1 //===-------------- COFF.cpp - JIT linker function for COFF -------------===//
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 // COFF jit-link function.
10 //
11 //===----------------------------------------------------------------------===//
12
13 #include "llvm/ExecutionEngine/JITLink/COFF.h"
14
15 #include "llvm/BinaryFormat/COFF.h"
16 #include "llvm/ExecutionEngine/JITLink/COFF_x86_64.h"
17 #include "llvm/Object/COFF.h"
18 #include "llvm/Support/Endian.h"
19 #include "llvm/Support/Format.h"
20 #include "llvm/Support/MemoryBuffer.h"
21 #include <cstring>
22
23 using namespace llvm;
24
25 #define DEBUG_TYPE "jitlink"
26
27 namespace llvm {
28 namespace jitlink {
29
getMachineName(uint16_t Machine)30 static StringRef getMachineName(uint16_t Machine) {
31 switch (Machine) {
32 case COFF::IMAGE_FILE_MACHINE_I386:
33 return "i386";
34 case COFF::IMAGE_FILE_MACHINE_AMD64:
35 return "x86_64";
36 case COFF::IMAGE_FILE_MACHINE_ARMNT:
37 return "ARM";
38 case COFF::IMAGE_FILE_MACHINE_ARM64:
39 return "ARM64";
40 default:
41 return "unknown";
42 }
43 }
44
45 Expected<std::unique_ptr<LinkGraph>>
createLinkGraphFromCOFFObject(MemoryBufferRef ObjectBuffer)46 createLinkGraphFromCOFFObject(MemoryBufferRef ObjectBuffer) {
47 StringRef Data = ObjectBuffer.getBuffer();
48
49 // Check magic
50 auto Magic = identify_magic(ObjectBuffer.getBuffer());
51 if (Magic != file_magic::coff_object)
52 return make_error<JITLinkError>("Invalid COFF buffer");
53
54 if (Data.size() < sizeof(object::coff_file_header))
55 return make_error<JITLinkError>("Truncated COFF buffer");
56
57 uint64_t CurPtr = 0;
58 bool IsPE = false;
59
60 // Check if this is a PE/COFF file.
61 if (Data.size() >= sizeof(object::dos_header) + sizeof(COFF::PEMagic)) {
62 const auto *DH =
63 reinterpret_cast<const object::dos_header *>(Data.data() + CurPtr);
64 if (DH->Magic[0] == 'M' && DH->Magic[1] == 'Z') {
65 // Check the PE magic bytes. ("PE\0\0")
66 CurPtr = DH->AddressOfNewExeHeader;
67 if (memcmp(Data.data() + CurPtr, COFF::PEMagic, sizeof(COFF::PEMagic)) !=
68 0) {
69 return make_error<JITLinkError>("Incorrect PE magic");
70 }
71 CurPtr += sizeof(COFF::PEMagic);
72 IsPE = true;
73 }
74 }
75 if (Data.size() < CurPtr + sizeof(object::coff_file_header))
76 return make_error<JITLinkError>("Truncated COFF buffer");
77
78 const object::coff_file_header *COFFHeader =
79 reinterpret_cast<const object::coff_file_header *>(Data.data() + CurPtr);
80 const object::coff_bigobj_file_header *COFFBigObjHeader = nullptr;
81
82 // Deal with bigobj file
83 if (!IsPE && COFFHeader->Machine == COFF::IMAGE_FILE_MACHINE_UNKNOWN &&
84 COFFHeader->NumberOfSections == uint16_t(0xffff) &&
85 Data.size() >= sizeof(object::coff_bigobj_file_header)) {
86 if (Data.size() < sizeof(object::coff_file_header)) {
87 return make_error<JITLinkError>("Truncated COFF buffer");
88 }
89 COFFBigObjHeader =
90 reinterpret_cast<const object::coff_bigobj_file_header *>(Data.data() +
91 CurPtr);
92
93 // Verify that we are dealing with bigobj.
94 if (COFFBigObjHeader->Version >= COFF::BigObjHeader::MinBigObjectVersion &&
95 std::memcmp(COFFBigObjHeader->UUID, COFF::BigObjMagic,
96 sizeof(COFF::BigObjMagic)) == 0) {
97 COFFHeader = nullptr;
98 CurPtr += sizeof(object::coff_bigobj_file_header);
99 } else
100 COFFBigObjHeader = nullptr;
101 }
102
103 uint16_t Machine =
104 COFFHeader ? COFFHeader->Machine : COFFBigObjHeader->Machine;
105 LLVM_DEBUG({
106 dbgs() << "jitLink_COFF: PE = " << (IsPE ? "yes" : "no")
107 << ", bigobj = " << (COFFBigObjHeader ? "yes" : "no")
108 << ", identifier = \"" << ObjectBuffer.getBufferIdentifier() << "\" "
109 << "machine = " << getMachineName(Machine) << "\n";
110 });
111
112 switch (Machine) {
113 case COFF::IMAGE_FILE_MACHINE_AMD64:
114 return createLinkGraphFromCOFFObject_x86_64(ObjectBuffer);
115 default:
116 return make_error<JITLinkError>(
117 "Unsupported target machine architecture in COFF object " +
118 ObjectBuffer.getBufferIdentifier() + ": " + getMachineName(Machine));
119 }
120 }
121
link_COFF(std::unique_ptr<LinkGraph> G,std::unique_ptr<JITLinkContext> Ctx)122 void link_COFF(std::unique_ptr<LinkGraph> G,
123 std::unique_ptr<JITLinkContext> Ctx) {
124 switch (G->getTargetTriple().getArch()) {
125 case Triple::x86_64:
126 link_COFF_x86_64(std::move(G), std::move(Ctx));
127 return;
128 default:
129 Ctx->notifyFailed(make_error<JITLinkError>(
130 "Unsupported target machine architecture in COFF link graph " +
131 G->getName()));
132 return;
133 }
134 }
135
136 } // end namespace jitlink
137 } // end namespace llvm
138