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 /* Opaque pointer used by get_hard_reg_initial_val and
236 has_hard_reg_initial_val (see integrate.[hc]). */
237 struct initial_value_struct
*hard_reg_initial_vals
;
239 /* Number of function calls seen so far in current function. */
240 int x_function_call_count
;
242 /* List (chain of EXPR_LIST) of labels heading the current handlers for
244 rtx x_nonlocal_goto_handler_labels
;
246 /* Label that will go on parm cleanup code, if any.
247 Jumping to this label runs cleanup code for parameters, if
248 such code must be run. Following this code is the logical return
252 /* Label that will go on function epilogue.
253 Jumping to this label serves as a "return" instruction
254 on machines which require execution of the epilogue on all returns. */
257 /* Label that will go on the end of function epilogue.
258 Jumping to this label serves as a "naked return" instruction
259 on machines which require execution of the epilogue on all returns. */
260 rtx x_naked_return_label
;
262 /* Label and register for unswitching computed gotos. */
263 rtx computed_goto_common_label
;
264 rtx computed_goto_common_reg
;
266 /* List (chain of EXPR_LISTs) of pseudo-regs of SAVE_EXPRs.
267 So we can mark them all live at the end of the function, if nonopt. */
268 rtx x_save_expr_regs
;
270 /* List (chain of EXPR_LISTs) of all stack slots in this function.
271 Made for the sake of unshare_all_rtl. */
272 rtx x_stack_slot_list
;
274 /* Chain of all RTL_EXPRs that have insns in them. */
275 tree x_rtl_expr_chain
;
277 /* Place after which to insert the tail_recursion_label if we need one. */
278 rtx x_tail_recursion_reentry
;
280 /* Location at which to save the argument pointer if it will need to be
281 referenced. There are two cases where this is done: if nonlocal gotos
282 exist, or if vars stored at an offset from the argument pointer will be
283 needed by inner routines. */
284 rtx x_arg_pointer_save_area
;
286 /* Offset to end of allocated area of stack frame.
287 If stack grows down, this is the address of the last stack slot allocated.
288 If stack grows up, this is the address for the next slot. */
289 HOST_WIDE_INT x_frame_offset
;
291 /* A VAR_DECL that should contain the static chain for this function.
292 It will be initialized at the beginning of the function. */
293 tree static_chain_decl
;
295 /* An expression that contains the non-local goto save area. The first
296 word is the saved frame pointer and the second is the saved stack
298 tree nonlocal_goto_save_area
;
300 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */
301 rtx x_parm_birth_insn
;
303 /* Last insn of those whose job was to put parms into their nominal
305 rtx x_last_parm_insn
;
307 /* 1 + last pseudo register number possibly used for loading a copy
308 of a parameter of this function. */
309 unsigned int x_max_parm_reg
;
311 /* Vector indexed by REGNO, containing location on stack in which
312 to put the parm which is nominally in pseudo register REGNO,
313 if we discover that that parm must go in the stack. The highest
314 element in this vector is one less than MAX_PARM_REG, above. */
315 rtx
* GTY ((length ("%h.x_max_parm_reg"))) x_parm_reg_stack_loc
;
317 /* List of all used temporaries allocated, by level. */
318 struct varray_head_tag
* GTY((param_is (struct temp_slot
))) x_used_temp_slots
;
320 /* List of available temp slots. */
321 struct temp_slot
*x_avail_temp_slots
;
323 /* Current nesting level for temporaries. */
324 int x_temp_slot_level
;
326 /* Current nesting level for variables in a block. */
327 int x_var_temp_slot_level
;
329 /* When temporaries are created by TARGET_EXPRs, they are created at
330 this level of temp_slot_level, so that they can remain allocated
331 until no longer needed. CLEANUP_POINT_EXPRs define the lifetime
333 int x_target_temp_slot_level
;
335 /* This slot is initialized as 0 and is added to
336 during the nested function. */
337 struct var_refs_queue
*fixup_var_refs_queue
;
339 /* For integrate.c. */
341 int no_debugging_symbols
;
342 rtvec original_arg_vector
;
343 tree original_decl_initial
;
344 /* Last insn of those whose job was to put parms into their nominal
346 rtx inl_last_parm_insn
;
347 /* Highest label number in current function. */
348 int inl_max_label_num
;
350 /* Function sequence number for profiling, debugging, etc. */
355 /* tm.h can use this to store whatever it likes. */
356 struct machine_function
* GTY ((maybe_undef
)) machine
;
357 /* The largest alignment of slot allocated on the stack. */
358 int stack_alignment_needed
;
359 /* Preferred alignment of the end of stack frame. */
360 int preferred_stack_boundary
;
361 /* Set when the call to function itself has been emit. */
362 bool recursive_call_emit
;
363 /* Set when the tail call has been produced. */
366 /* Language-specific code can use this to store whatever it likes. */
367 struct language_function
* language
;
371 /* If some insns can be deferred to the delay slots of the epilogue, the
372 delay list for them is recorded here. */
373 rtx epilogue_delay_list
;
375 /* Nonzero if NOTE_INSN_BLOCK_BEG / NOTE_INSN_BLOCK_END notes should not
377 unsigned int dont_emit_block_notes
: 1;
379 /* How commonly executed the function is. Initialized during branch
380 probabilities pass. */
381 enum function_frequency
{
382 /* This function most likely won't be executed at all.
383 (set only when profile feedback is available). */
384 FUNCTION_FREQUENCY_UNLIKELY_EXECUTED
,
385 /* The default value. */
386 FUNCTION_FREQUENCY_NORMAL
,
387 /* Optimize this function hard
388 (set only when profile feedback is available). */
389 FUNCTION_FREQUENCY_HOT
390 } function_frequency
;
392 /* Maximal number of entities in the single jumptable. Used to estimate
393 final flowgraph size. */
394 int max_jumptable_ents
;
396 /* UIDs for LABEL_DECLs. */
399 /* Line number of the end of the function. */
400 location_t function_end_locus
;
402 /* Array mapping insn uids to blocks. */
403 struct varray_head_tag
*ib_boundaries_block
;
405 /* The variables unexpanded so far. */
406 tree unexpanded_var_list
;
408 /* Collected bit flags. */
410 /* Nonzero if function being compiled needs to be given an address
411 where the value should be stored. */
412 unsigned int returns_struct
: 1;
414 /* Nonzero if function being compiled needs to
415 return the address of where it has put a structure value. */
416 unsigned int returns_pcc_struct
: 1;
418 /* Nonzero if the current function returns a pointer type. */
419 unsigned int returns_pointer
: 1;
421 /* Nonzero if function being compiled can call setjmp. */
422 unsigned int calls_setjmp
: 1;
424 /* Nonzero if function being compiled can call longjmp. */
425 unsigned int calls_longjmp
: 1;
427 /* Nonzero if function being compiled can call alloca,
428 either as a subroutine or builtin. */
429 unsigned int calls_alloca
: 1;
431 /* Nonzero if the function calls __builtin_eh_return. */
432 unsigned int calls_eh_return
: 1;
434 /* Nonzero if function being compiled receives nonlocal gotos
435 from nested functions. */
436 unsigned int has_nonlocal_label
: 1;
438 /* Nonzero if function being compiled has nonlocal gotos to parent
440 unsigned int has_nonlocal_goto
: 1;
442 /* Nonzero if function being compiled contains nested functions. */
443 unsigned int contains_functions
: 1;
445 /* Nonzero if the function being compiled issues a computed jump. */
446 unsigned int has_computed_jump
: 1;
448 /* Nonzero if the current function is a thunk, i.e., a lightweight
449 function implemented by the output_mi_thunk hook) that just
450 adjusts one of its arguments and forwards to another
452 unsigned int is_thunk
: 1;
454 /* This bit is used by the exception handling logic. It is set if all
455 calls (if any) are sibling calls. Such functions do not have to
456 have EH tables generated, as they cannot throw. A call to such a
457 function, however, should be treated as throwing if any of its callees
459 unsigned int all_throwers_are_sibcalls
: 1;
461 /* Nonzero if instrumentation calls for function entry and exit should be
463 unsigned int instrument_entry_exit
: 1;
465 /* Nonzero if profiling code should be generated. */
466 unsigned int profile
: 1;
468 /* Nonzero if stack limit checking should be enabled in the current
470 unsigned int limit_stack
: 1;
472 /* Nonzero if current function uses stdarg.h or equivalent. */
473 unsigned int stdarg
: 1;
475 /* Nonzero if this function is being processed in function-at-a-time
476 mode. In other words, if all tree structure for this function,
477 including the BLOCK tree, is created before RTL generation
479 unsigned int x_whole_function_mode_p
: 1;
481 /* Nonzero if the back-end should not keep track of expressions that
482 determine the size of variable-sized objects. Normally, such
483 expressions are saved away, and then expanded when the next
484 function is started. For example, if a parameter has a
485 variable-sized type, then the size of the parameter is computed
486 when the function body is entered. However, some front-ends do
487 not desire this behavior. */
488 unsigned int x_dont_save_pending_sizes_p
: 1;
490 /* Nonzero if the current function uses the constant pool. */
491 unsigned int uses_const_pool
: 1;
493 /* Nonzero if the current function uses pic_offset_table_rtx. */
494 unsigned int uses_pic_offset_table
: 1;
496 /* Nonzero if the current function needs an lsda for exception handling. */
497 unsigned int uses_eh_lsda
: 1;
499 /* Nonzero if code to initialize arg_pointer_save_area has been emitted. */
500 unsigned int arg_pointer_save_area_init
: 1;
503 /* The function currently being compiled. */
504 extern GTY(()) struct function
*cfun
;
506 /* Pointer to chain of `struct function' for containing functions. */
507 extern GTY(()) struct function
*outer_function_chain
;
509 /* Nonzero if we've already converted virtual regs to hard regs. */
510 extern int virtuals_instantiated
;
512 /* Nonzero if at least one trampoline has been created. */
513 extern int trampolines_created
;
515 /* For backward compatibility... eventually these should all go away. */
516 #define current_function_pops_args (cfun->pops_args)
517 #define current_function_returns_struct (cfun->returns_struct)
518 #define current_function_returns_pcc_struct (cfun->returns_pcc_struct)
519 #define current_function_returns_pointer (cfun->returns_pointer)
520 #define current_function_calls_setjmp (cfun->calls_setjmp)
521 #define current_function_calls_alloca (cfun->calls_alloca)
522 #define current_function_calls_longjmp (cfun->calls_longjmp)
523 #define current_function_calls_eh_return (cfun->calls_eh_return)
524 #define current_function_has_computed_jump (cfun->has_computed_jump)
525 #define current_function_contains_functions (cfun->contains_functions)
526 #define current_function_is_thunk (cfun->is_thunk)
527 #define current_function_args_info (cfun->args_info)
528 #define current_function_args_size (cfun->args_size)
529 #define current_function_pretend_args_size (cfun->pretend_args_size)
530 #define current_function_outgoing_args_size (cfun->outgoing_args_size)
531 #define current_function_arg_offset_rtx (cfun->arg_offset_rtx)
532 #define current_function_stdarg (cfun->stdarg)
533 #define current_function_internal_arg_pointer (cfun->internal_arg_pointer)
534 #define current_function_return_rtx (cfun->return_rtx)
535 #define current_function_instrument_entry_exit (cfun->instrument_entry_exit)
536 #define current_function_profile (cfun->profile)
537 #define current_function_funcdef_no (cfun->funcdef_no)
538 #define current_function_limit_stack (cfun->limit_stack)
539 #define current_function_uses_pic_offset_table (cfun->uses_pic_offset_table)
540 #define current_function_uses_const_pool (cfun->uses_const_pool)
541 #define current_function_epilogue_delay_list (cfun->epilogue_delay_list)
542 #define current_function_has_nonlocal_label (cfun->has_nonlocal_label)
543 #define current_function_has_nonlocal_goto (cfun->has_nonlocal_goto)
545 #define max_parm_reg (cfun->x_max_parm_reg)
546 #define parm_reg_stack_loc (cfun->x_parm_reg_stack_loc)
547 #define cleanup_label (cfun->x_cleanup_label)
548 #define return_label (cfun->x_return_label)
549 #define naked_return_label (cfun->x_naked_return_label)
550 #define save_expr_regs (cfun->x_save_expr_regs)
551 #define stack_slot_list (cfun->x_stack_slot_list)
552 #define parm_birth_insn (cfun->x_parm_birth_insn)
553 #define frame_offset (cfun->x_frame_offset)
554 #define tail_recursion_reentry (cfun->x_tail_recursion_reentry)
555 #define arg_pointer_save_area (cfun->x_arg_pointer_save_area)
556 #define rtl_expr_chain (cfun->x_rtl_expr_chain)
557 #define last_parm_insn (cfun->x_last_parm_insn)
558 #define function_call_count (cfun->x_function_call_count)
559 #define used_temp_slots (cfun->x_used_temp_slots)
560 #define avail_temp_slots (cfun->x_avail_temp_slots)
561 #define temp_slot_level (cfun->x_temp_slot_level)
562 #define target_temp_slot_level (cfun->x_target_temp_slot_level)
563 #define var_temp_slot_level (cfun->x_var_temp_slot_level)
564 #define nonlocal_labels (cfun->x_nonlocal_labels)
565 #define nonlocal_goto_handler_labels (cfun->x_nonlocal_goto_handler_labels)
567 /* Given a function decl for a containing function,
568 return the `struct function' for it. */
569 struct function
*find_function_data (tree
);
571 /* Set NOTE_BLOCK for each block note in the current function. */
572 extern void identify_blocks (void);
574 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
575 and create duplicate blocks. */
576 extern void reorder_blocks (void);
578 /* Set BLOCK_NUMBER for all the blocks in FN. */
579 extern void number_blocks (tree
);
581 extern void clear_block_marks (tree
);
582 extern tree
blocks_nreverse (tree
);
583 extern void reset_block_changes (void);
584 extern void record_block_change (tree
);
585 extern void finalize_block_changes (void);
586 extern void check_block_change (rtx
, tree
*);
587 extern void free_block_changes (void);
589 /* Return size needed for stack frame based on slots so far allocated.
590 This size counts from zero. It is not rounded to STACK_BOUNDARY;
591 the caller may have to do that. */
592 extern HOST_WIDE_INT
get_frame_size (void);
593 /* Likewise, but for a different than the current function. */
594 extern HOST_WIDE_INT
get_func_frame_size (struct function
*);
596 /* A pointer to a function to create target specific, per-function
598 extern struct machine_function
* (*init_machine_status
) (void);
600 /* Save and restore status information for a nested function. */
601 extern void restore_emit_status (struct function
*);
602 extern void free_after_parsing (struct function
*);
603 extern void free_after_compilation (struct function
*);
605 extern void init_varasm_status (struct function
*);
608 extern void diddle_return_value (void (*)(rtx
, void*), void*);
609 extern void clobber_return_register (void);
610 extern void use_return_register (void);
613 extern rtx
get_arg_pointer_save_area (struct function
*);
615 extern void init_virtual_regs (struct emit_status
*);
616 extern void instantiate_virtual_regs (void);
618 /* Returns the name of the current function. */
619 extern const char *current_function_name (void);
621 /* Called once, at initialization, to initialize function.c. */
622 extern void init_function_once (void);
624 extern void do_warn_unused_parameter (tree
);
626 #endif /* GCC_FUNCTION_H */