lib/MC/MCObjectFileInfo.cpp

   1 //===-- MCObjectFileInfo.cpp - Object File Information --------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #include "llvm/MC/MCObjectFileInfo.h"
  11 #include "llvm/ADT/StringExtras.h"
  12 #include "llvm/ADT/Triple.h"
  13 #include "llvm/MC/MCAsmInfo.h"
  14 #include "llvm/MC/MCContext.h"
  15 #include "llvm/MC/MCSection.h"
  16 #include "llvm/MC/MCSectionCOFF.h"
  17 #include "llvm/MC/MCSectionELF.h"
  18 #include "llvm/MC/MCSectionMachO.h"
  19 #include "llvm/Support/COFF.h"
  20
  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   DwarfTUIndexSection =
 266       Ctx->getMachOSection("__DWARF", "__debug_tu_index", MachO::S_ATTR_DEBUG,
 267                            SectionKind::getMetadata());
 268   StackMapSection = Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps",
 269                                          0, SectionKind::getMetadata());
 270
 271   FaultMapSection = Ctx->getMachOSection("__LLVM_FAULTMAPS", "__llvm_faultmaps",
 272                                          0, SectionKind::getMetadata());
 273
 274   TLSExtraDataSection = TLSTLVSection;
 275 }
 276
 277 void MCObjectFileInfo::initELFMCObjectFileInfo(Triple T) {
 278   switch (T.getArch()) {
 279   case Triple::mips:
 280   case Triple::mipsel:
 281     FDECFIEncoding = dwarf::DW_EH_PE_sdata4;
 282     break;
 283   case Triple::mips64:
 284   case Triple::mips64el:
 285     FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
 286     break;
 287   case Triple::x86_64:
 288     FDECFIEncoding = dwarf::DW_EH_PE_pcrel |
 289                      ((CMModel == CodeModel::Large) ? dwarf::DW_EH_PE_sdata8
 290                                                     : dwarf::DW_EH_PE_sdata4);
 291     break;
 292   default:
 293     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 294     break;
 295   }
 296
 297   switch (T.getArch()) {
 298   case Triple::arm:
 299   case Triple::armeb:
 300   case Triple::thumb:
 301   case Triple::thumbeb:
 302     if (Ctx->getAsmInfo()->getExceptionHandlingType() == ExceptionHandling::ARM)
 303       break;
 304     // Fallthrough if not using EHABI
 305   case Triple::ppc:
 306   case Triple::x86:
 307     PersonalityEncoding = (RelocM == Reloc::PIC_)
 308      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 309      : dwarf::DW_EH_PE_absptr;
 310     LSDAEncoding = (RelocM == Reloc::PIC_)
 311       ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 312       : dwarf::DW_EH_PE_absptr;
 313     TTypeEncoding = (RelocM == Reloc::PIC_)
 314      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 315      : dwarf::DW_EH_PE_absptr;
 316     break;
 317   case Triple::x86_64:
 318     if (RelocM == Reloc::PIC_) {
 319       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 320         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 321          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 322       LSDAEncoding = dwarf::DW_EH_PE_pcrel |
 323         (CMModel == CodeModel::Small
 324          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 325       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 326         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 327          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 328     } else {
 329       PersonalityEncoding =
 330         (CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 331         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 332       LSDAEncoding = (CMModel == CodeModel::Small)
 333         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 334       TTypeEncoding = (CMModel == CodeModel::Small)
 335         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 336     }
 337     break;
 338   case Triple::aarch64:
 339   case Triple::aarch64_be:
 340     // The small model guarantees static code/data size < 4GB, but not where it
 341     // will be in memory. Most of these could end up >2GB away so even a signed
 342     // pc-relative 32-bit address is insufficient, theoretically.
 343     if (RelocM == Reloc::PIC_) {
 344       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 345         dwarf::DW_EH_PE_sdata8;
 346       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
 347       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 348         dwarf::DW_EH_PE_sdata8;
 349     } else {
 350       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 351       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 352       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 353     }
 354     break;
 355   case Triple::mips:
 356   case Triple::mipsel:
 357   case Triple::mips64:
 358   case Triple::mips64el:
 359     // MIPS uses indirect pointer to refer personality functions and types, so
 360     // that the eh_frame section can be read-only. DW.ref.personality will be
 361     // generated for relocation.
 362     PersonalityEncoding = dwarf::DW_EH_PE_indirect;
 363     // FIXME: The N64 ABI probably ought to use DW_EH_PE_sdata8 but we can't
 364     //        identify N64 from just a triple.
 365     TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 366                     dwarf::DW_EH_PE_sdata4;
 367     // We don't support PC-relative LSDA references in GAS so we use the default
 368     // DW_EH_PE_absptr for those.
 369     break;
 370   case Triple::ppc64:
 371   case Triple::ppc64le:
 372     PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 373       dwarf::DW_EH_PE_udata8;
 374     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8;
 375     TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 376       dwarf::DW_EH_PE_udata8;
 377     break;
 378   case Triple::sparcel:
 379   case Triple::sparc:
 380     if (RelocM == Reloc::PIC_) {
 381       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 382       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 383         dwarf::DW_EH_PE_sdata4;
 384       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 385         dwarf::DW_EH_PE_sdata4;
 386     } else {
 387       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 388       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 389       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 390     }
 391     break;
 392   case Triple::sparcv9:
 393     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 394     if (RelocM == Reloc::PIC_) {
 395       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 396         dwarf::DW_EH_PE_sdata4;
 397       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 398         dwarf::DW_EH_PE_sdata4;
 399     } else {
 400       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 401       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 402     }
 403     break;
 404   case Triple::systemz:
 405     // All currently-defined code models guarantee that 4-byte PC-relative
 406     // values will be in range.
 407     if (RelocM == Reloc::PIC_) {
 408       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 409         dwarf::DW_EH_PE_sdata4;
 410       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 411       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 412         dwarf::DW_EH_PE_sdata4;
 413     } else {
 414       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 415       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 416       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 417     }
 418     break;
 419   default:
 420     break;
 421   }
 422
 423   unsigned EHSectionType = T.getArch() == Triple::x86_64
 424                                ? ELF::SHT_X86_64_UNWIND
 425                                : ELF::SHT_PROGBITS;
 426
 427   // Solaris requires different flags for .eh_frame to seemingly every other
 428   // platform.
 429   unsigned EHSectionFlags = ELF::SHF_ALLOC;
 430   if (T.isOSSolaris() && T.getArch() != Triple::x86_64)
 431     EHSectionFlags |= ELF::SHF_WRITE;
 432
 433   // ELF
 434   BSSSection = Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
 435                                   ELF::SHF_WRITE | ELF::SHF_ALLOC);
 436
 437   TextSection = Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
 438                                    ELF::SHF_EXECINSTR | ELF::SHF_ALLOC);
 439
 440   DataSection = Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
 441                                    ELF::SHF_WRITE | ELF::SHF_ALLOC);
 442
 443   ReadOnlySection =
 444       Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
 445
 446   TLSDataSection =
 447       Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
 448                          ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
 449
 450   TLSBSSSection = Ctx->getELFSection(
 451       ".tbss", ELF::SHT_NOBITS, ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
 452
 453   DataRelROSection = Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
 454                                         ELF::SHF_ALLOC | ELF::SHF_WRITE);
 455
 456   MergeableConst4Section =
 457       Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
 458                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 4, "");
 459
 460   MergeableConst8Section =
 461       Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
 462                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 8, "");
 463
 464   MergeableConst16Section =
 465       Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
 466                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 16, "");
 467
 468   StaticCtorSection = Ctx->getELFSection(".ctors", ELF::SHT_PROGBITS,
 469                                          ELF::SHF_ALLOC | ELF::SHF_WRITE);
 470
 471   StaticDtorSection = Ctx->getELFSection(".dtors", ELF::SHT_PROGBITS,
 472                                          ELF::SHF_ALLOC | ELF::SHF_WRITE);
 473
 474   // Exception Handling Sections.
 475
 476   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
 477   // it contains relocatable pointers.  In PIC mode, this is probably a big
 478   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
 479   // adjusted or this should be a data section.
 480   LSDASection = Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
 481                                    ELF::SHF_ALLOC);
 482
 483   COFFDebugSymbolsSection = nullptr;
 484
 485   // Debug Info Sections.
 486   DwarfAbbrevSection = Ctx->getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0,
 487                                           "section_abbrev");
 488   DwarfInfoSection =
 489       Ctx->getELFSection(".debug_info", ELF::SHT_PROGBITS, 0, "section_info");
 490   DwarfLineSection = Ctx->getELFSection(".debug_line", ELF::SHT_PROGBITS, 0);
 491   DwarfFrameSection = Ctx->getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0);
 492   DwarfPubNamesSection =
 493       Ctx->getELFSection(".debug_pubnames", ELF::SHT_PROGBITS, 0);
 494   DwarfPubTypesSection =
 495       Ctx->getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0);
 496   DwarfGnuPubNamesSection =
 497       Ctx->getELFSection(".debug_gnu_pubnames", ELF::SHT_PROGBITS, 0);
 498   DwarfGnuPubTypesSection =
 499       Ctx->getELFSection(".debug_gnu_pubtypes", ELF::SHT_PROGBITS, 0);
 500   DwarfStrSection =
 501       Ctx->getELFSection(".debug_str", ELF::SHT_PROGBITS,
 502                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
 503   DwarfLocSection = Ctx->getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0);
 504   DwarfARangesSection =
 505       Ctx->getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0);
 506   DwarfRangesSection =
 507       Ctx->getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0, "debug_range");
 508
 509   // DWARF5 Experimental Debug Info
 510
 511   // Accelerator Tables
 512   DwarfAccelNamesSection =
 513       Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0, "names_begin");
 514   DwarfAccelObjCSection =
 515       Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0, "objc_begin");
 516   DwarfAccelNamespaceSection = Ctx->getELFSection(
 517       ".apple_namespaces", ELF::SHT_PROGBITS, 0, "namespac_begin");
 518   DwarfAccelTypesSection =
 519       Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0, "types_begin");
 520
 521   // Fission Sections
 522   DwarfInfoDWOSection =
 523       Ctx->getELFSection(".debug_info.dwo", ELF::SHT_PROGBITS, 0);
 524   DwarfTypesDWOSection =
 525       Ctx->getELFSection(".debug_types.dwo", ELF::SHT_PROGBITS, 0);
 526   DwarfAbbrevDWOSection =
 527       Ctx->getELFSection(".debug_abbrev.dwo", ELF::SHT_PROGBITS, 0);
 528   DwarfStrDWOSection =
 529       Ctx->getELFSection(".debug_str.dwo", ELF::SHT_PROGBITS,
 530                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
 531   DwarfLineDWOSection =
 532       Ctx->getELFSection(".debug_line.dwo", ELF::SHT_PROGBITS, 0);
 533   DwarfLocDWOSection =
 534       Ctx->getELFSection(".debug_loc.dwo", ELF::SHT_PROGBITS, 0, "skel_loc");
 535   DwarfStrOffDWOSection =
 536       Ctx->getELFSection(".debug_str_offsets.dwo", ELF::SHT_PROGBITS, 0);
 537   DwarfAddrSection =
 538       Ctx->getELFSection(".debug_addr", ELF::SHT_PROGBITS, 0, "addr_sec");
 539
 540   // DWP Sections
 541   DwarfCUIndexSection =
 542       Ctx->getELFSection(".debug_cu_index", ELF::SHT_PROGBITS, 0);
 543   DwarfTUIndexSection =
 544       Ctx->getELFSection(".debug_tu_index", ELF::SHT_PROGBITS, 0);
 545
 546   StackMapSection =
 547       Ctx->getELFSection(".llvm_stackmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
 548
 549   FaultMapSection =
 550       Ctx->getELFSection(".llvm_faultmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
 551
 552   EHFrameSection =
 553       Ctx->getELFSection(".eh_frame", EHSectionType, EHSectionFlags);
 554 }
 555
 556 void MCObjectFileInfo::initCOFFMCObjectFileInfo(Triple T) {
 557   EHFrameSection = Ctx->getCOFFSection(
 558       ".eh_frame", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 559                        COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
 560       SectionKind::getData());
 561
 562   bool IsWoA = T.getArch() == Triple::arm || T.getArch() == Triple::thumb;
 563
 564   CommDirectiveSupportsAlignment = true;
 565
 566   // COFF
 567   BSSSection = Ctx->getCOFFSection(
 568       ".bss", COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
 569                   COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
 570       SectionKind::getBSS());
 571   TextSection = Ctx->getCOFFSection(
 572       ".text",
 573       (IsWoA ? COFF::IMAGE_SCN_MEM_16BIT : (COFF::SectionCharacteristics)0) |
 574           COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE |
 575           COFF::IMAGE_SCN_MEM_READ,
 576       SectionKind::getText());
 577   DataSection = Ctx->getCOFFSection(
 578       ".data", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
 579                    COFF::IMAGE_SCN_MEM_WRITE,
 580       SectionKind::getData());
 581   ReadOnlySection = Ctx->getCOFFSection(
 582       ".rdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
 583       SectionKind::getReadOnly());
 584
 585   if (T.isKnownWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) {
 586     StaticCtorSection =
 587         Ctx->getCOFFSection(".CRT$XCU", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 588                                             COFF::IMAGE_SCN_MEM_READ,
 589                             SectionKind::getReadOnly());
 590     StaticDtorSection =
 591         Ctx->getCOFFSection(".CRT$XTX", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 592                                             COFF::IMAGE_SCN_MEM_READ,
 593                             SectionKind::getReadOnly());
 594   } else {
 595     StaticCtorSection = Ctx->getCOFFSection(
 596         ".ctors", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 597                       COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
 598         SectionKind::getData());
 599     StaticDtorSection = Ctx->getCOFFSection(
 600         ".dtors", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 601                       COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
 602         SectionKind::getData());
 603   }
 604
 605   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
 606   // though it contains relocatable pointers.  In PIC mode, this is probably a
 607   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
 608   // adjusted or this should be a data section.
 609   if (T.getArch() == Triple::x86_64) {
 610     // On Windows 64 with SEH, the LSDA is emitted into the .xdata section
 611     LSDASection = nullptr;
 612   } else {
 613     LSDASection = Ctx->getCOFFSection(".gcc_except_table",
 614                                       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 615                                           COFF::IMAGE_SCN_MEM_READ,
 616                                       SectionKind::getReadOnly());
 617   }
 618
 619   // Debug info.
 620   COFFDebugSymbolsSection =
 621       Ctx->getCOFFSection(".debug$S", COFF::IMAGE_SCN_MEM_DISCARDABLE |
 622                                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 623                                           COFF::IMAGE_SCN_MEM_READ,
 624                           SectionKind::getMetadata());
 625
 626   DwarfAbbrevSection = Ctx->getCOFFSection(
 627       ".debug_abbrev",
 628       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 629           COFF::IMAGE_SCN_MEM_READ,
 630       SectionKind::getMetadata(), "section_abbrev");
 631   DwarfInfoSection = Ctx->getCOFFSection(
 632       ".debug_info",
 633       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 634           COFF::IMAGE_SCN_MEM_READ,
 635       SectionKind::getMetadata(), "section_info");
 636   DwarfLineSection = Ctx->getCOFFSection(
 637       ".debug_line",
 638       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 639           COFF::IMAGE_SCN_MEM_READ,
 640       SectionKind::getMetadata(), "section_line");
 641
 642   DwarfFrameSection = Ctx->getCOFFSection(
 643       ".debug_frame",
 644       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 645           COFF::IMAGE_SCN_MEM_READ,
 646       SectionKind::getMetadata());
 647   DwarfPubNamesSection = Ctx->getCOFFSection(
 648       ".debug_pubnames",
 649       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 650           COFF::IMAGE_SCN_MEM_READ,
 651       SectionKind::getMetadata());
 652   DwarfPubTypesSection = Ctx->getCOFFSection(
 653       ".debug_pubtypes",
 654       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 655           COFF::IMAGE_SCN_MEM_READ,
 656       SectionKind::getMetadata());
 657   DwarfGnuPubNamesSection = Ctx->getCOFFSection(
 658       ".debug_gnu_pubnames",
 659       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 660           COFF::IMAGE_SCN_MEM_READ,
 661       SectionKind::getMetadata());
 662   DwarfGnuPubTypesSection = Ctx->getCOFFSection(
 663       ".debug_gnu_pubtypes",
 664       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 665           COFF::IMAGE_SCN_MEM_READ,
 666       SectionKind::getMetadata());
 667   DwarfStrSection = Ctx->getCOFFSection(
 668       ".debug_str",
 669       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 670           COFF::IMAGE_SCN_MEM_READ,
 671       SectionKind::getMetadata(), "info_string");
 672   DwarfLocSection = Ctx->getCOFFSection(
 673       ".debug_loc",
 674       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 675           COFF::IMAGE_SCN_MEM_READ,
 676       SectionKind::getMetadata(), "section_debug_loc");
 677   DwarfARangesSection = Ctx->getCOFFSection(
 678       ".debug_aranges",
 679       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 680           COFF::IMAGE_SCN_MEM_READ,
 681       SectionKind::getMetadata());
 682   DwarfRangesSection = Ctx->getCOFFSection(
 683       ".debug_ranges",
 684       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 685           COFF::IMAGE_SCN_MEM_READ,
 686       SectionKind::getMetadata(), "debug_range");
 687   DwarfInfoDWOSection = Ctx->getCOFFSection(
 688       ".debug_info.dwo",
 689       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 690           COFF::IMAGE_SCN_MEM_READ,
 691       SectionKind::getMetadata(), "section_info_dwo");
 692   DwarfTypesDWOSection = Ctx->getCOFFSection(
 693       ".debug_types.dwo",
 694       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 695           COFF::IMAGE_SCN_MEM_READ,
 696       SectionKind::getMetadata(), "section_types_dwo");
 697   DwarfAbbrevDWOSection = Ctx->getCOFFSection(
 698       ".debug_abbrev.dwo",
 699       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 700           COFF::IMAGE_SCN_MEM_READ,
 701       SectionKind::getMetadata(), "section_abbrev_dwo");
 702   DwarfStrDWOSection = Ctx->getCOFFSection(
 703       ".debug_str.dwo",
 704       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 705           COFF::IMAGE_SCN_MEM_READ,
 706       SectionKind::getMetadata(), "skel_string");
 707   DwarfLineDWOSection = Ctx->getCOFFSection(
 708       ".debug_line.dwo",
 709       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 710           COFF::IMAGE_SCN_MEM_READ,
 711       SectionKind::getMetadata());
 712   DwarfLocDWOSection = Ctx->getCOFFSection(
 713       ".debug_loc.dwo",
 714       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 715           COFF::IMAGE_SCN_MEM_READ,
 716       SectionKind::getMetadata(), "skel_loc");
 717   DwarfStrOffDWOSection = Ctx->getCOFFSection(
 718       ".debug_str_offsets.dwo",
 719       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 720           COFF::IMAGE_SCN_MEM_READ,
 721       SectionKind::getMetadata());
 722   DwarfAddrSection = Ctx->getCOFFSection(
 723       ".debug_addr",
 724       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 725           COFF::IMAGE_SCN_MEM_READ,
 726       SectionKind::getMetadata(), "addr_sec");
 727   DwarfCUIndexSection = Ctx->getCOFFSection(
 728       ".debug_cu_index",
 729       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 730           COFF::IMAGE_SCN_MEM_READ,
 731       SectionKind::getMetadata());
 732   DwarfTUIndexSection = Ctx->getCOFFSection(
 733       ".debug_tu_index",
 734       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 735           COFF::IMAGE_SCN_MEM_READ,
 736       SectionKind::getMetadata());
 737   DwarfAccelNamesSection = Ctx->getCOFFSection(
 738       ".apple_names",
 739       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 740           COFF::IMAGE_SCN_MEM_READ,
 741       SectionKind::getMetadata(), "names_begin");
 742   DwarfAccelNamespaceSection = Ctx->getCOFFSection(
 743       ".apple_namespaces",
 744       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 745           COFF::IMAGE_SCN_MEM_READ,
 746       SectionKind::getMetadata(), "namespac_begin");
 747   DwarfAccelTypesSection = Ctx->getCOFFSection(
 748       ".apple_types",
 749       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 750           COFF::IMAGE_SCN_MEM_READ,
 751       SectionKind::getMetadata(), "types_begin");
 752   DwarfAccelObjCSection = Ctx->getCOFFSection(
 753       ".apple_objc",
 754       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 755           COFF::IMAGE_SCN_MEM_READ,
 756       SectionKind::getMetadata(), "objc_begin");
 757
 758   DrectveSection = Ctx->getCOFFSection(
 759       ".drectve", COFF::IMAGE_SCN_LNK_INFO | COFF::IMAGE_SCN_LNK_REMOVE,
 760       SectionKind::getMetadata());
 761
 762   PDataSection = Ctx->getCOFFSection(
 763       ".pdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
 764       SectionKind::getData());
 765
 766   XDataSection = Ctx->getCOFFSection(
 767       ".xdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
 768       SectionKind::getData());
 769
 770   SXDataSection = Ctx->getCOFFSection(".sxdata", COFF::IMAGE_SCN_LNK_INFO,
 771                                       SectionKind::getMetadata());
 772
 773   TLSDataSection = Ctx->getCOFFSection(
 774       ".tls$", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
 775                    COFF::IMAGE_SCN_MEM_WRITE,
 776       SectionKind::getData());
 777
 778   StackMapSection = Ctx->getCOFFSection(".llvm_stackmaps",
 779                                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 780                                             COFF::IMAGE_SCN_MEM_READ,
 781                                         SectionKind::getReadOnly());
 782 }
 783
 784 void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple,
 785                                             Reloc::Model relocm,
 786                                             CodeModel::Model cm,
 787                                             MCContext &ctx) {
 788   RelocM = relocm;
 789   CMModel = cm;
 790   Ctx = &ctx;
 791
 792   // Common.
 793   CommDirectiveSupportsAlignment = true;
 794   SupportsWeakOmittedEHFrame = true;
 795   SupportsCompactUnwindWithoutEHFrame = false;
 796   OmitDwarfIfHaveCompactUnwind = false;
 797
 798   PersonalityEncoding = LSDAEncoding = FDECFIEncoding = TTypeEncoding =
 799       dwarf::DW_EH_PE_absptr;
 800
 801   CompactUnwindDwarfEHFrameOnly = 0;
 802
 803   EHFrameSection = nullptr;             // Created on demand.
 804   CompactUnwindSection = nullptr;       // Used only by selected targets.
 805   DwarfAccelNamesSection = nullptr;     // Used only by selected targets.
 806   DwarfAccelObjCSection = nullptr;      // Used only by selected targets.
 807   DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
 808   DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
 809
 810   TT = TheTriple;
 811
 812   switch (TT.getObjectFormat()) {
 813   case Triple::MachO:
 814     Env = IsMachO;
 815     initMachOMCObjectFileInfo(TT);
 816     break;
 817   case Triple::COFF:
 818     if (!TT.isOSWindows())
 819       report_fatal_error(
 820           "Cannot initialize MC for non-Windows COFF object files.");
 821
 822     Env = IsCOFF;
 823     initCOFFMCObjectFileInfo(TT);
 824     break;
 825   case Triple::ELF:
 826     Env = IsELF;
 827     initELFMCObjectFileInfo(TT);
 828     break;
 829   case Triple::UnknownObjectFormat:
 830     report_fatal_error("Cannot initialize MC for unknown object file format.");
 831     break;
 832   }
 833 }
 834
 835 void MCObjectFileInfo::InitMCObjectFileInfo(StringRef TT, Reloc::Model RM,
 836                                             CodeModel::Model CM,
 837                                             MCContext &ctx) {
 838   InitMCObjectFileInfo(Triple(TT), RM, CM, ctx);
 839 }
 840
 841 MCSection *MCObjectFileInfo::getDwarfTypesSection(uint64_t Hash) const {
 842   return Ctx->getELFSection(".debug_types", ELF::SHT_PROGBITS, ELF::SHF_GROUP,
 843                             0, utostr(Hash));
 844 }