diff options
Diffstat (limited to 'lib/ExecutionEngine/JITLink/MachO_x86_64.cpp')
| -rw-r--r-- | lib/ExecutionEngine/JITLink/MachO_x86_64.cpp | 608 |
1 files changed, 608 insertions, 0 deletions
diff --git a/lib/ExecutionEngine/JITLink/MachO_x86_64.cpp b/lib/ExecutionEngine/JITLink/MachO_x86_64.cpp new file mode 100644 index 0000000000000..4010678c6d33c --- /dev/null +++ b/lib/ExecutionEngine/JITLink/MachO_x86_64.cpp @@ -0,0 +1,608 @@ +//===---- 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 "BasicGOTAndStubsBuilder.h" +#include "MachOAtomGraphBuilder.h" + +#define DEBUG_TYPE "jitlink" + +using namespace llvm; +using namespace llvm::jitlink; +using namespace llvm::jitlink::MachO_x86_64_Edges; + +namespace { + +class MachOAtomGraphBuilder_x86_64 : public MachOAtomGraphBuilder { +public: + MachOAtomGraphBuilder_x86_64(const object::MachOObjectFile &Obj) + : MachOAtomGraphBuilder(Obj), + NumSymbols(Obj.getSymtabLoadCommand().nsyms) { + addCustomAtomizer("__eh_frame", [this](MachOSection &EHFrameSection) { + return addEHFrame(getGraph(), EHFrameSection.getGenericSection(), + EHFrameSection.getContent(), + EHFrameSection.getAddress(), NegDelta32, Delta64); + }); + } + +private: + static Expected<MachOX86RelocationKind> + getRelocationKind(const MachO::relocation_info &RI) { + switch (RI.r_type) { + case MachO::X86_64_RELOC_UNSIGNED: + if (!RI.r_pcrel && RI.r_length == 3) + return RI.r_extern ? Pointer64 : Pointer64Anon; + break; + case MachO::X86_64_RELOC_SIGNED: + if (RI.r_pcrel && RI.r_length == 2) + return RI.r_extern ? PCRel32 : PCRel32Anon; + break; + case MachO::X86_64_RELOC_BRANCH: + if (RI.r_pcrel && RI.r_extern && RI.r_length == 2) + return Branch32; + break; + case MachO::X86_64_RELOC_GOT_LOAD: + if (RI.r_pcrel && RI.r_extern && RI.r_length == 2) + return PCRel32GOTLoad; + break; + case MachO::X86_64_RELOC_GOT: + if (RI.r_pcrel && RI.r_extern && RI.r_length == 2) + return PCRel32GOT; + break; + case MachO::X86_64_RELOC_SUBTRACTOR: + // SUBTRACTOR must be non-pc-rel, extern, with length 2 or 3. + // Initially represent SUBTRACTOR relocations with 'Delta<W>'. They may + // be turned into NegDelta<W> by parsePairRelocation. + if (!RI.r_pcrel && RI.r_extern) { + if (RI.r_length == 2) + return Delta32; + else if (RI.r_length == 3) + return Delta64; + } + break; + case MachO::X86_64_RELOC_SIGNED_1: + if (RI.r_pcrel && RI.r_length == 2) + return RI.r_extern ? PCRel32Minus1 : PCRel32Minus1Anon; + break; + case MachO::X86_64_RELOC_SIGNED_2: + if (RI.r_pcrel && RI.r_length == 2) + return RI.r_extern ? PCRel32Minus2 : PCRel32Minus2Anon; + break; + case MachO::X86_64_RELOC_SIGNED_4: + if (RI.r_pcrel && RI.r_length == 2) + return RI.r_extern ? PCRel32Minus4 : PCRel32Minus4Anon; + break; + case MachO::X86_64_RELOC_TLV: + if (RI.r_pcrel && RI.r_extern && RI.r_length == 2) + return PCRel32TLV; + 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)); + } + + Expected<Atom &> findAtomBySymbolIndex(const MachO::relocation_info &RI) { + auto &Obj = getObject(); + if (RI.r_symbolnum >= NumSymbols) + return make_error<JITLinkError>("Symbol index out of range"); + auto SymI = Obj.getSymbolByIndex(RI.r_symbolnum); + auto Name = SymI->getName(); + if (!Name) + return Name.takeError(); + return getGraph().getAtomByName(*Name); + } + + MachO::relocation_info + getRelocationInfo(const object::relocation_iterator RelItr) { + MachO::any_relocation_info ARI = + getObject().getRelocation(RelItr->getRawDataRefImpl()); + MachO::relocation_info RI; + memcpy(&RI, &ARI, sizeof(MachO::relocation_info)); + return RI; + } + + using PairRelocInfo = std::tuple<MachOX86RelocationKind, Atom *, uint64_t>; + + // Parses paired SUBTRACTOR/UNSIGNED relocations and, on success, + // returns the edge kind and addend to be used. + Expected<PairRelocInfo> + parsePairRelocation(DefinedAtom &AtomToFix, Edge::Kind SubtractorKind, + const MachO::relocation_info &SubRI, + JITTargetAddress FixupAddress, const char *FixupContent, + object::relocation_iterator &UnsignedRelItr, + object::relocation_iterator &RelEnd) { + using namespace support; + + assert(((SubtractorKind == Delta32 && SubRI.r_length == 2) || + (SubtractorKind == Delta64 && 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"); + + auto FromAtom = findAtomBySymbolIndex(SubRI); + if (!FromAtom) + return FromAtom.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 'ToAtom' using symbol number or address, depending on whether the + // paired UNSIGNED relocation is extern. + Atom *ToAtom = nullptr; + if (UnsignedRI.r_extern) { + // Find target atom by symbol index. + if (auto ToAtomOrErr = findAtomBySymbolIndex(UnsignedRI)) + ToAtom = &*ToAtomOrErr; + else + return ToAtomOrErr.takeError(); + } else { + if (auto ToAtomOrErr = getGraph().findAtomByAddress(FixupValue)) + ToAtom = &*ToAtomOrErr; + else + return ToAtomOrErr.takeError(); + FixupValue -= ToAtom->getAddress(); + } + + MachOX86RelocationKind DeltaKind; + Atom *TargetAtom; + uint64_t Addend; + if (areLayoutLocked(AtomToFix, *FromAtom)) { + TargetAtom = ToAtom; + DeltaKind = (SubRI.r_length == 3) ? Delta64 : Delta32; + Addend = FixupValue + (FixupAddress - FromAtom->getAddress()); + // FIXME: handle extern 'from'. + } else if (areLayoutLocked(AtomToFix, *ToAtom)) { + TargetAtom = &*FromAtom; + DeltaKind = (SubRI.r_length == 3) ? NegDelta64 : NegDelta32; + Addend = FixupValue - (FixupAddress - ToAtom->getAddress()); + } else { + // AtomToFix was neither FromAtom nor ToAtom. + return make_error<JITLinkError>("SUBTRACTOR relocation must fix up " + "either 'A' or 'B' (or an atom in one " + "of their alt-entry groups)"); + } + + return PairRelocInfo(DeltaKind, TargetAtom, Addend); + } + + Error addRelocations() override { + using namespace support; + auto &G = getGraph(); + auto &Obj = getObject(); + + for (auto &S : Obj.sections()) { + + JITTargetAddress SectionAddress = S.getAddress(); + + for (auto RelItr = S.relocation_begin(), RelEnd = S.relocation_end(); + RelItr != RelEnd; ++RelItr) { + + MachO::relocation_info RI = getRelocationInfo(RelItr); + + // Sanity check the relocation kind. + auto Kind = getRelocationKind(RI); + if (!Kind) + return Kind.takeError(); + + // Find the address of the value to fix up. + JITTargetAddress FixupAddress = SectionAddress + (uint32_t)RI.r_address; + + LLVM_DEBUG({ + dbgs() << "Processing relocation at " + << format("0x%016" PRIx64, FixupAddress) << "\n"; + }); + + // Find the atom that the fixup points to. + DefinedAtom *AtomToFix = nullptr; + { + auto AtomToFixOrErr = G.findAtomByAddress(FixupAddress); + if (!AtomToFixOrErr) + return AtomToFixOrErr.takeError(); + AtomToFix = &*AtomToFixOrErr; + } + + if (FixupAddress + static_cast<JITTargetAddress>(1ULL << RI.r_length) > + AtomToFix->getAddress() + AtomToFix->getContent().size()) + return make_error<JITLinkError>( + "Relocation content extends past end of fixup atom"); + + // Get a pointer to the fixup content. + const char *FixupContent = AtomToFix->getContent().data() + + (FixupAddress - AtomToFix->getAddress()); + + // The target atom and addend will be populated by the switch below. + Atom *TargetAtom = nullptr; + uint64_t Addend = 0; + + switch (*Kind) { + case Branch32: + case PCRel32: + case PCRel32GOTLoad: + case PCRel32GOT: + if (auto TargetAtomOrErr = findAtomBySymbolIndex(RI)) + TargetAtom = &*TargetAtomOrErr; + else + return TargetAtomOrErr.takeError(); + Addend = *(const ulittle32_t *)FixupContent; + break; + case Pointer64: + if (auto TargetAtomOrErr = findAtomBySymbolIndex(RI)) + TargetAtom = &*TargetAtomOrErr; + else + return TargetAtomOrErr.takeError(); + Addend = *(const ulittle64_t *)FixupContent; + break; + case Pointer64Anon: { + JITTargetAddress TargetAddress = *(const ulittle64_t *)FixupContent; + if (auto TargetAtomOrErr = G.findAtomByAddress(TargetAddress)) + TargetAtom = &*TargetAtomOrErr; + else + return TargetAtomOrErr.takeError(); + Addend = TargetAddress - TargetAtom->getAddress(); + break; + } + case PCRel32Minus1: + case PCRel32Minus2: + case PCRel32Minus4: + if (auto TargetAtomOrErr = findAtomBySymbolIndex(RI)) + TargetAtom = &*TargetAtomOrErr; + else + return TargetAtomOrErr.takeError(); + Addend = *(const ulittle32_t *)FixupContent + + (1 << (*Kind - PCRel32Minus1)); + break; + case PCRel32Anon: { + JITTargetAddress TargetAddress = + FixupAddress + 4 + *(const ulittle32_t *)FixupContent; + if (auto TargetAtomOrErr = G.findAtomByAddress(TargetAddress)) + TargetAtom = &*TargetAtomOrErr; + else + return TargetAtomOrErr.takeError(); + Addend = TargetAddress - TargetAtom->getAddress(); + break; + } + case PCRel32Minus1Anon: + case PCRel32Minus2Anon: + case PCRel32Minus4Anon: { + JITTargetAddress Delta = + static_cast<JITTargetAddress>(1ULL << (*Kind - PCRel32Minus1Anon)); + JITTargetAddress TargetAddress = + FixupAddress + 4 + Delta + *(const ulittle32_t *)FixupContent; + if (auto TargetAtomOrErr = G.findAtomByAddress(TargetAddress)) + TargetAtom = &*TargetAtomOrErr; + else + return TargetAtomOrErr.takeError(); + Addend = TargetAddress - TargetAtom->getAddress(); + break; + } + case Delta32: + case Delta64: { + // 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(*AtomToFix, *Kind, RI, FixupAddress, + FixupContent, ++RelItr, RelEnd); + if (!PairInfo) + return PairInfo.takeError(); + std::tie(*Kind, TargetAtom, Addend) = *PairInfo; + assert(TargetAtom && "No target atom from parsePairRelocation?"); + break; + } + default: + llvm_unreachable("Special relocation kind should not appear in " + "mach-o file"); + } + + LLVM_DEBUG({ + Edge GE(*Kind, FixupAddress - AtomToFix->getAddress(), *TargetAtom, + Addend); + printEdge(dbgs(), *AtomToFix, GE, + getMachOX86RelocationKindName(*Kind)); + dbgs() << "\n"; + }); + AtomToFix->addEdge(*Kind, FixupAddress - AtomToFix->getAddress(), + *TargetAtom, Addend); + } + } + return Error::success(); + } + + unsigned NumSymbols = 0; +}; + +class MachO_x86_64_GOTAndStubsBuilder + : public BasicGOTAndStubsBuilder<MachO_x86_64_GOTAndStubsBuilder> { +public: + MachO_x86_64_GOTAndStubsBuilder(AtomGraph &G) + : BasicGOTAndStubsBuilder<MachO_x86_64_GOTAndStubsBuilder>(G) {} + + bool isGOTEdge(Edge &E) const { + return E.getKind() == PCRel32GOT || E.getKind() == PCRel32GOTLoad; + } + + DefinedAtom &createGOTEntry(Atom &Target) { + auto &GOTEntryAtom = G.addAnonymousAtom(getGOTSection(), 0x0, 8); + GOTEntryAtom.setContent( + StringRef(reinterpret_cast<const char *>(NullGOTEntryContent), 8)); + GOTEntryAtom.addEdge(Pointer64, 0, Target, 0); + return GOTEntryAtom; + } + + void fixGOTEdge(Edge &E, Atom &GOTEntry) { + assert((E.getKind() == PCRel32GOT || E.getKind() == PCRel32GOTLoad) && + "Not a GOT edge?"); + E.setKind(PCRel32); + E.setTarget(GOTEntry); + // Leave the edge addend as-is. + } + + bool isExternalBranchEdge(Edge &E) { + return E.getKind() == Branch32 && !E.getTarget().isDefined(); + } + + DefinedAtom &createStub(Atom &Target) { + auto &StubAtom = G.addAnonymousAtom(getStubsSection(), 0x0, 2); + StubAtom.setContent( + StringRef(reinterpret_cast<const char *>(StubContent), 6)); + + // Re-use GOT entries for stub targets. + auto &GOTEntryAtom = getGOTEntryAtom(Target); + StubAtom.addEdge(PCRel32, 2, GOTEntryAtom, 0); + + return StubAtom; + } + + void fixExternalBranchEdge(Edge &E, Atom &Stub) { + assert(E.getKind() == Branch32 && "Not a Branch32 edge?"); + assert(E.getAddend() == 0 && "Branch32 edge has non-zero addend?"); + E.setTarget(Stub); + } + +private: + Section &getGOTSection() { + if (!GOTSection) + GOTSection = &G.createSection("$__GOT", 8, sys::Memory::MF_READ, false); + return *GOTSection; + } + + Section &getStubsSection() { + if (!StubsSection) { + auto StubsProt = static_cast<sys::Memory::ProtectionFlags>( + sys::Memory::MF_READ | sys::Memory::MF_EXEC); + StubsSection = &G.createSection("$__STUBS", 8, StubsProt, false); + } + return *StubsSection; + } + + static const uint8_t NullGOTEntryContent[8]; + static const uint8_t StubContent[6]; + Section *GOTSection = nullptr; + Section *StubsSection = nullptr; +}; + +const uint8_t MachO_x86_64_GOTAndStubsBuilder::NullGOTEntryContent[8] = { + 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00}; +const uint8_t MachO_x86_64_GOTAndStubsBuilder::StubContent[6] = { + 0xFF, 0x25, 0x00, 0x00, 0x00, 0x00}; +} // namespace + +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, + PassConfiguration PassConfig) + : JITLinker(std::move(Ctx), std::move(PassConfig)) {} + +private: + StringRef getEdgeKindName(Edge::Kind R) const override { + return getMachOX86RelocationKindName(R); + } + + Expected<std::unique_ptr<AtomGraph>> + buildGraph(MemoryBufferRef ObjBuffer) override { + auto MachOObj = object::ObjectFile::createMachOObjectFile(ObjBuffer); + if (!MachOObj) + return MachOObj.takeError(); + return MachOAtomGraphBuilder_x86_64(**MachOObj).buildGraph(); + } + + static Error targetOutOfRangeError(const Atom &A, const Edge &E) { + std::string ErrMsg; + { + raw_string_ostream ErrStream(ErrMsg); + ErrStream << "Relocation target out of range: "; + printEdge(ErrStream, A, E, getMachOX86RelocationKindName(E.getKind())); + ErrStream << "\n"; + } + return make_error<JITLinkError>(std::move(ErrMsg)); + } + + Error applyFixup(DefinedAtom &A, const Edge &E, char *AtomWorkingMem) const { + using namespace support; + + char *FixupPtr = AtomWorkingMem + E.getOffset(); + JITTargetAddress FixupAddress = A.getAddress() + E.getOffset(); + + switch (E.getKind()) { + case Branch32: + case PCRel32: + case PCRel32Anon: { + int64_t Value = + E.getTarget().getAddress() - (FixupAddress + 4) + E.getAddend(); + if (Value < std::numeric_limits<int32_t>::min() || + Value > std::numeric_limits<int32_t>::max()) + return targetOutOfRangeError(A, E); + *(little32_t *)FixupPtr = Value; + break; + } + case Pointer64: + case Pointer64Anon: { + uint64_t Value = E.getTarget().getAddress() + E.getAddend(); + *(ulittle64_t *)FixupPtr = Value; + break; + } + case PCRel32Minus1: + case PCRel32Minus2: + case PCRel32Minus4: { + int Delta = 4 + (1 << (E.getKind() - PCRel32Minus1)); + int64_t Value = + E.getTarget().getAddress() - (FixupAddress + Delta) + E.getAddend(); + if (Value < std::numeric_limits<int32_t>::min() || + Value > std::numeric_limits<int32_t>::max()) + return targetOutOfRangeError(A, E); + *(little32_t *)FixupPtr = Value; + break; + } + case PCRel32Minus1Anon: + case PCRel32Minus2Anon: + case PCRel32Minus4Anon: { + int Delta = 4 + (1 << (E.getKind() - PCRel32Minus1Anon)); + int64_t Value = + E.getTarget().getAddress() - (FixupAddress + Delta) + E.getAddend(); + if (Value < std::numeric_limits<int32_t>::min() || + Value > std::numeric_limits<int32_t>::max()) + return targetOutOfRangeError(A, E); + *(little32_t *)FixupPtr = Value; + break; + } + case Delta32: + case Delta64: + case NegDelta32: + case NegDelta64: { + int64_t Value; + if (E.getKind() == Delta32 || E.getKind() == Delta64) + Value = E.getTarget().getAddress() - FixupAddress + E.getAddend(); + else + Value = FixupAddress - E.getTarget().getAddress() + E.getAddend(); + + if (E.getKind() == Delta32 || E.getKind() == NegDelta32) { + if (Value < std::numeric_limits<int32_t>::min() || + Value > std::numeric_limits<int32_t>::max()) + return targetOutOfRangeError(A, E); + *(little32_t *)FixupPtr = Value; + } else + *(little64_t *)FixupPtr = Value; + break; + } + default: + llvm_unreachable("Unrecognized edge kind"); + } + + return Error::success(); + } + + uint64_t NullValue = 0; +}; + +void jitLink_MachO_x86_64(std::unique_ptr<JITLinkContext> Ctx) { + PassConfiguration Config; + Triple TT("x86_64-apple-macosx"); + + if (Ctx->shouldAddDefaultTargetPasses(TT)) { + // Add a mark-live pass. + if (auto MarkLive = Ctx->getMarkLivePass(TT)) + Config.PrePrunePasses.push_back(std::move(MarkLive)); + else + Config.PrePrunePasses.push_back(markAllAtomsLive); + + // Add an in-place GOT/Stubs pass. + Config.PostPrunePasses.push_back([](AtomGraph &G) -> Error { + MachO_x86_64_GOTAndStubsBuilder(G).run(); + return Error::success(); + }); + } + + if (auto Err = Ctx->modifyPassConfig(TT, Config)) + return Ctx->notifyFailed(std::move(Err)); + + // Construct a JITLinker and run the link function. + MachOJITLinker_x86_64::link(std::move(Ctx), std::move(Config)); +} + +StringRef getMachOX86RelocationKindName(Edge::Kind R) { + switch (R) { + case Branch32: + return "Branch32"; + case Pointer64: + return "Pointer64"; + case Pointer64Anon: + return "Pointer64Anon"; + case PCRel32: + return "PCRel32"; + case PCRel32Minus1: + return "PCRel32Minus1"; + case PCRel32Minus2: + return "PCRel32Minus2"; + case PCRel32Minus4: + return "PCRel32Minus4"; + case PCRel32Anon: + return "PCRel32Anon"; + case PCRel32Minus1Anon: + return "PCRel32Minus1Anon"; + case PCRel32Minus2Anon: + return "PCRel32Minus2Anon"; + case PCRel32Minus4Anon: + return "PCRel32Minus4Anon"; + case PCRel32GOTLoad: + return "PCRel32GOTLoad"; + case PCRel32GOT: + return "PCRel32GOT"; + case PCRel32TLV: + return "PCRel32TLV"; + case Delta32: + return "Delta32"; + case Delta64: + return "Delta64"; + case NegDelta32: + return "NegDelta32"; + case NegDelta64: + return "NegDelta64"; + default: + return getGenericEdgeKindName(static_cast<Edge::Kind>(R)); + } +} + +} // end namespace jitlink +} // end namespace llvm |