ObjectFile.cpp revision 360784 
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
32using namespace llvm;
33using namespace object;
34
35raw_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
42void ObjectFile::anchor() {}
43
44ObjectFile::ObjectFile(unsigned int Type, MemoryBufferRef Source)
45    : SymbolicFile(Type, Source) {}
46
47bool 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
57uint64_t ObjectFile::getSymbolValue(DataRefImpl Ref) const {
58  uint32_t Flags = getSymbolFlags(Ref);
59  if (Flags & SymbolRef::SF_Undefined)
60    return 0;
61  if (Flags & SymbolRef::SF_Common)
62    return getCommonSymbolSize(Ref);
63  return getSymbolValueImpl(Ref);
64}
65
66Error ObjectFile::printSymbolName(raw_ostream &OS, DataRefImpl Symb) const {
67  Expected<StringRef> Name = getSymbolName(Symb);
68  if (!Name)
69    return Name.takeError();
70  OS << *Name;
71  return Error::success();
72}
73
74uint32_t ObjectFile::getSymbolAlignment(DataRefImpl DRI) const { return 0; }
75
76bool ObjectFile::isSectionBitcode(DataRefImpl Sec) const {
77  Expected<StringRef> NameOrErr = getSectionName(Sec);
78  if (NameOrErr)
79    return *NameOrErr == ".llvmbc";
80  consumeError(NameOrErr.takeError());
81  return false;
82}
83
84bool ObjectFile::isSectionStripped(DataRefImpl Sec) const { return false; }
85
86bool ObjectFile::isBerkeleyText(DataRefImpl Sec) const {
87  return isSectionText(Sec);
88}
89
90bool ObjectFile::isBerkeleyData(DataRefImpl Sec) const {
91  return isSectionData(Sec);
92}
93
94Expected<section_iterator>
95ObjectFile::getRelocatedSection(DataRefImpl Sec) const {
96  return section_iterator(SectionRef(Sec, this));
97}
98
99Triple ObjectFile::makeTriple() const {
100  Triple TheTriple;
101  auto Arch = getArch();
102  TheTriple.setArch(Triple::ArchType(Arch));
103
104  // For ARM targets, try to use the build attributes to build determine
105  // the build target. Target features are also added, but later during
106  // disassembly.
107  if (Arch == Triple::arm || Arch == Triple::armeb)
108    setARMSubArch(TheTriple);
109
110  // TheTriple defaults to ELF, and COFF doesn't have an environment:
111  // the best we can do here is indicate that it is mach-o.
112  if (isMachO())
113    TheTriple.setObjectFormat(Triple::MachO);
114
115  if (isCOFF()) {
116    const auto COFFObj = cast<COFFObjectFile>(this);
117    if (COFFObj->getArch() == Triple::thumb)
118      TheTriple.setTriple("thumbv7-windows");
119  }
120
121  return TheTriple;
122}
123
124Expected<std::unique_ptr<ObjectFile>>
125ObjectFile::createObjectFile(MemoryBufferRef Object, file_magic Type) {
126  StringRef Data = Object.getBuffer();
127  if (Type == file_magic::unknown)
128    Type = identify_magic(Data);
129
130  switch (Type) {
131  case file_magic::unknown:
132  case file_magic::bitcode:
133  case file_magic::coff_cl_gl_object:
134  case file_magic::archive:
135  case file_magic::macho_universal_binary:
136  case file_magic::windows_resource:
137  case file_magic::pdb:
138  case file_magic::minidump:
139    return errorCodeToError(object_error::invalid_file_type);
140  case file_magic::tapi_file:
141    return errorCodeToError(object_error::invalid_file_type);
142  case file_magic::elf:
143  case file_magic::elf_relocatable:
144  case file_magic::elf_executable:
145  case file_magic::elf_shared_object:
146  case file_magic::elf_core:
147    return createELFObjectFile(Object);
148  case file_magic::macho_object:
149  case file_magic::macho_executable:
150  case file_magic::macho_fixed_virtual_memory_shared_lib:
151  case file_magic::macho_core:
152  case file_magic::macho_preload_executable:
153  case file_magic::macho_dynamically_linked_shared_lib:
154  case file_magic::macho_dynamic_linker:
155  case file_magic::macho_bundle:
156  case file_magic::macho_dynamically_linked_shared_lib_stub:
157  case file_magic::macho_dsym_companion:
158  case file_magic::macho_kext_bundle:
159    return createMachOObjectFile(Object);
160  case file_magic::coff_object:
161  case file_magic::coff_import_library:
162  case file_magic::pecoff_executable:
163    return createCOFFObjectFile(Object);
164  case file_magic::xcoff_object_32:
165    return createXCOFFObjectFile(Object, Binary::ID_XCOFF32);
166  case file_magic::xcoff_object_64:
167    return createXCOFFObjectFile(Object, Binary::ID_XCOFF64);
168  case file_magic::wasm_object:
169    return createWasmObjectFile(Object);
170  }
171  llvm_unreachable("Unexpected Object File Type");
172}
173
174Expected<OwningBinary<ObjectFile>>
175ObjectFile::createObjectFile(StringRef ObjectPath) {
176  ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
177      MemoryBuffer::getFile(ObjectPath);
178  if (std::error_code EC = FileOrErr.getError())
179    return errorCodeToError(EC);
180  std::unique_ptr<MemoryBuffer> Buffer = std::move(FileOrErr.get());
181
182  Expected<std::unique_ptr<ObjectFile>> ObjOrErr =
183      createObjectFile(Buffer->getMemBufferRef());
184  if (Error Err = ObjOrErr.takeError())
185    return std::move(Err);
186  std::unique_ptr<ObjectFile> Obj = std::move(ObjOrErr.get());
187
188  return OwningBinary<ObjectFile>(std::move(Obj), std::move(Buffer));
189}
190