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