LLVM  8.0.0svn
MemorySSA.h
Go to the documentation of this file.
1 //===- MemorySSA.h - Build Memory SSA ---------------------------*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 /// \file
11 /// This file exposes an interface to building/using memory SSA to
12 /// walk memory instructions using a use/def graph.
13 ///
14 /// Memory SSA class builds an SSA form that links together memory access
15 /// instructions such as loads, stores, atomics, and calls. Additionally, it
16 /// does a trivial form of "heap versioning" Every time the memory state changes
17 /// in the program, we generate a new heap version. It generates
18 /// MemoryDef/Uses/Phis that are overlayed on top of the existing instructions.
19 ///
20 /// As a trivial example,
21 /// define i32 @main() #0 {
22 /// entry:
23 /// %call = call noalias i8* @_Znwm(i64 4) #2
24 /// %0 = bitcast i8* %call to i32*
25 /// %call1 = call noalias i8* @_Znwm(i64 4) #2
26 /// %1 = bitcast i8* %call1 to i32*
27 /// store i32 5, i32* %0, align 4
28 /// store i32 7, i32* %1, align 4
29 /// %2 = load i32* %0, align 4
30 /// %3 = load i32* %1, align 4
31 /// %add = add nsw i32 %2, %3
32 /// ret i32 %add
33 /// }
34 ///
35 /// Will become
36 /// define i32 @main() #0 {
37 /// entry:
38 /// ; 1 = MemoryDef(0)
39 /// %call = call noalias i8* @_Znwm(i64 4) #3
40 /// %2 = bitcast i8* %call to i32*
41 /// ; 2 = MemoryDef(1)
42 /// %call1 = call noalias i8* @_Znwm(i64 4) #3
43 /// %4 = bitcast i8* %call1 to i32*
44 /// ; 3 = MemoryDef(2)
45 /// store i32 5, i32* %2, align 4
46 /// ; 4 = MemoryDef(3)
47 /// store i32 7, i32* %4, align 4
48 /// ; MemoryUse(3)
49 /// %7 = load i32* %2, align 4
50 /// ; MemoryUse(4)
51 /// %8 = load i32* %4, align 4
52 /// %add = add nsw i32 %7, %8
53 /// ret i32 %add
54 /// }
55 ///
56 /// Given this form, all the stores that could ever effect the load at %8 can be
57 /// gotten by using the MemoryUse associated with it, and walking from use to
58 /// def until you hit the top of the function.
59 ///
60 /// Each def also has a list of users associated with it, so you can walk from
61 /// both def to users, and users to defs. Note that we disambiguate MemoryUses,
62 /// but not the RHS of MemoryDefs. You can see this above at %7, which would
63 /// otherwise be a MemoryUse(4). Being disambiguated means that for a given
64 /// store, all the MemoryUses on its use lists are may-aliases of that store
65 /// (but the MemoryDefs on its use list may not be).
66 ///
67 /// MemoryDefs are not disambiguated because it would require multiple reaching
68 /// definitions, which would require multiple phis, and multiple memoryaccesses
69 /// per instruction.
70 //
71 //===----------------------------------------------------------------------===//
72 
73 #ifndef LLVM_ANALYSIS_MEMORYSSA_H
74 #define LLVM_ANALYSIS_MEMORYSSA_H
75 
76 #include "llvm/ADT/DenseMap.h"
77 #include "llvm/ADT/GraphTraits.h"
78 #include "llvm/ADT/SmallPtrSet.h"
79 #include "llvm/ADT/SmallVector.h"
80 #include "llvm/ADT/ilist.h"
81 #include "llvm/ADT/ilist_node.h"
82 #include "llvm/ADT/iterator.h"
84 #include "llvm/ADT/simple_ilist.h"
88 #include "llvm/IR/BasicBlock.h"
89 #include "llvm/IR/DerivedUser.h"
90 #include "llvm/IR/Dominators.h"
91 #include "llvm/IR/Module.h"
92 #include "llvm/IR/Type.h"
93 #include "llvm/IR/Use.h"
94 #include "llvm/IR/User.h"
95 #include "llvm/IR/Value.h"
96 #include "llvm/IR/ValueHandle.h"
97 #include "llvm/Pass.h"
98 #include "llvm/Support/Casting.h"
99 #include <algorithm>
100 #include <cassert>
101 #include <cstddef>
102 #include <iterator>
103 #include <memory>
104 #include <utility>
105 
106 namespace llvm {
107 
108 class Function;
109 class Instruction;
110 class MemoryAccess;
111 class MemorySSAWalker;
112 class LLVMContext;
113 class raw_ostream;
114 
115 namespace MSSAHelpers {
116 
117 struct AllAccessTag {};
118 struct DefsOnlyTag {};
119 
120 } // end namespace MSSAHelpers
121 
122 enum : unsigned {
123  // Used to signify what the default invalid ID is for MemoryAccess's
124  // getID()
126 };
127 
128 template <class T> class memoryaccess_def_iterator_base;
132 
133 // The base for all memory accesses. All memory accesses in a block are
134 // linked together using an intrusive list.
136  : public DerivedUser,
137  public ilist_node<MemoryAccess, ilist_tag<MSSAHelpers::AllAccessTag>>,
138  public ilist_node<MemoryAccess, ilist_tag<MSSAHelpers::DefsOnlyTag>> {
139 public:
140  using AllAccessType =
142  using DefsOnlyType =
144 
145  MemoryAccess(const MemoryAccess &) = delete;
146  MemoryAccess &operator=(const MemoryAccess &) = delete;
147 
148  void *operator new(size_t) = delete;
149 
150  // Methods for support type inquiry through isa, cast, and
151  // dyn_cast
152  static bool classof(const Value *V) {
153  unsigned ID = V->getValueID();
154  return ID == MemoryUseVal || ID == MemoryPhiVal || ID == MemoryDefVal;
155  }
156 
157  BasicBlock *getBlock() const { return Block; }
158 
159  void print(raw_ostream &OS) const;
160  void dump() const;
161 
162  /// The user iterators for a memory access
165 
166  /// This iterator walks over all of the defs in a given
167  /// MemoryAccess. For MemoryPhi nodes, this walks arguments. For
168  /// MemoryUse/MemoryDef, this walks the defining access.
169  memoryaccess_def_iterator defs_begin();
170  const_memoryaccess_def_iterator defs_begin() const;
171  memoryaccess_def_iterator defs_end();
172  const_memoryaccess_def_iterator defs_end() const;
173 
174  /// Get the iterators for the all access list and the defs only list
175  /// We default to the all access list.
177  return this->AllAccessType::getIterator();
178  }
180  return this->AllAccessType::getIterator();
181  }
183  return this->AllAccessType::getReverseIterator();
184  }
186  return this->AllAccessType::getReverseIterator();
187  }
189  return this->DefsOnlyType::getIterator();
190  }
192  return this->DefsOnlyType::getIterator();
193  }
195  return this->DefsOnlyType::getReverseIterator();
196  }
198  return this->DefsOnlyType::getReverseIterator();
199  }
200 
201 protected:
202  friend class MemoryDef;
203  friend class MemoryPhi;
204  friend class MemorySSA;
205  friend class MemoryUse;
206  friend class MemoryUseOrDef;
207 
208  /// Used by MemorySSA to change the block of a MemoryAccess when it is
209  /// moved.
210  void setBlock(BasicBlock *BB) { Block = BB; }
211 
212  /// Used for debugging and tracking things about MemoryAccesses.
213  /// Guaranteed unique among MemoryAccesses, no guarantees otherwise.
214  inline unsigned getID() const;
215 
216  MemoryAccess(LLVMContext &C, unsigned Vty, DeleteValueTy DeleteValue,
217  BasicBlock *BB, unsigned NumOperands)
218  : DerivedUser(Type::getVoidTy(C), Vty, nullptr, NumOperands, DeleteValue),
219  Block(BB) {}
220 
221  // Use deleteValue() to delete a generic MemoryAccess.
222  ~MemoryAccess() = default;
223 
224 private:
225  BasicBlock *Block;
226 };
227 
228 template <>
230  static void deleteNode(MemoryAccess *MA) { MA->deleteValue(); }
231 };
232 
234  MA.print(OS);
235  return OS;
236 }
237 
238 /// Class that has the common methods + fields of memory uses/defs. It's
239 /// a little awkward to have, but there are many cases where we want either a
240 /// use or def, and there are many cases where uses are needed (defs aren't
241 /// acceptable), and vice-versa.
242 ///
243 /// This class should never be instantiated directly; make a MemoryUse or
244 /// MemoryDef instead.
245 class MemoryUseOrDef : public MemoryAccess {
246 public:
247  void *operator new(size_t) = delete;
248 
250 
251  /// Get the instruction that this MemoryUse represents.
252  Instruction *getMemoryInst() const { return MemoryInstruction; }
253 
254  /// Get the access that produces the memory state used by this Use.
255  MemoryAccess *getDefiningAccess() const { return getOperand(0); }
256 
257  static bool classof(const Value *MA) {
258  return MA->getValueID() == MemoryUseVal || MA->getValueID() == MemoryDefVal;
259  }
260 
261  // Sadly, these have to be public because they are needed in some of the
262  // iterators.
263  inline bool isOptimized() const;
264  inline MemoryAccess *getOptimized() const;
265  inline void setOptimized(MemoryAccess *);
266 
267  // Retrieve AliasResult type of the optimized access. Ideally this would be
268  // returned by the caching walker and may go away in the future.
270  return OptimizedAccessAlias;
271  }
272 
273  /// Reset the ID of what this MemoryUse was optimized to, causing it to
274  /// be rewalked by the walker if necessary.
275  /// This really should only be called by tests.
276  inline void resetOptimized();
277 
278 protected:
279  friend class MemorySSA;
280  friend class MemorySSAUpdater;
281 
282  MemoryUseOrDef(LLVMContext &C, MemoryAccess *DMA, unsigned Vty,
283  DeleteValueTy DeleteValue, Instruction *MI, BasicBlock *BB,
284  unsigned NumOperands)
285  : MemoryAccess(C, Vty, DeleteValue, BB, NumOperands),
286  MemoryInstruction(MI), OptimizedAccessAlias(MayAlias) {
287  setDefiningAccess(DMA);
288  }
289 
290  // Use deleteValue() to delete a generic MemoryUseOrDef.
291  ~MemoryUseOrDef() = default;
292 
294  OptimizedAccessAlias = AR;
295  }
296 
297  void setDefiningAccess(MemoryAccess *DMA, bool Optimized = false,
299  if (!Optimized) {
300  setOperand(0, DMA);
301  return;
302  }
303  setOptimized(DMA);
304  setOptimizedAccessType(AR);
305  }
306 
307 private:
308  Instruction *MemoryInstruction;
309  Optional<AliasResult> OptimizedAccessAlias;
310 };
311 
312 /// Represents read-only accesses to memory
313 ///
314 /// In particular, the set of Instructions that will be represented by
315 /// MemoryUse's is exactly the set of Instructions for which
316 /// AliasAnalysis::getModRefInfo returns "Ref".
317 class MemoryUse final : public MemoryUseOrDef {
318 public:
320 
322  : MemoryUseOrDef(C, DMA, MemoryUseVal, deleteMe, MI, BB,
323  /*NumOperands=*/1) {}
324 
325  // allocate space for exactly one operand
326  void *operator new(size_t s) { return User::operator new(s, 1); }
327 
328  static bool classof(const Value *MA) {
329  return MA->getValueID() == MemoryUseVal;
330  }
331 
332  void print(raw_ostream &OS) const;
333 
335  OptimizedID = DMA->getID();
336  setOperand(0, DMA);
337  }
338 
339  bool isOptimized() const {
340  return getDefiningAccess() && OptimizedID == getDefiningAccess()->getID();
341  }
342 
344  return getDefiningAccess();
345  }
346 
347  void resetOptimized() {
348  OptimizedID = INVALID_MEMORYACCESS_ID;
349  }
350 
351 protected:
352  friend class MemorySSA;
353 
354 private:
355  static void deleteMe(DerivedUser *Self);
356 
357  unsigned OptimizedID = INVALID_MEMORYACCESS_ID;
358 };
359 
360 template <>
361 struct OperandTraits<MemoryUse> : public FixedNumOperandTraits<MemoryUse, 1> {};
363 
364 /// Represents a read-write access to memory, whether it is a must-alias,
365 /// or a may-alias.
366 ///
367 /// In particular, the set of Instructions that will be represented by
368 /// MemoryDef's is exactly the set of Instructions for which
369 /// AliasAnalysis::getModRefInfo returns "Mod" or "ModRef".
370 /// Note that, in order to provide def-def chains, all defs also have a use
371 /// associated with them. This use points to the nearest reaching
372 /// MemoryDef/MemoryPhi.
373 class MemoryDef final : public MemoryUseOrDef {
374 public:
375  friend class MemorySSA;
376 
378 
380  unsigned Ver)
381  : MemoryUseOrDef(C, DMA, MemoryDefVal, deleteMe, MI, BB,
382  /*NumOperands=*/2),
383  ID(Ver) {}
384 
385  // allocate space for exactly two operands
386  void *operator new(size_t s) { return User::operator new(s, 2); }
387 
388  static bool classof(const Value *MA) {
389  return MA->getValueID() == MemoryDefVal;
390  }
391 
393  setOperand(1, MA);
394  OptimizedID = MA->getID();
395  }
396 
398  return cast_or_null<MemoryAccess>(getOperand(1));
399  }
400 
401  bool isOptimized() const {
402  return getOptimized() && OptimizedID == getOptimized()->getID();
403  }
404 
405  void resetOptimized() {
406  OptimizedID = INVALID_MEMORYACCESS_ID;
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 
707  /// Given a memory Mod/Ref'ing instruction, get the MemorySSA
708  /// access associated with it. If passed a basic block gets the memory phi
709  /// node that exists for that block, if there is one. Otherwise, this will get
710  /// a MemoryUseOrDef.
712  return cast_or_null<MemoryUseOrDef>(ValueToMemoryAccess.lookup(I));
713  }
714 
715  MemoryPhi *getMemoryAccess(const BasicBlock *BB) const {
716  return cast_or_null<MemoryPhi>(ValueToMemoryAccess.lookup(cast<Value>(BB)));
717  }
718 
719  void dump() const;
720  void print(raw_ostream &) const;
721 
722  /// Return true if \p MA represents the live on entry value
723  ///
724  /// Loads and stores from pointer arguments and other global values may be
725  /// defined by memory operations that do not occur in the current function, so
726  /// they may be live on entry to the function. MemorySSA represents such
727  /// memory state by the live on entry definition, which is guaranteed to occur
728  /// before any other memory access in the function.
729  inline bool isLiveOnEntryDef(const MemoryAccess *MA) const {
730  return MA == LiveOnEntryDef.get();
731  }
732 
733  inline MemoryAccess *getLiveOnEntryDef() const {
734  return LiveOnEntryDef.get();
735  }
736 
737  // Sadly, iplists, by default, owns and deletes pointers added to the
738  // list. It's not currently possible to have two iplists for the same type,
739  // where one owns the pointers, and one does not. This is because the traits
740  // are per-type, not per-tag. If this ever changes, we should make the
741  // DefList an iplist.
743  using DefsList =
745 
746  /// Return the list of MemoryAccess's for a given basic block.
747  ///
748  /// This list is not modifiable by the user.
749  const AccessList *getBlockAccesses(const BasicBlock *BB) const {
750  return getWritableBlockAccesses(BB);
751  }
752 
753  /// Return the list of MemoryDef's and MemoryPhi's for a given basic
754  /// block.
755  ///
756  /// This list is not modifiable by the user.
757  const DefsList *getBlockDefs(const BasicBlock *BB) const {
758  return getWritableBlockDefs(BB);
759  }
760 
761  /// Given two memory accesses in the same basic block, determine
762  /// whether MemoryAccess \p A dominates MemoryAccess \p B.
763  bool locallyDominates(const MemoryAccess *A, const MemoryAccess *B) const;
764 
765  /// Given two memory accesses in potentially different blocks,
766  /// determine whether MemoryAccess \p A dominates MemoryAccess \p B.
767  bool dominates(const MemoryAccess *A, const MemoryAccess *B) const;
768 
769  /// Given a MemoryAccess and a Use, determine whether MemoryAccess \p A
770  /// dominates Use \p B.
771  bool dominates(const MemoryAccess *A, const Use &B) const;
772 
773  /// Verify that MemorySSA is self consistent (IE definitions dominate
774  /// all uses, uses appear in the right places). This is used by unit tests.
775  void verifyMemorySSA() const;
776 
777  /// Check clobber sanity for an access.
778  void checkClobberSanityAccess(const MemoryAccess *MA) const;
779 
780  /// Used in various insertion functions to specify whether we are talking
781  /// about the beginning or end of a block.
782  enum InsertionPlace { Beginning, End };
783 
784 protected:
785  // Used by Memory SSA annotater, dumpers, and wrapper pass
788  friend class MemorySSAUpdater;
789 
790  void verifyDefUses(Function &F) const;
791  void verifyDomination(Function &F) const;
792  void verifyOrdering(Function &F) const;
793  void verifyDominationNumbers(const Function &F) const;
794  void verifyClobberSanity(const Function &F) const;
795 
796  // This is used by the use optimizer and updater.
798  auto It = PerBlockAccesses.find(BB);
799  return It == PerBlockAccesses.end() ? nullptr : It->second.get();
800  }
801 
802  // This is used by the use optimizer and updater.
804  auto It = PerBlockDefs.find(BB);
805  return It == PerBlockDefs.end() ? nullptr : It->second.get();
806  }
807 
808  // These is used by the updater to perform various internal MemorySSA
809  // machinsations. They do not always leave the IR in a correct state, and
810  // relies on the updater to fixup what it breaks, so it is not public.
811 
812  void moveTo(MemoryUseOrDef *What, BasicBlock *BB, AccessList::iterator Where);
813  void moveTo(MemoryAccess *What, BasicBlock *BB, InsertionPlace Point);
814 
815  // Rename the dominator tree branch rooted at BB.
816  void renamePass(BasicBlock *BB, MemoryAccess *IncomingVal,
818  renamePass(DT->getNode(BB), IncomingVal, Visited, true, true);
819  }
820 
821  void removeFromLookups(MemoryAccess *);
822  void removeFromLists(MemoryAccess *, bool ShouldDelete = true);
823  void insertIntoListsForBlock(MemoryAccess *, const BasicBlock *,
825  void insertIntoListsBefore(MemoryAccess *, const BasicBlock *,
826  AccessList::iterator);
827  MemoryUseOrDef *createDefinedAccess(Instruction *, MemoryAccess *,
828  const MemoryUseOrDef *Template = nullptr);
829 
830 private:
831  class CachingWalker;
832  class OptimizeUses;
833 
834  CachingWalker *getWalkerImpl();
835  void buildMemorySSA();
836  void optimizeUses();
837 
838  void prepareForMoveTo(MemoryAccess *, BasicBlock *);
839  void verifyUseInDefs(MemoryAccess *, MemoryAccess *) const;
840 
843 
844  void
845  determineInsertionPoint(const SmallPtrSetImpl<BasicBlock *> &DefiningBlocks);
846  void markUnreachableAsLiveOnEntry(BasicBlock *BB);
847  bool dominatesUse(const MemoryAccess *, const MemoryAccess *) const;
848  MemoryPhi *createMemoryPhi(BasicBlock *BB);
849  MemoryUseOrDef *createNewAccess(Instruction *,
850  const MemoryUseOrDef *Template = nullptr);
851  MemoryAccess *findDominatingDef(BasicBlock *, enum InsertionPlace);
852  void placePHINodes(const SmallPtrSetImpl<BasicBlock *> &);
853  MemoryAccess *renameBlock(BasicBlock *, MemoryAccess *, bool);
854  void renameSuccessorPhis(BasicBlock *, MemoryAccess *, bool);
855  void renamePass(DomTreeNode *, MemoryAccess *IncomingVal,
857  bool SkipVisited = false, bool RenameAllUses = false);
858  AccessList *getOrCreateAccessList(const BasicBlock *);
859  DefsList *getOrCreateDefsList(const BasicBlock *);
860  void renumberBlock(const BasicBlock *) const;
861  AliasAnalysis *AA;
862  DominatorTree *DT;
863  Function &F;
864 
865  // Memory SSA mappings
866  DenseMap<const Value *, MemoryAccess *> ValueToMemoryAccess;
867 
868  // These two mappings contain the main block to access/def mappings for
869  // MemorySSA. The list contained in PerBlockAccesses really owns all the
870  // MemoryAccesses.
871  // Both maps maintain the invariant that if a block is found in them, the
872  // corresponding list is not empty, and if a block is not found in them, the
873  // corresponding list is empty.
874  AccessMap PerBlockAccesses;
875  DefsMap PerBlockDefs;
876  std::unique_ptr<MemoryAccess, ValueDeleter> LiveOnEntryDef;
877 
878  // Domination mappings
879  // Note that the numbering is local to a block, even though the map is
880  // global.
881  mutable SmallPtrSet<const BasicBlock *, 16> BlockNumberingValid;
882  mutable DenseMap<const MemoryAccess *, unsigned long> BlockNumbering;
883 
884  // Memory SSA building info
885  std::unique_ptr<CachingWalker> Walker;
886  unsigned NextID;
887 };
888 
889 // Internal MemorySSA utils, for use by MemorySSA classes and walkers
891 protected:
892  friend class GVNHoist;
893  friend class MemorySSAWalker;
894 
895  // This function should not be used by new passes.
896  static bool defClobbersUseOrDef(MemoryDef *MD, const MemoryUseOrDef *MU,
897  AliasAnalysis &AA);
898 };
899 
900 // This pass does eager building and then printing of MemorySSA. It is used by
901 // the tests to be able to build, dump, and verify Memory SSA.
903 public:
905 
906  bool runOnFunction(Function &) override;
907  void getAnalysisUsage(AnalysisUsage &AU) const override;
908 
909  static char ID;
910 };
911 
912 /// An analysis that produces \c MemorySSA for a function.
913 ///
914 class MemorySSAAnalysis : public AnalysisInfoMixin<MemorySSAAnalysis> {
916 
917  static AnalysisKey Key;
918 
919 public:
920  // Wrap MemorySSA result to ensure address stability of internal MemorySSA
921  // pointers after construction. Use a wrapper class instead of plain
922  // unique_ptr<MemorySSA> to avoid build breakage on MSVC.
923  struct Result {
924  Result(std::unique_ptr<MemorySSA> &&MSSA) : MSSA(std::move(MSSA)) {}
925 
926  MemorySSA &getMSSA() { return *MSSA.get(); }
927 
928  std::unique_ptr<MemorySSA> MSSA;
929  };
930 
932 };
933 
934 /// Printer pass for \c MemorySSA.
935 class MemorySSAPrinterPass : public PassInfoMixin<MemorySSAPrinterPass> {
936  raw_ostream &OS;
937 
938 public:
939  explicit MemorySSAPrinterPass(raw_ostream &OS) : OS(OS) {}
940 
942 };
943 
944 /// Verifier pass for \c MemorySSA.
945 struct MemorySSAVerifierPass : PassInfoMixin<MemorySSAVerifierPass> {
947 };
948 
949 /// Legacy analysis pass which computes \c MemorySSA.
951 public:
953 
954  static char ID;
955 
956  bool runOnFunction(Function &) override;
957  void releaseMemory() override;
958  MemorySSA &getMSSA() { return *MSSA; }
959  const MemorySSA &getMSSA() const { return *MSSA; }
960 
961  void getAnalysisUsage(AnalysisUsage &AU) const override;
962 
963  void verifyAnalysis() const override;
964  void print(raw_ostream &OS, const Module *M = nullptr) const override;
965 
966 private:
967  std::unique_ptr<MemorySSA> MSSA;
968 };
969 
970 /// This is the generic walker interface for walkers of MemorySSA.
971 /// Walkers are used to be able to further disambiguate the def-use chains
972 /// MemorySSA gives you, or otherwise produce better info than MemorySSA gives
973 /// you.
974 /// In particular, while the def-use chains provide basic information, and are
975 /// guaranteed to give, for example, the nearest may-aliasing MemoryDef for a
976 /// MemoryUse as AliasAnalysis considers it, a user mant want better or other
977 /// information. In particular, they may want to use SCEV info to further
978 /// disambiguate memory accesses, or they may want the nearest dominating
979 /// may-aliasing MemoryDef for a call or a store. This API enables a
980 /// standardized interface to getting and using that info.
982 public:
984  virtual ~MemorySSAWalker() = default;
985 
987 
988  /// Given a memory Mod/Ref/ModRef'ing instruction, calling this
989  /// will give you the nearest dominating MemoryAccess that Mod's the location
990  /// the instruction accesses (by skipping any def which AA can prove does not
991  /// alias the location(s) accessed by the instruction given).
992  ///
993  /// Note that this will return a single access, and it must dominate the
994  /// Instruction, so if an operand of a MemoryPhi node Mod's the instruction,
995  /// this will return the MemoryPhi, not the operand. This means that
996  /// given:
997  /// if (a) {
998  /// 1 = MemoryDef(liveOnEntry)
999  /// store %a
1000  /// } else {
1001  /// 2 = MemoryDef(liveOnEntry)
1002  /// store %b
1003  /// }
1004  /// 3 = MemoryPhi(2, 1)
1005  /// MemoryUse(3)
1006  /// load %a
1007  ///
1008  /// calling this API on load(%a) will return the MemoryPhi, not the MemoryDef
1009  /// in the if (a) branch.
1011  MemoryAccess *MA = MSSA->getMemoryAccess(I);
1012  assert(MA && "Handed an instruction that MemorySSA doesn't recognize?");
1013  return getClobberingMemoryAccess(MA);
1014  }
1015 
1016  /// Does the same thing as getClobberingMemoryAccess(const Instruction *I),
1017  /// but takes a MemoryAccess instead of an Instruction.
1018  virtual MemoryAccess *getClobberingMemoryAccess(MemoryAccess *) = 0;
1019 
1020  /// Given a potentially clobbering memory access and a new location,
1021  /// calling this will give you the nearest dominating clobbering MemoryAccess
1022  /// (by skipping non-aliasing def links).
1023  ///
1024  /// This version of the function is mainly used to disambiguate phi translated
1025  /// pointers, where the value of a pointer may have changed from the initial
1026  /// memory access. Note that this expects to be handed either a MemoryUse,
1027  /// or an already potentially clobbering access. Unlike the above API, if
1028  /// given a MemoryDef that clobbers the pointer as the starting access, it
1029  /// will return that MemoryDef, whereas the above would return the clobber
1030  /// starting from the use side of the memory def.
1031  virtual MemoryAccess *getClobberingMemoryAccess(MemoryAccess *,
1032  const MemoryLocation &) = 0;
1033 
1034  /// Given a memory access, invalidate anything this walker knows about
1035  /// that access.
1036  /// This API is used by walkers that store information to perform basic cache
1037  /// invalidation. This will be called by MemorySSA at appropriate times for
1038  /// the walker it uses or returns.
1039  virtual void invalidateInfo(MemoryAccess *) {}
1040 
1041  virtual void verify(const MemorySSA *MSSA) { assert(MSSA == this->MSSA); }
1042 
1043 protected:
1044  friend class MemorySSA; // For updating MSSA pointer in MemorySSA move
1045  // constructor.
1047 };
1048 
1049 /// A MemorySSAWalker that does no alias queries, or anything else. It
1050 /// simply returns the links as they were constructed by the builder.
1052 public:
1053  // Keep the overrides below from hiding the Instruction overload of
1054  // getClobberingMemoryAccess.
1056 
1057  MemoryAccess *getClobberingMemoryAccess(MemoryAccess *) override;
1058  MemoryAccess *getClobberingMemoryAccess(MemoryAccess *,
1059  const MemoryLocation &) override;
1060 };
1061 
1062 using MemoryAccessPair = std::pair<MemoryAccess *, MemoryLocation>;
1063 using ConstMemoryAccessPair = std::pair<const MemoryAccess *, MemoryLocation>;
1064 
1065 /// Iterator base class used to implement const and non-const iterators
1066 /// over the defining accesses of a MemoryAccess.
1067 template <class T>
1069  : public iterator_facade_base<memoryaccess_def_iterator_base<T>,
1070  std::forward_iterator_tag, T, ptrdiff_t, T *,
1071  T *> {
1072  using BaseT = typename memoryaccess_def_iterator_base::iterator_facade_base;
1073 
1074 public:
1075  memoryaccess_def_iterator_base(T *Start) : Access(Start) {}
1076  memoryaccess_def_iterator_base() = default;
1077 
1078  bool operator==(const memoryaccess_def_iterator_base &Other) const {
1079  return Access == Other.Access && (!Access || ArgNo == Other.ArgNo);
1080  }
1081 
1082  // This is a bit ugly, but for MemoryPHI's, unlike PHINodes, you can't get the
1083  // block from the operand in constant time (In a PHINode, the uselist has
1084  // both, so it's just subtraction). We provide it as part of the
1085  // iterator to avoid callers having to linear walk to get the block.
1086  // If the operation becomes constant time on MemoryPHI's, this bit of
1087  // abstraction breaking should be removed.
1089  MemoryPhi *MP = dyn_cast<MemoryPhi>(Access);
1090  assert(MP && "Tried to get phi arg block when not iterating over a PHI");
1091  return MP->getIncomingBlock(ArgNo);
1092  }
1093 
1094  typename BaseT::iterator::pointer operator*() const {
1095  assert(Access && "Tried to access past the end of our iterator");
1096  // Go to the first argument for phis, and the defining access for everything
1097  // else.
1098  if (MemoryPhi *MP = dyn_cast<MemoryPhi>(Access))
1099  return MP->getIncomingValue(ArgNo);
1100  return cast<MemoryUseOrDef>(Access)->getDefiningAccess();
1101  }
1102 
1103  using BaseT::operator++;
1105  assert(Access && "Hit end of iterator");
1106  if (MemoryPhi *MP = dyn_cast<MemoryPhi>(Access)) {
1107  if (++ArgNo >= MP->getNumIncomingValues()) {
1108  ArgNo = 0;
1109  Access = nullptr;
1110  }
1111  } else {
1112  Access = nullptr;
1113  }
1114  return *this;
1115  }
1116 
1117 private:
1118  T *Access = nullptr;
1119  unsigned ArgNo = 0;
1120 };
1121 
1123  return memoryaccess_def_iterator(this);
1124 }
1125 
1127  return const_memoryaccess_def_iterator(this);
1128 }
1129 
1131  return memoryaccess_def_iterator();
1132 }
1133 
1136 }
1137 
1138 /// GraphTraits for a MemoryAccess, which walks defs in the normal case,
1139 /// and uses in the inverse case.
1140 template <> struct GraphTraits<MemoryAccess *> {
1143 
1144  static NodeRef getEntryNode(NodeRef N) { return N; }
1146  static ChildIteratorType child_end(NodeRef N) { return N->defs_end(); }
1147 };
1148 
1149 template <> struct GraphTraits<Inverse<MemoryAccess *>> {
1152 
1153  static NodeRef getEntryNode(NodeRef N) { return N; }
1155  static ChildIteratorType child_end(NodeRef N) { return N->user_end(); }
1156 };
1157 
1158 /// Provide an iterator that walks defs, giving both the memory access,
1159 /// and the current pointer location, updating the pointer location as it
1160 /// changes due to phi node translation.
1161 ///
1162 /// This iterator, while somewhat specialized, is what most clients actually
1163 /// want when walking upwards through MemorySSA def chains. It takes a pair of
1164 /// <MemoryAccess,MemoryLocation>, and walks defs, properly translating the
1165 /// memory location through phi nodes for the user.
1167  : public iterator_facade_base<upward_defs_iterator,
1168  std::forward_iterator_tag,
1169  const MemoryAccessPair> {
1170  using BaseT = upward_defs_iterator::iterator_facade_base;
1171 
1172 public:
1174  : DefIterator(Info.first), Location(Info.second),
1175  OriginalAccess(Info.first) {
1176  CurrentPair.first = nullptr;
1177 
1178  WalkingPhi = Info.first && isa<MemoryPhi>(Info.first);
1179  fillInCurrentPair();
1180  }
1181 
1182  upward_defs_iterator() { CurrentPair.first = nullptr; }
1183 
1184  bool operator==(const upward_defs_iterator &Other) const {
1185  return DefIterator == Other.DefIterator;
1186  }
1187 
1188  BaseT::iterator::reference operator*() const {
1189  assert(DefIterator != OriginalAccess->defs_end() &&
1190  "Tried to access past the end of our iterator");
1191  return CurrentPair;
1192  }
1193 
1194  using BaseT::operator++;
1196  assert(DefIterator != OriginalAccess->defs_end() &&
1197  "Tried to access past the end of the iterator");
1198  ++DefIterator;
1199  if (DefIterator != OriginalAccess->defs_end())
1200  fillInCurrentPair();
1201  return *this;
1202  }
1203 
1204  BasicBlock *getPhiArgBlock() const { return DefIterator.getPhiArgBlock(); }
1205 
1206 private:
1207  void fillInCurrentPair() {
1208  CurrentPair.first = *DefIterator;
1209  if (WalkingPhi && Location.Ptr) {
1210  PHITransAddr Translator(
1211  const_cast<Value *>(Location.Ptr),
1212  OriginalAccess->getBlock()->getModule()->getDataLayout(), nullptr);
1213  if (!Translator.PHITranslateValue(OriginalAccess->getBlock(),
1214  DefIterator.getPhiArgBlock(), nullptr,
1215  false))
1216  if (Translator.getAddr() != Location.Ptr) {
1217  CurrentPair.second = Location.getWithNewPtr(Translator.getAddr());
1218  return;
1219  }
1220  }
1221  CurrentPair.second = Location;
1222  }
1223 
1224  MemoryAccessPair CurrentPair;
1225  memoryaccess_def_iterator DefIterator;
1226  MemoryLocation Location;
1227  MemoryAccess *OriginalAccess = nullptr;
1228  bool WalkingPhi = false;
1229 };
1230 
1232  return upward_defs_iterator(Pair);
1233 }
1234 
1236 
1239  return make_range(upward_defs_begin(Pair), upward_defs_end());
1240 }
1241 
1242 /// Walks the defining accesses of MemoryDefs. Stops after we hit something that
1243 /// has no defining use (e.g. a MemoryPhi or liveOnEntry). Note that, when
1244 /// comparing against a null def_chain_iterator, this will compare equal only
1245 /// after walking said Phi/liveOnEntry.
1246 ///
1247 /// The UseOptimizedChain flag specifies whether to walk the clobbering
1248 /// access chain, or all the accesses.
1249 ///
1250 /// Normally, MemoryDef are all just def/use linked together, so a def_chain on
1251 /// a MemoryDef will walk all MemoryDefs above it in the program until it hits
1252 /// a phi node. The optimized chain walks the clobbering access of a store.
1253 /// So if you are just trying to find, given a store, what the next
1254 /// thing that would clobber the same memory is, you want the optimized chain.
1255 template <class T, bool UseOptimizedChain = false>
1257  : public iterator_facade_base<def_chain_iterator<T, UseOptimizedChain>,
1258  std::forward_iterator_tag, MemoryAccess *> {
1259  def_chain_iterator() : MA(nullptr) {}
1260  def_chain_iterator(T MA) : MA(MA) {}
1261 
1262  T operator*() const { return MA; }
1263 
1265  // N.B. liveOnEntry has a null defining access.
1266  if (auto *MUD = dyn_cast<MemoryUseOrDef>(MA)) {
1267  if (UseOptimizedChain && MUD->isOptimized())
1268  MA = MUD->getOptimized();
1269  else
1270  MA = MUD->getDefiningAccess();
1271  } else {
1272  MA = nullptr;
1273  }
1274 
1275  return *this;
1276  }
1277 
1278  bool operator==(const def_chain_iterator &O) const { return MA == O.MA; }
1279 
1280 private:
1281  T MA;
1282 };
1283 
1284 template <class T>
1286 def_chain(T MA, MemoryAccess *UpTo = nullptr) {
1287 #ifdef EXPENSIVE_CHECKS
1288  assert((!UpTo || find(def_chain(MA), UpTo) != def_chain_iterator<T>()) &&
1289  "UpTo isn't in the def chain!");
1290 #endif
1292 }
1293 
1294 template <class T>
1297  def_chain_iterator<T, true>(nullptr));
1298 }
1299 
1300 } // end namespace llvm
1301 
1302 #endif // LLVM_ANALYSIS_MEMORYSSA_H
uint64_t CallInst * C
AccessList * getWritableBlockAccesses(const BasicBlock *BB) const
Definition: MemorySSA.h:797
memoryaccess_def_iterator & operator++()
Definition: MemorySSA.h:1104
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:464
virtual void verify(const MemorySSA *MSSA)
Definition: MemorySSA.h:1041
void unorderedDeleteIncomingValue(const MemoryAccess *MA)
Definition: MemorySSA.h:621
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
void unorderedDeleteIncomingIf(Fn &&Pred)
Definition: MemorySSA.h:602
Result(std::unique_ptr< MemorySSA > &&MSSA)
Definition: MemorySSA.h:924
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:176
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:255
MemorySSAPrinterPass(raw_ostream &OS)
Definition: MemorySSA.h:939
A Module instance is used to store all the information related to an LLVM module. ...
Definition: Module.h:64
void resetOptimized()
Definition: MemorySSA.h:347
const MemorySSA & getMSSA() const
Definition: MemorySSA.h:959
const AccessList * getBlockAccesses(const BasicBlock *BB) const
Return the list of MemoryAccess&#39;s for a given basic block.
Definition: MemorySSA.h:749
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:397
Extension point for the Value hierarchy.
Definition: DerivedUser.h:28
Represents a read-write access to memory, whether it is a must-alias, or a may-alias.
Definition: MemorySSA.h:373
BaseT::iterator::reference operator*() const
Definition: MemorySSA.h:1188
void setOptimized(MemoryAccess *)
Definition: MemorySSA.h:681
void deleteValue()
Delete a pointer to a generic Value.
Definition: Value.cpp:99
BasicBlock * getPhiArgBlock() const
Definition: MemorySSA.h:1088
memoryaccess_def_iterator defs_begin()
This iterator walks over all of the defs in a given MemoryAccess.
Definition: MemorySSA.h:1122
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:30
This defines the Use class.
AllAccessType::const_self_iterator getIterator() const
Definition: MemorySSA.h:179
DefsOnlyType::self_iterator getDefsIterator()
Definition: MemorySSA.h:188
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:344
MemoryPhi * getMemoryAccess(const BasicBlock *BB) const
Definition: MemorySSA.h:715
Represents read-only accesses to memory.
Definition: MemorySSA.h:317
This class is a batch walker of all MemoryUse&#39;s in the program, and points their defining access at t...
Definition: MemorySSA.cpp:1135
Legacy analysis pass which computes MemorySSA.
Definition: MemorySSA.h:950
Definition: BitVector.h:938
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:816
block_iterator block_begin()
Definition: MemorySSA.h:497
A MemorySSAWalker that does AA walks to disambiguate accesses.
Definition: MemorySSA.cpp:942
A Use represents the edge between a Value definition and its users.
Definition: Use.h:56
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:757
const_block_iterator block_end() const
Definition: MemorySSA.h:510
bool isOptimized() const
Definition: MemorySSA.h:401
Walks the defining accesses of MemoryDefs.
Definition: MemorySSA.h:1256
def_chain_iterator & operator++()
Definition: MemorySSA.h:1264
bool isOptimized() const
Definition: MemorySSA.h:669
BaseT::iterator::pointer operator*() const
Definition: MemorySSA.h:1094
static bool classof(const Value *MA)
Definition: MemorySSA.h:388
iterator_range< block_iterator > blocks()
Definition: MemorySSA.h:514
A simple intrusive list implementation.
Definition: simple_ilist.h:79
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:41
static ChildIteratorType child_end(NodeRef N)
Definition: MemorySSA.h:1155
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:711
MemoryAccess * getOptimized() const
Definition: MemorySSA.h:343
AllAccessType::const_reverse_self_iterator getReverseIterator() const
Definition: MemorySSA.h:185
upward_defs_iterator upward_defs_end()
Definition: MemorySSA.h:1235
std::unique_ptr< MemorySSA > MSSA
Definition: MemorySSA.h:928
void unorderedDeleteIncoming(unsigned I)
Definition: MemorySSA.h:586
A CRTP mix-in to automatically provide informational APIs needed for passes.
Definition: PassManager.h:366
This is the generic walker interface for walkers of MemorySSA.
Definition: MemorySSA.h:981
CRTP base class which implements the entire standard iterator facade in terms of a minimal subset of ...
Definition: iterator.h:68
Concrete subclass of DominatorTreeBase that is used to compute a normal dominator tree...
Definition: Dominators.h:145
op_range incoming_values()
Definition: MemorySSA.h:522
memoryaccess_def_iterator defs_end()
Definition: MemorySSA.h:1130
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:94
Use delete by default for iplist and ilist.
Definition: ilist.h:41
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:154
DefsOnlyType::const_reverse_self_iterator getReverseDefsIterator() const
Definition: MemorySSA.h:197
AllAccessType::reverse_self_iterator getReverseIterator()
Definition: MemorySSA.h:182
LLVM Basic Block Representation.
Definition: BasicBlock.h:59
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:36
The instances of the Type class are immutable: once they are created, they are never changed...
Definition: Type.h:46
This is an important class for using LLVM in a threaded context.
Definition: LLVMContext.h:69
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:1195
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:1333
A CRTP mix-in that provides informational APIs needed for analysis passes.
Definition: PassManager.h:383
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:1173
InsertionPlace
Used in various insertion functions to specify whether we are talking about the beginning or end of a...
Definition: MemorySSA.h:782
Represent the analysis usage information of a pass.
iterator_range< def_chain_iterator< T, true > > optimized_def_chain(T MA)
Definition: MemorySSA.h:1295
void print(raw_ostream &OS) const
Definition: MemorySSA.cpp:1984
Printer pass for MemorySSA.
Definition: MemorySSA.h:935
static unsigned getOperandNumForIncomingValue(unsigned I)
Definition: MemorySSA.h:536
FunctionPass class - This class is used to implement most global optimizations.
Definition: Pass.h:285
static bool classof(const Value *MA)
Definition: MemorySSA.h:328
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:1204
virtual void invalidateInfo(MemoryAccess *)
Given a memory access, invalidate anything this walker knows about that access.
Definition: MemorySSA.h:1039
Iterator base class used to implement const and non-const iterators over the defining accesses of a M...
Definition: MemorySSA.h:128
#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:1166
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:1063
An intrusive list with ownership and callbacks specified/controlled by ilist_traits, only with API safe for polymorphic types.
Definition: ilist.h:390
MemoryAccess * getOptimized() const
Definition: MemorySSA.h:675
A MemorySSAWalker that does no alias queries, or anything else.
Definition: MemorySSA.h:1051
std::pair< const MemoryAccess *, MemoryLocation > ConstMemoryAccessPair
Definition: MemorySSA.h:1063
static void deleteNode(MemoryAccess *MA)
Definition: MemorySSA.h:230
unsigned first
bool operator==(const memoryaccess_def_iterator_base &Other) const
Definition: MemorySSA.h:1078
bool isOptimized() const
Definition: MemorySSA.h:339
The two locations may or may not alias. This is the least precise result.
Definition: AliasAnalysis.h:87
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:297
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:418
This is a &#39;vector&#39; (really, a variable-sized array), optimized for the case when the array is small...
Definition: SmallVector.h:847
Module.h This file contains the declarations for the Module class.
An analysis that produces MemorySSA for a function.
Definition: MemorySSA.h:914
BasicBlock * getBlock() const
Definition: MemorySSA.h:157
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:282
MemoryAccess * getLiveOnEntryDef() const
Definition: MemorySSA.h:733
Verifier pass for MemorySSA.
Definition: MemorySSA.h:945
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:245
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:252
iterator_range< const_block_iterator > blocks() const
Definition: MemorySSA.h:518
user_iterator_impl< const User > const_user_iterator
Definition: Value.h:370
DefsOnlyType::const_self_iterator getDefsIterator() const
Definition: MemorySSA.h:191
void setOptimizedAccessType(Optional< AliasResult > AR)
Definition: MemorySSA.h:293
iterator_range< def_chain_iterator< T > > def_chain(T MA, MemoryAccess *UpTo=nullptr)
Definition: MemorySSA.h:1286
memoryaccess_def_iterator_base< MemoryAccess > memoryaccess_def_iterator
Definition: MemorySSA.h:129
block_iterator block_end()
Definition: MemorySSA.h:508
bool operator==(const def_chain_iterator &O) const
Definition: MemorySSA.h:1278
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:369
MemoryAccess * getIncomingValueForBlock(const BasicBlock *BB) const
Definition: MemorySSA.h:579
Compile-time customization of User operands.
Definition: User.h:43
MemoryAccess(LLVMContext &C, unsigned Vty, DeleteValueTy DeleteValue, BasicBlock *BB, unsigned NumOperands)
Definition: MemorySSA.h:216
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:323
bool isLiveOnEntryDef(const MemoryAccess *MA) const
Return true if MA represents the live on entry value.
Definition: MemorySSA.h:729
Optional< AliasResult > getOptimizedAccessType() const
Definition: MemorySSA.h:269
raw_ostream & operator<<(raw_ostream &OS, const APInt &I)
Definition: APInt.h:2033
static ChildIteratorType child_begin(NodeRef N)
Definition: MemorySSA.h:1154
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:1010
static ChildIteratorType child_begin(NodeRef N)
Definition: MemorySSA.h:1145
static bool classof(const Value *MA)
Definition: MemorySSA.h:257
assert(ImpDefSCC.getReg()==AMDGPU::SCC &&ImpDefSCC.isDef())
user_iterator user_begin()
Definition: Value.h:376
void setOptimized(MemoryAccess *MA)
Definition: MemorySSA.h:392
static NodeRef getEntryNode(NodeRef N)
Definition: MemorySSA.h:1144
LLVM Value Representation.
Definition: Value.h:73
MemoryDef(LLVMContext &C, MemoryAccess *DMA, Instruction *MI, BasicBlock *BB, unsigned Ver)
Definition: MemorySSA.h:379
DefsOnlyType::reverse_self_iterator getReverseDefsIterator()
Definition: MemorySSA.h:194
upward_defs_iterator upward_defs_begin(const MemoryAccessPair &Pair)
Definition: MemorySSA.h:1231
HungoffOperandTraits - determine the allocation regime of the Use array when it is not a prefix to th...
Definition: OperandTraits.h:96
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:40
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:46
const_user_iterator const_iterator
Definition: MemorySSA.h:164
IRTranslator LLVM IR MI
FixedNumOperandTraits - determine the allocation regime of the Use array when it is a prefix to the U...
Definition: OperandTraits.h:31
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:210
MemoryUse(LLVMContext &C, MemoryAccess *DMA, Instruction *MI, BasicBlock *BB)
Definition: MemorySSA.h:321
static bool classof(const Value *V)
Definition: MemorySSA.h:152
iterator_range< upward_defs_iterator > upward_defs(const MemoryAccessPair &Pair)
Definition: MemorySSA.h:1238
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:1146
DefsList * getWritableBlockDefs(const BasicBlock *BB) const
Definition: MemorySSA.h:803
user_iterator iterator
The user iterators for a memory access.
Definition: MemorySSA.h:163
memoryaccess_def_iterator_base< const MemoryAccess > const_memoryaccess_def_iterator
Definition: MemorySSA.h:131
bool operator==(const upward_defs_iterator &Other) const
Definition: MemorySSA.h:1184
A special type used by analysis passes to provide an address that identifies that particular analysis...
Definition: PassManager.h:71
void resetOptimized()
Definition: MemorySSA.h:405
void setOptimized(MemoryAccess *DMA)
Definition: MemorySSA.h:334
std::pair< MemoryAccess *, MemoryLocation > MemoryAccessPair
Definition: MemorySSA.h:1062
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:384