class BitstreamCursor

Declaration

class BitstreamCursor : private SimpleBitstreamCursor { /* full declaration omitted */ };

Description

This represents a position within a bitcode file, implemented on top of a SimpleBitstreamCursor. Unlike iterators, BitstreamCursors are heavy-weight objects that should not be passed by value.

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:358

Inherits from: SimpleBitstreamCursor

Member Variables

private unsigned int CurCodeSize = 2

private std::vector<std::shared_ptr<BitCodeAbbrev>> CurAbbrevs

Abbrevs installed at in this block.

private SmallVector<llvm::BitstreamCursor::Block, 8> BlockScope

This tracks the codesize of parent blocks.

private llvm::BitstreamBlockInfo* BlockInfo = nullptr

public static const size_t MaxChunkSize = 32

Method Overview

• public BitstreamCursor(ArrayRef<uint8_t> BitcodeBytes)
• public BitstreamCursor(llvm::StringRef BitcodeBytes)
• public BitstreamCursor(llvm::MemoryBufferRef BitcodeBytes)
• public BitstreamCursor()
• public llvm::Error EnterSubBlock(unsigned int BlockID, unsigned int * NumWordsP = nullptr)
• public llvm::Error ReadAbbrevRecord()
• public bool ReadBlockEnd()
• public Expected<Optional<llvm::BitstreamBlockInfo>> ReadBlockInfoBlock(bool ReadBlockInfoNames = false)
• public Expected<unsigned int> ReadCode()
• public Expected<unsigned int> ReadSubBlockID()
• public llvm::Error SkipBlock()
• public Expected<llvm::BitstreamEntry> advance(unsigned int Flags = 0)
• public Expected<llvm::BitstreamEntry> advanceSkippingSubblocks(unsigned int Flags = 0)
• public Expected<const llvm::BitCodeAbbrev *> getAbbrev(unsigned int AbbrevID)
• public unsigned int getAbbrevIDWidth() const
• private void popBlockScope()
• public Expected<unsigned int> readRecord(unsigned int AbbrevID, SmallVectorImpl<uint64_t> & Vals, llvm::StringRef * Blob = nullptr)
• public void setBlockInfo(llvm::BitstreamBlockInfo * BI)
• public Expected<unsigned int> skipRecord(unsigned int AbbrevID)

Methods

¶BitstreamCursor(ArrayRef<uint8_t> BitcodeBytes)

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:382

Parameters

ArrayRef<uint8_t> BitcodeBytes

¶BitstreamCursor(llvm::StringRef BitcodeBytes)

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:384

Parameters

llvm::StringRef BitcodeBytes

¶BitstreamCursor(
    llvm::MemoryBufferRef BitcodeBytes)

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:386

Parameters

llvm::MemoryBufferRef BitcodeBytes

¶BitstreamCursor()

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:381

¶llvm::Error EnterSubBlock(
    unsigned int BlockID,
    unsigned int* NumWordsP = nullptr)

Description

Having read the ENTER_SUBBLOCK abbrevid, and enter the block.

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:516

Parameters

unsigned int BlockID

unsigned int* NumWordsP = nullptr

¶llvm::Error ReadAbbrevRecord()

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:561

¶bool ReadBlockEnd()

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:518

¶Expected<Optional<llvm::BitstreamBlockInfo>>
ReadBlockInfoBlock(
    bool ReadBlockInfoNames = false)

Description

Read and return a block info block from the bitstream. If an error was encountered, return None.

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:569

Parameters

bool ReadBlockInfoNames = false

Whether to read block/record name information in the BlockInfo block. Only llvm-bcanalyzer uses this.

¶Expected<unsigned int> ReadCode()

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:474

¶Expected<unsigned int> ReadSubBlockID()

Description

Having read the ENTER_SUBBLOCK code, read the BlockID for the block.

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:480

¶llvm::Error SkipBlock()

Description

Having read the ENTER_SUBBLOCK abbrevid and a BlockID, skip over the body of this block.

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:484

¶Expected<llvm::BitstreamEntry> advance(
    unsigned int Flags = 0)

Description

Advance the current bitstream, returning the next entry in the stream.

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:418

Parameters

unsigned int Flags = 0

¶Expected<llvm::BitstreamEntry>
advanceSkippingSubblocks(unsigned int Flags = 0)

Description

This is a convenience function for clients that don't expect any subblocks. This just skips over them automatically.

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:457

Parameters

unsigned int Flags = 0

¶Expected<const llvm::BitCodeAbbrev*> getAbbrev(
    unsigned int AbbrevID)

Description

Return the abbreviation for the specified AbbrevId.

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:543

Parameters

unsigned int AbbrevID

¶unsigned int getAbbrevIDWidth() const

Description

Return the number of bits used to encode an abbrev #.

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:404

¶void popBlockScope()

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:530

¶Expected<unsigned int> readRecord(
    unsigned int AbbrevID,
    SmallVectorImpl<uint64_t>& Vals,
    llvm::StringRef* Blob = nullptr)

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:554

Parameters

unsigned int AbbrevID

SmallVectorImpl<uint64_t>& Vals

llvm::StringRef* Blob = nullptr

¶void setBlockInfo(llvm::BitstreamBlockInfo* BI)

Description

Set the block info to be used by this BitstreamCursor to interpret abbreviated records.

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:573

Parameters

llvm::BitstreamBlockInfo* BI

¶Expected<unsigned int> skipRecord(
    unsigned int AbbrevID)

Description

Read the current record and discard it, returning the code for the record.

Declared at: llvm/include/llvm/Bitstream/BitstreamReader.h:552

Parameters

unsigned int AbbrevID