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 "AArch64MCTargetDesc.h"
10 #include "MCTargetDesc/AArch64FixupKinds.h"
11 #include "MCTargetDesc/AArch64MCExpr.h"
12 #include "llvm/ADT/Twine.h"
13 #include "llvm/BinaryFormat/COFF.h"
14 #include "llvm/MC/MCAsmBackend.h"
15 #include "llvm/MC/MCContext.h"
16 #include "llvm/MC/MCExpr.h"
17 #include "llvm/MC/MCFixup.h"
18 #include "llvm/MC/MCFixupKindInfo.h"
19 #include "llvm/MC/MCObjectWriter.h"
20 #include "llvm/MC/MCValue.h"
21 #include "llvm/MC/MCWinCOFFObjectWriter.h"
22 #include "llvm/Support/ErrorHandling.h"
23 #include "llvm/Support/raw_ostream.h"
24 #include <cassert>
25 
26 using namespace llvm;
27 
28 namespace {
29 
30 class AArch64WinCOFFObjectWriter : public MCWinCOFFObjectTargetWriter {
31 public:
32   AArch64WinCOFFObjectWriter()
33       : MCWinCOFFObjectTargetWriter(COFF::IMAGE_FILE_MACHINE_ARM64) {}
34 
35   ~AArch64WinCOFFObjectWriter() override = default;
36 
37   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
38                         const MCFixup &Fixup, bool IsCrossSection,
39                         const MCAsmBackend &MAB) const override;
40 
41   bool recordRelocation(const MCFixup &) const override;
42 };
43 
44 } // end anonymous namespace
45 
46 unsigned AArch64WinCOFFObjectWriter::getRelocType(
47     MCContext &Ctx, const MCValue &Target, const MCFixup &Fixup,
48     bool IsCrossSection, const MCAsmBackend &MAB) const {
49   unsigned FixupKind = Fixup.getKind();
50   if (IsCrossSection) {
51     if (FixupKind != FK_Data_4) {
52       Ctx.reportError(Fixup.getLoc(), "Cannot represent this expression");
53       return COFF::IMAGE_REL_ARM64_ADDR32;
54     }
55     FixupKind = FK_PCRel_4;
56   }
57 
58   auto Modifier = Target.isAbsolute() ? MCSymbolRefExpr::VK_None
59                                       : Target.getSymA()->getKind();
60   const MCExpr *Expr = Fixup.getValue();
61 
62   if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
63     AArch64MCExpr::VariantKind RefKind = A64E->getKind();
64     switch (AArch64MCExpr::getSymbolLoc(RefKind)) {
65     case AArch64MCExpr::VK_ABS:
66     case AArch64MCExpr::VK_SECREL:
67       // Supported
68       break;
69     default:
70       Ctx.reportError(Fixup.getLoc(), "relocation variant " +
71                                           A64E->getVariantKindName() +
72                                           " unsupported on COFF targets");
73       return COFF::IMAGE_REL_ARM64_ABSOLUTE; // Dummy return value
74     }
75   }
76 
77   switch (FixupKind) {
78   default: {
79     if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
80       Ctx.reportError(Fixup.getLoc(), "relocation type " +
81                                           A64E->getVariantKindName() +
82                                           " unsupported on COFF targets");
83     } else {
84       const MCFixupKindInfo &Info = MAB.getFixupKindInfo(Fixup.getKind());
85       Ctx.reportError(Fixup.getLoc(), Twine("relocation type ") + Info.Name +
86                                           " unsupported on COFF targets");
87     }
88     return COFF::IMAGE_REL_ARM64_ABSOLUTE; // Dummy return value
89   }
90 
91   case FK_PCRel_4:
92     return COFF::IMAGE_REL_ARM64_REL32;
93 
94   case FK_Data_4:
95     switch (Modifier) {
96     default:
97       return COFF::IMAGE_REL_ARM64_ADDR32;
98     case MCSymbolRefExpr::VK_COFF_IMGREL32:
99       return COFF::IMAGE_REL_ARM64_ADDR32NB;
100     case MCSymbolRefExpr::VK_SECREL:
101       return COFF::IMAGE_REL_ARM64_SECREL;
102     }
103 
104   case FK_Data_8:
105     return COFF::IMAGE_REL_ARM64_ADDR64;
106 
107   case FK_SecRel_2:
108     return COFF::IMAGE_REL_ARM64_SECTION;
109 
110   case FK_SecRel_4:
111     return COFF::IMAGE_REL_ARM64_SECREL;
112 
113   case AArch64::fixup_aarch64_add_imm12:
114     if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
115       AArch64MCExpr::VariantKind RefKind = A64E->getKind();
116       if (RefKind == AArch64MCExpr::VK_SECREL_LO12)
117         return COFF::IMAGE_REL_ARM64_SECREL_LOW12A;
118       if (RefKind == AArch64MCExpr::VK_SECREL_HI12)
119         return COFF::IMAGE_REL_ARM64_SECREL_HIGH12A;
120     }
121     return COFF::IMAGE_REL_ARM64_PAGEOFFSET_12A;
122 
123   case AArch64::fixup_aarch64_ldst_imm12_scale1:
124   case AArch64::fixup_aarch64_ldst_imm12_scale2:
125   case AArch64::fixup_aarch64_ldst_imm12_scale4:
126   case AArch64::fixup_aarch64_ldst_imm12_scale8:
127   case AArch64::fixup_aarch64_ldst_imm12_scale16:
128     if (const AArch64MCExpr *A64E = dyn_cast<AArch64MCExpr>(Expr)) {
129       AArch64MCExpr::VariantKind RefKind = A64E->getKind();
130       if (RefKind == AArch64MCExpr::VK_SECREL_LO12)
131         return COFF::IMAGE_REL_ARM64_SECREL_LOW12L;
132     }
133     return COFF::IMAGE_REL_ARM64_PAGEOFFSET_12L;
134 
135   case AArch64::fixup_aarch64_pcrel_adr_imm21:
136     return COFF::IMAGE_REL_ARM64_REL21;
137 
138   case AArch64::fixup_aarch64_pcrel_adrp_imm21:
139     return COFF::IMAGE_REL_ARM64_PAGEBASE_REL21;
140 
141   case AArch64::fixup_aarch64_pcrel_branch14:
142     return COFF::IMAGE_REL_ARM64_BRANCH14;
143 
144   case AArch64::fixup_aarch64_pcrel_branch19:
145     return COFF::IMAGE_REL_ARM64_BRANCH19;
146 
147   case AArch64::fixup_aarch64_pcrel_branch26:
148   case AArch64::fixup_aarch64_pcrel_call26:
149     return COFF::IMAGE_REL_ARM64_BRANCH26;
150   }
151 }
152 
153 bool AArch64WinCOFFObjectWriter::recordRelocation(const MCFixup &Fixup) const {
154   return true;
155 }
156 
157 std::unique_ptr<MCObjectTargetWriter> llvm::createAArch64WinCOFFObjectWriter() {
158   return std::make_unique<AArch64WinCOFFObjectWriter>();
159 }
160