| //===- ELFObjectWriter.cpp ------------------------------------------------===// |
| // |
| // The MCLinker Project |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| #include "mcld/LD/ELFObjectWriter.h" |
| |
| #include "mcld/LinkerConfig.h" |
| #include "mcld/LinkerScript.h" |
| #include "mcld/Module.h" |
| #include "mcld/ADT/SizeTraits.h" |
| #include "mcld/Fragment/AlignFragment.h" |
| #include "mcld/Fragment/FillFragment.h" |
| #include "mcld/Fragment/NullFragment.h" |
| #include "mcld/Fragment/RegionFragment.h" |
| #include "mcld/Fragment/Stub.h" |
| #include "mcld/LD/DebugString.h" |
| #include "mcld/LD/EhFrame.h" |
| #include "mcld/LD/ELFFileFormat.h" |
| #include "mcld/LD/ELFSegment.h" |
| #include "mcld/LD/ELFSegmentFactory.h" |
| #include "mcld/LD/LDSection.h" |
| #include "mcld/LD/LDSymbol.h" |
| #include "mcld/LD/RelocData.h" |
| #include "mcld/LD/SectionData.h" |
| #include "mcld/Support/MsgHandling.h" |
| #include "mcld/Target/GNUInfo.h" |
| #include "mcld/Target/GNULDBackend.h" |
| |
| #include <llvm/Support/Casting.h> |
| #include <llvm/Support/ELF.h> |
| #include <llvm/Support/Errc.h> |
| #include <llvm/Support/ErrorHandling.h> |
| |
| namespace mcld { |
| |
| //===----------------------------------------------------------------------===// |
| // ELFObjectWriter |
| //===----------------------------------------------------------------------===// |
| ELFObjectWriter::ELFObjectWriter(GNULDBackend& pBackend, |
| const LinkerConfig& pConfig) |
| : ObjectWriter(), m_Backend(pBackend), m_Config(pConfig) { |
| } |
| |
| ELFObjectWriter::~ELFObjectWriter() { |
| } |
| |
| void ELFObjectWriter::writeSection(Module& pModule, |
| FileOutputBuffer& pOutput, |
| LDSection* section) { |
| MemoryRegion region; |
| // Request output region |
| switch (section->kind()) { |
| case LDFileFormat::Note: |
| if (section->getSectionData() == NULL) |
| return; |
| // Fall through |
| case LDFileFormat::TEXT: |
| case LDFileFormat::DATA: |
| case LDFileFormat::Relocation: |
| case LDFileFormat::Target: |
| case LDFileFormat::Debug: |
| case LDFileFormat::DebugString: |
| case LDFileFormat::GCCExceptTable: |
| case LDFileFormat::EhFrame: { |
| region = pOutput.request(section->offset(), section->size()); |
| if (region.size() == 0) { |
| return; |
| } |
| break; |
| } |
| case LDFileFormat::Null: |
| case LDFileFormat::NamePool: |
| case LDFileFormat::BSS: |
| case LDFileFormat::MetaData: |
| case LDFileFormat::Version: |
| case LDFileFormat::EhFrameHdr: |
| case LDFileFormat::StackNote: |
| // Ignore these sections |
| return; |
| default: |
| llvm::errs() << "WARNING: unsupported section kind: " << section->kind() |
| << " of section " << section->name() << ".\n"; |
| return; |
| } |
| |
| // Write out sections with data |
| switch (section->kind()) { |
| case LDFileFormat::GCCExceptTable: |
| case LDFileFormat::TEXT: |
| case LDFileFormat::DATA: |
| case LDFileFormat::Debug: |
| case LDFileFormat::Note: |
| emitSectionData(*section, region); |
| break; |
| case LDFileFormat::EhFrame: |
| emitEhFrame(pModule, *section->getEhFrame(), region); |
| break; |
| case LDFileFormat::Relocation: |
| // sort relocation for the benefit of the dynamic linker. |
| target().sortRelocation(*section); |
| |
| emitRelocation(m_Config, *section, region); |
| break; |
| case LDFileFormat::Target: |
| target().emitSectionData(*section, region); |
| break; |
| case LDFileFormat::DebugString: |
| section->getDebugString()->emit(region); |
| break; |
| default: |
| llvm_unreachable("invalid section kind"); |
| } |
| } |
| |
| std::error_code ELFObjectWriter::writeObject(Module& pModule, |
| FileOutputBuffer& pOutput) { |
| bool is_dynobj = m_Config.codeGenType() == LinkerConfig::DynObj; |
| bool is_exec = m_Config.codeGenType() == LinkerConfig::Exec; |
| bool is_binary = m_Config.codeGenType() == LinkerConfig::Binary; |
| bool is_object = m_Config.codeGenType() == LinkerConfig::Object; |
| |
| assert(is_dynobj || is_exec || is_binary || is_object); |
| |
| if (is_dynobj || is_exec) { |
| // Allow backend to sort symbols before emitting |
| target().orderSymbolTable(pModule); |
| |
| // Write out the interpreter section: .interp |
| target().emitInterp(pOutput); |
| |
| // Write out name pool sections: .dynsym, .dynstr, .hash |
| target().emitDynNamePools(pModule, pOutput); |
| } |
| |
| if (is_object || is_dynobj || is_exec) { |
| // Write out name pool sections: .symtab, .strtab |
| target().emitRegNamePools(pModule, pOutput); |
| } |
| |
| if (is_binary) { |
| // Iterate over the loadable segments and write the corresponding sections |
| ELFSegmentFactory::iterator seg, segEnd = target().elfSegmentTable().end(); |
| |
| for (seg = target().elfSegmentTable().begin(); seg != segEnd; ++seg) { |
| if (llvm::ELF::PT_LOAD == (*seg)->type()) { |
| ELFSegment::iterator sect, sectEnd = (*seg)->end(); |
| for (sect = (*seg)->begin(); sect != sectEnd; ++sect) |
| writeSection(pModule, pOutput, *sect); |
| } |
| } |
| } else { |
| // Write out regular ELF sections |
| Module::iterator sect, sectEnd = pModule.end(); |
| for (sect = pModule.begin(); sect != sectEnd; ++sect) |
| writeSection(pModule, pOutput, *sect); |
| |
| emitShStrTab(target().getOutputFormat()->getShStrTab(), pModule, pOutput); |
| |
| if (m_Config.targets().is32Bits()) { |
| // Write out ELF header |
| // Write out section header table |
| writeELFHeader<32>(m_Config, pModule, pOutput); |
| if (is_dynobj || is_exec) |
| emitProgramHeader<32>(pOutput); |
| |
| emitSectionHeader<32>(pModule, m_Config, pOutput); |
| } else if (m_Config.targets().is64Bits()) { |
| // Write out ELF header |
| // Write out section header table |
| writeELFHeader<64>(m_Config, pModule, pOutput); |
| if (is_dynobj || is_exec) |
| emitProgramHeader<64>(pOutput); |
| |
| emitSectionHeader<64>(pModule, m_Config, pOutput); |
| } else { |
| return llvm::make_error_code(llvm::errc::function_not_supported); |
| } |
| } |
| |
| return std::error_code(); |
| } |
| |
| // getOutputSize - count the final output size |
| size_t ELFObjectWriter::getOutputSize(const Module& pModule) const { |
| if (m_Config.targets().is32Bits()) { |
| return getLastStartOffset<32>(pModule) + |
| sizeof(ELFSizeTraits<32>::Shdr) * pModule.size(); |
| } else if (m_Config.targets().is64Bits()) { |
| return getLastStartOffset<64>(pModule) + |
| sizeof(ELFSizeTraits<64>::Shdr) * pModule.size(); |
| } else { |
| assert(0 && "Invalid ELF Class"); |
| return 0; |
| } |
| } |
| |
| // writeELFHeader - emit ElfXX_Ehdr |
| template <size_t SIZE> |
| void ELFObjectWriter::writeELFHeader(const LinkerConfig& pConfig, |
| const Module& pModule, |
| FileOutputBuffer& pOutput) const { |
| typedef typename ELFSizeTraits<SIZE>::Ehdr ElfXX_Ehdr; |
| typedef typename ELFSizeTraits<SIZE>::Shdr ElfXX_Shdr; |
| typedef typename ELFSizeTraits<SIZE>::Phdr ElfXX_Phdr; |
| |
| // ELF header must start from 0x0 |
| MemoryRegion region = pOutput.request(0, sizeof(ElfXX_Ehdr)); |
| ElfXX_Ehdr* header = reinterpret_cast<ElfXX_Ehdr*>(region.begin()); |
| |
| memcpy(header->e_ident, llvm::ELF::ElfMagic, llvm::ELF::EI_MAG3 + 1); |
| |
| header->e_ident[llvm::ELF::EI_CLASS] = |
| (SIZE == 32) ? llvm::ELF::ELFCLASS32 : llvm::ELF::ELFCLASS64; |
| header->e_ident[llvm::ELF::EI_DATA] = |
| pConfig.targets().isLittleEndian() |
| ? llvm::ELF::ELFDATA2LSB : llvm::ELF::ELFDATA2MSB; |
| header->e_ident[llvm::ELF::EI_VERSION] = target().getInfo().ELFVersion(); |
| header->e_ident[llvm::ELF::EI_OSABI] = target().getInfo().OSABI(); |
| header->e_ident[llvm::ELF::EI_ABIVERSION] = target().getInfo().ABIVersion(); |
| |
| // FIXME: add processor-specific and core file types. |
| switch (pConfig.codeGenType()) { |
| case LinkerConfig::Object: |
| header->e_type = llvm::ELF::ET_REL; |
| break; |
| case LinkerConfig::DynObj: |
| header->e_type = llvm::ELF::ET_DYN; |
| break; |
| case LinkerConfig::Exec: |
| header->e_type = llvm::ELF::ET_EXEC; |
| break; |
| default: |
| llvm::errs() << "unspported output file type: " << pConfig.codeGenType() |
| << ".\n"; |
| header->e_type = llvm::ELF::ET_NONE; |
| } |
| header->e_machine = target().getInfo().machine(); |
| header->e_version = header->e_ident[llvm::ELF::EI_VERSION]; |
| header->e_entry = getEntryPoint(pConfig, pModule); |
| |
| if (LinkerConfig::Object != pConfig.codeGenType()) |
| header->e_phoff = sizeof(ElfXX_Ehdr); |
| else |
| header->e_phoff = 0x0; |
| |
| header->e_shoff = getLastStartOffset<SIZE>(pModule); |
| header->e_flags = target().getInfo().flags(); |
| header->e_ehsize = sizeof(ElfXX_Ehdr); |
| header->e_phentsize = sizeof(ElfXX_Phdr); |
| header->e_phnum = target().elfSegmentTable().size(); |
| header->e_shentsize = sizeof(ElfXX_Shdr); |
| header->e_shnum = pModule.size(); |
| header->e_shstrndx = pModule.getSection(".shstrtab")->index(); |
| } |
| |
| /// getEntryPoint |
| uint64_t ELFObjectWriter::getEntryPoint(const LinkerConfig& pConfig, |
| const Module& pModule) const { |
| llvm::StringRef entry_name = target().getEntry(pModule); |
| uint64_t result = 0x0; |
| |
| bool issue_warning = (pModule.getScript().hasEntry() && |
| LinkerConfig::Object != pConfig.codeGenType() && |
| LinkerConfig::DynObj != pConfig.codeGenType()); |
| |
| const LDSymbol* entry_symbol = pModule.getNamePool().findSymbol(entry_name); |
| |
| // found the symbol |
| if (entry_symbol != NULL) { |
| if (entry_symbol->desc() != ResolveInfo::Define && issue_warning) { |
| llvm::errs() << "WARNING: entry symbol '" << entry_symbol->name() |
| << "' exists but is not defined.\n"; |
| } |
| result = entry_symbol->value(); |
| } else { |
| // not in the symbol pool |
| // We should parse entry as a number. |
| // @ref GNU ld manual, Options -e. e.g., -e 0x1000. |
| char* endptr; |
| result = strtoull(entry_name.data(), &endptr, 0); |
| if (*endptr != '\0') { |
| if (issue_warning) { |
| llvm::errs() << "cannot find entry symbol '" << entry_name.data() |
| << "'.\n"; |
| } |
| result = 0x0; |
| } |
| } |
| return result; |
| } |
| |
| // emitSectionHeader - emit ElfXX_Shdr |
| template <size_t SIZE> |
| void ELFObjectWriter::emitSectionHeader(const Module& pModule, |
| const LinkerConfig& pConfig, |
| FileOutputBuffer& pOutput) const { |
| typedef typename ELFSizeTraits<SIZE>::Shdr ElfXX_Shdr; |
| |
| // emit section header |
| unsigned int sectNum = pModule.size(); |
| unsigned int header_size = sizeof(ElfXX_Shdr) * sectNum; |
| MemoryRegion region = |
| pOutput.request(getLastStartOffset<SIZE>(pModule), header_size); |
| ElfXX_Shdr* shdr = reinterpret_cast<ElfXX_Shdr*>(region.begin()); |
| |
| // Iterate the SectionTable in LDContext |
| unsigned int sectIdx = 0; |
| unsigned int shstridx = 0; // NULL section has empty name |
| for (; sectIdx < sectNum; ++sectIdx) { |
| const LDSection* ld_sect = pModule.getSectionTable().at(sectIdx); |
| shdr[sectIdx].sh_name = shstridx; |
| shdr[sectIdx].sh_type = ld_sect->type(); |
| shdr[sectIdx].sh_flags = ld_sect->flag(); |
| shdr[sectIdx].sh_addr = ld_sect->addr(); |
| shdr[sectIdx].sh_offset = ld_sect->offset(); |
| shdr[sectIdx].sh_size = ld_sect->size(); |
| shdr[sectIdx].sh_addralign = ld_sect->align(); |
| shdr[sectIdx].sh_entsize = getSectEntrySize<SIZE>(*ld_sect); |
| shdr[sectIdx].sh_link = getSectLink(*ld_sect, pConfig); |
| shdr[sectIdx].sh_info = getSectInfo(*ld_sect); |
| |
| // adjust strshidx |
| shstridx += ld_sect->name().size() + 1; |
| } |
| } |
| |
| // emitProgramHeader - emit ElfXX_Phdr |
| template <size_t SIZE> |
| void ELFObjectWriter::emitProgramHeader(FileOutputBuffer& pOutput) const { |
| typedef typename ELFSizeTraits<SIZE>::Ehdr ElfXX_Ehdr; |
| typedef typename ELFSizeTraits<SIZE>::Phdr ElfXX_Phdr; |
| |
| uint64_t start_offset, phdr_size; |
| |
| start_offset = sizeof(ElfXX_Ehdr); |
| phdr_size = sizeof(ElfXX_Phdr); |
| // Program header must start directly after ELF header |
| MemoryRegion region = pOutput.request( |
| start_offset, target().elfSegmentTable().size() * phdr_size); |
| |
| ElfXX_Phdr* phdr = reinterpret_cast<ElfXX_Phdr*>(region.begin()); |
| |
| // Iterate the elf segment table in GNULDBackend |
| size_t index = 0; |
| ELFSegmentFactory::const_iterator seg = target().elfSegmentTable().begin(), |
| segEnd = target().elfSegmentTable().end(); |
| for (; seg != segEnd; ++seg, ++index) { |
| phdr[index].p_type = (*seg)->type(); |
| phdr[index].p_flags = (*seg)->flag(); |
| phdr[index].p_offset = (*seg)->offset(); |
| phdr[index].p_vaddr = (*seg)->vaddr(); |
| phdr[index].p_paddr = (*seg)->paddr(); |
| phdr[index].p_filesz = (*seg)->filesz(); |
| phdr[index].p_memsz = (*seg)->memsz(); |
| phdr[index].p_align = (*seg)->align(); |
| } |
| } |
| |
| /// emitShStrTab - emit section string table |
| void ELFObjectWriter::emitShStrTab(const LDSection& pShStrTab, |
| const Module& pModule, |
| FileOutputBuffer& pOutput) { |
| // write out data |
| MemoryRegion region = pOutput.request(pShStrTab.offset(), pShStrTab.size()); |
| char* data = reinterpret_cast<char*>(region.begin()); |
| size_t shstrsize = 0; |
| Module::const_iterator section, sectEnd = pModule.end(); |
| for (section = pModule.begin(); section != sectEnd; ++section) { |
| ::memcpy(reinterpret_cast<char*>(data + shstrsize), |
| (*section)->name().data(), |
| (*section)->name().size()); |
| shstrsize += (*section)->name().size() + 1; |
| } |
| } |
| |
| /// emitSectionData |
| void ELFObjectWriter::emitSectionData(const LDSection& pSection, |
| MemoryRegion& pRegion) const { |
| const SectionData* sd = NULL; |
| switch (pSection.kind()) { |
| case LDFileFormat::Relocation: |
| assert(pSection.hasRelocData()); |
| return; |
| case LDFileFormat::EhFrame: |
| assert(pSection.hasEhFrame()); |
| sd = pSection.getEhFrame()->getSectionData(); |
| break; |
| default: |
| assert(pSection.hasSectionData()); |
| sd = pSection.getSectionData(); |
| break; |
| } |
| emitSectionData(*sd, pRegion); |
| } |
| |
| /// emitEhFrame |
| void ELFObjectWriter::emitEhFrame(Module& pModule, |
| EhFrame& pFrame, |
| MemoryRegion& pRegion) const { |
| emitSectionData(*pFrame.getSectionData(), pRegion); |
| |
| // Patch FDE field (offset to CIE) |
| for (EhFrame::cie_iterator i = pFrame.cie_begin(), e = pFrame.cie_end(); |
| i != e; |
| ++i) { |
| EhFrame::CIE& cie = **i; |
| for (EhFrame::fde_iterator fi = cie.begin(), fe = cie.end(); fi != fe; |
| ++fi) { |
| EhFrame::FDE& fde = **fi; |
| if (fde.getRecordType() == EhFrame::RECORD_GENERATED) { |
| // Patch PLT offset |
| LDSection* plt_sect = pModule.getSection(".plt"); |
| assert(plt_sect && "We have no plt but have corresponding eh_frame?"); |
| uint64_t plt_offset = plt_sect->offset(); |
| // FDE entry for PLT is always 32-bit |
| uint64_t fde_offset = pFrame.getSection().offset() + fde.getOffset() + |
| EhFrame::getDataStartOffset<32>(); |
| int32_t offset = fde_offset - plt_offset; |
| if (plt_offset < fde_offset) |
| offset = -offset; |
| memcpy(pRegion.begin() + fde.getOffset() + |
| EhFrame::getDataStartOffset<32>(), |
| &offset, |
| 4); |
| uint32_t size = plt_sect->size(); |
| memcpy(pRegion.begin() + fde.getOffset() + |
| EhFrame::getDataStartOffset<32>() + 4, |
| &size, |
| 4); |
| } |
| uint64_t fde_cie_ptr_offset = fde.getOffset() + |
| EhFrame::getDataStartOffset<32>() - |
| /*ID*/ 4; |
| uint64_t cie_start_offset = cie.getOffset(); |
| int32_t offset = fde_cie_ptr_offset - cie_start_offset; |
| if (fde_cie_ptr_offset < cie_start_offset) |
| offset = -offset; |
| memcpy(pRegion.begin() + fde_cie_ptr_offset, &offset, 4); |
| } // for loop fde_iterator |
| } // for loop cie_iterator |
| } |
| |
| /// emitRelocation |
| void ELFObjectWriter::emitRelocation(const LinkerConfig& pConfig, |
| const LDSection& pSection, |
| MemoryRegion& pRegion) const { |
| const RelocData* sect_data = pSection.getRelocData(); |
| assert(sect_data != NULL && "SectionData is NULL in emitRelocation!"); |
| |
| if (pSection.type() == llvm::ELF::SHT_REL) { |
| if (pConfig.targets().is32Bits()) |
| emitRel<32>(pConfig, *sect_data, pRegion); |
| else if (pConfig.targets().is64Bits()) |
| emitRel<64>(pConfig, *sect_data, pRegion); |
| else { |
| fatal(diag::unsupported_bitclass) << pConfig.targets().triple().str() |
| << pConfig.targets().bitclass(); |
| } |
| } else if (pSection.type() == llvm::ELF::SHT_RELA) { |
| if (pConfig.targets().is32Bits()) |
| emitRela<32>(pConfig, *sect_data, pRegion); |
| else if (pConfig.targets().is64Bits()) |
| emitRela<64>(pConfig, *sect_data, pRegion); |
| else { |
| fatal(diag::unsupported_bitclass) << pConfig.targets().triple().str() |
| << pConfig.targets().bitclass(); |
| } |
| } else |
| llvm::report_fatal_error("unsupported relocation section type!"); |
| } |
| |
| // emitRel - emit ElfXX_Rel |
| template <size_t SIZE> |
| void ELFObjectWriter::emitRel(const LinkerConfig& pConfig, |
| const RelocData& pRelocData, |
| MemoryRegion& pRegion) const { |
| typedef typename ELFSizeTraits<SIZE>::Rel ElfXX_Rel; |
| typedef typename ELFSizeTraits<SIZE>::Addr ElfXX_Addr; |
| typedef typename ELFSizeTraits<SIZE>::Word ElfXX_Word; |
| |
| ElfXX_Rel* rel = reinterpret_cast<ElfXX_Rel*>(pRegion.begin()); |
| |
| const Relocation* relocation = 0; |
| const FragmentRef* frag_ref = 0; |
| |
| for (RelocData::const_iterator it = pRelocData.begin(), ie = pRelocData.end(); |
| it != ie; |
| ++it, ++rel) { |
| ElfXX_Addr r_offset = 0; |
| ElfXX_Word r_sym = 0; |
| |
| relocation = &(llvm::cast<Relocation>(*it)); |
| frag_ref = &(relocation->targetRef()); |
| |
| if (LinkerConfig::DynObj == pConfig.codeGenType() || |
| LinkerConfig::Exec == pConfig.codeGenType()) { |
| r_offset = static_cast<ElfXX_Addr>( |
| frag_ref->frag()->getParent()->getSection().addr() + |
| frag_ref->getOutputOffset()); |
| } else { |
| r_offset = static_cast<ElfXX_Addr>(frag_ref->getOutputOffset()); |
| } |
| |
| if (relocation->symInfo() == NULL) |
| r_sym = 0; |
| else |
| r_sym = static_cast<ElfXX_Word>( |
| target().getSymbolIdx(relocation->symInfo()->outSymbol())); |
| |
| target().emitRelocation(*rel, relocation->type(), r_sym, r_offset); |
| } |
| } |
| |
| // emitRela - emit ElfXX_Rela |
| template <size_t SIZE> |
| void ELFObjectWriter::emitRela(const LinkerConfig& pConfig, |
| const RelocData& pRelocData, |
| MemoryRegion& pRegion) const { |
| typedef typename ELFSizeTraits<SIZE>::Rela ElfXX_Rela; |
| typedef typename ELFSizeTraits<SIZE>::Addr ElfXX_Addr; |
| typedef typename ELFSizeTraits<SIZE>::Word ElfXX_Word; |
| |
| ElfXX_Rela* rel = reinterpret_cast<ElfXX_Rela*>(pRegion.begin()); |
| |
| const Relocation* relocation = 0; |
| const FragmentRef* frag_ref = 0; |
| |
| for (RelocData::const_iterator it = pRelocData.begin(), ie = pRelocData.end(); |
| it != ie; |
| ++it, ++rel) { |
| ElfXX_Addr r_offset = 0; |
| ElfXX_Word r_sym = 0; |
| |
| relocation = &(llvm::cast<Relocation>(*it)); |
| frag_ref = &(relocation->targetRef()); |
| |
| if (LinkerConfig::DynObj == pConfig.codeGenType() || |
| LinkerConfig::Exec == pConfig.codeGenType()) { |
| r_offset = static_cast<ElfXX_Addr>( |
| frag_ref->frag()->getParent()->getSection().addr() + |
| frag_ref->getOutputOffset()); |
| } else { |
| r_offset = static_cast<ElfXX_Addr>(frag_ref->getOutputOffset()); |
| } |
| |
| if (relocation->symInfo() == NULL) |
| r_sym = 0; |
| else |
| r_sym = static_cast<ElfXX_Word>( |
| target().getSymbolIdx(relocation->symInfo()->outSymbol())); |
| |
| target().emitRelocation( |
| *rel, relocation->type(), r_sym, r_offset, relocation->addend()); |
| } |
| } |
| |
| /// getSectEntrySize - compute ElfXX_Shdr::sh_entsize |
| template <size_t SIZE> |
| uint64_t ELFObjectWriter::getSectEntrySize(const LDSection& pSection) const { |
| typedef typename ELFSizeTraits<SIZE>::Word ElfXX_Word; |
| typedef typename ELFSizeTraits<SIZE>::Sym ElfXX_Sym; |
| typedef typename ELFSizeTraits<SIZE>::Rel ElfXX_Rel; |
| typedef typename ELFSizeTraits<SIZE>::Rela ElfXX_Rela; |
| typedef typename ELFSizeTraits<SIZE>::Dyn ElfXX_Dyn; |
| |
| if (llvm::ELF::SHT_DYNSYM == pSection.type() || |
| llvm::ELF::SHT_SYMTAB == pSection.type()) |
| return sizeof(ElfXX_Sym); |
| if (llvm::ELF::SHT_REL == pSection.type()) |
| return sizeof(ElfXX_Rel); |
| if (llvm::ELF::SHT_RELA == pSection.type()) |
| return sizeof(ElfXX_Rela); |
| if (llvm::ELF::SHT_HASH == pSection.type() || |
| llvm::ELF::SHT_GNU_HASH == pSection.type()) |
| return sizeof(ElfXX_Word); |
| if (llvm::ELF::SHT_DYNAMIC == pSection.type()) |
| return sizeof(ElfXX_Dyn); |
| // FIXME: We should get the entsize from input since the size of each |
| // character is specified in the section header's sh_entsize field. |
| // For example, traditional string is 0x1, UCS-2 is 0x2, ... and so on. |
| // Ref: http://www.sco.com/developers/gabi/2003-12-17/ch4.sheader.html |
| if (pSection.flag() & llvm::ELF::SHF_STRINGS) |
| return 0x1; |
| return 0x0; |
| } |
| |
| /// getSectLink - compute ElfXX_Shdr::sh_link |
| uint64_t ELFObjectWriter::getSectLink(const LDSection& pSection, |
| const LinkerConfig& pConfig) const { |
| if (llvm::ELF::SHT_SYMTAB == pSection.type()) |
| return target().getOutputFormat()->getStrTab().index(); |
| if (llvm::ELF::SHT_DYNSYM == pSection.type()) |
| return target().getOutputFormat()->getDynStrTab().index(); |
| if (llvm::ELF::SHT_DYNAMIC == pSection.type()) |
| return target().getOutputFormat()->getDynStrTab().index(); |
| if (llvm::ELF::SHT_HASH == pSection.type() || |
| llvm::ELF::SHT_GNU_HASH == pSection.type()) |
| return target().getOutputFormat()->getDynSymTab().index(); |
| if (llvm::ELF::SHT_REL == pSection.type() || |
| llvm::ELF::SHT_RELA == pSection.type()) { |
| if (LinkerConfig::Object == pConfig.codeGenType()) |
| return target().getOutputFormat()->getSymTab().index(); |
| else |
| return target().getOutputFormat()->getDynSymTab().index(); |
| } |
| // FIXME: currently we link ARM_EXIDX section to output text section here |
| if (llvm::ELF::SHT_ARM_EXIDX == pSection.type()) |
| return target().getOutputFormat()->getText().index(); |
| return llvm::ELF::SHN_UNDEF; |
| } |
| |
| /// getSectInfo - compute ElfXX_Shdr::sh_info |
| uint64_t ELFObjectWriter::getSectInfo(const LDSection& pSection) const { |
| if (llvm::ELF::SHT_SYMTAB == pSection.type() || |
| llvm::ELF::SHT_DYNSYM == pSection.type()) |
| return pSection.getInfo(); |
| |
| if (llvm::ELF::SHT_REL == pSection.type() || |
| llvm::ELF::SHT_RELA == pSection.type()) { |
| const LDSection* info_link = pSection.getLink(); |
| if (info_link != NULL) |
| return info_link->index(); |
| } |
| |
| return 0x0; |
| } |
| |
| /// getLastStartOffset |
| template <> |
| uint64_t ELFObjectWriter::getLastStartOffset<32>(const Module& pModule) const { |
| const LDSection* lastSect = pModule.back(); |
| assert(lastSect != NULL); |
| return Align<32>(lastSect->offset() + lastSect->size()); |
| } |
| |
| /// getLastStartOffset |
| template <> |
| uint64_t ELFObjectWriter::getLastStartOffset<64>(const Module& pModule) const { |
| const LDSection* lastSect = pModule.back(); |
| assert(lastSect != NULL); |
| return Align<64>(lastSect->offset() + lastSect->size()); |
| } |
| |
| /// emitSectionData |
| void ELFObjectWriter::emitSectionData(const SectionData& pSD, |
| MemoryRegion& pRegion) const { |
| SectionData::const_iterator fragIter, fragEnd = pSD.end(); |
| size_t cur_offset = 0; |
| for (fragIter = pSD.begin(); fragIter != fragEnd; ++fragIter) { |
| size_t size = fragIter->size(); |
| switch (fragIter->getKind()) { |
| case Fragment::Region: { |
| const RegionFragment& region_frag = |
| llvm::cast<RegionFragment>(*fragIter); |
| const char* from = region_frag.getRegion().begin(); |
| memcpy(pRegion.begin() + cur_offset, from, size); |
| break; |
| } |
| case Fragment::Alignment: { |
| // TODO: emit values with different sizes (> 1 byte), and emit nops |
| const AlignFragment& align_frag = llvm::cast<AlignFragment>(*fragIter); |
| uint64_t count = size / align_frag.getValueSize(); |
| switch (align_frag.getValueSize()) { |
| case 1u: |
| std::memset( |
| pRegion.begin() + cur_offset, align_frag.getValue(), count); |
| break; |
| default: |
| llvm::report_fatal_error( |
| "unsupported value size for align fragment emission yet.\n"); |
| break; |
| } |
| break; |
| } |
| case Fragment::Fillment: { |
| const FillFragment& fill_frag = llvm::cast<FillFragment>(*fragIter); |
| if (0 == size || 0 == fill_frag.getValueSize() || |
| 0 == fill_frag.size()) { |
| // ignore virtual fillment |
| break; |
| } |
| |
| uint64_t num_tiles = fill_frag.size() / fill_frag.getValueSize(); |
| for (uint64_t i = 0; i != num_tiles; ++i) { |
| std::memset(pRegion.begin() + cur_offset, |
| fill_frag.getValue(), |
| fill_frag.getValueSize()); |
| } |
| break; |
| } |
| case Fragment::Stub: { |
| const Stub& stub_frag = llvm::cast<Stub>(*fragIter); |
| memcpy(pRegion.begin() + cur_offset, stub_frag.getContent(), size); |
| break; |
| } |
| case Fragment::Null: { |
| assert(0x0 == size); |
| break; |
| } |
| case Fragment::Target: |
| llvm::report_fatal_error( |
| "Target fragment should not be in a regular section.\n"); |
| break; |
| default: |
| llvm::report_fatal_error( |
| "invalid fragment should not be in a regular section.\n"); |
| break; |
| } |
| cur_offset += size; |
| } |
| } |
| |
| } // namespace mcld |
