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
8namespace llvm {
9Type *GEPOperator::getSourceElementType() const {
10  if (auto *I = dyn_cast<GetElementPtrInst>(this))
11    return I->getSourceElementType();
12  return cast<GetElementPtrConstantExpr>(this)->getSourceElementType();
13}
14
15bool 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