* gcc.dg/store-motion-fgcse-sm.c (dg-final): Cleanup
[official-gcc.git] / gcc / target.def
blobdc48ae6912e920198516f6580f161fc3bfcd9a10
1 /* Target hook definitions.
2 Copyright (C) 2001-2014 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 /* Output the assembler code for entry to a function. */
292 DEFHOOK
293 (function_prologue,
294 "If defined, a function that outputs the assembler code for entry to a\n\
295 function. The prologue is responsible for setting up the stack frame,\n\
296 initializing the frame pointer register, saving registers that must be\n\
297 saved, and allocating @var{size} additional bytes of storage for the\n\
298 local variables. @var{size} is an integer. @var{file} is a stdio\n\
299 stream to which the assembler code should be output.\n\
301 The label for the beginning of the function need not be output by this\n\
302 macro. That has already been done when the macro is run.\n\
304 @findex regs_ever_live\n\
305 To determine which registers to save, the macro can refer to the array\n\
306 @code{regs_ever_live}: element @var{r} is nonzero if hard register\n\
307 @var{r} is used anywhere within the function. This implies the function\n\
308 prologue should save register @var{r}, provided it is not one of the\n\
309 call-used registers. (@code{TARGET_ASM_FUNCTION_EPILOGUE} must likewise use\n\
310 @code{regs_ever_live}.)\n\
312 On machines that have ``register windows'', the function entry code does\n\
313 not save on the stack the registers that are in the windows, even if\n\
314 they are supposed to be preserved by function calls; instead it takes\n\
315 appropriate steps to ``push'' the register stack, if any non-call-used\n\
316 registers are used in the function.\n\
318 @findex frame_pointer_needed\n\
319 On machines where functions may or may not have frame-pointers, the\n\
320 function entry code must vary accordingly; it must set up the frame\n\
321 pointer if one is wanted, and not otherwise. To determine whether a\n\
322 frame pointer is in wanted, the macro can refer to the variable\n\
323 @code{frame_pointer_needed}. The variable's value will be 1 at run\n\
324 time in a function that needs a frame pointer. @xref{Elimination}.\n\
326 The function entry code is responsible for allocating any stack space\n\
327 required for the function. This stack space consists of the regions\n\
328 listed below. In most cases, these regions are allocated in the\n\
329 order listed, with the last listed region closest to the top of the\n\
330 stack (the lowest address if @code{STACK_GROWS_DOWNWARD} is defined, and\n\
331 the highest address if it is not defined). You can use a different order\n\
332 for a machine if doing so is more convenient or required for\n\
333 compatibility reasons. Except in cases where required by standard\n\
334 or by a debugger, there is no reason why the stack layout used by GCC\n\
335 need agree with that used by other compilers for a machine.",
336 void, (FILE *file, HOST_WIDE_INT size),
337 default_function_pro_epilogue)
339 /* Output the assembler code for end of prologue. */
340 DEFHOOK
341 (function_end_prologue,
342 "If defined, a function that outputs assembler code at the end of a\n\
343 prologue. This should be used when the function prologue is being\n\
344 emitted as RTL, and you have some extra assembler that needs to be\n\
345 emitted. @xref{prologue instruction pattern}.",
346 void, (FILE *file),
347 no_asm_to_stream)
349 /* Output the assembler code for start of epilogue. */
350 DEFHOOK
351 (function_begin_epilogue,
352 "If defined, a function that outputs assembler code at the start of an\n\
353 epilogue. This should be used when the function epilogue is being\n\
354 emitted as RTL, and you have some extra assembler that needs to be\n\
355 emitted. @xref{epilogue instruction pattern}.",
356 void, (FILE *file),
357 no_asm_to_stream)
359 /* Output the assembler code for function exit. */
360 DEFHOOK
361 (function_epilogue,
362 "If defined, a function that outputs the assembler code for exit from a\n\
363 function. The epilogue is responsible for restoring the saved\n\
364 registers and stack pointer to their values when the function was\n\
365 called, and returning control to the caller. This macro takes the\n\
366 same arguments as the macro @code{TARGET_ASM_FUNCTION_PROLOGUE}, and the\n\
367 registers to restore are determined from @code{regs_ever_live} and\n\
368 @code{CALL_USED_REGISTERS} in the same way.\n\
370 On some machines, there is a single instruction that does all the work\n\
371 of returning from the function. On these machines, give that\n\
372 instruction the name @samp{return} and do not define the macro\n\
373 @code{TARGET_ASM_FUNCTION_EPILOGUE} at all.\n\
375 Do not define a pattern named @samp{return} if you want the\n\
376 @code{TARGET_ASM_FUNCTION_EPILOGUE} to be used. If you want the target\n\
377 switches to control whether return instructions or epilogues are used,\n\
378 define a @samp{return} pattern with a validity condition that tests the\n\
379 target switches appropriately. If the @samp{return} pattern's validity\n\
380 condition is false, epilogues will be used.\n\
382 On machines where functions may or may not have frame-pointers, the\n\
383 function exit code must vary accordingly. Sometimes the code for these\n\
384 two cases is completely different. To determine whether a frame pointer\n\
385 is wanted, the macro can refer to the variable\n\
386 @code{frame_pointer_needed}. The variable's value will be 1 when compiling\n\
387 a function that needs a frame pointer.\n\
389 Normally, @code{TARGET_ASM_FUNCTION_PROLOGUE} and\n\
390 @code{TARGET_ASM_FUNCTION_EPILOGUE} must treat leaf functions specially.\n\
391 The C variable @code{current_function_is_leaf} is nonzero for such a\n\
392 function. @xref{Leaf Functions}.\n\
394 On some machines, some functions pop their arguments on exit while\n\
395 others leave that for the caller to do. For example, the 68020 when\n\
396 given @option{-mrtd} pops arguments in functions that take a fixed\n\
397 number of arguments.\n\
399 @findex pops_args\n\
400 @findex crtl->args.pops_args\n\
401 Your definition of the macro @code{RETURN_POPS_ARGS} decides which\n\
402 functions pop their own arguments. @code{TARGET_ASM_FUNCTION_EPILOGUE}\n\
403 needs to know what was decided. The number of bytes of the current\n\
404 function's arguments that this function should pop is available in\n\
405 @code{crtl->args.pops_args}. @xref{Scalar Return}.",
406 void, (FILE *file, HOST_WIDE_INT size),
407 default_function_pro_epilogue)
409 /* Initialize target-specific sections. */
410 DEFHOOK
411 (init_sections,
412 "Define this hook if you need to do something special to set up the\n\
413 @file{varasm.c} sections, or if your target has some special sections\n\
414 of its own that you need to create.\n\
416 GCC calls this hook after processing the command line, but before writing\n\
417 any assembly code, and before calling any of the section-returning hooks\n\
418 described below.",
419 void, (void),
420 hook_void_void)
422 /* Tell assembler to change to section NAME with attributes FLAGS.
423 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
424 which this section is associated. */
425 DEFHOOK
426 (named_section,
427 "Output assembly directives to switch to section @var{name}. The section\n\
428 should have attributes as specified by @var{flags}, which is a bit mask\n\
429 of the @code{SECTION_*} flags defined in @file{output.h}. If @var{decl}\n\
430 is non-NULL, it is the @code{VAR_DECL} or @code{FUNCTION_DECL} with which\n\
431 this section is associated.",
432 void, (const char *name, unsigned int flags, tree decl),
433 default_no_named_section)
435 /* Return preferred text (sub)section for function DECL.
436 Main purpose of this function is to separate cold, normal and hot
437 functions. STARTUP is true when function is known to be used only
438 at startup (from static constructors or it is main()).
439 EXIT is true when function is known to be used only at exit
440 (from static destructors).
441 Return NULL if function should go to default text section. */
442 DEFHOOK
443 (function_section,
444 "Return preferred text (sub)section for function @var{decl}.\n\
445 Main purpose of this function is to separate cold, normal and hot\n\
446 functions. @var{startup} is true when function is known to be used only\n\
447 at startup (from static constructors or it is @code{main()}).\n\
448 @var{exit} is true when function is known to be used only at exit\n\
449 (from static destructors).\n\
450 Return NULL if function should go to default text section.",
451 section *, (tree decl, enum node_frequency freq, bool startup, bool exit),
452 default_function_section)
454 /* Output the assembler code for function exit. */
455 DEFHOOK
456 (function_switched_text_sections,
457 "Used by the target to emit any assembler directives or additional\
458 labels needed when a function is partitioned between different\
459 sections. Output should be written to @var{file}. The function\
460 decl is available as @var{decl} and the new section is `cold' if\
461 @var{new_is_cold} is @code{true}.",
462 void, (FILE *file, tree decl, bool new_is_cold),
463 default_function_switched_text_sections)
465 /* Return a mask describing how relocations should be treated when
466 selecting sections. Bit 1 should be set if global relocations
467 should be placed in a read-write section; bit 0 should be set if
468 local relocations should be placed in a read-write section. */
469 DEFHOOK
470 (reloc_rw_mask,
471 "Return a mask describing how relocations should be treated when\n\
472 selecting sections. Bit 1 should be set if global relocations\n\
473 should be placed in a read-write section; bit 0 should be set if\n\
474 local relocations should be placed in a read-write section.\n\
476 The default version of this function returns 3 when @option{-fpic}\n\
477 is in effect, and 0 otherwise. The hook is typically redefined\n\
478 when the target cannot support (some kinds of) dynamic relocations\n\
479 in read-only sections even in executables.",
480 int, (void),
481 default_reloc_rw_mask)
483 /* Return a section for EXP. It may be a DECL or a constant. RELOC
484 is nonzero if runtime relocations must be applied; bit 1 will be
485 set if the runtime relocations require non-local name resolution.
486 ALIGN is the required alignment of the data. */
487 DEFHOOK
488 (select_section,
489 "Return the section into which @var{exp} should be placed. You can\n\
490 assume that @var{exp} is either a @code{VAR_DECL} node or a constant of\n\
491 some sort. @var{reloc} indicates whether the initial value of @var{exp}\n\
492 requires link-time relocations. Bit 0 is set when variable contains\n\
493 local relocations only, while bit 1 is set for global relocations.\n\
494 @var{align} is the constant alignment in bits.\n\
496 The default version of this function takes care of putting read-only\n\
497 variables in @code{readonly_data_section}.\n\
499 See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}.",
500 section *, (tree exp, int reloc, unsigned HOST_WIDE_INT align),
501 default_select_section)
503 /* Return a section for X. MODE is X's mode and ALIGN is its
504 alignment in bits. */
505 DEFHOOK
506 (select_rtx_section,
507 "Return the section into which a constant @var{x}, of mode @var{mode},\n\
508 should be placed. You can assume that @var{x} is some kind of\n\
509 constant in RTL@. The argument @var{mode} is redundant except in the\n\
510 case of a @code{const_int} rtx. @var{align} is the constant alignment\n\
511 in bits.\n\
513 The default version of this function takes care of putting symbolic\n\
514 constants in @code{flag_pic} mode in @code{data_section} and everything\n\
515 else in @code{readonly_data_section}.",
516 section *, (machine_mode mode, rtx x, unsigned HOST_WIDE_INT align),
517 default_select_rtx_section)
519 /* Select a unique section name for DECL. RELOC is the same as
520 for SELECT_SECTION. */
521 DEFHOOK
522 (unique_section,
523 "Build up a unique section name, expressed as a @code{STRING_CST} node,\n\
524 and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.\n\
525 As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether\n\
526 the initial value of @var{exp} requires link-time relocations.\n\
528 The default version of this function appends the symbol name to the\n\
529 ELF section name that would normally be used for the symbol. For\n\
530 example, the function @code{foo} would be placed in @code{.text.foo}.\n\
531 Whatever the actual target object format, this is often good enough.",
532 void, (tree decl, int reloc),
533 default_unique_section)
535 /* Return the readonly data section associated with function DECL. */
536 DEFHOOK
537 (function_rodata_section,
538 "Return the readonly data section associated with\n\
539 @samp{DECL_SECTION_NAME (@var{decl})}.\n\
540 The default version of this function selects @code{.gnu.linkonce.r.name} if\n\
541 the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name}\n\
542 if function is in @code{.text.name}, and the normal readonly-data section\n\
543 otherwise.",
544 section *, (tree decl),
545 default_function_rodata_section)
547 /* Nonnull if the target wants to override the default ".rodata" prefix
548 for mergeable data sections. */
549 DEFHOOKPOD
550 (mergeable_rodata_prefix,
551 "Usually, the compiler uses the prefix @code{\".rodata\"} to construct\n\
552 section names for mergeable constant data. Define this macro to override\n\
553 the string if a different section name should be used.",
554 const char *, ".rodata")
556 /* Return the section to be used for transactional memory clone tables. */
557 DEFHOOK
558 (tm_clone_table_section,
559 "Return the section that should be used for transactional memory clone\
560 tables.",
561 section *, (void), default_clone_table_section)
563 /* Output a constructor for a symbol with a given priority. */
564 DEFHOOK
565 (constructor,
566 "If defined, a function that outputs assembler code to arrange to call\n\
567 the function referenced by @var{symbol} at initialization time.\n\
569 Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking\n\
570 no arguments and with no return value. If the target supports initialization\n\
571 priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY};\n\
572 otherwise it must be @code{DEFAULT_INIT_PRIORITY}.\n\
574 If this macro is not defined by the target, a suitable default will\n\
575 be chosen if (1) the target supports arbitrary section names, (2) the\n\
576 target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2}\n\
577 is not defined.",
578 void, (rtx symbol, int priority), NULL)
580 /* Output a destructor for a symbol with a given priority. */
581 DEFHOOK
582 (destructor,
583 "This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination\n\
584 functions rather than initialization functions.",
585 void, (rtx symbol, int priority), NULL)
587 /* Output the assembler code for a thunk function. THUNK_DECL is the
588 declaration for the thunk function itself, FUNCTION is the decl for
589 the target function. DELTA is an immediate constant offset to be
590 added to THIS. If VCALL_OFFSET is nonzero, the word at
591 *(*this + vcall_offset) should be added to THIS. */
592 DEFHOOK
593 (output_mi_thunk,
594 "A function that outputs the assembler code for a thunk\n\
595 function, used to implement C++ virtual function calls with multiple\n\
596 inheritance. The thunk acts as a wrapper around a virtual function,\n\
597 adjusting the implicit object parameter before handing control off to\n\
598 the real function.\n\
600 First, emit code to add the integer @var{delta} to the location that\n\
601 contains the incoming first argument. Assume that this argument\n\
602 contains a pointer, and is the one used to pass the @code{this} pointer\n\
603 in C++. This is the incoming argument @emph{before} the function prologue,\n\
604 e.g.@: @samp{%o0} on a sparc. The addition must preserve the values of\n\
605 all other incoming arguments.\n\
607 Then, if @var{vcall_offset} is nonzero, an additional adjustment should be\n\
608 made after adding @code{delta}. In particular, if @var{p} is the\n\
609 adjusted pointer, the following adjustment should be made:\n\
611 @smallexample\n\
612 p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]\n\
613 @end smallexample\n\
615 After the additions, emit code to jump to @var{function}, which is a\n\
616 @code{FUNCTION_DECL}. This is a direct pure jump, not a call, and does\n\
617 not touch the return address. Hence returning from @var{FUNCTION} will\n\
618 return to whoever called the current @samp{thunk}.\n\
620 The effect must be as if @var{function} had been called directly with\n\
621 the adjusted first argument. This macro is responsible for emitting all\n\
622 of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE}\n\
623 and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked.\n\
625 The @var{thunk_fndecl} is redundant. (@var{delta} and @var{function}\n\
626 have already been extracted from it.) It might possibly be useful on\n\
627 some targets, but probably not.\n\
629 If you do not define this macro, the target-independent code in the C++\n\
630 front end will generate a less efficient heavyweight thunk that calls\n\
631 @var{function} instead of jumping to it. The generic approach does\n\
632 not support varargs.",
633 void, (FILE *file, tree thunk_fndecl, HOST_WIDE_INT delta,
634 HOST_WIDE_INT vcall_offset, tree function),
635 NULL)
637 /* Determine whether output_mi_thunk would succeed. */
638 /* ??? Ideally, this hook would not exist, and success or failure
639 would be returned from output_mi_thunk directly. But there's
640 too much undo-able setup involved in invoking output_mi_thunk.
641 Could be fixed by making output_mi_thunk emit rtl instead of
642 text to the output file. */
643 DEFHOOK
644 (can_output_mi_thunk,
645 "A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able\n\
646 to output the assembler code for the thunk function specified by the\n\
647 arguments it is passed, and false otherwise. In the latter case, the\n\
648 generic approach will be used by the C++ front end, with the limitations\n\
649 previously exposed.",
650 bool, (const_tree thunk_fndecl, HOST_WIDE_INT delta,
651 HOST_WIDE_INT vcall_offset, const_tree function),
652 hook_bool_const_tree_hwi_hwi_const_tree_false)
654 /* Output any boilerplate text needed at the beginning of a
655 translation unit. */
656 DEFHOOK
657 (file_start,
658 "Output to @code{asm_out_file} any text which the assembler expects to\n\
659 find at the beginning of a file. The default behavior is controlled\n\
660 by two flags, documented below. Unless your target's assembler is\n\
661 quite unusual, if you override the default, you should call\n\
662 @code{default_file_start} at some point in your target hook. This\n\
663 lets other target files rely on these variables.",
664 void, (void),
665 default_file_start)
667 /* Output any boilerplate text needed at the end of a translation unit. */
668 DEFHOOK
669 (file_end,
670 "Output to @code{asm_out_file} any text which the assembler expects\n\
671 to find at the end of a file. The default is to output nothing.",
672 void, (void),
673 hook_void_void)
675 /* Output any boilerplate text needed at the beginning of an
676 LTO output stream. */
677 DEFHOOK
678 (lto_start,
679 "Output to @code{asm_out_file} any text which the assembler expects\n\
680 to find at the start of an LTO section. The default is to output\n\
681 nothing.",
682 void, (void),
683 hook_void_void)
685 /* Output any boilerplate text needed at the end of an
686 LTO output stream. */
687 DEFHOOK
688 (lto_end,
689 "Output to @code{asm_out_file} any text which the assembler expects\n\
690 to find at the end of an LTO section. The default is to output\n\
691 nothing.",
692 void, (void),
693 hook_void_void)
695 /* Output any boilerplace text needed at the end of a
696 translation unit before debug and unwind info is emitted. */
697 DEFHOOK
698 (code_end,
699 "Output to @code{asm_out_file} any text which is needed before emitting\n\
700 unwind info and debug info at the end of a file. Some targets emit\n\
701 here PIC setup thunks that cannot be emitted at the end of file,\n\
702 because they couldn't have unwind info then. The default is to output\n\
703 nothing.",
704 void, (void),
705 hook_void_void)
707 /* Output an assembler pseudo-op to declare a library function name
708 external. */
709 DEFHOOK
710 (external_libcall,
711 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
712 pseudo-op to declare a library function name external. The name of the\n\
713 library function is given by @var{symref}, which is a @code{symbol_ref}.",
714 void, (rtx symref),
715 default_external_libcall)
717 /* Output an assembler directive to mark decl live. This instructs
718 linker to not dead code strip this symbol. */
719 DEFHOOK
720 (mark_decl_preserved,
721 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
722 directive to annotate @var{symbol} as used. The Darwin target uses the\n\
723 .no_dead_code_strip directive.",
724 void, (const char *symbol),
725 hook_void_constcharptr)
727 /* Output a record of the command line switches that have been passed. */
728 DEFHOOK
729 (record_gcc_switches,
730 "Provides the target with the ability to record the gcc command line\n\
731 switches that have been passed to the compiler, and options that are\n\
732 enabled. The @var{type} argument specifies what is being recorded.\n\
733 It can take the following values:\n\
735 @table @gcctabopt\n\
736 @item SWITCH_TYPE_PASSED\n\
737 @var{text} is a command line switch that has been set by the user.\n\
739 @item SWITCH_TYPE_ENABLED\n\
740 @var{text} is an option which has been enabled. This might be as a\n\
741 direct result of a command line switch, or because it is enabled by\n\
742 default or because it has been enabled as a side effect of a different\n\
743 command line switch. For example, the @option{-O2} switch enables\n\
744 various different individual optimization passes.\n\
746 @item SWITCH_TYPE_DESCRIPTIVE\n\
747 @var{text} is either NULL or some descriptive text which should be\n\
748 ignored. If @var{text} is NULL then it is being used to warn the\n\
749 target hook that either recording is starting or ending. The first\n\
750 time @var{type} is SWITCH_TYPE_DESCRIPTIVE and @var{text} is NULL, the\n\
751 warning is for start up and the second time the warning is for\n\
752 wind down. This feature is to allow the target hook to make any\n\
753 necessary preparations before it starts to record switches and to\n\
754 perform any necessary tidying up after it has finished recording\n\
755 switches.\n\
757 @item SWITCH_TYPE_LINE_START\n\
758 This option can be ignored by this target hook.\n\
760 @item SWITCH_TYPE_LINE_END\n\
761 This option can be ignored by this target hook.\n\
762 @end table\n\
764 The hook's return value must be zero. Other return values may be\n\
765 supported in the future.\n\
767 By default this hook is set to NULL, but an example implementation is\n\
768 provided for ELF based targets. Called @var{elf_record_gcc_switches},\n\
769 it records the switches as ASCII text inside a new, string mergeable\n\
770 section in the assembler output file. The name of the new section is\n\
771 provided by the @code{TARGET_ASM_RECORD_GCC_SWITCHES_SECTION} target\n\
772 hook.",
773 int, (print_switch_type type, const char *text),
774 NULL)
776 /* The name of the section that the example ELF implementation of
777 record_gcc_switches will use to store the information. Target
778 specific versions of record_gcc_switches may or may not use
779 this information. */
780 DEFHOOKPOD
781 (record_gcc_switches_section,
782 "This is the name of the section that will be created by the example\n\
783 ELF implementation of the @code{TARGET_ASM_RECORD_GCC_SWITCHES} target\n\
784 hook.",
785 const char *, ".GCC.command.line")
787 /* Output the definition of a section anchor. */
788 DEFHOOK
789 (output_anchor,
790 "Write the assembly code to define section anchor @var{x}, which is a\n\
791 @code{SYMBOL_REF} for which @samp{SYMBOL_REF_ANCHOR_P (@var{x})} is true.\n\
792 The hook is called with the assembly output position set to the beginning\n\
793 of @code{SYMBOL_REF_BLOCK (@var{x})}.\n\
795 If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses\n\
796 it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}.\n\
797 If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition\n\
798 is @code{NULL}, which disables the use of section anchors altogether.",
799 void, (rtx x),
800 default_asm_output_anchor)
802 DEFHOOK
803 (output_ident,
804 "Output a string based on @var{name}, suitable for the @samp{#ident} \
805 directive, or the equivalent directive or pragma in non-C-family languages. \
806 If this hook is not defined, nothing is output for the @samp{#ident} \
807 directive.",
808 void, (const char *name),
809 hook_void_constcharptr)
811 /* Output a DTP-relative reference to a TLS symbol. */
812 DEFHOOK
813 (output_dwarf_dtprel,
814 "If defined, this target hook is a function which outputs a DTP-relative\n\
815 reference to the given TLS symbol of the specified size.",
816 void, (FILE *file, int size, rtx x),
817 NULL)
819 /* Some target machines need to postscan each insn after it is output. */
820 DEFHOOK
821 (final_postscan_insn,
822 "If defined, this target hook is a function which is executed just after the\n\
823 output of assembler code for @var{insn}, to change the mode of the assembler\n\
824 if necessary.\n\
826 Here the argument @var{opvec} is the vector containing the operands\n\
827 extracted from @var{insn}, and @var{noperands} is the number of\n\
828 elements of the vector which contain meaningful data for this insn.\n\
829 The contents of this vector are what was used to convert the insn\n\
830 template into assembler code, so you can change the assembler mode\n\
831 by checking the contents of the vector.",
832 void, (FILE *file, rtx_insn *insn, rtx *opvec, int noperands),
833 NULL)
835 /* Emit the trampoline template. This hook may be NULL. */
836 DEFHOOK
837 (trampoline_template,
838 "This hook is called by @code{assemble_trampoline_template} to output,\n\
839 on the stream @var{f}, assembler code for a block of data that contains\n\
840 the constant parts of a trampoline. This code should not include a\n\
841 label---the label is taken care of automatically.\n\
843 If you do not define this hook, it means no template is needed\n\
844 for the target. Do not define this hook on systems where the block move\n\
845 code to copy the trampoline into place would be larger than the code\n\
846 to generate it on the spot.",
847 void, (FILE *f),
848 NULL)
850 DEFHOOK
851 (output_source_filename,
852 "Output COFF information or DWARF debugging information which indicates\
853 that filename @var{name} is the current source file to the stdio\
854 stream @var{file}.\n\
856 This target hook need not be defined if the standard form of output\
857 for the file format in use is appropriate.",
858 void ,(FILE *file, const char *name),
859 default_asm_output_source_filename)
861 DEFHOOK
862 (output_addr_const_extra,
863 "A target hook to recognize @var{rtx} patterns that @code{output_addr_const}\n\
864 can't deal with, and output assembly code to @var{file} corresponding to\n\
865 the pattern @var{x}. This may be used to allow machine-dependent\n\
866 @code{UNSPEC}s to appear within constants.\n\
868 If target hook fails to recognize a pattern, it must return @code{false},\n\
869 so that a standard error message is printed. If it prints an error message\n\
870 itself, by calling, for example, @code{output_operand_lossage}, it may just\n\
871 return @code{true}.",
872 bool, (FILE *file, rtx x),
873 hook_bool_FILEptr_rtx_false)
875 /* ??? The TARGET_PRINT_OPERAND* hooks are part of the asm_out struct,
876 even though that is not reflected in the macro name to override their
877 initializers. */
878 #undef HOOK_PREFIX
879 #define HOOK_PREFIX "TARGET_"
881 /* Emit a machine-specific insn operand. */
882 /* ??? tm.texi only documents the old macro PRINT_OPERAND,
883 not this hook, and uses a different name for the argument FILE. */
884 DEFHOOK_UNDOC
885 (print_operand,
887 void, (FILE *file, rtx x, int code),
888 default_print_operand)
890 /* Emit a machine-specific memory address. */
891 /* ??? tm.texi only documents the old macro PRINT_OPERAND_ADDRESS,
892 not this hook, and uses different argument names. */
893 DEFHOOK_UNDOC
894 (print_operand_address,
896 void, (FILE *file, rtx addr),
897 default_print_operand_address)
899 /* Determine whether CODE is a valid punctuation character for the
900 `print_operand' hook. */
901 /* ??? tm.texi only documents the old macro PRINT_OPERAND_PUNCT_VALID_P,
902 not this hook. */
903 DEFHOOK_UNDOC
904 (print_operand_punct_valid_p,
906 bool ,(unsigned char code),
907 default_print_operand_punct_valid_p)
909 /* Given a symbol name, perform same mangling as assemble_name and
910 ASM_OUTPUT_LABELREF, returning result as an IDENTIFIER_NODE. */
911 DEFHOOK
912 (mangle_assembler_name,
913 "Given a symbol @var{name}, perform same mangling as @code{varasm.c}'s\
914 @code{assemble_name}, but in memory rather than to a file stream, returning\
915 result as an @code{IDENTIFIER_NODE}. Required for correct LTO symtabs. The\
916 default implementation calls the @code{TARGET_STRIP_NAME_ENCODING} hook and\
917 then prepends the @code{USER_LABEL_PREFIX}, if any.",
918 tree, (const char *name),
919 default_mangle_assembler_name)
921 HOOK_VECTOR_END (asm_out)
923 /* Functions relating to instruction scheduling. All of these
924 default to null pointers, which haifa-sched.c looks for and handles. */
925 #undef HOOK_PREFIX
926 #define HOOK_PREFIX "TARGET_SCHED_"
927 HOOK_VECTOR (TARGET_SCHED, sched)
929 /* Given the current cost, COST, of an insn, INSN, calculate and
930 return a new cost based on its relationship to DEP_INSN through
931 the dependence LINK. The default is to make no adjustment. */
932 DEFHOOK
933 (adjust_cost,
934 "This function corrects the value of @var{cost} based on the\n\
935 relationship between @var{insn} and @var{dep_insn} through the\n\
936 dependence @var{link}. It should return the new value. The default\n\
937 is to make no adjustment to @var{cost}. This can be used for example\n\
938 to specify to the scheduler using the traditional pipeline description\n\
939 that an output- or anti-dependence does not incur the same cost as a\n\
940 data-dependence. If the scheduler using the automaton based pipeline\n\
941 description, the cost of anti-dependence is zero and the cost of\n\
942 output-dependence is maximum of one and the difference of latency\n\
943 times of the first and the second insns. If these values are not\n\
944 acceptable, you could use the hook to modify them too. See also\n\
945 @pxref{Processor pipeline description}.",
946 int, (rtx_insn *insn, rtx link, rtx_insn *dep_insn, int cost), NULL)
948 /* Adjust the priority of an insn as you see fit. Returns the new priority. */
949 DEFHOOK
950 (adjust_priority,
951 "This hook adjusts the integer scheduling priority @var{priority} of\n\
952 @var{insn}. It should return the new priority. Increase the priority to\n\
953 execute @var{insn} earlier, reduce the priority to execute @var{insn}\n\
954 later. Do not define this hook if you do not need to adjust the\n\
955 scheduling priorities of insns.",
956 int, (rtx_insn *insn, int priority), NULL)
958 /* Function which returns the maximum number of insns that can be
959 scheduled in the same machine cycle. This must be constant
960 over an entire compilation. The default is 1. */
961 DEFHOOK
962 (issue_rate,
963 "This hook returns the maximum number of instructions that can ever\n\
964 issue at the same time on the target machine. The default is one.\n\
965 Although the insn scheduler can define itself the possibility of issue\n\
966 an insn on the same cycle, the value can serve as an additional\n\
967 constraint to issue insns on the same simulated processor cycle (see\n\
968 hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).\n\
969 This value must be constant over the entire compilation. If you need\n\
970 it to vary depending on what the instructions are, you must use\n\
971 @samp{TARGET_SCHED_VARIABLE_ISSUE}.",
972 int, (void), NULL)
974 /* Calculate how much this insn affects how many more insns we
975 can emit this cycle. Default is they all cost the same. */
976 DEFHOOK
977 (variable_issue,
978 "This hook is executed by the scheduler after it has scheduled an insn\n\
979 from the ready list. It should return the number of insns which can\n\
980 still be issued in the current cycle. The default is\n\
981 @samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and\n\
982 @code{USE}, which normally are not counted against the issue rate.\n\
983 You should define this hook if some insns take more machine resources\n\
984 than others, so that fewer insns can follow them in the same cycle.\n\
985 @var{file} is either a null pointer, or a stdio stream to write any\n\
986 debug output to. @var{verbose} is the verbose level provided by\n\
987 @option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that\n\
988 was scheduled.",
989 int, (FILE *file, int verbose, rtx_insn *insn, int more), NULL)
991 /* Initialize machine-dependent scheduling code. */
992 DEFHOOK
993 (init,
994 "This hook is executed by the scheduler at the beginning of each block of\n\
995 instructions that are to be scheduled. @var{file} is either a null\n\
996 pointer, or a stdio stream to write any debug output to. @var{verbose}\n\
997 is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
998 @var{max_ready} is the maximum number of insns in the current scheduling\n\
999 region that can be live at the same time. This can be used to allocate\n\
1000 scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}.",
1001 void, (FILE *file, int verbose, int max_ready), NULL)
1003 /* Finalize machine-dependent scheduling code. */
1004 DEFHOOK
1005 (finish,
1006 "This hook is executed by the scheduler at the end of each block of\n\
1007 instructions that are to be scheduled. It can be used to perform\n\
1008 cleanup of any actions done by the other scheduling hooks. @var{file}\n\
1009 is either a null pointer, or a stdio stream to write any debug output\n\
1010 to. @var{verbose} is the verbose level provided by\n\
1011 @option{-fsched-verbose-@var{n}}.",
1012 void, (FILE *file, int verbose), NULL)
1014 /* Initialize machine-dependent function wide scheduling code. */
1015 DEFHOOK
1016 (init_global,
1017 "This hook is executed by the scheduler after function level initializations.\n\
1018 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1019 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1020 @var{old_max_uid} is the maximum insn uid when scheduling begins.",
1021 void, (FILE *file, int verbose, int old_max_uid), NULL)
1023 /* Finalize machine-dependent function wide scheduling code. */
1024 DEFHOOK
1025 (finish_global,
1026 "This is the cleanup hook corresponding to @code{TARGET_SCHED_INIT_GLOBAL}.\n\
1027 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1028 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.",
1029 void, (FILE *file, int verbose), NULL)
1031 /* Reorder insns in a machine-dependent fashion, in two different
1032 places. Default does nothing. */
1033 DEFHOOK
1034 (reorder,
1035 "This hook is executed by the scheduler after it has scheduled the ready\n\
1036 list, to allow the machine description to reorder it (for example to\n\
1037 combine two small instructions together on @samp{VLIW} machines).\n\
1038 @var{file} is either a null pointer, or a stdio stream to write any\n\
1039 debug output to. @var{verbose} is the verbose level provided by\n\
1040 @option{-fsched-verbose-@var{n}}. @var{ready} is a pointer to the ready\n\
1041 list of instructions that are ready to be scheduled. @var{n_readyp} is\n\
1042 a pointer to the number of elements in the ready list. The scheduler\n\
1043 reads the ready list in reverse order, starting with\n\
1044 @var{ready}[@var{*n_readyp} @minus{} 1] and going to @var{ready}[0]. @var{clock}\n\
1045 is the timer tick of the scheduler. You may modify the ready list and\n\
1046 the number of ready insns. The return value is the number of insns that\n\
1047 can issue this cycle; normally this is just @code{issue_rate}. See also\n\
1048 @samp{TARGET_SCHED_REORDER2}.",
1049 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1051 DEFHOOK
1052 (reorder2,
1053 "Like @samp{TARGET_SCHED_REORDER}, but called at a different time. That\n\
1054 function is called whenever the scheduler starts a new cycle. This one\n\
1055 is called once per iteration over a cycle, immediately after\n\
1056 @samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and\n\
1057 return the number of insns to be scheduled in the same cycle. Defining\n\
1058 this hook can be useful if there are frequent situations where\n\
1059 scheduling one insn causes other insns to become ready in the same\n\
1060 cycle. These other insns can then be taken into account properly.",
1061 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1063 DEFHOOK
1064 (macro_fusion_p,
1065 "This hook is used to check whether target platform supports macro fusion.",
1066 bool, (void), NULL)
1068 DEFHOOK
1069 (macro_fusion_pair_p,
1070 "This hook is used to check whether two insns could be macro fused for\n\
1071 target microarchitecture. If this hook returns true for the given insn pair\n\
1072 (@var{condgen} and @var{condjmp}), scheduler will put them into a sched\n\
1073 group, and they will not be scheduled apart.",
1074 bool, (rtx_insn *condgen, rtx_insn *condjmp), NULL)
1076 /* The following member value is a pointer to a function called
1077 after evaluation forward dependencies of insns in chain given
1078 by two parameter values (head and tail correspondingly). */
1079 DEFHOOK
1080 (dependencies_evaluation_hook,
1081 "This hook is called after evaluation forward dependencies of insns in\n\
1082 chain given by two parameter values (@var{head} and @var{tail}\n\
1083 correspondingly) but before insns scheduling of the insn chain. For\n\
1084 example, it can be used for better insn classification if it requires\n\
1085 analysis of dependencies. This hook can use backward and forward\n\
1086 dependencies of the insn scheduler because they are already\n\
1087 calculated.",
1088 void, (rtx_insn *head, rtx_insn *tail), NULL)
1090 /* The values of the following four members are pointers to functions
1091 used to simplify the automaton descriptions. dfa_pre_cycle_insn and
1092 dfa_post_cycle_insn give functions returning insns which are used to
1093 change the pipeline hazard recognizer state when the new simulated
1094 processor cycle correspondingly starts and finishes. The function
1095 defined by init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are
1096 used to initialize the corresponding insns. The default values of
1097 the members result in not changing the automaton state when the
1098 new simulated processor cycle correspondingly starts and finishes. */
1100 DEFHOOK
1101 (init_dfa_pre_cycle_insn,
1102 "The hook can be used to initialize data used by the previous hook.",
1103 void, (void), NULL)
1105 DEFHOOK
1106 (dfa_pre_cycle_insn,
1107 "The hook returns an RTL insn. The automaton state used in the\n\
1108 pipeline hazard recognizer is changed as if the insn were scheduled\n\
1109 when the new simulated processor cycle starts. Usage of the hook may\n\
1110 simplify the automaton pipeline description for some @acronym{VLIW}\n\
1111 processors. If the hook is defined, it is used only for the automaton\n\
1112 based pipeline description. The default is not to change the state\n\
1113 when the new simulated processor cycle starts.",
1114 rtx, (void), NULL)
1116 DEFHOOK
1117 (init_dfa_post_cycle_insn,
1118 "The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but\n\
1119 used to initialize data used by the previous hook.",
1120 void, (void), NULL)
1122 DEFHOOK
1123 (dfa_post_cycle_insn,
1124 "The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1125 to changed the state as if the insn were scheduled when the new\n\
1126 simulated processor cycle finishes.",
1127 rtx_insn *, (void), NULL)
1129 /* The values of the following two members are pointers to
1130 functions used to simplify the automaton descriptions.
1131 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
1132 immediately before and after cycle is advanced. */
1134 DEFHOOK
1135 (dfa_pre_advance_cycle,
1136 "The hook to notify target that the current simulated cycle is about to finish.\n\
1137 The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1138 to change the state in more complicated situations - e.g., when advancing\n\
1139 state on a single insn is not enough.",
1140 void, (void), NULL)
1142 DEFHOOK
1143 (dfa_post_advance_cycle,
1144 "The hook to notify target that new simulated cycle has just started.\n\
1145 The hook is analogous to @samp{TARGET_SCHED_DFA_POST_CYCLE_INSN} but used\n\
1146 to change the state in more complicated situations - e.g., when advancing\n\
1147 state on a single insn is not enough.",
1148 void, (void), NULL)
1150 /* The following member value is a pointer to a function returning value
1151 which defines how many insns in queue `ready' will we try for
1152 multi-pass scheduling. If the member value is nonzero and the
1153 function returns positive value, the DFA based scheduler will make
1154 multi-pass scheduling for the first cycle. In other words, we will
1155 try to choose ready insn which permits to start maximum number of
1156 insns on the same cycle. */
1157 DEFHOOK
1158 (first_cycle_multipass_dfa_lookahead,
1159 "This hook controls better choosing an insn from the ready insn queue\n\
1160 for the @acronym{DFA}-based insn scheduler. Usually the scheduler\n\
1161 chooses the first insn from the queue. If the hook returns a positive\n\
1162 value, an additional scheduler code tries all permutations of\n\
1163 @samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}\n\
1164 subsequent ready insns to choose an insn whose issue will result in\n\
1165 maximal number of issued insns on the same cycle. For the\n\
1166 @acronym{VLIW} processor, the code could actually solve the problem of\n\
1167 packing simple insns into the @acronym{VLIW} insn. Of course, if the\n\
1168 rules of @acronym{VLIW} packing are described in the automaton.\n\
1170 This code also could be used for superscalar @acronym{RISC}\n\
1171 processors. Let us consider a superscalar @acronym{RISC} processor\n\
1172 with 3 pipelines. Some insns can be executed in pipelines @var{A} or\n\
1173 @var{B}, some insns can be executed only in pipelines @var{B} or\n\
1174 @var{C}, and one insn can be executed in pipeline @var{B}. The\n\
1175 processor may issue the 1st insn into @var{A} and the 2nd one into\n\
1176 @var{B}. In this case, the 3rd insn will wait for freeing @var{B}\n\
1177 until the next cycle. If the scheduler issues the 3rd insn the first,\n\
1178 the processor could issue all 3 insns per cycle.\n\
1180 Actually this code demonstrates advantages of the automaton based\n\
1181 pipeline hazard recognizer. We try quickly and easy many insn\n\
1182 schedules to choose the best one.\n\
1184 The default is no multipass scheduling.",
1185 int, (void), NULL)
1187 /* The following member value is pointer to a function controlling
1188 what insns from the ready insn queue will be considered for the
1189 multipass insn scheduling. If the hook returns zero for insn
1190 passed as the parameter, the insn will be not chosen to be issued. */
1191 DEFHOOK
1192 (first_cycle_multipass_dfa_lookahead_guard,
1193 "\n\
1194 This hook controls what insns from the ready insn queue will be\n\
1195 considered for the multipass insn scheduling. If the hook returns\n\
1196 zero for @var{insn}, the insn will be considered in multipass scheduling.\n\
1197 Positive return values will remove @var{insn} from consideration on\n\
1198 the current round of multipass scheduling.\n\
1199 Negative return values will remove @var{insn} from consideration for given\n\
1200 number of cycles.\n\
1201 Backends should be careful about returning non-zero for highest priority\n\
1202 instruction at position 0 in the ready list. @var{ready_index} is passed\n\
1203 to allow backends make correct judgements.\n\
1205 The default is that any ready insns can be chosen to be issued.",
1206 int, (rtx_insn *insn, int ready_index), NULL)
1208 /* This hook prepares the target for a new round of multipass
1209 scheduling.
1210 DATA is a pointer to target-specific data used for multipass scheduling.
1211 READY_TRY and N_READY represent the current state of search in the
1212 optimization space. The target can filter out instructions that
1213 should not be tried during current round by setting corresponding
1214 elements in READY_TRY to non-zero.
1215 FIRST_CYCLE_INSN_P is true if this is the first round of multipass
1216 scheduling on current cycle. */
1217 DEFHOOK
1218 (first_cycle_multipass_begin,
1219 "This hook prepares the target backend for a new round of multipass\n\
1220 scheduling.",
1221 void, (void *data, signed char *ready_try, int n_ready, bool first_cycle_insn_p),
1222 NULL)
1224 /* This hook is called when multipass scheduling evaluates instruction INSN.
1225 DATA is a pointer to target-specific data that can be used to record effects
1226 of INSN on CPU that are not described in DFA.
1227 READY_TRY and N_READY represent the current state of search in the
1228 optimization space. The target can filter out instructions that
1229 should not be tried after issuing INSN by setting corresponding
1230 elements in READY_TRY to non-zero.
1231 INSN is the instruction being evaluated.
1232 PREV_DATA is a pointer to target-specific data corresponding
1233 to a state before issuing INSN. */
1234 DEFHOOK
1235 (first_cycle_multipass_issue,
1236 "This hook is called when multipass scheduling evaluates instruction INSN.",
1237 void, (void *data, signed char *ready_try, int n_ready, rtx_insn *insn,
1238 const void *prev_data), NULL)
1240 /* This hook is called when multipass scheduling backtracks from evaluation of
1241 instruction corresponding to DATA.
1242 DATA is a pointer to target-specific data that stores the effects
1243 of instruction from which the algorithm backtracks on CPU that are not
1244 described in DFA.
1245 READY_TRY and N_READY represent the current state of search in the
1246 optimization space. The target can filter out instructions that
1247 should not be tried after issuing INSN by setting corresponding
1248 elements in READY_TRY to non-zero. */
1249 DEFHOOK
1250 (first_cycle_multipass_backtrack,
1251 "This is called when multipass scheduling backtracks from evaluation of\n\
1252 an instruction.",
1253 void, (const void *data, signed char *ready_try, int n_ready), NULL)
1255 /* This hook notifies the target about the result of the concluded current
1256 round of multipass scheduling.
1257 DATA is a pointer.
1258 If DATA is non-NULL it points to target-specific data used for multipass
1259 scheduling which corresponds to instruction at the start of the chain of
1260 the winning solution. DATA is NULL when multipass scheduling cannot find
1261 a good enough solution on current cycle and decides to retry later,
1262 usually after advancing the cycle count. */
1263 DEFHOOK
1264 (first_cycle_multipass_end,
1265 "This hook notifies the target about the result of the concluded current\n\
1266 round of multipass scheduling.",
1267 void, (const void *data), NULL)
1269 /* This hook is called to initialize target-specific data for multipass
1270 scheduling after it has been allocated.
1271 DATA is a pointer to target-specific data that stores the effects
1272 of instruction from which the algorithm backtracks on CPU that are not
1273 described in DFA. */
1274 DEFHOOK
1275 (first_cycle_multipass_init,
1276 "This hook initializes target-specific data used in multipass scheduling.",
1277 void, (void *data), NULL)
1279 /* This hook is called to finalize target-specific data for multipass
1280 scheduling before it is deallocated.
1281 DATA is a pointer to target-specific data that stores the effects
1282 of instruction from which the algorithm backtracks on CPU that are not
1283 described in DFA. */
1284 DEFHOOK
1285 (first_cycle_multipass_fini,
1286 "This hook finalizes target-specific data used in multipass scheduling.",
1287 void, (void *data), NULL)
1289 /* The following member value is pointer to a function called by
1290 the insn scheduler before issuing insn passed as the third
1291 parameter on given cycle. If the hook returns nonzero, the
1292 insn is not issued on given processors cycle. Instead of that,
1293 the processor cycle is advanced. If the value passed through
1294 the last parameter is zero, the insn ready queue is not sorted
1295 on the new cycle start as usually. The first parameter passes
1296 file for debugging output. The second one passes the scheduler
1297 verbose level of the debugging output. The forth and the fifth
1298 parameter values are correspondingly processor cycle on which
1299 the previous insn has been issued and the current processor cycle. */
1300 DEFHOOK
1301 (dfa_new_cycle,
1302 "This hook is called by the insn scheduler before issuing @var{insn}\n\
1303 on cycle @var{clock}. If the hook returns nonzero,\n\
1304 @var{insn} is not issued on this processor cycle. Instead,\n\
1305 the processor cycle is advanced. If *@var{sort_p}\n\
1306 is zero, the insn ready queue is not sorted on the new cycle\n\
1307 start as usually. @var{dump} and @var{verbose} specify the file and\n\
1308 verbosity level to use for debugging output.\n\
1309 @var{last_clock} and @var{clock} are, respectively, the\n\
1310 processor cycle on which the previous insn has been issued,\n\
1311 and the current processor cycle.",
1312 int, (FILE *dump, int verbose, rtx_insn *insn, int last_clock,
1313 int clock, int *sort_p),
1314 NULL)
1316 /* The following member value is a pointer to a function called by the
1317 insn scheduler. It should return true if there exists a dependence
1318 which is considered costly by the target, between the insn
1319 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
1320 the dep that represents the dependence between the two insns. The
1321 second argument is the cost of the dependence as estimated by
1322 the scheduler. The last argument is the distance in cycles
1323 between the already scheduled insn (first parameter) and the
1324 second insn (second parameter). */
1325 DEFHOOK
1326 (is_costly_dependence,
1327 "This hook is used to define which dependences are considered costly by\n\
1328 the target, so costly that it is not advisable to schedule the insns that\n\
1329 are involved in the dependence too close to one another. The parameters\n\
1330 to this hook are as follows: The first parameter @var{_dep} is the dependence\n\
1331 being evaluated. The second parameter @var{cost} is the cost of the\n\
1332 dependence as estimated by the scheduler, and the third\n\
1333 parameter @var{distance} is the distance in cycles between the two insns.\n\
1334 The hook returns @code{true} if considering the distance between the two\n\
1335 insns the dependence between them is considered costly by the target,\n\
1336 and @code{false} otherwise.\n\
1338 Defining this hook can be useful in multiple-issue out-of-order machines,\n\
1339 where (a) it's practically hopeless to predict the actual data/resource\n\
1340 delays, however: (b) there's a better chance to predict the actual grouping\n\
1341 that will be formed, and (c) correctly emulating the grouping can be very\n\
1342 important. In such targets one may want to allow issuing dependent insns\n\
1343 closer to one another---i.e., closer than the dependence distance; however,\n\
1344 not in cases of ``costly dependences'', which this hooks allows to define.",
1345 bool, (struct _dep *_dep, int cost, int distance), NULL)
1347 DEFHOOK_UNDOC
1348 (adjust_cost_2,
1349 "Given the current cost, @var{cost}, of an insn, @var{insn}, calculate and\
1350 return a new cost based on its relationship to @var{dep_insn} through the\
1351 dependence of weakness @var{dw}. The default is to make no adjustment.",
1352 int, (rtx_insn *insn, int dep_type1, rtx_insn *dep_insn, int cost,
1353 unsigned int dw),
1354 NULL)
1356 /* The following member value is a pointer to a function called
1357 by the insn scheduler. This hook is called to notify the backend
1358 that new instructions were emitted. */
1359 DEFHOOK
1360 (h_i_d_extended,
1361 "This hook is called by the insn scheduler after emitting a new instruction to\n\
1362 the instruction stream. The hook notifies a target backend to extend its\n\
1363 per instruction data structures.",
1364 void, (void), NULL)
1366 /* Next 5 functions are for multi-point scheduling. */
1368 /* Allocate memory for scheduler context. */
1369 DEFHOOK
1370 (alloc_sched_context,
1371 "Return a pointer to a store large enough to hold target scheduling context.",
1372 void *, (void), NULL)
1374 /* Fills the context from the local machine scheduler context. */
1375 DEFHOOK
1376 (init_sched_context,
1377 "Initialize store pointed to by @var{tc} to hold target scheduling context.\n\
1378 It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the\n\
1379 beginning of the block. Otherwise, copy the current context into @var{tc}.",
1380 void, (void *tc, bool clean_p), NULL)
1382 /* Sets local machine scheduler context to a saved value. */
1383 DEFHOOK
1384 (set_sched_context,
1385 "Copy target scheduling context pointed to by @var{tc} to the current context.",
1386 void, (void *tc), NULL)
1388 /* Clears a scheduler context so it becomes like after init. */
1389 DEFHOOK
1390 (clear_sched_context,
1391 "Deallocate internal data in target scheduling context pointed to by @var{tc}.",
1392 void, (void *tc), NULL)
1394 /* Frees the scheduler context. */
1395 DEFHOOK
1396 (free_sched_context,
1397 "Deallocate a store for target scheduling context pointed to by @var{tc}.",
1398 void, (void *tc), NULL)
1400 /* The following member value is a pointer to a function called
1401 by the insn scheduler.
1402 The first parameter is an instruction, the second parameter is the type
1403 of the requested speculation, and the third parameter is a pointer to the
1404 speculative pattern of the corresponding type (set if return value == 1).
1405 It should return
1406 -1, if there is no pattern, that will satisfy the requested speculation type,
1407 0, if current pattern satisfies the requested speculation type,
1408 1, if pattern of the instruction should be changed to the newly
1409 generated one. */
1410 DEFHOOK
1411 (speculate_insn,
1412 "This hook is called by the insn scheduler when @var{insn} has only\n\
1413 speculative dependencies and therefore can be scheduled speculatively.\n\
1414 The hook is used to check if the pattern of @var{insn} has a speculative\n\
1415 version and, in case of successful check, to generate that speculative\n\
1416 pattern. The hook should return 1, if the instruction has a speculative form,\n\
1417 or @minus{}1, if it doesn't. @var{request} describes the type of requested\n\
1418 speculation. If the return value equals 1 then @var{new_pat} is assigned\n\
1419 the generated speculative pattern.",
1420 int, (rtx_insn *insn, unsigned int dep_status, rtx *new_pat), NULL)
1422 /* The following member value is a pointer to a function called
1423 by the insn scheduler. It should return true if the check instruction
1424 passed as the parameter needs a recovery block. */
1425 DEFHOOK
1426 (needs_block_p,
1427 "This hook is called by the insn scheduler during generation of recovery code\n\
1428 for @var{insn}. It should return @code{true}, if the corresponding check\n\
1429 instruction should branch to recovery code, or @code{false} otherwise.",
1430 bool, (unsigned int dep_status), NULL)
1432 /* The following member value is a pointer to a function called
1433 by the insn scheduler. It should return a pattern for the check
1434 instruction.
1435 The first parameter is a speculative instruction, the second parameter
1436 is the label of the corresponding recovery block (or null, if it is a
1437 simple check). The third parameter is the kind of speculation that
1438 is being performed. */
1439 DEFHOOK
1440 (gen_spec_check,
1441 "This hook is called by the insn scheduler to generate a pattern for recovery\n\
1442 check instruction. If @var{mutate_p} is zero, then @var{insn} is a\n\
1443 speculative instruction for which the check should be generated.\n\
1444 @var{label} is either a label of a basic block, where recovery code should\n\
1445 be emitted, or a null pointer, when requested check doesn't branch to\n\
1446 recovery code (a simple check). If @var{mutate_p} is nonzero, then\n\
1447 a pattern for a branchy check corresponding to a simple check denoted by\n\
1448 @var{insn} should be generated. In this case @var{label} can't be null.",
1449 rtx, (rtx_insn *insn, rtx_insn *label, unsigned int ds), NULL)
1451 /* The following member value is a pointer to a function that provides
1452 information about the speculation capabilities of the target.
1453 The parameter is a pointer to spec_info variable. */
1454 DEFHOOK
1455 (set_sched_flags,
1456 "This hook is used by the insn scheduler to find out what features should be\n\
1457 enabled/used.\n\
1458 The structure *@var{spec_info} should be filled in by the target.\n\
1459 The structure describes speculation types that can be used in the scheduler.",
1460 void, (struct spec_info_def *spec_info), NULL)
1462 DEFHOOK_UNDOC
1463 (get_insn_spec_ds,
1464 "Return speculation types of instruction @var{insn}.",
1465 unsigned int, (rtx_insn *insn), NULL)
1467 DEFHOOK_UNDOC
1468 (get_insn_checked_ds,
1469 "Return speculation types that are checked for instruction @var{insn}",
1470 unsigned int, (rtx_insn *insn), NULL)
1472 DEFHOOK_UNDOC
1473 (skip_rtx_p,
1474 "Return bool if rtx scanning should just skip current layer and\
1475 advance to the inner rtxes.",
1476 bool, (const_rtx x), NULL)
1478 /* The following member value is a pointer to a function that provides
1479 information about the target resource-based lower bound which is
1480 used by the swing modulo scheduler. The parameter is a pointer
1481 to ddg variable. */
1482 DEFHOOK
1483 (sms_res_mii,
1484 "This hook is called by the swing modulo scheduler to calculate a\n\
1485 resource-based lower bound which is based on the resources available in\n\
1486 the machine and the resources required by each instruction. The target\n\
1487 backend can use @var{g} to calculate such bound. A very simple lower\n\
1488 bound will be used in case this hook is not implemented: the total number\n\
1489 of instructions divided by the issue rate.",
1490 int, (struct ddg *g), NULL)
1492 /* The following member value is a function that initializes dispatch
1493 schedling and adds instructions to dispatch window according to its
1494 parameters. */
1495 DEFHOOK
1496 (dispatch_do,
1497 "This hook is called by Haifa Scheduler. It performs the operation specified\n\
1498 in its second parameter.",
1499 void, (rtx_insn *insn, int x),
1500 hook_void_rtx_insn_int)
1502 /* The following member value is a a function that returns true is
1503 dispatch schedling is supported in hardware and condition passed
1504 as the second parameter is true. */
1505 DEFHOOK
1506 (dispatch,
1507 "This hook is called by Haifa Scheduler. It returns true if dispatch scheduling\n\
1508 is supported in hardware and the condition specified in the parameter is true.",
1509 bool, (rtx_insn *insn, int x),
1510 hook_bool_rtx_insn_int_false)
1512 DEFHOOKPOD
1513 (exposed_pipeline,
1514 "True if the processor has an exposed pipeline, which means that not just\n\
1515 the order of instructions is important for correctness when scheduling, but\n\
1516 also the latencies of operations.",
1517 bool, false)
1519 /* The following member value is a function that returns number
1520 of operations reassociator should try to put in parallel for
1521 statements of the given type. By default 1 is used. */
1522 DEFHOOK
1523 (reassociation_width,
1524 "This hook is called by tree reassociator to determine a level of\n\
1525 parallelism required in output calculations chain.",
1526 int, (unsigned int opc, machine_mode mode),
1527 hook_int_uint_mode_1)
1529 /* The following member value is a function that returns priority for
1530 fusion of each instruction via pointer parameters. */
1531 DEFHOOK
1532 (fusion_priority,
1533 "This hook is called by scheduling fusion pass. It calculates fusion\n\
1534 priorities for each instruction passed in by parameter. The priorities\n\
1535 are returned via pointer parameters.\n\
1537 @var{insn} is the instruction whose priorities need to be calculated.\n\
1538 @var{max_pri} is the maximum priority can be returned in any cases.\n\
1539 @var{fusion_pri} is the pointer parameter through which @var{insn}'s\n\
1540 fusion priority should be calculated and returned.\n\
1541 @var{pri} is the pointer parameter through which @var{insn}'s priority\n\
1542 should be calculated and returned.\n\
1544 Same @var{fusion_pri} should be returned for instructions which should\n\
1545 be scheduled together. Different @var{pri} should be returned for\n\
1546 instructions with same @var{fusion_pri}. @var{fusion_pri} is the major\n\
1547 sort key, @var{pri} is the minor sort key. All instructions will be\n\
1548 scheduled according to the two priorities. All priorities calculated\n\
1549 should be between 0 (exclusive) and @var{max_pri} (inclusive). To avoid\n\
1550 false dependencies, @var{fusion_pri} of instructions which need to be\n\
1551 scheduled together should be smaller than @var{fusion_pri} of irrelevant\n\
1552 instructions.\n\
1554 Given below example:\n\
1556 ldr r10, [r1, 4]\n\
1557 add r4, r4, r10\n\
1558 ldr r15, [r2, 8]\n\
1559 sub r5, r5, r15\n\
1560 ldr r11, [r1, 0]\n\
1561 add r4, r4, r11\n\
1562 ldr r16, [r2, 12]\n\
1563 sub r5, r5, r16\n\
1565 On targets like ARM/AArch64, the two pairs of consecutive loads should be\n\
1566 merged. Since peephole2 pass can't help in this case unless consecutive\n\
1567 loads are actually next to each other in instruction flow. That's where\n\
1568 this scheduling fusion pass works. This hook calculates priority for each\n\
1569 instruction based on its fustion type, like:\n\
1571 ldr r10, [r1, 4] ; fusion_pri=99, pri=96 \n\
1572 add r4, r4, r10 ; fusion_pri=100, pri=100 \n\
1573 ldr r15, [r2, 8] ; fusion_pri=98, pri=92 \n\
1574 sub r5, r5, r15 ; fusion_pri=100, pri=100 \n\
1575 ldr r11, [r1, 0] ; fusion_pri=99, pri=100 \n\
1576 add r4, r4, r11 ; fusion_pri=100, pri=100 \n\
1577 ldr r16, [r2, 12] ; fusion_pri=98, pri=88 \n\
1578 sub r5, r5, r16 ; fusion_pri=100, pri=100 \n\
1580 Scheduling fusion pass then sorts all ready to issue instructions according\n\
1581 to the priorities. As a result, instructions of same fusion type will be\n\
1582 pushed together in instruction flow, like:\n\
1584 ldr r11, [r1, 0]\n\
1585 ldr r10, [r1, 4]\n\
1586 ldr r15, [r2, 8]\n\
1587 ldr r16, [r2, 12]\n\
1588 add r4, r4, r10\n\
1589 sub r5, r5, r15\n\
1590 add r4, r4, r11\n\
1591 sub r5, r5, r16\n\
1593 Now peephole2 pass can simply merge the two pairs of loads.\n\
1595 Since scheduling fusion pass relies on peephole2 to do real fusion\n\
1596 work, it is only enabled by default when peephole2 is in effect.\n\
1598 This is firstly introduced on ARM/AArch64 targets, please refer to\n\
1599 the hook implementation for how different fusion types are supported.",
1600 void, (rtx_insn *insn, int max_pri, int *fusion_pri, int *pri), NULL)
1602 HOOK_VECTOR_END (sched)
1604 /* Functions relating to OpenMP and Cilk Plus SIMD clones. */
1605 #undef HOOK_PREFIX
1606 #define HOOK_PREFIX "TARGET_SIMD_CLONE_"
1607 HOOK_VECTOR (TARGET_SIMD_CLONE, simd_clone)
1609 DEFHOOK
1610 (compute_vecsize_and_simdlen,
1611 "This hook should set @var{vecsize_mangle}, @var{vecsize_int}, @var{vecsize_float}\n\
1612 fields in @var{simd_clone} structure pointed by @var{clone_info} argument and also\n\
1613 @var{simdlen} field if it was previously 0.\n\
1614 The hook should return 0 if SIMD clones shouldn't be emitted,\n\
1615 or number of @var{vecsize_mangle} variants that should be emitted.",
1616 int, (struct cgraph_node *, struct cgraph_simd_clone *, tree, int), NULL)
1618 DEFHOOK
1619 (adjust,
1620 "This hook should add implicit @code{attribute(target(\"...\"))} attribute\n\
1621 to SIMD clone @var{node} if needed.",
1622 void, (struct cgraph_node *), NULL)
1624 DEFHOOK
1625 (usable,
1626 "This hook should return -1 if SIMD clone @var{node} shouldn't be used\n\
1627 in vectorized loops in current function, or non-negative number if it is\n\
1628 usable. In that case, the smaller the number is, the more desirable it is\n\
1629 to use it.",
1630 int, (struct cgraph_node *), NULL)
1632 HOOK_VECTOR_END (simd_clone)
1634 /* Functions relating to vectorization. */
1635 #undef HOOK_PREFIX
1636 #define HOOK_PREFIX "TARGET_VECTORIZE_"
1637 HOOK_VECTOR (TARGET_VECTORIZE, vectorize)
1639 /* The following member value is a pointer to a function called
1640 by the vectorizer, and return the decl of the target builtin
1641 function. */
1642 DEFHOOK
1643 (builtin_mask_for_load,
1644 "This hook should return the DECL of a function @var{f} that given an\n\
1645 address @var{addr} as an argument returns a mask @var{m} that can be\n\
1646 used to extract from two vectors the relevant data that resides in\n\
1647 @var{addr} in case @var{addr} is not properly aligned.\n\
1649 The autovectorizer, when vectorizing a load operation from an address\n\
1650 @var{addr} that may be unaligned, will generate two vector loads from\n\
1651 the two aligned addresses around @var{addr}. It then generates a\n\
1652 @code{REALIGN_LOAD} operation to extract the relevant data from the\n\
1653 two loaded vectors. The first two arguments to @code{REALIGN_LOAD},\n\
1654 @var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and\n\
1655 the third argument, @var{OFF}, defines how the data will be extracted\n\
1656 from these two vectors: if @var{OFF} is 0, then the returned vector is\n\
1657 @var{v2}; otherwise, the returned vector is composed from the last\n\
1658 @var{VS}-@var{OFF} elements of @var{v1} concatenated to the first\n\
1659 @var{OFF} elements of @var{v2}.\n\
1661 If this hook is defined, the autovectorizer will generate a call\n\
1662 to @var{f} (using the DECL tree that this hook returns) and will\n\
1663 use the return value of @var{f} as the argument @var{OFF} to\n\
1664 @code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}\n\
1665 should comply with the semantics expected by @code{REALIGN_LOAD}\n\
1666 described above.\n\
1667 If this hook is not defined, then @var{addr} will be used as\n\
1668 the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low\n\
1669 log2(@var{VS}) @minus{} 1 bits of @var{addr} will be considered.",
1670 tree, (void), NULL)
1672 /* Returns a code for builtin that realizes vectorized version of
1673 function, or NULL_TREE if not available. */
1674 DEFHOOK
1675 (builtin_vectorized_function,
1676 "This hook should return the decl of a function that implements the\n\
1677 vectorized variant of the builtin function with builtin function code\n\
1678 @var{code} or @code{NULL_TREE} if such a function is not available.\n\
1679 The value of @var{fndecl} is the builtin function declaration. The\n\
1680 return type of the vectorized function shall be of vector type\n\
1681 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1682 tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
1683 default_builtin_vectorized_function)
1685 /* Returns a function declaration for a builtin that realizes the
1686 vector conversion, or NULL_TREE if not available. */
1687 DEFHOOK
1688 (builtin_conversion,
1689 "This hook should return the DECL of a function that implements conversion of the\n\
1690 input vector of type @var{src_type} to type @var{dest_type}.\n\
1691 The value of @var{code} is one of the enumerators in @code{enum tree_code} and\n\
1692 specifies how the conversion is to be applied\n\
1693 (truncation, rounding, etc.).\n\
1695 If this hook is defined, the autovectorizer will use the\n\
1696 @code{TARGET_VECTORIZE_BUILTIN_CONVERSION} target hook when vectorizing\n\
1697 conversion. Otherwise, it will return @code{NULL_TREE}.",
1698 tree, (unsigned code, tree dest_type, tree src_type),
1699 default_builtin_vectorized_conversion)
1701 /* Cost of different vector/scalar statements in vectorization cost
1702 model. In case of misaligned vector loads and stores the cost depends
1703 on the data type and misalignment value. */
1704 DEFHOOK
1705 (builtin_vectorization_cost,
1706 "Returns cost of different scalar or vector statements for vectorization cost model.\n\
1707 For vector memory operations the cost may depend on type (@var{vectype}) and\n\
1708 misalignment value (@var{misalign}).",
1709 int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
1710 default_builtin_vectorization_cost)
1712 /* Return true if vector alignment is reachable (by peeling N
1713 iterations) for the given type. */
1714 DEFHOOK
1715 (vector_alignment_reachable,
1716 "Return true if vector alignment is reachable (by peeling N iterations) for the given type.",
1717 bool, (const_tree type, bool is_packed),
1718 default_builtin_vector_alignment_reachable)
1720 /* Return true if a vector created for vec_perm_const is valid.
1721 A NULL indicates that all constants are valid permutations. */
1722 DEFHOOK
1723 (vec_perm_const_ok,
1724 "Return true if a vector created for @code{vec_perm_const} is valid.",
1725 bool, (machine_mode, const unsigned char *sel),
1726 NULL)
1728 /* Return true if the target supports misaligned store/load of a
1729 specific factor denoted in the third parameter. The last parameter
1730 is true if the access is defined in a packed struct. */
1731 DEFHOOK
1732 (support_vector_misalignment,
1733 "This hook should return true if the target supports misaligned vector\n\
1734 store/load of a specific factor denoted in the @var{misalignment}\n\
1735 parameter. The vector store/load should be of machine mode @var{mode} and\n\
1736 the elements in the vectors should be of type @var{type}. @var{is_packed}\n\
1737 parameter is true if the memory access is defined in a packed struct.",
1738 bool,
1739 (machine_mode mode, const_tree type, int misalignment, bool is_packed),
1740 default_builtin_support_vector_misalignment)
1742 /* Return the builtin decl needed to load a vector of TYPE. */
1743 DEFHOOK
1744 (builtin_tm_load,
1745 "This hook should return the built-in decl needed to load a vector of the "
1746 "given type within a transaction.",
1747 tree,
1748 (tree),
1749 default_builtin_tm_load_store)
1751 /* Return the builtin decl needed to store a vector of TYPE. */
1752 DEFHOOK
1753 (builtin_tm_store,
1754 "This hook should return the built-in decl needed to store a vector of the "
1755 "given type within a transaction.",
1756 tree,
1757 (tree),
1758 default_builtin_tm_load_store)
1760 /* Returns the preferred mode for SIMD operations for the specified
1761 scalar mode. */
1762 DEFHOOK
1763 (preferred_simd_mode,
1764 "This hook should return the preferred mode for vectorizing scalar\n\
1765 mode @var{mode}. The default is\n\
1766 equal to @code{word_mode}, because the vectorizer can do some\n\
1767 transformations even in absence of specialized @acronym{SIMD} hardware.",
1768 machine_mode,
1769 (machine_mode mode),
1770 default_preferred_simd_mode)
1772 /* Returns a mask of vector sizes to iterate over when auto-vectorizing
1773 after processing the preferred one derived from preferred_simd_mode. */
1774 DEFHOOK
1775 (autovectorize_vector_sizes,
1776 "This hook should return a mask of sizes that should be iterated over\n\
1777 after trying to autovectorize using the vector size derived from the\n\
1778 mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}.\n\
1779 The default is zero which means to not iterate over other vector sizes.",
1780 unsigned int,
1781 (void),
1782 default_autovectorize_vector_sizes)
1784 /* Target builtin that implements vector gather operation. */
1785 DEFHOOK
1786 (builtin_gather,
1787 "Target builtin that implements vector gather operation. @var{mem_vectype}\n\
1788 is the vector type of the load and @var{index_type} is scalar type of\n\
1789 the index, scaled by @var{scale}.\n\
1790 The default is @code{NULL_TREE} which means to not vectorize gather\n\
1791 loads.",
1792 tree,
1793 (const_tree mem_vectype, const_tree index_type, int scale),
1794 NULL)
1796 /* Target function to initialize the cost model for a loop or block. */
1797 DEFHOOK
1798 (init_cost,
1799 "This hook should initialize target-specific data structures in preparation "
1800 "for modeling the costs of vectorizing a loop or basic block. The default "
1801 "allocates three unsigned integers for accumulating costs for the prologue, "
1802 "body, and epilogue of the loop or basic block. If @var{loop_info} is "
1803 "non-NULL, it identifies the loop being vectorized; otherwise a single block "
1804 "is being vectorized.",
1805 void *,
1806 (struct loop *loop_info),
1807 default_init_cost)
1809 /* Target function to record N statements of the given kind using the
1810 given vector type within the cost model data for the current loop or
1811 block. */
1812 DEFHOOK
1813 (add_stmt_cost,
1814 "This hook should update the target-specific @var{data} in response to "
1815 "adding @var{count} copies of the given @var{kind} of statement to a "
1816 "loop or basic block. The default adds the builtin vectorizer cost for "
1817 "the copies of the statement to the accumulator specified by @var{where}, "
1818 "(the prologue, body, or epilogue) and returns the amount added. The "
1819 "return value should be viewed as a tentative cost that may later be "
1820 "revised.",
1821 unsigned,
1822 (void *data, int count, enum vect_cost_for_stmt kind,
1823 struct _stmt_vec_info *stmt_info, int misalign,
1824 enum vect_cost_model_location where),
1825 default_add_stmt_cost)
1827 /* Target function to calculate the total cost of the current vectorized
1828 loop or block. */
1829 DEFHOOK
1830 (finish_cost,
1831 "This hook should complete calculations of the cost of vectorizing a loop "
1832 "or basic block based on @var{data}, and return the prologue, body, and "
1833 "epilogue costs as unsigned integers. The default returns the value of "
1834 "the three accumulators.",
1835 void,
1836 (void *data, unsigned *prologue_cost, unsigned *body_cost,
1837 unsigned *epilogue_cost),
1838 default_finish_cost)
1840 /* Function to delete target-specific cost modeling data. */
1841 DEFHOOK
1842 (destroy_cost_data,
1843 "This hook should release @var{data} and any related data structures "
1844 "allocated by TARGET_VECTORIZE_INIT_COST. The default releases the "
1845 "accumulator.",
1846 void,
1847 (void *data),
1848 default_destroy_cost_data)
1850 HOOK_VECTOR_END (vectorize)
1852 #undef HOOK_PREFIX
1853 #define HOOK_PREFIX "TARGET_"
1855 DEFHOOK
1856 (record_offload_symbol,
1857 "Used when offloaded functions are seen in the compilation unit and no named\n\
1858 sections are available. It is called once for each symbol that must be\n\
1859 recorded in the offload function and variable table.",
1860 void, (tree),
1861 hook_void_tree)
1863 /* Allow target specific overriding of option settings after options have
1864 been changed by an attribute or pragma or when it is reset at the
1865 end of the code affected by an attribute or pragma. */
1866 DEFHOOK
1867 (override_options_after_change,
1868 "This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}\n\
1869 but is called when the optimize level is changed via an attribute or\n\
1870 pragma or when it is reset at the end of the code affected by the\n\
1871 attribute or pragma. It is not called at the beginning of compilation\n\
1872 when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these\n\
1873 actions then, you should have @code{TARGET_OPTION_OVERRIDE} call\n\
1874 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.",
1875 void, (void),
1876 hook_void_void)
1878 DEFHOOK
1879 (offload_options,
1880 "Used when writing out the list of options into an LTO file. It should\n\
1881 translate any relevant target-specific options (such as the ABI in use)\n\
1882 into one of the @option{-foffload} options that exist as a common interface\n\
1883 to express such options. It should return a string containing these options,\n\
1884 separated by spaces, which the caller will free.\n",
1885 char *, (void), hook_charptr_void_null)
1887 DEFHOOK_UNDOC
1888 (eh_return_filter_mode,
1889 "Return machine mode for filter value.",
1890 machine_mode, (void),
1891 default_eh_return_filter_mode)
1893 /* Return machine mode for libgcc expanded cmp instructions. */
1894 DEFHOOK
1895 (libgcc_cmp_return_mode,
1896 "This target hook should return the mode to be used for the return value\n\
1897 of compare instructions expanded to libgcc calls. If not defined\n\
1898 @code{word_mode} is returned which is the right choice for a majority of\n\
1899 targets.",
1900 machine_mode, (void),
1901 default_libgcc_cmp_return_mode)
1903 /* Return machine mode for libgcc expanded shift instructions. */
1904 DEFHOOK
1905 (libgcc_shift_count_mode,
1906 "This target hook should return the mode to be used for the shift count operand\n\
1907 of shift instructions expanded to libgcc calls. If not defined\n\
1908 @code{word_mode} is returned which is the right choice for a majority of\n\
1909 targets.",
1910 machine_mode, (void),
1911 default_libgcc_shift_count_mode)
1913 /* Return machine mode to be used for _Unwind_Word type. */
1914 DEFHOOK
1915 (unwind_word_mode,
1916 "Return machine mode to be used for @code{_Unwind_Word} type.\n\
1917 The default is to use @code{word_mode}.",
1918 machine_mode, (void),
1919 default_unwind_word_mode)
1921 /* Given two decls, merge their attributes and return the result. */
1922 DEFHOOK
1923 (merge_decl_attributes,
1924 "Define this target hook if the merging of decl attributes needs special\n\
1925 handling. If defined, the result is a list of the combined\n\
1926 @code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.\n\
1927 @var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of\n\
1928 when this is needed are when one attribute overrides another, or when an\n\
1929 attribute is nullified by a subsequent definition. This function may\n\
1930 call @code{merge_attributes} to handle machine-independent merging.\n\
1932 @findex TARGET_DLLIMPORT_DECL_ATTRIBUTES\n\
1933 If the only target-specific handling you require is @samp{dllimport}\n\
1934 for Microsoft Windows targets, you should define the macro\n\
1935 @code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler\n\
1936 will then define a function called\n\
1937 @code{merge_dllimport_decl_attributes} which can then be defined as\n\
1938 the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also\n\
1939 add @code{handle_dll_attribute} in the attribute table for your port\n\
1940 to perform initial processing of the @samp{dllimport} and\n\
1941 @samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and\n\
1942 @file{i386/i386.c}, for example.",
1943 tree, (tree olddecl, tree newdecl),
1944 merge_decl_attributes)
1946 /* Given two types, merge their attributes and return the result. */
1947 DEFHOOK
1948 (merge_type_attributes,
1949 "Define this target hook if the merging of type attributes needs special\n\
1950 handling. If defined, the result is a list of the combined\n\
1951 @code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed\n\
1952 that @code{comptypes} has already been called and returned 1. This\n\
1953 function may call @code{merge_attributes} to handle machine-independent\n\
1954 merging.",
1955 tree, (tree type1, tree type2),
1956 merge_type_attributes)
1958 /* Table of machine attributes and functions to handle them.
1959 Ignored if NULL. */
1960 DEFHOOKPOD
1961 (attribute_table,
1962 "If defined, this target hook points to an array of @samp{struct\n\
1963 attribute_spec} (defined in @file{tree.h}) specifying the machine\n\
1964 specific attributes for this target and some of the restrictions on the\n\
1965 entities to which these attributes are applied and the arguments they\n\
1966 take.",
1967 const struct attribute_spec *, NULL)
1969 /* Return true iff attribute NAME expects a plain identifier as its first
1970 argument. */
1971 DEFHOOK
1972 (attribute_takes_identifier_p,
1973 "If defined, this target hook is a function which returns true if the\n\
1974 machine-specific attribute named @var{name} expects an identifier\n\
1975 given as its first argument to be passed on as a plain identifier, not\n\
1976 subjected to name lookup. If this is not defined, the default is\n\
1977 false for all machine-specific attributes.",
1978 bool, (const_tree name),
1979 hook_bool_const_tree_false)
1981 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
1982 one if they are compatible and two if they are nearly compatible
1983 (which causes a warning to be generated). */
1984 DEFHOOK
1985 (comp_type_attributes,
1986 "If defined, this target hook is a function which returns zero if the attributes on\n\
1987 @var{type1} and @var{type2} are incompatible, one if they are compatible,\n\
1988 and two if they are nearly compatible (which causes a warning to be\n\
1989 generated). If this is not defined, machine-specific attributes are\n\
1990 supposed always to be compatible.",
1991 int, (const_tree type1, const_tree type2),
1992 hook_int_const_tree_const_tree_1)
1994 /* Assign default attributes to the newly defined TYPE. */
1995 DEFHOOK
1996 (set_default_type_attributes,
1997 "If defined, this target hook is a function which assigns default attributes to\n\
1998 the newly defined @var{type}.",
1999 void, (tree type),
2000 hook_void_tree)
2002 /* Insert attributes on the newly created DECL. */
2003 DEFHOOK
2004 (insert_attributes,
2005 "Define this target hook if you want to be able to add attributes to a decl\n\
2006 when it is being created. This is normally useful for back ends which\n\
2007 wish to implement a pragma by using the attributes which correspond to\n\
2008 the pragma's effect. The @var{node} argument is the decl which is being\n\
2009 created. The @var{attr_ptr} argument is a pointer to the attribute list\n\
2010 for this decl. The list itself should not be modified, since it may be\n\
2011 shared with other decls, but attributes may be chained on the head of\n\
2012 the list and @code{*@var{attr_ptr}} modified to point to the new\n\
2013 attributes, or a copy of the list may be made if further changes are\n\
2014 needed.",
2015 void, (tree node, tree *attr_ptr),
2016 hook_void_tree_treeptr)
2018 /* Return true if FNDECL (which has at least one machine attribute)
2019 can be inlined despite its machine attributes, false otherwise. */
2020 DEFHOOK
2021 (function_attribute_inlinable_p,
2022 "@cindex inlining\n\
2023 This target hook returns @code{true} if it is OK to inline @var{fndecl}\n\
2024 into the current function, despite its having target-specific\n\
2025 attributes, @code{false} otherwise. By default, if a function has a\n\
2026 target specific attribute attached to it, it will not be inlined.",
2027 bool, (const_tree fndecl),
2028 hook_bool_const_tree_false)
2030 /* Return true if bitfields in RECORD_TYPE should follow the
2031 Microsoft Visual C++ bitfield layout rules. */
2032 DEFHOOK
2033 (ms_bitfield_layout_p,
2034 "This target hook returns @code{true} if bit-fields in the given\n\
2035 @var{record_type} are to be laid out following the rules of Microsoft\n\
2036 Visual C/C++, namely: (i) a bit-field won't share the same storage\n\
2037 unit with the previous bit-field if their underlying types have\n\
2038 different sizes, and the bit-field will be aligned to the highest\n\
2039 alignment of the underlying types of itself and of the previous\n\
2040 bit-field; (ii) a zero-sized bit-field will affect the alignment of\n\
2041 the whole enclosing structure, even if it is unnamed; except that\n\
2042 (iii) a zero-sized bit-field will be disregarded unless it follows\n\
2043 another bit-field of nonzero size. If this hook returns @code{true},\n\
2044 other macros that control bit-field layout are ignored.\n\
2046 When a bit-field is inserted into a packed record, the whole size\n\
2047 of the underlying type is used by one or more same-size adjacent\n\
2048 bit-fields (that is, if its long:3, 32 bits is used in the record,\n\
2049 and any additional adjacent long bit-fields are packed into the same\n\
2050 chunk of 32 bits. However, if the size changes, a new field of that\n\
2051 size is allocated). In an unpacked record, this is the same as using\n\
2052 alignment, but not equivalent when packing.\n\
2054 If both MS bit-fields and @samp{__attribute__((packed))} are used,\n\
2055 the latter will take precedence. If @samp{__attribute__((packed))} is\n\
2056 used on a single field when MS bit-fields are in use, it will take\n\
2057 precedence for that field, but the alignment of the rest of the structure\n\
2058 may affect its placement.",
2059 bool, (const_tree record_type),
2060 hook_bool_const_tree_false)
2062 /* For now this is only an interface to WORDS_BIG_ENDIAN for
2063 target-independent code like the front ends, need performance testing
2064 before switching completely to the target hook. */
2065 DEFHOOK_UNDOC
2066 (words_big_endian,
2068 bool, (void),
2069 targhook_words_big_endian)
2071 /* Likewise for FLOAT_WORDS_BIG_ENDIAN. */
2072 DEFHOOK_UNDOC
2073 (float_words_big_endian,
2075 bool, (void),
2076 targhook_float_words_big_endian)
2078 DEFHOOK
2079 (float_exceptions_rounding_supported_p,
2080 "Returns true if the target supports IEEE 754 floating-point exceptions\
2081 and rounding modes, false otherwise. This is intended to relate to the\
2082 @code{float} and @code{double} types, but not necessarily @code{long double}.\
2083 By default, returns true if the @code{adddf3} instruction pattern is\
2084 available and false otherwise, on the assumption that hardware floating\
2085 point supports exceptions and rounding modes but software floating point\
2086 does not.",
2087 bool, (void),
2088 default_float_exceptions_rounding_supported_p)
2090 /* True if the target supports decimal floating point. */
2091 DEFHOOK
2092 (decimal_float_supported_p,
2093 "Returns true if the target supports decimal floating point.",
2094 bool, (void),
2095 default_decimal_float_supported_p)
2097 /* True if the target supports fixed-point. */
2098 DEFHOOK
2099 (fixed_point_supported_p,
2100 "Returns true if the target supports fixed-point arithmetic.",
2101 bool, (void),
2102 default_fixed_point_supported_p)
2104 /* Return true if anonymous bitfields affect structure alignment. */
2105 DEFHOOK
2106 (align_anon_bitfield,
2107 "When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine\n\
2108 whether unnamed bitfields affect the alignment of the containing\n\
2109 structure. The hook should return true if the structure should inherit\n\
2110 the alignment requirements of an unnamed bitfield's type.",
2111 bool, (void),
2112 hook_bool_void_false)
2114 /* Return true if volatile bitfields should use the narrowest type possible.
2115 Return false if they should use the container type. */
2116 DEFHOOK
2117 (narrow_volatile_bitfield,
2118 "This target hook should return @code{true} if accesses to volatile bitfields\n\
2119 should use the narrowest mode possible. It should return @code{false} if\n\
2120 these accesses should use the bitfield container type.\n\
2122 The default is @code{false}.",
2123 bool, (void),
2124 hook_bool_void_false)
2126 /* Set up target-specific built-in functions. */
2127 DEFHOOK
2128 (init_builtins,
2129 "Define this hook if you have any machine-specific built-in functions\n\
2130 that need to be defined. It should be a function that performs the\n\
2131 necessary setup.\n\
2133 Machine specific built-in functions can be useful to expand special machine\n\
2134 instructions that would otherwise not normally be generated because\n\
2135 they have no equivalent in the source language (for example, SIMD vector\n\
2136 instructions or prefetch instructions).\n\
2138 To create a built-in function, call the function\n\
2139 @code{lang_hooks.builtin_function}\n\
2140 which is defined by the language front end. You can use any type nodes set\n\
2141 up by @code{build_common_tree_nodes};\n\
2142 only language front ends that use those two functions will call\n\
2143 @samp{TARGET_INIT_BUILTINS}.",
2144 void, (void),
2145 hook_void_void)
2147 /* Initialize (if INITIALIZE_P is true) and return the target-specific
2148 built-in function decl for CODE.
2149 Return NULL if that is not possible. Return error_mark_node if CODE
2150 is outside of the range of valid target builtin function codes. */
2151 DEFHOOK
2152 (builtin_decl,
2153 "Define this hook if you have any machine-specific built-in functions\n\
2154 that need to be defined. It should be a function that returns the\n\
2155 builtin function declaration for the builtin function code @var{code}.\n\
2156 If there is no such builtin and it cannot be initialized at this time\n\
2157 if @var{initialize_p} is true the function should return @code{NULL_TREE}.\n\
2158 If @var{code} is out of range the function should return\n\
2159 @code{error_mark_node}.",
2160 tree, (unsigned code, bool initialize_p), NULL)
2162 /* Expand a target-specific builtin. */
2163 DEFHOOK
2164 (expand_builtin,
2165 "\n\
2166 Expand a call to a machine specific built-in function that was set up by\n\
2167 @samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the\n\
2168 function call; the result should go to @var{target} if that is\n\
2169 convenient, and have mode @var{mode} if that is convenient.\n\
2170 @var{subtarget} may be used as the target for computing one of\n\
2171 @var{exp}'s operands. @var{ignore} is nonzero if the value is to be\n\
2172 ignored. This function should return the result of the call to the\n\
2173 built-in function.",
2174 rtx,
2175 (tree exp, rtx target, rtx subtarget, machine_mode mode, int ignore),
2176 default_expand_builtin)
2178 DEFHOOK
2179 (builtin_chkp_function,
2180 "This hook allows target to redefine built-in functions used by\n\
2181 Pointer Bounds Checker for code instrumentation. Hook should return\n\
2182 fndecl of function implementing generic builtin whose code is\n\
2183 passed in @var{fcode}. Currently following built-in functions are\n\
2184 obtained using this hook:\n\
2185 @deftypefn {Built-in Function} __bounds_type __chkp_bndmk (const void *@var{lb}, size_t @var{size})\n\
2186 Function code - BUILT_IN_CHKP_BNDMK. This built-in function is used\n\
2187 by Pointer Bounds Checker to create bound values. @var{lb} holds low\n\
2188 bound of the resulting bounds. @var{size} holds size of created bounds.\n\
2189 @end deftypefn\n\
2191 @deftypefn {Built-in Function} void __chkp_bndstx (const void *@var{ptr}, __bounds_type @var{b}, const void **@var{loc})\n\
2192 Function code - @code{BUILT_IN_CHKP_BNDSTX}. This built-in function is used\n\
2193 by Pointer Bounds Checker to store bounds @var{b} for pointer @var{ptr}\n\
2194 when @var{ptr} is stored by address @var{loc}.\n\
2195 @end deftypefn\n\
2197 @deftypefn {Built-in Function} __bounds_type __chkp_bndldx (const void **@var{loc}, const void *@var{ptr})\n\
2198 Function code - @code{BUILT_IN_CHKP_BNDLDX}. This built-in function is used\n\
2199 by Pointer Bounds Checker to get bounds of pointer @var{ptr} loaded by\n\
2200 address @var{loc}.\n\
2201 @end deftypefn\n\
2203 @deftypefn {Built-in Function} void __chkp_bndcl (const void *@var{ptr}, __bounds_type @var{b})\n\
2204 Function code - @code{BUILT_IN_CHKP_BNDCL}. This built-in function is used\n\
2205 by Pointer Bounds Checker to perform check for pointer @var{ptr} against\n\
2206 lower bound of bounds @var{b}.\n\
2207 @end deftypefn\n\
2209 @deftypefn {Built-in Function} void __chkp_bndcu (const void *@var{ptr}, __bounds_type @var{b})\n\
2210 Function code - @code{BUILT_IN_CHKP_BNDCU}. This built-in function is used\n\
2211 by Pointer Bounds Checker to perform check for pointer @var{ptr} against\n\
2212 upper bound of bounds @var{b}.\n\
2213 @end deftypefn\n\
2215 @deftypefn {Built-in Function} __bounds_type __chkp_bndret (void *@var{ptr})\n\
2216 Function code - @code{BUILT_IN_CHKP_BNDRET}. This built-in function is used\n\
2217 by Pointer Bounds Checker to obtain bounds returned by a call statement.\n\
2218 @var{ptr} passed to built-in is @code{SSA_NAME} returned by the call.\n\
2219 @end deftypefn\n\
2221 @deftypefn {Built-in Function} __bounds_type __chkp_intersect (__bounds_type @var{b1}, __bounds_type @var{b2})\n\
2222 Function code - @code{BUILT_IN_CHKP_INTERSECT}. This built-in function\n\
2223 returns intersection of bounds @var{b1} and @var{b2}.\n\
2224 @end deftypefn\n\
2226 @deftypefn {Built-in Function} __bounds_type __chkp_narrow (const void *@var{ptr}, __bounds_type @var{b}, size_t @var{s})\n\
2227 Function code - @code{BUILT_IN_CHKP_NARROW}. This built-in function\n\
2228 returns intersection of bounds @var{b} and\n\
2229 [@var{ptr}, @var{ptr} + @var{s} - @code{1}].\n\
2230 @end deftypefn\n\
2232 @deftypefn {Built-in Function} size_t __chkp_sizeof (const void *@var{ptr})\n\
2233 Function code - @code{BUILT_IN_CHKP_SIZEOF}. This built-in function\n\
2234 returns size of object referenced by @var{ptr}. @var{ptr} is always\n\
2235 @code{ADDR_EXPR} of @code{VAR_DECL}. This built-in is used by\n\
2236 Pointer Bounds Checker when bounds of object cannot be computed statically\n\
2237 (e.g. object has incomplete type).\n\
2238 @end deftypefn\n\
2240 @deftypefn {Built-in Function} const void *__chkp_extract_lower (__bounds_type @var{b})\n\
2241 Function code - @code{BUILT_IN_CHKP_EXTRACT_LOWER}. This built-in function\n\
2242 returns lower bound of bounds @var{b}.\n\
2243 @end deftypefn\n\
2245 @deftypefn {Built-in Function} const void *__chkp_extract_upper (__bounds_type @var{b})\n\
2246 Function code - @code{BUILT_IN_CHKP_EXTRACT_UPPER}. This built-in function\n\
2247 returns upper bound of bounds @var{b}.\n\
2248 @end deftypefn",
2249 tree, (unsigned fcode),
2250 default_builtin_chkp_function)
2252 DEFHOOK
2253 (chkp_bound_type,
2254 "Return type to be used for bounds",
2255 tree, (void),
2256 default_chkp_bound_type)
2258 DEFHOOK
2259 (chkp_bound_mode,
2260 "Return mode to be used for bounds.",
2261 enum machine_mode, (void),
2262 default_chkp_bound_mode)
2264 DEFHOOK
2265 (chkp_make_bounds_constant,
2266 "Return constant used to statically initialize constant bounds\n\
2267 with specified lower bound @var{lb} and upper bounds @var{ub}.",
2268 tree, (HOST_WIDE_INT lb, HOST_WIDE_INT ub),
2269 default_chkp_make_bounds_constant)
2271 DEFHOOK
2272 (chkp_initialize_bounds,
2273 "Generate a list of statements @var{stmts} to initialize pointer\n\
2274 bounds variable @var{var} with bounds @var{lb} and @var{ub}. Return\n\
2275 the number of generated statements.",
2276 int, (tree var, tree lb, tree ub, tree *stmts),
2277 default_chkp_initialize_bounds)
2279 /* Select a replacement for a target-specific builtin. This is done
2280 *before* regular type checking, and so allows the target to
2281 implement a crude form of function overloading. The result is a
2282 complete expression that implements the operation. PARAMS really
2283 has type VEC(tree,gc)*, but we don't want to include tree.h here. */
2284 DEFHOOK
2285 (resolve_overloaded_builtin,
2286 "Select a replacement for a machine specific built-in function that\n\
2287 was set up by @samp{TARGET_INIT_BUILTINS}. This is done\n\
2288 @emph{before} regular type checking, and so allows the target to\n\
2289 implement a crude form of function overloading. @var{fndecl} is the\n\
2290 declaration of the built-in function. @var{arglist} is the list of\n\
2291 arguments passed to the built-in function. The result is a\n\
2292 complete expression that implements the operation, usually\n\
2293 another @code{CALL_EXPR}.\n\
2294 @var{arglist} really has type @samp{VEC(tree,gc)*}",
2295 tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
2297 /* Fold a target-specific builtin to a tree valid for both GIMPLE
2298 and GENERIC. */
2299 DEFHOOK
2300 (fold_builtin,
2301 "Fold a call to a machine specific built-in function that was set up by\n\
2302 @samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the\n\
2303 built-in function. @var{n_args} is the number of arguments passed to\n\
2304 the function; the arguments themselves are pointed to by @var{argp}.\n\
2305 The result is another tree, valid for both GIMPLE and GENERIC,\n\
2306 containing a simplified expression for the call's result. If\n\
2307 @var{ignore} is true the value will be ignored.",
2308 tree, (tree fndecl, int n_args, tree *argp, bool ignore),
2309 hook_tree_tree_int_treep_bool_null)
2311 /* Fold a target-specific builtin to a valid GIMPLE tree. */
2312 DEFHOOK
2313 (gimple_fold_builtin,
2314 "Fold a call to a machine specific built-in function that was set up\n\
2315 by @samp{TARGET_INIT_BUILTINS}. @var{gsi} points to the gimple\n\
2316 statement holding the function call. Returns true if any change\n\
2317 was made to the GIMPLE stream.",
2318 bool, (gimple_stmt_iterator *gsi),
2319 hook_bool_gsiptr_false)
2321 /* Target hook is used to compare the target attributes in two functions to
2322 determine which function's features get higher priority. This is used
2323 during function multi-versioning to figure out the order in which two
2324 versions must be dispatched. A function version with a higher priority
2325 is checked for dispatching earlier. DECL1 and DECL2 are
2326 the two function decls that will be compared. It returns positive value
2327 if DECL1 is higher priority, negative value if DECL2 is higher priority
2328 and 0 if they are the same. */
2329 DEFHOOK
2330 (compare_version_priority,
2331 "This hook is used to compare the target attributes in two functions to\n\
2332 determine which function's features get higher priority. This is used\n\
2333 during function multi-versioning to figure out the order in which two\n\
2334 versions must be dispatched. A function version with a higher priority\n\
2335 is checked for dispatching earlier. @var{decl1} and @var{decl2} are\n\
2336 the two function decls that will be compared.",
2337 int, (tree decl1, tree decl2), NULL)
2339 /* Target hook is used to generate the dispatcher logic to invoke the right
2340 function version at run-time for a given set of function versions.
2341 ARG points to the callgraph node of the dispatcher function whose body
2342 must be generated. */
2343 DEFHOOK
2344 (generate_version_dispatcher_body,
2345 "This hook is used to generate the dispatcher logic to invoke the right\n\
2346 function version at run-time for a given set of function versions.\n\
2347 @var{arg} points to the callgraph node of the dispatcher function whose\n\
2348 body must be generated.",
2349 tree, (void *arg), NULL)
2351 /* Target hook is used to get the dispatcher function for a set of function
2352 versions. The dispatcher function is called to invoke the right function
2353 version at run-time. DECL is one version from a set of semantically
2354 identical versions. */
2355 DEFHOOK
2356 (get_function_versions_dispatcher,
2357 "This hook is used to get the dispatcher function for a set of function\n\
2358 versions. The dispatcher function is called to invoke the right function\n\
2359 version at run-time. @var{decl} is one version from a set of semantically\n\
2360 identical versions.",
2361 tree, (void *decl), NULL)
2363 /* Returns a code for a target-specific builtin that implements
2364 reciprocal of the function, or NULL_TREE if not available. */
2365 DEFHOOK
2366 (builtin_reciprocal,
2367 "This hook should return the DECL of a function that implements reciprocal of\n\
2368 the builtin function with builtin function code @var{fn}, or\n\
2369 @code{NULL_TREE} if such a function is not available. @var{md_fn} is true\n\
2370 when @var{fn} is a code of a machine-dependent builtin function. When\n\
2371 @var{sqrt} is true, additional optimizations that apply only to the reciprocal\n\
2372 of a square root function are performed, and only reciprocals of @code{sqrt}\n\
2373 function are valid.",
2374 tree, (unsigned fn, bool md_fn, bool sqrt),
2375 default_builtin_reciprocal)
2377 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
2378 string containing the C++ mangling for TYPE. In all other cases, return
2379 NULL. */
2380 DEFHOOK
2381 (mangle_type,
2382 "If your target defines any fundamental types, or any types your target\n\
2383 uses should be mangled differently from the default, define this hook\n\
2384 to return the appropriate encoding for these types as part of a C++\n\
2385 mangled name. The @var{type} argument is the tree structure representing\n\
2386 the type to be mangled. The hook may be applied to trees which are\n\
2387 not target-specific fundamental types; it should return @code{NULL}\n\
2388 for all such types, as well as arguments it does not recognize. If the\n\
2389 return value is not @code{NULL}, it must point to a statically-allocated\n\
2390 string constant.\n\
2392 Target-specific fundamental types might be new fundamental types or\n\
2393 qualified versions of ordinary fundamental types. Encode new\n\
2394 fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}\n\
2395 is the name used for the type in source code, and @var{n} is the\n\
2396 length of @var{name} in decimal. Encode qualified versions of\n\
2397 ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where\n\
2398 @var{name} is the name used for the type qualifier in source code,\n\
2399 @var{n} is the length of @var{name} as above, and @var{code} is the\n\
2400 code used to represent the unqualified version of this type. (See\n\
2401 @code{write_builtin_type} in @file{cp/mangle.c} for the list of\n\
2402 codes.) In both cases the spaces are for clarity; do not include any\n\
2403 spaces in your string.\n\
2405 This hook is applied to types prior to typedef resolution. If the mangled\n\
2406 name for a particular type depends only on that type's main variant, you\n\
2407 can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}\n\
2408 before mangling.\n\
2410 The default version of this hook always returns @code{NULL}, which is\n\
2411 appropriate for a target that does not define any new fundamental\n\
2412 types.",
2413 const char *, (const_tree type),
2414 hook_constcharptr_const_tree_null)
2416 /* Make any adjustments to libfunc names needed for this target. */
2417 DEFHOOK
2418 (init_libfuncs,
2419 "This hook should declare additional library routines or rename\n\
2420 existing ones, using the functions @code{set_optab_libfunc} and\n\
2421 @code{init_one_libfunc} defined in @file{optabs.c}.\n\
2422 @code{init_optabs} calls this macro after initializing all the normal\n\
2423 library routines.\n\
2425 The default is to do nothing. Most ports don't need to define this hook.",
2426 void, (void),
2427 hook_void_void)
2429 /* Add a __gnu_ prefix to library functions rather than just __. */
2430 DEFHOOKPOD
2431 (libfunc_gnu_prefix,
2432 "If false (the default), internal library routines start with two\n\
2433 underscores. If set to true, these routines start with @code{__gnu_}\n\
2434 instead. E.g., @code{__muldi3} changes to @code{__gnu_muldi3}. This\n\
2435 currently only affects functions defined in @file{libgcc2.c}. If this\n\
2436 is set to true, the @file{tm.h} file must also\n\
2437 @code{#define LIBGCC2_GNU_PREFIX}.",
2438 bool, false)
2440 /* Given a decl, a section name, and whether the decl initializer
2441 has relocs, choose attributes for the section. */
2442 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
2443 DEFHOOK
2444 (section_type_flags,
2445 "Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}\n\
2446 based on a variable or function decl, a section name, and whether or not the\n\
2447 declaration's initializer may contain runtime relocations. @var{decl} may be\n\
2448 null, in which case read-write data should be assumed.\n\
2450 The default version of this function handles choosing code vs data,\n\
2451 read-only vs read-write data, and @code{flag_pic}. You should only\n\
2452 need to override this if your target has special flags that might be\n\
2453 set via @code{__attribute__}.",
2454 unsigned int, (tree decl, const char *name, int reloc),
2455 default_section_type_flags)
2457 DEFHOOK
2458 (libc_has_function,
2459 "This hook determines whether a function from a class of functions\n\
2460 @var{fn_class} is present at the runtime.",
2461 bool, (enum function_class fn_class),
2462 default_libc_has_function)
2464 /* True if new jumps cannot be created, to replace existing ones or
2465 not, at the current point in the compilation. */
2466 DEFHOOK
2467 (cannot_modify_jumps_p,
2468 "This target hook returns @code{true} past the point in which new jump\n\
2469 instructions could be created. On machines that require a register for\n\
2470 every jump such as the SHmedia ISA of SH5, this point would typically be\n\
2471 reload, so this target hook should be defined to a function such as:\n\
2473 @smallexample\n\
2474 static bool\n\
2475 cannot_modify_jumps_past_reload_p ()\n\
2476 @{\n\
2477 return (reload_completed || reload_in_progress);\n\
2478 @}\n\
2479 @end smallexample",
2480 bool, (void),
2481 hook_bool_void_false)
2483 /* True if FOLLOWER may be modified to follow FOLLOWEE. */
2484 DEFHOOK
2485 (can_follow_jump,
2486 "FOLLOWER and FOLLOWEE are JUMP_INSN instructions;\
2487 return true if FOLLOWER may be modified to follow FOLLOWEE;\
2488 false, if it can't.\
2489 For example, on some targets, certain kinds of branches can't be made to\
2490 follow through a hot/cold partitioning.",
2491 bool, (const rtx_insn *follower, const rtx_insn *followee),
2492 hook_bool_const_rtx_insn_const_rtx_insn_true)
2494 /* Return a register class for which branch target register
2495 optimizations should be applied. */
2496 DEFHOOK
2497 (branch_target_register_class,
2498 "This target hook returns a register class for which branch target register\n\
2499 optimizations should be applied. All registers in this class should be\n\
2500 usable interchangeably. After reload, registers in this class will be\n\
2501 re-allocated and loads will be hoisted out of loops and be subjected\n\
2502 to inter-block scheduling.",
2503 reg_class_t, (void),
2504 default_branch_target_register_class)
2506 /* Return true if branch target register optimizations should include
2507 callee-saved registers that are not already live during the current
2508 function. AFTER_PE_GEN is true if prologues and epilogues have
2509 already been generated. */
2510 DEFHOOK
2511 (branch_target_register_callee_saved,
2512 "Branch target register optimization will by default exclude callee-saved\n\
2513 registers\n\
2514 that are not already live during the current function; if this target hook\n\
2515 returns true, they will be included. The target code must than make sure\n\
2516 that all target registers in the class returned by\n\
2517 @samp{TARGET_BRANCH_TARGET_REGISTER_CLASS} that might need saving are\n\
2518 saved. @var{after_prologue_epilogue_gen} indicates if prologues and\n\
2519 epilogues have already been generated. Note, even if you only return\n\
2520 true when @var{after_prologue_epilogue_gen} is false, you still are likely\n\
2521 to have to make special provisions in @code{INITIAL_ELIMINATION_OFFSET}\n\
2522 to reserve space for caller-saved target registers.",
2523 bool, (bool after_prologue_epilogue_gen),
2524 hook_bool_bool_false)
2526 /* Return true if the target supports conditional execution. */
2527 DEFHOOK
2528 (have_conditional_execution,
2529 "This target hook returns true if the target supports conditional execution.\n\
2530 This target hook is required only when the target has several different\n\
2531 modes and they have different conditional execution capability, such as ARM.",
2532 bool, (void),
2533 default_have_conditional_execution)
2535 DEFHOOK
2536 (gen_ccmp_first,
2537 "This function emits a comparison insn for the first of a sequence of\n\
2538 conditional comparisions. It returns a comparison expression appropriate\n\
2539 for passing to @code{gen_ccmp_next} or @code{cbranch_optab}. @var{code} is\n\
2540 the @code{rtx_code} of the compare for @var{op0} and @var{op1}.",
2541 rtx, (int code, rtx op0, rtx op1),
2542 NULL)
2544 DEFHOOK
2545 (gen_ccmp_next,
2546 "This function emits a conditional comparison within a sequence of\n\
2547 conditional comparisons. The @var{prev} expression is the result of a\n\
2548 prior call to @code{gen_ccmp_first} or @code{gen_ccmp_next}. It may return\n\
2549 @code{NULL} if the combination of @var{prev} and this comparison is\n\
2550 not supported, otherwise the result must be appropriate for passing to\n\
2551 @code{gen_ccmp_next} or @code{cbranch_optab}. @var{code} is the\n\
2552 @code{rtx_code} of the compare for @var{op0} and @var{op1}. @var{bit_code}\n\
2553 is @code{AND} or @code{IOR}, which is the op on the two compares.",
2554 rtx, (rtx prev, int cmp_code, rtx op0, rtx op1, int bit_code),
2555 NULL)
2557 /* Return a new value for loop unroll size. */
2558 DEFHOOK
2559 (loop_unroll_adjust,
2560 "This target hook returns a new value for the number of times @var{loop}\n\
2561 should be unrolled. The parameter @var{nunroll} is the number of times\n\
2562 the loop is to be unrolled. The parameter @var{loop} is a pointer to\n\
2563 the loop, which is going to be checked for unrolling. This target hook\n\
2564 is required only when the target has special constraints like maximum\n\
2565 number of memory accesses.",
2566 unsigned, (unsigned nunroll, struct loop *loop),
2567 NULL)
2569 /* True if X is a legitimate MODE-mode immediate operand. */
2570 DEFHOOK
2571 (legitimate_constant_p,
2572 "This hook returns true if @var{x} is a legitimate constant for a\n\
2573 @var{mode}-mode immediate operand on the target machine. You can assume that\n\
2574 @var{x} satisfies @code{CONSTANT_P}, so you need not check this.\n\
2576 The default definition returns true.",
2577 bool, (machine_mode mode, rtx x),
2578 hook_bool_mode_rtx_true)
2580 /* True if the constant X cannot be placed in the constant pool. */
2581 DEFHOOK
2582 (cannot_force_const_mem,
2583 "This hook should return true if @var{x} is of a form that cannot (or\n\
2584 should not) be spilled to the constant pool. @var{mode} is the mode\n\
2585 of @var{x}.\n\
2587 The default version of this hook returns false.\n\
2589 The primary reason to define this hook is to prevent reload from\n\
2590 deciding that a non-legitimate constant would be better reloaded\n\
2591 from the constant pool instead of spilling and reloading a register\n\
2592 holding the constant. This restriction is often true of addresses\n\
2593 of TLS symbols for various targets.",
2594 bool, (machine_mode mode, rtx x),
2595 hook_bool_mode_rtx_false)
2597 DEFHOOK_UNDOC
2598 (cannot_copy_insn_p,
2599 "True if the insn @var{x} cannot be duplicated.",
2600 bool, (rtx_insn *), NULL)
2602 /* True if X is considered to be commutative. */
2603 DEFHOOK
2604 (commutative_p,
2605 "This target hook returns @code{true} if @var{x} is considered to be commutative.\n\
2606 Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider\n\
2607 PLUS to be commutative inside a MEM@. @var{outer_code} is the rtx code\n\
2608 of the enclosing rtl, if known, otherwise it is UNKNOWN.",
2609 bool, (const_rtx x, int outer_code),
2610 hook_bool_const_rtx_commutative_p)
2612 /* True if ADDR is an address-expression whose effect depends
2613 on the mode of the memory reference it is used in. */
2614 DEFHOOK
2615 (mode_dependent_address_p,
2616 "This hook returns @code{true} if memory address @var{addr} in address\n\
2617 space @var{addrspace} can have\n\
2618 different meanings depending on the machine mode of the memory\n\
2619 reference it is used for or if the address is valid for some modes\n\
2620 but not others.\n\
2622 Autoincrement and autodecrement addresses typically have mode-dependent\n\
2623 effects because the amount of the increment or decrement is the size\n\
2624 of the operand being addressed. Some machines have other mode-dependent\n\
2625 addresses. Many RISC machines have no mode-dependent addresses.\n\
2627 You may assume that @var{addr} is a valid address for the machine.\n\
2629 The default version of this hook returns @code{false}.",
2630 bool, (const_rtx addr, addr_space_t addrspace),
2631 default_mode_dependent_address_p)
2633 /* Given an invalid address X for a given machine mode, try machine-specific
2634 ways to make it legitimate. Return X or an invalid address on failure. */
2635 DEFHOOK
2636 (legitimize_address,
2637 "This hook is given an invalid memory address @var{x} for an\n\
2638 operand of mode @var{mode} and should try to return a valid memory\n\
2639 address.\n\
2641 @findex break_out_memory_refs\n\
2642 @var{x} will always be the result of a call to @code{break_out_memory_refs},\n\
2643 and @var{oldx} will be the operand that was given to that function to produce\n\
2644 @var{x}.\n\
2646 The code of the hook should not alter the substructure of\n\
2647 @var{x}. If it transforms @var{x} into a more legitimate form, it\n\
2648 should return the new @var{x}.\n\
2650 It is not necessary for this hook to come up with a legitimate address,\n\
2651 with the exception of native TLS addresses (@pxref{Emulated TLS}).\n\
2652 The compiler has standard ways of doing so in all cases. In fact, if\n\
2653 the target supports only emulated TLS, it\n\
2654 is safe to omit this hook or make it return @var{x} if it cannot find\n\
2655 a valid way to legitimize the address. But often a machine-dependent\n\
2656 strategy can generate better code.",
2657 rtx, (rtx x, rtx oldx, machine_mode mode),
2658 default_legitimize_address)
2660 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
2661 DEFHOOK
2662 (delegitimize_address,
2663 "This hook is used to undo the possibly obfuscating effects of the\n\
2664 @code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target\n\
2665 macros. Some backend implementations of these macros wrap symbol\n\
2666 references inside an @code{UNSPEC} rtx to represent PIC or similar\n\
2667 addressing modes. This target hook allows GCC's optimizers to understand\n\
2668 the semantics of these opaque @code{UNSPEC}s by converting them back\n\
2669 into their original form.",
2670 rtx, (rtx x),
2671 delegitimize_mem_from_attrs)
2673 /* Given an RTX, return true if it is not ok to emit it into debug info
2674 section. */
2675 DEFHOOK
2676 (const_not_ok_for_debug_p,
2677 "This hook should return true if @var{x} should not be emitted into\n\
2678 debug sections.",
2679 bool, (rtx x),
2680 hook_bool_rtx_false)
2682 /* Given an address RTX, say whether it is valid. */
2683 DEFHOOK
2684 (legitimate_address_p,
2685 "A function that returns whether @var{x} (an RTX) is a legitimate memory\n\
2686 address on the target machine for a memory operand of mode @var{mode}.\n\
2688 Legitimate addresses are defined in two variants: a strict variant and a\n\
2689 non-strict one. The @var{strict} parameter chooses which variant is\n\
2690 desired by the caller.\n\
2692 The strict variant is used in the reload pass. It must be defined so\n\
2693 that any pseudo-register that has not been allocated a hard register is\n\
2694 considered a memory reference. This is because in contexts where some\n\
2695 kind of register is required, a pseudo-register with no hard register\n\
2696 must be rejected. For non-hard registers, the strict variant should look\n\
2697 up the @code{reg_renumber} array; it should then proceed using the hard\n\
2698 register number in the array, or treat the pseudo as a memory reference\n\
2699 if the array holds @code{-1}.\n\
2701 The non-strict variant is used in other passes. It must be defined to\n\
2702 accept all pseudo-registers in every context where some kind of\n\
2703 register is required.\n\
2705 Normally, constant addresses which are the sum of a @code{symbol_ref}\n\
2706 and an integer are stored inside a @code{const} RTX to mark them as\n\
2707 constant. Therefore, there is no need to recognize such sums\n\
2708 specifically as legitimate addresses. Normally you would simply\n\
2709 recognize any @code{const} as legitimate.\n\
2711 Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant\n\
2712 sums that are not marked with @code{const}. It assumes that a naked\n\
2713 @code{plus} indicates indexing. If so, then you @emph{must} reject such\n\
2714 naked constant sums as illegitimate addresses, so that none of them will\n\
2715 be given to @code{PRINT_OPERAND_ADDRESS}.\n\
2717 @cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation\n\
2718 On some machines, whether a symbolic address is legitimate depends on\n\
2719 the section that the address refers to. On these machines, define the\n\
2720 target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information\n\
2721 into the @code{symbol_ref}, and then check for it here. When you see a\n\
2722 @code{const}, you will have to look inside it to find the\n\
2723 @code{symbol_ref} in order to determine the section. @xref{Assembler\n\
2724 Format}.\n\
2726 @cindex @code{GO_IF_LEGITIMATE_ADDRESS}\n\
2727 Some ports are still using a deprecated legacy substitute for\n\
2728 this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro. This macro\n\
2729 has this syntax:\n\
2731 @example\n\
2732 #define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})\n\
2733 @end example\n\
2735 @noindent\n\
2736 and should @code{goto @var{label}} if the address @var{x} is a valid\n\
2737 address on the target machine for a memory operand of mode @var{mode}.\n\
2739 @findex REG_OK_STRICT\n\
2740 Compiler source files that want to use the strict variant of this\n\
2741 macro define the macro @code{REG_OK_STRICT}. You should use an\n\
2742 @code{#ifdef REG_OK_STRICT} conditional to define the strict variant in\n\
2743 that case and the non-strict variant otherwise.\n\
2745 Using the hook is usually simpler because it limits the number of\n\
2746 files that are recompiled when changes are made.",
2747 bool, (machine_mode mode, rtx x, bool strict),
2748 default_legitimate_address_p)
2750 /* True if the given constant can be put into an object_block. */
2751 DEFHOOK
2752 (use_blocks_for_constant_p,
2753 "This hook should return true if pool entries for constant @var{x} can\n\
2754 be placed in an @code{object_block} structure. @var{mode} is the mode\n\
2755 of @var{x}.\n\
2757 The default version returns false for all constants.",
2758 bool, (machine_mode mode, const_rtx x),
2759 hook_bool_mode_const_rtx_false)
2761 /* True if the given decl can be put into an object_block. */
2762 DEFHOOK
2763 (use_blocks_for_decl_p,
2764 "This hook should return true if pool entries for @var{decl} should\n\
2765 be placed in an @code{object_block} structure.\n\
2767 The default version returns true for all decls.",
2768 bool, (const_tree decl),
2769 hook_bool_const_tree_true)
2771 /* The minimum and maximum byte offsets for anchored addresses. */
2772 DEFHOOKPOD
2773 (min_anchor_offset,
2774 "The minimum offset that should be applied to a section anchor.\n\
2775 On most targets, it should be the smallest offset that can be\n\
2776 applied to a base register while still giving a legitimate address\n\
2777 for every mode. The default value is 0.",
2778 HOST_WIDE_INT, 0)
2780 DEFHOOKPOD
2781 (max_anchor_offset,
2782 "Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)\n\
2783 offset that should be applied to section anchors. The default\n\
2784 value is 0.",
2785 HOST_WIDE_INT, 0)
2787 /* True if section anchors can be used to access the given symbol. */
2788 DEFHOOK
2789 (use_anchors_for_symbol_p,
2790 "Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}\n\
2791 @var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and\n\
2792 @samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.\n\
2794 The default version is correct for most targets, but you might need to\n\
2795 intercept this hook to handle things like target-specific attributes\n\
2796 or target-specific sections.",
2797 bool, (const_rtx x),
2798 default_use_anchors_for_symbol_p)
2800 /* True if target supports indirect functions. */
2801 DEFHOOK
2802 (has_ifunc_p,
2803 "It returns true if the target supports GNU indirect functions.\n\
2804 The support includes the assembler, linker and dynamic linker.\n\
2805 The default value of this hook is based on target's libc.",
2806 bool, (void),
2807 default_has_ifunc_p)
2809 /* True if it is OK to do sibling call optimization for the specified
2810 call expression EXP. DECL will be the called function, or NULL if
2811 this is an indirect call. */
2812 DEFHOOK
2813 (function_ok_for_sibcall,
2814 "True if it is OK to do sibling call optimization for the specified\n\
2815 call expression @var{exp}. @var{decl} will be the called function,\n\
2816 or @code{NULL} if this is an indirect call.\n\
2818 It is not uncommon for limitations of calling conventions to prevent\n\
2819 tail calls to functions outside the current unit of translation, or\n\
2820 during PIC compilation. The hook is used to enforce these restrictions,\n\
2821 as the @code{sibcall} md pattern can not fail, or fall over to a\n\
2822 ``normal'' call. The criteria for successful sibling call optimization\n\
2823 may vary greatly between different architectures.",
2824 bool, (tree decl, tree exp),
2825 hook_bool_tree_tree_false)
2827 /* Establish appropriate back-end context for processing the function
2828 FNDECL. The argument might be NULL to indicate processing at top
2829 level, outside of any function scope. */
2830 DEFHOOK
2831 (set_current_function,
2832 "The compiler invokes this hook whenever it changes its current function\n\
2833 context (@code{cfun}). You can define this function if\n\
2834 the back end needs to perform any initialization or reset actions on a\n\
2835 per-function basis. For example, it may be used to implement function\n\
2836 attributes that affect register usage or code generation patterns.\n\
2837 The argument @var{decl} is the declaration for the new function context,\n\
2838 and may be null to indicate that the compiler has left a function context\n\
2839 and is returning to processing at the top level.\n\
2840 The default hook function does nothing.\n\
2842 GCC sets @code{cfun} to a dummy function context during initialization of\n\
2843 some parts of the back end. The hook function is not invoked in this\n\
2844 situation; you need not worry about the hook being invoked recursively,\n\
2845 or when the back end is in a partially-initialized state.\n\
2846 @code{cfun} might be @code{NULL} to indicate processing at top level,\n\
2847 outside of any function scope.",
2848 void, (tree decl), hook_void_tree)
2850 /* True if EXP should be placed in a "small data" section. */
2851 DEFHOOK
2852 (in_small_data_p,
2853 "Returns true if @var{exp} should be placed into a ``small data'' section.\n\
2854 The default version of this hook always returns false.",
2855 bool, (const_tree exp),
2856 hook_bool_const_tree_false)
2858 /* True if EXP names an object for which name resolution must resolve
2859 to the current executable or shared library. */
2860 DEFHOOK
2861 (binds_local_p,
2862 "Returns true if @var{exp} names an object for which name resolution\n\
2863 rules must resolve to the current ``module'' (dynamic shared library\n\
2864 or executable image).\n\
2866 The default version of this hook implements the name resolution rules\n\
2867 for ELF, which has a looser model of global name binding than other\n\
2868 currently supported object file formats.",
2869 bool, (const_tree exp),
2870 default_binds_local_p)
2872 /* Check if profiling code is before or after prologue. */
2873 DEFHOOK
2874 (profile_before_prologue,
2875 "It returns true if target wants profile code emitted before prologue.\n\n\
2876 The default version of this hook use the target macro\n\
2877 @code{PROFILE_BEFORE_PROLOGUE}.",
2878 bool, (void),
2879 default_profile_before_prologue)
2881 /* Return true if a leaf function should stay leaf even with profiling
2882 enabled. */
2883 DEFHOOK
2884 (keep_leaf_when_profiled,
2885 "This target hook returns true if the target wants the leaf flag for\
2886 the current function to stay true even if it calls mcount. This might\
2887 make sense for targets using the leaf flag only to determine whether a\
2888 stack frame needs to be generated or not and for which the call to\
2889 mcount is generated before the function prologue.",
2890 bool, (void),
2891 default_keep_leaf_when_profiled)
2893 /* Modify and return the identifier of a DECL's external name,
2894 originally identified by ID, as required by the target,
2895 (eg, append @nn to windows32 stdcall function names).
2896 The default is to return ID without modification. */
2897 DEFHOOK
2898 (mangle_decl_assembler_name,
2899 "Define this hook if you need to postprocess the assembler name generated\n\
2900 by target-independent code. The @var{id} provided to this hook will be\n\
2901 the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,\n\
2902 or the mangled name of the @var{decl} in C++). The return value of the\n\
2903 hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on\n\
2904 your target system. The default implementation of this hook just\n\
2905 returns the @var{id} provided.",
2906 tree, (tree decl, tree id),
2907 default_mangle_decl_assembler_name)
2909 /* Do something target-specific to record properties of the DECL into
2910 the associated SYMBOL_REF. */
2911 DEFHOOK
2912 (encode_section_info,
2913 "Define this hook if references to a symbol or a constant must be\n\
2914 treated differently depending on something about the variable or\n\
2915 function named by the symbol (such as what section it is in).\n\
2917 The hook is executed immediately after rtl has been created for\n\
2918 @var{decl}, which may be a variable or function declaration or\n\
2919 an entry in the constant pool. In either case, @var{rtl} is the\n\
2920 rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}\n\
2921 in this hook; that field may not have been initialized yet.\n\
2923 In the case of a constant, it is safe to assume that the rtl is\n\
2924 a @code{mem} whose address is a @code{symbol_ref}. Most decls\n\
2925 will also have this form, but that is not guaranteed. Global\n\
2926 register variables, for instance, will have a @code{reg} for their\n\
2927 rtl. (Normally the right thing to do with such unusual rtl is\n\
2928 leave it alone.)\n\
2930 The @var{new_decl_p} argument will be true if this is the first time\n\
2931 that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will\n\
2932 be false for subsequent invocations, which will happen for duplicate\n\
2933 declarations. Whether or not anything must be done for the duplicate\n\
2934 declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.\n\
2935 @var{new_decl_p} is always true when the hook is called for a constant.\n\
2937 @cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}\n\
2938 The usual thing for this hook to do is to record flags in the\n\
2939 @code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.\n\
2940 Historically, the name string was modified if it was necessary to\n\
2941 encode more than one bit of information, but this practice is now\n\
2942 discouraged; use @code{SYMBOL_REF_FLAGS}.\n\
2944 The default definition of this hook, @code{default_encode_section_info}\n\
2945 in @file{varasm.c}, sets a number of commonly-useful bits in\n\
2946 @code{SYMBOL_REF_FLAGS}. Check whether the default does what you need\n\
2947 before overriding it.",
2948 void, (tree decl, rtx rtl, int new_decl_p),
2949 default_encode_section_info)
2951 /* Undo the effects of encode_section_info on the symbol string. */
2952 DEFHOOK
2953 (strip_name_encoding,
2954 "Decode @var{name} and return the real name part, sans\n\
2955 the characters that @code{TARGET_ENCODE_SECTION_INFO}\n\
2956 may have added.",
2957 const char *, (const char *name),
2958 default_strip_name_encoding)
2960 /* If shift optabs for MODE are known to always truncate the shift count,
2961 return the mask that they apply. Return 0 otherwise. */
2962 DEFHOOK
2963 (shift_truncation_mask,
2964 "This function describes how the standard shift patterns for @var{mode}\n\
2965 deal with shifts by negative amounts or by more than the width of the mode.\n\
2966 @xref{shift patterns}.\n\
2968 On many machines, the shift patterns will apply a mask @var{m} to the\n\
2969 shift count, meaning that a fixed-width shift of @var{x} by @var{y} is\n\
2970 equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If\n\
2971 this is true for mode @var{mode}, the function should return @var{m},\n\
2972 otherwise it should return 0. A return value of 0 indicates that no\n\
2973 particular behavior is guaranteed.\n\
2975 Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does\n\
2976 @emph{not} apply to general shift rtxes; it applies only to instructions\n\
2977 that are generated by the named shift patterns.\n\
2979 The default implementation of this function returns\n\
2980 @code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}\n\
2981 and 0 otherwise. This definition is always safe, but if\n\
2982 @code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns\n\
2983 nevertheless truncate the shift count, you may get better code\n\
2984 by overriding it.",
2985 unsigned HOST_WIDE_INT, (machine_mode mode),
2986 default_shift_truncation_mask)
2988 /* Return the number of divisions in the given MODE that should be present,
2989 so that it is profitable to turn the division into a multiplication by
2990 the reciprocal. */
2991 DEFHOOK
2992 (min_divisions_for_recip_mul,
2993 "When @option{-ffast-math} is in effect, GCC tries to optimize\n\
2994 divisions by the same divisor, by turning them into multiplications by\n\
2995 the reciprocal. This target hook specifies the minimum number of divisions\n\
2996 that should be there for GCC to perform the optimization for a variable\n\
2997 of mode @var{mode}. The default implementation returns 3 if the machine\n\
2998 has an instruction for the division, and 2 if it does not.",
2999 unsigned int, (machine_mode mode),
3000 default_min_divisions_for_recip_mul)
3002 /* If the representation of integral MODE is such that values are
3003 always sign-extended to a wider mode MODE_REP then return
3004 SIGN_EXTEND. Return UNKNOWN otherwise. */
3005 /* Note that the return type ought to be RTX_CODE, but that's not
3006 necessarily defined at this point. */
3007 DEFHOOK
3008 (mode_rep_extended,
3009 "The representation of an integral mode can be such that the values\n\
3010 are always extended to a wider integral mode. Return\n\
3011 @code{SIGN_EXTEND} if values of @var{mode} are represented in\n\
3012 sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}\n\
3013 otherwise. (Currently, none of the targets use zero-extended\n\
3014 representation this way so unlike @code{LOAD_EXTEND_OP},\n\
3015 @code{TARGET_MODE_REP_EXTENDED} is expected to return either\n\
3016 @code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends\n\
3017 @var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next\n\
3018 widest integral mode and currently we take advantage of this fact.)\n\
3020 Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}\n\
3021 value even if the extension is not performed on certain hard registers\n\
3022 as long as for the @code{REGNO_REG_CLASS} of these hard registers\n\
3023 @code{CANNOT_CHANGE_MODE_CLASS} returns nonzero.\n\
3025 Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}\n\
3026 describe two related properties. If you define\n\
3027 @code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want\n\
3028 to define @code{LOAD_EXTEND_OP (mode)} to return the same type of\n\
3029 extension.\n\
3031 In order to enforce the representation of @code{mode},\n\
3032 @code{TRULY_NOOP_TRUNCATION} should return false when truncating to\n\
3033 @code{mode}.",
3034 int, (machine_mode mode, machine_mode rep_mode),
3035 default_mode_rep_extended)
3037 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
3038 DEFHOOK
3039 (valid_pointer_mode,
3040 "Define this to return nonzero if the port can handle pointers\n\
3041 with machine mode @var{mode}. The default version of this\n\
3042 hook returns true for both @code{ptr_mode} and @code{Pmode}.",
3043 bool, (machine_mode mode),
3044 default_valid_pointer_mode)
3046 /* Disambiguate with errno. */
3047 DEFHOOK
3048 (ref_may_alias_errno,
3049 "Define this to return nonzero if the memory reference @var{ref}\
3050 may alias with the system C library errno location. The default\
3051 version of this hook assumes the system C library errno location\
3052 is either a declaration of type int or accessed by dereferencing\
3053 a pointer to int.",
3054 bool, (struct ao_ref *ref),
3055 default_ref_may_alias_errno)
3057 /* Support for named address spaces. */
3058 #undef HOOK_PREFIX
3059 #define HOOK_PREFIX "TARGET_ADDR_SPACE_"
3060 HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)
3062 /* MODE to use for a pointer into another address space. */
3063 DEFHOOK
3064 (pointer_mode,
3065 "Define this to return the machine mode to use for pointers to\n\
3066 @var{address_space} if the target supports named address spaces.\n\
3067 The default version of this hook returns @code{ptr_mode} for the\n\
3068 generic address space only.",
3069 machine_mode, (addr_space_t address_space),
3070 default_addr_space_pointer_mode)
3072 /* MODE to use for an address in another address space. */
3073 DEFHOOK
3074 (address_mode,
3075 "Define this to return the machine mode to use for addresses in\n\
3076 @var{address_space} if the target supports named address spaces.\n\
3077 The default version of this hook returns @code{Pmode} for the\n\
3078 generic address space only.",
3079 machine_mode, (addr_space_t address_space),
3080 default_addr_space_address_mode)
3082 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
3083 in another address space. */
3084 DEFHOOK
3085 (valid_pointer_mode,
3086 "Define this to return nonzero if the port can handle pointers\n\
3087 with machine mode @var{mode} to address space @var{as}. This target\n\
3088 hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,\n\
3089 except that it includes explicit named address space support. The default\n\
3090 version of this hook returns true for the modes returned by either the\n\
3091 @code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}\n\
3092 target hooks for the given address space.",
3093 bool, (machine_mode mode, addr_space_t as),
3094 default_addr_space_valid_pointer_mode)
3096 /* True if an address is a valid memory address to a given named address
3097 space for a given mode. */
3098 DEFHOOK
3099 (legitimate_address_p,
3100 "Define this to return true if @var{exp} is a valid address for mode\n\
3101 @var{mode} in the named address space @var{as}. The @var{strict}\n\
3102 parameter says whether strict addressing is in effect after reload has\n\
3103 finished. This target hook is the same as the\n\
3104 @code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes\n\
3105 explicit named address space support.",
3106 bool, (machine_mode mode, rtx exp, bool strict, addr_space_t as),
3107 default_addr_space_legitimate_address_p)
3109 /* Return an updated address to convert an invalid pointer to a named
3110 address space to a valid one. If NULL_RTX is returned use machine
3111 independent methods to make the address valid. */
3112 DEFHOOK
3113 (legitimize_address,
3114 "Define this to modify an invalid address @var{x} to be a valid address\n\
3115 with mode @var{mode} in the named address space @var{as}. This target\n\
3116 hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,\n\
3117 except that it includes explicit named address space support.",
3118 rtx, (rtx x, rtx oldx, machine_mode mode, addr_space_t as),
3119 default_addr_space_legitimize_address)
3121 /* True if one named address space is a subset of another named address. */
3122 DEFHOOK
3123 (subset_p,
3124 "Define this to return whether the @var{subset} named address space is\n\
3125 contained within the @var{superset} named address space. Pointers to\n\
3126 a named address space that is a subset of another named address space\n\
3127 will be converted automatically without a cast if used together in\n\
3128 arithmetic operations. Pointers to a superset address space can be\n\
3129 converted to pointers to a subset address space via explicit casts.",
3130 bool, (addr_space_t subset, addr_space_t superset),
3131 default_addr_space_subset_p)
3133 /* Function to convert an rtl expression from one address space to another. */
3134 DEFHOOK
3135 (convert,
3136 "Define this to convert the pointer expression represented by the RTL\n\
3137 @var{op} with type @var{from_type} that points to a named address\n\
3138 space to a new pointer expression with type @var{to_type} that points\n\
3139 to a different named address space. When this hook it called, it is\n\
3140 guaranteed that one of the two address spaces is a subset of the other,\n\
3141 as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.",
3142 rtx, (rtx op, tree from_type, tree to_type),
3143 default_addr_space_convert)
3145 HOOK_VECTOR_END (addr_space)
3147 #undef HOOK_PREFIX
3148 #define HOOK_PREFIX "TARGET_"
3150 /* True if MODE is valid for the target. By "valid", we mean able to
3151 be manipulated in non-trivial ways. In particular, this means all
3152 the arithmetic is supported. */
3153 DEFHOOK
3154 (scalar_mode_supported_p,
3155 "Define this to return nonzero if the port is prepared to handle\n\
3156 insns involving scalar mode @var{mode}. For a scalar mode to be\n\
3157 considered supported, all the basic arithmetic and comparisons\n\
3158 must work.\n\
3160 The default version of this hook returns true for any mode\n\
3161 required to handle the basic C types (as defined by the port).\n\
3162 Included here are the double-word arithmetic supported by the\n\
3163 code in @file{optabs.c}.",
3164 bool, (machine_mode mode),
3165 default_scalar_mode_supported_p)
3167 /* Similarly for vector modes. "Supported" here is less strict. At
3168 least some operations are supported; need to check optabs or builtins
3169 for further details. */
3170 DEFHOOK
3171 (vector_mode_supported_p,
3172 "Define this to return nonzero if the port is prepared to handle\n\
3173 insns involving vector mode @var{mode}. At the very least, it\n\
3174 must have move patterns for this mode.",
3175 bool, (machine_mode mode),
3176 hook_bool_mode_false)
3178 DEFHOOK
3179 (vector_alignment,
3180 "This hook can be used to define the alignment for a vector of type\n\
3181 @var{type}, in order to comply with a platform ABI. The default is to\n\
3182 require natural alignment for vector types. The alignment returned by\n\
3183 this hook must be a power-of-two multiple of the default alignment of\n\
3184 the vector element type.",
3185 HOST_WIDE_INT, (const_tree type),
3186 default_vector_alignment)
3188 /* True if we should try to use a scalar mode to represent an array,
3189 overriding the usual MAX_FIXED_MODE limit. */
3190 DEFHOOK
3191 (array_mode_supported_p,
3192 "Return true if GCC should try to use a scalar mode to store an array\n\
3193 of @var{nelems} elements, given that each element has mode @var{mode}.\n\
3194 Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
3195 and allows GCC to use any defined integer mode.\n\
3197 One use of this hook is to support vector load and store operations\n\
3198 that operate on several homogeneous vectors. For example, ARM NEON\n\
3199 has operations like:\n\
3201 @smallexample\n\
3202 int8x8x3_t vld3_s8 (const int8_t *)\n\
3203 @end smallexample\n\
3205 where the return type is defined as:\n\
3207 @smallexample\n\
3208 typedef struct int8x8x3_t\n\
3209 @{\n\
3210 int8x8_t val[3];\n\
3211 @} int8x8x3_t;\n\
3212 @end smallexample\n\
3214 If this hook allows @code{val} to have a scalar mode, then\n\
3215 @code{int8x8x3_t} can have the same mode. GCC can then store\n\
3216 @code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
3217 bool, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3218 hook_bool_mode_uhwi_false)
3220 DEFHOOK
3221 (libgcc_floating_mode_supported_p,
3222 "Define this to return nonzero if libgcc provides support for the \n\
3223 floating-point mode @var{mode}, which is known to pass \n\
3224 @code{TARGET_SCALAR_MODE_SUPPORTED_P}. The default version of this \n\
3225 hook returns true for all of @code{SFmode}, @code{DFmode}, \n\
3226 @code{XFmode} and @code{TFmode}, if such modes exist.",
3227 bool, (machine_mode mode),
3228 default_libgcc_floating_mode_supported_p)
3230 /* Compute cost of moving data from a register of class FROM to one of
3231 TO, using MODE. */
3232 DEFHOOK
3233 (register_move_cost,
3234 "This target hook should return the cost of moving data of mode @var{mode}\n\
3235 from a register in class @var{from} to one in class @var{to}. The classes\n\
3236 are expressed using the enumeration values such as @code{GENERAL_REGS}.\n\
3237 A value of 2 is the default; other values are interpreted relative to\n\
3238 that.\n\
3240 It is not required that the cost always equal 2 when @var{from} is the\n\
3241 same as @var{to}; on some machines it is expensive to move between\n\
3242 registers if they are not general registers.\n\
3244 If reload sees an insn consisting of a single @code{set} between two\n\
3245 hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their\n\
3246 classes returns a value of 2, reload does not check to ensure that the\n\
3247 constraints of the insn are met. Setting a cost of other than 2 will\n\
3248 allow reload to verify that the constraints are met. You should do this\n\
3249 if the @samp{mov@var{m}} pattern's constraints do not allow such copying.\n\
3251 The default version of this function returns 2.",
3252 int, (machine_mode mode, reg_class_t from, reg_class_t to),
3253 default_register_move_cost)
3255 /* Compute cost of moving registers to/from memory. */
3256 /* ??? Documenting the argument types for this hook requires a GFDL
3257 license grant. Also, the documentation uses a different name for RCLASS. */
3258 DEFHOOK
3259 (memory_move_cost,
3260 "This target hook should return the cost of moving data of mode @var{mode}\n\
3261 between a register of class @var{rclass} and memory; @var{in} is @code{false}\n\
3262 if the value is to be written to memory, @code{true} if it is to be read in.\n\
3263 This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.\n\
3264 If moving between registers and memory is more expensive than between two\n\
3265 registers, you should add this target hook to express the relative cost.\n\
3267 If you do not add this target hook, GCC uses a default cost of 4 plus\n\
3268 the cost of copying via a secondary reload register, if one is\n\
3269 needed. If your machine requires a secondary reload register to copy\n\
3270 between memory and a register of @var{rclass} but the reload mechanism is\n\
3271 more complex than copying via an intermediate, use this target hook to\n\
3272 reflect the actual cost of the move.\n\
3274 GCC defines the function @code{memory_move_secondary_cost} if\n\
3275 secondary reloads are needed. It computes the costs due to copying via\n\
3276 a secondary register. If your machine copies from memory using a\n\
3277 secondary register in the conventional way but the default base value of\n\
3278 4 is not correct for your machine, use this target hook to add some other\n\
3279 value to the result of that function. The arguments to that function\n\
3280 are the same as to this target hook.",
3281 int, (machine_mode mode, reg_class_t rclass, bool in),
3282 default_memory_move_cost)
3284 DEFHOOK
3285 (use_by_pieces_infrastructure_p,
3286 "GCC will attempt several strategies when asked to copy between\n\
3287 two areas of memory, or to set, clear or store to memory, for example\n\
3288 when copying a @code{struct}. The @code{by_pieces} infrastructure\n\
3289 implements such memory operations as a sequence of load, store or move\n\
3290 insns. Alternate strategies are to expand the\n\
3291 @code{movmem} or @code{setmem} optabs, to emit a library call, or to emit\n\
3292 unit-by-unit, loop-based operations.\n\
3294 This target hook should return true if, for a memory operation with a\n\
3295 given @var{size} and @var{alignment}, using the @code{by_pieces}\n\
3296 infrastructure is expected to result in better code generation.\n\
3297 Both @var{size} and @var{alignment} are measured in terms of storage\n\
3298 units.\n\
3300 The parameter @var{op} is one of: @code{CLEAR_BY_PIECES},\n\
3301 @code{MOVE_BY_PIECES}, @code{SET_BY_PIECES}, @code{STORE_BY_PIECES}.\n\
3302 These describe the type of memory operation under consideration.\n\
3304 The parameter @var{speed_p} is true if the code is currently being\n\
3305 optimized for speed rather than size.\n\
3307 Returning true for higher values of @var{size} can improve code generation\n\
3308 for speed if the target does not provide an implementation of the\n\
3309 @code{movmem} or @code{setmem} standard names, if the @code{movmem} or\n\
3310 @code{setmem} implementation would be more expensive than a sequence of\n\
3311 insns, or if the overhead of a library call would dominate that of\n\
3312 the body of the memory operation.\n\
3314 Returning true for higher values of @code{size} may also cause an increase\n\
3315 in code size, for example where the number of insns emitted to perform a\n\
3316 move would be greater than that of a library call.",
3317 bool, (unsigned HOST_WIDE_INT size, unsigned int alignment,
3318 enum by_pieces_operation op, bool speed_p),
3319 default_use_by_pieces_infrastructure_p)
3321 /* True for MODE if the target expects that registers in this mode will
3322 be allocated to registers in a small register class. The compiler is
3323 allowed to use registers explicitly used in the rtl as spill registers
3324 but it should prevent extending the lifetime of these registers. */
3325 DEFHOOK
3326 (small_register_classes_for_mode_p,
3327 "Define this to return nonzero for machine modes for which the port has\n\
3328 small register classes. If this target hook returns nonzero for a given\n\
3329 @var{mode}, the compiler will try to minimize the lifetime of registers\n\
3330 in @var{mode}. The hook may be called with @code{VOIDmode} as argument.\n\
3331 In this case, the hook is expected to return nonzero if it returns nonzero\n\
3332 for any mode.\n\
3334 On some machines, it is risky to let hard registers live across arbitrary\n\
3335 insns. Typically, these machines have instructions that require values\n\
3336 to be in specific registers (like an accumulator), and reload will fail\n\
3337 if the required hard register is used for another purpose across such an\n\
3338 insn.\n\
3340 Passes before reload do not know which hard registers will be used\n\
3341 in an instruction, but the machine modes of the registers set or used in\n\
3342 the instruction are already known. And for some machines, register\n\
3343 classes are small for, say, integer registers but not for floating point\n\
3344 registers. For example, the AMD x86-64 architecture requires specific\n\
3345 registers for the legacy x86 integer instructions, but there are many\n\
3346 SSE registers for floating point operations. On such targets, a good\n\
3347 strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}\n\
3348 machine modes but zero for the SSE register classes.\n\
3350 The default version of this hook returns false for any mode. It is always\n\
3351 safe to redefine this hook to return with a nonzero value. But if you\n\
3352 unnecessarily define it, you will reduce the amount of optimizations\n\
3353 that can be performed in some cases. If you do not define this hook\n\
3354 to return a nonzero value when it is required, the compiler will run out\n\
3355 of spill registers and print a fatal error message.",
3356 bool, (machine_mode mode),
3357 hook_bool_mode_false)
3359 /* Register number for a flags register. Only needs to be defined if the
3360 target is constrainted to use post-reload comparison elimination. */
3361 DEFHOOKPOD
3362 (flags_regnum,
3363 "If the target has a dedicated flags register, and it needs to use the\
3364 post-reload comparison elimination pass, then this value should be set\
3365 appropriately.",
3366 unsigned int, INVALID_REGNUM)
3368 /* Compute a (partial) cost for rtx X. Return true if the complete
3369 cost has been computed, and false if subexpressions should be
3370 scanned. In either case, *TOTAL contains the cost result. */
3371 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
3372 not necessarily defined at this point. */
3373 DEFHOOK
3374 (rtx_costs,
3375 "This target hook describes the relative costs of RTL expressions.\n\
3377 The cost may depend on the precise form of the expression, which is\n\
3378 available for examination in @var{x}, and the fact that @var{x} appears\n\
3379 as operand @var{opno} of an expression with rtx code @var{outer_code}.\n\
3380 That is, the hook can assume that there is some rtx @var{y} such\n\
3381 that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that\n\
3382 either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or\n\
3383 (b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.\n\
3385 @var{code} is @var{x}'s expression code---redundant, since it can be\n\
3386 obtained with @code{GET_CODE (@var{x})}.\n\
3388 In implementing this hook, you can use the construct\n\
3389 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3390 instructions.\n\
3392 On entry to the hook, @code{*@var{total}} contains a default estimate\n\
3393 for the cost of the expression. The hook should modify this value as\n\
3394 necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}\n\
3395 for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus\n\
3396 operations, and @code{COSTS_N_INSNS (1)} for all other operations.\n\
3398 When optimizing for code size, i.e.@: when @code{speed} is\n\
3399 false, this target hook should be used to estimate the relative\n\
3400 size cost of an expression, again relative to @code{COSTS_N_INSNS}.\n\
3402 The hook returns true when all subexpressions of @var{x} have been\n\
3403 processed, and false when @code{rtx_cost} should recurse.",
3404 bool, (rtx x, int code, int outer_code, int opno, int *total, bool speed),
3405 hook_bool_rtx_int_int_int_intp_bool_false)
3407 /* Compute the cost of X, used as an address. Never called with
3408 invalid addresses. */
3409 DEFHOOK
3410 (address_cost,
3411 "This hook computes the cost of an addressing mode that contains\n\
3412 @var{address}. If not defined, the cost is computed from\n\
3413 the @var{address} expression and the @code{TARGET_RTX_COST} hook.\n\
3415 For most CISC machines, the default cost is a good approximation of the\n\
3416 true cost of the addressing mode. However, on RISC machines, all\n\
3417 instructions normally have the same length and execution time. Hence\n\
3418 all addresses will have equal costs.\n\
3420 In cases where more than one form of an address is known, the form with\n\
3421 the lowest cost will be used. If multiple forms have the same, lowest,\n\
3422 cost, the one that is the most complex will be used.\n\
3424 For example, suppose an address that is equal to the sum of a register\n\
3425 and a constant is used twice in the same basic block. When this macro\n\
3426 is not defined, the address will be computed in a register and memory\n\
3427 references will be indirect through that register. On machines where\n\
3428 the cost of the addressing mode containing the sum is no higher than\n\
3429 that of a simple indirect reference, this will produce an additional\n\
3430 instruction and possibly require an additional register. Proper\n\
3431 specification of this macro eliminates this overhead for such machines.\n\
3433 This hook is never called with an invalid address.\n\
3435 On machines where an address involving more than one register is as\n\
3436 cheap as an address computation involving only one register, defining\n\
3437 @code{TARGET_ADDRESS_COST} to reflect this can cause two registers to\n\
3438 be live over a region of code where only one would have been if\n\
3439 @code{TARGET_ADDRESS_COST} were not defined in that manner. This effect\n\
3440 should be considered in the definition of this macro. Equivalent costs\n\
3441 should probably only be given to addresses with different numbers of\n\
3442 registers on machines with lots of registers.",
3443 int, (rtx address, machine_mode mode, addr_space_t as, bool speed),
3444 default_address_cost)
3446 /* Return where to allocate pseudo for a given hard register initial value. */
3447 DEFHOOK
3448 (allocate_initial_value,
3449 "\n\
3450 When the initial value of a hard register has been copied in a pseudo\n\
3451 register, it is often not necessary to actually allocate another register\n\
3452 to this pseudo register, because the original hard register or a stack slot\n\
3453 it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}\n\
3454 is called at the start of register allocation once for each hard register\n\
3455 that had its initial value copied by using\n\
3456 @code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.\n\
3457 Possible values are @code{NULL_RTX}, if you don't want\n\
3458 to do any special allocation, a @code{REG} rtx---that would typically be\n\
3459 the hard register itself, if it is known not to be clobbered---or a\n\
3460 @code{MEM}.\n\
3461 If you are returning a @code{MEM}, this is only a hint for the allocator;\n\
3462 it might decide to use another register anyways.\n\
3463 You may use @code{current_function_is_leaf} or \n\
3464 @code{REG_N_SETS} in the hook to determine if the hard\n\
3465 register in question will not be clobbered.\n\
3466 The default value of this hook is @code{NULL}, which disables any special\n\
3467 allocation.",
3468 rtx, (rtx hard_reg), NULL)
3470 /* Return nonzero if evaluating UNSPEC X might cause a trap.
3471 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
3472 DEFHOOK
3473 (unspec_may_trap_p,
3474 "This target hook returns nonzero if @var{x}, an @code{unspec} or\n\
3475 @code{unspec_volatile} operation, might cause a trap. Targets can use\n\
3476 this hook to enhance precision of analysis for @code{unspec} and\n\
3477 @code{unspec_volatile} operations. You may call @code{may_trap_p_1}\n\
3478 to analyze inner elements of @var{x} in which case @var{flags} should be\n\
3479 passed along.",
3480 int, (const_rtx x, unsigned flags),
3481 default_unspec_may_trap_p)
3483 /* Given a register, this hook should return a parallel of registers
3484 to represent where to find the register pieces. Define this hook
3485 if the register and its mode are represented in Dwarf in
3486 non-contiguous locations, or if the register should be
3487 represented in more than one register in Dwarf. Otherwise, this
3488 hook should return NULL_RTX. */
3489 DEFHOOK
3490 (dwarf_register_span,
3491 "Given a register, this hook should return a parallel of registers to\n\
3492 represent where to find the register pieces. Define this hook if the\n\
3493 register and its mode are represented in Dwarf in non-contiguous\n\
3494 locations, or if the register should be represented in more than one\n\
3495 register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.\n\
3496 If not defined, the default is to return @code{NULL_RTX}.",
3497 rtx, (rtx reg),
3498 hook_rtx_rtx_null)
3500 /* Given a register return the mode of the corresponding DWARF frame
3501 register. */
3502 DEFHOOK
3503 (dwarf_frame_reg_mode,
3504 "Given a register, this hook should return the mode which the\n\
3505 corresponding Dwarf frame register should have. This is normally\n\
3506 used to return a smaller mode than the raw mode to prevent call\n\
3507 clobbered parts of a register altering the frame register size",
3508 machine_mode, (int regno),
3509 default_dwarf_frame_reg_mode)
3511 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
3512 entries not corresponding directly to registers below
3513 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
3514 code, given the address of the table. */
3515 DEFHOOK
3516 (init_dwarf_reg_sizes_extra,
3517 "If some registers are represented in Dwarf-2 unwind information in\n\
3518 multiple pieces, define this hook to fill in information about the\n\
3519 sizes of those pieces in the table used by the unwinder at runtime.\n\
3520 It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after\n\
3521 filling in a single size corresponding to each hard register;\n\
3522 @var{address} is the address of the table.",
3523 void, (tree address),
3524 hook_void_tree)
3526 /* Fetch the fixed register(s) which hold condition codes, for
3527 targets where it makes sense to look for duplicate assignments to
3528 the condition codes. This should return true if there is such a
3529 register, false otherwise. The arguments should be set to the
3530 fixed register numbers. Up to two condition code registers are
3531 supported. If there is only one for this target, the int pointed
3532 at by the second argument should be set to -1. */
3533 DEFHOOK
3534 (fixed_condition_code_regs,
3535 "On targets which do not use @code{(cc0)}, and which use a hard\n\
3536 register rather than a pseudo-register to hold condition codes, the\n\
3537 regular CSE passes are often not able to identify cases in which the\n\
3538 hard register is set to a common value. Use this hook to enable a\n\
3539 small pass which optimizes such cases. This hook should return true\n\
3540 to enable this pass, and it should set the integers to which its\n\
3541 arguments point to the hard register numbers used for condition codes.\n\
3542 When there is only one such register, as is true on most systems, the\n\
3543 integer pointed to by @var{p2} should be set to\n\
3544 @code{INVALID_REGNUM}.\n\
3546 The default version of this hook returns false.",
3547 bool, (unsigned int *p1, unsigned int *p2),
3548 hook_bool_uintp_uintp_false)
3550 /* If two condition code modes are compatible, return a condition
3551 code mode which is compatible with both, such that a comparison
3552 done in the returned mode will work for both of the original
3553 modes. If the condition code modes are not compatible, return
3554 VOIDmode. */
3555 DEFHOOK
3556 (cc_modes_compatible,
3557 "On targets which use multiple condition code modes in class\n\
3558 @code{MODE_CC}, it is sometimes the case that a comparison can be\n\
3559 validly done in more than one mode. On such a system, define this\n\
3560 target hook to take two mode arguments and to return a mode in which\n\
3561 both comparisons may be validly done. If there is no such mode,\n\
3562 return @code{VOIDmode}.\n\
3564 The default version of this hook checks whether the modes are the\n\
3565 same. If they are, it returns that mode. If they are different, it\n\
3566 returns @code{VOIDmode}.",
3567 machine_mode, (machine_mode m1, machine_mode m2),
3568 default_cc_modes_compatible)
3570 /* Do machine-dependent code transformations. Called just before
3571 delayed-branch scheduling. */
3572 DEFHOOK
3573 (machine_dependent_reorg,
3574 "If non-null, this hook performs a target-specific pass over the\n\
3575 instruction stream. The compiler will run it at all optimization levels,\n\
3576 just before the point at which it normally does delayed-branch scheduling.\n\
3578 The exact purpose of the hook varies from target to target. Some use\n\
3579 it to do transformations that are necessary for correctness, such as\n\
3580 laying out in-function constant pools or avoiding hardware hazards.\n\
3581 Others use it as an opportunity to do some machine-dependent optimizations.\n\
3583 You need not implement the hook if it has nothing to do. The default\n\
3584 definition is null.",
3585 void, (void), NULL)
3587 /* Create the __builtin_va_list type. */
3588 DEFHOOK
3589 (build_builtin_va_list,
3590 "This hook returns a type node for @code{va_list} for the target.\n\
3591 The default version of the hook returns @code{void*}.",
3592 tree, (void),
3593 std_build_builtin_va_list)
3595 /* Enumerate the va list variants. */
3596 DEFHOOK
3597 (enum_va_list_p,
3598 "This target hook is used in function @code{c_common_nodes_and_builtins}\n\
3599 to iterate through the target specific builtin types for va_list. The\n\
3600 variable @var{idx} is used as iterator. @var{pname} has to be a pointer\n\
3601 to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed\n\
3602 variable.\n\
3603 The arguments @var{pname} and @var{ptree} are used to store the result of\n\
3604 this macro and are set to the name of the va_list builtin type and its\n\
3605 internal type.\n\
3606 If the return value of this macro is zero, then there is no more element.\n\
3607 Otherwise the @var{IDX} should be increased for the next call of this\n\
3608 macro to iterate through all types.",
3609 int, (int idx, const char **pname, tree *ptree),
3610 NULL)
3612 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
3613 DEFHOOK
3614 (fn_abi_va_list,
3615 "This hook returns the va_list type of the calling convention specified by\n\
3616 @var{fndecl}.\n\
3617 The default version of this hook returns @code{va_list_type_node}.",
3618 tree, (tree fndecl),
3619 std_fn_abi_va_list)
3621 /* Get the __builtin_va_list type dependent on input type. */
3622 DEFHOOK
3623 (canonical_va_list_type,
3624 "This hook returns the va_list type of the calling convention specified by the\n\
3625 type of @var{type}. If @var{type} is not a valid va_list type, it returns\n\
3626 @code{NULL_TREE}.",
3627 tree, (tree type),
3628 std_canonical_va_list_type)
3630 /* ??? Documenting this hook requires a GFDL license grant. */
3631 DEFHOOK_UNDOC
3632 (expand_builtin_va_start,
3633 "Expand the @code{__builtin_va_start} builtin.",
3634 void, (tree valist, rtx nextarg), NULL)
3636 /* Gimplifies a VA_ARG_EXPR. */
3637 DEFHOOK
3638 (gimplify_va_arg_expr,
3639 "This hook performs target-specific gimplification of\n\
3640 @code{VA_ARG_EXPR}. The first two parameters correspond to the\n\
3641 arguments to @code{va_arg}; the latter two are as in\n\
3642 @code{gimplify.c:gimplify_expr}.",
3643 tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
3644 std_gimplify_va_arg_expr)
3646 /* Validity-checking routines for PCH files, target-specific.
3647 get_pch_validity returns a pointer to the data to be stored,
3648 and stores the size in its argument. pch_valid_p gets the same
3649 information back and returns NULL if the PCH is valid,
3650 or an error message if not. */
3651 DEFHOOK
3652 (get_pch_validity,
3653 "This hook returns a pointer to the data needed by\n\
3654 @code{TARGET_PCH_VALID_P} and sets\n\
3655 @samp{*@var{sz}} to the size of the data in bytes.",
3656 void *, (size_t *sz),
3657 default_get_pch_validity)
3659 DEFHOOK
3660 (pch_valid_p,
3661 "This hook checks whether the options used to create a PCH file are\n\
3662 compatible with the current settings. It returns @code{NULL}\n\
3663 if so and a suitable error message if not. Error messages will\n\
3664 be presented to the user and must be localized using @samp{_(@var{msg})}.\n\
3666 @var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}\n\
3667 when the PCH file was created and @var{sz} is the size of that data in bytes.\n\
3668 It's safe to assume that the data was created by the same version of the\n\
3669 compiler, so no format checking is needed.\n\
3671 The default definition of @code{default_pch_valid_p} should be\n\
3672 suitable for most targets.",
3673 const char *, (const void *data, size_t sz),
3674 default_pch_valid_p)
3676 DEFHOOK
3677 (prepare_pch_save,
3678 "Called before writing out a PCH file. If the target has some\n\
3679 garbage-collected data that needs to be in a particular state on PCH loads,\n\
3680 it can use this hook to enforce that state. Very few targets need\n\
3681 to do anything here.",
3682 void, (void),
3683 hook_void_void)
3685 /* If nonnull, this function checks whether a PCH file with the
3686 given set of target flags can be used. It returns NULL if so,
3687 otherwise it returns an error message. */
3688 DEFHOOK
3689 (check_pch_target_flags,
3690 "If this hook is nonnull, the default implementation of\n\
3691 @code{TARGET_PCH_VALID_P} will use it to check for compatible values\n\
3692 of @code{target_flags}. @var{pch_flags} specifies the value that\n\
3693 @code{target_flags} had when the PCH file was created. The return\n\
3694 value is the same as for @code{TARGET_PCH_VALID_P}.",
3695 const char *, (int pch_flags), NULL)
3697 /* True if the compiler should give an enum type only as many
3698 bytes as it takes to represent the range of possible values of
3699 that type. */
3700 DEFHOOK
3701 (default_short_enums,
3702 "This target hook should return true if the compiler should give an\n\
3703 @code{enum} type only as many bytes as it takes to represent the range\n\
3704 of possible values of that type. It should return false if all\n\
3705 @code{enum} types should be allocated like @code{int}.\n\
3707 The default is to return false.",
3708 bool, (void),
3709 hook_bool_void_false)
3711 /* This target hook returns an rtx that is used to store the address
3712 of the current frame into the built-in setjmp buffer. */
3713 DEFHOOK
3714 (builtin_setjmp_frame_value,
3715 "This target hook should return an rtx that is used to store\n\
3716 the address of the current frame into the built in @code{setjmp} buffer.\n\
3717 The default value, @code{virtual_stack_vars_rtx}, is correct for most\n\
3718 machines. One reason you may need to define this target hook is if\n\
3719 @code{hard_frame_pointer_rtx} is the appropriate value on your machine.",
3720 rtx, (void),
3721 default_builtin_setjmp_frame_value)
3723 /* This target hook should add STRING_CST trees for any hard regs
3724 the port wishes to automatically clobber for an asm. */
3725 DEFHOOK
3726 (md_asm_clobbers,
3727 "This target hook should add to @var{clobbers} @code{STRING_CST} trees for\n\
3728 any hard regs the port wishes to automatically clobber for an asm.\n\
3729 It should return the result of the last @code{tree_cons} used to add a\n\
3730 clobber. The @var{outputs}, @var{inputs} and @var{clobber} lists are the\n\
3731 corresponding parameters to the asm and may be inspected to avoid\n\
3732 clobbering a register that is an input or output of the asm. You can use\n\
3733 @code{tree_overlaps_hard_reg_set}, declared in @file{tree.h}, to test\n\
3734 for overlap with regards to asm-declared registers.",
3735 tree, (tree outputs, tree inputs, tree clobbers),
3736 hook_tree_tree_tree_tree_3rd_identity)
3738 /* This target hook allows the backend to specify a calling convention
3739 in the debug information. This function actually returns an
3740 enum dwarf_calling_convention, but because of forward declarations
3741 and not wanting to include dwarf2.h everywhere target.h is included
3742 the function is being declared as an int. */
3743 DEFHOOK
3744 (dwarf_calling_convention,
3745 "Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to\n\
3746 be emitted for each function. Instead of an integer return the enum\n\
3747 value for the @code{DW_CC_} tag.",
3748 int, (const_tree function),
3749 hook_int_const_tree_0)
3751 /* This target hook allows the backend to emit frame-related insns that
3752 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
3753 engine will invoke it on insns of the form
3754 (set (reg) (unspec [...] UNSPEC_INDEX))
3756 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
3757 to let the backend emit the call frame instructions. */
3758 DEFHOOK
3759 (dwarf_handle_frame_unspec,
3760 "This target hook allows the backend to emit frame-related insns that\n\
3761 contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging\n\
3762 info engine will invoke it on insns of the form\n\
3763 @smallexample\n\
3764 (set (reg) (unspec [@dots{}] UNSPEC_INDEX))\n\
3765 @end smallexample\n\
3766 and\n\
3767 @smallexample\n\
3768 (set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).\n\
3769 @end smallexample\n\
3770 to let the backend emit the call frame instructions. @var{label} is\n\
3771 the CFI label attached to the insn, @var{pattern} is the pattern of\n\
3772 the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.",
3773 void, (const char *label, rtx pattern, int index), NULL)
3775 /* ??? Documenting this hook requires a GFDL license grant. */
3776 DEFHOOK_UNDOC
3777 (stdarg_optimize_hook,
3778 "Perform architecture specific checking of statements gimplified\
3779 from @code{VA_ARG_EXPR}. @var{stmt} is the statement. Returns true if\
3780 the statement doesn't need to be checked for @code{va_list} references.",
3781 bool, (struct stdarg_info *ai, const_gimple stmt), NULL)
3783 /* This target hook allows the operating system to override the DECL
3784 that represents the external variable that contains the stack
3785 protection guard variable. The type of this DECL is ptr_type_node. */
3786 DEFHOOK
3787 (stack_protect_guard,
3788 "This hook returns a @code{DECL} node for the external variable to use\n\
3789 for the stack protection guard. This variable is initialized by the\n\
3790 runtime to some random value and is used to initialize the guard value\n\
3791 that is placed at the top of the local stack frame. The type of this\n\
3792 variable must be @code{ptr_type_node}.\n\
3794 The default version of this hook creates a variable called\n\
3795 @samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.",
3796 tree, (void),
3797 default_stack_protect_guard)
3799 /* This target hook allows the operating system to override the CALL_EXPR
3800 that is invoked when a check vs the guard variable fails. */
3801 DEFHOOK
3802 (stack_protect_fail,
3803 "This hook returns a @code{CALL_EXPR} that alerts the runtime that the\n\
3804 stack protect guard variable has been modified. This expression should\n\
3805 involve a call to a @code{noreturn} function.\n\
3807 The default version of this hook invokes a function called\n\
3808 @samp{__stack_chk_fail}, taking no arguments. This function is\n\
3809 normally defined in @file{libgcc2.c}.",
3810 tree, (void),
3811 default_external_stack_protect_fail)
3813 DEFHOOK
3814 (can_use_doloop_p,
3815 "Return true if it is possible to use low-overhead loops (@code{doloop_end}\n\
3816 and @code{doloop_begin}) for a particular loop. @var{iterations} gives the\n\
3817 exact number of iterations, or 0 if not known. @var{iterations_max} gives\n\
3818 the maximum number of iterations, or 0 if not known. @var{loop_depth} is\n\
3819 the nesting depth of the loop, with 1 for innermost loops, 2 for loops that\n\
3820 contain innermost loops, and so on. @var{entered_at_top} is true if the\n\
3821 loop is only entered from the top.\n\
3823 This hook is only used if @code{doloop_end} is available. The default\n\
3824 implementation returns true. You can use @code{can_use_doloop_if_innermost}\n\
3825 if the loop must be the innermost, and if there are no other restrictions.",
3826 bool, (const widest_int &iterations, const widest_int &iterations_max,
3827 unsigned int loop_depth, bool entered_at_top),
3828 hook_bool_wint_wint_uint_bool_true)
3830 /* Returns NULL if target supports the insn within a doloop block,
3831 otherwise it returns an error message. */
3832 DEFHOOK
3833 (invalid_within_doloop,
3834 "\n\
3835 Take an instruction in @var{insn} and return NULL if it is valid within a\n\
3836 low-overhead loop, otherwise return a string explaining why doloop\n\
3837 could not be applied.\n\
3839 Many targets use special registers for low-overhead looping. For any\n\
3840 instruction that clobbers these this function should return a string indicating\n\
3841 the reason why the doloop could not be applied.\n\
3842 By default, the RTL loop optimizer does not use a present doloop pattern for\n\
3843 loops containing function calls or branch on table instructions.",
3844 const char *, (const rtx_insn *insn),
3845 default_invalid_within_doloop)
3847 /* Returns true for a legitimate combined insn. */
3848 DEFHOOK
3849 (legitimate_combined_insn,
3850 "Take an instruction in @var{insn} and return @code{false} if the instruction\
3851 is not appropriate as a combination of two or more instructions. The\
3852 default is to accept all instructions.",
3853 bool, (rtx_insn *insn),
3854 hook_bool_rtx_insn_true)
3856 DEFHOOK
3857 (valid_dllimport_attribute_p,
3858 "@var{decl} is a variable or function with @code{__attribute__((dllimport))}\
3859 specified. Use this hook if the target needs to add extra validation\
3860 checks to @code{handle_dll_attribute}.",
3861 bool, (const_tree decl),
3862 hook_bool_const_tree_true)
3864 /* If non-zero, align constant anchors in CSE to a multiple of this
3865 value. */
3866 DEFHOOKPOD
3867 (const_anchor,
3868 "On some architectures it can take multiple instructions to synthesize\n\
3869 a constant. If there is another constant already in a register that\n\
3870 is close enough in value then it is preferable that the new constant\n\
3871 is computed from this register using immediate addition or\n\
3872 subtraction. We accomplish this through CSE. Besides the value of\n\
3873 the constant we also add a lower and an upper constant anchor to the\n\
3874 available expressions. These are then queried when encountering new\n\
3875 constants. The anchors are computed by rounding the constant up and\n\
3876 down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.\n\
3877 @code{TARGET_CONST_ANCHOR} should be the maximum positive value\n\
3878 accepted by immediate-add plus one. We currently assume that the\n\
3879 value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on\n\
3880 MIPS, where add-immediate takes a 16-bit signed value,\n\
3881 @code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value\n\
3882 is zero, which disables this optimization.",
3883 unsigned HOST_WIDE_INT, 0)
3885 /* Defines, which target-dependent bits (upper 16) are used by port */
3886 DEFHOOK
3887 (memmodel_check,
3888 "Validate target specific memory model mask bits. When NULL no target specific\n\
3889 memory model bits are allowed.",
3890 unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)
3892 /* Defines an offset bitwise ored into shifted address to get corresponding
3893 Address Sanitizer shadow address, or -1 if Address Sanitizer is not
3894 supported by the target. */
3895 DEFHOOK
3896 (asan_shadow_offset,
3897 "Return the offset bitwise ored into shifted address to get corresponding\n\
3898 Address Sanitizer shadow memory address. NULL if Address Sanitizer is not\n\
3899 supported by the target.",
3900 unsigned HOST_WIDE_INT, (void),
3901 NULL)
3903 /* Functions relating to calls - argument passing, returns, etc. */
3904 /* Members of struct call have no special macro prefix. */
3905 HOOK_VECTOR (TARGET_CALLS, calls)
3907 DEFHOOK
3908 (promote_function_mode,
3909 "Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or\n\
3910 function return values. The target hook should return the new mode\n\
3911 and possibly change @code{*@var{punsignedp}} if the promotion should\n\
3912 change signedness. This function is called only for scalar @emph{or\n\
3913 pointer} types.\n\
3915 @var{for_return} allows to distinguish the promotion of arguments and\n\
3916 return values. If it is @code{1}, a return value is being promoted and\n\
3917 @code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.\n\
3918 If it is @code{2}, the returned mode should be that of the register in\n\
3919 which an incoming parameter is copied, or the outgoing result is computed;\n\
3920 then the hook should return the same mode as @code{promote_mode}, though\n\
3921 the signedness may be different.\n\
3923 @var{type} can be NULL when promoting function arguments of libcalls.\n\
3925 The default is to not promote arguments and return values. You can\n\
3926 also define the hook to @code{default_promote_function_mode_always_promote}\n\
3927 if you would like to apply the same rules given by @code{PROMOTE_MODE}.",
3928 machine_mode, (const_tree type, machine_mode mode, int *punsignedp,
3929 const_tree funtype, int for_return),
3930 default_promote_function_mode)
3932 DEFHOOK
3933 (promote_prototypes,
3934 "This target hook returns @code{true} if an argument declared in a\n\
3935 prototype as an integral type smaller than @code{int} should actually be\n\
3936 passed as an @code{int}. In addition to avoiding errors in certain\n\
3937 cases of mismatch, it also makes for better code on certain machines.\n\
3938 The default is to not promote prototypes.",
3939 bool, (const_tree fntype),
3940 hook_bool_const_tree_false)
3942 DEFHOOK
3943 (struct_value_rtx,
3944 "This target hook should return the location of the structure value\n\
3945 address (normally a @code{mem} or @code{reg}), or 0 if the address is\n\
3946 passed as an ``invisible'' first argument. Note that @var{fndecl} may\n\
3947 be @code{NULL}, for libcalls. You do not need to define this target\n\
3948 hook if the address is always passed as an ``invisible'' first\n\
3949 argument.\n\
3951 On some architectures the place where the structure value address\n\
3952 is found by the called function is not the same place that the\n\
3953 caller put it. This can be due to register windows, or it could\n\
3954 be because the function prologue moves it to a different place.\n\
3955 @var{incoming} is @code{1} or @code{2} when the location is needed in\n\
3956 the context of the called function, and @code{0} in the context of\n\
3957 the caller.\n\
3959 If @var{incoming} is nonzero and the address is to be found on the\n\
3960 stack, return a @code{mem} which refers to the frame pointer. If\n\
3961 @var{incoming} is @code{2}, the result is being used to fetch the\n\
3962 structure value address at the beginning of a function. If you need\n\
3963 to emit adjusting code, you should do it at this point.",
3964 rtx, (tree fndecl, int incoming),
3965 hook_rtx_tree_int_null)
3967 DEFHOOKPOD
3968 (omit_struct_return_reg,
3969 "Normally, when a function returns a structure by memory, the address\n\
3970 is passed as an invisible pointer argument, but the compiler also\n\
3971 arranges to return the address from the function like it would a normal\n\
3972 pointer return value. Define this to true if that behaviour is\n\
3973 undesirable on your target.",
3974 bool, false)
3976 DEFHOOK
3977 (return_in_memory,
3978 "This target hook should return a nonzero value to say to return the\n\
3979 function value in memory, just as large structures are always returned.\n\
3980 Here @var{type} will be the data type of the value, and @var{fntype}\n\
3981 will be the type of the function doing the returning, or @code{NULL} for\n\
3982 libcalls.\n\
3984 Note that values of mode @code{BLKmode} must be explicitly handled\n\
3985 by this function. Also, the option @option{-fpcc-struct-return}\n\
3986 takes effect regardless of this macro. On most systems, it is\n\
3987 possible to leave the hook undefined; this causes a default\n\
3988 definition to be used, whose value is the constant 1 for @code{BLKmode}\n\
3989 values, and 0 otherwise.\n\
3991 Do not use this hook to indicate that structures and unions should always\n\
3992 be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}\n\
3993 to indicate this.",
3994 bool, (const_tree type, const_tree fntype),
3995 default_return_in_memory)
3997 DEFHOOK
3998 (return_in_msb,
3999 "This hook should return true if values of type @var{type} are returned\n\
4000 at the most significant end of a register (in other words, if they are\n\
4001 padded at the least significant end). You can assume that @var{type}\n\
4002 is returned in a register; the caller is required to check this.\n\
4004 Note that the register provided by @code{TARGET_FUNCTION_VALUE} must\n\
4005 be able to hold the complete return value. For example, if a 1-, 2-\n\
4006 or 3-byte structure is returned at the most significant end of a\n\
4007 4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an\n\
4008 @code{SImode} rtx.",
4009 bool, (const_tree type),
4010 hook_bool_const_tree_false)
4012 /* Return true if a parameter must be passed by reference. TYPE may
4013 be null if this is a libcall. CA may be null if this query is
4014 from __builtin_va_arg. */
4015 DEFHOOK
4016 (pass_by_reference,
4017 "This target hook should return @code{true} if an argument at the\n\
4018 position indicated by @var{cum} should be passed by reference. This\n\
4019 predicate is queried after target independent reasons for being\n\
4020 passed by reference, such as @code{TREE_ADDRESSABLE (type)}.\n\
4022 If the hook returns true, a copy of that argument is made in memory and a\n\
4023 pointer to the argument is passed instead of the argument itself.\n\
4024 The pointer is passed in whatever way is appropriate for passing a pointer\n\
4025 to that type.",
4026 bool,
4027 (cumulative_args_t cum, machine_mode mode, const_tree type, bool named),
4028 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
4030 DEFHOOK
4031 (expand_builtin_saveregs,
4032 "If defined, this hook produces the machine-specific code for a call to\n\
4033 @code{__builtin_saveregs}. This code will be moved to the very\n\
4034 beginning of the function, before any parameter access are made. The\n\
4035 return value of this function should be an RTX that contains the value\n\
4036 to use as the return of @code{__builtin_saveregs}.",
4037 rtx, (void),
4038 default_expand_builtin_saveregs)
4040 /* Returns pretend_argument_size. */
4041 DEFHOOK
4042 (setup_incoming_varargs,
4043 "This target hook offers an alternative to using\n\
4044 @code{__builtin_saveregs} and defining the hook\n\
4045 @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous\n\
4046 register arguments into the stack so that all the arguments appear to\n\
4047 have been passed consecutively on the stack. Once this is done, you can\n\
4048 use the standard implementation of varargs that works for machines that\n\
4049 pass all their arguments on the stack.\n\
4051 The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data\n\
4052 structure, containing the values that are obtained after processing the\n\
4053 named arguments. The arguments @var{mode} and @var{type} describe the\n\
4054 last named argument---its machine mode and its data type as a tree node.\n\
4056 The target hook should do two things: first, push onto the stack all the\n\
4057 argument registers @emph{not} used for the named arguments, and second,\n\
4058 store the size of the data thus pushed into the @code{int}-valued\n\
4059 variable pointed to by @var{pretend_args_size}. The value that you\n\
4060 store here will serve as additional offset for setting up the stack\n\
4061 frame.\n\
4063 Because you must generate code to push the anonymous arguments at\n\
4064 compile time without knowing their data types,\n\
4065 @code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that\n\
4066 have just a single category of argument register and use it uniformly\n\
4067 for all data types.\n\
4069 If the argument @var{second_time} is nonzero, it means that the\n\
4070 arguments of the function are being analyzed for the second time. This\n\
4071 happens for an inline function, which is not actually compiled until the\n\
4072 end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should\n\
4073 not generate any instructions in this case.",
4074 void, (cumulative_args_t args_so_far, machine_mode mode, tree type,
4075 int *pretend_args_size, int second_time),
4076 default_setup_incoming_varargs)
4078 DEFHOOK
4079 (load_bounds_for_arg,
4080 "This hook is used by expand pass to emit insn to load bounds of\n\
4081 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4082 bounds of @var{arg} are not passed in register. If @var{slot} is a\n\
4083 memory, then bounds are loaded as for regular pointer loaded from\n\
4084 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4085 constant holding number of the target dependent special slot which\n\
4086 should be used to obtain bounds. Hook returns RTX holding loaded bounds.",
4087 rtx, (rtx slot, rtx arg, rtx slot_no),
4088 default_load_bounds_for_arg)
4090 DEFHOOK
4091 (store_bounds_for_arg,
4092 "This hook is used by expand pass to emit insns to store @var{bounds} of\n\
4093 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4094 @var{bounds} of @var{arg} are not passed in register. If @var{slot} is a\n\
4095 memory, then @var{bounds} are stored as for regular pointer stored in\n\
4096 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4097 constant holding number of the target dependent special slot which\n\
4098 should be used to store @var{bounds}.",
4099 void, (rtx arg, rtx slot, rtx bounds, rtx slot_no),
4100 default_store_bounds_for_arg)
4102 DEFHOOK
4103 (load_returned_bounds,
4104 "This hook is used by expand pass to emit insn to load bounds\n\
4105 returned by function call in @var{slot}. Hook returns RTX holding\n\
4106 loaded bounds.",
4107 rtx, (rtx slot),
4108 default_load_returned_bounds)
4110 DEFHOOK
4111 (store_returned_bounds,
4112 "This hook is used by expand pass to emit insn to store @var{bounds}\n\
4113 returned by function call into @var{slot}.",
4114 void, (rtx slot, rtx bounds),
4115 default_store_returned_bounds)
4117 DEFHOOK
4118 (setup_incoming_vararg_bounds,
4119 "Use it to store bounds for anonymous register arguments stored\n\
4120 into the stack. Arguments meaning is similar to\n\
4121 @code{TARGET_SETUP_INCOMING_VARARGS}.",
4122 void, (cumulative_args_t args_so_far, enum machine_mode mode, tree type,
4123 int *pretend_args_size, int second_time),
4124 default_setup_incoming_vararg_bounds)
4126 DEFHOOK
4127 (call_args,
4128 "While generating RTL for a function call, this target hook is invoked once\n\
4129 for each argument passed to the function, either a register returned by\n\
4130 @code{TARGET_FUNCTION_ARG} or a memory location. It is called just\n\
4131 before the point where argument registers are stored. The type of the\n\
4132 function to be called is also passed as the second argument; it is\n\
4133 @code{NULL_TREE} for libcalls. The @code{TARGET_END_CALL_ARGS} hook is\n\
4134 invoked just after the code to copy the return reg has been emitted.\n\
4135 This functionality can be used to perform special setup of call argument\n\
4136 registers if a target needs it.\n\
4137 For functions without arguments, the hook is called once with @code{pc_rtx}\n\
4138 passed instead of an argument register.\n\
4139 Most ports do not need to implement anything for this hook.",
4140 void, (rtx, tree),
4141 hook_void_rtx_tree)
4143 DEFHOOK
4144 (end_call_args,
4145 "This target hook is invoked while generating RTL for a function call,\n\
4146 just after the point where the return reg is copied into a pseudo. It\n\
4147 signals that all the call argument and return registers for the just\n\
4148 emitted call are now no longer in use.\n\
4149 Most ports do not need to implement anything for this hook.",
4150 void, (void),
4151 hook_void_void)
4153 DEFHOOK
4154 (strict_argument_naming,
4155 "Define this hook to return @code{true} if the location where a function\n\
4156 argument is passed depends on whether or not it is a named argument.\n\
4158 This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}\n\
4159 is set for varargs and stdarg functions. If this hook returns\n\
4160 @code{true}, the @var{named} argument is always true for named\n\
4161 arguments, and false for unnamed arguments. If it returns @code{false},\n\
4162 but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},\n\
4163 then all arguments are treated as named. Otherwise, all named arguments\n\
4164 except the last are treated as named.\n\
4166 You need not define this hook if it always returns @code{false}.",
4167 bool, (cumulative_args_t ca),
4168 hook_bool_CUMULATIVE_ARGS_false)
4170 /* Returns true if we should use
4171 targetm.calls.setup_incoming_varargs() and/or
4172 targetm.calls.strict_argument_naming(). */
4173 DEFHOOK
4174 (pretend_outgoing_varargs_named,
4175 "If you need to conditionally change ABIs so that one works with\n\
4176 @code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither\n\
4177 @code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was\n\
4178 defined, then define this hook to return @code{true} if\n\
4179 @code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.\n\
4180 Otherwise, you should not define this hook.",
4181 bool, (cumulative_args_t ca),
4182 default_pretend_outgoing_varargs_named)
4184 /* Given a complex type T, return true if a parameter of type T
4185 should be passed as two scalars. */
4186 DEFHOOK
4187 (split_complex_arg,
4188 "This hook should return true if parameter of type @var{type} are passed\n\
4189 as two scalar parameters. By default, GCC will attempt to pack complex\n\
4190 arguments into the target's word size. Some ABIs require complex arguments\n\
4191 to be split and treated as their individual components. For example, on\n\
4192 AIX64, complex floats should be passed in a pair of floating point\n\
4193 registers, even though a complex float would fit in one 64-bit floating\n\
4194 point register.\n\
4196 The default value of this hook is @code{NULL}, which is treated as always\n\
4197 false.",
4198 bool, (const_tree type), NULL)
4200 /* Return true if type T, mode MODE, may not be passed in registers,
4201 but must be passed on the stack. */
4202 /* ??? This predicate should be applied strictly after pass-by-reference.
4203 Need audit to verify that this is the case. */
4204 DEFHOOK
4205 (must_pass_in_stack,
4206 "This target hook should return @code{true} if we should not pass @var{type}\n\
4207 solely in registers. The file @file{expr.h} defines a\n\
4208 definition that is usually appropriate, refer to @file{expr.h} for additional\n\
4209 documentation.",
4210 bool, (machine_mode mode, const_tree type),
4211 must_pass_in_stack_var_size_or_pad)
4213 /* Return true if type TYPE, mode MODE, which is passed by reference,
4214 should have the object copy generated by the callee rather than
4215 the caller. It is never called for TYPE requiring constructors. */
4216 DEFHOOK
4217 (callee_copies,
4218 "The function argument described by the parameters to this hook is\n\
4219 known to be passed by reference. The hook should return true if the\n\
4220 function argument should be copied by the callee instead of copied\n\
4221 by the caller.\n\
4223 For any argument for which the hook returns true, if it can be\n\
4224 determined that the argument is not modified, then a copy need\n\
4225 not be generated.\n\
4227 The default version of this hook always returns false.",
4228 bool,
4229 (cumulative_args_t cum, machine_mode mode, const_tree type, bool named),
4230 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
4232 /* Return zero for arguments passed entirely on the stack or entirely
4233 in registers. If passed in both, return the number of bytes passed
4234 in registers; the balance is therefore passed on the stack. */
4235 DEFHOOK
4236 (arg_partial_bytes,
4237 "This target hook returns the number of bytes at the beginning of an\n\
4238 argument that must be put in registers. The value must be zero for\n\
4239 arguments that are passed entirely in registers or that are entirely\n\
4240 pushed on the stack.\n\
4242 On some machines, certain arguments must be passed partially in\n\
4243 registers and partially in memory. On these machines, typically the\n\
4244 first few words of arguments are passed in registers, and the rest\n\
4245 on the stack. If a multi-word argument (a @code{double} or a\n\
4246 structure) crosses that boundary, its first few words must be passed\n\
4247 in registers and the rest must be pushed. This macro tells the\n\
4248 compiler when this occurs, and how many bytes should go in registers.\n\
4250 @code{TARGET_FUNCTION_ARG} for these arguments should return the first\n\
4251 register to be used by the caller for this argument; likewise\n\
4252 @code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.",
4253 int, (cumulative_args_t cum, machine_mode mode, tree type, bool named),
4254 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0)
4256 /* Update the state in CA to advance past an argument in the
4257 argument list. The values MODE, TYPE, and NAMED describe that
4258 argument. */
4259 DEFHOOK
4260 (function_arg_advance,
4261 "This hook updates the summarizer variable pointed to by @var{ca} to\n\
4262 advance past an argument in the argument list. The values @var{mode},\n\
4263 @var{type} and @var{named} describe that argument. Once this is done,\n\
4264 the variable @var{cum} is suitable for analyzing the @emph{following}\n\
4265 argument with @code{TARGET_FUNCTION_ARG}, etc.\n\
4267 This hook need not do anything if the argument in question was passed\n\
4268 on the stack. The compiler knows how to track the amount of stack space\n\
4269 used for arguments without any special help.",
4270 void,
4271 (cumulative_args_t ca, machine_mode mode, const_tree type, bool named),
4272 default_function_arg_advance)
4274 /* Return zero if the argument described by the state of CA should
4275 be placed on a stack, or a hard register in which to store the
4276 argument. The values MODE, TYPE, and NAMED describe that
4277 argument. */
4278 DEFHOOK
4279 (function_arg,
4280 "Return an RTX indicating whether a function argument is passed in a\n\
4281 register and if so, which register.\n\
4283 The arguments are @var{ca}, which summarizes all the previous\n\
4284 arguments; @var{mode}, the machine mode of the argument; @var{type},\n\
4285 the data type of the argument as a tree node or 0 if that is not known\n\
4286 (which happens for C support library functions); and @var{named},\n\
4287 which is @code{true} for an ordinary argument and @code{false} for\n\
4288 nameless arguments that correspond to @samp{@dots{}} in the called\n\
4289 function's prototype. @var{type} can be an incomplete type if a\n\
4290 syntax error has previously occurred.\n\
4292 The return value is usually either a @code{reg} RTX for the hard\n\
4293 register in which to pass the argument, or zero to pass the argument\n\
4294 on the stack.\n\
4296 The return value can be a @code{const_int} which means argument is\n\
4297 passed in a target specific slot with specified number. Target hooks\n\
4298 should be used to store or load argument in such case. See\n\
4299 @code{TARGET_STORE_BOUNDS_FOR_ARG} and @code{TARGET_LOAD_BOUNDS_FOR_ARG}\n\
4300 for more information.\n\
4302 The value of the expression can also be a @code{parallel} RTX@. This is\n\
4303 used when an argument is passed in multiple locations. The mode of the\n\
4304 @code{parallel} should be the mode of the entire argument. The\n\
4305 @code{parallel} holds any number of @code{expr_list} pairs; each one\n\
4306 describes where part of the argument is passed. In each\n\
4307 @code{expr_list} the first operand must be a @code{reg} RTX for the hard\n\
4308 register in which to pass this part of the argument, and the mode of the\n\
4309 register RTX indicates how large this part of the argument is. The\n\
4310 second operand of the @code{expr_list} is a @code{const_int} which gives\n\
4311 the offset in bytes into the entire argument of where this part starts.\n\
4312 As a special exception the first @code{expr_list} in the @code{parallel}\n\
4313 RTX may have a first operand of zero. This indicates that the entire\n\
4314 argument is also stored on the stack.\n\
4316 The last time this hook is called, it is called with @code{MODE ==\n\
4317 VOIDmode}, and its result is passed to the @code{call} or @code{call_value}\n\
4318 pattern as operands 2 and 3 respectively.\n\
4320 @cindex @file{stdarg.h} and register arguments\n\
4321 The usual way to make the ISO library @file{stdarg.h} work on a\n\
4322 machine where some arguments are usually passed in registers, is to\n\
4323 cause nameless arguments to be passed on the stack instead. This is\n\
4324 done by making @code{TARGET_FUNCTION_ARG} return 0 whenever\n\
4325 @var{named} is @code{false}.\n\
4327 @cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}\n\
4328 @cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}\n\
4329 You may use the hook @code{targetm.calls.must_pass_in_stack}\n\
4330 in the definition of this macro to determine if this argument is of a\n\
4331 type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}\n\
4332 is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an\n\
4333 argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is\n\
4334 defined, the argument will be computed in the stack and then loaded into\n\
4335 a register.",
4336 rtx, (cumulative_args_t ca, machine_mode mode, const_tree type,
4337 bool named),
4338 default_function_arg)
4340 /* Likewise, but for machines with register windows. Return the
4341 location where the argument will appear to the callee. */
4342 DEFHOOK
4343 (function_incoming_arg,
4344 "Define this hook if the target machine has ``register windows'', so\n\
4345 that the register in which a function sees an arguments is not\n\
4346 necessarily the same as the one in which the caller passed the\n\
4347 argument.\n\
4349 For such machines, @code{TARGET_FUNCTION_ARG} computes the register in\n\
4350 which the caller passes the value, and\n\
4351 @code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar\n\
4352 fashion to tell the function being called where the arguments will\n\
4353 arrive.\n\
4355 If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,\n\
4356 @code{TARGET_FUNCTION_ARG} serves both purposes.",
4357 rtx, (cumulative_args_t ca, machine_mode mode, const_tree type,
4358 bool named),
4359 default_function_incoming_arg)
4361 DEFHOOK
4362 (function_arg_boundary,
4363 "This hook returns the alignment boundary, in bits, of an argument\n\
4364 with the specified mode and type. The default hook returns\n\
4365 @code{PARM_BOUNDARY} for all arguments.",
4366 unsigned int, (machine_mode mode, const_tree type),
4367 default_function_arg_boundary)
4369 DEFHOOK
4370 (function_arg_round_boundary,
4371 "Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
4372 which is the default value for this hook. You can define this hook to\n\
4373 return a different value if an argument size must be rounded to a larger\n\
4374 value.",
4375 unsigned int, (machine_mode mode, const_tree type),
4376 default_function_arg_round_boundary)
4378 /* Return the diagnostic message string if function without a prototype
4379 is not allowed for this 'val' argument; NULL otherwise. */
4380 DEFHOOK
4381 (invalid_arg_for_unprototyped_fn,
4382 "If defined, this macro returns the diagnostic message when it is\n\
4383 illegal to pass argument @var{val} to function @var{funcdecl}\n\
4384 with prototype @var{typelist}.",
4385 const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
4386 hook_invalid_arg_for_unprototyped_fn)
4388 /* Return an rtx for the return value location of the function
4389 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
4390 DEFHOOK
4391 (function_value,
4392 "\n\
4393 Define this to return an RTX representing the place where a function\n\
4394 returns or receives a value of data type @var{ret_type}, a tree node\n\
4395 representing a data type. @var{fn_decl_or_type} is a tree node\n\
4396 representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a\n\
4397 function being called. If @var{outgoing} is false, the hook should\n\
4398 compute the register in which the caller will see the return value.\n\
4399 Otherwise, the hook should return an RTX representing the place where\n\
4400 a function returns a value.\n\
4402 On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.\n\
4403 (Actually, on most machines, scalar values are returned in the same\n\
4404 place regardless of mode.) The value of the expression is usually a\n\
4405 @code{reg} RTX for the hard register where the return value is stored.\n\
4406 The value can also be a @code{parallel} RTX, if the return value is in\n\
4407 multiple places. See @code{TARGET_FUNCTION_ARG} for an explanation of the\n\
4408 @code{parallel} form. Note that the callee will populate every\n\
4409 location specified in the @code{parallel}, but if the first element of\n\
4410 the @code{parallel} contains the whole return value, callers will use\n\
4411 that element as the canonical location and ignore the others. The m68k\n\
4412 port uses this type of @code{parallel} to return pointers in both\n\
4413 @samp{%a0} (the canonical location) and @samp{%d0}.\n\
4415 If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply\n\
4416 the same promotion rules specified in @code{PROMOTE_MODE} if\n\
4417 @var{valtype} is a scalar type.\n\
4419 If the precise function being called is known, @var{func} is a tree\n\
4420 node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null\n\
4421 pointer. This makes it possible to use a different value-returning\n\
4422 convention for specific functions when all their calls are\n\
4423 known.\n\
4425 Some target machines have ``register windows'' so that the register in\n\
4426 which a function returns its value is not the same as the one in which\n\
4427 the caller sees the value. For such machines, you should return\n\
4428 different RTX depending on @var{outgoing}.\n\
4430 @code{TARGET_FUNCTION_VALUE} is not used for return values with\n\
4431 aggregate data types, because these are returned in another way. See\n\
4432 @code{TARGET_STRUCT_VALUE_RTX} and related macros, below.",
4433 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
4434 default_function_value)
4436 /* Return the rtx for bounds of returned pointer. */
4437 DEFHOOK
4438 (chkp_function_value_bounds,
4439 "Define this to return an RTX representing the place where a function\n\
4440 returns bounds for returned pointers. Arguments meaning is similar to\n\
4441 @code{TARGET_FUNCTION_VALUE}.",
4442 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
4443 default_chkp_function_value_bounds)
4445 /* Return the rtx for the result of a libcall of mode MODE,
4446 calling the function FN_NAME. */
4447 DEFHOOK
4448 (libcall_value,
4449 "Define this hook if the back-end needs to know the name of the libcall\n\
4450 function in order to determine where the result should be returned.\n\
4452 The mode of the result is given by @var{mode} and the name of the called\n\
4453 library function is given by @var{fun}. The hook should return an RTX\n\
4454 representing the place where the library function result will be returned.\n\
4456 If this hook is not defined, then LIBCALL_VALUE will be used.",
4457 rtx, (machine_mode mode, const_rtx fun),
4458 default_libcall_value)
4460 /* Return true if REGNO is a possible register number for
4461 a function value as seen by the caller. */
4462 DEFHOOK
4463 (function_value_regno_p,
4464 "A target hook that return @code{true} if @var{regno} is the number of a hard\n\
4465 register in which the values of called function may come back.\n\
4467 A register whose use for returning values is limited to serving as the\n\
4468 second of a pair (for a value of type @code{double}, say) need not be\n\
4469 recognized by this target hook.\n\
4471 If the machine has register windows, so that the caller and the called\n\
4472 function use different registers for the return value, this target hook\n\
4473 should recognize only the caller's register numbers.\n\
4475 If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.",
4476 bool, (const unsigned int regno),
4477 default_function_value_regno_p)
4479 /* ??? Documenting this hook requires a GFDL license grant. */
4480 DEFHOOK_UNDOC
4481 (internal_arg_pointer,
4482 "Return an rtx for the argument pointer incoming to the\
4483 current function.",
4484 rtx, (void),
4485 default_internal_arg_pointer)
4487 /* Update the current function stack boundary if needed. */
4488 DEFHOOK
4489 (update_stack_boundary,
4490 "Define this macro to update the current function stack boundary if\n\
4491 necessary.",
4492 void, (void), NULL)
4494 /* Handle stack alignment and return an rtx for Dynamic Realign
4495 Argument Pointer if necessary. */
4496 DEFHOOK
4497 (get_drap_rtx,
4498 "This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a\n\
4499 different argument pointer register is needed to access the function's\n\
4500 argument list due to stack realignment. Return @code{NULL} if no DRAP\n\
4501 is needed.",
4502 rtx, (void), NULL)
4504 /* Return true if all function parameters should be spilled to the
4505 stack. */
4506 DEFHOOK
4507 (allocate_stack_slots_for_args,
4508 "When optimization is disabled, this hook indicates whether or not\n\
4509 arguments should be allocated to stack slots. Normally, GCC allocates\n\
4510 stacks slots for arguments when not optimizing in order to make\n\
4511 debugging easier. However, when a function is declared with\n\
4512 @code{__attribute__((naked))}, there is no stack frame, and the compiler\n\
4513 cannot safely move arguments from the registers in which they are passed\n\
4514 to the stack. Therefore, this hook should return true in general, but\n\
4515 false for naked functions. The default implementation always returns true.",
4516 bool, (void),
4517 hook_bool_void_true)
4519 /* Return an rtx for the static chain for FNDECL_OR_TYPE. If INCOMING_P
4520 is true, then it should be for the callee; otherwise for the caller. */
4521 DEFHOOK
4522 (static_chain,
4523 "This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for\n\
4524 targets that may use different static chain locations for different\n\
4525 nested functions. This may be required if the target has function\n\
4526 attributes that affect the calling conventions of the function and\n\
4527 those calling conventions use different static chain locations.\n\
4529 The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.\n\
4531 If the static chain is passed in memory, this hook should be used to\n\
4532 provide rtx giving @code{mem} expressions that denote where they are stored.\n\
4533 Often the @code{mem} expression as seen by the caller will be at an offset\n\
4534 from the stack pointer and the @code{mem} expression as seen by the callee\n\
4535 will be at an offset from the frame pointer.\n\
4536 @findex stack_pointer_rtx\n\
4537 @findex frame_pointer_rtx\n\
4538 @findex arg_pointer_rtx\n\
4539 The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and\n\
4540 @code{arg_pointer_rtx} will have been initialized and should be used\n\
4541 to refer to those items.",
4542 rtx, (const_tree fndecl_or_type, bool incoming_p),
4543 default_static_chain)
4545 /* Fill in the trampoline at MEM with a call to FNDECL and a
4546 static chain value of CHAIN. */
4547 DEFHOOK
4548 (trampoline_init,
4549 "This hook is called to initialize a trampoline.\n\
4550 @var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}\n\
4551 is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an\n\
4552 RTX for the static chain value that should be passed to the function\n\
4553 when it is called.\n\
4555 If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the\n\
4556 first thing this hook should do is emit a block move into @var{m_tramp}\n\
4557 from the memory block returned by @code{assemble_trampoline_template}.\n\
4558 Note that the block move need only cover the constant parts of the\n\
4559 trampoline. If the target isolates the variable parts of the trampoline\n\
4560 to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.\n\
4562 If the target requires any other actions, such as flushing caches or\n\
4563 enabling stack execution, these actions should be performed after\n\
4564 initializing the trampoline proper.",
4565 void, (rtx m_tramp, tree fndecl, rtx static_chain),
4566 default_trampoline_init)
4568 /* Adjust the address of the trampoline in a target-specific way. */
4569 DEFHOOK
4570 (trampoline_adjust_address,
4571 "This hook should perform any machine-specific adjustment in\n\
4572 the address of the trampoline. Its argument contains the address of the\n\
4573 memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}. In case\n\
4574 the address to be used for a function call should be different from the\n\
4575 address at which the template was stored, the different address should\n\
4576 be returned; otherwise @var{addr} should be returned unchanged.\n\
4577 If this hook is not defined, @var{addr} will be used for function calls.",
4578 rtx, (rtx addr), NULL)
4580 /* Return the number of bytes of its own arguments that a function
4581 pops on returning, or 0 if the function pops no arguments and the
4582 caller must therefore pop them all after the function returns. */
4583 /* ??? tm.texi has no types for the parameters. */
4584 DEFHOOK
4585 (return_pops_args,
4586 "This target hook returns the number of bytes of its own arguments that\n\
4587 a function pops on returning, or 0 if the function pops no arguments\n\
4588 and the caller must therefore pop them all after the function returns.\n\
4590 @var{fundecl} is a C variable whose value is a tree node that describes\n\
4591 the function in question. Normally it is a node of type\n\
4592 @code{FUNCTION_DECL} that describes the declaration of the function.\n\
4593 From this you can obtain the @code{DECL_ATTRIBUTES} of the function.\n\
4595 @var{funtype} is a C variable whose value is a tree node that\n\
4596 describes the function in question. Normally it is a node of type\n\
4597 @code{FUNCTION_TYPE} that describes the data type of the function.\n\
4598 From this it is possible to obtain the data types of the value and\n\
4599 arguments (if known).\n\
4601 When a call to a library function is being considered, @var{fundecl}\n\
4602 will contain an identifier node for the library function. Thus, if\n\
4603 you need to distinguish among various library functions, you can do so\n\
4604 by their names. Note that ``library function'' in this context means\n\
4605 a function used to perform arithmetic, whose name is known specially\n\
4606 in the compiler and was not mentioned in the C code being compiled.\n\
4608 @var{size} is the number of bytes of arguments passed on the\n\
4609 stack. If a variable number of bytes is passed, it is zero, and\n\
4610 argument popping will always be the responsibility of the calling function.\n\
4612 On the VAX, all functions always pop their arguments, so the definition\n\
4613 of this macro is @var{size}. On the 68000, using the standard\n\
4614 calling convention, no functions pop their arguments, so the value of\n\
4615 the macro is always 0 in this case. But an alternative calling\n\
4616 convention is available in which functions that take a fixed number of\n\
4617 arguments pop them but other functions (such as @code{printf}) pop\n\
4618 nothing (the caller pops all). When this convention is in use,\n\
4619 @var{funtype} is examined to determine whether a function takes a fixed\n\
4620 number of arguments.",
4621 int, (tree fundecl, tree funtype, int size),
4622 default_return_pops_args)
4624 /* Return a mode wide enough to copy any function value that might be
4625 returned. */
4626 DEFHOOK
4627 (get_raw_result_mode,
4628 "This target hook returns the mode to be used when accessing raw return\
4629 registers in @code{__builtin_return}. Define this macro if the value\
4630 in @var{reg_raw_mode} is not correct.",
4631 machine_mode, (int regno),
4632 default_get_reg_raw_mode)
4634 /* Return a mode wide enough to copy any argument value that might be
4635 passed. */
4636 DEFHOOK
4637 (get_raw_arg_mode,
4638 "This target hook returns the mode to be used when accessing raw argument\
4639 registers in @code{__builtin_apply_args}. Define this macro if the value\
4640 in @var{reg_raw_mode} is not correct.",
4641 machine_mode, (int regno),
4642 default_get_reg_raw_mode)
4644 HOOK_VECTOR_END (calls)
4646 DEFHOOK
4647 (use_pseudo_pic_reg,
4648 "This hook should return 1 in case pseudo register should be created\n\
4649 for pic_offset_table_rtx during function expand.",
4650 bool, (void),
4651 hook_bool_void_false)
4653 DEFHOOK
4654 (init_pic_reg,
4655 "Perform a target dependent initialization of pic_offset_table_rtx.\n\
4656 This hook is called at the start of register allocation.",
4657 void, (void),
4658 hook_void_void)
4660 /* Return the diagnostic message string if conversion from FROMTYPE
4661 to TOTYPE is not allowed, NULL otherwise. */
4662 DEFHOOK
4663 (invalid_conversion,
4664 "If defined, this macro returns the diagnostic message when it is\n\
4665 invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}\n\
4666 if validity should be determined by the front end.",
4667 const char *, (const_tree fromtype, const_tree totype),
4668 hook_constcharptr_const_tree_const_tree_null)
4670 /* Return the diagnostic message string if the unary operation OP is
4671 not permitted on TYPE, NULL otherwise. */
4672 DEFHOOK
4673 (invalid_unary_op,
4674 "If defined, this macro returns the diagnostic message when it is\n\
4675 invalid to apply operation @var{op} (where unary plus is denoted by\n\
4676 @code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}\n\
4677 if validity should be determined by the front end.",
4678 const char *, (int op, const_tree type),
4679 hook_constcharptr_int_const_tree_null)
4681 /* Return the diagnostic message string if the binary operation OP
4682 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
4683 DEFHOOK
4684 (invalid_binary_op,
4685 "If defined, this macro returns the diagnostic message when it is\n\
4686 invalid to apply operation @var{op} to operands of types @var{type1}\n\
4687 and @var{type2}, or @code{NULL} if validity should be determined by\n\
4688 the front end.",
4689 const char *, (int op, const_tree type1, const_tree type2),
4690 hook_constcharptr_int_const_tree_const_tree_null)
4692 /* Return the diagnostic message string if TYPE is not valid as a
4693 function parameter type, NULL otherwise. */
4694 DEFHOOK
4695 (invalid_parameter_type,
4696 "If defined, this macro returns the diagnostic message when it is\n\
4697 invalid for functions to include parameters of type @var{type},\n\
4698 or @code{NULL} if validity should be determined by\n\
4699 the front end. This is currently used only by the C and C++ front ends.",
4700 const char *, (const_tree type),
4701 hook_constcharptr_const_tree_null)
4703 /* Return the diagnostic message string if TYPE is not valid as a
4704 function return type, NULL otherwise. */
4705 DEFHOOK
4706 (invalid_return_type,
4707 "If defined, this macro returns the diagnostic message when it is\n\
4708 invalid for functions to have return type @var{type},\n\
4709 or @code{NULL} if validity should be determined by\n\
4710 the front end. This is currently used only by the C and C++ front ends.",
4711 const char *, (const_tree type),
4712 hook_constcharptr_const_tree_null)
4714 /* If values of TYPE are promoted to some other type when used in
4715 expressions (analogous to the integer promotions), return that type,
4716 or NULL_TREE otherwise. */
4717 DEFHOOK
4718 (promoted_type,
4719 "If defined, this target hook returns the type to which values of\n\
4720 @var{type} should be promoted when they appear in expressions,\n\
4721 analogous to the integer promotions, or @code{NULL_TREE} to use the\n\
4722 front end's normal promotion rules. This hook is useful when there are\n\
4723 target-specific types with special promotion rules.\n\
4724 This is currently used only by the C and C++ front ends.",
4725 tree, (const_tree type),
4726 hook_tree_const_tree_null)
4728 /* Convert EXPR to TYPE, if target-specific types with special conversion
4729 rules are involved. Return the converted expression, or NULL to apply
4730 the standard conversion rules. */
4731 DEFHOOK
4732 (convert_to_type,
4733 "If defined, this hook returns the result of converting @var{expr} to\n\
4734 @var{type}. It should return the converted expression,\n\
4735 or @code{NULL_TREE} to apply the front end's normal conversion rules.\n\
4736 This hook is useful when there are target-specific types with special\n\
4737 conversion rules.\n\
4738 This is currently used only by the C and C++ front ends.",
4739 tree, (tree type, tree expr),
4740 hook_tree_tree_tree_null)
4742 /* Return true if we use LRA instead of reload. */
4743 DEFHOOK
4744 (lra_p,
4745 "A target hook which returns true if we use LRA instead of reload pass.\
4746 It means that LRA was ported to the target.\
4748 The default version of this target hook returns always false.",
4749 bool, (void),
4750 default_lra_p)
4752 /* Return register priority of given hard regno for the current target. */
4753 DEFHOOK
4754 (register_priority,
4755 "A target hook which returns the register priority number to which the\
4756 register @var{hard_regno} belongs to. The bigger the number, the\
4757 more preferable the hard register usage (when all other conditions are\
4758 the same). This hook can be used to prefer some hard register over\
4759 others in LRA. For example, some x86-64 register usage needs\
4760 additional prefix which makes instructions longer. The hook can\
4761 return lower priority number for such registers make them less favorable\
4762 and as result making the generated code smaller.\
4764 The default version of this target hook returns always zero.",
4765 int, (int),
4766 default_register_priority)
4768 /* Return true if we need register usage leveling. */
4769 DEFHOOK
4770 (register_usage_leveling_p,
4771 "A target hook which returns true if we need register usage leveling.\
4772 That means if a few hard registers are equally good for the\
4773 assignment, we choose the least used hard register. The register\
4774 usage leveling may be profitable for some targets. Don't use the\
4775 usage leveling for targets with conditional execution or targets\
4776 with big register files as it hurts if-conversion and cross-jumping\
4777 optimizations.\
4779 The default version of this target hook returns always false.",
4780 bool, (void),
4781 default_register_usage_leveling_p)
4783 /* Return true if maximal address displacement can be different. */
4784 DEFHOOK
4785 (different_addr_displacement_p,
4786 "A target hook which returns true if an address with the same structure\
4787 can have different maximal legitimate displacement. For example, the\
4788 displacement can depend on memory mode or on operand combinations in\
4789 the insn.\
4791 The default version of this target hook returns always false.",
4792 bool, (void),
4793 default_different_addr_displacement_p)
4795 /* Determine class for spilling pseudos of given mode into registers
4796 instead of memory. */
4797 DEFHOOK
4798 (spill_class,
4799 "This hook defines a class of registers which could be used for spilling\
4800 pseudos of the given mode and class, or @code{NO_REGS} if only memory\
4801 should be used. Not defining this hook is equivalent to returning\
4802 @code{NO_REGS} for all inputs.",
4803 reg_class_t, (reg_class_t, machine_mode),
4804 NULL)
4806 DEFHOOK
4807 (cstore_mode,
4808 "This hook defines the machine mode to use for the boolean result of\
4809 conditional store patterns. The ICODE argument is the instruction code\
4810 for the cstore being performed. Not definiting this hook is the same\
4811 as accepting the mode encoded into operand 0 of the cstore expander\
4812 patterns.",
4813 machine_mode, (enum insn_code icode),
4814 default_cstore_mode)
4816 /* True if a structure, union or array with MODE containing FIELD should
4817 be accessed using BLKmode. */
4818 DEFHOOK
4819 (member_type_forces_blk,
4820 "Return true if a structure, union or array containing @var{field} should\n\
4821 be accessed using @code{BLKMODE}.\n\
4823 If @var{field} is the only field in the structure, @var{mode} is its\n\
4824 mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the\n\
4825 case where structures of one field would require the structure's mode to\n\
4826 retain the field's mode.\n\
4828 Normally, this is not needed.",
4829 bool, (const_tree field, machine_mode mode),
4830 default_member_type_forces_blk)
4832 /* Return the class for a secondary reload, and fill in extra information. */
4833 DEFHOOK
4834 (secondary_reload,
4835 "Many machines have some registers that cannot be copied directly to or\n\
4836 from memory or even from other types of registers. An example is the\n\
4837 @samp{MQ} register, which on most machines, can only be copied to or\n\
4838 from general registers, but not memory. Below, we shall be using the\n\
4839 term 'intermediate register' when a move operation cannot be performed\n\
4840 directly, but has to be done by copying the source into the intermediate\n\
4841 register first, and then copying the intermediate register to the\n\
4842 destination. An intermediate register always has the same mode as\n\
4843 source and destination. Since it holds the actual value being copied,\n\
4844 reload might apply optimizations to re-use an intermediate register\n\
4845 and eliding the copy from the source when it can determine that the\n\
4846 intermediate register still holds the required value.\n\
4848 Another kind of secondary reload is required on some machines which\n\
4849 allow copying all registers to and from memory, but require a scratch\n\
4850 register for stores to some memory locations (e.g., those with symbolic\n\
4851 address on the RT, and those with certain symbolic address on the SPARC\n\
4852 when compiling PIC)@. Scratch registers need not have the same mode\n\
4853 as the value being copied, and usually hold a different value than\n\
4854 that being copied. Special patterns in the md file are needed to\n\
4855 describe how the copy is performed with the help of the scratch register;\n\
4856 these patterns also describe the number, register class(es) and mode(s)\n\
4857 of the scratch register(s).\n\
4859 In some cases, both an intermediate and a scratch register are required.\n\
4861 For input reloads, this target hook is called with nonzero @var{in_p},\n\
4862 and @var{x} is an rtx that needs to be copied to a register of class\n\
4863 @var{reload_class} in @var{reload_mode}. For output reloads, this target\n\
4864 hook is called with zero @var{in_p}, and a register of class @var{reload_class}\n\
4865 needs to be copied to rtx @var{x} in @var{reload_mode}.\n\
4867 If copying a register of @var{reload_class} from/to @var{x} requires\n\
4868 an intermediate register, the hook @code{secondary_reload} should\n\
4869 return the register class required for this intermediate register.\n\
4870 If no intermediate register is required, it should return NO_REGS.\n\
4871 If more than one intermediate register is required, describe the one\n\
4872 that is closest in the copy chain to the reload register.\n\
4874 If scratch registers are needed, you also have to describe how to\n\
4875 perform the copy from/to the reload register to/from this\n\
4876 closest intermediate register. Or if no intermediate register is\n\
4877 required, but still a scratch register is needed, describe the\n\
4878 copy from/to the reload register to/from the reload operand @var{x}.\n\
4880 You do this by setting @code{sri->icode} to the instruction code of a pattern\n\
4881 in the md file which performs the move. Operands 0 and 1 are the output\n\
4882 and input of this copy, respectively. Operands from operand 2 onward are\n\
4883 for scratch operands. These scratch operands must have a mode, and a\n\
4884 single-register-class\n\
4885 @c [later: or memory]\n\
4886 output constraint.\n\
4888 When an intermediate register is used, the @code{secondary_reload}\n\
4889 hook will be called again to determine how to copy the intermediate\n\
4890 register to/from the reload operand @var{x}, so your hook must also\n\
4891 have code to handle the register class of the intermediate operand.\n\
4893 @c [For later: maybe we'll allow multi-alternative reload patterns -\n\
4894 @c the port maintainer could name a mov<mode> pattern that has clobbers -\n\
4895 @c and match the constraints of input and output to determine the required\n\
4896 @c alternative. A restriction would be that constraints used to match\n\
4897 @c against reloads registers would have to be written as register class\n\
4898 @c constraints, or we need a new target macro / hook that tells us if an\n\
4899 @c arbitrary constraint can match an unknown register of a given class.\n\
4900 @c Such a macro / hook would also be useful in other places.]\n\
4903 @var{x} might be a pseudo-register or a @code{subreg} of a\n\
4904 pseudo-register, which could either be in a hard register or in memory.\n\
4905 Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is\n\
4906 in memory and the hard register number if it is in a register.\n\
4908 Scratch operands in memory (constraint @code{\"=m\"} / @code{\"=&m\"}) are\n\
4909 currently not supported. For the time being, you will have to continue\n\
4910 to use @code{SECONDARY_MEMORY_NEEDED} for that purpose.\n\
4912 @code{copy_cost} also uses this target hook to find out how values are\n\
4913 copied. If you want it to include some extra cost for the need to allocate\n\
4914 (a) scratch register(s), set @code{sri->extra_cost} to the additional cost.\n\
4915 Or if two dependent moves are supposed to have a lower cost than the sum\n\
4916 of the individual moves due to expected fortuitous scheduling and/or special\n\
4917 forwarding logic, you can set @code{sri->extra_cost} to a negative amount.",
4918 reg_class_t,
4919 (bool in_p, rtx x, reg_class_t reload_class, machine_mode reload_mode,
4920 secondary_reload_info *sri),
4921 default_secondary_reload)
4923 /* Given an rtx X being reloaded into a reg required to be in class CLASS,
4924 return the class of reg to actually use. */
4925 DEFHOOK
4926 (preferred_reload_class,
4927 "A target hook that places additional restrictions on the register class\n\
4928 to use when it is necessary to copy value @var{x} into a register in class\n\
4929 @var{rclass}. The value is a register class; perhaps @var{rclass}, or perhaps\n\
4930 another, smaller class.\n\
4932 The default version of this hook always returns value of @code{rclass} argument.\n\
4934 Sometimes returning a more restrictive class makes better code. For\n\
4935 example, on the 68000, when @var{x} is an integer constant that is in range\n\
4936 for a @samp{moveq} instruction, the value of this macro is always\n\
4937 @code{DATA_REGS} as long as @var{rclass} includes the data registers.\n\
4938 Requiring a data register guarantees that a @samp{moveq} will be used.\n\
4940 One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return\n\
4941 @var{rclass} is if @var{x} is a legitimate constant which cannot be\n\
4942 loaded into some register class. By returning @code{NO_REGS} you can\n\
4943 force @var{x} into a memory location. For example, rs6000 can load\n\
4944 immediate values into general-purpose registers, but does not have an\n\
4945 instruction for loading an immediate value into a floating-point\n\
4946 register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when\n\
4947 @var{x} is a floating-point constant. If the constant can't be loaded\n\
4948 into any kind of register, code generation will be better if\n\
4949 @code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead\n\
4950 of using @code{TARGET_PREFERRED_RELOAD_CLASS}.\n\
4952 If an insn has pseudos in it after register allocation, reload will go\n\
4953 through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}\n\
4954 to find the best one. Returning @code{NO_REGS}, in this case, makes\n\
4955 reload add a @code{!} in front of the constraint: the x86 back-end uses\n\
4956 this feature to discourage usage of 387 registers when math is done in\n\
4957 the SSE registers (and vice versa).",
4958 reg_class_t,
4959 (rtx x, reg_class_t rclass),
4960 default_preferred_reload_class)
4962 /* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
4963 input reloads. */
4964 DEFHOOK
4965 (preferred_output_reload_class,
4966 "Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of\n\
4967 input reloads.\n\
4969 The default version of this hook always returns value of @code{rclass}\n\
4970 argument.\n\
4972 You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage\n\
4973 reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.",
4974 reg_class_t,
4975 (rtx x, reg_class_t rclass),
4976 default_preferred_output_reload_class)
4978 DEFHOOK
4979 (class_likely_spilled_p,
4980 "A target hook which returns @code{true} if pseudos that have been assigned\n\
4981 to registers of class @var{rclass} would likely be spilled because\n\
4982 registers of @var{rclass} are needed for spill registers.\n\
4984 The default version of this target hook returns @code{true} if @var{rclass}\n\
4985 has exactly one register and @code{false} otherwise. On most machines, this\n\
4986 default should be used. For generally register-starved machines, such as\n\
4987 i386, or machines with right register constraints, such as SH, this hook\n\
4988 can be used to avoid excessive spilling.\n\
4990 This hook is also used by some of the global intra-procedural code\n\
4991 transformations to throtle code motion, to avoid increasing register\n\
4992 pressure.",
4993 bool, (reg_class_t rclass),
4994 default_class_likely_spilled_p)
4996 /* Return the maximum number of consecutive registers
4997 needed to represent mode MODE in a register of class RCLASS. */
4998 DEFHOOK
4999 (class_max_nregs,
5000 "A target hook returns the maximum number of consecutive registers\n\
5001 of class @var{rclass} needed to hold a value of mode @var{mode}.\n\
5003 This is closely related to the macro @code{HARD_REGNO_NREGS}. In fact,\n\
5004 the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},\n\
5005 @var{mode})} target hook should be the maximum value of\n\
5006 @code{HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}\n\
5007 values in the class @var{rclass}.\n\
5009 This target hook helps control the handling of multiple-word values\n\
5010 in the reload pass.\n\
5012 The default version of this target hook returns the size of @var{mode}\n\
5013 in words.",
5014 unsigned char, (reg_class_t rclass, machine_mode mode),
5015 default_class_max_nregs)
5017 DEFHOOK
5018 (preferred_rename_class,
5019 "A target hook that places additional preference on the register\
5020 class to use when it is necessary to rename a register in class\
5021 @var{rclass} to another class, or perhaps @var{NO_REGS}, if no\
5022 preferred register class is found or hook @code{preferred_rename_class}\
5023 is not implemented.\
5024 Sometimes returning a more restrictive class makes better code. For\
5025 example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\
5026 smaller than instructions using @code{GENERIC_REGS}. By returning\
5027 @code{LO_REGS} from @code{preferred_rename_class}, code size can\
5028 be reduced.",
5029 reg_class_t, (reg_class_t rclass),
5030 default_preferred_rename_class)
5032 /* This target hook allows the backend to perform additional
5033 processing while initializing for variable expansion. */
5034 DEFHOOK
5035 (expand_to_rtl_hook,
5036 "This hook is called just before expansion into rtl, allowing the target\n\
5037 to perform additional initializations or analysis before the expansion.\n\
5038 For example, the rs6000 port uses it to allocate a scratch stack slot\n\
5039 for use in copying SDmode values between memory and floating point\n\
5040 registers whenever the function being expanded has any SDmode\n\
5041 usage.",
5042 void, (void),
5043 hook_void_void)
5045 /* This target hook allows the backend to perform additional
5046 instantiations on rtx that are not actually in insns yet,
5047 but will be later. */
5048 DEFHOOK
5049 (instantiate_decls,
5050 "This hook allows the backend to perform additional instantiations on rtl\n\
5051 that are not actually in any insns yet, but will be later.",
5052 void, (void),
5053 hook_void_void)
5055 /* Return true if is OK to use a hard register REGNO as scratch register
5056 in peephole2. */
5057 DEFHOOK
5058 (hard_regno_scratch_ok,
5059 "This target hook should return @code{true} if it is OK to use a hard register\n\
5060 @var{regno} as scratch reg in peephole2.\n\
5062 One common use of this macro is to prevent using of a register that\n\
5063 is not saved by a prologue in an interrupt handler.\n\
5065 The default version of this hook always returns @code{true}.",
5066 bool, (unsigned int regno),
5067 default_hard_regno_scratch_ok)
5069 /* Return the smallest number of different values for which it is best to
5070 use a jump-table instead of a tree of conditional branches. */
5071 DEFHOOK
5072 (case_values_threshold,
5073 "This function return the smallest number of different values for which it\n\
5074 is best to use a jump-table instead of a tree of conditional branches.\n\
5075 The default is four for machines with a @code{casesi} instruction and\n\
5076 five otherwise. This is best for most machines.",
5077 unsigned int, (void),
5078 default_case_values_threshold)
5080 /* Retutn true if a function must have and use a frame pointer. */
5081 DEFHOOK
5082 (frame_pointer_required,
5083 "This target hook should return @code{true} if a function must have and use\n\
5084 a frame pointer. This target hook is called in the reload pass. If its return\n\
5085 value is @code{true} the function will have a frame pointer.\n\
5087 This target hook can in principle examine the current function and decide\n\
5088 according to the facts, but on most machines the constant @code{false} or the\n\
5089 constant @code{true} suffices. Use @code{false} when the machine allows code\n\
5090 to be generated with no frame pointer, and doing so saves some time or space.\n\
5091 Use @code{true} when there is no possible advantage to avoiding a frame\n\
5092 pointer.\n\
5094 In certain cases, the compiler does not know how to produce valid code\n\
5095 without a frame pointer. The compiler recognizes those cases and\n\
5096 automatically gives the function a frame pointer regardless of what\n\
5097 @code{TARGET_FRAME_POINTER_REQUIRED} returns. You don't need to worry about\n\
5098 them.\n\
5100 In a function that does not require a frame pointer, the frame pointer\n\
5101 register can be allocated for ordinary usage, unless you mark it as a\n\
5102 fixed register. See @code{FIXED_REGISTERS} for more information.\n\
5104 Default return value is @code{false}.",
5105 bool, (void),
5106 hook_bool_void_false)
5108 /* Returns true if the compiler is allowed to try to replace register number
5109 from-reg with register number to-reg. */
5110 DEFHOOK
5111 (can_eliminate,
5112 "This target hook should returns @code{true} if the compiler is allowed to\n\
5113 try to replace register number @var{from_reg} with register number\n\
5114 @var{to_reg}. This target hook need only be defined if @code{ELIMINABLE_REGS}\n\
5115 is defined, and will usually be @code{true}, since most of the cases\n\
5116 preventing register elimination are things that the compiler already\n\
5117 knows about.\n\
5119 Default return value is @code{true}.",
5120 bool, (const int from_reg, const int to_reg),
5121 hook_bool_const_int_const_int_true)
5123 /* Modify any or all of fixed_regs, call_used_regs, global_regs,
5124 reg_names, and reg_class_contents to account of the vagaries of the
5125 target. */
5126 DEFHOOK
5127 (conditional_register_usage,
5128 "This hook may conditionally modify five variables\n\
5129 @code{fixed_regs}, @code{call_used_regs}, @code{global_regs},\n\
5130 @code{reg_names}, and @code{reg_class_contents}, to take into account\n\
5131 any dependence of these register sets on target flags. The first three\n\
5132 of these are of type @code{char []} (interpreted as Boolean vectors).\n\
5133 @code{global_regs} is a @code{const char *[]}, and\n\
5134 @code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is\n\
5135 called, @code{fixed_regs}, @code{call_used_regs},\n\
5136 @code{reg_class_contents}, and @code{reg_names} have been initialized\n\
5137 from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},\n\
5138 @code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.\n\
5139 @code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},\n\
5140 @option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}\n\
5141 command options have been applied.\n\
5143 @cindex disabling certain registers\n\
5144 @cindex controlling register usage\n\
5145 If the usage of an entire class of registers depends on the target\n\
5146 flags, you may indicate this to GCC by using this macro to modify\n\
5147 @code{fixed_regs} and @code{call_used_regs} to 1 for each of the\n\
5148 registers in the classes which should not be used by GCC@. Also make\n\
5149 @code{define_register_constraint}s return @code{NO_REGS} for constraints\n\
5150 that shouldn't be used.\n\
5152 (However, if this class is not included in @code{GENERAL_REGS} and all\n\
5153 of the insn patterns whose constraints permit this class are\n\
5154 controlled by target switches, then GCC will automatically avoid using\n\
5155 these registers when the target switches are opposed to them.)",
5156 void, (void),
5157 hook_void_void)
5159 /* Functions specific to the C family of frontends. */
5160 #undef HOOK_PREFIX
5161 #define HOOK_PREFIX "TARGET_C_"
5162 HOOK_VECTOR (TARGET_C, c)
5164 /* ??? Documenting this hook requires a GFDL license grant. */
5165 DEFHOOK_UNDOC
5166 (mode_for_suffix,
5167 "Return machine mode for non-standard constant literal suffix @var{c},\
5168 or VOIDmode if non-standard suffixes are unsupported.",
5169 machine_mode, (char c),
5170 default_mode_for_suffix)
5172 HOOK_VECTOR_END (c)
5174 /* Functions specific to the C++ frontend. */
5175 #undef HOOK_PREFIX
5176 #define HOOK_PREFIX "TARGET_CXX_"
5177 HOOK_VECTOR (TARGET_CXX, cxx)
5179 /* Return the integer type used for guard variables. */
5180 DEFHOOK
5181 (guard_type,
5182 "Define this hook to override the integer type used for guard variables.\n\
5183 These are used to implement one-time construction of static objects. The\n\
5184 default is long_long_integer_type_node.",
5185 tree, (void),
5186 default_cxx_guard_type)
5188 /* Return true if only the low bit of the guard should be tested. */
5189 DEFHOOK
5190 (guard_mask_bit,
5191 "This hook determines how guard variables are used. It should return\n\
5192 @code{false} (the default) if the first byte should be used. A return value of\n\
5193 @code{true} indicates that only the least significant bit should be used.",
5194 bool, (void),
5195 hook_bool_void_false)
5197 /* Returns the size of the array cookie for an array of type. */
5198 DEFHOOK
5199 (get_cookie_size,
5200 "This hook returns the size of the cookie to use when allocating an array\n\
5201 whose elements have the indicated @var{type}. Assumes that it is already\n\
5202 known that a cookie is needed. The default is\n\
5203 @code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the\n\
5204 IA64/Generic C++ ABI@.",
5205 tree, (tree type),
5206 default_cxx_get_cookie_size)
5208 /* Returns true if the element size should be stored in the array cookie. */
5209 DEFHOOK
5210 (cookie_has_size,
5211 "This hook should return @code{true} if the element size should be stored in\n\
5212 array cookies. The default is to return @code{false}.",
5213 bool, (void),
5214 hook_bool_void_false)
5216 /* Allows backends to perform additional processing when
5217 deciding if a class should be exported or imported. */
5218 DEFHOOK
5219 (import_export_class,
5220 "If defined by a backend this hook allows the decision made to export\n\
5221 class @var{type} to be overruled. Upon entry @var{import_export}\n\
5222 will contain 1 if the class is going to be exported, @minus{}1 if it is going\n\
5223 to be imported and 0 otherwise. This function should return the\n\
5224 modified value and perform any other actions necessary to support the\n\
5225 backend's targeted operating system.",
5226 int, (tree type, int import_export), NULL)
5228 /* Returns true if constructors and destructors return "this". */
5229 DEFHOOK
5230 (cdtor_returns_this,
5231 "This hook should return @code{true} if constructors and destructors return\n\
5232 the address of the object created/destroyed. The default is to return\n\
5233 @code{false}.",
5234 bool, (void),
5235 hook_bool_void_false)
5237 /* Returns true if the key method for a class can be an inline
5238 function, so long as it is not declared inline in the class
5239 itself. Returning true is the behavior required by the Itanium C++ ABI. */
5240 DEFHOOK
5241 (key_method_may_be_inline,
5242 "This hook returns true if the key method for a class (i.e., the method\n\
5243 which, if defined in the current translation unit, causes the virtual\n\
5244 table to be emitted) may be an inline function. Under the standard\n\
5245 Itanium C++ ABI the key method may be an inline function so long as\n\
5246 the function is not declared inline in the class definition. Under\n\
5247 some variants of the ABI, an inline function can never be the key\n\
5248 method. The default is to return @code{true}.",
5249 bool, (void),
5250 hook_bool_void_true)
5252 DEFHOOK
5253 (determine_class_data_visibility,
5254 "@var{decl} is a virtual table, virtual table table, typeinfo object,\
5255 or other similar implicit class data object that will be emitted with\
5256 external linkage in this translation unit. No ELF visibility has been\
5257 explicitly specified. If the target needs to specify a visibility\
5258 other than that of the containing class, use this hook to set\
5259 @code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
5260 void, (tree decl),
5261 hook_void_tree)
5263 /* Returns true (the default) if virtual tables and other
5264 similar implicit class data objects are always COMDAT if they
5265 have external linkage. If this hook returns false, then
5266 class data for classes whose virtual table will be emitted in
5267 only one translation unit will not be COMDAT. */
5268 DEFHOOK
5269 (class_data_always_comdat,
5270 "This hook returns true (the default) if virtual tables and other\n\
5271 similar implicit class data objects are always COMDAT if they have\n\
5272 external linkage. If this hook returns false, then class data for\n\
5273 classes whose virtual table will be emitted in only one translation\n\
5274 unit will not be COMDAT.",
5275 bool, (void),
5276 hook_bool_void_true)
5278 /* Returns true (the default) if the RTTI for the basic types,
5279 which is always defined in the C++ runtime, should be COMDAT;
5280 false if it should not be COMDAT. */
5281 DEFHOOK
5282 (library_rtti_comdat,
5283 "This hook returns true (the default) if the RTTI information for\n\
5284 the basic types which is defined in the C++ runtime should always\n\
5285 be COMDAT, false if it should not be COMDAT.",
5286 bool, (void),
5287 hook_bool_void_true)
5289 /* Returns true if __aeabi_atexit should be used to register static
5290 destructors. */
5291 DEFHOOK
5292 (use_aeabi_atexit,
5293 "This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)\n\
5294 should be used to register static destructors when @option{-fuse-cxa-atexit}\n\
5295 is in effect. The default is to return false to use @code{__cxa_atexit}.",
5296 bool, (void),
5297 hook_bool_void_false)
5299 /* Returns true if target may use atexit in the same manner as
5300 __cxa_atexit to register static destructors. */
5301 DEFHOOK
5302 (use_atexit_for_cxa_atexit,
5303 "This hook returns true if the target @code{atexit} function can be used\n\
5304 in the same manner as @code{__cxa_atexit} to register C++ static\n\
5305 destructors. This requires that @code{atexit}-registered functions in\n\
5306 shared libraries are run in the correct order when the libraries are\n\
5307 unloaded. The default is to return false.",
5308 bool, (void),
5309 hook_bool_void_false)
5311 DEFHOOK
5312 (adjust_class_at_definition,
5313 "@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\
5314 been defined. Use this hook to make adjustments to the class (eg, tweak\
5315 visibility or perform any other required target modifications).",
5316 void, (tree type),
5317 hook_void_tree)
5319 DEFHOOK
5320 (decl_mangling_context,
5321 "Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
5322 tree, (const_tree decl),
5323 hook_tree_const_tree_null)
5325 HOOK_VECTOR_END (cxx)
5327 /* Functions and data for emulated TLS support. */
5328 #undef HOOK_PREFIX
5329 #define HOOK_PREFIX "TARGET_EMUTLS_"
5330 HOOK_VECTOR (TARGET_EMUTLS, emutls)
5332 /* Name of the address and common functions. */
5333 DEFHOOKPOD
5334 (get_address,
5335 "Contains the name of the helper function that uses a TLS control\n\
5336 object to locate a TLS instance. The default causes libgcc's\n\
5337 emulated TLS helper function to be used.",
5338 const char *, "__builtin___emutls_get_address")
5340 DEFHOOKPOD
5341 (register_common,
5342 "Contains the name of the helper function that should be used at\n\
5343 program startup to register TLS objects that are implicitly\n\
5344 initialized to zero. If this is @code{NULL}, all TLS objects will\n\
5345 have explicit initializers. The default causes libgcc's emulated TLS\n\
5346 registration function to be used.",
5347 const char *, "__builtin___emutls_register_common")
5349 /* Prefixes for proxy variable and template. */
5350 DEFHOOKPOD
5351 (var_section,
5352 "Contains the name of the section in which TLS control variables should\n\
5353 be placed. The default of @code{NULL} allows these to be placed in\n\
5354 any section.",
5355 const char *, NULL)
5357 DEFHOOKPOD
5358 (tmpl_section,
5359 "Contains the name of the section in which TLS initializers should be\n\
5360 placed. The default of @code{NULL} allows these to be placed in any\n\
5361 section.",
5362 const char *, NULL)
5364 /* Prefixes for proxy variable and template. */
5365 DEFHOOKPOD
5366 (var_prefix,
5367 "Contains the prefix to be prepended to TLS control variable names.\n\
5368 The default of @code{NULL} uses a target-specific prefix.",
5369 const char *, NULL)
5371 DEFHOOKPOD
5372 (tmpl_prefix,
5373 "Contains the prefix to be prepended to TLS initializer objects. The\n\
5374 default of @code{NULL} uses a target-specific prefix.",
5375 const char *, NULL)
5377 /* Function to generate field definitions of the proxy variable. */
5378 DEFHOOK
5379 (var_fields,
5380 "Specifies a function that generates the FIELD_DECLs for a TLS control\n\
5381 object type. @var{type} is the RECORD_TYPE the fields are for and\n\
5382 @var{name} should be filled with the structure tag, if the default of\n\
5383 @code{__emutls_object} is unsuitable. The default creates a type suitable\n\
5384 for libgcc's emulated TLS function.",
5385 tree, (tree type, tree *name),
5386 default_emutls_var_fields)
5388 /* Function to initialize a proxy variable. */
5389 DEFHOOK
5390 (var_init,
5391 "Specifies a function that generates the CONSTRUCTOR to initialize a\n\
5392 TLS control object. @var{var} is the TLS control object, @var{decl}\n\
5393 is the TLS object and @var{tmpl_addr} is the address of the\n\
5394 initializer. The default initializes libgcc's emulated TLS control object.",
5395 tree, (tree var, tree decl, tree tmpl_addr),
5396 default_emutls_var_init)
5398 /* Whether we are allowed to alter the usual alignment of the
5399 proxy variable. */
5400 DEFHOOKPOD
5401 (var_align_fixed,
5402 "Specifies whether the alignment of TLS control variable objects is\n\
5403 fixed and should not be increased as some backends may do to optimize\n\
5404 single objects. The default is false.",
5405 bool, false)
5407 /* Whether we can emit debug information for TLS vars. */
5408 DEFHOOKPOD
5409 (debug_form_tls_address,
5410 "Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor\n\
5411 may be used to describe emulated TLS control objects.",
5412 bool, false)
5414 HOOK_VECTOR_END (emutls)
5416 #undef HOOK_PREFIX
5417 #define HOOK_PREFIX "TARGET_OPTION_"
5418 HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)
5420 /* Function to validate the attribute((target(...))) strings. If
5421 the option is validated, the hook should also fill in
5422 DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
5423 DEFHOOK
5424 (valid_attribute_p,
5425 "This hook is called to parse @code{attribute(target(\"...\"))}, which\n\
5426 allows setting target-specific options on individual functions.\n\
5427 These function-specific options may differ\n\
5428 from the options specified on the command line. The hook should return\n\
5429 @code{true} if the options are valid.\n\
5431 The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
5432 the function declaration to hold a pointer to a target-specific\n\
5433 @code{struct cl_target_option} structure.",
5434 bool, (tree fndecl, tree name, tree args, int flags),
5435 default_target_option_valid_attribute_p)
5437 /* Function to save any extra target state in the target options structure. */
5438 DEFHOOK
5439 (save,
5440 "This hook is called to save any additional target-specific information\n\
5441 in the @code{struct cl_target_option} structure for function-specific\n\
5442 options from the @code{struct gcc_options} structure.\n\
5443 @xref{Option file format}.",
5444 void, (struct cl_target_option *ptr, struct gcc_options *opts), NULL)
5446 /* Function to restore any extra target state from the target options
5447 structure. */
5448 DEFHOOK
5449 (restore,
5450 "This hook is called to restore any additional target-specific\n\
5451 information in the @code{struct cl_target_option} structure for\n\
5452 function-specific options to the @code{struct gcc_options} structure.",
5453 void, (struct gcc_options *opts, struct cl_target_option *ptr), NULL)
5455 /* Function to print any extra target state from the target options
5456 structure. */
5457 DEFHOOK
5458 (print,
5459 "This hook is called to print any additional target-specific\n\
5460 information in the @code{struct cl_target_option} structure for\n\
5461 function-specific options.",
5462 void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)
5464 /* Function to parse arguments to be validated for #pragma target, and to
5465 change the state if the options are valid. If the first argument is
5466 NULL, the second argument specifies the default options to use. Return
5467 true if the options are valid, and set the current state. */
5468 DEFHOOK
5469 (pragma_parse,
5470 "This target hook parses the options for @code{#pragma GCC target}, which\n\
5471 sets the target-specific options for functions that occur later in the\n\
5472 input stream. The options accepted should be the same as those handled by the\n\
5473 @code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.",
5474 bool, (tree args, tree pop_target),
5475 default_target_option_pragma_parse)
5477 /* Do option overrides for the target. */
5478 DEFHOOK
5479 (override,
5480 "Sometimes certain combinations of command options do not make sense on\n\
5481 a particular target machine. You can override the hook\n\
5482 @code{TARGET_OPTION_OVERRIDE} to take account of this. This hooks is called\n\
5483 once just after all the command options have been parsed.\n\
5485 Don't use this hook to turn on various extra optimizations for\n\
5486 @option{-O}. That is what @code{TARGET_OPTION_OPTIMIZATION} is for.\n\
5488 If you need to do something whenever the optimization level is\n\
5489 changed via the optimize attribute or pragma, see\n\
5490 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}",
5491 void, (void),
5492 hook_void_void)
5494 /* This function returns true if DECL1 and DECL2 are versions of the same
5495 function. DECL1 and DECL2 are function versions if and only if they
5496 have the same function signature and different target specific attributes,
5497 that is, they are compiled for different target machines. */
5498 DEFHOOK
5499 (function_versions,
5500 "This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are\n\
5501 versions of the same function. @var{DECL1} and @var{DECL2} are function\n\
5502 versions if and only if they have the same function signature and\n\
5503 different target specific attributes, that is, they are compiled for\n\
5504 different target machines.",
5505 bool, (tree decl1, tree decl2),
5506 hook_bool_tree_tree_false)
5508 /* Function to determine if one function can inline another function. */
5509 #undef HOOK_PREFIX
5510 #define HOOK_PREFIX "TARGET_"
5511 DEFHOOK
5512 (can_inline_p,
5513 "This target hook returns @code{false} if the @var{caller} function\n\
5514 cannot inline @var{callee}, based on target specific information. By\n\
5515 default, inlining is not allowed if the callee function has function\n\
5516 specific target options and the caller does not use the same options.",
5517 bool, (tree caller, tree callee),
5518 default_target_can_inline_p)
5520 HOOK_VECTOR_END (target_option)
5522 /* For targets that need to mark extra registers as live on entry to
5523 the function, they should define this target hook and set their
5524 bits in the bitmap passed in. */
5525 DEFHOOK
5526 (extra_live_on_entry,
5527 "Add any hard registers to @var{regs} that are live on entry to the\n\
5528 function. This hook only needs to be defined to provide registers that\n\
5529 cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved\n\
5530 registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,\n\
5531 TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,\n\
5532 FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.",
5533 void, (bitmap regs),
5534 hook_void_bitmap)
5536 /* Targets should define this target hook to mark that non-callee clobbers are
5537 present in CALL_INSN_FUNCTION_USAGE for all the calls that bind to a local
5538 definition. */
5539 DEFHOOKPOD
5540 (call_fusage_contains_non_callee_clobbers,
5541 "Set to true if each call that binds to a local definition explicitly\n\
5542 clobbers or sets all non-fixed registers modified by performing the call.\n\
5543 That is, by the call pattern itself, or by code that might be inserted by the\n\
5544 linker (e.g. stubs, veneers, branch islands), but not including those\n\
5545 modifiable by the callee. The affected registers may be mentioned explicitly\n\
5546 in the call pattern, or included as clobbers in CALL_INSN_FUNCTION_USAGE.\n\
5547 The default version of this hook is set to false. The purpose of this hook\n\
5548 is to enable the fuse-caller-save optimization.",
5549 bool,
5550 false)
5552 /* Fill in additional registers set up by prologue into a regset. */
5553 DEFHOOK
5554 (set_up_by_prologue,
5555 "This hook should add additional registers that are computed by the prologue\
5556 to the hard regset for shrink-wrapping optimization purposes.",
5557 void, (struct hard_reg_set_container *),
5558 NULL)
5560 /* For targets that have attributes that can affect whether a
5561 function's return statements need checking. For instance a 'naked'
5562 function attribute. */
5563 DEFHOOK
5564 (warn_func_return,
5565 "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.",
5566 bool, (tree),
5567 hook_bool_tree_true)
5569 /* Determine the type of unwind info to emit for debugging. */
5570 DEFHOOK
5571 (debug_unwind_info,
5572 "This hook defines the mechanism that will be used for describing frame\n\
5573 unwind information to the debugger. Normally the hook will return\n\
5574 @code{UI_DWARF2} if DWARF 2 debug information is enabled, and\n\
5575 return @code{UI_NONE} otherwise.\n\
5577 A target may return @code{UI_DWARF2} even when DWARF 2 debug information\n\
5578 is disabled in order to always output DWARF 2 frame information.\n\
5580 A target may return @code{UI_TARGET} if it has ABI specified unwind tables.\n\
5581 This will suppress generation of the normal debug frame unwind information.",
5582 enum unwind_info_type, (void),
5583 default_debug_unwind_info)
5585 /* The code parameter should be of type enum rtx_code but this is not
5586 defined at this time. */
5587 DEFHOOK
5588 (canonicalize_comparison,
5589 "On some machines not all possible comparisons are defined, but you can\n\
5590 convert an invalid comparison into a valid one. For example, the Alpha\n\
5591 does not have a @code{GT} comparison, but you can use an @code{LT}\n\
5592 comparison instead and swap the order of the operands.\n\
5594 On such machines, implement this hook to do any required conversions.\n\
5595 @var{code} is the initial comparison code and @var{op0} and @var{op1}\n\
5596 are the left and right operands of the comparison, respectively. If\n\
5597 @var{op0_preserve_value} is @code{true} the implementation is not\n\
5598 allowed to change the value of @var{op0} since the value might be used\n\
5599 in RTXs which aren't comparisons. E.g. the implementation is not\n\
5600 allowed to swap operands in that case.\n\
5602 GCC will not assume that the comparison resulting from this macro is\n\
5603 valid but will see if the resulting insn matches a pattern in the\n\
5604 @file{md} file.\n\
5606 You need not to implement this hook if it would never change the\n\
5607 comparison code or operands.",
5608 void, (int *code, rtx *op0, rtx *op1, bool op0_preserve_value),
5609 default_canonicalize_comparison)
5611 DEFHOOKPOD
5612 (atomic_test_and_set_trueval,
5613 "This value should be set if the result written by\
5614 @code{atomic_test_and_set} is not exactly 1, i.e. the\
5615 @code{bool} @code{true}.",
5616 unsigned char, 1)
5618 /* Return an unsigned int representing the alignment (in bits) of the atomic
5619 type which maps to machine MODE. This allows alignment to be overridden
5620 as needed. */
5621 DEFHOOK
5622 (atomic_align_for_mode,
5623 "If defined, this function returns an appropriate alignment in bits for an\
5624 atomic object of machine_mode @var{mode}. If 0 is returned then the\
5625 default alignment for the specified mode is used. ",
5626 unsigned int, (machine_mode mode),
5627 hook_uint_mode_0)
5629 DEFHOOK
5630 (atomic_assign_expand_fenv,
5631 "ISO C11 requires atomic compound assignments that may raise floating-point\
5632 exceptions to raise exceptions corresponding to the arithmetic operation\
5633 whose result was successfully stored in a compare-and-exchange sequence. \
5634 This requires code equivalent to calls to @code{feholdexcept},\
5635 @code{feclearexcept} and @code{feupdateenv} to be generated at\
5636 appropriate points in the compare-and-exchange sequence. This hook should\
5637 set @code{*@var{hold}} to an expression equivalent to the call to\
5638 @code{feholdexcept}, @code{*@var{clear}} to an expression equivalent to\
5639 the call to @code{feclearexcept} and @code{*@var{update}} to an expression\
5640 equivalent to the call to @code{feupdateenv}. The three expressions are\
5641 @code{NULL_TREE} on entry to the hook and may be left as @code{NULL_TREE}\
5642 if no code is required in a particular place. The default implementation\
5643 leaves all three expressions as @code{NULL_TREE}. The\
5644 @code{__atomic_feraiseexcept} function from @code{libatomic} may be of use\
5645 as part of the code generated in @code{*@var{update}}.",
5646 void, (tree *hold, tree *clear, tree *update),
5647 default_atomic_assign_expand_fenv)
5649 /* Leave the boolean fields at the end. */
5651 /* True if we can create zeroed data by switching to a BSS section
5652 and then using ASM_OUTPUT_SKIP to allocate the space. */
5653 DEFHOOKPOD
5654 (have_switchable_bss_sections,
5655 "This flag is true if we can create zeroed data by switching to a BSS\n\
5656 section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.\n\
5657 This is true on most ELF targets.",
5658 bool, false)
5660 /* True if "native" constructors and destructors are supported,
5661 false if we're using collect2 for the job. */
5662 DEFHOOKPOD
5663 (have_ctors_dtors,
5664 "This value is true if the target supports some ``native'' method of\n\
5665 collecting constructors and destructors to be run at startup and exit.\n\
5666 It is false if we must use @command{collect2}.",
5667 bool, false)
5669 /* True if thread-local storage is supported. */
5670 DEFHOOKPOD
5671 (have_tls,
5672 "Contains the value true if the target supports thread-local storage.\n\
5673 The default value is false.",
5674 bool, false)
5676 /* True if a small readonly data section is supported. */
5677 DEFHOOKPOD
5678 (have_srodata_section,
5679 "Contains the value true if the target places read-only\n\
5680 ``small data'' into a separate section. The default value is false.",
5681 bool, false)
5683 /* True if EH frame info sections should be zero-terminated. */
5684 DEFHOOKPOD
5685 (terminate_dw2_eh_frame_info,
5686 "Contains the value true if the target should add a zero word onto the\n\
5687 end of a Dwarf-2 frame info section when used for exception handling.\n\
5688 Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and\n\
5689 true otherwise.",
5690 bool, true)
5692 /* True if #NO_APP should be emitted at the beginning of assembly output. */
5693 DEFHOOKPOD
5694 (asm_file_start_app_off,
5695 "If this flag is true, the text of the macro @code{ASM_APP_OFF} will be\n\
5696 printed as the very first line in the assembly file, unless\n\
5697 @option{-fverbose-asm} is in effect. (If that macro has been defined\n\
5698 to the empty string, this variable has no effect.) With the normal\n\
5699 definition of @code{ASM_APP_OFF}, the effect is to notify the GNU\n\
5700 assembler that it need not bother stripping comments or extra\n\
5701 whitespace from its input. This allows it to work a bit faster.\n\
5703 The default is false. You should not set it to true unless you have\n\
5704 verified that your port does not generate any extra whitespace or\n\
5705 comments that will cause GAS to issue errors in NO_APP mode.",
5706 bool, false)
5708 /* True if output_file_directive should be called for main_input_filename
5709 at the beginning of assembly output. */
5710 DEFHOOKPOD
5711 (asm_file_start_file_directive,
5712 "If this flag is true, @code{output_file_directive} will be called\n\
5713 for the primary source file, immediately after printing\n\
5714 @code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect\n\
5715 this to be done. The default is false.",
5716 bool, false)
5718 /* True if the target is allowed to reorder memory accesses unless
5719 synchronization is explicitly requested. */
5720 DEFHOOKPOD
5721 (relaxed_ordering,
5722 "If set to @code{true}, means that the target's memory model does not\n\
5723 guarantee that loads which do not depend on one another will access\n\
5724 main memory in the order of the instruction stream; if ordering is\n\
5725 important, an explicit memory barrier must be used. This is true of\n\
5726 many recent processors which implement a policy of ``relaxed,''\n\
5727 ``weak,'' or ``release'' memory consistency, such as Alpha, PowerPC,\n\
5728 and ia64. The default is @code{false}.",
5729 bool, false)
5731 /* Returns true if we should generate exception tables for use with the
5732 ARM EABI. The effects the encoding of function exception specifications. */
5733 DEFHOOKPOD
5734 (arm_eabi_unwinder,
5735 "This flag should be set to @code{true} on targets that use an ARM EABI\n\
5736 based unwinding library, and @code{false} on other targets. This effects\n\
5737 the format of unwinding tables, and how the unwinder in entered after\n\
5738 running a cleanup. The default is @code{false}.",
5739 bool, false)
5741 DEFHOOKPOD
5742 (want_debug_pub_sections,
5743 "True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\
5744 should be emitted. These sections are not used on most platforms, and\
5745 in particular GDB does not use them.",
5746 bool, false)
5748 DEFHOOKPOD
5749 (force_at_comp_dir,
5750 "True if the @code{DW_AT_comp_dir} attribute should be emitted for each \
5751 compilation unit. This attribute is required for the darwin linker \
5752 to emit debug information.",
5753 bool, false)
5755 DEFHOOKPOD
5756 (delay_sched2, "True if sched2 is not to be run at its normal place.\n\
5757 This usually means it will be run as part of machine-specific reorg.",
5758 bool, false)
5760 DEFHOOKPOD
5761 (delay_vartrack, "True if vartrack is not to be run at its normal place.\n\
5762 This usually means it will be run as part of machine-specific reorg.",
5763 bool, false)
5765 DEFHOOKPOD
5766 (no_register_allocation, "True if register allocation and the passes\n\
5767 following it should not be run. Usually true only for virtual assembler\n\
5768 targets.",
5769 bool, false)
5771 /* Leave the boolean fields at the end. */
5773 /* Functions related to mode switching. */
5774 #undef HOOK_PREFIX
5775 #define HOOK_PREFIX "TARGET_MODE_"
5776 HOOK_VECTOR (TARGET_TOGGLE_, mode_switching)
5778 DEFHOOK
5779 (emit,
5780 "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.",
5781 void, (int entity, int mode, int prev_mode, HARD_REG_SET regs_live), NULL)
5783 DEFHOOK
5784 (needed,
5785 "@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}.",
5786 int, (int entity, rtx_insn *insn), NULL)
5788 DEFHOOK
5789 (after,
5790 "@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).",
5791 int, (int entity, int mode, rtx_insn *insn), NULL)
5793 DEFHOOK
5794 (entry,
5795 "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.",
5796 int, (int entity), NULL)
5798 DEFHOOK
5799 (exit,
5800 "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.",
5801 int, (int entity), NULL)
5803 DEFHOOK
5804 (priority,
5805 "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}.",
5806 int, (int entity, int n), NULL)
5808 HOOK_VECTOR_END (mode_switching)
5810 /* Close the 'struct gcc_target' definition. */
5811 HOOK_VECTOR_END (C90_EMPTY_HACK)