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1//===---- RuntimeDyldMachOI386.h ---- MachO/I386 specific code. ---*- C++ -*-=//2//3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.4// See https://llvm.org/LICENSE.txt for license information.5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception6//7//===----------------------------------------------------------------------===//8 9#ifndef LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDMACHOI386_H10#define LLVM_LIB_EXECUTIONENGINE_RUNTIMEDYLD_TARGETS_RUNTIMEDYLDMACHOI386_H11 12#include "../RuntimeDyldMachO.h"13 14#define DEBUG_TYPE "dyld"15 16namespace llvm {17 18class RuntimeDyldMachOI38619 : public RuntimeDyldMachOCRTPBase<RuntimeDyldMachOI386> {20public:21 22 typedef uint32_t TargetPtrT;23 24 RuntimeDyldMachOI386(RuntimeDyld::MemoryManager &MM,25 JITSymbolResolver &Resolver)26 : RuntimeDyldMachOCRTPBase(MM, Resolver) {}27 28 unsigned getMaxStubSize() const override { return 0; }29 30 Align getStubAlignment() override { return Align(1); }31 32 Expected<relocation_iterator>33 processRelocationRef(unsigned SectionID, relocation_iterator RelI,34 const ObjectFile &BaseObjT,35 ObjSectionToIDMap &ObjSectionToID,36 StubMap &Stubs) override {37 const MachOObjectFile &Obj =38 static_cast<const MachOObjectFile &>(BaseObjT);39 MachO::any_relocation_info RelInfo =40 Obj.getRelocation(RelI->getRawDataRefImpl());41 uint32_t RelType = Obj.getAnyRelocationType(RelInfo);42 43 if (Obj.isRelocationScattered(RelInfo)) {44 if (RelType == MachO::GENERIC_RELOC_SECTDIFF ||45 RelType == MachO::GENERIC_RELOC_LOCAL_SECTDIFF)46 return processSECTDIFFRelocation(SectionID, RelI, Obj,47 ObjSectionToID);48 else if (RelType == MachO::GENERIC_RELOC_VANILLA)49 return processScatteredVANILLA(SectionID, RelI, Obj, ObjSectionToID);50 return make_error<RuntimeDyldError>(("Unhandled I386 scattered relocation "51 "type: " + Twine(RelType)).str());52 }53 54 switch (RelType) {55 UNIMPLEMENTED_RELOC(MachO::GENERIC_RELOC_PAIR);56 UNIMPLEMENTED_RELOC(MachO::GENERIC_RELOC_PB_LA_PTR);57 UNIMPLEMENTED_RELOC(MachO::GENERIC_RELOC_TLV);58 default:59 if (RelType > MachO::GENERIC_RELOC_TLV)60 return make_error<RuntimeDyldError>(("MachO I386 relocation type " +61 Twine(RelType) +62 " is out of range").str());63 break;64 }65 66 RelocationEntry RE(getRelocationEntry(SectionID, Obj, RelI));67 RE.Addend = memcpyAddend(RE);68 RelocationValueRef Value;69 if (auto ValueOrErr = getRelocationValueRef(Obj, RelI, RE, ObjSectionToID))70 Value = *ValueOrErr;71 else72 return ValueOrErr.takeError();73 74 // Addends for external, PC-rel relocations on i386 point back to the zero75 // offset. Calculate the final offset from the relocation target instead.76 // This allows us to use the same logic for both external and internal77 // relocations in resolveI386RelocationRef.78 // bool IsExtern = Obj.getPlainRelocationExternal(RelInfo);79 // if (IsExtern && RE.IsPCRel) {80 // uint64_t RelocAddr = 0;81 // RelI->getAddress(RelocAddr);82 // Value.Addend += RelocAddr + 4;83 // }84 if (RE.IsPCRel)85 makeValueAddendPCRel(Value, RelI, 1 << RE.Size);86 87 RE.Addend = Value.Offset;88 89 if (Value.SymbolName)90 addRelocationForSymbol(RE, Value.SymbolName);91 else92 addRelocationForSection(RE, Value.SectionID);93 94 return ++RelI;95 }96 97 void resolveRelocation(const RelocationEntry &RE, uint64_t Value) override {98 LLVM_DEBUG(dumpRelocationToResolve(RE, Value));99 100 const SectionEntry &Section = Sections[RE.SectionID];101 uint8_t *LocalAddress = Section.getAddressWithOffset(RE.Offset);102 103 if (RE.IsPCRel) {104 uint64_t FinalAddress = Section.getLoadAddressWithOffset(RE.Offset);105 Value -= FinalAddress + 4; // see MachOX86_64::resolveRelocation.106 }107 108 switch (RE.RelType) {109 case MachO::GENERIC_RELOC_VANILLA:110 writeBytesUnaligned(Value + RE.Addend, LocalAddress, 1 << RE.Size);111 break;112 case MachO::GENERIC_RELOC_SECTDIFF:113 case MachO::GENERIC_RELOC_LOCAL_SECTDIFF: {114 uint64_t SectionABase = Sections[RE.Sections.SectionA].getLoadAddress();115 uint64_t SectionBBase = Sections[RE.Sections.SectionB].getLoadAddress();116 assert((Value == SectionABase || Value == SectionBBase) &&117 "Unexpected SECTDIFF relocation value.");118 Value = SectionABase - SectionBBase + RE.Addend;119 writeBytesUnaligned(Value, LocalAddress, 1 << RE.Size);120 break;121 }122 default:123 llvm_unreachable("Invalid relocation type!");124 }125 }126 127 Error finalizeSection(const ObjectFile &Obj, unsigned SectionID,128 const SectionRef &Section) {129 StringRef Name;130 if (Expected<StringRef> NameOrErr = Section.getName())131 Name = *NameOrErr;132 else133 consumeError(NameOrErr.takeError());134 135 if (Name == "__jump_table")136 return populateJumpTable(cast<MachOObjectFile>(Obj), Section, SectionID);137 else if (Name == "__pointers")138 return populateIndirectSymbolPointersSection(cast<MachOObjectFile>(Obj),139 Section, SectionID);140 return Error::success();141 }142 143private:144 Expected<relocation_iterator>145 processSECTDIFFRelocation(unsigned SectionID, relocation_iterator RelI,146 const ObjectFile &BaseObjT,147 ObjSectionToIDMap &ObjSectionToID) {148 const MachOObjectFile &Obj =149 static_cast<const MachOObjectFile&>(BaseObjT);150 MachO::any_relocation_info RE =151 Obj.getRelocation(RelI->getRawDataRefImpl());152 153 SectionEntry &Section = Sections[SectionID];154 uint32_t RelocType = Obj.getAnyRelocationType(RE);155 bool IsPCRel = Obj.getAnyRelocationPCRel(RE);156 unsigned Size = Obj.getAnyRelocationLength(RE);157 uint64_t Offset = RelI->getOffset();158 uint8_t *LocalAddress = Section.getAddressWithOffset(Offset);159 unsigned NumBytes = 1 << Size;160 uint64_t Addend = readBytesUnaligned(LocalAddress, NumBytes);161 162 ++RelI;163 MachO::any_relocation_info RE2 =164 Obj.getRelocation(RelI->getRawDataRefImpl());165 166 uint32_t AddrA = Obj.getScatteredRelocationValue(RE);167 section_iterator SAI = getSectionByAddress(Obj, AddrA);168 assert(SAI != Obj.section_end() && "Can't find section for address A");169 uint64_t SectionABase = SAI->getAddress();170 uint64_t SectionAOffset = AddrA - SectionABase;171 SectionRef SectionA = *SAI;172 bool IsCode = SectionA.isText();173 uint32_t SectionAID = ~0U;174 if (auto SectionAIDOrErr =175 findOrEmitSection(Obj, SectionA, IsCode, ObjSectionToID))176 SectionAID = *SectionAIDOrErr;177 else178 return SectionAIDOrErr.takeError();179 180 uint32_t AddrB = Obj.getScatteredRelocationValue(RE2);181 section_iterator SBI = getSectionByAddress(Obj, AddrB);182 assert(SBI != Obj.section_end() && "Can't find section for address B");183 uint64_t SectionBBase = SBI->getAddress();184 uint64_t SectionBOffset = AddrB - SectionBBase;185 SectionRef SectionB = *SBI;186 uint32_t SectionBID = ~0U;187 if (auto SectionBIDOrErr =188 findOrEmitSection(Obj, SectionB, IsCode, ObjSectionToID))189 SectionBID = *SectionBIDOrErr;190 else191 return SectionBIDOrErr.takeError();192 193 // Compute the addend 'C' from the original expression 'A - B + C'.194 Addend -= AddrA - AddrB;195 196 LLVM_DEBUG(dbgs() << "Found SECTDIFF: AddrA: " << AddrA197 << ", AddrB: " << AddrB << ", Addend: " << Addend198 << ", SectionA ID: " << SectionAID << ", SectionAOffset: "199 << SectionAOffset << ", SectionB ID: " << SectionBID200 << ", SectionBOffset: " << SectionBOffset << "\n");201 RelocationEntry R(SectionID, Offset, RelocType, Addend, SectionAID,202 SectionAOffset, SectionBID, SectionBOffset,203 IsPCRel, Size);204 205 addRelocationForSection(R, SectionAID);206 207 return ++RelI;208 }209 210 // Populate stubs in __jump_table section.211 Error populateJumpTable(const MachOObjectFile &Obj,212 const SectionRef &JTSection,213 unsigned JTSectionID) {214 MachO::dysymtab_command DySymTabCmd = Obj.getDysymtabLoadCommand();215 MachO::section Sec32 = Obj.getSection(JTSection.getRawDataRefImpl());216 uint32_t JTSectionSize = Sec32.size;217 unsigned FirstIndirectSymbol = Sec32.reserved1;218 unsigned JTEntrySize = Sec32.reserved2;219 unsigned NumJTEntries = JTSectionSize / JTEntrySize;220 uint8_t *JTSectionAddr = getSectionAddress(JTSectionID);221 unsigned JTEntryOffset = 0;222 223 if (JTSectionSize % JTEntrySize != 0)224 return make_error<RuntimeDyldError>("Jump-table section does not contain "225 "a whole number of stubs?");226 227 for (unsigned i = 0; i < NumJTEntries; ++i) {228 unsigned SymbolIndex =229 Obj.getIndirectSymbolTableEntry(DySymTabCmd, FirstIndirectSymbol + i);230 symbol_iterator SI = Obj.getSymbolByIndex(SymbolIndex);231 Expected<StringRef> IndirectSymbolName = SI->getName();232 if (!IndirectSymbolName)233 return IndirectSymbolName.takeError();234 uint8_t *JTEntryAddr = JTSectionAddr + JTEntryOffset;235 createStubFunction(JTEntryAddr);236 RelocationEntry RE(JTSectionID, JTEntryOffset + 1,237 MachO::GENERIC_RELOC_VANILLA, 0, true, 2);238 addRelocationForSymbol(RE, *IndirectSymbolName);239 JTEntryOffset += JTEntrySize;240 }241 242 return Error::success();243 }244 245};246}247 248#undef DEBUG_TYPE249 250#endif251