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 #include "llvm/Support/COFF.h"
20 
21 using namespace llvm;
22 
useCompactUnwind(const Triple & T)23 static bool useCompactUnwind(const Triple &T) {
24   // Only on darwin.
25   if (!T.isOSDarwin())
26     return false;
27 
28   // aarch64 always has it.
29   if (T.getArch() == Triple::aarch64)
30     return true;
31 
32   // armv7k always has it.
33   if (T.isWatchOS())
34     return true;
35 
36   // Use it on newer version of OS X.
37   if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6))
38     return true;
39 
40   // And the iOS simulator.
41   if (T.isiOS() &&
42       (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86))
43     return true;
44 
45   return false;
46 }
47 
initMachOMCObjectFileInfo(Triple T)48 void MCObjectFileInfo::initMachOMCObjectFileInfo(Triple T) {
49   // MachO
50   SupportsWeakOmittedEHFrame = false;
51 
52   EHFrameSection = Ctx->getMachOSection(
53       "__TEXT", "__eh_frame",
54       MachO::S_COALESCED | MachO::S_ATTR_NO_TOC |
55           MachO::S_ATTR_STRIP_STATIC_SYMS | MachO::S_ATTR_LIVE_SUPPORT,
56       SectionKind::getReadOnly());
57 
58   if (T.isOSDarwin() && T.getArch() == Triple::aarch64)
59     SupportsCompactUnwindWithoutEHFrame = true;
60 
61   if (T.isWatchOS())
62     OmitDwarfIfHaveCompactUnwind = true;
63 
64   PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel
65     | dwarf::DW_EH_PE_sdata4;
66   LSDAEncoding = FDECFIEncoding = dwarf::DW_EH_PE_pcrel;
67   TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
68     dwarf::DW_EH_PE_sdata4;
69 
70   // .comm doesn't support alignment before Leopard.
71   if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
72     CommDirectiveSupportsAlignment = false;
73 
74   TextSection // .text
75     = Ctx->getMachOSection("__TEXT", "__text",
76                            MachO::S_ATTR_PURE_INSTRUCTIONS,
77                            SectionKind::getText());
78   DataSection // .data
79       = Ctx->getMachOSection("__DATA", "__data", 0, SectionKind::getData());
80 
81   // BSSSection might not be expected initialized on msvc.
82   BSSSection = nullptr;
83 
84   TLSDataSection // .tdata
85       = Ctx->getMachOSection("__DATA", "__thread_data",
86                              MachO::S_THREAD_LOCAL_REGULAR,
87                              SectionKind::getData());
88   TLSBSSSection // .tbss
89     = Ctx->getMachOSection("__DATA", "__thread_bss",
90                            MachO::S_THREAD_LOCAL_ZEROFILL,
91                            SectionKind::getThreadBSS());
92 
93   // TODO: Verify datarel below.
94   TLSTLVSection // .tlv
95       = Ctx->getMachOSection("__DATA", "__thread_vars",
96                              MachO::S_THREAD_LOCAL_VARIABLES,
97                              SectionKind::getData());
98 
99   TLSThreadInitSection = Ctx->getMachOSection(
100       "__DATA", "__thread_init", MachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
101       SectionKind::getData());
102 
103   CStringSection // .cstring
104     = Ctx->getMachOSection("__TEXT", "__cstring",
105                            MachO::S_CSTRING_LITERALS,
106                            SectionKind::getMergeable1ByteCString());
107   UStringSection
108     = Ctx->getMachOSection("__TEXT","__ustring", 0,
109                            SectionKind::getMergeable2ByteCString());
110   FourByteConstantSection // .literal4
111     = Ctx->getMachOSection("__TEXT", "__literal4",
112                            MachO::S_4BYTE_LITERALS,
113                            SectionKind::getMergeableConst4());
114   EightByteConstantSection // .literal8
115     = Ctx->getMachOSection("__TEXT", "__literal8",
116                            MachO::S_8BYTE_LITERALS,
117                            SectionKind::getMergeableConst8());
118 
119   SixteenByteConstantSection // .literal16
120       = Ctx->getMachOSection("__TEXT", "__literal16",
121                              MachO::S_16BYTE_LITERALS,
122                              SectionKind::getMergeableConst16());
123 
124   ReadOnlySection  // .const
125     = Ctx->getMachOSection("__TEXT", "__const", 0,
126                            SectionKind::getReadOnly());
127 
128   // If the target is not powerpc, map the coal sections to the non-coal
129   // sections.
130   //
131   // "__TEXT/__textcoal_nt" => section "__TEXT/__text"
132   // "__TEXT/__const_coal"  => section "__TEXT/__const"
133   // "__DATA/__datacoal_nt" => section "__DATA/__data"
134   Triple::ArchType ArchTy = T.getArch();
135 
136   if (ArchTy == Triple::ppc || ArchTy == Triple::ppc64) {
137     TextCoalSection
138       = Ctx->getMachOSection("__TEXT", "__textcoal_nt",
139                              MachO::S_COALESCED |
140                              MachO::S_ATTR_PURE_INSTRUCTIONS,
141                              SectionKind::getText());
142     ConstTextCoalSection
143       = Ctx->getMachOSection("__TEXT", "__const_coal",
144                              MachO::S_COALESCED,
145                              SectionKind::getReadOnly());
146     DataCoalSection = Ctx->getMachOSection(
147         "__DATA", "__datacoal_nt", MachO::S_COALESCED, SectionKind::getData());
148   } else {
149     TextCoalSection = TextSection;
150     ConstTextCoalSection = ReadOnlySection;
151     DataCoalSection = DataSection;
152   }
153 
154   ConstDataSection  // .const_data
155     = Ctx->getMachOSection("__DATA", "__const", 0,
156                            SectionKind::getReadOnlyWithRel());
157   DataCommonSection
158     = Ctx->getMachOSection("__DATA","__common",
159                            MachO::S_ZEROFILL,
160                            SectionKind::getBSS());
161   DataBSSSection
162     = Ctx->getMachOSection("__DATA","__bss", MachO::S_ZEROFILL,
163                            SectionKind::getBSS());
164 
165 
166   LazySymbolPointerSection
167     = Ctx->getMachOSection("__DATA", "__la_symbol_ptr",
168                            MachO::S_LAZY_SYMBOL_POINTERS,
169                            SectionKind::getMetadata());
170   NonLazySymbolPointerSection
171     = Ctx->getMachOSection("__DATA", "__nl_symbol_ptr",
172                            MachO::S_NON_LAZY_SYMBOL_POINTERS,
173                            SectionKind::getMetadata());
174 
175   if (RelocM == Reloc::Static) {
176     StaticCtorSection = Ctx->getMachOSection("__TEXT", "__constructor", 0,
177                                              SectionKind::getData());
178     StaticDtorSection = Ctx->getMachOSection("__TEXT", "__destructor", 0,
179                                              SectionKind::getData());
180   } else {
181     StaticCtorSection = Ctx->getMachOSection("__DATA", "__mod_init_func",
182                                              MachO::S_MOD_INIT_FUNC_POINTERS,
183                                              SectionKind::getData());
184     StaticDtorSection = Ctx->getMachOSection("__DATA", "__mod_term_func",
185                                              MachO::S_MOD_TERM_FUNC_POINTERS,
186                                              SectionKind::getData());
187   }
188 
189   // Exception Handling.
190   LSDASection = Ctx->getMachOSection("__TEXT", "__gcc_except_tab", 0,
191                                      SectionKind::getReadOnlyWithRel());
192 
193   COFFDebugSymbolsSection = nullptr;
194 
195   if (useCompactUnwind(T)) {
196     CompactUnwindSection =
197         Ctx->getMachOSection("__LD", "__compact_unwind", MachO::S_ATTR_DEBUG,
198                              SectionKind::getReadOnly());
199 
200     if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86)
201       CompactUnwindDwarfEHFrameOnly = 0x04000000;  // UNWIND_X86_64_MODE_DWARF
202     else if (T.getArch() == Triple::aarch64)
203       CompactUnwindDwarfEHFrameOnly = 0x03000000;  // UNWIND_ARM64_MODE_DWARF
204     else if (T.getArch() == Triple::arm || T.getArch() == Triple::thumb)
205       CompactUnwindDwarfEHFrameOnly = 0x04000000;  // UNWIND_ARM_MODE_DWARF
206   }
207 
208   // Debug Information.
209   DwarfAccelNamesSection =
210       Ctx->getMachOSection("__DWARF", "__apple_names", MachO::S_ATTR_DEBUG,
211                            SectionKind::getMetadata(), "names_begin");
212   DwarfAccelObjCSection =
213       Ctx->getMachOSection("__DWARF", "__apple_objc", MachO::S_ATTR_DEBUG,
214                            SectionKind::getMetadata(), "objc_begin");
215   // 16 character section limit...
216   DwarfAccelNamespaceSection =
217       Ctx->getMachOSection("__DWARF", "__apple_namespac", MachO::S_ATTR_DEBUG,
218                            SectionKind::getMetadata(), "namespac_begin");
219   DwarfAccelTypesSection =
220       Ctx->getMachOSection("__DWARF", "__apple_types", MachO::S_ATTR_DEBUG,
221                            SectionKind::getMetadata(), "types_begin");
222 
223   DwarfAbbrevSection =
224       Ctx->getMachOSection("__DWARF", "__debug_abbrev", MachO::S_ATTR_DEBUG,
225                            SectionKind::getMetadata(), "section_abbrev");
226   DwarfInfoSection =
227       Ctx->getMachOSection("__DWARF", "__debug_info", MachO::S_ATTR_DEBUG,
228                            SectionKind::getMetadata(), "section_info");
229   DwarfLineSection =
230       Ctx->getMachOSection("__DWARF", "__debug_line", MachO::S_ATTR_DEBUG,
231                            SectionKind::getMetadata(), "section_line");
232   DwarfFrameSection =
233       Ctx->getMachOSection("__DWARF", "__debug_frame", MachO::S_ATTR_DEBUG,
234                            SectionKind::getMetadata());
235   DwarfPubNamesSection =
236       Ctx->getMachOSection("__DWARF", "__debug_pubnames", MachO::S_ATTR_DEBUG,
237                            SectionKind::getMetadata());
238   DwarfPubTypesSection =
239       Ctx->getMachOSection("__DWARF", "__debug_pubtypes", MachO::S_ATTR_DEBUG,
240                            SectionKind::getMetadata());
241   DwarfGnuPubNamesSection =
242       Ctx->getMachOSection("__DWARF", "__debug_gnu_pubn", MachO::S_ATTR_DEBUG,
243                            SectionKind::getMetadata());
244   DwarfGnuPubTypesSection =
245       Ctx->getMachOSection("__DWARF", "__debug_gnu_pubt", MachO::S_ATTR_DEBUG,
246                            SectionKind::getMetadata());
247   DwarfStrSection =
248       Ctx->getMachOSection("__DWARF", "__debug_str", MachO::S_ATTR_DEBUG,
249                            SectionKind::getMetadata(), "info_string");
250   DwarfLocSection =
251       Ctx->getMachOSection("__DWARF", "__debug_loc", MachO::S_ATTR_DEBUG,
252                            SectionKind::getMetadata(), "section_debug_loc");
253   DwarfARangesSection =
254       Ctx->getMachOSection("__DWARF", "__debug_aranges", MachO::S_ATTR_DEBUG,
255                            SectionKind::getMetadata());
256   DwarfRangesSection =
257       Ctx->getMachOSection("__DWARF", "__debug_ranges", MachO::S_ATTR_DEBUG,
258                            SectionKind::getMetadata(), "debug_range");
259   DwarfDebugInlineSection =
260       Ctx->getMachOSection("__DWARF", "__debug_inlined", MachO::S_ATTR_DEBUG,
261                            SectionKind::getMetadata());
262   DwarfCUIndexSection =
263       Ctx->getMachOSection("__DWARF", "__debug_cu_index", MachO::S_ATTR_DEBUG,
264                            SectionKind::getMetadata());
265   DwarfTUIndexSection =
266       Ctx->getMachOSection("__DWARF", "__debug_tu_index", MachO::S_ATTR_DEBUG,
267                            SectionKind::getMetadata());
268   StackMapSection = Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps",
269                                          0, SectionKind::getMetadata());
270 
271   FaultMapSection = Ctx->getMachOSection("__LLVM_FAULTMAPS", "__llvm_faultmaps",
272                                          0, SectionKind::getMetadata());
273 
274   TLSExtraDataSection = TLSTLVSection;
275 }
276 
initELFMCObjectFileInfo(Triple T)277 void MCObjectFileInfo::initELFMCObjectFileInfo(Triple T) {
278   switch (T.getArch()) {
279   case Triple::mips:
280   case Triple::mipsel:
281     FDECFIEncoding = dwarf::DW_EH_PE_sdata4;
282     break;
283   case Triple::mips64:
284   case Triple::mips64el:
285     FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
286     break;
287   case Triple::x86_64:
288     FDECFIEncoding = dwarf::DW_EH_PE_pcrel |
289                      ((CMModel == CodeModel::Large) ? dwarf::DW_EH_PE_sdata8
290                                                     : dwarf::DW_EH_PE_sdata4);
291     break;
292   default:
293     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
294     break;
295   }
296 
297   switch (T.getArch()) {
298   case Triple::arm:
299   case Triple::armeb:
300   case Triple::thumb:
301   case Triple::thumbeb:
302     if (Ctx->getAsmInfo()->getExceptionHandlingType() == ExceptionHandling::ARM)
303       break;
304     // Fallthrough if not using EHABI
305   case Triple::ppc:
306   case Triple::x86:
307     PersonalityEncoding = (RelocM == Reloc::PIC_)
308      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
309      : dwarf::DW_EH_PE_absptr;
310     LSDAEncoding = (RelocM == Reloc::PIC_)
311       ? dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
312       : dwarf::DW_EH_PE_absptr;
313     TTypeEncoding = (RelocM == Reloc::PIC_)
314      ? dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4
315      : dwarf::DW_EH_PE_absptr;
316     break;
317   case Triple::x86_64:
318     if (RelocM == Reloc::PIC_) {
319       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
320         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
321          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
322       LSDAEncoding = dwarf::DW_EH_PE_pcrel |
323         (CMModel == CodeModel::Small
324          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
325       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
326         ((CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
327          ? dwarf::DW_EH_PE_sdata4 : dwarf::DW_EH_PE_sdata8);
328     } else {
329       PersonalityEncoding =
330         (CMModel == CodeModel::Small || CMModel == CodeModel::Medium)
331         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
332       LSDAEncoding = (CMModel == CodeModel::Small)
333         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
334       TTypeEncoding = (CMModel == CodeModel::Small)
335         ? dwarf::DW_EH_PE_udata4 : dwarf::DW_EH_PE_absptr;
336     }
337     break;
338   case Triple::aarch64:
339   case Triple::aarch64_be:
340     // The small model guarantees static code/data size < 4GB, but not where it
341     // will be in memory. Most of these could end up >2GB away so even a signed
342     // pc-relative 32-bit address is insufficient, theoretically.
343     if (RelocM == Reloc::PIC_) {
344       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
345         dwarf::DW_EH_PE_sdata8;
346       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata8;
347       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
348         dwarf::DW_EH_PE_sdata8;
349     } else {
350       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
351       LSDAEncoding = dwarf::DW_EH_PE_absptr;
352       TTypeEncoding = dwarf::DW_EH_PE_absptr;
353     }
354     break;
355   case Triple::mips:
356   case Triple::mipsel:
357   case Triple::mips64:
358   case Triple::mips64el:
359     // MIPS uses indirect pointer to refer personality functions and types, so
360     // that the eh_frame section can be read-only. DW.ref.personality will be
361     // generated for relocation.
362     PersonalityEncoding = dwarf::DW_EH_PE_indirect;
363     // FIXME: The N64 ABI probably ought to use DW_EH_PE_sdata8 but we can't
364     //        identify N64 from just a triple.
365     TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
366                     dwarf::DW_EH_PE_sdata4;
367     // We don't support PC-relative LSDA references in GAS so we use the default
368     // DW_EH_PE_absptr for those.
369     break;
370   case Triple::ppc64:
371   case Triple::ppc64le:
372     PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
373       dwarf::DW_EH_PE_udata8;
374     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_udata8;
375     TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
376       dwarf::DW_EH_PE_udata8;
377     break;
378   case Triple::sparcel:
379   case Triple::sparc:
380     if (RelocM == Reloc::PIC_) {
381       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
382       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
383         dwarf::DW_EH_PE_sdata4;
384       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
385         dwarf::DW_EH_PE_sdata4;
386     } else {
387       LSDAEncoding = dwarf::DW_EH_PE_absptr;
388       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
389       TTypeEncoding = dwarf::DW_EH_PE_absptr;
390     }
391     break;
392   case Triple::sparcv9:
393     LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
394     if (RelocM == Reloc::PIC_) {
395       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
396         dwarf::DW_EH_PE_sdata4;
397       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
398         dwarf::DW_EH_PE_sdata4;
399     } else {
400       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
401       TTypeEncoding = dwarf::DW_EH_PE_absptr;
402     }
403     break;
404   case Triple::systemz:
405     // All currently-defined code models guarantee that 4-byte PC-relative
406     // values will be in range.
407     if (RelocM == Reloc::PIC_) {
408       PersonalityEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
409         dwarf::DW_EH_PE_sdata4;
410       LSDAEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
411       TTypeEncoding = dwarf::DW_EH_PE_indirect | dwarf::DW_EH_PE_pcrel |
412         dwarf::DW_EH_PE_sdata4;
413     } else {
414       PersonalityEncoding = dwarf::DW_EH_PE_absptr;
415       LSDAEncoding = dwarf::DW_EH_PE_absptr;
416       TTypeEncoding = dwarf::DW_EH_PE_absptr;
417     }
418     break;
419   default:
420     break;
421   }
422 
423   unsigned EHSectionType = T.getArch() == Triple::x86_64
424                                ? ELF::SHT_X86_64_UNWIND
425                                : ELF::SHT_PROGBITS;
426 
427   // Solaris requires different flags for .eh_frame to seemingly every other
428   // platform.
429   unsigned EHSectionFlags = ELF::SHF_ALLOC;
430   if (T.isOSSolaris() && T.getArch() != Triple::x86_64)
431     EHSectionFlags |= ELF::SHF_WRITE;
432 
433   // ELF
434   BSSSection = Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
435                                   ELF::SHF_WRITE | ELF::SHF_ALLOC);
436 
437   TextSection = Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
438                                    ELF::SHF_EXECINSTR | ELF::SHF_ALLOC);
439 
440   DataSection = Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
441                                    ELF::SHF_WRITE | ELF::SHF_ALLOC);
442 
443   ReadOnlySection =
444       Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
445 
446   TLSDataSection =
447       Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
448                          ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
449 
450   TLSBSSSection = Ctx->getELFSection(
451       ".tbss", ELF::SHT_NOBITS, ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
452 
453   DataRelROSection = Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
454                                         ELF::SHF_ALLOC | ELF::SHF_WRITE);
455 
456   MergeableConst4Section =
457       Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
458                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 4, "");
459 
460   MergeableConst8Section =
461       Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
462                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 8, "");
463 
464   MergeableConst16Section =
465       Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
466                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 16, "");
467 
468   StaticCtorSection = Ctx->getELFSection(".ctors", ELF::SHT_PROGBITS,
469                                          ELF::SHF_ALLOC | ELF::SHF_WRITE);
470 
471   StaticDtorSection = Ctx->getELFSection(".dtors", ELF::SHT_PROGBITS,
472                                          ELF::SHF_ALLOC | ELF::SHF_WRITE);
473 
474   // Exception Handling Sections.
475 
476   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
477   // it contains relocatable pointers.  In PIC mode, this is probably a big
478   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
479   // adjusted or this should be a data section.
480   LSDASection = Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
481                                    ELF::SHF_ALLOC);
482 
483   COFFDebugSymbolsSection = nullptr;
484 
485   // Debug Info Sections.
486   DwarfAbbrevSection = Ctx->getELFSection(".debug_abbrev", ELF::SHT_PROGBITS, 0,
487                                           "section_abbrev");
488   DwarfInfoSection =
489       Ctx->getELFSection(".debug_info", ELF::SHT_PROGBITS, 0, "section_info");
490   DwarfLineSection = Ctx->getELFSection(".debug_line", ELF::SHT_PROGBITS, 0);
491   DwarfFrameSection = Ctx->getELFSection(".debug_frame", ELF::SHT_PROGBITS, 0);
492   DwarfPubNamesSection =
493       Ctx->getELFSection(".debug_pubnames", ELF::SHT_PROGBITS, 0);
494   DwarfPubTypesSection =
495       Ctx->getELFSection(".debug_pubtypes", ELF::SHT_PROGBITS, 0);
496   DwarfGnuPubNamesSection =
497       Ctx->getELFSection(".debug_gnu_pubnames", ELF::SHT_PROGBITS, 0);
498   DwarfGnuPubTypesSection =
499       Ctx->getELFSection(".debug_gnu_pubtypes", ELF::SHT_PROGBITS, 0);
500   DwarfStrSection =
501       Ctx->getELFSection(".debug_str", ELF::SHT_PROGBITS,
502                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
503   DwarfLocSection = Ctx->getELFSection(".debug_loc", ELF::SHT_PROGBITS, 0);
504   DwarfARangesSection =
505       Ctx->getELFSection(".debug_aranges", ELF::SHT_PROGBITS, 0);
506   DwarfRangesSection =
507       Ctx->getELFSection(".debug_ranges", ELF::SHT_PROGBITS, 0, "debug_range");
508 
509   // DWARF5 Experimental Debug Info
510 
511   // Accelerator Tables
512   DwarfAccelNamesSection =
513       Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0, "names_begin");
514   DwarfAccelObjCSection =
515       Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0, "objc_begin");
516   DwarfAccelNamespaceSection = Ctx->getELFSection(
517       ".apple_namespaces", ELF::SHT_PROGBITS, 0, "namespac_begin");
518   DwarfAccelTypesSection =
519       Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0, "types_begin");
520 
521   // Fission Sections
522   DwarfInfoDWOSection =
523       Ctx->getELFSection(".debug_info.dwo", ELF::SHT_PROGBITS, 0);
524   DwarfTypesDWOSection =
525       Ctx->getELFSection(".debug_types.dwo", ELF::SHT_PROGBITS, 0);
526   DwarfAbbrevDWOSection =
527       Ctx->getELFSection(".debug_abbrev.dwo", ELF::SHT_PROGBITS, 0);
528   DwarfStrDWOSection =
529       Ctx->getELFSection(".debug_str.dwo", ELF::SHT_PROGBITS,
530                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
531   DwarfLineDWOSection =
532       Ctx->getELFSection(".debug_line.dwo", ELF::SHT_PROGBITS, 0);
533   DwarfLocDWOSection =
534       Ctx->getELFSection(".debug_loc.dwo", ELF::SHT_PROGBITS, 0, "skel_loc");
535   DwarfStrOffDWOSection =
536       Ctx->getELFSection(".debug_str_offsets.dwo", ELF::SHT_PROGBITS, 0);
537   DwarfAddrSection =
538       Ctx->getELFSection(".debug_addr", ELF::SHT_PROGBITS, 0, "addr_sec");
539 
540   // DWP Sections
541   DwarfCUIndexSection =
542       Ctx->getELFSection(".debug_cu_index", ELF::SHT_PROGBITS, 0);
543   DwarfTUIndexSection =
544       Ctx->getELFSection(".debug_tu_index", ELF::SHT_PROGBITS, 0);
545 
546   StackMapSection =
547       Ctx->getELFSection(".llvm_stackmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
548 
549   FaultMapSection =
550       Ctx->getELFSection(".llvm_faultmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
551 
552   EHFrameSection =
553       Ctx->getELFSection(".eh_frame", EHSectionType, EHSectionFlags);
554 }
555 
initCOFFMCObjectFileInfo(Triple T)556 void MCObjectFileInfo::initCOFFMCObjectFileInfo(Triple T) {
557   EHFrameSection = Ctx->getCOFFSection(
558       ".eh_frame", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
559                        COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
560       SectionKind::getData());
561 
562   bool IsWoA = T.getArch() == Triple::arm || T.getArch() == Triple::thumb;
563 
564   CommDirectiveSupportsAlignment = true;
565 
566   // COFF
567   BSSSection = Ctx->getCOFFSection(
568       ".bss", COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
569                   COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
570       SectionKind::getBSS());
571   TextSection = Ctx->getCOFFSection(
572       ".text",
573       (IsWoA ? COFF::IMAGE_SCN_MEM_16BIT : (COFF::SectionCharacteristics)0) |
574           COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE |
575           COFF::IMAGE_SCN_MEM_READ,
576       SectionKind::getText());
577   DataSection = Ctx->getCOFFSection(
578       ".data", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
579                    COFF::IMAGE_SCN_MEM_WRITE,
580       SectionKind::getData());
581   ReadOnlySection = Ctx->getCOFFSection(
582       ".rdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
583       SectionKind::getReadOnly());
584 
585   if (T.isKnownWindowsMSVCEnvironment() || T.isWindowsItaniumEnvironment()) {
586     StaticCtorSection =
587         Ctx->getCOFFSection(".CRT$XCU", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
588                                             COFF::IMAGE_SCN_MEM_READ,
589                             SectionKind::getReadOnly());
590     StaticDtorSection =
591         Ctx->getCOFFSection(".CRT$XTX", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
592                                             COFF::IMAGE_SCN_MEM_READ,
593                             SectionKind::getReadOnly());
594   } else {
595     StaticCtorSection = Ctx->getCOFFSection(
596         ".ctors", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
597                       COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
598         SectionKind::getData());
599     StaticDtorSection = Ctx->getCOFFSection(
600         ".dtors", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
601                       COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
602         SectionKind::getData());
603   }
604 
605   // FIXME: We're emitting LSDA info into a readonly section on COFF, even
606   // though it contains relocatable pointers.  In PIC mode, this is probably a
607   // big runtime hit for C++ apps.  Either the contents of the LSDA need to be
608   // adjusted or this should be a data section.
609   if (T.getArch() == Triple::x86_64) {
610     // On Windows 64 with SEH, the LSDA is emitted into the .xdata section
611     LSDASection = nullptr;
612   } else {
613     LSDASection = Ctx->getCOFFSection(".gcc_except_table",
614                                       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
615                                           COFF::IMAGE_SCN_MEM_READ,
616                                       SectionKind::getReadOnly());
617   }
618 
619   // Debug info.
620   COFFDebugSymbolsSection =
621       Ctx->getCOFFSection(".debug$S", COFF::IMAGE_SCN_MEM_DISCARDABLE |
622                                           COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
623                                           COFF::IMAGE_SCN_MEM_READ,
624                           SectionKind::getMetadata());
625 
626   DwarfAbbrevSection = Ctx->getCOFFSection(
627       ".debug_abbrev",
628       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
629           COFF::IMAGE_SCN_MEM_READ,
630       SectionKind::getMetadata(), "section_abbrev");
631   DwarfInfoSection = Ctx->getCOFFSection(
632       ".debug_info",
633       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
634           COFF::IMAGE_SCN_MEM_READ,
635       SectionKind::getMetadata(), "section_info");
636   DwarfLineSection = Ctx->getCOFFSection(
637       ".debug_line",
638       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
639           COFF::IMAGE_SCN_MEM_READ,
640       SectionKind::getMetadata(), "section_line");
641 
642   DwarfFrameSection = Ctx->getCOFFSection(
643       ".debug_frame",
644       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
645           COFF::IMAGE_SCN_MEM_READ,
646       SectionKind::getMetadata());
647   DwarfPubNamesSection = Ctx->getCOFFSection(
648       ".debug_pubnames",
649       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
650           COFF::IMAGE_SCN_MEM_READ,
651       SectionKind::getMetadata());
652   DwarfPubTypesSection = Ctx->getCOFFSection(
653       ".debug_pubtypes",
654       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
655           COFF::IMAGE_SCN_MEM_READ,
656       SectionKind::getMetadata());
657   DwarfGnuPubNamesSection = Ctx->getCOFFSection(
658       ".debug_gnu_pubnames",
659       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
660           COFF::IMAGE_SCN_MEM_READ,
661       SectionKind::getMetadata());
662   DwarfGnuPubTypesSection = Ctx->getCOFFSection(
663       ".debug_gnu_pubtypes",
664       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
665           COFF::IMAGE_SCN_MEM_READ,
666       SectionKind::getMetadata());
667   DwarfStrSection = Ctx->getCOFFSection(
668       ".debug_str",
669       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
670           COFF::IMAGE_SCN_MEM_READ,
671       SectionKind::getMetadata(), "info_string");
672   DwarfLocSection = Ctx->getCOFFSection(
673       ".debug_loc",
674       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
675           COFF::IMAGE_SCN_MEM_READ,
676       SectionKind::getMetadata(), "section_debug_loc");
677   DwarfARangesSection = Ctx->getCOFFSection(
678       ".debug_aranges",
679       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
680           COFF::IMAGE_SCN_MEM_READ,
681       SectionKind::getMetadata());
682   DwarfRangesSection = Ctx->getCOFFSection(
683       ".debug_ranges",
684       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
685           COFF::IMAGE_SCN_MEM_READ,
686       SectionKind::getMetadata(), "debug_range");
687   DwarfInfoDWOSection = Ctx->getCOFFSection(
688       ".debug_info.dwo",
689       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
690           COFF::IMAGE_SCN_MEM_READ,
691       SectionKind::getMetadata(), "section_info_dwo");
692   DwarfTypesDWOSection = Ctx->getCOFFSection(
693       ".debug_types.dwo",
694       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
695           COFF::IMAGE_SCN_MEM_READ,
696       SectionKind::getMetadata(), "section_types_dwo");
697   DwarfAbbrevDWOSection = Ctx->getCOFFSection(
698       ".debug_abbrev.dwo",
699       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
700           COFF::IMAGE_SCN_MEM_READ,
701       SectionKind::getMetadata(), "section_abbrev_dwo");
702   DwarfStrDWOSection = Ctx->getCOFFSection(
703       ".debug_str.dwo",
704       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
705           COFF::IMAGE_SCN_MEM_READ,
706       SectionKind::getMetadata(), "skel_string");
707   DwarfLineDWOSection = Ctx->getCOFFSection(
708       ".debug_line.dwo",
709       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
710           COFF::IMAGE_SCN_MEM_READ,
711       SectionKind::getMetadata());
712   DwarfLocDWOSection = Ctx->getCOFFSection(
713       ".debug_loc.dwo",
714       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
715           COFF::IMAGE_SCN_MEM_READ,
716       SectionKind::getMetadata(), "skel_loc");
717   DwarfStrOffDWOSection = Ctx->getCOFFSection(
718       ".debug_str_offsets.dwo",
719       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
720           COFF::IMAGE_SCN_MEM_READ,
721       SectionKind::getMetadata());
722   DwarfAddrSection = Ctx->getCOFFSection(
723       ".debug_addr",
724       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
725           COFF::IMAGE_SCN_MEM_READ,
726       SectionKind::getMetadata(), "addr_sec");
727   DwarfCUIndexSection = Ctx->getCOFFSection(
728       ".debug_cu_index",
729       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
730           COFF::IMAGE_SCN_MEM_READ,
731       SectionKind::getMetadata());
732   DwarfTUIndexSection = Ctx->getCOFFSection(
733       ".debug_tu_index",
734       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
735           COFF::IMAGE_SCN_MEM_READ,
736       SectionKind::getMetadata());
737   DwarfAccelNamesSection = Ctx->getCOFFSection(
738       ".apple_names",
739       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
740           COFF::IMAGE_SCN_MEM_READ,
741       SectionKind::getMetadata(), "names_begin");
742   DwarfAccelNamespaceSection = Ctx->getCOFFSection(
743       ".apple_namespaces",
744       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
745           COFF::IMAGE_SCN_MEM_READ,
746       SectionKind::getMetadata(), "namespac_begin");
747   DwarfAccelTypesSection = Ctx->getCOFFSection(
748       ".apple_types",
749       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
750           COFF::IMAGE_SCN_MEM_READ,
751       SectionKind::getMetadata(), "types_begin");
752   DwarfAccelObjCSection = Ctx->getCOFFSection(
753       ".apple_objc",
754       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
755           COFF::IMAGE_SCN_MEM_READ,
756       SectionKind::getMetadata(), "objc_begin");
757 
758   DrectveSection = Ctx->getCOFFSection(
759       ".drectve", COFF::IMAGE_SCN_LNK_INFO | COFF::IMAGE_SCN_LNK_REMOVE,
760       SectionKind::getMetadata());
761 
762   PDataSection = Ctx->getCOFFSection(
763       ".pdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
764       SectionKind::getData());
765 
766   XDataSection = Ctx->getCOFFSection(
767       ".xdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
768       SectionKind::getData());
769 
770   SXDataSection = Ctx->getCOFFSection(".sxdata", COFF::IMAGE_SCN_LNK_INFO,
771                                       SectionKind::getMetadata());
772 
773   TLSDataSection = Ctx->getCOFFSection(
774       ".tls$", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
775                    COFF::IMAGE_SCN_MEM_WRITE,
776       SectionKind::getData());
777 
778   StackMapSection = Ctx->getCOFFSection(".llvm_stackmaps",
779                                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
780                                             COFF::IMAGE_SCN_MEM_READ,
781                                         SectionKind::getReadOnly());
782 }
783 
InitMCObjectFileInfo(const Triple & TheTriple,Reloc::Model relocm,CodeModel::Model cm,MCContext & ctx)784 void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple,
785                                             Reloc::Model relocm,
786                                             CodeModel::Model cm,
787                                             MCContext &ctx) {
788   RelocM = relocm;
789   CMModel = cm;
790   Ctx = &ctx;
791 
792   // Common.
793   CommDirectiveSupportsAlignment = true;
794   SupportsWeakOmittedEHFrame = true;
795   SupportsCompactUnwindWithoutEHFrame = false;
796   OmitDwarfIfHaveCompactUnwind = false;
797 
798   PersonalityEncoding = LSDAEncoding = FDECFIEncoding = TTypeEncoding =
799       dwarf::DW_EH_PE_absptr;
800 
801   CompactUnwindDwarfEHFrameOnly = 0;
802 
803   EHFrameSection = nullptr;             // Created on demand.
804   CompactUnwindSection = nullptr;       // Used only by selected targets.
805   DwarfAccelNamesSection = nullptr;     // Used only by selected targets.
806   DwarfAccelObjCSection = nullptr;      // Used only by selected targets.
807   DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
808   DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
809 
810   TT = TheTriple;
811 
812   switch (TT.getObjectFormat()) {
813   case Triple::MachO:
814     Env = IsMachO;
815     initMachOMCObjectFileInfo(TT);
816     break;
817   case Triple::COFF:
818     if (!TT.isOSWindows())
819       report_fatal_error(
820           "Cannot initialize MC for non-Windows COFF object files.");
821 
822     Env = IsCOFF;
823     initCOFFMCObjectFileInfo(TT);
824     break;
825   case Triple::ELF:
826     Env = IsELF;
827     initELFMCObjectFileInfo(TT);
828     break;
829   case Triple::UnknownObjectFormat:
830     report_fatal_error("Cannot initialize MC for unknown object file format.");
831     break;
832   }
833 }
834 
InitMCObjectFileInfo(StringRef TT,Reloc::Model RM,CodeModel::Model CM,MCContext & ctx)835 void MCObjectFileInfo::InitMCObjectFileInfo(StringRef TT, Reloc::Model RM,
836                                             CodeModel::Model CM,
837                                             MCContext &ctx) {
838   InitMCObjectFileInfo(Triple(TT), RM, CM, ctx);
839 }
840 
getDwarfTypesSection(uint64_t Hash) const841 MCSection *MCObjectFileInfo::getDwarfTypesSection(uint64_t Hash) const {
842   return Ctx->getELFSection(".debug_types", ELF::SHT_PROGBITS, ELF::SHF_GROUP,
843                             0, utostr(Hash));
844 }
845