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 void ObjectFile::anchor() {}
  36
  37 ObjectFile::ObjectFile(unsigned int Type, MemoryBufferRef Source)
  38     : SymbolicFile(Type, Source) {}
  39
  40 bool SectionRef::containsSymbol(SymbolRef S) const {
  41   Expected<section_iterator> SymSec = S.getSection();
  42   if (!SymSec) {
  43     // TODO: Actually report errors helpfully.
  44     consumeError(SymSec.takeError());
  45     return false;
  46   }
  47   return *this == **SymSec;
  48 }
  49
  50 uint64_t ObjectFile::getSymbolValue(DataRefImpl Ref) const {
  51   uint32_t Flags = getSymbolFlags(Ref);
  52   if (Flags & SymbolRef::SF_Undefined)
  53     return 0;
  54   if (Flags & SymbolRef::SF_Common)
  55     return getCommonSymbolSize(Ref);
  56   return getSymbolValueImpl(Ref);
  57 }
  58
  59 Error ObjectFile::printSymbolName(raw_ostream &OS, DataRefImpl Symb) const {
  60   Expected<StringRef> Name = getSymbolName(Symb);
  61   if (!Name)
  62     return Name.takeError();
  63   OS << *Name;
  64   return Error::success();
  65 }
  66
  67 uint32_t ObjectFile::getSymbolAlignment(DataRefImpl DRI) const { return 0; }
  68
  69 bool ObjectFile::isSectionBitcode(DataRefImpl Sec) const {
  70   Expected<StringRef> NameOrErr = getSectionName(Sec);
  71   if (NameOrErr)
  72     return *NameOrErr == ".llvmbc";
  73   consumeError(NameOrErr.takeError());
  74   return false;
  75 }
  76
  77 bool ObjectFile::isSectionStripped(DataRefImpl Sec) const { return false; }
  78
  79 bool ObjectFile::isBerkeleyText(DataRefImpl Sec) const {
  80   return isSectionText(Sec);
  81 }
  82
  83 bool ObjectFile::isBerkeleyData(DataRefImpl Sec) const {
  84   return isSectionData(Sec);
  85 }
  86
  87 Expected<section_iterator>
  88 ObjectFile::getRelocatedSection(DataRefImpl Sec) const {
  89   return section_iterator(SectionRef(Sec, this));
  90 }
  91
  92 Triple ObjectFile::makeTriple() const {
  93   Triple TheTriple;
  94   auto Arch = getArch();
  95   TheTriple.setArch(Triple::ArchType(Arch));
  96
  97   // For ARM targets, try to use the build attributes to build determine
  98   // the build target. Target features are also added, but later during
  99   // disassembly.
 100   if (Arch == Triple::arm || Arch == Triple::armeb)
 101     setARMSubArch(TheTriple);
 102
 103   // TheTriple defaults to ELF, and COFF doesn't have an environment:
 104   // the best we can do here is indicate that it is mach-o.
 105   if (isMachO())
 106     TheTriple.setObjectFormat(Triple::MachO);
 107
 108   if (isCOFF()) {
 109     const auto COFFObj = cast<COFFObjectFile>(this);
 110     if (COFFObj->getArch() == Triple::thumb)
 111       TheTriple.setTriple("thumbv7-windows");
 112   }
 113
 114   return TheTriple;
 115 }
 116
 117 Expected<std::unique_ptr<ObjectFile>>
 118 ObjectFile::createObjectFile(MemoryBufferRef Object, file_magic Type) {
 119   StringRef Data = Object.getBuffer();
 120   if (Type == file_magic::unknown)
 121     Type = identify_magic(Data);
 122
 123   switch (Type) {
 124   case file_magic::unknown:
 125   case file_magic::bitcode:
 126   case file_magic::coff_cl_gl_object:
 127   case file_magic::archive:
 128   case file_magic::macho_universal_binary:
 129   case file_magic::windows_resource:
 130   case file_magic::pdb:
 131   case file_magic::minidump:
 132     return errorCodeToError(object_error::invalid_file_type);
 133   case file_magic::tapi_file:
 134     return errorCodeToError(object_error::invalid_file_type);
 135   case file_magic::elf:
 136   case file_magic::elf_relocatable:
 137   case file_magic::elf_executable:
 138   case file_magic::elf_shared_object:
 139   case file_magic::elf_core:
 140     return createELFObjectFile(Object);
 141   case file_magic::macho_object:
 142   case file_magic::macho_executable:
 143   case file_magic::macho_fixed_virtual_memory_shared_lib:
 144   case file_magic::macho_core:
 145   case file_magic::macho_preload_executable:
 146   case file_magic::macho_dynamically_linked_shared_lib:
 147   case file_magic::macho_dynamic_linker:
 148   case file_magic::macho_bundle:
 149   case file_magic::macho_dynamically_linked_shared_lib_stub:
 150   case file_magic::macho_dsym_companion:
 151   case file_magic::macho_kext_bundle:
 152     return createMachOObjectFile(Object);
 153   case file_magic::coff_object:
 154   case file_magic::coff_import_library:
 155   case file_magic::pecoff_executable:
 156     return createCOFFObjectFile(Object);
 157   case file_magic::xcoff_object_32:
 158     return createXCOFFObjectFile(Object, Binary::ID_XCOFF32);
 159   case file_magic::xcoff_object_64:
 160     return createXCOFFObjectFile(Object, Binary::ID_XCOFF64);
 161   case file_magic::wasm_object:
 162     return createWasmObjectFile(Object);
 163   }
 164   llvm_unreachable("Unexpected Object File Type");
 165 }
 166
 167 Expected<OwningBinary<ObjectFile>>
 168 ObjectFile::createObjectFile(StringRef ObjectPath) {
 169   ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
 170       MemoryBuffer::getFile(ObjectPath);
 171   if (std::error_code EC = FileOrErr.getError())
 172     return errorCodeToError(EC);
 173   std::unique_ptr<MemoryBuffer> Buffer = std::move(FileOrErr.get());
 174
 175   Expected<std::unique_ptr<ObjectFile>> ObjOrErr =
 176       createObjectFile(Buffer->getMemBufferRef());
 177   if (Error Err = ObjOrErr.takeError())
 178     return std::move(Err);
 179   std::unique_ptr<ObjectFile> Obj = std::move(ObjOrErr.get());
 180
 181   return OwningBinary<ObjectFile>(std::move(Obj), std::move(Buffer));
 182 }