| //===---- MachO_x86_64.cpp -JIT linker implementation for MachO/x86-64 ----===// |
| // |
| // 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 |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // MachO/x86-64 jit-link implementation. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "llvm/ExecutionEngine/JITLink/MachO_x86_64.h" |
| #include "llvm/ExecutionEngine/JITLink/x86_64.h" |
| |
| #include "MachOLinkGraphBuilder.h" |
| #include "PerGraphGOTAndPLTStubsBuilder.h" |
| |
| #define DEBUG_TYPE "jitlink" |
| |
| using namespace llvm; |
| using namespace llvm::jitlink; |
| |
| namespace { |
| |
| class MachOLinkGraphBuilder_x86_64 : public MachOLinkGraphBuilder { |
| public: |
| MachOLinkGraphBuilder_x86_64(const object::MachOObjectFile &Obj) |
| : MachOLinkGraphBuilder(Obj, Triple("x86_64-apple-darwin"), |
| x86_64::getEdgeKindName) {} |
| |
| private: |
| enum MachONormalizedRelocationType : unsigned { |
| MachOBranch32, |
| MachOPointer32, |
| MachOPointer64, |
| MachOPointer64Anon, |
| MachOPCRel32, |
| MachOPCRel32Minus1, |
| MachOPCRel32Minus2, |
| MachOPCRel32Minus4, |
| MachOPCRel32Anon, |
| MachOPCRel32Minus1Anon, |
| MachOPCRel32Minus2Anon, |
| MachOPCRel32Minus4Anon, |
| MachOPCRel32GOTLoad, |
| MachOPCRel32GOT, |
| MachOPCRel32TLV, |
| MachOSubtractor32, |
| MachOSubtractor64, |
| }; |
| |
| static Expected<MachONormalizedRelocationType> |
| getRelocKind(const MachO::relocation_info &RI) { |
| switch (RI.r_type) { |
| case MachO::X86_64_RELOC_UNSIGNED: |
| if (!RI.r_pcrel) { |
| if (RI.r_length == 3) |
| return RI.r_extern ? MachOPointer64 : MachOPointer64Anon; |
| else if (RI.r_extern && RI.r_length == 2) |
| return MachOPointer32; |
| } |
| break; |
| case MachO::X86_64_RELOC_SIGNED: |
| if (RI.r_pcrel && RI.r_length == 2) |
| return RI.r_extern ? MachOPCRel32 : MachOPCRel32Anon; |
| break; |
| case MachO::X86_64_RELOC_BRANCH: |
| if (RI.r_pcrel && RI.r_extern && RI.r_length == 2) |
| return MachOBranch32; |
| break; |
| case MachO::X86_64_RELOC_GOT_LOAD: |
| if (RI.r_pcrel && RI.r_extern && RI.r_length == 2) |
| return MachOPCRel32GOTLoad; |
| break; |
| case MachO::X86_64_RELOC_GOT: |
| if (RI.r_pcrel && RI.r_extern && RI.r_length == 2) |
| return MachOPCRel32GOT; |
| break; |
| case MachO::X86_64_RELOC_SUBTRACTOR: |
| if (!RI.r_pcrel && RI.r_extern) { |
| if (RI.r_length == 2) |
| return MachOSubtractor32; |
| else if (RI.r_length == 3) |
| return MachOSubtractor64; |
| } |
| break; |
| case MachO::X86_64_RELOC_SIGNED_1: |
| if (RI.r_pcrel && RI.r_length == 2) |
| return RI.r_extern ? MachOPCRel32Minus1 : MachOPCRel32Minus1Anon; |
| break; |
| case MachO::X86_64_RELOC_SIGNED_2: |
| if (RI.r_pcrel && RI.r_length == 2) |
| return RI.r_extern ? MachOPCRel32Minus2 : MachOPCRel32Minus2Anon; |
| break; |
| case MachO::X86_64_RELOC_SIGNED_4: |
| if (RI.r_pcrel && RI.r_length == 2) |
| return RI.r_extern ? MachOPCRel32Minus4 : MachOPCRel32Minus4Anon; |
| break; |
| case MachO::X86_64_RELOC_TLV: |
| if (RI.r_pcrel && RI.r_extern && RI.r_length == 2) |
| return MachOPCRel32TLV; |
| break; |
| } |
| |
| return make_error<JITLinkError>( |
| "Unsupported x86-64 relocation: address=" + |
| formatv("{0:x8}", RI.r_address) + |
| ", symbolnum=" + formatv("{0:x6}", RI.r_symbolnum) + |
| ", kind=" + formatv("{0:x1}", RI.r_type) + |
| ", pc_rel=" + (RI.r_pcrel ? "true" : "false") + |
| ", extern=" + (RI.r_extern ? "true" : "false") + |
| ", length=" + formatv("{0:d}", RI.r_length)); |
| } |
| |
| using PairRelocInfo = std::tuple<Edge::Kind, Symbol *, uint64_t>; |
| |
| // Parses paired SUBTRACTOR/UNSIGNED relocations and, on success, |
| // returns the edge kind and addend to be used. |
| Expected<PairRelocInfo> parsePairRelocation( |
| Block &BlockToFix, MachONormalizedRelocationType SubtractorKind, |
| const MachO::relocation_info &SubRI, JITTargetAddress FixupAddress, |
| const char *FixupContent, object::relocation_iterator &UnsignedRelItr, |
| object::relocation_iterator &RelEnd) { |
| using namespace support; |
| |
| assert(((SubtractorKind == MachOSubtractor32 && SubRI.r_length == 2) || |
| (SubtractorKind == MachOSubtractor64 && SubRI.r_length == 3)) && |
| "Subtractor kind should match length"); |
| assert(SubRI.r_extern && "SUBTRACTOR reloc symbol should be extern"); |
| assert(!SubRI.r_pcrel && "SUBTRACTOR reloc should not be PCRel"); |
| |
| if (UnsignedRelItr == RelEnd) |
| return make_error<JITLinkError>("x86_64 SUBTRACTOR without paired " |
| "UNSIGNED relocation"); |
| |
| auto UnsignedRI = getRelocationInfo(UnsignedRelItr); |
| |
| if (SubRI.r_address != UnsignedRI.r_address) |
| return make_error<JITLinkError>("x86_64 SUBTRACTOR and paired UNSIGNED " |
| "point to different addresses"); |
| |
| if (SubRI.r_length != UnsignedRI.r_length) |
| return make_error<JITLinkError>("length of x86_64 SUBTRACTOR and paired " |
| "UNSIGNED reloc must match"); |
| |
| Symbol *FromSymbol; |
| if (auto FromSymbolOrErr = findSymbolByIndex(SubRI.r_symbolnum)) |
| FromSymbol = FromSymbolOrErr->GraphSymbol; |
| else |
| return FromSymbolOrErr.takeError(); |
| |
| // Read the current fixup value. |
| uint64_t FixupValue = 0; |
| if (SubRI.r_length == 3) |
| FixupValue = *(const little64_t *)FixupContent; |
| else |
| FixupValue = *(const little32_t *)FixupContent; |
| |
| // Find 'ToSymbol' using symbol number or address, depending on whether the |
| // paired UNSIGNED relocation is extern. |
| Symbol *ToSymbol = nullptr; |
| if (UnsignedRI.r_extern) { |
| // Find target symbol by symbol index. |
| if (auto ToSymbolOrErr = findSymbolByIndex(UnsignedRI.r_symbolnum)) |
| ToSymbol = ToSymbolOrErr->GraphSymbol; |
| else |
| return ToSymbolOrErr.takeError(); |
| } else { |
| auto ToSymbolSec = findSectionByIndex(UnsignedRI.r_symbolnum - 1); |
| if (!ToSymbolSec) |
| return ToSymbolSec.takeError(); |
| ToSymbol = getSymbolByAddress(ToSymbolSec->Address); |
| assert(ToSymbol && "No symbol for section"); |
| FixupValue -= ToSymbol->getAddress(); |
| } |
| |
| Edge::Kind DeltaKind; |
| Symbol *TargetSymbol; |
| uint64_t Addend; |
| if (&BlockToFix == &FromSymbol->getAddressable()) { |
| TargetSymbol = ToSymbol; |
| DeltaKind = (SubRI.r_length == 3) ? x86_64::Delta64 : x86_64::Delta32; |
| Addend = FixupValue + (FixupAddress - FromSymbol->getAddress()); |
| // FIXME: handle extern 'from'. |
| } else if (&BlockToFix == &ToSymbol->getAddressable()) { |
| TargetSymbol = FromSymbol; |
| DeltaKind = |
| (SubRI.r_length == 3) ? x86_64::NegDelta64 : x86_64::NegDelta32; |
| Addend = FixupValue - (FixupAddress - ToSymbol->getAddress()); |
| } else { |
| // BlockToFix was neither FromSymbol nor ToSymbol. |
| return make_error<JITLinkError>("SUBTRACTOR relocation must fix up " |
| "either 'A' or 'B' (or a symbol in one " |
| "of their alt-entry chains)"); |
| } |
| |
| return PairRelocInfo(DeltaKind, TargetSymbol, Addend); |
| } |
| |
| Error addRelocations() override { |
| using namespace support; |
| auto &Obj = getObject(); |
| |
| LLVM_DEBUG(dbgs() << "Processing relocations:\n"); |
| |
| for (auto &S : Obj.sections()) { |
| |
| JITTargetAddress SectionAddress = S.getAddress(); |
| |
| // Skip relocations virtual sections. |
| if (S.isVirtual()) { |
| if (S.relocation_begin() != S.relocation_end()) |
| return make_error<JITLinkError>("Virtual section contains " |
| "relocations"); |
| continue; |
| } |
| |
| // Skip relocations for debug symbols. |
| { |
| auto &NSec = |
| getSectionByIndex(Obj.getSectionIndex(S.getRawDataRefImpl())); |
| if (!NSec.GraphSection) { |
| LLVM_DEBUG({ |
| dbgs() << " Skipping relocations for MachO section " |
| << NSec.SegName << "/" << NSec.SectName |
| << " which has no associated graph section\n"; |
| }); |
| continue; |
| } |
| } |
| |
| // Add relocations for section. |
| for (auto RelItr = S.relocation_begin(), RelEnd = S.relocation_end(); |
| RelItr != RelEnd; ++RelItr) { |
| |
| MachO::relocation_info RI = getRelocationInfo(RelItr); |
| |
| // Find the address of the value to fix up. |
| JITTargetAddress FixupAddress = SectionAddress + (uint32_t)RI.r_address; |
| |
| LLVM_DEBUG({ |
| auto &NSec = |
| getSectionByIndex(Obj.getSectionIndex(S.getRawDataRefImpl())); |
| dbgs() << " " << NSec.SectName << " + " |
| << formatv("{0:x8}", RI.r_address) << ":\n"; |
| }); |
| |
| // Find the block that the fixup points to. |
| Block *BlockToFix = nullptr; |
| { |
| auto SymbolToFixOrErr = findSymbolByAddress(FixupAddress); |
| if (!SymbolToFixOrErr) |
| return SymbolToFixOrErr.takeError(); |
| BlockToFix = &SymbolToFixOrErr->getBlock(); |
| } |
| |
| if (FixupAddress + static_cast<JITTargetAddress>(1ULL << RI.r_length) > |
| BlockToFix->getAddress() + BlockToFix->getContent().size()) |
| return make_error<JITLinkError>( |
| "Relocation extends past end of fixup block"); |
| |
| // Get a pointer to the fixup content. |
| const char *FixupContent = BlockToFix->getContent().data() + |
| (FixupAddress - BlockToFix->getAddress()); |
| |
| size_t FixupOffset = FixupAddress - BlockToFix->getAddress(); |
| |
| // The target symbol and addend will be populated by the switch below. |
| Symbol *TargetSymbol = nullptr; |
| uint64_t Addend = 0; |
| |
| // Sanity check the relocation kind. |
| auto MachORelocKind = getRelocKind(RI); |
| if (!MachORelocKind) |
| return MachORelocKind.takeError(); |
| |
| Edge::Kind Kind = Edge::Invalid; |
| |
| switch (*MachORelocKind) { |
| case MachOBranch32: |
| if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum)) |
| TargetSymbol = TargetSymbolOrErr->GraphSymbol; |
| else |
| return TargetSymbolOrErr.takeError(); |
| Addend = *(const little32_t *)FixupContent; |
| Kind = x86_64::BranchPCRel32; |
| break; |
| case MachOPCRel32: |
| if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum)) |
| TargetSymbol = TargetSymbolOrErr->GraphSymbol; |
| else |
| return TargetSymbolOrErr.takeError(); |
| Addend = *(const little32_t *)FixupContent - 4; |
| Kind = x86_64::Delta32; |
| break; |
| case MachOPCRel32GOTLoad: |
| if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum)) |
| TargetSymbol = TargetSymbolOrErr->GraphSymbol; |
| else |
| return TargetSymbolOrErr.takeError(); |
| Addend = *(const little32_t *)FixupContent; |
| Kind = x86_64::RequestGOTAndTransformToPCRel32GOTLoadRelaxable; |
| if (FixupOffset < 3) |
| return make_error<JITLinkError>("GOTLD at invalid offset " + |
| formatv("{0}", FixupOffset)); |
| break; |
| case MachOPCRel32GOT: |
| if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum)) |
| TargetSymbol = TargetSymbolOrErr->GraphSymbol; |
| else |
| return TargetSymbolOrErr.takeError(); |
| Addend = *(const little32_t *)FixupContent - 4; |
| Kind = x86_64::RequestGOTAndTransformToDelta32; |
| break; |
| case MachOPointer32: |
| if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum)) |
| TargetSymbol = TargetSymbolOrErr->GraphSymbol; |
| else |
| return TargetSymbolOrErr.takeError(); |
| Addend = *(const ulittle32_t *)FixupContent; |
| Kind = x86_64::Pointer32; |
| break; |
| case MachOPointer64: |
| if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum)) |
| TargetSymbol = TargetSymbolOrErr->GraphSymbol; |
| else |
| return TargetSymbolOrErr.takeError(); |
| Addend = *(const ulittle64_t *)FixupContent; |
| Kind = x86_64::Pointer64; |
| break; |
| case MachOPointer64Anon: { |
| JITTargetAddress TargetAddress = *(const ulittle64_t *)FixupContent; |
| if (auto TargetSymbolOrErr = findSymbolByAddress(TargetAddress)) |
| TargetSymbol = &*TargetSymbolOrErr; |
| else |
| return TargetSymbolOrErr.takeError(); |
| Addend = TargetAddress - TargetSymbol->getAddress(); |
| Kind = x86_64::Pointer64; |
| break; |
| } |
| case MachOPCRel32Minus1: |
| case MachOPCRel32Minus2: |
| case MachOPCRel32Minus4: |
| if (auto TargetSymbolOrErr = findSymbolByIndex(RI.r_symbolnum)) |
| TargetSymbol = TargetSymbolOrErr->GraphSymbol; |
| else |
| return TargetSymbolOrErr.takeError(); |
| Addend = *(const little32_t *)FixupContent - 4; |
| // - |
| // (1 << (*MachORelocKind - MachOPCRel32Minus1)); |
| Kind = x86_64::Delta32; |
| break; |
| case MachOPCRel32Anon: { |
| JITTargetAddress TargetAddress = |
| FixupAddress + 4 + *(const little32_t *)FixupContent; |
| if (auto TargetSymbolOrErr = findSymbolByAddress(TargetAddress)) |
| TargetSymbol = &*TargetSymbolOrErr; |
| else |
| return TargetSymbolOrErr.takeError(); |
| Addend = TargetAddress - TargetSymbol->getAddress() - 4; |
| Kind = x86_64::Delta32; |
| break; |
| } |
| case MachOPCRel32Minus1Anon: |
| case MachOPCRel32Minus2Anon: |
| case MachOPCRel32Minus4Anon: { |
| JITTargetAddress Delta = |
| 4 + static_cast<JITTargetAddress>( |
| 1ULL << (*MachORelocKind - MachOPCRel32Minus1Anon)); |
| JITTargetAddress TargetAddress = |
| FixupAddress + Delta + *(const little32_t *)FixupContent; |
| if (auto TargetSymbolOrErr = findSymbolByAddress(TargetAddress)) |
| TargetSymbol = &*TargetSymbolOrErr; |
| else |
| return TargetSymbolOrErr.takeError(); |
| Addend = TargetAddress - TargetSymbol->getAddress() - Delta; |
| Kind = x86_64::Delta32; |
| break; |
| } |
| case MachOSubtractor32: |
| case MachOSubtractor64: { |
| // We use Delta32/Delta64 to represent SUBTRACTOR relocations. |
| // parsePairRelocation handles the paired reloc, and returns the |
| // edge kind to be used (either Delta32/Delta64, or |
| // NegDelta32/NegDelta64, depending on the direction of the |
| // subtraction) along with the addend. |
| auto PairInfo = |
| parsePairRelocation(*BlockToFix, *MachORelocKind, RI, |
| FixupAddress, FixupContent, ++RelItr, RelEnd); |
| if (!PairInfo) |
| return PairInfo.takeError(); |
| std::tie(Kind, TargetSymbol, Addend) = *PairInfo; |
| assert(TargetSymbol && "No target symbol from parsePairRelocation?"); |
| break; |
| } |
| case MachOPCRel32TLV: |
| return make_error<JITLinkError>( |
| "MachO TLV relocations not yet supported"); |
| } |
| |
| LLVM_DEBUG({ |
| dbgs() << " "; |
| Edge GE(Kind, FixupAddress - BlockToFix->getAddress(), *TargetSymbol, |
| Addend); |
| printEdge(dbgs(), *BlockToFix, GE, x86_64::getEdgeKindName(Kind)); |
| dbgs() << "\n"; |
| }); |
| BlockToFix->addEdge(Kind, FixupAddress - BlockToFix->getAddress(), |
| *TargetSymbol, Addend); |
| } |
| } |
| return Error::success(); |
| } |
| }; |
| |
| class PerGraphGOTAndPLTStubsBuilder_MachO_x86_64 |
| : public PerGraphGOTAndPLTStubsBuilder< |
| PerGraphGOTAndPLTStubsBuilder_MachO_x86_64> { |
| public: |
| static const uint8_t NullGOTEntryContent[8]; |
| static const uint8_t StubContent[6]; |
| |
| using PerGraphGOTAndPLTStubsBuilder< |
| PerGraphGOTAndPLTStubsBuilder_MachO_x86_64>:: |
| PerGraphGOTAndPLTStubsBuilder; |
| |
| bool isGOTEdgeToFix(Edge &E) const { |
| return E.getKind() == x86_64::RequestGOTAndTransformToDelta32 || |
| E.getKind() == |
| x86_64::RequestGOTAndTransformToPCRel32GOTLoadRelaxable; |
| } |
| |
| Symbol &createGOTEntry(Symbol &Target) { |
| auto &GOTEntryBlock = G.createContentBlock( |
| getGOTSection(), getGOTEntryBlockContent(), 0, 8, 0); |
| GOTEntryBlock.addEdge(x86_64::Pointer64, 0, Target, 0); |
| return G.addAnonymousSymbol(GOTEntryBlock, 0, 8, false, false); |
| } |
| |
| void fixGOTEdge(Edge &E, Symbol &GOTEntry) { |
| // Fix the edge kind. |
| switch (E.getKind()) { |
| case x86_64::RequestGOTAndTransformToDelta32: |
| E.setKind(x86_64::Delta32); |
| break; |
| case x86_64::RequestGOTAndTransformToPCRel32GOTLoadRelaxable: |
| E.setKind(x86_64::PCRel32GOTLoadRelaxable); |
| break; |
| default: |
| llvm_unreachable("Not a GOT transform edge"); |
| } |
| // Fix the target, leave the addend as-is. |
| E.setTarget(GOTEntry); |
| } |
| |
| bool isExternalBranchEdge(Edge &E) { |
| return E.getKind() == x86_64::BranchPCRel32 && E.getTarget().isExternal(); |
| } |
| |
| Symbol &createPLTStub(Symbol &Target) { |
| auto &StubContentBlock = |
| G.createContentBlock(getStubsSection(), getStubBlockContent(), 0, 1, 0); |
| // Re-use GOT entries for stub targets. |
| auto &GOTEntrySymbol = getGOTEntry(Target); |
| StubContentBlock.addEdge(x86_64::Delta32, 2, GOTEntrySymbol, -4); |
| return G.addAnonymousSymbol(StubContentBlock, 0, 6, true, false); |
| } |
| |
| void fixPLTEdge(Edge &E, Symbol &Stub) { |
| assert(E.getKind() == x86_64::BranchPCRel32 && "Not a Branch32 edge?"); |
| assert(E.getAddend() == 0 && |
| "BranchPCRel32 edge has unexpected addend value"); |
| |
| // Set the edge kind to BranchPCRel32ToPtrJumpStubRelaxable. We will use |
| // this to check for stub optimization opportunities in the |
| // optimizeMachO_x86_64_GOTAndStubs pass below. |
| E.setKind(x86_64::BranchPCRel32ToPtrJumpStubRelaxable); |
| E.setTarget(Stub); |
| } |
| |
| private: |
| Section &getGOTSection() { |
| if (!GOTSection) |
| GOTSection = &G.createSection("$__GOT", sys::Memory::MF_READ); |
| return *GOTSection; |
| } |
| |
| Section &getStubsSection() { |
| if (!StubsSection) { |
| auto StubsProt = static_cast<sys::Memory::ProtectionFlags>( |
| sys::Memory::MF_READ | sys::Memory::MF_EXEC); |
| StubsSection = &G.createSection("$__STUBS", StubsProt); |
| } |
| return *StubsSection; |
| } |
| |
| StringRef getGOTEntryBlockContent() { |
| return StringRef(reinterpret_cast<const char *>(NullGOTEntryContent), |
| sizeof(NullGOTEntryContent)); |
| } |
| |
| StringRef getStubBlockContent() { |
| return StringRef(reinterpret_cast<const char *>(StubContent), |
| sizeof(StubContent)); |
| } |
| |
| Section *GOTSection = nullptr; |
| Section *StubsSection = nullptr; |
| }; |
| |
| const uint8_t |
| PerGraphGOTAndPLTStubsBuilder_MachO_x86_64::NullGOTEntryContent[8] = { |
| 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; |
| const uint8_t PerGraphGOTAndPLTStubsBuilder_MachO_x86_64::StubContent[6] = { |
| 0xFF, 0x25, 0x00, 0x00, 0x00, 0x00}; |
| } // namespace |
| |
| static Error optimizeMachO_x86_64_GOTAndStubs(LinkGraph &G) { |
| LLVM_DEBUG(dbgs() << "Optimizing GOT entries and stubs:\n"); |
| |
| for (auto *B : G.blocks()) |
| for (auto &E : B->edges()) |
| if (E.getKind() == x86_64::PCRel32GOTLoadRelaxable) { |
| assert(E.getOffset() >= 3 && "GOT edge occurs too early in block"); |
| |
| // Optimize GOT references. |
| auto &GOTBlock = E.getTarget().getBlock(); |
| assert(GOTBlock.getSize() == G.getPointerSize() && |
| "GOT entry block should be pointer sized"); |
| assert(GOTBlock.edges_size() == 1 && |
| "GOT entry should only have one outgoing edge"); |
| |
| auto &GOTTarget = GOTBlock.edges().begin()->getTarget(); |
| JITTargetAddress EdgeAddr = B->getAddress() + E.getOffset(); |
| JITTargetAddress TargetAddr = GOTTarget.getAddress(); |
| |
| // Check that this is a recognized MOV instruction. |
| // FIXME: Can we assume this? |
| constexpr uint8_t MOVQRIPRel[] = {0x48, 0x8b}; |
| if (strncmp(B->getContent().data() + E.getOffset() - 3, |
| reinterpret_cast<const char *>(MOVQRIPRel), 2) != 0) |
| continue; |
| |
| int64_t Displacement = TargetAddr - EdgeAddr + 4; |
| if (Displacement >= std::numeric_limits<int32_t>::min() && |
| Displacement <= std::numeric_limits<int32_t>::max()) { |
| E.setTarget(GOTTarget); |
| E.setKind(x86_64::Delta32); |
| E.setAddend(E.getAddend() - 4); |
| auto *BlockData = reinterpret_cast<uint8_t *>( |
| const_cast<char *>(B->getContent().data())); |
| BlockData[E.getOffset() - 2] = 0x8d; |
| LLVM_DEBUG({ |
| dbgs() << " Replaced GOT load wih LEA:\n "; |
| printEdge(dbgs(), *B, E, x86_64::getEdgeKindName(E.getKind())); |
| dbgs() << "\n"; |
| }); |
| } |
| } else if (E.getKind() == x86_64::BranchPCRel32ToPtrJumpStubRelaxable) { |
| auto &StubBlock = E.getTarget().getBlock(); |
| assert( |
| StubBlock.getSize() == |
| sizeof( |
| PerGraphGOTAndPLTStubsBuilder_MachO_x86_64::StubContent) && |
| "Stub block should be stub sized"); |
| assert(StubBlock.edges_size() == 1 && |
| "Stub block should only have one outgoing edge"); |
| |
| auto &GOTBlock = StubBlock.edges().begin()->getTarget().getBlock(); |
| assert(GOTBlock.getSize() == G.getPointerSize() && |
| "GOT block should be pointer sized"); |
| assert(GOTBlock.edges_size() == 1 && |
| "GOT block should only have one outgoing edge"); |
| |
| auto &GOTTarget = GOTBlock.edges().begin()->getTarget(); |
| JITTargetAddress EdgeAddr = B->getAddress() + E.getOffset(); |
| JITTargetAddress TargetAddr = GOTTarget.getAddress(); |
| |
| int64_t Displacement = TargetAddr - EdgeAddr + 4; |
| if (Displacement >= std::numeric_limits<int32_t>::min() && |
| Displacement <= std::numeric_limits<int32_t>::max()) { |
| E.setKind(x86_64::BranchPCRel32); |
| E.setTarget(GOTTarget); |
| LLVM_DEBUG({ |
| dbgs() << " Replaced stub branch with direct branch:\n "; |
| printEdge(dbgs(), *B, E, x86_64::getEdgeKindName(E.getKind())); |
| dbgs() << "\n"; |
| }); |
| } |
| } |
| |
| return Error::success(); |
| } |
| |
| namespace llvm { |
| namespace jitlink { |
| |
| class MachOJITLinker_x86_64 : public JITLinker<MachOJITLinker_x86_64> { |
| friend class JITLinker<MachOJITLinker_x86_64>; |
| |
| public: |
| MachOJITLinker_x86_64(std::unique_ptr<JITLinkContext> Ctx, |
| std::unique_ptr<LinkGraph> G, |
| PassConfiguration PassConfig) |
| : JITLinker(std::move(Ctx), std::move(G), std::move(PassConfig)) {} |
| |
| private: |
| Error applyFixup(LinkGraph &G, Block &B, const Edge &E, |
| char *BlockWorkingMem) const { |
| return x86_64::applyFixup(G, B, E, BlockWorkingMem); |
| } |
| }; |
| |
| Expected<std::unique_ptr<LinkGraph>> |
| createLinkGraphFromMachOObject_x86_64(MemoryBufferRef ObjectBuffer) { |
| auto MachOObj = object::ObjectFile::createMachOObjectFile(ObjectBuffer); |
| if (!MachOObj) |
| return MachOObj.takeError(); |
| return MachOLinkGraphBuilder_x86_64(**MachOObj).buildGraph(); |
| } |
| |
| void link_MachO_x86_64(std::unique_ptr<LinkGraph> G, |
| std::unique_ptr<JITLinkContext> Ctx) { |
| |
| PassConfiguration Config; |
| |
| if (Ctx->shouldAddDefaultTargetPasses(G->getTargetTriple())) { |
| // Add eh-frame passses. |
| Config.PrePrunePasses.push_back(EHFrameSplitter("__eh_frame")); |
| Config.PrePrunePasses.push_back( |
| EHFrameEdgeFixer("__eh_frame", G->getPointerSize(), x86_64::Delta64, |
| x86_64::Delta32, x86_64::NegDelta32)); |
| |
| // Add a mark-live pass. |
| if (auto MarkLive = Ctx->getMarkLivePass(G->getTargetTriple())) |
| Config.PrePrunePasses.push_back(std::move(MarkLive)); |
| else |
| Config.PrePrunePasses.push_back(markAllSymbolsLive); |
| |
| // Add an in-place GOT/Stubs pass. |
| Config.PostPrunePasses.push_back( |
| PerGraphGOTAndPLTStubsBuilder_MachO_x86_64::asPass); |
| |
| // Add GOT/Stubs optimizer pass. |
| Config.PreFixupPasses.push_back(optimizeMachO_x86_64_GOTAndStubs); |
| } |
| |
| if (auto Err = Ctx->modifyPassConfig(*G, Config)) |
| return Ctx->notifyFailed(std::move(Err)); |
| |
| // Construct a JITLinker and run the link function. |
| MachOJITLinker_x86_64::link(std::move(Ctx), std::move(G), std::move(Config)); |
| } |
| |
| } // end namespace jitlink |
| } // end namespace llvm |
