bool ARMGNULDBackend::readSection(Input& pInput,
MCLinker& pLinker,
LDSection& pInputSectHdr)
{
LDSection& out_sect = pLinker.getOrCreateOutputSectHdr(pInputSectHdr.name(),
pInputSectHdr.kind(),
pInputSectHdr.type(),
pInputSectHdr.flag());
// FIXME: (Luba)
// Handle ARM attributes in the right way.
// In current milestone, MCLinker goes through the shortcut.
// It reads input's ARM attributes and copies the first ARM attributes
// into the output file. The correct way is merge these sections, not
// just copy.
if ((0 == out_sect.name().compare(".ARM.attributes")) &&
(0 != out_sect.size()))
return true;
MemoryRegion* region = pInput.memArea()->request(pInputSectHdr.offset(),
pInputSectHdr.size());
llvm::MCSectionData& sect_data = pLinker.getOrCreateSectData(pInputSectHdr);
new MCRegionFragment(*region, §_data);
out_sect.setSize(out_sect.size() + pInputSectHdr.size());
return true;
}
void ARMGNULDBackend::createARMGOT(MCLinker& pLinker, const Output& pOutput)
{
// get .got LDSection and create MCSectionData
ELFFileFormat* file_format = getOutputFormat(pOutput);
LDSection& got = file_format->getGOT();
m_pGOT = new ARMGOT(got, pLinker.getOrCreateSectData(got));
// define symbol _GLOBAL_OFFSET_TABLE_ when .got create
if( m_pGOTSymbol != NULL ) {
pLinker.defineSymbol<MCLinker::Force, MCLinker::Unresolve>(
"_GLOBAL_OFFSET_TABLE_",
false,
ResolveInfo::Object,
ResolveInfo::Define,
ResolveInfo::Local,
0x0, // size
0x0, // value
pLinker.getLayout().getFragmentRef(*(m_pGOT->begin()), 0x0),
ResolveInfo::Hidden);
}
else {
m_pGOTSymbol = pLinker.defineSymbol<MCLinker::Force, MCLinker::Resolve>(
"_GLOBAL_OFFSET_TABLE_",
false,
ResolveInfo::Object,
ResolveInfo::Define,
ResolveInfo::Local,
0x0, // size
0x0, // value
pLinker.getLayout().getFragmentRef(*(m_pGOT->begin()), 0x0),
ResolveInfo::Hidden);
}
}
void ARMGNULDBackend::createARMPLTandRelPLT(MCLinker& pLinker,
const Output& pOutput)
{
ELFFileFormat* file_format = getOutputFormat(pOutput);
// get .plt and .rel.plt LDSection
LDSection& plt = file_format->getPLT();
LDSection& relplt = file_format->getRelPlt();
// create MCSectionData and ARMPLT
m_pPLT = new ARMPLT(plt, pLinker.getOrCreateSectData(plt), *m_pGOT);
// set info of .rel.plt to .plt
relplt.setLink(&plt);
// create MCSectionData and ARMRelDynSection
m_pRelPLT = new OutputRelocSection(relplt,
pLinker.getOrCreateSectData(relplt),
8);
}
void ARMGNULDBackend::createARMRelDyn(MCLinker& pLinker,
const Output& pOutput)
{
ELFFileFormat* file_format = getOutputFormat(pOutput);
// get .rel.dyn LDSection and create MCSectionData
LDSection& reldyn = file_format->getRelDyn();
// create MCSectionData and ARMRelDynSection
m_pRelDyn = new OutputRelocSection(reldyn,
pLinker.getOrCreateSectData(reldyn),
8);
}
/// allocateCommonSymbols - allocate common symbols in the corresponding
/// sections.
/// @refer Google gold linker: common.cc: 214
bool
ARMGNULDBackend::allocateCommonSymbols(const MCLDInfo& pInfo, MCLinker& pLinker) const
{
SymbolCategory& symbol_list = pLinker.getOutputSymbols();
if (symbol_list.emptyCommons() && symbol_list.emptyLocals())
return true;
// addralign := max value of all common symbols
uint64_t addralign = 0x0;
// Due to the visibility, some common symbols may be forcefully local.
SymbolCategory::iterator com_sym, com_end = symbol_list.localEnd();
for (com_sym = symbol_list.localBegin(); com_sym != com_end; ++com_sym) {
if (ResolveInfo::Common == (*com_sym)->desc()) {
if ((*com_sym)->value() > addralign)
addralign = (*com_sym)->value();
}
}
// global common symbols.
com_end = symbol_list.commonEnd();
for (com_sym = symbol_list.commonBegin(); com_sym != com_end; ++com_sym) {
if ((*com_sym)->value() > addralign)
addralign = (*com_sym)->value();
}
// FIXME: If the order of common symbols is defined, then sort common symbols
// com_sym = symbol_list.commonBegin();
// std::sort(com_sym, com_end, some kind of order);
// get or create corresponding BSS LDSection
LDSection* bss_sect_hdr = NULL;
if (ResolveInfo::ThreadLocal == (*com_sym)->type()) {
bss_sect_hdr = &pLinker.getOrCreateOutputSectHdr(
".tbss",
LDFileFormat::BSS,
llvm::ELF::SHT_NOBITS,
llvm::ELF::SHF_WRITE | llvm::ELF::SHF_ALLOC);
}
else {
bss_sect_hdr = &pLinker.getOrCreateOutputSectHdr(".bss",
LDFileFormat::BSS,
llvm::ELF::SHT_NOBITS,
llvm::ELF::SHF_WRITE | llvm::ELF::SHF_ALLOC);
}
// get or create corresponding BSS MCSectionData
assert(NULL != bss_sect_hdr);
llvm::MCSectionData& bss_section = pLinker.getOrCreateSectData(*bss_sect_hdr);
// allocate all common symbols
uint64_t offset = bss_sect_hdr->size();
// allocate all local common symbols
com_end = symbol_list.localEnd();
for (com_sym = symbol_list.localBegin(); com_sym != com_end; ++com_sym) {
if (ResolveInfo::Common == (*com_sym)->desc()) {
// We have to reset the description of the symbol here. When doing
// incremental linking, the output relocatable object may have common
// symbols. Therefore, we can not treat common symbols as normal symbols
// when emitting the regular name pools. We must change the symbols'
// description here.
(*com_sym)->resolveInfo()->setDesc(ResolveInfo::Define);
llvm::MCFragment* frag = new llvm::MCFillFragment(0x0, 1, (*com_sym)->size());
(*com_sym)->setFragmentRef(new MCFragmentRef(*frag, 0));
uint64_t size = pLinker.getLayout().appendFragment(*frag,
bss_section,
(*com_sym)->value());
offset += size;
}
}
// allocate all global common symbols
com_end = symbol_list.commonEnd();
for (com_sym = symbol_list.commonBegin(); com_sym != com_end; ++com_sym) {
// We have to reset the description of the symbol here. When doing
// incremental linking, the output relocatable object may have common
// symbols. Therefore, we can not treat common symbols as normal symbols
// when emitting the regular name pools. We must change the symbols'
// description here.
(*com_sym)->resolveInfo()->setDesc(ResolveInfo::Define);
llvm::MCFragment* frag = new llvm::MCFillFragment(0x0, 1, (*com_sym)->size());
(*com_sym)->setFragmentRef(new MCFragmentRef(*frag, 0));
uint64_t size = pLinker.getLayout().appendFragment(*frag,
bss_section,
(*com_sym)->value());
offset += size;
}
bss_sect_hdr->setSize(offset);
symbol_list.changeCommonsToGlobal();
return true;
}