CopyConfig.h

//===- CopyConfig.h -------------------------------------------------------===//
//
// 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
//
//===----------------------------------------------------------------------===//

#ifndef LLVM_TOOLS_LLVM_OBJCOPY_COPY_CONFIG_H
#define LLVM_TOOLS_LLVM_OBJCOPY_COPY_CONFIG_H

#include "llvm/ADT/ArrayRef.h"
#include "llvm/ADT/BitmaskEnum.h"
#include "llvm/ADT/Optional.h"
#include "llvm/ADT/SmallVector.h"
#include "llvm/ADT/StringMap.h"
#include "llvm/ADT/StringRef.h"
#include "llvm/Object/ELFTypes.h"
#include "llvm/Support/Allocator.h"
#include "llvm/Support/Error.h"
#include "llvm/Support/Regex.h"
// Necessary for llvm::DebugCompressionType::None
#include "llvm/Target/TargetOptions.h"
#include <vector>

namespace llvm {
namespace objcopy {

enum class FileFormat {
  Unspecified,
  ELF,
  Binary,
  IHex,
};

// This type keeps track of the machine info for various architectures. This
// lets us map architecture names to ELF types and the e_machine value of the
// ELF file.
struct MachineInfo {
  MachineInfo(uint16_t EM, uint8_t ABI, bool Is64, bool IsLittle)
      : EMachine(EM), OSABI(ABI), Is64Bit(Is64), IsLittleEndian(IsLittle) {}
  // Alternative constructor that defaults to NONE for OSABI.
  MachineInfo(uint16_t EM, bool Is64, bool IsLittle)
      : MachineInfo(EM, ELF::ELFOSABI_NONE, Is64, IsLittle) {}
  // Default constructor for unset fields.
  MachineInfo() : MachineInfo(0, 0, false, false) {}
  uint16_t EMachine;
  uint8_t OSABI;
  bool Is64Bit;
  bool IsLittleEndian;
};

// Flags set by --set-section-flags or --rename-section. Interpretation of these
// is format-specific and not all flags are meaningful for all object file
// formats. This is a bitmask; many section flags may be set.
enum SectionFlag {
  SecNone = 0,
  SecAlloc = 1 << 0,
  SecLoad = 1 << 1,
  SecNoload = 1 << 2,
  SecReadonly = 1 << 3,
  SecDebug = 1 << 4,
  SecCode = 1 << 5,
  SecData = 1 << 6,
  SecRom = 1 << 7,
  SecMerge = 1 << 8,
  SecStrings = 1 << 9,
  SecContents = 1 << 10,
  SecShare = 1 << 11,
  LLVM_MARK_AS_BITMASK_ENUM(/* LargestValue = */ SecShare)
};

struct SectionRename {
  StringRef OriginalName;
  StringRef NewName;
  Optional<SectionFlag> NewFlags;
};

struct SectionFlagsUpdate {
  StringRef Name;
  SectionFlag NewFlags;
};

enum class DiscardType {
  None,   // Default
  All,    // --discard-all (-x)
  Locals, // --discard-locals (-X)
};

class NameOrRegex {
  StringRef Name;
  // Regex is shared between multiple CopyConfig instances.
  std::shared_ptr<Regex> R;

public:
  NameOrRegex(StringRef Pattern, bool IsRegex);
  bool operator==(StringRef S) const { return R ? R->match(S) : Name == S; }
  bool operator!=(StringRef S) const { return !operator==(S); }
};

// Matcher that checks symbol or section names against the command line flags
// provided for that option.
class NameMatcher {
  std::vector<NameOrRegex> Matchers;

public:
  void addMatcher(NameOrRegex Matcher) {
    Matchers.push_back(std::move(Matcher));
  }
  bool matches(StringRef S) const { return is_contained(Matchers, S); }
  bool empty() const { return Matchers.empty(); }
};

struct NewSymbolInfo {
  StringRef SymbolName;
  StringRef SectionName;
  uint64_t Value = 0;
  uint8_t Type = ELF::STT_NOTYPE;
  uint8_t Bind = ELF::STB_GLOBAL;
  uint8_t Visibility = ELF::STV_DEFAULT;
};

// Configuration for copying/stripping a single file.
struct CopyConfig {
  // Main input/output options
  StringRef InputFilename;
  FileFormat InputFormat;
  StringRef OutputFilename;
  FileFormat OutputFormat;

  // Only applicable for --input-format=binary
  MachineInfo BinaryArch;
  // Only applicable when --output-format!=binary (e.g. elf64-x86-64).
  Optional<MachineInfo> OutputArch;

  // Advanced options
  StringRef AddGnuDebugLink;
  // Cached gnu_debuglink's target CRC
  uint32_t GnuDebugLinkCRC32;
  StringRef BuildIdLinkDir;
  Optional<StringRef> BuildIdLinkInput;
  Optional<StringRef> BuildIdLinkOutput;
  Optional<StringRef> ExtractPartition;
  StringRef SplitDWO;
  StringRef SymbolsPrefix;
  StringRef AllocSectionsPrefix;
  DiscardType DiscardMode = DiscardType::None;
  Optional<uint8_t> NewSymbolVisibility;

  // Repeated options
  std::vector<StringRef> AddSection;
  std::vector<StringRef> DumpSection;
  std::vector<NewSymbolInfo> SymbolsToAdd;

  // Section matchers
  NameMatcher KeepSection;
  NameMatcher OnlySection;
  NameMatcher ToRemove;

  // Symbol matchers
  NameMatcher SymbolsToGlobalize;
  NameMatcher SymbolsToKeep;
  NameMatcher SymbolsToLocalize;
  NameMatcher SymbolsToRemove;
  NameMatcher UnneededSymbolsToRemove;
  NameMatcher SymbolsToWeaken;
  NameMatcher SymbolsToKeepGlobal;

  // Map options
  StringMap<SectionRename> SectionsToRename;
  StringMap<SectionFlagsUpdate> SetSectionFlags;
  StringMap<StringRef> SymbolsToRename;

  // ELF entry point address expression. The input parameter is an entry point
  // address in the input ELF file. The entry address in the output file is
  // calculated with EntryExpr(input_address), when either --set-start or
  // --change-start is used.
  std::function<uint64_t(uint64_t)> EntryExpr;

  // Boolean options
  bool AllowBrokenLinks = false;
  bool DeterministicArchives = true;
  bool ExtractDWO = false;
  bool ExtractMainPartition = false;
  bool KeepFileSymbols = false;
  bool LocalizeHidden = false;
  bool OnlyKeepDebug = false;
  bool PreserveDates = false;
  bool StripAll = false;
  bool StripAllGNU = false;
  bool StripDWO = false;
  bool StripDebug = false;
  bool StripNonAlloc = false;
  bool StripSections = false;
  bool StripUnneeded = false;
  bool Weaken = false;
  bool DecompressDebugSections = false;
  DebugCompressionType CompressionType = DebugCompressionType::None;
};

// Configuration for the overall invocation of this tool. When invoked as
// objcopy, will always contain exactly one CopyConfig. When invoked as strip,
// will contain one or more CopyConfigs.
struct DriverConfig {
  SmallVector<CopyConfig, 1> CopyConfigs;
  BumpPtrAllocator Alloc;
};

// ParseObjcopyOptions returns the config and sets the input arguments. If a
// help flag is set then ParseObjcopyOptions will print the help messege and
// exit.
Expected<DriverConfig> parseObjcopyOptions(ArrayRef<const char *> ArgsArr);

// ParseStripOptions returns the config and sets the input arguments. If a
// help flag is set then ParseStripOptions will print the help messege and
// exit. ErrorCallback is used to handle recoverable errors. An Error returned
// by the callback aborts the parsing and is then returned by this function.
Expected<DriverConfig>
parseStripOptions(ArrayRef<const char *> ArgsArr,
                  std::function<Error(Error)> ErrorCallback);

} // namespace objcopy
} // namespace llvm

#endif