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   // Solaris requires different flags for .eh_frame to seemingly every other
262   // platform.
263   EHSectionFlags = ELF::SHF_ALLOC;
264   if (T.getOS() == Triple::Solaris)
265     EHSectionFlags |= ELF::SHF_WRITE;
266 
267 
268   // ELF
269   BSSSection =
270     Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
271                        ELF::SHF_WRITE | ELF::SHF_ALLOC,
272                        SectionKind::getBSS());
273 
274   TextSection =
275     Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
276                        ELF::SHF_EXECINSTR |
277                        ELF::SHF_ALLOC,
278                        SectionKind::getText());
279 
280   DataSection =
281     Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
282                        ELF::SHF_WRITE |ELF::SHF_ALLOC,
283                        SectionKind::getDataRel());
284 
285   ReadOnlySection =
286     Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS,
287                        ELF::SHF_ALLOC,
288                        SectionKind::getReadOnly());
289 
290   TLSDataSection =
291     Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
292                        ELF::SHF_ALLOC | ELF::SHF_TLS |
293                        ELF::SHF_WRITE,
294                        SectionKind::getThreadData());
295 
296   TLSBSSSection =
297     Ctx->getELFSection(".tbss", ELF::SHT_NOBITS,
298                        ELF::SHF_ALLOC | ELF::SHF_TLS |
299                        ELF::SHF_WRITE,
300                        SectionKind::getThreadBSS());
301 
302   DataRelSection =
303     Ctx->getELFSection(".data.rel", ELF::SHT_PROGBITS,
304                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
305                        SectionKind::getDataRel());
306 
307   DataRelLocalSection =
308     Ctx->getELFSection(".data.rel.local", ELF::SHT_PROGBITS,
309                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
310                        SectionKind::getDataRelLocal());
311 
312   DataRelROSection =
313     Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
314                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
315                        SectionKind::getReadOnlyWithRel());
316 
317   DataRelROLocalSection =
318     Ctx->getELFSection(".data.rel.ro.local", ELF::SHT_PROGBITS,
319                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
320                        SectionKind::getReadOnlyWithRelLocal());
321 
322   MergeableConst4Section =
323     Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
324                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
325                        SectionKind::getMergeableConst4());
326 
327   MergeableConst8Section =
328     Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
329                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
330                        SectionKind::getMergeableConst8());
331 
332   MergeableConst16Section =
333     Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
334                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
335                        SectionKind::getMergeableConst16());
336 
337   StaticCtorSection =
338     Ctx->getELFSection(".ctors", ELF::SHT_PROGBITS,
339                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
340                        SectionKind::getDataRel());
341 
342   StaticDtorSection =
343     Ctx->getELFSection(".dtors", ELF::SHT_PROGBITS,
344                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
345                        SectionKind::getDataRel());
346 
347   // Exception Handling Sections.
348 
349   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
350   // it contains relocatable pointers.  In PIC mode, this is probably a big
351   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
352   // adjusted or this should be a data section.
353   LSDASection =
354     Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
355                        ELF::SHF_ALLOC,
356                        SectionKind::getReadOnly());
357 
358   // Debug Info Sections.
359   DwarfAbbrevSection =
360     Ctx->getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0,
361                        SectionKind::getMetadata());
362   DwarfInfoSection =
363     Ctx->getELFSection(".debug_info", ELF::SHT_PROGBITS, 0,
364                        SectionKind::getMetadata());
365   DwarfLineSection =
366     Ctx->getELFSection(".debug_line", ELF::SHT_PROGBITS, 0,
367                        SectionKind::getMetadata());
368   DwarfFrameSection =
369     Ctx->getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0,
370                        SectionKind::getMetadata());
371   DwarfPubTypesSection =
372     Ctx->getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0,
373                        SectionKind::getMetadata());
374   DwarfStrSection =
375     Ctx->getELFSection(".debug_str", ELF::SHT_PROGBITS,
376                        ELF::SHF_MERGE | ELF::SHF_STRINGS,
377                        SectionKind::getMergeable1ByteCString());
378   DwarfLocSection =
379     Ctx->getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0,
380                        SectionKind::getMetadata());
381   DwarfARangesSection =
382     Ctx->getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0,
383                        SectionKind::getMetadata());
384   DwarfRangesSection =
385     Ctx->getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0,
386                        SectionKind::getMetadata());
387   DwarfMacroInfoSection =
388     Ctx->getELFSection(".debug_macinfo", ELF::SHT_PROGBITS, 0,
389                        SectionKind::getMetadata());
390 }
391 
392 
393 void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
394   // COFF
395   TextSection =
396     Ctx->getCOFFSection(".text",
397                         COFF::IMAGE_SCN_CNT_CODE |
398                         COFF::IMAGE_SCN_MEM_EXECUTE |
399                         COFF::IMAGE_SCN_MEM_READ,
400                         SectionKind::getText());
401   DataSection =
402     Ctx->getCOFFSection(".data",
403                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
404                         COFF::IMAGE_SCN_MEM_READ |
405                         COFF::IMAGE_SCN_MEM_WRITE,
406                         SectionKind::getDataRel());
407   ReadOnlySection =
408     Ctx->getCOFFSection(".rdata",
409                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
410                         COFF::IMAGE_SCN_MEM_READ,
411                         SectionKind::getReadOnly());
412   StaticCtorSection =
413     Ctx->getCOFFSection(".ctors",
414                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
415                         COFF::IMAGE_SCN_MEM_READ |
416                         COFF::IMAGE_SCN_MEM_WRITE,
417                         SectionKind::getDataRel());
418   StaticDtorSection =
419     Ctx->getCOFFSection(".dtors",
420                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
421                         COFF::IMAGE_SCN_MEM_READ |
422                         COFF::IMAGE_SCN_MEM_WRITE,
423                         SectionKind::getDataRel());
424 
425   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
426   // though it contains relocatable pointers.  In PIC mode, this is probably a
427   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
428   // adjusted or this should be a data section.
429   LSDASection =
430     Ctx->getCOFFSection(".gcc_except_table",
431                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
432                         COFF::IMAGE_SCN_MEM_READ,
433                         SectionKind::getReadOnly());
434 
435   // Debug info.
436   DwarfAbbrevSection =
437     Ctx->getCOFFSection(".debug_abbrev",
438                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
439                         COFF::IMAGE_SCN_MEM_READ,
440                         SectionKind::getMetadata());
441   DwarfInfoSection =
442     Ctx->getCOFFSection(".debug_info",
443                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
444                         COFF::IMAGE_SCN_MEM_READ,
445                         SectionKind::getMetadata());
446   DwarfLineSection =
447     Ctx->getCOFFSection(".debug_line",
448                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
449                         COFF::IMAGE_SCN_MEM_READ,
450                         SectionKind::getMetadata());
451   DwarfFrameSection =
452     Ctx->getCOFFSection(".debug_frame",
453                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
454                         COFF::IMAGE_SCN_MEM_READ,
455                         SectionKind::getMetadata());
456   DwarfPubTypesSection =
457     Ctx->getCOFFSection(".debug_pubtypes",
458                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
459                         COFF::IMAGE_SCN_MEM_READ,
460                         SectionKind::getMetadata());
461   DwarfStrSection =
462     Ctx->getCOFFSection(".debug_str",
463                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
464                         COFF::IMAGE_SCN_MEM_READ,
465                         SectionKind::getMetadata());
466   DwarfLocSection =
467     Ctx->getCOFFSection(".debug_loc",
468                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
469                         COFF::IMAGE_SCN_MEM_READ,
470                         SectionKind::getMetadata());
471   DwarfARangesSection =
472     Ctx->getCOFFSection(".debug_aranges",
473                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
474                         COFF::IMAGE_SCN_MEM_READ,
475                         SectionKind::getMetadata());
476   DwarfRangesSection =
477     Ctx->getCOFFSection(".debug_ranges",
478                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
479                         COFF::IMAGE_SCN_MEM_READ,
480                         SectionKind::getMetadata());
481   DwarfMacroInfoSection =
482     Ctx->getCOFFSection(".debug_macinfo",
483                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
484                         COFF::IMAGE_SCN_MEM_READ,
485                         SectionKind::getMetadata());
486 
487   DrectveSection =
488     Ctx->getCOFFSection(".drectve",
489                         COFF::IMAGE_SCN_LNK_INFO,
490                         SectionKind::getMetadata());
491 
492   PDataSection =
493     Ctx->getCOFFSection(".pdata",
494                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
495                         COFF::IMAGE_SCN_MEM_READ |
496                         COFF::IMAGE_SCN_MEM_WRITE,
497                         SectionKind::getDataRel());
498 
499   XDataSection =
500     Ctx->getCOFFSection(".xdata",
501                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
502                         COFF::IMAGE_SCN_MEM_READ |
503                         COFF::IMAGE_SCN_MEM_WRITE,
504                         SectionKind::getDataRel());
505   TLSDataSection =
506     Ctx->getCOFFSection(".tls$",
507                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
508                         COFF::IMAGE_SCN_MEM_READ |
509                         COFF::IMAGE_SCN_MEM_WRITE,
510                         SectionKind::getDataRel());
511 }
512 
513 void MCObjectFileInfo::InitMCObjectFileInfo(StringRef TT, Reloc::Model relocm,
514                                             CodeModel::Model cm,
515                                             MCContext &ctx) {
516   RelocM = relocm;
517   CMModel = cm;
518   Ctx = &ctx;
519 
520   // Common.
521   CommDirectiveSupportsAlignment = true;
522   SupportsWeakOmittedEHFrame = true;
523   IsFunctionEHFrameSymbolPrivate = true;
524 
525   PersonalityEncoding = LSDAEncoding = FDEEncoding = FDECFIEncoding =
526     TTypeEncoding = dwarf::DW_EH_PE_absptr;
527 
528   EHFrameSection = 0;             // Created on demand.
529   CompactUnwindSection = 0;       // Used only by selected targets.
530   DwarfAccelNamesSection = 0;     // Used only by selected targets.
531   DwarfAccelObjCSection = 0;      // Used only by selected targets.
532   DwarfAccelNamespaceSection = 0; // Used only by selected targets.
533   DwarfAccelTypesSection = 0;     // Used only by selected targets.
534 
535   Triple T(TT);
536   Triple::ArchType Arch = T.getArch();
537   // FIXME: Checking for Arch here to filter out bogus triples such as
538   // cellspu-apple-darwin. Perhaps we should fix in Triple?
539   if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
540        Arch == Triple::arm || Arch == Triple::thumb ||
541        Arch == Triple::ppc || Arch == Triple::ppc64 ||
542        Arch == Triple::UnknownArch) &&
543       (T.isOSDarwin() || T.getEnvironment() == Triple::MachO)) {
544     Env = IsMachO;
545     InitMachOMCObjectFileInfo(T);
546   } else if ((Arch == Triple::x86 || Arch == Triple::x86_64) &&
547              (T.getOS() == Triple::MinGW32 || T.getOS() == Triple::Cygwin ||
548               T.getOS() == Triple::Win32)) {
549     Env = IsCOFF;
550     InitCOFFMCObjectFileInfo(T);
551   } else {
552     Env = IsELF;
553     InitELFMCObjectFileInfo(T);
554   }
555 }
556 
557 void MCObjectFileInfo::InitEHFrameSection() {
558   if (Env == IsMachO)
559     EHFrameSection =
560       Ctx->getMachOSection("__TEXT", "__eh_frame",
561                            MCSectionMachO::S_COALESCED |
562                            MCSectionMachO::S_ATTR_NO_TOC |
563                            MCSectionMachO::S_ATTR_STRIP_STATIC_SYMS |
564                            MCSectionMachO::S_ATTR_LIVE_SUPPORT,
565                            SectionKind::getReadOnly());
566   else if (Env == IsELF)
567     EHFrameSection =
568       Ctx->getELFSection(".eh_frame", ELF::SHT_PROGBITS,
569                          EHSectionFlags,
570                          SectionKind::getDataRel());
571   else
572     EHFrameSection =
573       Ctx->getCOFFSection(".eh_frame",
574                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
575                           COFF::IMAGE_SCN_MEM_READ |
576                           COFF::IMAGE_SCN_MEM_WRITE,
577                           SectionKind::getDataRel());
578 }
579