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 case SystemZ::FK_390_12: return ELF::R_390_12;
50 case SystemZ::FK_390_20: return ELF::R_390_20;
51 }
52 llvm_unreachable("Unsupported absolute address");
53 }
54
55 // Return the relocation type for a PC-relative value of MCFixupKind Kind.
getPCRelReloc(unsigned Kind)56 static unsigned getPCRelReloc(unsigned Kind) {
57 switch (Kind) {
58 case FK_Data_2: return ELF::R_390_PC16;
59 case FK_Data_4: return ELF::R_390_PC32;
60 case FK_Data_8: return ELF::R_390_PC64;
61 case SystemZ::FK_390_PC12DBL: return ELF::R_390_PC12DBL;
62 case SystemZ::FK_390_PC16DBL: return ELF::R_390_PC16DBL;
63 case SystemZ::FK_390_PC24DBL: return ELF::R_390_PC24DBL;
64 case SystemZ::FK_390_PC32DBL: return ELF::R_390_PC32DBL;
65 }
66 llvm_unreachable("Unsupported PC-relative address");
67 }
68
69 // Return the R_390_TLS_LE* relocation type for MCFixupKind Kind.
getTLSLEReloc(unsigned Kind)70 static unsigned getTLSLEReloc(unsigned Kind) {
71 switch (Kind) {
72 case FK_Data_4: return ELF::R_390_TLS_LE32;
73 case FK_Data_8: return ELF::R_390_TLS_LE64;
74 }
75 llvm_unreachable("Unsupported absolute address");
76 }
77
78 // Return the R_390_TLS_LDO* relocation type for MCFixupKind Kind.
getTLSLDOReloc(unsigned Kind)79 static unsigned getTLSLDOReloc(unsigned Kind) {
80 switch (Kind) {
81 case FK_Data_4: return ELF::R_390_TLS_LDO32;
82 case FK_Data_8: return ELF::R_390_TLS_LDO64;
83 }
84 llvm_unreachable("Unsupported absolute address");
85 }
86
87 // Return the R_390_TLS_LDM* relocation type for MCFixupKind Kind.
getTLSLDMReloc(unsigned Kind)88 static unsigned getTLSLDMReloc(unsigned Kind) {
89 switch (Kind) {
90 case FK_Data_4: return ELF::R_390_TLS_LDM32;
91 case FK_Data_8: return ELF::R_390_TLS_LDM64;
92 case SystemZ::FK_390_TLS_CALL: return ELF::R_390_TLS_LDCALL;
93 }
94 llvm_unreachable("Unsupported absolute address");
95 }
96
97 // Return the R_390_TLS_GD* relocation type for MCFixupKind Kind.
getTLSGDReloc(unsigned Kind)98 static unsigned getTLSGDReloc(unsigned Kind) {
99 switch (Kind) {
100 case FK_Data_4: return ELF::R_390_TLS_GD32;
101 case FK_Data_8: return ELF::R_390_TLS_GD64;
102 case SystemZ::FK_390_TLS_CALL: return ELF::R_390_TLS_GDCALL;
103 }
104 llvm_unreachable("Unsupported absolute address");
105 }
106
107 // Return the PLT relocation counterpart of MCFixupKind Kind.
getPLTReloc(unsigned Kind)108 static unsigned getPLTReloc(unsigned Kind) {
109 switch (Kind) {
110 case SystemZ::FK_390_PC12DBL: return ELF::R_390_PLT12DBL;
111 case SystemZ::FK_390_PC16DBL: return ELF::R_390_PLT16DBL;
112 case SystemZ::FK_390_PC24DBL: return ELF::R_390_PLT24DBL;
113 case SystemZ::FK_390_PC32DBL: return ELF::R_390_PLT32DBL;
114 }
115 llvm_unreachable("Unsupported absolute address");
116 }
117
getRelocType(MCContext & Ctx,const MCValue & Target,const MCFixup & Fixup,bool IsPCRel) const118 unsigned SystemZObjectWriter::getRelocType(MCContext &Ctx,
119 const MCValue &Target,
120 const MCFixup &Fixup,
121 bool IsPCRel) const {
122 unsigned Kind = Fixup.getKind();
123 if (Kind >= FirstLiteralRelocationKind)
124 return Kind - FirstLiteralRelocationKind;
125 MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
126 switch (Modifier) {
127 case MCSymbolRefExpr::VK_None:
128 if (IsPCRel)
129 return getPCRelReloc(Kind);
130 return getAbsoluteReloc(Kind);
131
132 case MCSymbolRefExpr::VK_NTPOFF:
133 assert(!IsPCRel && "NTPOFF shouldn't be PC-relative");
134 return getTLSLEReloc(Kind);
135
136 case MCSymbolRefExpr::VK_INDNTPOFF:
137 if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
138 return ELF::R_390_TLS_IEENT;
139 llvm_unreachable("Only PC-relative INDNTPOFF accesses are supported for now");
140
141 case MCSymbolRefExpr::VK_DTPOFF:
142 assert(!IsPCRel && "DTPOFF shouldn't be PC-relative");
143 return getTLSLDOReloc(Kind);
144
145 case MCSymbolRefExpr::VK_TLSLDM:
146 assert(!IsPCRel && "TLSLDM shouldn't be PC-relative");
147 return getTLSLDMReloc(Kind);
148
149 case MCSymbolRefExpr::VK_TLSGD:
150 assert(!IsPCRel && "TLSGD shouldn't be PC-relative");
151 return getTLSGDReloc(Kind);
152
153 case MCSymbolRefExpr::VK_GOT:
154 if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
155 return ELF::R_390_GOTENT;
156 llvm_unreachable("Only PC-relative GOT accesses are supported for now");
157
158 case MCSymbolRefExpr::VK_PLT:
159 assert(IsPCRel && "@PLT shouldt be PC-relative");
160 return getPLTReloc(Kind);
161
162 default:
163 llvm_unreachable("Modifier not supported");
164 }
165 }
166
167 std::unique_ptr<MCObjectTargetWriter>
createSystemZObjectWriter(uint8_t OSABI)168 llvm::createSystemZObjectWriter(uint8_t OSABI) {
169 return std::make_unique<SystemZObjectWriter>(OSABI);
170 }
171