• Home
  • Line#
  • Scopes#
  • Navigate#
  • Raw
  • Download
1 //===--- ParseTemplate.cpp - Template Parsing -----------------------------===//
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 //  This file implements parsing of C++ templates.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #include "clang/Parse/Parser.h"
15 #include "RAIIObjectsForParser.h"
16 #include "clang/AST/ASTConsumer.h"
17 #include "clang/AST/ASTContext.h"
18 #include "clang/AST/DeclTemplate.h"
19 #include "clang/Parse/ParseDiagnostic.h"
20 #include "clang/Sema/DeclSpec.h"
21 #include "clang/Sema/ParsedTemplate.h"
22 #include "clang/Sema/Scope.h"
23 using namespace clang;
24 
25 /// \brief Parse a template declaration, explicit instantiation, or
26 /// explicit specialization.
27 Decl *
ParseDeclarationStartingWithTemplate(unsigned Context,SourceLocation & DeclEnd,AccessSpecifier AS,AttributeList * AccessAttrs)28 Parser::ParseDeclarationStartingWithTemplate(unsigned Context,
29                                              SourceLocation &DeclEnd,
30                                              AccessSpecifier AS,
31                                              AttributeList *AccessAttrs) {
32   ObjCDeclContextSwitch ObjCDC(*this);
33 
34   if (Tok.is(tok::kw_template) && NextToken().isNot(tok::less)) {
35     return ParseExplicitInstantiation(Context,
36                                       SourceLocation(), ConsumeToken(),
37                                       DeclEnd, AS);
38   }
39   return ParseTemplateDeclarationOrSpecialization(Context, DeclEnd, AS,
40                                                   AccessAttrs);
41 }
42 
43 
44 
45 /// \brief Parse a template declaration or an explicit specialization.
46 ///
47 /// Template declarations include one or more template parameter lists
48 /// and either the function or class template declaration. Explicit
49 /// specializations contain one or more 'template < >' prefixes
50 /// followed by a (possibly templated) declaration. Since the
51 /// syntactic form of both features is nearly identical, we parse all
52 /// of the template headers together and let semantic analysis sort
53 /// the declarations from the explicit specializations.
54 ///
55 ///       template-declaration: [C++ temp]
56 ///         'export'[opt] 'template' '<' template-parameter-list '>' declaration
57 ///
58 ///       explicit-specialization: [ C++ temp.expl.spec]
59 ///         'template' '<' '>' declaration
60 Decl *
ParseTemplateDeclarationOrSpecialization(unsigned Context,SourceLocation & DeclEnd,AccessSpecifier AS,AttributeList * AccessAttrs)61 Parser::ParseTemplateDeclarationOrSpecialization(unsigned Context,
62                                                  SourceLocation &DeclEnd,
63                                                  AccessSpecifier AS,
64                                                  AttributeList *AccessAttrs) {
65   assert(Tok.isOneOf(tok::kw_export, tok::kw_template) &&
66          "Token does not start a template declaration.");
67 
68   // Enter template-parameter scope.
69   ParseScope TemplateParmScope(this, Scope::TemplateParamScope);
70 
71   // Tell the action that names should be checked in the context of
72   // the declaration to come.
73   ParsingDeclRAIIObject
74     ParsingTemplateParams(*this, ParsingDeclRAIIObject::NoParent);
75 
76   // Parse multiple levels of template headers within this template
77   // parameter scope, e.g.,
78   //
79   //   template<typename T>
80   //     template<typename U>
81   //       class A<T>::B { ... };
82   //
83   // We parse multiple levels non-recursively so that we can build a
84   // single data structure containing all of the template parameter
85   // lists to easily differentiate between the case above and:
86   //
87   //   template<typename T>
88   //   class A {
89   //     template<typename U> class B;
90   //   };
91   //
92   // In the first case, the action for declaring A<T>::B receives
93   // both template parameter lists. In the second case, the action for
94   // defining A<T>::B receives just the inner template parameter list
95   // (and retrieves the outer template parameter list from its
96   // context).
97   bool isSpecialization = true;
98   bool LastParamListWasEmpty = false;
99   TemplateParameterLists ParamLists;
100   TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth);
101 
102   do {
103     // Consume the 'export', if any.
104     SourceLocation ExportLoc;
105     TryConsumeToken(tok::kw_export, ExportLoc);
106 
107     // Consume the 'template', which should be here.
108     SourceLocation TemplateLoc;
109     if (!TryConsumeToken(tok::kw_template, TemplateLoc)) {
110       Diag(Tok.getLocation(), diag::err_expected_template);
111       return nullptr;
112     }
113 
114     // Parse the '<' template-parameter-list '>'
115     SourceLocation LAngleLoc, RAngleLoc;
116     SmallVector<Decl*, 4> TemplateParams;
117     if (ParseTemplateParameters(CurTemplateDepthTracker.getDepth(),
118                                 TemplateParams, LAngleLoc, RAngleLoc)) {
119       // Skip until the semi-colon or a '}'.
120       SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch);
121       TryConsumeToken(tok::semi);
122       return nullptr;
123     }
124 
125     ExprResult OptionalRequiresClauseConstraintER;
126     if (!TemplateParams.empty()) {
127       isSpecialization = false;
128       ++CurTemplateDepthTracker;
129 
130       if (TryConsumeToken(tok::kw_requires)) {
131         OptionalRequiresClauseConstraintER =
132             Actions.CorrectDelayedTyposInExpr(ParseConstraintExpression());
133         if (!OptionalRequiresClauseConstraintER.isUsable()) {
134           // Skip until the semi-colon or a '}'.
135           SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch);
136           TryConsumeToken(tok::semi);
137           return nullptr;
138         }
139       }
140     } else {
141       LastParamListWasEmpty = true;
142     }
143 
144     ParamLists.push_back(Actions.ActOnTemplateParameterList(
145         CurTemplateDepthTracker.getDepth(), ExportLoc, TemplateLoc, LAngleLoc,
146         TemplateParams, RAngleLoc, OptionalRequiresClauseConstraintER.get()));
147   } while (Tok.isOneOf(tok::kw_export, tok::kw_template));
148 
149   unsigned NewFlags = getCurScope()->getFlags() & ~Scope::TemplateParamScope;
150   ParseScopeFlags TemplateScopeFlags(this, NewFlags, isSpecialization);
151 
152   // Parse the actual template declaration.
153   return ParseSingleDeclarationAfterTemplate(Context,
154                                              ParsedTemplateInfo(&ParamLists,
155                                                              isSpecialization,
156                                                          LastParamListWasEmpty),
157                                              ParsingTemplateParams,
158                                              DeclEnd, AS, AccessAttrs);
159 }
160 
161 /// \brief Parse a single declaration that declares a template,
162 /// template specialization, or explicit instantiation of a template.
163 ///
164 /// \param DeclEnd will receive the source location of the last token
165 /// within this declaration.
166 ///
167 /// \param AS the access specifier associated with this
168 /// declaration. Will be AS_none for namespace-scope declarations.
169 ///
170 /// \returns the new declaration.
171 Decl *
ParseSingleDeclarationAfterTemplate(unsigned Context,const ParsedTemplateInfo & TemplateInfo,ParsingDeclRAIIObject & DiagsFromTParams,SourceLocation & DeclEnd,AccessSpecifier AS,AttributeList * AccessAttrs)172 Parser::ParseSingleDeclarationAfterTemplate(
173                                        unsigned Context,
174                                        const ParsedTemplateInfo &TemplateInfo,
175                                        ParsingDeclRAIIObject &DiagsFromTParams,
176                                        SourceLocation &DeclEnd,
177                                        AccessSpecifier AS,
178                                        AttributeList *AccessAttrs) {
179   assert(TemplateInfo.Kind != ParsedTemplateInfo::NonTemplate &&
180          "Template information required");
181 
182   if (Tok.is(tok::kw_static_assert)) {
183     // A static_assert declaration may not be templated.
184     Diag(Tok.getLocation(), diag::err_templated_invalid_declaration)
185       << TemplateInfo.getSourceRange();
186     // Parse the static_assert declaration to improve error recovery.
187     return ParseStaticAssertDeclaration(DeclEnd);
188   }
189 
190   if (Context == Declarator::MemberContext) {
191     // We are parsing a member template.
192     ParseCXXClassMemberDeclaration(AS, AccessAttrs, TemplateInfo,
193                                    &DiagsFromTParams);
194     return nullptr;
195   }
196 
197   ParsedAttributesWithRange prefixAttrs(AttrFactory);
198   MaybeParseCXX11Attributes(prefixAttrs);
199 
200   if (Tok.is(tok::kw_using))
201     return ParseUsingDirectiveOrDeclaration(Context, TemplateInfo, DeclEnd,
202                                             prefixAttrs);
203 
204   // Parse the declaration specifiers, stealing any diagnostics from
205   // the template parameters.
206   ParsingDeclSpec DS(*this, &DiagsFromTParams);
207 
208   ParseDeclarationSpecifiers(DS, TemplateInfo, AS,
209                              getDeclSpecContextFromDeclaratorContext(Context));
210 
211   if (Tok.is(tok::semi)) {
212     ProhibitAttributes(prefixAttrs);
213     DeclEnd = ConsumeToken();
214     RecordDecl *AnonRecord = nullptr;
215     Decl *Decl = Actions.ParsedFreeStandingDeclSpec(
216         getCurScope(), AS, DS,
217         TemplateInfo.TemplateParams ? *TemplateInfo.TemplateParams
218                                     : MultiTemplateParamsArg(),
219         TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation,
220         AnonRecord);
221     assert(!AnonRecord &&
222            "Anonymous unions/structs should not be valid with template");
223     DS.complete(Decl);
224     return Decl;
225   }
226 
227   // Move the attributes from the prefix into the DS.
228   if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation)
229     ProhibitAttributes(prefixAttrs);
230   else
231     DS.takeAttributesFrom(prefixAttrs);
232 
233   // Parse the declarator.
234   ParsingDeclarator DeclaratorInfo(*this, DS, (Declarator::TheContext)Context);
235   ParseDeclarator(DeclaratorInfo);
236   // Error parsing the declarator?
237   if (!DeclaratorInfo.hasName()) {
238     // If so, skip until the semi-colon or a }.
239     SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch);
240     if (Tok.is(tok::semi))
241       ConsumeToken();
242     return nullptr;
243   }
244 
245   LateParsedAttrList LateParsedAttrs(true);
246   if (DeclaratorInfo.isFunctionDeclarator())
247     MaybeParseGNUAttributes(DeclaratorInfo, &LateParsedAttrs);
248 
249   if (DeclaratorInfo.isFunctionDeclarator() &&
250       isStartOfFunctionDefinition(DeclaratorInfo)) {
251 
252     // Function definitions are only allowed at file scope and in C++ classes.
253     // The C++ inline method definition case is handled elsewhere, so we only
254     // need to handle the file scope definition case.
255     if (Context != Declarator::FileContext) {
256       Diag(Tok, diag::err_function_definition_not_allowed);
257       SkipMalformedDecl();
258       return nullptr;
259     }
260 
261     if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef) {
262       // Recover by ignoring the 'typedef'. This was probably supposed to be
263       // the 'typename' keyword, which we should have already suggested adding
264       // if it's appropriate.
265       Diag(DS.getStorageClassSpecLoc(), diag::err_function_declared_typedef)
266         << FixItHint::CreateRemoval(DS.getStorageClassSpecLoc());
267       DS.ClearStorageClassSpecs();
268     }
269 
270     if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation) {
271       if (DeclaratorInfo.getName().getKind() != UnqualifiedId::IK_TemplateId) {
272         // If the declarator-id is not a template-id, issue a diagnostic and
273         // recover by ignoring the 'template' keyword.
274         Diag(Tok, diag::err_template_defn_explicit_instantiation) << 0;
275         return ParseFunctionDefinition(DeclaratorInfo, ParsedTemplateInfo(),
276                                        &LateParsedAttrs);
277       } else {
278         SourceLocation LAngleLoc
279           = PP.getLocForEndOfToken(TemplateInfo.TemplateLoc);
280         Diag(DeclaratorInfo.getIdentifierLoc(),
281              diag::err_explicit_instantiation_with_definition)
282             << SourceRange(TemplateInfo.TemplateLoc)
283             << FixItHint::CreateInsertion(LAngleLoc, "<>");
284 
285         // Recover as if it were an explicit specialization.
286         TemplateParameterLists FakedParamLists;
287         FakedParamLists.push_back(Actions.ActOnTemplateParameterList(
288             0, SourceLocation(), TemplateInfo.TemplateLoc, LAngleLoc, None,
289             LAngleLoc, nullptr));
290 
291         return ParseFunctionDefinition(
292             DeclaratorInfo, ParsedTemplateInfo(&FakedParamLists,
293                                                /*isSpecialization=*/true,
294                                                /*LastParamListWasEmpty=*/true),
295             &LateParsedAttrs);
296       }
297     }
298     return ParseFunctionDefinition(DeclaratorInfo, TemplateInfo,
299                                    &LateParsedAttrs);
300   }
301 
302   // Parse this declaration.
303   Decl *ThisDecl = ParseDeclarationAfterDeclarator(DeclaratorInfo,
304                                                    TemplateInfo);
305 
306   if (Tok.is(tok::comma)) {
307     Diag(Tok, diag::err_multiple_template_declarators)
308       << (int)TemplateInfo.Kind;
309     SkipUntil(tok::semi);
310     return ThisDecl;
311   }
312 
313   // Eat the semi colon after the declaration.
314   ExpectAndConsumeSemi(diag::err_expected_semi_declaration);
315   if (LateParsedAttrs.size() > 0)
316     ParseLexedAttributeList(LateParsedAttrs, ThisDecl, true, false);
317   DeclaratorInfo.complete(ThisDecl);
318   return ThisDecl;
319 }
320 
321 /// ParseTemplateParameters - Parses a template-parameter-list enclosed in
322 /// angle brackets. Depth is the depth of this template-parameter-list, which
323 /// is the number of template headers directly enclosing this template header.
324 /// TemplateParams is the current list of template parameters we're building.
325 /// The template parameter we parse will be added to this list. LAngleLoc and
326 /// RAngleLoc will receive the positions of the '<' and '>', respectively,
327 /// that enclose this template parameter list.
328 ///
329 /// \returns true if an error occurred, false otherwise.
ParseTemplateParameters(unsigned Depth,SmallVectorImpl<Decl * > & TemplateParams,SourceLocation & LAngleLoc,SourceLocation & RAngleLoc)330 bool Parser::ParseTemplateParameters(unsigned Depth,
331                                SmallVectorImpl<Decl*> &TemplateParams,
332                                      SourceLocation &LAngleLoc,
333                                      SourceLocation &RAngleLoc) {
334   // Get the template parameter list.
335   if (!TryConsumeToken(tok::less, LAngleLoc)) {
336     Diag(Tok.getLocation(), diag::err_expected_less_after) << "template";
337     return true;
338   }
339 
340   // Try to parse the template parameter list.
341   bool Failed = false;
342   if (!Tok.is(tok::greater) && !Tok.is(tok::greatergreater))
343     Failed = ParseTemplateParameterList(Depth, TemplateParams);
344 
345   if (Tok.is(tok::greatergreater)) {
346     // No diagnostic required here: a template-parameter-list can only be
347     // followed by a declaration or, for a template template parameter, the
348     // 'class' keyword. Therefore, the second '>' will be diagnosed later.
349     // This matters for elegant diagnosis of:
350     //   template<template<typename>> struct S;
351     Tok.setKind(tok::greater);
352     RAngleLoc = Tok.getLocation();
353     Tok.setLocation(Tok.getLocation().getLocWithOffset(1));
354   } else if (!TryConsumeToken(tok::greater, RAngleLoc) && Failed) {
355     Diag(Tok.getLocation(), diag::err_expected) << tok::greater;
356     return true;
357   }
358   return false;
359 }
360 
361 /// ParseTemplateParameterList - Parse a template parameter list. If
362 /// the parsing fails badly (i.e., closing bracket was left out), this
363 /// will try to put the token stream in a reasonable position (closing
364 /// a statement, etc.) and return false.
365 ///
366 ///       template-parameter-list:    [C++ temp]
367 ///         template-parameter
368 ///         template-parameter-list ',' template-parameter
369 bool
ParseTemplateParameterList(unsigned Depth,SmallVectorImpl<Decl * > & TemplateParams)370 Parser::ParseTemplateParameterList(unsigned Depth,
371                              SmallVectorImpl<Decl*> &TemplateParams) {
372   while (1) {
373     if (Decl *TmpParam
374           = ParseTemplateParameter(Depth, TemplateParams.size())) {
375       TemplateParams.push_back(TmpParam);
376     } else {
377       // If we failed to parse a template parameter, skip until we find
378       // a comma or closing brace.
379       SkipUntil(tok::comma, tok::greater, tok::greatergreater,
380                 StopAtSemi | StopBeforeMatch);
381     }
382 
383     // Did we find a comma or the end of the template parameter list?
384     if (Tok.is(tok::comma)) {
385       ConsumeToken();
386     } else if (Tok.isOneOf(tok::greater, tok::greatergreater)) {
387       // Don't consume this... that's done by template parser.
388       break;
389     } else {
390       // Somebody probably forgot to close the template. Skip ahead and
391       // try to get out of the expression. This error is currently
392       // subsumed by whatever goes on in ParseTemplateParameter.
393       Diag(Tok.getLocation(), diag::err_expected_comma_greater);
394       SkipUntil(tok::comma, tok::greater, tok::greatergreater,
395                 StopAtSemi | StopBeforeMatch);
396       return false;
397     }
398   }
399   return true;
400 }
401 
402 /// \brief Determine whether the parser is at the start of a template
403 /// type parameter.
isStartOfTemplateTypeParameter()404 bool Parser::isStartOfTemplateTypeParameter() {
405   if (Tok.is(tok::kw_class)) {
406     // "class" may be the start of an elaborated-type-specifier or a
407     // type-parameter. Per C++ [temp.param]p3, we prefer the type-parameter.
408     switch (NextToken().getKind()) {
409     case tok::equal:
410     case tok::comma:
411     case tok::greater:
412     case tok::greatergreater:
413     case tok::ellipsis:
414       return true;
415 
416     case tok::identifier:
417       // This may be either a type-parameter or an elaborated-type-specifier.
418       // We have to look further.
419       break;
420 
421     default:
422       return false;
423     }
424 
425     switch (GetLookAheadToken(2).getKind()) {
426     case tok::equal:
427     case tok::comma:
428     case tok::greater:
429     case tok::greatergreater:
430       return true;
431 
432     default:
433       return false;
434     }
435   }
436 
437   if (Tok.isNot(tok::kw_typename))
438     return false;
439 
440   // C++ [temp.param]p2:
441   //   There is no semantic difference between class and typename in a
442   //   template-parameter. typename followed by an unqualified-id
443   //   names a template type parameter. typename followed by a
444   //   qualified-id denotes the type in a non-type
445   //   parameter-declaration.
446   Token Next = NextToken();
447 
448   // If we have an identifier, skip over it.
449   if (Next.getKind() == tok::identifier)
450     Next = GetLookAheadToken(2);
451 
452   switch (Next.getKind()) {
453   case tok::equal:
454   case tok::comma:
455   case tok::greater:
456   case tok::greatergreater:
457   case tok::ellipsis:
458     return true;
459 
460   default:
461     return false;
462   }
463 }
464 
465 /// ParseTemplateParameter - Parse a template-parameter (C++ [temp.param]).
466 ///
467 ///       template-parameter: [C++ temp.param]
468 ///         type-parameter
469 ///         parameter-declaration
470 ///
471 ///       type-parameter: (see below)
472 ///         'class' ...[opt] identifier[opt]
473 ///         'class' identifier[opt] '=' type-id
474 ///         'typename' ...[opt] identifier[opt]
475 ///         'typename' identifier[opt] '=' type-id
476 ///         'template' '<' template-parameter-list '>'
477 ///               'class' ...[opt] identifier[opt]
478 ///         'template' '<' template-parameter-list '>' 'class' identifier[opt]
479 ///               = id-expression
ParseTemplateParameter(unsigned Depth,unsigned Position)480 Decl *Parser::ParseTemplateParameter(unsigned Depth, unsigned Position) {
481   if (isStartOfTemplateTypeParameter())
482     return ParseTypeParameter(Depth, Position);
483 
484   if (Tok.is(tok::kw_template))
485     return ParseTemplateTemplateParameter(Depth, Position);
486 
487   // If it's none of the above, then it must be a parameter declaration.
488   // NOTE: This will pick up errors in the closure of the template parameter
489   // list (e.g., template < ; Check here to implement >> style closures.
490   return ParseNonTypeTemplateParameter(Depth, Position);
491 }
492 
493 /// ParseTypeParameter - Parse a template type parameter (C++ [temp.param]).
494 /// Other kinds of template parameters are parsed in
495 /// ParseTemplateTemplateParameter and ParseNonTypeTemplateParameter.
496 ///
497 ///       type-parameter:     [C++ temp.param]
498 ///         'class' ...[opt][C++0x] identifier[opt]
499 ///         'class' identifier[opt] '=' type-id
500 ///         'typename' ...[opt][C++0x] identifier[opt]
501 ///         'typename' identifier[opt] '=' type-id
ParseTypeParameter(unsigned Depth,unsigned Position)502 Decl *Parser::ParseTypeParameter(unsigned Depth, unsigned Position) {
503   assert(Tok.isOneOf(tok::kw_class, tok::kw_typename) &&
504          "A type-parameter starts with 'class' or 'typename'");
505 
506   // Consume the 'class' or 'typename' keyword.
507   bool TypenameKeyword = Tok.is(tok::kw_typename);
508   SourceLocation KeyLoc = ConsumeToken();
509 
510   // Grab the ellipsis (if given).
511   SourceLocation EllipsisLoc;
512   if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) {
513     Diag(EllipsisLoc,
514          getLangOpts().CPlusPlus11
515            ? diag::warn_cxx98_compat_variadic_templates
516            : diag::ext_variadic_templates);
517   }
518 
519   // Grab the template parameter name (if given)
520   SourceLocation NameLoc;
521   IdentifierInfo *ParamName = nullptr;
522   if (Tok.is(tok::identifier)) {
523     ParamName = Tok.getIdentifierInfo();
524     NameLoc = ConsumeToken();
525   } else if (Tok.isOneOf(tok::equal, tok::comma, tok::greater,
526                          tok::greatergreater)) {
527     // Unnamed template parameter. Don't have to do anything here, just
528     // don't consume this token.
529   } else {
530     Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
531     return nullptr;
532   }
533 
534   // Recover from misplaced ellipsis.
535   bool AlreadyHasEllipsis = EllipsisLoc.isValid();
536   if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
537     DiagnoseMisplacedEllipsis(EllipsisLoc, NameLoc, AlreadyHasEllipsis, true);
538 
539   // Grab a default argument (if available).
540   // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
541   // we introduce the type parameter into the local scope.
542   SourceLocation EqualLoc;
543   ParsedType DefaultArg;
544   if (TryConsumeToken(tok::equal, EqualLoc))
545     DefaultArg = ParseTypeName(/*Range=*/nullptr,
546                                Declarator::TemplateTypeArgContext).get();
547 
548   return Actions.ActOnTypeParameter(getCurScope(), TypenameKeyword, EllipsisLoc,
549                                     KeyLoc, ParamName, NameLoc, Depth, Position,
550                                     EqualLoc, DefaultArg);
551 }
552 
553 /// ParseTemplateTemplateParameter - Handle the parsing of template
554 /// template parameters.
555 ///
556 ///       type-parameter:    [C++ temp.param]
557 ///         'template' '<' template-parameter-list '>' type-parameter-key
558 ///                  ...[opt] identifier[opt]
559 ///         'template' '<' template-parameter-list '>' type-parameter-key
560 ///                  identifier[opt] = id-expression
561 ///       type-parameter-key:
562 ///         'class'
563 ///         'typename'       [C++1z]
564 Decl *
ParseTemplateTemplateParameter(unsigned Depth,unsigned Position)565 Parser::ParseTemplateTemplateParameter(unsigned Depth, unsigned Position) {
566   assert(Tok.is(tok::kw_template) && "Expected 'template' keyword");
567 
568   // Handle the template <...> part.
569   SourceLocation TemplateLoc = ConsumeToken();
570   SmallVector<Decl*,8> TemplateParams;
571   SourceLocation LAngleLoc, RAngleLoc;
572   {
573     ParseScope TemplateParmScope(this, Scope::TemplateParamScope);
574     if (ParseTemplateParameters(Depth + 1, TemplateParams, LAngleLoc,
575                                RAngleLoc)) {
576       return nullptr;
577     }
578   }
579 
580   // Provide an ExtWarn if the C++1z feature of using 'typename' here is used.
581   // Generate a meaningful error if the user forgot to put class before the
582   // identifier, comma, or greater. Provide a fixit if the identifier, comma,
583   // or greater appear immediately or after 'struct'. In the latter case,
584   // replace the keyword with 'class'.
585   if (!TryConsumeToken(tok::kw_class)) {
586     bool Replace = Tok.isOneOf(tok::kw_typename, tok::kw_struct);
587     const Token &Next = Tok.is(tok::kw_struct) ? NextToken() : Tok;
588     if (Tok.is(tok::kw_typename)) {
589       Diag(Tok.getLocation(),
590            getLangOpts().CPlusPlus1z
591                ? diag::warn_cxx14_compat_template_template_param_typename
592                : diag::ext_template_template_param_typename)
593         << (!getLangOpts().CPlusPlus1z
594                 ? FixItHint::CreateReplacement(Tok.getLocation(), "class")
595                 : FixItHint());
596     } else if (Next.isOneOf(tok::identifier, tok::comma, tok::greater,
597                             tok::greatergreater, tok::ellipsis)) {
598       Diag(Tok.getLocation(), diag::err_class_on_template_template_param)
599         << (Replace ? FixItHint::CreateReplacement(Tok.getLocation(), "class")
600                     : FixItHint::CreateInsertion(Tok.getLocation(), "class "));
601     } else
602       Diag(Tok.getLocation(), diag::err_class_on_template_template_param);
603 
604     if (Replace)
605       ConsumeToken();
606   }
607 
608   // Parse the ellipsis, if given.
609   SourceLocation EllipsisLoc;
610   if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
611     Diag(EllipsisLoc,
612          getLangOpts().CPlusPlus11
613            ? diag::warn_cxx98_compat_variadic_templates
614            : diag::ext_variadic_templates);
615 
616   // Get the identifier, if given.
617   SourceLocation NameLoc;
618   IdentifierInfo *ParamName = nullptr;
619   if (Tok.is(tok::identifier)) {
620     ParamName = Tok.getIdentifierInfo();
621     NameLoc = ConsumeToken();
622   } else if (Tok.isOneOf(tok::equal, tok::comma, tok::greater,
623                          tok::greatergreater)) {
624     // Unnamed template parameter. Don't have to do anything here, just
625     // don't consume this token.
626   } else {
627     Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
628     return nullptr;
629   }
630 
631   // Recover from misplaced ellipsis.
632   bool AlreadyHasEllipsis = EllipsisLoc.isValid();
633   if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
634     DiagnoseMisplacedEllipsis(EllipsisLoc, NameLoc, AlreadyHasEllipsis, true);
635 
636   TemplateParameterList *ParamList =
637     Actions.ActOnTemplateParameterList(Depth, SourceLocation(),
638                                        TemplateLoc, LAngleLoc,
639                                        TemplateParams,
640                                        RAngleLoc, nullptr);
641 
642   // Grab a default argument (if available).
643   // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
644   // we introduce the template parameter into the local scope.
645   SourceLocation EqualLoc;
646   ParsedTemplateArgument DefaultArg;
647   if (TryConsumeToken(tok::equal, EqualLoc)) {
648     DefaultArg = ParseTemplateTemplateArgument();
649     if (DefaultArg.isInvalid()) {
650       Diag(Tok.getLocation(),
651            diag::err_default_template_template_parameter_not_template);
652       SkipUntil(tok::comma, tok::greater, tok::greatergreater,
653                 StopAtSemi | StopBeforeMatch);
654     }
655   }
656 
657   return Actions.ActOnTemplateTemplateParameter(getCurScope(), TemplateLoc,
658                                                 ParamList, EllipsisLoc,
659                                                 ParamName, NameLoc, Depth,
660                                                 Position, EqualLoc, DefaultArg);
661 }
662 
663 /// ParseNonTypeTemplateParameter - Handle the parsing of non-type
664 /// template parameters (e.g., in "template<int Size> class array;").
665 ///
666 ///       template-parameter:
667 ///         ...
668 ///         parameter-declaration
669 Decl *
ParseNonTypeTemplateParameter(unsigned Depth,unsigned Position)670 Parser::ParseNonTypeTemplateParameter(unsigned Depth, unsigned Position) {
671   // Parse the declaration-specifiers (i.e., the type).
672   // FIXME: The type should probably be restricted in some way... Not all
673   // declarators (parts of declarators?) are accepted for parameters.
674   DeclSpec DS(AttrFactory);
675   ParseDeclarationSpecifiers(DS);
676 
677   // Parse this as a typename.
678   Declarator ParamDecl(DS, Declarator::TemplateParamContext);
679   ParseDeclarator(ParamDecl);
680   if (DS.getTypeSpecType() == DeclSpec::TST_unspecified) {
681     Diag(Tok.getLocation(), diag::err_expected_template_parameter);
682     return nullptr;
683   }
684 
685   // Recover from misplaced ellipsis.
686   SourceLocation EllipsisLoc;
687   if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
688     DiagnoseMisplacedEllipsisInDeclarator(EllipsisLoc, ParamDecl);
689 
690   // If there is a default value, parse it.
691   // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
692   // we introduce the template parameter into the local scope.
693   SourceLocation EqualLoc;
694   ExprResult DefaultArg;
695   if (TryConsumeToken(tok::equal, EqualLoc)) {
696     // C++ [temp.param]p15:
697     //   When parsing a default template-argument for a non-type
698     //   template-parameter, the first non-nested > is taken as the
699     //   end of the template-parameter-list rather than a greater-than
700     //   operator.
701     GreaterThanIsOperatorScope G(GreaterThanIsOperator, false);
702     EnterExpressionEvaluationContext ConstantEvaluated(Actions,
703                                                        Sema::ConstantEvaluated);
704 
705     DefaultArg = Actions.CorrectDelayedTyposInExpr(ParseAssignmentExpression());
706     if (DefaultArg.isInvalid())
707       SkipUntil(tok::comma, tok::greater, StopAtSemi | StopBeforeMatch);
708   }
709 
710   // Create the parameter.
711   return Actions.ActOnNonTypeTemplateParameter(getCurScope(), ParamDecl,
712                                                Depth, Position, EqualLoc,
713                                                DefaultArg.get());
714 }
715 
DiagnoseMisplacedEllipsis(SourceLocation EllipsisLoc,SourceLocation CorrectLoc,bool AlreadyHasEllipsis,bool IdentifierHasName)716 void Parser::DiagnoseMisplacedEllipsis(SourceLocation EllipsisLoc,
717                                        SourceLocation CorrectLoc,
718                                        bool AlreadyHasEllipsis,
719                                        bool IdentifierHasName) {
720   FixItHint Insertion;
721   if (!AlreadyHasEllipsis)
722     Insertion = FixItHint::CreateInsertion(CorrectLoc, "...");
723   Diag(EllipsisLoc, diag::err_misplaced_ellipsis_in_declaration)
724       << FixItHint::CreateRemoval(EllipsisLoc) << Insertion
725       << !IdentifierHasName;
726 }
727 
DiagnoseMisplacedEllipsisInDeclarator(SourceLocation EllipsisLoc,Declarator & D)728 void Parser::DiagnoseMisplacedEllipsisInDeclarator(SourceLocation EllipsisLoc,
729                                                    Declarator &D) {
730   assert(EllipsisLoc.isValid());
731   bool AlreadyHasEllipsis = D.getEllipsisLoc().isValid();
732   if (!AlreadyHasEllipsis)
733     D.setEllipsisLoc(EllipsisLoc);
734   DiagnoseMisplacedEllipsis(EllipsisLoc, D.getIdentifierLoc(),
735                             AlreadyHasEllipsis, D.hasName());
736 }
737 
738 /// \brief Parses a '>' at the end of a template list.
739 ///
740 /// If this function encounters '>>', '>>>', '>=', or '>>=', it tries
741 /// to determine if these tokens were supposed to be a '>' followed by
742 /// '>', '>>', '>=', or '>='. It emits an appropriate diagnostic if necessary.
743 ///
744 /// \param RAngleLoc the location of the consumed '>'.
745 ///
746 /// \param ConsumeLastToken if true, the '>' is consumed.
747 ///
748 /// \param ObjCGenericList if true, this is the '>' closing an Objective-C
749 /// type parameter or type argument list, rather than a C++ template parameter
750 /// or argument list.
751 ///
752 /// \returns true, if current token does not start with '>', false otherwise.
ParseGreaterThanInTemplateList(SourceLocation & RAngleLoc,bool ConsumeLastToken,bool ObjCGenericList)753 bool Parser::ParseGreaterThanInTemplateList(SourceLocation &RAngleLoc,
754                                             bool ConsumeLastToken,
755                                             bool ObjCGenericList) {
756   // What will be left once we've consumed the '>'.
757   tok::TokenKind RemainingToken;
758   const char *ReplacementStr = "> >";
759 
760   switch (Tok.getKind()) {
761   default:
762     Diag(Tok.getLocation(), diag::err_expected) << tok::greater;
763     return true;
764 
765   case tok::greater:
766     // Determine the location of the '>' token. Only consume this token
767     // if the caller asked us to.
768     RAngleLoc = Tok.getLocation();
769     if (ConsumeLastToken)
770       ConsumeToken();
771     return false;
772 
773   case tok::greatergreater:
774     RemainingToken = tok::greater;
775     break;
776 
777   case tok::greatergreatergreater:
778     RemainingToken = tok::greatergreater;
779     break;
780 
781   case tok::greaterequal:
782     RemainingToken = tok::equal;
783     ReplacementStr = "> =";
784     break;
785 
786   case tok::greatergreaterequal:
787     RemainingToken = tok::greaterequal;
788     break;
789   }
790 
791   // This template-id is terminated by a token which starts with a '>'. Outside
792   // C++11, this is now error recovery, and in C++11, this is error recovery if
793   // the token isn't '>>' or '>>>'.
794   // '>>>' is for CUDA, where this sequence of characters is parsed into
795   // tok::greatergreatergreater, rather than two separate tokens.
796   //
797   // We always allow this for Objective-C type parameter and type argument
798   // lists.
799   RAngleLoc = Tok.getLocation();
800   Token Next = NextToken();
801   if (!ObjCGenericList) {
802     // The source range of the '>>' or '>=' at the start of the token.
803     CharSourceRange ReplacementRange =
804         CharSourceRange::getCharRange(RAngleLoc,
805             Lexer::AdvanceToTokenCharacter(RAngleLoc, 2, PP.getSourceManager(),
806                                            getLangOpts()));
807 
808     // A hint to put a space between the '>>'s. In order to make the hint as
809     // clear as possible, we include the characters either side of the space in
810     // the replacement, rather than just inserting a space at SecondCharLoc.
811     FixItHint Hint1 = FixItHint::CreateReplacement(ReplacementRange,
812                                                    ReplacementStr);
813 
814     // A hint to put another space after the token, if it would otherwise be
815     // lexed differently.
816     FixItHint Hint2;
817     if ((RemainingToken == tok::greater ||
818          RemainingToken == tok::greatergreater) &&
819         (Next.isOneOf(tok::greater, tok::greatergreater,
820                       tok::greatergreatergreater, tok::equal,
821                       tok::greaterequal, tok::greatergreaterequal,
822                       tok::equalequal)) &&
823         areTokensAdjacent(Tok, Next))
824       Hint2 = FixItHint::CreateInsertion(Next.getLocation(), " ");
825 
826     unsigned DiagId = diag::err_two_right_angle_brackets_need_space;
827     if (getLangOpts().CPlusPlus11 &&
828         (Tok.is(tok::greatergreater) || Tok.is(tok::greatergreatergreater)))
829       DiagId = diag::warn_cxx98_compat_two_right_angle_brackets;
830     else if (Tok.is(tok::greaterequal))
831       DiagId = diag::err_right_angle_bracket_equal_needs_space;
832     Diag(Tok.getLocation(), DiagId) << Hint1 << Hint2;
833   }
834 
835   // Strip the initial '>' from the token.
836   Token PrevTok = Tok;
837   if (RemainingToken == tok::equal && Next.is(tok::equal) &&
838       areTokensAdjacent(Tok, Next)) {
839     // Join two adjacent '=' tokens into one, for cases like:
840     //   void (*p)() = f<int>;
841     //   return f<int>==p;
842     ConsumeToken();
843     Tok.setKind(tok::equalequal);
844     Tok.setLength(Tok.getLength() + 1);
845   } else {
846     Tok.setKind(RemainingToken);
847     Tok.setLength(Tok.getLength() - 1);
848   }
849   Tok.setLocation(Lexer::AdvanceToTokenCharacter(RAngleLoc, 1,
850                                                  PP.getSourceManager(),
851                                                  getLangOpts()));
852 
853   // The advance from '>>' to '>' in a ObjectiveC template argument list needs
854   // to be properly reflected in the token cache to allow correct interaction
855   // between annotation and backtracking.
856   if (ObjCGenericList && PrevTok.getKind() == tok::greatergreater &&
857       RemainingToken == tok::greater && PP.IsPreviousCachedToken(PrevTok)) {
858     PrevTok.setKind(RemainingToken);
859     PrevTok.setLength(1);
860     // Break tok::greatergreater into two tok::greater but only add the second
861     // one in case the client asks to consume the last token.
862     if (ConsumeLastToken)
863       PP.ReplacePreviousCachedToken({PrevTok, Tok});
864     else
865       PP.ReplacePreviousCachedToken({PrevTok});
866   }
867 
868   if (!ConsumeLastToken) {
869     // Since we're not supposed to consume the '>' token, we need to push
870     // this token and revert the current token back to the '>'.
871     PP.EnterToken(Tok);
872     Tok.setKind(tok::greater);
873     Tok.setLength(1);
874     Tok.setLocation(RAngleLoc);
875   }
876   return false;
877 }
878 
879 
880 /// \brief Parses a template-id that after the template name has
881 /// already been parsed.
882 ///
883 /// This routine takes care of parsing the enclosed template argument
884 /// list ('<' template-parameter-list [opt] '>') and placing the
885 /// results into a form that can be transferred to semantic analysis.
886 ///
887 /// \param Template the template declaration produced by isTemplateName
888 ///
889 /// \param TemplateNameLoc the source location of the template name
890 ///
891 /// \param SS if non-NULL, the nested-name-specifier preceding the
892 /// template name.
893 ///
894 /// \param ConsumeLastToken if true, then we will consume the last
895 /// token that forms the template-id. Otherwise, we will leave the
896 /// last token in the stream (e.g., so that it can be replaced with an
897 /// annotation token).
898 bool
ParseTemplateIdAfterTemplateName(TemplateTy Template,SourceLocation TemplateNameLoc,const CXXScopeSpec & SS,bool ConsumeLastToken,SourceLocation & LAngleLoc,TemplateArgList & TemplateArgs,SourceLocation & RAngleLoc)899 Parser::ParseTemplateIdAfterTemplateName(TemplateTy Template,
900                                          SourceLocation TemplateNameLoc,
901                                          const CXXScopeSpec &SS,
902                                          bool ConsumeLastToken,
903                                          SourceLocation &LAngleLoc,
904                                          TemplateArgList &TemplateArgs,
905                                          SourceLocation &RAngleLoc) {
906   assert(Tok.is(tok::less) && "Must have already parsed the template-name");
907 
908   // Consume the '<'.
909   LAngleLoc = ConsumeToken();
910 
911   // Parse the optional template-argument-list.
912   bool Invalid = false;
913   {
914     GreaterThanIsOperatorScope G(GreaterThanIsOperator, false);
915     if (Tok.isNot(tok::greater) && Tok.isNot(tok::greatergreater))
916       Invalid = ParseTemplateArgumentList(TemplateArgs);
917 
918     if (Invalid) {
919       // Try to find the closing '>'.
920       if (ConsumeLastToken)
921         SkipUntil(tok::greater, StopAtSemi);
922       else
923         SkipUntil(tok::greater, StopAtSemi | StopBeforeMatch);
924       return true;
925     }
926   }
927 
928   return ParseGreaterThanInTemplateList(RAngleLoc, ConsumeLastToken,
929                                         /*ObjCGenericList=*/false);
930 }
931 
932 /// \brief Replace the tokens that form a simple-template-id with an
933 /// annotation token containing the complete template-id.
934 ///
935 /// The first token in the stream must be the name of a template that
936 /// is followed by a '<'. This routine will parse the complete
937 /// simple-template-id and replace the tokens with a single annotation
938 /// token with one of two different kinds: if the template-id names a
939 /// type (and \p AllowTypeAnnotation is true), the annotation token is
940 /// a type annotation that includes the optional nested-name-specifier
941 /// (\p SS). Otherwise, the annotation token is a template-id
942 /// annotation that does not include the optional
943 /// nested-name-specifier.
944 ///
945 /// \param Template  the declaration of the template named by the first
946 /// token (an identifier), as returned from \c Action::isTemplateName().
947 ///
948 /// \param TNK the kind of template that \p Template
949 /// refers to, as returned from \c Action::isTemplateName().
950 ///
951 /// \param SS if non-NULL, the nested-name-specifier that precedes
952 /// this template name.
953 ///
954 /// \param TemplateKWLoc if valid, specifies that this template-id
955 /// annotation was preceded by the 'template' keyword and gives the
956 /// location of that keyword. If invalid (the default), then this
957 /// template-id was not preceded by a 'template' keyword.
958 ///
959 /// \param AllowTypeAnnotation if true (the default), then a
960 /// simple-template-id that refers to a class template, template
961 /// template parameter, or other template that produces a type will be
962 /// replaced with a type annotation token. Otherwise, the
963 /// simple-template-id is always replaced with a template-id
964 /// annotation token.
965 ///
966 /// If an unrecoverable parse error occurs and no annotation token can be
967 /// formed, this function returns true.
968 ///
AnnotateTemplateIdToken(TemplateTy Template,TemplateNameKind TNK,CXXScopeSpec & SS,SourceLocation TemplateKWLoc,UnqualifiedId & TemplateName,bool AllowTypeAnnotation)969 bool Parser::AnnotateTemplateIdToken(TemplateTy Template, TemplateNameKind TNK,
970                                      CXXScopeSpec &SS,
971                                      SourceLocation TemplateKWLoc,
972                                      UnqualifiedId &TemplateName,
973                                      bool AllowTypeAnnotation) {
974   assert(getLangOpts().CPlusPlus && "Can only annotate template-ids in C++");
975   assert(Template && Tok.is(tok::less) &&
976          "Parser isn't at the beginning of a template-id");
977 
978   // Consume the template-name.
979   SourceLocation TemplateNameLoc = TemplateName.getSourceRange().getBegin();
980 
981   // Parse the enclosed template argument list.
982   SourceLocation LAngleLoc, RAngleLoc;
983   TemplateArgList TemplateArgs;
984   bool Invalid = ParseTemplateIdAfterTemplateName(Template,
985                                                   TemplateNameLoc,
986                                                   SS, false, LAngleLoc,
987                                                   TemplateArgs,
988                                                   RAngleLoc);
989 
990   if (Invalid) {
991     // If we failed to parse the template ID but skipped ahead to a >, we're not
992     // going to be able to form a token annotation.  Eat the '>' if present.
993     TryConsumeToken(tok::greater);
994     return true;
995   }
996 
997   ASTTemplateArgsPtr TemplateArgsPtr(TemplateArgs);
998 
999   // Build the annotation token.
1000   if (TNK == TNK_Type_template && AllowTypeAnnotation) {
1001     TypeResult Type
1002       = Actions.ActOnTemplateIdType(SS, TemplateKWLoc,
1003                                     Template, TemplateNameLoc,
1004                                     LAngleLoc, TemplateArgsPtr, RAngleLoc);
1005     if (Type.isInvalid()) {
1006       // If we failed to parse the template ID but skipped ahead to a >, we're not
1007       // going to be able to form a token annotation.  Eat the '>' if present.
1008       TryConsumeToken(tok::greater);
1009       return true;
1010     }
1011 
1012     Tok.setKind(tok::annot_typename);
1013     setTypeAnnotation(Tok, Type.get());
1014     if (SS.isNotEmpty())
1015       Tok.setLocation(SS.getBeginLoc());
1016     else if (TemplateKWLoc.isValid())
1017       Tok.setLocation(TemplateKWLoc);
1018     else
1019       Tok.setLocation(TemplateNameLoc);
1020   } else {
1021     // Build a template-id annotation token that can be processed
1022     // later.
1023     Tok.setKind(tok::annot_template_id);
1024     TemplateIdAnnotation *TemplateId
1025       = TemplateIdAnnotation::Allocate(TemplateArgs.size(), TemplateIds);
1026     TemplateId->TemplateNameLoc = TemplateNameLoc;
1027     if (TemplateName.getKind() == UnqualifiedId::IK_Identifier) {
1028       TemplateId->Name = TemplateName.Identifier;
1029       TemplateId->Operator = OO_None;
1030     } else {
1031       TemplateId->Name = nullptr;
1032       TemplateId->Operator = TemplateName.OperatorFunctionId.Operator;
1033     }
1034     TemplateId->SS = SS;
1035     TemplateId->TemplateKWLoc = TemplateKWLoc;
1036     TemplateId->Template = Template;
1037     TemplateId->Kind = TNK;
1038     TemplateId->LAngleLoc = LAngleLoc;
1039     TemplateId->RAngleLoc = RAngleLoc;
1040     ParsedTemplateArgument *Args = TemplateId->getTemplateArgs();
1041     for (unsigned Arg = 0, ArgEnd = TemplateArgs.size(); Arg != ArgEnd; ++Arg)
1042       Args[Arg] = ParsedTemplateArgument(TemplateArgs[Arg]);
1043     Tok.setAnnotationValue(TemplateId);
1044     if (TemplateKWLoc.isValid())
1045       Tok.setLocation(TemplateKWLoc);
1046     else
1047       Tok.setLocation(TemplateNameLoc);
1048   }
1049 
1050   // Common fields for the annotation token
1051   Tok.setAnnotationEndLoc(RAngleLoc);
1052 
1053   // In case the tokens were cached, have Preprocessor replace them with the
1054   // annotation token.
1055   PP.AnnotateCachedTokens(Tok);
1056   return false;
1057 }
1058 
1059 /// \brief Replaces a template-id annotation token with a type
1060 /// annotation token.
1061 ///
1062 /// If there was a failure when forming the type from the template-id,
1063 /// a type annotation token will still be created, but will have a
1064 /// NULL type pointer to signify an error.
AnnotateTemplateIdTokenAsType()1065 void Parser::AnnotateTemplateIdTokenAsType() {
1066   assert(Tok.is(tok::annot_template_id) && "Requires template-id tokens");
1067 
1068   TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok);
1069   assert((TemplateId->Kind == TNK_Type_template ||
1070           TemplateId->Kind == TNK_Dependent_template_name) &&
1071          "Only works for type and dependent templates");
1072 
1073   ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
1074                                      TemplateId->NumArgs);
1075 
1076   TypeResult Type
1077     = Actions.ActOnTemplateIdType(TemplateId->SS,
1078                                   TemplateId->TemplateKWLoc,
1079                                   TemplateId->Template,
1080                                   TemplateId->TemplateNameLoc,
1081                                   TemplateId->LAngleLoc,
1082                                   TemplateArgsPtr,
1083                                   TemplateId->RAngleLoc);
1084   // Create the new "type" annotation token.
1085   Tok.setKind(tok::annot_typename);
1086   setTypeAnnotation(Tok, Type.isInvalid() ? nullptr : Type.get());
1087   if (TemplateId->SS.isNotEmpty()) // it was a C++ qualified type name.
1088     Tok.setLocation(TemplateId->SS.getBeginLoc());
1089   // End location stays the same
1090 
1091   // Replace the template-id annotation token, and possible the scope-specifier
1092   // that precedes it, with the typename annotation token.
1093   PP.AnnotateCachedTokens(Tok);
1094 }
1095 
1096 /// \brief Determine whether the given token can end a template argument.
isEndOfTemplateArgument(Token Tok)1097 static bool isEndOfTemplateArgument(Token Tok) {
1098   return Tok.isOneOf(tok::comma, tok::greater, tok::greatergreater);
1099 }
1100 
1101 /// \brief Parse a C++ template template argument.
ParseTemplateTemplateArgument()1102 ParsedTemplateArgument Parser::ParseTemplateTemplateArgument() {
1103   if (!Tok.is(tok::identifier) && !Tok.is(tok::coloncolon) &&
1104       !Tok.is(tok::annot_cxxscope))
1105     return ParsedTemplateArgument();
1106 
1107   // C++0x [temp.arg.template]p1:
1108   //   A template-argument for a template template-parameter shall be the name
1109   //   of a class template or an alias template, expressed as id-expression.
1110   //
1111   // We parse an id-expression that refers to a class template or alias
1112   // template. The grammar we parse is:
1113   //
1114   //   nested-name-specifier[opt] template[opt] identifier ...[opt]
1115   //
1116   // followed by a token that terminates a template argument, such as ',',
1117   // '>', or (in some cases) '>>'.
1118   CXXScopeSpec SS; // nested-name-specifier, if present
1119   ParseOptionalCXXScopeSpecifier(SS, nullptr,
1120                                  /*EnteringContext=*/false);
1121 
1122   ParsedTemplateArgument Result;
1123   SourceLocation EllipsisLoc;
1124   if (SS.isSet() && Tok.is(tok::kw_template)) {
1125     // Parse the optional 'template' keyword following the
1126     // nested-name-specifier.
1127     SourceLocation TemplateKWLoc = ConsumeToken();
1128 
1129     if (Tok.is(tok::identifier)) {
1130       // We appear to have a dependent template name.
1131       UnqualifiedId Name;
1132       Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation());
1133       ConsumeToken(); // the identifier
1134 
1135       TryConsumeToken(tok::ellipsis, EllipsisLoc);
1136 
1137       // If the next token signals the end of a template argument,
1138       // then we have a dependent template name that could be a template
1139       // template argument.
1140       TemplateTy Template;
1141       if (isEndOfTemplateArgument(Tok) &&
1142           Actions.ActOnDependentTemplateName(
1143               getCurScope(), SS, TemplateKWLoc, Name,
1144               /*ObjectType=*/nullptr,
1145               /*EnteringContext=*/false, Template))
1146         Result = ParsedTemplateArgument(SS, Template, Name.StartLocation);
1147     }
1148   } else if (Tok.is(tok::identifier)) {
1149     // We may have a (non-dependent) template name.
1150     TemplateTy Template;
1151     UnqualifiedId Name;
1152     Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation());
1153     ConsumeToken(); // the identifier
1154 
1155     TryConsumeToken(tok::ellipsis, EllipsisLoc);
1156 
1157     if (isEndOfTemplateArgument(Tok)) {
1158       bool MemberOfUnknownSpecialization;
1159       TemplateNameKind TNK = Actions.isTemplateName(
1160           getCurScope(), SS,
1161           /*hasTemplateKeyword=*/false, Name,
1162           /*ObjectType=*/nullptr,
1163           /*EnteringContext=*/false, Template, MemberOfUnknownSpecialization);
1164       if (TNK == TNK_Dependent_template_name || TNK == TNK_Type_template) {
1165         // We have an id-expression that refers to a class template or
1166         // (C++0x) alias template.
1167         Result = ParsedTemplateArgument(SS, Template, Name.StartLocation);
1168       }
1169     }
1170   }
1171 
1172   // If this is a pack expansion, build it as such.
1173   if (EllipsisLoc.isValid() && !Result.isInvalid())
1174     Result = Actions.ActOnPackExpansion(Result, EllipsisLoc);
1175 
1176   return Result;
1177 }
1178 
1179 /// ParseTemplateArgument - Parse a C++ template argument (C++ [temp.names]).
1180 ///
1181 ///       template-argument: [C++ 14.2]
1182 ///         constant-expression
1183 ///         type-id
1184 ///         id-expression
ParseTemplateArgument()1185 ParsedTemplateArgument Parser::ParseTemplateArgument() {
1186   // C++ [temp.arg]p2:
1187   //   In a template-argument, an ambiguity between a type-id and an
1188   //   expression is resolved to a type-id, regardless of the form of
1189   //   the corresponding template-parameter.
1190   //
1191   // Therefore, we initially try to parse a type-id.
1192   if (isCXXTypeId(TypeIdAsTemplateArgument)) {
1193     SourceLocation Loc = Tok.getLocation();
1194     TypeResult TypeArg = ParseTypeName(/*Range=*/nullptr,
1195                                        Declarator::TemplateTypeArgContext);
1196     if (TypeArg.isInvalid())
1197       return ParsedTemplateArgument();
1198 
1199     return ParsedTemplateArgument(ParsedTemplateArgument::Type,
1200                                   TypeArg.get().getAsOpaquePtr(),
1201                                   Loc);
1202   }
1203 
1204   // Try to parse a template template argument.
1205   {
1206     TentativeParsingAction TPA(*this);
1207 
1208     ParsedTemplateArgument TemplateTemplateArgument
1209       = ParseTemplateTemplateArgument();
1210     if (!TemplateTemplateArgument.isInvalid()) {
1211       TPA.Commit();
1212       return TemplateTemplateArgument;
1213     }
1214 
1215     // Revert this tentative parse to parse a non-type template argument.
1216     TPA.Revert();
1217   }
1218 
1219   // Parse a non-type template argument.
1220   SourceLocation Loc = Tok.getLocation();
1221   ExprResult ExprArg = ParseConstantExpression(MaybeTypeCast);
1222   if (ExprArg.isInvalid() || !ExprArg.get())
1223     return ParsedTemplateArgument();
1224 
1225   return ParsedTemplateArgument(ParsedTemplateArgument::NonType,
1226                                 ExprArg.get(), Loc);
1227 }
1228 
1229 /// \brief Determine whether the current tokens can only be parsed as a
1230 /// template argument list (starting with the '<') and never as a '<'
1231 /// expression.
IsTemplateArgumentList(unsigned Skip)1232 bool Parser::IsTemplateArgumentList(unsigned Skip) {
1233   struct AlwaysRevertAction : TentativeParsingAction {
1234     AlwaysRevertAction(Parser &P) : TentativeParsingAction(P) { }
1235     ~AlwaysRevertAction() { Revert(); }
1236   } Tentative(*this);
1237 
1238   while (Skip) {
1239     ConsumeToken();
1240     --Skip;
1241   }
1242 
1243   // '<'
1244   if (!TryConsumeToken(tok::less))
1245     return false;
1246 
1247   // An empty template argument list.
1248   if (Tok.is(tok::greater))
1249     return true;
1250 
1251   // See whether we have declaration specifiers, which indicate a type.
1252   while (isCXXDeclarationSpecifier() == TPResult::True)
1253     ConsumeToken();
1254 
1255   // If we have a '>' or a ',' then this is a template argument list.
1256   return Tok.isOneOf(tok::greater, tok::comma);
1257 }
1258 
1259 /// ParseTemplateArgumentList - Parse a C++ template-argument-list
1260 /// (C++ [temp.names]). Returns true if there was an error.
1261 ///
1262 ///       template-argument-list: [C++ 14.2]
1263 ///         template-argument
1264 ///         template-argument-list ',' template-argument
1265 bool
ParseTemplateArgumentList(TemplateArgList & TemplateArgs)1266 Parser::ParseTemplateArgumentList(TemplateArgList &TemplateArgs) {
1267   // Template argument lists are constant-evaluation contexts.
1268   EnterExpressionEvaluationContext EvalContext(Actions,Sema::ConstantEvaluated);
1269   ColonProtectionRAIIObject ColonProtection(*this, false);
1270 
1271   do {
1272     ParsedTemplateArgument Arg = ParseTemplateArgument();
1273     SourceLocation EllipsisLoc;
1274     if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
1275       Arg = Actions.ActOnPackExpansion(Arg, EllipsisLoc);
1276 
1277     if (Arg.isInvalid()) {
1278       SkipUntil(tok::comma, tok::greater, StopAtSemi | StopBeforeMatch);
1279       return true;
1280     }
1281 
1282     // Save this template argument.
1283     TemplateArgs.push_back(Arg);
1284 
1285     // If the next token is a comma, consume it and keep reading
1286     // arguments.
1287   } while (TryConsumeToken(tok::comma));
1288 
1289   return false;
1290 }
1291 
1292 /// \brief Parse a C++ explicit template instantiation
1293 /// (C++ [temp.explicit]).
1294 ///
1295 ///       explicit-instantiation:
1296 ///         'extern' [opt] 'template' declaration
1297 ///
1298 /// Note that the 'extern' is a GNU extension and C++11 feature.
ParseExplicitInstantiation(unsigned Context,SourceLocation ExternLoc,SourceLocation TemplateLoc,SourceLocation & DeclEnd,AccessSpecifier AS)1299 Decl *Parser::ParseExplicitInstantiation(unsigned Context,
1300                                          SourceLocation ExternLoc,
1301                                          SourceLocation TemplateLoc,
1302                                          SourceLocation &DeclEnd,
1303                                          AccessSpecifier AS) {
1304   // This isn't really required here.
1305   ParsingDeclRAIIObject
1306     ParsingTemplateParams(*this, ParsingDeclRAIIObject::NoParent);
1307 
1308   return ParseSingleDeclarationAfterTemplate(Context,
1309                                              ParsedTemplateInfo(ExternLoc,
1310                                                                 TemplateLoc),
1311                                              ParsingTemplateParams,
1312                                              DeclEnd, AS);
1313 }
1314 
getSourceRange() const1315 SourceRange Parser::ParsedTemplateInfo::getSourceRange() const {
1316   if (TemplateParams)
1317     return getTemplateParamsRange(TemplateParams->data(),
1318                                   TemplateParams->size());
1319 
1320   SourceRange R(TemplateLoc);
1321   if (ExternLoc.isValid())
1322     R.setBegin(ExternLoc);
1323   return R;
1324 }
1325 
LateTemplateParserCallback(void * P,LateParsedTemplate & LPT)1326 void Parser::LateTemplateParserCallback(void *P, LateParsedTemplate &LPT) {
1327   ((Parser *)P)->ParseLateTemplatedFuncDef(LPT);
1328 }
1329 
1330 /// \brief Late parse a C++ function template in Microsoft mode.
ParseLateTemplatedFuncDef(LateParsedTemplate & LPT)1331 void Parser::ParseLateTemplatedFuncDef(LateParsedTemplate &LPT) {
1332   if (!LPT.D)
1333      return;
1334 
1335   // Get the FunctionDecl.
1336   FunctionDecl *FunD = LPT.D->getAsFunction();
1337   // Track template parameter depth.
1338   TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth);
1339 
1340   // To restore the context after late parsing.
1341   Sema::ContextRAII GlobalSavedContext(
1342       Actions, Actions.Context.getTranslationUnitDecl());
1343 
1344   SmallVector<ParseScope*, 4> TemplateParamScopeStack;
1345 
1346   // Get the list of DeclContexts to reenter.
1347   SmallVector<DeclContext*, 4> DeclContextsToReenter;
1348   DeclContext *DD = FunD;
1349   while (DD && !DD->isTranslationUnit()) {
1350     DeclContextsToReenter.push_back(DD);
1351     DD = DD->getLexicalParent();
1352   }
1353 
1354   // Reenter template scopes from outermost to innermost.
1355   SmallVectorImpl<DeclContext *>::reverse_iterator II =
1356       DeclContextsToReenter.rbegin();
1357   for (; II != DeclContextsToReenter.rend(); ++II) {
1358     TemplateParamScopeStack.push_back(new ParseScope(this,
1359           Scope::TemplateParamScope));
1360     unsigned NumParamLists =
1361       Actions.ActOnReenterTemplateScope(getCurScope(), cast<Decl>(*II));
1362     CurTemplateDepthTracker.addDepth(NumParamLists);
1363     if (*II != FunD) {
1364       TemplateParamScopeStack.push_back(new ParseScope(this, Scope::DeclScope));
1365       Actions.PushDeclContext(Actions.getCurScope(), *II);
1366     }
1367   }
1368 
1369   assert(!LPT.Toks.empty() && "Empty body!");
1370 
1371   // Append the current token at the end of the new token stream so that it
1372   // doesn't get lost.
1373   LPT.Toks.push_back(Tok);
1374   PP.EnterTokenStream(LPT.Toks, true);
1375 
1376   // Consume the previously pushed token.
1377   ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);
1378   assert(Tok.isOneOf(tok::l_brace, tok::colon, tok::kw_try) &&
1379          "Inline method not starting with '{', ':' or 'try'");
1380 
1381   // Parse the method body. Function body parsing code is similar enough
1382   // to be re-used for method bodies as well.
1383   ParseScope FnScope(this, Scope::FnScope|Scope::DeclScope);
1384 
1385   // Recreate the containing function DeclContext.
1386   Sema::ContextRAII FunctionSavedContext(Actions,
1387                                          Actions.getContainingDC(FunD));
1388 
1389   Actions.ActOnStartOfFunctionDef(getCurScope(), FunD);
1390 
1391   if (Tok.is(tok::kw_try)) {
1392     ParseFunctionTryBlock(LPT.D, FnScope);
1393   } else {
1394     if (Tok.is(tok::colon))
1395       ParseConstructorInitializer(LPT.D);
1396     else
1397       Actions.ActOnDefaultCtorInitializers(LPT.D);
1398 
1399     if (Tok.is(tok::l_brace)) {
1400       assert((!isa<FunctionTemplateDecl>(LPT.D) ||
1401               cast<FunctionTemplateDecl>(LPT.D)
1402                       ->getTemplateParameters()
1403                       ->getDepth() == TemplateParameterDepth - 1) &&
1404              "TemplateParameterDepth should be greater than the depth of "
1405              "current template being instantiated!");
1406       ParseFunctionStatementBody(LPT.D, FnScope);
1407       Actions.UnmarkAsLateParsedTemplate(FunD);
1408     } else
1409       Actions.ActOnFinishFunctionBody(LPT.D, nullptr);
1410   }
1411 
1412   // Exit scopes.
1413   FnScope.Exit();
1414   SmallVectorImpl<ParseScope *>::reverse_iterator I =
1415    TemplateParamScopeStack.rbegin();
1416   for (; I != TemplateParamScopeStack.rend(); ++I)
1417     delete *I;
1418 }
1419 
1420 /// \brief Lex a delayed template function for late parsing.
LexTemplateFunctionForLateParsing(CachedTokens & Toks)1421 void Parser::LexTemplateFunctionForLateParsing(CachedTokens &Toks) {
1422   tok::TokenKind kind = Tok.getKind();
1423   if (!ConsumeAndStoreFunctionPrologue(Toks)) {
1424     // Consume everything up to (and including) the matching right brace.
1425     ConsumeAndStoreUntil(tok::r_brace, Toks, /*StopAtSemi=*/false);
1426   }
1427 
1428   // If we're in a function-try-block, we need to store all the catch blocks.
1429   if (kind == tok::kw_try) {
1430     while (Tok.is(tok::kw_catch)) {
1431       ConsumeAndStoreUntil(tok::l_brace, Toks, /*StopAtSemi=*/false);
1432       ConsumeAndStoreUntil(tok::r_brace, Toks, /*StopAtSemi=*/false);
1433     }
1434   }
1435 }
1436