implement support for reading aggregate constants, including handling forward
constant references, etc.
git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36391 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/lib/Bitcode/Reader/BitcodeReader.cpp b/lib/Bitcode/Reader/BitcodeReader.cpp
index d974ace..fa75e00 100644
--- a/lib/Bitcode/Reader/BitcodeReader.cpp
+++ b/lib/Bitcode/Reader/BitcodeReader.cpp
@@ -55,6 +55,39 @@
}
}
+namespace {
+ /// @brief A class for maintaining the slot number definition
+ /// as a placeholder for the actual definition for forward constants defs.
+ class ConstantPlaceHolder : public ConstantExpr {
+ ConstantPlaceHolder(); // DO NOT IMPLEMENT
+ void operator=(const ConstantPlaceHolder &); // DO NOT IMPLEMENT
+public:
+ Use Op;
+ ConstantPlaceHolder(const Type *Ty)
+ : ConstantExpr(Ty, Instruction::UserOp1, &Op, 1),
+ Op(UndefValue::get(Type::Int32Ty), this) {
+ }
+ };
+}
+
+Constant *BitcodeReaderValueList::getConstantFwdRef(unsigned Idx,
+ const Type *Ty) {
+ if (Idx >= size()) {
+ // Insert a bunch of null values.
+ Uses.resize(Idx+1);
+ OperandList = &Uses[0];
+ NumOperands = Idx+1;
+ }
+
+ if (Uses[Idx])
+ return cast<Constant>(getOperand(Idx));
+
+ // Create and return a placeholder, which will later be RAUW'd.
+ Constant *C = new ConstantPlaceHolder(Ty);
+ Uses[Idx].init(C, this);
+ return C;
+}
+
const Type *BitcodeReader::getTypeByID(unsigned ID, bool isTypeTable) {
// If the TypeID is in range, return it.
@@ -324,6 +357,7 @@
// Read all the records for this value table.
const Type *CurTy = Type::Int32Ty;
+ unsigned NextCstNo = ValueList.size();
while (1) {
unsigned Code = Stream.ReadCode();
if (Code == bitc::END_BLOCK) {
@@ -341,6 +375,9 @@
}
}
+ if (NextCstNo != ValueList.size())
+ return Error("Invalid constant reference!");
+
return Stream.ReadBlockEnd();
}
@@ -403,9 +440,48 @@
else
V = UndefValue::get(CurTy);
break;
+
+ case bitc::CST_CODE_AGGREGATE: {// AGGREGATE: [n, n x value number]
+ if (Record.empty() || Record.size() < Record[0]+1)
+ return Error("Invalid CST_AGGREGATE record");
+
+ unsigned Size = Record[0];
+ std::vector<Constant*> Elts;
+
+ if (const StructType *STy = dyn_cast<StructType>(CurTy)) {
+ for (unsigned i = 0; i != Size; ++i)
+ Elts.push_back(ValueList.getConstantFwdRef(Record[i+1],
+ STy->getElementType(i)));
+ V = ConstantStruct::get(STy, Elts);
+ } else if (const ArrayType *ATy = dyn_cast<ArrayType>(CurTy)) {
+ const Type *EltTy = ATy->getElementType();
+ for (unsigned i = 0; i != Size; ++i)
+ Elts.push_back(ValueList.getConstantFwdRef(Record[i+1], EltTy));
+ V = ConstantArray::get(ATy, Elts);
+ } else if (const VectorType *VTy = dyn_cast<VectorType>(CurTy)) {
+ const Type *EltTy = VTy->getElementType();
+ for (unsigned i = 0; i != Size; ++i)
+ Elts.push_back(ValueList.getConstantFwdRef(Record[i+1], EltTy));
+ V = ConstantVector::get(Elts);
+ } else {
+ V = UndefValue::get(CurTy);
+ }
+ }
}
- ValueList.push_back(V);
+ if (NextCstNo == ValueList.size())
+ ValueList.push_back(V);
+ else if (ValueList[NextCstNo] == 0)
+ ValueList.initVal(NextCstNo, V);
+ else {
+ // If there was a forward reference to this constant,
+ Value *OldV = ValueList[NextCstNo];
+ ValueList.setOperand(NextCstNo, V);
+ OldV->replaceAllUsesWith(V);
+ delete OldV;
+ }
+
+ ++NextCstNo;
}
}