ParseTemplate.cpp revision 4985429d6f0dddbe168ec0ed4de029d56294e644 
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/DeclTemplate.h"
18#include "clang/Parse/ParseDiagnostic.h"
19#include "clang/Sema/DeclSpec.h"
20#include "clang/Sema/ParsedTemplate.h"
21#include "clang/Sema/Scope.h"
22using namespace clang;
23
24/// \brief Parse a template declaration, explicit instantiation, or
25/// explicit specialization.
26Decl *
27Parser::ParseDeclarationStartingWithTemplate(unsigned Context,
28                                             SourceLocation &DeclEnd,
29                                             AccessSpecifier AS,
30                                             AttributeList *AccessAttrs) {
31  ObjCDeclContextSwitch ObjCDC(*this);
32
33  if (Tok.is(tok::kw_template) && NextToken().isNot(tok::less)) {
34    return ParseExplicitInstantiation(Context,
35                                      SourceLocation(), ConsumeToken(),
36                                      DeclEnd, AS);
37  }
38  return ParseTemplateDeclarationOrSpecialization(Context, DeclEnd, AS,
39                                                  AccessAttrs);
40}
41
42
43
44/// \brief Parse a template declaration or an explicit specialization.
45///
46/// Template declarations include one or more template parameter lists
47/// and either the function or class template declaration. Explicit
48/// specializations contain one or more 'template < >' prefixes
49/// followed by a (possibly templated) declaration. Since the
50/// syntactic form of both features is nearly identical, we parse all
51/// of the template headers together and let semantic analysis sort
52/// the declarations from the explicit specializations.
53///
54///       template-declaration: [C++ temp]
55///         'export'[opt] 'template' '<' template-parameter-list '>' declaration
56///
57///       explicit-specialization: [ C++ temp.expl.spec]
58///         'template' '<' '>' declaration
59Decl *
60Parser::ParseTemplateDeclarationOrSpecialization(unsigned Context,
61                                                 SourceLocation &DeclEnd,
62                                                 AccessSpecifier AS,
63                                                 AttributeList *AccessAttrs) {
64  assert((Tok.is(tok::kw_export) || Tok.is(tok::kw_template)) &&
65         "Token does not start a template declaration.");
66
67  // Enter template-parameter scope.
68  ParseScope TemplateParmScope(this, Scope::TemplateParamScope);
69
70  // Tell the action that names should be checked in the context of
71  // the declaration to come.
72  ParsingDeclRAIIObject
73    ParsingTemplateParams(*this, ParsingDeclRAIIObject::NoParent);
74
75  // Parse multiple levels of template headers within this template
76  // parameter scope, e.g.,
77  //
78  //   template<typename T>
79  //     template<typename U>
80  //       class A<T>::B { ... };
81  //
82  // We parse multiple levels non-recursively so that we can build a
83  // single data structure containing all of the template parameter
84  // lists to easily differentiate between the case above and:
85  //
86  //   template<typename T>
87  //   class A {
88  //     template<typename U> class B;
89  //   };
90  //
91  // In the first case, the action for declaring A<T>::B receives
92  // both template parameter lists. In the second case, the action for
93  // defining A<T>::B receives just the inner template parameter list
94  // (and retrieves the outer template parameter list from its
95  // context).
96  bool isSpecialization = true;
97  bool LastParamListWasEmpty = false;
98  TemplateParameterLists ParamLists;
99  TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth);
100
101  do {
102    // Consume the 'export', if any.
103    SourceLocation ExportLoc;
104    if (Tok.is(tok::kw_export)) {
105      ExportLoc = ConsumeToken();
106    }
107
108    // Consume the 'template', which should be here.
109    SourceLocation TemplateLoc;
110    if (Tok.is(tok::kw_template)) {
111      TemplateLoc = ConsumeToken();
112    } else {
113      Diag(Tok.getLocation(), diag::err_expected_template);
114      return 0;
115    }
116
117    // Parse the '<' template-parameter-list '>'
118    SourceLocation LAngleLoc, RAngleLoc;
119    SmallVector<Decl*, 4> TemplateParams;
120    if (ParseTemplateParameters(CurTemplateDepthTracker.getDepth(),
121                                TemplateParams, LAngleLoc, RAngleLoc)) {
122      // Skip until the semi-colon or a }.
123      SkipUntil(tok::r_brace, true, true);
124      if (Tok.is(tok::semi))
125        ConsumeToken();
126      return 0;
127    }
128
129    ParamLists.push_back(
130      Actions.ActOnTemplateParameterList(CurTemplateDepthTracker.getDepth(),
131                                         ExportLoc,
132                                         TemplateLoc, LAngleLoc,
133                                         TemplateParams.data(),
134                                         TemplateParams.size(), RAngleLoc));
135
136    if (!TemplateParams.empty()) {
137      isSpecialization = false;
138      ++CurTemplateDepthTracker;
139    } else {
140      LastParamListWasEmpty = true;
141    }
142  } while (Tok.is(tok::kw_export) || Tok.is(tok::kw_template));
143
144  // Parse the actual template declaration.
145  return ParseSingleDeclarationAfterTemplate(Context,
146                                             ParsedTemplateInfo(&ParamLists,
147                                                             isSpecialization,
148                                                         LastParamListWasEmpty),
149                                             ParsingTemplateParams,
150                                             DeclEnd, AS, AccessAttrs);
151}
152
153/// \brief Parse a single declaration that declares a template,
154/// template specialization, or explicit instantiation of a template.
155///
156/// \param DeclEnd will receive the source location of the last token
157/// within this declaration.
158///
159/// \param AS the access specifier associated with this
160/// declaration. Will be AS_none for namespace-scope declarations.
161///
162/// \returns the new declaration.
163Decl *
164Parser::ParseSingleDeclarationAfterTemplate(
165                                       unsigned Context,
166                                       const ParsedTemplateInfo &TemplateInfo,
167                                       ParsingDeclRAIIObject &DiagsFromTParams,
168                                       SourceLocation &DeclEnd,
169                                       AccessSpecifier AS,
170                                       AttributeList *AccessAttrs) {
171  assert(TemplateInfo.Kind != ParsedTemplateInfo::NonTemplate &&
172         "Template information required");
173
174  if (Context == Declarator::MemberContext) {
175    // We are parsing a member template.
176    ParseCXXClassMemberDeclaration(AS, AccessAttrs, TemplateInfo,
177                                   &DiagsFromTParams);
178    return 0;
179  }
180
181  ParsedAttributesWithRange prefixAttrs(AttrFactory);
182  MaybeParseCXX11Attributes(prefixAttrs);
183
184  if (Tok.is(tok::kw_using))
185    return ParseUsingDirectiveOrDeclaration(Context, TemplateInfo, DeclEnd,
186                                            prefixAttrs);
187
188  // Parse the declaration specifiers, stealing any diagnostics from
189  // the template parameters.
190  ParsingDeclSpec DS(*this, &DiagsFromTParams);
191
192  ParseDeclarationSpecifiers(DS, TemplateInfo, AS,
193                             getDeclSpecContextFromDeclaratorContext(Context));
194
195  if (Tok.is(tok::semi)) {
196    ProhibitAttributes(prefixAttrs);
197    DeclEnd = ConsumeToken();
198    Decl *Decl = Actions.ParsedFreeStandingDeclSpec(
199        getCurScope(), AS, DS,
200        TemplateInfo.TemplateParams ? *TemplateInfo.TemplateParams
201                                    : MultiTemplateParamsArg(),
202        TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation);
203    DS.complete(Decl);
204    return Decl;
205  }
206
207  // Move the attributes from the prefix into the DS.
208  if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation)
209    ProhibitAttributes(prefixAttrs);
210  else
211    DS.takeAttributesFrom(prefixAttrs);
212
213  // Parse the declarator.
214  ParsingDeclarator DeclaratorInfo(*this, DS, (Declarator::TheContext)Context);
215  ParseDeclarator(DeclaratorInfo);
216  // Error parsing the declarator?
217  if (!DeclaratorInfo.hasName()) {
218    // If so, skip until the semi-colon or a }.
219    SkipUntil(tok::r_brace, true, true);
220    if (Tok.is(tok::semi))
221      ConsumeToken();
222    return 0;
223  }
224
225  LateParsedAttrList LateParsedAttrs(true);
226  if (DeclaratorInfo.isFunctionDeclarator())
227    MaybeParseGNUAttributes(DeclaratorInfo, &LateParsedAttrs);
228
229  if (DeclaratorInfo.isFunctionDeclarator() &&
230      isStartOfFunctionDefinition(DeclaratorInfo)) {
231    if (DS.getStorageClassSpec() == DeclSpec::SCS_typedef) {
232      // Recover by ignoring the 'typedef'. This was probably supposed to be
233      // the 'typename' keyword, which we should have already suggested adding
234      // if it's appropriate.
235      Diag(DS.getStorageClassSpecLoc(), diag::err_function_declared_typedef)
236        << FixItHint::CreateRemoval(DS.getStorageClassSpecLoc());
237      DS.ClearStorageClassSpecs();
238    }
239
240    if (TemplateInfo.Kind == ParsedTemplateInfo::ExplicitInstantiation) {
241      if (DeclaratorInfo.getName().getKind() != UnqualifiedId::IK_TemplateId) {
242        // If the declarator-id is not a template-id, issue a diagnostic and
243        // recover by ignoring the 'template' keyword.
244        Diag(Tok, diag::err_template_defn_explicit_instantiation) << 0;
245	return ParseFunctionDefinition(DeclaratorInfo, ParsedTemplateInfo(),
246				       &LateParsedAttrs);
247      } else {
248        SourceLocation LAngleLoc
249          = PP.getLocForEndOfToken(TemplateInfo.TemplateLoc);
250        Diag(DeclaratorInfo.getIdentifierLoc(),
251             diag::err_explicit_instantiation_with_definition)
252          << SourceRange(TemplateInfo.TemplateLoc)
253          << FixItHint::CreateInsertion(LAngleLoc, "<>");
254
255        // Recover as if it were an explicit specialization.
256        TemplateParameterLists FakedParamLists;
257        FakedParamLists.push_back(
258	     Actions.ActOnTemplateParameterList(0, SourceLocation(),
259					        TemplateInfo.TemplateLoc,
260						LAngleLoc, 0, 0, LAngleLoc));
261
262        return ParseFunctionDefinition(DeclaratorInfo,
263                                       ParsedTemplateInfo(&FakedParamLists,
264                                           /*isSpecialization=*/true,
265                                           /*LastParamListWasEmpty=*/true),
266                                       &LateParsedAttrs);
267      }
268    }
269    return ParseFunctionDefinition(DeclaratorInfo, TemplateInfo,
270				   &LateParsedAttrs);
271  }
272
273  // Parse this declaration.
274  Decl *ThisDecl = ParseDeclarationAfterDeclarator(DeclaratorInfo,
275                                                   TemplateInfo);
276
277  if (Tok.is(tok::comma)) {
278    Diag(Tok, diag::err_multiple_template_declarators)
279      << (int)TemplateInfo.Kind;
280    SkipUntil(tok::semi, true, false);
281    return ThisDecl;
282  }
283
284  // Eat the semi colon after the declaration.
285  ExpectAndConsumeSemi(diag::err_expected_semi_declaration);
286  if (LateParsedAttrs.size() > 0)
287    ParseLexedAttributeList(LateParsedAttrs, ThisDecl, true, false);
288  DeclaratorInfo.complete(ThisDecl);
289  return ThisDecl;
290}
291
292/// ParseTemplateParameters - Parses a template-parameter-list enclosed in
293/// angle brackets. Depth is the depth of this template-parameter-list, which
294/// is the number of template headers directly enclosing this template header.
295/// TemplateParams is the current list of template parameters we're building.
296/// The template parameter we parse will be added to this list. LAngleLoc and
297/// RAngleLoc will receive the positions of the '<' and '>', respectively,
298/// that enclose this template parameter list.
299///
300/// \returns true if an error occurred, false otherwise.
301bool Parser::ParseTemplateParameters(unsigned Depth,
302                               SmallVectorImpl<Decl*> &TemplateParams,
303                                     SourceLocation &LAngleLoc,
304                                     SourceLocation &RAngleLoc) {
305  // Get the template parameter list.
306  if (!Tok.is(tok::less)) {
307    Diag(Tok.getLocation(), diag::err_expected_less_after) << "template";
308    return true;
309  }
310  LAngleLoc = ConsumeToken();
311
312  // Try to parse the template parameter list.
313  bool Failed = false;
314  if (!Tok.is(tok::greater) && !Tok.is(tok::greatergreater))
315    Failed = ParseTemplateParameterList(Depth, TemplateParams);
316
317  if (Tok.is(tok::greatergreater)) {
318    // No diagnostic required here: a template-parameter-list can only be
319    // followed by a declaration or, for a template template parameter, the
320    // 'class' keyword. Therefore, the second '>' will be diagnosed later.
321    // This matters for elegant diagnosis of:
322    //   template<template<typename>> struct S;
323    Tok.setKind(tok::greater);
324    RAngleLoc = Tok.getLocation();
325    Tok.setLocation(Tok.getLocation().getLocWithOffset(1));
326  } else if (Tok.is(tok::greater))
327    RAngleLoc = ConsumeToken();
328  else if (Failed) {
329    Diag(Tok.getLocation(), diag::err_expected_greater);
330    return true;
331  }
332  return false;
333}
334
335/// ParseTemplateParameterList - Parse a template parameter list. If
336/// the parsing fails badly (i.e., closing bracket was left out), this
337/// will try to put the token stream in a reasonable position (closing
338/// a statement, etc.) and return false.
339///
340///       template-parameter-list:    [C++ temp]
341///         template-parameter
342///         template-parameter-list ',' template-parameter
343bool
344Parser::ParseTemplateParameterList(unsigned Depth,
345                             SmallVectorImpl<Decl*> &TemplateParams) {
346  while (1) {
347    if (Decl *TmpParam
348          = ParseTemplateParameter(Depth, TemplateParams.size())) {
349      TemplateParams.push_back(TmpParam);
350    } else {
351      // If we failed to parse a template parameter, skip until we find
352      // a comma or closing brace.
353      SkipUntil(tok::comma, tok::greater, tok::greatergreater, true, true);
354    }
355
356    // Did we find a comma or the end of the template parameter list?
357    if (Tok.is(tok::comma)) {
358      ConsumeToken();
359    } else if (Tok.is(tok::greater) || Tok.is(tok::greatergreater)) {
360      // Don't consume this... that's done by template parser.
361      break;
362    } else {
363      // Somebody probably forgot to close the template. Skip ahead and
364      // try to get out of the expression. This error is currently
365      // subsumed by whatever goes on in ParseTemplateParameter.
366      Diag(Tok.getLocation(), diag::err_expected_comma_greater);
367      SkipUntil(tok::comma, tok::greater, tok::greatergreater, true, true);
368      return false;
369    }
370  }
371  return true;
372}
373
374/// \brief Determine whether the parser is at the start of a template
375/// type parameter.
376bool Parser::isStartOfTemplateTypeParameter() {
377  if (Tok.is(tok::kw_class)) {
378    // "class" may be the start of an elaborated-type-specifier or a
379    // type-parameter. Per C++ [temp.param]p3, we prefer the type-parameter.
380    switch (NextToken().getKind()) {
381    case tok::equal:
382    case tok::comma:
383    case tok::greater:
384    case tok::greatergreater:
385    case tok::ellipsis:
386      return true;
387
388    case tok::identifier:
389      // This may be either a type-parameter or an elaborated-type-specifier.
390      // We have to look further.
391      break;
392
393    default:
394      return false;
395    }
396
397    switch (GetLookAheadToken(2).getKind()) {
398    case tok::equal:
399    case tok::comma:
400    case tok::greater:
401    case tok::greatergreater:
402      return true;
403
404    default:
405      return false;
406    }
407  }
408
409  if (Tok.isNot(tok::kw_typename))
410    return false;
411
412  // C++ [temp.param]p2:
413  //   There is no semantic difference between class and typename in a
414  //   template-parameter. typename followed by an unqualified-id
415  //   names a template type parameter. typename followed by a
416  //   qualified-id denotes the type in a non-type
417  //   parameter-declaration.
418  Token Next = NextToken();
419
420  // If we have an identifier, skip over it.
421  if (Next.getKind() == tok::identifier)
422    Next = GetLookAheadToken(2);
423
424  switch (Next.getKind()) {
425  case tok::equal:
426  case tok::comma:
427  case tok::greater:
428  case tok::greatergreater:
429  case tok::ellipsis:
430    return true;
431
432  default:
433    return false;
434  }
435}
436
437/// ParseTemplateParameter - Parse a template-parameter (C++ [temp.param]).
438///
439///       template-parameter: [C++ temp.param]
440///         type-parameter
441///         parameter-declaration
442///
443///       type-parameter: (see below)
444///         'class' ...[opt] identifier[opt]
445///         'class' identifier[opt] '=' type-id
446///         'typename' ...[opt] identifier[opt]
447///         'typename' identifier[opt] '=' type-id
448///         'template' '<' template-parameter-list '>'
449///               'class' ...[opt] identifier[opt]
450///         'template' '<' template-parameter-list '>' 'class' identifier[opt]
451///               = id-expression
452Decl *Parser::ParseTemplateParameter(unsigned Depth, unsigned Position) {
453  if (isStartOfTemplateTypeParameter())
454    return ParseTypeParameter(Depth, Position);
455
456  if (Tok.is(tok::kw_template))
457    return ParseTemplateTemplateParameter(Depth, Position);
458
459  // If it's none of the above, then it must be a parameter declaration.
460  // NOTE: This will pick up errors in the closure of the template parameter
461  // list (e.g., template < ; Check here to implement >> style closures.
462  return ParseNonTypeTemplateParameter(Depth, Position);
463}
464
465/// ParseTypeParameter - Parse a template type parameter (C++ [temp.param]).
466/// Other kinds of template parameters are parsed in
467/// ParseTemplateTemplateParameter and ParseNonTypeTemplateParameter.
468///
469///       type-parameter:     [C++ temp.param]
470///         'class' ...[opt][C++0x] identifier[opt]
471///         'class' identifier[opt] '=' type-id
472///         'typename' ...[opt][C++0x] identifier[opt]
473///         'typename' identifier[opt] '=' type-id
474Decl *Parser::ParseTypeParameter(unsigned Depth, unsigned Position) {
475  assert((Tok.is(tok::kw_class) || Tok.is(tok::kw_typename)) &&
476         "A type-parameter starts with 'class' or 'typename'");
477
478  // Consume the 'class' or 'typename' keyword.
479  bool TypenameKeyword = Tok.is(tok::kw_typename);
480  SourceLocation KeyLoc = ConsumeToken();
481
482  // Grab the ellipsis (if given).
483  bool Ellipsis = false;
484  SourceLocation EllipsisLoc;
485  if (Tok.is(tok::ellipsis)) {
486    Ellipsis = true;
487    EllipsisLoc = ConsumeToken();
488
489    Diag(EllipsisLoc,
490         getLangOpts().CPlusPlus11
491           ? diag::warn_cxx98_compat_variadic_templates
492           : diag::ext_variadic_templates);
493  }
494
495  // Grab the template parameter name (if given)
496  SourceLocation NameLoc;
497  IdentifierInfo* ParamName = 0;
498  if (Tok.is(tok::identifier)) {
499    ParamName = Tok.getIdentifierInfo();
500    NameLoc = ConsumeToken();
501  } else if (Tok.is(tok::equal) || Tok.is(tok::comma) ||
502             Tok.is(tok::greater) || Tok.is(tok::greatergreater)) {
503    // Unnamed template parameter. Don't have to do anything here, just
504    // don't consume this token.
505  } else {
506    Diag(Tok.getLocation(), diag::err_expected_ident);
507    return 0;
508  }
509
510  // Grab a default argument (if available).
511  // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
512  // we introduce the type parameter into the local scope.
513  SourceLocation EqualLoc;
514  ParsedType DefaultArg;
515  if (Tok.is(tok::equal)) {
516    EqualLoc = ConsumeToken();
517    DefaultArg = ParseTypeName(/*Range=*/0,
518                               Declarator::TemplateTypeArgContext).get();
519  }
520
521  return Actions.ActOnTypeParameter(getCurScope(), TypenameKeyword, Ellipsis,
522                                    EllipsisLoc, KeyLoc, ParamName, NameLoc,
523                                    Depth, Position, EqualLoc, DefaultArg);
524}
525
526/// ParseTemplateTemplateParameter - Handle the parsing of template
527/// template parameters.
528///
529///       type-parameter:    [C++ temp.param]
530///         'template' '<' template-parameter-list '>' 'class'
531///                  ...[opt] identifier[opt]
532///         'template' '<' template-parameter-list '>' 'class' identifier[opt]
533///                  = id-expression
534Decl *
535Parser::ParseTemplateTemplateParameter(unsigned Depth, unsigned Position) {
536  assert(Tok.is(tok::kw_template) && "Expected 'template' keyword");
537
538  // Handle the template <...> part.
539  SourceLocation TemplateLoc = ConsumeToken();
540  SmallVector<Decl*,8> TemplateParams;
541  SourceLocation LAngleLoc, RAngleLoc;
542  {
543    ParseScope TemplateParmScope(this, Scope::TemplateParamScope);
544    if (ParseTemplateParameters(Depth + 1, TemplateParams, LAngleLoc,
545                               RAngleLoc)) {
546      return 0;
547    }
548  }
549
550  // Generate a meaningful error if the user forgot to put class before the
551  // identifier, comma, or greater. Provide a fixit if the identifier, comma,
552  // or greater appear immediately or after 'typename' or 'struct'. In the
553  // latter case, replace the keyword with 'class'.
554  if (!Tok.is(tok::kw_class)) {
555    bool Replace = Tok.is(tok::kw_typename) || Tok.is(tok::kw_struct);
556    const Token& Next = Replace ? NextToken() : Tok;
557    if (Next.is(tok::identifier) || Next.is(tok::comma) ||
558        Next.is(tok::greater) || Next.is(tok::greatergreater) ||
559        Next.is(tok::ellipsis))
560      Diag(Tok.getLocation(), diag::err_class_on_template_template_param)
561        << (Replace ? FixItHint::CreateReplacement(Tok.getLocation(), "class")
562                    : FixItHint::CreateInsertion(Tok.getLocation(), "class "));
563    else
564      Diag(Tok.getLocation(), diag::err_class_on_template_template_param);
565
566    if (Replace)
567      ConsumeToken();
568  } else
569    ConsumeToken();
570
571  // Parse the ellipsis, if given.
572  SourceLocation EllipsisLoc;
573  if (Tok.is(tok::ellipsis)) {
574    EllipsisLoc = ConsumeToken();
575
576    Diag(EllipsisLoc,
577         getLangOpts().CPlusPlus11
578           ? diag::warn_cxx98_compat_variadic_templates
579           : diag::ext_variadic_templates);
580  }
581
582  // Get the identifier, if given.
583  SourceLocation NameLoc;
584  IdentifierInfo* ParamName = 0;
585  if (Tok.is(tok::identifier)) {
586    ParamName = Tok.getIdentifierInfo();
587    NameLoc = ConsumeToken();
588  } else if (Tok.is(tok::equal) || Tok.is(tok::comma) ||
589             Tok.is(tok::greater) || Tok.is(tok::greatergreater)) {
590    // Unnamed template parameter. Don't have to do anything here, just
591    // don't consume this token.
592  } else {
593    Diag(Tok.getLocation(), diag::err_expected_ident);
594    return 0;
595  }
596
597  TemplateParameterList *ParamList =
598    Actions.ActOnTemplateParameterList(Depth, SourceLocation(),
599                                       TemplateLoc, LAngleLoc,
600                                       TemplateParams.data(),
601                                       TemplateParams.size(),
602                                       RAngleLoc);
603
604  // Grab a default argument (if available).
605  // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
606  // we introduce the template parameter into the local scope.
607  SourceLocation EqualLoc;
608  ParsedTemplateArgument DefaultArg;
609  if (Tok.is(tok::equal)) {
610    EqualLoc = ConsumeToken();
611    DefaultArg = ParseTemplateTemplateArgument();
612    if (DefaultArg.isInvalid()) {
613      Diag(Tok.getLocation(),
614           diag::err_default_template_template_parameter_not_template);
615      SkipUntil(tok::comma, tok::greater, tok::greatergreater, true, true);
616    }
617  }
618
619  return Actions.ActOnTemplateTemplateParameter(getCurScope(), TemplateLoc,
620                                                ParamList, EllipsisLoc,
621                                                ParamName, NameLoc, Depth,
622                                                Position, EqualLoc, DefaultArg);
623}
624
625/// ParseNonTypeTemplateParameter - Handle the parsing of non-type
626/// template parameters (e.g., in "template<int Size> class array;").
627///
628///       template-parameter:
629///         ...
630///         parameter-declaration
631Decl *
632Parser::ParseNonTypeTemplateParameter(unsigned Depth, unsigned Position) {
633  // Parse the declaration-specifiers (i.e., the type).
634  // FIXME: The type should probably be restricted in some way... Not all
635  // declarators (parts of declarators?) are accepted for parameters.
636  DeclSpec DS(AttrFactory);
637  ParseDeclarationSpecifiers(DS);
638
639  // Parse this as a typename.
640  Declarator ParamDecl(DS, Declarator::TemplateParamContext);
641  ParseDeclarator(ParamDecl);
642  if (DS.getTypeSpecType() == DeclSpec::TST_unspecified) {
643    Diag(Tok.getLocation(), diag::err_expected_template_parameter);
644    return 0;
645  }
646
647  // If there is a default value, parse it.
648  // Per C++0x [basic.scope.pdecl]p9, we parse the default argument before
649  // we introduce the template parameter into the local scope.
650  SourceLocation EqualLoc;
651  ExprResult DefaultArg;
652  if (Tok.is(tok::equal)) {
653    EqualLoc = ConsumeToken();
654
655    // C++ [temp.param]p15:
656    //   When parsing a default template-argument for a non-type
657    //   template-parameter, the first non-nested > is taken as the
658    //   end of the template-parameter-list rather than a greater-than
659    //   operator.
660    GreaterThanIsOperatorScope G(GreaterThanIsOperator, false);
661    EnterExpressionEvaluationContext Unevaluated(Actions, Sema::Unevaluated);
662
663    DefaultArg = ParseAssignmentExpression();
664    if (DefaultArg.isInvalid())
665      SkipUntil(tok::comma, tok::greater, true, true);
666  }
667
668  // Create the parameter.
669  return Actions.ActOnNonTypeTemplateParameter(getCurScope(), ParamDecl,
670                                               Depth, Position, EqualLoc,
671                                               DefaultArg.take());
672}
673
674/// \brief Parses a '>' at the end of a template list.
675///
676/// If this function encounters '>>', '>>>', '>=', or '>>=', it tries
677/// to determine if these tokens were supposed to be a '>' followed by
678/// '>', '>>', '>=', or '>='. It emits an appropriate diagnostic if necessary.
679///
680/// \param RAngleLoc the location of the consumed '>'.
681///
682/// \param ConsumeLastToken if true, the '>' is not consumed.
683bool Parser::ParseGreaterThanInTemplateList(SourceLocation &RAngleLoc,
684                                            bool ConsumeLastToken) {
685  // What will be left once we've consumed the '>'.
686  tok::TokenKind RemainingToken;
687  const char *ReplacementStr = "> >";
688
689  switch (Tok.getKind()) {
690  default:
691    Diag(Tok.getLocation(), diag::err_expected_greater);
692    return true;
693
694  case tok::greater:
695    // Determine the location of the '>' token. Only consume this token
696    // if the caller asked us to.
697    RAngleLoc = Tok.getLocation();
698    if (ConsumeLastToken)
699      ConsumeToken();
700    return false;
701
702  case tok::greatergreater:
703    RemainingToken = tok::greater;
704    break;
705
706  case tok::greatergreatergreater:
707    RemainingToken = tok::greatergreater;
708    break;
709
710  case tok::greaterequal:
711    RemainingToken = tok::equal;
712    ReplacementStr = "> =";
713    break;
714
715  case tok::greatergreaterequal:
716    RemainingToken = tok::greaterequal;
717    break;
718  }
719
720  // This template-id is terminated by a token which starts with a '>'. Outside
721  // C++11, this is now error recovery, and in C++11, this is error recovery if
722  // the token isn't '>>'.
723
724  RAngleLoc = Tok.getLocation();
725
726  // The source range of the '>>' or '>=' at the start of the token.
727  CharSourceRange ReplacementRange =
728      CharSourceRange::getCharRange(RAngleLoc,
729          Lexer::AdvanceToTokenCharacter(RAngleLoc, 2, PP.getSourceManager(),
730                                         getLangOpts()));
731
732  // A hint to put a space between the '>>'s. In order to make the hint as
733  // clear as possible, we include the characters either side of the space in
734  // the replacement, rather than just inserting a space at SecondCharLoc.
735  FixItHint Hint1 = FixItHint::CreateReplacement(ReplacementRange,
736                                                 ReplacementStr);
737
738  // A hint to put another space after the token, if it would otherwise be
739  // lexed differently.
740  FixItHint Hint2;
741  Token Next = NextToken();
742  if ((RemainingToken == tok::greater ||
743       RemainingToken == tok::greatergreater) &&
744      (Next.is(tok::greater) || Next.is(tok::greatergreater) ||
745       Next.is(tok::greatergreatergreater) || Next.is(tok::equal) ||
746       Next.is(tok::greaterequal) || Next.is(tok::greatergreaterequal) ||
747       Next.is(tok::equalequal)) &&
748      areTokensAdjacent(Tok, Next))
749    Hint2 = FixItHint::CreateInsertion(Next.getLocation(), " ");
750
751  unsigned DiagId = diag::err_two_right_angle_brackets_need_space;
752  if (getLangOpts().CPlusPlus11 && Tok.is(tok::greatergreater))
753    DiagId = diag::warn_cxx98_compat_two_right_angle_brackets;
754  else if (Tok.is(tok::greaterequal))
755    DiagId = diag::err_right_angle_bracket_equal_needs_space;
756  Diag(Tok.getLocation(), DiagId) << Hint1 << Hint2;
757
758  // Strip the initial '>' from the token.
759  if (RemainingToken == tok::equal && Next.is(tok::equal) &&
760      areTokensAdjacent(Tok, Next)) {
761    // Join two adjacent '=' tokens into one, for cases like:
762    //   void (*p)() = f<int>;
763    //   return f<int>==p;
764    ConsumeToken();
765    Tok.setKind(tok::equalequal);
766    Tok.setLength(Tok.getLength() + 1);
767  } else {
768    Tok.setKind(RemainingToken);
769    Tok.setLength(Tok.getLength() - 1);
770  }
771  Tok.setLocation(Lexer::AdvanceToTokenCharacter(RAngleLoc, 1,
772                                                 PP.getSourceManager(),
773                                                 getLangOpts()));
774
775  if (!ConsumeLastToken) {
776    // Since we're not supposed to consume the '>' token, we need to push
777    // this token and revert the current token back to the '>'.
778    PP.EnterToken(Tok);
779    Tok.setKind(tok::greater);
780    Tok.setLength(1);
781    Tok.setLocation(RAngleLoc);
782  }
783  return false;
784}
785
786
787/// \brief Parses a template-id that after the template name has
788/// already been parsed.
789///
790/// This routine takes care of parsing the enclosed template argument
791/// list ('<' template-parameter-list [opt] '>') and placing the
792/// results into a form that can be transferred to semantic analysis.
793///
794/// \param Template the template declaration produced by isTemplateName
795///
796/// \param TemplateNameLoc the source location of the template name
797///
798/// \param SS if non-NULL, the nested-name-specifier preceding the
799/// template name.
800///
801/// \param ConsumeLastToken if true, then we will consume the last
802/// token that forms the template-id. Otherwise, we will leave the
803/// last token in the stream (e.g., so that it can be replaced with an
804/// annotation token).
805bool
806Parser::ParseTemplateIdAfterTemplateName(TemplateTy Template,
807                                         SourceLocation TemplateNameLoc,
808                                         const CXXScopeSpec &SS,
809                                         bool ConsumeLastToken,
810                                         SourceLocation &LAngleLoc,
811                                         TemplateArgList &TemplateArgs,
812                                         SourceLocation &RAngleLoc) {
813  assert(Tok.is(tok::less) && "Must have already parsed the template-name");
814
815  // Consume the '<'.
816  LAngleLoc = ConsumeToken();
817
818  // Parse the optional template-argument-list.
819  bool Invalid = false;
820  {
821    GreaterThanIsOperatorScope G(GreaterThanIsOperator, false);
822    if (Tok.isNot(tok::greater) && Tok.isNot(tok::greatergreater))
823      Invalid = ParseTemplateArgumentList(TemplateArgs);
824
825    if (Invalid) {
826      // Try to find the closing '>'.
827      SkipUntil(tok::greater, true, !ConsumeLastToken);
828
829      return true;
830    }
831  }
832
833  return ParseGreaterThanInTemplateList(RAngleLoc, ConsumeLastToken);
834}
835
836/// \brief Replace the tokens that form a simple-template-id with an
837/// annotation token containing the complete template-id.
838///
839/// The first token in the stream must be the name of a template that
840/// is followed by a '<'. This routine will parse the complete
841/// simple-template-id and replace the tokens with a single annotation
842/// token with one of two different kinds: if the template-id names a
843/// type (and \p AllowTypeAnnotation is true), the annotation token is
844/// a type annotation that includes the optional nested-name-specifier
845/// (\p SS). Otherwise, the annotation token is a template-id
846/// annotation that does not include the optional
847/// nested-name-specifier.
848///
849/// \param Template  the declaration of the template named by the first
850/// token (an identifier), as returned from \c Action::isTemplateName().
851///
852/// \param TNK the kind of template that \p Template
853/// refers to, as returned from \c Action::isTemplateName().
854///
855/// \param SS if non-NULL, the nested-name-specifier that precedes
856/// this template name.
857///
858/// \param TemplateKWLoc if valid, specifies that this template-id
859/// annotation was preceded by the 'template' keyword and gives the
860/// location of that keyword. If invalid (the default), then this
861/// template-id was not preceded by a 'template' keyword.
862///
863/// \param AllowTypeAnnotation if true (the default), then a
864/// simple-template-id that refers to a class template, template
865/// template parameter, or other template that produces a type will be
866/// replaced with a type annotation token. Otherwise, the
867/// simple-template-id is always replaced with a template-id
868/// annotation token.
869///
870/// If an unrecoverable parse error occurs and no annotation token can be
871/// formed, this function returns true.
872///
873bool Parser::AnnotateTemplateIdToken(TemplateTy Template, TemplateNameKind TNK,
874                                     CXXScopeSpec &SS,
875                                     SourceLocation TemplateKWLoc,
876                                     UnqualifiedId &TemplateName,
877                                     bool AllowTypeAnnotation) {
878  assert(getLangOpts().CPlusPlus && "Can only annotate template-ids in C++");
879  assert(Template && Tok.is(tok::less) &&
880         "Parser isn't at the beginning of a template-id");
881
882  // Consume the template-name.
883  SourceLocation TemplateNameLoc = TemplateName.getSourceRange().getBegin();
884
885  // Parse the enclosed template argument list.
886  SourceLocation LAngleLoc, RAngleLoc;
887  TemplateArgList TemplateArgs;
888  bool Invalid = ParseTemplateIdAfterTemplateName(Template,
889                                                  TemplateNameLoc,
890                                                  SS, false, LAngleLoc,
891                                                  TemplateArgs,
892                                                  RAngleLoc);
893
894  if (Invalid) {
895    // If we failed to parse the template ID but skipped ahead to a >, we're not
896    // going to be able to form a token annotation.  Eat the '>' if present.
897    if (Tok.is(tok::greater))
898      ConsumeToken();
899    return true;
900  }
901
902  ASTTemplateArgsPtr TemplateArgsPtr(TemplateArgs);
903
904  // Build the annotation token.
905  if (TNK == TNK_Type_template && AllowTypeAnnotation) {
906    TypeResult Type
907      = Actions.ActOnTemplateIdType(SS, TemplateKWLoc,
908                                    Template, TemplateNameLoc,
909                                    LAngleLoc, TemplateArgsPtr, RAngleLoc);
910    if (Type.isInvalid()) {
911      // If we failed to parse the template ID but skipped ahead to a >, we're not
912      // going to be able to form a token annotation.  Eat the '>' if present.
913      if (Tok.is(tok::greater))
914        ConsumeToken();
915      return true;
916    }
917
918    Tok.setKind(tok::annot_typename);
919    setTypeAnnotation(Tok, Type.get());
920    if (SS.isNotEmpty())
921      Tok.setLocation(SS.getBeginLoc());
922    else if (TemplateKWLoc.isValid())
923      Tok.setLocation(TemplateKWLoc);
924    else
925      Tok.setLocation(TemplateNameLoc);
926  } else {
927    // Build a template-id annotation token that can be processed
928    // later.
929    Tok.setKind(tok::annot_template_id);
930    TemplateIdAnnotation *TemplateId
931      = TemplateIdAnnotation::Allocate(TemplateArgs.size(), TemplateIds);
932    TemplateId->TemplateNameLoc = TemplateNameLoc;
933    if (TemplateName.getKind() == UnqualifiedId::IK_Identifier) {
934      TemplateId->Name = TemplateName.Identifier;
935      TemplateId->Operator = OO_None;
936    } else {
937      TemplateId->Name = 0;
938      TemplateId->Operator = TemplateName.OperatorFunctionId.Operator;
939    }
940    TemplateId->SS = SS;
941    TemplateId->TemplateKWLoc = TemplateKWLoc;
942    TemplateId->Template = Template;
943    TemplateId->Kind = TNK;
944    TemplateId->LAngleLoc = LAngleLoc;
945    TemplateId->RAngleLoc = RAngleLoc;
946    ParsedTemplateArgument *Args = TemplateId->getTemplateArgs();
947    for (unsigned Arg = 0, ArgEnd = TemplateArgs.size(); Arg != ArgEnd; ++Arg)
948      Args[Arg] = ParsedTemplateArgument(TemplateArgs[Arg]);
949    Tok.setAnnotationValue(TemplateId);
950    if (TemplateKWLoc.isValid())
951      Tok.setLocation(TemplateKWLoc);
952    else
953      Tok.setLocation(TemplateNameLoc);
954  }
955
956  // Common fields for the annotation token
957  Tok.setAnnotationEndLoc(RAngleLoc);
958
959  // In case the tokens were cached, have Preprocessor replace them with the
960  // annotation token.
961  PP.AnnotateCachedTokens(Tok);
962  return false;
963}
964
965/// \brief Replaces a template-id annotation token with a type
966/// annotation token.
967///
968/// If there was a failure when forming the type from the template-id,
969/// a type annotation token will still be created, but will have a
970/// NULL type pointer to signify an error.
971void Parser::AnnotateTemplateIdTokenAsType() {
972  assert(Tok.is(tok::annot_template_id) && "Requires template-id tokens");
973
974  TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok);
975  assert((TemplateId->Kind == TNK_Type_template ||
976          TemplateId->Kind == TNK_Dependent_template_name) &&
977         "Only works for type and dependent templates");
978
979  ASTTemplateArgsPtr TemplateArgsPtr(TemplateId->getTemplateArgs(),
980                                     TemplateId->NumArgs);
981
982  TypeResult Type
983    = Actions.ActOnTemplateIdType(TemplateId->SS,
984                                  TemplateId->TemplateKWLoc,
985                                  TemplateId->Template,
986                                  TemplateId->TemplateNameLoc,
987                                  TemplateId->LAngleLoc,
988                                  TemplateArgsPtr,
989                                  TemplateId->RAngleLoc);
990  // Create the new "type" annotation token.
991  Tok.setKind(tok::annot_typename);
992  setTypeAnnotation(Tok, Type.isInvalid() ? ParsedType() : Type.get());
993  if (TemplateId->SS.isNotEmpty()) // it was a C++ qualified type name.
994    Tok.setLocation(TemplateId->SS.getBeginLoc());
995  // End location stays the same
996
997  // Replace the template-id annotation token, and possible the scope-specifier
998  // that precedes it, with the typename annotation token.
999  PP.AnnotateCachedTokens(Tok);
1000}
1001
1002/// \brief Determine whether the given token can end a template argument.
1003static bool isEndOfTemplateArgument(Token Tok) {
1004  return Tok.is(tok::comma) || Tok.is(tok::greater) ||
1005         Tok.is(tok::greatergreater);
1006}
1007
1008/// \brief Parse a C++ template template argument.
1009ParsedTemplateArgument Parser::ParseTemplateTemplateArgument() {
1010  if (!Tok.is(tok::identifier) && !Tok.is(tok::coloncolon) &&
1011      !Tok.is(tok::annot_cxxscope))
1012    return ParsedTemplateArgument();
1013
1014  // C++0x [temp.arg.template]p1:
1015  //   A template-argument for a template template-parameter shall be the name
1016  //   of a class template or an alias template, expressed as id-expression.
1017  //
1018  // We parse an id-expression that refers to a class template or alias
1019  // template. The grammar we parse is:
1020  //
1021  //   nested-name-specifier[opt] template[opt] identifier ...[opt]
1022  //
1023  // followed by a token that terminates a template argument, such as ',',
1024  // '>', or (in some cases) '>>'.
1025  CXXScopeSpec SS; // nested-name-specifier, if present
1026  ParseOptionalCXXScopeSpecifier(SS, ParsedType(),
1027                                 /*EnteringContext=*/false);
1028
1029  ParsedTemplateArgument Result;
1030  SourceLocation EllipsisLoc;
1031  if (SS.isSet() && Tok.is(tok::kw_template)) {
1032    // Parse the optional 'template' keyword following the
1033    // nested-name-specifier.
1034    SourceLocation TemplateKWLoc = ConsumeToken();
1035
1036    if (Tok.is(tok::identifier)) {
1037      // We appear to have a dependent template name.
1038      UnqualifiedId Name;
1039      Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation());
1040      ConsumeToken(); // the identifier
1041
1042      // Parse the ellipsis.
1043      if (Tok.is(tok::ellipsis))
1044        EllipsisLoc = ConsumeToken();
1045
1046      // If the next token signals the end of a template argument,
1047      // then we have a dependent template name that could be a template
1048      // template argument.
1049      TemplateTy Template;
1050      if (isEndOfTemplateArgument(Tok) &&
1051          Actions.ActOnDependentTemplateName(getCurScope(),
1052                                             SS, TemplateKWLoc, Name,
1053                                             /*ObjectType=*/ ParsedType(),
1054                                             /*EnteringContext=*/false,
1055                                             Template))
1056        Result = ParsedTemplateArgument(SS, Template, Name.StartLocation);
1057    }
1058  } else if (Tok.is(tok::identifier)) {
1059    // We may have a (non-dependent) template name.
1060    TemplateTy Template;
1061    UnqualifiedId Name;
1062    Name.setIdentifier(Tok.getIdentifierInfo(), Tok.getLocation());
1063    ConsumeToken(); // the identifier
1064
1065    // Parse the ellipsis.
1066    if (Tok.is(tok::ellipsis))
1067      EllipsisLoc = ConsumeToken();
1068
1069    if (isEndOfTemplateArgument(Tok)) {
1070      bool MemberOfUnknownSpecialization;
1071      TemplateNameKind TNK = Actions.isTemplateName(getCurScope(), SS,
1072                                               /*hasTemplateKeyword=*/false,
1073                                                    Name,
1074                                               /*ObjectType=*/ ParsedType(),
1075                                                    /*EnteringContext=*/false,
1076                                                    Template,
1077                                                MemberOfUnknownSpecialization);
1078      if (TNK == TNK_Dependent_template_name || TNK == TNK_Type_template) {
1079        // We have an id-expression that refers to a class template or
1080        // (C++0x) alias template.
1081        Result = ParsedTemplateArgument(SS, Template, Name.StartLocation);
1082      }
1083    }
1084  }
1085
1086  // If this is a pack expansion, build it as such.
1087  if (EllipsisLoc.isValid() && !Result.isInvalid())
1088    Result = Actions.ActOnPackExpansion(Result, EllipsisLoc);
1089
1090  return Result;
1091}
1092
1093/// ParseTemplateArgument - Parse a C++ template argument (C++ [temp.names]).
1094///
1095///       template-argument: [C++ 14.2]
1096///         constant-expression
1097///         type-id
1098///         id-expression
1099ParsedTemplateArgument Parser::ParseTemplateArgument() {
1100  // C++ [temp.arg]p2:
1101  //   In a template-argument, an ambiguity between a type-id and an
1102  //   expression is resolved to a type-id, regardless of the form of
1103  //   the corresponding template-parameter.
1104  //
1105  // Therefore, we initially try to parse a type-id.
1106  if (isCXXTypeId(TypeIdAsTemplateArgument)) {
1107    SourceLocation Loc = Tok.getLocation();
1108    TypeResult TypeArg = ParseTypeName(/*Range=*/0,
1109                                       Declarator::TemplateTypeArgContext);
1110    if (TypeArg.isInvalid())
1111      return ParsedTemplateArgument();
1112
1113    return ParsedTemplateArgument(ParsedTemplateArgument::Type,
1114                                  TypeArg.get().getAsOpaquePtr(),
1115                                  Loc);
1116  }
1117
1118  // Try to parse a template template argument.
1119  {
1120    TentativeParsingAction TPA(*this);
1121
1122    ParsedTemplateArgument TemplateTemplateArgument
1123      = ParseTemplateTemplateArgument();
1124    if (!TemplateTemplateArgument.isInvalid()) {
1125      TPA.Commit();
1126      return TemplateTemplateArgument;
1127    }
1128
1129    // Revert this tentative parse to parse a non-type template argument.
1130    TPA.Revert();
1131  }
1132
1133  // Parse a non-type template argument.
1134  SourceLocation Loc = Tok.getLocation();
1135  ExprResult ExprArg = ParseConstantExpression(MaybeTypeCast);
1136  if (ExprArg.isInvalid() || !ExprArg.get())
1137    return ParsedTemplateArgument();
1138
1139  return ParsedTemplateArgument(ParsedTemplateArgument::NonType,
1140                                ExprArg.release(), Loc);
1141}
1142
1143/// \brief Determine whether the current tokens can only be parsed as a
1144/// template argument list (starting with the '<') and never as a '<'
1145/// expression.
1146bool Parser::IsTemplateArgumentList(unsigned Skip) {
1147  struct AlwaysRevertAction : TentativeParsingAction {
1148    AlwaysRevertAction(Parser &P) : TentativeParsingAction(P) { }
1149    ~AlwaysRevertAction() { Revert(); }
1150  } Tentative(*this);
1151
1152  while (Skip) {
1153    ConsumeToken();
1154    --Skip;
1155  }
1156
1157  // '<'
1158  if (!Tok.is(tok::less))
1159    return false;
1160  ConsumeToken();
1161
1162  // An empty template argument list.
1163  if (Tok.is(tok::greater))
1164    return true;
1165
1166  // See whether we have declaration specifiers, which indicate a type.
1167  while (isCXXDeclarationSpecifier() == TPResult::True())
1168    ConsumeToken();
1169
1170  // If we have a '>' or a ',' then this is a template argument list.
1171  return Tok.is(tok::greater) || Tok.is(tok::comma);
1172}
1173
1174/// ParseTemplateArgumentList - Parse a C++ template-argument-list
1175/// (C++ [temp.names]). Returns true if there was an error.
1176///
1177///       template-argument-list: [C++ 14.2]
1178///         template-argument
1179///         template-argument-list ',' template-argument
1180bool
1181Parser::ParseTemplateArgumentList(TemplateArgList &TemplateArgs) {
1182  // Template argument lists are constant-evaluation contexts.
1183  EnterExpressionEvaluationContext EvalContext(Actions,Sema::ConstantEvaluated);
1184
1185  while (true) {
1186    ParsedTemplateArgument Arg = ParseTemplateArgument();
1187    if (Tok.is(tok::ellipsis)) {
1188      SourceLocation EllipsisLoc  = ConsumeToken();
1189      Arg = Actions.ActOnPackExpansion(Arg, EllipsisLoc);
1190    }
1191
1192    if (Arg.isInvalid()) {
1193      SkipUntil(tok::comma, tok::greater, true, true);
1194      return true;
1195    }
1196
1197    // Save this template argument.
1198    TemplateArgs.push_back(Arg);
1199
1200    // If the next token is a comma, consume it and keep reading
1201    // arguments.
1202    if (Tok.isNot(tok::comma)) break;
1203
1204    // Consume the comma.
1205    ConsumeToken();
1206  }
1207
1208  return false;
1209}
1210
1211/// \brief Parse a C++ explicit template instantiation
1212/// (C++ [temp.explicit]).
1213///
1214///       explicit-instantiation:
1215///         'extern' [opt] 'template' declaration
1216///
1217/// Note that the 'extern' is a GNU extension and C++11 feature.
1218Decl *Parser::ParseExplicitInstantiation(unsigned Context,
1219                                         SourceLocation ExternLoc,
1220                                         SourceLocation TemplateLoc,
1221                                         SourceLocation &DeclEnd,
1222                                         AccessSpecifier AS) {
1223  // This isn't really required here.
1224  ParsingDeclRAIIObject
1225    ParsingTemplateParams(*this, ParsingDeclRAIIObject::NoParent);
1226
1227  return ParseSingleDeclarationAfterTemplate(Context,
1228                                             ParsedTemplateInfo(ExternLoc,
1229                                                                TemplateLoc),
1230                                             ParsingTemplateParams,
1231                                             DeclEnd, AS);
1232}
1233
1234SourceRange Parser::ParsedTemplateInfo::getSourceRange() const {
1235  if (TemplateParams)
1236    return getTemplateParamsRange(TemplateParams->data(),
1237                                  TemplateParams->size());
1238
1239  SourceRange R(TemplateLoc);
1240  if (ExternLoc.isValid())
1241    R.setBegin(ExternLoc);
1242  return R;
1243}
1244
1245void Parser::LateTemplateParserCallback(void *P, const FunctionDecl *FD) {
1246  ((Parser*)P)->LateTemplateParser(FD);
1247}
1248
1249
1250void Parser::LateTemplateParser(const FunctionDecl *FD) {
1251  LateParsedTemplatedFunction *LPT = LateParsedTemplateMap[FD];
1252  if (LPT) {
1253    ParseLateTemplatedFuncDef(*LPT);
1254    return;
1255  }
1256
1257  llvm_unreachable("Late templated function without associated lexed tokens");
1258}
1259
1260/// \brief Late parse a C++ function template in Microsoft mode.
1261void Parser::ParseLateTemplatedFuncDef(LateParsedTemplatedFunction &LMT) {
1262  if(!LMT.D)
1263     return;
1264
1265  // Get the FunctionDecl.
1266  FunctionTemplateDecl *FunTmplD = dyn_cast<FunctionTemplateDecl>(LMT.D);
1267  FunctionDecl *FunD =
1268      FunTmplD ? FunTmplD->getTemplatedDecl() : cast<FunctionDecl>(LMT.D);
1269  // Track template parameter depth.
1270  TemplateParameterDepthRAII CurTemplateDepthTracker(TemplateParameterDepth);
1271
1272  // To restore the context after late parsing.
1273  Sema::ContextRAII GlobalSavedContext(Actions, Actions.CurContext);
1274
1275  SmallVector<ParseScope*, 4> TemplateParamScopeStack;
1276
1277  // Get the list of DeclContexts to reenter.
1278  SmallVector<DeclContext*, 4> DeclContextsToReenter;
1279  DeclContext *DD = FunD->getLexicalParent();
1280  while (DD && !DD->isTranslationUnit()) {
1281    DeclContextsToReenter.push_back(DD);
1282    DD = DD->getLexicalParent();
1283  }
1284
1285  // Reenter template scopes from outermost to innermost.
1286  SmallVector<DeclContext*, 4>::reverse_iterator II =
1287      DeclContextsToReenter.rbegin();
1288  for (; II != DeclContextsToReenter.rend(); ++II) {
1289    if (ClassTemplatePartialSpecializationDecl *MD =
1290            dyn_cast_or_null<ClassTemplatePartialSpecializationDecl>(*II)) {
1291      TemplateParamScopeStack.push_back(
1292          new ParseScope(this, Scope::TemplateParamScope));
1293      Actions.ActOnReenterTemplateScope(getCurScope(), MD);
1294      ++CurTemplateDepthTracker;
1295    } else if (CXXRecordDecl *MD = dyn_cast_or_null<CXXRecordDecl>(*II)) {
1296      bool IsClassTemplate = MD->getDescribedClassTemplate() != 0;
1297      TemplateParamScopeStack.push_back(
1298          new ParseScope(this, Scope::TemplateParamScope,
1299                        /*ManageScope*/IsClassTemplate));
1300      Actions.ActOnReenterTemplateScope(getCurScope(),
1301                                        MD->getDescribedClassTemplate());
1302      if (IsClassTemplate)
1303        ++CurTemplateDepthTracker;
1304    }
1305    TemplateParamScopeStack.push_back(new ParseScope(this, Scope::DeclScope));
1306    Actions.PushDeclContext(Actions.getCurScope(), *II);
1307  }
1308  TemplateParamScopeStack.push_back(
1309      new ParseScope(this, Scope::TemplateParamScope));
1310
1311  DeclaratorDecl *Declarator = dyn_cast<DeclaratorDecl>(FunD);
1312  if (Declarator && Declarator->getNumTemplateParameterLists() != 0) {
1313    Actions.ActOnReenterDeclaratorTemplateScope(getCurScope(), Declarator);
1314    ++CurTemplateDepthTracker;
1315  }
1316  Actions.ActOnReenterTemplateScope(getCurScope(), LMT.D);
1317  ++CurTemplateDepthTracker;
1318
1319  assert(!LMT.Toks.empty() && "Empty body!");
1320
1321  // Append the current token at the end of the new token stream so that it
1322  // doesn't get lost.
1323  LMT.Toks.push_back(Tok);
1324  PP.EnterTokenStream(LMT.Toks.data(), LMT.Toks.size(), true, false);
1325
1326  // Consume the previously pushed token.
1327  ConsumeAnyToken(/*ConsumeCodeCompletionTok=*/true);
1328  assert((Tok.is(tok::l_brace) || Tok.is(tok::colon) || Tok.is(tok::kw_try))
1329         && "Inline method not starting with '{', ':' or 'try'");
1330
1331  // Parse the method body. Function body parsing code is similar enough
1332  // to be re-used for method bodies as well.
1333  ParseScope FnScope(this, Scope::FnScope|Scope::DeclScope);
1334
1335  // Recreate the containing function DeclContext.
1336  Sema::ContextRAII FunctionSavedContext(Actions, Actions.getContainingDC(FunD));
1337
1338  Actions.ActOnStartOfFunctionDef(getCurScope(), FunD);
1339
1340  if (Tok.is(tok::kw_try)) {
1341    ParseFunctionTryBlock(LMT.D, FnScope);
1342  } else {
1343    if (Tok.is(tok::colon))
1344      ParseConstructorInitializer(LMT.D);
1345    else
1346      Actions.ActOnDefaultCtorInitializers(LMT.D);
1347
1348    if (Tok.is(tok::l_brace)) {
1349      assert((!FunTmplD || FunTmplD->getTemplateParameters()->getDepth() <
1350                               TemplateParameterDepth) &&
1351             "TemplateParameterDepth should be greater than the depth of "
1352             "current template being instantiated!");
1353      ParseFunctionStatementBody(LMT.D, FnScope);
1354      Actions.MarkAsLateParsedTemplate(FunD, false);
1355    } else
1356      Actions.ActOnFinishFunctionBody(LMT.D, 0);
1357  }
1358
1359  // Exit scopes.
1360  FnScope.Exit();
1361  SmallVector<ParseScope*, 4>::reverse_iterator I =
1362   TemplateParamScopeStack.rbegin();
1363  for (; I != TemplateParamScopeStack.rend(); ++I)
1364    delete *I;
1365
1366  DeclGroupPtrTy grp = Actions.ConvertDeclToDeclGroup(LMT.D);
1367  if (grp)
1368    Actions.getASTConsumer().HandleTopLevelDecl(grp.get());
1369}
1370
1371/// \brief Lex a delayed template function for late parsing.
1372void Parser::LexTemplateFunctionForLateParsing(CachedTokens &Toks) {
1373  tok::TokenKind kind = Tok.getKind();
1374  if (!ConsumeAndStoreFunctionPrologue(Toks)) {
1375    // Consume everything up to (and including) the matching right brace.
1376    ConsumeAndStoreUntil(tok::r_brace, Toks, /*StopAtSemi=*/false);
1377  }
1378
1379  // If we're in a function-try-block, we need to store all the catch blocks.
1380  if (kind == tok::kw_try) {
1381    while (Tok.is(tok::kw_catch)) {
1382      ConsumeAndStoreUntil(tok::l_brace, Toks, /*StopAtSemi=*/false);
1383      ConsumeAndStoreUntil(tok::r_brace, Toks, /*StopAtSemi=*/false);
1384    }
1385  }
1386}
1387