1 /* Variable tracking routines for the GNU compiler.
2 Copyright (C) 2002, 2003, 2004 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 /* Number of variable parts. */
239 /* The variable parts. */
240 variable_part var_part[MAX_VAR_PARTS];
243 /* Hash function for DECL for VARIABLE_HTAB. */
244 #define VARIABLE_HASH_VAL(decl) ((size_t) (decl))
246 /* Pointer to the BB's information specific to variable tracking pass. */
247 #define VTI(BB) ((variable_tracking_info) (BB)->aux)
249 /* Alloc pool for struct attrs_def. */
250 static alloc_pool attrs_pool;
252 /* Alloc pool for struct variable_def. */
253 static alloc_pool var_pool;
255 /* Alloc pool for struct location_chain_def. */
256 static alloc_pool loc_chain_pool;
258 /* Changed variables, notes will be emitted for them. */
259 static htab_t changed_variables;
261 /* Shall notes be emitted? */
262 static bool emit_notes;
264 /* Fake variable for stack pointer. */
265 GTY(()) tree frame_base_decl;
267 /* Local function prototypes. */
268 static void stack_adjust_offset_pre_post (rtx, HOST_WIDE_INT *,
270 static void insn_stack_adjust_offset_pre_post (rtx, HOST_WIDE_INT *,
272 static void bb_stack_adjust_offset (basic_block);
273 static HOST_WIDE_INT prologue_stack_adjust (void);
274 static bool vt_stack_adjustments (void);
275 static rtx adjust_stack_reference (rtx, HOST_WIDE_INT);
276 static hashval_t variable_htab_hash (const void *);
277 static int variable_htab_eq (const void *, const void *);
278 static void variable_htab_free (void *);
280 static void init_attrs_list_set (attrs *);
281 static void attrs_list_clear (attrs *);
282 static attrs attrs_list_member (attrs, tree, HOST_WIDE_INT);
283 static void attrs_list_insert (attrs *, tree, HOST_WIDE_INT, rtx);
284 static void attrs_list_copy (attrs *, attrs);
285 static void attrs_list_union (attrs *, attrs);
287 static void vars_clear (htab_t);
288 static int vars_copy_1 (void **, void *);
289 static void vars_copy (htab_t, htab_t);
290 static void var_reg_delete_and_set (dataflow_set *, rtx);
291 static void var_reg_delete (dataflow_set *, rtx);
292 static void var_regno_delete (dataflow_set *, int);
293 static void var_mem_delete_and_set (dataflow_set *, rtx);
294 static void var_mem_delete (dataflow_set *, rtx);
296 static void dataflow_set_init (dataflow_set *, int);
297 static void dataflow_set_clear (dataflow_set *);
298 static void dataflow_set_copy (dataflow_set *, dataflow_set *);
299 static int variable_union_info_cmp_pos (const void *, const void *);
300 static int variable_union (void **, void *);
301 static void dataflow_set_union (dataflow_set *, dataflow_set *);
302 static bool variable_part_different_p (variable_part *, variable_part *);
303 static bool variable_different_p (variable, variable);
304 static int dataflow_set_different_1 (void **, void *);
305 static int dataflow_set_different_2 (void **, void *);
306 static bool dataflow_set_different (dataflow_set *, dataflow_set *);
307 static void dataflow_set_destroy (dataflow_set *);
309 static bool contains_symbol_ref (rtx);
310 static bool track_expr_p (tree);
311 static int count_uses (rtx *, void *);
312 static void count_uses_1 (rtx *, void *);
313 static void count_stores (rtx, rtx, void *);
314 static int add_uses (rtx *, void *);
315 static void add_uses_1 (rtx *, void *);
316 static void add_stores (rtx, rtx, void *);
317 static bool compute_bb_dataflow (basic_block);
318 static void vt_find_locations (void);
320 static void dump_attrs_list (attrs);
321 static int dump_variable (void **, void *);
322 static void dump_vars (htab_t);
323 static void dump_dataflow_set (dataflow_set *);
324 static void dump_dataflow_sets (void);
326 static void variable_was_changed (variable, htab_t);
327 static void set_frame_base_location (dataflow_set *, rtx);
328 static void set_variable_part (dataflow_set *, rtx, tree, HOST_WIDE_INT);
329 static void delete_variable_part (dataflow_set *, rtx, tree, HOST_WIDE_INT);
330 static int emit_note_insn_var_location (void **, void *);
331 static void emit_notes_for_changes (rtx, enum emit_note_where);
332 static int emit_notes_for_differences_1 (void **, void *);
333 static int emit_notes_for_differences_2 (void **, void *);
334 static void emit_notes_for_differences (rtx, dataflow_set *, dataflow_set *);
335 static void emit_notes_in_bb (basic_block);
336 static void vt_emit_notes (void);
338 static bool vt_get_decl_and_offset (rtx, tree *, HOST_WIDE_INT *);
339 static void vt_add_function_parameters (void);
340 static void vt_initialize (void);
341 static void vt_finalize (void);
343 /* Given a SET, calculate the amount of stack adjustment it contains
344 PRE- and POST-modifying stack pointer.
345 This function is similar to stack_adjust_offset. */
348 stack_adjust_offset_pre_post (rtx pattern, HOST_WIDE_INT *pre,
351 rtx src = SET_SRC (pattern);
352 rtx dest = SET_DEST (pattern);
355 if (dest == stack_pointer_rtx)
357 /* (set (reg sp) (plus (reg sp) (const_int))) */
358 code = GET_CODE (src);
359 if (! (code == PLUS || code == MINUS)
360 || XEXP (src, 0) != stack_pointer_rtx
361 || GET_CODE (XEXP (src, 1)) != CONST_INT)
365 *post += INTVAL (XEXP (src, 1));
367 *post -= INTVAL (XEXP (src, 1));
369 else if (GET_CODE (dest) == MEM)
371 /* (set (mem (pre_dec (reg sp))) (foo)) */
372 src = XEXP (dest, 0);
373 code = GET_CODE (src);
379 if (XEXP (src, 0) == stack_pointer_rtx)
381 rtx val = XEXP (XEXP (src, 1), 1);
382 /* We handle only adjustments by constant amount. */
383 if (GET_CODE (XEXP (src, 1)) != PLUS ||
384 GET_CODE (val) != CONST_INT)
386 if (code == PRE_MODIFY)
387 *pre -= INTVAL (val);
389 *post -= INTVAL (val);
395 if (XEXP (src, 0) == stack_pointer_rtx)
397 *pre += GET_MODE_SIZE (GET_MODE (dest));
403 if (XEXP (src, 0) == stack_pointer_rtx)
405 *post += GET_MODE_SIZE (GET_MODE (dest));
411 if (XEXP (src, 0) == stack_pointer_rtx)
413 *pre -= GET_MODE_SIZE (GET_MODE (dest));
419 if (XEXP (src, 0) == stack_pointer_rtx)
421 *post -= GET_MODE_SIZE (GET_MODE (dest));
432 /* Given an INSN, calculate the amount of stack adjustment it contains
433 PRE- and POST-modifying stack pointer. */
436 insn_stack_adjust_offset_pre_post (rtx insn, HOST_WIDE_INT *pre,
442 if (GET_CODE (PATTERN (insn)) == SET)
443 stack_adjust_offset_pre_post (PATTERN (insn), pre, post);
444 else if (GET_CODE (PATTERN (insn)) == PARALLEL
445 || GET_CODE (PATTERN (insn)) == SEQUENCE)
449 /* There may be stack adjustments inside compound insns. Search
451 for ( i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
452 if (GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == SET)
453 stack_adjust_offset_pre_post (XVECEXP (PATTERN (insn), 0, i),
458 /* Compute stack adjustment in basic block BB. */
461 bb_stack_adjust_offset (basic_block bb)
463 HOST_WIDE_INT offset;
466 offset = VTI (bb)->in.stack_adjust;
467 for (i = 0; i < VTI (bb)->n_mos; i++)
469 if (VTI (bb)->mos[i].type == MO_ADJUST)
470 offset += VTI (bb)->mos[i].u.adjust;
471 else if (VTI (bb)->mos[i].type != MO_CALL)
473 if (GET_CODE (VTI (bb)->mos[i].u.loc) == MEM)
475 VTI (bb)->mos[i].u.loc
476 = adjust_stack_reference (VTI (bb)->mos[i].u.loc, -offset);
480 VTI (bb)->out.stack_adjust = offset;
483 /* Compute stack adjustment caused by function prolog. */
486 prologue_stack_adjust (void)
488 HOST_WIDE_INT offset = 0;
489 basic_block bb = ENTRY_BLOCK_PTR->next_bb;
496 end = NEXT_INSN (BB_END (bb));
497 for (insn = BB_HEAD (bb); insn != end; insn = NEXT_INSN (insn))
499 if (GET_CODE (insn) == NOTE
500 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_PROLOGUE_END)
507 insn_stack_adjust_offset_pre_post (insn, &tmp, &tmp);
515 /* Compute stack adjustments for all blocks by traversing DFS tree.
516 Return true when the adjustments on all incoming edges are consistent.
517 Heavily borrowed from flow_depth_first_order_compute. */
520 vt_stack_adjustments (void)
525 /* Initialize entry block. */
526 VTI (ENTRY_BLOCK_PTR)->visited = true;
527 VTI (ENTRY_BLOCK_PTR)->out.stack_adjust = 0;
529 /* Allocate stack for back-tracking up CFG. */
530 stack = xmalloc ((n_basic_blocks + 1) * sizeof (edge));
533 /* Push the first edge on to the stack. */
534 stack[sp++] = ENTRY_BLOCK_PTR->succ;
542 /* Look at the edge on the top of the stack. */
547 /* Check if the edge destination has been visited yet. */
548 if (!VTI (dest)->visited)
550 VTI (dest)->visited = true;
551 VTI (dest)->in.stack_adjust = VTI (src)->out.stack_adjust;
552 bb_stack_adjust_offset (dest);
555 /* Since the DEST node has been visited for the first
556 time, check its successors. */
557 stack[sp++] = dest->succ;
561 /* Check whether the adjustments on the edges are the same. */
562 if (VTI (dest)->in.stack_adjust != VTI (src)->out.stack_adjust)
569 /* Go to the next edge. */
570 stack[sp - 1] = e->succ_next;
572 /* Return to previous level if there are no more edges. */
581 /* Adjust stack reference MEM by ADJUSTMENT bytes and return the new rtx. */
584 adjust_stack_reference (rtx mem, HOST_WIDE_INT adjustment)
589 adjusted_mem = copy_rtx (mem);
590 XEXP (adjusted_mem, 0) = replace_rtx (XEXP (adjusted_mem, 0),
592 gen_rtx_PLUS (Pmode, stack_pointer_rtx,
593 GEN_INT (adjustment)));
594 tmp = simplify_rtx (XEXP (adjusted_mem, 0));
596 XEXP (adjusted_mem, 0) = tmp;
601 /* The hash function for variable_htab, computes the hash value
602 from the declaration of variable X. */
605 variable_htab_hash (const void *x)
607 const variable v = (const variable) x;
609 return (VARIABLE_HASH_VAL (v->decl));
612 /* Compare the declaration of variable X with declaration Y. */
615 variable_htab_eq (const void *x, const void *y)
617 const variable v = (const variable) x;
618 const tree decl = (const tree) y;
620 return (VARIABLE_HASH_VAL (v->decl) == VARIABLE_HASH_VAL (decl));
623 /* Free the element of VARIABLE_HTAB (its type is struct variable_def). */
626 variable_htab_free (void *elem)
629 variable var = (variable) elem;
630 location_chain node, next;
632 for (i = 0; i < var->n_var_parts; i++)
634 for (node = var->var_part[i].loc_chain; node; node = next)
637 pool_free (loc_chain_pool, node);
639 var->var_part[i].loc_chain = NULL;
641 pool_free (var_pool, var);
644 /* Initialize the set (array) SET of attrs to empty lists. */
647 init_attrs_list_set (attrs *set)
651 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
655 /* Make the list *LISTP empty. */
658 attrs_list_clear (attrs *listp)
662 for (list = *listp; list; list = next)
665 pool_free (attrs_pool, list);
670 /* Return true if the pair of DECL and OFFSET is the member of the LIST. */
673 attrs_list_member (attrs list, tree decl, HOST_WIDE_INT offset)
675 for (; list; list = list->next)
676 if (list->decl == decl && list->offset == offset)
681 /* Insert the triplet DECL, OFFSET, LOC to the list *LISTP. */
684 attrs_list_insert (attrs *listp, tree decl, HOST_WIDE_INT offset, rtx loc)
688 list = pool_alloc (attrs_pool);
691 list->offset = offset;
696 /* Copy all nodes from SRC and create a list *DSTP of the copies. */
699 attrs_list_copy (attrs *dstp, attrs src)
703 attrs_list_clear (dstp);
704 for (; src; src = src->next)
706 n = pool_alloc (attrs_pool);
709 n->offset = src->offset;
715 /* Add all nodes from SRC which are not in *DSTP to *DSTP. */
718 attrs_list_union (attrs *dstp, attrs src)
720 for (; src; src = src->next)
722 if (!attrs_list_member (*dstp, src->decl, src->offset))
723 attrs_list_insert (dstp, src->decl, src->offset, src->loc);
727 /* Delete all variables from hash table VARS. */
730 vars_clear (htab_t vars)
735 /* Copy one variable from *SLOT to hash table DATA. */
738 vars_copy_1 (void **slot, void *data)
740 htab_t dst = (htab_t) data;
741 variable src, *dstp, var;
744 src = *(variable *) slot;
745 dstp = (variable *) htab_find_slot_with_hash (dst, src->decl,
746 VARIABLE_HASH_VAL (src->decl),
748 var = pool_alloc (var_pool);
749 var->decl = src->decl;
750 var->n_var_parts = src->n_var_parts;
751 *dstp = (void *) var;
753 for (i = 0; i < var->n_var_parts; i++)
756 location_chain *nextp;
758 var->var_part[i].offset = src->var_part[i].offset;
759 nextp = &var->var_part[i].loc_chain;
760 for (node = src->var_part[i].loc_chain; node; node = node->next)
762 location_chain new_lc;
764 new_lc = pool_alloc (loc_chain_pool);
766 new_lc->loc = node->loc;
769 nextp = &new_lc->next;
772 /* We are at the basic block boundary when copying variable description
773 so set the CUR_LOC to be the first element of the chain. */
774 if (var->var_part[i].loc_chain)
775 var->var_part[i].cur_loc = var->var_part[i].loc_chain->loc;
777 var->var_part[i].cur_loc = NULL;
780 /* Continue traversing the hash table. */
784 /* Copy all variables from hash table SRC to hash table DST. */
787 vars_copy (htab_t dst, htab_t src)
790 htab_traverse (src, vars_copy_1, dst);
793 /* Delete current content of register LOC in dataflow set SET
794 and set the register to contain REG_EXPR (LOC), REG_OFFSET (LOC). */
797 var_reg_delete_and_set (dataflow_set *set, rtx loc)
799 tree decl = REG_EXPR (loc);
800 HOST_WIDE_INT offset = REG_OFFSET (loc);
804 nextp = &set->regs[REGNO (loc)];
805 for (node = *nextp; node; node = next)
808 if (node->decl != decl || node->offset != offset)
810 delete_variable_part (set, node->loc, node->decl, node->offset);
811 pool_free (attrs_pool, node);
820 if (set->regs[REGNO (loc)] == NULL)
821 attrs_list_insert (&set->regs[REGNO (loc)], decl, offset, loc);
822 set_variable_part (set, loc, decl, offset);
825 /* Delete current content of register LOC in dataflow set SET. */
828 var_reg_delete (dataflow_set *set, rtx loc)
830 attrs *reg = &set->regs[REGNO (loc)];
833 for (node = *reg; node; node = next)
836 delete_variable_part (set, node->loc, node->decl, node->offset);
837 pool_free (attrs_pool, node);
842 /* Delete content of register with number REGNO in dataflow set SET. */
845 var_regno_delete (dataflow_set *set, int regno)
847 attrs *reg = &set->regs[regno];
850 for (node = *reg; node; node = next)
853 delete_variable_part (set, node->loc, node->decl, node->offset);
854 pool_free (attrs_pool, node);
859 /* Delete and set the location part of variable MEM_EXPR (LOC)
860 in dataflow set SET to LOC.
861 Adjust the address first if it is stack pointer based. */
864 var_mem_delete_and_set (dataflow_set *set, rtx loc)
866 tree decl = MEM_EXPR (loc);
867 HOST_WIDE_INT offset = MEM_OFFSET (loc) ? INTVAL (MEM_OFFSET (loc)) : 0;
869 set_variable_part (set, loc, decl, offset);
872 /* Delete the location part LOC from dataflow set SET.
873 Adjust the address first if it is stack pointer based. */
876 var_mem_delete (dataflow_set *set, rtx loc)
878 tree decl = MEM_EXPR (loc);
879 HOST_WIDE_INT offset = MEM_OFFSET (loc) ? INTVAL (MEM_OFFSET (loc)) : 0;
881 delete_variable_part (set, loc, decl, offset);
884 /* Initialize dataflow set SET to be empty.
885 VARS_SIZE is the initial size of hash table VARS. */
888 dataflow_set_init (dataflow_set *set, int vars_size)
890 init_attrs_list_set (set->regs);
891 set->vars = htab_create (vars_size, variable_htab_hash, variable_htab_eq,
893 set->stack_adjust = 0;
896 /* Delete the contents of dataflow set SET. */
899 dataflow_set_clear (dataflow_set *set)
903 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
904 attrs_list_clear (&set->regs[i]);
906 vars_clear (set->vars);
909 /* Copy the contents of dataflow set SRC to DST. */
912 dataflow_set_copy (dataflow_set *dst, dataflow_set *src)
916 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
917 attrs_list_copy (&dst->regs[i], src->regs[i]);
919 vars_copy (dst->vars, src->vars);
920 dst->stack_adjust = src->stack_adjust;
923 /* Information for merging lists of locations for a given offset of variable.
925 struct variable_union_info
927 /* Node of the location chain. */
930 /* The sum of positions in the input chains. */
933 /* The position in the chains of SRC and DST dataflow sets. */
938 /* Compare function for qsort, order the structures by POS element. */
941 variable_union_info_cmp_pos (const void *n1, const void *n2)
943 const struct variable_union_info *i1 = n1;
944 const struct variable_union_info *i2 = n2;
946 if (i1->pos != i2->pos)
947 return i1->pos - i2->pos;
949 return (i1->pos_dst - i2->pos_dst);
952 /* Compute union of location parts of variable *SLOT and the same variable
953 from hash table DATA. Compute "sorted" union of the location chains
954 for common offsets, i.e. the locations of a variable part are sorted by
955 a priority where the priority is the sum of the positions in the 2 chains
956 (if a location is only in one list the position in the second list is
957 defined to be larger than the length of the chains).
958 When we are updating the location parts the newest location is in the
959 beginning of the chain, so when we do the described "sorted" union
960 we keep the newest locations in the beginning. */
963 variable_union (void **slot, void *data)
965 variable src, dst, *dstp;
966 dataflow_set *set = (dataflow_set *) data;
969 src = *(variable *) slot;
970 dstp = (variable *) htab_find_slot_with_hash (set->vars, src->decl,
971 VARIABLE_HASH_VAL (src->decl),
975 *dstp = dst = pool_alloc (var_pool);
976 dst->decl = src->decl;
977 dst->n_var_parts = 0;
982 #ifdef ENABLE_CHECKING
983 if (src->n_var_parts == 0)
987 /* Count the number of location parts, result is K. */
988 for (i = 0, j = 0, k = 0;
989 i < src->n_var_parts && j < dst->n_var_parts; k++)
991 if (src->var_part[i].offset == dst->var_part[j].offset)
996 else if (src->var_part[i].offset < dst->var_part[j].offset)
1001 if (i < src->n_var_parts)
1002 k += src->n_var_parts - i;
1003 if (j < dst->n_var_parts)
1004 k += dst->n_var_parts - j;
1005 #ifdef ENABLE_CHECKING
1006 /* We track only variables whose size is <= MAX_VAR_PARTS bytes
1007 thus there are at most MAX_VAR_PARTS different offsets. */
1008 if (k > MAX_VAR_PARTS)
1012 i = src->n_var_parts - 1;
1013 j = dst->n_var_parts - 1;
1014 dst->n_var_parts = k;
1016 for (k--; k >= 0; k--)
1018 location_chain node;
1020 if (i >= 0 && j >= 0
1021 && src->var_part[i].offset == dst->var_part[j].offset)
1023 /* Compute the "sorted" union of the chains, i.e. the locations which
1024 are in both chains go first, they are sorted by the sum of
1025 positions in the chains. */
1028 struct variable_union_info *vui;
1031 for (node = src->var_part[i].loc_chain; node; node = node->next)
1034 for (node = dst->var_part[j].loc_chain; node; node = node->next)
1036 vui = xcalloc (src_l + dst_l, sizeof (struct variable_union_info));
1038 /* Fill in the locations from DST. */
1039 for (node = dst->var_part[j].loc_chain, jj = 0; node;
1040 node = node->next, jj++)
1043 vui[jj].pos_dst = jj;
1045 /* Value larger than a sum of 2 valid positions. */
1046 vui[jj].pos_src = src_l + dst_l;
1049 /* Fill in the locations from SRC. */
1051 for (node = src->var_part[i].loc_chain, ii = 0; node;
1052 node = node->next, ii++)
1054 /* Find location from NODE. */
1055 for (jj = 0; jj < dst_l; jj++)
1057 if ((GET_CODE (vui[jj].lc->loc) == REG
1058 && GET_CODE (node->loc) == REG
1059 && REGNO (vui[jj].lc->loc) == REGNO (node->loc))
1060 || rtx_equal_p (vui[jj].lc->loc, node->loc))
1062 vui[jj].pos_src = ii;
1066 if (jj >= dst_l) /* The location has not been found. */
1068 location_chain new_node;
1070 /* Copy the location from SRC. */
1071 new_node = pool_alloc (loc_chain_pool);
1072 new_node->loc = node->loc;
1073 vui[n].lc = new_node;
1074 vui[n].pos_src = ii;
1075 vui[n].pos_dst = src_l + dst_l;
1080 for (ii = 0; ii < src_l + dst_l; ii++)
1081 vui[ii].pos = vui[ii].pos_src + vui[ii].pos_dst;
1083 qsort (vui, n, sizeof (struct variable_union_info),
1084 variable_union_info_cmp_pos);
1086 /* Reconnect the nodes in sorted order. */
1087 for (ii = 1; ii < n; ii++)
1088 vui[ii - 1].lc->next = vui[ii].lc;
1089 vui[n - 1].lc->next = NULL;
1091 dst->var_part[k].loc_chain = vui[0].lc;
1092 dst->var_part[k].offset = dst->var_part[j].offset;
1098 else if ((i >= 0 && j >= 0
1099 && src->var_part[i].offset < dst->var_part[j].offset)
1102 dst->var_part[k] = dst->var_part[j];
1105 else if ((i >= 0 && j >= 0
1106 && src->var_part[i].offset > dst->var_part[j].offset)
1109 location_chain *nextp;
1111 /* Copy the chain from SRC. */
1112 nextp = &dst->var_part[k].loc_chain;
1113 for (node = src->var_part[i].loc_chain; node; node = node->next)
1115 location_chain new_lc;
1117 new_lc = pool_alloc (loc_chain_pool);
1118 new_lc->next = NULL;
1119 new_lc->loc = node->loc;
1122 nextp = &new_lc->next;
1125 dst->var_part[k].offset = src->var_part[i].offset;
1129 /* We are at the basic block boundary when computing union
1130 so set the CUR_LOC to be the first element of the chain. */
1131 if (dst->var_part[k].loc_chain)
1132 dst->var_part[k].cur_loc = dst->var_part[k].loc_chain->loc;
1134 dst->var_part[k].cur_loc = NULL;
1137 /* Continue traversing the hash table. */
1141 /* Compute union of dataflow sets SRC and DST and store it to DST. */
1144 dataflow_set_union (dataflow_set *dst, dataflow_set *src)
1148 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1149 attrs_list_union (&dst->regs[i], src->regs[i]);
1151 htab_traverse (src->vars, variable_union, dst);
1154 /* Flag whether two dataflow sets being compared contain different data. */
1156 dataflow_set_different_value;
1159 variable_part_different_p (variable_part *vp1, variable_part *vp2)
1161 location_chain lc1, lc2;
1163 for (lc1 = vp1->loc_chain; lc1; lc1 = lc1->next)
1165 for (lc2 = vp2->loc_chain; lc2; lc2 = lc2->next)
1167 if (GET_CODE (lc1->loc) == REG && GET_CODE (lc2->loc) == REG)
1169 if (REGNO (lc1->loc) == REGNO (lc2->loc))
1172 if (rtx_equal_p (lc1->loc, lc2->loc))
1181 /* Return true if variables VAR1 and VAR2 are different (only the first
1182 location in the list of locations is checked for each offset,
1183 i.e. when true is returned a note should be emitted). */
1186 variable_different_p (variable var1, variable var2)
1190 if (var1->n_var_parts != var2->n_var_parts)
1193 for (i = 0; i < var1->n_var_parts; i++)
1195 if (var1->var_part[i].offset != var2->var_part[i].offset)
1197 if (variable_part_different_p (&var1->var_part[i], &var2->var_part[i]))
1199 if (variable_part_different_p (&var2->var_part[i], &var1->var_part[i]))
1205 /* Compare variable *SLOT with the same variable in hash table DATA
1206 and set DATAFLOW_SET_DIFFERENT_VALUE if they are different. */
1209 dataflow_set_different_1 (void **slot, void *data)
1211 htab_t htab = (htab_t) data;
1212 variable var1, var2;
1214 var1 = *(variable *) slot;
1215 var2 = (variable) htab_find_with_hash (htab, var1->decl,
1216 VARIABLE_HASH_VAL (var1->decl));
1219 dataflow_set_different_value = true;
1221 /* Stop traversing the hash table. */
1225 if (variable_different_p (var1, var2))
1227 dataflow_set_different_value = true;
1229 /* Stop traversing the hash table. */
1233 /* Continue traversing the hash table. */
1237 /* Compare variable *SLOT with the same variable in hash table DATA
1238 and set DATAFLOW_SET_DIFFERENT_VALUE if they are different. */
1241 dataflow_set_different_2 (void **slot, void *data)
1243 htab_t htab = (htab_t) data;
1244 variable var1, var2;
1246 var1 = *(variable *) slot;
1247 var2 = (variable) htab_find_with_hash (htab, var1->decl,
1248 VARIABLE_HASH_VAL (var1->decl));
1251 dataflow_set_different_value = true;
1253 /* Stop traversing the hash table. */
1257 #ifdef ENABLE_CHECKING
1258 /* If both variables are defined they have been already checked for
1260 if (variable_different_p (var1, var2))
1264 /* Continue traversing the hash table. */
1268 /* Return true if dataflow sets OLD_SET and NEW_SET differ. */
1271 dataflow_set_different (dataflow_set *old_set, dataflow_set *new_set)
1273 dataflow_set_different_value = false;
1275 htab_traverse (old_set->vars, dataflow_set_different_1, new_set->vars);
1276 if (!dataflow_set_different_value)
1278 /* We have compared the variables which are in both hash tables
1279 so now only check whether there are some variables in NEW_SET->VARS
1280 which are not in OLD_SET->VARS. */
1281 htab_traverse (new_set->vars, dataflow_set_different_2, old_set->vars);
1283 return dataflow_set_different_value;
1286 /* Free the contents of dataflow set SET. */
1289 dataflow_set_destroy (dataflow_set *set)
1293 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1294 attrs_list_clear (&set->regs[i]);
1296 htab_delete (set->vars);
1300 /* Return true if RTL X contains a SYMBOL_REF. */
1303 contains_symbol_ref (rtx x)
1312 code = GET_CODE (x);
1313 if (code == SYMBOL_REF)
1316 fmt = GET_RTX_FORMAT (code);
1317 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1321 if (contains_symbol_ref (XEXP (x, i)))
1324 else if (fmt[i] == 'E')
1327 for (j = 0; j < XVECLEN (x, i); j++)
1328 if (contains_symbol_ref (XVECEXP (x, i, j)))
1336 /* Shall EXPR be tracked? */
1339 track_expr_p (tree expr)
1343 /* If EXPR is not a parameter or a variable do not track it. */
1344 if (TREE_CODE (expr) != VAR_DECL && TREE_CODE (expr) != PARM_DECL)
1347 /* It also must have a name... */
1348 if (!DECL_NAME (expr))
1351 /* ... and a RTL assigned to it. */
1352 decl_rtl = DECL_RTL_IF_SET (expr);
1356 /* Do not track EXPR if it should be ignored for debugging purposes. */
1357 if (DECL_IGNORED_P (expr))
1360 /* Do not track global variables until we are able to emit correct location
1362 if (TREE_STATIC (expr))
1365 /* When the EXPR is a DECL for alias of some variable (see example)
1366 the TREE_STATIC flag is not used. Disable tracking all DECLs whose
1367 DECL_RTL contains SYMBOL_REF.
1370 extern char **_dl_argv_internal __attribute__ ((alias ("_dl_argv")));
1373 if (GET_CODE (decl_rtl) == MEM
1374 && contains_symbol_ref (XEXP (decl_rtl, 0)))
1377 /* If RTX is a memory it should not be very large (because it would be
1378 an array or struct). */
1379 if (GET_CODE (decl_rtl) == MEM)
1381 /* Do not track structures and arrays. */
1382 if (GET_MODE (decl_rtl) == BLKmode)
1384 if (MEM_SIZE (decl_rtl)
1385 && INTVAL (MEM_SIZE (decl_rtl)) > MAX_VAR_PARTS)
1392 /* Count uses (register and memory references) LOC which will be tracked.
1393 INSN is instruction which the LOC is part of. */
1396 count_uses (rtx *loc, void *insn)
1398 basic_block bb = BLOCK_FOR_INSN ((rtx) insn);
1400 if (GET_CODE (*loc) == REG)
1402 #ifdef ENABLE_CHECKING
1403 if (REGNO (*loc) >= FIRST_PSEUDO_REGISTER)
1408 else if (GET_CODE (*loc) == MEM
1410 && track_expr_p (MEM_EXPR (*loc)))
1418 /* Helper function for finding all uses of REG/MEM in X in insn INSN. */
1421 count_uses_1 (rtx *x, void *insn)
1423 for_each_rtx (x, count_uses, insn);
1426 /* Count stores (register and memory references) LOC which will be tracked.
1427 INSN is instruction which the LOC is part of. */
1430 count_stores (rtx loc, rtx expr ATTRIBUTE_UNUSED, void *insn)
1432 count_uses (&loc, insn);
1435 /* Add uses (register and memory references) LOC which will be tracked
1436 to VTI (bb)->mos. INSN is instruction which the LOC is part of. */
1439 add_uses (rtx *loc, void *insn)
1441 if (GET_CODE (*loc) == REG)
1443 basic_block bb = BLOCK_FOR_INSN ((rtx) insn);
1444 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
1446 mo->type = ((REG_EXPR (*loc) && track_expr_p (REG_EXPR (*loc)))
1447 ? MO_USE : MO_USE_NO_VAR);
1449 mo->insn = (rtx) insn;
1451 else if (GET_CODE (*loc) == MEM
1453 && track_expr_p (MEM_EXPR (*loc)))
1455 basic_block bb = BLOCK_FOR_INSN ((rtx) insn);
1456 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
1460 mo->insn = (rtx) insn;
1466 /* Helper function for finding all uses of REG/MEM in X in insn INSN. */
1469 add_uses_1 (rtx *x, void *insn)
1471 for_each_rtx (x, add_uses, insn);
1474 /* Add stores (register and memory references) LOC which will be tracked
1475 to VTI (bb)->mos. EXPR is the RTL expression containing the store.
1476 INSN is instruction which the LOC is part of. */
1479 add_stores (rtx loc, rtx expr, void *insn)
1481 if (GET_CODE (loc) == REG)
1483 basic_block bb = BLOCK_FOR_INSN ((rtx) insn);
1484 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
1486 mo->type = ((GET_CODE (expr) != CLOBBER && REG_EXPR (loc)
1487 && track_expr_p (REG_EXPR (loc)))
1488 ? MO_SET : MO_CLOBBER);
1490 mo->insn = (rtx) insn;
1492 else if (GET_CODE (loc) == MEM
1494 && track_expr_p (MEM_EXPR (loc)))
1496 basic_block bb = BLOCK_FOR_INSN ((rtx) insn);
1497 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
1499 mo->type = GET_CODE (expr) == CLOBBER ? MO_CLOBBER : MO_SET;
1501 mo->insn = (rtx) insn;
1505 /* Compute the changes of variable locations in the basic block BB. */
1508 compute_bb_dataflow (basic_block bb)
1512 dataflow_set old_out;
1513 dataflow_set *in = &VTI (bb)->in;
1514 dataflow_set *out = &VTI (bb)->out;
1516 dataflow_set_init (&old_out, htab_elements (VTI (bb)->out.vars) + 3);
1517 dataflow_set_copy (&old_out, out);
1518 dataflow_set_copy (out, in);
1520 n = VTI (bb)->n_mos;
1521 for (i = 0; i < n; i++)
1523 switch (VTI (bb)->mos[i].type)
1526 for (r = 0; r < FIRST_PSEUDO_REGISTER; r++)
1527 if (TEST_HARD_REG_BIT (call_used_reg_set, r))
1528 var_regno_delete (out, r);
1534 rtx loc = VTI (bb)->mos[i].u.loc;
1536 if (GET_CODE (loc) == REG)
1537 var_reg_delete_and_set (out, loc);
1538 else if (GET_CODE (loc) == MEM)
1539 var_mem_delete_and_set (out, loc);
1546 rtx loc = VTI (bb)->mos[i].u.loc;
1548 if (GET_CODE (loc) == REG)
1549 var_reg_delete (out, loc);
1550 else if (GET_CODE (loc) == MEM)
1551 var_mem_delete (out, loc);
1559 out->stack_adjust += VTI (bb)->mos[i].u.adjust;
1560 base = gen_rtx_MEM (Pmode,
1561 gen_rtx_PLUS (Pmode, stack_pointer_rtx,
1562 GEN_INT (out->stack_adjust)));
1563 set_frame_base_location (out, base);
1569 changed = dataflow_set_different (&old_out, out);
1570 dataflow_set_destroy (&old_out);
1574 /* Find the locations of variables in the whole function. */
1577 vt_find_locations (void)
1579 fibheap_t worklist, pending, fibheap_swap;
1580 sbitmap visited, in_worklist, in_pending, sbitmap_swap;
1587 /* Compute reverse completion order of depth first search of the CFG
1588 so that the data-flow runs faster. */
1589 rc_order = (int *) xmalloc (n_basic_blocks * sizeof (int));
1590 bb_order = (int *) xmalloc (last_basic_block * sizeof (int));
1591 flow_depth_first_order_compute (NULL, rc_order);
1592 for (i = 0; i < n_basic_blocks; i++)
1593 bb_order[rc_order[i]] = i;
1596 worklist = fibheap_new ();
1597 pending = fibheap_new ();
1598 visited = sbitmap_alloc (last_basic_block);
1599 in_worklist = sbitmap_alloc (last_basic_block);
1600 in_pending = sbitmap_alloc (last_basic_block);
1601 sbitmap_zero (in_worklist);
1602 sbitmap_zero (in_pending);
1606 fibheap_insert (pending, bb_order[bb->index], bb);
1607 SET_BIT (in_pending, bb->index);
1610 while (!fibheap_empty (pending))
1612 fibheap_swap = pending;
1614 worklist = fibheap_swap;
1615 sbitmap_swap = in_pending;
1616 in_pending = in_worklist;
1617 in_worklist = sbitmap_swap;
1619 sbitmap_zero (visited);
1621 while (!fibheap_empty (worklist))
1623 bb = fibheap_extract_min (worklist);
1624 RESET_BIT (in_worklist, bb->index);
1625 if (!TEST_BIT (visited, bb->index))
1629 SET_BIT (visited, bb->index);
1631 /* Calculate the IN set as union of predecessor OUT sets. */
1632 dataflow_set_clear (&VTI (bb)->in);
1633 for (e = bb->pred; e; e = e->pred_next)
1635 dataflow_set_union (&VTI (bb)->in, &VTI (e->src)->out);
1638 changed = compute_bb_dataflow (bb);
1641 for (e = bb->succ; e; e = e->succ_next)
1643 if (e->dest == EXIT_BLOCK_PTR)
1649 if (TEST_BIT (visited, e->dest->index))
1651 if (!TEST_BIT (in_pending, e->dest->index))
1653 /* Send E->DEST to next round. */
1654 SET_BIT (in_pending, e->dest->index);
1655 fibheap_insert (pending,
1656 bb_order[e->dest->index],
1660 else if (!TEST_BIT (in_worklist, e->dest->index))
1662 /* Add E->DEST to current round. */
1663 SET_BIT (in_worklist, e->dest->index);
1664 fibheap_insert (worklist, bb_order[e->dest->index],
1674 fibheap_delete (worklist);
1675 fibheap_delete (pending);
1676 sbitmap_free (visited);
1677 sbitmap_free (in_worklist);
1678 sbitmap_free (in_pending);
1681 /* Print the content of the LIST to dump file. */
1684 dump_attrs_list (attrs list)
1686 for (; list; list = list->next)
1688 print_mem_expr (dump_file, list->decl);
1689 fprintf (dump_file, "+");
1690 fprintf (dump_file, HOST_WIDE_INT_PRINT_DEC, list->offset);
1692 fprintf (dump_file, "\n");
1695 /* Print the information about variable *SLOT to dump file. */
1698 dump_variable (void **slot, void *data ATTRIBUTE_UNUSED)
1700 variable var = *(variable *) slot;
1702 location_chain node;
1704 fprintf (dump_file, " name: %s\n",
1705 IDENTIFIER_POINTER (DECL_NAME (var->decl)));
1706 for (i = 0; i < var->n_var_parts; i++)
1708 fprintf (dump_file, " offset %ld\n",
1709 (long) var->var_part[i].offset);
1710 for (node = var->var_part[i].loc_chain; node; node = node->next)
1712 fprintf (dump_file, " ");
1713 print_rtl_single (dump_file, node->loc);
1717 /* Continue traversing the hash table. */
1721 /* Print the information about variables from hash table VARS to dump file. */
1724 dump_vars (htab_t vars)
1726 if (htab_elements (vars) > 0)
1728 fprintf (dump_file, "Variables:\n");
1729 htab_traverse (vars, dump_variable, NULL);
1733 /* Print the dataflow set SET to dump file. */
1736 dump_dataflow_set (dataflow_set *set)
1740 fprintf (dump_file, "Stack adjustment: ");
1741 fprintf (dump_file, HOST_WIDE_INT_PRINT_DEC, set->stack_adjust);
1742 fprintf (dump_file, "\n");
1743 for (i = 1; i < FIRST_PSEUDO_REGISTER; i++)
1747 fprintf (dump_file, "Reg %d:", i);
1748 dump_attrs_list (set->regs[i]);
1751 dump_vars (set->vars);
1752 fprintf (dump_file, "\n");
1755 /* Print the IN and OUT sets for each basic block to dump file. */
1758 dump_dataflow_sets (void)
1764 fprintf (dump_file, "\nBasic block %d:\n", bb->index);
1765 fprintf (dump_file, "IN:\n");
1766 dump_dataflow_set (&VTI (bb)->in);
1767 fprintf (dump_file, "OUT:\n");
1768 dump_dataflow_set (&VTI (bb)->out);
1772 /* Add variable VAR to the hash table of changed variables and
1773 if it has no locations delete it from hash table HTAB. */
1776 variable_was_changed (variable var, htab_t htab)
1778 hashval_t hash = VARIABLE_HASH_VAL (var->decl);
1784 slot = (variable *) htab_find_slot_with_hash (changed_variables,
1785 var->decl, hash, INSERT);
1787 if (htab && var->n_var_parts == 0)
1792 empty_var = pool_alloc (var_pool);
1793 empty_var->decl = var->decl;
1794 empty_var->n_var_parts = 0;
1797 old = htab_find_slot_with_hash (htab, var->decl, hash,
1800 htab_clear_slot (htab, old);
1809 #ifdef ENABLE_CHECKING
1813 if (var->n_var_parts == 0)
1815 void **slot = htab_find_slot_with_hash (htab, var->decl, hash,
1818 htab_clear_slot (htab, slot);
1823 /* Set the location of frame_base_decl to LOC in dataflow set SET. This
1824 function expects that
1825 frame_base_decl has already one location for offset 0 in the variable table.
1829 set_frame_base_location (dataflow_set *set, rtx loc)
1833 var = htab_find_with_hash (set->vars, frame_base_decl,
1834 VARIABLE_HASH_VAL (frame_base_decl));
1835 #ifdef ENABLE_CHECKING
1838 if (var->n_var_parts != 1)
1840 if (var->var_part[0].offset != 0)
1842 if (!var->var_part[0].loc_chain)
1846 var->var_part[0].loc_chain->loc = loc;
1847 variable_was_changed (var, set->vars);
1850 /* Set the part of variable's location in the dataflow set SET. The variable
1851 part is specified by variable's declaration DECL and offset OFFSET and the
1852 part's location by LOC. */
1855 set_variable_part (dataflow_set *set, rtx loc, tree decl, HOST_WIDE_INT offset)
1858 location_chain node, next;
1859 location_chain *nextp;
1863 slot = htab_find_slot_with_hash (set->vars, decl,
1864 VARIABLE_HASH_VAL (decl), INSERT);
1867 /* Create new variable information. */
1868 var = pool_alloc (var_pool);
1870 var->n_var_parts = 1;
1871 var->var_part[0].offset = offset;
1872 var->var_part[0].loc_chain = NULL;
1873 var->var_part[0].cur_loc = NULL;
1879 var = (variable) *slot;
1881 /* Find the location part. */
1883 high = var->n_var_parts;
1886 pos = (low + high) / 2;
1887 if (var->var_part[pos].offset < offset)
1894 if (pos == var->n_var_parts || var->var_part[pos].offset != offset)
1896 /* We have not find the location part, new one will be created. */
1898 #ifdef ENABLE_CHECKING
1899 /* We track only variables whose size is <= MAX_VAR_PARTS bytes
1900 thus there are at most MAX_VAR_PARTS different offsets. */
1901 if (var->n_var_parts >= MAX_VAR_PARTS)
1905 /* We have to move the elements of array starting at index low to the
1907 for (high = var->n_var_parts; high > low; high--)
1908 var->var_part[high] = var->var_part[high - 1];
1911 var->var_part[pos].offset = offset;
1912 var->var_part[pos].loc_chain = NULL;
1913 var->var_part[pos].cur_loc = NULL;
1917 /* Delete the location from list. */
1918 nextp = &var->var_part[pos].loc_chain;
1919 for (node = var->var_part[pos].loc_chain; node; node = next)
1922 if ((GET_CODE (node->loc) == REG && GET_CODE (loc) == REG
1923 && REGNO (node->loc) == REGNO (loc))
1924 || rtx_equal_p (node->loc, loc))
1926 pool_free (loc_chain_pool, node);
1931 nextp = &node->next;
1934 /* Add the location to the beginning. */
1935 node = pool_alloc (loc_chain_pool);
1937 node->next = var->var_part[pos].loc_chain;
1938 var->var_part[pos].loc_chain = node;
1940 /* If no location was emitted do so. */
1941 if (var->var_part[pos].cur_loc == NULL)
1943 var->var_part[pos].cur_loc = loc;
1944 variable_was_changed (var, set->vars);
1948 /* Delete the part of variable's location from dataflow set SET. The variable
1949 part is specified by variable's declaration DECL and offset OFFSET and the
1950 part's location by LOC. */
1953 delete_variable_part (dataflow_set *set, rtx loc, tree decl,
1954 HOST_WIDE_INT offset)
1959 slot = htab_find_slot_with_hash (set->vars, decl, VARIABLE_HASH_VAL (decl),
1963 variable var = (variable) *slot;
1965 /* Find the location part. */
1967 high = var->n_var_parts;
1970 pos = (low + high) / 2;
1971 if (var->var_part[pos].offset < offset)
1978 if (pos < var->n_var_parts && var->var_part[pos].offset == offset)
1980 location_chain node, next;
1981 location_chain *nextp;
1984 /* Delete the location part. */
1985 nextp = &var->var_part[pos].loc_chain;
1986 for (node = *nextp; node; node = next)
1989 if ((GET_CODE (node->loc) == REG && GET_CODE (loc) == REG
1990 && REGNO (node->loc) == REGNO (loc))
1991 || rtx_equal_p (node->loc, loc))
1993 pool_free (loc_chain_pool, node);
1998 nextp = &node->next;
2001 /* If we have deleted the location which was last emitted
2002 we have to emit new location so add the variable to set
2003 of changed variables. */
2004 if (var->var_part[pos].cur_loc
2005 && ((GET_CODE (loc) == REG
2006 && GET_CODE (var->var_part[pos].cur_loc) == REG
2007 && REGNO (loc) == REGNO (var->var_part[pos].cur_loc))
2008 || rtx_equal_p (loc, var->var_part[pos].cur_loc)))
2011 if (var->var_part[pos].loc_chain)
2012 var->var_part[pos].cur_loc = var->var_part[pos].loc_chain->loc;
2017 if (var->var_part[pos].loc_chain == NULL)
2020 while (pos < var->n_var_parts)
2022 var->var_part[pos] = var->var_part[pos + 1];
2027 variable_was_changed (var, set->vars);
2032 /* Emit the NOTE_INSN_VAR_LOCATION for variable *VARP. DATA contains
2033 additional parameters: WHERE specifies whether the note shall be emitted
2034 before of after instruction INSN. */
2037 emit_note_insn_var_location (void **varp, void *data)
2039 variable var = *(variable *) varp;
2040 rtx insn = ((emit_note_data *)data)->insn;
2041 enum emit_note_where where = ((emit_note_data *)data)->where;
2045 HOST_WIDE_INT last_limit;
2046 tree type_size_unit;
2048 #ifdef ENABLE_CHECKING
2055 for (i = 0; i < var->n_var_parts; i++)
2057 if (last_limit < var->var_part[i].offset)
2063 = (var->var_part[i].offset
2064 + GET_MODE_SIZE (GET_MODE (var->var_part[i].loc_chain->loc)));
2066 type_size_unit = TYPE_SIZE_UNIT (TREE_TYPE (var->decl));
2067 if ((unsigned HOST_WIDE_INT) last_limit < TREE_INT_CST_LOW (type_size_unit))
2070 if (where == EMIT_NOTE_AFTER_INSN)
2071 note = emit_note_after (NOTE_INSN_VAR_LOCATION, insn);
2073 note = emit_note_before (NOTE_INSN_VAR_LOCATION, insn);
2077 NOTE_VAR_LOCATION (note) = gen_rtx_VAR_LOCATION (VOIDmode, var->decl,
2080 else if (var->n_var_parts == 1)
2083 = gen_rtx_EXPR_LIST (VOIDmode,
2084 var->var_part[0].loc_chain->loc,
2085 GEN_INT (var->var_part[0].offset));
2087 NOTE_VAR_LOCATION (note) = gen_rtx_VAR_LOCATION (VOIDmode, var->decl,
2090 else if (var->n_var_parts)
2092 rtx argp[MAX_VAR_PARTS];
2095 for (i = 0; i < var->n_var_parts; i++)
2096 argp[i] = gen_rtx_EXPR_LIST (VOIDmode, var->var_part[i].loc_chain->loc,
2097 GEN_INT (var->var_part[i].offset));
2098 parallel = gen_rtx_PARALLEL (VOIDmode,
2099 gen_rtvec_v (var->n_var_parts, argp));
2100 NOTE_VAR_LOCATION (note) = gen_rtx_VAR_LOCATION (VOIDmode, var->decl,
2104 htab_clear_slot (changed_variables, varp);
2106 /* When there are no location parts the variable has been already
2107 removed from hash table and a new empty variable was created.
2108 Free the empty variable. */
2109 if (var->n_var_parts == 0)
2111 pool_free (var_pool, var);
2114 /* Continue traversing the hash table. */
2118 /* Emit NOTE_INSN_VAR_LOCATION note for each variable from a chain
2119 CHANGED_VARIABLES and delete this chain. WHERE specifies whether the notes
2120 shall be emitted before of after instruction INSN. */
2123 emit_notes_for_changes (rtx insn, enum emit_note_where where)
2125 emit_note_data data;
2129 htab_traverse (changed_variables, emit_note_insn_var_location, &data);
2132 /* Add variable *SLOT to the chain CHANGED_VARIABLES if it differs from the
2133 same variable in hash table DATA or is not there at all. */
2136 emit_notes_for_differences_1 (void **slot, void *data)
2138 htab_t new_vars = (htab_t) data;
2139 variable old_var, new_var;
2141 old_var = *(variable *) slot;
2142 new_var = (variable) htab_find_with_hash (new_vars, old_var->decl,
2143 VARIABLE_HASH_VAL (old_var->decl));
2147 /* Variable has disappeared. */
2150 empty_var = pool_alloc (var_pool);
2151 empty_var->decl = old_var->decl;
2152 empty_var->n_var_parts = 0;
2153 variable_was_changed (empty_var, NULL);
2155 else if (variable_different_p (old_var, new_var))
2157 variable_was_changed (new_var, NULL);
2160 /* Continue traversing the hash table. */
2164 /* Add variable *SLOT to the chain CHANGED_VARIABLES if it is not in hash
2168 emit_notes_for_differences_2 (void **slot, void *data)
2170 htab_t old_vars = (htab_t) data;
2171 variable old_var, new_var;
2173 new_var = *(variable *) slot;
2174 old_var = (variable) htab_find_with_hash (old_vars, new_var->decl,
2175 VARIABLE_HASH_VAL (new_var->decl));
2178 /* Variable has appeared. */
2179 variable_was_changed (new_var, NULL);
2182 /* Continue traversing the hash table. */
2186 /* Emit notes before INSN for differences between dataflow sets OLD_SET and
2190 emit_notes_for_differences (rtx insn, dataflow_set *old_set,
2191 dataflow_set *new_set)
2193 htab_traverse (old_set->vars, emit_notes_for_differences_1, new_set->vars);
2194 htab_traverse (new_set->vars, emit_notes_for_differences_2, old_set->vars);
2195 emit_notes_for_changes (insn, EMIT_NOTE_BEFORE_INSN);
2198 /* Emit the notes for changes of location parts in the basic block BB. */
2201 emit_notes_in_bb (basic_block bb)
2206 dataflow_set_init (&set, htab_elements (VTI (bb)->in.vars) + 3);
2207 dataflow_set_copy (&set, &VTI (bb)->in);
2209 for (i = 0; i < VTI (bb)->n_mos; i++)
2211 rtx insn = VTI (bb)->mos[i].insn;
2213 switch (VTI (bb)->mos[i].type)
2219 for (r = 0; r < FIRST_PSEUDO_REGISTER; r++)
2220 if (TEST_HARD_REG_BIT (call_used_reg_set, r))
2222 var_regno_delete (&set, r);
2224 emit_notes_for_changes (insn, EMIT_NOTE_AFTER_INSN);
2231 rtx loc = VTI (bb)->mos[i].u.loc;
2233 if (GET_CODE (loc) == REG)
2234 var_reg_delete_and_set (&set, loc);
2236 var_mem_delete_and_set (&set, loc);
2238 if (VTI (bb)->mos[i].type == MO_USE)
2239 emit_notes_for_changes (insn, EMIT_NOTE_BEFORE_INSN);
2241 emit_notes_for_changes (insn, EMIT_NOTE_AFTER_INSN);
2248 rtx loc = VTI (bb)->mos[i].u.loc;
2250 if (GET_CODE (loc) == REG)
2251 var_reg_delete (&set, loc);
2253 var_mem_delete (&set, loc);
2255 if (VTI (bb)->mos[i].type == MO_USE_NO_VAR)
2256 emit_notes_for_changes (insn, EMIT_NOTE_BEFORE_INSN);
2258 emit_notes_for_changes (insn, EMIT_NOTE_AFTER_INSN);
2266 set.stack_adjust += VTI (bb)->mos[i].u.adjust;
2267 base = gen_rtx_MEM (Pmode,
2268 gen_rtx_PLUS (Pmode, stack_pointer_rtx,
2269 GEN_INT (set.stack_adjust)));
2270 set_frame_base_location (&set, base);
2271 emit_notes_for_changes (insn, EMIT_NOTE_AFTER_INSN);
2276 dataflow_set_destroy (&set);
2279 /* Emit notes for the whole function. */
2282 vt_emit_notes (void)
2285 dataflow_set *last_out;
2288 #ifdef ENABLE_CHECKING
2289 if (htab_elements (changed_variables))
2293 /* Enable emitting notes by functions (mainly by set_variable_part and
2294 delete_variable_part). */
2297 dataflow_set_init (&empty, 7);
2302 /* Emit the notes for changes of variable locations between two
2303 subsequent basic blocks. */
2304 emit_notes_for_differences (BB_HEAD (bb), last_out, &VTI (bb)->in);
2306 /* Emit the notes for the changes in the basic block itself. */
2307 emit_notes_in_bb (bb);
2309 last_out = &VTI (bb)->out;
2311 dataflow_set_destroy (&empty);
2315 /* If there is a declaration and offset associated with register/memory RTL
2316 assign declaration to *DECLP and offset to *OFFSETP, and return true. */
2319 vt_get_decl_and_offset (rtx rtl, tree *declp, HOST_WIDE_INT *offsetp)
2321 if (GET_CODE (rtl) == REG)
2323 if (REG_ATTRS (rtl))
2325 *declp = REG_EXPR (rtl);
2326 *offsetp = REG_OFFSET (rtl);
2330 else if (GET_CODE (rtl) == MEM)
2332 if (MEM_ATTRS (rtl))
2334 *declp = MEM_EXPR (rtl);
2335 *offsetp = MEM_OFFSET (rtl) ? INTVAL (MEM_OFFSET (rtl)) : 0;
2342 /* Insert function parameters to IN and OUT sets of ENTRY_BLOCK. */
2345 vt_add_function_parameters (void)
2348 HOST_WIDE_INT stack_adjust = 0;
2350 if (!frame_pointer_needed)
2351 stack_adjust = prologue_stack_adjust ();
2353 for (parm = DECL_ARGUMENTS (current_function_decl);
2354 parm; parm = TREE_CHAIN (parm))
2356 rtx decl_rtl = DECL_RTL_IF_SET (parm);
2357 rtx incoming = DECL_INCOMING_RTL (parm);
2359 HOST_WIDE_INT offset;
2360 dataflow_set *in, *out;
2362 if (TREE_CODE (parm) != PARM_DECL)
2365 if (!DECL_NAME (parm))
2368 if (!decl_rtl || !incoming)
2371 if (GET_MODE (decl_rtl) == BLKmode || GET_MODE (incoming) == BLKmode)
2374 if (!vt_get_decl_and_offset (incoming, &decl, &offset))
2375 if (!vt_get_decl_and_offset (decl_rtl, &decl, &offset))
2381 #ifdef ENABLE_CHECKING
2386 incoming = eliminate_regs (incoming, 0, NULL_RTX);
2387 if (!frame_pointer_needed && GET_CODE (incoming) == MEM)
2388 incoming = adjust_stack_reference (incoming, -stack_adjust);
2389 in = &VTI (ENTRY_BLOCK_PTR)->in;
2390 out = &VTI (ENTRY_BLOCK_PTR)->out;
2392 if (GET_CODE (incoming) == REG)
2394 #ifdef ENABLE_CHECKING
2395 if (REGNO (incoming) >= FIRST_PSEUDO_REGISTER)
2398 attrs_list_insert (&in->regs[REGNO (incoming)],
2399 parm, offset, incoming);
2400 attrs_list_insert (&out->regs[REGNO (incoming)],
2401 parm, offset, incoming);
2402 set_variable_part (in, incoming, parm, offset);
2403 set_variable_part (out, incoming, parm, offset);
2405 else if (GET_CODE (incoming) == MEM)
2407 set_variable_part (in, incoming, parm, offset);
2408 set_variable_part (out, incoming, parm, offset);
2413 /* Allocate and initialize the data structures for variable tracking
2414 and parse the RTL to get the micro operations. */
2417 vt_initialize (void)
2421 alloc_aux_for_blocks (sizeof (struct variable_tracking_info_def));
2426 HOST_WIDE_INT pre, post;
2428 /* Count the number of micro operations. */
2429 VTI (bb)->n_mos = 0;
2430 for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb));
2431 insn = NEXT_INSN (insn))
2435 if (!frame_pointer_needed)
2437 insn_stack_adjust_offset_pre_post (insn, &pre, &post);
2443 note_uses (&PATTERN (insn), count_uses_1, insn);
2444 note_stores (PATTERN (insn), count_stores, insn);
2445 if (GET_CODE (insn) == CALL_INSN)
2450 /* Add the micro-operations to the array. */
2451 VTI (bb)->mos = xmalloc (VTI (bb)->n_mos
2452 * sizeof (struct micro_operation_def));
2453 VTI (bb)->n_mos = 0;
2454 for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb));
2455 insn = NEXT_INSN (insn))
2461 if (!frame_pointer_needed)
2463 insn_stack_adjust_offset_pre_post (insn, &pre, &post);
2466 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
2468 mo->type = MO_ADJUST;
2474 n1 = VTI (bb)->n_mos;
2475 note_uses (&PATTERN (insn), add_uses_1, insn);
2476 n2 = VTI (bb)->n_mos - 1;
2478 /* Order the MO_USEs to be before MO_USE_NO_VARs. */
2481 while (n1 < n2 && VTI (bb)->mos[n1].type == MO_USE)
2483 while (n1 < n2 && VTI (bb)->mos[n2].type == MO_USE_NO_VAR)
2489 sw = VTI (bb)->mos[n1];
2490 VTI (bb)->mos[n1] = VTI (bb)->mos[n2];
2491 VTI (bb)->mos[n2] = sw;
2495 if (GET_CODE (insn) == CALL_INSN)
2497 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
2503 n1 = VTI (bb)->n_mos;
2504 note_stores (PATTERN (insn), add_stores, insn);
2505 n2 = VTI (bb)->n_mos - 1;
2507 /* Order the MO_SETs to be before MO_CLOBBERs. */
2510 while (n1 < n2 && VTI (bb)->mos[n1].type == MO_SET)
2512 while (n1 < n2 && VTI (bb)->mos[n2].type == MO_CLOBBER)
2518 sw = VTI (bb)->mos[n1];
2519 VTI (bb)->mos[n1] = VTI (bb)->mos[n2];
2520 VTI (bb)->mos[n2] = sw;
2524 if (!frame_pointer_needed && post)
2526 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
2528 mo->type = MO_ADJUST;
2529 mo->u.adjust = post;
2536 /* Init the IN and OUT sets. */
2539 VTI (bb)->visited = false;
2540 dataflow_set_init (&VTI (bb)->in, 7);
2541 dataflow_set_init (&VTI (bb)->out, 7);
2544 attrs_pool = create_alloc_pool ("attrs_def pool",
2545 sizeof (struct attrs_def), 1024);
2546 var_pool = create_alloc_pool ("variable_def pool",
2547 sizeof (struct variable_def), 64);
2548 loc_chain_pool = create_alloc_pool ("location_chain_def pool",
2549 sizeof (struct location_chain_def),
2551 changed_variables = htab_create (10, variable_htab_hash, variable_htab_eq,
2553 vt_add_function_parameters ();
2555 if (!frame_pointer_needed)
2559 /* Create fake variable for tracking stack pointer changes. */
2560 frame_base_decl = make_node (VAR_DECL);
2561 DECL_NAME (frame_base_decl) = get_identifier ("___frame_base_decl");
2562 TREE_TYPE (frame_base_decl) = char_type_node;
2563 DECL_ARTIFICIAL (frame_base_decl) = 1;
2565 /* Set its initial "location". */
2566 base = gen_rtx_MEM (Pmode, stack_pointer_rtx);
2567 set_variable_part (&VTI (ENTRY_BLOCK_PTR)->in, base, frame_base_decl, 0);
2568 set_variable_part (&VTI (ENTRY_BLOCK_PTR)->out, base, frame_base_decl, 0);
2572 frame_base_decl = NULL;
2576 /* Free the data structures needed for variable tracking. */
2585 free (VTI (bb)->mos);
2590 dataflow_set_destroy (&VTI (bb)->in);
2591 dataflow_set_destroy (&VTI (bb)->out);
2593 free_aux_for_blocks ();
2594 free_alloc_pool (attrs_pool);
2595 free_alloc_pool (var_pool);
2596 free_alloc_pool (loc_chain_pool);
2597 htab_delete (changed_variables);
2600 /* The entry point to variable tracking pass. */
2603 variable_tracking_main (void)
2605 if (n_basic_blocks > 500 && n_edges / n_basic_blocks >= 20)
2608 mark_dfs_back_edges ();
2610 if (!frame_pointer_needed)
2612 if (!vt_stack_adjustments ())
2619 vt_find_locations ();
2624 dump_dataflow_sets ();
2625 dump_flow_info (dump_file);