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 using namespace llvm;
  21
  22 static bool useCompactUnwind(const Triple &T) {
  23   // Only on darwin.
  24   if (!T.isOSDarwin())
  25     return false;
  26
  27   // aarch64 always has it.
  28   if (T.getArch() == Triple::aarch64)
  29     return true;
  30
  31   // Use it on newer version of OS X.
  32   if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6))
  33     return true;
  34
  35   // And the iOS simulator.
  36   if (T.isiOS() &&
  37       (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86))
  38     return true;
  39
  40   return false;
  41 }
  42
  43 void MCObjectFileInfo::initMachOMCObjectFileInfo(Triple T) {
  44   // MachO
  45   SupportsWeakOmittedEHFrame = false;
  46
  47   if (T.isOSDarwin() && 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::aarch64)
 182       CompactUnwindDwarfEHFrameOnly = 0x03000000;
 183   }
 184
 185   // Debug Information.
 186   DwarfAccelNamesSection =
 187       Ctx->getMachOSection("__DWARF", "__apple_names", MachO::S_ATTR_DEBUG,
 188                            SectionKind::getMetadata(), "names_begin");
 189   DwarfAccelObjCSection =
 190       Ctx->getMachOSection("__DWARF", "__apple_objc", MachO::S_ATTR_DEBUG,
 191                            SectionKind::getMetadata(), "objc_begin");
 192   // 16 character section limit...
 193   DwarfAccelNamespaceSection =
 194       Ctx->getMachOSection("__DWARF", "__apple_namespac", MachO::S_ATTR_DEBUG,
 195                            SectionKind::getMetadata(), "namespac_begin");
 196   DwarfAccelTypesSection =
 197       Ctx->getMachOSection("__DWARF", "__apple_types", MachO::S_ATTR_DEBUG,
 198                            SectionKind::getMetadata(), "types_begin");
 199
 200   DwarfAbbrevSection =
 201       Ctx->getMachOSection("__DWARF", "__debug_abbrev", MachO::S_ATTR_DEBUG,
 202                            SectionKind::getMetadata(), "section_abbrev");
 203   DwarfInfoSection =
 204       Ctx->getMachOSection("__DWARF", "__debug_info", MachO::S_ATTR_DEBUG,
 205                            SectionKind::getMetadata(), "section_info");
 206   DwarfLineSection =
 207       Ctx->getMachOSection("__DWARF", "__debug_line", MachO::S_ATTR_DEBUG,
 208                            SectionKind::getMetadata(), "section_line");
 209   DwarfFrameSection =
 210       Ctx->getMachOSection("__DWARF", "__debug_frame", MachO::S_ATTR_DEBUG,
 211                            SectionKind::getMetadata());
 212   DwarfPubNamesSection =
 213       Ctx->getMachOSection("__DWARF", "__debug_pubnames", MachO::S_ATTR_DEBUG,
 214                            SectionKind::getMetadata());
 215   DwarfPubTypesSection =
 216       Ctx->getMachOSection("__DWARF", "__debug_pubtypes", MachO::S_ATTR_DEBUG,
 217                            SectionKind::getMetadata());
 218   DwarfGnuPubNamesSection =
 219       Ctx->getMachOSection("__DWARF", "__debug_gnu_pubn", MachO::S_ATTR_DEBUG,
 220                            SectionKind::getMetadata());
 221   DwarfGnuPubTypesSection =
 222       Ctx->getMachOSection("__DWARF", "__debug_gnu_pubt", MachO::S_ATTR_DEBUG,
 223                            SectionKind::getMetadata());
 224   DwarfStrSection =
 225       Ctx->getMachOSection("__DWARF", "__debug_str", MachO::S_ATTR_DEBUG,
 226                            SectionKind::getMetadata(), "info_string");
 227   DwarfLocSection =
 228       Ctx->getMachOSection("__DWARF", "__debug_loc", MachO::S_ATTR_DEBUG,
 229                            SectionKind::getMetadata(), "section_debug_loc");
 230   DwarfARangesSection =
 231       Ctx->getMachOSection("__DWARF", "__debug_aranges", MachO::S_ATTR_DEBUG,
 232                            SectionKind::getMetadata());
 233   DwarfRangesSection =
 234       Ctx->getMachOSection("__DWARF", "__debug_ranges", MachO::S_ATTR_DEBUG,
 235                            SectionKind::getMetadata(), "debug_range");
 236   DwarfDebugInlineSection =
 237       Ctx->getMachOSection("__DWARF", "__debug_inlined", MachO::S_ATTR_DEBUG,
 238                            SectionKind::getMetadata());
 239   StackMapSection = Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps",
 240                                          0, SectionKind::getMetadata());
 241
 242   FaultMapSection = Ctx->getMachOSection("__LLVM_FAULTMAPS", "__llvm_faultmaps",
 243                                          0, SectionKind::getMetadata());
 244
 245   TLSExtraDataSection = TLSTLVSection;
 246 }
 247
 248 void MCObjectFileInfo::initELFMCObjectFileInfo(Triple T) {
 249   switch (T.getArch()) {
 250   case Triple::mips:
 251   case Triple::mipsel:
 252     FDECFIEncoding = dwarf::DW_EH_PE_sdata4;
 253     break;
 254   case Triple::mips64:
 255   case Triple::mips64el:
 256     FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
 257     break;
 258   case Triple::x86_64:
 259     FDECFIEncoding = dwarf::DW_EH_PE_pcrel |
 260                      ((CMModel == CodeModel::Large) ? dwarf::DW_EH_PE_sdata8
 261                                                     : dwarf::DW_EH_PE_sdata4);
 262
 263     break;
 264   default:
 265     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 266     break;
 267   }
 268
 269   switch (T.getArch()) {
 270   case Triple::arm:
 271   case Triple::armeb:
 272   case Triple::thumb:
 273   case Triple::thumbeb:
 274     if (Ctx->getAsmInfo()->getExceptionHandlingType() == ExceptionHandling::ARM)
 275       break;
 276     // Fallthrough if not using EHABI
 277   case Triple::ppc:
 278   case Triple::x86:
 279     PersonalityEncoding = (RelocM == Reloc::PIC_)
 280      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 281      : dwarf::DW_EH_PE_absptr;
 282     LSDAEncoding = (RelocM == Reloc::PIC_)
 283       ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 284       : dwarf::DW_EH_PE_absptr;
 285     TTypeEncoding = (RelocM == Reloc::PIC_)
 286      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 287      : dwarf::DW_EH_PE_absptr;
 288     break;
 289   case Triple::x86_64:
 290     if (RelocM == Reloc::PIC_) {
 291       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 292         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 293          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 294       LSDAEncoding = dwarf::DW_EH_PE_pcrel |
 295         (CMModel == CodeModel::Small
 296          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 297       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 298         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 299          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 300     } else {
 301       PersonalityEncoding =
 302         (CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 303         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 304       LSDAEncoding = (CMModel == CodeModel::Small)
 305         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 306       TTypeEncoding = (CMModel == CodeModel::Small)
 307         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 308     }
 309     break;
 310   case Triple::aarch64:
 311   case Triple::aarch64_be:
 312     // The small model guarantees static code/data size < 4GB, but not where it
 313     // will be in memory. Most of these could end up >2GB away so even a signed
 314     // pc-relative 32-bit address is insufficient, theoretically.
 315     if (RelocM == Reloc::PIC_) {
 316       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 317         dwarf::DW_EH_PE_sdata8;
 318       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
 319       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 320         dwarf::DW_EH_PE_sdata8;
 321     } else {
 322       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 323       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 324       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 325     }
 326     break;
 327   case Triple::mips:
 328   case Triple::mipsel:
 329   case Triple::mips64:
 330   case Triple::mips64el:
 331     // MIPS uses indirect pointer to refer personality functions and types, so
 332     // that the eh_frame section can be read-only. DW.ref.personality will be
 333     // generated for relocation.
 334     PersonalityEncoding = dwarf::DW_EH_PE_indirect;
 335     // FIXME: The N64 ABI probably ought to use DW_EH_PE_sdata8 but we can't
 336     //        identify N64 from just a triple.
 337     TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 338                     dwarf::DW_EH_PE_sdata4;
 339     // We don't support PC-relative LSDA references in GAS so we use the default
 340     // DW_EH_PE_absptr for those.
 341     break;
 342   case Triple::ppc64:
 343   case Triple::ppc64le:
 344     PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 345       dwarf::DW_EH_PE_udata8;
 346     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8;
 347     TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 348       dwarf::DW_EH_PE_udata8;
 349     break;
 350   case Triple::sparcel:
 351   case Triple::sparc:
 352     if (RelocM == Reloc::PIC_) {
 353       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 354       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 355         dwarf::DW_EH_PE_sdata4;
 356       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 357         dwarf::DW_EH_PE_sdata4;
 358     } else {
 359       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 360       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 361       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 362     }
 363     break;
 364   case Triple::sparcv9:
 365     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 366     if (RelocM == Reloc::PIC_) {
 367       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 368         dwarf::DW_EH_PE_sdata4;
 369       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 370         dwarf::DW_EH_PE_sdata4;
 371     } else {
 372       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 373       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 374     }
 375     break;
 376   case Triple::systemz:
 377     // All currently-defined code models guarantee that 4-byte PC-relative
 378     // values will be in range.
 379     if (RelocM == Reloc::PIC_) {
 380       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 381         dwarf::DW_EH_PE_sdata4;
 382       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 383       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 384         dwarf::DW_EH_PE_sdata4;
 385     } else {
 386       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 387       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 388       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 389     }
 390     break;
 391   default:
 392     break;
 393   }
 394
 395   // Solaris requires different flags for .eh_frame to seemingly every other
 396   // platform.
 397   EHSectionType = ELF::SHT_PROGBITS;
 398   EHSectionFlags = ELF::SHF_ALLOC;
 399   if (T.isOSSolaris()) {
 400     if (T.getArch() == Triple::x86_64)
 401       EHSectionType = ELF::SHT_X86_64_UNWIND;
 402     else
 403       EHSectionFlags |= ELF::SHF_WRITE;
 404   }
 405
 406   // ELF
 407   BSSSection = Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
 408                                   ELF::SHF_WRITE | ELF::SHF_ALLOC);
 409
 410   TextSection = Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
 411                                    ELF::SHF_EXECINSTR | ELF::SHF_ALLOC);
 412
 413   DataSection = Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
 414                                    ELF::SHF_WRITE | ELF::SHF_ALLOC);
 415
 416   ReadOnlySection =
 417       Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
 418
 419   TLSDataSection =
 420       Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
 421                          ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
 422
 423   TLSBSSSection = Ctx->getELFSection(
 424       ".tbss", ELF::SHT_NOBITS, ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
 425
 426   DataRelSection = Ctx->getELFSection(".data.rel", ELF::SHT_PROGBITS,
 427                                       ELF::SHF_ALLOC | ELF::SHF_WRITE);
 428
 429   DataRelLocalSection = Ctx->getELFSection(".data.rel.local", ELF::SHT_PROGBITS,
 430                                            ELF::SHF_ALLOC | ELF::SHF_WRITE);
 431
 432   DataRelROSection = Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
 433                                         ELF::SHF_ALLOC | ELF::SHF_WRITE);
 434
 435   DataRelROLocalSection = Ctx->getELFSection(
 436       ".data.rel.ro.local", ELF::SHT_PROGBITS, ELF::SHF_ALLOC | ELF::SHF_WRITE);
 437
 438   MergeableConst4Section =
 439       Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
 440                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 4, "");
 441
 442   MergeableConst8Section =
 443       Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
 444                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 8, "");
 445
 446   MergeableConst16Section =
 447       Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
 448                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 16, "");
 449
 450   StaticCtorSection = Ctx->getELFSection(".ctors", ELF::SHT_PROGBITS,
 451                                          ELF::SHF_ALLOC | ELF::SHF_WRITE);
 452
 453   StaticDtorSection = Ctx->getELFSection(".dtors", ELF::SHT_PROGBITS,
 454                                          ELF::SHF_ALLOC | ELF::SHF_WRITE);
 455
 456   // Exception Handling Sections.
 457
 458   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
 459   // it contains relocatable pointers.  In PIC mode, this is probably a big
 460   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
 461   // adjusted or this should be a data section.
 462   LSDASection = Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
 463                                    ELF::SHF_ALLOC);
 464
 465   COFFDebugSymbolsSection = nullptr;
 466
 467   // Debug Info Sections.
 468   DwarfAbbrevSection = Ctx->getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0,
 469                                           "section_abbrev");
 470   DwarfInfoSection =
 471       Ctx->getELFSection(".debug_info", ELF::SHT_PROGBITS, 0, "section_info");
 472   DwarfLineSection = Ctx->getELFSection(".debug_line", ELF::SHT_PROGBITS, 0);
 473   DwarfFrameSection = Ctx->getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0);
 474   DwarfPubNamesSection =
 475       Ctx->getELFSection(".debug_pubnames", ELF::SHT_PROGBITS, 0);
 476   DwarfPubTypesSection =
 477       Ctx->getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0);
 478   DwarfGnuPubNamesSection =
 479       Ctx->getELFSection(".debug_gnu_pubnames", ELF::SHT_PROGBITS, 0);
 480   DwarfGnuPubTypesSection =
 481       Ctx->getELFSection(".debug_gnu_pubtypes", ELF::SHT_PROGBITS, 0);
 482   DwarfStrSection =
 483       Ctx->getELFSection(".debug_str", ELF::SHT_PROGBITS,
 484                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
 485   DwarfLocSection = Ctx->getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0);
 486   DwarfARangesSection =
 487       Ctx->getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0);
 488   DwarfRangesSection =
 489       Ctx->getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0, "debug_range");
 490
 491   // DWARF5 Experimental Debug Info
 492
 493   // Accelerator Tables
 494   DwarfAccelNamesSection =
 495       Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0, "names_begin");
 496   DwarfAccelObjCSection =
 497       Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0, "objc_begin");
 498   DwarfAccelNamespaceSection = Ctx->getELFSection(
 499       ".apple_namespaces", ELF::SHT_PROGBITS, 0, "namespac_begin");
 500   DwarfAccelTypesSection =
 501       Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0, "types_begin");
 502
 503   // Fission Sections
 504   DwarfInfoDWOSection =
 505       Ctx->getELFSection(".debug_info.dwo", ELF::SHT_PROGBITS, 0);
 506   DwarfTypesDWOSection =
 507       Ctx->getELFSection(".debug_types.dwo", ELF::SHT_PROGBITS, 0);
 508   DwarfAbbrevDWOSection =
 509       Ctx->getELFSection(".debug_abbrev.dwo", ELF::SHT_PROGBITS, 0);
 510   DwarfStrDWOSection =
 511       Ctx->getELFSection(".debug_str.dwo", ELF::SHT_PROGBITS,
 512                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
 513   DwarfLineDWOSection =
 514       Ctx->getELFSection(".debug_line.dwo", ELF::SHT_PROGBITS, 0);
 515   DwarfLocDWOSection =
 516       Ctx->getELFSection(".debug_loc.dwo", ELF::SHT_PROGBITS, 0, "skel_loc");
 517   DwarfStrOffDWOSection =
 518       Ctx->getELFSection(".debug_str_offsets.dwo", ELF::SHT_PROGBITS, 0);
 519   DwarfAddrSection =
 520       Ctx->getELFSection(".debug_addr", ELF::SHT_PROGBITS, 0, "addr_sec");
 521
 522   StackMapSection =
 523       Ctx->getELFSection(".llvm_stackmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
 524
 525   FaultMapSection =
 526       Ctx->getELFSection(".llvm_faultmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
 527 }
 528
 529 void MCObjectFileInfo::initCOFFMCObjectFileInfo(Triple T) {
 530   bool IsWoA = T.getArch() == Triple::arm || T.getArch() == Triple::thumb;
 531
 532   CommDirectiveSupportsAlignment = true;
 533
 534   // COFF
 535   BSSSection = Ctx->getCOFFSection(
 536       ".bss", COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
 537                   COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
 538       SectionKind::getBSS());
 539   TextSection = Ctx->getCOFFSection(
 540       ".text",
 541       (IsWoA ? COFF::IMAGE_SCN_MEM_16BIT : (COFF::SectionCharacteristics)0) |
 542           COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE |
 543           COFF::IMAGE_SCN_MEM_READ,
 544       SectionKind::getText());
 545   DataSection = Ctx->getCOFFSection(
 546       ".data", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
 547                    COFF::IMAGE_SCN_MEM_WRITE,
 548       SectionKind::getDataRel());
 549   ReadOnlySection = Ctx->getCOFFSection(
 550       ".rdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
 551       SectionKind::getReadOnly());
 552
 553   if (T.isKnownWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) {
 554     StaticCtorSection =
 555         Ctx->getCOFFSection(".CRT$XCU", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 556                                             COFF::IMAGE_SCN_MEM_READ,
 557                             SectionKind::getReadOnly());
 558     StaticDtorSection =
 559         Ctx->getCOFFSection(".CRT$XTX", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 560                                             COFF::IMAGE_SCN_MEM_READ,
 561                             SectionKind::getReadOnly());
 562   } else {
 563     StaticCtorSection = Ctx->getCOFFSection(
 564         ".ctors", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 565                       COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
 566         SectionKind::getDataRel());
 567     StaticDtorSection = Ctx->getCOFFSection(
 568         ".dtors", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 569                       COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
 570         SectionKind::getDataRel());
 571   }
 572
 573   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
 574   // though it contains relocatable pointers.  In PIC mode, this is probably a
 575   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
 576   // adjusted or this should be a data section.
 577   assert(T.isOSWindows() && "Windows is the only supported COFF target");
 578   if (T.getArch() == Triple::x86_64) {
 579     // On Windows 64 with SEH, the LSDA is emitted into the .xdata section
 580     LSDASection = 0;
 581   } else {
 582     LSDASection = Ctx->getCOFFSection(".gcc_except_table",
 583                                       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 584                                           COFF::IMAGE_SCN_MEM_READ,
 585                                       SectionKind::getReadOnly());
 586   }
 587
 588   // Debug info.
 589   COFFDebugSymbolsSection =
 590       Ctx->getCOFFSection(".debug$S", COFF::IMAGE_SCN_MEM_DISCARDABLE |
 591                                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 592                                           COFF::IMAGE_SCN_MEM_READ,
 593                           SectionKind::getMetadata());
 594
 595   DwarfAbbrevSection = Ctx->getCOFFSection(
 596       ".debug_abbrev",
 597       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 598           COFF::IMAGE_SCN_MEM_READ,
 599       SectionKind::getMetadata(), "section_abbrev");
 600   DwarfInfoSection = Ctx->getCOFFSection(
 601       ".debug_info",
 602       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 603           COFF::IMAGE_SCN_MEM_READ,
 604       SectionKind::getMetadata(), "section_info");
 605   DwarfLineSection = Ctx->getCOFFSection(
 606       ".debug_line",
 607       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 608           COFF::IMAGE_SCN_MEM_READ,
 609       SectionKind::getMetadata(), "section_line");
 610
 611   DwarfFrameSection = Ctx->getCOFFSection(
 612       ".debug_frame",
 613       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 614           COFF::IMAGE_SCN_MEM_READ,
 615       SectionKind::getMetadata());
 616   DwarfPubNamesSection = Ctx->getCOFFSection(
 617       ".debug_pubnames",
 618       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 619           COFF::IMAGE_SCN_MEM_READ,
 620       SectionKind::getMetadata());
 621   DwarfPubTypesSection = Ctx->getCOFFSection(
 622       ".debug_pubtypes",
 623       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 624           COFF::IMAGE_SCN_MEM_READ,
 625       SectionKind::getMetadata());
 626   DwarfGnuPubNamesSection = Ctx->getCOFFSection(
 627       ".debug_gnu_pubnames",
 628       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 629           COFF::IMAGE_SCN_MEM_READ,
 630       SectionKind::getMetadata());
 631   DwarfGnuPubTypesSection = Ctx->getCOFFSection(
 632       ".debug_gnu_pubtypes",
 633       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 634           COFF::IMAGE_SCN_MEM_READ,
 635       SectionKind::getMetadata());
 636   DwarfStrSection = Ctx->getCOFFSection(
 637       ".debug_str",
 638       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 639           COFF::IMAGE_SCN_MEM_READ,
 640       SectionKind::getMetadata(), "info_string");
 641   DwarfLocSection = Ctx->getCOFFSection(
 642       ".debug_loc",
 643       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 644           COFF::IMAGE_SCN_MEM_READ,
 645       SectionKind::getMetadata(), "section_debug_loc");
 646   DwarfARangesSection = Ctx->getCOFFSection(
 647       ".debug_aranges",
 648       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 649           COFF::IMAGE_SCN_MEM_READ,
 650       SectionKind::getMetadata());
 651   DwarfRangesSection = Ctx->getCOFFSection(
 652       ".debug_ranges",
 653       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 654           COFF::IMAGE_SCN_MEM_READ,
 655       SectionKind::getMetadata(), "debug_range");
 656   DwarfInfoDWOSection = Ctx->getCOFFSection(
 657       ".debug_info.dwo",
 658       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 659           COFF::IMAGE_SCN_MEM_READ,
 660       SectionKind::getMetadata(), "section_info_dwo");
 661   DwarfTypesDWOSection = Ctx->getCOFFSection(
 662       ".debug_types.dwo",
 663       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 664           COFF::IMAGE_SCN_MEM_READ,
 665       SectionKind::getMetadata(), "section_types_dwo");
 666   DwarfAbbrevDWOSection = Ctx->getCOFFSection(
 667       ".debug_abbrev.dwo",
 668       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 669           COFF::IMAGE_SCN_MEM_READ,
 670       SectionKind::getMetadata(), "section_abbrev_dwo");
 671   DwarfStrDWOSection = Ctx->getCOFFSection(
 672       ".debug_str.dwo",
 673       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 674           COFF::IMAGE_SCN_MEM_READ,
 675       SectionKind::getMetadata(), "skel_string");
 676   DwarfLineDWOSection = Ctx->getCOFFSection(
 677       ".debug_line.dwo",
 678       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 679           COFF::IMAGE_SCN_MEM_READ,
 680       SectionKind::getMetadata());
 681   DwarfLocDWOSection = Ctx->getCOFFSection(
 682       ".debug_loc.dwo",
 683       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 684           COFF::IMAGE_SCN_MEM_READ,
 685       SectionKind::getMetadata(), "skel_loc");
 686   DwarfStrOffDWOSection = Ctx->getCOFFSection(
 687       ".debug_str_offsets.dwo",
 688       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 689           COFF::IMAGE_SCN_MEM_READ,
 690       SectionKind::getMetadata());
 691   DwarfAddrSection = Ctx->getCOFFSection(
 692       ".debug_addr",
 693       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 694           COFF::IMAGE_SCN_MEM_READ,
 695       SectionKind::getMetadata(), "addr_sec");
 696   DwarfAccelNamesSection = Ctx->getCOFFSection(
 697       ".apple_names",
 698       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 699           COFF::IMAGE_SCN_MEM_READ,
 700       SectionKind::getMetadata(), "names_begin");
 701   DwarfAccelNamespaceSection = Ctx->getCOFFSection(
 702       ".apple_namespaces",
 703       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 704           COFF::IMAGE_SCN_MEM_READ,
 705       SectionKind::getMetadata(), "namespac_begin");
 706   DwarfAccelTypesSection = Ctx->getCOFFSection(
 707       ".apple_types",
 708       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 709           COFF::IMAGE_SCN_MEM_READ,
 710       SectionKind::getMetadata(), "types_begin");
 711   DwarfAccelObjCSection = Ctx->getCOFFSection(
 712       ".apple_objc",
 713       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 714           COFF::IMAGE_SCN_MEM_READ,
 715       SectionKind::getMetadata(), "objc_begin");
 716
 717   DrectveSection = Ctx->getCOFFSection(
 718       ".drectve", COFF::IMAGE_SCN_LNK_INFO | COFF::IMAGE_SCN_LNK_REMOVE,
 719       SectionKind::getMetadata());
 720
 721   PDataSection = Ctx->getCOFFSection(
 722       ".pdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
 723       SectionKind::getDataRel());
 724
 725   XDataSection = Ctx->getCOFFSection(
 726       ".xdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
 727       SectionKind::getDataRel());
 728
 729   SXDataSection = Ctx->getCOFFSection(".sxdata", COFF::IMAGE_SCN_LNK_INFO,
 730                                       SectionKind::getMetadata());
 731
 732   TLSDataSection = Ctx->getCOFFSection(
 733       ".tls$", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
 734                    COFF::IMAGE_SCN_MEM_WRITE,
 735       SectionKind::getDataRel());
 736
 737   StackMapSection = Ctx->getCOFFSection(".llvm_stackmaps",
 738                                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 739                                             COFF::IMAGE_SCN_MEM_READ,
 740                                         SectionKind::getReadOnly());
 741 }
 742
 743 void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple,
 744                                             Reloc::Model relocm,
 745                                             CodeModel::Model cm,
 746                                             MCContext &ctx) {
 747   RelocM = relocm;
 748   CMModel = cm;
 749   Ctx = &ctx;
 750
 751   // Common.
 752   CommDirectiveSupportsAlignment = true;
 753   SupportsWeakOmittedEHFrame = true;
 754   SupportsCompactUnwindWithoutEHFrame = false;
 755
 756   PersonalityEncoding = LSDAEncoding = FDECFIEncoding = TTypeEncoding =
 757       dwarf::DW_EH_PE_absptr;
 758
 759   CompactUnwindDwarfEHFrameOnly = 0;
 760
 761   EHFrameSection = nullptr;             // Created on demand.
 762   CompactUnwindSection = nullptr;       // Used only by selected targets.
 763   DwarfAccelNamesSection = nullptr;     // Used only by selected targets.
 764   DwarfAccelObjCSection = nullptr;      // Used only by selected targets.
 765   DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
 766   DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
 767
 768   TT = TheTriple;
 769
 770   Triple::ArchType Arch = TT.getArch();
 771   // FIXME: Checking for Arch here to filter out bogus triples such as
 772   // cellspu-apple-darwin. Perhaps we should fix in Triple?
 773   if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
 774        Arch == Triple::arm || Arch == Triple::thumb ||
 775        Arch == Triple::aarch64 ||
 776        Arch == Triple::ppc || Arch == Triple::ppc64 ||
 777        Arch == Triple::UnknownArch) &&
 778       TT.isOSBinFormatMachO()) {
 779     Env = IsMachO;
 780     initMachOMCObjectFileInfo(TT);
 781   } else if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
 782               Arch == Triple::arm || Arch == Triple::thumb) &&
 783              (TT.isOSWindows() && TT.getObjectFormat() == Triple::COFF)) {
 784     Env = IsCOFF;
 785     initCOFFMCObjectFileInfo(TT);
 786   } else {
 787     Env = IsELF;
 788     initELFMCObjectFileInfo(TT);
 789   }
 790 }
 791
 792 void MCObjectFileInfo::InitMCObjectFileInfo(StringRef TT, Reloc::Model RM,
 793                                             CodeModel::Model CM,
 794                                             MCContext &ctx) {
 795   InitMCObjectFileInfo(Triple(TT), RM, CM, ctx);
 796 }
 797
 798 MCSection *MCObjectFileInfo::getDwarfTypesSection(uint64_t Hash) const {
 799   return Ctx->getELFSection(".debug_types", ELF::SHT_PROGBITS, ELF::SHF_GROUP,
 800                             0, utostr(Hash));
 801 }
 802
 803 void MCObjectFileInfo::InitEHFrameSection() {
 804   if (Env == IsMachO)
 805     EHFrameSection =
 806       Ctx->getMachOSection("__TEXT", "__eh_frame",
 807                            MachO::S_COALESCED |
 808                            MachO::S_ATTR_NO_TOC |
 809                            MachO::S_ATTR_STRIP_STATIC_SYMS |
 810                            MachO::S_ATTR_LIVE_SUPPORT,
 811                            SectionKind::getReadOnly());
 812   else if (Env == IsELF)
 813     EHFrameSection =
 814         Ctx->getELFSection(".eh_frame", EHSectionType, EHSectionFlags);
 815   else
 816     EHFrameSection =
 817       Ctx->getCOFFSection(".eh_frame",
 818                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 819                           COFF::IMAGE_SCN_MEM_READ |
 820                           COFF::IMAGE_SCN_MEM_WRITE,
 821                           SectionKind::getDataRel());
 822 }