Merge "Update prebuilt Clang to r353983." into p9.0HEADp9.0-backupp9.0

1 files changed, 278 insertions, 0 deletions

diff --git a/clang-r353983/include/llvm/Analysis/BasicAliasAnalysis.h b/clang-r353983/include/llvm/Analysis/BasicAliasAnalysis.h
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+//===- BasicAliasAnalysis.h - Stateless, local Alias Analysis ---*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+/// \file
+/// This is the interface for LLVM's primary stateless and local alias analysis.
+///
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_ANALYSIS_BASICALIASANALYSIS_H
+#define LLVM_ANALYSIS_BASICALIASANALYSIS_H
+
+#include "llvm/ADT/DenseMap.h"
+#include "llvm/ADT/Optional.h"
+#include "llvm/ADT/SmallPtrSet.h"
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Analysis/AssumptionCache.h"
+#include "llvm/Analysis/MemoryLocation.h"
+#include "llvm/IR/InstrTypes.h"
+#include "llvm/IR/PassManager.h"
+#include "llvm/Pass.h"
+#include <algorithm>
+#include <cstdint>
+#include <memory>
+#include <utility>
+
+namespace llvm {
+
+struct AAMDNodes;
+class APInt;
+class AssumptionCache;
+class BasicBlock;
+class DataLayout;
+class DominatorTree;
+class Function;
+class GEPOperator;
+class LoopInfo;
+class PHINode;
+class SelectInst;
+class TargetLibraryInfo;
+class PhiValues;
+class Value;
+
+/// This is the AA result object for the basic, local, and stateless alias
+/// analysis. It implements the AA query interface in an entirely stateless
+/// manner. As one consequence, it is never invalidated due to IR changes.
+/// While it does retain some storage, that is used as an optimization and not
+/// to preserve information from query to query. However it does retain handles
+/// to various other analyses and must be recomputed when those analyses are.
+class BasicAAResult : public AAResultBase<BasicAAResult> {
+  friend AAResultBase<BasicAAResult>;
+
+  const DataLayout &DL;
+  const Function &F;
+  const TargetLibraryInfo &TLI;
+  AssumptionCache &AC;
+  DominatorTree *DT;
+  LoopInfo *LI;
+  PhiValues *PV;
+
+public:
+  BasicAAResult(const DataLayout &DL, const Function &F,
+                const TargetLibraryInfo &TLI, AssumptionCache &AC,
+                DominatorTree *DT = nullptr, LoopInfo *LI = nullptr,
+                PhiValues *PV = nullptr)
+      : AAResultBase(), DL(DL), F(F), TLI(TLI), AC(AC), DT(DT), LI(LI), PV(PV)
+        {}
+
+  BasicAAResult(const BasicAAResult &Arg)
+      : AAResultBase(Arg), DL(Arg.DL), F(Arg.F), TLI(Arg.TLI), AC(Arg.AC),
+        DT(Arg.DT),  LI(Arg.LI), PV(Arg.PV) {}
+  BasicAAResult(BasicAAResult &&Arg)
+      : AAResultBase(std::move(Arg)), DL(Arg.DL), F(Arg.F), TLI(Arg.TLI),
+        AC(Arg.AC), DT(Arg.DT), LI(Arg.LI), PV(Arg.PV) {}
+
+  /// Handle invalidation events in the new pass manager.
+  bool invalidate(Function &Fn, const PreservedAnalyses &PA,
+                  FunctionAnalysisManager::Invalidator &Inv);
+
+  AliasResult alias(const MemoryLocation &LocA, const MemoryLocation &LocB);
+
+  ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc);
+
+  ModRefInfo getModRefInfo(const CallBase *Call1, const CallBase *Call2);
+
+  /// Chases pointers until we find a (constant global) or not.
+  bool pointsToConstantMemory(const MemoryLocation &Loc, bool OrLocal);
+
+  /// Get the location associated with a pointer argument of a callsite.
+  ModRefInfo getArgModRefInfo(const CallBase *Call, unsigned ArgIdx);
+
+  /// Returns the behavior when calling the given call site.
+  FunctionModRefBehavior getModRefBehavior(const CallBase *Call);
+
+  /// Returns the behavior when calling the given function. For use when the
+  /// call site is not known.
+  FunctionModRefBehavior getModRefBehavior(const Function *Fn);
+
+private:
+  // A linear transformation of a Value; this class represents ZExt(SExt(V,
+  // SExtBits), ZExtBits) * Scale + Offset.
+  struct VariableGEPIndex {
+    // An opaque Value - we can't decompose this further.
+    const Value *V;
+
+    // We need to track what extensions we've done as we consider the same Value
+    // with different extensions as different variables in a GEP's linear
+    // expression;
+    // e.g.: if V == -1, then sext(x) != zext(x).
+    unsigned ZExtBits;
+    unsigned SExtBits;
+
+    APInt Scale;
+
+    bool operator==(const VariableGEPIndex &Other) const {
+      return V == Other.V && ZExtBits == Other.ZExtBits &&
+             SExtBits == Other.SExtBits && Scale == Other.Scale;
+    }
+
+    bool operator!=(const VariableGEPIndex &Other) const {
+      return !operator==(Other);
+    }
+  };
+
+  // Represents the internal structure of a GEP, decomposed into a base pointer,
+  // constant offsets, and variable scaled indices.
+  struct DecomposedGEP {
+    // Base pointer of the GEP
+    const Value *Base;
+    // Total constant offset w.r.t the base from indexing into structs
+    APInt StructOffset;
+    // Total constant offset w.r.t the base from indexing through
+    // pointers/arrays/vectors
+    APInt OtherOffset;
+    // Scaled variable (non-constant) indices.
+    SmallVector<VariableGEPIndex, 4> VarIndices;
+  };
+
+  /// Track alias queries to guard against recursion.
+  using LocPair = std::pair<MemoryLocation, MemoryLocation>;
+  using AliasCacheTy = SmallDenseMap<LocPair, AliasResult, 8>;
+  AliasCacheTy AliasCache;
+  using IsCapturedCacheTy = SmallDenseMap<const Value *, bool, 8>;
+  IsCapturedCacheTy IsCapturedCache;
+
+  /// Tracks phi nodes we have visited.
+  ///
+  /// When interpret "Value" pointer equality as value equality we need to make
+  /// sure that the "Value" is not part of a cycle. Otherwise, two uses could
+  /// come from different "iterations" of a cycle and see different values for
+  /// the same "Value" pointer.
+  ///
+  /// The following example shows the problem:
+  ///   %p = phi(%alloca1, %addr2)
+  ///   %l = load %ptr
+  ///   %addr1 = gep, %alloca2, 0, %l
+  ///   %addr2 = gep  %alloca2, 0, (%l + 1)
+  ///      alias(%p, %addr1) -> MayAlias !
+  ///   store %l, ...
+  SmallPtrSet<const BasicBlock *, 8> VisitedPhiBBs;
+
+  /// Tracks instructions visited by pointsToConstantMemory.
+  SmallPtrSet<const Value *, 16> Visited;
+
+  static const Value *
+  GetLinearExpression(const Value *V, APInt &Scale, APInt &Offset,
+                      unsigned &ZExtBits, unsigned &SExtBits,
+                      const DataLayout &DL, unsigned Depth, AssumptionCache *AC,
+                      DominatorTree *DT, bool &NSW, bool &NUW);
+
+  static bool DecomposeGEPExpression(const Value *V, DecomposedGEP &Decomposed,
+      const DataLayout &DL, AssumptionCache *AC, DominatorTree *DT);
+
+  static bool isGEPBaseAtNegativeOffset(const GEPOperator *GEPOp,
+      const DecomposedGEP &DecompGEP, const DecomposedGEP &DecompObject,
+      LocationSize ObjectAccessSize);
+
+  /// A Heuristic for aliasGEP that searches for a constant offset
+  /// between the variables.
+  ///
+  /// GetLinearExpression has some limitations, as generally zext(%x + 1)
+  /// != zext(%x) + zext(1) if the arithmetic overflows. GetLinearExpression
+  /// will therefore conservatively refuse to decompose these expressions.
+  /// However, we know that, for all %x, zext(%x) != zext(%x + 1), even if
+  /// the addition overflows.
+  bool
+  constantOffsetHeuristic(const SmallVectorImpl<VariableGEPIndex> &VarIndices,
+                          LocationSize V1Size, LocationSize V2Size,
+                          APInt BaseOffset, AssumptionCache *AC,
+                          DominatorTree *DT);
+
+  bool isValueEqualInPotentialCycles(const Value *V1, const Value *V2);
+
+  void GetIndexDifference(SmallVectorImpl<VariableGEPIndex> &Dest,
+                          const SmallVectorImpl<VariableGEPIndex> &Src);
+
+  AliasResult aliasGEP(const GEPOperator *V1, LocationSize V1Size,
+                       const AAMDNodes &V1AAInfo, const Value *V2,
+                       LocationSize V2Size, const AAMDNodes &V2AAInfo,
+                       const Value *UnderlyingV1, const Value *UnderlyingV2);
+
+  AliasResult aliasPHI(const PHINode *PN, LocationSize PNSize,
+                       const AAMDNodes &PNAAInfo, const Value *V2,
+                       LocationSize V2Size, const AAMDNodes &V2AAInfo,
+                       const Value *UnderV2);
+
+  AliasResult aliasSelect(const SelectInst *SI, LocationSize SISize,
+                          const AAMDNodes &SIAAInfo, const Value *V2,
+                          LocationSize V2Size, const AAMDNodes &V2AAInfo,
+                          const Value *UnderV2);
+
+  AliasResult aliasCheck(const Value *V1, LocationSize V1Size,
+                         AAMDNodes V1AATag, const Value *V2,
+                         LocationSize V2Size, AAMDNodes V2AATag,
+                         const Value *O1 = nullptr, const Value *O2 = nullptr);
+};
+
+/// Analysis pass providing a never-invalidated alias analysis result.
+class BasicAA : public AnalysisInfoMixin<BasicAA> {
+  friend AnalysisInfoMixin<BasicAA>;
+
+  static AnalysisKey Key;
+
+public:
+  using Result = BasicAAResult;
+
+  BasicAAResult run(Function &F, FunctionAnalysisManager &AM);
+};
+
+/// Legacy wrapper pass to provide the BasicAAResult object.
+class BasicAAWrapperPass : public FunctionPass {
+  std::unique_ptr<BasicAAResult> Result;
+
+  virtual void anchor();
+
+public:
+  static char ID;
+
+  BasicAAWrapperPass();
+
+  BasicAAResult &getResult() { return *Result; }
+  const BasicAAResult &getResult() const { return *Result; }
+
+  bool runOnFunction(Function &F) override;
+  void getAnalysisUsage(AnalysisUsage &AU) const override;
+};
+
+FunctionPass *createBasicAAWrapperPass();
+
+/// A helper for the legacy pass manager to create a \c BasicAAResult object
+/// populated to the best of our ability for a particular function when inside
+/// of a \c ModulePass or a \c CallGraphSCCPass.
+BasicAAResult createLegacyPMBasicAAResult(Pass &P, Function &F);
+
+/// This class is a functor to be used in legacy module or SCC passes for
+/// computing AA results for a function. We store the results in fields so that
+/// they live long enough to be queried, but we re-use them each time.
+class LegacyAARGetter {
+  Pass &P;
+  Optional<BasicAAResult> BAR;
+  Optional<AAResults> AAR;
+
+public:
+  LegacyAARGetter(Pass &P) : P(P) {}
+  AAResults &operator()(Function &F) {
+    BAR.emplace(createLegacyPMBasicAAResult(P, F));
+    AAR.emplace(createLegacyPMAAResults(P, F, *BAR));
+    return *AAR;
+  }
+};
+
+} // end namespace llvm
+
+#endif // LLVM_ANALYSIS_BASICALIASANALYSIS_H