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/MC/MCContext.h"
12 #include "llvm/MC/MCSection.h"
13 #include "llvm/MC/MCSectionCOFF.h"
14 #include "llvm/MC/MCSectionELF.h"
15 #include "llvm/MC/MCSectionMachO.h"
16 #include "llvm/ADT/Triple.h"
17 using namespace llvm;
18 
19 void MCObjectFileInfo::InitMachOMCObjectFileInfo(Triple T) {
20   // MachO
21   IsFunctionEHFrameSymbolPrivate = false;
22   SupportsWeakOmittedEHFrame = false;
23 
24   PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel
25     | dwarf::DW_EH_PE_sdata4;
26   LSDAEncoding = FDEEncoding = FDECFIEncoding = dwarf::DW_EH_PE_pcrel;
27   TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
28     dwarf::DW_EH_PE_sdata4;
29 
30   // .comm doesn't support alignment before Leopard.
31   if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
32     CommDirectiveSupportsAlignment = false;
33 
34   TextSection // .text
35     = Ctx->getMachOSection("__TEXT", "__text",
36                            MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
37                            SectionKind::getText());
38   DataSection // .data
39     = Ctx->getMachOSection("__DATA", "__data", 0,
40                            SectionKind::getDataRel());
41 
42   TLSDataSection // .tdata
43     = Ctx->getMachOSection("__DATA", "__thread_data",
44                            MCSectionMachO::S_THREAD_LOCAL_REGULAR,
45                            SectionKind::getDataRel());
46   TLSBSSSection // .tbss
47     = Ctx->getMachOSection("__DATA", "__thread_bss",
48                            MCSectionMachO::S_THREAD_LOCAL_ZEROFILL,
49                            SectionKind::getThreadBSS());
50 
51   // TODO: Verify datarel below.
52   TLSTLVSection // .tlv
53     = Ctx->getMachOSection("__DATA", "__thread_vars",
54                            MCSectionMachO::S_THREAD_LOCAL_VARIABLES,
55                            SectionKind::getDataRel());
56 
57   TLSThreadInitSection
58     = Ctx->getMachOSection("__DATA", "__thread_init",
59                           MCSectionMachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
60                           SectionKind::getDataRel());
61 
62   CStringSection // .cstring
63     = Ctx->getMachOSection("__TEXT", "__cstring",
64                            MCSectionMachO::S_CSTRING_LITERALS,
65                            SectionKind::getMergeable1ByteCString());
66   UStringSection
67     = Ctx->getMachOSection("__TEXT","__ustring", 0,
68                            SectionKind::getMergeable2ByteCString());
69   FourByteConstantSection // .literal4
70     = Ctx->getMachOSection("__TEXT", "__literal4",
71                            MCSectionMachO::S_4BYTE_LITERALS,
72                            SectionKind::getMergeableConst4());
73   EightByteConstantSection // .literal8
74     = Ctx->getMachOSection("__TEXT", "__literal8",
75                            MCSectionMachO::S_8BYTE_LITERALS,
76                            SectionKind::getMergeableConst8());
77 
78   // ld_classic doesn't support .literal16 in 32-bit mode, and ld64 falls back
79   // to using it in -static mode.
80   SixteenByteConstantSection = 0;
81   if (RelocM != Reloc::Static &&
82       T.getArch() != Triple::x86_64 && T.getArch() != Triple::ppc64)
83     SixteenByteConstantSection =   // .literal16
84       Ctx->getMachOSection("__TEXT", "__literal16",
85                            MCSectionMachO::S_16BYTE_LITERALS,
86                            SectionKind::getMergeableConst16());
87 
88   ReadOnlySection  // .const
89     = Ctx->getMachOSection("__TEXT", "__const", 0,
90                            SectionKind::getReadOnly());
91 
92   TextCoalSection
93     = Ctx->getMachOSection("__TEXT", "__textcoal_nt",
94                            MCSectionMachO::S_COALESCED |
95                            MCSectionMachO::S_ATTR_PURE_INSTRUCTIONS,
96                            SectionKind::getText());
97   ConstTextCoalSection
98     = Ctx->getMachOSection("__TEXT", "__const_coal",
99                            MCSectionMachO::S_COALESCED,
100                            SectionKind::getReadOnly());
101   ConstDataSection  // .const_data
102     = Ctx->getMachOSection("__DATA", "__const", 0,
103                            SectionKind::getReadOnlyWithRel());
104   DataCoalSection
105     = Ctx->getMachOSection("__DATA","__datacoal_nt",
106                            MCSectionMachO::S_COALESCED,
107                            SectionKind::getDataRel());
108   DataCommonSection
109     = Ctx->getMachOSection("__DATA","__common",
110                            MCSectionMachO::S_ZEROFILL,
111                            SectionKind::getBSS());
112   DataBSSSection
113     = Ctx->getMachOSection("__DATA","__bss", MCSectionMachO::S_ZEROFILL,
114                            SectionKind::getBSS());
115 
116 
117   LazySymbolPointerSection
118     = Ctx->getMachOSection("__DATA", "__la_symbol_ptr",
119                            MCSectionMachO::S_LAZY_SYMBOL_POINTERS,
120                            SectionKind::getMetadata());
121   NonLazySymbolPointerSection
122     = Ctx->getMachOSection("__DATA", "__nl_symbol_ptr",
123                            MCSectionMachO::S_NON_LAZY_SYMBOL_POINTERS,
124                            SectionKind::getMetadata());
125 
126   if (RelocM == Reloc::Static) {
127     StaticCtorSection
128       = Ctx->getMachOSection("__TEXT", "__constructor", 0,
129                              SectionKind::getDataRel());
130     StaticDtorSection
131       = Ctx->getMachOSection("__TEXT", "__destructor", 0,
132                              SectionKind::getDataRel());
133   } else {
134     StaticCtorSection
135       = Ctx->getMachOSection("__DATA", "__mod_init_func",
136                              MCSectionMachO::S_MOD_INIT_FUNC_POINTERS,
137                              SectionKind::getDataRel());
138     StaticDtorSection
139       = Ctx->getMachOSection("__DATA", "__mod_term_func",
140                              MCSectionMachO::S_MOD_TERM_FUNC_POINTERS,
141                              SectionKind::getDataRel());
142   }
143 
144   // Exception Handling.
145   LSDASection = Ctx->getMachOSection("__TEXT", "__gcc_except_tab", 0,
146                                      SectionKind::getReadOnlyWithRel());
147 
148   if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6))
149     CompactUnwindSection =
150       Ctx->getMachOSection("__LD", "__compact_unwind",
151                            MCSectionMachO::S_ATTR_DEBUG,
152                            SectionKind::getReadOnly());
153 
154   // Debug Information.
155   DwarfAccelNamesSection =
156     Ctx->getMachOSection("__DWARF", "__apple_names",
157                          MCSectionMachO::S_ATTR_DEBUG,
158                          SectionKind::getMetadata());
159   DwarfAccelObjCSection =
160     Ctx->getMachOSection("__DWARF", "__apple_objc",
161                          MCSectionMachO::S_ATTR_DEBUG,
162                          SectionKind::getMetadata());
163   // 16 character section limit...
164   DwarfAccelNamespaceSection =
165     Ctx->getMachOSection("__DWARF", "__apple_namespac",
166                          MCSectionMachO::S_ATTR_DEBUG,
167                          SectionKind::getMetadata());
168   DwarfAccelTypesSection =
169     Ctx->getMachOSection("__DWARF", "__apple_types",
170                          MCSectionMachO::S_ATTR_DEBUG,
171                          SectionKind::getMetadata());
172 
173   DwarfAbbrevSection =
174     Ctx->getMachOSection("__DWARF", "__debug_abbrev",
175                          MCSectionMachO::S_ATTR_DEBUG,
176                          SectionKind::getMetadata());
177   DwarfInfoSection =
178     Ctx->getMachOSection("__DWARF", "__debug_info",
179                          MCSectionMachO::S_ATTR_DEBUG,
180                          SectionKind::getMetadata());
181   DwarfLineSection =
182     Ctx->getMachOSection("__DWARF", "__debug_line",
183                          MCSectionMachO::S_ATTR_DEBUG,
184                          SectionKind::getMetadata());
185   DwarfFrameSection =
186     Ctx->getMachOSection("__DWARF", "__debug_frame",
187                          MCSectionMachO::S_ATTR_DEBUG,
188                          SectionKind::getMetadata());
189   DwarfPubTypesSection =
190     Ctx->getMachOSection("__DWARF", "__debug_pubtypes",
191                          MCSectionMachO::S_ATTR_DEBUG,
192                          SectionKind::getMetadata());
193   DwarfStrSection =
194     Ctx->getMachOSection("__DWARF", "__debug_str",
195                          MCSectionMachO::S_ATTR_DEBUG,
196                          SectionKind::getMetadata());
197   DwarfLocSection =
198     Ctx->getMachOSection("__DWARF", "__debug_loc",
199                          MCSectionMachO::S_ATTR_DEBUG,
200                          SectionKind::getMetadata());
201   DwarfARangesSection =
202     Ctx->getMachOSection("__DWARF", "__debug_aranges",
203                          MCSectionMachO::S_ATTR_DEBUG,
204                          SectionKind::getMetadata());
205   DwarfRangesSection =
206     Ctx->getMachOSection("__DWARF", "__debug_ranges",
207                          MCSectionMachO::S_ATTR_DEBUG,
208                          SectionKind::getMetadata());
209   DwarfMacroInfoSection =
210     Ctx->getMachOSection("__DWARF", "__debug_macinfo",
211                          MCSectionMachO::S_ATTR_DEBUG,
212                          SectionKind::getMetadata());
213   DwarfDebugInlineSection =
214     Ctx->getMachOSection("__DWARF", "__debug_inlined",
215                          MCSectionMachO::S_ATTR_DEBUG,
216                          SectionKind::getMetadata());
217 
218   TLSExtraDataSection = TLSTLVSection;
219 }
220 
221 void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
222   if (T.getArch() == Triple::x86) {
223     PersonalityEncoding = (RelocM == Reloc::PIC_)
224      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
225      : dwarf::DW_EH_PE_absptr;
226     LSDAEncoding = (RelocM == Reloc::PIC_)
227       ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
228       : dwarf::DW_EH_PE_absptr;
229     FDEEncoding = FDECFIEncoding = (RelocM == Reloc::PIC_)
230       ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
231       : dwarf::DW_EH_PE_absptr;
232     TTypeEncoding = (RelocM == Reloc::PIC_)
233      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
234      : dwarf::DW_EH_PE_absptr;
235   } else if (T.getArch() == Triple::x86_64) {
236     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
237 
238     if (RelocM == Reloc::PIC_) {
239       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
240         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
241          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
242       LSDAEncoding = dwarf::DW_EH_PE_pcrel |
243         (CMModel == CodeModel::Small
244          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
245       FDEEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
246       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
247         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
248          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
249     } else {
250       PersonalityEncoding =
251         (CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
252         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
253       LSDAEncoding = (CMModel == CodeModel::Small)
254         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
255       FDEEncoding = dwarf::DW_EH_PE_udata4;
256       TTypeEncoding = (CMModel == CodeModel::Small)
257         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
258     }
259   }
260 
261   // ELF
262   BSSSection =
263     Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
264                        ELF::SHF_WRITE | ELF::SHF_ALLOC,
265                        SectionKind::getBSS());
266 
267   TextSection =
268     Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
269                        ELF::SHF_EXECINSTR |
270                        ELF::SHF_ALLOC,
271                        SectionKind::getText());
272 
273   DataSection =
274     Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
275                        ELF::SHF_WRITE |ELF::SHF_ALLOC,
276                        SectionKind::getDataRel());
277 
278   ReadOnlySection =
279     Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS,
280                        ELF::SHF_ALLOC,
281                        SectionKind::getReadOnly());
282 
283   TLSDataSection =
284     Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
285                        ELF::SHF_ALLOC | ELF::SHF_TLS |
286                        ELF::SHF_WRITE,
287                        SectionKind::getThreadData());
288 
289   TLSBSSSection =
290     Ctx->getELFSection(".tbss", ELF::SHT_NOBITS,
291                        ELF::SHF_ALLOC | ELF::SHF_TLS |
292                        ELF::SHF_WRITE,
293                        SectionKind::getThreadBSS());
294 
295   DataRelSection =
296     Ctx->getELFSection(".data.rel", ELF::SHT_PROGBITS,
297                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
298                        SectionKind::getDataRel());
299 
300   DataRelLocalSection =
301     Ctx->getELFSection(".data.rel.local", ELF::SHT_PROGBITS,
302                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
303                        SectionKind::getDataRelLocal());
304 
305   DataRelROSection =
306     Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
307                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
308                        SectionKind::getReadOnlyWithRel());
309 
310   DataRelROLocalSection =
311     Ctx->getELFSection(".data.rel.ro.local", ELF::SHT_PROGBITS,
312                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
313                        SectionKind::getReadOnlyWithRelLocal());
314 
315   MergeableConst4Section =
316     Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
317                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
318                        SectionKind::getMergeableConst4());
319 
320   MergeableConst8Section =
321     Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
322                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
323                        SectionKind::getMergeableConst8());
324 
325   MergeableConst16Section =
326     Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
327                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
328                        SectionKind::getMergeableConst16());
329 
330   StaticCtorSection =
331     Ctx->getELFSection(".ctors", ELF::SHT_PROGBITS,
332                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
333                        SectionKind::getDataRel());
334 
335   StaticDtorSection =
336     Ctx->getELFSection(".dtors", ELF::SHT_PROGBITS,
337                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
338                        SectionKind::getDataRel());
339 
340   // Exception Handling Sections.
341 
342   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
343   // it contains relocatable pointers.  In PIC mode, this is probably a big
344   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
345   // adjusted or this should be a data section.
346   LSDASection =
347     Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
348                        ELF::SHF_ALLOC,
349                        SectionKind::getReadOnly());
350 
351   // Debug Info Sections.
352   DwarfAbbrevSection =
353     Ctx->getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0,
354                        SectionKind::getMetadata());
355   DwarfInfoSection =
356     Ctx->getELFSection(".debug_info", ELF::SHT_PROGBITS, 0,
357                        SectionKind::getMetadata());
358   DwarfLineSection =
359     Ctx->getELFSection(".debug_line", ELF::SHT_PROGBITS, 0,
360                        SectionKind::getMetadata());
361   DwarfFrameSection =
362     Ctx->getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0,
363                        SectionKind::getMetadata());
364   DwarfPubTypesSection =
365     Ctx->getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0,
366                        SectionKind::getMetadata());
367   DwarfStrSection =
368     Ctx->getELFSection(".debug_str", ELF::SHT_PROGBITS,
369                        ELF::SHF_MERGE | ELF::SHF_STRINGS,
370                        SectionKind::getMergeable1ByteCString());
371   DwarfLocSection =
372     Ctx->getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0,
373                        SectionKind::getMetadata());
374   DwarfARangesSection =
375     Ctx->getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0,
376                        SectionKind::getMetadata());
377   DwarfRangesSection =
378     Ctx->getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0,
379                        SectionKind::getMetadata());
380   DwarfMacroInfoSection =
381     Ctx->getELFSection(".debug_macinfo", ELF::SHT_PROGBITS, 0,
382                        SectionKind::getMetadata());
383 }
384 
385 
386 void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
387   // COFF
388   TextSection =
389     Ctx->getCOFFSection(".text",
390                         COFF::IMAGE_SCN_CNT_CODE |
391                         COFF::IMAGE_SCN_MEM_EXECUTE |
392                         COFF::IMAGE_SCN_MEM_READ,
393                         SectionKind::getText());
394   DataSection =
395     Ctx->getCOFFSection(".data",
396                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
397                         COFF::IMAGE_SCN_MEM_READ |
398                         COFF::IMAGE_SCN_MEM_WRITE,
399                         SectionKind::getDataRel());
400   ReadOnlySection =
401     Ctx->getCOFFSection(".rdata",
402                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
403                         COFF::IMAGE_SCN_MEM_READ,
404                         SectionKind::getReadOnly());
405   StaticCtorSection =
406     Ctx->getCOFFSection(".ctors",
407                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
408                         COFF::IMAGE_SCN_MEM_READ |
409                         COFF::IMAGE_SCN_MEM_WRITE,
410                         SectionKind::getDataRel());
411   StaticDtorSection =
412     Ctx->getCOFFSection(".dtors",
413                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
414                         COFF::IMAGE_SCN_MEM_READ |
415                         COFF::IMAGE_SCN_MEM_WRITE,
416                         SectionKind::getDataRel());
417 
418   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
419   // though it contains relocatable pointers.  In PIC mode, this is probably a
420   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
421   // adjusted or this should be a data section.
422   LSDASection =
423     Ctx->getCOFFSection(".gcc_except_table",
424                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
425                         COFF::IMAGE_SCN_MEM_READ,
426                         SectionKind::getReadOnly());
427 
428   // Debug info.
429   DwarfAbbrevSection =
430     Ctx->getCOFFSection(".debug_abbrev",
431                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
432                         COFF::IMAGE_SCN_MEM_READ,
433                         SectionKind::getMetadata());
434   DwarfInfoSection =
435     Ctx->getCOFFSection(".debug_info",
436                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
437                         COFF::IMAGE_SCN_MEM_READ,
438                         SectionKind::getMetadata());
439   DwarfLineSection =
440     Ctx->getCOFFSection(".debug_line",
441                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
442                         COFF::IMAGE_SCN_MEM_READ,
443                         SectionKind::getMetadata());
444   DwarfFrameSection =
445     Ctx->getCOFFSection(".debug_frame",
446                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
447                         COFF::IMAGE_SCN_MEM_READ,
448                         SectionKind::getMetadata());
449   DwarfPubTypesSection =
450     Ctx->getCOFFSection(".debug_pubtypes",
451                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
452                         COFF::IMAGE_SCN_MEM_READ,
453                         SectionKind::getMetadata());
454   DwarfStrSection =
455     Ctx->getCOFFSection(".debug_str",
456                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
457                         COFF::IMAGE_SCN_MEM_READ,
458                         SectionKind::getMetadata());
459   DwarfLocSection =
460     Ctx->getCOFFSection(".debug_loc",
461                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
462                         COFF::IMAGE_SCN_MEM_READ,
463                         SectionKind::getMetadata());
464   DwarfARangesSection =
465     Ctx->getCOFFSection(".debug_aranges",
466                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
467                         COFF::IMAGE_SCN_MEM_READ,
468                         SectionKind::getMetadata());
469   DwarfRangesSection =
470     Ctx->getCOFFSection(".debug_ranges",
471                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
472                         COFF::IMAGE_SCN_MEM_READ,
473                         SectionKind::getMetadata());
474   DwarfMacroInfoSection =
475     Ctx->getCOFFSection(".debug_macinfo",
476                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
477                         COFF::IMAGE_SCN_MEM_READ,
478                         SectionKind::getMetadata());
479 
480   DrectveSection =
481     Ctx->getCOFFSection(".drectve",
482                         COFF::IMAGE_SCN_LNK_INFO,
483                         SectionKind::getMetadata());
484 
485   PDataSection =
486     Ctx->getCOFFSection(".pdata",
487                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
488                         COFF::IMAGE_SCN_MEM_READ |
489                         COFF::IMAGE_SCN_MEM_WRITE,
490                         SectionKind::getDataRel());
491 
492   XDataSection =
493     Ctx->getCOFFSection(".xdata",
494                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
495                         COFF::IMAGE_SCN_MEM_READ |
496                         COFF::IMAGE_SCN_MEM_WRITE,
497                         SectionKind::getDataRel());
498 }
499 
500 void MCObjectFileInfo::InitMCObjectFileInfo(StringRef TT, Reloc::Model relocm,
501                                             CodeModel::Model cm,
502                                             MCContext &ctx) {
503   RelocM = relocm;
504   CMModel = cm;
505   Ctx = &ctx;
506 
507   // Common.
508   CommDirectiveSupportsAlignment = true;
509   SupportsWeakOmittedEHFrame = true;
510   IsFunctionEHFrameSymbolPrivate = true;
511 
512   PersonalityEncoding = LSDAEncoding = FDEEncoding = FDECFIEncoding =
513     TTypeEncoding = dwarf::DW_EH_PE_absptr;
514 
515   EHFrameSection = 0;             // Created on demand.
516   CompactUnwindSection = 0;       // Used only by selected targets.
517   DwarfAccelNamesSection = 0;     // Used only by selected targets.
518   DwarfAccelObjCSection = 0;      // Used only by selected targets.
519   DwarfAccelNamespaceSection = 0; // Used only by selected targets.
520   DwarfAccelTypesSection = 0;     // Used only by selected targets.
521 
522   Triple T(TT);
523   Triple::ArchType Arch = T.getArch();
524   // FIXME: Checking for Arch here to filter out bogus triples such as
525   // cellspu-apple-darwin. Perhaps we should fix in Triple?
526   if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
527        Arch == Triple::arm || Arch == Triple::thumb ||
528        Arch == Triple::ppc || Arch == Triple::ppc64 ||
529        Arch == Triple::UnknownArch) &&
530       (T.isOSDarwin() || T.getEnvironment() == Triple::MachO)) {
531     Env = IsMachO;
532     InitMachOMCObjectFileInfo(T);
533   } else if ((Arch == Triple::x86 || Arch == Triple::x86_64) &&
534              (T.getOS() == Triple::MinGW32 || T.getOS() == Triple::Cygwin ||
535               T.getOS() == Triple::Win32)) {
536     Env = IsCOFF;
537     InitCOFFMCObjectFileInfo(T);
538   } else {
539     Env = IsELF;
540     InitELFMCObjectFileInfo(T);
541   }
542 }
543 
544 void MCObjectFileInfo::InitEHFrameSection() {
545   if (Env == IsMachO)
546     EHFrameSection =
547       Ctx->getMachOSection("__TEXT", "__eh_frame",
548                            MCSectionMachO::S_COALESCED |
549                            MCSectionMachO::S_ATTR_NO_TOC |
550                            MCSectionMachO::S_ATTR_STRIP_STATIC_SYMS |
551                            MCSectionMachO::S_ATTR_LIVE_SUPPORT,
552                            SectionKind::getReadOnly());
553   else if (Env == IsELF)
554     EHFrameSection =
555       Ctx->getELFSection(".eh_frame", ELF::SHT_PROGBITS,
556                          ELF::SHF_ALLOC,
557                          SectionKind::getDataRel());
558   else
559     EHFrameSection =
560       Ctx->getCOFFSection(".eh_frame",
561                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
562                           COFF::IMAGE_SCN_MEM_READ |
563                           COFF::IMAGE_SCN_MEM_WRITE,
564                           SectionKind::getDataRel());
565 }
566