| //===- X86RelocationFactory.cpp -------------------------------------------===// |
| // |
| // The MCLinker Project |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include <llvm/ADT/Twine.h> |
| #include <llvm/Support/ErrorHandling.h> |
| #include <llvm/Support/DataTypes.h> |
| #include <llvm/Support/ELF.h> |
| #include <mcld/MC/MCLDInfo.h> |
| #include <mcld/LD/Layout.h> |
| |
| #include "X86RelocationFactory.h" |
| #include "X86RelocationFunctions.h" |
| |
| using namespace mcld; |
| |
| DECL_X86_APPLY_RELOC_FUNCS |
| |
| //===--------------------------------------------------------------------===// |
| // X86RelocationFactory |
| X86RelocationFactory::X86RelocationFactory(size_t pNum, |
| X86GNULDBackend& pParent) |
| : RelocationFactory(pNum), |
| m_Target(pParent) { |
| } |
| |
| X86RelocationFactory::~X86RelocationFactory() |
| { |
| } |
| |
| void X86RelocationFactory::applyRelocation(Relocation& pRelocation, |
| const MCLDInfo& pLDInfo) |
| { |
| Relocation::Type type = pRelocation.type(); |
| |
| /// the prototype of applying function |
| typedef Result (*ApplyFunctionType)(Relocation& pReloc, |
| const MCLDInfo& pLDInfo, |
| X86RelocationFactory& pParent); |
| |
| // the table entry of applying functions |
| struct ApplyFunctionTriple { |
| ApplyFunctionType func; |
| unsigned int type; |
| const char* name; |
| }; |
| |
| // declare the table of applying functions |
| static ApplyFunctionTriple apply_functions[] = { |
| DECL_X86_APPLY_RELOC_FUNC_PTRS |
| }; |
| |
| if (type >= sizeof (apply_functions) / sizeof (apply_functions[0]) ) { |
| llvm::report_fatal_error(llvm::Twine("Unknown relocation type ") + |
| llvm::Twine((int) type) + |
| llvm::Twine(" to symbol `") + |
| pRelocation.symInfo()->name() + |
| llvm::Twine("'.")); |
| return; |
| } |
| |
| // apply the relocation |
| Result result = apply_functions[type].func(pRelocation, pLDInfo, *this); |
| |
| // check result |
| if (Overflow == result) { |
| llvm::report_fatal_error(llvm::Twine("Applying relocation `") + |
| llvm::Twine(apply_functions[type].name) + |
| llvm::Twine("' causes overflow. on symbol: `") + |
| llvm::Twine(pRelocation.symInfo()->name()) + |
| llvm::Twine("'.")); |
| return; |
| } |
| |
| if (BadReloc == result) { |
| llvm::report_fatal_error(llvm::Twine("Applying relocation `") + |
| llvm::Twine(apply_functions[type].name) + |
| llvm::Twine("' encounters unexpected opcode. " |
| "on symbol: `") + |
| llvm::Twine(pRelocation.symInfo()->name()) + |
| llvm::Twine("'.")); |
| return; |
| } |
| } |
| |
| |
| |
| // non-member functions |
| |
| //=========================================// |
| // Relocation helper function // |
| //=========================================// |
| |
| // Check if symbol can use relocation R_386_RELATIVE |
| static bool |
| helper_use_relative_reloc(const ResolveInfo& pSym, |
| const MCLDInfo& pLDInfo, |
| const X86RelocationFactory& pFactory) |
| |
| { |
| // if symbol is dynamic or undefine or preemptible |
| if(pSym.isDyn() || |
| pSym.isUndef() || |
| pFactory.getTarget().isSymbolPreemptible(pSym, pLDInfo, pLDInfo.output())) |
| return false; |
| return true; |
| } |
| |
| static |
| GOTEntry& helper_get_GOT_and_init(Relocation& pReloc, |
| const MCLDInfo& pLDInfo, |
| X86RelocationFactory& pParent) |
| { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| X86GNULDBackend& ld_backend = pParent.getTarget(); |
| |
| bool exist; |
| GOTEntry& got_entry = *ld_backend.getGOT().getEntry(*rsym, exist); |
| if (!exist) { |
| // If we first get this GOT entry, we should initialize it. |
| if (rsym->reserved() & X86GNULDBackend::ReserveGOT) { |
| // No corresponding dynamic relocation, initialize to the symbol value. |
| got_entry.setContent(pReloc.symValue()); |
| } |
| else if (rsym->reserved() & X86GNULDBackend::GOTRel) { |
| // Initialize corresponding dynamic relocation. |
| Relocation& rel_entry = |
| *ld_backend.getRelDyn().getEntry(*rsym, true, exist); |
| assert(!exist && "GOT entry not exist, but DynRel entry exist!"); |
| if(helper_use_relative_reloc(*rsym, pLDInfo, pParent)) { |
| // Initialize got entry to target symbol address |
| got_entry.setContent(pReloc.symValue()); |
| rel_entry.setType(llvm::ELF::R_386_RELATIVE); |
| rel_entry.setSymInfo(0); |
| } |
| else { |
| got_entry.setContent(0); |
| rel_entry.setType(llvm::ELF::R_386_GLOB_DAT); |
| rel_entry.setSymInfo(rsym); |
| } |
| rel_entry.targetRef().assign(got_entry); |
| } |
| else { |
| llvm::report_fatal_error("No GOT entry reserved for GOT type relocation!"); |
| } |
| } |
| return got_entry; |
| } |
| |
| |
| static |
| X86RelocationFactory::Address helper_GOT_ORG(X86RelocationFactory& pParent) |
| { |
| return pParent.getTarget().getGOT().getSection().addr(); |
| } |
| |
| |
| static |
| X86RelocationFactory::Address helper_GOT(Relocation& pReloc, |
| const MCLDInfo& pLDInfo, |
| X86RelocationFactory& pParent) |
| { |
| GOTEntry& got_entry = helper_get_GOT_and_init(pReloc, pLDInfo, pParent); |
| return helper_GOT_ORG(pParent) + pParent.getLayout().getOutputOffset(got_entry); |
| } |
| |
| |
| static |
| PLTEntry& helper_get_PLT_and_init(Relocation& pReloc, |
| X86RelocationFactory& pParent) |
| { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| X86GNULDBackend& ld_backend = pParent.getTarget(); |
| |
| bool exist; |
| PLTEntry& plt_entry = *ld_backend.getPLT().getPLTEntry(*rsym, exist); |
| if (!exist) { |
| // If we first get this PLT entry, we should initialize it. |
| if (rsym->reserved() & X86GNULDBackend::ReservePLT) { |
| GOTEntry& gotplt_entry = |
| *ld_backend.getPLT().getGOTPLTEntry(*rsym, exist); |
| // Initialize corresponding dynamic relocation. |
| Relocation& rel_entry = |
| *ld_backend.getRelPLT().getEntry(*rsym, true, exist); |
| assert(!exist && "PLT entry not exist, but DynRel entry exist!"); |
| rel_entry.setType(llvm::ELF::R_386_JUMP_SLOT); |
| rel_entry.targetRef().assign(gotplt_entry); |
| rel_entry.setSymInfo(rsym); |
| } |
| else { |
| llvm::report_fatal_error("No PLT entry reserved for PLT type relocation!"); |
| } |
| } |
| return plt_entry; |
| } |
| |
| |
| |
| static |
| X86RelocationFactory::Address helper_PLT_ORG(X86RelocationFactory& pParent) |
| { |
| return pParent.getTarget().getPLT().getSection().addr(); |
| } |
| |
| |
| static |
| X86RelocationFactory::Address helper_PLT(Relocation& pReloc, |
| X86RelocationFactory& pParent) |
| { |
| PLTEntry& plt_entry = helper_get_PLT_and_init(pReloc, pParent); |
| return helper_PLT_ORG(pParent) + pParent.getLayout().getOutputOffset(plt_entry); |
| } |
| |
| // Get an relocation entry in .rel.dyn and set its type to pType, |
| // its FragmentRef to pReloc->targetFrag() and its ResolveInfo to pReloc->symInfo() |
| static |
| void helper_DynRel(Relocation& pReloc, |
| X86RelocationFactory::Type pType, |
| X86RelocationFactory& pParent) |
| { |
| // rsym - The relocation target symbol |
| ResolveInfo* rsym = pReloc.symInfo(); |
| X86GNULDBackend& ld_backend = pParent.getTarget(); |
| bool exist; |
| |
| Relocation& rel_entry = |
| *ld_backend.getRelDyn().getEntry(*rsym, false, exist); |
| rel_entry.setType(pType); |
| rel_entry.targetRef() = pReloc.targetRef(); |
| |
| if(pType == llvm::ELF::R_386_RELATIVE) |
| rel_entry.setSymInfo(0); |
| else |
| rel_entry.setSymInfo(rsym); |
| } |
| |
| |
| //=========================================// |
| // Each relocation function implementation // |
| //=========================================// |
| |
| // R_386_NONE |
| X86RelocationFactory::Result none(Relocation& pReloc, |
| const MCLDInfo& pLDInfo, |
| X86RelocationFactory& pParent) |
| { |
| return X86RelocationFactory::OK; |
| } |
| |
| // R_386_32: S + A |
| X86RelocationFactory::Result abs32(Relocation& pReloc, |
| const MCLDInfo& pLDInfo, |
| X86RelocationFactory& pParent) |
| { |
| ResolveInfo* rsym = pReloc.symInfo(); |
| RelocationFactory::DWord A = pReloc.target() + pReloc.addend(); |
| RelocationFactory::DWord S = pReloc.symValue(); |
| |
| if(rsym->isLocal() && (rsym->reserved() & X86GNULDBackend::ReserveRel)) { |
| helper_DynRel(pReloc, llvm::ELF::R_386_RELATIVE, pParent); |
| pReloc.target() = S + A; |
| return X86RelocationFactory::OK; |
| } |
| else if(!rsym->isLocal()) { |
| if(rsym->reserved() & X86GNULDBackend::ReservePLT) { |
| S = helper_PLT(pReloc, pParent); |
| pReloc.target() = S + A; |
| } |
| if(rsym->reserved() & X86GNULDBackend::ReserveRel) { |
| if(helper_use_relative_reloc(*rsym, pLDInfo, pParent) ) { |
| helper_DynRel(pReloc, llvm::ELF::R_386_RELATIVE, pParent); |
| } |
| else { |
| helper_DynRel(pReloc, pReloc.type(), pParent); |
| return X86RelocationFactory::OK; |
| } |
| } |
| } |
| |
| // perform static relocation |
| pReloc.target() = S + A; |
| return X86RelocationFactory::OK; |
| } |
| |
| // R_386_PC32: S + A - P |
| X86RelocationFactory::Result rel32(Relocation& pReloc, |
| const MCLDInfo& pLDInfo, |
| X86RelocationFactory& pParent) |
| { |
| // perform static relocation |
| RelocationFactory::DWord A = pReloc.target() + pReloc.addend(); |
| pReloc.target() = pReloc.symValue() + A |
| - pReloc.place(pParent.getLayout()); |
| return X86RelocationFactory::OK; |
| } |
| |
| // R_386_GOTOFF: S + A - GOT_ORG |
| X86RelocationFactory::Result gotoff32(Relocation& pReloc, |
| const MCLDInfo& pLDInfo, |
| X86RelocationFactory& pParent) |
| { |
| RelocationFactory::DWord A = pReloc.target() + pReloc.addend(); |
| X86RelocationFactory::Address GOT_ORG = helper_GOT_ORG(pParent); |
| X86RelocationFactory::Address S = pReloc.symValue(); |
| |
| pReloc.target() = S + A - GOT_ORG; |
| return X86RelocationFactory::OK; |
| } |
| |
| // R_386_GOTPC: GOT_ORG + A - P |
| X86RelocationFactory::Result gotpc32(Relocation& pReloc, |
| const MCLDInfo& pLDInfo, |
| X86RelocationFactory& pParent) |
| { |
| RelocationFactory::DWord A = pReloc.target() + pReloc.addend(); |
| X86RelocationFactory::Address GOT_ORG = helper_GOT_ORG(pParent); |
| // Apply relocation. |
| pReloc.target() = GOT_ORG + A - pReloc.place(pParent.getLayout()); |
| return X86RelocationFactory::OK; |
| } |
| |
| // R_386_GOT32: GOT(S) + A - GOT_ORG |
| X86RelocationFactory::Result got32(Relocation& pReloc, |
| const MCLDInfo& pLDInfo, |
| X86RelocationFactory& pParent) |
| { |
| if(!(pReloc.symInfo()->reserved() |
| & (X86GNULDBackend::ReserveGOT |X86GNULDBackend::GOTRel))) { |
| return X86RelocationFactory::BadReloc; |
| } |
| X86RelocationFactory::Address GOT_S = helper_GOT(pReloc, pLDInfo, pParent); |
| RelocationFactory::DWord A = pReloc.target() + pReloc.addend(); |
| X86RelocationFactory::Address GOT_ORG = helper_GOT_ORG(pParent); |
| // Apply relocation. |
| pReloc.target() = GOT_S + A - GOT_ORG; |
| return X86RelocationFactory::OK; |
| } |
| |
| // R_386_PLT32: PLT(S) + A - P |
| X86RelocationFactory::Result plt32(Relocation& pReloc, |
| const MCLDInfo& pLDInfo, |
| X86RelocationFactory& pParent) |
| { |
| // PLT_S depends on if there is a PLT entry. |
| X86RelocationFactory::Address PLT_S; |
| if((pReloc.symInfo()->reserved() & X86GNULDBackend::ReservePLT)) |
| PLT_S = helper_PLT(pReloc, pParent); |
| else |
| PLT_S = pReloc.symValue(); |
| RelocationFactory::DWord A = pReloc.target() + pReloc.addend(); |
| X86RelocationFactory::Address P = pReloc.place(pParent.getLayout()); |
| pReloc.target() = PLT_S + A - P; |
| return X86RelocationFactory::OK; |
| } |
