45 lines
1.5 KiB
C++
45 lines
1.5 KiB
C++
#include "llvm/IR/Operator.h"
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#include "llvm/IR/GetElementPtrTypeIterator.h"
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#include "llvm/IR/Instructions.h"
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#include "llvm/IR/Type.h"
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#include "ConstantsContext.h"
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namespace llvm {
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Type *GEPOperator::getSourceElementType() const {
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if (auto *I = dyn_cast<GetElementPtrInst>(this))
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return I->getSourceElementType();
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return cast<GetElementPtrConstantExpr>(this)->getSourceElementType();
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}
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bool GEPOperator::accumulateConstantOffset(const DataLayout &DL,
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APInt &Offset) const {
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assert(Offset.getBitWidth() ==
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DL.getPointerSizeInBits(getPointerAddressSpace()) &&
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"The offset must have exactly as many bits as our pointer.");
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for (gep_type_iterator GTI = gep_type_begin(this), GTE = gep_type_end(this);
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GTI != GTE; ++GTI) {
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ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand());
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if (!OpC)
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return false;
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if (OpC->isZero())
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continue;
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// Handle a struct index, which adds its field offset to the pointer.
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if (StructType *STy = dyn_cast<StructType>(*GTI)) {
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unsigned ElementIdx = OpC->getZExtValue();
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const StructLayout *SL = DL.getStructLayout(STy);
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Offset += APInt(Offset.getBitWidth(), SL->getElementOffset(ElementIdx));
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continue;
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}
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// For array or vector indices, scale the index by the size of the type.
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APInt Index = OpC->getValue().sextOrTrunc(Offset.getBitWidth());
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Offset += Index * APInt(Offset.getBitWidth(),
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DL.getTypeAllocSize(GTI.getIndexedType()));
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}
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return true;
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}
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}
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