value of mode\n\
5587 @var{mode}. This hook must never return zero, even if a register\n\
5588 cannot hold the requested mode - indicate that with\n\
5589 @code{TARGET_HARD_REGNO_MODE_OK} and/or\n\
5590 @code{TARGET_CAN_CHANGE_MODE_CLASS} instead.\n\
5592 The default definition returns the number of words in @var{mode}.",
5593 unsigned int, (unsigned int regno, machine_mode mode),
5594 default_hard_regno_nregs)
5596 DEFHOOK
5597 (hard_regno_mode_ok,
5598 "This hook returns true if it is permissible to store a value\n\
5599 of mode @var{mode} in hard register number @var{regno} (or in several\n\
5600 registers starting with that one). The default definition returns true\n\
5601 unconditionally.\n\
5603 You need not include code to check for the numbers of fixed registers,\n\
5604 because the allocation mechanism considers them to be always occupied.\n\
5606 @cindex register pairs\n\
5607 On some machines, double-precision values must be kept in even/odd\n\
5608 register pairs. You can implement that by defining this hook to reject\n\
5609 odd register numbers for such modes.\n\
5611 The minimum requirement for a mode to be OK in a register is that the\n\
5612 @samp{mov@var{mode}} instruction pattern support moves between the\n\
5613 register and other hard register in the same class and that moving a\n\
5614 value into the register and back out not alter it.\n\
5616 Since the same instruction used to move @code{word_mode} will work for\n\
5617 all narrower integer modes, it is not necessary on any machine for\n\
5618 this hook to distinguish between these modes, provided you define\n\
5619 patterns @samp{movhi}, etc., to take advantage of this. This is\n\
5620 useful because of the interaction between @code{TARGET_HARD_REGNO_MODE_OK}\n\
5621 and @code{TARGET_MODES_TIEABLE_P}; it is very desirable for all integer\n\
5622 modes to be tieable.\n\
5624 Many machines have special registers for floating point arithmetic.\n\
5625 Often people assume that floating point machine modes are allowed only\n\
5626 in floating point registers. This is not true. Any registers that\n\
5627 can hold integers can safely @emph{hold} a floating point machine\n\
5628 mode, whether or not floating arithmetic can be done on it in those\n\
5629 registers. Integer move instructions can be used to move the values.\n\
5631 On some machines, though, the converse is true: fixed-point machine\n\
5632 modes may not go in floating registers. This is true if the floating\n\
5633 registers normalize any value stored in them, because storing a\n\
5634 non-floating value there would garble it. In this case,\n\
5635 @code{TARGET_HARD_REGNO_MODE_OK} should reject fixed-point machine modes in\n\
5636 floating registers. But if the floating registers do not automatically\n\
5637 normalize, if you can store any bit pattern in one and retrieve it\n\
5638 unchanged without a trap, then any machine mode may go in a floating\n\
5639 register, so you can define this hook to say so.\n\
5641 The primary significance of special floating registers is rather that\n\
5642 they are the registers acceptable in floating point arithmetic\n\
5643 instructions. However, this is of no concern to\n\
5644 @code{TARGET_HARD_REGNO_MODE_OK}. You handle it by writing the proper\n\
5645 constraints for those instructions.\n\
5647 On some machines, the floating registers are especially slow to access,\n\
5648 so that it is better to store a value in a stack frame than in such a\n\
5649 register if floating point arithmetic is not being done. As long as the\n\
5650 floating registers are not in class @code{GENERAL_REGS}, they will not\n\
5651 be used unless some pattern's constraint asks for one.",
5652 bool, (unsigned int regno, machine_mode mode),
5653 hook_bool_uint_mode_true)
5655 DEFHOOK
5656 (modes_tieable_p,
5657 "This hook returns true if a value of mode @var{mode1} is accessible\n\
5658 in mode @var{mode2} without copying.\n\
5660 If @code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode1})} and\n\
5661 @code{TARGET_HARD_REGNO_MODE_OK (@var{r}, @var{mode2})} are always\n\
5662 the same for any @var{r}, then\n\
5663 @code{TARGET_MODES_TIEABLE_P (@var{mode1}, @var{mode2})}\n\
5664 should be true. If they differ for any @var{r}, you should define\n\
5665 this hook to return false unless some other mechanism ensures the\n\
5666 accessibility of the value in a narrower mode.\n\
5668 You should define this hook to return true in as many cases as\n\
5669 possible since doing so will allow GCC to perform better register\n\
5670 allocation. The default definition returns true unconditionally.",
5671 bool, (machine_mode mode1, machine_mode mode2),
5672 hook_bool_mode_mode_true)
5674 /* Return true if is OK to use a hard register REGNO as scratch register
5675 in peephole2. */
5676 DEFHOOK
5677 (hard_regno_scratch_ok,
5678 "This target hook should return @code{true} if it is OK to use a hard register\n\
5679 @var{regno} as scratch reg in peephole2.\n\
5681 One common use of this macro is to prevent using of a register that\n\
5682 is not saved by a prologue in an interrupt handler.\n\
5684 The default version of this hook always returns @code{true}.",
5685 bool, (unsigned int regno),
5686 default_hard_regno_scratch_ok)
5688 DEFHOOK
5689 (hard_regno_call_part_clobbered,
5690 "This hook should return true if @var{regno} is partly call-saved and\n\
5691 partly call-clobbered, and if a value of mode @var{mode} would be partly\n\
5692 clobbered by a call. For example, if the low 32 bits of @var{regno} are\n\
5693 preserved across a call but higher bits are clobbered, this hook should\n\
5694 return true for a 64-bit mode but false for a 32-bit mode.\n\
5696 The default implementation returns false, which is correct\n\
5697 for targets that don't have partly call-clobbered registers.",
5698 bool, (unsigned int regno, machine_mode mode),
5699 hook_bool_uint_mode_false)
5701 /* Return the smallest number of different values for which it is best to
5702 use a jump-table instead of a tree of conditional branches. */
5703 DEFHOOK
5704 (case_values_threshold,
5705 "This function return the smallest number of different values for which it\n\
5706 is best to use a jump-table instead of a tree of conditional branches.\n\
5707 The default is four for machines with a @code{casesi} instruction and\n\
5708 five otherwise. This is best for most machines.",
5709 unsigned int, (void),
5710 default_case_values_threshold)
5712 DEFHOOK
5713 (starting_frame_offset,
5714 "This hook returns the offset from the frame pointer to the first local\n\
5715 variable slot to be allocated. If @code{FRAME_GROWS_DOWNWARD}, it is the\n\
5716 offset to @emph{end} of the first slot allocated, otherwise it is the\n\
5717 offset to @emph{beginning} of the first slot allocated. The default\n\
5718 implementation returns 0.",
5719 HOST_WIDE_INT, (void),
5720 hook_hwi_void_0)
5722 /* Optional callback to advise the target to compute the frame layout. */
5723 DEFHOOK
5724 (compute_frame_layout,
5725 "This target hook is called once each time the frame layout needs to be\n\
5726 recalculated. The calculations can be cached by the target and can then\n\
5727 be used by @code{INITIAL_ELIMINATION_OFFSET} instead of re-computing the\n\
5728 layout on every invocation of that hook. This is particularly useful\n\
5729 for targets that have an expensive frame layout function. Implementing\n\
5730 this callback is optional.",
5731 void, (void),
5732 hook_void_void)
5734 /* Return true if a function must have and use a frame pointer. */
5735 DEFHOOK
5736 (frame_pointer_required,
5737 "This target hook should return @code{true} if a function must have and use\n\
5738 a frame pointer. This target hook is called in the reload pass. If its return\n\
5739 value is @code{true} the function will have a frame pointer.\n\
5741 This target hook can in principle examine the current function and decide\n\
5742 according to the facts, but on most machines the constant @code{false} or the\n\
5743 constant @code{true} suffices. Use @code{false} when the machine allows code\n\
5744 to be generated with no frame pointer, and doing so saves some time or space.\n\
5745 Use @code{true} when there is no possible advantage to avoiding a frame\n\
5746 pointer.\n\
5748 In certain cases, the compiler does not know how to produce valid code\n\
5749 without a frame pointer. The compiler recognizes those cases and\n\
5750 automatically gives the function a frame pointer regardless of what\n\
5751 @code{targetm.frame_pointer_required} returns. You don't need to worry about\n\
5752 them.\n\
5754 In a function that does not require a frame pointer, the frame pointer\n\
5755 register can be allocated for ordinary usage, unless you mark it as a\n\
5756 fixed register. See @code{FIXED_REGISTERS} for more information.\n\
5758 Default return value is @code{false}.",
5759 bool, (void),
5760 hook_bool_void_false)
5762 /* Returns true if the compiler is allowed to try to replace register number
5763 from-reg with register number to-reg. */
5764 DEFHOOK
5765 (can_eliminate,
5766 "This target hook should return @code{true} if the compiler is allowed to\n\
5767 try to replace register number @var{from_reg} with register number\n\
5768 @var{to_reg}. This target hook will usually be @code{true}, since most of the\n\
5769 cases preventing register elimination are things that the compiler already\n\
5770 knows about.\n\
5772 Default return value is @code{true}.",
5773 bool, (const int from_reg, const int to_reg),
5774 hook_bool_const_int_const_int_true)
5776 /* Modify any or all of fixed_regs, call_used_regs, global_regs,
5777 reg_names, and reg_class_contents to account of the vagaries of the
5778 target. */
5779 DEFHOOK
5780 (conditional_register_usage,
5781 "This hook may conditionally modify five variables\n\
5782 @code{fixed_regs}, @code{call_used_regs}, @code{global_regs},\n\
5783 @code{reg_names}, and @code{reg_class_contents}, to take into account\n\
5784 any dependence of these register sets on target flags. The first three\n\
5785 of these are of type @code{char []} (interpreted as boolean vectors).\n\
5786 @code{global_regs} is a @code{const char *[]}, and\n\
5787 @code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is\n\
5788 called, @code{fixed_regs}, @code{call_used_regs},\n\
5789 @code{reg_class_contents}, and @code{reg_names} have been initialized\n\
5790 from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},\n\
5791 @code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.\n\
5792 @code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},\n\
5793 @option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}\n\
5794 command options have been applied.\n\
5796 @cindex disabling certain registers\n\
5797 @cindex controlling register usage\n\
5798 If the usage of an entire class of registers depends on the target\n\
5799 flags, you may indicate this to GCC by using this macro to modify\n\
5800 @code{fixed_regs} and @code{call_used_regs} to 1 for each of the\n\
5801 registers in the classes which should not be used by GCC@. Also make\n\
5802 @code{define_register_constraint}s return @code{NO_REGS} for constraints\n\
5803 that shouldn't be used.\n\
5805 (However, if this class is not included in @code{GENERAL_REGS} and all\n\
5806 of the insn patterns whose constraints permit this class are\n\
5807 controlled by target switches, then GCC will automatically avoid using\n\
5808 these registers when the target switches are opposed to them.)",
5809 void, (void),
5810 hook_void_void)
5812 DEFHOOK
5813 (stack_clash_protection_final_dynamic_probe,
5814 "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.",
5815 bool, (rtx residual),
5816 default_stack_clash_protection_final_dynamic_probe)
5819 /* Functions specific to the C family of frontends. */
5820 #undef HOOK_PREFIX
5821 #define HOOK_PREFIX "TARGET_C_"
5822 HOOK_VECTOR (TARGET_C, c)
5824 /* ??? Documenting this hook requires a GFDL license grant. */
5825 DEFHOOK_UNDOC
5826 (mode_for_suffix,
5827 "Return machine mode for non-standard constant literal suffix @var{c},\
5828 or VOIDmode if non-standard suffixes are unsupported.",
5829 machine_mode, (char c),
5830 default_mode_for_suffix)
5832 DEFHOOK
5833 (excess_precision,
5834 "Return a value, with the same meaning as the C99 macro\
5835 @code{FLT_EVAL_METHOD} that describes which excess precision should be\
5836 applied. @var{type} is either @code{EXCESS_PRECISION_TYPE_IMPLICIT},\
5837 @code{EXCESS_PRECISION_TYPE_FAST}, or\
5838 @code{EXCESS_PRECISION_TYPE_STANDARD}. For\
5839 @code{EXCESS_PRECISION_TYPE_IMPLICIT}, the target should return which\
5840 precision and range operations will be implictly evaluated in regardless\
5841 of the excess precision explicitly added. For\
5842 @code{EXCESS_PRECISION_TYPE_STANDARD} and\
5843 @code{EXCESS_PRECISION_TYPE_FAST}, the target should return the\
5844 explicit excess precision that should be added depending on the\
5845 value set for @option{-fexcess-precision=@r{[}standard@r{|}fast@r{]}}.\
5846 Note that unpredictable explicit excess precision does not make sense,\
5847 so a target should never return @code{FLT_EVAL_METHOD_UNPREDICTABLE}\
5848 when @var{type} is @code{EXCESS_PRECISION_TYPE_STANDARD} or\
5849 @code{EXCESS_PRECISION_TYPE_FAST}.",
5850 enum flt_eval_method, (enum excess_precision_type type),
5851 default_excess_precision)
5853 HOOK_VECTOR_END (c)
5855 /* Functions specific to the C++ frontend. */
5856 #undef HOOK_PREFIX
5857 #define HOOK_PREFIX "TARGET_CXX_"
5858 HOOK_VECTOR (TARGET_CXX, cxx)
5860 /* Return the integer type used for guard variables. */
5861 DEFHOOK
5862 (guard_type,
5863 "Define this hook to override the integer type used for guard variables.\n\
5864 These are used to implement one-time construction of static objects. The\n\
5865 default is long_long_integer_type_node.",
5866 tree, (void),
5867 default_cxx_guard_type)
5869 /* Return true if only the low bit of the guard should be tested. */
5870 DEFHOOK
5871 (guard_mask_bit,
5872 "This hook determines how guard variables are used. It should return\n\
5873 @code{false} (the default) if the first byte should be used. A return value of\n\
5874 @code{true} indicates that only the least significant bit should be used.",
5875 bool, (void),
5876 hook_bool_void_false)
5878 /* Returns the size of the array cookie for an array of type. */
5879 DEFHOOK
5880 (get_cookie_size,
5881 "This hook returns the size of the cookie to use when allocating an array\n\
5882 whose elements have the indicated @var{type}. Assumes that it is already\n\
5883 known that a cookie is needed. The default is\n\
5884 @code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the\n\
5885 IA64/Generic C++ ABI@.",
5886 tree, (tree type),
5887 default_cxx_get_cookie_size)
5889 /* Returns true if the element size should be stored in the array cookie. */
5890 DEFHOOK
5891 (cookie_has_size,
5892 "This hook should return @code{true} if the element size should be stored in\n\
5893 array cookies. The default is to return @code{false}.",
5894 bool, (void),
5895 hook_bool_void_false)
5897 /* Allows backends to perform additional processing when
5898 deciding if a class should be exported or imported. */
5899 DEFHOOK
5900 (import_export_class,
5901 "If defined by a backend this hook allows the decision made to export\n\
5902 class @var{type} to be overruled. Upon entry @var{import_export}\n\
5903 will contain 1 if the class is going to be exported, @minus{}1 if it is going\n\
5904 to be imported and 0 otherwise. This function should return the\n\
5905 modified value and perform any other actions necessary to support the\n\
5906 backend's targeted operating system.",
5907 int, (tree type, int import_export), NULL)
5909 /* Returns true if constructors and destructors return "this". */
5910 DEFHOOK
5911 (cdtor_returns_this,
5912 "This hook should return @code{true} if constructors and destructors return\n\
5913 the address of the object created/destroyed. The default is to return\n\
5914 @code{false}.",
5915 bool, (void),
5916 hook_bool_void_false)
5918 /* Returns true if the key method for a class can be an inline
5919 function, so long as it is not declared inline in the class
5920 itself. Returning true is the behavior required by the Itanium C++ ABI. */
5921 DEFHOOK
5922 (key_method_may_be_inline,
5923 "This hook returns true if the key method for a class (i.e., the method\n\
5924 which, if defined in the current translation unit, causes the virtual\n\
5925 table to be emitted) may be an inline function. Under the standard\n\
5926 Itanium C++ ABI the key method may be an inline function so long as\n\
5927 the function is not declared inline in the class definition. Under\n\
5928 some variants of the ABI, an inline function can never be the key\n\
5929 method. The default is to return @code{true}.",
5930 bool, (void),
5931 hook_bool_void_true)
5933 DEFHOOK
5934 (determine_class_data_visibility,
5935 "@var{decl} is a virtual table, virtual table table, typeinfo object,\
5936 or other similar implicit class data object that will be emitted with\
5937 external linkage in this translation unit. No ELF visibility has been\
5938 explicitly specified. If the target needs to specify a visibility\
5939 other than that of the containing class, use this hook to set\
5940 @code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
5941 void, (tree decl),
5942 hook_void_tree)
5944 /* Returns true (the default) if virtual tables and other
5945 similar implicit class data objects are always COMDAT if they
5946 have external linkage. If this hook returns false, then
5947 class data for classes whose virtual table will be emitted in
5948 only one translation unit will not be COMDAT. */
5949 DEFHOOK
5950 (class_data_always_comdat,
5951 "This hook returns true (the default) if virtual tables and other\n\
5952 similar implicit class data objects are always COMDAT if they have\n\
5953 external linkage. If this hook returns false, then class data for\n\
5954 classes whose virtual table will be emitted in only one translation\n\
5955 unit will not be COMDAT.",
5956 bool, (void),
5957 hook_bool_void_true)
5959 /* Returns true (the default) if the RTTI for the basic types,
5960 which is always defined in the C++ runtime, should be COMDAT;
5961 false if it should not be COMDAT. */
5962 DEFHOOK
5963 (library_rtti_comdat,
5964 "This hook returns true (the default) if the RTTI information for\n\
5965 the basic types which is defined in the C++ runtime should always\n\
5966 be COMDAT, false if it should not be COMDAT.",
5967 bool, (void),
5968 hook_bool_void_true)
5970 /* Returns true if __aeabi_atexit should be used to register static
5971 destructors. */
5972 DEFHOOK
5973 (use_aeabi_atexit,
5974 "This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)\n\
5975 should be used to register static destructors when @option{-fuse-cxa-atexit}\n\
5976 is in effect. The default is to return false to use @code{__cxa_atexit}.",
5977 bool, (void),
5978 hook_bool_void_false)
5980 /* Returns true if target may use atexit in the same manner as
5981 __cxa_atexit to register static destructors. */
5982 DEFHOOK
5983 (use_atexit_for_cxa_atexit,
5984 "This hook returns true if the target @code{atexit} function can be used\n\
5985 in the same manner as @code{__cxa_atexit} to register C++ static\n\
5986 destructors. This requires that @code{atexit}-registered functions in\n\
5987 shared libraries are run in the correct order when the libraries are\n\
5988 unloaded. The default is to return false.",
5989 bool, (void),
5990 hook_bool_void_false)
5992 DEFHOOK
5993 (adjust_class_at_definition,
5994 "@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\
5995 been defined. Use this hook to make adjustments to the class (eg, tweak\
5996 visibility or perform any other required target modifications).",
5997 void, (tree type),
5998 hook_void_tree)
6000 DEFHOOK
6001 (decl_mangling_context,
6002 "Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
6003 tree, (const_tree decl),
6004 hook_tree_const_tree_null)
6006 HOOK_VECTOR_END (cxx)
6008 /* Functions and data for emulated TLS support. */
6009 #undef HOOK_PREFIX
6010 #define HOOK_PREFIX "TARGET_EMUTLS_"
6011 HOOK_VECTOR (TARGET_EMUTLS, emutls)
6013 /* Name of the address and common functions. */
6014 DEFHOOKPOD
6015 (get_address,
6016 "Contains the name of the helper function that uses a TLS control\n\
6017 object to locate a TLS instance. The default causes libgcc's\n\
6018 emulated TLS helper function to be used.",
6019 const char *, "__builtin___emutls_get_address")
6021 DEFHOOKPOD
6022 (register_common,
6023 "Contains the name of the helper function that should be used at\n\
6024 program startup to register TLS objects that are implicitly\n\
6025 initialized to zero. If this is @code{NULL}, all TLS objects will\n\
6026 have explicit initializers. The default causes libgcc's emulated TLS\n\
6027 registration function to be used.",
6028 const char *, "__builtin___emutls_register_common")
6030 /* Prefixes for proxy variable and template. */
6031 DEFHOOKPOD
6032 (var_section,
6033 "Contains the name of the section in which TLS control variables should\n\
6034 be placed. The default of @code{NULL} allows these to be placed in\n\
6035 any section.",
6036 const char *, NULL)
6038 DEFHOOKPOD
6039 (tmpl_section,
6040 "Contains the name of the section in which TLS initializers should be\n\
6041 placed. The default of @code{NULL} allows these to be placed in any\n\
6042 section.",
6043 const char *, NULL)
6045 /* Prefixes for proxy variable and template. */
6046 DEFHOOKPOD
6047 (var_prefix,
6048 "Contains the prefix to be prepended to TLS control variable names.\n\
6049 The default of @code{NULL} uses a target-specific prefix.",
6050 const char *, NULL)
6052 DEFHOOKPOD
6053 (tmpl_prefix,
6054 "Contains the prefix to be prepended to TLS initializer objects. The\n\
6055 default of @code{NULL} uses a target-specific prefix.",
6056 const char *, NULL)
6058 /* Function to generate field definitions of the proxy variable. */
6059 DEFHOOK
6060 (var_fields,
6061 "Specifies a function that generates the FIELD_DECLs for a TLS control\n\
6062 object type. @var{type} is the RECORD_TYPE the fields are for and\n\
6063 @var{name} should be filled with the structure tag, if the default of\n\
6064 @code{__emutls_object} is unsuitable. The default creates a type suitable\n\
6065 for libgcc's emulated TLS function.",
6066 tree, (tree type, tree *name),
6067 default_emutls_var_fields)
6069 /* Function to initialize a proxy variable. */
6070 DEFHOOK
6071 (var_init,
6072 "Specifies a function that generates the CONSTRUCTOR to initialize a\n\
6073 TLS control object. @var{var} is the TLS control object, @var{decl}\n\
6074 is the TLS object and @var{tmpl_addr} is the address of the\n\
6075 initializer. The default initializes libgcc's emulated TLS control object.",
6076 tree, (tree var, tree decl, tree tmpl_addr),
6077 default_emutls_var_init)
6079 /* Whether we are allowed to alter the usual alignment of the
6080 proxy variable. */
6081 DEFHOOKPOD
6082 (var_align_fixed,
6083 "Specifies whether the alignment of TLS control variable objects is\n\
6084 fixed and should not be increased as some backends may do to optimize\n\
6085 single objects. The default is false.",
6086 bool, false)
6088 /* Whether we can emit debug information for TLS vars. */
6089 DEFHOOKPOD
6090 (debug_form_tls_address,
6091 "Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor\n\
6092 may be used to describe emulated TLS control objects.",
6093 bool, false)
6095 HOOK_VECTOR_END (emutls)
6097 #undef HOOK_PREFIX
6098 #define HOOK_PREFIX "TARGET_OPTION_"
6099 HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)
6101 /* Function to validate the attribute((target(...))) strings. If
6102 the option is validated, the hook should also fill in
6103 DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
6104 DEFHOOK
6105 (valid_attribute_p,
6106 "This hook is called to parse @code{attribute(target(\"...\"))}, which\n\
6107 allows setting target-specific options on individual functions.\n\
6108 These function-specific options may differ\n\
6109 from the options specified on the command line. The hook should return\n\
6110 @code{true} if the options are valid.\n\
6112 The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
6113 the function declaration to hold a pointer to a target-specific\n\
6114 @code{struct cl_target_option} structure.",
6115 bool, (tree fndecl, tree name, tree args, int flags),
6116 default_target_option_valid_attribute_p)
6118 /* Function to save any extra target state in the target options structure. */
6119 DEFHOOK
6120 (save,
6121 "This hook is called to save any additional target-specific information\n\
6122 in the @code{struct cl_target_option} structure for function-specific\n\
6123 options from the @code{struct gcc_options} structure.\n\
6124 @xref{Option file format}.",
6125 void, (struct cl_target_option *ptr, struct gcc_options *opts), NULL)
6127 /* Function to restore any extra target state from the target options
6128 structure. */
6129 DEFHOOK
6130 (restore,
6131 "This hook is called to restore any additional target-specific\n\
6132 information in the @code{struct cl_target_option} structure for\n\
6133 function-specific options to the @code{struct gcc_options} structure.",
6134 void, (struct gcc_options *opts, struct cl_target_option *ptr), NULL)
6136 /* Function to update target-specific option information after being
6137 streamed in. */
6138 DEFHOOK
6139 (post_stream_in,
6140 "This hook is called to update target-specific information in the\n\
6141 @code{struct cl_target_option} structure after it is streamed in from\n\
6142 LTO bytecode.",
6143 void, (struct cl_target_option *ptr), NULL)
6145 /* Function to print any extra target state from the target options
6146 structure. */
6147 DEFHOOK
6148 (print,
6149 "This hook is called to print any additional target-specific\n\
6150 information in the @code{struct cl_target_option} structure for\n\
6151 function-specific options.",
6152 void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)
6154 /* Function to parse arguments to be validated for #pragma target, and to
6155 change the state if the options are valid. If the first argument is
6156 NULL, the second argument specifies the default options to use. Return
6157 true if the options are valid, and set the current state. */
6158 DEFHOOK
6159 (pragma_parse,
6160 "This target hook parses the options for @code{#pragma GCC target}, which\n\
6161 sets the target-specific options for functions that occur later in the\n\
6162 input stream. The options accepted should be the same as those handled by the\n\
6163 @code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.",
6164 bool, (tree args, tree pop_target),
6165 default_target_option_pragma_parse)
6167 /* Do option overrides for the target. */
6168 DEFHOOK
6169 (override,
6170 "Sometimes certain combinations of command options do not make sense on\n\
6171 a particular target machine. You can override the hook\n\
6172 @code{TARGET_OPTION_OVERRIDE} to take account of this. This hooks is called\n\
6173 once just after all the command options have been parsed.\n\
6175 Don't use this hook to turn on various extra optimizations for\n\
6176 @option{-O}. That is what @code{TARGET_OPTION_OPTIMIZATION} is for.\n\
6178 If you need to do something whenever the optimization level is\n\
6179 changed via the optimize attribute or pragma, see\n\
6180 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}",
6181 void, (void),
6182 hook_void_void)
6184 /* This function returns true if DECL1 and DECL2 are versions of the same
6185 function. DECL1 and DECL2 are function versions if and only if they
6186 have the same function signature and different target specific attributes,
6187 that is, they are compiled for different target machines. */
6188 DEFHOOK
6189 (function_versions,
6190 "This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are\n\
6191 versions of the same function. @var{DECL1} and @var{DECL2} are function\n\
6192 versions if and only if they have the same function signature and\n\
6193 different target specific attributes, that is, they are compiled for\n\
6194 different target machines.",
6195 bool, (tree decl1, tree decl2),
6196 hook_bool_tree_tree_false)
6198 /* Function to determine if one function can inline another function. */
6199 #undef HOOK_PREFIX
6200 #define HOOK_PREFIX "TARGET_"
6201 DEFHOOK
6202 (can_inline_p,
6203 "This target hook returns @code{false} if the @var{caller} function\n\
6204 cannot inline @var{callee}, based on target specific information. By\n\
6205 default, inlining is not allowed if the callee function has function\n\
6206 specific target options and the caller does not use the same options.",
6207 bool, (tree caller, tree callee),
6208 default_target_can_inline_p)
6210 DEFHOOK
6211 (relayout_function,
6212 "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.",
6213 void, (tree fndecl),
6214 hook_void_tree)
6216 HOOK_VECTOR_END (target_option)
6218 /* For targets that need to mark extra registers as live on entry to
6219 the function, they should define this target hook and set their
6220 bits in the bitmap passed in. */
6221 DEFHOOK
6222 (extra_live_on_entry,
6223 "Add any hard registers to @var{regs} that are live on entry to the\n\
6224 function. This hook only needs to be defined to provide registers that\n\
6225 cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved\n\
6226 registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,\n\
6227 TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,\n\
6228 FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.",
6229 void, (bitmap regs),
6230 hook_void_bitmap)
6232 /* Targets should define this target hook to mark that non-callee clobbers are
6233 present in CALL_INSN_FUNCTION_USAGE for all the calls that bind to a local
6234 definition. */
6235 DEFHOOKPOD
6236 (call_fusage_contains_non_callee_clobbers,
6237 "Set to true if each call that binds to a local definition explicitly\n\
6238 clobbers or sets all non-fixed registers modified by performing the call.\n\
6239 That is, by the call pattern itself, or by code that might be inserted by the\n\
6240 linker (e.g. stubs, veneers, branch islands), but not including those\n\
6241 modifiable by the callee. The affected registers may be mentioned explicitly\n\
6242 in the call pattern, or included as clobbers in CALL_INSN_FUNCTION_USAGE.\n\
6243 The default version of this hook is set to false. The purpose of this hook\n\
6244 is to enable the fipa-ra optimization.",
6245 bool,
6246 false)
6248 /* Fill in additional registers set up by prologue into a regset. */
6249 DEFHOOK
6250 (set_up_by_prologue,
6251 "This hook should add additional registers that are computed by the prologue\
6252 to the hard regset for shrink-wrapping optimization purposes.",
6253 void, (struct hard_reg_set_container *),
6254 NULL)
6256 /* For targets that have attributes that can affect whether a
6257 function's return statements need checking. For instance a 'naked'
6258 function attribute. */
6259 DEFHOOK
6260 (warn_func_return,
6261 "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.",
6262 bool, (tree),
6263 hook_bool_tree_true)
6265 #undef HOOK_PREFIX
6266 #define HOOK_PREFIX "TARGET_SHRINK_WRAP_"
6267 HOOK_VECTOR (TARGET_SHRINK_WRAP_HOOKS, shrink_wrap)
6269 DEFHOOK
6270 (get_separate_components,
6271 "This hook should return an @code{sbitmap} with the bits set for those\n\
6272 components that can be separately shrink-wrapped in the current function.\n\
6273 Return @code{NULL} if the current function should not get any separate\n\
6274 shrink-wrapping.\n\
6275 Don't define this hook if it would always return @code{NULL}.\n\
6276 If it is defined, the other hooks in this group have to be defined as well.",
6277 sbitmap, (void),
6278 NULL)
6280 DEFHOOK
6281 (components_for_bb,
6282 "This hook should return an @code{sbitmap} with the bits set for those\n\
6283 components where either the prologue component has to be executed before\n\
6284 the @code{basic_block}, or the epilogue component after it, or both.",
6285 sbitmap, (basic_block),
6286 NULL)
6288 DEFHOOK
6289 (disqualify_components,
6290 "This hook should clear the bits in the @var{components} bitmap for those\n\
6291 components in @var{edge_components} that the target cannot handle on edge\n\
6292 @var{e}, where @var{is_prologue} says if this is for a prologue or an\n\
6293 epilogue instead.",
6294 void, (sbitmap components, edge e, sbitmap edge_components, bool is_prologue),
6295 NULL)
6297 DEFHOOK
6298 (emit_prologue_components,
6299 "Emit prologue insns for the components indicated by the parameter.",
6300 void, (sbitmap),
6301 NULL)
6303 DEFHOOK
6304 (emit_epilogue_components,
6305 "Emit epilogue insns for the components indicated by the parameter.",
6306 void, (sbitmap),
6307 NULL)
6309 DEFHOOK
6310 (set_handled_components,
6311 "Mark the components in the parameter as handled, so that the\n\
6312 @code{prologue} and @code{epilogue} named patterns know to ignore those\n\
6313 components. The target code should not hang on to the @code{sbitmap}, it\n\
6314 will be deleted after this call.",
6315 void, (sbitmap),
6316 NULL)
6318 HOOK_VECTOR_END (shrink_wrap)
6319 #undef HOOK_PREFIX
6320 #define HOOK_PREFIX "TARGET_"
6322 /* Determine the type of unwind info to emit for debugging. */
6323 DEFHOOK
6324 (debug_unwind_info,
6325 "This hook defines the mechanism that will be used for describing frame\n\
6326 unwind information to the debugger. Normally the hook will return\n\
6327 @code{UI_DWARF2} if DWARF 2 debug information is enabled, and\n\
6328 return @code{UI_NONE} otherwise.\n\
6330 A target may return @code{UI_DWARF2} even when DWARF 2 debug information\n\
6331 is disabled in order to always output DWARF 2 frame information.\n\
6333 A target may return @code{UI_TARGET} if it has ABI specified unwind tables.\n\
6334 This will suppress generation of the normal debug frame unwind information.",
6335 enum unwind_info_type, (void),
6336 default_debug_unwind_info)
6338 /* The code parameter should be of type enum rtx_code but this is not
6339 defined at this time. */
6340 DEFHOOK
6341 (canonicalize_comparison,
6342 "On some machines not all possible comparisons are defined, but you can\n\
6343 convert an invalid comparison into a valid one. For example, the Alpha\n\
6344 does not have a @code{GT} comparison, but you can use an @code{LT}\n\
6345 comparison instead and swap the order of the operands.\n\
6347 On such machines, implement this hook to do any required conversions.\n\
6348 @var{code} is the initial comparison code and @var{op0} and @var{op1}\n\
6349 are the left and right operands of the comparison, respectively. If\n\
6350 @var{op0_preserve_value} is @code{true} the implementation is not\n\
6351 allowed to change the value of @var{op0} since the value might be used\n\
6352 in RTXs which aren't comparisons. E.g. the implementation is not\n\
6353 allowed to swap operands in that case.\n\
6355 GCC will not assume that the comparison resulting from this macro is\n\
6356 valid but will see if the resulting insn matches a pattern in the\n\
6357 @file{md} file.\n\
6359 You need not to implement this hook if it would never change the\n\
6360 comparison code or operands.",
6361 void, (int *code, rtx *op0, rtx *op1, bool op0_preserve_value),
6362 default_canonicalize_comparison)
6364 DEFHOOK
6365 (min_arithmetic_precision,
6366 "On some RISC architectures with 64-bit registers, the processor also\n\
6367 maintains 32-bit condition codes that make it possible to do real 32-bit\n\
6368 arithmetic, although the operations are performed on the full registers.\n\
6370 On such architectures, defining this hook to 32 tells the compiler to try\n\
6371 using 32-bit arithmetical operations setting the condition codes instead\n\
6372 of doing full 64-bit arithmetic.\n\
6374 More generally, define this hook on RISC architectures if you want the\n\
6375 compiler to try using arithmetical operations setting the condition codes\n\
6376 with a precision lower than the word precision.\n\
6378 You need not define this hook if @code{WORD_REGISTER_OPERATIONS} is not\n\
6379 defined to 1.",
6380 unsigned int, (void), default_min_arithmetic_precision)
6382 DEFHOOKPOD
6383 (atomic_test_and_set_trueval,
6384 "This value should be set if the result written by\
6385 @code{atomic_test_and_set} is not exactly 1, i.e. the\
6386 @code{bool} @code{true}.",
6387 unsigned char, 1)
6389 /* Return an unsigned int representing the alignment (in bits) of the atomic
6390 type which maps to machine MODE. This allows alignment to be overridden
6391 as needed. */
6392 DEFHOOK
6393 (atomic_align_for_mode,
6394 "If defined, this function returns an appropriate alignment in bits for an\
6395 atomic object of machine_mode @var{mode}. If 0 is returned then the\
6396 default alignment for the specified mode is used. ",
6397 unsigned int, (machine_mode mode),
6398 hook_uint_mode_0)
6400 DEFHOOK
6401 (atomic_assign_expand_fenv,
6402 "ISO C11 requires atomic compound assignments that may raise floating-point\
6403 exceptions to raise exceptions corresponding to the arithmetic operation\
6404 whose result was successfully stored in a compare-and-exchange sequence. \
6405 This requires code equivalent to calls to @code{feholdexcept},\
6406 @code{feclearexcept} and @code{feupdateenv} to be generated at\
6407 appropriate points in the compare-and-exchange sequence. This hook should\
6408 set @code{*@var{hold}} to an expression equivalent to the call to\
6409 @code{feholdexcept}, @code{*@var{clear}} to an expression equivalent to\
6410 the call to @code{feclearexcept} and @code{*@var{update}} to an expression\
6411 equivalent to the call to @code{feupdateenv}. The three expressions are\
6412 @code{NULL_TREE} on entry to the hook and may be left as @code{NULL_TREE}\
6413 if no code is required in a particular place. The default implementation\
6414 leaves all three expressions as @code{NULL_TREE}. The\
6415 @code{__atomic_feraiseexcept} function from @code{libatomic} may be of use\
6416 as part of the code generated in @code{*@var{update}}.",
6417 void, (tree *hold, tree *clear, tree *update),
6418 default_atomic_assign_expand_fenv)
6420 /* Leave the boolean fields at the end. */
6422 /* True if we can create zeroed data by switching to a BSS section
6423 and then using ASM_OUTPUT_SKIP to allocate the space. */
6424 DEFHOOKPOD
6425 (have_switchable_bss_sections,
6426 "This flag is true if we can create zeroed data by switching to a BSS\n\
6427 section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.\n\
6428 This is true on most ELF targets.",
6429 bool, false)
6431 /* True if "native" constructors and destructors are supported,
6432 false if we're using collect2 for the job. */
6433 DEFHOOKPOD
6434 (have_ctors_dtors,
6435 "This value is true if the target supports some ``native'' method of\n\
6436 collecting constructors and destructors to be run at startup and exit.\n\
6437 It is false if we must use @command{collect2}.",
6438 bool, false)
6440 /* True if thread-local storage is supported. */
6441 DEFHOOKPOD
6442 (have_tls,
6443 "Contains the value true if the target supports thread-local storage.\n\
6444 The default value is false.",
6445 bool, false)
6447 /* True if a small readonly data section is supported. */
6448 DEFHOOKPOD
6449 (have_srodata_section,
6450 "Contains the value true if the target places read-only\n\
6451 ``small data'' into a separate section. The default value is false.",
6452 bool, false)
6454 /* True if EH frame info sections should be zero-terminated. */
6455 DEFHOOKPOD
6456 (terminate_dw2_eh_frame_info,
6457 "Contains the value true if the target should add a zero word onto the\n\
6458 end of a Dwarf-2 frame info section when used for exception handling.\n\
6459 Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and\n\
6460 true otherwise.",
6461 bool, true)
6463 /* True if #NO_APP should be emitted at the beginning of assembly output. */
6464 DEFHOOKPOD
6465 (asm_file_start_app_off,
6466 "If this flag is true, the text of the macro @code{ASM_APP_OFF} will be\n\
6467 printed as the very first line in the assembly file, unless\n\
6468 @option{-fverbose-asm} is in effect. (If that macro has been defined\n\
6469 to the empty string, this variable has no effect.) With the normal\n\
6470 definition of @code{ASM_APP_OFF}, the effect is to notify the GNU\n\
6471 assembler that it need not bother stripping comments or extra\n\
6472 whitespace from its input. This allows it to work a bit faster.\n\
6474 The default is false. You should not set it to true unless you have\n\
6475 verified that your port does not generate any extra whitespace or\n\
6476 comments that will cause GAS to issue errors in NO_APP mode.",
6477 bool, false)
6479 /* True if output_file_directive should be called for main_input_filename
6480 at the beginning of assembly output. */
6481 DEFHOOKPOD
6482 (asm_file_start_file_directive,
6483 "If this flag is true, @code{output_file_directive} will be called\n\
6484 for the primary source file, immediately after printing\n\
6485 @code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect\n\
6486 this to be done. The default is false.",
6487 bool, false)
6489 /* Returns true if we should generate exception tables for use with the
6490 ARM EABI. The effects the encoding of function exception specifications. */
6491 DEFHOOKPOD
6492 (arm_eabi_unwinder,
6493 "This flag should be set to @code{true} on targets that use an ARM EABI\n\
6494 based unwinding library, and @code{false} on other targets. This effects\n\
6495 the format of unwinding tables, and how the unwinder in entered after\n\
6496 running a cleanup. The default is @code{false}.",
6497 bool, false)
6499 DEFHOOKPOD
6500 (want_debug_pub_sections,
6501 "True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\
6502 should be emitted. These sections are not used on most platforms, and\
6503 in particular GDB does not use them.",
6504 bool, false)
6506 DEFHOOKPOD
6507 (delay_sched2, "True if sched2 is not to be run at its normal place.\n\
6508 This usually means it will be run as part of machine-specific reorg.",
6509 bool, false)
6511 DEFHOOKPOD
6512 (delay_vartrack, "True if vartrack is not to be run at its normal place.\n\
6513 This usually means it will be run as part of machine-specific reorg.",
6514 bool, false)
6516 DEFHOOKPOD
6517 (no_register_allocation, "True if register allocation and the passes\n\
6518 following it should not be run. Usually true only for virtual assembler\n\
6519 targets.",
6520 bool, false)
6522 /* Leave the boolean fields at the end. */
6524 /* Functions related to mode switching. */
6525 #undef HOOK_PREFIX
6526 #define HOOK_PREFIX "TARGET_MODE_"
6527 HOOK_VECTOR (TARGET_TOGGLE_, mode_switching)
6529 DEFHOOK
6530 (emit,
6531 "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.",
6532 void, (int entity, int mode, int prev_mode, HARD_REG_SET regs_live), NULL)
6534 DEFHOOK
6535 (needed,
6536 "@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}.",
6537 int, (int entity, rtx_insn *insn), NULL)
6539 DEFHOOK
6540 (after,
6541 "@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).",
6542 int, (int entity, int mode, rtx_insn *insn), NULL)
6544 DEFHOOK
6545 (entry,
6546 "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.",
6547 int, (int entity), NULL)
6549 DEFHOOK
6550 (exit,
6551 "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.",
6552 int, (int entity), NULL)
6554 DEFHOOK
6555 (priority,
6556 "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}.",
6557 int, (int entity, int n), NULL)
6559 HOOK_VECTOR_END (mode_switching)
6561 #undef HOOK_PREFIX
6562 #define HOOK_PREFIX "TARGET_"
6564 #define DEF_TARGET_INSN(NAME, PROTO) \
6565 DEFHOOK_UNDOC (have_##NAME, "", bool, (void), false)
6566 #include "target-insns.def"
6567 #undef DEF_TARGET_INSN
6569 #define DEF_TARGET_INSN(NAME, PROTO) \
6570 DEFHOOK_UNDOC (gen_##NAME, "", rtx_insn *, PROTO, NULL)
6571 #include "target-insns.def"
6572 #undef DEF_TARGET_INSN
6574 #define DEF_TARGET_INSN(NAME, PROTO) \
6575 DEFHOOKPOD (code_for_##NAME, "*", enum insn_code, CODE_FOR_nothing)
6576 #include "target-insns.def"
6577 #undef DEF_TARGET_INSN
6579 DEFHOOK
6580 (run_target_selftests,
6581 "If selftests are enabled, run any selftests for this target.",
6582 void, (void),
6583 NULL)
6585 /* Close the 'struct gcc_target' definition. */
6586 HOOK_VECTOR_END (C90_EMPTY_HACK)