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() && T.isX86())
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() &&
60       (T.getArch() == Triple::aarch64 || T.getArch() == Triple::aarch64_32))
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.isX86())
195       CompactUnwindDwarfEHFrameOnly = 0x04000000;  // UNWIND_X86_64_MODE_DWARF
196     else if (T.getArch() == Triple::aarch64 || T.getArch() == Triple::aarch64_32)
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   DwarfMacroSection =
280       Ctx->getMachOSection("__DWARF", "__debug_macro", MachO::S_ATTR_DEBUG,
281                            SectionKind::getMetadata(), "debug_macro");
282   DwarfDebugInlineSection =
283       Ctx->getMachOSection("__DWARF", "__debug_inlined", MachO::S_ATTR_DEBUG,
284                            SectionKind::getMetadata());
285   DwarfCUIndexSection =
286       Ctx->getMachOSection("__DWARF", "__debug_cu_index", MachO::S_ATTR_DEBUG,
287                            SectionKind::getMetadata());
288   DwarfTUIndexSection =
289       Ctx->getMachOSection("__DWARF", "__debug_tu_index", MachO::S_ATTR_DEBUG,
290                            SectionKind::getMetadata());
291   StackMapSection = Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps",
292                                          0, SectionKind::getMetadata());
293 
294   FaultMapSection = Ctx->getMachOSection("__LLVM_FAULTMAPS", "__llvm_faultmaps",
295                                          0, SectionKind::getMetadata());
296 
297   RemarksSection = Ctx->getMachOSection(
298       "__LLVM", "__remarks", MachO::S_ATTR_DEBUG, SectionKind::getMetadata());
299 
300   TLSExtraDataSection = TLSTLVSection;
301 }
302 
303 void MCObjectFileInfo::initELFMCObjectFileInfo(const Triple &T, bool Large) {
304   switch (T.getArch()) {
305   case Triple::mips:
306   case Triple::mipsel:
307   case Triple::mips64:
308   case Triple::mips64el:
309     // We cannot use DW_EH_PE_sdata8 for the large PositionIndependent case
310     // since there is no R_MIPS_PC64 relocation (only a 32-bit version).
311     if (PositionIndependent && !Large)
312       FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
313     else
314       FDECFIEncoding = Ctx->getAsmInfo()->getCodePointerSize() == 4
315                            ? dwarf::DW_EH_PE_sdata4
316                            : dwarf::DW_EH_PE_sdata8;
317     break;
318   case Triple::ppc64:
319   case Triple::ppc64le:
320   case Triple::x86_64:
321     FDECFIEncoding = dwarf::DW_EH_PE_pcrel |
322                      (Large ? dwarf::DW_EH_PE_sdata8 : dwarf::DW_EH_PE_sdata4);
323     break;
324   case Triple::bpfel:
325   case Triple::bpfeb:
326     FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
327     break;
328   case Triple::hexagon:
329     FDECFIEncoding =
330         PositionIndependent ? dwarf::DW_EH_PE_pcrel : dwarf::DW_EH_PE_absptr;
331     break;
332   default:
333     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
334     break;
335   }
336 
337   unsigned EHSectionType = T.getArch() == Triple::x86_64
338                                ? ELF::SHT_X86_64_UNWIND
339                                : ELF::SHT_PROGBITS;
340 
341   // Solaris requires different flags for .eh_frame to seemingly every other
342   // platform.
343   unsigned EHSectionFlags = ELF::SHF_ALLOC;
344   if (T.isOSSolaris() && T.getArch() != Triple::x86_64)
345     EHSectionFlags |= ELF::SHF_WRITE;
346 
347   // ELF
348   BSSSection = Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
349                                   ELF::SHF_WRITE | ELF::SHF_ALLOC);
350 
351   TextSection = Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
352                                    ELF::SHF_EXECINSTR | ELF::SHF_ALLOC);
353 
354   DataSection = Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
355                                    ELF::SHF_WRITE | ELF::SHF_ALLOC);
356 
357   ReadOnlySection =
358       Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
359 
360   TLSDataSection =
361       Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
362                          ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
363 
364   TLSBSSSection = Ctx->getELFSection(
365       ".tbss", ELF::SHT_NOBITS, ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
366 
367   DataRelROSection = Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
368                                         ELF::SHF_ALLOC | ELF::SHF_WRITE);
369 
370   MergeableConst4Section =
371       Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
372                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 4, "");
373 
374   MergeableConst8Section =
375       Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
376                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 8, "");
377 
378   MergeableConst16Section =
379       Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
380                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 16, "");
381 
382   MergeableConst32Section =
383       Ctx->getELFSection(".rodata.cst32", ELF::SHT_PROGBITS,
384                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 32, "");
385 
386   // Exception Handling Sections.
387 
388   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
389   // it contains relocatable pointers.  In PIC mode, this is probably a big
390   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
391   // adjusted or this should be a data section.
392   LSDASection = Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
393                                    ELF::SHF_ALLOC);
394 
395   COFFDebugSymbolsSection = nullptr;
396   COFFDebugTypesSection = nullptr;
397 
398   unsigned DebugSecType = ELF::SHT_PROGBITS;
399 
400   // MIPS .debug_* sections should have SHT_MIPS_DWARF section type
401   // to distinguish among sections contain DWARF and ECOFF debug formats.
402   // Sections with ECOFF debug format are obsoleted and marked by SHT_PROGBITS.
403   if (T.isMIPS())
404     DebugSecType = ELF::SHT_MIPS_DWARF;
405 
406   // Debug Info Sections.
407   DwarfAbbrevSection =
408       Ctx->getELFSection(".debug_abbrev", DebugSecType, 0);
409   DwarfInfoSection = Ctx->getELFSection(".debug_info", DebugSecType, 0);
410   DwarfLineSection = Ctx->getELFSection(".debug_line", DebugSecType, 0);
411   DwarfLineStrSection =
412       Ctx->getELFSection(".debug_line_str", DebugSecType,
413                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
414   DwarfFrameSection = Ctx->getELFSection(".debug_frame", DebugSecType, 0);
415   DwarfPubNamesSection =
416       Ctx->getELFSection(".debug_pubnames", DebugSecType, 0);
417   DwarfPubTypesSection =
418       Ctx->getELFSection(".debug_pubtypes", DebugSecType, 0);
419   DwarfGnuPubNamesSection =
420       Ctx->getELFSection(".debug_gnu_pubnames", DebugSecType, 0);
421   DwarfGnuPubTypesSection =
422       Ctx->getELFSection(".debug_gnu_pubtypes", DebugSecType, 0);
423   DwarfStrSection =
424       Ctx->getELFSection(".debug_str", DebugSecType,
425                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
426   DwarfLocSection = Ctx->getELFSection(".debug_loc", DebugSecType, 0);
427   DwarfARangesSection =
428       Ctx->getELFSection(".debug_aranges", DebugSecType, 0);
429   DwarfRangesSection =
430       Ctx->getELFSection(".debug_ranges", DebugSecType, 0);
431   DwarfMacinfoSection =
432       Ctx->getELFSection(".debug_macinfo", DebugSecType, 0);
433   DwarfMacroSection = Ctx->getELFSection(".debug_macro", DebugSecType, 0);
434 
435   // DWARF5 Experimental Debug Info
436 
437   // Accelerator Tables
438   DwarfDebugNamesSection =
439       Ctx->getELFSection(".debug_names", ELF::SHT_PROGBITS, 0);
440   DwarfAccelNamesSection =
441       Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0);
442   DwarfAccelObjCSection =
443       Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0);
444   DwarfAccelNamespaceSection =
445       Ctx->getELFSection(".apple_namespaces", ELF::SHT_PROGBITS, 0);
446   DwarfAccelTypesSection =
447       Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0);
448 
449   // String Offset and Address Sections
450   DwarfStrOffSection =
451       Ctx->getELFSection(".debug_str_offsets", DebugSecType, 0);
452   DwarfAddrSection = Ctx->getELFSection(".debug_addr", DebugSecType, 0);
453   DwarfRnglistsSection = Ctx->getELFSection(".debug_rnglists", DebugSecType, 0);
454   DwarfLoclistsSection = Ctx->getELFSection(".debug_loclists", DebugSecType, 0);
455 
456   // Fission Sections
457   DwarfInfoDWOSection =
458       Ctx->getELFSection(".debug_info.dwo", DebugSecType, ELF::SHF_EXCLUDE);
459   DwarfTypesDWOSection =
460       Ctx->getELFSection(".debug_types.dwo", DebugSecType, ELF::SHF_EXCLUDE);
461   DwarfAbbrevDWOSection =
462       Ctx->getELFSection(".debug_abbrev.dwo", DebugSecType, ELF::SHF_EXCLUDE);
463   DwarfStrDWOSection = Ctx->getELFSection(
464       ".debug_str.dwo", DebugSecType,
465       ELF::SHF_MERGE | ELF::SHF_STRINGS | ELF::SHF_EXCLUDE, 1, "");
466   DwarfLineDWOSection =
467       Ctx->getELFSection(".debug_line.dwo", DebugSecType, ELF::SHF_EXCLUDE);
468   DwarfLocDWOSection =
469       Ctx->getELFSection(".debug_loc.dwo", DebugSecType, ELF::SHF_EXCLUDE);
470   DwarfStrOffDWOSection = Ctx->getELFSection(".debug_str_offsets.dwo",
471                                              DebugSecType, ELF::SHF_EXCLUDE);
472   DwarfRnglistsDWOSection =
473       Ctx->getELFSection(".debug_rnglists.dwo", DebugSecType, ELF::SHF_EXCLUDE);
474   DwarfMacinfoDWOSection =
475       Ctx->getELFSection(".debug_macinfo.dwo", DebugSecType, ELF::SHF_EXCLUDE);
476 
477   DwarfLoclistsDWOSection =
478       Ctx->getELFSection(".debug_loclists.dwo", DebugSecType, ELF::SHF_EXCLUDE);
479 
480   // DWP Sections
481   DwarfCUIndexSection =
482       Ctx->getELFSection(".debug_cu_index", DebugSecType, 0);
483   DwarfTUIndexSection =
484       Ctx->getELFSection(".debug_tu_index", DebugSecType, 0);
485 
486   StackMapSection =
487       Ctx->getELFSection(".llvm_stackmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
488 
489   FaultMapSection =
490       Ctx->getELFSection(".llvm_faultmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
491 
492   EHFrameSection =
493       Ctx->getELFSection(".eh_frame", EHSectionType, EHSectionFlags);
494 
495   StackSizesSection = Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, 0);
496 }
497 
498 void MCObjectFileInfo::initCOFFMCObjectFileInfo(const Triple &T) {
499   EHFrameSection =
500       Ctx->getCOFFSection(".eh_frame", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
501                                            COFF::IMAGE_SCN_MEM_READ,
502                           SectionKind::getData());
503 
504   // Set the `IMAGE_SCN_MEM_16BIT` flag when compiling for thumb mode.  This is
505   // used to indicate to the linker that the text segment contains thumb instructions
506   // and to set the ISA selection bit for calls accordingly.
507   const bool IsThumb = T.getArch() == Triple::thumb;
508 
509   CommDirectiveSupportsAlignment = true;
510 
511   // COFF
512   BSSSection = Ctx->getCOFFSection(
513       ".bss", COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
514                   COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
515       SectionKind::getBSS());
516   TextSection = Ctx->getCOFFSection(
517       ".text",
518       (IsThumb ? COFF::IMAGE_SCN_MEM_16BIT : (COFF::SectionCharacteristics)0) |
519           COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE |
520           COFF::IMAGE_SCN_MEM_READ,
521       SectionKind::getText());
522   DataSection = Ctx->getCOFFSection(
523       ".data", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
524                    COFF::IMAGE_SCN_MEM_WRITE,
525       SectionKind::getData());
526   ReadOnlySection = Ctx->getCOFFSection(
527       ".rdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
528       SectionKind::getReadOnly());
529 
530   if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::aarch64) {
531     // On Windows 64 with SEH, the LSDA is emitted into the .xdata section
532     LSDASection = nullptr;
533   } else {
534     LSDASection = Ctx->getCOFFSection(".gcc_except_table",
535                                       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
536                                           COFF::IMAGE_SCN_MEM_READ,
537                                       SectionKind::getReadOnly());
538   }
539 
540   // Debug info.
541   COFFDebugSymbolsSection =
542       Ctx->getCOFFSection(".debug$S", (COFF::IMAGE_SCN_MEM_DISCARDABLE |
543                                        COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
544                                        COFF::IMAGE_SCN_MEM_READ),
545                           SectionKind::getMetadata());
546   COFFDebugTypesSection =
547       Ctx->getCOFFSection(".debug$T", (COFF::IMAGE_SCN_MEM_DISCARDABLE |
548                                        COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
549                                        COFF::IMAGE_SCN_MEM_READ),
550                           SectionKind::getMetadata());
551   COFFGlobalTypeHashesSection = Ctx->getCOFFSection(
552       ".debug$H",
553       (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
554        COFF::IMAGE_SCN_MEM_READ),
555       SectionKind::getMetadata());
556 
557   DwarfAbbrevSection = Ctx->getCOFFSection(
558       ".debug_abbrev",
559       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
560           COFF::IMAGE_SCN_MEM_READ,
561       SectionKind::getMetadata(), "section_abbrev");
562   DwarfInfoSection = Ctx->getCOFFSection(
563       ".debug_info",
564       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
565           COFF::IMAGE_SCN_MEM_READ,
566       SectionKind::getMetadata(), "section_info");
567   DwarfLineSection = Ctx->getCOFFSection(
568       ".debug_line",
569       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
570           COFF::IMAGE_SCN_MEM_READ,
571       SectionKind::getMetadata(), "section_line");
572   DwarfLineStrSection = Ctx->getCOFFSection(
573       ".debug_line_str",
574       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
575           COFF::IMAGE_SCN_MEM_READ,
576       SectionKind::getMetadata(), "section_line_str");
577   DwarfFrameSection = Ctx->getCOFFSection(
578       ".debug_frame",
579       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
580           COFF::IMAGE_SCN_MEM_READ,
581       SectionKind::getMetadata());
582   DwarfPubNamesSection = Ctx->getCOFFSection(
583       ".debug_pubnames",
584       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
585           COFF::IMAGE_SCN_MEM_READ,
586       SectionKind::getMetadata());
587   DwarfPubTypesSection = Ctx->getCOFFSection(
588       ".debug_pubtypes",
589       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
590           COFF::IMAGE_SCN_MEM_READ,
591       SectionKind::getMetadata());
592   DwarfGnuPubNamesSection = Ctx->getCOFFSection(
593       ".debug_gnu_pubnames",
594       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
595           COFF::IMAGE_SCN_MEM_READ,
596       SectionKind::getMetadata());
597   DwarfGnuPubTypesSection = Ctx->getCOFFSection(
598       ".debug_gnu_pubtypes",
599       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
600           COFF::IMAGE_SCN_MEM_READ,
601       SectionKind::getMetadata());
602   DwarfStrSection = Ctx->getCOFFSection(
603       ".debug_str",
604       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
605           COFF::IMAGE_SCN_MEM_READ,
606       SectionKind::getMetadata(), "info_string");
607   DwarfStrOffSection = Ctx->getCOFFSection(
608       ".debug_str_offsets",
609       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
610           COFF::IMAGE_SCN_MEM_READ,
611       SectionKind::getMetadata(), "section_str_off");
612   DwarfLocSection = Ctx->getCOFFSection(
613       ".debug_loc",
614       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
615           COFF::IMAGE_SCN_MEM_READ,
616       SectionKind::getMetadata(), "section_debug_loc");
617   DwarfLoclistsSection = Ctx->getCOFFSection(
618       ".debug_loclists",
619       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
620           COFF::IMAGE_SCN_MEM_READ,
621       SectionKind::getMetadata(), "section_debug_loclists");
622   DwarfARangesSection = Ctx->getCOFFSection(
623       ".debug_aranges",
624       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
625           COFF::IMAGE_SCN_MEM_READ,
626       SectionKind::getMetadata());
627   DwarfRangesSection = Ctx->getCOFFSection(
628       ".debug_ranges",
629       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
630           COFF::IMAGE_SCN_MEM_READ,
631       SectionKind::getMetadata(), "debug_range");
632   DwarfRnglistsSection = Ctx->getCOFFSection(
633       ".debug_rnglists",
634       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
635           COFF::IMAGE_SCN_MEM_READ,
636       SectionKind::getMetadata(), "debug_rnglists");
637   DwarfMacinfoSection = Ctx->getCOFFSection(
638       ".debug_macinfo",
639       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
640           COFF::IMAGE_SCN_MEM_READ,
641       SectionKind::getMetadata(), "debug_macinfo");
642   DwarfMacroSection = Ctx->getCOFFSection(
643       ".debug_macro",
644       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
645           COFF::IMAGE_SCN_MEM_READ,
646       SectionKind::getMetadata(), "debug_macro");
647   DwarfMacinfoDWOSection = Ctx->getCOFFSection(
648       ".debug_macinfo.dwo",
649       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
650           COFF::IMAGE_SCN_MEM_READ,
651       SectionKind::getMetadata(), "debug_macinfo.dwo");
652   DwarfInfoDWOSection = Ctx->getCOFFSection(
653       ".debug_info.dwo",
654       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
655           COFF::IMAGE_SCN_MEM_READ,
656       SectionKind::getMetadata(), "section_info_dwo");
657   DwarfTypesDWOSection = Ctx->getCOFFSection(
658       ".debug_types.dwo",
659       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
660           COFF::IMAGE_SCN_MEM_READ,
661       SectionKind::getMetadata(), "section_types_dwo");
662   DwarfAbbrevDWOSection = Ctx->getCOFFSection(
663       ".debug_abbrev.dwo",
664       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
665           COFF::IMAGE_SCN_MEM_READ,
666       SectionKind::getMetadata(), "section_abbrev_dwo");
667   DwarfStrDWOSection = Ctx->getCOFFSection(
668       ".debug_str.dwo",
669       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
670           COFF::IMAGE_SCN_MEM_READ,
671       SectionKind::getMetadata(), "skel_string");
672   DwarfLineDWOSection = Ctx->getCOFFSection(
673       ".debug_line.dwo",
674       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
675           COFF::IMAGE_SCN_MEM_READ,
676       SectionKind::getMetadata());
677   DwarfLocDWOSection = Ctx->getCOFFSection(
678       ".debug_loc.dwo",
679       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
680           COFF::IMAGE_SCN_MEM_READ,
681       SectionKind::getMetadata(), "skel_loc");
682   DwarfStrOffDWOSection = Ctx->getCOFFSection(
683       ".debug_str_offsets.dwo",
684       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
685           COFF::IMAGE_SCN_MEM_READ,
686       SectionKind::getMetadata(), "section_str_off_dwo");
687   DwarfAddrSection = Ctx->getCOFFSection(
688       ".debug_addr",
689       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
690           COFF::IMAGE_SCN_MEM_READ,
691       SectionKind::getMetadata(), "addr_sec");
692   DwarfCUIndexSection = Ctx->getCOFFSection(
693       ".debug_cu_index",
694       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
695           COFF::IMAGE_SCN_MEM_READ,
696       SectionKind::getMetadata());
697   DwarfTUIndexSection = Ctx->getCOFFSection(
698       ".debug_tu_index",
699       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
700           COFF::IMAGE_SCN_MEM_READ,
701       SectionKind::getMetadata());
702   DwarfDebugNamesSection = Ctx->getCOFFSection(
703       ".debug_names",
704       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
705           COFF::IMAGE_SCN_MEM_READ,
706       SectionKind::getMetadata(), "debug_names_begin");
707   DwarfAccelNamesSection = Ctx->getCOFFSection(
708       ".apple_names",
709       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
710           COFF::IMAGE_SCN_MEM_READ,
711       SectionKind::getMetadata(), "names_begin");
712   DwarfAccelNamespaceSection = Ctx->getCOFFSection(
713       ".apple_namespaces",
714       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
715           COFF::IMAGE_SCN_MEM_READ,
716       SectionKind::getMetadata(), "namespac_begin");
717   DwarfAccelTypesSection = Ctx->getCOFFSection(
718       ".apple_types",
719       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
720           COFF::IMAGE_SCN_MEM_READ,
721       SectionKind::getMetadata(), "types_begin");
722   DwarfAccelObjCSection = Ctx->getCOFFSection(
723       ".apple_objc",
724       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
725           COFF::IMAGE_SCN_MEM_READ,
726       SectionKind::getMetadata(), "objc_begin");
727 
728   DrectveSection = Ctx->getCOFFSection(
729       ".drectve", COFF::IMAGE_SCN_LNK_INFO | COFF::IMAGE_SCN_LNK_REMOVE,
730       SectionKind::getMetadata());
731 
732   PDataSection = Ctx->getCOFFSection(
733       ".pdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
734       SectionKind::getData());
735 
736   XDataSection = Ctx->getCOFFSection(
737       ".xdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
738       SectionKind::getData());
739 
740   SXDataSection = Ctx->getCOFFSection(".sxdata", COFF::IMAGE_SCN_LNK_INFO,
741                                       SectionKind::getMetadata());
742 
743   GFIDsSection = Ctx->getCOFFSection(".gfids$y",
744                                      COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
745                                          COFF::IMAGE_SCN_MEM_READ,
746                                      SectionKind::getMetadata());
747 
748   GLJMPSection = Ctx->getCOFFSection(".gljmp$y",
749                                      COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
750                                          COFF::IMAGE_SCN_MEM_READ,
751                                      SectionKind::getMetadata());
752 
753   TLSDataSection = Ctx->getCOFFSection(
754       ".tls$", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
755                    COFF::IMAGE_SCN_MEM_WRITE,
756       SectionKind::getData());
757 
758   StackMapSection = Ctx->getCOFFSection(".llvm_stackmaps",
759                                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
760                                             COFF::IMAGE_SCN_MEM_READ,
761                                         SectionKind::getReadOnly());
762 }
763 
764 void MCObjectFileInfo::initWasmMCObjectFileInfo(const Triple &T) {
765   TextSection = Ctx->getWasmSection(".text", SectionKind::getText());
766   DataSection = Ctx->getWasmSection(".data", SectionKind::getData());
767 
768   DwarfLineSection =
769       Ctx->getWasmSection(".debug_line", SectionKind::getMetadata());
770   DwarfLineStrSection =
771       Ctx->getWasmSection(".debug_line_str", SectionKind::getMetadata());
772   DwarfStrSection =
773       Ctx->getWasmSection(".debug_str", SectionKind::getMetadata());
774   DwarfLocSection =
775       Ctx->getWasmSection(".debug_loc", SectionKind::getMetadata());
776   DwarfAbbrevSection =
777       Ctx->getWasmSection(".debug_abbrev", SectionKind::getMetadata());
778   DwarfARangesSection = Ctx->getWasmSection(".debug_aranges", SectionKind::getMetadata());
779   DwarfRangesSection =
780       Ctx->getWasmSection(".debug_ranges", SectionKind::getMetadata());
781   DwarfMacinfoSection =
782       Ctx->getWasmSection(".debug_macinfo", SectionKind::getMetadata());
783   DwarfMacroSection =
784       Ctx->getWasmSection(".debug_macro", SectionKind::getMetadata());
785   DwarfCUIndexSection = Ctx->getWasmSection(".debug_cu_index", SectionKind::getMetadata());
786   DwarfTUIndexSection = Ctx->getWasmSection(".debug_tu_index", SectionKind::getMetadata());
787   DwarfInfoSection =
788       Ctx->getWasmSection(".debug_info", SectionKind::getMetadata());
789   DwarfFrameSection = Ctx->getWasmSection(".debug_frame", SectionKind::getMetadata());
790   DwarfPubNamesSection = Ctx->getWasmSection(".debug_pubnames", SectionKind::getMetadata());
791   DwarfPubTypesSection = Ctx->getWasmSection(".debug_pubtypes", SectionKind::getMetadata());
792 
793   DwarfDebugNamesSection =
794       Ctx->getWasmSection(".debug_names", SectionKind::getMetadata());
795   DwarfStrOffSection =
796       Ctx->getWasmSection(".debug_str_offsets", SectionKind::getMetadata());
797   DwarfAddrSection =
798       Ctx->getWasmSection(".debug_addr", SectionKind::getMetadata());
799   DwarfRnglistsSection =
800       Ctx->getWasmSection(".debug_rnglists", SectionKind::getMetadata());
801   DwarfLoclistsSection =
802       Ctx->getWasmSection(".debug_loclists", SectionKind::getMetadata());
803 
804   // Wasm use data section for LSDA.
805   // TODO Consider putting each function's exception table in a separate
806   // section, as in -function-sections, to facilitate lld's --gc-section.
807   LSDASection = Ctx->getWasmSection(".rodata.gcc_except_table",
808                                     SectionKind::getReadOnlyWithRel());
809 
810   // TODO: Define more sections.
811 }
812 
813 void MCObjectFileInfo::initXCOFFMCObjectFileInfo(const Triple &T) {
814   // The default csect for program code. Functions without a specified section
815   // get placed into this csect. The choice of csect name is not a property of
816   // the ABI or object file format. For example, the XL compiler uses an unnamed
817   // csect for program code.
818   TextSection = Ctx->getXCOFFSection(
819       ".text", XCOFF::StorageMappingClass::XMC_PR, XCOFF::XTY_SD,
820       XCOFF::C_HIDEXT, SectionKind::getText());
821 
822   DataSection = Ctx->getXCOFFSection(
823       ".data", XCOFF::StorageMappingClass::XMC_RW, XCOFF::XTY_SD,
824       XCOFF::C_HIDEXT, SectionKind::getData());
825 
826   ReadOnlySection = Ctx->getXCOFFSection(
827       ".rodata", XCOFF::StorageMappingClass::XMC_RO, XCOFF::XTY_SD,
828       XCOFF::C_HIDEXT, SectionKind::getReadOnly());
829 
830   TOCBaseSection = Ctx->getXCOFFSection(
831       "TOC", XCOFF::StorageMappingClass::XMC_TC0, XCOFF::XTY_SD,
832       XCOFF::C_HIDEXT, SectionKind::getData());
833 
834   // The TOC-base always has 0 size, but 4 byte alignment.
835   TOCBaseSection->setAlignment(Align(4));
836 
837   // DWARF sections for XCOFF are not csects. They are special STYP_DWARF
838   // sections, and the individual DWARF sections are distinguished by their
839   // section subtype.
840   // TODO: Populate the DWARF sections appropriately.
841   DwarfAbbrevSection = nullptr;   // SSUBTYP_DWABREV
842   DwarfInfoSection = nullptr;     // SSUBTYP_DWINFO
843   DwarfLineSection = nullptr;     // SSUBTYP_DWLINE
844   DwarfFrameSection = nullptr;    // SSUBTYP_DWFRAME
845   DwarfPubNamesSection = nullptr; // SSUBTYP_DWPBNMS
846   DwarfPubTypesSection = nullptr; // SSUBTYP_DWPBTYP
847   DwarfStrSection = nullptr;      // SSUBTYP_DWSTR
848   DwarfLocSection = nullptr;      // SSUBTYP_DWLOC
849   DwarfARangesSection = nullptr;  // SSUBTYP_DWARNGE
850   DwarfRangesSection = nullptr;   // SSUBTYP_DWRNGES
851   DwarfMacinfoSection = nullptr;  // SSUBTYP_DWMAC
852 }
853 
854 void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple, bool PIC,
855                                             MCContext &ctx,
856                                             bool LargeCodeModel) {
857   PositionIndependent = PIC;
858   Ctx = &ctx;
859 
860   // Common.
861   CommDirectiveSupportsAlignment = true;
862   SupportsWeakOmittedEHFrame = true;
863   SupportsCompactUnwindWithoutEHFrame = false;
864   OmitDwarfIfHaveCompactUnwind = false;
865 
866   FDECFIEncoding = dwarf::DW_EH_PE_absptr;
867 
868   CompactUnwindDwarfEHFrameOnly = 0;
869 
870   EHFrameSection = nullptr;             // Created on demand.
871   CompactUnwindSection = nullptr;       // Used only by selected targets.
872   DwarfAccelNamesSection = nullptr;     // Used only by selected targets.
873   DwarfAccelObjCSection = nullptr;      // Used only by selected targets.
874   DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
875   DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
876 
877   TT = TheTriple;
878 
879   switch (TT.getObjectFormat()) {
880   case Triple::MachO:
881     Env = IsMachO;
882     initMachOMCObjectFileInfo(TT);
883     break;
884   case Triple::COFF:
885     if (!TT.isOSWindows())
886       report_fatal_error(
887           "Cannot initialize MC for non-Windows COFF object files.");
888 
889     Env = IsCOFF;
890     initCOFFMCObjectFileInfo(TT);
891     break;
892   case Triple::ELF:
893     Env = IsELF;
894     initELFMCObjectFileInfo(TT, LargeCodeModel);
895     break;
896   case Triple::Wasm:
897     Env = IsWasm;
898     initWasmMCObjectFileInfo(TT);
899     break;
900   case Triple::XCOFF:
901     Env = IsXCOFF;
902     initXCOFFMCObjectFileInfo(TT);
903     break;
904   case Triple::UnknownObjectFormat:
905     report_fatal_error("Cannot initialize MC for unknown object file format.");
906     break;
907   }
908 }
909 
910 MCSection *MCObjectFileInfo::getDwarfComdatSection(const char *Name,
911                                                    uint64_t Hash) const {
912   switch (TT.getObjectFormat()) {
913   case Triple::ELF:
914     return Ctx->getELFSection(Name, ELF::SHT_PROGBITS, ELF::SHF_GROUP, 0,
915                               utostr(Hash));
916   case Triple::MachO:
917   case Triple::COFF:
918   case Triple::Wasm:
919   case Triple::XCOFF:
920   case Triple::UnknownObjectFormat:
921     report_fatal_error("Cannot get DWARF comdat section for this object file "
922                        "format: not implemented.");
923     break;
924   }
925   llvm_unreachable("Unknown ObjectFormatType");
926 }
927 
928 MCSection *
929 MCObjectFileInfo::getStackSizesSection(const MCSection &TextSec) const {
930   if (Env != IsELF)
931     return StackSizesSection;
932 
933   const MCSectionELF &ElfSec = static_cast<const MCSectionELF &>(TextSec);
934   unsigned Flags = ELF::SHF_LINK_ORDER;
935   StringRef GroupName;
936   if (const MCSymbol *Group = ElfSec.getGroup()) {
937     GroupName = Group->getName();
938     Flags |= ELF::SHF_GROUP;
939   }
940 
941   return Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, Flags, 0,
942                             GroupName, MCSection::NonUniqueID,
943                             cast<MCSymbolELF>(TextSec.getBeginSymbol()));
944 }
945