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 #include "llvm/Support/COFF.h"
  20
  21 using namespace llvm;
  22
  23 static bool useCompactUnwind(const Triple &T) {
  24   // Only on darwin.
  25   if (!T.isOSDarwin())
  26     return false;
  27
  28   // aarch64 always has it.
  29   if (T.getArch() == Triple::aarch64)
  30     return true;
  31
  32   // armv7k always has it.
  33   if (T.isWatchOS())
  34     return true;
  35
  36   // Use it on newer version of OS X.
  37   if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6))
  38     return true;
  39
  40   // And the iOS simulator.
  41   if (T.isiOS() &&
  42       (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86))
  43     return true;
  44
  45   return false;
  46 }
  47
  48 void MCObjectFileInfo::initMachOMCObjectFileInfo(Triple T) {
  49   // MachO
  50   SupportsWeakOmittedEHFrame = false;
  51
  52   EHFrameSection = Ctx->getMachOSection(
  53       "__TEXT", "__eh_frame",
  54       MachO::S_COALESCED | MachO::S_ATTR_NO_TOC |
  55           MachO::S_ATTR_STRIP_STATIC_SYMS | MachO::S_ATTR_LIVE_SUPPORT,
  56       SectionKind::getReadOnly());
  57
  58   if (T.isOSDarwin() && T.getArch() == Triple::aarch64)
  59     SupportsCompactUnwindWithoutEHFrame = true;
  60
  61   if (T.isWatchOS())
  62     OmitDwarfIfHaveCompactUnwind = true;
  63
  64   PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel
  65     | dwarf::DW_EH_PE_sdata4;
  66   LSDAEncoding = FDECFIEncoding = dwarf::DW_EH_PE_pcrel;
  67   TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
  68     dwarf::DW_EH_PE_sdata4;
  69
  70   // .comm doesn't support alignment before Leopard.
  71   if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
  72     CommDirectiveSupportsAlignment = false;
  73
  74   TextSection // .text
  75     = Ctx->getMachOSection("__TEXT", "__text",
  76                            MachO::S_ATTR_PURE_INSTRUCTIONS,
  77                            SectionKind::getText());
  78   DataSection // .data
  79     = Ctx->getMachOSection("__DATA", "__data", 0,
  80                            SectionKind::getDataRel());
  81
  82   // BSSSection might not be expected initialized on msvc.
  83   BSSSection = nullptr;
  84
  85   TLSDataSection // .tdata
  86     = Ctx->getMachOSection("__DATA", "__thread_data",
  87                            MachO::S_THREAD_LOCAL_REGULAR,
  88                            SectionKind::getDataRel());
  89   TLSBSSSection // .tbss
  90     = Ctx->getMachOSection("__DATA", "__thread_bss",
  91                            MachO::S_THREAD_LOCAL_ZEROFILL,
  92                            SectionKind::getThreadBSS());
  93
  94   // TODO: Verify datarel below.
  95   TLSTLVSection // .tlv
  96     = Ctx->getMachOSection("__DATA", "__thread_vars",
  97                            MachO::S_THREAD_LOCAL_VARIABLES,
  98                            SectionKind::getDataRel());
  99
 100   TLSThreadInitSection
 101     = Ctx->getMachOSection("__DATA", "__thread_init",
 102                           MachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
 103                           SectionKind::getDataRel());
 104
 105   CStringSection // .cstring
 106     = Ctx->getMachOSection("__TEXT", "__cstring",
 107                            MachO::S_CSTRING_LITERALS,
 108                            SectionKind::getMergeable1ByteCString());
 109   UStringSection
 110     = Ctx->getMachOSection("__TEXT","__ustring", 0,
 111                            SectionKind::getMergeable2ByteCString());
 112   FourByteConstantSection // .literal4
 113     = Ctx->getMachOSection("__TEXT", "__literal4",
 114                            MachO::S_4BYTE_LITERALS,
 115                            SectionKind::getMergeableConst4());
 116   EightByteConstantSection // .literal8
 117     = Ctx->getMachOSection("__TEXT", "__literal8",
 118                            MachO::S_8BYTE_LITERALS,
 119                            SectionKind::getMergeableConst8());
 120
 121   SixteenByteConstantSection // .literal16
 122       = Ctx->getMachOSection("__TEXT", "__literal16",
 123                              MachO::S_16BYTE_LITERALS,
 124                              SectionKind::getMergeableConst16());
 125
 126   ReadOnlySection  // .const
 127     = Ctx->getMachOSection("__TEXT", "__const", 0,
 128                            SectionKind::getReadOnly());
 129
 130   // If the target is not powerpc, map the coal sections to the non-coal
 131   // sections.
 132   //
 133   // "__TEXT/__textcoal_nt" => section "__TEXT/__text"
 134   // "__TEXT/__const_coal"  => section "__TEXT/__const"
 135   // "__DATA/__datacoal_nt" => section "__DATA/__data"
 136   Triple::ArchType ArchTy = T.getArch();
 137
 138   if (ArchTy == Triple::ppc || ArchTy == Triple::ppc64) {
 139     TextCoalSection
 140       = Ctx->getMachOSection("__TEXT", "__textcoal_nt",
 141                              MachO::S_COALESCED |
 142                              MachO::S_ATTR_PURE_INSTRUCTIONS,
 143                              SectionKind::getText());
 144     ConstTextCoalSection
 145       = Ctx->getMachOSection("__TEXT", "__const_coal",
 146                              MachO::S_COALESCED,
 147                              SectionKind::getReadOnly());
 148     DataCoalSection
 149       = Ctx->getMachOSection("__DATA","__datacoal_nt",
 150                              MachO::S_COALESCED,
 151                              SectionKind::getDataRel());
 152   } else {
 153     TextCoalSection = TextSection;
 154     ConstTextCoalSection = ReadOnlySection;
 155     DataCoalSection = DataSection;
 156   }
 157
 158   ConstDataSection  // .const_data
 159     = Ctx->getMachOSection("__DATA", "__const", 0,
 160                            SectionKind::getReadOnlyWithRel());
 161   DataCommonSection
 162     = Ctx->getMachOSection("__DATA","__common",
 163                            MachO::S_ZEROFILL,
 164                            SectionKind::getBSS());
 165   DataBSSSection
 166     = Ctx->getMachOSection("__DATA","__bss", MachO::S_ZEROFILL,
 167                            SectionKind::getBSS());
 168
 169
 170   LazySymbolPointerSection
 171     = Ctx->getMachOSection("__DATA", "__la_symbol_ptr",
 172                            MachO::S_LAZY_SYMBOL_POINTERS,
 173                            SectionKind::getMetadata());
 174   NonLazySymbolPointerSection
 175     = Ctx->getMachOSection("__DATA", "__nl_symbol_ptr",
 176                            MachO::S_NON_LAZY_SYMBOL_POINTERS,
 177                            SectionKind::getMetadata());
 178
 179   if (RelocM == Reloc::Static) {
 180     StaticCtorSection
 181       = Ctx->getMachOSection("__TEXT", "__constructor", 0,
 182                              SectionKind::getDataRel());
 183     StaticDtorSection
 184       = Ctx->getMachOSection("__TEXT", "__destructor", 0,
 185                              SectionKind::getDataRel());
 186   } else {
 187     StaticCtorSection
 188       = Ctx->getMachOSection("__DATA", "__mod_init_func",
 189                              MachO::S_MOD_INIT_FUNC_POINTERS,
 190                              SectionKind::getDataRel());
 191     StaticDtorSection
 192       = Ctx->getMachOSection("__DATA", "__mod_term_func",
 193                              MachO::S_MOD_TERM_FUNC_POINTERS,
 194                              SectionKind::getDataRel());
 195   }
 196
 197   // Exception Handling.
 198   LSDASection = Ctx->getMachOSection("__TEXT", "__gcc_except_tab", 0,
 199                                      SectionKind::getReadOnlyWithRel());
 200
 201   COFFDebugSymbolsSection = nullptr;
 202
 203   if (useCompactUnwind(T)) {
 204     CompactUnwindSection =
 205         Ctx->getMachOSection("__LD", "__compact_unwind", MachO::S_ATTR_DEBUG,
 206                              SectionKind::getReadOnly());
 207
 208     if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86)
 209       CompactUnwindDwarfEHFrameOnly = 0x04000000;  // UNWIND_X86_64_MODE_DWARF
 210     else if (T.getArch() == Triple::aarch64)
 211       CompactUnwindDwarfEHFrameOnly = 0x03000000;  // UNWIND_ARM64_MODE_DWARF
 212     else if (T.getArch() == Triple::arm || T.getArch() == Triple::thumb)
 213       CompactUnwindDwarfEHFrameOnly = 0x04000000;  // UNWIND_ARM_MODE_DWARF
 214   }
 215
 216   // Debug Information.
 217   DwarfAccelNamesSection =
 218       Ctx->getMachOSection("__DWARF", "__apple_names", MachO::S_ATTR_DEBUG,
 219                            SectionKind::getMetadata(), "names_begin");
 220   DwarfAccelObjCSection =
 221       Ctx->getMachOSection("__DWARF", "__apple_objc", MachO::S_ATTR_DEBUG,
 222                            SectionKind::getMetadata(), "objc_begin");
 223   // 16 character section limit...
 224   DwarfAccelNamespaceSection =
 225       Ctx->getMachOSection("__DWARF", "__apple_namespac", MachO::S_ATTR_DEBUG,
 226                            SectionKind::getMetadata(), "namespac_begin");
 227   DwarfAccelTypesSection =
 228       Ctx->getMachOSection("__DWARF", "__apple_types", MachO::S_ATTR_DEBUG,
 229                            SectionKind::getMetadata(), "types_begin");
 230
 231   DwarfAbbrevSection =
 232       Ctx->getMachOSection("__DWARF", "__debug_abbrev", MachO::S_ATTR_DEBUG,
 233                            SectionKind::getMetadata(), "section_abbrev");
 234   DwarfInfoSection =
 235       Ctx->getMachOSection("__DWARF", "__debug_info", MachO::S_ATTR_DEBUG,
 236                            SectionKind::getMetadata(), "section_info");
 237   DwarfLineSection =
 238       Ctx->getMachOSection("__DWARF", "__debug_line", MachO::S_ATTR_DEBUG,
 239                            SectionKind::getMetadata(), "section_line");
 240   DwarfFrameSection =
 241       Ctx->getMachOSection("__DWARF", "__debug_frame", MachO::S_ATTR_DEBUG,
 242                            SectionKind::getMetadata());
 243   DwarfPubNamesSection =
 244       Ctx->getMachOSection("__DWARF", "__debug_pubnames", MachO::S_ATTR_DEBUG,
 245                            SectionKind::getMetadata());
 246   DwarfPubTypesSection =
 247       Ctx->getMachOSection("__DWARF", "__debug_pubtypes", MachO::S_ATTR_DEBUG,
 248                            SectionKind::getMetadata());
 249   DwarfGnuPubNamesSection =
 250       Ctx->getMachOSection("__DWARF", "__debug_gnu_pubn", MachO::S_ATTR_DEBUG,
 251                            SectionKind::getMetadata());
 252   DwarfGnuPubTypesSection =
 253       Ctx->getMachOSection("__DWARF", "__debug_gnu_pubt", MachO::S_ATTR_DEBUG,
 254                            SectionKind::getMetadata());
 255   DwarfStrSection =
 256       Ctx->getMachOSection("__DWARF", "__debug_str", MachO::S_ATTR_DEBUG,
 257                            SectionKind::getMetadata(), "info_string");
 258   DwarfLocSection =
 259       Ctx->getMachOSection("__DWARF", "__debug_loc", MachO::S_ATTR_DEBUG,
 260                            SectionKind::getMetadata(), "section_debug_loc");
 261   DwarfARangesSection =
 262       Ctx->getMachOSection("__DWARF", "__debug_aranges", MachO::S_ATTR_DEBUG,
 263                            SectionKind::getMetadata());
 264   DwarfRangesSection =
 265       Ctx->getMachOSection("__DWARF", "__debug_ranges", MachO::S_ATTR_DEBUG,
 266                            SectionKind::getMetadata(), "debug_range");
 267   DwarfDebugInlineSection =
 268       Ctx->getMachOSection("__DWARF", "__debug_inlined", MachO::S_ATTR_DEBUG,
 269                            SectionKind::getMetadata());
 270   StackMapSection = Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps",
 271                                          0, SectionKind::getMetadata());
 272
 273   FaultMapSection = Ctx->getMachOSection("__LLVM_FAULTMAPS", "__llvm_faultmaps",
 274                                          0, SectionKind::getMetadata());
 275
 276   TLSExtraDataSection = TLSTLVSection;
 277 }
 278
 279 void MCObjectFileInfo::initELFMCObjectFileInfo(Triple T) {
 280   switch (T.getArch()) {
 281   case Triple::mips:
 282   case Triple::mipsel:
 283     FDECFIEncoding = dwarf::DW_EH_PE_sdata4;
 284     break;
 285   case Triple::mips64:
 286   case Triple::mips64el:
 287     FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
 288     break;
 289   case Triple::x86_64:
 290     FDECFIEncoding = dwarf::DW_EH_PE_pcrel |
 291                      ((CMModel == CodeModel::Large) ? dwarf::DW_EH_PE_sdata8
 292                                                     : dwarf::DW_EH_PE_sdata4);
 293     break;
 294   default:
 295     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 296     break;
 297   }
 298
 299   switch (T.getArch()) {
 300   case Triple::arm:
 301   case Triple::armeb:
 302   case Triple::thumb:
 303   case Triple::thumbeb:
 304     if (Ctx->getAsmInfo()->getExceptionHandlingType() == ExceptionHandling::ARM)
 305       break;
 306     // Fallthrough if not using EHABI
 307   case Triple::ppc:
 308   case Triple::x86:
 309     PersonalityEncoding = (RelocM == Reloc::PIC_)
 310      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 311      : dwarf::DW_EH_PE_absptr;
 312     LSDAEncoding = (RelocM == Reloc::PIC_)
 313       ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 314       : dwarf::DW_EH_PE_absptr;
 315     TTypeEncoding = (RelocM == Reloc::PIC_)
 316      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 317      : dwarf::DW_EH_PE_absptr;
 318     break;
 319   case Triple::x86_64:
 320     if (RelocM == Reloc::PIC_) {
 321       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 322         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 323          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 324       LSDAEncoding = dwarf::DW_EH_PE_pcrel |
 325         (CMModel == CodeModel::Small
 326          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 327       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 328         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 329          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 330     } else {
 331       PersonalityEncoding =
 332         (CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 333         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 334       LSDAEncoding = (CMModel == CodeModel::Small)
 335         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 336       TTypeEncoding = (CMModel == CodeModel::Small)
 337         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 338     }
 339     break;
 340   case Triple::aarch64:
 341   case Triple::aarch64_be:
 342     // The small model guarantees static code/data size < 4GB, but not where it
 343     // will be in memory. Most of these could end up >2GB away so even a signed
 344     // pc-relative 32-bit address is insufficient, theoretically.
 345     if (RelocM == Reloc::PIC_) {
 346       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 347         dwarf::DW_EH_PE_sdata8;
 348       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
 349       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 350         dwarf::DW_EH_PE_sdata8;
 351     } else {
 352       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 353       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 354       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 355     }
 356     break;
 357   case Triple::mips:
 358   case Triple::mipsel:
 359   case Triple::mips64:
 360   case Triple::mips64el:
 361     // MIPS uses indirect pointer to refer personality functions and types, so
 362     // that the eh_frame section can be read-only. DW.ref.personality will be
 363     // generated for relocation.
 364     PersonalityEncoding = dwarf::DW_EH_PE_indirect;
 365     // FIXME: The N64 ABI probably ought to use DW_EH_PE_sdata8 but we can't
 366     //        identify N64 from just a triple.
 367     TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 368                     dwarf::DW_EH_PE_sdata4;
 369     // We don't support PC-relative LSDA references in GAS so we use the default
 370     // DW_EH_PE_absptr for those.
 371     break;
 372   case Triple::ppc64:
 373   case Triple::ppc64le:
 374     PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 375       dwarf::DW_EH_PE_udata8;
 376     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8;
 377     TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 378       dwarf::DW_EH_PE_udata8;
 379     break;
 380   case Triple::sparcel:
 381   case Triple::sparc:
 382     if (RelocM == Reloc::PIC_) {
 383       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 384       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 385         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       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 390       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 391       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 392     }
 393     break;
 394   case Triple::sparcv9:
 395     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 396     if (RelocM == Reloc::PIC_) {
 397       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 398         dwarf::DW_EH_PE_sdata4;
 399       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 400         dwarf::DW_EH_PE_sdata4;
 401     } else {
 402       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 403       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 404     }
 405     break;
 406   case Triple::systemz:
 407     // All currently-defined code models guarantee that 4-byte PC-relative
 408     // values will be in range.
 409     if (RelocM == Reloc::PIC_) {
 410       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 411         dwarf::DW_EH_PE_sdata4;
 412       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 413       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 414         dwarf::DW_EH_PE_sdata4;
 415     } else {
 416       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 417       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 418       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 419     }
 420     break;
 421   default:
 422     break;
 423   }
 424
 425   unsigned EHSectionType = T.getArch() == Triple::x86_64
 426                                ? ELF::SHT_X86_64_UNWIND
 427                                : ELF::SHT_PROGBITS;
 428
 429   // Solaris requires different flags for .eh_frame to seemingly every other
 430   // platform.
 431   unsigned EHSectionFlags = ELF::SHF_ALLOC;
 432   if (T.isOSSolaris() && T.getArch() != Triple::x86_64)
 433     EHSectionFlags |= ELF::SHF_WRITE;
 434
 435   // ELF
 436   BSSSection = Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
 437                                   ELF::SHF_WRITE | ELF::SHF_ALLOC);
 438
 439   TextSection = Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
 440                                    ELF::SHF_EXECINSTR | ELF::SHF_ALLOC);
 441
 442   DataSection = Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
 443                                    ELF::SHF_WRITE | ELF::SHF_ALLOC);
 444
 445   ReadOnlySection =
 446       Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
 447
 448   TLSDataSection =
 449       Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
 450                          ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
 451
 452   TLSBSSSection = Ctx->getELFSection(
 453       ".tbss", ELF::SHT_NOBITS, ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
 454
 455   DataRelSection = Ctx->getELFSection(".data.rel", ELF::SHT_PROGBITS,
 456                                       ELF::SHF_ALLOC | ELF::SHF_WRITE);
 457
 458   DataRelLocalSection = Ctx->getELFSection(".data.rel.local", ELF::SHT_PROGBITS,
 459                                            ELF::SHF_ALLOC | ELF::SHF_WRITE);
 460
 461   DataRelROSection = Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
 462                                         ELF::SHF_ALLOC | ELF::SHF_WRITE);
 463
 464   DataRelROLocalSection = Ctx->getELFSection(
 465       ".data.rel.ro.local", ELF::SHT_PROGBITS, ELF::SHF_ALLOC | ELF::SHF_WRITE);
 466
 467   MergeableConst4Section =
 468       Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
 469                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 4, "");
 470
 471   MergeableConst8Section =
 472       Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
 473                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 8, "");
 474
 475   MergeableConst16Section =
 476       Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
 477                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 16, "");
 478
 479   StaticCtorSection = Ctx->getELFSection(".ctors", ELF::SHT_PROGBITS,
 480                                          ELF::SHF_ALLOC | ELF::SHF_WRITE);
 481
 482   StaticDtorSection = Ctx->getELFSection(".dtors", ELF::SHT_PROGBITS,
 483                                          ELF::SHF_ALLOC | ELF::SHF_WRITE);
 484
 485   // Exception Handling Sections.
 486
 487   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
 488   // it contains relocatable pointers.  In PIC mode, this is probably a big
 489   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
 490   // adjusted or this should be a data section.
 491   LSDASection = Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
 492                                    ELF::SHF_ALLOC);
 493
 494   COFFDebugSymbolsSection = nullptr;
 495
 496   // Debug Info Sections.
 497   DwarfAbbrevSection = Ctx->getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0,
 498                                           "section_abbrev");
 499   DwarfInfoSection =
 500       Ctx->getELFSection(".debug_info", ELF::SHT_PROGBITS, 0, "section_info");
 501   DwarfLineSection = Ctx->getELFSection(".debug_line", ELF::SHT_PROGBITS, 0);
 502   DwarfFrameSection = Ctx->getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0);
 503   DwarfPubNamesSection =
 504       Ctx->getELFSection(".debug_pubnames", ELF::SHT_PROGBITS, 0);
 505   DwarfPubTypesSection =
 506       Ctx->getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0);
 507   DwarfGnuPubNamesSection =
 508       Ctx->getELFSection(".debug_gnu_pubnames", ELF::SHT_PROGBITS, 0);
 509   DwarfGnuPubTypesSection =
 510       Ctx->getELFSection(".debug_gnu_pubtypes", ELF::SHT_PROGBITS, 0);
 511   DwarfStrSection =
 512       Ctx->getELFSection(".debug_str", ELF::SHT_PROGBITS,
 513                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
 514   DwarfLocSection = Ctx->getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0);
 515   DwarfARangesSection =
 516       Ctx->getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0);
 517   DwarfRangesSection =
 518       Ctx->getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0, "debug_range");
 519
 520   // DWARF5 Experimental Debug Info
 521
 522   // Accelerator Tables
 523   DwarfAccelNamesSection =
 524       Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0, "names_begin");
 525   DwarfAccelObjCSection =
 526       Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0, "objc_begin");
 527   DwarfAccelNamespaceSection = Ctx->getELFSection(
 528       ".apple_namespaces", ELF::SHT_PROGBITS, 0, "namespac_begin");
 529   DwarfAccelTypesSection =
 530       Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0, "types_begin");
 531
 532   // Fission Sections
 533   DwarfInfoDWOSection =
 534       Ctx->getELFSection(".debug_info.dwo", ELF::SHT_PROGBITS, 0);
 535   DwarfTypesDWOSection =
 536       Ctx->getELFSection(".debug_types.dwo", ELF::SHT_PROGBITS, 0);
 537   DwarfAbbrevDWOSection =
 538       Ctx->getELFSection(".debug_abbrev.dwo", ELF::SHT_PROGBITS, 0);
 539   DwarfStrDWOSection =
 540       Ctx->getELFSection(".debug_str.dwo", ELF::SHT_PROGBITS,
 541                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
 542   DwarfLineDWOSection =
 543       Ctx->getELFSection(".debug_line.dwo", ELF::SHT_PROGBITS, 0);
 544   DwarfLocDWOSection =
 545       Ctx->getELFSection(".debug_loc.dwo", ELF::SHT_PROGBITS, 0, "skel_loc");
 546   DwarfStrOffDWOSection =
 547       Ctx->getELFSection(".debug_str_offsets.dwo", ELF::SHT_PROGBITS, 0);
 548   DwarfAddrSection =
 549       Ctx->getELFSection(".debug_addr", ELF::SHT_PROGBITS, 0, "addr_sec");
 550
 551   StackMapSection =
 552       Ctx->getELFSection(".llvm_stackmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
 553
 554   FaultMapSection =
 555       Ctx->getELFSection(".llvm_faultmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
 556
 557   EHFrameSection =
 558       Ctx->getELFSection(".eh_frame", EHSectionType, EHSectionFlags);
 559 }
 560
 561 void MCObjectFileInfo::initCOFFMCObjectFileInfo(Triple T) {
 562   EHFrameSection = Ctx->getCOFFSection(
 563       ".eh_frame", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 564                        COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
 565       SectionKind::getDataRel());
 566
 567   bool IsWoA = T.getArch() == Triple::arm || T.getArch() == Triple::thumb;
 568
 569   CommDirectiveSupportsAlignment = true;
 570
 571   // COFF
 572   BSSSection = Ctx->getCOFFSection(
 573       ".bss", COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
 574                   COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
 575       SectionKind::getBSS());
 576   TextSection = Ctx->getCOFFSection(
 577       ".text",
 578       (IsWoA ? COFF::IMAGE_SCN_MEM_16BIT : (COFF::SectionCharacteristics)0) |
 579           COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE |
 580           COFF::IMAGE_SCN_MEM_READ,
 581       SectionKind::getText());
 582   DataSection = Ctx->getCOFFSection(
 583       ".data", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
 584                    COFF::IMAGE_SCN_MEM_WRITE,
 585       SectionKind::getDataRel());
 586   ReadOnlySection = Ctx->getCOFFSection(
 587       ".rdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
 588       SectionKind::getReadOnly());
 589
 590   if (T.isKnownWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) {
 591     StaticCtorSection =
 592         Ctx->getCOFFSection(".CRT$XCU", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 593                                             COFF::IMAGE_SCN_MEM_READ,
 594                             SectionKind::getReadOnly());
 595     StaticDtorSection =
 596         Ctx->getCOFFSection(".CRT$XTX", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 597                                             COFF::IMAGE_SCN_MEM_READ,
 598                             SectionKind::getReadOnly());
 599   } else {
 600     StaticCtorSection = Ctx->getCOFFSection(
 601         ".ctors", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 602                       COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
 603         SectionKind::getDataRel());
 604     StaticDtorSection = Ctx->getCOFFSection(
 605         ".dtors", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 606                       COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
 607         SectionKind::getDataRel());
 608   }
 609
 610   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
 611   // though it contains relocatable pointers.  In PIC mode, this is probably a
 612   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
 613   // adjusted or this should be a data section.
 614   assert(T.isOSWindows() && "Windows is the only supported COFF target");
 615   if (T.getArch() == Triple::x86_64) {
 616     // On Windows 64 with SEH, the LSDA is emitted into the .xdata section
 617     LSDASection = nullptr;
 618   } else {
 619     LSDASection = Ctx->getCOFFSection(".gcc_except_table",
 620                                       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 621                                           COFF::IMAGE_SCN_MEM_READ,
 622                                       SectionKind::getReadOnly());
 623   }
 624
 625   // Debug info.
 626   COFFDebugSymbolsSection =
 627       Ctx->getCOFFSection(".debug$S", COFF::IMAGE_SCN_MEM_DISCARDABLE |
 628                                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 629                                           COFF::IMAGE_SCN_MEM_READ,
 630                           SectionKind::getMetadata());
 631
 632   DwarfAbbrevSection = Ctx->getCOFFSection(
 633       ".debug_abbrev",
 634       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 635           COFF::IMAGE_SCN_MEM_READ,
 636       SectionKind::getMetadata(), "section_abbrev");
 637   DwarfInfoSection = Ctx->getCOFFSection(
 638       ".debug_info",
 639       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 640           COFF::IMAGE_SCN_MEM_READ,
 641       SectionKind::getMetadata(), "section_info");
 642   DwarfLineSection = Ctx->getCOFFSection(
 643       ".debug_line",
 644       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 645           COFF::IMAGE_SCN_MEM_READ,
 646       SectionKind::getMetadata(), "section_line");
 647
 648   DwarfFrameSection = Ctx->getCOFFSection(
 649       ".debug_frame",
 650       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 651           COFF::IMAGE_SCN_MEM_READ,
 652       SectionKind::getMetadata());
 653   DwarfPubNamesSection = Ctx->getCOFFSection(
 654       ".debug_pubnames",
 655       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 656           COFF::IMAGE_SCN_MEM_READ,
 657       SectionKind::getMetadata());
 658   DwarfPubTypesSection = Ctx->getCOFFSection(
 659       ".debug_pubtypes",
 660       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 661           COFF::IMAGE_SCN_MEM_READ,
 662       SectionKind::getMetadata());
 663   DwarfGnuPubNamesSection = Ctx->getCOFFSection(
 664       ".debug_gnu_pubnames",
 665       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 666           COFF::IMAGE_SCN_MEM_READ,
 667       SectionKind::getMetadata());
 668   DwarfGnuPubTypesSection = Ctx->getCOFFSection(
 669       ".debug_gnu_pubtypes",
 670       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 671           COFF::IMAGE_SCN_MEM_READ,
 672       SectionKind::getMetadata());
 673   DwarfStrSection = Ctx->getCOFFSection(
 674       ".debug_str",
 675       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 676           COFF::IMAGE_SCN_MEM_READ,
 677       SectionKind::getMetadata(), "info_string");
 678   DwarfLocSection = Ctx->getCOFFSection(
 679       ".debug_loc",
 680       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 681           COFF::IMAGE_SCN_MEM_READ,
 682       SectionKind::getMetadata(), "section_debug_loc");
 683   DwarfARangesSection = Ctx->getCOFFSection(
 684       ".debug_aranges",
 685       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 686           COFF::IMAGE_SCN_MEM_READ,
 687       SectionKind::getMetadata());
 688   DwarfRangesSection = Ctx->getCOFFSection(
 689       ".debug_ranges",
 690       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 691           COFF::IMAGE_SCN_MEM_READ,
 692       SectionKind::getMetadata(), "debug_range");
 693   DwarfInfoDWOSection = Ctx->getCOFFSection(
 694       ".debug_info.dwo",
 695       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 696           COFF::IMAGE_SCN_MEM_READ,
 697       SectionKind::getMetadata(), "section_info_dwo");
 698   DwarfTypesDWOSection = Ctx->getCOFFSection(
 699       ".debug_types.dwo",
 700       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 701           COFF::IMAGE_SCN_MEM_READ,
 702       SectionKind::getMetadata(), "section_types_dwo");
 703   DwarfAbbrevDWOSection = Ctx->getCOFFSection(
 704       ".debug_abbrev.dwo",
 705       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 706           COFF::IMAGE_SCN_MEM_READ,
 707       SectionKind::getMetadata(), "section_abbrev_dwo");
 708   DwarfStrDWOSection = Ctx->getCOFFSection(
 709       ".debug_str.dwo",
 710       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 711           COFF::IMAGE_SCN_MEM_READ,
 712       SectionKind::getMetadata(), "skel_string");
 713   DwarfLineDWOSection = Ctx->getCOFFSection(
 714       ".debug_line.dwo",
 715       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 716           COFF::IMAGE_SCN_MEM_READ,
 717       SectionKind::getMetadata());
 718   DwarfLocDWOSection = Ctx->getCOFFSection(
 719       ".debug_loc.dwo",
 720       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 721           COFF::IMAGE_SCN_MEM_READ,
 722       SectionKind::getMetadata(), "skel_loc");
 723   DwarfStrOffDWOSection = Ctx->getCOFFSection(
 724       ".debug_str_offsets.dwo",
 725       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 726           COFF::IMAGE_SCN_MEM_READ,
 727       SectionKind::getMetadata());
 728   DwarfAddrSection = Ctx->getCOFFSection(
 729       ".debug_addr",
 730       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 731           COFF::IMAGE_SCN_MEM_READ,
 732       SectionKind::getMetadata(), "addr_sec");
 733   DwarfAccelNamesSection = Ctx->getCOFFSection(
 734       ".apple_names",
 735       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 736           COFF::IMAGE_SCN_MEM_READ,
 737       SectionKind::getMetadata(), "names_begin");
 738   DwarfAccelNamespaceSection = Ctx->getCOFFSection(
 739       ".apple_namespaces",
 740       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 741           COFF::IMAGE_SCN_MEM_READ,
 742       SectionKind::getMetadata(), "namespac_begin");
 743   DwarfAccelTypesSection = Ctx->getCOFFSection(
 744       ".apple_types",
 745       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 746           COFF::IMAGE_SCN_MEM_READ,
 747       SectionKind::getMetadata(), "types_begin");
 748   DwarfAccelObjCSection = Ctx->getCOFFSection(
 749       ".apple_objc",
 750       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 751           COFF::IMAGE_SCN_MEM_READ,
 752       SectionKind::getMetadata(), "objc_begin");
 753
 754   DrectveSection = Ctx->getCOFFSection(
 755       ".drectve", COFF::IMAGE_SCN_LNK_INFO | COFF::IMAGE_SCN_LNK_REMOVE,
 756       SectionKind::getMetadata());
 757
 758   PDataSection = Ctx->getCOFFSection(
 759       ".pdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
 760       SectionKind::getDataRel());
 761
 762   XDataSection = Ctx->getCOFFSection(
 763       ".xdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
 764       SectionKind::getDataRel());
 765
 766   SXDataSection = Ctx->getCOFFSection(".sxdata", COFF::IMAGE_SCN_LNK_INFO,
 767                                       SectionKind::getMetadata());
 768
 769   TLSDataSection = Ctx->getCOFFSection(
 770       ".tls$", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
 771                    COFF::IMAGE_SCN_MEM_WRITE,
 772       SectionKind::getDataRel());
 773
 774   StackMapSection = Ctx->getCOFFSection(".llvm_stackmaps",
 775                                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 776                                             COFF::IMAGE_SCN_MEM_READ,
 777                                         SectionKind::getReadOnly());
 778 }
 779
 780 void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple,
 781                                             Reloc::Model relocm,
 782                                             CodeModel::Model cm,
 783                                             MCContext &ctx) {
 784   RelocM = relocm;
 785   CMModel = cm;
 786   Ctx = &ctx;
 787
 788   // Common.
 789   CommDirectiveSupportsAlignment = true;
 790   SupportsWeakOmittedEHFrame = true;
 791   SupportsCompactUnwindWithoutEHFrame = false;
 792   OmitDwarfIfHaveCompactUnwind = false;
 793
 794   PersonalityEncoding = LSDAEncoding = FDECFIEncoding = TTypeEncoding =
 795       dwarf::DW_EH_PE_absptr;
 796
 797   CompactUnwindDwarfEHFrameOnly = 0;
 798
 799   EHFrameSection = nullptr;             // Created on demand.
 800   CompactUnwindSection = nullptr;       // Used only by selected targets.
 801   DwarfAccelNamesSection = nullptr;     // Used only by selected targets.
 802   DwarfAccelObjCSection = nullptr;      // Used only by selected targets.
 803   DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
 804   DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
 805
 806   TT = TheTriple;
 807
 808   Triple::ArchType Arch = TT.getArch();
 809   // FIXME: Checking for Arch here to filter out bogus triples such as
 810   // cellspu-apple-darwin. Perhaps we should fix in Triple?
 811   if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
 812        Arch == Triple::arm || Arch == Triple::thumb ||
 813        Arch == Triple::aarch64 ||
 814        Arch == Triple::ppc || Arch == Triple::ppc64 ||
 815        Arch == Triple::UnknownArch) &&
 816       TT.isOSBinFormatMachO()) {
 817     Env = IsMachO;
 818     initMachOMCObjectFileInfo(TT);
 819   } else if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
 820               Arch == Triple::arm || Arch == Triple::thumb) &&
 821              (TT.isOSWindows() && TT.getObjectFormat() == Triple::COFF)) {
 822     Env = IsCOFF;
 823     initCOFFMCObjectFileInfo(TT);
 824   } else {
 825     Env = IsELF;
 826     initELFMCObjectFileInfo(TT);
 827   }
 828 }
 829
 830 void MCObjectFileInfo::InitMCObjectFileInfo(StringRef TT, Reloc::Model RM,
 831                                             CodeModel::Model CM,
 832                                             MCContext &ctx) {
 833   InitMCObjectFileInfo(Triple(TT), RM, CM, ctx);
 834 }
 835
 836 MCSection *MCObjectFileInfo::getDwarfTypesSection(uint64_t Hash) const {
 837   return Ctx->getELFSection(".debug_types", ELF::SHT_PROGBITS, ELF::SHF_GROUP,
 838                             0, utostr(Hash));
 839 }