1 //===-------------- MachO.cpp - JIT linker function for MachO -------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // MachO jit-link function.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "llvm/ExecutionEngine/JITLink/MachO.h"
15 
16 #include "llvm/BinaryFormat/MachO.h"
17 #include "llvm/ExecutionEngine/JITLink/MachO_arm64.h"
18 #include "llvm/ExecutionEngine/JITLink/MachO_x86_64.h"
19 #include "llvm/Support/Format.h"
20 #include "llvm/Support/MemoryBuffer.h"
21 #include "llvm/Support/SwapByteOrder.h"
22 
23 using namespace llvm;
24 
25 #define DEBUG_TYPE "jitlink"
26 
27 namespace llvm {
28 namespace jitlink {
29 
jitLink_MachO(std::unique_ptr<JITLinkContext> Ctx)30 void jitLink_MachO(std::unique_ptr<JITLinkContext> Ctx) {
31 
32   // We don't want to do full MachO validation here. Just parse enough of the
33   // header to find out what MachO linker to use.
34 
35   StringRef Data = Ctx->getObjectBuffer().getBuffer();
36   if (Data.size() < 4) {
37     StringRef BufferName = Ctx->getObjectBuffer().getBufferIdentifier();
38     Ctx->notifyFailed(make_error<JITLinkError>("Truncated MachO buffer \"" +
39                                                BufferName + "\""));
40     return;
41   }
42 
43   uint32_t Magic;
44   memcpy(&Magic, Data.data(), sizeof(uint32_t));
45   LLVM_DEBUG({
46     dbgs() << "jitLink_MachO: magic = " << format("0x%08" PRIx32, Magic)
47            << ", identifier = \""
48            << Ctx->getObjectBuffer().getBufferIdentifier() << "\"\n";
49   });
50 
51   if (Magic == MachO::MH_MAGIC || Magic == MachO::MH_CIGAM) {
52     Ctx->notifyFailed(
53         make_error<JITLinkError>("MachO 32-bit platforms not supported"));
54     return;
55   } else if (Magic == MachO::MH_MAGIC_64 || Magic == MachO::MH_CIGAM_64) {
56 
57     if (Data.size() < sizeof(MachO::mach_header_64)) {
58       StringRef BufferName = Ctx->getObjectBuffer().getBufferIdentifier();
59       Ctx->notifyFailed(make_error<JITLinkError>("Truncated MachO buffer \"" +
60                                                  BufferName + "\""));
61       return;
62     }
63 
64     // Read the CPU type from the header.
65     uint32_t CPUType;
66     memcpy(&CPUType, Data.data() + 4, sizeof(uint32_t));
67     if (Magic == MachO::MH_CIGAM_64)
68       CPUType = ByteSwap_32(CPUType);
69 
70     LLVM_DEBUG({
71       dbgs() << "jitLink_MachO: cputype = " << format("0x%08" PRIx32, CPUType)
72              << "\n";
73     });
74 
75     switch (CPUType) {
76     case MachO::CPU_TYPE_ARM64:
77       return jitLink_MachO_arm64(std::move(Ctx));
78     case MachO::CPU_TYPE_X86_64:
79       return jitLink_MachO_x86_64(std::move(Ctx));
80     }
81     Ctx->notifyFailed(make_error<JITLinkError>("MachO-64 CPU type not valid"));
82     return;
83   }
84 
85   Ctx->notifyFailed(make_error<JITLinkError>("MachO magic not valid"));
86 }
87 
88 } // end namespace jitlink
89 } // end namespace llvm
90