1 /* Structure for saving state for a nested function.
2 Copyright (C) 1989, 1992, 1993, 1994, 1995, 1996, 1997, 1998,
3 1999, 2000 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 struct var_refs_queue
GTY(())
25 enum machine_mode promoted_mode
;
27 struct var_refs_queue
*next
;
30 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
31 Each element describes one pending sequence.
32 The main insn-chain is saved in the last element of the chain,
33 unless the chain is empty. */
35 struct sequence_stack
GTY(())
37 /* First and last insns in the chain of the saved sequence. */
40 tree sequence_rtl_expr
;
41 struct sequence_stack
*next
;
44 extern struct sequence_stack
*sequence_stack
;
46 /* Stack of single obstacks. */
48 struct simple_obstack_stack
50 struct obstack
*obstack
;
51 struct simple_obstack_stack
*next
;
54 struct emit_status
GTY(())
56 /* This is reset to LAST_VIRTUAL_REGISTER + 1 at the start of each function.
57 After rtl generation, it is 1 plus the largest register number used. */
60 /* Lowest label number in current function. */
61 int x_first_label_num
;
63 /* The ends of the doubly-linked chain of rtl for the current function.
64 Both are reset to null at the start of rtl generation for the function.
66 start_sequence saves both of these on `sequence_stack' along with
67 `sequence_rtl_expr' and then starts a new, nested sequence of insns. */
71 /* RTL_EXPR within which the current sequence will be placed. Use to
72 prevent reuse of any temporaries within the sequence until after the
73 RTL_EXPR is emitted. */
74 tree sequence_rtl_expr
;
76 /* Stack of pending (incomplete) sequences saved by `start_sequence'.
77 Each element describes one pending sequence.
78 The main insn-chain is saved in the last element of the chain,
79 unless the chain is empty. */
80 struct sequence_stack
*sequence_stack
;
82 /* INSN_UID for next insn emitted.
83 Reset to 1 for each function compiled. */
86 /* Location the last line-number NOTE emitted.
87 This is used to avoid generating duplicates. */
88 location_t x_last_location
;
90 /* The length of the regno_pointer_align, regno_decl, and x_regno_reg_rtx
91 vectors. Since these vectors are needed during the expansion phase when
92 the total number of registers in the function is not yet known, the
93 vectors are copied and made bigger when necessary. */
94 int regno_pointer_align_length
;
96 /* Indexed by pseudo register number, if nonzero gives the known alignment
97 for that pseudo (if REG_POINTER is set in x_regno_reg_rtx).
98 Allocated in parallel with x_regno_reg_rtx. */
99 unsigned char * GTY ((length ("%h.x_reg_rtx_no")))
102 /* Indexed by pseudo register number, gives the rtx for that pseudo.
103 Allocated in parallel with regno_pointer_align.
105 Note MEM expressions can appear in this array due to the actions
106 of put_var_into_stack. */
107 rtx
* GTY ((length ("%h.x_reg_rtx_no"))) x_regno_reg_rtx
;
110 /* For backward compatibility... eventually these should all go away. */
111 #define reg_rtx_no (cfun->emit->x_reg_rtx_no)
112 #define seq_rtl_expr (cfun->emit->sequence_rtl_expr)
113 #define regno_reg_rtx (cfun->emit->x_regno_reg_rtx)
114 #define seq_stack (cfun->emit->sequence_stack)
116 #define REGNO_POINTER_ALIGN(REGNO) (cfun->emit->regno_pointer_align[REGNO])
118 struct expr_status
GTY(())
120 /* Number of units that we should eventually pop off the stack.
121 These are the arguments to function calls that have already returned. */
122 int x_pending_stack_adjust
;
124 /* Under some ABIs, it is the caller's responsibility to pop arguments
125 pushed for function calls. A naive implementation would simply pop
126 the arguments immediately after each call. However, if several
127 function calls are made in a row, it is typically cheaper to pop
128 all the arguments after all of the calls are complete since a
129 single pop instruction can be used. Therefore, GCC attempts to
130 defer popping the arguments until absolutely necessary. (For
131 example, at the end of a conditional, the arguments must be popped,
132 since code outside the conditional won't know whether or not the
133 arguments need to be popped.)
135 When INHIBIT_DEFER_POP is nonzero, however, the compiler does not
136 attempt to defer pops. Instead, the stack is popped immediately
137 after each call. Rather then setting this variable directly, use
138 NO_DEFER_POP and OK_DEFER_POP. */
139 int x_inhibit_defer_pop
;
141 /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack
142 boundary can be momentarily unaligned while pushing the arguments.
143 Record the delta since last aligned boundary here in order to get
144 stack alignment in the nested function calls working right. */
145 int x_stack_pointer_delta
;
147 /* Nonzero means __builtin_saveregs has already been done in this function.
148 The value is the pseudoreg containing the value __builtin_saveregs
150 rtx x_saveregs_value
;
152 /* Similarly for __builtin_apply_args. */
153 rtx x_apply_args_value
;
155 /* List of labels that must never be deleted. */
158 /* Postincrements that still need to be expanded. */
162 #define pending_stack_adjust (cfun->expr->x_pending_stack_adjust)
163 #define inhibit_defer_pop (cfun->expr->x_inhibit_defer_pop)
164 #define saveregs_value (cfun->expr->x_saveregs_value)
165 #define apply_args_value (cfun->expr->x_apply_args_value)
166 #define forced_labels (cfun->expr->x_forced_labels)
167 #define pending_chain (cfun->expr->x_pending_chain)
168 #define stack_pointer_delta (cfun->expr->x_stack_pointer_delta)
170 /* This structure can save all the important global and static variables
171 describing the status of the current function. */
173 struct function
GTY(())
175 struct eh_status
*eh
;
176 struct stmt_status
*stmt
;
177 struct expr_status
*expr
;
178 struct emit_status
*emit
;
179 struct varasm_status
*varasm
;
181 /* For function.c. */
183 /* Name of this function. */
186 /* Points to the FUNCTION_DECL of this function. */
189 /* Function containing this function, if any. */
190 struct function
*outer
;
192 /* Number of bytes of args popped by function being compiled on its return.
193 Zero if no bytes are to be popped.
194 May affect compilation of return insn or of function epilogue. */
197 /* If function's args have a fixed size, this is that size, in bytes.
199 May affect compilation of return insn or of function epilogue. */
202 /* # bytes the prologue should push and pretend that the caller pushed them.
203 The prologue must do this, but only if parms can be passed in
205 int pretend_args_size
;
207 /* # of bytes of outgoing arguments. If ACCUMULATE_OUTGOING_ARGS is
208 defined, the needed space is pushed by the prologue. */
209 int outgoing_args_size
;
211 /* This is the offset from the arg pointer to the place where the first
212 anonymous arg can be found, if there is one. */
215 /* Quantities of various kinds of registers
216 used for the current function's args. */
217 CUMULATIVE_ARGS args_info
;
219 /* If nonzero, an RTL expression for the location at which the current
220 function returns its result. If the current function returns its
221 result in a register, current_function_return_rtx will always be
222 the hard register containing the result. */
225 /* The arg pointer hard register, or the pseudo into which it was copied. */
226 rtx internal_arg_pointer
;
228 /* Language-specific reason why the current function cannot be made
230 const char *cannot_inline
;
232 /* Opaque pointer used by get_hard_reg_initial_val and
233 has_hard_reg_initial_val (see integrate.[hc]). */
234 struct initial_value_struct
*hard_reg_initial_vals
;
236 /* Number of function calls seen so far in current function. */
237 int x_function_call_count
;
239 /* List (chain of TREE_LIST) of LABEL_DECLs for all nonlocal labels
240 (labels to which there can be nonlocal gotos from nested functions)
242 tree x_nonlocal_labels
;
244 /* List (chain of EXPR_LIST) of stack slots that hold the current handlers
245 for nonlocal gotos. There is one for every nonlocal label in the
246 function; this list matches the one in nonlocal_labels.
247 Zero when function does not have nonlocal labels. */
248 rtx x_nonlocal_goto_handler_slots
;
250 /* List (chain of EXPR_LIST) of labels heading the current handlers for
252 rtx x_nonlocal_goto_handler_labels
;
254 /* RTX for stack slot that holds the stack pointer value to restore
256 Zero when function does not have nonlocal labels. */
257 rtx x_nonlocal_goto_stack_level
;
259 /* Label that will go on parm cleanup code, if any.
260 Jumping to this label runs cleanup code for parameters, if
261 such code must be run. Following this code is the logical return
265 /* Label that will go on function epilogue.
266 Jumping to this label serves as a "return" instruction
267 on machines which require execution of the epilogue on all returns. */
270 /* Label and register for unswitching computed gotos. */
271 rtx computed_goto_common_label
;
272 rtx computed_goto_common_reg
;
274 /* List (chain of EXPR_LISTs) of pseudo-regs of SAVE_EXPRs.
275 So we can mark them all live at the end of the function, if nonopt. */
276 rtx x_save_expr_regs
;
278 /* List (chain of EXPR_LISTs) of all stack slots in this function.
279 Made for the sake of unshare_all_rtl. */
280 rtx x_stack_slot_list
;
282 /* Chain of all RTL_EXPRs that have insns in them. */
283 tree x_rtl_expr_chain
;
285 /* Label to jump back to for tail recursion, or 0 if we have
286 not yet needed one for this function. */
287 rtx x_tail_recursion_label
;
289 /* Place after which to insert the tail_recursion_label if we need one. */
290 rtx x_tail_recursion_reentry
;
292 /* Location at which to save the argument pointer if it will need to be
293 referenced. There are two cases where this is done: if nonlocal gotos
294 exist, or if vars stored at an offset from the argument pointer will be
295 needed by inner routines. */
296 rtx x_arg_pointer_save_area
;
298 /* If the function returns non-void, we will emit a clobber of the
299 return registers just in case the user fell off the end without
300 returning a proper value. This is that insn. */
301 rtx x_clobber_return_insn
;
303 /* Offset to end of allocated area of stack frame.
304 If stack grows down, this is the address of the last stack slot allocated.
305 If stack grows up, this is the address for the next slot. */
306 HOST_WIDE_INT x_frame_offset
;
308 /* List (chain of TREE_LISTs) of static chains for containing functions.
309 Each link has a FUNCTION_DECL in the TREE_PURPOSE and a reg rtx
310 in an RTL_EXPR in the TREE_VALUE. */
311 tree x_context_display
;
313 /* List (chain of TREE_LISTs) of trampolines for nested functions.
314 The trampoline sets up the static chain and jumps to the function.
315 We supply the trampoline's address when the function's address is
318 Each link has a FUNCTION_DECL in the TREE_PURPOSE and a reg rtx
319 in an RTL_EXPR in the TREE_VALUE. */
320 tree x_trampoline_list
;
322 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */
323 rtx x_parm_birth_insn
;
325 /* Last insn of those whose job was to put parms into their nominal
327 rtx x_last_parm_insn
;
329 /* 1 + last pseudo register number possibly used for loading a copy
330 of a parameter of this function. */
331 unsigned int x_max_parm_reg
;
333 /* Vector indexed by REGNO, containing location on stack in which
334 to put the parm which is nominally in pseudo register REGNO,
335 if we discover that that parm must go in the stack. The highest
336 element in this vector is one less than MAX_PARM_REG, above. */
337 rtx
* GTY ((length ("%h.x_max_parm_reg"))) x_parm_reg_stack_loc
;
339 /* List of all temporaries allocated, both available and in use. */
340 struct temp_slot
*x_temp_slots
;
342 /* Current nesting level for temporaries. */
343 int x_temp_slot_level
;
345 /* Current nesting level for variables in a block. */
346 int x_var_temp_slot_level
;
348 /* When temporaries are created by TARGET_EXPRs, they are created at
349 this level of temp_slot_level, so that they can remain allocated
350 until no longer needed. CLEANUP_POINT_EXPRs define the lifetime
352 int x_target_temp_slot_level
;
354 /* This slot is initialized as 0 and is added to
355 during the nested function. */
356 struct var_refs_queue
*fixup_var_refs_queue
;
358 /* For integrate.c. */
360 int no_debugging_symbols
;
361 rtvec original_arg_vector
;
362 tree original_decl_initial
;
363 /* Last insn of those whose job was to put parms into their nominal
365 rtx inl_last_parm_insn
;
366 /* Highest label number in current function. */
367 int inl_max_label_num
;
369 /* Function sequence number for profiling, debugging, etc. */
374 /* tm.h can use this to store whatever it likes. */
375 struct machine_function
* GTY ((maybe_undef (""))) machine
;
376 /* The largest alignment of slot allocated on the stack. */
377 int stack_alignment_needed
;
378 /* Preferred alignment of the end of stack frame. */
379 int preferred_stack_boundary
;
380 /* Set when the call to function itself has been emit. */
381 bool recursive_call_emit
;
383 /* Language-specific code can use this to store whatever it likes. */
384 struct language_function
* language
;
388 /* If some insns can be deferred to the delay slots of the epilogue, the
389 delay list for them is recorded here. */
390 rtx epilogue_delay_list
;
392 /* Collected bit flags. */
394 /* Nonzero if function being compiled needs to be given an address
395 where the value should be stored. */
396 unsigned int returns_struct
: 1;
398 /* Nonzero if function being compiled needs to
399 return the address of where it has put a structure value. */
400 unsigned int returns_pcc_struct
: 1;
402 /* Nonzero if the current function returns a pointer type. */
403 unsigned int returns_pointer
: 1;
405 /* Nonzero if function being compiled needs to be passed a static chain. */
406 unsigned int needs_context
: 1;
408 /* Nonzero if function being compiled can call setjmp. */
409 unsigned int calls_setjmp
: 1;
411 /* Nonzero if function being compiled can call longjmp. */
412 unsigned int calls_longjmp
: 1;
414 /* Nonzero if function being compiled can call alloca,
415 either as a subroutine or builtin. */
416 unsigned int calls_alloca
: 1;
418 /* Nonzero if the function calls __builtin_eh_return. */
419 unsigned int calls_eh_return
: 1;
421 /* Nonzero if the function calls __builtin_constant_p. */
422 unsigned int calls_constant_p
: 1;
424 /* Nonzero if function being compiled receives nonlocal gotos
425 from nested functions. */
426 unsigned int has_nonlocal_label
: 1;
428 /* Nonzero if function being compiled has nonlocal gotos to parent
430 unsigned int has_nonlocal_goto
: 1;
432 /* Nonzero if function being compiled contains nested functions. */
433 unsigned int contains_functions
: 1;
435 /* Nonzero if the function being compiled issues a computed jump. */
436 unsigned int has_computed_jump
: 1;
438 /* Nonzero if the current function is a thunk (a lightweight function that
439 just adjusts one of its arguments and forwards to another function), so
440 we should try to cut corners where we can. */
441 unsigned int is_thunk
: 1;
443 /* This bit is used by the exception handling logic. It is set if all
444 calls (if any) are sibling calls. Such functions do not have to
445 have EH tables generated, as they cannot throw. A call to such a
446 function, however, should be treated as throwing if any of its callees
448 unsigned int all_throwers_are_sibcalls
: 1;
450 /* Nonzero if instrumentation calls for function entry and exit should be
452 unsigned int instrument_entry_exit
: 1;
454 /* Nonzero if profiling code should be generated. */
455 unsigned int profile
: 1;
457 /* Nonzero if stack limit checking should be enabled in the current
459 unsigned int limit_stack
: 1;
461 /* Nonzero if current function uses stdarg.h or equivalent. */
462 unsigned int stdarg
: 1;
464 /* Nonzero if this function is being processed in function-at-a-time
465 mode. In other words, if all tree structure for this function,
466 including the BLOCK tree, is created before RTL generation
468 unsigned int x_whole_function_mode_p
: 1;
470 /* Nonzero if the back-end should not keep track of expressions that
471 determine the size of variable-sized objects. Normally, such
472 expressions are saved away, and then expanded when the next
473 function is started. For example, if a parameter has a
474 variable-sized type, then the size of the parameter is computed
475 when the function body is entered. However, some front-ends do
476 not desire this behavior. */
477 unsigned int x_dont_save_pending_sizes_p
: 1;
479 /* Nonzero if the current function uses the constant pool. */
480 unsigned int uses_const_pool
: 1;
482 /* Nonzero if the current function uses pic_offset_table_rtx. */
483 unsigned int uses_pic_offset_table
: 1;
485 /* Nonzero if the current function needs an lsda for exception handling. */
486 unsigned int uses_eh_lsda
: 1;
488 /* Nonzero if code to initialize arg_pointer_save_area has been emitted. */
489 unsigned int arg_pointer_save_area_init
: 1;
491 /* How commonly executed the function is. Initialized during branch
492 probabilities pass. */
493 enum function_frequency
{
494 /* This function most likely won't be executed at all.
495 (set only when profile feedback is available). */
496 FUNCTION_FREQUENCY_UNLIKELY_EXECUTED
,
497 /* The default value. */
498 FUNCTION_FREQUENCY_NORMAL
,
499 /* Optimize this function hard
500 (set only when profile feedback is available). */
501 FUNCTION_FREQUENCY_HOT
502 } function_frequency
;
504 /* Maximal number of entities in the single jumptable. Used to estimate
505 final flowgraph size. */
506 int max_jumptable_ents
;
509 /* The function currently being compiled. */
510 extern GTY(()) struct function
*cfun
;
512 /* Nonzero if we've already converted virtual regs to hard regs. */
513 extern int virtuals_instantiated
;
515 /* Nonzero if at least one trampoline has been created. */
516 extern int trampolines_created
;
518 /* For backward compatibility... eventually these should all go away. */
519 #define current_function_name (cfun->name)
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_needs_context (cfun->needs_context)
525 #define current_function_calls_setjmp (cfun->calls_setjmp)
526 #define current_function_calls_alloca (cfun->calls_alloca)
527 #define current_function_calls_longjmp (cfun->calls_longjmp)
528 #define current_function_calls_eh_return (cfun->calls_eh_return)
529 #define current_function_calls_constant_p (cfun->calls_constant_p)
530 #define current_function_has_computed_jump (cfun->has_computed_jump)
531 #define current_function_contains_functions (cfun->contains_functions)
532 #define current_function_is_thunk (cfun->is_thunk)
533 #define current_function_args_info (cfun->args_info)
534 #define current_function_args_size (cfun->args_size)
535 #define current_function_pretend_args_size (cfun->pretend_args_size)
536 #define current_function_outgoing_args_size (cfun->outgoing_args_size)
537 #define current_function_arg_offset_rtx (cfun->arg_offset_rtx)
538 #define current_function_stdarg (cfun->stdarg)
539 #define current_function_internal_arg_pointer (cfun->internal_arg_pointer)
540 #define current_function_return_rtx (cfun->return_rtx)
541 #define current_function_instrument_entry_exit (cfun->instrument_entry_exit)
542 #define current_function_profile (cfun->profile)
543 #define current_function_funcdef_no (cfun->funcdef_no)
544 #define current_function_limit_stack (cfun->limit_stack)
545 #define current_function_uses_pic_offset_table (cfun->uses_pic_offset_table)
546 #define current_function_uses_const_pool (cfun->uses_const_pool)
547 #define current_function_cannot_inline (cfun->cannot_inline)
548 #define current_function_epilogue_delay_list (cfun->epilogue_delay_list)
549 #define current_function_has_nonlocal_label (cfun->has_nonlocal_label)
550 #define current_function_has_nonlocal_goto (cfun->has_nonlocal_goto)
552 #define max_parm_reg (cfun->x_max_parm_reg)
553 #define parm_reg_stack_loc (cfun->x_parm_reg_stack_loc)
554 #define cleanup_label (cfun->x_cleanup_label)
555 #define return_label (cfun->x_return_label)
556 #define save_expr_regs (cfun->x_save_expr_regs)
557 #define stack_slot_list (cfun->x_stack_slot_list)
558 #define parm_birth_insn (cfun->x_parm_birth_insn)
559 #define frame_offset (cfun->x_frame_offset)
560 #define tail_recursion_label (cfun->x_tail_recursion_label)
561 #define tail_recursion_reentry (cfun->x_tail_recursion_reentry)
562 #define arg_pointer_save_area (cfun->x_arg_pointer_save_area)
563 #define rtl_expr_chain (cfun->x_rtl_expr_chain)
564 #define last_parm_insn (cfun->x_last_parm_insn)
565 #define context_display (cfun->x_context_display)
566 #define trampoline_list (cfun->x_trampoline_list)
567 #define function_call_count (cfun->x_function_call_count)
568 #define temp_slots (cfun->x_temp_slots)
569 #define temp_slot_level (cfun->x_temp_slot_level)
570 #define target_temp_slot_level (cfun->x_target_temp_slot_level)
571 #define var_temp_slot_level (cfun->x_var_temp_slot_level)
572 #define nonlocal_labels (cfun->x_nonlocal_labels)
573 #define nonlocal_goto_handler_slots (cfun->x_nonlocal_goto_handler_slots)
574 #define nonlocal_goto_handler_labels (cfun->x_nonlocal_goto_handler_labels)
575 #define nonlocal_goto_stack_level (cfun->x_nonlocal_goto_stack_level)
577 /* The FUNCTION_DECL for an inline function currently being expanded. */
578 extern tree inline_function_decl
;
580 /* Given a function decl for a containing function,
581 return the `struct function' for it. */
582 struct function
*find_function_data
PARAMS ((tree
));
584 /* Set NOTE_BLOCK for each block note in the current function. */
585 extern void identify_blocks
PARAMS ((void));
587 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
588 and create duplicate blocks. */
589 extern void reorder_blocks
PARAMS ((void));
591 /* Set BLOCK_NUMBER for all the blocks in FN. */
592 extern void number_blocks
PARAMS ((tree
));
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
PARAMS ((void));
598 /* Likewise, but for a different than the current function. */
599 extern HOST_WIDE_INT get_func_frame_size
PARAMS ((struct function
*));
601 /* A pointer to a function to create target specific, per-function
603 extern struct machine_function
* (*init_machine_status
) PARAMS ((void));
605 /* Save and restore status information for a nested function. */
606 extern void restore_emit_status
PARAMS ((struct function
*));
607 extern void free_after_parsing
PARAMS ((struct function
*));
608 extern void free_after_compilation
PARAMS ((struct function
*));
610 extern void init_varasm_status
PARAMS ((struct function
*));
613 extern void diddle_return_value
PARAMS ((void (*)(rtx
, void*), void*));
614 extern void clobber_return_register
PARAMS ((void));
615 extern void use_return_register
PARAMS ((void));
618 extern rtx get_arg_pointer_save_area
PARAMS ((struct function
*));
620 extern void init_virtual_regs
PARAMS ((struct emit_status
*));
622 /* Called once, at initialization, to initialize function.c. */
623 extern void init_function_once
PARAMS ((void));