llvm-6502/lib/Bytecode/Reader/ConstantReader.cpp

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//===- ConstantReader.cpp - Code to constants and types ====---------------===//
//
// The LLVM Compiler Infrastructure
//
// This file was developed by the LLVM research group and is distributed under
// the University of Illinois Open Source License. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// This file implements functionality to deserialize constants and types from
// bytecode files.
//
//===----------------------------------------------------------------------===//
#include "ReaderInternals.h"
#include "llvm/Module.h"
#include "llvm/Constants.h"
#include <algorithm>
using namespace llvm;
const Type *BytecodeParser::parseTypeConstant(const unsigned char *&Buf,
const unsigned char *EndBuf) {
unsigned PrimType = read_vbr_uint(Buf, EndBuf);
const Type *Val = 0;
if ((Val = Type::getPrimitiveType((Type::PrimitiveID)PrimType)))
return Val;
switch (PrimType) {
case Type::FunctionTyID: {
const Type *RetType = getType(read_vbr_uint(Buf, EndBuf));
unsigned NumParams = read_vbr_uint(Buf, EndBuf);
std::vector<const Type*> Params;
while (NumParams--)
Params.push_back(getType(read_vbr_uint(Buf, EndBuf)));
bool isVarArg = Params.size() && Params.back() == Type::VoidTy;
if (isVarArg) Params.pop_back();
return FunctionType::get(RetType, Params, isVarArg);
}
case Type::ArrayTyID: {
unsigned ElTyp = read_vbr_uint(Buf, EndBuf);
const Type *ElementType = getType(ElTyp);
unsigned NumElements = read_vbr_uint(Buf, EndBuf);
BCR_TRACE(5, "Array Type Constant #" << ElTyp << " size="
<< NumElements << "\n");
return ArrayType::get(ElementType, NumElements);
}
case Type::StructTyID: {
std::vector<const Type*> Elements;
unsigned Typ = read_vbr_uint(Buf, EndBuf);
while (Typ) { // List is terminated by void/0 typeid
Elements.push_back(getType(Typ));
Typ = read_vbr_uint(Buf, EndBuf);
}
return StructType::get(Elements);
}
case Type::PointerTyID: {
unsigned ElTyp = read_vbr_uint(Buf, EndBuf);
BCR_TRACE(5, "Pointer Type Constant #" << ElTyp << "\n");
return PointerType::get(getType(ElTyp));
}
case Type::OpaqueTyID: {
return OpaqueType::get();
}
default:
std::cerr << __FILE__ << ":" << __LINE__
<< ": Don't know how to deserialize"
<< " primitive Type " << PrimType << "\n";
return Val;
}
}
// parseTypeConstants - We have to use this weird code to handle recursive
// types. We know that recursive types will only reference the current slab of
// values in the type plane, but they can forward reference types before they
// have been read. For example, Type #0 might be '{ Ty#1 }' and Type #1 might
// be 'Ty#0*'. When reading Type #0, type number one doesn't exist. To fix
// this ugly problem, we pessimistically insert an opaque type for each type we
// are about to read. This means that forward references will resolve to
// something and when we reread the type later, we can replace the opaque type
// with a new resolved concrete type.
//
void BytecodeParser::parseTypeConstants(const unsigned char *&Buf,
const unsigned char *EndBuf,
TypeValuesListTy &Tab,
unsigned NumEntries) {
assert(Tab.size() == 0 && "should not have read type constants in before!");
// Insert a bunch of opaque types to be resolved later...
Tab.reserve(NumEntries);
for (unsigned i = 0; i != NumEntries; ++i)
Tab.push_back(OpaqueType::get());
// Loop through reading all of the types. Forward types will make use of the
// opaque types just inserted.
//
for (unsigned i = 0; i != NumEntries; ++i) {
const Type *NewTy = parseTypeConstant(Buf, EndBuf), *OldTy = Tab[i].get();
if (NewTy == 0) throw std::string("Couldn't parse type!");
BCR_TRACE(4, "#" << i << ": Read Type Constant: '" << NewTy <<
"' Replacing: " << OldTy << "\n");
// Don't insertValue the new type... instead we want to replace the opaque
// type with the new concrete value...
//
// Refine the abstract type to the new type. This causes all uses of the
// abstract type to use NewTy. This also will cause the opaque type to be
// deleted...
//
cast<DerivedType>(const_cast<Type*>(OldTy))->refineAbstractTypeTo(NewTy);
// This should have replace the old opaque type with the new type in the
// value table... or with a preexisting type that was already in the system
assert(Tab[i] != OldTy && "refineAbstractType didn't work!");
}
BCR_TRACE(5, "Resulting types:\n");
for (unsigned i = 0; i < NumEntries; ++i) {
BCR_TRACE(5, (void*)Tab[i].get() << " - " << Tab[i].get() << "\n");
}
}
Constant *BytecodeParser::parseConstantValue(const unsigned char *&Buf,
const unsigned char *EndBuf,
unsigned TypeID) {
// We must check for a ConstantExpr before switching by type because
// a ConstantExpr can be of any type, and has no explicit value.
//
// 0 if not expr; numArgs if is expr
unsigned isExprNumArgs = read_vbr_uint(Buf, EndBuf);
if (isExprNumArgs) {
// FIXME: Encoding of constant exprs could be much more compact!
std::vector<Constant*> ArgVec;
ArgVec.reserve(isExprNumArgs);
unsigned Opcode = read_vbr_uint(Buf, EndBuf);
// Read the slot number and types of each of the arguments
for (unsigned i = 0; i != isExprNumArgs; ++i) {
unsigned ArgValSlot = read_vbr_uint(Buf, EndBuf);
unsigned ArgTypeSlot = read_vbr_uint(Buf, EndBuf);
BCR_TRACE(4, "CE Arg " << i << ": Type: '" << *getType(ArgTypeSlot)
<< "' slot: " << ArgValSlot << "\n");
// Get the arg value from its slot if it exists, otherwise a placeholder
ArgVec.push_back(getConstantValue(ArgTypeSlot, ArgValSlot));
}
// Construct a ConstantExpr of the appropriate kind
if (isExprNumArgs == 1) { // All one-operand expressions
assert(Opcode == Instruction::Cast);
return ConstantExpr::getCast(ArgVec[0], getType(TypeID));
} else if (Opcode == Instruction::GetElementPtr) { // GetElementPtr
std::vector<Constant*> IdxList(ArgVec.begin()+1, ArgVec.end());
return ConstantExpr::getGetElementPtr(ArgVec[0], IdxList);
} else { // All other 2-operand expressions
return ConstantExpr::get(Opcode, ArgVec[0], ArgVec[1]);
}
}
// Ok, not an ConstantExpr. We now know how to read the given type...
const Type *Ty = getType(TypeID);
switch (Ty->getPrimitiveID()) {
case Type::BoolTyID: {
unsigned Val = read_vbr_uint(Buf, EndBuf);
if (Val != 0 && Val != 1) throw std::string("Invalid boolean value read.");
return ConstantBool::get(Val == 1);
}
case Type::UByteTyID: // Unsigned integer types...
case Type::UShortTyID:
case Type::UIntTyID: {
unsigned Val = read_vbr_uint(Buf, EndBuf);
if (!ConstantUInt::isValueValidForType(Ty, Val))
throw std::string("Invalid unsigned byte/short/int read.");
return ConstantUInt::get(Ty, Val);
}
case Type::ULongTyID: {
return ConstantUInt::get(Ty, read_vbr_uint64(Buf, EndBuf));
}
case Type::SByteTyID: // Signed integer types...
case Type::ShortTyID:
case Type::IntTyID: {
case Type::LongTyID:
int64_t Val = read_vbr_int64(Buf, EndBuf);
if (!ConstantSInt::isValueValidForType(Ty, Val))
throw std::string("Invalid signed byte/short/int/long read.");
return ConstantSInt::get(Ty, Val);
}
case Type::FloatTyID: {
float F;
input_data(Buf, EndBuf, &F, &F+1);
return ConstantFP::get(Ty, F);
}
case Type::DoubleTyID: {
double Val;
input_data(Buf, EndBuf, &Val, &Val+1);
return ConstantFP::get(Ty, Val);
}
case Type::TypeTyID:
throw std::string("Type constants shouldn't live in constant table!");
case Type::ArrayTyID: {
const ArrayType *AT = cast<ArrayType>(Ty);
unsigned NumElements = AT->getNumElements();
unsigned TypeSlot = getTypeSlot(AT->getElementType());
std::vector<Constant*> Elements;
Elements.reserve(NumElements);
while (NumElements--) // Read all of the elements of the constant.
Elements.push_back(getConstantValue(TypeSlot,
read_vbr_uint(Buf, EndBuf)));
return ConstantArray::get(AT, Elements);
}
case Type::StructTyID: {
const StructType *ST = cast<StructType>(Ty);
std::vector<Constant *> Elements;
Elements.reserve(ST->getNumElements());
for (unsigned i = 0; i != ST->getNumElements(); ++i)
Elements.push_back(getConstantValue(ST->getElementType(i),
read_vbr_uint(Buf, EndBuf)));
return ConstantStruct::get(ST, Elements);
}
case Type::PointerTyID: { // ConstantPointerRef value...
const PointerType *PT = cast<PointerType>(Ty);
unsigned Slot = read_vbr_uint(Buf, EndBuf);
BCR_TRACE(4, "CPR: Type: '" << Ty << "' slot: " << Slot << "\n");
// Check to see if we have already read this global variable...
Value *Val = getValue(TypeID, Slot, false);
GlobalValue *GV;
if (Val) {
if (!(GV = dyn_cast<GlobalValue>(Val)))
throw std::string("Value of ConstantPointerRef not in ValueTable!");
BCR_TRACE(5, "Value Found in ValueTable!\n");
} else {
throw std::string("Forward references are not allowed here.");
}
return ConstantPointerRef::get(GV);
}
default:
throw std::string("Don't know how to deserialize constant value of type '"+
Ty->getDescription());
}
}
void BytecodeParser::ParseGlobalTypes(const unsigned char *&Buf,
const unsigned char *EndBuf) {
ValueTable T;
ParseConstantPool(Buf, EndBuf, T, ModuleTypeValues);
}
void BytecodeParser::parseStringConstants(const unsigned char *&Buf,
const unsigned char *EndBuf,
unsigned NumEntries, ValueTable &Tab){
for (; NumEntries; --NumEntries) {
unsigned Typ = read_vbr_uint(Buf, EndBuf);
const Type *Ty = getType(Typ);
if (!isa<ArrayType>(Ty))
throw std::string("String constant data invalid!");
const ArrayType *ATy = cast<ArrayType>(Ty);
if (ATy->getElementType() != Type::SByteTy &&
ATy->getElementType() != Type::UByteTy)
throw std::string("String constant data invalid!");
// Read character data. The type tells us how long the string is.
char Data[ATy->getNumElements()];
input_data(Buf, EndBuf, Data, Data+ATy->getNumElements());
std::vector<Constant*> Elements(ATy->getNumElements());
if (ATy->getElementType() == Type::SByteTy)
for (unsigned i = 0, e = ATy->getNumElements(); i != e; ++i)
Elements[i] = ConstantSInt::get(Type::SByteTy, (signed char)Data[i]);
else
for (unsigned i = 0, e = ATy->getNumElements(); i != e; ++i)
Elements[i] = ConstantUInt::get(Type::UByteTy, (unsigned char)Data[i]);
// Create the constant, inserting it as needed.
Constant *C = ConstantArray::get(ATy, Elements);
unsigned Slot = insertValue(C, Typ, Tab);
ResolveReferencesToConstant(C, Slot);
}
}
void BytecodeParser::ParseConstantPool(const unsigned char *&Buf,
const unsigned char *EndBuf,
ValueTable &Tab,
TypeValuesListTy &TypeTab) {
while (Buf < EndBuf) {
unsigned NumEntries = read_vbr_uint(Buf, EndBuf);
unsigned Typ = read_vbr_uint(Buf, EndBuf);
if (Typ == Type::TypeTyID) {
BCR_TRACE(3, "Type: 'type' NumEntries: " << NumEntries << "\n");
parseTypeConstants(Buf, EndBuf, TypeTab, NumEntries);
} else if (Typ == Type::VoidTyID) {
assert(&Tab == &ModuleValues && "Cannot read strings in functions!");
parseStringConstants(Buf, EndBuf, NumEntries, Tab);
} else {
BCR_TRACE(3, "Type: '" << *getType(Typ) << "' NumEntries: "
<< NumEntries << "\n");
for (unsigned i = 0; i < NumEntries; ++i) {
Constant *C = parseConstantValue(Buf, EndBuf, Typ);
assert(C && "parseConstantValue returned NULL!");
BCR_TRACE(4, "Read Constant: '" << *C << "'\n");
unsigned Slot = insertValue(C, Typ, Tab);
// If we are reading a function constant table, make sure that we adjust
// the slot number to be the real global constant number.
//
if (&Tab != &ModuleValues && Typ < ModuleValues.size() &&
ModuleValues[Typ])
Slot += ModuleValues[Typ]->size();
ResolveReferencesToConstant(C, Slot);
}
}
}
if (Buf > EndBuf) throw std::string("Read past end of buffer.");
}