1 #include "llvm/IR/Operator.h" 2 #include "llvm/IR/GetElementPtrTypeIterator.h" 3 #include "llvm/IR/Instructions.h" 4 #include "llvm/IR/Type.h" 5 6 #include "ConstantsContext.h" 7 8 namespace llvm { 9 Type *GEPOperator::getSourceElementType() const { 10 if (auto *I = dyn_cast<GetElementPtrInst>(this)) 11 return I->getSourceElementType(); 12 return cast<GetElementPtrConstantExpr>(this)->getSourceElementType(); 13 } 14 15 Type *GEPOperator::getResultElementType() const { 16 if (auto *I = dyn_cast<GetElementPtrInst>(this)) 17 return I->getResultElementType(); 18 return cast<GetElementPtrConstantExpr>(this)->getResultElementType(); 19 } 20 21 bool GEPOperator::accumulateConstantOffset(const DataLayout &DL, 22 APInt &Offset) const { 23 assert(Offset.getBitWidth() == 24 DL.getPointerSizeInBits(getPointerAddressSpace()) && 25 "The offset must have exactly as many bits as our pointer."); 26 27 for (gep_type_iterator GTI = gep_type_begin(this), GTE = gep_type_end(this); 28 GTI != GTE; ++GTI) { 29 ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand()); 30 if (!OpC) 31 return false; 32 if (OpC->isZero()) 33 continue; 34 35 // Handle a struct index, which adds its field offset to the pointer. 36 if (StructType *STy = dyn_cast<StructType>(*GTI)) { 37 unsigned ElementIdx = OpC->getZExtValue(); 38 const StructLayout *SL = DL.getStructLayout(STy); 39 Offset += APInt(Offset.getBitWidth(), SL->getElementOffset(ElementIdx)); 40 continue; 41 } 42 43 // For array or vector indices, scale the index by the size of the type. 44 APInt Index = OpC->getValue().sextOrTrunc(Offset.getBitWidth()); 45 Offset += Index * APInt(Offset.getBitWidth(), 46 DL.getTypeAllocSize(GTI.getIndexedType())); 47 } 48 return true; 49 } 50 } 51
