lib/Bitcode/Reader/BitstreamReader.cpp - fp2-dev/platform/external/llvm - Gitiles

 //===- BitstreamReader.cpp - BitstreamReader implementation ---------------===//
 //
 //                     The LLVM Compiler Infrastructure
 //
 // This file is distributed under the University of Illinois Open Source
 // License. See LICENSE.TXT for details.
 //
 //===----------------------------------------------------------------------===//

 #include "llvm/Bitcode/BitstreamReader.h"

 using namespace llvm;

 //===----------------------------------------------------------------------===//
 //  BitstreamCursor implementation
 //===----------------------------------------------------------------------===//

 void BitstreamCursor::operator=(const BitstreamCursor &RHS) {
   freeState();

   BitStream = RHS.BitStream;
   NextChar = RHS.NextChar;
   CurWord = RHS.CurWord;
   BitsInCurWord = RHS.BitsInCurWord;
   CurCodeSize = RHS.CurCodeSize;

   // Copy abbreviations, and bump ref counts.
   CurAbbrevs = RHS.CurAbbrevs;
   for (unsigned i = 0, e = static_cast<unsigned>(CurAbbrevs.size());
        i != e; ++i)
     CurAbbrevs[i]->addRef();

   // Copy block scope and bump ref counts.
   BlockScope = RHS.BlockScope;
   for (unsigned S = 0, e = static_cast<unsigned>(BlockScope.size());
        S != e; ++S) {
     std::vector<BitCodeAbbrev*> &Abbrevs = BlockScope[S].PrevAbbrevs;
     for (unsigned i = 0, e = static_cast<unsigned>(Abbrevs.size());
          i != e; ++i)
       Abbrevs[i]->addRef();
   }
 }

 void BitstreamCursor::freeState() {
   // Free all the Abbrevs.
   for (unsigned i = 0, e = static_cast<unsigned>(CurAbbrevs.size());
        i != e; ++i)
     CurAbbrevs[i]->dropRef();
   CurAbbrevs.clear();

   // Free all the Abbrevs in the block scope.
   for (unsigned S = 0, e = static_cast<unsigned>(BlockScope.size());
        S != e; ++S) {
     std::vector<BitCodeAbbrev*> &Abbrevs = BlockScope[S].PrevAbbrevs;
     for (unsigned i = 0, e = static_cast<unsigned>(Abbrevs.size());
          i != e; ++i)
       Abbrevs[i]->dropRef();
   }
   BlockScope.clear();
 }

 /// EnterSubBlock - Having read the ENTER_SUBBLOCK abbrevid, enter
 /// the block, and return true if the block has an error.
 bool BitstreamCursor::EnterSubBlock(unsigned BlockID, unsigned *NumWordsP) {
   // Save the current block's state on BlockScope.
   BlockScope.push_back(Block(CurCodeSize));
   BlockScope.back().PrevAbbrevs.swap(CurAbbrevs);

   // Add the abbrevs specific to this block to the CurAbbrevs list.
   if (const BitstreamReader::BlockInfo *Info =
       BitStream->getBlockInfo(BlockID)) {
     for (unsigned i = 0, e = static_cast<unsigned>(Info->Abbrevs.size());
          i != e; ++i) {
       CurAbbrevs.push_back(Info->Abbrevs[i]);
       CurAbbrevs.back()->addRef();
     }
   }

   // Get the codesize of this block.
   CurCodeSize = ReadVBR(bitc::CodeLenWidth);
   SkipToWord();
   unsigned NumWords = Read(bitc::BlockSizeWidth);
   if (NumWordsP) *NumWordsP = NumWords;

   // Validate that this block is sane.
   if (CurCodeSize == 0 || AtEndOfStream())
     return true;

   return false;
 }


 unsigned BitstreamCursor::ReadRecord(unsigned AbbrevID,
                                      SmallVectorImpl<uint64_t> &Vals,
                                      const char **BlobStart, unsigned *BlobLen){
   if (AbbrevID == bitc::UNABBREV_RECORD) {
     unsigned Code = ReadVBR(6);
     unsigned NumElts = ReadVBR(6);
     for (unsigned i = 0; i != NumElts; ++i)
       Vals.push_back(ReadVBR64(6));
     return Code;
   }

   const BitCodeAbbrev *Abbv = getAbbrev(AbbrevID);

   for (unsigned i = 0, e = Abbv->getNumOperandInfos(); i != e; ++i) {
     const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);
     if (Op.isLiteral()) {
       ReadAbbreviatedLiteral(Op, Vals);
       continue;
     }

     if (Op.getEncoding() != BitCodeAbbrevOp::Array &&
         Op.getEncoding() != BitCodeAbbrevOp::Blob) {
       ReadAbbreviatedField(Op, Vals);
       continue;
     }

     if (Op.getEncoding() == BitCodeAbbrevOp::Array) {
       // Array case.  Read the number of elements as a vbr6.
       unsigned NumElts = ReadVBR(6);

       // Get the element encoding.
       assert(i+2 == e && "array op not second to last?");
       const BitCodeAbbrevOp &EltEnc = Abbv->getOperandInfo(++i);

       // Read all the elements.
       for (; NumElts; --NumElts)
         ReadAbbreviatedField(EltEnc, Vals);
       continue;
     }

     assert(Op.getEncoding() == BitCodeAbbrevOp::Blob);
     // Blob case.  Read the number of bytes as a vbr6.
     unsigned NumElts = ReadVBR(6);
     SkipToWord();  // 32-bit alignment

     // Figure out where the end of this blob will be including tail padding.
     size_t NewEnd = NextChar+((NumElts+3)&~3);

     // If this would read off the end of the bitcode file, just set the
     // record to empty and return.
     if (!canSkipToPos(NewEnd)) {
       Vals.append(NumElts, 0);
       NextChar = BitStream->getBitcodeBytes().getExtent();
       break;
     }

     // Otherwise, read the number of bytes.  If we can return a reference to
     // the data, do so to avoid copying it.
     if (BlobStart) {
       *BlobStart = (const char*)BitStream->getBitcodeBytes().getPointer(
                                                             NextChar, NumElts);
       *BlobLen = NumElts;
     } else {
       for (; NumElts; ++NextChar, --NumElts)
         Vals.push_back(getByte(NextChar));
     }
     // Skip over tail padding.
     NextChar = NewEnd;
   }

   unsigned Code = (unsigned)Vals[0];
   Vals.erase(Vals.begin());
   return Code;
 }


 void BitstreamCursor::ReadAbbrevRecord() {
   BitCodeAbbrev *Abbv = new BitCodeAbbrev();
   unsigned NumOpInfo = ReadVBR(5);
   for (unsigned i = 0; i != NumOpInfo; ++i) {
     bool IsLiteral = Read(1) ? true : false;
     if (IsLiteral) {
       Abbv->Add(BitCodeAbbrevOp(ReadVBR64(8)));
       continue;
     }

     BitCodeAbbrevOp::Encoding E = (BitCodeAbbrevOp::Encoding)Read(3);
     if (BitCodeAbbrevOp::hasEncodingData(E))
       Abbv->Add(BitCodeAbbrevOp(E, ReadVBR64(5)));
     else
       Abbv->Add(BitCodeAbbrevOp(E));
   }
   CurAbbrevs.push_back(Abbv);
 }

 bool BitstreamCursor::ReadBlockInfoBlock() {
   // If this is the second stream to get to the block info block, skip it.
   if (BitStream->hasBlockInfoRecords())
     return SkipBlock();

   if (EnterSubBlock(bitc::BLOCKINFO_BLOCK_ID)) return true;

   SmallVector<uint64_t, 64> Record;
   BitstreamReader::BlockInfo *CurBlockInfo = 0;

   // Read all the records for this module.
   while (1) {
     unsigned Code = ReadCode();
     if (Code == bitc::END_BLOCK)
       return ReadBlockEnd();
     if (Code == bitc::ENTER_SUBBLOCK) {
       ReadSubBlockID();
       if (SkipBlock()) return true;
       continue;
     }

     // Read abbrev records, associate them with CurBID.
     if (Code == bitc::DEFINE_ABBREV) {
       if (!CurBlockInfo) return true;
       ReadAbbrevRecord();

       // ReadAbbrevRecord installs the abbrev in CurAbbrevs.  Move it to the
       // appropriate BlockInfo.
       BitCodeAbbrev *Abbv = CurAbbrevs.back();
       CurAbbrevs.pop_back();
       CurBlockInfo->Abbrevs.push_back(Abbv);
       continue;
     }

     // Read a record.
     Record.clear();
     switch (ReadRecord(Code, Record)) {
       default: break;  // Default behavior, ignore unknown content.
       case bitc::BLOCKINFO_CODE_SETBID:
         if (Record.size() < 1) return true;
         CurBlockInfo = &BitStream->getOrCreateBlockInfo((unsigned)Record[0]);
         break;
       case bitc::BLOCKINFO_CODE_BLOCKNAME: {
         if (!CurBlockInfo) return true;
         if (BitStream->isIgnoringBlockInfoNames()) break;  // Ignore name.
         std::string Name;
         for (unsigned i = 0, e = Record.size(); i != e; ++i)
           Name += (char)Record[i];
         CurBlockInfo->Name = Name;
         break;
       }
       case bitc::BLOCKINFO_CODE_SETRECORDNAME: {
         if (!CurBlockInfo) return true;
         if (BitStream->isIgnoringBlockInfoNames()) break;  // Ignore name.
         std::string Name;
         for (unsigned i = 1, e = Record.size(); i != e; ++i)
           Name += (char)Record[i];
         CurBlockInfo->RecordNames.push_back(std::make_pair((unsigned)Record[0],
                                                            Name));
         break;
       }
     }
   }
 }
	//===- BitstreamReader.cpp - BitstreamReader implementation ---------------===//
	//
	// The LLVM Compiler Infrastructure
	//
	// This file is distributed under the University of Illinois Open Source
	// License. See LICENSE.TXT for details.
	//
	//===----------------------------------------------------------------------===//

	#include "llvm/Bitcode/BitstreamReader.h"

	using namespace llvm;

	//===----------------------------------------------------------------------===//
	// BitstreamCursor implementation
	//===----------------------------------------------------------------------===//

	void BitstreamCursor::operator=(const BitstreamCursor &RHS) {
	freeState();

	BitStream = RHS.BitStream;
	NextChar = RHS.NextChar;
	CurWord = RHS.CurWord;
	BitsInCurWord = RHS.BitsInCurWord;
	CurCodeSize = RHS.CurCodeSize;

	// Copy abbreviations, and bump ref counts.
	CurAbbrevs = RHS.CurAbbrevs;
	for (unsigned i = 0, e = static_cast<unsigned>(CurAbbrevs.size());
	i != e; ++i)
	CurAbbrevs[i]->addRef();

	// Copy block scope and bump ref counts.
	BlockScope = RHS.BlockScope;
	for (unsigned S = 0, e = static_cast<unsigned>(BlockScope.size());
	S != e; ++S) {
	std::vector<BitCodeAbbrev*> &Abbrevs = BlockScope[S].PrevAbbrevs;
	for (unsigned i = 0, e = static_cast<unsigned>(Abbrevs.size());
	i != e; ++i)
	Abbrevs[i]->addRef();
	}
	}

	void BitstreamCursor::freeState() {
	// Free all the Abbrevs.
	for (unsigned i = 0, e = static_cast<unsigned>(CurAbbrevs.size());
	i != e; ++i)
	CurAbbrevs[i]->dropRef();
	CurAbbrevs.clear();

	// Free all the Abbrevs in the block scope.
	for (unsigned S = 0, e = static_cast<unsigned>(BlockScope.size());
	S != e; ++S) {
	std::vector<BitCodeAbbrev*> &Abbrevs = BlockScope[S].PrevAbbrevs;
	for (unsigned i = 0, e = static_cast<unsigned>(Abbrevs.size());
	i != e; ++i)
	Abbrevs[i]->dropRef();
	}
	BlockScope.clear();
	}

	/// EnterSubBlock - Having read the ENTER_SUBBLOCK abbrevid, enter
	/// the block, and return true if the block has an error.
	bool BitstreamCursor::EnterSubBlock(unsigned BlockID, unsigned *NumWordsP) {
	// Save the current block's state on BlockScope.
	BlockScope.push_back(Block(CurCodeSize));
	BlockScope.back().PrevAbbrevs.swap(CurAbbrevs);

	// Add the abbrevs specific to this block to the CurAbbrevs list.
	if (const BitstreamReader::BlockInfo *Info =
	BitStream->getBlockInfo(BlockID)) {
	for (unsigned i = 0, e = static_cast<unsigned>(Info->Abbrevs.size());
	i != e; ++i) {
	CurAbbrevs.push_back(Info->Abbrevs[i]);
	CurAbbrevs.back()->addRef();
	}
	}

	// Get the codesize of this block.
	CurCodeSize = ReadVBR(bitc::CodeLenWidth);
	SkipToWord();
	unsigned NumWords = Read(bitc::BlockSizeWidth);
	if (NumWordsP) *NumWordsP = NumWords;

	// Validate that this block is sane.
	if (CurCodeSize == 0 \|\| AtEndOfStream())
	return true;

	return false;
	}


	unsigned BitstreamCursor::ReadRecord(unsigned AbbrevID,
	SmallVectorImpl<uint64_t> &Vals,
	const char *BlobStart, unsigned BlobLen){
	if (AbbrevID == bitc::UNABBREV_RECORD) {
	unsigned Code = ReadVBR(6);
	unsigned NumElts = ReadVBR(6);
	for (unsigned i = 0; i != NumElts; ++i)
	Vals.push_back(ReadVBR64(6));
	return Code;
	}

	const BitCodeAbbrev *Abbv = getAbbrev(AbbrevID);

	for (unsigned i = 0, e = Abbv->getNumOperandInfos(); i != e; ++i) {
	const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);
	if (Op.isLiteral()) {
	ReadAbbreviatedLiteral(Op, Vals);
	continue;
	}

	if (Op.getEncoding() != BitCodeAbbrevOp::Array &&
	Op.getEncoding() != BitCodeAbbrevOp::Blob) {
	ReadAbbreviatedField(Op, Vals);
	continue;
	}

	if (Op.getEncoding() == BitCodeAbbrevOp::Array) {
	// Array case. Read the number of elements as a vbr6.
	unsigned NumElts = ReadVBR(6);

	// Get the element encoding.
	assert(i+2 == e && "array op not second to last?");
	const BitCodeAbbrevOp &EltEnc = Abbv->getOperandInfo(++i);

	// Read all the elements.
	for (; NumElts; --NumElts)
	ReadAbbreviatedField(EltEnc, Vals);
	continue;
	}

	assert(Op.getEncoding() == BitCodeAbbrevOp::Blob);
	// Blob case. Read the number of bytes as a vbr6.
	unsigned NumElts = ReadVBR(6);
	SkipToWord(); // 32-bit alignment

	// Figure out where the end of this blob will be including tail padding.
	size_t NewEnd = NextChar+((NumElts+3)&~3);

	// If this would read off the end of the bitcode file, just set the
	// record to empty and return.
	if (!canSkipToPos(NewEnd)) {
	Vals.append(NumElts, 0);
	NextChar = BitStream->getBitcodeBytes().getExtent();
	break;
	}

	// Otherwise, read the number of bytes. If we can return a reference to
	// the data, do so to avoid copying it.
	if (BlobStart) {
	BlobStart = (const char)BitStream->getBitcodeBytes().getPointer(
	NextChar, NumElts);
	*BlobLen = NumElts;
	} else {
	for (; NumElts; ++NextChar, --NumElts)
	Vals.push_back(getByte(NextChar));
	}
	// Skip over tail padding.
	NextChar = NewEnd;
	}

	unsigned Code = (unsigned)Vals[0];
	Vals.erase(Vals.begin());
	return Code;
	}


	void BitstreamCursor::ReadAbbrevRecord() {
	BitCodeAbbrev *Abbv = new BitCodeAbbrev();
	unsigned NumOpInfo = ReadVBR(5);
	for (unsigned i = 0; i != NumOpInfo; ++i) {
	bool IsLiteral = Read(1) ? true : false;
	if (IsLiteral) {
	Abbv->Add(BitCodeAbbrevOp(ReadVBR64(8)));
	continue;
	}

	BitCodeAbbrevOp::Encoding E = (BitCodeAbbrevOp::Encoding)Read(3);
	if (BitCodeAbbrevOp::hasEncodingData(E))
	Abbv->Add(BitCodeAbbrevOp(E, ReadVBR64(5)));
	else
	Abbv->Add(BitCodeAbbrevOp(E));
	}
	CurAbbrevs.push_back(Abbv);
	}

	bool BitstreamCursor::ReadBlockInfoBlock() {
	// If this is the second stream to get to the block info block, skip it.
	if (BitStream->hasBlockInfoRecords())
	return SkipBlock();

	if (EnterSubBlock(bitc::BLOCKINFO_BLOCK_ID)) return true;

	SmallVector<uint64_t, 64> Record;
	BitstreamReader::BlockInfo *CurBlockInfo = 0;

	// Read all the records for this module.
	while (1) {
	unsigned Code = ReadCode();
	if (Code == bitc::END_BLOCK)
	return ReadBlockEnd();
	if (Code == bitc::ENTER_SUBBLOCK) {
	ReadSubBlockID();
	if (SkipBlock()) return true;
	continue;
	}

	// Read abbrev records, associate them with CurBID.
	if (Code == bitc::DEFINE_ABBREV) {
	if (!CurBlockInfo) return true;
	ReadAbbrevRecord();

	// ReadAbbrevRecord installs the abbrev in CurAbbrevs. Move it to the
	// appropriate BlockInfo.
	BitCodeAbbrev *Abbv = CurAbbrevs.back();
	CurAbbrevs.pop_back();
	CurBlockInfo->Abbrevs.push_back(Abbv);
	continue;
	}

	// Read a record.
	Record.clear();
	switch (ReadRecord(Code, Record)) {
	default: break; // Default behavior, ignore unknown content.
	case bitc::BLOCKINFO_CODE_SETBID:
	if (Record.size() < 1) return true;
	CurBlockInfo = &BitStream->getOrCreateBlockInfo((unsigned)Record[0]);
	break;
	case bitc::BLOCKINFO_CODE_BLOCKNAME: {
	if (!CurBlockInfo) return true;
	if (BitStream->isIgnoringBlockInfoNames()) break; // Ignore name.
	std::string Name;
	for (unsigned i = 0, e = Record.size(); i != e; ++i)
	Name += (char)Record[i];
	CurBlockInfo->Name = Name;
	break;
	}
	case bitc::BLOCKINFO_CODE_SETRECORDNAME: {
	if (!CurBlockInfo) return true;
	if (BitStream->isIgnoringBlockInfoNames()) break; // Ignore name.
	std::string Name;
	for (unsigned i = 1, e = Record.size(); i != e; ++i)
	Name += (char)Record[i];
	CurBlockInfo->RecordNames.push_back(std::make_pair((unsigned)Record[0],
	Name));
	break;
	}
	}
	}
	}