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 bool GEPOperator::accumulateConstantOffset(const DataLayout &DL, 16 APInt &Offset) const { 17 assert(Offset.getBitWidth() == 18 DL.getPointerSizeInBits(getPointerAddressSpace()) && 19 "The offset must have exactly as many bits as our pointer."); 20 21 for (gep_type_iterator GTI = gep_type_begin(this), GTE = gep_type_end(this); 22 GTI != GTE; ++GTI) { 23 ConstantInt *OpC = dyn_cast<ConstantInt>(GTI.getOperand()); 24 if (!OpC) 25 return false; 26 if (OpC->isZero()) 27 continue; 28 29 // Handle a struct index, which adds its field offset to the pointer. 30 if (StructType *STy = dyn_cast<StructType>(*GTI)) { 31 unsigned ElementIdx = OpC->getZExtValue(); 32 const StructLayout *SL = DL.getStructLayout(STy); 33 Offset += APInt(Offset.getBitWidth(), SL->getElementOffset(ElementIdx)); 34 continue; 35 } 36 37 // For array or vector indices, scale the index by the size of the type. 38 APInt Index = OpC->getValue().sextOrTrunc(Offset.getBitWidth()); 39 Offset += Index * APInt(Offset.getBitWidth(), 40 DL.getTypeAllocSize(GTI.getIndexedType())); 41 } 42 return true; 43 } 44 } 45
