1 //===-- MCObjectFileInfo.cpp - Object File Information --------------------===// 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 "llvm/MC/MCObjectFileInfo.h" 11 #include "llvm/ADT/StringExtras.h" 12 #include "llvm/ADT/Triple.h" 13 #include "llvm/MC/MCAsmInfo.h" 14 #include "llvm/MC/MCContext.h" 15 #include "llvm/MC/MCSection.h" 16 #include "llvm/MC/MCSectionCOFF.h" 17 #include "llvm/MC/MCSectionELF.h" 18 #include "llvm/MC/MCSectionMachO.h" 19 #include "llvm/Support/COFF.h" 20 #include "llvm/Support/ELF.h" 21 22 using namespace llvm; 23 24 static bool useCompactUnwind(const Triple &T) { 25 // Only on darwin. 26 if (!T.isOSDarwin()) 27 return false; 28 29 // aarch64 always has it. 30 if (T.getArch() == Triple::aarch64) 31 return true; 32 33 // armv7k always has it. 34 if (T.isWatchABI()) 35 return true; 36 37 // Use it on newer version of OS X. 38 if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6)) 39 return true; 40 41 // And the iOS simulator. 42 if (T.isiOS() && 43 (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86)) 44 return true; 45 46 return false; 47 } 48 49 void MCObjectFileInfo::initMachOMCObjectFileInfo(const Triple &T) { 50 // MachO 51 SupportsWeakOmittedEHFrame = false; 52 53 EHFrameSection = Ctx->getMachOSection( 54 "__TEXT", "__eh_frame", 55 MachO::S_COALESCED | MachO::S_ATTR_NO_TOC | 56 MachO::S_ATTR_STRIP_STATIC_SYMS | MachO::S_ATTR_LIVE_SUPPORT, 57 SectionKind::getReadOnly()); 58 59 if (T.isOSDarwin() && T.getArch() == Triple::aarch64) 60 SupportsCompactUnwindWithoutEHFrame = true; 61 62 if (T.isWatchABI()) 63 OmitDwarfIfHaveCompactUnwind = true; 64 65 PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel 66 | dwarf::DW_EH_PE_sdata4; 67 LSDAEncoding = FDECFIEncoding = dwarf::DW_EH_PE_pcrel; 68 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | 69 dwarf::DW_EH_PE_sdata4; 70 71 // .comm doesn't support alignment before Leopard. 72 if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5)) 73 CommDirectiveSupportsAlignment = false; 74 75 TextSection // .text 76 = Ctx->getMachOSection("__TEXT", "__text", 77 MachO::S_ATTR_PURE_INSTRUCTIONS, 78 SectionKind::getText()); 79 DataSection // .data 80 = Ctx->getMachOSection("__DATA", "__data", 0, SectionKind::getData()); 81 82 // BSSSection might not be expected initialized on msvc. 83 BSSSection = nullptr; 84 85 TLSDataSection // .tdata 86 = Ctx->getMachOSection("__DATA", "__thread_data", 87 MachO::S_THREAD_LOCAL_REGULAR, 88 SectionKind::getData()); 89 TLSBSSSection // .tbss 90 = Ctx->getMachOSection("__DATA", "__thread_bss", 91 MachO::S_THREAD_LOCAL_ZEROFILL, 92 SectionKind::getThreadBSS()); 93 94 // TODO: Verify datarel below. 95 TLSTLVSection // .tlv 96 = Ctx->getMachOSection("__DATA", "__thread_vars", 97 MachO::S_THREAD_LOCAL_VARIABLES, 98 SectionKind::getData()); 99 100 TLSThreadInitSection = Ctx->getMachOSection( 101 "__DATA", "__thread_init", MachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS, 102 SectionKind::getData()); 103 104 CStringSection // .cstring 105 = Ctx->getMachOSection("__TEXT", "__cstring", 106 MachO::S_CSTRING_LITERALS, 107 SectionKind::getMergeable1ByteCString()); 108 UStringSection 109 = Ctx->getMachOSection("__TEXT","__ustring", 0, 110 SectionKind::getMergeable2ByteCString()); 111 FourByteConstantSection // .literal4 112 = Ctx->getMachOSection("__TEXT", "__literal4", 113 MachO::S_4BYTE_LITERALS, 114 SectionKind::getMergeableConst4()); 115 EightByteConstantSection // .literal8 116 = Ctx->getMachOSection("__TEXT", "__literal8", 117 MachO::S_8BYTE_LITERALS, 118 SectionKind::getMergeableConst8()); 119 120 SixteenByteConstantSection // .literal16 121 = Ctx->getMachOSection("__TEXT", "__literal16", 122 MachO::S_16BYTE_LITERALS, 123 SectionKind::getMergeableConst16()); 124 125 ReadOnlySection // .const 126 = Ctx->getMachOSection("__TEXT", "__const", 0, 127 SectionKind::getReadOnly()); 128 129 // If the target is not powerpc, map the coal sections to the non-coal 130 // sections. 131 // 132 // "__TEXT/__textcoal_nt" => section "__TEXT/__text" 133 // "__TEXT/__const_coal" => section "__TEXT/__const" 134 // "__DATA/__datacoal_nt" => section "__DATA/__data" 135 Triple::ArchType ArchTy = T.getArch(); 136 137 if (ArchTy == Triple::ppc || ArchTy == Triple::ppc64) { 138 TextCoalSection 139 = Ctx->getMachOSection("__TEXT", "__textcoal_nt", 140 MachO::S_COALESCED | 141 MachO::S_ATTR_PURE_INSTRUCTIONS, 142 SectionKind::getText()); 143 ConstTextCoalSection 144 = Ctx->getMachOSection("__TEXT", "__const_coal", 145 MachO::S_COALESCED, 146 SectionKind::getReadOnly()); 147 DataCoalSection = Ctx->getMachOSection( 148 "__DATA", "__datacoal_nt", MachO::S_COALESCED, SectionKind::getData()); 149 } else { 150 TextCoalSection = TextSection; 151 ConstTextCoalSection = ReadOnlySection; 152 DataCoalSection = DataSection; 153 } 154 155 ConstDataSection // .const_data 156 = Ctx->getMachOSection("__DATA", "__const", 0, 157 SectionKind::getReadOnlyWithRel()); 158 DataCommonSection 159 = Ctx->getMachOSection("__DATA","__common", 160 MachO::S_ZEROFILL, 161 SectionKind::getBSS()); 162 DataBSSSection 163 = Ctx->getMachOSection("__DATA","__bss", MachO::S_ZEROFILL, 164 SectionKind::getBSS()); 165 166 167 LazySymbolPointerSection 168 = Ctx->getMachOSection("__DATA", "__la_symbol_ptr", 169 MachO::S_LAZY_SYMBOL_POINTERS, 170 SectionKind::getMetadata()); 171 NonLazySymbolPointerSection 172 = Ctx->getMachOSection("__DATA", "__nl_symbol_ptr", 173 MachO::S_NON_LAZY_SYMBOL_POINTERS, 174 SectionKind::getMetadata()); 175 176 ThreadLocalPointerSection 177 = Ctx->getMachOSection("__DATA", "__thread_ptr", 178 MachO::S_THREAD_LOCAL_VARIABLE_POINTERS, 179 SectionKind::getMetadata()); 180 181 // Exception Handling. 182 LSDASection = Ctx->getMachOSection("__TEXT", "__gcc_except_tab", 0, 183 SectionKind::getReadOnlyWithRel()); 184 185 COFFDebugSymbolsSection = nullptr; 186 COFFDebugTypesSection = nullptr; 187 188 if (useCompactUnwind(T)) { 189 CompactUnwindSection = 190 Ctx->getMachOSection("__LD", "__compact_unwind", MachO::S_ATTR_DEBUG, 191 SectionKind::getReadOnly()); 192 193 if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86) 194 CompactUnwindDwarfEHFrameOnly = 0x04000000; // UNWIND_X86_64_MODE_DWARF 195 else if (T.getArch() == Triple::aarch64) 196 CompactUnwindDwarfEHFrameOnly = 0x03000000; // UNWIND_ARM64_MODE_DWARF 197 else if (T.getArch() == Triple::arm || T.getArch() == Triple::thumb) 198 CompactUnwindDwarfEHFrameOnly = 0x04000000; // UNWIND_ARM_MODE_DWARF 199 } 200 201 // Debug Information. 202 DwarfAccelNamesSection = 203 Ctx->getMachOSection("__DWARF", "__apple_names", MachO::S_ATTR_DEBUG, 204 SectionKind::getMetadata(), "names_begin"); 205 DwarfAccelObjCSection = 206 Ctx->getMachOSection("__DWARF", "__apple_objc", MachO::S_ATTR_DEBUG, 207 SectionKind::getMetadata(), "objc_begin"); 208 // 16 character section limit... 209 DwarfAccelNamespaceSection = 210 Ctx->getMachOSection("__DWARF", "__apple_namespac", MachO::S_ATTR_DEBUG, 211 SectionKind::getMetadata(), "namespac_begin"); 212 DwarfAccelTypesSection = 213 Ctx->getMachOSection("__DWARF", "__apple_types", MachO::S_ATTR_DEBUG, 214 SectionKind::getMetadata(), "types_begin"); 215 216 DwarfAbbrevSection = 217 Ctx->getMachOSection("__DWARF", "__debug_abbrev", MachO::S_ATTR_DEBUG, 218 SectionKind::getMetadata(), "section_abbrev"); 219 DwarfInfoSection = 220 Ctx->getMachOSection("__DWARF", "__debug_info", MachO::S_ATTR_DEBUG, 221 SectionKind::getMetadata(), "section_info"); 222 DwarfLineSection = 223 Ctx->getMachOSection("__DWARF", "__debug_line", MachO::S_ATTR_DEBUG, 224 SectionKind::getMetadata(), "section_line"); 225 DwarfFrameSection = 226 Ctx->getMachOSection("__DWARF", "__debug_frame", MachO::S_ATTR_DEBUG, 227 SectionKind::getMetadata()); 228 DwarfPubNamesSection = 229 Ctx->getMachOSection("__DWARF", "__debug_pubnames", MachO::S_ATTR_DEBUG, 230 SectionKind::getMetadata()); 231 DwarfPubTypesSection = 232 Ctx->getMachOSection("__DWARF", "__debug_pubtypes", MachO::S_ATTR_DEBUG, 233 SectionKind::getMetadata()); 234 DwarfGnuPubNamesSection = 235 Ctx->getMachOSection("__DWARF", "__debug_gnu_pubn", MachO::S_ATTR_DEBUG, 236 SectionKind::getMetadata()); 237 DwarfGnuPubTypesSection = 238 Ctx->getMachOSection("__DWARF", "__debug_gnu_pubt", MachO::S_ATTR_DEBUG, 239 SectionKind::getMetadata()); 240 DwarfStrSection = 241 Ctx->getMachOSection("__DWARF", "__debug_str", MachO::S_ATTR_DEBUG, 242 SectionKind::getMetadata(), "info_string"); 243 DwarfLocSection = 244 Ctx->getMachOSection("__DWARF", "__debug_loc", MachO::S_ATTR_DEBUG, 245 SectionKind::getMetadata(), "section_debug_loc"); 246 DwarfARangesSection = 247 Ctx->getMachOSection("__DWARF", "__debug_aranges", MachO::S_ATTR_DEBUG, 248 SectionKind::getMetadata()); 249 DwarfRangesSection = 250 Ctx->getMachOSection("__DWARF", "__debug_ranges", MachO::S_ATTR_DEBUG, 251 SectionKind::getMetadata(), "debug_range"); 252 DwarfMacinfoSection = 253 Ctx->getMachOSection("__DWARF", "__debug_macinfo", MachO::S_ATTR_DEBUG, 254 SectionKind::getMetadata(), "debug_macinfo"); 255 DwarfDebugInlineSection = 256 Ctx->getMachOSection("__DWARF", "__debug_inlined", MachO::S_ATTR_DEBUG, 257 SectionKind::getMetadata()); 258 DwarfCUIndexSection = 259 Ctx->getMachOSection("__DWARF", "__debug_cu_index", MachO::S_ATTR_DEBUG, 260 SectionKind::getMetadata()); 261 DwarfTUIndexSection = 262 Ctx->getMachOSection("__DWARF", "__debug_tu_index", MachO::S_ATTR_DEBUG, 263 SectionKind::getMetadata()); 264 StackMapSection = Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps", 265 0, SectionKind::getMetadata()); 266 267 FaultMapSection = Ctx->getMachOSection("__LLVM_FAULTMAPS", "__llvm_faultmaps", 268 0, SectionKind::getMetadata()); 269 270 TLSExtraDataSection = TLSTLVSection; 271 } 272 273 void MCObjectFileInfo::initELFMCObjectFileInfo(const Triple &T) { 274 switch (T.getArch()) { 275 case Triple::mips: 276 case Triple::mipsel: 277 FDECFIEncoding = dwarf::DW_EH_PE_sdata4; 278 break; 279 case Triple::mips64: 280 case Triple::mips64el: 281 FDECFIEncoding = dwarf::DW_EH_PE_sdata8; 282 break; 283 case Triple::x86_64: 284 FDECFIEncoding = dwarf::DW_EH_PE_pcrel | 285 ((CMModel == CodeModel::Large) ? dwarf::DW_EH_PE_sdata8 286 : dwarf::DW_EH_PE_sdata4); 287 break; 288 default: 289 FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4; 290 break; 291 } 292 293 switch (T.getArch()) { 294 case Triple::arm: 295 case Triple::armeb: 296 case Triple::thumb: 297 case Triple::thumbeb: 298 if (Ctx->getAsmInfo()->getExceptionHandlingType() == ExceptionHandling::ARM) 299 break; 300 // Fallthrough if not using EHABI 301 LLVM_FALLTHROUGH; 302 case Triple::ppc: 303 case Triple::x86: 304 PersonalityEncoding = PositionIndependent 305 ? dwarf::DW_EH_PE_indirect | 306 dwarf::DW_EH_PE_pcrel | 307 dwarf::DW_EH_PE_sdata4 308 : dwarf::DW_EH_PE_absptr; 309 LSDAEncoding = PositionIndependent 310 ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4 311 : dwarf::DW_EH_PE_absptr; 312 TTypeEncoding = PositionIndependent 313 ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | 314 dwarf::DW_EH_PE_sdata4 315 : dwarf::DW_EH_PE_absptr; 316 break; 317 case Triple::x86_64: 318 if (PositionIndependent) { 319 PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | 320 ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium) 321 ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8); 322 LSDAEncoding = dwarf::DW_EH_PE_pcrel | 323 (CMModel == CodeModel::Small 324 ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8); 325 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | 326 ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium) 327 ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8); 328 } else { 329 PersonalityEncoding = 330 (CMModel == CodeModel::Small || CMModel == CodeModel::Medium) 331 ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr; 332 LSDAEncoding = (CMModel == CodeModel::Small) 333 ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr; 334 TTypeEncoding = (CMModel == CodeModel::Small) 335 ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr; 336 } 337 break; 338 case Triple::hexagon: 339 PersonalityEncoding = dwarf::DW_EH_PE_absptr; 340 LSDAEncoding = dwarf::DW_EH_PE_absptr; 341 FDECFIEncoding = dwarf::DW_EH_PE_absptr; 342 TTypeEncoding = dwarf::DW_EH_PE_absptr; 343 if (PositionIndependent) { 344 PersonalityEncoding |= dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel; 345 LSDAEncoding |= dwarf::DW_EH_PE_pcrel; 346 FDECFIEncoding |= dwarf::DW_EH_PE_pcrel; 347 TTypeEncoding |= dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel; 348 } 349 break; 350 case Triple::aarch64: 351 case Triple::aarch64_be: 352 // The small model guarantees static code/data size < 4GB, but not where it 353 // will be in memory. Most of these could end up >2GB away so even a signed 354 // pc-relative 32-bit address is insufficient, theoretically. 355 if (PositionIndependent) { 356 PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | 357 dwarf::DW_EH_PE_sdata8; 358 LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8; 359 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | 360 dwarf::DW_EH_PE_sdata8; 361 } else { 362 PersonalityEncoding = dwarf::DW_EH_PE_absptr; 363 LSDAEncoding = dwarf::DW_EH_PE_absptr; 364 TTypeEncoding = dwarf::DW_EH_PE_absptr; 365 } 366 break; 367 case Triple::lanai: 368 LSDAEncoding = dwarf::DW_EH_PE_absptr; 369 PersonalityEncoding = dwarf::DW_EH_PE_absptr; 370 TTypeEncoding = dwarf::DW_EH_PE_absptr; 371 break; 372 case Triple::mips: 373 case Triple::mipsel: 374 case Triple::mips64: 375 case Triple::mips64el: 376 // MIPS uses indirect pointer to refer personality functions and types, so 377 // that the eh_frame section can be read-only. DW.ref.personality will be 378 // generated for relocation. 379 PersonalityEncoding = dwarf::DW_EH_PE_indirect; 380 // FIXME: The N64 ABI probably ought to use DW_EH_PE_sdata8 but we can't 381 // identify N64 from just a triple. 382 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | 383 dwarf::DW_EH_PE_sdata4; 384 // We don't support PC-relative LSDA references in GAS so we use the default 385 // DW_EH_PE_absptr for those. 386 387 // FreeBSD must be explicit about the data size and using pcrel since it's 388 // assembler/linker won't do the automatic conversion that the Linux tools 389 // do. 390 if (T.isOSFreeBSD()) { 391 PersonalityEncoding |= dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4; 392 LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4; 393 } 394 break; 395 case Triple::ppc64: 396 case Triple::ppc64le: 397 PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | 398 dwarf::DW_EH_PE_udata8; 399 LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8; 400 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | 401 dwarf::DW_EH_PE_udata8; 402 break; 403 case Triple::sparcel: 404 case Triple::sparc: 405 if (PositionIndependent) { 406 LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4; 407 PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | 408 dwarf::DW_EH_PE_sdata4; 409 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | 410 dwarf::DW_EH_PE_sdata4; 411 } else { 412 LSDAEncoding = dwarf::DW_EH_PE_absptr; 413 PersonalityEncoding = dwarf::DW_EH_PE_absptr; 414 TTypeEncoding = dwarf::DW_EH_PE_absptr; 415 } 416 break; 417 case Triple::sparcv9: 418 LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4; 419 if (PositionIndependent) { 420 PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | 421 dwarf::DW_EH_PE_sdata4; 422 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | 423 dwarf::DW_EH_PE_sdata4; 424 } else { 425 PersonalityEncoding = dwarf::DW_EH_PE_absptr; 426 TTypeEncoding = dwarf::DW_EH_PE_absptr; 427 } 428 break; 429 case Triple::systemz: 430 // All currently-defined code models guarantee that 4-byte PC-relative 431 // values will be in range. 432 if (PositionIndependent) { 433 PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | 434 dwarf::DW_EH_PE_sdata4; 435 LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4; 436 TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | 437 dwarf::DW_EH_PE_sdata4; 438 } else { 439 PersonalityEncoding = dwarf::DW_EH_PE_absptr; 440 LSDAEncoding = dwarf::DW_EH_PE_absptr; 441 TTypeEncoding = dwarf::DW_EH_PE_absptr; 442 } 443 break; 444 default: 445 break; 446 } 447 448 unsigned EHSectionType = T.getArch() == Triple::x86_64 449 ? ELF::SHT_X86_64_UNWIND 450 : ELF::SHT_PROGBITS; 451 452 // Solaris requires different flags for .eh_frame to seemingly every other 453 // platform. 454 unsigned EHSectionFlags = ELF::SHF_ALLOC; 455 if (T.isOSSolaris() && T.getArch() != Triple::x86_64) 456 EHSectionFlags |= ELF::SHF_WRITE; 457 458 // ELF 459 BSSSection = Ctx->getELFSection(".bss", ELF::SHT_NOBITS, 460 ELF::SHF_WRITE | ELF::SHF_ALLOC); 461 462 TextSection = Ctx->getELFSection(".text", ELF::SHT_PROGBITS, 463 ELF::SHF_EXECINSTR | ELF::SHF_ALLOC); 464 465 DataSection = Ctx->getELFSection(".data", ELF::SHT_PROGBITS, 466 ELF::SHF_WRITE | ELF::SHF_ALLOC); 467 468 ReadOnlySection = 469 Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS, ELF::SHF_ALLOC); 470 471 TLSDataSection = 472 Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS, 473 ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE); 474 475 TLSBSSSection = Ctx->getELFSection( 476 ".tbss", ELF::SHT_NOBITS, ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE); 477 478 DataRelROSection = Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS, 479 ELF::SHF_ALLOC | ELF::SHF_WRITE); 480 481 MergeableConst4Section = 482 Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS, 483 ELF::SHF_ALLOC | ELF::SHF_MERGE, 4, ""); 484 485 MergeableConst8Section = 486 Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS, 487 ELF::SHF_ALLOC | ELF::SHF_MERGE, 8, ""); 488 489 MergeableConst16Section = 490 Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS, 491 ELF::SHF_ALLOC | ELF::SHF_MERGE, 16, ""); 492 493 MergeableConst32Section = 494 Ctx->getELFSection(".rodata.cst32", ELF::SHT_PROGBITS, 495 ELF::SHF_ALLOC | ELF::SHF_MERGE, 32, ""); 496 497 // Exception Handling Sections. 498 499 // FIXME: We're emitting LSDA info into a readonly section on ELF, even though 500 // it contains relocatable pointers. In PIC mode, this is probably a big 501 // runtime hit for C++ apps. Either the contents of the LSDA need to be 502 // adjusted or this should be a data section. 503 LSDASection = Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS, 504 ELF::SHF_ALLOC); 505 506 COFFDebugSymbolsSection = nullptr; 507 COFFDebugTypesSection = nullptr; 508 509 // Debug Info Sections. 510 DwarfAbbrevSection = 511 Ctx->getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0); 512 DwarfInfoSection = Ctx->getELFSection(".debug_info", ELF::SHT_PROGBITS, 0); 513 DwarfLineSection = Ctx->getELFSection(".debug_line", ELF::SHT_PROGBITS, 0); 514 DwarfFrameSection = Ctx->getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0); 515 DwarfPubNamesSection = 516 Ctx->getELFSection(".debug_pubnames", ELF::SHT_PROGBITS, 0); 517 DwarfPubTypesSection = 518 Ctx->getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0); 519 DwarfGnuPubNamesSection = 520 Ctx->getELFSection(".debug_gnu_pubnames", ELF::SHT_PROGBITS, 0); 521 DwarfGnuPubTypesSection = 522 Ctx->getELFSection(".debug_gnu_pubtypes", ELF::SHT_PROGBITS, 0); 523 DwarfStrSection = 524 Ctx->getELFSection(".debug_str", ELF::SHT_PROGBITS, 525 ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, ""); 526 DwarfLocSection = Ctx->getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0); 527 DwarfARangesSection = 528 Ctx->getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0); 529 DwarfRangesSection = 530 Ctx->getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0); 531 DwarfMacinfoSection = 532 Ctx->getELFSection(".debug_macinfo", ELF::SHT_PROGBITS, 0); 533 534 // DWARF5 Experimental Debug Info 535 536 // Accelerator Tables 537 DwarfAccelNamesSection = 538 Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0); 539 DwarfAccelObjCSection = 540 Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0); 541 DwarfAccelNamespaceSection = 542 Ctx->getELFSection(".apple_namespaces", ELF::SHT_PROGBITS, 0); 543 DwarfAccelTypesSection = 544 Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0); 545 546 // Fission Sections 547 DwarfInfoDWOSection = 548 Ctx->getELFSection(".debug_info.dwo", ELF::SHT_PROGBITS, 0); 549 DwarfTypesDWOSection = 550 Ctx->getELFSection(".debug_types.dwo", ELF::SHT_PROGBITS, 0); 551 DwarfAbbrevDWOSection = 552 Ctx->getELFSection(".debug_abbrev.dwo", ELF::SHT_PROGBITS, 0); 553 DwarfStrDWOSection = 554 Ctx->getELFSection(".debug_str.dwo", ELF::SHT_PROGBITS, 555 ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, ""); 556 DwarfLineDWOSection = 557 Ctx->getELFSection(".debug_line.dwo", ELF::SHT_PROGBITS, 0); 558 DwarfLocDWOSection = 559 Ctx->getELFSection(".debug_loc.dwo", ELF::SHT_PROGBITS, 0); 560 DwarfStrOffDWOSection = 561 Ctx->getELFSection(".debug_str_offsets.dwo", ELF::SHT_PROGBITS, 0); 562 DwarfAddrSection = Ctx->getELFSection(".debug_addr", ELF::SHT_PROGBITS, 0); 563 564 // DWP Sections 565 DwarfCUIndexSection = 566 Ctx->getELFSection(".debug_cu_index", ELF::SHT_PROGBITS, 0); 567 DwarfTUIndexSection = 568 Ctx->getELFSection(".debug_tu_index", ELF::SHT_PROGBITS, 0); 569 570 StackMapSection = 571 Ctx->getELFSection(".llvm_stackmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC); 572 573 FaultMapSection = 574 Ctx->getELFSection(".llvm_faultmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC); 575 576 EHFrameSection = 577 Ctx->getELFSection(".eh_frame", EHSectionType, EHSectionFlags); 578 } 579 580 void MCObjectFileInfo::initCOFFMCObjectFileInfo(const Triple &T) { 581 EHFrameSection = Ctx->getCOFFSection( 582 ".eh_frame", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 583 COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE, 584 SectionKind::getData()); 585 586 // Set the `IMAGE_SCN_MEM_16BIT` flag when compiling for thumb mode. This is 587 // used to indicate to the linker that the text segment contains thumb instructions 588 // and to set the ISA selection bit for calls accordingly. 589 const bool IsThumb = T.getArch() == Triple::thumb; 590 591 CommDirectiveSupportsAlignment = true; 592 593 // COFF 594 BSSSection = Ctx->getCOFFSection( 595 ".bss", COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA | 596 COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE, 597 SectionKind::getBSS()); 598 TextSection = Ctx->getCOFFSection( 599 ".text", 600 (IsThumb ? COFF::IMAGE_SCN_MEM_16BIT : (COFF::SectionCharacteristics)0) | 601 COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE | 602 COFF::IMAGE_SCN_MEM_READ, 603 SectionKind::getText()); 604 DataSection = Ctx->getCOFFSection( 605 ".data", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ | 606 COFF::IMAGE_SCN_MEM_WRITE, 607 SectionKind::getData()); 608 ReadOnlySection = Ctx->getCOFFSection( 609 ".rdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ, 610 SectionKind::getReadOnly()); 611 612 // FIXME: We're emitting LSDA info into a readonly section on COFF, even 613 // though it contains relocatable pointers. In PIC mode, this is probably a 614 // big runtime hit for C++ apps. Either the contents of the LSDA need to be 615 // adjusted or this should be a data section. 616 if (T.getArch() == Triple::x86_64) { 617 // On Windows 64 with SEH, the LSDA is emitted into the .xdata section 618 LSDASection = nullptr; 619 } else { 620 LSDASection = Ctx->getCOFFSection(".gcc_except_table", 621 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 622 COFF::IMAGE_SCN_MEM_READ, 623 SectionKind::getReadOnly()); 624 } 625 626 // Debug info. 627 COFFDebugSymbolsSection = 628 Ctx->getCOFFSection(".debug$S", (COFF::IMAGE_SCN_MEM_DISCARDABLE | 629 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 630 COFF::IMAGE_SCN_MEM_READ), 631 SectionKind::getMetadata()); 632 COFFDebugTypesSection = 633 Ctx->getCOFFSection(".debug$T", (COFF::IMAGE_SCN_MEM_DISCARDABLE | 634 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 635 COFF::IMAGE_SCN_MEM_READ), 636 SectionKind::getMetadata()); 637 638 DwarfAbbrevSection = Ctx->getCOFFSection( 639 ".debug_abbrev", 640 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 641 COFF::IMAGE_SCN_MEM_READ, 642 SectionKind::getMetadata(), "section_abbrev"); 643 DwarfInfoSection = Ctx->getCOFFSection( 644 ".debug_info", 645 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 646 COFF::IMAGE_SCN_MEM_READ, 647 SectionKind::getMetadata(), "section_info"); 648 DwarfLineSection = Ctx->getCOFFSection( 649 ".debug_line", 650 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 651 COFF::IMAGE_SCN_MEM_READ, 652 SectionKind::getMetadata(), "section_line"); 653 654 DwarfFrameSection = Ctx->getCOFFSection( 655 ".debug_frame", 656 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 657 COFF::IMAGE_SCN_MEM_READ, 658 SectionKind::getMetadata()); 659 DwarfPubNamesSection = Ctx->getCOFFSection( 660 ".debug_pubnames", 661 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 662 COFF::IMAGE_SCN_MEM_READ, 663 SectionKind::getMetadata()); 664 DwarfPubTypesSection = Ctx->getCOFFSection( 665 ".debug_pubtypes", 666 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 667 COFF::IMAGE_SCN_MEM_READ, 668 SectionKind::getMetadata()); 669 DwarfGnuPubNamesSection = Ctx->getCOFFSection( 670 ".debug_gnu_pubnames", 671 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 672 COFF::IMAGE_SCN_MEM_READ, 673 SectionKind::getMetadata()); 674 DwarfGnuPubTypesSection = Ctx->getCOFFSection( 675 ".debug_gnu_pubtypes", 676 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 677 COFF::IMAGE_SCN_MEM_READ, 678 SectionKind::getMetadata()); 679 DwarfStrSection = Ctx->getCOFFSection( 680 ".debug_str", 681 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 682 COFF::IMAGE_SCN_MEM_READ, 683 SectionKind::getMetadata(), "info_string"); 684 DwarfLocSection = Ctx->getCOFFSection( 685 ".debug_loc", 686 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 687 COFF::IMAGE_SCN_MEM_READ, 688 SectionKind::getMetadata(), "section_debug_loc"); 689 DwarfARangesSection = Ctx->getCOFFSection( 690 ".debug_aranges", 691 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 692 COFF::IMAGE_SCN_MEM_READ, 693 SectionKind::getMetadata()); 694 DwarfRangesSection = Ctx->getCOFFSection( 695 ".debug_ranges", 696 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 697 COFF::IMAGE_SCN_MEM_READ, 698 SectionKind::getMetadata(), "debug_range"); 699 DwarfMacinfoSection = Ctx->getCOFFSection( 700 ".debug_macinfo", 701 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 702 COFF::IMAGE_SCN_MEM_READ, 703 SectionKind::getMetadata(), "debug_macinfo"); 704 DwarfInfoDWOSection = Ctx->getCOFFSection( 705 ".debug_info.dwo", 706 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 707 COFF::IMAGE_SCN_MEM_READ, 708 SectionKind::getMetadata(), "section_info_dwo"); 709 DwarfTypesDWOSection = Ctx->getCOFFSection( 710 ".debug_types.dwo", 711 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 712 COFF::IMAGE_SCN_MEM_READ, 713 SectionKind::getMetadata(), "section_types_dwo"); 714 DwarfAbbrevDWOSection = Ctx->getCOFFSection( 715 ".debug_abbrev.dwo", 716 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 717 COFF::IMAGE_SCN_MEM_READ, 718 SectionKind::getMetadata(), "section_abbrev_dwo"); 719 DwarfStrDWOSection = Ctx->getCOFFSection( 720 ".debug_str.dwo", 721 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 722 COFF::IMAGE_SCN_MEM_READ, 723 SectionKind::getMetadata(), "skel_string"); 724 DwarfLineDWOSection = Ctx->getCOFFSection( 725 ".debug_line.dwo", 726 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 727 COFF::IMAGE_SCN_MEM_READ, 728 SectionKind::getMetadata()); 729 DwarfLocDWOSection = Ctx->getCOFFSection( 730 ".debug_loc.dwo", 731 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 732 COFF::IMAGE_SCN_MEM_READ, 733 SectionKind::getMetadata(), "skel_loc"); 734 DwarfStrOffDWOSection = Ctx->getCOFFSection( 735 ".debug_str_offsets.dwo", 736 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 737 COFF::IMAGE_SCN_MEM_READ, 738 SectionKind::getMetadata()); 739 DwarfAddrSection = Ctx->getCOFFSection( 740 ".debug_addr", 741 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 742 COFF::IMAGE_SCN_MEM_READ, 743 SectionKind::getMetadata(), "addr_sec"); 744 DwarfCUIndexSection = Ctx->getCOFFSection( 745 ".debug_cu_index", 746 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 747 COFF::IMAGE_SCN_MEM_READ, 748 SectionKind::getMetadata()); 749 DwarfTUIndexSection = Ctx->getCOFFSection( 750 ".debug_tu_index", 751 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 752 COFF::IMAGE_SCN_MEM_READ, 753 SectionKind::getMetadata()); 754 DwarfAccelNamesSection = Ctx->getCOFFSection( 755 ".apple_names", 756 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 757 COFF::IMAGE_SCN_MEM_READ, 758 SectionKind::getMetadata(), "names_begin"); 759 DwarfAccelNamespaceSection = Ctx->getCOFFSection( 760 ".apple_namespaces", 761 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 762 COFF::IMAGE_SCN_MEM_READ, 763 SectionKind::getMetadata(), "namespac_begin"); 764 DwarfAccelTypesSection = Ctx->getCOFFSection( 765 ".apple_types", 766 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 767 COFF::IMAGE_SCN_MEM_READ, 768 SectionKind::getMetadata(), "types_begin"); 769 DwarfAccelObjCSection = Ctx->getCOFFSection( 770 ".apple_objc", 771 COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 772 COFF::IMAGE_SCN_MEM_READ, 773 SectionKind::getMetadata(), "objc_begin"); 774 775 DrectveSection = Ctx->getCOFFSection( 776 ".drectve", COFF::IMAGE_SCN_LNK_INFO | COFF::IMAGE_SCN_LNK_REMOVE, 777 SectionKind::getMetadata()); 778 779 PDataSection = Ctx->getCOFFSection( 780 ".pdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ, 781 SectionKind::getData()); 782 783 XDataSection = Ctx->getCOFFSection( 784 ".xdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ, 785 SectionKind::getData()); 786 787 SXDataSection = Ctx->getCOFFSection(".sxdata", COFF::IMAGE_SCN_LNK_INFO, 788 SectionKind::getMetadata()); 789 790 TLSDataSection = Ctx->getCOFFSection( 791 ".tls$", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ | 792 COFF::IMAGE_SCN_MEM_WRITE, 793 SectionKind::getData()); 794 795 StackMapSection = Ctx->getCOFFSection(".llvm_stackmaps", 796 COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | 797 COFF::IMAGE_SCN_MEM_READ, 798 SectionKind::getReadOnly()); 799 } 800 801 void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple, bool PIC, 802 CodeModel::Model cm, 803 MCContext &ctx) { 804 PositionIndependent = PIC; 805 CMModel = cm; 806 Ctx = &ctx; 807 808 // Common. 809 CommDirectiveSupportsAlignment = true; 810 SupportsWeakOmittedEHFrame = true; 811 SupportsCompactUnwindWithoutEHFrame = false; 812 OmitDwarfIfHaveCompactUnwind = false; 813 814 PersonalityEncoding = LSDAEncoding = FDECFIEncoding = TTypeEncoding = 815 dwarf::DW_EH_PE_absptr; 816 817 CompactUnwindDwarfEHFrameOnly = 0; 818 819 EHFrameSection = nullptr; // Created on demand. 820 CompactUnwindSection = nullptr; // Used only by selected targets. 821 DwarfAccelNamesSection = nullptr; // Used only by selected targets. 822 DwarfAccelObjCSection = nullptr; // Used only by selected targets. 823 DwarfAccelNamespaceSection = nullptr; // Used only by selected targets. 824 DwarfAccelTypesSection = nullptr; // Used only by selected targets. 825 826 TT = TheTriple; 827 828 switch (TT.getObjectFormat()) { 829 case Triple::MachO: 830 Env = IsMachO; 831 initMachOMCObjectFileInfo(TT); 832 break; 833 case Triple::COFF: 834 if (!TT.isOSWindows()) 835 report_fatal_error( 836 "Cannot initialize MC for non-Windows COFF object files."); 837 838 Env = IsCOFF; 839 initCOFFMCObjectFileInfo(TT); 840 break; 841 case Triple::ELF: 842 Env = IsELF; 843 initELFMCObjectFileInfo(TT); 844 break; 845 case Triple::Wasm: 846 report_fatal_error("Cannot initialize MC for wasm object file format yet."); 847 break; 848 case Triple::UnknownObjectFormat: 849 report_fatal_error("Cannot initialize MC for unknown object file format."); 850 break; 851 } 852 } 853 854 MCSection *MCObjectFileInfo::getDwarfTypesSection(uint64_t Hash) const { 855 return Ctx->getELFSection(".debug_types", ELF::SHT_PROGBITS, ELF::SHF_GROUP, 856 0, utostr(Hash)); 857 } 858