1 //===-- SystemZMCObjectWriter.cpp - SystemZ ELF writer --------------------===//
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/SystemZMCFixups.h"
10 #include "MCTargetDesc/SystemZMCTargetDesc.h"
11 #include "llvm/BinaryFormat/ELF.h"
12 #include "llvm/MC/MCELFObjectWriter.h"
13 #include "llvm/MC/MCExpr.h"
14 #include "llvm/MC/MCFixup.h"
15 #include "llvm/MC/MCObjectWriter.h"
16 #include "llvm/MC/MCValue.h"
17 #include "llvm/Support/ErrorHandling.h"
18 #include <cassert>
19 #include <cstdint>
20
21 using namespace llvm;
22
23 namespace {
24
25 class SystemZObjectWriter : public MCELFObjectTargetWriter {
26 public:
27 SystemZObjectWriter(uint8_t OSABI);
28 ~SystemZObjectWriter() override = default;
29
30 protected:
31 // Override MCELFObjectTargetWriter.
32 unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
33 const MCFixup &Fixup, bool IsPCRel) const override;
34 };
35
36 } // end anonymous namespace
37
SystemZObjectWriter(uint8_t OSABI)38 SystemZObjectWriter::SystemZObjectWriter(uint8_t OSABI)
39 : MCELFObjectTargetWriter(/*Is64Bit_=*/true, OSABI, ELF::EM_S390,
40 /*HasRelocationAddend_=*/ true) {}
41
42 // Return the relocation type for an absolute value of MCFixupKind Kind.
getAbsoluteReloc(unsigned Kind)43 static unsigned getAbsoluteReloc(unsigned Kind) {
44 switch (Kind) {
45 case FK_Data_1: return ELF::R_390_8;
46 case FK_Data_2: return ELF::R_390_16;
47 case FK_Data_4: return ELF::R_390_32;
48 case FK_Data_8: return ELF::R_390_64;
49 }
50 llvm_unreachable("Unsupported absolute address");
51 }
52
53 // Return the relocation type for a PC-relative value of MCFixupKind Kind.
getPCRelReloc(unsigned Kind)54 static unsigned getPCRelReloc(unsigned Kind) {
55 switch (Kind) {
56 case FK_Data_2: return ELF::R_390_PC16;
57 case FK_Data_4: return ELF::R_390_PC32;
58 case FK_Data_8: return ELF::R_390_PC64;
59 case SystemZ::FK_390_PC12DBL: return ELF::R_390_PC12DBL;
60 case SystemZ::FK_390_PC16DBL: return ELF::R_390_PC16DBL;
61 case SystemZ::FK_390_PC24DBL: return ELF::R_390_PC24DBL;
62 case SystemZ::FK_390_PC32DBL: return ELF::R_390_PC32DBL;
63 }
64 llvm_unreachable("Unsupported PC-relative address");
65 }
66
67 // Return the R_390_TLS_LE* relocation type for MCFixupKind Kind.
getTLSLEReloc(unsigned Kind)68 static unsigned getTLSLEReloc(unsigned Kind) {
69 switch (Kind) {
70 case FK_Data_4: return ELF::R_390_TLS_LE32;
71 case FK_Data_8: return ELF::R_390_TLS_LE64;
72 }
73 llvm_unreachable("Unsupported absolute address");
74 }
75
76 // Return the R_390_TLS_LDO* relocation type for MCFixupKind Kind.
getTLSLDOReloc(unsigned Kind)77 static unsigned getTLSLDOReloc(unsigned Kind) {
78 switch (Kind) {
79 case FK_Data_4: return ELF::R_390_TLS_LDO32;
80 case FK_Data_8: return ELF::R_390_TLS_LDO64;
81 }
82 llvm_unreachable("Unsupported absolute address");
83 }
84
85 // Return the R_390_TLS_LDM* relocation type for MCFixupKind Kind.
getTLSLDMReloc(unsigned Kind)86 static unsigned getTLSLDMReloc(unsigned Kind) {
87 switch (Kind) {
88 case FK_Data_4: return ELF::R_390_TLS_LDM32;
89 case FK_Data_8: return ELF::R_390_TLS_LDM64;
90 case SystemZ::FK_390_TLS_CALL: return ELF::R_390_TLS_LDCALL;
91 }
92 llvm_unreachable("Unsupported absolute address");
93 }
94
95 // Return the R_390_TLS_GD* relocation type for MCFixupKind Kind.
getTLSGDReloc(unsigned Kind)96 static unsigned getTLSGDReloc(unsigned Kind) {
97 switch (Kind) {
98 case FK_Data_4: return ELF::R_390_TLS_GD32;
99 case FK_Data_8: return ELF::R_390_TLS_GD64;
100 case SystemZ::FK_390_TLS_CALL: return ELF::R_390_TLS_GDCALL;
101 }
102 llvm_unreachable("Unsupported absolute address");
103 }
104
105 // Return the PLT relocation counterpart of MCFixupKind Kind.
getPLTReloc(unsigned Kind)106 static unsigned getPLTReloc(unsigned Kind) {
107 switch (Kind) {
108 case SystemZ::FK_390_PC12DBL: return ELF::R_390_PLT12DBL;
109 case SystemZ::FK_390_PC16DBL: return ELF::R_390_PLT16DBL;
110 case SystemZ::FK_390_PC24DBL: return ELF::R_390_PLT24DBL;
111 case SystemZ::FK_390_PC32DBL: return ELF::R_390_PLT32DBL;
112 }
113 llvm_unreachable("Unsupported absolute address");
114 }
115
getRelocType(MCContext & Ctx,const MCValue & Target,const MCFixup & Fixup,bool IsPCRel) const116 unsigned SystemZObjectWriter::getRelocType(MCContext &Ctx,
117 const MCValue &Target,
118 const MCFixup &Fixup,
119 bool IsPCRel) const {
120 MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
121 unsigned Kind = Fixup.getKind();
122 switch (Modifier) {
123 case MCSymbolRefExpr::VK_None:
124 if (IsPCRel)
125 return getPCRelReloc(Kind);
126 return getAbsoluteReloc(Kind);
127
128 case MCSymbolRefExpr::VK_NTPOFF:
129 assert(!IsPCRel && "NTPOFF shouldn't be PC-relative");
130 return getTLSLEReloc(Kind);
131
132 case MCSymbolRefExpr::VK_INDNTPOFF:
133 if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
134 return ELF::R_390_TLS_IEENT;
135 llvm_unreachable("Only PC-relative INDNTPOFF accesses are supported for now");
136
137 case MCSymbolRefExpr::VK_DTPOFF:
138 assert(!IsPCRel && "DTPOFF shouldn't be PC-relative");
139 return getTLSLDOReloc(Kind);
140
141 case MCSymbolRefExpr::VK_TLSLDM:
142 assert(!IsPCRel && "TLSLDM shouldn't be PC-relative");
143 return getTLSLDMReloc(Kind);
144
145 case MCSymbolRefExpr::VK_TLSGD:
146 assert(!IsPCRel && "TLSGD shouldn't be PC-relative");
147 return getTLSGDReloc(Kind);
148
149 case MCSymbolRefExpr::VK_GOT:
150 if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
151 return ELF::R_390_GOTENT;
152 llvm_unreachable("Only PC-relative GOT accesses are supported for now");
153
154 case MCSymbolRefExpr::VK_PLT:
155 assert(IsPCRel && "@PLT shouldt be PC-relative");
156 return getPLTReloc(Kind);
157
158 default:
159 llvm_unreachable("Modifier not supported");
160 }
161 }
162
163 std::unique_ptr<MCObjectTargetWriter>
createSystemZObjectWriter(uint8_t OSABI)164 llvm::createSystemZObjectWriter(uint8_t OSABI) {
165 return std::make_unique<SystemZObjectWriter>(OSABI);
166 }
167