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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/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/Support/ErrorHandling.h>
     21 
     22 #include <string>
     23 
     24 using namespace mcld;
     25 
     26 //===----------------------------------------------------------------------===//
     27 // ELFDynObjReader
     28 //===----------------------------------------------------------------------===//
     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 
     41 ELFDynObjReader::~ELFDynObjReader()
     42 {
     43   delete m_pELFReader;
     44 }
     45 
     46 /// isMyFormat
     47 bool ELFDynObjReader::isMyFormat(Input &pInput, bool &pContinue) 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   if (pInput.memArea()->size() < hdr_size)
     55     return false;
     56 
     57   llvm::StringRef region = pInput.memArea()->request(pInput.fileOffset(),
     58                                                      hdr_size);
     59 
     60   const char* ELF_hdr = region.begin();
     61   bool result = true;
     62   if (!m_pELFReader->isELF(ELF_hdr)) {
     63     pContinue = true;
     64     result = false;
     65   } else if (Input::DynObj != m_pELFReader->fileType(ELF_hdr)) {
     66     pContinue = true;
     67     result = false;
     68   } else if (!m_pELFReader->isMyEndian(ELF_hdr)) {
     69     pContinue = false;
     70     result = false;
     71   } else if (!m_pELFReader->isMyMachine(ELF_hdr)) {
     72     pContinue = false;
     73     result = false;
     74   }
     75   return result;
     76 }
     77 
     78 /// readHeader
     79 bool ELFDynObjReader::readHeader(Input& pInput)
     80 {
     81   assert(pInput.hasMemArea());
     82 
     83   size_t hdr_size = m_pELFReader->getELFHeaderSize();
     84   llvm::StringRef region = pInput.memArea()->request(pInput.fileOffset(),
     85                                                      hdr_size);
     86   const char* ELF_hdr = region.begin();
     87 
     88   bool shdr_result = m_pELFReader->readSectionHeaders(pInput, ELF_hdr);
     89 
     90   // read .dynamic to get the correct SONAME
     91   bool dyn_result = m_pELFReader->readDynamic(pInput);
     92 
     93   return (shdr_result && dyn_result);
     94 }
     95 
     96 /// readSymbols
     97 bool ELFDynObjReader::readSymbols(Input& pInput)
     98 {
     99   assert(pInput.hasMemArea());
    100 
    101   LDSection* symtab_shdr = pInput.context()->getSection(".dynsym");
    102   if (NULL == symtab_shdr) {
    103     note(diag::note_has_no_symtab) << pInput.name()
    104                                    << pInput.path()
    105                                    << ".dynsym";
    106     return true;
    107   }
    108 
    109   LDSection* strtab_shdr = symtab_shdr->getLink();
    110   if (NULL == strtab_shdr) {
    111     fatal(diag::fatal_cannot_read_strtab) << pInput.name()
    112                                           << pInput.path()
    113                                           << ".dynsym";
    114     return false;
    115   }
    116 
    117   llvm::StringRef symtab_region = pInput.memArea()->request(
    118       pInput.fileOffset() + symtab_shdr->offset(), symtab_shdr->size());
    119 
    120   llvm::StringRef strtab_region = pInput.memArea()->request(
    121       pInput.fileOffset() + strtab_shdr->offset(), strtab_shdr->size());
    122   const char* strtab = strtab_region.begin();
    123   bool result = m_pELFReader->readSymbols(pInput, m_Builder,
    124                                           symtab_region, strtab);
    125   return result;
    126 }
    127 
    128