// // Method: visitGetElementPtrInst() // // Description: // This method checks to see if the specified GEP is safe. If it cannot prove // it safe, it then adds a run-time check for it. // void InsertGEPChecks::visitGetElementPtrInst (GetElementPtrInst & GEP) { // // Don't insert a check if GEP only indexes into a structure and the // user doesn't want to do structure index checking. // if (DisableStructChecks && indexesStructsOnly (&GEP)) { return; } // // Get the function in which the GEP instruction lives. // Value * PH = ConstantPointerNull::get (getVoidPtrType(GEP.getContext())); BasicBlock::iterator InsertPt = &GEP; ++InsertPt; Instruction * ResultPtr = castTo (&GEP, getVoidPtrType(GEP.getContext()), GEP.getName() + ".cast", InsertPt); // // Make this an actual cast instruction; it will make it easier to update // DSA. // Value * SrcPtr = castTo (GEP.getPointerOperand(), getVoidPtrType(GEP.getContext()), GEP.getName()+".cast", InsertPt); // // Create the call to the run-time check. // std::vector<Value *> args(1, PH); args.push_back (SrcPtr); args.push_back (ResultPtr); CallInst * CI = CallInst::Create (PoolCheckArrayUI, args, "", InsertPt); // // Add debugging info metadata to the run-time check. // if (MDNode * MD = GEP.getMetadata ("dbg")) CI->setMetadata ("dbg", MD); // // Update the statistics. // ++GEPChecks; return; }
bool Scalarizer::visitGetElementPtrInst(GetElementPtrInst &GEPI) { VectorType *VT = dyn_cast<VectorType>(GEPI.getType()); if (!VT) return false; IRBuilder<> Builder(&GEPI); unsigned NumElems = VT->getNumElements(); unsigned NumIndices = GEPI.getNumIndices(); Scatterer Base = scatter(&GEPI, GEPI.getOperand(0)); SmallVector<Scatterer, 8> Ops; Ops.resize(NumIndices); for (unsigned I = 0; I < NumIndices; ++I) Ops[I] = scatter(&GEPI, GEPI.getOperand(I + 1)); ValueVector Res; Res.resize(NumElems); for (unsigned I = 0; I < NumElems; ++I) { SmallVector<Value *, 8> Indices; Indices.resize(NumIndices); for (unsigned J = 0; J < NumIndices; ++J) Indices[J] = Ops[J][I]; Res[I] = Builder.CreateGEP(GEPI.getSourceElementType(), Base[I], Indices, GEPI.getName() + ".i" + Twine(I)); if (GEPI.isInBounds()) if (GetElementPtrInst *NewGEPI = dyn_cast<GetElementPtrInst>(Res[I])) NewGEPI->setIsInBounds(); } gather(&GEPI, Res); return true; }
void smtit::performTest1() { for (Module::iterator FI = Mod->begin(), FE = Mod->end(); FI != FE; ++FI) { Function *Func = &*FI; // DEBUG(errs() << *Func << "\n"); for (Function::iterator BI = Func->begin(), BE = Func->end(); BI != BE; ++BI) { BasicBlock *BB = &*BI; for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I) { Instruction *BBI = &*I; //if (true == isa<StoreInst>(BBI)) { if (true == isa<LoadInst>(BBI)) { LoadInst *li = dyn_cast<LoadInst>(BBI); Value *ptrOp = li->getPointerOperand(); DEBUG(errs() << *li << "\t Result Name: " << li->getName() << "\t Pointer Name: " << ptrOp->getName() << "\n"); // DEBUG(errs() << "\tStore Instruction: " << *BBI << " \n"); // DEBUG(errs() << "\t\tPointerType: " << isLLVMPAPtrTy(SI->getType()) // << " \n"); // Instruction* V = cast<Instruction>(SI->getOperand(1)); // DEBUG(errs() << "\tOperand : " << *V << " \n"); // DEBUG(errs() << "\t\tPointerType: " << isLLVMPAPtrTy(V->getType()) // << " \n"); } else if(true == isa<GetElementPtrInst>(BBI)) { GetElementPtrInst *gep = dyn_cast<GetElementPtrInst>(BBI); DEBUG(errs() << *gep << "\t Result Name: " << gep->getName() << "\n"); // DEBUG(errs() << "\tInstruction: " << *BBI << " \n"); // DEBUG(errs() << "\t\tPointerType: " << // isLLVMPAPtrTy(BBI->getType()) << " \n"); } // For def-use chains: All the uses of the definition //DEBUG(errs() << *BBI << "\n"); /* for (User *U : BBI->users()) { if (Instruction *Inst = dyn_cast<Instruction>(U)) { DEBUG(errs()<< " " << *Inst << "\n"); } } for (Value::user_iterator i = BBI->user_begin(), e = BBI->user_end(); i != e; ++i) { if (Instruction *user_inst = dyn_cast<Instruction>(*i)) { DEBUG(errs()<< " " << *user_inst << "\n"); } } */ } } } }
// // Method: runOnModule() // // Description: // Entry point for this LLVM pass. // Find all GEPs, and simplify them. // // Inputs: // M - A reference to the LLVM module to transform // // Outputs: // M - The transformed LLVM module. // // Return value: // true - The module was modified. // false - The module was not modified. // bool SimplifyGEP::runOnModule(Module& M) { TD = &getAnalysis<TargetData>(); preprocess(M); for (Module::iterator F = M.begin(); F != M.end(); ++F){ for (Function::iterator B = F->begin(), FE = F->end(); B != FE; ++B) { for (BasicBlock::iterator I = B->begin(), BE = B->end(); I != BE; I++) { if(!(isa<GetElementPtrInst>(I))) continue; GetElementPtrInst *GEP = cast<GetElementPtrInst>(I); Value *PtrOp = GEP->getOperand(0); Value *StrippedPtr = PtrOp->stripPointerCasts(); // Check if the GEP base pointer is enclosed in a cast if (StrippedPtr != PtrOp) { const PointerType *StrippedPtrTy =cast<PointerType>(StrippedPtr->getType()); bool HasZeroPointerIndex = false; if (ConstantInt *C = dyn_cast<ConstantInt>(GEP->getOperand(1))) HasZeroPointerIndex = C->isZero(); // Transform: GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ... // into : GEP [10 x i8]* X, i32 0, ... // // Likewise, transform: GEP (bitcast i8* X to [0 x i8]*), i32 0, ... // into : GEP i8* X, ... // // This occurs when the program declares an array extern like "int X[];" if (HasZeroPointerIndex) { const PointerType *CPTy = cast<PointerType>(PtrOp->getType()); if (const ArrayType *CATy = dyn_cast<ArrayType>(CPTy->getElementType())) { // GEP (bitcast i8* X to [0 x i8]*), i32 0, ... ? if (CATy->getElementType() == StrippedPtrTy->getElementType()) { // -> GEP i8* X, ... SmallVector<Value*, 8> Idx(GEP->idx_begin()+1, GEP->idx_end()); GetElementPtrInst *Res = GetElementPtrInst::Create(StrippedPtr, Idx, GEP->getName(), GEP); Res->setIsInBounds(GEP->isInBounds()); GEP->replaceAllUsesWith(Res); continue; } if (const ArrayType *XATy = dyn_cast<ArrayType>(StrippedPtrTy->getElementType())){ // GEP (bitcast [10 x i8]* X to [0 x i8]*), i32 0, ... ? if (CATy->getElementType() == XATy->getElementType()) { // -> GEP [10 x i8]* X, i32 0, ... // At this point, we know that the cast source type is a pointer // to an array of the same type as the destination pointer // array. Because the array type is never stepped over (there // is a leading zero) we can fold the cast into this GEP. GEP->setOperand(0, StrippedPtr); continue; } } } } else if (GEP->getNumOperands() == 2) { // Transform things like: // %t = getelementptr i32* bitcast ([2 x i32]* %str to i32*), i32 %V // into: %t1 = getelementptr [2 x i32]* %str, i32 0, i32 %V; bitcast Type *SrcElTy = StrippedPtrTy->getElementType(); Type *ResElTy=cast<PointerType>(PtrOp->getType())->getElementType(); if (TD && SrcElTy->isArrayTy() && TD->getTypeAllocSize(cast<ArrayType>(SrcElTy)->getElementType()) == TD->getTypeAllocSize(ResElTy)) { Value *Idx[2]; Idx[0] = Constant::getNullValue(Type::getInt32Ty(GEP->getContext())); Idx[1] = GEP->getOperand(1); Value *NewGEP = GetElementPtrInst::Create(StrippedPtr, Idx, GEP->getName(), GEP); // V and GEP are both pointer types --> BitCast GEP->replaceAllUsesWith(new BitCastInst(NewGEP, GEP->getType(), GEP->getName(), GEP)); continue; } // Transform things like: // getelementptr i8* bitcast ([100 x double]* X to i8*), i32 %tmp // (where tmp = 8*tmp2) into: // getelementptr [100 x double]* %arr, i32 0, i32 %tmp2; bitcast if (TD && SrcElTy->isArrayTy() && ResElTy->isIntegerTy(8)) { uint64_t ArrayEltSize = TD->getTypeAllocSize(cast<ArrayType>(SrcElTy)->getElementType()); // Check to see if "tmp" is a scale by a multiple of ArrayEltSize. We // allow either a mul, shift, or constant here. Value *NewIdx = 0; ConstantInt *Scale = 0; if (ArrayEltSize == 1) { NewIdx = GEP->getOperand(1); Scale = ConstantInt::get(cast<IntegerType>(NewIdx->getType()), 1); } else if (ConstantInt *CI = dyn_cast<ConstantInt>(GEP->getOperand(1))) { NewIdx = ConstantInt::get(CI->getType(), 1); Scale = CI; } else if (Instruction *Inst =dyn_cast<Instruction>(GEP->getOperand(1))){ if (Inst->getOpcode() == Instruction::Shl && isa<ConstantInt>(Inst->getOperand(1))) { ConstantInt *ShAmt = cast<ConstantInt>(Inst->getOperand(1)); uint32_t ShAmtVal = ShAmt->getLimitedValue(64); Scale = ConstantInt::get(cast<IntegerType>(Inst->getType()), 1ULL << ShAmtVal); NewIdx = Inst->getOperand(0); } else if (Inst->getOpcode() == Instruction::Mul && isa<ConstantInt>(Inst->getOperand(1))) { Scale = cast<ConstantInt>(Inst->getOperand(1)); NewIdx = Inst->getOperand(0); } } // If the index will be to exactly the right offset with the scale taken // out, perform the transformation. Note, we don't know whether Scale is // signed or not. We'll use unsigned version of division/modulo // operation after making sure Scale doesn't have the sign bit set. if (ArrayEltSize && Scale && Scale->getSExtValue() >= 0LL && Scale->getZExtValue() % ArrayEltSize == 0) { Scale = ConstantInt::get(Scale->getType(), Scale->getZExtValue() / ArrayEltSize); if (Scale->getZExtValue() != 1) { Constant *C = ConstantExpr::getIntegerCast(Scale, NewIdx->getType(), false /*ZExt*/); NewIdx = BinaryOperator::Create(BinaryOperator::Mul, NewIdx, C, "idxscale"); } // Insert the new GEP instruction. Value *Idx[2]; Idx[0] = Constant::getNullValue(Type::getInt32Ty(GEP->getContext())); Idx[1] = NewIdx; Value *NewGEP = GetElementPtrInst::Create(StrippedPtr, Idx, GEP->getName(), GEP); GEP->replaceAllUsesWith(new BitCastInst(NewGEP, GEP->getType(), GEP->getName(), GEP)); continue; } } } } } } } return true; }
bool PPCLoopPreIncPrep::runOnLoop(Loop *L) { bool MadeChange = false; // Only prep. the inner-most loop if (!L->empty()) return MadeChange; DEBUG(dbgs() << "PIP: Examining: " << *L << "\n"); BasicBlock *Header = L->getHeader(); const PPCSubtarget *ST = TM ? TM->getSubtargetImpl(*Header->getParent()) : nullptr; unsigned HeaderLoopPredCount = std::distance(pred_begin(Header), pred_end(Header)); // Collect buckets of comparable addresses used by loads and stores. SmallVector<Bucket, 16> Buckets; for (Loop::block_iterator I = L->block_begin(), IE = L->block_end(); I != IE; ++I) { for (BasicBlock::iterator J = (*I)->begin(), JE = (*I)->end(); J != JE; ++J) { Value *PtrValue; Instruction *MemI; if (LoadInst *LMemI = dyn_cast<LoadInst>(J)) { MemI = LMemI; PtrValue = LMemI->getPointerOperand(); } else if (StoreInst *SMemI = dyn_cast<StoreInst>(J)) { MemI = SMemI; PtrValue = SMemI->getPointerOperand(); } else if (IntrinsicInst *IMemI = dyn_cast<IntrinsicInst>(J)) { if (IMemI->getIntrinsicID() == Intrinsic::prefetch) { MemI = IMemI; PtrValue = IMemI->getArgOperand(0); } else continue; } else continue; unsigned PtrAddrSpace = PtrValue->getType()->getPointerAddressSpace(); if (PtrAddrSpace) continue; // There are no update forms for Altivec vector load/stores. if (ST && ST->hasAltivec() && PtrValue->getType()->getPointerElementType()->isVectorTy()) continue; if (L->isLoopInvariant(PtrValue)) continue; const SCEV *LSCEV = SE->getSCEVAtScope(PtrValue, L); if (const SCEVAddRecExpr *LARSCEV = dyn_cast<SCEVAddRecExpr>(LSCEV)) { if (LARSCEV->getLoop() != L) continue; } else { continue; } bool FoundBucket = false; for (auto &B : Buckets) { const SCEV *Diff = SE->getMinusSCEV(LSCEV, B.BaseSCEV); if (const auto *CDiff = dyn_cast<SCEVConstant>(Diff)) { B.Elements.push_back(BucketElement(CDiff, MemI)); FoundBucket = true; break; } } if (!FoundBucket) { if (Buckets.size() == MaxVars) return MadeChange; Buckets.push_back(Bucket(LSCEV, MemI)); } } } if (Buckets.empty()) return MadeChange; BasicBlock *LoopPredecessor = L->getLoopPredecessor(); // If there is no loop predecessor, or the loop predecessor's terminator // returns a value (which might contribute to determining the loop's // iteration space), insert a new preheader for the loop. if (!LoopPredecessor || !LoopPredecessor->getTerminator()->getType()->isVoidTy()) { LoopPredecessor = InsertPreheaderForLoop(L, DT, LI, PreserveLCSSA); if (LoopPredecessor) MadeChange = true; } if (!LoopPredecessor) return MadeChange; DEBUG(dbgs() << "PIP: Found " << Buckets.size() << " buckets\n"); SmallSet<BasicBlock *, 16> BBChanged; for (unsigned i = 0, e = Buckets.size(); i != e; ++i) { // The base address of each bucket is transformed into a phi and the others // are rewritten as offsets of that variable. // We have a choice now of which instruction's memory operand we use as the // base for the generated PHI. Always picking the first instruction in each // bucket does not work well, specifically because that instruction might // be a prefetch (and there are no pre-increment dcbt variants). Otherwise, // the choice is somewhat arbitrary, because the backend will happily // generate direct offsets from both the pre-incremented and // post-incremented pointer values. Thus, we'll pick the first non-prefetch // instruction in each bucket, and adjust the recurrence and other offsets // accordingly. for (int j = 0, je = Buckets[i].Elements.size(); j != je; ++j) { if (auto *II = dyn_cast<IntrinsicInst>(Buckets[i].Elements[j].Instr)) if (II->getIntrinsicID() == Intrinsic::prefetch) continue; // If we'd otherwise pick the first element anyway, there's nothing to do. if (j == 0) break; // If our chosen element has no offset from the base pointer, there's // nothing to do. if (!Buckets[i].Elements[j].Offset || Buckets[i].Elements[j].Offset->isZero()) break; const SCEV *Offset = Buckets[i].Elements[j].Offset; Buckets[i].BaseSCEV = SE->getAddExpr(Buckets[i].BaseSCEV, Offset); for (auto &E : Buckets[i].Elements) { if (E.Offset) E.Offset = cast<SCEVConstant>(SE->getMinusSCEV(E.Offset, Offset)); else E.Offset = cast<SCEVConstant>(SE->getNegativeSCEV(Offset)); } std::swap(Buckets[i].Elements[j], Buckets[i].Elements[0]); break; } const SCEVAddRecExpr *BasePtrSCEV = cast<SCEVAddRecExpr>(Buckets[i].BaseSCEV); if (!BasePtrSCEV->isAffine()) continue; DEBUG(dbgs() << "PIP: Transforming: " << *BasePtrSCEV << "\n"); assert(BasePtrSCEV->getLoop() == L && "AddRec for the wrong loop?"); // The instruction corresponding to the Bucket's BaseSCEV must be the first // in the vector of elements. Instruction *MemI = Buckets[i].Elements.begin()->Instr; Value *BasePtr = GetPointerOperand(MemI); assert(BasePtr && "No pointer operand"); Type *I8Ty = Type::getInt8Ty(MemI->getParent()->getContext()); Type *I8PtrTy = Type::getInt8PtrTy(MemI->getParent()->getContext(), BasePtr->getType()->getPointerAddressSpace()); const SCEV *BasePtrStartSCEV = BasePtrSCEV->getStart(); if (!SE->isLoopInvariant(BasePtrStartSCEV, L)) continue; const SCEVConstant *BasePtrIncSCEV = dyn_cast<SCEVConstant>(BasePtrSCEV->getStepRecurrence(*SE)); if (!BasePtrIncSCEV) continue; BasePtrStartSCEV = SE->getMinusSCEV(BasePtrStartSCEV, BasePtrIncSCEV); if (!isSafeToExpand(BasePtrStartSCEV, *SE)) continue; DEBUG(dbgs() << "PIP: New start is: " << *BasePtrStartSCEV << "\n"); PHINode *NewPHI = PHINode::Create(I8PtrTy, HeaderLoopPredCount, MemI->hasName() ? MemI->getName() + ".phi" : "", Header->getFirstNonPHI()); SCEVExpander SCEVE(*SE, Header->getModule()->getDataLayout(), "pistart"); Value *BasePtrStart = SCEVE.expandCodeFor(BasePtrStartSCEV, I8PtrTy, LoopPredecessor->getTerminator()); // Note that LoopPredecessor might occur in the predecessor list multiple // times, and we need to add it the right number of times. for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header); PI != PE; ++PI) { if (*PI != LoopPredecessor) continue; NewPHI->addIncoming(BasePtrStart, LoopPredecessor); } Instruction *InsPoint = &*Header->getFirstInsertionPt(); GetElementPtrInst *PtrInc = GetElementPtrInst::Create( I8Ty, NewPHI, BasePtrIncSCEV->getValue(), MemI->hasName() ? MemI->getName() + ".inc" : "", InsPoint); PtrInc->setIsInBounds(IsPtrInBounds(BasePtr)); for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header); PI != PE; ++PI) { if (*PI == LoopPredecessor) continue; NewPHI->addIncoming(PtrInc, *PI); } Instruction *NewBasePtr; if (PtrInc->getType() != BasePtr->getType()) NewBasePtr = new BitCastInst(PtrInc, BasePtr->getType(), PtrInc->hasName() ? PtrInc->getName() + ".cast" : "", InsPoint); else NewBasePtr = PtrInc; if (Instruction *IDel = dyn_cast<Instruction>(BasePtr)) BBChanged.insert(IDel->getParent()); BasePtr->replaceAllUsesWith(NewBasePtr); RecursivelyDeleteTriviallyDeadInstructions(BasePtr); // Keep track of the replacement pointer values we've inserted so that we // don't generate more pointer values than necessary. SmallPtrSet<Value *, 16> NewPtrs; NewPtrs.insert( NewBasePtr); for (auto I = std::next(Buckets[i].Elements.begin()), IE = Buckets[i].Elements.end(); I != IE; ++I) { Value *Ptr = GetPointerOperand(I->Instr); assert(Ptr && "No pointer operand"); if (NewPtrs.count(Ptr)) continue; Instruction *RealNewPtr; if (!I->Offset || I->Offset->getValue()->isZero()) { RealNewPtr = NewBasePtr; } else { Instruction *PtrIP = dyn_cast<Instruction>(Ptr); if (PtrIP && isa<Instruction>(NewBasePtr) && cast<Instruction>(NewBasePtr)->getParent() == PtrIP->getParent()) PtrIP = nullptr; else if (isa<PHINode>(PtrIP)) PtrIP = &*PtrIP->getParent()->getFirstInsertionPt(); else if (!PtrIP) PtrIP = I->Instr; GetElementPtrInst *NewPtr = GetElementPtrInst::Create( I8Ty, PtrInc, I->Offset->getValue(), I->Instr->hasName() ? I->Instr->getName() + ".off" : "", PtrIP); if (!PtrIP) NewPtr->insertAfter(cast<Instruction>(PtrInc)); NewPtr->setIsInBounds(IsPtrInBounds(Ptr)); RealNewPtr = NewPtr; } if (Instruction *IDel = dyn_cast<Instruction>(Ptr)) BBChanged.insert(IDel->getParent()); Instruction *ReplNewPtr; if (Ptr->getType() != RealNewPtr->getType()) { ReplNewPtr = new BitCastInst(RealNewPtr, Ptr->getType(), Ptr->hasName() ? Ptr->getName() + ".cast" : ""); ReplNewPtr->insertAfter(RealNewPtr); } else ReplNewPtr = RealNewPtr; Ptr->replaceAllUsesWith(ReplNewPtr); RecursivelyDeleteTriviallyDeadInstructions(Ptr); NewPtrs.insert(RealNewPtr); } MadeChange = true; } for (Loop::block_iterator I = L->block_begin(), IE = L->block_end(); I != IE; ++I) { if (BBChanged.count(*I)) DeleteDeadPHIs(*I); } return MadeChange; }
bool PPCLoopPreIncPrep::runOnLoop(Loop *L) { bool MadeChange = false; if (!DL) return MadeChange; // Only prep. the inner-most loop if (!L->empty()) return MadeChange; BasicBlock *Header = L->getHeader(); const PPCSubtarget *ST = TM ? TM->getSubtargetImpl(*Header->getParent()) : nullptr; unsigned HeaderLoopPredCount = 0; for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header); PI != PE; ++PI) { ++HeaderLoopPredCount; } // Collect buckets of comparable addresses used by loads and stores. typedef std::multimap<const SCEV *, Instruction *, SCEVLess> Bucket; SmallVector<Bucket, 16> Buckets; for (Loop::block_iterator I = L->block_begin(), IE = L->block_end(); I != IE; ++I) { for (BasicBlock::iterator J = (*I)->begin(), JE = (*I)->end(); J != JE; ++J) { Value *PtrValue; Instruction *MemI; if (LoadInst *LMemI = dyn_cast<LoadInst>(J)) { MemI = LMemI; PtrValue = LMemI->getPointerOperand(); } else if (StoreInst *SMemI = dyn_cast<StoreInst>(J)) { MemI = SMemI; PtrValue = SMemI->getPointerOperand(); } else if (IntrinsicInst *IMemI = dyn_cast<IntrinsicInst>(J)) { if (IMemI->getIntrinsicID() == Intrinsic::prefetch) { MemI = IMemI; PtrValue = IMemI->getArgOperand(0); } else continue; } else continue; unsigned PtrAddrSpace = PtrValue->getType()->getPointerAddressSpace(); if (PtrAddrSpace) continue; // There are no update forms for Altivec vector load/stores. if (ST && ST->hasAltivec() && PtrValue->getType()->getPointerElementType()->isVectorTy()) continue; if (L->isLoopInvariant(PtrValue)) continue; const SCEV *LSCEV = SE->getSCEV(PtrValue); if (!isa<SCEVAddRecExpr>(LSCEV)) continue; bool FoundBucket = false; for (unsigned i = 0, e = Buckets.size(); i != e; ++i) for (Bucket::iterator K = Buckets[i].begin(), KE = Buckets[i].end(); K != KE; ++K) { const SCEV *Diff = SE->getMinusSCEV(K->first, LSCEV); if (isa<SCEVConstant>(Diff)) { Buckets[i].insert(std::make_pair(LSCEV, MemI)); FoundBucket = true; break; } } if (!FoundBucket) { Buckets.push_back(Bucket(SCEVLess(SE))); Buckets[Buckets.size()-1].insert(std::make_pair(LSCEV, MemI)); } } } if (Buckets.empty() || Buckets.size() > MaxVars) return MadeChange; BasicBlock *LoopPredecessor = L->getLoopPredecessor(); // If there is no loop predecessor, or the loop predecessor's terminator // returns a value (which might contribute to determining the loop's // iteration space), insert a new preheader for the loop. if (!LoopPredecessor || !LoopPredecessor->getTerminator()->getType()->isVoidTy()) LoopPredecessor = InsertPreheaderForLoop(L, this); if (!LoopPredecessor) return MadeChange; SmallSet<BasicBlock *, 16> BBChanged; for (unsigned i = 0, e = Buckets.size(); i != e; ++i) { // The base address of each bucket is transformed into a phi and the others // are rewritten as offsets of that variable. const SCEVAddRecExpr *BasePtrSCEV = cast<SCEVAddRecExpr>(Buckets[i].begin()->first); if (!BasePtrSCEV->isAffine()) continue; Instruction *MemI = Buckets[i].begin()->second; Value *BasePtr = GetPointerOperand(MemI); assert(BasePtr && "No pointer operand"); Type *I8PtrTy = Type::getInt8PtrTy(MemI->getParent()->getContext(), BasePtr->getType()->getPointerAddressSpace()); const SCEV *BasePtrStartSCEV = BasePtrSCEV->getStart(); if (!SE->isLoopInvariant(BasePtrStartSCEV, L)) continue; const SCEVConstant *BasePtrIncSCEV = dyn_cast<SCEVConstant>(BasePtrSCEV->getStepRecurrence(*SE)); if (!BasePtrIncSCEV) continue; BasePtrStartSCEV = SE->getMinusSCEV(BasePtrStartSCEV, BasePtrIncSCEV); if (!isSafeToExpand(BasePtrStartSCEV, *SE)) continue; PHINode *NewPHI = PHINode::Create(I8PtrTy, HeaderLoopPredCount, MemI->hasName() ? MemI->getName() + ".phi" : "", Header->getFirstNonPHI()); SCEVExpander SCEVE(*SE, "pistart"); Value *BasePtrStart = SCEVE.expandCodeFor(BasePtrStartSCEV, I8PtrTy, LoopPredecessor->getTerminator()); // Note that LoopPredecessor might occur in the predecessor list multiple // times, and we need to add it the right number of times. for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header); PI != PE; ++PI) { if (*PI != LoopPredecessor) continue; NewPHI->addIncoming(BasePtrStart, LoopPredecessor); } Instruction *InsPoint = Header->getFirstInsertionPt(); GetElementPtrInst *PtrInc = GetElementPtrInst::Create(NewPHI, BasePtrIncSCEV->getValue(), MemI->hasName() ? MemI->getName() + ".inc" : "", InsPoint); PtrInc->setIsInBounds(IsPtrInBounds(BasePtr)); for (pred_iterator PI = pred_begin(Header), PE = pred_end(Header); PI != PE; ++PI) { if (*PI == LoopPredecessor) continue; NewPHI->addIncoming(PtrInc, *PI); } Instruction *NewBasePtr; if (PtrInc->getType() != BasePtr->getType()) NewBasePtr = new BitCastInst(PtrInc, BasePtr->getType(), PtrInc->hasName() ? PtrInc->getName() + ".cast" : "", InsPoint); else NewBasePtr = PtrInc; if (Instruction *IDel = dyn_cast<Instruction>(BasePtr)) BBChanged.insert(IDel->getParent()); BasePtr->replaceAllUsesWith(NewBasePtr); RecursivelyDeleteTriviallyDeadInstructions(BasePtr); Value *LastNewPtr = NewBasePtr; for (Bucket::iterator I = std::next(Buckets[i].begin()), IE = Buckets[i].end(); I != IE; ++I) { Value *Ptr = GetPointerOperand(I->second); assert(Ptr && "No pointer operand"); if (Ptr == LastNewPtr) continue; Instruction *RealNewPtr; const SCEVConstant *Diff = cast<SCEVConstant>(SE->getMinusSCEV(I->first, BasePtrSCEV)); if (Diff->isZero()) { RealNewPtr = NewBasePtr; } else { Instruction *PtrIP = dyn_cast<Instruction>(Ptr); if (PtrIP && isa<Instruction>(NewBasePtr) && cast<Instruction>(NewBasePtr)->getParent() == PtrIP->getParent()) PtrIP = 0; else if (isa<PHINode>(PtrIP)) PtrIP = PtrIP->getParent()->getFirstInsertionPt(); else if (!PtrIP) PtrIP = I->second; GetElementPtrInst *NewPtr = GetElementPtrInst::Create(PtrInc, Diff->getValue(), I->second->hasName() ? I->second->getName() + ".off" : "", PtrIP); if (!PtrIP) NewPtr->insertAfter(cast<Instruction>(PtrInc)); NewPtr->setIsInBounds(IsPtrInBounds(Ptr)); RealNewPtr = NewPtr; } if (Instruction *IDel = dyn_cast<Instruction>(Ptr)) BBChanged.insert(IDel->getParent()); Instruction *ReplNewPtr; if (Ptr->getType() != RealNewPtr->getType()) { ReplNewPtr = new BitCastInst(RealNewPtr, Ptr->getType(), Ptr->hasName() ? Ptr->getName() + ".cast" : ""); ReplNewPtr->insertAfter(RealNewPtr); } else ReplNewPtr = RealNewPtr; Ptr->replaceAllUsesWith(ReplNewPtr); RecursivelyDeleteTriviallyDeadInstructions(Ptr); LastNewPtr = RealNewPtr; } MadeChange = true; } for (Loop::block_iterator I = L->block_begin(), IE = L->block_end(); I != IE; ++I) { if (BBChanged.count(*I)) DeleteDeadPHIs(*I); } return MadeChange; }
bool Aa::LowerGepPass::runOnFunction(Function &F) { const llvm::Type *ptr_int_type = TD->getIntPtrType(F.getContext()); for (Function::iterator bi = F.begin(), be = F.end(); bi != be; ++bi) { BasicBlock *bb = bi; BasicBlock::iterator ii = bb->begin(); while (ii != bb->end()) { GetElementPtrInst *gep = dyn_cast<GetElementPtrInst>(ii); BasicBlock::iterator gi = ii++; if (!gep) { continue; } for (llvm::Value::use_iterator ui = gep->use_begin(), ue = gep->use_end(); ui != ue; ++ui) { Use &u = ui.getUse(); IOCode ioc = get_io_code(u); if (ioc == NOT_IO) continue; u.set(CastInst::CreatePointerCast(gep->getPointerOperand() , gep->getType() , "", gep)); } assert(gep->hasIndices() && "GEP without indices??"); llvm::Value *ptr = gep->getPointerOperand(); const Type *ctype = ptr->getType(); // deal with the base pointer first llvm::Value *base = gep->getPointerOperand(); std::string base_name = gep->getNameStr() + ".base"; llvm::Value *address = new PtrToIntInst(base, ptr_int_type, base_name + ".cast", gi); unsigned i = 0; for (User::op_iterator oi = gep->idx_begin(), oe = gep->idx_end(); oi != oe; ++oi, ++i) { llvm::Value *index = *oi; llvm::Value *offset = NULL; std::stringstream index_name; index_name << gep->getNameStr() << ".idx." << i; if (const SequentialType *qtype = dyn_cast<SequentialType>(ctype)) { // multiply index by size of element unsigned element_size = getTypePaddedSize(TD, qtype->getElementType()); const llvm::IntegerType *index_type = cast<IntegerType>(index->getType()); ConstantInt *cint = ConstantInt::get(index_type, element_size); assert(cint && "uh oh!"); offset = BinaryOperator::Create(Instruction::Mul , cint , index , index_name.str() , gi); ctype = qtype->getElementType(); } else if (const StructType *stype = dyn_cast<StructType>(ctype)) { // calculate offset into the struct const StructLayout *layout = TD->getStructLayout(stype); unsigned idx = cast<ConstantInt>(index)->getValue().getZExtValue(); unsigned struct_offset = layout->getElementOffset(idx); offset = ConstantInt::get(ptr_int_type, struct_offset); ctype = stype->getElementType(idx); } else assert(false && "unhandled offset into composite type"); // add offset to the address assert(address && "uh oh!"); std::stringstream add_name; add_name << gep->getNameStr() << ".lvl." << i; if (offset->getType() != address->getType()) { offset = CastInst::CreateIntegerCast(offset, address->getType() , false, offset->getName() + ".resized" , gi); } address = BinaryOperator::Create(Instruction::Add , address, offset , add_name.str(), gi); } if (address->getType() != ptr_int_type) address = CastInst::CreateIntegerCast(address, ptr_int_type , false, address->getName() + ".final", gi); Instruction *new_ptr = new IntToPtrInst(address, gep->getType() , gep->getName() + ".cast"); ReplaceInstWithInst(bb->getInstList(), gi, new_ptr); } } return true; }
// // Methods: insertBadIndexing() // // Description: // This method modifieds GEP indexing expressions so that their indices are // (most likely) below the bounds of the object pointed to by the source // pointer. It does this by modifying the first index to be -1. // // Return value: // true - One or more changes were made to the program. // false - No changes were made to the program. // bool FaultInjector::insertBadIndexing (Function & F) { // Worklist of allocation sites to rewrite std::vector<GetElementPtrInst *> WorkList; // // Find GEP instructions that index into an array. Add these to the // worklist. // for (Function::iterator fI = F.begin(), fE = F.end(); fI != fE; ++fI) { BasicBlock & BB = *fI; for (BasicBlock::iterator I = BB.begin(), bE = BB.end(); I != bE; ++I) { if (GetElementPtrInst * GEP = dyn_cast<GetElementPtrInst>(I)) { // Skip if we should not insert a fault. if (!doFault()) continue; WorkList.push_back (GEP); } } } // Flag whether the program was modified bool modified = (WorkList.size() > 0); // // Iterator through the worklist and transform each GEP. // while (WorkList.size()) { GetElementPtrInst * GEP = WorkList.back(); WorkList.pop_back(); // // Print out where the fault will be inserted in the source code. // printSourceInfo ("Bad indexing", GEP); // The index arguments to the new GEP std::vector<Value *> args; // // Create a copy of the GEP's indices. // User::op_iterator i = GEP->idx_begin(); if (i == GEP->idx_end()) continue; args.push_back (ConstantInt::get (Int32Type, INT_MAX, true)); for (++i; i != GEP->idx_end(); ++i) { args.push_back (*i); } // // Create the new GEP instruction. // Value * Pointer = GEP->getPointerOperand(); Twine name = GEP->getName() + "badindex"; GetElementPtrInst * NewGEP = GetElementPtrInst::Create (Pointer, args.begin(), args.end(), name, GEP); GEP->replaceAllUsesWith (NewGEP); GEP->eraseFromParent(); ++BadIndices; } return modified; }