#include "llvm/Analysis/AliasAnalysis.h"
#include "llvm/Pass.h"
#include "llvm/BasicBlock.h"
#include "llvm/Function.h"
#include "llvm/IntrinsicInst.h"
#include "llvm/Instructions.h"
#include "llvm/Type.h"
#include "llvm/Target/TargetData.h"
using namespace llvm;
static RegisterAnalysisGroup<AliasAnalysis> Z("Alias Analysis");
char AliasAnalysis::ID = 0;
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);
}
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) {
assert(AA && "AA didn't call InitializeAliasAnalysis in its run method!");
return AA->getModRefInfo(CS1, CS2);
}
AliasAnalysis::ModRefResult
AliasAnalysis::getModRefInfo(LoadInst *L, Value *P, unsigned Size) {
return alias(L->getOperand(0), TD->getTypeStoreSize(L->getType()),
P, Size) ? Ref : NoModRef;
}
AliasAnalysis::ModRefResult
AliasAnalysis::getModRefInfo(StoreInst *S, Value *P, unsigned Size) {
if (!alias(S->getOperand(1),
TD->getTypeStoreSize(S->getOperand(0)->getType()), P, Size))
return NoModRef;
return pointsToConstantMemory(P) ? NoModRef : Mod;
}
AliasAnalysis::ModRefBehavior
AliasAnalysis::getModRefBehavior(CallSite CS,
std::vector<PointerAccessInfo> *Info) {
if (CS.doesNotAccessMemory())
return DoesNotAccessMemory;
ModRefBehavior MRB = getModRefBehavior(CS.getCalledFunction(), Info);
if (MRB != DoesNotAccessMemory && CS.onlyReadsMemory())
return OnlyReadsMemory;
return MRB;
}
AliasAnalysis::ModRefBehavior
AliasAnalysis::getModRefBehavior(Function *F,
std::vector<PointerAccessInfo> *Info) {
if (F) {
if (F->doesNotAccessMemory())
return DoesNotAccessMemory;
if (F->onlyReadsMemory())
return OnlyReadsMemory;
if (unsigned id = F->getIntrinsicID()) {
#define GET_INTRINSIC_MODREF_BEHAVIOR
#include "llvm/Intrinsics.gen"
#undef GET_INTRINSIC_MODREF_BEHAVIOR
}
}
return UnknownModRefBehavior;
}
AliasAnalysis::ModRefResult
AliasAnalysis::getModRefInfo(CallSite CS, Value *P, unsigned Size) {
ModRefResult Mask = ModRef;
ModRefBehavior MRB = getModRefBehavior(CS);
if (MRB == DoesNotAccessMemory)
return NoModRef;
else if (MRB == OnlyReadsMemory)
Mask = Ref;
else if (MRB == AliasAnalysis::AccessesArguments) {
bool doesAlias = false;
for (CallSite::arg_iterator AI = CS.arg_begin(), AE = CS.arg_end();
AI != AE; ++AI)
if (alias(*AI, ~0U, P, Size) != NoAlias) {
doesAlias = true;
break;
}
if (!doesAlias)
return NoModRef;
}
if (!AA) return Mask;
if ((Mask & Mod) && AA->pointsToConstantMemory(P))
Mask = ModRefResult(Mask & ~Mod);
return ModRefResult(Mask & AA->getModRefInfo(CS, P, Size));
}
AliasAnalysis::~AliasAnalysis() {}
void AliasAnalysis::InitializeAliasAnalysis(Pass *P) {
TD = &P->getAnalysis<TargetData>();
AA = &P->getAnalysis<AliasAnalysis>();
}
void AliasAnalysis::getAnalysisUsage(AnalysisUsage &AU) const {
AU.addRequired<TargetData>(); AU.addRequired<AliasAnalysis>(); }
bool AliasAnalysis::canBasicBlockModify(const BasicBlock &BB,
const Value *Ptr, unsigned Size) {
return canInstructionRangeModify(BB.front(), BB.back(), Ptr, Size);
}
bool AliasAnalysis::canInstructionRangeModify(const Instruction &I1,
const Instruction &I2,
const Value *Ptr, unsigned Size) {
assert(I1.getParent() == I2.getParent() &&
"Instructions not in same basic block!");
BasicBlock::iterator I = const_cast<Instruction*>(&I1);
BasicBlock::iterator E = const_cast<Instruction*>(&I2);
++E;
for (; I != E; ++I) if (getModRefInfo(I, const_cast<Value*>(Ptr), Size) & Mod)
return true;
return false;
}
bool llvm::isNoAliasCall(const Value *V) {
if (isa<CallInst>(V) || isa<InvokeInst>(V))
return CallSite(const_cast<Instruction*>(cast<Instruction>(V)))
.paramHasAttr(0, Attribute::NoAlias);
return false;
}
bool llvm::isIdentifiedObject(const Value *V) {
if (isa<GlobalValue>(V) || isa<AllocationInst>(V) || isNoAliasCall(V))
return true;
if (const Argument *A = dyn_cast<Argument>(V))
return A->hasNoAliasAttr() || A->hasByValAttr();
return false;
}
DEFINING_FILE_FOR(AliasAnalysis)