clang  3.7.0
ParseTemplate.cpp
Go to the documentation of this file.
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"
20 #include "clang/Sema/DeclSpec.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 *
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,
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 *
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.
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  ParamLists.push_back(
126  Actions.ActOnTemplateParameterList(CurTemplateDepthTracker.getDepth(),
127  ExportLoc,
128  TemplateLoc, LAngleLoc,
129  TemplateParams.data(),
130  TemplateParams.size(), RAngleLoc));
131 
132  if (!TemplateParams.empty()) {
133  isSpecialization = false;
134  ++CurTemplateDepthTracker;
135 
136  if (TryConsumeToken(tok::kw_requires)) {
137  ExprResult ER =
139  if (!ER.isUsable()) {
140  // Skip until the semi-colon or a '}'.
141  SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch);
142  TryConsumeToken(tok::semi);
143  return nullptr;
144  }
145  }
146  } else {
147  LastParamListWasEmpty = true;
148  }
149  } while (Tok.isOneOf(tok::kw_export, tok::kw_template));
150 
151  // Parse the actual template declaration.
152  return ParseSingleDeclarationAfterTemplate(Context,
153  ParsedTemplateInfo(&ParamLists,
154  isSpecialization,
155  LastParamListWasEmpty),
156  ParsingTemplateParams,
157  DeclEnd, AS, AccessAttrs);
158 }
159 
160 /// \brief Parse a single declaration that declares a template,
161 /// template specialization, or explicit instantiation of a template.
162 ///
163 /// \param DeclEnd will receive the source location of the last token
164 /// within this declaration.
165 ///
166 /// \param AS the access specifier associated with this
167 /// declaration. Will be AS_none for namespace-scope declarations.
168 ///
169 /// \returns the new declaration.
170 Decl *
171 Parser::ParseSingleDeclarationAfterTemplate(
172  unsigned Context,
173  const ParsedTemplateInfo &TemplateInfo,
174  ParsingDeclRAIIObject &DiagsFromTParams,
175  SourceLocation &DeclEnd,
176  AccessSpecifier AS,
177  AttributeList *AccessAttrs) {
178  assert(TemplateInfo.Kind != ParsedTemplateInfo::NonTemplate &&
179  "Template information required");
180 
181  if (Tok.is(tok::kw_static_assert)) {
182  // A static_assert declaration may not be templated.
183  Diag(Tok.getLocation(), diag::err_templated_invalid_declaration)
184  << TemplateInfo.getSourceRange();
185  // Parse the static_assert declaration to improve error recovery.
186  return ParseStaticAssertDeclaration(DeclEnd);
187  }
188 
189  if (Context == Declarator::MemberContext) {
190  // We are parsing a member template.
191  ParseCXXClassMemberDeclaration(AS, AccessAttrs, TemplateInfo,
192  &DiagsFromTParams);
193  return nullptr;
194  }
195 
196  ParsedAttributesWithRange prefixAttrs(AttrFactory);
197  MaybeParseCXX11Attributes(prefixAttrs);
198 
199  if (Tok.is(tok::kw_using))
200  return ParseUsingDirectiveOrDeclaration(Context, TemplateInfo, DeclEnd,
201  prefixAttrs);
202 
203  // Parse the declaration specifiers, stealing any diagnostics from
204  // the template parameters.
205  ParsingDeclSpec DS(*this, &DiagsFromTParams);
206 
207  ParseDeclarationSpecifiers(DS, TemplateInfo, AS,
208  getDeclSpecContextFromDeclaratorContext(Context));
209 
210  if (Tok.is(tok::semi)) {
211  ProhibitAttributes(prefixAttrs);
212  DeclEnd = ConsumeToken();
214  getCurScope(), AS, DS,
215  TemplateInfo.TemplateParams ? *TemplateInfo.TemplateParams
217  TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation);
218  DS.complete(Decl);
219  return Decl;
220  }
221 
222  // Move the attributes from the prefix into the DS.
223  if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation)
224  ProhibitAttributes(prefixAttrs);
225  else
226  DS.takeAttributesFrom(prefixAttrs);
227 
228  // Parse the declarator.
229  ParsingDeclarator DeclaratorInfo(*this, DS, (Declarator::TheContext)Context);
230  ParseDeclarator(DeclaratorInfo);
231  // Error parsing the declarator?
232  if (!DeclaratorInfo.hasName()) {
233  // If so, skip until the semi-colon or a }.
234  SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch);
235  if (Tok.is(tok::semi))
236  ConsumeToken();
237  return nullptr;
238  }
239 
240  LateParsedAttrList LateParsedAttrs(true);
241  if (DeclaratorInfo.isFunctionDeclarator())
242  MaybeParseGNUAttributes(DeclaratorInfo, &LateParsedAttrs);
243 
244  if (DeclaratorInfo.isFunctionDeclarator() &&
245  isStartOfFunctionDefinition(DeclaratorInfo)) {
246 
247  // Function definitions are only allowed at file scope and in C++ classes.
248  // The C++ inline method definition case is handled elsewhere, so we only
249  // need to handle the file scope definition case.
250  if (Context != Declarator::FileContext) {
251  Diag(Tok, diag::err_function_definition_not_allowed);
253  return nullptr;
254  }
255 
256  if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef) {
257  // Recover by ignoring the 'typedef'. This was probably supposed to be
258  // the 'typename' keyword, which we should have already suggested adding
259  // if it's appropriate.
260  Diag(DS.getStorageClassSpecLoc(), diag::err_function_declared_typedef)
261  << FixItHint::CreateRemoval(DS.getStorageClassSpecLoc());
262  DS.ClearStorageClassSpecs();
263  }
264 
265  if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation) {
266  if (DeclaratorInfo.getName().getKind() != UnqualifiedId::IK_TemplateId) {
267  // If the declarator-id is not a template-id, issue a diagnostic and
268  // recover by ignoring the 'template' keyword.
269  Diag(Tok, diag::err_template_defn_explicit_instantiation) << 0;
270  return ParseFunctionDefinition(DeclaratorInfo, ParsedTemplateInfo(),
271  &LateParsedAttrs);
272  } else {
273  SourceLocation LAngleLoc
274  = PP.getLocForEndOfToken(TemplateInfo.TemplateLoc);
275  Diag(DeclaratorInfo.getIdentifierLoc(),
276  diag::err_explicit_instantiation_with_definition)
277  << SourceRange(TemplateInfo.TemplateLoc)
278  << FixItHint::CreateInsertion(LAngleLoc, "<>");
279 
280  // Recover as if it were an explicit specialization.
281  TemplateParameterLists FakedParamLists;
282  FakedParamLists.push_back(Actions.ActOnTemplateParameterList(
283  0, SourceLocation(), TemplateInfo.TemplateLoc, LAngleLoc, nullptr,
284  0, LAngleLoc));
285 
286  return ParseFunctionDefinition(
287  DeclaratorInfo, ParsedTemplateInfo(&FakedParamLists,
288  /*isSpecialization=*/true,
289  /*LastParamListWasEmpty=*/true),
290  &LateParsedAttrs);
291  }
292  }
293  return ParseFunctionDefinition(DeclaratorInfo, TemplateInfo,
294  &LateParsedAttrs);
295  }
296 
297  // Parse this declaration.
298  Decl *ThisDecl = ParseDeclarationAfterDeclarator(DeclaratorInfo,
299  TemplateInfo);
300 
301  if (Tok.is(tok::comma)) {
302  Diag(Tok, diag::err_multiple_template_declarators)
303  << (int)TemplateInfo.Kind;
304  SkipUntil(tok::semi);
305  return ThisDecl;
306  }
307 
308  // Eat the semi colon after the declaration.
309  ExpectAndConsumeSemi(diag::err_expected_semi_declaration);
310  if (LateParsedAttrs.size() > 0)
311  ParseLexedAttributeList(LateParsedAttrs, ThisDecl, true, false);
312  DeclaratorInfo.complete(ThisDecl);
313  return ThisDecl;
314 }
315 
316 /// ParseTemplateParameters - Parses a template-parameter-list enclosed in
317 /// angle brackets. Depth is the depth of this template-parameter-list, which
318 /// is the number of template headers directly enclosing this template header.
319 /// TemplateParams is the current list of template parameters we're building.
320 /// The template parameter we parse will be added to this list. LAngleLoc and
321 /// RAngleLoc will receive the positions of the '<' and '>', respectively,
322 /// that enclose this template parameter list.
323 ///
324 /// \returns true if an error occurred, false otherwise.
325 bool Parser::ParseTemplateParameters(unsigned Depth,
326  SmallVectorImpl<Decl*> &TemplateParams,
327  SourceLocation &LAngleLoc,
328  SourceLocation &RAngleLoc) {
329  // Get the template parameter list.
330  if (!TryConsumeToken(tok::less, LAngleLoc)) {
331  Diag(Tok.getLocation(), diag::err_expected_less_after) << "template";
332  return true;
333  }
334 
335  // Try to parse the template parameter list.
336  bool Failed = false;
337  if (!Tok.is(tok::greater) && !Tok.is(tok::greatergreater))
338  Failed = ParseTemplateParameterList(Depth, TemplateParams);
339 
340  if (Tok.is(tok::greatergreater)) {
341  // No diagnostic required here: a template-parameter-list can only be
342  // followed by a declaration or, for a template template parameter, the
343  // 'class' keyword. Therefore, the second '>' will be diagnosed later.
344  // This matters for elegant diagnosis of:
345  // template<template<typename>> struct S;
346  Tok.setKind(tok::greater);
347  RAngleLoc = Tok.getLocation();
349  } else if (!TryConsumeToken(tok::greater, RAngleLoc) && Failed) {
350  Diag(Tok.getLocation(), diag::err_expected) << tok::greater;
351  return true;
352  }
353  return false;
354 }
355 
356 /// ParseTemplateParameterList - Parse a template parameter list. If
357 /// the parsing fails badly (i.e., closing bracket was left out), this
358 /// will try to put the token stream in a reasonable position (closing
359 /// a statement, etc.) and return false.
360 ///
361 /// template-parameter-list: [C++ temp]
362 /// template-parameter
363 /// template-parameter-list ',' template-parameter
364 bool
365 Parser::ParseTemplateParameterList(unsigned Depth,
366  SmallVectorImpl<Decl*> &TemplateParams) {
367  while (1) {
368  if (Decl *TmpParam
369  = ParseTemplateParameter(Depth, TemplateParams.size())) {
370  TemplateParams.push_back(TmpParam);
371  } else {
372  // If we failed to parse a template parameter, skip until we find
373  // a comma or closing brace.
374  SkipUntil(tok::comma, tok::greater, tok::greatergreater,
376  }
377 
378  // Did we find a comma or the end of the template parameter list?
379  if (Tok.is(tok::comma)) {
380  ConsumeToken();
381  } else if (Tok.isOneOf(tok::greater, tok::greatergreater)) {
382  // Don't consume this... that's done by template parser.
383  break;
384  } else {
385  // Somebody probably forgot to close the template. Skip ahead and
386  // try to get out of the expression. This error is currently
387  // subsumed by whatever goes on in ParseTemplateParameter.
388  Diag(Tok.getLocation(), diag::err_expected_comma_greater);
389  SkipUntil(tok::comma, tok::greater, tok::greatergreater,
391  return false;
392  }
393  }
394  return true;
395 }
396 
397 /// \brief Determine whether the parser is at the start of a template
398 /// type parameter.
399 bool Parser::isStartOfTemplateTypeParameter() {
400  if (Tok.is(tok::kw_class)) {
401  // "class" may be the start of an elaborated-type-specifier or a
402  // type-parameter. Per C++ [temp.param]p3, we prefer the type-parameter.
403  switch (NextToken().getKind()) {
404  case tok::equal:
405  case tok::comma:
406  case tok::greater:
407  case tok::greatergreater:
408  case tok::ellipsis:
409  return true;
410 
411  case tok::identifier:
412  // This may be either a type-parameter or an elaborated-type-specifier.
413  // We have to look further.
414  break;
415 
416  default:
417  return false;
418  }
419 
420  switch (GetLookAheadToken(2).getKind()) {
421  case tok::equal:
422  case tok::comma:
423  case tok::greater:
424  case tok::greatergreater:
425  return true;
426 
427  default:
428  return false;
429  }
430  }
431 
432  if (Tok.isNot(tok::kw_typename))
433  return false;
434 
435  // C++ [temp.param]p2:
436  // There is no semantic difference between class and typename in a
437  // template-parameter. typename followed by an unqualified-id
438  // names a template type parameter. typename followed by a
439  // qualified-id denotes the type in a non-type
440  // parameter-declaration.
441  Token Next = NextToken();
442 
443  // If we have an identifier, skip over it.
444  if (Next.getKind() == tok::identifier)
445  Next = GetLookAheadToken(2);
446 
447  switch (Next.getKind()) {
448  case tok::equal:
449  case tok::comma:
450  case tok::greater:
451  case tok::greatergreater:
452  case tok::ellipsis:
453  return true;
454 
455  default:
456  return false;
457  }
458 }
459 
460 /// ParseTemplateParameter - Parse a template-parameter (C++ [temp.param]).
461 ///
462 /// template-parameter: [C++ temp.param]
463 /// type-parameter
464 /// parameter-declaration
465 ///
466 /// type-parameter: (see below)
467 /// 'class' ...[opt] identifier[opt]
468 /// 'class' identifier[opt] '=' type-id
469 /// 'typename' ...[opt] identifier[opt]
470 /// 'typename' identifier[opt] '=' type-id
471 /// 'template' '<' template-parameter-list '>'
472 /// 'class' ...[opt] identifier[opt]
473 /// 'template' '<' template-parameter-list '>' 'class' identifier[opt]
474 /// = id-expression
475 Decl *Parser::ParseTemplateParameter(unsigned Depth, unsigned Position) {
476  if (isStartOfTemplateTypeParameter())
477  return ParseTypeParameter(Depth, Position);
478 
479  if (Tok.is(tok::kw_template))
480  return ParseTemplateTemplateParameter(Depth, Position);
481 
482  // If it's none of the above, then it must be a parameter declaration.
483  // NOTE: This will pick up errors in the closure of the template parameter
484  // list (e.g., template < ; Check here to implement >> style closures.
485  return ParseNonTypeTemplateParameter(Depth, Position);
486 }
487 
488 /// ParseTypeParameter - Parse a template type parameter (C++ [temp.param]).
489 /// Other kinds of template parameters are parsed in
490 /// ParseTemplateTemplateParameter and ParseNonTypeTemplateParameter.
491 ///
492 /// type-parameter: [C++ temp.param]
493 /// 'class' ...[opt][C++0x] identifier[opt]
494 /// 'class' identifier[opt] '=' type-id
495 /// 'typename' ...[opt][C++0x] identifier[opt]
496 /// 'typename' identifier[opt] '=' type-id
497 Decl *Parser::ParseTypeParameter(unsigned Depth, unsigned Position) {
498  assert(Tok.isOneOf(tok::kw_class, tok::kw_typename) &&
499  "A type-parameter starts with 'class' or 'typename'");
500 
501  // Consume the 'class' or 'typename' keyword.
502  bool TypenameKeyword = Tok.is(tok::kw_typename);
503  SourceLocation KeyLoc = ConsumeToken();
504 
505  // Grab the ellipsis (if given).
506  SourceLocation EllipsisLoc;
507  if (TryConsumeToken(tok::ellipsis, EllipsisLoc)) {
508  Diag(EllipsisLoc,
510  ? diag::warn_cxx98_compat_variadic_templates
511  : diag::ext_variadic_templates);
512  }
513 
514  // Grab the template parameter name (if given)
515  SourceLocation NameLoc;
516  IdentifierInfo *ParamName = nullptr;
517  if (Tok.is(tok::identifier)) {
518  ParamName = Tok.getIdentifierInfo();
519  NameLoc = ConsumeToken();
520  } else if (Tok.isOneOf(tok::equal, tok::comma, tok::greater,
521  tok::greatergreater)) {
522  // Unnamed template parameter. Don't have to do anything here, just
523  // don't consume this token.
524  } else {
525  Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
526  return nullptr;
527  }
528 
529  // Recover from misplaced ellipsis.
530  bool AlreadyHasEllipsis = EllipsisLoc.isValid();
531  if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
532  DiagnoseMisplacedEllipsis(EllipsisLoc, NameLoc, AlreadyHasEllipsis, true);
533 
534  // Grab a default argument (if available).
535  // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
536  // we introduce the type parameter into the local scope.
537  SourceLocation EqualLoc;
538  ParsedType DefaultArg;
539  if (TryConsumeToken(tok::equal, EqualLoc))
540  DefaultArg = ParseTypeName(/*Range=*/nullptr,
542 
543  return Actions.ActOnTypeParameter(getCurScope(), TypenameKeyword, EllipsisLoc,
544  KeyLoc, ParamName, NameLoc, Depth, Position,
545  EqualLoc, DefaultArg);
546 }
547 
548 /// ParseTemplateTemplateParameter - Handle the parsing of template
549 /// template parameters.
550 ///
551 /// type-parameter: [C++ temp.param]
552 /// 'template' '<' template-parameter-list '>' type-parameter-key
553 /// ...[opt] identifier[opt]
554 /// 'template' '<' template-parameter-list '>' type-parameter-key
555 /// identifier[opt] = id-expression
556 /// type-parameter-key:
557 /// 'class'
558 /// 'typename' [C++1z]
559 Decl *
560 Parser::ParseTemplateTemplateParameter(unsigned Depth, unsigned Position) {
561  assert(Tok.is(tok::kw_template) && "Expected 'template' keyword");
562 
563  // Handle the template <...> part.
564  SourceLocation TemplateLoc = ConsumeToken();
565  SmallVector<Decl*,8> TemplateParams;
566  SourceLocation LAngleLoc, RAngleLoc;
567  {
568  ParseScope TemplateParmScope(this, Scope::TemplateParamScope);
569  if (ParseTemplateParameters(Depth + 1, TemplateParams, LAngleLoc,
570  RAngleLoc)) {
571  return nullptr;
572  }
573  }
574 
575  // Provide an ExtWarn if the C++1z feature of using 'typename' here is used.
576  // Generate a meaningful error if the user forgot to put class before the
577  // identifier, comma, or greater. Provide a fixit if the identifier, comma,
578  // or greater appear immediately or after 'struct'. In the latter case,
579  // replace the keyword with 'class'.
580  if (!TryConsumeToken(tok::kw_class)) {
581  bool Replace = Tok.isOneOf(tok::kw_typename, tok::kw_struct);
582  const Token &Next = Tok.is(tok::kw_struct) ? NextToken() : Tok;
583  if (Tok.is(tok::kw_typename)) {
584  Diag(Tok.getLocation(),
585  getLangOpts().CPlusPlus1z
586  ? diag::warn_cxx14_compat_template_template_param_typename
587  : diag::ext_template_template_param_typename)
588  << (!getLangOpts().CPlusPlus1z
589  ? FixItHint::CreateReplacement(Tok.getLocation(), "class")
590  : FixItHint());
591  } else if (Next.isOneOf(tok::identifier, tok::comma, tok::greater,
592  tok::greatergreater, tok::ellipsis)) {
593  Diag(Tok.getLocation(), diag::err_class_on_template_template_param)
594  << (Replace ? FixItHint::CreateReplacement(Tok.getLocation(), "class")
595  : FixItHint::CreateInsertion(Tok.getLocation(), "class "));
596  } else
597  Diag(Tok.getLocation(), diag::err_class_on_template_template_param);
598 
599  if (Replace)
600  ConsumeToken();
601  }
602 
603  // Parse the ellipsis, if given.
604  SourceLocation EllipsisLoc;
605  if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
606  Diag(EllipsisLoc,
608  ? diag::warn_cxx98_compat_variadic_templates
609  : diag::ext_variadic_templates);
610 
611  // Get the identifier, if given.
612  SourceLocation NameLoc;
613  IdentifierInfo *ParamName = nullptr;
614  if (Tok.is(tok::identifier)) {
615  ParamName = Tok.getIdentifierInfo();
616  NameLoc = ConsumeToken();
617  } else if (Tok.isOneOf(tok::equal, tok::comma, tok::greater,
618  tok::greatergreater)) {
619  // Unnamed template parameter. Don't have to do anything here, just
620  // don't consume this token.
621  } else {
622  Diag(Tok.getLocation(), diag::err_expected) << tok::identifier;
623  return nullptr;
624  }
625 
626  // Recover from misplaced ellipsis.
627  bool AlreadyHasEllipsis = EllipsisLoc.isValid();
628  if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
629  DiagnoseMisplacedEllipsis(EllipsisLoc, NameLoc, AlreadyHasEllipsis, true);
630 
631  TemplateParameterList *ParamList =
633  TemplateLoc, LAngleLoc,
634  TemplateParams.data(),
635  TemplateParams.size(),
636  RAngleLoc);
637 
638  // Grab a default argument (if available).
639  // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
640  // we introduce the template parameter into the local scope.
641  SourceLocation EqualLoc;
642  ParsedTemplateArgument DefaultArg;
643  if (TryConsumeToken(tok::equal, EqualLoc)) {
644  DefaultArg = ParseTemplateTemplateArgument();
645  if (DefaultArg.isInvalid()) {
646  Diag(Tok.getLocation(),
647  diag::err_default_template_template_parameter_not_template);
648  SkipUntil(tok::comma, tok::greater, tok::greatergreater,
650  }
651  }
652 
653  return Actions.ActOnTemplateTemplateParameter(getCurScope(), TemplateLoc,
654  ParamList, EllipsisLoc,
655  ParamName, NameLoc, Depth,
656  Position, EqualLoc, DefaultArg);
657 }
658 
659 /// ParseNonTypeTemplateParameter - Handle the parsing of non-type
660 /// template parameters (e.g., in "template<int Size> class array;").
661 ///
662 /// template-parameter:
663 /// ...
664 /// parameter-declaration
665 Decl *
666 Parser::ParseNonTypeTemplateParameter(unsigned Depth, unsigned Position) {
667  // Parse the declaration-specifiers (i.e., the type).
668  // FIXME: The type should probably be restricted in some way... Not all
669  // declarators (parts of declarators?) are accepted for parameters.
670  DeclSpec DS(AttrFactory);
671  ParseDeclarationSpecifiers(DS);
672 
673  // Parse this as a typename.
675  ParseDeclarator(ParamDecl);
676  if (DS.getTypeSpecType() == DeclSpec::TST_unspecified) {
677  Diag(Tok.getLocation(), diag::err_expected_template_parameter);
678  return nullptr;
679  }
680 
681  // Recover from misplaced ellipsis.
682  SourceLocation EllipsisLoc;
683  if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
684  DiagnoseMisplacedEllipsisInDeclarator(EllipsisLoc, ParamDecl);
685 
686  // If there is a default value, parse it.
687  // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
688  // we introduce the template parameter into the local scope.
689  SourceLocation EqualLoc;
690  ExprResult DefaultArg;
691  if (TryConsumeToken(tok::equal, EqualLoc)) {
692  // C++ [temp.param]p15:
693  // When parsing a default template-argument for a non-type
694  // template-parameter, the first non-nested > is taken as the
695  // end of the template-parameter-list rather than a greater-than
696  // operator.
697  GreaterThanIsOperatorScope G(GreaterThanIsOperator, false);
699 
701  if (DefaultArg.isInvalid())
702  SkipUntil(tok::comma, tok::greater, StopAtSemi | StopBeforeMatch);
703  }
704 
705  // Create the parameter.
706  return Actions.ActOnNonTypeTemplateParameter(getCurScope(), ParamDecl,
707  Depth, Position, EqualLoc,
708  DefaultArg.get());
709 }
710 
711 void Parser::DiagnoseMisplacedEllipsis(SourceLocation EllipsisLoc,
712  SourceLocation CorrectLoc,
713  bool AlreadyHasEllipsis,
714  bool IdentifierHasName) {
715  FixItHint Insertion;
716  if (!AlreadyHasEllipsis)
717  Insertion = FixItHint::CreateInsertion(CorrectLoc, "...");
718  Diag(EllipsisLoc, diag::err_misplaced_ellipsis_in_declaration)
719  << FixItHint::CreateRemoval(EllipsisLoc) << Insertion
720  << !IdentifierHasName;
721 }
722 
723 void Parser::DiagnoseMisplacedEllipsisInDeclarator(SourceLocation EllipsisLoc,
724  Declarator &D) {
725  assert(EllipsisLoc.isValid());
726  bool AlreadyHasEllipsis = D.getEllipsisLoc().isValid();
727  if (!AlreadyHasEllipsis)
728  D.setEllipsisLoc(EllipsisLoc);
729  DiagnoseMisplacedEllipsis(EllipsisLoc, D.getIdentifierLoc(),
730  AlreadyHasEllipsis, D.hasName());
731 }
732 
733 /// \brief Parses a '>' at the end of a template list.
734 ///
735 /// If this function encounters '>>', '>>>', '>=', or '>>=', it tries
736 /// to determine if these tokens were supposed to be a '>' followed by
737 /// '>', '>>', '>=', or '>='. It emits an appropriate diagnostic if necessary.
738 ///
739 /// \param RAngleLoc the location of the consumed '>'.
740 ///
741 /// \param ConsumeLastToken if true, the '>' is consumed.
742 ///
743 /// \param ObjCGenericList if true, this is the '>' closing an Objective-C
744 /// type parameter or type argument list, rather than a C++ template parameter
745 /// or argument list.
746 ///
747 /// \returns true, if current token does not start with '>', false otherwise.
748 bool Parser::ParseGreaterThanInTemplateList(SourceLocation &RAngleLoc,
749  bool ConsumeLastToken,
750  bool ObjCGenericList) {
751  // What will be left once we've consumed the '>'.
752  tok::TokenKind RemainingToken;
753  const char *ReplacementStr = "> >";
754 
755  switch (Tok.getKind()) {
756  default:
757  Diag(Tok.getLocation(), diag::err_expected) << tok::greater;
758  return true;
759 
760  case tok::greater:
761  // Determine the location of the '>' token. Only consume this token
762  // if the caller asked us to.
763  RAngleLoc = Tok.getLocation();
764  if (ConsumeLastToken)
765  ConsumeToken();
766  return false;
767 
768  case tok::greatergreater:
769  RemainingToken = tok::greater;
770  break;
771 
772  case tok::greatergreatergreater:
773  RemainingToken = tok::greatergreater;
774  break;
775 
776  case tok::greaterequal:
777  RemainingToken = tok::equal;
778  ReplacementStr = "> =";
779  break;
780 
781  case tok::greatergreaterequal:
782  RemainingToken = tok::greaterequal;
783  break;
784  }
785 
786  // This template-id is terminated by a token which starts with a '>'. Outside
787  // C++11, this is now error recovery, and in C++11, this is error recovery if
788  // the token isn't '>>' or '>>>'.
789  // '>>>' is for CUDA, where this sequence of characters is parsed into
790  // tok::greatergreatergreater, rather than two separate tokens.
791  //
792  // We always allow this for Objective-C type parameter and type argument
793  // lists.
794  RAngleLoc = Tok.getLocation();
795  Token Next = NextToken();
796  if (!ObjCGenericList) {
797  // The source range of the '>>' or '>=' at the start of the token.
798  CharSourceRange ReplacementRange =
801  getLangOpts()));
802 
803  // A hint to put a space between the '>>'s. In order to make the hint as
804  // clear as possible, we include the characters either side of the space in
805  // the replacement, rather than just inserting a space at SecondCharLoc.
806  FixItHint Hint1 = FixItHint::CreateReplacement(ReplacementRange,
807  ReplacementStr);
808 
809  // A hint to put another space after the token, if it would otherwise be
810  // lexed differently.
811  FixItHint Hint2;
812  if ((RemainingToken == tok::greater ||
813  RemainingToken == tok::greatergreater) &&
814  (Next.isOneOf(tok::greater, tok::greatergreater,
815  tok::greatergreatergreater, tok::equal,
816  tok::greaterequal, tok::greatergreaterequal,
817  tok::equalequal)) &&
818  areTokensAdjacent(Tok, Next))
819  Hint2 = FixItHint::CreateInsertion(Next.getLocation(), " ");
820 
821  unsigned DiagId = diag::err_two_right_angle_brackets_need_space;
822  if (getLangOpts().CPlusPlus11 &&
823  (Tok.is(tok::greatergreater) || Tok.is(tok::greatergreatergreater)))
824  DiagId = diag::warn_cxx98_compat_two_right_angle_brackets;
825  else if (Tok.is(tok::greaterequal))
826  DiagId = diag::err_right_angle_bracket_equal_needs_space;
827  Diag(Tok.getLocation(), DiagId) << Hint1 << Hint2;
828  }
829 
830  // Strip the initial '>' from the token.
831  if (RemainingToken == tok::equal && Next.is(tok::equal) &&
832  areTokensAdjacent(Tok, Next)) {
833  // Join two adjacent '=' tokens into one, for cases like:
834  // void (*p)() = f<int>;
835  // return f<int>==p;
836  ConsumeToken();
837  Tok.setKind(tok::equalequal);
838  Tok.setLength(Tok.getLength() + 1);
839  } else {
840  Tok.setKind(RemainingToken);
841  Tok.setLength(Tok.getLength() - 1);
842  }
844  PP.getSourceManager(),
845  getLangOpts()));
846 
847  if (!ConsumeLastToken) {
848  // Since we're not supposed to consume the '>' token, we need to push
849  // this token and revert the current token back to the '>'.
850  PP.EnterToken(Tok);
851  Tok.setKind(tok::greater);
852  Tok.setLength(1);
853  Tok.setLocation(RAngleLoc);
854  }
855  return false;
856 }
857 
858 
859 /// \brief Parses a template-id that after the template name has
860 /// already been parsed.
861 ///
862 /// This routine takes care of parsing the enclosed template argument
863 /// list ('<' template-parameter-list [opt] '>') and placing the
864 /// results into a form that can be transferred to semantic analysis.
865 ///
866 /// \param Template the template declaration produced by isTemplateName
867 ///
868 /// \param TemplateNameLoc the source location of the template name
869 ///
870 /// \param SS if non-NULL, the nested-name-specifier preceding the
871 /// template name.
872 ///
873 /// \param ConsumeLastToken if true, then we will consume the last
874 /// token that forms the template-id. Otherwise, we will leave the
875 /// last token in the stream (e.g., so that it can be replaced with an
876 /// annotation token).
877 bool
878 Parser::ParseTemplateIdAfterTemplateName(TemplateTy Template,
879  SourceLocation TemplateNameLoc,
880  const CXXScopeSpec &SS,
881  bool ConsumeLastToken,
882  SourceLocation &LAngleLoc,
883  TemplateArgList &TemplateArgs,
884  SourceLocation &RAngleLoc) {
885  assert(Tok.is(tok::less) && "Must have already parsed the template-name");
886 
887  // Consume the '<'.
888  LAngleLoc = ConsumeToken();
889 
890  // Parse the optional template-argument-list.
891  bool Invalid = false;
892  {
893  GreaterThanIsOperatorScope G(GreaterThanIsOperator, false);
894  if (Tok.isNot(tok::greater) && Tok.isNot(tok::greatergreater))
895  Invalid = ParseTemplateArgumentList(TemplateArgs);
896 
897  if (Invalid) {
898  // Try to find the closing '>'.
899  if (ConsumeLastToken)
900  SkipUntil(tok::greater, StopAtSemi);
901  else
902  SkipUntil(tok::greater, StopAtSemi | StopBeforeMatch);
903  return true;
904  }
905  }
906 
907  return ParseGreaterThanInTemplateList(RAngleLoc, ConsumeLastToken,
908  /*ObjCGenericList=*/false);
909 }
910 
911 /// \brief Replace the tokens that form a simple-template-id with an
912 /// annotation token containing the complete template-id.
913 ///
914 /// The first token in the stream must be the name of a template that
915 /// is followed by a '<'. This routine will parse the complete
916 /// simple-template-id and replace the tokens with a single annotation
917 /// token with one of two different kinds: if the template-id names a
918 /// type (and \p AllowTypeAnnotation is true), the annotation token is
919 /// a type annotation that includes the optional nested-name-specifier
920 /// (\p SS). Otherwise, the annotation token is a template-id
921 /// annotation that does not include the optional
922 /// nested-name-specifier.
923 ///
924 /// \param Template the declaration of the template named by the first
925 /// token (an identifier), as returned from \c Action::isTemplateName().
926 ///
927 /// \param TNK the kind of template that \p Template
928 /// refers to, as returned from \c Action::isTemplateName().
929 ///
930 /// \param SS if non-NULL, the nested-name-specifier that precedes
931 /// this template name.
932 ///
933 /// \param TemplateKWLoc if valid, specifies that this template-id
934 /// annotation was preceded by the 'template' keyword and gives the
935 /// location of that keyword. If invalid (the default), then this
936 /// template-id was not preceded by a 'template' keyword.
937 ///
938 /// \param AllowTypeAnnotation if true (the default), then a
939 /// simple-template-id that refers to a class template, template
940 /// template parameter, or other template that produces a type will be
941 /// replaced with a type annotation token. Otherwise, the
942 /// simple-template-id is always replaced with a template-id
943 /// annotation token.
944 ///
945 /// If an unrecoverable parse error occurs and no annotation token can be
946 /// formed, this function returns true.
947 ///
948 bool Parser::AnnotateTemplateIdToken(TemplateTy Template, TemplateNameKind TNK,
949  CXXScopeSpec &SS,
950  SourceLocation TemplateKWLoc,
952  bool AllowTypeAnnotation) {
953  assert(getLangOpts().CPlusPlus && "Can only annotate template-ids in C++");
954  assert(Template && Tok.is(tok::less) &&
955  "Parser isn't at the beginning of a template-id");
956 
957  // Consume the template-name.
958  SourceLocation TemplateNameLoc = TemplateName.getSourceRange().getBegin();
959 
960  // Parse the enclosed template argument list.
961  SourceLocation LAngleLoc, RAngleLoc;
962  TemplateArgList TemplateArgs;
963  bool Invalid = ParseTemplateIdAfterTemplateName(Template,
964  TemplateNameLoc,
965  SS, false, LAngleLoc,
966  TemplateArgs,
967  RAngleLoc);
968 
969  if (Invalid) {
970  // If we failed to parse the template ID but skipped ahead to a >, we're not
971  // going to be able to form a token annotation. Eat the '>' if present.
972  TryConsumeToken(tok::greater);
973  return true;
974  }
975 
976  ASTTemplateArgsPtr TemplateArgsPtr(TemplateArgs);
977 
978  // Build the annotation token.
979  if (TNK == TNK_Type_template && AllowTypeAnnotation) {
981  = Actions.ActOnTemplateIdType(SS, TemplateKWLoc,
982  Template, TemplateNameLoc,
983  LAngleLoc, TemplateArgsPtr, RAngleLoc);
984  if (Type.isInvalid()) {
985  // If we failed to parse the template ID but skipped ahead to a >, we're not
986  // going to be able to form a token annotation. Eat the '>' if present.
987  TryConsumeToken(tok::greater);
988  return true;
989  }
990 
991  Tok.setKind(tok::annot_typename);
992  setTypeAnnotation(Tok, Type.get());
993  if (SS.isNotEmpty())
994  Tok.setLocation(SS.getBeginLoc());
995  else if (TemplateKWLoc.isValid())
996  Tok.setLocation(TemplateKWLoc);
997  else
998  Tok.setLocation(TemplateNameLoc);
999  } else {
1000  // Build a template-id annotation token that can be processed
1001  // later.
1002  Tok.setKind(tok::annot_template_id);
1003  TemplateIdAnnotation *TemplateId
1004  = TemplateIdAnnotation::Allocate(TemplateArgs.size(), TemplateIds);
1005  TemplateId->TemplateNameLoc = TemplateNameLoc;
1006  if (TemplateName.getKind() == UnqualifiedId::IK_Identifier) {
1007  TemplateId->Name = TemplateName.Identifier;
1008  TemplateId->Operator = OO_None;
1009  } else {
1010  TemplateId->Name = nullptr;
1011  TemplateId->Operator = TemplateName.OperatorFunctionId.Operator;
1012  }
1013  TemplateId->SS = SS;
1014  TemplateId->TemplateKWLoc = TemplateKWLoc;
1015  TemplateId->Template = Template;
1016  TemplateId->Kind = TNK;
1017  TemplateId->LAngleLoc = LAngleLoc;
1018  TemplateId->RAngleLoc = RAngleLoc;
1019  ParsedTemplateArgument *Args = TemplateId->getTemplateArgs();
1020  for (unsigned Arg = 0, ArgEnd = TemplateArgs.size(); Arg != ArgEnd; ++Arg)
1021  Args[Arg] = ParsedTemplateArgument(TemplateArgs[Arg]);
1022  Tok.setAnnotationValue(TemplateId);
1023  if (TemplateKWLoc.isValid())
1024  Tok.setLocation(TemplateKWLoc);
1025  else
1026  Tok.setLocation(TemplateNameLoc);
1027  }
1028 
1029  // Common fields for the annotation token
1030  Tok.setAnnotationEndLoc(RAngleLoc);
1031 
1032  // In case the tokens were cached, have Preprocessor replace them with the
1033  // annotation token.
1034  PP.AnnotateCachedTokens(Tok);
1035  return false;
1036 }
1037 
1038 /// \brief Replaces a template-id annotation token with a type
1039 /// annotation token.
1040 ///
1041 /// If there was a failure when forming the type from the template-id,
1042 /// a type annotation token will still be created, but will have a
1043 /// NULL type pointer to signify an error.
1044 void Parser::AnnotateTemplateIdTokenAsType() {
1045  assert(Tok.is(tok::annot_template_id) && "Requires template-id tokens");
1046 
1047  TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok);
1048  assert((TemplateId->Kind == TNK_Type_template ||
1049  TemplateId->Kind == TNK_Dependent_template_name) &&
1050  "Only works for type and dependent templates");
1051 
1052  ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
1053  TemplateId->NumArgs);
1054 
1055  TypeResult Type
1056  = Actions.ActOnTemplateIdType(TemplateId->SS,
1057  TemplateId->TemplateKWLoc,
1058  TemplateId->Template,
1059  TemplateId->TemplateNameLoc,
1060  TemplateId->LAngleLoc,
1061  TemplateArgsPtr,
1062  TemplateId->RAngleLoc);
1063  // Create the new "type" annotation token.
1064  Tok.setKind(tok::annot_typename);
1065  setTypeAnnotation(Tok, Type.isInvalid() ? ParsedType() : Type.get());
1066  if (TemplateId->SS.isNotEmpty()) // it was a C++ qualified type name.
1067  Tok.setLocation(TemplateId->SS.getBeginLoc());
1068  // End location stays the same
1069 
1070  // Replace the template-id annotation token, and possible the scope-specifier
1071  // that precedes it, with the typename annotation token.
1072  PP.AnnotateCachedTokens(Tok);
1073 }
1074 
1075 /// \brief Determine whether the given token can end a template argument.
1076 static bool isEndOfTemplateArgument(Token Tok) {
1077  return Tok.isOneOf(tok::comma, tok::greater, tok::greatergreater);
1078 }
1079 
1080 /// \brief Parse a C++ template template argument.
1081 ParsedTemplateArgument Parser::ParseTemplateTemplateArgument() {
1082  if (!Tok.is(tok::identifier) && !Tok.is(tok::coloncolon) &&
1083  !Tok.is(tok::annot_cxxscope))
1084  return ParsedTemplateArgument();
1085 
1086  // C++0x [temp.arg.template]p1:
1087  // A template-argument for a template template-parameter shall be the name
1088  // of a class template or an alias template, expressed as id-expression.
1089  //
1090  // We parse an id-expression that refers to a class template or alias
1091  // template. The grammar we parse is:
1092  //
1093  // nested-name-specifier[opt] template[opt] identifier ...[opt]
1094  //
1095  // followed by a token that terminates a template argument, such as ',',
1096  // '>', or (in some cases) '>>'.
1097  CXXScopeSpec SS; // nested-name-specifier, if present
1098  ParseOptionalCXXScopeSpecifier(SS, ParsedType(),
1099  /*EnteringContext=*/false);
1100 
1102  SourceLocation EllipsisLoc;
1103  if (SS.isSet() && Tok.is(tok::kw_template)) {
1104  // Parse the optional 'template' keyword following the
1105  // nested-name-specifier.
1106  SourceLocation TemplateKWLoc = ConsumeToken();
1107 
1108  if (Tok.is(tok::identifier)) {
1109  // We appear to have a dependent template name.
1110  UnqualifiedId Name;
1111  Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation());
1112  ConsumeToken(); // the identifier
1113 
1114  TryConsumeToken(tok::ellipsis, EllipsisLoc);
1115 
1116  // If the next token signals the end of a template argument,
1117  // then we have a dependent template name that could be a template
1118  // template argument.
1119  TemplateTy Template;
1120  if (isEndOfTemplateArgument(Tok) &&
1122  SS, TemplateKWLoc, Name,
1123  /*ObjectType=*/ ParsedType(),
1124  /*EnteringContext=*/false,
1125  Template))
1126  Result = ParsedTemplateArgument(SS, Template, Name.StartLocation);
1127  }
1128  } else if (Tok.is(tok::identifier)) {
1129  // We may have a (non-dependent) template name.
1130  TemplateTy Template;
1131  UnqualifiedId Name;
1132  Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation());
1133  ConsumeToken(); // the identifier
1134 
1135  TryConsumeToken(tok::ellipsis, EllipsisLoc);
1136 
1137  if (isEndOfTemplateArgument(Tok)) {
1138  bool MemberOfUnknownSpecialization;
1139  TemplateNameKind TNK = Actions.isTemplateName(getCurScope(), SS,
1140  /*hasTemplateKeyword=*/false,
1141  Name,
1142  /*ObjectType=*/ ParsedType(),
1143  /*EnteringContext=*/false,
1144  Template,
1145  MemberOfUnknownSpecialization);
1146  if (TNK == TNK_Dependent_template_name || TNK == TNK_Type_template) {
1147  // We have an id-expression that refers to a class template or
1148  // (C++0x) alias template.
1149  Result = ParsedTemplateArgument(SS, Template, Name.StartLocation);
1150  }
1151  }
1152  }
1153 
1154  // If this is a pack expansion, build it as such.
1155  if (EllipsisLoc.isValid() && !Result.isInvalid())
1156  Result = Actions.ActOnPackExpansion(Result, EllipsisLoc);
1157 
1158  return Result;
1159 }
1160 
1161 /// ParseTemplateArgument - Parse a C++ template argument (C++ [temp.names]).
1162 ///
1163 /// template-argument: [C++ 14.2]
1164 /// constant-expression
1165 /// type-id
1166 /// id-expression
1167 ParsedTemplateArgument Parser::ParseTemplateArgument() {
1168  // C++ [temp.arg]p2:
1169  // In a template-argument, an ambiguity between a type-id and an
1170  // expression is resolved to a type-id, regardless of the form of
1171  // the corresponding template-parameter.
1172  //
1173  // Therefore, we initially try to parse a type-id.
1174  if (isCXXTypeId(TypeIdAsTemplateArgument)) {
1175  SourceLocation Loc = Tok.getLocation();
1176  TypeResult TypeArg = ParseTypeName(/*Range=*/nullptr,
1178  if (TypeArg.isInvalid())
1179  return ParsedTemplateArgument();
1180 
1182  TypeArg.get().getAsOpaquePtr(),
1183  Loc);
1184  }
1185 
1186  // Try to parse a template template argument.
1187  {
1188  TentativeParsingAction TPA(*this);
1189 
1190  ParsedTemplateArgument TemplateTemplateArgument
1191  = ParseTemplateTemplateArgument();
1192  if (!TemplateTemplateArgument.isInvalid()) {
1193  TPA.Commit();
1194  return TemplateTemplateArgument;
1195  }
1196 
1197  // Revert this tentative parse to parse a non-type template argument.
1198  TPA.Revert();
1199  }
1200 
1201  // Parse a non-type template argument.
1202  SourceLocation Loc = Tok.getLocation();
1204  if (ExprArg.isInvalid() || !ExprArg.get())
1205  return ParsedTemplateArgument();
1206 
1208  ExprArg.get(), Loc);
1209 }
1210 
1211 /// \brief Determine whether the current tokens can only be parsed as a
1212 /// template argument list (starting with the '<') and never as a '<'
1213 /// expression.
1214 bool Parser::IsTemplateArgumentList(unsigned Skip) {
1215  struct AlwaysRevertAction : TentativeParsingAction {
1216  AlwaysRevertAction(Parser &P) : TentativeParsingAction(P) { }
1217  ~AlwaysRevertAction() { Revert(); }
1218  } Tentative(*this);
1219 
1220  while (Skip) {
1221  ConsumeToken();
1222  --Skip;
1223  }
1224 
1225  // '<'
1226  if (!TryConsumeToken(tok::less))
1227  return false;
1228 
1229  // An empty template argument list.
1230  if (Tok.is(tok::greater))
1231  return true;
1232 
1233  // See whether we have declaration specifiers, which indicate a type.
1234  while (isCXXDeclarationSpecifier() == TPResult::True)
1235  ConsumeToken();
1236 
1237  // If we have a '>' or a ',' then this is a template argument list.
1238  return Tok.isOneOf(tok::greater, tok::comma);
1239 }
1240 
1241 /// ParseTemplateArgumentList - Parse a C++ template-argument-list
1242 /// (C++ [temp.names]). Returns true if there was an error.
1243 ///
1244 /// template-argument-list: [C++ 14.2]
1245 /// template-argument
1246 /// template-argument-list ',' template-argument
1247 bool
1248 Parser::ParseTemplateArgumentList(TemplateArgList &TemplateArgs) {
1249  // Template argument lists are constant-evaluation contexts.
1251  ColonProtectionRAIIObject ColonProtection(*this, false);
1252 
1253  do {
1254  ParsedTemplateArgument Arg = ParseTemplateArgument();
1255  SourceLocation EllipsisLoc;
1256  if (TryConsumeToken(tok::ellipsis, EllipsisLoc))
1257  Arg = Actions.ActOnPackExpansion(Arg, EllipsisLoc);
1258 
1259  if (Arg.isInvalid()) {
1260  SkipUntil(tok::comma, tok::greater, StopAtSemi | StopBeforeMatch);
1261  return true;
1262  }
1263 
1264  // Save this template argument.
1265  TemplateArgs.push_back(Arg);
1266 
1267  // If the next token is a comma, consume it and keep reading
1268  // arguments.
1269  } while (TryConsumeToken(tok::comma));
1270 
1271  return false;
1272 }
1273 
1274 /// \brief Parse a C++ explicit template instantiation
1275 /// (C++ [temp.explicit]).
1276 ///
1277 /// explicit-instantiation:
1278 /// 'extern' [opt] 'template' declaration
1279 ///
1280 /// Note that the 'extern' is a GNU extension and C++11 feature.
1281 Decl *Parser::ParseExplicitInstantiation(unsigned Context,
1282  SourceLocation ExternLoc,
1283  SourceLocation TemplateLoc,
1284  SourceLocation &DeclEnd,
1285  AccessSpecifier AS) {
1286  // This isn't really required here.
1288  ParsingTemplateParams(*this, ParsingDeclRAIIObject::NoParent);
1289 
1290  return ParseSingleDeclarationAfterTemplate(Context,
1291  ParsedTemplateInfo(ExternLoc,
1292  TemplateLoc),
1293  ParsingTemplateParams,
1294  DeclEnd, AS);
1295 }
1296 
1297 SourceRange Parser::ParsedTemplateInfo::getSourceRange() const {
1298  if (TemplateParams)
1299  return getTemplateParamsRange(TemplateParams->data(),
1300  TemplateParams->size());
1301 
1302  SourceRange R(TemplateLoc);
1303  if (ExternLoc.isValid())
1304  R.setBegin(ExternLoc);
1305  return R;
1306 }
1307 
1308 void Parser::LateTemplateParserCallback(void *P, LateParsedTemplate &LPT) {
1309  ((Parser *)P)->ParseLateTemplatedFuncDef(LPT);
1310 }
1311 
1312 /// \brief Late parse a C++ function template in Microsoft mode.
1313 void Parser::ParseLateTemplatedFuncDef(LateParsedTemplate &LPT) {
1314  if (!LPT.D)
1315  return;
1316 
1317  // Get the FunctionDecl.
1318  FunctionDecl *FunD = LPT.D->getAsFunction();
1319  // Track template parameter depth.
1320  TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth);
1321 
1322  // To restore the context after late parsing.
1323  Sema::ContextRAII GlobalSavedContext(
1324  Actions, Actions.Context.getTranslationUnitDecl());
1325 
1326  SmallVector<ParseScope*, 4> TemplateParamScopeStack;
1327 
1328  // Get the list of DeclContexts to reenter.
1329  SmallVector<DeclContext*, 4> DeclContextsToReenter;
1330  DeclContext *DD = FunD;
1331  while (DD && !DD->isTranslationUnit()) {
1332  DeclContextsToReenter.push_back(DD);
1333  DD = DD->getLexicalParent();
1334  }
1335 
1336  // Reenter template scopes from outermost to innermost.
1338  DeclContextsToReenter.rbegin();
1339  for (; II != DeclContextsToReenter.rend(); ++II) {
1340  TemplateParamScopeStack.push_back(new ParseScope(this,
1342  unsigned NumParamLists =
1343  Actions.ActOnReenterTemplateScope(getCurScope(), cast<Decl>(*II));
1344  CurTemplateDepthTracker.addDepth(NumParamLists);
1345  if (*II != FunD) {
1346  TemplateParamScopeStack.push_back(new ParseScope(this, Scope::DeclScope));
1347  Actions.PushDeclContext(Actions.getCurScope(), *II);
1348  }
1349  }
1350 
1351  assert(!LPT.Toks.empty() && "Empty body!");
1352 
1353  // Append the current token at the end of the new token stream so that it
1354  // doesn't get lost.
1355  LPT.Toks.push_back(Tok);
1356  PP.EnterTokenStream(LPT.Toks.data(), LPT.Toks.size(), true, false);
1357 
1358  // Consume the previously pushed token.
1359  ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);
1360  assert(Tok.isOneOf(tok::l_brace, tok::colon, tok::kw_try) &&
1361  "Inline method not starting with '{', ':' or 'try'");
1362 
1363  // Parse the method body. Function body parsing code is similar enough
1364  // to be re-used for method bodies as well.
1365  ParseScope FnScope(this, Scope::FnScope|Scope::DeclScope);
1366 
1367  // Recreate the containing function DeclContext.
1368  Sema::ContextRAII FunctionSavedContext(Actions,
1369  Actions.getContainingDC(FunD));
1370 
1371  Actions.ActOnStartOfFunctionDef(getCurScope(), FunD);
1372 
1373  if (Tok.is(tok::kw_try)) {
1374  ParseFunctionTryBlock(LPT.D, FnScope);
1375  } else {
1376  if (Tok.is(tok::colon))
1377  ParseConstructorInitializer(LPT.D);
1378  else
1379  Actions.ActOnDefaultCtorInitializers(LPT.D);
1380 
1381  if (Tok.is(tok::l_brace)) {
1382  assert((!isa<FunctionTemplateDecl>(LPT.D) ||
1383  cast<FunctionTemplateDecl>(LPT.D)
1384  ->getTemplateParameters()
1385  ->getDepth() == TemplateParameterDepth - 1) &&
1386  "TemplateParameterDepth should be greater than the depth of "
1387  "current template being instantiated!");
1388  ParseFunctionStatementBody(LPT.D, FnScope);
1389  Actions.UnmarkAsLateParsedTemplate(FunD);
1390  } else
1391  Actions.ActOnFinishFunctionBody(LPT.D, nullptr);
1392  }
1393 
1394  // Exit scopes.
1395  FnScope.Exit();
1397  TemplateParamScopeStack.rbegin();
1398  for (; I != TemplateParamScopeStack.rend(); ++I)
1399  delete *I;
1400 }
1401 
1402 /// \brief Lex a delayed template function for late parsing.
1403 void Parser::LexTemplateFunctionForLateParsing(CachedTokens &Toks) {
1404  tok::TokenKind kind = Tok.getKind();
1405  if (!ConsumeAndStoreFunctionPrologue(Toks)) {
1406  // Consume everything up to (and including) the matching right brace.
1407  ConsumeAndStoreUntil(tok::r_brace, Toks, /*StopAtSemi=*/false);
1408  }
1409 
1410  // If we're in a function-try-block, we need to store all the catch blocks.
1411  if (kind == tok::kw_try) {
1412  while (Tok.is(tok::kw_catch)) {
1413  ConsumeAndStoreUntil(tok::l_brace, Toks, /*StopAtSemi=*/false);
1414  ConsumeAndStoreUntil(tok::r_brace, Toks, /*StopAtSemi=*/false);
1415  }
1416  }
1417 }
SourceManager & getSourceManager() const
Definition: Preprocessor.h:682
Defines the clang::ASTContext interface.
IdKind getKind() const
Determine what kind of name we have.
Definition: DeclSpec.h:966
int Position
Scope * getCurScope() const
Retrieve the parser's current scope.
Definition: Sema.h:8979
bool isInvalid() const
Definition: Ownership.h:159
SourceRange getSourceRange() const LLVM_READONLY
Return the source range that covers this unqualified-id.
Definition: DeclSpec.h:1072
SourceLocation StartLocation
The location of the first token that describes this unqualified-id, which will be the location of the...
Definition: DeclSpec.h:943
IdentifierInfo * Name
FIXME: Temporarily stores the name of a specialization.
const LangOptions & getLangOpts() const
Definition: Parse/Parser.h:243
IdentifierInfo * Identifier
When Kind == IK_Identifier, the parsed identifier, or when Kind == IK_UserLiteralId, the identifier suffix.
Definition: DeclSpec.h:916
RAII object used to inform the actions that we're currently parsing a declaration. This is active when parsing a variable's initializer, but not when parsing the body of a class or function definition.
Defines the C++ template declaration subclasses.
PtrTy get() const
Definition: Ownership.h:163
This indicates that the scope corresponds to a function, which means that labels are set here...
Definition: Scope.h:45
AccessSpecifier
A C++ access specifier (public, private, protected), plus the special value "none" which means differ...
Definition: Specifiers.h:83
TemplateNameKind Kind
The kind of template that Template refers to.
void ActOnDefaultCtorInitializers(Decl *CDtorDecl)
RAII object that enters a new expression evaluation context.
Definition: Sema.h:9016
void EnterToken(const Token &Tok)
Enters a token in the token stream to be lexed next.
Information about one declarator, including the parsed type information and the identifier.
Definition: DeclSpec.h:1572
Stores a list of template parameters for a TemplateDecl and its derived classes.
Definition: DeclTemplate.h:46
TemplateParameterList * ActOnTemplateParameterList(unsigned Depth, SourceLocation ExportLoc, SourceLocation TemplateLoc, SourceLocation LAngleLoc, Decl **Params, unsigned NumParams, SourceLocation RAngleLoc)
friend class ObjCDeclContextSwitch
Definition: Parse/Parser.h:60
bool SkipUntil(tok::TokenKind T, SkipUntilFlags Flags=static_cast< SkipUntilFlags >(0))
Definition: Parse/Parser.h:861
Information about a template-id annotation token.
const Token & NextToken()
Definition: Parse/Parser.h:546
SourceLocation getLocForEndOfToken(SourceLocation Loc, unsigned Offset=0)
Computes the source location just past the end of the token at this source location.
bool TryConsumeToken(tok::TokenKind Expected)
Definition: Parse/Parser.h:292
OpaquePtr< QualType > ParsedType
Definition: Ownership.h:233
Decl * ActOnNonTypeTemplateParameter(Scope *S, Declarator &D, unsigned Depth, unsigned Position, SourceLocation EqualLoc, Expr *DefaultArg)
OverloadedOperatorKind Operator
The kind of overloaded operator.
Definition: DeclSpec.h:899
TypeResult ActOnTemplateIdType(CXXScopeSpec &SS, SourceLocation TemplateKWLoc, TemplateTy Template, SourceLocation TemplateLoc, SourceLocation LAngleLoc, ASTTemplateArgsPtr TemplateArgs, SourceLocation RAngleLoc, bool IsCtorOrDtorName=false)
struct OFI OperatorFunctionId
When Kind == IK_OperatorFunctionId, the overloaded operator that we parsed.
Definition: DeclSpec.h:920
bool isTranslationUnit() const
Definition: DeclBase.h:1243
CachedTokens Toks
Definition: Sema.h:9050
A non-type template parameter, stored as an expression.
void setKind(tok::TokenKind K)
Definition: Token.h:91
Represents a C++ unqualified-id that has been parsed.
Definition: DeclSpec.h:869
SourceLocation getLocWithOffset(int Offset) const
Return a source location with the specified offset from this SourceLocation.
ParsedTemplateArgument * getTemplateArgs()
Retrieves a pointer to the template arguments.
Represents a C++ nested-name-specifier or a global scope specifier.
Definition: DeclSpec.h:68
tok::TokenKind getKind() const
Definition: Token.h:90
Decl * ActOnFinishFunctionBody(Decl *Decl, Stmt *Body)
Definition: SemaDecl.cpp:10726
static SourceLocation AdvanceToTokenCharacter(SourceLocation TokStart, unsigned Character, const SourceManager &SM, const LangOptions &LangOpts)
Definition: Lexer.cpp:700
Decl * ActOnTypeParameter(Scope *S, bool Typename, SourceLocation EllipsisLoc, SourceLocation KeyLoc, IdentifierInfo *ParamName, SourceLocation ParamNameLoc, unsigned Depth, unsigned Position, SourceLocation EqualLoc, ParsedType DefaultArg)
AnnotatingParser & P
Decl * ActOnStartOfFunctionDef(Scope *S, Declarator &D)
Definition: SemaDecl.cpp:10373
A class for parsing a declarator.
ASTContext * Context
TypeResult ParseTypeName(SourceRange *Range=nullptr, Declarator::TheContext Context=Declarator::TypeNameContext, AccessSpecifier AS=AS_none, Decl **OwnedType=nullptr, ParsedAttributes *Attrs=nullptr)
Definition: ParseDecl.cpp:41
int * Depth
DeclContext * getLexicalParent()
Definition: DeclBase.h:1190
void setAnnotationValue(void *val)
Definition: Token.h:228
Represents a character-granular source range.
void AnnotateCachedTokens(const Token &Tok)
This file defines the classes used to store parsed information about declaration-specifiers and decla...
void SkipMalformedDecl()
Definition: ParseDecl.cpp:1617
TranslationUnitDecl * getTranslationUnitDecl() const
Definition: ASTContext.h:812
OpaquePtr< TemplateName > TemplateTy
Definition: Parse/Parser.h:260
static bool isEndOfTemplateArgument(Token Tok)
Determine whether the given token can end a template argument.
Represents a C++ template name within the type system.
Definition: TemplateName.h:175
SourceLocation getLocation() const
Return a source location identifier for the specified offset in the current file. ...
Definition: Token.h:124
TemplateNameKind
Specifies the kind of template name that an identifier refers to. Be careful when changing this: this...
Definition: TemplateKinds.h:21
bool isNot(tok::TokenKind K) const
Definition: Token.h:96
void setEllipsisLoc(SourceLocation EL)
Definition: DeclSpec.h:2176
DeclContext * getContainingDC(DeclContext *DC)
Definition: SemaDecl.cpp:1034
TemplateNameKind isTemplateName(Scope *S, CXXScopeSpec &SS, bool hasTemplateKeyword, UnqualifiedId &Name, ParsedType ObjectType, bool EnteringContext, TemplateTy &Template, bool &MemberOfUnknownSpecialization)
The result type of a method or function.
ParsedTemplateArgument ActOnPackExpansion(const ParsedTemplateArgument &Arg, SourceLocation EllipsisLoc)
Invoked when parsing a template argument followed by an ellipsis, which creates a pack expansion...
RAII object that makes '>' behave either as an operator or as the closing angle bracket for a temp...
static CharSourceRange getCharRange(SourceRange R)
A class for parsing a DeclSpec.
Represents the parsed form of a C++ template argument.
SmallVectorImpl< AnnotatedLine * >::const_iterator Next
FunctionDecl * getAsFunction() LLVM_READONLY
Returns the function itself, or the templated function if this is a function template.
Definition: DeclBase.cpp:172
Encodes a location in the source. The SourceManager can decode this to get at the full include stack...
void setLength(unsigned Len)
Definition: Token.h:133
bool isValid() const
Return true if this is a valid SourceLocation object.
void setAnnotationEndLoc(SourceLocation L)
Definition: Token.h:142
Scope * getCurScope() const
Definition: Parse/Parser.h:250
void EnterTokenStream(const Token *Toks, unsigned NumToks, bool DisableMacroExpansion, bool OwnsTokens)
Add a "macro" context to the top of the include stack, which will cause the lexer to start returning ...
TokenKind
Provides a simple uniform namespace for tokens from all C languages.
Definition: TokenKinds.h:25
SourceLocation getBegin() const
SourceLocation getBeginLoc() const
Definition: DeclSpec.h:77
bool is(tok::TokenKind K) const
Definition: Token.h:95
A template type parameter, stored as a type.
void UnmarkAsLateParsedTemplate(FunctionDecl *FD)
Decl * ActOnTemplateTemplateParameter(Scope *S, SourceLocation TmpLoc, TemplateParameterList *Params, SourceLocation EllipsisLoc, IdentifierInfo *ParamName, SourceLocation ParamNameLoc, unsigned Depth, unsigned Position, SourceLocation EqualLoc, ParsedTemplateArgument DefaultArg)
CXXScopeSpec SS
The nested-name-specifier that precedes the template name.
static FixItHint CreateRemoval(CharSourceRange RemoveRange)
Create a code modification hint that removes the given source range.
Definition: Diagnostic.h:104
This is a scope that corresponds to the template parameters of a C++ template. Template parameter sco...
Definition: Scope.h:75
ExprResult ParseConstraintExpression()
Parse a constraint-expression.
Definition: ParseExpr.cpp:214
void PushDeclContext(Scope *S, DeclContext *DC)
Set the current declaration context until it gets popped.
Definition: SemaDecl.cpp:1070
bool hasName() const
Definition: DeclSpec.h:1911
static const TST TST_unspecified
Definition: DeclSpec.h:277
Not an overloaded operator.
Definition: OperatorKinds.h:23
bool isNotEmpty() const
A scope specifier is present, but may be valid or invalid.
Definition: DeclSpec.h:196
bool isOneOf(tok::TokenKind K1, tok::TokenKind K2) const
Definition: Token.h:97
DiagnosticBuilder Diag(SourceLocation Loc, unsigned DiagID)
OverloadedOperatorKind Operator
FIXME: Temporarily stores the overloaded operator kind.
bool isInvalid() const
Determine whether the given template argument is invalid.
SourceRange getTemplateParamsRange(TemplateParameterList const *const *Params, unsigned NumParams)
Retrieves the range of the given template parameter lists.
ExprResult ParseAssignmentExpression(TypeCastState isTypeCast=NotTypeCast)
Parse an expr that doesn't include (top-level) commas.
Definition: ParseExpr.cpp:157
static FixItHint CreateInsertion(SourceLocation InsertionLoc, StringRef Code, bool BeforePreviousInsertions=false)
Create a code modification hint that inserts the given code string at a specific location.
Definition: Diagnostic.h:78
A template-id, e.g., f<int>.
Definition: DeclSpec.h:892
SmallVector< TemplateParameterList *, 4 > TemplateParameterLists
Definition: Parse/Parser.h:262
bool isUsable() const
Definition: Ownership.h:160
This is a scope that can contain a declaration. Some scopes just contain loop constructs but don't co...
Definition: Scope.h:57
Decl * ParsedFreeStandingDeclSpec(Scope *S, AccessSpecifier AS, DeclSpec &DS)
Definition: SemaDecl.cpp:3540
ExprResult ParseConstantExpression(TypeCastState isTypeCast=NotTypeCast)
Definition: ParseExpr.cpp:195
TemplateNameKind ActOnDependentTemplateName(Scope *S, CXXScopeSpec &SS, SourceLocation TemplateKWLoc, UnqualifiedId &Name, ParsedType ObjectType, bool EnteringContext, TemplateTy &Template)
Form a dependent template name.
Captures information about "declaration specifiers".
Definition: DeclSpec.h:233
SourceLocation getIdentifierLoc() const
Definition: DeclSpec.h:1921
SourceLocation ConsumeToken()
Definition: Parse/Parser.h:284
static TemplateIdAnnotation * Allocate(unsigned NumArgs, SmallVectorImpl< TemplateIdAnnotation * > &List)
Creates a new TemplateIdAnnotation with NumArgs arguments and appends it to List. ...
Decl * D
The template function declaration to be late parsed.
Definition: Sema.h:9052
The current context is "potentially evaluated" in C++11 terms, but the expression is evaluated at com...
Definition: Sema.h:776
ExprResult CorrectDelayedTyposInExpr(Expr *E, VarDecl *InitDecl=nullptr, llvm::function_ref< ExprResult(Expr *)> Filter=[](Expr *E) -> ExprResult{return E;})
Process any TypoExprs in the given Expr and its children, generating diagnostics as appropriate and r...
unsigned kind
All of the diagnostics that can be emitted by the frontend.
Definition: DiagnosticIDs.h:43
static FixItHint CreateReplacement(CharSourceRange RemoveRange, StringRef Code)
Create a code modification hint that replaces the given source range with the given code string...
Definition: Diagnostic.h:115
bool isSet() const
Definition: DeclSpec.h:214
unsigned getLength() const
Definition: Token.h:127
The current expression and its subexpressions occur within an unevaluated operand (C++11 [expr]p7)...
Definition: Sema.h:766
Contains a late templated function. Will be parsed at the end of the translation unit, used by Sema & Parser.
Definition: Sema.h:9049
Annotates a diagnostic with some code that should be inserted, removed, or replaced to fix the proble...
Definition: Diagnostic.h:52
void setLocation(SourceLocation L)
Definition: Token.h:132
A trivial tuple used to represent a source range.
ASTContext & Context
Definition: Sema.h:295
void setIdentifier(const IdentifierInfo *Id, SourceLocation IdLoc)
Specify that this unqualified-id was parsed as an identifier.
Definition: DeclSpec.h:973
Stop skipping at specified token, but don't skip the token itself.
Definition: Parse/Parser.h:843
SourceLocation getEllipsisLoc() const
Definition: DeclSpec.h:2175
unsigned ActOnReenterTemplateScope(Scope *S, Decl *Template)
A RAII object to temporarily push a declaration context.
Definition: Sema.h:601
IdentifierInfo * getIdentifierInfo() const
Definition: Token.h:177