| //===- AArch64Relocator.cpp ----------------------------------------------===// |
| // |
| // The MCLinker Project |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "mcld/LinkerConfig.h" |
| #include "mcld/IRBuilder.h" |
| #include "mcld/Support/MsgHandling.h" |
| #include "mcld/LD/LDSymbol.h" |
| #include "mcld/LD/ELFFileFormat.h" |
| #include "mcld/Object/ObjectBuilder.h" |
| |
| #include "AArch64Relocator.h" |
| #include "AArch64RelocationFunctions.h" |
| #include "AArch64RelocationHelpers.h" |
| |
| #include <llvm/ADT/Twine.h> |
| #include <llvm/Support/DataTypes.h> |
| #include <llvm/Support/ELF.h> |
| #include <llvm/Support/Host.h> |
| |
| namespace mcld { |
| |
| //===----------------------------------------------------------------------===// |
| // Relocation Functions and Tables |
| //===----------------------------------------------------------------------===// |
| DECL_AARCH64_APPLY_RELOC_FUNCS |
| |
| /// the prototype of applying function |
| typedef Relocator::Result (*ApplyFunctionType)(Relocation& pReloc, |
| AArch64Relocator& pParent); |
| |
| // the table entry of applying functions |
| class ApplyFunctionEntry { |
| public: |
| ApplyFunctionEntry() {} |
| ApplyFunctionEntry(ApplyFunctionType pFunc, |
| const char* pName, |
| size_t pSize = 0) |
| : func(pFunc), name(pName), size(pSize) {} |
| ApplyFunctionType func; |
| const char* name; |
| size_t size; |
| }; |
| typedef std::map<Relocator::Type, ApplyFunctionEntry> ApplyFunctionMap; |
| |
| static const ApplyFunctionMap::value_type ApplyFunctionList[] = { |
| DECL_AARCH64_APPLY_RELOC_FUNC_PTRS(ApplyFunctionMap::value_type, |
| ApplyFunctionEntry)}; |
| |
| // declare the table of applying functions |
| static ApplyFunctionMap ApplyFunctions(ApplyFunctionList, |
| ApplyFunctionList + |
| sizeof(ApplyFunctionList) / |
| sizeof(ApplyFunctionList[0])); |
| |
| //===----------------------------------------------------------------------===// |
| // AArch64Relocator |
| //===----------------------------------------------------------------------===// |
| AArch64Relocator::AArch64Relocator(AArch64GNULDBackend& pParent, |
| const LinkerConfig& pConfig) |
| : Relocator(pConfig), m_Target(pParent) { |
| } |
| |
| AArch64Relocator::~AArch64Relocator() { |
| } |
| |
| Relocator::Result AArch64Relocator::applyRelocation(Relocation& pRelocation) { |
| Relocation::Type type = pRelocation.type(); |
| // valid types are 0x0, 0x100-1032, and R_AARCH64_REWRITE_INSN |
| if ((type < 0x100 || type > 1032) && |
| (type != 0x0) && |
| (type != R_AARCH64_REWRITE_INSN)) { |
| return Relocator::Unknown; |
| } |
| assert(ApplyFunctions.find(type) != ApplyFunctions.end()); |
| return ApplyFunctions[type].func(pRelocation, *this); |
| } |
| |
| const char* AArch64Relocator::getName(Relocator::Type pType) const { |
| assert(ApplyFunctions.find(pType) != ApplyFunctions.end()); |
| return ApplyFunctions[pType].name; |
| } |
| |
| Relocator::Size AArch64Relocator::getSize(Relocation::Type pType) const { |
| return ApplyFunctions[pType].size; |
| } |
| |
| void AArch64Relocator::addCopyReloc(ResolveInfo& pSym) { |
| Relocation& rel_entry = *getTarget().getRelaDyn().create(); |
| rel_entry.setType(llvm::ELF::R_AARCH64_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& AArch64Relocator::defineSymbolforCopyReloc(IRBuilder& pBuilder, |
| const ResolveInfo& pSym) { |
| // get or create corresponding BSS LDSection |
| LDSection* bss_sect_hdr = NULL; |
| ELFFileFormat* file_format = getTarget().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 = pBuilder.AddSymbol<IRBuilder::Force, IRBuilder::Resolve>( |
| pSym.name(), |
| (ResolveInfo::Type)pSym.type(), |
| ResolveInfo::Define, |
| binding, |
| pSym.size(), // size |
| 0x0, // value |
| FragmentRef::Create(*frag, 0x0), |
| (ResolveInfo::Visibility)pSym.other()); |
| |
| return *cpy_sym; |
| } |
| |
| void AArch64Relocator::scanLocalReloc(Relocation& pReloc, |
| const LDSection& pSection) { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| switch (pReloc.type()) { |
| case llvm::ELF::R_AARCH64_ABS64: |
| // 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 (config().isCodeIndep()) { |
| // set Rel bit |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| getTarget().checkAndSetHasTextRel(*pSection.getLink()); |
| // set up the dyn rel directly |
| Relocation& reloc = helper_DynRela_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| llvm::ELF::R_AARCH64_RELATIVE, |
| *this); |
| getRelRelMap().record(pReloc, reloc); |
| } |
| return; |
| |
| case llvm::ELF::R_AARCH64_ABS32: |
| case llvm::ELF::R_AARCH64_ABS16: |
| // 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 (config().isCodeIndep()) { |
| // set up the dyn rel directly |
| Relocation& reloc = helper_DynRela_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| pReloc.type(), |
| *this); |
| getRelRelMap().record(pReloc, reloc); |
| // set Rel bit |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| getTarget().checkAndSetHasTextRel(*pSection.getLink()); |
| } |
| return; |
| |
| case llvm::ELF::R_AARCH64_ADR_GOT_PAGE: |
| case llvm::ELF::R_AARCH64_LD64_GOT_LO12_NC: { |
| // Symbol needs GOT entry, reserve entry in .got |
| // return if we already create GOT for this symbol |
| if (rsym->reserved() & ReserveGOT) |
| return; |
| // If building PIC object, a dynamic relocation with |
| // type RELATIVE is needed to relocate this GOT entry. |
| if (config().isCodeIndep()) |
| helper_GOT_init(pReloc, true, *this); |
| else |
| helper_GOT_init(pReloc, false, *this); |
| // set GOT bit |
| rsym->setReserved(rsym->reserved() | ReserveGOT); |
| return; |
| } |
| |
| default: |
| break; |
| } |
| } |
| |
| void AArch64Relocator::scanGlobalReloc(Relocation& pReloc, |
| IRBuilder& pBuilder, |
| const LDSection& pSection) { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| switch (pReloc.type()) { |
| case llvm::ELF::R_AARCH64_ABS64: |
| case llvm::ELF::R_AARCH64_ABS32: |
| case llvm::ELF::R_AARCH64_ABS16: |
| // Absolute relocation type, symbol may needs PLT entry or |
| // dynamic relocation entry |
| if (getTarget().symbolNeedsPLT(*rsym)) { |
| // create plt for this symbol if it does not have one |
| if (!(rsym->reserved() & ReservePLT)) { |
| // Symbol needs PLT entry, we need a PLT entry |
| // and the corresponding GOT and dynamic relocation entry |
| // in .got and .rel.plt. |
| helper_PLT_init(pReloc, *this); |
| // set PLT bit |
| rsym->setReserved(rsym->reserved() | ReservePLT); |
| } |
| } |
| |
| if (getTarget() |
| .symbolNeedsDynRel( |
| *rsym, (rsym->reserved() & ReservePLT), true)) { |
| // symbol needs dynamic relocation entry, set up the dynrel entry |
| if (getTarget().symbolNeedsCopyReloc(pReloc, *rsym)) { |
| LDSymbol& cpy_sym = defineSymbolforCopyReloc(pBuilder, *rsym); |
| addCopyReloc(*cpy_sym.resolveInfo()); |
| } else { |
| // set Rel bit and the dyn rel |
| rsym->setReserved(rsym->reserved() | ReserveRel); |
| getTarget().checkAndSetHasTextRel(*pSection.getLink()); |
| if (llvm::ELF::R_AARCH64_ABS64 == pReloc.type() && |
| helper_use_relative_reloc(*rsym, *this)) { |
| Relocation& reloc = |
| helper_DynRela_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| llvm::ELF::R_AARCH64_RELATIVE, |
| *this); |
| getRelRelMap().record(pReloc, reloc); |
| } else { |
| Relocation& reloc = helper_DynRela_init(rsym, |
| *pReloc.targetRef().frag(), |
| pReloc.targetRef().offset(), |
| pReloc.type(), |
| *this); |
| getRelRelMap().record(pReloc, reloc); |
| } |
| } |
| } |
| return; |
| |
| case llvm::ELF::R_AARCH64_PREL64: |
| case llvm::ELF::R_AARCH64_PREL32: |
| case llvm::ELF::R_AARCH64_PREL16: |
| if (getTarget().symbolNeedsPLT(*rsym) && |
| LinkerConfig::DynObj != config().codeGenType()) { |
| // create plt for this symbol if it does not have one |
| if (!(rsym->reserved() & ReservePLT)) { |
| // Symbol needs PLT entry, we need a PLT entry |
| // and the corresponding GOT and dynamic relocation entry |
| // in .got and .rel.plt. |
| helper_PLT_init(pReloc, *this); |
| // set PLT bit |
| rsym->setReserved(rsym->reserved() | ReservePLT); |
| } |
| } |
| |
| // Only PC relative relocation against dynamic symbol needs a |
| // dynamic relocation. Only dynamic copy relocation is allowed |
| // and PC relative relocation will be resolved to the local copy. |
| // All other dynamic relocations may lead to run-time relocation |
| // overflow. |
| if (getTarget().isDynamicSymbol(*rsym) && |
| getTarget() |
| .symbolNeedsDynRel( |
| *rsym, (rsym->reserved() & ReservePLT), false) && |
| getTarget().symbolNeedsCopyReloc(pReloc, *rsym)) { |
| LDSymbol& cpy_sym = defineSymbolforCopyReloc(pBuilder, *rsym); |
| addCopyReloc(*cpy_sym.resolveInfo()); |
| } |
| return; |
| |
| case llvm::ELF::R_AARCH64_CONDBR19: |
| case llvm::ELF::R_AARCH64_JUMP26: |
| case llvm::ELF::R_AARCH64_CALL26: { |
| // 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 (getTarget().symbolFinalValueIsKnown(*rsym)) |
| return; |
| |
| // if symbol is defined in the ouput file and it's not |
| // preemptible, no need plt |
| if (rsym->isDefine() && !rsym->isDyn() && |
| !getTarget().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. |
| helper_PLT_init(pReloc, *this); |
| // set PLT bit |
| rsym->setReserved(rsym->reserved() | ReservePLT); |
| return; |
| } |
| |
| case llvm::ELF::R_AARCH64_ADR_PREL_LO21: |
| case llvm::ELF::R_AARCH64_ADR_PREL_PG_HI21: |
| case llvm::ELF::R_AARCH64_ADR_PREL_PG_HI21_NC: |
| if (getTarget() |
| .symbolNeedsDynRel( |
| *rsym, (rsym->reserved() & ReservePLT), false)) { |
| if (getTarget().symbolNeedsCopyReloc(pReloc, *rsym)) { |
| LDSymbol& cpy_sym = defineSymbolforCopyReloc(pBuilder, *rsym); |
| addCopyReloc(*cpy_sym.resolveInfo()); |
| } |
| } |
| if (getTarget().symbolNeedsPLT(*rsym)) { |
| // create plt for this symbol if it does not have one |
| if (!(rsym->reserved() & ReservePLT)) { |
| // Symbol needs PLT entry, we need a PLT entry |
| // and the corresponding GOT and dynamic relocation entry |
| // in .got and .rel.plt. |
| helper_PLT_init(pReloc, *this); |
| // set PLT bit |
| rsym->setReserved(rsym->reserved() | ReservePLT); |
| } |
| } |
| return; |
| |
| case llvm::ELF::R_AARCH64_ADR_GOT_PAGE: |
| case llvm::ELF::R_AARCH64_LD64_GOT_LO12_NC: { |
| // Symbol needs GOT entry, reserve entry in .got |
| // return if we already create GOT for this symbol |
| if (rsym->reserved() & ReserveGOT) |
| return; |
| // if the symbol cannot be fully resolved at link time, then we need a |
| // dynamic relocation |
| if (!getTarget().symbolFinalValueIsKnown(*rsym)) |
| helper_GOT_init(pReloc, true, *this); |
| else |
| helper_GOT_init(pReloc, false, *this); |
| // set GOT bit |
| rsym->setReserved(rsym->reserved() | ReserveGOT); |
| return; |
| } |
| |
| default: |
| break; |
| } |
| } |
| |
| void AArch64Relocator::scanRelocation(Relocation& pReloc, |
| IRBuilder& pBuilder, |
| Module& pModule, |
| LDSection& pSection, |
| Input& pInput) { |
| ResolveInfo* rsym = pReloc.symInfo(); |
| assert(rsym != NULL && |
| "ResolveInfo of relocation not set while scanRelocation"); |
| |
| assert(pSection.getLink() != NULL); |
| if ((pSection.getLink()->flag() & llvm::ELF::SHF_ALLOC) == 0) |
| 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, pSection); |
| // rsym is external |
| else |
| scanGlobalReloc(pReloc, pBuilder, pSection); |
| |
| // check if we shoule issue undefined reference for the relocation target |
| // symbol |
| if (rsym->isUndef() && !rsym->isDyn() && !rsym->isWeak() && !rsym->isNull()) |
| issueUndefRef(pReloc, pSection, pInput); |
| } |
| |
| bool |
| AArch64Relocator::mayHaveFunctionPointerAccess(const Relocation& pReloc) const { |
| switch (pReloc.type()) { |
| case llvm::ELF::R_AARCH64_ADR_PREL_PG_HI21: |
| case llvm::ELF::R_AARCH64_ADR_PREL_PG_HI21_NC: |
| case llvm::ELF::R_AARCH64_ADD_ABS_LO12_NC: |
| case llvm::ELF::R_AARCH64_ADR_GOT_PAGE: |
| case llvm::ELF::R_AARCH64_LD64_GOT_LO12_NC: { |
| return true; |
| } |
| default: { |
| if (pReloc.symInfo()->isLocal()) { |
| // Do not fold any local symbols if building a shared object. |
| return (config().codeGenType() == LinkerConfig::DynObj); |
| } else { |
| // Do not fold any none global defualt symbols if building a shared |
| // object. |
| return ((config().codeGenType() == LinkerConfig::DynObj) && |
| (pReloc.symInfo()->visibility() != ResolveInfo::Default)); |
| } |
| } |
| } |
| return false; |
| } |
| |
| uint32_t AArch64Relocator::getDebugStringOffset(Relocation& pReloc) const { |
| if (pReloc.type() != llvm::ELF::R_AARCH64_ABS32) |
| error(diag::unsupport_reloc_for_debug_string) |
| << getName(pReloc.type()) << "mclinker@googlegroups.com"; |
| |
| if (pReloc.symInfo()->type() == ResolveInfo::Section) |
| return pReloc.target() + pReloc.addend(); |
| else |
| return pReloc.symInfo()->outSymbol()->fragRef()->offset() + |
| pReloc.target() + pReloc.addend(); |
| } |
| |
| void AArch64Relocator::applyDebugStringOffset(Relocation& pReloc, |
| uint32_t pOffset) { |
| pReloc.target() = pOffset; |
| } |
| |
| //===----------------------------------------------------------------------===// |
| // Each relocation function implementation |
| //===----------------------------------------------------------------------===// |
| |
| // R_AARCH64_NONE |
| Relocator::Result none(Relocation& pReloc, AArch64Relocator& pParent) { |
| return Relocator::OK; |
| } |
| |
| Relocator::Result unsupported(Relocation& pReloc, AArch64Relocator& pParent) { |
| return Relocator::Unsupported; |
| } |
| |
| // R_AARCH64_ABS64: S + A |
| // R_AARCH64_ABS32: S + A |
| // R_AARCH64_ABS16: S + A |
| Relocator::Result abs(Relocation& pReloc, AArch64Relocator& pParent) { |
| ResolveInfo* rsym = pReloc.symInfo(); |
| Relocator::DWord A = pReloc.target() + pReloc.addend(); |
| Relocator::DWord S = pReloc.symValue(); |
| Relocation* dyn_rel = pParent.getRelRelMap().lookUp(pReloc); |
| bool has_dyn_rel = (dyn_rel != NULL); |
| |
| LDSection& target_sect = pReloc.targetRef().frag()->getParent()->getSection(); |
| // If the flag of target section is not ALLOC, we will not scan this |
| // relocation but perform static relocation. (e.g., applying .debug section) |
| if (0x0 == (llvm::ELF::SHF_ALLOC & target_sect.flag())) { |
| pReloc.target() = S + A; |
| return Relocator::OK; |
| } |
| // A local symbol may need RELATIVE Type dynamic relocation |
| if (rsym->isLocal() && has_dyn_rel) { |
| dyn_rel->setAddend(S + A); |
| } |
| |
| // An external symbol may need PLT and dynamic relocation |
| if (!rsym->isLocal()) { |
| if (rsym->reserved() & AArch64Relocator::ReservePLT) { |
| S = helper_get_PLT_address(*rsym, pParent); |
| } |
| // If we generate a dynamic relocation (except R_AARCH64_64_RELATIVE) |
| // for a place, we should not perform static relocation on it |
| // in order to keep the addend store in the place correct. |
| if (has_dyn_rel) { |
| if (llvm::ELF::R_AARCH64_ABS64 == pReloc.type() && |
| llvm::ELF::R_AARCH64_RELATIVE == dyn_rel->type()) { |
| dyn_rel->setAddend(S + A); |
| } else { |
| dyn_rel->setAddend(A); |
| return Relocator::OK; |
| } |
| } |
| } |
| |
| // perform static relocation |
| pReloc.target() = S + A; |
| return Relocator::OK; |
| } |
| |
| // R_AARCH64_PREL64: S + A - P |
| // R_AARCH64_PREL32: S + A - P |
| // R_AARCH64_PREL16: S + A - P |
| Relocator::Result rel(Relocation& pReloc, AArch64Relocator& pParent) { |
| ResolveInfo* rsym = pReloc.symInfo(); |
| Relocator::Address S = pReloc.symValue(); |
| Relocator::DWord A = pReloc.addend(); |
| Relocator::DWord P = pReloc.place(); |
| |
| if (llvm::ELF::R_AARCH64_PREL64 != pReloc.type()) |
| A += pReloc.target() & get_mask(pParent.getSize(pReloc.type())); |
| else |
| A += pReloc.target(); |
| |
| LDSection& target_sect = pReloc.targetRef().frag()->getParent()->getSection(); |
| // If the flag of target section is not ALLOC, we will not scan this |
| // relocation but perform static relocation. (e.g., applying .debug section) |
| if (0x0 != (llvm::ELF::SHF_ALLOC & target_sect.flag())) { |
| // if plt entry exists, the S value is the plt entry address |
| if (!rsym->isLocal()) { |
| if (rsym->reserved() & AArch64Relocator::ReservePLT) { |
| S = helper_get_PLT_address(*rsym, pParent); |
| } |
| } |
| } |
| |
| Relocator::DWord X = S + A - P; |
| pReloc.target() = X; |
| |
| if (llvm::ELF::R_AARCH64_PREL64 != pReloc.type() && |
| helper_check_signed_overflow(X, pParent.getSize(pReloc.type()))) |
| return Relocator::Overflow; |
| return Relocator::OK; |
| } |
| |
| // R_AARCH64_ADD_ABS_LO12_NC: S + A |
| Relocator::Result add_abs_lo12(Relocation& pReloc, AArch64Relocator& pParent) { |
| Relocator::Address value = 0x0; |
| Relocator::Address S = pReloc.symValue(); |
| Relocator::DWord A = pReloc.addend(); |
| |
| value = helper_get_page_offset(S + A); |
| pReloc.target() = helper_reencode_add_imm(pReloc.target(), value); |
| |
| return Relocator::OK; |
| } |
| |
| // R_AARCH64_ADR_PREL_LO21: S + A - P |
| Relocator::Result adr_prel_lo21(Relocation& pReloc, AArch64Relocator& pParent) { |
| ResolveInfo* rsym = pReloc.symInfo(); |
| Relocator::Address S = pReloc.symValue(); |
| // if plt entry exists, the S value is the plt entry address |
| if (rsym->reserved() & AArch64Relocator::ReservePLT) { |
| S = helper_get_PLT_address(*rsym, pParent); |
| } |
| Relocator::DWord A = pReloc.addend(); |
| Relocator::DWord P = pReloc.place(); |
| Relocator::DWord X = S + A - P; |
| |
| pReloc.target() = helper_reencode_adr_imm(pReloc.target(), X); |
| |
| return Relocator::OK; |
| } |
| |
| // R_AARCH64_ADR_PREL_PG_HI21: ((PG(S + A) - PG(P)) >> 12) |
| // R_AARCH64_ADR_PREL_PG_HI21_NC: ((PG(S + A) - PG(P)) >> 12) |
| Relocator::Result adr_prel_pg_hi21(Relocation& pReloc, |
| AArch64Relocator& pParent) { |
| ResolveInfo* rsym = pReloc.symInfo(); |
| Relocator::Address S = pReloc.symValue(); |
| // if plt entry exists, the S value is the plt entry address |
| if (rsym->reserved() & AArch64Relocator::ReservePLT) { |
| S = helper_get_PLT_address(*rsym, pParent); |
| } |
| Relocator::DWord A = pReloc.addend(); |
| Relocator::DWord P = pReloc.place(); |
| Relocator::DWord X = |
| helper_get_page_address(S + A) - helper_get_page_address(P); |
| |
| pReloc.target() = helper_reencode_adr_imm(pReloc.target(), (X >> 12)); |
| |
| return Relocator::OK; |
| } |
| |
| // R_AARCH64_CALL26: S + A - P |
| // R_AARCH64_JUMP26: S + A - P |
| Relocator::Result call(Relocation& pReloc, AArch64Relocator& pParent) { |
| // If target is undefined weak symbol, we only need to jump to the |
| // next instruction unless it has PLT entry. Rewrite instruction |
| // to NOP. |
| if (pReloc.symInfo()->isWeak() && pReloc.symInfo()->isUndef() && |
| !pReloc.symInfo()->isDyn() && |
| !(pReloc.symInfo()->reserved() & AArch64Relocator::ReservePLT)) { |
| // change target to NOP |
| pReloc.target() = 0xd503201f; |
| return Relocator::OK; |
| } |
| |
| Relocator::Address S = pReloc.symValue(); |
| Relocator::DWord A = pReloc.addend(); |
| Relocator::Address P = pReloc.place(); |
| |
| // S depends on PLT exists or not |
| if (pReloc.symInfo()->reserved() & AArch64Relocator::ReservePLT) |
| S = helper_get_PLT_address(*pReloc.symInfo(), pParent); |
| |
| Relocator::DWord X = S + A - P; |
| // TODO: check overflow.. |
| |
| pReloc.target() = helper_reencode_branch_offset_26(pReloc.target(), X >> 2); |
| |
| return Relocator::OK; |
| } |
| |
| // R_AARCH64_CONDBR19: S + A - P |
| Relocator::Result condbr(Relocation& pReloc, AArch64Relocator& pParent) { |
| // If target is undefined weak symbol, we only need to jump to the |
| // next instruction unless it has PLT entry. Rewrite instruction |
| // to NOP. |
| if (pReloc.symInfo()->isWeak() && pReloc.symInfo()->isUndef() && |
| !pReloc.symInfo()->isDyn() && |
| !(pReloc.symInfo()->reserved() & AArch64Relocator::ReservePLT)) { |
| // change target to NOP |
| pReloc.target() = 0xd503201f; |
| return Relocator::OK; |
| } |
| |
| Relocator::Address S = pReloc.symValue(); |
| Relocator::DWord A = pReloc.addend(); |
| Relocator::Address P = pReloc.place(); |
| |
| // S depends on PLT exists or not |
| if (pReloc.symInfo()->reserved() & AArch64Relocator::ReservePLT) |
| S = helper_get_PLT_address(*pReloc.symInfo(), pParent); |
| |
| Relocator::DWord X = S + A - P; |
| // TODO: check overflow.. |
| |
| pReloc.target() = helper_reencode_cond_branch_ofs_19(pReloc.target(), X >> 2); |
| |
| return Relocator::OK; |
| } |
| |
| // R_AARCH64_ADR_GOT_PAGE: Page(G(GDAT(S+A))) - Page(P) |
| Relocator::Result adr_got_page(Relocation& pReloc, AArch64Relocator& pParent) { |
| if (!(pReloc.symInfo()->reserved() & AArch64Relocator::ReserveGOT)) { |
| return Relocator::BadReloc; |
| } |
| |
| Relocator::Address GOT_S = helper_get_GOT_address(*pReloc.symInfo(), pParent); |
| Relocator::DWord A = pReloc.addend(); |
| Relocator::Address P = pReloc.place(); |
| Relocator::DWord X = |
| helper_get_page_address(GOT_S + A) - helper_get_page_address(P); |
| |
| pReloc.target() = helper_reencode_adr_imm(pReloc.target(), (X >> 12)); |
| |
| // setup got entry value if needed |
| AArch64GOTEntry* got_entry = pParent.getSymGOTMap().lookUp(*pReloc.symInfo()); |
| if (got_entry != NULL && AArch64Relocator::SymVal == got_entry->getValue()) |
| got_entry->setValue(pReloc.symValue()); |
| // setup relocation addend if needed |
| Relocation* dyn_rela = pParent.getRelRelMap().lookUp(pReloc); |
| if ((dyn_rela != NULL) && (AArch64Relocator::SymVal == dyn_rela->addend())) { |
| dyn_rela->setAddend(pReloc.symValue()); |
| } |
| return Relocator::OK; |
| } |
| |
| // R_AARCH64_LD64_GOT_LO12_NC: G(GDAT(S+A)) |
| Relocator::Result ld64_got_lo12(Relocation& pReloc, AArch64Relocator& pParent) { |
| if (!(pReloc.symInfo()->reserved() & AArch64Relocator::ReserveGOT)) { |
| return Relocator::BadReloc; |
| } |
| |
| Relocator::Address GOT_S = helper_get_GOT_address(*pReloc.symInfo(), pParent); |
| Relocator::DWord A = pReloc.addend(); |
| Relocator::DWord X = helper_get_page_offset(GOT_S + A); |
| |
| pReloc.target() = helper_reencode_ldst_pos_imm(pReloc.target(), (X >> 3)); |
| |
| // setup got entry value if needed |
| AArch64GOTEntry* got_entry = pParent.getSymGOTMap().lookUp(*pReloc.symInfo()); |
| if (got_entry != NULL && AArch64Relocator::SymVal == got_entry->getValue()) |
| got_entry->setValue(pReloc.symValue()); |
| |
| // setup relocation addend if needed |
| Relocation* dyn_rela = pParent.getRelRelMap().lookUp(pReloc); |
| if ((dyn_rela != NULL) && (AArch64Relocator::SymVal == dyn_rela->addend())) { |
| dyn_rela->setAddend(pReloc.symValue()); |
| } |
| |
| return Relocator::OK; |
| } |
| |
| // R_AARCH64_LDST8_ABS_LO12_NC: S + A |
| // R_AARCH64_LDST16_ABS_LO12_NC: S + A |
| // R_AARCH64_LDST32_ABS_LO12_NC: S + A |
| // R_AARCH64_LDST64_ABS_LO12_NC: S + A |
| // R_AARCH64_LDST128_ABS_LO12_NC: S + A |
| Relocator::Result ldst_abs_lo12(Relocation& pReloc, AArch64Relocator& pParent) { |
| Relocator::Address S = pReloc.symValue(); |
| Relocator::DWord A = pReloc.addend(); |
| Relocator::DWord X = helper_get_page_offset(S + A); |
| |
| switch (pReloc.type()) { |
| case llvm::ELF::R_AARCH64_LDST8_ABS_LO12_NC: |
| pReloc.target() = helper_reencode_ldst_pos_imm(pReloc.target(), X); |
| break; |
| case llvm::ELF::R_AARCH64_LDST16_ABS_LO12_NC: |
| pReloc.target() = helper_reencode_ldst_pos_imm(pReloc.target(), (X >> 1)); |
| break; |
| case llvm::ELF::R_AARCH64_LDST32_ABS_LO12_NC: |
| pReloc.target() = helper_reencode_ldst_pos_imm(pReloc.target(), (X >> 2)); |
| break; |
| case llvm::ELF::R_AARCH64_LDST64_ABS_LO12_NC: |
| pReloc.target() = helper_reencode_ldst_pos_imm(pReloc.target(), (X >> 3)); |
| break; |
| case llvm::ELF::R_AARCH64_LDST128_ABS_LO12_NC: |
| pReloc.target() = helper_reencode_ldst_pos_imm(pReloc.target(), (X >> 4)); |
| break; |
| default: |
| break; |
| } |
| return Relocator::OK; |
| } |
| |
| } // namespace mcld |
