1 //===-- X86WinCOFFObjectWriter.cpp - X86 Win COFF Writer ------------------===//
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 #include "MCTargetDesc/X86FixupKinds.h"
11 #include "MCTargetDesc/X86MCTargetDesc.h"
12 #include "llvm/BinaryFormat/COFF.h"
13 #include "llvm/MC/MCContext.h"
14 #include "llvm/MC/MCExpr.h"
15 #include "llvm/MC/MCFixup.h"
16 #include "llvm/MC/MCValue.h"
17 #include "llvm/MC/MCWinCOFFObjectWriter.h"
18 #include "llvm/Support/ErrorHandling.h"
19 
20 using namespace llvm;
21 
22 namespace {
23 
24 class X86WinCOFFObjectWriter : public MCWinCOFFObjectTargetWriter {
25 public:
26   X86WinCOFFObjectWriter(bool Is64Bit);
27   ~X86WinCOFFObjectWriter() override = default;
28 
29   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
30                         const MCFixup &Fixup, bool IsCrossSection,
31                         const MCAsmBackend &MAB) const override;
32 };
33 
34 } // end anonymous namespace
35 
36 X86WinCOFFObjectWriter::X86WinCOFFObjectWriter(bool Is64Bit)
37     : MCWinCOFFObjectTargetWriter(Is64Bit ? COFF::IMAGE_FILE_MACHINE_AMD64
38                                           : COFF::IMAGE_FILE_MACHINE_I386) {}
39 
40 unsigned X86WinCOFFObjectWriter::getRelocType(MCContext &Ctx,
41                                               const MCValue &Target,
42                                               const MCFixup &Fixup,
43                                               bool IsCrossSection,
44                                               const MCAsmBackend &MAB) const {
45   unsigned FixupKind = Fixup.getKind();
46   if (IsCrossSection) {
47     if (FixupKind != FK_Data_4) {
48       Ctx.reportError(Fixup.getLoc(), "Cannot represent this expression");
49       return COFF::IMAGE_REL_AMD64_ADDR32;
50     }
51     FixupKind = FK_PCRel_4;
52   }
53 
54   MCSymbolRefExpr::VariantKind Modifier = Target.isAbsolute() ?
55     MCSymbolRefExpr::VK_None : Target.getSymA()->getKind();
56 
57   if (getMachine() == COFF::IMAGE_FILE_MACHINE_AMD64) {
58     switch (FixupKind) {
59     case FK_PCRel_4:
60     case X86::reloc_riprel_4byte:
61     case X86::reloc_riprel_4byte_movq_load:
62     case X86::reloc_riprel_4byte_relax:
63     case X86::reloc_riprel_4byte_relax_rex:
64       return COFF::IMAGE_REL_AMD64_REL32;
65     case FK_Data_4:
66     case X86::reloc_signed_4byte:
67     case X86::reloc_signed_4byte_relax:
68       if (Modifier == MCSymbolRefExpr::VK_COFF_IMGREL32)
69         return COFF::IMAGE_REL_AMD64_ADDR32NB;
70       if (Modifier == MCSymbolRefExpr::VK_SECREL)
71         return COFF::IMAGE_REL_AMD64_SECREL;
72       return COFF::IMAGE_REL_AMD64_ADDR32;
73     case FK_Data_8:
74       return COFF::IMAGE_REL_AMD64_ADDR64;
75     case FK_SecRel_2:
76       return COFF::IMAGE_REL_AMD64_SECTION;
77     case FK_SecRel_4:
78       return COFF::IMAGE_REL_AMD64_SECREL;
79     default:
80       llvm_unreachable("unsupported relocation type");
81     }
82   } else if (getMachine() == COFF::IMAGE_FILE_MACHINE_I386) {
83     switch (FixupKind) {
84     case FK_PCRel_4:
85     case X86::reloc_riprel_4byte:
86     case X86::reloc_riprel_4byte_movq_load:
87       return COFF::IMAGE_REL_I386_REL32;
88     case FK_Data_4:
89     case X86::reloc_signed_4byte:
90     case X86::reloc_signed_4byte_relax:
91       if (Modifier == MCSymbolRefExpr::VK_COFF_IMGREL32)
92         return COFF::IMAGE_REL_I386_DIR32NB;
93       if (Modifier == MCSymbolRefExpr::VK_SECREL)
94         return COFF::IMAGE_REL_AMD64_SECREL;
95       return COFF::IMAGE_REL_I386_DIR32;
96     case FK_SecRel_2:
97       return COFF::IMAGE_REL_I386_SECTION;
98     case FK_SecRel_4:
99       return COFF::IMAGE_REL_I386_SECREL;
100     default:
101       llvm_unreachable("unsupported relocation type");
102     }
103   } else
104     llvm_unreachable("Unsupported COFF machine type.");
105 }
106 
107 MCObjectWriter *llvm::createX86WinCOFFObjectWriter(raw_pwrite_stream &OS,
108                                                    bool Is64Bit) {
109   MCWinCOFFObjectTargetWriter *MOTW = new X86WinCOFFObjectWriter(Is64Bit);
110   return createWinCOFFObjectWriter(MOTW, OS);
111 }
112