llvm-6502/lib/Bytecode/Reader/ConstantReader.cpp
Chris Lattner bbd4b303e3 There is no way to guarantee that constants are not forward referenced.
Handle forward referenced constants in a general way.  This fixes bug:
Assembler/2002-10-13-ConstantEncodingProblem.llx and allows the SPEC
197.parser benchmark to be built


git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@4161 91177308-0d34-0410-b5e6-96231b3b80d8
2002-10-14 03:33:02 +00:00

417 lines
13 KiB
C++

//===- ReadConst.cpp - Code to constants and constant pools ---------------===//
//
// This file implements functionality to deserialize constants and entire
// constant pools.
//
// Note that this library should be as fast as possible, reentrant, and
// threadsafe!!
//
//===----------------------------------------------------------------------===//
#include "ReaderInternals.h"
#include "llvm/Module.h"
#include "llvm/Constants.h"
#include <algorithm>
using std::make_pair;
const Type *BytecodeParser::parseTypeConstant(const uchar *&Buf,
const uchar *EndBuf) {
unsigned PrimType;
if (read_vbr(Buf, EndBuf, PrimType)) return 0;
const Type *Val = 0;
if ((Val = Type::getPrimitiveType((Type::PrimitiveID)PrimType)))
return Val;
switch (PrimType) {
case Type::FunctionTyID: {
unsigned Typ;
if (read_vbr(Buf, EndBuf, Typ)) return Val;
const Type *RetType = getType(Typ);
if (RetType == 0) return Val;
unsigned NumParams;
if (read_vbr(Buf, EndBuf, NumParams)) return Val;
std::vector<const Type*> Params;
while (NumParams--) {
if (read_vbr(Buf, EndBuf, Typ)) return Val;
const Type *Ty = getType(Typ);
if (Ty == 0) return Val;
Params.push_back(Ty);
}
bool isVarArg = Params.size() && Params.back() == Type::VoidTy;
if (isVarArg) Params.pop_back();
return FunctionType::get(RetType, Params, isVarArg);
}
case Type::ArrayTyID: {
unsigned ElTyp;
if (read_vbr(Buf, EndBuf, ElTyp)) return Val;
const Type *ElementType = getType(ElTyp);
if (ElementType == 0) return Val;
unsigned NumElements;
if (read_vbr(Buf, EndBuf, NumElements)) return Val;
BCR_TRACE(5, "Array Type Constant #" << ElTyp << " size="
<< NumElements << "\n");
return ArrayType::get(ElementType, NumElements);
}
case Type::StructTyID: {
unsigned Typ;
std::vector<const Type*> Elements;
if (read_vbr(Buf, EndBuf, Typ)) return Val;
while (Typ) { // List is terminated by void/0 typeid
const Type *Ty = getType(Typ);
if (Ty == 0) return Val;
Elements.push_back(Ty);
if (read_vbr(Buf, EndBuf, Typ)) return Val;
}
return StructType::get(Elements);
}
case Type::PointerTyID: {
unsigned ElTyp;
if (read_vbr(Buf, EndBuf, ElTyp)) return Val;
BCR_TRACE(5, "Pointer Type Constant #" << (ElTyp-14) << "\n");
const Type *ElementType = getType(ElTyp);
if (ElementType == 0) return Val;
return PointerType::get(ElementType);
}
case Type::OpaqueTyID: {
return OpaqueType::get();
}
default:
std::cerr << __FILE__ << ":" << __LINE__
<< ": Don't know how to deserialize"
<< " primitive Type " << PrimType << "\n";
return Val;
}
}
// refineAbstractType - The callback method is invoked when one of the
// elements of TypeValues becomes more concrete...
//
void BytecodeParser::refineAbstractType(const DerivedType *OldType,
const Type *NewType) {
if (OldType == NewType &&
OldType->isAbstract()) return; // Type is modified, but same
TypeValuesListTy::iterator I = find(MethodTypeValues.begin(),
MethodTypeValues.end(), OldType);
if (I == MethodTypeValues.end()) {
I = find(ModuleTypeValues.begin(), ModuleTypeValues.end(), OldType);
assert(I != ModuleTypeValues.end() &&
"Can't refine a type I don't know about!");
}
if (OldType == NewType) {
assert(!OldType->isAbstract());
I->removeUserFromConcrete();
} else {
*I = NewType; // Update to point to new, more refined type.
}
}
// parseTypeConstants - We have to use this wierd 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 pesimistically 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 debug_type_tables();
bool BytecodeParser::parseTypeConstants(const uchar *&Buf, const uchar *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...
for (unsigned i = 0; i < NumEntries; ++i)
Tab.push_back(PATypeHandle<Type>(OpaqueType::get(), this));
// 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) return true;
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 the newty. This also will cause the opaque type
// to be deleted...
//
((DerivedType*)Tab[i].get())->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");
}
debug_type_tables();
return false;
}
bool BytecodeParser::parseConstantValue(const uchar *&Buf, const uchar *EndBuf,
const Type *Ty, Constant *&V) {
// We must check for a ConstantExpr before switching by type because
// a ConstantExpr can be of any type, and has no explicit value.
//
unsigned isExprNumArgs; // 0 if not expr; numArgs if is expr
if (read_vbr(Buf, EndBuf, isExprNumArgs)) return true;
if (isExprNumArgs) {
// FIXME: Encoding of constant exprs could be much more compact!
unsigned Opcode;
std::vector<Constant*> ArgVec;
ArgVec.reserve(isExprNumArgs);
if (read_vbr(Buf, EndBuf, Opcode)) return true;
// Read the slot number and types of each of the arguments
for (unsigned i = 0; i != isExprNumArgs; ++i) {
unsigned ArgValSlot, ArgTypeSlot;
if (read_vbr(Buf, EndBuf, ArgValSlot)) return true;
if (read_vbr(Buf, EndBuf, ArgTypeSlot)) return true;
const Type *ArgTy = getType(ArgTypeSlot);
if (ArgTy == 0) return true;
BCR_TRACE(4, "CE Arg " << i << ": Type: '" << ArgTy << "' slot: "
<< ArgValSlot << "\n");
// Get the arg value from its slot if it exists, otherwise a placeholder
Constant *C = getConstantValue(ArgTy, ArgValSlot);
if (C == 0) return true;
ArgVec.push_back(C);
}
// Construct a ConstantExpr of the appropriate kind
if (isExprNumArgs == 1) { // All one-operand expressions
assert(Opcode == Instruction::Cast);
V = ConstantExpr::getCast(ArgVec[0], Ty);
} else if (Opcode == Instruction::GetElementPtr) { // GetElementPtr
std::vector<Constant*> IdxList(ArgVec.begin()+1, ArgVec.end());
V = ConstantExpr::getGetElementPtr(ArgVec[0], IdxList);
} else { // All other 2-operand expressions
V = ConstantExpr::get(Opcode, ArgVec[0], ArgVec[1]);
}
return false;
}
// Ok, not an ConstantExpr. We now know how to read the given type...
switch (Ty->getPrimitiveID()) {
case Type::BoolTyID: {
unsigned Val;
if (read_vbr(Buf, EndBuf, Val)) return true;
if (Val != 0 && Val != 1) return true;
V = ConstantBool::get(Val == 1);
break;
}
case Type::UByteTyID: // Unsigned integer types...
case Type::UShortTyID:
case Type::UIntTyID: {
unsigned Val;
if (read_vbr(Buf, EndBuf, Val)) return true;
if (!ConstantUInt::isValueValidForType(Ty, Val)) return true;
V = ConstantUInt::get(Ty, Val);
break;
}
case Type::ULongTyID: {
uint64_t Val;
if (read_vbr(Buf, EndBuf, Val)) return true;
V = ConstantUInt::get(Ty, Val);
break;
}
case Type::SByteTyID: // Unsigned integer types...
case Type::ShortTyID:
case Type::IntTyID: {
int Val;
if (read_vbr(Buf, EndBuf, Val)) return true;
if (!ConstantSInt::isValueValidForType(Ty, Val)) return true;
V = ConstantSInt::get(Ty, Val);
break;
}
case Type::LongTyID: {
int64_t Val;
if (read_vbr(Buf, EndBuf, Val)) return true;
V = ConstantSInt::get(Ty, Val);
break;
}
case Type::FloatTyID: {
float F;
if (input_data(Buf, EndBuf, &F, &F+1)) return true;
V = ConstantFP::get(Ty, F);
break;
}
case Type::DoubleTyID: {
double Val;
if (input_data(Buf, EndBuf, &Val, &Val+1)) return true;
V = ConstantFP::get(Ty, Val);
break;
}
case Type::TypeTyID:
assert(0 && "Type constants should be handled seperately!!!");
abort();
case Type::ArrayTyID: {
const ArrayType *AT = cast<const ArrayType>(Ty);
unsigned NumElements = AT->getNumElements();
std::vector<Constant*> Elements;
while (NumElements--) { // Read all of the elements of the constant.
unsigned Slot;
if (read_vbr(Buf, EndBuf, Slot)) return true;
Constant *C = getConstantValue(AT->getElementType(), Slot);
if (!C) return true;
Elements.push_back(C);
}
V = ConstantArray::get(AT, Elements);
break;
}
case Type::StructTyID: {
const StructType *ST = cast<StructType>(Ty);
const StructType::ElementTypes &ET = ST->getElementTypes();
std::vector<Constant *> Elements;
for (unsigned i = 0; i < ET.size(); ++i) {
unsigned Slot;
if (read_vbr(Buf, EndBuf, Slot)) return true;
Constant *C = getConstantValue(ET[i], Slot);
if (!C) return true;
Elements.push_back(C);
}
V = ConstantStruct::get(ST, Elements);
break;
}
case Type::PointerTyID: {
const PointerType *PT = cast<const PointerType>(Ty);
unsigned SubClass;
if (read_vbr(Buf, EndBuf, SubClass)) return true;
switch (SubClass) {
case 0: // ConstantPointerNull value...
V = ConstantPointerNull::get(PT);
break;
case 1: { // ConstantPointerRef value...
unsigned Slot;
if (read_vbr(Buf, EndBuf, Slot)) return true;
BCR_TRACE(4, "CPR: Type: '" << Ty << "' slot: " << Slot << "\n");
// Check to see if we have already read this global variable...
Value *Val = getValue(PT, Slot, false);
GlobalValue *GV;
if (Val) {
if (!(GV = dyn_cast<GlobalValue>(Val))) return true;
BCR_TRACE(5, "Value Found in ValueTable!\n");
} else { // Nope... find or create a forward ref. for it
GlobalRefsType::iterator I = GlobalRefs.find(make_pair(PT, Slot));
if (I != GlobalRefs.end()) {
BCR_TRACE(5, "Previous forward ref found!\n");
GV = cast<GlobalValue>(I->second);
} else {
BCR_TRACE(5, "Creating new forward ref to a global variable!\n");
// Create a placeholder for the global variable reference...
GlobalVariable *GVar =
new GlobalVariable(PT->getElementType(), false, true);
// Keep track of the fact that we have a forward ref to recycle it
GlobalRefs.insert(make_pair(make_pair(PT, Slot), GVar));
// Must temporarily push this value into the module table...
TheModule->getGlobalList().push_back(GVar);
GV = GVar;
}
}
V = ConstantPointerRef::get(GV);
break;
}
default:
BCR_TRACE(5, "UNKNOWN Pointer Constant Type!\n");
return true;
}
break;
}
default:
std::cerr << __FILE__ << ":" << __LINE__
<< ": Don't know how to deserialize constant value of type '"
<< Ty->getName() << "'\n";
return true;
}
return false;
}
bool BytecodeParser::ParseConstantPool(const uchar *&Buf, const uchar *EndBuf,
ValueTable &Tab,
TypeValuesListTy &TypeTab) {
while (Buf < EndBuf) {
unsigned NumEntries, Typ;
if (read_vbr(Buf, EndBuf, NumEntries) ||
read_vbr(Buf, EndBuf, Typ)) return true;
const Type *Ty = getType(Typ);
if (Ty == 0) return true;
BCR_TRACE(3, "Type: '" << Ty << "' NumEntries: " << NumEntries << "\n");
if (Typ == Type::TypeTyID) {
if (parseTypeConstants(Buf, EndBuf, TypeTab, NumEntries)) return true;
} else {
for (unsigned i = 0; i < NumEntries; ++i) {
Constant *I;
int Slot;
if (parseConstantValue(Buf, EndBuf, Ty, I)) return true;
assert(I && "parseConstantValue returned NULL!");
BCR_TRACE(4, "Read Constant: '" << I << "'\n");
if ((Slot = insertValue(I, Tab)) < 0) return true;
// 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)
Slot += ModuleValues[Typ].size();
ResolveReferencesToValue(I, (unsigned)Slot);
}
}
}
if (Buf > EndBuf) return true;
return false;
}