104 lines
3.9 KiB
C++
104 lines
3.9 KiB
C++
//===- Local.h - Functions to perform local transformations -----*- C++ -*-===//
|
|
//
|
|
// 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.
|
|
//
|
|
//===----------------------------------------------------------------------===//
|
|
|
|
#ifndef LLVM_ANALYSIS_UTILS_LOCAL_H
|
|
#define LLVM_ANALYSIS_UTILS_LOCAL_H
|
|
|
|
#include "llvm/ADT/StringRef.h"
|
|
#include "llvm/IR/DataLayout.h"
|
|
#include "llvm/IR/GetElementPtrTypeIterator.h"
|
|
|
|
namespace llvm {
|
|
|
|
/// Given a getelementptr instruction/constantexpr, emit the code necessary to
|
|
/// compute the offset from the base pointer (without adding in the base
|
|
/// pointer). Return the result as a signed integer of intptr size.
|
|
/// When NoAssumptions is true, no assumptions about index computation not
|
|
/// overflowing is made.
|
|
template <typename IRBuilderTy>
|
|
Value *EmitGEPOffset(IRBuilderTy *Builder, const DataLayout &DL, User *GEP,
|
|
bool NoAssumptions = false) {
|
|
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;
|
|
|
|
// Build a mask for high order bits.
|
|
unsigned IntPtrWidth = IntIdxTy->getScalarType()->getIntegerBitWidth();
|
|
uint64_t PtrSizeMask =
|
|
std::numeric_limits<uint64_t>::max() >> (64 - IntPtrWidth);
|
|
|
|
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;
|
|
uint64_t Size = DL.getTypeAllocSize(GTI.getIndexedType()) & PtrSizeMask;
|
|
Value *Offset;
|
|
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();
|
|
Size = DL.getStructLayout(STy)->getElementOffset(OpValue);
|
|
if (!Size)
|
|
continue;
|
|
|
|
Offset = ConstantInt::get(IntIdxTy, Size);
|
|
} else {
|
|
// Splat the constant if needed.
|
|
if (IntIdxTy->isVectorTy() && !OpC->getType()->isVectorTy())
|
|
OpC = ConstantVector::getSplat(
|
|
cast<VectorType>(IntIdxTy)->getElementCount(), OpC);
|
|
|
|
Constant *Scale = ConstantInt::get(IntIdxTy, Size);
|
|
Constant *OC =
|
|
ConstantExpr::getIntegerCast(OpC, IntIdxTy, true /*SExt*/);
|
|
Offset =
|
|
ConstantExpr::getMul(OC, Scale, false /*NUW*/, isInBounds /*NSW*/);
|
|
}
|
|
} else {
|
|
// Splat the index if needed.
|
|
if (IntIdxTy->isVectorTy() && !Op->getType()->isVectorTy())
|
|
Op = Builder->CreateVectorSplat(
|
|
cast<FixedVectorType>(IntIdxTy)->getNumElements(), Op);
|
|
|
|
// Convert to correct type.
|
|
if (Op->getType() != IntIdxTy)
|
|
Op = Builder->CreateIntCast(Op, IntIdxTy, true, Op->getName().str()+".c");
|
|
if (Size != 1) {
|
|
// We'll let instcombine(mul) convert this to a shl if possible.
|
|
Op = Builder->CreateMul(Op, ConstantInt::get(IntIdxTy, Size),
|
|
GEP->getName().str() + ".idx", false /*NUW*/,
|
|
isInBounds /*NSW*/);
|
|
}
|
|
Offset = Op;
|
|
}
|
|
|
|
if (Result)
|
|
Result = Builder->CreateAdd(Result, Offset, GEP->getName().str()+".offs",
|
|
false /*NUW*/, isInBounds /*NSW*/);
|
|
else
|
|
Result = Offset;
|
|
}
|
|
return Result ? Result : Constant::getNullValue(IntIdxTy);
|
|
}
|
|
|
|
}
|
|
|
|
#endif // LLVM_TRANSFORMS_UTILS_LOCAL_H
|