1 //===-- PPCELFObjectWriter.cpp - PPC 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/PPCFixupKinds.h" 10 #include "MCTargetDesc/PPCMCExpr.h" 11 #include "MCTargetDesc/PPCMCTargetDesc.h" 12 #include "llvm/ADT/STLExtras.h" 13 #include "llvm/MC/MCELFObjectWriter.h" 14 #include "llvm/MC/MCExpr.h" 15 #include "llvm/MC/MCObjectWriter.h" 16 #include "llvm/MC/MCSymbolELF.h" 17 #include "llvm/MC/MCValue.h" 18 #include "llvm/Support/ErrorHandling.h" 19 20 using namespace llvm; 21 22 namespace { 23 class PPCELFObjectWriter : public MCELFObjectTargetWriter { 24 public: 25 PPCELFObjectWriter(bool Is64Bit, uint8_t OSABI); 26 27 protected: 28 unsigned getRelocType(MCContext &Ctx, const MCValue &Target, 29 const MCFixup &Fixup, bool IsPCRel) const override; 30 31 bool needsRelocateWithSymbol(const MCSymbol &Sym, 32 unsigned Type) const override; 33 }; 34 } 35 36 PPCELFObjectWriter::PPCELFObjectWriter(bool Is64Bit, uint8_t OSABI) 37 : MCELFObjectTargetWriter(Is64Bit, OSABI, 38 Is64Bit ? ELF::EM_PPC64 : ELF::EM_PPC, 39 /*HasRelocationAddend*/ true) {} 40 41 static MCSymbolRefExpr::VariantKind getAccessVariant(const MCValue &Target, 42 const MCFixup &Fixup) { 43 const MCExpr *Expr = Fixup.getValue(); 44 45 if (Expr->getKind() != MCExpr::Target) 46 return Target.getAccessVariant(); 47 48 switch (cast<PPCMCExpr>(Expr)->getKind()) { 49 case PPCMCExpr::VK_PPC_None: 50 return MCSymbolRefExpr::VK_None; 51 case PPCMCExpr::VK_PPC_LO: 52 return MCSymbolRefExpr::VK_PPC_LO; 53 case PPCMCExpr::VK_PPC_HI: 54 return MCSymbolRefExpr::VK_PPC_HI; 55 case PPCMCExpr::VK_PPC_HA: 56 return MCSymbolRefExpr::VK_PPC_HA; 57 case PPCMCExpr::VK_PPC_HIGH: 58 return MCSymbolRefExpr::VK_PPC_HIGH; 59 case PPCMCExpr::VK_PPC_HIGHA: 60 return MCSymbolRefExpr::VK_PPC_HIGHA; 61 case PPCMCExpr::VK_PPC_HIGHERA: 62 return MCSymbolRefExpr::VK_PPC_HIGHERA; 63 case PPCMCExpr::VK_PPC_HIGHER: 64 return MCSymbolRefExpr::VK_PPC_HIGHER; 65 case PPCMCExpr::VK_PPC_HIGHEST: 66 return MCSymbolRefExpr::VK_PPC_HIGHEST; 67 case PPCMCExpr::VK_PPC_HIGHESTA: 68 return MCSymbolRefExpr::VK_PPC_HIGHESTA; 69 } 70 llvm_unreachable("unknown PPCMCExpr kind"); 71 } 72 73 unsigned PPCELFObjectWriter::getRelocType(MCContext &Ctx, const MCValue &Target, 74 const MCFixup &Fixup, 75 bool IsPCRel) const { 76 MCFixupKind Kind = Fixup.getKind(); 77 if (Kind >= FirstLiteralRelocationKind) 78 return Kind - FirstLiteralRelocationKind; 79 MCSymbolRefExpr::VariantKind Modifier = getAccessVariant(Target, Fixup); 80 81 // determine the type of the relocation 82 unsigned Type; 83 if (IsPCRel) { 84 switch (Fixup.getTargetKind()) { 85 default: 86 llvm_unreachable("Unimplemented"); 87 case PPC::fixup_ppc_br24: 88 case PPC::fixup_ppc_br24abs: 89 case PPC::fixup_ppc_br24_notoc: 90 switch (Modifier) { 91 default: llvm_unreachable("Unsupported Modifier"); 92 case MCSymbolRefExpr::VK_None: 93 Type = ELF::R_PPC_REL24; 94 break; 95 case MCSymbolRefExpr::VK_PLT: 96 Type = ELF::R_PPC_PLTREL24; 97 break; 98 case MCSymbolRefExpr::VK_PPC_LOCAL: 99 Type = ELF::R_PPC_LOCAL24PC; 100 break; 101 case MCSymbolRefExpr::VK_PPC_NOTOC: 102 Type = ELF::R_PPC64_REL24_NOTOC; 103 break; 104 } 105 break; 106 case PPC::fixup_ppc_brcond14: 107 case PPC::fixup_ppc_brcond14abs: 108 Type = ELF::R_PPC_REL14; 109 break; 110 case PPC::fixup_ppc_half16: 111 switch (Modifier) { 112 default: llvm_unreachable("Unsupported Modifier"); 113 case MCSymbolRefExpr::VK_None: 114 Type = ELF::R_PPC_REL16; 115 break; 116 case MCSymbolRefExpr::VK_PPC_LO: 117 Type = ELF::R_PPC_REL16_LO; 118 break; 119 case MCSymbolRefExpr::VK_PPC_HI: 120 Type = ELF::R_PPC_REL16_HI; 121 break; 122 case MCSymbolRefExpr::VK_PPC_HA: 123 Type = ELF::R_PPC_REL16_HA; 124 break; 125 } 126 break; 127 case PPC::fixup_ppc_half16ds: 128 Target.print(errs()); 129 errs() << '\n'; 130 report_fatal_error("Invalid PC-relative half16ds relocation"); 131 case PPC::fixup_ppc_pcrel34: 132 switch (Modifier) { 133 default: 134 llvm_unreachable("Unsupported Modifier for fixup_ppc_pcrel34"); 135 case MCSymbolRefExpr::VK_PCREL: 136 Type = ELF::R_PPC64_PCREL34; 137 break; 138 case MCSymbolRefExpr::VK_PPC_GOT_PCREL: 139 Type = ELF::R_PPC64_GOT_PCREL34; 140 break; 141 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_PCREL: 142 Type = ELF::R_PPC64_GOT_TLSGD_PCREL34; 143 break; 144 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_PCREL: 145 Type = ELF::R_PPC64_GOT_TLSLD_PCREL34; 146 break; 147 case MCSymbolRefExpr::VK_PPC_GOT_TPREL_PCREL: 148 Type = ELF::R_PPC64_GOT_TPREL_PCREL34; 149 break; 150 } 151 break; 152 case FK_Data_4: 153 case FK_PCRel_4: 154 Type = ELF::R_PPC_REL32; 155 break; 156 case FK_Data_8: 157 case FK_PCRel_8: 158 Type = ELF::R_PPC64_REL64; 159 break; 160 } 161 } else { 162 switch (Fixup.getTargetKind()) { 163 default: llvm_unreachable("invalid fixup kind!"); 164 case PPC::fixup_ppc_br24abs: 165 Type = ELF::R_PPC_ADDR24; 166 break; 167 case PPC::fixup_ppc_brcond14abs: 168 Type = ELF::R_PPC_ADDR14; // XXX: or BRNTAKEN?_ 169 break; 170 case PPC::fixup_ppc_half16: 171 switch (Modifier) { 172 default: llvm_unreachable("Unsupported Modifier"); 173 case MCSymbolRefExpr::VK_None: 174 Type = ELF::R_PPC_ADDR16; 175 break; 176 case MCSymbolRefExpr::VK_PPC_LO: 177 Type = ELF::R_PPC_ADDR16_LO; 178 break; 179 case MCSymbolRefExpr::VK_PPC_HI: 180 Type = ELF::R_PPC_ADDR16_HI; 181 break; 182 case MCSymbolRefExpr::VK_PPC_HA: 183 Type = ELF::R_PPC_ADDR16_HA; 184 break; 185 case MCSymbolRefExpr::VK_PPC_HIGH: 186 Type = ELF::R_PPC64_ADDR16_HIGH; 187 break; 188 case MCSymbolRefExpr::VK_PPC_HIGHA: 189 Type = ELF::R_PPC64_ADDR16_HIGHA; 190 break; 191 case MCSymbolRefExpr::VK_PPC_HIGHER: 192 Type = ELF::R_PPC64_ADDR16_HIGHER; 193 break; 194 case MCSymbolRefExpr::VK_PPC_HIGHERA: 195 Type = ELF::R_PPC64_ADDR16_HIGHERA; 196 break; 197 case MCSymbolRefExpr::VK_PPC_HIGHEST: 198 Type = ELF::R_PPC64_ADDR16_HIGHEST; 199 break; 200 case MCSymbolRefExpr::VK_PPC_HIGHESTA: 201 Type = ELF::R_PPC64_ADDR16_HIGHESTA; 202 break; 203 case MCSymbolRefExpr::VK_GOT: 204 Type = ELF::R_PPC_GOT16; 205 break; 206 case MCSymbolRefExpr::VK_PPC_GOT_LO: 207 Type = ELF::R_PPC_GOT16_LO; 208 break; 209 case MCSymbolRefExpr::VK_PPC_GOT_HI: 210 Type = ELF::R_PPC_GOT16_HI; 211 break; 212 case MCSymbolRefExpr::VK_PPC_GOT_HA: 213 Type = ELF::R_PPC_GOT16_HA; 214 break; 215 case MCSymbolRefExpr::VK_PPC_TOC: 216 Type = ELF::R_PPC64_TOC16; 217 break; 218 case MCSymbolRefExpr::VK_PPC_TOC_LO: 219 Type = ELF::R_PPC64_TOC16_LO; 220 break; 221 case MCSymbolRefExpr::VK_PPC_TOC_HI: 222 Type = ELF::R_PPC64_TOC16_HI; 223 break; 224 case MCSymbolRefExpr::VK_PPC_TOC_HA: 225 Type = ELF::R_PPC64_TOC16_HA; 226 break; 227 case MCSymbolRefExpr::VK_TPREL: 228 Type = ELF::R_PPC_TPREL16; 229 break; 230 case MCSymbolRefExpr::VK_PPC_TPREL_LO: 231 Type = ELF::R_PPC_TPREL16_LO; 232 break; 233 case MCSymbolRefExpr::VK_PPC_TPREL_HI: 234 Type = ELF::R_PPC_TPREL16_HI; 235 break; 236 case MCSymbolRefExpr::VK_PPC_TPREL_HA: 237 Type = ELF::R_PPC_TPREL16_HA; 238 break; 239 case MCSymbolRefExpr::VK_PPC_TPREL_HIGH: 240 Type = ELF::R_PPC64_TPREL16_HIGH; 241 break; 242 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHA: 243 Type = ELF::R_PPC64_TPREL16_HIGHA; 244 break; 245 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHER: 246 Type = ELF::R_PPC64_TPREL16_HIGHER; 247 break; 248 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHERA: 249 Type = ELF::R_PPC64_TPREL16_HIGHERA; 250 break; 251 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHEST: 252 Type = ELF::R_PPC64_TPREL16_HIGHEST; 253 break; 254 case MCSymbolRefExpr::VK_PPC_TPREL_HIGHESTA: 255 Type = ELF::R_PPC64_TPREL16_HIGHESTA; 256 break; 257 case MCSymbolRefExpr::VK_DTPREL: 258 Type = ELF::R_PPC64_DTPREL16; 259 break; 260 case MCSymbolRefExpr::VK_PPC_DTPREL_LO: 261 Type = ELF::R_PPC64_DTPREL16_LO; 262 break; 263 case MCSymbolRefExpr::VK_PPC_DTPREL_HI: 264 Type = ELF::R_PPC64_DTPREL16_HI; 265 break; 266 case MCSymbolRefExpr::VK_PPC_DTPREL_HA: 267 Type = ELF::R_PPC64_DTPREL16_HA; 268 break; 269 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGH: 270 Type = ELF::R_PPC64_DTPREL16_HIGH; 271 break; 272 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHA: 273 Type = ELF::R_PPC64_DTPREL16_HIGHA; 274 break; 275 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHER: 276 Type = ELF::R_PPC64_DTPREL16_HIGHER; 277 break; 278 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHERA: 279 Type = ELF::R_PPC64_DTPREL16_HIGHERA; 280 break; 281 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHEST: 282 Type = ELF::R_PPC64_DTPREL16_HIGHEST; 283 break; 284 case MCSymbolRefExpr::VK_PPC_DTPREL_HIGHESTA: 285 Type = ELF::R_PPC64_DTPREL16_HIGHESTA; 286 break; 287 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD: 288 if (is64Bit()) 289 Type = ELF::R_PPC64_GOT_TLSGD16; 290 else 291 Type = ELF::R_PPC_GOT_TLSGD16; 292 break; 293 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_LO: 294 Type = ELF::R_PPC64_GOT_TLSGD16_LO; 295 break; 296 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HI: 297 Type = ELF::R_PPC64_GOT_TLSGD16_HI; 298 break; 299 case MCSymbolRefExpr::VK_PPC_GOT_TLSGD_HA: 300 Type = ELF::R_PPC64_GOT_TLSGD16_HA; 301 break; 302 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD: 303 if (is64Bit()) 304 Type = ELF::R_PPC64_GOT_TLSLD16; 305 else 306 Type = ELF::R_PPC_GOT_TLSLD16; 307 break; 308 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_LO: 309 Type = ELF::R_PPC64_GOT_TLSLD16_LO; 310 break; 311 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HI: 312 Type = ELF::R_PPC64_GOT_TLSLD16_HI; 313 break; 314 case MCSymbolRefExpr::VK_PPC_GOT_TLSLD_HA: 315 Type = ELF::R_PPC64_GOT_TLSLD16_HA; 316 break; 317 case MCSymbolRefExpr::VK_PPC_GOT_TPREL: 318 /* We don't have R_PPC64_GOT_TPREL16, but since GOT offsets 319 are always 4-aligned, we can use R_PPC64_GOT_TPREL16_DS. */ 320 Type = ELF::R_PPC64_GOT_TPREL16_DS; 321 break; 322 case MCSymbolRefExpr::VK_PPC_GOT_TPREL_LO: 323 /* We don't have R_PPC64_GOT_TPREL16_LO, but since GOT offsets 324 are always 4-aligned, we can use R_PPC64_GOT_TPREL16_LO_DS. */ 325 Type = ELF::R_PPC64_GOT_TPREL16_LO_DS; 326 break; 327 case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HI: 328 Type = ELF::R_PPC64_GOT_TPREL16_HI; 329 break; 330 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL: 331 /* We don't have R_PPC64_GOT_DTPREL16, but since GOT offsets 332 are always 4-aligned, we can use R_PPC64_GOT_DTPREL16_DS. */ 333 Type = ELF::R_PPC64_GOT_DTPREL16_DS; 334 break; 335 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_LO: 336 /* We don't have R_PPC64_GOT_DTPREL16_LO, but since GOT offsets 337 are always 4-aligned, we can use R_PPC64_GOT_DTPREL16_LO_DS. */ 338 Type = ELF::R_PPC64_GOT_DTPREL16_LO_DS; 339 break; 340 case MCSymbolRefExpr::VK_PPC_GOT_TPREL_HA: 341 Type = ELF::R_PPC64_GOT_TPREL16_HA; 342 break; 343 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HI: 344 Type = ELF::R_PPC64_GOT_DTPREL16_HI; 345 break; 346 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_HA: 347 Type = ELF::R_PPC64_GOT_DTPREL16_HA; 348 break; 349 } 350 break; 351 case PPC::fixup_ppc_half16ds: 352 switch (Modifier) { 353 default: llvm_unreachable("Unsupported Modifier"); 354 case MCSymbolRefExpr::VK_None: 355 Type = ELF::R_PPC64_ADDR16_DS; 356 break; 357 case MCSymbolRefExpr::VK_PPC_LO: 358 Type = ELF::R_PPC64_ADDR16_LO_DS; 359 break; 360 case MCSymbolRefExpr::VK_GOT: 361 Type = ELF::R_PPC64_GOT16_DS; 362 break; 363 case MCSymbolRefExpr::VK_PPC_GOT_LO: 364 Type = ELF::R_PPC64_GOT16_LO_DS; 365 break; 366 case MCSymbolRefExpr::VK_PPC_TOC: 367 Type = ELF::R_PPC64_TOC16_DS; 368 break; 369 case MCSymbolRefExpr::VK_PPC_TOC_LO: 370 Type = ELF::R_PPC64_TOC16_LO_DS; 371 break; 372 case MCSymbolRefExpr::VK_TPREL: 373 Type = ELF::R_PPC64_TPREL16_DS; 374 break; 375 case MCSymbolRefExpr::VK_PPC_TPREL_LO: 376 Type = ELF::R_PPC64_TPREL16_LO_DS; 377 break; 378 case MCSymbolRefExpr::VK_DTPREL: 379 Type = ELF::R_PPC64_DTPREL16_DS; 380 break; 381 case MCSymbolRefExpr::VK_PPC_DTPREL_LO: 382 Type = ELF::R_PPC64_DTPREL16_LO_DS; 383 break; 384 case MCSymbolRefExpr::VK_PPC_GOT_TPREL: 385 Type = ELF::R_PPC64_GOT_TPREL16_DS; 386 break; 387 case MCSymbolRefExpr::VK_PPC_GOT_TPREL_LO: 388 Type = ELF::R_PPC64_GOT_TPREL16_LO_DS; 389 break; 390 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL: 391 Type = ELF::R_PPC64_GOT_DTPREL16_DS; 392 break; 393 case MCSymbolRefExpr::VK_PPC_GOT_DTPREL_LO: 394 Type = ELF::R_PPC64_GOT_DTPREL16_LO_DS; 395 break; 396 } 397 break; 398 case PPC::fixup_ppc_nofixup: 399 switch (Modifier) { 400 default: llvm_unreachable("Unsupported Modifier"); 401 case MCSymbolRefExpr::VK_PPC_TLSGD: 402 if (is64Bit()) 403 Type = ELF::R_PPC64_TLSGD; 404 else 405 Type = ELF::R_PPC_TLSGD; 406 break; 407 case MCSymbolRefExpr::VK_PPC_TLSLD: 408 if (is64Bit()) 409 Type = ELF::R_PPC64_TLSLD; 410 else 411 Type = ELF::R_PPC_TLSLD; 412 break; 413 case MCSymbolRefExpr::VK_PPC_TLS: 414 if (is64Bit()) 415 Type = ELF::R_PPC64_TLS; 416 else 417 Type = ELF::R_PPC_TLS; 418 break; 419 case MCSymbolRefExpr::VK_PPC_TLS_PCREL: 420 Type = ELF::R_PPC64_TLS; 421 break; 422 } 423 break; 424 case PPC::fixup_ppc_imm34: 425 switch (Modifier) { 426 default: 427 report_fatal_error("Unsupported Modifier for fixup_ppc_imm34."); 428 case MCSymbolRefExpr::VK_DTPREL: 429 Type = ELF::R_PPC64_DTPREL34; 430 break; 431 case MCSymbolRefExpr::VK_TPREL: 432 Type = ELF::R_PPC64_TPREL34; 433 break; 434 } 435 break; 436 case FK_Data_8: 437 switch (Modifier) { 438 default: llvm_unreachable("Unsupported Modifier"); 439 case MCSymbolRefExpr::VK_PPC_TOCBASE: 440 Type = ELF::R_PPC64_TOC; 441 break; 442 case MCSymbolRefExpr::VK_None: 443 Type = ELF::R_PPC64_ADDR64; 444 break; 445 case MCSymbolRefExpr::VK_PPC_DTPMOD: 446 Type = ELF::R_PPC64_DTPMOD64; 447 break; 448 case MCSymbolRefExpr::VK_TPREL: 449 Type = ELF::R_PPC64_TPREL64; 450 break; 451 case MCSymbolRefExpr::VK_DTPREL: 452 Type = ELF::R_PPC64_DTPREL64; 453 break; 454 } 455 break; 456 case FK_Data_4: 457 Type = ELF::R_PPC_ADDR32; 458 break; 459 case FK_Data_2: 460 Type = ELF::R_PPC_ADDR16; 461 break; 462 } 463 } 464 return Type; 465 } 466 467 bool PPCELFObjectWriter::needsRelocateWithSymbol(const MCSymbol &Sym, 468 unsigned Type) const { 469 switch (Type) { 470 default: 471 return false; 472 473 case ELF::R_PPC_REL24: 474 case ELF::R_PPC64_REL24_NOTOC: 475 // If the target symbol has a local entry point, we must keep the 476 // target symbol to preserve that information for the linker. 477 // The "other" values are stored in the last 6 bits of the second byte. 478 // The traditional defines for STO values assume the full byte and thus 479 // the shift to pack it. 480 unsigned Other = cast<MCSymbolELF>(Sym).getOther() << 2; 481 return (Other & ELF::STO_PPC64_LOCAL_MASK) != 0; 482 } 483 } 484 485 std::unique_ptr<MCObjectTargetWriter> 486 llvm::createPPCELFObjectWriter(bool Is64Bit, uint8_t OSABI) { 487 return std::make_unique<PPCELFObjectWriter>(Is64Bit, OSABI); 488 } 489