[Bitcode] Move Bitstream to a separate library

This moves Bitcode/Bitstream*, Bitcode/BitCodes.h to Bitstream/.

This is needed to avoid a circular dependency when using the bitstream
code for parsing optimization remarks.

Since Bitcode uses Core for the IR part:

libLLVMRemarks -> Bitcode -> Core

and Core uses libLLVMRemarks to generate remarks (see
IR/RemarkStreamer.cpp):

Core -> libLLVMRemarks

we need to separate the Bitstream and Bitcode part.

For clang-doc, it seems that it doesn't need the whole bitcode layer, so
I updated the CMake to only use the bitstream part.

Differential Revision: https://reviews.llvm.org/D63899

llvm-svn: 365091

1 files changed, 0 insertions, 510 deletions

diff --git a/llvm/lib/Bitcode/Reader/BitstreamReader.cpp b/llvm/lib/Bitcode/Reader/BitstreamReader.cpp
deleted file mode 100644
index 2f29ce29db0..00000000000
--- a/llvm/lib/Bitcode/Reader/BitstreamReader.cpp
+++ /dev/null
@@ -1,510 +0,0 @@
-//===- BitstreamReader.cpp - BitstreamReader implementation ---------------===//
-//
-// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
-// See https://llvm.org/LICENSE.txt for license information.
-// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
-//
-//===----------------------------------------------------------------------===//
-
-#include "llvm/Bitcode/BitstreamReader.h"
-#include "llvm/ADT/StringRef.h"
-#include <cassert>
-#include <string>
-
-using namespace llvm;
-
-//===----------------------------------------------------------------------===//
-//  BitstreamCursor implementation
-//===----------------------------------------------------------------------===//
-
-/// Having read the ENTER_SUBBLOCK abbrevid, enter the block.
-Error 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 (BlockInfo) {
-    if (const BitstreamBlockInfo::BlockInfo *Info =
-            BlockInfo->getBlockInfo(BlockID)) {
-      CurAbbrevs.insert(CurAbbrevs.end(), Info->Abbrevs.begin(),
-                        Info->Abbrevs.end());
-    }
-  }
-
-  // Get the codesize of this block.
-  Expected<uint32_t> MaybeVBR = ReadVBR(bitc::CodeLenWidth);
-  if (!MaybeVBR)
-    return MaybeVBR.takeError();
-  CurCodeSize = MaybeVBR.get();
-
-  if (CurCodeSize > MaxChunkSize)
-    return llvm::createStringError(
-        std::errc::illegal_byte_sequence,
-        "can't read more than %zu at a time, trying to read %u", +MaxChunkSize,
-        CurCodeSize);
-
-  SkipToFourByteBoundary();
-  Expected<word_t> MaybeNum = Read(bitc::BlockSizeWidth);
-  if (!MaybeNum)
-    return MaybeNum.takeError();
-  word_t NumWords = MaybeNum.get();
-  if (NumWordsP)
-    *NumWordsP = NumWords;
-
-  if (CurCodeSize == 0)
-    return llvm::createStringError(
-        std::errc::illegal_byte_sequence,
-        "can't enter sub-block: current code size is 0");
-  if (AtEndOfStream())
-    return llvm::createStringError(
-        std::errc::illegal_byte_sequence,
-        "can't enter sub block: already at end of stream");
-
-  return Error::success();
-}
-
-static Expected<uint64_t> readAbbreviatedField(BitstreamCursor &Cursor,
-                                               const BitCodeAbbrevOp &Op) {
-  assert(!Op.isLiteral() && "Not to be used with literals!");
-
-  // Decode the value as we are commanded.
-  switch (Op.getEncoding()) {
-  case BitCodeAbbrevOp::Array:
-  case BitCodeAbbrevOp::Blob:
-    llvm_unreachable("Should not reach here");
-  case BitCodeAbbrevOp::Fixed:
-    assert((unsigned)Op.getEncodingData() <= Cursor.MaxChunkSize);
-    return Cursor.Read((unsigned)Op.getEncodingData());
-  case BitCodeAbbrevOp::VBR:
-    assert((unsigned)Op.getEncodingData() <= Cursor.MaxChunkSize);
-    return Cursor.ReadVBR64((unsigned)Op.getEncodingData());
-  case BitCodeAbbrevOp::Char6:
-    if (Expected<unsigned> Res = Cursor.Read(6))
-      return BitCodeAbbrevOp::DecodeChar6(Res.get());
-    else
-      return Res.takeError();
-  }
-  llvm_unreachable("invalid abbreviation encoding");
-}
-
-static Error skipAbbreviatedField(BitstreamCursor &Cursor,
-                                  const BitCodeAbbrevOp &Op) {
-  assert(!Op.isLiteral() && "Not to be used with literals!");
-
-  // Decode the value as we are commanded.
-  switch (Op.getEncoding()) {
-  case BitCodeAbbrevOp::Array:
-  case BitCodeAbbrevOp::Blob:
-    llvm_unreachable("Should not reach here");
-  case BitCodeAbbrevOp::Fixed:
-    assert((unsigned)Op.getEncodingData() <= Cursor.MaxChunkSize);
-    if (Expected<unsigned> Res = Cursor.Read((unsigned)Op.getEncodingData()))
-      break;
-    else
-      return Res.takeError();
-  case BitCodeAbbrevOp::VBR:
-    assert((unsigned)Op.getEncodingData() <= Cursor.MaxChunkSize);
-    if (Expected<uint64_t> Res =
-            Cursor.ReadVBR64((unsigned)Op.getEncodingData()))
-      break;
-    else
-      return Res.takeError();
-  case BitCodeAbbrevOp::Char6:
-    if (Expected<unsigned> Res = Cursor.Read(6))
-      break;
-    else
-      return Res.takeError();
-  }
-  return ErrorSuccess();
-}
-
-/// skipRecord - Read the current record and discard it.
-Expected<unsigned> BitstreamCursor::skipRecord(unsigned AbbrevID) {
-  // Skip unabbreviated records by reading past their entries.
-  if (AbbrevID == bitc::UNABBREV_RECORD) {
-    Expected<uint32_t> MaybeCode = ReadVBR(6);
-    if (!MaybeCode)
-      return MaybeCode.takeError();
-    unsigned Code = MaybeCode.get();
-    Expected<uint32_t> MaybeVBR = ReadVBR(6);
-    if (!MaybeVBR)
-      return MaybeVBR.get();
-    unsigned NumElts = MaybeVBR.get();
-    for (unsigned i = 0; i != NumElts; ++i)
-      if (Expected<uint64_t> Res = ReadVBR64(6))
-        ; // Skip!
-      else
-        return Res.takeError();
-    return Code;
-  }
-
-  const BitCodeAbbrev *Abbv = getAbbrev(AbbrevID);
-  const BitCodeAbbrevOp &CodeOp = Abbv->getOperandInfo(0);
-  unsigned Code;
-  if (CodeOp.isLiteral())
-    Code = CodeOp.getLiteralValue();
-  else {
-    if (CodeOp.getEncoding() == BitCodeAbbrevOp::Array ||
-        CodeOp.getEncoding() == BitCodeAbbrevOp::Blob)
-      return llvm::createStringError(
-          std::errc::illegal_byte_sequence,
-          "Abbreviation starts with an Array or a Blob");
-    Expected<uint64_t> MaybeCode = readAbbreviatedField(*this, CodeOp);
-    if (!MaybeCode)
-      return MaybeCode.takeError();
-    Code = MaybeCode.get();
-  }
-
-  for (unsigned i = 1, e = Abbv->getNumOperandInfos(); i < e; ++i) {
-    const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);
-    if (Op.isLiteral())
-      continue;
-
-    if (Op.getEncoding() != BitCodeAbbrevOp::Array &&
-        Op.getEncoding() != BitCodeAbbrevOp::Blob) {
-      if (Error Err = skipAbbreviatedField(*this, Op))
-        return std::move(Err);
-      continue;
-    }
-
-    if (Op.getEncoding() == BitCodeAbbrevOp::Array) {
-      // Array case.  Read the number of elements as a vbr6.
-      Expected<uint32_t> MaybeNum = ReadVBR(6);
-      if (!MaybeNum)
-        return MaybeNum.takeError();
-      unsigned NumElts = MaybeNum.get();
-
-      // Get the element encoding.
-      assert(i+2 == e && "array op not second to last?");
-      const BitCodeAbbrevOp &EltEnc = Abbv->getOperandInfo(++i);
-
-      // Read all the elements.
-      // Decode the value as we are commanded.
-      switch (EltEnc.getEncoding()) {
-      default:
-        report_fatal_error("Array element type can't be an Array or a Blob");
-      case BitCodeAbbrevOp::Fixed:
-        assert((unsigned)EltEnc.getEncodingData() <= MaxChunkSize);
-        if (Error Err = JumpToBit(GetCurrentBitNo() +
-                                  NumElts * EltEnc.getEncodingData()))
-          return std::move(Err);
-        break;
-      case BitCodeAbbrevOp::VBR:
-        assert((unsigned)EltEnc.getEncodingData() <= MaxChunkSize);
-        for (; NumElts; --NumElts)
-          if (Expected<uint64_t> Res =
-                  ReadVBR64((unsigned)EltEnc.getEncodingData()))
-            ; // Skip!
-          else
-            return Res.takeError();
-        break;
-      case BitCodeAbbrevOp::Char6:
-        if (Error Err = JumpToBit(GetCurrentBitNo() + NumElts * 6))
-          return std::move(Err);
-        break;
-      }
-      continue;
-    }
-
-    assert(Op.getEncoding() == BitCodeAbbrevOp::Blob);
-    // Blob case.  Read the number of bytes as a vbr6.
-    Expected<uint32_t> MaybeNum = ReadVBR(6);
-    if (!MaybeNum)
-      return MaybeNum.takeError();
-    unsigned NumElts = MaybeNum.get();
-    SkipToFourByteBoundary();  // 32-bit alignment
-
-    // Figure out where the end of this blob will be including tail padding.
-    size_t NewEnd = GetCurrentBitNo()+((NumElts+3)&~3)*8;
-
-    // If this would read off the end of the bitcode file, just set the
-    // record to empty and return.
-    if (!canSkipToPos(NewEnd/8)) {
-      skipToEnd();
-      break;
-    }
-
-    // Skip over the blob.
-    if (Error Err = JumpToBit(NewEnd))
-      return std::move(Err);
-  }
-  return Code;
-}
-
-Expected<unsigned> BitstreamCursor::readRecord(unsigned AbbrevID,
-                                               SmallVectorImpl<uint64_t> &Vals,
-                                               StringRef *Blob) {
-  if (AbbrevID == bitc::UNABBREV_RECORD) {
-    Expected<uint32_t> MaybeCode = ReadVBR(6);
-    if (!MaybeCode)
-      return MaybeCode.takeError();
-    uint32_t Code = MaybeCode.get();
-    Expected<uint32_t> MaybeNumElts = ReadVBR(6);
-    if (!MaybeNumElts)
-      return MaybeNumElts.takeError();
-    uint32_t NumElts = MaybeNumElts.get();
-
-    for (unsigned i = 0; i != NumElts; ++i)
-      if (Expected<uint64_t> MaybeVal = ReadVBR64(6))
-        Vals.push_back(MaybeVal.get());
-      else
-        return MaybeVal.takeError();
-    return Code;
-  }
-
-  const BitCodeAbbrev *Abbv = getAbbrev(AbbrevID);
-
-  // Read the record code first.
-  assert(Abbv->getNumOperandInfos() != 0 && "no record code in abbreviation?");
-  const BitCodeAbbrevOp &CodeOp = Abbv->getOperandInfo(0);
-  unsigned Code;
-  if (CodeOp.isLiteral())
-    Code = CodeOp.getLiteralValue();
-  else {
-    if (CodeOp.getEncoding() == BitCodeAbbrevOp::Array ||
-        CodeOp.getEncoding() == BitCodeAbbrevOp::Blob)
-      report_fatal_error("Abbreviation starts with an Array or a Blob");
-    if (Expected<uint64_t> MaybeCode = readAbbreviatedField(*this, CodeOp))
-      Code = MaybeCode.get();
-    else
-      return MaybeCode.takeError();
-  }
-
-  for (unsigned i = 1, e = Abbv->getNumOperandInfos(); i != e; ++i) {
-    const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);
-    if (Op.isLiteral()) {
-      Vals.push_back(Op.getLiteralValue());
-      continue;
-    }
-
-    if (Op.getEncoding() != BitCodeAbbrevOp::Array &&
-        Op.getEncoding() != BitCodeAbbrevOp::Blob) {
-      if (Expected<uint64_t> MaybeVal = readAbbreviatedField(*this, Op))
-        Vals.push_back(MaybeVal.get());
-      else
-        return MaybeVal.takeError();
-      continue;
-    }
-
-    if (Op.getEncoding() == BitCodeAbbrevOp::Array) {
-      // Array case.  Read the number of elements as a vbr6.
-      Expected<uint32_t> MaybeNumElts = ReadVBR(6);
-      if (!MaybeNumElts)
-        return MaybeNumElts.takeError();
-      uint32_t NumElts = MaybeNumElts.get();
-
-      // Get the element encoding.
-      if (i + 2 != e)
-        report_fatal_error("Array op not second to last");
-      const BitCodeAbbrevOp &EltEnc = Abbv->getOperandInfo(++i);
-      if (!EltEnc.isEncoding())
-        report_fatal_error(
-            "Array element type has to be an encoding of a type");
-
-      // Read all the elements.
-      switch (EltEnc.getEncoding()) {
-      default:
-        report_fatal_error("Array element type can't be an Array or a Blob");
-      case BitCodeAbbrevOp::Fixed:
-        for (; NumElts; --NumElts)
-          if (Expected<SimpleBitstreamCursor::word_t> MaybeVal =
-                  Read((unsigned)EltEnc.getEncodingData()))
-            Vals.push_back(MaybeVal.get());
-          else
-            return MaybeVal.takeError();
-        break;
-      case BitCodeAbbrevOp::VBR:
-        for (; NumElts; --NumElts)
-          if (Expected<uint64_t> MaybeVal =
-                  ReadVBR64((unsigned)EltEnc.getEncodingData()))
-            Vals.push_back(MaybeVal.get());
-          else
-            return MaybeVal.takeError();
-        break;
-      case BitCodeAbbrevOp::Char6:
-        for (; NumElts; --NumElts)
-          if (Expected<SimpleBitstreamCursor::word_t> MaybeVal = Read(6))
-            Vals.push_back(BitCodeAbbrevOp::DecodeChar6(MaybeVal.get()));
-          else
-            return MaybeVal.takeError();
-      }
-      continue;
-    }
-
-    assert(Op.getEncoding() == BitCodeAbbrevOp::Blob);
-    // Blob case.  Read the number of bytes as a vbr6.
-    Expected<uint32_t> MaybeNumElts = ReadVBR(6);
-    if (!MaybeNumElts)
-      return MaybeNumElts.takeError();
-    uint32_t NumElts = MaybeNumElts.get();
-    SkipToFourByteBoundary();  // 32-bit alignment
-
-    // Figure out where the end of this blob will be including tail padding.
-    size_t CurBitPos = GetCurrentBitNo();
-    size_t NewEnd = CurBitPos+((NumElts+3)&~3)*8;
-
-    // If this would read off the end of the bitcode file, just set the
-    // record to empty and return.
-    if (!canSkipToPos(NewEnd/8)) {
-      Vals.append(NumElts, 0);
-      skipToEnd();
-      break;
-    }
-
-    // Otherwise, inform the streamer that we need these bytes in memory.  Skip
-    // over tail padding first, in case jumping to NewEnd invalidates the Blob
-    // pointer.
-    if (Error Err = JumpToBit(NewEnd))
-      return std::move(Err);
-    const char *Ptr = (const char *)getPointerToBit(CurBitPos, NumElts);
-
-    // If we can return a reference to the data, do so to avoid copying it.
-    if (Blob) {
-      *Blob = StringRef(Ptr, NumElts);
-    } else {
-      // Otherwise, unpack into Vals with zero extension.
-      for (; NumElts; --NumElts)
-        Vals.push_back((unsigned char)*Ptr++);
-    }
-  }
-
-  return Code;
-}
-
-Error BitstreamCursor::ReadAbbrevRecord() {
-  auto Abbv = std::make_shared<BitCodeAbbrev>();
-  Expected<uint32_t> MaybeNumOpInfo = ReadVBR(5);
-  if (!MaybeNumOpInfo)
-    return MaybeNumOpInfo.takeError();
-  unsigned NumOpInfo = MaybeNumOpInfo.get();
-  for (unsigned i = 0; i != NumOpInfo; ++i) {
-    Expected<word_t> MaybeIsLiteral = Read(1);
-    if (!MaybeIsLiteral)
-      return MaybeIsLiteral.takeError();
-    bool IsLiteral = MaybeIsLiteral.get();
-    if (IsLiteral) {
-      Expected<uint64_t> MaybeOp = ReadVBR64(8);
-      if (!MaybeOp)
-        return MaybeOp.takeError();
-      Abbv->Add(BitCodeAbbrevOp(MaybeOp.get()));
-      continue;
-    }
-
-    Expected<word_t> MaybeEncoding = Read(3);
-    if (!MaybeEncoding)
-      return MaybeEncoding.takeError();
-    BitCodeAbbrevOp::Encoding E =
-        (BitCodeAbbrevOp::Encoding)MaybeEncoding.get();
-    if (BitCodeAbbrevOp::hasEncodingData(E)) {
-      Expected<uint64_t> MaybeData = ReadVBR64(5);
-      if (!MaybeData)
-        return MaybeData.takeError();
-      uint64_t Data = MaybeData.get();
-
-      // As a special case, handle fixed(0) (i.e., a fixed field with zero bits)
-      // and vbr(0) as a literal zero.  This is decoded the same way, and avoids
-      // a slow path in Read() to have to handle reading zero bits.
-      if ((E == BitCodeAbbrevOp::Fixed || E == BitCodeAbbrevOp::VBR) &&
-          Data == 0) {
-        Abbv->Add(BitCodeAbbrevOp(0));
-        continue;
-      }
-
-      if ((E == BitCodeAbbrevOp::Fixed || E == BitCodeAbbrevOp::VBR) &&
-          Data > MaxChunkSize)
-        report_fatal_error(
-            "Fixed or VBR abbrev record with size > MaxChunkData");
-
-      Abbv->Add(BitCodeAbbrevOp(E, Data));
-    } else
-      Abbv->Add(BitCodeAbbrevOp(E));
-  }
-
-  if (Abbv->getNumOperandInfos() == 0)
-    report_fatal_error("Abbrev record with no operands");
-  CurAbbrevs.push_back(std::move(Abbv));
-
-  return Error::success();
-}
-
-Expected<Optional<BitstreamBlockInfo>>
-BitstreamCursor::ReadBlockInfoBlock(bool ReadBlockInfoNames) {
-  if (llvm::Error Err = EnterSubBlock(bitc::BLOCKINFO_BLOCK_ID))
-    return std::move(Err);
-
-  BitstreamBlockInfo NewBlockInfo;
-
-  SmallVector<uint64_t, 64> Record;
-  BitstreamBlockInfo::BlockInfo *CurBlockInfo = nullptr;
-
-  // Read all the records for this module.
-  while (true) {
-    Expected<BitstreamEntry> MaybeEntry =
-        advanceSkippingSubblocks(AF_DontAutoprocessAbbrevs);
-    if (!MaybeEntry)
-      return MaybeEntry.takeError();
-    BitstreamEntry Entry = MaybeEntry.get();
-
-    switch (Entry.Kind) {
-    case llvm::BitstreamEntry::SubBlock: // Handled for us already.
-    case llvm::BitstreamEntry::Error:
-      return None;
-    case llvm::BitstreamEntry::EndBlock:
-      return std::move(NewBlockInfo);
-    case llvm::BitstreamEntry::Record:
-      // The interesting case.
-      break;
-    }
-
-    // Read abbrev records, associate them with CurBID.
-    if (Entry.ID == bitc::DEFINE_ABBREV) {
-      if (!CurBlockInfo) return None;
-      if (Error Err = ReadAbbrevRecord())
-        return std::move(Err);
-
-      // ReadAbbrevRecord installs the abbrev in CurAbbrevs.  Move it to the
-      // appropriate BlockInfo.
-      CurBlockInfo->Abbrevs.push_back(std::move(CurAbbrevs.back()));
-      CurAbbrevs.pop_back();
-      continue;
-    }
-
-    // Read a record.
-    Record.clear();
-    Expected<unsigned> MaybeBlockInfo = readRecord(Entry.ID, Record);
-    if (!MaybeBlockInfo)
-      return MaybeBlockInfo.takeError();
-    switch (MaybeBlockInfo.get()) {
-    default:
-      break; // Default behavior, ignore unknown content.
-    case bitc::BLOCKINFO_CODE_SETBID:
-      if (Record.size() < 1)
-        return None;
-      CurBlockInfo = &NewBlockInfo.getOrCreateBlockInfo((unsigned)Record[0]);
-      break;
-    case bitc::BLOCKINFO_CODE_BLOCKNAME: {
-      if (!CurBlockInfo)
-        return None;
-      if (!ReadBlockInfoNames)
-        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 None;
-        if (!ReadBlockInfoNames)
-          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;
-      }
-      }
-  }
-}