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   unsigned FixupKind = Fixup.getKind();
49   if (IsCrossSection) {
50     if (FixupKind != FK_Data_4) {
51       Ctx.reportError(Fixup.getLoc(), "Cannot represent this expression");
52       return COFF::IMAGE_REL_ARM64_ADDR32;
53     }
54     FixupKind = FK_PCRel_4;
55   }
56 
57   auto Modifier = Target.isAbsolute() ? MCSymbolRefExpr::VK_None
58                                       : Target.getSymA()->getKind();
59   const MCExpr *Expr = Fixup.getValue();
60 
61   if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
62     AArch64MCExpr::VariantKind RefKind = A64E->getKind();
63     switch (AArch64MCExpr::getSymbolLoc(RefKind)) {
64     case AArch64MCExpr::VK_ABS:
65     case AArch64MCExpr::VK_SECREL:
66       // Supported
67       break;
68     default:
69       Ctx.reportError(Fixup.getLoc(), "relocation variant " +
70                                           A64E->getVariantKindName() +
71                                           " unsupported on COFF targets");
72       return COFF::IMAGE_REL_ARM64_ABSOLUTE; // Dummy return value
73     }
74   }
75 
76   switch (FixupKind) {
77   default: {
78     if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
79       Ctx.reportError(Fixup.getLoc(), "relocation type " +
80                                           A64E->getVariantKindName() +
81                                           " unsupported on COFF targets");
82     } else {
83       const MCFixupKindInfo &Info = MAB.getFixupKindInfo(Fixup.getKind());
84       Ctx.reportError(Fixup.getLoc(), Twine("relocation type ") + Info.Name +
85                                           " unsupported on COFF targets");
86     }
87     return COFF::IMAGE_REL_ARM64_ABSOLUTE; // Dummy return value
88   }
89 
90   case FK_PCRel_4:
91     return COFF::IMAGE_REL_ARM64_REL32;
92 
93   case FK_Data_4:
94     switch (Modifier) {
95     default:
96       return COFF::IMAGE_REL_ARM64_ADDR32;
97     case MCSymbolRefExpr::VK_COFF_IMGREL32:
98       return COFF::IMAGE_REL_ARM64_ADDR32NB;
99     case MCSymbolRefExpr::VK_SECREL:
100       return COFF::IMAGE_REL_ARM64_SECREL;
101     }
102 
103   case FK_Data_8:
104     return COFF::IMAGE_REL_ARM64_ADDR64;
105 
106   case FK_SecRel_2:
107     return COFF::IMAGE_REL_ARM64_SECTION;
108 
109   case FK_SecRel_4:
110     return COFF::IMAGE_REL_ARM64_SECREL;
111 
112   case AArch64::fixup_aarch64_add_imm12:
113     if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
114       AArch64MCExpr::VariantKind RefKind = A64E->getKind();
115       if (RefKind == AArch64MCExpr::VK_SECREL_LO12)
116         return COFF::IMAGE_REL_ARM64_SECREL_LOW12A;
117       if (RefKind == AArch64MCExpr::VK_SECREL_HI12)
118         return COFF::IMAGE_REL_ARM64_SECREL_HIGH12A;
119     }
120     return COFF::IMAGE_REL_ARM64_PAGEOFFSET_12A;
121 
122   case AArch64::fixup_aarch64_ldst_imm12_scale1:
123   case AArch64::fixup_aarch64_ldst_imm12_scale2:
124   case AArch64::fixup_aarch64_ldst_imm12_scale4:
125   case AArch64::fixup_aarch64_ldst_imm12_scale8:
126   case AArch64::fixup_aarch64_ldst_imm12_scale16:
127     if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
128       AArch64MCExpr::VariantKind RefKind = A64E->getKind();
129       if (RefKind == AArch64MCExpr::VK_SECREL_LO12)
130         return COFF::IMAGE_REL_ARM64_SECREL_LOW12L;
131     }
132     return COFF::IMAGE_REL_ARM64_PAGEOFFSET_12L;
133 
134   case AArch64::fixup_aarch64_pcrel_adr_imm21:
135     return COFF::IMAGE_REL_ARM64_REL21;
136 
137   case AArch64::fixup_aarch64_pcrel_adrp_imm21:
138     return COFF::IMAGE_REL_ARM64_PAGEBASE_REL21;
139 
140   case AArch64::fixup_aarch64_pcrel_branch14:
141     return COFF::IMAGE_REL_ARM64_BRANCH14;
142 
143   case AArch64::fixup_aarch64_pcrel_branch19:
144     return COFF::IMAGE_REL_ARM64_BRANCH19;
145 
146   case AArch64::fixup_aarch64_pcrel_branch26:
147   case AArch64::fixup_aarch64_pcrel_call26:
148     return COFF::IMAGE_REL_ARM64_BRANCH26;
149   }
150 }
151 
152 bool AArch64WinCOFFObjectWriter::recordRelocation(const MCFixup &Fixup) const {
153   return true;
154 }
155 
156 namespace llvm {
157 
158 std::unique_ptr<MCObjectTargetWriter> createAArch64WinCOFFObjectWriter() {
159   return std::make_unique<AArch64WinCOFFObjectWriter>();
160 }
161 
162 } // end namespace llvm
163