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
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
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
22 #ifndef GCC_FUNCTION_H
23 #define GCC_FUNCTION_H
28 struct var_refs_queue GTY(())
31 enum machine_mode promoted_mode;
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. */
46 struct sequence_stack *next;
49 /* Stack of single obstacks. */
51 struct simple_obstack_stack
53 struct obstack *obstack;
54 struct simple_obstack_stack *next;
57 struct emit_status GTY(())
59 /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
60 After rtl generation, it is 1 plus the largest register number used. */
63 /* Lowest label number in current function. */
64 int x_first_label_num;
66 /* The ends of the doubly-linked chain of rtl for the current function.
67 Both are reset to null at the start of rtl generation for the function.
69 start_sequence saves both of these on `sequence_stack' and then starts
70 a new, nested sequence of insns. */
74 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
75 Each element describes one pending sequence.
76 The main insn-chain is saved in the last element of the chain,
77 unless the chain is empty. */
78 struct sequence_stack *sequence_stack;
80 /* INSN_UID for next insn emitted.
81 Reset to 1 for each function compiled. */
84 /* Location the last line-number NOTE emitted.
85 This is used to avoid generating duplicates. */
86 location_t x_last_location;
88 /* The length of the regno_pointer_align, regno_decl, and x_regno_reg_rtx
89 vectors. Since these vectors are needed during the expansion phase when
90 the total number of registers in the function is not yet known, the
91 vectors are copied and made bigger when necessary. */
92 int regno_pointer_align_length;
94 /* Indexed by pseudo register number, if nonzero gives the known alignment
95 for that pseudo (if REG_POINTER is set in x_regno_reg_rtx).
96 Allocated in parallel with x_regno_reg_rtx. */
97 unsigned char * GTY ((length ("%h.x_reg_rtx_no")))
100 /* Indexed by pseudo register number, gives the rtx for that pseudo.
101 Allocated in parallel with regno_pointer_align. */
102 rtx * GTY ((length ("%h.x_reg_rtx_no"))) x_regno_reg_rtx;
105 /* For backward compatibility... eventually these should all go away. */
106 #define reg_rtx_no (cfun->emit->x_reg_rtx_no)
107 #define regno_reg_rtx (cfun->emit->x_regno_reg_rtx)
108 #define seq_stack (cfun->emit->sequence_stack)
110 #define REGNO_POINTER_ALIGN(REGNO) (cfun->emit->regno_pointer_align[REGNO])
112 struct expr_status GTY(())
114 /* Number of units that we should eventually pop off the stack.
115 These are the arguments to function calls that have already returned. */
116 int x_pending_stack_adjust;
118 /* Under some ABIs, it is the caller's responsibility to pop arguments
119 pushed for function calls. A naive implementation would simply pop
120 the arguments immediately after each call. However, if several
121 function calls are made in a row, it is typically cheaper to pop
122 all the arguments after all of the calls are complete since a
123 single pop instruction can be used. Therefore, GCC attempts to
124 defer popping the arguments until absolutely necessary. (For
125 example, at the end of a conditional, the arguments must be popped,
126 since code outside the conditional won't know whether or not the
127 arguments need to be popped.)
129 When INHIBIT_DEFER_POP is nonzero, however, the compiler does not
130 attempt to defer pops. Instead, the stack is popped immediately
131 after each call. Rather then setting this variable directly, use
132 NO_DEFER_POP and OK_DEFER_POP. */
133 int x_inhibit_defer_pop;
135 /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack
136 boundary can be momentarily unaligned while pushing the arguments.
137 Record the delta since last aligned boundary here in order to get
138 stack alignment in the nested function calls working right. */
139 int x_stack_pointer_delta;
141 /* Nonzero means __builtin_saveregs has already been done in this function.
142 The value is the pseudoreg containing the value __builtin_saveregs
144 rtx x_saveregs_value;
146 /* Similarly for __builtin_apply_args. */
147 rtx x_apply_args_value;
149 /* List of labels that must never be deleted. */
153 #define pending_stack_adjust (cfun->expr->x_pending_stack_adjust)
154 #define inhibit_defer_pop (cfun->expr->x_inhibit_defer_pop)
155 #define saveregs_value (cfun->expr->x_saveregs_value)
156 #define apply_args_value (cfun->expr->x_apply_args_value)
157 #define forced_labels (cfun->expr->x_forced_labels)
158 #define stack_pointer_delta (cfun->expr->x_stack_pointer_delta)
162 typedef struct temp_slot *temp_slot_p;
164 DEF_VEC_P(temp_slot_p);
165 DEF_VEC_ALLOC_P(temp_slot_p,gc);
167 enum function_frequency {
168 /* This function most likely won't be executed at all.
169 (set only when profile feedback is available or via function attribute). */
170 FUNCTION_FREQUENCY_UNLIKELY_EXECUTED,
171 /* The default value. */
172 FUNCTION_FREQUENCY_NORMAL,
173 /* Optimize this function hard
174 (set only when profile feedback is available or via function attribute). */
175 FUNCTION_FREQUENCY_HOT
178 /* This structure can save all the important global and static variables
179 describing the status of the current function. */
181 struct function GTY(())
183 struct eh_status *eh;
184 struct expr_status *expr;
185 struct emit_status *emit;
186 struct varasm_status *varasm;
188 /* The control flow graph for this function. */
189 struct control_flow_graph *cfg;
190 /* SSA and dataflow information. */
191 struct gimple_df *gimple_df;
193 /* The loops in this function. */
194 struct loops * GTY((skip)) x_current_loops;
196 /* Value histograms attached to particular statements. */
197 htab_t GTY((skip)) value_histograms;
199 /* For function.c. */
201 /* Points to the FUNCTION_DECL of this function. */
204 /* Function containing this function, if any. */
205 struct function *outer;
207 /* Number of bytes of args popped by function being compiled on its return.
208 Zero if no bytes are to be popped.
209 May affect compilation of return insn or of function epilogue. */
212 /* If function's args have a fixed size, this is that size, in bytes.
214 May affect compilation of return insn or of function epilogue. */
217 /* # bytes the prologue should push and pretend that the caller pushed them.
218 The prologue must do this, but only if parms can be passed in
220 int pretend_args_size;
222 /* # of bytes of outgoing arguments. If ACCUMULATE_OUTGOING_ARGS is
223 defined, the needed space is pushed by the prologue. */
224 int outgoing_args_size;
226 /* This is the offset from the arg pointer to the place where the first
227 anonymous arg can be found, if there is one. */
230 /* Quantities of various kinds of registers
231 used for the current function's args. */
232 CUMULATIVE_ARGS args_info;
234 /* If nonzero, an RTL expression for the location at which the current
235 function returns its result. If the current function returns its
236 result in a register, current_function_return_rtx will always be
237 the hard register containing the result. */
240 /* The arg pointer hard register, or the pseudo into which it was copied. */
241 rtx internal_arg_pointer;
243 /* Opaque pointer used by get_hard_reg_initial_val and
244 has_hard_reg_initial_val (see integrate.[hc]). */
245 struct initial_value_struct *hard_reg_initial_vals;
247 /* List (chain of EXPR_LIST) of labels heading the current handlers for
249 rtx x_nonlocal_goto_handler_labels;
251 /* Label that will go on function epilogue.
252 Jumping to this label serves as a "return" instruction
253 on machines which require execution of the epilogue on all returns. */
256 /* Label that will go on the end of function epilogue.
257 Jumping to this label serves as a "naked return" instruction
258 on machines which require execution of the epilogue on all returns. */
259 rtx x_naked_return_label;
261 /* List (chain of EXPR_LISTs) of all stack slots in this function.
262 Made for the sake of unshare_all_rtl. */
263 rtx x_stack_slot_list;
265 /* Place after which to insert the tail_recursion_label if we need one. */
266 rtx x_stack_check_probe_note;
268 /* Location at which to save the argument pointer if it will need to be
269 referenced. There are two cases where this is done: if nonlocal gotos
270 exist, or if vars stored at an offset from the argument pointer will be
271 needed by inner routines. */
272 rtx x_arg_pointer_save_area;
274 /* Offset to end of allocated area of stack frame.
275 If stack grows down, this is the address of the last stack slot allocated.
276 If stack grows up, this is the address for the next slot. */
277 HOST_WIDE_INT x_frame_offset;
279 /* A PARM_DECL that should contain the static chain for this function.
280 It will be initialized at the beginning of the function. */
281 tree static_chain_decl;
283 /* An expression that contains the non-local goto save area. The first
284 word is the saved frame pointer and the second is the saved stack
286 tree nonlocal_goto_save_area;
288 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */
289 rtx x_parm_birth_insn;
291 /* List of all used temporaries allocated, by level. */
292 VEC(temp_slot_p,gc) *x_used_temp_slots;
294 /* List of available temp slots. */
295 struct temp_slot *x_avail_temp_slots;
297 /* This slot is initialized as 0 and is added to
298 during the nested function. */
299 struct var_refs_queue *fixup_var_refs_queue;
301 /* Current nesting level for temporaries. */
302 int x_temp_slot_level;
304 /* Highest label number in current function. */
305 int inl_max_label_num;
307 /* Function sequence number for profiling, debugging, etc. */
312 /* Highest loop depth seen so far in loop analysis. Used in flow.c
313 for the "failure strategy" when doing liveness analysis starting
314 with non-empty initial sets. */
319 /* tm.h can use this to store whatever it likes. */
320 struct machine_function * GTY ((maybe_undef)) machine;
322 /* The largest alignment of slot allocated on the stack. */
323 unsigned int stack_alignment_needed;
325 /* Preferred alignment of the end of stack frame. */
326 unsigned int preferred_stack_boundary;
328 /* Language-specific code can use this to store whatever it likes. */
329 struct language_function * language;
331 /* Used types hash table. */
332 htab_t GTY ((param_is (union tree_node))) used_types_hash;
336 /* If some insns can be deferred to the delay slots of the epilogue, the
337 delay list for them is recorded here. */
338 rtx epilogue_delay_list;
340 /* Maximal number of entities in the single jumptable. Used to estimate
341 final flowgraph size. */
342 int max_jumptable_ents;
344 /* UIDs for LABEL_DECLs. */
347 /* Line number of the end of the function. */
348 location_t function_end_locus;
350 /* Array mapping insn uids to blocks. */
351 VEC(tree,gc) *ib_boundaries_block;
353 /* The variables unexpanded so far. */
354 tree unexpanded_var_list;
356 /* Assembly labels for the hot and cold text sections, to
357 be used by debugger functions for determining the size of text
360 const char *hot_section_label;
361 const char *cold_section_label;
362 const char *hot_section_end_label;
363 const char *cold_section_end_label;
365 /* String to be used for name of cold text sections, via
366 targetm.asm_out.named_section. */
368 const char *unlikely_text_section_name;
370 /* A variable living at the top of the frame that holds a known value.
371 Used for detecting stack clobbers. */
372 tree stack_protect_guard;
374 /* Properties used by the pass manager. */
375 unsigned int curr_properties;
376 unsigned int last_verified;
378 /* Collected bit flags. */
380 /* Nonzero if function being compiled needs to be given an address
381 where the value should be stored. */
382 unsigned int returns_struct : 1;
384 /* Nonzero if function being compiled needs to
385 return the address of where it has put a structure value. */
386 unsigned int returns_pcc_struct : 1;
388 /* Nonzero if the current function returns a pointer type. */
389 unsigned int returns_pointer : 1;
391 /* Nonzero if function being compiled can call setjmp. */
392 unsigned int calls_setjmp : 1;
394 /* Nonzero if function being compiled can call alloca,
395 either as a subroutine or builtin. */
396 unsigned int calls_alloca : 1;
398 /* Nonzero if function being compiled called builtin_return_addr or
399 builtin_frame_address with nonzero count. */
400 unsigned int accesses_prior_frames : 1;
402 /* Nonzero if the function calls __builtin_eh_return. */
403 unsigned int calls_eh_return : 1;
405 /* Nonzero if function being compiled receives nonlocal gotos
406 from nested functions. */
407 unsigned int has_nonlocal_label : 1;
409 /* Nonzero if function being compiled has nonlocal gotos to parent
411 unsigned int has_nonlocal_goto : 1;
413 /* Nonzero if the current function is a thunk, i.e., a lightweight
414 function implemented by the output_mi_thunk hook) that just
415 adjusts one of its arguments and forwards to another
417 unsigned int is_thunk : 1;
419 /* This bit is used by the exception handling logic. It is set if all
420 calls (if any) are sibling calls. Such functions do not have to
421 have EH tables generated, as they cannot throw. A call to such a
422 function, however, should be treated as throwing if any of its callees
424 unsigned int all_throwers_are_sibcalls : 1;
426 /* Nonzero if profiling code should be generated. */
427 unsigned int profile : 1;
429 /* Nonzero if stack limit checking should be enabled in the current
431 unsigned int limit_stack : 1;
433 /* Nonzero if current function uses stdarg.h or equivalent. */
434 unsigned int stdarg : 1;
436 /* Nonzero if the back-end should not keep track of expressions that
437 determine the size of variable-sized objects. Normally, such
438 expressions are saved away, and then expanded when the next
439 function is started. For example, if a parameter has a
440 variable-sized type, then the size of the parameter is computed
441 when the function body is entered. However, some front-ends do
442 not desire this behavior. */
443 unsigned int x_dont_save_pending_sizes_p : 1;
445 /* Nonzero if the current function uses the constant pool. */
446 unsigned int uses_const_pool : 1;
448 /* Nonzero if the current function uses pic_offset_table_rtx. */
449 unsigned int uses_pic_offset_table : 1;
451 /* Nonzero if the current function needs an lsda for exception handling. */
452 unsigned int uses_eh_lsda : 1;
454 /* Nonzero if code to initialize arg_pointer_save_area has been emitted. */
455 unsigned int arg_pointer_save_area_init : 1;
457 unsigned int after_inlining : 1;
459 /* Set when the call to function itself has been emit. */
460 unsigned int recursive_call_emit : 1;
462 /* Set when the tail call has been produced. */
463 unsigned int tail_call_emit : 1;
465 /* How commonly executed the function is. Initialized during branch
466 probabilities pass. */
467 ENUM_BITFIELD (function_frequency) function_frequency : 2;
469 /* Number of units of general registers that need saving in stdarg
470 function. What unit is depends on the backend, either it is number
471 of bytes, or it can be number of registers. */
472 unsigned int va_list_gpr_size : 8;
474 /* Number of units of floating point registers that need saving in stdarg
476 unsigned int va_list_fpr_size : 8;
478 /* FIXME tuples: This bit is temporarily here to mark when a
479 function has been gimplified, so we can make sure we're not
480 creating non GIMPLE tuples after gimplification. */
481 unsigned gimplified : 1;
484 /* If va_list_[gf]pr_size is set to this, it means we don't know how
485 many units need to be saved. */
486 #define VA_LIST_MAX_GPR_SIZE 255
487 #define VA_LIST_MAX_FPR_SIZE 255
489 /* The function currently being compiled. */
490 extern GTY(()) struct function *cfun;
492 /* Pointer to chain of `struct function' for containing functions. */
493 extern GTY(()) struct function *outer_function_chain;
495 /* Nonzero if we've already converted virtual regs to hard regs. */
496 extern int virtuals_instantiated;
498 /* Nonzero if at least one trampoline has been created. */
499 extern int trampolines_created;
501 /* For backward compatibility... eventually these should all go away. */
502 #define current_function_pops_args (cfun->pops_args)
503 #define current_function_returns_struct (cfun->returns_struct)
504 #define current_function_returns_pcc_struct (cfun->returns_pcc_struct)
505 #define current_function_returns_pointer (cfun->returns_pointer)
506 #define current_function_calls_setjmp (cfun->calls_setjmp)
507 #define current_function_calls_alloca (cfun->calls_alloca)
508 #define current_function_accesses_prior_frames (cfun->accesses_prior_frames)
509 #define current_function_calls_eh_return (cfun->calls_eh_return)
510 #define current_function_is_thunk (cfun->is_thunk)
511 #define current_function_args_info (cfun->args_info)
512 #define current_function_args_size (cfun->args_size)
513 #define current_function_pretend_args_size (cfun->pretend_args_size)
514 #define current_function_outgoing_args_size (cfun->outgoing_args_size)
515 #define current_function_arg_offset_rtx (cfun->arg_offset_rtx)
516 #define current_function_stdarg (cfun->stdarg)
517 #define current_function_internal_arg_pointer (cfun->internal_arg_pointer)
518 #define current_function_return_rtx (cfun->return_rtx)
519 #define current_function_profile (cfun->profile)
520 #define current_function_funcdef_no (cfun->funcdef_no)
521 #define current_function_limit_stack (cfun->limit_stack)
522 #define current_function_uses_pic_offset_table (cfun->uses_pic_offset_table)
523 #define current_function_uses_const_pool (cfun->uses_const_pool)
524 #define current_function_epilogue_delay_list (cfun->epilogue_delay_list)
525 #define current_function_has_nonlocal_label (cfun->has_nonlocal_label)
526 #define current_function_has_nonlocal_goto (cfun->has_nonlocal_goto)
528 #define return_label (cfun->x_return_label)
529 #define naked_return_label (cfun->x_naked_return_label)
530 #define stack_slot_list (cfun->x_stack_slot_list)
531 #define parm_birth_insn (cfun->x_parm_birth_insn)
532 #define frame_offset (cfun->x_frame_offset)
533 #define stack_check_probe_note (cfun->x_stack_check_probe_note)
534 #define arg_pointer_save_area (cfun->x_arg_pointer_save_area)
535 #define used_temp_slots (cfun->x_used_temp_slots)
536 #define avail_temp_slots (cfun->x_avail_temp_slots)
537 #define temp_slot_level (cfun->x_temp_slot_level)
538 #define nonlocal_goto_handler_labels (cfun->x_nonlocal_goto_handler_labels)
539 #define current_loops (cfun->x_current_loops)
540 #define VALUE_HISTOGRAMS(fun) (fun)->value_histograms
542 /* Given a function decl for a containing function,
543 return the `struct function' for it. */
544 struct function *find_function_data (tree);
546 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
547 and create duplicate blocks. */
548 extern void reorder_blocks (void);
550 /* Set BLOCK_NUMBER for all the blocks in FN. */
551 extern void number_blocks (tree);
553 extern void clear_block_marks (tree);
554 extern tree blocks_nreverse (tree);
555 extern void reset_block_changes (void);
556 extern void record_block_change (tree);
557 extern void finalize_block_changes (void);
558 extern void check_block_change (rtx, tree *);
559 extern void free_block_changes (void);
561 /* Return size needed for stack frame based on slots so far allocated.
562 This size counts from zero. It is not rounded to STACK_BOUNDARY;
563 the caller may have to do that. */
564 extern HOST_WIDE_INT get_frame_size (void);
566 /* Issue an error message and return TRUE if frame OFFSET overflows in
567 the signed target pointer arithmetics for function FUNC. Otherwise
569 extern bool frame_offset_overflow (HOST_WIDE_INT, tree);
571 /* A pointer to a function to create target specific, per-function
573 extern struct machine_function * (*init_machine_status) (void);
575 /* Save and restore status information for a nested function. */
576 extern void free_after_parsing (struct function *);
577 extern void free_after_compilation (struct function *);
579 extern void init_varasm_status (struct function *);
582 extern void diddle_return_value (void (*)(rtx, void*), void*);
583 extern void clobber_return_register (void);
586 extern rtx get_arg_pointer_save_area (struct function *);
588 /* Returns the name of the current function. */
589 extern const char *current_function_name (void);
591 extern void do_warn_unused_parameter (tree);
593 extern bool pass_by_reference (CUMULATIVE_ARGS *, enum machine_mode,
595 extern bool reference_callee_copied (CUMULATIVE_ARGS *, enum machine_mode,
598 extern void used_types_insert (tree);
600 extern int get_next_funcdef_no (void);
601 #endif /* GCC_FUNCTION_H */