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   if (Expected<StringRef> NameOrErr = getSectionName(Sec))
  71     return *NameOrErr == ".llvmbc";
  72   return false;
  73 }
  74
  75 bool ObjectFile::isSectionStripped(DataRefImpl Sec) const { return false; }
  76
  77 bool ObjectFile::isBerkeleyText(DataRefImpl Sec) const {
  78   return isSectionText(Sec);
  79 }
  80
  81 bool ObjectFile::isBerkeleyData(DataRefImpl Sec) const {
  82   return isSectionData(Sec);
  83 }
  84
  85 section_iterator ObjectFile::getRelocatedSection(DataRefImpl Sec) const {
  86   return section_iterator(SectionRef(Sec, this));
  87 }
  88
  89 Triple ObjectFile::makeTriple() const {
  90   Triple TheTriple;
  91   auto Arch = getArch();
  92   TheTriple.setArch(Triple::ArchType(Arch));
  93
  94   // For ARM targets, try to use the build attributes to build determine
  95   // the build target. Target features are also added, but later during
  96   // disassembly.
  97   if (Arch == Triple::arm || Arch == Triple::armeb)
  98     setARMSubArch(TheTriple);
  99
 100   // TheTriple defaults to ELF, and COFF doesn't have an environment:
 101   // the best we can do here is indicate that it is mach-o.
 102   if (isMachO())
 103     TheTriple.setObjectFormat(Triple::MachO);
 104
 105   if (isCOFF()) {
 106     const auto COFFObj = dyn_cast<COFFObjectFile>(this);
 107     if (COFFObj->getArch() == Triple::thumb)
 108       TheTriple.setTriple("thumbv7-windows");
 109   }
 110
 111   return TheTriple;
 112 }
 113
 114 Expected<std::unique_ptr<ObjectFile>>
 115 ObjectFile::createObjectFile(MemoryBufferRef Object, file_magic Type) {
 116   StringRef Data = Object.getBuffer();
 117   if (Type == file_magic::unknown)
 118     Type = identify_magic(Data);
 119
 120   switch (Type) {
 121   case file_magic::unknown:
 122   case file_magic::bitcode:
 123   case file_magic::coff_cl_gl_object:
 124   case file_magic::archive:
 125   case file_magic::macho_universal_binary:
 126   case file_magic::windows_resource:
 127   case file_magic::pdb:
 128   case file_magic::minidump:
 129     return errorCodeToError(object_error::invalid_file_type);
 130   case file_magic::tapi_file:
 131     return errorCodeToError(object_error::invalid_file_type);
 132   case file_magic::elf:
 133   case file_magic::elf_relocatable:
 134   case file_magic::elf_executable:
 135   case file_magic::elf_shared_object:
 136   case file_magic::elf_core:
 137     return createELFObjectFile(Object);
 138   case file_magic::macho_object:
 139   case file_magic::macho_executable:
 140   case file_magic::macho_fixed_virtual_memory_shared_lib:
 141   case file_magic::macho_core:
 142   case file_magic::macho_preload_executable:
 143   case file_magic::macho_dynamically_linked_shared_lib:
 144   case file_magic::macho_dynamic_linker:
 145   case file_magic::macho_bundle:
 146   case file_magic::macho_dynamically_linked_shared_lib_stub:
 147   case file_magic::macho_dsym_companion:
 148   case file_magic::macho_kext_bundle:
 149     return createMachOObjectFile(Object);
 150   case file_magic::coff_object:
 151   case file_magic::coff_import_library:
 152   case file_magic::pecoff_executable:
 153     return createCOFFObjectFile(Object);
 154   case file_magic::xcoff_object_32:
 155     return createXCOFFObjectFile(Object, Binary::ID_XCOFF32);
 156   case file_magic::xcoff_object_64:
 157     return createXCOFFObjectFile(Object, Binary::ID_XCOFF64);
 158   case file_magic::wasm_object:
 159     return createWasmObjectFile(Object);
 160   }
 161   llvm_unreachable("Unexpected Object File Type");
 162 }
 163
 164 Expected<OwningBinary<ObjectFile>>
 165 ObjectFile::createObjectFile(StringRef ObjectPath) {
 166   ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
 167       MemoryBuffer::getFile(ObjectPath);
 168   if (std::error_code EC = FileOrErr.getError())
 169     return errorCodeToError(EC);
 170   std::unique_ptr<MemoryBuffer> Buffer = std::move(FileOrErr.get());
 171
 172   Expected<std::unique_ptr<ObjectFile>> ObjOrErr =
 173       createObjectFile(Buffer->getMemBufferRef());
 174   if (Error Err = ObjOrErr.takeError())
 175     return std::move(Err);
 176   std::unique_ptr<ObjectFile> Obj = std::move(ObjOrErr.get());
 177
 178   return OwningBinary<ObjectFile>(std::move(Obj), std::move(Buffer));
 179 }