linux-x64/clang/include/llvm/Analysis/BasicAliasAnalysis.h - hafnium/prebuilts - Git at Google

 //===- 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,
                     AAQueryInfo &AAQI);

   ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc,
                            AAQueryInfo &AAQI);

   ModRefInfo getModRefInfo(const CallBase *Call1, const CallBase *Call2,
                            AAQueryInfo &AAQI);

   /// Chases pointers until we find a (constant global) or not.
   bool pointsToConstantMemory(const MemoryLocation &Loc, AAQueryInfo &AAQI,
                               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;
   };

   /// 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,
                        AAQueryInfo &AAQI);

   AliasResult aliasPHI(const PHINode *PN, LocationSize PNSize,
                        const AAMDNodes &PNAAInfo, const Value *V2,
                        LocationSize V2Size, const AAMDNodes &V2AAInfo,
                        const Value *UnderV2, AAQueryInfo &AAQI);

   AliasResult aliasSelect(const SelectInst *SI, LocationSize SISize,
                           const AAMDNodes &SIAAInfo, const Value *V2,
                           LocationSize V2Size, const AAMDNodes &V2AAInfo,
                           const Value *UnderV2, AAQueryInfo &AAQI);

   AliasResult aliasCheck(const Value *V1, LocationSize V1Size,
                          AAMDNodes V1AATag, const Value *V2,
                          LocationSize V2Size, AAMDNodes V2AATag,
                          AAQueryInfo &AAQI, 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
	//===- 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,
	AAQueryInfo &AAQI);

	ModRefInfo getModRefInfo(const CallBase *Call, const MemoryLocation &Loc,
	AAQueryInfo &AAQI);

	ModRefInfo getModRefInfo(const CallBase Call1, const CallBase Call2,
	AAQueryInfo &AAQI);

	/// Chases pointers until we find a (constant global) or not.
	bool pointsToConstantMemory(const MemoryLocation &Loc, AAQueryInfo &AAQI,
	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;
	};

	/// 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,
	AAQueryInfo &AAQI);

	AliasResult aliasPHI(const PHINode *PN, LocationSize PNSize,
	const AAMDNodes &PNAAInfo, const Value *V2,
	LocationSize V2Size, const AAMDNodes &V2AAInfo,
	const Value *UnderV2, AAQueryInfo &AAQI);

	AliasResult aliasSelect(const SelectInst *SI, LocationSize SISize,
	const AAMDNodes &SIAAInfo, const Value *V2,
	LocationSize V2Size, const AAMDNodes &V2AAInfo,
	const Value *UnderV2, AAQueryInfo &AAQI);

	AliasResult aliasCheck(const Value *V1, LocationSize V1Size,
	AAMDNodes V1AATag, const Value *V2,
	LocationSize V2Size, AAMDNodes V2AATag,
	AAQueryInfo &AAQI, 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