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 /* 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) ((size_t) (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 GTY(()) tree frame_base_decl;
270 /* Local function prototypes. */
271 static void stack_adjust_offset_pre_post (rtx, HOST_WIDE_INT *,
273 static void insn_stack_adjust_offset_pre_post (rtx, HOST_WIDE_INT *,
275 static void bb_stack_adjust_offset (basic_block);
276 static HOST_WIDE_INT prologue_stack_adjust (void);
277 static bool vt_stack_adjustments (void);
278 static rtx adjust_stack_reference (rtx, HOST_WIDE_INT);
279 static hashval_t variable_htab_hash (const void *);
280 static int variable_htab_eq (const void *, const void *);
281 static void variable_htab_free (void *);
283 static void init_attrs_list_set (attrs *);
284 static void attrs_list_clear (attrs *);
285 static attrs attrs_list_member (attrs, tree, HOST_WIDE_INT);
286 static void attrs_list_insert (attrs *, tree, HOST_WIDE_INT, rtx);
287 static void attrs_list_copy (attrs *, attrs);
288 static void attrs_list_union (attrs *, attrs);
290 static void vars_clear (htab_t);
291 static variable unshare_variable (dataflow_set *set, variable var);
292 static int vars_copy_1 (void **, void *);
293 static void vars_copy (htab_t, htab_t);
294 static void var_reg_delete_and_set (dataflow_set *, rtx);
295 static void var_reg_delete (dataflow_set *, rtx);
296 static void var_regno_delete (dataflow_set *, int);
297 static void var_mem_delete_and_set (dataflow_set *, rtx);
298 static void var_mem_delete (dataflow_set *, rtx);
300 static void dataflow_set_init (dataflow_set *, int);
301 static void dataflow_set_clear (dataflow_set *);
302 static void dataflow_set_copy (dataflow_set *, dataflow_set *);
303 static int variable_union_info_cmp_pos (const void *, const void *);
304 static int variable_union (void **, void *);
305 static void dataflow_set_union (dataflow_set *, dataflow_set *);
306 static bool variable_part_different_p (variable_part *, variable_part *);
307 static bool variable_different_p (variable, variable);
308 static int dataflow_set_different_1 (void **, void *);
309 static int dataflow_set_different_2 (void **, void *);
310 static bool dataflow_set_different (dataflow_set *, dataflow_set *);
311 static void dataflow_set_destroy (dataflow_set *);
313 static bool contains_symbol_ref (rtx);
314 static bool track_expr_p (tree);
315 static int count_uses (rtx *, void *);
316 static void count_uses_1 (rtx *, void *);
317 static void count_stores (rtx, rtx, void *);
318 static int add_uses (rtx *, void *);
319 static void add_uses_1 (rtx *, void *);
320 static void add_stores (rtx, rtx, void *);
321 static bool compute_bb_dataflow (basic_block);
322 static void vt_find_locations (void);
324 static void dump_attrs_list (attrs);
325 static int dump_variable (void **, void *);
326 static void dump_vars (htab_t);
327 static void dump_dataflow_set (dataflow_set *);
328 static void dump_dataflow_sets (void);
330 static void variable_was_changed (variable, htab_t);
331 static void set_frame_base_location (dataflow_set *, rtx);
332 static void set_variable_part (dataflow_set *, rtx, tree, HOST_WIDE_INT);
333 static void delete_variable_part (dataflow_set *, rtx, tree, HOST_WIDE_INT);
334 static int emit_note_insn_var_location (void **, void *);
335 static void emit_notes_for_changes (rtx, enum emit_note_where);
336 static int emit_notes_for_differences_1 (void **, void *);
337 static int emit_notes_for_differences_2 (void **, void *);
338 static void emit_notes_for_differences (rtx, dataflow_set *, dataflow_set *);
339 static void emit_notes_in_bb (basic_block);
340 static void vt_emit_notes (void);
342 static bool vt_get_decl_and_offset (rtx, tree *, HOST_WIDE_INT *);
343 static void vt_add_function_parameters (void);
344 static void vt_initialize (void);
345 static void vt_finalize (void);
347 /* Given a SET, calculate the amount of stack adjustment it contains
348 PRE- and POST-modifying stack pointer.
349 This function is similar to stack_adjust_offset. */
352 stack_adjust_offset_pre_post (rtx pattern, HOST_WIDE_INT *pre,
355 rtx src = SET_SRC (pattern);
356 rtx dest = SET_DEST (pattern);
359 if (dest == stack_pointer_rtx)
361 /* (set (reg sp) (plus (reg sp) (const_int))) */
362 code = GET_CODE (src);
363 if (! (code == PLUS || code == MINUS)
364 || XEXP (src, 0) != stack_pointer_rtx
365 || GET_CODE (XEXP (src, 1)) != CONST_INT)
369 *post += INTVAL (XEXP (src, 1));
371 *post -= INTVAL (XEXP (src, 1));
373 else if (GET_CODE (dest) == MEM)
375 /* (set (mem (pre_dec (reg sp))) (foo)) */
376 src = XEXP (dest, 0);
377 code = GET_CODE (src);
383 if (XEXP (src, 0) == stack_pointer_rtx)
385 rtx val = XEXP (XEXP (src, 1), 1);
386 /* We handle only adjustments by constant amount. */
387 if (GET_CODE (XEXP (src, 1)) != PLUS ||
388 GET_CODE (val) != CONST_INT)
390 if (code == PRE_MODIFY)
391 *pre -= INTVAL (val);
393 *post -= INTVAL (val);
399 if (XEXP (src, 0) == stack_pointer_rtx)
401 *pre += GET_MODE_SIZE (GET_MODE (dest));
407 if (XEXP (src, 0) == stack_pointer_rtx)
409 *post += GET_MODE_SIZE (GET_MODE (dest));
415 if (XEXP (src, 0) == stack_pointer_rtx)
417 *pre -= GET_MODE_SIZE (GET_MODE (dest));
423 if (XEXP (src, 0) == stack_pointer_rtx)
425 *post -= GET_MODE_SIZE (GET_MODE (dest));
436 /* Given an INSN, calculate the amount of stack adjustment it contains
437 PRE- and POST-modifying stack pointer. */
440 insn_stack_adjust_offset_pre_post (rtx insn, HOST_WIDE_INT *pre,
446 if (GET_CODE (PATTERN (insn)) == SET)
447 stack_adjust_offset_pre_post (PATTERN (insn), pre, post);
448 else if (GET_CODE (PATTERN (insn)) == PARALLEL
449 || GET_CODE (PATTERN (insn)) == SEQUENCE)
453 /* There may be stack adjustments inside compound insns. Search
455 for ( i = XVECLEN (PATTERN (insn), 0) - 1; i >= 0; i--)
456 if (GET_CODE (XVECEXP (PATTERN (insn), 0, i)) == SET)
457 stack_adjust_offset_pre_post (XVECEXP (PATTERN (insn), 0, i),
462 /* Compute stack adjustment in basic block BB. */
465 bb_stack_adjust_offset (basic_block bb)
467 HOST_WIDE_INT offset;
470 offset = VTI (bb)->in.stack_adjust;
471 for (i = 0; i < VTI (bb)->n_mos; i++)
473 if (VTI (bb)->mos[i].type == MO_ADJUST)
474 offset += VTI (bb)->mos[i].u.adjust;
475 else if (VTI (bb)->mos[i].type != MO_CALL)
477 if (GET_CODE (VTI (bb)->mos[i].u.loc) == MEM)
479 VTI (bb)->mos[i].u.loc
480 = adjust_stack_reference (VTI (bb)->mos[i].u.loc, -offset);
484 VTI (bb)->out.stack_adjust = offset;
487 /* Compute stack adjustment caused by function prolog. */
490 prologue_stack_adjust (void)
492 HOST_WIDE_INT offset = 0;
493 basic_block bb = ENTRY_BLOCK_PTR->next_bb;
500 end = NEXT_INSN (BB_END (bb));
501 for (insn = BB_HEAD (bb); insn != end; insn = NEXT_INSN (insn))
503 if (GET_CODE (insn) == NOTE
504 && NOTE_LINE_NUMBER (insn) == NOTE_INSN_PROLOGUE_END)
511 insn_stack_adjust_offset_pre_post (insn, &tmp, &tmp);
519 /* Compute stack adjustments for all blocks by traversing DFS tree.
520 Return true when the adjustments on all incoming edges are consistent.
521 Heavily borrowed from flow_depth_first_order_compute. */
524 vt_stack_adjustments (void)
529 /* Initialize entry block. */
530 VTI (ENTRY_BLOCK_PTR)->visited = true;
531 VTI (ENTRY_BLOCK_PTR)->out.stack_adjust = 0;
533 /* Allocate stack for back-tracking up CFG. */
534 stack = xmalloc ((n_basic_blocks + 1) * sizeof (edge));
537 /* Push the first edge on to the stack. */
538 stack[sp++] = ENTRY_BLOCK_PTR->succ;
546 /* Look at the edge on the top of the stack. */
551 /* Check if the edge destination has been visited yet. */
552 if (!VTI (dest)->visited)
554 VTI (dest)->visited = true;
555 VTI (dest)->in.stack_adjust = VTI (src)->out.stack_adjust;
556 bb_stack_adjust_offset (dest);
559 /* Since the DEST node has been visited for the first
560 time, check its successors. */
561 stack[sp++] = dest->succ;
565 /* Check whether the adjustments on the edges are the same. */
566 if (VTI (dest)->in.stack_adjust != VTI (src)->out.stack_adjust)
573 /* Go to the next edge. */
574 stack[sp - 1] = e->succ_next;
576 /* Return to previous level if there are no more edges. */
585 /* Adjust stack reference MEM by ADJUSTMENT bytes and return the new rtx. */
588 adjust_stack_reference (rtx mem, HOST_WIDE_INT adjustment)
593 adjusted_mem = copy_rtx (mem);
594 XEXP (adjusted_mem, 0) = replace_rtx (XEXP (adjusted_mem, 0),
596 gen_rtx_PLUS (Pmode, stack_pointer_rtx,
597 GEN_INT (adjustment)));
598 tmp = simplify_rtx (XEXP (adjusted_mem, 0));
600 XEXP (adjusted_mem, 0) = tmp;
605 /* The hash function for variable_htab, computes the hash value
606 from the declaration of variable X. */
609 variable_htab_hash (const void *x)
611 const variable v = (const variable) x;
613 return (VARIABLE_HASH_VAL (v->decl));
616 /* Compare the declaration of variable X with declaration Y. */
619 variable_htab_eq (const void *x, const void *y)
621 const variable v = (const variable) x;
622 const tree decl = (const tree) y;
624 return (VARIABLE_HASH_VAL (v->decl) == VARIABLE_HASH_VAL (decl));
627 /* Free the element of VARIABLE_HTAB (its type is struct variable_def). */
630 variable_htab_free (void *elem)
633 variable var = (variable) elem;
634 location_chain node, next;
636 #ifdef ENABLE_CHECKING
637 if (var->refcount <= 0)
642 if (var->refcount > 0)
645 for (i = 0; i < var->n_var_parts; i++)
647 for (node = var->var_part[i].loc_chain; node; node = next)
650 pool_free (loc_chain_pool, node);
652 var->var_part[i].loc_chain = NULL;
654 pool_free (var_pool, var);
657 /* Initialize the set (array) SET of attrs to empty lists. */
660 init_attrs_list_set (attrs *set)
664 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
668 /* Make the list *LISTP empty. */
671 attrs_list_clear (attrs *listp)
675 for (list = *listp; list; list = next)
678 pool_free (attrs_pool, list);
683 /* Return true if the pair of DECL and OFFSET is the member of the LIST. */
686 attrs_list_member (attrs list, tree decl, HOST_WIDE_INT offset)
688 for (; list; list = list->next)
689 if (list->decl == decl && list->offset == offset)
694 /* Insert the triplet DECL, OFFSET, LOC to the list *LISTP. */
697 attrs_list_insert (attrs *listp, tree decl, HOST_WIDE_INT offset, rtx loc)
701 list = pool_alloc (attrs_pool);
704 list->offset = offset;
709 /* Copy all nodes from SRC and create a list *DSTP of the copies. */
712 attrs_list_copy (attrs *dstp, attrs src)
716 attrs_list_clear (dstp);
717 for (; src; src = src->next)
719 n = pool_alloc (attrs_pool);
722 n->offset = src->offset;
728 /* Add all nodes from SRC which are not in *DSTP to *DSTP. */
731 attrs_list_union (attrs *dstp, attrs src)
733 for (; src; src = src->next)
735 if (!attrs_list_member (*dstp, src->decl, src->offset))
736 attrs_list_insert (dstp, src->decl, src->offset, src->loc);
740 /* Delete all variables from hash table VARS. */
743 vars_clear (htab_t vars)
748 /* Return a copy of a variable VAR and insert it to dataflow set SET. */
751 unshare_variable (dataflow_set *set, variable var)
757 new_var = pool_alloc (var_pool);
758 new_var->decl = var->decl;
759 new_var->refcount = 1;
761 new_var->n_var_parts = var->n_var_parts;
763 for (i = 0; i < var->n_var_parts; i++)
766 location_chain *nextp;
768 new_var->var_part[i].offset = var->var_part[i].offset;
769 nextp = &new_var->var_part[i].loc_chain;
770 for (node = var->var_part[i].loc_chain; node; node = node->next)
772 location_chain new_lc;
774 new_lc = pool_alloc (loc_chain_pool);
776 new_lc->loc = node->loc;
779 nextp = &new_lc->next;
782 /* We are at the basic block boundary when copying variable description
783 so set the CUR_LOC to be the first element of the chain. */
784 if (new_var->var_part[i].loc_chain)
785 new_var->var_part[i].cur_loc = new_var->var_part[i].loc_chain->loc;
787 new_var->var_part[i].cur_loc = NULL;
790 slot = htab_find_slot_with_hash (set->vars, new_var->decl,
791 VARIABLE_HASH_VAL (new_var->decl),
797 /* Add a variable from *SLOT to hash table DATA and increase its reference
801 vars_copy_1 (void **slot, void *data)
803 htab_t dst = (htab_t) data;
806 src = *(variable *) slot;
809 dstp = (variable *) htab_find_slot_with_hash (dst, src->decl,
810 VARIABLE_HASH_VAL (src->decl),
814 /* Continue traversing the hash table. */
818 /* Copy all variables from hash table SRC to hash table DST. */
821 vars_copy (htab_t dst, htab_t src)
824 htab_traverse (src, vars_copy_1, dst);
827 /* Delete current content of register LOC in dataflow set SET
828 and set the register to contain REG_EXPR (LOC), REG_OFFSET (LOC). */
831 var_reg_delete_and_set (dataflow_set *set, rtx loc)
833 tree decl = REG_EXPR (loc);
834 HOST_WIDE_INT offset = REG_OFFSET (loc);
838 nextp = &set->regs[REGNO (loc)];
839 for (node = *nextp; node; node = next)
842 if (node->decl != decl || node->offset != offset)
844 delete_variable_part (set, node->loc, node->decl, node->offset);
845 pool_free (attrs_pool, node);
854 if (set->regs[REGNO (loc)] == NULL)
855 attrs_list_insert (&set->regs[REGNO (loc)], decl, offset, loc);
856 set_variable_part (set, loc, decl, offset);
859 /* Delete current content of register LOC in dataflow set SET. */
862 var_reg_delete (dataflow_set *set, rtx loc)
864 attrs *reg = &set->regs[REGNO (loc)];
867 for (node = *reg; node; node = next)
870 delete_variable_part (set, node->loc, node->decl, node->offset);
871 pool_free (attrs_pool, node);
876 /* Delete content of register with number REGNO in dataflow set SET. */
879 var_regno_delete (dataflow_set *set, int regno)
881 attrs *reg = &set->regs[regno];
884 for (node = *reg; node; node = next)
887 delete_variable_part (set, node->loc, node->decl, node->offset);
888 pool_free (attrs_pool, node);
893 /* Delete and set the location part of variable MEM_EXPR (LOC)
894 in dataflow set SET to LOC.
895 Adjust the address first if it is stack pointer based. */
898 var_mem_delete_and_set (dataflow_set *set, rtx loc)
900 tree decl = MEM_EXPR (loc);
901 HOST_WIDE_INT offset = MEM_OFFSET (loc) ? INTVAL (MEM_OFFSET (loc)) : 0;
903 set_variable_part (set, loc, decl, offset);
906 /* Delete the location part LOC from dataflow set SET.
907 Adjust the address first if it is stack pointer based. */
910 var_mem_delete (dataflow_set *set, rtx loc)
912 tree decl = MEM_EXPR (loc);
913 HOST_WIDE_INT offset = MEM_OFFSET (loc) ? INTVAL (MEM_OFFSET (loc)) : 0;
915 delete_variable_part (set, loc, decl, offset);
918 /* Initialize dataflow set SET to be empty.
919 VARS_SIZE is the initial size of hash table VARS. */
922 dataflow_set_init (dataflow_set *set, int vars_size)
924 init_attrs_list_set (set->regs);
925 set->vars = htab_create (vars_size, variable_htab_hash, variable_htab_eq,
927 set->stack_adjust = 0;
930 /* Delete the contents of dataflow set SET. */
933 dataflow_set_clear (dataflow_set *set)
937 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
938 attrs_list_clear (&set->regs[i]);
940 vars_clear (set->vars);
943 /* Copy the contents of dataflow set SRC to DST. */
946 dataflow_set_copy (dataflow_set *dst, dataflow_set *src)
950 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
951 attrs_list_copy (&dst->regs[i], src->regs[i]);
953 vars_copy (dst->vars, src->vars);
954 dst->stack_adjust = src->stack_adjust;
957 /* Information for merging lists of locations for a given offset of variable.
959 struct variable_union_info
961 /* Node of the location chain. */
964 /* The sum of positions in the input chains. */
967 /* The position in the chains of SRC and DST dataflow sets. */
972 /* Compare function for qsort, order the structures by POS element. */
975 variable_union_info_cmp_pos (const void *n1, const void *n2)
977 const struct variable_union_info *i1 = n1;
978 const struct variable_union_info *i2 = n2;
980 if (i1->pos != i2->pos)
981 return i1->pos - i2->pos;
983 return (i1->pos_dst - i2->pos_dst);
986 /* Compute union of location parts of variable *SLOT and the same variable
987 from hash table DATA. Compute "sorted" union of the location chains
988 for common offsets, i.e. the locations of a variable part are sorted by
989 a priority where the priority is the sum of the positions in the 2 chains
990 (if a location is only in one list the position in the second list is
991 defined to be larger than the length of the chains).
992 When we are updating the location parts the newest location is in the
993 beginning of the chain, so when we do the described "sorted" union
994 we keep the newest locations in the beginning. */
997 variable_union (void **slot, void *data)
999 variable src, dst, *dstp;
1000 dataflow_set *set = (dataflow_set *) data;
1003 src = *(variable *) slot;
1004 dstp = (variable *) htab_find_slot_with_hash (set->vars, src->decl,
1005 VARIABLE_HASH_VAL (src->decl),
1011 /* If CUR_LOC of some variable part is not the first element of
1012 the location chain we are going to change it so we have to make
1013 a copy of the variable. */
1014 for (k = 0; k < src->n_var_parts; k++)
1016 if (src->var_part[k].loc_chain)
1018 #ifdef ENABLE_CHECKING
1019 if (src->var_part[k].cur_loc == NULL)
1022 if (src->var_part[k].cur_loc != src->var_part[k].loc_chain->loc)
1025 #ifdef ENABLE_CHECKING
1028 if (src->var_part[k].cur_loc != NULL)
1033 if (k < src->n_var_parts)
1034 unshare_variable (set, src);
1038 /* Continue traversing the hash table. */
1044 #ifdef ENABLE_CHECKING
1045 if (src->n_var_parts == 0)
1049 /* Count the number of location parts, result is K. */
1050 for (i = 0, j = 0, k = 0;
1051 i < src->n_var_parts && j < dst->n_var_parts; k++)
1053 if (src->var_part[i].offset == dst->var_part[j].offset)
1058 else if (src->var_part[i].offset < dst->var_part[j].offset)
1063 k += src->n_var_parts - i;
1064 k += dst->n_var_parts - j;
1065 #ifdef ENABLE_CHECKING
1066 /* We track only variables whose size is <= MAX_VAR_PARTS bytes
1067 thus there are at most MAX_VAR_PARTS different offsets. */
1068 if (k > MAX_VAR_PARTS)
1072 if (dst->refcount > 1 && dst->n_var_parts != k)
1073 dst = unshare_variable (set, dst);
1075 i = src->n_var_parts - 1;
1076 j = dst->n_var_parts - 1;
1077 dst->n_var_parts = k;
1079 for (k--; k >= 0; k--)
1081 location_chain node, node2;
1083 if (i >= 0 && j >= 0
1084 && src->var_part[i].offset == dst->var_part[j].offset)
1086 /* Compute the "sorted" union of the chains, i.e. the locations which
1087 are in both chains go first, they are sorted by the sum of
1088 positions in the chains. */
1091 struct variable_union_info *vui;
1093 /* If DST is shared compare the location chains.
1094 If they are different we will modify the chain in DST with
1095 high probability so make a copy of DST. */
1096 if (dst->refcount > 1)
1098 for (node = src->var_part[i].loc_chain,
1099 node2 = dst->var_part[j].loc_chain; node && node2;
1100 node = node->next, node2 = node2->next)
1102 if (!((GET_CODE (node2->loc) == REG
1103 && GET_CODE (node->loc) == REG
1104 && REGNO (node2->loc) == REGNO (node->loc))
1105 || rtx_equal_p (node2->loc, node->loc)))
1109 dst = unshare_variable (set, dst);
1113 for (node = src->var_part[i].loc_chain; node; node = node->next)
1116 for (node = dst->var_part[j].loc_chain; node; node = node->next)
1118 vui = xcalloc (src_l + dst_l, sizeof (struct variable_union_info));
1120 /* Fill in the locations from DST. */
1121 for (node = dst->var_part[j].loc_chain, jj = 0; node;
1122 node = node->next, jj++)
1125 vui[jj].pos_dst = jj;
1127 /* Value larger than a sum of 2 valid positions. */
1128 vui[jj].pos_src = src_l + dst_l;
1131 /* Fill in the locations from SRC. */
1133 for (node = src->var_part[i].loc_chain, ii = 0; node;
1134 node = node->next, ii++)
1136 /* Find location from NODE. */
1137 for (jj = 0; jj < dst_l; jj++)
1139 if ((GET_CODE (vui[jj].lc->loc) == REG
1140 && GET_CODE (node->loc) == REG
1141 && REGNO (vui[jj].lc->loc) == REGNO (node->loc))
1142 || rtx_equal_p (vui[jj].lc->loc, node->loc))
1144 vui[jj].pos_src = ii;
1148 if (jj >= dst_l) /* The location has not been found. */
1150 location_chain new_node;
1152 /* Copy the location from SRC. */
1153 new_node = pool_alloc (loc_chain_pool);
1154 new_node->loc = node->loc;
1155 vui[n].lc = new_node;
1156 vui[n].pos_src = ii;
1157 vui[n].pos_dst = src_l + dst_l;
1162 for (ii = 0; ii < src_l + dst_l; ii++)
1163 vui[ii].pos = vui[ii].pos_src + vui[ii].pos_dst;
1165 qsort (vui, n, sizeof (struct variable_union_info),
1166 variable_union_info_cmp_pos);
1168 /* Reconnect the nodes in sorted order. */
1169 for (ii = 1; ii < n; ii++)
1170 vui[ii - 1].lc->next = vui[ii].lc;
1171 vui[n - 1].lc->next = NULL;
1173 dst->var_part[k].loc_chain = vui[0].lc;
1174 dst->var_part[k].offset = dst->var_part[j].offset;
1180 else if ((i >= 0 && j >= 0
1181 && src->var_part[i].offset < dst->var_part[j].offset)
1184 dst->var_part[k] = dst->var_part[j];
1187 else if ((i >= 0 && j >= 0
1188 && src->var_part[i].offset > dst->var_part[j].offset)
1191 location_chain *nextp;
1193 /* Copy the chain from SRC. */
1194 nextp = &dst->var_part[k].loc_chain;
1195 for (node = src->var_part[i].loc_chain; node; node = node->next)
1197 location_chain new_lc;
1199 new_lc = pool_alloc (loc_chain_pool);
1200 new_lc->next = NULL;
1201 new_lc->loc = node->loc;
1204 nextp = &new_lc->next;
1207 dst->var_part[k].offset = src->var_part[i].offset;
1211 /* We are at the basic block boundary when computing union
1212 so set the CUR_LOC to be the first element of the chain. */
1213 if (dst->var_part[k].loc_chain)
1214 dst->var_part[k].cur_loc = dst->var_part[k].loc_chain->loc;
1216 dst->var_part[k].cur_loc = NULL;
1219 /* Continue traversing the hash table. */
1223 /* Compute union of dataflow sets SRC and DST and store it to DST. */
1226 dataflow_set_union (dataflow_set *dst, dataflow_set *src)
1230 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1231 attrs_list_union (&dst->regs[i], src->regs[i]);
1233 htab_traverse (src->vars, variable_union, dst);
1236 /* Flag whether two dataflow sets being compared contain different data. */
1238 dataflow_set_different_value;
1241 variable_part_different_p (variable_part *vp1, variable_part *vp2)
1243 location_chain lc1, lc2;
1245 if (!((GET_CODE (vp1->cur_loc) == REG
1246 && GET_CODE (vp2->cur_loc) == REG
1247 && REGNO (vp1->cur_loc) == REGNO (vp2->cur_loc))
1248 || rtx_equal_p (vp1->cur_loc, vp2->cur_loc)))
1251 for (lc1 = vp1->loc_chain; lc1; lc1 = lc1->next)
1253 for (lc2 = vp2->loc_chain; lc2; lc2 = lc2->next)
1255 if (GET_CODE (lc1->loc) == REG && GET_CODE (lc2->loc) == REG)
1257 if (REGNO (lc1->loc) == REGNO (lc2->loc))
1260 if (rtx_equal_p (lc1->loc, lc2->loc))
1269 /* Return true if variables VAR1 and VAR2 are different (only the first
1270 location in the list of locations is checked for each offset,
1271 i.e. when true is returned a note should be emitted). */
1274 variable_different_p (variable var1, variable var2)
1281 if (var1->n_var_parts != var2->n_var_parts)
1284 for (i = 0; i < var1->n_var_parts; i++)
1286 if (var1->var_part[i].offset != var2->var_part[i].offset)
1288 if (variable_part_different_p (&var1->var_part[i], &var2->var_part[i]))
1290 if (variable_part_different_p (&var2->var_part[i], &var1->var_part[i]))
1296 /* Compare variable *SLOT with the same variable in hash table DATA
1297 and set DATAFLOW_SET_DIFFERENT_VALUE if they are different. */
1300 dataflow_set_different_1 (void **slot, void *data)
1302 htab_t htab = (htab_t) data;
1303 variable var1, var2;
1305 var1 = *(variable *) slot;
1306 var2 = htab_find_with_hash (htab, var1->decl,
1307 VARIABLE_HASH_VAL (var1->decl));
1310 dataflow_set_different_value = true;
1312 /* Stop traversing the hash table. */
1316 if (variable_different_p (var1, var2))
1318 dataflow_set_different_value = true;
1320 /* Stop traversing the hash table. */
1324 /* Continue traversing the hash table. */
1328 /* Compare variable *SLOT with the same variable in hash table DATA
1329 and set DATAFLOW_SET_DIFFERENT_VALUE if they are different. */
1332 dataflow_set_different_2 (void **slot, void *data)
1334 htab_t htab = (htab_t) data;
1335 variable var1, var2;
1337 var1 = *(variable *) slot;
1338 var2 = htab_find_with_hash (htab, var1->decl,
1339 VARIABLE_HASH_VAL (var1->decl));
1342 dataflow_set_different_value = true;
1344 /* Stop traversing the hash table. */
1348 #ifdef ENABLE_CHECKING
1349 /* If both variables are defined they have been already checked for
1351 if (variable_different_p (var1, var2))
1355 /* Continue traversing the hash table. */
1359 /* Return true if dataflow sets OLD_SET and NEW_SET differ. */
1362 dataflow_set_different (dataflow_set *old_set, dataflow_set *new_set)
1364 dataflow_set_different_value = false;
1366 htab_traverse (old_set->vars, dataflow_set_different_1, new_set->vars);
1367 if (!dataflow_set_different_value)
1369 /* We have compared the variables which are in both hash tables
1370 so now only check whether there are some variables in NEW_SET->VARS
1371 which are not in OLD_SET->VARS. */
1372 htab_traverse (new_set->vars, dataflow_set_different_2, old_set->vars);
1374 return dataflow_set_different_value;
1377 /* Free the contents of dataflow set SET. */
1380 dataflow_set_destroy (dataflow_set *set)
1384 for (i = 0; i < FIRST_PSEUDO_REGISTER; i++)
1385 attrs_list_clear (&set->regs[i]);
1387 htab_delete (set->vars);
1391 /* Return true if RTL X contains a SYMBOL_REF. */
1394 contains_symbol_ref (rtx x)
1403 code = GET_CODE (x);
1404 if (code == SYMBOL_REF)
1407 fmt = GET_RTX_FORMAT (code);
1408 for (i = GET_RTX_LENGTH (code) - 1; i >= 0; i--)
1412 if (contains_symbol_ref (XEXP (x, i)))
1415 else if (fmt[i] == 'E')
1418 for (j = 0; j < XVECLEN (x, i); j++)
1419 if (contains_symbol_ref (XVECEXP (x, i, j)))
1427 /* Shall EXPR be tracked? */
1430 track_expr_p (tree expr)
1434 /* If EXPR is not a parameter or a variable do not track it. */
1435 if (TREE_CODE (expr) != VAR_DECL && TREE_CODE (expr) != PARM_DECL)
1438 /* It also must have a name... */
1439 if (!DECL_NAME (expr))
1442 /* ... and a RTL assigned to it. */
1443 decl_rtl = DECL_RTL_IF_SET (expr);
1447 /* Do not track EXPR if it should be ignored for debugging purposes. */
1448 if (DECL_IGNORED_P (expr))
1451 /* Do not track global variables until we are able to emit correct location
1453 if (TREE_STATIC (expr))
1456 /* When the EXPR is a DECL for alias of some variable (see example)
1457 the TREE_STATIC flag is not used. Disable tracking all DECLs whose
1458 DECL_RTL contains SYMBOL_REF.
1461 extern char **_dl_argv_internal __attribute__ ((alias ("_dl_argv")));
1464 if (GET_CODE (decl_rtl) == MEM
1465 && contains_symbol_ref (XEXP (decl_rtl, 0)))
1468 /* If RTX is a memory it should not be very large (because it would be
1469 an array or struct). */
1470 if (GET_CODE (decl_rtl) == MEM)
1472 /* Do not track structures and arrays. */
1473 if (GET_MODE (decl_rtl) == BLKmode)
1475 if (MEM_SIZE (decl_rtl)
1476 && INTVAL (MEM_SIZE (decl_rtl)) > MAX_VAR_PARTS)
1483 /* Count uses (register and memory references) LOC which will be tracked.
1484 INSN is instruction which the LOC is part of. */
1487 count_uses (rtx *loc, void *insn)
1489 basic_block bb = BLOCK_FOR_INSN ((rtx) insn);
1491 if (GET_CODE (*loc) == REG)
1493 #ifdef ENABLE_CHECKING
1494 if (REGNO (*loc) >= FIRST_PSEUDO_REGISTER)
1499 else if (GET_CODE (*loc) == MEM
1501 && track_expr_p (MEM_EXPR (*loc)))
1509 /* Helper function for finding all uses of REG/MEM in X in insn INSN. */
1512 count_uses_1 (rtx *x, void *insn)
1514 for_each_rtx (x, count_uses, insn);
1517 /* Count stores (register and memory references) LOC which will be tracked.
1518 INSN is instruction which the LOC is part of. */
1521 count_stores (rtx loc, rtx expr ATTRIBUTE_UNUSED, void *insn)
1523 count_uses (&loc, insn);
1526 /* Add uses (register and memory references) LOC which will be tracked
1527 to VTI (bb)->mos. INSN is instruction which the LOC is part of. */
1530 add_uses (rtx *loc, void *insn)
1532 if (GET_CODE (*loc) == REG)
1534 basic_block bb = BLOCK_FOR_INSN ((rtx) insn);
1535 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
1537 mo->type = ((REG_EXPR (*loc) && track_expr_p (REG_EXPR (*loc)))
1538 ? MO_USE : MO_USE_NO_VAR);
1540 mo->insn = (rtx) insn;
1542 else if (GET_CODE (*loc) == MEM
1544 && track_expr_p (MEM_EXPR (*loc)))
1546 basic_block bb = BLOCK_FOR_INSN ((rtx) insn);
1547 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
1551 mo->insn = (rtx) insn;
1557 /* Helper function for finding all uses of REG/MEM in X in insn INSN. */
1560 add_uses_1 (rtx *x, void *insn)
1562 for_each_rtx (x, add_uses, insn);
1565 /* Add stores (register and memory references) LOC which will be tracked
1566 to VTI (bb)->mos. EXPR is the RTL expression containing the store.
1567 INSN is instruction which the LOC is part of. */
1570 add_stores (rtx loc, rtx expr, void *insn)
1572 if (GET_CODE (loc) == REG)
1574 basic_block bb = BLOCK_FOR_INSN ((rtx) insn);
1575 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
1577 mo->type = ((GET_CODE (expr) != CLOBBER && REG_EXPR (loc)
1578 && track_expr_p (REG_EXPR (loc)))
1579 ? MO_SET : MO_CLOBBER);
1581 mo->insn = (rtx) insn;
1583 else if (GET_CODE (loc) == MEM
1585 && track_expr_p (MEM_EXPR (loc)))
1587 basic_block bb = BLOCK_FOR_INSN ((rtx) insn);
1588 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
1590 mo->type = GET_CODE (expr) == CLOBBER ? MO_CLOBBER : MO_SET;
1592 mo->insn = (rtx) insn;
1596 /* Compute the changes of variable locations in the basic block BB. */
1599 compute_bb_dataflow (basic_block bb)
1603 dataflow_set old_out;
1604 dataflow_set *in = &VTI (bb)->in;
1605 dataflow_set *out = &VTI (bb)->out;
1607 dataflow_set_init (&old_out, htab_elements (VTI (bb)->out.vars) + 3);
1608 dataflow_set_copy (&old_out, out);
1609 dataflow_set_copy (out, in);
1611 n = VTI (bb)->n_mos;
1612 for (i = 0; i < n; i++)
1614 switch (VTI (bb)->mos[i].type)
1617 for (r = 0; r < FIRST_PSEUDO_REGISTER; r++)
1618 if (TEST_HARD_REG_BIT (call_used_reg_set, r))
1619 var_regno_delete (out, r);
1625 rtx loc = VTI (bb)->mos[i].u.loc;
1627 if (GET_CODE (loc) == REG)
1628 var_reg_delete_and_set (out, loc);
1629 else if (GET_CODE (loc) == MEM)
1630 var_mem_delete_and_set (out, loc);
1637 rtx loc = VTI (bb)->mos[i].u.loc;
1639 if (GET_CODE (loc) == REG)
1640 var_reg_delete (out, loc);
1641 else if (GET_CODE (loc) == MEM)
1642 var_mem_delete (out, loc);
1650 out->stack_adjust += VTI (bb)->mos[i].u.adjust;
1651 base = gen_rtx_MEM (Pmode,
1652 gen_rtx_PLUS (Pmode, stack_pointer_rtx,
1653 GEN_INT (out->stack_adjust)));
1654 set_frame_base_location (out, base);
1660 changed = dataflow_set_different (&old_out, out);
1661 dataflow_set_destroy (&old_out);
1665 /* Find the locations of variables in the whole function. */
1668 vt_find_locations (void)
1670 fibheap_t worklist, pending, fibheap_swap;
1671 sbitmap visited, in_worklist, in_pending, sbitmap_swap;
1678 /* Compute reverse completion order of depth first search of the CFG
1679 so that the data-flow runs faster. */
1680 rc_order = xmalloc (n_basic_blocks * sizeof (int));
1681 bb_order = xmalloc (last_basic_block * sizeof (int));
1682 flow_depth_first_order_compute (NULL, rc_order);
1683 for (i = 0; i < n_basic_blocks; i++)
1684 bb_order[rc_order[i]] = i;
1687 worklist = fibheap_new ();
1688 pending = fibheap_new ();
1689 visited = sbitmap_alloc (last_basic_block);
1690 in_worklist = sbitmap_alloc (last_basic_block);
1691 in_pending = sbitmap_alloc (last_basic_block);
1692 sbitmap_zero (in_worklist);
1693 sbitmap_zero (in_pending);
1697 fibheap_insert (pending, bb_order[bb->index], bb);
1698 SET_BIT (in_pending, bb->index);
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))
1720 SET_BIT (visited, bb->index);
1722 /* Calculate the IN set as union of predecessor OUT sets. */
1723 dataflow_set_clear (&VTI (bb)->in);
1724 for (e = bb->pred; e; e = e->pred_next)
1726 dataflow_set_union (&VTI (bb)->in, &VTI (e->src)->out);
1729 changed = compute_bb_dataflow (bb);
1732 for (e = bb->succ; e; e = e->succ_next)
1734 if (e->dest == EXIT_BLOCK_PTR)
1740 if (TEST_BIT (visited, e->dest->index))
1742 if (!TEST_BIT (in_pending, e->dest->index))
1744 /* Send E->DEST to next round. */
1745 SET_BIT (in_pending, e->dest->index);
1746 fibheap_insert (pending,
1747 bb_order[e->dest->index],
1751 else if (!TEST_BIT (in_worklist, e->dest->index))
1753 /* Add E->DEST to current round. */
1754 SET_BIT (in_worklist, e->dest->index);
1755 fibheap_insert (worklist, bb_order[e->dest->index],
1765 fibheap_delete (worklist);
1766 fibheap_delete (pending);
1767 sbitmap_free (visited);
1768 sbitmap_free (in_worklist);
1769 sbitmap_free (in_pending);
1772 /* Print the content of the LIST to dump file. */
1775 dump_attrs_list (attrs list)
1777 for (; list; list = list->next)
1779 print_mem_expr (dump_file, list->decl);
1780 fprintf (dump_file, "+");
1781 fprintf (dump_file, HOST_WIDE_INT_PRINT_DEC, list->offset);
1783 fprintf (dump_file, "\n");
1786 /* Print the information about variable *SLOT to dump file. */
1789 dump_variable (void **slot, void *data ATTRIBUTE_UNUSED)
1791 variable var = *(variable *) slot;
1793 location_chain node;
1795 fprintf (dump_file, " name: %s\n",
1796 IDENTIFIER_POINTER (DECL_NAME (var->decl)));
1797 for (i = 0; i < var->n_var_parts; i++)
1799 fprintf (dump_file, " offset %ld\n",
1800 (long) var->var_part[i].offset);
1801 for (node = var->var_part[i].loc_chain; node; node = node->next)
1803 fprintf (dump_file, " ");
1804 print_rtl_single (dump_file, node->loc);
1808 /* Continue traversing the hash table. */
1812 /* Print the information about variables from hash table VARS to dump file. */
1815 dump_vars (htab_t vars)
1817 if (htab_elements (vars) > 0)
1819 fprintf (dump_file, "Variables:\n");
1820 htab_traverse (vars, dump_variable, NULL);
1824 /* Print the dataflow set SET to dump file. */
1827 dump_dataflow_set (dataflow_set *set)
1831 fprintf (dump_file, "Stack adjustment: ");
1832 fprintf (dump_file, HOST_WIDE_INT_PRINT_DEC, set->stack_adjust);
1833 fprintf (dump_file, "\n");
1834 for (i = 1; i < FIRST_PSEUDO_REGISTER; i++)
1838 fprintf (dump_file, "Reg %d:", i);
1839 dump_attrs_list (set->regs[i]);
1842 dump_vars (set->vars);
1843 fprintf (dump_file, "\n");
1846 /* Print the IN and OUT sets for each basic block to dump file. */
1849 dump_dataflow_sets (void)
1855 fprintf (dump_file, "\nBasic block %d:\n", bb->index);
1856 fprintf (dump_file, "IN:\n");
1857 dump_dataflow_set (&VTI (bb)->in);
1858 fprintf (dump_file, "OUT:\n");
1859 dump_dataflow_set (&VTI (bb)->out);
1863 /* Add variable VAR to the hash table of changed variables and
1864 if it has no locations delete it from hash table HTAB. */
1867 variable_was_changed (variable var, htab_t htab)
1869 hashval_t hash = VARIABLE_HASH_VAL (var->decl);
1875 slot = (variable *) htab_find_slot_with_hash (changed_variables,
1876 var->decl, hash, INSERT);
1878 if (htab && var->n_var_parts == 0)
1883 empty_var = pool_alloc (var_pool);
1884 empty_var->decl = var->decl;
1885 empty_var->refcount = 1;
1886 empty_var->n_var_parts = 0;
1889 old = htab_find_slot_with_hash (htab, var->decl, hash,
1892 htab_clear_slot (htab, old);
1901 #ifdef ENABLE_CHECKING
1905 if (var->n_var_parts == 0)
1907 void **slot = htab_find_slot_with_hash (htab, var->decl, hash,
1910 htab_clear_slot (htab, slot);
1915 /* Set the location of frame_base_decl to LOC in dataflow set SET. This
1916 function expects that
1917 frame_base_decl has already one location for offset 0 in the variable table.
1921 set_frame_base_location (dataflow_set *set, rtx loc)
1925 var = htab_find_with_hash (set->vars, frame_base_decl,
1926 VARIABLE_HASH_VAL (frame_base_decl));
1927 #ifdef ENABLE_CHECKING
1930 if (var->n_var_parts != 1)
1932 if (var->var_part[0].offset != 0)
1934 if (!var->var_part[0].loc_chain)
1938 /* If frame_base_decl is shared unshare it first. */
1939 if (var->refcount > 1)
1940 var = unshare_variable (set, var);
1942 var->var_part[0].loc_chain->loc = loc;
1943 var->var_part[0].cur_loc = loc;
1944 variable_was_changed (var, set->vars);
1947 /* Set the part of variable's location in the dataflow set SET. The variable
1948 part is specified by variable's declaration DECL and offset OFFSET and the
1949 part's location by LOC. */
1952 set_variable_part (dataflow_set *set, rtx loc, tree decl, HOST_WIDE_INT offset)
1955 location_chain node, next;
1956 location_chain *nextp;
1960 slot = htab_find_slot_with_hash (set->vars, decl,
1961 VARIABLE_HASH_VAL (decl), INSERT);
1964 /* Create new variable information. */
1965 var = pool_alloc (var_pool);
1968 var->n_var_parts = 1;
1969 var->var_part[0].offset = offset;
1970 var->var_part[0].loc_chain = NULL;
1971 var->var_part[0].cur_loc = NULL;
1977 var = (variable) *slot;
1979 /* Find the location part. */
1981 high = var->n_var_parts;
1984 pos = (low + high) / 2;
1985 if (var->var_part[pos].offset < offset)
1992 if (pos < var->n_var_parts && var->var_part[pos].offset == offset)
1994 node = var->var_part[pos].loc_chain;
1997 && ((GET_CODE (node->loc) == REG && GET_CODE (loc) == REG
1998 && REGNO (node->loc) == REGNO (loc))
1999 || rtx_equal_p (node->loc, loc)))
2001 /* LOC is in the beginning of the chain so we have nothing
2007 /* We have to make a copy of a shared variable. */
2008 if (var->refcount > 1)
2009 var = unshare_variable (set, var);
2014 /* We have not found the location part, new one will be created. */
2016 /* We have to make a copy of the shared variable. */
2017 if (var->refcount > 1)
2018 var = unshare_variable (set, var);
2020 #ifdef ENABLE_CHECKING
2021 /* We track only variables whose size is <= MAX_VAR_PARTS bytes
2022 thus there are at most MAX_VAR_PARTS different offsets. */
2023 if (var->n_var_parts >= MAX_VAR_PARTS)
2027 /* We have to move the elements of array starting at index low to the
2029 for (high = var->n_var_parts; high > low; high--)
2030 var->var_part[high] = var->var_part[high - 1];
2033 var->var_part[pos].offset = offset;
2034 var->var_part[pos].loc_chain = NULL;
2035 var->var_part[pos].cur_loc = NULL;
2039 /* Delete the location from the list. */
2040 nextp = &var->var_part[pos].loc_chain;
2041 for (node = var->var_part[pos].loc_chain; node; node = next)
2044 if ((GET_CODE (node->loc) == REG && GET_CODE (loc) == REG
2045 && REGNO (node->loc) == REGNO (loc))
2046 || rtx_equal_p (node->loc, loc))
2048 pool_free (loc_chain_pool, node);
2053 nextp = &node->next;
2056 /* Add the location to the beginning. */
2057 node = pool_alloc (loc_chain_pool);
2059 node->next = var->var_part[pos].loc_chain;
2060 var->var_part[pos].loc_chain = node;
2062 /* If no location was emitted do so. */
2063 if (var->var_part[pos].cur_loc == NULL)
2065 var->var_part[pos].cur_loc = loc;
2066 variable_was_changed (var, set->vars);
2070 /* Delete the part of variable's location from dataflow set SET. The variable
2071 part is specified by variable's declaration DECL and offset OFFSET and the
2072 part's location by LOC. */
2075 delete_variable_part (dataflow_set *set, rtx loc, tree decl,
2076 HOST_WIDE_INT offset)
2081 slot = htab_find_slot_with_hash (set->vars, decl, VARIABLE_HASH_VAL (decl),
2085 variable var = (variable) *slot;
2087 /* Find the location part. */
2089 high = var->n_var_parts;
2092 pos = (low + high) / 2;
2093 if (var->var_part[pos].offset < offset)
2100 if (pos < var->n_var_parts && var->var_part[pos].offset == offset)
2102 location_chain node, next;
2103 location_chain *nextp;
2106 if (var->refcount > 1)
2108 /* If the variable contains the location part we have to
2109 make a copy of the variable. */
2110 for (node = var->var_part[pos].loc_chain; node;
2113 if ((GET_CODE (node->loc) == REG && GET_CODE (loc) == REG
2114 && REGNO (node->loc) == REGNO (loc))
2115 || rtx_equal_p (node->loc, loc))
2117 var = unshare_variable (set, var);
2123 /* Delete the location part. */
2124 nextp = &var->var_part[pos].loc_chain;
2125 for (node = *nextp; node; node = next)
2128 if ((GET_CODE (node->loc) == REG && GET_CODE (loc) == REG
2129 && REGNO (node->loc) == REGNO (loc))
2130 || rtx_equal_p (node->loc, loc))
2132 pool_free (loc_chain_pool, node);
2137 nextp = &node->next;
2140 /* If we have deleted the location which was last emitted
2141 we have to emit new location so add the variable to set
2142 of changed variables. */
2143 if (var->var_part[pos].cur_loc
2144 && ((GET_CODE (loc) == REG
2145 && GET_CODE (var->var_part[pos].cur_loc) == REG
2146 && REGNO (loc) == REGNO (var->var_part[pos].cur_loc))
2147 || rtx_equal_p (loc, var->var_part[pos].cur_loc)))
2150 if (var->var_part[pos].loc_chain)
2151 var->var_part[pos].cur_loc = var->var_part[pos].loc_chain->loc;
2156 if (var->var_part[pos].loc_chain == NULL)
2159 while (pos < var->n_var_parts)
2161 var->var_part[pos] = var->var_part[pos + 1];
2166 variable_was_changed (var, set->vars);
2171 /* Emit the NOTE_INSN_VAR_LOCATION for variable *VARP. DATA contains
2172 additional parameters: WHERE specifies whether the note shall be emitted
2173 before of after instruction INSN. */
2176 emit_note_insn_var_location (void **varp, void *data)
2178 variable var = *(variable *) varp;
2179 rtx insn = ((emit_note_data *)data)->insn;
2180 enum emit_note_where where = ((emit_note_data *)data)->where;
2184 HOST_WIDE_INT last_limit;
2185 tree type_size_unit;
2187 #ifdef ENABLE_CHECKING
2194 for (i = 0; i < var->n_var_parts; i++)
2196 if (last_limit < var->var_part[i].offset)
2202 = (var->var_part[i].offset
2203 + GET_MODE_SIZE (GET_MODE (var->var_part[i].loc_chain->loc)));
2205 type_size_unit = TYPE_SIZE_UNIT (TREE_TYPE (var->decl));
2206 if ((unsigned HOST_WIDE_INT) last_limit < TREE_INT_CST_LOW (type_size_unit))
2209 if (where == EMIT_NOTE_AFTER_INSN)
2210 note = emit_note_after (NOTE_INSN_VAR_LOCATION, insn);
2212 note = emit_note_before (NOTE_INSN_VAR_LOCATION, insn);
2216 NOTE_VAR_LOCATION (note) = gen_rtx_VAR_LOCATION (VOIDmode, var->decl,
2219 else if (var->n_var_parts == 1)
2222 = gen_rtx_EXPR_LIST (VOIDmode,
2223 var->var_part[0].loc_chain->loc,
2224 GEN_INT (var->var_part[0].offset));
2226 NOTE_VAR_LOCATION (note) = gen_rtx_VAR_LOCATION (VOIDmode, var->decl,
2229 else if (var->n_var_parts)
2231 rtx argp[MAX_VAR_PARTS];
2234 for (i = 0; i < var->n_var_parts; i++)
2235 argp[i] = gen_rtx_EXPR_LIST (VOIDmode, var->var_part[i].loc_chain->loc,
2236 GEN_INT (var->var_part[i].offset));
2237 parallel = gen_rtx_PARALLEL (VOIDmode,
2238 gen_rtvec_v (var->n_var_parts, argp));
2239 NOTE_VAR_LOCATION (note) = gen_rtx_VAR_LOCATION (VOIDmode, var->decl,
2243 htab_clear_slot (changed_variables, varp);
2245 /* When there are no location parts the variable has been already
2246 removed from hash table and a new empty variable was created.
2247 Free the empty variable. */
2248 if (var->n_var_parts == 0)
2250 pool_free (var_pool, var);
2253 /* Continue traversing the hash table. */
2257 /* Emit NOTE_INSN_VAR_LOCATION note for each variable from a chain
2258 CHANGED_VARIABLES and delete this chain. WHERE specifies whether the notes
2259 shall be emitted before of after instruction INSN. */
2262 emit_notes_for_changes (rtx insn, enum emit_note_where where)
2264 emit_note_data data;
2268 htab_traverse (changed_variables, emit_note_insn_var_location, &data);
2271 /* Add variable *SLOT to the chain CHANGED_VARIABLES if it differs from the
2272 same variable in hash table DATA or is not there at all. */
2275 emit_notes_for_differences_1 (void **slot, void *data)
2277 htab_t new_vars = (htab_t) data;
2278 variable old_var, new_var;
2280 old_var = *(variable *) slot;
2281 new_var = htab_find_with_hash (new_vars, old_var->decl,
2282 VARIABLE_HASH_VAL (old_var->decl));
2286 /* Variable has disappeared. */
2289 empty_var = pool_alloc (var_pool);
2290 empty_var->decl = old_var->decl;
2291 empty_var->refcount = 1;
2292 empty_var->n_var_parts = 0;
2293 variable_was_changed (empty_var, NULL);
2295 else if (variable_different_p (old_var, new_var))
2297 variable_was_changed (new_var, NULL);
2300 /* Continue traversing the hash table. */
2304 /* Add variable *SLOT to the chain CHANGED_VARIABLES if it is not in hash
2308 emit_notes_for_differences_2 (void **slot, void *data)
2310 htab_t old_vars = (htab_t) data;
2311 variable old_var, new_var;
2313 new_var = *(variable *) slot;
2314 old_var = htab_find_with_hash (old_vars, new_var->decl,
2315 VARIABLE_HASH_VAL (new_var->decl));
2318 /* Variable has appeared. */
2319 variable_was_changed (new_var, NULL);
2322 /* Continue traversing the hash table. */
2326 /* Emit notes before INSN for differences between dataflow sets OLD_SET and
2330 emit_notes_for_differences (rtx insn, dataflow_set *old_set,
2331 dataflow_set *new_set)
2333 htab_traverse (old_set->vars, emit_notes_for_differences_1, new_set->vars);
2334 htab_traverse (new_set->vars, emit_notes_for_differences_2, old_set->vars);
2335 emit_notes_for_changes (insn, EMIT_NOTE_BEFORE_INSN);
2338 /* Emit the notes for changes of location parts in the basic block BB. */
2341 emit_notes_in_bb (basic_block bb)
2346 dataflow_set_init (&set, htab_elements (VTI (bb)->in.vars) + 3);
2347 dataflow_set_copy (&set, &VTI (bb)->in);
2349 for (i = 0; i < VTI (bb)->n_mos; i++)
2351 rtx insn = VTI (bb)->mos[i].insn;
2353 switch (VTI (bb)->mos[i].type)
2359 for (r = 0; r < FIRST_PSEUDO_REGISTER; r++)
2360 if (TEST_HARD_REG_BIT (call_used_reg_set, r))
2362 var_regno_delete (&set, r);
2364 emit_notes_for_changes (insn, EMIT_NOTE_AFTER_INSN);
2371 rtx loc = VTI (bb)->mos[i].u.loc;
2373 if (GET_CODE (loc) == REG)
2374 var_reg_delete_and_set (&set, loc);
2376 var_mem_delete_and_set (&set, loc);
2378 if (VTI (bb)->mos[i].type == MO_USE)
2379 emit_notes_for_changes (insn, EMIT_NOTE_BEFORE_INSN);
2381 emit_notes_for_changes (insn, EMIT_NOTE_AFTER_INSN);
2388 rtx loc = VTI (bb)->mos[i].u.loc;
2390 if (GET_CODE (loc) == REG)
2391 var_reg_delete (&set, loc);
2393 var_mem_delete (&set, loc);
2395 if (VTI (bb)->mos[i].type == MO_USE_NO_VAR)
2396 emit_notes_for_changes (insn, EMIT_NOTE_BEFORE_INSN);
2398 emit_notes_for_changes (insn, EMIT_NOTE_AFTER_INSN);
2406 set.stack_adjust += VTI (bb)->mos[i].u.adjust;
2407 base = gen_rtx_MEM (Pmode,
2408 gen_rtx_PLUS (Pmode, stack_pointer_rtx,
2409 GEN_INT (set.stack_adjust)));
2410 set_frame_base_location (&set, base);
2411 emit_notes_for_changes (insn, EMIT_NOTE_AFTER_INSN);
2416 dataflow_set_destroy (&set);
2419 /* Emit notes for the whole function. */
2422 vt_emit_notes (void)
2425 dataflow_set *last_out;
2428 #ifdef ENABLE_CHECKING
2429 if (htab_elements (changed_variables))
2433 /* Enable emitting notes by functions (mainly by set_variable_part and
2434 delete_variable_part). */
2437 dataflow_set_init (&empty, 7);
2442 /* Emit the notes for changes of variable locations between two
2443 subsequent basic blocks. */
2444 emit_notes_for_differences (BB_HEAD (bb), last_out, &VTI (bb)->in);
2446 /* Emit the notes for the changes in the basic block itself. */
2447 emit_notes_in_bb (bb);
2449 last_out = &VTI (bb)->out;
2451 dataflow_set_destroy (&empty);
2455 /* If there is a declaration and offset associated with register/memory RTL
2456 assign declaration to *DECLP and offset to *OFFSETP, and return true. */
2459 vt_get_decl_and_offset (rtx rtl, tree *declp, HOST_WIDE_INT *offsetp)
2461 if (GET_CODE (rtl) == REG)
2463 if (REG_ATTRS (rtl))
2465 *declp = REG_EXPR (rtl);
2466 *offsetp = REG_OFFSET (rtl);
2470 else if (GET_CODE (rtl) == MEM)
2472 if (MEM_ATTRS (rtl))
2474 *declp = MEM_EXPR (rtl);
2475 *offsetp = MEM_OFFSET (rtl) ? INTVAL (MEM_OFFSET (rtl)) : 0;
2482 /* Insert function parameters to IN and OUT sets of ENTRY_BLOCK. */
2485 vt_add_function_parameters (void)
2488 HOST_WIDE_INT stack_adjust = 0;
2490 if (!frame_pointer_needed)
2491 stack_adjust = prologue_stack_adjust ();
2493 for (parm = DECL_ARGUMENTS (current_function_decl);
2494 parm; parm = TREE_CHAIN (parm))
2496 rtx decl_rtl = DECL_RTL_IF_SET (parm);
2497 rtx incoming = DECL_INCOMING_RTL (parm);
2499 HOST_WIDE_INT offset;
2502 if (TREE_CODE (parm) != PARM_DECL)
2505 if (!DECL_NAME (parm))
2508 if (!decl_rtl || !incoming)
2511 if (GET_MODE (decl_rtl) == BLKmode || GET_MODE (incoming) == BLKmode)
2514 if (!vt_get_decl_and_offset (incoming, &decl, &offset))
2515 if (!vt_get_decl_and_offset (decl_rtl, &decl, &offset))
2521 #ifdef ENABLE_CHECKING
2526 incoming = eliminate_regs (incoming, 0, NULL_RTX);
2527 if (!frame_pointer_needed && GET_CODE (incoming) == MEM)
2528 incoming = adjust_stack_reference (incoming, -stack_adjust);
2529 out = &VTI (ENTRY_BLOCK_PTR)->out;
2531 if (GET_CODE (incoming) == REG)
2533 #ifdef ENABLE_CHECKING
2534 if (REGNO (incoming) >= FIRST_PSEUDO_REGISTER)
2537 attrs_list_insert (&out->regs[REGNO (incoming)],
2538 parm, offset, incoming);
2539 set_variable_part (out, incoming, parm, offset);
2541 else if (GET_CODE (incoming) == MEM)
2543 set_variable_part (out, incoming, parm, offset);
2548 /* Allocate and initialize the data structures for variable tracking
2549 and parse the RTL to get the micro operations. */
2552 vt_initialize (void)
2556 alloc_aux_for_blocks (sizeof (struct variable_tracking_info_def));
2561 HOST_WIDE_INT pre, post;
2563 /* Count the number of micro operations. */
2564 VTI (bb)->n_mos = 0;
2565 for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb));
2566 insn = NEXT_INSN (insn))
2570 if (!frame_pointer_needed)
2572 insn_stack_adjust_offset_pre_post (insn, &pre, &post);
2578 note_uses (&PATTERN (insn), count_uses_1, insn);
2579 note_stores (PATTERN (insn), count_stores, insn);
2580 if (GET_CODE (insn) == CALL_INSN)
2585 /* Add the micro-operations to the array. */
2586 VTI (bb)->mos = xmalloc (VTI (bb)->n_mos
2587 * sizeof (struct micro_operation_def));
2588 VTI (bb)->n_mos = 0;
2589 for (insn = BB_HEAD (bb); insn != NEXT_INSN (BB_END (bb));
2590 insn = NEXT_INSN (insn))
2596 if (!frame_pointer_needed)
2598 insn_stack_adjust_offset_pre_post (insn, &pre, &post);
2601 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
2603 mo->type = MO_ADJUST;
2609 n1 = VTI (bb)->n_mos;
2610 note_uses (&PATTERN (insn), add_uses_1, insn);
2611 n2 = VTI (bb)->n_mos - 1;
2613 /* Order the MO_USEs to be before MO_USE_NO_VARs. */
2616 while (n1 < n2 && VTI (bb)->mos[n1].type == MO_USE)
2618 while (n1 < n2 && VTI (bb)->mos[n2].type == MO_USE_NO_VAR)
2624 sw = VTI (bb)->mos[n1];
2625 VTI (bb)->mos[n1] = VTI (bb)->mos[n2];
2626 VTI (bb)->mos[n2] = sw;
2630 if (GET_CODE (insn) == CALL_INSN)
2632 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
2638 n1 = VTI (bb)->n_mos;
2639 note_stores (PATTERN (insn), add_stores, insn);
2640 n2 = VTI (bb)->n_mos - 1;
2642 /* Order the MO_SETs to be before MO_CLOBBERs. */
2645 while (n1 < n2 && VTI (bb)->mos[n1].type == MO_SET)
2647 while (n1 < n2 && VTI (bb)->mos[n2].type == MO_CLOBBER)
2653 sw = VTI (bb)->mos[n1];
2654 VTI (bb)->mos[n1] = VTI (bb)->mos[n2];
2655 VTI (bb)->mos[n2] = sw;
2659 if (!frame_pointer_needed && post)
2661 micro_operation *mo = VTI (bb)->mos + VTI (bb)->n_mos++;
2663 mo->type = MO_ADJUST;
2664 mo->u.adjust = post;
2671 /* Init the IN and OUT sets. */
2674 VTI (bb)->visited = false;
2675 dataflow_set_init (&VTI (bb)->in, 7);
2676 dataflow_set_init (&VTI (bb)->out, 7);
2679 attrs_pool = create_alloc_pool ("attrs_def pool",
2680 sizeof (struct attrs_def), 1024);
2681 var_pool = create_alloc_pool ("variable_def pool",
2682 sizeof (struct variable_def), 64);
2683 loc_chain_pool = create_alloc_pool ("location_chain_def pool",
2684 sizeof (struct location_chain_def),
2686 changed_variables = htab_create (10, variable_htab_hash, variable_htab_eq,
2688 vt_add_function_parameters ();
2690 if (!frame_pointer_needed)
2694 /* Create fake variable for tracking stack pointer changes. */
2695 frame_base_decl = make_node (VAR_DECL);
2696 DECL_NAME (frame_base_decl) = get_identifier ("___frame_base_decl");
2697 TREE_TYPE (frame_base_decl) = char_type_node;
2698 DECL_ARTIFICIAL (frame_base_decl) = 1;
2700 /* Set its initial "location". */
2701 base = gen_rtx_MEM (Pmode, stack_pointer_rtx);
2702 set_variable_part (&VTI (ENTRY_BLOCK_PTR)->out, base, frame_base_decl, 0);
2706 frame_base_decl = NULL;
2710 /* Free the data structures needed for variable tracking. */
2719 free (VTI (bb)->mos);
2724 dataflow_set_destroy (&VTI (bb)->in);
2725 dataflow_set_destroy (&VTI (bb)->out);
2727 free_aux_for_blocks ();
2728 free_alloc_pool (attrs_pool);
2729 free_alloc_pool (var_pool);
2730 free_alloc_pool (loc_chain_pool);
2731 htab_delete (changed_variables);
2734 /* The entry point to variable tracking pass. */
2737 variable_tracking_main (void)
2739 if (n_basic_blocks > 500 && n_edges / n_basic_blocks >= 20)
2742 mark_dfs_back_edges ();
2744 if (!frame_pointer_needed)
2746 if (!vt_stack_adjustments ())
2753 vt_find_locations ();
2758 dump_dataflow_sets ();
2759 dump_flow_info (dump_file);