contrib/llvm/lib/MC/MCObjectFileInfo.cpp

   1 //===-- MCObjectFileInfo.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/BinaryFormat/COFF.h"
  14 #include "llvm/BinaryFormat/ELF.h"
  15 #include "llvm/MC/MCAsmInfo.h"
  16 #include "llvm/MC/MCContext.h"
  17 #include "llvm/MC/MCSection.h"
  18 #include "llvm/MC/MCSectionCOFF.h"
  19 #include "llvm/MC/MCSectionELF.h"
  20 #include "llvm/MC/MCSectionMachO.h"
  21 #include "llvm/MC/MCSectionWasm.h"
  22
  23 using namespace llvm;
  24
  25 static bool useCompactUnwind(const Triple &T) {
  26   // Only on darwin.
  27   if (!T.isOSDarwin())
  28     return false;
  29
  30   // aarch64 always has it.
  31   if (T.getArch() == Triple::aarch64)
  32     return true;
  33
  34   // armv7k always has it.
  35   if (T.isWatchABI())
  36     return true;
  37
  38   // Use it on newer version of OS X.
  39   if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6))
  40     return true;
  41
  42   // And the iOS simulator.
  43   if (T.isiOS() &&
  44       (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86))
  45     return true;
  46
  47   return false;
  48 }
  49
  50 void MCObjectFileInfo::initMachOMCObjectFileInfo(const Triple &T) {
  51   // MachO
  52   SupportsWeakOmittedEHFrame = false;
  53
  54   EHFrameSection = Ctx->getMachOSection(
  55       "__TEXT", "__eh_frame",
  56       MachO::S_COALESCED | MachO::S_ATTR_NO_TOC |
  57           MachO::S_ATTR_STRIP_STATIC_SYMS | MachO::S_ATTR_LIVE_SUPPORT,
  58       SectionKind::getReadOnly());
  59
  60   if (T.isOSDarwin() && T.getArch() == Triple::aarch64)
  61     SupportsCompactUnwindWithoutEHFrame = true;
  62
  63   if (T.isWatchABI())
  64     OmitDwarfIfHaveCompactUnwind = true;
  65
  66   FDECFIEncoding = dwarf::DW_EH_PE_pcrel;
  67
  68   // .comm doesn't support alignment before Leopard.
  69   if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
  70     CommDirectiveSupportsAlignment = false;
  71
  72   TextSection // .text
  73     = Ctx->getMachOSection("__TEXT", "__text",
  74                            MachO::S_ATTR_PURE_INSTRUCTIONS,
  75                            SectionKind::getText());
  76   DataSection // .data
  77       = Ctx->getMachOSection("__DATA", "__data", 0, SectionKind::getData());
  78
  79   // BSSSection might not be expected initialized on msvc.
  80   BSSSection = nullptr;
  81
  82   TLSDataSection // .tdata
  83       = Ctx->getMachOSection("__DATA", "__thread_data",
  84                              MachO::S_THREAD_LOCAL_REGULAR,
  85                              SectionKind::getData());
  86   TLSBSSSection // .tbss
  87     = Ctx->getMachOSection("__DATA", "__thread_bss",
  88                            MachO::S_THREAD_LOCAL_ZEROFILL,
  89                            SectionKind::getThreadBSS());
  90
  91   // TODO: Verify datarel below.
  92   TLSTLVSection // .tlv
  93       = Ctx->getMachOSection("__DATA", "__thread_vars",
  94                              MachO::S_THREAD_LOCAL_VARIABLES,
  95                              SectionKind::getData());
  96
  97   TLSThreadInitSection = Ctx->getMachOSection(
  98       "__DATA", "__thread_init", MachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
  99       SectionKind::getData());
 100
 101   CStringSection // .cstring
 102     = Ctx->getMachOSection("__TEXT", "__cstring",
 103                            MachO::S_CSTRING_LITERALS,
 104                            SectionKind::getMergeable1ByteCString());
 105   UStringSection
 106     = Ctx->getMachOSection("__TEXT","__ustring", 0,
 107                            SectionKind::getMergeable2ByteCString());
 108   FourByteConstantSection // .literal4
 109     = Ctx->getMachOSection("__TEXT", "__literal4",
 110                            MachO::S_4BYTE_LITERALS,
 111                            SectionKind::getMergeableConst4());
 112   EightByteConstantSection // .literal8
 113     = Ctx->getMachOSection("__TEXT", "__literal8",
 114                            MachO::S_8BYTE_LITERALS,
 115                            SectionKind::getMergeableConst8());
 116
 117   SixteenByteConstantSection // .literal16
 118       = Ctx->getMachOSection("__TEXT", "__literal16",
 119                              MachO::S_16BYTE_LITERALS,
 120                              SectionKind::getMergeableConst16());
 121
 122   ReadOnlySection  // .const
 123     = Ctx->getMachOSection("__TEXT", "__const", 0,
 124                            SectionKind::getReadOnly());
 125
 126   // If the target is not powerpc, map the coal sections to the non-coal
 127   // sections.
 128   //
 129   // "__TEXT/__textcoal_nt" => section "__TEXT/__text"
 130   // "__TEXT/__const_coal"  => section "__TEXT/__const"
 131   // "__DATA/__datacoal_nt" => section "__DATA/__data"
 132   Triple::ArchType ArchTy = T.getArch();
 133
 134   ConstDataSection  // .const_data
 135     = Ctx->getMachOSection("__DATA", "__const", 0,
 136                            SectionKind::getReadOnlyWithRel());
 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 = Ctx->getMachOSection(
 149         "__DATA", "__datacoal_nt", MachO::S_COALESCED, SectionKind::getData());
 150     ConstDataCoalSection = DataCoalSection;
 151   } else {
 152     TextCoalSection = TextSection;
 153     ConstTextCoalSection = ReadOnlySection;
 154     DataCoalSection = DataSection;
 155     ConstDataCoalSection = ConstDataSection;
 156   }
 157
 158   DataCommonSection
 159     = Ctx->getMachOSection("__DATA","__common",
 160                            MachO::S_ZEROFILL,
 161                            SectionKind::getBSS());
 162   DataBSSSection
 163     = Ctx->getMachOSection("__DATA","__bss", MachO::S_ZEROFILL,
 164                            SectionKind::getBSS());
 165
 166
 167   LazySymbolPointerSection
 168     = Ctx->getMachOSection("__DATA", "__la_symbol_ptr",
 169                            MachO::S_LAZY_SYMBOL_POINTERS,
 170                            SectionKind::getMetadata());
 171   NonLazySymbolPointerSection
 172     = Ctx->getMachOSection("__DATA", "__nl_symbol_ptr",
 173                            MachO::S_NON_LAZY_SYMBOL_POINTERS,
 174                            SectionKind::getMetadata());
 175
 176   ThreadLocalPointerSection
 177     = Ctx->getMachOSection("__DATA", "__thread_ptr",
 178                            MachO::S_THREAD_LOCAL_VARIABLE_POINTERS,
 179                            SectionKind::getMetadata());
 180
 181   // Exception Handling.
 182   LSDASection = Ctx->getMachOSection("__TEXT", "__gcc_except_tab", 0,
 183                                      SectionKind::getReadOnlyWithRel());
 184
 185   COFFDebugSymbolsSection = nullptr;
 186   COFFDebugTypesSection = nullptr;
 187   COFFGlobalTypeHashesSection = nullptr;
 188
 189   if (useCompactUnwind(T)) {
 190     CompactUnwindSection =
 191         Ctx->getMachOSection("__LD", "__compact_unwind", MachO::S_ATTR_DEBUG,
 192                              SectionKind::getReadOnly());
 193
 194     if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86)
 195       CompactUnwindDwarfEHFrameOnly = 0x04000000;  // UNWIND_X86_64_MODE_DWARF
 196     else if (T.getArch() == Triple::aarch64)
 197       CompactUnwindDwarfEHFrameOnly = 0x03000000;  // UNWIND_ARM64_MODE_DWARF
 198     else if (T.getArch() == Triple::arm || T.getArch() == Triple::thumb)
 199       CompactUnwindDwarfEHFrameOnly = 0x04000000;  // UNWIND_ARM_MODE_DWARF
 200   }
 201
 202   // Debug Information.
 203   DwarfDebugNamesSection =
 204       Ctx->getMachOSection("__DWARF", "__debug_names", MachO::S_ATTR_DEBUG,
 205                            SectionKind::getMetadata(), "debug_names_begin");
 206   DwarfAccelNamesSection =
 207       Ctx->getMachOSection("__DWARF", "__apple_names", MachO::S_ATTR_DEBUG,
 208                            SectionKind::getMetadata(), "names_begin");
 209   DwarfAccelObjCSection =
 210       Ctx->getMachOSection("__DWARF", "__apple_objc", MachO::S_ATTR_DEBUG,
 211                            SectionKind::getMetadata(), "objc_begin");
 212   // 16 character section limit...
 213   DwarfAccelNamespaceSection =
 214       Ctx->getMachOSection("__DWARF", "__apple_namespac", MachO::S_ATTR_DEBUG,
 215                            SectionKind::getMetadata(), "namespac_begin");
 216   DwarfAccelTypesSection =
 217       Ctx->getMachOSection("__DWARF", "__apple_types", MachO::S_ATTR_DEBUG,
 218                            SectionKind::getMetadata(), "types_begin");
 219
 220   DwarfSwiftASTSection =
 221       Ctx->getMachOSection("__DWARF", "__swift_ast", MachO::S_ATTR_DEBUG,
 222                            SectionKind::getMetadata());
 223
 224   DwarfAbbrevSection =
 225       Ctx->getMachOSection("__DWARF", "__debug_abbrev", MachO::S_ATTR_DEBUG,
 226                            SectionKind::getMetadata(), "section_abbrev");
 227   DwarfInfoSection =
 228       Ctx->getMachOSection("__DWARF", "__debug_info", MachO::S_ATTR_DEBUG,
 229                            SectionKind::getMetadata(), "section_info");
 230   DwarfLineSection =
 231       Ctx->getMachOSection("__DWARF", "__debug_line", MachO::S_ATTR_DEBUG,
 232                            SectionKind::getMetadata(), "section_line");
 233   DwarfLineStrSection =
 234       Ctx->getMachOSection("__DWARF", "__debug_line_str", MachO::S_ATTR_DEBUG,
 235                            SectionKind::getMetadata(), "section_line_str");
 236   DwarfFrameSection =
 237       Ctx->getMachOSection("__DWARF", "__debug_frame", MachO::S_ATTR_DEBUG,
 238                            SectionKind::getMetadata());
 239   DwarfPubNamesSection =
 240       Ctx->getMachOSection("__DWARF", "__debug_pubnames", MachO::S_ATTR_DEBUG,
 241                            SectionKind::getMetadata());
 242   DwarfPubTypesSection =
 243       Ctx->getMachOSection("__DWARF", "__debug_pubtypes", MachO::S_ATTR_DEBUG,
 244                            SectionKind::getMetadata());
 245   DwarfGnuPubNamesSection =
 246       Ctx->getMachOSection("__DWARF", "__debug_gnu_pubn", MachO::S_ATTR_DEBUG,
 247                            SectionKind::getMetadata());
 248   DwarfGnuPubTypesSection =
 249       Ctx->getMachOSection("__DWARF", "__debug_gnu_pubt", MachO::S_ATTR_DEBUG,
 250                            SectionKind::getMetadata());
 251   DwarfStrSection =
 252       Ctx->getMachOSection("__DWARF", "__debug_str", MachO::S_ATTR_DEBUG,
 253                            SectionKind::getMetadata(), "info_string");
 254   DwarfStrOffSection =
 255       Ctx->getMachOSection("__DWARF", "__debug_str_offs", MachO::S_ATTR_DEBUG,
 256                            SectionKind::getMetadata(), "section_str_off");
 257   DwarfAddrSection =
 258       Ctx->getMachOSection("__DWARF", "__debug_addr", MachO::S_ATTR_DEBUG,
 259                            SectionKind::getMetadata(), "section_info");
 260   DwarfLocSection =
 261       Ctx->getMachOSection("__DWARF", "__debug_loc", MachO::S_ATTR_DEBUG,
 262                            SectionKind::getMetadata(), "section_debug_loc");
 263   DwarfLoclistsSection =
 264       Ctx->getMachOSection("__DWARF", "__debug_loclists", MachO::S_ATTR_DEBUG,
 265                            SectionKind::getMetadata(), "section_debug_loc");
 266
 267   DwarfARangesSection =
 268       Ctx->getMachOSection("__DWARF", "__debug_aranges", MachO::S_ATTR_DEBUG,
 269                            SectionKind::getMetadata());
 270   DwarfRangesSection =
 271       Ctx->getMachOSection("__DWARF", "__debug_ranges", MachO::S_ATTR_DEBUG,
 272                            SectionKind::getMetadata(), "debug_range");
 273   DwarfRnglistsSection =
 274       Ctx->getMachOSection("__DWARF", "__debug_rnglists", MachO::S_ATTR_DEBUG,
 275                            SectionKind::getMetadata(), "debug_range");
 276   DwarfMacinfoSection =
 277       Ctx->getMachOSection("__DWARF", "__debug_macinfo", MachO::S_ATTR_DEBUG,
 278                            SectionKind::getMetadata(), "debug_macinfo");
 279   DwarfDebugInlineSection =
 280       Ctx->getMachOSection("__DWARF", "__debug_inlined", MachO::S_ATTR_DEBUG,
 281                            SectionKind::getMetadata());
 282   DwarfCUIndexSection =
 283       Ctx->getMachOSection("__DWARF", "__debug_cu_index", MachO::S_ATTR_DEBUG,
 284                            SectionKind::getMetadata());
 285   DwarfTUIndexSection =
 286       Ctx->getMachOSection("__DWARF", "__debug_tu_index", MachO::S_ATTR_DEBUG,
 287                            SectionKind::getMetadata());
 288   StackMapSection = Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps",
 289                                          0, SectionKind::getMetadata());
 290
 291   FaultMapSection = Ctx->getMachOSection("__LLVM_FAULTMAPS", "__llvm_faultmaps",
 292                                          0, SectionKind::getMetadata());
 293
 294   TLSExtraDataSection = TLSTLVSection;
 295 }
 296
 297 void MCObjectFileInfo::initELFMCObjectFileInfo(const Triple &T, bool Large) {
 298   switch (T.getArch()) {
 299   case Triple::mips:
 300   case Triple::mipsel:
 301   case Triple::mips64:
 302   case Triple::mips64el:
 303     FDECFIEncoding = Ctx->getAsmInfo()->getCodePointerSize() == 4
 304                          ? dwarf::DW_EH_PE_sdata4
 305                          : dwarf::DW_EH_PE_sdata8;
 306     break;
 307   case Triple::ppc64:
 308   case Triple::ppc64le:
 309   case Triple::x86_64:
 310     FDECFIEncoding = dwarf::DW_EH_PE_pcrel |
 311                      (Large ? dwarf::DW_EH_PE_sdata8 : dwarf::DW_EH_PE_sdata4);
 312     break;
 313   case Triple::bpfel:
 314   case Triple::bpfeb:
 315     FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
 316     break;
 317   case Triple::hexagon:
 318     FDECFIEncoding =
 319         PositionIndependent ? dwarf::DW_EH_PE_pcrel : dwarf::DW_EH_PE_absptr;
 320     break;
 321   default:
 322     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 323     break;
 324   }
 325
 326   unsigned EHSectionType = T.getArch() == Triple::x86_64
 327                                ? ELF::SHT_X86_64_UNWIND
 328                                : ELF::SHT_PROGBITS;
 329
 330   // Solaris requires different flags for .eh_frame to seemingly every other
 331   // platform.
 332   unsigned EHSectionFlags = ELF::SHF_ALLOC;
 333   if (T.isOSSolaris() && T.getArch() != Triple::x86_64)
 334     EHSectionFlags |= ELF::SHF_WRITE;
 335
 336   // ELF
 337   BSSSection = Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
 338                                   ELF::SHF_WRITE | ELF::SHF_ALLOC);
 339
 340   TextSection = Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
 341                                    ELF::SHF_EXECINSTR | ELF::SHF_ALLOC);
 342
 343   DataSection = Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
 344                                    ELF::SHF_WRITE | ELF::SHF_ALLOC);
 345
 346   ReadOnlySection =
 347       Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
 348
 349   TLSDataSection =
 350       Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
 351                          ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
 352
 353   TLSBSSSection = Ctx->getELFSection(
 354       ".tbss", ELF::SHT_NOBITS, ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
 355
 356   DataRelROSection = Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
 357                                         ELF::SHF_ALLOC | ELF::SHF_WRITE);
 358
 359   MergeableConst4Section =
 360       Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
 361                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 4, "");
 362
 363   MergeableConst8Section =
 364       Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
 365                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 8, "");
 366
 367   MergeableConst16Section =
 368       Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
 369                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 16, "");
 370
 371   MergeableConst32Section =
 372       Ctx->getELFSection(".rodata.cst32", ELF::SHT_PROGBITS,
 373                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 32, "");
 374
 375   // Exception Handling Sections.
 376
 377   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
 378   // it contains relocatable pointers.  In PIC mode, this is probably a big
 379   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
 380   // adjusted or this should be a data section.
 381   LSDASection = Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
 382                                    ELF::SHF_ALLOC);
 383
 384   COFFDebugSymbolsSection = nullptr;
 385   COFFDebugTypesSection = nullptr;
 386
 387   unsigned DebugSecType = ELF::SHT_PROGBITS;
 388
 389   // MIPS .debug_* sections should have SHT_MIPS_DWARF section type
 390   // to distinguish among sections contain DWARF and ECOFF debug formats.
 391   // Sections with ECOFF debug format are obsoleted and marked by SHT_PROGBITS.
 392   if (T.isMIPS())
 393     DebugSecType = ELF::SHT_MIPS_DWARF;
 394
 395   // Debug Info Sections.
 396   DwarfAbbrevSection =
 397       Ctx->getELFSection(".debug_abbrev", DebugSecType, 0);
 398   DwarfInfoSection = Ctx->getELFSection(".debug_info", DebugSecType, 0);
 399   DwarfLineSection = Ctx->getELFSection(".debug_line", DebugSecType, 0);
 400   DwarfLineStrSection =
 401       Ctx->getELFSection(".debug_line_str", DebugSecType,
 402                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
 403   DwarfFrameSection = Ctx->getELFSection(".debug_frame", DebugSecType, 0);
 404   DwarfPubNamesSection =
 405       Ctx->getELFSection(".debug_pubnames", DebugSecType, 0);
 406   DwarfPubTypesSection =
 407       Ctx->getELFSection(".debug_pubtypes", DebugSecType, 0);
 408   DwarfGnuPubNamesSection =
 409       Ctx->getELFSection(".debug_gnu_pubnames", DebugSecType, 0);
 410   DwarfGnuPubTypesSection =
 411       Ctx->getELFSection(".debug_gnu_pubtypes", DebugSecType, 0);
 412   DwarfStrSection =
 413       Ctx->getELFSection(".debug_str", DebugSecType,
 414                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
 415   DwarfLocSection = Ctx->getELFSection(".debug_loc", DebugSecType, 0);
 416   DwarfARangesSection =
 417       Ctx->getELFSection(".debug_aranges", DebugSecType, 0);
 418   DwarfRangesSection =
 419       Ctx->getELFSection(".debug_ranges", DebugSecType, 0);
 420   DwarfMacinfoSection =
 421       Ctx->getELFSection(".debug_macinfo", DebugSecType, 0);
 422
 423   // DWARF5 Experimental Debug Info
 424
 425   // Accelerator Tables
 426   DwarfDebugNamesSection =
 427       Ctx->getELFSection(".debug_names", ELF::SHT_PROGBITS, 0);
 428   DwarfAccelNamesSection =
 429       Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0);
 430   DwarfAccelObjCSection =
 431       Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0);
 432   DwarfAccelNamespaceSection =
 433       Ctx->getELFSection(".apple_namespaces", ELF::SHT_PROGBITS, 0);
 434   DwarfAccelTypesSection =
 435       Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0);
 436
 437   // String Offset and Address Sections
 438   DwarfStrOffSection =
 439       Ctx->getELFSection(".debug_str_offsets", DebugSecType, 0);
 440   DwarfAddrSection = Ctx->getELFSection(".debug_addr", DebugSecType, 0);
 441   DwarfRnglistsSection = Ctx->getELFSection(".debug_rnglists", DebugSecType, 0);
 442   DwarfLoclistsSection = Ctx->getELFSection(".debug_loclists", DebugSecType, 0);
 443
 444   // Fission Sections
 445   DwarfInfoDWOSection =
 446       Ctx->getELFSection(".debug_info.dwo", DebugSecType, ELF::SHF_EXCLUDE);
 447   DwarfTypesDWOSection =
 448       Ctx->getELFSection(".debug_types.dwo", DebugSecType, ELF::SHF_EXCLUDE);
 449   DwarfAbbrevDWOSection =
 450       Ctx->getELFSection(".debug_abbrev.dwo", DebugSecType, ELF::SHF_EXCLUDE);
 451   DwarfStrDWOSection = Ctx->getELFSection(
 452       ".debug_str.dwo", DebugSecType,
 453       ELF::SHF_MERGE | ELF::SHF_STRINGS | ELF::SHF_EXCLUDE, 1, "");
 454   DwarfLineDWOSection =
 455       Ctx->getELFSection(".debug_line.dwo", DebugSecType, ELF::SHF_EXCLUDE);
 456   DwarfLocDWOSection =
 457       Ctx->getELFSection(".debug_loc.dwo", DebugSecType, ELF::SHF_EXCLUDE);
 458   DwarfStrOffDWOSection = Ctx->getELFSection(".debug_str_offsets.dwo",
 459                                              DebugSecType, ELF::SHF_EXCLUDE);
 460   DwarfRnglistsDWOSection =
 461       Ctx->getELFSection(".debug_rnglists.dwo", DebugSecType, ELF::SHF_EXCLUDE);
 462
 463   // DWP Sections
 464   DwarfCUIndexSection =
 465       Ctx->getELFSection(".debug_cu_index", DebugSecType, 0);
 466   DwarfTUIndexSection =
 467       Ctx->getELFSection(".debug_tu_index", DebugSecType, 0);
 468
 469   StackMapSection =
 470       Ctx->getELFSection(".llvm_stackmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
 471
 472   FaultMapSection =
 473       Ctx->getELFSection(".llvm_faultmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
 474
 475   EHFrameSection =
 476       Ctx->getELFSection(".eh_frame", EHSectionType, EHSectionFlags);
 477
 478   StackSizesSection = Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, 0);
 479 }
 480
 481 void MCObjectFileInfo::initCOFFMCObjectFileInfo(const Triple &T) {
 482   EHFrameSection =
 483       Ctx->getCOFFSection(".eh_frame", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 484                                            COFF::IMAGE_SCN_MEM_READ,
 485                           SectionKind::getData());
 486
 487   // Set the `IMAGE_SCN_MEM_16BIT` flag when compiling for thumb mode.  This is
 488   // used to indicate to the linker that the text segment contains thumb instructions
 489   // and to set the ISA selection bit for calls accordingly.
 490   const bool IsThumb = T.getArch() == Triple::thumb;
 491
 492   CommDirectiveSupportsAlignment = true;
 493
 494   // COFF
 495   BSSSection = Ctx->getCOFFSection(
 496       ".bss", COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
 497                   COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
 498       SectionKind::getBSS());
 499   TextSection = Ctx->getCOFFSection(
 500       ".text",
 501       (IsThumb ? COFF::IMAGE_SCN_MEM_16BIT : (COFF::SectionCharacteristics)0) |
 502           COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE |
 503           COFF::IMAGE_SCN_MEM_READ,
 504       SectionKind::getText());
 505   DataSection = Ctx->getCOFFSection(
 506       ".data", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
 507                    COFF::IMAGE_SCN_MEM_WRITE,
 508       SectionKind::getData());
 509   ReadOnlySection = Ctx->getCOFFSection(
 510       ".rdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
 511       SectionKind::getReadOnly());
 512
 513   if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::aarch64) {
 514     // On Windows 64 with SEH, the LSDA is emitted into the .xdata section
 515     LSDASection = nullptr;
 516   } else {
 517     LSDASection = Ctx->getCOFFSection(".gcc_except_table",
 518                                       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 519                                           COFF::IMAGE_SCN_MEM_READ,
 520                                       SectionKind::getReadOnly());
 521   }
 522
 523   // Debug info.
 524   COFFDebugSymbolsSection =
 525       Ctx->getCOFFSection(".debug$S", (COFF::IMAGE_SCN_MEM_DISCARDABLE |
 526                                        COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 527                                        COFF::IMAGE_SCN_MEM_READ),
 528                           SectionKind::getMetadata());
 529   COFFDebugTypesSection =
 530       Ctx->getCOFFSection(".debug$T", (COFF::IMAGE_SCN_MEM_DISCARDABLE |
 531                                        COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 532                                        COFF::IMAGE_SCN_MEM_READ),
 533                           SectionKind::getMetadata());
 534   COFFGlobalTypeHashesSection = Ctx->getCOFFSection(
 535       ".debug$H",
 536       (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 537        COFF::IMAGE_SCN_MEM_READ),
 538       SectionKind::getMetadata());
 539
 540   DwarfAbbrevSection = Ctx->getCOFFSection(
 541       ".debug_abbrev",
 542       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 543           COFF::IMAGE_SCN_MEM_READ,
 544       SectionKind::getMetadata(), "section_abbrev");
 545   DwarfInfoSection = Ctx->getCOFFSection(
 546       ".debug_info",
 547       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 548           COFF::IMAGE_SCN_MEM_READ,
 549       SectionKind::getMetadata(), "section_info");
 550   DwarfLineSection = Ctx->getCOFFSection(
 551       ".debug_line",
 552       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 553           COFF::IMAGE_SCN_MEM_READ,
 554       SectionKind::getMetadata(), "section_line");
 555   DwarfLineStrSection = Ctx->getCOFFSection(
 556       ".debug_line_str",
 557       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 558           COFF::IMAGE_SCN_MEM_READ,
 559       SectionKind::getMetadata(), "section_line_str");
 560   DwarfFrameSection = Ctx->getCOFFSection(
 561       ".debug_frame",
 562       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 563           COFF::IMAGE_SCN_MEM_READ,
 564       SectionKind::getMetadata());
 565   DwarfPubNamesSection = Ctx->getCOFFSection(
 566       ".debug_pubnames",
 567       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 568           COFF::IMAGE_SCN_MEM_READ,
 569       SectionKind::getMetadata());
 570   DwarfPubTypesSection = Ctx->getCOFFSection(
 571       ".debug_pubtypes",
 572       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 573           COFF::IMAGE_SCN_MEM_READ,
 574       SectionKind::getMetadata());
 575   DwarfGnuPubNamesSection = Ctx->getCOFFSection(
 576       ".debug_gnu_pubnames",
 577       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 578           COFF::IMAGE_SCN_MEM_READ,
 579       SectionKind::getMetadata());
 580   DwarfGnuPubTypesSection = Ctx->getCOFFSection(
 581       ".debug_gnu_pubtypes",
 582       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 583           COFF::IMAGE_SCN_MEM_READ,
 584       SectionKind::getMetadata());
 585   DwarfStrSection = Ctx->getCOFFSection(
 586       ".debug_str",
 587       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 588           COFF::IMAGE_SCN_MEM_READ,
 589       SectionKind::getMetadata(), "info_string");
 590   DwarfStrOffSection = Ctx->getCOFFSection(
 591       ".debug_str_offsets",
 592       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 593           COFF::IMAGE_SCN_MEM_READ,
 594       SectionKind::getMetadata(), "section_str_off");
 595   DwarfLocSection = Ctx->getCOFFSection(
 596       ".debug_loc",
 597       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 598           COFF::IMAGE_SCN_MEM_READ,
 599       SectionKind::getMetadata(), "section_debug_loc");
 600   DwarfARangesSection = Ctx->getCOFFSection(
 601       ".debug_aranges",
 602       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 603           COFF::IMAGE_SCN_MEM_READ,
 604       SectionKind::getMetadata());
 605   DwarfRangesSection = Ctx->getCOFFSection(
 606       ".debug_ranges",
 607       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 608           COFF::IMAGE_SCN_MEM_READ,
 609       SectionKind::getMetadata(), "debug_range");
 610   DwarfMacinfoSection = Ctx->getCOFFSection(
 611       ".debug_macinfo",
 612       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 613           COFF::IMAGE_SCN_MEM_READ,
 614       SectionKind::getMetadata(), "debug_macinfo");
 615   DwarfInfoDWOSection = Ctx->getCOFFSection(
 616       ".debug_info.dwo",
 617       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 618           COFF::IMAGE_SCN_MEM_READ,
 619       SectionKind::getMetadata(), "section_info_dwo");
 620   DwarfTypesDWOSection = Ctx->getCOFFSection(
 621       ".debug_types.dwo",
 622       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 623           COFF::IMAGE_SCN_MEM_READ,
 624       SectionKind::getMetadata(), "section_types_dwo");
 625   DwarfAbbrevDWOSection = Ctx->getCOFFSection(
 626       ".debug_abbrev.dwo",
 627       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 628           COFF::IMAGE_SCN_MEM_READ,
 629       SectionKind::getMetadata(), "section_abbrev_dwo");
 630   DwarfStrDWOSection = Ctx->getCOFFSection(
 631       ".debug_str.dwo",
 632       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 633           COFF::IMAGE_SCN_MEM_READ,
 634       SectionKind::getMetadata(), "skel_string");
 635   DwarfLineDWOSection = Ctx->getCOFFSection(
 636       ".debug_line.dwo",
 637       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 638           COFF::IMAGE_SCN_MEM_READ,
 639       SectionKind::getMetadata());
 640   DwarfLocDWOSection = Ctx->getCOFFSection(
 641       ".debug_loc.dwo",
 642       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 643           COFF::IMAGE_SCN_MEM_READ,
 644       SectionKind::getMetadata(), "skel_loc");
 645   DwarfStrOffDWOSection = Ctx->getCOFFSection(
 646       ".debug_str_offsets.dwo",
 647       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 648           COFF::IMAGE_SCN_MEM_READ,
 649       SectionKind::getMetadata(), "section_str_off_dwo");
 650   DwarfAddrSection = Ctx->getCOFFSection(
 651       ".debug_addr",
 652       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 653           COFF::IMAGE_SCN_MEM_READ,
 654       SectionKind::getMetadata(), "addr_sec");
 655   DwarfCUIndexSection = Ctx->getCOFFSection(
 656       ".debug_cu_index",
 657       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 658           COFF::IMAGE_SCN_MEM_READ,
 659       SectionKind::getMetadata());
 660   DwarfTUIndexSection = Ctx->getCOFFSection(
 661       ".debug_tu_index",
 662       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 663           COFF::IMAGE_SCN_MEM_READ,
 664       SectionKind::getMetadata());
 665   DwarfDebugNamesSection = Ctx->getCOFFSection(
 666       ".debug_names",
 667       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 668           COFF::IMAGE_SCN_MEM_READ,
 669       SectionKind::getMetadata(), "debug_names_begin");
 670   DwarfAccelNamesSection = Ctx->getCOFFSection(
 671       ".apple_names",
 672       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 673           COFF::IMAGE_SCN_MEM_READ,
 674       SectionKind::getMetadata(), "names_begin");
 675   DwarfAccelNamespaceSection = Ctx->getCOFFSection(
 676       ".apple_namespaces",
 677       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 678           COFF::IMAGE_SCN_MEM_READ,
 679       SectionKind::getMetadata(), "namespac_begin");
 680   DwarfAccelTypesSection = Ctx->getCOFFSection(
 681       ".apple_types",
 682       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 683           COFF::IMAGE_SCN_MEM_READ,
 684       SectionKind::getMetadata(), "types_begin");
 685   DwarfAccelObjCSection = Ctx->getCOFFSection(
 686       ".apple_objc",
 687       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 688           COFF::IMAGE_SCN_MEM_READ,
 689       SectionKind::getMetadata(), "objc_begin");
 690
 691   DrectveSection = Ctx->getCOFFSection(
 692       ".drectve", COFF::IMAGE_SCN_LNK_INFO | COFF::IMAGE_SCN_LNK_REMOVE,
 693       SectionKind::getMetadata());
 694
 695   PDataSection = Ctx->getCOFFSection(
 696       ".pdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
 697       SectionKind::getData());
 698
 699   XDataSection = Ctx->getCOFFSection(
 700       ".xdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
 701       SectionKind::getData());
 702
 703   SXDataSection = Ctx->getCOFFSection(".sxdata", COFF::IMAGE_SCN_LNK_INFO,
 704                                       SectionKind::getMetadata());
 705
 706   GFIDsSection = Ctx->getCOFFSection(".gfids$y",
 707                                      COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 708                                          COFF::IMAGE_SCN_MEM_READ,
 709                                      SectionKind::getMetadata());
 710
 711   TLSDataSection = Ctx->getCOFFSection(
 712       ".tls$", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
 713                    COFF::IMAGE_SCN_MEM_WRITE,
 714       SectionKind::getData());
 715
 716   StackMapSection = Ctx->getCOFFSection(".llvm_stackmaps",
 717                                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 718                                             COFF::IMAGE_SCN_MEM_READ,
 719                                         SectionKind::getReadOnly());
 720 }
 721
 722 void MCObjectFileInfo::initWasmMCObjectFileInfo(const Triple &T) {
 723   TextSection = Ctx->getWasmSection(".text", SectionKind::getText());
 724   DataSection = Ctx->getWasmSection(".data", SectionKind::getData());
 725
 726   DwarfLineSection =
 727       Ctx->getWasmSection(".debug_line", SectionKind::getMetadata());
 728   DwarfLineStrSection =
 729       Ctx->getWasmSection(".debug_line_str", SectionKind::getMetadata());
 730   DwarfStrSection =
 731       Ctx->getWasmSection(".debug_str", SectionKind::getMetadata());
 732   DwarfLocSection =
 733       Ctx->getWasmSection(".debug_loc", SectionKind::getMetadata());
 734   DwarfAbbrevSection =
 735       Ctx->getWasmSection(".debug_abbrev", SectionKind::getMetadata());
 736   DwarfARangesSection = Ctx->getWasmSection(".debug_aranges", SectionKind::getMetadata());
 737   DwarfRangesSection =
 738       Ctx->getWasmSection(".debug_ranges", SectionKind::getMetadata());
 739   DwarfMacinfoSection =
 740       Ctx->getWasmSection(".debug_macinfo", SectionKind::getMetadata());
 741   DwarfAddrSection = Ctx->getWasmSection(".debug_addr", SectionKind::getMetadata());
 742   DwarfCUIndexSection = Ctx->getWasmSection(".debug_cu_index", SectionKind::getMetadata());
 743   DwarfTUIndexSection = Ctx->getWasmSection(".debug_tu_index", SectionKind::getMetadata());
 744   DwarfInfoSection =
 745       Ctx->getWasmSection(".debug_info", SectionKind::getMetadata());
 746   DwarfFrameSection = Ctx->getWasmSection(".debug_frame", SectionKind::getMetadata());
 747   DwarfPubNamesSection = Ctx->getWasmSection(".debug_pubnames", SectionKind::getMetadata());
 748   DwarfPubTypesSection = Ctx->getWasmSection(".debug_pubtypes", SectionKind::getMetadata());
 749
 750   // Wasm use data section for LSDA.
 751   // TODO Consider putting each function's exception table in a separate
 752   // section, as in -function-sections, to facilitate lld's --gc-section.
 753   LSDASection = Ctx->getWasmSection(".rodata.gcc_except_table",
 754                                     SectionKind::getReadOnlyWithRel());
 755
 756   // TODO: Define more sections.
 757 }
 758
 759 void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple, bool PIC,
 760                                             MCContext &ctx,
 761                                             bool LargeCodeModel) {
 762   PositionIndependent = PIC;
 763   Ctx = &ctx;
 764
 765   // Common.
 766   CommDirectiveSupportsAlignment = true;
 767   SupportsWeakOmittedEHFrame = true;
 768   SupportsCompactUnwindWithoutEHFrame = false;
 769   OmitDwarfIfHaveCompactUnwind = false;
 770
 771   FDECFIEncoding = dwarf::DW_EH_PE_absptr;
 772
 773   CompactUnwindDwarfEHFrameOnly = 0;
 774
 775   EHFrameSection = nullptr;             // Created on demand.
 776   CompactUnwindSection = nullptr;       // Used only by selected targets.
 777   DwarfAccelNamesSection = nullptr;     // Used only by selected targets.
 778   DwarfAccelObjCSection = nullptr;      // Used only by selected targets.
 779   DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
 780   DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
 781
 782   TT = TheTriple;
 783
 784   switch (TT.getObjectFormat()) {
 785   case Triple::MachO:
 786     Env = IsMachO;
 787     initMachOMCObjectFileInfo(TT);
 788     break;
 789   case Triple::COFF:
 790     if (!TT.isOSWindows())
 791       report_fatal_error(
 792           "Cannot initialize MC for non-Windows COFF object files.");
 793
 794     Env = IsCOFF;
 795     initCOFFMCObjectFileInfo(TT);
 796     break;
 797   case Triple::ELF:
 798     Env = IsELF;
 799     initELFMCObjectFileInfo(TT, LargeCodeModel);
 800     break;
 801   case Triple::Wasm:
 802     Env = IsWasm;
 803     initWasmMCObjectFileInfo(TT);
 804     break;
 805   case Triple::UnknownObjectFormat:
 806     report_fatal_error("Cannot initialize MC for unknown object file format.");
 807     break;
 808   }
 809 }
 810
 811 MCSection *MCObjectFileInfo::getDwarfComdatSection(const char *Name,
 812                                                    uint64_t Hash) const {
 813   switch (TT.getObjectFormat()) {
 814   case Triple::ELF:
 815     return Ctx->getELFSection(Name, ELF::SHT_PROGBITS, ELF::SHF_GROUP, 0,
 816                               utostr(Hash));
 817   case Triple::MachO:
 818   case Triple::COFF:
 819   case Triple::Wasm:
 820   case Triple::UnknownObjectFormat:
 821     report_fatal_error("Cannot get DWARF comdat section for this object file "
 822                        "format: not implemented.");
 823     break;
 824   }
 825   llvm_unreachable("Unknown ObjectFormatType");
 826 }
 827
 828 MCSection *
 829 MCObjectFileInfo::getStackSizesSection(const MCSection &TextSec) const {
 830   if (Env != IsELF)
 831     return StackSizesSection;
 832
 833   const MCSectionELF &ElfSec = static_cast<const MCSectionELF &>(TextSec);
 834   unsigned Flags = ELF::SHF_LINK_ORDER;
 835   StringRef GroupName;
 836   if (const MCSymbol *Group = ElfSec.getGroup()) {
 837     GroupName = Group->getName();
 838     Flags |= ELF::SHF_GROUP;
 839   }
 840
 841   const MCSymbol *Link = TextSec.getBeginSymbol();
 842   auto It = StackSizesUniquing.insert({Link, StackSizesUniquing.size()});
 843   unsigned UniqueID = It.first->second;
 844
 845   return Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, Flags, 0,
 846                             GroupName, UniqueID, cast<MCSymbolELF>(Link));
 847 }