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llvm-mirror/lib/Bytecode/Reader/Reader.cpp
Chris Lattner 874db50b32 Make error message a bit nicer. 
Contributed by Reid Spencer

llvm-svn: 12523
2004-03-29 00:16:01 +00:00

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//===- Reader.cpp - Code to read bytecode files ---------------------------===//
//
// 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 library implements the functionality defined in llvm/Bytecode/Reader.h
//
// Note that this library should be as fast as possible, reentrant, and
// threadsafe!!
//
// TODO: Allow passing in an option to ignore the symbol table
//
//===----------------------------------------------------------------------===//
#include "ReaderInternals.h"
#include "llvm/Bytecode/Reader.h"
#include "llvm/Bytecode/Format.h"
#include "llvm/Module.h"
#include "Support/StringExtras.h"
using namespace llvm;
unsigned BytecodeParser::getTypeSlot(const Type *Ty) {
if (Ty->isPrimitiveType())
return Ty->getPrimitiveID();
// Scan the compaction table for the type if needed.
if (CompactionTable.size() > Type::TypeTyID) {
std::vector<Value*> &Plane = CompactionTable[Type::TypeTyID];
if (!Plane.empty()) {
std::vector<Value*>::iterator I = find(Plane.begin(), Plane.end(),
const_cast<Type*>(Ty));
if (I == Plane.end())
throw std::string("Couldn't find type specified in compaction table!");
return Type::FirstDerivedTyID + (&*I - &Plane[0]);
}
}
// Check the function level types first...
TypeValuesListTy::iterator I = find(FunctionTypeValues.begin(),
FunctionTypeValues.end(), Ty);
if (I != FunctionTypeValues.end())
return Type::FirstDerivedTyID + ModuleTypeValues.size() +
(&*I - &FunctionTypeValues[0]);
I = find(ModuleTypeValues.begin(), ModuleTypeValues.end(), Ty);
if (I == ModuleTypeValues.end())
throw std::string("Didn't find type in ModuleTypeValues.");
return Type::FirstDerivedTyID + (&*I - &ModuleTypeValues[0]);
}
const Type *BytecodeParser::getType(unsigned ID) {
//cerr << "Looking up Type ID: " << ID << "\n";
if (ID < Type::FirstDerivedTyID)
if (const Type *T = Type::getPrimitiveType((Type::PrimitiveID)ID))
return T; // Asked for a primitive type...
// Otherwise, derived types need offset...
ID -= Type::FirstDerivedTyID;
if (CompactionTable.size() > Type::TypeTyID &&
!CompactionTable[Type::TypeTyID].empty()) {
if (ID >= CompactionTable[Type::TypeTyID].size())
throw std::string("Type ID out of range for compaction table!");
return cast<Type>(CompactionTable[Type::TypeTyID][ID]);
}
// Is it a module-level type?
if (ID < ModuleTypeValues.size())
return ModuleTypeValues[ID].get();
// Nope, is it a function-level type?
ID -= ModuleTypeValues.size();
if (ID < FunctionTypeValues.size())
return FunctionTypeValues[ID].get();
throw std::string("Illegal type reference!");
}
static inline bool hasImplicitNull(unsigned TyID, bool EncodesPrimitiveZeros) {
if (!EncodesPrimitiveZeros)
return TyID != Type::LabelTyID && TyID != Type::TypeTyID &&
TyID != Type::VoidTyID;
return TyID >= Type::FirstDerivedTyID;
}
unsigned BytecodeParser::insertValue(Value *Val, unsigned type,
ValueTable &ValueTab) {
assert((!isa<Constant>(Val) || !cast<Constant>(Val)->isNullValue()) ||
!hasImplicitNull(type, hasExplicitPrimitiveZeros) &&
"Cannot read null values from bytecode!");
assert(type != Type::TypeTyID && "Types should never be insertValue'd!");
if (ValueTab.size() <= type)
ValueTab.resize(type+1);
if (!ValueTab[type]) ValueTab[type] = new ValueList();
//cerr << "insertValue Values[" << type << "][" << ValueTab[type].size()
// << "] = " << Val << "\n";
ValueTab[type]->push_back(Val);
bool HasOffset = hasImplicitNull(type, hasExplicitPrimitiveZeros);
return ValueTab[type]->size()-1 + HasOffset;
}
Value *BytecodeParser::getValue(unsigned type, unsigned oNum, bool Create) {
assert(type != Type::TypeTyID && "getValue() cannot get types!");
assert(type != Type::LabelTyID && "getValue() cannot get blocks!");
unsigned Num = oNum;
// If there is a compaction table active, it defines the low-level numbers.
// If not, the module values define the low-level numbers.
if (CompactionTable.size() > type && !CompactionTable[type].empty()) {
if (Num < CompactionTable[type].size())
return CompactionTable[type][Num];
Num -= CompactionTable[type].size();
} else {
// If the type plane was compactified, figure out the global type ID.
unsigned GlobalTyID = type;
if (CompactionTable.size() > Type::TypeTyID &&
!CompactionTable[Type::TypeTyID].empty() &&
type >= Type::FirstDerivedTyID) {
std::vector<Value*> &TypePlane = CompactionTable[Type::TypeTyID];
const Type *Ty = cast<Type>(TypePlane[type-Type::FirstDerivedTyID]);
TypeValuesListTy::iterator I =
find(ModuleTypeValues.begin(), ModuleTypeValues.end(), Ty);
assert(I != ModuleTypeValues.end());
GlobalTyID = Type::FirstDerivedTyID + (&*I - &ModuleTypeValues[0]);
}
if (hasImplicitNull(GlobalTyID, hasExplicitPrimitiveZeros)) {
if (Num == 0)
return Constant::getNullValue(getType(type));
--Num;
}
if (GlobalTyID < ModuleValues.size() && ModuleValues[GlobalTyID]) {
if (Num < ModuleValues[GlobalTyID]->size())
return ModuleValues[GlobalTyID]->getOperand(Num);
Num -= ModuleValues[GlobalTyID]->size();
}
}
if (Values.size() > type && Values[type] && Num < Values[type]->size())
return Values[type]->getOperand(Num);
if (!Create) return 0; // Do not create a placeholder?
std::pair<unsigned,unsigned> KeyValue(type, oNum);
std::map<std::pair<unsigned,unsigned>, Value*>::iterator I =
ForwardReferences.lower_bound(KeyValue);
if (I != ForwardReferences.end() && I->first == KeyValue)
return I->second; // We have already created this placeholder
Value *Val = new Argument(getType(type));
ForwardReferences.insert(I, std::make_pair(KeyValue, Val));
return Val;
}
/// getBasicBlock - Get a particular numbered basic block, which might be a
/// forward reference. This works together with ParseBasicBlock to handle these
/// forward references in a clean manner.
///
BasicBlock *BytecodeParser::getBasicBlock(unsigned ID) {
// Make sure there is room in the table...
if (ParsedBasicBlocks.size() <= ID) ParsedBasicBlocks.resize(ID+1);
// First check to see if this is a backwards reference, i.e., ParseBasicBlock
// has already created this block, or if the forward reference has already
// been created.
if (ParsedBasicBlocks[ID])
return ParsedBasicBlocks[ID];
// Otherwise, the basic block has not yet been created. Do so and add it to
// the ParsedBasicBlocks list.
return ParsedBasicBlocks[ID] = new BasicBlock();
}
/// getConstantValue - Just like getValue, except that it returns a null pointer
/// only on error. It always returns a constant (meaning that if the value is
/// defined, but is not a constant, that is an error). If the specified
/// constant hasn't been parsed yet, a placeholder is defined and used. Later,
/// after the real value is parsed, the placeholder is eliminated.
///
Constant *BytecodeParser::getConstantValue(unsigned TypeSlot, unsigned Slot) {
if (Value *V = getValue(TypeSlot, Slot, false))
if (Constant *C = dyn_cast<Constant>(V))
return C; // If we already have the value parsed, just return it
else if (GlobalValue *GV = dyn_cast<GlobalValue>(V))
// ConstantPointerRef's are an abomination, but at least they don't have
// to infest bytecode files.
return ConstantPointerRef::get(GV);
else
throw std::string("Reference of a value is expected to be a constant!");
const Type *Ty = getType(TypeSlot);
std::pair<const Type*, unsigned> Key(Ty, Slot);
ConstantRefsType::iterator I = ConstantFwdRefs.lower_bound(Key);
if (I != ConstantFwdRefs.end() && I->first == Key) {
BCR_TRACE(5, "Previous forward ref found!\n");
return I->second;
} else {
// Create a placeholder for the constant reference and
// keep track of the fact that we have a forward ref to recycle it
BCR_TRACE(5, "Creating new forward ref to a constant!\n");
Constant *C = new ConstPHolder(Ty, Slot);
// Keep track of the fact that we have a forward ref to recycle it
ConstantFwdRefs.insert(I, std::make_pair(Key, C));
return C;
}
}
/// ParseBasicBlock - In LLVM 1.0 bytecode files, we used to output one
/// basicblock at a time. This method reads in one of the basicblock packets.
BasicBlock *BytecodeParser::ParseBasicBlock(const unsigned char *&Buf,
const unsigned char *EndBuf,
unsigned BlockNo) {
BasicBlock *BB;
if (ParsedBasicBlocks.size() == BlockNo)
ParsedBasicBlocks.push_back(BB = new BasicBlock());
else if (ParsedBasicBlocks[BlockNo] == 0)
BB = ParsedBasicBlocks[BlockNo] = new BasicBlock();
else
BB = ParsedBasicBlocks[BlockNo];
std::vector<unsigned> Args;
while (Buf < EndBuf)
ParseInstruction(Buf, EndBuf, Args, BB);
return BB;
}
/// ParseInstructionList - Parse all of the BasicBlock's & Instruction's in the
/// body of a function. In post 1.0 bytecode files, we no longer emit basic
/// block individually, in order to avoid per-basic-block overhead.
unsigned BytecodeParser::ParseInstructionList(Function *F,
const unsigned char *&Buf,
const unsigned char *EndBuf) {
unsigned BlockNo = 0;
std::vector<unsigned> Args;
while (Buf < EndBuf) {
BasicBlock *BB;
if (ParsedBasicBlocks.size() == BlockNo)
ParsedBasicBlocks.push_back(BB = new BasicBlock());
else if (ParsedBasicBlocks[BlockNo] == 0)
BB = ParsedBasicBlocks[BlockNo] = new BasicBlock();
else
BB = ParsedBasicBlocks[BlockNo];
++BlockNo;
F->getBasicBlockList().push_back(BB);
// Read instructions into this basic block until we get to a terminator
while (Buf < EndBuf && !BB->getTerminator())
ParseInstruction(Buf, EndBuf, Args, BB);
if (!BB->getTerminator())
throw std::string("Non-terminated basic block found!");
}
return BlockNo;
}
void BytecodeParser::ParseSymbolTable(const unsigned char *&Buf,
const unsigned char *EndBuf,
SymbolTable *ST,
Function *CurrentFunction) {
// Allow efficient basic block lookup by number.
std::vector<BasicBlock*> BBMap;
if (CurrentFunction)
for (Function::iterator I = CurrentFunction->begin(),
E = CurrentFunction->end(); I != E; ++I)
BBMap.push_back(I);
while (Buf < EndBuf) {
// Symtab block header: [num entries][type id number]
unsigned NumEntries = read_vbr_uint(Buf, EndBuf);
unsigned Typ = read_vbr_uint(Buf, EndBuf);
const Type *Ty = getType(Typ);
BCR_TRACE(3, "Plane Type: '" << *Ty << "' with " << NumEntries <<
" entries\n");
for (unsigned i = 0; i != NumEntries; ++i) {
// Symtab entry: [def slot #][name]
unsigned slot = read_vbr_uint(Buf, EndBuf);
std::string Name = read_str(Buf, EndBuf);
Value *V = 0;
if (Typ == Type::TypeTyID)
V = (Value*)getType(slot);
else if (Typ == Type::LabelTyID) {
if (slot < BBMap.size())
V = BBMap[slot];
} else {
V = getValue(Typ, slot, false); // Find mapping...
}
if (V == 0)
throw "Failed value look-up for name '" + Name + "'";
BCR_TRACE(4, "Map: '" << Name << "' to #" << slot << ":" << *V;
if (!isa<Instruction>(V)) std::cerr << "\n");
V->setName(Name, ST);
}
}
if (Buf > EndBuf) throw std::string("Tried to read past end of buffer.");
}
void BytecodeParser::ResolveReferencesToConstant(Constant *NewV, unsigned Slot){
ConstantRefsType::iterator I =
ConstantFwdRefs.find(std::make_pair(NewV->getType(), Slot));
if (I == ConstantFwdRefs.end()) return; // Never forward referenced?
BCR_TRACE(3, "Mutating forward refs!\n");
Value *PH = I->second; // Get the placeholder...
PH->replaceAllUsesWith(NewV);
delete PH; // Delete the old placeholder
ConstantFwdRefs.erase(I); // Remove the map entry for it
}
void BytecodeParser::ParseFunction(const unsigned char *&Buf,
const unsigned char *EndBuf) {
if (FunctionSignatureList.empty())
throw std::string("FunctionSignatureList empty!");
Function *F = FunctionSignatureList.back();
FunctionSignatureList.pop_back();
// Save the information for future reading of the function
LazyFunctionLoadMap[F] = LazyFunctionInfo(Buf, EndBuf);
// Pretend we've `parsed' this function
Buf = EndBuf;
}
void BytecodeParser::materializeFunction(Function* F) {
// Find {start, end} pointers and slot in the map. If not there, we're done.
std::map<Function*, LazyFunctionInfo>::iterator Fi =
LazyFunctionLoadMap.find(F);
if (Fi == LazyFunctionLoadMap.end()) return;
const unsigned char *Buf = Fi->second.Buf;
const unsigned char *EndBuf = Fi->second.EndBuf;
LazyFunctionLoadMap.erase(Fi);
GlobalValue::LinkageTypes Linkage = GlobalValue::ExternalLinkage;
unsigned LinkageType = read_vbr_uint(Buf, EndBuf);
if ((!hasExtendedLinkageSpecs && LinkageType > 3) ||
( hasExtendedLinkageSpecs && LinkageType > 4))
throw std::string("Invalid linkage type for Function.");
switch (LinkageType) {
case 0: Linkage = GlobalValue::ExternalLinkage; break;
case 1: Linkage = GlobalValue::WeakLinkage; break;
case 2: Linkage = GlobalValue::AppendingLinkage; break;
case 3: Linkage = GlobalValue::InternalLinkage; break;
case 4: Linkage = GlobalValue::LinkOnceLinkage; break;
}
F->setLinkage(Linkage);
// Keep track of how many basic blocks we have read in...
unsigned BlockNum = 0;
bool InsertedArguments = false;
while (Buf < EndBuf) {
unsigned Type, Size;
const unsigned char *OldBuf = Buf;
readBlock(Buf, EndBuf, Type, Size);
switch (Type) {
case BytecodeFormat::ConstantPool:
if (!InsertedArguments) {
// Insert arguments into the value table before we parse the first basic
// block in the function, but after we potentially read in the
// compaction table.
const FunctionType *FT = F->getFunctionType();
Function::aiterator AI = F->abegin();
for (FunctionType::param_iterator It = FT->param_begin();
It != FT->param_end(); ++It, ++AI)
insertValue(AI, getTypeSlot(AI->getType()), Values);
InsertedArguments = true;
}
BCR_TRACE(2, "BLOCK BytecodeFormat::ConstantPool: {\n");
ParseConstantPool(Buf, Buf+Size, Values, FunctionTypeValues);
break;
case BytecodeFormat::CompactionTable:
BCR_TRACE(2, "BLOCK BytecodeFormat::CompactionTable: {\n");
ParseCompactionTable(Buf, Buf+Size);
break;
case BytecodeFormat::BasicBlock: {
if (!InsertedArguments) {
// Insert arguments into the value table before we parse the first basic
// block in the function, but after we potentially read in the
// compaction table.
const FunctionType *FT = F->getFunctionType();
Function::aiterator AI = F->abegin();
for (FunctionType::param_iterator It = FT->param_begin();
It != FT->param_end(); ++It, ++AI)
insertValue(AI, getTypeSlot(AI->getType()), Values);
InsertedArguments = true;
}
BCR_TRACE(2, "BLOCK BytecodeFormat::BasicBlock: {\n");
BasicBlock *BB = ParseBasicBlock(Buf, Buf+Size, BlockNum++);
F->getBasicBlockList().push_back(BB);
break;
}
case BytecodeFormat::InstructionList: {
// Insert arguments into the value table before we parse the instruction
// list for the function, but after we potentially read in the compaction
// table.
if (!InsertedArguments) {
const FunctionType *FT = F->getFunctionType();
Function::aiterator AI = F->abegin();
for (FunctionType::param_iterator It = FT->param_begin();
It != FT->param_end(); ++It, ++AI)
insertValue(AI, getTypeSlot(AI->getType()), Values);
InsertedArguments = true;
}
BCR_TRACE(2, "BLOCK BytecodeFormat::InstructionList: {\n");
if (BlockNum) throw std::string("Already parsed basic blocks!");
BlockNum = ParseInstructionList(F, Buf, Buf+Size);
break;
}
case BytecodeFormat::SymbolTable:
BCR_TRACE(2, "BLOCK BytecodeFormat::SymbolTable: {\n");
ParseSymbolTable(Buf, Buf+Size, &F->getSymbolTable(), F);
break;
default:
BCR_TRACE(2, "BLOCK <unknown>:ignored! {\n");
Buf += Size;
if (OldBuf > Buf)
throw std::string("Wrapped around reading bytecode.");
break;
}
BCR_TRACE(2, "} end block\n");
// Malformed bc file if read past end of block.
align32(Buf, EndBuf);
}
// Make sure there were no references to non-existant basic blocks.
if (BlockNum != ParsedBasicBlocks.size())
throw std::string("Illegal basic block operand reference");
ParsedBasicBlocks.clear();
// Resolve forward references. Replace any uses of a forward reference value
// with the real value.
// replaceAllUsesWith is very inefficient for instructions which have a LARGE
// number of operands. PHI nodes often have forward references, and can also
// often have a very large number of operands.
//
// FIXME: REEVALUATE. replaceAllUsesWith is _much_ faster now, and this code
// should be simplified back to using it!
//
std::map<Value*, Value*> ForwardRefMapping;
for (std::map<std::pair<unsigned,unsigned>, Value*>::iterator
I = ForwardReferences.begin(), E = ForwardReferences.end();
I != E; ++I)
ForwardRefMapping[I->second] = getValue(I->first.first, I->first.second,
false);
for (Function::iterator BB = F->begin(), E = F->end(); BB != E; ++BB)
for (BasicBlock::iterator I = BB->begin(), E = BB->end(); I != E; ++I)
for (unsigned i = 0, e = I->getNumOperands(); i != e; ++i)
if (Argument *A = dyn_cast<Argument>(I->getOperand(i))) {
std::map<Value*, Value*>::iterator It = ForwardRefMapping.find(A);
if (It != ForwardRefMapping.end()) I->setOperand(i, It->second);
}
while (!ForwardReferences.empty()) {
std::map<std::pair<unsigned,unsigned>, Value*>::iterator I =
ForwardReferences.begin();
Value *PlaceHolder = I->second;
ForwardReferences.erase(I);
// Now that all the uses are gone, delete the placeholder...
// If we couldn't find a def (error case), then leak a little
// memory, because otherwise we can't remove all uses!
delete PlaceHolder;
}
// Clear out function-level types...
FunctionTypeValues.clear();
CompactionTable.clear();
freeTable(Values);
}
void BytecodeParser::ParseCompactionTable(const unsigned char *&Buf,
const unsigned char *End) {
while (Buf != End) {
unsigned NumEntries = read_vbr_uint(Buf, End);
unsigned Ty;
if ((NumEntries & 3) == 3) {
NumEntries >>= 2;
Ty = read_vbr_uint(Buf, End);
} else {
Ty = NumEntries >> 2;
NumEntries &= 3;
}
if (Ty >= CompactionTable.size())
CompactionTable.resize(Ty+1);
if (!CompactionTable[Ty].empty())
throw std::string("Compaction table plane contains multiple entries!");
if (Ty == Type::TypeTyID) {
for (unsigned i = 0; i != NumEntries; ++i) {
const Type *Typ = getGlobalTableType(read_vbr_uint(Buf, End));
CompactionTable[Type::TypeTyID].push_back(const_cast<Type*>(Typ));
}
CompactionTable.resize(NumEntries+Type::FirstDerivedTyID);
} else {
const Type *Typ = getType(Ty);
// Push the implicit zero
CompactionTable[Ty].push_back(Constant::getNullValue(Typ));
for (unsigned i = 0; i != NumEntries; ++i) {
Value *V = getGlobalTableValue(Typ, read_vbr_uint(Buf, End));
CompactionTable[Ty].push_back(V);
}
}
}
}
void BytecodeParser::ParseModuleGlobalInfo(const unsigned char *&Buf,
const unsigned char *End) {
if (!FunctionSignatureList.empty())
throw std::string("Two ModuleGlobalInfo packets found!");
// Read global variables...
unsigned VarType = read_vbr_uint(Buf, End);
while (VarType != Type::VoidTyID) { // List is terminated by Void
unsigned SlotNo;
GlobalValue::LinkageTypes Linkage;
unsigned LinkageID;
if (hasExtendedLinkageSpecs) {
// VarType Fields: bit0 = isConstant, bit1 = hasInitializer,
// bit2,3,4 = Linkage, bit4+ = slot#
SlotNo = VarType >> 5;
LinkageID = (VarType >> 2) & 7;
} else {
// VarType Fields: bit0 = isConstant, bit1 = hasInitializer,
// bit2,3 = Linkage, bit4+ = slot#
SlotNo = VarType >> 4;
LinkageID = (VarType >> 2) & 3;
}
switch (LinkageID) {
default: assert(0 && "Unknown linkage type!");
case 0: Linkage = GlobalValue::ExternalLinkage; break;
case 1: Linkage = GlobalValue::WeakLinkage; break;
case 2: Linkage = GlobalValue::AppendingLinkage; break;
case 3: Linkage = GlobalValue::InternalLinkage; break;
case 4: Linkage = GlobalValue::LinkOnceLinkage; break;
}
const Type *Ty = getType(SlotNo);
if (!isa<PointerType>(Ty))
throw std::string("Global not pointer type! Ty = " +
Ty->getDescription());
const Type *ElTy = cast<PointerType>(Ty)->getElementType();
// Create the global variable...
GlobalVariable *GV = new GlobalVariable(ElTy, VarType & 1, Linkage,
0, "", TheModule);
BCR_TRACE(2, "Global Variable of type: " << *Ty << "\n");
insertValue(GV, SlotNo, ModuleValues);
if (VarType & 2) // Does it have an initializer?
GlobalInits.push_back(std::make_pair(GV, read_vbr_uint(Buf, End)));
VarType = read_vbr_uint(Buf, End);
}
// Read the function objects for all of the functions that are coming
unsigned FnSignature = read_vbr_uint(Buf, End);
while (FnSignature != Type::VoidTyID) { // List is terminated by Void
const Type *Ty = getType(FnSignature);
if (!isa<PointerType>(Ty) ||
!isa<FunctionType>(cast<PointerType>(Ty)->getElementType()))
throw std::string("Function not ptr to func type! Ty = " +
Ty->getDescription());
// We create functions by passing the underlying FunctionType to create...
Ty = cast<PointerType>(Ty)->getElementType();
// When the ModuleGlobalInfo section is read, we load the type of each
// function and the 'ModuleValues' slot that it lands in. We then load a
// placeholder into its slot to reserve it. When the function is loaded,
// this placeholder is replaced.
// Insert the placeholder...
Function *Func = new Function(cast<FunctionType>(Ty),
GlobalValue::InternalLinkage, "", TheModule);
insertValue(Func, FnSignature, ModuleValues);
// Keep track of this information in a list that is emptied as functions are
// loaded...
//
FunctionSignatureList.push_back(Func);
FnSignature = read_vbr_uint(Buf, End);
BCR_TRACE(2, "Function of type: " << Ty << "\n");
}
if (hasInconsistentModuleGlobalInfo)
align32(Buf, End);
// Now that the function signature list is set up, reverse it so that we can
// remove elements efficiently from the back of the vector.
std::reverse(FunctionSignatureList.begin(), FunctionSignatureList.end());
// This is for future proofing... in the future extra fields may be added that
// we don't understand, so we transparently ignore them.
//
Buf = End;
}
void BytecodeParser::ParseVersionInfo(const unsigned char *&Buf,
const unsigned char *EndBuf) {
unsigned Version = read_vbr_uint(Buf, EndBuf);
// Unpack version number: low four bits are for flags, top bits = version
Module::Endianness Endianness;
Module::PointerSize PointerSize;
Endianness = (Version & 1) ? Module::BigEndian : Module::LittleEndian;
PointerSize = (Version & 2) ? Module::Pointer64 : Module::Pointer32;
bool hasNoEndianness = Version & 4;
bool hasNoPointerSize = Version & 8;
RevisionNum = Version >> 4;
// Default values for the current bytecode version
hasExtendedLinkageSpecs = true;
hasOldStyleVarargs = false;
hasVarArgCallPadding = false;
hasInconsistentModuleGlobalInfo = false;
hasExplicitPrimitiveZeros = false;
switch (RevisionNum) {
case 2: // LLVM pre-1.0 release: will be deleted on the next rev
// Version #2 only supported 4 linkage types. It didn't support weak
// linkage.
hasExtendedLinkageSpecs = false;
hasOldStyleVarargs = true;
hasVarArgCallPadding = true;
// FALL THROUGH
case 0: // LLVM 1.0, 1.1 release version
// Compared to rev #2, we added support for weak linkage, a more dense
// encoding, and better varargs support.
// Base LLVM 1.0 bytecode format.
hasInconsistentModuleGlobalInfo = true;
hasExplicitPrimitiveZeros = true;
// FALL THROUGH
case 1: // LLVM 1.2 release version
// LLVM 1.2 added explicit support for emitting strings efficiently.
// Also, it fixed the problem where the size of the ModuleGlobalInfo block
// included the size for the alignment at the end, where the rest of the
// blocks did not.
break;
default:
throw std::string("Unknown bytecode version number!");
}
if (hasNoEndianness) Endianness = Module::AnyEndianness;
if (hasNoPointerSize) PointerSize = Module::AnyPointerSize;
TheModule->setEndianness(Endianness);
TheModule->setPointerSize(PointerSize);
BCR_TRACE(1, "Bytecode Rev = " << (unsigned)RevisionNum << "\n");
BCR_TRACE(1, "Endianness/PointerSize = " << Endianness << ","
<< PointerSize << "\n");
}
void BytecodeParser::ParseModule(const unsigned char *Buf,
const unsigned char *EndBuf) {
unsigned Type, Size;
readBlock(Buf, EndBuf, Type, Size);
if (Type != BytecodeFormat::Module || Buf+Size != EndBuf)
throw std::string("Expected Module packet! B: "+
utostr((unsigned)(intptr_t)Buf) + ", S: "+utostr(Size)+
" E: "+utostr((unsigned)(intptr_t)EndBuf)); // Hrm, not a class?
BCR_TRACE(0, "BLOCK BytecodeFormat::Module: {\n");
FunctionSignatureList.clear(); // Just in case...
// Read into instance variables...
ParseVersionInfo(Buf, EndBuf);
align32(Buf, EndBuf);
while (Buf < EndBuf) {
const unsigned char *OldBuf = Buf;
readBlock(Buf, EndBuf, Type, Size);
switch (Type) {
case BytecodeFormat::GlobalTypePlane:
BCR_TRACE(1, "BLOCK BytecodeFormat::GlobalTypePlane: {\n");
ParseGlobalTypes(Buf, Buf+Size);
break;
case BytecodeFormat::ModuleGlobalInfo:
BCR_TRACE(1, "BLOCK BytecodeFormat::ModuleGlobalInfo: {\n");
ParseModuleGlobalInfo(Buf, Buf+Size);
break;
case BytecodeFormat::ConstantPool:
BCR_TRACE(1, "BLOCK BytecodeFormat::ConstantPool: {\n");
ParseConstantPool(Buf, Buf+Size, ModuleValues, ModuleTypeValues);
break;
case BytecodeFormat::Function: {
BCR_TRACE(1, "BLOCK BytecodeFormat::Function: {\n");
ParseFunction(Buf, Buf+Size);
break;
}
case BytecodeFormat::SymbolTable:
BCR_TRACE(1, "BLOCK BytecodeFormat::SymbolTable: {\n");
ParseSymbolTable(Buf, Buf+Size, &TheModule->getSymbolTable(), 0);
break;
default:
Buf += Size;
if (OldBuf > Buf) throw std::string("Expected Module Block!");
break;
}
BCR_TRACE(1, "} end block\n");
align32(Buf, EndBuf);
}
// After the module constant pool has been read, we can safely initialize
// global variables...
while (!GlobalInits.empty()) {
GlobalVariable *GV = GlobalInits.back().first;
unsigned Slot = GlobalInits.back().second;
GlobalInits.pop_back();
// Look up the initializer value...
// FIXME: Preserve this type ID!
unsigned TypeSlot = getTypeSlot(GV->getType()->getElementType());
if (Constant *CV = getConstantValue(TypeSlot, Slot)) {
if (GV->hasInitializer())
throw std::string("Global *already* has an initializer?!");
GV->setInitializer(CV);
} else
throw std::string("Cannot find initializer value.");
}
if (!FunctionSignatureList.empty())
throw std::string("Function expected, but bytecode stream ended!");
BCR_TRACE(0, "} end block\n\n");
}
void BytecodeParser::ParseBytecode(const unsigned char *Buf, unsigned Length,
const std::string &ModuleID) {
unsigned char *EndBuf = (unsigned char*)(Buf + Length);
// Read and check signature...
unsigned Sig = read(Buf, EndBuf);
if (Sig != ('l' | ('l' << 8) | ('v' << 16) | ('m' << 24)))
throw std::string("Invalid bytecode signature!");
TheModule = new Module(ModuleID);
try {
usesOldStyleVarargs = false;
ParseModule(Buf, EndBuf);
} catch (std::string &Error) {
freeState(); // Must destroy handles before deleting module!
delete TheModule;
TheModule = 0;
throw;
}
}
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