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, 59 Temple Place - Suite 330, Boston, MA
22 #ifndef GCC_FUNCTION_H
23 #define GCC_FUNCTION_H
25 struct var_refs_queue GTY(())
28 enum machine_mode promoted_mode;
30 struct var_refs_queue *next;
33 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
34 Each element describes one pending sequence.
35 The main insn-chain is saved in the last element of the chain,
36 unless the chain is empty. */
38 struct sequence_stack GTY(())
40 /* First and last insns in the chain of the saved sequence. */
43 struct sequence_stack *next;
46 extern struct sequence_stack *sequence_stack;
48 /* Stack of single obstacks. */
50 struct simple_obstack_stack
52 struct obstack *obstack;
53 struct simple_obstack_stack *next;
56 struct emit_status GTY(())
58 /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
59 After rtl generation, it is 1 plus the largest register number used. */
62 /* Lowest label number in current function. */
63 int x_first_label_num;
65 /* The ends of the doubly-linked chain of rtl for the current function.
66 Both are reset to null at the start of rtl generation for the function.
68 start_sequence saves both of these on `sequence_stack' and then starts
69 a new, nested sequence of insns. */
73 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
74 Each element describes one pending sequence.
75 The main insn-chain is saved in the last element of the chain,
76 unless the chain is empty. */
77 struct sequence_stack *sequence_stack;
79 /* INSN_UID for next insn emitted.
80 Reset to 1 for each function compiled. */
83 /* Location the last line-number NOTE emitted.
84 This is used to avoid generating duplicates. */
85 location_t x_last_location;
87 /* The length of the regno_pointer_align, regno_decl, and x_regno_reg_rtx
88 vectors. Since these vectors are needed during the expansion phase when
89 the total number of registers in the function is not yet known, the
90 vectors are copied and made bigger when necessary. */
91 int regno_pointer_align_length;
93 /* Indexed by pseudo register number, if nonzero gives the known alignment
94 for that pseudo (if REG_POINTER is set in x_regno_reg_rtx).
95 Allocated in parallel with x_regno_reg_rtx. */
96 unsigned char * GTY ((length ("%h.x_reg_rtx_no")))
99 /* Indexed by pseudo register number, gives the rtx for that pseudo.
100 Allocated in parallel with regno_pointer_align. */
101 rtx * GTY ((length ("%h.x_reg_rtx_no"))) x_regno_reg_rtx;
104 /* For backward compatibility... eventually these should all go away. */
105 #define reg_rtx_no (cfun->emit->x_reg_rtx_no)
106 #define regno_reg_rtx (cfun->emit->x_regno_reg_rtx)
107 #define seq_stack (cfun->emit->sequence_stack)
109 #define REGNO_POINTER_ALIGN(REGNO) (cfun->emit->regno_pointer_align[REGNO])
111 struct expr_status GTY(())
113 /* Number of units that we should eventually pop off the stack.
114 These are the arguments to function calls that have already returned. */
115 int x_pending_stack_adjust;
117 /* Under some ABIs, it is the caller's responsibility to pop arguments
118 pushed for function calls. A naive implementation would simply pop
119 the arguments immediately after each call. However, if several
120 function calls are made in a row, it is typically cheaper to pop
121 all the arguments after all of the calls are complete since a
122 single pop instruction can be used. Therefore, GCC attempts to
123 defer popping the arguments until absolutely necessary. (For
124 example, at the end of a conditional, the arguments must be popped,
125 since code outside the conditional won't know whether or not the
126 arguments need to be popped.)
128 When INHIBIT_DEFER_POP is nonzero, however, the compiler does not
129 attempt to defer pops. Instead, the stack is popped immediately
130 after each call. Rather then setting this variable directly, use
131 NO_DEFER_POP and OK_DEFER_POP. */
132 int x_inhibit_defer_pop;
134 /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack
135 boundary can be momentarily unaligned while pushing the arguments.
136 Record the delta since last aligned boundary here in order to get
137 stack alignment in the nested function calls working right. */
138 int x_stack_pointer_delta;
140 /* Nonzero means __builtin_saveregs has already been done in this function.
141 The value is the pseudoreg containing the value __builtin_saveregs
143 rtx x_saveregs_value;
145 /* Similarly for __builtin_apply_args. */
146 rtx x_apply_args_value;
148 /* List of labels that must never be deleted. */
152 #define pending_stack_adjust (cfun->expr->x_pending_stack_adjust)
153 #define inhibit_defer_pop (cfun->expr->x_inhibit_defer_pop)
154 #define saveregs_value (cfun->expr->x_saveregs_value)
155 #define apply_args_value (cfun->expr->x_apply_args_value)
156 #define forced_labels (cfun->expr->x_forced_labels)
157 #define stack_pointer_delta (cfun->expr->x_stack_pointer_delta)
159 /* This structure can save all the important global and static variables
160 describing the status of the current function. */
162 struct function GTY(())
164 struct eh_status *eh;
165 struct expr_status *expr;
166 struct emit_status *emit;
167 struct varasm_status *varasm;
169 /* The control flow graph for this function. */
170 struct control_flow_graph *cfg;
173 /* For tree-optimize.c. */
175 /* Saved tree and arguments during tree optimization. Used later for
179 tree saved_static_chain_decl;
181 /* For function.c. */
183 /* Points to the FUNCTION_DECL of this function. */
186 /* Function containing this function, if any. */
187 struct function *outer;
189 /* Number of bytes of args popped by function being compiled on its return.
190 Zero if no bytes are to be popped.
191 May affect compilation of return insn or of function epilogue. */
194 /* If function's args have a fixed size, this is that size, in bytes.
196 May affect compilation of return insn or of function epilogue. */
199 /* # bytes the prologue should push and pretend that the caller pushed them.
200 The prologue must do this, but only if parms can be passed in
202 int pretend_args_size;
204 /* # of bytes of outgoing arguments. If ACCUMULATE_OUTGOING_ARGS is
205 defined, the needed space is pushed by the prologue. */
206 int outgoing_args_size;
208 /* This is the offset from the arg pointer to the place where the first
209 anonymous arg can be found, if there is one. */
212 /* Quantities of various kinds of registers
213 used for the current function's args. */
214 CUMULATIVE_ARGS args_info;
216 /* If nonzero, an RTL expression for the location at which the current
217 function returns its result. If the current function returns its
218 result in a register, current_function_return_rtx will always be
219 the hard register containing the result. */
222 /* The arg pointer hard register, or the pseudo into which it was copied. */
223 rtx internal_arg_pointer;
225 /* Opaque pointer used by get_hard_reg_initial_val and
226 has_hard_reg_initial_val (see integrate.[hc]). */
227 struct initial_value_struct *hard_reg_initial_vals;
229 /* List (chain of EXPR_LIST) of labels heading the current handlers for
231 rtx x_nonlocal_goto_handler_labels;
233 /* Label that will go on function epilogue.
234 Jumping to this label serves as a "return" instruction
235 on machines which require execution of the epilogue on all returns. */
238 /* Label that will go on the end of function epilogue.
239 Jumping to this label serves as a "naked return" instruction
240 on machines which require execution of the epilogue on all returns. */
241 rtx x_naked_return_label;
243 /* List (chain of EXPR_LISTs) of all stack slots in this function.
244 Made for the sake of unshare_all_rtl. */
245 rtx x_stack_slot_list;
247 /* Place after which to insert the tail_recursion_label if we need one. */
248 rtx x_tail_recursion_reentry;
250 /* Location at which to save the argument pointer if it will need to be
251 referenced. There are two cases where this is done: if nonlocal gotos
252 exist, or if vars stored at an offset from the argument pointer will be
253 needed by inner routines. */
254 rtx x_arg_pointer_save_area;
256 /* Offset to end of allocated area of stack frame.
257 If stack grows down, this is the address of the last stack slot allocated.
258 If stack grows up, this is the address for the next slot. */
259 HOST_WIDE_INT x_frame_offset;
261 /* A PARM_DECL that should contain the static chain for this function.
262 It will be initialized at the beginning of the function. */
263 tree static_chain_decl;
265 /* An expression that contains the non-local goto save area. The first
266 word is the saved frame pointer and the second is the saved stack
268 tree nonlocal_goto_save_area;
270 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */
271 rtx x_parm_birth_insn;
273 /* List of all used temporaries allocated, by level. */
274 struct varray_head_tag * GTY((param_is (struct temp_slot))) x_used_temp_slots;
276 /* List of available temp slots. */
277 struct temp_slot *x_avail_temp_slots;
279 /* Current nesting level for temporaries. */
280 int x_temp_slot_level;
282 /* This slot is initialized as 0 and is added to
283 during the nested function. */
284 struct var_refs_queue *fixup_var_refs_queue;
286 /* For integrate.c. */
288 int no_debugging_symbols;
289 rtvec original_arg_vector;
290 tree original_decl_initial;
292 /* Highest label number in current function. */
293 int inl_max_label_num;
295 /* Function sequence number for profiling, debugging, etc. */
300 /* Highest loop depth seen so far in loop analysis. Used in flow.c
301 for the "failure strategy" when doing liveness analysis starting
302 with non-empty initial sets. */
307 /* tm.h can use this to store whatever it likes. */
308 struct machine_function * GTY ((maybe_undef)) machine;
309 /* The largest alignment of slot allocated on the stack. */
310 unsigned int stack_alignment_needed;
311 /* Preferred alignment of the end of stack frame. */
312 unsigned int preferred_stack_boundary;
313 /* Set when the call to function itself has been emit. */
314 bool recursive_call_emit;
315 /* Set when the tail call has been produced. */
318 /* Language-specific code can use this to store whatever it likes. */
319 struct language_function * language;
323 /* If some insns can be deferred to the delay slots of the epilogue, the
324 delay list for them is recorded here. */
325 rtx epilogue_delay_list;
327 /* How commonly executed the function is. Initialized during branch
328 probabilities pass. */
329 enum function_frequency {
330 /* This function most likely won't be executed at all.
331 (set only when profile feedback is available). */
332 FUNCTION_FREQUENCY_UNLIKELY_EXECUTED,
333 /* The default value. */
334 FUNCTION_FREQUENCY_NORMAL,
335 /* Optimize this function hard
336 (set only when profile feedback is available). */
337 FUNCTION_FREQUENCY_HOT
338 } function_frequency;
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 struct varray_head_tag *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 /* Collected bit flags. */
372 /* Nonzero if function being compiled needs to be given an address
373 where the value should be stored. */
374 unsigned int returns_struct : 1;
376 /* Nonzero if function being compiled needs to
377 return the address of where it has put a structure value. */
378 unsigned int returns_pcc_struct : 1;
380 /* Nonzero if the current function returns a pointer type. */
381 unsigned int returns_pointer : 1;
383 /* Nonzero if function being compiled can call setjmp. */
384 unsigned int calls_setjmp : 1;
386 /* Nonzero if function being compiled can call alloca,
387 either as a subroutine or builtin. */
388 unsigned int calls_alloca : 1;
390 /* Nonzero if the function calls __builtin_eh_return. */
391 unsigned int calls_eh_return : 1;
393 /* Nonzero if function being compiled receives nonlocal gotos
394 from nested functions. */
395 unsigned int has_nonlocal_label : 1;
397 /* Nonzero if function being compiled has nonlocal gotos to parent
399 unsigned int has_nonlocal_goto : 1;
401 /* Nonzero if the current function is a thunk, i.e., a lightweight
402 function implemented by the output_mi_thunk hook) that just
403 adjusts one of its arguments and forwards to another
405 unsigned int is_thunk : 1;
407 /* This bit is used by the exception handling logic. It is set if all
408 calls (if any) are sibling calls. Such functions do not have to
409 have EH tables generated, as they cannot throw. A call to such a
410 function, however, should be treated as throwing if any of its callees
412 unsigned int all_throwers_are_sibcalls : 1;
414 /* Nonzero if profiling code should be generated. */
415 unsigned int profile : 1;
417 /* Nonzero if stack limit checking should be enabled in the current
419 unsigned int limit_stack : 1;
421 /* Nonzero if current function uses stdarg.h or equivalent. */
422 unsigned int stdarg : 1;
424 /* Nonzero if the back-end should not keep track of expressions that
425 determine the size of variable-sized objects. Normally, such
426 expressions are saved away, and then expanded when the next
427 function is started. For example, if a parameter has a
428 variable-sized type, then the size of the parameter is computed
429 when the function body is entered. However, some front-ends do
430 not desire this behavior. */
431 unsigned int x_dont_save_pending_sizes_p : 1;
433 /* Nonzero if the current function uses the constant pool. */
434 unsigned int uses_const_pool : 1;
436 /* Nonzero if the current function uses pic_offset_table_rtx. */
437 unsigned int uses_pic_offset_table : 1;
439 /* Nonzero if the current function needs an lsda for exception handling. */
440 unsigned int uses_eh_lsda : 1;
442 /* Nonzero if code to initialize arg_pointer_save_area has been emitted. */
443 unsigned int arg_pointer_save_area_init : 1;
445 /* Number of units of general registers that need saving in stdarg
446 function. What unit is depends on the backend, either it is number
447 of bytes, or it can be number of registers. */
448 unsigned int va_list_gpr_size : 8;
450 /* Number of units of floating point registers that need saving in stdarg
452 unsigned int va_list_fpr_size : 8;
455 /* If va_list_[gf]pr_size is set to this, it means we don't know how
456 many units need to be saved. */
457 #define VA_LIST_MAX_GPR_SIZE 255
458 #define VA_LIST_MAX_FPR_SIZE 255
460 /* The function currently being compiled. */
461 extern GTY(()) struct function *cfun;
463 /* Pointer to chain of `struct function' for containing functions. */
464 extern GTY(()) struct function *outer_function_chain;
466 /* Nonzero if we've already converted virtual regs to hard regs. */
467 extern int virtuals_instantiated;
469 /* Nonzero if at least one trampoline has been created. */
470 extern int trampolines_created;
472 /* For backward compatibility... eventually these should all go away. */
473 #define current_function_pops_args (cfun->pops_args)
474 #define current_function_returns_struct (cfun->returns_struct)
475 #define current_function_returns_pcc_struct (cfun->returns_pcc_struct)
476 #define current_function_returns_pointer (cfun->returns_pointer)
477 #define current_function_calls_setjmp (cfun->calls_setjmp)
478 #define current_function_calls_alloca (cfun->calls_alloca)
479 #define current_function_calls_eh_return (cfun->calls_eh_return)
480 #define current_function_is_thunk (cfun->is_thunk)
481 #define current_function_args_info (cfun->args_info)
482 #define current_function_args_size (cfun->args_size)
483 #define current_function_pretend_args_size (cfun->pretend_args_size)
484 #define current_function_outgoing_args_size (cfun->outgoing_args_size)
485 #define current_function_arg_offset_rtx (cfun->arg_offset_rtx)
486 #define current_function_stdarg (cfun->stdarg)
487 #define current_function_internal_arg_pointer (cfun->internal_arg_pointer)
488 #define current_function_return_rtx (cfun->return_rtx)
489 #define current_function_profile (cfun->profile)
490 #define current_function_funcdef_no (cfun->funcdef_no)
491 #define current_function_limit_stack (cfun->limit_stack)
492 #define current_function_uses_pic_offset_table (cfun->uses_pic_offset_table)
493 #define current_function_uses_const_pool (cfun->uses_const_pool)
494 #define current_function_epilogue_delay_list (cfun->epilogue_delay_list)
495 #define current_function_has_nonlocal_label (cfun->has_nonlocal_label)
496 #define current_function_has_nonlocal_goto (cfun->has_nonlocal_goto)
498 #define return_label (cfun->x_return_label)
499 #define naked_return_label (cfun->x_naked_return_label)
500 #define stack_slot_list (cfun->x_stack_slot_list)
501 #define parm_birth_insn (cfun->x_parm_birth_insn)
502 #define frame_offset (cfun->x_frame_offset)
503 #define tail_recursion_reentry (cfun->x_tail_recursion_reentry)
504 #define arg_pointer_save_area (cfun->x_arg_pointer_save_area)
505 #define used_temp_slots (cfun->x_used_temp_slots)
506 #define avail_temp_slots (cfun->x_avail_temp_slots)
507 #define temp_slot_level (cfun->x_temp_slot_level)
508 #define nonlocal_goto_handler_labels (cfun->x_nonlocal_goto_handler_labels)
510 /* Given a function decl for a containing function,
511 return the `struct function' for it. */
512 struct function *find_function_data (tree);
514 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
515 and create duplicate blocks. */
516 extern void reorder_blocks (void);
518 /* Set BLOCK_NUMBER for all the blocks in FN. */
519 extern void number_blocks (tree);
521 extern void clear_block_marks (tree);
522 extern tree blocks_nreverse (tree);
523 extern void reset_block_changes (void);
524 extern void record_block_change (tree);
525 extern void finalize_block_changes (void);
526 extern void check_block_change (rtx, tree *);
527 extern void free_block_changes (void);
529 /* Return size needed for stack frame based on slots so far allocated.
530 This size counts from zero. It is not rounded to STACK_BOUNDARY;
531 the caller may have to do that. */
532 extern HOST_WIDE_INT get_frame_size (void);
534 /* A pointer to a function to create target specific, per-function
536 extern struct machine_function * (*init_machine_status) (void);
538 /* Save and restore status information for a nested function. */
539 extern void free_after_parsing (struct function *);
540 extern void free_after_compilation (struct function *);
542 extern void init_varasm_status (struct function *);
545 extern void diddle_return_value (void (*)(rtx, void*), void*);
546 extern void clobber_return_register (void);
547 extern void use_return_register (void);
550 extern rtx get_arg_pointer_save_area (struct function *);
552 extern void init_virtual_regs (struct emit_status *);
553 extern void instantiate_virtual_regs (void);
555 /* Returns the name of the current function. */
556 extern const char *current_function_name (void);
558 /* Called once, at initialization, to initialize function.c. */
559 extern void init_function_once (void);
561 extern void do_warn_unused_parameter (tree);
563 extern bool pass_by_reference (CUMULATIVE_ARGS *, enum machine_mode,
565 extern bool reference_callee_copied (CUMULATIVE_ARGS *, enum machine_mode,
568 #endif /* GCC_FUNCTION_H */