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      1 //===- ObjectFile.cpp - File format independent object file -----*- C++ -*-===//
      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/COFF.h"
     15 #include "llvm/Object/MachO.h"
     16 #include "llvm/Object/ObjectFile.h"
     17 #include "llvm/Support/ErrorHandling.h"
     18 #include "llvm/Support/FileSystem.h"
     19 #include "llvm/Support/MemoryBuffer.h"
     20 #include "llvm/Support/raw_ostream.h"
     21 #include <system_error>
     22 
     23 using namespace llvm;
     24 using namespace object;
     25 
     26 void ObjectFile::anchor() { }
     27 
     28 ObjectFile::ObjectFile(unsigned int Type, MemoryBufferRef Source)
     29     : SymbolicFile(Type, Source) {}
     30 
     31 bool SectionRef::containsSymbol(SymbolRef S) const {
     32   Expected<section_iterator> SymSec = S.getSection();
     33   if (!SymSec) {
     34     // TODO: Actually report errors helpfully.
     35     consumeError(SymSec.takeError());
     36     return false;
     37   }
     38   return *this == **SymSec;
     39 }
     40 
     41 uint64_t ObjectFile::getSymbolValue(DataRefImpl Ref) const {
     42   uint32_t Flags = getSymbolFlags(Ref);
     43   if (Flags & SymbolRef::SF_Undefined)
     44     return 0;
     45   if (Flags & SymbolRef::SF_Common)
     46     return getCommonSymbolSize(Ref);
     47   return getSymbolValueImpl(Ref);
     48 }
     49 
     50 std::error_code ObjectFile::printSymbolName(raw_ostream &OS,
     51                                             DataRefImpl Symb) const {
     52   Expected<StringRef> Name = getSymbolName(Symb);
     53   if (!Name)
     54     return errorToErrorCode(Name.takeError());
     55   OS << *Name;
     56   return std::error_code();
     57 }
     58 
     59 uint32_t ObjectFile::getSymbolAlignment(DataRefImpl DRI) const { return 0; }
     60 
     61 bool ObjectFile::isSectionBitcode(DataRefImpl Sec) const {
     62   StringRef SectName;
     63   if (!getSectionName(Sec, SectName))
     64     return SectName == ".llvmbc";
     65   return false;
     66 }
     67 
     68 section_iterator ObjectFile::getRelocatedSection(DataRefImpl Sec) const {
     69   return section_iterator(SectionRef(Sec, this));
     70 }
     71 
     72 Expected<std::unique_ptr<ObjectFile>>
     73 ObjectFile::createObjectFile(MemoryBufferRef Object, sys::fs::file_magic Type) {
     74   StringRef Data = Object.getBuffer();
     75   if (Type == sys::fs::file_magic::unknown)
     76     Type = sys::fs::identify_magic(Data);
     77 
     78   switch (Type) {
     79   case sys::fs::file_magic::unknown:
     80   case sys::fs::file_magic::bitcode:
     81   case sys::fs::file_magic::archive:
     82   case sys::fs::file_magic::macho_universal_binary:
     83   case sys::fs::file_magic::windows_resource:
     84     return errorCodeToError(object_error::invalid_file_type);
     85   case sys::fs::file_magic::elf:
     86   case sys::fs::file_magic::elf_relocatable:
     87   case sys::fs::file_magic::elf_executable:
     88   case sys::fs::file_magic::elf_shared_object:
     89   case sys::fs::file_magic::elf_core:
     90     return errorOrToExpected(createELFObjectFile(Object));
     91   case sys::fs::file_magic::macho_object:
     92   case sys::fs::file_magic::macho_executable:
     93   case sys::fs::file_magic::macho_fixed_virtual_memory_shared_lib:
     94   case sys::fs::file_magic::macho_core:
     95   case sys::fs::file_magic::macho_preload_executable:
     96   case sys::fs::file_magic::macho_dynamically_linked_shared_lib:
     97   case sys::fs::file_magic::macho_dynamic_linker:
     98   case sys::fs::file_magic::macho_bundle:
     99   case sys::fs::file_magic::macho_dynamically_linked_shared_lib_stub:
    100   case sys::fs::file_magic::macho_dsym_companion:
    101   case sys::fs::file_magic::macho_kext_bundle:
    102     return createMachOObjectFile(Object);
    103   case sys::fs::file_magic::coff_object:
    104   case sys::fs::file_magic::coff_import_library:
    105   case sys::fs::file_magic::pecoff_executable:
    106     return errorOrToExpected(createCOFFObjectFile(Object));
    107   }
    108   llvm_unreachable("Unexpected Object File Type");
    109 }
    110 
    111 Expected<OwningBinary<ObjectFile>>
    112 ObjectFile::createObjectFile(StringRef ObjectPath) {
    113   ErrorOr<std::unique_ptr<MemoryBuffer>> FileOrErr =
    114       MemoryBuffer::getFile(ObjectPath);
    115   if (std::error_code EC = FileOrErr.getError())
    116     return errorCodeToError(EC);
    117   std::unique_ptr<MemoryBuffer> Buffer = std::move(FileOrErr.get());
    118 
    119   Expected<std::unique_ptr<ObjectFile>> ObjOrErr =
    120       createObjectFile(Buffer->getMemBufferRef());
    121   if (!ObjOrErr)
    122     ObjOrErr.takeError();
    123   std::unique_ptr<ObjectFile> Obj = std::move(ObjOrErr.get());
    124 
    125   return OwningBinary<ObjectFile>(std::move(Obj), std::move(Buffer));
    126 }
    127