#ifndef LLVM_BITCODE_BITSTREAMREADER_H
#define LLVM_BITCODE_BITSTREAMREADER_H
-#include "llvm/ADT/OwningPtr.h"
#include "llvm/Bitcode/BitCodes.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/StreamableMemoryObject.h"
class Deserializer;
+/// BitstreamReader - This class is used to read from an LLVM bitcode stream,
+/// maintaining information that is global to decoding the entire file. While
+/// a file is being read, multiple cursors can be independently advanced or
+/// skipped around within the file. These are represented by the
+/// BitstreamCursor class.
class BitstreamReader {
public:
/// BlockInfo - This contains information emitted to BLOCKINFO_BLOCK blocks.
std::vector<std::pair<unsigned, std::string> > RecordNames;
};
private:
- OwningPtr<StreamableMemoryObject> BitcodeBytes;
+ std::unique_ptr<StreamableMemoryObject> BitcodeBytes;
std::vector<BlockInfo> BlockInfoRecords;
i != e; ++i)
if (BlockInfoRecords[i].BlockID == BlockID)
return &BlockInfoRecords[i];
- return 0;
+ return nullptr;
}
BlockInfo &getOrCreateBlockInfo(unsigned BlockID) {
BlockInfoRecords.back().BlockID = BlockID;
return BlockInfoRecords.back();
}
+};
+
+
+/// BitstreamEntry - When advancing through a bitstream cursor, each advance can
+/// discover a few different kinds of entries:
+/// Error - Malformed bitcode was found.
+/// EndBlock - We've reached the end of the current block, (or the end of the
+/// file, which is treated like a series of EndBlock records.
+/// SubBlock - This is the start of a new subblock of a specific ID.
+/// Record - This is a record with a specific AbbrevID.
+///
+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;
+ }
};
+/// BitstreamCursor - This represents a position within a bitcode file. There
+/// may be multiple independent cursors reading within one bitstream, each
+/// maintaining their own local state.
+///
+/// Unlike iterators, BitstreamCursors are heavy-weight objects that should not
+/// be passed by value.
class BitstreamCursor {
friend class Deserializer;
BitstreamReader *BitStream;
size_t NextChar;
- /// CurWord - This is the current data we have pulled from the stream but have
- /// not returned to the client.
- uint32_t CurWord;
+
+ /// CurWord/word_t - This is the current data we have pulled from the stream
+ /// but have not returned to the client. This is specifically and
+ /// intentionally defined to follow the word size of the host machine for
+ /// efficiency. We use word_t in places that are aware of this to make it
+ /// perfectly explicit what is going on.
+ typedef uint32_t word_t;
+ word_t CurWord;
/// BitsInCurWord - This is the number of bits in CurWord that are valid. This
- /// is always from [0...31] inclusive.
+ /// is always from [0...31/63] inclusive (depending on word size).
unsigned BitsInCurWord;
// CurCodeSize - This is the declared size of code values used for the current
/// BlockScope - This tracks the codesize of parent blocks.
SmallVector<Block, 8> BlockScope;
+
public:
- BitstreamCursor() : BitStream(0), NextChar(0) {
- }
- BitstreamCursor(const BitstreamCursor &RHS) : BitStream(0), NextChar(0) {
+ BitstreamCursor() : BitStream(nullptr), NextChar(0) {}
+ BitstreamCursor(const BitstreamCursor &RHS)
+ : BitStream(nullptr), NextChar(0) {
operator=(RHS);
}
void operator=(const BitstreamCursor &RHS);
void freeState();
-
- /// GetAbbrevIDWidth - Return the number of bits used to encode an abbrev #.
- unsigned GetAbbrevIDWidth() const { return CurCodeSize; }
bool isEndPos(size_t pos) {
return BitStream->getBitcodeBytes().isObjectEnd(static_cast<uint64_t>(pos));
static_cast<uint64_t>(pos - 1));
}
- unsigned char getByte(size_t pos) {
- uint8_t byte = -1;
- BitStream->getBitcodeBytes().readByte(pos, &byte);
- return byte;
- }
-
uint32_t getWord(size_t pos) {
uint8_t buf[4] = { 0xFF, 0xFF, 0xFF, 0xFF };
- BitStream->getBitcodeBytes().readBytes(pos, sizeof(buf), buf, NULL);
+ BitStream->getBitcodeBytes().readBytes(pos, sizeof(buf), buf);
return *reinterpret_cast<support::ulittle32_t *>(buf);
}
bool AtEndOfStream() {
- return isEndPos(NextChar) && BitsInCurWord == 0;
+ return BitsInCurWord == 0 && isEndPos(NextChar);
}
+ /// getAbbrevIDWidth - Return the number of bits used to encode an abbrev #.
+ unsigned getAbbrevIDWidth() const { return CurCodeSize; }
+
/// GetCurrentBitNo - Return the bit # of the bit we are reading.
uint64_t GetCurrentBitNo() const {
return NextChar*CHAR_BIT - BitsInCurWord;
return BitStream;
}
+ /// Flags that modify the behavior of advance().
+ enum {
+ /// AF_DontPopBlockAtEnd - If this flag is used, the advance() method does
+ /// not automatically pop the block scope when the end of a block is
+ /// reached.
+ AF_DontPopBlockAtEnd = 1,
+
+ /// AF_DontAutoprocessAbbrevs - If this flag is used, abbrev entries are
+ /// returned just like normal records.
+ AF_DontAutoprocessAbbrevs = 2
+ };
+
+ /// advance - Advance the current bitstream, returning the next entry in the
+ /// stream.
+ BitstreamEntry advance(unsigned Flags = 0) {
+ while (1) {
+ unsigned Code = ReadCode();
+ if (Code == bitc::END_BLOCK) {
+ // Pop the end of the block unless Flags tells us not to.
+ 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)) {
+ // We read and accumulate abbrev's, the client can't do anything with
+ // them anyway.
+ ReadAbbrevRecord();
+ continue;
+ }
+
+ return BitstreamEntry::getRecord(Code);
+ }
+ }
+
+ /// advanceSkippingSubblocks - This is a convenience function for clients that
+ /// don't expect any subblocks. This just skips over them automatically.
+ BitstreamEntry advanceSkippingSubblocks(unsigned Flags = 0) {
+ while (1) {
+ // If we found a normal entry, return it.
+ BitstreamEntry Entry = advance(Flags);
+ if (Entry.Kind != BitstreamEntry::SubBlock)
+ return Entry;
+
+ // If we found a sub-block, just skip over it and check the next entry.
+ if (SkipBlock())
+ return BitstreamEntry::getError();
+ }
+ }
/// JumpToBit - Reset the stream to the specified bit number.
void JumpToBit(uint64_t BitNo) {
- uintptr_t ByteNo = uintptr_t(BitNo/8) & ~3;
- uintptr_t WordBitNo = uintptr_t(BitNo) & 31;
+ uintptr_t ByteNo = uintptr_t(BitNo/8) & ~(sizeof(word_t)-1);
+ unsigned WordBitNo = unsigned(BitNo & (sizeof(word_t)*8-1));
assert(canSkipToPos(ByteNo) && "Invalid location");
// Move the cursor to the right word.
CurWord = 0;
// Skip over any bits that are already consumed.
- if (WordBitNo)
- Read(static_cast<unsigned>(WordBitNo));
+ if (WordBitNo) {
+ if (sizeof(word_t) > 4)
+ Read64(WordBitNo);
+ else
+ Read(WordBitNo);
+ }
}
uint32_t Read(unsigned NumBits) {
- assert(NumBits <= 32 && "Cannot return more than 32 bits!");
+ assert(NumBits && NumBits <= 32 &&
+ "Cannot return zero or more than 32 bits!");
+
// If the field is fully contained by CurWord, return it quickly.
if (BitsInCurWord >= NumBits) {
- uint32_t R = CurWord & ((1U << NumBits)-1);
+ uint32_t R = uint32_t(CurWord) & (~0U >> (32-NumBits));
CurWord >>= NumBits;
BitsInCurWord -= NumBits;
return R;
return 0;
}
- unsigned R = CurWord;
+ uint32_t R = uint32_t(CurWord);
// Read the next word from the stream.
- CurWord = getWord(NextChar);
- NextChar += 4;
+ uint8_t Array[sizeof(word_t)] = {0};
+
+ BitStream->getBitcodeBytes().readBytes(NextChar, sizeof(Array), Array);
+
+ // Handle big-endian byte-swapping if necessary.
+ support::detail::packed_endian_specific_integral
+ <word_t, support::little, support::unaligned> EndianValue;
+ memcpy(&EndianValue, Array, sizeof(Array));
+
+ CurWord = EndianValue;
+
+ NextChar += sizeof(word_t);
// Extract NumBits-BitsInCurWord from what we just read.
unsigned BitsLeft = NumBits-BitsInCurWord;
- // Be careful here, BitsLeft is in the range [1..32] inclusive.
- R |= (CurWord & (~0U >> (32-BitsLeft))) << BitsInCurWord;
+ // Be careful here, BitsLeft is in the range [1..32]/[1..64] inclusive.
+ R |= uint32_t((CurWord & (word_t(~0ULL) >> (sizeof(word_t)*8-BitsLeft)))
+ << BitsInCurWord);
- // BitsLeft bits have just been used up from CurWord.
- if (BitsLeft != 32)
+ // BitsLeft bits have just been used up from CurWord. BitsLeft is in the
+ // range [1..32]/[1..64] so be careful how we shift.
+ if (BitsLeft != sizeof(word_t)*8)
CurWord >>= BitsLeft;
else
CurWord = 0;
- BitsInCurWord = 32-BitsLeft;
+ BitsInCurWord = sizeof(word_t)*8-BitsLeft;
return R;
}
}
}
- void SkipToWord() {
+private:
+ void SkipToFourByteBoundary() {
+ // If word_t is 64-bits and if we've read less than 32 bits, just dump
+ // the bits we have up to the next 32-bit boundary.
+ if (sizeof(word_t) > 4 &&
+ BitsInCurWord >= 32) {
+ CurWord >>= BitsInCurWord-32;
+ BitsInCurWord = 32;
+ return;
+ }
+
BitsInCurWord = 0;
CurWord = 0;
}
+public:
unsigned ReadCode() {
return Read(CurCodeSize);
// Read and ignore the codelen value. Since we are skipping this block, we
// don't care what code widths are used inside of it.
ReadVBR(bitc::CodeLenWidth);
- SkipToWord();
- unsigned NumWords = Read(bitc::BlockSizeWidth);
+ SkipToFourByteBoundary();
+ unsigned NumFourBytes = Read(bitc::BlockSizeWidth);
// Check that the block wasn't partially defined, and that the offset isn't
// bogus.
- size_t SkipTo = NextChar + NumWords*4;
- if (AtEndOfStream() || !canSkipToPos(SkipTo))
+ size_t SkipTo = GetCurrentBitNo() + NumFourBytes*4*8;
+ if (AtEndOfStream() || !canSkipToPos(SkipTo/8))
return true;
- NextChar = SkipTo;
+ JumpToBit(SkipTo);
return false;
}
/// EnterSubBlock - Having read the ENTER_SUBBLOCK abbrevid, enter
/// the block, and return true if the block has an error.
- bool EnterSubBlock(unsigned BlockID, unsigned *NumWordsP = 0);
-
+ bool EnterSubBlock(unsigned BlockID, unsigned *NumWordsP = nullptr);
+
bool ReadBlockEnd() {
if (BlockScope.empty()) return true;
// Block tail:
// [END_BLOCK, <align4bytes>]
- SkipToWord();
+ SkipToFourByteBoundary();
- PopBlockScope();
+ popBlockScope();
return false;
}
private:
- void PopBlockScope() {
+
+ void popBlockScope() {
CurCodeSize = BlockScope.back().PrevCodeSize;
// Delete abbrevs from popped scope.
BlockScope.pop_back();
}
- //===--------------------------------------------------------------------===//
+ //===--------------------------------------------------------------------===//
// Record Processing
//===--------------------------------------------------------------------===//
private:
- void ReadAbbreviatedLiteral(const BitCodeAbbrevOp &Op,
- SmallVectorImpl<uint64_t> &Vals) {
- assert(Op.isLiteral() && "Not a literal");
- // If the abbrev specifies the literal value to use, use it.
- Vals.push_back(Op.getLiteralValue());
- }
-
- void ReadAbbreviatedField(const BitCodeAbbrevOp &Op,
- SmallVectorImpl<uint64_t> &Vals) {
- assert(!Op.isLiteral() && "Use ReadAbbreviatedLiteral for literals!");
-
- // Decode the value as we are commanded.
- switch (Op.getEncoding()) {
- default: llvm_unreachable("Unknown encoding!");
- case BitCodeAbbrevOp::Fixed:
- Vals.push_back(Read((unsigned)Op.getEncodingData()));
- break;
- case BitCodeAbbrevOp::VBR:
- Vals.push_back(ReadVBR64((unsigned)Op.getEncodingData()));
- break;
- case BitCodeAbbrevOp::Char6:
- Vals.push_back(BitCodeAbbrevOp::DecodeChar6(Read(6)));
- break;
- }
- }
+ void readAbbreviatedLiteral(const BitCodeAbbrevOp &Op,
+ SmallVectorImpl<uint64_t> &Vals);
+ void readAbbreviatedField(const BitCodeAbbrevOp &Op,
+ SmallVectorImpl<uint64_t> &Vals);
+ void skipAbbreviatedField(const BitCodeAbbrevOp &Op);
+
public:
/// getAbbrev - Return the abbreviation for the specified AbbrevId.
return CurAbbrevs[AbbrevNo];
}
- unsigned ReadRecord(unsigned AbbrevID, SmallVectorImpl<uint64_t> &Vals,
- const char **BlobStart = 0, unsigned *BlobLen = 0);
-
- unsigned ReadRecord(unsigned AbbrevID, SmallVectorImpl<uint64_t> &Vals,
- const char *&BlobStart, unsigned &BlobLen) {
- return ReadRecord(AbbrevID, Vals, &BlobStart, &BlobLen);
- }
+ /// skipRecord - Read the current record and discard it.
+ void skipRecord(unsigned AbbrevID);
+ unsigned readRecord(unsigned AbbrevID, SmallVectorImpl<uint64_t> &Vals,
+ StringRef *Blob = nullptr);
//===--------------------------------------------------------------------===//
// Abbrev Processing
//===--------------------------------------------------------------------===//
-
void ReadAbbrevRecord();
-
+
bool ReadBlockInfoBlock();
};
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