re PR c++/58516 (ICE with __transaction_atomic)
[official-gcc.git] / gcc / target.def
blob6de513fdf9a627bd1c0ed96d411e6803f0e67d77
1 /* Target hook definitions.
2 Copyright (C) 2001-2013 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 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 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 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 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 /* Output code that will globalize a label. */
131 DEFHOOK
132 (globalize_label,
133 "This target hook is a function to output to the stdio stream\n\
134 @var{stream} some commands that will make the label @var{name} global;\n\
135 that is, available for reference from other files.\n\
137 The default implementation relies on a proper definition of\n\
138 @code{GLOBAL_ASM_OP}.",
139 void, (FILE *stream, const char *name),
140 default_globalize_label)
142 /* Output code that will globalize a declaration. */
143 DEFHOOK
144 (globalize_decl_name,
145 "This target hook is a function to output to the stdio stream\n\
146 @var{stream} some commands that will make the name associated with @var{decl}\n\
147 global; that is, available for reference from other files.\n\
149 The default implementation uses the TARGET_ASM_GLOBALIZE_LABEL target hook.",
150 void, (FILE *stream, tree decl), default_globalize_decl_name)
152 /* Output code that will emit a label for unwind info, if this
153 target requires such labels. Second argument is the decl the
154 unwind info is associated with, third is a boolean: true if
155 this is for exception handling, fourth is a boolean: true if
156 this is only a placeholder for an omitted FDE. */
157 DEFHOOK
158 (emit_unwind_label,
159 "This target hook emits a label at the beginning of each FDE@. It\n\
160 should be defined on targets where FDEs need special labels, and it\n\
161 should write the appropriate label, for the FDE associated with the\n\
162 function declaration @var{decl}, to the stdio stream @var{stream}.\n\
163 The third argument, @var{for_eh}, is a boolean: true if this is for an\n\
164 exception table. The fourth argument, @var{empty}, is a boolean:\n\
165 true if this is a placeholder label for an omitted FDE@.\n\
167 The default is that FDEs are not given nonlocal labels.",
168 void, (FILE *stream, tree decl, int for_eh, int empty),
169 default_emit_unwind_label)
171 /* Output code that will emit a label to divide up the exception table. */
172 DEFHOOK
173 (emit_except_table_label,
174 "This target hook emits a label at the beginning of the exception table.\n\
175 It should be defined on targets where it is desirable for the table\n\
176 to be broken up according to function.\n\
178 The default is that no label is emitted.",
179 void, (FILE *stream),
180 default_emit_except_table_label)
182 /* Emit a directive for setting the personality for the function. */
183 DEFHOOK
184 (emit_except_personality,
185 "If the target implements @code{TARGET_ASM_UNWIND_EMIT}, this hook may be\
186 used to emit a directive to install a personality hook into the unwind\
187 info. This hook should not be used if dwarf2 unwind info is used.",
188 void, (rtx personality),
189 NULL)
191 /* Emit any directives required to unwind this instruction. */
192 DEFHOOK
193 (unwind_emit,
194 "This target hook emits assembly directives required to unwind the\n\
195 given instruction. This is only used when @code{TARGET_EXCEPT_UNWIND_INFO}\n\
196 returns @code{UI_TARGET}.",
197 void, (FILE *stream, rtx insn),
198 NULL)
200 DEFHOOKPOD
201 (unwind_emit_before_insn,
202 "True if the @code{TARGET_ASM_UNWIND_EMIT} hook should be called before\
203 the assembly for @var{insn} has been emitted, false if the hook should\
204 be called afterward.",
205 bool, true)
207 /* Generate an internal label.
208 For now this is just a wrapper for ASM_GENERATE_INTERNAL_LABEL. */
209 DEFHOOK_UNDOC
210 (generate_internal_label,
212 void, (char *buf, const char *prefix, unsigned long labelno),
213 default_generate_internal_label)
215 /* Output an internal label. */
216 DEFHOOK
217 (internal_label,
218 "A function to output to the stdio stream @var{stream} a label whose\n\
219 name is made from the string @var{prefix} and the number @var{labelno}.\n\
221 It is absolutely essential that these labels be distinct from the labels\n\
222 used for user-level functions and variables. Otherwise, certain programs\n\
223 will have name conflicts with internal labels.\n\
225 It is desirable to exclude internal labels from the symbol table of the\n\
226 object file. Most assemblers have a naming convention for labels that\n\
227 should be excluded; on many systems, the letter @samp{L} at the\n\
228 beginning of a label has this effect. You should find out what\n\
229 convention your system uses, and follow it.\n\
231 The default version of this function utilizes @code{ASM_GENERATE_INTERNAL_LABEL}.",
232 void, (FILE *stream, const char *prefix, unsigned long labelno),
233 default_internal_label)
235 /* Output label for the constant. */
236 DEFHOOK
237 (declare_constant_name,
238 "A target hook to output to the stdio stream @var{file} any text necessary\n\
239 for declaring the name @var{name} of a constant which is being defined. This\n\
240 target hook is responsible for outputting the label definition (perhaps using\n\
241 @code{assemble_label}). The argument @var{exp} is the value of the constant,\n\
242 and @var{size} is the size of the constant in bytes. The @var{name}\n\
243 will be an internal label.\n\
245 The default version of this target hook, define the @var{name} in the\n\
246 usual manner as a label (by means of @code{assemble_label}).\n\
248 You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in this target hook.",
249 void, (FILE *file, const char *name, const_tree expr, HOST_WIDE_INT size),
250 default_asm_declare_constant_name)
252 /* Emit a ttype table reference to a typeinfo object. */
253 DEFHOOK
254 (ttype,
255 "This hook is used to output a reference from a frame unwinding table to\n\
256 the type_info object identified by @var{sym}. It should return @code{true}\n\
257 if the reference was output. Returning @code{false} will cause the\n\
258 reference to be output using the normal Dwarf2 routines.",
259 bool, (rtx sym),
260 hook_bool_rtx_false)
262 /* Emit an assembler directive to set visibility for the symbol
263 associated with the tree decl. */
264 DEFHOOK
265 (assemble_visibility,
266 "This target hook is a function to output to @var{asm_out_file} some\n\
267 commands that will make the symbol(s) associated with @var{decl} have\n\
268 hidden, protected or internal visibility as specified by @var{visibility}.",
269 void, (tree decl, int visibility),
270 default_assemble_visibility)
272 /* Output the assembler code for entry to a function. */
273 DEFHOOK
274 (function_prologue,
275 "If defined, a function that outputs the assembler code for entry to a\n\
276 function. The prologue is responsible for setting up the stack frame,\n\
277 initializing the frame pointer register, saving registers that must be\n\
278 saved, and allocating @var{size} additional bytes of storage for the\n\
279 local variables. @var{size} is an integer. @var{file} is a stdio\n\
280 stream to which the assembler code should be output.\n\
282 The label for the beginning of the function need not be output by this\n\
283 macro. That has already been done when the macro is run.\n\
285 @findex regs_ever_live\n\
286 To determine which registers to save, the macro can refer to the array\n\
287 @code{regs_ever_live}: element @var{r} is nonzero if hard register\n\
288 @var{r} is used anywhere within the function. This implies the function\n\
289 prologue should save register @var{r}, provided it is not one of the\n\
290 call-used registers. (@code{TARGET_ASM_FUNCTION_EPILOGUE} must likewise use\n\
291 @code{regs_ever_live}.)\n\
293 On machines that have ``register windows'', the function entry code does\n\
294 not save on the stack the registers that are in the windows, even if\n\
295 they are supposed to be preserved by function calls; instead it takes\n\
296 appropriate steps to ``push'' the register stack, if any non-call-used\n\
297 registers are used in the function.\n\
299 @findex frame_pointer_needed\n\
300 On machines where functions may or may not have frame-pointers, the\n\
301 function entry code must vary accordingly; it must set up the frame\n\
302 pointer if one is wanted, and not otherwise. To determine whether a\n\
303 frame pointer is in wanted, the macro can refer to the variable\n\
304 @code{frame_pointer_needed}. The variable's value will be 1 at run\n\
305 time in a function that needs a frame pointer. @xref{Elimination}.\n\
307 The function entry code is responsible for allocating any stack space\n\
308 required for the function. This stack space consists of the regions\n\
309 listed below. In most cases, these regions are allocated in the\n\
310 order listed, with the last listed region closest to the top of the\n\
311 stack (the lowest address if @code{STACK_GROWS_DOWNWARD} is defined, and\n\
312 the highest address if it is not defined). You can use a different order\n\
313 for a machine if doing so is more convenient or required for\n\
314 compatibility reasons. Except in cases where required by standard\n\
315 or by a debugger, there is no reason why the stack layout used by GCC\n\
316 need agree with that used by other compilers for a machine.",
317 void, (FILE *file, HOST_WIDE_INT size),
318 default_function_pro_epilogue)
320 /* Output the assembler code for end of prologue. */
321 DEFHOOK
322 (function_end_prologue,
323 "If defined, a function that outputs assembler code at the end of a\n\
324 prologue. This should be used when the function prologue is being\n\
325 emitted as RTL, and you have some extra assembler that needs to be\n\
326 emitted. @xref{prologue instruction pattern}.",
327 void, (FILE *file),
328 no_asm_to_stream)
330 /* Output the assembler code for start of epilogue. */
331 DEFHOOK
332 (function_begin_epilogue,
333 "If defined, a function that outputs assembler code at the start of an\n\
334 epilogue. This should be used when the function epilogue is being\n\
335 emitted as RTL, and you have some extra assembler that needs to be\n\
336 emitted. @xref{epilogue instruction pattern}.",
337 void, (FILE *file),
338 no_asm_to_stream)
340 /* Output the assembler code for function exit. */
341 DEFHOOK
342 (function_epilogue,
343 "If defined, a function that outputs the assembler code for exit from a\n\
344 function. The epilogue is responsible for restoring the saved\n\
345 registers and stack pointer to their values when the function was\n\
346 called, and returning control to the caller. This macro takes the\n\
347 same arguments as the macro @code{TARGET_ASM_FUNCTION_PROLOGUE}, and the\n\
348 registers to restore are determined from @code{regs_ever_live} and\n\
349 @code{CALL_USED_REGISTERS} in the same way.\n\
351 On some machines, there is a single instruction that does all the work\n\
352 of returning from the function. On these machines, give that\n\
353 instruction the name @samp{return} and do not define the macro\n\
354 @code{TARGET_ASM_FUNCTION_EPILOGUE} at all.\n\
356 Do not define a pattern named @samp{return} if you want the\n\
357 @code{TARGET_ASM_FUNCTION_EPILOGUE} to be used. If you want the target\n\
358 switches to control whether return instructions or epilogues are used,\n\
359 define a @samp{return} pattern with a validity condition that tests the\n\
360 target switches appropriately. If the @samp{return} pattern's validity\n\
361 condition is false, epilogues will be used.\n\
363 On machines where functions may or may not have frame-pointers, the\n\
364 function exit code must vary accordingly. Sometimes the code for these\n\
365 two cases is completely different. To determine whether a frame pointer\n\
366 is wanted, the macro can refer to the variable\n\
367 @code{frame_pointer_needed}. The variable's value will be 1 when compiling\n\
368 a function that needs a frame pointer.\n\
370 Normally, @code{TARGET_ASM_FUNCTION_PROLOGUE} and\n\
371 @code{TARGET_ASM_FUNCTION_EPILOGUE} must treat leaf functions specially.\n\
372 The C variable @code{current_function_is_leaf} is nonzero for such a\n\
373 function. @xref{Leaf Functions}.\n\
375 On some machines, some functions pop their arguments on exit while\n\
376 others leave that for the caller to do. For example, the 68020 when\n\
377 given @option{-mrtd} pops arguments in functions that take a fixed\n\
378 number of arguments.\n\
380 @findex pops_args\n\
381 @findex crtl->args.pops_args\n\
382 Your definition of the macro @code{RETURN_POPS_ARGS} decides which\n\
383 functions pop their own arguments. @code{TARGET_ASM_FUNCTION_EPILOGUE}\n\
384 needs to know what was decided. The number of bytes of the current\n\
385 function's arguments that this function should pop is available in\n\
386 @code{crtl->args.pops_args}. @xref{Scalar Return}.",
387 void, (FILE *file, HOST_WIDE_INT size),
388 default_function_pro_epilogue)
390 /* Initialize target-specific sections. */
391 DEFHOOK
392 (init_sections,
393 "Define this hook if you need to do something special to set up the\n\
394 @file{varasm.c} sections, or if your target has some special sections\n\
395 of its own that you need to create.\n\
397 GCC calls this hook after processing the command line, but before writing\n\
398 any assembly code, and before calling any of the section-returning hooks\n\
399 described below.",
400 void, (void),
401 hook_void_void)
403 /* Tell assembler to change to section NAME with attributes FLAGS.
404 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
405 which this section is associated. */
406 DEFHOOK
407 (named_section,
408 "Output assembly directives to switch to section @var{name}. The section\n\
409 should have attributes as specified by @var{flags}, which is a bit mask\n\
410 of the @code{SECTION_*} flags defined in @file{output.h}. If @var{decl}\n\
411 is non-NULL, it is the @code{VAR_DECL} or @code{FUNCTION_DECL} with which\n\
412 this section is associated.",
413 void, (const char *name, unsigned int flags, tree decl),
414 default_no_named_section)
416 /* Return preferred text (sub)section for function DECL.
417 Main purpose of this function is to separate cold, normal and hot
418 functions. STARTUP is true when function is known to be used only
419 at startup (from static constructors or it is main()).
420 EXIT is true when function is known to be used only at exit
421 (from static destructors).
422 Return NULL if function should go to default text section. */
423 DEFHOOK
424 (function_section,
425 "Return preferred text (sub)section for function @var{decl}.\n\
426 Main purpose of this function is to separate cold, normal and hot\n\
427 functions. @var{startup} is true when function is known to be used only\n\
428 at startup (from static constructors or it is @code{main()}).\n\
429 @var{exit} is true when function is known to be used only at exit\n\
430 (from static destructors).\n\
431 Return NULL if function should go to default text section.",
432 section *, (tree decl, enum node_frequency freq, bool startup, bool exit),
433 default_function_section)
435 /* Output the assembler code for function exit. */
436 DEFHOOK
437 (function_switched_text_sections,
438 "Used by the target to emit any assembler directives or additional\
439 labels needed when a function is partitioned between different\
440 sections. Output should be written to @var{file}. The function\
441 decl is available as @var{decl} and the new section is `cold' if\
442 @var{new_is_cold} is @code{true}.",
443 void, (FILE *file, tree decl, bool new_is_cold),
444 default_function_switched_text_sections)
446 /* Return a mask describing how relocations should be treated when
447 selecting sections. Bit 1 should be set if global relocations
448 should be placed in a read-write section; bit 0 should be set if
449 local relocations should be placed in a read-write section. */
450 DEFHOOK
451 (reloc_rw_mask,
452 "Return a mask describing how relocations should be treated when\n\
453 selecting sections. Bit 1 should be set if global relocations\n\
454 should be placed in a read-write section; bit 0 should be set if\n\
455 local relocations should be placed in a read-write section.\n\
457 The default version of this function returns 3 when @option{-fpic}\n\
458 is in effect, and 0 otherwise. The hook is typically redefined\n\
459 when the target cannot support (some kinds of) dynamic relocations\n\
460 in read-only sections even in executables.",
461 int, (void),
462 default_reloc_rw_mask)
464 /* Return a section for EXP. It may be a DECL or a constant. RELOC
465 is nonzero if runtime relocations must be applied; bit 1 will be
466 set if the runtime relocations require non-local name resolution.
467 ALIGN is the required alignment of the data. */
468 DEFHOOK
469 (select_section,
470 "Return the section into which @var{exp} should be placed. You can\n\
471 assume that @var{exp} is either a @code{VAR_DECL} node or a constant of\n\
472 some sort. @var{reloc} indicates whether the initial value of @var{exp}\n\
473 requires link-time relocations. Bit 0 is set when variable contains\n\
474 local relocations only, while bit 1 is set for global relocations.\n\
475 @var{align} is the constant alignment in bits.\n\
477 The default version of this function takes care of putting read-only\n\
478 variables in @code{readonly_data_section}.\n\
480 See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}.",
481 section *, (tree exp, int reloc, unsigned HOST_WIDE_INT align),
482 default_select_section)
484 /* Return a section for X. MODE is X's mode and ALIGN is its
485 alignment in bits. */
486 DEFHOOK
487 (select_rtx_section,
488 "Return the section into which a constant @var{x}, of mode @var{mode},\n\
489 should be placed. You can assume that @var{x} is some kind of\n\
490 constant in RTL@. The argument @var{mode} is redundant except in the\n\
491 case of a @code{const_int} rtx. @var{align} is the constant alignment\n\
492 in bits.\n\
494 The default version of this function takes care of putting symbolic\n\
495 constants in @code{flag_pic} mode in @code{data_section} and everything\n\
496 else in @code{readonly_data_section}.",
497 section *, (enum machine_mode mode, rtx x, unsigned HOST_WIDE_INT align),
498 default_select_rtx_section)
500 /* Select a unique section name for DECL. RELOC is the same as
501 for SELECT_SECTION. */
502 DEFHOOK
503 (unique_section,
504 "Build up a unique section name, expressed as a @code{STRING_CST} node,\n\
505 and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.\n\
506 As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether\n\
507 the initial value of @var{exp} requires link-time relocations.\n\
509 The default version of this function appends the symbol name to the\n\
510 ELF section name that would normally be used for the symbol. For\n\
511 example, the function @code{foo} would be placed in @code{.text.foo}.\n\
512 Whatever the actual target object format, this is often good enough.",
513 void, (tree decl, int reloc),
514 default_unique_section)
516 /* Return the readonly data section associated with function DECL. */
517 DEFHOOK
518 (function_rodata_section,
519 "Return the readonly data section associated with\n\
520 @samp{DECL_SECTION_NAME (@var{decl})}.\n\
521 The default version of this function selects @code{.gnu.linkonce.r.name} if\n\
522 the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name}\n\
523 if function is in @code{.text.name}, and the normal readonly-data section\n\
524 otherwise.",
525 section *, (tree decl),
526 default_function_rodata_section)
528 /* Nonnull if the target wants to override the default ".rodata" prefix
529 for mergeable data sections. */
530 DEFHOOKPOD
531 (mergeable_rodata_prefix,
532 "Usually, the compiler uses the prefix @code{\".rodata\"} to construct\n\
533 section names for mergeable constant data. Define this macro to override\n\
534 the string if a different section name should be used.",
535 const char *, ".rodata")
537 /* Return the section to be used for transactional memory clone tables. */
538 DEFHOOK
539 (tm_clone_table_section,
540 "Return the section that should be used for transactional memory clone\
541 tables.",
542 section *, (void), default_clone_table_section)
544 /* Output a constructor for a symbol with a given priority. */
545 DEFHOOK
546 (constructor,
547 "If defined, a function that outputs assembler code to arrange to call\n\
548 the function referenced by @var{symbol} at initialization time.\n\
550 Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking\n\
551 no arguments and with no return value. If the target supports initialization\n\
552 priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY};\n\
553 otherwise it must be @code{DEFAULT_INIT_PRIORITY}.\n\
555 If this macro is not defined by the target, a suitable default will\n\
556 be chosen if (1) the target supports arbitrary section names, (2) the\n\
557 target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2}\n\
558 is not defined.",
559 void, (rtx symbol, int priority), NULL)
561 /* Output a destructor for a symbol with a given priority. */
562 DEFHOOK
563 (destructor,
564 "This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination\n\
565 functions rather than initialization functions.",
566 void, (rtx symbol, int priority), NULL)
568 /* Output the assembler code for a thunk function. THUNK_DECL is the
569 declaration for the thunk function itself, FUNCTION is the decl for
570 the target function. DELTA is an immediate constant offset to be
571 added to THIS. If VCALL_OFFSET is nonzero, the word at
572 *(*this + vcall_offset) should be added to THIS. */
573 DEFHOOK
574 (output_mi_thunk,
575 "A function that outputs the assembler code for a thunk\n\
576 function, used to implement C++ virtual function calls with multiple\n\
577 inheritance. The thunk acts as a wrapper around a virtual function,\n\
578 adjusting the implicit object parameter before handing control off to\n\
579 the real function.\n\
581 First, emit code to add the integer @var{delta} to the location that\n\
582 contains the incoming first argument. Assume that this argument\n\
583 contains a pointer, and is the one used to pass the @code{this} pointer\n\
584 in C++. This is the incoming argument @emph{before} the function prologue,\n\
585 e.g.@: @samp{%o0} on a sparc. The addition must preserve the values of\n\
586 all other incoming arguments.\n\
588 Then, if @var{vcall_offset} is nonzero, an additional adjustment should be\n\
589 made after adding @code{delta}. In particular, if @var{p} is the\n\
590 adjusted pointer, the following adjustment should be made:\n\
592 @smallexample\n\
593 p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]\n\
594 @end smallexample\n\
596 After the additions, emit code to jump to @var{function}, which is a\n\
597 @code{FUNCTION_DECL}. This is a direct pure jump, not a call, and does\n\
598 not touch the return address. Hence returning from @var{FUNCTION} will\n\
599 return to whoever called the current @samp{thunk}.\n\
601 The effect must be as if @var{function} had been called directly with\n\
602 the adjusted first argument. This macro is responsible for emitting all\n\
603 of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE}\n\
604 and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked.\n\
606 The @var{thunk_fndecl} is redundant. (@var{delta} and @var{function}\n\
607 have already been extracted from it.) It might possibly be useful on\n\
608 some targets, but probably not.\n\
610 If you do not define this macro, the target-independent code in the C++\n\
611 front end will generate a less efficient heavyweight thunk that calls\n\
612 @var{function} instead of jumping to it. The generic approach does\n\
613 not support varargs.",
614 void, (FILE *file, tree thunk_fndecl, HOST_WIDE_INT delta,
615 HOST_WIDE_INT vcall_offset, tree function),
616 NULL)
618 /* Determine whether output_mi_thunk would succeed. */
619 /* ??? Ideally, this hook would not exist, and success or failure
620 would be returned from output_mi_thunk directly. But there's
621 too much undo-able setup involved in invoking output_mi_thunk.
622 Could be fixed by making output_mi_thunk emit rtl instead of
623 text to the output file. */
624 DEFHOOK
625 (can_output_mi_thunk,
626 "A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able\n\
627 to output the assembler code for the thunk function specified by the\n\
628 arguments it is passed, and false otherwise. In the latter case, the\n\
629 generic approach will be used by the C++ front end, with the limitations\n\
630 previously exposed.",
631 bool, (const_tree thunk_fndecl, HOST_WIDE_INT delta,
632 HOST_WIDE_INT vcall_offset, const_tree function),
633 hook_bool_const_tree_hwi_hwi_const_tree_false)
635 /* Output any boilerplate text needed at the beginning of a
636 translation unit. */
637 DEFHOOK
638 (file_start,
639 "Output to @code{asm_out_file} any text which the assembler expects to\n\
640 find at the beginning of a file. The default behavior is controlled\n\
641 by two flags, documented below. Unless your target's assembler is\n\
642 quite unusual, if you override the default, you should call\n\
643 @code{default_file_start} at some point in your target hook. This\n\
644 lets other target files rely on these variables.",
645 void, (void),
646 default_file_start)
648 /* Output any boilerplate text needed at the end of a translation unit. */
649 DEFHOOK
650 (file_end,
651 "Output to @code{asm_out_file} any text which the assembler expects\n\
652 to find at the end of a file. The default is to output nothing.",
653 void, (void),
654 hook_void_void)
656 /* Output any boilerplate text needed at the beginning of an
657 LTO output stream. */
658 DEFHOOK
659 (lto_start,
660 "Output to @code{asm_out_file} any text which the assembler expects\n\
661 to find at the start of an LTO section. The default is to output\n\
662 nothing.",
663 void, (void),
664 hook_void_void)
666 /* Output any boilerplate text needed at the end of an
667 LTO output stream. */
668 DEFHOOK
669 (lto_end,
670 "Output to @code{asm_out_file} any text which the assembler expects\n\
671 to find at the end of an LTO section. The default is to output\n\
672 nothing.",
673 void, (void),
674 hook_void_void)
676 /* Output any boilerplace text needed at the end of a
677 translation unit before debug and unwind info is emitted. */
678 DEFHOOK
679 (code_end,
680 "Output to @code{asm_out_file} any text which is needed before emitting\n\
681 unwind info and debug info at the end of a file. Some targets emit\n\
682 here PIC setup thunks that cannot be emitted at the end of file,\n\
683 because they couldn't have unwind info then. The default is to output\n\
684 nothing.",
685 void, (void),
686 hook_void_void)
688 /* Output an assembler pseudo-op to declare a library function name
689 external. */
690 DEFHOOK
691 (external_libcall,
692 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
693 pseudo-op to declare a library function name external. The name of the\n\
694 library function is given by @var{symref}, which is a @code{symbol_ref}.",
695 void, (rtx symref),
696 default_external_libcall)
698 /* Output an assembler directive to mark decl live. This instructs
699 linker to not dead code strip this symbol. */
700 DEFHOOK
701 (mark_decl_preserved,
702 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
703 directive to annotate @var{symbol} as used. The Darwin target uses the\n\
704 .no_dead_code_strip directive.",
705 void, (const char *symbol),
706 hook_void_constcharptr)
708 /* Output a record of the command line switches that have been passed. */
709 DEFHOOK
710 (record_gcc_switches,
711 "Provides the target with the ability to record the gcc command line\n\
712 switches that have been passed to the compiler, and options that are\n\
713 enabled. The @var{type} argument specifies what is being recorded.\n\
714 It can take the following values:\n\
716 @table @gcctabopt\n\
717 @item SWITCH_TYPE_PASSED\n\
718 @var{text} is a command line switch that has been set by the user.\n\
720 @item SWITCH_TYPE_ENABLED\n\
721 @var{text} is an option which has been enabled. This might be as a\n\
722 direct result of a command line switch, or because it is enabled by\n\
723 default or because it has been enabled as a side effect of a different\n\
724 command line switch. For example, the @option{-O2} switch enables\n\
725 various different individual optimization passes.\n\
727 @item SWITCH_TYPE_DESCRIPTIVE\n\
728 @var{text} is either NULL or some descriptive text which should be\n\
729 ignored. If @var{text} is NULL then it is being used to warn the\n\
730 target hook that either recording is starting or ending. The first\n\
731 time @var{type} is SWITCH_TYPE_DESCRIPTIVE and @var{text} is NULL, the\n\
732 warning is for start up and the second time the warning is for\n\
733 wind down. This feature is to allow the target hook to make any\n\
734 necessary preparations before it starts to record switches and to\n\
735 perform any necessary tidying up after it has finished recording\n\
736 switches.\n\
738 @item SWITCH_TYPE_LINE_START\n\
739 This option can be ignored by this target hook.\n\
741 @item SWITCH_TYPE_LINE_END\n\
742 This option can be ignored by this target hook.\n\
743 @end table\n\
745 The hook's return value must be zero. Other return values may be\n\
746 supported in the future.\n\
748 By default this hook is set to NULL, but an example implementation is\n\
749 provided for ELF based targets. Called @var{elf_record_gcc_switches},\n\
750 it records the switches as ASCII text inside a new, string mergeable\n\
751 section in the assembler output file. The name of the new section is\n\
752 provided by the @code{TARGET_ASM_RECORD_GCC_SWITCHES_SECTION} target\n\
753 hook.",
754 int, (print_switch_type type, const char *text),
755 NULL)
757 /* The name of the section that the example ELF implementation of
758 record_gcc_switches will use to store the information. Target
759 specific versions of record_gcc_switches may or may not use
760 this information. */
761 DEFHOOKPOD
762 (record_gcc_switches_section,
763 "This is the name of the section that will be created by the example\n\
764 ELF implementation of the @code{TARGET_ASM_RECORD_GCC_SWITCHES} target\n\
765 hook.",
766 const char *, ".GCC.command.line")
768 /* Output the definition of a section anchor. */
769 DEFHOOK
770 (output_anchor,
771 "Write the assembly code to define section anchor @var{x}, which is a\n\
772 @code{SYMBOL_REF} for which @samp{SYMBOL_REF_ANCHOR_P (@var{x})} is true.\n\
773 The hook is called with the assembly output position set to the beginning\n\
774 of @code{SYMBOL_REF_BLOCK (@var{x})}.\n\
776 If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses\n\
777 it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}.\n\
778 If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition\n\
779 is @code{NULL}, which disables the use of section anchors altogether.",
780 void, (rtx x),
781 default_asm_output_anchor)
783 DEFHOOK
784 (output_ident,
785 "Output a string based on @var{name}, suitable for the @samp{#ident} \
786 directive, or the equivalent directive or pragma in non-C-family languages. \
787 If this hook is not defined, nothing is output for the @samp{#ident} \
788 directive.",
789 void, (const char *name),
790 hook_void_constcharptr)
792 /* Output a DTP-relative reference to a TLS symbol. */
793 DEFHOOK
794 (output_dwarf_dtprel,
795 "If defined, this target hook is a function which outputs a DTP-relative\n\
796 reference to the given TLS symbol of the specified size.",
797 void, (FILE *file, int size, rtx x),
798 NULL)
800 /* Some target machines need to postscan each insn after it is output. */
801 DEFHOOK
802 (final_postscan_insn,
803 "If defined, this target hook is a function which is executed just after the\n\
804 output of assembler code for @var{insn}, to change the mode of the assembler\n\
805 if necessary.\n\
807 Here the argument @var{opvec} is the vector containing the operands\n\
808 extracted from @var{insn}, and @var{noperands} is the number of\n\
809 elements of the vector which contain meaningful data for this insn.\n\
810 The contents of this vector are what was used to convert the insn\n\
811 template into assembler code, so you can change the assembler mode\n\
812 by checking the contents of the vector.",
813 void, (FILE *file, rtx insn, rtx *opvec, int noperands),
814 NULL)
816 /* Emit the trampoline template. This hook may be NULL. */
817 DEFHOOK
818 (trampoline_template,
819 "This hook is called by @code{assemble_trampoline_template} to output,\n\
820 on the stream @var{f}, assembler code for a block of data that contains\n\
821 the constant parts of a trampoline. This code should not include a\n\
822 label---the label is taken care of automatically.\n\
824 If you do not define this hook, it means no template is needed\n\
825 for the target. Do not define this hook on systems where the block move\n\
826 code to copy the trampoline into place would be larger than the code\n\
827 to generate it on the spot.",
828 void, (FILE *f),
829 NULL)
831 DEFHOOK
832 (output_source_filename,
833 "Output COFF information or DWARF debugging information which indicates\
834 that filename @var{name} is the current source file to the stdio\
835 stream @var{file}.\n\
837 This target hook need not be defined if the standard form of output\
838 for the file format in use is appropriate.",
839 void ,(FILE *file, const char *name),
840 default_asm_output_source_filename)
842 DEFHOOK
843 (output_addr_const_extra,
844 "A target hook to recognize @var{rtx} patterns that @code{output_addr_const}\n\
845 can't deal with, and output assembly code to @var{file} corresponding to\n\
846 the pattern @var{x}. This may be used to allow machine-dependent\n\
847 @code{UNSPEC}s to appear within constants.\n\
849 If target hook fails to recognize a pattern, it must return @code{false},\n\
850 so that a standard error message is printed. If it prints an error message\n\
851 itself, by calling, for example, @code{output_operand_lossage}, it may just\n\
852 return @code{true}.",
853 bool, (FILE *file, rtx x),
854 hook_bool_FILEptr_rtx_false)
856 /* ??? The TARGET_PRINT_OPERAND* hooks are part of the asm_out struct,
857 even though that is not reflected in the macro name to override their
858 initializers. */
859 #undef HOOK_PREFIX
860 #define HOOK_PREFIX "TARGET_"
862 /* Emit a machine-specific insn operand. */
863 /* ??? tm.texi only documents the old macro PRINT_OPERAND,
864 not this hook, and uses a different name for the argument FILE. */
865 DEFHOOK_UNDOC
866 (print_operand,
868 void, (FILE *file, rtx x, int code),
869 default_print_operand)
871 /* Emit a machine-specific memory address. */
872 /* ??? tm.texi only documents the old macro PRINT_OPERAND_ADDRESS,
873 not this hook, and uses different argument names. */
874 DEFHOOK_UNDOC
875 (print_operand_address,
877 void, (FILE *file, rtx addr),
878 default_print_operand_address)
880 /* Determine whether CODE is a valid punctuation character for the
881 `print_operand' hook. */
882 /* ??? tm.texi only documents the old macro PRINT_OPERAND_PUNCT_VALID_P,
883 not this hook. */
884 DEFHOOK_UNDOC
885 (print_operand_punct_valid_p,
887 bool ,(unsigned char code),
888 default_print_operand_punct_valid_p)
890 /* Given a symbol name, perform same mangling as assemble_name and
891 ASM_OUTPUT_LABELREF, returning result as an IDENTIFIER_NODE. */
892 DEFHOOK
893 (mangle_assembler_name,
894 "Given a symbol @var{name}, perform same mangling as @code{varasm.c}'s\
895 @code{assemble_name}, but in memory rather than to a file stream, returning\
896 result as an @code{IDENTIFIER_NODE}. Required for correct LTO symtabs. The\
897 default implementation calls the @code{TARGET_STRIP_NAME_ENCODING} hook and\
898 then prepends the @code{USER_LABEL_PREFIX}, if any.",
899 tree, (const char *name),
900 default_mangle_assembler_name)
902 HOOK_VECTOR_END (asm_out)
904 /* Functions relating to instruction scheduling. All of these
905 default to null pointers, which haifa-sched.c looks for and handles. */
906 #undef HOOK_PREFIX
907 #define HOOK_PREFIX "TARGET_SCHED_"
908 HOOK_VECTOR (TARGET_SCHED, sched)
910 /* Given the current cost, COST, of an insn, INSN, calculate and
911 return a new cost based on its relationship to DEP_INSN through
912 the dependence LINK. The default is to make no adjustment. */
913 DEFHOOK
914 (adjust_cost,
915 "This function corrects the value of @var{cost} based on the\n\
916 relationship between @var{insn} and @var{dep_insn} through the\n\
917 dependence @var{link}. It should return the new value. The default\n\
918 is to make no adjustment to @var{cost}. This can be used for example\n\
919 to specify to the scheduler using the traditional pipeline description\n\
920 that an output- or anti-dependence does not incur the same cost as a\n\
921 data-dependence. If the scheduler using the automaton based pipeline\n\
922 description, the cost of anti-dependence is zero and the cost of\n\
923 output-dependence is maximum of one and the difference of latency\n\
924 times of the first and the second insns. If these values are not\n\
925 acceptable, you could use the hook to modify them too. See also\n\
926 @pxref{Processor pipeline description}.",
927 int, (rtx insn, rtx link, rtx dep_insn, int cost), NULL)
929 /* Adjust the priority of an insn as you see fit. Returns the new priority. */
930 DEFHOOK
931 (adjust_priority,
932 "This hook adjusts the integer scheduling priority @var{priority} of\n\
933 @var{insn}. It should return the new priority. Increase the priority to\n\
934 execute @var{insn} earlier, reduce the priority to execute @var{insn}\n\
935 later. Do not define this hook if you do not need to adjust the\n\
936 scheduling priorities of insns.",
937 int, (rtx insn, int priority), NULL)
939 /* Function which returns the maximum number of insns that can be
940 scheduled in the same machine cycle. This must be constant
941 over an entire compilation. The default is 1. */
942 DEFHOOK
943 (issue_rate,
944 "This hook returns the maximum number of instructions that can ever\n\
945 issue at the same time on the target machine. The default is one.\n\
946 Although the insn scheduler can define itself the possibility of issue\n\
947 an insn on the same cycle, the value can serve as an additional\n\
948 constraint to issue insns on the same simulated processor cycle (see\n\
949 hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).\n\
950 This value must be constant over the entire compilation. If you need\n\
951 it to vary depending on what the instructions are, you must use\n\
952 @samp{TARGET_SCHED_VARIABLE_ISSUE}.",
953 int, (void), NULL)
955 /* Calculate how much this insn affects how many more insns we
956 can emit this cycle. Default is they all cost the same. */
957 DEFHOOK
958 (variable_issue,
959 "This hook is executed by the scheduler after it has scheduled an insn\n\
960 from the ready list. It should return the number of insns which can\n\
961 still be issued in the current cycle. The default is\n\
962 @samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and\n\
963 @code{USE}, which normally are not counted against the issue rate.\n\
964 You should define this hook if some insns take more machine resources\n\
965 than others, so that fewer insns can follow them in the same cycle.\n\
966 @var{file} is either a null pointer, or a stdio stream to write any\n\
967 debug output to. @var{verbose} is the verbose level provided by\n\
968 @option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that\n\
969 was scheduled.",
970 int, (FILE *file, int verbose, rtx insn, int more), NULL)
972 /* Initialize machine-dependent scheduling code. */
973 DEFHOOK
974 (init,
975 "This hook is executed by the scheduler at the beginning of each block of\n\
976 instructions that are to be scheduled. @var{file} is either a null\n\
977 pointer, or a stdio stream to write any debug output to. @var{verbose}\n\
978 is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
979 @var{max_ready} is the maximum number of insns in the current scheduling\n\
980 region that can be live at the same time. This can be used to allocate\n\
981 scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}.",
982 void, (FILE *file, int verbose, int max_ready), NULL)
984 /* Finalize machine-dependent scheduling code. */
985 DEFHOOK
986 (finish,
987 "This hook is executed by the scheduler at the end of each block of\n\
988 instructions that are to be scheduled. It can be used to perform\n\
989 cleanup of any actions done by the other scheduling hooks. @var{file}\n\
990 is either a null pointer, or a stdio stream to write any debug output\n\
991 to. @var{verbose} is the verbose level provided by\n\
992 @option{-fsched-verbose-@var{n}}.",
993 void, (FILE *file, int verbose), NULL)
995 /* Initialize machine-dependent function wide scheduling code. */
996 DEFHOOK
997 (init_global,
998 "This hook is executed by the scheduler after function level initializations.\n\
999 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1000 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1001 @var{old_max_uid} is the maximum insn uid when scheduling begins.",
1002 void, (FILE *file, int verbose, int old_max_uid), NULL)
1004 /* Finalize machine-dependent function wide scheduling code. */
1005 DEFHOOK
1006 (finish_global,
1007 "This is the cleanup hook corresponding to @code{TARGET_SCHED_INIT_GLOBAL}.\n\
1008 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1009 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.",
1010 void, (FILE *file, int verbose), NULL)
1012 /* Reorder insns in a machine-dependent fashion, in two different
1013 places. Default does nothing. */
1014 DEFHOOK
1015 (reorder,
1016 "This hook is executed by the scheduler after it has scheduled the ready\n\
1017 list, to allow the machine description to reorder it (for example to\n\
1018 combine two small instructions together on @samp{VLIW} machines).\n\
1019 @var{file} is either a null pointer, or a stdio stream to write any\n\
1020 debug output to. @var{verbose} is the verbose level provided by\n\
1021 @option{-fsched-verbose-@var{n}}. @var{ready} is a pointer to the ready\n\
1022 list of instructions that are ready to be scheduled. @var{n_readyp} is\n\
1023 a pointer to the number of elements in the ready list. The scheduler\n\
1024 reads the ready list in reverse order, starting with\n\
1025 @var{ready}[@var{*n_readyp} @minus{} 1] and going to @var{ready}[0]. @var{clock}\n\
1026 is the timer tick of the scheduler. You may modify the ready list and\n\
1027 the number of ready insns. The return value is the number of insns that\n\
1028 can issue this cycle; normally this is just @code{issue_rate}. See also\n\
1029 @samp{TARGET_SCHED_REORDER2}.",
1030 int, (FILE *file, int verbose, rtx *ready, int *n_readyp, int clock), NULL)
1032 DEFHOOK
1033 (reorder2,
1034 "Like @samp{TARGET_SCHED_REORDER}, but called at a different time. That\n\
1035 function is called whenever the scheduler starts a new cycle. This one\n\
1036 is called once per iteration over a cycle, immediately after\n\
1037 @samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and\n\
1038 return the number of insns to be scheduled in the same cycle. Defining\n\
1039 this hook can be useful if there are frequent situations where\n\
1040 scheduling one insn causes other insns to become ready in the same\n\
1041 cycle. These other insns can then be taken into account properly.",
1042 int, (FILE *file, int verbose, rtx *ready, int *n_readyp, int clock), NULL)
1044 /* The following member value is a pointer to a function called
1045 after evaluation forward dependencies of insns in chain given
1046 by two parameter values (head and tail correspondingly). */
1047 DEFHOOK
1048 (dependencies_evaluation_hook,
1049 "This hook is called after evaluation forward dependencies of insns in\n\
1050 chain given by two parameter values (@var{head} and @var{tail}\n\
1051 correspondingly) but before insns scheduling of the insn chain. For\n\
1052 example, it can be used for better insn classification if it requires\n\
1053 analysis of dependencies. This hook can use backward and forward\n\
1054 dependencies of the insn scheduler because they are already\n\
1055 calculated.",
1056 void, (rtx head, rtx tail), NULL)
1058 /* The values of the following four members are pointers to functions
1059 used to simplify the automaton descriptions. dfa_pre_cycle_insn and
1060 dfa_post_cycle_insn give functions returning insns which are used to
1061 change the pipeline hazard recognizer state when the new simulated
1062 processor cycle correspondingly starts and finishes. The function
1063 defined by init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are
1064 used to initialize the corresponding insns. The default values of
1065 the members result in not changing the automaton state when the
1066 new simulated processor cycle correspondingly starts and finishes. */
1068 DEFHOOK
1069 (init_dfa_pre_cycle_insn,
1070 "The hook can be used to initialize data used by the previous hook.",
1071 void, (void), NULL)
1073 DEFHOOK
1074 (dfa_pre_cycle_insn,
1075 "The hook returns an RTL insn. The automaton state used in the\n\
1076 pipeline hazard recognizer is changed as if the insn were scheduled\n\
1077 when the new simulated processor cycle starts. Usage of the hook may\n\
1078 simplify the automaton pipeline description for some @acronym{VLIW}\n\
1079 processors. If the hook is defined, it is used only for the automaton\n\
1080 based pipeline description. The default is not to change the state\n\
1081 when the new simulated processor cycle starts.",
1082 rtx, (void), NULL)
1084 DEFHOOK
1085 (init_dfa_post_cycle_insn,
1086 "The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but\n\
1087 used to initialize data used by the previous hook.",
1088 void, (void), NULL)
1090 DEFHOOK
1091 (dfa_post_cycle_insn,
1092 "The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1093 to changed the state as if the insn were scheduled when the new\n\
1094 simulated processor cycle finishes.",
1095 rtx, (void), NULL)
1097 /* The values of the following two members are pointers to
1098 functions used to simplify the automaton descriptions.
1099 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
1100 immediately before and after cycle is advanced. */
1102 DEFHOOK
1103 (dfa_pre_advance_cycle,
1104 "The hook to notify target that the current simulated cycle is about to finish.\n\
1105 The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1106 to change the state in more complicated situations - e.g., when advancing\n\
1107 state on a single insn is not enough.",
1108 void, (void), NULL)
1110 DEFHOOK
1111 (dfa_post_advance_cycle,
1112 "The hook to notify target that new simulated cycle has just started.\n\
1113 The hook is analogous to @samp{TARGET_SCHED_DFA_POST_CYCLE_INSN} but used\n\
1114 to change the state in more complicated situations - e.g., when advancing\n\
1115 state on a single insn is not enough.",
1116 void, (void), NULL)
1118 /* The following member value is a pointer to a function returning value
1119 which defines how many insns in queue `ready' will we try for
1120 multi-pass scheduling. If the member value is nonzero and the
1121 function returns positive value, the DFA based scheduler will make
1122 multi-pass scheduling for the first cycle. In other words, we will
1123 try to choose ready insn which permits to start maximum number of
1124 insns on the same cycle. */
1125 DEFHOOK
1126 (first_cycle_multipass_dfa_lookahead,
1127 "This hook controls better choosing an insn from the ready insn queue\n\
1128 for the @acronym{DFA}-based insn scheduler. Usually the scheduler\n\
1129 chooses the first insn from the queue. If the hook returns a positive\n\
1130 value, an additional scheduler code tries all permutations of\n\
1131 @samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}\n\
1132 subsequent ready insns to choose an insn whose issue will result in\n\
1133 maximal number of issued insns on the same cycle. For the\n\
1134 @acronym{VLIW} processor, the code could actually solve the problem of\n\
1135 packing simple insns into the @acronym{VLIW} insn. Of course, if the\n\
1136 rules of @acronym{VLIW} packing are described in the automaton.\n\
1138 This code also could be used for superscalar @acronym{RISC}\n\
1139 processors. Let us consider a superscalar @acronym{RISC} processor\n\
1140 with 3 pipelines. Some insns can be executed in pipelines @var{A} or\n\
1141 @var{B}, some insns can be executed only in pipelines @var{B} or\n\
1142 @var{C}, and one insn can be executed in pipeline @var{B}. The\n\
1143 processor may issue the 1st insn into @var{A} and the 2nd one into\n\
1144 @var{B}. In this case, the 3rd insn will wait for freeing @var{B}\n\
1145 until the next cycle. If the scheduler issues the 3rd insn the first,\n\
1146 the processor could issue all 3 insns per cycle.\n\
1148 Actually this code demonstrates advantages of the automaton based\n\
1149 pipeline hazard recognizer. We try quickly and easy many insn\n\
1150 schedules to choose the best one.\n\
1152 The default is no multipass scheduling.",
1153 int, (void), NULL)
1155 /* The following member value is pointer to a function controlling
1156 what insns from the ready insn queue will be considered for the
1157 multipass insn scheduling. If the hook returns zero for insn
1158 passed as the parameter, the insn will be not chosen to be issued. */
1159 DEFHOOK
1160 (first_cycle_multipass_dfa_lookahead_guard,
1161 "\n\
1162 This hook controls what insns from the ready insn queue will be\n\
1163 considered for the multipass insn scheduling. If the hook returns\n\
1164 zero for @var{insn}, the insn will be not chosen to\n\
1165 be issued.\n\
1167 The default is that any ready insns can be chosen to be issued.",
1168 int, (rtx insn), NULL)
1170 /* This hook prepares the target for a new round of multipass
1171 scheduling.
1172 DATA is a pointer to target-specific data used for multipass scheduling.
1173 READY_TRY and N_READY represent the current state of search in the
1174 optimization space. The target can filter out instructions that
1175 should not be tried during current round by setting corresponding
1176 elements in READY_TRY to non-zero.
1177 FIRST_CYCLE_INSN_P is true if this is the first round of multipass
1178 scheduling on current cycle. */
1179 DEFHOOK
1180 (first_cycle_multipass_begin,
1181 "This hook prepares the target backend for a new round of multipass\n\
1182 scheduling.",
1183 void, (void *data, char *ready_try, int n_ready, bool first_cycle_insn_p),
1184 NULL)
1186 /* This hook is called when multipass scheduling evaluates instruction INSN.
1187 DATA is a pointer to target-specific data that can be used to record effects
1188 of INSN on CPU that are not described in DFA.
1189 READY_TRY and N_READY represent the current state of search in the
1190 optimization space. The target can filter out instructions that
1191 should not be tried after issuing INSN by setting corresponding
1192 elements in READY_TRY to non-zero.
1193 INSN is the instruction being evaluated.
1194 PREV_DATA is a pointer to target-specific data corresponding
1195 to a state before issuing INSN. */
1196 DEFHOOK
1197 (first_cycle_multipass_issue,
1198 "This hook is called when multipass scheduling evaluates instruction INSN.",
1199 void, (void *data, char *ready_try, int n_ready, rtx insn,
1200 const void *prev_data), NULL)
1202 /* This hook is called when multipass scheduling backtracks from evaluation of
1203 instruction corresponding to DATA.
1204 DATA is a pointer to target-specific data that stores the effects
1205 of instruction from which the algorithm backtracks on CPU that are not
1206 described in DFA.
1207 READY_TRY and N_READY represent the current state of search in the
1208 optimization space. The target can filter out instructions that
1209 should not be tried after issuing INSN by setting corresponding
1210 elements in READY_TRY to non-zero. */
1211 DEFHOOK
1212 (first_cycle_multipass_backtrack,
1213 "This is called when multipass scheduling backtracks from evaluation of\n\
1214 an instruction.",
1215 void, (const void *data, char *ready_try, int n_ready), NULL)
1217 /* This hook notifies the target about the result of the concluded current
1218 round of multipass scheduling.
1219 DATA is a pointer.
1220 If DATA is non-NULL it points to target-specific data used for multipass
1221 scheduling which corresponds to instruction at the start of the chain of
1222 the winning solution. DATA is NULL when multipass scheduling cannot find
1223 a good enough solution on current cycle and decides to retry later,
1224 usually after advancing the cycle count. */
1225 DEFHOOK
1226 (first_cycle_multipass_end,
1227 "This hook notifies the target about the result of the concluded current\n\
1228 round of multipass scheduling.",
1229 void, (const void *data), NULL)
1231 /* This hook is called to initialize target-specific data for multipass
1232 scheduling after it has been allocated.
1233 DATA is a pointer to target-specific data that stores the effects
1234 of instruction from which the algorithm backtracks on CPU that are not
1235 described in DFA. */
1236 DEFHOOK
1237 (first_cycle_multipass_init,
1238 "This hook initializes target-specific data used in multipass scheduling.",
1239 void, (void *data), NULL)
1241 /* This hook is called to finalize target-specific data for multipass
1242 scheduling before it is deallocated.
1243 DATA is a pointer to target-specific data that stores the effects
1244 of instruction from which the algorithm backtracks on CPU that are not
1245 described in DFA. */
1246 DEFHOOK
1247 (first_cycle_multipass_fini,
1248 "This hook finalizes target-specific data used in multipass scheduling.",
1249 void, (void *data), NULL)
1251 /* The following member value is pointer to a function called by
1252 the insn scheduler before issuing insn passed as the third
1253 parameter on given cycle. If the hook returns nonzero, the
1254 insn is not issued on given processors cycle. Instead of that,
1255 the processor cycle is advanced. If the value passed through
1256 the last parameter is zero, the insn ready queue is not sorted
1257 on the new cycle start as usually. The first parameter passes
1258 file for debugging output. The second one passes the scheduler
1259 verbose level of the debugging output. The forth and the fifth
1260 parameter values are correspondingly processor cycle on which
1261 the previous insn has been issued and the current processor cycle. */
1262 DEFHOOK
1263 (dfa_new_cycle,
1264 "This hook is called by the insn scheduler before issuing @var{insn}\n\
1265 on cycle @var{clock}. If the hook returns nonzero,\n\
1266 @var{insn} is not issued on this processor cycle. Instead,\n\
1267 the processor cycle is advanced. If *@var{sort_p}\n\
1268 is zero, the insn ready queue is not sorted on the new cycle\n\
1269 start as usually. @var{dump} and @var{verbose} specify the file and\n\
1270 verbosity level to use for debugging output.\n\
1271 @var{last_clock} and @var{clock} are, respectively, the\n\
1272 processor cycle on which the previous insn has been issued,\n\
1273 and the current processor cycle.",
1274 int, (FILE *dump, int verbose, rtx insn, int last_clock,
1275 int clock, int *sort_p),
1276 NULL)
1278 /* The following member value is a pointer to a function called by the
1279 insn scheduler. It should return true if there exists a dependence
1280 which is considered costly by the target, between the insn
1281 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
1282 the dep that represents the dependence between the two insns. The
1283 second argument is the cost of the dependence as estimated by
1284 the scheduler. The last argument is the distance in cycles
1285 between the already scheduled insn (first parameter) and the
1286 second insn (second parameter). */
1287 DEFHOOK
1288 (is_costly_dependence,
1289 "This hook is used to define which dependences are considered costly by\n\
1290 the target, so costly that it is not advisable to schedule the insns that\n\
1291 are involved in the dependence too close to one another. The parameters\n\
1292 to this hook are as follows: The first parameter @var{_dep} is the dependence\n\
1293 being evaluated. The second parameter @var{cost} is the cost of the\n\
1294 dependence as estimated by the scheduler, and the third\n\
1295 parameter @var{distance} is the distance in cycles between the two insns.\n\
1296 The hook returns @code{true} if considering the distance between the two\n\
1297 insns the dependence between them is considered costly by the target,\n\
1298 and @code{false} otherwise.\n\
1300 Defining this hook can be useful in multiple-issue out-of-order machines,\n\
1301 where (a) it's practically hopeless to predict the actual data/resource\n\
1302 delays, however: (b) there's a better chance to predict the actual grouping\n\
1303 that will be formed, and (c) correctly emulating the grouping can be very\n\
1304 important. In such targets one may want to allow issuing dependent insns\n\
1305 closer to one another---i.e., closer than the dependence distance; however,\n\
1306 not in cases of ``costly dependences'', which this hooks allows to define.",
1307 bool, (struct _dep *_dep, int cost, int distance), NULL)
1309 DEFHOOK_UNDOC
1310 (adjust_cost_2,
1311 "Given the current cost, @var{cost}, of an insn, @var{insn}, calculate and\
1312 return a new cost based on its relationship to @var{dep_insn} through the\
1313 dependence of weakness @var{dw}. The default is to make no adjustment.",
1314 int, (rtx insn, int dep_type1, rtx dep_insn, int cost, unsigned int dw), NULL)
1316 /* The following member value is a pointer to a function called
1317 by the insn scheduler. This hook is called to notify the backend
1318 that new instructions were emitted. */
1319 DEFHOOK
1320 (h_i_d_extended,
1321 "This hook is called by the insn scheduler after emitting a new instruction to\n\
1322 the instruction stream. The hook notifies a target backend to extend its\n\
1323 per instruction data structures.",
1324 void, (void), NULL)
1326 /* Next 5 functions are for multi-point scheduling. */
1328 /* Allocate memory for scheduler context. */
1329 DEFHOOK
1330 (alloc_sched_context,
1331 "Return a pointer to a store large enough to hold target scheduling context.",
1332 void *, (void), NULL)
1334 /* Fills the context from the local machine scheduler context. */
1335 DEFHOOK
1336 (init_sched_context,
1337 "Initialize store pointed to by @var{tc} to hold target scheduling context.\n\
1338 It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the\n\
1339 beginning of the block. Otherwise, copy the current context into @var{tc}.",
1340 void, (void *tc, bool clean_p), NULL)
1342 /* Sets local machine scheduler context to a saved value. */
1343 DEFHOOK
1344 (set_sched_context,
1345 "Copy target scheduling context pointed to by @var{tc} to the current context.",
1346 void, (void *tc), NULL)
1348 /* Clears a scheduler context so it becomes like after init. */
1349 DEFHOOK
1350 (clear_sched_context,
1351 "Deallocate internal data in target scheduling context pointed to by @var{tc}.",
1352 void, (void *tc), NULL)
1354 /* Frees the scheduler context. */
1355 DEFHOOK
1356 (free_sched_context,
1357 "Deallocate a store for target scheduling context pointed to by @var{tc}.",
1358 void, (void *tc), NULL)
1360 /* The following member value is a pointer to a function called
1361 by the insn scheduler.
1362 The first parameter is an instruction, the second parameter is the type
1363 of the requested speculation, and the third parameter is a pointer to the
1364 speculative pattern of the corresponding type (set if return value == 1).
1365 It should return
1366 -1, if there is no pattern, that will satisfy the requested speculation type,
1367 0, if current pattern satisfies the requested speculation type,
1368 1, if pattern of the instruction should be changed to the newly
1369 generated one. */
1370 DEFHOOK
1371 (speculate_insn,
1372 "This hook is called by the insn scheduler when @var{insn} has only\n\
1373 speculative dependencies and therefore can be scheduled speculatively.\n\
1374 The hook is used to check if the pattern of @var{insn} has a speculative\n\
1375 version and, in case of successful check, to generate that speculative\n\
1376 pattern. The hook should return 1, if the instruction has a speculative form,\n\
1377 or @minus{}1, if it doesn't. @var{request} describes the type of requested\n\
1378 speculation. If the return value equals 1 then @var{new_pat} is assigned\n\
1379 the generated speculative pattern.",
1380 int, (rtx insn, unsigned int dep_status, rtx *new_pat), NULL)
1382 /* The following member value is a pointer to a function called
1383 by the insn scheduler. It should return true if the check instruction
1384 passed as the parameter needs a recovery block. */
1385 DEFHOOK
1386 (needs_block_p,
1387 "This hook is called by the insn scheduler during generation of recovery code\n\
1388 for @var{insn}. It should return @code{true}, if the corresponding check\n\
1389 instruction should branch to recovery code, or @code{false} otherwise.",
1390 bool, (unsigned int dep_status), NULL)
1392 /* The following member value is a pointer to a function called
1393 by the insn scheduler. It should return a pattern for the check
1394 instruction.
1395 The first parameter is a speculative instruction, the second parameter
1396 is the label of the corresponding recovery block (or null, if it is a
1397 simple check). The third parameter is the kind of speculation that
1398 is being performed. */
1399 DEFHOOK
1400 (gen_spec_check,
1401 "This hook is called by the insn scheduler to generate a pattern for recovery\n\
1402 check instruction. If @var{mutate_p} is zero, then @var{insn} is a\n\
1403 speculative instruction for which the check should be generated.\n\
1404 @var{label} is either a label of a basic block, where recovery code should\n\
1405 be emitted, or a null pointer, when requested check doesn't branch to\n\
1406 recovery code (a simple check). If @var{mutate_p} is nonzero, then\n\
1407 a pattern for a branchy check corresponding to a simple check denoted by\n\
1408 @var{insn} should be generated. In this case @var{label} can't be null.",
1409 rtx, (rtx insn, rtx label, unsigned int ds), NULL)
1411 /* The following member value is a pointer to a function controlling
1412 what insns from the ready insn queue will be considered for the
1413 multipass insn scheduling. If the hook returns zero for the insn
1414 passed as the parameter, the insn will not be chosen to be
1415 issued. This hook is used to discard speculative instructions,
1416 that stand at the first position of the ready list. */
1417 DEFHOOK
1418 (first_cycle_multipass_dfa_lookahead_guard_spec,
1419 "This hook is used as a workaround for\n\
1420 @samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD_GUARD} not being\n\
1421 called on the first instruction of the ready list. The hook is used to\n\
1422 discard speculative instructions that stand first in the ready list from\n\
1423 being scheduled on the current cycle. If the hook returns @code{false},\n\
1424 @var{insn} will not be chosen to be issued.\n\
1425 For non-speculative instructions,\n\
1426 the hook should always return @code{true}. For example, in the ia64 backend\n\
1427 the hook is used to cancel data speculative insns when the ALAT table\n\
1428 is nearly full.",
1429 bool, (const_rtx insn), NULL)
1431 /* The following member value is a pointer to a function that provides
1432 information about the speculation capabilities of the target.
1433 The parameter is a pointer to spec_info variable. */
1434 DEFHOOK
1435 (set_sched_flags,
1436 "This hook is used by the insn scheduler to find out what features should be\n\
1437 enabled/used.\n\
1438 The structure *@var{spec_info} should be filled in by the target.\n\
1439 The structure describes speculation types that can be used in the scheduler.",
1440 void, (struct spec_info_def *spec_info), NULL)
1442 DEFHOOK_UNDOC
1443 (get_insn_spec_ds,
1444 "Return speculation types of instruction @var{insn}.",
1445 unsigned int, (rtx insn), NULL)
1447 DEFHOOK_UNDOC
1448 (get_insn_checked_ds,
1449 "Return speculation types that are checked for instruction @var{insn}",
1450 unsigned int, (rtx insn), NULL)
1452 DEFHOOK_UNDOC
1453 (skip_rtx_p,
1454 "Return bool if rtx scanning should just skip current layer and\
1455 advance to the inner rtxes.",
1456 bool, (const_rtx x), NULL)
1458 /* The following member value is a pointer to a function that provides
1459 information about the target resource-based lower bound which is
1460 used by the swing modulo scheduler. The parameter is a pointer
1461 to ddg variable. */
1462 DEFHOOK
1463 (sms_res_mii,
1464 "This hook is called by the swing modulo scheduler to calculate a\n\
1465 resource-based lower bound which is based on the resources available in\n\
1466 the machine and the resources required by each instruction. The target\n\
1467 backend can use @var{g} to calculate such bound. A very simple lower\n\
1468 bound will be used in case this hook is not implemented: the total number\n\
1469 of instructions divided by the issue rate.",
1470 int, (struct ddg *g), NULL)
1472 /* The following member value is a function that initializes dispatch
1473 schedling and adds instructions to dispatch window according to its
1474 parameters. */
1475 DEFHOOK
1476 (dispatch_do,
1477 "This hook is called by Haifa Scheduler. It performs the operation specified\n\
1478 in its second parameter.",
1479 void, (rtx insn, int x),
1480 hook_void_rtx_int)
1482 /* The following member value is a a function that returns true is
1483 dispatch schedling is supported in hardware and condition passed
1484 as the second parameter is true. */
1485 DEFHOOK
1486 (dispatch,
1487 "This hook is called by Haifa Scheduler. It returns true if dispatch scheduling\n\
1488 is supported in hardware and the condition specified in the parameter is true.",
1489 bool, (rtx insn, int x),
1490 hook_bool_rtx_int_false)
1492 DEFHOOKPOD
1493 (exposed_pipeline,
1494 "True if the processor has an exposed pipeline, which means that not just\n\
1495 the order of instructions is important for correctness when scheduling, but\n\
1496 also the latencies of operations.",
1497 bool, false)
1499 /* The following member value is a function that returns number
1500 of operations reassociator should try to put in parallel for
1501 statements of the given type. By default 1 is used. */
1502 DEFHOOK
1503 (reassociation_width,
1504 "This hook is called by tree reassociator to determine a level of\n\
1505 parallelism required in output calculations chain.",
1506 int, (unsigned int opc, enum machine_mode mode),
1507 hook_int_uint_mode_1)
1509 HOOK_VECTOR_END (sched)
1511 /* Functions relating to vectorization. */
1512 #undef HOOK_PREFIX
1513 #define HOOK_PREFIX "TARGET_VECTORIZE_"
1514 HOOK_VECTOR (TARGET_VECTORIZE, vectorize)
1516 /* The following member value is a pointer to a function called
1517 by the vectorizer, and return the decl of the target builtin
1518 function. */
1519 DEFHOOK
1520 (builtin_mask_for_load,
1521 "This hook should return the DECL of a function @var{f} that given an\n\
1522 address @var{addr} as an argument returns a mask @var{m} that can be\n\
1523 used to extract from two vectors the relevant data that resides in\n\
1524 @var{addr} in case @var{addr} is not properly aligned.\n\
1526 The autovectorizer, when vectorizing a load operation from an address\n\
1527 @var{addr} that may be unaligned, will generate two vector loads from\n\
1528 the two aligned addresses around @var{addr}. It then generates a\n\
1529 @code{REALIGN_LOAD} operation to extract the relevant data from the\n\
1530 two loaded vectors. The first two arguments to @code{REALIGN_LOAD},\n\
1531 @var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and\n\
1532 the third argument, @var{OFF}, defines how the data will be extracted\n\
1533 from these two vectors: if @var{OFF} is 0, then the returned vector is\n\
1534 @var{v2}; otherwise, the returned vector is composed from the last\n\
1535 @var{VS}-@var{OFF} elements of @var{v1} concatenated to the first\n\
1536 @var{OFF} elements of @var{v2}.\n\
1538 If this hook is defined, the autovectorizer will generate a call\n\
1539 to @var{f} (using the DECL tree that this hook returns) and will\n\
1540 use the return value of @var{f} as the argument @var{OFF} to\n\
1541 @code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}\n\
1542 should comply with the semantics expected by @code{REALIGN_LOAD}\n\
1543 described above.\n\
1544 If this hook is not defined, then @var{addr} will be used as\n\
1545 the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low\n\
1546 log2(@var{VS}) @minus{} 1 bits of @var{addr} will be considered.",
1547 tree, (void), NULL)
1549 /* Returns a code for builtin that realizes vectorized version of
1550 function, or NULL_TREE if not available. */
1551 DEFHOOK
1552 (builtin_vectorized_function,
1553 "This hook should return the decl of a function that implements the\n\
1554 vectorized variant of the builtin function with builtin function code\n\
1555 @var{code} or @code{NULL_TREE} if such a function is not available.\n\
1556 The value of @var{fndecl} is the builtin function declaration. The\n\
1557 return type of the vectorized function shall be of vector type\n\
1558 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1559 tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
1560 default_builtin_vectorized_function)
1562 /* Returns a function declaration for a builtin that realizes the
1563 vector conversion, or NULL_TREE if not available. */
1564 DEFHOOK
1565 (builtin_conversion,
1566 "This hook should return the DECL of a function that implements conversion of the\n\
1567 input vector of type @var{src_type} to type @var{dest_type}.\n\
1568 The value of @var{code} is one of the enumerators in @code{enum tree_code} and\n\
1569 specifies how the conversion is to be applied\n\
1570 (truncation, rounding, etc.).\n\
1572 If this hook is defined, the autovectorizer will use the\n\
1573 @code{TARGET_VECTORIZE_BUILTIN_CONVERSION} target hook when vectorizing\n\
1574 conversion. Otherwise, it will return @code{NULL_TREE}.",
1575 tree, (unsigned code, tree dest_type, tree src_type),
1576 default_builtin_vectorized_conversion)
1578 /* Cost of different vector/scalar statements in vectorization cost
1579 model. In case of misaligned vector loads and stores the cost depends
1580 on the data type and misalignment value. */
1581 DEFHOOK
1582 (builtin_vectorization_cost,
1583 "Returns cost of different scalar or vector statements for vectorization cost model.\n\
1584 For vector memory operations the cost may depend on type (@var{vectype}) and\n\
1585 misalignment value (@var{misalign}).",
1586 int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
1587 default_builtin_vectorization_cost)
1589 /* Return true if vector alignment is reachable (by peeling N
1590 iterations) for the given type. */
1591 DEFHOOK
1592 (vector_alignment_reachable,
1593 "Return true if vector alignment is reachable (by peeling N iterations) for the given type.",
1594 bool, (const_tree type, bool is_packed),
1595 default_builtin_vector_alignment_reachable)
1597 /* Return true if a vector created for vec_perm_const is valid.
1598 A NULL indicates that all constants are valid permutations. */
1599 DEFHOOK
1600 (vec_perm_const_ok,
1601 "Return true if a vector created for @code{vec_perm_const} is valid.",
1602 bool, (enum machine_mode, const unsigned char *sel),
1603 NULL)
1605 /* Return true if the target supports misaligned store/load of a
1606 specific factor denoted in the third parameter. The last parameter
1607 is true if the access is defined in a packed struct. */
1608 DEFHOOK
1609 (support_vector_misalignment,
1610 "This hook should return true if the target supports misaligned vector\n\
1611 store/load of a specific factor denoted in the @var{misalignment}\n\
1612 parameter. The vector store/load should be of machine mode @var{mode} and\n\
1613 the elements in the vectors should be of type @var{type}. @var{is_packed}\n\
1614 parameter is true if the memory access is defined in a packed struct.",
1615 bool,
1616 (enum machine_mode mode, const_tree type, int misalignment, bool is_packed),
1617 default_builtin_support_vector_misalignment)
1619 /* Return the builtin decl needed to load a vector of TYPE. */
1620 DEFHOOK
1621 (builtin_tm_load,
1622 "This hook should return the built-in decl needed to load a vector of the "
1623 "given type within a transaction.",
1624 tree,
1625 (tree),
1626 default_builtin_tm_load_store)
1628 /* Return the builtin decl needed to store a vector of TYPE. */
1629 DEFHOOK
1630 (builtin_tm_store,
1631 "This hook should return the built-in decl needed to store a vector of the "
1632 "given type within a transaction.",
1633 tree,
1634 (tree),
1635 default_builtin_tm_load_store)
1637 /* Returns the preferred mode for SIMD operations for the specified
1638 scalar mode. */
1639 DEFHOOK
1640 (preferred_simd_mode,
1641 "This hook should return the preferred mode for vectorizing scalar\n\
1642 mode @var{mode}. The default is\n\
1643 equal to @code{word_mode}, because the vectorizer can do some\n\
1644 transformations even in absence of specialized @acronym{SIMD} hardware.",
1645 enum machine_mode,
1646 (enum machine_mode mode),
1647 default_preferred_simd_mode)
1649 /* Returns a mask of vector sizes to iterate over when auto-vectorizing
1650 after processing the preferred one derived from preferred_simd_mode. */
1651 DEFHOOK
1652 (autovectorize_vector_sizes,
1653 "This hook should return a mask of sizes that should be iterated over\n\
1654 after trying to autovectorize using the vector size derived from the\n\
1655 mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}.\n\
1656 The default is zero which means to not iterate over other vector sizes.",
1657 unsigned int,
1658 (void),
1659 default_autovectorize_vector_sizes)
1661 /* Target builtin that implements vector gather operation. */
1662 DEFHOOK
1663 (builtin_gather,
1664 "Target builtin that implements vector gather operation. @var{mem_vectype}\n\
1665 is the vector type of the load and @var{index_type} is scalar type of\n\
1666 the index, scaled by @var{scale}.\n\
1667 The default is @code{NULL_TREE} which means to not vectorize gather\n\
1668 loads.",
1669 tree,
1670 (const_tree mem_vectype, const_tree index_type, int scale),
1671 NULL)
1673 /* Target function to initialize the cost model for a loop or block. */
1674 DEFHOOK
1675 (init_cost,
1676 "This hook should initialize target-specific data structures in preparation "
1677 "for modeling the costs of vectorizing a loop or basic block. The default "
1678 "allocates three unsigned integers for accumulating costs for the prologue, "
1679 "body, and epilogue of the loop or basic block. If @var{loop_info} is "
1680 "non-NULL, it identifies the loop being vectorized; otherwise a single block "
1681 "is being vectorized.",
1682 void *,
1683 (struct loop *loop_info),
1684 default_init_cost)
1686 /* Target function to record N statements of the given kind using the
1687 given vector type within the cost model data for the current loop or
1688 block. */
1689 DEFHOOK
1690 (add_stmt_cost,
1691 "This hook should update the target-specific @var{data} in response to "
1692 "adding @var{count} copies of the given @var{kind} of statement to a "
1693 "loop or basic block. The default adds the builtin vectorizer cost for "
1694 "the copies of the statement to the accumulator specified by @var{where}, "
1695 "(the prologue, body, or epilogue) and returns the amount added. The "
1696 "return value should be viewed as a tentative cost that may later be "
1697 "revised.",
1698 unsigned,
1699 (void *data, int count, enum vect_cost_for_stmt kind,
1700 struct _stmt_vec_info *stmt_info, int misalign,
1701 enum vect_cost_model_location where),
1702 default_add_stmt_cost)
1704 /* Target function to calculate the total cost of the current vectorized
1705 loop or block. */
1706 DEFHOOK
1707 (finish_cost,
1708 "This hook should complete calculations of the cost of vectorizing a loop "
1709 "or basic block based on @var{data}, and return the prologue, body, and "
1710 "epilogue costs as unsigned integers. The default returns the value of "
1711 "the three accumulators.",
1712 void,
1713 (void *data, unsigned *prologue_cost, unsigned *body_cost,
1714 unsigned *epilogue_cost),
1715 default_finish_cost)
1717 /* Function to delete target-specific cost modeling data. */
1718 DEFHOOK
1719 (destroy_cost_data,
1720 "This hook should release @var{data} and any related data structures "
1721 "allocated by TARGET_VECTORIZE_INIT_COST. The default releases the "
1722 "accumulator.",
1723 void,
1724 (void *data),
1725 default_destroy_cost_data)
1727 HOOK_VECTOR_END (vectorize)
1729 #undef HOOK_PREFIX
1730 #define HOOK_PREFIX "TARGET_"
1732 /* Allow target specific overriding of option settings after options have
1733 been changed by an attribute or pragma or when it is reset at the
1734 end of the code affected by an attribute or pragma. */
1735 DEFHOOK
1736 (override_options_after_change,
1737 "This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}\n\
1738 but is called when the optimize level is changed via an attribute or\n\
1739 pragma or when it is reset at the end of the code affected by the\n\
1740 attribute or pragma. It is not called at the beginning of compilation\n\
1741 when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these\n\
1742 actions then, you should have @code{TARGET_OPTION_OVERRIDE} call\n\
1743 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.",
1744 void, (void),
1745 hook_void_void)
1747 DEFHOOK_UNDOC
1748 (eh_return_filter_mode,
1749 "Return machine mode for filter value.",
1750 enum machine_mode, (void),
1751 default_eh_return_filter_mode)
1753 /* Return machine mode for libgcc expanded cmp instructions. */
1754 DEFHOOK
1755 (libgcc_cmp_return_mode,
1756 "This target hook should return the mode to be used for the return value\n\
1757 of compare instructions expanded to libgcc calls. If not defined\n\
1758 @code{word_mode} is returned which is the right choice for a majority of\n\
1759 targets.",
1760 enum machine_mode, (void),
1761 default_libgcc_cmp_return_mode)
1763 /* Return machine mode for libgcc expanded shift instructions. */
1764 DEFHOOK
1765 (libgcc_shift_count_mode,
1766 "This target hook should return the mode to be used for the shift count operand\n\
1767 of shift instructions expanded to libgcc calls. If not defined\n\
1768 @code{word_mode} is returned which is the right choice for a majority of\n\
1769 targets.",
1770 enum machine_mode, (void),
1771 default_libgcc_shift_count_mode)
1773 /* Return machine mode to be used for _Unwind_Word type. */
1774 DEFHOOK
1775 (unwind_word_mode,
1776 "Return machine mode to be used for @code{_Unwind_Word} type.\n\
1777 The default is to use @code{word_mode}.",
1778 enum machine_mode, (void),
1779 default_unwind_word_mode)
1781 /* Given two decls, merge their attributes and return the result. */
1782 DEFHOOK
1783 (merge_decl_attributes,
1784 "Define this target hook if the merging of decl attributes needs special\n\
1785 handling. If defined, the result is a list of the combined\n\
1786 @code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.\n\
1787 @var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of\n\
1788 when this is needed are when one attribute overrides another, or when an\n\
1789 attribute is nullified by a subsequent definition. This function may\n\
1790 call @code{merge_attributes} to handle machine-independent merging.\n\
1792 @findex TARGET_DLLIMPORT_DECL_ATTRIBUTES\n\
1793 If the only target-specific handling you require is @samp{dllimport}\n\
1794 for Microsoft Windows targets, you should define the macro\n\
1795 @code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler\n\
1796 will then define a function called\n\
1797 @code{merge_dllimport_decl_attributes} which can then be defined as\n\
1798 the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also\n\
1799 add @code{handle_dll_attribute} in the attribute table for your port\n\
1800 to perform initial processing of the @samp{dllimport} and\n\
1801 @samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and\n\
1802 @file{i386/i386.c}, for example.",
1803 tree, (tree olddecl, tree newdecl),
1804 merge_decl_attributes)
1806 /* Given two types, merge their attributes and return the result. */
1807 DEFHOOK
1808 (merge_type_attributes,
1809 "Define this target hook if the merging of type attributes needs special\n\
1810 handling. If defined, the result is a list of the combined\n\
1811 @code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed\n\
1812 that @code{comptypes} has already been called and returned 1. This\n\
1813 function may call @code{merge_attributes} to handle machine-independent\n\
1814 merging.",
1815 tree, (tree type1, tree type2),
1816 merge_type_attributes)
1818 /* Table of machine attributes and functions to handle them.
1819 Ignored if NULL. */
1820 DEFHOOKPOD
1821 (attribute_table,
1822 "If defined, this target hook points to an array of @samp{struct\n\
1823 attribute_spec} (defined in @file{tree.h}) specifying the machine\n\
1824 specific attributes for this target and some of the restrictions on the\n\
1825 entities to which these attributes are applied and the arguments they\n\
1826 take.",
1827 const struct attribute_spec *, NULL)
1829 /* Return true iff attribute NAME expects a plain identifier as its first
1830 argument. */
1831 DEFHOOK
1832 (attribute_takes_identifier_p,
1833 "If defined, this target hook is a function which returns true if the\n\
1834 machine-specific attribute named @var{name} expects an identifier\n\
1835 given as its first argument to be passed on as a plain identifier, not\n\
1836 subjected to name lookup. If this is not defined, the default is\n\
1837 false for all machine-specific attributes.",
1838 bool, (const_tree name),
1839 hook_bool_const_tree_false)
1841 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
1842 one if they are compatible and two if they are nearly compatible
1843 (which causes a warning to be generated). */
1844 DEFHOOK
1845 (comp_type_attributes,
1846 "If defined, this target hook is a function which returns zero if the attributes on\n\
1847 @var{type1} and @var{type2} are incompatible, one if they are compatible,\n\
1848 and two if they are nearly compatible (which causes a warning to be\n\
1849 generated). If this is not defined, machine-specific attributes are\n\
1850 supposed always to be compatible.",
1851 int, (const_tree type1, const_tree type2),
1852 hook_int_const_tree_const_tree_1)
1854 /* Assign default attributes to the newly defined TYPE. */
1855 DEFHOOK
1856 (set_default_type_attributes,
1857 "If defined, this target hook is a function which assigns default attributes to\n\
1858 the newly defined @var{type}.",
1859 void, (tree type),
1860 hook_void_tree)
1862 /* Insert attributes on the newly created DECL. */
1863 DEFHOOK
1864 (insert_attributes,
1865 "Define this target hook if you want to be able to add attributes to a decl\n\
1866 when it is being created. This is normally useful for back ends which\n\
1867 wish to implement a pragma by using the attributes which correspond to\n\
1868 the pragma's effect. The @var{node} argument is the decl which is being\n\
1869 created. The @var{attr_ptr} argument is a pointer to the attribute list\n\
1870 for this decl. The list itself should not be modified, since it may be\n\
1871 shared with other decls, but attributes may be chained on the head of\n\
1872 the list and @code{*@var{attr_ptr}} modified to point to the new\n\
1873 attributes, or a copy of the list may be made if further changes are\n\
1874 needed.",
1875 void, (tree node, tree *attr_ptr),
1876 hook_void_tree_treeptr)
1878 /* Return true if FNDECL (which has at least one machine attribute)
1879 can be inlined despite its machine attributes, false otherwise. */
1880 DEFHOOK
1881 (function_attribute_inlinable_p,
1882 "@cindex inlining\n\
1883 This target hook returns @code{true} if it is OK to inline @var{fndecl}\n\
1884 into the current function, despite its having target-specific\n\
1885 attributes, @code{false} otherwise. By default, if a function has a\n\
1886 target specific attribute attached to it, it will not be inlined.",
1887 bool, (const_tree fndecl),
1888 hook_bool_const_tree_false)
1890 /* Return true if bitfields in RECORD_TYPE should follow the
1891 Microsoft Visual C++ bitfield layout rules. */
1892 DEFHOOK
1893 (ms_bitfield_layout_p,
1894 "This target hook returns @code{true} if bit-fields in the given\n\
1895 @var{record_type} are to be laid out following the rules of Microsoft\n\
1896 Visual C/C++, namely: (i) a bit-field won't share the same storage\n\
1897 unit with the previous bit-field if their underlying types have\n\
1898 different sizes, and the bit-field will be aligned to the highest\n\
1899 alignment of the underlying types of itself and of the previous\n\
1900 bit-field; (ii) a zero-sized bit-field will affect the alignment of\n\
1901 the whole enclosing structure, even if it is unnamed; except that\n\
1902 (iii) a zero-sized bit-field will be disregarded unless it follows\n\
1903 another bit-field of nonzero size. If this hook returns @code{true},\n\
1904 other macros that control bit-field layout are ignored.\n\
1906 When a bit-field is inserted into a packed record, the whole size\n\
1907 of the underlying type is used by one or more same-size adjacent\n\
1908 bit-fields (that is, if its long:3, 32 bits is used in the record,\n\
1909 and any additional adjacent long bit-fields are packed into the same\n\
1910 chunk of 32 bits. However, if the size changes, a new field of that\n\
1911 size is allocated). In an unpacked record, this is the same as using\n\
1912 alignment, but not equivalent when packing.\n\
1914 If both MS bit-fields and @samp{__attribute__((packed))} are used,\n\
1915 the latter will take precedence. If @samp{__attribute__((packed))} is\n\
1916 used on a single field when MS bit-fields are in use, it will take\n\
1917 precedence for that field, but the alignment of the rest of the structure\n\
1918 may affect its placement.",
1919 bool, (const_tree record_type),
1920 hook_bool_const_tree_false)
1922 /* For now this is only an interface to WORDS_BIG_ENDIAN for
1923 target-independent code like the front ends, need performance testing
1924 before switching completely to the target hook. */
1925 DEFHOOK_UNDOC
1926 (words_big_endian,
1928 bool, (void),
1929 targhook_words_big_endian)
1931 /* Likewise for FLOAT_WORDS_BIG_ENDIAN. */
1932 DEFHOOK_UNDOC
1933 (float_words_big_endian,
1935 bool, (void),
1936 targhook_float_words_big_endian)
1938 /* True if the target supports decimal floating point. */
1939 DEFHOOK
1940 (decimal_float_supported_p,
1941 "Returns true if the target supports decimal floating point.",
1942 bool, (void),
1943 default_decimal_float_supported_p)
1945 /* True if the target supports fixed-point. */
1946 DEFHOOK
1947 (fixed_point_supported_p,
1948 "Returns true if the target supports fixed-point arithmetic.",
1949 bool, (void),
1950 default_fixed_point_supported_p)
1952 /* Return true if anonymous bitfields affect structure alignment. */
1953 DEFHOOK
1954 (align_anon_bitfield,
1955 "When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine\n\
1956 whether unnamed bitfields affect the alignment of the containing\n\
1957 structure. The hook should return true if the structure should inherit\n\
1958 the alignment requirements of an unnamed bitfield's type.",
1959 bool, (void),
1960 hook_bool_void_false)
1962 /* Return true if volatile bitfields should use the narrowest type possible.
1963 Return false if they should use the container type. */
1964 DEFHOOK
1965 (narrow_volatile_bitfield,
1966 "This target hook should return @code{true} if accesses to volatile bitfields\n\
1967 should use the narrowest mode possible. It should return @code{false} if\n\
1968 these accesses should use the bitfield container type.\n\
1970 The default is @code{false}.",
1971 bool, (void),
1972 hook_bool_void_false)
1974 /* Set up target-specific built-in functions. */
1975 DEFHOOK
1976 (init_builtins,
1977 "Define this hook if you have any machine-specific built-in functions\n\
1978 that need to be defined. It should be a function that performs the\n\
1979 necessary setup.\n\
1981 Machine specific built-in functions can be useful to expand special machine\n\
1982 instructions that would otherwise not normally be generated because\n\
1983 they have no equivalent in the source language (for example, SIMD vector\n\
1984 instructions or prefetch instructions).\n\
1986 To create a built-in function, call the function\n\
1987 @code{lang_hooks.builtin_function}\n\
1988 which is defined by the language front end. You can use any type nodes set\n\
1989 up by @code{build_common_tree_nodes};\n\
1990 only language front ends that use those two functions will call\n\
1991 @samp{TARGET_INIT_BUILTINS}.",
1992 void, (void),
1993 hook_void_void)
1995 /* Initialize (if INITIALIZE_P is true) and return the target-specific
1996 built-in function decl for CODE.
1997 Return NULL if that is not possible. Return error_mark_node if CODE
1998 is outside of the range of valid target builtin function codes. */
1999 DEFHOOK
2000 (builtin_decl,
2001 "Define this hook if you have any machine-specific built-in functions\n\
2002 that need to be defined. It should be a function that returns the\n\
2003 builtin function declaration for the builtin function code @var{code}.\n\
2004 If there is no such builtin and it cannot be initialized at this time\n\
2005 if @var{initialize_p} is true the function should return @code{NULL_TREE}.\n\
2006 If @var{code} is out of range the function should return\n\
2007 @code{error_mark_node}.",
2008 tree, (unsigned code, bool initialize_p), NULL)
2010 /* Expand a target-specific builtin. */
2011 DEFHOOK
2012 (expand_builtin,
2013 "\n\
2014 Expand a call to a machine specific built-in function that was set up by\n\
2015 @samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the\n\
2016 function call; the result should go to @var{target} if that is\n\
2017 convenient, and have mode @var{mode} if that is convenient.\n\
2018 @var{subtarget} may be used as the target for computing one of\n\
2019 @var{exp}'s operands. @var{ignore} is nonzero if the value is to be\n\
2020 ignored. This function should return the result of the call to the\n\
2021 built-in function.",
2022 rtx,
2023 (tree exp, rtx target, rtx subtarget, enum machine_mode mode, int ignore),
2024 default_expand_builtin)
2026 /* Select a replacement for a target-specific builtin. This is done
2027 *before* regular type checking, and so allows the target to
2028 implement a crude form of function overloading. The result is a
2029 complete expression that implements the operation. PARAMS really
2030 has type VEC(tree,gc)*, but we don't want to include tree.h here. */
2031 DEFHOOK
2032 (resolve_overloaded_builtin,
2033 "Select a replacement for a machine specific built-in function that\n\
2034 was set up by @samp{TARGET_INIT_BUILTINS}. This is done\n\
2035 @emph{before} regular type checking, and so allows the target to\n\
2036 implement a crude form of function overloading. @var{fndecl} is the\n\
2037 declaration of the built-in function. @var{arglist} is the list of\n\
2038 arguments passed to the built-in function. The result is a\n\
2039 complete expression that implements the operation, usually\n\
2040 another @code{CALL_EXPR}.\n\
2041 @var{arglist} really has type @samp{VEC(tree,gc)*}",
2042 tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
2044 /* Fold a target-specific builtin to a tree valid for both GIMPLE
2045 and GENERIC. */
2046 DEFHOOK
2047 (fold_builtin,
2048 "Fold a call to a machine specific built-in function that was set up by\n\
2049 @samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the\n\
2050 built-in function. @var{n_args} is the number of arguments passed to\n\
2051 the function; the arguments themselves are pointed to by @var{argp}.\n\
2052 The result is another tree, valid for both GIMPLE and GENERIC,\n\
2053 containing a simplified expression for the call's result. If\n\
2054 @var{ignore} is true the value will be ignored.",
2055 tree, (tree fndecl, int n_args, tree *argp, bool ignore),
2056 hook_tree_tree_int_treep_bool_null)
2058 /* Fold a target-specific builtin to a valid GIMPLE tree. */
2059 DEFHOOK
2060 (gimple_fold_builtin,
2061 "Fold a call to a machine specific built-in function that was set up\n\
2062 by @samp{TARGET_INIT_BUILTINS}. @var{gsi} points to the gimple\n\
2063 statement holding the function call. Returns true if any change\n\
2064 was made to the GIMPLE stream.",
2065 bool, (gimple_stmt_iterator *gsi),
2066 hook_bool_gsiptr_false)
2068 /* Target hook is used to compare the target attributes in two functions to
2069 determine which function's features get higher priority. This is used
2070 during function multi-versioning to figure out the order in which two
2071 versions must be dispatched. A function version with a higher priority
2072 is checked for dispatching earlier. DECL1 and DECL2 are
2073 the two function decls that will be compared. It returns positive value
2074 if DECL1 is higher priority, negative value if DECL2 is higher priority
2075 and 0 if they are the same. */
2076 DEFHOOK
2077 (compare_version_priority,
2078 "This hook is used to compare the target attributes in two functions to\n\
2079 determine which function's features get higher priority. This is used\n\
2080 during function multi-versioning to figure out the order in which two\n\
2081 versions must be dispatched. A function version with a higher priority\n\
2082 is checked for dispatching earlier. @var{decl1} and @var{decl2} are\n\
2083 the two function decls that will be compared.",
2084 int, (tree decl1, tree decl2), NULL)
2086 /* Target hook is used to generate the dispatcher logic to invoke the right
2087 function version at run-time for a given set of function versions.
2088 ARG points to the callgraph node of the dispatcher function whose body
2089 must be generated. */
2090 DEFHOOK
2091 (generate_version_dispatcher_body,
2092 "This hook is used to generate the dispatcher logic to invoke the right\n\
2093 function version at run-time for a given set of function versions.\n\
2094 @var{arg} points to the callgraph node of the dispatcher function whose\n\
2095 body must be generated.",
2096 tree, (void *arg), NULL)
2098 /* Target hook is used to get the dispatcher function for a set of function
2099 versions. The dispatcher function is called to invoke the right function
2100 version at run-time. DECL is one version from a set of semantically
2101 identical versions. */
2102 DEFHOOK
2103 (get_function_versions_dispatcher,
2104 "This hook is used to get the dispatcher function for a set of function\n\
2105 versions. The dispatcher function is called to invoke the right function\n\
2106 version at run-time. @var{decl} is one version from a set of semantically\n\
2107 identical versions.",
2108 tree, (void *decl), NULL)
2110 /* Returns a code for a target-specific builtin that implements
2111 reciprocal of the function, or NULL_TREE if not available. */
2112 DEFHOOK
2113 (builtin_reciprocal,
2114 "This hook should return the DECL of a function that implements reciprocal of\n\
2115 the builtin function with builtin function code @var{fn}, or\n\
2116 @code{NULL_TREE} if such a function is not available. @var{md_fn} is true\n\
2117 when @var{fn} is a code of a machine-dependent builtin function. When\n\
2118 @var{sqrt} is true, additional optimizations that apply only to the reciprocal\n\
2119 of a square root function are performed, and only reciprocals of @code{sqrt}\n\
2120 function are valid.",
2121 tree, (unsigned fn, bool md_fn, bool sqrt),
2122 default_builtin_reciprocal)
2124 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
2125 string containing the C++ mangling for TYPE. In all other cases, return
2126 NULL. */
2127 DEFHOOK
2128 (mangle_type,
2129 "If your target defines any fundamental types, or any types your target\n\
2130 uses should be mangled differently from the default, define this hook\n\
2131 to return the appropriate encoding for these types as part of a C++\n\
2132 mangled name. The @var{type} argument is the tree structure representing\n\
2133 the type to be mangled. The hook may be applied to trees which are\n\
2134 not target-specific fundamental types; it should return @code{NULL}\n\
2135 for all such types, as well as arguments it does not recognize. If the\n\
2136 return value is not @code{NULL}, it must point to a statically-allocated\n\
2137 string constant.\n\
2139 Target-specific fundamental types might be new fundamental types or\n\
2140 qualified versions of ordinary fundamental types. Encode new\n\
2141 fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}\n\
2142 is the name used for the type in source code, and @var{n} is the\n\
2143 length of @var{name} in decimal. Encode qualified versions of\n\
2144 ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where\n\
2145 @var{name} is the name used for the type qualifier in source code,\n\
2146 @var{n} is the length of @var{name} as above, and @var{code} is the\n\
2147 code used to represent the unqualified version of this type. (See\n\
2148 @code{write_builtin_type} in @file{cp/mangle.c} for the list of\n\
2149 codes.) In both cases the spaces are for clarity; do not include any\n\
2150 spaces in your string.\n\
2152 This hook is applied to types prior to typedef resolution. If the mangled\n\
2153 name for a particular type depends only on that type's main variant, you\n\
2154 can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}\n\
2155 before mangling.\n\
2157 The default version of this hook always returns @code{NULL}, which is\n\
2158 appropriate for a target that does not define any new fundamental\n\
2159 types.",
2160 const char *, (const_tree type),
2161 hook_constcharptr_const_tree_null)
2163 /* Make any adjustments to libfunc names needed for this target. */
2164 DEFHOOK
2165 (init_libfuncs,
2166 "This hook should declare additional library routines or rename\n\
2167 existing ones, using the functions @code{set_optab_libfunc} and\n\
2168 @code{init_one_libfunc} defined in @file{optabs.c}.\n\
2169 @code{init_optabs} calls this macro after initializing all the normal\n\
2170 library routines.\n\
2172 The default is to do nothing. Most ports don't need to define this hook.",
2173 void, (void),
2174 hook_void_void)
2176 /* Add a __gnu_ prefix to library functions rather than just __. */
2177 DEFHOOKPOD
2178 (libfunc_gnu_prefix,
2179 "If false (the default), internal library routines start with two\n\
2180 underscores. If set to true, these routines start with @code{__gnu_}\n\
2181 instead. E.g., @code{__muldi3} changes to @code{__gnu_muldi3}. This\n\
2182 currently only affects functions defined in @file{libgcc2.c}. If this\n\
2183 is set to true, the @file{tm.h} file must also\n\
2184 @code{#define LIBGCC2_GNU_PREFIX}.",
2185 bool, false)
2187 /* Given a decl, a section name, and whether the decl initializer
2188 has relocs, choose attributes for the section. */
2189 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
2190 DEFHOOK
2191 (section_type_flags,
2192 "Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}\n\
2193 based on a variable or function decl, a section name, and whether or not the\n\
2194 declaration's initializer may contain runtime relocations. @var{decl} may be\n\
2195 null, in which case read-write data should be assumed.\n\
2197 The default version of this function handles choosing code vs data,\n\
2198 read-only vs read-write data, and @code{flag_pic}. You should only\n\
2199 need to override this if your target has special flags that might be\n\
2200 set via @code{__attribute__}.",
2201 unsigned int, (tree decl, const char *name, int reloc),
2202 default_section_type_flags)
2204 DEFHOOK
2205 (libc_has_function,
2206 "This hook determines whether a function from a class of functions\n\
2207 @var{fn_class} is present at the runtime.",
2208 bool, (enum function_class fn_class),
2209 default_libc_has_function)
2211 /* True if new jumps cannot be created, to replace existing ones or
2212 not, at the current point in the compilation. */
2213 DEFHOOK
2214 (cannot_modify_jumps_p,
2215 "This target hook returns @code{true} past the point in which new jump\n\
2216 instructions could be created. On machines that require a register for\n\
2217 every jump such as the SHmedia ISA of SH5, this point would typically be\n\
2218 reload, so this target hook should be defined to a function such as:\n\
2220 @smallexample\n\
2221 static bool\n\
2222 cannot_modify_jumps_past_reload_p ()\n\
2223 @{\n\
2224 return (reload_completed || reload_in_progress);\n\
2225 @}\n\
2226 @end smallexample",
2227 bool, (void),
2228 hook_bool_void_false)
2230 /* True if FOLLOWER may be modified to follow FOLLOWEE. */
2231 DEFHOOK
2232 (can_follow_jump,
2233 "FOLLOWER and FOLLOWEE are JUMP_INSN instructions;\
2234 return true if FOLLOWER may be modified to follow FOLLOWEE;\
2235 false, if it can't.\
2236 For example, on some targets, certain kinds of branches can't be made to\
2237 follow through a hot/cold partitioning.",
2238 bool, (const_rtx follower, const_rtx followee),
2239 hook_bool_const_rtx_const_rtx_true)
2241 /* Return a register class for which branch target register
2242 optimizations should be applied. */
2243 DEFHOOK
2244 (branch_target_register_class,
2245 "This target hook returns a register class for which branch target register\n\
2246 optimizations should be applied. All registers in this class should be\n\
2247 usable interchangeably. After reload, registers in this class will be\n\
2248 re-allocated and loads will be hoisted out of loops and be subjected\n\
2249 to inter-block scheduling.",
2250 reg_class_t, (void),
2251 default_branch_target_register_class)
2253 /* Return true if branch target register optimizations should include
2254 callee-saved registers that are not already live during the current
2255 function. AFTER_PE_GEN is true if prologues and epilogues have
2256 already been generated. */
2257 DEFHOOK
2258 (branch_target_register_callee_saved,
2259 "Branch target register optimization will by default exclude callee-saved\n\
2260 registers\n\
2261 that are not already live during the current function; if this target hook\n\
2262 returns true, they will be included. The target code must than make sure\n\
2263 that all target registers in the class returned by\n\
2264 @samp{TARGET_BRANCH_TARGET_REGISTER_CLASS} that might need saving are\n\
2265 saved. @var{after_prologue_epilogue_gen} indicates if prologues and\n\
2266 epilogues have already been generated. Note, even if you only return\n\
2267 true when @var{after_prologue_epilogue_gen} is false, you still are likely\n\
2268 to have to make special provisions in @code{INITIAL_ELIMINATION_OFFSET}\n\
2269 to reserve space for caller-saved target registers.",
2270 bool, (bool after_prologue_epilogue_gen),
2271 hook_bool_bool_false)
2273 /* Return true if the target supports conditional execution. */
2274 DEFHOOK
2275 (have_conditional_execution,
2276 "This target hook returns true if the target supports conditional execution.\n\
2277 This target hook is required only when the target has several different\n\
2278 modes and they have different conditional execution capability, such as ARM.",
2279 bool, (void),
2280 default_have_conditional_execution)
2282 /* Return a new value for loop unroll size. */
2283 DEFHOOK
2284 (loop_unroll_adjust,
2285 "This target hook returns a new value for the number of times @var{loop}\n\
2286 should be unrolled. The parameter @var{nunroll} is the number of times\n\
2287 the loop is to be unrolled. The parameter @var{loop} is a pointer to\n\
2288 the loop, which is going to be checked for unrolling. This target hook\n\
2289 is required only when the target has special constraints like maximum\n\
2290 number of memory accesses.",
2291 unsigned, (unsigned nunroll, struct loop *loop),
2292 NULL)
2294 /* True if X is a legitimate MODE-mode immediate operand. */
2295 DEFHOOK
2296 (legitimate_constant_p,
2297 "This hook returns true if @var{x} is a legitimate constant for a\n\
2298 @var{mode}-mode immediate operand on the target machine. You can assume that\n\
2299 @var{x} satisfies @code{CONSTANT_P}, so you need not check this.\n\
2301 The default definition returns true.",
2302 bool, (enum machine_mode mode, rtx x),
2303 hook_bool_mode_rtx_true)
2305 /* True if the constant X cannot be placed in the constant pool. */
2306 DEFHOOK
2307 (cannot_force_const_mem,
2308 "This hook should return true if @var{x} is of a form that cannot (or\n\
2309 should not) be spilled to the constant pool. @var{mode} is the mode\n\
2310 of @var{x}.\n\
2312 The default version of this hook returns false.\n\
2314 The primary reason to define this hook is to prevent reload from\n\
2315 deciding that a non-legitimate constant would be better reloaded\n\
2316 from the constant pool instead of spilling and reloading a register\n\
2317 holding the constant. This restriction is often true of addresses\n\
2318 of TLS symbols for various targets.",
2319 bool, (enum machine_mode mode, rtx x),
2320 hook_bool_mode_rtx_false)
2322 DEFHOOK_UNDOC
2323 (cannot_copy_insn_p,
2324 "True if the insn @var{x} cannot be duplicated.",
2325 bool, (rtx), NULL)
2327 /* True if X is considered to be commutative. */
2328 DEFHOOK
2329 (commutative_p,
2330 "This target hook returns @code{true} if @var{x} is considered to be commutative.\n\
2331 Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider\n\
2332 PLUS to be commutative inside a MEM@. @var{outer_code} is the rtx code\n\
2333 of the enclosing rtl, if known, otherwise it is UNKNOWN.",
2334 bool, (const_rtx x, int outer_code),
2335 hook_bool_const_rtx_commutative_p)
2337 /* True if ADDR is an address-expression whose effect depends
2338 on the mode of the memory reference it is used in. */
2339 DEFHOOK
2340 (mode_dependent_address_p,
2341 "This hook returns @code{true} if memory address @var{addr} in address\n\
2342 space @var{addrspace} can have\n\
2343 different meanings depending on the machine mode of the memory\n\
2344 reference it is used for or if the address is valid for some modes\n\
2345 but not others.\n\
2347 Autoincrement and autodecrement addresses typically have mode-dependent\n\
2348 effects because the amount of the increment or decrement is the size\n\
2349 of the operand being addressed. Some machines have other mode-dependent\n\
2350 addresses. Many RISC machines have no mode-dependent addresses.\n\
2352 You may assume that @var{addr} is a valid address for the machine.\n\
2354 The default version of this hook returns @code{false}.",
2355 bool, (const_rtx addr, addr_space_t addrspace),
2356 default_mode_dependent_address_p)
2358 /* Given an invalid address X for a given machine mode, try machine-specific
2359 ways to make it legitimate. Return X or an invalid address on failure. */
2360 DEFHOOK
2361 (legitimize_address,
2362 "This hook is given an invalid memory address @var{x} for an\n\
2363 operand of mode @var{mode} and should try to return a valid memory\n\
2364 address.\n\
2366 @findex break_out_memory_refs\n\
2367 @var{x} will always be the result of a call to @code{break_out_memory_refs},\n\
2368 and @var{oldx} will be the operand that was given to that function to produce\n\
2369 @var{x}.\n\
2371 The code of the hook should not alter the substructure of\n\
2372 @var{x}. If it transforms @var{x} into a more legitimate form, it\n\
2373 should return the new @var{x}.\n\
2375 It is not necessary for this hook to come up with a legitimate address,\n\
2376 with the exception of native TLS addresses (@pxref{Emulated TLS}).\n\
2377 The compiler has standard ways of doing so in all cases. In fact, if\n\
2378 the target supports only emulated TLS, it\n\
2379 is safe to omit this hook or make it return @var{x} if it cannot find\n\
2380 a valid way to legitimize the address. But often a machine-dependent\n\
2381 strategy can generate better code.",
2382 rtx, (rtx x, rtx oldx, enum machine_mode mode),
2383 default_legitimize_address)
2385 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
2386 DEFHOOK
2387 (delegitimize_address,
2388 "This hook is used to undo the possibly obfuscating effects of the\n\
2389 @code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target\n\
2390 macros. Some backend implementations of these macros wrap symbol\n\
2391 references inside an @code{UNSPEC} rtx to represent PIC or similar\n\
2392 addressing modes. This target hook allows GCC's optimizers to understand\n\
2393 the semantics of these opaque @code{UNSPEC}s by converting them back\n\
2394 into their original form.",
2395 rtx, (rtx x),
2396 delegitimize_mem_from_attrs)
2398 /* Given an RTX, return true if it is not ok to emit it into debug info
2399 section. */
2400 DEFHOOK
2401 (const_not_ok_for_debug_p,
2402 "This hook should return true if @var{x} should not be emitted into\n\
2403 debug sections.",
2404 bool, (rtx x),
2405 hook_bool_rtx_false)
2407 /* Given an address RTX, say whether it is valid. */
2408 DEFHOOK
2409 (legitimate_address_p,
2410 "A function that returns whether @var{x} (an RTX) is a legitimate memory\n\
2411 address on the target machine for a memory operand of mode @var{mode}.\n\
2413 Legitimate addresses are defined in two variants: a strict variant and a\n\
2414 non-strict one. The @var{strict} parameter chooses which variant is\n\
2415 desired by the caller.\n\
2417 The strict variant is used in the reload pass. It must be defined so\n\
2418 that any pseudo-register that has not been allocated a hard register is\n\
2419 considered a memory reference. This is because in contexts where some\n\
2420 kind of register is required, a pseudo-register with no hard register\n\
2421 must be rejected. For non-hard registers, the strict variant should look\n\
2422 up the @code{reg_renumber} array; it should then proceed using the hard\n\
2423 register number in the array, or treat the pseudo as a memory reference\n\
2424 if the array holds @code{-1}.\n\
2426 The non-strict variant is used in other passes. It must be defined to\n\
2427 accept all pseudo-registers in every context where some kind of\n\
2428 register is required.\n\
2430 Normally, constant addresses which are the sum of a @code{symbol_ref}\n\
2431 and an integer are stored inside a @code{const} RTX to mark them as\n\
2432 constant. Therefore, there is no need to recognize such sums\n\
2433 specifically as legitimate addresses. Normally you would simply\n\
2434 recognize any @code{const} as legitimate.\n\
2436 Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant\n\
2437 sums that are not marked with @code{const}. It assumes that a naked\n\
2438 @code{plus} indicates indexing. If so, then you @emph{must} reject such\n\
2439 naked constant sums as illegitimate addresses, so that none of them will\n\
2440 be given to @code{PRINT_OPERAND_ADDRESS}.\n\
2442 @cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation\n\
2443 On some machines, whether a symbolic address is legitimate depends on\n\
2444 the section that the address refers to. On these machines, define the\n\
2445 target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information\n\
2446 into the @code{symbol_ref}, and then check for it here. When you see a\n\
2447 @code{const}, you will have to look inside it to find the\n\
2448 @code{symbol_ref} in order to determine the section. @xref{Assembler\n\
2449 Format}.\n\
2451 @cindex @code{GO_IF_LEGITIMATE_ADDRESS}\n\
2452 Some ports are still using a deprecated legacy substitute for\n\
2453 this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro. This macro\n\
2454 has this syntax:\n\
2456 @example\n\
2457 #define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})\n\
2458 @end example\n\
2460 @noindent\n\
2461 and should @code{goto @var{label}} if the address @var{x} is a valid\n\
2462 address on the target machine for a memory operand of mode @var{mode}.\n\
2464 @findex REG_OK_STRICT\n\
2465 Compiler source files that want to use the strict variant of this\n\
2466 macro define the macro @code{REG_OK_STRICT}. You should use an\n\
2467 @code{#ifdef REG_OK_STRICT} conditional to define the strict variant in\n\
2468 that case and the non-strict variant otherwise.\n\
2470 Using the hook is usually simpler because it limits the number of\n\
2471 files that are recompiled when changes are made.",
2472 bool, (enum machine_mode mode, rtx x, bool strict),
2473 default_legitimate_address_p)
2475 /* True if the given constant can be put into an object_block. */
2476 DEFHOOK
2477 (use_blocks_for_constant_p,
2478 "This hook should return true if pool entries for constant @var{x} can\n\
2479 be placed in an @code{object_block} structure. @var{mode} is the mode\n\
2480 of @var{x}.\n\
2482 The default version returns false for all constants.",
2483 bool, (enum machine_mode mode, const_rtx x),
2484 hook_bool_mode_const_rtx_false)
2486 /* True if the given decl can be put into an object_block. */
2487 DEFHOOK
2488 (use_blocks_for_decl_p,
2489 "This hook should return true if pool entries for @var{decl} should\n\
2490 be placed in an @code{object_block} structure.\n\
2492 The default version returns true for all decls.",
2493 bool, (const_tree decl),
2494 hook_bool_const_tree_true)
2496 /* The minimum and maximum byte offsets for anchored addresses. */
2497 DEFHOOKPOD
2498 (min_anchor_offset,
2499 "The minimum offset that should be applied to a section anchor.\n\
2500 On most targets, it should be the smallest offset that can be\n\
2501 applied to a base register while still giving a legitimate address\n\
2502 for every mode. The default value is 0.",
2503 HOST_WIDE_INT, 0)
2505 DEFHOOKPOD
2506 (max_anchor_offset,
2507 "Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)\n\
2508 offset that should be applied to section anchors. The default\n\
2509 value is 0.",
2510 HOST_WIDE_INT, 0)
2512 /* True if section anchors can be used to access the given symbol. */
2513 DEFHOOK
2514 (use_anchors_for_symbol_p,
2515 "Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}\n\
2516 @var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and\n\
2517 @samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.\n\
2519 The default version is correct for most targets, but you might need to\n\
2520 intercept this hook to handle things like target-specific attributes\n\
2521 or target-specific sections.",
2522 bool, (const_rtx x),
2523 default_use_anchors_for_symbol_p)
2525 /* True if target supports indirect functions. */
2526 DEFHOOK
2527 (has_ifunc_p,
2528 "It returns true if the target supports GNU indirect functions.\n\
2529 The support includes the assembler, linker and dynamic linker.\n\
2530 The default value of this hook is based on target's libc.",
2531 bool, (void),
2532 default_has_ifunc_p)
2534 /* True if it is OK to do sibling call optimization for the specified
2535 call expression EXP. DECL will be the called function, or NULL if
2536 this is an indirect call. */
2537 DEFHOOK
2538 (function_ok_for_sibcall,
2539 "True if it is OK to do sibling call optimization for the specified\n\
2540 call expression @var{exp}. @var{decl} will be the called function,\n\
2541 or @code{NULL} if this is an indirect call.\n\
2543 It is not uncommon for limitations of calling conventions to prevent\n\
2544 tail calls to functions outside the current unit of translation, or\n\
2545 during PIC compilation. The hook is used to enforce these restrictions,\n\
2546 as the @code{sibcall} md pattern can not fail, or fall over to a\n\
2547 ``normal'' call. The criteria for successful sibling call optimization\n\
2548 may vary greatly between different architectures.",
2549 bool, (tree decl, tree exp),
2550 hook_bool_tree_tree_false)
2552 /* Establish appropriate back-end context for processing the function
2553 FNDECL. The argument might be NULL to indicate processing at top
2554 level, outside of any function scope. */
2555 DEFHOOK
2556 (set_current_function,
2557 "The compiler invokes this hook whenever it changes its current function\n\
2558 context (@code{cfun}). You can define this function if\n\
2559 the back end needs to perform any initialization or reset actions on a\n\
2560 per-function basis. For example, it may be used to implement function\n\
2561 attributes that affect register usage or code generation patterns.\n\
2562 The argument @var{decl} is the declaration for the new function context,\n\
2563 and may be null to indicate that the compiler has left a function context\n\
2564 and is returning to processing at the top level.\n\
2565 The default hook function does nothing.\n\
2567 GCC sets @code{cfun} to a dummy function context during initialization of\n\
2568 some parts of the back end. The hook function is not invoked in this\n\
2569 situation; you need not worry about the hook being invoked recursively,\n\
2570 or when the back end is in a partially-initialized state.\n\
2571 @code{cfun} might be @code{NULL} to indicate processing at top level,\n\
2572 outside of any function scope.",
2573 void, (tree decl), hook_void_tree)
2575 /* True if EXP should be placed in a "small data" section. */
2576 DEFHOOK
2577 (in_small_data_p,
2578 "Returns true if @var{exp} should be placed into a ``small data'' section.\n\
2579 The default version of this hook always returns false.",
2580 bool, (const_tree exp),
2581 hook_bool_const_tree_false)
2583 /* True if EXP names an object for which name resolution must resolve
2584 to the current executable or shared library. */
2585 DEFHOOK
2586 (binds_local_p,
2587 "Returns true if @var{exp} names an object for which name resolution\n\
2588 rules must resolve to the current ``module'' (dynamic shared library\n\
2589 or executable image).\n\
2591 The default version of this hook implements the name resolution rules\n\
2592 for ELF, which has a looser model of global name binding than other\n\
2593 currently supported object file formats.",
2594 bool, (const_tree exp),
2595 default_binds_local_p)
2597 /* Check if profiling code is before or after prologue. */
2598 DEFHOOK
2599 (profile_before_prologue,
2600 "It returns true if target wants profile code emitted before prologue.\n\n\
2601 The default version of this hook use the target macro\n\
2602 @code{PROFILE_BEFORE_PROLOGUE}.",
2603 bool, (void),
2604 default_profile_before_prologue)
2606 /* Modify and return the identifier of a DECL's external name,
2607 originally identified by ID, as required by the target,
2608 (eg, append @nn to windows32 stdcall function names).
2609 The default is to return ID without modification. */
2610 DEFHOOK
2611 (mangle_decl_assembler_name,
2612 "Define this hook if you need to postprocess the assembler name generated\n\
2613 by target-independent code. The @var{id} provided to this hook will be\n\
2614 the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,\n\
2615 or the mangled name of the @var{decl} in C++). The return value of the\n\
2616 hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on\n\
2617 your target system. The default implementation of this hook just\n\
2618 returns the @var{id} provided.",
2619 tree, (tree decl, tree id),
2620 default_mangle_decl_assembler_name)
2622 /* Do something target-specific to record properties of the DECL into
2623 the associated SYMBOL_REF. */
2624 DEFHOOK
2625 (encode_section_info,
2626 "Define this hook if references to a symbol or a constant must be\n\
2627 treated differently depending on something about the variable or\n\
2628 function named by the symbol (such as what section it is in).\n\
2630 The hook is executed immediately after rtl has been created for\n\
2631 @var{decl}, which may be a variable or function declaration or\n\
2632 an entry in the constant pool. In either case, @var{rtl} is the\n\
2633 rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}\n\
2634 in this hook; that field may not have been initialized yet.\n\
2636 In the case of a constant, it is safe to assume that the rtl is\n\
2637 a @code{mem} whose address is a @code{symbol_ref}. Most decls\n\
2638 will also have this form, but that is not guaranteed. Global\n\
2639 register variables, for instance, will have a @code{reg} for their\n\
2640 rtl. (Normally the right thing to do with such unusual rtl is\n\
2641 leave it alone.)\n\
2643 The @var{new_decl_p} argument will be true if this is the first time\n\
2644 that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will\n\
2645 be false for subsequent invocations, which will happen for duplicate\n\
2646 declarations. Whether or not anything must be done for the duplicate\n\
2647 declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.\n\
2648 @var{new_decl_p} is always true when the hook is called for a constant.\n\
2650 @cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}\n\
2651 The usual thing for this hook to do is to record flags in the\n\
2652 @code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.\n\
2653 Historically, the name string was modified if it was necessary to\n\
2654 encode more than one bit of information, but this practice is now\n\
2655 discouraged; use @code{SYMBOL_REF_FLAGS}.\n\
2657 The default definition of this hook, @code{default_encode_section_info}\n\
2658 in @file{varasm.c}, sets a number of commonly-useful bits in\n\
2659 @code{SYMBOL_REF_FLAGS}. Check whether the default does what you need\n\
2660 before overriding it.",
2661 void, (tree decl, rtx rtl, int new_decl_p),
2662 default_encode_section_info)
2664 /* Undo the effects of encode_section_info on the symbol string. */
2665 DEFHOOK
2666 (strip_name_encoding,
2667 "Decode @var{name} and return the real name part, sans\n\
2668 the characters that @code{TARGET_ENCODE_SECTION_INFO}\n\
2669 may have added.",
2670 const char *, (const char *name),
2671 default_strip_name_encoding)
2673 /* If shift optabs for MODE are known to always truncate the shift count,
2674 return the mask that they apply. Return 0 otherwise. */
2675 DEFHOOK
2676 (shift_truncation_mask,
2677 "This function describes how the standard shift patterns for @var{mode}\n\
2678 deal with shifts by negative amounts or by more than the width of the mode.\n\
2679 @xref{shift patterns}.\n\
2681 On many machines, the shift patterns will apply a mask @var{m} to the\n\
2682 shift count, meaning that a fixed-width shift of @var{x} by @var{y} is\n\
2683 equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If\n\
2684 this is true for mode @var{mode}, the function should return @var{m},\n\
2685 otherwise it should return 0. A return value of 0 indicates that no\n\
2686 particular behavior is guaranteed.\n\
2688 Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does\n\
2689 @emph{not} apply to general shift rtxes; it applies only to instructions\n\
2690 that are generated by the named shift patterns.\n\
2692 The default implementation of this function returns\n\
2693 @code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}\n\
2694 and 0 otherwise. This definition is always safe, but if\n\
2695 @code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns\n\
2696 nevertheless truncate the shift count, you may get better code\n\
2697 by overriding it.",
2698 unsigned HOST_WIDE_INT, (enum machine_mode mode),
2699 default_shift_truncation_mask)
2701 /* Return the number of divisions in the given MODE that should be present,
2702 so that it is profitable to turn the division into a multiplication by
2703 the reciprocal. */
2704 DEFHOOK
2705 (min_divisions_for_recip_mul,
2706 "When @option{-ffast-math} is in effect, GCC tries to optimize\n\
2707 divisions by the same divisor, by turning them into multiplications by\n\
2708 the reciprocal. This target hook specifies the minimum number of divisions\n\
2709 that should be there for GCC to perform the optimization for a variable\n\
2710 of mode @var{mode}. The default implementation returns 3 if the machine\n\
2711 has an instruction for the division, and 2 if it does not.",
2712 unsigned int, (enum machine_mode mode),
2713 default_min_divisions_for_recip_mul)
2715 /* If the representation of integral MODE is such that values are
2716 always sign-extended to a wider mode MODE_REP then return
2717 SIGN_EXTEND. Return UNKNOWN otherwise. */
2718 /* Note that the return type ought to be RTX_CODE, but that's not
2719 necessarily defined at this point. */
2720 DEFHOOK
2721 (mode_rep_extended,
2722 "The representation of an integral mode can be such that the values\n\
2723 are always extended to a wider integral mode. Return\n\
2724 @code{SIGN_EXTEND} if values of @var{mode} are represented in\n\
2725 sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}\n\
2726 otherwise. (Currently, none of the targets use zero-extended\n\
2727 representation this way so unlike @code{LOAD_EXTEND_OP},\n\
2728 @code{TARGET_MODE_REP_EXTENDED} is expected to return either\n\
2729 @code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends\n\
2730 @var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next\n\
2731 widest integral mode and currently we take advantage of this fact.)\n\
2733 Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}\n\
2734 value even if the extension is not performed on certain hard registers\n\
2735 as long as for the @code{REGNO_REG_CLASS} of these hard registers\n\
2736 @code{CANNOT_CHANGE_MODE_CLASS} returns nonzero.\n\
2738 Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}\n\
2739 describe two related properties. If you define\n\
2740 @code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want\n\
2741 to define @code{LOAD_EXTEND_OP (mode)} to return the same type of\n\
2742 extension.\n\
2744 In order to enforce the representation of @code{mode},\n\
2745 @code{TRULY_NOOP_TRUNCATION} should return false when truncating to\n\
2746 @code{mode}.",
2747 int, (enum machine_mode mode, enum machine_mode rep_mode),
2748 default_mode_rep_extended)
2750 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
2751 DEFHOOK
2752 (valid_pointer_mode,
2753 "Define this to return nonzero if the port can handle pointers\n\
2754 with machine mode @var{mode}. The default version of this\n\
2755 hook returns true for both @code{ptr_mode} and @code{Pmode}.",
2756 bool, (enum machine_mode mode),
2757 default_valid_pointer_mode)
2759 /* Disambiguate with errno. */
2760 DEFHOOK
2761 (ref_may_alias_errno,
2762 "Define this to return nonzero if the memory reference @var{ref}\
2763 may alias with the system C library errno location. The default\
2764 version of this hook assumes the system C library errno location\
2765 is either a declaration of type int or accessed by dereferencing\
2766 a pointer to int.",
2767 bool, (struct ao_ref_s *ref),
2768 default_ref_may_alias_errno)
2770 /* Support for named address spaces. */
2771 #undef HOOK_PREFIX
2772 #define HOOK_PREFIX "TARGET_ADDR_SPACE_"
2773 HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)
2775 /* MODE to use for a pointer into another address space. */
2776 DEFHOOK
2777 (pointer_mode,
2778 "Define this to return the machine mode to use for pointers to\n\
2779 @var{address_space} if the target supports named address spaces.\n\
2780 The default version of this hook returns @code{ptr_mode} for the\n\
2781 generic address space only.",
2782 enum machine_mode, (addr_space_t address_space),
2783 default_addr_space_pointer_mode)
2785 /* MODE to use for an address in another address space. */
2786 DEFHOOK
2787 (address_mode,
2788 "Define this to return the machine mode to use for addresses in\n\
2789 @var{address_space} if the target supports named address spaces.\n\
2790 The default version of this hook returns @code{Pmode} for the\n\
2791 generic address space only.",
2792 enum machine_mode, (addr_space_t address_space),
2793 default_addr_space_address_mode)
2795 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
2796 in another address space. */
2797 DEFHOOK
2798 (valid_pointer_mode,
2799 "Define this to return nonzero if the port can handle pointers\n\
2800 with machine mode @var{mode} to address space @var{as}. This target\n\
2801 hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,\n\
2802 except that it includes explicit named address space support. The default\n\
2803 version of this hook returns true for the modes returned by either the\n\
2804 @code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}\n\
2805 target hooks for the given address space.",
2806 bool, (enum machine_mode mode, addr_space_t as),
2807 default_addr_space_valid_pointer_mode)
2809 /* True if an address is a valid memory address to a given named address
2810 space for a given mode. */
2811 DEFHOOK
2812 (legitimate_address_p,
2813 "Define this to return true if @var{exp} is a valid address for mode\n\
2814 @var{mode} in the named address space @var{as}. The @var{strict}\n\
2815 parameter says whether strict addressing is in effect after reload has\n\
2816 finished. This target hook is the same as the\n\
2817 @code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes\n\
2818 explicit named address space support.",
2819 bool, (enum machine_mode mode, rtx exp, bool strict, addr_space_t as),
2820 default_addr_space_legitimate_address_p)
2822 /* Return an updated address to convert an invalid pointer to a named
2823 address space to a valid one. If NULL_RTX is returned use machine
2824 independent methods to make the address valid. */
2825 DEFHOOK
2826 (legitimize_address,
2827 "Define this to modify an invalid address @var{x} to be a valid address\n\
2828 with mode @var{mode} in the named address space @var{as}. This target\n\
2829 hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,\n\
2830 except that it includes explicit named address space support.",
2831 rtx, (rtx x, rtx oldx, enum machine_mode mode, addr_space_t as),
2832 default_addr_space_legitimize_address)
2834 /* True if one named address space is a subset of another named address. */
2835 DEFHOOK
2836 (subset_p,
2837 "Define this to return whether the @var{subset} named address space is\n\
2838 contained within the @var{superset} named address space. Pointers to\n\
2839 a named address space that is a subset of another named address space\n\
2840 will be converted automatically without a cast if used together in\n\
2841 arithmetic operations. Pointers to a superset address space can be\n\
2842 converted to pointers to a subset address space via explicit casts.",
2843 bool, (addr_space_t subset, addr_space_t superset),
2844 default_addr_space_subset_p)
2846 /* Function to convert an rtl expression from one address space to another. */
2847 DEFHOOK
2848 (convert,
2849 "Define this to convert the pointer expression represented by the RTL\n\
2850 @var{op} with type @var{from_type} that points to a named address\n\
2851 space to a new pointer expression with type @var{to_type} that points\n\
2852 to a different named address space. When this hook it called, it is\n\
2853 guaranteed that one of the two address spaces is a subset of the other,\n\
2854 as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.",
2855 rtx, (rtx op, tree from_type, tree to_type),
2856 default_addr_space_convert)
2858 HOOK_VECTOR_END (addr_space)
2860 #undef HOOK_PREFIX
2861 #define HOOK_PREFIX "TARGET_"
2863 /* True if MODE is valid for the target. By "valid", we mean able to
2864 be manipulated in non-trivial ways. In particular, this means all
2865 the arithmetic is supported. */
2866 DEFHOOK
2867 (scalar_mode_supported_p,
2868 "Define this to return nonzero if the port is prepared to handle\n\
2869 insns involving scalar mode @var{mode}. For a scalar mode to be\n\
2870 considered supported, all the basic arithmetic and comparisons\n\
2871 must work.\n\
2873 The default version of this hook returns true for any mode\n\
2874 required to handle the basic C types (as defined by the port).\n\
2875 Included here are the double-word arithmetic supported by the\n\
2876 code in @file{optabs.c}.",
2877 bool, (enum machine_mode mode),
2878 default_scalar_mode_supported_p)
2880 /* Similarly for vector modes. "Supported" here is less strict. At
2881 least some operations are supported; need to check optabs or builtins
2882 for further details. */
2883 DEFHOOK
2884 (vector_mode_supported_p,
2885 "Define this to return nonzero if the port is prepared to handle\n\
2886 insns involving vector mode @var{mode}. At the very least, it\n\
2887 must have move patterns for this mode.",
2888 bool, (enum machine_mode mode),
2889 hook_bool_mode_false)
2891 DEFHOOK
2892 (vector_alignment,
2893 "This hook can be used to define the alignment for a vector of type\n\
2894 @var{type}, in order to comply with a platform ABI. The default is to\n\
2895 require natural alignment for vector types. The alignment returned by\n\
2896 this hook must be a power-of-two multiple of the default alignment of\n\
2897 the vector element type.",
2898 HOST_WIDE_INT, (const_tree type),
2899 default_vector_alignment)
2901 /* True if we should try to use a scalar mode to represent an array,
2902 overriding the usual MAX_FIXED_MODE limit. */
2903 DEFHOOK
2904 (array_mode_supported_p,
2905 "Return true if GCC should try to use a scalar mode to store an array\n\
2906 of @var{nelems} elements, given that each element has mode @var{mode}.\n\
2907 Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
2908 and allows GCC to use any defined integer mode.\n\
2910 One use of this hook is to support vector load and store operations\n\
2911 that operate on several homogeneous vectors. For example, ARM NEON\n\
2912 has operations like:\n\
2914 @smallexample\n\
2915 int8x8x3_t vld3_s8 (const int8_t *)\n\
2916 @end smallexample\n\
2918 where the return type is defined as:\n\
2920 @smallexample\n\
2921 typedef struct int8x8x3_t\n\
2922 @{\n\
2923 int8x8_t val[3];\n\
2924 @} int8x8x3_t;\n\
2925 @end smallexample\n\
2927 If this hook allows @code{val} to have a scalar mode, then\n\
2928 @code{int8x8x3_t} can have the same mode. GCC can then store\n\
2929 @code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
2930 bool, (enum machine_mode mode, unsigned HOST_WIDE_INT nelems),
2931 hook_bool_mode_uhwi_false)
2933 /* Compute cost of moving data from a register of class FROM to one of
2934 TO, using MODE. */
2935 DEFHOOK
2936 (register_move_cost,
2937 "This target hook should return the cost of moving data of mode @var{mode}\n\
2938 from a register in class @var{from} to one in class @var{to}. The classes\n\
2939 are expressed using the enumeration values such as @code{GENERAL_REGS}.\n\
2940 A value of 2 is the default; other values are interpreted relative to\n\
2941 that.\n\
2943 It is not required that the cost always equal 2 when @var{from} is the\n\
2944 same as @var{to}; on some machines it is expensive to move between\n\
2945 registers if they are not general registers.\n\
2947 If reload sees an insn consisting of a single @code{set} between two\n\
2948 hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their\n\
2949 classes returns a value of 2, reload does not check to ensure that the\n\
2950 constraints of the insn are met. Setting a cost of other than 2 will\n\
2951 allow reload to verify that the constraints are met. You should do this\n\
2952 if the @samp{mov@var{m}} pattern's constraints do not allow such copying.\n\
2954 The default version of this function returns 2.",
2955 int, (enum machine_mode mode, reg_class_t from, reg_class_t to),
2956 default_register_move_cost)
2958 /* Compute cost of moving registers to/from memory. */
2959 /* ??? Documenting the argument types for this hook requires a GFDL
2960 license grant. Also, the documentation uses a different name for RCLASS. */
2961 DEFHOOK
2962 (memory_move_cost,
2963 "This target hook should return the cost of moving data of mode @var{mode}\n\
2964 between a register of class @var{rclass} and memory; @var{in} is @code{false}\n\
2965 if the value is to be written to memory, @code{true} if it is to be read in.\n\
2966 This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.\n\
2967 If moving between registers and memory is more expensive than between two\n\
2968 registers, you should add this target hook to express the relative cost.\n\
2970 If you do not add this target hook, GCC uses a default cost of 4 plus\n\
2971 the cost of copying via a secondary reload register, if one is\n\
2972 needed. If your machine requires a secondary reload register to copy\n\
2973 between memory and a register of @var{rclass} but the reload mechanism is\n\
2974 more complex than copying via an intermediate, use this target hook to\n\
2975 reflect the actual cost of the move.\n\
2977 GCC defines the function @code{memory_move_secondary_cost} if\n\
2978 secondary reloads are needed. It computes the costs due to copying via\n\
2979 a secondary register. If your machine copies from memory using a\n\
2980 secondary register in the conventional way but the default base value of\n\
2981 4 is not correct for your machine, use this target hook to add some other\n\
2982 value to the result of that function. The arguments to that function\n\
2983 are the same as to this target hook.",
2984 int, (enum machine_mode mode, reg_class_t rclass, bool in),
2985 default_memory_move_cost)
2987 /* True for MODE if the target expects that registers in this mode will
2988 be allocated to registers in a small register class. The compiler is
2989 allowed to use registers explicitly used in the rtl as spill registers
2990 but it should prevent extending the lifetime of these registers. */
2991 DEFHOOK
2992 (small_register_classes_for_mode_p,
2993 "Define this to return nonzero for machine modes for which the port has\n\
2994 small register classes. If this target hook returns nonzero for a given\n\
2995 @var{mode}, the compiler will try to minimize the lifetime of registers\n\
2996 in @var{mode}. The hook may be called with @code{VOIDmode} as argument.\n\
2997 In this case, the hook is expected to return nonzero if it returns nonzero\n\
2998 for any mode.\n\
3000 On some machines, it is risky to let hard registers live across arbitrary\n\
3001 insns. Typically, these machines have instructions that require values\n\
3002 to be in specific registers (like an accumulator), and reload will fail\n\
3003 if the required hard register is used for another purpose across such an\n\
3004 insn.\n\
3006 Passes before reload do not know which hard registers will be used\n\
3007 in an instruction, but the machine modes of the registers set or used in\n\
3008 the instruction are already known. And for some machines, register\n\
3009 classes are small for, say, integer registers but not for floating point\n\
3010 registers. For example, the AMD x86-64 architecture requires specific\n\
3011 registers for the legacy x86 integer instructions, but there are many\n\
3012 SSE registers for floating point operations. On such targets, a good\n\
3013 strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}\n\
3014 machine modes but zero for the SSE register classes.\n\
3016 The default version of this hook returns false for any mode. It is always\n\
3017 safe to redefine this hook to return with a nonzero value. But if you\n\
3018 unnecessarily define it, you will reduce the amount of optimizations\n\
3019 that can be performed in some cases. If you do not define this hook\n\
3020 to return a nonzero value when it is required, the compiler will run out\n\
3021 of spill registers and print a fatal error message.",
3022 bool, (enum machine_mode mode),
3023 hook_bool_mode_false)
3025 /* Register number for a flags register. Only needs to be defined if the
3026 target is constrainted to use post-reload comparison elimination. */
3027 DEFHOOKPOD
3028 (flags_regnum,
3029 "If the target has a dedicated flags register, and it needs to use the\
3030 post-reload comparison elimination pass, then this value should be set\
3031 appropriately.",
3032 unsigned int, INVALID_REGNUM)
3034 /* Compute a (partial) cost for rtx X. Return true if the complete
3035 cost has been computed, and false if subexpressions should be
3036 scanned. In either case, *TOTAL contains the cost result. */
3037 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
3038 not necessarily defined at this point. */
3039 DEFHOOK
3040 (rtx_costs,
3041 "This target hook describes the relative costs of RTL expressions.\n\
3043 The cost may depend on the precise form of the expression, which is\n\
3044 available for examination in @var{x}, and the fact that @var{x} appears\n\
3045 as operand @var{opno} of an expression with rtx code @var{outer_code}.\n\
3046 That is, the hook can assume that there is some rtx @var{y} such\n\
3047 that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that\n\
3048 either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or\n\
3049 (b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.\n\
3051 @var{code} is @var{x}'s expression code---redundant, since it can be\n\
3052 obtained with @code{GET_CODE (@var{x})}.\n\
3054 In implementing this hook, you can use the construct\n\
3055 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3056 instructions.\n\
3058 On entry to the hook, @code{*@var{total}} contains a default estimate\n\
3059 for the cost of the expression. The hook should modify this value as\n\
3060 necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}\n\
3061 for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus\n\
3062 operations, and @code{COSTS_N_INSNS (1)} for all other operations.\n\
3064 When optimizing for code size, i.e.@: when @code{speed} is\n\
3065 false, this target hook should be used to estimate the relative\n\
3066 size cost of an expression, again relative to @code{COSTS_N_INSNS}.\n\
3068 The hook returns true when all subexpressions of @var{x} have been\n\
3069 processed, and false when @code{rtx_cost} should recurse.",
3070 bool, (rtx x, int code, int outer_code, int opno, int *total, bool speed),
3071 hook_bool_rtx_int_int_int_intp_bool_false)
3073 /* Compute the cost of X, used as an address. Never called with
3074 invalid addresses. */
3075 DEFHOOK
3076 (address_cost,
3077 "This hook computes the cost of an addressing mode that contains\n\
3078 @var{address}. If not defined, the cost is computed from\n\
3079 the @var{address} expression and the @code{TARGET_RTX_COST} hook.\n\
3081 For most CISC machines, the default cost is a good approximation of the\n\
3082 true cost of the addressing mode. However, on RISC machines, all\n\
3083 instructions normally have the same length and execution time. Hence\n\
3084 all addresses will have equal costs.\n\
3086 In cases where more than one form of an address is known, the form with\n\
3087 the lowest cost will be used. If multiple forms have the same, lowest,\n\
3088 cost, the one that is the most complex will be used.\n\
3090 For example, suppose an address that is equal to the sum of a register\n\
3091 and a constant is used twice in the same basic block. When this macro\n\
3092 is not defined, the address will be computed in a register and memory\n\
3093 references will be indirect through that register. On machines where\n\
3094 the cost of the addressing mode containing the sum is no higher than\n\
3095 that of a simple indirect reference, this will produce an additional\n\
3096 instruction and possibly require an additional register. Proper\n\
3097 specification of this macro eliminates this overhead for such machines.\n\
3099 This hook is never called with an invalid address.\n\
3101 On machines where an address involving more than one register is as\n\
3102 cheap as an address computation involving only one register, defining\n\
3103 @code{TARGET_ADDRESS_COST} to reflect this can cause two registers to\n\
3104 be live over a region of code where only one would have been if\n\
3105 @code{TARGET_ADDRESS_COST} were not defined in that manner. This effect\n\
3106 should be considered in the definition of this macro. Equivalent costs\n\
3107 should probably only be given to addresses with different numbers of\n\
3108 registers on machines with lots of registers.",
3109 int, (rtx address, enum machine_mode mode, addr_space_t as, bool speed),
3110 default_address_cost)
3112 /* Return where to allocate pseudo for a given hard register initial value. */
3113 DEFHOOK
3114 (allocate_initial_value,
3115 "\n\
3116 When the initial value of a hard register has been copied in a pseudo\n\
3117 register, it is often not necessary to actually allocate another register\n\
3118 to this pseudo register, because the original hard register or a stack slot\n\
3119 it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}\n\
3120 is called at the start of register allocation once for each hard register\n\
3121 that had its initial value copied by using\n\
3122 @code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.\n\
3123 Possible values are @code{NULL_RTX}, if you don't want\n\
3124 to do any special allocation, a @code{REG} rtx---that would typically be\n\
3125 the hard register itself, if it is known not to be clobbered---or a\n\
3126 @code{MEM}.\n\
3127 If you are returning a @code{MEM}, this is only a hint for the allocator;\n\
3128 it might decide to use another register anyways.\n\
3129 You may use @code{current_function_is_leaf} or \n\
3130 @code{REG_N_SETS} in the hook to determine if the hard\n\
3131 register in question will not be clobbered.\n\
3132 The default value of this hook is @code{NULL}, which disables any special\n\
3133 allocation.",
3134 rtx, (rtx hard_reg), NULL)
3136 /* Return nonzero if evaluating UNSPEC X might cause a trap.
3137 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
3138 DEFHOOK
3139 (unspec_may_trap_p,
3140 "This target hook returns nonzero if @var{x}, an @code{unspec} or\n\
3141 @code{unspec_volatile} operation, might cause a trap. Targets can use\n\
3142 this hook to enhance precision of analysis for @code{unspec} and\n\
3143 @code{unspec_volatile} operations. You may call @code{may_trap_p_1}\n\
3144 to analyze inner elements of @var{x} in which case @var{flags} should be\n\
3145 passed along.",
3146 int, (const_rtx x, unsigned flags),
3147 default_unspec_may_trap_p)
3149 /* Given a register, this hook should return a parallel of registers
3150 to represent where to find the register pieces. Define this hook
3151 if the register and its mode are represented in Dwarf in
3152 non-contiguous locations, or if the register should be
3153 represented in more than one register in Dwarf. Otherwise, this
3154 hook should return NULL_RTX. */
3155 DEFHOOK
3156 (dwarf_register_span,
3157 "Given a register, this hook should return a parallel of registers to\n\
3158 represent where to find the register pieces. Define this hook if the\n\
3159 register and its mode are represented in Dwarf in non-contiguous\n\
3160 locations, or if the register should be represented in more than one\n\
3161 register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.\n\
3162 If not defined, the default is to return @code{NULL_RTX}.",
3163 rtx, (rtx reg),
3164 hook_rtx_rtx_null)
3166 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
3167 entries not corresponding directly to registers below
3168 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
3169 code, given the address of the table. */
3170 DEFHOOK
3171 (init_dwarf_reg_sizes_extra,
3172 "If some registers are represented in Dwarf-2 unwind information in\n\
3173 multiple pieces, define this hook to fill in information about the\n\
3174 sizes of those pieces in the table used by the unwinder at runtime.\n\
3175 It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after\n\
3176 filling in a single size corresponding to each hard register;\n\
3177 @var{address} is the address of the table.",
3178 void, (tree address),
3179 hook_void_tree)
3181 /* Fetch the fixed register(s) which hold condition codes, for
3182 targets where it makes sense to look for duplicate assignments to
3183 the condition codes. This should return true if there is such a
3184 register, false otherwise. The arguments should be set to the
3185 fixed register numbers. Up to two condition code registers are
3186 supported. If there is only one for this target, the int pointed
3187 at by the second argument should be set to -1. */
3188 DEFHOOK
3189 (fixed_condition_code_regs,
3190 "On targets which do not use @code{(cc0)}, and which use a hard\n\
3191 register rather than a pseudo-register to hold condition codes, the\n\
3192 regular CSE passes are often not able to identify cases in which the\n\
3193 hard register is set to a common value. Use this hook to enable a\n\
3194 small pass which optimizes such cases. This hook should return true\n\
3195 to enable this pass, and it should set the integers to which its\n\
3196 arguments point to the hard register numbers used for condition codes.\n\
3197 When there is only one such register, as is true on most systems, the\n\
3198 integer pointed to by @var{p2} should be set to\n\
3199 @code{INVALID_REGNUM}.\n\
3201 The default version of this hook returns false.",
3202 bool, (unsigned int *p1, unsigned int *p2),
3203 hook_bool_uintp_uintp_false)
3205 /* If two condition code modes are compatible, return a condition
3206 code mode which is compatible with both, such that a comparison
3207 done in the returned mode will work for both of the original
3208 modes. If the condition code modes are not compatible, return
3209 VOIDmode. */
3210 DEFHOOK
3211 (cc_modes_compatible,
3212 "On targets which use multiple condition code modes in class\n\
3213 @code{MODE_CC}, it is sometimes the case that a comparison can be\n\
3214 validly done in more than one mode. On such a system, define this\n\
3215 target hook to take two mode arguments and to return a mode in which\n\
3216 both comparisons may be validly done. If there is no such mode,\n\
3217 return @code{VOIDmode}.\n\
3219 The default version of this hook checks whether the modes are the\n\
3220 same. If they are, it returns that mode. If they are different, it\n\
3221 returns @code{VOIDmode}.",
3222 enum machine_mode, (enum machine_mode m1, enum machine_mode m2),
3223 default_cc_modes_compatible)
3225 /* Do machine-dependent code transformations. Called just before
3226 delayed-branch scheduling. */
3227 DEFHOOK
3228 (machine_dependent_reorg,
3229 "If non-null, this hook performs a target-specific pass over the\n\
3230 instruction stream. The compiler will run it at all optimization levels,\n\
3231 just before the point at which it normally does delayed-branch scheduling.\n\
3233 The exact purpose of the hook varies from target to target. Some use\n\
3234 it to do transformations that are necessary for correctness, such as\n\
3235 laying out in-function constant pools or avoiding hardware hazards.\n\
3236 Others use it as an opportunity to do some machine-dependent optimizations.\n\
3238 You need not implement the hook if it has nothing to do. The default\n\
3239 definition is null.",
3240 void, (void), NULL)
3242 /* Create the __builtin_va_list type. */
3243 DEFHOOK
3244 (build_builtin_va_list,
3245 "This hook returns a type node for @code{va_list} for the target.\n\
3246 The default version of the hook returns @code{void*}.",
3247 tree, (void),
3248 std_build_builtin_va_list)
3250 /* Enumerate the va list variants. */
3251 DEFHOOK
3252 (enum_va_list_p,
3253 "This target hook is used in function @code{c_common_nodes_and_builtins}\n\
3254 to iterate through the target specific builtin types for va_list. The\n\
3255 variable @var{idx} is used as iterator. @var{pname} has to be a pointer\n\
3256 to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed\n\
3257 variable.\n\
3258 The arguments @var{pname} and @var{ptree} are used to store the result of\n\
3259 this macro and are set to the name of the va_list builtin type and its\n\
3260 internal type.\n\
3261 If the return value of this macro is zero, then there is no more element.\n\
3262 Otherwise the @var{IDX} should be increased for the next call of this\n\
3263 macro to iterate through all types.",
3264 int, (int idx, const char **pname, tree *ptree),
3265 NULL)
3267 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
3268 DEFHOOK
3269 (fn_abi_va_list,
3270 "This hook returns the va_list type of the calling convention specified by\n\
3271 @var{fndecl}.\n\
3272 The default version of this hook returns @code{va_list_type_node}.",
3273 tree, (tree fndecl),
3274 std_fn_abi_va_list)
3276 /* Get the __builtin_va_list type dependent on input type. */
3277 DEFHOOK
3278 (canonical_va_list_type,
3279 "This hook returns the va_list type of the calling convention specified by the\n\
3280 type of @var{type}. If @var{type} is not a valid va_list type, it returns\n\
3281 @code{NULL_TREE}.",
3282 tree, (tree type),
3283 std_canonical_va_list_type)
3285 /* ??? Documenting this hook requires a GFDL license grant. */
3286 DEFHOOK_UNDOC
3287 (expand_builtin_va_start,
3288 "Expand the @code{__builtin_va_start} builtin.",
3289 void, (tree valist, rtx nextarg), NULL)
3291 /* Gimplifies a VA_ARG_EXPR. */
3292 DEFHOOK
3293 (gimplify_va_arg_expr,
3294 "This hook performs target-specific gimplification of\n\
3295 @code{VA_ARG_EXPR}. The first two parameters correspond to the\n\
3296 arguments to @code{va_arg}; the latter two are as in\n\
3297 @code{gimplify.c:gimplify_expr}.",
3298 tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
3299 std_gimplify_va_arg_expr)
3301 /* Validity-checking routines for PCH files, target-specific.
3302 get_pch_validity returns a pointer to the data to be stored,
3303 and stores the size in its argument. pch_valid_p gets the same
3304 information back and returns NULL if the PCH is valid,
3305 or an error message if not. */
3306 DEFHOOK
3307 (get_pch_validity,
3308 "This hook returns a pointer to the data needed by\n\
3309 @code{TARGET_PCH_VALID_P} and sets\n\
3310 @samp{*@var{sz}} to the size of the data in bytes.",
3311 void *, (size_t *sz),
3312 default_get_pch_validity)
3314 DEFHOOK
3315 (pch_valid_p,
3316 "This hook checks whether the options used to create a PCH file are\n\
3317 compatible with the current settings. It returns @code{NULL}\n\
3318 if so and a suitable error message if not. Error messages will\n\
3319 be presented to the user and must be localized using @samp{_(@var{msg})}.\n\
3321 @var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}\n\
3322 when the PCH file was created and @var{sz} is the size of that data in bytes.\n\
3323 It's safe to assume that the data was created by the same version of the\n\
3324 compiler, so no format checking is needed.\n\
3326 The default definition of @code{default_pch_valid_p} should be\n\
3327 suitable for most targets.",
3328 const char *, (const void *data, size_t sz),
3329 default_pch_valid_p)
3331 DEFHOOK
3332 (prepare_pch_save,
3333 "Called before writing out a PCH file. If the target has some\n\
3334 garbage-collected data that needs to be in a particular state on PCH loads,\n\
3335 it can use this hook to enforce that state. Very few targets need\n\
3336 to do anything here.",
3337 void, (void),
3338 hook_void_void)
3340 /* If nonnull, this function checks whether a PCH file with the
3341 given set of target flags can be used. It returns NULL if so,
3342 otherwise it returns an error message. */
3343 DEFHOOK
3344 (check_pch_target_flags,
3345 "If this hook is nonnull, the default implementation of\n\
3346 @code{TARGET_PCH_VALID_P} will use it to check for compatible values\n\
3347 of @code{target_flags}. @var{pch_flags} specifies the value that\n\
3348 @code{target_flags} had when the PCH file was created. The return\n\
3349 value is the same as for @code{TARGET_PCH_VALID_P}.",
3350 const char *, (int pch_flags), NULL)
3352 /* True if the compiler should give an enum type only as many
3353 bytes as it takes to represent the range of possible values of
3354 that type. */
3355 DEFHOOK
3356 (default_short_enums,
3357 "This target hook should return true if the compiler should give an\n\
3358 @code{enum} type only as many bytes as it takes to represent the range\n\
3359 of possible values of that type. It should return false if all\n\
3360 @code{enum} types should be allocated like @code{int}.\n\
3362 The default is to return false.",
3363 bool, (void),
3364 hook_bool_void_false)
3366 /* This target hook returns an rtx that is used to store the address
3367 of the current frame into the built-in setjmp buffer. */
3368 DEFHOOK
3369 (builtin_setjmp_frame_value,
3370 "This target hook should return an rtx that is used to store\n\
3371 the address of the current frame into the built in @code{setjmp} buffer.\n\
3372 The default value, @code{virtual_stack_vars_rtx}, is correct for most\n\
3373 machines. One reason you may need to define this target hook is if\n\
3374 @code{hard_frame_pointer_rtx} is the appropriate value on your machine.",
3375 rtx, (void),
3376 default_builtin_setjmp_frame_value)
3378 /* This target hook should add STRING_CST trees for any hard regs
3379 the port wishes to automatically clobber for an asm. */
3380 DEFHOOK
3381 (md_asm_clobbers,
3382 "This target hook should add to @var{clobbers} @code{STRING_CST} trees for\n\
3383 any hard regs the port wishes to automatically clobber for an asm.\n\
3384 It should return the result of the last @code{tree_cons} used to add a\n\
3385 clobber. The @var{outputs}, @var{inputs} and @var{clobber} lists are the\n\
3386 corresponding parameters to the asm and may be inspected to avoid\n\
3387 clobbering a register that is an input or output of the asm. You can use\n\
3388 @code{tree_overlaps_hard_reg_set}, declared in @file{tree.h}, to test\n\
3389 for overlap with regards to asm-declared registers.",
3390 tree, (tree outputs, tree inputs, tree clobbers),
3391 hook_tree_tree_tree_tree_3rd_identity)
3393 /* This target hook allows the backend to specify a calling convention
3394 in the debug information. This function actually returns an
3395 enum dwarf_calling_convention, but because of forward declarations
3396 and not wanting to include dwarf2.h everywhere target.h is included
3397 the function is being declared as an int. */
3398 DEFHOOK
3399 (dwarf_calling_convention,
3400 "Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to\n\
3401 be emitted for each function. Instead of an integer return the enum\n\
3402 value for the @code{DW_CC_} tag.",
3403 int, (const_tree function),
3404 hook_int_const_tree_0)
3406 /* This target hook allows the backend to emit frame-related insns that
3407 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
3408 engine will invoke it on insns of the form
3409 (set (reg) (unspec [...] UNSPEC_INDEX))
3411 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
3412 to let the backend emit the call frame instructions. */
3413 DEFHOOK
3414 (dwarf_handle_frame_unspec,
3415 "This target hook allows the backend to emit frame-related insns that\n\
3416 contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging\n\
3417 info engine will invoke it on insns of the form\n\
3418 @smallexample\n\
3419 (set (reg) (unspec [@dots{}] UNSPEC_INDEX))\n\
3420 @end smallexample\n\
3421 and\n\
3422 @smallexample\n\
3423 (set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).\n\
3424 @end smallexample\n\
3425 to let the backend emit the call frame instructions. @var{label} is\n\
3426 the CFI label attached to the insn, @var{pattern} is the pattern of\n\
3427 the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.",
3428 void, (const char *label, rtx pattern, int index), NULL)
3430 /* ??? Documenting this hook requires a GFDL license grant. */
3431 DEFHOOK_UNDOC
3432 (stdarg_optimize_hook,
3433 "Perform architecture specific checking of statements gimplified\
3434 from @code{VA_ARG_EXPR}. @var{stmt} is the statement. Returns true if\
3435 the statement doesn't need to be checked for @code{va_list} references.",
3436 bool, (struct stdarg_info *ai, const_gimple stmt), NULL)
3438 /* This target hook allows the operating system to override the DECL
3439 that represents the external variable that contains the stack
3440 protection guard variable. The type of this DECL is ptr_type_node. */
3441 DEFHOOK
3442 (stack_protect_guard,
3443 "This hook returns a @code{DECL} node for the external variable to use\n\
3444 for the stack protection guard. This variable is initialized by the\n\
3445 runtime to some random value and is used to initialize the guard value\n\
3446 that is placed at the top of the local stack frame. The type of this\n\
3447 variable must be @code{ptr_type_node}.\n\
3449 The default version of this hook creates a variable called\n\
3450 @samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.",
3451 tree, (void),
3452 default_stack_protect_guard)
3454 /* This target hook allows the operating system to override the CALL_EXPR
3455 that is invoked when a check vs the guard variable fails. */
3456 DEFHOOK
3457 (stack_protect_fail,
3458 "This hook returns a @code{CALL_EXPR} that alerts the runtime that the\n\
3459 stack protect guard variable has been modified. This expression should\n\
3460 involve a call to a @code{noreturn} function.\n\
3462 The default version of this hook invokes a function called\n\
3463 @samp{__stack_chk_fail}, taking no arguments. This function is\n\
3464 normally defined in @file{libgcc2.c}.",
3465 tree, (void),
3466 default_external_stack_protect_fail)
3468 /* Returns NULL if target supports the insn within a doloop block,
3469 otherwise it returns an error message. */
3470 DEFHOOK
3471 (invalid_within_doloop,
3472 "\n\
3473 Take an instruction in @var{insn} and return NULL if it is valid within a\n\
3474 low-overhead loop, otherwise return a string explaining why doloop\n\
3475 could not be applied.\n\
3477 Many targets use special registers for low-overhead looping. For any\n\
3478 instruction that clobbers these this function should return a string indicating\n\
3479 the reason why the doloop could not be applied.\n\
3480 By default, the RTL loop optimizer does not use a present doloop pattern for\n\
3481 loops containing function calls or branch on table instructions.",
3482 const char *, (const_rtx insn),
3483 default_invalid_within_doloop)
3485 /* Returns true for a legitimate combined insn. */
3486 DEFHOOK
3487 (legitimate_combined_insn,
3488 "Take an instruction in @var{insn} and return @code{false} if the instruction\
3489 is not appropriate as a combination of two or more instructions. The\
3490 default is to accept all instructions.",
3491 bool, (rtx insn),
3492 hook_bool_rtx_true)
3494 DEFHOOK
3495 (valid_dllimport_attribute_p,
3496 "@var{decl} is a variable or function with @code{__attribute__((dllimport))}\
3497 specified. Use this hook if the target needs to add extra validation\
3498 checks to @code{handle_dll_attribute}.",
3499 bool, (const_tree decl),
3500 hook_bool_const_tree_true)
3502 /* If non-zero, align constant anchors in CSE to a multiple of this
3503 value. */
3504 DEFHOOKPOD
3505 (const_anchor,
3506 "On some architectures it can take multiple instructions to synthesize\n\
3507 a constant. If there is another constant already in a register that\n\
3508 is close enough in value then it is preferable that the new constant\n\
3509 is computed from this register using immediate addition or\n\
3510 subtraction. We accomplish this through CSE. Besides the value of\n\
3511 the constant we also add a lower and an upper constant anchor to the\n\
3512 available expressions. These are then queried when encountering new\n\
3513 constants. The anchors are computed by rounding the constant up and\n\
3514 down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.\n\
3515 @code{TARGET_CONST_ANCHOR} should be the maximum positive value\n\
3516 accepted by immediate-add plus one. We currently assume that the\n\
3517 value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on\n\
3518 MIPS, where add-immediate takes a 16-bit signed value,\n\
3519 @code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value\n\
3520 is zero, which disables this optimization.",
3521 unsigned HOST_WIDE_INT, 0)
3523 /* Defines, which target-dependent bits (upper 16) are used by port */
3524 DEFHOOK
3525 (memmodel_check,
3526 "Validate target specific memory model mask bits. When NULL no target specific\n\
3527 memory model bits are allowed.",
3528 unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)
3530 /* Defines an offset bitwise ored into shifted address to get corresponding
3531 Address Sanitizer shadow address, or -1 if Address Sanitizer is not
3532 supported by the target. */
3533 DEFHOOK
3534 (asan_shadow_offset,
3535 "Return the offset bitwise ored into shifted address to get corresponding\n\
3536 Address Sanitizer shadow memory address. NULL if Address Sanitizer is not\n\
3537 supported by the target.",
3538 unsigned HOST_WIDE_INT, (void),
3539 NULL)
3541 /* Functions relating to calls - argument passing, returns, etc. */
3542 /* Members of struct call have no special macro prefix. */
3543 HOOK_VECTOR (TARGET_CALLS, calls)
3545 DEFHOOK
3546 (promote_function_mode,
3547 "Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or\n\
3548 function return values. The target hook should return the new mode\n\
3549 and possibly change @code{*@var{punsignedp}} if the promotion should\n\
3550 change signedness. This function is called only for scalar @emph{or\n\
3551 pointer} types.\n\
3553 @var{for_return} allows to distinguish the promotion of arguments and\n\
3554 return values. If it is @code{1}, a return value is being promoted and\n\
3555 @code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.\n\
3556 If it is @code{2}, the returned mode should be that of the register in\n\
3557 which an incoming parameter is copied, or the outgoing result is computed;\n\
3558 then the hook should return the same mode as @code{promote_mode}, though\n\
3559 the signedness may be different.\n\
3561 @var{type} can be NULL when promoting function arguments of libcalls.\n\
3563 The default is to not promote arguments and return values. You can\n\
3564 also define the hook to @code{default_promote_function_mode_always_promote}\n\
3565 if you would like to apply the same rules given by @code{PROMOTE_MODE}.",
3566 enum machine_mode, (const_tree type, enum machine_mode mode, int *punsignedp,
3567 const_tree funtype, int for_return),
3568 default_promote_function_mode)
3570 DEFHOOK
3571 (promote_prototypes,
3572 "This target hook returns @code{true} if an argument declared in a\n\
3573 prototype as an integral type smaller than @code{int} should actually be\n\
3574 passed as an @code{int}. In addition to avoiding errors in certain\n\
3575 cases of mismatch, it also makes for better code on certain machines.\n\
3576 The default is to not promote prototypes.",
3577 bool, (const_tree fntype),
3578 hook_bool_const_tree_false)
3580 DEFHOOK
3581 (struct_value_rtx,
3582 "This target hook should return the location of the structure value\n\
3583 address (normally a @code{mem} or @code{reg}), or 0 if the address is\n\
3584 passed as an ``invisible'' first argument. Note that @var{fndecl} may\n\
3585 be @code{NULL}, for libcalls. You do not need to define this target\n\
3586 hook if the address is always passed as an ``invisible'' first\n\
3587 argument.\n\
3589 On some architectures the place where the structure value address\n\
3590 is found by the called function is not the same place that the\n\
3591 caller put it. This can be due to register windows, or it could\n\
3592 be because the function prologue moves it to a different place.\n\
3593 @var{incoming} is @code{1} or @code{2} when the location is needed in\n\
3594 the context of the called function, and @code{0} in the context of\n\
3595 the caller.\n\
3597 If @var{incoming} is nonzero and the address is to be found on the\n\
3598 stack, return a @code{mem} which refers to the frame pointer. If\n\
3599 @var{incoming} is @code{2}, the result is being used to fetch the\n\
3600 structure value address at the beginning of a function. If you need\n\
3601 to emit adjusting code, you should do it at this point.",
3602 rtx, (tree fndecl, int incoming),
3603 hook_rtx_tree_int_null)
3604 DEFHOOK
3605 (return_in_memory,
3606 "This target hook should return a nonzero value to say to return the\n\
3607 function value in memory, just as large structures are always returned.\n\
3608 Here @var{type} will be the data type of the value, and @var{fntype}\n\
3609 will be the type of the function doing the returning, or @code{NULL} for\n\
3610 libcalls.\n\
3612 Note that values of mode @code{BLKmode} must be explicitly handled\n\
3613 by this function. Also, the option @option{-fpcc-struct-return}\n\
3614 takes effect regardless of this macro. On most systems, it is\n\
3615 possible to leave the hook undefined; this causes a default\n\
3616 definition to be used, whose value is the constant 1 for @code{BLKmode}\n\
3617 values, and 0 otherwise.\n\
3619 Do not use this hook to indicate that structures and unions should always\n\
3620 be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}\n\
3621 to indicate this.",
3622 bool, (const_tree type, const_tree fntype),
3623 default_return_in_memory)
3625 DEFHOOK
3626 (return_in_msb,
3627 "This hook should return true if values of type @var{type} are returned\n\
3628 at the most significant end of a register (in other words, if they are\n\
3629 padded at the least significant end). You can assume that @var{type}\n\
3630 is returned in a register; the caller is required to check this.\n\
3632 Note that the register provided by @code{TARGET_FUNCTION_VALUE} must\n\
3633 be able to hold the complete return value. For example, if a 1-, 2-\n\
3634 or 3-byte structure is returned at the most significant end of a\n\
3635 4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an\n\
3636 @code{SImode} rtx.",
3637 bool, (const_tree type),
3638 hook_bool_const_tree_false)
3640 /* Return true if a parameter must be passed by reference. TYPE may
3641 be null if this is a libcall. CA may be null if this query is
3642 from __builtin_va_arg. */
3643 DEFHOOK
3644 (pass_by_reference,
3645 "This target hook should return @code{true} if an argument at the\n\
3646 position indicated by @var{cum} should be passed by reference. This\n\
3647 predicate is queried after target independent reasons for being\n\
3648 passed by reference, such as @code{TREE_ADDRESSABLE (type)}.\n\
3650 If the hook returns true, a copy of that argument is made in memory and a\n\
3651 pointer to the argument is passed instead of the argument itself.\n\
3652 The pointer is passed in whatever way is appropriate for passing a pointer\n\
3653 to that type.",
3654 bool,
3655 (cumulative_args_t cum, enum machine_mode mode, const_tree type, bool named),
3656 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
3658 DEFHOOK
3659 (expand_builtin_saveregs,
3660 "If defined, this hook produces the machine-specific code for a call to\n\
3661 @code{__builtin_saveregs}. This code will be moved to the very\n\
3662 beginning of the function, before any parameter access are made. The\n\
3663 return value of this function should be an RTX that contains the value\n\
3664 to use as the return of @code{__builtin_saveregs}.",
3665 rtx, (void),
3666 default_expand_builtin_saveregs)
3668 /* Returns pretend_argument_size. */
3669 DEFHOOK
3670 (setup_incoming_varargs,
3671 "This target hook offers an alternative to using\n\
3672 @code{__builtin_saveregs} and defining the hook\n\
3673 @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous\n\
3674 register arguments into the stack so that all the arguments appear to\n\
3675 have been passed consecutively on the stack. Once this is done, you can\n\
3676 use the standard implementation of varargs that works for machines that\n\
3677 pass all their arguments on the stack.\n\
3679 The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data\n\
3680 structure, containing the values that are obtained after processing the\n\
3681 named arguments. The arguments @var{mode} and @var{type} describe the\n\
3682 last named argument---its machine mode and its data type as a tree node.\n\
3684 The target hook should do two things: first, push onto the stack all the\n\
3685 argument registers @emph{not} used for the named arguments, and second,\n\
3686 store the size of the data thus pushed into the @code{int}-valued\n\
3687 variable pointed to by @var{pretend_args_size}. The value that you\n\
3688 store here will serve as additional offset for setting up the stack\n\
3689 frame.\n\
3691 Because you must generate code to push the anonymous arguments at\n\
3692 compile time without knowing their data types,\n\
3693 @code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that\n\
3694 have just a single category of argument register and use it uniformly\n\
3695 for all data types.\n\
3697 If the argument @var{second_time} is nonzero, it means that the\n\
3698 arguments of the function are being analyzed for the second time. This\n\
3699 happens for an inline function, which is not actually compiled until the\n\
3700 end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should\n\
3701 not generate any instructions in this case.",
3702 void, (cumulative_args_t args_so_far, enum machine_mode mode, tree type,
3703 int *pretend_args_size, int second_time),
3704 default_setup_incoming_varargs)
3706 DEFHOOK
3707 (strict_argument_naming,
3708 "Define this hook to return @code{true} if the location where a function\n\
3709 argument is passed depends on whether or not it is a named argument.\n\
3711 This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}\n\
3712 is set for varargs and stdarg functions. If this hook returns\n\
3713 @code{true}, the @var{named} argument is always true for named\n\
3714 arguments, and false for unnamed arguments. If it returns @code{false},\n\
3715 but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},\n\
3716 then all arguments are treated as named. Otherwise, all named arguments\n\
3717 except the last are treated as named.\n\
3719 You need not define this hook if it always returns @code{false}.",
3720 bool, (cumulative_args_t ca),
3721 hook_bool_CUMULATIVE_ARGS_false)
3723 /* Returns true if we should use
3724 targetm.calls.setup_incoming_varargs() and/or
3725 targetm.calls.strict_argument_naming(). */
3726 DEFHOOK
3727 (pretend_outgoing_varargs_named,
3728 "If you need to conditionally change ABIs so that one works with\n\
3729 @code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither\n\
3730 @code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was\n\
3731 defined, then define this hook to return @code{true} if\n\
3732 @code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.\n\
3733 Otherwise, you should not define this hook.",
3734 bool, (cumulative_args_t ca),
3735 default_pretend_outgoing_varargs_named)
3737 /* Given a complex type T, return true if a parameter of type T
3738 should be passed as two scalars. */
3739 DEFHOOK
3740 (split_complex_arg,
3741 "This hook should return true if parameter of type @var{type} are passed\n\
3742 as two scalar parameters. By default, GCC will attempt to pack complex\n\
3743 arguments into the target's word size. Some ABIs require complex arguments\n\
3744 to be split and treated as their individual components. For example, on\n\
3745 AIX64, complex floats should be passed in a pair of floating point\n\
3746 registers, even though a complex float would fit in one 64-bit floating\n\
3747 point register.\n\
3749 The default value of this hook is @code{NULL}, which is treated as always\n\
3750 false.",
3751 bool, (const_tree type), NULL)
3753 /* Return true if type T, mode MODE, may not be passed in registers,
3754 but must be passed on the stack. */
3755 /* ??? This predicate should be applied strictly after pass-by-reference.
3756 Need audit to verify that this is the case. */
3757 DEFHOOK
3758 (must_pass_in_stack,
3759 "This target hook should return @code{true} if we should not pass @var{type}\n\
3760 solely in registers. The file @file{expr.h} defines a\n\
3761 definition that is usually appropriate, refer to @file{expr.h} for additional\n\
3762 documentation.",
3763 bool, (enum machine_mode mode, const_tree type),
3764 must_pass_in_stack_var_size_or_pad)
3766 /* Return true if type TYPE, mode MODE, which is passed by reference,
3767 should have the object copy generated by the callee rather than
3768 the caller. It is never called for TYPE requiring constructors. */
3769 DEFHOOK
3770 (callee_copies,
3771 "The function argument described by the parameters to this hook is\n\
3772 known to be passed by reference. The hook should return true if the\n\
3773 function argument should be copied by the callee instead of copied\n\
3774 by the caller.\n\
3776 For any argument for which the hook returns true, if it can be\n\
3777 determined that the argument is not modified, then a copy need\n\
3778 not be generated.\n\
3780 The default version of this hook always returns false.",
3781 bool,
3782 (cumulative_args_t cum, enum machine_mode mode, const_tree type, bool named),
3783 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
3785 /* Return zero for arguments passed entirely on the stack or entirely
3786 in registers. If passed in both, return the number of bytes passed
3787 in registers; the balance is therefore passed on the stack. */
3788 DEFHOOK
3789 (arg_partial_bytes,
3790 "This target hook returns the number of bytes at the beginning of an\n\
3791 argument that must be put in registers. The value must be zero for\n\
3792 arguments that are passed entirely in registers or that are entirely\n\
3793 pushed on the stack.\n\
3795 On some machines, certain arguments must be passed partially in\n\
3796 registers and partially in memory. On these machines, typically the\n\
3797 first few words of arguments are passed in registers, and the rest\n\
3798 on the stack. If a multi-word argument (a @code{double} or a\n\
3799 structure) crosses that boundary, its first few words must be passed\n\
3800 in registers and the rest must be pushed. This macro tells the\n\
3801 compiler when this occurs, and how many bytes should go in registers.\n\
3803 @code{TARGET_FUNCTION_ARG} for these arguments should return the first\n\
3804 register to be used by the caller for this argument; likewise\n\
3805 @code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.",
3806 int, (cumulative_args_t cum, enum machine_mode mode, tree type, bool named),
3807 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0)
3809 /* Update the state in CA to advance past an argument in the
3810 argument list. The values MODE, TYPE, and NAMED describe that
3811 argument. */
3812 DEFHOOK
3813 (function_arg_advance,
3814 "This hook updates the summarizer variable pointed to by @var{ca} to\n\
3815 advance past an argument in the argument list. The values @var{mode},\n\
3816 @var{type} and @var{named} describe that argument. Once this is done,\n\
3817 the variable @var{cum} is suitable for analyzing the @emph{following}\n\
3818 argument with @code{TARGET_FUNCTION_ARG}, etc.\n\
3820 This hook need not do anything if the argument in question was passed\n\
3821 on the stack. The compiler knows how to track the amount of stack space\n\
3822 used for arguments without any special help.",
3823 void,
3824 (cumulative_args_t ca, enum machine_mode mode, const_tree type, bool named),
3825 default_function_arg_advance)
3827 /* Return zero if the argument described by the state of CA should
3828 be placed on a stack, or a hard register in which to store the
3829 argument. The values MODE, TYPE, and NAMED describe that
3830 argument. */
3831 DEFHOOK
3832 (function_arg,
3833 "Return an RTX indicating whether a function argument is passed in a\n\
3834 register and if so, which register.\n\
3836 The arguments are @var{ca}, which summarizes all the previous\n\
3837 arguments; @var{mode}, the machine mode of the argument; @var{type},\n\
3838 the data type of the argument as a tree node or 0 if that is not known\n\
3839 (which happens for C support library functions); and @var{named},\n\
3840 which is @code{true} for an ordinary argument and @code{false} for\n\
3841 nameless arguments that correspond to @samp{@dots{}} in the called\n\
3842 function's prototype. @var{type} can be an incomplete type if a\n\
3843 syntax error has previously occurred.\n\
3845 The return value is usually either a @code{reg} RTX for the hard\n\
3846 register in which to pass the argument, or zero to pass the argument\n\
3847 on the stack.\n\
3849 The value of the expression can also be a @code{parallel} RTX@. This is\n\
3850 used when an argument is passed in multiple locations. The mode of the\n\
3851 @code{parallel} should be the mode of the entire argument. The\n\
3852 @code{parallel} holds any number of @code{expr_list} pairs; each one\n\
3853 describes where part of the argument is passed. In each\n\
3854 @code{expr_list} the first operand must be a @code{reg} RTX for the hard\n\
3855 register in which to pass this part of the argument, and the mode of the\n\
3856 register RTX indicates how large this part of the argument is. The\n\
3857 second operand of the @code{expr_list} is a @code{const_int} which gives\n\
3858 the offset in bytes into the entire argument of where this part starts.\n\
3859 As a special exception the first @code{expr_list} in the @code{parallel}\n\
3860 RTX may have a first operand of zero. This indicates that the entire\n\
3861 argument is also stored on the stack.\n\
3863 The last time this hook is called, it is called with @code{MODE ==\n\
3864 VOIDmode}, and its result is passed to the @code{call} or @code{call_value}\n\
3865 pattern as operands 2 and 3 respectively.\n\
3867 @cindex @file{stdarg.h} and register arguments\n\
3868 The usual way to make the ISO library @file{stdarg.h} work on a\n\
3869 machine where some arguments are usually passed in registers, is to\n\
3870 cause nameless arguments to be passed on the stack instead. This is\n\
3871 done by making @code{TARGET_FUNCTION_ARG} return 0 whenever\n\
3872 @var{named} is @code{false}.\n\
3874 @cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}\n\
3875 @cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}\n\
3876 You may use the hook @code{targetm.calls.must_pass_in_stack}\n\
3877 in the definition of this macro to determine if this argument is of a\n\
3878 type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}\n\
3879 is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an\n\
3880 argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is\n\
3881 defined, the argument will be computed in the stack and then loaded into\n\
3882 a register.",
3883 rtx, (cumulative_args_t ca, enum machine_mode mode, const_tree type,
3884 bool named),
3885 default_function_arg)
3887 /* Likewise, but for machines with register windows. Return the
3888 location where the argument will appear to the callee. */
3889 DEFHOOK
3890 (function_incoming_arg,
3891 "Define this hook if the target machine has ``register windows'', so\n\
3892 that the register in which a function sees an arguments is not\n\
3893 necessarily the same as the one in which the caller passed the\n\
3894 argument.\n\
3896 For such machines, @code{TARGET_FUNCTION_ARG} computes the register in\n\
3897 which the caller passes the value, and\n\
3898 @code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar\n\
3899 fashion to tell the function being called where the arguments will\n\
3900 arrive.\n\
3902 If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,\n\
3903 @code{TARGET_FUNCTION_ARG} serves both purposes.",
3904 rtx, (cumulative_args_t ca, enum machine_mode mode, const_tree type,
3905 bool named),
3906 default_function_incoming_arg)
3908 DEFHOOK
3909 (function_arg_boundary,
3910 "This hook returns the alignment boundary, in bits, of an argument\n\
3911 with the specified mode and type. The default hook returns\n\
3912 @code{PARM_BOUNDARY} for all arguments.",
3913 unsigned int, (enum machine_mode mode, const_tree type),
3914 default_function_arg_boundary)
3916 DEFHOOK
3917 (function_arg_round_boundary,
3918 "Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
3919 which is the default value for this hook. You can define this hook to\n\
3920 return a different value if an argument size must be rounded to a larger\n\
3921 value.",
3922 unsigned int, (enum machine_mode mode, const_tree type),
3923 default_function_arg_round_boundary)
3925 /* Return the diagnostic message string if function without a prototype
3926 is not allowed for this 'val' argument; NULL otherwise. */
3927 DEFHOOK
3928 (invalid_arg_for_unprototyped_fn,
3929 "If defined, this macro returns the diagnostic message when it is\n\
3930 illegal to pass argument @var{val} to function @var{funcdecl}\n\
3931 with prototype @var{typelist}.",
3932 const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
3933 hook_invalid_arg_for_unprototyped_fn)
3935 /* Return an rtx for the return value location of the function
3936 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
3937 DEFHOOK
3938 (function_value,
3939 "\n\
3940 Define this to return an RTX representing the place where a function\n\
3941 returns or receives a value of data type @var{ret_type}, a tree node\n\
3942 representing a data type. @var{fn_decl_or_type} is a tree node\n\
3943 representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a\n\
3944 function being called. If @var{outgoing} is false, the hook should\n\
3945 compute the register in which the caller will see the return value.\n\
3946 Otherwise, the hook should return an RTX representing the place where\n\
3947 a function returns a value.\n\
3949 On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.\n\
3950 (Actually, on most machines, scalar values are returned in the same\n\
3951 place regardless of mode.) The value of the expression is usually a\n\
3952 @code{reg} RTX for the hard register where the return value is stored.\n\
3953 The value can also be a @code{parallel} RTX, if the return value is in\n\
3954 multiple places. See @code{TARGET_FUNCTION_ARG} for an explanation of the\n\
3955 @code{parallel} form. Note that the callee will populate every\n\
3956 location specified in the @code{parallel}, but if the first element of\n\
3957 the @code{parallel} contains the whole return value, callers will use\n\
3958 that element as the canonical location and ignore the others. The m68k\n\
3959 port uses this type of @code{parallel} to return pointers in both\n\
3960 @samp{%a0} (the canonical location) and @samp{%d0}.\n\
3962 If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply\n\
3963 the same promotion rules specified in @code{PROMOTE_MODE} if\n\
3964 @var{valtype} is a scalar type.\n\
3966 If the precise function being called is known, @var{func} is a tree\n\
3967 node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null\n\
3968 pointer. This makes it possible to use a different value-returning\n\
3969 convention for specific functions when all their calls are\n\
3970 known.\n\
3972 Some target machines have ``register windows'' so that the register in\n\
3973 which a function returns its value is not the same as the one in which\n\
3974 the caller sees the value. For such machines, you should return\n\
3975 different RTX depending on @var{outgoing}.\n\
3977 @code{TARGET_FUNCTION_VALUE} is not used for return values with\n\
3978 aggregate data types, because these are returned in another way. See\n\
3979 @code{TARGET_STRUCT_VALUE_RTX} and related macros, below.",
3980 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
3981 default_function_value)
3983 /* Return the rtx for the result of a libcall of mode MODE,
3984 calling the function FN_NAME. */
3985 DEFHOOK
3986 (libcall_value,
3987 "Define this hook if the back-end needs to know the name of the libcall\n\
3988 function in order to determine where the result should be returned.\n\
3990 The mode of the result is given by @var{mode} and the name of the called\n\
3991 library function is given by @var{fun}. The hook should return an RTX\n\
3992 representing the place where the library function result will be returned.\n\
3994 If this hook is not defined, then LIBCALL_VALUE will be used.",
3995 rtx, (enum machine_mode mode, const_rtx fun),
3996 default_libcall_value)
3998 /* Return true if REGNO is a possible register number for
3999 a function value as seen by the caller. */
4000 DEFHOOK
4001 (function_value_regno_p,
4002 "A target hook that return @code{true} if @var{regno} is the number of a hard\n\
4003 register in which the values of called function may come back.\n\
4005 A register whose use for returning values is limited to serving as the\n\
4006 second of a pair (for a value of type @code{double}, say) need not be\n\
4007 recognized by this target hook.\n\
4009 If the machine has register windows, so that the caller and the called\n\
4010 function use different registers for the return value, this target hook\n\
4011 should recognize only the caller's register numbers.\n\
4013 If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.",
4014 bool, (const unsigned int regno),
4015 default_function_value_regno_p)
4017 /* ??? Documenting this hook requires a GFDL license grant. */
4018 DEFHOOK_UNDOC
4019 (internal_arg_pointer,
4020 "Return an rtx for the argument pointer incoming to the\
4021 current function.",
4022 rtx, (void),
4023 default_internal_arg_pointer)
4025 /* Update the current function stack boundary if needed. */
4026 DEFHOOK
4027 (update_stack_boundary,
4028 "Define this macro to update the current function stack boundary if\n\
4029 necessary.",
4030 void, (void), NULL)
4032 /* Handle stack alignment and return an rtx for Dynamic Realign
4033 Argument Pointer if necessary. */
4034 DEFHOOK
4035 (get_drap_rtx,
4036 "This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a\n\
4037 different argument pointer register is needed to access the function's\n\
4038 argument list due to stack realignment. Return @code{NULL} if no DRAP\n\
4039 is needed.",
4040 rtx, (void), NULL)
4042 /* Return true if all function parameters should be spilled to the
4043 stack. */
4044 DEFHOOK
4045 (allocate_stack_slots_for_args,
4046 "When optimization is disabled, this hook indicates whether or not\n\
4047 arguments should be allocated to stack slots. Normally, GCC allocates\n\
4048 stacks slots for arguments when not optimizing in order to make\n\
4049 debugging easier. However, when a function is declared with\n\
4050 @code{__attribute__((naked))}, there is no stack frame, and the compiler\n\
4051 cannot safely move arguments from the registers in which they are passed\n\
4052 to the stack. Therefore, this hook should return true in general, but\n\
4053 false for naked functions. The default implementation always returns true.",
4054 bool, (void),
4055 hook_bool_void_true)
4057 /* Return an rtx for the static chain for FNDECL. If INCOMING_P is true,
4058 then it should be for the callee; otherwise for the caller. */
4059 DEFHOOK
4060 (static_chain,
4061 "This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for\n\
4062 targets that may use different static chain locations for different\n\
4063 nested functions. This may be required if the target has function\n\
4064 attributes that affect the calling conventions of the function and\n\
4065 those calling conventions use different static chain locations.\n\
4067 The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.\n\
4069 If the static chain is passed in memory, this hook should be used to\n\
4070 provide rtx giving @code{mem} expressions that denote where they are stored.\n\
4071 Often the @code{mem} expression as seen by the caller will be at an offset\n\
4072 from the stack pointer and the @code{mem} expression as seen by the callee\n\
4073 will be at an offset from the frame pointer.\n\
4074 @findex stack_pointer_rtx\n\
4075 @findex frame_pointer_rtx\n\
4076 @findex arg_pointer_rtx\n\
4077 The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and\n\
4078 @code{arg_pointer_rtx} will have been initialized and should be used\n\
4079 to refer to those items.",
4080 rtx, (const_tree fndecl, bool incoming_p),
4081 default_static_chain)
4083 /* Fill in the trampoline at MEM with a call to FNDECL and a
4084 static chain value of CHAIN. */
4085 DEFHOOK
4086 (trampoline_init,
4087 "This hook is called to initialize a trampoline.\n\
4088 @var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}\n\
4089 is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an\n\
4090 RTX for the static chain value that should be passed to the function\n\
4091 when it is called.\n\
4093 If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the\n\
4094 first thing this hook should do is emit a block move into @var{m_tramp}\n\
4095 from the memory block returned by @code{assemble_trampoline_template}.\n\
4096 Note that the block move need only cover the constant parts of the\n\
4097 trampoline. If the target isolates the variable parts of the trampoline\n\
4098 to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.\n\
4100 If the target requires any other actions, such as flushing caches or\n\
4101 enabling stack execution, these actions should be performed after\n\
4102 initializing the trampoline proper.",
4103 void, (rtx m_tramp, tree fndecl, rtx static_chain),
4104 default_trampoline_init)
4106 /* Adjust the address of the trampoline in a target-specific way. */
4107 DEFHOOK
4108 (trampoline_adjust_address,
4109 "This hook should perform any machine-specific adjustment in\n\
4110 the address of the trampoline. Its argument contains the address of the\n\
4111 memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}. In case\n\
4112 the address to be used for a function call should be different from the\n\
4113 address at which the template was stored, the different address should\n\
4114 be returned; otherwise @var{addr} should be returned unchanged.\n\
4115 If this hook is not defined, @var{addr} will be used for function calls.",
4116 rtx, (rtx addr), NULL)
4118 /* Return the number of bytes of its own arguments that a function
4119 pops on returning, or 0 if the function pops no arguments and the
4120 caller must therefore pop them all after the function returns. */
4121 /* ??? tm.texi has no types for the parameters. */
4122 DEFHOOK
4123 (return_pops_args,
4124 "This target hook returns the number of bytes of its own arguments that\n\
4125 a function pops on returning, or 0 if the function pops no arguments\n\
4126 and the caller must therefore pop them all after the function returns.\n\
4128 @var{fundecl} is a C variable whose value is a tree node that describes\n\
4129 the function in question. Normally it is a node of type\n\
4130 @code{FUNCTION_DECL} that describes the declaration of the function.\n\
4131 From this you can obtain the @code{DECL_ATTRIBUTES} of the function.\n\
4133 @var{funtype} is a C variable whose value is a tree node that\n\
4134 describes the function in question. Normally it is a node of type\n\
4135 @code{FUNCTION_TYPE} that describes the data type of the function.\n\
4136 From this it is possible to obtain the data types of the value and\n\
4137 arguments (if known).\n\
4139 When a call to a library function is being considered, @var{fundecl}\n\
4140 will contain an identifier node for the library function. Thus, if\n\
4141 you need to distinguish among various library functions, you can do so\n\
4142 by their names. Note that ``library function'' in this context means\n\
4143 a function used to perform arithmetic, whose name is known specially\n\
4144 in the compiler and was not mentioned in the C code being compiled.\n\
4146 @var{size} is the number of bytes of arguments passed on the\n\
4147 stack. If a variable number of bytes is passed, it is zero, and\n\
4148 argument popping will always be the responsibility of the calling function.\n\
4150 On the VAX, all functions always pop their arguments, so the definition\n\
4151 of this macro is @var{size}. On the 68000, using the standard\n\
4152 calling convention, no functions pop their arguments, so the value of\n\
4153 the macro is always 0 in this case. But an alternative calling\n\
4154 convention is available in which functions that take a fixed number of\n\
4155 arguments pop them but other functions (such as @code{printf}) pop\n\
4156 nothing (the caller pops all). When this convention is in use,\n\
4157 @var{funtype} is examined to determine whether a function takes a fixed\n\
4158 number of arguments.",
4159 int, (tree fundecl, tree funtype, int size),
4160 default_return_pops_args)
4162 /* Return a mode wide enough to copy any function value that might be
4163 returned. */
4164 DEFHOOK
4165 (get_raw_result_mode,
4166 "This target hook returns the mode to be used when accessing raw return\
4167 registers in @code{__builtin_return}. Define this macro if the value\
4168 in @var{reg_raw_mode} is not correct.",
4169 enum machine_mode, (int regno),
4170 default_get_reg_raw_mode)
4172 /* Return a mode wide enough to copy any argument value that might be
4173 passed. */
4174 DEFHOOK
4175 (get_raw_arg_mode,
4176 "This target hook returns the mode to be used when accessing raw argument\
4177 registers in @code{__builtin_apply_args}. Define this macro if the value\
4178 in @var{reg_raw_mode} is not correct.",
4179 enum machine_mode, (int regno),
4180 default_get_reg_raw_mode)
4182 HOOK_VECTOR_END (calls)
4184 /* Return the diagnostic message string if conversion from FROMTYPE
4185 to TOTYPE is not allowed, NULL otherwise. */
4186 DEFHOOK
4187 (invalid_conversion,
4188 "If defined, this macro returns the diagnostic message when it is\n\
4189 invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}\n\
4190 if validity should be determined by the front end.",
4191 const char *, (const_tree fromtype, const_tree totype),
4192 hook_constcharptr_const_tree_const_tree_null)
4194 /* Return the diagnostic message string if the unary operation OP is
4195 not permitted on TYPE, NULL otherwise. */
4196 DEFHOOK
4197 (invalid_unary_op,
4198 "If defined, this macro returns the diagnostic message when it is\n\
4199 invalid to apply operation @var{op} (where unary plus is denoted by\n\
4200 @code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}\n\
4201 if validity should be determined by the front end.",
4202 const char *, (int op, const_tree type),
4203 hook_constcharptr_int_const_tree_null)
4205 /* Return the diagnostic message string if the binary operation OP
4206 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
4207 DEFHOOK
4208 (invalid_binary_op,
4209 "If defined, this macro returns the diagnostic message when it is\n\
4210 invalid to apply operation @var{op} to operands of types @var{type1}\n\
4211 and @var{type2}, or @code{NULL} if validity should be determined by\n\
4212 the front end.",
4213 const char *, (int op, const_tree type1, const_tree type2),
4214 hook_constcharptr_int_const_tree_const_tree_null)
4216 /* Return the diagnostic message string if TYPE is not valid as a
4217 function parameter type, NULL otherwise. */
4218 DEFHOOK
4219 (invalid_parameter_type,
4220 "If defined, this macro returns the diagnostic message when it is\n\
4221 invalid for functions to include parameters of type @var{type},\n\
4222 or @code{NULL} if validity should be determined by\n\
4223 the front end. This is currently used only by the C and C++ front ends.",
4224 const char *, (const_tree type),
4225 hook_constcharptr_const_tree_null)
4227 /* Return the diagnostic message string if TYPE is not valid as a
4228 function return type, NULL otherwise. */
4229 DEFHOOK
4230 (invalid_return_type,
4231 "If defined, this macro returns the diagnostic message when it is\n\
4232 invalid for functions to have return type @var{type},\n\
4233 or @code{NULL} if validity should be determined by\n\
4234 the front end. This is currently used only by the C and C++ front ends.",
4235 const char *, (const_tree type),
4236 hook_constcharptr_const_tree_null)
4238 /* If values of TYPE are promoted to some other type when used in
4239 expressions (analogous to the integer promotions), return that type,
4240 or NULL_TREE otherwise. */
4241 DEFHOOK
4242 (promoted_type,
4243 "If defined, this target hook returns the type to which values of\n\
4244 @var{type} should be promoted when they appear in expressions,\n\
4245 analogous to the integer promotions, or @code{NULL_TREE} to use the\n\
4246 front end's normal promotion rules. This hook is useful when there are\n\
4247 target-specific types with special promotion rules.\n\
4248 This is currently used only by the C and C++ front ends.",
4249 tree, (const_tree type),
4250 hook_tree_const_tree_null)
4252 /* Convert EXPR to TYPE, if target-specific types with special conversion
4253 rules are involved. Return the converted expression, or NULL to apply
4254 the standard conversion rules. */
4255 DEFHOOK
4256 (convert_to_type,
4257 "If defined, this hook returns the result of converting @var{expr} to\n\
4258 @var{type}. It should return the converted expression,\n\
4259 or @code{NULL_TREE} to apply the front end's normal conversion rules.\n\
4260 This hook is useful when there are target-specific types with special\n\
4261 conversion rules.\n\
4262 This is currently used only by the C and C++ front ends.",
4263 tree, (tree type, tree expr),
4264 hook_tree_tree_tree_null)
4266 /* Return true if we use LRA instead of reload. */
4267 DEFHOOK
4268 (lra_p,
4269 "A target hook which returns true if we use LRA instead of reload pass.\
4270 It means that LRA was ported to the target.\
4272 The default version of this target hook returns always false.",
4273 bool, (void),
4274 default_lra_p)
4276 /* Return register priority of given hard regno for the current target. */
4277 DEFHOOK
4278 (register_priority,
4279 "A target hook which returns the register priority number to which the\
4280 register @var{hard_regno} belongs to. The bigger the number, the\
4281 more preferable the hard register usage (when all other conditions are\
4282 the same). This hook can be used to prefer some hard register over\
4283 others in LRA. For example, some x86-64 register usage needs\
4284 additional prefix which makes instructions longer. The hook can\
4285 return lower priority number for such registers make them less favorable\
4286 and as result making the generated code smaller.\
4288 The default version of this target hook returns always zero.",
4289 int, (int),
4290 default_register_priority)
4292 /* Return true if we need register usage leveling. */
4293 DEFHOOK
4294 (register_usage_leveling_p,
4295 "A target hook which returns true if we need register usage leveling.\
4296 That means if a few hard registers are equally good for the\
4297 assignment, we choose the least used hard register. The register\
4298 usage leveling may be profitable for some targets. Don't use the\
4299 usage leveling for targets with conditional execution or targets\
4300 with big register files as it hurts if-conversion and cross-jumping\
4301 optimizations.\
4303 The default version of this target hook returns always false.",
4304 bool, (void),
4305 default_register_usage_leveling_p)
4307 /* Return true if maximal address displacement can be different. */
4308 DEFHOOK
4309 (different_addr_displacement_p,
4310 "A target hook which returns true if an address with the same structure\
4311 can have different maximal legitimate displacement. For example, the\
4312 displacement can depend on memory mode or on operand combinations in\
4313 the insn.\
4315 The default version of this target hook returns always false.",
4316 bool, (void),
4317 default_different_addr_displacement_p)
4319 /* Determine class for spilling pseudos of given mode into registers
4320 instead of memory. */
4321 DEFHOOK
4322 (spill_class,
4323 "This hook defines a class of registers which could be used for spilling\
4324 pseudos of the given mode and class, or @code{NO_REGS} if only memory\
4325 should be used. Not defining this hook is equivalent to returning\
4326 @code{NO_REGS} for all inputs.",
4327 reg_class_t, (reg_class_t, enum machine_mode),
4328 NULL)
4330 DEFHOOK
4331 (cstore_mode,
4332 "This hook defines the machine mode to use for the boolean result of\
4333 conditional store patterns. The ICODE argument is the instruction code\
4334 for the cstore being performed. Not definiting this hook is the same\
4335 as accepting the mode encoded into operand 0 of the cstore expander\
4336 patterns.",
4337 enum machine_mode, (enum insn_code icode),
4338 default_cstore_mode)
4340 /* True if a structure, union or array with MODE containing FIELD should
4341 be accessed using BLKmode. */
4342 DEFHOOK
4343 (member_type_forces_blk,
4344 "Return true if a structure, union or array containing @var{field} should\n\
4345 be accessed using @code{BLKMODE}.\n\
4347 If @var{field} is the only field in the structure, @var{mode} is its\n\
4348 mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the\n\
4349 case where structures of one field would require the structure's mode to\n\
4350 retain the field's mode.\n\
4352 Normally, this is not needed.",
4353 bool, (const_tree field, enum machine_mode mode),
4354 default_member_type_forces_blk)
4356 /* Return the class for a secondary reload, and fill in extra information. */
4357 DEFHOOK
4358 (secondary_reload,
4359 "Many machines have some registers that cannot be copied directly to or\n\
4360 from memory or even from other types of registers. An example is the\n\
4361 @samp{MQ} register, which on most machines, can only be copied to or\n\
4362 from general registers, but not memory. Below, we shall be using the\n\
4363 term 'intermediate register' when a move operation cannot be performed\n\
4364 directly, but has to be done by copying the source into the intermediate\n\
4365 register first, and then copying the intermediate register to the\n\
4366 destination. An intermediate register always has the same mode as\n\
4367 source and destination. Since it holds the actual value being copied,\n\
4368 reload might apply optimizations to re-use an intermediate register\n\
4369 and eliding the copy from the source when it can determine that the\n\
4370 intermediate register still holds the required value.\n\
4372 Another kind of secondary reload is required on some machines which\n\
4373 allow copying all registers to and from memory, but require a scratch\n\
4374 register for stores to some memory locations (e.g., those with symbolic\n\
4375 address on the RT, and those with certain symbolic address on the SPARC\n\
4376 when compiling PIC)@. Scratch registers need not have the same mode\n\
4377 as the value being copied, and usually hold a different value than\n\
4378 that being copied. Special patterns in the md file are needed to\n\
4379 describe how the copy is performed with the help of the scratch register;\n\
4380 these patterns also describe the number, register class(es) and mode(s)\n\
4381 of the scratch register(s).\n\
4383 In some cases, both an intermediate and a scratch register are required.\n\
4385 For input reloads, this target hook is called with nonzero @var{in_p},\n\
4386 and @var{x} is an rtx that needs to be copied to a register of class\n\
4387 @var{reload_class} in @var{reload_mode}. For output reloads, this target\n\
4388 hook is called with zero @var{in_p}, and a register of class @var{reload_class}\n\
4389 needs to be copied to rtx @var{x} in @var{reload_mode}.\n\
4391 If copying a register of @var{reload_class} from/to @var{x} requires\n\
4392 an intermediate register, the hook @code{secondary_reload} should\n\
4393 return the register class required for this intermediate register.\n\
4394 If no intermediate register is required, it should return NO_REGS.\n\
4395 If more than one intermediate register is required, describe the one\n\
4396 that is closest in the copy chain to the reload register.\n\
4398 If scratch registers are needed, you also have to describe how to\n\
4399 perform the copy from/to the reload register to/from this\n\
4400 closest intermediate register. Or if no intermediate register is\n\
4401 required, but still a scratch register is needed, describe the\n\
4402 copy from/to the reload register to/from the reload operand @var{x}.\n\
4404 You do this by setting @code{sri->icode} to the instruction code of a pattern\n\
4405 in the md file which performs the move. Operands 0 and 1 are the output\n\
4406 and input of this copy, respectively. Operands from operand 2 onward are\n\
4407 for scratch operands. These scratch operands must have a mode, and a\n\
4408 single-register-class\n\
4409 @c [later: or memory]\n\
4410 output constraint.\n\
4412 When an intermediate register is used, the @code{secondary_reload}\n\
4413 hook will be called again to determine how to copy the intermediate\n\
4414 register to/from the reload operand @var{x}, so your hook must also\n\
4415 have code to handle the register class of the intermediate operand.\n\
4417 @c [For later: maybe we'll allow multi-alternative reload patterns -\n\
4418 @c the port maintainer could name a mov<mode> pattern that has clobbers -\n\
4419 @c and match the constraints of input and output to determine the required\n\
4420 @c alternative. A restriction would be that constraints used to match\n\
4421 @c against reloads registers would have to be written as register class\n\
4422 @c constraints, or we need a new target macro / hook that tells us if an\n\
4423 @c arbitrary constraint can match an unknown register of a given class.\n\
4424 @c Such a macro / hook would also be useful in other places.]\n\
4427 @var{x} might be a pseudo-register or a @code{subreg} of a\n\
4428 pseudo-register, which could either be in a hard register or in memory.\n\
4429 Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is\n\
4430 in memory and the hard register number if it is in a register.\n\
4432 Scratch operands in memory (constraint @code{\"=m\"} / @code{\"=&m\"}) are\n\
4433 currently not supported. For the time being, you will have to continue\n\
4434 to use @code{SECONDARY_MEMORY_NEEDED} for that purpose.\n\
4436 @code{copy_cost} also uses this target hook to find out how values are\n\
4437 copied. If you want it to include some extra cost for the need to allocate\n\
4438 (a) scratch register(s), set @code{sri->extra_cost} to the additional cost.\n\
4439 Or if two dependent moves are supposed to have a lower cost than the sum\n\
4440 of the individual moves due to expected fortuitous scheduling and/or special\n\
4441 forwarding logic, you can set @code{sri->extra_cost} to a negative amount.",
4442 reg_class_t,
4443 (bool in_p, rtx x, reg_class_t reload_class, enum machine_mode reload_mode,
4444 secondary_reload_info *sri),
4445 default_secondary_reload)
4447 /* Given an rtx X being reloaded into a reg required to be in class CLASS,
4448 return the class of reg to actually use. */
4449 DEFHOOK
4450 (preferred_reload_class,
4451 "A target hook that places additional restrictions on the register class\n\
4452 to use when it is necessary to copy value @var{x} into a register in class\n\
4453 @var{rclass}. The value is a register class; perhaps @var{rclass}, or perhaps\n\
4454 another, smaller class.\n\
4456 The default version of this hook always returns value of @code{rclass} argument.\n\
4458 Sometimes returning a more restrictive class makes better code. For\n\
4459 example, on the 68000, when @var{x} is an integer constant that is in range\n\
4460 for a @samp{moveq} instruction, the value of this macro is always\n\
4461 @code{DATA_REGS} as long as @var{rclass} includes the data registers.\n\
4462 Requiring a data register guarantees that a @samp{moveq} will be used.\n\
4464 One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return\n\
4465 @var{rclass} is if @var{x} is a legitimate constant which cannot be\n\
4466 loaded into some register class. By returning @code{NO_REGS} you can\n\
4467 force @var{x} into a memory location. For example, rs6000 can load\n\
4468 immediate values into general-purpose registers, but does not have an\n\
4469 instruction for loading an immediate value into a floating-point\n\
4470 register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when\n\
4471 @var{x} is a floating-point constant. If the constant can't be loaded\n\
4472 into any kind of register, code generation will be better if\n\
4473 @code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead\n\
4474 of using @code{TARGET_PREFERRED_RELOAD_CLASS}.\n\
4476 If an insn has pseudos in it after register allocation, reload will go\n\
4477 through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}\n\
4478 to find the best one. Returning @code{NO_REGS}, in this case, makes\n\
4479 reload add a @code{!} in front of the constraint: the x86 back-end uses\n\
4480 this feature to discourage usage of 387 registers when math is done in\n\
4481 the SSE registers (and vice versa).",
4482 reg_class_t,
4483 (rtx x, reg_class_t rclass),
4484 default_preferred_reload_class)
4486 /* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
4487 input reloads. */
4488 DEFHOOK
4489 (preferred_output_reload_class,
4490 "Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of\n\
4491 input reloads.\n\
4493 The default version of this hook always returns value of @code{rclass}\n\
4494 argument.\n\
4496 You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage\n\
4497 reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.",
4498 reg_class_t,
4499 (rtx x, reg_class_t rclass),
4500 default_preferred_output_reload_class)
4502 DEFHOOK
4503 (class_likely_spilled_p,
4504 "A target hook which returns @code{true} if pseudos that have been assigned\n\
4505 to registers of class @var{rclass} would likely be spilled because\n\
4506 registers of @var{rclass} are needed for spill registers.\n\
4508 The default version of this target hook returns @code{true} if @var{rclass}\n\
4509 has exactly one register and @code{false} otherwise. On most machines, this\n\
4510 default should be used. For generally register-starved machines, such as\n\
4511 i386, or machines with right register constraints, such as SH, this hook\n\
4512 can be used to avoid excessive spilling.\n\
4514 This hook is also used by some of the global intra-procedural code\n\
4515 transformations to throtle code motion, to avoid increasing register\n\
4516 pressure.",
4517 bool, (reg_class_t rclass),
4518 default_class_likely_spilled_p)
4520 /* Return the maximum number of consecutive registers
4521 needed to represent mode MODE in a register of class RCLASS. */
4522 DEFHOOK
4523 (class_max_nregs,
4524 "A target hook returns the maximum number of consecutive registers\n\
4525 of class @var{rclass} needed to hold a value of mode @var{mode}.\n\
4527 This is closely related to the macro @code{HARD_REGNO_NREGS}. In fact,\n\
4528 the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},\n\
4529 @var{mode})} target hook should be the maximum value of\n\
4530 @code{HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}\n\
4531 values in the class @var{rclass}.\n\
4533 This target hook helps control the handling of multiple-word values\n\
4534 in the reload pass.\n\
4536 The default version of this target hook returns the size of @var{mode}\n\
4537 in words.",
4538 unsigned char, (reg_class_t rclass, enum machine_mode mode),
4539 default_class_max_nregs)
4541 DEFHOOK
4542 (preferred_rename_class,
4543 "A target hook that places additional preference on the register\
4544 class to use when it is necessary to rename a register in class\
4545 @var{rclass} to another class, or perhaps @var{NO_REGS}, if no\
4546 preferred register class is found or hook @code{preferred_rename_class}\
4547 is not implemented.\
4548 Sometimes returning a more restrictive class makes better code. For\
4549 example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\
4550 smaller than instructions using @code{GENERIC_REGS}. By returning\
4551 @code{LO_REGS} from @code{preferred_rename_class}, code size can\
4552 be reduced.",
4553 reg_class_t, (reg_class_t rclass),
4554 default_preferred_rename_class)
4556 /* This target hook allows the backend to perform additional
4557 processing while initializing for variable expansion. */
4558 DEFHOOK
4559 (expand_to_rtl_hook,
4560 "This hook is called just before expansion into rtl, allowing the target\n\
4561 to perform additional initializations or analysis before the expansion.\n\
4562 For example, the rs6000 port uses it to allocate a scratch stack slot\n\
4563 for use in copying SDmode values between memory and floating point\n\
4564 registers whenever the function being expanded has any SDmode\n\
4565 usage.",
4566 void, (void),
4567 hook_void_void)
4569 /* This target hook allows the backend to perform additional
4570 instantiations on rtx that are not actually in insns yet,
4571 but will be later. */
4572 DEFHOOK
4573 (instantiate_decls,
4574 "This hook allows the backend to perform additional instantiations on rtl\n\
4575 that are not actually in any insns yet, but will be later.",
4576 void, (void),
4577 hook_void_void)
4579 /* Return true if is OK to use a hard register REGNO as scratch register
4580 in peephole2. */
4581 DEFHOOK
4582 (hard_regno_scratch_ok,
4583 "This target hook should return @code{true} if it is OK to use a hard register\n\
4584 @var{regno} as scratch reg in peephole2.\n\
4586 One common use of this macro is to prevent using of a register that\n\
4587 is not saved by a prologue in an interrupt handler.\n\
4589 The default version of this hook always returns @code{true}.",
4590 bool, (unsigned int regno),
4591 default_hard_regno_scratch_ok)
4593 /* Return the smallest number of different values for which it is best to
4594 use a jump-table instead of a tree of conditional branches. */
4595 DEFHOOK
4596 (case_values_threshold,
4597 "This function return the smallest number of different values for which it\n\
4598 is best to use a jump-table instead of a tree of conditional branches.\n\
4599 The default is four for machines with a @code{casesi} instruction and\n\
4600 five otherwise. This is best for most machines.",
4601 unsigned int, (void),
4602 default_case_values_threshold)
4604 /* Retutn true if a function must have and use a frame pointer. */
4605 DEFHOOK
4606 (frame_pointer_required,
4607 "This target hook should return @code{true} if a function must have and use\n\
4608 a frame pointer. This target hook is called in the reload pass. If its return\n\
4609 value is @code{true} the function will have a frame pointer.\n\
4611 This target hook can in principle examine the current function and decide\n\
4612 according to the facts, but on most machines the constant @code{false} or the\n\
4613 constant @code{true} suffices. Use @code{false} when the machine allows code\n\
4614 to be generated with no frame pointer, and doing so saves some time or space.\n\
4615 Use @code{true} when there is no possible advantage to avoiding a frame\n\
4616 pointer.\n\
4618 In certain cases, the compiler does not know how to produce valid code\n\
4619 without a frame pointer. The compiler recognizes those cases and\n\
4620 automatically gives the function a frame pointer regardless of what\n\
4621 @code{TARGET_FRAME_POINTER_REQUIRED} returns. You don't need to worry about\n\
4622 them.\n\
4624 In a function that does not require a frame pointer, the frame pointer\n\
4625 register can be allocated for ordinary usage, unless you mark it as a\n\
4626 fixed register. See @code{FIXED_REGISTERS} for more information.\n\
4628 Default return value is @code{false}.",
4629 bool, (void),
4630 hook_bool_void_false)
4632 /* Returns true if the compiler is allowed to try to replace register number
4633 from-reg with register number to-reg. */
4634 DEFHOOK
4635 (can_eliminate,
4636 "This target hook should returns @code{true} if the compiler is allowed to\n\
4637 try to replace register number @var{from_reg} with register number\n\
4638 @var{to_reg}. This target hook need only be defined if @code{ELIMINABLE_REGS}\n\
4639 is defined, and will usually be @code{true}, since most of the cases\n\
4640 preventing register elimination are things that the compiler already\n\
4641 knows about.\n\
4643 Default return value is @code{true}.",
4644 bool, (const int from_reg, const int to_reg),
4645 hook_bool_const_int_const_int_true)
4647 /* Modify any or all of fixed_regs, call_used_regs, global_regs,
4648 reg_names, and reg_class_contents to account of the vagaries of the
4649 target. */
4650 DEFHOOK
4651 (conditional_register_usage,
4652 "This hook may conditionally modify five variables\n\
4653 @code{fixed_regs}, @code{call_used_regs}, @code{global_regs},\n\
4654 @code{reg_names}, and @code{reg_class_contents}, to take into account\n\
4655 any dependence of these register sets on target flags. The first three\n\
4656 of these are of type @code{char []} (interpreted as Boolean vectors).\n\
4657 @code{global_regs} is a @code{const char *[]}, and\n\
4658 @code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is\n\
4659 called, @code{fixed_regs}, @code{call_used_regs},\n\
4660 @code{reg_class_contents}, and @code{reg_names} have been initialized\n\
4661 from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},\n\
4662 @code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.\n\
4663 @code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},\n\
4664 @option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}\n\
4665 command options have been applied.\n\
4667 @cindex disabling certain registers\n\
4668 @cindex controlling register usage\n\
4669 If the usage of an entire class of registers depends on the target\n\
4670 flags, you may indicate this to GCC by using this macro to modify\n\
4671 @code{fixed_regs} and @code{call_used_regs} to 1 for each of the\n\
4672 registers in the classes which should not be used by GCC@. Also define\n\
4673 the macro @code{REG_CLASS_FROM_LETTER} / @code{REG_CLASS_FROM_CONSTRAINT}\n\
4674 to return @code{NO_REGS} if it\n\
4675 is called with a letter for a class that shouldn't be used.\n\
4677 (However, if this class is not included in @code{GENERAL_REGS} and all\n\
4678 of the insn patterns whose constraints permit this class are\n\
4679 controlled by target switches, then GCC will automatically avoid using\n\
4680 these registers when the target switches are opposed to them.)",
4681 void, (void),
4682 hook_void_void)
4684 /* Functions specific to the C family of frontends. */
4685 #undef HOOK_PREFIX
4686 #define HOOK_PREFIX "TARGET_C_"
4687 HOOK_VECTOR (TARGET_C, c)
4689 /* ??? Documenting this hook requires a GFDL license grant. */
4690 DEFHOOK_UNDOC
4691 (mode_for_suffix,
4692 "Return machine mode for non-standard constant literal suffix @var{c},\
4693 or VOIDmode if non-standard suffixes are unsupported.",
4694 enum machine_mode, (char c),
4695 default_mode_for_suffix)
4697 HOOK_VECTOR_END (c)
4699 /* Functions specific to the C++ frontend. */
4700 #undef HOOK_PREFIX
4701 #define HOOK_PREFIX "TARGET_CXX_"
4702 HOOK_VECTOR (TARGET_CXX, cxx)
4704 /* Return the integer type used for guard variables. */
4705 DEFHOOK
4706 (guard_type,
4707 "Define this hook to override the integer type used for guard variables.\n\
4708 These are used to implement one-time construction of static objects. The\n\
4709 default is long_long_integer_type_node.",
4710 tree, (void),
4711 default_cxx_guard_type)
4713 /* Return true if only the low bit of the guard should be tested. */
4714 DEFHOOK
4715 (guard_mask_bit,
4716 "This hook determines how guard variables are used. It should return\n\
4717 @code{false} (the default) if the first byte should be used. A return value of\n\
4718 @code{true} indicates that only the least significant bit should be used.",
4719 bool, (void),
4720 hook_bool_void_false)
4722 /* Returns the size of the array cookie for an array of type. */
4723 DEFHOOK
4724 (get_cookie_size,
4725 "This hook returns the size of the cookie to use when allocating an array\n\
4726 whose elements have the indicated @var{type}. Assumes that it is already\n\
4727 known that a cookie is needed. The default is\n\
4728 @code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the\n\
4729 IA64/Generic C++ ABI@.",
4730 tree, (tree type),
4731 default_cxx_get_cookie_size)
4733 /* Returns true if the element size should be stored in the array cookie. */
4734 DEFHOOK
4735 (cookie_has_size,
4736 "This hook should return @code{true} if the element size should be stored in\n\
4737 array cookies. The default is to return @code{false}.",
4738 bool, (void),
4739 hook_bool_void_false)
4741 /* Allows backends to perform additional processing when
4742 deciding if a class should be exported or imported. */
4743 DEFHOOK
4744 (import_export_class,
4745 "If defined by a backend this hook allows the decision made to export\n\
4746 class @var{type} to be overruled. Upon entry @var{import_export}\n\
4747 will contain 1 if the class is going to be exported, @minus{}1 if it is going\n\
4748 to be imported and 0 otherwise. This function should return the\n\
4749 modified value and perform any other actions necessary to support the\n\
4750 backend's targeted operating system.",
4751 int, (tree type, int import_export), NULL)
4753 /* Returns true if constructors and destructors return "this". */
4754 DEFHOOK
4755 (cdtor_returns_this,
4756 "This hook should return @code{true} if constructors and destructors return\n\
4757 the address of the object created/destroyed. The default is to return\n\
4758 @code{false}.",
4759 bool, (void),
4760 hook_bool_void_false)
4762 /* Returns true if the key method for a class can be an inline
4763 function, so long as it is not declared inline in the class
4764 itself. Returning true is the behavior required by the Itanium C++ ABI. */
4765 DEFHOOK
4766 (key_method_may_be_inline,
4767 "This hook returns true if the key method for a class (i.e., the method\n\
4768 which, if defined in the current translation unit, causes the virtual\n\
4769 table to be emitted) may be an inline function. Under the standard\n\
4770 Itanium C++ ABI the key method may be an inline function so long as\n\
4771 the function is not declared inline in the class definition. Under\n\
4772 some variants of the ABI, an inline function can never be the key\n\
4773 method. The default is to return @code{true}.",
4774 bool, (void),
4775 hook_bool_void_true)
4777 DEFHOOK
4778 (determine_class_data_visibility,
4779 "@var{decl} is a virtual table, virtual table table, typeinfo object,\
4780 or other similar implicit class data object that will be emitted with\
4781 external linkage in this translation unit. No ELF visibility has been\
4782 explicitly specified. If the target needs to specify a visibility\
4783 other than that of the containing class, use this hook to set\
4784 @code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
4785 void, (tree decl),
4786 hook_void_tree)
4788 /* Returns true (the default) if virtual tables and other
4789 similar implicit class data objects are always COMDAT if they
4790 have external linkage. If this hook returns false, then
4791 class data for classes whose virtual table will be emitted in
4792 only one translation unit will not be COMDAT. */
4793 DEFHOOK
4794 (class_data_always_comdat,
4795 "This hook returns true (the default) if virtual tables and other\n\
4796 similar implicit class data objects are always COMDAT if they have\n\
4797 external linkage. If this hook returns false, then class data for\n\
4798 classes whose virtual table will be emitted in only one translation\n\
4799 unit will not be COMDAT.",
4800 bool, (void),
4801 hook_bool_void_true)
4803 /* Returns true (the default) if the RTTI for the basic types,
4804 which is always defined in the C++ runtime, should be COMDAT;
4805 false if it should not be COMDAT. */
4806 DEFHOOK
4807 (library_rtti_comdat,
4808 "This hook returns true (the default) if the RTTI information for\n\
4809 the basic types which is defined in the C++ runtime should always\n\
4810 be COMDAT, false if it should not be COMDAT.",
4811 bool, (void),
4812 hook_bool_void_true)
4814 /* Returns true if __aeabi_atexit should be used to register static
4815 destructors. */
4816 DEFHOOK
4817 (use_aeabi_atexit,
4818 "This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)\n\
4819 should be used to register static destructors when @option{-fuse-cxa-atexit}\n\
4820 is in effect. The default is to return false to use @code{__cxa_atexit}.",
4821 bool, (void),
4822 hook_bool_void_false)
4824 /* Returns true if target may use atexit in the same manner as
4825 __cxa_atexit to register static destructors. */
4826 DEFHOOK
4827 (use_atexit_for_cxa_atexit,
4828 "This hook returns true if the target @code{atexit} function can be used\n\
4829 in the same manner as @code{__cxa_atexit} to register C++ static\n\
4830 destructors. This requires that @code{atexit}-registered functions in\n\
4831 shared libraries are run in the correct order when the libraries are\n\
4832 unloaded. The default is to return false.",
4833 bool, (void),
4834 hook_bool_void_false)
4836 DEFHOOK
4837 (adjust_class_at_definition,
4838 "@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\
4839 been defined. Use this hook to make adjustments to the class (eg, tweak\
4840 visibility or perform any other required target modifications).",
4841 void, (tree type),
4842 hook_void_tree)
4844 DEFHOOK
4845 (decl_mangling_context,
4846 "Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
4847 tree, (const_tree decl),
4848 hook_tree_const_tree_null)
4850 HOOK_VECTOR_END (cxx)
4852 /* Functions and data for emulated TLS support. */
4853 #undef HOOK_PREFIX
4854 #define HOOK_PREFIX "TARGET_EMUTLS_"
4855 HOOK_VECTOR (TARGET_EMUTLS, emutls)
4857 /* Name of the address and common functions. */
4858 DEFHOOKPOD
4859 (get_address,
4860 "Contains the name of the helper function that uses a TLS control\n\
4861 object to locate a TLS instance. The default causes libgcc's\n\
4862 emulated TLS helper function to be used.",
4863 const char *, "__builtin___emutls_get_address")
4865 DEFHOOKPOD
4866 (register_common,
4867 "Contains the name of the helper function that should be used at\n\
4868 program startup to register TLS objects that are implicitly\n\
4869 initialized to zero. If this is @code{NULL}, all TLS objects will\n\
4870 have explicit initializers. The default causes libgcc's emulated TLS\n\
4871 registration function to be used.",
4872 const char *, "__builtin___emutls_register_common")
4874 /* Prefixes for proxy variable and template. */
4875 DEFHOOKPOD
4876 (var_section,
4877 "Contains the name of the section in which TLS control variables should\n\
4878 be placed. The default of @code{NULL} allows these to be placed in\n\
4879 any section.",
4880 const char *, NULL)
4882 DEFHOOKPOD
4883 (tmpl_section,
4884 "Contains the name of the section in which TLS initializers should be\n\
4885 placed. The default of @code{NULL} allows these to be placed in any\n\
4886 section.",
4887 const char *, NULL)
4889 /* Prefixes for proxy variable and template. */
4890 DEFHOOKPOD
4891 (var_prefix,
4892 "Contains the prefix to be prepended to TLS control variable names.\n\
4893 The default of @code{NULL} uses a target-specific prefix.",
4894 const char *, NULL)
4896 DEFHOOKPOD
4897 (tmpl_prefix,
4898 "Contains the prefix to be prepended to TLS initializer objects. The\n\
4899 default of @code{NULL} uses a target-specific prefix.",
4900 const char *, NULL)
4902 /* Function to generate field definitions of the proxy variable. */
4903 DEFHOOK
4904 (var_fields,
4905 "Specifies a function that generates the FIELD_DECLs for a TLS control\n\
4906 object type. @var{type} is the RECORD_TYPE the fields are for and\n\
4907 @var{name} should be filled with the structure tag, if the default of\n\
4908 @code{__emutls_object} is unsuitable. The default creates a type suitable\n\
4909 for libgcc's emulated TLS function.",
4910 tree, (tree type, tree *name),
4911 default_emutls_var_fields)
4913 /* Function to initialize a proxy variable. */
4914 DEFHOOK
4915 (var_init,
4916 "Specifies a function that generates the CONSTRUCTOR to initialize a\n\
4917 TLS control object. @var{var} is the TLS control object, @var{decl}\n\
4918 is the TLS object and @var{tmpl_addr} is the address of the\n\
4919 initializer. The default initializes libgcc's emulated TLS control object.",
4920 tree, (tree var, tree decl, tree tmpl_addr),
4921 default_emutls_var_init)
4923 /* Whether we are allowed to alter the usual alignment of the
4924 proxy variable. */
4925 DEFHOOKPOD
4926 (var_align_fixed,
4927 "Specifies whether the alignment of TLS control variable objects is\n\
4928 fixed and should not be increased as some backends may do to optimize\n\
4929 single objects. The default is false.",
4930 bool, false)
4932 /* Whether we can emit debug information for TLS vars. */
4933 DEFHOOKPOD
4934 (debug_form_tls_address,
4935 "Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor\n\
4936 may be used to describe emulated TLS control objects.",
4937 bool, false)
4939 HOOK_VECTOR_END (emutls)
4941 #undef HOOK_PREFIX
4942 #define HOOK_PREFIX "TARGET_OPTION_"
4943 HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)
4945 /* Function to validate the attribute((target(...))) strings. If
4946 the option is validated, the hook should also fill in
4947 DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
4948 DEFHOOK
4949 (valid_attribute_p,
4950 "This hook is called to parse @code{attribute(target(\"...\"))}, which\n\
4951 allows setting target-specific options on individual functions.\n\
4952 These function-specific options may differ\n\
4953 from the options specified on the command line. The hook should return\n\
4954 @code{true} if the options are valid.\n\
4956 The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
4957 the function declaration to hold a pointer to a target-specific\n\
4958 @code{struct cl_target_option} structure.",
4959 bool, (tree fndecl, tree name, tree args, int flags),
4960 default_target_option_valid_attribute_p)
4962 /* Function to save any extra target state in the target options structure. */
4963 DEFHOOK
4964 (save,
4965 "This hook is called to save any additional target-specific information\n\
4966 in the @code{struct cl_target_option} structure for function-specific\n\
4967 options.\n\
4968 @xref{Option file format}.",
4969 void, (struct cl_target_option *ptr), NULL)
4971 /* Function to restore any extra target state from the target options
4972 structure. */
4973 DEFHOOK
4974 (restore,
4975 "This hook is called to restore any additional target-specific\n\
4976 information in the @code{struct cl_target_option} structure for\n\
4977 function-specific options.",
4978 void, (struct cl_target_option *ptr), NULL)
4980 /* Function to print any extra target state from the target options
4981 structure. */
4982 DEFHOOK
4983 (print,
4984 "This hook is called to print any additional target-specific\n\
4985 information in the @code{struct cl_target_option} structure for\n\
4986 function-specific options.",
4987 void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)
4989 /* Function to parse arguments to be validated for #pragma target, and to
4990 change the state if the options are valid. If the first argument is
4991 NULL, the second argument specifies the default options to use. Return
4992 true if the options are valid, and set the current state. */
4993 DEFHOOK
4994 (pragma_parse,
4995 "This target hook parses the options for @code{#pragma GCC target}, which\n\
4996 sets the target-specific options for functions that occur later in the\n\
4997 input stream. The options accepted should be the same as those handled by the\n\
4998 @code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.",
4999 bool, (tree args, tree pop_target),
5000 default_target_option_pragma_parse)
5002 /* Do option overrides for the target. */
5003 DEFHOOK
5004 (override,
5005 "Sometimes certain combinations of command options do not make sense on\n\
5006 a particular target machine. You can override the hook\n\
5007 @code{TARGET_OPTION_OVERRIDE} to take account of this. This hooks is called\n\
5008 once just after all the command options have been parsed.\n\
5010 Don't use this hook to turn on various extra optimizations for\n\
5011 @option{-O}. That is what @code{TARGET_OPTION_OPTIMIZATION} is for.\n\
5013 If you need to do something whenever the optimization level is\n\
5014 changed via the optimize attribute or pragma, see\n\
5015 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}",
5016 void, (void),
5017 hook_void_void)
5019 /* This function returns true if DECL1 and DECL2 are versions of the same
5020 function. DECL1 and DECL2 are function versions if and only if they
5021 have the same function signature and different target specific attributes,
5022 that is, they are compiled for different target machines. */
5023 DEFHOOK
5024 (function_versions,
5025 "This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are\n\
5026 versions of the same function. @var{DECL1} and @var{DECL2} are function\n\
5027 versions if and only if they have the same function signature and\n\
5028 different target specific attributes, that is, they are compiled for\n\
5029 different target machines.",
5030 bool, (tree decl1, tree decl2),
5031 hook_bool_tree_tree_false)
5033 /* Function to determine if one function can inline another function. */
5034 #undef HOOK_PREFIX
5035 #define HOOK_PREFIX "TARGET_"
5036 DEFHOOK
5037 (can_inline_p,
5038 "This target hook returns @code{false} if the @var{caller} function\n\
5039 cannot inline @var{callee}, based on target specific information. By\n\
5040 default, inlining is not allowed if the callee function has function\n\
5041 specific target options and the caller does not use the same options.",
5042 bool, (tree caller, tree callee),
5043 default_target_can_inline_p)
5045 HOOK_VECTOR_END (target_option)
5047 /* For targets that need to mark extra registers as live on entry to
5048 the function, they should define this target hook and set their
5049 bits in the bitmap passed in. */
5050 DEFHOOK
5051 (extra_live_on_entry,
5052 "Add any hard registers to @var{regs} that are live on entry to the\n\
5053 function. This hook only needs to be defined to provide registers that\n\
5054 cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved\n\
5055 registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,\n\
5056 TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,\n\
5057 FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.",
5058 void, (bitmap regs),
5059 hook_void_bitmap)
5061 /* Fill in additional registers set up by prologue into a regset. */
5062 DEFHOOK
5063 (set_up_by_prologue,
5064 "This hook should add additional registers that are computed by the prologue\
5065 to the hard regset for shrink-wrapping optimization purposes.",
5066 void, (struct hard_reg_set_container *),
5067 NULL)
5069 /* For targets that have attributes that can affect whether a
5070 function's return statements need checking. For instance a 'naked'
5071 function attribute. */
5072 DEFHOOK
5073 (warn_func_return,
5074 "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.",
5075 bool, (tree),
5076 hook_bool_tree_true)
5078 /* Determine the type of unwind info to emit for debugging. */
5079 DEFHOOK
5080 (debug_unwind_info,
5081 "This hook defines the mechanism that will be used for describing frame\n\
5082 unwind information to the debugger. Normally the hook will return\n\
5083 @code{UI_DWARF2} if DWARF 2 debug information is enabled, and\n\
5084 return @code{UI_NONE} otherwise.\n\
5086 A target may return @code{UI_DWARF2} even when DWARF 2 debug information\n\
5087 is disabled in order to always output DWARF 2 frame information.\n\
5089 A target may return @code{UI_TARGET} if it has ABI specified unwind tables.\n\
5090 This will suppress generation of the normal debug frame unwind information.",
5091 enum unwind_info_type, (void),
5092 default_debug_unwind_info)
5094 /* The code parameter should be of type enum rtx_code but this is not
5095 defined at this time. */
5096 DEFHOOK
5097 (canonicalize_comparison,
5098 "On some machines not all possible comparisons are defined, but you can\n\
5099 convert an invalid comparison into a valid one. For example, the Alpha\n\
5100 does not have a @code{GT} comparison, but you can use an @code{LT}\n\
5101 comparison instead and swap the order of the operands.\n\
5103 On such machines, implement this hook to do any required conversions.\n\
5104 @var{code} is the initial comparison code and @var{op0} and @var{op1}\n\
5105 are the left and right operands of the comparison, respectively. If\n\
5106 @var{op0_preserve_value} is @code{true} the implementation is not\n\
5107 allowed to change the value of @var{op0} since the value might be used\n\
5108 in RTXs which aren't comparisons. E.g. the implementation is not\n\
5109 allowed to swap operands in that case.\n\
5111 GCC will not assume that the comparison resulting from this macro is\n\
5112 valid but will see if the resulting insn matches a pattern in the\n\
5113 @file{md} file.\n\
5115 You need not to implement this hook if it would never change the\n\
5116 comparison code or operands.",
5117 void, (int *code, rtx *op0, rtx *op1, bool op0_preserve_value),
5118 default_canonicalize_comparison)
5120 DEFHOOKPOD
5121 (atomic_test_and_set_trueval,
5122 "This value should be set if the result written by\
5123 @code{atomic_test_and_set} is not exactly 1, i.e. the\
5124 @code{bool} @code{true}.",
5125 unsigned char, 1)
5127 /* Leave the boolean fields at the end. */
5129 /* True if we can create zeroed data by switching to a BSS section
5130 and then using ASM_OUTPUT_SKIP to allocate the space. */
5131 DEFHOOKPOD
5132 (have_switchable_bss_sections,
5133 "This flag is true if we can create zeroed data by switching to a BSS\n\
5134 section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.\n\
5135 This is true on most ELF targets.",
5136 bool, false)
5138 /* True if "native" constructors and destructors are supported,
5139 false if we're using collect2 for the job. */
5140 DEFHOOKPOD
5141 (have_ctors_dtors,
5142 "This value is true if the target supports some ``native'' method of\n\
5143 collecting constructors and destructors to be run at startup and exit.\n\
5144 It is false if we must use @command{collect2}.",
5145 bool, false)
5147 /* True if thread-local storage is supported. */
5148 DEFHOOKPOD
5149 (have_tls,
5150 "Contains the value true if the target supports thread-local storage.\n\
5151 The default value is false.",
5152 bool, false)
5154 /* True if a small readonly data section is supported. */
5155 DEFHOOKPOD
5156 (have_srodata_section,
5157 "Contains the value true if the target places read-only\n\
5158 ``small data'' into a separate section. The default value is false.",
5159 bool, false)
5161 /* True if EH frame info sections should be zero-terminated. */
5162 DEFHOOKPOD
5163 (terminate_dw2_eh_frame_info,
5164 "Contains the value true if the target should add a zero word onto the\n\
5165 end of a Dwarf-2 frame info section when used for exception handling.\n\
5166 Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and\n\
5167 true otherwise.",
5168 bool, true)
5170 /* True if #NO_APP should be emitted at the beginning of assembly output. */
5171 DEFHOOKPOD
5172 (asm_file_start_app_off,
5173 "If this flag is true, the text of the macro @code{ASM_APP_OFF} will be\n\
5174 printed as the very first line in the assembly file, unless\n\
5175 @option{-fverbose-asm} is in effect. (If that macro has been defined\n\
5176 to the empty string, this variable has no effect.) With the normal\n\
5177 definition of @code{ASM_APP_OFF}, the effect is to notify the GNU\n\
5178 assembler that it need not bother stripping comments or extra\n\
5179 whitespace from its input. This allows it to work a bit faster.\n\
5181 The default is false. You should not set it to true unless you have\n\
5182 verified that your port does not generate any extra whitespace or\n\
5183 comments that will cause GAS to issue errors in NO_APP mode.",
5184 bool, false)
5186 /* True if output_file_directive should be called for main_input_filename
5187 at the beginning of assembly output. */
5188 DEFHOOKPOD
5189 (asm_file_start_file_directive,
5190 "If this flag is true, @code{output_file_directive} will be called\n\
5191 for the primary source file, immediately after printing\n\
5192 @code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect\n\
5193 this to be done. The default is false.",
5194 bool, false)
5196 /* True if the target is allowed to reorder memory accesses unless
5197 synchronization is explicitly requested. */
5198 DEFHOOKPOD
5199 (relaxed_ordering,
5200 "If set to @code{true}, means that the target's memory model does not\n\
5201 guarantee that loads which do not depend on one another will access\n\
5202 main memory in the order of the instruction stream; if ordering is\n\
5203 important, an explicit memory barrier must be used. This is true of\n\
5204 many recent processors which implement a policy of ``relaxed,''\n\
5205 ``weak,'' or ``release'' memory consistency, such as Alpha, PowerPC,\n\
5206 and ia64. The default is @code{false}.",
5207 bool, false)
5209 /* Returns true if we should generate exception tables for use with the
5210 ARM EABI. The effects the encoding of function exception specifications. */
5211 DEFHOOKPOD
5212 (arm_eabi_unwinder,
5213 "This flag should be set to @code{true} on targets that use an ARM EABI\n\
5214 based unwinding library, and @code{false} on other targets. This effects\n\
5215 the format of unwinding tables, and how the unwinder in entered after\n\
5216 running a cleanup. The default is @code{false}.",
5217 bool, false)
5219 DEFHOOKPOD
5220 (want_debug_pub_sections,
5221 "True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\
5222 should be emitted. These sections are not used on most platforms, and\
5223 in particular GDB does not use them.",
5224 bool, false)
5226 DEFHOOKPOD
5227 (force_at_comp_dir,
5228 "True if the @code{DW_AT_comp_dir} attribute should be emitted for each \
5229 compilation unit. This attribute is required for the darwin linker \
5230 to emit debug information.",
5231 bool, false)
5233 DEFHOOKPOD
5234 (delay_sched2, "True if sched2 is not to be run at its normal place. \
5235 This usually means it will be run as part of machine-specific reorg.",
5236 bool, false)
5238 DEFHOOKPOD
5239 (delay_vartrack, "True if vartrack is not to be run at its normal place. \
5240 This usually means it will be run as part of machine-specific reorg.",
5241 bool, false)
5243 /* Leave the boolean fields at the end. */
5245 /* Close the 'struct gcc_target' definition. */
5246 HOOK_VECTOR_END (C90_EMPTY_HACK)