llvm/lib/ExecutionEngine/JITLink/ELF.cpp

   1 //===-------------- ELF.cpp - JIT linker function for ELF -------------===//
   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-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8 //
   9 // ELF jit-link function.
  10 //
  11 //===----------------------------------------------------------------------===//
  12
  13 #include "llvm/ExecutionEngine/JITLink/ELF.h"
  14
  15 #include "llvm/BinaryFormat/ELF.h"
  16 #include "llvm/ExecutionEngine/JITLink/ELF_riscv.h"
  17 #include "llvm/ExecutionEngine/JITLink/ELF_x86_64.h"
  18 #include "llvm/Object/ELF.h"
  19 #include "llvm/Support/Endian.h"
  20 #include "llvm/Support/Format.h"
  21 #include "llvm/Support/MemoryBuffer.h"
  22 #include <cstring>
  23
  24 using namespace llvm;
  25
  26 #define DEBUG_TYPE "jitlink"
  27
  28 namespace llvm {
  29 namespace jitlink {
  30
  31 Expected<uint16_t> readTargetMachineArch(StringRef Buffer) {
  32   const char *Data = Buffer.data();
  33
  34   if (Data[ELF::EI_DATA] == ELF::ELFDATA2LSB) {
  35     if (Data[ELF::EI_CLASS] == ELF::ELFCLASS64) {
  36       if (auto File = llvm::object::ELF64LEFile::create(Buffer)) {
  37         return File->getHeader().e_machine;
  38       } else {
  39         return File.takeError();
  40       }
  41     } else if (Data[ELF::EI_CLASS] == ELF::ELFCLASS32) {
  42       if (auto File = llvm::object::ELF32LEFile::create(Buffer)) {
  43         return File->getHeader().e_machine;
  44       } else {
  45         return File.takeError();
  46       }
  47     }
  48   }
  49
  50   return ELF::EM_NONE;
  51 }
  52
  53 Expected<std::unique_ptr<LinkGraph>>
  54 createLinkGraphFromELFObject(MemoryBufferRef ObjectBuffer) {
  55   StringRef Buffer = ObjectBuffer.getBuffer();
  56   if (Buffer.size() < ELF::EI_MAG3 + 1)
  57     return make_error<JITLinkError>("Truncated ELF buffer");
  58
  59   if (memcmp(Buffer.data(), ELF::ElfMagic, strlen(ELF::ElfMagic)) != 0)
  60     return make_error<JITLinkError>("ELF magic not valid");
  61
  62   Expected<uint16_t> TargetMachineArch = readTargetMachineArch(Buffer);
  63   if (!TargetMachineArch)
  64     return TargetMachineArch.takeError();
  65
  66   switch (*TargetMachineArch) {
  67   case ELF::EM_RISCV:
  68     return createLinkGraphFromELFObject_riscv(ObjectBuffer);
  69   case ELF::EM_X86_64:
  70     return createLinkGraphFromELFObject_x86_64(ObjectBuffer);
  71   default:
  72     return make_error<JITLinkError>(
  73         "Unsupported target machine architecture in ELF object " +
  74         ObjectBuffer.getBufferIdentifier());
  75   }
  76 }
  77
  78 void link_ELF(std::unique_ptr<LinkGraph> G,
  79               std::unique_ptr<JITLinkContext> Ctx) {
  80   switch (G->getTargetTriple().getArch()) {
  81   case Triple::riscv32:
  82   case Triple::riscv64:
  83     link_ELF_riscv(std::move(G), std::move(Ctx));
  84     return;
  85   case Triple::x86_64:
  86     link_ELF_x86_64(std::move(G), std::move(Ctx));
  87     return;
  88   default:
  89     Ctx->notifyFailed(make_error<JITLinkError>(
  90         "Unsupported target machine architecture in ELF link graph " +
  91         G->getName()));
  92     return;
  93   }
  94 }
  95
  96 } // end namespace jitlink
  97 } // end namespace llvm