llvm/lib/Object/ObjectFile.cpp

   1 //===- ObjectFile.cpp - File format independent object file ---------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // This file defines a file format independent ObjectFile class.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/Object/ObjectFile.h"
  14 #include "llvm/ADT/StringRef.h"
  15 #include "llvm/BinaryFormat/Magic.h"
  16 #include "llvm/Object/Binary.h"
  17 #include "llvm/Object/COFF.h"
  18 #include "llvm/Object/Error.h"
  19 #include "llvm/Object/MachO.h"
  20 #include "llvm/Object/Wasm.h"
  21 #include "llvm/Support/Error.h"
  22 #include "llvm/Support/ErrorHandling.h"
  23 #include "llvm/Support/ErrorOr.h"
  24 #include "llvm/Support/FileSystem.h"
  25 #include "llvm/Support/MemoryBuffer.h"
  26 #include "llvm/Support/raw_ostream.h"
  27 #include <algorithm>
  28 #include <cstdint>
  29 #include <memory>
  30 #include <system_error>
  31
  32 using namespace llvm;
  33 using namespace object;
  34
  35 raw_ostream &object::operator<<(raw_ostream &OS, const SectionedAddress &Addr) {
  36   OS << "SectionedAddress{" << format_hex(Addr.Address, 10);
  37   if (Addr.SectionIndex != SectionedAddress::UndefSection)
  38     OS << ", " << Addr.SectionIndex;
  39   return OS << "}";
  40 }
  41
  42 void ObjectFile::anchor() {}
  43
  44 ObjectFile::ObjectFile(unsigned int Type, MemoryBufferRef Source)
  45     : SymbolicFile(Type, Source) {}
  46
  47 bool SectionRef::containsSymbol(SymbolRef S) const {
  48   Expected<section_iterator> SymSec = S.getSection();
  49   if (!SymSec) {
  50     // TODO: Actually report errors helpfully.
  51     consumeError(SymSec.takeError());
  52     return false;
  53   }
  54   return *this == **SymSec;
  55 }
  56
  57 Expected<uint64_t> ObjectFile::getSymbolValue(DataRefImpl Ref) const {
  58   if (Expected<uint32_t> FlagsOrErr = getSymbolFlags(Ref)) {
  59     if (*FlagsOrErr & SymbolRef::SF_Undefined)
  60       return 0;
  61     if (*FlagsOrErr & SymbolRef::SF_Common)
  62       return getCommonSymbolSize(Ref);
  63   } else
  64     // TODO: Test this error.
  65     return FlagsOrErr.takeError();
  66   return getSymbolValueImpl(Ref);
  67 }
  68
  69 Error ObjectFile::printSymbolName(raw_ostream &OS, DataRefImpl Symb) const {
  70   Expected<StringRef> Name = getSymbolName(Symb);
  71   if (!Name)
  72     return Name.takeError();
  73   OS << *Name;
  74   return Error::success();
  75 }
  76
  77 uint32_t ObjectFile::getSymbolAlignment(DataRefImpl DRI) const { return 0; }
  78
  79 bool ObjectFile::isSectionBitcode(DataRefImpl Sec) const {
  80   Expected<StringRef> NameOrErr = getSectionName(Sec);
  81   if (NameOrErr)
  82     return *NameOrErr == ".llvmbc";
  83   consumeError(NameOrErr.takeError());
  84   return false;
  85 }
  86
  87 bool ObjectFile::isSectionStripped(DataRefImpl Sec) const { return false; }
  88
  89 bool ObjectFile::isBerkeleyText(DataRefImpl Sec) const {
  90   return isSectionText(Sec);
  91 }
  92
  93 bool ObjectFile::isBerkeleyData(DataRefImpl Sec) const {
  94   return isSectionData(Sec);
  95 }
  96
  97 bool ObjectFile::isDebugSection(DataRefImpl Sec) const { return false; }
  98
  99 Expected<section_iterator>
 100 ObjectFile::getRelocatedSection(DataRefImpl Sec) const {
 101   return section_iterator(SectionRef(Sec, this));
 102 }
 103
 104 Triple ObjectFile::makeTriple() const {
 105   Triple TheTriple;
 106   auto Arch = getArch();
 107   TheTriple.setArch(Triple::ArchType(Arch));
 108
 109   // For ARM targets, try to use the build attributes to build determine
 110   // the build target. Target features are also added, but later during
 111   // disassembly.
 112   if (Arch == Triple::arm || Arch == Triple::armeb)
 113     setARMSubArch(TheTriple);
 114
 115   // TheTriple defaults to ELF, and COFF doesn't have an environment:
 116   // something we can do here is indicate that it is mach-o.
 117   if (isMachO()) {
 118     TheTriple.setObjectFormat(Triple::MachO);
 119   } else if (isCOFF()) {
 120     const auto COFFObj = cast<COFFObjectFile>(this);
 121     if (COFFObj->getArch() == Triple::thumb)
 122       TheTriple.setTriple("thumbv7-windows");
 123   } else if (isXCOFF()) {
 124     // XCOFF implies AIX.
 125     TheTriple.setOS(Triple::AIX);
 126     TheTriple.setObjectFormat(Triple::XCOFF);
 127   }
 128
 129   return TheTriple;
 130 }
 131
 132 Expected<std::unique_ptr<ObjectFile>>
 133 ObjectFile::createObjectFile(MemoryBufferRef Object, file_magic Type,
 134                              bool InitContent) {
 135   StringRef Data = Object.getBuffer();
 136   if (Type == file_magic::unknown)
 137     Type = identify_magic(Data);
 138
 139   switch (Type) {
 140   case file_magic::unknown:
 141   case file_magic::bitcode:
 142   case file_magic::coff_cl_gl_object:
 143   case file_magic::archive:
 144   case file_magic::macho_universal_binary:
 145   case file_magic::windows_resource:
 146   case file_magic::pdb:
 147   case file_magic::minidump:
 148   case file_magic::goff_object:
 149     return errorCodeToError(object_error::invalid_file_type);
 150   case file_magic::tapi_file:
 151     return errorCodeToError(object_error::invalid_file_type);
 152   case file_magic::elf:
 153   case file_magic::elf_relocatable:
 154   case file_magic::elf_executable:
 155   case file_magic::elf_shared_object:
 156   case file_magic::elf_core:
 157     return createELFObjectFile(Object, InitContent);
 158   case file_magic::macho_object:
 159   case file_magic::macho_executable:
 160   case file_magic::macho_fixed_virtual_memory_shared_lib:
 161   case file_magic::macho_core:
 162   case file_magic::macho_preload_executable:
 163   case file_magic::macho_dynamically_linked_shared_lib:
 164   case file_magic::macho_dynamic_linker:
 165   case file_magic::macho_bundle:
 166   case file_magic::macho_dynamically_linked_shared_lib_stub:
 167   case file_magic::macho_dsym_companion:
 168   case file_magic::macho_kext_bundle:
 169     return createMachOObjectFile(Object);
 170   case file_magic::coff_object:
 171   case file_magic::coff_import_library:
 172   case file_magic::pecoff_executable:
 173     return createCOFFObjectFile(Object);
 174   case file_magic::xcoff_object_32:
 175     return createXCOFFObjectFile(Object, Binary::ID_XCOFF32);
 176   case file_magic::xcoff_object_64:
 177     return createXCOFFObjectFile(Object, Binary::ID_XCOFF64);
 178   case file_magic::wasm_object:
 179     return createWasmObjectFile(Object);
 180   }
 181   llvm_unreachable("Unexpected Object File Type");
 182 }
 183
 184 Expected<OwningBinary<ObjectFile>>
 185 ObjectFile::createObjectFile(StringRef ObjectPath) {
 186   ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
 187       MemoryBuffer::getFile(ObjectPath);
 188   if (std::error_code EC = FileOrErr.getError())
 189     return errorCodeToError(EC);
 190   std::unique_ptr<MemoryBuffer> Buffer = std::move(FileOrErr.get());
 191
 192   Expected<std::unique_ptr<ObjectFile>> ObjOrErr =
 193       createObjectFile(Buffer->getMemBufferRef());
 194   if (Error Err = ObjOrErr.takeError())
 195     return std::move(Err);
 196   std::unique_ptr<ObjectFile> Obj = std::move(ObjOrErr.get());
 197
 198   return OwningBinary<ObjectFile>(std::move(Obj), std::move(Buffer));
 199 }