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