lib/MC/MCObjectFileInfo.cpp

   1 //===-- MCObjectFileInfo.cpp - Object File Information --------------------===//
   2 //
   3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
   4 // See https://llvm.org/LICENSE.txt for license information.
   5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
   6 //
   7 //===----------------------------------------------------------------------===//
   8
   9 #include "llvm/MC/MCObjectFileInfo.h"
  10 #include "llvm/ADT/StringExtras.h"
  11 #include "llvm/ADT/Triple.h"
  12 #include "llvm/BinaryFormat/COFF.h"
  13 #include "llvm/BinaryFormat/ELF.h"
  14 #include "llvm/MC/MCAsmInfo.h"
  15 #include "llvm/MC/MCContext.h"
  16 #include "llvm/MC/MCSection.h"
  17 #include "llvm/MC/MCSectionCOFF.h"
  18 #include "llvm/MC/MCSectionELF.h"
  19 #include "llvm/MC/MCSectionMachO.h"
  20 #include "llvm/MC/MCSectionWasm.h"
  21 #include "llvm/MC/MCSectionXCOFF.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 || T.getArch() == Triple::aarch64_32)
  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() &&
  61       (T.getArch() == Triple::aarch64 || T.getArch() == Triple::aarch64_32))
  62     SupportsCompactUnwindWithoutEHFrame = true;
  63
  64   if (T.isWatchABI())
  65     OmitDwarfIfHaveCompactUnwind = true;
  66
  67   FDECFIEncoding = dwarf::DW_EH_PE_pcrel;
  68
  69   // .comm doesn't support alignment before Leopard.
  70   if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
  71     CommDirectiveSupportsAlignment = false;
  72
  73   TextSection // .text
  74     = Ctx->getMachOSection("__TEXT", "__text",
  75                            MachO::S_ATTR_PURE_INSTRUCTIONS,
  76                            SectionKind::getText());
  77   DataSection // .data
  78       = Ctx->getMachOSection("__DATA", "__data", 0, SectionKind::getData());
  79
  80   // BSSSection might not be expected initialized on msvc.
  81   BSSSection = nullptr;
  82
  83   TLSDataSection // .tdata
  84       = Ctx->getMachOSection("__DATA", "__thread_data",
  85                              MachO::S_THREAD_LOCAL_REGULAR,
  86                              SectionKind::getData());
  87   TLSBSSSection // .tbss
  88     = Ctx->getMachOSection("__DATA", "__thread_bss",
  89                            MachO::S_THREAD_LOCAL_ZEROFILL,
  90                            SectionKind::getThreadBSS());
  91
  92   // TODO: Verify datarel below.
  93   TLSTLVSection // .tlv
  94       = Ctx->getMachOSection("__DATA", "__thread_vars",
  95                              MachO::S_THREAD_LOCAL_VARIABLES,
  96                              SectionKind::getData());
  97
  98   TLSThreadInitSection = Ctx->getMachOSection(
  99       "__DATA", "__thread_init", MachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
 100       SectionKind::getData());
 101
 102   CStringSection // .cstring
 103     = Ctx->getMachOSection("__TEXT", "__cstring",
 104                            MachO::S_CSTRING_LITERALS,
 105                            SectionKind::getMergeable1ByteCString());
 106   UStringSection
 107     = Ctx->getMachOSection("__TEXT","__ustring", 0,
 108                            SectionKind::getMergeable2ByteCString());
 109   FourByteConstantSection // .literal4
 110     = Ctx->getMachOSection("__TEXT", "__literal4",
 111                            MachO::S_4BYTE_LITERALS,
 112                            SectionKind::getMergeableConst4());
 113   EightByteConstantSection // .literal8
 114     = Ctx->getMachOSection("__TEXT", "__literal8",
 115                            MachO::S_8BYTE_LITERALS,
 116                            SectionKind::getMergeableConst8());
 117
 118   SixteenByteConstantSection // .literal16
 119       = Ctx->getMachOSection("__TEXT", "__literal16",
 120                              MachO::S_16BYTE_LITERALS,
 121                              SectionKind::getMergeableConst16());
 122
 123   ReadOnlySection  // .const
 124     = Ctx->getMachOSection("__TEXT", "__const", 0,
 125                            SectionKind::getReadOnly());
 126
 127   // If the target is not powerpc, map the coal sections to the non-coal
 128   // sections.
 129   //
 130   // "__TEXT/__textcoal_nt" => section "__TEXT/__text"
 131   // "__TEXT/__const_coal"  => section "__TEXT/__const"
 132   // "__DATA/__datacoal_nt" => section "__DATA/__data"
 133   Triple::ArchType ArchTy = T.getArch();
 134
 135   ConstDataSection  // .const_data
 136     = Ctx->getMachOSection("__DATA", "__const", 0,
 137                            SectionKind::getReadOnlyWithRel());
 138
 139   if (ArchTy == Triple::ppc || ArchTy == Triple::ppc64) {
 140     TextCoalSection
 141       = Ctx->getMachOSection("__TEXT", "__textcoal_nt",
 142                              MachO::S_COALESCED |
 143                              MachO::S_ATTR_PURE_INSTRUCTIONS,
 144                              SectionKind::getText());
 145     ConstTextCoalSection
 146       = Ctx->getMachOSection("__TEXT", "__const_coal",
 147                              MachO::S_COALESCED,
 148                              SectionKind::getReadOnly());
 149     DataCoalSection = Ctx->getMachOSection(
 150         "__DATA", "__datacoal_nt", MachO::S_COALESCED, SectionKind::getData());
 151     ConstDataCoalSection = DataCoalSection;
 152   } else {
 153     TextCoalSection = TextSection;
 154     ConstTextCoalSection = ReadOnlySection;
 155     DataCoalSection = DataSection;
 156     ConstDataCoalSection = ConstDataSection;
 157   }
 158
 159   DataCommonSection
 160     = Ctx->getMachOSection("__DATA","__common",
 161                            MachO::S_ZEROFILL,
 162                            SectionKind::getBSS());
 163   DataBSSSection
 164     = Ctx->getMachOSection("__DATA","__bss", MachO::S_ZEROFILL,
 165                            SectionKind::getBSS());
 166
 167
 168   LazySymbolPointerSection
 169     = Ctx->getMachOSection("__DATA", "__la_symbol_ptr",
 170                            MachO::S_LAZY_SYMBOL_POINTERS,
 171                            SectionKind::getMetadata());
 172   NonLazySymbolPointerSection
 173     = Ctx->getMachOSection("__DATA", "__nl_symbol_ptr",
 174                            MachO::S_NON_LAZY_SYMBOL_POINTERS,
 175                            SectionKind::getMetadata());
 176
 177   ThreadLocalPointerSection
 178     = Ctx->getMachOSection("__DATA", "__thread_ptr",
 179                            MachO::S_THREAD_LOCAL_VARIABLE_POINTERS,
 180                            SectionKind::getMetadata());
 181
 182   // Exception Handling.
 183   LSDASection = Ctx->getMachOSection("__TEXT", "__gcc_except_tab", 0,
 184                                      SectionKind::getReadOnlyWithRel());
 185
 186   COFFDebugSymbolsSection = nullptr;
 187   COFFDebugTypesSection = nullptr;
 188   COFFGlobalTypeHashesSection = nullptr;
 189
 190   if (useCompactUnwind(T)) {
 191     CompactUnwindSection =
 192         Ctx->getMachOSection("__LD", "__compact_unwind", MachO::S_ATTR_DEBUG,
 193                              SectionKind::getReadOnly());
 194
 195     if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86)
 196       CompactUnwindDwarfEHFrameOnly = 0x04000000;  // UNWIND_X86_64_MODE_DWARF
 197     else if (T.getArch() == Triple::aarch64 || T.getArch() == Triple::aarch64_32)
 198       CompactUnwindDwarfEHFrameOnly = 0x03000000;  // UNWIND_ARM64_MODE_DWARF
 199     else if (T.getArch() == Triple::arm || T.getArch() == Triple::thumb)
 200       CompactUnwindDwarfEHFrameOnly = 0x04000000;  // UNWIND_ARM_MODE_DWARF
 201   }
 202
 203   // Debug Information.
 204   DwarfDebugNamesSection =
 205       Ctx->getMachOSection("__DWARF", "__debug_names", MachO::S_ATTR_DEBUG,
 206                            SectionKind::getMetadata(), "debug_names_begin");
 207   DwarfAccelNamesSection =
 208       Ctx->getMachOSection("__DWARF", "__apple_names", MachO::S_ATTR_DEBUG,
 209                            SectionKind::getMetadata(), "names_begin");
 210   DwarfAccelObjCSection =
 211       Ctx->getMachOSection("__DWARF", "__apple_objc", MachO::S_ATTR_DEBUG,
 212                            SectionKind::getMetadata(), "objc_begin");
 213   // 16 character section limit...
 214   DwarfAccelNamespaceSection =
 215       Ctx->getMachOSection("__DWARF", "__apple_namespac", MachO::S_ATTR_DEBUG,
 216                            SectionKind::getMetadata(), "namespac_begin");
 217   DwarfAccelTypesSection =
 218       Ctx->getMachOSection("__DWARF", "__apple_types", MachO::S_ATTR_DEBUG,
 219                            SectionKind::getMetadata(), "types_begin");
 220
 221   DwarfSwiftASTSection =
 222       Ctx->getMachOSection("__DWARF", "__swift_ast", MachO::S_ATTR_DEBUG,
 223                            SectionKind::getMetadata());
 224
 225   DwarfAbbrevSection =
 226       Ctx->getMachOSection("__DWARF", "__debug_abbrev", MachO::S_ATTR_DEBUG,
 227                            SectionKind::getMetadata(), "section_abbrev");
 228   DwarfInfoSection =
 229       Ctx->getMachOSection("__DWARF", "__debug_info", MachO::S_ATTR_DEBUG,
 230                            SectionKind::getMetadata(), "section_info");
 231   DwarfLineSection =
 232       Ctx->getMachOSection("__DWARF", "__debug_line", MachO::S_ATTR_DEBUG,
 233                            SectionKind::getMetadata(), "section_line");
 234   DwarfLineStrSection =
 235       Ctx->getMachOSection("__DWARF", "__debug_line_str", MachO::S_ATTR_DEBUG,
 236                            SectionKind::getMetadata(), "section_line_str");
 237   DwarfFrameSection =
 238       Ctx->getMachOSection("__DWARF", "__debug_frame", MachO::S_ATTR_DEBUG,
 239                            SectionKind::getMetadata());
 240   DwarfPubNamesSection =
 241       Ctx->getMachOSection("__DWARF", "__debug_pubnames", MachO::S_ATTR_DEBUG,
 242                            SectionKind::getMetadata());
 243   DwarfPubTypesSection =
 244       Ctx->getMachOSection("__DWARF", "__debug_pubtypes", MachO::S_ATTR_DEBUG,
 245                            SectionKind::getMetadata());
 246   DwarfGnuPubNamesSection =
 247       Ctx->getMachOSection("__DWARF", "__debug_gnu_pubn", MachO::S_ATTR_DEBUG,
 248                            SectionKind::getMetadata());
 249   DwarfGnuPubTypesSection =
 250       Ctx->getMachOSection("__DWARF", "__debug_gnu_pubt", MachO::S_ATTR_DEBUG,
 251                            SectionKind::getMetadata());
 252   DwarfStrSection =
 253       Ctx->getMachOSection("__DWARF", "__debug_str", MachO::S_ATTR_DEBUG,
 254                            SectionKind::getMetadata(), "info_string");
 255   DwarfStrOffSection =
 256       Ctx->getMachOSection("__DWARF", "__debug_str_offs", MachO::S_ATTR_DEBUG,
 257                            SectionKind::getMetadata(), "section_str_off");
 258   DwarfAddrSection =
 259       Ctx->getMachOSection("__DWARF", "__debug_addr", MachO::S_ATTR_DEBUG,
 260                            SectionKind::getMetadata(), "section_info");
 261   DwarfLocSection =
 262       Ctx->getMachOSection("__DWARF", "__debug_loc", MachO::S_ATTR_DEBUG,
 263                            SectionKind::getMetadata(), "section_debug_loc");
 264   DwarfLoclistsSection =
 265       Ctx->getMachOSection("__DWARF", "__debug_loclists", MachO::S_ATTR_DEBUG,
 266                            SectionKind::getMetadata(), "section_debug_loc");
 267
 268   DwarfARangesSection =
 269       Ctx->getMachOSection("__DWARF", "__debug_aranges", MachO::S_ATTR_DEBUG,
 270                            SectionKind::getMetadata());
 271   DwarfRangesSection =
 272       Ctx->getMachOSection("__DWARF", "__debug_ranges", MachO::S_ATTR_DEBUG,
 273                            SectionKind::getMetadata(), "debug_range");
 274   DwarfRnglistsSection =
 275       Ctx->getMachOSection("__DWARF", "__debug_rnglists", MachO::S_ATTR_DEBUG,
 276                            SectionKind::getMetadata(), "debug_range");
 277   DwarfMacinfoSection =
 278       Ctx->getMachOSection("__DWARF", "__debug_macinfo", MachO::S_ATTR_DEBUG,
 279                            SectionKind::getMetadata(), "debug_macinfo");
 280   DwarfDebugInlineSection =
 281       Ctx->getMachOSection("__DWARF", "__debug_inlined", MachO::S_ATTR_DEBUG,
 282                            SectionKind::getMetadata());
 283   DwarfCUIndexSection =
 284       Ctx->getMachOSection("__DWARF", "__debug_cu_index", MachO::S_ATTR_DEBUG,
 285                            SectionKind::getMetadata());
 286   DwarfTUIndexSection =
 287       Ctx->getMachOSection("__DWARF", "__debug_tu_index", MachO::S_ATTR_DEBUG,
 288                            SectionKind::getMetadata());
 289   StackMapSection = Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps",
 290                                          0, SectionKind::getMetadata());
 291
 292   FaultMapSection = Ctx->getMachOSection("__LLVM_FAULTMAPS", "__llvm_faultmaps",
 293                                          0, SectionKind::getMetadata());
 294
 295   RemarksSection = Ctx->getMachOSection(
 296       "__LLVM", "__remarks", MachO::S_ATTR_DEBUG, SectionKind::getMetadata());
 297
 298   TLSExtraDataSection = TLSTLVSection;
 299 }
 300
 301 void MCObjectFileInfo::initELFMCObjectFileInfo(const Triple &T, bool Large) {
 302   switch (T.getArch()) {
 303   case Triple::mips:
 304   case Triple::mipsel:
 305   case Triple::mips64:
 306   case Triple::mips64el:
 307     FDECFIEncoding = Ctx->getAsmInfo()->getCodePointerSize() == 4
 308                          ? dwarf::DW_EH_PE_sdata4
 309                          : dwarf::DW_EH_PE_sdata8;
 310     break;
 311   case Triple::ppc64:
 312   case Triple::ppc64le:
 313   case Triple::x86_64:
 314     FDECFIEncoding = dwarf::DW_EH_PE_pcrel |
 315                      (Large ? dwarf::DW_EH_PE_sdata8 : dwarf::DW_EH_PE_sdata4);
 316     break;
 317   case Triple::bpfel:
 318   case Triple::bpfeb:
 319     FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
 320     break;
 321   case Triple::hexagon:
 322     FDECFIEncoding =
 323         PositionIndependent ? dwarf::DW_EH_PE_pcrel : dwarf::DW_EH_PE_absptr;
 324     break;
 325   default:
 326     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
 327     break;
 328   }
 329
 330   unsigned EHSectionType = T.getArch() == Triple::x86_64
 331                                ? ELF::SHT_X86_64_UNWIND
 332                                : ELF::SHT_PROGBITS;
 333
 334   // Solaris requires different flags for .eh_frame to seemingly every other
 335   // platform.
 336   unsigned EHSectionFlags = ELF::SHF_ALLOC;
 337   if (T.isOSSolaris() && T.getArch() != Triple::x86_64)
 338     EHSectionFlags |= ELF::SHF_WRITE;
 339
 340   // ELF
 341   BSSSection = Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
 342                                   ELF::SHF_WRITE | ELF::SHF_ALLOC);
 343
 344   TextSection = Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
 345                                    ELF::SHF_EXECINSTR | ELF::SHF_ALLOC);
 346
 347   DataSection = Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
 348                                    ELF::SHF_WRITE | ELF::SHF_ALLOC);
 349
 350   ReadOnlySection =
 351       Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
 352
 353   TLSDataSection =
 354       Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
 355                          ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
 356
 357   TLSBSSSection = Ctx->getELFSection(
 358       ".tbss", ELF::SHT_NOBITS, ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
 359
 360   DataRelROSection = Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
 361                                         ELF::SHF_ALLOC | ELF::SHF_WRITE);
 362
 363   MergeableConst4Section =
 364       Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
 365                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 4, "");
 366
 367   MergeableConst8Section =
 368       Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
 369                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 8, "");
 370
 371   MergeableConst16Section =
 372       Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
 373                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 16, "");
 374
 375   MergeableConst32Section =
 376       Ctx->getELFSection(".rodata.cst32", ELF::SHT_PROGBITS,
 377                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 32, "");
 378
 379   // Exception Handling Sections.
 380
 381   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
 382   // it contains relocatable pointers.  In PIC mode, this is probably a big
 383   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
 384   // adjusted or this should be a data section.
 385   LSDASection = Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
 386                                    ELF::SHF_ALLOC);
 387
 388   COFFDebugSymbolsSection = nullptr;
 389   COFFDebugTypesSection = nullptr;
 390
 391   unsigned DebugSecType = ELF::SHT_PROGBITS;
 392
 393   // MIPS .debug_* sections should have SHT_MIPS_DWARF section type
 394   // to distinguish among sections contain DWARF and ECOFF debug formats.
 395   // Sections with ECOFF debug format are obsoleted and marked by SHT_PROGBITS.
 396   if (T.isMIPS())
 397     DebugSecType = ELF::SHT_MIPS_DWARF;
 398
 399   // Debug Info Sections.
 400   DwarfAbbrevSection =
 401       Ctx->getELFSection(".debug_abbrev", DebugSecType, 0);
 402   DwarfInfoSection = Ctx->getELFSection(".debug_info", DebugSecType, 0);
 403   DwarfLineSection = Ctx->getELFSection(".debug_line", DebugSecType, 0);
 404   DwarfLineStrSection =
 405       Ctx->getELFSection(".debug_line_str", DebugSecType,
 406                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
 407   DwarfFrameSection = Ctx->getELFSection(".debug_frame", DebugSecType, 0);
 408   DwarfPubNamesSection =
 409       Ctx->getELFSection(".debug_pubnames", DebugSecType, 0);
 410   DwarfPubTypesSection =
 411       Ctx->getELFSection(".debug_pubtypes", DebugSecType, 0);
 412   DwarfGnuPubNamesSection =
 413       Ctx->getELFSection(".debug_gnu_pubnames", DebugSecType, 0);
 414   DwarfGnuPubTypesSection =
 415       Ctx->getELFSection(".debug_gnu_pubtypes", DebugSecType, 0);
 416   DwarfStrSection =
 417       Ctx->getELFSection(".debug_str", DebugSecType,
 418                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
 419   DwarfLocSection = Ctx->getELFSection(".debug_loc", DebugSecType, 0);
 420   DwarfARangesSection =
 421       Ctx->getELFSection(".debug_aranges", DebugSecType, 0);
 422   DwarfRangesSection =
 423       Ctx->getELFSection(".debug_ranges", DebugSecType, 0);
 424   DwarfMacinfoSection =
 425       Ctx->getELFSection(".debug_macinfo", DebugSecType, 0);
 426
 427   // DWARF5 Experimental Debug Info
 428
 429   // Accelerator Tables
 430   DwarfDebugNamesSection =
 431       Ctx->getELFSection(".debug_names", ELF::SHT_PROGBITS, 0);
 432   DwarfAccelNamesSection =
 433       Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0);
 434   DwarfAccelObjCSection =
 435       Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0);
 436   DwarfAccelNamespaceSection =
 437       Ctx->getELFSection(".apple_namespaces", ELF::SHT_PROGBITS, 0);
 438   DwarfAccelTypesSection =
 439       Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0);
 440
 441   // String Offset and Address Sections
 442   DwarfStrOffSection =
 443       Ctx->getELFSection(".debug_str_offsets", DebugSecType, 0);
 444   DwarfAddrSection = Ctx->getELFSection(".debug_addr", DebugSecType, 0);
 445   DwarfRnglistsSection = Ctx->getELFSection(".debug_rnglists", DebugSecType, 0);
 446   DwarfLoclistsSection = Ctx->getELFSection(".debug_loclists", DebugSecType, 0);
 447
 448   // Fission Sections
 449   DwarfInfoDWOSection =
 450       Ctx->getELFSection(".debug_info.dwo", DebugSecType, ELF::SHF_EXCLUDE);
 451   DwarfTypesDWOSection =
 452       Ctx->getELFSection(".debug_types.dwo", DebugSecType, ELF::SHF_EXCLUDE);
 453   DwarfAbbrevDWOSection =
 454       Ctx->getELFSection(".debug_abbrev.dwo", DebugSecType, ELF::SHF_EXCLUDE);
 455   DwarfStrDWOSection = Ctx->getELFSection(
 456       ".debug_str.dwo", DebugSecType,
 457       ELF::SHF_MERGE | ELF::SHF_STRINGS | ELF::SHF_EXCLUDE, 1, "");
 458   DwarfLineDWOSection =
 459       Ctx->getELFSection(".debug_line.dwo", DebugSecType, ELF::SHF_EXCLUDE);
 460   DwarfLocDWOSection =
 461       Ctx->getELFSection(".debug_loc.dwo", DebugSecType, ELF::SHF_EXCLUDE);
 462   DwarfStrOffDWOSection = Ctx->getELFSection(".debug_str_offsets.dwo",
 463                                              DebugSecType, ELF::SHF_EXCLUDE);
 464   DwarfRnglistsDWOSection =
 465       Ctx->getELFSection(".debug_rnglists.dwo", DebugSecType, ELF::SHF_EXCLUDE);
 466
 467   // DWP Sections
 468   DwarfCUIndexSection =
 469       Ctx->getELFSection(".debug_cu_index", DebugSecType, 0);
 470   DwarfTUIndexSection =
 471       Ctx->getELFSection(".debug_tu_index", DebugSecType, 0);
 472
 473   StackMapSection =
 474       Ctx->getELFSection(".llvm_stackmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
 475
 476   FaultMapSection =
 477       Ctx->getELFSection(".llvm_faultmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
 478
 479   EHFrameSection =
 480       Ctx->getELFSection(".eh_frame", EHSectionType, EHSectionFlags);
 481
 482   StackSizesSection = Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, 0);
 483
 484   RemarksSection =
 485       Ctx->getELFSection(".remarks", ELF::SHT_PROGBITS, ELF::SHF_EXCLUDE);
 486 }
 487
 488 void MCObjectFileInfo::initCOFFMCObjectFileInfo(const Triple &T) {
 489   EHFrameSection =
 490       Ctx->getCOFFSection(".eh_frame", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 491                                            COFF::IMAGE_SCN_MEM_READ,
 492                           SectionKind::getData());
 493
 494   // Set the `IMAGE_SCN_MEM_16BIT` flag when compiling for thumb mode.  This is
 495   // used to indicate to the linker that the text segment contains thumb instructions
 496   // and to set the ISA selection bit for calls accordingly.
 497   const bool IsThumb = T.getArch() == Triple::thumb;
 498
 499   CommDirectiveSupportsAlignment = true;
 500
 501   // COFF
 502   BSSSection = Ctx->getCOFFSection(
 503       ".bss", COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
 504                   COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
 505       SectionKind::getBSS());
 506   TextSection = Ctx->getCOFFSection(
 507       ".text",
 508       (IsThumb ? COFF::IMAGE_SCN_MEM_16BIT : (COFF::SectionCharacteristics)0) |
 509           COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE |
 510           COFF::IMAGE_SCN_MEM_READ,
 511       SectionKind::getText());
 512   DataSection = Ctx->getCOFFSection(
 513       ".data", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
 514                    COFF::IMAGE_SCN_MEM_WRITE,
 515       SectionKind::getData());
 516   ReadOnlySection = Ctx->getCOFFSection(
 517       ".rdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
 518       SectionKind::getReadOnly());
 519
 520   if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::aarch64) {
 521     // On Windows 64 with SEH, the LSDA is emitted into the .xdata section
 522     LSDASection = nullptr;
 523   } else {
 524     LSDASection = Ctx->getCOFFSection(".gcc_except_table",
 525                                       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 526                                           COFF::IMAGE_SCN_MEM_READ,
 527                                       SectionKind::getReadOnly());
 528   }
 529
 530   // Debug info.
 531   COFFDebugSymbolsSection =
 532       Ctx->getCOFFSection(".debug$S", (COFF::IMAGE_SCN_MEM_DISCARDABLE |
 533                                        COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 534                                        COFF::IMAGE_SCN_MEM_READ),
 535                           SectionKind::getMetadata());
 536   COFFDebugTypesSection =
 537       Ctx->getCOFFSection(".debug$T", (COFF::IMAGE_SCN_MEM_DISCARDABLE |
 538                                        COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 539                                        COFF::IMAGE_SCN_MEM_READ),
 540                           SectionKind::getMetadata());
 541   COFFGlobalTypeHashesSection = Ctx->getCOFFSection(
 542       ".debug$H",
 543       (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 544        COFF::IMAGE_SCN_MEM_READ),
 545       SectionKind::getMetadata());
 546
 547   DwarfAbbrevSection = Ctx->getCOFFSection(
 548       ".debug_abbrev",
 549       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 550           COFF::IMAGE_SCN_MEM_READ,
 551       SectionKind::getMetadata(), "section_abbrev");
 552   DwarfInfoSection = Ctx->getCOFFSection(
 553       ".debug_info",
 554       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 555           COFF::IMAGE_SCN_MEM_READ,
 556       SectionKind::getMetadata(), "section_info");
 557   DwarfLineSection = Ctx->getCOFFSection(
 558       ".debug_line",
 559       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 560           COFF::IMAGE_SCN_MEM_READ,
 561       SectionKind::getMetadata(), "section_line");
 562   DwarfLineStrSection = Ctx->getCOFFSection(
 563       ".debug_line_str",
 564       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 565           COFF::IMAGE_SCN_MEM_READ,
 566       SectionKind::getMetadata(), "section_line_str");
 567   DwarfFrameSection = Ctx->getCOFFSection(
 568       ".debug_frame",
 569       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 570           COFF::IMAGE_SCN_MEM_READ,
 571       SectionKind::getMetadata());
 572   DwarfPubNamesSection = Ctx->getCOFFSection(
 573       ".debug_pubnames",
 574       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 575           COFF::IMAGE_SCN_MEM_READ,
 576       SectionKind::getMetadata());
 577   DwarfPubTypesSection = Ctx->getCOFFSection(
 578       ".debug_pubtypes",
 579       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 580           COFF::IMAGE_SCN_MEM_READ,
 581       SectionKind::getMetadata());
 582   DwarfGnuPubNamesSection = Ctx->getCOFFSection(
 583       ".debug_gnu_pubnames",
 584       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 585           COFF::IMAGE_SCN_MEM_READ,
 586       SectionKind::getMetadata());
 587   DwarfGnuPubTypesSection = Ctx->getCOFFSection(
 588       ".debug_gnu_pubtypes",
 589       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 590           COFF::IMAGE_SCN_MEM_READ,
 591       SectionKind::getMetadata());
 592   DwarfStrSection = Ctx->getCOFFSection(
 593       ".debug_str",
 594       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 595           COFF::IMAGE_SCN_MEM_READ,
 596       SectionKind::getMetadata(), "info_string");
 597   DwarfStrOffSection = Ctx->getCOFFSection(
 598       ".debug_str_offsets",
 599       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 600           COFF::IMAGE_SCN_MEM_READ,
 601       SectionKind::getMetadata(), "section_str_off");
 602   DwarfLocSection = Ctx->getCOFFSection(
 603       ".debug_loc",
 604       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 605           COFF::IMAGE_SCN_MEM_READ,
 606       SectionKind::getMetadata(), "section_debug_loc");
 607   DwarfARangesSection = Ctx->getCOFFSection(
 608       ".debug_aranges",
 609       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 610           COFF::IMAGE_SCN_MEM_READ,
 611       SectionKind::getMetadata());
 612   DwarfRangesSection = Ctx->getCOFFSection(
 613       ".debug_ranges",
 614       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 615           COFF::IMAGE_SCN_MEM_READ,
 616       SectionKind::getMetadata(), "debug_range");
 617   DwarfMacinfoSection = Ctx->getCOFFSection(
 618       ".debug_macinfo",
 619       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 620           COFF::IMAGE_SCN_MEM_READ,
 621       SectionKind::getMetadata(), "debug_macinfo");
 622   DwarfInfoDWOSection = Ctx->getCOFFSection(
 623       ".debug_info.dwo",
 624       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 625           COFF::IMAGE_SCN_MEM_READ,
 626       SectionKind::getMetadata(), "section_info_dwo");
 627   DwarfTypesDWOSection = Ctx->getCOFFSection(
 628       ".debug_types.dwo",
 629       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 630           COFF::IMAGE_SCN_MEM_READ,
 631       SectionKind::getMetadata(), "section_types_dwo");
 632   DwarfAbbrevDWOSection = Ctx->getCOFFSection(
 633       ".debug_abbrev.dwo",
 634       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 635           COFF::IMAGE_SCN_MEM_READ,
 636       SectionKind::getMetadata(), "section_abbrev_dwo");
 637   DwarfStrDWOSection = Ctx->getCOFFSection(
 638       ".debug_str.dwo",
 639       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 640           COFF::IMAGE_SCN_MEM_READ,
 641       SectionKind::getMetadata(), "skel_string");
 642   DwarfLineDWOSection = Ctx->getCOFFSection(
 643       ".debug_line.dwo",
 644       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 645           COFF::IMAGE_SCN_MEM_READ,
 646       SectionKind::getMetadata());
 647   DwarfLocDWOSection = Ctx->getCOFFSection(
 648       ".debug_loc.dwo",
 649       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 650           COFF::IMAGE_SCN_MEM_READ,
 651       SectionKind::getMetadata(), "skel_loc");
 652   DwarfStrOffDWOSection = Ctx->getCOFFSection(
 653       ".debug_str_offsets.dwo",
 654       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 655           COFF::IMAGE_SCN_MEM_READ,
 656       SectionKind::getMetadata(), "section_str_off_dwo");
 657   DwarfAddrSection = Ctx->getCOFFSection(
 658       ".debug_addr",
 659       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 660           COFF::IMAGE_SCN_MEM_READ,
 661       SectionKind::getMetadata(), "addr_sec");
 662   DwarfCUIndexSection = Ctx->getCOFFSection(
 663       ".debug_cu_index",
 664       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 665           COFF::IMAGE_SCN_MEM_READ,
 666       SectionKind::getMetadata());
 667   DwarfTUIndexSection = Ctx->getCOFFSection(
 668       ".debug_tu_index",
 669       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 670           COFF::IMAGE_SCN_MEM_READ,
 671       SectionKind::getMetadata());
 672   DwarfDebugNamesSection = Ctx->getCOFFSection(
 673       ".debug_names",
 674       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 675           COFF::IMAGE_SCN_MEM_READ,
 676       SectionKind::getMetadata(), "debug_names_begin");
 677   DwarfAccelNamesSection = Ctx->getCOFFSection(
 678       ".apple_names",
 679       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 680           COFF::IMAGE_SCN_MEM_READ,
 681       SectionKind::getMetadata(), "names_begin");
 682   DwarfAccelNamespaceSection = Ctx->getCOFFSection(
 683       ".apple_namespaces",
 684       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 685           COFF::IMAGE_SCN_MEM_READ,
 686       SectionKind::getMetadata(), "namespac_begin");
 687   DwarfAccelTypesSection = Ctx->getCOFFSection(
 688       ".apple_types",
 689       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 690           COFF::IMAGE_SCN_MEM_READ,
 691       SectionKind::getMetadata(), "types_begin");
 692   DwarfAccelObjCSection = Ctx->getCOFFSection(
 693       ".apple_objc",
 694       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 695           COFF::IMAGE_SCN_MEM_READ,
 696       SectionKind::getMetadata(), "objc_begin");
 697
 698   DrectveSection = Ctx->getCOFFSection(
 699       ".drectve", COFF::IMAGE_SCN_LNK_INFO | COFF::IMAGE_SCN_LNK_REMOVE,
 700       SectionKind::getMetadata());
 701
 702   PDataSection = Ctx->getCOFFSection(
 703       ".pdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
 704       SectionKind::getData());
 705
 706   XDataSection = Ctx->getCOFFSection(
 707       ".xdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
 708       SectionKind::getData());
 709
 710   SXDataSection = Ctx->getCOFFSection(".sxdata", COFF::IMAGE_SCN_LNK_INFO,
 711                                       SectionKind::getMetadata());
 712
 713   GFIDsSection = Ctx->getCOFFSection(".gfids$y",
 714                                      COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 715                                          COFF::IMAGE_SCN_MEM_READ,
 716                                      SectionKind::getMetadata());
 717
 718   TLSDataSection = Ctx->getCOFFSection(
 719       ".tls$", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
 720                    COFF::IMAGE_SCN_MEM_WRITE,
 721       SectionKind::getData());
 722
 723   StackMapSection = Ctx->getCOFFSection(".llvm_stackmaps",
 724                                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
 725                                             COFF::IMAGE_SCN_MEM_READ,
 726                                         SectionKind::getReadOnly());
 727 }
 728
 729 void MCObjectFileInfo::initWasmMCObjectFileInfo(const Triple &T) {
 730   TextSection = Ctx->getWasmSection(".text", SectionKind::getText());
 731   DataSection = Ctx->getWasmSection(".data", SectionKind::getData());
 732
 733   DwarfLineSection =
 734       Ctx->getWasmSection(".debug_line", SectionKind::getMetadata());
 735   DwarfLineStrSection =
 736       Ctx->getWasmSection(".debug_line_str", SectionKind::getMetadata());
 737   DwarfStrSection =
 738       Ctx->getWasmSection(".debug_str", SectionKind::getMetadata());
 739   DwarfLocSection =
 740       Ctx->getWasmSection(".debug_loc", SectionKind::getMetadata());
 741   DwarfAbbrevSection =
 742       Ctx->getWasmSection(".debug_abbrev", SectionKind::getMetadata());
 743   DwarfARangesSection = Ctx->getWasmSection(".debug_aranges", SectionKind::getMetadata());
 744   DwarfRangesSection =
 745       Ctx->getWasmSection(".debug_ranges", SectionKind::getMetadata());
 746   DwarfMacinfoSection =
 747       Ctx->getWasmSection(".debug_macinfo", SectionKind::getMetadata());
 748   DwarfAddrSection = Ctx->getWasmSection(".debug_addr", SectionKind::getMetadata());
 749   DwarfCUIndexSection = Ctx->getWasmSection(".debug_cu_index", SectionKind::getMetadata());
 750   DwarfTUIndexSection = Ctx->getWasmSection(".debug_tu_index", SectionKind::getMetadata());
 751   DwarfInfoSection =
 752       Ctx->getWasmSection(".debug_info", SectionKind::getMetadata());
 753   DwarfFrameSection = Ctx->getWasmSection(".debug_frame", SectionKind::getMetadata());
 754   DwarfPubNamesSection = Ctx->getWasmSection(".debug_pubnames", SectionKind::getMetadata());
 755   DwarfPubTypesSection = Ctx->getWasmSection(".debug_pubtypes", SectionKind::getMetadata());
 756
 757   // Wasm use data section for LSDA.
 758   // TODO Consider putting each function's exception table in a separate
 759   // section, as in -function-sections, to facilitate lld's --gc-section.
 760   LSDASection = Ctx->getWasmSection(".rodata.gcc_except_table",
 761                                     SectionKind::getReadOnlyWithRel());
 762
 763   // TODO: Define more sections.
 764 }
 765
 766 void MCObjectFileInfo::initXCOFFMCObjectFileInfo(const Triple &T) {
 767   // The default csect for program code. Functions without a specified section
 768   // get placed into this csect. The choice of csect name is not a property of
 769   // the ABI or object file format. For example, the XL compiler uses an unnamed
 770   // csect for program code.
 771   TextSection = Ctx->getXCOFFSection(
 772       ".text", XCOFF::StorageMappingClass::XMC_PR, XCOFF::XTY_SD,
 773       XCOFF::C_HIDEXT, SectionKind::getText());
 774
 775   DataSection = Ctx->getXCOFFSection(
 776       ".data", XCOFF::StorageMappingClass::XMC_RW, XCOFF::XTY_SD,
 777       XCOFF::C_HIDEXT, SectionKind::getData());
 778 }
 779
 780 void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple, bool PIC,
 781                                             MCContext &ctx,
 782                                             bool LargeCodeModel) {
 783   PositionIndependent = PIC;
 784   Ctx = &ctx;
 785
 786   // Common.
 787   CommDirectiveSupportsAlignment = true;
 788   SupportsWeakOmittedEHFrame = true;
 789   SupportsCompactUnwindWithoutEHFrame = false;
 790   OmitDwarfIfHaveCompactUnwind = false;
 791
 792   FDECFIEncoding = dwarf::DW_EH_PE_absptr;
 793
 794   CompactUnwindDwarfEHFrameOnly = 0;
 795
 796   EHFrameSection = nullptr;             // Created on demand.
 797   CompactUnwindSection = nullptr;       // Used only by selected targets.
 798   DwarfAccelNamesSection = nullptr;     // Used only by selected targets.
 799   DwarfAccelObjCSection = nullptr;      // Used only by selected targets.
 800   DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
 801   DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
 802
 803   TT = TheTriple;
 804
 805   switch (TT.getObjectFormat()) {
 806   case Triple::MachO:
 807     Env = IsMachO;
 808     initMachOMCObjectFileInfo(TT);
 809     break;
 810   case Triple::COFF:
 811     if (!TT.isOSWindows())
 812       report_fatal_error(
 813           "Cannot initialize MC for non-Windows COFF object files.");
 814
 815     Env = IsCOFF;
 816     initCOFFMCObjectFileInfo(TT);
 817     break;
 818   case Triple::ELF:
 819     Env = IsELF;
 820     initELFMCObjectFileInfo(TT, LargeCodeModel);
 821     break;
 822   case Triple::Wasm:
 823     Env = IsWasm;
 824     initWasmMCObjectFileInfo(TT);
 825     break;
 826   case Triple::XCOFF:
 827     Env = IsXCOFF;
 828     initXCOFFMCObjectFileInfo(TT);
 829     break;
 830   case Triple::UnknownObjectFormat:
 831     report_fatal_error("Cannot initialize MC for unknown object file format.");
 832     break;
 833   }
 834 }
 835
 836 MCSection *MCObjectFileInfo::getDwarfComdatSection(const char *Name,
 837                                                    uint64_t Hash) const {
 838   switch (TT.getObjectFormat()) {
 839   case Triple::ELF:
 840     return Ctx->getELFSection(Name, ELF::SHT_PROGBITS, ELF::SHF_GROUP, 0,
 841                               utostr(Hash));
 842   case Triple::MachO:
 843   case Triple::COFF:
 844   case Triple::Wasm:
 845   case Triple::XCOFF:
 846   case Triple::UnknownObjectFormat:
 847     report_fatal_error("Cannot get DWARF comdat section for this object file "
 848                        "format: not implemented.");
 849     break;
 850   }
 851   llvm_unreachable("Unknown ObjectFormatType");
 852 }
 853
 854 MCSection *
 855 MCObjectFileInfo::getStackSizesSection(const MCSection &TextSec) const {
 856   if (Env != IsELF)
 857     return StackSizesSection;
 858
 859   const MCSectionELF &ElfSec = static_cast<const MCSectionELF &>(TextSec);
 860   unsigned Flags = ELF::SHF_LINK_ORDER;
 861   StringRef GroupName;
 862   if (const MCSymbol *Group = ElfSec.getGroup()) {
 863     GroupName = Group->getName();
 864     Flags |= ELF::SHF_GROUP;
 865   }
 866
 867   const MCSymbol *Link = TextSec.getBeginSymbol();
 868   auto It = StackSizesUniquing.insert({Link, StackSizesUniquing.size()});
 869   unsigned UniqueID = It.first->second;
 870
 871   return Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, Flags, 0,
 872                             GroupName, UniqueID, cast<MCSymbolELF>(Link));
 873 }