1 //===-- MCObjectFileInfo.cpp - Object File Information --------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 
9 #include "llvm/MC/MCObjectFileInfo.h"
10 #include "llvm/ADT/StringExtras.h"
11 #include "llvm/ADT/Triple.h"
12 #include "llvm/BinaryFormat/COFF.h"
13 #include "llvm/BinaryFormat/ELF.h"
14 #include "llvm/MC/MCAsmInfo.h"
15 #include "llvm/MC/MCContext.h"
16 #include "llvm/MC/MCSection.h"
17 #include "llvm/MC/MCSectionCOFF.h"
18 #include "llvm/MC/MCSectionELF.h"
19 #include "llvm/MC/MCSectionMachO.h"
20 #include "llvm/MC/MCSectionWasm.h"
21 #include "llvm/MC/MCSectionXCOFF.h"
22 
23 using namespace llvm;
24 
useCompactUnwind(const Triple & T)25 static bool useCompactUnwind(const Triple &T) {
26   // Only on darwin.
27   if (!T.isOSDarwin())
28     return false;
29 
30   // aarch64 always has it.
31   if (T.getArch() == Triple::aarch64)
32     return true;
33 
34   // armv7k always has it.
35   if (T.isWatchABI())
36     return true;
37 
38   // Use it on newer version of OS X.
39   if (T.isMacOSX() && !T.isMacOSXVersionLT(10, 6))
40     return true;
41 
42   // And the iOS simulator.
43   if (T.isiOS() &&
44       (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86))
45     return true;
46 
47   return false;
48 }
49 
initMachOMCObjectFileInfo(const Triple & T)50 void MCObjectFileInfo::initMachOMCObjectFileInfo(const Triple &T) {
51   // MachO
52   SupportsWeakOmittedEHFrame = false;
53 
54   EHFrameSection = Ctx->getMachOSection(
55       "__TEXT", "__eh_frame",
56       MachO::S_COALESCED | MachO::S_ATTR_NO_TOC |
57           MachO::S_ATTR_STRIP_STATIC_SYMS | MachO::S_ATTR_LIVE_SUPPORT,
58       SectionKind::getReadOnly());
59 
60   if (T.isOSDarwin() && T.getArch() == Triple::aarch64)
61     SupportsCompactUnwindWithoutEHFrame = true;
62 
63   if (T.isWatchABI())
64     OmitDwarfIfHaveCompactUnwind = true;
65 
66   FDECFIEncoding = dwarf::DW_EH_PE_pcrel;
67 
68   // .comm doesn't support alignment before Leopard.
69   if (T.isMacOSX() && T.isMacOSXVersionLT(10, 5))
70     CommDirectiveSupportsAlignment = false;
71 
72   TextSection // .text
73     = Ctx->getMachOSection("__TEXT", "__text",
74                            MachO::S_ATTR_PURE_INSTRUCTIONS,
75                            SectionKind::getText());
76   DataSection // .data
77       = Ctx->getMachOSection("__DATA", "__data", 0, SectionKind::getData());
78 
79   // BSSSection might not be expected initialized on msvc.
80   BSSSection = nullptr;
81 
82   TLSDataSection // .tdata
83       = Ctx->getMachOSection("__DATA", "__thread_data",
84                              MachO::S_THREAD_LOCAL_REGULAR,
85                              SectionKind::getData());
86   TLSBSSSection // .tbss
87     = Ctx->getMachOSection("__DATA", "__thread_bss",
88                            MachO::S_THREAD_LOCAL_ZEROFILL,
89                            SectionKind::getThreadBSS());
90 
91   // TODO: Verify datarel below.
92   TLSTLVSection // .tlv
93       = Ctx->getMachOSection("__DATA", "__thread_vars",
94                              MachO::S_THREAD_LOCAL_VARIABLES,
95                              SectionKind::getData());
96 
97   TLSThreadInitSection = Ctx->getMachOSection(
98       "__DATA", "__thread_init", MachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS,
99       SectionKind::getData());
100 
101   CStringSection // .cstring
102     = Ctx->getMachOSection("__TEXT", "__cstring",
103                            MachO::S_CSTRING_LITERALS,
104                            SectionKind::getMergeable1ByteCString());
105   UStringSection
106     = Ctx->getMachOSection("__TEXT","__ustring", 0,
107                            SectionKind::getMergeable2ByteCString());
108   FourByteConstantSection // .literal4
109     = Ctx->getMachOSection("__TEXT", "__literal4",
110                            MachO::S_4BYTE_LITERALS,
111                            SectionKind::getMergeableConst4());
112   EightByteConstantSection // .literal8
113     = Ctx->getMachOSection("__TEXT", "__literal8",
114                            MachO::S_8BYTE_LITERALS,
115                            SectionKind::getMergeableConst8());
116 
117   SixteenByteConstantSection // .literal16
118       = Ctx->getMachOSection("__TEXT", "__literal16",
119                              MachO::S_16BYTE_LITERALS,
120                              SectionKind::getMergeableConst16());
121 
122   ReadOnlySection  // .const
123     = Ctx->getMachOSection("__TEXT", "__const", 0,
124                            SectionKind::getReadOnly());
125 
126   // If the target is not powerpc, map the coal sections to the non-coal
127   // sections.
128   //
129   // "__TEXT/__textcoal_nt" => section "__TEXT/__text"
130   // "__TEXT/__const_coal"  => section "__TEXT/__const"
131   // "__DATA/__datacoal_nt" => section "__DATA/__data"
132   Triple::ArchType ArchTy = T.getArch();
133 
134   ConstDataSection  // .const_data
135     = Ctx->getMachOSection("__DATA", "__const", 0,
136                            SectionKind::getReadOnlyWithRel());
137 
138   if (ArchTy == Triple::ppc || ArchTy == Triple::ppc64) {
139     TextCoalSection
140       = Ctx->getMachOSection("__TEXT", "__textcoal_nt",
141                              MachO::S_COALESCED |
142                              MachO::S_ATTR_PURE_INSTRUCTIONS,
143                              SectionKind::getText());
144     ConstTextCoalSection
145       = Ctx->getMachOSection("__TEXT", "__const_coal",
146                              MachO::S_COALESCED,
147                              SectionKind::getReadOnly());
148     DataCoalSection = Ctx->getMachOSection(
149         "__DATA", "__datacoal_nt", MachO::S_COALESCED, SectionKind::getData());
150     ConstDataCoalSection = DataCoalSection;
151   } else {
152     TextCoalSection = TextSection;
153     ConstTextCoalSection = ReadOnlySection;
154     DataCoalSection = DataSection;
155     ConstDataCoalSection = ConstDataSection;
156   }
157 
158   DataCommonSection
159     = Ctx->getMachOSection("__DATA","__common",
160                            MachO::S_ZEROFILL,
161                            SectionKind::getBSS());
162   DataBSSSection
163     = Ctx->getMachOSection("__DATA","__bss", MachO::S_ZEROFILL,
164                            SectionKind::getBSS());
165 
166 
167   LazySymbolPointerSection
168     = Ctx->getMachOSection("__DATA", "__la_symbol_ptr",
169                            MachO::S_LAZY_SYMBOL_POINTERS,
170                            SectionKind::getMetadata());
171   NonLazySymbolPointerSection
172     = Ctx->getMachOSection("__DATA", "__nl_symbol_ptr",
173                            MachO::S_NON_LAZY_SYMBOL_POINTERS,
174                            SectionKind::getMetadata());
175 
176   ThreadLocalPointerSection
177     = Ctx->getMachOSection("__DATA", "__thread_ptr",
178                            MachO::S_THREAD_LOCAL_VARIABLE_POINTERS,
179                            SectionKind::getMetadata());
180 
181   // Exception Handling.
182   LSDASection = Ctx->getMachOSection("__TEXT", "__gcc_except_tab", 0,
183                                      SectionKind::getReadOnlyWithRel());
184 
185   COFFDebugSymbolsSection = nullptr;
186   COFFDebugTypesSection = nullptr;
187   COFFGlobalTypeHashesSection = nullptr;
188 
189   if (useCompactUnwind(T)) {
190     CompactUnwindSection =
191         Ctx->getMachOSection("__LD", "__compact_unwind", MachO::S_ATTR_DEBUG,
192                              SectionKind::getReadOnly());
193 
194     if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::x86)
195       CompactUnwindDwarfEHFrameOnly = 0x04000000;  // UNWIND_X86_64_MODE_DWARF
196     else if (T.getArch() == Triple::aarch64)
197       CompactUnwindDwarfEHFrameOnly = 0x03000000;  // UNWIND_ARM64_MODE_DWARF
198     else if (T.getArch() == Triple::arm || T.getArch() == Triple::thumb)
199       CompactUnwindDwarfEHFrameOnly = 0x04000000;  // UNWIND_ARM_MODE_DWARF
200   }
201 
202   // Debug Information.
203   DwarfDebugNamesSection =
204       Ctx->getMachOSection("__DWARF", "__debug_names", MachO::S_ATTR_DEBUG,
205                            SectionKind::getMetadata(), "debug_names_begin");
206   DwarfAccelNamesSection =
207       Ctx->getMachOSection("__DWARF", "__apple_names", MachO::S_ATTR_DEBUG,
208                            SectionKind::getMetadata(), "names_begin");
209   DwarfAccelObjCSection =
210       Ctx->getMachOSection("__DWARF", "__apple_objc", MachO::S_ATTR_DEBUG,
211                            SectionKind::getMetadata(), "objc_begin");
212   // 16 character section limit...
213   DwarfAccelNamespaceSection =
214       Ctx->getMachOSection("__DWARF", "__apple_namespac", MachO::S_ATTR_DEBUG,
215                            SectionKind::getMetadata(), "namespac_begin");
216   DwarfAccelTypesSection =
217       Ctx->getMachOSection("__DWARF", "__apple_types", MachO::S_ATTR_DEBUG,
218                            SectionKind::getMetadata(), "types_begin");
219 
220   DwarfSwiftASTSection =
221       Ctx->getMachOSection("__DWARF", "__swift_ast", MachO::S_ATTR_DEBUG,
222                            SectionKind::getMetadata());
223 
224   DwarfAbbrevSection =
225       Ctx->getMachOSection("__DWARF", "__debug_abbrev", MachO::S_ATTR_DEBUG,
226                            SectionKind::getMetadata(), "section_abbrev");
227   DwarfInfoSection =
228       Ctx->getMachOSection("__DWARF", "__debug_info", MachO::S_ATTR_DEBUG,
229                            SectionKind::getMetadata(), "section_info");
230   DwarfLineSection =
231       Ctx->getMachOSection("__DWARF", "__debug_line", MachO::S_ATTR_DEBUG,
232                            SectionKind::getMetadata(), "section_line");
233   DwarfLineStrSection =
234       Ctx->getMachOSection("__DWARF", "__debug_line_str", MachO::S_ATTR_DEBUG,
235                            SectionKind::getMetadata(), "section_line_str");
236   DwarfFrameSection =
237       Ctx->getMachOSection("__DWARF", "__debug_frame", MachO::S_ATTR_DEBUG,
238                            SectionKind::getMetadata());
239   DwarfPubNamesSection =
240       Ctx->getMachOSection("__DWARF", "__debug_pubnames", MachO::S_ATTR_DEBUG,
241                            SectionKind::getMetadata());
242   DwarfPubTypesSection =
243       Ctx->getMachOSection("__DWARF", "__debug_pubtypes", MachO::S_ATTR_DEBUG,
244                            SectionKind::getMetadata());
245   DwarfGnuPubNamesSection =
246       Ctx->getMachOSection("__DWARF", "__debug_gnu_pubn", MachO::S_ATTR_DEBUG,
247                            SectionKind::getMetadata());
248   DwarfGnuPubTypesSection =
249       Ctx->getMachOSection("__DWARF", "__debug_gnu_pubt", MachO::S_ATTR_DEBUG,
250                            SectionKind::getMetadata());
251   DwarfStrSection =
252       Ctx->getMachOSection("__DWARF", "__debug_str", MachO::S_ATTR_DEBUG,
253                            SectionKind::getMetadata(), "info_string");
254   DwarfStrOffSection =
255       Ctx->getMachOSection("__DWARF", "__debug_str_offs", MachO::S_ATTR_DEBUG,
256                            SectionKind::getMetadata(), "section_str_off");
257   DwarfAddrSection =
258       Ctx->getMachOSection("__DWARF", "__debug_addr", MachO::S_ATTR_DEBUG,
259                            SectionKind::getMetadata(), "section_info");
260   DwarfLocSection =
261       Ctx->getMachOSection("__DWARF", "__debug_loc", MachO::S_ATTR_DEBUG,
262                            SectionKind::getMetadata(), "section_debug_loc");
263   DwarfLoclistsSection =
264       Ctx->getMachOSection("__DWARF", "__debug_loclists", MachO::S_ATTR_DEBUG,
265                            SectionKind::getMetadata(), "section_debug_loc");
266 
267   DwarfARangesSection =
268       Ctx->getMachOSection("__DWARF", "__debug_aranges", MachO::S_ATTR_DEBUG,
269                            SectionKind::getMetadata());
270   DwarfRangesSection =
271       Ctx->getMachOSection("__DWARF", "__debug_ranges", MachO::S_ATTR_DEBUG,
272                            SectionKind::getMetadata(), "debug_range");
273   DwarfRnglistsSection =
274       Ctx->getMachOSection("__DWARF", "__debug_rnglists", MachO::S_ATTR_DEBUG,
275                            SectionKind::getMetadata(), "debug_range");
276   DwarfMacinfoSection =
277       Ctx->getMachOSection("__DWARF", "__debug_macinfo", MachO::S_ATTR_DEBUG,
278                            SectionKind::getMetadata(), "debug_macinfo");
279   DwarfDebugInlineSection =
280       Ctx->getMachOSection("__DWARF", "__debug_inlined", MachO::S_ATTR_DEBUG,
281                            SectionKind::getMetadata());
282   DwarfCUIndexSection =
283       Ctx->getMachOSection("__DWARF", "__debug_cu_index", MachO::S_ATTR_DEBUG,
284                            SectionKind::getMetadata());
285   DwarfTUIndexSection =
286       Ctx->getMachOSection("__DWARF", "__debug_tu_index", MachO::S_ATTR_DEBUG,
287                            SectionKind::getMetadata());
288   StackMapSection = Ctx->getMachOSection("__LLVM_STACKMAPS", "__llvm_stackmaps",
289                                          0, SectionKind::getMetadata());
290 
291   FaultMapSection = Ctx->getMachOSection("__LLVM_FAULTMAPS", "__llvm_faultmaps",
292                                          0, SectionKind::getMetadata());
293 
294   RemarksSection = Ctx->getMachOSection(
295       "__LLVM", "__remarks", MachO::S_ATTR_DEBUG, SectionKind::getMetadata());
296 
297   TLSExtraDataSection = TLSTLVSection;
298 }
299 
initELFMCObjectFileInfo(const Triple & T,bool Large)300 void MCObjectFileInfo::initELFMCObjectFileInfo(const Triple &T, bool Large) {
301   switch (T.getArch()) {
302   case Triple::mips:
303   case Triple::mipsel:
304   case Triple::mips64:
305   case Triple::mips64el:
306     FDECFIEncoding = Ctx->getAsmInfo()->getCodePointerSize() == 4
307                          ? dwarf::DW_EH_PE_sdata4
308                          : dwarf::DW_EH_PE_sdata8;
309     break;
310   case Triple::ppc64:
311   case Triple::ppc64le:
312   case Triple::x86_64:
313     FDECFIEncoding = dwarf::DW_EH_PE_pcrel |
314                      (Large ? dwarf::DW_EH_PE_sdata8 : dwarf::DW_EH_PE_sdata4);
315     break;
316   case Triple::bpfel:
317   case Triple::bpfeb:
318     FDECFIEncoding = dwarf::DW_EH_PE_sdata8;
319     break;
320   case Triple::hexagon:
321     FDECFIEncoding =
322         PositionIndependent ? dwarf::DW_EH_PE_pcrel : dwarf::DW_EH_PE_absptr;
323     break;
324   default:
325     FDECFIEncoding = dwarf::DW_EH_PE_pcrel | dwarf::DW_EH_PE_sdata4;
326     break;
327   }
328 
329   unsigned EHSectionType = T.getArch() == Triple::x86_64
330                                ? ELF::SHT_X86_64_UNWIND
331                                : ELF::SHT_PROGBITS;
332 
333   // Solaris requires different flags for .eh_frame to seemingly every other
334   // platform.
335   unsigned EHSectionFlags = ELF::SHF_ALLOC;
336   if (T.isOSSolaris() && T.getArch() != Triple::x86_64)
337     EHSectionFlags |= ELF::SHF_WRITE;
338 
339   // ELF
340   BSSSection = Ctx->getELFSection(".bss", ELF::SHT_NOBITS,
341                                   ELF::SHF_WRITE | ELF::SHF_ALLOC);
342 
343   TextSection = Ctx->getELFSection(".text", ELF::SHT_PROGBITS,
344                                    ELF::SHF_EXECINSTR | ELF::SHF_ALLOC);
345 
346   DataSection = Ctx->getELFSection(".data", ELF::SHT_PROGBITS,
347                                    ELF::SHF_WRITE | ELF::SHF_ALLOC);
348 
349   ReadOnlySection =
350       Ctx->getELFSection(".rodata", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
351 
352   TLSDataSection =
353       Ctx->getELFSection(".tdata", ELF::SHT_PROGBITS,
354                          ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
355 
356   TLSBSSSection = Ctx->getELFSection(
357       ".tbss", ELF::SHT_NOBITS, ELF::SHF_ALLOC | ELF::SHF_TLS | ELF::SHF_WRITE);
358 
359   DataRelROSection = Ctx->getELFSection(".data.rel.ro", ELF::SHT_PROGBITS,
360                                         ELF::SHF_ALLOC | ELF::SHF_WRITE);
361 
362   MergeableConst4Section =
363       Ctx->getELFSection(".rodata.cst4", ELF::SHT_PROGBITS,
364                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 4, "");
365 
366   MergeableConst8Section =
367       Ctx->getELFSection(".rodata.cst8", ELF::SHT_PROGBITS,
368                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 8, "");
369 
370   MergeableConst16Section =
371       Ctx->getELFSection(".rodata.cst16", ELF::SHT_PROGBITS,
372                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 16, "");
373 
374   MergeableConst32Section =
375       Ctx->getELFSection(".rodata.cst32", ELF::SHT_PROGBITS,
376                          ELF::SHF_ALLOC | ELF::SHF_MERGE, 32, "");
377 
378   // Exception Handling Sections.
379 
380   // FIXME: We're emitting LSDA info into a readonly section on ELF, even though
381   // it contains relocatable pointers.  In PIC mode, this is probably a big
382   // runtime hit for C++ apps.  Either the contents of the LSDA need to be
383   // adjusted or this should be a data section.
384   LSDASection = Ctx->getELFSection(".gcc_except_table", ELF::SHT_PROGBITS,
385                                    ELF::SHF_ALLOC);
386 
387   COFFDebugSymbolsSection = nullptr;
388   COFFDebugTypesSection = nullptr;
389 
390   unsigned DebugSecType = ELF::SHT_PROGBITS;
391 
392   // MIPS .debug_* sections should have SHT_MIPS_DWARF section type
393   // to distinguish among sections contain DWARF and ECOFF debug formats.
394   // Sections with ECOFF debug format are obsoleted and marked by SHT_PROGBITS.
395   if (T.isMIPS())
396     DebugSecType = ELF::SHT_MIPS_DWARF;
397 
398   // Debug Info Sections.
399   DwarfAbbrevSection =
400       Ctx->getELFSection(".debug_abbrev", DebugSecType, 0);
401   DwarfInfoSection = Ctx->getELFSection(".debug_info", DebugSecType, 0);
402   DwarfLineSection = Ctx->getELFSection(".debug_line", DebugSecType, 0);
403   DwarfLineStrSection =
404       Ctx->getELFSection(".debug_line_str", DebugSecType,
405                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
406   DwarfFrameSection = Ctx->getELFSection(".debug_frame", DebugSecType, 0);
407   DwarfPubNamesSection =
408       Ctx->getELFSection(".debug_pubnames", DebugSecType, 0);
409   DwarfPubTypesSection =
410       Ctx->getELFSection(".debug_pubtypes", DebugSecType, 0);
411   DwarfGnuPubNamesSection =
412       Ctx->getELFSection(".debug_gnu_pubnames", DebugSecType, 0);
413   DwarfGnuPubTypesSection =
414       Ctx->getELFSection(".debug_gnu_pubtypes", DebugSecType, 0);
415   DwarfStrSection =
416       Ctx->getELFSection(".debug_str", DebugSecType,
417                          ELF::SHF_MERGE | ELF::SHF_STRINGS, 1, "");
418   DwarfLocSection = Ctx->getELFSection(".debug_loc", DebugSecType, 0);
419   DwarfARangesSection =
420       Ctx->getELFSection(".debug_aranges", DebugSecType, 0);
421   DwarfRangesSection =
422       Ctx->getELFSection(".debug_ranges", DebugSecType, 0);
423   DwarfMacinfoSection =
424       Ctx->getELFSection(".debug_macinfo", DebugSecType, 0);
425 
426   // DWARF5 Experimental Debug Info
427 
428   // Accelerator Tables
429   DwarfDebugNamesSection =
430       Ctx->getELFSection(".debug_names", ELF::SHT_PROGBITS, 0);
431   DwarfAccelNamesSection =
432       Ctx->getELFSection(".apple_names", ELF::SHT_PROGBITS, 0);
433   DwarfAccelObjCSection =
434       Ctx->getELFSection(".apple_objc", ELF::SHT_PROGBITS, 0);
435   DwarfAccelNamespaceSection =
436       Ctx->getELFSection(".apple_namespaces", ELF::SHT_PROGBITS, 0);
437   DwarfAccelTypesSection =
438       Ctx->getELFSection(".apple_types", ELF::SHT_PROGBITS, 0);
439 
440   // String Offset and Address Sections
441   DwarfStrOffSection =
442       Ctx->getELFSection(".debug_str_offsets", DebugSecType, 0);
443   DwarfAddrSection = Ctx->getELFSection(".debug_addr", DebugSecType, 0);
444   DwarfRnglistsSection = Ctx->getELFSection(".debug_rnglists", DebugSecType, 0);
445   DwarfLoclistsSection = Ctx->getELFSection(".debug_loclists", DebugSecType, 0);
446 
447   // Fission Sections
448   DwarfInfoDWOSection =
449       Ctx->getELFSection(".debug_info.dwo", DebugSecType, ELF::SHF_EXCLUDE);
450   DwarfTypesDWOSection =
451       Ctx->getELFSection(".debug_types.dwo", DebugSecType, ELF::SHF_EXCLUDE);
452   DwarfAbbrevDWOSection =
453       Ctx->getELFSection(".debug_abbrev.dwo", DebugSecType, ELF::SHF_EXCLUDE);
454   DwarfStrDWOSection = Ctx->getELFSection(
455       ".debug_str.dwo", DebugSecType,
456       ELF::SHF_MERGE | ELF::SHF_STRINGS | ELF::SHF_EXCLUDE, 1, "");
457   DwarfLineDWOSection =
458       Ctx->getELFSection(".debug_line.dwo", DebugSecType, ELF::SHF_EXCLUDE);
459   DwarfLocDWOSection =
460       Ctx->getELFSection(".debug_loc.dwo", DebugSecType, ELF::SHF_EXCLUDE);
461   DwarfStrOffDWOSection = Ctx->getELFSection(".debug_str_offsets.dwo",
462                                              DebugSecType, ELF::SHF_EXCLUDE);
463   DwarfRnglistsDWOSection =
464       Ctx->getELFSection(".debug_rnglists.dwo", DebugSecType, ELF::SHF_EXCLUDE);
465 
466   // DWP Sections
467   DwarfCUIndexSection =
468       Ctx->getELFSection(".debug_cu_index", DebugSecType, 0);
469   DwarfTUIndexSection =
470       Ctx->getELFSection(".debug_tu_index", DebugSecType, 0);
471 
472   StackMapSection =
473       Ctx->getELFSection(".llvm_stackmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
474 
475   FaultMapSection =
476       Ctx->getELFSection(".llvm_faultmaps", ELF::SHT_PROGBITS, ELF::SHF_ALLOC);
477 
478   EHFrameSection =
479       Ctx->getELFSection(".eh_frame", EHSectionType, EHSectionFlags);
480 
481   StackSizesSection = Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, 0);
482 
483   RemarksSection =
484       Ctx->getELFSection(".remarks", ELF::SHT_PROGBITS, ELF::SHF_EXCLUDE);
485 }
486 
initCOFFMCObjectFileInfo(const Triple & T)487 void MCObjectFileInfo::initCOFFMCObjectFileInfo(const Triple &T) {
488   EHFrameSection =
489       Ctx->getCOFFSection(".eh_frame", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
490                                            COFF::IMAGE_SCN_MEM_READ,
491                           SectionKind::getData());
492 
493   // Set the `IMAGE_SCN_MEM_16BIT` flag when compiling for thumb mode.  This is
494   // used to indicate to the linker that the text segment contains thumb instructions
495   // and to set the ISA selection bit for calls accordingly.
496   const bool IsThumb = T.getArch() == Triple::thumb;
497 
498   CommDirectiveSupportsAlignment = true;
499 
500   // COFF
501   BSSSection = Ctx->getCOFFSection(
502       ".bss", COFF::IMAGE_SCN_CNT_UNINITIALIZED_DATA |
503                   COFF::IMAGE_SCN_MEM_READ | COFF::IMAGE_SCN_MEM_WRITE,
504       SectionKind::getBSS());
505   TextSection = Ctx->getCOFFSection(
506       ".text",
507       (IsThumb ? COFF::IMAGE_SCN_MEM_16BIT : (COFF::SectionCharacteristics)0) |
508           COFF::IMAGE_SCN_CNT_CODE | COFF::IMAGE_SCN_MEM_EXECUTE |
509           COFF::IMAGE_SCN_MEM_READ,
510       SectionKind::getText());
511   DataSection = Ctx->getCOFFSection(
512       ".data", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
513                    COFF::IMAGE_SCN_MEM_WRITE,
514       SectionKind::getData());
515   ReadOnlySection = Ctx->getCOFFSection(
516       ".rdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
517       SectionKind::getReadOnly());
518 
519   if (T.getArch() == Triple::x86_64 || T.getArch() == Triple::aarch64) {
520     // On Windows 64 with SEH, the LSDA is emitted into the .xdata section
521     LSDASection = nullptr;
522   } else {
523     LSDASection = Ctx->getCOFFSection(".gcc_except_table",
524                                       COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
525                                           COFF::IMAGE_SCN_MEM_READ,
526                                       SectionKind::getReadOnly());
527   }
528 
529   // Debug info.
530   COFFDebugSymbolsSection =
531       Ctx->getCOFFSection(".debug$S", (COFF::IMAGE_SCN_MEM_DISCARDABLE |
532                                        COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
533                                        COFF::IMAGE_SCN_MEM_READ),
534                           SectionKind::getMetadata());
535   COFFDebugTypesSection =
536       Ctx->getCOFFSection(".debug$T", (COFF::IMAGE_SCN_MEM_DISCARDABLE |
537                                        COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
538                                        COFF::IMAGE_SCN_MEM_READ),
539                           SectionKind::getMetadata());
540   COFFGlobalTypeHashesSection = Ctx->getCOFFSection(
541       ".debug$H",
542       (COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
543        COFF::IMAGE_SCN_MEM_READ),
544       SectionKind::getMetadata());
545 
546   DwarfAbbrevSection = Ctx->getCOFFSection(
547       ".debug_abbrev",
548       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
549           COFF::IMAGE_SCN_MEM_READ,
550       SectionKind::getMetadata(), "section_abbrev");
551   DwarfInfoSection = Ctx->getCOFFSection(
552       ".debug_info",
553       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
554           COFF::IMAGE_SCN_MEM_READ,
555       SectionKind::getMetadata(), "section_info");
556   DwarfLineSection = Ctx->getCOFFSection(
557       ".debug_line",
558       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
559           COFF::IMAGE_SCN_MEM_READ,
560       SectionKind::getMetadata(), "section_line");
561   DwarfLineStrSection = Ctx->getCOFFSection(
562       ".debug_line_str",
563       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
564           COFF::IMAGE_SCN_MEM_READ,
565       SectionKind::getMetadata(), "section_line_str");
566   DwarfFrameSection = Ctx->getCOFFSection(
567       ".debug_frame",
568       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
569           COFF::IMAGE_SCN_MEM_READ,
570       SectionKind::getMetadata());
571   DwarfPubNamesSection = Ctx->getCOFFSection(
572       ".debug_pubnames",
573       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
574           COFF::IMAGE_SCN_MEM_READ,
575       SectionKind::getMetadata());
576   DwarfPubTypesSection = Ctx->getCOFFSection(
577       ".debug_pubtypes",
578       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
579           COFF::IMAGE_SCN_MEM_READ,
580       SectionKind::getMetadata());
581   DwarfGnuPubNamesSection = Ctx->getCOFFSection(
582       ".debug_gnu_pubnames",
583       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
584           COFF::IMAGE_SCN_MEM_READ,
585       SectionKind::getMetadata());
586   DwarfGnuPubTypesSection = Ctx->getCOFFSection(
587       ".debug_gnu_pubtypes",
588       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
589           COFF::IMAGE_SCN_MEM_READ,
590       SectionKind::getMetadata());
591   DwarfStrSection = Ctx->getCOFFSection(
592       ".debug_str",
593       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
594           COFF::IMAGE_SCN_MEM_READ,
595       SectionKind::getMetadata(), "info_string");
596   DwarfStrOffSection = Ctx->getCOFFSection(
597       ".debug_str_offsets",
598       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
599           COFF::IMAGE_SCN_MEM_READ,
600       SectionKind::getMetadata(), "section_str_off");
601   DwarfLocSection = Ctx->getCOFFSection(
602       ".debug_loc",
603       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
604           COFF::IMAGE_SCN_MEM_READ,
605       SectionKind::getMetadata(), "section_debug_loc");
606   DwarfARangesSection = Ctx->getCOFFSection(
607       ".debug_aranges",
608       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
609           COFF::IMAGE_SCN_MEM_READ,
610       SectionKind::getMetadata());
611   DwarfRangesSection = Ctx->getCOFFSection(
612       ".debug_ranges",
613       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
614           COFF::IMAGE_SCN_MEM_READ,
615       SectionKind::getMetadata(), "debug_range");
616   DwarfMacinfoSection = Ctx->getCOFFSection(
617       ".debug_macinfo",
618       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
619           COFF::IMAGE_SCN_MEM_READ,
620       SectionKind::getMetadata(), "debug_macinfo");
621   DwarfInfoDWOSection = Ctx->getCOFFSection(
622       ".debug_info.dwo",
623       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
624           COFF::IMAGE_SCN_MEM_READ,
625       SectionKind::getMetadata(), "section_info_dwo");
626   DwarfTypesDWOSection = Ctx->getCOFFSection(
627       ".debug_types.dwo",
628       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
629           COFF::IMAGE_SCN_MEM_READ,
630       SectionKind::getMetadata(), "section_types_dwo");
631   DwarfAbbrevDWOSection = Ctx->getCOFFSection(
632       ".debug_abbrev.dwo",
633       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
634           COFF::IMAGE_SCN_MEM_READ,
635       SectionKind::getMetadata(), "section_abbrev_dwo");
636   DwarfStrDWOSection = Ctx->getCOFFSection(
637       ".debug_str.dwo",
638       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
639           COFF::IMAGE_SCN_MEM_READ,
640       SectionKind::getMetadata(), "skel_string");
641   DwarfLineDWOSection = Ctx->getCOFFSection(
642       ".debug_line.dwo",
643       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
644           COFF::IMAGE_SCN_MEM_READ,
645       SectionKind::getMetadata());
646   DwarfLocDWOSection = Ctx->getCOFFSection(
647       ".debug_loc.dwo",
648       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
649           COFF::IMAGE_SCN_MEM_READ,
650       SectionKind::getMetadata(), "skel_loc");
651   DwarfStrOffDWOSection = Ctx->getCOFFSection(
652       ".debug_str_offsets.dwo",
653       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
654           COFF::IMAGE_SCN_MEM_READ,
655       SectionKind::getMetadata(), "section_str_off_dwo");
656   DwarfAddrSection = Ctx->getCOFFSection(
657       ".debug_addr",
658       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
659           COFF::IMAGE_SCN_MEM_READ,
660       SectionKind::getMetadata(), "addr_sec");
661   DwarfCUIndexSection = Ctx->getCOFFSection(
662       ".debug_cu_index",
663       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
664           COFF::IMAGE_SCN_MEM_READ,
665       SectionKind::getMetadata());
666   DwarfTUIndexSection = Ctx->getCOFFSection(
667       ".debug_tu_index",
668       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
669           COFF::IMAGE_SCN_MEM_READ,
670       SectionKind::getMetadata());
671   DwarfDebugNamesSection = Ctx->getCOFFSection(
672       ".debug_names",
673       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
674           COFF::IMAGE_SCN_MEM_READ,
675       SectionKind::getMetadata(), "debug_names_begin");
676   DwarfAccelNamesSection = Ctx->getCOFFSection(
677       ".apple_names",
678       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
679           COFF::IMAGE_SCN_MEM_READ,
680       SectionKind::getMetadata(), "names_begin");
681   DwarfAccelNamespaceSection = Ctx->getCOFFSection(
682       ".apple_namespaces",
683       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
684           COFF::IMAGE_SCN_MEM_READ,
685       SectionKind::getMetadata(), "namespac_begin");
686   DwarfAccelTypesSection = Ctx->getCOFFSection(
687       ".apple_types",
688       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
689           COFF::IMAGE_SCN_MEM_READ,
690       SectionKind::getMetadata(), "types_begin");
691   DwarfAccelObjCSection = Ctx->getCOFFSection(
692       ".apple_objc",
693       COFF::IMAGE_SCN_MEM_DISCARDABLE | COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
694           COFF::IMAGE_SCN_MEM_READ,
695       SectionKind::getMetadata(), "objc_begin");
696 
697   DrectveSection = Ctx->getCOFFSection(
698       ".drectve", COFF::IMAGE_SCN_LNK_INFO | COFF::IMAGE_SCN_LNK_REMOVE,
699       SectionKind::getMetadata());
700 
701   PDataSection = Ctx->getCOFFSection(
702       ".pdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
703       SectionKind::getData());
704 
705   XDataSection = Ctx->getCOFFSection(
706       ".xdata", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ,
707       SectionKind::getData());
708 
709   SXDataSection = Ctx->getCOFFSection(".sxdata", COFF::IMAGE_SCN_LNK_INFO,
710                                       SectionKind::getMetadata());
711 
712   GFIDsSection = Ctx->getCOFFSection(".gfids$y",
713                                      COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
714                                          COFF::IMAGE_SCN_MEM_READ,
715                                      SectionKind::getMetadata());
716 
717   TLSDataSection = Ctx->getCOFFSection(
718       ".tls$", COFF::IMAGE_SCN_CNT_INITIALIZED_DATA | COFF::IMAGE_SCN_MEM_READ |
719                    COFF::IMAGE_SCN_MEM_WRITE,
720       SectionKind::getData());
721 
722   StackMapSection = Ctx->getCOFFSection(".llvm_stackmaps",
723                                         COFF::IMAGE_SCN_CNT_INITIALIZED_DATA |
724                                             COFF::IMAGE_SCN_MEM_READ,
725                                         SectionKind::getReadOnly());
726 }
727 
initWasmMCObjectFileInfo(const Triple & T)728 void MCObjectFileInfo::initWasmMCObjectFileInfo(const Triple &T) {
729   TextSection = Ctx->getWasmSection(".text", SectionKind::getText());
730   DataSection = Ctx->getWasmSection(".data", SectionKind::getData());
731 
732   DwarfLineSection =
733       Ctx->getWasmSection(".debug_line", SectionKind::getMetadata());
734   DwarfLineStrSection =
735       Ctx->getWasmSection(".debug_line_str", SectionKind::getMetadata());
736   DwarfStrSection =
737       Ctx->getWasmSection(".debug_str", SectionKind::getMetadata());
738   DwarfLocSection =
739       Ctx->getWasmSection(".debug_loc", SectionKind::getMetadata());
740   DwarfAbbrevSection =
741       Ctx->getWasmSection(".debug_abbrev", SectionKind::getMetadata());
742   DwarfARangesSection = Ctx->getWasmSection(".debug_aranges", SectionKind::getMetadata());
743   DwarfRangesSection =
744       Ctx->getWasmSection(".debug_ranges", SectionKind::getMetadata());
745   DwarfMacinfoSection =
746       Ctx->getWasmSection(".debug_macinfo", SectionKind::getMetadata());
747   DwarfAddrSection = Ctx->getWasmSection(".debug_addr", SectionKind::getMetadata());
748   DwarfCUIndexSection = Ctx->getWasmSection(".debug_cu_index", SectionKind::getMetadata());
749   DwarfTUIndexSection = Ctx->getWasmSection(".debug_tu_index", SectionKind::getMetadata());
750   DwarfInfoSection =
751       Ctx->getWasmSection(".debug_info", SectionKind::getMetadata());
752   DwarfFrameSection = Ctx->getWasmSection(".debug_frame", SectionKind::getMetadata());
753   DwarfPubNamesSection = Ctx->getWasmSection(".debug_pubnames", SectionKind::getMetadata());
754   DwarfPubTypesSection = Ctx->getWasmSection(".debug_pubtypes", SectionKind::getMetadata());
755 
756   // Wasm use data section for LSDA.
757   // TODO Consider putting each function's exception table in a separate
758   // section, as in -function-sections, to facilitate lld's --gc-section.
759   LSDASection = Ctx->getWasmSection(".rodata.gcc_except_table",
760                                     SectionKind::getReadOnlyWithRel());
761 
762   // TODO: Define more sections.
763 }
764 
initXCOFFMCObjectFileInfo(const Triple & T)765 void MCObjectFileInfo::initXCOFFMCObjectFileInfo(const Triple &T) {
766   // The default csect for program code. Functions without a specified section
767   // get placed into this csect. The choice of csect name is not a property of
768   // the ABI or object file format. For example, the XL compiler uses an unnamed
769   // csect for program code.
770   TextSection = Ctx->getXCOFFSection(
771       ".text", XCOFF::StorageMappingClass::XMC_PR, SectionKind::getText());
772 }
773 
InitMCObjectFileInfo(const Triple & TheTriple,bool PIC,MCContext & ctx,bool LargeCodeModel)774 void MCObjectFileInfo::InitMCObjectFileInfo(const Triple &TheTriple, bool PIC,
775                                             MCContext &ctx,
776                                             bool LargeCodeModel) {
777   PositionIndependent = PIC;
778   Ctx = &ctx;
779 
780   // Common.
781   CommDirectiveSupportsAlignment = true;
782   SupportsWeakOmittedEHFrame = true;
783   SupportsCompactUnwindWithoutEHFrame = false;
784   OmitDwarfIfHaveCompactUnwind = false;
785 
786   FDECFIEncoding = dwarf::DW_EH_PE_absptr;
787 
788   CompactUnwindDwarfEHFrameOnly = 0;
789 
790   EHFrameSection = nullptr;             // Created on demand.
791   CompactUnwindSection = nullptr;       // Used only by selected targets.
792   DwarfAccelNamesSection = nullptr;     // Used only by selected targets.
793   DwarfAccelObjCSection = nullptr;      // Used only by selected targets.
794   DwarfAccelNamespaceSection = nullptr; // Used only by selected targets.
795   DwarfAccelTypesSection = nullptr;     // Used only by selected targets.
796 
797   TT = TheTriple;
798 
799   switch (TT.getObjectFormat()) {
800   case Triple::MachO:
801     Env = IsMachO;
802     initMachOMCObjectFileInfo(TT);
803     break;
804   case Triple::COFF:
805     if (!TT.isOSWindows())
806       report_fatal_error(
807           "Cannot initialize MC for non-Windows COFF object files.");
808 
809     Env = IsCOFF;
810     initCOFFMCObjectFileInfo(TT);
811     break;
812   case Triple::ELF:
813     Env = IsELF;
814     initELFMCObjectFileInfo(TT, LargeCodeModel);
815     break;
816   case Triple::Wasm:
817     Env = IsWasm;
818     initWasmMCObjectFileInfo(TT);
819     break;
820   case Triple::XCOFF:
821     Env = IsXCOFF;
822     initXCOFFMCObjectFileInfo(TT);
823     break;
824   case Triple::UnknownObjectFormat:
825     report_fatal_error("Cannot initialize MC for unknown object file format.");
826     break;
827   }
828 }
829 
getDwarfComdatSection(const char * Name,uint64_t Hash) const830 MCSection *MCObjectFileInfo::getDwarfComdatSection(const char *Name,
831                                                    uint64_t Hash) const {
832   switch (TT.getObjectFormat()) {
833   case Triple::ELF:
834     return Ctx->getELFSection(Name, ELF::SHT_PROGBITS, ELF::SHF_GROUP, 0,
835                               utostr(Hash));
836   case Triple::MachO:
837   case Triple::COFF:
838   case Triple::Wasm:
839   case Triple::XCOFF:
840   case Triple::UnknownObjectFormat:
841     report_fatal_error("Cannot get DWARF comdat section for this object file "
842                        "format: not implemented.");
843     break;
844   }
845   llvm_unreachable("Unknown ObjectFormatType");
846 }
847 
848 MCSection *
getStackSizesSection(const MCSection & TextSec) const849 MCObjectFileInfo::getStackSizesSection(const MCSection &TextSec) const {
850   if (Env != IsELF)
851     return StackSizesSection;
852 
853   const MCSectionELF &ElfSec = static_cast<const MCSectionELF &>(TextSec);
854   unsigned Flags = ELF::SHF_LINK_ORDER;
855   StringRef GroupName;
856   if (const MCSymbol *Group = ElfSec.getGroup()) {
857     GroupName = Group->getName();
858     Flags |= ELF::SHF_GROUP;
859   }
860 
861   const MCSymbol *Link = TextSec.getBeginSymbol();
862   auto It = StackSizesUniquing.insert({Link, StackSizesUniquing.size()});
863   unsigned UniqueID = It.first->second;
864 
865   return Ctx->getELFSection(".stack_sizes", ELF::SHT_PROGBITS, Flags, 0,
866                             GroupName, UniqueID, cast<MCSymbolELF>(Link));
867 }
868