Coverage Report

Created: 2018-07-18 22:01

/Users/buildslave/jenkins/workspace/clang-stage2-coverage-R/llvm/include/llvm/Bitcode/BitcodeReader.h
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//===- llvm/Bitcode/BitcodeReader.h - Bitcode reader ------------*- C++ -*-===//
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//
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//                     The LLVM Compiler Infrastructure
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//
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// This file is distributed under the University of Illinois Open Source
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// License. See LICENSE.TXT for details.
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//
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//===----------------------------------------------------------------------===//
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//
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// This header defines interfaces to read LLVM bitcode files/streams.
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//
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//===----------------------------------------------------------------------===//
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#ifndef LLVM_BITCODE_BITCODEREADER_H
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#define LLVM_BITCODE_BITCODEREADER_H
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#include "llvm/ADT/ArrayRef.h"
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#include "llvm/ADT/StringRef.h"
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#include "llvm/Bitcode/BitCodes.h"
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#include "llvm/IR/ModuleSummaryIndex.h"
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#include "llvm/Support/Endian.h"
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#include "llvm/Support/Error.h"
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#include "llvm/Support/ErrorOr.h"
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#include "llvm/Support/MemoryBuffer.h"
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#include <cstdint>
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#include <memory>
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#include <string>
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#include <system_error>
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#include <vector>
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namespace llvm {
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class LLVMContext;
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class Module;
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  // These functions are for converting Expected/Error values to
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  // ErrorOr/std::error_code for compatibility with legacy clients. FIXME:
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  // Remove these functions once no longer needed by the C and libLTO APIs.
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  std::error_code errorToErrorCodeAndEmitErrors(LLVMContext &Ctx, Error Err);
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  template <typename T>
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  ErrorOr<T> expectedToErrorOrAndEmitErrors(LLVMContext &Ctx, Expected<T> Val) {
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    if (!Val)
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      return errorToErrorCodeAndEmitErrors(Ctx, Val.takeError());
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    return std::move(*Val);
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  }
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  struct BitcodeFileContents;
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  /// Basic information extracted from a bitcode module to be used for LTO.
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  struct BitcodeLTOInfo {
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    bool IsThinLTO;
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    bool HasSummary;
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  };
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  /// Represents a module in a bitcode file.
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  class BitcodeModule {
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    // This covers the identification (if present) and module blocks.
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    ArrayRef<uint8_t> Buffer;
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    StringRef ModuleIdentifier;
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    // The string table used to interpret this module.
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    StringRef Strtab;
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    // The bitstream location of the IDENTIFICATION_BLOCK.
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    uint64_t IdentificationBit;
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    // The bitstream location of this module's MODULE_BLOCK.
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    uint64_t ModuleBit;
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    BitcodeModule(ArrayRef<uint8_t> Buffer, StringRef ModuleIdentifier,
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                  uint64_t IdentificationBit, uint64_t ModuleBit)
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        : Buffer(Buffer), ModuleIdentifier(ModuleIdentifier),
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          IdentificationBit(IdentificationBit), ModuleBit(ModuleBit) {}
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    // Calls the ctor.
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    friend Expected<BitcodeFileContents>
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    getBitcodeFileContents(MemoryBufferRef Buffer);
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    Expected<std::unique_ptr<Module>> getModuleImpl(LLVMContext &Context,
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                                                    bool MaterializeAll,
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                                                    bool ShouldLazyLoadMetadata,
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                                                    bool IsImporting);
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  public:
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    StringRef getBuffer() const {
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      return StringRef((const char *)Buffer.begin(), Buffer.size());
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    }
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    StringRef getStrtab() const { return Strtab; }
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    StringRef getModuleIdentifier() const { return ModuleIdentifier; }
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    /// Read the bitcode module and prepare for lazy deserialization of function
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    /// bodies. If ShouldLazyLoadMetadata is true, lazily load metadata as well.
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    /// If IsImporting is true, this module is being parsed for ThinLTO
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    /// importing into another module.
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    Expected<std::unique_ptr<Module>> getLazyModule(LLVMContext &Context,
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                                                    bool ShouldLazyLoadMetadata,
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                                                    bool IsImporting);
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    /// Read the entire bitcode module and return it.
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    Expected<std::unique_ptr<Module>> parseModule(LLVMContext &Context);
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    /// Returns information about the module to be used for LTO: whether to
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    /// compile with ThinLTO, and whether it has a summary.
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    Expected<BitcodeLTOInfo> getLTOInfo();
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    /// Parse the specified bitcode buffer, returning the module summary index.
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    Expected<std::unique_ptr<ModuleSummaryIndex>> getSummary();
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    /// Parse the specified bitcode buffer and merge its module summary index
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    /// into CombinedIndex.
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    Error readSummary(ModuleSummaryIndex &CombinedIndex, StringRef ModulePath,
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                      uint64_t ModuleId);
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  };
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  struct BitcodeFileContents {
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    std::vector<BitcodeModule> Mods;
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    StringRef Symtab, StrtabForSymtab;
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  };
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  /// Returns the contents of a bitcode file. This includes the raw contents of
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  /// the symbol table embedded in the bitcode file. Clients which require a
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  /// symbol table should prefer to use irsymtab::read instead of this function
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  /// because it creates a reader for the irsymtab and handles upgrading bitcode
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  /// files without a symbol table or with an old symbol table.
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  Expected<BitcodeFileContents> getBitcodeFileContents(MemoryBufferRef Buffer);
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  /// Returns a list of modules in the specified bitcode buffer.
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  Expected<std::vector<BitcodeModule>>
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  getBitcodeModuleList(MemoryBufferRef Buffer);
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  /// Read the header of the specified bitcode buffer and prepare for lazy
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  /// deserialization of function bodies. If ShouldLazyLoadMetadata is true,
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  /// lazily load metadata as well. If IsImporting is true, this module is
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  /// being parsed for ThinLTO importing into another module.
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  Expected<std::unique_ptr<Module>>
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  getLazyBitcodeModule(MemoryBufferRef Buffer, LLVMContext &Context,
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                       bool ShouldLazyLoadMetadata = false,
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                       bool IsImporting = false);
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  /// Like getLazyBitcodeModule, except that the module takes ownership of
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  /// the memory buffer if successful. If successful, this moves Buffer. On
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  /// error, this *does not* move Buffer. If IsImporting is true, this module is
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  /// being parsed for ThinLTO importing into another module.
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  Expected<std::unique_ptr<Module>> getOwningLazyBitcodeModule(
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      std::unique_ptr<MemoryBuffer> &&Buffer, LLVMContext &Context,
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      bool ShouldLazyLoadMetadata = false, bool IsImporting = false);
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  /// Read the header of the specified bitcode buffer and extract just the
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  /// triple information. If successful, this returns a string. On error, this
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  /// returns "".
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  Expected<std::string> getBitcodeTargetTriple(MemoryBufferRef Buffer);
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  /// Return true if \p Buffer contains a bitcode file with ObjC code (category
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  /// or class) in it.
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  Expected<bool> isBitcodeContainingObjCCategory(MemoryBufferRef Buffer);
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  /// Read the header of the specified bitcode buffer and extract just the
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  /// producer string information. If successful, this returns a string. On
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  /// error, this returns "".
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  Expected<std::string> getBitcodeProducerString(MemoryBufferRef Buffer);
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  /// Read the specified bitcode file, returning the module.
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  Expected<std::unique_ptr<Module>> parseBitcodeFile(MemoryBufferRef Buffer,
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                                                     LLVMContext &Context);
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  /// Returns LTO information for the specified bitcode file.
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  Expected<BitcodeLTOInfo> getBitcodeLTOInfo(MemoryBufferRef Buffer);
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  /// Parse the specified bitcode buffer, returning the module summary index.
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  Expected<std::unique_ptr<ModuleSummaryIndex>>
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  getModuleSummaryIndex(MemoryBufferRef Buffer);
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  /// Parse the specified bitcode buffer and merge the index into CombinedIndex.
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  Error readModuleSummaryIndex(MemoryBufferRef Buffer,
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                               ModuleSummaryIndex &CombinedIndex,
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                               uint64_t ModuleId);
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  /// Parse the module summary index out of an IR file and return the module
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  /// summary index object if found, or an empty summary if not. If Path refers
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  /// to an empty file and IgnoreEmptyThinLTOIndexFile is true, then
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  /// this function will return nullptr.
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  Expected<std::unique_ptr<ModuleSummaryIndex>>
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  getModuleSummaryIndexForFile(StringRef Path,
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                               bool IgnoreEmptyThinLTOIndexFile = false);
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  /// isBitcodeWrapper - Return true if the given bytes are the magic bytes
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  /// for an LLVM IR bitcode wrapper.
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  inline bool isBitcodeWrapper(const unsigned char *BufPtr,
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                               const unsigned char *BufEnd) {
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    // See if you can find the hidden message in the magic bytes :-).
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    // (Hint: it's a little-endian encoding.)
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    return BufPtr != BufEnd &&
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BufPtr[0] == 0xDE42.1k
&&
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BufPtr[1] == 0xC0773
&&
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BufPtr[2] == 0x17774
&&
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BufPtr[3] == 0x0B774
;
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  }
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  /// isRawBitcode - Return true if the given bytes are the magic bytes for
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  /// raw LLVM IR bitcode (without a wrapper).
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  inline bool isRawBitcode(const unsigned char *BufPtr,
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                           const unsigned char *BufEnd) {
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    // These bytes sort of have a hidden message, but it's not in
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    // little-endian this time, and it's a little redundant.
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    return BufPtr != BufEnd &&
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BufPtr[0] == 'B'33.1k
&&
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BufPtr[1] == 'C'4.47k
&&
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BufPtr[2] == 0xc04.47k
&&
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BufPtr[3] == 0xde4.47k
;
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  }
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  /// isBitcode - Return true if the given bytes are the magic bytes for
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  /// LLVM IR bitcode, either with or without a wrapper.
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  inline bool isBitcode(const unsigned char *BufPtr,
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                        const unsigned char *BufEnd) {
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    return isBitcodeWrapper(BufPtr, BufEnd) ||
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isRawBitcode(BufPtr, BufEnd)33.1k
;
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  }
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  /// SkipBitcodeWrapperHeader - Some systems wrap bc files with a special
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  /// header for padding or other reasons.  The format of this header is:
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  ///
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  /// struct bc_header {
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  ///   uint32_t Magic;         // 0x0B17C0DE
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  ///   uint32_t Version;       // Version, currently always 0.
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  ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
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  ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
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  ///   ... potentially other gunk ...
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  /// };
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  ///
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  /// This function is called when we find a file with a matching magic number.
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  /// In this case, skip down to the subsection of the file that is actually a
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  /// BC file.
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  /// If 'VerifyBufferSize' is true, check that the buffer is large enough to
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  /// contain the whole bitcode file.
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  inline bool SkipBitcodeWrapperHeader(const unsigned char *&BufPtr,
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                                       const unsigned char *&BufEnd,
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                                       bool VerifyBufferSize) {
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    // Must contain the offset and size field!
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    if (unsigned(BufEnd - BufPtr) < BWH_SizeField + 4)
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      return true;
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    unsigned Offset = support::endian::read32le(&BufPtr[BWH_OffsetField]);
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    unsigned Size = support::endian::read32le(&BufPtr[BWH_SizeField]);
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    uint64_t BitcodeOffsetEnd = (uint64_t)Offset + (uint64_t)Size;
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    // Verify that Offset+Size fits in the file.
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    if (
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&& BitcodeOffsetEnd > uint64_t(BufEnd-BufPtr))
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      return true;
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    BufPtr += Offset;
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    BufEnd = BufPtr+Size;
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    return false;
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  }
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  const std::error_category &BitcodeErrorCategory();
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  enum class BitcodeError { CorruptedBitcode = 1 };
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  inline std::error_code make_error_code(BitcodeError E) {
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    return std::error_code(static_cast<int>(E), BitcodeErrorCategory());
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  }
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} // end namespace llvm
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namespace std {
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template <> struct is_error_code_enum<llvm::BitcodeError> : std::true_type {};
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} // end namespace std
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#endif // LLVM_BITCODE_BITCODEREADER_H