| //===- Local.cpp - Functions to perform local transformations -------------===// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This family of functions perform various local transformations to the |
| // program. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/Analysis/Utils/Local.h" |
| #include "llvm/ADT/Twine.h" |
| #include "llvm/IR/DataLayout.h" |
| #include "llvm/IR/GetElementPtrTypeIterator.h" |
| #include "llvm/IR/IRBuilder.h" |
| |
| using namespace llvm; |
| |
| Value *llvm::emitGEPOffset(IRBuilderBase *Builder, const DataLayout &DL, |
| User *GEP, bool NoAssumptions) { |
| GEPOperator *GEPOp = cast<GEPOperator>(GEP); |
| Type *IntIdxTy = DL.getIndexType(GEP->getType()); |
| Value *Result = nullptr; |
| |
| // If the GEP is inbounds, we know that none of the addressing operations will |
| // overflow in a signed sense. |
| bool isInBounds = GEPOp->isInBounds() && !NoAssumptions; |
| auto AddOffset = [&](Value *Offset) { |
| if (Result) |
| Result = Builder->CreateAdd(Result, Offset, GEP->getName() + ".offs", |
| false /*NUW*/, isInBounds /*NSW*/); |
| else |
| Result = Offset; |
| }; |
| |
| gep_type_iterator GTI = gep_type_begin(GEP); |
| for (User::op_iterator i = GEP->op_begin() + 1, e = GEP->op_end(); i != e; |
| ++i, ++GTI) { |
| Value *Op = *i; |
| if (Constant *OpC = dyn_cast<Constant>(Op)) { |
| if (OpC->isZeroValue()) |
| continue; |
| |
| // Handle a struct index, which adds its field offset to the pointer. |
| if (StructType *STy = GTI.getStructTypeOrNull()) { |
| uint64_t OpValue = OpC->getUniqueInteger().getZExtValue(); |
| uint64_t Size = DL.getStructLayout(STy)->getElementOffset(OpValue); |
| if (!Size) |
| continue; |
| |
| AddOffset(ConstantInt::get(IntIdxTy, Size)); |
| continue; |
| } |
| } |
| |
| // Splat the index if needed. |
| if (IntIdxTy->isVectorTy() && !Op->getType()->isVectorTy()) |
| Op = Builder->CreateVectorSplat( |
| cast<VectorType>(IntIdxTy)->getElementCount(), Op); |
| |
| // Convert to correct type. |
| if (Op->getType() != IntIdxTy) |
| Op = Builder->CreateIntCast(Op, IntIdxTy, true, Op->getName() + ".c"); |
| TypeSize TSize = GTI.getSequentialElementStride(DL); |
| if (TSize != TypeSize::getFixed(1)) { |
| Value *Scale = Builder->CreateTypeSize(IntIdxTy->getScalarType(), TSize); |
| if (IntIdxTy->isVectorTy()) |
| Scale = Builder->CreateVectorSplat( |
| cast<VectorType>(IntIdxTy)->getElementCount(), Scale); |
| // We'll let instcombine(mul) convert this to a shl if possible. |
| Op = Builder->CreateMul(Op, Scale, GEP->getName() + ".idx", false /*NUW*/, |
| isInBounds /*NSW*/); |
| } |
| AddOffset(Op); |
| } |
| return Result ? Result : Constant::getNullValue(IntIdxTy); |
| } |