[llvm-commits] CVS: llvm/include/llvm/Bitcode/BitCodes.h BitstreamReader.h BitstreamWriter.h ReaderWriter.h
Chris Lattner
sabre at nondot.org
Sat Apr 21 23:22:23 PDT 2007
Changes in directory llvm/include/llvm/Bitcode:
BitCodes.h added (r1.1)
BitstreamReader.h added (r1.1)
BitstreamWriter.h added (r1.1)
ReaderWriter.h added (r1.1)
---
Log message:
Define the content-independent interfaces to read/write bitcode files and
the high-level interface to read/write LLVM IR bitcode files.
This is a work in progress.
---
Diffs of the changes: (+523 -0)
BitCodes.h | 46 +++++++++++
BitstreamReader.h | 220 ++++++++++++++++++++++++++++++++++++++++++++++++++++++
BitstreamWriter.h | 219 +++++++++++++++++++++++++++++++++++++++++++++++++++++
ReaderWriter.h | 38 +++++++++
4 files changed, 523 insertions(+)
Index: llvm/include/llvm/Bitcode/BitCodes.h
diff -c /dev/null llvm/include/llvm/Bitcode/BitCodes.h:1.1
*** /dev/null Sun Apr 22 01:22:15 2007
--- llvm/include/llvm/Bitcode/BitCodes.h Sun Apr 22 01:22:05 2007
***************
*** 0 ****
--- 1,46 ----
+ //===- BitCodes.h - Enum values for the bitcode format ----------*- C++ -*-===//
+ //
+ // The LLVM Compiler Infrastructure
+ //
+ // This file was developed by Chris Lattner and is distributed under
+ // the University of Illinois Open Source License. See LICENSE.TXT for details.
+ //
+ //===----------------------------------------------------------------------===//
+ //
+ // This header Bitcode enum values.
+ //
+ // The enum values defined in this file should be considered permanent. If
+ // new features are added, they should have values added at the end of the
+ // respective lists.
+ //
+ //===----------------------------------------------------------------------===//
+
+ #ifndef LLVM_BITCODE_BITCODES_H
+ #define LLVM_BITCODE_BITCODES_H
+
+ namespace llvm {
+ namespace bitc {
+ enum StandardWidths {
+ BlockIDWidth = 8, // We use VBR-8 for block IDs.
+ CodeLenWidth = 4, // Codelen are VBR-4.
+ BlockSizeWidth = 32 // BlockSize up to 2^32 32-bit words = 32GB per block.
+ };
+
+ // The standard code namespace always has a way to exit a block, enter a
+ // nested block, define abbrevs, and define an unabbreviated record.
+ enum FixedCodes {
+ END_BLOCK = 0, // Must be zero to guarantee termination for broken bitcode.
+ ENTER_SUBBLOCK = 1,
+
+ // Two codes are reserved for defining abbrevs and for emitting an
+ // unabbreviated record.
+ DEFINE_ABBREVS = 2,
+ UNABBREV_RECORD = 3,
+
+ // This is not a code, this is a marker for the first abbrev assignment.
+ FIRST_ABBREV = 4
+ };
+ } // End bitc namespace
+ } // End llvm namespace
+
+ #endif
Index: llvm/include/llvm/Bitcode/BitstreamReader.h
diff -c /dev/null llvm/include/llvm/Bitcode/BitstreamReader.h:1.1
*** /dev/null Sun Apr 22 01:22:23 2007
--- llvm/include/llvm/Bitcode/BitstreamReader.h Sun Apr 22 01:22:05 2007
***************
*** 0 ****
--- 1,220 ----
+ //===- BitstreamReader.h - Low-level bitstream reader interface -*- C++ -*-===//
+ //
+ // The LLVM Compiler Infrastructure
+ //
+ // This file was developed by Chris Lattner and is distributed under
+ // the University of Illinois Open Source License. See LICENSE.TXT for details.
+ //
+ //===----------------------------------------------------------------------===//
+ //
+ // This header defines the BitstreamReader class. This class can be used to
+ // read an arbitrary bitstream, regardless of its contents.
+ //
+ //===----------------------------------------------------------------------===//
+
+ #ifndef BITSTREAM_READER_H
+ #define BITSTREAM_READER_H
+
+ #include "llvm/Bitcode/BitCodes.h"
+ #include "llvm/ADT/SmallVector.h"
+ #include <cassert>
+
+ namespace llvm {
+
+ class BitstreamReader {
+ const unsigned char *NextChar;
+ const unsigned char *LastChar;
+
+ /// CurWord - This is the current data we have pulled from the stream but have
+ /// not returned to the client.
+ uint32_t CurWord;
+
+ /// BitsInCurWord - This is the number of bits in CurWord that are valid. This
+ /// is always from [0...31] inclusive.
+ unsigned BitsInCurWord;
+
+ // CurCodeSize - This is the declared size of code values used for the current
+ // block, in bits.
+ unsigned CurCodeSize;
+
+ /// BlockScope - This tracks the codesize of parent blocks.
+ SmallVector<unsigned, 8> BlockScope;
+
+ public:
+ BitstreamReader(const unsigned char *Start, const unsigned char *End)
+ : NextChar(Start), LastChar(End) {
+ assert(((End-Start) & 3) == 0 &&"Bitcode stream not a multiple of 4 bytes");
+ CurWord = 0;
+ BitsInCurWord = 0;
+ CurCodeSize = 2;
+ }
+
+ bool AtEndOfStream() const { return NextChar == LastChar; }
+
+ uint32_t Read(unsigned NumBits) {
+ // If the field is fully contained by CurWord, return it quickly.
+ if (BitsInCurWord >= NumBits) {
+ uint32_t R = CurWord & ((1U << NumBits)-1);
+ CurWord >>= NumBits;
+ BitsInCurWord -= NumBits;
+ return R;
+ }
+
+ // If we run out of data, stop at the end of the stream.
+ if (LastChar == NextChar) {
+ CurWord = 0;
+ BitsInCurWord = 0;
+ return 0;
+ }
+
+ unsigned R = CurWord;
+
+ // Read the next word from the stream.
+ CurWord = (NextChar[0] << 0) | (NextChar[1] << 8) |
+ (NextChar[2] << 16) | (NextChar[3] << 24);
+ NextChar += 4;
+
+ // 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;
+
+ // BitsLeft bits have just been used up from CurWord.
+ if (BitsLeft != 32)
+ CurWord >>= BitsLeft;
+ else
+ CurWord = 0;
+ BitsInCurWord = 32-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) {
+ uint64_t Piece = Read(NumBits);
+ if ((Piece & (1U << NumBits-1)) == 0)
+ return Piece;
+
+ uint64_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);
+ }
+ }
+
+ void SkipToWord() {
+ BitsInCurWord = 0;
+ CurWord = 0;
+ }
+
+
+ unsigned ReadCode() {
+ return Read(CurCodeSize);
+ }
+
+ //===--------------------------------------------------------------------===//
+ // Block Manipulation
+ //===--------------------------------------------------------------------===//
+
+ // Block header:
+ // [ENTER_SUBBLOCK, blockid, newcodelen, <align4bytes>, blocklen]
+
+ /// ReadSubBlockID - Having read the ENTER_SUBBLOCK code, read the BlockID for
+ /// the block.
+ unsigned ReadSubBlockID() {
+ return ReadVBR(bitc::BlockIDWidth);
+ }
+
+ /// SkipBlock - Having read the ENTER_SUBBLOCK abbrevid and a BlockID, skip
+ /// over the body of this block. If the block record is malformed, return
+ /// true.
+ bool SkipBlock() {
+ // 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);
+
+ // Check that the block wasn't partially defined, and that the offset isn't
+ // bogus.
+ if (AtEndOfStream() || NextChar+NumWords*4 > LastChar)
+ return true;
+
+ NextChar += NumWords*4;
+ return false;
+ }
+
+ /// EnterSubBlock - Having read the ENTER_SUBBLOCK abbrevid, read and enter
+ /// the block, returning the BlockID of the block we just entered.
+ bool EnterSubBlock() {
+ BlockScope.push_back(CurCodeSize);
+
+ // Get the codesize of this block.
+ CurCodeSize = ReadVBR(bitc::CodeLenWidth);
+ SkipToWord();
+ unsigned NumWords = Read(bitc::BlockSizeWidth);
+
+ // Validate that this block is sane.
+ if (CurCodeSize == 0 || AtEndOfStream() || NextChar+NumWords*4 > LastChar)
+ return true;
+
+ return false;
+ }
+
+ bool ReadBlockEnd() {
+ if (BlockScope.empty()) return true;
+
+ // Block tail:
+ // [END_BLOCK, <align4bytes>]
+ SkipToWord();
+ CurCodeSize = BlockScope.back();
+ BlockScope.pop_back();
+ return false;
+ }
+
+ //===--------------------------------------------------------------------===//
+ // Record Processing
+ //===--------------------------------------------------------------------===//
+
+ unsigned ReadRecord(unsigned AbbrevID, SmallVectorImpl<uint64_t> &Vals) {
+ 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;
+ }
+
+ assert(0 && "Reading with abbrevs not implemented!");
+ }
+
+ };
+
+ } // End llvm namespace
+
+ #endif
+
+
\ No newline at end of file
Index: llvm/include/llvm/Bitcode/BitstreamWriter.h
diff -c /dev/null llvm/include/llvm/Bitcode/BitstreamWriter.h:1.1
*** /dev/null Sun Apr 22 01:22:23 2007
--- llvm/include/llvm/Bitcode/BitstreamWriter.h Sun Apr 22 01:22:05 2007
***************
*** 0 ****
--- 1,219 ----
+ //===- BitstreamWriter.h - Low-level bitstream writer interface -*- C++ -*-===//
+ //
+ // The LLVM Compiler Infrastructure
+ //
+ // This file was developed by Chris Lattner and is distributed under
+ // the University of Illinois Open Source License. See LICENSE.TXT for details.
+ //
+ //===----------------------------------------------------------------------===//
+ //
+ // This header defines the BitstreamWriter class. This class can be used to
+ // write an arbitrary bitstream, regardless of its contents.
+ //
+ //===----------------------------------------------------------------------===//
+
+ #ifndef BITSTREAM_WRITER_H
+ #define BITSTREAM_WRITER_H
+
+ #include "llvm/Bitcode/BitCodes.h"
+ #include "llvm/ADT/SmallVector.h"
+ #include <cassert>
+ #include <vector>
+
+ namespace llvm {
+
+ class BitstreamWriter {
+ std::vector<unsigned char> &Out;
+
+ /// CurBit - Always between 0 and 31 inclusive, specifies the next bit to use.
+ unsigned CurBit;
+
+ /// CurValue - The current value. Only bits < CurBit are valid.
+ uint32_t CurValue;
+
+ // CurCodeSize - This is the declared size of code values used for the current
+ // block, in bits.
+ unsigned CurCodeSize;
+
+ struct Block {
+ unsigned PrevCodeSize;
+ unsigned StartSizeWord;
+ Block(unsigned PCS, unsigned SSW) : PrevCodeSize(PCS), StartSizeWord(SSW) {}
+ };
+
+ /// BlockScope - This tracks the current blocks that we have entered.
+ std::vector<Block> BlockScope;
+ public:
+ BitstreamWriter(std::vector<unsigned char> &O)
+ : Out(O), CurBit(0), CurValue(0), CurCodeSize(2) {}
+
+ ~BitstreamWriter() {
+ assert(CurBit == 0 && "Unflused data remaining");
+ assert(BlockScope.empty() && "Block imbalance");
+ }
+ //===--------------------------------------------------------------------===//
+ // Basic Primitives for emitting bits to the stream.
+ //===--------------------------------------------------------------------===//
+
+ void Emit(uint32_t Val, unsigned NumBits) {
+ assert(NumBits <= 32 && "Invalid value size!");
+ assert((Val & ~(~0U >> (32-NumBits))) == 0 && "High bits set!");
+ CurValue |= Val << CurBit;
+ if (CurBit + NumBits < 32) {
+ CurBit += NumBits;
+ return;
+ }
+
+ // Add the current word.
+ unsigned V = CurValue;
+ Out.push_back((unsigned char)(V >> 0));
+ Out.push_back((unsigned char)(V >> 8));
+ Out.push_back((unsigned char)(V >> 16));
+ Out.push_back((unsigned char)(V >> 24));
+
+ if (CurBit)
+ CurValue = Val >> 32-CurBit;
+ else
+ CurValue = 0;
+ CurBit = (CurBit+NumBits) & 31;
+ }
+
+ void Emit64(uint64_t Val, unsigned NumBits) {
+ if (NumBits <= 32)
+ Emit((uint32_t)Val, NumBits);
+ else {
+ Emit((uint32_t)Val, 32);
+ Emit((uint32_t)(Val >> 32), NumBits-32);
+ }
+ }
+
+ void FlushToWord() {
+ if (CurBit) {
+ unsigned V = CurValue;
+ Out.push_back((unsigned char)(V >> 0));
+ Out.push_back((unsigned char)(V >> 8));
+ Out.push_back((unsigned char)(V >> 16));
+ Out.push_back((unsigned char)(V >> 24));
+ CurBit = 0;
+ CurValue = 0;
+ }
+ }
+
+ void EmitVBR(uint32_t Val, unsigned NumBits) {
+ uint32_t Threshold = 1U << (NumBits-1);
+
+ // Emit the bits with VBR encoding, NumBits-1 bits at a time.
+ while (Val >= Threshold) {
+ Emit((Val & ((1 << (NumBits-1))-1)) | (1 << (NumBits-1)), NumBits);
+ Val >>= NumBits-1;
+ }
+
+ Emit(Val, NumBits);
+ }
+
+ void EmitVBR64(uint64_t Val, unsigned NumBits) {
+ if ((uint32_t)Val == Val)
+ return EmitVBR((uint32_t)Val, NumBits);
+
+ uint64_t Threshold = 1U << (NumBits-1);
+
+ // Emit the bits with VBR encoding, NumBits-1 bits at a time.
+ while (Val >= Threshold) {
+ Emit(((uint32_t)Val & ((1 << (NumBits-1))-1)) |
+ (1 << (NumBits-1)), NumBits);
+ Val >>= NumBits-1;
+ }
+
+ Emit((uint32_t)Val, NumBits);
+ }
+
+ /// EmitCode - Emit the specified code.
+ void EmitCode(unsigned Val) {
+ Emit(Val, CurCodeSize);
+ }
+
+ //===--------------------------------------------------------------------===//
+ // Block Manipulation
+ //===--------------------------------------------------------------------===//
+
+ void EnterSubblock(unsigned BlockID, unsigned CodeLen) {
+ // Block header:
+ // [ENTER_SUBBLOCK, blockid, newcodelen, <align4bytes>, blocklen]
+ EmitCode(bitc::ENTER_SUBBLOCK);
+ EmitVBR(BlockID, bitc::BlockIDWidth);
+ EmitVBR(CodeLen, bitc::CodeLenWidth);
+ FlushToWord();
+ BlockScope.push_back(Block(CurCodeSize, Out.size()/4));
+ // Emit a placeholder, which will be replaced when the block is popped.
+ Emit(0, bitc::BlockSizeWidth);
+
+ CurCodeSize = CodeLen;
+ }
+
+ void ExitBlock() {
+ assert(!BlockScope.empty() && "Block scope imbalance!");
+ Block B = BlockScope.back();
+ BlockScope.pop_back();
+
+ // Block tail:
+ // [END_BLOCK, <align4bytes>]
+ EmitCode(bitc::END_BLOCK);
+ FlushToWord();
+
+ // Compute the size of the block, in words, not counting the size field.
+ unsigned SizeInWords = Out.size()/4-B.StartSizeWord - 1;
+ unsigned ByteNo = B.StartSizeWord*4;
+
+ // Update the block size field in the header of this sub-block.
+ Out[ByteNo++] = (unsigned char)(SizeInWords >> 0);
+ Out[ByteNo++] = (unsigned char)(SizeInWords >> 8);
+ Out[ByteNo++] = (unsigned char)(SizeInWords >> 16);
+ Out[ByteNo++] = (unsigned char)(SizeInWords >> 24);
+
+ // Restore the outer block's code size.
+ CurCodeSize = B.PrevCodeSize;
+ }
+
+ //===--------------------------------------------------------------------===//
+ // Record Emission
+ //===--------------------------------------------------------------------===//
+
+ /// EmitRecord - Emit the specified record to the stream, using an abbrev if
+ /// we have one to compress the output.
+ void EmitRecord(unsigned Code, SmallVectorImpl<uint64_t> &Vals,
+ unsigned Abbrev = 0) {
+ if (Abbrev) {
+ assert(0 && "abbrevs not implemented yet!");
+ } else {
+ // If we don't have an abbrev to use, emit this in its fully unabbreviated
+ // form.
+ EmitCode(bitc::UNABBREV_RECORD);
+ EmitVBR(Code, 6);
+ EmitVBR(Vals.size(), 6);
+ for (unsigned i = 0, e = Vals.size(); i != e; ++i)
+ EmitVBR64(Vals[i], 6);
+ }
+ }
+
+ /// EmitRecord - Emit the specified record to the stream, using an abbrev if
+ /// we have one to compress the output.
+ void EmitRecord(unsigned Code, SmallVectorImpl<unsigned> &Vals,
+ unsigned Abbrev = 0) {
+ if (Abbrev) {
+ assert(0 && "abbrevs not implemented yet!");
+ } else {
+ // If we don't have an abbrev to use, emit this in its fully unabbreviated
+ // form.
+ EmitCode(bitc::UNABBREV_RECORD);
+ EmitVBR(Code, 6);
+ EmitVBR(Vals.size(), 6);
+ for (unsigned i = 0, e = Vals.size(); i != e; ++i)
+ EmitVBR(Vals[i], 6);
+ }
+ }
+ };
+
+
+ } // End llvm namespace
+
+ #endif
Index: llvm/include/llvm/Bitcode/ReaderWriter.h
diff -c /dev/null llvm/include/llvm/Bitcode/ReaderWriter.h:1.1
*** /dev/null Sun Apr 22 01:22:23 2007
--- llvm/include/llvm/Bitcode/ReaderWriter.h Sun Apr 22 01:22:05 2007
***************
*** 0 ****
--- 1,38 ----
+ //===-- llvm/Bitcode/ReaderWriter.h - Bitcode reader/writers ----*- C++ -*-===//
+ //
+ // The LLVM Compiler Infrastructure
+ //
+ // This file was developed by Chris Lattner and is distributed under
+ // the University of Illinois Open Source License. See LICENSE.TXT for details.
+ //
+ //===----------------------------------------------------------------------===//
+ //
+ // This header defines interfaces to read and write LLVM bitcode files/streams.
+ //
+ //===----------------------------------------------------------------------===//
+
+ #ifndef LLVM_BITCODE_H
+ #define LLVM_BITCODE_H
+
+ #include <iosfwd>
+ #include <string>
+
+ namespace llvm {
+ class Module;
+ class ModuleProvider;
+
+ ModuleProvider *getBitcodeModuleProvider(const std::string &Filename,
+ std::string *ErrMsg = 0);
+
+
+ /// ParseBitcodeFile - Read the specified bitcode file, returning the module.
+ /// If an error occurs, return null and fill in *ErrMsg if non-null.
+ Module *ParseBitcodeFile(const std::string &Filename,
+ std::string *ErrMsg = 0);
+
+ /// WriteBitcodeToFile - Write the specified module to the specified output
+ /// stream.
+ void WriteBitcodeToFile(const Module *M, std::ostream &Out);
+ } // End llvm namespace
+
+ #endif
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