LLVM 17.0.0git
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llvm::BitstreamCursor Class Reference

This represents a position within a bitcode file, implemented on top of a SimpleBitstreamCursor. More...

#include "llvm/Bitstream/BitstreamReader.h"

Inheritance diagram for llvm::BitstreamCursor:
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Collaboration diagram for llvm::BitstreamCursor:
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Public Types

enum  { AF_DontPopBlockAtEnd = 1 , AF_DontAutoprocessAbbrevs = 2 }
 Flags that modify the behavior of advance(). More...
 

Public Member Functions

 BitstreamCursor ()=default
 
 BitstreamCursor (ArrayRef< uint8_t > BitcodeBytes)
 
 BitstreamCursor (StringRef BitcodeBytes)
 
 BitstreamCursor (MemoryBufferRef BitcodeBytes)
 
unsigned getAbbrevIDWidth () const
 Return the number of bits used to encode an abbrev #.
 
Expected< BitstreamEntryadvance (unsigned Flags=0)
 Advance the current bitstream, returning the next entry in the stream.
 
Expected< BitstreamEntryadvanceSkippingSubblocks (unsigned Flags=0)
 This is a convenience function for clients that don't expect any subblocks.
 
Expected< unsignedReadCode ()
 
Expected< unsignedReadSubBlockID ()
 Having read the ENTER_SUBBLOCK code, read the BlockID for the block.
 
Error SkipBlock ()
 Having read the ENTER_SUBBLOCK abbrevid and a BlockID, skip over the body of this block.
 
Error EnterSubBlock (unsigned BlockID, unsigned *NumWordsP=nullptr)
 Having read the ENTER_SUBBLOCK abbrevid, and enter the block.
 
bool ReadBlockEnd ()
 
Expected< const BitCodeAbbrev * > getAbbrev (unsigned AbbrevID)
 Return the abbreviation for the specified AbbrevId.
 
Expected< unsignedskipRecord (unsigned AbbrevID)
 Read the current record and discard it, returning the code for the record.
 
Expected< unsignedreadRecord (unsigned AbbrevID, SmallVectorImpl< uint64_t > &Vals, StringRef *Blob=nullptr)
 
Error ReadAbbrevRecord ()
 
Expected< std::optional< BitstreamBlockInfo > > ReadBlockInfoBlock (bool ReadBlockInfoNames=false)
 Read and return a block info block from the bitstream.
 
void setBlockInfo (BitstreamBlockInfo *BI)
 Set the block info to be used by this BitstreamCursor to interpret abbreviated records.
 
bool AtEndOfStream ()
 
bool canSkipToPos (size_t pos) const
 
Error fillCurWord ()
 
ArrayRef< uint8_t > getBitcodeBytes () const
 
uint64_t GetCurrentBitNo () const
 Return the bit # of the bit we are reading.
 
uint64_t getCurrentByteNo () const
 
const uint8_t * getPointerToByte (uint64_t ByteNo, uint64_t NumBytes)
 Get a pointer into the bitstream at the specified byte offset.
 
Error JumpToBit (uint64_t BitNo)
 Reset the stream to the specified bit number.
 
Expected< word_tRead (unsigned NumBits)
 
Expected< uint32_tReadVBR (const unsigned NumBits)
 
Expected< uint64_tReadVBR64 (const unsigned NumBits)
 
size_t SizeInBytes () const
 Return the size of the stream in bytes.
 
void skipToEnd ()
 Skip to the end of the file.
 

Static Public Attributes

static const size_t MaxChunkSize = 32
 

Detailed 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.

Definition at line 358 of file BitstreamReader.h.

Member Enumeration Documentation

◆ anonymous enum

anonymous enum

Flags that modify the behavior of advance().

Enumerator
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_DontAutoprocessAbbrevs 

If this flag is used, abbrev entries are returned just like normal records.

Definition at line 407 of file BitstreamReader.h.

Constructor & Destructor Documentation

◆ BitstreamCursor() [1/4]

llvm::BitstreamCursor::BitstreamCursor ( )
default

◆ BitstreamCursor() [2/4]

llvm::BitstreamCursor::BitstreamCursor ( ArrayRef< uint8_t >  BitcodeBytes)
inlineexplicit

Definition at line 382 of file BitstreamReader.h.

◆ BitstreamCursor() [3/4]

llvm::BitstreamCursor::BitstreamCursor ( StringRef  BitcodeBytes)
inlineexplicit

Definition at line 384 of file BitstreamReader.h.

◆ BitstreamCursor() [4/4]

llvm::BitstreamCursor::BitstreamCursor ( MemoryBufferRef  BitcodeBytes)
inlineexplicit

Definition at line 386 of file BitstreamReader.h.

Member Function Documentation

◆ advance()

Expected< BitstreamEntry > llvm::BitstreamCursor::advance ( unsigned  Flags = 0)
inline

◆ advanceSkippingSubblocks()

Expected< BitstreamEntry > llvm::BitstreamCursor::advanceSkippingSubblocks ( unsigned  Flags = 0)
inline

This is a convenience function for clients that don't expect any subblocks.

This just skips over them automatically.

Definition at line 457 of file BitstreamReader.h.

References advance(), llvm::Expected< T >::get(), SkipBlock(), and llvm::BitstreamEntry::SubBlock.

Referenced by getEnableSplitLTOUnitFlag(), hasObjCCategoryInModule(), ReadBlockInfoBlock(), and readModuleTriple().

◆ AtEndOfStream()

bool llvm::SimpleBitstreamCursor::AtEndOfStream ( )
inline

◆ canSkipToPos()

bool llvm::SimpleBitstreamCursor::canSkipToPos ( size_t  pos) const
inline

Definition at line 107 of file BitstreamReader.h.

Referenced by hasInvalidBitcodeHeader(), readRecord(), SkipBlock(), and skipRecord().

◆ EnterSubBlock()

Error BitstreamCursor::EnterSubBlock ( unsigned  BlockID,
unsigned NumWordsP = nullptr 
)

◆ fillCurWord()

Error llvm::SimpleBitstreamCursor::fillCurWord ( )
inline

Definition at line 160 of file BitstreamReader.h.

◆ getAbbrev()

Expected< const BitCodeAbbrev * > llvm::BitstreamCursor::getAbbrev ( unsigned  AbbrevID)
inline

Return the abbreviation for the specified AbbrevId.

Definition at line 543 of file BitstreamReader.h.

References llvm::createStringError(), and llvm::bitc::FIRST_APPLICATION_ABBREV.

Referenced by readRecord(), and skipRecord().

◆ getAbbrevIDWidth()

unsigned llvm::BitstreamCursor::getAbbrevIDWidth ( ) const
inline

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

Definition at line 404 of file BitstreamReader.h.

◆ getBitcodeBytes()

ArrayRef< uint8_t > llvm::SimpleBitstreamCursor::getBitcodeBytes ( ) const
inline

◆ GetCurrentBitNo()

uint64_t llvm::SimpleBitstreamCursor::GetCurrentBitNo ( ) const
inline

Return the bit # of the bit we are reading.

Definition at line 117 of file BitstreamReader.h.

Referenced by llvm::getBitcodeFileContents(), isBlock(), jumpToValueSymbolTable(), readRecord(), SkipBlock(), and skipRecord().

◆ getCurrentByteNo()

uint64_t llvm::SimpleBitstreamCursor::getCurrentByteNo ( ) const
inline

Definition at line 122 of file BitstreamReader.h.

Referenced by llvm::getBitcodeFileContents().

◆ getPointerToByte()

const uint8_t * llvm::SimpleBitstreamCursor::getPointerToByte ( uint64_t  ByteNo,
uint64_t  NumBytes 
)
inline

Get a pointer into the bitstream at the specified byte offset.

Definition at line 148 of file BitstreamReader.h.

◆ JumpToBit()

Error llvm::SimpleBitstreamCursor::JumpToBit ( uint64_t  BitNo)
inline

◆ Read()

Expected< word_t > llvm::SimpleBitstreamCursor::Read ( unsigned  NumBits)
inline

◆ ReadAbbrevRecord()

Error BitstreamCursor::ReadAbbrevRecord ( )

◆ ReadBlockEnd()

bool llvm::BitstreamCursor::ReadBlockEnd ( )
inline

◆ ReadBlockInfoBlock()

Expected< std::optional< BitstreamBlockInfo > > BitstreamCursor::ReadBlockInfoBlock ( bool  ReadBlockInfoNames = false)

◆ ReadCode()

Expected< unsigned > llvm::BitstreamCursor::ReadCode ( )
inline

Definition at line 474 of file BitstreamReader.h.

References Read().

Referenced by advance(), and llvm::BitcodeAnalyzer::analyze().

◆ readRecord()

Expected< unsigned > BitstreamCursor::readRecord ( unsigned  AbbrevID,
SmallVectorImpl< uint64_t > &  Vals,
StringRef Blob = nullptr 
)

◆ ReadSubBlockID()

Expected< unsigned > llvm::BitstreamCursor::ReadSubBlockID ( )
inline

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

Definition at line 480 of file BitstreamReader.h.

References llvm::bitc::BlockIDWidth, and ReadVBR().

Referenced by advance(), and llvm::BitcodeAnalyzer::analyze().

◆ ReadVBR()

Expected< uint32_t > llvm::SimpleBitstreamCursor::ReadVBR ( const unsigned  NumBits)
inline

◆ ReadVBR64()

Expected< uint64_t > llvm::SimpleBitstreamCursor::ReadVBR64 ( const unsigned  NumBits)
inline

Definition at line 264 of file BitstreamReader.h.

Referenced by readAbbreviatedField(), ReadAbbrevRecord(), readRecord(), and skipRecord().

◆ setBlockInfo()

void llvm::BitstreamCursor::setBlockInfo ( BitstreamBlockInfo BI)
inline

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

Definition at line 573 of file BitstreamReader.h.

Referenced by llvm::BitcodeAnalyzer::analyze(), and llvm::remarks::BitstreamParserHelper::parseBlockInfoBlock().

◆ SizeInBytes()

size_t llvm::SimpleBitstreamCursor::SizeInBytes ( ) const
inline

Return the size of the stream in bytes.

Definition at line 310 of file BitstreamReader.h.

◆ SkipBlock()

Error llvm::BitstreamCursor::SkipBlock ( )
inline

◆ skipRecord()

Expected< unsigned > BitstreamCursor::skipRecord ( unsigned  AbbrevID)

◆ skipToEnd()

void llvm::SimpleBitstreamCursor::skipToEnd ( )
inline

Skip to the end of the file.

Definition at line 313 of file BitstreamReader.h.

Referenced by skipRecord(), and llvm::remarks::BitstreamParserHelper::skipToEnd().

Member Data Documentation

◆ MaxChunkSize

const size_t llvm::BitstreamCursor::MaxChunkSize = 32
static

The documentation for this class was generated from the following files: