contrib/llvm/lib/MC/MCObjectFileInfo.cpp

   1 //===-- MObjectFileInfo.cpp - Object File Information ---------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #include "llvm/MC/MCObjectFileInfo.h"
  11 #include "llvm/ADT/StringExtras.h"
  12 #include "llvm/ADT/Triple.h"
  13 #include "llvm/MC/MCAsmInfo.h"
  14 #include "llvm/MC/MCContext.h"
  15 #include "llvm/MC/MCSection.h"
  16 #include "llvm/MC/MCSectionCOFF.h"
  17 #include "llvm/MC/MCSectionELF.h"
  18 #include "llvm/MC/MCSectionMachO.h"
  19 using namespace llvm;
  20
  21 static bool useCompactUnwind(const Triple &T) {
  22   // Only on darwin.
  23   if (!T.isOSDarwin())
  24     return false;
  25
  26   // aarch64 always has it.
  27   if (T.getArch() == Triple::arm64 || T.getArch() == Triple::aarch64)
  28     return true;
  29
  30   // Use it on newer version of OS X.
  31   if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6))
  32     return true;
  33
  34   // And the iOS simulator.
  35   if (T.isiOS() &&
  36       (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86))
  37     return true;
  38
  39   return false;
  40 }
  41
  42 void MCObjectFileInfo::InitMachOMCObjectFileInfo(Triple T) {
  43   // MachO
  44   SupportsWeakOmittedEHFrame = false;
  45
  46   if (T.isOSDarwin() &&
  47       (T.getArch() == Triple::arm64 || T.getArch() == Triple::aarch64))
  48     SupportsCompactUnwindWithoutEHFrame = true;
  49
  50   PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel
  51     | dwarf::DW_EH_PE_sdata4;
  52   LSDAEncoding = FDECFIEncoding = dwarf::DW_EH_PE_pcrel;
  53   TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
  54     dwarf::DW_EH_PE_sdata4;
  55
  56   // .comm doesn't support alignment before Leopard.
  57   if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
  58     CommDirectiveSupportsAlignment = false;
  59
  60   TextSection // .text
  61     = Ctx->getMachOSection("__TEXT", "__text",
  62                            MachO::S_ATTR_PURE_INSTRUCTIONS,
  63                            SectionKind::getText());
  64   DataSection // .data
  65     = Ctx->getMachOSection("__DATA", "__data", 0,
  66                            SectionKind::getDataRel());
  67
  68   // BSSSection might not be expected initialized on msvc.
  69   BSSSection = nullptr;
  70
  71   TLSDataSection // .tdata
  72     = Ctx->getMachOSection("__DATA", "__thread_data",
  73                            MachO::S_THREAD_LOCAL_REGULAR,
  74                            SectionKind::getDataRel());
  75   TLSBSSSection // .tbss
  76     = Ctx->getMachOSection("__DATA", "__thread_bss",
  77                            MachO::S_THREAD_LOCAL_ZEROFILL,
  78                            SectionKind::getThreadBSS());
  79
  80   // TODO: Verify datarel below.
  81   TLSTLVSection // .tlv
  82     = Ctx->getMachOSection("__DATA", "__thread_vars",
  83                            MachO::S_THREAD_LOCAL_VARIABLES,
  84                            SectionKind::getDataRel());
  85
  86   TLSThreadInitSection
  87     = Ctx->getMachOSection("__DATA", "__thread_init",
  88                           MachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
  89                           SectionKind::getDataRel());
  90
  91   CStringSection // .cstring
  92     = Ctx->getMachOSection("__TEXT", "__cstring",
  93                            MachO::S_CSTRING_LITERALS,
  94                            SectionKind::getMergeable1ByteCString());
  95   UStringSection
  96     = Ctx->getMachOSection("__TEXT","__ustring", 0,
  97                            SectionKind::getMergeable2ByteCString());
  98   FourByteConstantSection // .literal4
  99     = Ctx->getMachOSection("__TEXT", "__literal4",
 100                            MachO::S_4BYTE_LITERALS,
 101                            SectionKind::getMergeableConst4());
 102   EightByteConstantSection // .literal8
 103     = Ctx->getMachOSection("__TEXT", "__literal8",
 104                            MachO::S_8BYTE_LITERALS,
 105                            SectionKind::getMergeableConst8());
 106
 107   SixteenByteConstantSection // .literal16
 108       = Ctx->getMachOSection("__TEXT", "__literal16",
 109                              MachO::S_16BYTE_LITERALS,
 110                              SectionKind::getMergeableConst16());
 111
 112   ReadOnlySection  // .const
 113     = Ctx->getMachOSection("__TEXT", "__const", 0,
 114                            SectionKind::getReadOnly());
 115
 116   TextCoalSection
 117     = Ctx->getMachOSection("__TEXT", "__textcoal_nt",
 118                            MachO::S_COALESCED |
 119                            MachO::S_ATTR_PURE_INSTRUCTIONS,
 120                            SectionKind::getText());
 121   ConstTextCoalSection
 122     = Ctx->getMachOSection("__TEXT", "__const_coal",
 123                            MachO::S_COALESCED,
 124                            SectionKind::getReadOnly());
 125   ConstDataSection  // .const_data
 126     = Ctx->getMachOSection("__DATA", "__const", 0,
 127                            SectionKind::getReadOnlyWithRel());
 128   DataCoalSection
 129     = Ctx->getMachOSection("__DATA","__datacoal_nt",
 130                            MachO::S_COALESCED,
 131                            SectionKind::getDataRel());
 132   DataCommonSection
 133     = Ctx->getMachOSection("__DATA","__common",
 134                            MachO::S_ZEROFILL,
 135                            SectionKind::getBSS());
 136   DataBSSSection
 137     = Ctx->getMachOSection("__DATA","__bss", MachO::S_ZEROFILL,
 138                            SectionKind::getBSS());
 139
 140
 141   LazySymbolPointerSection
 142     = Ctx->getMachOSection("__DATA", "__la_symbol_ptr",
 143                            MachO::S_LAZY_SYMBOL_POINTERS,
 144                            SectionKind::getMetadata());
 145   NonLazySymbolPointerSection
 146     = Ctx->getMachOSection("__DATA", "__nl_symbol_ptr",
 147                            MachO::S_NON_LAZY_SYMBOL_POINTERS,
 148                            SectionKind::getMetadata());
 149
 150   if (RelocM == Reloc::Static) {
 151     StaticCtorSection
 152       = Ctx->getMachOSection("__TEXT", "__constructor", 0,
 153                              SectionKind::getDataRel());
 154     StaticDtorSection
 155       = Ctx->getMachOSection("__TEXT", "__destructor", 0,
 156                              SectionKind::getDataRel());
 157   } else {
 158     StaticCtorSection
 159       = Ctx->getMachOSection("__DATA", "__mod_init_func",
 160                              MachO::S_MOD_INIT_FUNC_POINTERS,
 161                              SectionKind::getDataRel());
 162     StaticDtorSection
 163       = Ctx->getMachOSection("__DATA", "__mod_term_func",
 164                              MachO::S_MOD_TERM_FUNC_POINTERS,
 165                              SectionKind::getDataRel());
 166   }
 167
 168   // Exception Handling.
 169   LSDASection = Ctx->getMachOSection("__TEXT", "__gcc_except_tab", 0,
 170                                      SectionKind::getReadOnlyWithRel());
 171
 172   COFFDebugSymbolsSection = nullptr;
 173
 174   if (useCompactUnwind(T)) {
 175     CompactUnwindSection =
 176         Ctx->getMachOSection("__LD", "__compact_unwind", MachO::S_ATTR_DEBUG,
 177                              SectionKind::getReadOnly());
 178
 179     if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86)
 180       CompactUnwindDwarfEHFrameOnly = 0x04000000;
 181     else if (T.getArch() == Triple::arm64 || T.getArch() == Triple::aarch64)
 182       CompactUnwindDwarfEHFrameOnly = 0x03000000;
 183   }
 184
 185   // Debug Information.
 186   DwarfAccelNamesSection =
 187     Ctx->getMachOSection("__DWARF", "__apple_names",
 188                          MachO::S_ATTR_DEBUG,
 189                          SectionKind::getMetadata());
 190   DwarfAccelObjCSection =
 191     Ctx->getMachOSection("__DWARF", "__apple_objc",
 192                          MachO::S_ATTR_DEBUG,
 193                          SectionKind::getMetadata());
 194   // 16 character section limit...
 195   DwarfAccelNamespaceSection =
 196     Ctx->getMachOSection("__DWARF", "__apple_namespac",
 197                          MachO::S_ATTR_DEBUG,
 198                          SectionKind::getMetadata());
 199   DwarfAccelTypesSection =
 200     Ctx->getMachOSection("__DWARF", "__apple_types",
 201                          MachO::S_ATTR_DEBUG,
 202                          SectionKind::getMetadata());
 203
 204   DwarfAbbrevSection =
 205     Ctx->getMachOSection("__DWARF", "__debug_abbrev",
 206                          MachO::S_ATTR_DEBUG,
 207                          SectionKind::getMetadata());
 208   DwarfInfoSection =
 209     Ctx->getMachOSection("__DWARF", "__debug_info",
 210                          MachO::S_ATTR_DEBUG,
 211                          SectionKind::getMetadata());
 212   DwarfLineSection =
 213     Ctx->getMachOSection("__DWARF", "__debug_line",
 214                          MachO::S_ATTR_DEBUG,
 215                          SectionKind::getMetadata());
 216   DwarfFrameSection =
 217     Ctx->getMachOSection("__DWARF", "__debug_frame",
 218                          MachO::S_ATTR_DEBUG,
 219                          SectionKind::getMetadata());
 220   DwarfPubNamesSection =
 221     Ctx->getMachOSection("__DWARF", "__debug_pubnames",
 222                          MachO::S_ATTR_DEBUG,
 223                          SectionKind::getMetadata());
 224   DwarfPubTypesSection =
 225     Ctx->getMachOSection("__DWARF", "__debug_pubtypes",
 226                          MachO::S_ATTR_DEBUG,
 227                          SectionKind::getMetadata());
 228   DwarfGnuPubNamesSection =
 229     Ctx->getMachOSection("__DWARF", "__debug_gnu_pubn",
 230                          MachO::S_ATTR_DEBUG,
 231                          SectionKind::getMetadata());
 232   DwarfGnuPubTypesSection =
 233     Ctx->getMachOSection("__DWARF", "__debug_gnu_pubt",
 234                          MachO::S_ATTR_DEBUG,
 235                          SectionKind::getMetadata());
 236   DwarfStrSection =
 237     Ctx->getMachOSection("__DWARF", "__debug_str",
 238                          MachO::S_ATTR_DEBUG,
 239                          SectionKind::getMetadata());
 240   DwarfLocSection =
 241     Ctx->getMachOSection("__DWARF", "__debug_loc",
 242                          MachO::S_ATTR_DEBUG,
 243                          SectionKind::getMetadata());
 244   DwarfARangesSection =
 245     Ctx->getMachOSection("__DWARF", "__debug_aranges",
 246                          MachO::S_ATTR_DEBUG,
 247                          SectionKind::getMetadata());
 248   DwarfRangesSection =
 249     Ctx->getMachOSection("__DWARF", "__debug_ranges",
 250                          MachO::S_ATTR_DEBUG,
 251                          SectionKind::getMetadata());
 252   DwarfMacroInfoSection =
 253     Ctx->getMachOSection("__DWARF", "__debug_macinfo",
 254                          MachO::S_ATTR_DEBUG,
 255                          SectionKind::getMetadata());
 256   DwarfDebugInlineSection =
 257     Ctx->getMachOSection("__DWARF", "__debug_inlined",
 258                          MachO::S_ATTR_DEBUG,
 259                          SectionKind::getMetadata());
 260   StackMapSection =
 261     Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps", 0,
 262                          SectionKind::getMetadata());
 263
 264   TLSExtraDataSection = TLSTLVSection;
 265 }
 266
 267 void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
 268   switch (T.getArch()) {
 269   case Triple::mips:
 270   case Triple::mipsel:
 271     FDECFIEncoding = dwarf::DW_EH_PE_sdata4;
 272     break;
 273   case Triple::mips64:
 274   case Triple::mips64el:
 275     FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
 276     break;
 277   default:
 278     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 279     break;
 280   }
 281
 282   switch (T.getArch()) {
 283   case Triple::arm:
 284   case Triple::armeb:
 285   case Triple::thumb:
 286   case Triple::thumbeb:
 287     if (Ctx->getAsmInfo()->getExceptionHandlingType() == ExceptionHandling::ARM)
 288       break;
 289     // Fallthrough if not using EHABI
 290   case Triple::ppc:
 291   case Triple::x86:
 292     PersonalityEncoding = (RelocM == Reloc::PIC_)
 293      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 294      : dwarf::DW_EH_PE_absptr;
 295     LSDAEncoding = (RelocM == Reloc::PIC_)
 296       ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 297       : dwarf::DW_EH_PE_absptr;
 298     TTypeEncoding = (RelocM == Reloc::PIC_)
 299      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 300      : dwarf::DW_EH_PE_absptr;
 301     break;
 302   case Triple::x86_64:
 303     if (RelocM == Reloc::PIC_) {
 304       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 305         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 306          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 307       LSDAEncoding = dwarf::DW_EH_PE_pcrel |
 308         (CMModel == CodeModel::Small
 309          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 310       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 311         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 312          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 313     } else {
 314       PersonalityEncoding =
 315         (CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 316         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 317       LSDAEncoding = (CMModel == CodeModel::Small)
 318         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 319       TTypeEncoding = (CMModel == CodeModel::Small)
 320         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 321     }
 322     break;
 323   case Triple::aarch64:
 324   case Triple::aarch64_be:
 325   case Triple::arm64:
 326   case Triple::arm64_be:
 327     // The small model guarantees static code/data size < 4GB, but not where it
 328     // will be in memory. Most of these could end up >2GB away so even a signed
 329     // pc-relative 32-bit address is insufficient, theoretically.
 330     if (RelocM == Reloc::PIC_) {
 331       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 332         dwarf::DW_EH_PE_sdata8;
 333       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
 334       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 335         dwarf::DW_EH_PE_sdata8;
 336     } else {
 337       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 338       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 339       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 340     }
 341     break;
 342   case Triple::mips:
 343   case Triple::mipsel:
 344   case Triple::mips64:
 345   case Triple::mips64el:
 346     // MIPS uses indirect pointer to refer personality functions, so that the
 347     // eh_frame section can be read-only.  DW.ref.personality will be generated
 348     // for relocation.
 349     PersonalityEncoding = dwarf::DW_EH_PE_indirect;
 350     break;
 351   case Triple::ppc64:
 352   case Triple::ppc64le:
 353     PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 354       dwarf::DW_EH_PE_udata8;
 355     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8;
 356     TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 357       dwarf::DW_EH_PE_udata8;
 358     break;
 359   case Triple::sparc:
 360     if (RelocM == Reloc::PIC_) {
 361       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 362       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 363         dwarf::DW_EH_PE_sdata4;
 364       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 365         dwarf::DW_EH_PE_sdata4;
 366     } else {
 367       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 368       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 369       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 370     }
 371     break;
 372   case Triple::sparcv9:
 373     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 374     if (RelocM == Reloc::PIC_) {
 375       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 376         dwarf::DW_EH_PE_sdata4;
 377       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 378         dwarf::DW_EH_PE_sdata4;
 379     } else {
 380       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 381       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 382     }
 383     break;
 384   case Triple::systemz:
 385     // All currently-defined code models guarantee that 4-byte PC-relative
 386     // values will be in range.
 387     if (RelocM == Reloc::PIC_) {
 388       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 389         dwarf::DW_EH_PE_sdata4;
 390       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 391       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 392         dwarf::DW_EH_PE_sdata4;
 393     } else {
 394       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 395       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 396       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 397     }
 398     break;
 399   default:
 400     break;
 401   }
 402
 403   // Solaris requires different flags for .eh_frame to seemingly every other
 404   // platform.
 405   EHSectionType = ELF::SHT_PROGBITS;
 406   EHSectionFlags = ELF::SHF_ALLOC;
 407   if (T.getOS() == Triple::Solaris) {
 408     if (T.getArch() == Triple::x86_64)
 409       EHSectionType = ELF::SHT_X86_64_UNWIND;
 410     else
 411       EHSectionFlags |= ELF::SHF_WRITE;
 412   }
 413
 414
 415   // ELF
 416   BSSSection =
 417     Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
 418                        ELF::SHF_WRITE | ELF::SHF_ALLOC,
 419                        SectionKind::getBSS());
 420
 421   TextSection =
 422     Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
 423                        ELF::SHF_EXECINSTR |
 424                        ELF::SHF_ALLOC,
 425                        SectionKind::getText());
 426
 427   DataSection =
 428     Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
 429                        ELF::SHF_WRITE |ELF::SHF_ALLOC,
 430                        SectionKind::getDataRel());
 431
 432   ReadOnlySection =
 433     Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS,
 434                        ELF::SHF_ALLOC,
 435                        SectionKind::getReadOnly());
 436
 437   TLSDataSection =
 438     Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
 439                        ELF::SHF_ALLOC | ELF::SHF_TLS |
 440                        ELF::SHF_WRITE,
 441                        SectionKind::getThreadData());
 442
 443   TLSBSSSection =
 444     Ctx->getELFSection(".tbss", ELF::SHT_NOBITS,
 445                        ELF::SHF_ALLOC | ELF::SHF_TLS |
 446                        ELF::SHF_WRITE,
 447                        SectionKind::getThreadBSS());
 448
 449   DataRelSection =
 450     Ctx->getELFSection(".data.rel", ELF::SHT_PROGBITS,
 451                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 452                        SectionKind::getDataRel());
 453
 454   DataRelLocalSection =
 455     Ctx->getELFSection(".data.rel.local", ELF::SHT_PROGBITS,
 456                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 457                        SectionKind::getDataRelLocal());
 458
 459   DataRelROSection =
 460     Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
 461                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 462                        SectionKind::getReadOnlyWithRel());
 463
 464   DataRelROLocalSection =
 465     Ctx->getELFSection(".data.rel.ro.local", ELF::SHT_PROGBITS,
 466                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 467                        SectionKind::getReadOnlyWithRelLocal());
 468
 469   MergeableConst4Section =
 470     Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
 471                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
 472                        SectionKind::getMergeableConst4());
 473
 474   MergeableConst8Section =
 475     Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
 476                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
 477                        SectionKind::getMergeableConst8());
 478
 479   MergeableConst16Section =
 480     Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
 481                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
 482                        SectionKind::getMergeableConst16());
 483
 484   StaticCtorSection =
 485     Ctx->getELFSection(".ctors", ELF::SHT_PROGBITS,
 486                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 487                        SectionKind::getDataRel());
 488
 489   StaticDtorSection =
 490     Ctx->getELFSection(".dtors", ELF::SHT_PROGBITS,
 491                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 492                        SectionKind::getDataRel());
 493
 494   // Exception Handling Sections.
 495
 496   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
 497   // it contains relocatable pointers.  In PIC mode, this is probably a big
 498   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
 499   // adjusted or this should be a data section.
 500   LSDASection =
 501     Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
 502                        ELF::SHF_ALLOC,
 503                        SectionKind::getReadOnly());
 504
 505   COFFDebugSymbolsSection = nullptr;
 506
 507   // Debug Info Sections.
 508   DwarfAbbrevSection =
 509     Ctx->getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0,
 510                        SectionKind::getMetadata());
 511   DwarfInfoSection =
 512     Ctx->getELFSection(".debug_info", ELF::SHT_PROGBITS, 0,
 513                        SectionKind::getMetadata());
 514   DwarfLineSection =
 515     Ctx->getELFSection(".debug_line", ELF::SHT_PROGBITS, 0,
 516                        SectionKind::getMetadata());
 517   DwarfFrameSection =
 518     Ctx->getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0,
 519                        SectionKind::getMetadata());
 520   DwarfPubNamesSection =
 521     Ctx->getELFSection(".debug_pubnames", ELF::SHT_PROGBITS, 0,
 522                        SectionKind::getMetadata());
 523   DwarfPubTypesSection =
 524     Ctx->getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0,
 525                        SectionKind::getMetadata());
 526   DwarfGnuPubNamesSection =
 527     Ctx->getELFSection(".debug_gnu_pubnames", ELF::SHT_PROGBITS, 0,
 528                        SectionKind::getMetadata());
 529   DwarfGnuPubTypesSection =
 530     Ctx->getELFSection(".debug_gnu_pubtypes", ELF::SHT_PROGBITS, 0,
 531                        SectionKind::getMetadata());
 532   DwarfStrSection =
 533     Ctx->getELFSection(".debug_str", ELF::SHT_PROGBITS,
 534                        ELF::SHF_MERGE | ELF::SHF_STRINGS,
 535                        SectionKind::getMergeable1ByteCString());
 536   DwarfLocSection =
 537     Ctx->getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0,
 538                        SectionKind::getMetadata());
 539   DwarfARangesSection =
 540     Ctx->getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0,
 541                        SectionKind::getMetadata());
 542   DwarfRangesSection =
 543     Ctx->getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0,
 544                        SectionKind::getMetadata());
 545   DwarfMacroInfoSection =
 546     Ctx->getELFSection(".debug_macinfo", ELF::SHT_PROGBITS, 0,
 547                        SectionKind::getMetadata());
 548
 549   // DWARF5 Experimental Debug Info
 550
 551   // Accelerator Tables
 552   DwarfAccelNamesSection =
 553     Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0,
 554                        SectionKind::getMetadata());
 555   DwarfAccelObjCSection =
 556     Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0,
 557                        SectionKind::getMetadata());
 558   DwarfAccelNamespaceSection =
 559     Ctx->getELFSection(".apple_namespaces", ELF::SHT_PROGBITS, 0,
 560                        SectionKind::getMetadata());
 561   DwarfAccelTypesSection =
 562     Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0,
 563                        SectionKind::getMetadata());
 564
 565   // Fission Sections
 566   DwarfInfoDWOSection =
 567     Ctx->getELFSection(".debug_info.dwo", ELF::SHT_PROGBITS, 0,
 568                        SectionKind::getMetadata());
 569   DwarfAbbrevDWOSection =
 570     Ctx->getELFSection(".debug_abbrev.dwo", ELF::SHT_PROGBITS, 0,
 571                        SectionKind::getMetadata());
 572   DwarfStrDWOSection =
 573     Ctx->getELFSection(".debug_str.dwo", ELF::SHT_PROGBITS,
 574                        ELF::SHF_MERGE | ELF::SHF_STRINGS,
 575                        SectionKind::getMergeable1ByteCString());
 576   DwarfLineDWOSection =
 577     Ctx->getELFSection(".debug_line.dwo", ELF::SHT_PROGBITS, 0,
 578                        SectionKind::getMetadata());
 579   DwarfLocDWOSection =
 580     Ctx->getELFSection(".debug_loc.dwo", ELF::SHT_PROGBITS, 0,
 581                        SectionKind::getMetadata());
 582   DwarfStrOffDWOSection =
 583     Ctx->getELFSection(".debug_str_offsets.dwo", ELF::SHT_PROGBITS, 0,
 584                        SectionKind::getMetadata());
 585   DwarfAddrSection =
 586     Ctx->getELFSection(".debug_addr", ELF::SHT_PROGBITS, 0,
 587                        SectionKind::getMetadata());
 588 }
 589
 590
 591 void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
 592   bool IsWoA = T.getArch() == Triple::arm || T.getArch() == Triple::thumb;
 593
 594   // The object file format cannot represent common symbols with explicit
 595   // alignments.
 596   CommDirectiveSupportsAlignment = false;
 597
 598   // COFF
 599   BSSSection =
 600     Ctx->getCOFFSection(".bss",
 601                         COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
 602                         COFF::IMAGE_SCN_MEM_READ |
 603                         COFF::IMAGE_SCN_MEM_WRITE,
 604                         SectionKind::getBSS());
 605   TextSection =
 606     Ctx->getCOFFSection(".text",
 607                         (IsWoA ? COFF::IMAGE_SCN_MEM_16BIT
 608                                : (COFF::SectionCharacteristics)0) |
 609                         COFF::IMAGE_SCN_CNT_CODE |
 610                         COFF::IMAGE_SCN_MEM_EXECUTE |
 611                         COFF::IMAGE_SCN_MEM_READ,
 612                         SectionKind::getText());
 613   DataSection =
 614     Ctx->getCOFFSection(".data",
 615                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 616                         COFF::IMAGE_SCN_MEM_READ |
 617                         COFF::IMAGE_SCN_MEM_WRITE,
 618                         SectionKind::getDataRel());
 619   ReadOnlySection =
 620     Ctx->getCOFFSection(".rdata",
 621                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 622                         COFF::IMAGE_SCN_MEM_READ,
 623                         SectionKind::getReadOnly());
 624
 625   if (T.isKnownWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) {
 626     StaticCtorSection =
 627       Ctx->getCOFFSection(".CRT$XCU",
 628                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 629                           COFF::IMAGE_SCN_MEM_READ,
 630                           SectionKind::getReadOnly());
 631     StaticDtorSection =
 632       Ctx->getCOFFSection(".CRT$XTX",
 633                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 634                           COFF::IMAGE_SCN_MEM_READ,
 635                           SectionKind::getReadOnly());
 636   } else {
 637     StaticCtorSection =
 638       Ctx->getCOFFSection(".ctors",
 639                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 640                           COFF::IMAGE_SCN_MEM_READ |
 641                           COFF::IMAGE_SCN_MEM_WRITE,
 642                           SectionKind::getDataRel());
 643     StaticDtorSection =
 644       Ctx->getCOFFSection(".dtors",
 645                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 646                           COFF::IMAGE_SCN_MEM_READ |
 647                           COFF::IMAGE_SCN_MEM_WRITE,
 648                           SectionKind::getDataRel());
 649   }
 650
 651   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
 652   // though it contains relocatable pointers.  In PIC mode, this is probably a
 653   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
 654   // adjusted or this should be a data section.
 655   assert(T.isOSWindows() && "Windows is the only supported COFF target");
 656   if (T.getArch() == Triple::x86_64) {
 657     // On Windows 64 with SEH, the LSDA is emitted into the .xdata section
 658     LSDASection = 0;
 659   } else {
 660     LSDASection = Ctx->getCOFFSection(".gcc_except_table",
 661                                       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 662                                           COFF::IMAGE_SCN_MEM_READ,
 663                                       SectionKind::getReadOnly());
 664   }
 665
 666   // Debug info.
 667   COFFDebugSymbolsSection =
 668     Ctx->getCOFFSection(".debug$S",
 669                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 670                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 671                         COFF::IMAGE_SCN_MEM_READ,
 672                         SectionKind::getMetadata());
 673
 674   DwarfAbbrevSection =
 675     Ctx->getCOFFSection(".debug_abbrev",
 676                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 677                         COFF::IMAGE_SCN_MEM_READ,
 678                         SectionKind::getMetadata());
 679   DwarfInfoSection =
 680     Ctx->getCOFFSection(".debug_info",
 681                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 682                         COFF::IMAGE_SCN_MEM_READ,
 683                         SectionKind::getMetadata());
 684   DwarfLineSection =
 685     Ctx->getCOFFSection(".debug_line",
 686                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 687                         COFF::IMAGE_SCN_MEM_READ,
 688                         SectionKind::getMetadata());
 689   DwarfFrameSection =
 690     Ctx->getCOFFSection(".debug_frame",
 691                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 692                         COFF::IMAGE_SCN_MEM_READ,
 693                         SectionKind::getMetadata());
 694   DwarfPubNamesSection =
 695     Ctx->getCOFFSection(".debug_pubnames",
 696                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 697                         COFF::IMAGE_SCN_MEM_READ,
 698                         SectionKind::getMetadata());
 699   DwarfPubTypesSection =
 700     Ctx->getCOFFSection(".debug_pubtypes",
 701                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 702                         COFF::IMAGE_SCN_MEM_READ,
 703                         SectionKind::getMetadata());
 704   DwarfGnuPubNamesSection =
 705     Ctx->getCOFFSection(".debug_gnu_pubnames",
 706                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 707                         COFF::IMAGE_SCN_MEM_READ,
 708                         SectionKind::getMetadata());
 709   DwarfGnuPubTypesSection =
 710     Ctx->getCOFFSection(".debug_gnu_pubtypes",
 711                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 712                         COFF::IMAGE_SCN_MEM_READ,
 713                         SectionKind::getMetadata());
 714   DwarfStrSection =
 715     Ctx->getCOFFSection(".debug_str",
 716                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 717                         COFF::IMAGE_SCN_MEM_READ,
 718                         SectionKind::getMetadata());
 719   DwarfLocSection =
 720     Ctx->getCOFFSection(".debug_loc",
 721                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 722                         COFF::IMAGE_SCN_MEM_READ,
 723                         SectionKind::getMetadata());
 724   DwarfARangesSection =
 725     Ctx->getCOFFSection(".debug_aranges",
 726                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 727                         COFF::IMAGE_SCN_MEM_READ,
 728                         SectionKind::getMetadata());
 729   DwarfRangesSection =
 730     Ctx->getCOFFSection(".debug_ranges",
 731                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 732                         COFF::IMAGE_SCN_MEM_READ,
 733                         SectionKind::getMetadata());
 734   DwarfMacroInfoSection =
 735     Ctx->getCOFFSection(".debug_macinfo",
 736                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 737                         COFF::IMAGE_SCN_MEM_READ,
 738                         SectionKind::getMetadata());
 739   DwarfInfoDWOSection =
 740       Ctx->getCOFFSection(".debug_info.dwo",
 741                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 742                           COFF::IMAGE_SCN_MEM_READ,
 743                           SectionKind::getMetadata());
 744   DwarfAbbrevDWOSection =
 745       Ctx->getCOFFSection(".debug_abbrev.dwo",
 746                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 747                           COFF::IMAGE_SCN_MEM_READ,
 748                           SectionKind::getMetadata());
 749   DwarfStrDWOSection =
 750       Ctx->getCOFFSection(".debug_str.dwo",
 751                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 752                           COFF::IMAGE_SCN_MEM_READ,
 753                           SectionKind::getMetadata());
 754   DwarfLineDWOSection =
 755       Ctx->getCOFFSection(".debug_line.dwo",
 756                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 757                           COFF::IMAGE_SCN_MEM_READ,
 758                           SectionKind::getMetadata());
 759   DwarfLocDWOSection =
 760       Ctx->getCOFFSection(".debug_loc.dwo",
 761                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 762                           COFF::IMAGE_SCN_MEM_READ,
 763                           SectionKind::getMetadata());
 764   DwarfStrOffDWOSection =
 765       Ctx->getCOFFSection(".debug_str_offsets.dwo",
 766                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 767                           COFF::IMAGE_SCN_MEM_READ,
 768                           SectionKind::getMetadata());
 769
 770   DwarfAddrSection =
 771     Ctx->getCOFFSection(".debug_addr",
 772                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 773                         COFF::IMAGE_SCN_MEM_READ,
 774                         SectionKind::getMetadata());
 775
 776   DrectveSection =
 777     Ctx->getCOFFSection(".drectve",
 778                         COFF::IMAGE_SCN_LNK_INFO |
 779                         COFF::IMAGE_SCN_LNK_REMOVE,
 780                         SectionKind::getMetadata());
 781
 782   PDataSection =
 783     Ctx->getCOFFSection(".pdata",
 784                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 785                         COFF::IMAGE_SCN_MEM_READ,
 786                         SectionKind::getDataRel());
 787
 788   XDataSection =
 789     Ctx->getCOFFSection(".xdata",
 790                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 791                         COFF::IMAGE_SCN_MEM_READ,
 792                         SectionKind::getDataRel());
 793
 794   TLSDataSection =
 795     Ctx->getCOFFSection(".tls$",
 796                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 797                         COFF::IMAGE_SCN_MEM_READ |
 798                         COFF::IMAGE_SCN_MEM_WRITE,
 799                         SectionKind::getDataRel());
 800 }
 801
 802 void MCObjectFileInfo::InitMCObjectFileInfo(StringRef T, Reloc::Model relocm,
 803                                             CodeModel::Model cm,
 804                                             MCContext &ctx) {
 805   RelocM = relocm;
 806   CMModel = cm;
 807   Ctx = &ctx;
 808
 809   // Common.
 810   CommDirectiveSupportsAlignment = true;
 811   SupportsWeakOmittedEHFrame = true;
 812   SupportsCompactUnwindWithoutEHFrame = false;
 813
 814   PersonalityEncoding = LSDAEncoding = FDECFIEncoding = TTypeEncoding =
 815       dwarf::DW_EH_PE_absptr;
 816
 817   CompactUnwindDwarfEHFrameOnly = 0;
 818
 819   EHFrameSection = nullptr;             // Created on demand.
 820   CompactUnwindSection = nullptr;       // Used only by selected targets.
 821   DwarfAccelNamesSection = nullptr;     // Used only by selected targets.
 822   DwarfAccelObjCSection = nullptr;      // Used only by selected targets.
 823   DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
 824   DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
 825
 826   TT = Triple(T);
 827
 828   Triple::ArchType Arch = TT.getArch();
 829   // FIXME: Checking for Arch here to filter out bogus triples such as
 830   // cellspu-apple-darwin. Perhaps we should fix in Triple?
 831   if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
 832        Arch == Triple::arm || Arch == Triple::thumb ||
 833        Arch == Triple::arm64 || Arch == Triple::aarch64 ||
 834        Arch == Triple::ppc || Arch == Triple::ppc64 ||
 835        Arch == Triple::UnknownArch) &&
 836       (TT.isOSDarwin() || TT.isOSBinFormatMachO())) {
 837     Env = IsMachO;
 838     InitMachOMCObjectFileInfo(TT);
 839   } else if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
 840               Arch == Triple::arm || Arch == Triple::thumb) &&
 841              (TT.isOSWindows() && TT.getObjectFormat() == Triple::COFF)) {
 842     Env = IsCOFF;
 843     InitCOFFMCObjectFileInfo(TT);
 844   } else {
 845     Env = IsELF;
 846     InitELFMCObjectFileInfo(TT);
 847   }
 848 }
 849
 850 const MCSection *MCObjectFileInfo::getDwarfTypesSection(uint64_t Hash) const {
 851   return Ctx->getELFSection(".debug_types", ELF::SHT_PROGBITS, ELF::SHF_GROUP,
 852                             SectionKind::getMetadata(), 0, utostr(Hash));
 853 }
 854
 855 const MCSection *
 856 MCObjectFileInfo::getDwarfTypesDWOSection(uint64_t Hash) const {
 857   return Ctx->getELFSection(".debug_types.dwo", ELF::SHT_PROGBITS,
 858                             ELF::SHF_GROUP, SectionKind::getMetadata(), 0,
 859                             utostr(Hash));
 860 }
 861
 862 void MCObjectFileInfo::InitEHFrameSection() {
 863   if (Env == IsMachO)
 864     EHFrameSection =
 865       Ctx->getMachOSection("__TEXT", "__eh_frame",
 866                            MachO::S_COALESCED |
 867                            MachO::S_ATTR_NO_TOC |
 868                            MachO::S_ATTR_STRIP_STATIC_SYMS |
 869                            MachO::S_ATTR_LIVE_SUPPORT,
 870                            SectionKind::getReadOnly());
 871   else if (Env == IsELF)
 872     EHFrameSection =
 873       Ctx->getELFSection(".eh_frame", EHSectionType,
 874                          EHSectionFlags,
 875                          SectionKind::getDataRel());
 876   else
 877     EHFrameSection =
 878       Ctx->getCOFFSection(".eh_frame",
 879                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 880                           COFF::IMAGE_SCN_MEM_READ |
 881                           COFF::IMAGE_SCN_MEM_WRITE,
 882                           SectionKind::getDataRel());
 883 }