1 /* Variable tracking routines for the GNU compiler.
2 Copyright (C) 2002, 2003, 2004, 2005 Free Software Foundation, Inc.
4 This file is part of GCC.
6 GCC is free software; you can redistribute it and/or modify it
7 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 GCC is distributed in the hope that it will be useful, but WITHOUT
12 ANY WARRANTY; without even the implied warranty of MERCHANTABILITY
13 or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public
14 License for more details.
16 You should have received a copy of the GNU General Public License
17 along with GCC; see the file COPYING. If not, write to the Free
18 Software Foundation, 59 Temple Place - Suite 330, Boston, MA
21 /* This file contains the variable tracking pass. It computes where
22 variables are located (which registers or where in memory) at each position
23 in instruction stream and emits notes describing the locations.
24 Debug information (DWARF2 location lists) is finally generated from
26 With this debug information, it is possible to show variables
27 even when debugging optimized code.
29 How does the variable tracking pass work?
31 First, it scans RTL code for uses, stores and clobbers (register/memory
32 references in instructions), for call insns and for stack adjustments
33 separately for each basic block and saves them to an array of micro
35 The micro operations of one instruction are ordered so that
36 pre-modifying stack adjustment < use < use with no var < call insn <
37 < set < clobber < post-modifying stack adjustment
39 Then, a forward dataflow analysis is performed to find out how locations
40 of variables change through code and to propagate the variable locations
41 along control flow graph.
42 The IN set for basic block BB is computed as a union of OUT sets of BB's
43 predecessors, the OUT set for BB is copied from the IN set for BB and
44 is changed according to micro operations in BB.
46 The IN and OUT sets for basic blocks consist of a current stack adjustment
47 (used for adjusting offset of variables addressed using stack pointer),
48 the table of structures describing the locations of parts of a variable
49 and for each physical register a linked list for each physical register.
50 The linked list is a list of variable parts stored in the register,
51 i.e. it is a list of triplets (reg, decl, offset) where decl is
52 REG_EXPR (reg) and offset is REG_OFFSET (reg). The linked list is used for
53 effective deleting appropriate variable parts when we set or clobber the
56 There may be more than one variable part in a register. The linked lists
57 should be pretty short so it is a good data structure here.
58 For example in the following code, register allocator may assign same
59 register to variables A and B, and both of them are stored in the same
72 Finally, the NOTE_INSN_VAR_LOCATION notes describing the variable locations
73 are emitted to appropriate positions in RTL code. Each such a note describes
74 the location of one variable at the point in instruction stream where the
75 note is. There is no need to emit a note for each variable before each
76 instruction, we only emit these notes where the location of variable changes
77 (this means that we also emit notes for changes between the OUT set of the
78 previous block and the IN set of the current block).
80 The notes consist of two parts:
81 1. the declaration (from REG_EXPR or MEM_EXPR)
82 2. the location of a variable - it is either a simple register/memory
83 reference (for simple variables, for example int),
84 or a parallel of register/memory references (for a large variables
85 which consist of several parts, for example long long).
91 #include "coretypes.h"
95 #include "hard-reg-set.h"
96 #include "basic-block.h"
99 #include "insn-config.h"
102 #include "alloc-pool.h"
106 /* Type of micro operation. */
107 enum micro_operation_type
109 MO_USE, /* Use location (REG or MEM). */
110 MO_USE_NO_VAR,/* Use location which is not associated with a variable
111 or the variable is not trackable. */
112 MO_SET, /* Set location. */
113 MO_CLOBBER, /* Clobber location. */
114 MO_CALL, /* Call insn. */
115 MO_ADJUST /* Adjust stack pointer. */
118 /* Where shall the note be emitted? BEFORE or AFTER the instruction. */
121 EMIT_NOTE_BEFORE_INSN,
125 /* Structure holding information about micro operation. */
126 typedef struct micro_operation_def
128 /* Type of micro operation. */
129 enum micro_operation_type type;
135 /* Stack adjustment. */
136 HOST_WIDE_INT adjust;
139 /* The instruction which the micro operation is in. */
143 /* Structure for passing some other parameters to function
144 emit_note_insn_var_location. */
145 typedef struct emit_note_data_def
147 /* The instruction which the note will be emitted before/after. */
150 /* Where the note will be emitted (before/after insn)? */
151 enum emit_note_where where;
154 /* Description of location of a part of a variable. The content of a physical
155 register is described by a chain of these structures.
156 The chains are pretty short (usually 1 or 2 elements) and thus
157 chain is the best data structure. */
158 typedef struct attrs_def
160 /* Pointer to next member of the list. */
161 struct attrs_def *next;
163 /* The rtx of register. */
166 /* The declaration corresponding to LOC. */
169 /* Offset from start of DECL. */
170 HOST_WIDE_INT offset;
173 /* Structure holding the IN or OUT set for a basic block. */
174 typedef struct dataflow_set_def
176 /* Adjustment of stack offset. */
177 HOST_WIDE_INT stack_adjust;
179 /* Attributes for registers (lists of attrs). */
180 attrs regs[FIRST_PSEUDO_REGISTER];
182 /* Variable locations. */
186 /* The structure (one for each basic block) containing the information
187 needed for variable tracking. */
188 typedef struct variable_tracking_info_def
190 /* Number of micro operations stored in the MOS array. */
193 /* The array of micro operations. */
194 micro_operation *mos;
196 /* The IN and OUT set for dataflow analysis. */
200 /* Has the block been visited in DFS? */
202 } *variable_tracking_info;
204 /* Structure for chaining the locations. */
205 typedef struct location_chain_def
207 /* Next element in the chain. */
208 struct location_chain_def *next;
210 /* The location (REG or MEM). */
214 /* Structure describing one part of variable. */
215 typedef struct variable_part_def
217 /* Chain of locations of the part. */
218 location_chain loc_chain;
220 /* Location which was last emitted to location list. */
223 /* The offset in the variable. */
224 HOST_WIDE_INT offset;
227 /* Maximum number of location parts. */
228 #define MAX_VAR_PARTS 16
230 /* Structure describing where the variable is located. */
231 typedef struct variable_def
233 /* The declaration of the variable. */
236 /* Reference count. */
239 /* Number of variable parts. */
242 /* The variable parts. */
243 variable_part var_part[MAX_VAR_PARTS];
246 /* Hash function for DECL for VARIABLE_HTAB. */
247 #define VARIABLE_HASH_VAL(decl) (DECL_UID (decl))
249 /* Pointer to the BB's information specific to variable tracking pass. */
250 #define VTI(BB) ((variable_tracking_info) (BB)->aux)
252 /* Alloc pool for struct attrs_def. */
253 static alloc_pool attrs_pool;
255 /* Alloc pool for struct variable_def. */
256 static alloc_pool var_pool;
258 /* Alloc pool for struct location_chain_def. */
259 static alloc_pool loc_chain_pool;
261 /* Changed variables, notes will be emitted for them. */
262 static htab_t changed_variables;
264 /* Shall notes be emitted? */
265 static bool emit_notes;
267 /* Fake variable for stack pointer. */
268 tree frame_base_decl;
270 /* Stack adjust caused by function prologue. */
271 static HOST_WIDE_INT frame_stack_adjust;
273 /* Local function prototypes. */
274 static void stack_adjust_offset_pre_post (rtx, HOST_WIDE_INT *,
276 static void insn_stack_adjust_offset_pre_post (rtx, HOST_WIDE_INT *,
278 static void bb_stack_adjust_offset (basic_block);
279 static HOST_WIDE_INT prologue_stack_adjust (void);
280 static bool vt_stack_adjustments (void);
281 static rtx adjust_stack_reference (rtx, HOST_WIDE_INT);
282 static hashval_t variable_htab_hash (const void *);
283 static int variable_htab_eq (const void *, const void *);
284 static void variable_htab_free (void *);
286 static void init_attrs_list_set (attrs *);
287 static void attrs_list_clear (attrs *);
288 static attrs attrs_list_member (attrs, tree, HOST_WIDE_INT);
289 static void attrs_list_insert (attrs *, tree, HOST_WIDE_INT, rtx);
290 static void attrs_list_copy (attrs *, attrs);
291 static void attrs_list_union (attrs *, attrs);
293 static void vars_clear (htab_t);
294 static variable unshare_variable (dataflow_set *set, variable var);
295 static int vars_copy_1 (void **, void *);
296 static void vars_copy (htab_t, htab_t);
297 static void var_reg_delete_and_set (dataflow_set *, rtx);
298 static void var_reg_delete (dataflow_set *, rtx);
299 static void var_regno_delete (dataflow_set *, int);
300 static void var_mem_delete_and_set (dataflow_set *, rtx);
301 static void var_mem_delete (dataflow_set *, rtx);
303 static void dataflow_set_init (dataflow_set *, int);
304 static void dataflow_set_clear (dataflow_set *);
305 static void dataflow_set_copy (dataflow_set *, dataflow_set *);
306 static int variable_union_info_cmp_pos (const void *, const void *);
307 static int variable_union (void **, void *);
308 static void dataflow_set_union (dataflow_set *, dataflow_set *);
309 static bool variable_part_different_p (variable_part *, variable_part *);
310 static bool variable_different_p (variable, variable, bool);
311 static int dataflow_set_different_1 (void **, void *);
312 static int dataflow_set_different_2 (void **, void *);
313 static bool dataflow_set_different (dataflow_set *, dataflow_set *);
314 static void dataflow_set_destroy (dataflow_set *);
316 static bool contains_symbol_ref (rtx);
317 static bool track_expr_p (tree);
318 static int count_uses (rtx *, void *);
319 static void count_uses_1 (rtx *, void *);
320 static void count_stores (rtx, rtx, void *);
321 static int add_uses (rtx *, void *);
322 static void add_uses_1 (rtx *, void *);
323 static void add_stores (rtx, rtx, void *);
324 static bool compute_bb_dataflow (basic_block);
325 static void vt_find_locations (void);
327 static void dump_attrs_list (attrs);
328 static int dump_variable (void **, void *);
329 static void dump_vars (htab_t);
330 static void dump_dataflow_set (dataflow_set *);
331 static void dump_dataflow_sets (void);
333 static void variable_was_changed (variable, htab_t);
334 static void set_frame_base_location (dataflow_set *, rtx);
335 static void set_variable_part (dataflow_set *, rtx, tree, HOST_WIDE_INT);
336 static void delete_variable_part (dataflow_set *, rtx, tree, HOST_WIDE_INT);
337 static int emit_note_insn_var_location (void **, void *);
338 static void emit_notes_for_changes (rtx, enum emit_note_where);
339 static int emit_notes_for_differences_1 (void **, void *);
340 static int emit_notes_for_differences_2 (void **, void *);
341 static void emit_notes_for_differences (rtx, dataflow_set *, dataflow_set *);
342 static void emit_notes_in_bb (basic_block);
343 static void vt_emit_notes (void);
345 static bool vt_get_decl_and_offset (rtx, tree *, HOST_WIDE_INT *);
346 static void vt_add_function_parameters (void);
347 static void vt_initialize (void);
348 static void vt_finalize (void);
350 /* Given a SET, calculate the amount of stack adjustment it contains
351 PRE- and POST-modifying stack pointer.
352 This function is similar to stack_adjust_offset. */
355 stack_adjust_offset_pre_post (rtx pattern, HOST_WIDE_INT *pre,
358 rtx src = SET_SRC (pattern);
359 rtx dest = SET_DEST (pattern);
362 if (dest == stack_pointer_rtx)
364 /* (set (reg sp) (plus (reg sp) (const_int))) */
365 code = GET_CODE (src);
366 if (! (code == PLUS || code == MINUS)
367 || XEXP (src, 0) != stack_pointer_rtx
368 || GET_CODE (XEXP (src, 1)) != CONST_INT)
372 *post += INTVAL (XEXP (src, 1));
374 *post -= INTVAL (XEXP (src, 1));
376 else if (MEM_P (dest))
378 /* (set (mem (pre_dec (reg sp))) (foo)) */
379 src = XEXP (dest, 0);
380 code = GET_CODE (src);
386 if (XEXP (src, 0) == stack_pointer_rtx)
388 rtx val = XEXP (XEXP (src, 1), 1);
389 /* We handle only adjustments by constant amount. */
390 gcc_assert (GET_CODE (XEXP (src, 1)) == PLUS &&
391 GET_CODE (val) == CONST_INT);
393 if (code == PRE_MODIFY)
394 *pre -= INTVAL (val);
396 *post -= INTVAL (val);
402 if (XEXP (src, 0) == stack_pointer_rtx)
404 *pre += GET_MODE_SIZE (GET_MODE (dest));
410 if (XEXP (src, 0) == stack_pointer_rtx)
412 *post += GET_MODE_SIZE (GET_MODE (dest));
418 if (XEXP (src, 0) == stack_pointer_rtx)
420 *pre -= GET_MODE_SIZE (GET_MODE (dest));
426 if (XEXP (src, 0) == stack_pointer_rtx)
428 *post -= GET_MODE_SIZE (GET_MODE (dest));
439 /* Given an INSN, calculate the amount of stack adjustment it contains
440 PRE- and POST-modifying stack pointer. */
443 insn_stack_adjust_offset_pre_post (rtx insn, HOST_WIDE_INT *pre,
449 if (GET_CODE (PATTERN (insn)) == SET)
450 stack_adjust_offset_pre_post (PATTERN (insn), pre, post);
451 else if (GET_CODE (PATTERN (insn)) == PARALLEL
452 || GET_CODE (PATTERN (insn)) == SEQUENCE)
456 /* There may be stack adjustments inside compound insns. Search
458 for ( i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
459 if (GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == SET)
460 stack_adjust_offset_pre_post (XVECEXP (PATTERN (insn), 0, i),
465 /* Compute stack adjustment in basic block BB. */
468 bb_stack_adjust_offset (basic_block bb)
470 HOST_WIDE_INT offset;
473 offset = VTI (bb)->in.stack_adjust;
474 for (i = 0; i < VTI (bb)->n_mos; i++)
476 if (VTI (bb)->mos[i].type == MO_ADJUST)
477 offset += VTI (bb)->mos[i].u.adjust;
478 else if (VTI (bb)->mos[i].type != MO_CALL)
480 if (MEM_P (VTI (bb)->mos[i].u.loc))
482 VTI (bb)->mos[i].u.loc
483 = adjust_stack_reference (VTI (bb)->mos[i].u.loc, -offset);
487 VTI (bb)->out.stack_adjust = offset;
490 /* Compute stack adjustment caused by function prologue. */
493 prologue_stack_adjust (void)
495 HOST_WIDE_INT offset = 0;
496 basic_block bb = ENTRY_BLOCK_PTR->next_bb;
503 end = NEXT_INSN (BB_END (bb));
504 for (insn = BB_HEAD (bb); insn != end; insn = NEXT_INSN (insn))
507 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_PROLOGUE_END)
514 insn_stack_adjust_offset_pre_post (insn, &tmp, &tmp);
522 /* Compute stack adjustments for all blocks by traversing DFS tree.
523 Return true when the adjustments on all incoming edges are consistent.
524 Heavily borrowed from flow_depth_first_order_compute. */
527 vt_stack_adjustments (void)
529 edge_iterator *stack;
532 /* Initialize entry block. */
533 VTI (ENTRY_BLOCK_PTR)->visited = true;
534 VTI (ENTRY_BLOCK_PTR)->out.stack_adjust = frame_stack_adjust;
536 /* Allocate stack for back-tracking up CFG. */
537 stack = xmalloc ((n_basic_blocks + 1) * sizeof (edge_iterator));
540 /* Push the first edge on to the stack. */
541 stack[sp++] = ei_start (ENTRY_BLOCK_PTR->succs);
549 /* Look at the edge on the top of the stack. */
551 src = ei_edge (ei)->src;
552 dest = ei_edge (ei)->dest;
554 /* Check if the edge destination has been visited yet. */
555 if (!VTI (dest)->visited)
557 VTI (dest)->visited = true;
558 VTI (dest)->in.stack_adjust = VTI (src)->out.stack_adjust;
559 bb_stack_adjust_offset (dest);
561 if (EDGE_COUNT (dest->succs) > 0)
562 /* Since the DEST node has been visited for the first
563 time, check its successors. */
564 stack[sp++] = ei_start (dest->succs);
568 /* Check whether the adjustments on the edges are the same. */
569 if (VTI (dest)->in.stack_adjust != VTI (src)->out.stack_adjust)
575 if (! ei_one_before_end_p (ei))
576 /* Go to the next edge. */
577 ei_next (&stack[sp - 1]);
579 /* Return to previous level if there are no more edges. */
588 /* Adjust stack reference MEM by ADJUSTMENT bytes and return the new rtx. */
591 adjust_stack_reference (rtx mem, HOST_WIDE_INT adjustment)
599 adjusted_mem = copy_rtx (mem);
600 XEXP (adjusted_mem, 0) = replace_rtx (XEXP (adjusted_mem, 0),
602 gen_rtx_PLUS (Pmode, stack_pointer_rtx,
603 GEN_INT (adjustment)));
604 tmp = simplify_rtx (XEXP (adjusted_mem, 0));
606 XEXP (adjusted_mem, 0) = tmp;
611 /* The hash function for variable_htab, computes the hash value
612 from the declaration of variable X. */
615 variable_htab_hash (const void *x)
617 const variable v = (const variable) x;
619 return (VARIABLE_HASH_VAL (v->decl));
622 /* Compare the declaration of variable X with declaration Y. */
625 variable_htab_eq (const void *x, const void *y)
627 const variable v = (const variable) x;
628 const tree decl = (const tree) y;
630 return (VARIABLE_HASH_VAL (v->decl) == VARIABLE_HASH_VAL (decl));
633 /* Free the element of VARIABLE_HTAB (its type is struct variable_def). */
636 variable_htab_free (void *elem)
639 variable var = (variable) elem;
640 location_chain node, next;
642 gcc_assert (var->refcount > 0);
645 if (var->refcount > 0)
648 for (i = 0; i < var->n_var_parts; i++)
650 for (node = var->var_part[i].loc_chain; node; node = next)
653 pool_free (loc_chain_pool, node);
655 var->var_part[i].loc_chain = NULL;
657 pool_free (var_pool, var);
660 /* Initialize the set (array) SET of attrs to empty lists. */
663 init_attrs_list_set (attrs *set)
667 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
671 /* Make the list *LISTP empty. */
674 attrs_list_clear (attrs *listp)
678 for (list = *listp; list; list = next)
681 pool_free (attrs_pool, list);
686 /* Return true if the pair of DECL and OFFSET is the member of the LIST. */
689 attrs_list_member (attrs list, tree decl, HOST_WIDE_INT offset)
691 for (; list; list = list->next)
692 if (list->decl == decl && list->offset == offset)
697 /* Insert the triplet DECL, OFFSET, LOC to the list *LISTP. */
700 attrs_list_insert (attrs *listp, tree decl, HOST_WIDE_INT offset, rtx loc)
704 list = pool_alloc (attrs_pool);
707 list->offset = offset;
712 /* Copy all nodes from SRC and create a list *DSTP of the copies. */
715 attrs_list_copy (attrs *dstp, attrs src)
719 attrs_list_clear (dstp);
720 for (; src; src = src->next)
722 n = pool_alloc (attrs_pool);
725 n->offset = src->offset;
731 /* Add all nodes from SRC which are not in *DSTP to *DSTP. */
734 attrs_list_union (attrs *dstp, attrs src)
736 for (; src; src = src->next)
738 if (!attrs_list_member (*dstp, src->decl, src->offset))
739 attrs_list_insert (dstp, src->decl, src->offset, src->loc);
743 /* Delete all variables from hash table VARS. */
746 vars_clear (htab_t vars)
751 /* Return a copy of a variable VAR and insert it to dataflow set SET. */
754 unshare_variable (dataflow_set *set, variable var)
760 new_var = pool_alloc (var_pool);
761 new_var->decl = var->decl;
762 new_var->refcount = 1;
764 new_var->n_var_parts = var->n_var_parts;
766 for (i = 0; i < var->n_var_parts; i++)
769 location_chain *nextp;
771 new_var->var_part[i].offset = var->var_part[i].offset;
772 nextp = &new_var->var_part[i].loc_chain;
773 for (node = var->var_part[i].loc_chain; node; node = node->next)
775 location_chain new_lc;
777 new_lc = pool_alloc (loc_chain_pool);
779 new_lc->loc = node->loc;
782 nextp = &new_lc->next;
785 /* We are at the basic block boundary when copying variable description
786 so set the CUR_LOC to be the first element of the chain. */
787 if (new_var->var_part[i].loc_chain)
788 new_var->var_part[i].cur_loc = new_var->var_part[i].loc_chain->loc;
790 new_var->var_part[i].cur_loc = NULL;
793 slot = htab_find_slot_with_hash (set->vars, new_var->decl,
794 VARIABLE_HASH_VAL (new_var->decl),
800 /* Add a variable from *SLOT to hash table DATA and increase its reference
804 vars_copy_1 (void **slot, void *data)
806 htab_t dst = (htab_t) data;
809 src = *(variable *) slot;
812 dstp = (variable *) htab_find_slot_with_hash (dst, src->decl,
813 VARIABLE_HASH_VAL (src->decl),
817 /* Continue traversing the hash table. */
821 /* Copy all variables from hash table SRC to hash table DST. */
824 vars_copy (htab_t dst, htab_t src)
827 htab_traverse (src, vars_copy_1, dst);
830 /* Delete current content of register LOC in dataflow set SET
831 and set the register to contain REG_EXPR (LOC), REG_OFFSET (LOC). */
834 var_reg_delete_and_set (dataflow_set *set, rtx loc)
836 tree decl = REG_EXPR (loc);
837 HOST_WIDE_INT offset = REG_OFFSET (loc);
841 nextp = &set->regs[REGNO (loc)];
842 for (node = *nextp; node; node = next)
845 if (node->decl != decl || node->offset != offset)
847 delete_variable_part (set, node->loc, node->decl, node->offset);
848 pool_free (attrs_pool, node);
857 if (set->regs[REGNO (loc)] == NULL)
858 attrs_list_insert (&set->regs[REGNO (loc)], decl, offset, loc);
859 set_variable_part (set, loc, decl, offset);
862 /* Delete current content of register LOC in dataflow set SET. */
865 var_reg_delete (dataflow_set *set, rtx loc)
867 attrs *reg = &set->regs[REGNO (loc)];
870 for (node = *reg; node; node = next)
873 delete_variable_part (set, node->loc, node->decl, node->offset);
874 pool_free (attrs_pool, node);
879 /* Delete content of register with number REGNO in dataflow set SET. */
882 var_regno_delete (dataflow_set *set, int regno)
884 attrs *reg = &set->regs[regno];
887 for (node = *reg; node; node = next)
890 delete_variable_part (set, node->loc, node->decl, node->offset);
891 pool_free (attrs_pool, node);
896 /* Delete and set the location part of variable MEM_EXPR (LOC)
897 in dataflow set SET to LOC.
898 Adjust the address first if it is stack pointer based. */
901 var_mem_delete_and_set (dataflow_set *set, rtx loc)
903 tree decl = MEM_EXPR (loc);
904 HOST_WIDE_INT offset = MEM_OFFSET (loc) ? INTVAL (MEM_OFFSET (loc)) : 0;
906 set_variable_part (set, loc, decl, offset);
909 /* Delete the location part LOC from dataflow set SET.
910 Adjust the address first if it is stack pointer based. */
913 var_mem_delete (dataflow_set *set, rtx loc)
915 tree decl = MEM_EXPR (loc);
916 HOST_WIDE_INT offset = MEM_OFFSET (loc) ? INTVAL (MEM_OFFSET (loc)) : 0;
918 delete_variable_part (set, loc, decl, offset);
921 /* Initialize dataflow set SET to be empty.
922 VARS_SIZE is the initial size of hash table VARS. */
925 dataflow_set_init (dataflow_set *set, int vars_size)
927 init_attrs_list_set (set->regs);
928 set->vars = htab_create (vars_size, variable_htab_hash, variable_htab_eq,
930 set->stack_adjust = 0;
933 /* Delete the contents of dataflow set SET. */
936 dataflow_set_clear (dataflow_set *set)
940 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
941 attrs_list_clear (&set->regs[i]);
943 vars_clear (set->vars);
946 /* Copy the contents of dataflow set SRC to DST. */
949 dataflow_set_copy (dataflow_set *dst, dataflow_set *src)
953 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
954 attrs_list_copy (&dst->regs[i], src->regs[i]);
956 vars_copy (dst->vars, src->vars);
957 dst->stack_adjust = src->stack_adjust;
960 /* Information for merging lists of locations for a given offset of variable.
962 struct variable_union_info
964 /* Node of the location chain. */
967 /* The sum of positions in the input chains. */
970 /* The position in the chains of SRC and DST dataflow sets. */
975 /* Compare function for qsort, order the structures by POS element. */
978 variable_union_info_cmp_pos (const void *n1, const void *n2)
980 const struct variable_union_info *i1 = n1;
981 const struct variable_union_info *i2 = n2;
983 if (i1->pos != i2->pos)
984 return i1->pos - i2->pos;
986 return (i1->pos_dst - i2->pos_dst);
989 /* Compute union of location parts of variable *SLOT and the same variable
990 from hash table DATA. Compute "sorted" union of the location chains
991 for common offsets, i.e. the locations of a variable part are sorted by
992 a priority where the priority is the sum of the positions in the 2 chains
993 (if a location is only in one list the position in the second list is
994 defined to be larger than the length of the chains).
995 When we are updating the location parts the newest location is in the
996 beginning of the chain, so when we do the described "sorted" union
997 we keep the newest locations in the beginning. */
1000 variable_union (void **slot, void *data)
1002 variable src, dst, *dstp;
1003 dataflow_set *set = (dataflow_set *) data;
1006 src = *(variable *) slot;
1007 dstp = (variable *) htab_find_slot_with_hash (set->vars, src->decl,
1008 VARIABLE_HASH_VAL (src->decl),
1014 /* If CUR_LOC of some variable part is not the first element of
1015 the location chain we are going to change it so we have to make
1016 a copy of the variable. */
1017 for (k = 0; k < src->n_var_parts; k++)
1019 gcc_assert (!src->var_part[k].loc_chain
1020 == !src->var_part[k].cur_loc);
1021 if (src->var_part[k].loc_chain)
1023 gcc_assert (src->var_part[k].cur_loc);
1024 if (src->var_part[k].cur_loc != src->var_part[k].loc_chain->loc)
1028 if (k < src->n_var_parts)
1029 unshare_variable (set, src);
1033 /* Continue traversing the hash table. */
1039 gcc_assert (src->n_var_parts);
1041 /* Count the number of location parts, result is K. */
1042 for (i = 0, j = 0, k = 0;
1043 i < src->n_var_parts && j < dst->n_var_parts; k++)
1045 if (src->var_part[i].offset == dst->var_part[j].offset)
1050 else if (src->var_part[i].offset < dst->var_part[j].offset)
1055 k += src->n_var_parts - i;
1056 k += dst->n_var_parts - j;
1058 /* We track only variables whose size is <= MAX_VAR_PARTS bytes
1059 thus there are at most MAX_VAR_PARTS different offsets. */
1060 gcc_assert (k <= MAX_VAR_PARTS);
1062 if (dst->refcount > 1 && dst->n_var_parts != k)
1063 dst = unshare_variable (set, dst);
1065 i = src->n_var_parts - 1;
1066 j = dst->n_var_parts - 1;
1067 dst->n_var_parts = k;
1069 for (k--; k >= 0; k--)
1071 location_chain node, node2;
1073 if (i >= 0 && j >= 0
1074 && src->var_part[i].offset == dst->var_part[j].offset)
1076 /* Compute the "sorted" union of the chains, i.e. the locations which
1077 are in both chains go first, they are sorted by the sum of
1078 positions in the chains. */
1081 struct variable_union_info *vui;
1083 /* If DST is shared compare the location chains.
1084 If they are different we will modify the chain in DST with
1085 high probability so make a copy of DST. */
1086 if (dst->refcount > 1)
1088 for (node = src->var_part[i].loc_chain,
1089 node2 = dst->var_part[j].loc_chain; node && node2;
1090 node = node->next, node2 = node2->next)
1092 if (!((REG_P (node2->loc)
1093 && REG_P (node->loc)
1094 && REGNO (node2->loc) == REGNO (node->loc))
1095 || rtx_equal_p (node2->loc, node->loc)))
1099 dst = unshare_variable (set, dst);
1103 for (node = src->var_part[i].loc_chain; node; node = node->next)
1106 for (node = dst->var_part[j].loc_chain; node; node = node->next)
1108 vui = xcalloc (src_l + dst_l, sizeof (struct variable_union_info));
1110 /* Fill in the locations from DST. */
1111 for (node = dst->var_part[j].loc_chain, jj = 0; node;
1112 node = node->next, jj++)
1115 vui[jj].pos_dst = jj;
1117 /* Value larger than a sum of 2 valid positions. */
1118 vui[jj].pos_src = src_l + dst_l;
1121 /* Fill in the locations from SRC. */
1123 for (node = src->var_part[i].loc_chain, ii = 0; node;
1124 node = node->next, ii++)
1126 /* Find location from NODE. */
1127 for (jj = 0; jj < dst_l; jj++)
1129 if ((REG_P (vui[jj].lc->loc)
1130 && REG_P (node->loc)
1131 && REGNO (vui[jj].lc->loc) == REGNO (node->loc))
1132 || rtx_equal_p (vui[jj].lc->loc, node->loc))
1134 vui[jj].pos_src = ii;
1138 if (jj >= dst_l) /* The location has not been found. */
1140 location_chain new_node;
1142 /* Copy the location from SRC. */
1143 new_node = pool_alloc (loc_chain_pool);
1144 new_node->loc = node->loc;
1145 vui[n].lc = new_node;
1146 vui[n].pos_src = ii;
1147 vui[n].pos_dst = src_l + dst_l;
1152 for (ii = 0; ii < src_l + dst_l; ii++)
1153 vui[ii].pos = vui[ii].pos_src + vui[ii].pos_dst;
1155 qsort (vui, n, sizeof (struct variable_union_info),
1156 variable_union_info_cmp_pos);
1158 /* Reconnect the nodes in sorted order. */
1159 for (ii = 1; ii < n; ii++)
1160 vui[ii - 1].lc->next = vui[ii].lc;
1161 vui[n - 1].lc->next = NULL;
1163 dst->var_part[k].loc_chain = vui[0].lc;
1164 dst->var_part[k].offset = dst->var_part[j].offset;
1170 else if ((i >= 0 && j >= 0
1171 && src->var_part[i].offset < dst->var_part[j].offset)
1174 dst->var_part[k] = dst->var_part[j];
1177 else if ((i >= 0 && j >= 0
1178 && src->var_part[i].offset > dst->var_part[j].offset)
1181 location_chain *nextp;
1183 /* Copy the chain from SRC. */
1184 nextp = &dst->var_part[k].loc_chain;
1185 for (node = src->var_part[i].loc_chain; node; node = node->next)
1187 location_chain new_lc;
1189 new_lc = pool_alloc (loc_chain_pool);
1190 new_lc->next = NULL;
1191 new_lc->loc = node->loc;
1194 nextp = &new_lc->next;
1197 dst->var_part[k].offset = src->var_part[i].offset;
1201 /* We are at the basic block boundary when computing union
1202 so set the CUR_LOC to be the first element of the chain. */
1203 if (dst->var_part[k].loc_chain)
1204 dst->var_part[k].cur_loc = dst->var_part[k].loc_chain->loc;
1206 dst->var_part[k].cur_loc = NULL;
1209 /* Continue traversing the hash table. */
1213 /* Compute union of dataflow sets SRC and DST and store it to DST. */
1216 dataflow_set_union (dataflow_set *dst, dataflow_set *src)
1220 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1221 attrs_list_union (&dst->regs[i], src->regs[i]);
1223 htab_traverse (src->vars, variable_union, dst);
1226 /* Flag whether two dataflow sets being compared contain different data. */
1228 dataflow_set_different_value;
1231 variable_part_different_p (variable_part *vp1, variable_part *vp2)
1233 location_chain lc1, lc2;
1235 for (lc1 = vp1->loc_chain; lc1; lc1 = lc1->next)
1237 for (lc2 = vp2->loc_chain; lc2; lc2 = lc2->next)
1239 if (REG_P (lc1->loc) && REG_P (lc2->loc))
1241 if (REGNO (lc1->loc) == REGNO (lc2->loc))
1244 if (rtx_equal_p (lc1->loc, lc2->loc))
1253 /* Return true if variables VAR1 and VAR2 are different.
1254 If COMPARE_CURRENT_LOCATION is true compare also the cur_loc of each
1258 variable_different_p (variable var1, variable var2,
1259 bool compare_current_location)
1266 if (var1->n_var_parts != var2->n_var_parts)
1269 for (i = 0; i < var1->n_var_parts; i++)
1271 if (var1->var_part[i].offset != var2->var_part[i].offset)
1273 if (compare_current_location)
1275 if (!((REG_P (var1->var_part[i].cur_loc)
1276 && REG_P (var2->var_part[i].cur_loc)
1277 && (REGNO (var1->var_part[i].cur_loc)
1278 == REGNO (var2->var_part[i].cur_loc)))
1279 || rtx_equal_p (var1->var_part[i].cur_loc,
1280 var2->var_part[i].cur_loc)))
1283 if (variable_part_different_p (&var1->var_part[i], &var2->var_part[i]))
1285 if (variable_part_different_p (&var2->var_part[i], &var1->var_part[i]))
1291 /* Compare variable *SLOT with the same variable in hash table DATA
1292 and set DATAFLOW_SET_DIFFERENT_VALUE if they are different. */
1295 dataflow_set_different_1 (void **slot, void *data)
1297 htab_t htab = (htab_t) data;
1298 variable var1, var2;
1300 var1 = *(variable *) slot;
1301 var2 = htab_find_with_hash (htab, var1->decl,
1302 VARIABLE_HASH_VAL (var1->decl));
1305 dataflow_set_different_value = true;
1307 /* Stop traversing the hash table. */
1311 if (variable_different_p (var1, var2, false))
1313 dataflow_set_different_value = true;
1315 /* Stop traversing the hash table. */
1319 /* Continue traversing the hash table. */
1323 /* Compare variable *SLOT with the same variable in hash table DATA
1324 and set DATAFLOW_SET_DIFFERENT_VALUE if they are different. */
1327 dataflow_set_different_2 (void **slot, void *data)
1329 htab_t htab = (htab_t) data;
1330 variable var1, var2;
1332 var1 = *(variable *) slot;
1333 var2 = htab_find_with_hash (htab, var1->decl,
1334 VARIABLE_HASH_VAL (var1->decl));
1337 dataflow_set_different_value = true;
1339 /* Stop traversing the hash table. */
1343 /* If both variables are defined they have been already checked for
1345 gcc_assert (!variable_different_p (var1, var2, false));
1347 /* Continue traversing the hash table. */
1351 /* Return true if dataflow sets OLD_SET and NEW_SET differ. */
1354 dataflow_set_different (dataflow_set *old_set, dataflow_set *new_set)
1356 dataflow_set_different_value = false;
1358 htab_traverse (old_set->vars, dataflow_set_different_1, new_set->vars);
1359 if (!dataflow_set_different_value)
1361 /* We have compared the variables which are in both hash tables
1362 so now only check whether there are some variables in NEW_SET->VARS
1363 which are not in OLD_SET->VARS. */
1364 htab_traverse (new_set->vars, dataflow_set_different_2, old_set->vars);
1366 return dataflow_set_different_value;
1369 /* Free the contents of dataflow set SET. */
1372 dataflow_set_destroy (dataflow_set *set)
1376 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1377 attrs_list_clear (&set->regs[i]);
1379 htab_delete (set->vars);
1383 /* Return true if RTL X contains a SYMBOL_REF. */
1386 contains_symbol_ref (rtx x)
1395 code = GET_CODE (x);
1396 if (code == SYMBOL_REF)
1399 fmt = GET_RTX_FORMAT (code);
1400 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1404 if (contains_symbol_ref (XEXP (x, i)))
1407 else if (fmt[i] == 'E')
1410 for (j = 0; j < XVECLEN (x, i); j++)
1411 if (contains_symbol_ref (XVECEXP (x, i, j)))
1419 /* Shall EXPR be tracked? */
1422 track_expr_p (tree expr)
1427 /* If EXPR is not a parameter or a variable do not track it. */
1428 if (TREE_CODE (expr) != VAR_DECL && TREE_CODE (expr) != PARM_DECL)
1431 /* It also must have a name... */
1432 if (!DECL_NAME (expr))
1435 /* ... and a RTL assigned to it. */
1436 decl_rtl = DECL_RTL_IF_SET (expr);
1440 /* If this expression is really a debug alias of some other declaration, we
1441 don't need to track this expression if the ultimate declaration is
1444 if (DECL_DEBUG_EXPR_IS_FROM (realdecl) && DECL_DEBUG_EXPR (realdecl))
1446 realdecl = DECL_DEBUG_EXPR (realdecl);
1447 /* ??? We don't yet know how to emit DW_OP_piece for variable
1448 that has been SRA'ed. */
1449 if (!DECL_P (realdecl))
1453 /* Do not track EXPR if REALDECL it should be ignored for debugging
1455 if (DECL_IGNORED_P (realdecl))
1458 /* Do not track global variables until we are able to emit correct location
1460 if (TREE_STATIC (realdecl))
1463 /* When the EXPR is a DECL for alias of some variable (see example)
1464 the TREE_STATIC flag is not used. Disable tracking all DECLs whose
1465 DECL_RTL contains SYMBOL_REF.
1468 extern char **_dl_argv_internal __attribute__ ((alias ("_dl_argv")));
1471 if (MEM_P (decl_rtl)
1472 && contains_symbol_ref (XEXP (decl_rtl, 0)))
1475 /* If RTX is a memory it should not be very large (because it would be
1476 an array or struct). */
1477 if (MEM_P (decl_rtl))
1479 /* Do not track structures and arrays. */
1480 if (GET_MODE (decl_rtl) == BLKmode)
1482 if (MEM_SIZE (decl_rtl)
1483 && INTVAL (MEM_SIZE (decl_rtl)) > MAX_VAR_PARTS)
1490 /* Count uses (register and memory references) LOC which will be tracked.
1491 INSN is instruction which the LOC is part of. */
1494 count_uses (rtx *loc, void *insn)
1496 basic_block bb = BLOCK_FOR_INSN ((rtx) insn);
1500 gcc_assert (REGNO (*loc) < FIRST_PSEUDO_REGISTER);
1503 else if (MEM_P (*loc)
1505 && track_expr_p (MEM_EXPR (*loc)))
1513 /* Helper function for finding all uses of REG/MEM in X in insn INSN. */
1516 count_uses_1 (rtx *x, void *insn)
1518 for_each_rtx (x, count_uses, insn);
1521 /* Count stores (register and memory references) LOC which will be tracked.
1522 INSN is instruction which the LOC is part of. */
1525 count_stores (rtx loc, rtx expr ATTRIBUTE_UNUSED, void *insn)
1527 count_uses (&loc, insn);
1530 /* Add uses (register and memory references) LOC which will be tracked
1531 to VTI (bb)->mos. INSN is instruction which the LOC is part of. */
1534 add_uses (rtx *loc, void *insn)
1538 basic_block bb = BLOCK_FOR_INSN ((rtx) insn);
1539 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
1541 mo->type = ((REG_EXPR (*loc) && track_expr_p (REG_EXPR (*loc)))
1542 ? MO_USE : MO_USE_NO_VAR);
1544 mo->insn = (rtx) insn;
1546 else if (MEM_P (*loc)
1548 && track_expr_p (MEM_EXPR (*loc)))
1550 basic_block bb = BLOCK_FOR_INSN ((rtx) insn);
1551 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
1555 mo->insn = (rtx) insn;
1561 /* Helper function for finding all uses of REG/MEM in X in insn INSN. */
1564 add_uses_1 (rtx *x, void *insn)
1566 for_each_rtx (x, add_uses, insn);
1569 /* Add stores (register and memory references) LOC which will be tracked
1570 to VTI (bb)->mos. EXPR is the RTL expression containing the store.
1571 INSN is instruction which the LOC is part of. */
1574 add_stores (rtx loc, rtx expr, void *insn)
1578 basic_block bb = BLOCK_FOR_INSN ((rtx) insn);
1579 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
1581 mo->type = ((GET_CODE (expr) != CLOBBER && REG_EXPR (loc)
1582 && track_expr_p (REG_EXPR (loc)))
1583 ? MO_SET : MO_CLOBBER);
1585 mo->insn = (rtx) insn;
1587 else if (MEM_P (loc)
1589 && track_expr_p (MEM_EXPR (loc)))
1591 basic_block bb = BLOCK_FOR_INSN ((rtx) insn);
1592 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
1594 mo->type = GET_CODE (expr) == CLOBBER ? MO_CLOBBER : MO_SET;
1596 mo->insn = (rtx) insn;
1600 /* Compute the changes of variable locations in the basic block BB. */
1603 compute_bb_dataflow (basic_block bb)
1607 dataflow_set old_out;
1608 dataflow_set *in = &VTI (bb)->in;
1609 dataflow_set *out = &VTI (bb)->out;
1611 dataflow_set_init (&old_out, htab_elements (VTI (bb)->out.vars) + 3);
1612 dataflow_set_copy (&old_out, out);
1613 dataflow_set_copy (out, in);
1615 n = VTI (bb)->n_mos;
1616 for (i = 0; i < n; i++)
1618 switch (VTI (bb)->mos[i].type)
1621 for (r = 0; r < FIRST_PSEUDO_REGISTER; r++)
1622 if (TEST_HARD_REG_BIT (call_used_reg_set, r))
1623 var_regno_delete (out, r);
1629 rtx loc = VTI (bb)->mos[i].u.loc;
1632 var_reg_delete_and_set (out, loc);
1633 else if (MEM_P (loc))
1634 var_mem_delete_and_set (out, loc);
1641 rtx loc = VTI (bb)->mos[i].u.loc;
1644 var_reg_delete (out, loc);
1645 else if (MEM_P (loc))
1646 var_mem_delete (out, loc);
1654 out->stack_adjust += VTI (bb)->mos[i].u.adjust;
1655 base = gen_rtx_MEM (Pmode, plus_constant (stack_pointer_rtx,
1656 out->stack_adjust));
1657 set_frame_base_location (out, base);
1663 changed = dataflow_set_different (&old_out, out);
1664 dataflow_set_destroy (&old_out);
1668 /* Find the locations of variables in the whole function. */
1671 vt_find_locations (void)
1673 fibheap_t worklist, pending, fibheap_swap;
1674 sbitmap visited, in_worklist, in_pending, sbitmap_swap;
1681 /* Compute reverse completion order of depth first search of the CFG
1682 so that the data-flow runs faster. */
1683 rc_order = xmalloc (n_basic_blocks * sizeof (int));
1684 bb_order = xmalloc (last_basic_block * sizeof (int));
1685 flow_depth_first_order_compute (NULL, rc_order);
1686 for (i = 0; i < n_basic_blocks; i++)
1687 bb_order[rc_order[i]] = i;
1690 worklist = fibheap_new ();
1691 pending = fibheap_new ();
1692 visited = sbitmap_alloc (last_basic_block);
1693 in_worklist = sbitmap_alloc (last_basic_block);
1694 in_pending = sbitmap_alloc (last_basic_block);
1695 sbitmap_zero (in_worklist);
1698 fibheap_insert (pending, bb_order[bb->index], bb);
1699 sbitmap_ones (in_pending);
1701 while (!fibheap_empty (pending))
1703 fibheap_swap = pending;
1705 worklist = fibheap_swap;
1706 sbitmap_swap = in_pending;
1707 in_pending = in_worklist;
1708 in_worklist = sbitmap_swap;
1710 sbitmap_zero (visited);
1712 while (!fibheap_empty (worklist))
1714 bb = fibheap_extract_min (worklist);
1715 RESET_BIT (in_worklist, bb->index);
1716 if (!TEST_BIT (visited, bb->index))
1721 SET_BIT (visited, bb->index);
1723 /* Calculate the IN set as union of predecessor OUT sets. */
1724 dataflow_set_clear (&VTI (bb)->in);
1725 FOR_EACH_EDGE (e, ei, bb->preds)
1727 dataflow_set_union (&VTI (bb)->in, &VTI (e->src)->out);
1730 changed = compute_bb_dataflow (bb);
1733 FOR_EACH_EDGE (e, ei, bb->succs)
1735 if (e->dest == EXIT_BLOCK_PTR)
1741 if (TEST_BIT (visited, e->dest->index))
1743 if (!TEST_BIT (in_pending, e->dest->index))
1745 /* Send E->DEST to next round. */
1746 SET_BIT (in_pending, e->dest->index);
1747 fibheap_insert (pending,
1748 bb_order[e->dest->index],
1752 else if (!TEST_BIT (in_worklist, e->dest->index))
1754 /* Add E->DEST to current round. */
1755 SET_BIT (in_worklist, e->dest->index);
1756 fibheap_insert (worklist, bb_order[e->dest->index],
1766 fibheap_delete (worklist);
1767 fibheap_delete (pending);
1768 sbitmap_free (visited);
1769 sbitmap_free (in_worklist);
1770 sbitmap_free (in_pending);
1773 /* Print the content of the LIST to dump file. */
1776 dump_attrs_list (attrs list)
1778 for (; list; list = list->next)
1780 print_mem_expr (dump_file, list->decl);
1781 fprintf (dump_file, "+");
1782 fprintf (dump_file, HOST_WIDE_INT_PRINT_DEC, list->offset);
1784 fprintf (dump_file, "\n");
1787 /* Print the information about variable *SLOT to dump file. */
1790 dump_variable (void **slot, void *data ATTRIBUTE_UNUSED)
1792 variable var = *(variable *) slot;
1794 location_chain node;
1796 fprintf (dump_file, " name: %s\n",
1797 IDENTIFIER_POINTER (DECL_NAME (var->decl)));
1798 for (i = 0; i < var->n_var_parts; i++)
1800 fprintf (dump_file, " offset %ld\n",
1801 (long) var->var_part[i].offset);
1802 for (node = var->var_part[i].loc_chain; node; node = node->next)
1804 fprintf (dump_file, " ");
1805 print_rtl_single (dump_file, node->loc);
1809 /* Continue traversing the hash table. */
1813 /* Print the information about variables from hash table VARS to dump file. */
1816 dump_vars (htab_t vars)
1818 if (htab_elements (vars) > 0)
1820 fprintf (dump_file, "Variables:\n");
1821 htab_traverse (vars, dump_variable, NULL);
1825 /* Print the dataflow set SET to dump file. */
1828 dump_dataflow_set (dataflow_set *set)
1832 fprintf (dump_file, "Stack adjustment: ");
1833 fprintf (dump_file, HOST_WIDE_INT_PRINT_DEC, set->stack_adjust);
1834 fprintf (dump_file, "\n");
1835 for (i = 1; i < FIRST_PSEUDO_REGISTER; i++)
1839 fprintf (dump_file, "Reg %d:", i);
1840 dump_attrs_list (set->regs[i]);
1843 dump_vars (set->vars);
1844 fprintf (dump_file, "\n");
1847 /* Print the IN and OUT sets for each basic block to dump file. */
1850 dump_dataflow_sets (void)
1856 fprintf (dump_file, "\nBasic block %d:\n", bb->index);
1857 fprintf (dump_file, "IN:\n");
1858 dump_dataflow_set (&VTI (bb)->in);
1859 fprintf (dump_file, "OUT:\n");
1860 dump_dataflow_set (&VTI (bb)->out);
1864 /* Add variable VAR to the hash table of changed variables and
1865 if it has no locations delete it from hash table HTAB. */
1868 variable_was_changed (variable var, htab_t htab)
1870 hashval_t hash = VARIABLE_HASH_VAL (var->decl);
1876 slot = (variable *) htab_find_slot_with_hash (changed_variables,
1877 var->decl, hash, INSERT);
1879 if (htab && var->n_var_parts == 0)
1884 empty_var = pool_alloc (var_pool);
1885 empty_var->decl = var->decl;
1886 empty_var->refcount = 1;
1887 empty_var->n_var_parts = 0;
1890 old = htab_find_slot_with_hash (htab, var->decl, hash,
1893 htab_clear_slot (htab, old);
1903 if (var->n_var_parts == 0)
1905 void **slot = htab_find_slot_with_hash (htab, var->decl, hash,
1908 htab_clear_slot (htab, slot);
1913 /* Set the location of frame_base_decl to LOC in dataflow set SET. This
1914 function expects that frame_base_decl has already one location for offset 0
1915 in the variable table. */
1918 set_frame_base_location (dataflow_set *set, rtx loc)
1922 var = htab_find_with_hash (set->vars, frame_base_decl,
1923 VARIABLE_HASH_VAL (frame_base_decl));
1925 gcc_assert (var->n_var_parts == 1);
1926 gcc_assert (!var->var_part[0].offset);
1927 gcc_assert (var->var_part[0].loc_chain);
1929 /* If frame_base_decl is shared unshare it first. */
1930 if (var->refcount > 1)
1931 var = unshare_variable (set, var);
1933 var->var_part[0].loc_chain->loc = loc;
1934 var->var_part[0].cur_loc = loc;
1935 variable_was_changed (var, set->vars);
1938 /* Set the part of variable's location in the dataflow set SET. The variable
1939 part is specified by variable's declaration DECL and offset OFFSET and the
1940 part's location by LOC. */
1943 set_variable_part (dataflow_set *set, rtx loc, tree decl, HOST_WIDE_INT offset)
1946 location_chain node, next;
1947 location_chain *nextp;
1951 slot = htab_find_slot_with_hash (set->vars, decl,
1952 VARIABLE_HASH_VAL (decl), INSERT);
1955 /* Create new variable information. */
1956 var = pool_alloc (var_pool);
1959 var->n_var_parts = 1;
1960 var->var_part[0].offset = offset;
1961 var->var_part[0].loc_chain = NULL;
1962 var->var_part[0].cur_loc = NULL;
1968 var = (variable) *slot;
1970 /* Find the location part. */
1972 high = var->n_var_parts;
1975 pos = (low + high) / 2;
1976 if (var->var_part[pos].offset < offset)
1983 if (pos < var->n_var_parts && var->var_part[pos].offset == offset)
1985 node = var->var_part[pos].loc_chain;
1988 && ((REG_P (node->loc) && REG_P (loc)
1989 && REGNO (node->loc) == REGNO (loc))
1990 || rtx_equal_p (node->loc, loc)))
1992 /* LOC is in the beginning of the chain so we have nothing
1998 /* We have to make a copy of a shared variable. */
1999 if (var->refcount > 1)
2000 var = unshare_variable (set, var);
2005 /* We have not found the location part, new one will be created. */
2007 /* We have to make a copy of the shared variable. */
2008 if (var->refcount > 1)
2009 var = unshare_variable (set, var);
2011 /* We track only variables whose size is <= MAX_VAR_PARTS bytes
2012 thus there are at most MAX_VAR_PARTS different offsets. */
2013 gcc_assert (var->n_var_parts < MAX_VAR_PARTS);
2015 /* We have to move the elements of array starting at index low to the
2017 for (high = var->n_var_parts; high > low; high--)
2018 var->var_part[high] = var->var_part[high - 1];
2021 var->var_part[pos].offset = offset;
2022 var->var_part[pos].loc_chain = NULL;
2023 var->var_part[pos].cur_loc = NULL;
2027 /* Delete the location from the list. */
2028 nextp = &var->var_part[pos].loc_chain;
2029 for (node = var->var_part[pos].loc_chain; node; node = next)
2032 if ((REG_P (node->loc) && REG_P (loc)
2033 && REGNO (node->loc) == REGNO (loc))
2034 || rtx_equal_p (node->loc, loc))
2036 pool_free (loc_chain_pool, node);
2041 nextp = &node->next;
2044 /* Add the location to the beginning. */
2045 node = pool_alloc (loc_chain_pool);
2047 node->next = var->var_part[pos].loc_chain;
2048 var->var_part[pos].loc_chain = node;
2050 /* If no location was emitted do so. */
2051 if (var->var_part[pos].cur_loc == NULL)
2053 var->var_part[pos].cur_loc = loc;
2054 variable_was_changed (var, set->vars);
2058 /* Delete the part of variable's location from dataflow set SET. The variable
2059 part is specified by variable's declaration DECL and offset OFFSET and the
2060 part's location by LOC. */
2063 delete_variable_part (dataflow_set *set, rtx loc, tree decl,
2064 HOST_WIDE_INT offset)
2069 slot = htab_find_slot_with_hash (set->vars, decl, VARIABLE_HASH_VAL (decl),
2073 variable var = (variable) *slot;
2075 /* Find the location part. */
2077 high = var->n_var_parts;
2080 pos = (low + high) / 2;
2081 if (var->var_part[pos].offset < offset)
2088 if (pos < var->n_var_parts && var->var_part[pos].offset == offset)
2090 location_chain node, next;
2091 location_chain *nextp;
2094 if (var->refcount > 1)
2096 /* If the variable contains the location part we have to
2097 make a copy of the variable. */
2098 for (node = var->var_part[pos].loc_chain; node;
2101 if ((REG_P (node->loc) && REG_P (loc)
2102 && REGNO (node->loc) == REGNO (loc))
2103 || rtx_equal_p (node->loc, loc))
2105 var = unshare_variable (set, var);
2111 /* Delete the location part. */
2112 nextp = &var->var_part[pos].loc_chain;
2113 for (node = *nextp; node; node = next)
2116 if ((REG_P (node->loc) && REG_P (loc)
2117 && REGNO (node->loc) == REGNO (loc))
2118 || rtx_equal_p (node->loc, loc))
2120 pool_free (loc_chain_pool, node);
2125 nextp = &node->next;
2128 /* If we have deleted the location which was last emitted
2129 we have to emit new location so add the variable to set
2130 of changed variables. */
2131 if (var->var_part[pos].cur_loc
2133 && REG_P (var->var_part[pos].cur_loc)
2134 && REGNO (loc) == REGNO (var->var_part[pos].cur_loc))
2135 || rtx_equal_p (loc, var->var_part[pos].cur_loc)))
2138 if (var->var_part[pos].loc_chain)
2139 var->var_part[pos].cur_loc = var->var_part[pos].loc_chain->loc;
2144 if (var->var_part[pos].loc_chain == NULL)
2147 while (pos < var->n_var_parts)
2149 var->var_part[pos] = var->var_part[pos + 1];
2154 variable_was_changed (var, set->vars);
2159 /* Emit the NOTE_INSN_VAR_LOCATION for variable *VARP. DATA contains
2160 additional parameters: WHERE specifies whether the note shall be emitted
2161 before of after instruction INSN. */
2164 emit_note_insn_var_location (void **varp, void *data)
2166 variable var = *(variable *) varp;
2167 rtx insn = ((emit_note_data *)data)->insn;
2168 enum emit_note_where where = ((emit_note_data *)data)->where;
2172 HOST_WIDE_INT last_limit;
2173 tree type_size_unit;
2175 gcc_assert (var->decl);
2179 for (i = 0; i < var->n_var_parts; i++)
2181 if (last_limit < var->var_part[i].offset)
2187 = (var->var_part[i].offset
2188 + GET_MODE_SIZE (GET_MODE (var->var_part[i].loc_chain->loc)));
2190 type_size_unit = TYPE_SIZE_UNIT (TREE_TYPE (var->decl));
2191 if ((unsigned HOST_WIDE_INT) last_limit < TREE_INT_CST_LOW (type_size_unit))
2194 if (where == EMIT_NOTE_AFTER_INSN)
2195 note = emit_note_after (NOTE_INSN_VAR_LOCATION, insn);
2197 note = emit_note_before (NOTE_INSN_VAR_LOCATION, insn);
2201 NOTE_VAR_LOCATION (note) = gen_rtx_VAR_LOCATION (VOIDmode, var->decl,
2204 else if (var->n_var_parts == 1)
2207 = gen_rtx_EXPR_LIST (VOIDmode,
2208 var->var_part[0].loc_chain->loc,
2209 GEN_INT (var->var_part[0].offset));
2211 NOTE_VAR_LOCATION (note) = gen_rtx_VAR_LOCATION (VOIDmode, var->decl,
2214 else if (var->n_var_parts)
2216 rtx argp[MAX_VAR_PARTS];
2219 for (i = 0; i < var->n_var_parts; i++)
2220 argp[i] = gen_rtx_EXPR_LIST (VOIDmode, var->var_part[i].loc_chain->loc,
2221 GEN_INT (var->var_part[i].offset));
2222 parallel = gen_rtx_PARALLEL (VOIDmode,
2223 gen_rtvec_v (var->n_var_parts, argp));
2224 NOTE_VAR_LOCATION (note) = gen_rtx_VAR_LOCATION (VOIDmode, var->decl,
2228 htab_clear_slot (changed_variables, varp);
2230 /* When there are no location parts the variable has been already
2231 removed from hash table and a new empty variable was created.
2232 Free the empty variable. */
2233 if (var->n_var_parts == 0)
2235 pool_free (var_pool, var);
2238 /* Continue traversing the hash table. */
2242 /* Emit NOTE_INSN_VAR_LOCATION note for each variable from a chain
2243 CHANGED_VARIABLES and delete this chain. WHERE specifies whether the notes
2244 shall be emitted before of after instruction INSN. */
2247 emit_notes_for_changes (rtx insn, enum emit_note_where where)
2249 emit_note_data data;
2253 htab_traverse (changed_variables, emit_note_insn_var_location, &data);
2256 /* Add variable *SLOT to the chain CHANGED_VARIABLES if it differs from the
2257 same variable in hash table DATA or is not there at all. */
2260 emit_notes_for_differences_1 (void **slot, void *data)
2262 htab_t new_vars = (htab_t) data;
2263 variable old_var, new_var;
2265 old_var = *(variable *) slot;
2266 new_var = htab_find_with_hash (new_vars, old_var->decl,
2267 VARIABLE_HASH_VAL (old_var->decl));
2271 /* Variable has disappeared. */
2274 empty_var = pool_alloc (var_pool);
2275 empty_var->decl = old_var->decl;
2276 empty_var->refcount = 1;
2277 empty_var->n_var_parts = 0;
2278 variable_was_changed (empty_var, NULL);
2280 else if (variable_different_p (old_var, new_var, true))
2282 variable_was_changed (new_var, NULL);
2285 /* Continue traversing the hash table. */
2289 /* Add variable *SLOT to the chain CHANGED_VARIABLES if it is not in hash
2293 emit_notes_for_differences_2 (void **slot, void *data)
2295 htab_t old_vars = (htab_t) data;
2296 variable old_var, new_var;
2298 new_var = *(variable *) slot;
2299 old_var = htab_find_with_hash (old_vars, new_var->decl,
2300 VARIABLE_HASH_VAL (new_var->decl));
2303 /* Variable has appeared. */
2304 variable_was_changed (new_var, NULL);
2307 /* Continue traversing the hash table. */
2311 /* Emit notes before INSN for differences between dataflow sets OLD_SET and
2315 emit_notes_for_differences (rtx insn, dataflow_set *old_set,
2316 dataflow_set *new_set)
2318 htab_traverse (old_set->vars, emit_notes_for_differences_1, new_set->vars);
2319 htab_traverse (new_set->vars, emit_notes_for_differences_2, old_set->vars);
2320 emit_notes_for_changes (insn, EMIT_NOTE_BEFORE_INSN);
2323 /* Emit the notes for changes of location parts in the basic block BB. */
2326 emit_notes_in_bb (basic_block bb)
2331 dataflow_set_init (&set, htab_elements (VTI (bb)->in.vars) + 3);
2332 dataflow_set_copy (&set, &VTI (bb)->in);
2334 for (i = 0; i < VTI (bb)->n_mos; i++)
2336 rtx insn = VTI (bb)->mos[i].insn;
2338 switch (VTI (bb)->mos[i].type)
2344 for (r = 0; r < FIRST_PSEUDO_REGISTER; r++)
2345 if (TEST_HARD_REG_BIT (call_used_reg_set, r))
2347 var_regno_delete (&set, r);
2349 emit_notes_for_changes (insn, EMIT_NOTE_AFTER_INSN);
2356 rtx loc = VTI (bb)->mos[i].u.loc;
2359 var_reg_delete_and_set (&set, loc);
2361 var_mem_delete_and_set (&set, loc);
2363 if (VTI (bb)->mos[i].type == MO_USE)
2364 emit_notes_for_changes (insn, EMIT_NOTE_BEFORE_INSN);
2366 emit_notes_for_changes (insn, EMIT_NOTE_AFTER_INSN);
2373 rtx loc = VTI (bb)->mos[i].u.loc;
2376 var_reg_delete (&set, loc);
2378 var_mem_delete (&set, loc);
2380 if (VTI (bb)->mos[i].type == MO_USE_NO_VAR)
2381 emit_notes_for_changes (insn, EMIT_NOTE_BEFORE_INSN);
2383 emit_notes_for_changes (insn, EMIT_NOTE_AFTER_INSN);
2391 set.stack_adjust += VTI (bb)->mos[i].u.adjust;
2392 base = gen_rtx_MEM (Pmode, plus_constant (stack_pointer_rtx,
2394 set_frame_base_location (&set, base);
2395 emit_notes_for_changes (insn, EMIT_NOTE_AFTER_INSN);
2400 dataflow_set_destroy (&set);
2403 /* Emit notes for the whole function. */
2406 vt_emit_notes (void)
2409 dataflow_set *last_out;
2412 gcc_assert (!htab_elements (changed_variables));
2414 /* Enable emitting notes by functions (mainly by set_variable_part and
2415 delete_variable_part). */
2418 dataflow_set_init (&empty, 7);
2423 /* Emit the notes for changes of variable locations between two
2424 subsequent basic blocks. */
2425 emit_notes_for_differences (BB_HEAD (bb), last_out, &VTI (bb)->in);
2427 /* Emit the notes for the changes in the basic block itself. */
2428 emit_notes_in_bb (bb);
2430 last_out = &VTI (bb)->out;
2432 dataflow_set_destroy (&empty);
2436 /* If there is a declaration and offset associated with register/memory RTL
2437 assign declaration to *DECLP and offset to *OFFSETP, and return true. */
2440 vt_get_decl_and_offset (rtx rtl, tree *declp, HOST_WIDE_INT *offsetp)
2444 if (REG_ATTRS (rtl))
2446 *declp = REG_EXPR (rtl);
2447 *offsetp = REG_OFFSET (rtl);
2451 else if (MEM_P (rtl))
2453 if (MEM_ATTRS (rtl))
2455 *declp = MEM_EXPR (rtl);
2456 *offsetp = MEM_OFFSET (rtl) ? INTVAL (MEM_OFFSET (rtl)) : 0;
2463 /* Insert function parameters to IN and OUT sets of ENTRY_BLOCK. */
2466 vt_add_function_parameters (void)
2470 for (parm = DECL_ARGUMENTS (current_function_decl);
2471 parm; parm = TREE_CHAIN (parm))
2473 rtx decl_rtl = DECL_RTL_IF_SET (parm);
2474 rtx incoming = DECL_INCOMING_RTL (parm);
2476 HOST_WIDE_INT offset;
2479 if (TREE_CODE (parm) != PARM_DECL)
2482 if (!DECL_NAME (parm))
2485 if (!decl_rtl || !incoming)
2488 if (GET_MODE (decl_rtl) == BLKmode || GET_MODE (incoming) == BLKmode)
2491 if (!vt_get_decl_and_offset (incoming, &decl, &offset))
2492 if (!vt_get_decl_and_offset (decl_rtl, &decl, &offset))
2498 gcc_assert (parm == decl);
2500 incoming = eliminate_regs (incoming, 0, NULL_RTX);
2501 out = &VTI (ENTRY_BLOCK_PTR)->out;
2503 if (REG_P (incoming))
2505 gcc_assert (REGNO (incoming) < FIRST_PSEUDO_REGISTER);
2506 attrs_list_insert (&out->regs[REGNO (incoming)],
2507 parm, offset, incoming);
2508 set_variable_part (out, incoming, parm, offset);
2510 else if (MEM_P (incoming))
2512 set_variable_part (out, incoming, parm, offset);
2517 /* Allocate and initialize the data structures for variable tracking
2518 and parse the RTL to get the micro operations. */
2521 vt_initialize (void)
2525 alloc_aux_for_blocks (sizeof (struct variable_tracking_info_def));
2530 HOST_WIDE_INT pre, post;
2532 /* Count the number of micro operations. */
2533 VTI (bb)->n_mos = 0;
2534 for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb));
2535 insn = NEXT_INSN (insn))
2539 if (!frame_pointer_needed)
2541 insn_stack_adjust_offset_pre_post (insn, &pre, &post);
2547 note_uses (&PATTERN (insn), count_uses_1, insn);
2548 note_stores (PATTERN (insn), count_stores, insn);
2554 /* Add the micro-operations to the array. */
2555 VTI (bb)->mos = xmalloc (VTI (bb)->n_mos
2556 * sizeof (struct micro_operation_def));
2557 VTI (bb)->n_mos = 0;
2558 for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb));
2559 insn = NEXT_INSN (insn))
2565 if (!frame_pointer_needed)
2567 insn_stack_adjust_offset_pre_post (insn, &pre, &post);
2570 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
2572 mo->type = MO_ADJUST;
2578 n1 = VTI (bb)->n_mos;
2579 note_uses (&PATTERN (insn), add_uses_1, insn);
2580 n2 = VTI (bb)->n_mos - 1;
2582 /* Order the MO_USEs to be before MO_USE_NO_VARs. */
2585 while (n1 < n2 && VTI (bb)->mos[n1].type == MO_USE)
2587 while (n1 < n2 && VTI (bb)->mos[n2].type == MO_USE_NO_VAR)
2593 sw = VTI (bb)->mos[n1];
2594 VTI (bb)->mos[n1] = VTI (bb)->mos[n2];
2595 VTI (bb)->mos[n2] = sw;
2601 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
2607 n1 = VTI (bb)->n_mos;
2608 note_stores (PATTERN (insn), add_stores, insn);
2609 n2 = VTI (bb)->n_mos - 1;
2611 /* Order the MO_SETs to be before MO_CLOBBERs. */
2614 while (n1 < n2 && VTI (bb)->mos[n1].type == MO_SET)
2616 while (n1 < n2 && VTI (bb)->mos[n2].type == MO_CLOBBER)
2622 sw = VTI (bb)->mos[n1];
2623 VTI (bb)->mos[n1] = VTI (bb)->mos[n2];
2624 VTI (bb)->mos[n2] = sw;
2628 if (!frame_pointer_needed && post)
2630 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
2632 mo->type = MO_ADJUST;
2633 mo->u.adjust = post;
2640 /* Init the IN and OUT sets. */
2643 VTI (bb)->visited = false;
2644 dataflow_set_init (&VTI (bb)->in, 7);
2645 dataflow_set_init (&VTI (bb)->out, 7);
2648 attrs_pool = create_alloc_pool ("attrs_def pool",
2649 sizeof (struct attrs_def), 1024);
2650 var_pool = create_alloc_pool ("variable_def pool",
2651 sizeof (struct variable_def), 64);
2652 loc_chain_pool = create_alloc_pool ("location_chain_def pool",
2653 sizeof (struct location_chain_def),
2655 changed_variables = htab_create (10, variable_htab_hash, variable_htab_eq,
2657 vt_add_function_parameters ();
2659 if (!frame_pointer_needed)
2663 /* Create fake variable for tracking stack pointer changes. */
2664 frame_base_decl = make_node (VAR_DECL);
2665 DECL_NAME (frame_base_decl) = get_identifier ("___frame_base_decl");
2666 TREE_TYPE (frame_base_decl) = char_type_node;
2667 DECL_ARTIFICIAL (frame_base_decl) = 1;
2668 DECL_IGNORED_P (frame_base_decl) = 1;
2670 /* Set its initial "location". */
2671 frame_stack_adjust = -prologue_stack_adjust ();
2672 base = gen_rtx_MEM (Pmode, plus_constant (stack_pointer_rtx,
2673 frame_stack_adjust));
2674 set_variable_part (&VTI (ENTRY_BLOCK_PTR)->out, base, frame_base_decl, 0);
2678 frame_base_decl = NULL;
2682 /* Free the data structures needed for variable tracking. */
2691 free (VTI (bb)->mos);
2696 dataflow_set_destroy (&VTI (bb)->in);
2697 dataflow_set_destroy (&VTI (bb)->out);
2699 free_aux_for_blocks ();
2700 free_alloc_pool (attrs_pool);
2701 free_alloc_pool (var_pool);
2702 free_alloc_pool (loc_chain_pool);
2703 htab_delete (changed_variables);
2706 /* The entry point to variable tracking pass. */
2709 variable_tracking_main (void)
2711 if (n_basic_blocks > 500 && n_edges / n_basic_blocks >= 20)
2714 mark_dfs_back_edges ();
2716 if (!frame_pointer_needed)
2718 if (!vt_stack_adjustments ())
2725 vt_find_locations ();
2730 dump_dataflow_sets ();
2731 dump_flow_info (dump_file);