| //===- 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 "ARMGNUInfo.h" |
| #include "ARMELFDynamic.h" |
| #include "ARMLDBackend.h" |
| #include "ARMRelocator.h" |
| #include "ARMToARMStub.h" |
| #include "ARMToTHMStub.h" |
| #include "THMToTHMStub.h" |
| #include "THMToARMStub.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/IRBuilder.h> |
| #include <mcld/LinkerConfig.h> |
| #include <mcld/Fragment/FillFragment.h> |
| #include <mcld/Fragment/AlignFragment.h> |
| #include <mcld/Fragment/RegionFragment.h> |
| #include <mcld/Fragment/FragmentLinker.h> |
| #include <mcld/Support/MemoryRegion.h> |
| #include <mcld/Support/MemoryArea.h> |
| #include <mcld/Support/MsgHandling.h> |
| #include <mcld/Support/TargetRegistry.h> |
| #include <mcld/Fragment/Stub.h> |
| #include <mcld/LD/BranchIslandFactory.h> |
| #include <mcld/LD/StubFactory.h> |
| #include <mcld/Object/ObjectBuilder.h> |
| #include <mcld/Fragment/NullFragment.h> |
| #include <mcld/LD/LDContext.h> |
| #include <mcld/Target/GNUInfo.h> |
| |
| using namespace mcld; |
| |
| //===----------------------------------------------------------------------===// |
| // ARMGNULDBackend |
| //===----------------------------------------------------------------------===// |
| ARMGNULDBackend::ARMGNULDBackend(const LinkerConfig& pConfig, GNUInfo* pInfo) |
| : GNULDBackend(pConfig, pInfo), |
| m_pRelocator(NULL), |
| m_pGOT(NULL), |
| m_pPLT(NULL), |
| m_pRelDyn(NULL), |
| m_pRelPLT(NULL), |
| m_pDynamic(NULL), |
| m_pGOTSymbol(NULL), |
| m_pEXIDXStart(NULL), |
| m_pEXIDXEnd(NULL), |
| m_pEXIDX(NULL), |
| m_pEXTAB(NULL), |
| m_pAttributes(NULL) { |
| } |
| |
| ARMGNULDBackend::~ARMGNULDBackend() |
| { |
| delete m_pRelocator; |
| delete m_pGOT; |
| delete m_pPLT; |
| delete m_pRelDyn; |
| delete m_pRelPLT; |
| delete m_pDynamic; |
| } |
| |
| void ARMGNULDBackend::initTargetSections(Module& pModule, ObjectBuilder& pBuilder) |
| { |
| // FIXME: Currently we set exidx and extab to "Exception" and directly emit |
| // them from input |
| m_pEXIDX = pBuilder.CreateSection(".ARM.exidx", |
| LDFileFormat::Target, |
| llvm::ELF::SHT_ARM_EXIDX, |
| llvm::ELF::SHF_ALLOC | llvm::ELF::SHF_LINK_ORDER, |
| config().targets().bitclass() / 8); |
| m_pEXTAB = pBuilder.CreateSection(".ARM.extab", |
| LDFileFormat::Target, |
| llvm::ELF::SHT_PROGBITS, |
| llvm::ELF::SHF_ALLOC, |
| 0x1); |
| m_pAttributes = pBuilder.CreateSection(".ARM.attributes", |
| LDFileFormat::Target, |
| llvm::ELF::SHT_ARM_ATTRIBUTES, |
| 0x0, |
| 0x1); |
| |
| if (LinkerConfig::Object != config().codeGenType()) { |
| ELFFileFormat* file_format = getOutputFormat(); |
| |
| // initialize .got |
| LDSection& got = file_format->getGOT(); |
| m_pGOT = new ARMGOT(got); |
| |
| // initialize .plt |
| LDSection& plt = file_format->getPLT(); |
| m_pPLT = new ARMPLT(plt, *m_pGOT); |
| |
| // initialize .rel.plt |
| LDSection& relplt = file_format->getRelPlt(); |
| relplt.setLink(&plt); |
| // create SectionData and ARMRelDynSection |
| m_pRelPLT = new OutputRelocSection(pModule, relplt); |
| |
| // initialize .rel.dyn |
| LDSection& reldyn = file_format->getRelDyn(); |
| m_pRelDyn = new OutputRelocSection(pModule, reldyn); |
| } |
| } |
| |
| void ARMGNULDBackend::initTargetSymbols(FragmentLinker& pLinker) |
| { |
| // Define the symbol _GLOBAL_OFFSET_TABLE_ if there is a symbol with the |
| // same name in input |
| m_pGOTSymbol = pLinker.defineSymbol<FragmentLinker::AsRefered, FragmentLinker::Resolve>( |
| "_GLOBAL_OFFSET_TABLE_", |
| false, |
| ResolveInfo::Object, |
| ResolveInfo::Define, |
| ResolveInfo::Local, |
| 0x0, // size |
| 0x0, // value |
| FragmentRef::Null(), // FragRef |
| ResolveInfo::Hidden); |
| |
| FragmentRef* exidx_start = NULL; |
| FragmentRef* exidx_end = NULL; |
| ResolveInfo::Desc desc = ResolveInfo::Undefined; |
| if (NULL != m_pEXIDX && 0x0 != m_pEXIDX->size()) { |
| exidx_start = FragmentRef::Create(m_pEXIDX->getSectionData()->front(), 0x0); |
| exidx_end = FragmentRef::Create(m_pEXIDX->getSectionData()->back(), 0x0); |
| desc = ResolveInfo::Define; |
| } |
| else { |
| exidx_start = FragmentRef::Null(); |
| exidx_end = FragmentRef::Null(); |
| } |
| m_pEXIDXStart = |
| pLinker.defineSymbol<FragmentLinker::Force, |
| FragmentLinker::Resolve>("__exidx_start", |
| false, |
| ResolveInfo::NoType, |
| desc, // ResolveInfo::Desc |
| ResolveInfo::Global, |
| 0x0, // size |
| 0x0, // value |
| exidx_start, // FragRef |
| ResolveInfo::Hidden); |
| |
| m_pEXIDXEnd = |
| pLinker.defineSymbol<FragmentLinker::Force, |
| FragmentLinker::Resolve>("__exidx_end", |
| false, |
| ResolveInfo::NoType, |
| desc, //ResolveInfo::Desc |
| ResolveInfo::Global, |
| 0x0, // size |
| 0x0, // value |
| exidx_end, // FragRef |
| ResolveInfo::Hidden); |
| } |
| |
| bool ARMGNULDBackend::initRelocator(const FragmentLinker& pLinker) |
| { |
| if (NULL == m_pRelocator) { |
| m_pRelocator = new ARMRelocator(*this); |
| m_pRelocator->setFragmentLinker(pLinker); |
| } |
| return true; |
| } |
| |
| Relocator* ARMGNULDBackend::getRelocator() |
| { |
| assert(NULL != m_pRelocator); |
| return m_pRelocator; |
| } |
| |
| void ARMGNULDBackend::doPreLayout(FragmentLinker& pLinker) |
| { |
| // set .got size |
| // when building shared object, the .got section is must |
| if (LinkerConfig::Object != config().codeGenType()) { |
| if (LinkerConfig::DynObj == config().codeGenType() || |
| m_pGOT->hasGOT1() || |
| NULL != m_pGOTSymbol) { |
| m_pGOT->finalizeSectionSize(); |
| defineGOTSymbol(pLinker); |
| } |
| |
| // set .plt size |
| if (m_pPLT->hasPLT1()) |
| m_pPLT->finalizeSectionSize(); |
| |
| ELFFileFormat* file_format = getOutputFormat(); |
| // set .rel.dyn size |
| if (!m_pRelDyn->empty()) |
| file_format->getRelDyn().setSize( |
| m_pRelDyn->numOfRelocs() * getRelEntrySize()); |
| |
| // set .rel.plt size |
| if (!m_pRelPLT->empty()) |
| file_format->getRelPlt().setSize( |
| m_pRelPLT->numOfRelocs() * getRelEntrySize()); |
| } |
| } |
| |
| void ARMGNULDBackend::doPostLayout(Module& pModule, |
| FragmentLinker& pLinker) |
| { |
| const ELFFileFormat *file_format = getOutputFormat(); |
| |
| // 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 (LinkerConfig::DynObj == config().codeGenType()) |
| 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, config()); |
| |
| 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::defineGOTSymbol(FragmentLinker& pLinker) |
| { |
| // define symbol _GLOBAL_OFFSET_TABLE_ when .got create |
| if (m_pGOTSymbol != NULL) { |
| pLinker.defineSymbol<FragmentLinker::Force, FragmentLinker::Unresolve>( |
| "_GLOBAL_OFFSET_TABLE_", |
| false, |
| ResolveInfo::Object, |
| ResolveInfo::Define, |
| ResolveInfo::Local, |
| 0x0, // size |
| 0x0, // value |
| FragmentRef::Create(*(m_pGOT->begin()), 0x0), |
| ResolveInfo::Hidden); |
| } |
| else { |
| m_pGOTSymbol = pLinker.defineSymbol<FragmentLinker::Force, FragmentLinker::Resolve>( |
| "_GLOBAL_OFFSET_TABLE_", |
| false, |
| ResolveInfo::Object, |
| ResolveInfo::Define, |
| ResolveInfo::Local, |
| 0x0, // size |
| 0x0, // value |
| FragmentRef::Create(*(m_pGOT->begin()), 0x0), |
| ResolveInfo::Hidden); |
| } |
| |
| } |
| |
| void ARMGNULDBackend::addCopyReloc(ResolveInfo& pSym) |
| { |
| Relocation& rel_entry = *m_pRelDyn->consumeEntry(); |
| rel_entry.setType(llvm::ELF::R_ARM_COPY); |
| assert(pSym.outSymbol()->hasFragRef()); |
| rel_entry.targetRef().assign(*pSym.outSymbol()->fragRef()); |
| rel_entry.setSymInfo(&pSym); |
| } |
| |
| /// defineSymbolForCopyReloc |
| /// 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. |
| /// This is executed at scan relocation stage. |
| LDSymbol& |
| ARMGNULDBackend::defineSymbolforCopyReloc(FragmentLinker& pLinker, |
| const ResolveInfo& pSym) |
| { |
| // get or create corresponding BSS LDSection |
| LDSection* bss_sect_hdr = NULL; |
| ELFFileFormat* file_format = getOutputFormat(); |
| if (ResolveInfo::ThreadLocal == pSym.type()) |
| bss_sect_hdr = &file_format->getTBSS(); |
| else |
| bss_sect_hdr = &file_format->getBSS(); |
| |
| // get or create corresponding BSS SectionData |
| SectionData* bss_data = NULL; |
| if (bss_sect_hdr->hasSectionData()) |
| bss_data = bss_sect_hdr->getSectionData(); |
| else |
| bss_data = IRBuilder::CreateSectionData(*bss_sect_hdr); |
| |
| // Determine the alignment by the symbol value |
| // FIXME: here we use the largest alignment |
| uint32_t addralign = config().targets().bitclass() / 8; |
| |
| // allocate space in BSS for the copy symbol |
| Fragment* frag = new FillFragment(0x0, 1, pSym.size()); |
| uint64_t size = ObjectBuilder::AppendFragment(*frag, |
| *bss_data, |
| 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<FragmentLinker::Force, FragmentLinker::Resolve>( |
| pSym.name(), |
| false, |
| (ResolveInfo::Type)pSym.type(), |
| ResolveInfo::Define, |
| binding, |
| pSym.size(), // size |
| 0x0, // value |
| FragmentRef::Create(*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 FragmentLinker& pLinker) const |
| { |
| // If not PIC object, no relocation type is invalid |
| if (!pLinker.isOutputPIC()) |
| 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::scanLocalReloc(Relocation& pReloc, |
| FragmentLinker& pLinker) |
| { |
| // 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_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 (pLinker.isOutputPIC()) { |
| m_pRelDyn->reserveEntry(); |
| // 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 (pLinker.isOutputPIC()) { |
| error(diag::non_pic_relocation) << (int)pReloc.type() |
| << pReloc.symInfo()->name(); |
| } |
| return; |
| } |
| case llvm::ELF::R_ARM_GOTOFF32: |
| case llvm::ELF::R_ARM_GOTOFF12: { |
| // FIXME: A GOT section is needed |
| 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; |
| m_pGOT->reserveGOT(); |
| // If building PIC object, a dynamic relocation with |
| // type RELATIVE is needed to relocate this GOT entry. |
| // Reserve an entry in .rel.dyn |
| if (pLinker.isOutputPIC()) { |
| // create .rel.dyn section if not exist |
| m_pRelDyn->reserveEntry(); |
| // 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, |
| FragmentLinker& pLinker) |
| { |
| // 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(pLinker, *rsym)) { |
| // create plt for this symbol if it does not have one |
| if (!(rsym->reserved() & ReservePLT)){ |
| // 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(); |
| // set PLT bit |
| rsym->setReserved(rsym->reserved() | ReservePLT); |
| } |
| } |
| |
| if (symbolNeedsDynRel( |
| pLinker, *rsym, (rsym->reserved() & ReservePLT), true)) { |
| // symbol needs dynamic relocation entry, reserve an entry in .rel.dyn |
| m_pRelDyn->reserveEntry(); |
| if (symbolNeedsCopyReloc(pLinker, pReloc, *rsym)) { |
| LDSymbol& cpy_sym = defineSymbolforCopyReloc(pLinker, *rsym); |
| addCopyReloc(*cpy_sym.resolveInfo()); |
| } |
| else { |
| checkValidReloc(pReloc, pLinker); |
| // set Rel bit |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| } |
| } |
| return; |
| } |
| |
| case llvm::ELF::R_ARM_GOTOFF32: |
| case llvm::ELF::R_ARM_GOTOFF12: { |
| // FIXME: A GOT section is needed |
| 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( |
| pLinker, *rsym, (rsym->reserved() & ReservePLT), false)) { |
| // symbol needs dynamic relocation entry, reserve an entry in .rel.dyn |
| m_pRelDyn->reserveEntry(); |
| if (symbolNeedsCopyReloc(pLinker, pReloc, *rsym)) { |
| LDSymbol& cpy_sym = defineSymbolforCopyReloc(pLinker, *rsym); |
| addCopyReloc(*cpy_sym.resolveInfo()); |
| } |
| else { |
| checkValidReloc(pReloc, pLinker); |
| // 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 the symbol's value can be decided at link time, then no need plt |
| if (symbolFinalValueIsKnown(pLinker, *rsym)) |
| return; |
| |
| // if symbol is defined in the ouput file and it's not |
| // preemptible, no need plt |
| if (rsym->isDefine() && !rsym->isDyn() && |
| !isSymbolPreemptible(*rsym)) { |
| return; |
| } |
| |
| // 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(); |
| // 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; |
| m_pGOT->reserveGOT(); |
| // if the symbol cannot be fully resolved at link time, then we need a |
| // dynamic relocation |
| if (!symbolFinalValueIsKnown(pLinker, *rsym)) { |
| m_pRelDyn->reserveEntry(); |
| // 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, |
| FragmentLinker& pLinker, |
| Module& pModule, |
| const LDSection& pSection) |
| { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| assert(NULL != rsym && "ResolveInfo of relocation not set while scanRelocation"); |
| |
| pReloc.updateAddend(); |
| if (0 == (pSection.flag() & llvm::ELF::SHF_ALLOC)) |
| return; |
| |
| // Scan relocation type to determine if an GOT/PLT/Dynamic Relocation |
| // entries should be created. |
| // FIXME: Below judgements concern nothing about TLS related relocation |
| |
| // rsym is local |
| if (rsym->isLocal()) |
| scanLocalReloc(pReloc, pLinker); |
| |
| // rsym is external |
| else |
| scanGlobalReloc(pReloc, pLinker); |
| |
| // check if we shoule issue undefined reference for the relocation target |
| // symbol |
| if (rsym->isUndef() && !rsym->isDyn() && !rsym->isWeak() && !rsym->isNull()) |
| fatal(diag::undefined_reference) << rsym->name(); |
| |
| if ((rsym->reserved() & ReserveRel) != 0x0) { |
| // set hasTextRelSection if needed |
| checkAndSetHasTextRel(pSection); |
| } |
| } |
| |
| uint64_t ARMGNULDBackend::emitSectionData(const LDSection& pSection, |
| MemoryRegion& pRegion) const |
| { |
| assert(pRegion.size() && "Size of MemoryRegion is zero!"); |
| |
| const ELFFileFormat* file_format = getOutputFormat(); |
| |
| 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 = frag_iter->size(); |
| switch(frag_iter->getKind()) { |
| case Fragment::Fillment: { |
| const FillFragment& fill_frag = |
| llvm::cast<FillFragment>(*frag_iter); |
| if (0 == fill_frag.getValueSize()) { |
| // virtual fillment, ignore it. |
| break; |
| } |
| |
| memset(out_offset, fill_frag.getValue(), fill_frag.size()); |
| break; |
| } |
| 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; |
| } |
| case Fragment::Null: { |
| assert(0x0 == size); |
| 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(FragmentLinker& pLinker) |
| { |
| if (NULL != m_pEXIDXStart) { |
| if (NULL != m_pEXIDX && 0x0 != m_pEXIDX->size()) |
| m_pEXIDXStart->setValue(m_pEXIDX->addr()); |
| } |
| |
| if (NULL != m_pEXIDXEnd) { |
| if (NULL != m_pEXIDX && 0x0 != m_pEXIDX->size()) |
| m_pEXIDXEnd->setValue(m_pEXIDX->addr() + m_pEXIDX->size()); |
| } |
| return true; |
| } |
| |
| bool ARMGNULDBackend::mergeSection(Module& pModule, LDSection& pSection) |
| { |
| switch (pSection.type()) { |
| case llvm::ELF::SHT_ARM_ATTRIBUTES: { |
| // FIXME: (Luba) |
| // Handle ARM attributes in the right way. |
| // In current milestone, FragmentLinker 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 != m_pAttributes->size()) |
| return true; |
| |
| // First time we meet a ARM attributes section. |
| SectionData* sd = IRBuilder::CreateSectionData(*m_pAttributes); |
| ObjectBuilder::MoveSectionData(*pSection.getSectionData(), *sd); |
| return true; |
| } |
| default: { |
| ObjectBuilder builder(config(), pModule); |
| return builder.MergeSection(pSection); |
| } |
| } // end of switch |
| return true; |
| } |
| |
| bool ARMGNULDBackend::readSection(Input& pInput, SectionData& pSD) |
| { |
| Fragment* frag = NULL; |
| uint32_t offset = pInput.fileOffset() + pSD.getSection().offset(); |
| uint32_t size = pSD.getSection().size(); |
| |
| MemoryRegion* region = pInput.memArea()->request(offset, size); |
| 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); |
| } |
| |
| ObjectBuilder::AppendFragment(*frag, pSD); |
| 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 LDSection& pSectHdr) const |
| { |
| const ELFFileFormat* file_format = getOutputFormat(); |
| |
| if (&pSectHdr == &file_format->getGOT()) { |
| if (config().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; |
| } |
| |
| /// doRelax |
| bool ARMGNULDBackend::doRelax(Module& pModule, FragmentLinker& pLinker, bool& pFinished) |
| { |
| assert(NULL != getStubFactory() && NULL != getBRIslandFactory()); |
| |
| bool isRelaxed = false; |
| ELFFileFormat* file_format = getOutputFormat(); |
| // check branch relocs and create the related stubs if needed |
| Module::obj_iterator input, inEnd = pModule.obj_end(); |
| for (input = pModule.obj_begin(); input != inEnd; ++input) { |
| LDContext::sect_iterator rs, rsEnd = (*input)->context()->relocSectEnd(); |
| for (rs = (*input)->context()->relocSectBegin(); rs != rsEnd; ++rs) { |
| if (LDFileFormat::Ignore == (*rs)->kind() || !(*rs)->hasRelocData()) |
| continue; |
| RelocData::iterator reloc, rEnd = (*rs)->getRelocData()->end(); |
| for (reloc = (*rs)->getRelocData()->begin(); reloc != rEnd; ++reloc) { |
| Relocation* relocation = llvm::cast<Relocation>(reloc); |
| |
| switch (relocation->type()) { |
| case llvm::ELF::R_ARM_CALL: |
| case llvm::ELF::R_ARM_JUMP24: |
| case llvm::ELF::R_ARM_PLT32: |
| case llvm::ELF::R_ARM_THM_CALL: |
| case llvm::ELF::R_ARM_THM_XPC22: |
| case llvm::ELF::R_ARM_THM_JUMP24: |
| case llvm::ELF::R_ARM_THM_JUMP19: |
| case llvm::ELF::R_ARM_V4BX: { |
| // calculate the possible symbol value |
| uint64_t sym_value = 0x0; |
| LDSymbol* symbol = relocation->symInfo()->outSymbol(); |
| if (symbol->hasFragRef()) { |
| uint64_t value = symbol->fragRef()->getOutputOffset(); |
| uint64_t addr = |
| symbol->fragRef()->frag()->getParent()->getSection().addr(); |
| sym_value = addr + value; |
| } |
| if (relocation->symInfo()->isGlobal() && |
| (relocation->symInfo()->reserved() & ReservePLT) != 0x0) { |
| // FIXME: we need to find out the address of the specific plt entry |
| assert(file_format->hasPLT()); |
| sym_value = file_format->getPLT().addr(); |
| } |
| |
| Stub* stub = getStubFactory()->create(*relocation, // relocation |
| sym_value, // symbol value |
| pLinker, |
| *getBRIslandFactory()); |
| if (NULL != stub) { |
| assert(NULL != stub->symInfo()); |
| // increase the size of .symtab and .strtab |
| LDSection& symtab = file_format->getSymTab(); |
| LDSection& strtab = file_format->getStrTab(); |
| if (config().targets().is32Bits()) |
| symtab.setSize(symtab.size() + sizeof(llvm::ELF::Elf32_Sym)); |
| else |
| symtab.setSize(symtab.size() + sizeof(llvm::ELF::Elf64_Sym)); |
| strtab.setSize(strtab.size() + stub->symInfo()->nameSize() + 1); |
| |
| isRelaxed = true; |
| } |
| break; |
| } |
| default: |
| break; |
| } // end of switch |
| |
| } // for all relocations |
| } // for all relocation section |
| } // for all inputs |
| |
| // find the first fragment w/ invalid offset due to stub insertion |
| Fragment* invalid = NULL; |
| pFinished = true; |
| for (BranchIslandFactory::iterator island = getBRIslandFactory()->begin(), |
| island_end = getBRIslandFactory()->end(); island != island_end; ++island) { |
| if ((*island).end() == file_format->getText().getSectionData()->end()) |
| break; |
| |
| Fragment* exit = (*island).end(); |
| if (((*island).offset() + (*island).size()) > exit->getOffset()) { |
| invalid = exit; |
| pFinished = false; |
| break; |
| } |
| } |
| |
| // reset the offset of invalid fragments |
| while (NULL != invalid) { |
| invalid->setOffset(invalid->getPrevNode()->getOffset() + |
| invalid->getPrevNode()->size()); |
| invalid = invalid->getNextNode(); |
| } |
| |
| // reset the size of .text |
| if (isRelaxed) { |
| file_format->getText().setSize( |
| file_format->getText().getSectionData()->back().getOffset() + |
| file_format->getText().getSectionData()->back().size()); |
| } |
| return isRelaxed; |
| } |
| |
| /// initTargetStubs |
| bool ARMGNULDBackend::initTargetStubs(FragmentLinker& pLinker) |
| { |
| if (NULL != getStubFactory()) { |
| getStubFactory()->addPrototype(new ARMToARMStub(pLinker.isOutputPIC())); |
| getStubFactory()->addPrototype(new ARMToTHMStub(pLinker.isOutputPIC())); |
| getStubFactory()->addPrototype(new THMToTHMStub(pLinker.isOutputPIC())); |
| getStubFactory()->addPrototype(new THMToARMStub(pLinker.isOutputPIC())); |
| return true; |
| } |
| return false; |
| } |
| |
| /// doCreateProgramHdrs - backend can implement this function to create the |
| /// target-dependent segments |
| void ARMGNULDBackend::doCreateProgramHdrs(Module& pModule, |
| const FragmentLinker& pLinker) |
| { |
| if (NULL != m_pEXIDX && 0x0 != m_pEXIDX->size()) { |
| // make PT_ARM_EXIDX |
| ELFSegment* exidx_seg = elfSegmentTable().produce(llvm::ELF::PT_ARM_EXIDX, |
| llvm::ELF::PF_R); |
| exidx_seg->addSection(m_pEXIDX); |
| } |
| } |
| |
| namespace mcld { |
| |
| //===----------------------------------------------------------------------===// |
| /// createARMLDBackend - the help funtion to create corresponding ARMLDBackend |
| /// |
| TargetLDBackend* createARMLDBackend(const llvm::Target& pTarget, |
| const LinkerConfig& pConfig) |
| { |
| if (pConfig.targets().triple().isOSDarwin()) { |
| assert(0 && "MachO linker is not supported yet"); |
| /** |
| return new ARMMachOLDBackend(createARMMachOArchiveReader, |
| createARMMachOObjectReader, |
| createARMMachOObjectWriter); |
| **/ |
| } |
| if (pConfig.targets().triple().isOSWindows()) { |
| assert(0 && "COFF linker is not supported yet"); |
| /** |
| return new ARMCOFFLDBackend(createARMCOFFArchiveReader, |
| createARMCOFFObjectReader, |
| createARMCOFFObjectWriter); |
| **/ |
| } |
| return new ARMGNULDBackend(pConfig, new ARMGNUInfo(pConfig.targets().triple())); |
| } |
| |
| } // namespace of mcld |
| |
| //===----------------------------------------------------------------------===// |
| // Force static initialization. |
| //===----------------------------------------------------------------------===// |
| extern "C" void MCLDInitializeARMLDBackend() { |
| // Register the linker backend |
| mcld::TargetRegistry::RegisterTargetLDBackend(TheARMTarget, createARMLDBackend); |
| mcld::TargetRegistry::RegisterTargetLDBackend(TheThumbTarget, createARMLDBackend); |
| } |
| |
