BitcodeReader.h | Explore in Territory

//===- llvm/Bitcode/BitcodeReader.h - Bitcode reader ------------*- C++ -*-===//
//
// 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 header defines interfaces to read LLVM bitcode files/streams.
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_BITCODE_BITCODEREADER_H
#define LLVM_BITCODE_BITCODEREADER_H

#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Bitstream/BitCodeEnums.h"
#include "llvm/IR/GlobalValue.h"
#include "llvm/Support/Endian.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/ErrorOr.h"
#include "llvm/Support/MemoryBufferRef.h"
#include <cstdint>
#include <memory>
#include <optional>
#include <string>
#include <system_error>
#include <vector>
namespace llvm {

class LLVMContext;
class Module;
class MemoryBuffer;
class Metadata;
class ModuleSummaryIndex;
class Type;
class Value;

// Callback to override the data layout string of an imported bitcode module.
// The first argument is the target triple, the second argument the data layout
// string from the input, or a default string. It will be used if the callback
// returns std::nullopt.
DataLayoutCallbackFuncTy;

GetTypeByIDTy;

GetContainedTypeIDTy;

ValueTypeCallbackTy;

MDTypeCallbackTy;

// These functions are for converting Expected/Error values to
// ErrorOr/std::error_code for compatibility with legacy clients. FIXME:
// Remove these functions once no longer needed by the C and libLTO APIs.

std::error_code errorToErrorCodeAndEmitErrors(LLVMContext &Ctx, Error Err);

template <typename T>
ErrorOr<T> expectedToErrorOrAndEmitErrors(LLVMContext &Ctx, Expected<T> Val) { … }

struct ParserCallbacks { … };

  struct BitcodeFileContents;

  /// Basic information extracted from a bitcode module to be used for LTO.
  struct BitcodeLTOInfo { … };

  /// Represents a module in a bitcode file.
  class BitcodeModule { … };

  struct BitcodeFileContents { … };

  /// Returns the contents of a bitcode file. This includes the raw contents of
  /// the symbol table embedded in the bitcode file. Clients which require a
  /// symbol table should prefer to use irsymtab::read instead of this function
  /// because it creates a reader for the irsymtab and handles upgrading bitcode
  /// files without a symbol table or with an old symbol table.
  Expected<BitcodeFileContents> getBitcodeFileContents(MemoryBufferRef Buffer);

  /// Returns a list of modules in the specified bitcode buffer.
  Expected<std::vector<BitcodeModule>>
  getBitcodeModuleList(MemoryBufferRef Buffer);

  /// Read the header of the specified bitcode buffer and prepare for lazy
  /// deserialization of function bodies. If ShouldLazyLoadMetadata is true,
  /// lazily load metadata as well. If IsImporting is true, this module is
  /// being parsed for ThinLTO importing into another module.
  Expected<std::unique_ptr<Module>>
  getLazyBitcodeModule(MemoryBufferRef Buffer, LLVMContext &Context,
                       bool ShouldLazyLoadMetadata = false,
                       bool IsImporting = false,
                       ParserCallbacks Callbacks = { … };

  /// Like getLazyBitcodeModule, except that the module takes ownership of
  /// the memory buffer if successful. If successful, this moves Buffer. On
  /// error, this *does not* move Buffer. If IsImporting is true, this module is
  /// being parsed for ThinLTO importing into another module.
  Expected<std::unique_ptr<Module>> getOwningLazyBitcodeModule(
      std::unique_ptr<MemoryBuffer> &&Buffer, LLVMContext &Context,
      bool ShouldLazyLoadMetadata = false, bool IsImporting = false,
      ParserCallbacks Callbacks = { … };

  /// Read the header of the specified bitcode buffer and extract just the
  /// triple information. If successful, this returns a string. On error, this
  /// returns "".
  Expected<std::string> getBitcodeTargetTriple(MemoryBufferRef Buffer);

  /// Return true if \p Buffer contains a bitcode file with ObjC code (category
  /// or class) in it.
  Expected<bool> isBitcodeContainingObjCCategory(MemoryBufferRef Buffer);

  /// Read the header of the specified bitcode buffer and extract just the
  /// producer string information. If successful, this returns a string. On
  /// error, this returns "".
  Expected<std::string> getBitcodeProducerString(MemoryBufferRef Buffer);

  /// Read the specified bitcode file, returning the module.
  Expected<std::unique_ptr<Module>>
  parseBitcodeFile(MemoryBufferRef Buffer, LLVMContext &Context,
                   ParserCallbacks Callbacks = { … };

  /// Returns LTO information for the specified bitcode file.
  Expected<BitcodeLTOInfo> getBitcodeLTOInfo(MemoryBufferRef Buffer);

  /// Parse the specified bitcode buffer, returning the module summary index.
  Expected<std::unique_ptr<ModuleSummaryIndex>>
  getModuleSummaryIndex(MemoryBufferRef Buffer);

  /// Parse the specified bitcode buffer and merge the index into CombinedIndex.
  Error readModuleSummaryIndex(MemoryBufferRef Buffer,
                               ModuleSummaryIndex &CombinedIndex);

  /// Parse the module summary index out of an IR file and return the module
  /// summary index object if found, or an empty summary if not. If Path refers
  /// to an empty file and IgnoreEmptyThinLTOIndexFile is true, then
  /// this function will return nullptr.
  Expected<std::unique_ptr<ModuleSummaryIndex>>
  getModuleSummaryIndexForFile(StringRef Path,
                               bool IgnoreEmptyThinLTOIndexFile = false);

  /// isBitcodeWrapper - Return true if the given bytes are the magic bytes
  /// for an LLVM IR bitcode wrapper.
  inline bool isBitcodeWrapper(const unsigned char *BufPtr,
                               const unsigned char *BufEnd) { … }

  /// isRawBitcode - Return true if the given bytes are the magic bytes for
  /// raw LLVM IR bitcode (without a wrapper).
  inline bool isRawBitcode(const unsigned char *BufPtr,
                           const unsigned char *BufEnd) { … }

  /// isBitcode - Return true if the given bytes are the magic bytes for
  /// LLVM IR bitcode, either with or without a wrapper.
  inline bool isBitcode(const unsigned char *BufPtr,
                        const unsigned char *BufEnd) { … }

  /// SkipBitcodeWrapperHeader - Some systems wrap bc files with a special
  /// header for padding or other reasons.  The format of this header is:
  ///
  /// struct bc_header {
  ///   uint32_t Magic;         // 0x0B17C0DE
  ///   uint32_t Version;       // Version, currently always 0.
  ///   uint32_t BitcodeOffset; // Offset to traditional bitcode file.
  ///   uint32_t BitcodeSize;   // Size of traditional bitcode file.
  ///   ... potentially other gunk ...
  /// };
  ///
  /// This function is called when we find a file with a matching magic number.
  /// In this case, skip down to the subsection of the file that is actually a
  /// BC file.
  /// If 'VerifyBufferSize' is true, check that the buffer is large enough to
  /// contain the whole bitcode file.
  inline bool SkipBitcodeWrapperHeader(const unsigned char *&BufPtr,
                                       const unsigned char *&BufEnd,
                                       bool VerifyBufferSize) { … }

  APInt readWideAPInt(ArrayRef<uint64_t> Vals, unsigned TypeBits);

  const std::error_category &BitcodeErrorCategory();
  enum class BitcodeError { … };
  inline std::error_code make_error_code(BitcodeError E) { … }

} // end namespace llvm

namespace std {

template <> struct is_error_code_enum<llvm::BitcodeError> : std::true_type { … };

} // end namespace std

#endif // LLVM_BITCODE_BITCODEREADER_H
llvm/llvm/include/llvm/Bitcode/BitcodeReader.h
