//===- AliasAnalysis.cpp - Generic Alias Analysis Interface Implementation -==//
-//
+//
// The LLVM Compiler Infrastructure
//
-// This file was developed by the LLVM research group and is distributed under
-// the University of Illinois Open Source License. See LICENSE.TXT for details.
-//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
//===----------------------------------------------------------------------===//
//
// This file implements the generic AliasAnalysis interface which is used as the
//===----------------------------------------------------------------------===//
#include "llvm/Analysis/AliasAnalysis.h"
+#include "llvm/Pass.h"
#include "llvm/BasicBlock.h"
-#include "llvm/iMemory.h"
+#include "llvm/Function.h"
+#include "llvm/Instructions.h"
+#include "llvm/Type.h"
#include "llvm/Target/TargetData.h"
+using namespace llvm;
// Register the AliasAnalysis interface, providing a nice name to refer to.
namespace {
RegisterAnalysisGroup<AliasAnalysis> Z("Alias Analysis");
}
+char AliasAnalysis::ID = 0;
+
+//===----------------------------------------------------------------------===//
+// Default chaining methods
+//===----------------------------------------------------------------------===//
+
+AliasAnalysis::AliasResult
+AliasAnalysis::alias(const Value *V1, unsigned V1Size,
+ const Value *V2, unsigned V2Size) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+ return AA->alias(V1, V1Size, V2, V2Size);
+}
+
+void AliasAnalysis::getMustAliases(Value *P, std::vector<Value*> &RetVals) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+ return AA->getMustAliases(P, RetVals);
+}
+
+bool AliasAnalysis::pointsToConstantMemory(const Value *P) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+ return AA->pointsToConstantMemory(P);
+}
+
+AliasAnalysis::ModRefBehavior
+AliasAnalysis::getModRefBehavior(Function *F, CallSite CS,
+ std::vector<PointerAccessInfo> *Info) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+ return AA->getModRefBehavior(F, CS, Info);
+}
+
+bool AliasAnalysis::hasNoModRefInfoForCalls() const {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+ return AA->hasNoModRefInfoForCalls();
+}
+
+void AliasAnalysis::deleteValue(Value *V) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+ AA->deleteValue(V);
+}
+
+void AliasAnalysis::copyValue(Value *From, Value *To) {
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+ AA->copyValue(From, To);
+}
+
+AliasAnalysis::ModRefResult
+AliasAnalysis::getModRefInfo(CallSite CS1, CallSite CS2) {
+ // FIXME: we can do better.
+ assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
+ return AA->getModRefInfo(CS1, CS2);
+}
+
+
+//===----------------------------------------------------------------------===//
+// AliasAnalysis non-virtual helper method implementation
+//===----------------------------------------------------------------------===//
AliasAnalysis::ModRefResult
AliasAnalysis::getModRefInfo(LoadInst *L, Value *P, unsigned Size) {
- return alias(L->getOperand(0), TD->getTypeSize(L->getType()),
+ return alias(L->getOperand(0), TD->getTypeStoreSize(L->getType()),
P, Size) ? Ref : NoModRef;
}
AliasAnalysis::ModRefResult
AliasAnalysis::getModRefInfo(StoreInst *S, Value *P, unsigned Size) {
- return alias(S->getOperand(1), TD->getTypeSize(S->getOperand(0)->getType()),
- P, Size) ? Mod : NoModRef;
+ // If the stored address cannot alias the pointer in question, then the
+ // pointer cannot be modified by the store.
+ if (!alias(S->getOperand(1),
+ TD->getTypeStoreSize(S->getOperand(0)->getType()), P, Size))
+ return NoModRef;
+
+ // If the pointer is a pointer to constant memory, then it could not have been
+ // modified by this store.
+ return pointsToConstantMemory(P) ? NoModRef : Mod;
+}
+
+AliasAnalysis::ModRefBehavior
+AliasAnalysis::getModRefBehavior(CallSite CS,
+ std::vector<PointerAccessInfo> *Info) {
+ if (CS.doesNotAccessMemory())
+ // Can't do better than this.
+ return DoesNotAccessMemory;
+ ModRefBehavior MRB = UnknownModRefBehavior;
+ if (Function *F = CS.getCalledFunction())
+ MRB = getModRefBehavior(F, CS, Info);
+ if (MRB != DoesNotAccessMemory && CS.onlyReadsMemory())
+ return OnlyReadsMemory;
+ return MRB;
+}
+
+AliasAnalysis::ModRefBehavior
+AliasAnalysis::getModRefBehavior(Function *F,
+ std::vector<PointerAccessInfo> *Info) {
+ if (F->doesNotAccessMemory())
+ // Can't do better than this.
+ return DoesNotAccessMemory;
+ ModRefBehavior MRB = getModRefBehavior(F, CallSite(), Info);
+ if (MRB != DoesNotAccessMemory && F->onlyReadsMemory())
+ return OnlyReadsMemory;
+ return MRB;
}
+AliasAnalysis::ModRefResult
+AliasAnalysis::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
+ ModRefResult Mask = ModRef;
+ ModRefBehavior MRB = getModRefBehavior(CS);
+ if (MRB == OnlyReadsMemory)
+ Mask = Ref;
+ else if (MRB == DoesNotAccessMemory)
+ return NoModRef;
+
+ if (!AA) return Mask;
+
+ // If P points to a constant memory location, the call definitely could not
+ // modify the memory location.
+ if ((Mask & Mod) && AA->pointsToConstantMemory(P))
+ Mask = ModRefResult(Mask & ~Mod);
+
+ return ModRefResult(Mask & AA->getModRefInfo(CS, P, Size));
+}
// AliasAnalysis destructor: DO NOT move this to the header file for
// AliasAnalysis or else clients of the AliasAnalysis class may not depend on
///
void AliasAnalysis::InitializeAliasAnalysis(Pass *P) {
TD = &P->getAnalysis<TargetData>();
+ AA = &P->getAnalysis<AliasAnalysis>();
}
// getAnalysisUsage - All alias analysis implementations should invoke this
// TargetData is required by the pass.
void AliasAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<TargetData>(); // All AA's need TargetData.
+ AU.addRequired<AliasAnalysis>(); // All AA's chain
}
/// canBasicBlockModify - Return true if it is possible for execution of the
// be pulled in if the AliasAnalysis classes are pulled in. Otherwise we run
// the risk of AliasAnalysis being used, but the default implementation not
// being linked into the tool that uses it.
-//
-extern void BasicAAStub();
-static IncludeFile INCLUDE_BASICAA_CPP((void*)&BasicAAStub);
-
-
-namespace {
- struct NoAA : public ImmutablePass, public AliasAnalysis {
- virtual void getAnalysisUsage(AnalysisUsage &AU) const {
- AliasAnalysis::getAnalysisUsage(AU);
- }
-
- virtual void initializePass() {
- InitializeAliasAnalysis(this);
- }
- };
-
- // Register this pass...
- RegisterOpt<NoAA>
- X("no-aa", "No Alias Analysis (always returns 'may' alias)");
-
- // Declare that we implement the AliasAnalysis interface
- RegisterAnalysisGroup<AliasAnalysis, NoAA> Y;
-} // End of anonymous namespace
+DEFINING_FILE_FOR(AliasAnalysis)
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