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Diffstat (limited to 'contrib/llvm/lib/Analysis/PointerTracking.cpp')
| -rw-r--r-- | contrib/llvm/lib/Analysis/PointerTracking.cpp | 316 |
1 files changed, 0 insertions, 316 deletions
diff --git a/contrib/llvm/lib/Analysis/PointerTracking.cpp b/contrib/llvm/lib/Analysis/PointerTracking.cpp deleted file mode 100644 index 07f4682..0000000 --- a/contrib/llvm/lib/Analysis/PointerTracking.cpp +++ /dev/null @@ -1,316 +0,0 @@ -//===- PointerTracking.cpp - Pointer Bounds Tracking ------------*- C++ -*-===// -// -// The LLVM Compiler Infrastructure -// -// This file is distributed under the University of Illinois Open Source -// License. See LICENSE.TXT for details. -// -//===----------------------------------------------------------------------===// -// -// This file implements tracking of pointer bounds. -// -//===----------------------------------------------------------------------===// - -#include "llvm/Analysis/ConstantFolding.h" -#include "llvm/Analysis/Dominators.h" -#include "llvm/Analysis/LoopInfo.h" -#include "llvm/Analysis/MemoryBuiltins.h" -#include "llvm/Analysis/PointerTracking.h" -#include "llvm/Analysis/ScalarEvolution.h" -#include "llvm/Analysis/ScalarEvolutionExpressions.h" -#include "llvm/Constants.h" -#include "llvm/Module.h" -#include "llvm/Value.h" -#include "llvm/Support/CallSite.h" -#include "llvm/Support/InstIterator.h" -#include "llvm/Support/raw_ostream.h" -#include "llvm/Target/TargetData.h" -using namespace llvm; - -char PointerTracking::ID = 0; -PointerTracking::PointerTracking() : FunctionPass(ID) {} - -bool PointerTracking::runOnFunction(Function &F) { - predCache.clear(); - assert(analyzing.empty()); - FF = &F; - TD = getAnalysisIfAvailable<TargetData>(); - SE = &getAnalysis<ScalarEvolution>(); - LI = &getAnalysis<LoopInfo>(); - DT = &getAnalysis<DominatorTree>(); - return false; -} - -void PointerTracking::getAnalysisUsage(AnalysisUsage &AU) const { - AU.addRequiredTransitive<DominatorTree>(); - AU.addRequiredTransitive<LoopInfo>(); - AU.addRequiredTransitive<ScalarEvolution>(); - AU.setPreservesAll(); -} - -bool PointerTracking::doInitialization(Module &M) { - const Type *PTy = Type::getInt8PtrTy(M.getContext()); - - // Find calloc(i64, i64) or calloc(i32, i32). - callocFunc = M.getFunction("calloc"); - if (callocFunc) { - const FunctionType *Ty = callocFunc->getFunctionType(); - - std::vector<const Type*> args, args2; - args.push_back(Type::getInt64Ty(M.getContext())); - args.push_back(Type::getInt64Ty(M.getContext())); - args2.push_back(Type::getInt32Ty(M.getContext())); - args2.push_back(Type::getInt32Ty(M.getContext())); - const FunctionType *Calloc1Type = - FunctionType::get(PTy, args, false); - const FunctionType *Calloc2Type = - FunctionType::get(PTy, args2, false); - if (Ty != Calloc1Type && Ty != Calloc2Type) - callocFunc = 0; // Give up - } - - // Find realloc(i8*, i64) or realloc(i8*, i32). - reallocFunc = M.getFunction("realloc"); - if (reallocFunc) { - const FunctionType *Ty = reallocFunc->getFunctionType(); - std::vector<const Type*> args, args2; - args.push_back(PTy); - args.push_back(Type::getInt64Ty(M.getContext())); - args2.push_back(PTy); - args2.push_back(Type::getInt32Ty(M.getContext())); - - const FunctionType *Realloc1Type = - FunctionType::get(PTy, args, false); - const FunctionType *Realloc2Type = - FunctionType::get(PTy, args2, false); - if (Ty != Realloc1Type && Ty != Realloc2Type) - reallocFunc = 0; // Give up - } - return false; -} - -// Calculates the number of elements allocated for pointer P, -// the type of the element is stored in Ty. -const SCEV *PointerTracking::computeAllocationCount(Value *P, - const Type *&Ty) const { - Value *V = P->stripPointerCasts(); - if (AllocaInst *AI = dyn_cast<AllocaInst>(V)) { - Value *arraySize = AI->getArraySize(); - Ty = AI->getAllocatedType(); - // arraySize elements of type Ty. - return SE->getSCEV(arraySize); - } - - if (CallInst *CI = extractMallocCall(V)) { - Value *arraySize = getMallocArraySize(CI, TD); - const Type* AllocTy = getMallocAllocatedType(CI); - if (!AllocTy || !arraySize) return SE->getCouldNotCompute(); - Ty = AllocTy; - // arraySize elements of type Ty. - return SE->getSCEV(arraySize); - } - - if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) { - if (GV->hasDefinitiveInitializer()) { - Constant *C = GV->getInitializer(); - if (const ArrayType *ATy = dyn_cast<ArrayType>(C->getType())) { - Ty = ATy->getElementType(); - return SE->getConstant(Type::getInt32Ty(P->getContext()), - ATy->getNumElements()); - } - } - Ty = GV->getType(); - return SE->getConstant(Type::getInt32Ty(P->getContext()), 1); - //TODO: implement more tracking for globals - } - - if (CallInst *CI = dyn_cast<CallInst>(V)) { - CallSite CS(CI); - Function *F = dyn_cast<Function>(CS.getCalledValue()->stripPointerCasts()); - const Loop *L = LI->getLoopFor(CI->getParent()); - if (F == callocFunc) { - Ty = Type::getInt8Ty(P->getContext()); - // calloc allocates arg0*arg1 bytes. - return SE->getSCEVAtScope(SE->getMulExpr(SE->getSCEV(CS.getArgument(0)), - SE->getSCEV(CS.getArgument(1))), - L); - } else if (F == reallocFunc) { - Ty = Type::getInt8Ty(P->getContext()); - // realloc allocates arg1 bytes. - return SE->getSCEVAtScope(CS.getArgument(1), L); - } - } - - return SE->getCouldNotCompute(); -} - -Value *PointerTracking::computeAllocationCountValue(Value *P, const Type *&Ty) const -{ - Value *V = P->stripPointerCasts(); - if (AllocaInst *AI = dyn_cast<AllocaInst>(V)) { - Ty = AI->getAllocatedType(); - // arraySize elements of type Ty. - return AI->getArraySize(); - } - - if (CallInst *CI = extractMallocCall(V)) { - Ty = getMallocAllocatedType(CI); - if (!Ty) - return 0; - Value *arraySize = getMallocArraySize(CI, TD); - if (!arraySize) { - Ty = Type::getInt8Ty(P->getContext()); - return CI->getArgOperand(0); - } - // arraySize elements of type Ty. - return arraySize; - } - - if (GlobalVariable *GV = dyn_cast<GlobalVariable>(V)) { - if (GV->hasDefinitiveInitializer()) { - Constant *C = GV->getInitializer(); - if (const ArrayType *ATy = dyn_cast<ArrayType>(C->getType())) { - Ty = ATy->getElementType(); - return ConstantInt::get(Type::getInt32Ty(P->getContext()), - ATy->getNumElements()); - } - } - Ty = cast<PointerType>(GV->getType())->getElementType(); - return ConstantInt::get(Type::getInt32Ty(P->getContext()), 1); - //TODO: implement more tracking for globals - } - - if (CallInst *CI = dyn_cast<CallInst>(V)) { - CallSite CS(CI); - Function *F = dyn_cast<Function>(CS.getCalledValue()->stripPointerCasts()); - if (F == reallocFunc) { - Ty = Type::getInt8Ty(P->getContext()); - // realloc allocates arg1 bytes. - return CS.getArgument(1); - } - } - - return 0; -} - -// Calculates the number of elements of type Ty allocated for P. -const SCEV *PointerTracking::computeAllocationCountForType(Value *P, - const Type *Ty) - const { - const Type *elementTy; - const SCEV *Count = computeAllocationCount(P, elementTy); - if (isa<SCEVCouldNotCompute>(Count)) - return Count; - if (elementTy == Ty) - return Count; - - if (!TD) // need TargetData from this point forward - return SE->getCouldNotCompute(); - - uint64_t elementSize = TD->getTypeAllocSize(elementTy); - uint64_t wantSize = TD->getTypeAllocSize(Ty); - if (elementSize == wantSize) - return Count; - if (elementSize % wantSize) //fractional counts not possible - return SE->getCouldNotCompute(); - return SE->getMulExpr(Count, SE->getConstant(Count->getType(), - elementSize/wantSize)); -} - -const SCEV *PointerTracking::getAllocationElementCount(Value *V) const { - // We only deal with pointers. - const PointerType *PTy = cast<PointerType>(V->getType()); - return computeAllocationCountForType(V, PTy->getElementType()); -} - -const SCEV *PointerTracking::getAllocationSizeInBytes(Value *V) const { - return computeAllocationCountForType(V, Type::getInt8Ty(V->getContext())); -} - -// Helper for isLoopGuardedBy that checks the swapped and inverted predicate too -enum SolverResult PointerTracking::isLoopGuardedBy(const Loop *L, - Predicate Pred, - const SCEV *A, - const SCEV *B) const { - if (SE->isLoopEntryGuardedByCond(L, Pred, A, B)) - return AlwaysTrue; - Pred = ICmpInst::getSwappedPredicate(Pred); - if (SE->isLoopEntryGuardedByCond(L, Pred, B, A)) - return AlwaysTrue; - - Pred = ICmpInst::getInversePredicate(Pred); - if (SE->isLoopEntryGuardedByCond(L, Pred, B, A)) - return AlwaysFalse; - Pred = ICmpInst::getSwappedPredicate(Pred); - if (SE->isLoopEntryGuardedByCond(L, Pred, A, B)) - return AlwaysTrue; - return Unknown; -} - -enum SolverResult PointerTracking::checkLimits(const SCEV *Offset, - const SCEV *Limit, - BasicBlock *BB) -{ - //FIXME: merge implementation - return Unknown; -} - -void PointerTracking::getPointerOffset(Value *Pointer, Value *&Base, - const SCEV *&Limit, - const SCEV *&Offset) const -{ - Pointer = Pointer->stripPointerCasts(); - Base = Pointer->getUnderlyingObject(); - Limit = getAllocationSizeInBytes(Base); - if (isa<SCEVCouldNotCompute>(Limit)) { - Base = 0; - Offset = Limit; - return; - } - - Offset = SE->getMinusSCEV(SE->getSCEV(Pointer), SE->getSCEV(Base)); - if (isa<SCEVCouldNotCompute>(Offset)) { - Base = 0; - Limit = Offset; - } -} - -void PointerTracking::print(raw_ostream &OS, const Module* M) const { - // Calling some PT methods may cause caches to be updated, however - // this should be safe for the same reason its safe for SCEV. - PointerTracking &PT = *const_cast<PointerTracking*>(this); - for (inst_iterator I=inst_begin(*FF), E=inst_end(*FF); I != E; ++I) { - if (!I->getType()->isPointerTy()) - continue; - Value *Base; - const SCEV *Limit, *Offset; - getPointerOffset(&*I, Base, Limit, Offset); - if (!Base) - continue; - - if (Base == &*I) { - const SCEV *S = getAllocationElementCount(Base); - OS << *Base << " ==> " << *S << " elements, "; - OS << *Limit << " bytes allocated\n"; - continue; - } - OS << &*I << " -- base: " << *Base; - OS << " offset: " << *Offset; - - enum SolverResult res = PT.checkLimits(Offset, Limit, I->getParent()); - switch (res) { - case AlwaysTrue: - OS << " always safe\n"; - break; - case AlwaysFalse: - OS << " always unsafe\n"; - break; - case Unknown: - OS << " <<unknown>>\n"; - break; - } - } -} - -INITIALIZE_PASS(PointerTracking, "pointertracking", - "Track pointer bounds", false, true); |
