1 //===- ELFAsmParser.cpp - ELF 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/MC/MCParser/MCAsmParserExtension.h"
11 #include "llvm/ADT/StringSwitch.h"
12 #include "llvm/ADT/Twine.h"
13 #include "llvm/MC/MCAsmInfo.h"
14 #include "llvm/MC/MCContext.h"
15 #include "llvm/MC/MCExpr.h"
16 #include "llvm/MC/MCParser/MCAsmLexer.h"
17 #include "llvm/MC/MCSectionELF.h"
18 #include "llvm/MC/MCStreamer.h"
19 #include "llvm/MC/MCSymbol.h"
20 #include "llvm/Support/ELF.h"
21 using namespace llvm;
22 
23 namespace {
24 
25 class ELFAsmParser : public MCAsmParserExtension {
26   template<bool (ELFAsmParser::*HandlerMethod)(StringRef, SMLoc)>
addDirectiveHandler(StringRef Directive)27   void addDirectiveHandler(StringRef Directive) {
28     MCAsmParser::ExtensionDirectiveHandler Handler = std::make_pair(
29         this, HandleDirective<ELFAsmParser, HandlerMethod>);
30 
31     getParser().addDirectiveHandler(Directive, Handler);
32   }
33 
34   bool ParseSectionSwitch(StringRef Section, unsigned Type, unsigned Flags,
35                           SectionKind Kind);
36 
37 public:
ELFAsmParser()38   ELFAsmParser() { BracketExpressionsSupported = true; }
39 
Initialize(MCAsmParser & Parser)40   void Initialize(MCAsmParser &Parser) override {
41     // Call the base implementation.
42     this->MCAsmParserExtension::Initialize(Parser);
43 
44     addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveData>(".data");
45     addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveText>(".text");
46     addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveBSS>(".bss");
47     addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveRoData>(".rodata");
48     addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTData>(".tdata");
49     addDirectiveHandler<&ELFAsmParser::ParseSectionDirectiveTBSS>(".tbss");
50     addDirectiveHandler<
51       &ELFAsmParser::ParseSectionDirectiveDataRel>(".data.rel");
52     addDirectiveHandler<
53       &ELFAsmParser::ParseSectionDirectiveDataRelRo>(".data.rel.ro");
54     addDirectiveHandler<
55       &ELFAsmParser::ParseSectionDirectiveDataRelRoLocal>(".data.rel.ro.local");
56     addDirectiveHandler<
57       &ELFAsmParser::ParseSectionDirectiveEhFrame>(".eh_frame");
58     addDirectiveHandler<&ELFAsmParser::ParseDirectiveSection>(".section");
59     addDirectiveHandler<
60       &ELFAsmParser::ParseDirectivePushSection>(".pushsection");
61     addDirectiveHandler<&ELFAsmParser::ParseDirectivePopSection>(".popsection");
62     addDirectiveHandler<&ELFAsmParser::ParseDirectiveSize>(".size");
63     addDirectiveHandler<&ELFAsmParser::ParseDirectivePrevious>(".previous");
64     addDirectiveHandler<&ELFAsmParser::ParseDirectiveType>(".type");
65     addDirectiveHandler<&ELFAsmParser::ParseDirectiveIdent>(".ident");
66     addDirectiveHandler<&ELFAsmParser::ParseDirectiveSymver>(".symver");
67     addDirectiveHandler<&ELFAsmParser::ParseDirectiveVersion>(".version");
68     addDirectiveHandler<&ELFAsmParser::ParseDirectiveWeakref>(".weakref");
69     addDirectiveHandler<&ELFAsmParser::ParseDirectiveSymbolAttribute>(".weak");
70     addDirectiveHandler<&ELFAsmParser::ParseDirectiveSymbolAttribute>(".local");
71     addDirectiveHandler<
72       &ELFAsmParser::ParseDirectiveSymbolAttribute>(".protected");
73     addDirectiveHandler<
74       &ELFAsmParser::ParseDirectiveSymbolAttribute>(".internal");
75     addDirectiveHandler<
76       &ELFAsmParser::ParseDirectiveSymbolAttribute>(".hidden");
77     addDirectiveHandler<&ELFAsmParser::ParseDirectiveSubsection>(".subsection");
78   }
79 
80   // FIXME: Part of this logic is duplicated in the MCELFStreamer. What is
81   // the best way for us to get access to it?
ParseSectionDirectiveData(StringRef,SMLoc)82   bool ParseSectionDirectiveData(StringRef, SMLoc) {
83     return ParseSectionSwitch(".data", ELF::SHT_PROGBITS,
84                               ELF::SHF_WRITE |ELF::SHF_ALLOC,
85                               SectionKind::getDataRel());
86   }
ParseSectionDirectiveText(StringRef,SMLoc)87   bool ParseSectionDirectiveText(StringRef, SMLoc) {
88     return ParseSectionSwitch(".text", ELF::SHT_PROGBITS,
89                               ELF::SHF_EXECINSTR |
90                               ELF::SHF_ALLOC, SectionKind::getText());
91   }
ParseSectionDirectiveBSS(StringRef,SMLoc)92   bool ParseSectionDirectiveBSS(StringRef, SMLoc) {
93     return ParseSectionSwitch(".bss", ELF::SHT_NOBITS,
94                               ELF::SHF_WRITE |
95                               ELF::SHF_ALLOC, SectionKind::getBSS());
96   }
ParseSectionDirectiveRoData(StringRef,SMLoc)97   bool ParseSectionDirectiveRoData(StringRef, SMLoc) {
98     return ParseSectionSwitch(".rodata", ELF::SHT_PROGBITS,
99                               ELF::SHF_ALLOC,
100                               SectionKind::getReadOnly());
101   }
ParseSectionDirectiveTData(StringRef,SMLoc)102   bool ParseSectionDirectiveTData(StringRef, SMLoc) {
103     return ParseSectionSwitch(".tdata", ELF::SHT_PROGBITS,
104                               ELF::SHF_ALLOC |
105                               ELF::SHF_TLS | ELF::SHF_WRITE,
106                               SectionKind::getThreadData());
107   }
ParseSectionDirectiveTBSS(StringRef,SMLoc)108   bool ParseSectionDirectiveTBSS(StringRef, SMLoc) {
109     return ParseSectionSwitch(".tbss", ELF::SHT_NOBITS,
110                               ELF::SHF_ALLOC |
111                               ELF::SHF_TLS | ELF::SHF_WRITE,
112                               SectionKind::getThreadBSS());
113   }
ParseSectionDirectiveDataRel(StringRef,SMLoc)114   bool ParseSectionDirectiveDataRel(StringRef, SMLoc) {
115     return ParseSectionSwitch(".data.rel", ELF::SHT_PROGBITS,
116                               ELF::SHF_ALLOC |
117                               ELF::SHF_WRITE,
118                               SectionKind::getDataRel());
119   }
ParseSectionDirectiveDataRelRo(StringRef,SMLoc)120   bool ParseSectionDirectiveDataRelRo(StringRef, SMLoc) {
121     return ParseSectionSwitch(".data.rel.ro", ELF::SHT_PROGBITS,
122                               ELF::SHF_ALLOC |
123                               ELF::SHF_WRITE,
124                               SectionKind::getReadOnlyWithRel());
125   }
ParseSectionDirectiveDataRelRoLocal(StringRef,SMLoc)126   bool ParseSectionDirectiveDataRelRoLocal(StringRef, SMLoc) {
127     return ParseSectionSwitch(".data.rel.ro.local", ELF::SHT_PROGBITS,
128                               ELF::SHF_ALLOC |
129                               ELF::SHF_WRITE,
130                               SectionKind::getReadOnlyWithRelLocal());
131   }
ParseSectionDirectiveEhFrame(StringRef,SMLoc)132   bool ParseSectionDirectiveEhFrame(StringRef, SMLoc) {
133     return ParseSectionSwitch(".eh_frame", ELF::SHT_PROGBITS,
134                               ELF::SHF_ALLOC |
135                               ELF::SHF_WRITE,
136                               SectionKind::getDataRel());
137   }
138   bool ParseDirectivePushSection(StringRef, SMLoc);
139   bool ParseDirectivePopSection(StringRef, SMLoc);
140   bool ParseDirectiveSection(StringRef, SMLoc);
141   bool ParseDirectiveSize(StringRef, SMLoc);
142   bool ParseDirectivePrevious(StringRef, SMLoc);
143   bool ParseDirectiveType(StringRef, SMLoc);
144   bool ParseDirectiveIdent(StringRef, SMLoc);
145   bool ParseDirectiveSymver(StringRef, SMLoc);
146   bool ParseDirectiveVersion(StringRef, SMLoc);
147   bool ParseDirectiveWeakref(StringRef, SMLoc);
148   bool ParseDirectiveSymbolAttribute(StringRef, SMLoc);
149   bool ParseDirectiveSubsection(StringRef, SMLoc);
150 
151 private:
152   bool ParseSectionName(StringRef &SectionName);
153   bool ParseSectionArguments(bool IsPush, SMLoc loc);
154   unsigned parseSunStyleSectionFlags();
155 };
156 
157 }
158 
159 /// ParseDirectiveSymbolAttribute
160 ///  ::= { ".local", ".weak", ... } [ identifier ( , identifier )* ]
ParseDirectiveSymbolAttribute(StringRef Directive,SMLoc)161 bool ELFAsmParser::ParseDirectiveSymbolAttribute(StringRef Directive, SMLoc) {
162   MCSymbolAttr Attr = StringSwitch<MCSymbolAttr>(Directive)
163     .Case(".weak", MCSA_Weak)
164     .Case(".local", MCSA_Local)
165     .Case(".hidden", MCSA_Hidden)
166     .Case(".internal", MCSA_Internal)
167     .Case(".protected", MCSA_Protected)
168     .Default(MCSA_Invalid);
169   assert(Attr != MCSA_Invalid && "unexpected symbol attribute directive!");
170   if (getLexer().isNot(AsmToken::EndOfStatement)) {
171     for (;;) {
172       StringRef Name;
173 
174       if (getParser().parseIdentifier(Name))
175         return TokError("expected identifier in directive");
176 
177       MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
178 
179       getStreamer().EmitSymbolAttribute(Sym, Attr);
180 
181       if (getLexer().is(AsmToken::EndOfStatement))
182         break;
183 
184       if (getLexer().isNot(AsmToken::Comma))
185         return TokError("unexpected token in directive");
186       Lex();
187     }
188   }
189 
190   Lex();
191   return false;
192 }
193 
ParseSectionSwitch(StringRef Section,unsigned Type,unsigned Flags,SectionKind Kind)194 bool ELFAsmParser::ParseSectionSwitch(StringRef Section, unsigned Type,
195                                       unsigned Flags, SectionKind Kind) {
196   const MCExpr *Subsection = nullptr;
197   if (getLexer().isNot(AsmToken::EndOfStatement)) {
198     if (getParser().parseExpression(Subsection))
199       return true;
200   }
201 
202   getStreamer().SwitchSection(getContext().getELFSection(Section, Type, Flags),
203                               Subsection);
204 
205   return false;
206 }
207 
ParseDirectiveSize(StringRef,SMLoc)208 bool ELFAsmParser::ParseDirectiveSize(StringRef, SMLoc) {
209   StringRef Name;
210   if (getParser().parseIdentifier(Name))
211     return TokError("expected identifier in directive");
212   MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
213 
214   if (getLexer().isNot(AsmToken::Comma))
215     return TokError("unexpected token in directive");
216   Lex();
217 
218   const MCExpr *Expr;
219   if (getParser().parseExpression(Expr))
220     return true;
221 
222   if (getLexer().isNot(AsmToken::EndOfStatement))
223     return TokError("unexpected token in directive");
224 
225   getStreamer().EmitELFSize(Sym, Expr);
226   return false;
227 }
228 
ParseSectionName(StringRef & SectionName)229 bool ELFAsmParser::ParseSectionName(StringRef &SectionName) {
230   // A section name can contain -, so we cannot just use
231   // parseIdentifier.
232   SMLoc FirstLoc = getLexer().getLoc();
233   unsigned Size = 0;
234 
235   if (getLexer().is(AsmToken::String)) {
236     SectionName = getTok().getIdentifier();
237     Lex();
238     return false;
239   }
240 
241   for (;;) {
242     unsigned CurSize;
243 
244     SMLoc PrevLoc = getLexer().getLoc();
245     if (getLexer().is(AsmToken::Minus)) {
246       CurSize = 1;
247       Lex(); // Consume the "-".
248     } else if (getLexer().is(AsmToken::String)) {
249       CurSize = getTok().getIdentifier().size() + 2;
250       Lex();
251     } else if (getLexer().is(AsmToken::Identifier)) {
252       CurSize = getTok().getIdentifier().size();
253       Lex();
254     } else {
255       break;
256     }
257 
258     Size += CurSize;
259     SectionName = StringRef(FirstLoc.getPointer(), Size);
260 
261     // Make sure the following token is adjacent.
262     if (PrevLoc.getPointer() + CurSize != getTok().getLoc().getPointer())
263       break;
264   }
265   if (Size == 0)
266     return true;
267 
268   return false;
269 }
270 
parseSectionFlags(StringRef flagsStr,bool * UseLastGroup)271 static unsigned parseSectionFlags(StringRef flagsStr, bool *UseLastGroup) {
272   unsigned flags = 0;
273 
274   for (unsigned i = 0; i < flagsStr.size(); i++) {
275     switch (flagsStr[i]) {
276     case 'a':
277       flags |= ELF::SHF_ALLOC;
278       break;
279     case 'e':
280       flags |= ELF::SHF_EXCLUDE;
281       break;
282     case 'x':
283       flags |= ELF::SHF_EXECINSTR;
284       break;
285     case 'w':
286       flags |= ELF::SHF_WRITE;
287       break;
288     case 'M':
289       flags |= ELF::SHF_MERGE;
290       break;
291     case 'S':
292       flags |= ELF::SHF_STRINGS;
293       break;
294     case 'T':
295       flags |= ELF::SHF_TLS;
296       break;
297     case 'c':
298       flags |= ELF::XCORE_SHF_CP_SECTION;
299       break;
300     case 'd':
301       flags |= ELF::XCORE_SHF_DP_SECTION;
302       break;
303     case 'G':
304       flags |= ELF::SHF_GROUP;
305       break;
306     case '?':
307       *UseLastGroup = true;
308       break;
309     default:
310       return -1U;
311     }
312   }
313 
314   return flags;
315 }
316 
parseSunStyleSectionFlags()317 unsigned ELFAsmParser::parseSunStyleSectionFlags() {
318   unsigned flags = 0;
319   while (getLexer().is(AsmToken::Hash)) {
320     Lex(); // Eat the #.
321 
322     if (!getLexer().is(AsmToken::Identifier))
323       return -1U;
324 
325     StringRef flagId = getTok().getIdentifier();
326     if (flagId == "alloc")
327       flags |= ELF::SHF_ALLOC;
328     else if (flagId == "execinstr")
329       flags |= ELF::SHF_EXECINSTR;
330     else if (flagId == "write")
331       flags |= ELF::SHF_WRITE;
332     else if (flagId == "tls")
333       flags |= ELF::SHF_TLS;
334     else
335       return -1U;
336 
337     Lex(); // Eat the flag.
338 
339     if (!getLexer().is(AsmToken::Comma))
340         break;
341     Lex(); // Eat the comma.
342   }
343   return flags;
344 }
345 
346 
ParseDirectivePushSection(StringRef s,SMLoc loc)347 bool ELFAsmParser::ParseDirectivePushSection(StringRef s, SMLoc loc) {
348   getStreamer().PushSection();
349 
350   if (ParseSectionArguments(/*IsPush=*/true, loc)) {
351     getStreamer().PopSection();
352     return true;
353   }
354 
355   return false;
356 }
357 
ParseDirectivePopSection(StringRef,SMLoc)358 bool ELFAsmParser::ParseDirectivePopSection(StringRef, SMLoc) {
359   if (!getStreamer().PopSection())
360     return TokError(".popsection without corresponding .pushsection");
361   return false;
362 }
363 
364 // FIXME: This is a work in progress.
ParseDirectiveSection(StringRef,SMLoc loc)365 bool ELFAsmParser::ParseDirectiveSection(StringRef, SMLoc loc) {
366   return ParseSectionArguments(/*IsPush=*/false, loc);
367 }
368 
ParseSectionArguments(bool IsPush,SMLoc loc)369 bool ELFAsmParser::ParseSectionArguments(bool IsPush, SMLoc loc) {
370   StringRef SectionName;
371 
372   if (ParseSectionName(SectionName))
373     return TokError("expected identifier in directive");
374 
375   StringRef TypeName;
376   int64_t Size = 0;
377   StringRef GroupName;
378   unsigned Flags = 0;
379   const MCExpr *Subsection = nullptr;
380   bool UseLastGroup = false;
381   StringRef UniqueStr;
382   int64_t UniqueID = ~0;
383 
384   // Set the defaults first.
385   if (SectionName == ".fini" || SectionName == ".init" ||
386       SectionName == ".rodata")
387     Flags |= ELF::SHF_ALLOC;
388   if (SectionName == ".fini" || SectionName == ".init")
389     Flags |= ELF::SHF_EXECINSTR;
390 
391   if (getLexer().is(AsmToken::Comma)) {
392     Lex();
393 
394     if (IsPush && getLexer().isNot(AsmToken::String)) {
395       if (getParser().parseExpression(Subsection))
396         return true;
397       if (getLexer().isNot(AsmToken::Comma))
398         goto EndStmt;
399       Lex();
400     }
401 
402     unsigned extraFlags;
403 
404     if (getLexer().isNot(AsmToken::String)) {
405       if (!getContext().getAsmInfo()->usesSunStyleELFSectionSwitchSyntax()
406           || getLexer().isNot(AsmToken::Hash))
407         return TokError("expected string in directive");
408       extraFlags = parseSunStyleSectionFlags();
409     } else {
410       StringRef FlagsStr = getTok().getStringContents();
411       Lex();
412       extraFlags = parseSectionFlags(FlagsStr, &UseLastGroup);
413     }
414 
415     if (extraFlags == -1U)
416       return TokError("unknown flag");
417     Flags |= extraFlags;
418 
419     bool Mergeable = Flags & ELF::SHF_MERGE;
420     bool Group = Flags & ELF::SHF_GROUP;
421     if (Group && UseLastGroup)
422       return TokError("Section cannot specifiy a group name while also acting "
423                       "as a member of the last group");
424 
425     if (getLexer().isNot(AsmToken::Comma)) {
426       if (Mergeable)
427         return TokError("Mergeable section must specify the type");
428       if (Group)
429         return TokError("Group section must specify the type");
430     } else {
431       Lex();
432       if (getLexer().is(AsmToken::At) || getLexer().is(AsmToken::Percent) ||
433           getLexer().is(AsmToken::String)) {
434         if (!getLexer().is(AsmToken::String))
435           Lex();
436       } else
437         return TokError("expected '@<type>', '%<type>' or \"<type>\"");
438 
439       if (getParser().parseIdentifier(TypeName))
440         return TokError("expected identifier in directive");
441 
442       if (Mergeable) {
443         if (getLexer().isNot(AsmToken::Comma))
444           return TokError("expected the entry size");
445         Lex();
446         if (getParser().parseAbsoluteExpression(Size))
447           return true;
448         if (Size <= 0)
449           return TokError("entry size must be positive");
450       }
451 
452       if (Group) {
453         if (getLexer().isNot(AsmToken::Comma))
454           return TokError("expected group name");
455         Lex();
456         if (getParser().parseIdentifier(GroupName))
457           return true;
458         if (getLexer().is(AsmToken::Comma)) {
459           Lex();
460           StringRef Linkage;
461           if (getParser().parseIdentifier(Linkage))
462             return true;
463           if (Linkage != "comdat")
464             return TokError("Linkage must be 'comdat'");
465         }
466       }
467       if (getLexer().is(AsmToken::Comma)) {
468         Lex();
469         if (getParser().parseIdentifier(UniqueStr))
470           return TokError("expected identifier in directive");
471         if (UniqueStr != "unique")
472           return TokError("expected 'unique'");
473         if (getLexer().isNot(AsmToken::Comma))
474           return TokError("expected commma");
475         Lex();
476         if (getParser().parseAbsoluteExpression(UniqueID))
477           return true;
478         if (UniqueID < 0)
479           return TokError("unique id must be positive");
480         if (!isUInt<32>(UniqueID) || UniqueID == ~0U)
481           return TokError("unique id is too large");
482       }
483     }
484   }
485 
486 EndStmt:
487   if (getLexer().isNot(AsmToken::EndOfStatement))
488     return TokError("unexpected token in directive");
489 
490   unsigned Type = ELF::SHT_PROGBITS;
491 
492   if (TypeName.empty()) {
493     if (SectionName.startswith(".note"))
494       Type = ELF::SHT_NOTE;
495     else if (SectionName == ".init_array")
496       Type = ELF::SHT_INIT_ARRAY;
497     else if (SectionName == ".fini_array")
498       Type = ELF::SHT_FINI_ARRAY;
499     else if (SectionName == ".preinit_array")
500       Type = ELF::SHT_PREINIT_ARRAY;
501   } else {
502     if (TypeName == "init_array")
503       Type = ELF::SHT_INIT_ARRAY;
504     else if (TypeName == "fini_array")
505       Type = ELF::SHT_FINI_ARRAY;
506     else if (TypeName == "preinit_array")
507       Type = ELF::SHT_PREINIT_ARRAY;
508     else if (TypeName == "nobits")
509       Type = ELF::SHT_NOBITS;
510     else if (TypeName == "progbits")
511       Type = ELF::SHT_PROGBITS;
512     else if (TypeName == "note")
513       Type = ELF::SHT_NOTE;
514     else if (TypeName == "unwind")
515       Type = ELF::SHT_X86_64_UNWIND;
516     else
517       return TokError("unknown section type");
518   }
519 
520   if (UseLastGroup) {
521     MCSectionSubPair CurrentSection = getStreamer().getCurrentSection();
522     if (const MCSectionELF *Section =
523             cast_or_null<MCSectionELF>(CurrentSection.first))
524       if (const MCSymbol *Group = Section->getGroup()) {
525         GroupName = Group->getName();
526         Flags |= ELF::SHF_GROUP;
527       }
528   }
529 
530   const MCSection *ELFSection = getContext().getELFSection(
531       SectionName, Type, Flags, Size, GroupName, UniqueID);
532   getStreamer().SwitchSection(ELFSection, Subsection);
533 
534   if (getContext().getGenDwarfForAssembly()) {
535     auto &Sections = getContext().getGenDwarfSectionSyms();
536     auto InsertResult = Sections.insert(
537         std::make_pair(ELFSection, std::make_pair(nullptr, nullptr)));
538     if (InsertResult.second) {
539       if (getContext().getDwarfVersion() <= 2)
540         Warning(loc, "DWARF2 only supports one section per compilation unit");
541 
542       MCSymbol *SectionStartSymbol = getContext().CreateTempSymbol();
543       getStreamer().EmitLabel(SectionStartSymbol);
544       InsertResult.first->second.first = SectionStartSymbol;
545     }
546   }
547 
548   return false;
549 }
550 
ParseDirectivePrevious(StringRef DirName,SMLoc)551 bool ELFAsmParser::ParseDirectivePrevious(StringRef DirName, SMLoc) {
552   MCSectionSubPair PreviousSection = getStreamer().getPreviousSection();
553   if (PreviousSection.first == nullptr)
554       return TokError(".previous without corresponding .section");
555   getStreamer().SwitchSection(PreviousSection.first, PreviousSection.second);
556 
557   return false;
558 }
559 
MCAttrForString(StringRef Type)560 static MCSymbolAttr MCAttrForString(StringRef Type) {
561   return StringSwitch<MCSymbolAttr>(Type)
562           .Cases("STT_FUNC", "function", MCSA_ELF_TypeFunction)
563           .Cases("STT_OBJECT", "object", MCSA_ELF_TypeObject)
564           .Cases("STT_TLS", "tls_object", MCSA_ELF_TypeTLS)
565           .Cases("STT_COMMON", "common", MCSA_ELF_TypeCommon)
566           .Cases("STT_NOTYPE", "notype", MCSA_ELF_TypeNoType)
567           .Cases("STT_GNU_IFUNC", "gnu_indirect_function",
568                  MCSA_ELF_TypeIndFunction)
569           .Case("gnu_unique_object", MCSA_ELF_TypeGnuUniqueObject)
570           .Default(MCSA_Invalid);
571 }
572 
573 /// ParseDirectiveELFType
574 ///  ::= .type identifier , STT_<TYPE_IN_UPPER_CASE>
575 ///  ::= .type identifier , #attribute
576 ///  ::= .type identifier , @attribute
577 ///  ::= .type identifier , %attribute
578 ///  ::= .type identifier , "attribute"
ParseDirectiveType(StringRef,SMLoc)579 bool ELFAsmParser::ParseDirectiveType(StringRef, SMLoc) {
580   StringRef Name;
581   if (getParser().parseIdentifier(Name))
582     return TokError("expected identifier in directive");
583 
584   // Handle the identifier as the key symbol.
585   MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
586 
587   // NOTE the comma is optional in all cases.  It is only documented as being
588   // optional in the first case, however, GAS will silently treat the comma as
589   // optional in all cases.  Furthermore, although the documentation states that
590   // the first form only accepts STT_<TYPE_IN_UPPER_CASE>, in reality, GAS
591   // accepts both the upper case name as well as the lower case aliases.
592   if (getLexer().is(AsmToken::Comma))
593     Lex();
594 
595   if (getLexer().isNot(AsmToken::Identifier) &&
596       getLexer().isNot(AsmToken::Hash) && getLexer().isNot(AsmToken::At) &&
597       getLexer().isNot(AsmToken::Percent) && getLexer().isNot(AsmToken::String))
598     return TokError("expected STT_<TYPE_IN_UPPER_CASE>, '#<type>', '@<type>', "
599                     "'%<type>' or \"<type>\"");
600 
601   if (getLexer().isNot(AsmToken::String) &&
602       getLexer().isNot(AsmToken::Identifier))
603     Lex();
604 
605   SMLoc TypeLoc = getLexer().getLoc();
606 
607   StringRef Type;
608   if (getParser().parseIdentifier(Type))
609     return TokError("expected symbol type in directive");
610 
611   MCSymbolAttr Attr = MCAttrForString(Type);
612   if (Attr == MCSA_Invalid)
613     return Error(TypeLoc, "unsupported attribute in '.type' directive");
614 
615   if (getLexer().isNot(AsmToken::EndOfStatement))
616     return TokError("unexpected token in '.type' directive");
617   Lex();
618 
619   getStreamer().EmitSymbolAttribute(Sym, Attr);
620 
621   return false;
622 }
623 
624 /// ParseDirectiveIdent
625 ///  ::= .ident string
ParseDirectiveIdent(StringRef,SMLoc)626 bool ELFAsmParser::ParseDirectiveIdent(StringRef, SMLoc) {
627   if (getLexer().isNot(AsmToken::String))
628     return TokError("unexpected token in '.ident' directive");
629 
630   StringRef Data = getTok().getIdentifier();
631 
632   Lex();
633 
634   getStreamer().EmitIdent(Data);
635   return false;
636 }
637 
638 /// ParseDirectiveSymver
639 ///  ::= .symver foo, bar2@zed
ParseDirectiveSymver(StringRef,SMLoc)640 bool ELFAsmParser::ParseDirectiveSymver(StringRef, SMLoc) {
641   StringRef Name;
642   if (getParser().parseIdentifier(Name))
643     return TokError("expected identifier in directive");
644 
645   if (getLexer().isNot(AsmToken::Comma))
646     return TokError("expected a comma");
647 
648   // ARM assembly uses @ for a comment...
649   // except when parsing the second parameter of the .symver directive.
650   // Force the next symbol to allow @ in the identifier, which is
651   // required for this directive and then reset it to its initial state.
652   const bool AllowAtInIdentifier = getLexer().getAllowAtInIdentifier();
653   getLexer().setAllowAtInIdentifier(true);
654   Lex();
655   getLexer().setAllowAtInIdentifier(AllowAtInIdentifier);
656 
657   StringRef AliasName;
658   if (getParser().parseIdentifier(AliasName))
659     return TokError("expected identifier in directive");
660 
661   if (AliasName.find('@') == StringRef::npos)
662     return TokError("expected a '@' in the name");
663 
664   MCSymbol *Alias = getContext().GetOrCreateSymbol(AliasName);
665   MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
666   const MCExpr *Value = MCSymbolRefExpr::Create(Sym, getContext());
667 
668   getStreamer().EmitAssignment(Alias, Value);
669   return false;
670 }
671 
672 /// ParseDirectiveVersion
673 ///  ::= .version string
ParseDirectiveVersion(StringRef,SMLoc)674 bool ELFAsmParser::ParseDirectiveVersion(StringRef, SMLoc) {
675   if (getLexer().isNot(AsmToken::String))
676     return TokError("unexpected token in '.version' directive");
677 
678   StringRef Data = getTok().getIdentifier();
679 
680   Lex();
681 
682   const MCSection *Note = getContext().getELFSection(".note", ELF::SHT_NOTE, 0);
683 
684   getStreamer().PushSection();
685   getStreamer().SwitchSection(Note);
686   getStreamer().EmitIntValue(Data.size()+1, 4); // namesz.
687   getStreamer().EmitIntValue(0, 4);             // descsz = 0 (no description).
688   getStreamer().EmitIntValue(1, 4);             // type = NT_VERSION.
689   getStreamer().EmitBytes(Data);                // name.
690   getStreamer().EmitIntValue(0, 1);             // terminate the string.
691   getStreamer().EmitValueToAlignment(4);        // ensure 4 byte alignment.
692   getStreamer().PopSection();
693   return false;
694 }
695 
696 /// ParseDirectiveWeakref
697 ///  ::= .weakref foo, bar
ParseDirectiveWeakref(StringRef,SMLoc)698 bool ELFAsmParser::ParseDirectiveWeakref(StringRef, SMLoc) {
699   // FIXME: Share code with the other alias building directives.
700 
701   StringRef AliasName;
702   if (getParser().parseIdentifier(AliasName))
703     return TokError("expected identifier in directive");
704 
705   if (getLexer().isNot(AsmToken::Comma))
706     return TokError("expected a comma");
707 
708   Lex();
709 
710   StringRef Name;
711   if (getParser().parseIdentifier(Name))
712     return TokError("expected identifier in directive");
713 
714   MCSymbol *Alias = getContext().GetOrCreateSymbol(AliasName);
715 
716   MCSymbol *Sym = getContext().GetOrCreateSymbol(Name);
717 
718   getStreamer().EmitWeakReference(Alias, Sym);
719   return false;
720 }
721 
ParseDirectiveSubsection(StringRef,SMLoc)722 bool ELFAsmParser::ParseDirectiveSubsection(StringRef, SMLoc) {
723   const MCExpr *Subsection = nullptr;
724   if (getLexer().isNot(AsmToken::EndOfStatement)) {
725     if (getParser().parseExpression(Subsection))
726      return true;
727   }
728 
729   if (getLexer().isNot(AsmToken::EndOfStatement))
730     return TokError("unexpected token in directive");
731 
732   getStreamer().SubSection(Subsection);
733   return false;
734 }
735 
736 namespace llvm {
737 
createELFAsmParser()738 MCAsmParserExtension *createELFAsmParser() {
739   return new ELFAsmParser;
740 }
741 
742 }
743