text: //===-- llvm-bcanalyzer.cpp - Bitcode Analyzer --------------------------===//
  //
  // 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
  //
  //===----------------------------------------------------------------------===//
  //
  // This tool may be invoked in the following manner:
  //  llvm-bcanalyzer [options]      - Read LLVM bitcode from stdin
  //  llvm-bcanalyzer [options] x.bc - Read LLVM bitcode from the x.bc file
  //
  //  Options:
  //      --help      - Output information about command line switches
  //      --dump      - Dump low-level bitcode structure in readable format
  //
  // This tool provides analytical information about a bitcode file. It is
  // intended as an aid to developers of bitcode reading and writing software. It
  // produces on std::out a summary of the bitcode file that shows various
  // statistics about the contents of the file. By default this information is
  // detailed and contains information about individual bitcode blocks and the
  // functions in the module.
  // The tool is also able to print a bitcode file in a straight forward text
  // format that shows the containment and relationships of the information in
  // the bitcode file (-dump option).
  //
  //===----------------------------------------------------------------------===//
  
  #include "llvm/ADT/StringExtras.h"
  #include "llvm/Bitcode/BitcodeReader.h"
  #include "llvm/Bitcode/BitstreamReader.h"
  #include "llvm/Bitcode/LLVMBitCodes.h"
  #include "llvm/Support/CommandLine.h"
  #include "llvm/Support/Format.h"
  #include "llvm/Support/InitLLVM.h"
  #include "llvm/Support/ManagedStatic.h"
  #include "llvm/Support/MemoryBuffer.h"
  #include "llvm/Support/SHA1.h"
  #include "llvm/Support/WithColor.h"
  #include "llvm/Support/raw_ostream.h"
  using namespace llvm;
  
  static cl::opt<std::string>
    InputFilename(cl::Positional, cl::desc("<input bitcode>"), cl::init("-"));
  
  static cl::opt<bool> Dump("dump", cl::desc("Dump low level bitcode trace"));
  
  //===----------------------------------------------------------------------===//
  // Bitcode specific analysis.
  //===----------------------------------------------------------------------===//
  
  static cl::opt<bool> NoHistogram("disable-histogram",
                                   cl::desc("Do not print per-code histogram"));
  
  static cl::opt<bool>
  NonSymbolic("non-symbolic",
              cl::desc("Emit numeric info in dump even if"
                       " symbolic info is available"));
  
  static cl::opt<std::string>
    BlockInfoFilename("block-info",
                      cl::desc("Use the BLOCK_INFO from the given file"));
  
  static cl::opt<bool>
    ShowBinaryBlobs("show-binary-blobs",
                    cl::desc("Print binary blobs using hex escapes"));
  
  static cl::opt<std::string> CheckHash(
      "check-hash",
      cl::desc("Check module hash using the argument as a string table"));
  
  namespace {
  
  /// CurStreamTypeType - A type for CurStreamType
  enum CurStreamTypeType {
    UnknownBitstream,
    LLVMIRBitstream,
    ClangSerializedASTBitstream,
    ClangSerializedDiagnosticsBitstream,
  };
  
  }
  
  /// GetBlockName - Return a symbolic block name if known, otherwise return
  /// null.
  static const char *GetBlockName(unsigned BlockID,
                                  const BitstreamBlockInfo &BlockInfo,
                                  CurStreamTypeType CurStreamType) {
    // Standard blocks for all bitcode files.
    if (BlockID < bitc::FIRST_APPLICATION_BLOCKID) {
      if (BlockID == bitc::BLOCKINFO_BLOCK_ID)
        return "BLOCKINFO_BLOCK";
      return nullptr;
    }
  
    // Check to see if we have a blockinfo record for this block, with a name.
    if (const BitstreamBlockInfo::BlockInfo *Info =
            BlockInfo.getBlockInfo(BlockID)) {
      if (!Info->Name.empty())
        return Info->Name.c_str();
    }
  
  
    if (CurStreamType != LLVMIRBitstream) return nullptr;
  
    switch (BlockID) {
    default:                                 return nullptr;
    case bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID: return "OPERAND_BUNDLE_TAGS_BLOCK";
    case bitc::MODULE_BLOCK_ID:              return "MODULE_BLOCK";
    case bitc::PARAMATTR_BLOCK_ID:           return "PARAMATTR_BLOCK";
    case bitc::PARAMATTR_GROUP_BLOCK_ID:     return "PARAMATTR_GROUP_BLOCK_ID";
    case bitc::TYPE_BLOCK_ID_NEW:            return "TYPE_BLOCK_ID";
    case bitc::CONSTANTS_BLOCK_ID:           return "CONSTANTS_BLOCK";
    case bitc::FUNCTION_BLOCK_ID:            return "FUNCTION_BLOCK";
    case bitc::IDENTIFICATION_BLOCK_ID:
                                             return "IDENTIFICATION_BLOCK_ID";
    case bitc::VALUE_SYMTAB_BLOCK_ID:        return "VALUE_SYMTAB";
    case bitc::METADATA_BLOCK_ID:            return "METADATA_BLOCK";
    case bitc::METADATA_KIND_BLOCK_ID:       return "METADATA_KIND_BLOCK";
    case bitc::METADATA_ATTACHMENT_ID:       return "METADATA_ATTACHMENT_BLOCK";
    case bitc::USELIST_BLOCK_ID:             return "USELIST_BLOCK_ID";
    case bitc::GLOBALVAL_SUMMARY_BLOCK_ID:
                                             return "GLOBALVAL_SUMMARY_BLOCK";
    case bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID:
                                        return "FULL_LTO_GLOBALVAL_SUMMARY_BLOCK";
    case bitc::MODULE_STRTAB_BLOCK_ID:       return "MODULE_STRTAB_BLOCK";
    case bitc::STRTAB_BLOCK_ID:              return "STRTAB_BLOCK";
    case bitc::SYMTAB_BLOCK_ID:              return "SYMTAB_BLOCK";
    }
  }
  
  /// GetCodeName - Return a symbolic code name if known, otherwise return
  /// null.
  static const char *GetCodeName(unsigned CodeID, unsigned BlockID,
                                 const BitstreamBlockInfo &BlockInfo,
                                 CurStreamTypeType CurStreamType) {
    // Standard blocks for all bitcode files.
    if (BlockID < bitc::FIRST_APPLICATION_BLOCKID) {
      if (BlockID == bitc::BLOCKINFO_BLOCK_ID) {
        switch (CodeID) {
        default: return nullptr;
        case bitc::BLOCKINFO_CODE_SETBID:        return "SETBID";
        case bitc::BLOCKINFO_CODE_BLOCKNAME:     return "BLOCKNAME";
        case bitc::BLOCKINFO_CODE_SETRECORDNAME: return "SETRECORDNAME";
        }
      }
      return nullptr;
    }
  
    // Check to see if we have a blockinfo record for this record, with a name.
    if (const BitstreamBlockInfo::BlockInfo *Info =
          BlockInfo.getBlockInfo(BlockID)) {
      for (unsigned i = 0, e = Info->RecordNames.size(); i != e; ++i)
        if (Info->RecordNames[i].first == CodeID)
          return Info->RecordNames[i].second.c_str();
    }
  
  
    if (CurStreamType != LLVMIRBitstream) return nullptr;
  
  #define STRINGIFY_CODE(PREFIX, CODE)                                           \
    case bitc::PREFIX##_##CODE:                                                  \
      return #CODE;
    switch (BlockID) {
    default: return nullptr;
    case bitc::MODULE_BLOCK_ID:
      switch (CodeID) {
      default: return nullptr;
        STRINGIFY_CODE(MODULE_CODE, VERSION)
        STRINGIFY_CODE(MODULE_CODE, TRIPLE)
        STRINGIFY_CODE(MODULE_CODE, DATALAYOUT)
        STRINGIFY_CODE(MODULE_CODE, ASM)
        STRINGIFY_CODE(MODULE_CODE, SECTIONNAME)
        STRINGIFY_CODE(MODULE_CODE, DEPLIB) // FIXME: Remove in 4.0
        STRINGIFY_CODE(MODULE_CODE, GLOBALVAR)
        STRINGIFY_CODE(MODULE_CODE, FUNCTION)
        STRINGIFY_CODE(MODULE_CODE, ALIAS)
        STRINGIFY_CODE(MODULE_CODE, GCNAME)
        STRINGIFY_CODE(MODULE_CODE, VSTOFFSET)
        STRINGIFY_CODE(MODULE_CODE, METADATA_VALUES_UNUSED)
        STRINGIFY_CODE(MODULE_CODE, SOURCE_FILENAME)
        STRINGIFY_CODE(MODULE_CODE, HASH)
      }
    case bitc::IDENTIFICATION_BLOCK_ID:
      switch (CodeID) {
      default:
        return nullptr;
        STRINGIFY_CODE(IDENTIFICATION_CODE, STRING)
        STRINGIFY_CODE(IDENTIFICATION_CODE, EPOCH)
      }
    case bitc::PARAMATTR_BLOCK_ID:
      switch (CodeID) {
      default: return nullptr;
      // FIXME: Should these be different?
      case bitc::PARAMATTR_CODE_ENTRY_OLD: return "ENTRY";
      case bitc::PARAMATTR_CODE_ENTRY:     return "ENTRY";
      }
    case bitc::PARAMATTR_GROUP_BLOCK_ID:
      switch (CodeID) {
      default: return nullptr;
      case bitc::PARAMATTR_GRP_CODE_ENTRY: return "ENTRY";
      }
    case bitc::TYPE_BLOCK_ID_NEW:
      switch (CodeID) {
      default: return nullptr;
        STRINGIFY_CODE(TYPE_CODE, NUMENTRY)
        STRINGIFY_CODE(TYPE_CODE, VOID)
        STRINGIFY_CODE(TYPE_CODE, FLOAT)
        STRINGIFY_CODE(TYPE_CODE, DOUBLE)
        STRINGIFY_CODE(TYPE_CODE, LABEL)
        STRINGIFY_CODE(TYPE_CODE, OPAQUE)
        STRINGIFY_CODE(TYPE_CODE, INTEGER)
        STRINGIFY_CODE(TYPE_CODE, POINTER)
        STRINGIFY_CODE(TYPE_CODE, ARRAY)
        STRINGIFY_CODE(TYPE_CODE, VECTOR)
        STRINGIFY_CODE(TYPE_CODE, X86_FP80)
        STRINGIFY_CODE(TYPE_CODE, FP128)
        STRINGIFY_CODE(TYPE_CODE, PPC_FP128)
        STRINGIFY_CODE(TYPE_CODE, METADATA)
        STRINGIFY_CODE(TYPE_CODE, STRUCT_ANON)
        STRINGIFY_CODE(TYPE_CODE, STRUCT_NAME)
        STRINGIFY_CODE(TYPE_CODE, STRUCT_NAMED)
        STRINGIFY_CODE(TYPE_CODE, FUNCTION)
      }
  
    case bitc::CONSTANTS_BLOCK_ID:
      switch (CodeID) {
      default: return nullptr;
        STRINGIFY_CODE(CST_CODE, SETTYPE)
        STRINGIFY_CODE(CST_CODE, NULL)
        STRINGIFY_CODE(CST_CODE, UNDEF)
        STRINGIFY_CODE(CST_CODE, INTEGER)
        STRINGIFY_CODE(CST_CODE, WIDE_INTEGER)
        STRINGIFY_CODE(CST_CODE, FLOAT)
        STRINGIFY_CODE(CST_CODE, AGGREGATE)
        STRINGIFY_CODE(CST_CODE, STRING)
        STRINGIFY_CODE(CST_CODE, CSTRING)
        STRINGIFY_CODE(CST_CODE, CE_BINOP)
        STRINGIFY_CODE(CST_CODE, CE_CAST)
        STRINGIFY_CODE(CST_CODE, CE_GEP)
        STRINGIFY_CODE(CST_CODE, CE_INBOUNDS_GEP)
        STRINGIFY_CODE(CST_CODE, CE_SELECT)
        STRINGIFY_CODE(CST_CODE, CE_EXTRACTELT)
        STRINGIFY_CODE(CST_CODE, CE_INSERTELT)
        STRINGIFY_CODE(CST_CODE, CE_SHUFFLEVEC)
        STRINGIFY_CODE(CST_CODE, CE_CMP)
        STRINGIFY_CODE(CST_CODE, INLINEASM)
        STRINGIFY_CODE(CST_CODE, CE_SHUFVEC_EX)
        STRINGIFY_CODE(CST_CODE, CE_UNOP)
      case bitc::CST_CODE_BLOCKADDRESS:    return "CST_CODE_BLOCKADDRESS";
        STRINGIFY_CODE(CST_CODE, DATA)
      }
    case bitc::FUNCTION_BLOCK_ID:
      switch (CodeID) {
      default: return nullptr;
        STRINGIFY_CODE(FUNC_CODE, DECLAREBLOCKS)
        STRINGIFY_CODE(FUNC_CODE, INST_BINOP)
        STRINGIFY_CODE(FUNC_CODE, INST_CAST)
        STRINGIFY_CODE(FUNC_CODE, INST_GEP_OLD)
        STRINGIFY_CODE(FUNC_CODE, INST_INBOUNDS_GEP_OLD)
        STRINGIFY_CODE(FUNC_CODE, INST_SELECT)
        STRINGIFY_CODE(FUNC_CODE, INST_EXTRACTELT)
        STRINGIFY_CODE(FUNC_CODE, INST_INSERTELT)
        STRINGIFY_CODE(FUNC_CODE, INST_SHUFFLEVEC)
        STRINGIFY_CODE(FUNC_CODE, INST_CMP)
        STRINGIFY_CODE(FUNC_CODE, INST_RET)
        STRINGIFY_CODE(FUNC_CODE, INST_BR)
        STRINGIFY_CODE(FUNC_CODE, INST_SWITCH)
        STRINGIFY_CODE(FUNC_CODE, INST_INVOKE)
        STRINGIFY_CODE(FUNC_CODE, INST_UNOP)
        STRINGIFY_CODE(FUNC_CODE, INST_UNREACHABLE)
        STRINGIFY_CODE(FUNC_CODE, INST_CLEANUPRET)
        STRINGIFY_CODE(FUNC_CODE, INST_CATCHRET)
        STRINGIFY_CODE(FUNC_CODE, INST_CATCHPAD)
        STRINGIFY_CODE(FUNC_CODE, INST_PHI)
        STRINGIFY_CODE(FUNC_CODE, INST_ALLOCA)
        STRINGIFY_CODE(FUNC_CODE, INST_LOAD)
        STRINGIFY_CODE(FUNC_CODE, INST_VAARG)
        STRINGIFY_CODE(FUNC_CODE, INST_STORE)
        STRINGIFY_CODE(FUNC_CODE, INST_EXTRACTVAL)
        STRINGIFY_CODE(FUNC_CODE, INST_INSERTVAL)
        STRINGIFY_CODE(FUNC_CODE, INST_CMP2)
        STRINGIFY_CODE(FUNC_CODE, INST_VSELECT)
        STRINGIFY_CODE(FUNC_CODE, DEBUG_LOC_AGAIN)
        STRINGIFY_CODE(FUNC_CODE, INST_CALL)
        STRINGIFY_CODE(FUNC_CODE, DEBUG_LOC)
        STRINGIFY_CODE(FUNC_CODE, INST_GEP)
        STRINGIFY_CODE(FUNC_CODE, OPERAND_BUNDLE)
        STRINGIFY_CODE(FUNC_CODE, INST_FENCE)
        STRINGIFY_CODE(FUNC_CODE, INST_ATOMICRMW)
        STRINGIFY_CODE(FUNC_CODE, INST_LOADATOMIC)
        STRINGIFY_CODE(FUNC_CODE, INST_STOREATOMIC)
        STRINGIFY_CODE(FUNC_CODE, INST_CMPXCHG)
        STRINGIFY_CODE(FUNC_CODE, INST_CALLBR)
      }
    case bitc::VALUE_SYMTAB_BLOCK_ID:
      switch (CodeID) {
      default: return nullptr;
      STRINGIFY_CODE(VST_CODE, ENTRY)
      STRINGIFY_CODE(VST_CODE, BBENTRY)
      STRINGIFY_CODE(VST_CODE, FNENTRY)
      STRINGIFY_CODE(VST_CODE, COMBINED_ENTRY)
      }
    case bitc::MODULE_STRTAB_BLOCK_ID:
      switch (CodeID) {
      default:
        return nullptr;
        STRINGIFY_CODE(MST_CODE, ENTRY)
        STRINGIFY_CODE(MST_CODE, HASH)
      }
    case bitc::GLOBALVAL_SUMMARY_BLOCK_ID:
    case bitc::FULL_LTO_GLOBALVAL_SUMMARY_BLOCK_ID:
      switch (CodeID) {
      default:
        return nullptr;
        STRINGIFY_CODE(FS, PERMODULE)
        STRINGIFY_CODE(FS, PERMODULE_PROFILE)
        STRINGIFY_CODE(FS, PERMODULE_RELBF)
        STRINGIFY_CODE(FS, PERMODULE_GLOBALVAR_INIT_REFS)
        STRINGIFY_CODE(FS, COMBINED)
        STRINGIFY_CODE(FS, COMBINED_PROFILE)
        STRINGIFY_CODE(FS, COMBINED_GLOBALVAR_INIT_REFS)
        STRINGIFY_CODE(FS, ALIAS)
        STRINGIFY_CODE(FS, COMBINED_ALIAS)
        STRINGIFY_CODE(FS, COMBINED_ORIGINAL_NAME)
        STRINGIFY_CODE(FS, VERSION)
        STRINGIFY_CODE(FS, FLAGS)
        STRINGIFY_CODE(FS, TYPE_TESTS)
        STRINGIFY_CODE(FS, TYPE_TEST_ASSUME_VCALLS)
        STRINGIFY_CODE(FS, TYPE_CHECKED_LOAD_VCALLS)
        STRINGIFY_CODE(FS, TYPE_TEST_ASSUME_CONST_VCALL)
        STRINGIFY_CODE(FS, TYPE_CHECKED_LOAD_CONST_VCALL)
        STRINGIFY_CODE(FS, VALUE_GUID)
        STRINGIFY_CODE(FS, CFI_FUNCTION_DEFS)
        STRINGIFY_CODE(FS, CFI_FUNCTION_DECLS)
        STRINGIFY_CODE(FS, TYPE_ID)
      }
    case bitc::METADATA_ATTACHMENT_ID:
      switch(CodeID) {
      default:return nullptr;
        STRINGIFY_CODE(METADATA, ATTACHMENT)
      }
    case bitc::METADATA_BLOCK_ID:
      switch(CodeID) {
      default:return nullptr;
        STRINGIFY_CODE(METADATA, STRING_OLD)
        STRINGIFY_CODE(METADATA, VALUE)
        STRINGIFY_CODE(METADATA, NODE)
        STRINGIFY_CODE(METADATA, NAME)
        STRINGIFY_CODE(METADATA, DISTINCT_NODE)
        STRINGIFY_CODE(METADATA, KIND) // Older bitcode has it in a MODULE_BLOCK
        STRINGIFY_CODE(METADATA, LOCATION)
        STRINGIFY_CODE(METADATA, OLD_NODE)
        STRINGIFY_CODE(METADATA, OLD_FN_NODE)
        STRINGIFY_CODE(METADATA, NAMED_NODE)
        STRINGIFY_CODE(METADATA, GENERIC_DEBUG)
        STRINGIFY_CODE(METADATA, SUBRANGE)
        STRINGIFY_CODE(METADATA, ENUMERATOR)
        STRINGIFY_CODE(METADATA, BASIC_TYPE)
        STRINGIFY_CODE(METADATA, FILE)
        STRINGIFY_CODE(METADATA, DERIVED_TYPE)
        STRINGIFY_CODE(METADATA, COMPOSITE_TYPE)
        STRINGIFY_CODE(METADATA, SUBROUTINE_TYPE)
        STRINGIFY_CODE(METADATA, COMPILE_UNIT)
        STRINGIFY_CODE(METADATA, SUBPROGRAM)
        STRINGIFY_CODE(METADATA, LEXICAL_BLOCK)
        STRINGIFY_CODE(METADATA, LEXICAL_BLOCK_FILE)
        STRINGIFY_CODE(METADATA, NAMESPACE)
        STRINGIFY_CODE(METADATA, TEMPLATE_TYPE)
        STRINGIFY_CODE(METADATA, TEMPLATE_VALUE)
        STRINGIFY_CODE(METADATA, GLOBAL_VAR)
        STRINGIFY_CODE(METADATA, LOCAL_VAR)
        STRINGIFY_CODE(METADATA, EXPRESSION)
        STRINGIFY_CODE(METADATA, OBJC_PROPERTY)
        STRINGIFY_CODE(METADATA, IMPORTED_ENTITY)
        STRINGIFY_CODE(METADATA, MODULE)
        STRINGIFY_CODE(METADATA, MACRO)
        STRINGIFY_CODE(METADATA, MACRO_FILE)
        STRINGIFY_CODE(METADATA, STRINGS)
        STRINGIFY_CODE(METADATA, GLOBAL_DECL_ATTACHMENT)
        STRINGIFY_CODE(METADATA, GLOBAL_VAR_EXPR)
        STRINGIFY_CODE(METADATA, INDEX_OFFSET)
        STRINGIFY_CODE(METADATA, INDEX)
      }
    case bitc::METADATA_KIND_BLOCK_ID:
      switch (CodeID) {
      default:
        return nullptr;
        STRINGIFY_CODE(METADATA, KIND)
      }
    case bitc::USELIST_BLOCK_ID:
      switch(CodeID) {
      default:return nullptr;
      case bitc::USELIST_CODE_DEFAULT: return "USELIST_CODE_DEFAULT";
      case bitc::USELIST_CODE_BB:      return "USELIST_CODE_BB";
      }
  
    case bitc::OPERAND_BUNDLE_TAGS_BLOCK_ID:
      switch(CodeID) {
      default: return nullptr;
      case bitc::OPERAND_BUNDLE_TAG: return "OPERAND_BUNDLE_TAG";
      }
    case bitc::STRTAB_BLOCK_ID:
      switch(CodeID) {
      default: return nullptr;
      case bitc::STRTAB_BLOB: return "BLOB";
      }
    case bitc::SYMTAB_BLOCK_ID:
      switch(CodeID) {
      default: return nullptr;
      case bitc::SYMTAB_BLOB: return "BLOB";
      }
    }
  #undef STRINGIFY_CODE
  }
  
  struct PerRecordStats {
    unsigned NumInstances;
    unsigned NumAbbrev;
    uint64_t TotalBits;
  
    PerRecordStats() : NumInstances(0), NumAbbrev(0), TotalBits(0) {}
  };
  
  struct PerBlockIDStats {
    /// NumInstances - This the number of times this block ID has been seen.
    unsigned NumInstances;
  
    /// NumBits - The total size in bits of all of these blocks.
    uint64_t NumBits;
  
    /// NumSubBlocks - The total number of blocks these blocks contain.
    unsigned NumSubBlocks;
  
    /// NumAbbrevs - The total number of abbreviations.
    unsigned NumAbbrevs;
  
    /// NumRecords - The total number of records these blocks contain, and the
    /// number that are abbreviated.
    unsigned NumRecords, NumAbbreviatedRecords;
  
    /// CodeFreq - Keep track of the number of times we see each code.
    std::vector<PerRecordStats> CodeFreq;
  
    PerBlockIDStats()
      : NumInstances(0), NumBits(0),
        NumSubBlocks(0), NumAbbrevs(0), NumRecords(0), NumAbbreviatedRecords(0) {}
  };
  
  static std::map<unsigned, PerBlockIDStats> BlockIDStats;
  
  
  
  /// ReportError - All bitcode analysis errors go through this function, making this a
  /// good place to breakpoint if debugging.
  static bool ReportError(const Twine &Err) {
    WithColor::error() << Err << "\n";
    return true;
  }
  
  static bool decodeMetadataStringsBlob(StringRef Indent,
                                        ArrayRef<uint64_t> Record,
                                        StringRef Blob) {
    if (Blob.empty())
      return true;
  
    if (Record.size() != 2)
      return true;
  
    unsigned NumStrings = Record[0];
    unsigned StringsOffset = Record[1];
    outs() << " num-strings = " << NumStrings << " {\n";
  
    StringRef Lengths = Blob.slice(0, StringsOffset);
    SimpleBitstreamCursor R(Lengths);
    StringRef Strings = Blob.drop_front(StringsOffset);
    do {
      if (R.AtEndOfStream())
        return ReportError("bad length");
  
      unsigned Size = R.ReadVBR(6);
      if (Strings.size() < Size)
        return ReportError("truncated chars");
  
      outs() << Indent << "    '";
      outs().write_escaped(Strings.slice(0, Size), /*hex=*/true);
      outs() << "'\n";
      Strings = Strings.drop_front(Size);
    } while (--NumStrings);
  
    outs() << Indent << "  }";
    return false;
  }
  
  static bool decodeBlob(unsigned Code, unsigned BlockID, StringRef Indent,
                         ArrayRef<uint64_t> Record, StringRef Blob) {
    if (BlockID != bitc::METADATA_BLOCK_ID)
      return true;
    if (Code != bitc::METADATA_STRINGS)
      return true;
  
    return decodeMetadataStringsBlob(Indent, Record, Blob);
  }
  
  /// ParseBlock - Read a block, updating statistics, etc.
  static bool ParseBlock(BitstreamCursor &Stream, BitstreamBlockInfo &BlockInfo,
                         unsigned BlockID, unsigned IndentLevel,
                         CurStreamTypeType CurStreamType) {
    std::string Indent(IndentLevel*2, ' ');
    uint64_t BlockBitStart = Stream.GetCurrentBitNo();
  
    // Get the statistics for this BlockID.
    PerBlockIDStats &BlockStats = BlockIDStats[BlockID];
  
    BlockStats.NumInstances++;
  
    // BLOCKINFO is a special part of the stream.
    bool DumpRecords = Dump;
    if (BlockID == bitc::BLOCKINFO_BLOCK_ID) {
      if (Dump) outs() << Indent << "<BLOCKINFO_BLOCK/>\n";
      Optional<BitstreamBlockInfo> NewBlockInfo =
          Stream.ReadBlockInfoBlock(/*ReadBlockInfoNames=*/true);
      if (!NewBlockInfo)
        return ReportError("Malformed BlockInfoBlock");
      BlockInfo = std::move(*NewBlockInfo);
      Stream.JumpToBit(BlockBitStart);
      // It's not really interesting to dump the contents of the blockinfo block.
      DumpRecords = false;
    }
  
    unsigned NumWords = 0;
    if (Stream.EnterSubBlock(BlockID, &NumWords))
      return ReportError("Malformed block record");
  
    // Keep it for later, when we see a MODULE_HASH record
    uint64_t BlockEntryPos = Stream.getCurrentByteNo();
  
    const char *BlockName = nullptr;
    if (DumpRecords) {
      outs() << Indent << "<";
      if ((BlockName = GetBlockName(BlockID, BlockInfo, CurStreamType)))
        outs() << BlockName;
      else
        outs() << "UnknownBlock" << BlockID;
  
      if (NonSymbolic && BlockName)
        outs() << " BlockID=" << BlockID;
  
      outs() << " NumWords=" << NumWords
             << " BlockCodeSize=" << Stream.getAbbrevIDWidth() << ">\n";
    }
  
    SmallVector<uint64_t, 64> Record;
  
    // Keep the offset to the metadata index if seen.
    uint64_t MetadataIndexOffset = 0;
  
    // Read all the records for this block.
    while (1) {
      if (Stream.AtEndOfStream())
        return ReportError("Premature end of bitstream");
  
      uint64_t RecordStartBit = Stream.GetCurrentBitNo();
  
      BitstreamEntry Entry =
        Stream.advance(BitstreamCursor::AF_DontAutoprocessAbbrevs);
      
      switch (Entry.Kind) {
      case BitstreamEntry::Error:
        return ReportError("malformed bitcode file");
      case BitstreamEntry::EndBlock: {
        uint64_t BlockBitEnd = Stream.GetCurrentBitNo();
        BlockStats.NumBits += BlockBitEnd-BlockBitStart;
        if (DumpRecords) {
          outs() << Indent << "</";
          if (BlockName)
            outs() << BlockName << ">\n";
          else
            outs() << "UnknownBlock" << BlockID << ">\n";
        }
        return false;
      }
          
      case BitstreamEntry::SubBlock: {
        uint64_t SubBlockBitStart = Stream.GetCurrentBitNo();
        if (ParseBlock(Stream, BlockInfo, Entry.ID, IndentLevel + 1,
                       CurStreamType))
          return true;
        ++BlockStats.NumSubBlocks;
        uint64_t SubBlockBitEnd = Stream.GetCurrentBitNo();
        
        // Don't include subblock sizes in the size of this block.
        BlockBitStart += SubBlockBitEnd-SubBlockBitStart;
        continue;
      }
      case BitstreamEntry::Record:
        // The interesting case.
        break;
      }
  
      if (Entry.ID == bitc::DEFINE_ABBREV) {
        Stream.ReadAbbrevRecord();
        ++BlockStats.NumAbbrevs;
        continue;
      }
      
      Record.clear();
  
      ++BlockStats.NumRecords;
  
      StringRef Blob;
      uint64_t CurrentRecordPos = Stream.GetCurrentBitNo();
      unsigned Code = Stream.readRecord(Entry.ID, Record, &Blob);
  
      // Increment the # occurrences of this code.
      if (BlockStats.CodeFreq.size() <= Code)
        BlockStats.CodeFreq.resize(Code+1);
      BlockStats.CodeFreq[Code].NumInstances++;
      BlockStats.CodeFreq[Code].TotalBits +=
        Stream.GetCurrentBitNo()-RecordStartBit;
      if (Entry.ID != bitc::UNABBREV_RECORD) {
        BlockStats.CodeFreq[Code].NumAbbrev++;
        ++BlockStats.NumAbbreviatedRecords;
      }
  
      if (DumpRecords) {
        outs() << Indent << "  <";
        if (const char *CodeName =
                GetCodeName(Code, BlockID, BlockInfo, CurStreamType))
          outs() << CodeName;
        else
          outs() << "UnknownCode" << Code;
        if (NonSymbolic && GetCodeName(Code, BlockID, BlockInfo, CurStreamType))
          outs() << " codeid=" << Code;
        const BitCodeAbbrev *Abbv = nullptr;
        if (Entry.ID != bitc::UNABBREV_RECORD) {
          Abbv = Stream.getAbbrev(Entry.ID);
          outs() << " abbrevid=" << Entry.ID;
        }
  
        for (unsigned i = 0, e = Record.size(); i != e; ++i)
          outs() << " op" << i << "=" << (int64_t)Record[i];
  
        // If we found a metadata index, let's verify that we had an offset before
        // and validate its forward reference offset was correct!
        if (BlockID == bitc::METADATA_BLOCK_ID) {
          if (Code == bitc::METADATA_INDEX_OFFSET) {
            if (Record.size() != 2)
              outs() << "(Invalid record)";
            else {
              auto Offset = Record[0] + (Record[1] << 32);
              MetadataIndexOffset = Stream.GetCurrentBitNo() + Offset;
            }
          }
          if (Code == bitc::METADATA_INDEX) {
            outs() << " (offset ";
            if (MetadataIndexOffset == RecordStartBit)
              outs() << "match)";
            else
              outs() << "mismatch: " << MetadataIndexOffset << " vs "
                     << RecordStartBit << ")";
          }
        }
  
        // If we found a module hash, let's verify that it matches!
        if (BlockID == bitc::MODULE_BLOCK_ID && Code == bitc::MODULE_CODE_HASH &&
            !CheckHash.empty()) {
          if (Record.size() != 5)
            outs() << " (invalid)";
          else {
            // Recompute the hash and compare it to the one in the bitcode
            SHA1 Hasher;
            StringRef Hash;
            Hasher.update(CheckHash);
            {
              int BlockSize = (CurrentRecordPos / 8) - BlockEntryPos;
              auto Ptr = Stream.getPointerToByte(BlockEntryPos, BlockSize);
              Hasher.update(ArrayRef<uint8_t>(Ptr, BlockSize));
              Hash = Hasher.result();
            }
            SmallString<20> RecordedHash;
            RecordedHash.resize(20);
            int Pos = 0;
            for (auto &Val : Record) {
              assert(!(Val >> 32) && "Unexpected high bits set");
              RecordedHash[Pos++] = (Val >> 24) & 0xFF;
              RecordedHash[Pos++] = (Val >> 16) & 0xFF;
              RecordedHash[Pos++] = (Val >> 8) & 0xFF;
              RecordedHash[Pos++] = (Val >> 0) & 0xFF;
            }
            if (Hash == RecordedHash)
              outs() << " (match)";
            else
              outs() << " (!mismatch!)";
          }
        }
  
        outs() << "/>";
  
        if (Abbv) {
          for (unsigned i = 1, e = Abbv->getNumOperandInfos(); i != e; ++i) {
            const BitCodeAbbrevOp &Op = Abbv->getOperandInfo(i);
            if (!Op.isEncoding() || Op.getEncoding() != BitCodeAbbrevOp::Array)
              continue;
            assert(i + 2 == e && "Array op not second to last");
            std::string Str;
            bool ArrayIsPrintable = true;
            for (unsigned j = i - 1, je = Record.size(); j != je; ++j) {
              if (!isPrint(static_cast<unsigned char>(Record[j]))) {
                ArrayIsPrintable = false;
                break;
              }
              Str += (char)Record[j];
            }
            if (ArrayIsPrintable)
              outs() << " record string = '" << Str << "'";
            break;
          }
        }
  
        if (Blob.data() && decodeBlob(Code, BlockID, Indent, Record, Blob)) {
          outs() << " blob data = ";
          if (ShowBinaryBlobs) {
            outs() << "'";
            outs().write_escaped(Blob, /*hex=*/true) << "'";
          } else {
            bool BlobIsPrintable = true;
            for (unsigned i = 0, e = Blob.size(); i != e; ++i)
              if (!isPrint(static_cast<unsigned char>(Blob[i]))) {
                BlobIsPrintable = false;
                break;
              }
  
            if (BlobIsPrintable)
              outs() << "'" << Blob << "'";
            else
              outs() << "unprintable, " << Blob.size() << " bytes.";          
          }
        }
  
        outs() << "\n";
      }
  
      // Make sure that we can skip the current record.
      Stream.JumpToBit(CurrentRecordPos);
      Stream.skipRecord(Entry.ID);
    }
  }
  
  static void PrintSize(double Bits) {
    outs() << format("%.2f/%.2fB/%luW", Bits, Bits/8,(unsigned long)(Bits/32));
  }
  static void PrintSize(uint64_t Bits) {
    outs() << format("%lub/%.2fB/%luW", (unsigned long)Bits,
                     (double)Bits/8, (unsigned long)(Bits/32));
  }
  
  static CurStreamTypeType ReadSignature(BitstreamCursor &Stream) {
    char Signature[6];
    Signature[0] = Stream.Read(8);
    Signature[1] = Stream.Read(8);
  
    // Autodetect the file contents, if it is one we know.
    if (Signature[0] == 'C' && Signature[1] == 'P') {
      Signature[2] = Stream.Read(8);
      Signature[3] = Stream.Read(8);
      if (Signature[2] == 'C' && Signature[3] == 'H')
        return ClangSerializedASTBitstream;
    } else if (Signature[0] == 'D' && Signature[1] == 'I') {
      Signature[2] = Stream.Read(8);
      Signature[3] = Stream.Read(8);
      if (Signature[2] == 'A' && Signature[3] == 'G')
        return ClangSerializedDiagnosticsBitstream;
    } else {
      Signature[2] = Stream.Read(4);
      Signature[3] = Stream.Read(4);
      Signature[4] = Stream.Read(4);
      Signature[5] = Stream.Read(4);
      if (Signature[0] == 'B' && Signature[1] == 'C' &&
          Signature[2] == 0x0 && Signature[3] == 0xC &&
          Signature[4] == 0xE && Signature[5] == 0xD)
        return LLVMIRBitstream;
    }
    return UnknownBitstream;
  }
  
  static bool openBitcodeFile(StringRef Path,
                              std::unique_ptr<MemoryBuffer> &MemBuf,
                              BitstreamCursor &Stream,
                              CurStreamTypeType &CurStreamType) {
    // Read the input file.
    ErrorOr<std::unique_ptr<MemoryBuffer>> MemBufOrErr =
        MemoryBuffer::getFileOrSTDIN(Path);
    if (std::error_code EC = MemBufOrErr.getError())
      return ReportError(Twine("ReportError reading '") + Path + "': " + EC.message());
    MemBuf = std::move(MemBufOrErr.get());
  
    if (MemBuf->getBufferSize() & 3)
      return ReportError("Bitcode stream should be a multiple of 4 bytes in length");
  
    const unsigned char *BufPtr = (const unsigned char *)MemBuf->getBufferStart();
    const unsigned char *EndBufPtr = BufPtr + MemBuf->getBufferSize();
  
    // If we have a wrapper header, parse it and ignore the non-bc file contents.
    // The magic number is 0x0B17C0DE stored in little endian.
    if (isBitcodeWrapper(BufPtr, EndBufPtr)) {
      if (MemBuf->getBufferSize() < BWH_HeaderSize)
        return ReportError("Invalid bitcode wrapper header");
  
      if (Dump) {
        unsigned Magic = support::endian::read32le(&BufPtr[BWH_MagicField]);
        unsigned Version = support::endian::read32le(&BufPtr[BWH_VersionField]);
        unsigned Offset = support::endian::read32le(&BufPtr[BWH_OffsetField]);
        unsigned Size = support::endian::read32le(&BufPtr[BWH_SizeField]);
        unsigned CPUType = support::endian::read32le(&BufPtr[BWH_CPUTypeField]);
  
        outs() << "<BITCODE_WRAPPER_HEADER"
               << " Magic=" << format_hex(Magic, 10)
               << " Version=" << format_hex(Version, 10)
               << " Offset=" << format_hex(Offset, 10)
               << " Size=" << format_hex(Size, 10)
               << " CPUType=" << format_hex(CPUType, 10) << "/>\n";
      }
  
      if (SkipBitcodeWrapperHeader(BufPtr, EndBufPtr, true))
        return ReportError("Invalid bitcode wrapper header");
    }
  
    Stream = BitstreamCursor(ArrayRef<uint8_t>(BufPtr, EndBufPtr));
    CurStreamType = ReadSignature(Stream);
  
    return false;
  }
  
  /// AnalyzeBitcode - Analyze the bitcode file specified by InputFilename.
  static int AnalyzeBitcode() {
    std::unique_ptr<MemoryBuffer> StreamBuffer;
    BitstreamCursor Stream;
    BitstreamBlockInfo BlockInfo;
    CurStreamTypeType CurStreamType;
    if (openBitcodeFile(InputFilename, StreamBuffer, Stream, CurStreamType))
      return true;
    Stream.setBlockInfo(&BlockInfo);
  
    // Read block info from BlockInfoFilename, if specified.
    // The block info must be a top-level block.
    if (!BlockInfoFilename.empty()) {
      std::unique_ptr<MemoryBuffer> BlockInfoBuffer;
      BitstreamCursor BlockInfoCursor;
      CurStreamTypeType BlockInfoStreamType;
      if (openBitcodeFile(BlockInfoFilename, BlockInfoBuffer, BlockInfoCursor,
                          BlockInfoStreamType))
        return true;
  
      while (!BlockInfoCursor.AtEndOfStream()) {
        unsigned Code = BlockInfoCursor.ReadCode();
        if (Code != bitc::ENTER_SUBBLOCK)
          return ReportError("Invalid record at top-level in block info file");
  
        unsigned BlockID = BlockInfoCursor.ReadSubBlockID();
        if (BlockID == bitc::BLOCKINFO_BLOCK_ID) {
          Optional<BitstreamBlockInfo> NewBlockInfo =
              BlockInfoCursor.ReadBlockInfoBlock(/*ReadBlockInfoNames=*/true);
          if (!NewBlockInfo)
            return ReportError("Malformed BlockInfoBlock in block info file");
          BlockInfo = std::move(*NewBlockInfo);
          break;
        }
  
        BlockInfoCursor.SkipBlock();
      }
    }
  
    unsigned NumTopBlocks = 0;
  
    // Parse the top-level structure.  We only allow blocks at the top-level.
    while (!Stream.AtEndOfStream()) {
      unsigned Code = Stream.ReadCode();
      if (Code != bitc::ENTER_SUBBLOCK)
        return ReportError("Invalid record at top-level");
  
      unsigned BlockID = Stream.ReadSubBlockID();
  
      if (ParseBlock(Stream, BlockInfo, BlockID, 0, CurStreamType))
        return true;
      ++NumTopBlocks;
    }
  
    if (Dump) outs() << "\n\n";
  
    uint64_t BufferSizeBits = Stream.getBitcodeBytes().size() * CHAR_BIT;
    // Print a summary of the read file.
    outs() << "Summary of " << InputFilename << ":\n";
    outs() << "         Total size: ";
    PrintSize(BufferSizeBits);
    outs() << "\n";
    outs() << "        Stream type: ";
    switch (CurStreamType) {
    case UnknownBitstream:
      outs() << "unknown\n";
      break;
    case LLVMIRBitstream:
      outs() << "LLVM IR\n";
      break;
    case ClangSerializedASTBitstream:
      outs() << "Clang Serialized AST\n";
      break;
    case ClangSerializedDiagnosticsBitstream:
      outs() << "Clang Serialized Diagnostics\n";
      break;
    }
    outs() << "  # Toplevel Blocks: " << NumTopBlocks << "\n";
    outs() << "\n";
  
    // Emit per-block stats.
    outs() << "Per-block Summary:\n";
    for (std::map<unsigned, PerBlockIDStats>::iterator I = BlockIDStats.begin(),
         E = BlockIDStats.end(); I != E; ++I) {
      outs() << "  Block ID #" << I->first;
      if (const char *BlockName =
              GetBlockName(I->first, BlockInfo, CurStreamType))
        outs() << " (" << BlockName << ")";
      outs() << ":\n";
  
      const PerBlockIDStats &Stats = I->second;
      outs() << "      Num Instances: " << Stats.NumInstances << "\n";
      outs() << "         Total Size: ";
      PrintSize(Stats.NumBits);
      outs() << "\n";
      double pct = (Stats.NumBits * 100.0) / BufferSizeBits;
      outs() << "    Percent of file: " << format("%2.4f%%", pct) << "\n";
      if (Stats.NumInstances > 1) {
        outs() << "       Average Size: ";
        PrintSize(Stats.NumBits/(double)Stats.NumInstances);
        outs() << "\n";
        outs() << "  Tot/Avg SubBlocks: " << Stats.NumSubBlocks << "/"
               << Stats.NumSubBlocks/(double)Stats.NumInstances << "\n";
        outs() << "    Tot/Avg Abbrevs: " << Stats.NumAbbrevs << "/"
               << Stats.NumAbbrevs/(double)Stats.NumInstances << "\n";
        outs() << "    Tot/Avg Records: " << Stats.NumRecords << "/"
               << Stats.NumRecords/(double)Stats.NumInstances << "\n";
      } else {
        outs() << "      Num SubBlocks: " << Stats.NumSubBlocks << "\n";
        outs() << "        Num Abbrevs: " << Stats.NumAbbrevs << "\n";
        outs() << "        Num Records: " << Stats.NumRecords << "\n";
      }
      if (Stats.NumRecords) {
        double pct = (Stats.NumAbbreviatedRecords * 100.0) / Stats.NumRecords;
        outs() << "    Percent Abbrevs: " << format("%2.4f%%", pct) << "\n";
      }
      outs() << "\n";
  
      // Print a histogram of the codes we see.
      if (!NoHistogram && !Stats.CodeFreq.empty()) {
        std::vector<std::pair<unsigned, unsigned> > FreqPairs;  // <freq,code>
        for (unsigned i = 0, e = Stats.CodeFreq.size(); i != e; ++i)
          if (unsigned Freq = Stats.CodeFreq[i].NumInstances)
            FreqPairs.push_back(std::make_pair(Freq, i));
        std::stable_sort(FreqPairs.begin(), FreqPairs.end());
        std::reverse(FreqPairs.begin(), FreqPairs.end());
  
        outs() << "\tRecord Histogram:\n";
        outs() << "\t\t  Count    # Bits     b/Rec   % Abv  Record Kind\n";
        for (unsigned i = 0, e = FreqPairs.size(); i != e; ++i) {
          const PerRecordStats &RecStats = Stats.CodeFreq[FreqPairs[i].second];
  
          outs() << format("\t\t%7d %9lu",
                           RecStats.NumInstances,
                           (unsigned long)RecStats.TotalBits);
  
          if (RecStats.NumInstances > 1)
            outs() << format(" %9.1f",
                             (double)RecStats.TotalBits/RecStats.NumInstances);
          else
            outs() << "          ";
  
          if (RecStats.NumAbbrev)
            outs() <<
                format(" %7.2f",
                       (double)RecStats.NumAbbrev/RecStats.NumInstances*100);
          else
            outs() << "        ";
  
          outs() << "  ";
          if (const char *CodeName = GetCodeName(FreqPairs[i].second, I->first,
                                                 BlockInfo, CurStreamType))
            outs() << CodeName << "\n";
          else
            outs() << "UnknownCode" << FreqPairs[i].second << "\n";
        }
        outs() << "\n";
  
      }
    }
    return 0;
  }
  
  
  int main(int argc, char **argv) {
    InitLLVM X(argc, argv);
    cl::ParseCommandLineOptions(argc, argv, "llvm-bcanalyzer file analyzer\n");
    return AnalyzeBitcode();
  }
  