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