lib/MC/MCObjectFileInfo.cpp

   1 //===-- MObjectFileInfo.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 using namespace llvm;
  20
  21 static bool useCompactUnwind(const Triple &T) {
  22   // Only on darwin.
  23   if (!T.isOSDarwin())
  24     return false;
  25
  26   // aarch64 always has it.
  27   if (T.getArch() == Triple::arm64 || T.getArch() == Triple::aarch64)
  28     return true;
  29
  30   // Use it on newer version of OS X.
  31   if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6))
  32     return true;
  33
  34   // And the iOS simulator.
  35   if (T.isiOS() &&
  36       (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86))
  37     return true;
  38
  39   return false;
  40 }
  41
  42 void MCObjectFileInfo::InitMachOMCObjectFileInfo(Triple T) {
  43   // MachO
  44   IsFunctionEHFrameSymbolPrivate = false;
  45   SupportsWeakOmittedEHFrame = false;
  46
  47   if (T.isOSDarwin() &&
  48       (T.getArch() == Triple::arm64 || T.getArch() == Triple::aarch64))
  49     SupportsCompactUnwindWithoutEHFrame = true;
  50
  51   PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel
  52     | dwarf::DW_EH_PE_sdata4;
  53   LSDAEncoding = FDECFIEncoding = dwarf::DW_EH_PE_pcrel;
  54   TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
  55     dwarf::DW_EH_PE_sdata4;
  56
  57   // .comm doesn't support alignment before Leopard.
  58   if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
  59     CommDirectiveSupportsAlignment = false;
  60
  61   TextSection // .text
  62     = Ctx->getMachOSection("__TEXT", "__text",
  63                            MachO::S_ATTR_PURE_INSTRUCTIONS,
  64                            SectionKind::getText());
  65   DataSection // .data
  66     = Ctx->getMachOSection("__DATA", "__data", 0,
  67                            SectionKind::getDataRel());
  68
  69   // BSSSection might not be expected initialized on msvc.
  70   BSSSection = nullptr;
  71
  72   TLSDataSection // .tdata
  73     = Ctx->getMachOSection("__DATA", "__thread_data",
  74                            MachO::S_THREAD_LOCAL_REGULAR,
  75                            SectionKind::getDataRel());
  76   TLSBSSSection // .tbss
  77     = Ctx->getMachOSection("__DATA", "__thread_bss",
  78                            MachO::S_THREAD_LOCAL_ZEROFILL,
  79                            SectionKind::getThreadBSS());
  80
  81   // TODO: Verify datarel below.
  82   TLSTLVSection // .tlv
  83     = Ctx->getMachOSection("__DATA", "__thread_vars",
  84                            MachO::S_THREAD_LOCAL_VARIABLES,
  85                            SectionKind::getDataRel());
  86
  87   TLSThreadInitSection
  88     = Ctx->getMachOSection("__DATA", "__thread_init",
  89                           MachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
  90                           SectionKind::getDataRel());
  91
  92   CStringSection // .cstring
  93     = Ctx->getMachOSection("__TEXT", "__cstring",
  94                            MachO::S_CSTRING_LITERALS,
  95                            SectionKind::getMergeable1ByteCString());
  96   UStringSection
  97     = Ctx->getMachOSection("__TEXT","__ustring", 0,
  98                            SectionKind::getMergeable2ByteCString());
  99   FourByteConstantSection // .literal4
 100     = Ctx->getMachOSection("__TEXT", "__literal4",
 101                            MachO::S_4BYTE_LITERALS,
 102                            SectionKind::getMergeableConst4());
 103   EightByteConstantSection // .literal8
 104     = Ctx->getMachOSection("__TEXT", "__literal8",
 105                            MachO::S_8BYTE_LITERALS,
 106                            SectionKind::getMergeableConst8());
 107
 108   SixteenByteConstantSection // .literal16
 109       = Ctx->getMachOSection("__TEXT", "__literal16",
 110                              MachO::S_16BYTE_LITERALS,
 111                              SectionKind::getMergeableConst16());
 112
 113   ReadOnlySection  // .const
 114     = Ctx->getMachOSection("__TEXT", "__const", 0,
 115                            SectionKind::getReadOnly());
 116
 117   TextCoalSection
 118     = Ctx->getMachOSection("__TEXT", "__textcoal_nt",
 119                            MachO::S_COALESCED |
 120                            MachO::S_ATTR_PURE_INSTRUCTIONS,
 121                            SectionKind::getText());
 122   ConstTextCoalSection
 123     = Ctx->getMachOSection("__TEXT", "__const_coal",
 124                            MachO::S_COALESCED,
 125                            SectionKind::getReadOnly());
 126   ConstDataSection  // .const_data
 127     = Ctx->getMachOSection("__DATA", "__const", 0,
 128                            SectionKind::getReadOnlyWithRel());
 129   DataCoalSection
 130     = Ctx->getMachOSection("__DATA","__datacoal_nt",
 131                            MachO::S_COALESCED,
 132                            SectionKind::getDataRel());
 133   DataCommonSection
 134     = Ctx->getMachOSection("__DATA","__common",
 135                            MachO::S_ZEROFILL,
 136                            SectionKind::getBSS());
 137   DataBSSSection
 138     = Ctx->getMachOSection("__DATA","__bss", MachO::S_ZEROFILL,
 139                            SectionKind::getBSS());
 140
 141
 142   LazySymbolPointerSection
 143     = Ctx->getMachOSection("__DATA", "__la_symbol_ptr",
 144                            MachO::S_LAZY_SYMBOL_POINTERS,
 145                            SectionKind::getMetadata());
 146   NonLazySymbolPointerSection
 147     = Ctx->getMachOSection("__DATA", "__nl_symbol_ptr",
 148                            MachO::S_NON_LAZY_SYMBOL_POINTERS,
 149                            SectionKind::getMetadata());
 150
 151   if (RelocM == Reloc::Static) {
 152     StaticCtorSection
 153       = Ctx->getMachOSection("__TEXT", "__constructor", 0,
 154                              SectionKind::getDataRel());
 155     StaticDtorSection
 156       = Ctx->getMachOSection("__TEXT", "__destructor", 0,
 157                              SectionKind::getDataRel());
 158   } else {
 159     StaticCtorSection
 160       = Ctx->getMachOSection("__DATA", "__mod_init_func",
 161                              MachO::S_MOD_INIT_FUNC_POINTERS,
 162                              SectionKind::getDataRel());
 163     StaticDtorSection
 164       = Ctx->getMachOSection("__DATA", "__mod_term_func",
 165                              MachO::S_MOD_TERM_FUNC_POINTERS,
 166                              SectionKind::getDataRel());
 167   }
 168
 169   // Exception Handling.
 170   LSDASection = Ctx->getMachOSection("__TEXT", "__gcc_except_tab", 0,
 171                                      SectionKind::getReadOnlyWithRel());
 172
 173   COFFDebugSymbolsSection = nullptr;
 174
 175   if (useCompactUnwind(T)) {
 176     CompactUnwindSection =
 177         Ctx->getMachOSection("__LD", "__compact_unwind", MachO::S_ATTR_DEBUG,
 178                              SectionKind::getReadOnly());
 179
 180     if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86)
 181       CompactUnwindDwarfEHFrameOnly = 0x04000000;
 182     else if (T.getArch() == Triple::arm64 || T.getArch() == Triple::aarch64)
 183       CompactUnwindDwarfEHFrameOnly = 0x03000000;
 184   }
 185
 186   // Debug Information.
 187   DwarfAccelNamesSection =
 188     Ctx->getMachOSection("__DWARF", "__apple_names",
 189                          MachO::S_ATTR_DEBUG,
 190                          SectionKind::getMetadata());
 191   DwarfAccelObjCSection =
 192     Ctx->getMachOSection("__DWARF", "__apple_objc",
 193                          MachO::S_ATTR_DEBUG,
 194                          SectionKind::getMetadata());
 195   // 16 character section limit...
 196   DwarfAccelNamespaceSection =
 197     Ctx->getMachOSection("__DWARF", "__apple_namespac",
 198                          MachO::S_ATTR_DEBUG,
 199                          SectionKind::getMetadata());
 200   DwarfAccelTypesSection =
 201     Ctx->getMachOSection("__DWARF", "__apple_types",
 202                          MachO::S_ATTR_DEBUG,
 203                          SectionKind::getMetadata());
 204
 205   DwarfAbbrevSection =
 206     Ctx->getMachOSection("__DWARF", "__debug_abbrev",
 207                          MachO::S_ATTR_DEBUG,
 208                          SectionKind::getMetadata());
 209   DwarfInfoSection =
 210     Ctx->getMachOSection("__DWARF", "__debug_info",
 211                          MachO::S_ATTR_DEBUG,
 212                          SectionKind::getMetadata());
 213   DwarfLineSection =
 214     Ctx->getMachOSection("__DWARF", "__debug_line",
 215                          MachO::S_ATTR_DEBUG,
 216                          SectionKind::getMetadata());
 217   DwarfFrameSection =
 218     Ctx->getMachOSection("__DWARF", "__debug_frame",
 219                          MachO::S_ATTR_DEBUG,
 220                          SectionKind::getMetadata());
 221   DwarfPubNamesSection =
 222     Ctx->getMachOSection("__DWARF", "__debug_pubnames",
 223                          MachO::S_ATTR_DEBUG,
 224                          SectionKind::getMetadata());
 225   DwarfPubTypesSection =
 226     Ctx->getMachOSection("__DWARF", "__debug_pubtypes",
 227                          MachO::S_ATTR_DEBUG,
 228                          SectionKind::getMetadata());
 229   DwarfGnuPubNamesSection =
 230     Ctx->getMachOSection("__DWARF", "__debug_gnu_pubn",
 231                          MachO::S_ATTR_DEBUG,
 232                          SectionKind::getMetadata());
 233   DwarfGnuPubTypesSection =
 234     Ctx->getMachOSection("__DWARF", "__debug_gnu_pubt",
 235                          MachO::S_ATTR_DEBUG,
 236                          SectionKind::getMetadata());
 237   DwarfStrSection =
 238     Ctx->getMachOSection("__DWARF", "__debug_str",
 239                          MachO::S_ATTR_DEBUG,
 240                          SectionKind::getMetadata());
 241   DwarfLocSection =
 242     Ctx->getMachOSection("__DWARF", "__debug_loc",
 243                          MachO::S_ATTR_DEBUG,
 244                          SectionKind::getMetadata());
 245   DwarfARangesSection =
 246     Ctx->getMachOSection("__DWARF", "__debug_aranges",
 247                          MachO::S_ATTR_DEBUG,
 248                          SectionKind::getMetadata());
 249   DwarfRangesSection =
 250     Ctx->getMachOSection("__DWARF", "__debug_ranges",
 251                          MachO::S_ATTR_DEBUG,
 252                          SectionKind::getMetadata());
 253   DwarfMacroInfoSection =
 254     Ctx->getMachOSection("__DWARF", "__debug_macinfo",
 255                          MachO::S_ATTR_DEBUG,
 256                          SectionKind::getMetadata());
 257   DwarfDebugInlineSection =
 258     Ctx->getMachOSection("__DWARF", "__debug_inlined",
 259                          MachO::S_ATTR_DEBUG,
 260                          SectionKind::getMetadata());
 261   StackMapSection =
 262     Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps", 0,
 263                          SectionKind::getMetadata());
 264
 265   TLSExtraDataSection = TLSTLVSection;
 266 }
 267
 268 void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
 269   switch (T.getArch()) {
 270   case Triple::mips:
 271   case Triple::mipsel:
 272     FDECFIEncoding = dwarf::DW_EH_PE_sdata4;
 273     break;
 274   case Triple::mips64:
 275   case Triple::mips64el:
 276     FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
 277     break;
 278   default:
 279     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 280     break;
 281   }
 282
 283   switch (T.getArch()) {
 284   case Triple::arm:
 285   case Triple::armeb:
 286   case Triple::thumb:
 287   case Triple::thumbeb:
 288     if (Ctx->getAsmInfo()->getExceptionHandlingType() == ExceptionHandling::ARM)
 289       break;
 290     // Fallthrough if not using EHABI
 291   case Triple::x86:
 292     PersonalityEncoding = (RelocM == Reloc::PIC_)
 293      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 294      : dwarf::DW_EH_PE_absptr;
 295     LSDAEncoding = (RelocM == Reloc::PIC_)
 296       ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 297       : dwarf::DW_EH_PE_absptr;
 298     TTypeEncoding = (RelocM == Reloc::PIC_)
 299      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 300      : dwarf::DW_EH_PE_absptr;
 301     break;
 302   case Triple::x86_64:
 303     if (RelocM == Reloc::PIC_) {
 304       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 305         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 306          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 307       LSDAEncoding = dwarf::DW_EH_PE_pcrel |
 308         (CMModel == CodeModel::Small
 309          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 310       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 311         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 312          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 313     } else {
 314       PersonalityEncoding =
 315         (CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 316         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 317       LSDAEncoding = (CMModel == CodeModel::Small)
 318         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 319       TTypeEncoding = (CMModel == CodeModel::Small)
 320         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 321     }
 322     break;
 323   case Triple::aarch64:
 324   case Triple::aarch64_be:
 325   case Triple::arm64:
 326   case Triple::arm64_be:
 327     // The small model guarantees static code/data size < 4GB, but not where it
 328     // will be in memory. Most of these could end up >2GB away so even a signed
 329     // pc-relative 32-bit address is insufficient, theoretically.
 330     if (RelocM == Reloc::PIC_) {
 331       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 332         dwarf::DW_EH_PE_sdata8;
 333       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
 334       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 335         dwarf::DW_EH_PE_sdata8;
 336     } else {
 337       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 338       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 339       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 340     }
 341     break;
 342   case Triple::mips:
 343   case Triple::mipsel:
 344     // MIPS uses indirect pointer to refer personality functions, so that the
 345     // eh_frame section can be read-only.  DW.ref.personality will be generated
 346     // for relocation.
 347     PersonalityEncoding = dwarf::DW_EH_PE_indirect;
 348     break;
 349   case Triple::ppc64:
 350   case Triple::ppc64le:
 351     PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 352       dwarf::DW_EH_PE_udata8;
 353     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8;
 354     TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 355       dwarf::DW_EH_PE_udata8;
 356     break;
 357   case Triple::sparc:
 358     if (RelocM == Reloc::PIC_) {
 359       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 360       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 361         dwarf::DW_EH_PE_sdata4;
 362       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 363         dwarf::DW_EH_PE_sdata4;
 364     } else {
 365       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 366       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 367       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 368     }
 369     break;
 370   case Triple::sparcv9:
 371     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 372     if (RelocM == Reloc::PIC_) {
 373       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 374         dwarf::DW_EH_PE_sdata4;
 375       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 376         dwarf::DW_EH_PE_sdata4;
 377     } else {
 378       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 379       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 380     }
 381     break;
 382   case Triple::systemz:
 383     // All currently-defined code models guarantee that 4-byte PC-relative
 384     // values will be in range.
 385     if (RelocM == Reloc::PIC_) {
 386       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 387         dwarf::DW_EH_PE_sdata4;
 388       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 389       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 390         dwarf::DW_EH_PE_sdata4;
 391     } else {
 392       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 393       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 394       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 395     }
 396     break;
 397   default:
 398     break;
 399   }
 400
 401   // Solaris requires different flags for .eh_frame to seemingly every other
 402   // platform.
 403   EHSectionType = ELF::SHT_PROGBITS;
 404   EHSectionFlags = ELF::SHF_ALLOC;
 405   if (T.getOS() == Triple::Solaris) {
 406     if (T.getArch() == Triple::x86_64)
 407       EHSectionType = ELF::SHT_X86_64_UNWIND;
 408     else
 409       EHSectionFlags |= ELF::SHF_WRITE;
 410   }
 411
 412
 413   // ELF
 414   BSSSection =
 415     Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
 416                        ELF::SHF_WRITE | ELF::SHF_ALLOC,
 417                        SectionKind::getBSS());
 418
 419   TextSection =
 420     Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
 421                        ELF::SHF_EXECINSTR |
 422                        ELF::SHF_ALLOC,
 423                        SectionKind::getText());
 424
 425   DataSection =
 426     Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
 427                        ELF::SHF_WRITE |ELF::SHF_ALLOC,
 428                        SectionKind::getDataRel());
 429
 430   ReadOnlySection =
 431     Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS,
 432                        ELF::SHF_ALLOC,
 433                        SectionKind::getReadOnly());
 434
 435   TLSDataSection =
 436     Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
 437                        ELF::SHF_ALLOC | ELF::SHF_TLS |
 438                        ELF::SHF_WRITE,
 439                        SectionKind::getThreadData());
 440
 441   TLSBSSSection =
 442     Ctx->getELFSection(".tbss", ELF::SHT_NOBITS,
 443                        ELF::SHF_ALLOC | ELF::SHF_TLS |
 444                        ELF::SHF_WRITE,
 445                        SectionKind::getThreadBSS());
 446
 447   DataRelSection =
 448     Ctx->getELFSection(".data.rel", ELF::SHT_PROGBITS,
 449                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 450                        SectionKind::getDataRel());
 451
 452   DataRelLocalSection =
 453     Ctx->getELFSection(".data.rel.local", ELF::SHT_PROGBITS,
 454                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 455                        SectionKind::getDataRelLocal());
 456
 457   DataRelROSection =
 458     Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
 459                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 460                        SectionKind::getReadOnlyWithRel());
 461
 462   DataRelROLocalSection =
 463     Ctx->getELFSection(".data.rel.ro.local", ELF::SHT_PROGBITS,
 464                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 465                        SectionKind::getReadOnlyWithRelLocal());
 466
 467   MergeableConst4Section =
 468     Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
 469                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
 470                        SectionKind::getMergeableConst4());
 471
 472   MergeableConst8Section =
 473     Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
 474                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
 475                        SectionKind::getMergeableConst8());
 476
 477   MergeableConst16Section =
 478     Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
 479                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
 480                        SectionKind::getMergeableConst16());
 481
 482   StaticCtorSection =
 483     Ctx->getELFSection(".ctors", ELF::SHT_PROGBITS,
 484                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 485                        SectionKind::getDataRel());
 486
 487   StaticDtorSection =
 488     Ctx->getELFSection(".dtors", ELF::SHT_PROGBITS,
 489                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 490                        SectionKind::getDataRel());
 491
 492   // Exception Handling Sections.
 493
 494   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
 495   // it contains relocatable pointers.  In PIC mode, this is probably a big
 496   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
 497   // adjusted or this should be a data section.
 498   LSDASection =
 499     Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
 500                        ELF::SHF_ALLOC,
 501                        SectionKind::getReadOnly());
 502
 503   COFFDebugSymbolsSection = nullptr;
 504
 505   // Debug Info Sections.
 506   DwarfAbbrevSection =
 507     Ctx->getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0,
 508                        SectionKind::getMetadata());
 509   DwarfInfoSection =
 510     Ctx->getELFSection(".debug_info", ELF::SHT_PROGBITS, 0,
 511                        SectionKind::getMetadata());
 512   DwarfLineSection =
 513     Ctx->getELFSection(".debug_line", ELF::SHT_PROGBITS, 0,
 514                        SectionKind::getMetadata());
 515   DwarfFrameSection =
 516     Ctx->getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0,
 517                        SectionKind::getMetadata());
 518   DwarfPubNamesSection =
 519     Ctx->getELFSection(".debug_pubnames", ELF::SHT_PROGBITS, 0,
 520                        SectionKind::getMetadata());
 521   DwarfPubTypesSection =
 522     Ctx->getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0,
 523                        SectionKind::getMetadata());
 524   DwarfGnuPubNamesSection =
 525     Ctx->getELFSection(".debug_gnu_pubnames", ELF::SHT_PROGBITS, 0,
 526                        SectionKind::getMetadata());
 527   DwarfGnuPubTypesSection =
 528     Ctx->getELFSection(".debug_gnu_pubtypes", ELF::SHT_PROGBITS, 0,
 529                        SectionKind::getMetadata());
 530   DwarfStrSection =
 531     Ctx->getELFSection(".debug_str", ELF::SHT_PROGBITS,
 532                        ELF::SHF_MERGE | ELF::SHF_STRINGS,
 533                        SectionKind::getMergeable1ByteCString());
 534   DwarfLocSection =
 535     Ctx->getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0,
 536                        SectionKind::getMetadata());
 537   DwarfARangesSection =
 538     Ctx->getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0,
 539                        SectionKind::getMetadata());
 540   DwarfRangesSection =
 541     Ctx->getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0,
 542                        SectionKind::getMetadata());
 543   DwarfMacroInfoSection =
 544     Ctx->getELFSection(".debug_macinfo", ELF::SHT_PROGBITS, 0,
 545                        SectionKind::getMetadata());
 546
 547   // DWARF5 Experimental Debug Info
 548
 549   // Accelerator Tables
 550   DwarfAccelNamesSection =
 551     Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0,
 552                        SectionKind::getMetadata());
 553   DwarfAccelObjCSection =
 554     Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0,
 555                        SectionKind::getMetadata());
 556   DwarfAccelNamespaceSection =
 557     Ctx->getELFSection(".apple_namespaces", ELF::SHT_PROGBITS, 0,
 558                        SectionKind::getMetadata());
 559   DwarfAccelTypesSection =
 560     Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0,
 561                        SectionKind::getMetadata());
 562
 563   // Fission Sections
 564   DwarfInfoDWOSection =
 565     Ctx->getELFSection(".debug_info.dwo", ELF::SHT_PROGBITS, 0,
 566                        SectionKind::getMetadata());
 567   DwarfAbbrevDWOSection =
 568     Ctx->getELFSection(".debug_abbrev.dwo", ELF::SHT_PROGBITS, 0,
 569                        SectionKind::getMetadata());
 570   DwarfStrDWOSection =
 571     Ctx->getELFSection(".debug_str.dwo", ELF::SHT_PROGBITS,
 572                        ELF::SHF_MERGE | ELF::SHF_STRINGS,
 573                        SectionKind::getMergeable1ByteCString());
 574   DwarfLineDWOSection =
 575     Ctx->getELFSection(".debug_line.dwo", ELF::SHT_PROGBITS, 0,
 576                        SectionKind::getMetadata());
 577   DwarfLocDWOSection =
 578     Ctx->getELFSection(".debug_loc.dwo", ELF::SHT_PROGBITS, 0,
 579                        SectionKind::getMetadata());
 580   DwarfStrOffDWOSection =
 581     Ctx->getELFSection(".debug_str_offsets.dwo", ELF::SHT_PROGBITS, 0,
 582                        SectionKind::getMetadata());
 583   DwarfAddrSection =
 584     Ctx->getELFSection(".debug_addr", ELF::SHT_PROGBITS, 0,
 585                        SectionKind::getMetadata());
 586 }
 587
 588
 589 void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
 590   bool IsWoA = T.getArch() == Triple::arm || T.getArch() == Triple::thumb;
 591
 592   // The object file format cannot represent common symbols with explicit
 593   // alignments.
 594   CommDirectiveSupportsAlignment = false;
 595
 596   // COFF
 597   BSSSection =
 598     Ctx->getCOFFSection(".bss",
 599                         COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
 600                         COFF::IMAGE_SCN_MEM_READ |
 601                         COFF::IMAGE_SCN_MEM_WRITE,
 602                         SectionKind::getBSS());
 603   TextSection =
 604     Ctx->getCOFFSection(".text",
 605                         (IsWoA ? COFF::IMAGE_SCN_MEM_16BIT
 606                                : (COFF::SectionCharacteristics)0) |
 607                         COFF::IMAGE_SCN_CNT_CODE |
 608                         COFF::IMAGE_SCN_MEM_EXECUTE |
 609                         COFF::IMAGE_SCN_MEM_READ,
 610                         SectionKind::getText());
 611   DataSection =
 612     Ctx->getCOFFSection(".data",
 613                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 614                         COFF::IMAGE_SCN_MEM_READ |
 615                         COFF::IMAGE_SCN_MEM_WRITE,
 616                         SectionKind::getDataRel());
 617   ReadOnlySection =
 618     Ctx->getCOFFSection(".rdata",
 619                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 620                         COFF::IMAGE_SCN_MEM_READ,
 621                         SectionKind::getReadOnly());
 622
 623   if (T.isKnownWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) {
 624     StaticCtorSection =
 625       Ctx->getCOFFSection(".CRT$XCU",
 626                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 627                           COFF::IMAGE_SCN_MEM_READ,
 628                           SectionKind::getReadOnly());
 629     StaticDtorSection =
 630       Ctx->getCOFFSection(".CRT$XTX",
 631                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 632                           COFF::IMAGE_SCN_MEM_READ,
 633                           SectionKind::getReadOnly());
 634   } else {
 635     StaticCtorSection =
 636       Ctx->getCOFFSection(".ctors",
 637                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 638                           COFF::IMAGE_SCN_MEM_READ |
 639                           COFF::IMAGE_SCN_MEM_WRITE,
 640                           SectionKind::getDataRel());
 641     StaticDtorSection =
 642       Ctx->getCOFFSection(".dtors",
 643                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 644                           COFF::IMAGE_SCN_MEM_READ |
 645                           COFF::IMAGE_SCN_MEM_WRITE,
 646                           SectionKind::getDataRel());
 647   }
 648
 649   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
 650   // though it contains relocatable pointers.  In PIC mode, this is probably a
 651   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
 652   // adjusted or this should be a data section.
 653   LSDASection =
 654     Ctx->getCOFFSection(".gcc_except_table",
 655                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 656                         COFF::IMAGE_SCN_MEM_READ,
 657                         SectionKind::getReadOnly());
 658
 659   // Debug info.
 660   COFFDebugSymbolsSection =
 661     Ctx->getCOFFSection(".debug$S",
 662                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 663                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 664                         COFF::IMAGE_SCN_MEM_READ,
 665                         SectionKind::getMetadata());
 666
 667   DwarfAbbrevSection =
 668     Ctx->getCOFFSection(".debug_abbrev",
 669                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 670                         COFF::IMAGE_SCN_MEM_READ,
 671                         SectionKind::getMetadata());
 672   DwarfInfoSection =
 673     Ctx->getCOFFSection(".debug_info",
 674                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 675                         COFF::IMAGE_SCN_MEM_READ,
 676                         SectionKind::getMetadata());
 677   DwarfLineSection =
 678     Ctx->getCOFFSection(".debug_line",
 679                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 680                         COFF::IMAGE_SCN_MEM_READ,
 681                         SectionKind::getMetadata());
 682   DwarfFrameSection =
 683     Ctx->getCOFFSection(".debug_frame",
 684                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 685                         COFF::IMAGE_SCN_MEM_READ,
 686                         SectionKind::getMetadata());
 687   DwarfPubNamesSection =
 688     Ctx->getCOFFSection(".debug_pubnames",
 689                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 690                         COFF::IMAGE_SCN_MEM_READ,
 691                         SectionKind::getMetadata());
 692   DwarfPubTypesSection =
 693     Ctx->getCOFFSection(".debug_pubtypes",
 694                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 695                         COFF::IMAGE_SCN_MEM_READ,
 696                         SectionKind::getMetadata());
 697   DwarfGnuPubNamesSection =
 698     Ctx->getCOFFSection(".debug_gnu_pubnames",
 699                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 700                         COFF::IMAGE_SCN_MEM_READ,
 701                         SectionKind::getMetadata());
 702   DwarfGnuPubTypesSection =
 703     Ctx->getCOFFSection(".debug_gnu_pubtypes",
 704                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 705                         COFF::IMAGE_SCN_MEM_READ,
 706                         SectionKind::getMetadata());
 707   DwarfStrSection =
 708     Ctx->getCOFFSection(".debug_str",
 709                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 710                         COFF::IMAGE_SCN_MEM_READ,
 711                         SectionKind::getMetadata());
 712   DwarfLocSection =
 713     Ctx->getCOFFSection(".debug_loc",
 714                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 715                         COFF::IMAGE_SCN_MEM_READ,
 716                         SectionKind::getMetadata());
 717   DwarfARangesSection =
 718     Ctx->getCOFFSection(".debug_aranges",
 719                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 720                         COFF::IMAGE_SCN_MEM_READ,
 721                         SectionKind::getMetadata());
 722   DwarfRangesSection =
 723     Ctx->getCOFFSection(".debug_ranges",
 724                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 725                         COFF::IMAGE_SCN_MEM_READ,
 726                         SectionKind::getMetadata());
 727   DwarfMacroInfoSection =
 728     Ctx->getCOFFSection(".debug_macinfo",
 729                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 730                         COFF::IMAGE_SCN_MEM_READ,
 731                         SectionKind::getMetadata());
 732   DwarfInfoDWOSection =
 733       Ctx->getCOFFSection(".debug_info.dwo",
 734                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 735                           COFF::IMAGE_SCN_MEM_READ,
 736                           SectionKind::getMetadata());
 737   DwarfAbbrevDWOSection =
 738       Ctx->getCOFFSection(".debug_abbrev.dwo",
 739                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 740                           COFF::IMAGE_SCN_MEM_READ,
 741                           SectionKind::getMetadata());
 742   DwarfStrDWOSection =
 743       Ctx->getCOFFSection(".debug_str.dwo",
 744                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 745                           COFF::IMAGE_SCN_MEM_READ,
 746                           SectionKind::getMetadata());
 747   DwarfLineDWOSection =
 748       Ctx->getCOFFSection(".debug_line.dwo",
 749                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 750                           COFF::IMAGE_SCN_MEM_READ,
 751                           SectionKind::getMetadata());
 752   DwarfLocDWOSection =
 753       Ctx->getCOFFSection(".debug_loc.dwo",
 754                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 755                           COFF::IMAGE_SCN_MEM_READ,
 756                           SectionKind::getMetadata());
 757   DwarfStrOffDWOSection =
 758       Ctx->getCOFFSection(".debug_str_offsets.dwo",
 759                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 760                           COFF::IMAGE_SCN_MEM_READ,
 761                           SectionKind::getMetadata());
 762
 763   DwarfAddrSection =
 764     Ctx->getCOFFSection(".debug_addr",
 765                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 766                         COFF::IMAGE_SCN_MEM_READ,
 767                         SectionKind::getMetadata());
 768
 769   DrectveSection =
 770     Ctx->getCOFFSection(".drectve",
 771                         COFF::IMAGE_SCN_LNK_INFO |
 772                         COFF::IMAGE_SCN_LNK_REMOVE,
 773                         SectionKind::getMetadata());
 774
 775   PDataSection =
 776     Ctx->getCOFFSection(".pdata",
 777                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 778                         COFF::IMAGE_SCN_MEM_READ,
 779                         SectionKind::getDataRel());
 780
 781   XDataSection =
 782     Ctx->getCOFFSection(".xdata",
 783                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 784                         COFF::IMAGE_SCN_MEM_READ,
 785                         SectionKind::getDataRel());
 786
 787   TLSDataSection =
 788     Ctx->getCOFFSection(".tls$",
 789                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 790                         COFF::IMAGE_SCN_MEM_READ |
 791                         COFF::IMAGE_SCN_MEM_WRITE,
 792                         SectionKind::getDataRel());
 793 }
 794
 795 void MCObjectFileInfo::InitMCObjectFileInfo(StringRef TT, Reloc::Model relocm,
 796                                             CodeModel::Model cm,
 797                                             MCContext &ctx) {
 798   RelocM = relocm;
 799   CMModel = cm;
 800   Ctx = &ctx;
 801
 802   // Common.
 803   CommDirectiveSupportsAlignment = true;
 804   SupportsWeakOmittedEHFrame = true;
 805   IsFunctionEHFrameSymbolPrivate = true;
 806   SupportsCompactUnwindWithoutEHFrame = false;
 807
 808   PersonalityEncoding = LSDAEncoding = FDECFIEncoding = TTypeEncoding =
 809       dwarf::DW_EH_PE_absptr;
 810
 811   CompactUnwindDwarfEHFrameOnly = 0;
 812
 813   EHFrameSection = nullptr;             // Created on demand.
 814   CompactUnwindSection = nullptr;       // Used only by selected targets.
 815   DwarfAccelNamesSection = nullptr;     // Used only by selected targets.
 816   DwarfAccelObjCSection = nullptr;      // Used only by selected targets.
 817   DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
 818   DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
 819
 820   Triple T(TT);
 821   Triple::ArchType Arch = T.getArch();
 822   // FIXME: Checking for Arch here to filter out bogus triples such as
 823   // cellspu-apple-darwin. Perhaps we should fix in Triple?
 824   if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
 825        Arch == Triple::arm || Arch == Triple::thumb ||
 826        Arch == Triple::arm64 || Arch == Triple::aarch64 ||
 827        Arch == Triple::ppc || Arch == Triple::ppc64 ||
 828        Arch == Triple::UnknownArch) &&
 829       (T.isOSDarwin() || T.isOSBinFormatMachO())) {
 830     Env = IsMachO;
 831     InitMachOMCObjectFileInfo(T);
 832   } else if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
 833               Arch == Triple::arm || Arch == Triple::thumb) &&
 834              (T.isOSWindows() && T.getObjectFormat() == Triple::COFF)) {
 835     Env = IsCOFF;
 836     InitCOFFMCObjectFileInfo(T);
 837   } else {
 838     Env = IsELF;
 839     InitELFMCObjectFileInfo(T);
 840   }
 841 }
 842
 843 const MCSection *MCObjectFileInfo::getDwarfTypesSection(uint64_t Hash) const {
 844   return Ctx->getELFSection(".debug_types", ELF::SHT_PROGBITS, ELF::SHF_GROUP,
 845                             SectionKind::getMetadata(), 0, utostr(Hash));
 846 }
 847
 848 const MCSection *
 849 MCObjectFileInfo::getDwarfTypesDWOSection(uint64_t Hash) const {
 850   return Ctx->getELFSection(".debug_types.dwo", ELF::SHT_PROGBITS,
 851                             ELF::SHF_GROUP, SectionKind::getMetadata(), 0,
 852                             utostr(Hash));
 853 }
 854
 855 void MCObjectFileInfo::InitEHFrameSection() {
 856   if (Env == IsMachO)
 857     EHFrameSection =
 858       Ctx->getMachOSection("__TEXT", "__eh_frame",
 859                            MachO::S_COALESCED |
 860                            MachO::S_ATTR_NO_TOC |
 861                            MachO::S_ATTR_STRIP_STATIC_SYMS |
 862                            MachO::S_ATTR_LIVE_SUPPORT,
 863                            SectionKind::getReadOnly());
 864   else if (Env == IsELF)
 865     EHFrameSection =
 866       Ctx->getELFSection(".eh_frame", EHSectionType,
 867                          EHSectionFlags,
 868                          SectionKind::getDataRel());
 869   else
 870     EHFrameSection =
 871       Ctx->getCOFFSection(".eh_frame",
 872                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 873                           COFF::IMAGE_SCN_MEM_READ |
 874                           COFF::IMAGE_SCN_MEM_WRITE,
 875                           SectionKind::getDataRel());
 876 }