| //===--- ParseTentative.cpp - Ambiguity Resolution Parsing ----------------===// |
| // |
| // The LLVM Compiler Infrastructure |
| // |
| // This file is distributed under the University of Illinois Open Source |
| // License. See LICENSE.TXT for details. |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the tentative parsing portions of the Parser |
| // interfaces, for ambiguity resolution. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Parse/Parser.h" |
| #include "clang/Parse/ParseDiagnostic.h" |
| using namespace clang; |
| |
| /// isCXXDeclarationStatement - C++-specialized function that disambiguates |
| /// between a declaration or an expression statement, when parsing function |
| /// bodies. Returns true for declaration, false for expression. |
| /// |
| /// declaration-statement: |
| /// block-declaration |
| /// |
| /// block-declaration: |
| /// simple-declaration |
| /// asm-definition |
| /// namespace-alias-definition |
| /// using-declaration |
| /// using-directive |
| /// [C++0x] static_assert-declaration |
| /// |
| /// asm-definition: |
| /// 'asm' '(' string-literal ')' ';' |
| /// |
| /// namespace-alias-definition: |
| /// 'namespace' identifier = qualified-namespace-specifier ';' |
| /// |
| /// using-declaration: |
| /// 'using' typename[opt] '::'[opt] nested-name-specifier |
| /// unqualified-id ';' |
| /// 'using' '::' unqualified-id ; |
| /// |
| /// using-directive: |
| /// 'using' 'namespace' '::'[opt] nested-name-specifier[opt] |
| /// namespace-name ';' |
| /// |
| bool Parser::isCXXDeclarationStatement() { |
| switch (Tok.getKind()) { |
| // asm-definition |
| case tok::kw_asm: |
| // namespace-alias-definition |
| case tok::kw_namespace: |
| // using-declaration |
| // using-directive |
| case tok::kw_using: |
| return true; |
| case tok::kw_static_assert: |
| // static_assert-declaration |
| return true; |
| default: |
| // simple-declaration |
| return isCXXSimpleDeclaration(); |
| } |
| } |
| |
| /// isCXXSimpleDeclaration - C++-specialized function that disambiguates |
| /// between a simple-declaration or an expression-statement. |
| /// If during the disambiguation process a parsing error is encountered, |
| /// the function returns true to let the declaration parsing code handle it. |
| /// Returns false if the statement is disambiguated as expression. |
| /// |
| /// simple-declaration: |
| /// decl-specifier-seq init-declarator-list[opt] ';' |
| /// |
| bool Parser::isCXXSimpleDeclaration() { |
| // C++ 6.8p1: |
| // There is an ambiguity in the grammar involving expression-statements and |
| // declarations: An expression-statement with a function-style explicit type |
| // conversion (5.2.3) as its leftmost subexpression can be indistinguishable |
| // from a declaration where the first declarator starts with a '('. In those |
| // cases the statement is a declaration. [Note: To disambiguate, the whole |
| // statement might have to be examined to determine if it is an |
| // expression-statement or a declaration]. |
| |
| // C++ 6.8p3: |
| // The disambiguation is purely syntactic; that is, the meaning of the names |
| // occurring in such a statement, beyond whether they are type-names or not, |
| // is not generally used in or changed by the disambiguation. Class |
| // templates are instantiated as necessary to determine if a qualified name |
| // is a type-name. Disambiguation precedes parsing, and a statement |
| // disambiguated as a declaration may be an ill-formed declaration. |
| |
| // We don't have to parse all of the decl-specifier-seq part. There's only |
| // an ambiguity if the first decl-specifier is |
| // simple-type-specifier/typename-specifier followed by a '(', which may |
| // indicate a function-style cast expression. |
| // isCXXDeclarationSpecifier will return TPResult::Ambiguous() only in such |
| // a case. |
| |
| TPResult TPR = isCXXDeclarationSpecifier(); |
| if (TPR != TPResult::Ambiguous()) |
| return TPR != TPResult::False(); // Returns true for TPResult::True() or |
| // TPResult::Error(). |
| |
| // FIXME: Add statistics about the number of ambiguous statements encountered |
| // and how they were resolved (number of declarations+number of expressions). |
| |
| // Ok, we have a simple-type-specifier/typename-specifier followed by a '('. |
| // We need tentative parsing... |
| |
| TentativeParsingAction PA(*this); |
| |
| TPR = TryParseSimpleDeclaration(); |
| SourceLocation TentativeParseLoc = Tok.getLocation(); |
| |
| PA.Revert(); |
| |
| // In case of an error, let the declaration parsing code handle it. |
| if (TPR == TPResult::Error()) |
| return true; |
| |
| // Declarations take precedence over expressions. |
| if (TPR == TPResult::Ambiguous()) |
| TPR = TPResult::True(); |
| |
| assert(TPR == TPResult::True() || TPR == TPResult::False()); |
| return TPR == TPResult::True(); |
| } |
| |
| /// simple-declaration: |
| /// decl-specifier-seq init-declarator-list[opt] ';' |
| /// |
| Parser::TPResult Parser::TryParseSimpleDeclaration() { |
| // We know that we have a simple-type-specifier/typename-specifier followed |
| // by a '('. |
| assert(isCXXDeclarationSpecifier() == TPResult::Ambiguous()); |
| |
| if (Tok.is(tok::kw_typeof)) |
| TryParseTypeofSpecifier(); |
| else |
| ConsumeToken(); |
| |
| assert(Tok.is(tok::l_paren) && "Expected '('"); |
| |
| TPResult TPR = TryParseInitDeclaratorList(); |
| if (TPR != TPResult::Ambiguous()) |
| return TPR; |
| |
| if (Tok.isNot(tok::semi)) |
| return TPResult::False(); |
| |
| return TPResult::Ambiguous(); |
| } |
| |
| /// init-declarator-list: |
| /// init-declarator |
| /// init-declarator-list ',' init-declarator |
| /// |
| /// init-declarator: |
| /// declarator initializer[opt] |
| /// [GNU] declarator simple-asm-expr[opt] attributes[opt] initializer[opt] |
| /// |
| /// initializer: |
| /// '=' initializer-clause |
| /// '(' expression-list ')' |
| /// |
| /// initializer-clause: |
| /// assignment-expression |
| /// '{' initializer-list ','[opt] '}' |
| /// '{' '}' |
| /// |
| Parser::TPResult Parser::TryParseInitDeclaratorList() { |
| // GCC only examines the first declarator for disambiguation: |
| // i.e: |
| // int(x), ++x; // GCC regards it as ill-formed declaration. |
| // |
| // Comeau and MSVC will regard the above statement as correct expression. |
| // Clang examines all of the declarators and also regards the above statement |
| // as correct expression. |
| |
| while (1) { |
| // declarator |
| TPResult TPR = TryParseDeclarator(false/*mayBeAbstract*/); |
| if (TPR != TPResult::Ambiguous()) |
| return TPR; |
| |
| // [GNU] simple-asm-expr[opt] attributes[opt] |
| if (Tok.is(tok::kw_asm) || Tok.is(tok::kw___attribute)) |
| return TPResult::True(); |
| |
| // initializer[opt] |
| if (Tok.is(tok::l_paren)) { |
| // Parse through the parens. |
| ConsumeParen(); |
| if (!SkipUntil(tok::r_paren)) |
| return TPResult::Error(); |
| } else if (Tok.is(tok::equal)) { |
| // MSVC won't examine the rest of declarators if '=' is encountered, it |
| // will conclude that it is a declaration. |
| // Comeau and Clang will examine the rest of declarators. |
| // Note that "int(x) = {0}, ++x;" will be interpreted as ill-formed |
| // expression. |
| // |
| // Parse through the initializer-clause. |
| SkipUntil(tok::comma, true/*StopAtSemi*/, true/*DontConsume*/); |
| } |
| |
| if (Tok.isNot(tok::comma)) |
| break; |
| ConsumeToken(); // the comma. |
| } |
| |
| return TPResult::Ambiguous(); |
| } |
| |
| /// isCXXConditionDeclaration - Disambiguates between a declaration or an |
| /// expression for a condition of a if/switch/while/for statement. |
| /// If during the disambiguation process a parsing error is encountered, |
| /// the function returns true to let the declaration parsing code handle it. |
| /// |
| /// condition: |
| /// expression |
| /// type-specifier-seq declarator '=' assignment-expression |
| /// [GNU] type-specifier-seq declarator simple-asm-expr[opt] attributes[opt] |
| /// '=' assignment-expression |
| /// |
| bool Parser::isCXXConditionDeclaration() { |
| TPResult TPR = isCXXDeclarationSpecifier(); |
| if (TPR != TPResult::Ambiguous()) |
| return TPR != TPResult::False(); // Returns true for TPResult::True() or |
| // TPResult::Error(). |
| |
| // FIXME: Add statistics about the number of ambiguous statements encountered |
| // and how they were resolved (number of declarations+number of expressions). |
| |
| // Ok, we have a simple-type-specifier/typename-specifier followed by a '('. |
| // We need tentative parsing... |
| |
| TentativeParsingAction PA(*this); |
| |
| // type-specifier-seq |
| if (Tok.is(tok::kw_typeof)) |
| TryParseTypeofSpecifier(); |
| else |
| ConsumeToken(); |
| assert(Tok.is(tok::l_paren) && "Expected '('"); |
| |
| // declarator |
| TPR = TryParseDeclarator(false/*mayBeAbstract*/); |
| |
| // In case of an error, let the declaration parsing code handle it. |
| if (TPR == TPResult::Error()) |
| TPR = TPResult::True(); |
| |
| if (TPR == TPResult::Ambiguous()) { |
| // '=' |
| // [GNU] simple-asm-expr[opt] attributes[opt] |
| if (Tok.is(tok::equal) || |
| Tok.is(tok::kw_asm) || Tok.is(tok::kw___attribute)) |
| TPR = TPResult::True(); |
| else |
| TPR = TPResult::False(); |
| } |
| |
| PA.Revert(); |
| |
| assert(TPR == TPResult::True() || TPR == TPResult::False()); |
| return TPR == TPResult::True(); |
| } |
| |
| /// \brief Determine whether the next set of tokens contains a type-id. |
| /// |
| /// The context parameter states what context we're parsing right |
| /// now, which affects how this routine copes with the token |
| /// following the type-id. If the context is TypeIdInParens, we have |
| /// already parsed the '(' and we will cease lookahead when we hit |
| /// the corresponding ')'. If the context is |
| /// TypeIdAsTemplateArgument, we've already parsed the '<' or ',' |
| /// before this template argument, and will cease lookahead when we |
| /// hit a '>', '>>' (in C++0x), or ','. Returns true for a type-id |
| /// and false for an expression. If during the disambiguation |
| /// process a parsing error is encountered, the function returns |
| /// true to let the declaration parsing code handle it. |
| /// |
| /// type-id: |
| /// type-specifier-seq abstract-declarator[opt] |
| /// |
| bool Parser::isCXXTypeId(TentativeCXXTypeIdContext Context, bool &isAmbiguous) { |
| |
| isAmbiguous = false; |
| |
| // C++ 8.2p2: |
| // The ambiguity arising from the similarity between a function-style cast and |
| // a type-id can occur in different contexts. The ambiguity appears as a |
| // choice between a function-style cast expression and a declaration of a |
| // type. The resolution is that any construct that could possibly be a type-id |
| // in its syntactic context shall be considered a type-id. |
| |
| TPResult TPR = isCXXDeclarationSpecifier(); |
| if (TPR != TPResult::Ambiguous()) |
| return TPR != TPResult::False(); // Returns true for TPResult::True() or |
| // TPResult::Error(). |
| |
| // FIXME: Add statistics about the number of ambiguous statements encountered |
| // and how they were resolved (number of declarations+number of expressions). |
| |
| // Ok, we have a simple-type-specifier/typename-specifier followed by a '('. |
| // We need tentative parsing... |
| |
| TentativeParsingAction PA(*this); |
| |
| // type-specifier-seq |
| if (Tok.is(tok::kw_typeof)) |
| TryParseTypeofSpecifier(); |
| else |
| ConsumeToken(); |
| assert(Tok.is(tok::l_paren) && "Expected '('"); |
| |
| // declarator |
| TPR = TryParseDeclarator(true/*mayBeAbstract*/, false/*mayHaveIdentifier*/); |
| |
| // In case of an error, let the declaration parsing code handle it. |
| if (TPR == TPResult::Error()) |
| TPR = TPResult::True(); |
| |
| if (TPR == TPResult::Ambiguous()) { |
| // We are supposed to be inside parens, so if after the abstract declarator |
| // we encounter a ')' this is a type-id, otherwise it's an expression. |
| if (Context == TypeIdInParens && Tok.is(tok::r_paren)) { |
| TPR = TPResult::True(); |
| isAmbiguous = true; |
| |
| // We are supposed to be inside a template argument, so if after |
| // the abstract declarator we encounter a '>', '>>' (in C++0x), or |
| // ',', this is a type-id. Otherwise, it's an expression. |
| } else if (Context == TypeIdAsTemplateArgument && |
| (Tok.is(tok::greater) || Tok.is(tok::comma) || |
| (getLang().CPlusPlus0x && Tok.is(tok::greatergreater)))) { |
| TPR = TPResult::True(); |
| isAmbiguous = true; |
| |
| } else |
| TPR = TPResult::False(); |
| } |
| |
| PA.Revert(); |
| |
| assert(TPR == TPResult::True() || TPR == TPResult::False()); |
| return TPR == TPResult::True(); |
| } |
| |
| /// declarator: |
| /// direct-declarator |
| /// ptr-operator declarator |
| /// |
| /// direct-declarator: |
| /// declarator-id |
| /// direct-declarator '(' parameter-declaration-clause ')' |
| /// cv-qualifier-seq[opt] exception-specification[opt] |
| /// direct-declarator '[' constant-expression[opt] ']' |
| /// '(' declarator ')' |
| /// [GNU] '(' attributes declarator ')' |
| /// |
| /// abstract-declarator: |
| /// ptr-operator abstract-declarator[opt] |
| /// direct-abstract-declarator |
| /// |
| /// direct-abstract-declarator: |
| /// direct-abstract-declarator[opt] |
| /// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt] |
| /// exception-specification[opt] |
| /// direct-abstract-declarator[opt] '[' constant-expression[opt] ']' |
| /// '(' abstract-declarator ')' |
| /// |
| /// ptr-operator: |
| /// '*' cv-qualifier-seq[opt] |
| /// '&' |
| /// [C++0x] '&&' [TODO] |
| /// '::'[opt] nested-name-specifier '*' cv-qualifier-seq[opt] |
| /// |
| /// cv-qualifier-seq: |
| /// cv-qualifier cv-qualifier-seq[opt] |
| /// |
| /// cv-qualifier: |
| /// 'const' |
| /// 'volatile' |
| /// |
| /// declarator-id: |
| /// id-expression |
| /// |
| /// id-expression: |
| /// unqualified-id |
| /// qualified-id [TODO] |
| /// |
| /// unqualified-id: |
| /// identifier |
| /// operator-function-id [TODO] |
| /// conversion-function-id [TODO] |
| /// '~' class-name [TODO] |
| /// template-id [TODO] |
| /// |
| Parser::TPResult Parser::TryParseDeclarator(bool mayBeAbstract, |
| bool mayHaveIdentifier) { |
| // declarator: |
| // direct-declarator |
| // ptr-operator declarator |
| |
| while (1) { |
| if (Tok.is(tok::coloncolon) || Tok.is(tok::identifier)) |
| TryAnnotateCXXScopeToken(); |
| |
| if (Tok.is(tok::star) || Tok.is(tok::amp) || Tok.is(tok::caret) || |
| (Tok.is(tok::annot_cxxscope) && NextToken().is(tok::star))) { |
| // ptr-operator |
| ConsumeToken(); |
| while (Tok.is(tok::kw_const) || |
| Tok.is(tok::kw_volatile) || |
| Tok.is(tok::kw_restrict)) |
| ConsumeToken(); |
| } else { |
| break; |
| } |
| } |
| |
| // direct-declarator: |
| // direct-abstract-declarator: |
| |
| if (Tok.is(tok::identifier) && mayHaveIdentifier) { |
| // declarator-id |
| ConsumeToken(); |
| } else if (Tok.is(tok::l_paren)) { |
| ConsumeParen(); |
| if (mayBeAbstract && |
| (Tok.is(tok::r_paren) || // 'int()' is a function. |
| Tok.is(tok::ellipsis) || // 'int(...)' is a function. |
| isDeclarationSpecifier())) { // 'int(int)' is a function. |
| // '(' parameter-declaration-clause ')' cv-qualifier-seq[opt] |
| // exception-specification[opt] |
| TPResult TPR = TryParseFunctionDeclarator(); |
| if (TPR != TPResult::Ambiguous()) |
| return TPR; |
| } else { |
| // '(' declarator ')' |
| // '(' attributes declarator ')' |
| // '(' abstract-declarator ')' |
| if (Tok.is(tok::kw___attribute)) |
| return TPResult::True(); // attributes indicate declaration |
| TPResult TPR = TryParseDeclarator(mayBeAbstract, mayHaveIdentifier); |
| if (TPR != TPResult::Ambiguous()) |
| return TPR; |
| if (Tok.isNot(tok::r_paren)) |
| return TPResult::False(); |
| ConsumeParen(); |
| } |
| } else if (!mayBeAbstract) { |
| return TPResult::False(); |
| } |
| |
| while (1) { |
| TPResult TPR(TPResult::Ambiguous()); |
| |
| if (Tok.is(tok::l_paren)) { |
| // Check whether we have a function declarator or a possible ctor-style |
| // initializer that follows the declarator. Note that ctor-style |
| // initializers are not possible in contexts where abstract declarators |
| // are allowed. |
| if (!mayBeAbstract && !isCXXFunctionDeclarator(false/*warnIfAmbiguous*/)) |
| break; |
| |
| // direct-declarator '(' parameter-declaration-clause ')' |
| // cv-qualifier-seq[opt] exception-specification[opt] |
| ConsumeParen(); |
| TPR = TryParseFunctionDeclarator(); |
| } else if (Tok.is(tok::l_square)) { |
| // direct-declarator '[' constant-expression[opt] ']' |
| // direct-abstract-declarator[opt] '[' constant-expression[opt] ']' |
| TPR = TryParseBracketDeclarator(); |
| } else { |
| break; |
| } |
| |
| if (TPR != TPResult::Ambiguous()) |
| return TPR; |
| } |
| |
| return TPResult::Ambiguous(); |
| } |
| |
| /// isCXXDeclarationSpecifier - Returns TPResult::True() if it is a declaration |
| /// specifier, TPResult::False() if it is not, TPResult::Ambiguous() if it could |
| /// be either a decl-specifier or a function-style cast, and TPResult::Error() |
| /// if a parsing error was found and reported. |
| /// |
| /// decl-specifier: |
| /// storage-class-specifier |
| /// type-specifier |
| /// function-specifier |
| /// 'friend' |
| /// 'typedef' |
| /// [GNU] attributes declaration-specifiers[opt] |
| /// |
| /// storage-class-specifier: |
| /// 'register' |
| /// 'static' |
| /// 'extern' |
| /// 'mutable' |
| /// 'auto' |
| /// [GNU] '__thread' |
| /// |
| /// function-specifier: |
| /// 'inline' |
| /// 'virtual' |
| /// 'explicit' |
| /// |
| /// typedef-name: |
| /// identifier |
| /// |
| /// type-specifier: |
| /// simple-type-specifier |
| /// class-specifier |
| /// enum-specifier |
| /// elaborated-type-specifier |
| /// typename-specifier |
| /// cv-qualifier |
| /// |
| /// simple-type-specifier: |
| /// '::'[opt] nested-name-specifier[opt] type-name |
| /// '::'[opt] nested-name-specifier 'template' |
| /// simple-template-id [TODO] |
| /// 'char' |
| /// 'wchar_t' |
| /// 'bool' |
| /// 'short' |
| /// 'int' |
| /// 'long' |
| /// 'signed' |
| /// 'unsigned' |
| /// 'float' |
| /// 'double' |
| /// 'void' |
| /// [GNU] typeof-specifier |
| /// [GNU] '_Complex' |
| /// [C++0x] 'auto' [TODO] |
| /// |
| /// type-name: |
| /// class-name |
| /// enum-name |
| /// typedef-name |
| /// |
| /// elaborated-type-specifier: |
| /// class-key '::'[opt] nested-name-specifier[opt] identifier |
| /// class-key '::'[opt] nested-name-specifier[opt] 'template'[opt] |
| /// simple-template-id |
| /// 'enum' '::'[opt] nested-name-specifier[opt] identifier |
| /// |
| /// enum-name: |
| /// identifier |
| /// |
| /// enum-specifier: |
| /// 'enum' identifier[opt] '{' enumerator-list[opt] '}' |
| /// 'enum' identifier[opt] '{' enumerator-list ',' '}' |
| /// |
| /// class-specifier: |
| /// class-head '{' member-specification[opt] '}' |
| /// |
| /// class-head: |
| /// class-key identifier[opt] base-clause[opt] |
| /// class-key nested-name-specifier identifier base-clause[opt] |
| /// class-key nested-name-specifier[opt] simple-template-id |
| /// base-clause[opt] |
| /// |
| /// class-key: |
| /// 'class' |
| /// 'struct' |
| /// 'union' |
| /// |
| /// cv-qualifier: |
| /// 'const' |
| /// 'volatile' |
| /// [GNU] restrict |
| /// |
| Parser::TPResult Parser::isCXXDeclarationSpecifier() { |
| switch (Tok.getKind()) { |
| case tok::identifier: // foo::bar |
| case tok::kw_typename: // typename T::type |
| // Annotate typenames and C++ scope specifiers. If we get one, just |
| // recurse to handle whatever we get. |
| if (TryAnnotateTypeOrScopeToken()) |
| return isCXXDeclarationSpecifier(); |
| // Otherwise, not a typename. |
| return TPResult::False(); |
| |
| case tok::coloncolon: // ::foo::bar |
| if (NextToken().is(tok::kw_new) || // ::new |
| NextToken().is(tok::kw_delete)) // ::delete |
| return TPResult::False(); |
| |
| // Annotate typenames and C++ scope specifiers. If we get one, just |
| // recurse to handle whatever we get. |
| if (TryAnnotateTypeOrScopeToken()) |
| return isCXXDeclarationSpecifier(); |
| // Otherwise, not a typename. |
| return TPResult::False(); |
| |
| // decl-specifier: |
| // storage-class-specifier |
| // type-specifier |
| // function-specifier |
| // 'friend' |
| // 'typedef' |
| |
| case tok::kw_friend: |
| case tok::kw_typedef: |
| // storage-class-specifier |
| case tok::kw_register: |
| case tok::kw_static: |
| case tok::kw_extern: |
| case tok::kw_mutable: |
| case tok::kw_auto: |
| case tok::kw___thread: |
| // function-specifier |
| case tok::kw_inline: |
| case tok::kw_virtual: |
| case tok::kw_explicit: |
| |
| // type-specifier: |
| // simple-type-specifier |
| // class-specifier |
| // enum-specifier |
| // elaborated-type-specifier |
| // typename-specifier |
| // cv-qualifier |
| |
| // class-specifier |
| // elaborated-type-specifier |
| case tok::kw_class: |
| case tok::kw_struct: |
| case tok::kw_union: |
| // enum-specifier |
| case tok::kw_enum: |
| // cv-qualifier |
| case tok::kw_const: |
| case tok::kw_volatile: |
| |
| // GNU |
| case tok::kw_restrict: |
| case tok::kw__Complex: |
| case tok::kw___attribute: |
| return TPResult::True(); |
| |
| // Microsoft |
| case tok::kw___declspec: |
| case tok::kw___cdecl: |
| case tok::kw___stdcall: |
| case tok::kw___fastcall: |
| case tok::kw___w64: |
| case tok::kw___ptr64: |
| case tok::kw___forceinline: |
| return TPResult::True(); |
| |
| // The ambiguity resides in a simple-type-specifier/typename-specifier |
| // followed by a '('. The '(' could either be the start of: |
| // |
| // direct-declarator: |
| // '(' declarator ')' |
| // |
| // direct-abstract-declarator: |
| // '(' parameter-declaration-clause ')' cv-qualifier-seq[opt] |
| // exception-specification[opt] |
| // '(' abstract-declarator ')' |
| // |
| // or part of a function-style cast expression: |
| // |
| // simple-type-specifier '(' expression-list[opt] ')' |
| // |
| |
| // simple-type-specifier: |
| |
| case tok::kw_char: |
| case tok::kw_wchar_t: |
| case tok::kw_bool: |
| case tok::kw_short: |
| case tok::kw_int: |
| case tok::kw_long: |
| case tok::kw_signed: |
| case tok::kw_unsigned: |
| case tok::kw_float: |
| case tok::kw_double: |
| case tok::kw_void: |
| case tok::annot_typename: |
| if (NextToken().is(tok::l_paren)) |
| return TPResult::Ambiguous(); |
| |
| return TPResult::True(); |
| |
| // GNU typeof support. |
| case tok::kw_typeof: { |
| if (NextToken().isNot(tok::l_paren)) |
| return TPResult::True(); |
| |
| TentativeParsingAction PA(*this); |
| |
| TPResult TPR = TryParseTypeofSpecifier(); |
| bool isFollowedByParen = Tok.is(tok::l_paren); |
| |
| PA.Revert(); |
| |
| if (TPR == TPResult::Error()) |
| return TPResult::Error(); |
| |
| if (isFollowedByParen) |
| return TPResult::Ambiguous(); |
| |
| return TPResult::True(); |
| } |
| |
| default: |
| return TPResult::False(); |
| } |
| } |
| |
| /// [GNU] typeof-specifier: |
| /// 'typeof' '(' expressions ')' |
| /// 'typeof' '(' type-name ')' |
| /// |
| Parser::TPResult Parser::TryParseTypeofSpecifier() { |
| assert(Tok.is(tok::kw_typeof) && "Expected 'typeof'!"); |
| ConsumeToken(); |
| |
| assert(Tok.is(tok::l_paren) && "Expected '('"); |
| // Parse through the parens after 'typeof'. |
| ConsumeParen(); |
| if (!SkipUntil(tok::r_paren)) |
| return TPResult::Error(); |
| |
| return TPResult::Ambiguous(); |
| } |
| |
| Parser::TPResult Parser::TryParseDeclarationSpecifier() { |
| TPResult TPR = isCXXDeclarationSpecifier(); |
| if (TPR != TPResult::Ambiguous()) |
| return TPR; |
| |
| if (Tok.is(tok::kw_typeof)) |
| TryParseTypeofSpecifier(); |
| else |
| ConsumeToken(); |
| |
| assert(Tok.is(tok::l_paren) && "Expected '('!"); |
| return TPResult::Ambiguous(); |
| } |
| |
| /// isCXXFunctionDeclarator - Disambiguates between a function declarator or |
| /// a constructor-style initializer, when parsing declaration statements. |
| /// Returns true for function declarator and false for constructor-style |
| /// initializer. |
| /// If during the disambiguation process a parsing error is encountered, |
| /// the function returns true to let the declaration parsing code handle it. |
| /// |
| /// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt] |
| /// exception-specification[opt] |
| /// |
| bool Parser::isCXXFunctionDeclarator(bool warnIfAmbiguous) { |
| |
| // C++ 8.2p1: |
| // The ambiguity arising from the similarity between a function-style cast and |
| // a declaration mentioned in 6.8 can also occur in the context of a |
| // declaration. In that context, the choice is between a function declaration |
| // with a redundant set of parentheses around a parameter name and an object |
| // declaration with a function-style cast as the initializer. Just as for the |
| // ambiguities mentioned in 6.8, the resolution is to consider any construct |
| // that could possibly be a declaration a declaration. |
| |
| TentativeParsingAction PA(*this); |
| |
| ConsumeParen(); |
| TPResult TPR = TryParseParameterDeclarationClause(); |
| if (TPR == TPResult::Ambiguous() && Tok.isNot(tok::r_paren)) |
| TPR = TPResult::False(); |
| |
| SourceLocation TPLoc = Tok.getLocation(); |
| PA.Revert(); |
| |
| // In case of an error, let the declaration parsing code handle it. |
| if (TPR == TPResult::Error()) |
| return true; |
| |
| if (TPR == TPResult::Ambiguous()) { |
| // Function declarator has precedence over constructor-style initializer. |
| // Emit a warning just in case the author intended a variable definition. |
| if (warnIfAmbiguous) |
| Diag(Tok, diag::warn_parens_disambiguated_as_function_decl) |
| << SourceRange(Tok.getLocation(), TPLoc); |
| return true; |
| } |
| |
| return TPR == TPResult::True(); |
| } |
| |
| /// parameter-declaration-clause: |
| /// parameter-declaration-list[opt] '...'[opt] |
| /// parameter-declaration-list ',' '...' |
| /// |
| /// parameter-declaration-list: |
| /// parameter-declaration |
| /// parameter-declaration-list ',' parameter-declaration |
| /// |
| /// parameter-declaration: |
| /// decl-specifier-seq declarator |
| /// decl-specifier-seq declarator '=' assignment-expression |
| /// decl-specifier-seq abstract-declarator[opt] |
| /// decl-specifier-seq abstract-declarator[opt] '=' assignment-expression |
| /// |
| Parser::TPResult Parser::TryParseParameterDeclarationClause() { |
| |
| if (Tok.is(tok::r_paren)) |
| return TPResult::True(); |
| |
| // parameter-declaration-list[opt] '...'[opt] |
| // parameter-declaration-list ',' '...' |
| // |
| // parameter-declaration-list: |
| // parameter-declaration |
| // parameter-declaration-list ',' parameter-declaration |
| // |
| while (1) { |
| // '...'[opt] |
| if (Tok.is(tok::ellipsis)) { |
| ConsumeToken(); |
| return TPResult::True(); // '...' is a sign of a function declarator. |
| } |
| |
| // decl-specifier-seq |
| TPResult TPR = TryParseDeclarationSpecifier(); |
| if (TPR != TPResult::Ambiguous()) |
| return TPR; |
| |
| // declarator |
| // abstract-declarator[opt] |
| TPR = TryParseDeclarator(true/*mayBeAbstract*/); |
| if (TPR != TPResult::Ambiguous()) |
| return TPR; |
| |
| if (Tok.is(tok::equal)) { |
| // '=' assignment-expression |
| // Parse through assignment-expression. |
| tok::TokenKind StopToks[3] ={ tok::comma, tok::ellipsis, tok::r_paren }; |
| if (!SkipUntil(StopToks, 3, true/*StopAtSemi*/, true/*DontConsume*/)) |
| return TPResult::Error(); |
| } |
| |
| if (Tok.is(tok::ellipsis)) { |
| ConsumeToken(); |
| return TPResult::True(); // '...' is a sign of a function declarator. |
| } |
| |
| if (Tok.isNot(tok::comma)) |
| break; |
| ConsumeToken(); // the comma. |
| } |
| |
| return TPResult::Ambiguous(); |
| } |
| |
| /// TryParseFunctionDeclarator - We parsed a '(' and we want to try to continue |
| /// parsing as a function declarator. |
| /// If TryParseFunctionDeclarator fully parsed the function declarator, it will |
| /// return TPResult::Ambiguous(), otherwise it will return either False() or |
| /// Error(). |
| /// |
| /// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt] |
| /// exception-specification[opt] |
| /// |
| /// exception-specification: |
| /// 'throw' '(' type-id-list[opt] ')' |
| /// |
| Parser::TPResult Parser::TryParseFunctionDeclarator() { |
| |
| // The '(' is already parsed. |
| |
| TPResult TPR = TryParseParameterDeclarationClause(); |
| if (TPR == TPResult::Ambiguous() && Tok.isNot(tok::r_paren)) |
| TPR = TPResult::False(); |
| |
| if (TPR == TPResult::False() || TPR == TPResult::Error()) |
| return TPR; |
| |
| // Parse through the parens. |
| if (!SkipUntil(tok::r_paren)) |
| return TPResult::Error(); |
| |
| // cv-qualifier-seq |
| while (Tok.is(tok::kw_const) || |
| Tok.is(tok::kw_volatile) || |
| Tok.is(tok::kw_restrict) ) |
| ConsumeToken(); |
| |
| // exception-specification |
| if (Tok.is(tok::kw_throw)) { |
| ConsumeToken(); |
| if (Tok.isNot(tok::l_paren)) |
| return TPResult::Error(); |
| |
| // Parse through the parens after 'throw'. |
| ConsumeParen(); |
| if (!SkipUntil(tok::r_paren)) |
| return TPResult::Error(); |
| } |
| |
| return TPResult::Ambiguous(); |
| } |
| |
| /// '[' constant-expression[opt] ']' |
| /// |
| Parser::TPResult Parser::TryParseBracketDeclarator() { |
| ConsumeBracket(); |
| if (!SkipUntil(tok::r_square)) |
| return TPResult::Error(); |
| |
| return TPResult::Ambiguous(); |
| } |