| //===-- RuntimeDyldELF.cpp - Run-time dynamic linker for MC-JIT -*- C++ -*-===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // Implementation of ELF support for the MC-JIT runtime dynamic linker. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #define DEBUG_TYPE "dyld" |
| #include "RuntimeDyldELF.h" |
| #include "JITRegistrar.h" |
| #include "ObjectImageCommon.h" |
| #include "llvm/ADT/IntervalMap.h" |
| #include "llvm/ADT/OwningPtr.h" |
| #include "llvm/ADT/STLExtras.h" |
| #include "llvm/ADT/StringRef.h" |
| #include "llvm/ADT/Triple.h" |
| #include "llvm/ExecutionEngine/ObjectBuffer.h" |
| #include "llvm/ExecutionEngine/ObjectImage.h" |
| #include "llvm/Object/ELFObjectFile.h" |
| #include "llvm/Object/ObjectFile.h" |
| #include "llvm/Support/ELF.h" |
| using namespace llvm; |
| using namespace llvm::object; |
| |
| namespace { |
| |
| static inline |
| error_code check(error_code Err) { |
| if (Err) { |
| report_fatal_error(Err.message()); |
| } |
| return Err; |
| } |
| |
| template<class ELFT> |
| class DyldELFObject |
| : public ELFObjectFile<ELFT> { |
| LLVM_ELF_IMPORT_TYPES_ELFT(ELFT) |
| |
| typedef Elf_Shdr_Impl<ELFT> Elf_Shdr; |
| typedef Elf_Sym_Impl<ELFT> Elf_Sym; |
| typedef |
| Elf_Rel_Impl<ELFT, false> Elf_Rel; |
| typedef |
| Elf_Rel_Impl<ELFT, true> Elf_Rela; |
| |
| typedef Elf_Ehdr_Impl<ELFT> Elf_Ehdr; |
| |
| typedef typename ELFDataTypeTypedefHelper< |
| ELFT>::value_type addr_type; |
| |
| public: |
| DyldELFObject(MemoryBuffer *Wrapper, error_code &ec); |
| |
| void updateSectionAddress(const SectionRef &Sec, uint64_t Addr); |
| void updateSymbolAddress(const SymbolRef &Sym, uint64_t Addr); |
| |
| // Methods for type inquiry through isa, cast and dyn_cast |
| static inline bool classof(const Binary *v) { |
| return (isa<ELFObjectFile<ELFT> >(v) |
| && classof(cast<ELFObjectFile |
| <ELFT> >(v))); |
| } |
| static inline bool classof( |
| const ELFObjectFile<ELFT> *v) { |
| return v->isDyldType(); |
| } |
| }; |
| |
| template<class ELFT> |
| class ELFObjectImage : public ObjectImageCommon { |
| protected: |
| DyldELFObject<ELFT> *DyldObj; |
| bool Registered; |
| |
| public: |
| ELFObjectImage(ObjectBuffer *Input, |
| DyldELFObject<ELFT> *Obj) |
| : ObjectImageCommon(Input, Obj), |
| DyldObj(Obj), |
| Registered(false) {} |
| |
| virtual ~ELFObjectImage() { |
| if (Registered) |
| deregisterWithDebugger(); |
| } |
| |
| // Subclasses can override these methods to update the image with loaded |
| // addresses for sections and common symbols |
| virtual void updateSectionAddress(const SectionRef &Sec, uint64_t Addr) |
| { |
| DyldObj->updateSectionAddress(Sec, Addr); |
| } |
| |
| virtual void updateSymbolAddress(const SymbolRef &Sym, uint64_t Addr) |
| { |
| DyldObj->updateSymbolAddress(Sym, Addr); |
| } |
| |
| virtual void registerWithDebugger() |
| { |
| JITRegistrar::getGDBRegistrar().registerObject(*Buffer); |
| Registered = true; |
| } |
| virtual void deregisterWithDebugger() |
| { |
| JITRegistrar::getGDBRegistrar().deregisterObject(*Buffer); |
| } |
| }; |
| |
| // The MemoryBuffer passed into this constructor is just a wrapper around the |
| // actual memory. Ultimately, the Binary parent class will take ownership of |
| // this MemoryBuffer object but not the underlying memory. |
| template<class ELFT> |
| DyldELFObject<ELFT>::DyldELFObject(MemoryBuffer *Wrapper, error_code &ec) |
| : ELFObjectFile<ELFT>(Wrapper, ec) { |
| this->isDyldELFObject = true; |
| } |
| |
| template<class ELFT> |
| void DyldELFObject<ELFT>::updateSectionAddress(const SectionRef &Sec, |
| uint64_t Addr) { |
| DataRefImpl ShdrRef = Sec.getRawDataRefImpl(); |
| Elf_Shdr *shdr = const_cast<Elf_Shdr*>( |
| reinterpret_cast<const Elf_Shdr *>(ShdrRef.p)); |
| |
| // This assumes the address passed in matches the target address bitness |
| // The template-based type cast handles everything else. |
| shdr->sh_addr = static_cast<addr_type>(Addr); |
| } |
| |
| template<class ELFT> |
| void DyldELFObject<ELFT>::updateSymbolAddress(const SymbolRef &SymRef, |
| uint64_t Addr) { |
| |
| Elf_Sym *sym = const_cast<Elf_Sym*>( |
| ELFObjectFile<ELFT>::getSymbol(SymRef.getRawDataRefImpl())); |
| |
| // This assumes the address passed in matches the target address bitness |
| // The template-based type cast handles everything else. |
| sym->st_value = static_cast<addr_type>(Addr); |
| } |
| |
| } // namespace |
| |
| namespace llvm { |
| |
| void RuntimeDyldELF::registerEHFrames() { |
| if (!MemMgr) |
| return; |
| for (int i = 0, e = UnregisteredEHFrameSections.size(); i != e; ++i) { |
| SID EHFrameSID = UnregisteredEHFrameSections[i]; |
| uint8_t *EHFrameAddr = Sections[EHFrameSID].Address; |
| uint64_t EHFrameLoadAddr = Sections[EHFrameSID].LoadAddress; |
| size_t EHFrameSize = Sections[EHFrameSID].Size; |
| MemMgr->registerEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize); |
| RegisteredEHFrameSections.push_back(EHFrameSID); |
| } |
| UnregisteredEHFrameSections.clear(); |
| } |
| |
| void RuntimeDyldELF::deregisterEHFrames() { |
| if (!MemMgr) |
| return; |
| for (int i = 0, e = RegisteredEHFrameSections.size(); i != e; ++i) { |
| SID EHFrameSID = RegisteredEHFrameSections[i]; |
| uint8_t *EHFrameAddr = Sections[EHFrameSID].Address; |
| uint64_t EHFrameLoadAddr = Sections[EHFrameSID].LoadAddress; |
| size_t EHFrameSize = Sections[EHFrameSID].Size; |
| MemMgr->deregisterEHFrames(EHFrameAddr, EHFrameLoadAddr, EHFrameSize); |
| } |
| RegisteredEHFrameSections.clear(); |
| } |
| |
| ObjectImage *RuntimeDyldELF::createObjectImage(ObjectBuffer *Buffer) { |
| if (Buffer->getBufferSize() < ELF::EI_NIDENT) |
| llvm_unreachable("Unexpected ELF object size"); |
| std::pair<unsigned char, unsigned char> Ident = std::make_pair( |
| (uint8_t)Buffer->getBufferStart()[ELF::EI_CLASS], |
| (uint8_t)Buffer->getBufferStart()[ELF::EI_DATA]); |
| error_code ec; |
| |
| if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2LSB) { |
| DyldELFObject<ELFType<support::little, 4, false> > *Obj = |
| new DyldELFObject<ELFType<support::little, 4, false> >( |
| Buffer->getMemBuffer(), ec); |
| return new ELFObjectImage<ELFType<support::little, 4, false> >(Buffer, Obj); |
| } |
| else if (Ident.first == ELF::ELFCLASS32 && Ident.second == ELF::ELFDATA2MSB) { |
| DyldELFObject<ELFType<support::big, 4, false> > *Obj = |
| new DyldELFObject<ELFType<support::big, 4, false> >( |
| Buffer->getMemBuffer(), ec); |
| return new ELFObjectImage<ELFType<support::big, 4, false> >(Buffer, Obj); |
| } |
| else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2MSB) { |
| DyldELFObject<ELFType<support::big, 8, true> > *Obj = |
| new DyldELFObject<ELFType<support::big, 8, true> >( |
| Buffer->getMemBuffer(), ec); |
| return new ELFObjectImage<ELFType<support::big, 8, true> >(Buffer, Obj); |
| } |
| else if (Ident.first == ELF::ELFCLASS64 && Ident.second == ELF::ELFDATA2LSB) { |
| DyldELFObject<ELFType<support::little, 8, true> > *Obj = |
| new DyldELFObject<ELFType<support::little, 8, true> >( |
| Buffer->getMemBuffer(), ec); |
| return new ELFObjectImage<ELFType<support::little, 8, true> >(Buffer, Obj); |
| } |
| else |
| llvm_unreachable("Unexpected ELF format"); |
| } |
| |
| RuntimeDyldELF::~RuntimeDyldELF() { |
| } |
| |
| void RuntimeDyldELF::resolveX86_64Relocation(const SectionEntry &Section, |
| uint64_t Offset, |
| uint64_t Value, |
| uint32_t Type, |
| int64_t Addend, |
| uint64_t SymOffset) { |
| switch (Type) { |
| default: |
| llvm_unreachable("Relocation type not implemented yet!"); |
| break; |
| case ELF::R_X86_64_64: { |
| uint64_t *Target = reinterpret_cast<uint64_t*>(Section.Address + Offset); |
| *Target = Value + Addend; |
| DEBUG(dbgs() << "Writing " << format("%p", (Value + Addend)) |
| << " at " << format("%p\n",Target)); |
| break; |
| } |
| case ELF::R_X86_64_32: |
| case ELF::R_X86_64_32S: { |
| Value += Addend; |
| assert((Type == ELF::R_X86_64_32 && (Value <= UINT32_MAX)) || |
| (Type == ELF::R_X86_64_32S && |
| ((int64_t)Value <= INT32_MAX && (int64_t)Value >= INT32_MIN))); |
| uint32_t TruncatedAddr = (Value & 0xFFFFFFFF); |
| uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset); |
| *Target = TruncatedAddr; |
| DEBUG(dbgs() << "Writing " << format("%p", TruncatedAddr) |
| << " at " << format("%p\n",Target)); |
| break; |
| } |
| case ELF::R_X86_64_GOTPCREL: { |
| // findGOTEntry returns the 'G + GOT' part of the relocation calculation |
| // based on the load/target address of the GOT (not the current/local addr). |
| uint64_t GOTAddr = findGOTEntry(Value, SymOffset); |
| uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset); |
| uint64_t FinalAddress = Section.LoadAddress + Offset; |
| // The processRelocationRef method combines the symbol offset and the addend |
| // and in most cases that's what we want. For this relocation type, we need |
| // the raw addend, so we subtract the symbol offset to get it. |
| int64_t RealOffset = GOTAddr + Addend - SymOffset - FinalAddress; |
| assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN); |
| int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); |
| *Target = TruncOffset; |
| break; |
| } |
| case ELF::R_X86_64_PC32: { |
| // Get the placeholder value from the generated object since |
| // a previous relocation attempt may have overwritten the loaded version |
| uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress |
| + Offset); |
| uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset); |
| uint64_t FinalAddress = Section.LoadAddress + Offset; |
| int64_t RealOffset = *Placeholder + Value + Addend - FinalAddress; |
| assert(RealOffset <= INT32_MAX && RealOffset >= INT32_MIN); |
| int32_t TruncOffset = (RealOffset & 0xFFFFFFFF); |
| *Target = TruncOffset; |
| break; |
| } |
| case ELF::R_X86_64_PC64: { |
| // Get the placeholder value from the generated object since |
| // a previous relocation attempt may have overwritten the loaded version |
| uint64_t *Placeholder = reinterpret_cast<uint64_t*>(Section.ObjAddress |
| + Offset); |
| uint64_t *Target = reinterpret_cast<uint64_t*>(Section.Address + Offset); |
| uint64_t FinalAddress = Section.LoadAddress + Offset; |
| *Target = *Placeholder + Value + Addend - FinalAddress; |
| break; |
| } |
| } |
| } |
| |
| void RuntimeDyldELF::resolveX86Relocation(const SectionEntry &Section, |
| uint64_t Offset, |
| uint32_t Value, |
| uint32_t Type, |
| int32_t Addend) { |
| switch (Type) { |
| case ELF::R_386_32: { |
| // Get the placeholder value from the generated object since |
| // a previous relocation attempt may have overwritten the loaded version |
| uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress |
| + Offset); |
| uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset); |
| *Target = *Placeholder + Value + Addend; |
| break; |
| } |
| case ELF::R_386_PC32: { |
| // Get the placeholder value from the generated object since |
| // a previous relocation attempt may have overwritten the loaded version |
| uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress |
| + Offset); |
| uint32_t *Target = reinterpret_cast<uint32_t*>(Section.Address + Offset); |
| uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF); |
| uint32_t RealOffset = *Placeholder + Value + Addend - FinalAddress; |
| *Target = RealOffset; |
| break; |
| } |
| default: |
| // There are other relocation types, but it appears these are the |
| // only ones currently used by the LLVM ELF object writer |
| llvm_unreachable("Relocation type not implemented yet!"); |
| break; |
| } |
| } |
| |
| void RuntimeDyldELF::resolveAArch64Relocation(const SectionEntry &Section, |
| uint64_t Offset, |
| uint64_t Value, |
| uint32_t Type, |
| int64_t Addend) { |
| uint32_t *TargetPtr = reinterpret_cast<uint32_t*>(Section.Address + Offset); |
| uint64_t FinalAddress = Section.LoadAddress + Offset; |
| |
| DEBUG(dbgs() << "resolveAArch64Relocation, LocalAddress: 0x" |
| << format("%llx", Section.Address + Offset) |
| << " FinalAddress: 0x" << format("%llx",FinalAddress) |
| << " Value: 0x" << format("%llx",Value) |
| << " Type: 0x" << format("%x",Type) |
| << " Addend: 0x" << format("%llx",Addend) |
| << "\n"); |
| |
| switch (Type) { |
| default: |
| llvm_unreachable("Relocation type not implemented yet!"); |
| break; |
| case ELF::R_AARCH64_ABS64: { |
| uint64_t *TargetPtr = reinterpret_cast<uint64_t*>(Section.Address + Offset); |
| *TargetPtr = Value + Addend; |
| break; |
| } |
| case ELF::R_AARCH64_PREL32: { |
| uint64_t Result = Value + Addend - FinalAddress; |
| assert(static_cast<int64_t>(Result) >= INT32_MIN && |
| static_cast<int64_t>(Result) <= UINT32_MAX); |
| *TargetPtr = static_cast<uint32_t>(Result & 0xffffffffU); |
| break; |
| } |
| case ELF::R_AARCH64_CALL26: // fallthrough |
| case ELF::R_AARCH64_JUMP26: { |
| // Operation: S+A-P. Set Call or B immediate value to bits fff_fffc of the |
| // calculation. |
| uint64_t BranchImm = Value + Addend - FinalAddress; |
| |
| // "Check that -2^27 <= result < 2^27". |
| assert(-(1LL << 27) <= static_cast<int64_t>(BranchImm) && |
| static_cast<int64_t>(BranchImm) < (1LL << 27)); |
| |
| // AArch64 code is emitted with .rela relocations. The data already in any |
| // bits affected by the relocation on entry is garbage. |
| *TargetPtr &= 0xfc000000U; |
| // Immediate goes in bits 25:0 of B and BL. |
| *TargetPtr |= static_cast<uint32_t>(BranchImm & 0xffffffcU) >> 2; |
| break; |
| } |
| case ELF::R_AARCH64_MOVW_UABS_G3: { |
| uint64_t Result = Value + Addend; |
| |
| // AArch64 code is emitted with .rela relocations. The data already in any |
| // bits affected by the relocation on entry is garbage. |
| *TargetPtr &= 0xffe0001fU; |
| // Immediate goes in bits 20:5 of MOVZ/MOVK instruction |
| *TargetPtr |= Result >> (48 - 5); |
| // Shift must be "lsl #48", in bits 22:21 |
| assert((*TargetPtr >> 21 & 0x3) == 3 && "invalid shift for relocation"); |
| break; |
| } |
| case ELF::R_AARCH64_MOVW_UABS_G2_NC: { |
| uint64_t Result = Value + Addend; |
| |
| // AArch64 code is emitted with .rela relocations. The data already in any |
| // bits affected by the relocation on entry is garbage. |
| *TargetPtr &= 0xffe0001fU; |
| // Immediate goes in bits 20:5 of MOVZ/MOVK instruction |
| *TargetPtr |= ((Result & 0xffff00000000ULL) >> (32 - 5)); |
| // Shift must be "lsl #32", in bits 22:21 |
| assert((*TargetPtr >> 21 & 0x3) == 2 && "invalid shift for relocation"); |
| break; |
| } |
| case ELF::R_AARCH64_MOVW_UABS_G1_NC: { |
| uint64_t Result = Value + Addend; |
| |
| // AArch64 code is emitted with .rela relocations. The data already in any |
| // bits affected by the relocation on entry is garbage. |
| *TargetPtr &= 0xffe0001fU; |
| // Immediate goes in bits 20:5 of MOVZ/MOVK instruction |
| *TargetPtr |= ((Result & 0xffff0000U) >> (16 - 5)); |
| // Shift must be "lsl #16", in bits 22:2 |
| assert((*TargetPtr >> 21 & 0x3) == 1 && "invalid shift for relocation"); |
| break; |
| } |
| case ELF::R_AARCH64_MOVW_UABS_G0_NC: { |
| uint64_t Result = Value + Addend; |
| |
| // AArch64 code is emitted with .rela relocations. The data already in any |
| // bits affected by the relocation on entry is garbage. |
| *TargetPtr &= 0xffe0001fU; |
| // Immediate goes in bits 20:5 of MOVZ/MOVK instruction |
| *TargetPtr |= ((Result & 0xffffU) << 5); |
| // Shift must be "lsl #0", in bits 22:21. |
| assert((*TargetPtr >> 21 & 0x3) == 0 && "invalid shift for relocation"); |
| break; |
| } |
| } |
| } |
| |
| void RuntimeDyldELF::resolveARMRelocation(const SectionEntry &Section, |
| uint64_t Offset, |
| uint32_t Value, |
| uint32_t Type, |
| int32_t Addend) { |
| // TODO: Add Thumb relocations. |
| uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress + |
| Offset); |
| uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset); |
| uint32_t FinalAddress = ((Section.LoadAddress + Offset) & 0xFFFFFFFF); |
| Value += Addend; |
| |
| DEBUG(dbgs() << "resolveARMRelocation, LocalAddress: " |
| << Section.Address + Offset |
| << " FinalAddress: " << format("%p",FinalAddress) |
| << " Value: " << format("%x",Value) |
| << " Type: " << format("%x",Type) |
| << " Addend: " << format("%x",Addend) |
| << "\n"); |
| |
| switch(Type) { |
| default: |
| llvm_unreachable("Not implemented relocation type!"); |
| |
| // Write a 32bit value to relocation address, taking into account the |
| // implicit addend encoded in the target. |
| case ELF::R_ARM_TARGET1: |
| case ELF::R_ARM_ABS32: |
| *TargetPtr = *Placeholder + Value; |
| break; |
| // Write first 16 bit of 32 bit value to the mov instruction. |
| // Last 4 bit should be shifted. |
| case ELF::R_ARM_MOVW_ABS_NC: |
| // We are not expecting any other addend in the relocation address. |
| // Using 0x000F0FFF because MOVW has its 16 bit immediate split into 2 |
| // non-contiguous fields. |
| assert((*Placeholder & 0x000F0FFF) == 0); |
| Value = Value & 0xFFFF; |
| *TargetPtr = *Placeholder | (Value & 0xFFF); |
| *TargetPtr |= ((Value >> 12) & 0xF) << 16; |
| break; |
| // Write last 16 bit of 32 bit value to the mov instruction. |
| // Last 4 bit should be shifted. |
| case ELF::R_ARM_MOVT_ABS: |
| // We are not expecting any other addend in the relocation address. |
| // Use 0x000F0FFF for the same reason as R_ARM_MOVW_ABS_NC. |
| assert((*Placeholder & 0x000F0FFF) == 0); |
| |
| Value = (Value >> 16) & 0xFFFF; |
| *TargetPtr = *Placeholder | (Value & 0xFFF); |
| *TargetPtr |= ((Value >> 12) & 0xF) << 16; |
| break; |
| // Write 24 bit relative value to the branch instruction. |
| case ELF::R_ARM_PC24 : // Fall through. |
| case ELF::R_ARM_CALL : // Fall through. |
| case ELF::R_ARM_JUMP24: { |
| int32_t RelValue = static_cast<int32_t>(Value - FinalAddress - 8); |
| RelValue = (RelValue & 0x03FFFFFC) >> 2; |
| assert((*TargetPtr & 0xFFFFFF) == 0xFFFFFE); |
| *TargetPtr &= 0xFF000000; |
| *TargetPtr |= RelValue; |
| break; |
| } |
| case ELF::R_ARM_PRIVATE_0: |
| // This relocation is reserved by the ARM ELF ABI for internal use. We |
| // appropriate it here to act as an R_ARM_ABS32 without any addend for use |
| // in the stubs created during JIT (which can't put an addend into the |
| // original object file). |
| *TargetPtr = Value; |
| break; |
| } |
| } |
| |
| void RuntimeDyldELF::resolveMIPSRelocation(const SectionEntry &Section, |
| uint64_t Offset, |
| uint32_t Value, |
| uint32_t Type, |
| int32_t Addend) { |
| uint32_t *Placeholder = reinterpret_cast<uint32_t*>(Section.ObjAddress + |
| Offset); |
| uint32_t* TargetPtr = (uint32_t*)(Section.Address + Offset); |
| Value += Addend; |
| |
| DEBUG(dbgs() << "resolveMipselocation, LocalAddress: " |
| << Section.Address + Offset |
| << " FinalAddress: " |
| << format("%p",Section.LoadAddress + Offset) |
| << " Value: " << format("%x",Value) |
| << " Type: " << format("%x",Type) |
| << " Addend: " << format("%x",Addend) |
| << "\n"); |
| |
| switch(Type) { |
| default: |
| llvm_unreachable("Not implemented relocation type!"); |
| break; |
| case ELF::R_MIPS_32: |
| *TargetPtr = Value + (*Placeholder); |
| break; |
| case ELF::R_MIPS_26: |
| *TargetPtr = ((*Placeholder) & 0xfc000000) | (( Value & 0x0fffffff) >> 2); |
| break; |
| case ELF::R_MIPS_HI16: |
| // Get the higher 16-bits. Also add 1 if bit 15 is 1. |
| Value += ((*Placeholder) & 0x0000ffff) << 16; |
| *TargetPtr = ((*Placeholder) & 0xffff0000) | |
| (((Value + 0x8000) >> 16) & 0xffff); |
| break; |
| case ELF::R_MIPS_LO16: |
| Value += ((*Placeholder) & 0x0000ffff); |
| *TargetPtr = ((*Placeholder) & 0xffff0000) | (Value & 0xffff); |
| break; |
| case ELF::R_MIPS_UNUSED1: |
| // Similar to ELF::R_ARM_PRIVATE_0, R_MIPS_UNUSED1 and R_MIPS_UNUSED2 |
| // are used for internal JIT purpose. These relocations are similar to |
| // R_MIPS_HI16 and R_MIPS_LO16, but they do not take any addend into |
| // account. |
| *TargetPtr = ((*TargetPtr) & 0xffff0000) | |
| (((Value + 0x8000) >> 16) & 0xffff); |
| break; |
| case ELF::R_MIPS_UNUSED2: |
| *TargetPtr = ((*TargetPtr) & 0xffff0000) | (Value & 0xffff); |
| break; |
| } |
| } |
| |
| // Return the .TOC. section address to R_PPC64_TOC relocations. |
| uint64_t RuntimeDyldELF::findPPC64TOC() const { |
| // The TOC consists of sections .got, .toc, .tocbss, .plt in that |
| // order. The TOC starts where the first of these sections starts. |
| SectionList::const_iterator it = Sections.begin(); |
| SectionList::const_iterator ite = Sections.end(); |
| for (; it != ite; ++it) { |
| if (it->Name == ".got" || |
| it->Name == ".toc" || |
| it->Name == ".tocbss" || |
| it->Name == ".plt") |
| break; |
| } |
| if (it == ite) { |
| // This may happen for |
| // * references to TOC base base (sym@toc, .odp relocation) without |
| // a .toc directive. |
| // In this case just use the first section (which is usually |
| // the .odp) since the code won't reference the .toc base |
| // directly. |
| it = Sections.begin(); |
| } |
| assert (it != ite); |
| // Per the ppc64-elf-linux ABI, The TOC base is TOC value plus 0x8000 |
| // thus permitting a full 64 Kbytes segment. |
| return it->LoadAddress + 0x8000; |
| } |
| |
| // Returns the sections and offset associated with the ODP entry referenced |
| // by Symbol. |
| void RuntimeDyldELF::findOPDEntrySection(ObjectImage &Obj, |
| ObjSectionToIDMap &LocalSections, |
| RelocationValueRef &Rel) { |
| // Get the ELF symbol value (st_value) to compare with Relocation offset in |
| // .opd entries |
| |
| error_code err; |
| for (section_iterator si = Obj.begin_sections(), |
| se = Obj.end_sections(); si != se; si.increment(err)) { |
| section_iterator RelSecI = si->getRelocatedSection(); |
| if (RelSecI == Obj.end_sections()) |
| continue; |
| |
| StringRef RelSectionName; |
| check(RelSecI->getName(RelSectionName)); |
| if (RelSectionName != ".opd") |
| continue; |
| |
| for (relocation_iterator i = si->begin_relocations(), |
| e = si->end_relocations(); i != e;) { |
| check(err); |
| |
| // The R_PPC64_ADDR64 relocation indicates the first field |
| // of a .opd entry |
| uint64_t TypeFunc; |
| check(i->getType(TypeFunc)); |
| if (TypeFunc != ELF::R_PPC64_ADDR64) { |
| i.increment(err); |
| continue; |
| } |
| |
| uint64_t TargetSymbolOffset; |
| symbol_iterator TargetSymbol = i->getSymbol(); |
| check(i->getOffset(TargetSymbolOffset)); |
| int64_t Addend; |
| check(getELFRelocationAddend(*i, Addend)); |
| |
| i = i.increment(err); |
| if (i == e) |
| break; |
| check(err); |
| |
| // Just check if following relocation is a R_PPC64_TOC |
| uint64_t TypeTOC; |
| check(i->getType(TypeTOC)); |
| if (TypeTOC != ELF::R_PPC64_TOC) |
| continue; |
| |
| // Finally compares the Symbol value and the target symbol offset |
| // to check if this .opd entry refers to the symbol the relocation |
| // points to. |
| if (Rel.Addend != (int64_t)TargetSymbolOffset) |
| continue; |
| |
| section_iterator tsi(Obj.end_sections()); |
| check(TargetSymbol->getSection(tsi)); |
| Rel.SectionID = findOrEmitSection(Obj, (*tsi), true, LocalSections); |
| Rel.Addend = (intptr_t)Addend; |
| return; |
| } |
| } |
| llvm_unreachable("Attempting to get address of ODP entry!"); |
| } |
| |
| // Relocation masks following the #lo(value), #hi(value), #higher(value), |
| // and #highest(value) macros defined in section 4.5.1. Relocation Types |
| // in PPC-elf64abi document. |
| // |
| static inline |
| uint16_t applyPPClo (uint64_t value) |
| { |
| return value & 0xffff; |
| } |
| |
| static inline |
| uint16_t applyPPChi (uint64_t value) |
| { |
| return (value >> 16) & 0xffff; |
| } |
| |
| static inline |
| uint16_t applyPPChigher (uint64_t value) |
| { |
| return (value >> 32) & 0xffff; |
| } |
| |
| static inline |
| uint16_t applyPPChighest (uint64_t value) |
| { |
| return (value >> 48) & 0xffff; |
| } |
| |
| void RuntimeDyldELF::resolvePPC64Relocation(const SectionEntry &Section, |
| uint64_t Offset, |
| uint64_t Value, |
| uint32_t Type, |
| int64_t Addend) { |
| uint8_t* LocalAddress = Section.Address + Offset; |
| switch (Type) { |
| default: |
| llvm_unreachable("Relocation type not implemented yet!"); |
| break; |
| case ELF::R_PPC64_ADDR16_LO : |
| writeInt16BE(LocalAddress, applyPPClo (Value + Addend)); |
| break; |
| case ELF::R_PPC64_ADDR16_HI : |
| writeInt16BE(LocalAddress, applyPPChi (Value + Addend)); |
| break; |
| case ELF::R_PPC64_ADDR16_HIGHER : |
| writeInt16BE(LocalAddress, applyPPChigher (Value + Addend)); |
| break; |
| case ELF::R_PPC64_ADDR16_HIGHEST : |
| writeInt16BE(LocalAddress, applyPPChighest (Value + Addend)); |
| break; |
| case ELF::R_PPC64_ADDR14 : { |
| assert(((Value + Addend) & 3) == 0); |
| // Preserve the AA/LK bits in the branch instruction |
| uint8_t aalk = *(LocalAddress+3); |
| writeInt16BE(LocalAddress + 2, (aalk & 3) | ((Value + Addend) & 0xfffc)); |
| } break; |
| case ELF::R_PPC64_ADDR32 : { |
| int32_t Result = static_cast<int32_t>(Value + Addend); |
| if (SignExtend32<32>(Result) != Result) |
| llvm_unreachable("Relocation R_PPC64_ADDR32 overflow"); |
| writeInt32BE(LocalAddress, Result); |
| } break; |
| case ELF::R_PPC64_REL24 : { |
| uint64_t FinalAddress = (Section.LoadAddress + Offset); |
| int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend); |
| if (SignExtend32<24>(delta) != delta) |
| llvm_unreachable("Relocation R_PPC64_REL24 overflow"); |
| // Generates a 'bl <address>' instruction |
| writeInt32BE(LocalAddress, 0x48000001 | (delta & 0x03FFFFFC)); |
| } break; |
| case ELF::R_PPC64_REL32 : { |
| uint64_t FinalAddress = (Section.LoadAddress + Offset); |
| int32_t delta = static_cast<int32_t>(Value - FinalAddress + Addend); |
| if (SignExtend32<32>(delta) != delta) |
| llvm_unreachable("Relocation R_PPC64_REL32 overflow"); |
| writeInt32BE(LocalAddress, delta); |
| } break; |
| case ELF::R_PPC64_REL64: { |
| uint64_t FinalAddress = (Section.LoadAddress + Offset); |
| uint64_t Delta = Value - FinalAddress + Addend; |
| writeInt64BE(LocalAddress, Delta); |
| } break; |
| case ELF::R_PPC64_ADDR64 : |
| writeInt64BE(LocalAddress, Value + Addend); |
| break; |
| case ELF::R_PPC64_TOC : |
| writeInt64BE(LocalAddress, findPPC64TOC()); |
| break; |
| case ELF::R_PPC64_TOC16 : { |
| uint64_t TOCStart = findPPC64TOC(); |
| Value = applyPPClo((Value + Addend) - TOCStart); |
| writeInt16BE(LocalAddress, applyPPClo(Value)); |
| } break; |
| case ELF::R_PPC64_TOC16_DS : { |
| uint64_t TOCStart = findPPC64TOC(); |
| Value = ((Value + Addend) - TOCStart); |
| writeInt16BE(LocalAddress, applyPPClo(Value)); |
| } break; |
| } |
| } |
| |
| void RuntimeDyldELF::resolveSystemZRelocation(const SectionEntry &Section, |
| uint64_t Offset, |
| uint64_t Value, |
| uint32_t Type, |
| int64_t Addend) { |
| uint8_t *LocalAddress = Section.Address + Offset; |
| switch (Type) { |
| default: |
| llvm_unreachable("Relocation type not implemented yet!"); |
| break; |
| case ELF::R_390_PC16DBL: |
| case ELF::R_390_PLT16DBL: { |
| int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset); |
| assert(int16_t(Delta / 2) * 2 == Delta && "R_390_PC16DBL overflow"); |
| writeInt16BE(LocalAddress, Delta / 2); |
| break; |
| } |
| case ELF::R_390_PC32DBL: |
| case ELF::R_390_PLT32DBL: { |
| int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset); |
| assert(int32_t(Delta / 2) * 2 == Delta && "R_390_PC32DBL overflow"); |
| writeInt32BE(LocalAddress, Delta / 2); |
| break; |
| } |
| case ELF::R_390_PC32: { |
| int64_t Delta = (Value + Addend) - (Section.LoadAddress + Offset); |
| assert(int32_t(Delta) == Delta && "R_390_PC32 overflow"); |
| writeInt32BE(LocalAddress, Delta); |
| break; |
| } |
| case ELF::R_390_64: |
| writeInt64BE(LocalAddress, Value + Addend); |
| break; |
| } |
| } |
| |
| // The target location for the relocation is described by RE.SectionID and |
| // RE.Offset. RE.SectionID can be used to find the SectionEntry. Each |
| // SectionEntry has three members describing its location. |
| // SectionEntry::Address is the address at which the section has been loaded |
| // into memory in the current (host) process. SectionEntry::LoadAddress is the |
| // address that the section will have in the target process. |
| // SectionEntry::ObjAddress is the address of the bits for this section in the |
| // original emitted object image (also in the current address space). |
| // |
| // Relocations will be applied as if the section were loaded at |
| // SectionEntry::LoadAddress, but they will be applied at an address based |
| // on SectionEntry::Address. SectionEntry::ObjAddress will be used to refer to |
| // Target memory contents if they are required for value calculations. |
| // |
| // The Value parameter here is the load address of the symbol for the |
| // relocation to be applied. For relocations which refer to symbols in the |
| // current object Value will be the LoadAddress of the section in which |
| // the symbol resides (RE.Addend provides additional information about the |
| // symbol location). For external symbols, Value will be the address of the |
| // symbol in the target address space. |
| void RuntimeDyldELF::resolveRelocation(const RelocationEntry &RE, |
| uint64_t Value) { |
| const SectionEntry &Section = Sections[RE.SectionID]; |
| return resolveRelocation(Section, RE.Offset, Value, RE.RelType, RE.Addend, |
| RE.SymOffset); |
| } |
| |
| void RuntimeDyldELF::resolveRelocation(const SectionEntry &Section, |
| uint64_t Offset, |
| uint64_t Value, |
| uint32_t Type, |
| int64_t Addend, |
| uint64_t SymOffset) { |
| switch (Arch) { |
| case Triple::x86_64: |
| resolveX86_64Relocation(Section, Offset, Value, Type, Addend, SymOffset); |
| break; |
| case Triple::x86: |
| resolveX86Relocation(Section, Offset, |
| (uint32_t)(Value & 0xffffffffL), Type, |
| (uint32_t)(Addend & 0xffffffffL)); |
| break; |
| case Triple::aarch64: |
| resolveAArch64Relocation(Section, Offset, Value, Type, Addend); |
| break; |
| case Triple::arm: // Fall through. |
| case Triple::thumb: |
| resolveARMRelocation(Section, Offset, |
| (uint32_t)(Value & 0xffffffffL), Type, |
| (uint32_t)(Addend & 0xffffffffL)); |
| break; |
| case Triple::mips: // Fall through. |
| case Triple::mipsel: |
| resolveMIPSRelocation(Section, Offset, |
| (uint32_t)(Value & 0xffffffffL), Type, |
| (uint32_t)(Addend & 0xffffffffL)); |
| break; |
| case Triple::ppc64: // Fall through. |
| case Triple::ppc64le: |
| resolvePPC64Relocation(Section, Offset, Value, Type, Addend); |
| break; |
| case Triple::systemz: |
| resolveSystemZRelocation(Section, Offset, Value, Type, Addend); |
| break; |
| default: llvm_unreachable("Unsupported CPU type!"); |
| } |
| } |
| |
| void RuntimeDyldELF::processRelocationRef(unsigned SectionID, |
| RelocationRef RelI, |
| ObjectImage &Obj, |
| ObjSectionToIDMap &ObjSectionToID, |
| const SymbolTableMap &Symbols, |
| StubMap &Stubs) { |
| uint64_t RelType; |
| Check(RelI.getType(RelType)); |
| int64_t Addend; |
| Check(getELFRelocationAddend(RelI, Addend)); |
| symbol_iterator Symbol = RelI.getSymbol(); |
| |
| // Obtain the symbol name which is referenced in the relocation |
| StringRef TargetName; |
| if (Symbol != Obj.end_symbols()) |
| Symbol->getName(TargetName); |
| DEBUG(dbgs() << "\t\tRelType: " << RelType |
| << " Addend: " << Addend |
| << " TargetName: " << TargetName |
| << "\n"); |
| RelocationValueRef Value; |
| // First search for the symbol in the local symbol table |
| SymbolTableMap::const_iterator lsi = Symbols.end(); |
| SymbolRef::Type SymType = SymbolRef::ST_Unknown; |
| if (Symbol != Obj.end_symbols()) { |
| lsi = Symbols.find(TargetName.data()); |
| Symbol->getType(SymType); |
| } |
| if (lsi != Symbols.end()) { |
| Value.SectionID = lsi->second.first; |
| Value.Offset = lsi->second.second; |
| Value.Addend = lsi->second.second + Addend; |
| } else { |
| // Search for the symbol in the global symbol table |
| SymbolTableMap::const_iterator gsi = GlobalSymbolTable.end(); |
| if (Symbol != Obj.end_symbols()) |
| gsi = GlobalSymbolTable.find(TargetName.data()); |
| if (gsi != GlobalSymbolTable.end()) { |
| Value.SectionID = gsi->second.first; |
| Value.Offset = gsi->second.second; |
| Value.Addend = gsi->second.second + Addend; |
| } else { |
| switch (SymType) { |
| case SymbolRef::ST_Debug: { |
| // TODO: Now ELF SymbolRef::ST_Debug = STT_SECTION, it's not obviously |
| // and can be changed by another developers. Maybe best way is add |
| // a new symbol type ST_Section to SymbolRef and use it. |
| section_iterator si(Obj.end_sections()); |
| Symbol->getSection(si); |
| if (si == Obj.end_sections()) |
| llvm_unreachable("Symbol section not found, bad object file format!"); |
| DEBUG(dbgs() << "\t\tThis is section symbol\n"); |
| // Default to 'true' in case isText fails (though it never does). |
| bool isCode = true; |
| si->isText(isCode); |
| Value.SectionID = findOrEmitSection(Obj, |
| (*si), |
| isCode, |
| ObjSectionToID); |
| Value.Addend = Addend; |
| break; |
| } |
| case SymbolRef::ST_Data: |
| case SymbolRef::ST_Unknown: { |
| Value.SymbolName = TargetName.data(); |
| Value.Addend = Addend; |
| |
| // Absolute relocations will have a zero symbol ID (STN_UNDEF), which |
| // will manifest here as a NULL symbol name. |
| // We can set this as a valid (but empty) symbol name, and rely |
| // on addRelocationForSymbol to handle this. |
| if (!Value.SymbolName) |
| Value.SymbolName = ""; |
| break; |
| } |
| default: |
| llvm_unreachable("Unresolved symbol type!"); |
| break; |
| } |
| } |
| } |
| uint64_t Offset; |
| Check(RelI.getOffset(Offset)); |
| |
| DEBUG(dbgs() << "\t\tSectionID: " << SectionID |
| << " Offset: " << Offset |
| << "\n"); |
| if (Arch == Triple::aarch64 && |
| (RelType == ELF::R_AARCH64_CALL26 || |
| RelType == ELF::R_AARCH64_JUMP26)) { |
| // This is an AArch64 branch relocation, need to use a stub function. |
| DEBUG(dbgs() << "\t\tThis is an AArch64 branch relocation."); |
| SectionEntry &Section = Sections[SectionID]; |
| |
| // Look for an existing stub. |
| StubMap::const_iterator i = Stubs.find(Value); |
| if (i != Stubs.end()) { |
| resolveRelocation(Section, Offset, |
| (uint64_t)Section.Address + i->second, RelType, 0); |
| DEBUG(dbgs() << " Stub function found\n"); |
| } else { |
| // Create a new stub function. |
| DEBUG(dbgs() << " Create a new stub function\n"); |
| Stubs[Value] = Section.StubOffset; |
| uint8_t *StubTargetAddr = createStubFunction(Section.Address + |
| Section.StubOffset); |
| |
| RelocationEntry REmovz_g3(SectionID, |
| StubTargetAddr - Section.Address, |
| ELF::R_AARCH64_MOVW_UABS_G3, Value.Addend); |
| RelocationEntry REmovk_g2(SectionID, |
| StubTargetAddr - Section.Address + 4, |
| ELF::R_AARCH64_MOVW_UABS_G2_NC, Value.Addend); |
| RelocationEntry REmovk_g1(SectionID, |
| StubTargetAddr - Section.Address + 8, |
| ELF::R_AARCH64_MOVW_UABS_G1_NC, Value.Addend); |
| RelocationEntry REmovk_g0(SectionID, |
| StubTargetAddr - Section.Address + 12, |
| ELF::R_AARCH64_MOVW_UABS_G0_NC, Value.Addend); |
| |
| if (Value.SymbolName) { |
| addRelocationForSymbol(REmovz_g3, Value.SymbolName); |
| addRelocationForSymbol(REmovk_g2, Value.SymbolName); |
| addRelocationForSymbol(REmovk_g1, Value.SymbolName); |
| addRelocationForSymbol(REmovk_g0, Value.SymbolName); |
| } else { |
| addRelocationForSection(REmovz_g3, Value.SectionID); |
| addRelocationForSection(REmovk_g2, Value.SectionID); |
| addRelocationForSection(REmovk_g1, Value.SectionID); |
| addRelocationForSection(REmovk_g0, Value.SectionID); |
| } |
| resolveRelocation(Section, Offset, |
| (uint64_t)Section.Address + Section.StubOffset, |
| RelType, 0); |
| Section.StubOffset += getMaxStubSize(); |
| } |
| } else if (Arch == Triple::arm && |
| (RelType == ELF::R_ARM_PC24 || |
| RelType == ELF::R_ARM_CALL || |
| RelType == ELF::R_ARM_JUMP24)) { |
| // This is an ARM branch relocation, need to use a stub function. |
| DEBUG(dbgs() << "\t\tThis is an ARM branch relocation."); |
| SectionEntry &Section = Sections[SectionID]; |
| |
| // Look for an existing stub. |
| StubMap::const_iterator i = Stubs.find(Value); |
| if (i != Stubs.end()) { |
| resolveRelocation(Section, Offset, |
| (uint64_t)Section.Address + i->second, RelType, 0); |
| DEBUG(dbgs() << " Stub function found\n"); |
| } else { |
| // Create a new stub function. |
| DEBUG(dbgs() << " Create a new stub function\n"); |
| Stubs[Value] = Section.StubOffset; |
| uint8_t *StubTargetAddr = createStubFunction(Section.Address + |
| Section.StubOffset); |
| RelocationEntry RE(SectionID, StubTargetAddr - Section.Address, |
| ELF::R_ARM_PRIVATE_0, Value.Addend); |
| if (Value.SymbolName) |
| addRelocationForSymbol(RE, Value.SymbolName); |
| else |
| addRelocationForSection(RE, Value.SectionID); |
| |
| resolveRelocation(Section, Offset, |
| (uint64_t)Section.Address + Section.StubOffset, |
| RelType, 0); |
| Section.StubOffset += getMaxStubSize(); |
| } |
| } else if ((Arch == Triple::mipsel || Arch == Triple::mips) && |
| RelType == ELF::R_MIPS_26) { |
| // This is an Mips branch relocation, need to use a stub function. |
| DEBUG(dbgs() << "\t\tThis is a Mips branch relocation."); |
| SectionEntry &Section = Sections[SectionID]; |
| uint8_t *Target = Section.Address + Offset; |
| uint32_t *TargetAddress = (uint32_t *)Target; |
| |
| // Extract the addend from the instruction. |
| uint32_t Addend = ((*TargetAddress) & 0x03ffffff) << 2; |
| |
| Value.Addend += Addend; |
| |
| // Look up for existing stub. |
| StubMap::const_iterator i = Stubs.find(Value); |
| if (i != Stubs.end()) { |
| RelocationEntry RE(SectionID, Offset, RelType, i->second); |
| addRelocationForSection(RE, SectionID); |
| DEBUG(dbgs() << " Stub function found\n"); |
| } else { |
| // Create a new stub function. |
| DEBUG(dbgs() << " Create a new stub function\n"); |
| Stubs[Value] = Section.StubOffset; |
| uint8_t *StubTargetAddr = createStubFunction(Section.Address + |
| Section.StubOffset); |
| |
| // Creating Hi and Lo relocations for the filled stub instructions. |
| RelocationEntry REHi(SectionID, |
| StubTargetAddr - Section.Address, |
| ELF::R_MIPS_UNUSED1, Value.Addend); |
| RelocationEntry RELo(SectionID, |
| StubTargetAddr - Section.Address + 4, |
| ELF::R_MIPS_UNUSED2, Value.Addend); |
| |
| if (Value.SymbolName) { |
| addRelocationForSymbol(REHi, Value.SymbolName); |
| addRelocationForSymbol(RELo, Value.SymbolName); |
| } else { |
| addRelocationForSection(REHi, Value.SectionID); |
| addRelocationForSection(RELo, Value.SectionID); |
| } |
| |
| RelocationEntry RE(SectionID, Offset, RelType, Section.StubOffset); |
| addRelocationForSection(RE, SectionID); |
| Section.StubOffset += getMaxStubSize(); |
| } |
| } else if (Arch == Triple::ppc64 || Arch == Triple::ppc64le) { |
| if (RelType == ELF::R_PPC64_REL24) { |
| // A PPC branch relocation will need a stub function if the target is |
| // an external symbol (Symbol::ST_Unknown) or if the target address |
| // is not within the signed 24-bits branch address. |
| SectionEntry &Section = Sections[SectionID]; |
| uint8_t *Target = Section.Address + Offset; |
| bool RangeOverflow = false; |
| if (SymType != SymbolRef::ST_Unknown) { |
| // A function call may points to the .opd entry, so the final symbol value |
| // in calculated based in the relocation values in .opd section. |
| findOPDEntrySection(Obj, ObjSectionToID, Value); |
| uint8_t *RelocTarget = Sections[Value.SectionID].Address + Value.Addend; |
| int32_t delta = static_cast<int32_t>(Target - RelocTarget); |
| // If it is within 24-bits branch range, just set the branch target |
| if (SignExtend32<24>(delta) == delta) { |
| RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); |
| if (Value.SymbolName) |
| addRelocationForSymbol(RE, Value.SymbolName); |
| else |
| addRelocationForSection(RE, Value.SectionID); |
| } else { |
| RangeOverflow = true; |
| } |
| } |
| if (SymType == SymbolRef::ST_Unknown || RangeOverflow == true) { |
| // It is an external symbol (SymbolRef::ST_Unknown) or within a range |
| // larger than 24-bits. |
| StubMap::const_iterator i = Stubs.find(Value); |
| if (i != Stubs.end()) { |
| // Symbol function stub already created, just relocate to it |
| resolveRelocation(Section, Offset, |
| (uint64_t)Section.Address + i->second, RelType, 0); |
| DEBUG(dbgs() << " Stub function found\n"); |
| } else { |
| // Create a new stub function. |
| DEBUG(dbgs() << " Create a new stub function\n"); |
| Stubs[Value] = Section.StubOffset; |
| uint8_t *StubTargetAddr = createStubFunction(Section.Address + |
| Section.StubOffset); |
| RelocationEntry RE(SectionID, StubTargetAddr - Section.Address, |
| ELF::R_PPC64_ADDR64, Value.Addend); |
| |
| // Generates the 64-bits address loads as exemplified in section |
| // 4.5.1 in PPC64 ELF ABI. |
| RelocationEntry REhst(SectionID, |
| StubTargetAddr - Section.Address + 2, |
| ELF::R_PPC64_ADDR16_HIGHEST, Value.Addend); |
| RelocationEntry REhr(SectionID, |
| StubTargetAddr - Section.Address + 6, |
| ELF::R_PPC64_ADDR16_HIGHER, Value.Addend); |
| RelocationEntry REh(SectionID, |
| StubTargetAddr - Section.Address + 14, |
| ELF::R_PPC64_ADDR16_HI, Value.Addend); |
| RelocationEntry REl(SectionID, |
| StubTargetAddr - Section.Address + 18, |
| ELF::R_PPC64_ADDR16_LO, Value.Addend); |
| |
| if (Value.SymbolName) { |
| addRelocationForSymbol(REhst, Value.SymbolName); |
| addRelocationForSymbol(REhr, Value.SymbolName); |
| addRelocationForSymbol(REh, Value.SymbolName); |
| addRelocationForSymbol(REl, Value.SymbolName); |
| } else { |
| addRelocationForSection(REhst, Value.SectionID); |
| addRelocationForSection(REhr, Value.SectionID); |
| addRelocationForSection(REh, Value.SectionID); |
| addRelocationForSection(REl, Value.SectionID); |
| } |
| |
| resolveRelocation(Section, Offset, |
| (uint64_t)Section.Address + Section.StubOffset, |
| RelType, 0); |
| if (SymType == SymbolRef::ST_Unknown) |
| // Restore the TOC for external calls |
| writeInt32BE(Target+4, 0xE8410028); // ld r2,40(r1) |
| Section.StubOffset += getMaxStubSize(); |
| } |
| } |
| } else { |
| RelocationEntry RE(SectionID, Offset, RelType, Value.Addend); |
| // Extra check to avoid relocation againt empty symbols (usually |
| // the R_PPC64_TOC). |
| if (SymType != SymbolRef::ST_Unknown && TargetName.empty()) |
| Value.SymbolName = NULL; |
| |
| if (Value.SymbolName) |
| addRelocationForSymbol(RE, Value.SymbolName); |
| else |
| addRelocationForSection(RE, Value.SectionID); |
| } |
| } else if (Arch == Triple::systemz && |
| (RelType == ELF::R_390_PLT32DBL || |
| RelType == ELF::R_390_GOTENT)) { |
| // Create function stubs for both PLT and GOT references, regardless of |
| // whether the GOT reference is to data or code. The stub contains the |
| // full address of the symbol, as needed by GOT references, and the |
| // executable part only adds an overhead of 8 bytes. |
| // |
| // We could try to conserve space by allocating the code and data |
| // parts of the stub separately. However, as things stand, we allocate |
| // a stub for every relocation, so using a GOT in JIT code should be |
| // no less space efficient than using an explicit constant pool. |
| DEBUG(dbgs() << "\t\tThis is a SystemZ indirect relocation."); |
| SectionEntry &Section = Sections[SectionID]; |
| |
| // Look for an existing stub. |
| StubMap::const_iterator i = Stubs.find(Value); |
| uintptr_t StubAddress; |
| if (i != Stubs.end()) { |
| StubAddress = uintptr_t(Section.Address) + i->second; |
| DEBUG(dbgs() << " Stub function found\n"); |
| } else { |
| // Create a new stub function. |
| DEBUG(dbgs() << " Create a new stub function\n"); |
| |
| uintptr_t BaseAddress = uintptr_t(Section.Address); |
| uintptr_t StubAlignment = getStubAlignment(); |
| StubAddress = (BaseAddress + Section.StubOffset + |
| StubAlignment - 1) & -StubAlignment; |
| unsigned StubOffset = StubAddress - BaseAddress; |
| |
| Stubs[Value] = StubOffset; |
| createStubFunction((uint8_t *)StubAddress); |
| RelocationEntry RE(SectionID, StubOffset + 8, |
| ELF::R_390_64, Value.Addend - Addend); |
| if (Value.SymbolName) |
| addRelocationForSymbol(RE, Value.SymbolName); |
| else |
| addRelocationForSection(RE, Value.SectionID); |
| Section.StubOffset = StubOffset + getMaxStubSize(); |
| } |
| |
| if (RelType == ELF::R_390_GOTENT) |
| resolveRelocation(Section, Offset, StubAddress + 8, |
| ELF::R_390_PC32DBL, Addend); |
| else |
| resolveRelocation(Section, Offset, StubAddress, RelType, Addend); |
| } else if (Arch == Triple::x86_64 && RelType == ELF::R_X86_64_PLT32) { |
| // The way the PLT relocations normally work is that the linker allocates the |
| // PLT and this relocation makes a PC-relative call into the PLT. The PLT |
| // entry will then jump to an address provided by the GOT. On first call, the |
| // GOT address will point back into PLT code that resolves the symbol. After |
| // the first call, the GOT entry points to the actual function. |
| // |
| // For local functions we're ignoring all of that here and just replacing |
| // the PLT32 relocation type with PC32, which will translate the relocation |
| // into a PC-relative call directly to the function. For external symbols we |
| // can't be sure the function will be within 2^32 bytes of the call site, so |
| // we need to create a stub, which calls into the GOT. This case is |
| // equivalent to the usual PLT implementation except that we use the stub |
| // mechanism in RuntimeDyld (which puts stubs at the end of the section) |
| // rather than allocating a PLT section. |
| if (Value.SymbolName) { |
| // This is a call to an external function. |
| // Look for an existing stub. |
| SectionEntry &Section = Sections[SectionID]; |
| StubMap::const_iterator i = Stubs.find(Value); |
| uintptr_t StubAddress; |
| if (i != Stubs.end()) { |
| StubAddress = uintptr_t(Section.Address) + i->second; |
| DEBUG(dbgs() << " Stub function found\n"); |
| } else { |
| // Create a new stub function (equivalent to a PLT entry). |
| DEBUG(dbgs() << " Create a new stub function\n"); |
| |
| uintptr_t BaseAddress = uintptr_t(Section.Address); |
| uintptr_t StubAlignment = getStubAlignment(); |
| StubAddress = (BaseAddress + Section.StubOffset + |
| StubAlignment - 1) & -StubAlignment; |
| unsigned StubOffset = StubAddress - BaseAddress; |
| Stubs[Value] = StubOffset; |
| createStubFunction((uint8_t *)StubAddress); |
| |
| // Create a GOT entry for the external function. |
| GOTEntries.push_back(Value); |
| |
| // Make our stub function a relative call to the GOT entry. |
| RelocationEntry RE(SectionID, StubOffset + 2, |
| ELF::R_X86_64_GOTPCREL, -4); |
| addRelocationForSymbol(RE, Value.SymbolName); |
| |
| // Bump our stub offset counter |
| Section.StubOffset = StubOffset + getMaxStubSize(); |
| } |
| |
| // Make the target call a call into the stub table. |
| resolveRelocation(Section, Offset, StubAddress, |
| ELF::R_X86_64_PC32, Addend); |
| } else { |
| RelocationEntry RE(SectionID, Offset, ELF::R_X86_64_PC32, Value.Addend, |
| Value.Offset); |
| addRelocationForSection(RE, Value.SectionID); |
| } |
| } else { |
| if (Arch == Triple::x86_64 && RelType == ELF::R_X86_64_GOTPCREL) { |
| GOTEntries.push_back(Value); |
| } |
| RelocationEntry RE(SectionID, Offset, RelType, Value.Addend, Value.Offset); |
| if (Value.SymbolName) |
| addRelocationForSymbol(RE, Value.SymbolName); |
| else |
| addRelocationForSection(RE, Value.SectionID); |
| } |
| } |
| |
| void RuntimeDyldELF::updateGOTEntries(StringRef Name, uint64_t Addr) { |
| |
| SmallVectorImpl<std::pair<SID, GOTRelocations> >::iterator it; |
| SmallVectorImpl<std::pair<SID, GOTRelocations> >::iterator end = GOTs.end(); |
| |
| for (it = GOTs.begin(); it != end; ++it) { |
| GOTRelocations &GOTEntries = it->second; |
| for (int i = 0, e = GOTEntries.size(); i != e; ++i) { |
| if (GOTEntries[i].SymbolName != 0 && GOTEntries[i].SymbolName == Name) { |
| GOTEntries[i].Offset = Addr; |
| } |
| } |
| } |
| } |
| |
| size_t RuntimeDyldELF::getGOTEntrySize() { |
| // We don't use the GOT in all of these cases, but it's essentially free |
| // to put them all here. |
| size_t Result = 0; |
| switch (Arch) { |
| case Triple::x86_64: |
| case Triple::aarch64: |
| case Triple::ppc64: |
| case Triple::ppc64le: |
| case Triple::systemz: |
| Result = sizeof(uint64_t); |
| break; |
| case Triple::x86: |
| case Triple::arm: |
| case Triple::thumb: |
| case Triple::mips: |
| case Triple::mipsel: |
| Result = sizeof(uint32_t); |
| break; |
| default: llvm_unreachable("Unsupported CPU type!"); |
| } |
| return Result; |
| } |
| |
| uint64_t RuntimeDyldELF::findGOTEntry(uint64_t LoadAddress, |
| uint64_t Offset) { |
| |
| const size_t GOTEntrySize = getGOTEntrySize(); |
| |
| SmallVectorImpl<std::pair<SID, GOTRelocations> >::const_iterator it; |
| SmallVectorImpl<std::pair<SID, GOTRelocations> >::const_iterator end = GOTs.end(); |
| |
| int GOTIndex = -1; |
| for (it = GOTs.begin(); it != end; ++it) { |
| SID GOTSectionID = it->first; |
| const GOTRelocations &GOTEntries = it->second; |
| |
| // Find the matching entry in our vector. |
| uint64_t SymbolOffset = 0; |
| for (int i = 0, e = GOTEntries.size(); i != e; ++i) { |
| if (GOTEntries[i].SymbolName == 0) { |
| if (getSectionLoadAddress(GOTEntries[i].SectionID) == LoadAddress && |
| GOTEntries[i].Offset == Offset) { |
| GOTIndex = i; |
| SymbolOffset = GOTEntries[i].Offset; |
| break; |
| } |
| } else { |
| // GOT entries for external symbols use the addend as the address when |
| // the external symbol has been resolved. |
| if (GOTEntries[i].Offset == LoadAddress) { |
| GOTIndex = i; |
| // Don't use the Addend here. The relocation handler will use it. |
| break; |
| } |
| } |
| } |
| |
| if (GOTIndex != -1) { |
| if (GOTEntrySize == sizeof(uint64_t)) { |
| uint64_t *LocalGOTAddr = (uint64_t*)getSectionAddress(GOTSectionID); |
| // Fill in this entry with the address of the symbol being referenced. |
| LocalGOTAddr[GOTIndex] = LoadAddress + SymbolOffset; |
| } else { |
| uint32_t *LocalGOTAddr = (uint32_t*)getSectionAddress(GOTSectionID); |
| // Fill in this entry with the address of the symbol being referenced. |
| LocalGOTAddr[GOTIndex] = (uint32_t)(LoadAddress + SymbolOffset); |
| } |
| |
| // Calculate the load address of this entry |
| return getSectionLoadAddress(GOTSectionID) + (GOTIndex * GOTEntrySize); |
| } |
| } |
| |
| assert(GOTIndex != -1 && "Unable to find requested GOT entry."); |
| return 0; |
| } |
| |
| void RuntimeDyldELF::finalizeLoad(ObjSectionToIDMap &SectionMap) { |
| // If necessary, allocate the global offset table |
| if (MemMgr) { |
| // Allocate the GOT if necessary |
| size_t numGOTEntries = GOTEntries.size(); |
| if (numGOTEntries != 0) { |
| // Allocate memory for the section |
| unsigned SectionID = Sections.size(); |
| size_t TotalSize = numGOTEntries * getGOTEntrySize(); |
| uint8_t *Addr = MemMgr->allocateDataSection(TotalSize, getGOTEntrySize(), |
| SectionID, ".got", false); |
| if (!Addr) |
| report_fatal_error("Unable to allocate memory for GOT!"); |
| |
| GOTs.push_back(std::make_pair(SectionID, GOTEntries)); |
| Sections.push_back(SectionEntry(".got", Addr, TotalSize, 0)); |
| // For now, initialize all GOT entries to zero. We'll fill them in as |
| // needed when GOT-based relocations are applied. |
| memset(Addr, 0, TotalSize); |
| } |
| } |
| else { |
| report_fatal_error("Unable to allocate memory for GOT!"); |
| } |
| |
| // Look for and record the EH frame section. |
| ObjSectionToIDMap::iterator i, e; |
| for (i = SectionMap.begin(), e = SectionMap.end(); i != e; ++i) { |
| const SectionRef &Section = i->first; |
| StringRef Name; |
| Section.getName(Name); |
| if (Name == ".eh_frame") { |
| UnregisteredEHFrameSections.push_back(i->second); |
| break; |
| } |
| } |
| } |
| |
| bool RuntimeDyldELF::isCompatibleFormat(const ObjectBuffer *Buffer) const { |
| if (Buffer->getBufferSize() < strlen(ELF::ElfMagic)) |
| return false; |
| return (memcmp(Buffer->getBufferStart(), ELF::ElfMagic, strlen(ELF::ElfMagic))) == 0; |
| } |
| } // namespace llvm |
