- case Intrinsic::objectsize: {
- const Type *ReturnTy = CI.getType();
- Value *Op1 = II->getOperand(1);
-
- // If we're a constant expr then we just return the number of bytes
- // left in whatever we're indexing. Since it's constant there's no
- // need for maximum or minimum bytes.
- if (ConstantExpr *CE = dyn_cast<ConstantExpr>(Op1)) {
- // If this isn't a GEP give up.
- if (CE->getOpcode() != Instruction::GetElementPtr) return 0;
-
- const PointerType *ObjTy =
- reinterpret_cast<const PointerType*>(CE->getOperand(0)->getType());
-
- if (const ArrayType *AT = dyn_cast<ArrayType>(ObjTy->getElementType())) {
-
- // Deal with multi-dimensional arrays
- const ArrayType *SAT = AT;
- while ((AT = dyn_cast<ArrayType>(AT->getElementType())))
- SAT = AT;
-
- size_t numElems = SAT->getNumElements();
-
- // If numElems is 0, we don't know how large the array is so we can't
- // make any determinations yet.
- if (numElems == 0) break;
-
- // We return the remaining bytes, so grab the size of an element
- // in bytes.
- size_t sizeofElem = SAT->getElementType()->getPrimitiveSizeInBits() / 8;
-
- ConstantInt *Const =
- cast<ConstantInt>(CE->getOperand(CE->getNumOperands() - 1));
- size_t indx = Const->getZExtValue();
- return ReplaceInstUsesWith(CI,
- ConstantInt::get(ReturnTy,
- ((numElems - indx) * sizeofElem)));
- }
- }
- // TODO: Add more types here.
- }