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implement support for reading aggregate constants, including handling forward

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constant references, etc.


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@36391 91177308-0d34-0410-b5e6-96231b3b80d8
This commit is contained in:
Chris Lattner
2007-04-24 05:48:56 +00:00
parent 0eef08046e
commit 522b7b104c
2 changed files with 108 additions and 5 deletions
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78
lib/Bitcode/Reader/BitcodeReader.cpp
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@ -55,6 +55,39 @@ static GlobalValue::VisibilityTypes GetDecodedVisibility(unsigned Val) {
}
}
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 @@ bool BitcodeReader::ParseConstants(BitstreamReader &Stream) {
// 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 @@ bool BitcodeReader::ParseConstants(BitstreamReader &Stream) {
}
}
if (NextCstNo != ValueList.size())
return Error("Invalid constant reference!");
return Stream.ReadBlockEnd();
}
@ -403,9 +440,48 @@ bool BitcodeReader::ParseConstants(BitstreamReader &Stream) {
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;
}
}