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::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   case Triple::arm64:
 325   case Triple::arm64_be:
 326     // The small model guarantees static code/data size < 4GB, but not where it
 327     // will be in memory. Most of these could end up >2GB away so even a signed
 328     // pc-relative 32-bit address is insufficient, theoretically.
 329     if (RelocM == Reloc::PIC_) {
 330       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 331         dwarf::DW_EH_PE_sdata8;
 332       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
 333       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 334         dwarf::DW_EH_PE_sdata8;
 335     } else {
 336       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 337       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 338       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 339     }
 340     break;
 341   case Triple::mips:
 342   case Triple::mipsel:
 343     // MIPS uses indirect pointer to refer personality functions, so that the
 344     // eh_frame section can be read-only.  DW.ref.personality will be generated
 345     // for relocation.
 346     PersonalityEncoding = dwarf::DW_EH_PE_indirect;
 347     break;
 348   case Triple::ppc64:
 349   case Triple::ppc64le:
 350     PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 351       dwarf::DW_EH_PE_udata8;
 352     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8;
 353     TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 354       dwarf::DW_EH_PE_udata8;
 355     break;
 356   case Triple::sparc:
 357     if (RelocM == Reloc::PIC_) {
 358       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 359       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 360         dwarf::DW_EH_PE_sdata4;
 361       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 362         dwarf::DW_EH_PE_sdata4;
 363     } else {
 364       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 365       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 366       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 367     }
 368     break;
 369   case Triple::sparcv9:
 370     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 371     if (RelocM == Reloc::PIC_) {
 372       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 373         dwarf::DW_EH_PE_sdata4;
 374       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 375         dwarf::DW_EH_PE_sdata4;
 376     } else {
 377       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 378       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 379     }
 380     break;
 381   case Triple::systemz:
 382     // All currently-defined code models guarantee that 4-byte PC-relative
 383     // values will be in range.
 384     if (RelocM == Reloc::PIC_) {
 385       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 386         dwarf::DW_EH_PE_sdata4;
 387       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 388       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 389         dwarf::DW_EH_PE_sdata4;
 390     } else {
 391       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 392       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 393       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 394     }
 395     break;
 396   default:
 397     break;
 398   }
 399
 400   // Solaris requires different flags for .eh_frame to seemingly every other
 401   // platform.
 402   EHSectionType = ELF::SHT_PROGBITS;
 403   EHSectionFlags = ELF::SHF_ALLOC;
 404   if (T.getOS() == Triple::Solaris) {
 405     if (T.getArch() == Triple::x86_64)
 406       EHSectionType = ELF::SHT_X86_64_UNWIND;
 407     else
 408       EHSectionFlags |= ELF::SHF_WRITE;
 409   }
 410
 411
 412   // ELF
 413   BSSSection =
 414     Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
 415                        ELF::SHF_WRITE | ELF::SHF_ALLOC,
 416                        SectionKind::getBSS());
 417
 418   TextSection =
 419     Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
 420                        ELF::SHF_EXECINSTR |
 421                        ELF::SHF_ALLOC,
 422                        SectionKind::getText());
 423
 424   DataSection =
 425     Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
 426                        ELF::SHF_WRITE |ELF::SHF_ALLOC,
 427                        SectionKind::getDataRel());
 428
 429   ReadOnlySection =
 430     Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS,
 431                        ELF::SHF_ALLOC,
 432                        SectionKind::getReadOnly());
 433
 434   TLSDataSection =
 435     Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
 436                        ELF::SHF_ALLOC | ELF::SHF_TLS |
 437                        ELF::SHF_WRITE,
 438                        SectionKind::getThreadData());
 439
 440   TLSBSSSection =
 441     Ctx->getELFSection(".tbss", ELF::SHT_NOBITS,
 442                        ELF::SHF_ALLOC | ELF::SHF_TLS |
 443                        ELF::SHF_WRITE,
 444                        SectionKind::getThreadBSS());
 445
 446   DataRelSection =
 447     Ctx->getELFSection(".data.rel", ELF::SHT_PROGBITS,
 448                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 449                        SectionKind::getDataRel());
 450
 451   DataRelLocalSection =
 452     Ctx->getELFSection(".data.rel.local", ELF::SHT_PROGBITS,
 453                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 454                        SectionKind::getDataRelLocal());
 455
 456   DataRelROSection =
 457     Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
 458                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 459                        SectionKind::getReadOnlyWithRel());
 460
 461   DataRelROLocalSection =
 462     Ctx->getELFSection(".data.rel.ro.local", ELF::SHT_PROGBITS,
 463                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 464                        SectionKind::getReadOnlyWithRelLocal());
 465
 466   MergeableConst4Section =
 467     Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
 468                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
 469                        SectionKind::getMergeableConst4());
 470
 471   MergeableConst8Section =
 472     Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
 473                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
 474                        SectionKind::getMergeableConst8());
 475
 476   MergeableConst16Section =
 477     Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
 478                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
 479                        SectionKind::getMergeableConst16());
 480
 481   StaticCtorSection =
 482     Ctx->getELFSection(".ctors", ELF::SHT_PROGBITS,
 483                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 484                        SectionKind::getDataRel());
 485
 486   StaticDtorSection =
 487     Ctx->getELFSection(".dtors", ELF::SHT_PROGBITS,
 488                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
 489                        SectionKind::getDataRel());
 490
 491   // Exception Handling Sections.
 492
 493   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
 494   // it contains relocatable pointers.  In PIC mode, this is probably a big
 495   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
 496   // adjusted or this should be a data section.
 497   LSDASection =
 498     Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
 499                        ELF::SHF_ALLOC,
 500                        SectionKind::getReadOnly());
 501
 502   COFFDebugSymbolsSection = nullptr;
 503
 504   // Debug Info Sections.
 505   DwarfAbbrevSection =
 506     Ctx->getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0,
 507                        SectionKind::getMetadata());
 508   DwarfInfoSection =
 509     Ctx->getELFSection(".debug_info", ELF::SHT_PROGBITS, 0,
 510                        SectionKind::getMetadata());
 511   DwarfLineSection =
 512     Ctx->getELFSection(".debug_line", ELF::SHT_PROGBITS, 0,
 513                        SectionKind::getMetadata());
 514   DwarfFrameSection =
 515     Ctx->getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0,
 516                        SectionKind::getMetadata());
 517   DwarfPubNamesSection =
 518     Ctx->getELFSection(".debug_pubnames", ELF::SHT_PROGBITS, 0,
 519                        SectionKind::getMetadata());
 520   DwarfPubTypesSection =
 521     Ctx->getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0,
 522                        SectionKind::getMetadata());
 523   DwarfGnuPubNamesSection =
 524     Ctx->getELFSection(".debug_gnu_pubnames", ELF::SHT_PROGBITS, 0,
 525                        SectionKind::getMetadata());
 526   DwarfGnuPubTypesSection =
 527     Ctx->getELFSection(".debug_gnu_pubtypes", ELF::SHT_PROGBITS, 0,
 528                        SectionKind::getMetadata());
 529   DwarfStrSection =
 530     Ctx->getELFSection(".debug_str", ELF::SHT_PROGBITS,
 531                        ELF::SHF_MERGE | ELF::SHF_STRINGS,
 532                        SectionKind::getMergeable1ByteCString());
 533   DwarfLocSection =
 534     Ctx->getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0,
 535                        SectionKind::getMetadata());
 536   DwarfARangesSection =
 537     Ctx->getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0,
 538                        SectionKind::getMetadata());
 539   DwarfRangesSection =
 540     Ctx->getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0,
 541                        SectionKind::getMetadata());
 542   DwarfMacroInfoSection =
 543     Ctx->getELFSection(".debug_macinfo", ELF::SHT_PROGBITS, 0,
 544                        SectionKind::getMetadata());
 545
 546   // DWARF5 Experimental Debug Info
 547
 548   // Accelerator Tables
 549   DwarfAccelNamesSection =
 550     Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0,
 551                        SectionKind::getMetadata());
 552   DwarfAccelObjCSection =
 553     Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0,
 554                        SectionKind::getMetadata());
 555   DwarfAccelNamespaceSection =
 556     Ctx->getELFSection(".apple_namespaces", ELF::SHT_PROGBITS, 0,
 557                        SectionKind::getMetadata());
 558   DwarfAccelTypesSection =
 559     Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0,
 560                        SectionKind::getMetadata());
 561
 562   // Fission Sections
 563   DwarfInfoDWOSection =
 564     Ctx->getELFSection(".debug_info.dwo", ELF::SHT_PROGBITS, 0,
 565                        SectionKind::getMetadata());
 566   DwarfAbbrevDWOSection =
 567     Ctx->getELFSection(".debug_abbrev.dwo", ELF::SHT_PROGBITS, 0,
 568                        SectionKind::getMetadata());
 569   DwarfStrDWOSection =
 570     Ctx->getELFSection(".debug_str.dwo", ELF::SHT_PROGBITS,
 571                        ELF::SHF_MERGE | ELF::SHF_STRINGS,
 572                        SectionKind::getMergeable1ByteCString());
 573   DwarfLineDWOSection =
 574     Ctx->getELFSection(".debug_line.dwo", ELF::SHT_PROGBITS, 0,
 575                        SectionKind::getMetadata());
 576   DwarfLocDWOSection =
 577     Ctx->getELFSection(".debug_loc.dwo", ELF::SHT_PROGBITS, 0,
 578                        SectionKind::getMetadata());
 579   DwarfStrOffDWOSection =
 580     Ctx->getELFSection(".debug_str_offsets.dwo", ELF::SHT_PROGBITS, 0,
 581                        SectionKind::getMetadata());
 582   DwarfAddrSection =
 583     Ctx->getELFSection(".debug_addr", ELF::SHT_PROGBITS, 0,
 584                        SectionKind::getMetadata());
 585 }
 586
 587
 588 void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
 589   bool IsWoA = T.getArch() == Triple::arm || T.getArch() == Triple::thumb;
 590
 591   // The object file format cannot represent common symbols with explicit
 592   // alignments.
 593   CommDirectiveSupportsAlignment = false;
 594
 595   // COFF
 596   BSSSection =
 597     Ctx->getCOFFSection(".bss",
 598                         COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
 599                         COFF::IMAGE_SCN_MEM_READ |
 600                         COFF::IMAGE_SCN_MEM_WRITE,
 601                         SectionKind::getBSS());
 602   TextSection =
 603     Ctx->getCOFFSection(".text",
 604                         (IsWoA ? COFF::IMAGE_SCN_MEM_16BIT
 605                                : (COFF::SectionCharacteristics)0) |
 606                         COFF::IMAGE_SCN_CNT_CODE |
 607                         COFF::IMAGE_SCN_MEM_EXECUTE |
 608                         COFF::IMAGE_SCN_MEM_READ,
 609                         SectionKind::getText());
 610   DataSection =
 611     Ctx->getCOFFSection(".data",
 612                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 613                         COFF::IMAGE_SCN_MEM_READ |
 614                         COFF::IMAGE_SCN_MEM_WRITE,
 615                         SectionKind::getDataRel());
 616   ReadOnlySection =
 617     Ctx->getCOFFSection(".rdata",
 618                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 619                         COFF::IMAGE_SCN_MEM_READ,
 620                         SectionKind::getReadOnly());
 621
 622   if (T.isKnownWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) {
 623     StaticCtorSection =
 624       Ctx->getCOFFSection(".CRT$XCU",
 625                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 626                           COFF::IMAGE_SCN_MEM_READ,
 627                           SectionKind::getReadOnly());
 628     StaticDtorSection =
 629       Ctx->getCOFFSection(".CRT$XTX",
 630                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 631                           COFF::IMAGE_SCN_MEM_READ,
 632                           SectionKind::getReadOnly());
 633   } else {
 634     StaticCtorSection =
 635       Ctx->getCOFFSection(".ctors",
 636                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 637                           COFF::IMAGE_SCN_MEM_READ |
 638                           COFF::IMAGE_SCN_MEM_WRITE,
 639                           SectionKind::getDataRel());
 640     StaticDtorSection =
 641       Ctx->getCOFFSection(".dtors",
 642                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 643                           COFF::IMAGE_SCN_MEM_READ |
 644                           COFF::IMAGE_SCN_MEM_WRITE,
 645                           SectionKind::getDataRel());
 646   }
 647
 648   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
 649   // though it contains relocatable pointers.  In PIC mode, this is probably a
 650   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
 651   // adjusted or this should be a data section.
 652   LSDASection =
 653     Ctx->getCOFFSection(".gcc_except_table",
 654                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 655                         COFF::IMAGE_SCN_MEM_READ,
 656                         SectionKind::getReadOnly());
 657
 658   // Debug info.
 659   COFFDebugSymbolsSection =
 660     Ctx->getCOFFSection(".debug$S",
 661                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 662                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 663                         COFF::IMAGE_SCN_MEM_READ,
 664                         SectionKind::getMetadata());
 665
 666   DwarfAbbrevSection =
 667     Ctx->getCOFFSection(".debug_abbrev",
 668                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 669                         COFF::IMAGE_SCN_MEM_READ,
 670                         SectionKind::getMetadata());
 671   DwarfInfoSection =
 672     Ctx->getCOFFSection(".debug_info",
 673                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 674                         COFF::IMAGE_SCN_MEM_READ,
 675                         SectionKind::getMetadata());
 676   DwarfLineSection =
 677     Ctx->getCOFFSection(".debug_line",
 678                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 679                         COFF::IMAGE_SCN_MEM_READ,
 680                         SectionKind::getMetadata());
 681   DwarfFrameSection =
 682     Ctx->getCOFFSection(".debug_frame",
 683                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 684                         COFF::IMAGE_SCN_MEM_READ,
 685                         SectionKind::getMetadata());
 686   DwarfPubNamesSection =
 687     Ctx->getCOFFSection(".debug_pubnames",
 688                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 689                         COFF::IMAGE_SCN_MEM_READ,
 690                         SectionKind::getMetadata());
 691   DwarfPubTypesSection =
 692     Ctx->getCOFFSection(".debug_pubtypes",
 693                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 694                         COFF::IMAGE_SCN_MEM_READ,
 695                         SectionKind::getMetadata());
 696   DwarfGnuPubNamesSection =
 697     Ctx->getCOFFSection(".debug_gnu_pubnames",
 698                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 699                         COFF::IMAGE_SCN_MEM_READ,
 700                         SectionKind::getMetadata());
 701   DwarfGnuPubTypesSection =
 702     Ctx->getCOFFSection(".debug_gnu_pubtypes",
 703                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 704                         COFF::IMAGE_SCN_MEM_READ,
 705                         SectionKind::getMetadata());
 706   DwarfStrSection =
 707     Ctx->getCOFFSection(".debug_str",
 708                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 709                         COFF::IMAGE_SCN_MEM_READ,
 710                         SectionKind::getMetadata());
 711   DwarfLocSection =
 712     Ctx->getCOFFSection(".debug_loc",
 713                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 714                         COFF::IMAGE_SCN_MEM_READ,
 715                         SectionKind::getMetadata());
 716   DwarfARangesSection =
 717     Ctx->getCOFFSection(".debug_aranges",
 718                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 719                         COFF::IMAGE_SCN_MEM_READ,
 720                         SectionKind::getMetadata());
 721   DwarfRangesSection =
 722     Ctx->getCOFFSection(".debug_ranges",
 723                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 724                         COFF::IMAGE_SCN_MEM_READ,
 725                         SectionKind::getMetadata());
 726   DwarfMacroInfoSection =
 727     Ctx->getCOFFSection(".debug_macinfo",
 728                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 729                         COFF::IMAGE_SCN_MEM_READ,
 730                         SectionKind::getMetadata());
 731   DwarfInfoDWOSection =
 732       Ctx->getCOFFSection(".debug_info.dwo",
 733                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 734                           COFF::IMAGE_SCN_MEM_READ,
 735                           SectionKind::getMetadata());
 736   DwarfAbbrevDWOSection =
 737       Ctx->getCOFFSection(".debug_abbrev.dwo",
 738                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 739                           COFF::IMAGE_SCN_MEM_READ,
 740                           SectionKind::getMetadata());
 741   DwarfStrDWOSection =
 742       Ctx->getCOFFSection(".debug_str.dwo",
 743                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 744                           COFF::IMAGE_SCN_MEM_READ,
 745                           SectionKind::getMetadata());
 746   DwarfLineDWOSection =
 747       Ctx->getCOFFSection(".debug_line.dwo",
 748                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 749                           COFF::IMAGE_SCN_MEM_READ,
 750                           SectionKind::getMetadata());
 751   DwarfLocDWOSection =
 752       Ctx->getCOFFSection(".debug_loc.dwo",
 753                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 754                           COFF::IMAGE_SCN_MEM_READ,
 755                           SectionKind::getMetadata());
 756   DwarfStrOffDWOSection =
 757       Ctx->getCOFFSection(".debug_str_offsets.dwo",
 758                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 759                           COFF::IMAGE_SCN_MEM_READ,
 760                           SectionKind::getMetadata());
 761
 762   DwarfAddrSection =
 763     Ctx->getCOFFSection(".debug_addr",
 764                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 765                         COFF::IMAGE_SCN_MEM_READ,
 766                         SectionKind::getMetadata());
 767
 768   DrectveSection =
 769     Ctx->getCOFFSection(".drectve",
 770                         COFF::IMAGE_SCN_LNK_INFO |
 771                         COFF::IMAGE_SCN_LNK_REMOVE,
 772                         SectionKind::getMetadata());
 773
 774   PDataSection =
 775     Ctx->getCOFFSection(".pdata",
 776                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 777                         COFF::IMAGE_SCN_MEM_READ,
 778                         SectionKind::getDataRel());
 779
 780   XDataSection =
 781     Ctx->getCOFFSection(".xdata",
 782                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 783                         COFF::IMAGE_SCN_MEM_READ,
 784                         SectionKind::getDataRel());
 785
 786   TLSDataSection =
 787     Ctx->getCOFFSection(".tls$",
 788                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 789                         COFF::IMAGE_SCN_MEM_READ |
 790                         COFF::IMAGE_SCN_MEM_WRITE,
 791                         SectionKind::getDataRel());
 792 }
 793
 794 void MCObjectFileInfo::InitMCObjectFileInfo(StringRef T, Reloc::Model relocm,
 795                                             CodeModel::Model cm,
 796                                             MCContext &ctx) {
 797   RelocM = relocm;
 798   CMModel = cm;
 799   Ctx = &ctx;
 800
 801   // Common.
 802   CommDirectiveSupportsAlignment = true;
 803   SupportsWeakOmittedEHFrame = true;
 804   SupportsCompactUnwindWithoutEHFrame = false;
 805
 806   PersonalityEncoding = LSDAEncoding = FDECFIEncoding = TTypeEncoding =
 807       dwarf::DW_EH_PE_absptr;
 808
 809   CompactUnwindDwarfEHFrameOnly = 0;
 810
 811   EHFrameSection = nullptr;             // Created on demand.
 812   CompactUnwindSection = nullptr;       // Used only by selected targets.
 813   DwarfAccelNamesSection = nullptr;     // Used only by selected targets.
 814   DwarfAccelObjCSection = nullptr;      // Used only by selected targets.
 815   DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
 816   DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
 817
 818   TT = Triple(T);
 819
 820   Triple::ArchType Arch = TT.getArch();
 821   // FIXME: Checking for Arch here to filter out bogus triples such as
 822   // cellspu-apple-darwin. Perhaps we should fix in Triple?
 823   if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
 824        Arch == Triple::arm || Arch == Triple::thumb ||
 825        Arch == Triple::arm64 || Arch == Triple::aarch64 ||
 826        Arch == Triple::ppc || Arch == Triple::ppc64 ||
 827        Arch == Triple::UnknownArch) &&
 828       (TT.isOSDarwin() || TT.isOSBinFormatMachO())) {
 829     Env = IsMachO;
 830     InitMachOMCObjectFileInfo(TT);
 831   } else if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
 832               Arch == Triple::arm || Arch == Triple::thumb) &&
 833              (TT.isOSWindows() && TT.getObjectFormat() == Triple::COFF)) {
 834     Env = IsCOFF;
 835     InitCOFFMCObjectFileInfo(TT);
 836   } else {
 837     Env = IsELF;
 838     InitELFMCObjectFileInfo(TT);
 839   }
 840 }
 841
 842 const MCSection *MCObjectFileInfo::getDwarfTypesSection(uint64_t Hash) const {
 843   return Ctx->getELFSection(".debug_types", ELF::SHT_PROGBITS, ELF::SHF_GROUP,
 844                             SectionKind::getMetadata(), 0, utostr(Hash));
 845 }
 846
 847 const MCSection *
 848 MCObjectFileInfo::getDwarfTypesDWOSection(uint64_t Hash) const {
 849   return Ctx->getELFSection(".debug_types.dwo", ELF::SHT_PROGBITS,
 850                             ELF::SHF_GROUP, SectionKind::getMetadata(), 0,
 851                             utostr(Hash));
 852 }
 853
 854 void MCObjectFileInfo::InitEHFrameSection() {
 855   if (Env == IsMachO)
 856     EHFrameSection =
 857       Ctx->getMachOSection("__TEXT", "__eh_frame",
 858                            MachO::S_COALESCED |
 859                            MachO::S_ATTR_NO_TOC |
 860                            MachO::S_ATTR_STRIP_STATIC_SYMS |
 861                            MachO::S_ATTR_LIVE_SUPPORT,
 862                            SectionKind::getReadOnly());
 863   else if (Env == IsELF)
 864     EHFrameSection =
 865       Ctx->getELFSection(".eh_frame", EHSectionType,
 866                          EHSectionFlags,
 867                          SectionKind::getDataRel());
 868   else
 869     EHFrameSection =
 870       Ctx->getCOFFSection(".eh_frame",
 871                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 872                           COFF::IMAGE_SCN_MEM_READ |
 873                           COFF::IMAGE_SCN_MEM_WRITE,
 874                           SectionKind::getDataRel());
 875 }