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 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 tree sequence_rtl_expr
;
44 struct sequence_stack
*next
;
47 extern struct sequence_stack
*sequence_stack
;
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' along with
70 `sequence_rtl_expr' and then starts a new, nested sequence of insns. */
74 /* RTL_EXPR within which the current sequence will be placed. Use to
75 prevent reuse of any temporaries within the sequence until after the
76 RTL_EXPR is emitted. */
77 tree sequence_rtl_expr
;
79 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
80 Each element describes one pending sequence.
81 The main insn-chain is saved in the last element of the chain,
82 unless the chain is empty. */
83 struct sequence_stack
*sequence_stack
;
85 /* INSN_UID for next insn emitted.
86 Reset to 1 for each function compiled. */
89 /* Location the last line-number NOTE emitted.
90 This is used to avoid generating duplicates. */
91 location_t x_last_location
;
93 /* The length of the regno_pointer_align, regno_decl, and x_regno_reg_rtx
94 vectors. Since these vectors are needed during the expansion phase when
95 the total number of registers in the function is not yet known, the
96 vectors are copied and made bigger when necessary. */
97 int regno_pointer_align_length
;
99 /* Indexed by pseudo register number, if nonzero gives the known alignment
100 for that pseudo (if REG_POINTER is set in x_regno_reg_rtx).
101 Allocated in parallel with x_regno_reg_rtx. */
102 unsigned char * GTY ((length ("%h.x_reg_rtx_no")))
105 /* Indexed by pseudo register number, gives the rtx for that pseudo.
106 Allocated in parallel with regno_pointer_align.
108 Note MEM expressions can appear in this array due to the actions
109 of put_var_into_stack. */
110 rtx
* GTY ((length ("%h.x_reg_rtx_no"))) x_regno_reg_rtx
;
113 /* For backward compatibility... eventually these should all go away. */
114 #define reg_rtx_no (cfun->emit->x_reg_rtx_no)
115 #define seq_rtl_expr (cfun->emit->sequence_rtl_expr)
116 #define regno_reg_rtx (cfun->emit->x_regno_reg_rtx)
117 #define seq_stack (cfun->emit->sequence_stack)
119 #define REGNO_POINTER_ALIGN(REGNO) (cfun->emit->regno_pointer_align[REGNO])
121 struct expr_status
GTY(())
123 /* Number of units that we should eventually pop off the stack.
124 These are the arguments to function calls that have already returned. */
125 int x_pending_stack_adjust
;
127 /* Under some ABIs, it is the caller's responsibility to pop arguments
128 pushed for function calls. A naive implementation would simply pop
129 the arguments immediately after each call. However, if several
130 function calls are made in a row, it is typically cheaper to pop
131 all the arguments after all of the calls are complete since a
132 single pop instruction can be used. Therefore, GCC attempts to
133 defer popping the arguments until absolutely necessary. (For
134 example, at the end of a conditional, the arguments must be popped,
135 since code outside the conditional won't know whether or not the
136 arguments need to be popped.)
138 When INHIBIT_DEFER_POP is nonzero, however, the compiler does not
139 attempt to defer pops. Instead, the stack is popped immediately
140 after each call. Rather then setting this variable directly, use
141 NO_DEFER_POP and OK_DEFER_POP. */
142 int x_inhibit_defer_pop
;
144 /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack
145 boundary can be momentarily unaligned while pushing the arguments.
146 Record the delta since last aligned boundary here in order to get
147 stack alignment in the nested function calls working right. */
148 int x_stack_pointer_delta
;
150 /* Nonzero means __builtin_saveregs has already been done in this function.
151 The value is the pseudoreg containing the value __builtin_saveregs
153 rtx x_saveregs_value
;
155 /* Similarly for __builtin_apply_args. */
156 rtx x_apply_args_value
;
158 /* List of labels that must never be deleted. */
161 /* Postincrements that still need to be expanded. */
165 #define pending_stack_adjust (cfun->expr->x_pending_stack_adjust)
166 #define inhibit_defer_pop (cfun->expr->x_inhibit_defer_pop)
167 #define saveregs_value (cfun->expr->x_saveregs_value)
168 #define apply_args_value (cfun->expr->x_apply_args_value)
169 #define forced_labels (cfun->expr->x_forced_labels)
170 #define pending_chain (cfun->expr->x_pending_chain)
171 #define stack_pointer_delta (cfun->expr->x_stack_pointer_delta)
173 /* This structure can save all the important global and static variables
174 describing the status of the current function. */
176 struct function
GTY(())
178 struct eh_status
*eh
;
179 struct stmt_status
*stmt
;
180 struct expr_status
*expr
;
181 struct emit_status
*emit
;
182 struct varasm_status
*varasm
;
184 /* For tree-optimize.c. */
186 /* Saved tree and arguments during tree optimization. Used later for
191 /* For function.c. */
193 /* Points to the FUNCTION_DECL of this function. */
196 /* Function containing this function, if any. */
197 struct function
*outer
;
199 /* Number of bytes of args popped by function being compiled on its return.
200 Zero if no bytes are to be popped.
201 May affect compilation of return insn or of function epilogue. */
204 /* If function's args have a fixed size, this is that size, in bytes.
206 May affect compilation of return insn or of function epilogue. */
209 /* # bytes the prologue should push and pretend that the caller pushed them.
210 The prologue must do this, but only if parms can be passed in
212 int pretend_args_size
;
214 /* # of bytes of outgoing arguments. If ACCUMULATE_OUTGOING_ARGS is
215 defined, the needed space is pushed by the prologue. */
216 int outgoing_args_size
;
218 /* This is the offset from the arg pointer to the place where the first
219 anonymous arg can be found, if there is one. */
222 /* Quantities of various kinds of registers
223 used for the current function's args. */
224 CUMULATIVE_ARGS args_info
;
226 /* If nonzero, an RTL expression for the location at which the current
227 function returns its result. If the current function returns its
228 result in a register, current_function_return_rtx will always be
229 the hard register containing the result. */
232 /* The arg pointer hard register, or the pseudo into which it was copied. */
233 rtx internal_arg_pointer
;
235 /* Language-specific reason why the current function cannot be made
237 const char *cannot_inline
;
239 /* Opaque pointer used by get_hard_reg_initial_val and
240 has_hard_reg_initial_val (see integrate.[hc]). */
241 struct initial_value_struct
*hard_reg_initial_vals
;
243 /* Number of function calls seen so far in current function. */
244 int x_function_call_count
;
246 /* List (chain of EXPR_LIST) of labels heading the current handlers for
248 rtx x_nonlocal_goto_handler_labels
;
250 /* Label that will go on parm cleanup code, if any.
251 Jumping to this label runs cleanup code for parameters, if
252 such code must be run. Following this code is the logical return
256 /* Label that will go on function epilogue.
257 Jumping to this label serves as a "return" instruction
258 on machines which require execution of the epilogue on all returns. */
261 /* Label that will go on the end of function epilogue.
262 Jumping to this label serves as a "naked return" instruction
263 on machines which require execution of the epilogue on all returns. */
264 rtx x_naked_return_label
;
266 /* Label and register for unswitching computed gotos. */
267 rtx computed_goto_common_label
;
268 rtx computed_goto_common_reg
;
270 /* List (chain of EXPR_LISTs) of pseudo-regs of SAVE_EXPRs.
271 So we can mark them all live at the end of the function, if nonopt. */
272 rtx x_save_expr_regs
;
274 /* List (chain of EXPR_LISTs) of all stack slots in this function.
275 Made for the sake of unshare_all_rtl. */
276 rtx x_stack_slot_list
;
278 /* Chain of all RTL_EXPRs that have insns in them. */
279 tree x_rtl_expr_chain
;
281 /* Place after which to insert the tail_recursion_label if we need one. */
282 rtx x_tail_recursion_reentry
;
284 /* Location at which to save the argument pointer if it will need to be
285 referenced. There are two cases where this is done: if nonlocal gotos
286 exist, or if vars stored at an offset from the argument pointer will be
287 needed by inner routines. */
288 rtx x_arg_pointer_save_area
;
290 /* Offset to end of allocated area of stack frame.
291 If stack grows down, this is the address of the last stack slot allocated.
292 If stack grows up, this is the address for the next slot. */
293 HOST_WIDE_INT x_frame_offset
;
295 /* A VAR_DECL that should contain the static chain for this function.
296 It will be initialized at the beginning of the function. */
297 tree static_chain_decl
;
299 /* An expression that contains the non-local goto save area. The first
300 word is the saved frame pointer and the second is the saved stack
302 tree nonlocal_goto_save_area
;
304 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */
305 rtx x_parm_birth_insn
;
307 /* Last insn of those whose job was to put parms into their nominal
309 rtx x_last_parm_insn
;
311 /* 1 + last pseudo register number possibly used for loading a copy
312 of a parameter of this function. */
313 unsigned int x_max_parm_reg
;
315 /* Vector indexed by REGNO, containing location on stack in which
316 to put the parm which is nominally in pseudo register REGNO,
317 if we discover that that parm must go in the stack. The highest
318 element in this vector is one less than MAX_PARM_REG, above. */
319 rtx
* GTY ((length ("%h.x_max_parm_reg"))) x_parm_reg_stack_loc
;
321 /* List of all used temporaries allocated, by level. */
322 struct varray_head_tag
* GTY((param_is (struct temp_slot
))) x_used_temp_slots
;
324 /* List of available temp slots. */
325 struct temp_slot
*x_avail_temp_slots
;
327 /* Current nesting level for temporaries. */
328 int x_temp_slot_level
;
330 /* Current nesting level for variables in a block. */
331 int x_var_temp_slot_level
;
333 /* When temporaries are created by TARGET_EXPRs, they are created at
334 this level of temp_slot_level, so that they can remain allocated
335 until no longer needed. CLEANUP_POINT_EXPRs define the lifetime
337 int x_target_temp_slot_level
;
339 /* This slot is initialized as 0 and is added to
340 during the nested function. */
341 struct var_refs_queue
*fixup_var_refs_queue
;
343 /* For integrate.c. */
345 int no_debugging_symbols
;
346 rtvec original_arg_vector
;
347 tree original_decl_initial
;
348 /* Last insn of those whose job was to put parms into their nominal
350 rtx inl_last_parm_insn
;
351 /* Highest label number in current function. */
352 int inl_max_label_num
;
354 /* Function sequence number for profiling, debugging, etc. */
359 /* tm.h can use this to store whatever it likes. */
360 struct machine_function
* GTY ((maybe_undef
)) machine
;
361 /* The largest alignment of slot allocated on the stack. */
362 int stack_alignment_needed
;
363 /* Preferred alignment of the end of stack frame. */
364 int preferred_stack_boundary
;
365 /* Set when the call to function itself has been emit. */
366 bool recursive_call_emit
;
367 /* Set when the tail call has been produced. */
370 /* Language-specific code can use this to store whatever it likes. */
371 struct language_function
* language
;
375 /* If some insns can be deferred to the delay slots of the epilogue, the
376 delay list for them is recorded here. */
377 rtx epilogue_delay_list
;
379 /* Nonzero if NOTE_INSN_BLOCK_BEG / NOTE_INSN_BLOCK_END notes should not
381 unsigned int dont_emit_block_notes
: 1;
383 /* How commonly executed the function is. Initialized during branch
384 probabilities pass. */
385 enum function_frequency
{
386 /* This function most likely won't be executed at all.
387 (set only when profile feedback is available). */
388 FUNCTION_FREQUENCY_UNLIKELY_EXECUTED
,
389 /* The default value. */
390 FUNCTION_FREQUENCY_NORMAL
,
391 /* Optimize this function hard
392 (set only when profile feedback is available). */
393 FUNCTION_FREQUENCY_HOT
394 } function_frequency
;
396 /* Maximal number of entities in the single jumptable. Used to estimate
397 final flowgraph size. */
398 int max_jumptable_ents
;
400 /* UIDs for LABEL_DECLs. */
403 /* Line number of the end of the function. */
404 location_t function_end_locus
;
406 /* Array mapping insn uids to blocks. */
407 struct varray_head_tag
*ib_boundaries_block
;
409 /* The variables unexpanded so far. */
410 tree unexpanded_var_list
;
412 /* Collected bit flags. */
414 /* Nonzero if function being compiled needs to be given an address
415 where the value should be stored. */
416 unsigned int returns_struct
: 1;
418 /* Nonzero if function being compiled needs to
419 return the address of where it has put a structure value. */
420 unsigned int returns_pcc_struct
: 1;
422 /* Nonzero if the current function returns a pointer type. */
423 unsigned int returns_pointer
: 1;
425 /* Nonzero if function being compiled can call setjmp. */
426 unsigned int calls_setjmp
: 1;
428 /* Nonzero if function being compiled can call longjmp. */
429 unsigned int calls_longjmp
: 1;
431 /* Nonzero if function being compiled can call alloca,
432 either as a subroutine or builtin. */
433 unsigned int calls_alloca
: 1;
435 /* Nonzero if the function calls __builtin_eh_return. */
436 unsigned int calls_eh_return
: 1;
438 /* Nonzero if function being compiled receives nonlocal gotos
439 from nested functions. */
440 unsigned int has_nonlocal_label
: 1;
442 /* Nonzero if function being compiled has nonlocal gotos to parent
444 unsigned int has_nonlocal_goto
: 1;
446 /* Nonzero if function being compiled contains nested functions. */
447 unsigned int contains_functions
: 1;
449 /* Nonzero if the function being compiled issues a computed jump. */
450 unsigned int has_computed_jump
: 1;
452 /* Nonzero if the current function is a thunk, i.e., a lightweight
453 function implemented by the output_mi_thunk hook) that just
454 adjusts one of its arguments and forwards to another
456 unsigned int is_thunk
: 1;
458 /* This bit is used by the exception handling logic. It is set if all
459 calls (if any) are sibling calls. Such functions do not have to
460 have EH tables generated, as they cannot throw. A call to such a
461 function, however, should be treated as throwing if any of its callees
463 unsigned int all_throwers_are_sibcalls
: 1;
465 /* Nonzero if instrumentation calls for function entry and exit should be
467 unsigned int instrument_entry_exit
: 1;
469 /* Nonzero if profiling code should be generated. */
470 unsigned int profile
: 1;
472 /* Nonzero if stack limit checking should be enabled in the current
474 unsigned int limit_stack
: 1;
476 /* Nonzero if current function uses stdarg.h or equivalent. */
477 unsigned int stdarg
: 1;
479 /* Nonzero if this function is being processed in function-at-a-time
480 mode. In other words, if all tree structure for this function,
481 including the BLOCK tree, is created before RTL generation
483 unsigned int x_whole_function_mode_p
: 1;
485 /* Nonzero if the back-end should not keep track of expressions that
486 determine the size of variable-sized objects. Normally, such
487 expressions are saved away, and then expanded when the next
488 function is started. For example, if a parameter has a
489 variable-sized type, then the size of the parameter is computed
490 when the function body is entered. However, some front-ends do
491 not desire this behavior. */
492 unsigned int x_dont_save_pending_sizes_p
: 1;
494 /* Nonzero if the current function uses the constant pool. */
495 unsigned int uses_const_pool
: 1;
497 /* Nonzero if the current function uses pic_offset_table_rtx. */
498 unsigned int uses_pic_offset_table
: 1;
500 /* Nonzero if the current function needs an lsda for exception handling. */
501 unsigned int uses_eh_lsda
: 1;
503 /* Nonzero if code to initialize arg_pointer_save_area has been emitted. */
504 unsigned int arg_pointer_save_area_init
: 1;
507 /* The function currently being compiled. */
508 extern GTY(()) struct function
*cfun
;
510 /* Pointer to chain of `struct function' for containing functions. */
511 extern GTY(()) struct function
*outer_function_chain
;
513 /* Nonzero if we've already converted virtual regs to hard regs. */
514 extern int virtuals_instantiated
;
516 /* Nonzero if at least one trampoline has been created. */
517 extern int trampolines_created
;
519 /* For backward compatibility... eventually these should all go away. */
520 #define current_function_pops_args (cfun->pops_args)
521 #define current_function_returns_struct (cfun->returns_struct)
522 #define current_function_returns_pcc_struct (cfun->returns_pcc_struct)
523 #define current_function_returns_pointer (cfun->returns_pointer)
524 #define current_function_calls_setjmp (cfun->calls_setjmp)
525 #define current_function_calls_alloca (cfun->calls_alloca)
526 #define current_function_calls_longjmp (cfun->calls_longjmp)
527 #define current_function_calls_eh_return (cfun->calls_eh_return)
528 #define current_function_has_computed_jump (cfun->has_computed_jump)
529 #define current_function_contains_functions (cfun->contains_functions)
530 #define current_function_is_thunk (cfun->is_thunk)
531 #define current_function_args_info (cfun->args_info)
532 #define current_function_args_size (cfun->args_size)
533 #define current_function_pretend_args_size (cfun->pretend_args_size)
534 #define current_function_outgoing_args_size (cfun->outgoing_args_size)
535 #define current_function_arg_offset_rtx (cfun->arg_offset_rtx)
536 #define current_function_stdarg (cfun->stdarg)
537 #define current_function_internal_arg_pointer (cfun->internal_arg_pointer)
538 #define current_function_return_rtx (cfun->return_rtx)
539 #define current_function_instrument_entry_exit (cfun->instrument_entry_exit)
540 #define current_function_profile (cfun->profile)
541 #define current_function_funcdef_no (cfun->funcdef_no)
542 #define current_function_limit_stack (cfun->limit_stack)
543 #define current_function_uses_pic_offset_table (cfun->uses_pic_offset_table)
544 #define current_function_uses_const_pool (cfun->uses_const_pool)
545 #define current_function_cannot_inline (cfun->cannot_inline)
546 #define current_function_epilogue_delay_list (cfun->epilogue_delay_list)
547 #define current_function_has_nonlocal_label (cfun->has_nonlocal_label)
548 #define current_function_has_nonlocal_goto (cfun->has_nonlocal_goto)
550 #define max_parm_reg (cfun->x_max_parm_reg)
551 #define parm_reg_stack_loc (cfun->x_parm_reg_stack_loc)
552 #define cleanup_label (cfun->x_cleanup_label)
553 #define return_label (cfun->x_return_label)
554 #define naked_return_label (cfun->x_naked_return_label)
555 #define save_expr_regs (cfun->x_save_expr_regs)
556 #define stack_slot_list (cfun->x_stack_slot_list)
557 #define parm_birth_insn (cfun->x_parm_birth_insn)
558 #define frame_offset (cfun->x_frame_offset)
559 #define tail_recursion_reentry (cfun->x_tail_recursion_reentry)
560 #define arg_pointer_save_area (cfun->x_arg_pointer_save_area)
561 #define rtl_expr_chain (cfun->x_rtl_expr_chain)
562 #define last_parm_insn (cfun->x_last_parm_insn)
563 #define function_call_count (cfun->x_function_call_count)
564 #define used_temp_slots (cfun->x_used_temp_slots)
565 #define avail_temp_slots (cfun->x_avail_temp_slots)
566 #define temp_slot_level (cfun->x_temp_slot_level)
567 #define target_temp_slot_level (cfun->x_target_temp_slot_level)
568 #define var_temp_slot_level (cfun->x_var_temp_slot_level)
569 #define nonlocal_labels (cfun->x_nonlocal_labels)
570 #define nonlocal_goto_handler_labels (cfun->x_nonlocal_goto_handler_labels)
572 /* Given a function decl for a containing function,
573 return the `struct function' for it. */
574 struct function
*find_function_data (tree
);
576 /* Set NOTE_BLOCK for each block note in the current function. */
577 extern void identify_blocks (void);
579 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
580 and create duplicate blocks. */
581 extern void reorder_blocks (void);
583 /* Set BLOCK_NUMBER for all the blocks in FN. */
584 extern void number_blocks (tree
);
586 extern void clear_block_marks (tree
);
587 extern tree
blocks_nreverse (tree
);
588 extern void reset_block_changes (void);
589 extern void record_block_change (tree
);
590 extern void finalize_block_changes (void);
591 extern void check_block_change (rtx
, tree
*);
592 extern void free_block_changes (void);
594 /* Return size needed for stack frame based on slots so far allocated.
595 This size counts from zero. It is not rounded to STACK_BOUNDARY;
596 the caller may have to do that. */
597 extern HOST_WIDE_INT
get_frame_size (void);
598 /* Likewise, but for a different than the current function. */
599 extern HOST_WIDE_INT
get_func_frame_size (struct function
*);
601 /* A pointer to a function to create target specific, per-function
603 extern struct machine_function
* (*init_machine_status
) (void);
605 /* Save and restore status information for a nested function. */
606 extern void restore_emit_status (struct function
*);
607 extern void free_after_parsing (struct function
*);
608 extern void free_after_compilation (struct function
*);
610 extern void init_varasm_status (struct function
*);
613 extern void diddle_return_value (void (*)(rtx
, void*), void*);
614 extern void clobber_return_register (void);
615 extern void use_return_register (void);
618 extern rtx
get_arg_pointer_save_area (struct function
*);
620 extern void init_virtual_regs (struct emit_status
*);
622 /* Returns the name of the current function. */
623 extern const char *current_function_name (void);
625 /* Called once, at initialization, to initialize function.c. */
626 extern void init_function_once (void);
628 extern void do_warn_unused_parameter (tree
);
630 #endif /* GCC_FUNCTION_H */