1 //===--- ParseTentative.cpp - Ambiguity Resolution Parsing ----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the tentative parsing portions of the Parser
11 // interfaces, for ambiguity resolution.
13 //===----------------------------------------------------------------------===//
15 #include "clang/Parse/Parser.h"
16 #include "clang/Parse/ParseDiagnostic.h"
17 #include "clang/Sema/ParsedTemplate.h"
18 using namespace clang;
20 /// isCXXDeclarationStatement - C++-specialized function that disambiguates
21 /// between a declaration or an expression statement, when parsing function
22 /// bodies. Returns true for declaration, false for expression.
24 /// declaration-statement:
27 /// block-declaration:
28 /// simple-declaration
30 /// namespace-alias-definition
33 /// [C++0x] static_assert-declaration
36 /// 'asm' '(' string-literal ')' ';'
38 /// namespace-alias-definition:
39 /// 'namespace' identifier = qualified-namespace-specifier ';'
41 /// using-declaration:
42 /// 'using' typename[opt] '::'[opt] nested-name-specifier
43 /// unqualified-id ';'
44 /// 'using' '::' unqualified-id ;
47 /// 'using' 'namespace' '::'[opt] nested-name-specifier[opt]
48 /// namespace-name ';'
50 bool Parser::isCXXDeclarationStatement() {
51 switch (Tok.getKind()) {
54 // namespace-alias-definition
55 case tok::kw_namespace:
59 // static_assert-declaration
60 case tok::kw_static_assert:
61 case tok::kw__Static_assert:
65 return isCXXSimpleDeclaration();
69 /// isCXXSimpleDeclaration - C++-specialized function that disambiguates
70 /// between a simple-declaration or an expression-statement.
71 /// If during the disambiguation process a parsing error is encountered,
72 /// the function returns true to let the declaration parsing code handle it.
73 /// Returns false if the statement is disambiguated as expression.
75 /// simple-declaration:
76 /// decl-specifier-seq init-declarator-list[opt] ';'
78 bool Parser::isCXXSimpleDeclaration() {
80 // There is an ambiguity in the grammar involving expression-statements and
81 // declarations: An expression-statement with a function-style explicit type
82 // conversion (5.2.3) as its leftmost subexpression can be indistinguishable
83 // from a declaration where the first declarator starts with a '('. In those
84 // cases the statement is a declaration. [Note: To disambiguate, the whole
85 // statement might have to be examined to determine if it is an
86 // expression-statement or a declaration].
89 // The disambiguation is purely syntactic; that is, the meaning of the names
90 // occurring in such a statement, beyond whether they are type-names or not,
91 // is not generally used in or changed by the disambiguation. Class
92 // templates are instantiated as necessary to determine if a qualified name
93 // is a type-name. Disambiguation precedes parsing, and a statement
94 // disambiguated as a declaration may be an ill-formed declaration.
96 // We don't have to parse all of the decl-specifier-seq part. There's only
97 // an ambiguity if the first decl-specifier is
98 // simple-type-specifier/typename-specifier followed by a '(', which may
99 // indicate a function-style cast expression.
100 // isCXXDeclarationSpecifier will return TPResult::Ambiguous() only in such
103 TPResult TPR = isCXXDeclarationSpecifier();
104 if (TPR != TPResult::Ambiguous())
105 return TPR != TPResult::False(); // Returns true for TPResult::True() or
106 // TPResult::Error().
108 // FIXME: Add statistics about the number of ambiguous statements encountered
109 // and how they were resolved (number of declarations+number of expressions).
111 // Ok, we have a simple-type-specifier/typename-specifier followed by a '('.
112 // We need tentative parsing...
114 TentativeParsingAction PA(*this);
115 TPR = TryParseSimpleDeclaration();
118 // In case of an error, let the declaration parsing code handle it.
119 if (TPR == TPResult::Error())
122 // Declarations take precedence over expressions.
123 if (TPR == TPResult::Ambiguous())
124 TPR = TPResult::True();
126 assert(TPR == TPResult::True() || TPR == TPResult::False());
127 return TPR == TPResult::True();
130 /// simple-declaration:
131 /// decl-specifier-seq init-declarator-list[opt] ';'
133 Parser::TPResult Parser::TryParseSimpleDeclaration() {
134 // We know that we have a simple-type-specifier/typename-specifier followed
136 assert(isCXXDeclarationSpecifier() == TPResult::Ambiguous());
138 if (Tok.is(tok::kw_typeof))
139 TryParseTypeofSpecifier();
143 if (getLang().ObjC1 && Tok.is(tok::less))
144 TryParseProtocolQualifiers();
147 assert(Tok.is(tok::l_paren) && "Expected '('");
149 TPResult TPR = TryParseInitDeclaratorList();
150 if (TPR != TPResult::Ambiguous())
153 if (Tok.isNot(tok::semi))
154 return TPResult::False();
156 return TPResult::Ambiguous();
159 /// init-declarator-list:
161 /// init-declarator-list ',' init-declarator
164 /// declarator initializer[opt]
165 /// [GNU] declarator simple-asm-expr[opt] attributes[opt] initializer[opt]
168 /// '=' initializer-clause
169 /// '(' expression-list ')'
171 /// initializer-clause:
172 /// assignment-expression
173 /// '{' initializer-list ','[opt] '}'
176 Parser::TPResult Parser::TryParseInitDeclaratorList() {
179 TPResult TPR = TryParseDeclarator(false/*mayBeAbstract*/);
180 if (TPR != TPResult::Ambiguous())
183 // [GNU] simple-asm-expr[opt] attributes[opt]
184 if (Tok.is(tok::kw_asm) || Tok.is(tok::kw___attribute))
185 return TPResult::True();
188 if (Tok.is(tok::l_paren)) {
189 // Parse through the parens.
191 if (!SkipUntil(tok::r_paren))
192 return TPResult::Error();
193 } else if (Tok.is(tok::equal) || isTokIdentifier_in()) {
194 // MSVC and g++ won't examine the rest of declarators if '=' is
195 // encountered; they just conclude that we have a declaration.
196 // EDG parses the initializer completely, which is the proper behavior
199 // At present, Clang follows MSVC and g++, since the parser does not have
200 // the ability to parse an expression fully without recording the
201 // results of that parse.
202 // Also allow 'in' after on objective-c declaration as in:
203 // for (int (^b)(void) in array). Ideally this should be done in the
204 // context of parsing for-init-statement of a foreach statement only. But,
205 // in any other context 'in' is invalid after a declaration and parser
206 // issues the error regardless of outcome of this decision.
207 // FIXME. Change if above assumption does not hold.
208 return TPResult::True();
211 if (Tok.isNot(tok::comma))
213 ConsumeToken(); // the comma.
216 return TPResult::Ambiguous();
219 /// isCXXConditionDeclaration - Disambiguates between a declaration or an
220 /// expression for a condition of a if/switch/while/for statement.
221 /// If during the disambiguation process a parsing error is encountered,
222 /// the function returns true to let the declaration parsing code handle it.
226 /// type-specifier-seq declarator '=' assignment-expression
227 /// [GNU] type-specifier-seq declarator simple-asm-expr[opt] attributes[opt]
228 /// '=' assignment-expression
230 bool Parser::isCXXConditionDeclaration() {
231 TPResult TPR = isCXXDeclarationSpecifier();
232 if (TPR != TPResult::Ambiguous())
233 return TPR != TPResult::False(); // Returns true for TPResult::True() or
234 // TPResult::Error().
236 // FIXME: Add statistics about the number of ambiguous statements encountered
237 // and how they were resolved (number of declarations+number of expressions).
239 // Ok, we have a simple-type-specifier/typename-specifier followed by a '('.
240 // We need tentative parsing...
242 TentativeParsingAction PA(*this);
244 // type-specifier-seq
245 if (Tok.is(tok::kw_typeof))
246 TryParseTypeofSpecifier();
250 if (getLang().ObjC1 && Tok.is(tok::less))
251 TryParseProtocolQualifiers();
253 assert(Tok.is(tok::l_paren) && "Expected '('");
256 TPR = TryParseDeclarator(false/*mayBeAbstract*/);
258 // In case of an error, let the declaration parsing code handle it.
259 if (TPR == TPResult::Error())
260 TPR = TPResult::True();
262 if (TPR == TPResult::Ambiguous()) {
264 // [GNU] simple-asm-expr[opt] attributes[opt]
265 if (Tok.is(tok::equal) ||
266 Tok.is(tok::kw_asm) || Tok.is(tok::kw___attribute))
267 TPR = TPResult::True();
269 TPR = TPResult::False();
274 assert(TPR == TPResult::True() || TPR == TPResult::False());
275 return TPR == TPResult::True();
278 /// \brief Determine whether the next set of tokens contains a type-id.
280 /// The context parameter states what context we're parsing right
281 /// now, which affects how this routine copes with the token
282 /// following the type-id. If the context is TypeIdInParens, we have
283 /// already parsed the '(' and we will cease lookahead when we hit
284 /// the corresponding ')'. If the context is
285 /// TypeIdAsTemplateArgument, we've already parsed the '<' or ','
286 /// before this template argument, and will cease lookahead when we
287 /// hit a '>', '>>' (in C++0x), or ','. Returns true for a type-id
288 /// and false for an expression. If during the disambiguation
289 /// process a parsing error is encountered, the function returns
290 /// true to let the declaration parsing code handle it.
293 /// type-specifier-seq abstract-declarator[opt]
295 bool Parser::isCXXTypeId(TentativeCXXTypeIdContext Context, bool &isAmbiguous) {
300 // The ambiguity arising from the similarity between a function-style cast and
301 // a type-id can occur in different contexts. The ambiguity appears as a
302 // choice between a function-style cast expression and a declaration of a
303 // type. The resolution is that any construct that could possibly be a type-id
304 // in its syntactic context shall be considered a type-id.
306 TPResult TPR = isCXXDeclarationSpecifier();
307 if (TPR != TPResult::Ambiguous())
308 return TPR != TPResult::False(); // Returns true for TPResult::True() or
309 // TPResult::Error().
311 // FIXME: Add statistics about the number of ambiguous statements encountered
312 // and how they were resolved (number of declarations+number of expressions).
314 // Ok, we have a simple-type-specifier/typename-specifier followed by a '('.
315 // We need tentative parsing...
317 TentativeParsingAction PA(*this);
319 // type-specifier-seq
320 if (Tok.is(tok::kw_typeof))
321 TryParseTypeofSpecifier();
325 if (getLang().ObjC1 && Tok.is(tok::less))
326 TryParseProtocolQualifiers();
329 assert(Tok.is(tok::l_paren) && "Expected '('");
332 TPR = TryParseDeclarator(true/*mayBeAbstract*/, false/*mayHaveIdentifier*/);
334 // In case of an error, let the declaration parsing code handle it.
335 if (TPR == TPResult::Error())
336 TPR = TPResult::True();
338 if (TPR == TPResult::Ambiguous()) {
339 // We are supposed to be inside parens, so if after the abstract declarator
340 // we encounter a ')' this is a type-id, otherwise it's an expression.
341 if (Context == TypeIdInParens && Tok.is(tok::r_paren)) {
342 TPR = TPResult::True();
345 // We are supposed to be inside a template argument, so if after
346 // the abstract declarator we encounter a '>', '>>' (in C++0x), or
347 // ',', this is a type-id. Otherwise, it's an expression.
348 } else if (Context == TypeIdAsTemplateArgument &&
349 (Tok.is(tok::greater) || Tok.is(tok::comma) ||
350 (getLang().CPlusPlus0x && Tok.is(tok::greatergreater)))) {
351 TPR = TPResult::True();
355 TPR = TPResult::False();
360 assert(TPR == TPResult::True() || TPR == TPResult::False());
361 return TPR == TPResult::True();
364 /// isCXX0XAttributeSpecifier - returns true if this is a C++0x
365 /// attribute-specifier. By default, unless in Obj-C++, only a cursory check is
366 /// performed that will simply return true if a [[ is seen. Currently C++ has no
367 /// syntactical ambiguities from this check, but it may inhibit error recovery.
368 /// If CheckClosing is true, a check is made for closing ]] brackets.
370 /// If given, After is set to the token after the attribute-specifier so that
371 /// appropriate parsing decisions can be made; it is left untouched if false is
374 /// FIXME: If an error is in the closing ]] brackets, the program assumes
375 /// the absence of an attribute-specifier, which can cause very yucky errors
378 /// [C++0x] attribute-specifier:
379 /// '[' '[' attribute-list ']' ']'
380 /// alignment-specifier
382 /// [C++0x] attribute-list:
384 /// attribute-list ',' attribute[opt]
386 /// [C++0x] attribute:
387 /// attribute-token attribute-argument-clause[opt]
389 /// [C++0x] attribute-token:
391 /// attribute-scoped-token
393 /// [C++0x] attribute-scoped-token:
394 /// attribute-namespace '::' identifier
396 /// [C++0x] attribute-namespace:
399 /// [C++0x] attribute-argument-clause:
400 /// '(' balanced-token-seq ')'
402 /// [C++0x] balanced-token-seq:
404 /// balanced-token-seq balanced-token
406 /// [C++0x] balanced-token:
407 /// '(' balanced-token-seq ')'
408 /// '[' balanced-token-seq ']'
409 /// '{' balanced-token-seq '}'
410 /// any token but '(', ')', '[', ']', '{', or '}'
411 bool Parser::isCXX0XAttributeSpecifier (bool CheckClosing,
412 tok::TokenKind *After) {
413 if (Tok.is(tok::kw_alignas))
416 if (Tok.isNot(tok::l_square) || NextToken().isNot(tok::l_square))
419 // No tentative parsing if we don't need to look for ]]
420 if (!CheckClosing && !getLang().ObjC1)
423 struct TentativeReverter {
424 TentativeParsingAction PA;
426 TentativeReverter (Parser& P)
429 ~TentativeReverter () {
434 // Opening brackets were checked for above.
438 // SkipUntil will handle balanced tokens, which are guaranteed in attributes.
439 SkipUntil(tok::r_square, false);
441 if (Tok.isNot(tok::r_square))
446 *After = Tok.getKind();
452 /// direct-declarator
453 /// ptr-operator declarator
455 /// direct-declarator:
457 /// direct-declarator '(' parameter-declaration-clause ')'
458 /// cv-qualifier-seq[opt] exception-specification[opt]
459 /// direct-declarator '[' constant-expression[opt] ']'
460 /// '(' declarator ')'
461 /// [GNU] '(' attributes declarator ')'
463 /// abstract-declarator:
464 /// ptr-operator abstract-declarator[opt]
465 /// direct-abstract-declarator
468 /// direct-abstract-declarator:
469 /// direct-abstract-declarator[opt]
470 /// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
471 /// exception-specification[opt]
472 /// direct-abstract-declarator[opt] '[' constant-expression[opt] ']'
473 /// '(' abstract-declarator ')'
476 /// '*' cv-qualifier-seq[opt]
478 /// [C++0x] '&&' [TODO]
479 /// '::'[opt] nested-name-specifier '*' cv-qualifier-seq[opt]
481 /// cv-qualifier-seq:
482 /// cv-qualifier cv-qualifier-seq[opt]
489 /// '...'[opt] id-expression
493 /// qualified-id [TODO]
497 /// operator-function-id [TODO]
498 /// conversion-function-id [TODO]
499 /// '~' class-name [TODO]
500 /// template-id [TODO]
502 Parser::TPResult Parser::TryParseDeclarator(bool mayBeAbstract,
503 bool mayHaveIdentifier) {
506 // ptr-operator declarator
509 if (Tok.is(tok::coloncolon) || Tok.is(tok::identifier))
510 if (TryAnnotateCXXScopeToken(true))
511 return TPResult::Error();
513 if (Tok.is(tok::star) || Tok.is(tok::amp) || Tok.is(tok::caret) ||
514 Tok.is(tok::ampamp) ||
515 (Tok.is(tok::annot_cxxscope) && NextToken().is(tok::star))) {
518 while (Tok.is(tok::kw_const) ||
519 Tok.is(tok::kw_volatile) ||
520 Tok.is(tok::kw_restrict))
527 // direct-declarator:
528 // direct-abstract-declarator:
529 if (Tok.is(tok::ellipsis))
532 if ((Tok.is(tok::identifier) ||
533 (Tok.is(tok::annot_cxxscope) && NextToken().is(tok::identifier))) &&
536 if (Tok.is(tok::annot_cxxscope))
539 } else if (Tok.is(tok::l_paren)) {
542 (Tok.is(tok::r_paren) || // 'int()' is a function.
543 Tok.is(tok::ellipsis) || // 'int(...)' is a function.
544 isDeclarationSpecifier())) { // 'int(int)' is a function.
545 // '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
546 // exception-specification[opt]
547 TPResult TPR = TryParseFunctionDeclarator();
548 if (TPR != TPResult::Ambiguous())
551 // '(' declarator ')'
552 // '(' attributes declarator ')'
553 // '(' abstract-declarator ')'
554 if (Tok.is(tok::kw___attribute) ||
555 Tok.is(tok::kw___declspec) ||
556 Tok.is(tok::kw___cdecl) ||
557 Tok.is(tok::kw___stdcall) ||
558 Tok.is(tok::kw___fastcall) ||
559 Tok.is(tok::kw___thiscall) ||
560 Tok.is(tok::kw___unaligned))
561 return TPResult::True(); // attributes indicate declaration
562 TPResult TPR = TryParseDeclarator(mayBeAbstract, mayHaveIdentifier);
563 if (TPR != TPResult::Ambiguous())
565 if (Tok.isNot(tok::r_paren))
566 return TPResult::False();
569 } else if (!mayBeAbstract) {
570 return TPResult::False();
574 TPResult TPR(TPResult::Ambiguous());
576 // abstract-declarator: ...
577 if (Tok.is(tok::ellipsis))
580 if (Tok.is(tok::l_paren)) {
581 // Check whether we have a function declarator or a possible ctor-style
582 // initializer that follows the declarator. Note that ctor-style
583 // initializers are not possible in contexts where abstract declarators
585 if (!mayBeAbstract && !isCXXFunctionDeclarator(false/*warnIfAmbiguous*/))
588 // direct-declarator '(' parameter-declaration-clause ')'
589 // cv-qualifier-seq[opt] exception-specification[opt]
591 TPR = TryParseFunctionDeclarator();
592 } else if (Tok.is(tok::l_square)) {
593 // direct-declarator '[' constant-expression[opt] ']'
594 // direct-abstract-declarator[opt] '[' constant-expression[opt] ']'
595 TPR = TryParseBracketDeclarator();
600 if (TPR != TPResult::Ambiguous())
604 return TPResult::Ambiguous();
608 Parser::isExpressionOrTypeSpecifierSimple(tok::TokenKind Kind) {
610 // Obviously starts an expression.
611 case tok::numeric_constant:
612 case tok::char_constant:
613 case tok::wide_char_constant:
614 case tok::utf16_char_constant:
615 case tok::utf32_char_constant:
616 case tok::string_literal:
617 case tok::wide_string_literal:
618 case tok::utf8_string_literal:
619 case tok::utf16_string_literal:
620 case tok::utf32_string_literal:
629 case tok::minusminus:
633 case tok::kw___func__:
634 case tok::kw_const_cast:
636 case tok::kw_dynamic_cast:
639 case tok::kw_operator:
640 case tok::kw_reinterpret_cast:
641 case tok::kw_static_cast:
646 case tok::kw_alignof:
647 case tok::kw_noexcept:
648 case tok::kw_nullptr:
650 case tok::kw___alignof:
651 case tok::kw___builtin_choose_expr:
652 case tok::kw___builtin_offsetof:
653 case tok::kw___builtin_types_compatible_p:
654 case tok::kw___builtin_va_arg:
657 case tok::kw___FUNCTION__:
658 case tok::kw___PRETTY_FUNCTION__:
659 case tok::kw___has_nothrow_assign:
660 case tok::kw___has_nothrow_copy:
661 case tok::kw___has_nothrow_constructor:
662 case tok::kw___has_trivial_assign:
663 case tok::kw___has_trivial_copy:
664 case tok::kw___has_trivial_constructor:
665 case tok::kw___has_trivial_destructor:
666 case tok::kw___has_virtual_destructor:
667 case tok::kw___is_abstract:
668 case tok::kw___is_base_of:
669 case tok::kw___is_class:
670 case tok::kw___is_convertible_to:
671 case tok::kw___is_empty:
672 case tok::kw___is_enum:
673 case tok::kw___is_literal:
674 case tok::kw___is_literal_type:
675 case tok::kw___is_pod:
676 case tok::kw___is_polymorphic:
677 case tok::kw___is_trivial:
678 case tok::kw___is_trivially_copyable:
679 case tok::kw___is_union:
680 case tok::kw___uuidof:
681 return TPResult::True();
683 // Obviously starts a type-specifier-seq:
692 case tok::kw___int64:
693 case tok::kw_restrict:
698 case tok::kw_unsigned:
700 case tok::kw_volatile:
702 case tok::kw__Complex:
704 case tok::kw_typename:
705 case tok::kw_wchar_t:
706 case tok::kw_char16_t:
707 case tok::kw_char32_t:
708 case tok::kw_decltype:
709 case tok::kw___underlying_type:
710 case tok::kw_thread_local:
711 case tok::kw__Decimal32:
712 case tok::kw__Decimal64:
713 case tok::kw__Decimal128:
714 case tok::kw___thread:
716 case tok::kw___cdecl:
717 case tok::kw___stdcall:
718 case tok::kw___fastcall:
719 case tok::kw___thiscall:
720 case tok::kw___unaligned:
721 case tok::kw___vector:
722 case tok::kw___pixel:
723 case tok::kw__Atomic:
724 return TPResult::False();
730 return TPResult::Ambiguous();
733 /// isCXXDeclarationSpecifier - Returns TPResult::True() if it is a declaration
734 /// specifier, TPResult::False() if it is not, TPResult::Ambiguous() if it could
735 /// be either a decl-specifier or a function-style cast, and TPResult::Error()
736 /// if a parsing error was found and reported.
739 /// storage-class-specifier
741 /// function-specifier
744 /// [C++0x] 'constexpr'
745 /// [GNU] attributes declaration-specifiers[opt]
747 /// storage-class-specifier:
755 /// function-specifier:
764 /// simple-type-specifier
767 /// elaborated-type-specifier
768 /// typename-specifier
771 /// simple-type-specifier:
772 /// '::'[opt] nested-name-specifier[opt] type-name
773 /// '::'[opt] nested-name-specifier 'template'
774 /// simple-template-id [TODO]
786 /// [GNU] typeof-specifier
788 /// [C++0x] 'auto' [TODO]
789 /// [C++0x] 'decltype' ( expression )
796 /// elaborated-type-specifier:
797 /// class-key '::'[opt] nested-name-specifier[opt] identifier
798 /// class-key '::'[opt] nested-name-specifier[opt] 'template'[opt]
799 /// simple-template-id
800 /// 'enum' '::'[opt] nested-name-specifier[opt] identifier
806 /// 'enum' identifier[opt] '{' enumerator-list[opt] '}'
807 /// 'enum' identifier[opt] '{' enumerator-list ',' '}'
810 /// class-head '{' member-specification[opt] '}'
813 /// class-key identifier[opt] base-clause[opt]
814 /// class-key nested-name-specifier identifier base-clause[opt]
815 /// class-key nested-name-specifier[opt] simple-template-id
828 Parser::TPResult Parser::isCXXDeclarationSpecifier() {
829 switch (Tok.getKind()) {
830 case tok::identifier: // foo::bar
831 // Check for need to substitute AltiVec __vector keyword
832 // for "vector" identifier.
833 if (TryAltiVecVectorToken())
834 return TPResult::True();
836 case tok::kw_typename: // typename T::type
837 // Annotate typenames and C++ scope specifiers. If we get one, just
838 // recurse to handle whatever we get.
839 if (TryAnnotateTypeOrScopeToken())
840 return TPResult::Error();
841 if (Tok.is(tok::identifier))
842 return TPResult::False();
843 return isCXXDeclarationSpecifier();
845 case tok::coloncolon: { // ::foo::bar
846 const Token &Next = NextToken();
847 if (Next.is(tok::kw_new) || // ::new
848 Next.is(tok::kw_delete)) // ::delete
849 return TPResult::False();
851 // Annotate typenames and C++ scope specifiers. If we get one, just
852 // recurse to handle whatever we get.
853 if (TryAnnotateTypeOrScopeToken())
854 return TPResult::Error();
855 return isCXXDeclarationSpecifier();
859 // storage-class-specifier
861 // function-specifier
866 case tok::kw_typedef:
867 case tok::kw_constexpr:
868 // storage-class-specifier
869 case tok::kw_register:
872 case tok::kw_mutable:
874 case tok::kw___thread:
875 // function-specifier
877 case tok::kw_virtual:
878 case tok::kw_explicit:
881 case tok::kw___module_private__:
884 // simple-type-specifier
887 // elaborated-type-specifier
888 // typename-specifier
892 // elaborated-type-specifier
900 case tok::kw_volatile:
903 case tok::kw_restrict:
904 case tok::kw__Complex:
905 case tok::kw___attribute:
906 return TPResult::True();
909 case tok::kw___declspec:
910 case tok::kw___cdecl:
911 case tok::kw___stdcall:
912 case tok::kw___fastcall:
913 case tok::kw___thiscall:
915 case tok::kw___ptr64:
916 case tok::kw___ptr32:
917 case tok::kw___forceinline:
918 case tok::kw___unaligned:
919 return TPResult::True();
922 case tok::kw___pascal:
923 return TPResult::True();
926 case tok::kw___vector:
927 return TPResult::True();
929 case tok::annot_template_id: {
930 TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok);
931 if (TemplateId->Kind != TNK_Type_template)
932 return TPResult::False();
934 AnnotateTemplateIdTokenAsType();
935 assert(Tok.is(tok::annot_typename));
939 case tok::annot_cxxscope: // foo::bar or ::foo::bar, but already parsed
940 // We've already annotated a scope; try to annotate a type.
941 if (TryAnnotateTypeOrScopeToken())
942 return TPResult::Error();
943 if (!Tok.is(tok::annot_typename))
944 return TPResult::False();
945 // If that succeeded, fallthrough into the generic simple-type-id case.
947 // The ambiguity resides in a simple-type-specifier/typename-specifier
948 // followed by a '('. The '(' could either be the start of:
950 // direct-declarator:
951 // '(' declarator ')'
953 // direct-abstract-declarator:
954 // '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
955 // exception-specification[opt]
956 // '(' abstract-declarator ')'
958 // or part of a function-style cast expression:
960 // simple-type-specifier '(' expression-list[opt] ')'
963 // simple-type-specifier:
965 case tok::annot_typename:
967 // In Objective-C, we might have a protocol-qualified type.
968 if (getLang().ObjC1 && NextToken().is(tok::less)) {
969 // Tentatively parse the
970 TentativeParsingAction PA(*this);
971 ConsumeToken(); // The type token
973 TPResult TPR = TryParseProtocolQualifiers();
974 bool isFollowedByParen = Tok.is(tok::l_paren);
978 if (TPR == TPResult::Error())
979 return TPResult::Error();
981 if (isFollowedByParen)
982 return TPResult::Ambiguous();
984 return TPResult::True();
988 case tok::kw_wchar_t:
989 case tok::kw_char16_t:
990 case tok::kw_char32_t:
995 case tok::kw___int64:
997 case tok::kw_unsigned:
1000 case tok::kw_double:
1002 if (NextToken().is(tok::l_paren))
1003 return TPResult::Ambiguous();
1005 if (isStartOfObjCClassMessageMissingOpenBracket())
1006 return TPResult::False();
1008 return TPResult::True();
1010 // GNU typeof support.
1011 case tok::kw_typeof: {
1012 if (NextToken().isNot(tok::l_paren))
1013 return TPResult::True();
1015 TentativeParsingAction PA(*this);
1017 TPResult TPR = TryParseTypeofSpecifier();
1018 bool isFollowedByParen = Tok.is(tok::l_paren);
1022 if (TPR == TPResult::Error())
1023 return TPResult::Error();
1025 if (isFollowedByParen)
1026 return TPResult::Ambiguous();
1028 return TPResult::True();
1031 // C++0x decltype support.
1032 case tok::kw_decltype:
1033 return TPResult::True();
1035 // C++0x type traits support
1036 case tok::kw___underlying_type:
1037 return TPResult::True();
1040 case tok::kw__Atomic:
1041 return TPResult::True();
1044 return TPResult::False();
1048 /// [GNU] typeof-specifier:
1049 /// 'typeof' '(' expressions ')'
1050 /// 'typeof' '(' type-name ')'
1052 Parser::TPResult Parser::TryParseTypeofSpecifier() {
1053 assert(Tok.is(tok::kw_typeof) && "Expected 'typeof'!");
1056 assert(Tok.is(tok::l_paren) && "Expected '('");
1057 // Parse through the parens after 'typeof'.
1059 if (!SkipUntil(tok::r_paren))
1060 return TPResult::Error();
1062 return TPResult::Ambiguous();
1065 /// [ObjC] protocol-qualifiers:
1066 //// '<' identifier-list '>'
1067 Parser::TPResult Parser::TryParseProtocolQualifiers() {
1068 assert(Tok.is(tok::less) && "Expected '<' for qualifier list");
1071 if (Tok.isNot(tok::identifier))
1072 return TPResult::Error();
1075 if (Tok.is(tok::comma)) {
1080 if (Tok.is(tok::greater)) {
1082 return TPResult::Ambiguous();
1086 return TPResult::Error();
1089 Parser::TPResult Parser::TryParseDeclarationSpecifier() {
1090 TPResult TPR = isCXXDeclarationSpecifier();
1091 if (TPR != TPResult::Ambiguous())
1094 if (Tok.is(tok::kw_typeof))
1095 TryParseTypeofSpecifier();
1099 if (getLang().ObjC1 && Tok.is(tok::less))
1100 TryParseProtocolQualifiers();
1103 assert(Tok.is(tok::l_paren) && "Expected '('!");
1104 return TPResult::Ambiguous();
1107 /// isCXXFunctionDeclarator - Disambiguates between a function declarator or
1108 /// a constructor-style initializer, when parsing declaration statements.
1109 /// Returns true for function declarator and false for constructor-style
1111 /// If during the disambiguation process a parsing error is encountered,
1112 /// the function returns true to let the declaration parsing code handle it.
1114 /// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
1115 /// exception-specification[opt]
1117 bool Parser::isCXXFunctionDeclarator(bool warnIfAmbiguous) {
1120 // The ambiguity arising from the similarity between a function-style cast and
1121 // a declaration mentioned in 6.8 can also occur in the context of a
1122 // declaration. In that context, the choice is between a function declaration
1123 // with a redundant set of parentheses around a parameter name and an object
1124 // declaration with a function-style cast as the initializer. Just as for the
1125 // ambiguities mentioned in 6.8, the resolution is to consider any construct
1126 // that could possibly be a declaration a declaration.
1128 TentativeParsingAction PA(*this);
1131 TPResult TPR = TryParseParameterDeclarationClause();
1132 if (TPR == TPResult::Ambiguous() && Tok.isNot(tok::r_paren))
1133 TPR = TPResult::False();
1135 SourceLocation TPLoc = Tok.getLocation();
1138 // In case of an error, let the declaration parsing code handle it.
1139 if (TPR == TPResult::Error())
1142 if (TPR == TPResult::Ambiguous()) {
1143 // Function declarator has precedence over constructor-style initializer.
1144 // Emit a warning just in case the author intended a variable definition.
1145 if (warnIfAmbiguous)
1146 Diag(Tok, diag::warn_parens_disambiguated_as_function_decl)
1147 << SourceRange(Tok.getLocation(), TPLoc);
1151 return TPR == TPResult::True();
1154 /// parameter-declaration-clause:
1155 /// parameter-declaration-list[opt] '...'[opt]
1156 /// parameter-declaration-list ',' '...'
1158 /// parameter-declaration-list:
1159 /// parameter-declaration
1160 /// parameter-declaration-list ',' parameter-declaration
1162 /// parameter-declaration:
1163 /// decl-specifier-seq declarator attributes[opt]
1164 /// decl-specifier-seq declarator attributes[opt] '=' assignment-expression
1165 /// decl-specifier-seq abstract-declarator[opt] attributes[opt]
1166 /// decl-specifier-seq abstract-declarator[opt] attributes[opt]
1167 /// '=' assignment-expression
1169 Parser::TPResult Parser::TryParseParameterDeclarationClause() {
1171 if (Tok.is(tok::r_paren))
1172 return TPResult::True();
1174 // parameter-declaration-list[opt] '...'[opt]
1175 // parameter-declaration-list ',' '...'
1177 // parameter-declaration-list:
1178 // parameter-declaration
1179 // parameter-declaration-list ',' parameter-declaration
1183 if (Tok.is(tok::ellipsis)) {
1185 return TPResult::True(); // '...' is a sign of a function declarator.
1188 ParsedAttributes attrs(AttrFactory);
1189 MaybeParseMicrosoftAttributes(attrs);
1191 // decl-specifier-seq
1192 TPResult TPR = TryParseDeclarationSpecifier();
1193 if (TPR != TPResult::Ambiguous())
1197 // abstract-declarator[opt]
1198 TPR = TryParseDeclarator(true/*mayBeAbstract*/);
1199 if (TPR != TPResult::Ambiguous())
1202 // [GNU] attributes[opt]
1203 if (Tok.is(tok::kw___attribute))
1204 return TPResult::True();
1206 if (Tok.is(tok::equal)) {
1207 // '=' assignment-expression
1208 // Parse through assignment-expression.
1209 tok::TokenKind StopToks[2] ={ tok::comma, tok::r_paren };
1210 if (!SkipUntil(StopToks, 2, true/*StopAtSemi*/, true/*DontConsume*/))
1211 return TPResult::Error();
1214 if (Tok.is(tok::ellipsis)) {
1216 return TPResult::True(); // '...' is a sign of a function declarator.
1219 if (Tok.isNot(tok::comma))
1221 ConsumeToken(); // the comma.
1224 return TPResult::Ambiguous();
1227 /// TryParseFunctionDeclarator - We parsed a '(' and we want to try to continue
1228 /// parsing as a function declarator.
1229 /// If TryParseFunctionDeclarator fully parsed the function declarator, it will
1230 /// return TPResult::Ambiguous(), otherwise it will return either False() or
1233 /// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
1234 /// exception-specification[opt]
1236 /// exception-specification:
1237 /// 'throw' '(' type-id-list[opt] ')'
1239 Parser::TPResult Parser::TryParseFunctionDeclarator() {
1241 // The '(' is already parsed.
1243 TPResult TPR = TryParseParameterDeclarationClause();
1244 if (TPR == TPResult::Ambiguous() && Tok.isNot(tok::r_paren))
1245 TPR = TPResult::False();
1247 if (TPR == TPResult::False() || TPR == TPResult::Error())
1250 // Parse through the parens.
1251 if (!SkipUntil(tok::r_paren))
1252 return TPResult::Error();
1255 while (Tok.is(tok::kw_const) ||
1256 Tok.is(tok::kw_volatile) ||
1257 Tok.is(tok::kw_restrict) )
1260 // ref-qualifier[opt]
1261 if (Tok.is(tok::amp) || Tok.is(tok::ampamp))
1264 // exception-specification
1265 if (Tok.is(tok::kw_throw)) {
1267 if (Tok.isNot(tok::l_paren))
1268 return TPResult::Error();
1270 // Parse through the parens after 'throw'.
1272 if (!SkipUntil(tok::r_paren))
1273 return TPResult::Error();
1275 if (Tok.is(tok::kw_noexcept)) {
1277 // Possibly an expression as well.
1278 if (Tok.is(tok::l_paren)) {
1279 // Find the matching rparen.
1281 if (!SkipUntil(tok::r_paren))
1282 return TPResult::Error();
1286 return TPResult::Ambiguous();
1289 /// '[' constant-expression[opt] ']'
1291 Parser::TPResult Parser::TryParseBracketDeclarator() {
1293 if (!SkipUntil(tok::r_square))
1294 return TPResult::Error();
1296 return TPResult::Ambiguous();