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 /* Line number and source file of the last line-number NOTE emitted.
87 This is used to avoid generating duplicates. */
89 const char *x_last_filename
;
91 /* The length of the regno_pointer_align, regno_decl, and x_regno_reg_rtx
92 vectors. Since these vectors are needed during the expansion phase when
93 the total number of registers in the function is not yet known, the
94 vectors are copied and made bigger when necessary. */
95 int regno_pointer_align_length
;
97 /* Indexed by pseudo register number, if nonzero gives the known alignment
98 for that pseudo (if REG_POINTER is set in x_regno_reg_rtx).
99 Allocated in parallel with x_regno_reg_rtx. */
100 unsigned char * GTY ((length ("%h.regno_pointer_align_length")))
103 /* Indexed by pseudo register number, gives the rtx for that pseudo.
104 Allocated in parallel with regno_pointer_align.
106 Note MEM expressions can appear in this array due to the actions
107 of put_var_into_stack. */
108 rtx
* GTY ((length ("%h.regno_pointer_align_length"))) x_regno_reg_rtx
;
111 /* For backward compatibility... eventually these should all go away. */
112 #define reg_rtx_no (cfun->emit->x_reg_rtx_no)
113 #define seq_rtl_expr (cfun->emit->sequence_rtl_expr)
114 #define regno_reg_rtx (cfun->emit->x_regno_reg_rtx)
115 #define seq_stack (cfun->emit->sequence_stack)
117 #define REGNO_POINTER_ALIGN(REGNO) (cfun->emit->regno_pointer_align[REGNO])
119 struct expr_status
GTY(())
121 /* Number of units that we should eventually pop off the stack.
122 These are the arguments to function calls that have already returned. */
123 int x_pending_stack_adjust
;
125 /* Under some ABIs, it is the caller's responsibility to pop arguments
126 pushed for function calls. A naive implementation would simply pop
127 the arguments immediately after each call. However, if several
128 function calls are made in a row, it is typically cheaper to pop
129 all the arguments after all of the calls are complete since a
130 single pop instruction can be used. Therefore, GCC attempts to
131 defer popping the arguments until absolutely necessary. (For
132 example, at the end of a conditional, the arguments must be popped,
133 since code outside the conditional won't know whether or not the
134 arguments need to be popped.)
136 When INHIBIT_DEFER_POP is nonzero, however, the compiler does not
137 attempt to defer pops. Instead, the stack is popped immediately
138 after each call. Rather then setting this variable directly, use
139 NO_DEFER_POP and OK_DEFER_POP. */
140 int x_inhibit_defer_pop
;
142 /* If PREFERRED_STACK_BOUNDARY and PUSH_ROUNDING are defined, the stack
143 boundary can be momentarily unaligned while pushing the arguments.
144 Record the delta since last aligned boundary here in order to get
145 stack alignment in the nested function calls working right. */
146 int x_stack_pointer_delta
;
148 /* Nonzero means __builtin_saveregs has already been done in this function.
149 The value is the pseudoreg containing the value __builtin_saveregs
151 rtx x_saveregs_value
;
153 /* Similarly for __builtin_apply_args. */
154 rtx x_apply_args_value
;
156 /* List of labels that must never be deleted. */
159 /* Postincrements that still need to be expanded. */
163 #define pending_stack_adjust (cfun->expr->x_pending_stack_adjust)
164 #define inhibit_defer_pop (cfun->expr->x_inhibit_defer_pop)
165 #define saveregs_value (cfun->expr->x_saveregs_value)
166 #define apply_args_value (cfun->expr->x_apply_args_value)
167 #define forced_labels (cfun->expr->x_forced_labels)
168 #define pending_chain (cfun->expr->x_pending_chain)
169 #define stack_pointer_delta (cfun->expr->x_stack_pointer_delta)
171 /* This structure can save all the important global and static variables
172 describing the status of the current function. */
174 struct function
GTY(())
176 struct eh_status
*eh
;
177 struct stmt_status
*stmt
;
178 struct expr_status
*expr
;
179 struct emit_status
*emit
;
180 struct varasm_status
*varasm
;
182 /* For function.c. */
184 /* Name of this function. */
187 /* Points to the FUNCTION_DECL of this function. */
190 /* Function containing this function, if any. */
191 struct function
*outer
;
193 /* Number of bytes of args popped by function being compiled on its return.
194 Zero if no bytes are to be popped.
195 May affect compilation of return insn or of function epilogue. */
198 /* If function's args have a fixed size, this is that size, in bytes.
200 May affect compilation of return insn or of function epilogue. */
203 /* # bytes the prologue should push and pretend that the caller pushed them.
204 The prologue must do this, but only if parms can be passed in
206 int pretend_args_size
;
208 /* # of bytes of outgoing arguments. If ACCUMULATE_OUTGOING_ARGS is
209 defined, the needed space is pushed by the prologue. */
210 int outgoing_args_size
;
212 /* This is the offset from the arg pointer to the place where the first
213 anonymous arg can be found, if there is one. */
216 /* Quantities of various kinds of registers
217 used for the current function's args. */
218 CUMULATIVE_ARGS args_info
;
220 /* If nonzero, an RTL expression for the location at which the current
221 function returns its result. If the current function returns its
222 result in a register, current_function_return_rtx will always be
223 the hard register containing the result. */
226 /* The arg pointer hard register, or the pseudo into which it was copied. */
227 rtx internal_arg_pointer
;
229 /* Language-specific reason why the current function cannot be made
231 const char *cannot_inline
;
233 /* Opaque pointer used by get_hard_reg_initial_val and
234 has_hard_reg_initial_val (see integrate.[hc]). */
235 struct initial_value_struct
*hard_reg_initial_vals
;
237 /* Number of function calls seen so far in current function. */
238 int x_function_call_count
;
240 /* List (chain of TREE_LIST) of LABEL_DECLs for all nonlocal labels
241 (labels to which there can be nonlocal gotos from nested functions)
243 tree x_nonlocal_labels
;
245 /* List (chain of EXPR_LIST) of stack slots that hold the current handlers
246 for nonlocal gotos. There is one for every nonlocal label in the
247 function; this list matches the one in nonlocal_labels.
248 Zero when function does not have nonlocal labels. */
249 rtx x_nonlocal_goto_handler_slots
;
251 /* List (chain of EXPR_LIST) of labels heading the current handlers for
253 rtx x_nonlocal_goto_handler_labels
;
255 /* RTX for stack slot that holds the stack pointer value to restore
257 Zero when function does not have nonlocal labels. */
258 rtx x_nonlocal_goto_stack_level
;
260 /* Label that will go on parm cleanup code, if any.
261 Jumping to this label runs cleanup code for parameters, if
262 such code must be run. Following this code is the logical return
266 /* Label that will go on function epilogue.
267 Jumping to this label serves as a "return" instruction
268 on machines which require execution of the epilogue on all returns. */
271 /* List (chain of EXPR_LISTs) of pseudo-regs of SAVE_EXPRs.
272 So we can mark them all live at the end of the function, if nonopt. */
273 rtx x_save_expr_regs
;
275 /* List (chain of EXPR_LISTs) of all stack slots in this function.
276 Made for the sake of unshare_all_rtl. */
277 rtx x_stack_slot_list
;
279 /* Chain of all RTL_EXPRs that have insns in them. */
280 tree x_rtl_expr_chain
;
282 /* Label to jump back to for tail recursion, or 0 if we have
283 not yet needed one for this function. */
284 rtx x_tail_recursion_label
;
286 /* Place after which to insert the tail_recursion_label if we need one. */
287 rtx x_tail_recursion_reentry
;
289 /* Location at which to save the argument pointer if it will need to be
290 referenced. There are two cases where this is done: if nonlocal gotos
291 exist, or if vars stored at an offset from the argument pointer will be
292 needed by inner routines. */
293 rtx x_arg_pointer_save_area
;
295 /* If the function returns non-void, we will emit a clobber of the
296 return registers just in case the user fell off the end without
297 returning a proper value. This is that insn. */
298 rtx x_clobber_return_insn
;
300 /* Offset to end of allocated area of stack frame.
301 If stack grows down, this is the address of the last stack slot allocated.
302 If stack grows up, this is the address for the next slot. */
303 HOST_WIDE_INT x_frame_offset
;
305 /* List (chain of TREE_LISTs) of static chains for containing functions.
306 Each link has a FUNCTION_DECL in the TREE_PURPOSE and a reg rtx
307 in an RTL_EXPR in the TREE_VALUE. */
308 tree x_context_display
;
310 /* List (chain of TREE_LISTs) of trampolines for nested functions.
311 The trampoline sets up the static chain and jumps to the function.
312 We supply the trampoline's address when the function's address is
315 Each link has a FUNCTION_DECL in the TREE_PURPOSE and a reg rtx
316 in an RTL_EXPR in the TREE_VALUE. */
317 tree x_trampoline_list
;
319 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */
320 rtx x_parm_birth_insn
;
322 /* Last insn of those whose job was to put parms into their nominal
324 rtx x_last_parm_insn
;
326 /* 1 + last pseudo register number possibly used for loading a copy
327 of a parameter of this function. */
328 unsigned int x_max_parm_reg
;
330 /* Vector indexed by REGNO, containing location on stack in which
331 to put the parm which is nominally in pseudo register REGNO,
332 if we discover that that parm must go in the stack. The highest
333 element in this vector is one less than MAX_PARM_REG, above. */
334 rtx
* GTY ((length ("%h.x_max_parm_reg"))) x_parm_reg_stack_loc
;
336 /* List of all temporaries allocated, both available and in use. */
337 struct temp_slot
*x_temp_slots
;
339 /* Current nesting level for temporaries. */
340 int x_temp_slot_level
;
342 /* Current nesting level for variables in a block. */
343 int x_var_temp_slot_level
;
345 /* When temporaries are created by TARGET_EXPRs, they are created at
346 this level of temp_slot_level, so that they can remain allocated
347 until no longer needed. CLEANUP_POINT_EXPRs define the lifetime
349 int x_target_temp_slot_level
;
351 /* This slot is initialized as 0 and is added to
352 during the nested function. */
353 struct var_refs_queue
*fixup_var_refs_queue
;
355 /* For integrate.c. */
357 int no_debugging_symbols
;
358 rtvec original_arg_vector
;
359 tree original_decl_initial
;
360 /* Last insn of those whose job was to put parms into their nominal
362 rtx inl_last_parm_insn
;
363 /* Highest label number in current function. */
364 int inl_max_label_num
;
366 /* Function sequence number for profiling, debugging, etc. */
371 /* tm.h can use this to store whatever it likes. */
372 struct machine_function
* GTY ((maybe_undef (""))) machine
;
373 /* The largest alignment of slot allocated on the stack. */
374 int stack_alignment_needed
;
375 /* Preferred alignment of the end of stack frame. */
376 int preferred_stack_boundary
;
378 /* Language-specific code can use this to store whatever it likes. */
379 struct language_function
* language
;
383 /* If some insns can be deferred to the delay slots of the epilogue, the
384 delay list for them is recorded here. */
385 rtx epilogue_delay_list
;
387 /* Collected bit flags. */
389 /* Nonzero if function being compiled needs to be given an address
390 where the value should be stored. */
391 unsigned int returns_struct
: 1;
393 /* Nonzero if function being compiled needs to
394 return the address of where it has put a structure value. */
395 unsigned int returns_pcc_struct
: 1;
397 /* Nonzero if the current function returns a pointer type. */
398 unsigned int returns_pointer
: 1;
400 /* Nonzero if function being compiled needs to be passed a static chain. */
401 unsigned int needs_context
: 1;
403 /* Nonzero if function being compiled can call setjmp. */
404 unsigned int calls_setjmp
: 1;
406 /* Nonzero if function being compiled can call longjmp. */
407 unsigned int calls_longjmp
: 1;
409 /* Nonzero if function being compiled can call alloca,
410 either as a subroutine or builtin. */
411 unsigned int calls_alloca
: 1;
413 /* Nonzero if the function calls __builtin_eh_return. */
414 unsigned int calls_eh_return
: 1;
416 /* Nonzero if function being compiled receives nonlocal gotos
417 from nested functions. */
418 unsigned int has_nonlocal_label
: 1;
420 /* Nonzero if function being compiled has nonlocal gotos to parent
422 unsigned int has_nonlocal_goto
: 1;
424 /* Nonzero if function being compiled contains nested functions. */
425 unsigned int contains_functions
: 1;
427 /* Nonzero if the function being compiled issues a computed jump. */
428 unsigned int has_computed_jump
: 1;
430 /* Nonzero if the current function is a thunk (a lightweight function that
431 just adjusts one of its arguments and forwards to another function), so
432 we should try to cut corners where we can. */
433 unsigned int is_thunk
: 1;
435 /* This bit is used by the exception handling logic. It is set if all
436 calls (if any) are sibling calls. Such functions do not have to
437 have EH tables generated, as they cannot throw. A call to such a
438 function, however, should be treated as throwing if any of its callees
440 unsigned int all_throwers_are_sibcalls
: 1;
442 /* Nonzero if instrumentation calls for function entry and exit should be
444 unsigned int instrument_entry_exit
: 1;
446 /* Nonzero if arc profiling should be done for the function. */
447 unsigned int arc_profile
: 1;
449 /* Nonzero if profiling code should be generated. */
450 unsigned int profile
: 1;
452 /* Nonzero if stack limit checking should be enabled in the current
454 unsigned int limit_stack
: 1;
456 /* Nonzero if current function uses stdarg.h or equivalent. */
457 unsigned int stdarg
: 1;
459 /* Nonzero if this function is being processed in function-at-a-time
460 mode. In other words, if all tree structure for this function,
461 including the BLOCK tree, is created before RTL generation
463 unsigned int x_whole_function_mode_p
: 1;
465 /* Nonzero if the back-end should not keep track of expressions that
466 determine the size of variable-sized objects. Normally, such
467 expressions are saved away, and then expanded when the next
468 function is started. For example, if a parameter has a
469 variable-sized type, then the size of the parameter is computed
470 when the function body is entered. However, some front-ends do
471 not desire this behavior. */
472 unsigned int x_dont_save_pending_sizes_p
: 1;
474 /* Nonzero if the current function uses the constant pool. */
475 unsigned int uses_const_pool
: 1;
477 /* Nonzero if the current function uses pic_offset_table_rtx. */
478 unsigned int uses_pic_offset_table
: 1;
480 /* Nonzero if the current function needs an lsda for exception handling. */
481 unsigned int uses_eh_lsda
: 1;
483 /* Nonzero if code to initialize arg_pointer_save_area has been emited. */
484 unsigned int arg_pointer_save_area_init
: 1;
486 /* How commonly executed the function is. Initialized during branch
487 probabilities pass. */
488 enum function_frequency
{
489 /* This function most likely won't be executed at all.
490 (set only when profile feedback is available). */
491 FUNCTION_FREQUENCY_UNLIKELY_EXECUTED
,
492 /* The default value. */
493 FUNCTION_FREQUENCY_NORMAL
,
494 /* Optimize this function hard
495 (set only when profile feedback is available). */
496 FUNCTION_FREQUENCY_HOT
497 } function_frequency
;
499 /* Maximal number of entities in the single jumptable. Used to estimate
500 final flowgraph size. */
501 int max_jumptable_ents
;
504 /* The function currently being compiled. */
505 extern GTY(()) struct function
*cfun
;
507 /* Nonzero if we've already converted virtual regs to hard regs. */
508 extern int virtuals_instantiated
;
510 /* For backward compatibility... eventually these should all go away. */
511 #define current_function_name (cfun->name)
512 #define current_function_pops_args (cfun->pops_args)
513 #define current_function_returns_struct (cfun->returns_struct)
514 #define current_function_returns_pcc_struct (cfun->returns_pcc_struct)
515 #define current_function_returns_pointer (cfun->returns_pointer)
516 #define current_function_needs_context (cfun->needs_context)
517 #define current_function_calls_setjmp (cfun->calls_setjmp)
518 #define current_function_calls_alloca (cfun->calls_alloca)
519 #define current_function_calls_longjmp (cfun->calls_longjmp)
520 #define current_function_calls_eh_return (cfun->calls_eh_return)
521 #define current_function_has_computed_jump (cfun->has_computed_jump)
522 #define current_function_contains_functions (cfun->contains_functions)
523 #define current_function_is_thunk (cfun->is_thunk)
524 #define current_function_args_info (cfun->args_info)
525 #define current_function_args_size (cfun->args_size)
526 #define current_function_pretend_args_size (cfun->pretend_args_size)
527 #define current_function_outgoing_args_size (cfun->outgoing_args_size)
528 #define current_function_arg_offset_rtx (cfun->arg_offset_rtx)
529 #define current_function_stdarg (cfun->stdarg)
530 #define current_function_internal_arg_pointer (cfun->internal_arg_pointer)
531 #define current_function_return_rtx (cfun->return_rtx)
532 #define current_function_instrument_entry_exit (cfun->instrument_entry_exit)
533 #define current_function_profile (cfun->profile)
534 #define current_function_funcdef_no (cfun->funcdef_no)
535 #define current_function_limit_stack (cfun->limit_stack)
536 #define current_function_uses_pic_offset_table (cfun->uses_pic_offset_table)
537 #define current_function_uses_const_pool (cfun->uses_const_pool)
538 #define current_function_cannot_inline (cfun->cannot_inline)
539 #define current_function_epilogue_delay_list (cfun->epilogue_delay_list)
540 #define current_function_has_nonlocal_label (cfun->has_nonlocal_label)
541 #define current_function_has_nonlocal_goto (cfun->has_nonlocal_goto)
543 #define max_parm_reg (cfun->x_max_parm_reg)
544 #define parm_reg_stack_loc (cfun->x_parm_reg_stack_loc)
545 #define cleanup_label (cfun->x_cleanup_label)
546 #define return_label (cfun->x_return_label)
547 #define save_expr_regs (cfun->x_save_expr_regs)
548 #define stack_slot_list (cfun->x_stack_slot_list)
549 #define parm_birth_insn (cfun->x_parm_birth_insn)
550 #define frame_offset (cfun->x_frame_offset)
551 #define tail_recursion_label (cfun->x_tail_recursion_label)
552 #define tail_recursion_reentry (cfun->x_tail_recursion_reentry)
553 #define arg_pointer_save_area (cfun->x_arg_pointer_save_area)
554 #define rtl_expr_chain (cfun->x_rtl_expr_chain)
555 #define last_parm_insn (cfun->x_last_parm_insn)
556 #define context_display (cfun->x_context_display)
557 #define trampoline_list (cfun->x_trampoline_list)
558 #define function_call_count (cfun->x_function_call_count)
559 #define temp_slots (cfun->x_temp_slots)
560 #define temp_slot_level (cfun->x_temp_slot_level)
561 #define target_temp_slot_level (cfun->x_target_temp_slot_level)
562 #define var_temp_slot_level (cfun->x_var_temp_slot_level)
563 #define nonlocal_labels (cfun->x_nonlocal_labels)
564 #define nonlocal_goto_handler_slots (cfun->x_nonlocal_goto_handler_slots)
565 #define nonlocal_goto_handler_labels (cfun->x_nonlocal_goto_handler_labels)
566 #define nonlocal_goto_stack_level (cfun->x_nonlocal_goto_stack_level)
568 /* The FUNCTION_DECL for an inline function currently being expanded. */
569 extern tree inline_function_decl
;
571 /* Given a function decl for a containing function,
572 return the `struct function' for it. */
573 struct function
*find_function_data
PARAMS ((tree
));
575 /* Set NOTE_BLOCK for each block note in the current function. */
576 extern void identify_blocks
PARAMS ((void));
578 /* Identify BLOCKs referenced by more than one NOTE_INSN_BLOCK_{BEG,END},
579 and create duplicate blocks. */
580 extern void reorder_blocks
PARAMS ((void));
582 /* Set BLOCK_NUMBER for all the blocks in FN. */
583 extern void number_blocks
PARAMS ((tree
));
585 /* Return size needed for stack frame based on slots so far allocated.
586 This size counts from zero. It is not rounded to STACK_BOUNDARY;
587 the caller may have to do that. */
588 extern HOST_WIDE_INT get_frame_size
PARAMS ((void));
589 /* Likewise, but for a different than the current function. */
590 extern HOST_WIDE_INT get_func_frame_size
PARAMS ((struct function
*));
592 /* A pointer to a function to create target specific, per-function
594 extern struct machine_function
* (*init_machine_status
) PARAMS ((void));
596 /* Save and restore status information for a nested function. */
597 extern void restore_emit_status
PARAMS ((struct function
*));
598 extern void free_after_parsing
PARAMS ((struct function
*));
599 extern void free_after_compilation
PARAMS ((struct function
*));
601 extern void init_varasm_status
PARAMS ((struct function
*));
604 extern void diddle_return_value
PARAMS ((void (*)(rtx
, void*), void*));
605 extern void clobber_return_register
PARAMS ((void));
606 extern void use_return_register
PARAMS ((void));
609 extern rtx get_arg_pointer_save_area
PARAMS ((struct function
*));
611 extern void init_virtual_regs
PARAMS ((struct emit_status
*));
613 /* Called once, at initialization, to initialize function.c. */
614 extern void init_function_once
PARAMS ((void));