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MemorySSA.h
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1 //===- MemorySSA.h - Build Memory SSA ---------------------------*- C++ -*-===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 /// \file
10 /// This file exposes an interface to building/using memory SSA to
11 /// walk memory instructions using a use/def graph.
12 ///
13 /// Memory SSA class builds an SSA form that links together memory access
14 /// instructions such as loads, stores, atomics, and calls. Additionally, it
15 /// does a trivial form of "heap versioning" Every time the memory state changes
16 /// in the program, we generate a new heap version. It generates
17 /// MemoryDef/Uses/Phis that are overlayed on top of the existing instructions.
18 ///
19 /// As a trivial example,
20 /// define i32 @main() #0 {
21 /// entry:
22 /// %call = call noalias i8* @_Znwm(i64 4) #2
23 /// %0 = bitcast i8* %call to i32*
24 /// %call1 = call noalias i8* @_Znwm(i64 4) #2
25 /// %1 = bitcast i8* %call1 to i32*
26 /// store i32 5, i32* %0, align 4
27 /// store i32 7, i32* %1, align 4
28 /// %2 = load i32* %0, align 4
29 /// %3 = load i32* %1, align 4
30 /// %add = add nsw i32 %2, %3
31 /// ret i32 %add
32 /// }
33 ///
34 /// Will become
35 /// define i32 @main() #0 {
36 /// entry:
37 /// ; 1 = MemoryDef(0)
38 /// %call = call noalias i8* @_Znwm(i64 4) #3
39 /// %2 = bitcast i8* %call to i32*
40 /// ; 2 = MemoryDef(1)
41 /// %call1 = call noalias i8* @_Znwm(i64 4) #3
42 /// %4 = bitcast i8* %call1 to i32*
43 /// ; 3 = MemoryDef(2)
44 /// store i32 5, i32* %2, align 4
45 /// ; 4 = MemoryDef(3)
46 /// store i32 7, i32* %4, align 4
47 /// ; MemoryUse(3)
48 /// %7 = load i32* %2, align 4
49 /// ; MemoryUse(4)
50 /// %8 = load i32* %4, align 4
51 /// %add = add nsw i32 %7, %8
52 /// ret i32 %add
53 /// }
54 ///
55 /// Given this form, all the stores that could ever effect the load at %8 can be
56 /// gotten by using the MemoryUse associated with it, and walking from use to
57 /// def until you hit the top of the function.
58 ///
59 /// Each def also has a list of users associated with it, so you can walk from
60 /// both def to users, and users to defs. Note that we disambiguate MemoryUses,
61 /// but not the RHS of MemoryDefs. You can see this above at %7, which would
62 /// otherwise be a MemoryUse(4). Being disambiguated means that for a given
63 /// store, all the MemoryUses on its use lists are may-aliases of that store
64 /// (but the MemoryDefs on its use list may not be).
65 ///
66 /// MemoryDefs are not disambiguated because it would require multiple reaching
67 /// definitions, which would require multiple phis, and multiple memoryaccesses
68 /// per instruction.
69 //
70 //===----------------------------------------------------------------------===//
71 
72 #ifndef LLVM_ANALYSIS_MEMORYSSA_H
73 #define LLVM_ANALYSIS_MEMORYSSA_H
74 
75 #include "llvm/ADT/DenseMap.h"
76 #include "llvm/ADT/GraphTraits.h"
77 #include "llvm/ADT/SmallPtrSet.h"
78 #include "llvm/ADT/SmallVector.h"
79 #include "llvm/ADT/ilist.h"
80 #include "llvm/ADT/ilist_node.h"
81 #include "llvm/ADT/iterator.h"
83 #include "llvm/ADT/simple_ilist.h"
87 #include "llvm/IR/BasicBlock.h"
88 #include "llvm/IR/DerivedUser.h"
89 #include "llvm/IR/Dominators.h"
90 #include "llvm/IR/Module.h"
91 #include "llvm/IR/Type.h"
92 #include "llvm/IR/Use.h"
93 #include "llvm/IR/User.h"
94 #include "llvm/IR/Value.h"
95 #include "llvm/IR/ValueHandle.h"
96 #include "llvm/Pass.h"
97 #include "llvm/Support/Casting.h"
98 #include <algorithm>
99 #include <cassert>
100 #include <cstddef>
101 #include <iterator>
102 #include <memory>
103 #include <utility>
104 
105 namespace llvm {
106 
107 class Function;
108 class Instruction;
109 class MemoryAccess;
110 class MemorySSAWalker;
111 class LLVMContext;
112 class raw_ostream;
113 
114 namespace MSSAHelpers {
115 
116 struct AllAccessTag {};
117 struct DefsOnlyTag {};
118 
119 } // end namespace MSSAHelpers
120 
121 enum : unsigned {
122  // Used to signify what the default invalid ID is for MemoryAccess's
123  // getID()
125 };
126 
127 template <class T> class memoryaccess_def_iterator_base;
131 
132 // The base for all memory accesses. All memory accesses in a block are
133 // linked together using an intrusive list.
135  : public DerivedUser,
136  public ilist_node<MemoryAccess, ilist_tag<MSSAHelpers::AllAccessTag>>,
137  public ilist_node<MemoryAccess, ilist_tag<MSSAHelpers::DefsOnlyTag>> {
138 public:
139  using AllAccessType =
141  using DefsOnlyType =
143 
144  MemoryAccess(const MemoryAccess &) = delete;
145  MemoryAccess &operator=(const MemoryAccess &) = delete;
146 
147  void *operator new(size_t) = delete;
148 
149  // Methods for support type inquiry through isa, cast, and
150  // dyn_cast
151  static bool classof(const Value *V) {
152  unsigned ID = V->getValueID();
153  return ID == MemoryUseVal || ID == MemoryPhiVal || ID == MemoryDefVal;
154  }
155 
156  BasicBlock *getBlock() const { return Block; }
157 
158  void print(raw_ostream &OS) const;
159  void dump() const;
160 
161  /// The user iterators for a memory access
164 
165  /// This iterator walks over all of the defs in a given
166  /// MemoryAccess. For MemoryPhi nodes, this walks arguments. For
167  /// MemoryUse/MemoryDef, this walks the defining access.
168  memoryaccess_def_iterator defs_begin();
169  const_memoryaccess_def_iterator defs_begin() const;
170  memoryaccess_def_iterator defs_end();
171  const_memoryaccess_def_iterator defs_end() const;
172 
173  /// Get the iterators for the all access list and the defs only list
174  /// We default to the all access list.
176  return this->AllAccessType::getIterator();
177  }
179  return this->AllAccessType::getIterator();
180  }
182  return this->AllAccessType::getReverseIterator();
183  }
185  return this->AllAccessType::getReverseIterator();
186  }
188  return this->DefsOnlyType::getIterator();
189  }
191  return this->DefsOnlyType::getIterator();
192  }
194  return this->DefsOnlyType::getReverseIterator();
195  }
197  return this->DefsOnlyType::getReverseIterator();
198  }
199 
200 protected:
201  friend class MemoryDef;
202  friend class MemoryPhi;
203  friend class MemorySSA;
204  friend class MemoryUse;
205  friend class MemoryUseOrDef;
206 
207  /// Used by MemorySSA to change the block of a MemoryAccess when it is
208  /// moved.
209  void setBlock(BasicBlock *BB) { Block = BB; }
210 
211  /// Used for debugging and tracking things about MemoryAccesses.
212  /// Guaranteed unique among MemoryAccesses, no guarantees otherwise.
213  inline unsigned getID() const;
214 
215  MemoryAccess(LLVMContext &C, unsigned Vty, DeleteValueTy DeleteValue,
216  BasicBlock *BB, unsigned NumOperands)
217  : DerivedUser(Type::getVoidTy(C), Vty, nullptr, NumOperands, DeleteValue),
218  Block(BB) {}
219 
220  // Use deleteValue() to delete a generic MemoryAccess.
221  ~MemoryAccess() = default;
222 
223 private:
224  BasicBlock *Block;
225 };
226 
227 template <>
229  static void deleteNode(MemoryAccess *MA) { MA->deleteValue(); }
230 };
231 
233  MA.print(OS);
234  return OS;
235 }
236 
237 /// Class that has the common methods + fields of memory uses/defs. It's
238 /// a little awkward to have, but there are many cases where we want either a
239 /// use or def, and there are many cases where uses are needed (defs aren't
240 /// acceptable), and vice-versa.
241 ///
242 /// This class should never be instantiated directly; make a MemoryUse or
243 /// MemoryDef instead.
244 class MemoryUseOrDef : public MemoryAccess {
245 public:
246  void *operator new(size_t) = delete;
247 
249 
250  /// Get the instruction that this MemoryUse represents.
251  Instruction *getMemoryInst() const { return MemoryInstruction; }
252 
253  /// Get the access that produces the memory state used by this Use.
254  MemoryAccess *getDefiningAccess() const { return getOperand(0); }
255 
256  static bool classof(const Value *MA) {
257  return MA->getValueID() == MemoryUseVal || MA->getValueID() == MemoryDefVal;
258  }
259 
260  // Sadly, these have to be public because they are needed in some of the
261  // iterators.
262  inline bool isOptimized() const;
263  inline MemoryAccess *getOptimized() const;
264  inline void setOptimized(MemoryAccess *);
265 
266  // Retrieve AliasResult type of the optimized access. Ideally this would be
267  // returned by the caching walker and may go away in the future.
269  return OptimizedAccessAlias;
270  }
271 
272  /// Reset the ID of what this MemoryUse was optimized to, causing it to
273  /// be rewalked by the walker if necessary.
274  /// This really should only be called by tests.
275  inline void resetOptimized();
276 
277 protected:
278  friend class MemorySSA;
279  friend class MemorySSAUpdater;
280 
281  MemoryUseOrDef(LLVMContext &C, MemoryAccess *DMA, unsigned Vty,
282  DeleteValueTy DeleteValue, Instruction *MI, BasicBlock *BB,
283  unsigned NumOperands)
284  : MemoryAccess(C, Vty, DeleteValue, BB, NumOperands),
285  MemoryInstruction(MI), OptimizedAccessAlias(MayAlias) {
286  setDefiningAccess(DMA);
287  }
288 
289  // Use deleteValue() to delete a generic MemoryUseOrDef.
290  ~MemoryUseOrDef() = default;
291 
293  OptimizedAccessAlias = AR;
294  }
295 
296  void setDefiningAccess(MemoryAccess *DMA, bool Optimized = false,
298  if (!Optimized) {
299  setOperand(0, DMA);
300  return;
301  }
302  setOptimized(DMA);
303  setOptimizedAccessType(AR);
304  }
305 
306 private:
307  Instruction *MemoryInstruction;
308  Optional<AliasResult> OptimizedAccessAlias;
309 };
310 
311 /// Represents read-only accesses to memory
312 ///
313 /// In particular, the set of Instructions that will be represented by
314 /// MemoryUse's is exactly the set of Instructions for which
315 /// AliasAnalysis::getModRefInfo returns "Ref".
316 class MemoryUse final : public MemoryUseOrDef {
317 public:
319 
321  : MemoryUseOrDef(C, DMA, MemoryUseVal, deleteMe, MI, BB,
322  /*NumOperands=*/1) {}
323 
324  // allocate space for exactly one operand
325  void *operator new(size_t s) { return User::operator new(s, 1); }
326 
327  static bool classof(const Value *MA) {
328  return MA->getValueID() == MemoryUseVal;
329  }
330 
331  void print(raw_ostream &OS) const;
332 
334  OptimizedID = DMA->getID();
335  setOperand(0, DMA);
336  }
337 
338  bool isOptimized() const {
339  return getDefiningAccess() && OptimizedID == getDefiningAccess()->getID();
340  }
341 
343  return getDefiningAccess();
344  }
345 
346  void resetOptimized() {
347  OptimizedID = INVALID_MEMORYACCESS_ID;
348  }
349 
350 protected:
351  friend class MemorySSA;
352 
353 private:
354  static void deleteMe(DerivedUser *Self);
355 
356  unsigned OptimizedID = INVALID_MEMORYACCESS_ID;
357 };
358 
359 template <>
360 struct OperandTraits<MemoryUse> : public FixedNumOperandTraits<MemoryUse, 1> {};
362 
363 /// Represents a read-write access to memory, whether it is a must-alias,
364 /// or a may-alias.
365 ///
366 /// In particular, the set of Instructions that will be represented by
367 /// MemoryDef's is exactly the set of Instructions for which
368 /// AliasAnalysis::getModRefInfo returns "Mod" or "ModRef".
369 /// Note that, in order to provide def-def chains, all defs also have a use
370 /// associated with them. This use points to the nearest reaching
371 /// MemoryDef/MemoryPhi.
372 class MemoryDef final : public MemoryUseOrDef {
373 public:
374  friend class MemorySSA;
375 
377 
379  unsigned Ver)
380  : MemoryUseOrDef(C, DMA, MemoryDefVal, deleteMe, MI, BB,
381  /*NumOperands=*/2),
382  ID(Ver) {}
383 
384  // allocate space for exactly two operands
385  void *operator new(size_t s) { return User::operator new(s, 2); }
386 
387  static bool classof(const Value *MA) {
388  return MA->getValueID() == MemoryDefVal;
389  }
390 
392  setOperand(1, MA);
393  OptimizedID = MA->getID();
394  }
395 
397  return cast_or_null<MemoryAccess>(getOperand(1));
398  }
399 
400  bool isOptimized() const {
401  return getOptimized() && OptimizedID == getOptimized()->getID();
402  }
403 
404  void resetOptimized() {
405  OptimizedID = INVALID_MEMORYACCESS_ID;
406  setOperand(1, nullptr);
407  }
408 
409  void print(raw_ostream &OS) const;
410 
411  unsigned getID() const { return ID; }
412 
413 private:
414  static void deleteMe(DerivedUser *Self);
415 
416  const unsigned ID;
417  unsigned OptimizedID = INVALID_MEMORYACCESS_ID;
418 };
419 
420 template <>
421 struct OperandTraits<MemoryDef> : public FixedNumOperandTraits<MemoryDef, 2> {};
423 
424 template <>
426  static Use *op_begin(MemoryUseOrDef *MUD) {
427  if (auto *MU = dyn_cast<MemoryUse>(MUD))
429  return OperandTraits<MemoryDef>::op_begin(cast<MemoryDef>(MUD));
430  }
431 
432  static Use *op_end(MemoryUseOrDef *MUD) {
433  if (auto *MU = dyn_cast<MemoryUse>(MUD))
435  return OperandTraits<MemoryDef>::op_end(cast<MemoryDef>(MUD));
436  }
437 
438  static unsigned operands(const MemoryUseOrDef *MUD) {
439  if (const auto *MU = dyn_cast<MemoryUse>(MUD))
441  return OperandTraits<MemoryDef>::operands(cast<MemoryDef>(MUD));
442  }
443 };
445 
446 /// Represents phi nodes for memory accesses.
447 ///
448 /// These have the same semantic as regular phi nodes, with the exception that
449 /// only one phi will ever exist in a given basic block.
450 /// Guaranteeing one phi per block means guaranteeing there is only ever one
451 /// valid reaching MemoryDef/MemoryPHI along each path to the phi node.
452 /// This is ensured by not allowing disambiguation of the RHS of a MemoryDef or
453 /// a MemoryPhi's operands.
454 /// That is, given
455 /// if (a) {
456 /// store %a
457 /// store %b
458 /// }
459 /// it *must* be transformed into
460 /// if (a) {
461 /// 1 = MemoryDef(liveOnEntry)
462 /// store %a
463 /// 2 = MemoryDef(1)
464 /// store %b
465 /// }
466 /// and *not*
467 /// if (a) {
468 /// 1 = MemoryDef(liveOnEntry)
469 /// store %a
470 /// 2 = MemoryDef(liveOnEntry)
471 /// store %b
472 /// }
473 /// even if the two stores do not conflict. Otherwise, both 1 and 2 reach the
474 /// end of the branch, and if there are not two phi nodes, one will be
475 /// disconnected completely from the SSA graph below that point.
476 /// Because MemoryUse's do not generate new definitions, they do not have this
477 /// issue.
478 class MemoryPhi final : public MemoryAccess {
479  // allocate space for exactly zero operands
480  void *operator new(size_t s) { return User::operator new(s); }
481 
482 public:
483  /// Provide fast operand accessors
485 
486  MemoryPhi(LLVMContext &C, BasicBlock *BB, unsigned Ver, unsigned NumPreds = 0)
487  : MemoryAccess(C, MemoryPhiVal, deleteMe, BB, 0), ID(Ver),
488  ReservedSpace(NumPreds) {
489  allocHungoffUses(ReservedSpace);
490  }
491 
492  // Block iterator interface. This provides access to the list of incoming
493  // basic blocks, which parallels the list of incoming values.
496 
498  auto *Ref = reinterpret_cast<Use::UserRef *>(op_begin() + ReservedSpace);
499  return reinterpret_cast<block_iterator>(Ref + 1);
500  }
501 
503  const auto *Ref =
504  reinterpret_cast<const Use::UserRef *>(op_begin() + ReservedSpace);
505  return reinterpret_cast<const_block_iterator>(Ref + 1);
506  }
507 
508  block_iterator block_end() { return block_begin() + getNumOperands(); }
509 
511  return block_begin() + getNumOperands();
512  }
513 
515  return make_range(block_begin(), block_end());
516  }
517 
519  return make_range(block_begin(), block_end());
520  }
521 
522  op_range incoming_values() { return operands(); }
523 
524  const_op_range incoming_values() const { return operands(); }
525 
526  /// Return the number of incoming edges
527  unsigned getNumIncomingValues() const { return getNumOperands(); }
528 
529  /// Return incoming value number x
530  MemoryAccess *getIncomingValue(unsigned I) const { return getOperand(I); }
531  void setIncomingValue(unsigned I, MemoryAccess *V) {
532  assert(V && "PHI node got a null value!");
533  setOperand(I, V);
534  }
535 
536  static unsigned getOperandNumForIncomingValue(unsigned I) { return I; }
537  static unsigned getIncomingValueNumForOperand(unsigned I) { return I; }
538 
539  /// Return incoming basic block number @p i.
540  BasicBlock *getIncomingBlock(unsigned I) const { return block_begin()[I]; }
541 
542  /// Return incoming basic block corresponding
543  /// to an operand of the PHI.
544  BasicBlock *getIncomingBlock(const Use &U) const {
545  assert(this == U.getUser() && "Iterator doesn't point to PHI's Uses?");
546  return getIncomingBlock(unsigned(&U - op_begin()));
547  }
548 
549  /// Return incoming basic block corresponding
550  /// to value use iterator.
552  return getIncomingBlock(I.getUse());
553  }
554 
555  void setIncomingBlock(unsigned I, BasicBlock *BB) {
556  assert(BB && "PHI node got a null basic block!");
557  block_begin()[I] = BB;
558  }
559 
560  /// Add an incoming value to the end of the PHI list
562  if (getNumOperands() == ReservedSpace)
563  growOperands(); // Get more space!
564  // Initialize some new operands.
565  setNumHungOffUseOperands(getNumOperands() + 1);
566  setIncomingValue(getNumOperands() - 1, V);
567  setIncomingBlock(getNumOperands() - 1, BB);
568  }
569 
570  /// Return the first index of the specified basic
571  /// block in the value list for this PHI. Returns -1 if no instance.
572  int getBasicBlockIndex(const BasicBlock *BB) const {
573  for (unsigned I = 0, E = getNumOperands(); I != E; ++I)
574  if (block_begin()[I] == BB)
575  return I;
576  return -1;
577  }
578 
580  int Idx = getBasicBlockIndex(BB);
581  assert(Idx >= 0 && "Invalid basic block argument!");
582  return getIncomingValue(Idx);
583  }
584 
585  // After deleting incoming position I, the order of incoming may be changed.
586  void unorderedDeleteIncoming(unsigned I) {
587  unsigned E = getNumOperands();
588  assert(I < E && "Cannot remove out of bounds Phi entry.");
589  // MemoryPhi must have at least two incoming values, otherwise the MemoryPhi
590  // itself should be deleted.
591  assert(E >= 2 && "Cannot only remove incoming values in MemoryPhis with "
592  "at least 2 values.");
593  setIncomingValue(I, getIncomingValue(E - 1));
594  setIncomingBlock(I, block_begin()[E - 1]);
595  setOperand(E - 1, nullptr);
596  block_begin()[E - 1] = nullptr;
597  setNumHungOffUseOperands(getNumOperands() - 1);
598  }
599 
600  // After deleting entries that satisfy Pred, remaining entries may have
601  // changed order.
602  template <typename Fn> void unorderedDeleteIncomingIf(Fn &&Pred) {
603  for (unsigned I = 0, E = getNumOperands(); I != E; ++I)
604  if (Pred(getIncomingValue(I), getIncomingBlock(I))) {
605  unorderedDeleteIncoming(I);
606  E = getNumOperands();
607  --I;
608  }
609  assert(getNumOperands() >= 1 &&
610  "Cannot remove all incoming blocks in a MemoryPhi.");
611  }
612 
613  // After deleting incoming block BB, the incoming blocks order may be changed.
615  unorderedDeleteIncomingIf(
616  [&](const MemoryAccess *, const BasicBlock *B) { return BB == B; });
617  }
618 
619  // After deleting incoming memory access MA, the incoming accesses order may
620  // be changed.
622  unorderedDeleteIncomingIf(
623  [&](const MemoryAccess *M, const BasicBlock *) { return MA == M; });
624  }
625 
626  static bool classof(const Value *V) {
627  return V->getValueID() == MemoryPhiVal;
628  }
629 
630  void print(raw_ostream &OS) const;
631 
632  unsigned getID() const { return ID; }
633 
634 protected:
635  friend class MemorySSA;
636 
637  /// this is more complicated than the generic
638  /// User::allocHungoffUses, because we have to allocate Uses for the incoming
639  /// values and pointers to the incoming blocks, all in one allocation.
640  void allocHungoffUses(unsigned N) {
641  User::allocHungoffUses(N, /* IsPhi */ true);
642  }
643 
644 private:
645  // For debugging only
646  const unsigned ID;
647  unsigned ReservedSpace;
648 
649  /// This grows the operand list in response to a push_back style of
650  /// operation. This grows the number of ops by 1.5 times.
651  void growOperands() {
652  unsigned E = getNumOperands();
653  // 2 op PHI nodes are VERY common, so reserve at least enough for that.
654  ReservedSpace = std::max(E + E / 2, 2u);
655  growHungoffUses(ReservedSpace, /* IsPhi */ true);
656  }
657 
658  static void deleteMe(DerivedUser *Self);
659 };
660 
661 inline unsigned MemoryAccess::getID() const {
662  assert((isa<MemoryDef>(this) || isa<MemoryPhi>(this)) &&
663  "only memory defs and phis have ids");
664  if (const auto *MD = dyn_cast<MemoryDef>(this))
665  return MD->getID();
666  return cast<MemoryPhi>(this)->getID();
667 }
668 
669 inline bool MemoryUseOrDef::isOptimized() const {
670  if (const auto *MD = dyn_cast<MemoryDef>(this))
671  return MD->isOptimized();
672  return cast<MemoryUse>(this)->isOptimized();
673 }
674 
676  if (const auto *MD = dyn_cast<MemoryDef>(this))
677  return MD->getOptimized();
678  return cast<MemoryUse>(this)->getOptimized();
679 }
680 
682  if (auto *MD = dyn_cast<MemoryDef>(this))
683  MD->setOptimized(MA);
684  else
685  cast<MemoryUse>(this)->setOptimized(MA);
686 }
687 
689  if (auto *MD = dyn_cast<MemoryDef>(this))
690  MD->resetOptimized();
691  else
692  cast<MemoryUse>(this)->resetOptimized();
693 }
694 
695 template <> struct OperandTraits<MemoryPhi> : public HungoffOperandTraits<2> {};
697 
698 /// Encapsulates MemorySSA, including all data associated with memory
699 /// accesses.
700 class MemorySSA {
701 public:
703  ~MemorySSA();
704 
705  MemorySSAWalker *getWalker();
706  MemorySSAWalker *getSkipSelfWalker();
707 
708  /// Given a memory Mod/Ref'ing instruction, get the MemorySSA
709  /// access associated with it. If passed a basic block gets the memory phi
710  /// node that exists for that block, if there is one. Otherwise, this will get
711  /// a MemoryUseOrDef.
713  return cast_or_null<MemoryUseOrDef>(ValueToMemoryAccess.lookup(I));
714  }
715 
716  MemoryPhi *getMemoryAccess(const BasicBlock *BB) const {
717  return cast_or_null<MemoryPhi>(ValueToMemoryAccess.lookup(cast<Value>(BB)));
718  }
719 
720  void dump() const;
721  void print(raw_ostream &) const;
722 
723  /// Return true if \p MA represents the live on entry value
724  ///
725  /// Loads and stores from pointer arguments and other global values may be
726  /// defined by memory operations that do not occur in the current function, so
727  /// they may be live on entry to the function. MemorySSA represents such
728  /// memory state by the live on entry definition, which is guaranteed to occur
729  /// before any other memory access in the function.
730  inline bool isLiveOnEntryDef(const MemoryAccess *MA) const {
731  return MA == LiveOnEntryDef.get();
732  }
733 
734  inline MemoryAccess *getLiveOnEntryDef() const {
735  return LiveOnEntryDef.get();
736  }
737 
738  // Sadly, iplists, by default, owns and deletes pointers added to the
739  // list. It's not currently possible to have two iplists for the same type,
740  // where one owns the pointers, and one does not. This is because the traits
741  // are per-type, not per-tag. If this ever changes, we should make the
742  // DefList an iplist.
744  using DefsList =
746 
747  /// Return the list of MemoryAccess's for a given basic block.
748  ///
749  /// This list is not modifiable by the user.
750  const AccessList *getBlockAccesses(const BasicBlock *BB) const {
751  return getWritableBlockAccesses(BB);
752  }
753 
754  /// Return the list of MemoryDef's and MemoryPhi's for a given basic
755  /// block.
756  ///
757  /// This list is not modifiable by the user.
758  const DefsList *getBlockDefs(const BasicBlock *BB) const {
759  return getWritableBlockDefs(BB);
760  }
761 
762  /// Given two memory accesses in the same basic block, determine
763  /// whether MemoryAccess \p A dominates MemoryAccess \p B.
764  bool locallyDominates(const MemoryAccess *A, const MemoryAccess *B) const;
765 
766  /// Given two memory accesses in potentially different blocks,
767  /// determine whether MemoryAccess \p A dominates MemoryAccess \p B.
768  bool dominates(const MemoryAccess *A, const MemoryAccess *B) const;
769 
770  /// Given a MemoryAccess and a Use, determine whether MemoryAccess \p A
771  /// dominates Use \p B.
772  bool dominates(const MemoryAccess *A, const Use &B) const;
773 
774  /// Verify that MemorySSA is self consistent (IE definitions dominate
775  /// all uses, uses appear in the right places). This is used by unit tests.
776  void verifyMemorySSA() const;
777 
778  /// Used in various insertion functions to specify whether we are talking
779  /// about the beginning or end of a block.
780  enum InsertionPlace { Beginning, End };
781 
782 protected:
783  // Used by Memory SSA annotater, dumpers, and wrapper pass
786  friend class MemorySSAUpdater;
787 
788  void verifyDefUses(Function &F) const;
789  void verifyDomination(Function &F) const;
790  void verifyOrdering(Function &F) const;
791  void verifyDominationNumbers(const Function &F) const;
792 
793  // This is used by the use optimizer and updater.
795  auto It = PerBlockAccesses.find(BB);
796  return It == PerBlockAccesses.end() ? nullptr : It->second.get();
797  }
798 
799  // This is used by the use optimizer and updater.
801  auto It = PerBlockDefs.find(BB);
802  return It == PerBlockDefs.end() ? nullptr : It->second.get();
803  }
804 
805  // These is used by the updater to perform various internal MemorySSA
806  // machinsations. They do not always leave the IR in a correct state, and
807  // relies on the updater to fixup what it breaks, so it is not public.
808 
809  void moveTo(MemoryUseOrDef *What, BasicBlock *BB, AccessList::iterator Where);
810  void moveTo(MemoryAccess *What, BasicBlock *BB, InsertionPlace Point);
811 
812  // Rename the dominator tree branch rooted at BB.
813  void renamePass(BasicBlock *BB, MemoryAccess *IncomingVal,
815  renamePass(DT->getNode(BB), IncomingVal, Visited, true, true);
816  }
817 
818  void removeFromLookups(MemoryAccess *);
819  void removeFromLists(MemoryAccess *, bool ShouldDelete = true);
820  void insertIntoListsForBlock(MemoryAccess *, const BasicBlock *,
822  void insertIntoListsBefore(MemoryAccess *, const BasicBlock *,
823  AccessList::iterator);
824  MemoryUseOrDef *createDefinedAccess(Instruction *, MemoryAccess *,
825  const MemoryUseOrDef *Template = nullptr);
826 
827 private:
828  class ClobberWalkerBase;
829  class CachingWalker;
830  class SkipSelfWalker;
831  class OptimizeUses;
832 
833  CachingWalker *getWalkerImpl();
834  void buildMemorySSA();
835  void optimizeUses();
836 
837  void prepareForMoveTo(MemoryAccess *, BasicBlock *);
838  void verifyUseInDefs(MemoryAccess *, MemoryAccess *) const;
839 
842 
843  void
844  determineInsertionPoint(const SmallPtrSetImpl<BasicBlock *> &DefiningBlocks);
845  void markUnreachableAsLiveOnEntry(BasicBlock *BB);
846  bool dominatesUse(const MemoryAccess *, const MemoryAccess *) const;
847  MemoryPhi *createMemoryPhi(BasicBlock *BB);
848  MemoryUseOrDef *createNewAccess(Instruction *,
849  const MemoryUseOrDef *Template = nullptr);
850  MemoryAccess *findDominatingDef(BasicBlock *, enum InsertionPlace);
851  void placePHINodes(const SmallPtrSetImpl<BasicBlock *> &);
852  MemoryAccess *renameBlock(BasicBlock *, MemoryAccess *, bool);
853  void renameSuccessorPhis(BasicBlock *, MemoryAccess *, bool);
854  void renamePass(DomTreeNode *, MemoryAccess *IncomingVal,
856  bool SkipVisited = false, bool RenameAllUses = false);
857  AccessList *getOrCreateAccessList(const BasicBlock *);
858  DefsList *getOrCreateDefsList(const BasicBlock *);
859  void renumberBlock(const BasicBlock *) const;
860  AliasAnalysis *AA;
861  DominatorTree *DT;
862  Function &F;
863 
864  // Memory SSA mappings
865  DenseMap<const Value *, MemoryAccess *> ValueToMemoryAccess;
866 
867  // These two mappings contain the main block to access/def mappings for
868  // MemorySSA. The list contained in PerBlockAccesses really owns all the
869  // MemoryAccesses.
870  // Both maps maintain the invariant that if a block is found in them, the
871  // corresponding list is not empty, and if a block is not found in them, the
872  // corresponding list is empty.
873  AccessMap PerBlockAccesses;
874  DefsMap PerBlockDefs;
875  std::unique_ptr<MemoryAccess, ValueDeleter> LiveOnEntryDef;
876 
877  // Domination mappings
878  // Note that the numbering is local to a block, even though the map is
879  // global.
880  mutable SmallPtrSet<const BasicBlock *, 16> BlockNumberingValid;
881  mutable DenseMap<const MemoryAccess *, unsigned long> BlockNumbering;
882 
883  // Memory SSA building info
884  std::unique_ptr<ClobberWalkerBase> WalkerBase;
885  std::unique_ptr<CachingWalker> Walker;
886  std::unique_ptr<SkipSelfWalker> SkipWalker;
887  unsigned NextID;
888 };
889 
890 // Internal MemorySSA utils, for use by MemorySSA classes and walkers
892 protected:
893  friend class GVNHoist;
894  friend class MemorySSAWalker;
895 
896  // This function should not be used by new passes.
897  static bool defClobbersUseOrDef(MemoryDef *MD, const MemoryUseOrDef *MU,
898  AliasAnalysis &AA);
899 };
900 
901 // This pass does eager building and then printing of MemorySSA. It is used by
902 // the tests to be able to build, dump, and verify Memory SSA.
904 public:
906 
907  bool runOnFunction(Function &) override;
908  void getAnalysisUsage(AnalysisUsage &AU) const override;
909 
910  static char ID;
911 };
912 
913 /// An analysis that produces \c MemorySSA for a function.
914 ///
915 class MemorySSAAnalysis : public AnalysisInfoMixin<MemorySSAAnalysis> {
917 
918  static AnalysisKey Key;
919 
920 public:
921  // Wrap MemorySSA result to ensure address stability of internal MemorySSA
922  // pointers after construction. Use a wrapper class instead of plain
923  // unique_ptr<MemorySSA> to avoid build breakage on MSVC.
924  struct Result {
925  Result(std::unique_ptr<MemorySSA> &&MSSA) : MSSA(std::move(MSSA)) {}
926 
927  MemorySSA &getMSSA() { return *MSSA.get(); }
928 
929  std::unique_ptr<MemorySSA> MSSA;
930  };
931 
933 };
934 
935 /// Printer pass for \c MemorySSA.
936 class MemorySSAPrinterPass : public PassInfoMixin<MemorySSAPrinterPass> {
937  raw_ostream &OS;
938 
939 public:
940  explicit MemorySSAPrinterPass(raw_ostream &OS) : OS(OS) {}
941 
943 };
944 
945 /// Verifier pass for \c MemorySSA.
946 struct MemorySSAVerifierPass : PassInfoMixin<MemorySSAVerifierPass> {
948 };
949 
950 /// Legacy analysis pass which computes \c MemorySSA.
952 public:
954 
955  static char ID;
956 
957  bool runOnFunction(Function &) override;
958  void releaseMemory() override;
959  MemorySSA &getMSSA() { return *MSSA; }
960  const MemorySSA &getMSSA() const { return *MSSA; }
961 
962  void getAnalysisUsage(AnalysisUsage &AU) const override;
963 
964  void verifyAnalysis() const override;
965  void print(raw_ostream &OS, const Module *M = nullptr) const override;
966 
967 private:
968  std::unique_ptr<MemorySSA> MSSA;
969 };
970 
971 /// This is the generic walker interface for walkers of MemorySSA.
972 /// Walkers are used to be able to further disambiguate the def-use chains
973 /// MemorySSA gives you, or otherwise produce better info than MemorySSA gives
974 /// you.
975 /// In particular, while the def-use chains provide basic information, and are
976 /// guaranteed to give, for example, the nearest may-aliasing MemoryDef for a
977 /// MemoryUse as AliasAnalysis considers it, a user mant want better or other
978 /// information. In particular, they may want to use SCEV info to further
979 /// disambiguate memory accesses, or they may want the nearest dominating
980 /// may-aliasing MemoryDef for a call or a store. This API enables a
981 /// standardized interface to getting and using that info.
983 public:
985  virtual ~MemorySSAWalker() = default;
986 
988 
989  /// Given a memory Mod/Ref/ModRef'ing instruction, calling this
990  /// will give you the nearest dominating MemoryAccess that Mod's the location
991  /// the instruction accesses (by skipping any def which AA can prove does not
992  /// alias the location(s) accessed by the instruction given).
993  ///
994  /// Note that this will return a single access, and it must dominate the
995  /// Instruction, so if an operand of a MemoryPhi node Mod's the instruction,
996  /// this will return the MemoryPhi, not the operand. This means that
997  /// given:
998  /// if (a) {
999  /// 1 = MemoryDef(liveOnEntry)
1000  /// store %a
1001  /// } else {
1002  /// 2 = MemoryDef(liveOnEntry)
1003  /// store %b
1004  /// }
1005  /// 3 = MemoryPhi(2, 1)
1006  /// MemoryUse(3)
1007  /// load %a
1008  ///
1009  /// calling this API on load(%a) will return the MemoryPhi, not the MemoryDef
1010  /// in the if (a) branch.
1012  MemoryAccess *MA = MSSA->getMemoryAccess(I);
1013  assert(MA && "Handed an instruction that MemorySSA doesn't recognize?");
1014  return getClobberingMemoryAccess(MA);
1015  }
1016 
1017  /// Does the same thing as getClobberingMemoryAccess(const Instruction *I),
1018  /// but takes a MemoryAccess instead of an Instruction.
1019  virtual MemoryAccess *getClobberingMemoryAccess(MemoryAccess *) = 0;
1020 
1021  /// Given a potentially clobbering memory access and a new location,
1022  /// calling this will give you the nearest dominating clobbering MemoryAccess
1023  /// (by skipping non-aliasing def links).
1024  ///
1025  /// This version of the function is mainly used to disambiguate phi translated
1026  /// pointers, where the value of a pointer may have changed from the initial
1027  /// memory access. Note that this expects to be handed either a MemoryUse,
1028  /// or an already potentially clobbering access. Unlike the above API, if
1029  /// given a MemoryDef that clobbers the pointer as the starting access, it
1030  /// will return that MemoryDef, whereas the above would return the clobber
1031  /// starting from the use side of the memory def.
1032  virtual MemoryAccess *getClobberingMemoryAccess(MemoryAccess *,
1033  const MemoryLocation &) = 0;
1034 
1035  /// Given a memory access, invalidate anything this walker knows about
1036  /// that access.
1037  /// This API is used by walkers that store information to perform basic cache
1038  /// invalidation. This will be called by MemorySSA at appropriate times for
1039  /// the walker it uses or returns.
1040  virtual void invalidateInfo(MemoryAccess *) {}
1041 
1042  virtual void verify(const MemorySSA *MSSA) { assert(MSSA == this->MSSA); }
1043 
1044 protected:
1045  friend class MemorySSA; // For updating MSSA pointer in MemorySSA move
1046  // constructor.
1048 };
1049 
1050 /// A MemorySSAWalker that does no alias queries, or anything else. It
1051 /// simply returns the links as they were constructed by the builder.
1053 public:
1054  // Keep the overrides below from hiding the Instruction overload of
1055  // getClobberingMemoryAccess.
1057 
1058  MemoryAccess *getClobberingMemoryAccess(MemoryAccess *) override;
1059  MemoryAccess *getClobberingMemoryAccess(MemoryAccess *,
1060  const MemoryLocation &) override;
1061 };
1062 
1063 using MemoryAccessPair = std::pair<MemoryAccess *, MemoryLocation>;
1064 using ConstMemoryAccessPair = std::pair<const MemoryAccess *, MemoryLocation>;
1065 
1066 /// Iterator base class used to implement const and non-const iterators
1067 /// over the defining accesses of a MemoryAccess.
1068 template <class T>
1070  : public iterator_facade_base<memoryaccess_def_iterator_base<T>,
1071  std::forward_iterator_tag, T, ptrdiff_t, T *,
1072  T *> {
1073  using BaseT = typename memoryaccess_def_iterator_base::iterator_facade_base;
1074 
1075 public:
1076  memoryaccess_def_iterator_base(T *Start) : Access(Start) {}
1077  memoryaccess_def_iterator_base() = default;
1078 
1079  bool operator==(const memoryaccess_def_iterator_base &Other) const {
1080  return Access == Other.Access && (!Access || ArgNo == Other.ArgNo);
1081  }
1082 
1083  // This is a bit ugly, but for MemoryPHI's, unlike PHINodes, you can't get the
1084  // block from the operand in constant time (In a PHINode, the uselist has
1085  // both, so it's just subtraction). We provide it as part of the
1086  // iterator to avoid callers having to linear walk to get the block.
1087  // If the operation becomes constant time on MemoryPHI's, this bit of
1088  // abstraction breaking should be removed.
1090  MemoryPhi *MP = dyn_cast<MemoryPhi>(Access);
1091  assert(MP && "Tried to get phi arg block when not iterating over a PHI");
1092  return MP->getIncomingBlock(ArgNo);
1093  }
1094 
1095  typename BaseT::iterator::pointer operator*() const {
1096  assert(Access && "Tried to access past the end of our iterator");
1097  // Go to the first argument for phis, and the defining access for everything
1098  // else.
1099  if (MemoryPhi *MP = dyn_cast<MemoryPhi>(Access))
1100  return MP->getIncomingValue(ArgNo);
1101  return cast<MemoryUseOrDef>(Access)->getDefiningAccess();
1102  }
1103 
1104  using BaseT::operator++;
1106  assert(Access && "Hit end of iterator");
1107  if (MemoryPhi *MP = dyn_cast<MemoryPhi>(Access)) {
1108  if (++ArgNo >= MP->getNumIncomingValues()) {
1109  ArgNo = 0;
1110  Access = nullptr;
1111  }
1112  } else {
1113  Access = nullptr;
1114  }
1115  return *this;
1116  }
1117 
1118 private:
1119  T *Access = nullptr;
1120  unsigned ArgNo = 0;
1121 };
1122 
1124  return memoryaccess_def_iterator(this);
1125 }
1126 
1128  return const_memoryaccess_def_iterator(this);
1129 }
1130 
1132  return memoryaccess_def_iterator();
1133 }
1134 
1137 }
1138 
1139 /// GraphTraits for a MemoryAccess, which walks defs in the normal case,
1140 /// and uses in the inverse case.
1141 template <> struct GraphTraits<MemoryAccess *> {
1144 
1145  static NodeRef getEntryNode(NodeRef N) { return N; }
1147  static ChildIteratorType child_end(NodeRef N) { return N->defs_end(); }
1148 };
1149 
1150 template <> struct GraphTraits<Inverse<MemoryAccess *>> {
1153 
1154  static NodeRef getEntryNode(NodeRef N) { return N; }
1156  static ChildIteratorType child_end(NodeRef N) { return N->user_end(); }
1157 };
1158 
1159 /// Provide an iterator that walks defs, giving both the memory access,
1160 /// and the current pointer location, updating the pointer location as it
1161 /// changes due to phi node translation.
1162 ///
1163 /// This iterator, while somewhat specialized, is what most clients actually
1164 /// want when walking upwards through MemorySSA def chains. It takes a pair of
1165 /// <MemoryAccess,MemoryLocation>, and walks defs, properly translating the
1166 /// memory location through phi nodes for the user.
1168  : public iterator_facade_base<upward_defs_iterator,
1169  std::forward_iterator_tag,
1170  const MemoryAccessPair> {
1171  using BaseT = upward_defs_iterator::iterator_facade_base;
1172 
1173 public:
1175  : DefIterator(Info.first), Location(Info.second),
1176  OriginalAccess(Info.first) {
1177  CurrentPair.first = nullptr;
1178 
1179  WalkingPhi = Info.first && isa<MemoryPhi>(Info.first);
1180  fillInCurrentPair();
1181  }
1182 
1183  upward_defs_iterator() { CurrentPair.first = nullptr; }
1184 
1185  bool operator==(const upward_defs_iterator &Other) const {
1186  return DefIterator == Other.DefIterator;
1187  }
1188 
1189  BaseT::iterator::reference operator*() const {
1190  assert(DefIterator != OriginalAccess->defs_end() &&
1191  "Tried to access past the end of our iterator");
1192  return CurrentPair;
1193  }
1194 
1195  using BaseT::operator++;
1197  assert(DefIterator != OriginalAccess->defs_end() &&
1198  "Tried to access past the end of the iterator");
1199  ++DefIterator;
1200  if (DefIterator != OriginalAccess->defs_end())
1201  fillInCurrentPair();
1202  return *this;
1203  }
1204 
1205  BasicBlock *getPhiArgBlock() const { return DefIterator.getPhiArgBlock(); }
1206 
1207 private:
1208  void fillInCurrentPair() {
1209  CurrentPair.first = *DefIterator;
1210  if (WalkingPhi && Location.Ptr) {
1211  PHITransAddr Translator(
1212  const_cast<Value *>(Location.Ptr),
1213  OriginalAccess->getBlock()->getModule()->getDataLayout(), nullptr);
1214  if (!Translator.PHITranslateValue(OriginalAccess->getBlock(),
1215  DefIterator.getPhiArgBlock(), nullptr,
1216  false))
1217  if (Translator.getAddr() != Location.Ptr) {
1218  CurrentPair.second = Location.getWithNewPtr(Translator.getAddr());
1219  return;
1220  }
1221  }
1222  CurrentPair.second = Location;
1223  }
1224 
1225  MemoryAccessPair CurrentPair;
1226  memoryaccess_def_iterator DefIterator;
1227  MemoryLocation Location;
1228  MemoryAccess *OriginalAccess = nullptr;
1229  bool WalkingPhi = false;
1230 };
1231 
1233  return upward_defs_iterator(Pair);
1234 }
1235 
1237 
1240  return make_range(upward_defs_begin(Pair), upward_defs_end());
1241 }
1242 
1243 /// Walks the defining accesses of MemoryDefs. Stops after we hit something that
1244 /// has no defining use (e.g. a MemoryPhi or liveOnEntry). Note that, when
1245 /// comparing against a null def_chain_iterator, this will compare equal only
1246 /// after walking said Phi/liveOnEntry.
1247 ///
1248 /// The UseOptimizedChain flag specifies whether to walk the clobbering
1249 /// access chain, or all the accesses.
1250 ///
1251 /// Normally, MemoryDef are all just def/use linked together, so a def_chain on
1252 /// a MemoryDef will walk all MemoryDefs above it in the program until it hits
1253 /// a phi node. The optimized chain walks the clobbering access of a store.
1254 /// So if you are just trying to find, given a store, what the next
1255 /// thing that would clobber the same memory is, you want the optimized chain.
1256 template <class T, bool UseOptimizedChain = false>
1258  : public iterator_facade_base<def_chain_iterator<T, UseOptimizedChain>,
1259  std::forward_iterator_tag, MemoryAccess *> {
1260  def_chain_iterator() : MA(nullptr) {}
1261  def_chain_iterator(T MA) : MA(MA) {}
1262 
1263  T operator*() const { return MA; }
1264 
1266  // N.B. liveOnEntry has a null defining access.
1267  if (auto *MUD = dyn_cast<MemoryUseOrDef>(MA)) {
1268  if (UseOptimizedChain && MUD->isOptimized())
1269  MA = MUD->getOptimized();
1270  else
1271  MA = MUD->getDefiningAccess();
1272  } else {
1273  MA = nullptr;
1274  }
1275 
1276  return *this;
1277  }
1278 
1279  bool operator==(const def_chain_iterator &O) const { return MA == O.MA; }
1280 
1281 private:
1282  T MA;
1283 };
1284 
1285 template <class T>
1287 def_chain(T MA, MemoryAccess *UpTo = nullptr) {
1288 #ifdef EXPENSIVE_CHECKS
1289  assert((!UpTo || find(def_chain(MA), UpTo) != def_chain_iterator<T>()) &&
1290  "UpTo isn't in the def chain!");
1291 #endif
1293 }
1294 
1295 template <class T>
1298  def_chain_iterator<T, true>(nullptr));
1299 }
1300 
1301 } // end namespace llvm
1302 
1303 #endif // LLVM_ANALYSIS_MEMORYSSA_H
uint64_t CallInst * C
AccessList * getWritableBlockAccesses(const BasicBlock *BB) const
Definition: MemorySSA.h:794
memoryaccess_def_iterator & operator++()
Definition: MemorySSA.h:1105
BasicBlock * getIncomingBlock(MemoryAccess::const_user_iterator I) const
Return incoming basic block corresponding to value use iterator.
Definition: MemorySSA.h:551
GCNRegPressure max(const GCNRegPressure &P1, const GCNRegPressure &P2)
unsigned getValueID() const
Return an ID for the concrete type of this object.
Definition: Value.h:463
virtual void verify(const MemorySSA *MSSA)
Definition: MemorySSA.h:1042
void unorderedDeleteIncomingValue(const MemoryAccess *MA)
Definition: MemorySSA.h:621
This class represents lattice values for constants.
Definition: AllocatorList.h:23
void unorderedDeleteIncomingIf(Fn &&Pred)
Definition: MemorySSA.h:602
Result(std::unique_ptr< MemorySSA > &&MSSA)
Definition: MemorySSA.h:925
AllAccessType::self_iterator getIterator()
Get the iterators for the all access list and the defs only list We default to the all access list...
Definition: MemorySSA.h:175
BasicBlock * getIncomingBlock(const Use &U) const
Return incoming basic block corresponding to an operand of the PHI.
Definition: MemorySSA.h:544
MemoryAccess * getDefiningAccess() const
Get the access that produces the memory state used by this Use.
Definition: MemorySSA.h:254
MemorySSAPrinterPass(raw_ostream &OS)
Definition: MemorySSA.h:940
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:64
void resetOptimized()
Definition: MemorySSA.h:346
const MemorySSA & getMSSA() const
Definition: MemorySSA.h:960
const AccessList * getBlockAccesses(const BasicBlock *BB) const
Return the list of MemoryAccess&#39;s for a given basic block.
Definition: MemorySSA.h:750
BasicBlock *const * const_block_iterator
Definition: MemorySSA.h:495
This provides a very simple, boring adaptor for a begin and end iterator into a range type...
MemoryAccess * getOptimized() const
Definition: MemorySSA.h:396
Extension point for the Value hierarchy.
Definition: DerivedUser.h:27
Represents a read-write access to memory, whether it is a must-alias, or a may-alias.
Definition: MemorySSA.h:372
BaseT::iterator::reference operator*() const
Definition: MemorySSA.h:1189
void setOptimized(MemoryAccess *)
Definition: MemorySSA.h:681
void deleteValue()
Delete a pointer to a generic Value.
Definition: Value.cpp:98
BasicBlock * getPhiArgBlock() const
Definition: MemorySSA.h:1089
memoryaccess_def_iterator defs_begin()
This iterator walks over all of the defs in a given MemoryAccess.
Definition: MemorySSA.h:1123
unsigned second
F(f)
int getBasicBlockIndex(const BasicBlock *BB) const
Return the first index of the specified basic block in the value list for this PHI.
Definition: MemorySSA.h:572
void(*)(DerivedUser *) DeleteValueTy
Definition: DerivedUser.h:29
This defines the Use class.
AllAccessType::const_self_iterator getIterator() const
Definition: MemorySSA.h:178
DefsOnlyType::self_iterator getDefsIterator()
Definition: MemorySSA.h:187
void setIncomingValue(unsigned I, MemoryAccess *V)
Definition: MemorySSA.h:531
A templated base class for SmallPtrSet which provides the typesafe interface that is common across al...
Definition: SmallPtrSet.h:343
MemoryPhi * getMemoryAccess(const BasicBlock *BB) const
Definition: MemorySSA.h:716
Represents read-only accesses to memory.
Definition: MemorySSA.h:316
This class is a batch walker of all MemoryUse&#39;s in the program, and points their defining access at t...
Definition: MemorySSA.cpp:1193
Legacy analysis pass which computes MemorySSA.
Definition: MemorySSA.h:951
Definition: BitVector.h:937
void resetOptimized()
Reset the ID of what this MemoryUse was optimized to, causing it to be rewalked by the walker if nece...
Definition: MemorySSA.h:688
void renamePass(BasicBlock *BB, MemoryAccess *IncomingVal, SmallPtrSetImpl< BasicBlock *> &Visited)
Definition: MemorySSA.h:813
block_iterator block_begin()
Definition: MemorySSA.h:497
A MemorySSAWalker that does AA walks to disambiguate accesses.
Definition: MemorySSA.cpp:972
A Use represents the edge between a Value definition and its users.
Definition: Use.h:55
Encapsulates MemorySSA, including all data associated with memory accesses.
Definition: MemorySSA.h:700
The access may reference the value stored in memory.
const DefsList * getBlockDefs(const BasicBlock *BB) const
Return the list of MemoryDef&#39;s and MemoryPhi&#39;s for a given basic block.
Definition: MemorySSA.h:758
const_block_iterator block_end() const
Definition: MemorySSA.h:510
bool isOptimized() const
Definition: MemorySSA.h:400
Walks the defining accesses of MemoryDefs.
Definition: MemorySSA.h:1257
def_chain_iterator & operator++()
Definition: MemorySSA.h:1265
bool isOptimized() const
Definition: MemorySSA.h:669
BaseT::iterator::pointer operator*() const
Definition: MemorySSA.h:1095
static bool classof(const Value *MA)
Definition: MemorySSA.h:387
iterator_range< block_iterator > blocks()
Definition: MemorySSA.h:514
A simple intrusive list implementation.
Definition: simple_ilist.h:78
Key
PAL metadata keys.
#define DEFINE_TRANSPARENT_OPERAND_ACCESSORS(CLASS, VALUECLASS)
Macro for generating out-of-class operand accessor definitions.
User * getUser() const LLVM_READONLY
Returns the User that contains this Use.
Definition: Use.cpp:40
static ChildIteratorType child_end(NodeRef N)
Definition: MemorySSA.h:1156
static int getID(struct InternalInstruction *insn, const void *miiArg)
MemoryUseOrDef * getMemoryAccess(const Instruction *I) const
Given a memory Mod/Ref&#39;ing instruction, get the MemorySSA access associated with it.
Definition: MemorySSA.h:712
MemoryAccess * getOptimized() const
Definition: MemorySSA.h:342
AllAccessType::const_reverse_self_iterator getReverseIterator() const
Definition: MemorySSA.h:184
upward_defs_iterator upward_defs_end()
Definition: MemorySSA.h:1236
std::unique_ptr< MemorySSA > MSSA
Definition: MemorySSA.h:929
void unorderedDeleteIncoming(unsigned I)
Definition: MemorySSA.h:586
A CRTP mix-in to automatically provide informational APIs needed for passes.
Definition: PassManager.h:365
This is the generic walker interface for walkers of MemorySSA.
Definition: MemorySSA.h:982
CRTP base class which implements the entire standard iterator facade in terms of a minimal subset of ...
Definition: iterator.h:67
Concrete subclass of DominatorTreeBase that is used to compute a normal dominator tree...
Definition: Dominators.h:144
op_range incoming_values()
Definition: MemorySSA.h:522
memoryaccess_def_iterator defs_end()
Definition: MemorySSA.h:1131
Analysis containing CSE Info
Definition: CSEInfo.cpp:20
unsigned getID() const
Definition: MemorySSA.h:632
MemoryAccess * getIncomingValue(unsigned I) const
Return incoming value number x.
Definition: MemorySSA.h:530
const_block_iterator block_begin() const
Definition: MemorySSA.h:502
An assembly annotator class to print Memory SSA information in comments.
Definition: MemorySSA.cpp:92
Use delete by default for iplist and ilist.
Definition: ilist.h:40
static bool runOnFunction(Function &F, bool PostInlining)
static Use * op_end(MemoryUseOrDef *MUD)
Definition: MemorySSA.h:432
static GCRegistry::Add< OcamlGC > B("ocaml", "ocaml 3.10-compatible GC")
void dump(const SparseBitVector< ElementSize > &LHS, raw_ostream &out)
A set of analyses that are preserved following a run of a transformation pass.
Definition: PassManager.h:153
DefsOnlyType::const_reverse_self_iterator getReverseDefsIterator() const
Definition: MemorySSA.h:196
AllAccessType::reverse_self_iterator getReverseIterator()
Definition: MemorySSA.h:181
LLVM Basic Block Representation.
Definition: BasicBlock.h:57
PointerIntPair - This class implements a pair of a pointer and small integer.
PHITransAddr - An address value which tracks and handles phi translation.
Definition: PHITransAddr.h:35
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:45
This is an important class for using LLVM in a threaded context.
Definition: LLVMContext.h:68
const_op_range incoming_values() const
Definition: MemorySSA.h:524
static GCRegistry::Add< CoreCLRGC > E("coreclr", "CoreCLR-compatible GC")
upward_defs_iterator & operator++()
Definition: MemorySSA.h:1196
void addIncoming(MemoryAccess *V, BasicBlock *BB)
Add an incoming value to the end of the PHI list.
Definition: MemorySSA.h:561
early cse Early CSE w MemorySSA
Definition: EarlyCSE.cpp:1308
A CRTP mix-in that provides informational APIs needed for analysis passes.
Definition: PassManager.h:382
static unsigned getIncomingValueNumForOperand(unsigned I)
Definition: MemorySSA.h:537
void setIncomingBlock(unsigned I, BasicBlock *BB)
Definition: MemorySSA.h:555
upward_defs_iterator(const MemoryAccessPair &Info)
Definition: MemorySSA.h:1174
InsertionPlace
Used in various insertion functions to specify whether we are talking about the beginning or end of a...
Definition: MemorySSA.h:780
Represent the analysis usage information of a pass.
iterator_range< def_chain_iterator< T, true > > optimized_def_chain(T MA)
Definition: MemorySSA.h:1296
void print(raw_ostream &OS) const
Definition: MemorySSA.cpp:2039
Printer pass for MemorySSA.
Definition: MemorySSA.h:936
static unsigned getOperandNumForIncomingValue(unsigned I)
Definition: MemorySSA.h:536
FunctionPass class - This class is used to implement most global optimizations.
Definition: Pass.h:284
static bool classof(const Value *MA)
Definition: MemorySSA.h:327
static void print(raw_ostream &Out, object::Archive::Kind Kind, T Val)
static unsigned operands(const MemoryUseOrDef *MUD)
Definition: MemorySSA.h:438
BasicBlock * getPhiArgBlock() const
Definition: MemorySSA.h:1205
virtual void invalidateInfo(MemoryAccess *)
Given a memory access, invalidate anything this walker knows about that access.
Definition: MemorySSA.h:1040
Iterator base class used to implement const and non-const iterators over the defining accesses of a M...
Definition: MemorySSA.h:127
#define DECLARE_TRANSPARENT_OPERAND_ACCESSORS(VALUECLASS)
Macro for generating in-class operand accessor declarations.
Provide an iterator that walks defs, giving both the memory access, and the current pointer location...
Definition: MemorySSA.h:1167
auto find(R &&Range, const T &Val) -> decltype(adl_begin(Range))
Provide wrappers to std::find which take ranges instead of having to pass begin/end explicitly...
Definition: STLExtras.h:1206
An intrusive list with ownership and callbacks specified/controlled by ilist_traits, only with API safe for polymorphic types.
Definition: ilist.h:388
MemoryAccess * getOptimized() const
Definition: MemorySSA.h:675
A MemorySSAWalker that does no alias queries, or anything else.
Definition: MemorySSA.h:1052
std::pair< const MemoryAccess *, MemoryLocation > ConstMemoryAccessPair
Definition: MemorySSA.h:1064
static void deleteNode(MemoryAccess *MA)
Definition: MemorySSA.h:229
unsigned first
bool operator==(const memoryaccess_def_iterator_base &Other) const
Definition: MemorySSA.h:1079
bool isOptimized() const
Definition: MemorySSA.h:338
The two locations may or may not alias. This is the least precise result.
Definition: AliasAnalysis.h:85
Representation for a specific memory location.
iterator_range< T > make_range(T x, T y)
Convenience function for iterating over sub-ranges.
void setDefiningAccess(MemoryAccess *DMA, bool Optimized=false, Optional< AliasResult > AR=MayAlias)
Definition: MemorySSA.h:296
Iterator for intrusive lists based on ilist_node.
static bool classof(const Value *V)
Definition: MemorySSA.h:626
SmallPtrSet - This class implements a set which is optimized for holding SmallSize or less elements...
Definition: SmallPtrSet.h:417
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:839
Module.h This file contains the declarations for the Module class.
An analysis that produces MemorySSA for a function.
Definition: MemorySSA.h:915
BasicBlock * getBlock() const
Definition: MemorySSA.h:156
void unorderedDeleteIncomingBlock(const BasicBlock *BB)
Definition: MemorySSA.h:614
MemoryUseOrDef(LLVMContext &C, MemoryAccess *DMA, unsigned Vty, DeleteValueTy DeleteValue, Instruction *MI, BasicBlock *BB, unsigned NumOperands)
Definition: MemorySSA.h:281
MemoryAccess * getLiveOnEntryDef() const
Definition: MemorySSA.h:734
Verifier pass for MemorySSA.
Definition: MemorySSA.h:946
A range adaptor for a pair of iterators.
MemoryPhi(LLVMContext &C, BasicBlock *BB, unsigned Ver, unsigned NumPreds=0)
Definition: MemorySSA.h:486
static Use * op_begin(MemoryUseOrDef *MUD)
Definition: MemorySSA.h:426
Class that has the common methods + fields of memory uses/defs.
Definition: MemorySSA.h:244
unsigned getNumIncomingValues() const
Return the number of incoming edges.
Definition: MemorySSA.h:527
BasicBlock * getIncomingBlock(unsigned I) const
Return incoming basic block number i.
Definition: MemorySSA.h:540
Instruction * getMemoryInst() const
Get the instruction that this MemoryUse represents.
Definition: MemorySSA.h:251
iterator_range< const_block_iterator > blocks() const
Definition: MemorySSA.h:518
user_iterator_impl< const User > const_user_iterator
Definition: Value.h:369
DefsOnlyType::const_self_iterator getDefsIterator() const
Definition: MemorySSA.h:190
void setOptimizedAccessType(Optional< AliasResult > AR)
Definition: MemorySSA.h:292
iterator_range< def_chain_iterator< T > > def_chain(T MA, MemoryAccess *UpTo=nullptr)
Definition: MemorySSA.h:1287
memoryaccess_def_iterator_base< MemoryAccess > memoryaccess_def_iterator
Definition: MemorySSA.h:128
block_iterator block_end()
Definition: MemorySSA.h:508
bool operator==(const def_chain_iterator &O) const
Definition: MemorySSA.h:1279
This file provides utility analysis objects describing memory locations.
#define I(x, y, z)
Definition: MD5.cpp:58
#define N
user_iterator_impl< User > user_iterator
Definition: Value.h:368
MemoryAccess * getIncomingValueForBlock(const BasicBlock *BB) const
Definition: MemorySSA.h:579
Compile-time customization of User operands.
Definition: User.h:42
MemoryAccess(LLVMContext &C, unsigned Vty, DeleteValueTy DeleteValue, BasicBlock *BB, unsigned NumOperands)
Definition: MemorySSA.h:215
LLVM_NODISCARD std::enable_if<!is_simple_type< Y >::value, typename cast_retty< X, const Y >::ret_type >::type dyn_cast(const Y &Val)
Definition: Casting.h:322
bool isLiveOnEntryDef(const MemoryAccess *MA) const
Return true if MA represents the live on entry value.
Definition: MemorySSA.h:730
Optional< AliasResult > getOptimizedAccessType() const
Definition: MemorySSA.h:268
raw_ostream & operator<<(raw_ostream &OS, const APInt &I)
Definition: APInt.h:2038
static ChildIteratorType child_begin(NodeRef N)
Definition: MemorySSA.h:1155
MemoryAccess * getClobberingMemoryAccess(const Instruction *I)
Given a memory Mod/Ref/ModRef&#39;ing instruction, calling this will give you the nearest dominating Memo...
Definition: MemorySSA.h:1011
static ChildIteratorType child_begin(NodeRef N)
Definition: MemorySSA.h:1146
static bool classof(const Value *MA)
Definition: MemorySSA.h:256
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
user_iterator user_begin()
Definition: Value.h:375
void setOptimized(MemoryAccess *MA)
Definition: MemorySSA.h:391
static NodeRef getEntryNode(NodeRef N)
Definition: MemorySSA.h:1145
LLVM Value Representation.
Definition: Value.h:72
MemoryDef(LLVMContext &C, MemoryAccess *DMA, Instruction *MI, BasicBlock *BB, unsigned Ver)
Definition: MemorySSA.h:378
DefsOnlyType::reverse_self_iterator getReverseDefsIterator()
Definition: MemorySSA.h:193
upward_defs_iterator upward_defs_begin(const MemoryAccessPair &Pair)
Definition: MemorySSA.h:1232
HungoffOperandTraits - determine the allocation regime of the Use array when it is not a prefix to th...
Definition: OperandTraits.h:95
void allocHungoffUses(unsigned N, bool IsPhi=false)
Allocate the array of Uses, followed by a pointer (with bottom bit set) to the User.
Definition: User.cpp:39
unsigned getID() const
Used for debugging and tracking things about MemoryAccesses.
Definition: MemorySSA.h:661
This class implements an extremely fast bulk output stream that can only output to a stream...
Definition: raw_ostream.h:45
const_user_iterator const_iterator
Definition: MemorySSA.h:163
IRTranslator LLVM IR MI
FixedNumOperandTraits - determine the allocation regime of the Use array when it is a prefix to the U...
Definition: OperandTraits.h:30
A container for analyses that lazily runs them and caches their results.
void setBlock(BasicBlock *BB)
Used by MemorySSA to change the block of a MemoryAccess when it is moved.
Definition: MemorySSA.h:209
MemoryUse(LLVMContext &C, MemoryAccess *DMA, Instruction *MI, BasicBlock *BB)
Definition: MemorySSA.h:320
static bool classof(const Value *V)
Definition: MemorySSA.h:151
iterator_range< upward_defs_iterator > upward_defs(const MemoryAccessPair &Pair)
Definition: MemorySSA.h:1239
Represents phi nodes for memory accesses.
Definition: MemorySSA.h:478
unsigned getID() const
Definition: MemorySSA.h:411
static ChildIteratorType child_end(NodeRef N)
Definition: MemorySSA.h:1147
DefsList * getWritableBlockDefs(const BasicBlock *BB) const
Definition: MemorySSA.h:800
user_iterator iterator
The user iterators for a memory access.
Definition: MemorySSA.h:162
memoryaccess_def_iterator_base< const MemoryAccess > const_memoryaccess_def_iterator
Definition: MemorySSA.h:130
bool operator==(const upward_defs_iterator &Other) const
Definition: MemorySSA.h:1185
A special type used by analysis passes to provide an address that identifies that particular analysis...
Definition: PassManager.h:70
void resetOptimized()
Definition: MemorySSA.h:404
void setOptimized(MemoryAccess *DMA)
Definition: MemorySSA.h:333
std::pair< MemoryAccess *, MemoryLocation > MemoryAccessPair
Definition: MemorySSA.h:1063
void allocHungoffUses(unsigned N)
this is more complicated than the generic User::allocHungoffUses, because we have to allocate Uses fo...
Definition: MemorySSA.h:640
user_iterator user_end()
Definition: Value.h:383