1 /* Allocation for dataflow support routines.
2 Copyright (C) 1999-2022 Free Software Foundation, Inc.
3 Originally contributed by Michael P. Hayes
4 (m.hayes@elec.canterbury.ac.nz, mhayes@redhat.com)
5 Major rewrite contributed by Danny Berlin (dberlin@dberlin.org)
6 and Kenneth Zadeck (zadeck@naturalbridge.com).
8 This file is part of GCC.
10 GCC is free software; you can redistribute it and/or modify it under
11 the terms of the GNU General Public License as published by the Free
12 Software Foundation; either version 3, or (at your option) any later
15 GCC is distributed in the hope that it will be useful, but WITHOUT ANY
16 WARRANTY; without even the implied warranty of MERCHANTABILITY or
17 FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
20 You should have received a copy of the GNU General Public License
21 along with GCC; see the file COPYING3. If not see
22 <http://www.gnu.org/licenses/>. */
27 The files in this collection (df*.c,df.h) provide a general framework
28 for solving dataflow problems. The global dataflow is performed using
29 a good implementation of iterative dataflow analysis.
31 The file df-problems.cc provides problem instance for the most common
32 dataflow problems: reaching defs, upward exposed uses, live variables,
33 uninitialized variables, def-use chains, and use-def chains. However,
34 the interface allows other dataflow problems to be defined as well.
36 Dataflow analysis is available in most of the rtl backend (the parts
37 between pass_df_initialize and pass_df_finish). It is quite likely
38 that these boundaries will be expanded in the future. The only
39 requirement is that there be a correct control flow graph.
41 There are three variations of the live variable problem that are
42 available whenever dataflow is available. The LR problem finds the
43 areas that can reach a use of a variable, the UR problems finds the
44 areas that can be reached from a definition of a variable. The LIVE
45 problem finds the intersection of these two areas.
47 There are several optional problems. These can be enabled when they
48 are needed and disabled when they are not needed.
50 Dataflow problems are generally solved in three layers. The bottom
51 layer is called scanning where a data structure is built for each rtl
52 insn that describes the set of defs and uses of that insn. Scanning
53 is generally kept up to date, i.e. as the insns changes, the scanned
54 version of that insn changes also. There are various mechanisms for
55 making this happen and are described in the INCREMENTAL SCANNING
58 In the middle layer, basic blocks are scanned to produce transfer
59 functions which describe the effects of that block on the global
60 dataflow solution. The transfer functions are only rebuilt if the
61 some instruction within the block has changed.
63 The top layer is the dataflow solution itself. The dataflow solution
64 is computed by using an efficient iterative solver and the transfer
65 functions. The dataflow solution must be recomputed whenever the
66 control changes or if one of the transfer function changes.
71 Here is an example of using the dataflow routines.
73 df_[chain,live,note,rd]_add_problem (flags);
75 df_set_blocks (blocks);
81 df_finish_pass (false);
83 DF_[chain,live,note,rd]_ADD_PROBLEM adds a problem, defined by an
84 instance to struct df_problem, to the set of problems solved in this
85 instance of df. All calls to add a problem for a given instance of df
86 must occur before the first call to DF_ANALYZE.
88 Problems can be dependent on other problems. For instance, solving
89 def-use or use-def chains is dependent on solving reaching
90 definitions. As long as these dependencies are listed in the problem
91 definition, the order of adding the problems is not material.
92 Otherwise, the problems will be solved in the order of calls to
93 df_add_problem. Note that it is not necessary to have a problem. In
94 that case, df will just be used to do the scanning.
98 DF_SET_BLOCKS is an optional call used to define a region of the
99 function on which the analysis will be performed. The normal case is
100 to analyze the entire function and no call to df_set_blocks is made.
101 DF_SET_BLOCKS only effects the blocks that are effected when computing
102 the transfer functions and final solution. The insn level information
103 is always kept up to date.
105 When a subset is given, the analysis behaves as if the function only
106 contains those blocks and any edges that occur directly between the
107 blocks in the set. Care should be taken to call df_set_blocks right
108 before the call to analyze in order to eliminate the possibility that
109 optimizations that reorder blocks invalidate the bitvector.
111 DF_ANALYZE causes all of the defined problems to be (re)solved. When
112 DF_ANALYZE is completes, the IN and OUT sets for each basic block
113 contain the computer information. The DF_*_BB_INFO macros can be used
114 to access these bitvectors. All deferred rescannings are down before
115 the transfer functions are recomputed.
117 DF_DUMP can then be called to dump the information produce to some
118 file. This calls DF_DUMP_START, to print the information that is not
119 basic block specific, and then calls DF_DUMP_TOP and DF_DUMP_BOTTOM
120 for each block to print the basic specific information. These parts
121 can all be called separately as part of a larger dump function.
124 DF_FINISH_PASS causes df_remove_problem to be called on all of the
125 optional problems. It also causes any insns whose scanning has been
126 deferred to be rescanned as well as clears all of the changeable flags.
127 Setting the pass manager TODO_df_finish flag causes this function to
128 be run. However, the pass manager will call df_finish_pass AFTER the
129 pass dumping has been done, so if you want to see the results of the
130 optional problems in the pass dumps, use the TODO flag rather than
131 calling the function yourself.
135 There are four ways of doing the incremental scanning:
137 1) Immediate rescanning - Calls to df_insn_rescan, df_notes_rescan,
138 df_bb_delete, df_insn_change_bb have been added to most of
139 the low level service functions that maintain the cfg and change
140 rtl. Calling and of these routines many cause some number of insns
143 For most modern rtl passes, this is certainly the easiest way to
144 manage rescanning the insns. This technique also has the advantage
145 that the scanning information is always correct and can be relied
146 upon even after changes have been made to the instructions. This
147 technique is contra indicated in several cases:
149 a) If def-use chains OR use-def chains (but not both) are built,
150 using this is SIMPLY WRONG. The problem is that when a ref is
151 deleted that is the target of an edge, there is not enough
152 information to efficiently find the source of the edge and
153 delete the edge. This leaves a dangling reference that may
156 b) If def-use chains AND use-def chains are built, this may
157 produce unexpected results. The problem is that the incremental
158 scanning of an insn does not know how to repair the chains that
159 point into an insn when the insn changes. So the incremental
160 scanning just deletes the chains that enter and exit the insn
161 being changed. The dangling reference issue in (a) is not a
162 problem here, but if the pass is depending on the chains being
163 maintained after insns have been modified, this technique will
164 not do the correct thing.
166 c) If the pass modifies insns several times, this incremental
167 updating may be expensive.
169 d) If the pass modifies all of the insns, as does register
170 allocation, it is simply better to rescan the entire function.
172 2) Deferred rescanning - Calls to df_insn_rescan, df_notes_rescan, and
173 df_insn_delete do not immediately change the insn but instead make
174 a note that the insn needs to be rescanned. The next call to
175 df_analyze, df_finish_pass, or df_process_deferred_rescans will
176 cause all of the pending rescans to be processed.
178 This is the technique of choice if either 1a, 1b, or 1c are issues
179 in the pass. In the case of 1a or 1b, a call to df_finish_pass
180 (either manually or via TODO_df_finish) should be made before the
181 next call to df_analyze or df_process_deferred_rescans.
183 This mode is also used by a few passes that still rely on note_uses,
184 note_stores and rtx iterators instead of using the DF data. This
185 can be said to fall under case 1c.
187 To enable this mode, call df_set_flags (DF_DEFER_INSN_RESCAN).
188 (This mode can be cleared by calling df_clear_flags
189 (DF_DEFER_INSN_RESCAN) but this does not cause the deferred insns to
192 3) Total rescanning - In this mode the rescanning is disabled.
193 Only when insns are deleted is the df information associated with
194 it also deleted. At the end of the pass, a call must be made to
195 df_insn_rescan_all. This method is used by the register allocator
196 since it generally changes each insn multiple times (once for each ref)
197 and does not need to make use of the updated scanning information.
199 4) Do it yourself - In this mechanism, the pass updates the insns
200 itself using the low level df primitives. Currently no pass does
201 this, but it has the advantage that it is quite efficient given
202 that the pass generally has exact knowledge of what it is changing.
206 Scanning produces a `struct df_ref' data structure (ref) is allocated
207 for every register reference (def or use) and this records the insn
208 and bb the ref is found within. The refs are linked together in
209 chains of uses and defs for each insn and for each register. Each ref
210 also has a chain field that links all the use refs for a def or all
211 the def refs for a use. This is used to create use-def or def-use
214 Different optimizations have different needs. Ultimately, only
215 register allocation and schedulers should be using the bitmaps
216 produced for the live register and uninitialized register problems.
217 The rest of the backend should be upgraded to using and maintaining
218 the linked information such as def use or use def chains.
223 While incremental bitmaps are not worthwhile to maintain, incremental
224 chains may be perfectly reasonable. The fastest way to build chains
225 from scratch or after significant modifications is to build reaching
226 definitions (RD) and build the chains from this.
228 However, general algorithms for maintaining use-def or def-use chains
229 are not practical. The amount of work to recompute the chain any
230 chain after an arbitrary change is large. However, with a modest
231 amount of work it is generally possible to have the application that
232 uses the chains keep them up to date. The high level knowledge of
233 what is really happening is essential to crafting efficient
234 incremental algorithms.
236 As for the bit vector problems, there is no interface to give a set of
237 blocks over with to resolve the iteration. In general, restarting a
238 dataflow iteration is difficult and expensive. Again, the best way to
239 keep the dataflow information up to data (if this is really what is
240 needed) it to formulate a problem specific solution.
242 There are fine grained calls for creating and deleting references from
243 instructions in df-scan.cc. However, these are not currently connected
244 to the engine that resolves the dataflow equations.
249 The basic object is a DF_REF (reference) and this may either be a
250 DEF (definition) or a USE of a register.
252 These are linked into a variety of lists; namely reg-def, reg-use,
253 insn-def, insn-use, def-use, and use-def lists. For example, the
254 reg-def lists contain all the locations that define a given register
255 while the insn-use lists contain all the locations that use a
258 Note that the reg-def and reg-use chains are generally short for
259 pseudos and long for the hard registers.
263 1) The df insn information is kept in an array of DF_INSN_INFO objects.
264 The array is indexed by insn uid, and every DF_REF points to the
265 DF_INSN_INFO object of the insn that contains the reference.
267 2) Each insn has three sets of refs, which are linked into one of three
268 lists: The insn's defs list (accessed by the DF_INSN_INFO_DEFS,
269 DF_INSN_DEFS, or DF_INSN_UID_DEFS macros), the insn's uses list
270 (accessed by the DF_INSN_INFO_USES, DF_INSN_USES, or
271 DF_INSN_UID_USES macros) or the insn's eq_uses list (accessed by the
272 DF_INSN_INFO_EQ_USES, DF_INSN_EQ_USES or DF_INSN_UID_EQ_USES macros).
273 The latter list are the list of references in REG_EQUAL or REG_EQUIV
274 notes. These macros produce a ref (or NULL), the rest of the list
275 can be obtained by traversal of the NEXT_REF field (accessed by the
276 DF_REF_NEXT_REF macro.) There is no significance to the ordering of
277 the uses or refs in an instruction.
279 3) Each insn has a logical uid field (LUID) which is stored in the
280 DF_INSN_INFO object for the insn. The LUID field is accessed by
281 the DF_INSN_INFO_LUID, DF_INSN_LUID, and DF_INSN_UID_LUID macros.
282 When properly set, the LUID is an integer that numbers each insn in
283 the basic block, in order from the start of the block.
284 The numbers are only correct after a call to df_analyze. They will
285 rot after insns are added deleted or moved round.
289 There are 4 ways to obtain access to refs:
291 1) References are divided into two categories, REAL and ARTIFICIAL.
293 REAL refs are associated with instructions.
295 ARTIFICIAL refs are associated with basic blocks. The heads of
296 these lists can be accessed by calling df_get_artificial_defs or
297 df_get_artificial_uses for the particular basic block.
299 Artificial defs and uses occur both at the beginning and ends of blocks.
301 For blocks that are at the destination of eh edges, the
302 artificial uses and defs occur at the beginning. The defs relate
303 to the registers specified in EH_RETURN_DATA_REGNO and the uses
304 relate to the registers specified in EH_USES. Logically these
305 defs and uses should really occur along the eh edge, but there is
306 no convenient way to do this. Artificial defs that occur at the
307 beginning of the block have the DF_REF_AT_TOP flag set.
309 Artificial uses occur at the end of all blocks. These arise from
310 the hard registers that are always live, such as the stack
311 register and are put there to keep the code from forgetting about
314 Artificial defs occur at the end of the entry block. These arise
315 from registers that are live at entry to the function.
317 2) There are three types of refs: defs, uses and eq_uses. (Eq_uses are
318 uses that appear inside a REG_EQUAL or REG_EQUIV note.)
320 All of the eq_uses, uses and defs associated with each pseudo or
321 hard register may be linked in a bidirectional chain. These are
322 called reg-use or reg_def chains. If the changeable flag
323 DF_EQ_NOTES is set when the chains are built, the eq_uses will be
324 treated like uses. If it is not set they are ignored.
326 The first use, eq_use or def for a register can be obtained using
327 the DF_REG_USE_CHAIN, DF_REG_EQ_USE_CHAIN or DF_REG_DEF_CHAIN
328 macros. Subsequent uses for the same regno can be obtained by
329 following the next_reg field of the ref. The number of elements in
330 each of the chains can be found by using the DF_REG_USE_COUNT,
331 DF_REG_EQ_USE_COUNT or DF_REG_DEF_COUNT macros.
333 In previous versions of this code, these chains were ordered. It
334 has not been practical to continue this practice.
336 3) If def-use or use-def chains are built, these can be traversed to
337 get to other refs. If the flag DF_EQ_NOTES has been set, the chains
338 include the eq_uses. Otherwise these are ignored when building the
341 4) An array of all of the uses (and an array of all of the defs) can
342 be built. These arrays are indexed by the value in the id
343 structure. These arrays are only lazily kept up to date, and that
344 process can be expensive. To have these arrays built, call
345 df_reorganize_defs or df_reorganize_uses. If the flag DF_EQ_NOTES
346 has been set the array will contain the eq_uses. Otherwise these
347 are ignored when building the array and assigning the ids. Note
348 that the values in the id field of a ref may change across calls to
349 df_analyze or df_reorganize_defs or df_reorganize_uses.
351 If the only use of this array is to find all of the refs, it is
352 better to traverse all of the registers and then traverse all of
353 reg-use or reg-def chains.
357 Embedded addressing side-effects, such as POST_INC or PRE_INC, generate
358 both a use and a def. These are both marked read/write to show that they
359 are dependent. For example, (set (reg 40) (mem (post_inc (reg 42))))
360 will generate a use of reg 42 followed by a def of reg 42 (both marked
361 read/write). Similarly, (set (reg 40) (mem (pre_dec (reg 41))))
362 generates a use of reg 41 then a def of reg 41 (both marked read/write),
363 even though reg 41 is decremented before it is used for the memory
364 address in this second example.
366 A set to a REG inside a ZERO_EXTRACT, or a set to a non-paradoxical SUBREG
367 for which the number of word_mode units covered by the outer mode is
368 smaller than that covered by the inner mode, invokes a read-modify-write
369 operation. We generate both a use and a def and again mark them
372 Paradoxical subreg writes do not leave a trace of the old content, so they
373 are write-only operations.
379 #include "coretypes.h"
383 #include "memmodel.h"
384 #include "emit-rtl.h"
386 #include "tree-pass.h"
389 static void *df_get_bb_info (struct dataflow *, unsigned int);
390 static void df_set_bb_info (struct dataflow *, unsigned int, void *);
391 static void df_clear_bb_info (struct dataflow *, unsigned int);
393 static void df_set_clean_cfg (void);
396 /* The obstack on which regsets are allocated. */
397 struct bitmap_obstack reg_obstack;
399 /* An obstack for bitmap not related to specific dataflow problems.
400 This obstack should e.g. be used for bitmaps with a short life time
401 such as temporary bitmaps. */
403 bitmap_obstack df_bitmap_obstack;
406 /*----------------------------------------------------------------------------
407 Functions to create, destroy and manipulate an instance of df.
408 ----------------------------------------------------------------------------*/
412 /* Add PROBLEM (and any dependent problems) to the DF instance. */
415 df_add_problem (const struct df_problem *problem)
417 struct dataflow *dflow;
420 /* First try to add the dependent problem. */
421 if (problem->dependent_problem)
422 df_add_problem (problem->dependent_problem);
424 /* Check to see if this problem has already been defined. If it
425 has, just return that instance, if not, add it to the end of the
427 dflow = df->problems_by_index[problem->id];
431 /* Make a new one and add it to the end. */
432 dflow = XCNEW (struct dataflow);
433 dflow->problem = problem;
434 dflow->computed = false;
435 dflow->solutions_dirty = true;
436 df->problems_by_index[dflow->problem->id] = dflow;
438 /* Keep the defined problems ordered by index. This solves the
439 problem that RI will use the information from UREC if UREC has
440 been defined, or from LIVE if LIVE is defined and otherwise LR.
441 However for this to work, the computation of RI must be pushed
442 after which ever of those problems is defined, but we do not
443 require any of those except for LR to have actually been
445 df->num_problems_defined++;
446 for (i = df->num_problems_defined - 2; i >= 0; i--)
448 if (problem->id < df->problems_in_order[i]->problem->id)
449 df->problems_in_order[i+1] = df->problems_in_order[i];
452 df->problems_in_order[i+1] = dflow;
456 df->problems_in_order[0] = dflow;
460 /* Set the MASK flags in the DFLOW problem. The old flags are
461 returned. If a flag is not allowed to be changed this will fail if
462 checking is enabled. */
464 df_set_flags (int changeable_flags)
466 int old_flags = df->changeable_flags;
467 df->changeable_flags |= changeable_flags;
472 /* Clear the MASK flags in the DFLOW problem. The old flags are
473 returned. If a flag is not allowed to be changed this will fail if
474 checking is enabled. */
476 df_clear_flags (int changeable_flags)
478 int old_flags = df->changeable_flags;
479 df->changeable_flags &= ~changeable_flags;
484 /* Set the blocks that are to be considered for analysis. If this is
485 not called or is called with null, the entire function in
489 df_set_blocks (bitmap blocks)
494 bitmap_print (dump_file, blocks, "setting blocks to analyze ", "\n");
495 if (df->blocks_to_analyze)
497 /* This block is called to change the focus from one subset
500 auto_bitmap diff (&df_bitmap_obstack);
501 bitmap_and_compl (diff, df->blocks_to_analyze, blocks);
502 for (p = 0; p < df->num_problems_defined; p++)
504 struct dataflow *dflow = df->problems_in_order[p];
505 if (dflow->optional_p && dflow->problem->reset_fun)
506 dflow->problem->reset_fun (df->blocks_to_analyze);
507 else if (dflow->problem->free_blocks_on_set_blocks)
510 unsigned int bb_index;
512 EXECUTE_IF_SET_IN_BITMAP (diff, 0, bb_index, bi)
514 basic_block bb = BASIC_BLOCK_FOR_FN (cfun, bb_index);
517 void *bb_info = df_get_bb_info (dflow, bb_index);
518 dflow->problem->free_bb_fun (bb, bb_info);
519 df_clear_bb_info (dflow, bb_index);
527 /* This block of code is executed to change the focus from
528 the entire function to a subset. */
529 bitmap_head blocks_to_reset;
530 bool initialized = false;
532 for (p = 0; p < df->num_problems_defined; p++)
534 struct dataflow *dflow = df->problems_in_order[p];
535 if (dflow->optional_p && dflow->problem->reset_fun)
540 bitmap_initialize (&blocks_to_reset, &df_bitmap_obstack);
541 FOR_ALL_BB_FN (bb, cfun)
543 bitmap_set_bit (&blocks_to_reset, bb->index);
546 dflow->problem->reset_fun (&blocks_to_reset);
550 bitmap_clear (&blocks_to_reset);
552 df->blocks_to_analyze = BITMAP_ALLOC (&df_bitmap_obstack);
554 bitmap_copy (df->blocks_to_analyze, blocks);
555 df->analyze_subset = true;
559 /* This block is executed to reset the focus to the entire
562 fprintf (dump_file, "clearing blocks_to_analyze\n");
563 if (df->blocks_to_analyze)
565 BITMAP_FREE (df->blocks_to_analyze);
566 df->blocks_to_analyze = NULL;
568 df->analyze_subset = false;
571 /* Setting the blocks causes the refs to be unorganized since only
572 the refs in the blocks are seen. */
573 df_maybe_reorganize_def_refs (DF_REF_ORDER_NO_TABLE);
574 df_maybe_reorganize_use_refs (DF_REF_ORDER_NO_TABLE);
575 df_mark_solutions_dirty ();
579 /* Delete a DFLOW problem (and any problems that depend on this
583 df_remove_problem (struct dataflow *dflow)
585 const struct df_problem *problem;
591 problem = dflow->problem;
592 gcc_assert (problem->remove_problem_fun);
594 /* Delete any problems that depended on this problem first. */
595 for (i = 0; i < df->num_problems_defined; i++)
596 if (df->problems_in_order[i]->problem->dependent_problem == problem)
597 df_remove_problem (df->problems_in_order[i]);
599 /* Now remove this problem. */
600 for (i = 0; i < df->num_problems_defined; i++)
601 if (df->problems_in_order[i] == dflow)
604 for (j = i + 1; j < df->num_problems_defined; j++)
605 df->problems_in_order[j-1] = df->problems_in_order[j];
606 df->problems_in_order[j-1] = NULL;
607 df->num_problems_defined--;
611 (problem->remove_problem_fun) ();
612 df->problems_by_index[problem->id] = NULL;
616 /* Remove all of the problems that are not permanent. Scanning, LR
617 and (at -O2 or higher) LIVE are permanent, the rest are removable.
618 Also clear all of the changeable_flags. */
621 df_finish_pass (bool verify ATTRIBUTE_UNUSED)
625 #ifdef ENABLE_DF_CHECKING
632 df_maybe_reorganize_def_refs (DF_REF_ORDER_NO_TABLE);
633 df_maybe_reorganize_use_refs (DF_REF_ORDER_NO_TABLE);
635 #ifdef ENABLE_DF_CHECKING
636 saved_flags = df->changeable_flags;
639 /* We iterate over problems by index as each problem removed will
640 lead to problems_in_order to be reordered. */
641 for (i = 0; i < DF_LAST_PROBLEM_PLUS1; i++)
643 struct dataflow *dflow = df->problems_by_index[i];
645 if (dflow && dflow->optional_p)
646 df_remove_problem (dflow);
649 /* Clear all of the flags. */
650 df->changeable_flags = 0;
651 df_process_deferred_rescans ();
653 /* Set the focus back to the whole function. */
654 if (df->blocks_to_analyze)
656 BITMAP_FREE (df->blocks_to_analyze);
657 df->blocks_to_analyze = NULL;
658 df_mark_solutions_dirty ();
659 df->analyze_subset = false;
662 #ifdef ENABLE_DF_CHECKING
663 /* Verification will fail in DF_NO_INSN_RESCAN. */
664 if (!(saved_flags & DF_NO_INSN_RESCAN))
666 df_lr_verify_transfer_functions ();
668 df_live_verify_transfer_functions ();
676 if (flag_checking && verify)
677 df->changeable_flags |= DF_VERIFY_SCHEDULED;
681 /* Set up the dataflow instance for the entire back end. */
684 rest_of_handle_df_initialize (void)
687 df = XCNEW (class df_d);
688 df->changeable_flags = 0;
690 bitmap_obstack_initialize (&df_bitmap_obstack);
692 /* Set this to a conservative value. Stack_ptr_mod will compute it
694 crtl->sp_is_unchanging = 0;
696 df_scan_add_problem ();
697 df_scan_alloc (NULL);
699 /* These three problems are permanent. */
700 df_lr_add_problem ();
702 df_live_add_problem ();
704 df->postorder = XNEWVEC (int, last_basic_block_for_fn (cfun));
705 df->n_blocks = post_order_compute (df->postorder, true, true);
706 inverted_post_order_compute (&df->postorder_inverted);
707 gcc_assert ((unsigned) df->n_blocks == df->postorder_inverted.length ());
709 df->hard_regs_live_count = XCNEWVEC (unsigned int, FIRST_PSEUDO_REGISTER);
712 /* After reload, some ports add certain bits to regs_ever_live so
713 this cannot be reset. */
714 df_compute_regs_ever_live (true);
716 df_compute_regs_ever_live (false);
723 const pass_data pass_data_df_initialize_opt =
727 OPTGROUP_NONE, /* optinfo_flags */
728 TV_DF_SCAN, /* tv_id */
729 0, /* properties_required */
730 0, /* properties_provided */
731 0, /* properties_destroyed */
732 0, /* todo_flags_start */
733 0, /* todo_flags_finish */
736 class pass_df_initialize_opt : public rtl_opt_pass
739 pass_df_initialize_opt (gcc::context *ctxt)
740 : rtl_opt_pass (pass_data_df_initialize_opt, ctxt)
743 /* opt_pass methods: */
744 bool gate (function *) final override { return optimize > 0; }
745 unsigned int execute (function *) final override
747 return rest_of_handle_df_initialize ();
750 }; // class pass_df_initialize_opt
755 make_pass_df_initialize_opt (gcc::context *ctxt)
757 return new pass_df_initialize_opt (ctxt);
763 const pass_data pass_data_df_initialize_no_opt =
766 "no-opt dfinit", /* name */
767 OPTGROUP_NONE, /* optinfo_flags */
768 TV_DF_SCAN, /* tv_id */
769 0, /* properties_required */
770 0, /* properties_provided */
771 0, /* properties_destroyed */
772 0, /* todo_flags_start */
773 0, /* todo_flags_finish */
776 class pass_df_initialize_no_opt : public rtl_opt_pass
779 pass_df_initialize_no_opt (gcc::context *ctxt)
780 : rtl_opt_pass (pass_data_df_initialize_no_opt, ctxt)
783 /* opt_pass methods: */
784 bool gate (function *) final override { return optimize == 0; }
785 unsigned int execute (function *) final override
787 return rest_of_handle_df_initialize ();
790 }; // class pass_df_initialize_no_opt
795 make_pass_df_initialize_no_opt (gcc::context *ctxt)
797 return new pass_df_initialize_no_opt (ctxt);
801 /* Free all the dataflow info and the DF structure. This should be
802 called from the df_finish macro which also NULLs the parm. */
805 rest_of_handle_df_finish (void)
811 for (i = 0; i < df->num_problems_defined; i++)
813 struct dataflow *dflow = df->problems_in_order[i];
814 dflow->problem->free_fun ();
817 free (df->postorder);
818 df->postorder_inverted.release ();
819 free (df->hard_regs_live_count);
823 bitmap_obstack_release (&df_bitmap_obstack);
830 const pass_data pass_data_df_finish =
833 "dfinish", /* name */
834 OPTGROUP_NONE, /* optinfo_flags */
836 0, /* properties_required */
837 0, /* properties_provided */
838 0, /* properties_destroyed */
839 0, /* todo_flags_start */
840 0, /* todo_flags_finish */
843 class pass_df_finish : public rtl_opt_pass
846 pass_df_finish (gcc::context *ctxt)
847 : rtl_opt_pass (pass_data_df_finish, ctxt)
850 /* opt_pass methods: */
851 unsigned int execute (function *) final override
853 return rest_of_handle_df_finish ();
856 }; // class pass_df_finish
861 make_pass_df_finish (gcc::context *ctxt)
863 return new pass_df_finish (ctxt);
870 /*----------------------------------------------------------------------------
871 The general data flow analysis engine.
872 ----------------------------------------------------------------------------*/
874 /* Helper function for df_worklist_dataflow.
875 Propagate the dataflow forward.
876 Given a BB_INDEX, do the dataflow propagation
877 and set bits on for successors in PENDING
878 if the out set of the dataflow has changed.
880 AGE specify time when BB was visited last time.
881 AGE of 0 means we are visiting for first time and need to
882 compute transfer function to initialize datastructures.
883 Otherwise we re-do transfer function only if something change
884 while computing confluence functions.
885 We need to compute confluence only of basic block that are younger
886 then last visit of the BB.
888 Return true if BB info has changed. This is always the case
889 in the first visit. */
892 df_worklist_propagate_forward (struct dataflow *dataflow,
894 unsigned *bbindex_to_postorder,
897 vec<int> &last_change_age,
902 basic_block bb = BASIC_BLOCK_FOR_FN (cfun, bb_index);
905 /* Calculate <conf_op> of incoming edges. */
906 if (EDGE_COUNT (bb->preds) > 0)
907 FOR_EACH_EDGE (e, ei, bb->preds)
909 if (bbindex_to_postorder[e->src->index] < last_change_age.length ()
910 && age <= last_change_age[bbindex_to_postorder[e->src->index]]
911 && bitmap_bit_p (considered, e->src->index))
912 changed |= dataflow->problem->con_fun_n (e);
914 else if (dataflow->problem->con_fun_0)
915 dataflow->problem->con_fun_0 (bb);
918 && dataflow->problem->trans_fun (bb_index))
920 /* The out set of this block has changed.
921 Propagate to the outgoing blocks. */
922 FOR_EACH_EDGE (e, ei, bb->succs)
924 unsigned ob_index = e->dest->index;
926 if (bitmap_bit_p (considered, ob_index))
927 bitmap_set_bit (pending, bbindex_to_postorder[ob_index]);
935 /* Helper function for df_worklist_dataflow.
936 Propagate the dataflow backward. */
939 df_worklist_propagate_backward (struct dataflow *dataflow,
941 unsigned *bbindex_to_postorder,
944 vec<int> &last_change_age,
949 basic_block bb = BASIC_BLOCK_FOR_FN (cfun, bb_index);
952 /* Calculate <conf_op> of incoming edges. */
953 if (EDGE_COUNT (bb->succs) > 0)
954 FOR_EACH_EDGE (e, ei, bb->succs)
956 if (bbindex_to_postorder[e->dest->index] < last_change_age.length ()
957 && age <= last_change_age[bbindex_to_postorder[e->dest->index]]
958 && bitmap_bit_p (considered, e->dest->index))
959 changed |= dataflow->problem->con_fun_n (e);
961 else if (dataflow->problem->con_fun_0)
962 dataflow->problem->con_fun_0 (bb);
965 && dataflow->problem->trans_fun (bb_index))
967 /* The out set of this block has changed.
968 Propagate to the outgoing blocks. */
969 FOR_EACH_EDGE (e, ei, bb->preds)
971 unsigned ob_index = e->src->index;
973 if (bitmap_bit_p (considered, ob_index))
974 bitmap_set_bit (pending, bbindex_to_postorder[ob_index]);
981 /* Main dataflow solver loop.
983 DATAFLOW is problem we are solving, PENDING is worklist of basic blocks we
985 BLOCK_IN_POSTORDER is array of size N_BLOCKS specifying postorder in BBs and
986 BBINDEX_TO_POSTORDER is array mapping back BB->index to postorder position.
987 PENDING will be freed.
989 The worklists are bitmaps indexed by postorder positions.
991 The function implements standard algorithm for dataflow solving with two
992 worklists (we are processing WORKLIST and storing new BBs to visit in
995 As an optimization we maintain ages when BB was changed (stored in
996 last_change_age) and when it was last visited (stored in last_visit_age).
997 This avoids need to re-do confluence function for edges to basic blocks
998 whose source did not change since destination was visited last time. */
1001 df_worklist_dataflow_doublequeue (struct dataflow *dataflow,
1004 int *blocks_in_postorder,
1005 unsigned *bbindex_to_postorder,
1008 enum df_flow_dir dir = dataflow->problem->dir;
1010 bitmap worklist = BITMAP_ALLOC (&df_bitmap_obstack);
1013 vec<int> last_visit_age = vNULL;
1014 vec<int> last_change_age = vNULL;
1017 last_visit_age.safe_grow_cleared (n_blocks, true);
1018 last_change_age.safe_grow_cleared (n_blocks, true);
1020 /* Double-queueing. Worklist is for the current iteration,
1021 and pending is for the next. */
1022 while (!bitmap_empty_p (pending))
1027 std::swap (pending, worklist);
1029 EXECUTE_IF_SET_IN_BITMAP (worklist, 0, index, bi)
1034 bitmap_clear_bit (pending, index);
1035 bb_index = blocks_in_postorder[index];
1036 prev_age = last_visit_age[index];
1037 if (dir == DF_FORWARD)
1038 changed = df_worklist_propagate_forward (dataflow, bb_index,
1039 bbindex_to_postorder,
1040 pending, considered,
1044 changed = df_worklist_propagate_backward (dataflow, bb_index,
1045 bbindex_to_postorder,
1046 pending, considered,
1049 last_visit_age[index] = ++age;
1051 last_change_age[index] = age;
1053 bitmap_clear (worklist);
1056 BITMAP_FREE (worklist);
1057 BITMAP_FREE (pending);
1058 last_visit_age.release ();
1059 last_change_age.release ();
1061 /* Dump statistics. */
1063 fprintf (dump_file, "df_worklist_dataflow_doublequeue:"
1064 " n_basic_blocks %d n_edges %d"
1065 " count %d (%5.2g)\n",
1066 n_basic_blocks_for_fn (cfun), n_edges_for_fn (cfun),
1067 dcount, dcount / (double)n_basic_blocks_for_fn (cfun));
1070 /* Worklist-based dataflow solver. It uses sbitmap as a worklist,
1071 with "n"-th bit representing the n-th block in the reverse-postorder order.
1072 The solver is a double-queue algorithm similar to the "double stack" solver
1073 from Cooper, Harvey and Kennedy, "Iterative data-flow analysis, Revisited".
1074 The only significant difference is that the worklist in this implementation
1075 is always sorted in RPO of the CFG visiting direction. */
1078 df_worklist_dataflow (struct dataflow *dataflow,
1079 bitmap blocks_to_consider,
1080 int *blocks_in_postorder,
1083 bitmap pending = BITMAP_ALLOC (&df_bitmap_obstack);
1085 unsigned int *bbindex_to_postorder;
1088 enum df_flow_dir dir = dataflow->problem->dir;
1090 gcc_assert (dir != DF_NONE);
1092 /* BBINDEX_TO_POSTORDER maps the bb->index to the reverse postorder. */
1093 bbindex_to_postorder = XNEWVEC (unsigned int,
1094 last_basic_block_for_fn (cfun));
1096 /* Initialize the array to an out-of-bound value. */
1097 for (i = 0; i < last_basic_block_for_fn (cfun); i++)
1098 bbindex_to_postorder[i] = last_basic_block_for_fn (cfun);
1100 /* Initialize the considered map. */
1101 auto_sbitmap considered (last_basic_block_for_fn (cfun));
1102 bitmap_clear (considered);
1103 EXECUTE_IF_SET_IN_BITMAP (blocks_to_consider, 0, index, bi)
1105 bitmap_set_bit (considered, index);
1108 /* Initialize the mapping of block index to postorder. */
1109 for (i = 0; i < n_blocks; i++)
1111 bbindex_to_postorder[blocks_in_postorder[i]] = i;
1112 /* Add all blocks to the worklist. */
1113 bitmap_set_bit (pending, i);
1116 /* Initialize the problem. */
1117 if (dataflow->problem->init_fun)
1118 dataflow->problem->init_fun (blocks_to_consider);
1121 df_worklist_dataflow_doublequeue (dataflow, pending, considered,
1122 blocks_in_postorder,
1123 bbindex_to_postorder,
1125 free (bbindex_to_postorder);
1129 /* Remove the entries not in BLOCKS from the LIST of length LEN, preserving
1130 the order of the remaining entries. Returns the length of the resulting
1134 df_prune_to_subcfg (int list[], unsigned len, bitmap blocks)
1138 for (act = 0, last = 0; act < len; act++)
1139 if (bitmap_bit_p (blocks, list[act]))
1140 list[last++] = list[act];
1146 /* Execute dataflow analysis on a single dataflow problem.
1148 BLOCKS_TO_CONSIDER are the blocks whose solution can either be
1149 examined or will be computed. For calls from DF_ANALYZE, this is
1150 the set of blocks that has been passed to DF_SET_BLOCKS.
1154 df_analyze_problem (struct dataflow *dflow,
1155 bitmap blocks_to_consider,
1156 int *postorder, int n_blocks)
1158 timevar_push (dflow->problem->tv_id);
1160 /* (Re)Allocate the datastructures necessary to solve the problem. */
1161 if (dflow->problem->alloc_fun)
1162 dflow->problem->alloc_fun (blocks_to_consider);
1164 #ifdef ENABLE_DF_CHECKING
1165 if (dflow->problem->verify_start_fun)
1166 dflow->problem->verify_start_fun ();
1169 /* Set up the problem and compute the local information. */
1170 if (dflow->problem->local_compute_fun)
1171 dflow->problem->local_compute_fun (blocks_to_consider);
1173 /* Solve the equations. */
1174 if (dflow->problem->dataflow_fun)
1175 dflow->problem->dataflow_fun (dflow, blocks_to_consider,
1176 postorder, n_blocks);
1178 /* Massage the solution. */
1179 if (dflow->problem->finalize_fun)
1180 dflow->problem->finalize_fun (blocks_to_consider);
1182 #ifdef ENABLE_DF_CHECKING
1183 if (dflow->problem->verify_end_fun)
1184 dflow->problem->verify_end_fun ();
1187 timevar_pop (dflow->problem->tv_id);
1189 dflow->computed = true;
1193 /* Analyze dataflow info. */
1200 /* These should be the same. */
1201 gcc_assert ((unsigned) df->n_blocks == df->postorder_inverted.length ());
1203 /* We need to do this before the df_verify_all because this is
1204 not kept incrementally up to date. */
1205 df_compute_regs_ever_live (false);
1206 df_process_deferred_rescans ();
1209 fprintf (dump_file, "df_analyze called\n");
1211 #ifndef ENABLE_DF_CHECKING
1212 if (df->changeable_flags & DF_VERIFY_SCHEDULED)
1216 /* Skip over the DF_SCAN problem. */
1217 for (i = 1; i < df->num_problems_defined; i++)
1219 struct dataflow *dflow = df->problems_in_order[i];
1220 if (dflow->solutions_dirty)
1222 if (dflow->problem->dir == DF_FORWARD)
1223 df_analyze_problem (dflow,
1224 df->blocks_to_analyze,
1225 df->postorder_inverted.address (),
1226 df->postorder_inverted.length ());
1228 df_analyze_problem (dflow,
1229 df->blocks_to_analyze,
1235 if (!df->analyze_subset)
1237 BITMAP_FREE (df->blocks_to_analyze);
1238 df->blocks_to_analyze = NULL;
1242 df_set_clean_cfg ();
1246 /* Analyze dataflow info. */
1251 bitmap current_all_blocks = BITMAP_ALLOC (&df_bitmap_obstack);
1253 free (df->postorder);
1254 df->postorder = XNEWVEC (int, last_basic_block_for_fn (cfun));
1255 df->n_blocks = post_order_compute (df->postorder, true, true);
1256 df->postorder_inverted.truncate (0);
1257 inverted_post_order_compute (&df->postorder_inverted);
1259 for (int i = 0; i < df->n_blocks; i++)
1260 bitmap_set_bit (current_all_blocks, df->postorder[i]);
1264 /* Verify that POSTORDER_INVERTED only contains blocks reachable from
1266 for (unsigned int i = 0; i < df->postorder_inverted.length (); i++)
1267 gcc_assert (bitmap_bit_p (current_all_blocks,
1268 df->postorder_inverted[i]));
1271 /* Make sure that we have pruned any unreachable blocks from these
1273 if (df->analyze_subset)
1275 bitmap_and_into (df->blocks_to_analyze, current_all_blocks);
1276 df->n_blocks = df_prune_to_subcfg (df->postorder,
1277 df->n_blocks, df->blocks_to_analyze);
1278 unsigned int newlen = df_prune_to_subcfg (df->postorder_inverted.address (),
1279 df->postorder_inverted.length (),
1280 df->blocks_to_analyze);
1281 df->postorder_inverted.truncate (newlen);
1282 BITMAP_FREE (current_all_blocks);
1286 df->blocks_to_analyze = current_all_blocks;
1287 current_all_blocks = NULL;
1293 /* Compute the reverse top sort order of the sub-CFG specified by LOOP.
1294 Returns the number of blocks which is always loop->num_nodes. */
1297 loop_post_order_compute (int *post_order, class loop *loop)
1299 edge_iterator *stack;
1301 int post_order_num = 0;
1303 /* Allocate stack for back-tracking up CFG. */
1304 stack = XNEWVEC (edge_iterator, loop->num_nodes + 1);
1307 /* Allocate bitmap to track nodes that have been visited. */
1308 auto_bitmap visited;
1310 /* Push the first edge on to the stack. */
1311 stack[sp++] = ei_start (loop_preheader_edge (loop)->src->succs);
1319 /* Look at the edge on the top of the stack. */
1321 src = ei_edge (ei)->src;
1322 dest = ei_edge (ei)->dest;
1324 /* Check if the edge destination has been visited yet and mark it
1326 if (flow_bb_inside_loop_p (loop, dest)
1327 && bitmap_set_bit (visited, dest->index))
1329 if (EDGE_COUNT (dest->succs) > 0)
1330 /* Since the DEST node has been visited for the first
1331 time, check its successors. */
1332 stack[sp++] = ei_start (dest->succs);
1334 post_order[post_order_num++] = dest->index;
1338 if (ei_one_before_end_p (ei)
1339 && src != loop_preheader_edge (loop)->src)
1340 post_order[post_order_num++] = src->index;
1342 if (!ei_one_before_end_p (ei))
1343 ei_next (&stack[sp - 1]);
1351 return post_order_num;
1354 /* Compute the reverse top sort order of the inverted sub-CFG specified
1355 by LOOP. Returns the number of blocks which is always loop->num_nodes. */
1358 loop_inverted_post_order_compute (vec<int> *post_order, class loop *loop)
1361 edge_iterator *stack;
1364 post_order->reserve_exact (loop->num_nodes);
1366 /* Allocate stack for back-tracking up CFG. */
1367 stack = XNEWVEC (edge_iterator, loop->num_nodes + 1);
1370 /* Allocate bitmap to track nodes that have been visited. */
1371 auto_bitmap visited;
1373 /* Put all latches into the initial work list. In theory we'd want
1374 to start from loop exits but then we'd have the special case of
1375 endless loops. It doesn't really matter for DF iteration order and
1376 handling latches last is probably even better. */
1377 stack[sp++] = ei_start (loop->header->preds);
1378 bitmap_set_bit (visited, loop->header->index);
1380 /* The inverted traversal loop. */
1386 /* Look at the edge on the top of the stack. */
1388 bb = ei_edge (ei)->dest;
1389 pred = ei_edge (ei)->src;
1391 /* Check if the predecessor has been visited yet and mark it
1393 if (flow_bb_inside_loop_p (loop, pred)
1394 && bitmap_set_bit (visited, pred->index))
1396 if (EDGE_COUNT (pred->preds) > 0)
1397 /* Since the predecessor node has been visited for the first
1398 time, check its predecessors. */
1399 stack[sp++] = ei_start (pred->preds);
1401 post_order->quick_push (pred->index);
1405 if (flow_bb_inside_loop_p (loop, bb)
1406 && ei_one_before_end_p (ei))
1407 post_order->quick_push (bb->index);
1409 if (!ei_one_before_end_p (ei))
1410 ei_next (&stack[sp - 1]);
1420 /* Analyze dataflow info for the basic blocks contained in LOOP. */
1423 df_analyze_loop (class loop *loop)
1425 free (df->postorder);
1427 df->postorder = XNEWVEC (int, loop->num_nodes);
1428 df->postorder_inverted.truncate (0);
1429 df->n_blocks = loop_post_order_compute (df->postorder, loop);
1430 loop_inverted_post_order_compute (&df->postorder_inverted, loop);
1431 gcc_assert ((unsigned) df->n_blocks == loop->num_nodes);
1432 gcc_assert (df->postorder_inverted.length () == loop->num_nodes);
1434 bitmap blocks = BITMAP_ALLOC (&df_bitmap_obstack);
1435 for (int i = 0; i < df->n_blocks; ++i)
1436 bitmap_set_bit (blocks, df->postorder[i]);
1437 df_set_blocks (blocks);
1438 BITMAP_FREE (blocks);
1444 /* Return the number of basic blocks from the last call to df_analyze. */
1447 df_get_n_blocks (enum df_flow_dir dir)
1449 gcc_assert (dir != DF_NONE);
1451 if (dir == DF_FORWARD)
1453 gcc_assert (df->postorder_inverted.length ());
1454 return df->postorder_inverted.length ();
1457 gcc_assert (df->postorder);
1458 return df->n_blocks;
1462 /* Return a pointer to the array of basic blocks in the reverse postorder.
1463 Depending on the direction of the dataflow problem,
1464 it returns either the usual reverse postorder array
1465 or the reverse postorder of inverted traversal. */
1467 df_get_postorder (enum df_flow_dir dir)
1469 gcc_assert (dir != DF_NONE);
1471 if (dir == DF_FORWARD)
1473 gcc_assert (df->postorder_inverted.length ());
1474 return df->postorder_inverted.address ();
1476 gcc_assert (df->postorder);
1477 return df->postorder;
1480 static struct df_problem user_problem;
1481 static struct dataflow user_dflow;
1483 /* Interface for calling iterative dataflow with user defined
1484 confluence and transfer functions. All that is necessary is to
1485 supply DIR, a direction, CONF_FUN_0, a confluence function for
1486 blocks with no logical preds (or NULL), CONF_FUN_N, the normal
1487 confluence function, TRANS_FUN, the basic block transfer function,
1488 and BLOCKS, the set of blocks to examine, POSTORDER the blocks in
1489 postorder, and N_BLOCKS, the number of blocks in POSTORDER. */
1492 df_simple_dataflow (enum df_flow_dir dir,
1493 df_init_function init_fun,
1494 df_confluence_function_0 con_fun_0,
1495 df_confluence_function_n con_fun_n,
1496 df_transfer_function trans_fun,
1497 bitmap blocks, int * postorder, int n_blocks)
1499 memset (&user_problem, 0, sizeof (struct df_problem));
1500 user_problem.dir = dir;
1501 user_problem.init_fun = init_fun;
1502 user_problem.con_fun_0 = con_fun_0;
1503 user_problem.con_fun_n = con_fun_n;
1504 user_problem.trans_fun = trans_fun;
1505 user_dflow.problem = &user_problem;
1506 df_worklist_dataflow (&user_dflow, blocks, postorder, n_blocks);
1511 /*----------------------------------------------------------------------------
1512 Functions to support limited incremental change.
1513 ----------------------------------------------------------------------------*/
1516 /* Get basic block info. */
1519 df_get_bb_info (struct dataflow *dflow, unsigned int index)
1521 if (dflow->block_info == NULL)
1523 if (index >= dflow->block_info_size)
1525 return (void *)((char *)dflow->block_info
1526 + index * dflow->problem->block_info_elt_size);
1530 /* Set basic block info. */
1533 df_set_bb_info (struct dataflow *dflow, unsigned int index,
1536 gcc_assert (dflow->block_info);
1537 memcpy ((char *)dflow->block_info
1538 + index * dflow->problem->block_info_elt_size,
1539 bb_info, dflow->problem->block_info_elt_size);
1543 /* Clear basic block info. */
1546 df_clear_bb_info (struct dataflow *dflow, unsigned int index)
1548 gcc_assert (dflow->block_info);
1549 gcc_assert (dflow->block_info_size > index);
1550 memset ((char *)dflow->block_info
1551 + index * dflow->problem->block_info_elt_size,
1552 0, dflow->problem->block_info_elt_size);
1556 /* Mark the solutions as being out of date. */
1559 df_mark_solutions_dirty (void)
1564 for (p = 1; p < df->num_problems_defined; p++)
1565 df->problems_in_order[p]->solutions_dirty = true;
1570 /* Return true if BB needs it's transfer functions recomputed. */
1573 df_get_bb_dirty (basic_block bb)
1575 return bitmap_bit_p ((df_live
1576 ? df_live : df_lr)->out_of_date_transfer_functions,
1581 /* Mark BB as needing it's transfer functions as being out of
1585 df_set_bb_dirty (basic_block bb)
1587 bb->flags |= BB_MODIFIED;
1591 for (p = 1; p < df->num_problems_defined; p++)
1593 struct dataflow *dflow = df->problems_in_order[p];
1594 if (dflow->out_of_date_transfer_functions)
1595 bitmap_set_bit (dflow->out_of_date_transfer_functions, bb->index);
1597 df_mark_solutions_dirty ();
1602 /* Grow the bb_info array. */
1605 df_grow_bb_info (struct dataflow *dflow)
1607 unsigned int new_size = last_basic_block_for_fn (cfun) + 1;
1608 if (dflow->block_info_size < new_size)
1610 new_size += new_size / 4;
1612 = (void *)XRESIZEVEC (char, (char *)dflow->block_info,
1614 * dflow->problem->block_info_elt_size);
1615 memset ((char *)dflow->block_info
1616 + dflow->block_info_size
1617 * dflow->problem->block_info_elt_size,
1619 (new_size - dflow->block_info_size)
1620 * dflow->problem->block_info_elt_size);
1621 dflow->block_info_size = new_size;
1626 /* Clear the dirty bits. This is called from places that delete
1629 df_clear_bb_dirty (basic_block bb)
1632 for (p = 1; p < df->num_problems_defined; p++)
1634 struct dataflow *dflow = df->problems_in_order[p];
1635 if (dflow->out_of_date_transfer_functions)
1636 bitmap_clear_bit (dflow->out_of_date_transfer_functions, bb->index);
1640 /* Called from the rtl_compact_blocks to reorganize the problems basic
1644 df_compact_blocks (void)
1648 void *problem_temps;
1650 auto_bitmap tmp (&df_bitmap_obstack);
1651 for (p = 0; p < df->num_problems_defined; p++)
1653 struct dataflow *dflow = df->problems_in_order[p];
1655 /* Need to reorganize the out_of_date_transfer_functions for the
1657 if (dflow->out_of_date_transfer_functions)
1659 bitmap_copy (tmp, dflow->out_of_date_transfer_functions);
1660 bitmap_clear (dflow->out_of_date_transfer_functions);
1661 if (bitmap_bit_p (tmp, ENTRY_BLOCK))
1662 bitmap_set_bit (dflow->out_of_date_transfer_functions, ENTRY_BLOCK);
1663 if (bitmap_bit_p (tmp, EXIT_BLOCK))
1664 bitmap_set_bit (dflow->out_of_date_transfer_functions, EXIT_BLOCK);
1666 i = NUM_FIXED_BLOCKS;
1667 FOR_EACH_BB_FN (bb, cfun)
1669 if (bitmap_bit_p (tmp, bb->index))
1670 bitmap_set_bit (dflow->out_of_date_transfer_functions, i);
1675 /* Now shuffle the block info for the problem. */
1676 if (dflow->problem->free_bb_fun)
1678 int size = (last_basic_block_for_fn (cfun)
1679 * dflow->problem->block_info_elt_size);
1680 problem_temps = XNEWVAR (char, size);
1681 df_grow_bb_info (dflow);
1682 memcpy (problem_temps, dflow->block_info, size);
1684 /* Copy the bb info from the problem tmps to the proper
1685 place in the block_info vector. Null out the copied
1686 item. The entry and exit blocks never move. */
1687 i = NUM_FIXED_BLOCKS;
1688 FOR_EACH_BB_FN (bb, cfun)
1690 df_set_bb_info (dflow, i,
1691 (char *)problem_temps
1692 + bb->index * dflow->problem->block_info_elt_size);
1695 memset ((char *)dflow->block_info
1696 + i * dflow->problem->block_info_elt_size, 0,
1697 (last_basic_block_for_fn (cfun) - i)
1698 * dflow->problem->block_info_elt_size);
1699 free (problem_temps);
1703 /* Shuffle the bits in the basic_block indexed arrays. */
1705 if (df->blocks_to_analyze)
1707 if (bitmap_bit_p (tmp, ENTRY_BLOCK))
1708 bitmap_set_bit (df->blocks_to_analyze, ENTRY_BLOCK);
1709 if (bitmap_bit_p (tmp, EXIT_BLOCK))
1710 bitmap_set_bit (df->blocks_to_analyze, EXIT_BLOCK);
1711 bitmap_copy (tmp, df->blocks_to_analyze);
1712 bitmap_clear (df->blocks_to_analyze);
1713 i = NUM_FIXED_BLOCKS;
1714 FOR_EACH_BB_FN (bb, cfun)
1716 if (bitmap_bit_p (tmp, bb->index))
1717 bitmap_set_bit (df->blocks_to_analyze, i);
1722 i = NUM_FIXED_BLOCKS;
1723 FOR_EACH_BB_FN (bb, cfun)
1725 SET_BASIC_BLOCK_FOR_FN (cfun, i, bb);
1730 gcc_assert (i == n_basic_blocks_for_fn (cfun));
1732 for (; i < last_basic_block_for_fn (cfun); i++)
1733 SET_BASIC_BLOCK_FOR_FN (cfun, i, NULL);
1736 if (!df_lr->solutions_dirty)
1737 df_set_clean_cfg ();
1742 /* Shove NEW_BLOCK in at OLD_INDEX. Called from ifcvt to hack a
1743 block. There is no excuse for people to do this kind of thing. */
1746 df_bb_replace (int old_index, basic_block new_block)
1748 int new_block_index = new_block->index;
1752 fprintf (dump_file, "shoving block %d into %d\n", new_block_index, old_index);
1755 gcc_assert (BASIC_BLOCK_FOR_FN (cfun, old_index) == NULL);
1757 for (p = 0; p < df->num_problems_defined; p++)
1759 struct dataflow *dflow = df->problems_in_order[p];
1760 if (dflow->block_info)
1762 df_grow_bb_info (dflow);
1763 df_set_bb_info (dflow, old_index,
1764 df_get_bb_info (dflow, new_block_index));
1768 df_clear_bb_dirty (new_block);
1769 SET_BASIC_BLOCK_FOR_FN (cfun, old_index, new_block);
1770 new_block->index = old_index;
1771 df_set_bb_dirty (BASIC_BLOCK_FOR_FN (cfun, old_index));
1772 SET_BASIC_BLOCK_FOR_FN (cfun, new_block_index, NULL);
1776 /* Free all of the per basic block dataflow from all of the problems.
1777 This is typically called before a basic block is deleted and the
1778 problem will be reanalyzed. */
1781 df_bb_delete (int bb_index)
1783 basic_block bb = BASIC_BLOCK_FOR_FN (cfun, bb_index);
1789 for (i = 0; i < df->num_problems_defined; i++)
1791 struct dataflow *dflow = df->problems_in_order[i];
1792 if (dflow->problem->free_bb_fun)
1794 void *bb_info = df_get_bb_info (dflow, bb_index);
1797 dflow->problem->free_bb_fun (bb, bb_info);
1798 df_clear_bb_info (dflow, bb_index);
1802 df_clear_bb_dirty (bb);
1803 df_mark_solutions_dirty ();
1807 /* Verify that there is a place for everything and everything is in
1808 its place. This is too expensive to run after every pass in the
1809 mainline. However this is an excellent debugging tool if the
1810 dataflow information is not being updated properly. You can just
1811 sprinkle calls in until you find the place that is changing an
1812 underlying structure without calling the proper updating
1819 #ifdef ENABLE_DF_CHECKING
1820 df_lr_verify_transfer_functions ();
1822 df_live_verify_transfer_functions ();
1824 df->changeable_flags &= ~DF_VERIFY_SCHEDULED;
1829 /* Compute an array of ints that describes the cfg. This can be used
1830 to discover places where the cfg is modified by the appropriate
1831 calls have not been made to the keep df informed. The internals of
1832 this are unexciting, the key is that two instances of this can be
1833 compared to see if any changes have been made to the cfg. */
1836 df_compute_cfg_image (void)
1839 int size = 2 + (2 * n_basic_blocks_for_fn (cfun));
1843 FOR_ALL_BB_FN (bb, cfun)
1845 size += EDGE_COUNT (bb->succs);
1848 map = XNEWVEC (int, size);
1851 FOR_ALL_BB_FN (bb, cfun)
1856 map[i++] = bb->index;
1857 FOR_EACH_EDGE (e, ei, bb->succs)
1858 map[i++] = e->dest->index;
1865 static int *saved_cfg = NULL;
1868 /* This function compares the saved version of the cfg with the
1869 current cfg and aborts if the two are identical. The function
1870 silently returns if the cfg has been marked as dirty or the two are
1874 df_check_cfg_clean (void)
1881 if (df_lr->solutions_dirty)
1884 if (saved_cfg == NULL)
1887 new_map = df_compute_cfg_image ();
1888 gcc_assert (memcmp (saved_cfg, new_map, saved_cfg[0] * sizeof (int)) == 0);
1893 /* This function builds a cfg fingerprint and squirrels it away in
1897 df_set_clean_cfg (void)
1900 saved_cfg = df_compute_cfg_image ();
1903 #endif /* DF_DEBUG_CFG */
1904 /*----------------------------------------------------------------------------
1905 PUBLIC INTERFACES TO QUERY INFORMATION.
1906 ----------------------------------------------------------------------------*/
1909 /* Return first def of REGNO within BB. */
1912 df_bb_regno_first_def_find (basic_block bb, unsigned int regno)
1917 FOR_BB_INSNS (bb, insn)
1922 FOR_EACH_INSN_DEF (def, insn)
1923 if (DF_REF_REGNO (def) == regno)
1930 /* Return last def of REGNO within BB. */
1933 df_bb_regno_last_def_find (basic_block bb, unsigned int regno)
1938 FOR_BB_INSNS_REVERSE (bb, insn)
1943 FOR_EACH_INSN_DEF (def, insn)
1944 if (DF_REF_REGNO (def) == regno)
1951 /* Finds the reference corresponding to the definition of REG in INSN.
1952 DF is the dataflow object. */
1955 df_find_def (rtx_insn *insn, rtx reg)
1959 if (GET_CODE (reg) == SUBREG)
1960 reg = SUBREG_REG (reg);
1961 gcc_assert (REG_P (reg));
1963 FOR_EACH_INSN_DEF (def, insn)
1964 if (DF_REF_REGNO (def) == REGNO (reg))
1971 /* Return true if REG is defined in INSN, zero otherwise. */
1974 df_reg_defined (rtx_insn *insn, rtx reg)
1976 return df_find_def (insn, reg) != NULL;
1980 /* Finds the reference corresponding to the use of REG in INSN.
1981 DF is the dataflow object. */
1984 df_find_use (rtx_insn *insn, rtx reg)
1988 if (GET_CODE (reg) == SUBREG)
1989 reg = SUBREG_REG (reg);
1990 gcc_assert (REG_P (reg));
1992 df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
1993 FOR_EACH_INSN_INFO_USE (use, insn_info)
1994 if (DF_REF_REGNO (use) == REGNO (reg))
1996 if (df->changeable_flags & DF_EQ_NOTES)
1997 FOR_EACH_INSN_INFO_EQ_USE (use, insn_info)
1998 if (DF_REF_REGNO (use) == REGNO (reg))
2004 /* Return true if REG is referenced in INSN, zero otherwise. */
2007 df_reg_used (rtx_insn *insn, rtx reg)
2009 return df_find_use (insn, reg) != NULL;
2012 /* If REG has a single definition, return its known value, otherwise return
2016 df_find_single_def_src (rtx reg)
2020 /* Don't look through unbounded number of single definition REG copies,
2021 there might be loops for sources with uninitialized variables. */
2022 for (int cnt = 0; cnt < 128; cnt++)
2024 df_ref adef = DF_REG_DEF_CHAIN (REGNO (reg));
2025 if (adef == NULL || DF_REF_NEXT_REG (adef) != NULL
2026 || DF_REF_IS_ARTIFICIAL (adef)
2027 || (DF_REF_FLAGS (adef)
2028 & (DF_REF_PARTIAL | DF_REF_CONDITIONAL)))
2031 rtx set = single_set (DF_REF_INSN (adef));
2032 if (set == NULL || !rtx_equal_p (SET_DEST (set), reg))
2035 rtx note = find_reg_equal_equiv_note (DF_REF_INSN (adef));
2036 if (note && function_invariant_p (XEXP (note, 0)))
2037 return XEXP (note, 0);
2038 src = SET_SRC (set);
2047 if (!function_invariant_p (src))
2054 /*----------------------------------------------------------------------------
2055 Debugging and printing functions.
2056 ----------------------------------------------------------------------------*/
2058 /* Write information about registers and basic blocks into FILE.
2059 This is part of making a debugging dump. */
2062 dump_regset (regset r, FILE *outf)
2065 reg_set_iterator rsi;
2069 fputs (" (nil)", outf);
2073 EXECUTE_IF_SET_IN_REG_SET (r, 0, i, rsi)
2075 fprintf (outf, " %d", i);
2076 if (i < FIRST_PSEUDO_REGISTER)
2077 fprintf (outf, " [%s]",
2082 /* Print a human-readable representation of R on the standard error
2083 stream. This function is designed to be used from within the
2085 extern void debug_regset (regset);
2087 debug_regset (regset r)
2089 dump_regset (r, stderr);
2090 putc ('\n', stderr);
2093 /* Write information about registers and basic blocks into FILE.
2094 This is part of making a debugging dump. */
2097 df_print_regset (FILE *file, const_bitmap r)
2103 fputs (" (nil)", file);
2106 EXECUTE_IF_SET_IN_BITMAP (r, 0, i, bi)
2108 fprintf (file, " %d", i);
2109 if (i < FIRST_PSEUDO_REGISTER)
2110 fprintf (file, " [%s]", reg_names[i]);
2113 fprintf (file, "\n");
2117 /* Write information about registers and basic blocks into FILE. The
2118 bitmap is in the form used by df_byte_lr. This is part of making a
2122 df_print_word_regset (FILE *file, const_bitmap r)
2124 unsigned int max_reg = max_reg_num ();
2127 fputs (" (nil)", file);
2131 for (i = FIRST_PSEUDO_REGISTER; i < max_reg; i++)
2133 bool found = (bitmap_bit_p (r, 2 * i)
2134 || bitmap_bit_p (r, 2 * i + 1));
2138 const char * sep = "";
2139 fprintf (file, " %d", i);
2140 fprintf (file, "(");
2141 for (word = 0; word < 2; word++)
2142 if (bitmap_bit_p (r, 2 * i + word))
2144 fprintf (file, "%s%d", sep, word);
2147 fprintf (file, ")");
2151 fprintf (file, "\n");
2155 /* Dump dataflow info. */
2158 df_dump (FILE *file)
2161 df_dump_start (file);
2163 FOR_ALL_BB_FN (bb, cfun)
2165 df_print_bb_index (bb, file);
2166 df_dump_top (bb, file);
2167 df_dump_bottom (bb, file);
2170 fprintf (file, "\n");
2174 /* Dump dataflow info for df->blocks_to_analyze. */
2177 df_dump_region (FILE *file)
2179 if (df->blocks_to_analyze)
2182 unsigned int bb_index;
2184 fprintf (file, "\n\nstarting region dump\n");
2185 df_dump_start (file);
2187 EXECUTE_IF_SET_IN_BITMAP (df->blocks_to_analyze, 0, bb_index, bi)
2189 basic_block bb = BASIC_BLOCK_FOR_FN (cfun, bb_index);
2190 dump_bb (file, bb, 0, TDF_DETAILS);
2192 fprintf (file, "\n");
2199 /* Dump the introductory information for each problem defined. */
2202 df_dump_start (FILE *file)
2209 fprintf (file, "\n\n%s\n", current_function_name ());
2210 fprintf (file, "\nDataflow summary:\n");
2211 if (df->blocks_to_analyze)
2212 fprintf (file, "def_info->table_size = %d, use_info->table_size = %d\n",
2213 DF_DEFS_TABLE_SIZE (), DF_USES_TABLE_SIZE ());
2215 for (i = 0; i < df->num_problems_defined; i++)
2217 struct dataflow *dflow = df->problems_in_order[i];
2218 if (dflow->computed)
2220 df_dump_problem_function fun = dflow->problem->dump_start_fun;
2228 /* Dump the top or bottom of the block information for BB. */
2230 df_dump_bb_problem_data (basic_block bb, FILE *file, bool top)
2237 for (i = 0; i < df->num_problems_defined; i++)
2239 struct dataflow *dflow = df->problems_in_order[i];
2240 if (dflow->computed)
2242 df_dump_bb_problem_function bbfun;
2245 bbfun = dflow->problem->dump_top_fun;
2247 bbfun = dflow->problem->dump_bottom_fun;
2255 /* Dump the top of the block information for BB. */
2258 df_dump_top (basic_block bb, FILE *file)
2260 df_dump_bb_problem_data (bb, file, /*top=*/true);
2263 /* Dump the bottom of the block information for BB. */
2266 df_dump_bottom (basic_block bb, FILE *file)
2268 df_dump_bb_problem_data (bb, file, /*top=*/false);
2272 /* Dump information about INSN just before or after dumping INSN itself. */
2274 df_dump_insn_problem_data (const rtx_insn *insn, FILE *file, bool top)
2281 for (i = 0; i < df->num_problems_defined; i++)
2283 struct dataflow *dflow = df->problems_in_order[i];
2284 if (dflow->computed)
2286 df_dump_insn_problem_function insnfun;
2289 insnfun = dflow->problem->dump_insn_top_fun;
2291 insnfun = dflow->problem->dump_insn_bottom_fun;
2294 insnfun (insn, file);
2299 /* Dump information about INSN before dumping INSN itself. */
2302 df_dump_insn_top (const rtx_insn *insn, FILE *file)
2304 df_dump_insn_problem_data (insn, file, /*top=*/true);
2307 /* Dump information about INSN after dumping INSN itself. */
2310 df_dump_insn_bottom (const rtx_insn *insn, FILE *file)
2312 df_dump_insn_problem_data (insn, file, /*top=*/false);
2317 df_ref_dump (df_ref ref, FILE *file)
2319 fprintf (file, "%c%d(%d)",
2320 DF_REF_REG_DEF_P (ref)
2322 : (DF_REF_FLAGS (ref) & DF_REF_IN_NOTE) ? 'e' : 'u',
2324 DF_REF_REGNO (ref));
2328 df_refs_chain_dump (df_ref ref, bool follow_chain, FILE *file)
2330 fprintf (file, "{ ");
2331 for (; ref; ref = DF_REF_NEXT_LOC (ref))
2333 df_ref_dump (ref, file);
2335 df_chain_dump (DF_REF_CHAIN (ref), file);
2337 fprintf (file, "}");
2341 /* Dump either a ref-def or reg-use chain. */
2344 df_regs_chain_dump (df_ref ref, FILE *file)
2346 fprintf (file, "{ ");
2349 df_ref_dump (ref, file);
2350 ref = DF_REF_NEXT_REG (ref);
2352 fprintf (file, "}");
2357 df_mws_dump (struct df_mw_hardreg *mws, FILE *file)
2359 for (; mws; mws = DF_MWS_NEXT (mws))
2360 fprintf (file, "mw %c r[%d..%d]\n",
2361 DF_MWS_REG_DEF_P (mws) ? 'd' : 'u',
2362 mws->start_regno, mws->end_regno);
2367 df_insn_uid_debug (unsigned int uid,
2368 bool follow_chain, FILE *file)
2370 fprintf (file, "insn %d luid %d",
2371 uid, DF_INSN_UID_LUID (uid));
2373 if (DF_INSN_UID_DEFS (uid))
2375 fprintf (file, " defs ");
2376 df_refs_chain_dump (DF_INSN_UID_DEFS (uid), follow_chain, file);
2379 if (DF_INSN_UID_USES (uid))
2381 fprintf (file, " uses ");
2382 df_refs_chain_dump (DF_INSN_UID_USES (uid), follow_chain, file);
2385 if (DF_INSN_UID_EQ_USES (uid))
2387 fprintf (file, " eq uses ");
2388 df_refs_chain_dump (DF_INSN_UID_EQ_USES (uid), follow_chain, file);
2391 if (DF_INSN_UID_MWS (uid))
2393 fprintf (file, " mws ");
2394 df_mws_dump (DF_INSN_UID_MWS (uid), file);
2396 fprintf (file, "\n");
2401 df_insn_debug (rtx_insn *insn, bool follow_chain, FILE *file)
2403 df_insn_uid_debug (INSN_UID (insn), follow_chain, file);
2407 df_insn_debug_regno (rtx_insn *insn, FILE *file)
2409 struct df_insn_info *insn_info = DF_INSN_INFO_GET (insn);
2411 fprintf (file, "insn %d bb %d luid %d defs ",
2412 INSN_UID (insn), BLOCK_FOR_INSN (insn)->index,
2413 DF_INSN_INFO_LUID (insn_info));
2414 df_refs_chain_dump (DF_INSN_INFO_DEFS (insn_info), false, file);
2416 fprintf (file, " uses ");
2417 df_refs_chain_dump (DF_INSN_INFO_USES (insn_info), false, file);
2419 fprintf (file, " eq_uses ");
2420 df_refs_chain_dump (DF_INSN_INFO_EQ_USES (insn_info), false, file);
2421 fprintf (file, "\n");
2425 df_regno_debug (unsigned int regno, FILE *file)
2427 fprintf (file, "reg %d defs ", regno);
2428 df_regs_chain_dump (DF_REG_DEF_CHAIN (regno), file);
2429 fprintf (file, " uses ");
2430 df_regs_chain_dump (DF_REG_USE_CHAIN (regno), file);
2431 fprintf (file, " eq_uses ");
2432 df_regs_chain_dump (DF_REG_EQ_USE_CHAIN (regno), file);
2433 fprintf (file, "\n");
2438 df_ref_debug (df_ref ref, FILE *file)
2440 fprintf (file, "%c%d ",
2441 DF_REF_REG_DEF_P (ref) ? 'd' : 'u',
2443 fprintf (file, "reg %d bb %d insn %d flag %#x type %#x ",
2446 DF_REF_IS_ARTIFICIAL (ref) ? -1 : DF_REF_INSN_UID (ref),
2449 if (DF_REF_LOC (ref))
2451 if (flag_dump_noaddr)
2452 fprintf (file, "loc #(#) chain ");
2454 fprintf (file, "loc %p(%p) chain ", (void *)DF_REF_LOC (ref),
2455 (void *)*DF_REF_LOC (ref));
2458 fprintf (file, "chain ");
2459 df_chain_dump (DF_REF_CHAIN (ref), file);
2460 fprintf (file, "\n");
2463 /* Functions for debugging from GDB. */
2466 debug_df_insn (rtx_insn *insn)
2468 df_insn_debug (insn, true, stderr);
2474 debug_df_reg (rtx reg)
2476 df_regno_debug (REGNO (reg), stderr);
2481 debug_df_regno (unsigned int regno)
2483 df_regno_debug (regno, stderr);
2488 debug_df_ref (df_ref ref)
2490 df_ref_debug (ref, stderr);
2495 debug_df_defno (unsigned int defno)
2497 df_ref_debug (DF_DEFS_GET (defno), stderr);
2502 debug_df_useno (unsigned int defno)
2504 df_ref_debug (DF_USES_GET (defno), stderr);
2509 debug_df_chain (struct df_link *link)
2511 df_chain_dump (link, stderr);
2512 fputc ('\n', stderr);