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