ObjectFile.cpp revision 341825 
1//===- ObjectFile.cpp - File format independent object file ---------------===//
2//
3//                     The LLVM Compiler Infrastructure
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9//
10// This file defines a file format independent ObjectFile class.
11//
12//===----------------------------------------------------------------------===//
13
14#include "llvm/Object/ObjectFile.h"
15#include "llvm/ADT/StringRef.h"
16#include "llvm/BinaryFormat/Magic.h"
17#include "llvm/Object/Binary.h"
18#include "llvm/Object/COFF.h"
19#include "llvm/Object/Error.h"
20#include "llvm/Object/MachO.h"
21#include "llvm/Object/Wasm.h"
22#include "llvm/Support/Error.h"
23#include "llvm/Support/ErrorHandling.h"
24#include "llvm/Support/ErrorOr.h"
25#include "llvm/Support/FileSystem.h"
26#include "llvm/Support/MemoryBuffer.h"
27#include "llvm/Support/raw_ostream.h"
28#include <algorithm>
29#include <cstdint>
30#include <memory>
31#include <system_error>
32
33using namespace llvm;
34using namespace object;
35
36void ObjectFile::anchor() {}
37
38ObjectFile::ObjectFile(unsigned int Type, MemoryBufferRef Source)
39    : SymbolicFile(Type, Source) {}
40
41bool SectionRef::containsSymbol(SymbolRef S) const {
42  Expected<section_iterator> SymSec = S.getSection();
43  if (!SymSec) {
44    // TODO: Actually report errors helpfully.
45    consumeError(SymSec.takeError());
46    return false;
47  }
48  return *this == **SymSec;
49}
50
51uint64_t ObjectFile::getSymbolValue(DataRefImpl Ref) const {
52  uint32_t Flags = getSymbolFlags(Ref);
53  if (Flags & SymbolRef::SF_Undefined)
54    return 0;
55  if (Flags & SymbolRef::SF_Common)
56    return getCommonSymbolSize(Ref);
57  return getSymbolValueImpl(Ref);
58}
59
60std::error_code ObjectFile::printSymbolName(raw_ostream &OS,
61                                            DataRefImpl Symb) const {
62  Expected<StringRef> Name = getSymbolName(Symb);
63  if (!Name)
64    return errorToErrorCode(Name.takeError());
65  OS << *Name;
66  return std::error_code();
67}
68
69uint32_t ObjectFile::getSymbolAlignment(DataRefImpl DRI) const { return 0; }
70
71bool ObjectFile::isSectionBitcode(DataRefImpl Sec) const {
72  StringRef SectName;
73  if (!getSectionName(Sec, SectName))
74    return SectName == ".llvmbc";
75  return false;
76}
77
78bool ObjectFile::isSectionStripped(DataRefImpl Sec) const { return false; }
79
80section_iterator ObjectFile::getRelocatedSection(DataRefImpl Sec) const {
81  return section_iterator(SectionRef(Sec, this));
82}
83
84Triple ObjectFile::makeTriple() const {
85  Triple TheTriple;
86  auto Arch = getArch();
87  TheTriple.setArch(Triple::ArchType(Arch));
88
89  // For ARM targets, try to use the build attributes to build determine
90  // the build target. Target features are also added, but later during
91  // disassembly.
92  if (Arch == Triple::arm || Arch == Triple::armeb)
93    setARMSubArch(TheTriple);
94
95  // TheTriple defaults to ELF, and COFF doesn't have an environment:
96  // the best we can do here is indicate that it is mach-o.
97  if (isMachO())
98    TheTriple.setObjectFormat(Triple::MachO);
99
100  if (isCOFF()) {
101    const auto COFFObj = dyn_cast<COFFObjectFile>(this);
102    if (COFFObj->getArch() == Triple::thumb)
103      TheTriple.setTriple("thumbv7-windows");
104  }
105
106  return TheTriple;
107}
108
109Expected<std::unique_ptr<ObjectFile>>
110ObjectFile::createObjectFile(MemoryBufferRef Object, file_magic Type) {
111  StringRef Data = Object.getBuffer();
112  if (Type == file_magic::unknown)
113    Type = identify_magic(Data);
114
115  switch (Type) {
116  case file_magic::unknown:
117  case file_magic::bitcode:
118  case file_magic::coff_cl_gl_object:
119  case file_magic::archive:
120  case file_magic::macho_universal_binary:
121  case file_magic::windows_resource:
122  case file_magic::pdb:
123    return errorCodeToError(object_error::invalid_file_type);
124  case file_magic::elf:
125  case file_magic::elf_relocatable:
126  case file_magic::elf_executable:
127  case file_magic::elf_shared_object:
128  case file_magic::elf_core:
129    return createELFObjectFile(Object);
130  case file_magic::macho_object:
131  case file_magic::macho_executable:
132  case file_magic::macho_fixed_virtual_memory_shared_lib:
133  case file_magic::macho_core:
134  case file_magic::macho_preload_executable:
135  case file_magic::macho_dynamically_linked_shared_lib:
136  case file_magic::macho_dynamic_linker:
137  case file_magic::macho_bundle:
138  case file_magic::macho_dynamically_linked_shared_lib_stub:
139  case file_magic::macho_dsym_companion:
140  case file_magic::macho_kext_bundle:
141    return createMachOObjectFile(Object);
142  case file_magic::coff_object:
143  case file_magic::coff_import_library:
144  case file_magic::pecoff_executable:
145    return createCOFFObjectFile(Object);
146  case file_magic::wasm_object:
147    return createWasmObjectFile(Object);
148  }
149  llvm_unreachable("Unexpected Object File Type");
150}
151
152Expected<OwningBinary<ObjectFile>>
153ObjectFile::createObjectFile(StringRef ObjectPath) {
154  ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
155      MemoryBuffer::getFile(ObjectPath);
156  if (std::error_code EC = FileOrErr.getError())
157    return errorCodeToError(EC);
158  std::unique_ptr<MemoryBuffer> Buffer = std::move(FileOrErr.get());
159
160  Expected<std::unique_ptr<ObjectFile>> ObjOrErr =
161      createObjectFile(Buffer->getMemBufferRef());
162  if (Error Err = ObjOrErr.takeError())
163    return std::move(Err);
164  std::unique_ptr<ObjectFile> Obj = std::move(ObjOrErr.get());
165
166  return OwningBinary<ObjectFile>(std::move(Obj), std::move(Buffer));
167}
168