1 //===-- X86ELFObjectWriter.cpp - X86 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/X86FixupKinds.h"
11 #include "MCTargetDesc/X86MCTargetDesc.h"
12 #include "llvm/MC/MCELFObjectWriter.h"
13 #include "llvm/MC/MCExpr.h"
14 #include "llvm/MC/MCValue.h"
15 #include "llvm/Support/ELF.h"
16 #include "llvm/Support/ErrorHandling.h"
17
18 using namespace llvm;
19
20 namespace {
21 class X86ELFObjectWriter : public MCELFObjectTargetWriter {
22 public:
23 X86ELFObjectWriter(bool IsELF64, uint8_t OSABI, uint16_t EMachine);
24
25 virtual ~X86ELFObjectWriter();
26 protected:
27 unsigned GetRelocType(const MCValue &Target, const MCFixup &Fixup,
28 bool IsPCRel) const override;
29 };
30 }
31
X86ELFObjectWriter(bool IsELF64,uint8_t OSABI,uint16_t EMachine)32 X86ELFObjectWriter::X86ELFObjectWriter(bool IsELF64, uint8_t OSABI,
33 uint16_t EMachine)
34 : MCELFObjectTargetWriter(IsELF64, OSABI, EMachine,
35 // Only i386 uses Rel instead of RelA.
36 /*HasRelocationAddend*/ EMachine != ELF::EM_386) {}
37
~X86ELFObjectWriter()38 X86ELFObjectWriter::~X86ELFObjectWriter()
39 {}
40
GetRelocType(const MCValue & Target,const MCFixup & Fixup,bool IsPCRel) const41 unsigned X86ELFObjectWriter::GetRelocType(const MCValue &Target,
42 const MCFixup &Fixup,
43 bool IsPCRel) const {
44 // determine the type of the relocation
45
46 MCSymbolRefExpr::VariantKind Modifier = Target.getAccessVariant();
47 unsigned Type;
48 if (getEMachine() == ELF::EM_X86_64) {
49 if (IsPCRel) {
50 switch ((unsigned)Fixup.getKind()) {
51 default: llvm_unreachable("invalid fixup kind!");
52
53 case FK_Data_8: Type = ELF::R_X86_64_PC64; break;
54 case FK_Data_4: Type = ELF::R_X86_64_PC32; break;
55 case FK_Data_2: Type = ELF::R_X86_64_PC16; break;
56 case FK_Data_1: Type = ELF::R_X86_64_PC8; break;
57
58 case FK_PCRel_8:
59 assert(Modifier == MCSymbolRefExpr::VK_None);
60 Type = ELF::R_X86_64_PC64;
61 break;
62 case X86::reloc_signed_4byte:
63 case X86::reloc_riprel_4byte_movq_load:
64 case X86::reloc_riprel_4byte:
65 case FK_PCRel_4:
66 switch (Modifier) {
67 default:
68 llvm_unreachable("Unimplemented");
69 case MCSymbolRefExpr::VK_None:
70 Type = ELF::R_X86_64_PC32;
71 break;
72 case MCSymbolRefExpr::VK_PLT:
73 Type = ELF::R_X86_64_PLT32;
74 break;
75 case MCSymbolRefExpr::VK_GOTPCREL:
76 Type = ELF::R_X86_64_GOTPCREL;
77 break;
78 case MCSymbolRefExpr::VK_GOTTPOFF:
79 Type = ELF::R_X86_64_GOTTPOFF;
80 break;
81 case MCSymbolRefExpr::VK_TLSGD:
82 Type = ELF::R_X86_64_TLSGD;
83 break;
84 case MCSymbolRefExpr::VK_TLSLD:
85 Type = ELF::R_X86_64_TLSLD;
86 break;
87 }
88 break;
89 case FK_PCRel_2:
90 assert(Modifier == MCSymbolRefExpr::VK_None);
91 Type = ELF::R_X86_64_PC16;
92 break;
93 case FK_PCRel_1:
94 assert(Modifier == MCSymbolRefExpr::VK_None);
95 Type = ELF::R_X86_64_PC8;
96 break;
97 }
98 } else {
99 switch ((unsigned)Fixup.getKind()) {
100 default: llvm_unreachable("invalid fixup kind!");
101 case X86::reloc_global_offset_table8:
102 Type = ELF::R_X86_64_GOTPC64;
103 break;
104 case X86::reloc_global_offset_table:
105 Type = ELF::R_X86_64_GOTPC32;
106 break;
107 case FK_Data_8:
108 switch (Modifier) {
109 default:
110 llvm_unreachable("Unimplemented");
111 case MCSymbolRefExpr::VK_None:
112 Type = ELF::R_X86_64_64;
113 break;
114 case MCSymbolRefExpr::VK_GOT:
115 Type = ELF::R_X86_64_GOT64;
116 break;
117 case MCSymbolRefExpr::VK_GOTOFF:
118 Type = ELF::R_X86_64_GOTOFF64;
119 break;
120 case MCSymbolRefExpr::VK_TPOFF:
121 Type = ELF::R_X86_64_TPOFF64;
122 break;
123 case MCSymbolRefExpr::VK_DTPOFF:
124 Type = ELF::R_X86_64_DTPOFF64;
125 break;
126 }
127 break;
128 case X86::reloc_signed_4byte:
129 switch (Modifier) {
130 default:
131 llvm_unreachable("Unimplemented");
132 case MCSymbolRefExpr::VK_None:
133 Type = ELF::R_X86_64_32S;
134 break;
135 case MCSymbolRefExpr::VK_GOT:
136 Type = ELF::R_X86_64_GOT32;
137 break;
138 case MCSymbolRefExpr::VK_GOTPCREL:
139 Type = ELF::R_X86_64_GOTPCREL;
140 break;
141 case MCSymbolRefExpr::VK_TPOFF:
142 Type = ELF::R_X86_64_TPOFF32;
143 break;
144 case MCSymbolRefExpr::VK_DTPOFF:
145 Type = ELF::R_X86_64_DTPOFF32;
146 break;
147 }
148 break;
149 case FK_Data_4:
150 Type = ELF::R_X86_64_32;
151 break;
152 case FK_Data_2: Type = ELF::R_X86_64_16; break;
153 case FK_PCRel_1:
154 case FK_Data_1: Type = ELF::R_X86_64_8; break;
155 }
156 }
157 } else if (getEMachine() == ELF::EM_386) {
158 if (IsPCRel) {
159 switch ((unsigned)Fixup.getKind()) {
160 default: llvm_unreachable("invalid fixup kind!");
161
162 case X86::reloc_global_offset_table:
163 Type = ELF::R_386_GOTPC;
164 break;
165
166 case FK_PCRel_1:
167 case FK_Data_1:
168 switch (Modifier) {
169 default:
170 llvm_unreachable("Unimplemented");
171 case MCSymbolRefExpr::VK_None:
172 Type = ELF::R_386_PC8;
173 break;
174 }
175 break;
176
177 case FK_PCRel_2:
178 case FK_Data_2:
179 switch (Modifier) {
180 default:
181 llvm_unreachable("Unimplemented");
182 case MCSymbolRefExpr::VK_None:
183 Type = ELF::R_386_PC16;
184 break;
185 }
186 break;
187
188 case X86::reloc_signed_4byte:
189 case FK_PCRel_4:
190 case FK_Data_4:
191 switch (Modifier) {
192 default:
193 llvm_unreachable("Unimplemented");
194 case MCSymbolRefExpr::VK_None:
195 Type = ELF::R_386_PC32;
196 break;
197 case MCSymbolRefExpr::VK_PLT:
198 Type = ELF::R_386_PLT32;
199 break;
200 }
201 break;
202 }
203 } else {
204 switch ((unsigned)Fixup.getKind()) {
205 default: llvm_unreachable("invalid fixup kind!");
206
207 case X86::reloc_global_offset_table:
208 Type = ELF::R_386_GOTPC;
209 break;
210
211 // FIXME: Should we avoid selecting reloc_signed_4byte in 32 bit mode
212 // instead?
213 case X86::reloc_signed_4byte:
214 case FK_PCRel_4:
215 case FK_Data_4:
216 switch (Modifier) {
217 default:
218 llvm_unreachable("Unimplemented");
219 case MCSymbolRefExpr::VK_None:
220 Type = ELF::R_386_32;
221 break;
222 case MCSymbolRefExpr::VK_GOT:
223 Type = ELF::R_386_GOT32;
224 break;
225 case MCSymbolRefExpr::VK_PLT:
226 Type = ELF::R_386_PLT32;
227 break;
228 case MCSymbolRefExpr::VK_GOTOFF:
229 Type = ELF::R_386_GOTOFF;
230 break;
231 case MCSymbolRefExpr::VK_TLSGD:
232 Type = ELF::R_386_TLS_GD;
233 break;
234 case MCSymbolRefExpr::VK_TPOFF:
235 Type = ELF::R_386_TLS_LE_32;
236 break;
237 case MCSymbolRefExpr::VK_INDNTPOFF:
238 Type = ELF::R_386_TLS_IE;
239 break;
240 case MCSymbolRefExpr::VK_NTPOFF:
241 Type = ELF::R_386_TLS_LE;
242 break;
243 case MCSymbolRefExpr::VK_GOTNTPOFF:
244 Type = ELF::R_386_TLS_GOTIE;
245 break;
246 case MCSymbolRefExpr::VK_TLSLDM:
247 Type = ELF::R_386_TLS_LDM;
248 break;
249 case MCSymbolRefExpr::VK_DTPOFF:
250 Type = ELF::R_386_TLS_LDO_32;
251 break;
252 case MCSymbolRefExpr::VK_GOTTPOFF:
253 Type = ELF::R_386_TLS_IE_32;
254 break;
255 }
256 break;
257 case FK_Data_2: Type = ELF::R_386_16; break;
258 case FK_PCRel_1:
259 case FK_Data_1: Type = ELF::R_386_8; break;
260 }
261 }
262 } else
263 llvm_unreachable("Unsupported ELF machine type.");
264
265 return Type;
266 }
267
createX86ELFObjectWriter(raw_ostream & OS,bool IsELF64,uint8_t OSABI,uint16_t EMachine)268 MCObjectWriter *llvm::createX86ELFObjectWriter(raw_ostream &OS,
269 bool IsELF64,
270 uint8_t OSABI,
271 uint16_t EMachine) {
272 MCELFObjectTargetWriter *MOTW =
273 new X86ELFObjectWriter(IsELF64, OSABI, EMachine);
274 return createELFObjectWriter(MOTW, OS, /*IsLittleEndian=*/true);
275 }
276