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_aarch64.h"
17 #include "llvm/ExecutionEngine/JITLink/ELF_i386.h"
18 #include "llvm/ExecutionEngine/JITLink/ELF_loongarch.h"
19 #include "llvm/ExecutionEngine/JITLink/ELF_riscv.h"
20 #include "llvm/ExecutionEngine/JITLink/ELF_x86_64.h"
21 #include "llvm/Object/ELF.h"
22 #include "llvm/Support/Endian.h"
23 #include "llvm/Support/Format.h"
24 #include "llvm/Support/MemoryBuffer.h"
25 #include <cstring>
26 
27 using namespace llvm;
28 
29 #define DEBUG_TYPE "jitlink"
30 
31 namespace llvm {
32 namespace jitlink {
33 
34 Expected<uint16_t> readTargetMachineArch(StringRef Buffer) {
35   const char *Data = Buffer.data();
36 
37   if (Data[ELF::EI_DATA] == ELF::ELFDATA2LSB) {
38     if (Data[ELF::EI_CLASS] == ELF::ELFCLASS64) {
39       if (auto File = llvm::object::ELF64LEFile::create(Buffer)) {
40         return File->getHeader().e_machine;
41       } else {
42         return File.takeError();
43       }
44     } else if (Data[ELF::EI_CLASS] == ELF::ELFCLASS32) {
45       if (auto File = llvm::object::ELF32LEFile::create(Buffer)) {
46         return File->getHeader().e_machine;
47       } else {
48         return File.takeError();
49       }
50     }
51   }
52 
53   return ELF::EM_NONE;
54 }
55 
56 Expected<std::unique_ptr<LinkGraph>>
57 createLinkGraphFromELFObject(MemoryBufferRef ObjectBuffer) {
58   StringRef Buffer = ObjectBuffer.getBuffer();
59   if (Buffer.size() < ELF::EI_MAG3 + 1)
60     return make_error<JITLinkError>("Truncated ELF buffer");
61 
62   if (memcmp(Buffer.data(), ELF::ElfMagic, strlen(ELF::ElfMagic)) != 0)
63     return make_error<JITLinkError>("ELF magic not valid");
64 
65   Expected<uint16_t> TargetMachineArch = readTargetMachineArch(Buffer);
66   if (!TargetMachineArch)
67     return TargetMachineArch.takeError();
68 
69   switch (*TargetMachineArch) {
70   case ELF::EM_AARCH64:
71     return createLinkGraphFromELFObject_aarch64(ObjectBuffer);
72   case ELF::EM_LOONGARCH:
73     return createLinkGraphFromELFObject_loongarch(ObjectBuffer);
74   case ELF::EM_RISCV:
75     return createLinkGraphFromELFObject_riscv(ObjectBuffer);
76   case ELF::EM_X86_64:
77     return createLinkGraphFromELFObject_x86_64(ObjectBuffer);
78   case ELF::EM_386:
79     return createLinkGraphFromELFObject_i386(ObjectBuffer);
80   default:
81     return make_error<JITLinkError>(
82         "Unsupported target machine architecture in ELF object " +
83         ObjectBuffer.getBufferIdentifier());
84   }
85 }
86 
87 void link_ELF(std::unique_ptr<LinkGraph> G,
88               std::unique_ptr<JITLinkContext> Ctx) {
89   switch (G->getTargetTriple().getArch()) {
90   case Triple::aarch64:
91     link_ELF_aarch64(std::move(G), std::move(Ctx));
92     return;
93   case Triple::loongarch32:
94   case Triple::loongarch64:
95     link_ELF_loongarch(std::move(G), std::move(Ctx));
96     return;
97   case Triple::riscv32:
98   case Triple::riscv64:
99     link_ELF_riscv(std::move(G), std::move(Ctx));
100     return;
101   case Triple::x86_64:
102     link_ELF_x86_64(std::move(G), std::move(Ctx));
103     return;
104   case Triple::x86:
105     link_ELF_i386(std::move(G), std::move(Ctx));
106     return;
107   default:
108     Ctx->notifyFailed(make_error<JITLinkError>(
109         "Unsupported target machine architecture in ELF link graph " +
110         G->getName()));
111     return;
112   }
113 }
114 
115 } // end namespace jitlink
116 } // end namespace llvm
117