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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/MCLDInput.h>
15 #include <mcld/Support/MemoryRegion.h>
16 #include <mcld/Target/GNULDBackend.h>
17 
18 #include <llvm/ADT/Twine.h>
19 #include <llvm/ADT/OwningPtr.h>
20 #include <llvm/Support/ErrorHandling.h>
21 
22 #include <string>
23 
24 using namespace mcld;
25 
26 //===----------------------------------------------------------------------===//
27 // ELFDynObjReader
28 //===----------------------------------------------------------------------===//
ELFDynObjReader(GNULDBackend & pBackend,IRBuilder & pBuilder,const LinkerConfig & pConfig)29 ELFDynObjReader::ELFDynObjReader(GNULDBackend& pBackend,
30                                  IRBuilder& pBuilder,
31                                  const LinkerConfig& pConfig)
32   : DynObjReader(),
33     m_pELFReader(0),
34     m_Builder(pBuilder) {
35   if (pConfig.targets().is32Bits() && pConfig.targets().isLittleEndian())
36     m_pELFReader = new ELFReader<32, true>(pBackend);
37   else if (pConfig.targets().is64Bits() && pConfig.targets().isLittleEndian())
38     m_pELFReader = new ELFReader<64, true>(pBackend);
39 }
40 
~ELFDynObjReader()41 ELFDynObjReader::~ELFDynObjReader()
42 {
43   delete m_pELFReader;
44 }
45 
46 /// isMyFormat
isMyFormat(Input & pInput) const47 bool ELFDynObjReader::isMyFormat(Input &pInput) const
48 {
49   assert(pInput.hasMemArea());
50 
51   // Don't warning about the frequently requests.
52   // MemoryArea has a list of cache to handle this.
53   size_t hdr_size = m_pELFReader->getELFHeaderSize();
54   MemoryRegion* region = pInput.memArea()->request(pInput.fileOffset(),
55                                                    hdr_size);
56 
57   uint8_t* ELF_hdr = region->start();
58   bool result = true;
59   if (!m_pELFReader->isELF(ELF_hdr))
60     result = false;
61   else if (!m_pELFReader->isMyEndian(ELF_hdr))
62     result = false;
63   else if (!m_pELFReader->isMyMachine(ELF_hdr))
64     result = false;
65   else if (Input::DynObj != m_pELFReader->fileType(ELF_hdr))
66     result = false;
67   pInput.memArea()->release(region);
68   return result;
69 }
70 
71 /// readHeader
readHeader(Input & pInput)72 bool ELFDynObjReader::readHeader(Input& pInput)
73 {
74   assert(pInput.hasMemArea());
75 
76   size_t hdr_size = m_pELFReader->getELFHeaderSize();
77   MemoryRegion* region = pInput.memArea()->request(pInput.fileOffset(),
78                                                    hdr_size);
79   uint8_t* ELF_hdr = region->start();
80 
81   bool shdr_result = m_pELFReader->readSectionHeaders(pInput, ELF_hdr);
82   pInput.memArea()->release(region);
83 
84   // read .dynamic to get the correct SONAME
85   bool dyn_result = m_pELFReader->readDynamic(pInput);
86 
87   return (shdr_result && dyn_result);
88 }
89 
90 /// readSymbols
readSymbols(Input & pInput)91 bool ELFDynObjReader::readSymbols(Input& pInput)
92 {
93   assert(pInput.hasMemArea());
94 
95   LDSection* symtab_shdr = pInput.context()->getSection(".dynsym");
96   if (NULL == symtab_shdr) {
97     note(diag::note_has_no_symtab) << pInput.name()
98                                    << pInput.path()
99                                    << ".dynsym";
100     return true;
101   }
102 
103   LDSection* strtab_shdr = symtab_shdr->getLink();
104   if (NULL == strtab_shdr) {
105     fatal(diag::fatal_cannot_read_strtab) << pInput.name()
106                                           << pInput.path()
107                                           << ".dynsym";
108     return false;
109   }
110 
111   MemoryRegion* symtab_region = pInput.memArea()->request(
112               pInput.fileOffset() + symtab_shdr->offset(), symtab_shdr->size());
113 
114   MemoryRegion* strtab_region = pInput.memArea()->request(
115               pInput.fileOffset() + strtab_shdr->offset(), strtab_shdr->size());
116   char* strtab = reinterpret_cast<char*>(strtab_region->start());
117   bool result = m_pELFReader->readSymbols(pInput, m_Builder,
118                                           *symtab_region, strtab);
119   pInput.memArea()->release(symtab_region);
120   pInput.memArea()->release(strtab_region);
121 
122   return result;
123 }
124 
125