153 lines · cpp
1//===-------------- MachO.cpp - JIT linker function for MachO -------------===//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// MachO jit-link function.10//11//===----------------------------------------------------------------------===//12 13#include "llvm/ExecutionEngine/JITLink/MachO.h"14 15#include "llvm/BinaryFormat/MachO.h"16#include "llvm/ExecutionEngine/JITLink/MachO_arm64.h"17#include "llvm/ExecutionEngine/JITLink/MachO_x86_64.h"18#include "llvm/Support/Format.h"19 20using namespace llvm;21 22#define DEBUG_TYPE "jitlink"23 24namespace llvm {25namespace jitlink {26 27Expected<std::unique_ptr<LinkGraph>>28createLinkGraphFromMachOObject(MemoryBufferRef ObjectBuffer,29 std::shared_ptr<orc::SymbolStringPool> SSP) {30 StringRef Data = ObjectBuffer.getBuffer();31 if (Data.size() < 4)32 return make_error<JITLinkError>("Truncated MachO buffer \"" +33 ObjectBuffer.getBufferIdentifier() + "\"");34 35 uint32_t Magic;36 memcpy(&Magic, Data.data(), sizeof(uint32_t));37 LLVM_DEBUG({38 dbgs() << "jitLink_MachO: magic = " << format("0x%08" PRIx32, Magic)39 << ", identifier = \"" << ObjectBuffer.getBufferIdentifier()40 << "\"\n";41 });42 43 if (Magic == MachO::MH_MAGIC || Magic == MachO::MH_CIGAM)44 return make_error<JITLinkError>("MachO 32-bit platforms not supported");45 else if (Magic == MachO::MH_MAGIC_64 || Magic == MachO::MH_CIGAM_64) {46 47 if (Data.size() < sizeof(MachO::mach_header_64))48 return make_error<JITLinkError>("Truncated MachO buffer \"" +49 ObjectBuffer.getBufferIdentifier() +50 "\"");51 52 // Read the CPU type from the header.53 uint32_t CPUType;54 memcpy(&CPUType, Data.data() + 4, sizeof(uint32_t));55 if (Magic == MachO::MH_CIGAM_64)56 CPUType = llvm::byteswap<uint32_t>(CPUType);57 58 LLVM_DEBUG({59 dbgs() << "jitLink_MachO: cputype = " << format("0x%08" PRIx32, CPUType)60 << "\n";61 });62 63 switch (CPUType) {64 case MachO::CPU_TYPE_ARM64:65 return createLinkGraphFromMachOObject_arm64(ObjectBuffer, std::move(SSP));66 case MachO::CPU_TYPE_X86_64:67 return createLinkGraphFromMachOObject_x86_64(ObjectBuffer,68 std::move(SSP));69 }70 return make_error<JITLinkError>("MachO-64 CPU type not valid");71 } else72 return make_error<JITLinkError>("Unrecognized MachO magic value");73}74 75void link_MachO(std::unique_ptr<LinkGraph> G,76 std::unique_ptr<JITLinkContext> Ctx) {77 78 switch (G->getTargetTriple().getArch()) {79 case Triple::aarch64:80 return link_MachO_arm64(std::move(G), std::move(Ctx));81 case Triple::x86_64:82 return link_MachO_x86_64(std::move(G), std::move(Ctx));83 default:84 Ctx->notifyFailed(make_error<JITLinkError>("MachO-64 CPU type not valid"));85 return;86 }87}88 89template <typename MachOHeaderType>90static Expected<Block &> createLocalHeaderBlock(LinkGraph &G, Section &Sec) {91 auto &B = G.createMutableContentBlock(Sec, sizeof(MachOHeaderType),92 orc::ExecutorAddr(), 8, 0, true);93 MachOHeaderType Hdr;94 Hdr.magic = G.getPointerSize() == 4 ? MachO::MH_MAGIC : MachO::MH_MAGIC_64;95 if (auto CPUType = MachO::getCPUType(G.getTargetTriple()))96 Hdr.cputype = *CPUType;97 else98 return CPUType.takeError();99 if (auto CPUSubType = MachO::getCPUSubType(G.getTargetTriple()))100 Hdr.cpusubtype = *CPUSubType;101 else102 return CPUSubType.takeError();103 Hdr.filetype = MachO::MH_OBJECT;104 105 if (G.getEndianness() != endianness::native)106 MachO::swapStruct(Hdr);107 108 memcpy(B.getAlreadyMutableContent().data(), &Hdr, sizeof(Hdr));109 110 return B;111}112 113Expected<Symbol &> getOrCreateLocalMachOHeader(LinkGraph &G) {114 StringRef LocalHeaderSectionName("__TEXT,__lcl_macho_hdr");115 Section *Sec = G.findSectionByName(LocalHeaderSectionName);116 if (Sec) {117 assert(Sec->blocks_size() == 1 && "Unexpected number of blocks");118 assert(Sec->symbols_size() == 1 && "Unexpected number of symbols");119 auto &Sym = **Sec->symbols().begin();120 assert(Sym.getOffset() == 0 && "Symbol not at start of header block");121 return Sym;122 }123 124 // Create the local header section, move all other sections up in the125 // section ordering to ensure that it's laid out first.126 for (auto &Sec : G.sections())127 Sec.setOrdinal(Sec.getOrdinal() + 1);128 129 Sec = &G.createSection(LocalHeaderSectionName, orc::MemProt::Read);130 131 Sec->setOrdinal(0);132 133 Block *B = nullptr;134 switch (G.getTargetTriple().getArch()) {135 case Triple::aarch64:136 case Triple::x86_64:137 if (auto BOrErr = createLocalHeaderBlock<MachO::mach_header_64>(G, *Sec))138 B = &*BOrErr;139 else140 return BOrErr.takeError();141 break;142 default:143 return make_error<JITLinkError>("Cannot create local Mach-O header for " +144 G.getName() + ": unsupported triple " +145 G.getTargetTriple().str());146 }147 148 return G.addAnonymousSymbol(*B, 0, B->getSize(), false, false);149}150 151} // end namespace jitlink152} // end namespace llvm153