ELFDynObjReader.cpp revision f33f6de54db174aa679a4b6d1e040d37e95541c0 
1//===- ELFDynObjReader.cpp ------------------------------------------------===//
2//
3//                     The MCLinker Project
4//
5// This file is distributed under the University of Illinois Open Source
6// License. See LICENSE.TXT for details.
7//
8//===----------------------------------------------------------------------===//
9#include <mcld/LD/ELFDynObjReader.h>
10
11#include <mcld/LinkerConfig.h>
12#include <mcld/IRBuilder.h>
13#include <mcld/LD/ELFReader.h>
14#include <mcld/MC/Input.h>
15#include <mcld/Target/GNULDBackend.h>
16#include <mcld/Support/MemoryArea.h>
17
18#include <llvm/ADT/StringRef.h>
19#include <llvm/ADT/Twine.h>
20#include <llvm/ADT/OwningPtr.h>
21#include <llvm/Support/ErrorHandling.h>
22
23#include <string>
24
25using namespace mcld;
26
27//===----------------------------------------------------------------------===//
28// ELFDynObjReader
29//===----------------------------------------------------------------------===//
30ELFDynObjReader::ELFDynObjReader(GNULDBackend& pBackend,
31                                 IRBuilder& pBuilder,
32                                 const LinkerConfig& pConfig)
33  : DynObjReader(),
34    m_pELFReader(0),
35    m_Builder(pBuilder) {
36  if (pConfig.targets().is32Bits() && pConfig.targets().isLittleEndian())
37    m_pELFReader = new ELFReader<32, true>(pBackend);
38  else if (pConfig.targets().is64Bits() && pConfig.targets().isLittleEndian())
39    m_pELFReader = new ELFReader<64, true>(pBackend);
40}
41
42ELFDynObjReader::~ELFDynObjReader()
43{
44  delete m_pELFReader;
45}
46
47/// isMyFormat
48bool ELFDynObjReader::isMyFormat(Input &pInput, bool &pContinue) const
49{
50  assert(pInput.hasMemArea());
51
52  // Don't warning about the frequently requests.
53  // MemoryArea has a list of cache to handle this.
54  size_t hdr_size = m_pELFReader->getELFHeaderSize();
55  if (pInput.memArea()->size() < hdr_size)
56    return false;
57
58  llvm::StringRef region = pInput.memArea()->request(pInput.fileOffset(),
59                                                     hdr_size);
60
61  const char* ELF_hdr = region.begin();
62  bool result = true;
63  if (!m_pELFReader->isELF(ELF_hdr)) {
64    pContinue = true;
65    result = false;
66  } else if (Input::DynObj != m_pELFReader->fileType(ELF_hdr)) {
67    pContinue = true;
68    result = false;
69  } else if (!m_pELFReader->isMyEndian(ELF_hdr)) {
70    pContinue = false;
71    result = false;
72  } else if (!m_pELFReader->isMyMachine(ELF_hdr)) {
73    pContinue = false;
74    result = false;
75  }
76  return result;
77}
78
79/// readHeader
80bool ELFDynObjReader::readHeader(Input& pInput)
81{
82  assert(pInput.hasMemArea());
83
84  size_t hdr_size = m_pELFReader->getELFHeaderSize();
85  llvm::StringRef region = pInput.memArea()->request(pInput.fileOffset(),
86                                                     hdr_size);
87  const char* ELF_hdr = region.begin();
88
89  bool shdr_result = m_pELFReader->readSectionHeaders(pInput, ELF_hdr);
90
91  // read .dynamic to get the correct SONAME
92  bool dyn_result = m_pELFReader->readDynamic(pInput);
93
94  return (shdr_result && dyn_result);
95}
96
97/// readSymbols
98bool ELFDynObjReader::readSymbols(Input& pInput)
99{
100  assert(pInput.hasMemArea());
101
102  LDSection* symtab_shdr = pInput.context()->getSection(".dynsym");
103  if (NULL == symtab_shdr) {
104    note(diag::note_has_no_symtab) << pInput.name()
105                                   << pInput.path()
106                                   << ".dynsym";
107    return true;
108  }
109
110  LDSection* strtab_shdr = symtab_shdr->getLink();
111  if (NULL == strtab_shdr) {
112    fatal(diag::fatal_cannot_read_strtab) << pInput.name()
113                                          << pInput.path()
114                                          << ".dynsym";
115    return false;
116  }
117
118  llvm::StringRef symtab_region = pInput.memArea()->request(
119      pInput.fileOffset() + symtab_shdr->offset(), symtab_shdr->size());
120
121  llvm::StringRef strtab_region = pInput.memArea()->request(
122      pInput.fileOffset() + strtab_shdr->offset(), strtab_shdr->size());
123  const char* strtab = strtab_region.begin();
124  bool result = m_pELFReader->readSymbols(pInput, m_Builder,
125                                          symtab_region, strtab);
126  return result;
127}
128
129