1 //= AArch64WinCOFFObjectWriter.cpp - AArch64 Windows COFF Object Writer C++ =//
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 #include "MCTargetDesc/AArch64FixupKinds.h"
10 #include "MCTargetDesc/AArch64MCExpr.h"
11 #include "llvm/ADT/Twine.h"
12 #include "llvm/BinaryFormat/COFF.h"
13 #include "llvm/MC/MCAsmBackend.h"
14 #include "llvm/MC/MCContext.h"
15 #include "llvm/MC/MCExpr.h"
16 #include "llvm/MC/MCFixup.h"
17 #include "llvm/MC/MCFixupKindInfo.h"
18 #include "llvm/MC/MCObjectWriter.h"
19 #include "llvm/MC/MCValue.h"
20 #include "llvm/MC/MCWinCOFFObjectWriter.h"
21 #include "llvm/Support/ErrorHandling.h"
22 #include "llvm/Support/raw_ostream.h"
23 #include <cassert>
24 
25 using namespace llvm;
26 
27 namespace {
28 
29 class AArch64WinCOFFObjectWriter : public MCWinCOFFObjectTargetWriter {
30 public:
31   AArch64WinCOFFObjectWriter()
32       : MCWinCOFFObjectTargetWriter(COFF::IMAGE_FILE_MACHINE_ARM64) {}
33 
34   ~AArch64WinCOFFObjectWriter() override = default;
35 
36   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
37                         const MCFixup &Fixup, bool IsCrossSection,
38                         const MCAsmBackend &MAB) const override;
39 
40   bool recordRelocation(const MCFixup &) const override;
41 };
42 
43 } // end anonymous namespace
44 
45 unsigned AArch64WinCOFFObjectWriter::getRelocType(
46     MCContext &Ctx, const MCValue &Target, const MCFixup &Fixup,
47     bool IsCrossSection, const MCAsmBackend &MAB) const {
48   auto Modifier = Target.isAbsolute() ? MCSymbolRefExpr::VK_None
49                                       : Target.getSymA()->getKind();
50   const MCExpr *Expr = Fixup.getValue();
51 
52   if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
53     AArch64MCExpr::VariantKind RefKind = A64E->getKind();
54     switch (AArch64MCExpr::getSymbolLoc(RefKind)) {
55     case AArch64MCExpr::VK_ABS:
56     case AArch64MCExpr::VK_SECREL:
57       // Supported
58       break;
59     default:
60       Ctx.reportError(Fixup.getLoc(), "relocation variant " +
61                                           A64E->getVariantKindName() +
62                                           " unsupported on COFF targets");
63       return COFF::IMAGE_REL_ARM64_ABSOLUTE; // Dummy return value
64     }
65   }
66 
67   switch (static_cast<unsigned>(Fixup.getKind())) {
68   default: {
69     if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
70       Ctx.reportError(Fixup.getLoc(), "relocation type " +
71                                           A64E->getVariantKindName() +
72                                           " unsupported on COFF targets");
73     } else {
74       const MCFixupKindInfo &Info = MAB.getFixupKindInfo(Fixup.getKind());
75       Ctx.reportError(Fixup.getLoc(), Twine("relocation type ") + Info.Name +
76                                           " unsupported on COFF targets");
77     }
78     return COFF::IMAGE_REL_ARM64_ABSOLUTE; // Dummy return value
79   }
80 
81   case FK_Data_4:
82     switch (Modifier) {
83     default:
84       return COFF::IMAGE_REL_ARM64_ADDR32;
85     case MCSymbolRefExpr::VK_COFF_IMGREL32:
86       return COFF::IMAGE_REL_ARM64_ADDR32NB;
87     case MCSymbolRefExpr::VK_SECREL:
88       return COFF::IMAGE_REL_ARM64_SECREL;
89     }
90 
91   case FK_Data_8:
92     return COFF::IMAGE_REL_ARM64_ADDR64;
93 
94   case FK_SecRel_2:
95     return COFF::IMAGE_REL_ARM64_SECTION;
96 
97   case FK_SecRel_4:
98     return COFF::IMAGE_REL_ARM64_SECREL;
99 
100   case AArch64::fixup_aarch64_add_imm12:
101     if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
102       AArch64MCExpr::VariantKind RefKind = A64E->getKind();
103       if (RefKind == AArch64MCExpr::VK_SECREL_LO12)
104         return COFF::IMAGE_REL_ARM64_SECREL_LOW12A;
105       if (RefKind == AArch64MCExpr::VK_SECREL_HI12)
106         return COFF::IMAGE_REL_ARM64_SECREL_HIGH12A;
107     }
108     return COFF::IMAGE_REL_ARM64_PAGEOFFSET_12A;
109 
110   case AArch64::fixup_aarch64_ldst_imm12_scale1:
111   case AArch64::fixup_aarch64_ldst_imm12_scale2:
112   case AArch64::fixup_aarch64_ldst_imm12_scale4:
113   case AArch64::fixup_aarch64_ldst_imm12_scale8:
114   case AArch64::fixup_aarch64_ldst_imm12_scale16:
115     if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
116       AArch64MCExpr::VariantKind RefKind = A64E->getKind();
117       if (RefKind == AArch64MCExpr::VK_SECREL_LO12)
118         return COFF::IMAGE_REL_ARM64_SECREL_LOW12L;
119     }
120     return COFF::IMAGE_REL_ARM64_PAGEOFFSET_12L;
121 
122   case AArch64::fixup_aarch64_pcrel_adr_imm21:
123     return COFF::IMAGE_REL_ARM64_REL21;
124 
125   case AArch64::fixup_aarch64_pcrel_adrp_imm21:
126     return COFF::IMAGE_REL_ARM64_PAGEBASE_REL21;
127 
128   case AArch64::fixup_aarch64_pcrel_branch14:
129     return COFF::IMAGE_REL_ARM64_BRANCH14;
130 
131   case AArch64::fixup_aarch64_pcrel_branch19:
132     return COFF::IMAGE_REL_ARM64_BRANCH19;
133 
134   case AArch64::fixup_aarch64_pcrel_branch26:
135   case AArch64::fixup_aarch64_pcrel_call26:
136     return COFF::IMAGE_REL_ARM64_BRANCH26;
137   }
138 }
139 
140 bool AArch64WinCOFFObjectWriter::recordRelocation(const MCFixup &Fixup) const {
141   return true;
142 }
143 
144 namespace llvm {
145 
146 std::unique_ptr<MCObjectTargetWriter> createAArch64WinCOFFObjectWriter() {
147   return std::make_unique<AArch64WinCOFFObjectWriter>();
148 }
149 
150 } // end namespace llvm
151