#ifndef LLVM_BITCODE_BITSTREAMREADER_H
#define LLVM_BITCODE_BITSTREAMREADER_H
#include "llvm/Bitcode/BitCodes.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/StreamingMemoryObject.h"
#include <climits>
#include <string>
#include <vector>
namespace llvm {
class Deserializer;
class BitstreamReader {
public:
struct BlockInfo {
unsigned BlockID;
std::vector<IntrusiveRefCntPtr<BitCodeAbbrev>> Abbrevs;
std::string Name;
std::vector<std::pair<unsigned, std::string> > RecordNames;
};
private:
std::unique_ptr<MemoryObject> BitcodeBytes;
std::vector<BlockInfo> BlockInfoRecords;
bool IgnoreBlockInfoNames;
BitstreamReader(const BitstreamReader&) LLVM_DELETED_FUNCTION;
void operator=(const BitstreamReader&) LLVM_DELETED_FUNCTION;
public:
BitstreamReader() : IgnoreBlockInfoNames(true) {
}
BitstreamReader(const unsigned char *Start, const unsigned char *End)
: IgnoreBlockInfoNames(true) {
init(Start, End);
}
BitstreamReader(std::unique_ptr<MemoryObject> BitcodeBytes)
: BitcodeBytes(std::move(BitcodeBytes)), IgnoreBlockInfoNames(true) {}
BitstreamReader(BitstreamReader &&Other) {
*this = std::move(Other);
}
BitstreamReader &operator=(BitstreamReader &&Other) {
BitcodeBytes = std::move(Other.BitcodeBytes);
std::swap(BlockInfoRecords, Other.BlockInfoRecords);
IgnoreBlockInfoNames = Other.IgnoreBlockInfoNames;
return *this;
}
void init(const unsigned char *Start, const unsigned char *End) {
assert(((End-Start) & 3) == 0 &&"Bitcode stream not a multiple of 4 bytes");
BitcodeBytes.reset(getNonStreamedMemoryObject(Start, End));
}
MemoryObject &getBitcodeBytes() { return *BitcodeBytes; }
void CollectBlockInfoNames() { IgnoreBlockInfoNames = false; }
bool isIgnoringBlockInfoNames() { return IgnoreBlockInfoNames; }
bool hasBlockInfoRecords() const { return !BlockInfoRecords.empty(); }
const BlockInfo *getBlockInfo(unsigned BlockID) const {
if (!BlockInfoRecords.empty() && BlockInfoRecords.back().BlockID == BlockID)
return &BlockInfoRecords.back();
for (unsigned i = 0, e = static_cast<unsigned>(BlockInfoRecords.size());
i != e; ++i)
if (BlockInfoRecords[i].BlockID == BlockID)
return &BlockInfoRecords[i];
return nullptr;
}
BlockInfo &getOrCreateBlockInfo(unsigned BlockID) {
if (const BlockInfo *BI = getBlockInfo(BlockID))
return *const_cast<BlockInfo*>(BI);
BlockInfoRecords.push_back(BlockInfo());
BlockInfoRecords.back().BlockID = BlockID;
return BlockInfoRecords.back();
}
void takeBlockInfo(BitstreamReader &&Other) {
assert(!hasBlockInfoRecords());
BlockInfoRecords = std::move(Other.BlockInfoRecords);
}
};
struct BitstreamEntry {
enum {
Error, EndBlock, SubBlock, Record } Kind;
unsigned ID;
static BitstreamEntry getError() {
BitstreamEntry E; E.Kind = Error; return E;
}
static BitstreamEntry getEndBlock() {
BitstreamEntry E; E.Kind = EndBlock; return E;
}
static BitstreamEntry getSubBlock(unsigned ID) {
BitstreamEntry E; E.Kind = SubBlock; E.ID = ID; return E;
}
static BitstreamEntry getRecord(unsigned AbbrevID) {
BitstreamEntry E; E.Kind = Record; E.ID = AbbrevID; return E;
}
};
class BitstreamCursor {
friend class Deserializer;
BitstreamReader *BitStream;
size_t NextChar;
size_t Size;
typedef size_t word_t;
word_t CurWord;
unsigned BitsInCurWord;
unsigned CurCodeSize;
std::vector<IntrusiveRefCntPtr<BitCodeAbbrev>> CurAbbrevs;
struct Block {
unsigned PrevCodeSize;
std::vector<IntrusiveRefCntPtr<BitCodeAbbrev>> PrevAbbrevs;
explicit Block(unsigned PCS) : PrevCodeSize(PCS) {}
};
SmallVector<Block, 8> BlockScope;
public:
BitstreamCursor() { init(nullptr); }
explicit BitstreamCursor(BitstreamReader &R) { init(&R); }
void init(BitstreamReader *R) {
freeState();
BitStream = R;
NextChar = 0;
Size = 0;
BitsInCurWord = 0;
CurCodeSize = 2;
}
void freeState();
bool canSkipToPos(size_t pos) const {
return pos == 0 || BitStream->getBitcodeBytes().isValidAddress(
static_cast<uint64_t>(pos - 1));
}
bool AtEndOfStream() {
if (BitsInCurWord != 0)
return false;
if (Size != 0)
return Size == NextChar;
fillCurWord();
return BitsInCurWord == 0;
}
unsigned getAbbrevIDWidth() const { return CurCodeSize; }
uint64_t GetCurrentBitNo() const {
return NextChar*CHAR_BIT - BitsInCurWord;
}
BitstreamReader *getBitStreamReader() {
return BitStream;
}
const BitstreamReader *getBitStreamReader() const {
return BitStream;
}
enum {
AF_DontPopBlockAtEnd = 1,
AF_DontAutoprocessAbbrevs = 2
};
BitstreamEntry advance(unsigned Flags = 0) {
while (1) {
unsigned Code = ReadCode();
if (Code == bitc::END_BLOCK) {
if (!(Flags & AF_DontPopBlockAtEnd) && ReadBlockEnd())
return BitstreamEntry::getError();
return BitstreamEntry::getEndBlock();
}
if (Code == bitc::ENTER_SUBBLOCK)
return BitstreamEntry::getSubBlock(ReadSubBlockID());
if (Code == bitc::DEFINE_ABBREV &&
!(Flags & AF_DontAutoprocessAbbrevs)) {
ReadAbbrevRecord();
continue;
}
return BitstreamEntry::getRecord(Code);
}
}
BitstreamEntry advanceSkippingSubblocks(unsigned Flags = 0) {
while (1) {
BitstreamEntry Entry = advance(Flags);
if (Entry.Kind != BitstreamEntry::SubBlock)
return Entry;
if (SkipBlock())
return BitstreamEntry::getError();
}
}
void JumpToBit(uint64_t BitNo) {
size_t ByteNo = size_t(BitNo/8) & ~(sizeof(word_t)-1);
unsigned WordBitNo = unsigned(BitNo & (sizeof(word_t)*8-1));
assert(canSkipToPos(ByteNo) && "Invalid location");
NextChar = ByteNo;
BitsInCurWord = 0;
if (WordBitNo)
Read(WordBitNo);
}
void fillCurWord() {
if (Size != 0 && NextChar >= Size)
report_fatal_error("Unexpected end of file");
uint8_t Array[sizeof(word_t)] = {0};
uint64_t BytesRead =
BitStream->getBitcodeBytes().readBytes(Array, sizeof(Array), NextChar);
if (BytesRead == 0) {
Size = NextChar;
return;
}
CurWord =
support::endian::read<word_t, support::little, support::unaligned>(
Array);
NextChar += BytesRead;
BitsInCurWord = BytesRead * 8;
}
word_t Read(unsigned NumBits) {
static const unsigned BitsInWord = sizeof(word_t) * 8;
assert(NumBits && NumBits <= BitsInWord &&
"Cannot return zero or more than BitsInWord bits!");
static const unsigned Mask = sizeof(word_t) > 4 ? 0x3f : 0x1f;
if (BitsInCurWord >= NumBits) {
word_t R = CurWord & (~word_t(0) >> (BitsInWord - NumBits));
CurWord >>= (NumBits & Mask);
BitsInCurWord -= NumBits;
return R;
}
word_t R = BitsInCurWord ? CurWord : 0;
unsigned BitsLeft = NumBits - BitsInCurWord;
fillCurWord();
if (BitsLeft > BitsInCurWord)
return 0;
word_t R2 = CurWord & (~word_t(0) >> (BitsInWord - BitsLeft));
CurWord >>= (BitsLeft & Mask);
BitsInCurWord -= BitsLeft;
R |= R2 << (NumBits - BitsLeft);
return R;
}
uint32_t ReadVBR(unsigned NumBits) {
uint32_t Piece = Read(NumBits);
if ((Piece & (1U << (NumBits-1))) == 0)
return Piece;
uint32_t Result = 0;
unsigned NextBit = 0;
while (1) {
Result |= (Piece & ((1U << (NumBits-1))-1)) << NextBit;
if ((Piece & (1U << (NumBits-1))) == 0)
return Result;
NextBit += NumBits-1;
Piece = Read(NumBits);
}
}
uint64_t ReadVBR64(unsigned NumBits) {
uint32_t Piece = Read(NumBits);
if ((Piece & (1U << (NumBits-1))) == 0)
return uint64_t(Piece);
uint64_t Result = 0;
unsigned NextBit = 0;
while (1) {
Result |= uint64_t(Piece & ((1U << (NumBits-1))-1)) << NextBit;
if ((Piece & (1U << (NumBits-1))) == 0)
return Result;
NextBit += NumBits-1;
Piece = Read(NumBits);
}
}
private:
void SkipToFourByteBoundary() {
if (sizeof(word_t) > 4 &&
BitsInCurWord >= 32) {
CurWord >>= BitsInCurWord-32;
BitsInCurWord = 32;
return;
}
BitsInCurWord = 0;
}
public:
unsigned ReadCode() {
return Read(CurCodeSize);
}
unsigned ReadSubBlockID() {
return ReadVBR(bitc::BlockIDWidth);
}
bool SkipBlock() {
ReadVBR(bitc::CodeLenWidth);
SkipToFourByteBoundary();
unsigned NumFourBytes = Read(bitc::BlockSizeWidth);
size_t SkipTo = GetCurrentBitNo() + NumFourBytes*4*8;
if (AtEndOfStream() || !canSkipToPos(SkipTo/8))
return true;
JumpToBit(SkipTo);
return false;
}
bool EnterSubBlock(unsigned BlockID, unsigned *NumWordsP = nullptr);
bool ReadBlockEnd() {
if (BlockScope.empty()) return true;
SkipToFourByteBoundary();
popBlockScope();
return false;
}
private:
void popBlockScope() {
CurCodeSize = BlockScope.back().PrevCodeSize;
CurAbbrevs = std::move(BlockScope.back().PrevAbbrevs);
BlockScope.pop_back();
}
public:
const BitCodeAbbrev *getAbbrev(unsigned AbbrevID) {
unsigned AbbrevNo = AbbrevID - bitc::FIRST_APPLICATION_ABBREV;
if (AbbrevNo >= CurAbbrevs.size())
report_fatal_error("Invalid abbrev number");
return CurAbbrevs[AbbrevNo].get();
}
void skipRecord(unsigned AbbrevID);
unsigned readRecord(unsigned AbbrevID, SmallVectorImpl<uint64_t> &Vals,
StringRef *Blob = nullptr);
void ReadAbbrevRecord();
bool ReadBlockInfoBlock();
};
}
#endif