1 /* Expands front end tree to back end RTL for GNU C-Compiler
2 Copyright (C) 1987, 1988, 1989, 1991 Free Software Foundation, Inc.
4 This file is part of GNU CC.
6 GNU CC is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 GNU CC is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GNU CC; see the file COPYING. If not, write to
18 the Free Software Foundation, 675 Mass Ave, Cambridge, MA 02139, USA. */
21 /* This file handles the generation of rtl code from tree structure
22 at the level of the function as a whole.
23 It creates the rtl expressions for parameters and auto variables
24 and has full responsibility for allocating stack slots.
26 `expand_function_start' is called at the beginning of a function,
27 before the function body is parsed, and `expand_function_end' is
28 called after parsing the body.
30 Call `assign_stack_local' to allocate a stack slot for a local variable.
31 This is usually done during the RTL generation for the function body,
32 but it can also be done in the reload pass when a pseudo-register does
33 not get a hard register.
35 Call `put_var_into_stack' when you learn, belatedly, that a variable
36 previously given a pseudo-register must in fact go in the stack.
37 This function changes the DECL_RTL to be a stack slot instead of a reg
38 then scans all the RTL instructions so far generated to correct them. */
48 #include "insn-flags.h"
50 #include "insn-codes.h"
52 #include "hard-reg-set.h"
53 #include "insn-config.h"
56 #include "basic-block.h"
58 /* Round a value to the lowest integer less than it that is a multiple of
59 the required alignment. Avoid using division in case the value is
60 negative. Assume the alignment is a power of two. */
61 #define FLOOR_ROUND(VALUE,ALIGN) ((VALUE) & ~((ALIGN) - 1))
63 /* Similar, but round to the next highest integer that meets the
65 #define CEIL_ROUND(VALUE,ALIGN) (((VALUE) + (ALIGN) - 1) & ~((ALIGN)- 1))
67 /* NEED_SEPARATE_AP means that we cannot derive ap from the value of fp
68 during rtl generation. If they are different register numbers, this is
69 always true. It may also be true if
70 FIRST_PARM_OFFSET - STARTING_FRAME_OFFSET is not a constant during rtl
71 generation. See fix_lexical_addr for details. */
73 #if ARG_POINTER_REGNUM != FRAME_POINTER_REGNUM
74 #define NEED_SEPARATE_AP
77 /* Number of bytes of args popped by function being compiled on its return.
78 Zero if no bytes are to be popped.
79 May affect compilation of return insn or of function epilogue. */
81 int current_function_pops_args;
83 /* Nonzero if function being compiled needs to be given an address
84 where the value should be stored. */
86 int current_function_returns_struct;
88 /* Nonzero if function being compiled needs to
89 return the address of where it has put a structure value. */
91 int current_function_returns_pcc_struct;
93 /* Nonzero if function being compiled needs to be passed a static chain. */
95 int current_function_needs_context;
97 /* Nonzero if function being compiled can call setjmp. */
99 int current_function_calls_setjmp;
101 /* Nonzero if function being compiled can call longjmp. */
103 int current_function_calls_longjmp;
105 /* Nonzero if function being compiled receives nonlocal gotos
106 from nested functions. */
108 int current_function_has_nonlocal_label;
110 /* Nonzero if function being compiled contains nested functions. */
112 int current_function_contains_functions;
114 /* Nonzero if function being compiled can call alloca,
115 either as a subroutine or builtin. */
117 int current_function_calls_alloca;
119 /* Nonzero if the current function returns a pointer type */
121 int current_function_returns_pointer;
123 /* If some insns can be deferred to the delay slots of the epilogue, the
124 delay list for them is recorded here. */
126 rtx current_function_epilogue_delay_list;
128 /* If function's args have a fixed size, this is that size, in bytes.
130 May affect compilation of return insn or of function epilogue. */
132 int current_function_args_size;
134 /* # bytes the prologue should push and pretend that the caller pushed them.
135 The prologue must do this, but only if parms can be passed in registers. */
137 int current_function_pretend_args_size;
139 /* # of bytes of outgoing arguments required to be pushed by the prologue.
140 If this is non-zero, it means that ACCUMULATE_OUTGOING_ARGS was defined
141 and no stack adjusts will be done on function calls. */
143 int current_function_outgoing_args_size;
145 /* This is the offset from the arg pointer to the place where the first
146 anonymous arg can be found, if there is one. */
148 rtx current_function_arg_offset_rtx;
150 /* Nonzero if current function uses varargs.h or equivalent.
151 Zero for functions that use stdarg.h. */
153 int current_function_varargs;
155 /* Quantities of various kinds of registers
156 used for the current function's args. */
158 CUMULATIVE_ARGS current_function_args_info;
160 /* Name of function now being compiled. */
162 char *current_function_name;
164 /* If non-zero, an RTL expression for that location at which the current
165 function returns its result. Always equal to
166 DECL_RTL (DECL_RESULT (current_function_decl)), but provided
167 independently of the tree structures. */
169 rtx current_function_return_rtx;
171 /* Nonzero if the current function uses the constant pool. */
173 int current_function_uses_const_pool;
175 /* Nonzero if the current function uses pic_offset_table_rtx. */
176 int current_function_uses_pic_offset_table;
178 /* The arg pointer hard register, or the pseudo into which it was copied. */
179 rtx current_function_internal_arg_pointer;
181 /* The FUNCTION_DECL for an inline function currently being expanded. */
182 tree inline_function_decl;
184 /* Number of function calls seen so far in current function. */
186 int function_call_count;
188 /* List (chain of TREE_LIST) of LABEL_DECLs for all nonlocal labels
189 (labels to which there can be nonlocal gotos from nested functions)
192 tree nonlocal_labels;
194 /* RTX for stack slot that holds the current handler for nonlocal gotos.
195 Zero when function does not have nonlocal labels. */
197 rtx nonlocal_goto_handler_slot;
199 /* RTX for stack slot that holds the stack pointer value to restore
201 Zero when function does not have nonlocal labels. */
203 rtx nonlocal_goto_stack_level;
205 /* Label that will go on parm cleanup code, if any.
206 Jumping to this label runs cleanup code for parameters, if
207 such code must be run. Following this code is the logical return label. */
211 /* Label that will go on function epilogue.
212 Jumping to this label serves as a "return" instruction
213 on machines which require execution of the epilogue on all returns. */
217 /* List (chain of EXPR_LISTs) of pseudo-regs of SAVE_EXPRs.
218 So we can mark them all live at the end of the function, if nonopt. */
221 /* List (chain of EXPR_LISTs) of all stack slots in this function.
222 Made for the sake of unshare_all_rtl. */
225 /* Chain of all RTL_EXPRs that have insns in them. */
228 /* Label to jump back to for tail recursion, or 0 if we have
229 not yet needed one for this function. */
230 rtx tail_recursion_label;
232 /* Place after which to insert the tail_recursion_label if we need one. */
233 rtx tail_recursion_reentry;
235 /* Location at which to save the argument pointer if it will need to be
236 referenced. There are two cases where this is done: if nonlocal gotos
237 exist, or if vars stored at an offset from the argument pointer will be
238 needed by inner routines. */
240 rtx arg_pointer_save_area;
242 /* Offset to end of allocated area of stack frame.
243 If stack grows down, this is the address of the last stack slot allocated.
244 If stack grows up, this is the address for the next slot. */
247 /* List (chain of TREE_LISTs) of static chains for containing functions.
248 Each link has a FUNCTION_DECL in the TREE_PURPOSE and a reg rtx
249 in an RTL_EXPR in the TREE_VALUE. */
250 static tree context_display;
252 /* List (chain of TREE_LISTs) of trampolines for nested functions.
253 The trampoline sets up the static chain and jumps to the function.
254 We supply the trampoline's address when the function's address is requested.
256 Each link has a FUNCTION_DECL in the TREE_PURPOSE and a reg rtx
257 in an RTL_EXPR in the TREE_VALUE. */
258 static tree trampoline_list;
260 /* Insn after which register parms and SAVE_EXPRs are born, if nonopt. */
261 static rtx parm_birth_insn;
264 /* Nonzero if a stack slot has been generated whose address is not
265 actually valid. It means that the generated rtl must all be scanned
266 to detect and correct the invalid addresses where they occur. */
267 static int invalid_stack_slot;
270 /* Last insn of those whose job was to put parms into their nominal homes. */
271 static rtx last_parm_insn;
273 /* 1 + last pseudo register number used for loading a copy
274 of a parameter of this function. */
275 static int max_parm_reg;
277 /* Vector indexed by REGNO, containing location on stack in which
278 to put the parm which is nominally in pseudo register REGNO,
279 if we discover that that parm must go in the stack. */
280 static rtx *parm_reg_stack_loc;
282 #if 0 /* Turned off because 0 seems to work just as well. */
283 /* Cleanup lists are required for binding levels regardless of whether
284 that binding level has cleanups or not. This node serves as the
285 cleanup list whenever an empty list is required. */
286 static tree empty_cleanup_list;
289 /* Nonzero once virtual register instantiation has been done.
290 assign_stack_local uses frame_pointer_rtx when this is nonzero. */
291 static int virtuals_instantiated;
293 /* Nonzero if we need to distinguish between the return value of this function
294 and the return value of a function called by this function. This helps
297 extern int rtx_equal_function_value_matters;
301 static tree round_down ();
302 static rtx round_trampoline_addr ();
303 static rtx fixup_stack_1 ();
304 static void fixup_var_refs ();
305 static void fixup_var_refs_insns ();
306 static void fixup_var_refs_1 ();
307 static void optimize_bit_field ();
308 static void instantiate_decls ();
309 static void instantiate_decls_1 ();
310 static int instantiate_virtual_regs_1 ();
311 static rtx fixup_memory_subreg ();
312 static rtx walk_fixup_memory_subreg ();
314 /* In order to evaluate some expressions, such as function calls returning
315 structures in memory, we need to temporarily allocate stack locations.
316 We record each allocated temporary in the following structure.
318 Associated with each temporary slot is a nesting level. When we pop up
319 one level, all temporaries associated with the previous level are freed.
320 Normally, all temporaries are freed after the execution of the statement
321 in which they were created. However, if we are inside a ({...}) grouping,
322 the result may be in a temporary and hence must be preserved. If the
323 result could be in a temporary, we preserve it if we can determine which
324 one it is in. If we cannot determine which temporary may contain the
325 result, all temporaries are preserved. A temporary is preserved by
326 pretending it was allocated at the previous nesting level.
328 Automatic variables are also assigned temporary slots, at the nesting
329 level where they are defined. They are marked a "kept" so that
330 free_temp_slots will not free them. */
334 /* Points to next temporary slot. */
335 struct temp_slot *next;
336 /* The rtx to used to reference the slot. */
338 /* The size, in units, of the slot. */
340 /* Non-zero if this temporary is currently in use. */
342 /* Nesting level at which this slot is being used. */
344 /* Non-zero if this should survive a call to free_temp_slots. */
348 /* List of all temporaries allocated, both available and in use. */
350 struct temp_slot *temp_slots;
352 /* Current nesting level for temporaries. */
356 /* Pointer to chain of `struct function' for containing functions. */
357 struct function *outer_function_chain;
359 /* Given a function decl for a containing function,
360 return the `struct function' for it. */
363 find_function_data (decl)
367 for (p = outer_function_chain; p; p = p->next)
373 /* Save the current context for compilation of a nested function.
374 This is called from language-specific code.
375 The caller is responsible for saving any language-specific status,
376 since this function knows only about language-independent variables. */
379 push_function_context ()
381 struct function *p = (struct function *) xmalloc (sizeof (struct function));
383 p->next = outer_function_chain;
384 outer_function_chain = p;
386 p->name = current_function_name;
387 p->decl = current_function_decl;
388 p->pops_args = current_function_pops_args;
389 p->returns_struct = current_function_returns_struct;
390 p->returns_pcc_struct = current_function_returns_pcc_struct;
391 p->needs_context = current_function_needs_context;
392 p->calls_setjmp = current_function_calls_setjmp;
393 p->calls_longjmp = current_function_calls_longjmp;
394 p->calls_alloca = current_function_calls_alloca;
395 p->has_nonlocal_label = current_function_has_nonlocal_label;
396 p->args_size = current_function_args_size;
397 p->pretend_args_size = current_function_pretend_args_size;
398 p->arg_offset_rtx = current_function_arg_offset_rtx;
399 p->uses_const_pool = current_function_uses_const_pool;
400 p->uses_pic_offset_table = current_function_uses_pic_offset_table;
401 p->internal_arg_pointer = current_function_internal_arg_pointer;
402 p->max_parm_reg = max_parm_reg;
403 p->parm_reg_stack_loc = parm_reg_stack_loc;
404 p->outgoing_args_size = current_function_outgoing_args_size;
405 p->return_rtx = current_function_return_rtx;
406 p->nonlocal_goto_handler_slot = nonlocal_goto_handler_slot;
407 p->nonlocal_goto_stack_level = nonlocal_goto_stack_level;
408 p->nonlocal_labels = nonlocal_labels;
409 p->cleanup_label = cleanup_label;
410 p->return_label = return_label;
411 p->save_expr_regs = save_expr_regs;
412 p->stack_slot_list = stack_slot_list;
413 p->parm_birth_insn = parm_birth_insn;
414 p->frame_offset = frame_offset;
415 p->tail_recursion_label = tail_recursion_label;
416 p->tail_recursion_reentry = tail_recursion_reentry;
417 p->arg_pointer_save_area = arg_pointer_save_area;
418 p->rtl_expr_chain = rtl_expr_chain;
419 p->last_parm_insn = last_parm_insn;
420 p->context_display = context_display;
421 p->trampoline_list = trampoline_list;
422 p->function_call_count = function_call_count;
423 p->temp_slots = temp_slots;
424 p->temp_slot_level = temp_slot_level;
425 p->fixup_var_refs_queue = 0;
427 save_tree_status (p);
428 save_storage_status (p);
429 save_emit_status (p);
431 save_expr_status (p);
432 save_stmt_status (p);
435 /* Restore the last saved context, at the end of a nested function.
436 This function is called from language-specific code. */
439 pop_function_context ()
441 struct function *p = outer_function_chain;
443 outer_function_chain = p->next;
445 current_function_name = p->name;
446 current_function_decl = p->decl;
447 current_function_pops_args = p->pops_args;
448 current_function_returns_struct = p->returns_struct;
449 current_function_returns_pcc_struct = p->returns_pcc_struct;
450 current_function_needs_context = p->needs_context;
451 current_function_calls_setjmp = p->calls_setjmp;
452 current_function_calls_longjmp = p->calls_longjmp;
453 current_function_calls_alloca = p->calls_alloca;
454 current_function_has_nonlocal_label = p->has_nonlocal_label;
455 current_function_contains_functions = 1;
456 current_function_args_size = p->args_size;
457 current_function_pretend_args_size = p->pretend_args_size;
458 current_function_arg_offset_rtx = p->arg_offset_rtx;
459 current_function_uses_const_pool = p->uses_const_pool;
460 current_function_uses_pic_offset_table = p->uses_pic_offset_table;
461 current_function_internal_arg_pointer = p->internal_arg_pointer;
462 max_parm_reg = p->max_parm_reg;
463 parm_reg_stack_loc = p->parm_reg_stack_loc;
464 current_function_outgoing_args_size = p->outgoing_args_size;
465 current_function_return_rtx = p->return_rtx;
466 nonlocal_goto_handler_slot = p->nonlocal_goto_handler_slot;
467 nonlocal_goto_stack_level = p->nonlocal_goto_stack_level;
468 nonlocal_labels = p->nonlocal_labels;
469 cleanup_label = p->cleanup_label;
470 return_label = p->return_label;
471 save_expr_regs = p->save_expr_regs;
472 stack_slot_list = p->stack_slot_list;
473 parm_birth_insn = p->parm_birth_insn;
474 frame_offset = p->frame_offset;
475 tail_recursion_label = p->tail_recursion_label;
476 tail_recursion_reentry = p->tail_recursion_reentry;
477 arg_pointer_save_area = p->arg_pointer_save_area;
478 rtl_expr_chain = p->rtl_expr_chain;
479 last_parm_insn = p->last_parm_insn;
480 context_display = p->context_display;
481 trampoline_list = p->trampoline_list;
482 function_call_count = p->function_call_count;
483 temp_slots = p->temp_slots;
484 temp_slot_level = p->temp_slot_level;
486 restore_tree_status (p);
487 restore_storage_status (p);
488 restore_expr_status (p);
489 restore_emit_status (p);
490 restore_stmt_status (p);
492 /* Finish doing put_var_into_stack for any of our variables
493 which became addressable during the nested function. */
495 struct var_refs_queue *queue = p->fixup_var_refs_queue;
496 for (; queue; queue = queue->next)
497 fixup_var_refs (queue->modified);
502 /* Reset variables that have known state during rtx generation. */
503 rtx_equal_function_value_matters = 1;
504 virtuals_instantiated = 0;
507 /* Allocate fixed slots in the stack frame of the current function. */
509 /* Return size needed for stack frame based on slots so far allocated.
510 This size counts from zero. It is not rounded to STACK_BOUNDARY;
511 the caller may have to do that. */
516 #ifdef FRAME_GROWS_DOWNWARD
517 return -frame_offset;
523 /* Allocate a stack slot of SIZE bytes and return a MEM rtx for it
524 with machine mode MODE.
526 ALIGN controls the amount of alignment for the address of the slot:
527 0 means according to MODE,
528 -1 means use BIGGEST_ALIGNMENT and round size to multiple of that,
529 positive specifies alignment boundary in bits.
531 We do not round to stack_boundary here. */
534 assign_stack_local (mode, size, align)
535 enum machine_mode mode;
539 register rtx x, addr;
540 int bigend_correction = 0;
545 alignment = GET_MODE_ALIGNMENT (mode) / BITS_PER_UNIT;
547 alignment = BIGGEST_ALIGNMENT / BITS_PER_UNIT;
549 else if (align == -1)
551 alignment = BIGGEST_ALIGNMENT / BITS_PER_UNIT;
552 size = CEIL_ROUND (size, alignment);
555 alignment = align / BITS_PER_UNIT;
557 /* Round frame offset to that alignment.
558 We must be careful here, since FRAME_OFFSET might be negative and
559 division with a negative dividend isn't as well defined as we might
560 like. So we instead assume that ALIGNMENT is a power of two and
561 use logical operations which are unambiguous. */
562 #ifdef FRAME_GROWS_DOWNWARD
563 frame_offset = FLOOR_ROUND (frame_offset, alignment);
565 frame_offset = CEIL_ROUND (frame_offset, alignment);
568 /* On a big-endian machine, if we are allocating more space than we will use,
569 use the least significant bytes of those that are allocated. */
572 bigend_correction = size - GET_MODE_SIZE (mode);
575 #ifdef FRAME_GROWS_DOWNWARD
576 frame_offset -= size;
579 /* If we have already instantiated virtual registers, return the actual
580 address relative to the frame pointer. */
581 if (virtuals_instantiated)
582 addr = plus_constant (frame_pointer_rtx,
583 (frame_offset + bigend_correction
584 + STARTING_FRAME_OFFSET));
586 addr = plus_constant (virtual_stack_vars_rtx,
587 frame_offset + bigend_correction);
589 #ifndef FRAME_GROWS_DOWNWARD
590 frame_offset += size;
593 x = gen_rtx (MEM, mode, addr);
595 stack_slot_list = gen_rtx (EXPR_LIST, VOIDmode, x, stack_slot_list);
600 /* Assign a stack slot in a containing function.
601 First three arguments are same as in preceding function.
602 The last argument specifies the function to allocate in. */
605 assign_outer_stack_local (mode, size, align, function)
606 enum machine_mode mode;
609 struct function *function;
611 register rtx x, addr;
612 int bigend_correction = 0;
615 /* Allocate in the memory associated with the function in whose frame
617 push_obstacks (function->function_obstack,
618 function->function_maybepermanent_obstack);
622 alignment = GET_MODE_ALIGNMENT (mode) / BITS_PER_UNIT;
624 alignment = BIGGEST_ALIGNMENT / BITS_PER_UNIT;
626 else if (align == -1)
628 alignment = BIGGEST_ALIGNMENT / BITS_PER_UNIT;
629 size = CEIL_ROUND (size, alignment);
632 alignment = align / BITS_PER_UNIT;
634 /* Round frame offset to that alignment. */
635 #ifdef FRAME_GROWS_DOWNWARD
636 frame_offset = FLOOR_ROUND (frame_offset, alignment);
638 frame_offset = CEIL_ROUND (frame_offset, alignment);
641 /* On a big-endian machine, if we are allocating more space than we will use,
642 use the least significant bytes of those that are allocated. */
645 bigend_correction = size - GET_MODE_SIZE (mode);
648 #ifdef FRAME_GROWS_DOWNWARD
649 function->frame_offset -= size;
651 addr = plus_constant (virtual_stack_vars_rtx,
652 function->frame_offset + bigend_correction);
653 #ifndef FRAME_GROWS_DOWNWARD
654 function->frame_offset += size;
657 x = gen_rtx (MEM, mode, addr);
659 function->stack_slot_list
660 = gen_rtx (EXPR_LIST, VOIDmode, x, function->stack_slot_list);
667 /* Allocate a temporary stack slot and record it for possible later
670 MODE is the machine mode to be given to the returned rtx.
672 SIZE is the size in units of the space required. We do no rounding here
673 since assign_stack_local will do any required rounding.
675 KEEP is non-zero if this slot is to be retained after a call to
676 free_temp_slots. Automatic variables for a block are allocated with this
680 assign_stack_temp (mode, size, keep)
681 enum machine_mode mode;
685 struct temp_slot *p, *best_p = 0;
687 /* First try to find an available, already-allocated temporary that is the
688 exact size we require. */
689 for (p = temp_slots; p; p = p->next)
690 if (p->size == size && GET_MODE (p->slot) == mode && ! p->in_use)
693 /* If we didn't find, one, try one that is larger than what we want. We
694 find the smallest such. */
696 for (p = temp_slots; p; p = p->next)
697 if (p->size > size && GET_MODE (p->slot) == mode && ! p->in_use
698 && (best_p == 0 || best_p->size > p->size))
701 /* Make our best, if any, the one to use. */
705 /* If we still didn't find one, make a new temporary. */
708 p = (struct temp_slot *) oballoc (sizeof (struct temp_slot));
710 /* If the temp slot mode doesn't indicate the alignment,
711 use the largest possible, so no one will be disappointed. */
712 p->slot = assign_stack_local (mode, size, mode == BLKmode ? -1 : 0);
713 p->next = temp_slots;
718 p->level = temp_slot_level;
723 /* If X could be a reference to a temporary slot, mark that slot as belonging
724 to the to one level higher. If X matched one of our slots, just mark that
725 one. Otherwise, we can't easily predict which it is, so upgrade all of
726 them. Kept slots need not be touched.
728 This is called when an ({...}) construct occurs and a statement
729 returns a value in memory. */
732 preserve_temp_slots (x)
737 /* If X is not in memory or is at a constant address, it cannot be in
739 if (x == 0 || GET_CODE (x) != MEM || CONSTANT_P (XEXP (x, 0)))
742 /* First see if we can find a match. */
743 for (p = temp_slots; p; p = p->next)
744 if (p->in_use && x == p->slot)
750 /* Otherwise, preserve all non-kept slots at this level. */
751 for (p = temp_slots; p; p = p->next)
752 if (p->in_use && p->level == temp_slot_level && ! p->keep)
756 /* Free all temporaries used so far. This is normally called at the end
757 of generating code for a statement. */
764 for (p = temp_slots; p; p = p->next)
765 if (p->in_use && p->level == temp_slot_level && ! p->keep)
769 /* Push deeper into the nesting level for stack temporaries. */
774 /* For GNU C++, we must allow a sequence to be emitted anywhere in
775 the level where the sequence was started. By not changing levels
776 when the compiler is inside a sequence, the temporaries for the
777 sequence and the temporaries will not unwittingly conflict with
778 the temporaries for other sequences and/or code at that level. */
779 if (in_sequence_p ())
785 /* Pop a temporary nesting level. All slots in use in the current level
793 /* See comment in push_temp_slots about why we don't change levels
795 if (in_sequence_p ())
798 for (p = temp_slots; p; p = p->next)
799 if (p->in_use && p->level == temp_slot_level)
805 /* Retroactively move an auto variable from a register to a stack slot.
806 This is done when an address-reference to the variable is seen. */
809 put_var_into_stack (decl)
813 register rtx new = 0;
814 struct function *function = 0;
815 tree context = decl_function_context (decl);
817 /* Get the current rtl used for this object. */
818 reg = TREE_CODE (decl) == SAVE_EXPR ? SAVE_EXPR_RTL (decl) : DECL_RTL (decl);
820 /* If this variable comes from an outer function,
821 find that function's saved context. */
822 if (context != current_function_decl)
823 for (function = outer_function_chain; function; function = function->next)
824 if (function->decl == context)
827 /* No need to do anything if decl has no rtx yet
828 since in that case caller is setting TREE_ADDRESSABLE
829 and a stack slot will be assigned when the rtl is made. */
833 /* If this is a variable-size object with a pseudo to address it,
834 put that pseudo into the stack, if the var is nonlocal. */
835 if (TREE_NONLOCAL (decl)
836 && GET_CODE (reg) == MEM
837 && GET_CODE (XEXP (reg, 0)) == REG
838 && REGNO (XEXP (reg, 0)) > LAST_VIRTUAL_REGISTER)
840 if (GET_CODE (reg) != REG)
845 if (REGNO (reg) < function->max_parm_reg)
846 new = function->parm_reg_stack_loc[REGNO (reg)];
848 new = assign_outer_stack_local (GET_MODE (reg),
849 GET_MODE_SIZE (GET_MODE (reg)),
854 if (REGNO (reg) < max_parm_reg)
855 new = parm_reg_stack_loc[REGNO (reg)];
857 new = assign_stack_local (GET_MODE (reg),
858 GET_MODE_SIZE (GET_MODE (reg)),
862 XEXP (reg, 0) = XEXP (new, 0);
863 /* `volatil' bit means one thing for MEMs, another entirely for REGs. */
864 REG_USERVAR_P (reg) = 0;
867 /* If this is a memory ref that contains aggregate components,
868 mark it as such for cse and loop optimize. */
869 MEM_IN_STRUCT_P (reg)
870 = (TREE_CODE (TREE_TYPE (decl)) == ARRAY_TYPE
871 || TREE_CODE (TREE_TYPE (decl)) == RECORD_TYPE
872 || TREE_CODE (TREE_TYPE (decl)) == UNION_TYPE);
874 /* Now make sure that all refs to the variable, previously made
875 when it was a register, are fixed up to be valid again. */
878 struct var_refs_queue *temp;
880 /* Variable is inherited; fix it up when we get back to its function. */
881 push_obstacks (function->function_obstack,
882 function->function_maybepermanent_obstack);
884 = (struct var_refs_queue *) oballoc (sizeof (struct var_refs_queue));
885 temp->modified = reg;
886 temp->next = function->fixup_var_refs_queue;
887 function->fixup_var_refs_queue = temp;
891 /* Variable is local; fix it up now. */
892 fixup_var_refs (reg);
900 rtx first_insn = get_insns ();
901 struct sequence_stack *stack = sequence_stack;
902 tree rtl_exps = rtl_expr_chain;
904 /* Must scan all insns for stack-refs that exceed the limit. */
905 fixup_var_refs_insns (var, first_insn, stack == 0);
907 /* Scan all pending sequences too. */
908 for (; stack; stack = stack->next)
910 push_to_sequence (stack->first);
911 fixup_var_refs_insns (var, stack->first, stack->next != 0);
912 /* Update remembered end of sequence
913 in case we added an insn at the end. */
914 stack->last = get_last_insn ();
918 /* Scan all waiting RTL_EXPRs too. */
919 for (pending = rtl_exps; pending; pending = TREE_CHAIN (pending))
921 rtx seq = RTL_EXPR_SEQUENCE (TREE_VALUE (pending));
922 if (seq != const0_rtx && seq != 0)
924 push_to_sequence (seq);
925 fixup_var_refs_insns (var, seq, 0);
931 /* This structure is used by the following two functions to record MEMs or
932 pseudos used to replace VAR, any SUBREGs of VAR, and any MEMs containing
933 VAR as an address. We need to maintain this list in case two operands of
934 an insn were required to match; in that case we must ensure we use the
937 struct fixup_replacement
941 struct fixup_replacement *next;
944 /* REPLACEMENTS is a pointer to a list of the above structures and X is
945 some part of an insn. Return a struct fixup_replacement whose OLD
946 value is equal to X. Allocate a new structure if no such entry exists. */
948 static struct fixup_replacement *
949 find_replacement (replacements, x)
950 struct fixup_replacement **replacements;
953 struct fixup_replacement *p;
955 /* See if we have already replaced this. */
956 for (p = *replacements; p && p->old != x; p = p->next)
961 p = (struct fixup_replacement *) oballoc (sizeof (struct fixup_replacement));
964 p->next = *replacements;
971 /* Scan the insn-chain starting with INSN for refs to VAR
972 and fix them up. TOPLEVEL is nonzero if this chain is the
973 main chain of insns for the current function. */
976 fixup_var_refs_insns (var, insn, toplevel)
983 rtx next = NEXT_INSN (insn);
985 if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN
986 || GET_CODE (insn) == JUMP_INSN)
988 /* The insn to load VAR from a home in the arglist
989 is now a no-op. When we see it, just delete it. */
991 && GET_CODE (PATTERN (insn)) == SET
992 && SET_DEST (PATTERN (insn)) == var
993 && rtx_equal_p (SET_SRC (PATTERN (insn)), var))
995 next = delete_insn (insn);
996 if (insn == last_parm_insn)
997 last_parm_insn = PREV_INSN (next);
1001 /* See if we have to do anything to INSN now that VAR is in
1002 memory. If it needs to be loaded into a pseudo, use a single
1003 pseudo for the entire insn in case there is a MATCH_DUP
1004 between two operands. We pass a pointer to the head of
1005 a list of struct fixup_replacements. If fixup_var_refs_1
1006 needs to allocate pseudos or replacement MEMs (for SUBREGs),
1007 it will record them in this list.
1009 If it allocated a pseudo for any replacement, we copy into
1012 struct fixup_replacement *replacements = 0;
1014 fixup_var_refs_1 (var, &PATTERN (insn), insn, &replacements);
1016 while (replacements)
1018 if (GET_CODE (replacements->new) == REG)
1022 /* OLD might be a (subreg (mem)). */
1023 if (GET_CODE (replacements->old) == SUBREG)
1025 = fixup_memory_subreg (replacements->old, insn, 0);
1028 = fixup_stack_1 (replacements->old, insn);
1030 /* We can not separate USE insns from the CALL_INSN
1031 that they belong to. If this is a CALL_INSN, insert
1032 the move insn before the USE insns preceding it
1033 instead of immediately before the insn. */
1034 if (GET_CODE (insn) == CALL_INSN)
1036 insert_before = insn;
1037 while (GET_CODE (PREV_INSN (insert_before)) == INSN
1038 && GET_CODE (PATTERN (PREV_INSN (insert_before))) == USE)
1039 insert_before = PREV_INSN (insert_before);
1042 insert_before = insn;
1044 emit_insn_before (gen_move_insn (replacements->new,
1049 replacements = replacements->next;
1053 /* Also fix up any invalid exprs in the REG_NOTES of this insn.
1054 But don't touch other insns referred to by reg-notes;
1055 we will get them elsewhere. */
1056 for (note = REG_NOTES (insn); note; note = XEXP (note, 1))
1057 if (GET_CODE (note) != INSN_LIST)
1058 XEXP (note, 0) = walk_fixup_memory_subreg (XEXP (note, 0), insn);
1064 /* VAR is a MEM that used to be a pseudo register. See if the rtx expression
1065 at *LOC in INSN needs to be changed.
1067 REPLACEMENTS is a pointer to a list head that starts out zero, but may
1068 contain a list of original rtx's and replacements. If we find that we need
1069 to modify this insn by replacing a memory reference with a pseudo or by
1070 making a new MEM to implement a SUBREG, we consult that list to see if
1071 we have already chosen a replacement. If none has already been allocated,
1072 we allocate it and update the list. fixup_var_refs_insns will copy VAR
1073 or the SUBREG, as appropriate, to the pseudo. */
1076 fixup_var_refs_1 (var, loc, insn, replacements)
1080 struct fixup_replacement **replacements;
1083 register rtx x = *loc;
1084 RTX_CODE code = GET_CODE (x);
1086 register rtx tem, tem1;
1087 struct fixup_replacement *replacement;
1094 /* If we already have a replacement, use it. Otherwise,
1095 try to fix up this address in case it is invalid. */
1097 replacement = find_replacement (replacements, var);
1098 if (replacement->new)
1100 *loc = replacement->new;
1104 *loc = replacement->new = x = fixup_stack_1 (x, insn);
1106 /* Unless we are forcing memory to register, we can leave things
1107 the way they are if the insn is valid. */
1109 INSN_CODE (insn) = -1;
1110 if (! flag_force_mem && recog_memoized (insn) >= 0)
1113 *loc = replacement->new = gen_reg_rtx (GET_MODE (x));
1117 /* If X contains VAR, we need to unshare it here so that we update
1118 each occurrence separately. But all identical MEMs in one insn
1119 must be replaced with the same rtx because of the possibility of
1122 if (reg_mentioned_p (var, x))
1124 replacement = find_replacement (replacements, x);
1125 if (replacement->new == 0)
1126 replacement->new = copy_most_rtx (x, var);
1128 *loc = x = replacement->new;
1144 /* Note that in some cases those types of expressions are altered
1145 by optimize_bit_field, and do not survive to get here. */
1146 if (XEXP (x, 0) == var
1147 || (GET_CODE (XEXP (x, 0)) == SUBREG
1148 && SUBREG_REG (XEXP (x, 0)) == var))
1150 /* Get TEM as a valid MEM in the mode presently in the insn.
1152 We don't worry about the possibility of MATCH_DUP here; it
1153 is highly unlikely and would be tricky to handle. */
1156 if (GET_CODE (tem) == SUBREG)
1157 tem = fixup_memory_subreg (tem, insn, 1);
1158 tem = fixup_stack_1 (tem, insn);
1160 /* Unless we want to load from memory, get TEM into the proper mode
1161 for an extract from memory. This can only be done if the
1162 extract is at a constant position and length. */
1164 if (! flag_force_mem && GET_CODE (XEXP (x, 1)) == CONST_INT
1165 && GET_CODE (XEXP (x, 2)) == CONST_INT
1166 && ! mode_dependent_address_p (XEXP (tem, 0))
1167 && ! MEM_VOLATILE_P (tem))
1169 enum machine_mode wanted_mode = VOIDmode;
1170 enum machine_mode is_mode = GET_MODE (tem);
1171 int width = INTVAL (XEXP (x, 1));
1172 int pos = INTVAL (XEXP (x, 2));
1175 if (GET_CODE (x) == ZERO_EXTRACT)
1176 wanted_mode = insn_operand_mode[(int) CODE_FOR_extzv][1];
1179 if (GET_CODE (x) == SIGN_EXTRACT)
1180 wanted_mode = insn_operand_mode[(int) CODE_FOR_extv][1];
1182 /* If we have a narrower mode, we can do something. */
1183 if (wanted_mode != VOIDmode
1184 && GET_MODE_SIZE (wanted_mode) < GET_MODE_SIZE (is_mode))
1186 int offset = pos / BITS_PER_UNIT;
1187 rtx old_pos = XEXP (x, 2);
1190 /* If the bytes and bits are counted differently, we
1191 must adjust the offset. */
1192 #if BYTES_BIG_ENDIAN != BITS_BIG_ENDIAN
1193 offset = (GET_MODE_SIZE (is_mode)
1194 - GET_MODE_SIZE (wanted_mode) - offset);
1197 pos %= GET_MODE_BITSIZE (wanted_mode);
1199 newmem = gen_rtx (MEM, wanted_mode,
1200 plus_constant (XEXP (tem, 0), offset));
1201 RTX_UNCHANGING_P (newmem) = RTX_UNCHANGING_P (tem);
1202 MEM_VOLATILE_P (newmem) = MEM_VOLATILE_P (tem);
1203 MEM_IN_STRUCT_P (newmem) = MEM_IN_STRUCT_P (tem);
1205 /* Make the change and see if the insn remains valid. */
1206 INSN_CODE (insn) = -1;
1207 XEXP (x, 0) = newmem;
1208 XEXP (x, 2) = gen_rtx (CONST_INT, VOIDmode, pos);
1210 if (recog_memoized (insn) >= 0)
1213 /* Otherwise, restore old position. XEXP (x, 0) will be
1215 XEXP (x, 2) = old_pos;
1219 /* If we get here, the bitfield extract insn can't accept a memory
1220 reference. Copy the input into a register. */
1222 tem1 = gen_reg_rtx (GET_MODE (tem));
1223 emit_insn_before (gen_move_insn (tem1, tem), insn);
1230 if (SUBREG_REG (x) == var)
1232 /* If this SUBREG makes VAR wider, it has become a paradoxical
1233 SUBREG with VAR in memory, but these aren't allowed at this
1234 stage of the compilation. So load VAR into a pseudo and take
1235 a SUBREG of that pseudo. */
1236 if (GET_MODE_SIZE (GET_MODE (x)) > GET_MODE_SIZE (GET_MODE (var)))
1238 replacement = find_replacement (replacements, var);
1239 if (replacement->new == 0)
1240 replacement->new = gen_reg_rtx (GET_MODE (var));
1241 SUBREG_REG (x) = replacement->new;
1245 /* See if we have already found a replacement for this SUBREG.
1246 If so, use it. Otherwise, make a MEM and see if the insn
1247 is recognized. If not, or if we should force MEM into a register,
1248 make a pseudo for this SUBREG. */
1249 replacement = find_replacement (replacements, x);
1250 if (replacement->new)
1252 *loc = replacement->new;
1256 replacement->new = *loc = fixup_memory_subreg (x, insn, 0);
1258 if (! flag_force_mem && recog_memoized (insn) >= 0)
1261 *loc = replacement->new = gen_reg_rtx (GET_MODE (x));
1267 /* First do special simplification of bit-field references. */
1268 if (GET_CODE (SET_DEST (x)) == SIGN_EXTRACT
1269 || GET_CODE (SET_DEST (x)) == ZERO_EXTRACT)
1270 optimize_bit_field (x, insn, 0);
1271 if (GET_CODE (SET_SRC (x)) == SIGN_EXTRACT
1272 || GET_CODE (SET_SRC (x)) == ZERO_EXTRACT)
1273 optimize_bit_field (x, insn, 0);
1275 /* If SET_DEST is now a paradoxical SUBREG, put the result of this
1276 insn into a pseudo and store the low part of the pseudo into VAR. */
1277 if (GET_CODE (SET_DEST (x)) == SUBREG
1278 && SUBREG_REG (SET_DEST (x)) == var
1279 && (GET_MODE_SIZE (GET_MODE (SET_DEST (x)))
1280 > GET_MODE_SIZE (GET_MODE (var))))
1282 SET_DEST (x) = tem = gen_reg_rtx (GET_MODE (SET_DEST (x)));
1283 emit_insn_after (gen_move_insn (var, gen_lowpart (GET_MODE (var),
1290 rtx dest = SET_DEST (x);
1291 rtx src = SET_SRC (x);
1292 rtx outerdest = dest;
1294 while (GET_CODE (dest) == SUBREG || GET_CODE (dest) == STRICT_LOW_PART
1295 || GET_CODE (dest) == SIGN_EXTRACT
1296 || GET_CODE (dest) == ZERO_EXTRACT)
1297 dest = XEXP (dest, 0);
1299 if (GET_CODE (src) == SUBREG)
1300 src = XEXP (src, 0);
1302 /* If VAR does not appear at the top level of the SET
1303 just scan the lower levels of the tree. */
1305 if (src != var && dest != var)
1308 /* We will need to rerecognize this insn. */
1309 INSN_CODE (insn) = -1;
1312 if (GET_CODE (outerdest) == ZERO_EXTRACT && dest == var)
1314 /* Since this case will return, ensure we fixup all the
1316 fixup_var_refs_1 (var, &XEXP (outerdest, 1), insn, replacements);
1317 fixup_var_refs_1 (var, &XEXP (outerdest, 2), insn, replacements);
1318 fixup_var_refs_1 (var, &SET_SRC (x), insn, replacements);
1320 tem = XEXP (outerdest, 0);
1322 /* Clean up (SUBREG:SI (MEM:mode ...) 0)
1323 that may appear inside a ZERO_EXTRACT.
1324 This was legitimate when the MEM was a REG. */
1325 if (GET_CODE (tem) == SUBREG
1326 && SUBREG_REG (tem) == var)
1327 tem = fixup_memory_subreg (tem, insn, 1);
1329 tem = fixup_stack_1 (tem, insn);
1331 if (GET_CODE (XEXP (outerdest, 1)) == CONST_INT
1332 && GET_CODE (XEXP (outerdest, 2)) == CONST_INT
1333 && ! mode_dependent_address_p (XEXP (tem, 0))
1334 && ! MEM_VOLATILE_P (tem))
1336 enum machine_mode wanted_mode
1337 = insn_operand_mode[(int) CODE_FOR_insv][0];
1338 enum machine_mode is_mode = GET_MODE (tem);
1339 int width = INTVAL (XEXP (outerdest, 1));
1340 int pos = INTVAL (XEXP (outerdest, 2));
1342 /* If we have a narrower mode, we can do something. */
1343 if (GET_MODE_SIZE (wanted_mode) < GET_MODE_SIZE (is_mode))
1345 int offset = pos / BITS_PER_UNIT;
1346 rtx old_pos = XEXP (outerdest, 2);
1349 #if BYTES_BIG_ENDIAN != BITS_BIG_ENDIAN
1350 offset = (GET_MODE_SIZE (is_mode)
1351 - GET_MODE_SIZE (wanted_mode) - offset);
1354 pos %= GET_MODE_BITSIZE (wanted_mode);
1356 newmem = gen_rtx (MEM, wanted_mode,
1357 plus_constant (XEXP (tem, 0), offset));
1358 RTX_UNCHANGING_P (newmem) = RTX_UNCHANGING_P (tem);
1359 MEM_VOLATILE_P (newmem) = MEM_VOLATILE_P (tem);
1360 MEM_IN_STRUCT_P (newmem) = MEM_IN_STRUCT_P (tem);
1362 /* Make the change and see if the insn remains valid. */
1363 INSN_CODE (insn) = -1;
1364 XEXP (outerdest, 0) = newmem;
1365 XEXP (outerdest, 2) = gen_rtx (CONST_INT, VOIDmode, pos);
1367 if (recog_memoized (insn) >= 0)
1370 /* Otherwise, restore old position. XEXP (x, 0) will be
1372 XEXP (outerdest, 2) = old_pos;
1376 /* If we get here, the bit-field store doesn't allow memory
1377 or isn't located at a constant position. Load the value into
1378 a register, do the store, and put it back into memory. */
1380 tem1 = gen_reg_rtx (GET_MODE (tem));
1381 emit_insn_before (gen_move_insn (tem1, tem), insn);
1382 emit_insn_after (gen_move_insn (tem, tem1), insn);
1383 XEXP (outerdest, 0) = tem1;
1388 /* STRICT_LOW_PART is a no-op on memory references
1389 and it can cause combinations to be unrecognizable,
1392 if (dest == var && GET_CODE (SET_DEST (x)) == STRICT_LOW_PART)
1393 SET_DEST (x) = XEXP (SET_DEST (x), 0);
1395 /* A valid insn to copy VAR into or out of a register
1396 must be left alone, to avoid an infinite loop here.
1397 If the reference to VAR is by a subreg, fix that up,
1398 since SUBREG is not valid for a memref.
1399 Also fix up the address of the stack slot. */
1401 if ((SET_SRC (x) == var
1402 || (GET_CODE (SET_SRC (x)) == SUBREG
1403 && SUBREG_REG (SET_SRC (x)) == var))
1404 && (GET_CODE (SET_DEST (x)) == REG
1405 || (GET_CODE (SET_DEST (x)) == SUBREG
1406 && GET_CODE (SUBREG_REG (SET_DEST (x))) == REG))
1407 && recog_memoized (insn) >= 0)
1409 replacement = find_replacement (replacements, SET_SRC (x));
1410 if (replacement->new)
1412 SET_SRC (x) = replacement->new;
1415 else if (GET_CODE (SET_SRC (x)) == SUBREG)
1416 SET_SRC (x) = replacement->new
1417 = fixup_memory_subreg (SET_SRC (x), insn, 0);
1419 SET_SRC (x) = replacement->new
1420 = fixup_stack_1 (SET_SRC (x), insn);
1424 if ((SET_DEST (x) == var
1425 || (GET_CODE (SET_DEST (x)) == SUBREG
1426 && SUBREG_REG (SET_DEST (x)) == var))
1427 && (GET_CODE (SET_SRC (x)) == REG
1428 || (GET_CODE (SET_SRC (x)) == SUBREG
1429 && GET_CODE (SUBREG_REG (SET_SRC (x))) == REG))
1430 && recog_memoized (insn) >= 0)
1432 if (GET_CODE (SET_DEST (x)) == SUBREG)
1433 SET_DEST (x) = fixup_memory_subreg (SET_DEST (x), insn, 0);
1435 SET_DEST (x) = fixup_stack_1 (SET_DEST (x), insn);
1439 /* Otherwise, storing into VAR must be handled specially
1440 by storing into a temporary and copying that into VAR
1441 with a new insn after this one. */
1448 /* STRICT_LOW_PART can be discarded, around a MEM. */
1449 if (GET_CODE (tem) == STRICT_LOW_PART)
1450 tem = XEXP (tem, 0);
1451 /* Convert (SUBREG (MEM)) to a MEM in a changed mode. */
1452 if (GET_CODE (tem) == SUBREG)
1453 fixeddest = fixup_memory_subreg (tem, insn, 0);
1455 fixeddest = fixup_stack_1 (tem, insn);
1457 temp = gen_reg_rtx (GET_MODE (tem));
1458 emit_insn_after (gen_move_insn (fixeddest, temp), insn);
1459 SET_DEST (x) = temp;
1464 /* Nothing special about this RTX; fix its operands. */
1466 fmt = GET_RTX_FORMAT (code);
1467 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1470 fixup_var_refs_1 (var, &XEXP (x, i), insn, replacements);
1474 for (j = 0; j < XVECLEN (x, i); j++)
1475 fixup_var_refs_1 (var, &XVECEXP (x, i, j), insn, replacements);
1480 /* Given X, an rtx of the form (SUBREG:m1 (MEM:m2 addr)),
1481 return an rtx (MEM:m1 newaddr) which is equivalent.
1482 If any insns must be emitted to compute NEWADDR, put them before INSN.
1484 UNCRITICAL nonzero means accept paradoxical subregs.
1485 This is used for subregs found inside of ZERO_EXTRACTs. */
1488 fixup_memory_subreg (x, insn, uncritical)
1493 int offset = SUBREG_WORD (x) * UNITS_PER_WORD;
1494 rtx addr = XEXP (SUBREG_REG (x), 0);
1495 enum machine_mode mode = GET_MODE (x);
1498 /* Paradoxical SUBREGs are usually invalid during RTL generation. */
1499 if (GET_MODE_SIZE (mode) > GET_MODE_SIZE (GET_MODE (SUBREG_REG (x)))
1503 #if BYTES_BIG_ENDIAN
1504 offset += (MIN (UNITS_PER_WORD, GET_MODE_SIZE (GET_MODE (SUBREG_REG (x))))
1505 - MIN (UNITS_PER_WORD, GET_MODE_SIZE (mode)));
1507 addr = plus_constant (addr, offset);
1508 if (!flag_force_addr && memory_address_p (mode, addr))
1509 /* Shortcut if no insns need be emitted. */
1510 return change_address (SUBREG_REG (x), mode, addr);
1512 result = change_address (SUBREG_REG (x), mode, addr);
1513 emit_insn_before (gen_sequence (), insn);
1518 /* Do fixup_memory_subreg on all (SUBREG (MEM ...) ...) contained in X.
1519 Replace subexpressions of X in place.
1520 If X itself is a (SUBREG (MEM ...) ...), return the replacement expression.
1521 Otherwise return X, with its contents possibly altered.
1523 If any insns must be emitted to compute NEWADDR, put them before INSN. */
1526 walk_fixup_memory_subreg (x, insn)
1530 register enum rtx_code code;
1537 code = GET_CODE (x);
1539 if (code == SUBREG && GET_CODE (SUBREG_REG (x)) == MEM)
1540 return fixup_memory_subreg (x, insn, 0);
1542 /* Nothing special about this RTX; fix its operands. */
1544 fmt = GET_RTX_FORMAT (code);
1545 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1548 XEXP (x, i) = walk_fixup_memory_subreg (XEXP (x, i), insn);
1552 for (j = 0; j < XVECLEN (x, i); j++)
1554 = walk_fixup_memory_subreg (XVECEXP (x, i, j), insn);
1561 /* Fix up any references to stack slots that are invalid memory addresses
1562 because they exceed the maximum range of a displacement. */
1565 fixup_stack_slots ()
1569 /* Did we generate a stack slot that is out of range
1570 or otherwise has an invalid address? */
1571 if (invalid_stack_slot)
1573 /* Yes. Must scan all insns for stack-refs that exceed the limit. */
1574 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
1575 if (GET_CODE (insn) == INSN || GET_CODE (insn) == CALL_INSN
1576 || GET_CODE (insn) == JUMP_INSN)
1577 fixup_stack_1 (PATTERN (insn), insn);
1582 /* For each memory ref within X, if it refers to a stack slot
1583 with an out of range displacement, put the address in a temp register
1584 (emitting new insns before INSN to load these registers)
1585 and alter the memory ref to use that register.
1586 Replace each such MEM rtx with a copy, to avoid clobberage. */
1589 fixup_stack_1 (x, insn)
1594 register RTX_CODE code = GET_CODE (x);
1599 register rtx ad = XEXP (x, 0);
1600 /* If we have address of a stack slot but it's not valid
1601 (displacement is too large), compute the sum in a register. */
1602 if (GET_CODE (ad) == PLUS
1603 && GET_CODE (XEXP (ad, 0)) == REG
1604 && REGNO (XEXP (ad, 0)) >= FIRST_VIRTUAL_REGISTER
1605 && REGNO (XEXP (ad, 0)) <= LAST_VIRTUAL_REGISTER
1606 && GET_CODE (XEXP (ad, 1)) == CONST_INT)
1609 if (memory_address_p (GET_MODE (x), ad))
1613 temp = copy_to_reg (ad);
1614 seq = gen_sequence ();
1616 emit_insn_before (seq, insn);
1617 return change_address (x, VOIDmode, temp);
1622 fmt = GET_RTX_FORMAT (code);
1623 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1626 XEXP (x, i) = fixup_stack_1 (XEXP (x, i), insn);
1630 for (j = 0; j < XVECLEN (x, i); j++)
1631 XVECEXP (x, i, j) = fixup_stack_1 (XVECEXP (x, i, j), insn);
1637 /* Optimization: a bit-field instruction whose field
1638 happens to be a byte or halfword in memory
1639 can be changed to a move instruction.
1641 We call here when INSN is an insn to examine or store into a bit-field.
1642 BODY is the SET-rtx to be altered.
1644 EQUIV_MEM is the table `reg_equiv_mem' if that is available; else 0.
1645 (Currently this is called only from function.c, and EQUIV_MEM
1649 optimize_bit_field (body, insn, equiv_mem)
1654 register rtx bitfield;
1657 enum machine_mode mode;
1659 if (GET_CODE (SET_DEST (body)) == SIGN_EXTRACT
1660 || GET_CODE (SET_DEST (body)) == ZERO_EXTRACT)
1661 bitfield = SET_DEST (body), destflag = 1;
1663 bitfield = SET_SRC (body), destflag = 0;
1665 /* First check that the field being stored has constant size and position
1666 and is in fact a byte or halfword suitably aligned. */
1668 if (GET_CODE (XEXP (bitfield, 1)) == CONST_INT
1669 && GET_CODE (XEXP (bitfield, 2)) == CONST_INT
1670 && ((mode = mode_for_size (INTVAL (XEXP (bitfield, 1)), MODE_INT, 1))
1672 && INTVAL (XEXP (bitfield, 2)) % INTVAL (XEXP (bitfield, 1)) == 0)
1674 register rtx memref = 0;
1676 /* Now check that the containing word is memory, not a register,
1677 and that it is safe to change the machine mode. */
1679 if (GET_CODE (XEXP (bitfield, 0)) == MEM)
1680 memref = XEXP (bitfield, 0);
1681 else if (GET_CODE (XEXP (bitfield, 0)) == REG
1683 memref = equiv_mem[REGNO (XEXP (bitfield, 0))];
1684 else if (GET_CODE (XEXP (bitfield, 0)) == SUBREG
1685 && GET_CODE (SUBREG_REG (XEXP (bitfield, 0))) == MEM)
1686 memref = SUBREG_REG (XEXP (bitfield, 0));
1687 else if (GET_CODE (XEXP (bitfield, 0)) == SUBREG
1689 && GET_CODE (SUBREG_REG (XEXP (bitfield, 0))) == REG)
1690 memref = equiv_mem[REGNO (SUBREG_REG (XEXP (bitfield, 0)))];
1693 && ! mode_dependent_address_p (XEXP (memref, 0))
1694 && ! MEM_VOLATILE_P (memref))
1696 /* Now adjust the address, first for any subreg'ing
1697 that we are now getting rid of,
1698 and then for which byte of the word is wanted. */
1700 register int offset = INTVAL (XEXP (bitfield, 2));
1701 /* Adjust OFFSET to count bits from low-address byte. */
1702 #if BITS_BIG_ENDIAN != BYTES_BIG_ENDIAN
1703 offset = (GET_MODE_BITSIZE (GET_MODE (XEXP (bitfield, 0)))
1704 - offset - INTVAL (XEXP (bitfield, 1)));
1706 /* Adjust OFFSET to count bytes from low-address byte. */
1707 offset /= BITS_PER_UNIT;
1708 if (GET_CODE (XEXP (bitfield, 0)) == SUBREG)
1710 offset += SUBREG_WORD (XEXP (bitfield, 0)) * UNITS_PER_WORD;
1711 #if BYTES_BIG_ENDIAN
1712 offset -= (MIN (UNITS_PER_WORD,
1713 GET_MODE_SIZE (GET_MODE (XEXP (bitfield, 0))))
1714 - MIN (UNITS_PER_WORD,
1715 GET_MODE_SIZE (GET_MODE (memref))));
1719 memref = change_address (memref, mode,
1720 plus_constant (XEXP (memref, 0), offset));
1722 /* Store this memory reference where
1723 we found the bit field reference. */
1727 validate_change (insn, &SET_DEST (body), memref, 1);
1728 if (! CONSTANT_ADDRESS_P (SET_SRC (body)))
1730 rtx src = SET_SRC (body);
1731 while (GET_CODE (src) == SUBREG
1732 && SUBREG_WORD (src) == 0)
1733 src = SUBREG_REG (src);
1734 if (GET_MODE (src) != GET_MODE (memref))
1735 src = gen_lowpart (GET_MODE (memref), SET_SRC (body));
1736 validate_change (insn, &SET_SRC (body), src, 1);
1738 else if (GET_MODE (SET_SRC (body)) != VOIDmode
1739 && GET_MODE (SET_SRC (body)) != GET_MODE (memref))
1740 /* This shouldn't happen because anything that didn't have
1741 one of these modes should have got converted explicitly
1742 and then referenced through a subreg.
1743 This is so because the original bit-field was
1744 handled by agg_mode and so its tree structure had
1745 the same mode that memref now has. */
1750 rtx dest = SET_DEST (body);
1752 while (GET_CODE (dest) == SUBREG
1753 && SUBREG_WORD (dest) == 0)
1754 dest = SUBREG_REG (dest);
1756 validate_change (insn, &SET_DEST (body), dest, 1);
1758 if (GET_MODE (dest) == GET_MODE (memref))
1759 validate_change (insn, &SET_SRC (body), memref, 1);
1762 /* Convert the mem ref to the destination mode. */
1763 rtx newreg = gen_reg_rtx (GET_MODE (dest));
1766 convert_move (newreg, memref,
1767 GET_CODE (SET_SRC (body)) == ZERO_EXTRACT);
1771 validate_change (insn, &SET_SRC (body), newreg, 1);
1775 /* See if we can convert this extraction or insertion into
1776 a simple move insn. We might not be able to do so if this
1777 was, for example, part of a PARALLEL.
1779 If we succeed, write out any needed conversions. If we fail,
1780 it is hard to guess why we failed, so don't do anything
1781 special; just let the optimization be suppressed. */
1783 if (apply_change_group () && seq)
1784 emit_insns_before (seq, insn);
1789 /* These routines are responsible for converting virtual register references
1790 to the actual hard register references once RTL generation is complete.
1792 The following four variables are used for communication between the
1793 routines. They contain the offsets of the virtual registers from their
1794 respective hard registers. */
1796 static int in_arg_offset;
1797 static int var_offset;
1798 static int dynamic_offset;
1799 static int out_arg_offset;
1801 /* In most machines, the stack pointer register is equivalent to the bottom
1804 #ifndef STACK_POINTER_OFFSET
1805 #define STACK_POINTER_OFFSET 0
1808 /* If not defined, pick an appropriate default for the offset of dynamically
1809 allocated memory depending on the value of ACCUMULATE_OUTGOING_ARGS,
1810 REG_PARM_STACK_SPACE, and OUTGOING_REG_PARM_STACK_SPACE. */
1812 #ifndef STACK_DYNAMIC_OFFSET
1814 #ifdef ACCUMULATE_OUTGOING_ARGS
1815 /* The bottom of the stack points to the actual arguments. If
1816 REG_PARM_STACK_SPACE is defined, this includes the space for the register
1817 parameters. However, if OUTGOING_REG_PARM_STACK space is not defined,
1818 stack space for register parameters is not pushed by the caller, but
1819 rather part of the fixed stack areas and hence not included in
1820 `current_function_outgoing_args_size'. Nevertheless, we must allow
1821 for it when allocating stack dynamic objects. */
1823 #if defined(REG_PARM_STACK_SPACE) && ! defined(OUTGOING_REG_PARM_STACK_SPACE)
1824 #define STACK_DYNAMIC_OFFSET(FNDECL) \
1825 (current_function_outgoing_args_size \
1826 + REG_PARM_STACK_SPACE (FNDECL) + (STACK_POINTER_OFFSET))
1829 #define STACK_DYNAMIC_OFFSET(FNDECL) \
1830 (current_function_outgoing_args_size + (STACK_POINTER_OFFSET))
1834 #define STACK_DYNAMIC_OFFSET(FNDECL) STACK_POINTER_OFFSET
1838 /* Pass through the INSNS of function FNDECL and convert virtual register
1839 references to hard register references. */
1842 instantiate_virtual_regs (fndecl, insns)
1848 /* Compute the offsets to use for this function. */
1849 in_arg_offset = FIRST_PARM_OFFSET (fndecl);
1850 var_offset = STARTING_FRAME_OFFSET;
1851 dynamic_offset = STACK_DYNAMIC_OFFSET (fndecl);
1852 out_arg_offset = STACK_POINTER_OFFSET;
1854 /* Scan all variables and parameters of this function. For each that is
1855 in memory, instantiate all virtual registers if the result is a valid
1856 address. If not, we do it later. That will handle most uses of virtual
1857 regs on many machines. */
1858 instantiate_decls (fndecl, 1);
1860 /* Initialize recognition, indicating that volatile is OK. */
1863 /* Scan through all the insns, instantiating every virtual register still
1865 for (insn = insns; insn; insn = NEXT_INSN (insn))
1866 if (GET_CODE (insn) == INSN || GET_CODE (insn) == JUMP_INSN
1867 || GET_CODE (insn) == CALL_INSN)
1869 instantiate_virtual_regs_1 (&PATTERN (insn), insn, 1);
1870 instantiate_virtual_regs_1 (®_NOTES (insn), 0, 0);
1873 /* Now instantiate the remaining register equivalences for debugging info.
1874 These will not be valid addresses. */
1875 instantiate_decls (fndecl, 0);
1877 /* Indicate that, from now on, assign_stack_local should use
1878 frame_pointer_rtx. */
1879 virtuals_instantiated = 1;
1882 /* Scan all decls in FNDECL (both variables and parameters) and instantiate
1883 all virtual registers in their DECL_RTL's.
1885 If VALID_ONLY, do this only if the resulting address is still valid.
1886 Otherwise, always do it. */
1889 instantiate_decls (fndecl, valid_only)
1895 if (TREE_INLINE (fndecl))
1896 /* When compiling an inline function, the obstack used for
1897 rtl allocation is the maybepermanent_obstack. Calling
1898 `resume_temporary_allocation' switches us back to that
1899 obstack while we process this function's parameters. */
1900 resume_temporary_allocation ();
1902 /* Process all parameters of the function. */
1903 for (decl = DECL_ARGUMENTS (fndecl); decl; decl = TREE_CHAIN (decl))
1905 if (DECL_RTL (decl) && GET_CODE (DECL_RTL (decl)) == MEM)
1906 instantiate_virtual_regs_1 (&XEXP (DECL_RTL (decl), 0),
1907 valid_only ? DECL_RTL (decl) : 0, 0);
1908 #if 1 /* This is probably correct, but it seems to require fixes
1909 elsewhere in order to work. Let's fix them in 2.1. */
1910 if (DECL_INCOMING_RTL (decl)
1911 && GET_CODE (DECL_INCOMING_RTL (decl)) == MEM)
1912 instantiate_virtual_regs_1 (&XEXP (DECL_INCOMING_RTL (decl), 0),
1913 valid_only ? DECL_INCOMING_RTL (decl) : 0,
1918 /* Now process all variables defined in the function or its subblocks. */
1919 instantiate_decls_1 (DECL_INITIAL (fndecl), valid_only);
1921 if (TREE_INLINE (fndecl))
1923 /* Save all rtl allocated for this function by raising the
1924 high-water mark on the maybepermanent_obstack. */
1926 /* All further rtl allocation is now done in the current_obstack. */
1927 rtl_in_current_obstack ();
1931 /* Subroutine of instantiate_decls: Process all decls in the given
1932 BLOCK node and all its subblocks. */
1935 instantiate_decls_1 (let, valid_only)
1941 for (t = BLOCK_VARS (let); t; t = TREE_CHAIN (t))
1942 if (DECL_RTL (t) && GET_CODE (DECL_RTL (t)) == MEM)
1943 instantiate_virtual_regs_1 (& XEXP (DECL_RTL (t), 0),
1944 valid_only ? DECL_RTL (t) : 0, 0);
1946 /* Process all subblocks. */
1947 for (t = BLOCK_SUBBLOCKS (let); t; t = TREE_CHAIN (t))
1948 instantiate_decls_1 (t, valid_only);
1951 /* Given a pointer to a piece of rtx and an optional pointer to the
1952 containing object, instantiate any virtual registers present in it.
1954 If EXTRA_INSNS, we always do the replacement and generate
1955 any extra insns before OBJECT. If it zero, we do nothing if replacement
1958 Return 1 if we either had nothing to do or if we were able to do the
1959 needed replacement. Return 0 otherwise; we only return zero if
1960 EXTRA_INSNS is zero.
1962 We first try some simple transformations to avoid the creation of extra
1966 instantiate_virtual_regs_1 (loc, object, extra_insns)
1980 /* Re-start here to avoid recursion in common cases. */
1987 code = GET_CODE (x);
1989 /* Check for some special cases. */
2006 /* We are allowed to set the virtual registers. This means that
2007 that the actual register should receive the source minus the
2008 appropriate offset. This is used, for example, in the handling
2009 of non-local gotos. */
2010 if (SET_DEST (x) == virtual_incoming_args_rtx)
2011 new = arg_pointer_rtx, offset = - in_arg_offset;
2012 else if (SET_DEST (x) == virtual_stack_vars_rtx)
2013 new = frame_pointer_rtx, offset = - var_offset;
2014 else if (SET_DEST (x) == virtual_stack_dynamic_rtx)
2015 new = stack_pointer_rtx, offset = - dynamic_offset;
2016 else if (SET_DEST (x) == virtual_outgoing_args_rtx)
2017 new = stack_pointer_rtx, offset = - out_arg_offset;
2021 /* The only valid sources here are PLUS or REG. Just do
2022 the simplest possible thing to handle them. */
2023 if (GET_CODE (SET_SRC (x)) != REG
2024 && GET_CODE (SET_SRC (x)) != PLUS)
2028 if (GET_CODE (SET_SRC (x)) != REG)
2029 temp = force_operand (SET_SRC (x), 0);
2032 temp = force_operand (plus_constant (temp, offset), 0);
2036 emit_insns_before (seq, object);
2039 if (!validate_change (object, &SET_SRC (x), temp, 0)
2046 instantiate_virtual_regs_1 (&SET_DEST (x), object, extra_insns);
2051 /* Handle special case of virtual register plus constant. */
2052 if (CONSTANT_P (XEXP (x, 1)))
2056 /* Check for (plus (plus VIRT foo) (const_int)) first. */
2057 if (GET_CODE (XEXP (x, 0)) == PLUS)
2059 rtx inner = XEXP (XEXP (x, 0), 0);
2061 if (inner == virtual_incoming_args_rtx)
2062 new = arg_pointer_rtx, offset = in_arg_offset;
2063 else if (inner == virtual_stack_vars_rtx)
2064 new = frame_pointer_rtx, offset = var_offset;
2065 else if (inner == virtual_stack_dynamic_rtx)
2066 new = stack_pointer_rtx, offset = dynamic_offset;
2067 else if (inner == virtual_outgoing_args_rtx)
2068 new = stack_pointer_rtx, offset = out_arg_offset;
2075 instantiate_virtual_regs_1 (&XEXP (XEXP (x, 0), 1), object,
2077 new = gen_rtx (PLUS, Pmode, new, XEXP (XEXP (x, 0), 1));
2080 else if (XEXP (x, 0) == virtual_incoming_args_rtx)
2081 new = arg_pointer_rtx, offset = in_arg_offset;
2082 else if (XEXP (x, 0) == virtual_stack_vars_rtx)
2083 new = frame_pointer_rtx, offset = var_offset;
2084 else if (XEXP (x, 0) == virtual_stack_dynamic_rtx)
2085 new = stack_pointer_rtx, offset = dynamic_offset;
2086 else if (XEXP (x, 0) == virtual_outgoing_args_rtx)
2087 new = stack_pointer_rtx, offset = out_arg_offset;
2090 /* We know the second operand is a constant. Unless the
2091 first operand is a REG (which has been already checked),
2092 it needs to be checked. */
2093 if (GET_CODE (XEXP (x, 0)) != REG)
2103 new = plus_constant (XEXP (x, 1), offset);
2105 /* If the new constant is zero, try to replace the sum with its
2107 if (new == const0_rtx
2108 && validate_change (object, loc, XEXP (x, 0), 0))
2111 /* Next try to replace constant with new one. */
2112 if (!validate_change (object, &XEXP (x, 1), new, 0))
2120 /* Otherwise copy the new constant into a register and replace
2121 constant with that register. */
2122 temp = gen_reg_rtx (Pmode);
2123 if (validate_change (object, &XEXP (x, 1), temp, 0))
2124 emit_insn_before (gen_move_insn (temp, new), object);
2127 /* If that didn't work, replace this expression with a
2128 register containing the sum. */
2130 new = gen_rtx (PLUS, Pmode, XEXP (x, 0), new);
2134 temp = force_operand (new, 0);
2138 emit_insns_before (seq, object);
2139 if (! validate_change (object, loc, temp, 0)
2140 && ! validate_replace_rtx (x, temp, object))
2148 /* Fall through to generic two-operand expression case. */
2154 case DIV: case UDIV:
2155 case MOD: case UMOD:
2156 case AND: case IOR: case XOR:
2157 case LSHIFT: case ASHIFT: case ROTATE:
2158 case ASHIFTRT: case LSHIFTRT: case ROTATERT:
2160 case GE: case GT: case GEU: case GTU:
2161 case LE: case LT: case LEU: case LTU:
2162 if (XEXP (x, 1) && ! CONSTANT_P (XEXP (x, 1)))
2163 instantiate_virtual_regs_1 (&XEXP (x, 1), object, extra_insns);
2168 /* Most cases of MEM that convert to valid addresses have already been
2169 handled by our scan of regno_reg_rtx. The only special handling we
2170 need here is to make a copy of the rtx to ensure it isn't being
2171 shared if we have to change it to a pseudo.
2173 If the rtx is a simple reference to an address via a virtual register,
2174 it can potentially be shared. In such cases, first try to make it
2175 a valid address, which can also be shared. Otherwise, copy it and
2178 First check for common cases that need no processing. These are
2179 usually due to instantiation already being done on a previous instance
2183 if (CONSTANT_ADDRESS_P (temp)
2184 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2185 || temp == arg_pointer_rtx
2187 || temp == frame_pointer_rtx)
2190 if (GET_CODE (temp) == PLUS
2191 && CONSTANT_ADDRESS_P (XEXP (temp, 1))
2192 && (XEXP (temp, 0) == frame_pointer_rtx
2193 #if FRAME_POINTER_REGNUM != ARG_POINTER_REGNUM
2194 || XEXP (temp, 0) == arg_pointer_rtx
2199 if (temp == virtual_stack_vars_rtx
2200 || temp == virtual_incoming_args_rtx
2201 || (GET_CODE (temp) == PLUS
2202 && CONSTANT_ADDRESS_P (XEXP (temp, 1))
2203 && (XEXP (temp, 0) == virtual_stack_vars_rtx
2204 || XEXP (temp, 0) == virtual_incoming_args_rtx)))
2206 /* This MEM may be shared. If the substitution can be done without
2207 the need to generate new pseudos, we want to do it in place
2208 so all copies of the shared rtx benefit. The call below will
2209 only make substitutions if the resulting address is still
2212 Note that we cannot pass X as the object in the recursive call
2213 since the insn being processed may not allow all valid
2214 addresses. However, if we were not passed on object, we can
2215 only modify X without copying it if X will have a valid
2218 ??? Also note that this can still lose if OBJECT is an insn that
2219 has less restrictions on an address that some other insn.
2220 In that case, we will modify the shared address. This case
2221 doesn't seem very likely, though. */
2223 if (instantiate_virtual_regs_1 (&XEXP (x, 0),
2224 object ? object : x, 0))
2227 /* Otherwise make a copy and process that copy. We copy the entire
2228 RTL expression since it might be a PLUS which could also be
2230 *loc = x = copy_rtx (x);
2233 /* Fall through to generic unary operation case. */
2237 case STRICT_LOW_PART:
2239 case PRE_DEC: case PRE_INC: case POST_DEC: case POST_INC:
2240 case SIGN_EXTEND: case ZERO_EXTEND:
2241 case TRUNCATE: case FLOAT_EXTEND: case FLOAT_TRUNCATE:
2242 case FLOAT: case FIX:
2243 case UNSIGNED_FIX: case UNSIGNED_FLOAT:
2247 /* These case either have just one operand or we know that we need not
2248 check the rest of the operands. */
2253 /* Try to replace with a PLUS. If that doesn't work, compute the sum
2254 in front of this insn and substitute the temporary. */
2255 if (x == virtual_incoming_args_rtx)
2256 new = arg_pointer_rtx, offset = in_arg_offset;
2257 else if (x == virtual_stack_vars_rtx)
2258 new = frame_pointer_rtx, offset = var_offset;
2259 else if (x == virtual_stack_dynamic_rtx)
2260 new = stack_pointer_rtx, offset = dynamic_offset;
2261 else if (x == virtual_outgoing_args_rtx)
2262 new = stack_pointer_rtx, offset = out_arg_offset;
2266 temp = plus_constant (new, offset);
2267 if (!validate_change (object, loc, temp, 0))
2273 temp = force_operand (temp, 0);
2277 emit_insns_before (seq, object);
2278 if (! validate_change (object, loc, temp, 0)
2279 && ! validate_replace_rtx (x, temp, object))
2287 /* Scan all subexpressions. */
2288 fmt = GET_RTX_FORMAT (code);
2289 for (i = 0; i < GET_RTX_LENGTH (code); i++, fmt++)
2292 if (!instantiate_virtual_regs_1 (&XEXP (x, i), object, extra_insns))
2295 else if (*fmt == 'E')
2296 for (j = 0; j < XVECLEN (x, i); j++)
2297 if (! instantiate_virtual_regs_1 (&XVECEXP (x, i, j), object,
2304 /* Optimization: assuming this function does not receive nonlocal gotos,
2305 delete the handlers for such, as well as the insns to establish
2306 and disestablish them. */
2312 for (insn = get_insns (); insn; insn = NEXT_INSN (insn))
2314 /* Delete the handler by turning off the flag that would
2315 prevent jump_optimize from deleting it.
2316 Also permit deletion of the nonlocal labels themselves
2317 if nothing local refers to them. */
2318 if (GET_CODE (insn) == CODE_LABEL)
2319 LABEL_PRESERVE_P (insn) = 0;
2320 if (GET_CODE (insn) == INSN
2321 && ((nonlocal_goto_handler_slot != 0
2322 && reg_mentioned_p (nonlocal_goto_handler_slot, PATTERN (insn)))
2323 || (nonlocal_goto_stack_level != 0
2324 && reg_mentioned_p (nonlocal_goto_stack_level,
2330 /* Return a list (chain of EXPR_LIST nodes) for the nonlocal labels
2331 of the current function. */
2334 nonlocal_label_rtx_list ()
2339 for (t = nonlocal_labels; t; t = TREE_CHAIN (t))
2340 x = gen_rtx (EXPR_LIST, VOIDmode, label_rtx (TREE_VALUE (t)), x);
2345 /* Output a USE for any register use in RTL.
2346 This is used with -noreg to mark the extent of lifespan
2347 of any registers used in a user-visible variable's DECL_RTL. */
2353 if (GET_CODE (rtl) == REG)
2354 /* This is a register variable. */
2355 emit_insn (gen_rtx (USE, VOIDmode, rtl));
2356 else if (GET_CODE (rtl) == MEM
2357 && GET_CODE (XEXP (rtl, 0)) == REG
2358 && (REGNO (XEXP (rtl, 0)) < FIRST_VIRTUAL_REGISTER
2359 || REGNO (XEXP (rtl, 0)) > LAST_VIRTUAL_REGISTER)
2360 && XEXP (rtl, 0) != current_function_internal_arg_pointer)
2361 /* This is a variable-sized structure. */
2362 emit_insn (gen_rtx (USE, VOIDmode, XEXP (rtl, 0)));
2365 /* Like use_variable except that it outputs the USEs after INSN
2366 instead of at the end of the insn-chain. */
2369 use_variable_after (rtl, insn)
2372 if (GET_CODE (rtl) == REG)
2373 /* This is a register variable. */
2374 emit_insn_after (gen_rtx (USE, VOIDmode, rtl), insn);
2375 else if (GET_CODE (rtl) == MEM
2376 && GET_CODE (XEXP (rtl, 0)) == REG
2377 && (REGNO (XEXP (rtl, 0)) < FIRST_VIRTUAL_REGISTER
2378 || REGNO (XEXP (rtl, 0)) > LAST_VIRTUAL_REGISTER)
2379 && XEXP (rtl, 0) != current_function_internal_arg_pointer)
2380 /* This is a variable-sized structure. */
2381 emit_insn_after (gen_rtx (USE, VOIDmode, XEXP (rtl, 0)), insn);
2387 return max_parm_reg;
2390 /* Return the first insn following those generated by `assign_parms'. */
2393 get_first_nonparm_insn ()
2396 return NEXT_INSN (last_parm_insn);
2397 return get_insns ();
2400 /* Return 1 if EXP returns an aggregate value, for which an address
2401 must be passed to the function or returned by the function. */
2404 aggregate_value_p (exp)
2407 if (TYPE_MODE (TREE_TYPE (exp)) == BLKmode)
2409 if (RETURN_IN_MEMORY (TREE_TYPE (exp)))
2411 if (flag_pcc_struct_return
2412 && (TREE_CODE (TREE_TYPE (exp)) == RECORD_TYPE
2413 || TREE_CODE (TREE_TYPE (exp)) == UNION_TYPE))
2418 /* Assign RTL expressions to the function's parameters.
2419 This may involve copying them into registers and using
2420 those registers as the RTL for them.
2422 If SECOND_TIME is non-zero it means that this function is being
2423 called a second time. This is done by integrate.c when a function's
2424 compilation is deferred. We need to come back here in case the
2425 FUNCTION_ARG macro computes items needed for the rest of the compilation
2426 (such as changing which registers are fixed or caller-saved). But suppress
2427 writing any insns or setting DECL_RTL of anything in this case. */
2430 assign_parms (fndecl, second_time)
2435 register rtx entry_parm = 0;
2436 register rtx stack_parm = 0;
2437 CUMULATIVE_ARGS args_so_far;
2438 enum machine_mode passed_mode, nominal_mode;
2439 /* Total space needed so far for args on the stack,
2440 given as a constant and a tree-expression. */
2441 struct args_size stack_args_size;
2442 tree fntype = TREE_TYPE (fndecl);
2443 tree fnargs = DECL_ARGUMENTS (fndecl);
2444 /* This is used for the arg pointer when referring to stack args. */
2445 rtx internal_arg_pointer;
2446 /* This is a dummy PARM_DECL that we used for the function result if
2447 the function returns a structure. */
2448 tree function_result_decl = 0;
2449 int nparmregs = list_length (fnargs) + LAST_VIRTUAL_REGISTER + 1;
2450 int varargs_setup = 0;
2452 /* Nonzero if the last arg is named `__builtin_va_alist',
2453 which is used on some machines for old-fashioned non-ANSI varargs.h;
2454 this should be stuck onto the stack as if it had arrived there. */
2457 && (parm = tree_last (fnargs)) != 0
2459 && (! strcmp (IDENTIFIER_POINTER (DECL_NAME (parm)),
2460 "__builtin_va_alist")));
2462 /* Nonzero if function takes extra anonymous args.
2463 This means the last named arg must be on the stack
2464 right before the anonymous ones. */
2466 = (TYPE_ARG_TYPES (fntype) != 0
2467 && (TREE_VALUE (tree_last (TYPE_ARG_TYPES (fntype)))
2468 != void_type_node));
2470 /* If the reg that the virtual arg pointer will be translated into is
2471 not a fixed reg or is the stack pointer, make a copy of the virtual
2472 arg pointer, and address parms via the copy. The frame pointer is
2473 considered fixed even though it is not marked as such.
2475 The second time through, simply use ap to avoid generating rtx. */
2477 if ((ARG_POINTER_REGNUM == STACK_POINTER_REGNUM
2478 || ! (fixed_regs[ARG_POINTER_REGNUM]
2479 || ARG_POINTER_REGNUM == FRAME_POINTER_REGNUM))
2481 internal_arg_pointer = copy_to_reg (virtual_incoming_args_rtx);
2483 internal_arg_pointer = virtual_incoming_args_rtx;
2484 current_function_internal_arg_pointer = internal_arg_pointer;
2486 stack_args_size.constant = 0;
2487 stack_args_size.var = 0;
2489 /* If struct value address is treated as the first argument, make it so. */
2490 if (aggregate_value_p (DECL_RESULT (fndecl))
2491 && ! current_function_returns_pcc_struct
2492 && struct_value_incoming_rtx == 0)
2494 tree type = build_pointer_type (fntype);
2496 function_result_decl = build_decl (PARM_DECL, 0, type);
2498 DECL_ARG_TYPE (function_result_decl) = type;
2499 TREE_CHAIN (function_result_decl) = fnargs;
2500 fnargs = function_result_decl;
2503 parm_reg_stack_loc = (rtx *) oballoc (nparmregs * sizeof (rtx));
2504 bzero (parm_reg_stack_loc, nparmregs * sizeof (rtx));
2506 #ifdef INIT_CUMULATIVE_INCOMING_ARGS
2507 INIT_CUMULATIVE_INCOMING_ARGS (args_so_far, fntype, 0);
2509 INIT_CUMULATIVE_ARGS (args_so_far, fntype, 0);
2512 /* We haven't yet found an argument that we must push and pretend the
2514 current_function_pretend_args_size = 0;
2516 for (parm = fnargs; parm; parm = TREE_CHAIN (parm))
2519 = (TREE_CODE (TREE_TYPE (parm)) == ARRAY_TYPE
2520 || TREE_CODE (TREE_TYPE (parm)) == RECORD_TYPE
2521 || TREE_CODE (TREE_TYPE (parm)) == UNION_TYPE);
2522 struct args_size stack_offset;
2523 struct args_size arg_size;
2524 int passed_pointer = 0;
2525 tree passed_type = DECL_ARG_TYPE (parm);
2527 /* Set LAST_NAMED if this is last named arg before some
2528 anonymous args. We treat it as if it were anonymous too. */
2529 int last_named = ((TREE_CHAIN (parm) == 0
2530 || DECL_NAME (TREE_CHAIN (parm)) == 0)
2531 && (vararg || stdarg));
2533 if (TREE_TYPE (parm) == error_mark_node
2534 /* This can happen after weird syntax errors
2535 or if an enum type is defined among the parms. */
2536 || TREE_CODE (parm) != PARM_DECL
2537 || passed_type == NULL)
2539 DECL_RTL (parm) = gen_rtx (MEM, BLKmode, const0_rtx);
2540 TREE_USED (parm) = 1;
2544 /* For varargs.h function, save info about regs and stack space
2545 used by the individual args, not including the va_alist arg. */
2546 if (vararg && last_named)
2547 current_function_args_info = args_so_far;
2549 /* Find mode of arg as it is passed, and mode of arg
2550 as it should be during execution of this function. */
2551 passed_mode = TYPE_MODE (passed_type);
2552 nominal_mode = TYPE_MODE (TREE_TYPE (parm));
2554 #ifdef FUNCTION_ARG_PASS_BY_REFERENCE
2555 /* See if this arg was passed by invisible reference. */
2556 if (FUNCTION_ARG_PASS_BY_REFERENCE (args_so_far, passed_mode,
2557 passed_type, ! last_named))
2559 passed_type = build_pointer_type (passed_type);
2561 passed_mode = nominal_mode = Pmode;
2565 /* Let machine desc say which reg (if any) the parm arrives in.
2566 0 means it arrives on the stack. */
2567 #ifdef FUNCTION_INCOMING_ARG
2568 entry_parm = FUNCTION_INCOMING_ARG (args_so_far, passed_mode,
2569 passed_type, ! last_named);
2571 entry_parm = FUNCTION_ARG (args_so_far, passed_mode,
2572 passed_type, ! last_named);
2575 #ifdef SETUP_INCOMING_VARARGS
2576 /* If this is the last named parameter, do any required setup for
2577 varargs or stdargs. We need to know about the case of this being an
2578 addressable type, in which case we skip the registers it
2579 would have arrived in.
2581 For stdargs, LAST_NAMED will be set for two parameters, the one that
2582 is actually the last named, and the dummy parameter. We only
2583 want to do this action once.
2585 Also, indicate when RTL generation is to be suppressed. */
2586 if (last_named && !varargs_setup)
2588 SETUP_INCOMING_VARARGS (args_so_far, passed_mode, passed_type,
2589 current_function_pretend_args_size,
2595 /* Determine parm's home in the stack,
2596 in case it arrives in the stack or we should pretend it did.
2598 Compute the stack position and rtx where the argument arrives
2601 There is one complexity here: If this was a parameter that would
2602 have been passed in registers, but wasn't only because it is
2603 __builtin_va_alist, we want locate_and_pad_parm to treat it as if
2604 it came in a register so that REG_PARM_STACK_SPACE isn't skipped.
2605 In this case, we call FUNCTION_ARG with NAMED set to 1 instead of
2606 0 as it was the previous time. */
2608 locate_and_pad_parm (passed_mode, passed_type,
2609 #ifdef STACK_PARMS_IN_REG_PARM_AREA
2612 #ifdef FUNCTION_INCOMING_ARG
2613 FUNCTION_INCOMING_ARG (args_so_far, passed_mode,
2616 || varargs_setup)) != 0,
2618 FUNCTION_ARG (args_so_far, passed_mode,
2620 ! last_named || varargs_setup) != 0,
2623 fndecl, &stack_args_size, &stack_offset, &arg_size);
2627 rtx offset_rtx = ARGS_SIZE_RTX (stack_offset);
2629 if (offset_rtx == const0_rtx)
2630 stack_parm = gen_rtx (MEM, passed_mode, internal_arg_pointer);
2632 stack_parm = gen_rtx (MEM, passed_mode,
2633 gen_rtx (PLUS, Pmode,
2634 internal_arg_pointer, offset_rtx));
2636 /* If this is a memory ref that contains aggregate components,
2637 mark it as such for cse and loop optimize. */
2638 MEM_IN_STRUCT_P (stack_parm) = aggregate;
2641 /* If this parameter was passed both in registers and in the stack,
2642 use the copy on the stack. */
2643 if (MUST_PASS_IN_STACK (passed_mode, passed_type))
2646 /* If this parm was passed part in regs and part in memory,
2647 pretend it arrived entirely in memory
2648 by pushing the register-part onto the stack.
2650 In the special case of a DImode or DFmode that is split,
2651 we could put it together in a pseudoreg directly,
2652 but for now that's not worth bothering with. */
2657 #ifdef FUNCTION_ARG_PARTIAL_NREGS
2658 nregs = FUNCTION_ARG_PARTIAL_NREGS (args_so_far, passed_mode,
2659 passed_type, ! last_named);
2664 current_function_pretend_args_size
2665 = (((nregs * UNITS_PER_WORD) + (PARM_BOUNDARY / BITS_PER_UNIT) - 1)
2666 / (PARM_BOUNDARY / BITS_PER_UNIT)
2667 * (PARM_BOUNDARY / BITS_PER_UNIT));
2670 move_block_from_reg (REGNO (entry_parm),
2671 validize_mem (stack_parm), nregs);
2672 entry_parm = stack_parm;
2676 /* If we didn't decide this parm came in a register,
2677 by default it came on the stack. */
2678 if (entry_parm == 0)
2679 entry_parm = stack_parm;
2681 /* Record permanently how this parm was passed. */
2683 DECL_INCOMING_RTL (parm) = entry_parm;
2685 /* If there is actually space on the stack for this parm,
2686 count it in stack_args_size; otherwise set stack_parm to 0
2687 to indicate there is no preallocated stack slot for the parm. */
2689 if (entry_parm == stack_parm
2690 #if defined (REG_PARM_STACK_SPACE) && ! defined (MAYBE_REG_PARM_STACK_SPACE)
2691 /* On some machines, even if a parm value arrives in a register
2692 there is still an (uninitialized) stack slot allocated for it.
2694 ??? When MAYBE_REG_PARM_STACK_SPACE is defined, we can't tell
2695 whether this parameter already has a stack slot allocated,
2696 because an arg block exists only if current_function_args_size
2697 is larger than some threshhold, and we haven't calculated that
2698 yet. So, for now, we just assume that stack slots never exist
2700 || REG_PARM_STACK_SPACE (fndecl) > 0
2704 stack_args_size.constant += arg_size.constant;
2706 ADD_PARM_SIZE (stack_args_size, arg_size.var);
2709 /* No stack slot was pushed for this parm. */
2712 /* Update info on where next arg arrives in registers. */
2714 FUNCTION_ARG_ADVANCE (args_so_far, passed_mode,
2715 passed_type, ! last_named);
2717 /* If this is our second time through, we are done with this parm. */
2721 /* If we can't trust the parm stack slot to be aligned enough
2722 for its ultimate type, don't use that slot after entry.
2723 We'll make another stack slot, if we need one. */
2725 #ifdef FUNCTION_ARG_BOUNDARY
2726 int thisparm_boundary
2727 = FUNCTION_ARG_BOUNDARY (passed_mode, passed_type);
2729 int thisparm_boundary = PARM_BOUNDARY;
2732 if (GET_MODE_ALIGNMENT (nominal_mode) > thisparm_boundary)
2736 /* Now adjust STACK_PARM to the mode and precise location
2737 where this parameter should live during execution,
2738 if we discover that it must live in the stack during execution.
2739 To make debuggers happier on big-endian machines, we store
2740 the value in the last bytes of the space available. */
2742 if (nominal_mode != BLKmode && nominal_mode != passed_mode
2747 #if BYTES_BIG_ENDIAN
2748 if (GET_MODE_SIZE (nominal_mode) < UNITS_PER_WORD)
2749 stack_offset.constant += (GET_MODE_SIZE (passed_mode)
2750 - GET_MODE_SIZE (nominal_mode));
2753 offset_rtx = ARGS_SIZE_RTX (stack_offset);
2754 if (offset_rtx == const0_rtx)
2755 stack_parm = gen_rtx (MEM, nominal_mode, internal_arg_pointer);
2757 stack_parm = gen_rtx (MEM, nominal_mode,
2758 gen_rtx (PLUS, Pmode,
2759 internal_arg_pointer, offset_rtx));
2761 /* If this is a memory ref that contains aggregate components,
2762 mark it as such for cse and loop optimize. */
2763 MEM_IN_STRUCT_P (stack_parm) = aggregate;
2766 /* ENTRY_PARM is an RTX for the parameter as it arrives,
2767 in the mode in which it arrives.
2768 STACK_PARM is an RTX for a stack slot where the parameter can live
2769 during the function (in case we want to put it there).
2770 STACK_PARM is 0 if no stack slot was pushed for it.
2772 Now output code if necessary to convert ENTRY_PARM to
2773 the type in which this function declares it,
2774 and store that result in an appropriate place,
2775 which may be a pseudo reg, may be STACK_PARM,
2776 or may be a local stack slot if STACK_PARM is 0.
2778 Set DECL_RTL to that place. */
2780 if (nominal_mode == BLKmode)
2782 /* If a BLKmode arrives in registers, copy it to a stack slot. */
2783 if (GET_CODE (entry_parm) == REG)
2785 int size_stored = CEIL_ROUND (int_size_in_bytes (TREE_TYPE (parm)),
2788 /* Note that we will be storing an integral number of words.
2789 So we have to be careful to ensure that we allocate an
2790 integral number of words. We do this below in the
2791 assign_stack_local if space was not allocated in the argument
2792 list. If it was, this will not work if PARM_BOUNDARY is not
2793 a multiple of BITS_PER_WORD. It isn't clear how to fix this
2794 if it becomes a problem. */
2796 if (stack_parm == 0)
2798 = assign_stack_local (GET_MODE (entry_parm), size_stored, 0);
2799 else if (PARM_BOUNDARY % BITS_PER_WORD != 0)
2802 move_block_from_reg (REGNO (entry_parm),
2803 validize_mem (stack_parm),
2804 size_stored / UNITS_PER_WORD);
2806 DECL_RTL (parm) = stack_parm;
2809 #if 0 /* This change was turned off because it makes compilation bigger. */
2811 #else /* It's not clear why the following was replaced. */
2812 /* Obsoleted by preceding line. */
2813 (obey_regdecls && ! TREE_REGDECL (parm)
2814 && ! TREE_INLINE (fndecl))
2816 /* layout_decl may set this. */
2817 || TREE_ADDRESSABLE (parm)
2818 || TREE_SIDE_EFFECTS (parm)
2819 /* If -ffloat-store specified, don't put explicit
2820 float variables into registers. */
2821 || (flag_float_store
2822 && TREE_CODE (TREE_TYPE (parm)) == REAL_TYPE))
2823 /* Always assign pseudo to structure return or item passed
2824 by invisible reference. */
2825 || passed_pointer || parm == function_result_decl)
2827 /* Store the parm in a pseudoregister during the function. */
2828 register rtx parmreg = gen_reg_rtx (nominal_mode);
2830 REG_USERVAR_P (parmreg) = 1;
2832 /* If this was an item that we received a pointer to, set DECL_RTL
2836 DECL_RTL (parm) = gen_rtx (MEM, TYPE_MODE (TREE_TYPE (passed_type)), parmreg);
2837 MEM_IN_STRUCT_P (DECL_RTL (parm)) = aggregate;
2840 DECL_RTL (parm) = parmreg;
2842 /* Copy the value into the register. */
2843 if (GET_MODE (parmreg) != GET_MODE (entry_parm))
2845 /* If ENTRY_PARM is a hard register, it might be in a register
2846 not valid for operating in its mode (e.g., an odd-numbered
2847 register for a DFmode). In that case, moves are the only
2848 thing valid, so we can't do a convert from there. This
2849 occurs when the calling sequence allow such misaligned
2851 if (GET_CODE (entry_parm) == REG
2852 && REGNO (entry_parm) < FIRST_PSEUDO_REGISTER
2853 && ! HARD_REGNO_MODE_OK (REGNO (entry_parm),
2854 GET_MODE (entry_parm)))
2855 convert_move (parmreg, copy_to_reg (entry_parm));
2857 convert_move (parmreg, validize_mem (entry_parm), 0);
2860 emit_move_insn (parmreg, validize_mem (entry_parm));
2862 /* In any case, record the parm's desired stack location
2863 in case we later discover it must live in the stack. */
2864 if (REGNO (parmreg) >= nparmregs)
2867 nparmregs = REGNO (parmreg) + 5;
2868 new = (rtx *) oballoc (nparmregs * sizeof (rtx));
2869 bcopy (parm_reg_stack_loc, new, nparmregs * sizeof (rtx));
2870 parm_reg_stack_loc = new;
2872 parm_reg_stack_loc[REGNO (parmreg)] = stack_parm;
2874 /* Mark the register as eliminable if we did no conversion
2875 and it was copied from memory at a fixed offset,
2876 and the arg pointer was not copied to a pseudo-reg.
2877 If the arg pointer is a pseudo reg or the offset formed
2878 an invalid address, such memory-equivalences
2879 as we make here would screw up life analysis for it. */
2880 if (nominal_mode == passed_mode
2881 && GET_CODE (entry_parm) == MEM
2882 && entry_parm == stack_parm
2883 && stack_offset.var == 0
2884 && reg_mentioned_p (virtual_incoming_args_rtx,
2885 XEXP (entry_parm, 0)))
2886 REG_NOTES (get_last_insn ())
2887 = gen_rtx (EXPR_LIST, REG_EQUIV,
2888 entry_parm, REG_NOTES (get_last_insn ()));
2890 /* For pointer data type, suggest pointer register. */
2891 if (TREE_CODE (TREE_TYPE (parm)) == POINTER_TYPE)
2892 mark_reg_pointer (parmreg);
2896 /* Value must be stored in the stack slot STACK_PARM
2897 during function execution. */
2899 if (passed_mode != nominal_mode)
2901 /* Conversion is required. */
2902 if (GET_CODE (entry_parm) == REG
2903 && REGNO (entry_parm) < FIRST_PSEUDO_REGISTER
2904 && ! HARD_REGNO_MODE_OK (REGNO (entry_parm), passed_mode))
2905 entry_parm = copy_to_reg (entry_parm);
2907 entry_parm = convert_to_mode (nominal_mode, entry_parm, 0);
2910 if (entry_parm != stack_parm)
2912 if (stack_parm == 0)
2913 stack_parm = assign_stack_local (GET_MODE (entry_parm),
2914 GET_MODE_SIZE (GET_MODE (entry_parm)), 0);
2915 emit_move_insn (validize_mem (stack_parm),
2916 validize_mem (entry_parm));
2919 DECL_RTL (parm) = stack_parm;
2922 /* If this "parameter" was the place where we are receiving the
2923 function's incoming structure pointer, set up the result. */
2924 if (parm == function_result_decl)
2925 DECL_RTL (DECL_RESULT (fndecl))
2926 = gen_rtx (MEM, DECL_MODE (DECL_RESULT (fndecl)), DECL_RTL (parm));
2928 if (TREE_THIS_VOLATILE (parm))
2929 MEM_VOLATILE_P (DECL_RTL (parm)) = 1;
2930 if (TREE_READONLY (parm))
2931 RTX_UNCHANGING_P (DECL_RTL (parm)) = 1;
2934 max_parm_reg = max_reg_num ();
2935 last_parm_insn = get_last_insn ();
2937 current_function_args_size = stack_args_size.constant;
2939 /* Adjust function incoming argument size for alignment and
2942 #ifdef REG_PARM_STACK_SPACE
2943 #ifndef MAYBE_REG_PARM_STACK_SPACE
2944 current_function_args_size = MAX (current_function_args_size,
2945 REG_PARM_STACK_SPACE (fndecl));
2949 #ifdef STACK_BOUNDARY
2950 #define STACK_BYTES (STACK_BOUNDARY / BITS_PER_UNIT)
2952 current_function_args_size
2953 = ((current_function_args_size + STACK_BYTES - 1)
2954 / STACK_BYTES) * STACK_BYTES;
2957 #ifdef ARGS_GROW_DOWNWARD
2958 current_function_arg_offset_rtx
2959 = (stack_args_size.var == 0 ? gen_rtx (CONST_INT, VOIDmode,
2960 -stack_args_size.constant)
2961 : expand_expr (size_binop (MINUS_EXPR, stack_args_size.var,
2962 size_int (-stack_args_size.constant)),
2965 current_function_arg_offset_rtx = ARGS_SIZE_RTX (stack_args_size);
2968 /* See how many bytes, if any, of its args a function should try to pop
2971 current_function_pops_args = RETURN_POPS_ARGS (TREE_TYPE (fndecl),
2972 current_function_args_size);
2974 /* For stdarg.h function, save info about regs and stack space
2975 used by the named args. */
2978 current_function_args_info = args_so_far;
2980 /* Set the rtx used for the function return value. Put this in its
2981 own variable so any optimizers that need this information don't have
2982 to include tree.h. Do this here so it gets done when an inlined
2983 function gets output. */
2985 current_function_return_rtx = DECL_RTL (DECL_RESULT (fndecl));
2988 /* Compute the size and offset from the start of the stacked arguments for a
2989 parm passed in mode PASSED_MODE and with type TYPE.
2991 INITIAL_OFFSET_PTR points to the current offset into the stacked
2994 The starting offset and size for this parm are returned in *OFFSET_PTR
2995 and *ARG_SIZE_PTR, respectively.
2997 IN_REGS is non-zero if the argument will be passed in registers. It will
2998 never be set if REG_PARM_STACK_SPACE is not defined.
3000 FNDECL is the function in which the argument was defined.
3002 There are two types of rounding that are done. The first, controlled by
3003 FUNCTION_ARG_BOUNDARY, forces the offset from the start of the argument
3004 list to be aligned to the specific boundary (in bits). This rounding
3005 affects the initial and starting offsets, but not the argument size.
3007 The second, controlled by FUNCTION_ARG_PADDING and PARM_BOUNDARY,
3008 optionally rounds the size of the parm to PARM_BOUNDARY. The
3009 initial offset is not affected by this rounding, while the size always
3010 is and the starting offset may be. */
3012 /* offset_ptr will be negative for ARGS_GROW_DOWNWARD case;
3013 initial_offset_ptr is positive because locate_and_pad_parm's
3014 callers pass in the total size of args so far as
3015 initial_offset_ptr. arg_size_ptr is always positive.*/
3017 static void pad_to_arg_alignment (), pad_below ();
3020 locate_and_pad_parm (passed_mode, type, in_regs, fndecl,
3021 initial_offset_ptr, offset_ptr, arg_size_ptr)
3022 enum machine_mode passed_mode;
3026 struct args_size *initial_offset_ptr;
3027 struct args_size *offset_ptr;
3028 struct args_size *arg_size_ptr;
3031 = type ? size_in_bytes (type) : size_int (GET_MODE_SIZE (passed_mode));
3032 enum direction where_pad = FUNCTION_ARG_PADDING (passed_mode, type);
3033 int boundary = FUNCTION_ARG_BOUNDARY (passed_mode, type);
3034 int boundary_in_bytes = boundary / BITS_PER_UNIT;
3035 int reg_parm_stack_space = 0;
3037 #ifdef REG_PARM_STACK_SPACE
3038 /* If we have found a stack parm before we reach the end of the
3039 area reserved for registers, skip that area. */
3042 #ifdef MAYBE_REG_PARM_STACK_SPACE
3043 reg_parm_stack_space = MAYBE_REG_PARM_STACK_SPACE;
3045 reg_parm_stack_space = REG_PARM_STACK_SPACE (fndecl);
3047 if (reg_parm_stack_space > 0)
3049 if (initial_offset_ptr->var)
3051 initial_offset_ptr->var
3052 = size_binop (MAX_EXPR, ARGS_SIZE_TREE (*initial_offset_ptr),
3053 size_int (reg_parm_stack_space));
3054 initial_offset_ptr->constant = 0;
3056 else if (initial_offset_ptr->constant < reg_parm_stack_space)
3057 initial_offset_ptr->constant = reg_parm_stack_space;
3060 #endif /* REG_PARM_STACK_SPACE */
3062 arg_size_ptr->var = 0;
3063 arg_size_ptr->constant = 0;
3065 #ifdef ARGS_GROW_DOWNWARD
3066 if (initial_offset_ptr->var)
3068 offset_ptr->constant = 0;
3069 offset_ptr->var = size_binop (MINUS_EXPR, integer_zero_node,
3070 initial_offset_ptr->var);
3074 offset_ptr->constant = - initial_offset_ptr->constant;
3075 offset_ptr->var = 0;
3077 if (where_pad == upward
3078 && (TREE_CODE (sizetree) != INTEGER_CST
3079 || ((TREE_INT_CST_LOW (sizetree) * BITS_PER_UNIT) % PARM_BOUNDARY)))
3080 sizetree = round_up (sizetree, PARM_BOUNDARY / BITS_PER_UNIT);
3081 SUB_PARM_SIZE (*offset_ptr, sizetree);
3082 pad_to_arg_alignment (offset_ptr, boundary);
3083 if (initial_offset_ptr->var)
3085 arg_size_ptr->var = size_binop (MINUS_EXPR,
3086 size_binop (MINUS_EXPR,
3088 initial_offset_ptr->var),
3093 arg_size_ptr->constant = (- initial_offset_ptr->constant -
3094 offset_ptr->constant);
3096 /* ADD_PARM_SIZE (*arg_size_ptr, sizetree); */
3097 if (where_pad == downward)
3098 pad_below (arg_size_ptr, passed_mode, sizetree);
3099 #else /* !ARGS_GROW_DOWNWARD */
3100 pad_to_arg_alignment (initial_offset_ptr, boundary);
3101 *offset_ptr = *initial_offset_ptr;
3102 if (where_pad == downward)
3103 pad_below (offset_ptr, passed_mode, sizetree);
3105 #ifdef PUSH_ROUNDING
3106 if (passed_mode != BLKmode)
3107 sizetree = size_int (PUSH_ROUNDING (TREE_INT_CST_LOW (sizetree)));
3110 if (where_pad != none
3111 && (TREE_CODE (sizetree) != INTEGER_CST
3112 || ((TREE_INT_CST_LOW (sizetree) * BITS_PER_UNIT) % PARM_BOUNDARY)))
3113 sizetree = round_up (sizetree, PARM_BOUNDARY / BITS_PER_UNIT);
3115 ADD_PARM_SIZE (*arg_size_ptr, sizetree);
3116 #endif /* ARGS_GROW_DOWNWARD */
3119 /* Round the stack offset in *OFFSET_PTR up to a multiple of BOUNDARY.
3120 BOUNDARY is measured in bits, but must be a multiple of a storage unit. */
3123 pad_to_arg_alignment (offset_ptr, boundary)
3124 struct args_size *offset_ptr;
3127 int boundary_in_bytes = boundary / BITS_PER_UNIT;
3129 if (boundary > BITS_PER_UNIT)
3131 if (offset_ptr->var)
3134 #ifdef ARGS_GROW_DOWNWARD
3139 (ARGS_SIZE_TREE (*offset_ptr),
3140 boundary / BITS_PER_UNIT);
3141 offset_ptr->constant = 0; /*?*/
3144 offset_ptr->constant =
3145 #ifdef ARGS_GROW_DOWNWARD
3146 FLOOR_ROUND (offset_ptr->constant, boundary_in_bytes);
3148 CEIL_ROUND (offset_ptr->constant, boundary_in_bytes);
3154 pad_below (offset_ptr, passed_mode, sizetree)
3155 struct args_size *offset_ptr;
3156 enum machine_mode passed_mode;
3159 if (passed_mode != BLKmode)
3161 if (GET_MODE_BITSIZE (passed_mode) % PARM_BOUNDARY)
3162 offset_ptr->constant
3163 += (((GET_MODE_BITSIZE (passed_mode) + PARM_BOUNDARY - 1)
3164 / PARM_BOUNDARY * PARM_BOUNDARY / BITS_PER_UNIT)
3165 - GET_MODE_SIZE (passed_mode));
3169 if (TREE_CODE (sizetree) != INTEGER_CST
3170 || (TREE_INT_CST_LOW (sizetree) * BITS_PER_UNIT) % PARM_BOUNDARY)
3172 /* Round the size up to multiple of PARM_BOUNDARY bits. */
3173 tree s2 = round_up (sizetree, PARM_BOUNDARY / BITS_PER_UNIT);
3175 ADD_PARM_SIZE (*offset_ptr, s2);
3176 SUB_PARM_SIZE (*offset_ptr, sizetree);
3182 round_down (value, divisor)
3186 return size_binop (MULT_EXPR,
3187 size_binop (FLOOR_DIV_EXPR, value, size_int (divisor)),
3188 size_int (divisor));
3191 /* Walk the tree of blocks describing the binding levels within a function
3192 and warn about uninitialized variables.
3193 This is done after calling flow_analysis and before global_alloc
3194 clobbers the pseudo-regs to hard regs. */
3197 uninitialized_vars_warning (block)
3200 register tree decl, sub;
3201 for (decl = BLOCK_VARS (block); decl; decl = TREE_CHAIN (decl))
3203 if (TREE_CODE (decl) == VAR_DECL
3204 /* These warnings are unreliable for and aggregates
3205 because assigning the fields one by one can fail to convince
3206 flow.c that the entire aggregate was initialized.
3207 Unions are troublesome because members may be shorter. */
3208 && TREE_CODE (TREE_TYPE (decl)) != RECORD_TYPE
3209 && TREE_CODE (TREE_TYPE (decl)) != UNION_TYPE
3210 && TREE_CODE (TREE_TYPE (decl)) != ARRAY_TYPE
3211 && DECL_RTL (decl) != 0
3212 && GET_CODE (DECL_RTL (decl)) == REG
3213 && regno_uninitialized (REGNO (DECL_RTL (decl))))
3214 warning_with_decl (decl,
3215 "`%s' may be used uninitialized in this function");
3216 if (TREE_CODE (decl) == VAR_DECL
3217 && DECL_RTL (decl) != 0
3218 && GET_CODE (DECL_RTL (decl)) == REG
3219 && regno_clobbered_at_setjmp (REGNO (DECL_RTL (decl))))
3220 warning_with_decl (decl,
3221 "variable `%s' may be clobbered by `longjmp'");
3223 for (sub = BLOCK_SUBBLOCKS (block); sub; sub = TREE_CHAIN (sub))
3224 uninitialized_vars_warning (sub);
3227 /* Do the appropriate part of uninitialized_vars_warning
3228 but for arguments instead of local variables. */
3231 setjmp_args_warning (block)
3235 for (decl = DECL_ARGUMENTS (current_function_decl);
3236 decl; decl = TREE_CHAIN (decl))
3237 if (DECL_RTL (decl) != 0
3238 && GET_CODE (DECL_RTL (decl)) == REG
3239 && regno_clobbered_at_setjmp (REGNO (DECL_RTL (decl))))
3240 warning_with_decl (decl, "argument `%s' may be clobbered by `longjmp'");
3243 /* If this function call setjmp, put all vars into the stack
3244 unless they were declared `register'. */
3247 setjmp_protect (block)
3250 register tree decl, sub;
3251 for (decl = BLOCK_VARS (block); decl; decl = TREE_CHAIN (decl))
3252 if ((TREE_CODE (decl) == VAR_DECL
3253 || TREE_CODE (decl) == PARM_DECL)
3254 && DECL_RTL (decl) != 0
3255 && GET_CODE (DECL_RTL (decl)) == REG
3256 /* If this variable came from an inline function, it must be
3257 that it's life doesn't overlap the setjmp. If there was a
3258 setjmp in the function, it would already be in memory. We
3259 must exclude such variable because their DECL_RTL might be
3260 set to strange things such as virtual_stack_vars_rtx. */
3261 && ! DECL_FROM_INLINE (decl)
3263 #ifdef NON_SAVING_SETJMP
3264 /* If longjmp doesn't restore the registers,
3265 don't put anything in them. */
3269 ! TREE_REGDECL (decl)))
3270 put_var_into_stack (decl);
3271 for (sub = BLOCK_SUBBLOCKS (block); sub; sub = TREE_CHAIN (sub))
3272 setjmp_protect (sub);
3275 /* Like the previous function, but for args instead of local variables. */
3278 setjmp_protect_args ()
3280 register tree decl, sub;
3281 for (decl = DECL_ARGUMENTS (current_function_decl);
3282 decl; decl = TREE_CHAIN (decl))
3283 if ((TREE_CODE (decl) == VAR_DECL
3284 || TREE_CODE (decl) == PARM_DECL)
3285 && DECL_RTL (decl) != 0
3286 && GET_CODE (DECL_RTL (decl)) == REG
3288 /* If longjmp doesn't restore the registers,
3289 don't put anything in them. */
3290 #ifdef NON_SAVING_SETJMP
3294 ! TREE_REGDECL (decl)))
3295 put_var_into_stack (decl);
3298 /* Return the context-pointer register corresponding to DECL,
3299 or 0 if it does not need one. */
3302 lookup_static_chain (decl)
3305 tree context = decl_function_context (decl);
3311 /* We treat inline_function_decl as an alias for the current function
3312 because that is the inline function whose vars, types, etc.
3313 are being merged into the current function.
3314 See expand_inline_function. */
3315 if (context == current_function_decl || context == inline_function_decl)
3316 return virtual_stack_vars_rtx;
3318 for (link = context_display; link; link = TREE_CHAIN (link))
3319 if (TREE_PURPOSE (link) == context)
3320 return RTL_EXPR_RTL (TREE_VALUE (link));
3325 /* Convert a stack slot address ADDR for variable VAR
3326 (from a containing function)
3327 into an address valid in this function (using a static chain). */
3330 fix_lexical_addr (addr, var)
3336 tree context = decl_function_context (var);
3337 struct function *fp;
3340 /* If this is the present function, we need not do anything. */
3341 if (context == current_function_decl || context == inline_function_decl)
3344 for (fp = outer_function_chain; fp; fp = fp->next)
3345 if (fp->decl == context)
3351 /* Decode given address as base reg plus displacement. */
3352 if (GET_CODE (addr) == REG)
3353 basereg = addr, displacement = 0;
3354 else if (GET_CODE (addr) == PLUS && GET_CODE (XEXP (addr, 1)) == CONST_INT)
3355 basereg = XEXP (addr, 0), displacement = INTVAL (XEXP (addr, 1));
3359 /* We accept vars reached via the containing function's
3360 incoming arg pointer and via its stack variables pointer. */
3361 if (basereg == fp->internal_arg_pointer)
3363 /* If reached via arg pointer, get the arg pointer value
3364 out of that function's stack frame.
3366 There are two cases: If a separate ap is needed, allocate a
3367 slot in the outer function for it and dereference it that way.
3368 This is correct even if the real ap is actually a pseudo.
3369 Otherwise, just adjust the offset from the frame pointer to
3372 #ifdef NEED_SEPARATE_AP
3375 if (fp->arg_pointer_save_area == 0)
3376 fp->arg_pointer_save_area
3377 = assign_outer_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0, fp);
3379 addr = fix_lexical_addr (XEXP (fp->arg_pointer_save_area, 0), var);
3380 addr = memory_address (Pmode, addr);
3382 base = copy_to_reg (gen_rtx (MEM, Pmode, addr));
3384 displacement += (FIRST_PARM_OFFSET (context) - STARTING_FRAME_OFFSET);
3385 base = lookup_static_chain (var);
3389 else if (basereg == virtual_stack_vars_rtx)
3391 /* This is the same code as lookup_static_chain, duplicated here to
3392 avoid an extra call to decl_function_context. */
3395 for (link = context_display; link; link = TREE_CHAIN (link))
3396 if (TREE_PURPOSE (link) == context)
3398 base = RTL_EXPR_RTL (TREE_VALUE (link));
3406 /* Use same offset, relative to appropriate static chain or argument
3408 return plus_constant (base, displacement);
3411 /* Return the address of the trampoline for entering nested fn FUNCTION.
3412 If necessary, allocate a trampoline (in the stack frame)
3413 and emit rtl to initialize its contents (at entry to this function). */
3416 trampoline_address (function)
3422 struct function *fp;
3425 /* Find an existing trampoline and return it. */
3426 for (link = trampoline_list; link; link = TREE_CHAIN (link))
3427 if (TREE_PURPOSE (link) == function)
3428 return XEXP (RTL_EXPR_RTL (TREE_VALUE (link)), 0);
3429 for (fp = outer_function_chain; fp; fp = fp->next)
3430 for (link = fp->trampoline_list; link; link = TREE_CHAIN (link))
3431 if (TREE_PURPOSE (link) == function)
3433 tramp = fix_lexical_addr (XEXP (RTL_EXPR_RTL (TREE_VALUE (link)), 0),
3435 return round_trampoline_addr (tramp);
3438 /* None exists; we must make one. */
3440 /* Find the `struct function' for the function containing FUNCTION. */
3442 fn_context = decl_function_context (function);
3443 if (fn_context != current_function_decl)
3444 for (fp = outer_function_chain; fp; fp = fp->next)
3445 if (fp->decl == fn_context)
3448 /* Allocate run-time space for this trampoline
3449 (usually in the defining function's stack frame). */
3450 #ifdef ALLOCATE_TRAMPOLINE
3451 tramp = ALLOCATE_TRAMPOLINE (fp);
3453 /* If rounding needed, allocate extra space
3454 to ensure we have TRAMPOLINE_SIZE bytes left after rounding up. */
3455 #ifdef TRAMPOLINE_ALIGNMENT
3456 #define TRAMPOLINE_REAL_SIZE (TRAMPOLINE_SIZE + TRAMPOLINE_ALIGNMENT - 1)
3458 #define TRAMPOLINE_REAL_SIZE (TRAMPOLINE_SIZE)
3461 tramp = assign_outer_stack_local (BLKmode, TRAMPOLINE_REAL_SIZE, 0, fp);
3463 tramp = assign_stack_local (BLKmode, TRAMPOLINE_REAL_SIZE, 0);
3466 /* Record the trampoline for reuse and note it for later initialization
3467 by expand_function_end. */
3470 push_obstacks (fp->current_obstack, fp->function_maybepermanent_obstack);
3471 rtlexp = make_node (RTL_EXPR);
3472 RTL_EXPR_RTL (rtlexp) = tramp;
3473 fp->trampoline_list = tree_cons (function, rtlexp, fp->trampoline_list);
3478 /* Make the RTL_EXPR node temporary, not momentary, so that the
3479 trampoline_list doesn't become garbage. */
3480 int momentary = suspend_momentary ();
3481 rtlexp = make_node (RTL_EXPR);
3482 resume_momentary (momentary);
3484 RTL_EXPR_RTL (rtlexp) = tramp;
3485 trampoline_list = tree_cons (function, rtlexp, trampoline_list);
3488 tramp = fix_lexical_addr (XEXP (tramp, 0), function);
3489 return round_trampoline_addr (tramp);
3492 /* Given a trampoline address,
3493 round it to multiple of TRAMPOLINE_ALIGNMENT. */
3496 round_trampoline_addr (tramp)
3499 #ifdef TRAMPOLINE_ALIGNMENT
3500 /* Round address up to desired boundary. */
3501 rtx temp = gen_reg_rtx (Pmode);
3502 temp = expand_binop (Pmode, add_optab, tramp,
3503 gen_rtx (CONST_INT, VOIDmode, TRAMPOLINE_ALIGNMENT - 1),
3504 temp, 0, OPTAB_LIB_WIDEN);
3505 tramp = expand_binop (Pmode, and_optab, temp,
3506 gen_rtx (CONST_INT, VOIDmode, - TRAMPOLINE_ALIGNMENT),
3507 temp, 0, OPTAB_LIB_WIDEN);
3512 /* Generate RTL for the start of the function SUBR (a FUNCTION_DECL tree node)
3513 and initialize static variables for generating RTL for the statements
3517 init_function_start (subr, filename, line)
3524 init_stmt_for_function ();
3526 cse_not_expected = ! optimize;
3528 /* Caller save not needed yet. */
3529 caller_save_needed = 0;
3531 /* No stack slots have been made yet. */
3532 stack_slot_list = 0;
3534 /* There is no stack slot for handling nonlocal gotos. */
3535 nonlocal_goto_handler_slot = 0;
3536 nonlocal_goto_stack_level = 0;
3538 /* No labels have been declared for nonlocal use. */
3539 nonlocal_labels = 0;
3541 /* No function calls so far in this function. */
3542 function_call_count = 0;
3544 /* No parm regs have been allocated.
3545 (This is important for output_inline_function.) */
3546 max_parm_reg = LAST_VIRTUAL_REGISTER + 1;
3548 /* Initialize the RTL mechanism. */
3551 /* Initialize the queue of pending postincrement and postdecrements,
3552 and some other info in expr.c. */
3555 /* We haven't done register allocation yet. */
3558 init_const_rtx_hash_table ();
3560 current_function_name = (*decl_printable_name) (subr, &junk);
3562 /* Nonzero if this is a nested function that uses a static chain. */
3564 current_function_needs_context
3565 = (decl_function_context (current_function_decl) != 0);
3567 /* Set if a call to setjmp is seen. */
3568 current_function_calls_setjmp = 0;
3570 /* Set if a call to longjmp is seen. */
3571 current_function_calls_longjmp = 0;
3573 current_function_calls_alloca = 0;
3574 current_function_has_nonlocal_label = 0;
3575 current_function_contains_functions = 0;
3577 current_function_returns_pcc_struct = 0;
3578 current_function_returns_struct = 0;
3579 current_function_epilogue_delay_list = 0;
3580 current_function_uses_const_pool = 0;
3581 current_function_uses_pic_offset_table = 0;
3583 /* We have not yet needed to make a label to jump to for tail-recursion. */
3584 tail_recursion_label = 0;
3586 /* We haven't had a need to make a save area for ap yet. */
3588 arg_pointer_save_area = 0;
3590 /* No stack slots allocated yet. */
3593 /* No SAVE_EXPRs in this function yet. */
3596 /* No RTL_EXPRs in this function yet. */
3599 /* We have not allocated any temporaries yet. */
3601 temp_slot_level = 0;
3603 /* Within function body, compute a type's size as soon it is laid out. */
3604 immediate_size_expand++;
3606 init_pending_stack_adjust ();
3607 inhibit_defer_pop = 0;
3609 current_function_outgoing_args_size = 0;
3611 /* Initialize the insn lengths. */
3612 init_insn_lengths ();
3614 /* Prevent ever trying to delete the first instruction of a function.
3615 Also tell final how to output a linenum before the function prologue. */
3616 emit_line_note (filename, line);
3618 /* Make sure first insn is a note even if we don't want linenums.
3619 This makes sure the first insn will never be deleted.
3620 Also, final expects a note to appear there. */
3621 emit_note (0, NOTE_INSN_DELETED);
3623 /* Set flags used by final.c. */
3624 if (aggregate_value_p (DECL_RESULT (subr)))
3626 #ifdef PCC_STATIC_STRUCT_RETURN
3627 if (flag_pcc_struct_return)
3628 current_function_returns_pcc_struct = 1;
3631 current_function_returns_struct = 1;
3634 /* Warn if this value is an aggregate type,
3635 regardless of which calling convention we are using for it. */
3636 if (warn_aggregate_return
3637 && (TREE_CODE (TREE_TYPE (DECL_RESULT (subr))) == RECORD_TYPE
3638 || TREE_CODE (TREE_TYPE (DECL_RESULT (subr))) == UNION_TYPE
3639 || TREE_CODE (TREE_TYPE (DECL_RESULT (subr))) == ARRAY_TYPE))
3640 warning ("function returns an aggregate");
3642 current_function_returns_pointer
3643 = (TREE_CODE (TREE_TYPE (DECL_RESULT (subr))) == POINTER_TYPE);
3645 /* Indicate that we need to distinguish between the return value of the
3646 present function and the return value of a function being called. */
3647 rtx_equal_function_value_matters = 1;
3649 /* Indicate that we have not instantiated virtual registers yet. */
3650 virtuals_instantiated = 0;
3652 /* Indicate we have no need of a frame pointer yet. */
3653 frame_pointer_needed = 0;
3655 /* By default assume not varargs. */
3656 current_function_varargs = 0;
3659 /* Indicate that the current function uses extra args
3660 not explicitly mentioned in the argument list in any fashion. */
3665 current_function_varargs = 1;
3668 /* Expand a call to __main at the beginning of a possible main function. */
3671 expand_main_function ()
3673 #if !defined (INIT_SECTION_ASM_OP) || defined (INVOKE__main)
3674 emit_library_call (gen_rtx (SYMBOL_REF, Pmode, "__main"), 0,
3676 #endif /* not INIT_SECTION_ASM_OP or INVOKE__main */
3679 /* Start the RTL for a new function, and set variables used for
3681 SUBR is the FUNCTION_DECL node.
3682 PARMS_HAVE_CLEANUPS is nonzero if there are cleanups associated with
3683 the function's parameters, which must be run at any return statement. */
3686 expand_function_start (subr, parms_have_cleanups)
3688 int parms_have_cleanups;
3694 /* Make sure volatile mem refs aren't considered
3695 valid operands of arithmetic insns. */
3696 init_recog_no_volatile ();
3698 /* If function gets a static chain arg, store it in the stack frame.
3699 Do this first, so it gets the first stack slot offset. */
3700 if (current_function_needs_context)
3702 last_ptr = assign_stack_local (Pmode, GET_MODE_SIZE (Pmode), 0);
3703 emit_move_insn (last_ptr, static_chain_incoming_rtx);
3706 /* If the parameters of this function need cleaning up, get a label
3707 for the beginning of the code which executes those cleanups. This must
3708 be done before doing anything with return_label. */
3709 if (parms_have_cleanups)
3710 cleanup_label = gen_label_rtx ();
3714 /* Make the label for return statements to jump to, if this machine
3715 does not have a one-instruction return and uses an epilogue,
3716 or if it returns a structure, or if it has parm cleanups. */
3718 if (cleanup_label == 0 && HAVE_return
3719 && ! current_function_returns_pcc_struct
3720 && ! (current_function_returns_struct && ! optimize))
3723 return_label = gen_label_rtx ();
3725 return_label = gen_label_rtx ();
3728 /* Initialize rtx used to return the value. */
3729 /* Do this before assign_parms so that we copy the struct value address
3730 before any library calls that assign parms might generate. */
3732 /* Decide whether to return the value in memory or in a register. */
3733 if (aggregate_value_p (DECL_RESULT (subr)))
3735 /* Returning something that won't go in a register. */
3736 register rtx value_address;
3738 #ifdef PCC_STATIC_STRUCT_RETURN
3739 if (current_function_returns_pcc_struct)
3741 int size = int_size_in_bytes (TREE_TYPE (DECL_RESULT (subr)));
3742 value_address = assemble_static_space (size);
3747 /* Expect to be passed the address of a place to store the value.
3748 If it is passed as an argument, assign_parms will take care of
3750 if (struct_value_incoming_rtx)
3752 value_address = gen_reg_rtx (Pmode);
3753 emit_move_insn (value_address, struct_value_incoming_rtx);
3757 DECL_RTL (DECL_RESULT (subr))
3758 = gen_rtx (MEM, DECL_MODE (DECL_RESULT (subr)),
3761 else if (DECL_MODE (DECL_RESULT (subr)) == VOIDmode)
3762 /* If return mode is void, this decl rtl should not be used. */
3763 DECL_RTL (DECL_RESULT (subr)) = 0;
3764 else if (parms_have_cleanups)
3765 /* If function will end with cleanup code for parms,
3766 compute the return values into a pseudo reg,
3767 which we will copy into the true return register
3768 after the cleanups are done. */
3769 DECL_RTL (DECL_RESULT (subr))
3770 = gen_reg_rtx (DECL_MODE (DECL_RESULT (subr)));
3772 /* Scalar, returned in a register. */
3774 #ifdef FUNCTION_OUTGOING_VALUE
3775 DECL_RTL (DECL_RESULT (subr))
3776 = FUNCTION_OUTGOING_VALUE (TREE_TYPE (DECL_RESULT (subr)), subr);
3778 DECL_RTL (DECL_RESULT (subr))
3779 = FUNCTION_VALUE (TREE_TYPE (DECL_RESULT (subr)), subr);
3782 /* Mark this reg as the function's return value. */
3783 if (GET_CODE (DECL_RTL (DECL_RESULT (subr))) == REG)
3785 REG_FUNCTION_VALUE_P (DECL_RTL (DECL_RESULT (subr))) = 1;
3786 /* Needed because we may need to move this to memory
3787 in case it's a named return value whose address is taken. */
3788 TREE_REGDECL (DECL_RESULT (subr)) = 1;
3792 /* Initialize rtx for parameters and local variables.
3793 In some cases this requires emitting insns. */
3795 assign_parms (subr, 0);
3797 /* The following was moved from init_function_start.
3798 The move is supposed to make sdb output more accurate. */
3799 /* Indicate the beginning of the function body,
3800 as opposed to parm setup. */
3801 emit_note (0, NOTE_INSN_FUNCTION_BEG);
3803 /* If doing stupid allocation, mark parms as born here. */
3805 if (GET_CODE (get_last_insn ()) != NOTE)
3806 emit_note (0, NOTE_INSN_DELETED);
3807 parm_birth_insn = get_last_insn ();
3811 for (i = LAST_VIRTUAL_REGISTER + 1; i < max_parm_reg; i++)
3812 use_variable (regno_reg_rtx[i]);
3814 if (current_function_internal_arg_pointer != virtual_incoming_args_rtx)
3815 use_variable (current_function_internal_arg_pointer);
3818 /* Fetch static chain values for containing functions. */
3819 tem = decl_function_context (current_function_decl);
3820 /* If not doing stupid register allocation, then start off with the static
3821 chain pointer in a pseudo register. Otherwise, we use the stack
3822 address that was generated above. */
3823 if (tem && ! obey_regdecls)
3824 last_ptr = copy_to_reg (static_chain_incoming_rtx);
3825 context_display = 0;
3828 tree rtlexp = make_node (RTL_EXPR);
3830 RTL_EXPR_RTL (rtlexp) = last_ptr;
3831 context_display = tree_cons (tem, rtlexp, context_display);
3832 tem = decl_function_context (tem);
3835 /* Chain thru stack frames, assuming pointer to next lexical frame
3836 is found at the place we always store it. */
3837 #ifdef FRAME_GROWS_DOWNWARD
3838 last_ptr = plus_constant (last_ptr, - GET_MODE_SIZE (Pmode));
3840 last_ptr = copy_to_reg (gen_rtx (MEM, Pmode,
3841 memory_address (Pmode, last_ptr)));
3844 /* After the display initializations is where the tail-recursion label
3845 should go, if we end up needing one. Ensure we have a NOTE here
3846 since some things (like trampolines) get placed before this. */
3847 tail_recursion_reentry = emit_note (0, NOTE_INSN_DELETED);
3849 /* Evaluate now the sizes of any types declared among the arguments. */
3850 for (tem = nreverse (get_pending_sizes ()); tem; tem = TREE_CHAIN (tem))
3851 expand_expr (TREE_VALUE (tem), 0, VOIDmode, 0);
3853 /* Make sure there is a line number after the function entry setup code. */
3854 force_next_line_note ();
3857 /* Generate RTL for the end of the current function.
3858 FILENAME and LINE are the current position in the source file. */
3860 /* It is up to language-specific callers to do cleanups for parameters. */
3863 expand_function_end (filename, line)
3870 static rtx initial_trampoline;
3872 #ifdef NON_SAVING_SETJMP
3873 /* Don't put any variables in registers if we call setjmp
3874 on a machine that fails to restore the registers. */
3875 if (NON_SAVING_SETJMP && current_function_calls_setjmp)
3877 setjmp_protect (DECL_INITIAL (current_function_decl));
3878 setjmp_protect_args ();
3882 /* Save the argument pointer if a save area was made for it. */
3883 if (arg_pointer_save_area)
3885 rtx x = gen_move_insn (arg_pointer_save_area, virtual_incoming_args_rtx);
3886 emit_insn_before (x, tail_recursion_reentry);
3889 /* Initialize any trampolines required by this function. */
3890 for (link = trampoline_list; link; link = TREE_CHAIN (link))
3892 tree function = TREE_PURPOSE (link);
3893 rtx context = lookup_static_chain (function);
3894 rtx tramp = RTL_EXPR_RTL (TREE_VALUE (link));
3897 /* First make sure this compilation has a template for
3898 initializing trampolines. */
3899 if (initial_trampoline == 0)
3901 end_temporary_allocation ();
3903 = gen_rtx (MEM, BLKmode, assemble_trampoline_template ());
3904 resume_temporary_allocation ();
3907 /* Generate insns to initialize the trampoline. */
3909 tramp = change_address (initial_trampoline, BLKmode,
3910 round_trampoline_addr (XEXP (tramp, 0)));
3911 emit_block_move (tramp, initial_trampoline,
3912 gen_rtx (CONST_INT, VOIDmode, TRAMPOLINE_SIZE),
3913 FUNCTION_BOUNDARY / BITS_PER_UNIT);
3914 INITIALIZE_TRAMPOLINE (XEXP (tramp, 0),
3915 XEXP (DECL_RTL (function), 0), context);
3919 /* Put those insns at entry to the containing function (this one). */
3920 emit_insns_before (seq, tail_recursion_reentry);
3922 /* Clear the trampoline_list for the next function. */
3923 trampoline_list = 0;
3925 #if 0 /* I think unused parms are legitimate enough. */
3926 /* Warn about unused parms. */
3931 for (decl = DECL_ARGUMENTS (current_function_decl);
3932 decl; decl = TREE_CHAIN (decl))
3933 if (! TREE_USED (decl) && TREE_CODE (decl) == VAR_DECL)
3934 warning_with_decl (decl, "unused parameter `%s'");
3938 /* Delete handlers for nonlocal gotos if nothing uses them. */
3939 if (nonlocal_goto_handler_slot != 0 && !current_function_has_nonlocal_label)
3942 /* End any sequences that failed to be closed due to syntax errors. */
3943 while (in_sequence_p ())
3946 /* Outside function body, can't compute type's actual size
3947 until next function's body starts. */
3948 immediate_size_expand--;
3950 /* If doing stupid register allocation,
3951 mark register parms as dying here. */
3956 for (i = LAST_VIRTUAL_REGISTER + 1; i < max_parm_reg; i++)
3957 use_variable (regno_reg_rtx[i]);
3959 /* Likewise for the regs of all the SAVE_EXPRs in the function. */
3961 for (tem = save_expr_regs; tem; tem = XEXP (tem, 1))
3963 use_variable (XEXP (tem, 0));
3964 use_variable_after (XEXP (tem, 0), parm_birth_insn);
3967 if (current_function_internal_arg_pointer != virtual_incoming_args_rtx)
3968 use_variable (current_function_internal_arg_pointer);
3971 clear_pending_stack_adjust ();
3972 do_pending_stack_adjust ();
3974 /* Mark the end of the function body.
3975 If control reaches this insn, the function can drop through
3976 without returning a value. */
3977 emit_note (0, NOTE_INSN_FUNCTION_END);
3979 /* Output a linenumber for the end of the function.
3980 SDB depends on this. */
3981 emit_line_note_force (filename, line);
3983 /* Output the label for the actual return from the function,
3984 if one is expected. This happens either because a function epilogue
3985 is used instead of a return instruction, or because a return was done
3986 with a goto in order to run local cleanups, or because of pcc-style
3987 structure returning. */
3990 emit_label (return_label);
3992 /* If we had calls to alloca, and this machine needs
3993 an accurate stack pointer to exit the function,
3994 insert some code to save and restore the stack pointer. */
3995 #ifdef EXIT_IGNORE_STACK
3996 if (! EXIT_IGNORE_STACK)
3998 if (current_function_calls_alloca)
4002 emit_stack_save (SAVE_FUNCTION, &tem, parm_birth_insn);
4003 emit_stack_restore (SAVE_FUNCTION, tem, 0);
4006 /* If scalar return value was computed in a pseudo-reg,
4007 copy that to the hard return register. */
4008 if (DECL_RTL (DECL_RESULT (current_function_decl)) != 0
4009 && GET_CODE (DECL_RTL (DECL_RESULT (current_function_decl))) == REG
4010 && (REGNO (DECL_RTL (DECL_RESULT (current_function_decl)))
4011 >= FIRST_PSEUDO_REGISTER))
4013 rtx real_decl_result;
4015 #ifdef FUNCTION_OUTGOING_VALUE
4017 = FUNCTION_OUTGOING_VALUE (TREE_TYPE (DECL_RESULT (current_function_decl)),
4018 current_function_decl);
4021 = FUNCTION_VALUE (TREE_TYPE (DECL_RESULT (current_function_decl)),
4022 current_function_decl);
4024 REG_FUNCTION_VALUE_P (real_decl_result) = 1;
4025 emit_move_insn (real_decl_result,
4026 DECL_RTL (DECL_RESULT (current_function_decl)));
4027 emit_insn (gen_rtx (USE, VOIDmode, real_decl_result));
4030 /* If returning a structure, arrange to return the address of the value
4031 in a place where debuggers expect to find it.
4033 If returning a structure PCC style,
4034 the caller also depends on this value.
4035 And current_function_returns_pcc_struct is not necessarily set. */
4036 if (current_function_returns_struct
4037 || current_function_returns_pcc_struct)
4039 rtx value_address = XEXP (DECL_RTL (DECL_RESULT (current_function_decl)), 0);
4040 tree type = TREE_TYPE (DECL_RESULT (current_function_decl));
4041 #ifdef FUNCTION_OUTGOING_VALUE
4043 = FUNCTION_OUTGOING_VALUE (build_pointer_type (type),
4044 current_function_decl);
4047 = FUNCTION_VALUE (build_pointer_type (type),
4048 current_function_decl);
4051 /* Mark this as a function return value so integrate will delete the
4052 assignment and USE below when inlining this function. */
4053 REG_FUNCTION_VALUE_P (outgoing) = 1;
4055 emit_move_insn (outgoing, value_address);
4056 use_variable (outgoing);
4059 /* Output a return insn if we are using one.
4060 Otherwise, let the rtl chain end here, to drop through
4061 into the epilogue. */
4066 emit_jump_insn (gen_return ());
4071 /* Fix up any gotos that jumped out to the outermost
4072 binding level of the function.
4073 Must follow emitting RETURN_LABEL. */
4075 /* If you have any cleanups to do at this point,
4076 and they need to create temporary variables,
4077 then you will lose. */
4078 fixup_gotos (0, 0, 0, get_insns (), 0);
4081 /* These arrays record the INSN_UIDs of the prologue and epilogue insns. */
4083 static int *prologue;
4084 static int *epilogue;
4086 /* Create an array that records the INSN_UIDs of INSNS (either a sequence
4087 or a single insn). */
4090 record_insns (insns)
4095 if (GET_CODE (insns) == SEQUENCE)
4097 int len = XVECLEN (insns, 0);
4098 vec = (int *) oballoc ((len + 1) * sizeof (int));
4101 vec[len] = INSN_UID (XVECEXP (insns, 0, len));
4105 vec = (int *) oballoc (2 * sizeof (int));
4106 vec[0] = INSN_UID (insns);
4112 /* Determine whether INSN is in the array of INSN_UIDs VEC. */
4115 contains (insn, vec)
4121 if (GET_CODE (insn) == INSN
4122 && GET_CODE (PATTERN (insn)) == SEQUENCE)
4124 for (i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
4125 for (j = 0; vec[j]; j++)
4126 if (INSN_UID (XVECEXP (PATTERN (insn), 0, i)) == vec[j])
4127 return XVECEXP (PATTERN (insn), 0, i);
4131 for (j = 0; vec[j]; j++)
4132 if (INSN_UID (insn) == vec[j])
4138 /* Generate the prologe and epilogue RTL if the machine supports it. Thread
4139 this into place with notes indicating where the prologue ends and where
4140 the epilogue begins. Update the basic block information when possible. */
4143 thread_prologue_and_epilogue_insns (f)
4146 #ifdef HAVE_prologue
4149 rtx head, seq, insn;
4151 /* The first insn (a NOTE_INSN_DELETED) is followed by zero or more
4152 prologue insns and a NOTE_INSN_PROLOGUE_END. */
4153 emit_note_after (NOTE_INSN_PROLOGUE_END, f);
4154 seq = gen_prologue ();
4155 head = emit_insn_after (seq, f);
4157 /* Include the new prologue insns in the first block. Ignore them
4158 if they form a basic block unto themselves. */
4159 if (basic_block_head && n_basic_blocks
4160 && GET_CODE (basic_block_head[0]) != CODE_LABEL)
4161 basic_block_head[0] = NEXT_INSN (f);
4163 /* Retain a map of the prologue insns. */
4164 prologue = record_insns (GET_CODE (seq) == SEQUENCE ? seq : head);
4170 #ifdef HAVE_epilogue
4173 rtx insn = get_last_insn ();
4174 rtx prev = prev_nonnote_insn (insn);
4176 /* If we end with a BARRIER, we don't need an epilogue. */
4177 if (! (prev && GET_CODE (prev) == BARRIER))
4181 /* The last basic block ends with a NOTE_INSN_EPILOGUE_BEG,
4182 the epilogue insns (this must include the jump insn that
4183 returns), USE insns ad the end of a function, and a BARRIER. */
4185 emit_barrier_after (insn);
4187 /* Place the epilogue before the USE insns at the end of a
4190 && GET_CODE (prev) == INSN
4191 && GET_CODE (PATTERN (prev)) == USE)
4193 insn = PREV_INSN (prev);
4194 prev = prev_nonnote_insn (prev);
4197 seq = gen_epilogue ();
4198 tail = emit_jump_insn_after (seq, insn);
4199 emit_note_after (NOTE_INSN_EPILOGUE_BEG, insn);
4201 /* Include the new epilogue insns in the last block. Ignore
4202 them if they form a basic block unto themselves. */
4203 if (basic_block_end && n_basic_blocks
4204 && GET_CODE (basic_block_end[n_basic_blocks - 1]) != JUMP_INSN)
4205 basic_block_end[n_basic_blocks - 1] = tail;
4207 /* Retain a map of the epilogue insns. */
4208 epilogue = record_insns (GET_CODE (seq) == SEQUENCE ? seq : tail);
4216 /* Reposition the prologue-end and epilogue-begin notes after instruction
4217 scheduling and delayed branch scheduling. */
4220 reposition_prologue_and_epilogue_notes (f)
4223 #if defined (HAVE_prologue) || defined (HAVE_epilogue)
4224 /* Reposition the prologue and epilogue notes. */
4231 register rtx insn, end_prologue;
4233 /* From the end of the first basic block, search backward for a
4235 for (insn = NEXT_INSN (PREV_INSN (basic_block_end[0]));
4236 insn; insn = prev_nonnote_insn (insn))
4237 if (contains (insn, prologue))
4239 end_prologue = insn;
4240 /* Find the prologue-end note and move it to just after the
4241 last prologue insn. */
4242 for (insn = f; insn; insn = NEXT_INSN (insn))
4243 if (GET_CODE (insn) == NOTE
4244 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_PROLOGUE_END)
4246 next = NEXT_INSN (insn);
4247 prev = PREV_INSN (insn);
4249 NEXT_INSN (prev) = next;
4251 PREV_INSN (next) = prev;
4252 add_insn_after (insn, end_prologue);
4259 register rtx insn, beg_epilogue;
4261 /* From the start of the last basic block, search forward for an
4263 for (insn = PREV_INSN (NEXT_INSN (basic_block_head[n_basic_blocks - 1]));
4264 insn; insn = next_nonnote_insn (insn))
4265 if (beg_epilogue = contains (insn, epilogue))
4267 /* Find the epilogue-begin note and move it to just before
4268 the first epilogue insn. */
4269 for (insn = get_last_insn (); insn; insn = PREV_INSN (insn))
4270 if (GET_CODE (insn) == NOTE
4271 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_EPILOGUE_BEG)
4273 next = NEXT_INSN (insn);
4274 prev = PREV_INSN (insn);
4276 NEXT_INSN (prev) = next;
4278 PREV_INSN (next) = prev;
4279 add_insn_after (insn, PREV_INSN (beg_epilogue));
4284 #endif /* HAVE_prologue or HAVE_epilogue */