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/Triple.h"
12 #include "llvm/MC/MCContext.h"
13 #include "llvm/MC/MCSection.h"
14 #include "llvm/MC/MCSectionCOFF.h"
15 #include "llvm/MC/MCSectionELF.h"
16 #include "llvm/MC/MCSectionMachO.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     if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86)
155       CompactUnwindDwarfEHFrameOnly = 0x04000000;
156   }
157 
158   // Debug Information.
159   DwarfAccelNamesSection =
160     Ctx->getMachOSection("__DWARF", "__apple_names",
161                          MCSectionMachO::S_ATTR_DEBUG,
162                          SectionKind::getMetadata());
163   DwarfAccelObjCSection =
164     Ctx->getMachOSection("__DWARF", "__apple_objc",
165                          MCSectionMachO::S_ATTR_DEBUG,
166                          SectionKind::getMetadata());
167   // 16 character section limit...
168   DwarfAccelNamespaceSection =
169     Ctx->getMachOSection("__DWARF", "__apple_namespac",
170                          MCSectionMachO::S_ATTR_DEBUG,
171                          SectionKind::getMetadata());
172   DwarfAccelTypesSection =
173     Ctx->getMachOSection("__DWARF", "__apple_types",
174                          MCSectionMachO::S_ATTR_DEBUG,
175                          SectionKind::getMetadata());
176 
177   DwarfAbbrevSection =
178     Ctx->getMachOSection("__DWARF", "__debug_abbrev",
179                          MCSectionMachO::S_ATTR_DEBUG,
180                          SectionKind::getMetadata());
181   DwarfInfoSection =
182     Ctx->getMachOSection("__DWARF", "__debug_info",
183                          MCSectionMachO::S_ATTR_DEBUG,
184                          SectionKind::getMetadata());
185   DwarfLineSection =
186     Ctx->getMachOSection("__DWARF", "__debug_line",
187                          MCSectionMachO::S_ATTR_DEBUG,
188                          SectionKind::getMetadata());
189   DwarfFrameSection =
190     Ctx->getMachOSection("__DWARF", "__debug_frame",
191                          MCSectionMachO::S_ATTR_DEBUG,
192                          SectionKind::getMetadata());
193   DwarfPubNamesSection =
194     Ctx->getMachOSection("__DWARF", "__debug_pubnames",
195                          MCSectionMachO::S_ATTR_DEBUG,
196                          SectionKind::getMetadata());
197   DwarfPubTypesSection =
198     Ctx->getMachOSection("__DWARF", "__debug_pubtypes",
199                          MCSectionMachO::S_ATTR_DEBUG,
200                          SectionKind::getMetadata());
201   DwarfStrSection =
202     Ctx->getMachOSection("__DWARF", "__debug_str",
203                          MCSectionMachO::S_ATTR_DEBUG,
204                          SectionKind::getMetadata());
205   DwarfLocSection =
206     Ctx->getMachOSection("__DWARF", "__debug_loc",
207                          MCSectionMachO::S_ATTR_DEBUG,
208                          SectionKind::getMetadata());
209   DwarfARangesSection =
210     Ctx->getMachOSection("__DWARF", "__debug_aranges",
211                          MCSectionMachO::S_ATTR_DEBUG,
212                          SectionKind::getMetadata());
213   DwarfRangesSection =
214     Ctx->getMachOSection("__DWARF", "__debug_ranges",
215                          MCSectionMachO::S_ATTR_DEBUG,
216                          SectionKind::getMetadata());
217   DwarfMacroInfoSection =
218     Ctx->getMachOSection("__DWARF", "__debug_macinfo",
219                          MCSectionMachO::S_ATTR_DEBUG,
220                          SectionKind::getMetadata());
221   DwarfDebugInlineSection =
222     Ctx->getMachOSection("__DWARF", "__debug_inlined",
223                          MCSectionMachO::S_ATTR_DEBUG,
224                          SectionKind::getMetadata());
225 
226   TLSExtraDataSection = TLSTLVSection;
227 }
228 
229 void MCObjectFileInfo::InitELFMCObjectFileInfo(Triple T) {
230   if (T.getArch() == Triple::mips ||
231       T.getArch() == Triple::mipsel)
232     FDECFIEncoding = dwarf::DW_EH_PE_sdata4;
233   else if (T.getArch() == Triple::mips64 ||
234            T.getArch() == Triple::mips64el)
235     FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
236   else
237     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
238 
239   if (T.getArch() == Triple::x86) {
240     PersonalityEncoding = (RelocM == Reloc::PIC_)
241      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
242      : dwarf::DW_EH_PE_absptr;
243     LSDAEncoding = (RelocM == Reloc::PIC_)
244       ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
245       : dwarf::DW_EH_PE_absptr;
246     FDEEncoding = (RelocM == Reloc::PIC_)
247       ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
248       : dwarf::DW_EH_PE_absptr;
249     TTypeEncoding = (RelocM == Reloc::PIC_)
250      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
251      : dwarf::DW_EH_PE_absptr;
252   } else if (T.getArch() == Triple::x86_64) {
253     if (RelocM == Reloc::PIC_) {
254       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
255         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
256          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
257       LSDAEncoding = dwarf::DW_EH_PE_pcrel |
258         (CMModel == CodeModel::Small
259          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
260       FDEEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
261       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
262         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
263          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
264     } else {
265       PersonalityEncoding =
266         (CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
267         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
268       LSDAEncoding = (CMModel == CodeModel::Small)
269         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
270       FDEEncoding = dwarf::DW_EH_PE_udata4;
271       TTypeEncoding = (CMModel == CodeModel::Small)
272         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
273     }
274   }  else if (T.getArch() ==  Triple::aarch64) {
275     // The small model guarantees static code/data size < 4GB, but not where it
276     // will be in memory. Most of these could end up >2GB away so even a signed
277     // pc-relative 32-bit address is insufficient, theoretically.
278     if (RelocM == Reloc::PIC_) {
279       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
280         dwarf::DW_EH_PE_sdata8;
281       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
282       FDEEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
283       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
284         dwarf::DW_EH_PE_sdata8;
285     } else {
286       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
287       LSDAEncoding = dwarf::DW_EH_PE_absptr;
288       FDEEncoding = dwarf::DW_EH_PE_udata4;
289       TTypeEncoding = dwarf::DW_EH_PE_absptr;
290     }
291   } else if (T.getArch() == Triple::ppc64) {
292     PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
293       dwarf::DW_EH_PE_udata8;
294     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8;
295     FDEEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8;
296     TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
297       dwarf::DW_EH_PE_udata8;
298   }
299 
300   // Solaris requires different flags for .eh_frame to seemingly every other
301   // platform.
302   EHSectionType = ELF::SHT_PROGBITS;
303   EHSectionFlags = ELF::SHF_ALLOC;
304   if (T.getOS() == Triple::Solaris) {
305     if (T.getArch() == Triple::x86_64)
306       EHSectionType = ELF::SHT_X86_64_UNWIND;
307     else
308       EHSectionFlags |= ELF::SHF_WRITE;
309   }
310 
311 
312   // ELF
313   BSSSection =
314     Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
315                        ELF::SHF_WRITE | ELF::SHF_ALLOC,
316                        SectionKind::getBSS());
317 
318   TextSection =
319     Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
320                        ELF::SHF_EXECINSTR |
321                        ELF::SHF_ALLOC,
322                        SectionKind::getText());
323 
324   DataSection =
325     Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
326                        ELF::SHF_WRITE |ELF::SHF_ALLOC,
327                        SectionKind::getDataRel());
328 
329   ReadOnlySection =
330     Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS,
331                        ELF::SHF_ALLOC,
332                        SectionKind::getReadOnly());
333 
334   TLSDataSection =
335     Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
336                        ELF::SHF_ALLOC | ELF::SHF_TLS |
337                        ELF::SHF_WRITE,
338                        SectionKind::getThreadData());
339 
340   TLSBSSSection =
341     Ctx->getELFSection(".tbss", ELF::SHT_NOBITS,
342                        ELF::SHF_ALLOC | ELF::SHF_TLS |
343                        ELF::SHF_WRITE,
344                        SectionKind::getThreadBSS());
345 
346   DataRelSection =
347     Ctx->getELFSection(".data.rel", ELF::SHT_PROGBITS,
348                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
349                        SectionKind::getDataRel());
350 
351   DataRelLocalSection =
352     Ctx->getELFSection(".data.rel.local", ELF::SHT_PROGBITS,
353                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
354                        SectionKind::getDataRelLocal());
355 
356   DataRelROSection =
357     Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
358                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
359                        SectionKind::getReadOnlyWithRel());
360 
361   DataRelROLocalSection =
362     Ctx->getELFSection(".data.rel.ro.local", ELF::SHT_PROGBITS,
363                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
364                        SectionKind::getReadOnlyWithRelLocal());
365 
366   MergeableConst4Section =
367     Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
368                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
369                        SectionKind::getMergeableConst4());
370 
371   MergeableConst8Section =
372     Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
373                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
374                        SectionKind::getMergeableConst8());
375 
376   MergeableConst16Section =
377     Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
378                        ELF::SHF_ALLOC |ELF::SHF_MERGE,
379                        SectionKind::getMergeableConst16());
380 
381   StaticCtorSection =
382     Ctx->getELFSection(".ctors", ELF::SHT_PROGBITS,
383                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
384                        SectionKind::getDataRel());
385 
386   StaticDtorSection =
387     Ctx->getELFSection(".dtors", ELF::SHT_PROGBITS,
388                        ELF::SHF_ALLOC |ELF::SHF_WRITE,
389                        SectionKind::getDataRel());
390 
391   // Exception Handling Sections.
392 
393   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
394   // it contains relocatable pointers.  In PIC mode, this is probably a big
395   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
396   // adjusted or this should be a data section.
397   LSDASection =
398     Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
399                        ELF::SHF_ALLOC,
400                        SectionKind::getReadOnly());
401 
402   // Debug Info Sections.
403   DwarfAbbrevSection =
404     Ctx->getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0,
405                        SectionKind::getMetadata());
406   DwarfInfoSection =
407     Ctx->getELFSection(".debug_info", ELF::SHT_PROGBITS, 0,
408                        SectionKind::getMetadata());
409   DwarfLineSection =
410     Ctx->getELFSection(".debug_line", ELF::SHT_PROGBITS, 0,
411                        SectionKind::getMetadata());
412   DwarfFrameSection =
413     Ctx->getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0,
414                        SectionKind::getMetadata());
415   DwarfPubNamesSection =
416     Ctx->getELFSection(".debug_pubnames", ELF::SHT_PROGBITS, 0,
417                        SectionKind::getMetadata());
418   DwarfPubTypesSection =
419     Ctx->getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0,
420                        SectionKind::getMetadata());
421   DwarfStrSection =
422     Ctx->getELFSection(".debug_str", ELF::SHT_PROGBITS,
423                        ELF::SHF_MERGE | ELF::SHF_STRINGS,
424                        SectionKind::getMergeable1ByteCString());
425   DwarfLocSection =
426     Ctx->getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0,
427                        SectionKind::getMetadata());
428   DwarfARangesSection =
429     Ctx->getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0,
430                        SectionKind::getMetadata());
431   DwarfRangesSection =
432     Ctx->getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0,
433                        SectionKind::getMetadata());
434   DwarfMacroInfoSection =
435     Ctx->getELFSection(".debug_macinfo", ELF::SHT_PROGBITS, 0,
436                        SectionKind::getMetadata());
437 
438   // DWARF5 Experimental Debug Info
439 
440   // Accelerator Tables
441   DwarfAccelNamesSection =
442     Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0,
443                        SectionKind::getMetadata());
444   DwarfAccelObjCSection =
445     Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0,
446                        SectionKind::getMetadata());
447   DwarfAccelNamespaceSection =
448     Ctx->getELFSection(".apple_namespaces", ELF::SHT_PROGBITS, 0,
449                        SectionKind::getMetadata());
450   DwarfAccelTypesSection =
451     Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0,
452                        SectionKind::getMetadata());
453 
454   // Fission Sections
455   DwarfInfoDWOSection =
456     Ctx->getELFSection(".debug_info.dwo", ELF::SHT_PROGBITS, 0,
457                        SectionKind::getMetadata());
458   DwarfAbbrevDWOSection =
459     Ctx->getELFSection(".debug_abbrev.dwo", ELF::SHT_PROGBITS, 0,
460                        SectionKind::getMetadata());
461   DwarfStrDWOSection =
462     Ctx->getELFSection(".debug_str.dwo", ELF::SHT_PROGBITS,
463                        ELF::SHF_MERGE | ELF::SHF_STRINGS,
464                        SectionKind::getMergeable1ByteCString());
465   DwarfLineDWOSection =
466     Ctx->getELFSection(".debug_line.dwo", ELF::SHT_PROGBITS, 0,
467                        SectionKind::getMetadata());
468   DwarfLocDWOSection =
469     Ctx->getELFSection(".debug_loc.dwo", ELF::SHT_PROGBITS, 0,
470                        SectionKind::getMetadata());
471   DwarfStrOffDWOSection =
472     Ctx->getELFSection(".debug_str_offsets.dwo", ELF::SHT_PROGBITS, 0,
473                        SectionKind::getMetadata());
474   DwarfAddrSection =
475     Ctx->getELFSection(".debug_addr", ELF::SHT_PROGBITS, 0,
476                        SectionKind::getMetadata());
477 }
478 
479 
480 void MCObjectFileInfo::InitCOFFMCObjectFileInfo(Triple T) {
481   // COFF
482   TextSection =
483     Ctx->getCOFFSection(".text",
484                         COFF::IMAGE_SCN_CNT_CODE |
485                         COFF::IMAGE_SCN_MEM_EXECUTE |
486                         COFF::IMAGE_SCN_MEM_READ,
487                         SectionKind::getText());
488   DataSection =
489     Ctx->getCOFFSection(".data",
490                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
491                         COFF::IMAGE_SCN_MEM_READ |
492                         COFF::IMAGE_SCN_MEM_WRITE,
493                         SectionKind::getDataRel());
494   ReadOnlySection =
495     Ctx->getCOFFSection(".rdata",
496                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
497                         COFF::IMAGE_SCN_MEM_READ,
498                         SectionKind::getReadOnly());
499   if (T.getOS() == Triple::Win32) {
500     StaticCtorSection =
501       Ctx->getCOFFSection(".CRT$XCU",
502                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
503                           COFF::IMAGE_SCN_MEM_READ,
504                           SectionKind::getReadOnly());
505   } else {
506     StaticCtorSection =
507       Ctx->getCOFFSection(".ctors",
508                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
509                           COFF::IMAGE_SCN_MEM_READ |
510                           COFF::IMAGE_SCN_MEM_WRITE,
511                           SectionKind::getDataRel());
512   }
513 
514 
515   if (T.getOS() == Triple::Win32) {
516     StaticDtorSection =
517       Ctx->getCOFFSection(".CRT$XTX",
518                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
519                           COFF::IMAGE_SCN_MEM_READ,
520                           SectionKind::getReadOnly());
521   } else {
522     StaticDtorSection =
523       Ctx->getCOFFSection(".dtors",
524                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
525                           COFF::IMAGE_SCN_MEM_READ |
526                           COFF::IMAGE_SCN_MEM_WRITE,
527                           SectionKind::getDataRel());
528   }
529 
530   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
531   // though it contains relocatable pointers.  In PIC mode, this is probably a
532   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
533   // adjusted or this should be a data section.
534   LSDASection =
535     Ctx->getCOFFSection(".gcc_except_table",
536                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
537                         COFF::IMAGE_SCN_MEM_READ,
538                         SectionKind::getReadOnly());
539 
540   // Debug info.
541   DwarfAbbrevSection =
542     Ctx->getCOFFSection(".debug_abbrev",
543                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
544                         COFF::IMAGE_SCN_MEM_READ,
545                         SectionKind::getMetadata());
546   DwarfInfoSection =
547     Ctx->getCOFFSection(".debug_info",
548                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
549                         COFF::IMAGE_SCN_MEM_READ,
550                         SectionKind::getMetadata());
551   DwarfLineSection =
552     Ctx->getCOFFSection(".debug_line",
553                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
554                         COFF::IMAGE_SCN_MEM_READ,
555                         SectionKind::getMetadata());
556   DwarfFrameSection =
557     Ctx->getCOFFSection(".debug_frame",
558                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
559                         COFF::IMAGE_SCN_MEM_READ,
560                         SectionKind::getMetadata());
561   DwarfPubNamesSection =
562     Ctx->getCOFFSection(".debug_pubnames",
563                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
564                         COFF::IMAGE_SCN_MEM_READ,
565                         SectionKind::getMetadata());
566   DwarfPubTypesSection =
567     Ctx->getCOFFSection(".debug_pubtypes",
568                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
569                         COFF::IMAGE_SCN_MEM_READ,
570                         SectionKind::getMetadata());
571   DwarfStrSection =
572     Ctx->getCOFFSection(".debug_str",
573                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
574                         COFF::IMAGE_SCN_MEM_READ,
575                         SectionKind::getMetadata());
576   DwarfLocSection =
577     Ctx->getCOFFSection(".debug_loc",
578                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
579                         COFF::IMAGE_SCN_MEM_READ,
580                         SectionKind::getMetadata());
581   DwarfARangesSection =
582     Ctx->getCOFFSection(".debug_aranges",
583                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
584                         COFF::IMAGE_SCN_MEM_READ,
585                         SectionKind::getMetadata());
586   DwarfRangesSection =
587     Ctx->getCOFFSection(".debug_ranges",
588                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
589                         COFF::IMAGE_SCN_MEM_READ,
590                         SectionKind::getMetadata());
591   DwarfMacroInfoSection =
592     Ctx->getCOFFSection(".debug_macinfo",
593                         COFF::IMAGE_SCN_MEM_DISCARDABLE |
594                         COFF::IMAGE_SCN_MEM_READ,
595                         SectionKind::getMetadata());
596 
597   DrectveSection =
598     Ctx->getCOFFSection(".drectve",
599                         COFF::IMAGE_SCN_LNK_INFO,
600                         SectionKind::getMetadata());
601 
602   PDataSection =
603     Ctx->getCOFFSection(".pdata",
604                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
605                         COFF::IMAGE_SCN_MEM_READ,
606                         SectionKind::getDataRel());
607 
608   XDataSection =
609     Ctx->getCOFFSection(".xdata",
610                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
611                         COFF::IMAGE_SCN_MEM_READ,
612                         SectionKind::getDataRel());
613   TLSDataSection =
614     Ctx->getCOFFSection(".tls$",
615                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
616                         COFF::IMAGE_SCN_MEM_READ |
617                         COFF::IMAGE_SCN_MEM_WRITE,
618                         SectionKind::getDataRel());
619 }
620 
621 void MCObjectFileInfo::InitMCObjectFileInfo(StringRef TT, Reloc::Model relocm,
622                                             CodeModel::Model cm,
623                                             MCContext &ctx) {
624   RelocM = relocm;
625   CMModel = cm;
626   Ctx = &ctx;
627 
628   // Common.
629   CommDirectiveSupportsAlignment = true;
630   SupportsWeakOmittedEHFrame = true;
631   IsFunctionEHFrameSymbolPrivate = true;
632 
633   PersonalityEncoding = LSDAEncoding = FDEEncoding = FDECFIEncoding =
634     TTypeEncoding = dwarf::DW_EH_PE_absptr;
635 
636   CompactUnwindDwarfEHFrameOnly = 0;
637 
638   EHFrameSection = 0;             // Created on demand.
639   CompactUnwindSection = 0;       // Used only by selected targets.
640   DwarfAccelNamesSection = 0;     // Used only by selected targets.
641   DwarfAccelObjCSection = 0;      // Used only by selected targets.
642   DwarfAccelNamespaceSection = 0; // Used only by selected targets.
643   DwarfAccelTypesSection = 0;     // Used only by selected targets.
644 
645   Triple T(TT);
646   Triple::ArchType Arch = T.getArch();
647   // FIXME: Checking for Arch here to filter out bogus triples such as
648   // cellspu-apple-darwin. Perhaps we should fix in Triple?
649   if ((Arch == Triple::x86 || Arch == Triple::x86_64 ||
650        Arch == Triple::arm || Arch == Triple::thumb ||
651        Arch == Triple::ppc || Arch == Triple::ppc64 ||
652        Arch == Triple::UnknownArch) &&
653       (T.isOSDarwin() || T.getEnvironment() == Triple::MachO)) {
654     Env = IsMachO;
655     InitMachOMCObjectFileInfo(T);
656   } else if ((Arch == Triple::x86 || Arch == Triple::x86_64) &&
657              (T.getEnvironment() != Triple::ELF) &&
658              (T.getOS() == Triple::MinGW32 || T.getOS() == Triple::Cygwin ||
659               T.getOS() == Triple::Win32)) {
660     Env = IsCOFF;
661     InitCOFFMCObjectFileInfo(T);
662   } else {
663     Env = IsELF;
664     InitELFMCObjectFileInfo(T);
665   }
666 }
667 
668 void MCObjectFileInfo::InitEHFrameSection() {
669   if (Env == IsMachO)
670     EHFrameSection =
671       Ctx->getMachOSection("__TEXT", "__eh_frame",
672                            MCSectionMachO::S_COALESCED |
673                            MCSectionMachO::S_ATTR_NO_TOC |
674                            MCSectionMachO::S_ATTR_STRIP_STATIC_SYMS |
675                            MCSectionMachO::S_ATTR_LIVE_SUPPORT,
676                            SectionKind::getReadOnly());
677   else if (Env == IsELF)
678     EHFrameSection =
679       Ctx->getELFSection(".eh_frame", EHSectionType,
680                          EHSectionFlags,
681                          SectionKind::getDataRel());
682   else
683     EHFrameSection =
684       Ctx->getCOFFSection(".eh_frame",
685                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
686                           COFF::IMAGE_SCN_MEM_READ |
687                           COFF::IMAGE_SCN_MEM_WRITE,
688                           SectionKind::getDataRel());
689 }
690