--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/include/llvm/Bitcode/BitstreamWriter.h	Thu Dec 12 13:56:28 2013 +0900
@@ -0,0 +1,549 @@
+//===- BitstreamWriter.h - Low-level bitstream writer interface -*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file 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 LLVM_BITCODE_BITSTREAMWRITER_H
+#define LLVM_BITCODE_BITSTREAMWRITER_H
+
+#include "llvm/ADT/SmallVector.h"
+#include "llvm/ADT/StringRef.h"
+#include "llvm/Bitcode/BitCodes.h"
+#include <vector>
+
+namespace llvm {
+
+class BitstreamWriter {
+  SmallVectorImpl<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;
+
+  /// BlockInfoCurBID - When emitting a BLOCKINFO_BLOCK, this is the currently
+  /// selected BLOCK ID.
+  unsigned BlockInfoCurBID;
+
+  /// CurAbbrevs - Abbrevs installed at in this block.
+  std::vector<BitCodeAbbrev*> CurAbbrevs;
+
+  struct Block {
+    unsigned PrevCodeSize;
+    unsigned StartSizeWord;
+    std::vector<BitCodeAbbrev*> PrevAbbrevs;
+    Block(unsigned PCS, unsigned SSW) : PrevCodeSize(PCS), StartSizeWord(SSW) {}
+  };
+
+  /// BlockScope - This tracks the current blocks that we have entered.
+  std::vector<Block> BlockScope;
+
+  /// BlockInfo - This contains information emitted to BLOCKINFO_BLOCK blocks.
+  /// These describe abbreviations that all blocks of the specified ID inherit.
+  struct BlockInfo {
+    unsigned BlockID;
+    std::vector<BitCodeAbbrev*> Abbrevs;
+  };
+  std::vector<BlockInfo> BlockInfoRecords;
+
+  // BackpatchWord - Backpatch a 32-bit word in the output with the specified
+  // value.
+  void BackpatchWord(unsigned ByteNo, unsigned NewWord) {
+    Out[ByteNo++] = (unsigned char)(NewWord >>  0);
+    Out[ByteNo++] = (unsigned char)(NewWord >>  8);
+    Out[ByteNo++] = (unsigned char)(NewWord >> 16);
+    Out[ByteNo  ] = (unsigned char)(NewWord >> 24);
+  }
+
+  void WriteByte(unsigned char Value) {
+    Out.push_back(Value);
+  }
+
+  void WriteWord(unsigned Value) {
+    unsigned char Bytes[4] = {
+      (unsigned char)(Value >>  0),
+      (unsigned char)(Value >>  8),
+      (unsigned char)(Value >> 16),
+      (unsigned char)(Value >> 24) };
+    Out.append(&Bytes[0], &Bytes[4]);
+  }
+
+  unsigned GetBufferOffset() const {
+    return Out.size();
+  }
+
+  unsigned GetWordIndex() const {
+    unsigned Offset = GetBufferOffset();
+    assert((Offset & 3) == 0 && "Not 32-bit aligned");
+    return Offset / 4;
+  }
+
+public:
+  explicit BitstreamWriter(SmallVectorImpl<char> &O)
+    : Out(O), CurBit(0), CurValue(0), CurCodeSize(2) {}
+
+  ~BitstreamWriter() {
+    assert(CurBit == 0 && "Unflused data remaining");
+    assert(BlockScope.empty() && CurAbbrevs.empty() && "Block imbalance");
+
+    // Free the BlockInfoRecords.
+    while (!BlockInfoRecords.empty()) {
+      BlockInfo &Info = BlockInfoRecords.back();
+      // Free blockinfo abbrev info.
+      for (unsigned i = 0, e = static_cast<unsigned>(Info.Abbrevs.size());
+           i != e; ++i)
+        Info.Abbrevs[i]->dropRef();
+      BlockInfoRecords.pop_back();
+    }
+  }
+
+  /// \brief Retrieve the current position in the stream, in bits.
+  uint64_t GetCurrentBitNo() const { return GetBufferOffset() * 8 + CurBit; }
+
+  //===--------------------------------------------------------------------===//
+  // Basic Primitives for emitting bits to the stream.
+  //===--------------------------------------------------------------------===//
+
+  void Emit(uint32_t Val, unsigned NumBits) {
+    assert(NumBits && 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.
+    WriteWord(CurValue);
+
+    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) {
+      WriteWord(CurValue);
+      CurBit = 0;
+      CurValue = 0;
+    }
+  }
+
+  void EmitVBR(uint32_t Val, unsigned NumBits) {
+    assert(NumBits <= 32 && "Too many bits to emit!");
+    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) {
+    assert(NumBits <= 32 && "Too many bits to emit!");
+    if ((uint32_t)Val == Val)
+      return EmitVBR((uint32_t)Val, NumBits);
+
+    uint32_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
+  //===--------------------------------------------------------------------===//
+
+  /// getBlockInfo - If there is block info for the specified ID, return it,
+  /// otherwise return null.
+  BlockInfo *getBlockInfo(unsigned BlockID) {
+    // Common case, the most recent entry matches BlockID.
+    if (!BlockInfoRecords.empty() && BlockInfoRecords.back().BlockID == BlockID)
+      return &BlockInfoRecords.back();
+
+    for (unsigned i = 0, e = static_cast<unsigned>(BlockInfoRecords.size());
+         i != e; ++i)
+      if (BlockInfoRecords[i].BlockID == BlockID)
+        return &BlockInfoRecords[i];
+    return 0;
+  }
+
+  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();
+
+    unsigned BlockSizeWordIndex = GetWordIndex();
+    unsigned OldCodeSize = CurCodeSize;
+
+    // Emit a placeholder, which will be replaced when the block is popped.
+    Emit(0, bitc::BlockSizeWidth);
+
+    CurCodeSize = CodeLen;
+
+    // Push the outer block's abbrev set onto the stack, start out with an
+    // empty abbrev set.
+    BlockScope.push_back(Block(OldCodeSize, BlockSizeWordIndex));
+    BlockScope.back().PrevAbbrevs.swap(CurAbbrevs);
+
+    // If there is a blockinfo for this BlockID, add all the predefined abbrevs
+    // to the abbrev list.
+    if (BlockInfo *Info = getBlockInfo(BlockID)) {
+      for (unsigned i = 0, e = static_cast<unsigned>(Info->Abbrevs.size());
+           i != e; ++i) {
+        CurAbbrevs.push_back(Info->Abbrevs[i]);
+        Info->Abbrevs[i]->addRef();
+      }
+    }
+  }
+
+  void ExitBlock() {
+    assert(!BlockScope.empty() && "Block scope imbalance!");
+
+    // Delete all abbrevs.
+    for (unsigned i = 0, e = static_cast<unsigned>(CurAbbrevs.size());
+         i != e; ++i)
+      CurAbbrevs[i]->dropRef();
+
+    const Block &B = BlockScope.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 = GetWordIndex() - B.StartSizeWord - 1;
+    unsigned ByteNo = B.StartSizeWord*4;
+
+    // Update the block size field in the header of this sub-block.
+    BackpatchWord(ByteNo, SizeInWords);
+
+    // Restore the inner block's code size and abbrev table.
+    CurCodeSize = B.PrevCodeSize;
+    BlockScope.back().PrevAbbrevs.swap(CurAbbrevs);
+    BlockScope.pop_back();
+  }
+
+  //===--------------------------------------------------------------------===//
+  // Record Emission
+  //===--------------------------------------------------------------------===//
+
+private:
+  /// EmitAbbreviatedLiteral - Emit a literal value according to its abbrev
+  /// record.  This is a no-op, since the abbrev specifies the literal to use.
+  template<typename uintty>
+  void EmitAbbreviatedLiteral(const BitCodeAbbrevOp &Op, uintty V) {
+    assert(Op.isLiteral() && "Not a literal");
+    // If the abbrev specifies the literal value to use, don't emit
+    // anything.
+    assert(V == Op.getLiteralValue() &&
+           "Invalid abbrev for record!");
+  }
+
+  /// EmitAbbreviatedField - Emit a single scalar field value with the specified
+  /// encoding.
+  template<typename uintty>
+  void EmitAbbreviatedField(const BitCodeAbbrevOp &Op, uintty V) {
+    assert(!Op.isLiteral() && "Literals should use EmitAbbreviatedLiteral!");
+
+    // Encode the value as we are commanded.
+    switch (Op.getEncoding()) {
+    default: llvm_unreachable("Unknown encoding!");
+    case BitCodeAbbrevOp::Fixed:
+      if (Op.getEncodingData())
+        Emit((unsigned)V, (unsigned)Op.getEncodingData());
+      break;
+    case BitCodeAbbrevOp::VBR:
+      if (Op.getEncodingData())
+        EmitVBR64(V, (unsigned)Op.getEncodingData());
+      break;
+    case BitCodeAbbrevOp::Char6:
+      Emit(BitCodeAbbrevOp::EncodeChar6((char)V), 6);
+      break;
+    }
+  }
+
+  /// EmitRecordWithAbbrevImpl - This is the core implementation of the record
+  /// emission code.  If BlobData is non-null, then it specifies an array of
+  /// data that should be emitted as part of the Blob or Array operand that is
+  /// known to exist at the end of the record.
+  template<typename uintty>
+  void EmitRecordWithAbbrevImpl(unsigned Abbrev, SmallVectorImpl<uintty> &Vals,
+                                StringRef Blob) {
+    const char *BlobData = Blob.data();
+    unsigned BlobLen = (unsigned) Blob.size();
+    unsigned AbbrevNo = Abbrev-bitc::FIRST_APPLICATION_ABBREV;
+    assert(AbbrevNo < CurAbbrevs.size() && "Invalid abbrev #!");
+    BitCodeAbbrev *Abbv = CurAbbrevs[AbbrevNo];
+
+    EmitCode(Abbrev);
+
+    unsigned RecordIdx = 0;
+    for (unsigned i = 0, e = static_cast<unsigned>(Abbv->getNumOperandInfos());
+         i != e; ++i) {
+      const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);
+      if (Op.isLiteral()) {
+        assert(RecordIdx < Vals.size() && "Invalid abbrev/record");
+        EmitAbbreviatedLiteral(Op, Vals[RecordIdx]);
+        ++RecordIdx;
+      } else if (Op.getEncoding() == BitCodeAbbrevOp::Array) {
+        // Array case.
+        assert(i+2 == e && "array op not second to last?");
+        const BitCodeAbbrevOp &EltEnc = Abbv->getOperandInfo(++i);
+
+        // If this record has blob data, emit it, otherwise we must have record
+        // entries to encode this way.
+        if (BlobData) {
+          assert(RecordIdx == Vals.size() &&
+                 "Blob data and record entries specified for array!");
+          // Emit a vbr6 to indicate the number of elements present.
+          EmitVBR(static_cast<uint32_t>(BlobLen), 6);
+
+          // Emit each field.
+          for (unsigned i = 0; i != BlobLen; ++i)
+            EmitAbbreviatedField(EltEnc, (unsigned char)BlobData[i]);
+
+          // Know that blob data is consumed for assertion below.
+          BlobData = 0;
+        } else {
+          // Emit a vbr6 to indicate the number of elements present.
+          EmitVBR(static_cast<uint32_t>(Vals.size()-RecordIdx), 6);
+
+          // Emit each field.
+          for (unsigned e = Vals.size(); RecordIdx != e; ++RecordIdx)
+            EmitAbbreviatedField(EltEnc, Vals[RecordIdx]);
+        }
+      } else if (Op.getEncoding() == BitCodeAbbrevOp::Blob) {
+        // If this record has blob data, emit it, otherwise we must have record
+        // entries to encode this way.
+
+        // Emit a vbr6 to indicate the number of elements present.
+        if (BlobData) {
+          EmitVBR(static_cast<uint32_t>(BlobLen), 6);
+          assert(RecordIdx == Vals.size() &&
+                 "Blob data and record entries specified for blob operand!");
+        } else {
+          EmitVBR(static_cast<uint32_t>(Vals.size()-RecordIdx), 6);
+        }
+
+        // Flush to a 32-bit alignment boundary.
+        FlushToWord();
+
+        // Emit each field as a literal byte.
+        if (BlobData) {
+          for (unsigned i = 0; i != BlobLen; ++i)
+            WriteByte((unsigned char)BlobData[i]);
+
+          // Know that blob data is consumed for assertion below.
+          BlobData = 0;
+        } else {
+          for (unsigned e = Vals.size(); RecordIdx != e; ++RecordIdx) {
+            assert(isUInt<8>(Vals[RecordIdx]) &&
+                   "Value too large to emit as blob");
+            WriteByte((unsigned char)Vals[RecordIdx]);
+          }
+        }
+
+        // Align end to 32-bits.
+        while (GetBufferOffset() & 3)
+          WriteByte(0);
+      } else {  // Single scalar field.
+        assert(RecordIdx < Vals.size() && "Invalid abbrev/record");
+        EmitAbbreviatedField(Op, Vals[RecordIdx]);
+        ++RecordIdx;
+      }
+    }
+    assert(RecordIdx == Vals.size() && "Not all record operands emitted!");
+    assert(BlobData == 0 &&
+           "Blob data specified for record that doesn't use it!");
+  }
+
+public:
+
+  /// EmitRecord - Emit the specified record to the stream, using an abbrev if
+  /// we have one to compress the output.
+  template<typename uintty>
+  void EmitRecord(unsigned Code, SmallVectorImpl<uintty> &Vals,
+                  unsigned Abbrev = 0) {
+    if (!Abbrev) {
+      // If we don't have an abbrev to use, emit this in its fully unabbreviated
+      // form.
+      EmitCode(bitc::UNABBREV_RECORD);
+      EmitVBR(Code, 6);
+      EmitVBR(static_cast<uint32_t>(Vals.size()), 6);
+      for (unsigned i = 0, e = static_cast<unsigned>(Vals.size()); i != e; ++i)
+        EmitVBR64(Vals[i], 6);
+      return;
+    }
+
+    // Insert the code into Vals to treat it uniformly.
+    Vals.insert(Vals.begin(), Code);
+
+    EmitRecordWithAbbrev(Abbrev, Vals);
+  }
+
+  /// EmitRecordWithAbbrev - Emit a record with the specified abbreviation.
+  /// Unlike EmitRecord, the code for the record should be included in Vals as
+  /// the first entry.
+  template<typename uintty>
+  void EmitRecordWithAbbrev(unsigned Abbrev, SmallVectorImpl<uintty> &Vals) {
+    EmitRecordWithAbbrevImpl(Abbrev, Vals, StringRef());
+  }
+
+  /// EmitRecordWithBlob - Emit the specified record to the stream, using an
+  /// abbrev that includes a blob at the end.  The blob data to emit is
+  /// specified by the pointer and length specified at the end.  In contrast to
+  /// EmitRecord, this routine expects that the first entry in Vals is the code
+  /// of the record.
+  template<typename uintty>
+  void EmitRecordWithBlob(unsigned Abbrev, SmallVectorImpl<uintty> &Vals,
+                          StringRef Blob) {
+    EmitRecordWithAbbrevImpl(Abbrev, Vals, Blob);
+  }
+  template<typename uintty>
+  void EmitRecordWithBlob(unsigned Abbrev, SmallVectorImpl<uintty> &Vals,
+                          const char *BlobData, unsigned BlobLen) {
+    return EmitRecordWithAbbrevImpl(Abbrev, Vals, StringRef(BlobData, BlobLen));
+  }
+
+  /// EmitRecordWithArray - Just like EmitRecordWithBlob, works with records
+  /// that end with an array.
+  template<typename uintty>
+  void EmitRecordWithArray(unsigned Abbrev, SmallVectorImpl<uintty> &Vals,
+                          StringRef Array) {
+    EmitRecordWithAbbrevImpl(Abbrev, Vals, Array);
+  }
+  template<typename uintty>
+  void EmitRecordWithArray(unsigned Abbrev, SmallVectorImpl<uintty> &Vals,
+                          const char *ArrayData, unsigned ArrayLen) {
+    return EmitRecordWithAbbrevImpl(Abbrev, Vals, StringRef(ArrayData,
+                                                            ArrayLen));
+  }
+
+  //===--------------------------------------------------------------------===//
+  // Abbrev Emission
+  //===--------------------------------------------------------------------===//
+
+private:
+  // Emit the abbreviation as a DEFINE_ABBREV record.
+  void EncodeAbbrev(BitCodeAbbrev *Abbv) {
+    EmitCode(bitc::DEFINE_ABBREV);
+    EmitVBR(Abbv->getNumOperandInfos(), 5);
+    for (unsigned i = 0, e = static_cast<unsigned>(Abbv->getNumOperandInfos());
+         i != e; ++i) {
+      const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);
+      Emit(Op.isLiteral(), 1);
+      if (Op.isLiteral()) {
+        EmitVBR64(Op.getLiteralValue(), 8);
+      } else {
+        Emit(Op.getEncoding(), 3);
+        if (Op.hasEncodingData())
+          EmitVBR64(Op.getEncodingData(), 5);
+      }
+    }
+  }
+public:
+
+  /// EmitAbbrev - This emits an abbreviation to the stream.  Note that this
+  /// method takes ownership of the specified abbrev.
+  unsigned EmitAbbrev(BitCodeAbbrev *Abbv) {
+    // Emit the abbreviation as a record.
+    EncodeAbbrev(Abbv);
+    CurAbbrevs.push_back(Abbv);
+    return static_cast<unsigned>(CurAbbrevs.size())-1 +
+      bitc::FIRST_APPLICATION_ABBREV;
+  }
+
+  //===--------------------------------------------------------------------===//
+  // BlockInfo Block Emission
+  //===--------------------------------------------------------------------===//
+
+  /// EnterBlockInfoBlock - Start emitting the BLOCKINFO_BLOCK.
+  void EnterBlockInfoBlock(unsigned CodeWidth) {
+    EnterSubblock(bitc::BLOCKINFO_BLOCK_ID, CodeWidth);
+    BlockInfoCurBID = ~0U;
+  }
+private:
+  /// SwitchToBlockID - If we aren't already talking about the specified block
+  /// ID, emit a BLOCKINFO_CODE_SETBID record.
+  void SwitchToBlockID(unsigned BlockID) {
+    if (BlockInfoCurBID == BlockID) return;
+    SmallVector<unsigned, 2> V;
+    V.push_back(BlockID);
+    EmitRecord(bitc::BLOCKINFO_CODE_SETBID, V);
+    BlockInfoCurBID = BlockID;
+  }
+
+  BlockInfo &getOrCreateBlockInfo(unsigned BlockID) {
+    if (BlockInfo *BI = getBlockInfo(BlockID))
+      return *BI;
+
+    // Otherwise, add a new record.
+    BlockInfoRecords.push_back(BlockInfo());
+    BlockInfoRecords.back().BlockID = BlockID;
+    return BlockInfoRecords.back();
+  }
+
+public:
+
+  /// EmitBlockInfoAbbrev - Emit a DEFINE_ABBREV record for the specified
+  /// BlockID.
+  unsigned EmitBlockInfoAbbrev(unsigned BlockID, BitCodeAbbrev *Abbv) {
+    SwitchToBlockID(BlockID);
+    EncodeAbbrev(Abbv);
+
+    // Add the abbrev to the specified block record.
+    BlockInfo &Info = getOrCreateBlockInfo(BlockID);
+    Info.Abbrevs.push_back(Abbv);
+
+    return Info.Abbrevs.size()-1+bitc::FIRST_APPLICATION_ABBREV;
+  }
+};
+
+
+} // End llvm namespace
+
+#endif