1 //===---------- M68kELFObjectWriter.cpp - M68k ELF 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 /// \file
10 /// This file contains definitions for M68k ELF Writers
11 ///
12 //===----------------------------------------------------------------------===//
13 
14 #include "MCTargetDesc/M68kFixupKinds.h"
15 #include "MCTargetDesc/M68kMCTargetDesc.h"
16 
17 #include "llvm/BinaryFormat/ELF.h"
18 #include "llvm/MC/MCAsmInfo.h"
19 #include "llvm/MC/MCContext.h"
20 #include "llvm/MC/MCELFObjectWriter.h"
21 #include "llvm/MC/MCExpr.h"
22 #include "llvm/MC/MCValue.h"
23 #include "llvm/Support/ErrorHandling.h"
24 
25 using namespace llvm;
26 
27 namespace {
28 class M68kELFObjectWriter : public MCELFObjectTargetWriter {
29 public:
30   M68kELFObjectWriter(uint8_t OSABI);
31 
32   ~M68kELFObjectWriter() override;
33 
34 protected:
35   unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
36                         const MCFixup &Fixup, bool IsPCRel) const override;
37 };
38 } // namespace
39 
40 M68kELFObjectWriter::M68kELFObjectWriter(uint8_t OSABI)
41     : MCELFObjectTargetWriter(false, OSABI, ELF::EM_68K, /* RELA */ true) {}
42 
43 M68kELFObjectWriter::~M68kELFObjectWriter() {}
44 
45 enum M68kRelType { RT_32, RT_16, RT_8 };
46 
47 static M68kRelType
48 getType(unsigned Kind, MCSymbolRefExpr::VariantKind &Modifier, bool &IsPCRel) {
49   switch (Kind) {
50   case FK_Data_4:
51   case FK_PCRel_4:
52     return RT_32;
53   case FK_PCRel_2:
54   case FK_Data_2:
55     return RT_16;
56   case FK_PCRel_1:
57   case FK_Data_1:
58     return RT_8;
59   }
60   llvm_unreachable("Unimplemented");
61 }
62 
63 unsigned M68kELFObjectWriter::getRelocType(MCContext &Ctx,
64                                            const MCValue &Target,
65                                            const MCFixup &Fixup,
66                                            bool IsPCRel) const {
67   MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
68   unsigned Kind = Fixup.getKind();
69   M68kRelType Type = getType(Kind, Modifier, IsPCRel);
70   switch (Modifier) {
71   default:
72     llvm_unreachable("Unimplemented");
73   case MCSymbolRefExpr::VK_None:
74     switch (Type) {
75     case RT_32:
76       return IsPCRel ? ELF::R_68K_PC32 : ELF::R_68K_32;
77     case RT_16:
78       return IsPCRel ? ELF::R_68K_PC16 : ELF::R_68K_16;
79     case RT_8:
80       return IsPCRel ? ELF::R_68K_PC8 : ELF::R_68K_8;
81     }
82     llvm_unreachable("Unrecognized size");
83   case MCSymbolRefExpr::VK_GOTPCREL:
84     switch (Type) {
85     case RT_32:
86       return ELF::R_68K_GOTPCREL32;
87     case RT_16:
88       return ELF::R_68K_GOTPCREL16;
89     case RT_8:
90       return ELF::R_68K_GOTPCREL8;
91     }
92     llvm_unreachable("Unrecognized size");
93   case MCSymbolRefExpr::VK_GOTOFF:
94     assert(!IsPCRel);
95     switch (Type) {
96     case RT_32:
97       return ELF::R_68K_GOTOFF32;
98     case RT_16:
99       return ELF::R_68K_GOTOFF16;
100     case RT_8:
101       return ELF::R_68K_GOTOFF8;
102     }
103     llvm_unreachable("Unrecognized size");
104   case MCSymbolRefExpr::VK_PLT:
105     switch (Type) {
106     case RT_32:
107       return ELF::R_68K_PLT32;
108     case RT_16:
109       return ELF::R_68K_PLT16;
110     case RT_8:
111       return ELF::R_68K_PLT8;
112     }
113     llvm_unreachable("Unrecognized size");
114   }
115 }
116 
117 std::unique_ptr<MCObjectTargetWriter>
118 llvm::createM68kELFObjectWriter(uint8_t OSABI) {
119   return std::make_unique<M68kELFObjectWriter>(OSABI);
120 }
121