1 /* Target hook definitions.
2 Copyright (C) 2001-2015 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
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"
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. */
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.",
42 DEFHOOKPODX (close_paren, const char *, ")")
44 /* Assembler instructions for creating various kinds of integer object. */
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\
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. */
71 (label_align_after_barrier_max_skip,
72 "The maximum number of bytes to skip before @var{label} when applying\n\
73 @code{LABEL_ALIGN_AFTER_BARRIER}. This works only if\n\
74 @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.",
75 int, (rtx_insn *label),
76 default_label_align_after_barrier_max_skip)
78 /* The maximum number of bytes to skip when applying
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\
85 int, (rtx_insn *label),
86 default_loop_align_max_skip)
88 /* The maximum number of bytes to skip when applying
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\
95 int, (rtx_insn *label),
96 default_label_align_max_skip)
98 /* The maximum number of bytes to skip when applying
101 (jump_align_max_skip,
102 "The maximum number of bytes to skip before @var{label} when applying\n\
103 @code{JUMP_ALIGN}. This works only if\n\
104 @code{ASM_OUTPUT_MAX_SKIP_ALIGN} is defined.",
105 int, (rtx_insn *label),
106 default_jump_align_max_skip)
108 /* Try to output the assembler code for an integer object whose
109 value is given by X. SIZE is the size of the object in bytes and
110 ALIGNED_P indicates whether it is aligned. Return true if
111 successful. Only handles cases for which BYTE_OP, ALIGNED_OP
112 and UNALIGNED_OP are NULL. */
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
127 bool, (rtx x, unsigned int size, int aligned_p),
128 default_assemble_integer)
130 /* Notify the backend that we have completed emitting the data for a
134 "Define this hook if the target assembler requires a special marker to\n\
135 terminate an initialized variable declaration.",
139 /* Output code that will globalize a label. */
142 "This target hook is a function to output to the stdio stream\n\
143 @var{stream} some commands that will make the label @var{name} global;\n\
144 that is, available for reference from other files.\n\
146 The default implementation relies on a proper definition of\n\
147 @code{GLOBAL_ASM_OP}.",
148 void, (FILE *stream, const char *name),
149 default_globalize_label)
151 /* Output code that will globalize a declaration. */
153 (globalize_decl_name,
154 "This target hook is a function to output to the stdio stream\n\
155 @var{stream} some commands that will make the name associated with @var{decl}\n\
156 global; that is, available for reference from other files.\n\
158 The default implementation uses the TARGET_ASM_GLOBALIZE_LABEL target hook.",
159 void, (FILE *stream, tree decl), default_globalize_decl_name)
161 /* Output code that will declare an external variable. */
163 (assemble_undefined_decl,
164 "This target hook is a function to output to the stdio stream\n\
165 @var{stream} some commands that will declare the name associated with\n\
166 @var{decl} which is not defined in the current translation unit. Most\n\
167 assemblers do not require anything to be output in this case.",
168 void, (FILE *stream, const char *name, const_tree decl),
169 hook_void_FILEptr_constcharptr_const_tree)
171 /* Output code that will emit a label for unwind info, if this
172 target requires such labels. Second argument is the decl the
173 unwind info is associated with, third is a boolean: true if
174 this is for exception handling, fourth is a boolean: true if
175 this is only a placeholder for an omitted FDE. */
178 "This target hook emits a label at the beginning of each FDE@. It\n\
179 should be defined on targets where FDEs need special labels, and it\n\
180 should write the appropriate label, for the FDE associated with the\n\
181 function declaration @var{decl}, to the stdio stream @var{stream}.\n\
182 The third argument, @var{for_eh}, is a boolean: true if this is for an\n\
183 exception table. The fourth argument, @var{empty}, is a boolean:\n\
184 true if this is a placeholder label for an omitted FDE@.\n\
186 The default is that FDEs are not given nonlocal labels.",
187 void, (FILE *stream, tree decl, int for_eh, int empty),
188 default_emit_unwind_label)
190 /* Output code that will emit a label to divide up the exception table. */
192 (emit_except_table_label,
193 "This target hook emits a label at the beginning of the exception table.\n\
194 It should be defined on targets where it is desirable for the table\n\
195 to be broken up according to function.\n\
197 The default is that no label is emitted.",
198 void, (FILE *stream),
199 default_emit_except_table_label)
201 /* Emit a directive for setting the personality for the function. */
203 (emit_except_personality,
204 "If the target implements @code{TARGET_ASM_UNWIND_EMIT}, this hook may be\
205 used to emit a directive to install a personality hook into the unwind\
206 info. This hook should not be used if dwarf2 unwind info is used.",
207 void, (rtx personality),
210 /* Emit any directives required to unwind this instruction. */
213 "This target hook emits assembly directives required to unwind the\n\
214 given instruction. This is only used when @code{TARGET_EXCEPT_UNWIND_INFO}\n\
215 returns @code{UI_TARGET}.",
216 void, (FILE *stream, rtx_insn *insn),
220 (unwind_emit_before_insn,
221 "True if the @code{TARGET_ASM_UNWIND_EMIT} hook should be called before\
222 the assembly for @var{insn} has been emitted, false if the hook should\
223 be called afterward.",
226 /* Generate an internal label.
227 For now this is just a wrapper for ASM_GENERATE_INTERNAL_LABEL. */
229 (generate_internal_label,
231 void, (char *buf, const char *prefix, unsigned long labelno),
232 default_generate_internal_label)
234 /* Output an internal label. */
237 "A function to output to the stdio stream @var{stream} a label whose\n\
238 name is made from the string @var{prefix} and the number @var{labelno}.\n\
240 It is absolutely essential that these labels be distinct from the labels\n\
241 used for user-level functions and variables. Otherwise, certain programs\n\
242 will have name conflicts with internal labels.\n\
244 It is desirable to exclude internal labels from the symbol table of the\n\
245 object file. Most assemblers have a naming convention for labels that\n\
246 should be excluded; on many systems, the letter @samp{L} at the\n\
247 beginning of a label has this effect. You should find out what\n\
248 convention your system uses, and follow it.\n\
250 The default version of this function utilizes @code{ASM_GENERATE_INTERNAL_LABEL}.",
251 void, (FILE *stream, const char *prefix, unsigned long labelno),
252 default_internal_label)
254 /* Output label for the constant. */
256 (declare_constant_name,
257 "A target hook to output to the stdio stream @var{file} any text necessary\n\
258 for declaring the name @var{name} of a constant which is being defined. This\n\
259 target hook is responsible for outputting the label definition (perhaps using\n\
260 @code{assemble_label}). The argument @var{exp} is the value of the constant,\n\
261 and @var{size} is the size of the constant in bytes. The @var{name}\n\
262 will be an internal label.\n\
264 The default version of this target hook, define the @var{name} in the\n\
265 usual manner as a label (by means of @code{assemble_label}).\n\
267 You may wish to use @code{ASM_OUTPUT_TYPE_DIRECTIVE} in this target hook.",
268 void, (FILE *file, const char *name, const_tree expr, HOST_WIDE_INT size),
269 default_asm_declare_constant_name)
271 /* Emit a ttype table reference to a typeinfo object. */
274 "This hook is used to output a reference from a frame unwinding table to\n\
275 the type_info object identified by @var{sym}. It should return @code{true}\n\
276 if the reference was output. Returning @code{false} will cause the\n\
277 reference to be output using the normal Dwarf2 routines.",
281 /* Emit an assembler directive to set visibility for the symbol
282 associated with the tree decl. */
284 (assemble_visibility,
285 "This target hook is a function to output to @var{asm_out_file} some\n\
286 commands that will make the symbol(s) associated with @var{decl} have\n\
287 hidden, protected or internal visibility as specified by @var{visibility}.",
288 void, (tree decl, int visibility),
289 default_assemble_visibility)
291 /* Output the assembler code for entry to a function. */
294 "If defined, a function that outputs the assembler code for entry to a\n\
295 function. The prologue is responsible for setting up the stack frame,\n\
296 initializing the frame pointer register, saving registers that must be\n\
297 saved, and allocating @var{size} additional bytes of storage for the\n\
298 local variables. @var{size} is an integer. @var{file} is a stdio\n\
299 stream to which the assembler code should be output.\n\
301 The label for the beginning of the function need not be output by this\n\
302 macro. That has already been done when the macro is run.\n\
304 @findex regs_ever_live\n\
305 To determine which registers to save, the macro can refer to the array\n\
306 @code{regs_ever_live}: element @var{r} is nonzero if hard register\n\
307 @var{r} is used anywhere within the function. This implies the function\n\
308 prologue should save register @var{r}, provided it is not one of the\n\
309 call-used registers. (@code{TARGET_ASM_FUNCTION_EPILOGUE} must likewise use\n\
310 @code{regs_ever_live}.)\n\
312 On machines that have ``register windows'', the function entry code does\n\
313 not save on the stack the registers that are in the windows, even if\n\
314 they are supposed to be preserved by function calls; instead it takes\n\
315 appropriate steps to ``push'' the register stack, if any non-call-used\n\
316 registers are used in the function.\n\
318 @findex frame_pointer_needed\n\
319 On machines where functions may or may not have frame-pointers, the\n\
320 function entry code must vary accordingly; it must set up the frame\n\
321 pointer if one is wanted, and not otherwise. To determine whether a\n\
322 frame pointer is in wanted, the macro can refer to the variable\n\
323 @code{frame_pointer_needed}. The variable's value will be 1 at run\n\
324 time in a function that needs a frame pointer. @xref{Elimination}.\n\
326 The function entry code is responsible for allocating any stack space\n\
327 required for the function. This stack space consists of the regions\n\
328 listed below. In most cases, these regions are allocated in the\n\
329 order listed, with the last listed region closest to the top of the\n\
330 stack (the lowest address if @code{STACK_GROWS_DOWNWARD} is defined, and\n\
331 the highest address if it is not defined). You can use a different order\n\
332 for a machine if doing so is more convenient or required for\n\
333 compatibility reasons. Except in cases where required by standard\n\
334 or by a debugger, there is no reason why the stack layout used by GCC\n\
335 need agree with that used by other compilers for a machine.",
336 void, (FILE *file, HOST_WIDE_INT size),
337 default_function_pro_epilogue)
339 /* Output the assembler code for end of prologue. */
341 (function_end_prologue,
342 "If defined, a function that outputs assembler code at the end of a\n\
343 prologue. This should be used when the function prologue is being\n\
344 emitted as RTL, and you have some extra assembler that needs to be\n\
345 emitted. @xref{prologue instruction pattern}.",
349 /* Output the assembler code for start of epilogue. */
351 (function_begin_epilogue,
352 "If defined, a function that outputs assembler code at the start of an\n\
353 epilogue. This should be used when the function epilogue is being\n\
354 emitted as RTL, and you have some extra assembler that needs to be\n\
355 emitted. @xref{epilogue instruction pattern}.",
359 /* Output the assembler code for function exit. */
362 "If defined, a function that outputs the assembler code for exit from a\n\
363 function. The epilogue is responsible for restoring the saved\n\
364 registers and stack pointer to their values when the function was\n\
365 called, and returning control to the caller. This macro takes the\n\
366 same arguments as the macro @code{TARGET_ASM_FUNCTION_PROLOGUE}, and the\n\
367 registers to restore are determined from @code{regs_ever_live} and\n\
368 @code{CALL_USED_REGISTERS} in the same way.\n\
370 On some machines, there is a single instruction that does all the work\n\
371 of returning from the function. On these machines, give that\n\
372 instruction the name @samp{return} and do not define the macro\n\
373 @code{TARGET_ASM_FUNCTION_EPILOGUE} at all.\n\
375 Do not define a pattern named @samp{return} if you want the\n\
376 @code{TARGET_ASM_FUNCTION_EPILOGUE} to be used. If you want the target\n\
377 switches to control whether return instructions or epilogues are used,\n\
378 define a @samp{return} pattern with a validity condition that tests the\n\
379 target switches appropriately. If the @samp{return} pattern's validity\n\
380 condition is false, epilogues will be used.\n\
382 On machines where functions may or may not have frame-pointers, the\n\
383 function exit code must vary accordingly. Sometimes the code for these\n\
384 two cases is completely different. To determine whether a frame pointer\n\
385 is wanted, the macro can refer to the variable\n\
386 @code{frame_pointer_needed}. The variable's value will be 1 when compiling\n\
387 a function that needs a frame pointer.\n\
389 Normally, @code{TARGET_ASM_FUNCTION_PROLOGUE} and\n\
390 @code{TARGET_ASM_FUNCTION_EPILOGUE} must treat leaf functions specially.\n\
391 The C variable @code{current_function_is_leaf} is nonzero for such a\n\
392 function. @xref{Leaf Functions}.\n\
394 On some machines, some functions pop their arguments on exit while\n\
395 others leave that for the caller to do. For example, the 68020 when\n\
396 given @option{-mrtd} pops arguments in functions that take a fixed\n\
397 number of arguments.\n\
400 @findex crtl->args.pops_args\n\
401 Your definition of the macro @code{RETURN_POPS_ARGS} decides which\n\
402 functions pop their own arguments. @code{TARGET_ASM_FUNCTION_EPILOGUE}\n\
403 needs to know what was decided. The number of bytes of the current\n\
404 function's arguments that this function should pop is available in\n\
405 @code{crtl->args.pops_args}. @xref{Scalar Return}.",
406 void, (FILE *file, HOST_WIDE_INT size),
407 default_function_pro_epilogue)
409 /* Initialize target-specific sections. */
412 "Define this hook if you need to do something special to set up the\n\
413 @file{varasm.c} sections, or if your target has some special sections\n\
414 of its own that you need to create.\n\
416 GCC calls this hook after processing the command line, but before writing\n\
417 any assembly code, and before calling any of the section-returning hooks\n\
422 /* Tell assembler to change to section NAME with attributes FLAGS.
423 If DECL is non-NULL, it is the VAR_DECL or FUNCTION_DECL with
424 which this section is associated. */
427 "Output assembly directives to switch to section @var{name}. The section\n\
428 should have attributes as specified by @var{flags}, which is a bit mask\n\
429 of the @code{SECTION_*} flags defined in @file{output.h}. If @var{decl}\n\
430 is non-NULL, it is the @code{VAR_DECL} or @code{FUNCTION_DECL} with which\n\
431 this section is associated.",
432 void, (const char *name, unsigned int flags, tree decl),
433 default_no_named_section)
435 /* Return preferred text (sub)section for function DECL.
436 Main purpose of this function is to separate cold, normal and hot
437 functions. STARTUP is true when function is known to be used only
438 at startup (from static constructors or it is main()).
439 EXIT is true when function is known to be used only at exit
440 (from static destructors).
441 Return NULL if function should go to default text section. */
444 "Return preferred text (sub)section for function @var{decl}.\n\
445 Main purpose of this function is to separate cold, normal and hot\n\
446 functions. @var{startup} is true when function is known to be used only\n\
447 at startup (from static constructors or it is @code{main()}).\n\
448 @var{exit} is true when function is known to be used only at exit\n\
449 (from static destructors).\n\
450 Return NULL if function should go to default text section.",
451 section *, (tree decl, enum node_frequency freq, bool startup, bool exit),
452 default_function_section)
454 /* Output the assembler code for function exit. */
456 (function_switched_text_sections,
457 "Used by the target to emit any assembler directives or additional\
458 labels needed when a function is partitioned between different\
459 sections. Output should be written to @var{file}. The function\
460 decl is available as @var{decl} and the new section is `cold' if\
461 @var{new_is_cold} is @code{true}.",
462 void, (FILE *file, tree decl, bool new_is_cold),
463 default_function_switched_text_sections)
465 /* Return a mask describing how relocations should be treated when
466 selecting sections. Bit 1 should be set if global relocations
467 should be placed in a read-write section; bit 0 should be set if
468 local relocations should be placed in a read-write section. */
471 "Return a mask describing how relocations should be treated when\n\
472 selecting sections. Bit 1 should be set if global relocations\n\
473 should be placed in a read-write section; bit 0 should be set if\n\
474 local relocations should be placed in a read-write section.\n\
476 The default version of this function returns 3 when @option{-fpic}\n\
477 is in effect, and 0 otherwise. The hook is typically redefined\n\
478 when the target cannot support (some kinds of) dynamic relocations\n\
479 in read-only sections even in executables.",
481 default_reloc_rw_mask)
483 /* Return a section for EXP. It may be a DECL or a constant. RELOC
484 is nonzero if runtime relocations must be applied; bit 1 will be
485 set if the runtime relocations require non-local name resolution.
486 ALIGN is the required alignment of the data. */
489 "Return the section into which @var{exp} should be placed. You can\n\
490 assume that @var{exp} is either a @code{VAR_DECL} node or a constant of\n\
491 some sort. @var{reloc} indicates whether the initial value of @var{exp}\n\
492 requires link-time relocations. Bit 0 is set when variable contains\n\
493 local relocations only, while bit 1 is set for global relocations.\n\
494 @var{align} is the constant alignment in bits.\n\
496 The default version of this function takes care of putting read-only\n\
497 variables in @code{readonly_data_section}.\n\
499 See also @var{USE_SELECT_SECTION_FOR_FUNCTIONS}.",
500 section *, (tree exp, int reloc, unsigned HOST_WIDE_INT align),
501 default_select_section)
503 /* Return a section for X. MODE is X's mode and ALIGN is its
504 alignment in bits. */
507 "Return the section into which a constant @var{x}, of mode @var{mode},\n\
508 should be placed. You can assume that @var{x} is some kind of\n\
509 constant in RTL@. The argument @var{mode} is redundant except in the\n\
510 case of a @code{const_int} rtx. @var{align} is the constant alignment\n\
513 The default version of this function takes care of putting symbolic\n\
514 constants in @code{flag_pic} mode in @code{data_section} and everything\n\
515 else in @code{readonly_data_section}.",
516 section *, (machine_mode mode, rtx x, unsigned HOST_WIDE_INT align),
517 default_select_rtx_section)
519 /* Select a unique section name for DECL. RELOC is the same as
520 for SELECT_SECTION. */
523 "Build up a unique section name, expressed as a @code{STRING_CST} node,\n\
524 and assign it to @samp{DECL_SECTION_NAME (@var{decl})}.\n\
525 As with @code{TARGET_ASM_SELECT_SECTION}, @var{reloc} indicates whether\n\
526 the initial value of @var{exp} requires link-time relocations.\n\
528 The default version of this function appends the symbol name to the\n\
529 ELF section name that would normally be used for the symbol. For\n\
530 example, the function @code{foo} would be placed in @code{.text.foo}.\n\
531 Whatever the actual target object format, this is often good enough.",
532 void, (tree decl, int reloc),
533 default_unique_section)
535 /* Return the readonly data section associated with function DECL. */
537 (function_rodata_section,
538 "Return the readonly data section associated with\n\
539 @samp{DECL_SECTION_NAME (@var{decl})}.\n\
540 The default version of this function selects @code{.gnu.linkonce.r.name} if\n\
541 the function's section is @code{.gnu.linkonce.t.name}, @code{.rodata.name}\n\
542 if function is in @code{.text.name}, and the normal readonly-data section\n\
544 section *, (tree decl),
545 default_function_rodata_section)
547 /* Nonnull if the target wants to override the default ".rodata" prefix
548 for mergeable data sections. */
550 (mergeable_rodata_prefix,
551 "Usually, the compiler uses the prefix @code{\".rodata\"} to construct\n\
552 section names for mergeable constant data. Define this macro to override\n\
553 the string if a different section name should be used.",
554 const char *, ".rodata")
556 /* Return the section to be used for transactional memory clone tables. */
558 (tm_clone_table_section,
559 "Return the section that should be used for transactional memory clone\
561 section *, (void), default_clone_table_section)
563 /* Output a constructor for a symbol with a given priority. */
566 "If defined, a function that outputs assembler code to arrange to call\n\
567 the function referenced by @var{symbol} at initialization time.\n\
569 Assume that @var{symbol} is a @code{SYMBOL_REF} for a function taking\n\
570 no arguments and with no return value. If the target supports initialization\n\
571 priorities, @var{priority} is a value between 0 and @code{MAX_INIT_PRIORITY};\n\
572 otherwise it must be @code{DEFAULT_INIT_PRIORITY}.\n\
574 If this macro is not defined by the target, a suitable default will\n\
575 be chosen if (1) the target supports arbitrary section names, (2) the\n\
576 target defines @code{CTORS_SECTION_ASM_OP}, or (3) @code{USE_COLLECT2}\n\
578 void, (rtx symbol, int priority), NULL)
580 /* Output a destructor for a symbol with a given priority. */
583 "This is like @code{TARGET_ASM_CONSTRUCTOR} but used for termination\n\
584 functions rather than initialization functions.",
585 void, (rtx symbol, int priority), NULL)
587 /* Output the assembler code for a thunk function. THUNK_DECL is the
588 declaration for the thunk function itself, FUNCTION is the decl for
589 the target function. DELTA is an immediate constant offset to be
590 added to THIS. If VCALL_OFFSET is nonzero, the word at
591 *(*this + vcall_offset) should be added to THIS. */
594 "A function that outputs the assembler code for a thunk\n\
595 function, used to implement C++ virtual function calls with multiple\n\
596 inheritance. The thunk acts as a wrapper around a virtual function,\n\
597 adjusting the implicit object parameter before handing control off to\n\
598 the real function.\n\
600 First, emit code to add the integer @var{delta} to the location that\n\
601 contains the incoming first argument. Assume that this argument\n\
602 contains a pointer, and is the one used to pass the @code{this} pointer\n\
603 in C++. This is the incoming argument @emph{before} the function prologue,\n\
604 e.g.@: @samp{%o0} on a sparc. The addition must preserve the values of\n\
605 all other incoming arguments.\n\
607 Then, if @var{vcall_offset} is nonzero, an additional adjustment should be\n\
608 made after adding @code{delta}. In particular, if @var{p} is the\n\
609 adjusted pointer, the following adjustment should be made:\n\
612 p += (*((ptrdiff_t **)p))[vcall_offset/sizeof(ptrdiff_t)]\n\
615 After the additions, emit code to jump to @var{function}, which is a\n\
616 @code{FUNCTION_DECL}. This is a direct pure jump, not a call, and does\n\
617 not touch the return address. Hence returning from @var{FUNCTION} will\n\
618 return to whoever called the current @samp{thunk}.\n\
620 The effect must be as if @var{function} had been called directly with\n\
621 the adjusted first argument. This macro is responsible for emitting all\n\
622 of the code for a thunk function; @code{TARGET_ASM_FUNCTION_PROLOGUE}\n\
623 and @code{TARGET_ASM_FUNCTION_EPILOGUE} are not invoked.\n\
625 The @var{thunk_fndecl} is redundant. (@var{delta} and @var{function}\n\
626 have already been extracted from it.) It might possibly be useful on\n\
627 some targets, but probably not.\n\
629 If you do not define this macro, the target-independent code in the C++\n\
630 front end will generate a less efficient heavyweight thunk that calls\n\
631 @var{function} instead of jumping to it. The generic approach does\n\
632 not support varargs.",
633 void, (FILE *file, tree thunk_fndecl, HOST_WIDE_INT delta,
634 HOST_WIDE_INT vcall_offset, tree function),
637 /* Determine whether output_mi_thunk would succeed. */
638 /* ??? Ideally, this hook would not exist, and success or failure
639 would be returned from output_mi_thunk directly. But there's
640 too much undo-able setup involved in invoking output_mi_thunk.
641 Could be fixed by making output_mi_thunk emit rtl instead of
642 text to the output file. */
644 (can_output_mi_thunk,
645 "A function that returns true if TARGET_ASM_OUTPUT_MI_THUNK would be able\n\
646 to output the assembler code for the thunk function specified by the\n\
647 arguments it is passed, and false otherwise. In the latter case, the\n\
648 generic approach will be used by the C++ front end, with the limitations\n\
649 previously exposed.",
650 bool, (const_tree thunk_fndecl, HOST_WIDE_INT delta,
651 HOST_WIDE_INT vcall_offset, const_tree function),
652 hook_bool_const_tree_hwi_hwi_const_tree_false)
654 /* Output any boilerplate text needed at the beginning of a
658 "Output to @code{asm_out_file} any text which the assembler expects to\n\
659 find at the beginning of a file. The default behavior is controlled\n\
660 by two flags, documented below. Unless your target's assembler is\n\
661 quite unusual, if you override the default, you should call\n\
662 @code{default_file_start} at some point in your target hook. This\n\
663 lets other target files rely on these variables.",
667 /* Output any boilerplate text needed at the end of a translation unit. */
670 "Output to @code{asm_out_file} any text which the assembler expects\n\
671 to find at the end of a file. The default is to output nothing.",
675 /* Output any boilerplate text needed at the beginning of an
676 LTO output stream. */
679 "Output to @code{asm_out_file} any text which the assembler expects\n\
680 to find at the start of an LTO section. The default is to output\n\
685 /* Output any boilerplate text needed at the end of an
686 LTO output stream. */
689 "Output to @code{asm_out_file} any text which the assembler expects\n\
690 to find at the end of an LTO section. The default is to output\n\
695 /* Output any boilerplace text needed at the end of a
696 translation unit before debug and unwind info is emitted. */
699 "Output to @code{asm_out_file} any text which is needed before emitting\n\
700 unwind info and debug info at the end of a file. Some targets emit\n\
701 here PIC setup thunks that cannot be emitted at the end of file,\n\
702 because they couldn't have unwind info then. The default is to output\n\
707 /* Output an assembler pseudo-op to declare a library function name
711 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
712 pseudo-op to declare a library function name external. The name of the\n\
713 library function is given by @var{symref}, which is a @code{symbol_ref}.",
715 default_external_libcall)
717 /* Output an assembler directive to mark decl live. This instructs
718 linker to not dead code strip this symbol. */
720 (mark_decl_preserved,
721 "This target hook is a function to output to @var{asm_out_file} an assembler\n\
722 directive to annotate @var{symbol} as used. The Darwin target uses the\n\
723 .no_dead_code_strip directive.",
724 void, (const char *symbol),
725 hook_void_constcharptr)
727 /* Output a record of the command line switches that have been passed. */
729 (record_gcc_switches,
730 "Provides the target with the ability to record the gcc command line\n\
731 switches that have been passed to the compiler, and options that are\n\
732 enabled. The @var{type} argument specifies what is being recorded.\n\
733 It can take the following values:\n\
736 @item SWITCH_TYPE_PASSED\n\
737 @var{text} is a command line switch that has been set by the user.\n\
739 @item SWITCH_TYPE_ENABLED\n\
740 @var{text} is an option which has been enabled. This might be as a\n\
741 direct result of a command line switch, or because it is enabled by\n\
742 default or because it has been enabled as a side effect of a different\n\
743 command line switch. For example, the @option{-O2} switch enables\n\
744 various different individual optimization passes.\n\
746 @item SWITCH_TYPE_DESCRIPTIVE\n\
747 @var{text} is either NULL or some descriptive text which should be\n\
748 ignored. If @var{text} is NULL then it is being used to warn the\n\
749 target hook that either recording is starting or ending. The first\n\
750 time @var{type} is SWITCH_TYPE_DESCRIPTIVE and @var{text} is NULL, the\n\
751 warning is for start up and the second time the warning is for\n\
752 wind down. This feature is to allow the target hook to make any\n\
753 necessary preparations before it starts to record switches and to\n\
754 perform any necessary tidying up after it has finished recording\n\
757 @item SWITCH_TYPE_LINE_START\n\
758 This option can be ignored by this target hook.\n\
760 @item SWITCH_TYPE_LINE_END\n\
761 This option can be ignored by this target hook.\n\
764 The hook's return value must be zero. Other return values may be\n\
765 supported in the future.\n\
767 By default this hook is set to NULL, but an example implementation is\n\
768 provided for ELF based targets. Called @var{elf_record_gcc_switches},\n\
769 it records the switches as ASCII text inside a new, string mergeable\n\
770 section in the assembler output file. The name of the new section is\n\
771 provided by the @code{TARGET_ASM_RECORD_GCC_SWITCHES_SECTION} target\n\
773 int, (print_switch_type type, const char *text),
776 /* The name of the section that the example ELF implementation of
777 record_gcc_switches will use to store the information. Target
778 specific versions of record_gcc_switches may or may not use
781 (record_gcc_switches_section,
782 "This is the name of the section that will be created by the example\n\
783 ELF implementation of the @code{TARGET_ASM_RECORD_GCC_SWITCHES} target\n\
785 const char *, ".GCC.command.line")
787 /* Output the definition of a section anchor. */
790 "Write the assembly code to define section anchor @var{x}, which is a\n\
791 @code{SYMBOL_REF} for which @samp{SYMBOL_REF_ANCHOR_P (@var{x})} is true.\n\
792 The hook is called with the assembly output position set to the beginning\n\
793 of @code{SYMBOL_REF_BLOCK (@var{x})}.\n\
795 If @code{ASM_OUTPUT_DEF} is available, the hook's default definition uses\n\
796 it to define the symbol as @samp{. + SYMBOL_REF_BLOCK_OFFSET (@var{x})}.\n\
797 If @code{ASM_OUTPUT_DEF} is not available, the hook's default definition\n\
798 is @code{NULL}, which disables the use of section anchors altogether.",
800 default_asm_output_anchor)
804 "Output a string based on @var{name}, suitable for the @samp{#ident} \
805 directive, or the equivalent directive or pragma in non-C-family languages. \
806 If this hook is not defined, nothing is output for the @samp{#ident} \
808 void, (const char *name),
809 hook_void_constcharptr)
811 /* Output a DTP-relative reference to a TLS symbol. */
813 (output_dwarf_dtprel,
814 "If defined, this target hook is a function which outputs a DTP-relative\n\
815 reference to the given TLS symbol of the specified size.",
816 void, (FILE *file, int size, rtx x),
819 /* Some target machines need to postscan each insn after it is output. */
821 (final_postscan_insn,
822 "If defined, this target hook is a function which is executed just after the\n\
823 output of assembler code for @var{insn}, to change the mode of the assembler\n\
826 Here the argument @var{opvec} is the vector containing the operands\n\
827 extracted from @var{insn}, and @var{noperands} is the number of\n\
828 elements of the vector which contain meaningful data for this insn.\n\
829 The contents of this vector are what was used to convert the insn\n\
830 template into assembler code, so you can change the assembler mode\n\
831 by checking the contents of the vector.",
832 void, (FILE *file, rtx_insn *insn, rtx *opvec, int noperands),
835 /* Emit the trampoline template. This hook may be NULL. */
837 (trampoline_template,
838 "This hook is called by @code{assemble_trampoline_template} to output,\n\
839 on the stream @var{f}, assembler code for a block of data that contains\n\
840 the constant parts of a trampoline. This code should not include a\n\
841 label---the label is taken care of automatically.\n\
843 If you do not define this hook, it means no template is needed\n\
844 for the target. Do not define this hook on systems where the block move\n\
845 code to copy the trampoline into place would be larger than the code\n\
846 to generate it on the spot.",
851 (output_source_filename,
852 "Output COFF information or DWARF debugging information which indicates\
853 that filename @var{name} is the current source file to the stdio\
854 stream @var{file}.\n\
856 This target hook need not be defined if the standard form of output\
857 for the file format in use is appropriate.",
858 void ,(FILE *file, const char *name),
859 default_asm_output_source_filename)
862 (output_addr_const_extra,
863 "A target hook to recognize @var{rtx} patterns that @code{output_addr_const}\n\
864 can't deal with, and output assembly code to @var{file} corresponding to\n\
865 the pattern @var{x}. This may be used to allow machine-dependent\n\
866 @code{UNSPEC}s to appear within constants.\n\
868 If target hook fails to recognize a pattern, it must return @code{false},\n\
869 so that a standard error message is printed. If it prints an error message\n\
870 itself, by calling, for example, @code{output_operand_lossage}, it may just\n\
871 return @code{true}.",
872 bool, (FILE *file, rtx x),
873 hook_bool_FILEptr_rtx_false)
875 /* ??? The TARGET_PRINT_OPERAND* hooks are part of the asm_out struct,
876 even though that is not reflected in the macro name to override their
879 #define HOOK_PREFIX "TARGET_"
881 /* Emit a machine-specific insn operand. */
882 /* ??? tm.texi only documents the old macro PRINT_OPERAND,
883 not this hook, and uses a different name for the argument FILE. */
887 void, (FILE *file, rtx x, int code),
888 default_print_operand)
890 /* Emit a machine-specific memory address. */
891 /* ??? tm.texi only documents the old macro PRINT_OPERAND_ADDRESS,
892 not this hook, and uses different argument names. */
894 (print_operand_address,
896 void, (FILE *file, rtx addr),
897 default_print_operand_address)
899 /* Determine whether CODE is a valid punctuation character for the
900 `print_operand' hook. */
901 /* ??? tm.texi only documents the old macro PRINT_OPERAND_PUNCT_VALID_P,
904 (print_operand_punct_valid_p,
906 bool ,(unsigned char code),
907 default_print_operand_punct_valid_p)
909 /* Given a symbol name, perform same mangling as assemble_name and
910 ASM_OUTPUT_LABELREF, returning result as an IDENTIFIER_NODE. */
912 (mangle_assembler_name,
913 "Given a symbol @var{name}, perform same mangling as @code{varasm.c}'s\
914 @code{assemble_name}, but in memory rather than to a file stream, returning\
915 result as an @code{IDENTIFIER_NODE}. Required for correct LTO symtabs. The\
916 default implementation calls the @code{TARGET_STRIP_NAME_ENCODING} hook and\
917 then prepends the @code{USER_LABEL_PREFIX}, if any.",
918 tree, (const char *name),
919 default_mangle_assembler_name)
921 HOOK_VECTOR_END (asm_out)
923 /* Functions relating to instruction scheduling. All of these
924 default to null pointers, which haifa-sched.c looks for and handles. */
926 #define HOOK_PREFIX "TARGET_SCHED_"
927 HOOK_VECTOR (TARGET_SCHED, sched)
929 /* Given the current cost, COST, of an insn, INSN, calculate and
930 return a new cost based on its relationship to DEP_INSN through
931 the dependence LINK. The default is to make no adjustment. */
934 "This function corrects the value of @var{cost} based on the\n\
935 relationship between @var{insn} and @var{dep_insn} through the\n\
936 dependence @var{link}. It should return the new value. The default\n\
937 is to make no adjustment to @var{cost}. This can be used for example\n\
938 to specify to the scheduler using the traditional pipeline description\n\
939 that an output- or anti-dependence does not incur the same cost as a\n\
940 data-dependence. If the scheduler using the automaton based pipeline\n\
941 description, the cost of anti-dependence is zero and the cost of\n\
942 output-dependence is maximum of one and the difference of latency\n\
943 times of the first and the second insns. If these values are not\n\
944 acceptable, you could use the hook to modify them too. See also\n\
945 @pxref{Processor pipeline description}.",
946 int, (rtx_insn *insn, rtx link, rtx_insn *dep_insn, int cost), NULL)
948 /* Adjust the priority of an insn as you see fit. Returns the new priority. */
951 "This hook adjusts the integer scheduling priority @var{priority} of\n\
952 @var{insn}. It should return the new priority. Increase the priority to\n\
953 execute @var{insn} earlier, reduce the priority to execute @var{insn}\n\
954 later. Do not define this hook if you do not need to adjust the\n\
955 scheduling priorities of insns.",
956 int, (rtx_insn *insn, int priority), NULL)
958 /* Function which returns the maximum number of insns that can be
959 scheduled in the same machine cycle. This must be constant
960 over an entire compilation. The default is 1. */
963 "This hook returns the maximum number of instructions that can ever\n\
964 issue at the same time on the target machine. The default is one.\n\
965 Although the insn scheduler can define itself the possibility of issue\n\
966 an insn on the same cycle, the value can serve as an additional\n\
967 constraint to issue insns on the same simulated processor cycle (see\n\
968 hooks @samp{TARGET_SCHED_REORDER} and @samp{TARGET_SCHED_REORDER2}).\n\
969 This value must be constant over the entire compilation. If you need\n\
970 it to vary depending on what the instructions are, you must use\n\
971 @samp{TARGET_SCHED_VARIABLE_ISSUE}.",
974 /* Calculate how much this insn affects how many more insns we
975 can emit this cycle. Default is they all cost the same. */
978 "This hook is executed by the scheduler after it has scheduled an insn\n\
979 from the ready list. It should return the number of insns which can\n\
980 still be issued in the current cycle. The default is\n\
981 @samp{@w{@var{more} - 1}} for insns other than @code{CLOBBER} and\n\
982 @code{USE}, which normally are not counted against the issue rate.\n\
983 You should define this hook if some insns take more machine resources\n\
984 than others, so that fewer insns can follow them in the same cycle.\n\
985 @var{file} is either a null pointer, or a stdio stream to write any\n\
986 debug output to. @var{verbose} is the verbose level provided by\n\
987 @option{-fsched-verbose-@var{n}}. @var{insn} is the instruction that\n\
989 int, (FILE *file, int verbose, rtx_insn *insn, int more), NULL)
991 /* Initialize machine-dependent scheduling code. */
994 "This hook is executed by the scheduler at the beginning of each block of\n\
995 instructions that are to be scheduled. @var{file} is either a null\n\
996 pointer, or a stdio stream to write any debug output to. @var{verbose}\n\
997 is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
998 @var{max_ready} is the maximum number of insns in the current scheduling\n\
999 region that can be live at the same time. This can be used to allocate\n\
1000 scratch space if it is needed, e.g.@: by @samp{TARGET_SCHED_REORDER}.",
1001 void, (FILE *file, int verbose, int max_ready), NULL)
1003 /* Finalize machine-dependent scheduling code. */
1006 "This hook is executed by the scheduler at the end of each block of\n\
1007 instructions that are to be scheduled. It can be used to perform\n\
1008 cleanup of any actions done by the other scheduling hooks. @var{file}\n\
1009 is either a null pointer, or a stdio stream to write any debug output\n\
1010 to. @var{verbose} is the verbose level provided by\n\
1011 @option{-fsched-verbose-@var{n}}.",
1012 void, (FILE *file, int verbose), NULL)
1014 /* Initialize machine-dependent function wide scheduling code. */
1017 "This hook is executed by the scheduler after function level initializations.\n\
1018 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1019 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.\n\
1020 @var{old_max_uid} is the maximum insn uid when scheduling begins.",
1021 void, (FILE *file, int verbose, int old_max_uid), NULL)
1023 /* Finalize machine-dependent function wide scheduling code. */
1026 "This is the cleanup hook corresponding to @code{TARGET_SCHED_INIT_GLOBAL}.\n\
1027 @var{file} is either a null pointer, or a stdio stream to write any debug output to.\n\
1028 @var{verbose} is the verbose level provided by @option{-fsched-verbose-@var{n}}.",
1029 void, (FILE *file, int verbose), NULL)
1031 /* Reorder insns in a machine-dependent fashion, in two different
1032 places. Default does nothing. */
1035 "This hook is executed by the scheduler after it has scheduled the ready\n\
1036 list, to allow the machine description to reorder it (for example to\n\
1037 combine two small instructions together on @samp{VLIW} machines).\n\
1038 @var{file} is either a null pointer, or a stdio stream to write any\n\
1039 debug output to. @var{verbose} is the verbose level provided by\n\
1040 @option{-fsched-verbose-@var{n}}. @var{ready} is a pointer to the ready\n\
1041 list of instructions that are ready to be scheduled. @var{n_readyp} is\n\
1042 a pointer to the number of elements in the ready list. The scheduler\n\
1043 reads the ready list in reverse order, starting with\n\
1044 @var{ready}[@var{*n_readyp} @minus{} 1] and going to @var{ready}[0]. @var{clock}\n\
1045 is the timer tick of the scheduler. You may modify the ready list and\n\
1046 the number of ready insns. The return value is the number of insns that\n\
1047 can issue this cycle; normally this is just @code{issue_rate}. See also\n\
1048 @samp{TARGET_SCHED_REORDER2}.",
1049 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1053 "Like @samp{TARGET_SCHED_REORDER}, but called at a different time. That\n\
1054 function is called whenever the scheduler starts a new cycle. This one\n\
1055 is called once per iteration over a cycle, immediately after\n\
1056 @samp{TARGET_SCHED_VARIABLE_ISSUE}; it can reorder the ready list and\n\
1057 return the number of insns to be scheduled in the same cycle. Defining\n\
1058 this hook can be useful if there are frequent situations where\n\
1059 scheduling one insn causes other insns to become ready in the same\n\
1060 cycle. These other insns can then be taken into account properly.",
1061 int, (FILE *file, int verbose, rtx_insn **ready, int *n_readyp, int clock), NULL)
1065 "This hook is used to check whether target platform supports macro fusion.",
1069 (macro_fusion_pair_p,
1070 "This hook is used to check whether two insns should be macro fused for\n\
1071 a target microarchitecture. If this hook returns true for the given insn pair\n\
1072 (@var{prev} and @var{curr}), the scheduler will put them into a sched\n\
1073 group, and they will not be scheduled apart. The two insns will be either\n\
1074 two SET insns or a compare and a conditional jump and this hook should\n\
1075 validate any dependencies needed to fuse the two insns together.",
1076 bool, (rtx_insn *prev, rtx_insn *curr), NULL)
1078 /* The following member value is a pointer to a function called
1079 after evaluation forward dependencies of insns in chain given
1080 by two parameter values (head and tail correspondingly). */
1082 (dependencies_evaluation_hook,
1083 "This hook is called after evaluation forward dependencies of insns in\n\
1084 chain given by two parameter values (@var{head} and @var{tail}\n\
1085 correspondingly) but before insns scheduling of the insn chain. For\n\
1086 example, it can be used for better insn classification if it requires\n\
1087 analysis of dependencies. This hook can use backward and forward\n\
1088 dependencies of the insn scheduler because they are already\n\
1090 void, (rtx_insn *head, rtx_insn *tail), NULL)
1092 /* The values of the following four members are pointers to functions
1093 used to simplify the automaton descriptions. dfa_pre_cycle_insn and
1094 dfa_post_cycle_insn give functions returning insns which are used to
1095 change the pipeline hazard recognizer state when the new simulated
1096 processor cycle correspondingly starts and finishes. The function
1097 defined by init_dfa_pre_cycle_insn and init_dfa_post_cycle_insn are
1098 used to initialize the corresponding insns. The default values of
1099 the members result in not changing the automaton state when the
1100 new simulated processor cycle correspondingly starts and finishes. */
1103 (init_dfa_pre_cycle_insn,
1104 "The hook can be used to initialize data used by the previous hook.",
1108 (dfa_pre_cycle_insn,
1109 "The hook returns an RTL insn. The automaton state used in the\n\
1110 pipeline hazard recognizer is changed as if the insn were scheduled\n\
1111 when the new simulated processor cycle starts. Usage of the hook may\n\
1112 simplify the automaton pipeline description for some @acronym{VLIW}\n\
1113 processors. If the hook is defined, it is used only for the automaton\n\
1114 based pipeline description. The default is not to change the state\n\
1115 when the new simulated processor cycle starts.",
1119 (init_dfa_post_cycle_insn,
1120 "The hook is analogous to @samp{TARGET_SCHED_INIT_DFA_PRE_CYCLE_INSN} but\n\
1121 used to initialize data used by the previous hook.",
1125 (dfa_post_cycle_insn,
1126 "The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1127 to changed the state as if the insn were scheduled when the new\n\
1128 simulated processor cycle finishes.",
1129 rtx_insn *, (void), NULL)
1131 /* The values of the following two members are pointers to
1132 functions used to simplify the automaton descriptions.
1133 dfa_pre_advance_cycle and dfa_post_advance_cycle are getting called
1134 immediately before and after cycle is advanced. */
1137 (dfa_pre_advance_cycle,
1138 "The hook to notify target that the current simulated cycle is about to finish.\n\
1139 The hook is analogous to @samp{TARGET_SCHED_DFA_PRE_CYCLE_INSN} but used\n\
1140 to change the state in more complicated situations - e.g., when advancing\n\
1141 state on a single insn is not enough.",
1145 (dfa_post_advance_cycle,
1146 "The hook to notify target that new simulated cycle has just started.\n\
1147 The hook is analogous to @samp{TARGET_SCHED_DFA_POST_CYCLE_INSN} but used\n\
1148 to change the state in more complicated situations - e.g., when advancing\n\
1149 state on a single insn is not enough.",
1152 /* The following member value is a pointer to a function returning value
1153 which defines how many insns in queue `ready' will we try for
1154 multi-pass scheduling. If the member value is nonzero and the
1155 function returns positive value, the DFA based scheduler will make
1156 multi-pass scheduling for the first cycle. In other words, we will
1157 try to choose ready insn which permits to start maximum number of
1158 insns on the same cycle. */
1160 (first_cycle_multipass_dfa_lookahead,
1161 "This hook controls better choosing an insn from the ready insn queue\n\
1162 for the @acronym{DFA}-based insn scheduler. Usually the scheduler\n\
1163 chooses the first insn from the queue. If the hook returns a positive\n\
1164 value, an additional scheduler code tries all permutations of\n\
1165 @samp{TARGET_SCHED_FIRST_CYCLE_MULTIPASS_DFA_LOOKAHEAD ()}\n\
1166 subsequent ready insns to choose an insn whose issue will result in\n\
1167 maximal number of issued insns on the same cycle. For the\n\
1168 @acronym{VLIW} processor, the code could actually solve the problem of\n\
1169 packing simple insns into the @acronym{VLIW} insn. Of course, if the\n\
1170 rules of @acronym{VLIW} packing are described in the automaton.\n\
1172 This code also could be used for superscalar @acronym{RISC}\n\
1173 processors. Let us consider a superscalar @acronym{RISC} processor\n\
1174 with 3 pipelines. Some insns can be executed in pipelines @var{A} or\n\
1175 @var{B}, some insns can be executed only in pipelines @var{B} or\n\
1176 @var{C}, and one insn can be executed in pipeline @var{B}. The\n\
1177 processor may issue the 1st insn into @var{A} and the 2nd one into\n\
1178 @var{B}. In this case, the 3rd insn will wait for freeing @var{B}\n\
1179 until the next cycle. If the scheduler issues the 3rd insn the first,\n\
1180 the processor could issue all 3 insns per cycle.\n\
1182 Actually this code demonstrates advantages of the automaton based\n\
1183 pipeline hazard recognizer. We try quickly and easy many insn\n\
1184 schedules to choose the best one.\n\
1186 The default is no multipass scheduling.",
1189 /* The following member value is pointer to a function controlling
1190 what insns from the ready insn queue will be considered for the
1191 multipass insn scheduling. If the hook returns zero for insn
1192 passed as the parameter, the insn will be not chosen to be issued. */
1194 (first_cycle_multipass_dfa_lookahead_guard,
1196 This hook controls what insns from the ready insn queue will be\n\
1197 considered for the multipass insn scheduling. If the hook returns\n\
1198 zero for @var{insn}, the insn will be considered in multipass scheduling.\n\
1199 Positive return values will remove @var{insn} from consideration on\n\
1200 the current round of multipass scheduling.\n\
1201 Negative return values will remove @var{insn} from consideration for given\n\
1202 number of cycles.\n\
1203 Backends should be careful about returning non-zero for highest priority\n\
1204 instruction at position 0 in the ready list. @var{ready_index} is passed\n\
1205 to allow backends make correct judgements.\n\
1207 The default is that any ready insns can be chosen to be issued.",
1208 int, (rtx_insn *insn, int ready_index), NULL)
1210 /* This hook prepares the target for a new round of multipass
1212 DATA is a pointer to target-specific data used for multipass scheduling.
1213 READY_TRY and N_READY represent the current state of search in the
1214 optimization space. The target can filter out instructions that
1215 should not be tried during current round by setting corresponding
1216 elements in READY_TRY to non-zero.
1217 FIRST_CYCLE_INSN_P is true if this is the first round of multipass
1218 scheduling on current cycle. */
1220 (first_cycle_multipass_begin,
1221 "This hook prepares the target backend for a new round of multipass\n\
1223 void, (void *data, signed char *ready_try, int n_ready, bool first_cycle_insn_p),
1226 /* This hook is called when multipass scheduling evaluates instruction INSN.
1227 DATA is a pointer to target-specific data that can be used to record effects
1228 of INSN on CPU that are not described in DFA.
1229 READY_TRY and N_READY represent the current state of search in the
1230 optimization space. The target can filter out instructions that
1231 should not be tried after issuing INSN by setting corresponding
1232 elements in READY_TRY to non-zero.
1233 INSN is the instruction being evaluated.
1234 PREV_DATA is a pointer to target-specific data corresponding
1235 to a state before issuing INSN. */
1237 (first_cycle_multipass_issue,
1238 "This hook is called when multipass scheduling evaluates instruction INSN.",
1239 void, (void *data, signed char *ready_try, int n_ready, rtx_insn *insn,
1240 const void *prev_data), NULL)
1242 /* This hook is called when multipass scheduling backtracks from evaluation of
1243 instruction corresponding to DATA.
1244 DATA is a pointer to target-specific data that stores the effects
1245 of instruction from which the algorithm backtracks on CPU that are not
1247 READY_TRY and N_READY represent the current state of search in the
1248 optimization space. The target can filter out instructions that
1249 should not be tried after issuing INSN by setting corresponding
1250 elements in READY_TRY to non-zero. */
1252 (first_cycle_multipass_backtrack,
1253 "This is called when multipass scheduling backtracks from evaluation of\n\
1255 void, (const void *data, signed char *ready_try, int n_ready), NULL)
1257 /* This hook notifies the target about the result of the concluded current
1258 round of multipass scheduling.
1260 If DATA is non-NULL it points to target-specific data used for multipass
1261 scheduling which corresponds to instruction at the start of the chain of
1262 the winning solution. DATA is NULL when multipass scheduling cannot find
1263 a good enough solution on current cycle and decides to retry later,
1264 usually after advancing the cycle count. */
1266 (first_cycle_multipass_end,
1267 "This hook notifies the target about the result of the concluded current\n\
1268 round of multipass scheduling.",
1269 void, (const void *data), NULL)
1271 /* This hook is called to initialize target-specific data for multipass
1272 scheduling after it has been allocated.
1273 DATA is a pointer to target-specific data that stores the effects
1274 of instruction from which the algorithm backtracks on CPU that are not
1275 described in DFA. */
1277 (first_cycle_multipass_init,
1278 "This hook initializes target-specific data used in multipass scheduling.",
1279 void, (void *data), NULL)
1281 /* This hook is called to finalize target-specific data for multipass
1282 scheduling before it is deallocated.
1283 DATA is a pointer to target-specific data that stores the effects
1284 of instruction from which the algorithm backtracks on CPU that are not
1285 described in DFA. */
1287 (first_cycle_multipass_fini,
1288 "This hook finalizes target-specific data used in multipass scheduling.",
1289 void, (void *data), NULL)
1291 /* The following member value is pointer to a function called by
1292 the insn scheduler before issuing insn passed as the third
1293 parameter on given cycle. If the hook returns nonzero, the
1294 insn is not issued on given processors cycle. Instead of that,
1295 the processor cycle is advanced. If the value passed through
1296 the last parameter is zero, the insn ready queue is not sorted
1297 on the new cycle start as usually. The first parameter passes
1298 file for debugging output. The second one passes the scheduler
1299 verbose level of the debugging output. The forth and the fifth
1300 parameter values are correspondingly processor cycle on which
1301 the previous insn has been issued and the current processor cycle. */
1304 "This hook is called by the insn scheduler before issuing @var{insn}\n\
1305 on cycle @var{clock}. If the hook returns nonzero,\n\
1306 @var{insn} is not issued on this processor cycle. Instead,\n\
1307 the processor cycle is advanced. If *@var{sort_p}\n\
1308 is zero, the insn ready queue is not sorted on the new cycle\n\
1309 start as usually. @var{dump} and @var{verbose} specify the file and\n\
1310 verbosity level to use for debugging output.\n\
1311 @var{last_clock} and @var{clock} are, respectively, the\n\
1312 processor cycle on which the previous insn has been issued,\n\
1313 and the current processor cycle.",
1314 int, (FILE *dump, int verbose, rtx_insn *insn, int last_clock,
1315 int clock, int *sort_p),
1318 /* The following member value is a pointer to a function called by the
1319 insn scheduler. It should return true if there exists a dependence
1320 which is considered costly by the target, between the insn
1321 DEP_PRO (&_DEP), and the insn DEP_CON (&_DEP). The first parameter is
1322 the dep that represents the dependence between the two insns. The
1323 second argument is the cost of the dependence as estimated by
1324 the scheduler. The last argument is the distance in cycles
1325 between the already scheduled insn (first parameter) and the
1326 second insn (second parameter). */
1328 (is_costly_dependence,
1329 "This hook is used to define which dependences are considered costly by\n\
1330 the target, so costly that it is not advisable to schedule the insns that\n\
1331 are involved in the dependence too close to one another. The parameters\n\
1332 to this hook are as follows: The first parameter @var{_dep} is the dependence\n\
1333 being evaluated. The second parameter @var{cost} is the cost of the\n\
1334 dependence as estimated by the scheduler, and the third\n\
1335 parameter @var{distance} is the distance in cycles between the two insns.\n\
1336 The hook returns @code{true} if considering the distance between the two\n\
1337 insns the dependence between them is considered costly by the target,\n\
1338 and @code{false} otherwise.\n\
1340 Defining this hook can be useful in multiple-issue out-of-order machines,\n\
1341 where (a) it's practically hopeless to predict the actual data/resource\n\
1342 delays, however: (b) there's a better chance to predict the actual grouping\n\
1343 that will be formed, and (c) correctly emulating the grouping can be very\n\
1344 important. In such targets one may want to allow issuing dependent insns\n\
1345 closer to one another---i.e., closer than the dependence distance; however,\n\
1346 not in cases of ``costly dependences'', which this hooks allows to define.",
1347 bool, (struct _dep *_dep, int cost, int distance), NULL)
1351 "Given the current cost, @var{cost}, of an insn, @var{insn}, calculate and\
1352 return a new cost based on its relationship to @var{dep_insn} through the\
1353 dependence of weakness @var{dw}. The default is to make no adjustment.",
1354 int, (rtx_insn *insn, int dep_type1, rtx_insn *dep_insn, int cost,
1358 /* The following member value is a pointer to a function called
1359 by the insn scheduler. This hook is called to notify the backend
1360 that new instructions were emitted. */
1363 "This hook is called by the insn scheduler after emitting a new instruction to\n\
1364 the instruction stream. The hook notifies a target backend to extend its\n\
1365 per instruction data structures.",
1368 /* Next 5 functions are for multi-point scheduling. */
1370 /* Allocate memory for scheduler context. */
1372 (alloc_sched_context,
1373 "Return a pointer to a store large enough to hold target scheduling context.",
1374 void *, (void), NULL)
1376 /* Fills the context from the local machine scheduler context. */
1378 (init_sched_context,
1379 "Initialize store pointed to by @var{tc} to hold target scheduling context.\n\
1380 It @var{clean_p} is true then initialize @var{tc} as if scheduler is at the\n\
1381 beginning of the block. Otherwise, copy the current context into @var{tc}.",
1382 void, (void *tc, bool clean_p), NULL)
1384 /* Sets local machine scheduler context to a saved value. */
1387 "Copy target scheduling context pointed to by @var{tc} to the current context.",
1388 void, (void *tc), NULL)
1390 /* Clears a scheduler context so it becomes like after init. */
1392 (clear_sched_context,
1393 "Deallocate internal data in target scheduling context pointed to by @var{tc}.",
1394 void, (void *tc), NULL)
1396 /* Frees the scheduler context. */
1398 (free_sched_context,
1399 "Deallocate a store for target scheduling context pointed to by @var{tc}.",
1400 void, (void *tc), NULL)
1402 /* The following member value is a pointer to a function called
1403 by the insn scheduler.
1404 The first parameter is an instruction, the second parameter is the type
1405 of the requested speculation, and the third parameter is a pointer to the
1406 speculative pattern of the corresponding type (set if return value == 1).
1408 -1, if there is no pattern, that will satisfy the requested speculation type,
1409 0, if current pattern satisfies the requested speculation type,
1410 1, if pattern of the instruction should be changed to the newly
1414 "This hook is called by the insn scheduler when @var{insn} has only\n\
1415 speculative dependencies and therefore can be scheduled speculatively.\n\
1416 The hook is used to check if the pattern of @var{insn} has a speculative\n\
1417 version and, in case of successful check, to generate that speculative\n\
1418 pattern. The hook should return 1, if the instruction has a speculative form,\n\
1419 or @minus{}1, if it doesn't. @var{request} describes the type of requested\n\
1420 speculation. If the return value equals 1 then @var{new_pat} is assigned\n\
1421 the generated speculative pattern.",
1422 int, (rtx_insn *insn, unsigned int dep_status, rtx *new_pat), NULL)
1424 /* The following member value is a pointer to a function called
1425 by the insn scheduler. It should return true if the check instruction
1426 passed as the parameter needs a recovery block. */
1429 "This hook is called by the insn scheduler during generation of recovery code\n\
1430 for @var{insn}. It should return @code{true}, if the corresponding check\n\
1431 instruction should branch to recovery code, or @code{false} otherwise.",
1432 bool, (unsigned int dep_status), NULL)
1434 /* The following member value is a pointer to a function called
1435 by the insn scheduler. It should return a pattern for the check
1437 The first parameter is a speculative instruction, the second parameter
1438 is the label of the corresponding recovery block (or null, if it is a
1439 simple check). The third parameter is the kind of speculation that
1440 is being performed. */
1443 "This hook is called by the insn scheduler to generate a pattern for recovery\n\
1444 check instruction. If @var{mutate_p} is zero, then @var{insn} is a\n\
1445 speculative instruction for which the check should be generated.\n\
1446 @var{label} is either a label of a basic block, where recovery code should\n\
1447 be emitted, or a null pointer, when requested check doesn't branch to\n\
1448 recovery code (a simple check). If @var{mutate_p} is nonzero, then\n\
1449 a pattern for a branchy check corresponding to a simple check denoted by\n\
1450 @var{insn} should be generated. In this case @var{label} can't be null.",
1451 rtx, (rtx_insn *insn, rtx_insn *label, unsigned int ds), NULL)
1453 /* The following member value is a pointer to a function that provides
1454 information about the speculation capabilities of the target.
1455 The parameter is a pointer to spec_info variable. */
1458 "This hook is used by the insn scheduler to find out what features should be\n\
1460 The structure *@var{spec_info} should be filled in by the target.\n\
1461 The structure describes speculation types that can be used in the scheduler.",
1462 void, (struct spec_info_def *spec_info), NULL)
1466 "Return speculation types of instruction @var{insn}.",
1467 unsigned int, (rtx_insn *insn), NULL)
1470 (get_insn_checked_ds,
1471 "Return speculation types that are checked for instruction @var{insn}",
1472 unsigned int, (rtx_insn *insn), NULL)
1476 "Return bool if rtx scanning should just skip current layer and\
1477 advance to the inner rtxes.",
1478 bool, (const_rtx x), NULL)
1480 /* The following member value is a pointer to a function that provides
1481 information about the target resource-based lower bound which is
1482 used by the swing modulo scheduler. The parameter is a pointer
1486 "This hook is called by the swing modulo scheduler to calculate a\n\
1487 resource-based lower bound which is based on the resources available in\n\
1488 the machine and the resources required by each instruction. The target\n\
1489 backend can use @var{g} to calculate such bound. A very simple lower\n\
1490 bound will be used in case this hook is not implemented: the total number\n\
1491 of instructions divided by the issue rate.",
1492 int, (struct ddg *g), NULL)
1494 /* The following member value is a function that initializes dispatch
1495 schedling and adds instructions to dispatch window according to its
1499 "This hook is called by Haifa Scheduler. It performs the operation specified\n\
1500 in its second parameter.",
1501 void, (rtx_insn *insn, int x),
1502 hook_void_rtx_insn_int)
1504 /* The following member value is a a function that returns true is
1505 dispatch schedling is supported in hardware and condition passed
1506 as the second parameter is true. */
1509 "This hook is called by Haifa Scheduler. It returns true if dispatch scheduling\n\
1510 is supported in hardware and the condition specified in the parameter is true.",
1511 bool, (rtx_insn *insn, int x),
1512 hook_bool_rtx_insn_int_false)
1516 "True if the processor has an exposed pipeline, which means that not just\n\
1517 the order of instructions is important for correctness when scheduling, but\n\
1518 also the latencies of operations.",
1521 /* The following member value is a function that returns number
1522 of operations reassociator should try to put in parallel for
1523 statements of the given type. By default 1 is used. */
1525 (reassociation_width,
1526 "This hook is called by tree reassociator to determine a level of\n\
1527 parallelism required in output calculations chain.",
1528 int, (unsigned int opc, machine_mode mode),
1529 hook_int_uint_mode_1)
1531 /* The following member value is a function that returns priority for
1532 fusion of each instruction via pointer parameters. */
1535 "This hook is called by scheduling fusion pass. It calculates fusion\n\
1536 priorities for each instruction passed in by parameter. The priorities\n\
1537 are returned via pointer parameters.\n\
1539 @var{insn} is the instruction whose priorities need to be calculated.\n\
1540 @var{max_pri} is the maximum priority can be returned in any cases.\n\
1541 @var{fusion_pri} is the pointer parameter through which @var{insn}'s\n\
1542 fusion priority should be calculated and returned.\n\
1543 @var{pri} is the pointer parameter through which @var{insn}'s priority\n\
1544 should be calculated and returned.\n\
1546 Same @var{fusion_pri} should be returned for instructions which should\n\
1547 be scheduled together. Different @var{pri} should be returned for\n\
1548 instructions with same @var{fusion_pri}. @var{fusion_pri} is the major\n\
1549 sort key, @var{pri} is the minor sort key. All instructions will be\n\
1550 scheduled according to the two priorities. All priorities calculated\n\
1551 should be between 0 (exclusive) and @var{max_pri} (inclusive). To avoid\n\
1552 false dependencies, @var{fusion_pri} of instructions which need to be\n\
1553 scheduled together should be smaller than @var{fusion_pri} of irrelevant\n\
1556 Given below example:\n\
1565 ldr r16, [r2, 12]\n\
1567 @end smallexample\n\
1569 On targets like ARM/AArch64, the two pairs of consecutive loads should be\n\
1570 merged. Since peephole2 pass can't help in this case unless consecutive\n\
1571 loads are actually next to each other in instruction flow. That's where\n\
1572 this scheduling fusion pass works. This hook calculates priority for each\n\
1573 instruction based on its fustion type, like:\n\
1576 ldr r10, [r1, 4] ; fusion_pri=99, pri=96\n\
1577 add r4, r4, r10 ; fusion_pri=100, pri=100\n\
1578 ldr r15, [r2, 8] ; fusion_pri=98, pri=92\n\
1579 sub r5, r5, r15 ; fusion_pri=100, pri=100\n\
1580 ldr r11, [r1, 0] ; fusion_pri=99, pri=100\n\
1581 add r4, r4, r11 ; fusion_pri=100, pri=100\n\
1582 ldr r16, [r2, 12] ; fusion_pri=98, pri=88\n\
1583 sub r5, r5, r16 ; fusion_pri=100, pri=100\n\
1584 @end smallexample\n\
1586 Scheduling fusion pass then sorts all ready to issue instructions according\n\
1587 to the priorities. As a result, instructions of same fusion type will be\n\
1588 pushed together in instruction flow, like:\n\
1594 ldr r16, [r2, 12]\n\
1599 @end smallexample\n\
1601 Now peephole2 pass can simply merge the two pairs of loads.\n\
1603 Since scheduling fusion pass relies on peephole2 to do real fusion\n\
1604 work, it is only enabled by default when peephole2 is in effect.\n\
1606 This is firstly introduced on ARM/AArch64 targets, please refer to\n\
1607 the hook implementation for how different fusion types are supported.",
1608 void, (rtx_insn *insn, int max_pri, int *fusion_pri, int *pri), NULL)
1610 HOOK_VECTOR_END (sched)
1612 /* Functions relating to OpenMP and Cilk Plus SIMD clones. */
1614 #define HOOK_PREFIX "TARGET_SIMD_CLONE_"
1615 HOOK_VECTOR (TARGET_SIMD_CLONE, simd_clone)
1618 (compute_vecsize_and_simdlen,
1619 "This hook should set @var{vecsize_mangle}, @var{vecsize_int}, @var{vecsize_float}\n\
1620 fields in @var{simd_clone} structure pointed by @var{clone_info} argument and also\n\
1621 @var{simdlen} field if it was previously 0.\n\
1622 The hook should return 0 if SIMD clones shouldn't be emitted,\n\
1623 or number of @var{vecsize_mangle} variants that should be emitted.",
1624 int, (struct cgraph_node *, struct cgraph_simd_clone *, tree, int), NULL)
1628 "This hook should add implicit @code{attribute(target(\"...\"))} attribute\n\
1629 to SIMD clone @var{node} if needed.",
1630 void, (struct cgraph_node *), NULL)
1634 "This hook should return -1 if SIMD clone @var{node} shouldn't be used\n\
1635 in vectorized loops in current function, or non-negative number if it is\n\
1636 usable. In that case, the smaller the number is, the more desirable it is\n\
1638 int, (struct cgraph_node *), NULL)
1640 HOOK_VECTOR_END (simd_clone)
1642 /* Functions relating to vectorization. */
1644 #define HOOK_PREFIX "TARGET_VECTORIZE_"
1645 HOOK_VECTOR (TARGET_VECTORIZE, vectorize)
1647 /* The following member value is a pointer to a function called
1648 by the vectorizer, and return the decl of the target builtin
1651 (builtin_mask_for_load,
1652 "This hook should return the DECL of a function @var{f} that given an\n\
1653 address @var{addr} as an argument returns a mask @var{m} that can be\n\
1654 used to extract from two vectors the relevant data that resides in\n\
1655 @var{addr} in case @var{addr} is not properly aligned.\n\
1657 The autovectorizer, when vectorizing a load operation from an address\n\
1658 @var{addr} that may be unaligned, will generate two vector loads from\n\
1659 the two aligned addresses around @var{addr}. It then generates a\n\
1660 @code{REALIGN_LOAD} operation to extract the relevant data from the\n\
1661 two loaded vectors. The first two arguments to @code{REALIGN_LOAD},\n\
1662 @var{v1} and @var{v2}, are the two vectors, each of size @var{VS}, and\n\
1663 the third argument, @var{OFF}, defines how the data will be extracted\n\
1664 from these two vectors: if @var{OFF} is 0, then the returned vector is\n\
1665 @var{v2}; otherwise, the returned vector is composed from the last\n\
1666 @var{VS}-@var{OFF} elements of @var{v1} concatenated to the first\n\
1667 @var{OFF} elements of @var{v2}.\n\
1669 If this hook is defined, the autovectorizer will generate a call\n\
1670 to @var{f} (using the DECL tree that this hook returns) and will\n\
1671 use the return value of @var{f} as the argument @var{OFF} to\n\
1672 @code{REALIGN_LOAD}. Therefore, the mask @var{m} returned by @var{f}\n\
1673 should comply with the semantics expected by @code{REALIGN_LOAD}\n\
1675 If this hook is not defined, then @var{addr} will be used as\n\
1676 the argument @var{OFF} to @code{REALIGN_LOAD}, in which case the low\n\
1677 log2(@var{VS}) @minus{} 1 bits of @var{addr} will be considered.",
1680 /* Returns a code for builtin that realizes vectorized version of
1681 function, or NULL_TREE if not available. */
1683 (builtin_vectorized_function,
1684 "This hook should return the decl of a function that implements the\n\
1685 vectorized variant of the builtin function with builtin function code\n\
1686 @var{code} or @code{NULL_TREE} if such a function is not available.\n\
1687 The value of @var{fndecl} is the builtin function declaration. The\n\
1688 return type of the vectorized function shall be of vector type\n\
1689 @var{vec_type_out} and the argument types should be @var{vec_type_in}.",
1690 tree, (tree fndecl, tree vec_type_out, tree vec_type_in),
1691 default_builtin_vectorized_function)
1693 /* Returns a function declaration for a builtin that realizes the
1694 vector conversion, or NULL_TREE if not available. */
1696 (builtin_conversion,
1697 "This hook should return the DECL of a function that implements conversion of the\n\
1698 input vector of type @var{src_type} to type @var{dest_type}.\n\
1699 The value of @var{code} is one of the enumerators in @code{enum tree_code} and\n\
1700 specifies how the conversion is to be applied\n\
1701 (truncation, rounding, etc.).\n\
1703 If this hook is defined, the autovectorizer will use the\n\
1704 @code{TARGET_VECTORIZE_BUILTIN_CONVERSION} target hook when vectorizing\n\
1705 conversion. Otherwise, it will return @code{NULL_TREE}.",
1706 tree, (unsigned code, tree dest_type, tree src_type),
1707 default_builtin_vectorized_conversion)
1709 /* Cost of different vector/scalar statements in vectorization cost
1710 model. In case of misaligned vector loads and stores the cost depends
1711 on the data type and misalignment value. */
1713 (builtin_vectorization_cost,
1714 "Returns cost of different scalar or vector statements for vectorization cost model.\n\
1715 For vector memory operations the cost may depend on type (@var{vectype}) and\n\
1716 misalignment value (@var{misalign}).",
1717 int, (enum vect_cost_for_stmt type_of_cost, tree vectype, int misalign),
1718 default_builtin_vectorization_cost)
1720 /* Return true if vector alignment is reachable (by peeling N
1721 iterations) for the given type. */
1723 (vector_alignment_reachable,
1724 "Return true if vector alignment is reachable (by peeling N iterations) for the given type.",
1725 bool, (const_tree type, bool is_packed),
1726 default_builtin_vector_alignment_reachable)
1728 /* Return true if a vector created for vec_perm_const is valid.
1729 A NULL indicates that all constants are valid permutations. */
1732 "Return true if a vector created for @code{vec_perm_const} is valid.",
1733 bool, (machine_mode, const unsigned char *sel),
1736 /* Return true if the target supports misaligned store/load of a
1737 specific factor denoted in the third parameter. The last parameter
1738 is true if the access is defined in a packed struct. */
1740 (support_vector_misalignment,
1741 "This hook should return true if the target supports misaligned vector\n\
1742 store/load of a specific factor denoted in the @var{misalignment}\n\
1743 parameter. The vector store/load should be of machine mode @var{mode} and\n\
1744 the elements in the vectors should be of type @var{type}. @var{is_packed}\n\
1745 parameter is true if the memory access is defined in a packed struct.",
1747 (machine_mode mode, const_tree type, int misalignment, bool is_packed),
1748 default_builtin_support_vector_misalignment)
1750 /* Return the builtin decl needed to load a vector of TYPE. */
1753 "This hook should return the built-in decl needed to load a vector of the "
1754 "given type within a transaction.",
1757 default_builtin_tm_load_store)
1759 /* Return the builtin decl needed to store a vector of TYPE. */
1762 "This hook should return the built-in decl needed to store a vector of the "
1763 "given type within a transaction.",
1766 default_builtin_tm_load_store)
1768 /* Returns the preferred mode for SIMD operations for the specified
1771 (preferred_simd_mode,
1772 "This hook should return the preferred mode for vectorizing scalar\n\
1773 mode @var{mode}. The default is\n\
1774 equal to @code{word_mode}, because the vectorizer can do some\n\
1775 transformations even in absence of specialized @acronym{SIMD} hardware.",
1777 (machine_mode mode),
1778 default_preferred_simd_mode)
1780 /* Returns a mask of vector sizes to iterate over when auto-vectorizing
1781 after processing the preferred one derived from preferred_simd_mode. */
1783 (autovectorize_vector_sizes,
1784 "This hook should return a mask of sizes that should be iterated over\n\
1785 after trying to autovectorize using the vector size derived from the\n\
1786 mode returned by @code{TARGET_VECTORIZE_PREFERRED_SIMD_MODE}.\n\
1787 The default is zero which means to not iterate over other vector sizes.",
1790 default_autovectorize_vector_sizes)
1792 /* Target builtin that implements vector gather operation. */
1795 "Target builtin that implements vector gather operation. @var{mem_vectype}\n\
1796 is the vector type of the load and @var{index_type} is scalar type of\n\
1797 the index, scaled by @var{scale}.\n\
1798 The default is @code{NULL_TREE} which means to not vectorize gather\n\
1801 (const_tree mem_vectype, const_tree index_type, int scale),
1804 /* Target function to initialize the cost model for a loop or block. */
1807 "This hook should initialize target-specific data structures in preparation "
1808 "for modeling the costs of vectorizing a loop or basic block. The default "
1809 "allocates three unsigned integers for accumulating costs for the prologue, "
1810 "body, and epilogue of the loop or basic block. If @var{loop_info} is "
1811 "non-NULL, it identifies the loop being vectorized; otherwise a single block "
1812 "is being vectorized.",
1814 (struct loop *loop_info),
1817 /* Target function to record N statements of the given kind using the
1818 given vector type within the cost model data for the current loop or
1822 "This hook should update the target-specific @var{data} in response to "
1823 "adding @var{count} copies of the given @var{kind} of statement to a "
1824 "loop or basic block. The default adds the builtin vectorizer cost for "
1825 "the copies of the statement to the accumulator specified by @var{where}, "
1826 "(the prologue, body, or epilogue) and returns the amount added. The "
1827 "return value should be viewed as a tentative cost that may later be "
1830 (void *data, int count, enum vect_cost_for_stmt kind,
1831 struct _stmt_vec_info *stmt_info, int misalign,
1832 enum vect_cost_model_location where),
1833 default_add_stmt_cost)
1835 /* Target function to calculate the total cost of the current vectorized
1839 "This hook should complete calculations of the cost of vectorizing a loop "
1840 "or basic block based on @var{data}, and return the prologue, body, and "
1841 "epilogue costs as unsigned integers. The default returns the value of "
1842 "the three accumulators.",
1844 (void *data, unsigned *prologue_cost, unsigned *body_cost,
1845 unsigned *epilogue_cost),
1846 default_finish_cost)
1848 /* Function to delete target-specific cost modeling data. */
1851 "This hook should release @var{data} and any related data structures "
1852 "allocated by TARGET_VECTORIZE_INIT_COST. The default releases the "
1856 default_destroy_cost_data)
1858 HOOK_VECTOR_END (vectorize)
1861 #define HOOK_PREFIX "TARGET_"
1864 (record_offload_symbol,
1865 "Used when offloaded functions are seen in the compilation unit and no named\n\
1866 sections are available. It is called once for each symbol that must be\n\
1867 recorded in the offload function and variable table.",
1872 (absolute_biggest_alignment,
1873 "If defined, this target hook specifies the absolute biggest alignment\n\
1874 that a type or variable can have on this machine, otherwise,\n\
1875 @code{BIGGEST_ALIGNMENT} is used.",
1876 HOST_WIDE_INT, BIGGEST_ALIGNMENT)
1878 /* Allow target specific overriding of option settings after options have
1879 been changed by an attribute or pragma or when it is reset at the
1880 end of the code affected by an attribute or pragma. */
1882 (override_options_after_change,
1883 "This target function is similar to the hook @code{TARGET_OPTION_OVERRIDE}\n\
1884 but is called when the optimize level is changed via an attribute or\n\
1885 pragma or when it is reset at the end of the code affected by the\n\
1886 attribute or pragma. It is not called at the beginning of compilation\n\
1887 when @code{TARGET_OPTION_OVERRIDE} is called so if you want to perform these\n\
1888 actions then, you should have @code{TARGET_OPTION_OVERRIDE} call\n\
1889 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}.",
1895 "Used when writing out the list of options into an LTO file. It should\n\
1896 translate any relevant target-specific options (such as the ABI in use)\n\
1897 into one of the @option{-foffload} options that exist as a common interface\n\
1898 to express such options. It should return a string containing these options,\n\
1899 separated by spaces, which the caller will free.\n",
1900 char *, (void), hook_charptr_void_null)
1903 (eh_return_filter_mode,
1904 "Return machine mode for filter value.",
1905 machine_mode, (void),
1906 default_eh_return_filter_mode)
1908 /* Return machine mode for libgcc expanded cmp instructions. */
1910 (libgcc_cmp_return_mode,
1911 "This target hook should return the mode to be used for the return value\n\
1912 of compare instructions expanded to libgcc calls. If not defined\n\
1913 @code{word_mode} is returned which is the right choice for a majority of\n\
1915 machine_mode, (void),
1916 default_libgcc_cmp_return_mode)
1918 /* Return machine mode for libgcc expanded shift instructions. */
1920 (libgcc_shift_count_mode,
1921 "This target hook should return the mode to be used for the shift count operand\n\
1922 of shift instructions expanded to libgcc calls. If not defined\n\
1923 @code{word_mode} is returned which is the right choice for a majority of\n\
1925 machine_mode, (void),
1926 default_libgcc_shift_count_mode)
1928 /* Return machine mode to be used for _Unwind_Word type. */
1931 "Return machine mode to be used for @code{_Unwind_Word} type.\n\
1932 The default is to use @code{word_mode}.",
1933 machine_mode, (void),
1934 default_unwind_word_mode)
1936 /* Given two decls, merge their attributes and return the result. */
1938 (merge_decl_attributes,
1939 "Define this target hook if the merging of decl attributes needs special\n\
1940 handling. If defined, the result is a list of the combined\n\
1941 @code{DECL_ATTRIBUTES} of @var{olddecl} and @var{newdecl}.\n\
1942 @var{newdecl} is a duplicate declaration of @var{olddecl}. Examples of\n\
1943 when this is needed are when one attribute overrides another, or when an\n\
1944 attribute is nullified by a subsequent definition. This function may\n\
1945 call @code{merge_attributes} to handle machine-independent merging.\n\
1947 @findex TARGET_DLLIMPORT_DECL_ATTRIBUTES\n\
1948 If the only target-specific handling you require is @samp{dllimport}\n\
1949 for Microsoft Windows targets, you should define the macro\n\
1950 @code{TARGET_DLLIMPORT_DECL_ATTRIBUTES} to @code{1}. The compiler\n\
1951 will then define a function called\n\
1952 @code{merge_dllimport_decl_attributes} which can then be defined as\n\
1953 the expansion of @code{TARGET_MERGE_DECL_ATTRIBUTES}. You can also\n\
1954 add @code{handle_dll_attribute} in the attribute table for your port\n\
1955 to perform initial processing of the @samp{dllimport} and\n\
1956 @samp{dllexport} attributes. This is done in @file{i386/cygwin.h} and\n\
1957 @file{i386/i386.c}, for example.",
1958 tree, (tree olddecl, tree newdecl),
1959 merge_decl_attributes)
1961 /* Given two types, merge their attributes and return the result. */
1963 (merge_type_attributes,
1964 "Define this target hook if the merging of type attributes needs special\n\
1965 handling. If defined, the result is a list of the combined\n\
1966 @code{TYPE_ATTRIBUTES} of @var{type1} and @var{type2}. It is assumed\n\
1967 that @code{comptypes} has already been called and returned 1. This\n\
1968 function may call @code{merge_attributes} to handle machine-independent\n\
1970 tree, (tree type1, tree type2),
1971 merge_type_attributes)
1973 /* Table of machine attributes and functions to handle them.
1977 "If defined, this target hook points to an array of @samp{struct\n\
1978 attribute_spec} (defined in @file{tree-core.h}) specifying the machine\n\
1979 specific attributes for this target and some of the restrictions on the\n\
1980 entities to which these attributes are applied and the arguments they\n\
1982 const struct attribute_spec *, NULL)
1984 /* Return true iff attribute NAME expects a plain identifier as its first
1987 (attribute_takes_identifier_p,
1988 "If defined, this target hook is a function which returns true if the\n\
1989 machine-specific attribute named @var{name} expects an identifier\n\
1990 given as its first argument to be passed on as a plain identifier, not\n\
1991 subjected to name lookup. If this is not defined, the default is\n\
1992 false for all machine-specific attributes.",
1993 bool, (const_tree name),
1994 hook_bool_const_tree_false)
1996 /* Return zero if the attributes on TYPE1 and TYPE2 are incompatible,
1997 one if they are compatible and two if they are nearly compatible
1998 (which causes a warning to be generated). */
2000 (comp_type_attributes,
2001 "If defined, this target hook is a function which returns zero if the attributes on\n\
2002 @var{type1} and @var{type2} are incompatible, one if they are compatible,\n\
2003 and two if they are nearly compatible (which causes a warning to be\n\
2004 generated). If this is not defined, machine-specific attributes are\n\
2005 supposed always to be compatible.",
2006 int, (const_tree type1, const_tree type2),
2007 hook_int_const_tree_const_tree_1)
2009 /* Assign default attributes to the newly defined TYPE. */
2011 (set_default_type_attributes,
2012 "If defined, this target hook is a function which assigns default attributes to\n\
2013 the newly defined @var{type}.",
2017 /* Insert attributes on the newly created DECL. */
2020 "Define this target hook if you want to be able to add attributes to a decl\n\
2021 when it is being created. This is normally useful for back ends which\n\
2022 wish to implement a pragma by using the attributes which correspond to\n\
2023 the pragma's effect. The @var{node} argument is the decl which is being\n\
2024 created. The @var{attr_ptr} argument is a pointer to the attribute list\n\
2025 for this decl. The list itself should not be modified, since it may be\n\
2026 shared with other decls, but attributes may be chained on the head of\n\
2027 the list and @code{*@var{attr_ptr}} modified to point to the new\n\
2028 attributes, or a copy of the list may be made if further changes are\n\
2030 void, (tree node, tree *attr_ptr),
2031 hook_void_tree_treeptr)
2033 /* Return true if FNDECL (which has at least one machine attribute)
2034 can be inlined despite its machine attributes, false otherwise. */
2036 (function_attribute_inlinable_p,
2037 "@cindex inlining\n\
2038 This target hook returns @code{true} if it is OK to inline @var{fndecl}\n\
2039 into the current function, despite its having target-specific\n\
2040 attributes, @code{false} otherwise. By default, if a function has a\n\
2041 target specific attribute attached to it, it will not be inlined.",
2042 bool, (const_tree fndecl),
2043 hook_bool_const_tree_false)
2045 /* Return true if bitfields in RECORD_TYPE should follow the
2046 Microsoft Visual C++ bitfield layout rules. */
2048 (ms_bitfield_layout_p,
2049 "This target hook returns @code{true} if bit-fields in the given\n\
2050 @var{record_type} are to be laid out following the rules of Microsoft\n\
2051 Visual C/C++, namely: (i) a bit-field won't share the same storage\n\
2052 unit with the previous bit-field if their underlying types have\n\
2053 different sizes, and the bit-field will be aligned to the highest\n\
2054 alignment of the underlying types of itself and of the previous\n\
2055 bit-field; (ii) a zero-sized bit-field will affect the alignment of\n\
2056 the whole enclosing structure, even if it is unnamed; except that\n\
2057 (iii) a zero-sized bit-field will be disregarded unless it follows\n\
2058 another bit-field of nonzero size. If this hook returns @code{true},\n\
2059 other macros that control bit-field layout are ignored.\n\
2061 When a bit-field is inserted into a packed record, the whole size\n\
2062 of the underlying type is used by one or more same-size adjacent\n\
2063 bit-fields (that is, if its long:3, 32 bits is used in the record,\n\
2064 and any additional adjacent long bit-fields are packed into the same\n\
2065 chunk of 32 bits. However, if the size changes, a new field of that\n\
2066 size is allocated). In an unpacked record, this is the same as using\n\
2067 alignment, but not equivalent when packing.\n\
2069 If both MS bit-fields and @samp{__attribute__((packed))} are used,\n\
2070 the latter will take precedence. If @samp{__attribute__((packed))} is\n\
2071 used on a single field when MS bit-fields are in use, it will take\n\
2072 precedence for that field, but the alignment of the rest of the structure\n\
2073 may affect its placement.",
2074 bool, (const_tree record_type),
2075 hook_bool_const_tree_false)
2077 /* For now this is only an interface to WORDS_BIG_ENDIAN for
2078 target-independent code like the front ends, need performance testing
2079 before switching completely to the target hook. */
2084 targhook_words_big_endian)
2086 /* Likewise for FLOAT_WORDS_BIG_ENDIAN. */
2088 (float_words_big_endian,
2091 targhook_float_words_big_endian)
2094 (float_exceptions_rounding_supported_p,
2095 "Returns true if the target supports IEEE 754 floating-point exceptions\
2096 and rounding modes, false otherwise. This is intended to relate to the\
2097 @code{float} and @code{double} types, but not necessarily @code{long double}.\
2098 By default, returns true if the @code{adddf3} instruction pattern is\
2099 available and false otherwise, on the assumption that hardware floating\
2100 point supports exceptions and rounding modes but software floating point\
2103 default_float_exceptions_rounding_supported_p)
2105 /* True if the target supports decimal floating point. */
2107 (decimal_float_supported_p,
2108 "Returns true if the target supports decimal floating point.",
2110 default_decimal_float_supported_p)
2112 /* True if the target supports fixed-point. */
2114 (fixed_point_supported_p,
2115 "Returns true if the target supports fixed-point arithmetic.",
2117 default_fixed_point_supported_p)
2119 /* Return true if anonymous bitfields affect structure alignment. */
2121 (align_anon_bitfield,
2122 "When @code{PCC_BITFIELD_TYPE_MATTERS} is true this hook will determine\n\
2123 whether unnamed bitfields affect the alignment of the containing\n\
2124 structure. The hook should return true if the structure should inherit\n\
2125 the alignment requirements of an unnamed bitfield's type.",
2127 hook_bool_void_false)
2129 /* Return true if volatile bitfields should use the narrowest type possible.
2130 Return false if they should use the container type. */
2132 (narrow_volatile_bitfield,
2133 "This target hook should return @code{true} if accesses to volatile bitfields\n\
2134 should use the narrowest mode possible. It should return @code{false} if\n\
2135 these accesses should use the bitfield container type.\n\
2137 The default is @code{false}.",
2139 hook_bool_void_false)
2141 /* Set up target-specific built-in functions. */
2144 "Define this hook if you have any machine-specific built-in functions\n\
2145 that need to be defined. It should be a function that performs the\n\
2148 Machine specific built-in functions can be useful to expand special machine\n\
2149 instructions that would otherwise not normally be generated because\n\
2150 they have no equivalent in the source language (for example, SIMD vector\n\
2151 instructions or prefetch instructions).\n\
2153 To create a built-in function, call the function\n\
2154 @code{lang_hooks.builtin_function}\n\
2155 which is defined by the language front end. You can use any type nodes set\n\
2156 up by @code{build_common_tree_nodes};\n\
2157 only language front ends that use those two functions will call\n\
2158 @samp{TARGET_INIT_BUILTINS}.",
2162 /* Initialize (if INITIALIZE_P is true) and return the target-specific
2163 built-in function decl for CODE.
2164 Return NULL if that is not possible. Return error_mark_node if CODE
2165 is outside of the range of valid target builtin function codes. */
2168 "Define this hook if you have any machine-specific built-in functions\n\
2169 that need to be defined. It should be a function that returns the\n\
2170 builtin function declaration for the builtin function code @var{code}.\n\
2171 If there is no such builtin and it cannot be initialized at this time\n\
2172 if @var{initialize_p} is true the function should return @code{NULL_TREE}.\n\
2173 If @var{code} is out of range the function should return\n\
2174 @code{error_mark_node}.",
2175 tree, (unsigned code, bool initialize_p), NULL)
2177 /* Expand a target-specific builtin. */
2181 Expand a call to a machine specific built-in function that was set up by\n\
2182 @samp{TARGET_INIT_BUILTINS}. @var{exp} is the expression for the\n\
2183 function call; the result should go to @var{target} if that is\n\
2184 convenient, and have mode @var{mode} if that is convenient.\n\
2185 @var{subtarget} may be used as the target for computing one of\n\
2186 @var{exp}'s operands. @var{ignore} is nonzero if the value is to be\n\
2187 ignored. This function should return the result of the call to the\n\
2188 built-in function.",
2190 (tree exp, rtx target, rtx subtarget, machine_mode mode, int ignore),
2191 default_expand_builtin)
2194 (builtin_chkp_function,
2195 "This hook allows target to redefine built-in functions used by\n\
2196 Pointer Bounds Checker for code instrumentation. Hook should return\n\
2197 fndecl of function implementing generic builtin whose code is\n\
2198 passed in @var{fcode}. Currently following built-in functions are\n\
2199 obtained using this hook:\n\
2200 @deftypefn {Built-in Function} __bounds_type __chkp_bndmk (const void *@var{lb}, size_t @var{size})\n\
2201 Function code - BUILT_IN_CHKP_BNDMK. This built-in function is used\n\
2202 by Pointer Bounds Checker to create bound values. @var{lb} holds low\n\
2203 bound of the resulting bounds. @var{size} holds size of created bounds.\n\
2206 @deftypefn {Built-in Function} void __chkp_bndstx (const void *@var{ptr}, __bounds_type @var{b}, const void **@var{loc})\n\
2207 Function code - @code{BUILT_IN_CHKP_BNDSTX}. This built-in function is used\n\
2208 by Pointer Bounds Checker to store bounds @var{b} for pointer @var{ptr}\n\
2209 when @var{ptr} is stored by address @var{loc}.\n\
2212 @deftypefn {Built-in Function} __bounds_type __chkp_bndldx (const void **@var{loc}, const void *@var{ptr})\n\
2213 Function code - @code{BUILT_IN_CHKP_BNDLDX}. This built-in function is used\n\
2214 by Pointer Bounds Checker to get bounds of pointer @var{ptr} loaded by\n\
2215 address @var{loc}.\n\
2218 @deftypefn {Built-in Function} void __chkp_bndcl (const void *@var{ptr}, __bounds_type @var{b})\n\
2219 Function code - @code{BUILT_IN_CHKP_BNDCL}. This built-in function is used\n\
2220 by Pointer Bounds Checker to perform check for pointer @var{ptr} against\n\
2221 lower bound of bounds @var{b}.\n\
2224 @deftypefn {Built-in Function} void __chkp_bndcu (const void *@var{ptr}, __bounds_type @var{b})\n\
2225 Function code - @code{BUILT_IN_CHKP_BNDCU}. This built-in function is used\n\
2226 by Pointer Bounds Checker to perform check for pointer @var{ptr} against\n\
2227 upper bound of bounds @var{b}.\n\
2230 @deftypefn {Built-in Function} __bounds_type __chkp_bndret (void *@var{ptr})\n\
2231 Function code - @code{BUILT_IN_CHKP_BNDRET}. This built-in function is used\n\
2232 by Pointer Bounds Checker to obtain bounds returned by a call statement.\n\
2233 @var{ptr} passed to built-in is @code{SSA_NAME} returned by the call.\n\
2236 @deftypefn {Built-in Function} __bounds_type __chkp_intersect (__bounds_type @var{b1}, __bounds_type @var{b2})\n\
2237 Function code - @code{BUILT_IN_CHKP_INTERSECT}. This built-in function\n\
2238 returns intersection of bounds @var{b1} and @var{b2}.\n\
2241 @deftypefn {Built-in Function} __bounds_type __chkp_narrow (const void *@var{ptr}, __bounds_type @var{b}, size_t @var{s})\n\
2242 Function code - @code{BUILT_IN_CHKP_NARROW}. This built-in function\n\
2243 returns intersection of bounds @var{b} and\n\
2244 [@var{ptr}, @var{ptr} + @var{s} - @code{1}].\n\
2247 @deftypefn {Built-in Function} size_t __chkp_sizeof (const void *@var{ptr})\n\
2248 Function code - @code{BUILT_IN_CHKP_SIZEOF}. This built-in function\n\
2249 returns size of object referenced by @var{ptr}. @var{ptr} is always\n\
2250 @code{ADDR_EXPR} of @code{VAR_DECL}. This built-in is used by\n\
2251 Pointer Bounds Checker when bounds of object cannot be computed statically\n\
2252 (e.g. object has incomplete type).\n\
2255 @deftypefn {Built-in Function} const void *__chkp_extract_lower (__bounds_type @var{b})\n\
2256 Function code - @code{BUILT_IN_CHKP_EXTRACT_LOWER}. This built-in function\n\
2257 returns lower bound of bounds @var{b}.\n\
2260 @deftypefn {Built-in Function} const void *__chkp_extract_upper (__bounds_type @var{b})\n\
2261 Function code - @code{BUILT_IN_CHKP_EXTRACT_UPPER}. This built-in function\n\
2262 returns upper bound of bounds @var{b}.\n\
2264 tree, (unsigned fcode),
2265 default_builtin_chkp_function)
2269 "Return type to be used for bounds",
2271 default_chkp_bound_type)
2275 "Return mode to be used for bounds.",
2276 enum machine_mode, (void),
2277 default_chkp_bound_mode)
2280 (chkp_make_bounds_constant,
2281 "Return constant used to statically initialize constant bounds\n\
2282 with specified lower bound @var{lb} and upper bounds @var{ub}.",
2283 tree, (HOST_WIDE_INT lb, HOST_WIDE_INT ub),
2284 default_chkp_make_bounds_constant)
2287 (chkp_initialize_bounds,
2288 "Generate a list of statements @var{stmts} to initialize pointer\n\
2289 bounds variable @var{var} with bounds @var{lb} and @var{ub}. Return\n\
2290 the number of generated statements.",
2291 int, (tree var, tree lb, tree ub, tree *stmts),
2292 default_chkp_initialize_bounds)
2294 /* Select a replacement for a target-specific builtin. This is done
2295 *before* regular type checking, and so allows the target to
2296 implement a crude form of function overloading. The result is a
2297 complete expression that implements the operation. PARAMS really
2298 has type VEC(tree,gc)*, but we don't want to include tree.h here. */
2300 (resolve_overloaded_builtin,
2301 "Select a replacement for a machine specific built-in function that\n\
2302 was set up by @samp{TARGET_INIT_BUILTINS}. This is done\n\
2303 @emph{before} regular type checking, and so allows the target to\n\
2304 implement a crude form of function overloading. @var{fndecl} is the\n\
2305 declaration of the built-in function. @var{arglist} is the list of\n\
2306 arguments passed to the built-in function. The result is a\n\
2307 complete expression that implements the operation, usually\n\
2308 another @code{CALL_EXPR}.\n\
2309 @var{arglist} really has type @samp{VEC(tree,gc)*}",
2310 tree, (unsigned int /*location_t*/ loc, tree fndecl, void *arglist), NULL)
2312 /* Fold a target-specific builtin to a tree valid for both GIMPLE
2316 "Fold a call to a machine specific built-in function that was set up by\n\
2317 @samp{TARGET_INIT_BUILTINS}. @var{fndecl} is the declaration of the\n\
2318 built-in function. @var{n_args} is the number of arguments passed to\n\
2319 the function; the arguments themselves are pointed to by @var{argp}.\n\
2320 The result is another tree, valid for both GIMPLE and GENERIC,\n\
2321 containing a simplified expression for the call's result. If\n\
2322 @var{ignore} is true the value will be ignored.",
2323 tree, (tree fndecl, int n_args, tree *argp, bool ignore),
2324 hook_tree_tree_int_treep_bool_null)
2326 /* Fold a target-specific builtin to a valid GIMPLE tree. */
2328 (gimple_fold_builtin,
2329 "Fold a call to a machine specific built-in function that was set up\n\
2330 by @samp{TARGET_INIT_BUILTINS}. @var{gsi} points to the gimple\n\
2331 statement holding the function call. Returns true if any change\n\
2332 was made to the GIMPLE stream.",
2333 bool, (gimple_stmt_iterator *gsi),
2334 hook_bool_gsiptr_false)
2336 /* Target hook is used to compare the target attributes in two functions to
2337 determine which function's features get higher priority. This is used
2338 during function multi-versioning to figure out the order in which two
2339 versions must be dispatched. A function version with a higher priority
2340 is checked for dispatching earlier. DECL1 and DECL2 are
2341 the two function decls that will be compared. It returns positive value
2342 if DECL1 is higher priority, negative value if DECL2 is higher priority
2343 and 0 if they are the same. */
2345 (compare_version_priority,
2346 "This hook is used to compare the target attributes in two functions to\n\
2347 determine which function's features get higher priority. This is used\n\
2348 during function multi-versioning to figure out the order in which two\n\
2349 versions must be dispatched. A function version with a higher priority\n\
2350 is checked for dispatching earlier. @var{decl1} and @var{decl2} are\n\
2351 the two function decls that will be compared.",
2352 int, (tree decl1, tree decl2), NULL)
2354 /* Target hook is used to generate the dispatcher logic to invoke the right
2355 function version at run-time for a given set of function versions.
2356 ARG points to the callgraph node of the dispatcher function whose body
2357 must be generated. */
2359 (generate_version_dispatcher_body,
2360 "This hook is used to generate the dispatcher logic to invoke the right\n\
2361 function version at run-time for a given set of function versions.\n\
2362 @var{arg} points to the callgraph node of the dispatcher function whose\n\
2363 body must be generated.",
2364 tree, (void *arg), NULL)
2366 /* Target hook is used to get the dispatcher function for a set of function
2367 versions. The dispatcher function is called to invoke the right function
2368 version at run-time. DECL is one version from a set of semantically
2369 identical versions. */
2371 (get_function_versions_dispatcher,
2372 "This hook is used to get the dispatcher function for a set of function\n\
2373 versions. The dispatcher function is called to invoke the right function\n\
2374 version at run-time. @var{decl} is one version from a set of semantically\n\
2375 identical versions.",
2376 tree, (void *decl), NULL)
2378 /* Returns a code for a target-specific builtin that implements
2379 reciprocal of the function, or NULL_TREE if not available. */
2381 (builtin_reciprocal,
2382 "This hook should return the DECL of a function that implements reciprocal of\n\
2383 the builtin function with builtin function code @var{fn}, or\n\
2384 @code{NULL_TREE} if such a function is not available. @var{md_fn} is true\n\
2385 when @var{fn} is a code of a machine-dependent builtin function. When\n\
2386 @var{sqrt} is true, additional optimizations that apply only to the reciprocal\n\
2387 of a square root function are performed, and only reciprocals of @code{sqrt}\n\
2388 function are valid.",
2389 tree, (unsigned fn, bool md_fn, bool sqrt),
2390 default_builtin_reciprocal)
2392 /* For a vendor-specific TYPE, return a pointer to a statically-allocated
2393 string containing the C++ mangling for TYPE. In all other cases, return
2397 "If your target defines any fundamental types, or any types your target\n\
2398 uses should be mangled differently from the default, define this hook\n\
2399 to return the appropriate encoding for these types as part of a C++\n\
2400 mangled name. The @var{type} argument is the tree structure representing\n\
2401 the type to be mangled. The hook may be applied to trees which are\n\
2402 not target-specific fundamental types; it should return @code{NULL}\n\
2403 for all such types, as well as arguments it does not recognize. If the\n\
2404 return value is not @code{NULL}, it must point to a statically-allocated\n\
2407 Target-specific fundamental types might be new fundamental types or\n\
2408 qualified versions of ordinary fundamental types. Encode new\n\
2409 fundamental types as @samp{@w{u @var{n} @var{name}}}, where @var{name}\n\
2410 is the name used for the type in source code, and @var{n} is the\n\
2411 length of @var{name} in decimal. Encode qualified versions of\n\
2412 ordinary types as @samp{@w{U @var{n} @var{name} @var{code}}}, where\n\
2413 @var{name} is the name used for the type qualifier in source code,\n\
2414 @var{n} is the length of @var{name} as above, and @var{code} is the\n\
2415 code used to represent the unqualified version of this type. (See\n\
2416 @code{write_builtin_type} in @file{cp/mangle.c} for the list of\n\
2417 codes.) In both cases the spaces are for clarity; do not include any\n\
2418 spaces in your string.\n\
2420 This hook is applied to types prior to typedef resolution. If the mangled\n\
2421 name for a particular type depends only on that type's main variant, you\n\
2422 can perform typedef resolution yourself using @code{TYPE_MAIN_VARIANT}\n\
2425 The default version of this hook always returns @code{NULL}, which is\n\
2426 appropriate for a target that does not define any new fundamental\n\
2428 const char *, (const_tree type),
2429 hook_constcharptr_const_tree_null)
2431 /* Make any adjustments to libfunc names needed for this target. */
2434 "This hook should declare additional library routines or rename\n\
2435 existing ones, using the functions @code{set_optab_libfunc} and\n\
2436 @code{init_one_libfunc} defined in @file{optabs.c}.\n\
2437 @code{init_optabs} calls this macro after initializing all the normal\n\
2438 library routines.\n\
2440 The default is to do nothing. Most ports don't need to define this hook.",
2444 /* Add a __gnu_ prefix to library functions rather than just __. */
2446 (libfunc_gnu_prefix,
2447 "If false (the default), internal library routines start with two\n\
2448 underscores. If set to true, these routines start with @code{__gnu_}\n\
2449 instead. E.g., @code{__muldi3} changes to @code{__gnu_muldi3}. This\n\
2450 currently only affects functions defined in @file{libgcc2.c}. If this\n\
2451 is set to true, the @file{tm.h} file must also\n\
2452 @code{#define LIBGCC2_GNU_PREFIX}.",
2455 /* Given a decl, a section name, and whether the decl initializer
2456 has relocs, choose attributes for the section. */
2457 /* ??? Should be merged with SELECT_SECTION and UNIQUE_SECTION. */
2459 (section_type_flags,
2460 "Choose a set of section attributes for use by @code{TARGET_ASM_NAMED_SECTION}\n\
2461 based on a variable or function decl, a section name, and whether or not the\n\
2462 declaration's initializer may contain runtime relocations. @var{decl} may be\n\
2463 null, in which case read-write data should be assumed.\n\
2465 The default version of this function handles choosing code vs data,\n\
2466 read-only vs read-write data, and @code{flag_pic}. You should only\n\
2467 need to override this if your target has special flags that might be\n\
2468 set via @code{__attribute__}.",
2469 unsigned int, (tree decl, const char *name, int reloc),
2470 default_section_type_flags)
2474 "This hook determines whether a function from a class of functions\n\
2475 @var{fn_class} is present at the runtime.",
2476 bool, (enum function_class fn_class),
2477 default_libc_has_function)
2479 /* True if new jumps cannot be created, to replace existing ones or
2480 not, at the current point in the compilation. */
2482 (cannot_modify_jumps_p,
2483 "This target hook returns @code{true} past the point in which new jump\n\
2484 instructions could be created. On machines that require a register for\n\
2485 every jump such as the SHmedia ISA of SH5, this point would typically be\n\
2486 reload, so this target hook should be defined to a function such as:\n\
2490 cannot_modify_jumps_past_reload_p ()\n\
2492 return (reload_completed || reload_in_progress);\n\
2496 hook_bool_void_false)
2498 /* True if FOLLOWER may be modified to follow FOLLOWEE. */
2501 "FOLLOWER and FOLLOWEE are JUMP_INSN instructions;\
2502 return true if FOLLOWER may be modified to follow FOLLOWEE;\
2503 false, if it can't.\
2504 For example, on some targets, certain kinds of branches can't be made to\
2505 follow through a hot/cold partitioning.",
2506 bool, (const rtx_insn *follower, const rtx_insn *followee),
2507 hook_bool_const_rtx_insn_const_rtx_insn_true)
2509 /* Return a register class for which branch target register
2510 optimizations should be applied. */
2512 (branch_target_register_class,
2513 "This target hook returns a register class for which branch target register\n\
2514 optimizations should be applied. All registers in this class should be\n\
2515 usable interchangeably. After reload, registers in this class will be\n\
2516 re-allocated and loads will be hoisted out of loops and be subjected\n\
2517 to inter-block scheduling.",
2518 reg_class_t, (void),
2519 default_branch_target_register_class)
2521 /* Return true if branch target register optimizations should include
2522 callee-saved registers that are not already live during the current
2523 function. AFTER_PE_GEN is true if prologues and epilogues have
2524 already been generated. */
2526 (branch_target_register_callee_saved,
2527 "Branch target register optimization will by default exclude callee-saved\n\
2529 that are not already live during the current function; if this target hook\n\
2530 returns true, they will be included. The target code must than make sure\n\
2531 that all target registers in the class returned by\n\
2532 @samp{TARGET_BRANCH_TARGET_REGISTER_CLASS} that might need saving are\n\
2533 saved. @var{after_prologue_epilogue_gen} indicates if prologues and\n\
2534 epilogues have already been generated. Note, even if you only return\n\
2535 true when @var{after_prologue_epilogue_gen} is false, you still are likely\n\
2536 to have to make special provisions in @code{INITIAL_ELIMINATION_OFFSET}\n\
2537 to reserve space for caller-saved target registers.",
2538 bool, (bool after_prologue_epilogue_gen),
2539 hook_bool_bool_false)
2541 /* Return true if the target supports conditional execution. */
2543 (have_conditional_execution,
2544 "This target hook returns true if the target supports conditional execution.\n\
2545 This target hook is required only when the target has several different\n\
2546 modes and they have different conditional execution capability, such as ARM.",
2548 default_have_conditional_execution)
2552 "This function prepares to emit a comparison insn for the first compare in a\n\
2553 sequence of conditional comparisions. It returns a appropriate @code{CC}\n\
2554 for passing to @code{gen_ccmp_next} or @code{cbranch_optab}. The insns to\n\
2555 prepare the compare are saved in @var{prep_seq} and the compare insns are\n\
2556 saved in @var{gen_seq}. They will be emitted when all the compares in the\n\
2557 the conditional comparision are generated without error. @var{code} is\n\
2558 the @code{rtx_code} of the compare for @var{op0} and @var{op1}.",
2559 rtx, (rtx *prep_seq, rtx *gen_seq, int code, tree op0, tree op1),
2564 "This function prepare to emit a conditional comparison within a sequence of\n\
2565 conditional comparisons. It returns a appropriate @code{CC} for passing to\n\
2566 @code{gen_ccmp_next} or @code{cbranch_optab}. The insns to prepare the\n\
2567 compare are saved in @var{prep_seq} and the compare insns are saved in\n\
2568 @var{gen_seq}. They will be emitted when all the compares in the conditional\n\
2569 comparision are generated without error. The @var{prev} expression is the\n\
2570 result of a prior call to @code{gen_ccmp_first} or @code{gen_ccmp_next}. It\n\
2571 may return @code{NULL} if the combination of @var{prev} and this comparison is\n\
2572 not supported, otherwise the result must be appropriate for passing to\n\
2573 @code{gen_ccmp_next} or @code{cbranch_optab}. @var{code} is the\n\
2574 @code{rtx_code} of the compare for @var{op0} and @var{op1}. @var{bit_code}\n\
2575 is @code{AND} or @code{IOR}, which is the op on the two compares.",
2576 rtx, (rtx *prep_seq, rtx *gen_seq, rtx prev, int cmp_code, tree op0, tree op1, int bit_code),
2579 /* Return a new value for loop unroll size. */
2581 (loop_unroll_adjust,
2582 "This target hook returns a new value for the number of times @var{loop}\n\
2583 should be unrolled. The parameter @var{nunroll} is the number of times\n\
2584 the loop is to be unrolled. The parameter @var{loop} is a pointer to\n\
2585 the loop, which is going to be checked for unrolling. This target hook\n\
2586 is required only when the target has special constraints like maximum\n\
2587 number of memory accesses.",
2588 unsigned, (unsigned nunroll, struct loop *loop),
2591 /* True if X is a legitimate MODE-mode immediate operand. */
2593 (legitimate_constant_p,
2594 "This hook returns true if @var{x} is a legitimate constant for a\n\
2595 @var{mode}-mode immediate operand on the target machine. You can assume that\n\
2596 @var{x} satisfies @code{CONSTANT_P}, so you need not check this.\n\
2598 The default definition returns true.",
2599 bool, (machine_mode mode, rtx x),
2600 hook_bool_mode_rtx_true)
2602 /* True if the constant X cannot be placed in the constant pool. */
2604 (cannot_force_const_mem,
2605 "This hook should return true if @var{x} is of a form that cannot (or\n\
2606 should not) be spilled to the constant pool. @var{mode} is the mode\n\
2609 The default version of this hook returns false.\n\
2611 The primary reason to define this hook is to prevent reload from\n\
2612 deciding that a non-legitimate constant would be better reloaded\n\
2613 from the constant pool instead of spilling and reloading a register\n\
2614 holding the constant. This restriction is often true of addresses\n\
2615 of TLS symbols for various targets.",
2616 bool, (machine_mode mode, rtx x),
2617 hook_bool_mode_rtx_false)
2620 (cannot_copy_insn_p,
2621 "True if the insn @var{x} cannot be duplicated.",
2622 bool, (rtx_insn *), NULL)
2624 /* True if X is considered to be commutative. */
2627 "This target hook returns @code{true} if @var{x} is considered to be commutative.\n\
2628 Usually, this is just COMMUTATIVE_P (@var{x}), but the HP PA doesn't consider\n\
2629 PLUS to be commutative inside a MEM@. @var{outer_code} is the rtx code\n\
2630 of the enclosing rtl, if known, otherwise it is UNKNOWN.",
2631 bool, (const_rtx x, int outer_code),
2632 hook_bool_const_rtx_commutative_p)
2634 /* True if ADDR is an address-expression whose effect depends
2635 on the mode of the memory reference it is used in. */
2637 (mode_dependent_address_p,
2638 "This hook returns @code{true} if memory address @var{addr} in address\n\
2639 space @var{addrspace} can have\n\
2640 different meanings depending on the machine mode of the memory\n\
2641 reference it is used for or if the address is valid for some modes\n\
2644 Autoincrement and autodecrement addresses typically have mode-dependent\n\
2645 effects because the amount of the increment or decrement is the size\n\
2646 of the operand being addressed. Some machines have other mode-dependent\n\
2647 addresses. Many RISC machines have no mode-dependent addresses.\n\
2649 You may assume that @var{addr} is a valid address for the machine.\n\
2651 The default version of this hook returns @code{false}.",
2652 bool, (const_rtx addr, addr_space_t addrspace),
2653 default_mode_dependent_address_p)
2655 /* Given an invalid address X for a given machine mode, try machine-specific
2656 ways to make it legitimate. Return X or an invalid address on failure. */
2658 (legitimize_address,
2659 "This hook is given an invalid memory address @var{x} for an\n\
2660 operand of mode @var{mode} and should try to return a valid memory\n\
2663 @findex break_out_memory_refs\n\
2664 @var{x} will always be the result of a call to @code{break_out_memory_refs},\n\
2665 and @var{oldx} will be the operand that was given to that function to produce\n\
2668 The code of the hook should not alter the substructure of\n\
2669 @var{x}. If it transforms @var{x} into a more legitimate form, it\n\
2670 should return the new @var{x}.\n\
2672 It is not necessary for this hook to come up with a legitimate address,\n\
2673 with the exception of native TLS addresses (@pxref{Emulated TLS}).\n\
2674 The compiler has standard ways of doing so in all cases. In fact, if\n\
2675 the target supports only emulated TLS, it\n\
2676 is safe to omit this hook or make it return @var{x} if it cannot find\n\
2677 a valid way to legitimize the address. But often a machine-dependent\n\
2678 strategy can generate better code.",
2679 rtx, (rtx x, rtx oldx, machine_mode mode),
2680 default_legitimize_address)
2682 /* Given an address RTX, undo the effects of LEGITIMIZE_ADDRESS. */
2684 (delegitimize_address,
2685 "This hook is used to undo the possibly obfuscating effects of the\n\
2686 @code{LEGITIMIZE_ADDRESS} and @code{LEGITIMIZE_RELOAD_ADDRESS} target\n\
2687 macros. Some backend implementations of these macros wrap symbol\n\
2688 references inside an @code{UNSPEC} rtx to represent PIC or similar\n\
2689 addressing modes. This target hook allows GCC's optimizers to understand\n\
2690 the semantics of these opaque @code{UNSPEC}s by converting them back\n\
2691 into their original form.",
2693 delegitimize_mem_from_attrs)
2695 /* Given an RTX, return true if it is not ok to emit it into debug info
2698 (const_not_ok_for_debug_p,
2699 "This hook should return true if @var{x} should not be emitted into\n\
2702 hook_bool_rtx_false)
2704 /* Given an address RTX, say whether it is valid. */
2706 (legitimate_address_p,
2707 "A function that returns whether @var{x} (an RTX) is a legitimate memory\n\
2708 address on the target machine for a memory operand of mode @var{mode}.\n\
2710 Legitimate addresses are defined in two variants: a strict variant and a\n\
2711 non-strict one. The @var{strict} parameter chooses which variant is\n\
2712 desired by the caller.\n\
2714 The strict variant is used in the reload pass. It must be defined so\n\
2715 that any pseudo-register that has not been allocated a hard register is\n\
2716 considered a memory reference. This is because in contexts where some\n\
2717 kind of register is required, a pseudo-register with no hard register\n\
2718 must be rejected. For non-hard registers, the strict variant should look\n\
2719 up the @code{reg_renumber} array; it should then proceed using the hard\n\
2720 register number in the array, or treat the pseudo as a memory reference\n\
2721 if the array holds @code{-1}.\n\
2723 The non-strict variant is used in other passes. It must be defined to\n\
2724 accept all pseudo-registers in every context where some kind of\n\
2725 register is required.\n\
2727 Normally, constant addresses which are the sum of a @code{symbol_ref}\n\
2728 and an integer are stored inside a @code{const} RTX to mark them as\n\
2729 constant. Therefore, there is no need to recognize such sums\n\
2730 specifically as legitimate addresses. Normally you would simply\n\
2731 recognize any @code{const} as legitimate.\n\
2733 Usually @code{PRINT_OPERAND_ADDRESS} is not prepared to handle constant\n\
2734 sums that are not marked with @code{const}. It assumes that a naked\n\
2735 @code{plus} indicates indexing. If so, then you @emph{must} reject such\n\
2736 naked constant sums as illegitimate addresses, so that none of them will\n\
2737 be given to @code{PRINT_OPERAND_ADDRESS}.\n\
2739 @cindex @code{TARGET_ENCODE_SECTION_INFO} and address validation\n\
2740 On some machines, whether a symbolic address is legitimate depends on\n\
2741 the section that the address refers to. On these machines, define the\n\
2742 target hook @code{TARGET_ENCODE_SECTION_INFO} to store the information\n\
2743 into the @code{symbol_ref}, and then check for it here. When you see a\n\
2744 @code{const}, you will have to look inside it to find the\n\
2745 @code{symbol_ref} in order to determine the section. @xref{Assembler\n\
2748 @cindex @code{GO_IF_LEGITIMATE_ADDRESS}\n\
2749 Some ports are still using a deprecated legacy substitute for\n\
2750 this hook, the @code{GO_IF_LEGITIMATE_ADDRESS} macro. This macro\n\
2754 #define GO_IF_LEGITIMATE_ADDRESS (@var{mode}, @var{x}, @var{label})\n\
2758 and should @code{goto @var{label}} if the address @var{x} is a valid\n\
2759 address on the target machine for a memory operand of mode @var{mode}.\n\
2761 @findex REG_OK_STRICT\n\
2762 Compiler source files that want to use the strict variant of this\n\
2763 macro define the macro @code{REG_OK_STRICT}. You should use an\n\
2764 @code{#ifdef REG_OK_STRICT} conditional to define the strict variant in\n\
2765 that case and the non-strict variant otherwise.\n\
2767 Using the hook is usually simpler because it limits the number of\n\
2768 files that are recompiled when changes are made.",
2769 bool, (machine_mode mode, rtx x, bool strict),
2770 default_legitimate_address_p)
2772 /* True if the given constant can be put into an object_block. */
2774 (use_blocks_for_constant_p,
2775 "This hook should return true if pool entries for constant @var{x} can\n\
2776 be placed in an @code{object_block} structure. @var{mode} is the mode\n\
2779 The default version returns false for all constants.",
2780 bool, (machine_mode mode, const_rtx x),
2781 hook_bool_mode_const_rtx_false)
2783 /* True if the given decl can be put into an object_block. */
2785 (use_blocks_for_decl_p,
2786 "This hook should return true if pool entries for @var{decl} should\n\
2787 be placed in an @code{object_block} structure.\n\
2789 The default version returns true for all decls.",
2790 bool, (const_tree decl),
2791 hook_bool_const_tree_true)
2793 /* The minimum and maximum byte offsets for anchored addresses. */
2796 "The minimum offset that should be applied to a section anchor.\n\
2797 On most targets, it should be the smallest offset that can be\n\
2798 applied to a base register while still giving a legitimate address\n\
2799 for every mode. The default value is 0.",
2804 "Like @code{TARGET_MIN_ANCHOR_OFFSET}, but the maximum (inclusive)\n\
2805 offset that should be applied to section anchors. The default\n\
2809 /* True if section anchors can be used to access the given symbol. */
2811 (use_anchors_for_symbol_p,
2812 "Return true if GCC should attempt to use anchors to access @code{SYMBOL_REF}\n\
2813 @var{x}. You can assume @samp{SYMBOL_REF_HAS_BLOCK_INFO_P (@var{x})} and\n\
2814 @samp{!SYMBOL_REF_ANCHOR_P (@var{x})}.\n\
2816 The default version is correct for most targets, but you might need to\n\
2817 intercept this hook to handle things like target-specific attributes\n\
2818 or target-specific sections.",
2819 bool, (const_rtx x),
2820 default_use_anchors_for_symbol_p)
2822 /* True if target supports indirect functions. */
2825 "It returns true if the target supports GNU indirect functions.\n\
2826 The support includes the assembler, linker and dynamic linker.\n\
2827 The default value of this hook is based on target's libc.",
2829 default_has_ifunc_p)
2831 /* True if it is OK to do sibling call optimization for the specified
2832 call expression EXP. DECL will be the called function, or NULL if
2833 this is an indirect call. */
2835 (function_ok_for_sibcall,
2836 "True if it is OK to do sibling call optimization for the specified\n\
2837 call expression @var{exp}. @var{decl} will be the called function,\n\
2838 or @code{NULL} if this is an indirect call.\n\
2840 It is not uncommon for limitations of calling conventions to prevent\n\
2841 tail calls to functions outside the current unit of translation, or\n\
2842 during PIC compilation. The hook is used to enforce these restrictions,\n\
2843 as the @code{sibcall} md pattern can not fail, or fall over to a\n\
2844 ``normal'' call. The criteria for successful sibling call optimization\n\
2845 may vary greatly between different architectures.",
2846 bool, (tree decl, tree exp),
2847 hook_bool_tree_tree_false)
2849 /* Establish appropriate back-end context for processing the function
2850 FNDECL. The argument might be NULL to indicate processing at top
2851 level, outside of any function scope. */
2853 (set_current_function,
2854 "The compiler invokes this hook whenever it changes its current function\n\
2855 context (@code{cfun}). You can define this function if\n\
2856 the back end needs to perform any initialization or reset actions on a\n\
2857 per-function basis. For example, it may be used to implement function\n\
2858 attributes that affect register usage or code generation patterns.\n\
2859 The argument @var{decl} is the declaration for the new function context,\n\
2860 and may be null to indicate that the compiler has left a function context\n\
2861 and is returning to processing at the top level.\n\
2862 The default hook function does nothing.\n\
2864 GCC sets @code{cfun} to a dummy function context during initialization of\n\
2865 some parts of the back end. The hook function is not invoked in this\n\
2866 situation; you need not worry about the hook being invoked recursively,\n\
2867 or when the back end is in a partially-initialized state.\n\
2868 @code{cfun} might be @code{NULL} to indicate processing at top level,\n\
2869 outside of any function scope.",
2870 void, (tree decl), hook_void_tree)
2872 /* True if EXP should be placed in a "small data" section. */
2875 "Returns true if @var{exp} should be placed into a ``small data'' section.\n\
2876 The default version of this hook always returns false.",
2877 bool, (const_tree exp),
2878 hook_bool_const_tree_false)
2880 /* True if EXP names an object for which name resolution must resolve
2881 to the current executable or shared library. */
2884 "Returns true if @var{exp} names an object for which name resolution\n\
2885 rules must resolve to the current ``module'' (dynamic shared library\n\
2886 or executable image).\n\
2888 The default version of this hook implements the name resolution rules\n\
2889 for ELF, which has a looser model of global name binding than other\n\
2890 currently supported object file formats.",
2891 bool, (const_tree exp),
2892 default_binds_local_p)
2894 /* Check if profiling code is before or after prologue. */
2896 (profile_before_prologue,
2897 "It returns true if target wants profile code emitted before prologue.\n\n\
2898 The default version of this hook use the target macro\n\
2899 @code{PROFILE_BEFORE_PROLOGUE}.",
2901 default_profile_before_prologue)
2903 /* Return true if a leaf function should stay leaf even with profiling
2906 (keep_leaf_when_profiled,
2907 "This target hook returns true if the target wants the leaf flag for\
2908 the current function to stay true even if it calls mcount. This might\
2909 make sense for targets using the leaf flag only to determine whether a\
2910 stack frame needs to be generated or not and for which the call to\
2911 mcount is generated before the function prologue.",
2913 default_keep_leaf_when_profiled)
2915 /* Modify and return the identifier of a DECL's external name,
2916 originally identified by ID, as required by the target,
2917 (eg, append @nn to windows32 stdcall function names).
2918 The default is to return ID without modification. */
2920 (mangle_decl_assembler_name,
2921 "Define this hook if you need to postprocess the assembler name generated\n\
2922 by target-independent code. The @var{id} provided to this hook will be\n\
2923 the computed name (e.g., the macro @code{DECL_NAME} of the @var{decl} in C,\n\
2924 or the mangled name of the @var{decl} in C++). The return value of the\n\
2925 hook is an @code{IDENTIFIER_NODE} for the appropriate mangled name on\n\
2926 your target system. The default implementation of this hook just\n\
2927 returns the @var{id} provided.",
2928 tree, (tree decl, tree id),
2929 default_mangle_decl_assembler_name)
2931 /* Do something target-specific to record properties of the DECL into
2932 the associated SYMBOL_REF. */
2934 (encode_section_info,
2935 "Define this hook if references to a symbol or a constant must be\n\
2936 treated differently depending on something about the variable or\n\
2937 function named by the symbol (such as what section it is in).\n\
2939 The hook is executed immediately after rtl has been created for\n\
2940 @var{decl}, which may be a variable or function declaration or\n\
2941 an entry in the constant pool. In either case, @var{rtl} is the\n\
2942 rtl in question. Do @emph{not} use @code{DECL_RTL (@var{decl})}\n\
2943 in this hook; that field may not have been initialized yet.\n\
2945 In the case of a constant, it is safe to assume that the rtl is\n\
2946 a @code{mem} whose address is a @code{symbol_ref}. Most decls\n\
2947 will also have this form, but that is not guaranteed. Global\n\
2948 register variables, for instance, will have a @code{reg} for their\n\
2949 rtl. (Normally the right thing to do with such unusual rtl is\n\
2952 The @var{new_decl_p} argument will be true if this is the first time\n\
2953 that @code{TARGET_ENCODE_SECTION_INFO} has been invoked on this decl. It will\n\
2954 be false for subsequent invocations, which will happen for duplicate\n\
2955 declarations. Whether or not anything must be done for the duplicate\n\
2956 declaration depends on whether the hook examines @code{DECL_ATTRIBUTES}.\n\
2957 @var{new_decl_p} is always true when the hook is called for a constant.\n\
2959 @cindex @code{SYMBOL_REF_FLAG}, in @code{TARGET_ENCODE_SECTION_INFO}\n\
2960 The usual thing for this hook to do is to record flags in the\n\
2961 @code{symbol_ref}, using @code{SYMBOL_REF_FLAG} or @code{SYMBOL_REF_FLAGS}.\n\
2962 Historically, the name string was modified if it was necessary to\n\
2963 encode more than one bit of information, but this practice is now\n\
2964 discouraged; use @code{SYMBOL_REF_FLAGS}.\n\
2966 The default definition of this hook, @code{default_encode_section_info}\n\
2967 in @file{varasm.c}, sets a number of commonly-useful bits in\n\
2968 @code{SYMBOL_REF_FLAGS}. Check whether the default does what you need\n\
2969 before overriding it.",
2970 void, (tree decl, rtx rtl, int new_decl_p),
2971 default_encode_section_info)
2973 /* Undo the effects of encode_section_info on the symbol string. */
2975 (strip_name_encoding,
2976 "Decode @var{name} and return the real name part, sans\n\
2977 the characters that @code{TARGET_ENCODE_SECTION_INFO}\n\
2979 const char *, (const char *name),
2980 default_strip_name_encoding)
2982 /* If shift optabs for MODE are known to always truncate the shift count,
2983 return the mask that they apply. Return 0 otherwise. */
2985 (shift_truncation_mask,
2986 "This function describes how the standard shift patterns for @var{mode}\n\
2987 deal with shifts by negative amounts or by more than the width of the mode.\n\
2988 @xref{shift patterns}.\n\
2990 On many machines, the shift patterns will apply a mask @var{m} to the\n\
2991 shift count, meaning that a fixed-width shift of @var{x} by @var{y} is\n\
2992 equivalent to an arbitrary-width shift of @var{x} by @var{y & m}. If\n\
2993 this is true for mode @var{mode}, the function should return @var{m},\n\
2994 otherwise it should return 0. A return value of 0 indicates that no\n\
2995 particular behavior is guaranteed.\n\
2997 Note that, unlike @code{SHIFT_COUNT_TRUNCATED}, this function does\n\
2998 @emph{not} apply to general shift rtxes; it applies only to instructions\n\
2999 that are generated by the named shift patterns.\n\
3001 The default implementation of this function returns\n\
3002 @code{GET_MODE_BITSIZE (@var{mode}) - 1} if @code{SHIFT_COUNT_TRUNCATED}\n\
3003 and 0 otherwise. This definition is always safe, but if\n\
3004 @code{SHIFT_COUNT_TRUNCATED} is false, and some shift patterns\n\
3005 nevertheless truncate the shift count, you may get better code\n\
3007 unsigned HOST_WIDE_INT, (machine_mode mode),
3008 default_shift_truncation_mask)
3010 /* Return the number of divisions in the given MODE that should be present,
3011 so that it is profitable to turn the division into a multiplication by
3014 (min_divisions_for_recip_mul,
3015 "When @option{-ffast-math} is in effect, GCC tries to optimize\n\
3016 divisions by the same divisor, by turning them into multiplications by\n\
3017 the reciprocal. This target hook specifies the minimum number of divisions\n\
3018 that should be there for GCC to perform the optimization for a variable\n\
3019 of mode @var{mode}. The default implementation returns 3 if the machine\n\
3020 has an instruction for the division, and 2 if it does not.",
3021 unsigned int, (machine_mode mode),
3022 default_min_divisions_for_recip_mul)
3024 /* If the representation of integral MODE is such that values are
3025 always sign-extended to a wider mode MODE_REP then return
3026 SIGN_EXTEND. Return UNKNOWN otherwise. */
3027 /* Note that the return type ought to be RTX_CODE, but that's not
3028 necessarily defined at this point. */
3031 "The representation of an integral mode can be such that the values\n\
3032 are always extended to a wider integral mode. Return\n\
3033 @code{SIGN_EXTEND} if values of @var{mode} are represented in\n\
3034 sign-extended form to @var{rep_mode}. Return @code{UNKNOWN}\n\
3035 otherwise. (Currently, none of the targets use zero-extended\n\
3036 representation this way so unlike @code{LOAD_EXTEND_OP},\n\
3037 @code{TARGET_MODE_REP_EXTENDED} is expected to return either\n\
3038 @code{SIGN_EXTEND} or @code{UNKNOWN}. Also no target extends\n\
3039 @var{mode} to @var{rep_mode} so that @var{rep_mode} is not the next\n\
3040 widest integral mode and currently we take advantage of this fact.)\n\
3042 Similarly to @code{LOAD_EXTEND_OP} you may return a non-@code{UNKNOWN}\n\
3043 value even if the extension is not performed on certain hard registers\n\
3044 as long as for the @code{REGNO_REG_CLASS} of these hard registers\n\
3045 @code{CANNOT_CHANGE_MODE_CLASS} returns nonzero.\n\
3047 Note that @code{TARGET_MODE_REP_EXTENDED} and @code{LOAD_EXTEND_OP}\n\
3048 describe two related properties. If you define\n\
3049 @code{TARGET_MODE_REP_EXTENDED (mode, word_mode)} you probably also want\n\
3050 to define @code{LOAD_EXTEND_OP (mode)} to return the same type of\n\
3053 In order to enforce the representation of @code{mode},\n\
3054 @code{TRULY_NOOP_TRUNCATION} should return false when truncating to\n\
3056 int, (machine_mode mode, machine_mode rep_mode),
3057 default_mode_rep_extended)
3059 /* True if MODE is valid for a pointer in __attribute__((mode("MODE"))). */
3061 (valid_pointer_mode,
3062 "Define this to return nonzero if the port can handle pointers\n\
3063 with machine mode @var{mode}. The default version of this\n\
3064 hook returns true for both @code{ptr_mode} and @code{Pmode}.",
3065 bool, (machine_mode mode),
3066 default_valid_pointer_mode)
3068 /* Disambiguate with errno. */
3070 (ref_may_alias_errno,
3071 "Define this to return nonzero if the memory reference @var{ref}\
3072 may alias with the system C library errno location. The default\
3073 version of this hook assumes the system C library errno location\
3074 is either a declaration of type int or accessed by dereferencing\
3076 bool, (struct ao_ref *ref),
3077 default_ref_may_alias_errno)
3079 /* Support for named address spaces. */
3081 #define HOOK_PREFIX "TARGET_ADDR_SPACE_"
3082 HOOK_VECTOR (TARGET_ADDR_SPACE_HOOKS, addr_space)
3084 /* MODE to use for a pointer into another address space. */
3087 "Define this to return the machine mode to use for pointers to\n\
3088 @var{address_space} if the target supports named address spaces.\n\
3089 The default version of this hook returns @code{ptr_mode} for the\n\
3090 generic address space only.",
3091 machine_mode, (addr_space_t address_space),
3092 default_addr_space_pointer_mode)
3094 /* MODE to use for an address in another address space. */
3097 "Define this to return the machine mode to use for addresses in\n\
3098 @var{address_space} if the target supports named address spaces.\n\
3099 The default version of this hook returns @code{Pmode} for the\n\
3100 generic address space only.",
3101 machine_mode, (addr_space_t address_space),
3102 default_addr_space_address_mode)
3104 /* True if MODE is valid for a pointer in __attribute__((mode("MODE")))
3105 in another address space. */
3107 (valid_pointer_mode,
3108 "Define this to return nonzero if the port can handle pointers\n\
3109 with machine mode @var{mode} to address space @var{as}. This target\n\
3110 hook is the same as the @code{TARGET_VALID_POINTER_MODE} target hook,\n\
3111 except that it includes explicit named address space support. The default\n\
3112 version of this hook returns true for the modes returned by either the\n\
3113 @code{TARGET_ADDR_SPACE_POINTER_MODE} or @code{TARGET_ADDR_SPACE_ADDRESS_MODE}\n\
3114 target hooks for the given address space.",
3115 bool, (machine_mode mode, addr_space_t as),
3116 default_addr_space_valid_pointer_mode)
3118 /* True if an address is a valid memory address to a given named address
3119 space for a given mode. */
3121 (legitimate_address_p,
3122 "Define this to return true if @var{exp} is a valid address for mode\n\
3123 @var{mode} in the named address space @var{as}. The @var{strict}\n\
3124 parameter says whether strict addressing is in effect after reload has\n\
3125 finished. This target hook is the same as the\n\
3126 @code{TARGET_LEGITIMATE_ADDRESS_P} target hook, except that it includes\n\
3127 explicit named address space support.",
3128 bool, (machine_mode mode, rtx exp, bool strict, addr_space_t as),
3129 default_addr_space_legitimate_address_p)
3131 /* Return an updated address to convert an invalid pointer to a named
3132 address space to a valid one. If NULL_RTX is returned use machine
3133 independent methods to make the address valid. */
3135 (legitimize_address,
3136 "Define this to modify an invalid address @var{x} to be a valid address\n\
3137 with mode @var{mode} in the named address space @var{as}. This target\n\
3138 hook is the same as the @code{TARGET_LEGITIMIZE_ADDRESS} target hook,\n\
3139 except that it includes explicit named address space support.",
3140 rtx, (rtx x, rtx oldx, machine_mode mode, addr_space_t as),
3141 default_addr_space_legitimize_address)
3143 /* True if one named address space is a subset of another named address. */
3146 "Define this to return whether the @var{subset} named address space is\n\
3147 contained within the @var{superset} named address space. Pointers to\n\
3148 a named address space that is a subset of another named address space\n\
3149 will be converted automatically without a cast if used together in\n\
3150 arithmetic operations. Pointers to a superset address space can be\n\
3151 converted to pointers to a subset address space via explicit casts.",
3152 bool, (addr_space_t subset, addr_space_t superset),
3153 default_addr_space_subset_p)
3155 /* Function to convert an rtl expression from one address space to another. */
3158 "Define this to convert the pointer expression represented by the RTL\n\
3159 @var{op} with type @var{from_type} that points to a named address\n\
3160 space to a new pointer expression with type @var{to_type} that points\n\
3161 to a different named address space. When this hook it called, it is\n\
3162 guaranteed that one of the two address spaces is a subset of the other,\n\
3163 as determined by the @code{TARGET_ADDR_SPACE_SUBSET_P} target hook.",
3164 rtx, (rtx op, tree from_type, tree to_type),
3165 default_addr_space_convert)
3167 HOOK_VECTOR_END (addr_space)
3170 #define HOOK_PREFIX "TARGET_"
3172 /* True if MODE is valid for the target. By "valid", we mean able to
3173 be manipulated in non-trivial ways. In particular, this means all
3174 the arithmetic is supported. */
3176 (scalar_mode_supported_p,
3177 "Define this to return nonzero if the port is prepared to handle\n\
3178 insns involving scalar mode @var{mode}. For a scalar mode to be\n\
3179 considered supported, all the basic arithmetic and comparisons\n\
3182 The default version of this hook returns true for any mode\n\
3183 required to handle the basic C types (as defined by the port).\n\
3184 Included here are the double-word arithmetic supported by the\n\
3185 code in @file{optabs.c}.",
3186 bool, (machine_mode mode),
3187 default_scalar_mode_supported_p)
3189 /* Similarly for vector modes. "Supported" here is less strict. At
3190 least some operations are supported; need to check optabs or builtins
3191 for further details. */
3193 (vector_mode_supported_p,
3194 "Define this to return nonzero if the port is prepared to handle\n\
3195 insns involving vector mode @var{mode}. At the very least, it\n\
3196 must have move patterns for this mode.",
3197 bool, (machine_mode mode),
3198 hook_bool_mode_false)
3202 "This hook can be used to define the alignment for a vector of type\n\
3203 @var{type}, in order to comply with a platform ABI. The default is to\n\
3204 require natural alignment for vector types. The alignment returned by\n\
3205 this hook must be a power-of-two multiple of the default alignment of\n\
3206 the vector element type.",
3207 HOST_WIDE_INT, (const_tree type),
3208 default_vector_alignment)
3210 /* True if we should try to use a scalar mode to represent an array,
3211 overriding the usual MAX_FIXED_MODE limit. */
3213 (array_mode_supported_p,
3214 "Return true if GCC should try to use a scalar mode to store an array\n\
3215 of @var{nelems} elements, given that each element has mode @var{mode}.\n\
3216 Returning true here overrides the usual @code{MAX_FIXED_MODE} limit\n\
3217 and allows GCC to use any defined integer mode.\n\
3219 One use of this hook is to support vector load and store operations\n\
3220 that operate on several homogeneous vectors. For example, ARM NEON\n\
3221 has operations like:\n\
3224 int8x8x3_t vld3_s8 (const int8_t *)\n\
3225 @end smallexample\n\
3227 where the return type is defined as:\n\
3230 typedef struct int8x8x3_t\n\
3234 @end smallexample\n\
3236 If this hook allows @code{val} to have a scalar mode, then\n\
3237 @code{int8x8x3_t} can have the same mode. GCC can then store\n\
3238 @code{int8x8x3_t}s in registers rather than forcing them onto the stack.",
3239 bool, (machine_mode mode, unsigned HOST_WIDE_INT nelems),
3240 hook_bool_mode_uhwi_false)
3243 (libgcc_floating_mode_supported_p,
3244 "Define this to return nonzero if libgcc provides support for the \n\
3245 floating-point mode @var{mode}, which is known to pass \n\
3246 @code{TARGET_SCALAR_MODE_SUPPORTED_P}. The default version of this \n\
3247 hook returns true for all of @code{SFmode}, @code{DFmode}, \n\
3248 @code{XFmode} and @code{TFmode}, if such modes exist.",
3249 bool, (machine_mode mode),
3250 default_libgcc_floating_mode_supported_p)
3252 /* Compute cost of moving data from a register of class FROM to one of
3255 (register_move_cost,
3256 "This target hook should return the cost of moving data of mode @var{mode}\n\
3257 from a register in class @var{from} to one in class @var{to}. The classes\n\
3258 are expressed using the enumeration values such as @code{GENERAL_REGS}.\n\
3259 A value of 2 is the default; other values are interpreted relative to\n\
3262 It is not required that the cost always equal 2 when @var{from} is the\n\
3263 same as @var{to}; on some machines it is expensive to move between\n\
3264 registers if they are not general registers.\n\
3266 If reload sees an insn consisting of a single @code{set} between two\n\
3267 hard registers, and if @code{TARGET_REGISTER_MOVE_COST} applied to their\n\
3268 classes returns a value of 2, reload does not check to ensure that the\n\
3269 constraints of the insn are met. Setting a cost of other than 2 will\n\
3270 allow reload to verify that the constraints are met. You should do this\n\
3271 if the @samp{mov@var{m}} pattern's constraints do not allow such copying.\n\
3273 The default version of this function returns 2.",
3274 int, (machine_mode mode, reg_class_t from, reg_class_t to),
3275 default_register_move_cost)
3277 /* Compute cost of moving registers to/from memory. */
3278 /* ??? Documenting the argument types for this hook requires a GFDL
3279 license grant. Also, the documentation uses a different name for RCLASS. */
3282 "This target hook should return the cost of moving data of mode @var{mode}\n\
3283 between a register of class @var{rclass} and memory; @var{in} is @code{false}\n\
3284 if the value is to be written to memory, @code{true} if it is to be read in.\n\
3285 This cost is relative to those in @code{TARGET_REGISTER_MOVE_COST}.\n\
3286 If moving between registers and memory is more expensive than between two\n\
3287 registers, you should add this target hook to express the relative cost.\n\
3289 If you do not add this target hook, GCC uses a default cost of 4 plus\n\
3290 the cost of copying via a secondary reload register, if one is\n\
3291 needed. If your machine requires a secondary reload register to copy\n\
3292 between memory and a register of @var{rclass} but the reload mechanism is\n\
3293 more complex than copying via an intermediate, use this target hook to\n\
3294 reflect the actual cost of the move.\n\
3296 GCC defines the function @code{memory_move_secondary_cost} if\n\
3297 secondary reloads are needed. It computes the costs due to copying via\n\
3298 a secondary register. If your machine copies from memory using a\n\
3299 secondary register in the conventional way but the default base value of\n\
3300 4 is not correct for your machine, use this target hook to add some other\n\
3301 value to the result of that function. The arguments to that function\n\
3302 are the same as to this target hook.",
3303 int, (machine_mode mode, reg_class_t rclass, bool in),
3304 default_memory_move_cost)
3307 (use_by_pieces_infrastructure_p,
3308 "GCC will attempt several strategies when asked to copy between\n\
3309 two areas of memory, or to set, clear or store to memory, for example\n\
3310 when copying a @code{struct}. The @code{by_pieces} infrastructure\n\
3311 implements such memory operations as a sequence of load, store or move\n\
3312 insns. Alternate strategies are to expand the\n\
3313 @code{movmem} or @code{setmem} optabs, to emit a library call, or to emit\n\
3314 unit-by-unit, loop-based operations.\n\
3316 This target hook should return true if, for a memory operation with a\n\
3317 given @var{size} and @var{alignment}, using the @code{by_pieces}\n\
3318 infrastructure is expected to result in better code generation.\n\
3319 Both @var{size} and @var{alignment} are measured in terms of storage\n\
3322 The parameter @var{op} is one of: @code{CLEAR_BY_PIECES},\n\
3323 @code{MOVE_BY_PIECES}, @code{SET_BY_PIECES}, @code{STORE_BY_PIECES}.\n\
3324 These describe the type of memory operation under consideration.\n\
3326 The parameter @var{speed_p} is true if the code is currently being\n\
3327 optimized for speed rather than size.\n\
3329 Returning true for higher values of @var{size} can improve code generation\n\
3330 for speed if the target does not provide an implementation of the\n\
3331 @code{movmem} or @code{setmem} standard names, if the @code{movmem} or\n\
3332 @code{setmem} implementation would be more expensive than a sequence of\n\
3333 insns, or if the overhead of a library call would dominate that of\n\
3334 the body of the memory operation.\n\
3336 Returning true for higher values of @code{size} may also cause an increase\n\
3337 in code size, for example where the number of insns emitted to perform a\n\
3338 move would be greater than that of a library call.",
3339 bool, (unsigned HOST_WIDE_INT size, unsigned int alignment,
3340 enum by_pieces_operation op, bool speed_p),
3341 default_use_by_pieces_infrastructure_p)
3343 /* True for MODE if the target expects that registers in this mode will
3344 be allocated to registers in a small register class. The compiler is
3345 allowed to use registers explicitly used in the rtl as spill registers
3346 but it should prevent extending the lifetime of these registers. */
3348 (small_register_classes_for_mode_p,
3349 "Define this to return nonzero for machine modes for which the port has\n\
3350 small register classes. If this target hook returns nonzero for a given\n\
3351 @var{mode}, the compiler will try to minimize the lifetime of registers\n\
3352 in @var{mode}. The hook may be called with @code{VOIDmode} as argument.\n\
3353 In this case, the hook is expected to return nonzero if it returns nonzero\n\
3356 On some machines, it is risky to let hard registers live across arbitrary\n\
3357 insns. Typically, these machines have instructions that require values\n\
3358 to be in specific registers (like an accumulator), and reload will fail\n\
3359 if the required hard register is used for another purpose across such an\n\
3362 Passes before reload do not know which hard registers will be used\n\
3363 in an instruction, but the machine modes of the registers set or used in\n\
3364 the instruction are already known. And for some machines, register\n\
3365 classes are small for, say, integer registers but not for floating point\n\
3366 registers. For example, the AMD x86-64 architecture requires specific\n\
3367 registers for the legacy x86 integer instructions, but there are many\n\
3368 SSE registers for floating point operations. On such targets, a good\n\
3369 strategy may be to return nonzero from this hook for @code{INTEGRAL_MODE_P}\n\
3370 machine modes but zero for the SSE register classes.\n\
3372 The default version of this hook returns false for any mode. It is always\n\
3373 safe to redefine this hook to return with a nonzero value. But if you\n\
3374 unnecessarily define it, you will reduce the amount of optimizations\n\
3375 that can be performed in some cases. If you do not define this hook\n\
3376 to return a nonzero value when it is required, the compiler will run out\n\
3377 of spill registers and print a fatal error message.",
3378 bool, (machine_mode mode),
3379 hook_bool_mode_false)
3381 /* Register number for a flags register. Only needs to be defined if the
3382 target is constrainted to use post-reload comparison elimination. */
3385 "If the target has a dedicated flags register, and it needs to use the\
3386 post-reload comparison elimination pass, then this value should be set\
3388 unsigned int, INVALID_REGNUM)
3390 /* Compute a (partial) cost for rtx X. Return true if the complete
3391 cost has been computed, and false if subexpressions should be
3392 scanned. In either case, *TOTAL contains the cost result. */
3393 /* Note that CODE and OUTER_CODE ought to be RTX_CODE, but that's
3394 not necessarily defined at this point. */
3397 "This target hook describes the relative costs of RTL expressions.\n\
3399 The cost may depend on the precise form of the expression, which is\n\
3400 available for examination in @var{x}, and the fact that @var{x} appears\n\
3401 as operand @var{opno} of an expression with rtx code @var{outer_code}.\n\
3402 That is, the hook can assume that there is some rtx @var{y} such\n\
3403 that @samp{GET_CODE (@var{y}) == @var{outer_code}} and such that\n\
3404 either (a) @samp{XEXP (@var{y}, @var{opno}) == @var{x}} or\n\
3405 (b) @samp{XVEC (@var{y}, @var{opno})} contains @var{x}.\n\
3407 @var{code} is @var{x}'s expression code---redundant, since it can be\n\
3408 obtained with @code{GET_CODE (@var{x})}.\n\
3410 In implementing this hook, you can use the construct\n\
3411 @code{COSTS_N_INSNS (@var{n})} to specify a cost equal to @var{n} fast\n\
3414 On entry to the hook, @code{*@var{total}} contains a default estimate\n\
3415 for the cost of the expression. The hook should modify this value as\n\
3416 necessary. Traditionally, the default costs are @code{COSTS_N_INSNS (5)}\n\
3417 for multiplications, @code{COSTS_N_INSNS (7)} for division and modulus\n\
3418 operations, and @code{COSTS_N_INSNS (1)} for all other operations.\n\
3420 When optimizing for code size, i.e.@: when @code{speed} is\n\
3421 false, this target hook should be used to estimate the relative\n\
3422 size cost of an expression, again relative to @code{COSTS_N_INSNS}.\n\
3424 The hook returns true when all subexpressions of @var{x} have been\n\
3425 processed, and false when @code{rtx_cost} should recurse.",
3426 bool, (rtx x, int code, int outer_code, int opno, int *total, bool speed),
3427 hook_bool_rtx_int_int_int_intp_bool_false)
3429 /* Compute the cost of X, used as an address. Never called with
3430 invalid addresses. */
3433 "This hook computes the cost of an addressing mode that contains\n\
3434 @var{address}. If not defined, the cost is computed from\n\
3435 the @var{address} expression and the @code{TARGET_RTX_COST} hook.\n\
3437 For most CISC machines, the default cost is a good approximation of the\n\
3438 true cost of the addressing mode. However, on RISC machines, all\n\
3439 instructions normally have the same length and execution time. Hence\n\
3440 all addresses will have equal costs.\n\
3442 In cases where more than one form of an address is known, the form with\n\
3443 the lowest cost will be used. If multiple forms have the same, lowest,\n\
3444 cost, the one that is the most complex will be used.\n\
3446 For example, suppose an address that is equal to the sum of a register\n\
3447 and a constant is used twice in the same basic block. When this macro\n\
3448 is not defined, the address will be computed in a register and memory\n\
3449 references will be indirect through that register. On machines where\n\
3450 the cost of the addressing mode containing the sum is no higher than\n\
3451 that of a simple indirect reference, this will produce an additional\n\
3452 instruction and possibly require an additional register. Proper\n\
3453 specification of this macro eliminates this overhead for such machines.\n\
3455 This hook is never called with an invalid address.\n\
3457 On machines where an address involving more than one register is as\n\
3458 cheap as an address computation involving only one register, defining\n\
3459 @code{TARGET_ADDRESS_COST} to reflect this can cause two registers to\n\
3460 be live over a region of code where only one would have been if\n\
3461 @code{TARGET_ADDRESS_COST} were not defined in that manner. This effect\n\
3462 should be considered in the definition of this macro. Equivalent costs\n\
3463 should probably only be given to addresses with different numbers of\n\
3464 registers on machines with lots of registers.",
3465 int, (rtx address, machine_mode mode, addr_space_t as, bool speed),
3466 default_address_cost)
3468 /* Return where to allocate pseudo for a given hard register initial value. */
3470 (allocate_initial_value,
3472 When the initial value of a hard register has been copied in a pseudo\n\
3473 register, it is often not necessary to actually allocate another register\n\
3474 to this pseudo register, because the original hard register or a stack slot\n\
3475 it has been saved into can be used. @code{TARGET_ALLOCATE_INITIAL_VALUE}\n\
3476 is called at the start of register allocation once for each hard register\n\
3477 that had its initial value copied by using\n\
3478 @code{get_func_hard_reg_initial_val} or @code{get_hard_reg_initial_val}.\n\
3479 Possible values are @code{NULL_RTX}, if you don't want\n\
3480 to do any special allocation, a @code{REG} rtx---that would typically be\n\
3481 the hard register itself, if it is known not to be clobbered---or a\n\
3483 If you are returning a @code{MEM}, this is only a hint for the allocator;\n\
3484 it might decide to use another register anyways.\n\
3485 You may use @code{current_function_is_leaf} or \n\
3486 @code{REG_N_SETS} in the hook to determine if the hard\n\
3487 register in question will not be clobbered.\n\
3488 The default value of this hook is @code{NULL}, which disables any special\n\
3490 rtx, (rtx hard_reg), NULL)
3492 /* Return nonzero if evaluating UNSPEC X might cause a trap.
3493 FLAGS has the same meaning as in rtlanal.c: may_trap_p_1. */
3496 "This target hook returns nonzero if @var{x}, an @code{unspec} or\n\
3497 @code{unspec_volatile} operation, might cause a trap. Targets can use\n\
3498 this hook to enhance precision of analysis for @code{unspec} and\n\
3499 @code{unspec_volatile} operations. You may call @code{may_trap_p_1}\n\
3500 to analyze inner elements of @var{x} in which case @var{flags} should be\n\
3502 int, (const_rtx x, unsigned flags),
3503 default_unspec_may_trap_p)
3505 /* Given a register, this hook should return a parallel of registers
3506 to represent where to find the register pieces. Define this hook
3507 if the register and its mode are represented in Dwarf in
3508 non-contiguous locations, or if the register should be
3509 represented in more than one register in Dwarf. Otherwise, this
3510 hook should return NULL_RTX. */
3512 (dwarf_register_span,
3513 "Given a register, this hook should return a parallel of registers to\n\
3514 represent where to find the register pieces. Define this hook if the\n\
3515 register and its mode are represented in Dwarf in non-contiguous\n\
3516 locations, or if the register should be represented in more than one\n\
3517 register in Dwarf. Otherwise, this hook should return @code{NULL_RTX}.\n\
3518 If not defined, the default is to return @code{NULL_RTX}.",
3522 /* Given a register return the mode of the corresponding DWARF frame
3525 (dwarf_frame_reg_mode,
3526 "Given a register, this hook should return the mode which the\n\
3527 corresponding Dwarf frame register should have. This is normally\n\
3528 used to return a smaller mode than the raw mode to prevent call\n\
3529 clobbered parts of a register altering the frame register size",
3530 machine_mode, (int regno),
3531 default_dwarf_frame_reg_mode)
3533 /* If expand_builtin_init_dwarf_reg_sizes needs to fill in table
3534 entries not corresponding directly to registers below
3535 FIRST_PSEUDO_REGISTER, this hook should generate the necessary
3536 code, given the address of the table. */
3538 (init_dwarf_reg_sizes_extra,
3539 "If some registers are represented in Dwarf-2 unwind information in\n\
3540 multiple pieces, define this hook to fill in information about the\n\
3541 sizes of those pieces in the table used by the unwinder at runtime.\n\
3542 It will be called by @code{expand_builtin_init_dwarf_reg_sizes} after\n\
3543 filling in a single size corresponding to each hard register;\n\
3544 @var{address} is the address of the table.",
3545 void, (tree address),
3548 /* Fetch the fixed register(s) which hold condition codes, for
3549 targets where it makes sense to look for duplicate assignments to
3550 the condition codes. This should return true if there is such a
3551 register, false otherwise. The arguments should be set to the
3552 fixed register numbers. Up to two condition code registers are
3553 supported. If there is only one for this target, the int pointed
3554 at by the second argument should be set to -1. */
3556 (fixed_condition_code_regs,
3557 "On targets which do not use @code{(cc0)}, and which use a hard\n\
3558 register rather than a pseudo-register to hold condition codes, the\n\
3559 regular CSE passes are often not able to identify cases in which the\n\
3560 hard register is set to a common value. Use this hook to enable a\n\
3561 small pass which optimizes such cases. This hook should return true\n\
3562 to enable this pass, and it should set the integers to which its\n\
3563 arguments point to the hard register numbers used for condition codes.\n\
3564 When there is only one such register, as is true on most systems, the\n\
3565 integer pointed to by @var{p2} should be set to\n\
3566 @code{INVALID_REGNUM}.\n\
3568 The default version of this hook returns false.",
3569 bool, (unsigned int *p1, unsigned int *p2),
3570 hook_bool_uintp_uintp_false)
3572 /* If two condition code modes are compatible, return a condition
3573 code mode which is compatible with both, such that a comparison
3574 done in the returned mode will work for both of the original
3575 modes. If the condition code modes are not compatible, return
3578 (cc_modes_compatible,
3579 "On targets which use multiple condition code modes in class\n\
3580 @code{MODE_CC}, it is sometimes the case that a comparison can be\n\
3581 validly done in more than one mode. On such a system, define this\n\
3582 target hook to take two mode arguments and to return a mode in which\n\
3583 both comparisons may be validly done. If there is no such mode,\n\
3584 return @code{VOIDmode}.\n\
3586 The default version of this hook checks whether the modes are the\n\
3587 same. If they are, it returns that mode. If they are different, it\n\
3588 returns @code{VOIDmode}.",
3589 machine_mode, (machine_mode m1, machine_mode m2),
3590 default_cc_modes_compatible)
3592 /* Do machine-dependent code transformations. Called just before
3593 delayed-branch scheduling. */
3595 (machine_dependent_reorg,
3596 "If non-null, this hook performs a target-specific pass over the\n\
3597 instruction stream. The compiler will run it at all optimization levels,\n\
3598 just before the point at which it normally does delayed-branch scheduling.\n\
3600 The exact purpose of the hook varies from target to target. Some use\n\
3601 it to do transformations that are necessary for correctness, such as\n\
3602 laying out in-function constant pools or avoiding hardware hazards.\n\
3603 Others use it as an opportunity to do some machine-dependent optimizations.\n\
3605 You need not implement the hook if it has nothing to do. The default\n\
3606 definition is null.",
3609 /* Create the __builtin_va_list type. */
3611 (build_builtin_va_list,
3612 "This hook returns a type node for @code{va_list} for the target.\n\
3613 The default version of the hook returns @code{void*}.",
3615 std_build_builtin_va_list)
3617 /* Enumerate the va list variants. */
3620 "This target hook is used in function @code{c_common_nodes_and_builtins}\n\
3621 to iterate through the target specific builtin types for va_list. The\n\
3622 variable @var{idx} is used as iterator. @var{pname} has to be a pointer\n\
3623 to a @code{const char *} and @var{ptree} a pointer to a @code{tree} typed\n\
3625 The arguments @var{pname} and @var{ptree} are used to store the result of\n\
3626 this macro and are set to the name of the va_list builtin type and its\n\
3628 If the return value of this macro is zero, then there is no more element.\n\
3629 Otherwise the @var{IDX} should be increased for the next call of this\n\
3630 macro to iterate through all types.",
3631 int, (int idx, const char **pname, tree *ptree),
3634 /* Get the cfun/fndecl calling abi __builtin_va_list type. */
3637 "This hook returns the va_list type of the calling convention specified by\n\
3639 The default version of this hook returns @code{va_list_type_node}.",
3640 tree, (tree fndecl),
3643 /* Get the __builtin_va_list type dependent on input type. */
3645 (canonical_va_list_type,
3646 "This hook returns the va_list type of the calling convention specified by the\n\
3647 type of @var{type}. If @var{type} is not a valid va_list type, it returns\n\
3650 std_canonical_va_list_type)
3652 /* ??? Documenting this hook requires a GFDL license grant. */
3654 (expand_builtin_va_start,
3655 "Expand the @code{__builtin_va_start} builtin.",
3656 void, (tree valist, rtx nextarg), NULL)
3658 /* Gimplifies a VA_ARG_EXPR. */
3660 (gimplify_va_arg_expr,
3661 "This hook performs target-specific gimplification of\n\
3662 @code{VA_ARG_EXPR}. The first two parameters correspond to the\n\
3663 arguments to @code{va_arg}; the latter two are as in\n\
3664 @code{gimplify.c:gimplify_expr}.",
3665 tree, (tree valist, tree type, gimple_seq *pre_p, gimple_seq *post_p),
3666 std_gimplify_va_arg_expr)
3668 /* Validity-checking routines for PCH files, target-specific.
3669 get_pch_validity returns a pointer to the data to be stored,
3670 and stores the size in its argument. pch_valid_p gets the same
3671 information back and returns NULL if the PCH is valid,
3672 or an error message if not. */
3675 "This hook returns a pointer to the data needed by\n\
3676 @code{TARGET_PCH_VALID_P} and sets\n\
3677 @samp{*@var{sz}} to the size of the data in bytes.",
3678 void *, (size_t *sz),
3679 default_get_pch_validity)
3683 "This hook checks whether the options used to create a PCH file are\n\
3684 compatible with the current settings. It returns @code{NULL}\n\
3685 if so and a suitable error message if not. Error messages will\n\
3686 be presented to the user and must be localized using @samp{_(@var{msg})}.\n\
3688 @var{data} is the data that was returned by @code{TARGET_GET_PCH_VALIDITY}\n\
3689 when the PCH file was created and @var{sz} is the size of that data in bytes.\n\
3690 It's safe to assume that the data was created by the same version of the\n\
3691 compiler, so no format checking is needed.\n\
3693 The default definition of @code{default_pch_valid_p} should be\n\
3694 suitable for most targets.",
3695 const char *, (const void *data, size_t sz),
3696 default_pch_valid_p)
3700 "Called before writing out a PCH file. If the target has some\n\
3701 garbage-collected data that needs to be in a particular state on PCH loads,\n\
3702 it can use this hook to enforce that state. Very few targets need\n\
3703 to do anything here.",
3707 /* If nonnull, this function checks whether a PCH file with the
3708 given set of target flags can be used. It returns NULL if so,
3709 otherwise it returns an error message. */
3711 (check_pch_target_flags,
3712 "If this hook is nonnull, the default implementation of\n\
3713 @code{TARGET_PCH_VALID_P} will use it to check for compatible values\n\
3714 of @code{target_flags}. @var{pch_flags} specifies the value that\n\
3715 @code{target_flags} had when the PCH file was created. The return\n\
3716 value is the same as for @code{TARGET_PCH_VALID_P}.",
3717 const char *, (int pch_flags), NULL)
3719 /* True if the compiler should give an enum type only as many
3720 bytes as it takes to represent the range of possible values of
3723 (default_short_enums,
3724 "This target hook should return true if the compiler should give an\n\
3725 @code{enum} type only as many bytes as it takes to represent the range\n\
3726 of possible values of that type. It should return false if all\n\
3727 @code{enum} types should be allocated like @code{int}.\n\
3729 The default is to return false.",
3731 hook_bool_void_false)
3733 /* This target hook returns an rtx that is used to store the address
3734 of the current frame into the built-in setjmp buffer. */
3736 (builtin_setjmp_frame_value,
3737 "This target hook should return an rtx that is used to store\n\
3738 the address of the current frame into the built in @code{setjmp} buffer.\n\
3739 The default value, @code{virtual_stack_vars_rtx}, is correct for most\n\
3740 machines. One reason you may need to define this target hook is if\n\
3741 @code{hard_frame_pointer_rtx} is the appropriate value on your machine.",
3743 default_builtin_setjmp_frame_value)
3745 /* This target hook should manipulate the outputs, inputs, constraints,
3746 and clobbers the port wishes for pre-processing the asm. */
3749 "This target hook may add @dfn{clobbers} to @var{clobbers} and\n\
3750 @var{clobbered_regs} for any hard regs the port wishes to automatically\n\
3751 clobber for an asm. The @var{outputs} and @var{inputs} may be inspected\n\
3752 to avoid clobbering a register that is already used by the asm.\n\
3754 It may modify the @var{outputs}, @var{inputs}, and @var{constraints}\n\
3755 as necessary for other pre-processing. In this case the return value is\n\
3756 a sequence of insns to emit after the asm.",
3758 (vec<rtx>& outputs, vec<rtx>& inputs, vec<const char *>& constraints,
3759 vec<rtx>& clobbers, HARD_REG_SET& clobbered_regs),
3762 /* This target hook allows the backend to specify a calling convention
3763 in the debug information. This function actually returns an
3764 enum dwarf_calling_convention, but because of forward declarations
3765 and not wanting to include dwarf2.h everywhere target.h is included
3766 the function is being declared as an int. */
3768 (dwarf_calling_convention,
3769 "Define this to enable the dwarf attribute @code{DW_AT_calling_convention} to\n\
3770 be emitted for each function. Instead of an integer return the enum\n\
3771 value for the @code{DW_CC_} tag.",
3772 int, (const_tree function),
3773 hook_int_const_tree_0)
3775 /* This target hook allows the backend to emit frame-related insns that
3776 contain UNSPECs or UNSPEC_VOLATILEs. The call frame debugging info
3777 engine will invoke it on insns of the form
3778 (set (reg) (unspec [...] UNSPEC_INDEX))
3780 (set (reg) (unspec_volatile [...] UNSPECV_INDEX))
3781 to let the backend emit the call frame instructions. */
3783 (dwarf_handle_frame_unspec,
3784 "This target hook allows the backend to emit frame-related insns that\n\
3785 contain UNSPECs or UNSPEC_VOLATILEs. The DWARF 2 call frame debugging\n\
3786 info engine will invoke it on insns of the form\n\
3788 (set (reg) (unspec [@dots{}] UNSPEC_INDEX))\n\
3789 @end smallexample\n\
3792 (set (reg) (unspec_volatile [@dots{}] UNSPECV_INDEX)).\n\
3793 @end smallexample\n\
3794 to let the backend emit the call frame instructions. @var{label} is\n\
3795 the CFI label attached to the insn, @var{pattern} is the pattern of\n\
3796 the insn and @var{index} is @code{UNSPEC_INDEX} or @code{UNSPECV_INDEX}.",
3797 void, (const char *label, rtx pattern, int index), NULL)
3799 /* ??? Documenting this hook requires a GFDL license grant. */
3801 (stdarg_optimize_hook,
3802 "Perform architecture specific checking of statements gimplified\
3803 from @code{VA_ARG_EXPR}. @var{stmt} is the statement. Returns true if\
3804 the statement doesn't need to be checked for @code{va_list} references.",
3805 bool, (struct stdarg_info *ai, const_gimple stmt), NULL)
3807 /* This target hook allows the operating system to override the DECL
3808 that represents the external variable that contains the stack
3809 protection guard variable. The type of this DECL is ptr_type_node. */
3811 (stack_protect_guard,
3812 "This hook returns a @code{DECL} node for the external variable to use\n\
3813 for the stack protection guard. This variable is initialized by the\n\
3814 runtime to some random value and is used to initialize the guard value\n\
3815 that is placed at the top of the local stack frame. The type of this\n\
3816 variable must be @code{ptr_type_node}.\n\
3818 The default version of this hook creates a variable called\n\
3819 @samp{__stack_chk_guard}, which is normally defined in @file{libgcc2.c}.",
3821 default_stack_protect_guard)
3823 /* This target hook allows the operating system to override the CALL_EXPR
3824 that is invoked when a check vs the guard variable fails. */
3826 (stack_protect_fail,
3827 "This hook returns a @code{CALL_EXPR} that alerts the runtime that the\n\
3828 stack protect guard variable has been modified. This expression should\n\
3829 involve a call to a @code{noreturn} function.\n\
3831 The default version of this hook invokes a function called\n\
3832 @samp{__stack_chk_fail}, taking no arguments. This function is\n\
3833 normally defined in @file{libgcc2.c}.",
3835 default_external_stack_protect_fail)
3839 "Return true if it is possible to use low-overhead loops (@code{doloop_end}\n\
3840 and @code{doloop_begin}) for a particular loop. @var{iterations} gives the\n\
3841 exact number of iterations, or 0 if not known. @var{iterations_max} gives\n\
3842 the maximum number of iterations, or 0 if not known. @var{loop_depth} is\n\
3843 the nesting depth of the loop, with 1 for innermost loops, 2 for loops that\n\
3844 contain innermost loops, and so on. @var{entered_at_top} is true if the\n\
3845 loop is only entered from the top.\n\
3847 This hook is only used if @code{doloop_end} is available. The default\n\
3848 implementation returns true. You can use @code{can_use_doloop_if_innermost}\n\
3849 if the loop must be the innermost, and if there are no other restrictions.",
3850 bool, (const widest_int &iterations, const widest_int &iterations_max,
3851 unsigned int loop_depth, bool entered_at_top),
3852 hook_bool_wint_wint_uint_bool_true)
3854 /* Returns NULL if target supports the insn within a doloop block,
3855 otherwise it returns an error message. */
3857 (invalid_within_doloop,
3859 Take an instruction in @var{insn} and return NULL if it is valid within a\n\
3860 low-overhead loop, otherwise return a string explaining why doloop\n\
3861 could not be applied.\n\
3863 Many targets use special registers for low-overhead looping. For any\n\
3864 instruction that clobbers these this function should return a string indicating\n\
3865 the reason why the doloop could not be applied.\n\
3866 By default, the RTL loop optimizer does not use a present doloop pattern for\n\
3867 loops containing function calls or branch on table instructions.",
3868 const char *, (const rtx_insn *insn),
3869 default_invalid_within_doloop)
3871 /* Returns true for a legitimate combined insn. */
3873 (legitimate_combined_insn,
3874 "Take an instruction in @var{insn} and return @code{false} if the instruction\
3875 is not appropriate as a combination of two or more instructions. The\
3876 default is to accept all instructions.",
3877 bool, (rtx_insn *insn),
3878 hook_bool_rtx_insn_true)
3881 (valid_dllimport_attribute_p,
3882 "@var{decl} is a variable or function with @code{__attribute__((dllimport))}\
3883 specified. Use this hook if the target needs to add extra validation\
3884 checks to @code{handle_dll_attribute}.",
3885 bool, (const_tree decl),
3886 hook_bool_const_tree_true)
3888 /* If non-zero, align constant anchors in CSE to a multiple of this
3892 "On some architectures it can take multiple instructions to synthesize\n\
3893 a constant. If there is another constant already in a register that\n\
3894 is close enough in value then it is preferable that the new constant\n\
3895 is computed from this register using immediate addition or\n\
3896 subtraction. We accomplish this through CSE. Besides the value of\n\
3897 the constant we also add a lower and an upper constant anchor to the\n\
3898 available expressions. These are then queried when encountering new\n\
3899 constants. The anchors are computed by rounding the constant up and\n\
3900 down to a multiple of the value of @code{TARGET_CONST_ANCHOR}.\n\
3901 @code{TARGET_CONST_ANCHOR} should be the maximum positive value\n\
3902 accepted by immediate-add plus one. We currently assume that the\n\
3903 value of @code{TARGET_CONST_ANCHOR} is a power of 2. For example, on\n\
3904 MIPS, where add-immediate takes a 16-bit signed value,\n\
3905 @code{TARGET_CONST_ANCHOR} is set to @samp{0x8000}. The default value\n\
3906 is zero, which disables this optimization.",
3907 unsigned HOST_WIDE_INT, 0)
3909 /* Defines, which target-dependent bits (upper 16) are used by port */
3912 "Validate target specific memory model mask bits. When NULL no target specific\n\
3913 memory model bits are allowed.",
3914 unsigned HOST_WIDE_INT, (unsigned HOST_WIDE_INT val), NULL)
3916 /* Defines an offset bitwise ored into shifted address to get corresponding
3917 Address Sanitizer shadow address, or -1 if Address Sanitizer is not
3918 supported by the target. */
3920 (asan_shadow_offset,
3921 "Return the offset bitwise ored into shifted address to get corresponding\n\
3922 Address Sanitizer shadow memory address. NULL if Address Sanitizer is not\n\
3923 supported by the target.",
3924 unsigned HOST_WIDE_INT, (void),
3927 /* Functions relating to calls - argument passing, returns, etc. */
3928 /* Members of struct call have no special macro prefix. */
3929 HOOK_VECTOR (TARGET_CALLS, calls)
3932 (promote_function_mode,
3933 "Like @code{PROMOTE_MODE}, but it is applied to outgoing function arguments or\n\
3934 function return values. The target hook should return the new mode\n\
3935 and possibly change @code{*@var{punsignedp}} if the promotion should\n\
3936 change signedness. This function is called only for scalar @emph{or\n\
3939 @var{for_return} allows to distinguish the promotion of arguments and\n\
3940 return values. If it is @code{1}, a return value is being promoted and\n\
3941 @code{TARGET_FUNCTION_VALUE} must perform the same promotions done here.\n\
3942 If it is @code{2}, the returned mode should be that of the register in\n\
3943 which an incoming parameter is copied, or the outgoing result is computed;\n\
3944 then the hook should return the same mode as @code{promote_mode}, though\n\
3945 the signedness may be different.\n\
3947 @var{type} can be NULL when promoting function arguments of libcalls.\n\
3949 The default is to not promote arguments and return values. You can\n\
3950 also define the hook to @code{default_promote_function_mode_always_promote}\n\
3951 if you would like to apply the same rules given by @code{PROMOTE_MODE}.",
3952 machine_mode, (const_tree type, machine_mode mode, int *punsignedp,
3953 const_tree funtype, int for_return),
3954 default_promote_function_mode)
3957 (promote_prototypes,
3958 "This target hook returns @code{true} if an argument declared in a\n\
3959 prototype as an integral type smaller than @code{int} should actually be\n\
3960 passed as an @code{int}. In addition to avoiding errors in certain\n\
3961 cases of mismatch, it also makes for better code on certain machines.\n\
3962 The default is to not promote prototypes.",
3963 bool, (const_tree fntype),
3964 hook_bool_const_tree_false)
3968 "This target hook should return the location of the structure value\n\
3969 address (normally a @code{mem} or @code{reg}), or 0 if the address is\n\
3970 passed as an ``invisible'' first argument. Note that @var{fndecl} may\n\
3971 be @code{NULL}, for libcalls. You do not need to define this target\n\
3972 hook if the address is always passed as an ``invisible'' first\n\
3975 On some architectures the place where the structure value address\n\
3976 is found by the called function is not the same place that the\n\
3977 caller put it. This can be due to register windows, or it could\n\
3978 be because the function prologue moves it to a different place.\n\
3979 @var{incoming} is @code{1} or @code{2} when the location is needed in\n\
3980 the context of the called function, and @code{0} in the context of\n\
3983 If @var{incoming} is nonzero and the address is to be found on the\n\
3984 stack, return a @code{mem} which refers to the frame pointer. If\n\
3985 @var{incoming} is @code{2}, the result is being used to fetch the\n\
3986 structure value address at the beginning of a function. If you need\n\
3987 to emit adjusting code, you should do it at this point.",
3988 rtx, (tree fndecl, int incoming),
3989 hook_rtx_tree_int_null)
3992 (omit_struct_return_reg,
3993 "Normally, when a function returns a structure by memory, the address\n\
3994 is passed as an invisible pointer argument, but the compiler also\n\
3995 arranges to return the address from the function like it would a normal\n\
3996 pointer return value. Define this to true if that behaviour is\n\
3997 undesirable on your target.",
4002 "This target hook should return a nonzero value to say to return the\n\
4003 function value in memory, just as large structures are always returned.\n\
4004 Here @var{type} will be the data type of the value, and @var{fntype}\n\
4005 will be the type of the function doing the returning, or @code{NULL} for\n\
4008 Note that values of mode @code{BLKmode} must be explicitly handled\n\
4009 by this function. Also, the option @option{-fpcc-struct-return}\n\
4010 takes effect regardless of this macro. On most systems, it is\n\
4011 possible to leave the hook undefined; this causes a default\n\
4012 definition to be used, whose value is the constant 1 for @code{BLKmode}\n\
4013 values, and 0 otherwise.\n\
4015 Do not use this hook to indicate that structures and unions should always\n\
4016 be returned in memory. You should instead use @code{DEFAULT_PCC_STRUCT_RETURN}\n\
4018 bool, (const_tree type, const_tree fntype),
4019 default_return_in_memory)
4023 "This hook should return true if values of type @var{type} are returned\n\
4024 at the most significant end of a register (in other words, if they are\n\
4025 padded at the least significant end). You can assume that @var{type}\n\
4026 is returned in a register; the caller is required to check this.\n\
4028 Note that the register provided by @code{TARGET_FUNCTION_VALUE} must\n\
4029 be able to hold the complete return value. For example, if a 1-, 2-\n\
4030 or 3-byte structure is returned at the most significant end of a\n\
4031 4-byte register, @code{TARGET_FUNCTION_VALUE} should provide an\n\
4032 @code{SImode} rtx.",
4033 bool, (const_tree type),
4034 hook_bool_const_tree_false)
4036 /* Return true if a parameter must be passed by reference. TYPE may
4037 be null if this is a libcall. CA may be null if this query is
4038 from __builtin_va_arg. */
4041 "This target hook should return @code{true} if an argument at the\n\
4042 position indicated by @var{cum} should be passed by reference. This\n\
4043 predicate is queried after target independent reasons for being\n\
4044 passed by reference, such as @code{TREE_ADDRESSABLE (type)}.\n\
4046 If the hook returns true, a copy of that argument is made in memory and a\n\
4047 pointer to the argument is passed instead of the argument itself.\n\
4048 The pointer is passed in whatever way is appropriate for passing a pointer\n\
4051 (cumulative_args_t cum, machine_mode mode, const_tree type, bool named),
4052 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
4055 (expand_builtin_saveregs,
4056 "If defined, this hook produces the machine-specific code for a call to\n\
4057 @code{__builtin_saveregs}. This code will be moved to the very\n\
4058 beginning of the function, before any parameter access are made. The\n\
4059 return value of this function should be an RTX that contains the value\n\
4060 to use as the return of @code{__builtin_saveregs}.",
4062 default_expand_builtin_saveregs)
4064 /* Returns pretend_argument_size. */
4066 (setup_incoming_varargs,
4067 "This target hook offers an alternative to using\n\
4068 @code{__builtin_saveregs} and defining the hook\n\
4069 @code{TARGET_EXPAND_BUILTIN_SAVEREGS}. Use it to store the anonymous\n\
4070 register arguments into the stack so that all the arguments appear to\n\
4071 have been passed consecutively on the stack. Once this is done, you can\n\
4072 use the standard implementation of varargs that works for machines that\n\
4073 pass all their arguments on the stack.\n\
4075 The argument @var{args_so_far} points to the @code{CUMULATIVE_ARGS} data\n\
4076 structure, containing the values that are obtained after processing the\n\
4077 named arguments. The arguments @var{mode} and @var{type} describe the\n\
4078 last named argument---its machine mode and its data type as a tree node.\n\
4080 The target hook should do two things: first, push onto the stack all the\n\
4081 argument registers @emph{not} used for the named arguments, and second,\n\
4082 store the size of the data thus pushed into the @code{int}-valued\n\
4083 variable pointed to by @var{pretend_args_size}. The value that you\n\
4084 store here will serve as additional offset for setting up the stack\n\
4087 Because you must generate code to push the anonymous arguments at\n\
4088 compile time without knowing their data types,\n\
4089 @code{TARGET_SETUP_INCOMING_VARARGS} is only useful on machines that\n\
4090 have just a single category of argument register and use it uniformly\n\
4091 for all data types.\n\
4093 If the argument @var{second_time} is nonzero, it means that the\n\
4094 arguments of the function are being analyzed for the second time. This\n\
4095 happens for an inline function, which is not actually compiled until the\n\
4096 end of the source file. The hook @code{TARGET_SETUP_INCOMING_VARARGS} should\n\
4097 not generate any instructions in this case.",
4098 void, (cumulative_args_t args_so_far, machine_mode mode, tree type,
4099 int *pretend_args_size, int second_time),
4100 default_setup_incoming_varargs)
4103 (load_bounds_for_arg,
4104 "This hook is used by expand pass to emit insn to load bounds of\n\
4105 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4106 bounds of @var{arg} are not passed in register. If @var{slot} is a\n\
4107 memory, then bounds are loaded as for regular pointer loaded from\n\
4108 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4109 constant holding number of the target dependent special slot which\n\
4110 should be used to obtain bounds. Hook returns RTX holding loaded bounds.",
4111 rtx, (rtx slot, rtx arg, rtx slot_no),
4112 default_load_bounds_for_arg)
4115 (store_bounds_for_arg,
4116 "This hook is used by expand pass to emit insns to store @var{bounds} of\n\
4117 @var{arg} passed in @var{slot}. Expand pass uses this hook in case\n\
4118 @var{bounds} of @var{arg} are not passed in register. If @var{slot} is a\n\
4119 memory, then @var{bounds} are stored as for regular pointer stored in\n\
4120 memory. If @var{slot} is not a memory then @var{slot_no} is an integer\n\
4121 constant holding number of the target dependent special slot which\n\
4122 should be used to store @var{bounds}.",
4123 void, (rtx arg, rtx slot, rtx bounds, rtx slot_no),
4124 default_store_bounds_for_arg)
4127 (load_returned_bounds,
4128 "This hook is used by expand pass to emit insn to load bounds\n\
4129 returned by function call in @var{slot}. Hook returns RTX holding\n\
4132 default_load_returned_bounds)
4135 (store_returned_bounds,
4136 "This hook is used by expand pass to emit insn to store @var{bounds}\n\
4137 returned by function call into @var{slot}.",
4138 void, (rtx slot, rtx bounds),
4139 default_store_returned_bounds)
4142 (setup_incoming_vararg_bounds,
4143 "Use it to store bounds for anonymous register arguments stored\n\
4144 into the stack. Arguments meaning is similar to\n\
4145 @code{TARGET_SETUP_INCOMING_VARARGS}.",
4146 void, (cumulative_args_t args_so_far, enum machine_mode mode, tree type,
4147 int *pretend_args_size, int second_time),
4148 default_setup_incoming_vararg_bounds)
4152 "While generating RTL for a function call, this target hook is invoked once\n\
4153 for each argument passed to the function, either a register returned by\n\
4154 @code{TARGET_FUNCTION_ARG} or a memory location. It is called just\n\
4155 before the point where argument registers are stored. The type of the\n\
4156 function to be called is also passed as the second argument; it is\n\
4157 @code{NULL_TREE} for libcalls. The @code{TARGET_END_CALL_ARGS} hook is\n\
4158 invoked just after the code to copy the return reg has been emitted.\n\
4159 This functionality can be used to perform special setup of call argument\n\
4160 registers if a target needs it.\n\
4161 For functions without arguments, the hook is called once with @code{pc_rtx}\n\
4162 passed instead of an argument register.\n\
4163 Most ports do not need to implement anything for this hook.",
4169 "This target hook is invoked while generating RTL for a function call,\n\
4170 just after the point where the return reg is copied into a pseudo. It\n\
4171 signals that all the call argument and return registers for the just\n\
4172 emitted call are now no longer in use.\n\
4173 Most ports do not need to implement anything for this hook.",
4178 (strict_argument_naming,
4179 "Define this hook to return @code{true} if the location where a function\n\
4180 argument is passed depends on whether or not it is a named argument.\n\
4182 This hook controls how the @var{named} argument to @code{TARGET_FUNCTION_ARG}\n\
4183 is set for varargs and stdarg functions. If this hook returns\n\
4184 @code{true}, the @var{named} argument is always true for named\n\
4185 arguments, and false for unnamed arguments. If it returns @code{false},\n\
4186 but @code{TARGET_PRETEND_OUTGOING_VARARGS_NAMED} returns @code{true},\n\
4187 then all arguments are treated as named. Otherwise, all named arguments\n\
4188 except the last are treated as named.\n\
4190 You need not define this hook if it always returns @code{false}.",
4191 bool, (cumulative_args_t ca),
4192 hook_bool_CUMULATIVE_ARGS_false)
4194 /* Returns true if we should use
4195 targetm.calls.setup_incoming_varargs() and/or
4196 targetm.calls.strict_argument_naming(). */
4198 (pretend_outgoing_varargs_named,
4199 "If you need to conditionally change ABIs so that one works with\n\
4200 @code{TARGET_SETUP_INCOMING_VARARGS}, but the other works like neither\n\
4201 @code{TARGET_SETUP_INCOMING_VARARGS} nor @code{TARGET_STRICT_ARGUMENT_NAMING} was\n\
4202 defined, then define this hook to return @code{true} if\n\
4203 @code{TARGET_SETUP_INCOMING_VARARGS} is used, @code{false} otherwise.\n\
4204 Otherwise, you should not define this hook.",
4205 bool, (cumulative_args_t ca),
4206 default_pretend_outgoing_varargs_named)
4208 /* Given a complex type T, return true if a parameter of type T
4209 should be passed as two scalars. */
4212 "This hook should return true if parameter of type @var{type} are passed\n\
4213 as two scalar parameters. By default, GCC will attempt to pack complex\n\
4214 arguments into the target's word size. Some ABIs require complex arguments\n\
4215 to be split and treated as their individual components. For example, on\n\
4216 AIX64, complex floats should be passed in a pair of floating point\n\
4217 registers, even though a complex float would fit in one 64-bit floating\n\
4220 The default value of this hook is @code{NULL}, which is treated as always\n\
4222 bool, (const_tree type), NULL)
4224 /* Return true if type T, mode MODE, may not be passed in registers,
4225 but must be passed on the stack. */
4226 /* ??? This predicate should be applied strictly after pass-by-reference.
4227 Need audit to verify that this is the case. */
4229 (must_pass_in_stack,
4230 "This target hook should return @code{true} if we should not pass @var{type}\n\
4231 solely in registers. The file @file{expr.h} defines a\n\
4232 definition that is usually appropriate, refer to @file{expr.h} for additional\n\
4234 bool, (machine_mode mode, const_tree type),
4235 must_pass_in_stack_var_size_or_pad)
4237 /* Return true if type TYPE, mode MODE, which is passed by reference,
4238 should have the object copy generated by the callee rather than
4239 the caller. It is never called for TYPE requiring constructors. */
4242 "The function argument described by the parameters to this hook is\n\
4243 known to be passed by reference. The hook should return true if the\n\
4244 function argument should be copied by the callee instead of copied\n\
4247 For any argument for which the hook returns true, if it can be\n\
4248 determined that the argument is not modified, then a copy need\n\
4249 not be generated.\n\
4251 The default version of this hook always returns false.",
4253 (cumulative_args_t cum, machine_mode mode, const_tree type, bool named),
4254 hook_bool_CUMULATIVE_ARGS_mode_tree_bool_false)
4256 /* Return zero for arguments passed entirely on the stack or entirely
4257 in registers. If passed in both, return the number of bytes passed
4258 in registers; the balance is therefore passed on the stack. */
4261 "This target hook returns the number of bytes at the beginning of an\n\
4262 argument that must be put in registers. The value must be zero for\n\
4263 arguments that are passed entirely in registers or that are entirely\n\
4264 pushed on the stack.\n\
4266 On some machines, certain arguments must be passed partially in\n\
4267 registers and partially in memory. On these machines, typically the\n\
4268 first few words of arguments are passed in registers, and the rest\n\
4269 on the stack. If a multi-word argument (a @code{double} or a\n\
4270 structure) crosses that boundary, its first few words must be passed\n\
4271 in registers and the rest must be pushed. This macro tells the\n\
4272 compiler when this occurs, and how many bytes should go in registers.\n\
4274 @code{TARGET_FUNCTION_ARG} for these arguments should return the first\n\
4275 register to be used by the caller for this argument; likewise\n\
4276 @code{TARGET_FUNCTION_INCOMING_ARG}, for the called function.",
4277 int, (cumulative_args_t cum, machine_mode mode, tree type, bool named),
4278 hook_int_CUMULATIVE_ARGS_mode_tree_bool_0)
4280 /* Update the state in CA to advance past an argument in the
4281 argument list. The values MODE, TYPE, and NAMED describe that
4284 (function_arg_advance,
4285 "This hook updates the summarizer variable pointed to by @var{ca} to\n\
4286 advance past an argument in the argument list. The values @var{mode},\n\
4287 @var{type} and @var{named} describe that argument. Once this is done,\n\
4288 the variable @var{cum} is suitable for analyzing the @emph{following}\n\
4289 argument with @code{TARGET_FUNCTION_ARG}, etc.\n\
4291 This hook need not do anything if the argument in question was passed\n\
4292 on the stack. The compiler knows how to track the amount of stack space\n\
4293 used for arguments without any special help.",
4295 (cumulative_args_t ca, machine_mode mode, const_tree type, bool named),
4296 default_function_arg_advance)
4298 /* Return zero if the argument described by the state of CA should
4299 be placed on a stack, or a hard register in which to store the
4300 argument. The values MODE, TYPE, and NAMED describe that
4304 "Return an RTX indicating whether a function argument is passed in a\n\
4305 register and if so, which register.\n\
4307 The arguments are @var{ca}, which summarizes all the previous\n\
4308 arguments; @var{mode}, the machine mode of the argument; @var{type},\n\
4309 the data type of the argument as a tree node or 0 if that is not known\n\
4310 (which happens for C support library functions); and @var{named},\n\
4311 which is @code{true} for an ordinary argument and @code{false} for\n\
4312 nameless arguments that correspond to @samp{@dots{}} in the called\n\
4313 function's prototype. @var{type} can be an incomplete type if a\n\
4314 syntax error has previously occurred.\n\
4316 The return value is usually either a @code{reg} RTX for the hard\n\
4317 register in which to pass the argument, or zero to pass the argument\n\
4320 The return value can be a @code{const_int} which means argument is\n\
4321 passed in a target specific slot with specified number. Target hooks\n\
4322 should be used to store or load argument in such case. See\n\
4323 @code{TARGET_STORE_BOUNDS_FOR_ARG} and @code{TARGET_LOAD_BOUNDS_FOR_ARG}\n\
4324 for more information.\n\
4326 The value of the expression can also be a @code{parallel} RTX@. This is\n\
4327 used when an argument is passed in multiple locations. The mode of the\n\
4328 @code{parallel} should be the mode of the entire argument. The\n\
4329 @code{parallel} holds any number of @code{expr_list} pairs; each one\n\
4330 describes where part of the argument is passed. In each\n\
4331 @code{expr_list} the first operand must be a @code{reg} RTX for the hard\n\
4332 register in which to pass this part of the argument, and the mode of the\n\
4333 register RTX indicates how large this part of the argument is. The\n\
4334 second operand of the @code{expr_list} is a @code{const_int} which gives\n\
4335 the offset in bytes into the entire argument of where this part starts.\n\
4336 As a special exception the first @code{expr_list} in the @code{parallel}\n\
4337 RTX may have a first operand of zero. This indicates that the entire\n\
4338 argument is also stored on the stack.\n\
4340 The last time this hook is called, it is called with @code{MODE ==\n\
4341 VOIDmode}, and its result is passed to the @code{call} or @code{call_value}\n\
4342 pattern as operands 2 and 3 respectively.\n\
4344 @cindex @file{stdarg.h} and register arguments\n\
4345 The usual way to make the ISO library @file{stdarg.h} work on a\n\
4346 machine where some arguments are usually passed in registers, is to\n\
4347 cause nameless arguments to be passed on the stack instead. This is\n\
4348 done by making @code{TARGET_FUNCTION_ARG} return 0 whenever\n\
4349 @var{named} is @code{false}.\n\
4351 @cindex @code{TARGET_MUST_PASS_IN_STACK}, and @code{TARGET_FUNCTION_ARG}\n\
4352 @cindex @code{REG_PARM_STACK_SPACE}, and @code{TARGET_FUNCTION_ARG}\n\
4353 You may use the hook @code{targetm.calls.must_pass_in_stack}\n\
4354 in the definition of this macro to determine if this argument is of a\n\
4355 type that must be passed in the stack. If @code{REG_PARM_STACK_SPACE}\n\
4356 is not defined and @code{TARGET_FUNCTION_ARG} returns nonzero for such an\n\
4357 argument, the compiler will abort. If @code{REG_PARM_STACK_SPACE} is\n\
4358 defined, the argument will be computed in the stack and then loaded into\n\
4360 rtx, (cumulative_args_t ca, machine_mode mode, const_tree type,
4362 default_function_arg)
4364 /* Likewise, but for machines with register windows. Return the
4365 location where the argument will appear to the callee. */
4367 (function_incoming_arg,
4368 "Define this hook if the target machine has ``register windows'', so\n\
4369 that the register in which a function sees an arguments is not\n\
4370 necessarily the same as the one in which the caller passed the\n\
4373 For such machines, @code{TARGET_FUNCTION_ARG} computes the register in\n\
4374 which the caller passes the value, and\n\
4375 @code{TARGET_FUNCTION_INCOMING_ARG} should be defined in a similar\n\
4376 fashion to tell the function being called where the arguments will\n\
4379 If @code{TARGET_FUNCTION_INCOMING_ARG} is not defined,\n\
4380 @code{TARGET_FUNCTION_ARG} serves both purposes.",
4381 rtx, (cumulative_args_t ca, machine_mode mode, const_tree type,
4383 default_function_incoming_arg)
4386 (function_arg_boundary,
4387 "This hook returns the alignment boundary, in bits, of an argument\n\
4388 with the specified mode and type. The default hook returns\n\
4389 @code{PARM_BOUNDARY} for all arguments.",
4390 unsigned int, (machine_mode mode, const_tree type),
4391 default_function_arg_boundary)
4394 (function_arg_round_boundary,
4395 "Normally, the size of an argument is rounded up to @code{PARM_BOUNDARY},\n\
4396 which is the default value for this hook. You can define this hook to\n\
4397 return a different value if an argument size must be rounded to a larger\n\
4399 unsigned int, (machine_mode mode, const_tree type),
4400 default_function_arg_round_boundary)
4402 /* Return the diagnostic message string if function without a prototype
4403 is not allowed for this 'val' argument; NULL otherwise. */
4405 (invalid_arg_for_unprototyped_fn,
4406 "If defined, this macro returns the diagnostic message when it is\n\
4407 illegal to pass argument @var{val} to function @var{funcdecl}\n\
4408 with prototype @var{typelist}.",
4409 const char *, (const_tree typelist, const_tree funcdecl, const_tree val),
4410 hook_invalid_arg_for_unprototyped_fn)
4412 /* Return an rtx for the return value location of the function
4413 specified by FN_DECL_OR_TYPE with a return type of RET_TYPE. */
4417 Define this to return an RTX representing the place where a function\n\
4418 returns or receives a value of data type @var{ret_type}, a tree node\n\
4419 representing a data type. @var{fn_decl_or_type} is a tree node\n\
4420 representing @code{FUNCTION_DECL} or @code{FUNCTION_TYPE} of a\n\
4421 function being called. If @var{outgoing} is false, the hook should\n\
4422 compute the register in which the caller will see the return value.\n\
4423 Otherwise, the hook should return an RTX representing the place where\n\
4424 a function returns a value.\n\
4426 On many machines, only @code{TYPE_MODE (@var{ret_type})} is relevant.\n\
4427 (Actually, on most machines, scalar values are returned in the same\n\
4428 place regardless of mode.) The value of the expression is usually a\n\
4429 @code{reg} RTX for the hard register where the return value is stored.\n\
4430 The value can also be a @code{parallel} RTX, if the return value is in\n\
4431 multiple places. See @code{TARGET_FUNCTION_ARG} for an explanation of the\n\
4432 @code{parallel} form. Note that the callee will populate every\n\
4433 location specified in the @code{parallel}, but if the first element of\n\
4434 the @code{parallel} contains the whole return value, callers will use\n\
4435 that element as the canonical location and ignore the others. The m68k\n\
4436 port uses this type of @code{parallel} to return pointers in both\n\
4437 @samp{%a0} (the canonical location) and @samp{%d0}.\n\
4439 If @code{TARGET_PROMOTE_FUNCTION_RETURN} returns true, you must apply\n\
4440 the same promotion rules specified in @code{PROMOTE_MODE} if\n\
4441 @var{valtype} is a scalar type.\n\
4443 If the precise function being called is known, @var{func} is a tree\n\
4444 node (@code{FUNCTION_DECL}) for it; otherwise, @var{func} is a null\n\
4445 pointer. This makes it possible to use a different value-returning\n\
4446 convention for specific functions when all their calls are\n\
4449 Some target machines have ``register windows'' so that the register in\n\
4450 which a function returns its value is not the same as the one in which\n\
4451 the caller sees the value. For such machines, you should return\n\
4452 different RTX depending on @var{outgoing}.\n\
4454 @code{TARGET_FUNCTION_VALUE} is not used for return values with\n\
4455 aggregate data types, because these are returned in another way. See\n\
4456 @code{TARGET_STRUCT_VALUE_RTX} and related macros, below.",
4457 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
4458 default_function_value)
4460 /* Return the rtx for bounds of returned pointer. */
4462 (chkp_function_value_bounds,
4463 "Define this to return an RTX representing the place where a function\n\
4464 returns bounds for returned pointers. Arguments meaning is similar to\n\
4465 @code{TARGET_FUNCTION_VALUE}.",
4466 rtx, (const_tree ret_type, const_tree fn_decl_or_type, bool outgoing),
4467 default_chkp_function_value_bounds)
4469 /* Return the rtx for the result of a libcall of mode MODE,
4470 calling the function FN_NAME. */
4473 "Define this hook if the back-end needs to know the name of the libcall\n\
4474 function in order to determine where the result should be returned.\n\
4476 The mode of the result is given by @var{mode} and the name of the called\n\
4477 library function is given by @var{fun}. The hook should return an RTX\n\
4478 representing the place where the library function result will be returned.\n\
4480 If this hook is not defined, then LIBCALL_VALUE will be used.",
4481 rtx, (machine_mode mode, const_rtx fun),
4482 default_libcall_value)
4484 /* Return true if REGNO is a possible register number for
4485 a function value as seen by the caller. */
4487 (function_value_regno_p,
4488 "A target hook that return @code{true} if @var{regno} is the number of a hard\n\
4489 register in which the values of called function may come back.\n\
4491 A register whose use for returning values is limited to serving as the\n\
4492 second of a pair (for a value of type @code{double}, say) need not be\n\
4493 recognized by this target hook.\n\
4495 If the machine has register windows, so that the caller and the called\n\
4496 function use different registers for the return value, this target hook\n\
4497 should recognize only the caller's register numbers.\n\
4499 If this hook is not defined, then FUNCTION_VALUE_REGNO_P will be used.",
4500 bool, (const unsigned int regno),
4501 default_function_value_regno_p)
4503 /* ??? Documenting this hook requires a GFDL license grant. */
4505 (internal_arg_pointer,
4506 "Return an rtx for the argument pointer incoming to the\
4509 default_internal_arg_pointer)
4511 /* Update the current function stack boundary if needed. */
4513 (update_stack_boundary,
4514 "Define this macro to update the current function stack boundary if\n\
4518 /* Handle stack alignment and return an rtx for Dynamic Realign
4519 Argument Pointer if necessary. */
4522 "This hook should return an rtx for Dynamic Realign Argument Pointer (DRAP) if a\n\
4523 different argument pointer register is needed to access the function's\n\
4524 argument list due to stack realignment. Return @code{NULL} if no DRAP\n\
4528 /* Return true if all function parameters should be spilled to the
4531 (allocate_stack_slots_for_args,
4532 "When optimization is disabled, this hook indicates whether or not\n\
4533 arguments should be allocated to stack slots. Normally, GCC allocates\n\
4534 stacks slots for arguments when not optimizing in order to make\n\
4535 debugging easier. However, when a function is declared with\n\
4536 @code{__attribute__((naked))}, there is no stack frame, and the compiler\n\
4537 cannot safely move arguments from the registers in which they are passed\n\
4538 to the stack. Therefore, this hook should return true in general, but\n\
4539 false for naked functions. The default implementation always returns true.",
4541 hook_bool_void_true)
4543 /* Return an rtx for the static chain for FNDECL_OR_TYPE. If INCOMING_P
4544 is true, then it should be for the callee; otherwise for the caller. */
4547 "This hook replaces the use of @code{STATIC_CHAIN_REGNUM} et al for\n\
4548 targets that may use different static chain locations for different\n\
4549 nested functions. This may be required if the target has function\n\
4550 attributes that affect the calling conventions of the function and\n\
4551 those calling conventions use different static chain locations.\n\
4553 The default version of this hook uses @code{STATIC_CHAIN_REGNUM} et al.\n\
4555 If the static chain is passed in memory, this hook should be used to\n\
4556 provide rtx giving @code{mem} expressions that denote where they are stored.\n\
4557 Often the @code{mem} expression as seen by the caller will be at an offset\n\
4558 from the stack pointer and the @code{mem} expression as seen by the callee\n\
4559 will be at an offset from the frame pointer.\n\
4560 @findex stack_pointer_rtx\n\
4561 @findex frame_pointer_rtx\n\
4562 @findex arg_pointer_rtx\n\
4563 The variables @code{stack_pointer_rtx}, @code{frame_pointer_rtx}, and\n\
4564 @code{arg_pointer_rtx} will have been initialized and should be used\n\
4565 to refer to those items.",
4566 rtx, (const_tree fndecl_or_type, bool incoming_p),
4567 default_static_chain)
4569 /* Fill in the trampoline at MEM with a call to FNDECL and a
4570 static chain value of CHAIN. */
4573 "This hook is called to initialize a trampoline.\n\
4574 @var{m_tramp} is an RTX for the memory block for the trampoline; @var{fndecl}\n\
4575 is the @code{FUNCTION_DECL} for the nested function; @var{static_chain} is an\n\
4576 RTX for the static chain value that should be passed to the function\n\
4577 when it is called.\n\
4579 If the target defines @code{TARGET_ASM_TRAMPOLINE_TEMPLATE}, then the\n\
4580 first thing this hook should do is emit a block move into @var{m_tramp}\n\
4581 from the memory block returned by @code{assemble_trampoline_template}.\n\
4582 Note that the block move need only cover the constant parts of the\n\
4583 trampoline. If the target isolates the variable parts of the trampoline\n\
4584 to the end, not all @code{TRAMPOLINE_SIZE} bytes need be copied.\n\
4586 If the target requires any other actions, such as flushing caches or\n\
4587 enabling stack execution, these actions should be performed after\n\
4588 initializing the trampoline proper.",
4589 void, (rtx m_tramp, tree fndecl, rtx static_chain),
4590 default_trampoline_init)
4592 /* Adjust the address of the trampoline in a target-specific way. */
4594 (trampoline_adjust_address,
4595 "This hook should perform any machine-specific adjustment in\n\
4596 the address of the trampoline. Its argument contains the address of the\n\
4597 memory block that was passed to @code{TARGET_TRAMPOLINE_INIT}. In case\n\
4598 the address to be used for a function call should be different from the\n\
4599 address at which the template was stored, the different address should\n\
4600 be returned; otherwise @var{addr} should be returned unchanged.\n\
4601 If this hook is not defined, @var{addr} will be used for function calls.",
4602 rtx, (rtx addr), NULL)
4604 /* Return the number of bytes of its own arguments that a function
4605 pops on returning, or 0 if the function pops no arguments and the
4606 caller must therefore pop them all after the function returns. */
4607 /* ??? tm.texi has no types for the parameters. */
4610 "This target hook returns the number of bytes of its own arguments that\n\
4611 a function pops on returning, or 0 if the function pops no arguments\n\
4612 and the caller must therefore pop them all after the function returns.\n\
4614 @var{fundecl} is a C variable whose value is a tree node that describes\n\
4615 the function in question. Normally it is a node of type\n\
4616 @code{FUNCTION_DECL} that describes the declaration of the function.\n\
4617 From this you can obtain the @code{DECL_ATTRIBUTES} of the function.\n\
4619 @var{funtype} is a C variable whose value is a tree node that\n\
4620 describes the function in question. Normally it is a node of type\n\
4621 @code{FUNCTION_TYPE} that describes the data type of the function.\n\
4622 From this it is possible to obtain the data types of the value and\n\
4623 arguments (if known).\n\
4625 When a call to a library function is being considered, @var{fundecl}\n\
4626 will contain an identifier node for the library function. Thus, if\n\
4627 you need to distinguish among various library functions, you can do so\n\
4628 by their names. Note that ``library function'' in this context means\n\
4629 a function used to perform arithmetic, whose name is known specially\n\
4630 in the compiler and was not mentioned in the C code being compiled.\n\
4632 @var{size} is the number of bytes of arguments passed on the\n\
4633 stack. If a variable number of bytes is passed, it is zero, and\n\
4634 argument popping will always be the responsibility of the calling function.\n\
4636 On the VAX, all functions always pop their arguments, so the definition\n\
4637 of this macro is @var{size}. On the 68000, using the standard\n\
4638 calling convention, no functions pop their arguments, so the value of\n\
4639 the macro is always 0 in this case. But an alternative calling\n\
4640 convention is available in which functions that take a fixed number of\n\
4641 arguments pop them but other functions (such as @code{printf}) pop\n\
4642 nothing (the caller pops all). When this convention is in use,\n\
4643 @var{funtype} is examined to determine whether a function takes a fixed\n\
4644 number of arguments.",
4645 int, (tree fundecl, tree funtype, int size),
4646 default_return_pops_args)
4648 /* Return a mode wide enough to copy any function value that might be
4651 (get_raw_result_mode,
4652 "This target hook returns the mode to be used when accessing raw return\
4653 registers in @code{__builtin_return}. Define this macro if the value\
4654 in @var{reg_raw_mode} is not correct.",
4655 machine_mode, (int regno),
4656 default_get_reg_raw_mode)
4658 /* Return a mode wide enough to copy any argument value that might be
4662 "This target hook returns the mode to be used when accessing raw argument\
4663 registers in @code{__builtin_apply_args}. Define this macro if the value\
4664 in @var{reg_raw_mode} is not correct.",
4665 machine_mode, (int regno),
4666 default_get_reg_raw_mode)
4668 HOOK_VECTOR_END (calls)
4671 (use_pseudo_pic_reg,
4672 "This hook should return 1 in case pseudo register should be created\n\
4673 for pic_offset_table_rtx during function expand.",
4675 hook_bool_void_false)
4679 "Perform a target dependent initialization of pic_offset_table_rtx.\n\
4680 This hook is called at the start of register allocation.",
4684 /* Return the diagnostic message string if conversion from FROMTYPE
4685 to TOTYPE is not allowed, NULL otherwise. */
4687 (invalid_conversion,
4688 "If defined, this macro returns the diagnostic message when it is\n\
4689 invalid to convert from @var{fromtype} to @var{totype}, or @code{NULL}\n\
4690 if validity should be determined by the front end.",
4691 const char *, (const_tree fromtype, const_tree totype),
4692 hook_constcharptr_const_tree_const_tree_null)
4694 /* Return the diagnostic message string if the unary operation OP is
4695 not permitted on TYPE, NULL otherwise. */
4698 "If defined, this macro returns the diagnostic message when it is\n\
4699 invalid to apply operation @var{op} (where unary plus is denoted by\n\
4700 @code{CONVERT_EXPR}) to an operand of type @var{type}, or @code{NULL}\n\
4701 if validity should be determined by the front end.",
4702 const char *, (int op, const_tree type),
4703 hook_constcharptr_int_const_tree_null)
4705 /* Return the diagnostic message string if the binary operation OP
4706 is not permitted on TYPE1 and TYPE2, NULL otherwise. */
4709 "If defined, this macro returns the diagnostic message when it is\n\
4710 invalid to apply operation @var{op} to operands of types @var{type1}\n\
4711 and @var{type2}, or @code{NULL} if validity should be determined by\n\
4713 const char *, (int op, const_tree type1, const_tree type2),
4714 hook_constcharptr_int_const_tree_const_tree_null)
4716 /* Return the diagnostic message string if TYPE is not valid as a
4717 function parameter type, NULL otherwise. */
4719 (invalid_parameter_type,
4720 "If defined, this macro returns the diagnostic message when it is\n\
4721 invalid for functions to include parameters of type @var{type},\n\
4722 or @code{NULL} if validity should be determined by\n\
4723 the front end. This is currently used only by the C and C++ front ends.",
4724 const char *, (const_tree type),
4725 hook_constcharptr_const_tree_null)
4727 /* Return the diagnostic message string if TYPE is not valid as a
4728 function return type, NULL otherwise. */
4730 (invalid_return_type,
4731 "If defined, this macro returns the diagnostic message when it is\n\
4732 invalid for functions to have return type @var{type},\n\
4733 or @code{NULL} if validity should be determined by\n\
4734 the front end. This is currently used only by the C and C++ front ends.",
4735 const char *, (const_tree type),
4736 hook_constcharptr_const_tree_null)
4738 /* If values of TYPE are promoted to some other type when used in
4739 expressions (analogous to the integer promotions), return that type,
4740 or NULL_TREE otherwise. */
4743 "If defined, this target hook returns the type to which values of\n\
4744 @var{type} should be promoted when they appear in expressions,\n\
4745 analogous to the integer promotions, or @code{NULL_TREE} to use the\n\
4746 front end's normal promotion rules. This hook is useful when there are\n\
4747 target-specific types with special promotion rules.\n\
4748 This is currently used only by the C and C++ front ends.",
4749 tree, (const_tree type),
4750 hook_tree_const_tree_null)
4752 /* Convert EXPR to TYPE, if target-specific types with special conversion
4753 rules are involved. Return the converted expression, or NULL to apply
4754 the standard conversion rules. */
4757 "If defined, this hook returns the result of converting @var{expr} to\n\
4758 @var{type}. It should return the converted expression,\n\
4759 or @code{NULL_TREE} to apply the front end's normal conversion rules.\n\
4760 This hook is useful when there are target-specific types with special\n\
4761 conversion rules.\n\
4762 This is currently used only by the C and C++ front ends.",
4763 tree, (tree type, tree expr),
4764 hook_tree_tree_tree_null)
4766 /* Change pseudo allocno class calculated by IRA. */
4768 (ira_change_pseudo_allocno_class,
4769 "A target hook which can change allocno class for given pseudo from\n\
4770 allocno class calculated by IRA.\n\
4772 The default version of this target hook always returns given class.",
4773 reg_class_t, (int, reg_class_t),
4774 default_ira_change_pseudo_allocno_class)
4776 /* Return true if we use LRA instead of reload. */
4779 "A target hook which returns true if we use LRA instead of reload pass.\
4780 It means that LRA was ported to the target.\
4782 The default version of this target hook returns always false.",
4786 /* Return register priority of given hard regno for the current target. */
4789 "A target hook which returns the register priority number to which the\
4790 register @var{hard_regno} belongs to. The bigger the number, the\
4791 more preferable the hard register usage (when all other conditions are\
4792 the same). This hook can be used to prefer some hard register over\
4793 others in LRA. For example, some x86-64 register usage needs\
4794 additional prefix which makes instructions longer. The hook can\
4795 return lower priority number for such registers make them less favorable\
4796 and as result making the generated code smaller.\
4798 The default version of this target hook returns always zero.",
4800 default_register_priority)
4802 /* Return true if we need register usage leveling. */
4804 (register_usage_leveling_p,
4805 "A target hook which returns true if we need register usage leveling.\
4806 That means if a few hard registers are equally good for the\
4807 assignment, we choose the least used hard register. The register\
4808 usage leveling may be profitable for some targets. Don't use the\
4809 usage leveling for targets with conditional execution or targets\
4810 with big register files as it hurts if-conversion and cross-jumping\
4813 The default version of this target hook returns always false.",
4815 default_register_usage_leveling_p)
4817 /* Return true if maximal address displacement can be different. */
4819 (different_addr_displacement_p,
4820 "A target hook which returns true if an address with the same structure\
4821 can have different maximal legitimate displacement. For example, the\
4822 displacement can depend on memory mode or on operand combinations in\
4825 The default version of this target hook returns always false.",
4827 default_different_addr_displacement_p)
4829 /* Determine class for spilling pseudos of given mode into registers
4830 instead of memory. */
4833 "This hook defines a class of registers which could be used for spilling\
4834 pseudos of the given mode and class, or @code{NO_REGS} if only memory\
4835 should be used. Not defining this hook is equivalent to returning\
4836 @code{NO_REGS} for all inputs.",
4837 reg_class_t, (reg_class_t, machine_mode),
4842 "This hook defines the machine mode to use for the boolean result of\
4843 conditional store patterns. The ICODE argument is the instruction code\
4844 for the cstore being performed. Not definiting this hook is the same\
4845 as accepting the mode encoded into operand 0 of the cstore expander\
4847 machine_mode, (enum insn_code icode),
4848 default_cstore_mode)
4850 /* True if a structure, union or array with MODE containing FIELD should
4851 be accessed using BLKmode. */
4853 (member_type_forces_blk,
4854 "Return true if a structure, union or array containing @var{field} should\n\
4855 be accessed using @code{BLKMODE}.\n\
4857 If @var{field} is the only field in the structure, @var{mode} is its\n\
4858 mode, otherwise @var{mode} is VOIDmode. @var{mode} is provided in the\n\
4859 case where structures of one field would require the structure's mode to\n\
4860 retain the field's mode.\n\
4862 Normally, this is not needed.",
4863 bool, (const_tree field, machine_mode mode),
4864 default_member_type_forces_blk)
4866 /* Return the class for a secondary reload, and fill in extra information. */
4869 "Many machines have some registers that cannot be copied directly to or\n\
4870 from memory or even from other types of registers. An example is the\n\
4871 @samp{MQ} register, which on most machines, can only be copied to or\n\
4872 from general registers, but not memory. Below, we shall be using the\n\
4873 term 'intermediate register' when a move operation cannot be performed\n\
4874 directly, but has to be done by copying the source into the intermediate\n\
4875 register first, and then copying the intermediate register to the\n\
4876 destination. An intermediate register always has the same mode as\n\
4877 source and destination. Since it holds the actual value being copied,\n\
4878 reload might apply optimizations to re-use an intermediate register\n\
4879 and eliding the copy from the source when it can determine that the\n\
4880 intermediate register still holds the required value.\n\
4882 Another kind of secondary reload is required on some machines which\n\
4883 allow copying all registers to and from memory, but require a scratch\n\
4884 register for stores to some memory locations (e.g., those with symbolic\n\
4885 address on the RT, and those with certain symbolic address on the SPARC\n\
4886 when compiling PIC)@. Scratch registers need not have the same mode\n\
4887 as the value being copied, and usually hold a different value than\n\
4888 that being copied. Special patterns in the md file are needed to\n\
4889 describe how the copy is performed with the help of the scratch register;\n\
4890 these patterns also describe the number, register class(es) and mode(s)\n\
4891 of the scratch register(s).\n\
4893 In some cases, both an intermediate and a scratch register are required.\n\
4895 For input reloads, this target hook is called with nonzero @var{in_p},\n\
4896 and @var{x} is an rtx that needs to be copied to a register of class\n\
4897 @var{reload_class} in @var{reload_mode}. For output reloads, this target\n\
4898 hook is called with zero @var{in_p}, and a register of class @var{reload_class}\n\
4899 needs to be copied to rtx @var{x} in @var{reload_mode}.\n\
4901 If copying a register of @var{reload_class} from/to @var{x} requires\n\
4902 an intermediate register, the hook @code{secondary_reload} should\n\
4903 return the register class required for this intermediate register.\n\
4904 If no intermediate register is required, it should return NO_REGS.\n\
4905 If more than one intermediate register is required, describe the one\n\
4906 that is closest in the copy chain to the reload register.\n\
4908 If scratch registers are needed, you also have to describe how to\n\
4909 perform the copy from/to the reload register to/from this\n\
4910 closest intermediate register. Or if no intermediate register is\n\
4911 required, but still a scratch register is needed, describe the\n\
4912 copy from/to the reload register to/from the reload operand @var{x}.\n\
4914 You do this by setting @code{sri->icode} to the instruction code of a pattern\n\
4915 in the md file which performs the move. Operands 0 and 1 are the output\n\
4916 and input of this copy, respectively. Operands from operand 2 onward are\n\
4917 for scratch operands. These scratch operands must have a mode, and a\n\
4918 single-register-class\n\
4919 @c [later: or memory]\n\
4920 output constraint.\n\
4922 When an intermediate register is used, the @code{secondary_reload}\n\
4923 hook will be called again to determine how to copy the intermediate\n\
4924 register to/from the reload operand @var{x}, so your hook must also\n\
4925 have code to handle the register class of the intermediate operand.\n\
4927 @c [For later: maybe we'll allow multi-alternative reload patterns -\n\
4928 @c the port maintainer could name a mov<mode> pattern that has clobbers -\n\
4929 @c and match the constraints of input and output to determine the required\n\
4930 @c alternative. A restriction would be that constraints used to match\n\
4931 @c against reloads registers would have to be written as register class\n\
4932 @c constraints, or we need a new target macro / hook that tells us if an\n\
4933 @c arbitrary constraint can match an unknown register of a given class.\n\
4934 @c Such a macro / hook would also be useful in other places.]\n\
4937 @var{x} might be a pseudo-register or a @code{subreg} of a\n\
4938 pseudo-register, which could either be in a hard register or in memory.\n\
4939 Use @code{true_regnum} to find out; it will return @minus{}1 if the pseudo is\n\
4940 in memory and the hard register number if it is in a register.\n\
4942 Scratch operands in memory (constraint @code{\"=m\"} / @code{\"=&m\"}) are\n\
4943 currently not supported. For the time being, you will have to continue\n\
4944 to use @code{SECONDARY_MEMORY_NEEDED} for that purpose.\n\
4946 @code{copy_cost} also uses this target hook to find out how values are\n\
4947 copied. If you want it to include some extra cost for the need to allocate\n\
4948 (a) scratch register(s), set @code{sri->extra_cost} to the additional cost.\n\
4949 Or if two dependent moves are supposed to have a lower cost than the sum\n\
4950 of the individual moves due to expected fortuitous scheduling and/or special\n\
4951 forwarding logic, you can set @code{sri->extra_cost} to a negative amount.",
4953 (bool in_p, rtx x, reg_class_t reload_class, machine_mode reload_mode,
4954 secondary_reload_info *sri),
4955 default_secondary_reload)
4957 /* Given an rtx X being reloaded into a reg required to be in class CLASS,
4958 return the class of reg to actually use. */
4960 (preferred_reload_class,
4961 "A target hook that places additional restrictions on the register class\n\
4962 to use when it is necessary to copy value @var{x} into a register in class\n\
4963 @var{rclass}. The value is a register class; perhaps @var{rclass}, or perhaps\n\
4964 another, smaller class.\n\
4966 The default version of this hook always returns value of @code{rclass} argument.\n\
4968 Sometimes returning a more restrictive class makes better code. For\n\
4969 example, on the 68000, when @var{x} is an integer constant that is in range\n\
4970 for a @samp{moveq} instruction, the value of this macro is always\n\
4971 @code{DATA_REGS} as long as @var{rclass} includes the data registers.\n\
4972 Requiring a data register guarantees that a @samp{moveq} will be used.\n\
4974 One case where @code{TARGET_PREFERRED_RELOAD_CLASS} must not return\n\
4975 @var{rclass} is if @var{x} is a legitimate constant which cannot be\n\
4976 loaded into some register class. By returning @code{NO_REGS} you can\n\
4977 force @var{x} into a memory location. For example, rs6000 can load\n\
4978 immediate values into general-purpose registers, but does not have an\n\
4979 instruction for loading an immediate value into a floating-point\n\
4980 register, so @code{TARGET_PREFERRED_RELOAD_CLASS} returns @code{NO_REGS} when\n\
4981 @var{x} is a floating-point constant. If the constant can't be loaded\n\
4982 into any kind of register, code generation will be better if\n\
4983 @code{TARGET_LEGITIMATE_CONSTANT_P} makes the constant illegitimate instead\n\
4984 of using @code{TARGET_PREFERRED_RELOAD_CLASS}.\n\
4986 If an insn has pseudos in it after register allocation, reload will go\n\
4987 through the alternatives and call repeatedly @code{TARGET_PREFERRED_RELOAD_CLASS}\n\
4988 to find the best one. Returning @code{NO_REGS}, in this case, makes\n\
4989 reload add a @code{!} in front of the constraint: the x86 back-end uses\n\
4990 this feature to discourage usage of 387 registers when math is done in\n\
4991 the SSE registers (and vice versa).",
4993 (rtx x, reg_class_t rclass),
4994 default_preferred_reload_class)
4996 /* Like TARGET_PREFERRED_RELOAD_CLASS, but for output reloads instead of
4999 (preferred_output_reload_class,
5000 "Like @code{TARGET_PREFERRED_RELOAD_CLASS}, but for output reloads instead of\n\
5003 The default version of this hook always returns value of @code{rclass}\n\
5006 You can also use @code{TARGET_PREFERRED_OUTPUT_RELOAD_CLASS} to discourage\n\
5007 reload from using some alternatives, like @code{TARGET_PREFERRED_RELOAD_CLASS}.",
5009 (rtx x, reg_class_t rclass),
5010 default_preferred_output_reload_class)
5013 (class_likely_spilled_p,
5014 "A target hook which returns @code{true} if pseudos that have been assigned\n\
5015 to registers of class @var{rclass} would likely be spilled because\n\
5016 registers of @var{rclass} are needed for spill registers.\n\
5018 The default version of this target hook returns @code{true} if @var{rclass}\n\
5019 has exactly one register and @code{false} otherwise. On most machines, this\n\
5020 default should be used. For generally register-starved machines, such as\n\
5021 i386, or machines with right register constraints, such as SH, this hook\n\
5022 can be used to avoid excessive spilling.\n\
5024 This hook is also used by some of the global intra-procedural code\n\
5025 transformations to throtle code motion, to avoid increasing register\n\
5027 bool, (reg_class_t rclass),
5028 default_class_likely_spilled_p)
5030 /* Return the maximum number of consecutive registers
5031 needed to represent mode MODE in a register of class RCLASS. */
5034 "A target hook returns the maximum number of consecutive registers\n\
5035 of class @var{rclass} needed to hold a value of mode @var{mode}.\n\
5037 This is closely related to the macro @code{HARD_REGNO_NREGS}. In fact,\n\
5038 the value returned by @code{TARGET_CLASS_MAX_NREGS (@var{rclass},\n\
5039 @var{mode})} target hook should be the maximum value of\n\
5040 @code{HARD_REGNO_NREGS (@var{regno}, @var{mode})} for all @var{regno}\n\
5041 values in the class @var{rclass}.\n\
5043 This target hook helps control the handling of multiple-word values\n\
5044 in the reload pass.\n\
5046 The default version of this target hook returns the size of @var{mode}\n\
5048 unsigned char, (reg_class_t rclass, machine_mode mode),
5049 default_class_max_nregs)
5052 (preferred_rename_class,
5053 "A target hook that places additional preference on the register\
5054 class to use when it is necessary to rename a register in class\
5055 @var{rclass} to another class, or perhaps @var{NO_REGS}, if no\
5056 preferred register class is found or hook @code{preferred_rename_class}\
5057 is not implemented.\
5058 Sometimes returning a more restrictive class makes better code. For\
5059 example, on ARM, thumb-2 instructions using @code{LO_REGS} may be\
5060 smaller than instructions using @code{GENERIC_REGS}. By returning\
5061 @code{LO_REGS} from @code{preferred_rename_class}, code size can\
5063 reg_class_t, (reg_class_t rclass),
5064 default_preferred_rename_class)
5066 /* This target hook allows the backend to avoid unsafe substitution
5067 during register allocation. */
5069 (cannot_substitute_mem_equiv_p,
5070 "A target hook which returns @code{true} if @var{subst} can't\n\
5071 substitute safely pseudos with equivalent memory values during\n\
5072 register allocation.\n\
5073 The default version of this target hook returns @code{false}.\n\
5074 On most machines, this default should be used. For generally\n\
5075 machines with non orthogonal register usage for addressing, such\n\
5076 as SH, this hook can be used to avoid excessive spilling.",
5078 hook_bool_rtx_false)
5080 /* This target hook allows the backend to legitimize base plus
5081 displacement addressing. */
5083 (legitimize_address_displacement,
5084 "A target hook which returns @code{true} if *@var{disp} is\n\
5085 legitimezed to valid address displacement with subtracting *@var{offset}\n\
5086 at memory mode @var{mode}.\n\
5087 The default version of this target hook returns @code{false}.\n\
5088 This hook will benefit machines with limited base plus displacement\n\
5090 bool, (rtx *disp, rtx *offset, machine_mode mode),
5091 default_legitimize_address_displacement)
5093 /* This target hook allows the backend to perform additional
5094 processing while initializing for variable expansion. */
5096 (expand_to_rtl_hook,
5097 "This hook is called just before expansion into rtl, allowing the target\n\
5098 to perform additional initializations or analysis before the expansion.\n\
5099 For example, the rs6000 port uses it to allocate a scratch stack slot\n\
5100 for use in copying SDmode values between memory and floating point\n\
5101 registers whenever the function being expanded has any SDmode\n\
5106 /* This target hook allows the backend to perform additional
5107 instantiations on rtx that are not actually in insns yet,
5108 but will be later. */
5111 "This hook allows the backend to perform additional instantiations on rtl\n\
5112 that are not actually in any insns yet, but will be later.",
5116 /* Return true if is OK to use a hard register REGNO as scratch register
5119 (hard_regno_scratch_ok,
5120 "This target hook should return @code{true} if it is OK to use a hard register\n\
5121 @var{regno} as scratch reg in peephole2.\n\
5123 One common use of this macro is to prevent using of a register that\n\
5124 is not saved by a prologue in an interrupt handler.\n\
5126 The default version of this hook always returns @code{true}.",
5127 bool, (unsigned int regno),
5128 default_hard_regno_scratch_ok)
5130 /* Return the smallest number of different values for which it is best to
5131 use a jump-table instead of a tree of conditional branches. */
5133 (case_values_threshold,
5134 "This function return the smallest number of different values for which it\n\
5135 is best to use a jump-table instead of a tree of conditional branches.\n\
5136 The default is four for machines with a @code{casesi} instruction and\n\
5137 five otherwise. This is best for most machines.",
5138 unsigned int, (void),
5139 default_case_values_threshold)
5141 /* Retutn true if a function must have and use a frame pointer. */
5143 (frame_pointer_required,
5144 "This target hook should return @code{true} if a function must have and use\n\
5145 a frame pointer. This target hook is called in the reload pass. If its return\n\
5146 value is @code{true} the function will have a frame pointer.\n\
5148 This target hook can in principle examine the current function and decide\n\
5149 according to the facts, but on most machines the constant @code{false} or the\n\
5150 constant @code{true} suffices. Use @code{false} when the machine allows code\n\
5151 to be generated with no frame pointer, and doing so saves some time or space.\n\
5152 Use @code{true} when there is no possible advantage to avoiding a frame\n\
5155 In certain cases, the compiler does not know how to produce valid code\n\
5156 without a frame pointer. The compiler recognizes those cases and\n\
5157 automatically gives the function a frame pointer regardless of what\n\
5158 @code{TARGET_FRAME_POINTER_REQUIRED} returns. You don't need to worry about\n\
5161 In a function that does not require a frame pointer, the frame pointer\n\
5162 register can be allocated for ordinary usage, unless you mark it as a\n\
5163 fixed register. See @code{FIXED_REGISTERS} for more information.\n\
5165 Default return value is @code{false}.",
5167 hook_bool_void_false)
5169 /* Returns true if the compiler is allowed to try to replace register number
5170 from-reg with register number to-reg. */
5173 "This target hook should returns @code{true} if the compiler is allowed to\n\
5174 try to replace register number @var{from_reg} with register number\n\
5175 @var{to_reg}. This target hook need only be defined if @code{ELIMINABLE_REGS}\n\
5176 is defined, and will usually be @code{true}, since most of the cases\n\
5177 preventing register elimination are things that the compiler already\n\
5180 Default return value is @code{true}.",
5181 bool, (const int from_reg, const int to_reg),
5182 hook_bool_const_int_const_int_true)
5184 /* Modify any or all of fixed_regs, call_used_regs, global_regs,
5185 reg_names, and reg_class_contents to account of the vagaries of the
5188 (conditional_register_usage,
5189 "This hook may conditionally modify five variables\n\
5190 @code{fixed_regs}, @code{call_used_regs}, @code{global_regs},\n\
5191 @code{reg_names}, and @code{reg_class_contents}, to take into account\n\
5192 any dependence of these register sets on target flags. The first three\n\
5193 of these are of type @code{char []} (interpreted as Boolean vectors).\n\
5194 @code{global_regs} is a @code{const char *[]}, and\n\
5195 @code{reg_class_contents} is a @code{HARD_REG_SET}. Before the macro is\n\
5196 called, @code{fixed_regs}, @code{call_used_regs},\n\
5197 @code{reg_class_contents}, and @code{reg_names} have been initialized\n\
5198 from @code{FIXED_REGISTERS}, @code{CALL_USED_REGISTERS},\n\
5199 @code{REG_CLASS_CONTENTS}, and @code{REGISTER_NAMES}, respectively.\n\
5200 @code{global_regs} has been cleared, and any @option{-ffixed-@var{reg}},\n\
5201 @option{-fcall-used-@var{reg}} and @option{-fcall-saved-@var{reg}}\n\
5202 command options have been applied.\n\
5204 @cindex disabling certain registers\n\
5205 @cindex controlling register usage\n\
5206 If the usage of an entire class of registers depends on the target\n\
5207 flags, you may indicate this to GCC by using this macro to modify\n\
5208 @code{fixed_regs} and @code{call_used_regs} to 1 for each of the\n\
5209 registers in the classes which should not be used by GCC@. Also make\n\
5210 @code{define_register_constraint}s return @code{NO_REGS} for constraints\n\
5211 that shouldn't be used.\n\
5213 (However, if this class is not included in @code{GENERAL_REGS} and all\n\
5214 of the insn patterns whose constraints permit this class are\n\
5215 controlled by target switches, then GCC will automatically avoid using\n\
5216 these registers when the target switches are opposed to them.)",
5220 /* Functions specific to the C family of frontends. */
5222 #define HOOK_PREFIX "TARGET_C_"
5223 HOOK_VECTOR (TARGET_C, c)
5225 /* ??? Documenting this hook requires a GFDL license grant. */
5228 "Return machine mode for non-standard constant literal suffix @var{c},\
5229 or VOIDmode if non-standard suffixes are unsupported.",
5230 machine_mode, (char c),
5231 default_mode_for_suffix)
5235 /* Functions specific to the C++ frontend. */
5237 #define HOOK_PREFIX "TARGET_CXX_"
5238 HOOK_VECTOR (TARGET_CXX, cxx)
5240 /* Return the integer type used for guard variables. */
5243 "Define this hook to override the integer type used for guard variables.\n\
5244 These are used to implement one-time construction of static objects. The\n\
5245 default is long_long_integer_type_node.",
5247 default_cxx_guard_type)
5249 /* Return true if only the low bit of the guard should be tested. */
5252 "This hook determines how guard variables are used. It should return\n\
5253 @code{false} (the default) if the first byte should be used. A return value of\n\
5254 @code{true} indicates that only the least significant bit should be used.",
5256 hook_bool_void_false)
5258 /* Returns the size of the array cookie for an array of type. */
5261 "This hook returns the size of the cookie to use when allocating an array\n\
5262 whose elements have the indicated @var{type}. Assumes that it is already\n\
5263 known that a cookie is needed. The default is\n\
5264 @code{max(sizeof (size_t), alignof(type))}, as defined in section 2.7 of the\n\
5265 IA64/Generic C++ ABI@.",
5267 default_cxx_get_cookie_size)
5269 /* Returns true if the element size should be stored in the array cookie. */
5272 "This hook should return @code{true} if the element size should be stored in\n\
5273 array cookies. The default is to return @code{false}.",
5275 hook_bool_void_false)
5277 /* Allows backends to perform additional processing when
5278 deciding if a class should be exported or imported. */
5280 (import_export_class,
5281 "If defined by a backend this hook allows the decision made to export\n\
5282 class @var{type} to be overruled. Upon entry @var{import_export}\n\
5283 will contain 1 if the class is going to be exported, @minus{}1 if it is going\n\
5284 to be imported and 0 otherwise. This function should return the\n\
5285 modified value and perform any other actions necessary to support the\n\
5286 backend's targeted operating system.",
5287 int, (tree type, int import_export), NULL)
5289 /* Returns true if constructors and destructors return "this". */
5291 (cdtor_returns_this,
5292 "This hook should return @code{true} if constructors and destructors return\n\
5293 the address of the object created/destroyed. The default is to return\n\
5296 hook_bool_void_false)
5298 /* Returns true if the key method for a class can be an inline
5299 function, so long as it is not declared inline in the class
5300 itself. Returning true is the behavior required by the Itanium C++ ABI. */
5302 (key_method_may_be_inline,
5303 "This hook returns true if the key method for a class (i.e., the method\n\
5304 which, if defined in the current translation unit, causes the virtual\n\
5305 table to be emitted) may be an inline function. Under the standard\n\
5306 Itanium C++ ABI the key method may be an inline function so long as\n\
5307 the function is not declared inline in the class definition. Under\n\
5308 some variants of the ABI, an inline function can never be the key\n\
5309 method. The default is to return @code{true}.",
5311 hook_bool_void_true)
5314 (determine_class_data_visibility,
5315 "@var{decl} is a virtual table, virtual table table, typeinfo object,\
5316 or other similar implicit class data object that will be emitted with\
5317 external linkage in this translation unit. No ELF visibility has been\
5318 explicitly specified. If the target needs to specify a visibility\
5319 other than that of the containing class, use this hook to set\
5320 @code{DECL_VISIBILITY} and @code{DECL_VISIBILITY_SPECIFIED}.",
5324 /* Returns true (the default) if virtual tables and other
5325 similar implicit class data objects are always COMDAT if they
5326 have external linkage. If this hook returns false, then
5327 class data for classes whose virtual table will be emitted in
5328 only one translation unit will not be COMDAT. */
5330 (class_data_always_comdat,
5331 "This hook returns true (the default) if virtual tables and other\n\
5332 similar implicit class data objects are always COMDAT if they have\n\
5333 external linkage. If this hook returns false, then class data for\n\
5334 classes whose virtual table will be emitted in only one translation\n\
5335 unit will not be COMDAT.",
5337 hook_bool_void_true)
5339 /* Returns true (the default) if the RTTI for the basic types,
5340 which is always defined in the C++ runtime, should be COMDAT;
5341 false if it should not be COMDAT. */
5343 (library_rtti_comdat,
5344 "This hook returns true (the default) if the RTTI information for\n\
5345 the basic types which is defined in the C++ runtime should always\n\
5346 be COMDAT, false if it should not be COMDAT.",
5348 hook_bool_void_true)
5350 /* Returns true if __aeabi_atexit should be used to register static
5354 "This hook returns true if @code{__aeabi_atexit} (as defined by the ARM EABI)\n\
5355 should be used to register static destructors when @option{-fuse-cxa-atexit}\n\
5356 is in effect. The default is to return false to use @code{__cxa_atexit}.",
5358 hook_bool_void_false)
5360 /* Returns true if target may use atexit in the same manner as
5361 __cxa_atexit to register static destructors. */
5363 (use_atexit_for_cxa_atexit,
5364 "This hook returns true if the target @code{atexit} function can be used\n\
5365 in the same manner as @code{__cxa_atexit} to register C++ static\n\
5366 destructors. This requires that @code{atexit}-registered functions in\n\
5367 shared libraries are run in the correct order when the libraries are\n\
5368 unloaded. The default is to return false.",
5370 hook_bool_void_false)
5373 (adjust_class_at_definition,
5374 "@var{type} is a C++ class (i.e., RECORD_TYPE or UNION_TYPE) that has just\
5375 been defined. Use this hook to make adjustments to the class (eg, tweak\
5376 visibility or perform any other required target modifications).",
5381 (decl_mangling_context,
5382 "Return target-specific mangling context of @var{decl} or @code{NULL_TREE}.",
5383 tree, (const_tree decl),
5384 hook_tree_const_tree_null)
5386 HOOK_VECTOR_END (cxx)
5388 /* Functions and data for emulated TLS support. */
5390 #define HOOK_PREFIX "TARGET_EMUTLS_"
5391 HOOK_VECTOR (TARGET_EMUTLS, emutls)
5393 /* Name of the address and common functions. */
5396 "Contains the name of the helper function that uses a TLS control\n\
5397 object to locate a TLS instance. The default causes libgcc's\n\
5398 emulated TLS helper function to be used.",
5399 const char *, "__builtin___emutls_get_address")
5403 "Contains the name of the helper function that should be used at\n\
5404 program startup to register TLS objects that are implicitly\n\
5405 initialized to zero. If this is @code{NULL}, all TLS objects will\n\
5406 have explicit initializers. The default causes libgcc's emulated TLS\n\
5407 registration function to be used.",
5408 const char *, "__builtin___emutls_register_common")
5410 /* Prefixes for proxy variable and template. */
5413 "Contains the name of the section in which TLS control variables should\n\
5414 be placed. The default of @code{NULL} allows these to be placed in\n\
5420 "Contains the name of the section in which TLS initializers should be\n\
5421 placed. The default of @code{NULL} allows these to be placed in any\n\
5425 /* Prefixes for proxy variable and template. */
5428 "Contains the prefix to be prepended to TLS control variable names.\n\
5429 The default of @code{NULL} uses a target-specific prefix.",
5434 "Contains the prefix to be prepended to TLS initializer objects. The\n\
5435 default of @code{NULL} uses a target-specific prefix.",
5438 /* Function to generate field definitions of the proxy variable. */
5441 "Specifies a function that generates the FIELD_DECLs for a TLS control\n\
5442 object type. @var{type} is the RECORD_TYPE the fields are for and\n\
5443 @var{name} should be filled with the structure tag, if the default of\n\
5444 @code{__emutls_object} is unsuitable. The default creates a type suitable\n\
5445 for libgcc's emulated TLS function.",
5446 tree, (tree type, tree *name),
5447 default_emutls_var_fields)
5449 /* Function to initialize a proxy variable. */
5452 "Specifies a function that generates the CONSTRUCTOR to initialize a\n\
5453 TLS control object. @var{var} is the TLS control object, @var{decl}\n\
5454 is the TLS object and @var{tmpl_addr} is the address of the\n\
5455 initializer. The default initializes libgcc's emulated TLS control object.",
5456 tree, (tree var, tree decl, tree tmpl_addr),
5457 default_emutls_var_init)
5459 /* Whether we are allowed to alter the usual alignment of the
5463 "Specifies whether the alignment of TLS control variable objects is\n\
5464 fixed and should not be increased as some backends may do to optimize\n\
5465 single objects. The default is false.",
5468 /* Whether we can emit debug information for TLS vars. */
5470 (debug_form_tls_address,
5471 "Specifies whether a DWARF @code{DW_OP_form_tls_address} location descriptor\n\
5472 may be used to describe emulated TLS control objects.",
5475 HOOK_VECTOR_END (emutls)
5478 #define HOOK_PREFIX "TARGET_OPTION_"
5479 HOOK_VECTOR (TARGET_OPTION_HOOKS, target_option_hooks)
5481 /* Function to validate the attribute((target(...))) strings. If
5482 the option is validated, the hook should also fill in
5483 DECL_FUNCTION_SPECIFIC_TARGET in the function decl node. */
5486 "This hook is called to parse @code{attribute(target(\"...\"))}, which\n\
5487 allows setting target-specific options on individual functions.\n\
5488 These function-specific options may differ\n\
5489 from the options specified on the command line. The hook should return\n\
5490 @code{true} if the options are valid.\n\
5492 The hook should set the @code{DECL_FUNCTION_SPECIFIC_TARGET} field in\n\
5493 the function declaration to hold a pointer to a target-specific\n\
5494 @code{struct cl_target_option} structure.",
5495 bool, (tree fndecl, tree name, tree args, int flags),
5496 default_target_option_valid_attribute_p)
5498 /* Function to save any extra target state in the target options structure. */
5501 "This hook is called to save any additional target-specific information\n\
5502 in the @code{struct cl_target_option} structure for function-specific\n\
5503 options from the @code{struct gcc_options} structure.\n\
5504 @xref{Option file format}.",
5505 void, (struct cl_target_option *ptr, struct gcc_options *opts), NULL)
5507 /* Function to restore any extra target state from the target options
5511 "This hook is called to restore any additional target-specific\n\
5512 information in the @code{struct cl_target_option} structure for\n\
5513 function-specific options to the @code{struct gcc_options} structure.",
5514 void, (struct gcc_options *opts, struct cl_target_option *ptr), NULL)
5516 /* Function to update target-specific option information after being
5520 "This hook is called to update target-specific information in the\n\
5521 @code{struct cl_target_option} structure after it is streamed in from\n\
5523 void, (struct cl_target_option *ptr), NULL)
5525 /* Function to print any extra target state from the target options
5529 "This hook is called to print any additional target-specific\n\
5530 information in the @code{struct cl_target_option} structure for\n\
5531 function-specific options.",
5532 void, (FILE *file, int indent, struct cl_target_option *ptr), NULL)
5534 /* Function to parse arguments to be validated for #pragma target, and to
5535 change the state if the options are valid. If the first argument is
5536 NULL, the second argument specifies the default options to use. Return
5537 true if the options are valid, and set the current state. */
5540 "This target hook parses the options for @code{#pragma GCC target}, which\n\
5541 sets the target-specific options for functions that occur later in the\n\
5542 input stream. The options accepted should be the same as those handled by the\n\
5543 @code{TARGET_OPTION_VALID_ATTRIBUTE_P} hook.",
5544 bool, (tree args, tree pop_target),
5545 default_target_option_pragma_parse)
5547 /* Do option overrides for the target. */
5550 "Sometimes certain combinations of command options do not make sense on\n\
5551 a particular target machine. You can override the hook\n\
5552 @code{TARGET_OPTION_OVERRIDE} to take account of this. This hooks is called\n\
5553 once just after all the command options have been parsed.\n\
5555 Don't use this hook to turn on various extra optimizations for\n\
5556 @option{-O}. That is what @code{TARGET_OPTION_OPTIMIZATION} is for.\n\
5558 If you need to do something whenever the optimization level is\n\
5559 changed via the optimize attribute or pragma, see\n\
5560 @code{TARGET_OVERRIDE_OPTIONS_AFTER_CHANGE}",
5564 /* This function returns true if DECL1 and DECL2 are versions of the same
5565 function. DECL1 and DECL2 are function versions if and only if they
5566 have the same function signature and different target specific attributes,
5567 that is, they are compiled for different target machines. */
5570 "This target hook returns @code{true} if @var{DECL1} and @var{DECL2} are\n\
5571 versions of the same function. @var{DECL1} and @var{DECL2} are function\n\
5572 versions if and only if they have the same function signature and\n\
5573 different target specific attributes, that is, they are compiled for\n\
5574 different target machines.",
5575 bool, (tree decl1, tree decl2),
5576 hook_bool_tree_tree_false)
5578 /* Function to determine if one function can inline another function. */
5580 #define HOOK_PREFIX "TARGET_"
5583 "This target hook returns @code{false} if the @var{caller} function\n\
5584 cannot inline @var{callee}, based on target specific information. By\n\
5585 default, inlining is not allowed if the callee function has function\n\
5586 specific target options and the caller does not use the same options.",
5587 bool, (tree caller, tree callee),
5588 default_target_can_inline_p)
5590 HOOK_VECTOR_END (target_option)
5592 /* For targets that need to mark extra registers as live on entry to
5593 the function, they should define this target hook and set their
5594 bits in the bitmap passed in. */
5596 (extra_live_on_entry,
5597 "Add any hard registers to @var{regs} that are live on entry to the\n\
5598 function. This hook only needs to be defined to provide registers that\n\
5599 cannot be found by examination of FUNCTION_ARG_REGNO_P, the callee saved\n\
5600 registers, STATIC_CHAIN_INCOMING_REGNUM, STATIC_CHAIN_REGNUM,\n\
5601 TARGET_STRUCT_VALUE_RTX, FRAME_POINTER_REGNUM, EH_USES,\n\
5602 FRAME_POINTER_REGNUM, ARG_POINTER_REGNUM, and the PIC_OFFSET_TABLE_REGNUM.",
5603 void, (bitmap regs),
5606 /* Targets should define this target hook to mark that non-callee clobbers are
5607 present in CALL_INSN_FUNCTION_USAGE for all the calls that bind to a local
5610 (call_fusage_contains_non_callee_clobbers,
5611 "Set to true if each call that binds to a local definition explicitly\n\
5612 clobbers or sets all non-fixed registers modified by performing the call.\n\
5613 That is, by the call pattern itself, or by code that might be inserted by the\n\
5614 linker (e.g. stubs, veneers, branch islands), but not including those\n\
5615 modifiable by the callee. The affected registers may be mentioned explicitly\n\
5616 in the call pattern, or included as clobbers in CALL_INSN_FUNCTION_USAGE.\n\
5617 The default version of this hook is set to false. The purpose of this hook\n\
5618 is to enable the fipa-ra optimization.",
5622 /* Fill in additional registers set up by prologue into a regset. */
5624 (set_up_by_prologue,
5625 "This hook should add additional registers that are computed by the prologue\
5626 to the hard regset for shrink-wrapping optimization purposes.",
5627 void, (struct hard_reg_set_container *),
5630 /* For targets that have attributes that can affect whether a
5631 function's return statements need checking. For instance a 'naked'
5632 function attribute. */
5635 "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.",
5637 hook_bool_tree_true)
5639 /* Determine the type of unwind info to emit for debugging. */
5642 "This hook defines the mechanism that will be used for describing frame\n\
5643 unwind information to the debugger. Normally the hook will return\n\
5644 @code{UI_DWARF2} if DWARF 2 debug information is enabled, and\n\
5645 return @code{UI_NONE} otherwise.\n\
5647 A target may return @code{UI_DWARF2} even when DWARF 2 debug information\n\
5648 is disabled in order to always output DWARF 2 frame information.\n\
5650 A target may return @code{UI_TARGET} if it has ABI specified unwind tables.\n\
5651 This will suppress generation of the normal debug frame unwind information.",
5652 enum unwind_info_type, (void),
5653 default_debug_unwind_info)
5655 /* The code parameter should be of type enum rtx_code but this is not
5656 defined at this time. */
5658 (canonicalize_comparison,
5659 "On some machines not all possible comparisons are defined, but you can\n\
5660 convert an invalid comparison into a valid one. For example, the Alpha\n\
5661 does not have a @code{GT} comparison, but you can use an @code{LT}\n\
5662 comparison instead and swap the order of the operands.\n\
5664 On such machines, implement this hook to do any required conversions.\n\
5665 @var{code} is the initial comparison code and @var{op0} and @var{op1}\n\
5666 are the left and right operands of the comparison, respectively. If\n\
5667 @var{op0_preserve_value} is @code{true} the implementation is not\n\
5668 allowed to change the value of @var{op0} since the value might be used\n\
5669 in RTXs which aren't comparisons. E.g. the implementation is not\n\
5670 allowed to swap operands in that case.\n\
5672 GCC will not assume that the comparison resulting from this macro is\n\
5673 valid but will see if the resulting insn matches a pattern in the\n\
5676 You need not to implement this hook if it would never change the\n\
5677 comparison code or operands.",
5678 void, (int *code, rtx *op0, rtx *op1, bool op0_preserve_value),
5679 default_canonicalize_comparison)
5682 (atomic_test_and_set_trueval,
5683 "This value should be set if the result written by\
5684 @code{atomic_test_and_set} is not exactly 1, i.e. the\
5685 @code{bool} @code{true}.",
5688 /* Return an unsigned int representing the alignment (in bits) of the atomic
5689 type which maps to machine MODE. This allows alignment to be overridden
5692 (atomic_align_for_mode,
5693 "If defined, this function returns an appropriate alignment in bits for an\
5694 atomic object of machine_mode @var{mode}. If 0 is returned then the\
5695 default alignment for the specified mode is used. ",
5696 unsigned int, (machine_mode mode),
5700 (atomic_assign_expand_fenv,
5701 "ISO C11 requires atomic compound assignments that may raise floating-point\
5702 exceptions to raise exceptions corresponding to the arithmetic operation\
5703 whose result was successfully stored in a compare-and-exchange sequence. \
5704 This requires code equivalent to calls to @code{feholdexcept},\
5705 @code{feclearexcept} and @code{feupdateenv} to be generated at\
5706 appropriate points in the compare-and-exchange sequence. This hook should\
5707 set @code{*@var{hold}} to an expression equivalent to the call to\
5708 @code{feholdexcept}, @code{*@var{clear}} to an expression equivalent to\
5709 the call to @code{feclearexcept} and @code{*@var{update}} to an expression\
5710 equivalent to the call to @code{feupdateenv}. The three expressions are\
5711 @code{NULL_TREE} on entry to the hook and may be left as @code{NULL_TREE}\
5712 if no code is required in a particular place. The default implementation\
5713 leaves all three expressions as @code{NULL_TREE}. The\
5714 @code{__atomic_feraiseexcept} function from @code{libatomic} may be of use\
5715 as part of the code generated in @code{*@var{update}}.",
5716 void, (tree *hold, tree *clear, tree *update),
5717 default_atomic_assign_expand_fenv)
5719 /* Leave the boolean fields at the end. */
5721 /* True if we can create zeroed data by switching to a BSS section
5722 and then using ASM_OUTPUT_SKIP to allocate the space. */
5724 (have_switchable_bss_sections,
5725 "This flag is true if we can create zeroed data by switching to a BSS\n\
5726 section and then using @code{ASM_OUTPUT_SKIP} to allocate the space.\n\
5727 This is true on most ELF targets.",
5730 /* True if "native" constructors and destructors are supported,
5731 false if we're using collect2 for the job. */
5734 "This value is true if the target supports some ``native'' method of\n\
5735 collecting constructors and destructors to be run at startup and exit.\n\
5736 It is false if we must use @command{collect2}.",
5739 /* True if thread-local storage is supported. */
5742 "Contains the value true if the target supports thread-local storage.\n\
5743 The default value is false.",
5746 /* True if a small readonly data section is supported. */
5748 (have_srodata_section,
5749 "Contains the value true if the target places read-only\n\
5750 ``small data'' into a separate section. The default value is false.",
5753 /* True if EH frame info sections should be zero-terminated. */
5755 (terminate_dw2_eh_frame_info,
5756 "Contains the value true if the target should add a zero word onto the\n\
5757 end of a Dwarf-2 frame info section when used for exception handling.\n\
5758 Default value is false if @code{EH_FRAME_SECTION_NAME} is defined, and\n\
5762 /* True if #NO_APP should be emitted at the beginning of assembly output. */
5764 (asm_file_start_app_off,
5765 "If this flag is true, the text of the macro @code{ASM_APP_OFF} will be\n\
5766 printed as the very first line in the assembly file, unless\n\
5767 @option{-fverbose-asm} is in effect. (If that macro has been defined\n\
5768 to the empty string, this variable has no effect.) With the normal\n\
5769 definition of @code{ASM_APP_OFF}, the effect is to notify the GNU\n\
5770 assembler that it need not bother stripping comments or extra\n\
5771 whitespace from its input. This allows it to work a bit faster.\n\
5773 The default is false. You should not set it to true unless you have\n\
5774 verified that your port does not generate any extra whitespace or\n\
5775 comments that will cause GAS to issue errors in NO_APP mode.",
5778 /* True if output_file_directive should be called for main_input_filename
5779 at the beginning of assembly output. */
5781 (asm_file_start_file_directive,
5782 "If this flag is true, @code{output_file_directive} will be called\n\
5783 for the primary source file, immediately after printing\n\
5784 @code{ASM_APP_OFF} (if that is enabled). Most ELF assemblers expect\n\
5785 this to be done. The default is false.",
5788 /* Returns true if we should generate exception tables for use with the
5789 ARM EABI. The effects the encoding of function exception specifications. */
5792 "This flag should be set to @code{true} on targets that use an ARM EABI\n\
5793 based unwinding library, and @code{false} on other targets. This effects\n\
5794 the format of unwinding tables, and how the unwinder in entered after\n\
5795 running a cleanup. The default is @code{false}.",
5799 (want_debug_pub_sections,
5800 "True if the @code{.debug_pubtypes} and @code{.debug_pubnames} sections\
5801 should be emitted. These sections are not used on most platforms, and\
5802 in particular GDB does not use them.",
5807 "True if the @code{DW_AT_comp_dir} attribute should be emitted for each \
5808 compilation unit. This attribute is required for the darwin linker \
5809 to emit debug information.",
5813 (delay_sched2, "True if sched2 is not to be run at its normal place.\n\
5814 This usually means it will be run as part of machine-specific reorg.",
5818 (delay_vartrack, "True if vartrack is not to be run at its normal place.\n\
5819 This usually means it will be run as part of machine-specific reorg.",
5823 (no_register_allocation, "True if register allocation and the passes\n\
5824 following it should not be run. Usually true only for virtual assembler\n\
5828 /* Leave the boolean fields at the end. */
5830 /* Functions related to mode switching. */
5832 #define HOOK_PREFIX "TARGET_MODE_"
5833 HOOK_VECTOR (TARGET_TOGGLE_, mode_switching)
5837 "Generate one or more insns to set @var{entity} to @var{mode}. @var{hard_reg_live} is the set of hard registers live at the point where the insn(s) are to be inserted. @var{prev_moxde} indicates the mode to switch from. Sets of a lower numbered entity will be emitted before sets of a higher numbered entity to a mode of the same or lower priority.",
5838 void, (int entity, int mode, int prev_mode, HARD_REG_SET regs_live), NULL)
5842 "@var{entity} is an integer specifying a mode-switched entity. If @code{OPTIMIZE_MODE_SWITCHING} is defined, you must define this macro to return an integer value not larger than the corresponding element in @code{NUM_MODES_FOR_MODE_SWITCHING}, to denote the mode that @var{entity} must be switched into prior to the execution of @var{insn}.",
5843 int, (int entity, rtx_insn *insn), NULL)
5847 "@var{entity} is an integer specifying a mode-switched entity. If this macro is defined, it is evaluated for every @var{insn} during mode switching. It determines the mode that an insn results in (if different from the incoming mode).",
5848 int, (int entity, int mode, rtx_insn *insn), NULL)
5852 "If this macro is defined, it is evaluated for every @var{entity} that needs mode switching. It should evaluate to an integer, which is a mode that @var{entity} is assumed to be switched to at function entry. If @code{TARGET_MODE_ENTRY} is defined then @code{TARGET_MODE_EXIT} must be defined.",
5853 int, (int entity), NULL)
5857 "If this macro is defined, it is evaluated for every @var{entity} that needs mode switching. It should evaluate to an integer, which is a mode that @var{entity} is assumed to be switched to at function exit. If @code{TARGET_MODE_EXIT} is defined then @code{TARGET_MODE_ENTRY} must be defined.",
5858 int, (int entity), NULL)
5862 "This macro specifies the order in which modes for @var{entity} are processed. 0 is the highest priority, @code{NUM_MODES_FOR_MODE_SWITCHING[@var{entity}] - 1} the lowest. The value of the macro should be an integer designating a mode for @var{entity}. For any fixed @var{entity}, @code{mode_priority} (@var{entity}, @var{n}) shall be a bijection in 0 @dots{} @code{num_modes_for_mode_switching[@var{entity}] - 1}.",
5863 int, (int entity, int n), NULL)
5865 HOOK_VECTOR_END (mode_switching)
5867 /* Close the 'struct gcc_target' definition. */
5868 HOOK_VECTOR_END (C90_EMPTY_HACK)