Line data Source code
1 : /* Header file for the value range relational processing.
2 : Copyright (C) 2020-2026 Free Software Foundation, Inc.
3 : Contributed by Andrew MacLeod <amacleod@redhat.com>
4 :
5 : This file is part of GCC.
6 :
7 : GCC is free software; you can redistribute it and/or modify it under
8 : the terms of the GNU General Public License as published by the Free
9 : Software Foundation; either version 3, or (at your option) any later
10 : version.
11 :
12 : GCC is distributed in the hope that it will be useful, but WITHOUT ANY
13 : WARRANTY; without even the implied warranty of MERCHANTABILITY or
14 : FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License
15 : for more details.
16 :
17 : You should have received a copy of the GNU General Public License
18 : along with GCC; see the file COPYING3. If not see
19 : <http://www.gnu.org/licenses/>. */
20 :
21 : #ifndef GCC_VALUE_RELATION_H
22 : #define GCC_VALUE_RELATION_H
23 :
24 :
25 : // This file provides access to a relation oracle which can be used to
26 : // maintain and query relations and equivalences between SSA_NAMES.
27 : //
28 : // The general range_query object provided in value-query.h provides
29 : // access to an oracle, if one is available, via the oracle() method.
30 : // There are also a couple of access routines provided, which even if there is
31 : // no oracle, will return the default VREL_VARYING no relation.
32 : //
33 : // Typically, when a ranger object is active, there will be an oracle, and
34 : // any information available can be directly queried. Ranger also sets and
35 : // utilizes the relation information to enhance it's range calculations, this
36 : // is totally transparent to the client, and they are free to make queries.
37 : //
38 : // relation_kind is a new enum which represents the different relations,
39 : // often with a direct mapping to tree codes. ie VREL_EQ is equivalent to
40 : // EQ_EXPR.
41 : //
42 : // A query is made requesting the relation between SSA1 and SSA@ in a basic
43 : // block, or on an edge, the possible return values are:
44 : //
45 : // VREL_EQ, VREL_NE, VREL_LT, VREL_LE, VREL_GT, and VREL_GE mean the same.
46 : // VREL_VARYING : No relation between the 2 names.
47 : // VREL_UNDEFINED : Impossible relation (ie, A < B && A > B)
48 : //
49 : // The oracle maintains VREL_EQ relations with equivalency sets, so if a
50 : // relation comes back VREL_EQ, it is also possible to query the set of
51 : // equivalencies. These are basically bitmaps over ssa_names. An iterator is
52 : // provided later for this activity.
53 : //
54 : // Relations are maintained via the dominance trees and are optimized assuming
55 : // they are registered in dominance order. When a new relation is added, it
56 : // is intersected with whatever existing relation exists in the dominance tree
57 : // and registered at the specified block.
58 :
59 :
60 : // These codes are arranged such that VREL_VARYING is the first code, and all
61 : // the rest are contiguous.
62 :
63 : typedef enum relation_kind_t
64 : {
65 : VREL_VARYING = 0, // No known relation, AKA varying.
66 : VREL_UNDEFINED, // Impossible relation, ie (r1 < r2) && (r2 > r1)
67 : VREL_LT, // r1 < r2
68 : VREL_LE, // r1 <= r2
69 : VREL_GT, // r1 > r2
70 : VREL_GE, // r1 >= r2
71 : VREL_EQ, // r1 == r2
72 : VREL_NE, // r1 != r2
73 : VREL_PE8, // 8 bit partial equivalency
74 : VREL_PE16, // 16 bit partial equivalency
75 : VREL_PE32, // 32 bit partial equivalency
76 : VREL_PE64, // 64 bit partial equivalency
77 : VREL_LAST // terminate, not a real relation.
78 : } relation_kind;
79 :
80 : // General relation kind transformations.
81 : relation_kind relation_union (relation_kind r1, relation_kind r2);
82 : relation_kind relation_intersect (relation_kind r1, relation_kind r2);
83 : relation_kind relation_negate (relation_kind r);
84 : relation_kind relation_swap (relation_kind r);
85 5178829 : inline bool relation_lt_le_gt_ge_p (relation_kind r)
86 5178829 : { return (r >= VREL_LT && r <= VREL_GE); }
87 210870368 : inline bool relation_partial_equiv_p (relation_kind r)
88 123692941 : { return (r >= VREL_PE8 && r <= VREL_PE64); }
89 183625207 : inline bool relation_equiv_p (relation_kind r)
90 183625219 : { return r == VREL_EQ || relation_partial_equiv_p (r); }
91 :
92 : void print_relation (FILE *f, relation_kind rel);
93 :
94 : // Adjust range as an equivalence.
95 : void adjust_equivalence_range (vrange &range);
96 :
97 : class relation_oracle
98 : {
99 : public:
100 59134804 : relation_oracle () { m_lhs_equiv_set_p = NULL; }
101 59427830 : virtual ~relation_oracle () { }
102 :
103 : // register a relation between 2 ssa names.
104 : bool record (gimple *, relation_kind, tree, tree);
105 : bool record (edge, relation_kind, tree, tree);
106 1064567 : virtual bool record (basic_block, relation_kind, tree, tree) { return false; }
107 :
108 : // Query if there is any relation between SSA1 and SSA2.
109 : relation_kind query (gimple *s, tree ssa1, tree ssa2);
110 : relation_kind query (edge e, tree ssa1, tree ssa2);
111 14587788 : virtual relation_kind query (basic_block, tree, tree) { return VREL_VARYING; }
112 :
113 : // Remove relations for an SSA_NAME
114 7879420 : virtual void clear (tree) { }
115 :
116 0 : virtual void dump (FILE *, basic_block) const { }
117 0 : virtual void dump (FILE *) const { }
118 : void debug () const;
119 : protected:
120 : friend class equiv_relation_iterator;
121 : friend class block_relation_iterator;
122 0 : virtual class relation_chain *next_relation (basic_block,
123 : relation_chain *,
124 : tree) const
125 0 : { return NULL; }
126 : // Return equivalency set for an SSA name in a basic block.
127 1 : virtual const_bitmap equiv_set (tree, basic_block) { return NULL; }
128 : // Return partial equivalency record for an SSA name.
129 1 : virtual const class pe_slice *partial_equiv_set (tree) { return NULL; }
130 : void valid_equivs (bitmap b, const_bitmap equivs, basic_block bb);
131 : // Query for a relation between two equivalency sets in a basic block.
132 0 : virtual relation_kind query (basic_block, const_bitmap, const_bitmap)
133 0 : { return VREL_VARYING; }
134 : friend class path_oracle;
135 : // Used to Avoid registering multiple eqiuvalences from the same statement.
136 : bitmap m_lhs_equiv_set_p;
137 : };
138 :
139 : // Instance with no storage used for default queries with no active oracle.
140 : extern relation_oracle default_relation_oracle;
141 :
142 : // This class represents an equivalency set, and contains a link to the next
143 : // one in the list to be searched.
144 :
145 : class equiv_chain
146 : {
147 : public:
148 : bitmap m_names; // ssa-names in equiv set.
149 : basic_block m_bb; // Block this belongs to
150 : equiv_chain *m_next; // Next in block list.
151 : void dump (FILE *f) const; // Show names in this list.
152 : equiv_chain *find (unsigned ssa);
153 : };
154 :
155 : class pe_slice
156 : {
157 : public:
158 : tree ssa_base; // Slice of this name.
159 : relation_kind code; // bits that are equivalent.
160 : bitmap members; // Other members in the partial equivalency.
161 : };
162 :
163 : // The equivalency oracle maintains equivalencies using the dominator tree.
164 : // Equivalencies apply to an entire basic block. Equivalencies on edges
165 : // can be represented only on edges whose destination is a single-pred block,
166 : // and the equivalence is simply applied to that successor block.
167 :
168 : class equiv_oracle : public relation_oracle
169 : {
170 : public:
171 : equiv_oracle ();
172 : ~equiv_oracle ();
173 :
174 : const_bitmap equiv_set (tree ssa, basic_block bb) final override;
175 : bool record (basic_block bb, relation_kind k, tree ssa1, tree ssa2) override;
176 :
177 : relation_kind partial_equiv (tree ssa1, tree ssa2, tree *base = NULL) const;
178 : relation_kind query (basic_block, tree, tree) override;
179 : relation_kind query (basic_block, const_bitmap, const_bitmap) override;
180 :
181 : virtual void clear (tree name);
182 : void dump (FILE *f, basic_block bb) const override;
183 : void dump (FILE *f) const override;
184 :
185 : protected:
186 : bool add_partial_equiv (relation_kind, tree, tree);
187 : const pe_slice *partial_equiv_set (tree name) final override;
188 86382160 : inline bool has_equiv_p (unsigned v) { return bitmap_bit_p (m_equiv_set, v); }
189 : bitmap_obstack m_bitmaps;
190 : struct obstack m_chain_obstack;
191 : private:
192 : bitmap m_equiv_set; // Index by ssa-name. true if an equivalence exists.
193 : vec <equiv_chain *> m_equiv; // Index by BB. list of equivalences.
194 : class name_info
195 : {
196 : public:
197 : bitmap m_self_equiv; // Self equivalency set.
198 : bitmap m_block_list; // BB's name occurs in equivalencies.
199 : };
200 : vec <name_info> m_name_info; // Index by ssa-name.
201 : vec <pe_slice> m_partial; // Partial equivalencies.
202 :
203 : void limit_check (basic_block bb = NULL);
204 : equiv_chain *find_equiv_block (unsigned ssa, int bb) const;
205 : equiv_chain *find_equiv_dom (tree name, basic_block bb) const;
206 :
207 : bitmap register_equiv (basic_block bb, unsigned v, equiv_chain *equiv_1);
208 : bitmap register_equiv (basic_block bb, equiv_chain *equiv_1,
209 : equiv_chain *equiv_2);
210 :
211 : void register_equiv_block (unsigned v, unsigned bbi);
212 : void register_equiv_block (const_bitmap equiv, basic_block bb);
213 :
214 : void register_initial_def (tree ssa);
215 : void add_equiv_to_block (basic_block bb, bitmap equiv);
216 : };
217 :
218 : // Summary block header for relations.
219 :
220 : class relation_chain_head
221 : {
222 : public:
223 : bitmap m_names; // ssa_names with relations in this block.
224 : class relation_chain *m_head; // List of relations in block.
225 : int m_num_relations; // Number of relations in block.
226 : relation_kind find_relation (const_bitmap b1, const_bitmap b2) const;
227 : void clear (tree name);
228 : };
229 :
230 : // A relation oracle maintains a set of relations between ssa_names using the
231 : // dominator tree structures. Equivalencies are considered a subset of
232 : // a general relation and maintained by an equivalence oracle by transparently
233 : // passing any EQ_EXPR relations to it.
234 : // Relations are handled at the basic block level. All relations apply to
235 : // an entire block, and are thus kept in a summary index by block.
236 : // Similar to the equivalence oracle, edges are handled by applying the
237 : // relation to the destination block of the edge, but ONLY if that block
238 : // has a single successor. For now.
239 :
240 : class dom_oracle : public equiv_oracle
241 : {
242 : public:
243 : dom_oracle (bool do_trans_p = true);
244 : ~dom_oracle ();
245 :
246 : bool record (basic_block bb, relation_kind k, tree op1, tree op2)
247 : final override;
248 :
249 : relation_kind query (basic_block bb, tree ssa1, tree ssa2) final override;
250 : relation_kind query (basic_block bb, const_bitmap b1, const_bitmap b2)
251 : final override;
252 :
253 : virtual void clear (tree name);
254 :
255 : void dump (FILE *f, basic_block bb) const final override;
256 : void dump (FILE *f) const final override;
257 : protected:
258 : virtual relation_chain *next_relation (basic_block, relation_chain *,
259 : tree) const override;
260 : bool m_do_trans_p;
261 : bitmap m_tmp, m_tmp2;
262 : bitmap m_relation_set; // Index by ssa-name. True if a relation exists
263 : vec <relation_chain_head> m_relations; // Index by BB, list of relations.
264 : vec <bitmap> m_block_list; // Index by ssa-name. Blocks with relations.
265 : relation_kind find_relation_block (unsigned bb, const_bitmap b1,
266 : const_bitmap b2) const;
267 : relation_kind find_relation_block (int bb, tree ssa1, tree ssa2,
268 : relation_chain **obj = NULL) const;
269 : relation_kind find_relation_dom (basic_block bb, tree ssa1, tree ssa2) const;
270 : relation_chain *create_relation_in_bb (basic_block bb, relation_kind k,
271 : tree op1, tree op2);
272 : relation_chain *search_and_merge_relation (basic_block bb, relation_kind k,
273 : tree op1, tree op2);
274 : void record_relation_block (unsigned v, unsigned bbi);
275 : void register_transitives (basic_block, const class value_relation &);
276 : relation_kind recomputed_relation (basic_block, edge, tree, tree) const;
277 : };
278 :
279 : // A path_oracle implements relations in a list. The only sense of ordering
280 : // is the latest registered relation is the first found during a search.
281 : // It can be constructed with an optional "root" oracle which will be used
282 : // to look up any relations not found in the list.
283 : // This allows the client to walk paths starting at some block and register
284 : // and query relations along that path, ignoring other edges.
285 : //
286 : // For registering a relation, a query if made of the root oracle if there is
287 : // any known relationship at block BB, and it is combined with this new
288 : // relation and entered in the list.
289 : //
290 : // Queries are resolved by looking first in the list, and only if nothing is
291 : // found is the root oracle queried at block BB.
292 : //
293 : // reset_path is used to clear all locally registered paths to initial state.
294 :
295 : class path_oracle : public relation_oracle
296 : {
297 : public:
298 : path_oracle (relation_oracle *oracle = NULL);
299 : ~path_oracle ();
300 : const_bitmap equiv_set (tree, basic_block) final override;
301 : bool record (basic_block, relation_kind, tree, tree) final override;
302 : void killing_def (tree);
303 : relation_kind query (basic_block, tree, tree) final override;
304 : relation_kind query (basic_block, const_bitmap, const_bitmap) final override;
305 : void reset_path (relation_oracle *oracle = NULL);
306 56495554 : void set_root_oracle (relation_oracle *oracle) { m_root = oracle; }
307 :
308 : virtual void clear (tree name);
309 :
310 : void dump (FILE *, basic_block) const final override;
311 : void dump (FILE *) const final override;
312 : private:
313 : bool register_equiv (basic_block bb, tree ssa1, tree ssa2);
314 : equiv_chain m_equiv;
315 : relation_chain_head m_relations;
316 : relation_oracle *m_root;
317 : bitmap m_killed_defs;
318 :
319 : bitmap_obstack m_bitmaps;
320 : struct obstack m_chain_obstack;
321 : };
322 :
323 : // Used to assist with iterating over the equivalence list.
324 : class equiv_relation_iterator {
325 : public:
326 : equiv_relation_iterator (relation_oracle *oracle, basic_block bb, tree name,
327 : bool full = true, bool partial = false);
328 : void next ();
329 : tree get_name (relation_kind *rel = NULL);
330 : protected:
331 : relation_oracle *m_oracle;
332 : const_bitmap m_bm;
333 : const pe_slice *m_pe;
334 : bitmap_iterator m_bi;
335 : unsigned m_y;
336 : tree m_name;
337 : };
338 :
339 : #define FOR_EACH_EQUIVALENCE(oracle, bb, name, equiv_name) \
340 : for (equiv_relation_iterator iter (oracle, bb, name, true, false); \
341 : ((equiv_name) = iter.get_name ()); \
342 : iter.next ())
343 :
344 : #define FOR_EACH_PARTIAL_EQUIV(oracle, bb, name, equiv_name, equiv_rel) \
345 : for (equiv_relation_iterator iter (oracle, bb, name, false, true); \
346 : ((equiv_name) = iter.get_name (&equiv_rel)); \
347 : iter.next ())
348 :
349 : #define FOR_EACH_PARTIAL_AND_FULL_EQUIV(oracle, bb, name, equiv_name, \
350 : equiv_rel) \
351 : for (equiv_relation_iterator iter (oracle, bb, name, true, true); \
352 : ((equiv_name) = iter.get_name (&equiv_rel)); \
353 : iter.next ())
354 :
355 : // -----------------------------------------------------------------------
356 :
357 : // Range-ops deals with a LHS and 2 operands. A relation trio is a set of
358 : // 3 potential relations packed into a single unsigned value.
359 : // 1 - LHS relation OP1
360 : // 2 - LHS relation OP2
361 : // 3 - OP1 relation OP2
362 : // VREL_VARYING is a value of 0, and is the default for each position.
363 : class relation_trio
364 : {
365 : public:
366 : relation_trio ();
367 : relation_trio (relation_kind lhs_op1, relation_kind lhs_op2,
368 : relation_kind op1_op2);
369 : relation_kind lhs_op1 ();
370 : relation_kind lhs_op2 ();
371 : relation_kind op1_op2 ();
372 : relation_trio swap_op1_op2 ();
373 :
374 : static relation_trio lhs_op1 (relation_kind k);
375 : static relation_trio lhs_op2 (relation_kind k);
376 : static relation_trio op1_op2 (relation_kind k);
377 :
378 : protected:
379 : unsigned m_val;
380 : };
381 :
382 : // Default VREL_VARYING for all 3 relations.
383 : #define TRIO_VARYING relation_trio ()
384 :
385 : #define TRIO_SHIFT 4
386 : #define TRIO_MASK 0x000F
387 :
388 : // These 3 classes are shortcuts for when a caller has a single relation to
389 : // pass as a trio, it can simply construct the appropriate one. The other
390 : // unspecified relations will be VREL_VARYING.
391 :
392 270224219 : inline relation_trio::relation_trio ()
393 : {
394 270224219 : STATIC_ASSERT (VREL_LAST <= (1 << TRIO_SHIFT));
395 270224219 : m_val = 0;
396 : }
397 :
398 242057095 : inline relation_trio::relation_trio (relation_kind lhs_op1,
399 : relation_kind lhs_op2,
400 : relation_kind op1_op2)
401 : {
402 242057095 : STATIC_ASSERT (VREL_LAST <= (1 << TRIO_SHIFT));
403 242057095 : unsigned i1 = (unsigned) lhs_op1;
404 242057095 : unsigned i2 = ((unsigned) lhs_op2) << TRIO_SHIFT;
405 242057095 : unsigned i3 = ((unsigned) op1_op2) << (TRIO_SHIFT * 2);
406 241932440 : m_val = i1 | i2 | i3;
407 : }
408 :
409 : inline relation_trio
410 738958 : relation_trio::lhs_op1 (relation_kind k)
411 : {
412 738958 : return relation_trio (k, VREL_VARYING, VREL_VARYING);
413 : }
414 : inline relation_trio
415 608275 : relation_trio::lhs_op2 (relation_kind k)
416 : {
417 608275 : return relation_trio (VREL_VARYING, k, VREL_VARYING);
418 : }
419 : inline relation_trio
420 176260784 : relation_trio::op1_op2 (relation_kind k)
421 : {
422 176260784 : return relation_trio (VREL_VARYING, VREL_VARYING, k);
423 : }
424 :
425 : inline relation_kind
426 21177992 : relation_trio::lhs_op1 ()
427 : {
428 11779795 : return (relation_kind) (m_val & TRIO_MASK);
429 : }
430 :
431 : inline relation_kind
432 9663453 : relation_trio::lhs_op2 ()
433 : {
434 9804053 : return (relation_kind) ((m_val >> TRIO_SHIFT) & TRIO_MASK);
435 : }
436 :
437 : inline relation_kind
438 326107347 : relation_trio::op1_op2 ()
439 : {
440 316443895 : return (relation_kind) ((m_val >> (TRIO_SHIFT * 2)) & TRIO_MASK);
441 : }
442 :
443 : inline relation_trio
444 9663452 : relation_trio::swap_op1_op2 ()
445 : {
446 9663452 : return relation_trio (lhs_op2 (), lhs_op1 (), relation_swap (op1_op2 ()));
447 : }
448 :
449 : // -----------------------------------------------------------------------
450 :
451 : // The value-relation class is used to encapsulate the representation of an
452 : // individual relation between 2 ssa-names, and to facilitate operating on
453 : // the relation.
454 :
455 : class value_relation
456 : {
457 : public:
458 : value_relation ();
459 : value_relation (relation_kind kind, tree n1, tree n2);
460 : void set_relation (relation_kind kind, tree n1, tree n2);
461 :
462 30562687 : inline relation_kind kind () const { return related; }
463 142657310 : inline tree op1 () const { return name1; }
464 139697512 : inline tree op2 () const { return name2; }
465 :
466 : relation_trio create_trio (tree lhs, tree op1, tree op2);
467 : bool union_ (value_relation &p);
468 : bool intersect (value_relation &p);
469 : void swap ();
470 : bool apply_transitive (const value_relation &rel);
471 :
472 : void dump (FILE *f) const;
473 : private:
474 : relation_kind related;
475 : tree name1, name2;
476 : };
477 :
478 : // Set relation R between ssa_name N1 and N2.
479 :
480 : inline void
481 98042726 : value_relation::set_relation (relation_kind r, tree n1, tree n2)
482 : {
483 98042726 : gcc_checking_assert (TREE_CODE (n1) == SSA_NAME
484 : && TREE_CODE (n2) == SSA_NAME);
485 98042726 : related = r;
486 98042726 : name1 = n1;
487 98042726 : name2 = n2;
488 98042726 : }
489 :
490 : // Default constructor.
491 :
492 : inline
493 127651892 : value_relation::value_relation ()
494 : {
495 127651892 : related = VREL_VARYING;
496 127651892 : name1 = NULL_TREE;
497 127651892 : name2 = NULL_TREE;
498 : }
499 :
500 : // Constructor for relation R between SSA version N1 and N2.
501 :
502 : inline
503 16374349 : value_relation::value_relation (relation_kind kind, tree n1, tree n2)
504 : {
505 16374349 : set_relation (kind, n1, n2);
506 : }
507 :
508 :
509 : class block_relation_iterator {
510 : public:
511 : block_relation_iterator (const relation_oracle *oracle, basic_block bb,
512 : value_relation &, tree name = NULL);
513 : void get_next_relation (value_relation &vr);
514 : const relation_oracle *m_oracle;
515 : basic_block m_bb;
516 : relation_chain *m_ptr;
517 : bool m_done;
518 : tree m_name;
519 : };
520 :
521 : #define FOR_EACH_RELATION_BB(oracle, bb, vr) \
522 : for (block_relation_iterator iter (oracle, bb, vr); \
523 : !iter.m_done; \
524 : iter.get_next_relation (vr))
525 :
526 : #define FOR_EACH_RELATION_NAME(oracle, bb, name, vr) \
527 : for (block_relation_iterator iter (oracle, bb, vr, name); \
528 : !iter.m_done; \
529 : iter.get_next_relation (vr))
530 :
531 :
532 : // Return the number of bits associated with partial equivalency T.
533 : // Return 0 if this is not a supported partial equivalency relation.
534 :
535 : inline int
536 18024564 : pe_to_bits (relation_kind t)
537 : {
538 18024564 : switch (t)
539 : {
540 : case VREL_PE8:
541 : return 8;
542 : case VREL_PE16:
543 : return 16;
544 : case VREL_PE32:
545 : return 32;
546 : case VREL_PE64:
547 : return 64;
548 : default:
549 : return 0;
550 : }
551 : }
552 :
553 : // Return the partial equivalency code associated with the number of BITS.
554 : // return VREL_VARYING if there is no exact match.
555 :
556 : inline relation_kind
557 39039594 : bits_to_pe (int bits)
558 : {
559 39039594 : switch (bits)
560 : {
561 : case 8:
562 : return VREL_PE8;
563 : case 16:
564 : return VREL_PE16;
565 : case 32:
566 : return VREL_PE32;
567 : case 64:
568 : return VREL_PE64;
569 : default:
570 : return VREL_VARYING;
571 : }
572 : }
573 :
574 : // Given partial equivalencies T1 and T2, return the smallest kind.
575 :
576 : inline relation_kind
577 9774057 : pe_min (relation_kind t1, relation_kind t2)
578 : {
579 9774057 : gcc_checking_assert (relation_partial_equiv_p (t1));
580 9774057 : gcc_checking_assert (relation_partial_equiv_p (t2));
581 : // VREL_PE are declared small to large, so simple min will suffice.
582 9774057 : return MIN (t1, t2);
583 : }
584 : #endif /* GCC_VALUE_RELATION_H */
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