2007-03-05 Matthias Klose <doko@debian.org>
[official-gcc.git] / gcc / function.h
blobe02077f6c63c36c76f8ea1acd703e3d6a3c8a54d
1 /* Structure for saving state for a nested function.
2 Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000, 2003, 2004, 2005 Free Software Foundation, Inc.
5 This file is part of GCC.
7 GCC is free software; you can redistribute it and/or modify it under
8 the terms of the GNU General Public License as published by the Free
9 Software Foundation; either version 2, or (at your option) any later
10 version.
12 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 for more details.
17 You should have received a copy of the GNU General Public License
18 along with GCC; see the file COPYING. If not, write to the Free
19 Software Foundation, 51 Franklin Street, Fifth Floor, Boston, MA
20 02110-1301, USA. */
22 #ifndef GCC_FUNCTION_H
23 #define GCC_FUNCTION_H
25 #include "tree.h"
26 #include "hashtab.h"
28 struct var_refs_queue GTY(())
30 rtx modified;
31 enum machine_mode promoted_mode;
32 int unsignedp;
33 struct var_refs_queue *next;
36 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
37 Each element describes one pending sequence.
38 The main insn-chain is saved in the last element of the chain,
39 unless the chain is empty. */
41 struct sequence_stack GTY(())
43 /* First and last insns in the chain of the saved sequence. */
44 rtx first;
45 rtx last;
46 struct sequence_stack *next;
49 extern struct sequence_stack *sequence_stack;
51 /* Stack of single obstacks. */
53 struct simple_obstack_stack
55 struct obstack *obstack;
56 struct simple_obstack_stack *next;
59 struct emit_status GTY(())
61 /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
62 After rtl generation, it is 1 plus the largest register number used. */
63 int x_reg_rtx_no;
65 /* Lowest label number in current function. */
66 int x_first_label_num;
68 /* The ends of the doubly-linked chain of rtl for the current function.
69 Both are reset to null at the start of rtl generation for the function.
71 start_sequence saves both of these on `sequence_stack' and then starts
72 a new, nested sequence of insns. */
73 rtx x_first_insn;
74 rtx x_last_insn;
76 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
77 Each element describes one pending sequence.
78 The main insn-chain is saved in the last element of the chain,
79 unless the chain is empty. */
80 struct sequence_stack *sequence_stack;
82 /* INSN_UID for next insn emitted.
83 Reset to 1 for each function compiled. */
84 int x_cur_insn_uid;
86 /* Location the last line-number NOTE emitted.
87 This is used to avoid generating duplicates. */
88 location_t x_last_location;
90 /* The length of the regno_pointer_align, regno_decl, and x_regno_reg_rtx
91 vectors. Since these vectors are needed during the expansion phase when
92 the total number of registers in the function is not yet known, the
93 vectors are copied and made bigger when necessary. */
94 int regno_pointer_align_length;
96 /* Indexed by pseudo register number, if nonzero gives the known alignment
97 for that pseudo (if REG_POINTER is set in x_regno_reg_rtx).
98 Allocated in parallel with x_regno_reg_rtx. */
99 unsigned char * GTY ((length ("%h.x_reg_rtx_no")))
100 regno_pointer_align;
102 /* Indexed by pseudo register number, gives the rtx for that pseudo.
103 Allocated in parallel with regno_pointer_align. */
104 rtx * GTY ((length ("%h.x_reg_rtx_no"))) x_regno_reg_rtx;
107 /* For backward compatibility... eventually these should all go away. */
108 #define reg_rtx_no (cfun->emit->x_reg_rtx_no)
109 #define regno_reg_rtx (cfun->emit->x_regno_reg_rtx)
110 #define seq_stack (cfun->emit->sequence_stack)
112 #define REGNO_POINTER_ALIGN(REGNO) (cfun->emit->regno_pointer_align[REGNO])
114 struct expr_status GTY(())
116 /* Number of units that we should eventually pop off the stack.
117 These are the arguments to function calls that have already returned. */
118 int x_pending_stack_adjust;
120 /* Under some ABIs, it is the caller's responsibility to pop arguments
121 pushed for function calls. A naive implementation would simply pop
122 the arguments immediately after each call. However, if several
123 function calls are made in a row, it is typically cheaper to pop
124 all the arguments after all of the calls are complete since a
125 single pop instruction can be used. Therefore, GCC attempts to
126 defer popping the arguments until absolutely necessary. (For
127 example, at the end of a conditional, the arguments must be popped,
128 since code outside the conditional won't know whether or not the
129 arguments need to be popped.)
131 When INHIBIT_DEFER_POP is nonzero, however, the compiler does not
132 attempt to defer pops. Instead, the stack is popped immediately
133 after each call. Rather then setting this variable directly, use
134 NO_DEFER_POP and OK_DEFER_POP. */
135 int x_inhibit_defer_pop;
137 /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack
138 boundary can be momentarily unaligned while pushing the arguments.
139 Record the delta since last aligned boundary here in order to get
140 stack alignment in the nested function calls working right. */
141 int x_stack_pointer_delta;
143 /* Nonzero means __builtin_saveregs has already been done in this function.
144 The value is the pseudoreg containing the value __builtin_saveregs
145 returned. */
146 rtx x_saveregs_value;
148 /* Similarly for __builtin_apply_args. */
149 rtx x_apply_args_value;
151 /* List of labels that must never be deleted. */
152 rtx x_forced_labels;
155 #define pending_stack_adjust (cfun->expr->x_pending_stack_adjust)
156 #define inhibit_defer_pop (cfun->expr->x_inhibit_defer_pop)
157 #define saveregs_value (cfun->expr->x_saveregs_value)
158 #define apply_args_value (cfun->expr->x_apply_args_value)
159 #define forced_labels (cfun->expr->x_forced_labels)
160 #define stack_pointer_delta (cfun->expr->x_stack_pointer_delta)
162 struct gimple_df;
163 struct temp_slot;
164 typedef struct temp_slot *temp_slot_p;
166 DEF_VEC_P(temp_slot_p);
167 DEF_VEC_ALLOC_P(temp_slot_p,gc);
169 enum function_frequency {
170 /* This function most likely won't be executed at all.
171 (set only when profile feedback is available). */
172 FUNCTION_FREQUENCY_UNLIKELY_EXECUTED,
173 /* The default value. */
174 FUNCTION_FREQUENCY_NORMAL,
175 /* Optimize this function hard
176 (set only when profile feedback is available). */
177 FUNCTION_FREQUENCY_HOT
180 /* This structure can save all the important global and static variables
181 describing the status of the current function. */
183 struct function GTY(())
185 struct eh_status *eh;
186 struct expr_status *expr;
187 struct emit_status *emit;
188 struct varasm_status *varasm;
190 /* The control flow graph for this function. */
191 struct control_flow_graph *cfg;
192 /* SSA and dataflow information. */
193 struct gimple_df *gimple_df;
195 /* The loops in this function. */
196 struct loops * GTY((skip)) x_current_loops;
198 /* Value histograms attached to particular statements. */
199 htab_t GTY((skip)) value_histograms;
201 /* For function.c. */
203 /* Points to the FUNCTION_DECL of this function. */
204 tree decl;
206 /* Function containing this function, if any. */
207 struct function *outer;
209 /* Number of bytes of args popped by function being compiled on its return.
210 Zero if no bytes are to be popped.
211 May affect compilation of return insn or of function epilogue. */
212 int pops_args;
214 /* If function's args have a fixed size, this is that size, in bytes.
215 Otherwise, it is -1.
216 May affect compilation of return insn or of function epilogue. */
217 int args_size;
219 /* # bytes the prologue should push and pretend that the caller pushed them.
220 The prologue must do this, but only if parms can be passed in
221 registers. */
222 int pretend_args_size;
224 /* # of bytes of outgoing arguments. If ACCUMULATE_OUTGOING_ARGS is
225 defined, the needed space is pushed by the prologue. */
226 int outgoing_args_size;
228 /* This is the offset from the arg pointer to the place where the first
229 anonymous arg can be found, if there is one. */
230 rtx arg_offset_rtx;
232 /* Quantities of various kinds of registers
233 used for the current function's args. */
234 CUMULATIVE_ARGS args_info;
236 /* If nonzero, an RTL expression for the location at which the current
237 function returns its result. If the current function returns its
238 result in a register, current_function_return_rtx will always be
239 the hard register containing the result. */
240 rtx return_rtx;
242 /* The arg pointer hard register, or the pseudo into which it was copied. */
243 rtx internal_arg_pointer;
245 /* Opaque pointer used by get_hard_reg_initial_val and
246 has_hard_reg_initial_val (see integrate.[hc]). */
247 struct initial_value_struct *hard_reg_initial_vals;
249 /* List (chain of EXPR_LIST) of labels heading the current handlers for
250 nonlocal gotos. */
251 rtx x_nonlocal_goto_handler_labels;
253 /* Label that will go on function epilogue.
254 Jumping to this label serves as a "return" instruction
255 on machines which require execution of the epilogue on all returns. */
256 rtx x_return_label;
258 /* Label that will go on the end of function epilogue.
259 Jumping to this label serves as a "naked return" instruction
260 on machines which require execution of the epilogue on all returns. */
261 rtx x_naked_return_label;
263 /* List (chain of EXPR_LISTs) of all stack slots in this function.
264 Made for the sake of unshare_all_rtl. */
265 rtx x_stack_slot_list;
267 /* Place after which to insert the tail_recursion_label if we need one. */
268 rtx x_stack_check_probe_note;
270 /* Location at which to save the argument pointer if it will need to be
271 referenced. There are two cases where this is done: if nonlocal gotos
272 exist, or if vars stored at an offset from the argument pointer will be
273 needed by inner routines. */
274 rtx x_arg_pointer_save_area;
276 /* Offset to end of allocated area of stack frame.
277 If stack grows down, this is the address of the last stack slot allocated.
278 If stack grows up, this is the address for the next slot. */
279 HOST_WIDE_INT x_frame_offset;
281 /* A PARM_DECL that should contain the static chain for this function.
282 It will be initialized at the beginning of the function. */
283 tree static_chain_decl;
285 /* An expression that contains the non-local goto save area. The first
286 word is the saved frame pointer and the second is the saved stack
287 pointer. */
288 tree nonlocal_goto_save_area;
290 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */
291 rtx x_parm_birth_insn;
293 /* List of all used temporaries allocated, by level. */
294 VEC(temp_slot_p,gc) *x_used_temp_slots;
296 /* List of available temp slots. */
297 struct temp_slot *x_avail_temp_slots;
299 /* This slot is initialized as 0 and is added to
300 during the nested function. */
301 struct var_refs_queue *fixup_var_refs_queue;
303 /* Current nesting level for temporaries. */
304 int x_temp_slot_level;
306 /* Highest label number in current function. */
307 int inl_max_label_num;
309 /* Function sequence number for profiling, debugging, etc. */
310 int funcdef_no;
312 /* For flow.c. */
314 /* Highest loop depth seen so far in loop analysis. Used in flow.c
315 for the "failure strategy" when doing liveness analysis starting
316 with non-empty initial sets. */
317 int max_loop_depth;
319 /* For md files. */
321 /* tm.h can use this to store whatever it likes. */
322 struct machine_function * GTY ((maybe_undef)) machine;
324 /* The largest alignment of slot allocated on the stack. */
325 unsigned int stack_alignment_needed;
327 /* Preferred alignment of the end of stack frame. */
328 unsigned int preferred_stack_boundary;
330 /* Language-specific code can use this to store whatever it likes. */
331 struct language_function * language;
333 /* Used types hash table. */
334 htab_t GTY ((param_is (union tree_node))) used_types_hash;
336 /* For reorg. */
338 /* If some insns can be deferred to the delay slots of the epilogue, the
339 delay list for them is recorded here. */
340 rtx epilogue_delay_list;
342 /* Maximal number of entities in the single jumptable. Used to estimate
343 final flowgraph size. */
344 int max_jumptable_ents;
346 /* UIDs for LABEL_DECLs. */
347 int last_label_uid;
349 /* Line number of the end of the function. */
350 location_t function_end_locus;
352 /* Array mapping insn uids to blocks. */
353 VEC(tree,gc) *ib_boundaries_block;
355 /* The variables unexpanded so far. */
356 tree unexpanded_var_list;
358 /* Assembly labels for the hot and cold text sections, to
359 be used by debugger functions for determining the size of text
360 sections. */
362 const char *hot_section_label;
363 const char *cold_section_label;
364 const char *hot_section_end_label;
365 const char *cold_section_end_label;
367 /* String to be used for name of cold text sections, via
368 targetm.asm_out.named_section. */
370 const char *unlikely_text_section_name;
372 /* A variable living at the top of the frame that holds a known value.
373 Used for detecting stack clobbers. */
374 tree stack_protect_guard;
376 /* Properties used by the pass manager. */
377 unsigned int curr_properties;
378 unsigned int last_verified;
380 /* Collected bit flags. */
382 /* Nonzero if function being compiled needs to be given an address
383 where the value should be stored. */
384 unsigned int returns_struct : 1;
386 /* Nonzero if function being compiled needs to
387 return the address of where it has put a structure value. */
388 unsigned int returns_pcc_struct : 1;
390 /* Nonzero if the current function returns a pointer type. */
391 unsigned int returns_pointer : 1;
393 /* Nonzero if function being compiled can call setjmp. */
394 unsigned int calls_setjmp : 1;
396 /* Nonzero if function being compiled can call alloca,
397 either as a subroutine or builtin. */
398 unsigned int calls_alloca : 1;
400 /* Nonzero if function being compiled called builtin_return_addr or
401 builtin_frame_address with nonzero count. */
402 unsigned int accesses_prior_frames : 1;
404 /* Nonzero if the function calls __builtin_eh_return. */
405 unsigned int calls_eh_return : 1;
407 /* Nonzero if function being compiled receives nonlocal gotos
408 from nested functions. */
409 unsigned int has_nonlocal_label : 1;
411 /* Nonzero if function being compiled has nonlocal gotos to parent
412 function. */
413 unsigned int has_nonlocal_goto : 1;
415 /* Nonzero if the current function is a thunk, i.e., a lightweight
416 function implemented by the output_mi_thunk hook) that just
417 adjusts one of its arguments and forwards to another
418 function. */
419 unsigned int is_thunk : 1;
421 /* This bit is used by the exception handling logic. It is set if all
422 calls (if any) are sibling calls. Such functions do not have to
423 have EH tables generated, as they cannot throw. A call to such a
424 function, however, should be treated as throwing if any of its callees
425 can throw. */
426 unsigned int all_throwers_are_sibcalls : 1;
428 /* Nonzero if profiling code should be generated. */
429 unsigned int profile : 1;
431 /* Nonzero if stack limit checking should be enabled in the current
432 function. */
433 unsigned int limit_stack : 1;
435 /* Nonzero if current function uses stdarg.h or equivalent. */
436 unsigned int stdarg : 1;
438 /* Nonzero if the back-end should not keep track of expressions that
439 determine the size of variable-sized objects. Normally, such
440 expressions are saved away, and then expanded when the next
441 function is started. For example, if a parameter has a
442 variable-sized type, then the size of the parameter is computed
443 when the function body is entered. However, some front-ends do
444 not desire this behavior. */
445 unsigned int x_dont_save_pending_sizes_p : 1;
447 /* Nonzero if the current function uses the constant pool. */
448 unsigned int uses_const_pool : 1;
450 /* Nonzero if the current function uses pic_offset_table_rtx. */
451 unsigned int uses_pic_offset_table : 1;
453 /* Nonzero if the current function needs an lsda for exception handling. */
454 unsigned int uses_eh_lsda : 1;
456 /* Nonzero if code to initialize arg_pointer_save_area has been emitted. */
457 unsigned int arg_pointer_save_area_init : 1;
459 unsigned int after_inlining : 1;
461 /* Set when the call to function itself has been emit. */
462 unsigned int recursive_call_emit : 1;
464 /* Set when the tail call has been produced. */
465 unsigned int tail_call_emit : 1;
467 /* How commonly executed the function is. Initialized during branch
468 probabilities pass. */
469 ENUM_BITFIELD (function_frequency) function_frequency : 2;
471 /* Number of units of general registers that need saving in stdarg
472 function. What unit is depends on the backend, either it is number
473 of bytes, or it can be number of registers. */
474 unsigned int va_list_gpr_size : 8;
476 /* Number of units of floating point registers that need saving in stdarg
477 function. */
478 unsigned int va_list_fpr_size : 8;
480 /* FIXME tuples: This bit is temporarily here to mark when a
481 function has been gimplified, so we can make sure we're not
482 creating non GIMPLE tuples after gimplification. */
483 unsigned gimplified : 1;
486 /* If va_list_[gf]pr_size is set to this, it means we don't know how
487 many units need to be saved. */
488 #define VA_LIST_MAX_GPR_SIZE 255
489 #define VA_LIST_MAX_FPR_SIZE 255
491 /* The function currently being compiled. */
492 extern GTY(()) struct function *cfun;
494 /* Pointer to chain of `struct function' for containing functions. */
495 extern GTY(()) struct function *outer_function_chain;
497 /* Nonzero if we've already converted virtual regs to hard regs. */
498 extern int virtuals_instantiated;
500 /* Nonzero if at least one trampoline has been created. */
501 extern int trampolines_created;
503 /* For backward compatibility... eventually these should all go away. */
504 #define current_function_pops_args (cfun->pops_args)
505 #define current_function_returns_struct (cfun->returns_struct)
506 #define current_function_returns_pcc_struct (cfun->returns_pcc_struct)
507 #define current_function_returns_pointer (cfun->returns_pointer)
508 #define current_function_calls_setjmp (cfun->calls_setjmp)
509 #define current_function_calls_alloca (cfun->calls_alloca)
510 #define current_function_accesses_prior_frames (cfun->accesses_prior_frames)
511 #define current_function_calls_eh_return (cfun->calls_eh_return)
512 #define current_function_is_thunk (cfun->is_thunk)
513 #define current_function_args_info (cfun->args_info)
514 #define current_function_args_size (cfun->args_size)
515 #define current_function_pretend_args_size (cfun->pretend_args_size)
516 #define current_function_outgoing_args_size (cfun->outgoing_args_size)
517 #define current_function_arg_offset_rtx (cfun->arg_offset_rtx)
518 #define current_function_stdarg (cfun->stdarg)
519 #define current_function_internal_arg_pointer (cfun->internal_arg_pointer)
520 #define current_function_return_rtx (cfun->return_rtx)
521 #define current_function_profile (cfun->profile)
522 #define current_function_funcdef_no (cfun->funcdef_no)
523 #define current_function_limit_stack (cfun->limit_stack)
524 #define current_function_uses_pic_offset_table (cfun->uses_pic_offset_table)
525 #define current_function_uses_const_pool (cfun->uses_const_pool)
526 #define current_function_epilogue_delay_list (cfun->epilogue_delay_list)
527 #define current_function_has_nonlocal_label (cfun->has_nonlocal_label)
528 #define current_function_has_nonlocal_goto (cfun->has_nonlocal_goto)
530 #define return_label (cfun->x_return_label)
531 #define naked_return_label (cfun->x_naked_return_label)
532 #define stack_slot_list (cfun->x_stack_slot_list)
533 #define parm_birth_insn (cfun->x_parm_birth_insn)
534 #define frame_offset (cfun->x_frame_offset)
535 #define stack_check_probe_note (cfun->x_stack_check_probe_note)
536 #define arg_pointer_save_area (cfun->x_arg_pointer_save_area)
537 #define used_temp_slots (cfun->x_used_temp_slots)
538 #define avail_temp_slots (cfun->x_avail_temp_slots)
539 #define temp_slot_level (cfun->x_temp_slot_level)
540 #define nonlocal_goto_handler_labels (cfun->x_nonlocal_goto_handler_labels)
541 #define current_loops (cfun->x_current_loops)
542 #define VALUE_HISTOGRAMS(fun) (fun)->value_histograms
544 /* Given a function decl for a containing function,
545 return the `struct function' for it. */
546 struct function *find_function_data (tree);
548 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
549 and create duplicate blocks. */
550 extern void reorder_blocks (void);
552 /* Set BLOCK_NUMBER for all the blocks in FN. */
553 extern void number_blocks (tree);
555 extern void clear_block_marks (tree);
556 extern tree blocks_nreverse (tree);
557 extern void reset_block_changes (void);
558 extern void record_block_change (tree);
559 extern void finalize_block_changes (void);
560 extern void check_block_change (rtx, tree *);
561 extern void free_block_changes (void);
563 /* Return size needed for stack frame based on slots so far allocated.
564 This size counts from zero. It is not rounded to STACK_BOUNDARY;
565 the caller may have to do that. */
566 extern HOST_WIDE_INT get_frame_size (void);
568 /* Issue an error message and return TRUE if frame OFFSET overflows in
569 the signed target pointer arithmetics for function FUNC. Otherwise
570 return FALSE. */
571 extern bool frame_offset_overflow (HOST_WIDE_INT, tree);
573 /* A pointer to a function to create target specific, per-function
574 data structures. */
575 extern struct machine_function * (*init_machine_status) (void);
577 /* Save and restore status information for a nested function. */
578 extern void free_after_parsing (struct function *);
579 extern void free_after_compilation (struct function *);
581 extern void init_varasm_status (struct function *);
583 #ifdef RTX_CODE
584 extern void diddle_return_value (void (*)(rtx, void*), void*);
585 extern void clobber_return_register (void);
586 #endif
588 extern rtx get_arg_pointer_save_area (struct function *);
590 /* Returns the name of the current function. */
591 extern const char *current_function_name (void);
593 extern void do_warn_unused_parameter (tree);
595 extern bool pass_by_reference (CUMULATIVE_ARGS *, enum machine_mode,
596 tree, bool);
597 extern bool reference_callee_copied (CUMULATIVE_ARGS *, enum machine_mode,
598 tree, bool);
600 extern void used_types_insert (tree);
602 extern int get_next_funcdef_no (void);
603 #endif /* GCC_FUNCTION_H */