| //===---- RuntimeDyldMachOI386.h ---- MachO/I386 specific code. ---*- C++ -*-=// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDMACHOI386_H |
| #define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDMACHOI386_H |
| |
| #include "../RuntimeDyldMachO.h" |
| #include <string> |
| |
| #define DEBUG_TYPE "dyld" |
| |
| namespace llvm { |
| |
| class RuntimeDyldMachOI386 |
| : public RuntimeDyldMachOCRTPBase<RuntimeDyldMachOI386> { |
| public: |
| |
| typedef uint32_t TargetPtrT; |
| |
| RuntimeDyldMachOI386(RuntimeDyld::MemoryManager &MM, |
| JITSymbolResolver &Resolver) |
| : RuntimeDyldMachOCRTPBase(MM, Resolver) {} |
| |
| unsigned getMaxStubSize() const override { return 0; } |
| |
| unsigned getStubAlignment() override { return 1; } |
| |
| Expected<relocation_iterator> |
| processRelocationRef(unsigned SectionID, relocation_iterator RelI, |
| const ObjectFile &BaseObjT, |
| ObjSectionToIDMap &ObjSectionToID, |
| StubMap &Stubs) override { |
| const MachOObjectFile &Obj = |
| static_cast<const MachOObjectFile &>(BaseObjT); |
| MachO::any_relocation_info RelInfo = |
| Obj.getRelocation(RelI->getRawDataRefImpl()); |
| uint32_t RelType = Obj.getAnyRelocationType(RelInfo); |
| |
| if (Obj.isRelocationScattered(RelInfo)) { |
| if (RelType == MachO::GENERIC_RELOC_SECTDIFF || |
| RelType == MachO::GENERIC_RELOC_LOCAL_SECTDIFF) |
| return processSECTDIFFRelocation(SectionID, RelI, Obj, |
| ObjSectionToID); |
| else if (RelType == MachO::GENERIC_RELOC_VANILLA) |
| return processScatteredVANILLA(SectionID, RelI, Obj, ObjSectionToID); |
| return make_error<RuntimeDyldError>(("Unhandled I386 scattered relocation " |
| "type: " + Twine(RelType)).str()); |
| } |
| |
| switch (RelType) { |
| UNIMPLEMENTED_RELOC(MachO::GENERIC_RELOC_PAIR); |
| UNIMPLEMENTED_RELOC(MachO::GENERIC_RELOC_PB_LA_PTR); |
| UNIMPLEMENTED_RELOC(MachO::GENERIC_RELOC_TLV); |
| default: |
| if (RelType > MachO::GENERIC_RELOC_TLV) |
| return make_error<RuntimeDyldError>(("MachO I386 relocation type " + |
| Twine(RelType) + |
| " is out of range").str()); |
| break; |
| } |
| |
| RelocationEntry RE(getRelocationEntry(SectionID, Obj, RelI)); |
| RE.Addend = memcpyAddend(RE); |
| RelocationValueRef Value; |
| if (auto ValueOrErr = getRelocationValueRef(Obj, RelI, RE, ObjSectionToID)) |
| Value = *ValueOrErr; |
| else |
| return ValueOrErr.takeError(); |
| |
| // Addends for external, PC-rel relocations on i386 point back to the zero |
| // offset. Calculate the final offset from the relocation target instead. |
| // This allows us to use the same logic for both external and internal |
| // relocations in resolveI386RelocationRef. |
| // bool IsExtern = Obj.getPlainRelocationExternal(RelInfo); |
| // if (IsExtern && RE.IsPCRel) { |
| // uint64_t RelocAddr = 0; |
| // RelI->getAddress(RelocAddr); |
| // Value.Addend += RelocAddr + 4; |
| // } |
| if (RE.IsPCRel) |
| makeValueAddendPCRel(Value, RelI, 1 << RE.Size); |
| |
| RE.Addend = Value.Offset; |
| |
| if (Value.SymbolName) |
| addRelocationForSymbol(RE, Value.SymbolName); |
| else |
| addRelocationForSection(RE, Value.SectionID); |
| |
| return ++RelI; |
| } |
| |
| void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override { |
| LLVM_DEBUG(dumpRelocationToResolve(RE, Value)); |
| |
| const SectionEntry &Section = Sections[RE.SectionID]; |
| uint8_t *LocalAddress = Section.getAddressWithOffset(RE.Offset); |
| |
| if (RE.IsPCRel) { |
| uint64_t FinalAddress = Section.getLoadAddressWithOffset(RE.Offset); |
| Value -= FinalAddress + 4; // see MachOX86_64::resolveRelocation. |
| } |
| |
| switch (RE.RelType) { |
| case MachO::GENERIC_RELOC_VANILLA: |
| writeBytesUnaligned(Value + RE.Addend, LocalAddress, 1 << RE.Size); |
| break; |
| case MachO::GENERIC_RELOC_SECTDIFF: |
| case MachO::GENERIC_RELOC_LOCAL_SECTDIFF: { |
| uint64_t SectionABase = Sections[RE.Sections.SectionA].getLoadAddress(); |
| uint64_t SectionBBase = Sections[RE.Sections.SectionB].getLoadAddress(); |
| assert((Value == SectionABase || Value == SectionBBase) && |
| "Unexpected SECTDIFF relocation value."); |
| Value = SectionABase - SectionBBase + RE.Addend; |
| writeBytesUnaligned(Value, LocalAddress, 1 << RE.Size); |
| break; |
| } |
| default: |
| llvm_unreachable("Invalid relocation type!"); |
| } |
| } |
| |
| Error finalizeSection(const ObjectFile &Obj, unsigned SectionID, |
| const SectionRef &Section) { |
| StringRef Name; |
| Section.getName(Name); |
| |
| if (Name == "__jump_table") |
| return populateJumpTable(cast<MachOObjectFile>(Obj), Section, SectionID); |
| else if (Name == "__pointers") |
| return populateIndirectSymbolPointersSection(cast<MachOObjectFile>(Obj), |
| Section, SectionID); |
| return Error::success(); |
| } |
| |
| private: |
| Expected<relocation_iterator> |
| processSECTDIFFRelocation(unsigned SectionID, relocation_iterator RelI, |
| const ObjectFile &BaseObjT, |
| ObjSectionToIDMap &ObjSectionToID) { |
| const MachOObjectFile &Obj = |
| static_cast<const MachOObjectFile&>(BaseObjT); |
| MachO::any_relocation_info RE = |
| Obj.getRelocation(RelI->getRawDataRefImpl()); |
| |
| SectionEntry &Section = Sections[SectionID]; |
| uint32_t RelocType = Obj.getAnyRelocationType(RE); |
| bool IsPCRel = Obj.getAnyRelocationPCRel(RE); |
| unsigned Size = Obj.getAnyRelocationLength(RE); |
| uint64_t Offset = RelI->getOffset(); |
| uint8_t *LocalAddress = Section.getAddressWithOffset(Offset); |
| unsigned NumBytes = 1 << Size; |
| uint64_t Addend = readBytesUnaligned(LocalAddress, NumBytes); |
| |
| ++RelI; |
| MachO::any_relocation_info RE2 = |
| Obj.getRelocation(RelI->getRawDataRefImpl()); |
| |
| uint32_t AddrA = Obj.getScatteredRelocationValue(RE); |
| section_iterator SAI = getSectionByAddress(Obj, AddrA); |
| assert(SAI != Obj.section_end() && "Can't find section for address A"); |
| uint64_t SectionABase = SAI->getAddress(); |
| uint64_t SectionAOffset = AddrA - SectionABase; |
| SectionRef SectionA = *SAI; |
| bool IsCode = SectionA.isText(); |
| uint32_t SectionAID = ~0U; |
| if (auto SectionAIDOrErr = |
| findOrEmitSection(Obj, SectionA, IsCode, ObjSectionToID)) |
| SectionAID = *SectionAIDOrErr; |
| else |
| return SectionAIDOrErr.takeError(); |
| |
| uint32_t AddrB = Obj.getScatteredRelocationValue(RE2); |
| section_iterator SBI = getSectionByAddress(Obj, AddrB); |
| assert(SBI != Obj.section_end() && "Can't find section for address B"); |
| uint64_t SectionBBase = SBI->getAddress(); |
| uint64_t SectionBOffset = AddrB - SectionBBase; |
| SectionRef SectionB = *SBI; |
| uint32_t SectionBID = ~0U; |
| if (auto SectionBIDOrErr = |
| findOrEmitSection(Obj, SectionB, IsCode, ObjSectionToID)) |
| SectionBID = *SectionBIDOrErr; |
| else |
| return SectionBIDOrErr.takeError(); |
| |
| // Compute the addend 'C' from the original expression 'A - B + C'. |
| Addend -= AddrA - AddrB; |
| |
| LLVM_DEBUG(dbgs() << "Found SECTDIFF: AddrA: " << AddrA |
| << ", AddrB: " << AddrB << ", Addend: " << Addend |
| << ", SectionA ID: " << SectionAID << ", SectionAOffset: " |
| << SectionAOffset << ", SectionB ID: " << SectionBID |
| << ", SectionBOffset: " << SectionBOffset << "\n"); |
| RelocationEntry R(SectionID, Offset, RelocType, Addend, SectionAID, |
| SectionAOffset, SectionBID, SectionBOffset, |
| IsPCRel, Size); |
| |
| addRelocationForSection(R, SectionAID); |
| |
| return ++RelI; |
| } |
| |
| // Populate stubs in __jump_table section. |
| Error populateJumpTable(const MachOObjectFile &Obj, |
| const SectionRef &JTSection, |
| unsigned JTSectionID) { |
| MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand(); |
| MachO::section Sec32 = Obj.getSection(JTSection.getRawDataRefImpl()); |
| uint32_t JTSectionSize = Sec32.size; |
| unsigned FirstIndirectSymbol = Sec32.reserved1; |
| unsigned JTEntrySize = Sec32.reserved2; |
| unsigned NumJTEntries = JTSectionSize / JTEntrySize; |
| uint8_t *JTSectionAddr = getSectionAddress(JTSectionID); |
| unsigned JTEntryOffset = 0; |
| |
| if (JTSectionSize % JTEntrySize != 0) |
| return make_error<RuntimeDyldError>("Jump-table section does not contain " |
| "a whole number of stubs?"); |
| |
| for (unsigned i = 0; i < NumJTEntries; ++i) { |
| unsigned SymbolIndex = |
| Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i); |
| symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex); |
| Expected<StringRef> IndirectSymbolName = SI->getName(); |
| if (!IndirectSymbolName) |
| return IndirectSymbolName.takeError(); |
| uint8_t *JTEntryAddr = JTSectionAddr + JTEntryOffset; |
| createStubFunction(JTEntryAddr); |
| RelocationEntry RE(JTSectionID, JTEntryOffset + 1, |
| MachO::GENERIC_RELOC_VANILLA, 0, true, 2); |
| addRelocationForSymbol(RE, *IndirectSymbolName); |
| JTEntryOffset += JTEntrySize; |
| } |
| |
| return Error::success(); |
| } |
| |
| }; |
| } |
| |
| #undef DEBUG_TYPE |
| |
| #endif |
