1 //===-- MObjectFileInfo.cpp - Object File Information ---------------------===//
2 //
3 //                     The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 
10 #include "llvm/MC/MCObjectFileInfo.h"
11 #include "llvm/ADT/StringExtras.h"
12 #include "llvm/ADT/Triple.h"
13 #include "llvm/MC/MCAsmInfo.h"
14 #include "llvm/MC/MCContext.h"
15 #include "llvm/MC/MCSection.h"
16 #include "llvm/MC/MCSectionCOFF.h"
17 #include "llvm/MC/MCSectionELF.h"
18 #include "llvm/MC/MCSectionMachO.h"
19 using namespace llvm;
20 
21 static bool useCompactUnwind(const Triple &T) {
22   // Only on darwin.
23   if (!T.isOSDarwin())
24     return false;
25 
26   // aarch64 always has it.
27   if (T.getArch() == Triple::aarch64)
28     return true;
29 
30   // Use it on newer version of OS X.
31   if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6))
32     return true;
33 
34   // And the iOS simulator.
35   if (T.isiOS() &&
36       (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86))
37     return true;
38 
39   return false;
40 }
41 
42 void MCObjectFileInfo::InitMachOMCObjectFileInfo(Triple T) {
43   // MachO
44   SupportsWeakOmittedEHFrame = false;
45 
46   if (T.isOSDarwin() && T.getArch() == Triple::aarch64)
47     SupportsCompactUnwindWithoutEHFrame = true;
48 
49   PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel
50     | dwarf::DW_EH_PE_sdata4;
51   LSDAEncoding = FDECFIEncoding = dwarf::DW_EH_PE_pcrel;
52   TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
53     dwarf::DW_EH_PE_sdata4;
54 
55   // .comm doesn't support alignment before Leopard.
56   if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
57     CommDirectiveSupportsAlignment = false;
58 
59   TextSection // .text
60     = Ctx->getMachOSection("__TEXT", "__text",
61                            MachO::S_ATTR_PURE_INSTRUCTIONS,
62                            SectionKind::getText());
63   DataSection // .data
64     = Ctx->getMachOSection("__DATA", "__data", 0,
65                            SectionKind::getDataRel());
66 
67   // BSSSection might not be expected initialized on msvc.
68   BSSSection = nullptr;
69 
70   TLSDataSection // .tdata
71     = Ctx->getMachOSection("__DATA", "__thread_data",
72                            MachO::S_THREAD_LOCAL_REGULAR,
73                            SectionKind::getDataRel());
74   TLSBSSSection // .tbss
75     = Ctx->getMachOSection("__DATA", "__thread_bss",
76                            MachO::S_THREAD_LOCAL_ZEROFILL,
77                            SectionKind::getThreadBSS());
78 
79   // TODO: Verify datarel below.
80   TLSTLVSection // .tlv
81     = Ctx->getMachOSection("__DATA", "__thread_vars",
82                            MachO::S_THREAD_LOCAL_VARIABLES,
83                            SectionKind::getDataRel());
84 
85   TLSThreadInitSection
86     = Ctx->getMachOSection("__DATA", "__thread_init",
87                           MachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
88                           SectionKind::getDataRel());
89 
90   CStringSection // .cstring
91     = Ctx->getMachOSection("__TEXT", "__cstring",
92                            MachO::S_CSTRING_LITERALS,
93                            SectionKind::getMergeable1ByteCString());
94   UStringSection
95     = Ctx->getMachOSection("__TEXT","__ustring", 0,
96                            SectionKind::getMergeable2ByteCString());
97   FourByteConstantSection // .literal4
98     = Ctx->getMachOSection("__TEXT", "__literal4",
99                            MachO::S_4BYTE_LITERALS,
100                            SectionKind::getMergeableConst4());
101   EightByteConstantSection // .literal8
102     = Ctx->getMachOSection("__TEXT", "__literal8",
103                            MachO::S_8BYTE_LITERALS,
104                            SectionKind::getMergeableConst8());
105 
106   SixteenByteConstantSection // .literal16
107       = Ctx->getMachOSection("__TEXT", "__literal16",
108                              MachO::S_16BYTE_LITERALS,
109                              SectionKind::getMergeableConst16());
110 
111   ReadOnlySection  // .const
112     = Ctx->getMachOSection("__TEXT", "__const", 0,
113                            SectionKind::getReadOnly());
114 
115   TextCoalSection
116     = Ctx->getMachOSection("__TEXT", "__textcoal_nt",
117                            MachO::S_COALESCED |
118                            MachO::S_ATTR_PURE_INSTRUCTIONS,
119                            SectionKind::getText());
120   ConstTextCoalSection
121     = Ctx->getMachOSection("__TEXT", "__const_coal",
122                            MachO::S_COALESCED,
123                            SectionKind::getReadOnly());
124   ConstDataSection  // .const_data
125     = Ctx->getMachOSection("__DATA", "__const", 0,
126                            SectionKind::getReadOnlyWithRel());
127   DataCoalSection
128     = Ctx->getMachOSection("__DATA","__datacoal_nt",
129                            MachO::S_COALESCED,
130                            SectionKind::getDataRel());
131   DataCommonSection
132     = Ctx->getMachOSection("__DATA","__common",
133                            MachO::S_ZEROFILL,
134                            SectionKind::getBSS());
135   DataBSSSection
136     = Ctx->getMachOSection("__DATA","__bss", MachO::S_ZEROFILL,
137                            SectionKind::getBSS());
138 
139 
140   LazySymbolPointerSection
141     = Ctx->getMachOSection("__DATA", "__la_symbol_ptr",
142                            MachO::S_LAZY_SYMBOL_POINTERS,
143                            SectionKind::getMetadata());
144   NonLazySymbolPointerSection
145     = Ctx->getMachOSection("__DATA", "__nl_symbol_ptr",
146                            MachO::S_NON_LAZY_SYMBOL_POINTERS,
147                            SectionKind::getMetadata());
148 
149   if (RelocM == Reloc::Static) {
150     StaticCtorSection
151       = Ctx->getMachOSection("__TEXT", "__constructor", 0,
152                              SectionKind::getDataRel());
153     StaticDtorSection
154       = Ctx->getMachOSection("__TEXT", "__destructor", 0,
155                              SectionKind::getDataRel());
156   } else {
157     StaticCtorSection
158       = Ctx->getMachOSection("__DATA", "__mod_init_func",
159                              MachO::S_MOD_INIT_FUNC_POINTERS,
160                              SectionKind::getDataRel());
161     StaticDtorSection
162       = Ctx->getMachOSection("__DATA", "__mod_term_func",
163                              MachO::S_MOD_TERM_FUNC_POINTERS,
164                              SectionKind::getDataRel());
165   }
166 
167   // Exception Handling.
168   LSDASection = Ctx->getMachOSection("__TEXT", "__gcc_except_tab", 0,
169                                      SectionKind::getReadOnlyWithRel());
170 
171   COFFDebugSymbolsSection = nullptr;
172 
173   if (useCompactUnwind(T)) {
174     CompactUnwindSection =
175         Ctx->getMachOSection("__LD", "__compact_unwind", MachO::S_ATTR_DEBUG,
176                              SectionKind::getReadOnly());
177 
178     if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86)
179       CompactUnwindDwarfEHFrameOnly = 0x04000000;
180     else if (T.getArch() == Triple::aarch64)
181       CompactUnwindDwarfEHFrameOnly = 0x03000000;
182   }
183 
184   // Debug Information.
185   DwarfAccelNamesSection =
186     Ctx->getMachOSection("__DWARF", "__apple_names",
187                          MachO::S_ATTR_DEBUG,
188                          SectionKind::getMetadata());
189   DwarfAccelObjCSection =
190     Ctx->getMachOSection("__DWARF", "__apple_objc",
191                          MachO::S_ATTR_DEBUG,
192                          SectionKind::getMetadata());
193   // 16 character section limit...
194   DwarfAccelNamespaceSection =
195     Ctx->getMachOSection("__DWARF", "__apple_namespac",
196                          MachO::S_ATTR_DEBUG,
197                          SectionKind::getMetadata());
198   DwarfAccelTypesSection =
199     Ctx->getMachOSection("__DWARF", "__apple_types",
200                          MachO::S_ATTR_DEBUG,
201                          SectionKind::getMetadata());
202 
203   DwarfAbbrevSection =
204     Ctx->getMachOSection("__DWARF", "__debug_abbrev",
205                          MachO::S_ATTR_DEBUG,
206                          SectionKind::getMetadata());
207   DwarfInfoSection =
208     Ctx->getMachOSection("__DWARF", "__debug_info",
209                          MachO::S_ATTR_DEBUG,
210                          SectionKind::getMetadata());
211   DwarfLineSection =
212     Ctx->getMachOSection("__DWARF", "__debug_line",
213                          MachO::S_ATTR_DEBUG,
214                          SectionKind::getMetadata());
215   DwarfFrameSection =
216     Ctx->getMachOSection("__DWARF", "__debug_frame",
217                          MachO::S_ATTR_DEBUG,
218                          SectionKind::getMetadata());
219   DwarfPubNamesSection =
220     Ctx->getMachOSection("__DWARF", "__debug_pubnames",
221                          MachO::S_ATTR_DEBUG,
222                          SectionKind::getMetadata());
223   DwarfPubTypesSection =
224     Ctx->getMachOSection("__DWARF", "__debug_pubtypes",
225                          MachO::S_ATTR_DEBUG,
226                          SectionKind::getMetadata());
227   DwarfGnuPubNamesSection =
228     Ctx->getMachOSection("__DWARF", "__debug_gnu_pubn",
229                          MachO::S_ATTR_DEBUG,
230                          SectionKind::getMetadata());
231   DwarfGnuPubTypesSection =
232     Ctx->getMachOSection("__DWARF", "__debug_gnu_pubt",
233                          MachO::S_ATTR_DEBUG,
234                          SectionKind::getMetadata());
235   DwarfStrSection =
236     Ctx->getMachOSection("__DWARF", "__debug_str",
237                          MachO::S_ATTR_DEBUG,
238                          SectionKind::getMetadata());
239   DwarfLocSection =
240     Ctx->getMachOSection("__DWARF", "__debug_loc",
241                          MachO::S_ATTR_DEBUG,
242                          SectionKind::getMetadata());
243   DwarfARangesSection =
244     Ctx->getMachOSection("__DWARF", "__debug_aranges",
245                          MachO::S_ATTR_DEBUG,
246                          SectionKind::getMetadata());
247   DwarfRangesSection =
248     Ctx->getMachOSection("__DWARF", "__debug_ranges",
249                          MachO::S_ATTR_DEBUG,
250                          SectionKind::getMetadata());
251   DwarfMacroInfoSection =
252     Ctx->getMachOSection("__DWARF", "__debug_macinfo",
253                          MachO::S_ATTR_DEBUG,
254                          SectionKind::getMetadata());
255   DwarfDebugInlineSection =
256     Ctx->getMachOSection("__DWARF", "__debug_inlined",
257                          MachO::S_ATTR_DEBUG,
258                          SectionKind::getMetadata());
259   StackMapSection =
260     Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps", 0,
261                          SectionKind::getMetadata());
262 
263   TLSExtraDataSection = TLSTLVSection;
264 }
265 
266 void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
267   switch (T.getArch()) {
268   case Triple::mips:
269   case Triple::mipsel:
270     FDECFIEncoding = dwarf::DW_EH_PE_sdata4;
271     break;
272   case Triple::mips64:
273   case Triple::mips64el:
274     FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
275     break;
276   default:
277     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
278     break;
279   }
280 
281   switch (T.getArch()) {
282   case Triple::arm:
283   case Triple::armeb:
284   case Triple::thumb:
285   case Triple::thumbeb:
286     if (Ctx->getAsmInfo()->getExceptionHandlingType() == ExceptionHandling::ARM)
287       break;
288     // Fallthrough if not using EHABI
289   case Triple::ppc:
290   case Triple::x86:
291     PersonalityEncoding = (RelocM == Reloc::PIC_)
292      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
293      : dwarf::DW_EH_PE_absptr;
294     LSDAEncoding = (RelocM == Reloc::PIC_)
295       ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
296       : dwarf::DW_EH_PE_absptr;
297     TTypeEncoding = (RelocM == Reloc::PIC_)
298      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
299      : dwarf::DW_EH_PE_absptr;
300     break;
301   case Triple::x86_64:
302     if (RelocM == Reloc::PIC_) {
303       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
304         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
305          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
306       LSDAEncoding = dwarf::DW_EH_PE_pcrel |
307         (CMModel == CodeModel::Small
308          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
309       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
310         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
311          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
312     } else {
313       PersonalityEncoding =
314         (CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
315         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
316       LSDAEncoding = (CMModel == CodeModel::Small)
317         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
318       TTypeEncoding = (CMModel == CodeModel::Small)
319         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
320     }
321     break;
322   case Triple::aarch64:
323   case Triple::aarch64_be:
324     // The small model guarantees static code/data size < 4GB, but not where it
325     // will be in memory. Most of these could end up >2GB away so even a signed
326     // pc-relative 32-bit address is insufficient, theoretically.
327     if (RelocM == Reloc::PIC_) {
328       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
329         dwarf::DW_EH_PE_sdata8;
330       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
331       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
332         dwarf::DW_EH_PE_sdata8;
333     } else {
334       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
335       LSDAEncoding = dwarf::DW_EH_PE_absptr;
336       TTypeEncoding = dwarf::DW_EH_PE_absptr;
337     }
338     break;
339   case Triple::mips:
340   case Triple::mipsel:
341     // MIPS uses indirect pointer to refer personality functions, so that the
342     // eh_frame section can be read-only.  DW.ref.personality will be generated
343     // for relocation.
344     PersonalityEncoding = dwarf::DW_EH_PE_indirect;
345     break;
346   case Triple::ppc64:
347   case Triple::ppc64le:
348     PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
349       dwarf::DW_EH_PE_udata8;
350     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8;
351     TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
352       dwarf::DW_EH_PE_udata8;
353     break;
354   case Triple::sparc:
355     if (RelocM == Reloc::PIC_) {
356       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
357       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
358         dwarf::DW_EH_PE_sdata4;
359       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
360         dwarf::DW_EH_PE_sdata4;
361     } else {
362       LSDAEncoding = dwarf::DW_EH_PE_absptr;
363       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
364       TTypeEncoding = dwarf::DW_EH_PE_absptr;
365     }
366     break;
367   case Triple::sparcv9:
368     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
369     if (RelocM == Reloc::PIC_) {
370       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
371         dwarf::DW_EH_PE_sdata4;
372       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
373         dwarf::DW_EH_PE_sdata4;
374     } else {
375       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
376       TTypeEncoding = dwarf::DW_EH_PE_absptr;
377     }
378     break;
379   case Triple::systemz:
380     // All currently-defined code models guarantee that 4-byte PC-relative
381     // values will be in range.
382     if (RelocM == Reloc::PIC_) {
383       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
384         dwarf::DW_EH_PE_sdata4;
385       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
386       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
387         dwarf::DW_EH_PE_sdata4;
388     } else {
389       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
390       LSDAEncoding = dwarf::DW_EH_PE_absptr;
391       TTypeEncoding = dwarf::DW_EH_PE_absptr;
392     }
393     break;
394   default:
395     break;
396   }
397 
398   // Solaris requires different flags for .eh_frame to seemingly every other
399   // platform.
400   EHSectionType = ELF::SHT_PROGBITS;
401   EHSectionFlags = ELF::SHF_ALLOC;
402   if (T.getOS() == Triple::Solaris) {
403     if (T.getArch() == Triple::x86_64)
404       EHSectionType = ELF::SHT_X86_64_UNWIND;
405     else
406       EHSectionFlags |= ELF::SHF_WRITE;
407   }
408 
409 
410   // ELF
411   BSSSection =
412     Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
413                        ELF::SHF_WRITE | ELF::SHF_ALLOC,
414                        SectionKind::getBSS());
415 
416   TextSection =
417     Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
418                        ELF::SHF_EXECINSTR |
419                        ELF::SHF_ALLOC,
420                        SectionKind::getText());
421 
422   DataSection =
423     Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
424                        ELF::SHF_WRITE |ELF::SHF_ALLOC,
425                        SectionKind::getDataRel());
426 
427   ReadOnlySection =
428     Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS,
429                        ELF::SHF_ALLOC,
430                        SectionKind::getReadOnly());
431 
432   TLSDataSection =
433     Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
434                        ELF::SHF_ALLOC | ELF::SHF_TLS |
435                        ELF::SHF_WRITE,
436                        SectionKind::getThreadData());
437 
438   TLSBSSSection =
439     Ctx->getELFSection(".tbss", ELF::SHT_NOBITS,
440                        ELF::SHF_ALLOC | ELF::SHF_TLS |
441                        ELF::SHF_WRITE,
442                        SectionKind::getThreadBSS());
443 
444   DataRelSection =
445     Ctx->getELFSection(".data.rel", ELF::SHT_PROGBITS,
446                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
447                        SectionKind::getDataRel());
448 
449   DataRelLocalSection =
450     Ctx->getELFSection(".data.rel.local", ELF::SHT_PROGBITS,
451                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
452                        SectionKind::getDataRelLocal());
453 
454   DataRelROSection =
455     Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
456                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
457                        SectionKind::getReadOnlyWithRel());
458 
459   DataRelROLocalSection =
460     Ctx->getELFSection(".data.rel.ro.local", ELF::SHT_PROGBITS,
461                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
462                        SectionKind::getReadOnlyWithRelLocal());
463 
464   MergeableConst4Section =
465     Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
466                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
467                        SectionKind::getMergeableConst4());
468 
469   MergeableConst8Section =
470     Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
471                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
472                        SectionKind::getMergeableConst8());
473 
474   MergeableConst16Section =
475     Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
476                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
477                        SectionKind::getMergeableConst16());
478 
479   StaticCtorSection =
480     Ctx->getELFSection(".ctors", ELF::SHT_PROGBITS,
481                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
482                        SectionKind::getDataRel());
483 
484   StaticDtorSection =
485     Ctx->getELFSection(".dtors", ELF::SHT_PROGBITS,
486                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
487                        SectionKind::getDataRel());
488 
489   // Exception Handling Sections.
490 
491   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
492   // it contains relocatable pointers.  In PIC mode, this is probably a big
493   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
494   // adjusted or this should be a data section.
495   LSDASection =
496     Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
497                        ELF::SHF_ALLOC,
498                        SectionKind::getReadOnly());
499 
500   COFFDebugSymbolsSection = nullptr;
501 
502   // Debug Info Sections.
503   DwarfAbbrevSection =
504     Ctx->getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0,
505                        SectionKind::getMetadata());
506   DwarfInfoSection =
507     Ctx->getELFSection(".debug_info", ELF::SHT_PROGBITS, 0,
508                        SectionKind::getMetadata());
509   DwarfLineSection =
510     Ctx->getELFSection(".debug_line", ELF::SHT_PROGBITS, 0,
511                        SectionKind::getMetadata());
512   DwarfFrameSection =
513     Ctx->getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0,
514                        SectionKind::getMetadata());
515   DwarfPubNamesSection =
516     Ctx->getELFSection(".debug_pubnames", ELF::SHT_PROGBITS, 0,
517                        SectionKind::getMetadata());
518   DwarfPubTypesSection =
519     Ctx->getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0,
520                        SectionKind::getMetadata());
521   DwarfGnuPubNamesSection =
522     Ctx->getELFSection(".debug_gnu_pubnames", ELF::SHT_PROGBITS, 0,
523                        SectionKind::getMetadata());
524   DwarfGnuPubTypesSection =
525     Ctx->getELFSection(".debug_gnu_pubtypes", ELF::SHT_PROGBITS, 0,
526                        SectionKind::getMetadata());
527   DwarfStrSection =
528     Ctx->getELFSection(".debug_str", ELF::SHT_PROGBITS,
529                        ELF::SHF_MERGE | ELF::SHF_STRINGS,
530                        SectionKind::getMergeable1ByteCString());
531   DwarfLocSection =
532     Ctx->getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0,
533                        SectionKind::getMetadata());
534   DwarfARangesSection =
535     Ctx->getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0,
536                        SectionKind::getMetadata());
537   DwarfRangesSection =
538     Ctx->getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0,
539                        SectionKind::getMetadata());
540   DwarfMacroInfoSection =
541     Ctx->getELFSection(".debug_macinfo", ELF::SHT_PROGBITS, 0,
542                        SectionKind::getMetadata());
543 
544   // DWARF5 Experimental Debug Info
545 
546   // Accelerator Tables
547   DwarfAccelNamesSection =
548     Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0,
549                        SectionKind::getMetadata());
550   DwarfAccelObjCSection =
551     Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0,
552                        SectionKind::getMetadata());
553   DwarfAccelNamespaceSection =
554     Ctx->getELFSection(".apple_namespaces", ELF::SHT_PROGBITS, 0,
555                        SectionKind::getMetadata());
556   DwarfAccelTypesSection =
557     Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0,
558                        SectionKind::getMetadata());
559 
560   // Fission Sections
561   DwarfInfoDWOSection =
562     Ctx->getELFSection(".debug_info.dwo", ELF::SHT_PROGBITS, 0,
563                        SectionKind::getMetadata());
564   DwarfTypesDWOSection =
565     Ctx->getELFSection(".debug_types.dwo", ELF::SHT_PROGBITS, 0,
566                        SectionKind::getMetadata());
567   DwarfAbbrevDWOSection =
568     Ctx->getELFSection(".debug_abbrev.dwo", ELF::SHT_PROGBITS, 0,
569                        SectionKind::getMetadata());
570   DwarfStrDWOSection =
571     Ctx->getELFSection(".debug_str.dwo", ELF::SHT_PROGBITS,
572                        ELF::SHF_MERGE | ELF::SHF_STRINGS,
573                        SectionKind::getMergeable1ByteCString());
574   DwarfLineDWOSection =
575     Ctx->getELFSection(".debug_line.dwo", ELF::SHT_PROGBITS, 0,
576                        SectionKind::getMetadata());
577   DwarfLocDWOSection =
578     Ctx->getELFSection(".debug_loc.dwo", ELF::SHT_PROGBITS, 0,
579                        SectionKind::getMetadata());
580   DwarfStrOffDWOSection =
581     Ctx->getELFSection(".debug_str_offsets.dwo", ELF::SHT_PROGBITS, 0,
582                        SectionKind::getMetadata());
583   DwarfAddrSection =
584     Ctx->getELFSection(".debug_addr", ELF::SHT_PROGBITS, 0,
585                        SectionKind::getMetadata());
586 
587   StackMapSection =
588     Ctx->getELFSection(".llvm_stackmaps", ELF::SHT_PROGBITS,
589                        ELF::SHF_ALLOC,
590                        SectionKind::getMetadata());
591 
592 }
593 
594 
595 void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
596   bool IsWoA = T.getArch() == Triple::arm || T.getArch() == Triple::thumb;
597 
598   // The object file format cannot represent common symbols with explicit
599   // alignments.
600   CommDirectiveSupportsAlignment = false;
601 
602   // COFF
603   BSSSection =
604     Ctx->getCOFFSection(".bss",
605                         COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
606                         COFF::IMAGE_SCN_MEM_READ |
607                         COFF::IMAGE_SCN_MEM_WRITE,
608                         SectionKind::getBSS());
609   TextSection =
610     Ctx->getCOFFSection(".text",
611                         (IsWoA ? COFF::IMAGE_SCN_MEM_16BIT
612                                : (COFF::SectionCharacteristics)0) |
613                         COFF::IMAGE_SCN_CNT_CODE |
614                         COFF::IMAGE_SCN_MEM_EXECUTE |
615                         COFF::IMAGE_SCN_MEM_READ,
616                         SectionKind::getText());
617   DataSection =
618     Ctx->getCOFFSection(".data",
619                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
620                         COFF::IMAGE_SCN_MEM_READ |
621                         COFF::IMAGE_SCN_MEM_WRITE,
622                         SectionKind::getDataRel());
623   ReadOnlySection =
624     Ctx->getCOFFSection(".rdata",
625                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
626                         COFF::IMAGE_SCN_MEM_READ,
627                         SectionKind::getReadOnly());
628 
629   if (T.isKnownWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) {
630     StaticCtorSection =
631       Ctx->getCOFFSection(".CRT$XCU",
632                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
633                           COFF::IMAGE_SCN_MEM_READ,
634                           SectionKind::getReadOnly());
635     StaticDtorSection =
636       Ctx->getCOFFSection(".CRT$XTX",
637                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
638                           COFF::IMAGE_SCN_MEM_READ,
639                           SectionKind::getReadOnly());
640   } else {
641     StaticCtorSection =
642       Ctx->getCOFFSection(".ctors",
643                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
644                           COFF::IMAGE_SCN_MEM_READ |
645                           COFF::IMAGE_SCN_MEM_WRITE,
646                           SectionKind::getDataRel());
647     StaticDtorSection =
648       Ctx->getCOFFSection(".dtors",
649                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
650                           COFF::IMAGE_SCN_MEM_READ |
651                           COFF::IMAGE_SCN_MEM_WRITE,
652                           SectionKind::getDataRel());
653   }
654 
655   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
656   // though it contains relocatable pointers.  In PIC mode, this is probably a
657   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
658   // adjusted or this should be a data section.
659   assert(T.isOSWindows() && "Windows is the only supported COFF target");
660   if (T.getArch() == Triple::x86_64) {
661     // On Windows 64 with SEH, the LSDA is emitted into the .xdata section
662     LSDASection = 0;
663   } else {
664     LSDASection = Ctx->getCOFFSection(".gcc_except_table",
665                                       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
666                                           COFF::IMAGE_SCN_MEM_READ,
667                                       SectionKind::getReadOnly());
668   }
669 
670   // Debug info.
671   COFFDebugSymbolsSection =
672     Ctx->getCOFFSection(".debug$S",
673                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
674                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
675                         COFF::IMAGE_SCN_MEM_READ,
676                         SectionKind::getMetadata());
677 
678   DwarfAbbrevSection =
679     Ctx->getCOFFSection(".debug_abbrev",
680                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
681                         COFF::IMAGE_SCN_MEM_READ,
682                         SectionKind::getMetadata());
683   DwarfInfoSection =
684     Ctx->getCOFFSection(".debug_info",
685                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
686                         COFF::IMAGE_SCN_MEM_READ,
687                         SectionKind::getMetadata());
688   DwarfLineSection =
689     Ctx->getCOFFSection(".debug_line",
690                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
691                         COFF::IMAGE_SCN_MEM_READ,
692                         SectionKind::getMetadata());
693   DwarfFrameSection =
694     Ctx->getCOFFSection(".debug_frame",
695                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
696                         COFF::IMAGE_SCN_MEM_READ,
697                         SectionKind::getMetadata());
698   DwarfPubNamesSection =
699     Ctx->getCOFFSection(".debug_pubnames",
700                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
701                         COFF::IMAGE_SCN_MEM_READ,
702                         SectionKind::getMetadata());
703   DwarfPubTypesSection =
704     Ctx->getCOFFSection(".debug_pubtypes",
705                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
706                         COFF::IMAGE_SCN_MEM_READ,
707                         SectionKind::getMetadata());
708   DwarfGnuPubNamesSection =
709     Ctx->getCOFFSection(".debug_gnu_pubnames",
710                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
711                         COFF::IMAGE_SCN_MEM_READ,
712                         SectionKind::getMetadata());
713   DwarfGnuPubTypesSection =
714     Ctx->getCOFFSection(".debug_gnu_pubtypes",
715                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
716                         COFF::IMAGE_SCN_MEM_READ,
717                         SectionKind::getMetadata());
718   DwarfStrSection =
719     Ctx->getCOFFSection(".debug_str",
720                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
721                         COFF::IMAGE_SCN_MEM_READ,
722                         SectionKind::getMetadata());
723   DwarfLocSection =
724     Ctx->getCOFFSection(".debug_loc",
725                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
726                         COFF::IMAGE_SCN_MEM_READ,
727                         SectionKind::getMetadata());
728   DwarfARangesSection =
729     Ctx->getCOFFSection(".debug_aranges",
730                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
731                         COFF::IMAGE_SCN_MEM_READ,
732                         SectionKind::getMetadata());
733   DwarfRangesSection =
734     Ctx->getCOFFSection(".debug_ranges",
735                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
736                         COFF::IMAGE_SCN_MEM_READ,
737                         SectionKind::getMetadata());
738   DwarfMacroInfoSection =
739     Ctx->getCOFFSection(".debug_macinfo",
740                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
741                         COFF::IMAGE_SCN_MEM_READ,
742                         SectionKind::getMetadata());
743   DwarfInfoDWOSection =
744       Ctx->getCOFFSection(".debug_info.dwo",
745                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
746                           COFF::IMAGE_SCN_MEM_READ,
747                           SectionKind::getMetadata());
748   DwarfTypesDWOSection =
749       Ctx->getCOFFSection(".debug_types.dwo", COFF::IMAGE_SCN_MEM_DISCARDABLE |
750                                                   COFF::IMAGE_SCN_MEM_READ,
751                           SectionKind::getMetadata());
752   DwarfAbbrevDWOSection =
753       Ctx->getCOFFSection(".debug_abbrev.dwo",
754                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
755                           COFF::IMAGE_SCN_MEM_READ,
756                           SectionKind::getMetadata());
757   DwarfStrDWOSection =
758       Ctx->getCOFFSection(".debug_str.dwo",
759                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
760                           COFF::IMAGE_SCN_MEM_READ,
761                           SectionKind::getMetadata());
762   DwarfLineDWOSection =
763       Ctx->getCOFFSection(".debug_line.dwo",
764                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
765                           COFF::IMAGE_SCN_MEM_READ,
766                           SectionKind::getMetadata());
767   DwarfLocDWOSection =
768       Ctx->getCOFFSection(".debug_loc.dwo",
769                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
770                           COFF::IMAGE_SCN_MEM_READ,
771                           SectionKind::getMetadata());
772   DwarfStrOffDWOSection =
773       Ctx->getCOFFSection(".debug_str_offsets.dwo",
774                           COFF::IMAGE_SCN_MEM_DISCARDABLE |
775                           COFF::IMAGE_SCN_MEM_READ,
776                           SectionKind::getMetadata());
777 
778   DwarfAddrSection =
779     Ctx->getCOFFSection(".debug_addr",
780                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
781                         COFF::IMAGE_SCN_MEM_READ,
782                         SectionKind::getMetadata());
783 
784   DrectveSection =
785     Ctx->getCOFFSection(".drectve",
786                         COFF::IMAGE_SCN_LNK_INFO |
787                         COFF::IMAGE_SCN_LNK_REMOVE,
788                         SectionKind::getMetadata());
789 
790   PDataSection =
791     Ctx->getCOFFSection(".pdata",
792                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
793                         COFF::IMAGE_SCN_MEM_READ,
794                         SectionKind::getDataRel());
795 
796   XDataSection =
797     Ctx->getCOFFSection(".xdata",
798                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
799                         COFF::IMAGE_SCN_MEM_READ,
800                         SectionKind::getDataRel());
801 
802   TLSDataSection =
803     Ctx->getCOFFSection(".tls$",
804                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
805                         COFF::IMAGE_SCN_MEM_READ |
806                         COFF::IMAGE_SCN_MEM_WRITE,
807                         SectionKind::getDataRel());
808 }
809 
810 void MCObjectFileInfo::InitMCObjectFileInfo(StringRef T, Reloc::Model relocm,
811                                             CodeModel::Model cm,
812                                             MCContext &ctx) {
813   RelocM = relocm;
814   CMModel = cm;
815   Ctx = &ctx;
816 
817   // Common.
818   CommDirectiveSupportsAlignment = true;
819   SupportsWeakOmittedEHFrame = true;
820   SupportsCompactUnwindWithoutEHFrame = false;
821 
822   PersonalityEncoding = LSDAEncoding = FDECFIEncoding = TTypeEncoding =
823       dwarf::DW_EH_PE_absptr;
824 
825   CompactUnwindDwarfEHFrameOnly = 0;
826 
827   EHFrameSection = nullptr;             // Created on demand.
828   CompactUnwindSection = nullptr;       // Used only by selected targets.
829   DwarfAccelNamesSection = nullptr;     // Used only by selected targets.
830   DwarfAccelObjCSection = nullptr;      // Used only by selected targets.
831   DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
832   DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
833 
834   TT = Triple(T);
835 
836   Triple::ArchType Arch = TT.getArch();
837   // FIXME: Checking for Arch here to filter out bogus triples such as
838   // cellspu-apple-darwin. Perhaps we should fix in Triple?
839   if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
840        Arch == Triple::arm || Arch == Triple::thumb ||
841        Arch == Triple::aarch64 ||
842        Arch == Triple::ppc || Arch == Triple::ppc64 ||
843        Arch == Triple::UnknownArch) &&
844       (TT.isOSDarwin() || TT.isOSBinFormatMachO())) {
845     Env = IsMachO;
846     InitMachOMCObjectFileInfo(TT);
847   } else if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
848               Arch == Triple::arm || Arch == Triple::thumb) &&
849              (TT.isOSWindows() && TT.getObjectFormat() == Triple::COFF)) {
850     Env = IsCOFF;
851     InitCOFFMCObjectFileInfo(TT);
852   } else {
853     Env = IsELF;
854     InitELFMCObjectFileInfo(TT);
855   }
856 }
857 
858 const MCSection *MCObjectFileInfo::getDwarfTypesSection(uint64_t Hash) const {
859   return Ctx->getELFSection(".debug_types", ELF::SHT_PROGBITS, ELF::SHF_GROUP,
860                             SectionKind::getMetadata(), 0, utostr(Hash));
861 }
862 
863 void MCObjectFileInfo::InitEHFrameSection() {
864   if (Env == IsMachO)
865     EHFrameSection =
866       Ctx->getMachOSection("__TEXT", "__eh_frame",
867                            MachO::S_COALESCED |
868                            MachO::S_ATTR_NO_TOC |
869                            MachO::S_ATTR_STRIP_STATIC_SYMS |
870                            MachO::S_ATTR_LIVE_SUPPORT,
871                            SectionKind::getReadOnly());
872   else if (Env == IsELF)
873     EHFrameSection =
874       Ctx->getELFSection(".eh_frame", EHSectionType,
875                          EHSectionFlags,
876                          SectionKind::getDataRel());
877   else
878     EHFrameSection =
879       Ctx->getCOFFSection(".eh_frame",
880                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
881                           COFF::IMAGE_SCN_MEM_READ |
882                           COFF::IMAGE_SCN_MEM_WRITE,
883                           SectionKind::getDataRel());
884 }
885