| //===- ARMLDBackend.cpp ---------------------------------------------------===// |
| // |
| // The MCLinker Project |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| #include "ARM.h" |
| #include "ARMELFDynamic.h" |
| #include "ARMLDBackend.h" |
| #include "ARMRelocationFactory.h" |
| |
| #include <cstring> |
| |
| #include <llvm/ADT/Triple.h> |
| #include <llvm/ADT/Twine.h> |
| #include <llvm/Support/ELF.h> |
| #include <llvm/Support/Casting.h> |
| |
| #include <mcld/LD/SectionMap.h> |
| #include <mcld/LD/FillFragment.h> |
| #include <mcld/LD/AlignFragment.h> |
| #include <mcld/LD/RegionFragment.h> |
| #include <mcld/MC/MCLDInfo.h> |
| #include <mcld/MC/MCLDOutput.h> |
| #include <mcld/MC/MCLinker.h> |
| #include <mcld/Support/MemoryRegion.h> |
| #include <mcld/Support/MsgHandling.h> |
| #include <mcld/Support/TargetRegistry.h> |
| |
| using namespace mcld; |
| |
| //===----------------------------------------------------------------------===// |
| // ARMGNULDBackend |
| //===----------------------------------------------------------------------===// |
| ARMGNULDBackend::ARMGNULDBackend() |
| : m_pRelocFactory(NULL), |
| m_pGOT(NULL), |
| m_pPLT(NULL), |
| m_pRelDyn(NULL), |
| m_pRelPLT(NULL), |
| m_pDynamic(NULL), |
| m_pGOTSymbol(NULL), |
| m_pEXIDX(NULL), |
| m_pEXTAB(NULL), |
| m_pAttributes(NULL) { |
| } |
| |
| ARMGNULDBackend::~ARMGNULDBackend() |
| { |
| if (NULL != m_pRelocFactory) |
| delete m_pRelocFactory; |
| if (NULL != m_pGOT) |
| delete m_pGOT; |
| if (NULL != m_pPLT) |
| delete m_pPLT; |
| if (NULL != m_pRelDyn) |
| delete m_pRelDyn; |
| if (NULL != m_pRelPLT) |
| delete m_pRelPLT; |
| if (NULL != m_pDynamic) |
| delete m_pDynamic; |
| } |
| |
| bool ARMGNULDBackend::initRelocFactory(const MCLinker& pLinker) |
| { |
| if (NULL == m_pRelocFactory) { |
| m_pRelocFactory = new ARMRelocationFactory(1024, *this); |
| m_pRelocFactory->setLayout(pLinker.getLayout()); |
| } |
| return true; |
| } |
| |
| RelocationFactory* ARMGNULDBackend::getRelocFactory() |
| { |
| assert(NULL != m_pRelocFactory); |
| return m_pRelocFactory; |
| } |
| |
| bool ARMGNULDBackend::initTargetSectionMap(SectionMap& pSectionMap) |
| { |
| if (!pSectionMap.push_back(".ARM.exidx", ".ARM.exidx") || |
| !pSectionMap.push_back(".ARM.extab", ".ARM.extab") || |
| !pSectionMap.push_back(".ARM.attributes", ".ARM.attributes")) |
| return false; |
| return true; |
| } |
| |
| void ARMGNULDBackend::initTargetSections(MCLinker& pLinker) |
| { |
| // FIXME: Currently we set exidx and extab to "Exception" and directly emit |
| // them from input |
| m_pEXIDX = &pLinker.getOrCreateOutputSectHdr(".ARM.exidx", |
| LDFileFormat::Target, |
| llvm::ELF::SHT_ARM_EXIDX, |
| llvm::ELF::SHF_ALLOC | llvm::ELF::SHF_LINK_ORDER, |
| bitclass() / 8); |
| m_pEXTAB = &pLinker.getOrCreateOutputSectHdr(".ARM.extab", |
| LDFileFormat::Target, |
| llvm::ELF::SHT_PROGBITS, |
| llvm::ELF::SHF_ALLOC, |
| 0x1); |
| m_pAttributes = &pLinker.getOrCreateOutputSectHdr(".ARM.attributes", |
| LDFileFormat::Target, |
| llvm::ELF::SHT_ARM_ATTRIBUTES, |
| 0x0, |
| 0x1); |
| } |
| |
| void ARMGNULDBackend::initTargetSymbols(MCLinker& pLinker, const Output& pOutput) |
| { |
| // Define the symbol _GLOBAL_OFFSET_TABLE_ if there is a symbol with the |
| // same name in input |
| m_pGOTSymbol = pLinker.defineSymbol<MCLinker::AsRefered, MCLinker::Resolve>( |
| "_GLOBAL_OFFSET_TABLE_", |
| false, |
| ResolveInfo::Object, |
| ResolveInfo::Define, |
| ResolveInfo::Local, |
| 0x0, // size |
| 0x0, // value |
| NULL, // FragRef |
| ResolveInfo::Hidden); |
| } |
| |
| void ARMGNULDBackend::doPreLayout(const Output& pOutput, |
| const MCLDInfo& pInfo, |
| MCLinker& pLinker) |
| { |
| // when building shared object, the .got section is must. |
| if (pOutput.type() == Output::DynObj && (NULL == m_pGOT)) { |
| createARMGOT(pLinker, pOutput); |
| } |
| } |
| |
| void ARMGNULDBackend::doPostLayout(const Output& pOutput, |
| const MCLDInfo& pInfo, |
| MCLinker& pLinker) |
| { |
| const ELFFileFormat *file_format = getOutputFormat(pOutput); |
| |
| // apply PLT |
| if (file_format->hasPLT()) { |
| // Since we already have the size of LDSection PLT, m_pPLT should not be |
| // NULL. |
| assert(NULL != m_pPLT); |
| m_pPLT->applyPLT0(); |
| m_pPLT->applyPLT1(); |
| } |
| |
| // apply GOT |
| if (file_format->hasGOT()) { |
| // Since we already have the size of GOT, m_pGOT should not be NULL. |
| assert(NULL != m_pGOT); |
| if (pOutput.type() == Output::DynObj) |
| m_pGOT->applyGOT0(file_format->getDynamic().addr()); |
| else { |
| // executable file and object file? should fill with zero. |
| m_pGOT->applyGOT0(0); |
| } |
| } |
| } |
| |
| /// dynamic - the dynamic section of the target machine. |
| /// Use co-variant return type to return its own dynamic section. |
| ARMELFDynamic& ARMGNULDBackend::dynamic() |
| { |
| if (NULL == m_pDynamic) |
| m_pDynamic = new ARMELFDynamic(*this); |
| |
| return *m_pDynamic; |
| } |
| |
| /// dynamic - the dynamic section of the target machine. |
| /// Use co-variant return type to return its own dynamic section. |
| const ARMELFDynamic& ARMGNULDBackend::dynamic() const |
| { |
| assert( NULL != m_pDynamic); |
| return *m_pDynamic; |
| } |
| |
| void ARMGNULDBackend::createARMGOT(MCLinker& pLinker, const Output& pOutput) |
| { |
| // get .got LDSection and create SectionData |
| 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 SectionData and ARMPLT |
| m_pPLT = new ARMPLT(plt, pLinker.getOrCreateSectData(plt), *m_pGOT); |
| // set info of .rel.plt to .plt |
| relplt.setLink(&plt); |
| // create SectionData 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 SectionData |
| LDSection& reldyn = file_format->getRelDyn(); |
| // create SectionData and ARMRelDynSection |
| m_pRelDyn = new OutputRelocSection(reldyn, |
| pLinker.getOrCreateSectData(reldyn), |
| 8); |
| } |
| |
| void ARMGNULDBackend::addCopyReloc(ResolveInfo& pSym) |
| { |
| bool exist; |
| Relocation& rel_entry = *m_pRelDyn->getEntry(pSym, false, exist); |
| rel_entry.setType(llvm::ELF::R_ARM_COPY); |
| assert(pSym.outSymbol()->hasFragRef()); |
| rel_entry.targetRef().assign(*pSym.outSymbol()->fragRef()); |
| rel_entry.setSymInfo(&pSym); |
| } |
| |
| LDSymbol& ARMGNULDBackend::defineSymbolforCopyReloc(MCLinker& pLinker, |
| const ResolveInfo& pSym) |
| { |
| // For a symbol needing copy relocation, define a copy symbol in the BSS |
| // section and all other reference to this symbol should refer to this |
| // copy. |
| |
| // get or create corresponding BSS LDSection |
| LDSection* bss_sect_hdr = NULL; |
| if (ResolveInfo::ThreadLocal == pSym.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 SectionData |
| assert(NULL != bss_sect_hdr); |
| SectionData& bss_section = pLinker.getOrCreateSectData( |
| *bss_sect_hdr); |
| |
| // Determine the alignment by the symbol value |
| // FIXME: here we use the largest alignment |
| uint32_t addralign = bitclass() / 8; |
| |
| // allocate space in BSS for the copy symbol |
| Fragment* frag = new FillFragment(0x0, 1, pSym.size()); |
| uint64_t size = pLinker.getLayout().appendFragment(*frag, |
| bss_section, |
| addralign); |
| bss_sect_hdr->setSize(bss_sect_hdr->size() + size); |
| |
| // change symbol binding to Global if it's a weak symbol |
| ResolveInfo::Binding binding = (ResolveInfo::Binding)pSym.binding(); |
| if (binding == ResolveInfo::Weak) |
| binding = ResolveInfo::Global; |
| |
| // Define the copy symbol in the bss section and resolve it |
| LDSymbol* cpy_sym = pLinker.defineSymbol<MCLinker::Force, MCLinker::Resolve>( |
| pSym.name(), |
| false, |
| (ResolveInfo::Type)pSym.type(), |
| ResolveInfo::Define, |
| binding, |
| pSym.size(), // size |
| 0x0, // value |
| pLinker.getLayout().getFragmentRef(*frag, 0x0), |
| (ResolveInfo::Visibility)pSym.other()); |
| |
| return *cpy_sym; |
| } |
| |
| /// checkValidReloc - When we attempt to generate a dynamic relocation for |
| /// ouput file, check if the relocation is supported by dynamic linker. |
| void ARMGNULDBackend::checkValidReloc(Relocation& pReloc, |
| const MCLDInfo& pLDInfo, |
| const Output& pOutput) const |
| { |
| // If not building a PIC object, no relocation type is invalid |
| if (!isOutputPIC(pOutput, pLDInfo)) |
| return; |
| |
| switch(pReloc.type()) { |
| case llvm::ELF::R_ARM_RELATIVE: |
| case llvm::ELF::R_ARM_COPY: |
| case llvm::ELF::R_ARM_GLOB_DAT: |
| case llvm::ELF::R_ARM_JUMP_SLOT: |
| case llvm::ELF::R_ARM_ABS32: |
| case llvm::ELF::R_ARM_ABS32_NOI: |
| case llvm::ELF::R_ARM_PC24: |
| case llvm::ELF::R_ARM_TLS_DTPMOD32: |
| case llvm::ELF::R_ARM_TLS_DTPOFF32: |
| case llvm::ELF::R_ARM_TLS_TPOFF32: |
| break; |
| |
| default: |
| error(diag::non_pic_relocation) << (int)pReloc.type() |
| << pReloc.symInfo()->name(); |
| break; |
| } |
| } |
| |
| void ARMGNULDBackend::updateAddend(Relocation& pReloc, |
| const LDSymbol& pInputSym, |
| const Layout& pLayout) const |
| { |
| // Update value keep in addend if we meet a section symbol |
| if (pReloc.symInfo()->type() == ResolveInfo::Section) { |
| pReloc.setAddend(pLayout.getOutputOffset( |
| *pInputSym.fragRef()) + pReloc.addend()); |
| } |
| } |
| |
| void ARMGNULDBackend::scanLocalReloc(Relocation& pReloc, |
| const LDSymbol& pInputSym, |
| MCLinker& pLinker, |
| const MCLDInfo& pLDInfo, |
| const Output& pOutput) |
| { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| |
| updateAddend(pReloc, pInputSym, pLinker.getLayout()); |
| |
| switch(pReloc.type()){ |
| |
| // Set R_ARM_TARGET1 to R_ARM_ABS32 |
| // Ref: GNU gold 1.11 arm.cc, line 9892 |
| // FIXME: R_ARM_TARGET1 should be set by option --target1-rel |
| // or --target1-rel |
| case llvm::ELF::R_ARM_TARGET1: |
| pReloc.setType(llvm::ELF::R_ARM_ABS32); |
| case llvm::ELF::R_ARM_ABS32: |
| case llvm::ELF::R_ARM_ABS32_NOI: { |
| // If buiding PIC object (shared library or PIC executable), |
| // a dynamic relocations with RELATIVE type to this location is needed. |
| // Reserve an entry in .rel.dyn |
| if (isOutputPIC(pOutput, pLDInfo)) { |
| //create .rel.dyn section if not exist |
| if (NULL == m_pRelDyn) |
| createARMRelDyn(pLinker, pOutput); |
| m_pRelDyn->reserveEntry(*m_pRelocFactory); |
| // set Rel bit |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| } |
| return; |
| } |
| |
| case llvm::ELF::R_ARM_ABS16: |
| case llvm::ELF::R_ARM_ABS12: |
| case llvm::ELF::R_ARM_THM_ABS5: |
| case llvm::ELF::R_ARM_ABS8: |
| case llvm::ELF::R_ARM_BASE_ABS: |
| case llvm::ELF::R_ARM_MOVW_ABS_NC: |
| case llvm::ELF::R_ARM_MOVT_ABS: |
| case llvm::ELF::R_ARM_THM_MOVW_ABS_NC: |
| case llvm::ELF::R_ARM_THM_MOVT_ABS: { |
| // PIC code should not contain these kinds of relocation |
| if (isOutputPIC(pOutput, pLDInfo)) { |
| error(diag::non_pic_relocation) << (int)pReloc.type() |
| << pReloc.symInfo()->name(); |
| } |
| return; |
| } |
| case llvm::ELF::R_ARM_GOTOFF32: |
| case llvm::ELF::R_ARM_GOTOFF12: { |
| // A GOT section is needed |
| if (NULL == m_pGOT) |
| createARMGOT(pLinker, pOutput); |
| return; |
| } |
| |
| // Set R_ARM_TARGET2 to R_ARM_GOT_PREL |
| // Ref: GNU gold 1.11 arm.cc, line 9892 |
| // FIXME: R_ARM_TARGET2 should be set by option --target2 |
| case llvm::ELF::R_ARM_TARGET2: |
| pReloc.setType(llvm::ELF::R_ARM_GOT_PREL); |
| case llvm::ELF::R_ARM_GOT_BREL: |
| case llvm::ELF::R_ARM_GOT_PREL: { |
| // A GOT entry is needed for these relocation type. |
| // return if we already create GOT for this symbol |
| if (rsym->reserved() & (ReserveGOT | GOTRel)) |
| return; |
| if (NULL == m_pGOT) |
| createARMGOT(pLinker, pOutput); |
| m_pGOT->reserveEntry(); |
| // If building PIC object, a dynamic relocation with |
| // type RELATIVE is needed to relocate this GOT entry. |
| // Reserve an entry in .rel.dyn |
| if (isOutputPIC(pOutput, pLDInfo)) { |
| // create .rel.dyn section if not exist |
| if (NULL == m_pRelDyn) |
| createARMRelDyn(pLinker, pOutput); |
| m_pRelDyn->reserveEntry(*m_pRelocFactory); |
| // set GOTRel bit |
| rsym->setReserved(rsym->reserved() | 0x4u); |
| return; |
| } |
| // set GOT bit |
| rsym->setReserved(rsym->reserved() | 0x2u); |
| return; |
| } |
| |
| case llvm::ELF::R_ARM_BASE_PREL: { |
| // FIXME: Currently we only support R_ARM_BASE_PREL against |
| // symbol _GLOBAL_OFFSET_TABLE_ |
| if (rsym != m_pGOTSymbol->resolveInfo()) |
| fatal(diag::base_relocation) << (int)pReloc.type() << rsym->name() |
| << "mclinker@googlegroups.com"; |
| return; |
| } |
| case llvm::ELF::R_ARM_COPY: |
| case llvm::ELF::R_ARM_GLOB_DAT: |
| case llvm::ELF::R_ARM_JUMP_SLOT: |
| case llvm::ELF::R_ARM_RELATIVE: { |
| // These are relocation type for dynamic linker, shold not |
| // appear in object file. |
| fatal(diag::dynamic_relocation) << (int)pReloc.type(); |
| break; |
| } |
| default: { |
| break; |
| } |
| } // end switch |
| } |
| |
| void ARMGNULDBackend::scanGlobalReloc(Relocation& pReloc, |
| const LDSymbol& pInputSym, |
| MCLinker& pLinker, |
| const MCLDInfo& pLDInfo, |
| const Output& pOutput) |
| { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| |
| switch(pReloc.type()) { |
| |
| // Set R_ARM_TARGET1 to R_ARM_ABS32 |
| // Ref: GNU gold 1.11 arm.cc, line 9892 |
| // FIXME: R_ARM_TARGET1 should be set by option --target1-rel |
| // or --target1-rel |
| case llvm::ELF::R_ARM_TARGET1: |
| pReloc.setType(llvm::ELF::R_ARM_ABS32); |
| case llvm::ELF::R_ARM_ABS32: |
| case llvm::ELF::R_ARM_ABS16: |
| case llvm::ELF::R_ARM_ABS12: |
| case llvm::ELF::R_ARM_THM_ABS5: |
| case llvm::ELF::R_ARM_ABS8: |
| case llvm::ELF::R_ARM_BASE_ABS: |
| case llvm::ELF::R_ARM_MOVW_ABS_NC: |
| case llvm::ELF::R_ARM_MOVT_ABS: |
| case llvm::ELF::R_ARM_THM_MOVW_ABS_NC: |
| case llvm::ELF::R_ARM_THM_MOVT_ABS: |
| case llvm::ELF::R_ARM_ABS32_NOI: { |
| // Absolute relocation type, symbol may needs PLT entry or |
| // dynamic relocation entry |
| if (symbolNeedsPLT(*rsym, pLDInfo, pOutput)) { |
| // create plt for this symbol if it does not have one |
| if (!(rsym->reserved() & ReservePLT)){ |
| // Create .got section if it doesn't exist |
| if (NULL == m_pGOT) |
| createARMGOT(pLinker, pOutput); |
| // create .plt and .rel.plt if not exist |
| if (NULL == m_pPLT) |
| createARMPLTandRelPLT(pLinker, pOutput); |
| // Symbol needs PLT entry, we need to reserve a PLT entry |
| // and the corresponding GOT and dynamic relocation entry |
| // in .got and .rel.plt. (GOT entry will be reserved simultaneously |
| // when calling ARMPLT->reserveEntry()) |
| m_pPLT->reserveEntry(); |
| m_pRelPLT->reserveEntry(*m_pRelocFactory); |
| // set PLT bit |
| rsym->setReserved(rsym->reserved() | ReservePLT); |
| } |
| } |
| |
| if (symbolNeedsDynRel(*rsym, (rsym->reserved() & ReservePLT), |
| pLDInfo, pOutput, true)) { |
| // symbol needs dynamic relocation entry, reserve an entry in .rel.dyn |
| // create .rel.dyn section if not exist |
| if (NULL == m_pRelDyn) |
| createARMRelDyn(pLinker, pOutput); |
| m_pRelDyn->reserveEntry(*m_pRelocFactory); |
| if (symbolNeedsCopyReloc(pLinker.getLayout(), pReloc, *rsym, pLDInfo, |
| pOutput)) { |
| LDSymbol& cpy_sym = defineSymbolforCopyReloc(pLinker, *rsym); |
| addCopyReloc(*cpy_sym.resolveInfo()); |
| } |
| else { |
| checkValidReloc(pReloc, pLDInfo, pOutput); |
| // set Rel bit |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| } |
| } |
| return; |
| } |
| |
| case llvm::ELF::R_ARM_GOTOFF32: |
| case llvm::ELF::R_ARM_GOTOFF12: { |
| // A GOT section is needed |
| if (NULL == m_pGOT) |
| createARMGOT(pLinker, pOutput); |
| return; |
| } |
| |
| case llvm::ELF::R_ARM_BASE_PREL: |
| case llvm::ELF::R_ARM_THM_MOVW_BREL_NC: |
| case llvm::ELF::R_ARM_THM_MOVW_BREL: |
| case llvm::ELF::R_ARM_THM_MOVT_BREL: |
| // FIXME: Currently we only support these relocations against |
| // symbol _GLOBAL_OFFSET_TABLE_ |
| if (rsym != m_pGOTSymbol->resolveInfo()) { |
| fatal(diag::base_relocation) << (int)pReloc.type() << rsym->name() |
| << "mclinker@googlegroups.com"; |
| } |
| case llvm::ELF::R_ARM_REL32: |
| case llvm::ELF::R_ARM_LDR_PC_G0: |
| case llvm::ELF::R_ARM_SBREL32: |
| case llvm::ELF::R_ARM_THM_PC8: |
| case llvm::ELF::R_ARM_MOVW_PREL_NC: |
| case llvm::ELF::R_ARM_MOVT_PREL: |
| case llvm::ELF::R_ARM_THM_MOVW_PREL_NC: |
| case llvm::ELF::R_ARM_THM_MOVT_PREL: |
| case llvm::ELF::R_ARM_THM_ALU_PREL_11_0: |
| case llvm::ELF::R_ARM_THM_PC12: |
| case llvm::ELF::R_ARM_REL32_NOI: |
| case llvm::ELF::R_ARM_ALU_PC_G0_NC: |
| case llvm::ELF::R_ARM_ALU_PC_G0: |
| case llvm::ELF::R_ARM_ALU_PC_G1_NC: |
| case llvm::ELF::R_ARM_ALU_PC_G1: |
| case llvm::ELF::R_ARM_ALU_PC_G2: |
| case llvm::ELF::R_ARM_LDR_PC_G1: |
| case llvm::ELF::R_ARM_LDR_PC_G2: |
| case llvm::ELF::R_ARM_LDRS_PC_G0: |
| case llvm::ELF::R_ARM_LDRS_PC_G1: |
| case llvm::ELF::R_ARM_LDRS_PC_G2: |
| case llvm::ELF::R_ARM_LDC_PC_G0: |
| case llvm::ELF::R_ARM_LDC_PC_G1: |
| case llvm::ELF::R_ARM_LDC_PC_G2: |
| case llvm::ELF::R_ARM_ALU_SB_G0_NC: |
| case llvm::ELF::R_ARM_ALU_SB_G0: |
| case llvm::ELF::R_ARM_ALU_SB_G1_NC: |
| case llvm::ELF::R_ARM_ALU_SB_G1: |
| case llvm::ELF::R_ARM_ALU_SB_G2: |
| case llvm::ELF::R_ARM_LDR_SB_G0: |
| case llvm::ELF::R_ARM_LDR_SB_G1: |
| case llvm::ELF::R_ARM_LDR_SB_G2: |
| case llvm::ELF::R_ARM_LDRS_SB_G0: |
| case llvm::ELF::R_ARM_LDRS_SB_G1: |
| case llvm::ELF::R_ARM_LDRS_SB_G2: |
| case llvm::ELF::R_ARM_LDC_SB_G0: |
| case llvm::ELF::R_ARM_LDC_SB_G1: |
| case llvm::ELF::R_ARM_LDC_SB_G2: |
| case llvm::ELF::R_ARM_MOVW_BREL_NC: |
| case llvm::ELF::R_ARM_MOVT_BREL: |
| case llvm::ELF::R_ARM_MOVW_BREL: { |
| // Relative addressing relocation, may needs dynamic relocation |
| if (symbolNeedsDynRel(*rsym, (rsym->reserved() & ReservePLT), |
| pLDInfo, pOutput, false)) { |
| // symbol needs dynamic relocation entry, reserve an entry in .rel.dyn |
| // create .rel.dyn section if not exist |
| if (NULL == m_pRelDyn) |
| createARMRelDyn(pLinker, pOutput); |
| m_pRelDyn->reserveEntry(*m_pRelocFactory); |
| if (symbolNeedsCopyReloc(pLinker.getLayout(), pReloc, *rsym, pLDInfo, |
| pOutput)) { |
| LDSymbol& cpy_sym = defineSymbolforCopyReloc(pLinker, *rsym); |
| addCopyReloc(*cpy_sym.resolveInfo()); |
| } |
| else { |
| checkValidReloc(pReloc, pLDInfo, pOutput); |
| // set Rel bit |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| } |
| } |
| return; |
| } |
| |
| case llvm::ELF::R_ARM_THM_CALL: |
| case llvm::ELF::R_ARM_PLT32: |
| case llvm::ELF::R_ARM_CALL: |
| case llvm::ELF::R_ARM_JUMP24: |
| case llvm::ELF::R_ARM_THM_JUMP24: |
| case llvm::ELF::R_ARM_SBREL31: |
| case llvm::ELF::R_ARM_PREL31: |
| case llvm::ELF::R_ARM_THM_JUMP19: |
| case llvm::ELF::R_ARM_THM_JUMP6: |
| case llvm::ELF::R_ARM_THM_JUMP11: |
| case llvm::ELF::R_ARM_THM_JUMP8: { |
| // These are branch relocation (except PREL31) |
| // A PLT entry is needed when building shared library |
| |
| // return if we already create plt for this symbol |
| if (rsym->reserved() & ReservePLT) |
| return; |
| |
| // if symbol is defined in the ouput file and it's not |
| // preemptible, no need plt |
| if (rsym->isDefine() && !rsym->isDyn() && |
| !isSymbolPreemptible(*rsym, pLDInfo, pOutput)) { |
| return; |
| } |
| |
| // Create .got section if it doesn't exist |
| if (NULL == m_pGOT) |
| createARMGOT(pLinker, pOutput); |
| |
| // create .plt and .rel.plt if not exist |
| if (NULL == m_pPLT) |
| createARMPLTandRelPLT(pLinker, pOutput); |
| // Symbol needs PLT entry, we need to reserve a PLT entry |
| // and the corresponding GOT and dynamic relocation entry |
| // in .got and .rel.plt. (GOT entry will be reserved simultaneously |
| // when calling ARMPLT->reserveEntry()) |
| m_pPLT->reserveEntry(); |
| m_pRelPLT->reserveEntry(*m_pRelocFactory); |
| // set PLT bit |
| rsym->setReserved(rsym->reserved() | ReservePLT); |
| return; |
| } |
| |
| // Set R_ARM_TARGET2 to R_ARM_GOT_PREL |
| // Ref: GNU gold 1.11 arm.cc, line 9892 |
| // FIXME: R_ARM_TARGET2 should be set by option --target2 |
| case llvm::ELF::R_ARM_TARGET2: |
| pReloc.setType(llvm::ELF::R_ARM_GOT_PREL); |
| case llvm::ELF::R_ARM_GOT_BREL: |
| case llvm::ELF::R_ARM_GOT_ABS: |
| case llvm::ELF::R_ARM_GOT_PREL: { |
| // Symbol needs GOT entry, reserve entry in .got |
| // return if we already create GOT for this symbol |
| if (rsym->reserved() & (ReserveGOT | GOTRel)) |
| return; |
| if (NULL == m_pGOT) |
| createARMGOT(pLinker, pOutput); |
| m_pGOT->reserveEntry(); |
| // If building shared object or the symbol is undefined, a dynamic |
| // relocation is needed to relocate this GOT entry. Reserve an |
| // entry in .rel.dyn |
| if (Output::DynObj == pOutput.type() || rsym->isUndef() || rsym->isDyn()) { |
| // create .rel.dyn section if not exist |
| if (NULL == m_pRelDyn) |
| createARMRelDyn(pLinker, pOutput); |
| m_pRelDyn->reserveEntry(*m_pRelocFactory); |
| // set GOTRel bit |
| rsym->setReserved(rsym->reserved() | GOTRel); |
| return; |
| } |
| // set GOT bit |
| rsym->setReserved(rsym->reserved() | ReserveGOT); |
| return; |
| } |
| |
| case llvm::ELF::R_ARM_COPY: |
| case llvm::ELF::R_ARM_GLOB_DAT: |
| case llvm::ELF::R_ARM_JUMP_SLOT: |
| case llvm::ELF::R_ARM_RELATIVE: { |
| // These are relocation type for dynamic linker, shold not |
| // appear in object file. |
| fatal(diag::dynamic_relocation) << (int)pReloc.type(); |
| break; |
| } |
| default: { |
| break; |
| } |
| } // end switch |
| } |
| |
| void ARMGNULDBackend::scanRelocation(Relocation& pReloc, |
| const LDSymbol& pInputSym, |
| MCLinker& pLinker, |
| const MCLDInfo& pLDInfo, |
| const Output& pOutput, |
| const LDSection& pSection) |
| { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| assert(NULL != rsym && "ResolveInfo of relocation not set while scanRelocation"); |
| |
| assert(NULL != pSection.getLink()); |
| if (0 == (pSection.getLink()->flag() & llvm::ELF::SHF_ALLOC)) { |
| if (rsym->isLocal()) { |
| updateAddend(pReloc, pInputSym, pLinker.getLayout()); |
| } |
| return; |
| } |
| |
| // Scan relocation type to determine if an GOT/PLT/Dynamic Relocation |
| // entries should be created. |
| // FIXME: Below judgements concern only .so is generated as output |
| // FIXME: Below judgements concern nothing about TLS related relocation |
| |
| // A refernece to symbol _GLOBAL_OFFSET_TABLE_ implies that a .got section |
| // is needed |
| if (NULL == m_pGOT && NULL != m_pGOTSymbol) { |
| if (rsym == m_pGOTSymbol->resolveInfo()) { |
| createARMGOT(pLinker, pOutput); |
| } |
| } |
| |
| // rsym is local |
| if (rsym->isLocal()) |
| scanLocalReloc(pReloc, pInputSym, pLinker, pLDInfo, pOutput); |
| |
| // rsym is external |
| else |
| scanGlobalReloc(pReloc, pInputSym, pLinker, pLDInfo, pOutput); |
| |
| } |
| |
| uint64_t ARMGNULDBackend::emitSectionData(const Output& pOutput, |
| const LDSection& pSection, |
| const MCLDInfo& pInfo, |
| const Layout& pLayout, |
| MemoryRegion& pRegion) const |
| { |
| assert(pRegion.size() && "Size of MemoryRegion is zero!"); |
| |
| const ELFFileFormat* file_format = getOutputFormat(pOutput); |
| |
| if (&pSection == m_pAttributes || |
| &pSection == m_pEXIDX || |
| &pSection == m_pEXTAB) { |
| // FIXME: Currently Emitting .ARM.attributes, .ARM.exidx, and .ARM.extab |
| // directly from the input file. |
| const SectionData* sect_data = pSection.getSectionData(); |
| SectionData::const_iterator frag_iter, frag_end = sect_data->end(); |
| uint8_t* out_offset = pRegion.start(); |
| for (frag_iter = sect_data->begin(); frag_iter != frag_end; ++frag_iter) { |
| size_t size = computeFragmentSize(pLayout, *frag_iter); |
| switch(frag_iter->getKind()) { |
| case Fragment::Region: { |
| const RegionFragment& region_frag = |
| llvm::cast<RegionFragment>(*frag_iter); |
| const uint8_t* start = region_frag.getRegion().start(); |
| memcpy(out_offset, start, size); |
| break; |
| } |
| case Fragment::Alignment: { |
| AlignFragment& align_frag = llvm::cast<AlignFragment>(*frag_iter); |
| uint64_t count = size / align_frag.getValueSize(); |
| switch (align_frag.getValueSize()) { |
| case 1u: |
| std::memset(out_offset, align_frag.getValue(), count); |
| break; |
| default: |
| llvm::report_fatal_error( |
| "unsupported value size for align fragment emission yet.\n"); |
| break; |
| } // end switch |
| break; |
| } |
| default: |
| llvm::report_fatal_error("unsupported fragment type.\n"); |
| break; |
| } // end switch |
| out_offset += size; |
| } // end for |
| return pRegion.size(); |
| } // end if |
| |
| if (&pSection == &(file_format->getPLT())) { |
| assert(NULL != m_pPLT && "emitSectionData failed, m_pPLT is NULL!"); |
| uint64_t result = m_pPLT->emit(pRegion); |
| return result; |
| } |
| |
| if (&pSection == &(file_format->getGOT())) { |
| assert(NULL != m_pGOT && "emitSectionData failed, m_pGOT is NULL!"); |
| uint64_t result = m_pGOT->emit(pRegion); |
| return result; |
| } |
| fatal(diag::unrecognized_output_sectoin) |
| << pSection.name() |
| << "mclinker@googlegroups.com"; |
| return 0x0; |
| } |
| |
| /// finalizeSymbol - finalize the symbol value |
| bool ARMGNULDBackend::finalizeTargetSymbols(MCLinker& pLinker, const Output& pOutput) |
| { |
| return true; |
| } |
| |
| 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( |
| pInput.fileOffset() + pInputSectHdr.offset(), pInputSectHdr.size()); |
| |
| SectionData& sect_data = pLinker.getOrCreateSectData(pInputSectHdr); |
| |
| Fragment* frag = NULL; |
| if (NULL == region) { |
| // If the input section's size is zero, we got a NULL region. |
| // use a virtual fill fragment |
| frag = new FillFragment(0x0, 0, 0); |
| } |
| else |
| frag = new RegionFragment(*region); |
| |
| uint64_t size = pLinker.getLayout().appendFragment(*frag, |
| sect_data, |
| pInputSectHdr.align()); |
| |
| out_sect.setSize(out_sect.size() + size); |
| return true; |
| } |
| |
| ARMGOT& ARMGNULDBackend::getGOT() |
| { |
| assert(NULL != m_pGOT && "GOT section not exist"); |
| return *m_pGOT; |
| } |
| |
| const ARMGOT& ARMGNULDBackend::getGOT() const |
| { |
| assert(NULL != m_pGOT && "GOT section not exist"); |
| return *m_pGOT; |
| } |
| |
| ARMPLT& ARMGNULDBackend::getPLT() |
| { |
| assert(NULL != m_pPLT && "PLT section not exist"); |
| return *m_pPLT; |
| } |
| |
| const ARMPLT& ARMGNULDBackend::getPLT() const |
| { |
| assert(NULL != m_pPLT && "PLT section not exist"); |
| return *m_pPLT; |
| } |
| |
| OutputRelocSection& ARMGNULDBackend::getRelDyn() |
| { |
| assert(NULL != m_pRelDyn && ".rel.dyn section not exist"); |
| return *m_pRelDyn; |
| } |
| |
| const OutputRelocSection& ARMGNULDBackend::getRelDyn() const |
| { |
| assert(NULL != m_pRelDyn && ".rel.dyn section not exist"); |
| return *m_pRelDyn; |
| } |
| |
| OutputRelocSection& ARMGNULDBackend::getRelPLT() |
| { |
| assert(NULL != m_pRelPLT && ".rel.plt section not exist"); |
| return *m_pRelPLT; |
| } |
| |
| const OutputRelocSection& ARMGNULDBackend::getRelPLT() const |
| { |
| assert(NULL != m_pRelPLT && ".rel.plt section not exist"); |
| return *m_pRelPLT; |
| } |
| |
| unsigned int |
| ARMGNULDBackend::getTargetSectionOrder(const Output& pOutput, |
| const LDSection& pSectHdr, |
| const MCLDInfo& pInfo) const |
| { |
| const ELFFileFormat* file_format = getOutputFormat(pOutput); |
| |
| if (&pSectHdr == &file_format->getGOT()) { |
| if (pInfo.options().hasNow()) |
| return SHO_RELRO_LAST; |
| return SHO_DATA; |
| } |
| |
| if (&pSectHdr == &file_format->getPLT()) |
| return SHO_PLT; |
| |
| if (&pSectHdr == m_pEXIDX || &pSectHdr == m_pEXTAB) { |
| // put ARM.exidx and ARM.extab in the same order of .eh_frame |
| return SHO_EXCEPTION; |
| } |
| |
| return SHO_UNDEFINED; |
| } |
| |
| namespace mcld { |
| |
| //===----------------------------------------------------------------------===// |
| /// createARMLDBackend - the help funtion to create corresponding ARMLDBackend |
| /// |
| TargetLDBackend* createARMLDBackend(const llvm::Target& pTarget, |
| const std::string& pTriple) |
| { |
| Triple theTriple(pTriple); |
| if (theTriple.isOSDarwin()) { |
| assert(0 && "MachO linker is not supported yet"); |
| /** |
| return new ARMMachOLDBackend(createARMMachOArchiveReader, |
| createARMMachOObjectReader, |
| createARMMachOObjectWriter); |
| **/ |
| } |
| if (theTriple.isOSWindows()) { |
| assert(0 && "COFF linker is not supported yet"); |
| /** |
| return new ARMCOFFLDBackend(createARMCOFFArchiveReader, |
| createARMCOFFObjectReader, |
| createARMCOFFObjectWriter); |
| **/ |
| } |
| return new ARMGNULDBackend(); |
| } |
| |
| } // namespace of mcld |
| |
| //============================= |
| // Force static initialization. |
| extern "C" void LLVMInitializeARMLDBackend() { |
| // Register the linker backend |
| mcld::TargetRegistry::RegisterTargetLDBackend(TheARMTarget, createARMLDBackend); |
| mcld::TargetRegistry::RegisterTargetLDBackend(TheThumbTarget, createARMLDBackend); |
| } |
| |
