1 //===- DarwinAsmParser.cpp - Darwin (Mach-O) Assembly Parser --------------===//
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/ADT/STLExtras.h"
11 #include "llvm/ADT/SmallVector.h"
12 #include "llvm/ADT/StringRef.h"
13 #include "llvm/ADT/StringSwitch.h"
14 #include "llvm/ADT/Triple.h"
15 #include "llvm/ADT/Twine.h"
16 #include "llvm/BinaryFormat/MachO.h"
17 #include "llvm/MC/MCContext.h"
18 #include "llvm/MC/MCDirectives.h"
19 #include "llvm/MC/MCObjectFileInfo.h"
20 #include "llvm/MC/MCParser/MCAsmLexer.h"
21 #include "llvm/MC/MCParser/MCAsmParser.h"
22 #include "llvm/MC/MCParser/MCAsmParserExtension.h"
23 #include "llvm/MC/MCSectionMachO.h"
24 #include "llvm/MC/MCStreamer.h"
25 #include "llvm/MC/MCSymbol.h"
26 #include "llvm/MC/SectionKind.h"
27 #include "llvm/Support/FileSystem.h"
28 #include "llvm/Support/MemoryBuffer.h"
29 #include "llvm/Support/SMLoc.h"
30 #include "llvm/Support/SourceMgr.h"
31 #include "llvm/Support/raw_ostream.h"
32 #include <algorithm>
33 #include <cstddef>
34 #include <cstdint>
35 #include <string>
36 #include <system_error>
37 #include <utility>
38 
39 using namespace llvm;
40 
41 namespace {
42 
43 /// Implementation of directive handling which is shared across all
44 /// Darwin targets.
45 class DarwinAsmParser : public MCAsmParserExtension {
46   template<bool (DarwinAsmParser::*HandlerMethod)(StringRef, SMLoc)>
47   void addDirectiveHandler(StringRef Directive) {
48     MCAsmParser::ExtensionDirectiveHandler Handler = std::make_pair(
49         this, HandleDirective<DarwinAsmParser, HandlerMethod>);
50     getParser().addDirectiveHandler(Directive, Handler);
51   }
52 
53   bool parseSectionSwitch(StringRef Segment, StringRef Section,
54                           unsigned TAA = 0, unsigned ImplicitAlign = 0,
55                           unsigned StubSize = 0);
56 
57   SMLoc LastVersionDirective;
58 
59 public:
60   DarwinAsmParser() = default;
61 
62   void Initialize(MCAsmParser &Parser) override {
63     // Call the base implementation.
64     this->MCAsmParserExtension::Initialize(Parser);
65 
66     addDirectiveHandler<&DarwinAsmParser::parseDirectiveAltEntry>(".alt_entry");
67     addDirectiveHandler<&DarwinAsmParser::parseDirectiveDesc>(".desc");
68     addDirectiveHandler<&DarwinAsmParser::parseDirectiveIndirectSymbol>(
69       ".indirect_symbol");
70     addDirectiveHandler<&DarwinAsmParser::parseDirectiveLsym>(".lsym");
71     addDirectiveHandler<&DarwinAsmParser::parseDirectiveSubsectionsViaSymbols>(
72       ".subsections_via_symbols");
73     addDirectiveHandler<&DarwinAsmParser::parseDirectiveDumpOrLoad>(".dump");
74     addDirectiveHandler<&DarwinAsmParser::parseDirectiveDumpOrLoad>(".load");
75     addDirectiveHandler<&DarwinAsmParser::parseDirectiveSection>(".section");
76     addDirectiveHandler<&DarwinAsmParser::parseDirectivePushSection>(
77       ".pushsection");
78     addDirectiveHandler<&DarwinAsmParser::parseDirectivePopSection>(
79       ".popsection");
80     addDirectiveHandler<&DarwinAsmParser::parseDirectivePrevious>(".previous");
81     addDirectiveHandler<&DarwinAsmParser::parseDirectiveSecureLogUnique>(
82       ".secure_log_unique");
83     addDirectiveHandler<&DarwinAsmParser::parseDirectiveSecureLogReset>(
84       ".secure_log_reset");
85     addDirectiveHandler<&DarwinAsmParser::parseDirectiveTBSS>(".tbss");
86     addDirectiveHandler<&DarwinAsmParser::parseDirectiveZerofill>(".zerofill");
87 
88     addDirectiveHandler<&DarwinAsmParser::parseDirectiveDataRegion>(
89       ".data_region");
90     addDirectiveHandler<&DarwinAsmParser::parseDirectiveDataRegionEnd>(
91       ".end_data_region");
92 
93     // Special section directives.
94     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveBss>(".bss");
95     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveConst>(".const");
96     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveConstData>(
97       ".const_data");
98     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveConstructor>(
99       ".constructor");
100     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveCString>(
101       ".cstring");
102     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveData>(".data");
103     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveDestructor>(
104       ".destructor");
105     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveDyld>(".dyld");
106     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveFVMLibInit0>(
107       ".fvmlib_init0");
108     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveFVMLibInit1>(
109       ".fvmlib_init1");
110     addDirectiveHandler<
111       &DarwinAsmParser::parseSectionDirectiveLazySymbolPointers>(
112         ".lazy_symbol_pointer");
113     addDirectiveHandler<&DarwinAsmParser::parseDirectiveLinkerOption>(
114       ".linker_option");
115     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveLiteral16>(
116       ".literal16");
117     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveLiteral4>(
118       ".literal4");
119     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveLiteral8>(
120       ".literal8");
121     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveModInitFunc>(
122       ".mod_init_func");
123     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveModTermFunc>(
124       ".mod_term_func");
125     addDirectiveHandler<
126       &DarwinAsmParser::parseSectionDirectiveNonLazySymbolPointers>(
127         ".non_lazy_symbol_pointer");
128     addDirectiveHandler<
129       &DarwinAsmParser::parseSectionDirectiveThreadLocalVariablePointers>(
130         ".thread_local_variable_pointer");
131     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveObjCCatClsMeth>(
132       ".objc_cat_cls_meth");
133     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveObjCCatInstMeth>(
134       ".objc_cat_inst_meth");
135     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveObjCCategory>(
136       ".objc_category");
137     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveObjCClass>(
138       ".objc_class");
139     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveObjCClassNames>(
140       ".objc_class_names");
141     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveObjCClassVars>(
142       ".objc_class_vars");
143     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveObjCClsMeth>(
144       ".objc_cls_meth");
145     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveObjCClsRefs>(
146       ".objc_cls_refs");
147     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveObjCInstMeth>(
148       ".objc_inst_meth");
149     addDirectiveHandler<
150       &DarwinAsmParser::parseSectionDirectiveObjCInstanceVars>(
151         ".objc_instance_vars");
152     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveObjCMessageRefs>(
153       ".objc_message_refs");
154     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveObjCMetaClass>(
155       ".objc_meta_class");
156     addDirectiveHandler<
157       &DarwinAsmParser::parseSectionDirectiveObjCMethVarNames>(
158         ".objc_meth_var_names");
159     addDirectiveHandler<
160       &DarwinAsmParser::parseSectionDirectiveObjCMethVarTypes>(
161         ".objc_meth_var_types");
162     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveObjCModuleInfo>(
163       ".objc_module_info");
164     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveObjCProtocol>(
165       ".objc_protocol");
166     addDirectiveHandler<
167       &DarwinAsmParser::parseSectionDirectiveObjCSelectorStrs>(
168         ".objc_selector_strs");
169     addDirectiveHandler<
170       &DarwinAsmParser::parseSectionDirectiveObjCStringObject>(
171         ".objc_string_object");
172     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveObjCSymbols>(
173       ".objc_symbols");
174     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectivePICSymbolStub>(
175       ".picsymbol_stub");
176     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveStaticConst>(
177       ".static_const");
178     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveStaticData>(
179       ".static_data");
180     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveSymbolStub>(
181       ".symbol_stub");
182     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveTData>(".tdata");
183     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveText>(".text");
184     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveThreadInitFunc>(
185       ".thread_init_func");
186     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveTLV>(".tlv");
187 
188     addDirectiveHandler<&DarwinAsmParser::parseSectionDirectiveIdent>(".ident");
189     addDirectiveHandler<&DarwinAsmParser::parseWatchOSVersionMin>(
190       ".watchos_version_min");
191     addDirectiveHandler<&DarwinAsmParser::parseTvOSVersionMin>(
192       ".tvos_version_min");
193     addDirectiveHandler<&DarwinAsmParser::parseIOSVersionMin>(
194       ".ios_version_min");
195     addDirectiveHandler<&DarwinAsmParser::parseMacOSXVersionMin>(
196       ".macosx_version_min");
197     addDirectiveHandler<&DarwinAsmParser::parseBuildVersion>(".build_version");
198 
199     LastVersionDirective = SMLoc();
200   }
201 
202   bool parseDirectiveAltEntry(StringRef, SMLoc);
203   bool parseDirectiveDesc(StringRef, SMLoc);
204   bool parseDirectiveIndirectSymbol(StringRef, SMLoc);
205   bool parseDirectiveDumpOrLoad(StringRef, SMLoc);
206   bool parseDirectiveLsym(StringRef, SMLoc);
207   bool parseDirectiveLinkerOption(StringRef, SMLoc);
208   bool parseDirectiveSection(StringRef, SMLoc);
209   bool parseDirectivePushSection(StringRef, SMLoc);
210   bool parseDirectivePopSection(StringRef, SMLoc);
211   bool parseDirectivePrevious(StringRef, SMLoc);
212   bool parseDirectiveSecureLogReset(StringRef, SMLoc);
213   bool parseDirectiveSecureLogUnique(StringRef, SMLoc);
214   bool parseDirectiveSubsectionsViaSymbols(StringRef, SMLoc);
215   bool parseDirectiveTBSS(StringRef, SMLoc);
216   bool parseDirectiveZerofill(StringRef, SMLoc);
217   bool parseDirectiveDataRegion(StringRef, SMLoc);
218   bool parseDirectiveDataRegionEnd(StringRef, SMLoc);
219 
220   // Named Section Directive
221   bool parseSectionDirectiveBss(StringRef, SMLoc) {
222     return parseSectionSwitch("__DATA", "__bss");
223   }
224 
225   bool parseSectionDirectiveConst(StringRef, SMLoc) {
226     return parseSectionSwitch("__TEXT", "__const");
227   }
228 
229   bool parseSectionDirectiveStaticConst(StringRef, SMLoc) {
230     return parseSectionSwitch("__TEXT", "__static_const");
231   }
232 
233   bool parseSectionDirectiveCString(StringRef, SMLoc) {
234     return parseSectionSwitch("__TEXT","__cstring",
235                               MachO::S_CSTRING_LITERALS);
236   }
237 
238   bool parseSectionDirectiveLiteral4(StringRef, SMLoc) {
239     return parseSectionSwitch("__TEXT", "__literal4",
240                               MachO::S_4BYTE_LITERALS, 4);
241   }
242 
243   bool parseSectionDirectiveLiteral8(StringRef, SMLoc) {
244     return parseSectionSwitch("__TEXT", "__literal8",
245                               MachO::S_8BYTE_LITERALS, 8);
246   }
247 
248   bool parseSectionDirectiveLiteral16(StringRef, SMLoc) {
249     return parseSectionSwitch("__TEXT","__literal16",
250                               MachO::S_16BYTE_LITERALS, 16);
251   }
252 
253   bool parseSectionDirectiveConstructor(StringRef, SMLoc) {
254     return parseSectionSwitch("__TEXT","__constructor");
255   }
256 
257   bool parseSectionDirectiveDestructor(StringRef, SMLoc) {
258     return parseSectionSwitch("__TEXT","__destructor");
259   }
260 
261   bool parseSectionDirectiveFVMLibInit0(StringRef, SMLoc) {
262     return parseSectionSwitch("__TEXT","__fvmlib_init0");
263   }
264 
265   bool parseSectionDirectiveFVMLibInit1(StringRef, SMLoc) {
266     return parseSectionSwitch("__TEXT","__fvmlib_init1");
267   }
268 
269   bool parseSectionDirectiveSymbolStub(StringRef, SMLoc) {
270     return parseSectionSwitch("__TEXT","__symbol_stub",
271                               MachO::S_SYMBOL_STUBS |
272                               MachO::S_ATTR_PURE_INSTRUCTIONS,
273                               // FIXME: Different on PPC and ARM.
274                               0, 16);
275   }
276 
277   bool parseSectionDirectivePICSymbolStub(StringRef, SMLoc) {
278     return parseSectionSwitch("__TEXT","__picsymbol_stub",
279                               MachO::S_SYMBOL_STUBS |
280                               MachO::S_ATTR_PURE_INSTRUCTIONS, 0, 26);
281   }
282 
283   bool parseSectionDirectiveData(StringRef, SMLoc) {
284     return parseSectionSwitch("__DATA", "__data");
285   }
286 
287   bool parseSectionDirectiveStaticData(StringRef, SMLoc) {
288     return parseSectionSwitch("__DATA", "__static_data");
289   }
290 
291   bool parseSectionDirectiveNonLazySymbolPointers(StringRef, SMLoc) {
292     return parseSectionSwitch("__DATA", "__nl_symbol_ptr",
293                               MachO::S_NON_LAZY_SYMBOL_POINTERS, 4);
294   }
295 
296   bool parseSectionDirectiveLazySymbolPointers(StringRef, SMLoc) {
297     return parseSectionSwitch("__DATA", "__la_symbol_ptr",
298                               MachO::S_LAZY_SYMBOL_POINTERS, 4);
299   }
300 
301   bool parseSectionDirectiveThreadLocalVariablePointers(StringRef, SMLoc) {
302     return parseSectionSwitch("__DATA", "__thread_ptr",
303                               MachO::S_THREAD_LOCAL_VARIABLE_POINTERS, 4);
304   }
305 
306   bool parseSectionDirectiveDyld(StringRef, SMLoc) {
307     return parseSectionSwitch("__DATA", "__dyld");
308   }
309 
310   bool parseSectionDirectiveModInitFunc(StringRef, SMLoc) {
311     return parseSectionSwitch("__DATA", "__mod_init_func",
312                               MachO::S_MOD_INIT_FUNC_POINTERS, 4);
313   }
314 
315   bool parseSectionDirectiveModTermFunc(StringRef, SMLoc) {
316     return parseSectionSwitch("__DATA", "__mod_term_func",
317                               MachO::S_MOD_TERM_FUNC_POINTERS, 4);
318   }
319 
320   bool parseSectionDirectiveConstData(StringRef, SMLoc) {
321     return parseSectionSwitch("__DATA", "__const");
322   }
323 
324   bool parseSectionDirectiveObjCClass(StringRef, SMLoc) {
325     return parseSectionSwitch("__OBJC", "__class",
326                               MachO::S_ATTR_NO_DEAD_STRIP);
327   }
328 
329   bool parseSectionDirectiveObjCMetaClass(StringRef, SMLoc) {
330     return parseSectionSwitch("__OBJC", "__meta_class",
331                               MachO::S_ATTR_NO_DEAD_STRIP);
332   }
333 
334   bool parseSectionDirectiveObjCCatClsMeth(StringRef, SMLoc) {
335     return parseSectionSwitch("__OBJC", "__cat_cls_meth",
336                               MachO::S_ATTR_NO_DEAD_STRIP);
337   }
338 
339   bool parseSectionDirectiveObjCCatInstMeth(StringRef, SMLoc) {
340     return parseSectionSwitch("__OBJC", "__cat_inst_meth",
341                               MachO::S_ATTR_NO_DEAD_STRIP);
342   }
343 
344   bool parseSectionDirectiveObjCProtocol(StringRef, SMLoc) {
345     return parseSectionSwitch("__OBJC", "__protocol",
346                               MachO::S_ATTR_NO_DEAD_STRIP);
347   }
348 
349   bool parseSectionDirectiveObjCStringObject(StringRef, SMLoc) {
350     return parseSectionSwitch("__OBJC", "__string_object",
351                               MachO::S_ATTR_NO_DEAD_STRIP);
352   }
353 
354   bool parseSectionDirectiveObjCClsMeth(StringRef, SMLoc) {
355     return parseSectionSwitch("__OBJC", "__cls_meth",
356                               MachO::S_ATTR_NO_DEAD_STRIP);
357   }
358 
359   bool parseSectionDirectiveObjCInstMeth(StringRef, SMLoc) {
360     return parseSectionSwitch("__OBJC", "__inst_meth",
361                               MachO::S_ATTR_NO_DEAD_STRIP);
362   }
363 
364   bool parseSectionDirectiveObjCClsRefs(StringRef, SMLoc) {
365     return parseSectionSwitch("__OBJC", "__cls_refs",
366                               MachO::S_ATTR_NO_DEAD_STRIP |
367                               MachO::S_LITERAL_POINTERS, 4);
368   }
369 
370   bool parseSectionDirectiveObjCMessageRefs(StringRef, SMLoc) {
371     return parseSectionSwitch("__OBJC", "__message_refs",
372                               MachO::S_ATTR_NO_DEAD_STRIP |
373                               MachO::S_LITERAL_POINTERS, 4);
374   }
375 
376   bool parseSectionDirectiveObjCSymbols(StringRef, SMLoc) {
377     return parseSectionSwitch("__OBJC", "__symbols",
378                               MachO::S_ATTR_NO_DEAD_STRIP);
379   }
380 
381   bool parseSectionDirectiveObjCCategory(StringRef, SMLoc) {
382     return parseSectionSwitch("__OBJC", "__category",
383                               MachO::S_ATTR_NO_DEAD_STRIP);
384   }
385 
386   bool parseSectionDirectiveObjCClassVars(StringRef, SMLoc) {
387     return parseSectionSwitch("__OBJC", "__class_vars",
388                               MachO::S_ATTR_NO_DEAD_STRIP);
389   }
390 
391   bool parseSectionDirectiveObjCInstanceVars(StringRef, SMLoc) {
392     return parseSectionSwitch("__OBJC", "__instance_vars",
393                               MachO::S_ATTR_NO_DEAD_STRIP);
394   }
395 
396   bool parseSectionDirectiveObjCModuleInfo(StringRef, SMLoc) {
397     return parseSectionSwitch("__OBJC", "__module_info",
398                               MachO::S_ATTR_NO_DEAD_STRIP);
399   }
400 
401   bool parseSectionDirectiveObjCClassNames(StringRef, SMLoc) {
402     return parseSectionSwitch("__TEXT", "__cstring",
403                               MachO::S_CSTRING_LITERALS);
404   }
405 
406   bool parseSectionDirectiveObjCMethVarTypes(StringRef, SMLoc) {
407     return parseSectionSwitch("__TEXT", "__cstring",
408                               MachO::S_CSTRING_LITERALS);
409   }
410 
411   bool parseSectionDirectiveObjCMethVarNames(StringRef, SMLoc) {
412     return parseSectionSwitch("__TEXT", "__cstring",
413                               MachO::S_CSTRING_LITERALS);
414   }
415 
416   bool parseSectionDirectiveObjCSelectorStrs(StringRef, SMLoc) {
417     return parseSectionSwitch("__OBJC", "__selector_strs",
418                               MachO::S_CSTRING_LITERALS);
419   }
420 
421   bool parseSectionDirectiveTData(StringRef, SMLoc) {
422     return parseSectionSwitch("__DATA", "__thread_data",
423                               MachO::S_THREAD_LOCAL_REGULAR);
424   }
425 
426   bool parseSectionDirectiveText(StringRef, SMLoc) {
427     return parseSectionSwitch("__TEXT", "__text",
428                               MachO::S_ATTR_PURE_INSTRUCTIONS);
429   }
430 
431   bool parseSectionDirectiveTLV(StringRef, SMLoc) {
432     return parseSectionSwitch("__DATA", "__thread_vars",
433                               MachO::S_THREAD_LOCAL_VARIABLES);
434   }
435 
436   bool parseSectionDirectiveIdent(StringRef, SMLoc) {
437     // Darwin silently ignores the .ident directive.
438     getParser().eatToEndOfStatement();
439     return false;
440   }
441 
442   bool parseSectionDirectiveThreadInitFunc(StringRef, SMLoc) {
443     return parseSectionSwitch("__DATA", "__thread_init",
444                          MachO::S_THREAD_LOCAL_INIT_FUNCTION_POINTERS);
445   }
446 
447   bool parseWatchOSVersionMin(StringRef Directive, SMLoc Loc) {
448     return parseVersionMin(Directive, Loc, MCVM_WatchOSVersionMin);
449   }
450   bool parseTvOSVersionMin(StringRef Directive, SMLoc Loc) {
451     return parseVersionMin(Directive, Loc, MCVM_TvOSVersionMin);
452   }
453   bool parseIOSVersionMin(StringRef Directive, SMLoc Loc) {
454     return parseVersionMin(Directive, Loc, MCVM_IOSVersionMin);
455   }
456   bool parseMacOSXVersionMin(StringRef Directive, SMLoc Loc) {
457     return parseVersionMin(Directive, Loc, MCVM_OSXVersionMin);
458   }
459 
460   bool parseBuildVersion(StringRef Directive, SMLoc Loc);
461   bool parseVersionMin(StringRef Directive, SMLoc Loc, MCVersionMinType Type);
462   bool parseMajorMinorVersionComponent(unsigned *Major, unsigned *Minor,
463                                        const char *VersionName);
464   bool parseOptionalTrailingVersionComponent(unsigned *Component,
465                                              const char *ComponentName);
466   bool parseVersion(unsigned *Major, unsigned *Minor, unsigned *Update);
467   bool parseSDKVersion(VersionTuple &SDKVersion);
468   void checkVersion(StringRef Directive, StringRef Arg, SMLoc Loc,
469                     Triple::OSType ExpectedOS);
470 };
471 
472 } // end anonymous namespace
473 
474 bool DarwinAsmParser::parseSectionSwitch(StringRef Segment, StringRef Section,
475                                          unsigned TAA, unsigned Align,
476                                          unsigned StubSize) {
477   if (getLexer().isNot(AsmToken::EndOfStatement))
478     return TokError("unexpected token in section switching directive");
479   Lex();
480 
481   // FIXME: Arch specific.
482   bool isText = TAA & MachO::S_ATTR_PURE_INSTRUCTIONS;
483   getStreamer().SwitchSection(getContext().getMachOSection(
484       Segment, Section, TAA, StubSize,
485       isText ? SectionKind::getText() : SectionKind::getData()));
486 
487   // Set the implicit alignment, if any.
488   //
489   // FIXME: This isn't really what 'as' does; I think it just uses the implicit
490   // alignment on the section (e.g., if one manually inserts bytes into the
491   // section, then just issuing the section switch directive will not realign
492   // the section. However, this is arguably more reasonable behavior, and there
493   // is no good reason for someone to intentionally emit incorrectly sized
494   // values into the implicitly aligned sections.
495   if (Align)
496     getStreamer().EmitValueToAlignment(Align);
497 
498   return false;
499 }
500 
501 /// parseDirectiveAltEntry
502 ///  ::= .alt_entry identifier
503 bool DarwinAsmParser::parseDirectiveAltEntry(StringRef, SMLoc) {
504   StringRef Name;
505   if (getParser().parseIdentifier(Name))
506     return TokError("expected identifier in directive");
507 
508   // Look up symbol.
509   MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
510 
511   if (Sym->isDefined())
512     return TokError(".alt_entry must preceed symbol definition");
513 
514   if (!getStreamer().EmitSymbolAttribute(Sym, MCSA_AltEntry))
515     return TokError("unable to emit symbol attribute");
516 
517   Lex();
518   return false;
519 }
520 
521 /// parseDirectiveDesc
522 ///  ::= .desc identifier , expression
523 bool DarwinAsmParser::parseDirectiveDesc(StringRef, SMLoc) {
524   StringRef Name;
525   if (getParser().parseIdentifier(Name))
526     return TokError("expected identifier in directive");
527 
528   // Handle the identifier as the key symbol.
529   MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
530 
531   if (getLexer().isNot(AsmToken::Comma))
532     return TokError("unexpected token in '.desc' directive");
533   Lex();
534 
535   int64_t DescValue;
536   if (getParser().parseAbsoluteExpression(DescValue))
537     return true;
538 
539   if (getLexer().isNot(AsmToken::EndOfStatement))
540     return TokError("unexpected token in '.desc' directive");
541 
542   Lex();
543 
544   // Set the n_desc field of this Symbol to this DescValue
545   getStreamer().EmitSymbolDesc(Sym, DescValue);
546 
547   return false;
548 }
549 
550 /// parseDirectiveIndirectSymbol
551 ///  ::= .indirect_symbol identifier
552 bool DarwinAsmParser::parseDirectiveIndirectSymbol(StringRef, SMLoc Loc) {
553   const MCSectionMachO *Current = static_cast<const MCSectionMachO *>(
554       getStreamer().getCurrentSectionOnly());
555   MachO::SectionType SectionType = Current->getType();
556   if (SectionType != MachO::S_NON_LAZY_SYMBOL_POINTERS &&
557       SectionType != MachO::S_LAZY_SYMBOL_POINTERS &&
558       SectionType != MachO::S_THREAD_LOCAL_VARIABLE_POINTERS &&
559       SectionType != MachO::S_SYMBOL_STUBS)
560     return Error(Loc, "indirect symbol not in a symbol pointer or stub "
561                       "section");
562 
563   StringRef Name;
564   if (getParser().parseIdentifier(Name))
565     return TokError("expected identifier in .indirect_symbol directive");
566 
567   MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
568 
569   // Assembler local symbols don't make any sense here. Complain loudly.
570   if (Sym->isTemporary())
571     return TokError("non-local symbol required in directive");
572 
573   if (!getStreamer().EmitSymbolAttribute(Sym, MCSA_IndirectSymbol))
574     return TokError("unable to emit indirect symbol attribute for: " + Name);
575 
576   if (getLexer().isNot(AsmToken::EndOfStatement))
577     return TokError("unexpected token in '.indirect_symbol' directive");
578 
579   Lex();
580 
581   return false;
582 }
583 
584 /// parseDirectiveDumpOrLoad
585 ///  ::= ( .dump | .load ) "filename"
586 bool DarwinAsmParser::parseDirectiveDumpOrLoad(StringRef Directive,
587                                                SMLoc IDLoc) {
588   bool IsDump = Directive == ".dump";
589   if (getLexer().isNot(AsmToken::String))
590     return TokError("expected string in '.dump' or '.load' directive");
591 
592   Lex();
593 
594   if (getLexer().isNot(AsmToken::EndOfStatement))
595     return TokError("unexpected token in '.dump' or '.load' directive");
596 
597   Lex();
598 
599   // FIXME: If/when .dump and .load are implemented they will be done in the
600   // the assembly parser and not have any need for an MCStreamer API.
601   if (IsDump)
602     return Warning(IDLoc, "ignoring directive .dump for now");
603   else
604     return Warning(IDLoc, "ignoring directive .load for now");
605 }
606 
607 /// ParseDirectiveLinkerOption
608 ///  ::= .linker_option "string" ( , "string" )*
609 bool DarwinAsmParser::parseDirectiveLinkerOption(StringRef IDVal, SMLoc) {
610   SmallVector<std::string, 4> Args;
611   while (true) {
612     if (getLexer().isNot(AsmToken::String))
613       return TokError("expected string in '" + Twine(IDVal) + "' directive");
614 
615     std::string Data;
616     if (getParser().parseEscapedString(Data))
617       return true;
618 
619     Args.push_back(Data);
620 
621     if (getLexer().is(AsmToken::EndOfStatement))
622       break;
623 
624     if (getLexer().isNot(AsmToken::Comma))
625       return TokError("unexpected token in '" + Twine(IDVal) + "' directive");
626     Lex();
627   }
628 
629   getStreamer().EmitLinkerOptions(Args);
630   return false;
631 }
632 
633 /// parseDirectiveLsym
634 ///  ::= .lsym identifier , expression
635 bool DarwinAsmParser::parseDirectiveLsym(StringRef, SMLoc) {
636   StringRef Name;
637   if (getParser().parseIdentifier(Name))
638     return TokError("expected identifier in directive");
639 
640   // Handle the identifier as the key symbol.
641   MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
642 
643   if (getLexer().isNot(AsmToken::Comma))
644     return TokError("unexpected token in '.lsym' directive");
645   Lex();
646 
647   const MCExpr *Value;
648   if (getParser().parseExpression(Value))
649     return true;
650 
651   if (getLexer().isNot(AsmToken::EndOfStatement))
652     return TokError("unexpected token in '.lsym' directive");
653 
654   Lex();
655 
656   // We don't currently support this directive.
657   //
658   // FIXME: Diagnostic location!
659   (void) Sym;
660   return TokError("directive '.lsym' is unsupported");
661 }
662 
663 /// parseDirectiveSection:
664 ///   ::= .section identifier (',' identifier)*
665 bool DarwinAsmParser::parseDirectiveSection(StringRef, SMLoc) {
666   SMLoc Loc = getLexer().getLoc();
667 
668   StringRef SectionName;
669   if (getParser().parseIdentifier(SectionName))
670     return Error(Loc, "expected identifier after '.section' directive");
671 
672   // Verify there is a following comma.
673   if (!getLexer().is(AsmToken::Comma))
674     return TokError("unexpected token in '.section' directive");
675 
676   std::string SectionSpec = SectionName;
677   SectionSpec += ",";
678 
679   // Add all the tokens until the end of the line, ParseSectionSpecifier will
680   // handle this.
681   StringRef EOL = getLexer().LexUntilEndOfStatement();
682   SectionSpec.append(EOL.begin(), EOL.end());
683 
684   Lex();
685   if (getLexer().isNot(AsmToken::EndOfStatement))
686     return TokError("unexpected token in '.section' directive");
687   Lex();
688 
689   StringRef Segment, Section;
690   unsigned StubSize;
691   unsigned TAA;
692   bool TAAParsed;
693   std::string ErrorStr =
694     MCSectionMachO::ParseSectionSpecifier(SectionSpec, Segment, Section,
695                                           TAA, TAAParsed, StubSize);
696 
697   if (!ErrorStr.empty())
698     return Error(Loc, ErrorStr);
699 
700   // Issue a warning if the target is not powerpc and Section is a *coal* section.
701   Triple TT = getParser().getContext().getObjectFileInfo()->getTargetTriple();
702   Triple::ArchType ArchTy = TT.getArch();
703 
704   if (ArchTy != Triple::ppc && ArchTy != Triple::ppc64) {
705     StringRef NonCoalSection = StringSwitch<StringRef>(Section)
706                                    .Case("__textcoal_nt", "__text")
707                                    .Case("__const_coal", "__const")
708                                    .Case("__datacoal_nt", "__data")
709                                    .Default(Section);
710 
711     if (!Section.equals(NonCoalSection)) {
712       StringRef SectionVal(Loc.getPointer());
713       size_t B = SectionVal.find(',') + 1, E = SectionVal.find(',', B);
714       SMLoc BLoc = SMLoc::getFromPointer(SectionVal.data() + B);
715       SMLoc ELoc = SMLoc::getFromPointer(SectionVal.data() + E);
716       getParser().Warning(Loc, "section \"" + Section + "\" is deprecated",
717                           SMRange(BLoc, ELoc));
718       getParser().Note(Loc, "change section name to \"" + NonCoalSection +
719                        "\"", SMRange(BLoc, ELoc));
720     }
721   }
722 
723   // FIXME: Arch specific.
724   bool isText = Segment == "__TEXT";  // FIXME: Hack.
725   getStreamer().SwitchSection(getContext().getMachOSection(
726       Segment, Section, TAA, StubSize,
727       isText ? SectionKind::getText() : SectionKind::getData()));
728   return false;
729 }
730 
731 /// ParseDirectivePushSection:
732 ///   ::= .pushsection identifier (',' identifier)*
733 bool DarwinAsmParser::parseDirectivePushSection(StringRef S, SMLoc Loc) {
734   getStreamer().PushSection();
735 
736   if (parseDirectiveSection(S, Loc)) {
737     getStreamer().PopSection();
738     return true;
739   }
740 
741   return false;
742 }
743 
744 /// ParseDirectivePopSection:
745 ///   ::= .popsection
746 bool DarwinAsmParser::parseDirectivePopSection(StringRef, SMLoc) {
747   if (!getStreamer().PopSection())
748     return TokError(".popsection without corresponding .pushsection");
749   return false;
750 }
751 
752 /// ParseDirectivePrevious:
753 ///   ::= .previous
754 bool DarwinAsmParser::parseDirectivePrevious(StringRef DirName, SMLoc) {
755   MCSectionSubPair PreviousSection = getStreamer().getPreviousSection();
756   if (!PreviousSection.first)
757     return TokError(".previous without corresponding .section");
758   getStreamer().SwitchSection(PreviousSection.first, PreviousSection.second);
759   return false;
760 }
761 
762 /// ParseDirectiveSecureLogUnique
763 ///  ::= .secure_log_unique ... message ...
764 bool DarwinAsmParser::parseDirectiveSecureLogUnique(StringRef, SMLoc IDLoc) {
765   StringRef LogMessage = getParser().parseStringToEndOfStatement();
766   if (getLexer().isNot(AsmToken::EndOfStatement))
767     return TokError("unexpected token in '.secure_log_unique' directive");
768 
769   if (getContext().getSecureLogUsed())
770     return Error(IDLoc, ".secure_log_unique specified multiple times");
771 
772   // Get the secure log path.
773   const char *SecureLogFile = getContext().getSecureLogFile();
774   if (!SecureLogFile)
775     return Error(IDLoc, ".secure_log_unique used but AS_SECURE_LOG_FILE "
776                  "environment variable unset.");
777 
778   // Open the secure log file if we haven't already.
779   raw_fd_ostream *OS = getContext().getSecureLog();
780   if (!OS) {
781     std::error_code EC;
782     auto NewOS = llvm::make_unique<raw_fd_ostream>(
783         StringRef(SecureLogFile), EC, sys::fs::F_Append | sys::fs::F_Text);
784     if (EC)
785        return Error(IDLoc, Twine("can't open secure log file: ") +
786                                SecureLogFile + " (" + EC.message() + ")");
787     OS = NewOS.get();
788     getContext().setSecureLog(std::move(NewOS));
789   }
790 
791   // Write the message.
792   unsigned CurBuf = getSourceManager().FindBufferContainingLoc(IDLoc);
793   *OS << getSourceManager().getBufferInfo(CurBuf).Buffer->getBufferIdentifier()
794       << ":" << getSourceManager().FindLineNumber(IDLoc, CurBuf) << ":"
795       << LogMessage + "\n";
796 
797   getContext().setSecureLogUsed(true);
798 
799   return false;
800 }
801 
802 /// ParseDirectiveSecureLogReset
803 ///  ::= .secure_log_reset
804 bool DarwinAsmParser::parseDirectiveSecureLogReset(StringRef, SMLoc IDLoc) {
805   if (getLexer().isNot(AsmToken::EndOfStatement))
806     return TokError("unexpected token in '.secure_log_reset' directive");
807 
808   Lex();
809 
810   getContext().setSecureLogUsed(false);
811 
812   return false;
813 }
814 
815 /// parseDirectiveSubsectionsViaSymbols
816 ///  ::= .subsections_via_symbols
817 bool DarwinAsmParser::parseDirectiveSubsectionsViaSymbols(StringRef, SMLoc) {
818   if (getLexer().isNot(AsmToken::EndOfStatement))
819     return TokError("unexpected token in '.subsections_via_symbols' directive");
820 
821   Lex();
822 
823   getStreamer().EmitAssemblerFlag(MCAF_SubsectionsViaSymbols);
824 
825   return false;
826 }
827 
828 /// ParseDirectiveTBSS
829 ///  ::= .tbss identifier, size, align
830 bool DarwinAsmParser::parseDirectiveTBSS(StringRef, SMLoc) {
831   SMLoc IDLoc = getLexer().getLoc();
832   StringRef Name;
833   if (getParser().parseIdentifier(Name))
834     return TokError("expected identifier in directive");
835 
836   // Handle the identifier as the key symbol.
837   MCSymbol *Sym = getContext().getOrCreateSymbol(Name);
838 
839   if (getLexer().isNot(AsmToken::Comma))
840     return TokError("unexpected token in directive");
841   Lex();
842 
843   int64_t Size;
844   SMLoc SizeLoc = getLexer().getLoc();
845   if (getParser().parseAbsoluteExpression(Size))
846     return true;
847 
848   int64_t Pow2Alignment = 0;
849   SMLoc Pow2AlignmentLoc;
850   if (getLexer().is(AsmToken::Comma)) {
851     Lex();
852     Pow2AlignmentLoc = getLexer().getLoc();
853     if (getParser().parseAbsoluteExpression(Pow2Alignment))
854       return true;
855   }
856 
857   if (getLexer().isNot(AsmToken::EndOfStatement))
858     return TokError("unexpected token in '.tbss' directive");
859 
860   Lex();
861 
862   if (Size < 0)
863     return Error(SizeLoc, "invalid '.tbss' directive size, can't be less than"
864                  "zero");
865 
866   // FIXME: Diagnose overflow.
867   if (Pow2Alignment < 0)
868     return Error(Pow2AlignmentLoc, "invalid '.tbss' alignment, can't be less"
869                  "than zero");
870 
871   if (!Sym->isUndefined())
872     return Error(IDLoc, "invalid symbol redefinition");
873 
874   getStreamer().EmitTBSSSymbol(getContext().getMachOSection(
875                                  "__DATA", "__thread_bss",
876                                  MachO::S_THREAD_LOCAL_ZEROFILL,
877                                  0, SectionKind::getThreadBSS()),
878                                Sym, Size, 1 << Pow2Alignment);
879 
880   return false;
881 }
882 
883 /// ParseDirectiveZerofill
884 ///  ::= .zerofill segname , sectname [, identifier , size_expression [
885 ///      , align_expression ]]
886 bool DarwinAsmParser::parseDirectiveZerofill(StringRef, SMLoc) {
887   StringRef Segment;
888   if (getParser().parseIdentifier(Segment))
889     return TokError("expected segment name after '.zerofill' directive");
890 
891   if (getLexer().isNot(AsmToken::Comma))
892     return TokError("unexpected token in directive");
893   Lex();
894 
895   StringRef Section;
896   SMLoc SectionLoc = getLexer().getLoc();
897   if (getParser().parseIdentifier(Section))
898     return TokError("expected section name after comma in '.zerofill' "
899                     "directive");
900 
901   // If this is the end of the line all that was wanted was to create the
902   // the section but with no symbol.
903   if (getLexer().is(AsmToken::EndOfStatement)) {
904     // Create the zerofill section but no symbol
905     getStreamer().EmitZerofill(
906         getContext().getMachOSection(Segment, Section, MachO::S_ZEROFILL, 0,
907                                      SectionKind::getBSS()),
908         /*Symbol=*/nullptr, /*Size=*/0, /*ByteAlignment=*/0, SectionLoc);
909     return false;
910   }
911 
912   if (getLexer().isNot(AsmToken::Comma))
913     return TokError("unexpected token in directive");
914   Lex();
915 
916   SMLoc IDLoc = getLexer().getLoc();
917   StringRef IDStr;
918   if (getParser().parseIdentifier(IDStr))
919     return TokError("expected identifier in directive");
920 
921   // handle the identifier as the key symbol.
922   MCSymbol *Sym = getContext().getOrCreateSymbol(IDStr);
923 
924   if (getLexer().isNot(AsmToken::Comma))
925     return TokError("unexpected token in directive");
926   Lex();
927 
928   int64_t Size;
929   SMLoc SizeLoc = getLexer().getLoc();
930   if (getParser().parseAbsoluteExpression(Size))
931     return true;
932 
933   int64_t Pow2Alignment = 0;
934   SMLoc Pow2AlignmentLoc;
935   if (getLexer().is(AsmToken::Comma)) {
936     Lex();
937     Pow2AlignmentLoc = getLexer().getLoc();
938     if (getParser().parseAbsoluteExpression(Pow2Alignment))
939       return true;
940   }
941 
942   if (getLexer().isNot(AsmToken::EndOfStatement))
943     return TokError("unexpected token in '.zerofill' directive");
944 
945   Lex();
946 
947   if (Size < 0)
948     return Error(SizeLoc, "invalid '.zerofill' directive size, can't be less "
949                  "than zero");
950 
951   // NOTE: The alignment in the directive is a power of 2 value, the assembler
952   // may internally end up wanting an alignment in bytes.
953   // FIXME: Diagnose overflow.
954   if (Pow2Alignment < 0)
955     return Error(Pow2AlignmentLoc, "invalid '.zerofill' directive alignment, "
956                  "can't be less than zero");
957 
958   if (!Sym->isUndefined())
959     return Error(IDLoc, "invalid symbol redefinition");
960 
961   // Create the zerofill Symbol with Size and Pow2Alignment
962   //
963   // FIXME: Arch specific.
964   getStreamer().EmitZerofill(getContext().getMachOSection(
965                                Segment, Section, MachO::S_ZEROFILL,
966                                0, SectionKind::getBSS()),
967                              Sym, Size, 1 << Pow2Alignment, SectionLoc);
968 
969   return false;
970 }
971 
972 /// ParseDirectiveDataRegion
973 ///  ::= .data_region [ ( jt8 | jt16 | jt32 ) ]
974 bool DarwinAsmParser::parseDirectiveDataRegion(StringRef, SMLoc) {
975   if (getLexer().is(AsmToken::EndOfStatement)) {
976     Lex();
977     getStreamer().EmitDataRegion(MCDR_DataRegion);
978     return false;
979   }
980   StringRef RegionType;
981   SMLoc Loc = getParser().getTok().getLoc();
982   if (getParser().parseIdentifier(RegionType))
983     return TokError("expected region type after '.data_region' directive");
984   int Kind = StringSwitch<int>(RegionType)
985     .Case("jt8", MCDR_DataRegionJT8)
986     .Case("jt16", MCDR_DataRegionJT16)
987     .Case("jt32", MCDR_DataRegionJT32)
988     .Default(-1);
989   if (Kind == -1)
990     return Error(Loc, "unknown region type in '.data_region' directive");
991   Lex();
992 
993   getStreamer().EmitDataRegion((MCDataRegionType)Kind);
994   return false;
995 }
996 
997 /// ParseDirectiveDataRegionEnd
998 ///  ::= .end_data_region
999 bool DarwinAsmParser::parseDirectiveDataRegionEnd(StringRef, SMLoc) {
1000   if (getLexer().isNot(AsmToken::EndOfStatement))
1001     return TokError("unexpected token in '.end_data_region' directive");
1002 
1003   Lex();
1004   getStreamer().EmitDataRegion(MCDR_DataRegionEnd);
1005   return false;
1006 }
1007 
1008 static bool isSDKVersionToken(const AsmToken &Tok) {
1009   return Tok.is(AsmToken::Identifier) && Tok.getIdentifier() == "sdk_version";
1010 }
1011 
1012 /// parseMajorMinorVersionComponent ::= major, minor
1013 bool DarwinAsmParser::parseMajorMinorVersionComponent(unsigned *Major,
1014                                                       unsigned *Minor,
1015                                                       const char *VersionName) {
1016   // Get the major version number.
1017   if (getLexer().isNot(AsmToken::Integer))
1018     return TokError(Twine("invalid ") + VersionName +
1019                     " major version number, integer expected");
1020   int64_t MajorVal = getLexer().getTok().getIntVal();
1021   if (MajorVal > 65535 || MajorVal <= 0)
1022     return TokError(Twine("invalid ") + VersionName + " major version number");
1023   *Major = (unsigned)MajorVal;
1024   Lex();
1025   if (getLexer().isNot(AsmToken::Comma))
1026     return TokError(Twine(VersionName) +
1027                     " minor version number required, comma expected");
1028   Lex();
1029   // Get the minor version number.
1030   if (getLexer().isNot(AsmToken::Integer))
1031     return TokError(Twine("invalid ") + VersionName +
1032                     " minor version number, integer expected");
1033   int64_t MinorVal = getLexer().getTok().getIntVal();
1034   if (MinorVal > 255 || MinorVal < 0)
1035     return TokError(Twine("invalid ") + VersionName + " minor version number");
1036   *Minor = MinorVal;
1037   Lex();
1038   return false;
1039 }
1040 
1041 /// parseOptionalTrailingVersionComponent ::= , version_number
1042 bool DarwinAsmParser::parseOptionalTrailingVersionComponent(
1043     unsigned *Component, const char *ComponentName) {
1044   assert(getLexer().is(AsmToken::Comma) && "comma expected");
1045   Lex();
1046   if (getLexer().isNot(AsmToken::Integer))
1047     return TokError(Twine("invalid ") + ComponentName +
1048                     " version number, integer expected");
1049   int64_t Val = getLexer().getTok().getIntVal();
1050   if (Val > 255 || Val < 0)
1051     return TokError(Twine("invalid ") + ComponentName + " version number");
1052   *Component = Val;
1053   Lex();
1054   return false;
1055 }
1056 
1057 /// parseVersion ::= parseMajorMinorVersionComponent
1058 ///                      parseOptionalTrailingVersionComponent
1059 bool DarwinAsmParser::parseVersion(unsigned *Major, unsigned *Minor,
1060                                    unsigned *Update) {
1061   if (parseMajorMinorVersionComponent(Major, Minor, "OS"))
1062     return true;
1063 
1064   // Get the update level, if specified
1065   *Update = 0;
1066   if (getLexer().is(AsmToken::EndOfStatement) ||
1067       isSDKVersionToken(getLexer().getTok()))
1068     return false;
1069   if (getLexer().isNot(AsmToken::Comma))
1070     return TokError("invalid OS update specifier, comma expected");
1071   if (parseOptionalTrailingVersionComponent(Update, "OS update"))
1072     return true;
1073   return false;
1074 }
1075 
1076 bool DarwinAsmParser::parseSDKVersion(VersionTuple &SDKVersion) {
1077   assert(isSDKVersionToken(getLexer().getTok()) && "expected sdk_version");
1078   Lex();
1079   unsigned Major, Minor;
1080   if (parseMajorMinorVersionComponent(&Major, &Minor, "SDK"))
1081     return true;
1082   SDKVersion = VersionTuple(Major, Minor);
1083 
1084   // Get the subminor version, if specified.
1085   if (getLexer().is(AsmToken::Comma)) {
1086     unsigned Subminor;
1087     if (parseOptionalTrailingVersionComponent(&Subminor, "SDK subminor"))
1088       return true;
1089     SDKVersion = VersionTuple(Major, Minor, Subminor);
1090   }
1091   return false;
1092 }
1093 
1094 void DarwinAsmParser::checkVersion(StringRef Directive, StringRef Arg,
1095                                    SMLoc Loc, Triple::OSType ExpectedOS) {
1096   const Triple &Target = getContext().getObjectFileInfo()->getTargetTriple();
1097   if (Target.getOS() != ExpectedOS)
1098     Warning(Loc, Twine(Directive) +
1099             (Arg.empty() ? Twine() : Twine(' ') + Arg) +
1100             " used while targeting " + Target.getOSName());
1101 
1102   if (LastVersionDirective.isValid()) {
1103     Warning(Loc, "overriding previous version directive");
1104     Note(LastVersionDirective, "previous definition is here");
1105   }
1106   LastVersionDirective = Loc;
1107 }
1108 
1109 static Triple::OSType getOSTypeFromMCVM(MCVersionMinType Type) {
1110   switch (Type) {
1111   case MCVM_WatchOSVersionMin: return Triple::WatchOS;
1112   case MCVM_TvOSVersionMin:    return Triple::TvOS;
1113   case MCVM_IOSVersionMin:     return Triple::IOS;
1114   case MCVM_OSXVersionMin:     return Triple::MacOSX;
1115   }
1116   llvm_unreachable("Invalid mc version min type");
1117 }
1118 
1119 /// parseVersionMin
1120 ///   ::= .ios_version_min parseVersion parseSDKVersion
1121 ///   |   .macosx_version_min parseVersion parseSDKVersion
1122 ///   |   .tvos_version_min parseVersion parseSDKVersion
1123 ///   |   .watchos_version_min parseVersion parseSDKVersion
1124 bool DarwinAsmParser::parseVersionMin(StringRef Directive, SMLoc Loc,
1125                                       MCVersionMinType Type) {
1126   unsigned Major;
1127   unsigned Minor;
1128   unsigned Update;
1129   if (parseVersion(&Major, &Minor, &Update))
1130     return true;
1131 
1132   VersionTuple SDKVersion;
1133   if (isSDKVersionToken(getLexer().getTok()) && parseSDKVersion(SDKVersion))
1134     return true;
1135 
1136   if (parseToken(AsmToken::EndOfStatement))
1137     return addErrorSuffix(Twine(" in '") + Directive + "' directive");
1138 
1139   Triple::OSType ExpectedOS = getOSTypeFromMCVM(Type);
1140   checkVersion(Directive, StringRef(), Loc, ExpectedOS);
1141   getStreamer().EmitVersionMin(Type, Major, Minor, Update, SDKVersion);
1142   return false;
1143 }
1144 
1145 static Triple::OSType getOSTypeFromPlatform(MachO::PlatformType Type) {
1146   switch (Type) {
1147   case MachO::PLATFORM_MACOS:   return Triple::MacOSX;
1148   case MachO::PLATFORM_IOS:     return Triple::IOS;
1149   case MachO::PLATFORM_TVOS:    return Triple::TvOS;
1150   case MachO::PLATFORM_WATCHOS: return Triple::WatchOS;
1151   case MachO::PLATFORM_BRIDGEOS:         /* silence warning */ break;
1152   case MachO::PLATFORM_IOSSIMULATOR:     /* silence warning */ break;
1153   case MachO::PLATFORM_TVOSSIMULATOR:    /* silence warning */ break;
1154   case MachO::PLATFORM_WATCHOSSIMULATOR: /* silence warning */ break;
1155   }
1156   llvm_unreachable("Invalid mach-o platform type");
1157 }
1158 
1159 /// parseBuildVersion
1160 ///   ::= .build_version (macos|ios|tvos|watchos), parseVersion parseSDKVersion
1161 bool DarwinAsmParser::parseBuildVersion(StringRef Directive, SMLoc Loc) {
1162   StringRef PlatformName;
1163   SMLoc PlatformLoc = getTok().getLoc();
1164   if (getParser().parseIdentifier(PlatformName))
1165     return TokError("platform name expected");
1166 
1167   unsigned Platform = StringSwitch<unsigned>(PlatformName)
1168     .Case("macos", MachO::PLATFORM_MACOS)
1169     .Case("ios", MachO::PLATFORM_IOS)
1170     .Case("tvos", MachO::PLATFORM_TVOS)
1171     .Case("watchos", MachO::PLATFORM_WATCHOS)
1172     .Default(0);
1173   if (Platform == 0)
1174     return Error(PlatformLoc, "unknown platform name");
1175 
1176   if (getLexer().isNot(AsmToken::Comma))
1177     return TokError("version number required, comma expected");
1178   Lex();
1179 
1180   unsigned Major;
1181   unsigned Minor;
1182   unsigned Update;
1183   if (parseVersion(&Major, &Minor, &Update))
1184     return true;
1185 
1186   VersionTuple SDKVersion;
1187   if (isSDKVersionToken(getLexer().getTok()) && parseSDKVersion(SDKVersion))
1188     return true;
1189 
1190   if (parseToken(AsmToken::EndOfStatement))
1191     return addErrorSuffix(" in '.build_version' directive");
1192 
1193   Triple::OSType ExpectedOS
1194     = getOSTypeFromPlatform((MachO::PlatformType)Platform);
1195   checkVersion(Directive, PlatformName, Loc, ExpectedOS);
1196   getStreamer().EmitBuildVersion(Platform, Major, Minor, Update, SDKVersion);
1197   return false;
1198 }
1199 
1200 
1201 namespace llvm {
1202 
1203 MCAsmParserExtension *createDarwinAsmParser() {
1204   return new DarwinAsmParser;
1205 }
1206 
1207 } // end llvm namespace
1208