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//===- BitcodeReader.h - Internal BitcodeReader impl ------------*- C++ -*-===//
// The LLVM Compiler Infrastructure
// This file is distributed under the University of Illinois Open Source
// License. See LICENSE.TXT for details.
// This header defines the BitcodeReader class.
#include "llvm/GVMaterializer.h"
#include "llvm/Attributes.h"
#include "llvm/Type.h"
#include "llvm/OperandTraits.h"
#include "llvm/Bitcode/BitstreamReader.h"
#include "llvm/Bitcode/LLVMBitCodes.h"
#include "llvm/Support/ValueHandle.h"
#include "llvm/ADT/DenseMap.h"
#include <vector>
namespace llvm {
class MemoryBuffer;
class LLVMContext;
// BitcodeReaderValueList Class
class BitcodeReaderValueList {
std::vector<WeakVH> ValuePtrs;
/// ResolveConstants - As we resolve forward-referenced constants, we add
/// information about them to this vector. This allows us to resolve them in
/// bulk instead of resolving each reference at a time. See the code in
/// ResolveConstantForwardRefs for more information about this.
/// The key of this vector is the placeholder constant, the value is the slot
/// number that holds the resolved value.
typedef std::vector<std::pair<Constant*, unsigned> > ResolveConstantsTy;
ResolveConstantsTy ResolveConstants;
LLVMContext &Context;
BitcodeReaderValueList(LLVMContext &C) : Context(C) {}
~BitcodeReaderValueList() {
assert(ResolveConstants.empty() && "Constants not resolved?");
// vector compatibility methods
unsigned size() const { return ValuePtrs.size(); }
void resize(unsigned N) { ValuePtrs.resize(N); }
void push_back(Value *V) {
void clear() {
assert(ResolveConstants.empty() && "Constants not resolved?");
Value *operator[](unsigned i) const {
assert(i < ValuePtrs.size());
return ValuePtrs[i];
Value *back() const { return ValuePtrs.back(); }
void pop_back() { ValuePtrs.pop_back(); }
bool empty() const { return ValuePtrs.empty(); }
void shrinkTo(unsigned N) {
assert(N <= size() && "Invalid shrinkTo request!");
Constant *getConstantFwdRef(unsigned Idx, Type *Ty);
Value *getValueFwdRef(unsigned Idx, Type *Ty);
void AssignValue(Value *V, unsigned Idx);
/// ResolveConstantForwardRefs - Once all constants are read, this method bulk
/// resolves any forward references.
void ResolveConstantForwardRefs();
// BitcodeReaderMDValueList Class
class BitcodeReaderMDValueList {
std::vector<WeakVH> MDValuePtrs;
LLVMContext &Context;
BitcodeReaderMDValueList(LLVMContext& C) : Context(C) {}
// vector compatibility methods
unsigned size() const { return MDValuePtrs.size(); }
void resize(unsigned N) { MDValuePtrs.resize(N); }
void push_back(Value *V) { MDValuePtrs.push_back(V); }
void clear() { MDValuePtrs.clear(); }
Value *back() const { return MDValuePtrs.back(); }
void pop_back() { MDValuePtrs.pop_back(); }
bool empty() const { return MDValuePtrs.empty(); }
Value *operator[](unsigned i) const {
assert(i < MDValuePtrs.size());
return MDValuePtrs[i];
void shrinkTo(unsigned N) {
assert(N <= size() && "Invalid shrinkTo request!");
Value *getValueFwdRef(unsigned Idx);
void AssignValue(Value *V, unsigned Idx);
class BitcodeReader : public GVMaterializer {
LLVMContext &Context;
Module *TheModule;
MemoryBuffer *Buffer;
bool BufferOwned;
OwningPtr<BitstreamReader> StreamFile;
BitstreamCursor Stream;
DataStreamer *LazyStreamer;
uint64_t NextUnreadBit;
bool SeenValueSymbolTable;
const char *ErrorString;
std::vector<Type*> TypeList;
BitcodeReaderValueList ValueList;
BitcodeReaderMDValueList MDValueList;
SmallVector<Instruction *, 64> InstructionList;
SmallVector<SmallVector<uint64_t, 64>, 64> UseListRecords;
std::vector<std::pair<GlobalVariable*, unsigned> > GlobalInits;
std::vector<std::pair<GlobalAlias*, unsigned> > AliasInits;
/// MAttributes - The set of attributes by index. Index zero in the
/// file is for null, and is thus not represented here. As such all indices
/// are off by one.
std::vector<AttrListPtr> MAttributes;
/// FunctionBBs - While parsing a function body, this is a list of the basic
/// blocks for the function.
std::vector<BasicBlock*> FunctionBBs;
// When reading the module header, this list is populated with functions that
// have bodies later in the file.
std::vector<Function*> FunctionsWithBodies;
// When intrinsic functions are encountered which require upgrading they are
// stored here with their replacement function.
typedef std::vector<std::pair<Function*, Function*> > UpgradedIntrinsicMap;
UpgradedIntrinsicMap UpgradedIntrinsics;
// Map the bitcode's custom MDKind ID to the Module's MDKind ID.
DenseMap<unsigned, unsigned> MDKindMap;
// Several operations happen after the module header has been read, but
// before function bodies are processed. This keeps track of whether
// we've done this yet.
bool SeenFirstFunctionBody;
/// DeferredFunctionInfo - When function bodies are initially scanned, this
/// map contains info about where to find deferred function body in the
/// stream.
DenseMap<Function*, uint64_t> DeferredFunctionInfo;
/// BlockAddrFwdRefs - These are blockaddr references to basic blocks. These
/// are resolved lazily when functions are loaded.
typedef std::pair<unsigned, GlobalVariable*> BlockAddrRefTy;
DenseMap<Function*, std::vector<BlockAddrRefTy> > BlockAddrFwdRefs;
explicit BitcodeReader(MemoryBuffer *buffer, LLVMContext &C)
: Context(C), TheModule(0), Buffer(buffer), BufferOwned(false),
LazyStreamer(0), NextUnreadBit(0), SeenValueSymbolTable(false),
ErrorString(0), ValueList(C), MDValueList(C),
SeenFirstFunctionBody(false) {
explicit BitcodeReader(DataStreamer *streamer, LLVMContext &C)
: Context(C), TheModule(0), Buffer(0), BufferOwned(false),
LazyStreamer(streamer), NextUnreadBit(0), SeenValueSymbolTable(false),
ErrorString(0), ValueList(C), MDValueList(C),
SeenFirstFunctionBody(false) {
~BitcodeReader() {
void materializeForwardReferencedFunctions();
void FreeState();
/// setBufferOwned - If this is true, the reader will destroy the MemoryBuffer
/// when the reader is destroyed.
void setBufferOwned(bool Owned) { BufferOwned = Owned; }
virtual bool isMaterializable(const GlobalValue *GV) const;
virtual bool isDematerializable(const GlobalValue *GV) const;
virtual bool Materialize(GlobalValue *GV, std::string *ErrInfo = 0);
virtual bool MaterializeModule(Module *M, std::string *ErrInfo = 0);
virtual void Dematerialize(GlobalValue *GV);
bool Error(const char *Str) {
ErrorString = Str;
return true;
const char *getErrorString() const { return ErrorString; }
/// @brief Main interface to parsing a bitcode buffer.
/// @returns true if an error occurred.
bool ParseBitcodeInto(Module *M);
/// @brief Cheap mechanism to just extract module triple
/// @returns true if an error occurred.
bool ParseTriple(std::string &Triple);
Type *getTypeByID(unsigned ID);
Value *getFnValueByID(unsigned ID, Type *Ty) {
if (Ty && Ty->isMetadataTy())
return MDValueList.getValueFwdRef(ID);
return ValueList.getValueFwdRef(ID, Ty);
BasicBlock *getBasicBlock(unsigned ID) const {
if (ID >= FunctionBBs.size()) return 0; // Invalid ID
return FunctionBBs[ID];
AttrListPtr getAttributes(unsigned i) const {
if (i-1 < MAttributes.size())
return MAttributes[i-1];
return AttrListPtr();
/// getValueTypePair - Read a value/type pair out of the specified record from
/// slot 'Slot'. Increment Slot past the number of slots used in the record.
/// Return true on failure.
bool getValueTypePair(SmallVector<uint64_t, 64> &Record, unsigned &Slot,
unsigned InstNum, Value *&ResVal) {
if (Slot == Record.size()) return true;
unsigned ValNo = (unsigned)Record[Slot++];
if (ValNo < InstNum) {
// If this is not a forward reference, just return the value we already
// have.
ResVal = getFnValueByID(ValNo, 0);
return ResVal == 0;
} else if (Slot == Record.size()) {
return true;
unsigned TypeNo = (unsigned)Record[Slot++];
ResVal = getFnValueByID(ValNo, getTypeByID(TypeNo));
return ResVal == 0;
bool getValue(SmallVector<uint64_t, 64> &Record, unsigned &Slot,
Type *Ty, Value *&ResVal) {
if (Slot == Record.size()) return true;
unsigned ValNo = (unsigned)Record[Slot++];
ResVal = getFnValueByID(ValNo, Ty);
return ResVal == 0;
bool ParseModule(bool Resume);
bool ParseAttributeBlock();
bool ParseTypeTable();
bool ParseTypeTableBody();
bool ParseValueSymbolTable();
bool ParseConstants();
bool RememberAndSkipFunctionBody();
bool ParseFunctionBody(Function *F);
bool GlobalCleanup();
bool ResolveGlobalAndAliasInits();
bool ParseMetadata();
bool ParseMetadataAttachment();
bool ParseModuleTriple(std::string &Triple);
bool ParseUseLists();
bool InitStream();
bool InitStreamFromBuffer();
bool InitLazyStream();
bool FindFunctionInStream(Function *F,
DenseMap<Function*, uint64_t>::iterator DeferredFunctionInfoIterator);
} // End llvm namespace