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, 2006, 2007, 2008, 2009
4 Free Software Foundation, Inc.
6 This file is part of GCC.
8 GCC is free software; you can redistribute it and/or modify it under
9 the terms of the GNU General Public License as published by the Free
10 Software Foundation; either version 3, or (at your option) any later
13 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
14 WARRANTY; without even the implied warranty of MERCHANTABILITY or
15 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
18 You should have received a copy of the GNU General Public License
19 along with GCC; see the file COPYING3. If not see
20 <http://www.gnu.org/licenses/>. */
22 #ifndef GCC_FUNCTION_H
23 #define GCC_FUNCTION_H
29 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
30 Each element describes one pending sequence.
31 The main insn-chain is saved in the last element of the chain,
32 unless the chain is empty. */
34 struct sequence_stack
GTY(())
36 /* First and last insns in the chain of the saved sequence. */
39 struct sequence_stack
*next
;
42 struct emit_status
GTY(())
44 /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
45 After rtl generation, it is 1 plus the largest register number used. */
48 /* Lowest label number in current function. */
49 int x_first_label_num
;
51 /* The ends of the doubly-linked chain of rtl for the current function.
52 Both are reset to null at the start of rtl generation for the function.
54 start_sequence saves both of these on `sequence_stack' and then starts
55 a new, nested sequence of insns. */
59 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
60 Each element describes one pending sequence.
61 The main insn-chain is saved in the last element of the chain,
62 unless the chain is empty. */
63 struct sequence_stack
*sequence_stack
;
65 /* INSN_UID for next insn emitted.
66 Reset to 1 for each function compiled. */
69 /* Location the last line-number NOTE emitted.
70 This is used to avoid generating duplicates. */
71 location_t x_last_location
;
73 /* The length of the regno_pointer_align, regno_decl, and x_regno_reg_rtx
74 vectors. Since these vectors are needed during the expansion phase when
75 the total number of registers in the function is not yet known, the
76 vectors are copied and made bigger when necessary. */
77 int regno_pointer_align_length
;
79 /* Indexed by pseudo register number, if nonzero gives the known alignment
80 for that pseudo (if REG_POINTER is set in x_regno_reg_rtx).
81 Allocated in parallel with x_regno_reg_rtx. */
82 unsigned char * GTY((skip
)) regno_pointer_align
;
86 /* Indexed by pseudo register number, gives the rtx for that pseudo.
87 Allocated in parallel with regno_pointer_align.
88 FIXME: We could put it into emit_status struct, but gengtype is not able to deal
89 with length attribute nested in top level structures. */
91 extern GTY ((length ("crtl->emit.x_reg_rtx_no"))) rtx
* regno_reg_rtx
;
93 /* For backward compatibility... eventually these should all go away. */
94 #define reg_rtx_no (crtl->emit.x_reg_rtx_no)
95 #define seq_stack (crtl->emit.sequence_stack)
97 #define REGNO_POINTER_ALIGN(REGNO) (crtl->emit.regno_pointer_align[REGNO])
99 struct expr_status
GTY(())
101 /* Number of units that we should eventually pop off the stack.
102 These are the arguments to function calls that have already returned. */
103 int x_pending_stack_adjust
;
105 /* Under some ABIs, it is the caller's responsibility to pop arguments
106 pushed for function calls. A naive implementation would simply pop
107 the arguments immediately after each call. However, if several
108 function calls are made in a row, it is typically cheaper to pop
109 all the arguments after all of the calls are complete since a
110 single pop instruction can be used. Therefore, GCC attempts to
111 defer popping the arguments until absolutely necessary. (For
112 example, at the end of a conditional, the arguments must be popped,
113 since code outside the conditional won't know whether or not the
114 arguments need to be popped.)
116 When INHIBIT_DEFER_POP is nonzero, however, the compiler does not
117 attempt to defer pops. Instead, the stack is popped immediately
118 after each call. Rather then setting this variable directly, use
119 NO_DEFER_POP and OK_DEFER_POP. */
120 int x_inhibit_defer_pop
;
122 /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack
123 boundary can be momentarily unaligned while pushing the arguments.
124 Record the delta since last aligned boundary here in order to get
125 stack alignment in the nested function calls working right. */
126 int x_stack_pointer_delta
;
128 /* Nonzero means __builtin_saveregs has already been done in this function.
129 The value is the pseudoreg containing the value __builtin_saveregs
131 rtx x_saveregs_value
;
133 /* Similarly for __builtin_apply_args. */
134 rtx x_apply_args_value
;
136 /* List of labels that must never be deleted. */
140 typedef struct call_site_record
*call_site_record
;
141 DEF_VEC_P(call_site_record
);
142 DEF_VEC_ALLOC_P(call_site_record
, gc
);
144 /* RTL representation of exception handling. */
145 struct rtl_eh
GTY(())
150 int built_landing_pads
;
159 VEC(tree
,gc
) *ttype_data
;
160 varray_type ehspec_data
;
161 varray_type action_record_data
;
163 VEC(call_site_record
,gc
) *call_site_record
;
166 #define pending_stack_adjust (crtl->expr.x_pending_stack_adjust)
167 #define inhibit_defer_pop (crtl->expr.x_inhibit_defer_pop)
168 #define saveregs_value (crtl->expr.x_saveregs_value)
169 #define apply_args_value (crtl->expr.x_apply_args_value)
170 #define forced_labels (crtl->expr.x_forced_labels)
171 #define stack_pointer_delta (crtl->expr.x_stack_pointer_delta)
175 typedef struct temp_slot
*temp_slot_p
;
176 struct call_site_record
;
178 DEF_VEC_P(temp_slot_p
);
179 DEF_VEC_ALLOC_P(temp_slot_p
,gc
);
181 typedef struct ipa_opt_pass
*ipa_opt_pass
;
183 DEF_VEC_P(ipa_opt_pass
);
184 DEF_VEC_ALLOC_P(ipa_opt_pass
,heap
);
186 enum function_frequency
{
187 /* This function most likely won't be executed at all.
188 (set only when profile feedback is available or via function attribute). */
189 FUNCTION_FREQUENCY_UNLIKELY_EXECUTED
,
190 /* The default value. */
191 FUNCTION_FREQUENCY_NORMAL
,
192 /* Optimize this function hard
193 (set only when profile feedback is available or via function attribute). */
194 FUNCTION_FREQUENCY_HOT
197 struct varasm_status
GTY(())
199 /* If we're using a per-function constant pool, this is it. */
200 struct rtx_constant_pool
*pool
;
202 /* Number of tree-constants deferred during the expansion of this
204 unsigned int deferred_constants
;
207 /* Information mainlined about RTL representation of incoming arguments. */
208 struct incoming_args
GTY(())
210 /* Number of bytes of args popped by function being compiled on its return.
211 Zero if no bytes are to be popped.
212 May affect compilation of return insn or of function epilogue. */
215 /* If function's args have a fixed size, this is that size, in bytes.
217 May affect compilation of return insn or of function epilogue. */
220 /* # bytes the prologue should push and pretend that the caller pushed them.
221 The prologue must do this, but only if parms can be passed in
223 int pretend_args_size
;
225 /* This is the offset from the arg pointer to the place where the first
226 anonymous arg can be found, if there is one. */
229 /* Quantities of various kinds of registers
230 used for the current function's args. */
231 CUMULATIVE_ARGS info
;
233 /* The arg pointer hard register, or the pseudo into which it was copied. */
234 rtx internal_arg_pointer
;
237 /* Data for function partitioning. */
238 struct function_subsections
GTY(())
240 /* Assembly labels for the hot and cold text sections, to
241 be used by debugger functions for determining the size of text
244 const char *hot_section_label
;
245 const char *cold_section_label
;
246 const char *hot_section_end_label
;
247 const char *cold_section_end_label
;
249 /* String to be used for name of cold text sections, via
250 targetm.asm_out.named_section. */
252 const char *unlikely_text_section_name
;
255 /* Datastructures maintained for currently processed function in RTL form. */
256 struct rtl_data
GTY(())
258 struct expr_status expr
;
259 struct emit_status emit
;
260 struct varasm_status varasm
;
261 struct incoming_args args
;
262 struct function_subsections subsections
;
267 /* # of bytes of outgoing arguments. If ACCUMULATE_OUTGOING_ARGS is
268 defined, the needed space is pushed by the prologue. */
269 int outgoing_args_size
;
271 /* If nonzero, an RTL expression for the location at which the current
272 function returns its result. If the current function returns its
273 result in a register, current_function_return_rtx will always be
274 the hard register containing the result. */
277 /* Opaque pointer used by get_hard_reg_initial_val and
278 has_hard_reg_initial_val (see integrate.[hc]). */
279 struct initial_value_struct
*hard_reg_initial_vals
;
281 /* A variable living at the top of the frame that holds a known value.
282 Used for detecting stack clobbers. */
283 tree stack_protect_guard
;
285 /* List (chain of EXPR_LIST) of labels heading the current handlers for
287 rtx x_nonlocal_goto_handler_labels
;
289 /* Label that will go on function epilogue.
290 Jumping to this label serves as a "return" instruction
291 on machines which require execution of the epilogue on all returns. */
294 /* Label that will go on the end of function epilogue.
295 Jumping to this label serves as a "naked return" instruction
296 on machines which require execution of the epilogue on all returns. */
297 rtx x_naked_return_label
;
299 /* List (chain of EXPR_LISTs) of all stack slots in this function.
300 Made for the sake of unshare_all_rtl. */
301 rtx x_stack_slot_list
;
303 /* Place after which to insert the tail_recursion_label if we need one. */
304 rtx x_stack_check_probe_note
;
306 /* Location at which to save the argument pointer if it will need to be
307 referenced. There are two cases where this is done: if nonlocal gotos
308 exist, or if vars stored at an offset from the argument pointer will be
309 needed by inner routines. */
310 rtx x_arg_pointer_save_area
;
312 /* Dynamic Realign Argument Pointer used for realigning stack. */
315 /* Offset to end of allocated area of stack frame.
316 If stack grows down, this is the address of the last stack slot allocated.
317 If stack grows up, this is the address for the next slot. */
318 HOST_WIDE_INT x_frame_offset
;
320 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */
321 rtx x_parm_birth_insn
;
323 /* List of all used temporaries allocated, by level. */
324 VEC(temp_slot_p
,gc
) *x_used_temp_slots
;
326 /* List of available temp slots. */
327 struct temp_slot
*x_avail_temp_slots
;
329 /* Current nesting level for temporaries. */
330 int x_temp_slot_level
;
332 /* The largest alignment needed on the stack, including requirement
333 for outgoing stack alignment. */
334 unsigned int stack_alignment_needed
;
336 /* Preferred alignment of the end of stack frame, which is preferred
337 to call other functions. */
338 unsigned int preferred_stack_boundary
;
340 /* The minimum alignment of parameter stack. */
341 unsigned int parm_stack_boundary
;
343 /* The largest alignment of slot allocated on the stack. */
344 unsigned int max_used_stack_slot_alignment
;
346 /* The stack alignment estimated before reload, with consideration of
348 1. Alignment of local stack variables (max_used_stack_slot_alignment)
349 2. Alignment requirement to call other functions
350 (preferred_stack_boundary)
351 3. Alignment of non-local stack variables but might be spilled in
353 unsigned int stack_alignment_estimated
;
357 /* If some insns can be deferred to the delay slots of the epilogue, the
358 delay list for them is recorded here. */
359 rtx epilogue_delay_list
;
361 /* Nonzero if function being compiled called builtin_return_addr or
362 builtin_frame_address with nonzero count. */
363 bool accesses_prior_frames
;
365 /* Nonzero if the function calls __builtin_eh_return. */
366 bool calls_eh_return
;
368 /* Nonzero if function saves all registers, e.g. if it has a nonlocal
369 label that can reach the exit block via non-exceptional paths. */
370 bool saves_all_registers
;
372 /* Nonzero if function being compiled has nonlocal gotos to parent
374 bool has_nonlocal_goto
;
376 /* Nonzero if function being compiled has an asm statement. */
377 bool has_asm_statement
;
379 /* This bit is used by the exception handling logic. It is set if all
380 calls (if any) are sibling calls. Such functions do not have to
381 have EH tables generated, as they cannot throw. A call to such a
382 function, however, should be treated as throwing if any of its callees
384 bool all_throwers_are_sibcalls
;
386 /* Nonzero if stack limit checking should be enabled in the current
390 /* Nonzero if profiling code should be generated. */
393 /* Nonzero if the current function uses the constant pool. */
394 bool uses_const_pool
;
396 /* Nonzero if the current function uses pic_offset_table_rtx. */
397 bool uses_pic_offset_table
;
399 /* Nonzero if the current function needs an lsda for exception handling. */
402 /* Set when the tail call has been produced. */
405 /* Nonzero if code to initialize arg_pointer_save_area has been emitted. */
406 bool arg_pointer_save_area_init
;
408 /* Nonzero if current function must be given a frame pointer.
409 Set in global.c if anything is allocated on the stack there. */
410 bool frame_pointer_needed
;
412 /* When set, expand should optimize for speed. */
413 bool maybe_hot_insn_p
;
415 /* Nonzero if function stack realignment is needed. This flag may be
416 set twice: before and after reload. It is set before reload wrt
417 stack alignment estimation before reload. It will be changed after
418 reload if by then criteria of stack realignment is different.
419 The value set after reload is the accurate one and is finalized. */
420 bool stack_realign_needed
;
422 /* Nonzero if function stack realignment is tried. This flag is set
423 only once before reload. It affects register elimination. This
424 is used to generate DWARF debug info for stack variables. */
425 bool stack_realign_tried
;
427 /* Nonzero if function being compiled needs dynamic realigned
428 argument pointer (drap) if stack needs realigning. */
431 /* Nonzero if function stack realignment estimation is done, namely
432 stack_realign_needed flag has been set before reload wrt estimated
433 stack alignment info. */
434 bool stack_realign_processed
;
436 /* Nonzero if function stack realignment has been finalized, namely
437 stack_realign_needed flag has been set and finalized after reload. */
438 bool stack_realign_finalized
;
440 /* True if dbr_schedule has already been called for this function. */
441 bool dbr_scheduled_p
;
443 /* True if current function can not throw. Unlike
444 TREE_NOTHROW (current_function_decl) it is set even for overwritable
445 function where currently compiled version of it is nothrow. */
449 #define return_label (crtl->x_return_label)
450 #define naked_return_label (crtl->x_naked_return_label)
451 #define stack_slot_list (crtl->x_stack_slot_list)
452 #define parm_birth_insn (crtl->x_parm_birth_insn)
453 #define frame_offset (crtl->x_frame_offset)
454 #define stack_check_probe_note (crtl->x_stack_check_probe_note)
455 #define arg_pointer_save_area (crtl->x_arg_pointer_save_area)
456 #define used_temp_slots (crtl->x_used_temp_slots)
457 #define avail_temp_slots (crtl->x_avail_temp_slots)
458 #define temp_slot_level (crtl->x_temp_slot_level)
459 #define nonlocal_goto_handler_labels (crtl->x_nonlocal_goto_handler_labels)
460 #define frame_pointer_needed (crtl->frame_pointer_needed)
461 #define stack_realign_fp (crtl->stack_realign_needed && !crtl->need_drap)
462 #define stack_realign_drap (crtl->stack_realign_needed && crtl->need_drap)
464 extern GTY(()) struct rtl_data x_rtl
;
466 /* Accessor to RTL datastructures. We keep them statically allocated now since
467 we never keep multiple functions. For threaded compiler we might however
468 want to do differently. */
469 #define crtl (&x_rtl)
471 /* This structure can save all the important global and static variables
472 describing the status of the current function. */
474 struct function
GTY(())
476 struct eh_status
*eh
;
478 /* The control flow graph for this function. */
479 struct control_flow_graph
*cfg
;
481 /* GIMPLE body for this function. */
482 struct gimple_seq_d
*gimple_body
;
484 /* SSA and dataflow information. */
485 struct gimple_df
*gimple_df
;
487 /* The loops in this function. */
488 struct loops
*x_current_loops
;
490 /* Value histograms attached to particular statements. */
491 htab_t
GTY((skip
)) value_histograms
;
493 /* For function.c. */
495 /* Points to the FUNCTION_DECL of this function. */
498 /* A PARM_DECL that should contain the static chain for this function.
499 It will be initialized at the beginning of the function. */
500 tree static_chain_decl
;
502 /* An expression that contains the non-local goto save area. The first
503 word is the saved frame pointer and the second is the saved stack
505 tree nonlocal_goto_save_area
;
507 /* List of function local variables, functions, types and constants. */
512 /* tm.h can use this to store whatever it likes. */
513 struct machine_function
* GTY ((maybe_undef
)) machine
;
515 /* Language-specific code can use this to store whatever it likes. */
516 struct language_function
* language
;
518 /* Used types hash table. */
519 htab_t
GTY ((param_is (union tree_node
))) used_types_hash
;
521 /* Last statement uid. */
524 /* Function sequence number for profiling, debugging, etc. */
527 /* Line number of the start of the function for debugging purposes. */
528 location_t function_start_locus
;
530 /* Line number of the end of the function. */
531 location_t function_end_locus
;
533 /* Properties used by the pass manager. */
534 unsigned int curr_properties
;
535 unsigned int last_verified
;
536 /* Interprocedural passes scheduled to have their transform functions
537 applied next time we execute local pass on them. We maintain it
538 per-function in order to allow IPA passes to introduce new functions. */
539 VEC(ipa_opt_pass
,heap
) * GTY((skip
)) ipa_transforms_to_apply
;
541 /* Collected bit flags. */
543 /* Number of units of general registers that need saving in stdarg
544 function. What unit is depends on the backend, either it is number
545 of bytes, or it can be number of registers. */
546 unsigned int va_list_gpr_size
: 8;
548 /* Number of units of floating point registers that need saving in stdarg
550 unsigned int va_list_fpr_size
: 8;
553 /* How commonly executed the function is. Initialized during branch
554 probabilities pass. */
555 ENUM_BITFIELD (function_frequency
) function_frequency
: 2;
557 /* Nonzero if function being compiled can call setjmp. */
558 unsigned int calls_setjmp
: 1;
560 /* Nonzero if function being compiled can call alloca,
561 either as a subroutine or builtin. */
562 unsigned int calls_alloca
: 1;
564 /* Nonzero if function being compiled receives nonlocal gotos
565 from nested functions. */
566 unsigned int has_nonlocal_label
: 1;
568 /* Nonzero if current function uses stdarg.h or equivalent. */
569 unsigned int stdarg
: 1;
571 /* Nonzero if the back-end should not keep track of expressions that
572 determine the size of variable-sized objects. Normally, such
573 expressions are saved away, and then expanded when the next
574 function is started. For example, if a parameter has a
575 variable-sized type, then the size of the parameter is computed
576 when the function body is entered. However, some front-ends do
577 not desire this behavior. */
578 unsigned int dont_save_pending_sizes_p
: 1;
580 unsigned int after_inlining
: 1;
581 unsigned int always_inline_functions_inlined
: 1;
583 /* Fields below this point are not set for abstract functions; see
584 allocate_struct_function. */
586 /* Nonzero if function being compiled needs to be given an address
587 where the value should be stored. */
588 unsigned int returns_struct
: 1;
590 /* Nonzero if function being compiled needs to
591 return the address of where it has put a structure value. */
592 unsigned int returns_pcc_struct
: 1;
594 /* Nonzero if pass_tree_profile was run on this function. */
595 unsigned int after_tree_profile
: 1;
597 /* Nonzero if this function has local DECL_HARD_REGISTER variables.
598 In this case code motion has to be done more carefully. */
599 unsigned int has_local_explicit_reg_vars
: 1;
601 /* Nonzero if the current function is a thunk, i.e., a lightweight
602 function implemented by the output_mi_thunk hook) that just
603 adjusts one of its arguments and forwards to another
605 unsigned int is_thunk
: 1;
608 /* If va_list_[gf]pr_size is set to this, it means we don't know how
609 many units need to be saved. */
610 #define VA_LIST_MAX_GPR_SIZE 255
611 #define VA_LIST_MAX_FPR_SIZE 255
613 /* The function currently being compiled. */
614 extern GTY(()) struct function
*cfun
;
616 /* In order to ensure that cfun is not set directly, we redefine it so
617 that it is not an lvalue. Rather than assign to cfun, use
618 push_cfun or set_cfun. */
619 #define cfun (cfun + 0)
621 /* Nonzero if we've already converted virtual regs to hard regs. */
622 extern int virtuals_instantiated
;
624 /* Nonzero if at least one trampoline has been created. */
625 extern int trampolines_created
;
627 /* cfun shouldn't be set directly; use one of these functions instead. */
628 extern void set_cfun (struct function
*new_cfun
);
629 extern void push_cfun (struct function
*new_cfun
);
630 extern void pop_cfun (void);
631 extern void instantiate_decl_rtl (rtx x
);
633 /* For backward compatibility... eventually these should all go away. */
634 #define current_function_funcdef_no (cfun->funcdef_no)
636 #define current_loops (cfun->x_current_loops)
637 #define dom_computed (cfun->cfg->x_dom_computed)
638 #define n_bbs_in_dom_tree (cfun->cfg->x_n_bbs_in_dom_tree)
639 #define VALUE_HISTOGRAMS(fun) (fun)->value_histograms
641 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
642 and create duplicate blocks. */
643 extern void reorder_blocks (void);
645 /* Set BLOCK_NUMBER for all the blocks in FN. */
646 extern void number_blocks (tree
);
648 extern void clear_block_marks (tree
);
649 extern tree
blocks_nreverse (tree
);
651 /* Return size needed for stack frame based on slots so far allocated.
652 This size counts from zero. It is not rounded to STACK_BOUNDARY;
653 the caller may have to do that. */
654 extern HOST_WIDE_INT
get_frame_size (void);
656 /* Issue an error message and return TRUE if frame OFFSET overflows in
657 the signed target pointer arithmetics for function FUNC. Otherwise
659 extern bool frame_offset_overflow (HOST_WIDE_INT
, tree
);
661 /* A pointer to a function to create target specific, per-function
663 extern struct machine_function
* (*init_machine_status
) (void);
665 /* Save and restore status information for a nested function. */
666 extern void free_after_parsing (struct function
*);
667 extern void free_after_compilation (struct function
*);
669 extern void init_varasm_status (void);
672 extern void diddle_return_value (void (*)(rtx
, void*), void*);
673 extern void clobber_return_register (void);
676 extern rtx
get_arg_pointer_save_area (void);
678 /* Returns the name of the current function. */
679 extern const char *current_function_name (void);
681 extern void do_warn_unused_parameter (tree
);
683 extern bool pass_by_reference (CUMULATIVE_ARGS
*, enum machine_mode
,
685 extern bool reference_callee_copied (CUMULATIVE_ARGS
*, enum machine_mode
,
688 extern void used_types_insert (tree
);
690 extern int get_next_funcdef_no (void);
691 #endif /* GCC_FUNCTION_H */