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   DwarfAbbrevDWOSection =
 565     Ctx->getELFSection(".debug_abbrev.dwo", ELF::SHT_PROGBITS, 0,
 566                        SectionKind::getMetadata());
 567   DwarfStrDWOSection =
 568     Ctx->getELFSection(".debug_str.dwo", ELF::SHT_PROGBITS,
 569                        ELF::SHF_MERGE | ELF::SHF_STRINGS,
 570                        SectionKind::getMergeable1ByteCString());
 571   DwarfLineDWOSection =
 572     Ctx->getELFSection(".debug_line.dwo", ELF::SHT_PROGBITS, 0,
 573                        SectionKind::getMetadata());
 574   DwarfLocDWOSection =
 575     Ctx->getELFSection(".debug_loc.dwo", ELF::SHT_PROGBITS, 0,
 576                        SectionKind::getMetadata());
 577   DwarfStrOffDWOSection =
 578     Ctx->getELFSection(".debug_str_offsets.dwo", ELF::SHT_PROGBITS, 0,
 579                        SectionKind::getMetadata());
 580   DwarfAddrSection =
 581     Ctx->getELFSection(".debug_addr", ELF::SHT_PROGBITS, 0,
 582                        SectionKind::getMetadata());
 583 }
 584
 585
 586 void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
 587   bool IsWoA = T.getArch() == Triple::arm || T.getArch() == Triple::thumb;
 588
 589   // The object file format cannot represent common symbols with explicit
 590   // alignments.
 591   CommDirectiveSupportsAlignment = false;
 592
 593   // COFF
 594   BSSSection =
 595     Ctx->getCOFFSection(".bss",
 596                         COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
 597                         COFF::IMAGE_SCN_MEM_READ |
 598                         COFF::IMAGE_SCN_MEM_WRITE,
 599                         SectionKind::getBSS());
 600   TextSection =
 601     Ctx->getCOFFSection(".text",
 602                         (IsWoA ? COFF::IMAGE_SCN_MEM_16BIT
 603                                : (COFF::SectionCharacteristics)0) |
 604                         COFF::IMAGE_SCN_CNT_CODE |
 605                         COFF::IMAGE_SCN_MEM_EXECUTE |
 606                         COFF::IMAGE_SCN_MEM_READ,
 607                         SectionKind::getText());
 608   DataSection =
 609     Ctx->getCOFFSection(".data",
 610                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 611                         COFF::IMAGE_SCN_MEM_READ |
 612                         COFF::IMAGE_SCN_MEM_WRITE,
 613                         SectionKind::getDataRel());
 614   ReadOnlySection =
 615     Ctx->getCOFFSection(".rdata",
 616                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 617                         COFF::IMAGE_SCN_MEM_READ,
 618                         SectionKind::getReadOnly());
 619
 620   if (T.isKnownWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) {
 621     StaticCtorSection =
 622       Ctx->getCOFFSection(".CRT$XCU",
 623                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 624                           COFF::IMAGE_SCN_MEM_READ,
 625                           SectionKind::getReadOnly());
 626     StaticDtorSection =
 627       Ctx->getCOFFSection(".CRT$XTX",
 628                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 629                           COFF::IMAGE_SCN_MEM_READ,
 630                           SectionKind::getReadOnly());
 631   } else {
 632     StaticCtorSection =
 633       Ctx->getCOFFSection(".ctors",
 634                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 635                           COFF::IMAGE_SCN_MEM_READ |
 636                           COFF::IMAGE_SCN_MEM_WRITE,
 637                           SectionKind::getDataRel());
 638     StaticDtorSection =
 639       Ctx->getCOFFSection(".dtors",
 640                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 641                           COFF::IMAGE_SCN_MEM_READ |
 642                           COFF::IMAGE_SCN_MEM_WRITE,
 643                           SectionKind::getDataRel());
 644   }
 645
 646   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
 647   // though it contains relocatable pointers.  In PIC mode, this is probably a
 648   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
 649   // adjusted or this should be a data section.
 650   assert(T.isOSWindows() && "Windows is the only supported COFF target");
 651   if (T.getArch() == Triple::x86_64) {
 652     // On Windows 64 with SEH, the LSDA is emitted into the .xdata section
 653     LSDASection = 0;
 654   } else {
 655     LSDASection = Ctx->getCOFFSection(".gcc_except_table",
 656                                       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 657                                           COFF::IMAGE_SCN_MEM_READ,
 658                                       SectionKind::getReadOnly());
 659   }
 660
 661   // Debug info.
 662   COFFDebugSymbolsSection =
 663     Ctx->getCOFFSection(".debug$S",
 664                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 665                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 666                         COFF::IMAGE_SCN_MEM_READ,
 667                         SectionKind::getMetadata());
 668
 669   DwarfAbbrevSection =
 670     Ctx->getCOFFSection(".debug_abbrev",
 671                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 672                         COFF::IMAGE_SCN_MEM_READ,
 673                         SectionKind::getMetadata());
 674   DwarfInfoSection =
 675     Ctx->getCOFFSection(".debug_info",
 676                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 677                         COFF::IMAGE_SCN_MEM_READ,
 678                         SectionKind::getMetadata());
 679   DwarfLineSection =
 680     Ctx->getCOFFSection(".debug_line",
 681                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 682                         COFF::IMAGE_SCN_MEM_READ,
 683                         SectionKind::getMetadata());
 684   DwarfFrameSection =
 685     Ctx->getCOFFSection(".debug_frame",
 686                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 687                         COFF::IMAGE_SCN_MEM_READ,
 688                         SectionKind::getMetadata());
 689   DwarfPubNamesSection =
 690     Ctx->getCOFFSection(".debug_pubnames",
 691                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 692                         COFF::IMAGE_SCN_MEM_READ,
 693                         SectionKind::getMetadata());
 694   DwarfPubTypesSection =
 695     Ctx->getCOFFSection(".debug_pubtypes",
 696                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 697                         COFF::IMAGE_SCN_MEM_READ,
 698                         SectionKind::getMetadata());
 699   DwarfGnuPubNamesSection =
 700     Ctx->getCOFFSection(".debug_gnu_pubnames",
 701                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 702                         COFF::IMAGE_SCN_MEM_READ,
 703                         SectionKind::getMetadata());
 704   DwarfGnuPubTypesSection =
 705     Ctx->getCOFFSection(".debug_gnu_pubtypes",
 706                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 707                         COFF::IMAGE_SCN_MEM_READ,
 708                         SectionKind::getMetadata());
 709   DwarfStrSection =
 710     Ctx->getCOFFSection(".debug_str",
 711                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 712                         COFF::IMAGE_SCN_MEM_READ,
 713                         SectionKind::getMetadata());
 714   DwarfLocSection =
 715     Ctx->getCOFFSection(".debug_loc",
 716                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 717                         COFF::IMAGE_SCN_MEM_READ,
 718                         SectionKind::getMetadata());
 719   DwarfARangesSection =
 720     Ctx->getCOFFSection(".debug_aranges",
 721                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 722                         COFF::IMAGE_SCN_MEM_READ,
 723                         SectionKind::getMetadata());
 724   DwarfRangesSection =
 725     Ctx->getCOFFSection(".debug_ranges",
 726                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 727                         COFF::IMAGE_SCN_MEM_READ,
 728                         SectionKind::getMetadata());
 729   DwarfMacroInfoSection =
 730     Ctx->getCOFFSection(".debug_macinfo",
 731                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 732                         COFF::IMAGE_SCN_MEM_READ,
 733                         SectionKind::getMetadata());
 734   DwarfInfoDWOSection =
 735       Ctx->getCOFFSection(".debug_info.dwo",
 736                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 737                           COFF::IMAGE_SCN_MEM_READ,
 738                           SectionKind::getMetadata());
 739   DwarfAbbrevDWOSection =
 740       Ctx->getCOFFSection(".debug_abbrev.dwo",
 741                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 742                           COFF::IMAGE_SCN_MEM_READ,
 743                           SectionKind::getMetadata());
 744   DwarfStrDWOSection =
 745       Ctx->getCOFFSection(".debug_str.dwo",
 746                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 747                           COFF::IMAGE_SCN_MEM_READ,
 748                           SectionKind::getMetadata());
 749   DwarfLineDWOSection =
 750       Ctx->getCOFFSection(".debug_line.dwo",
 751                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 752                           COFF::IMAGE_SCN_MEM_READ,
 753                           SectionKind::getMetadata());
 754   DwarfLocDWOSection =
 755       Ctx->getCOFFSection(".debug_loc.dwo",
 756                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 757                           COFF::IMAGE_SCN_MEM_READ,
 758                           SectionKind::getMetadata());
 759   DwarfStrOffDWOSection =
 760       Ctx->getCOFFSection(".debug_str_offsets.dwo",
 761                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 762                           COFF::IMAGE_SCN_MEM_READ,
 763                           SectionKind::getMetadata());
 764
 765   DwarfAddrSection =
 766     Ctx->getCOFFSection(".debug_addr",
 767                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 768                         COFF::IMAGE_SCN_MEM_READ,
 769                         SectionKind::getMetadata());
 770
 771   DrectveSection =
 772     Ctx->getCOFFSection(".drectve",
 773                         COFF::IMAGE_SCN_LNK_INFO |
 774                         COFF::IMAGE_SCN_LNK_REMOVE,
 775                         SectionKind::getMetadata());
 776
 777   PDataSection =
 778     Ctx->getCOFFSection(".pdata",
 779                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 780                         COFF::IMAGE_SCN_MEM_READ,
 781                         SectionKind::getDataRel());
 782
 783   XDataSection =
 784     Ctx->getCOFFSection(".xdata",
 785                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 786                         COFF::IMAGE_SCN_MEM_READ,
 787                         SectionKind::getDataRel());
 788
 789   TLSDataSection =
 790     Ctx->getCOFFSection(".tls$",
 791                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 792                         COFF::IMAGE_SCN_MEM_READ |
 793                         COFF::IMAGE_SCN_MEM_WRITE,
 794                         SectionKind::getDataRel());
 795 }
 796
 797 void MCObjectFileInfo::InitMCObjectFileInfo(StringRef T, Reloc::Model relocm,
 798                                             CodeModel::Model cm,
 799                                             MCContext &ctx) {
 800   RelocM = relocm;
 801   CMModel = cm;
 802   Ctx = &ctx;
 803
 804   // Common.
 805   CommDirectiveSupportsAlignment = true;
 806   SupportsWeakOmittedEHFrame = true;
 807   SupportsCompactUnwindWithoutEHFrame = false;
 808
 809   PersonalityEncoding = LSDAEncoding = FDECFIEncoding = TTypeEncoding =
 810       dwarf::DW_EH_PE_absptr;
 811
 812   CompactUnwindDwarfEHFrameOnly = 0;
 813
 814   EHFrameSection = nullptr;             // Created on demand.
 815   CompactUnwindSection = nullptr;       // Used only by selected targets.
 816   DwarfAccelNamesSection = nullptr;     // Used only by selected targets.
 817   DwarfAccelObjCSection = nullptr;      // Used only by selected targets.
 818   DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
 819   DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
 820
 821   TT = Triple(T);
 822
 823   Triple::ArchType Arch = TT.getArch();
 824   // FIXME: Checking for Arch here to filter out bogus triples such as
 825   // cellspu-apple-darwin. Perhaps we should fix in Triple?
 826   if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
 827        Arch == Triple::arm || Arch == Triple::thumb ||
 828        Arch == Triple::aarch64 ||
 829        Arch == Triple::ppc || Arch == Triple::ppc64 ||
 830        Arch == Triple::UnknownArch) &&
 831       (TT.isOSDarwin() || TT.isOSBinFormatMachO())) {
 832     Env = IsMachO;
 833     InitMachOMCObjectFileInfo(TT);
 834   } else if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
 835               Arch == Triple::arm || Arch == Triple::thumb) &&
 836              (TT.isOSWindows() && TT.getObjectFormat() == Triple::COFF)) {
 837     Env = IsCOFF;
 838     InitCOFFMCObjectFileInfo(TT);
 839   } else {
 840     Env = IsELF;
 841     InitELFMCObjectFileInfo(TT);
 842   }
 843 }
 844
 845 const MCSection *MCObjectFileInfo::getDwarfTypesSection(uint64_t Hash) const {
 846   return Ctx->getELFSection(".debug_types", ELF::SHT_PROGBITS, ELF::SHF_GROUP,
 847                             SectionKind::getMetadata(), 0, utostr(Hash));
 848 }
 849
 850 const MCSection *
 851 MCObjectFileInfo::getDwarfTypesDWOSection(uint64_t Hash) const {
 852   return Ctx->getELFSection(".debug_types.dwo", ELF::SHT_PROGBITS,
 853                             ELF::SHF_GROUP, SectionKind::getMetadata(), 0,
 854                             utostr(Hash));
 855 }
 856
 857 void MCObjectFileInfo::InitEHFrameSection() {
 858   if (Env == IsMachO)
 859     EHFrameSection =
 860       Ctx->getMachOSection("__TEXT", "__eh_frame",
 861                            MachO::S_COALESCED |
 862                            MachO::S_ATTR_NO_TOC |
 863                            MachO::S_ATTR_STRIP_STATIC_SYMS |
 864                            MachO::S_ATTR_LIVE_SUPPORT,
 865                            SectionKind::getReadOnly());
 866   else if (Env == IsELF)
 867     EHFrameSection =
 868       Ctx->getELFSection(".eh_frame", EHSectionType,
 869                          EHSectionFlags,
 870                          SectionKind::getDataRel());
 871   else
 872     EHFrameSection =
 873       Ctx->getCOFFSection(".eh_frame",
 874                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 875                           COFF::IMAGE_SCN_MEM_READ |
 876                           COFF::IMAGE_SCN_MEM_WRITE,
 877                           SectionKind::getDataRel());
 878 }