lib/MC/MCObjectFileInfo.cpp

   1 //===-- MObjectFileInfo.cpp - Object File Information ---------------------===//
   2 //
   3 //                     The LLVM Compiler Infrastructure
   4 //
   5 // This file is distributed under the University of Illinois Open Source
   6 // License. See LICENSE.TXT for details.
   7 //
   8 //===----------------------------------------------------------------------===//
   9
  10 #include "llvm/MC/MCObjectFileInfo.h"
  11 #include "llvm/ADT/StringExtras.h"
  12 #include "llvm/ADT/Triple.h"
  13 #include "llvm/MC/MCAsmInfo.h"
  14 #include "llvm/MC/MCContext.h"
  15 #include "llvm/MC/MCSection.h"
  16 #include "llvm/MC/MCSectionCOFF.h"
  17 #include "llvm/MC/MCSectionELF.h"
  18 #include "llvm/MC/MCSectionMachO.h"
  19 using namespace llvm;
  20
  21 static bool useCompactUnwind(const Triple &T) {
  22   // Only on darwin.
  23   if (!T.isOSDarwin())
  24     return false;
  25
  26   // aarch64 always has it.
  27   if (T.getArch() == Triple::aarch64)
  28     return true;
  29
  30   // Use it on newer version of OS X.
  31   if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6))
  32     return true;
  33
  34   // And the iOS simulator.
  35   if (T.isiOS() &&
  36       (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86))
  37     return true;
  38
  39   return false;
  40 }
  41
  42 void MCObjectFileInfo::InitMachOMCObjectFileInfo(Triple T) {
  43   // MachO
  44   SupportsWeakOmittedEHFrame = false;
  45
  46   if (T.isOSDarwin() && T.getArch() == Triple::aarch64)
  47     SupportsCompactUnwindWithoutEHFrame = true;
  48
  49   PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel
  50     | dwarf::DW_EH_PE_sdata4;
  51   LSDAEncoding = FDECFIEncoding = dwarf::DW_EH_PE_pcrel;
  52   TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
  53     dwarf::DW_EH_PE_sdata4;
  54
  55   // .comm doesn't support alignment before Leopard.
  56   if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
  57     CommDirectiveSupportsAlignment = false;
  58
  59   TextSection // .text
  60     = Ctx->getMachOSection("__TEXT", "__text",
  61                            MachO::S_ATTR_PURE_INSTRUCTIONS,
  62                            SectionKind::getText());
  63   DataSection // .data
  64     = Ctx->getMachOSection("__DATA", "__data", 0,
  65                            SectionKind::getDataRel());
  66
  67   // BSSSection might not be expected initialized on msvc.
  68   BSSSection = nullptr;
  69
  70   TLSDataSection // .tdata
  71     = Ctx->getMachOSection("__DATA", "__thread_data",
  72                            MachO::S_THREAD_LOCAL_REGULAR,
  73                            SectionKind::getDataRel());
  74   TLSBSSSection // .tbss
  75     = Ctx->getMachOSection("__DATA", "__thread_bss",
  76                            MachO::S_THREAD_LOCAL_ZEROFILL,
  77                            SectionKind::getThreadBSS());
  78
  79   // TODO: Verify datarel below.
  80   TLSTLVSection // .tlv
  81     = Ctx->getMachOSection("__DATA", "__thread_vars",
  82                            MachO::S_THREAD_LOCAL_VARIABLES,
  83                            SectionKind::getDataRel());
  84
  85   TLSThreadInitSection
  86     = Ctx->getMachOSection("__DATA", "__thread_init",
  87                           MachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
  88                           SectionKind::getDataRel());
  89
  90   CStringSection // .cstring
  91     = Ctx->getMachOSection("__TEXT", "__cstring",
  92                            MachO::S_CSTRING_LITERALS,
  93                            SectionKind::getMergeable1ByteCString());
  94   UStringSection
  95     = Ctx->getMachOSection("__TEXT","__ustring", 0,
  96                            SectionKind::getMergeable2ByteCString());
  97   FourByteConstantSection // .literal4
  98     = Ctx->getMachOSection("__TEXT", "__literal4",
  99                            MachO::S_4BYTE_LITERALS,
 100                            SectionKind::getMergeableConst4());
 101   EightByteConstantSection // .literal8
 102     = Ctx->getMachOSection("__TEXT", "__literal8",
 103                            MachO::S_8BYTE_LITERALS,
 104                            SectionKind::getMergeableConst8());
 105
 106   SixteenByteConstantSection // .literal16
 107       = Ctx->getMachOSection("__TEXT", "__literal16",
 108                              MachO::S_16BYTE_LITERALS,
 109                              SectionKind::getMergeableConst16());
 110
 111   ReadOnlySection  // .const
 112     = Ctx->getMachOSection("__TEXT", "__const", 0,
 113                            SectionKind::getReadOnly());
 114
 115   TextCoalSection
 116     = Ctx->getMachOSection("__TEXT", "__textcoal_nt",
 117                            MachO::S_COALESCED |
 118                            MachO::S_ATTR_PURE_INSTRUCTIONS,
 119                            SectionKind::getText());
 120   ConstTextCoalSection
 121     = Ctx->getMachOSection("__TEXT", "__const_coal",
 122                            MachO::S_COALESCED,
 123                            SectionKind::getReadOnly());
 124   ConstDataSection  // .const_data
 125     = Ctx->getMachOSection("__DATA", "__const", 0,
 126                            SectionKind::getReadOnlyWithRel());
 127   DataCoalSection
 128     = Ctx->getMachOSection("__DATA","__datacoal_nt",
 129                            MachO::S_COALESCED,
 130                            SectionKind::getDataRel());
 131   DataCommonSection
 132     = Ctx->getMachOSection("__DATA","__common",
 133                            MachO::S_ZEROFILL,
 134                            SectionKind::getBSS());
 135   DataBSSSection
 136     = Ctx->getMachOSection("__DATA","__bss", MachO::S_ZEROFILL,
 137                            SectionKind::getBSS());
 138
 139
 140   LazySymbolPointerSection
 141     = Ctx->getMachOSection("__DATA", "__la_symbol_ptr",
 142                            MachO::S_LAZY_SYMBOL_POINTERS,
 143                            SectionKind::getMetadata());
 144   NonLazySymbolPointerSection
 145     = Ctx->getMachOSection("__DATA", "__nl_symbol_ptr",
 146                            MachO::S_NON_LAZY_SYMBOL_POINTERS,
 147                            SectionKind::getMetadata());
 148
 149   if (RelocM == Reloc::Static) {
 150     StaticCtorSection
 151       = Ctx->getMachOSection("__TEXT", "__constructor", 0,
 152                              SectionKind::getDataRel());
 153     StaticDtorSection
 154       = Ctx->getMachOSection("__TEXT", "__destructor", 0,
 155                              SectionKind::getDataRel());
 156   } else {
 157     StaticCtorSection
 158       = Ctx->getMachOSection("__DATA", "__mod_init_func",
 159                              MachO::S_MOD_INIT_FUNC_POINTERS,
 160                              SectionKind::getDataRel());
 161     StaticDtorSection
 162       = Ctx->getMachOSection("__DATA", "__mod_term_func",
 163                              MachO::S_MOD_TERM_FUNC_POINTERS,
 164                              SectionKind::getDataRel());
 165   }
 166
 167   // Exception Handling.
 168   LSDASection = Ctx->getMachOSection("__TEXT", "__gcc_except_tab", 0,
 169                                      SectionKind::getReadOnlyWithRel());
 170
 171   COFFDebugSymbolsSection = nullptr;
 172
 173   if (useCompactUnwind(T)) {
 174     CompactUnwindSection =
 175         Ctx->getMachOSection("__LD", "__compact_unwind", MachO::S_ATTR_DEBUG,
 176                              SectionKind::getReadOnly());
 177
 178     if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86)
 179       CompactUnwindDwarfEHFrameOnly = 0x04000000;
 180     else if (T.getArch() == Triple::aarch64)
 181       CompactUnwindDwarfEHFrameOnly = 0x03000000;
 182   }
 183
 184   // Debug Information.
 185   DwarfAccelNamesSection =
 186     Ctx->getMachOSection("__DWARF", "__apple_names",
 187                          MachO::S_ATTR_DEBUG,
 188                          SectionKind::getMetadata());
 189   DwarfAccelObjCSection =
 190     Ctx->getMachOSection("__DWARF", "__apple_objc",
 191                          MachO::S_ATTR_DEBUG,
 192                          SectionKind::getMetadata());
 193   // 16 character section limit...
 194   DwarfAccelNamespaceSection =
 195     Ctx->getMachOSection("__DWARF", "__apple_namespac",
 196                          MachO::S_ATTR_DEBUG,
 197                          SectionKind::getMetadata());
 198   DwarfAccelTypesSection =
 199     Ctx->getMachOSection("__DWARF", "__apple_types",
 200                          MachO::S_ATTR_DEBUG,
 201                          SectionKind::getMetadata());
 202
 203   DwarfAbbrevSection =
 204     Ctx->getMachOSection("__DWARF", "__debug_abbrev",
 205                          MachO::S_ATTR_DEBUG,
 206                          SectionKind::getMetadata());
 207   DwarfInfoSection =
 208     Ctx->getMachOSection("__DWARF", "__debug_info",
 209                          MachO::S_ATTR_DEBUG,
 210                          SectionKind::getMetadata());
 211   DwarfLineSection =
 212     Ctx->getMachOSection("__DWARF", "__debug_line",
 213                          MachO::S_ATTR_DEBUG,
 214                          SectionKind::getMetadata());
 215   DwarfFrameSection =
 216     Ctx->getMachOSection("__DWARF", "__debug_frame",
 217                          MachO::S_ATTR_DEBUG,
 218                          SectionKind::getMetadata());
 219   DwarfPubNamesSection =
 220     Ctx->getMachOSection("__DWARF", "__debug_pubnames",
 221                          MachO::S_ATTR_DEBUG,
 222                          SectionKind::getMetadata());
 223   DwarfPubTypesSection =
 224     Ctx->getMachOSection("__DWARF", "__debug_pubtypes",
 225                          MachO::S_ATTR_DEBUG,
 226                          SectionKind::getMetadata());
 227   DwarfGnuPubNamesSection =
 228     Ctx->getMachOSection("__DWARF", "__debug_gnu_pubn",
 229                          MachO::S_ATTR_DEBUG,
 230                          SectionKind::getMetadata());
 231   DwarfGnuPubTypesSection =
 232     Ctx->getMachOSection("__DWARF", "__debug_gnu_pubt",
 233                          MachO::S_ATTR_DEBUG,
 234                          SectionKind::getMetadata());
 235   DwarfStrSection =
 236     Ctx->getMachOSection("__DWARF", "__debug_str",
 237                          MachO::S_ATTR_DEBUG,
 238                          SectionKind::getMetadata());
 239   DwarfLocSection =
 240     Ctx->getMachOSection("__DWARF", "__debug_loc",
 241                          MachO::S_ATTR_DEBUG,
 242                          SectionKind::getMetadata());
 243   DwarfARangesSection =
 244     Ctx->getMachOSection("__DWARF", "__debug_aranges",
 245                          MachO::S_ATTR_DEBUG,
 246                          SectionKind::getMetadata());
 247   DwarfRangesSection =
 248     Ctx->getMachOSection("__DWARF", "__debug_ranges",
 249                          MachO::S_ATTR_DEBUG,
 250                          SectionKind::getMetadata());
 251   DwarfMacroInfoSection =
 252     Ctx->getMachOSection("__DWARF", "__debug_macinfo",
 253                          MachO::S_ATTR_DEBUG,
 254                          SectionKind::getMetadata());
 255   DwarfDebugInlineSection =
 256     Ctx->getMachOSection("__DWARF", "__debug_inlined",
 257                          MachO::S_ATTR_DEBUG,
 258                          SectionKind::getMetadata());
 259   StackMapSection =
 260     Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps", 0,
 261                          SectionKind::getMetadata());
 262
 263   TLSExtraDataSection = TLSTLVSection;
 264 }
 265
 266 void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
 267   switch (T.getArch()) {
 268   case Triple::mips:
 269   case Triple::mipsel:
 270     FDECFIEncoding = dwarf::DW_EH_PE_sdata4;
 271     break;
 272   case Triple::mips64:
 273   case Triple::mips64el:
 274     FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
 275     break;
 276   default:
 277     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 278     break;
 279   }
 280
 281   switch (T.getArch()) {
 282   case Triple::arm:
 283   case Triple::armeb:
 284   case Triple::thumb:
 285   case Triple::thumbeb:
 286     if (Ctx->getAsmInfo()->getExceptionHandlingType() == ExceptionHandling::ARM)
 287       break;
 288     // Fallthrough if not using EHABI
 289   case Triple::ppc:
 290   case Triple::x86:
 291     PersonalityEncoding = (RelocM == Reloc::PIC_)
 292      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 293      : dwarf::DW_EH_PE_absptr;
 294     LSDAEncoding = (RelocM == Reloc::PIC_)
 295       ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 296       : dwarf::DW_EH_PE_absptr;
 297     TTypeEncoding = (RelocM == Reloc::PIC_)
 298      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
 299      : dwarf::DW_EH_PE_absptr;
 300     break;
 301   case Triple::x86_64:
 302     if (RelocM == Reloc::PIC_) {
 303       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 304         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 305          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 306       LSDAEncoding = dwarf::DW_EH_PE_pcrel |
 307         (CMModel == CodeModel::Small
 308          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 309       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 310         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 311          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
 312     } else {
 313       PersonalityEncoding =
 314         (CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
 315         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 316       LSDAEncoding = (CMModel == CodeModel::Small)
 317         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 318       TTypeEncoding = (CMModel == CodeModel::Small)
 319         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
 320     }
 321     break;
 322   case Triple::aarch64:
 323   case Triple::aarch64_be:
 324     // The small model guarantees static code/data size < 4GB, but not where it
 325     // will be in memory. Most of these could end up >2GB away so even a signed
 326     // pc-relative 32-bit address is insufficient, theoretically.
 327     if (RelocM == Reloc::PIC_) {
 328       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 329         dwarf::DW_EH_PE_sdata8;
 330       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
 331       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
 332         dwarf::DW_EH_PE_sdata8;
 333     } else {
 334       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
 335       LSDAEncoding = dwarf::DW_EH_PE_absptr;
 336       TTypeEncoding = dwarf::DW_EH_PE_absptr;
 337     }
 338     break;
 339   case Triple::mips:
 340   case Triple::mipsel:
 341   case Triple::mips64:
 342   case Triple::mips64el:
 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   DwarfTypesDWOSection =
 567     Ctx->getELFSection(".debug_types.dwo", ELF::SHT_PROGBITS, 0,
 568                        SectionKind::getMetadata());
 569   DwarfAbbrevDWOSection =
 570     Ctx->getELFSection(".debug_abbrev.dwo", ELF::SHT_PROGBITS, 0,
 571                        SectionKind::getMetadata());
 572   DwarfStrDWOSection =
 573     Ctx->getELFSection(".debug_str.dwo", ELF::SHT_PROGBITS,
 574                        ELF::SHF_MERGE | ELF::SHF_STRINGS,
 575                        SectionKind::getMergeable1ByteCString());
 576   DwarfLineDWOSection =
 577     Ctx->getELFSection(".debug_line.dwo", ELF::SHT_PROGBITS, 0,
 578                        SectionKind::getMetadata());
 579   DwarfLocDWOSection =
 580     Ctx->getELFSection(".debug_loc.dwo", ELF::SHT_PROGBITS, 0,
 581                        SectionKind::getMetadata());
 582   DwarfStrOffDWOSection =
 583     Ctx->getELFSection(".debug_str_offsets.dwo", ELF::SHT_PROGBITS, 0,
 584                        SectionKind::getMetadata());
 585   DwarfAddrSection =
 586     Ctx->getELFSection(".debug_addr", ELF::SHT_PROGBITS, 0,
 587                        SectionKind::getMetadata());
 588
 589   StackMapSection =
 590     Ctx->getELFSection(".llvm_stackmaps", ELF::SHT_PROGBITS,
 591                        ELF::SHF_ALLOC,
 592                        SectionKind::getMetadata());
 593
 594 }
 595
 596
 597 void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
 598   bool IsWoA = T.getArch() == Triple::arm || T.getArch() == Triple::thumb;
 599
 600   CommDirectiveSupportsAlignment = true;
 601
 602   // COFF
 603   BSSSection =
 604     Ctx->getCOFFSection(".bss",
 605                         COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
 606                         COFF::IMAGE_SCN_MEM_READ |
 607                         COFF::IMAGE_SCN_MEM_WRITE,
 608                         SectionKind::getBSS());
 609   TextSection =
 610     Ctx->getCOFFSection(".text",
 611                         (IsWoA ? COFF::IMAGE_SCN_MEM_16BIT
 612                                : (COFF::SectionCharacteristics)0) |
 613                         COFF::IMAGE_SCN_CNT_CODE |
 614                         COFF::IMAGE_SCN_MEM_EXECUTE |
 615                         COFF::IMAGE_SCN_MEM_READ,
 616                         SectionKind::getText());
 617   DataSection =
 618     Ctx->getCOFFSection(".data",
 619                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 620                         COFF::IMAGE_SCN_MEM_READ |
 621                         COFF::IMAGE_SCN_MEM_WRITE,
 622                         SectionKind::getDataRel());
 623   ReadOnlySection =
 624     Ctx->getCOFFSection(".rdata",
 625                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 626                         COFF::IMAGE_SCN_MEM_READ,
 627                         SectionKind::getReadOnly());
 628
 629   if (T.isKnownWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) {
 630     StaticCtorSection =
 631       Ctx->getCOFFSection(".CRT$XCU",
 632                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 633                           COFF::IMAGE_SCN_MEM_READ,
 634                           SectionKind::getReadOnly());
 635     StaticDtorSection =
 636       Ctx->getCOFFSection(".CRT$XTX",
 637                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 638                           COFF::IMAGE_SCN_MEM_READ,
 639                           SectionKind::getReadOnly());
 640   } else {
 641     StaticCtorSection =
 642       Ctx->getCOFFSection(".ctors",
 643                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 644                           COFF::IMAGE_SCN_MEM_READ |
 645                           COFF::IMAGE_SCN_MEM_WRITE,
 646                           SectionKind::getDataRel());
 647     StaticDtorSection =
 648       Ctx->getCOFFSection(".dtors",
 649                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 650                           COFF::IMAGE_SCN_MEM_READ |
 651                           COFF::IMAGE_SCN_MEM_WRITE,
 652                           SectionKind::getDataRel());
 653   }
 654
 655   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
 656   // though it contains relocatable pointers.  In PIC mode, this is probably a
 657   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
 658   // adjusted or this should be a data section.
 659   assert(T.isOSWindows() && "Windows is the only supported COFF target");
 660   if (T.getArch() == Triple::x86_64) {
 661     // On Windows 64 with SEH, the LSDA is emitted into the .xdata section
 662     LSDASection = 0;
 663   } else {
 664     LSDASection = Ctx->getCOFFSection(".gcc_except_table",
 665                                       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 666                                           COFF::IMAGE_SCN_MEM_READ,
 667                                       SectionKind::getReadOnly());
 668   }
 669
 670   // Debug info.
 671   COFFDebugSymbolsSection =
 672     Ctx->getCOFFSection(".debug$S",
 673                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 674                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 675                         COFF::IMAGE_SCN_MEM_READ,
 676                         SectionKind::getMetadata());
 677
 678   DwarfAbbrevSection =
 679     Ctx->getCOFFSection(".debug_abbrev",
 680                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 681                         COFF::IMAGE_SCN_MEM_READ,
 682                         SectionKind::getMetadata());
 683   DwarfInfoSection =
 684     Ctx->getCOFFSection(".debug_info",
 685                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 686                         COFF::IMAGE_SCN_MEM_READ,
 687                         SectionKind::getMetadata());
 688   DwarfLineSection =
 689     Ctx->getCOFFSection(".debug_line",
 690                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 691                         COFF::IMAGE_SCN_MEM_READ,
 692                         SectionKind::getMetadata());
 693   DwarfFrameSection =
 694     Ctx->getCOFFSection(".debug_frame",
 695                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 696                         COFF::IMAGE_SCN_MEM_READ,
 697                         SectionKind::getMetadata());
 698   DwarfPubNamesSection =
 699     Ctx->getCOFFSection(".debug_pubnames",
 700                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 701                         COFF::IMAGE_SCN_MEM_READ,
 702                         SectionKind::getMetadata());
 703   DwarfPubTypesSection =
 704     Ctx->getCOFFSection(".debug_pubtypes",
 705                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 706                         COFF::IMAGE_SCN_MEM_READ,
 707                         SectionKind::getMetadata());
 708   DwarfGnuPubNamesSection =
 709     Ctx->getCOFFSection(".debug_gnu_pubnames",
 710                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 711                         COFF::IMAGE_SCN_MEM_READ,
 712                         SectionKind::getMetadata());
 713   DwarfGnuPubTypesSection =
 714     Ctx->getCOFFSection(".debug_gnu_pubtypes",
 715                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 716                         COFF::IMAGE_SCN_MEM_READ,
 717                         SectionKind::getMetadata());
 718   DwarfStrSection =
 719     Ctx->getCOFFSection(".debug_str",
 720                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 721                         COFF::IMAGE_SCN_MEM_READ,
 722                         SectionKind::getMetadata());
 723   DwarfLocSection =
 724     Ctx->getCOFFSection(".debug_loc",
 725                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 726                         COFF::IMAGE_SCN_MEM_READ,
 727                         SectionKind::getMetadata());
 728   DwarfARangesSection =
 729     Ctx->getCOFFSection(".debug_aranges",
 730                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 731                         COFF::IMAGE_SCN_MEM_READ,
 732                         SectionKind::getMetadata());
 733   DwarfRangesSection =
 734     Ctx->getCOFFSection(".debug_ranges",
 735                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 736                         COFF::IMAGE_SCN_MEM_READ,
 737                         SectionKind::getMetadata());
 738   DwarfMacroInfoSection =
 739     Ctx->getCOFFSection(".debug_macinfo",
 740                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 741                         COFF::IMAGE_SCN_MEM_READ,
 742                         SectionKind::getMetadata());
 743   DwarfInfoDWOSection =
 744       Ctx->getCOFFSection(".debug_info.dwo",
 745                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 746                           COFF::IMAGE_SCN_MEM_READ,
 747                           SectionKind::getMetadata());
 748   DwarfTypesDWOSection =
 749       Ctx->getCOFFSection(".debug_types.dwo", COFF::IMAGE_SCN_MEM_DISCARDABLE |
 750                                                   COFF::IMAGE_SCN_MEM_READ,
 751                           SectionKind::getMetadata());
 752   DwarfAbbrevDWOSection =
 753       Ctx->getCOFFSection(".debug_abbrev.dwo",
 754                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 755                           COFF::IMAGE_SCN_MEM_READ,
 756                           SectionKind::getMetadata());
 757   DwarfStrDWOSection =
 758       Ctx->getCOFFSection(".debug_str.dwo",
 759                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 760                           COFF::IMAGE_SCN_MEM_READ,
 761                           SectionKind::getMetadata());
 762   DwarfLineDWOSection =
 763       Ctx->getCOFFSection(".debug_line.dwo",
 764                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 765                           COFF::IMAGE_SCN_MEM_READ,
 766                           SectionKind::getMetadata());
 767   DwarfLocDWOSection =
 768       Ctx->getCOFFSection(".debug_loc.dwo",
 769                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 770                           COFF::IMAGE_SCN_MEM_READ,
 771                           SectionKind::getMetadata());
 772   DwarfStrOffDWOSection =
 773       Ctx->getCOFFSection(".debug_str_offsets.dwo",
 774                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
 775                           COFF::IMAGE_SCN_MEM_READ,
 776                           SectionKind::getMetadata());
 777
 778   DwarfAddrSection =
 779     Ctx->getCOFFSection(".debug_addr",
 780                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
 781                         COFF::IMAGE_SCN_MEM_READ,
 782                         SectionKind::getMetadata());
 783
 784   DrectveSection =
 785     Ctx->getCOFFSection(".drectve",
 786                         COFF::IMAGE_SCN_LNK_INFO |
 787                         COFF::IMAGE_SCN_LNK_REMOVE,
 788                         SectionKind::getMetadata());
 789
 790   PDataSection =
 791     Ctx->getCOFFSection(".pdata",
 792                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 793                         COFF::IMAGE_SCN_MEM_READ,
 794                         SectionKind::getDataRel());
 795
 796   XDataSection =
 797     Ctx->getCOFFSection(".xdata",
 798                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 799                         COFF::IMAGE_SCN_MEM_READ,
 800                         SectionKind::getDataRel());
 801
 802   TLSDataSection =
 803     Ctx->getCOFFSection(".tls$",
 804                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 805                         COFF::IMAGE_SCN_MEM_READ |
 806                         COFF::IMAGE_SCN_MEM_WRITE,
 807                         SectionKind::getDataRel());
 808 }
 809
 810 void MCObjectFileInfo::InitMCObjectFileInfo(StringRef T, Reloc::Model relocm,
 811                                             CodeModel::Model cm,
 812                                             MCContext &ctx) {
 813   RelocM = relocm;
 814   CMModel = cm;
 815   Ctx = &ctx;
 816
 817   // Common.
 818   CommDirectiveSupportsAlignment = true;
 819   SupportsWeakOmittedEHFrame = true;
 820   SupportsCompactUnwindWithoutEHFrame = false;
 821
 822   PersonalityEncoding = LSDAEncoding = FDECFIEncoding = TTypeEncoding =
 823       dwarf::DW_EH_PE_absptr;
 824
 825   CompactUnwindDwarfEHFrameOnly = 0;
 826
 827   EHFrameSection = nullptr;             // Created on demand.
 828   CompactUnwindSection = nullptr;       // Used only by selected targets.
 829   DwarfAccelNamesSection = nullptr;     // Used only by selected targets.
 830   DwarfAccelObjCSection = nullptr;      // Used only by selected targets.
 831   DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
 832   DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
 833
 834   TT = Triple(T);
 835
 836   Triple::ArchType Arch = TT.getArch();
 837   // FIXME: Checking for Arch here to filter out bogus triples such as
 838   // cellspu-apple-darwin. Perhaps we should fix in Triple?
 839   if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
 840        Arch == Triple::arm || Arch == Triple::thumb ||
 841        Arch == Triple::aarch64 ||
 842        Arch == Triple::ppc || Arch == Triple::ppc64 ||
 843        Arch == Triple::UnknownArch) &&
 844       (TT.isOSDarwin() || TT.isOSBinFormatMachO())) {
 845     Env = IsMachO;
 846     InitMachOMCObjectFileInfo(TT);
 847   } else if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
 848               Arch == Triple::arm || Arch == Triple::thumb) &&
 849              (TT.isOSWindows() && TT.getObjectFormat() == Triple::COFF)) {
 850     Env = IsCOFF;
 851     InitCOFFMCObjectFileInfo(TT);
 852   } else {
 853     Env = IsELF;
 854     InitELFMCObjectFileInfo(TT);
 855   }
 856 }
 857
 858 const MCSection *MCObjectFileInfo::getDwarfTypesSection(uint64_t Hash) const {
 859   return Ctx->getELFSection(".debug_types", ELF::SHT_PROGBITS, ELF::SHF_GROUP,
 860                             SectionKind::getMetadata(), 0, utostr(Hash));
 861 }
 862
 863 void MCObjectFileInfo::InitEHFrameSection() {
 864   if (Env == IsMachO)
 865     EHFrameSection =
 866       Ctx->getMachOSection("__TEXT", "__eh_frame",
 867                            MachO::S_COALESCED |
 868                            MachO::S_ATTR_NO_TOC |
 869                            MachO::S_ATTR_STRIP_STATIC_SYMS |
 870                            MachO::S_ATTR_LIVE_SUPPORT,
 871                            SectionKind::getReadOnly());
 872   else if (Env == IsELF)
 873     EHFrameSection =
 874       Ctx->getELFSection(".eh_frame", EHSectionType,
 875                          EHSectionFlags,
 876                          SectionKind::getDataRel());
 877   else
 878     EHFrameSection =
 879       Ctx->getCOFFSection(".eh_frame",
 880                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 881                           COFF::IMAGE_SCN_MEM_READ |
 882                           COFF::IMAGE_SCN_MEM_WRITE,
 883                           SectionKind::getDataRel());
 884 }