1 //===-- SystemZMCObjectWriter.cpp - SystemZ ELF writer --------------------===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9
10 #include "MCTargetDesc/SystemZMCTargetDesc.h"
11 #include "MCTargetDesc/SystemZMCFixups.h"
12 #include "llvm/MC/MCELFObjectWriter.h"
13 #include "llvm/MC/MCExpr.h"
14 #include "llvm/MC/MCValue.h"
15
16 using namespace llvm;
17
18 namespace {
19 class SystemZObjectWriter : public MCELFObjectTargetWriter {
20 public:
21 SystemZObjectWriter(uint8_t OSABI);
22
23 ~SystemZObjectWriter() override;
24
25 protected:
26 // Override MCELFObjectTargetWriter.
27 unsigned getRelocType(MCContext &Ctx, const MCValue &Target,
28 const MCFixup &Fixup, bool IsPCRel) const override;
29 };
30 } // end anonymous namespace
31
SystemZObjectWriter(uint8_t OSABI)32 SystemZObjectWriter::SystemZObjectWriter(uint8_t OSABI)
33 : MCELFObjectTargetWriter(/*Is64Bit=*/true, OSABI, ELF::EM_S390,
34 /*HasRelocationAddend=*/ true) {}
35
~SystemZObjectWriter()36 SystemZObjectWriter::~SystemZObjectWriter() {
37 }
38
39 // Return the relocation type for an absolute value of MCFixupKind Kind.
getAbsoluteReloc(unsigned Kind)40 static unsigned getAbsoluteReloc(unsigned Kind) {
41 switch (Kind) {
42 case FK_Data_1: return ELF::R_390_8;
43 case FK_Data_2: return ELF::R_390_16;
44 case FK_Data_4: return ELF::R_390_32;
45 case FK_Data_8: return ELF::R_390_64;
46 }
47 llvm_unreachable("Unsupported absolute address");
48 }
49
50 // Return the relocation type for a PC-relative value of MCFixupKind Kind.
getPCRelReloc(unsigned Kind)51 static unsigned getPCRelReloc(unsigned Kind) {
52 switch (Kind) {
53 case FK_Data_2: return ELF::R_390_PC16;
54 case FK_Data_4: return ELF::R_390_PC32;
55 case FK_Data_8: return ELF::R_390_PC64;
56 case SystemZ::FK_390_PC16DBL: return ELF::R_390_PC16DBL;
57 case SystemZ::FK_390_PC32DBL: return ELF::R_390_PC32DBL;
58 }
59 llvm_unreachable("Unsupported PC-relative address");
60 }
61
62 // Return the R_390_TLS_LE* relocation type for MCFixupKind Kind.
getTLSLEReloc(unsigned Kind)63 static unsigned getTLSLEReloc(unsigned Kind) {
64 switch (Kind) {
65 case FK_Data_4: return ELF::R_390_TLS_LE32;
66 case FK_Data_8: return ELF::R_390_TLS_LE64;
67 }
68 llvm_unreachable("Unsupported absolute address");
69 }
70
71 // Return the R_390_TLS_LDO* relocation type for MCFixupKind Kind.
getTLSLDOReloc(unsigned Kind)72 static unsigned getTLSLDOReloc(unsigned Kind) {
73 switch (Kind) {
74 case FK_Data_4: return ELF::R_390_TLS_LDO32;
75 case FK_Data_8: return ELF::R_390_TLS_LDO64;
76 }
77 llvm_unreachable("Unsupported absolute address");
78 }
79
80 // Return the R_390_TLS_LDM* relocation type for MCFixupKind Kind.
getTLSLDMReloc(unsigned Kind)81 static unsigned getTLSLDMReloc(unsigned Kind) {
82 switch (Kind) {
83 case FK_Data_4: return ELF::R_390_TLS_LDM32;
84 case FK_Data_8: return ELF::R_390_TLS_LDM64;
85 case SystemZ::FK_390_TLS_CALL: return ELF::R_390_TLS_LDCALL;
86 }
87 llvm_unreachable("Unsupported absolute address");
88 }
89
90 // Return the R_390_TLS_GD* relocation type for MCFixupKind Kind.
getTLSGDReloc(unsigned Kind)91 static unsigned getTLSGDReloc(unsigned Kind) {
92 switch (Kind) {
93 case FK_Data_4: return ELF::R_390_TLS_GD32;
94 case FK_Data_8: return ELF::R_390_TLS_GD64;
95 case SystemZ::FK_390_TLS_CALL: return ELF::R_390_TLS_GDCALL;
96 }
97 llvm_unreachable("Unsupported absolute address");
98 }
99
100 // Return the PLT relocation counterpart of MCFixupKind Kind.
getPLTReloc(unsigned Kind)101 static unsigned getPLTReloc(unsigned Kind) {
102 switch (Kind) {
103 case SystemZ::FK_390_PC16DBL: return ELF::R_390_PLT16DBL;
104 case SystemZ::FK_390_PC32DBL: return ELF::R_390_PLT32DBL;
105 }
106 llvm_unreachable("Unsupported absolute address");
107 }
108
getRelocType(MCContext & Ctx,const MCValue & Target,const MCFixup & Fixup,bool IsPCRel) const109 unsigned SystemZObjectWriter::getRelocType(MCContext &Ctx,
110 const MCValue &Target,
111 const MCFixup &Fixup,
112 bool IsPCRel) const {
113 MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
114 unsigned Kind = Fixup.getKind();
115 switch (Modifier) {
116 case MCSymbolRefExpr::VK_None:
117 if (IsPCRel)
118 return getPCRelReloc(Kind);
119 return getAbsoluteReloc(Kind);
120
121 case MCSymbolRefExpr::VK_NTPOFF:
122 assert(!IsPCRel && "NTPOFF shouldn't be PC-relative");
123 return getTLSLEReloc(Kind);
124
125 case MCSymbolRefExpr::VK_INDNTPOFF:
126 if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
127 return ELF::R_390_TLS_IEENT;
128 llvm_unreachable("Only PC-relative INDNTPOFF accesses are supported for now");
129
130 case MCSymbolRefExpr::VK_DTPOFF:
131 assert(!IsPCRel && "DTPOFF shouldn't be PC-relative");
132 return getTLSLDOReloc(Kind);
133
134 case MCSymbolRefExpr::VK_TLSLDM:
135 assert(!IsPCRel && "TLSLDM shouldn't be PC-relative");
136 return getTLSLDMReloc(Kind);
137
138 case MCSymbolRefExpr::VK_TLSGD:
139 assert(!IsPCRel && "TLSGD shouldn't be PC-relative");
140 return getTLSGDReloc(Kind);
141
142 case MCSymbolRefExpr::VK_GOT:
143 if (IsPCRel && Kind == SystemZ::FK_390_PC32DBL)
144 return ELF::R_390_GOTENT;
145 llvm_unreachable("Only PC-relative GOT accesses are supported for now");
146
147 case MCSymbolRefExpr::VK_PLT:
148 assert(IsPCRel && "@PLT shouldt be PC-relative");
149 return getPLTReloc(Kind);
150
151 default:
152 llvm_unreachable("Modifier not supported");
153 }
154 }
155
createSystemZObjectWriter(raw_pwrite_stream & OS,uint8_t OSABI)156 MCObjectWriter *llvm::createSystemZObjectWriter(raw_pwrite_stream &OS,
157 uint8_t OSABI) {
158 MCELFObjectTargetWriter *MOTW = new SystemZObjectWriter(OSABI);
159 return createELFObjectWriter(MOTW, OS, /*IsLittleEndian=*/false);
160 }
161