| //===--- ParseTentative.cpp - Ambiguity Resolution Parsing ----------------===// |
| // |
| // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. |
| // See https://llvm.org/LICENSE.txt for license information. |
| // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception |
| // |
| //===----------------------------------------------------------------------===// |
| // |
| // This file implements the tentative parsing portions of the Parser |
| // interfaces, for ambiguity resolution. |
| // |
| //===----------------------------------------------------------------------===// |
| |
| #include "clang/Parse/Parser.h" |
| #include "clang/Parse/ParseDiagnostic.h" |
| #include "clang/Sema/ParsedTemplate.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: |
| // static_assert-declaration |
| case tok::kw_static_assert: |
| case tok::kw__Static_assert: |
| return true; |
| // simple-declaration |
| default: |
| return isCXXSimpleDeclaration(/*AllowForRangeDecl=*/false); |
| } |
| } |
| |
| /// 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] ';' |
| /// decl-specifier-seq ref-qualifier[opt] '[' identifier-list ']' |
| /// brace-or-equal-initializer ';' [C++17] |
| /// |
| /// (if AllowForRangeDecl specified) |
| /// for ( for-range-declaration : for-range-initializer ) statement |
| /// |
| /// for-range-declaration: |
| /// decl-specifier-seq declarator |
| /// decl-specifier-seq ref-qualifier[opt] '[' identifier-list ']' |
| /// |
| /// In any of the above cases there can be a preceding attribute-specifier-seq, |
| /// but the caller is expected to handle that. |
| bool Parser::isCXXSimpleDeclaration(bool AllowForRangeDecl) { |
| // 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. |
| |
| bool InvalidAsDeclaration = false; |
| TPResult TPR = isCXXDeclarationSpecifier(TPResult::False, |
| &InvalidAsDeclaration); |
| if (TPR != TPResult::Ambiguous) |
| return TPR != TPResult::False; // Returns true for TPResult::True or |
| // TPResult::Error. |
| |
| // FIXME: TryParseSimpleDeclaration doesn't look past the first initializer, |
| // and so gets some cases wrong. We can't carry on if we've already seen |
| // something which makes this statement invalid as a declaration in this case, |
| // since it can cause us to misparse valid code. Revisit this once |
| // TryParseInitDeclaratorList is fixed. |
| if (InvalidAsDeclaration) |
| return false; |
| |
| // 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 '(', |
| // or an identifier which doesn't resolve as anything. We need tentative |
| // parsing... |
| |
| { |
| RevertingTentativeParsingAction PA(*this); |
| TPR = TryParseSimpleDeclaration(AllowForRangeDecl); |
| } |
| |
| // 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; |
| } |
| |
| /// Try to consume a token sequence that we've already identified as |
| /// (potentially) starting a decl-specifier. |
| Parser::TPResult Parser::TryConsumeDeclarationSpecifier() { |
| switch (Tok.getKind()) { |
| case tok::kw__Atomic: |
| if (NextToken().isNot(tok::l_paren)) { |
| ConsumeToken(); |
| break; |
| } |
| LLVM_FALLTHROUGH; |
| case tok::kw_typeof: |
| case tok::kw___attribute: |
| case tok::kw___underlying_type: { |
| ConsumeToken(); |
| if (Tok.isNot(tok::l_paren)) |
| return TPResult::Error; |
| ConsumeParen(); |
| if (!SkipUntil(tok::r_paren)) |
| return TPResult::Error; |
| break; |
| } |
| |
| case tok::kw_class: |
| case tok::kw_struct: |
| case tok::kw_union: |
| case tok::kw___interface: |
| case tok::kw_enum: |
| // elaborated-type-specifier: |
| // class-key attribute-specifier-seq[opt] |
| // nested-name-specifier[opt] identifier |
| // class-key nested-name-specifier[opt] template[opt] simple-template-id |
| // enum nested-name-specifier[opt] identifier |
| // |
| // FIXME: We don't support class-specifiers nor enum-specifiers here. |
| ConsumeToken(); |
| |
| // Skip attributes. |
| if (!TrySkipAttributes()) |
| return TPResult::Error; |
| |
| if (TryAnnotateOptionalCXXScopeToken()) |
| return TPResult::Error; |
| if (Tok.is(tok::annot_cxxscope)) |
| ConsumeAnnotationToken(); |
| if (Tok.is(tok::identifier)) |
| ConsumeToken(); |
| else if (Tok.is(tok::annot_template_id)) |
| ConsumeAnnotationToken(); |
| else |
| return TPResult::Error; |
| break; |
| |
| case tok::annot_cxxscope: |
| ConsumeAnnotationToken(); |
| LLVM_FALLTHROUGH; |
| default: |
| ConsumeAnyToken(); |
| |
| if (getLangOpts().ObjC && Tok.is(tok::less)) |
| return TryParseProtocolQualifiers(); |
| break; |
| } |
| |
| return TPResult::Ambiguous; |
| } |
| |
| /// simple-declaration: |
| /// decl-specifier-seq init-declarator-list[opt] ';' |
| /// |
| /// (if AllowForRangeDecl specified) |
| /// for ( for-range-declaration : for-range-initializer ) statement |
| /// for-range-declaration: |
| /// attribute-specifier-seqopt type-specifier-seq declarator |
| /// |
| Parser::TPResult Parser::TryParseSimpleDeclaration(bool AllowForRangeDecl) { |
| if (TryConsumeDeclarationSpecifier() == TPResult::Error) |
| return TPResult::Error; |
| |
| // Two decl-specifiers in a row conclusively disambiguate this as being a |
| // simple-declaration. Don't bother calling isCXXDeclarationSpecifier in the |
| // overwhelmingly common case that the next token is a '('. |
| if (Tok.isNot(tok::l_paren)) { |
| TPResult TPR = isCXXDeclarationSpecifier(); |
| if (TPR == TPResult::Ambiguous) |
| return TPResult::True; |
| if (TPR == TPResult::True || TPR == TPResult::Error) |
| return TPR; |
| assert(TPR == TPResult::False); |
| } |
| |
| TPResult TPR = TryParseInitDeclaratorList(); |
| if (TPR != TPResult::Ambiguous) |
| return TPR; |
| |
| if (Tok.isNot(tok::semi) && (!AllowForRangeDecl || Tok.isNot(tok::colon))) |
| return TPResult::False; |
| |
| return TPResult::Ambiguous; |
| } |
| |
| /// Tentatively parse an init-declarator-list in order to disambiguate it from |
| /// an expression. |
| /// |
| /// 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: |
| /// brace-or-equal-initializer |
| /// '(' expression-list ')' |
| /// |
| /// brace-or-equal-initializer: |
| /// '=' initializer-clause |
| /// [C++11] braced-init-list |
| /// |
| /// initializer-clause: |
| /// assignment-expression |
| /// braced-init-list |
| /// |
| /// braced-init-list: |
| /// '{' initializer-list ','[opt] '}' |
| /// '{' '}' |
| /// |
| Parser::TPResult Parser::TryParseInitDeclaratorList() { |
| while (true) { |
| // declarator |
| TPResult TPR = TryParseDeclarator(false/*mayBeAbstract*/); |
| if (TPR != TPResult::Ambiguous) |
| return TPR; |
| |
| // [GNU] simple-asm-expr[opt] attributes[opt] |
| if (Tok.isOneOf(tok::kw_asm, tok::kw___attribute)) |
| return TPResult::True; |
| |
| // initializer[opt] |
| if (Tok.is(tok::l_paren)) { |
| // Parse through the parens. |
| ConsumeParen(); |
| if (!SkipUntil(tok::r_paren, StopAtSemi)) |
| return TPResult::Error; |
| } else if (Tok.is(tok::l_brace)) { |
| // A left-brace here is sufficient to disambiguate the parse; an |
| // expression can never be followed directly by a braced-init-list. |
| return TPResult::True; |
| } else if (Tok.is(tok::equal) || isTokIdentifier_in()) { |
| // MSVC and g++ won't examine the rest of declarators if '=' is |
| // encountered; they just conclude that we have a declaration. |
| // EDG parses the initializer completely, which is the proper behavior |
| // for this case. |
| // |
| // At present, Clang follows MSVC and g++, since the parser does not have |
| // the ability to parse an expression fully without recording the |
| // results of that parse. |
| // FIXME: Handle this case correctly. |
| // |
| // Also allow 'in' after an Objective-C declaration as in: |
| // for (int (^b)(void) in array). Ideally this should be done in the |
| // context of parsing for-init-statement of a foreach statement only. But, |
| // in any other context 'in' is invalid after a declaration and parser |
| // issues the error regardless of outcome of this decision. |
| // FIXME: Change if above assumption does not hold. |
| return TPResult::True; |
| } |
| |
| if (!TryConsumeToken(tok::comma)) |
| break; |
| } |
| |
| return TPResult::Ambiguous; |
| } |
| |
| struct Parser::ConditionDeclarationOrInitStatementState { |
| Parser &P; |
| bool CanBeExpression = true; |
| bool CanBeCondition = true; |
| bool CanBeInitStatement; |
| bool CanBeForRangeDecl; |
| |
| ConditionDeclarationOrInitStatementState(Parser &P, bool CanBeInitStatement, |
| bool CanBeForRangeDecl) |
| : P(P), CanBeInitStatement(CanBeInitStatement), |
| CanBeForRangeDecl(CanBeForRangeDecl) {} |
| |
| bool resolved() { |
| return CanBeExpression + CanBeCondition + CanBeInitStatement + |
| CanBeForRangeDecl < 2; |
| } |
| |
| void markNotExpression() { |
| CanBeExpression = false; |
| |
| if (!resolved()) { |
| // FIXME: Unify the parsing codepaths for condition variables and |
| // simple-declarations so that we don't need to eagerly figure out which |
| // kind we have here. (Just parse init-declarators until we reach a |
| // semicolon or right paren.) |
| RevertingTentativeParsingAction PA(P); |
| if (CanBeForRangeDecl) { |
| // Skip until we hit a ')', ';', or a ':' with no matching '?'. |
| // The final case is a for range declaration, the rest are not. |
| unsigned QuestionColonDepth = 0; |
| while (true) { |
| P.SkipUntil({tok::r_paren, tok::semi, tok::question, tok::colon}, |
| StopBeforeMatch); |
| if (P.Tok.is(tok::question)) |
| ++QuestionColonDepth; |
| else if (P.Tok.is(tok::colon)) { |
| if (QuestionColonDepth) |
| --QuestionColonDepth; |
| else { |
| CanBeCondition = CanBeInitStatement = false; |
| return; |
| } |
| } else { |
| CanBeForRangeDecl = false; |
| break; |
| } |
| P.ConsumeToken(); |
| } |
| } else { |
| // Just skip until we hit a ')' or ';'. |
| P.SkipUntil(tok::r_paren, tok::semi, StopBeforeMatch); |
| } |
| if (P.Tok.isNot(tok::r_paren)) |
| CanBeCondition = CanBeForRangeDecl = false; |
| if (P.Tok.isNot(tok::semi)) |
| CanBeInitStatement = false; |
| } |
| } |
| |
| bool markNotCondition() { |
| CanBeCondition = false; |
| return resolved(); |
| } |
| |
| bool markNotForRangeDecl() { |
| CanBeForRangeDecl = false; |
| return resolved(); |
| } |
| |
| bool update(TPResult IsDecl) { |
| switch (IsDecl) { |
| case TPResult::True: |
| markNotExpression(); |
| assert(resolved() && "can't continue after tentative parsing bails out"); |
| break; |
| case TPResult::False: |
| CanBeCondition = CanBeInitStatement = CanBeForRangeDecl = false; |
| break; |
| case TPResult::Ambiguous: |
| break; |
| case TPResult::Error: |
| CanBeExpression = CanBeCondition = CanBeInitStatement = |
| CanBeForRangeDecl = false; |
| break; |
| } |
| return resolved(); |
| } |
| |
| ConditionOrInitStatement result() const { |
| assert(CanBeExpression + CanBeCondition + CanBeInitStatement + |
| CanBeForRangeDecl < 2 && |
| "result called but not yet resolved"); |
| if (CanBeExpression) |
| return ConditionOrInitStatement::Expression; |
| if (CanBeCondition) |
| return ConditionOrInitStatement::ConditionDecl; |
| if (CanBeInitStatement) |
| return ConditionOrInitStatement::InitStmtDecl; |
| if (CanBeForRangeDecl) |
| return ConditionOrInitStatement::ForRangeDecl; |
| return ConditionOrInitStatement::Error; |
| } |
| }; |
| |
| bool Parser::isEnumBase(bool AllowSemi) { |
| assert(Tok.is(tok::colon) && "should be looking at the ':'"); |
| |
| RevertingTentativeParsingAction PA(*this); |
| // ':' |
| ConsumeToken(); |
| |
| // type-specifier-seq |
| bool InvalidAsDeclSpec = false; |
| // FIXME: We could disallow non-type decl-specifiers here, but it makes no |
| // difference: those specifiers are ill-formed regardless of the |
| // interpretation. |
| TPResult R = isCXXDeclarationSpecifier(/*BracedCastResult*/ TPResult::True, |
| &InvalidAsDeclSpec); |
| if (R == TPResult::Ambiguous) { |
| // We either have a decl-specifier followed by '(' or an undeclared |
| // identifier. |
| if (TryConsumeDeclarationSpecifier() == TPResult::Error) |
| return true; |
| |
| // If we get to the end of the enum-base, we hit either a '{' or a ';'. |
| // Don't bother checking the enumerator-list. |
| if (Tok.is(tok::l_brace) || (AllowSemi && Tok.is(tok::semi))) |
| return true; |
| |
| // A second decl-specifier unambiguously indicatges an enum-base. |
| R = isCXXDeclarationSpecifier(TPResult::True, &InvalidAsDeclSpec); |
| } |
| |
| return R != TPResult::False; |
| } |
| |
| /// Disambiguates between a declaration in a condition, a |
| /// simple-declaration in an init-statement, and an expression for |
| /// a condition of a if/switch statement. |
| /// |
| /// condition: |
| /// expression |
| /// type-specifier-seq declarator '=' assignment-expression |
| /// [C++11] type-specifier-seq declarator '=' initializer-clause |
| /// [C++11] type-specifier-seq declarator braced-init-list |
| /// [GNU] type-specifier-seq declarator simple-asm-expr[opt] attributes[opt] |
| /// '=' assignment-expression |
| /// simple-declaration: |
| /// decl-specifier-seq init-declarator-list[opt] ';' |
| /// |
| /// Note that, unlike isCXXSimpleDeclaration, we must disambiguate all the way |
| /// to the ';' to disambiguate cases like 'int(x))' (an expression) from |
| /// 'int(x);' (a simple-declaration in an init-statement). |
| Parser::ConditionOrInitStatement |
| Parser::isCXXConditionDeclarationOrInitStatement(bool CanBeInitStatement, |
| bool CanBeForRangeDecl) { |
| ConditionDeclarationOrInitStatementState State(*this, CanBeInitStatement, |
| CanBeForRangeDecl); |
| |
| if (CanBeInitStatement && Tok.is(tok::kw_using)) |
| return ConditionOrInitStatement::InitStmtDecl; |
| if (State.update(isCXXDeclarationSpecifier())) |
| return State.result(); |
| |
| // It might be a declaration; we need tentative parsing. |
| RevertingTentativeParsingAction PA(*this); |
| |
| // FIXME: A tag definition unambiguously tells us this is an init-statement. |
| if (State.update(TryConsumeDeclarationSpecifier())) |
| return State.result(); |
| assert(Tok.is(tok::l_paren) && "Expected '('"); |
| |
| while (true) { |
| // Consume a declarator. |
| if (State.update(TryParseDeclarator(false/*mayBeAbstract*/))) |
| return State.result(); |
| |
| // Attributes, asm label, or an initializer imply this is not an expression. |
| // FIXME: Disambiguate properly after an = instead of assuming that it's a |
| // valid declaration. |
| if (Tok.isOneOf(tok::equal, tok::kw_asm, tok::kw___attribute) || |
| (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace))) { |
| State.markNotExpression(); |
| return State.result(); |
| } |
| |
| // A colon here identifies a for-range declaration. |
| if (State.CanBeForRangeDecl && Tok.is(tok::colon)) |
| return ConditionOrInitStatement::ForRangeDecl; |
| |
| // At this point, it can't be a condition any more, because a condition |
| // must have a brace-or-equal-initializer. |
| if (State.markNotCondition()) |
| return State.result(); |
| |
| // Likewise, it can't be a for-range declaration any more. |
| if (State.markNotForRangeDecl()) |
| return State.result(); |
| |
| // A parenthesized initializer could be part of an expression or a |
| // simple-declaration. |
| if (Tok.is(tok::l_paren)) { |
| ConsumeParen(); |
| SkipUntil(tok::r_paren, StopAtSemi); |
| } |
| |
| if (!TryConsumeToken(tok::comma)) |
| break; |
| } |
| |
| // We reached the end. If it can now be some kind of decl, then it is. |
| if (State.CanBeCondition && Tok.is(tok::r_paren)) |
| return ConditionOrInitStatement::ConditionDecl; |
| else if (State.CanBeInitStatement && Tok.is(tok::semi)) |
| return ConditionOrInitStatement::InitStmtDecl; |
| else |
| return ConditionOrInitStatement::Expression; |
| } |
| |
| /// 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 ','; or, in C++0x, an ellipsis immediately |
| /// preceding such. 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... |
| |
| RevertingTentativeParsingAction PA(*this); |
| |
| // type-specifier-seq |
| TryConsumeDeclarationSpecifier(); |
| 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 |
| // ','; or, in C++0x, an ellipsis immediately preceding such, this |
| // is a type-id. Otherwise, it's an expression. |
| } else if (Context == TypeIdAsTemplateArgument && |
| (Tok.isOneOf(tok::greater, tok::comma) || |
| (getLangOpts().CPlusPlus11 && |
| (Tok.isOneOf(tok::greatergreater, |
| tok::greatergreatergreater) || |
| (Tok.is(tok::ellipsis) && |
| NextToken().isOneOf(tok::greater, tok::greatergreater, |
| tok::greatergreatergreater, |
| tok::comma)))))) { |
| TPR = TPResult::True; |
| isAmbiguous = true; |
| |
| } else |
| TPR = TPResult::False; |
| } |
| |
| assert(TPR == TPResult::True || TPR == TPResult::False); |
| return TPR == TPResult::True; |
| } |
| |
| /// Returns true if this is a C++11 attribute-specifier. Per |
| /// C++11 [dcl.attr.grammar]p6, two consecutive left square bracket tokens |
| /// always introduce an attribute. In Objective-C++11, this rule does not |
| /// apply if either '[' begins a message-send. |
| /// |
| /// If Disambiguate is true, we try harder to determine whether a '[[' starts |
| /// an attribute-specifier, and return CAK_InvalidAttributeSpecifier if not. |
| /// |
| /// If OuterMightBeMessageSend is true, we assume the outer '[' is either an |
| /// Obj-C message send or the start of an attribute. Otherwise, we assume it |
| /// is not an Obj-C message send. |
| /// |
| /// C++11 [dcl.attr.grammar]: |
| /// |
| /// attribute-specifier: |
| /// '[' '[' attribute-list ']' ']' |
| /// alignment-specifier |
| /// |
| /// attribute-list: |
| /// attribute[opt] |
| /// attribute-list ',' attribute[opt] |
| /// attribute '...' |
| /// attribute-list ',' attribute '...' |
| /// |
| /// attribute: |
| /// attribute-token attribute-argument-clause[opt] |
| /// |
| /// attribute-token: |
| /// identifier |
| /// identifier '::' identifier |
| /// |
| /// attribute-argument-clause: |
| /// '(' balanced-token-seq ')' |
| Parser::CXX11AttributeKind |
| Parser::isCXX11AttributeSpecifier(bool Disambiguate, |
| bool OuterMightBeMessageSend) { |
| if (Tok.is(tok::kw_alignas)) |
| return CAK_AttributeSpecifier; |
| |
| if (Tok.isNot(tok::l_square) || NextToken().isNot(tok::l_square)) |
| return CAK_NotAttributeSpecifier; |
| |
| // No tentative parsing if we don't need to look for ']]' or a lambda. |
| if (!Disambiguate && !getLangOpts().ObjC) |
| return CAK_AttributeSpecifier; |
| |
| // '[[using ns: ...]]' is an attribute. |
| if (GetLookAheadToken(2).is(tok::kw_using)) |
| return CAK_AttributeSpecifier; |
| |
| RevertingTentativeParsingAction PA(*this); |
| |
| // Opening brackets were checked for above. |
| ConsumeBracket(); |
| |
| if (!getLangOpts().ObjC) { |
| ConsumeBracket(); |
| |
| bool IsAttribute = SkipUntil(tok::r_square); |
| IsAttribute &= Tok.is(tok::r_square); |
| |
| return IsAttribute ? CAK_AttributeSpecifier : CAK_InvalidAttributeSpecifier; |
| } |
| |
| // In Obj-C++11, we need to distinguish four situations: |
| // 1a) int x[[attr]]; C++11 attribute. |
| // 1b) [[attr]]; C++11 statement attribute. |
| // 2) int x[[obj](){ return 1; }()]; Lambda in array size/index. |
| // 3a) int x[[obj get]]; Message send in array size/index. |
| // 3b) [[Class alloc] init]; Message send in message send. |
| // 4) [[obj]{ return self; }() doStuff]; Lambda in message send. |
| // (1) is an attribute, (2) is ill-formed, and (3) and (4) are accepted. |
| |
| // Check to see if this is a lambda-expression. |
| // FIXME: If this disambiguation is too slow, fold the tentative lambda parse |
| // into the tentative attribute parse below. |
| { |
| RevertingTentativeParsingAction LambdaTPA(*this); |
| LambdaIntroducer Intro; |
| LambdaIntroducerTentativeParse Tentative; |
| if (ParseLambdaIntroducer(Intro, &Tentative)) { |
| // We hit a hard error after deciding this was not an attribute. |
| // FIXME: Don't parse and annotate expressions when disambiguating |
| // against an attribute. |
| return CAK_NotAttributeSpecifier; |
| } |
| |
| switch (Tentative) { |
| case LambdaIntroducerTentativeParse::MessageSend: |
| // Case 3: The inner construct is definitely a message send, so the |
| // outer construct is definitely not an attribute. |
| return CAK_NotAttributeSpecifier; |
| |
| case LambdaIntroducerTentativeParse::Success: |
| case LambdaIntroducerTentativeParse::Incomplete: |
| // This is a lambda-introducer or attribute-specifier. |
| if (Tok.is(tok::r_square)) |
| // Case 1: C++11 attribute. |
| return CAK_AttributeSpecifier; |
| |
| if (OuterMightBeMessageSend) |
| // Case 4: Lambda in message send. |
| return CAK_NotAttributeSpecifier; |
| |
| // Case 2: Lambda in array size / index. |
| return CAK_InvalidAttributeSpecifier; |
| |
| case LambdaIntroducerTentativeParse::Invalid: |
| // No idea what this is; we couldn't parse it as a lambda-introducer. |
| // Might still be an attribute-specifier or a message send. |
| break; |
| } |
| } |
| |
| ConsumeBracket(); |
| |
| // If we don't have a lambda-introducer, then we have an attribute or a |
| // message-send. |
| bool IsAttribute = true; |
| while (Tok.isNot(tok::r_square)) { |
| if (Tok.is(tok::comma)) { |
| // Case 1: Stray commas can only occur in attributes. |
| return CAK_AttributeSpecifier; |
| } |
| |
| // Parse the attribute-token, if present. |
| // C++11 [dcl.attr.grammar]: |
| // If a keyword or an alternative token that satisfies the syntactic |
| // requirements of an identifier is contained in an attribute-token, |
| // it is considered an identifier. |
| SourceLocation Loc; |
| if (!TryParseCXX11AttributeIdentifier(Loc)) { |
| IsAttribute = false; |
| break; |
| } |
| if (Tok.is(tok::coloncolon)) { |
| ConsumeToken(); |
| if (!TryParseCXX11AttributeIdentifier(Loc)) { |
| IsAttribute = false; |
| break; |
| } |
| } |
| |
| // Parse the attribute-argument-clause, if present. |
| if (Tok.is(tok::l_paren)) { |
| ConsumeParen(); |
| if (!SkipUntil(tok::r_paren)) { |
| IsAttribute = false; |
| break; |
| } |
| } |
| |
| TryConsumeToken(tok::ellipsis); |
| |
| if (!TryConsumeToken(tok::comma)) |
| break; |
| } |
| |
| // An attribute must end ']]'. |
| if (IsAttribute) { |
| if (Tok.is(tok::r_square)) { |
| ConsumeBracket(); |
| IsAttribute = Tok.is(tok::r_square); |
| } else { |
| IsAttribute = false; |
| } |
| } |
| |
| if (IsAttribute) |
| // Case 1: C++11 statement attribute. |
| return CAK_AttributeSpecifier; |
| |
| // Case 3: Message send. |
| return CAK_NotAttributeSpecifier; |
| } |
| |
| bool Parser::TrySkipAttributes() { |
| while (Tok.isOneOf(tok::l_square, tok::kw___attribute, tok::kw___declspec, |
| tok::kw_alignas)) { |
| if (Tok.is(tok::l_square)) { |
| ConsumeBracket(); |
| if (Tok.isNot(tok::l_square)) |
| return false; |
| ConsumeBracket(); |
| if (!SkipUntil(tok::r_square) || Tok.isNot(tok::r_square)) |
| return false; |
| // Note that explicitly checking for `[[` and `]]` allows to fail as |
| // expected in the case of the Objective-C message send syntax. |
| ConsumeBracket(); |
| } else { |
| ConsumeToken(); |
| if (Tok.isNot(tok::l_paren)) |
| return false; |
| ConsumeParen(); |
| if (!SkipUntil(tok::r_paren)) |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| Parser::TPResult Parser::TryParsePtrOperatorSeq() { |
| while (true) { |
| if (TryAnnotateOptionalCXXScopeToken(true)) |
| return TPResult::Error; |
| |
| if (Tok.isOneOf(tok::star, tok::amp, tok::caret, tok::ampamp) || |
| (Tok.is(tok::annot_cxxscope) && NextToken().is(tok::star))) { |
| // ptr-operator |
| ConsumeAnyToken(); |
| |
| // Skip attributes. |
| if (!TrySkipAttributes()) |
| return TPResult::Error; |
| |
| while (Tok.isOneOf(tok::kw_const, tok::kw_volatile, tok::kw_restrict, |
| tok::kw__Nonnull, tok::kw__Nullable, |
| tok::kw__Nullable_result, tok::kw__Null_unspecified, |
| tok::kw__Atomic)) |
| ConsumeToken(); |
| } else { |
| return TPResult::True; |
| } |
| } |
| } |
| |
| /// operator-function-id: |
| /// 'operator' operator |
| /// |
| /// operator: one of |
| /// new delete new[] delete[] + - * / % ^ [...] |
| /// |
| /// conversion-function-id: |
| /// 'operator' conversion-type-id |
| /// |
| /// conversion-type-id: |
| /// type-specifier-seq conversion-declarator[opt] |
| /// |
| /// conversion-declarator: |
| /// ptr-operator conversion-declarator[opt] |
| /// |
| /// literal-operator-id: |
| /// 'operator' string-literal identifier |
| /// 'operator' user-defined-string-literal |
| Parser::TPResult Parser::TryParseOperatorId() { |
| assert(Tok.is(tok::kw_operator)); |
| ConsumeToken(); |
| |
| // Maybe this is an operator-function-id. |
| switch (Tok.getKind()) { |
| case tok::kw_new: case tok::kw_delete: |
| ConsumeToken(); |
| if (Tok.is(tok::l_square) && NextToken().is(tok::r_square)) { |
| ConsumeBracket(); |
| ConsumeBracket(); |
| } |
| return TPResult::True; |
| |
| #define OVERLOADED_OPERATOR(Name, Spelling, Token, Unary, Binary, MemOnly) \ |
| case tok::Token: |
| #define OVERLOADED_OPERATOR_MULTI(Name, Spelling, Unary, Binary, MemOnly) |
| #include "clang/Basic/OperatorKinds.def" |
| ConsumeToken(); |
| return TPResult::True; |
| |
| case tok::l_square: |
| if (NextToken().is(tok::r_square)) { |
| ConsumeBracket(); |
| ConsumeBracket(); |
| return TPResult::True; |
| } |
| break; |
| |
| case tok::l_paren: |
| if (NextToken().is(tok::r_paren)) { |
| ConsumeParen(); |
| ConsumeParen(); |
| return TPResult::True; |
| } |
| break; |
| |
| default: |
| break; |
| } |
| |
| // Maybe this is a literal-operator-id. |
| if (getLangOpts().CPlusPlus11 && isTokenStringLiteral()) { |
| bool FoundUDSuffix = false; |
| do { |
| FoundUDSuffix |= Tok.hasUDSuffix(); |
| ConsumeStringToken(); |
| } while (isTokenStringLiteral()); |
| |
| if (!FoundUDSuffix) { |
| if (Tok.is(tok::identifier)) |
| ConsumeToken(); |
| else |
| return TPResult::Error; |
| } |
| return TPResult::True; |
| } |
| |
| // Maybe this is a conversion-function-id. |
| bool AnyDeclSpecifiers = false; |
| while (true) { |
| TPResult TPR = isCXXDeclarationSpecifier(); |
| if (TPR == TPResult::Error) |
| return TPR; |
| if (TPR == TPResult::False) { |
| if (!AnyDeclSpecifiers) |
| return TPResult::Error; |
| break; |
| } |
| if (TryConsumeDeclarationSpecifier() == TPResult::Error) |
| return TPResult::Error; |
| AnyDeclSpecifiers = true; |
| } |
| return TryParsePtrOperatorSeq(); |
| } |
| |
| /// 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 ')' |
| /// [C++0x] ... |
| /// |
| /// 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: |
| /// '...'[opt] id-expression |
| /// |
| /// id-expression: |
| /// unqualified-id |
| /// qualified-id [TODO] |
| /// |
| /// unqualified-id: |
| /// identifier |
| /// operator-function-id |
| /// conversion-function-id |
| /// literal-operator-id |
| /// '~' class-name [TODO] |
| /// '~' decltype-specifier [TODO] |
| /// template-id [TODO] |
| /// |
| Parser::TPResult Parser::TryParseDeclarator(bool mayBeAbstract, |
| bool mayHaveIdentifier, |
| bool mayHaveDirectInit) { |
| // declarator: |
| // direct-declarator |
| // ptr-operator declarator |
| if (TryParsePtrOperatorSeq() == TPResult::Error) |
| return TPResult::Error; |
| |
| // direct-declarator: |
| // direct-abstract-declarator: |
| if (Tok.is(tok::ellipsis)) |
| ConsumeToken(); |
| |
| if ((Tok.isOneOf(tok::identifier, tok::kw_operator) || |
| (Tok.is(tok::annot_cxxscope) && (NextToken().is(tok::identifier) || |
| NextToken().is(tok::kw_operator)))) && |
| mayHaveIdentifier) { |
| // declarator-id |
| if (Tok.is(tok::annot_cxxscope)) { |
| CXXScopeSpec SS; |
| Actions.RestoreNestedNameSpecifierAnnotation( |
| Tok.getAnnotationValue(), Tok.getAnnotationRange(), SS); |
| if (SS.isInvalid()) |
| return TPResult::Error; |
| ConsumeAnnotationToken(); |
| } else if (Tok.is(tok::identifier)) { |
| TentativelyDeclaredIdentifiers.push_back(Tok.getIdentifierInfo()); |
| } |
| if (Tok.is(tok::kw_operator)) { |
| if (TryParseOperatorId() == TPResult::Error) |
| return TPResult::Error; |
| } else |
| ConsumeToken(); |
| } else if (Tok.is(tok::l_paren)) { |
| ConsumeParen(); |
| if (mayBeAbstract && |
| (Tok.is(tok::r_paren) || // 'int()' is a function. |
| // 'int(...)' is a function. |
| (Tok.is(tok::ellipsis) && NextToken().is(tok::r_paren)) || |
| 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.isOneOf(tok::kw___attribute, tok::kw___declspec, tok::kw___cdecl, |
| tok::kw___stdcall, tok::kw___fastcall, tok::kw___thiscall, |
| tok::kw___regcall, tok::kw___vectorcall)) |
| 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; |
| } |
| |
| if (mayHaveDirectInit) |
| return TPResult::Ambiguous; |
| |
| while (true) { |
| 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()) |
| 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 if (Tok.is(tok::kw_requires)) { |
| // declarator requires-clause |
| // A requires clause indicates a function declaration. |
| TPR = TPResult::True; |
| } else { |
| break; |
| } |
| |
| if (TPR != TPResult::Ambiguous) |
| return TPR; |
| } |
| |
| return TPResult::Ambiguous; |
| } |
| |
| bool Parser::isTentativelyDeclared(IdentifierInfo *II) { |
| return llvm::is_contained(TentativelyDeclaredIdentifiers, II); |
| } |
| |
| namespace { |
| class TentativeParseCCC final : public CorrectionCandidateCallback { |
| public: |
| TentativeParseCCC(const Token &Next) { |
| WantRemainingKeywords = false; |
| WantTypeSpecifiers = |
| Next.isOneOf(tok::l_paren, tok::r_paren, tok::greater, tok::l_brace, |
| tok::identifier, tok::comma); |
| } |
| |
| bool ValidateCandidate(const TypoCorrection &Candidate) override { |
| // Reject any candidate that only resolves to instance members since they |
| // aren't viable as standalone identifiers instead of member references. |
| if (Candidate.isResolved() && !Candidate.isKeyword() && |
| llvm::all_of(Candidate, |
| [](NamedDecl *ND) { return ND->isCXXInstanceMember(); })) |
| return false; |
| |
| return CorrectionCandidateCallback::ValidateCandidate(Candidate); |
| } |
| |
| std::unique_ptr<CorrectionCandidateCallback> clone() override { |
| return std::make_unique<TentativeParseCCC>(*this); |
| } |
| }; |
| } |
| /// 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. |
| /// |
| /// If InvalidAsDeclSpec is not null, some cases that would be ill-formed as |
| /// declaration specifiers but possibly valid as some other kind of construct |
| /// return TPResult::Ambiguous instead of TPResult::False. When this happens, |
| /// the intent is to keep trying to disambiguate, on the basis that we might |
| /// find a better reason to treat this construct as a declaration later on. |
| /// When this happens and the name could possibly be valid in some other |
| /// syntactic context, *InvalidAsDeclSpec is set to 'true'. The current cases |
| /// that trigger this are: |
| /// |
| /// * When parsing X::Y (with no 'typename') where X is dependent |
| /// * When parsing X<Y> where X is undeclared |
| /// |
| /// decl-specifier: |
| /// storage-class-specifier |
| /// type-specifier |
| /// function-specifier |
| /// 'friend' |
| /// 'typedef' |
| /// [C++11] 'constexpr' |
| /// [C++20] 'consteval' |
| /// [GNU] attributes declaration-specifiers[opt] |
| /// |
| /// storage-class-specifier: |
| /// 'register' |
| /// 'static' |
| /// 'extern' |
| /// 'mutable' |
| /// 'auto' |
| /// [GNU] '__thread' |
| /// [C++11] 'thread_local' |
| /// [C11] '_Thread_local' |
| /// |
| /// 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++11] 'auto' |
| /// [GNU] '__auto_type' |
| /// [C++11] 'decltype' ( expression ) |
| /// [C++1y] 'decltype' ( 'auto' ) |
| /// |
| /// 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(Parser::TPResult BracedCastResult, |
| bool *InvalidAsDeclSpec) { |
| auto IsPlaceholderSpecifier = [&] (TemplateIdAnnotation *TemplateId, |
| int Lookahead) { |
| // We have a placeholder-constraint (we check for 'auto' or 'decltype' to |
| // distinguish 'C<int>;' from 'C<int> auto c = 1;') |
| return TemplateId->Kind == TNK_Concept_template && |
| GetLookAheadToken(Lookahead + 1).isOneOf(tok::kw_auto, tok::kw_decltype, |
| // If we have an identifier here, the user probably forgot the |
| // 'auto' in the placeholder constraint, e.g. 'C<int> x = 2;' |
| // This will be diagnosed nicely later, so disambiguate as a |
| // declaration. |
| tok::identifier); |
| }; |
| switch (Tok.getKind()) { |
| case tok::identifier: { |
| // Check for need to substitute AltiVec __vector keyword |
| // for "vector" identifier. |
| if (TryAltiVecVectorToken()) |
| return TPResult::True; |
| |
| const Token &Next = NextToken(); |
| // In 'foo bar', 'foo' is always a type name outside of Objective-C. |
| if (!getLangOpts().ObjC && Next.is(tok::identifier)) |
| return TPResult::True; |
| |
| if (Next.isNot(tok::coloncolon) && Next.isNot(tok::less)) { |
| // Determine whether this is a valid expression. If not, we will hit |
| // a parse error one way or another. In that case, tell the caller that |
| // this is ambiguous. Typo-correct to type and expression keywords and |
| // to types and identifiers, in order to try to recover from errors. |
| TentativeParseCCC CCC(Next); |
| switch (TryAnnotateName(&CCC)) { |
| case ANK_Error: |
| return TPResult::Error; |
| case ANK_TentativeDecl: |
| return TPResult::False; |
| case ANK_TemplateName: |
| // In C++17, this could be a type template for class template argument |
| // deduction. Try to form a type annotation for it. If we're in a |
| // template template argument, we'll undo this when checking the |
| // validity of the argument. |
| if (getLangOpts().CPlusPlus17) { |
| if (TryAnnotateTypeOrScopeToken()) |
| return TPResult::Error; |
| if (Tok.isNot(tok::identifier)) |
| break; |
| } |
| |
| // A bare type template-name which can't be a template template |
| // argument is an error, and was probably intended to be a type. |
| return GreaterThanIsOperator ? TPResult::True : TPResult::False; |
| case ANK_Unresolved: |
| return InvalidAsDeclSpec ? TPResult::Ambiguous : TPResult::False; |
| case ANK_Success: |
| break; |
| } |
| assert(Tok.isNot(tok::identifier) && |
| "TryAnnotateName succeeded without producing an annotation"); |
| } else { |
| // This might possibly be a type with a dependent scope specifier and |
| // a missing 'typename' keyword. Don't use TryAnnotateName in this case, |
| // since it will annotate as a primary expression, and we want to use the |
| // "missing 'typename'" logic. |
| if (TryAnnotateTypeOrScopeToken()) |
| return TPResult::Error; |
| // If annotation failed, assume it's a non-type. |
| // FIXME: If this happens due to an undeclared identifier, treat it as |
| // ambiguous. |
| if (Tok.is(tok::identifier)) |
| return TPResult::False; |
| } |
| |
| // We annotated this token as something. Recurse to handle whatever we got. |
| return isCXXDeclarationSpecifier(BracedCastResult, InvalidAsDeclSpec); |
| } |
| |
| 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 TPResult::Error; |
| return isCXXDeclarationSpecifier(BracedCastResult, InvalidAsDeclSpec); |
| |
| case tok::coloncolon: { // ::foo::bar |
| const Token &Next = NextToken(); |
| if (Next.isOneOf(tok::kw_new, // ::new |
| tok::kw_delete)) // ::delete |
| return TPResult::False; |
| LLVM_FALLTHROUGH; |
| } |
| case tok::kw___super: |
| case tok::kw_decltype: |
| // Annotate typenames and C++ scope specifiers. If we get one, just |
| // recurse to handle whatever we get. |
| if (TryAnnotateTypeOrScopeToken()) |
| return TPResult::Error; |
| return isCXXDeclarationSpecifier(BracedCastResult, InvalidAsDeclSpec); |
| |
| // decl-specifier: |
| // storage-class-specifier |
| // type-specifier |
| // function-specifier |
| // 'friend' |
| // 'typedef' |
| // 'constexpr' |
| case tok::kw_friend: |
| case tok::kw_typedef: |
| case tok::kw_constexpr: |
| case tok::kw_consteval: |
| case tok::kw_constinit: |
| // 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: |
| case tok::kw_thread_local: |
| case tok::kw__Thread_local: |
| // function-specifier |
| case tok::kw_inline: |
| case tok::kw_virtual: |
| case tok::kw_explicit: |
| |
| // Modules |
| case tok::kw___module_private__: |
| |
| // Debugger support |
| case tok::kw___unknown_anytype: |
| |
| // 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: |
| case tok::kw___interface: |
| // enum-specifier |
| case tok::kw_enum: |
| // cv-qualifier |
| case tok::kw_const: |
| case tok::kw_volatile: |
| return TPResult::True; |
| |
| // OpenCL address space qualifiers |
| case tok::kw_private: |
| if (!getLangOpts().OpenCL) |
| return TPResult::False; |
| LLVM_FALLTHROUGH; |
| case tok::kw___private: |
| case tok::kw___local: |
| case tok::kw___global: |
| case tok::kw___constant: |
| case tok::kw___generic: |
| // OpenCL access qualifiers |
| case tok::kw___read_only: |
| case tok::kw___write_only: |
| case tok::kw___read_write: |
| // OpenCL pipe |
| case tok::kw_pipe: |
| |
| // GNU |
| case tok::kw_restrict: |
| case tok::kw__Complex: |
| case tok::kw___attribute: |
| case tok::kw___auto_type: |
| return TPResult::True; |
| |
| // Microsoft |
| case tok::kw___declspec: |
| case tok::kw___cdecl: |
| case tok::kw___stdcall: |
| case tok::kw___fastcall: |
| case tok::kw___thiscall: |
| case tok::kw___regcall: |
| case tok::kw___vectorcall: |
| case tok::kw___w64: |
| case tok::kw___sptr: |
| case tok::kw___uptr: |
| case tok::kw___ptr64: |
| case tok::kw___ptr32: |
| case tok::kw___forceinline: |
| case tok::kw___unaligned: |
| case tok::kw__Nonnull: |
| case tok::kw__Nullable: |
| case tok::kw__Nullable_result: |
| case tok::kw__Null_unspecified: |
| case tok::kw___kindof: |
| return TPResult::True; |
| |
| // Borland |
| case tok::kw___pascal: |
| return TPResult::True; |
| |
| // AltiVec |
| case tok::kw___vector: |
| return TPResult::True; |
| |
| case tok::annot_template_id: { |
| TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok); |
| // If lookup for the template-name found nothing, don't assume we have a |
| // definitive disambiguation result yet. |
| if ((TemplateId->hasInvalidName() || |
| TemplateId->Kind == TNK_Undeclared_template) && |
| InvalidAsDeclSpec) { |
| // 'template-id(' can be a valid expression but not a valid decl spec if |
| // the template-name is not declared, but we don't consider this to be a |
| // definitive disambiguation. In any other context, it's an error either |
| // way. |
| *InvalidAsDeclSpec = NextToken().is(tok::l_paren); |
| return TPResult::Ambiguous; |
| } |
| if (TemplateId->hasInvalidName()) |
| return TPResult::Error; |
| if (IsPlaceholderSpecifier(TemplateId, /*Lookahead=*/0)) |
| return TPResult::True; |
| if (TemplateId->Kind != TNK_Type_template) |
| return TPResult::False; |
| CXXScopeSpec SS; |
| AnnotateTemplateIdTokenAsType(SS); |
| assert(Tok.is(tok::annot_typename)); |
| goto case_typename; |
| } |
| |
| case tok::annot_cxxscope: // foo::bar or ::foo::bar, but already parsed |
| // We've already annotated a scope; try to annotate a type. |
| if (TryAnnotateTypeOrScopeToken()) |
| return TPResult::Error; |
| if (!Tok.is(tok::annot_typename)) { |
| if (Tok.is(tok::annot_cxxscope) && |
| NextToken().is(tok::annot_template_id)) { |
| TemplateIdAnnotation *TemplateId = |
| takeTemplateIdAnnotation(NextToken()); |
| if (TemplateId->hasInvalidName()) { |
| if (InvalidAsDeclSpec) { |
| *InvalidAsDeclSpec = NextToken().is(tok::l_paren); |
| return TPResult::Ambiguous; |
| } |
| return TPResult::Error; |
| } |
| if (IsPlaceholderSpecifier(TemplateId, /*Lookahead=*/1)) |
| return TPResult::True; |
| } |
| // If the next token is an identifier or a type qualifier, then this |
| // can't possibly be a valid expression either. |
| if (Tok.is(tok::annot_cxxscope) && NextToken().is(tok::identifier)) { |
| CXXScopeSpec SS; |
| Actions.RestoreNestedNameSpecifierAnnotation(Tok.getAnnotationValue(), |
| Tok.getAnnotationRange(), |
| SS); |
| if (SS.getScopeRep() && SS.getScopeRep()->isDependent()) { |
| RevertingTentativeParsingAction PA(*this); |
| ConsumeAnnotationToken(); |
| ConsumeToken(); |
| bool isIdentifier = Tok.is(tok::identifier); |
| TPResult TPR = TPResult::False; |
| if (!isIdentifier) |
| TPR = isCXXDeclarationSpecifier(BracedCastResult, |
| InvalidAsDeclSpec); |
| |
| if (isIdentifier || |
| TPR == TPResult::True || TPR == TPResult::Error) |
| return TPResult::Error; |
| |
| if (InvalidAsDeclSpec) { |
| // We can't tell whether this is a missing 'typename' or a valid |
| // expression. |
| *InvalidAsDeclSpec = true; |
| return TPResult::Ambiguous; |
| } else { |
| // In MS mode, if InvalidAsDeclSpec is not provided, and the tokens |
| // are or the form *) or &) *> or &> &&>, this can't be an expression. |
| // The typename must be missing. |
| if (getLangOpts().MSVCCompat) { |
| if (((Tok.is(tok::amp) || Tok.is(tok::star)) && |
| (NextToken().is(tok::r_paren) || |
| NextToken().is(tok::greater))) || |
| (Tok.is(tok::ampamp) && NextToken().is(tok::greater))) |
| return TPResult::True; |
| } |
| } |
| } else { |
| // Try to resolve the name. If it doesn't exist, assume it was |
| // intended to name a type and keep disambiguating. |
| switch (TryAnnotateName()) { |
| case ANK_Error: |
| return TPResult::Error; |
| case ANK_TentativeDecl: |
| return TPResult::False; |
| case ANK_TemplateName: |
| // In C++17, this could be a type template for class template |
| // argument deduction. |
| if (getLangOpts().CPlusPlus17) { |
| if (TryAnnotateTypeOrScopeToken()) |
| return TPResult::Error; |
| if (Tok.isNot(tok::identifier)) |
| break; |
| } |
| |
| // A bare type template-name which can't be a template template |
| // argument is an error, and was probably intended to be a type. |
| // In C++17, this could be class template argument deduction. |
| return (getLangOpts().CPlusPlus17 || GreaterThanIsOperator) |
| ? TPResult::True |
| : TPResult::False; |
| case ANK_Unresolved: |
| return InvalidAsDeclSpec ? TPResult::Ambiguous : TPResult::False; |
| case ANK_Success: |
| break; |
| } |
| |
| // Annotated it, check again. |
| assert(Tok.isNot(tok::annot_cxxscope) || |
| NextToken().isNot(tok::identifier)); |
| return isCXXDeclarationSpecifier(BracedCastResult, InvalidAsDeclSpec); |
| } |
| } |
| return TPResult::False; |
| } |
| // If that succeeded, fallthrough into the generic simple-type-id case. |
| LLVM_FALLTHROUGH; |
| |
| // 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::annot_typename: |
| case_typename: |
| // In Objective-C, we might have a protocol-qualified type. |
| if (getLangOpts().ObjC && NextToken().is(tok::less)) { |
| // Tentatively parse the protocol qualifiers. |
| RevertingTentativeParsingAction PA(*this); |
| ConsumeAnyToken(); // The type token |
| |
| TPResult TPR = TryParseProtocolQualifiers(); |
| bool isFollowedByParen = Tok.is(tok::l_paren); |
| bool isFollowedByBrace = Tok.is(tok::l_brace); |
| |
| if (TPR == TPResult::Error) |
| return TPResult::Error; |
| |
| if (isFollowedByParen) |
| return TPResult::Ambiguous; |
| |
| if (getLangOpts().CPlusPlus11 && isFollowedByBrace) |
| return BracedCastResult; |
| |
| return TPResult::True; |
| } |
| LLVM_FALLTHROUGH; |
| |
| case tok::kw_char: |
| case tok::kw_wchar_t: |
| case tok::kw_char8_t: |
| case tok::kw_char16_t: |
| case tok::kw_char32_t: |
| case tok::kw_bool: |
| case tok::kw_short: |
| case tok::kw_int: |
| case tok::kw_long: |
| case tok::kw___int64: |
| case tok::kw___int128: |
| case tok::kw_signed: |
| case tok::kw_unsigned: |
| case tok::kw_half: |
| case tok::kw_float: |
| case tok::kw_double: |
| case tok::kw___bf16: |
| case tok::kw__Float16: |
| case tok::kw___float128: |
| case tok::kw___ibm128: |
| case tok::kw_void: |
| case tok::annot_decltype: |
| #define GENERIC_IMAGE_TYPE(ImgType, Id) case tok::kw_##ImgType##_t: |
| #include "clang/Basic/OpenCLImageTypes.def" |
| if (NextToken().is(tok::l_paren)) |
| return TPResult::Ambiguous; |
| |
| // This is a function-style cast in all cases we disambiguate other than |
| // one: |
| // struct S { |
| // enum E : int { a = 4 }; // enum |
| // enum E : int { 4 }; // bit-field |
| // }; |
| if (getLangOpts().CPlusPlus11 && NextToken().is(tok::l_brace)) |
| return BracedCastResult; |
| |
| if (isStartOfObjCClassMessageMissingOpenBracket()) |
| return TPResult::False; |
| |
| return TPResult::True; |
| |
| // GNU typeof support. |
| case tok::kw_typeof: { |
| if (NextToken().isNot(tok::l_paren)) |
| return TPResult::True; |
| |
| RevertingTentativeParsingAction PA(*this); |
| |
| TPResult TPR = TryParseTypeofSpecifier(); |
| bool isFollowedByParen = Tok.is(tok::l_paren); |
| bool isFollowedByBrace = Tok.is(tok::l_brace); |
| |
| if (TPR == TPResult::Error) |
| return TPResult::Error; |
| |
| if (isFollowedByParen) |
| return TPResult::Ambiguous; |
| |
| if (getLangOpts().CPlusPlus11 && isFollowedByBrace) |
| return BracedCastResult; |
| |
| return TPResult::True; |
| } |
| |
| // C++0x type traits support |
| case tok::kw___underlying_type: |
| return TPResult::True; |
| |
| // C11 _Atomic |
| case tok::kw__Atomic: |
| return TPResult::True; |
| |
| case tok::kw__BitInt: |
| case tok::kw__ExtInt: { |
| if (NextToken().isNot(tok::l_paren)) |
| return TPResult::Error; |
| RevertingTentativeParsingAction PA(*this); |
| ConsumeToken(); |
| ConsumeParen(); |
| |
| if (!SkipUntil(tok::r_paren, StopAtSemi)) |
| return TPResult::Error; |
| |
| if (Tok.is(tok::l_paren)) |
| return TPResult::Ambiguous; |
| |
| if (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace)) |
| return BracedCastResult; |
| |
| return TPResult::True; |
| } |
| default: |
| return TPResult::False; |
| } |
| } |
| |
| bool Parser::isCXXDeclarationSpecifierAType() { |
| switch (Tok.getKind()) { |
| // typename-specifier |
| case tok::annot_decltype: |
| case tok::annot_template_id: |
| case tok::annot_typename: |
| case tok::kw_typeof: |
| case tok::kw___underlying_type: |
| return true; |
| |
| // elaborated-type-specifier |
| case tok::kw_class: |
| case tok::kw_struct: |
| case tok::kw_union: |
| case tok::kw___interface: |
| case tok::kw_enum: |
| return true; |
| |
| // simple-type-specifier |
| case tok::kw_char: |
| case tok::kw_wchar_t: |
| case tok::kw_char8_t: |
| case tok::kw_char16_t: |
| case tok::kw_char32_t: |
| case tok::kw_bool: |
| case tok::kw_short: |
| case tok::kw_int: |
| case tok::kw__ExtInt: |
| case tok::kw__BitInt: |
| case tok::kw_long: |
| case tok::kw___int64: |
| case tok::kw___int128: |
| case tok::kw_signed: |
| case tok::kw_unsigned: |
| case tok::kw_half: |
| case tok::kw_float: |
| case tok::kw_double: |
| case tok::kw___bf16: |
| case tok::kw__Float16: |
| case tok::kw___float128: |
| case tok::kw___ibm128: |
| case tok::kw_void: |
| case tok::kw___unknown_anytype: |
| case tok::kw___auto_type: |
| #define GENERIC_IMAGE_TYPE(ImgType, Id) case tok::kw_##ImgType##_t: |
| #include "clang/Basic/OpenCLImageTypes.def" |
| return true; |
| |
| case tok::kw_auto: |
| return getLangOpts().CPlusPlus11; |
| |
| case tok::kw__Atomic: |
| // "_Atomic foo" |
| return NextToken().is(tok::l_paren); |
| |
| default: |
| return 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, StopAtSemi)) |
| return TPResult::Error; |
| |
| return TPResult::Ambiguous; |
| } |
| |
| /// [ObjC] protocol-qualifiers: |
| //// '<' identifier-list '>' |
| Parser::TPResult Parser::TryParseProtocolQualifiers() { |
| assert(Tok.is(tok::less) && "Expected '<' for qualifier list"); |
| ConsumeToken(); |
| do { |
| if (Tok.isNot(tok::identifier)) |
| return TPResult::Error; |
| ConsumeToken(); |
| |
| if (Tok.is(tok::comma)) { |
| ConsumeToken(); |
| continue; |
| } |
| |
| if (Tok.is(tok::greater)) { |
| ConsumeToken(); |
| return TPResult::Ambiguous; |
| } |
| } while (false); |
| |
| return TPResult::Error; |
| } |
| |
| /// 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 *IsAmbiguous) { |
| |
| // 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. |
| |
| RevertingTentativeParsingAction PA(*this); |
| |
| ConsumeParen(); |
| bool InvalidAsDeclaration = false; |
| TPResult TPR = TryParseParameterDeclarationClause(&InvalidAsDeclaration); |
| if (TPR == TPResult::Ambiguous) { |
| if (Tok.isNot(tok::r_paren)) |
| TPR = TPResult::False; |
| else { |
| const Token &Next = NextToken(); |
| if (Next.isOneOf(tok::amp, tok::ampamp, tok::kw_const, tok::kw_volatile, |
| tok::kw_throw, tok::kw_noexcept, tok::l_square, |
| tok::l_brace, tok::kw_try, tok::equal, tok::arrow) || |
| isCXX11VirtSpecifier(Next)) |
| // The next token cannot appear after a constructor-style initializer, |
| // and can appear next in a function definition. This must be a function |
| // declarator. |
| TPR = TPResult::True; |
| else if (InvalidAsDeclaration) |
| // Use the absence of 'typename' as a tie-breaker. |
| TPR = TPResult::False; |
| } |
| } |
| |
| if (IsAmbiguous && TPR == TPResult::Ambiguous) |
| *IsAmbiguous = true; |
| |
| // In case of an error, let the declaration parsing code handle it. |
| return TPR != TPResult::False; |
| } |
| |
| /// parameter-declaration-clause: |
| /// parameter-declaration-list[opt] '...'[opt] |
| /// parameter-declaration-list ',' '...' |
| /// |
| /// parameter-declaration-list: |
| /// parameter-declaration |
| /// parameter-declaration-list ',' parameter-declaration |
| /// |
| /// parameter-declaration: |
| /// attribute-specifier-seq[opt] decl-specifier-seq declarator attributes[opt] |
| /// attribute-specifier-seq[opt] decl-specifier-seq declarator attributes[opt] |
| /// '=' assignment-expression |
| /// attribute-specifier-seq[opt] decl-specifier-seq abstract-declarator[opt] |
| /// attributes[opt] |
| /// attribute-specifier-seq[opt] decl-specifier-seq abstract-declarator[opt] |
| /// attributes[opt] '=' assignment-expression |
| /// |
| Parser::TPResult |
| Parser::TryParseParameterDeclarationClause(bool *InvalidAsDeclaration, |
| bool VersusTemplateArgument) { |
| |
| if (Tok.is(tok::r_paren)) |
| return TPResult::Ambiguous; |
| |
| // parameter-declaration-list[opt] '...'[opt] |
| // parameter-declaration-list ',' '...' |
| // |
| // parameter-declaration-list: |
| // parameter-declaration |
| // parameter-declaration-list ',' parameter-declaration |
| // |
| while (true) { |
| // '...'[opt] |
| if (Tok.is(tok::ellipsis)) { |
| ConsumeToken(); |
| if (Tok.is(tok::r_paren)) |
| return TPResult::True; // '...)' is a sign of a function declarator. |
| else |
| return TPResult::False; |
| } |
| |
| // An attribute-specifier-seq here is a sign of a function declarator. |
| if (isCXX11AttributeSpecifier(/*Disambiguate*/false, |
| /*OuterMightBeMessageSend*/true)) |
| return TPResult::True; |
| |
| ParsedAttributes attrs(AttrFactory); |
| MaybeParseMicrosoftAttributes(attrs); |
| |
| // decl-specifier-seq |
| // A parameter-declaration's initializer must be preceded by an '=', so |
| // decl-specifier-seq '{' is not a parameter in C++11. |
| TPResult TPR = isCXXDeclarationSpecifier(TPResult::False, |
| InvalidAsDeclaration); |
| // A declaration-specifier (not followed by '(' or '{') means this can't be |
| // an expression, but it could still be a template argument. |
| if (TPR != TPResult::Ambiguous && |
| !(VersusTemplateArgument && TPR == TPResult::True)) |
| return TPR; |
| |
| bool SeenType = false; |
| do { |
| SeenType |= isCXXDeclarationSpecifierAType(); |
| if (TryConsumeDeclarationSpecifier() == TPResult::Error) |
| return TPResult::Error; |
| |
| // If we see a parameter name, this can't be a template argument. |
| if (SeenType && Tok.is(tok::identifier)) |
| return TPResult::True; |
| |
| TPR = isCXXDeclarationSpecifier(TPResult::False, |
| InvalidAsDeclaration); |
| if (TPR == TPResult::Error) |
| return TPR; |
| |
| // Two declaration-specifiers means this can't be an expression. |
| if (TPR == TPResult::True && !VersusTemplateArgument) |
| return TPR; |
| } while (TPR != TPResult::False); |
| |
| // declarator |
| // abstract-declarator[opt] |
| TPR = TryParseDeclarator(true/*mayBeAbstract*/); |
| if (TPR != TPResult::Ambiguous) |
| return TPR; |
| |
| // [GNU] attributes[opt] |
| if (Tok.is(tok::kw___attribute)) |
| return TPResult::True; |
| |
| // If we're disambiguating a template argument in a default argument in |
| // a class definition versus a parameter declaration, an '=' here |
| // disambiguates the parse one way or the other. |
| // If this is a parameter, it must have a default argument because |
| // (a) the previous parameter did, and |
| // (b) this must be the first declaration of the function, so we can't |
| // inherit any default arguments from elsewhere. |
| // FIXME: If we reach a ')' without consuming any '>'s, then this must |
| // also be a function parameter (that's missing its default argument). |
| if (VersusTemplateArgument) |
| return Tok.is(tok::equal) ? TPResult::True : TPResult::False; |
| |
| if (Tok.is(tok::equal)) { |
| // '=' assignment-expression |
| // Parse through assignment-expression. |
| if (!SkipUntil(tok::comma, tok::r_paren, StopAtSemi | StopBeforeMatch)) |
| return TPResult::Error; |
| } |
| |
| if (Tok.is(tok::ellipsis)) { |
| ConsumeToken(); |
| if (Tok.is(tok::r_paren)) |
| return TPResult::True; // '...)' is a sign of a function declarator. |
| else |
| return TPResult::False; |
| } |
| |
| if (!TryConsumeToken(tok::comma)) |
| break; |
| } |
| |
| 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, StopAtSemi)) |
| return TPResult::Error; |
| |
| // cv-qualifier-seq |
| while (Tok.isOneOf(tok::kw_const, tok::kw_volatile, tok::kw___unaligned, |
| tok::kw_restrict)) |
| ConsumeToken(); |
| |
| // ref-qualifier[opt] |
| if (Tok.isOneOf(tok::amp, tok::ampamp)) |
| 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, StopAtSemi)) |
| return TPResult::Error; |
| } |
| if (Tok.is(tok::kw_noexcept)) { |
| ConsumeToken(); |
| // Possibly an expression as well. |
| if (Tok.is(tok::l_paren)) { |
| // Find the matching rparen. |
| ConsumeParen(); |
| if (!SkipUntil(tok::r_paren, StopAtSemi)) |
| return TPResult::Error; |
| } |
| } |
| |
| return TPResult::Ambiguous; |
| } |
| |
| /// '[' constant-expression[opt] ']' |
| /// |
| Parser::TPResult Parser::TryParseBracketDeclarator() { |
| ConsumeBracket(); |
| |
| // A constant-expression cannot begin with a '{', but the |
| // expr-or-braced-init-list of a postfix-expression can. |
| if (Tok.is(tok::l_brace)) |
| return TPResult::False; |
| |
| if (!SkipUntil(tok::r_square, tok::comma, StopAtSemi | StopBeforeMatch)) |
| return TPResult::Error; |
| |
| // If we hit a comma before the ']', this is not a constant-expression, |
| // but might still be the expr-or-braced-init-list of a postfix-expression. |
| if (Tok.isNot(tok::r_square)) |
| return TPResult::False; |
| |
| ConsumeBracket(); |
| return TPResult::Ambiguous; |
| } |
| |
| /// Determine whether we might be looking at the '<' template-argument-list '>' |
| /// of a template-id or simple-template-id, rather than a less-than comparison. |
| /// This will often fail and produce an ambiguity, but should never be wrong |
| /// if it returns True or False. |
| Parser::TPResult Parser::isTemplateArgumentList(unsigned TokensToSkip) { |
| if (!TokensToSkip) { |
| if (Tok.isNot(tok::less)) |
| return TPResult::False; |
| if (NextToken().is(tok::greater)) |
| return TPResult::True; |
| } |
| |
| RevertingTentativeParsingAction PA(*this); |
| |
| while (TokensToSkip) { |
| ConsumeAnyToken(); |
| --TokensToSkip; |
| } |
| |
| if (!TryConsumeToken(tok::less)) |
| return TPResult::False; |
| |
| // We can't do much to tell an expression apart from a template-argument, |
| // but one good distinguishing factor is that a "decl-specifier" not |
| // followed by '(' or '{' can't appear in an expression. |
| bool InvalidAsTemplateArgumentList = false; |
| if (isCXXDeclarationSpecifier(TPResult::False, |
| &InvalidAsTemplateArgumentList) == |
| TPResult::True) |
| return TPResult::True; |
| if (InvalidAsTemplateArgumentList) |
| return TPResult::False; |
| |
| // FIXME: In many contexts, X<thing1, Type> can only be a |
| // template-argument-list. But that's not true in general: |
| // |
| // using b = int; |
| // void f() { |
| // int a = A<B, b, c = C>D; // OK, declares b, not a template-id. |
| // |
| // X<Y<0, int> // ', int>' might be end of X's template argument list |
| // |
| // We might be able to disambiguate a few more cases if we're careful. |
| |
| // A template-argument-list must be terminated by a '>'. |
| if (SkipUntil({tok::greater, tok::greatergreater, tok::greatergreatergreater}, |
| StopAtSemi | StopBeforeMatch)) |
| return TPResult::Ambiguous; |
| return TPResult::False; |
| } |
| |
| /// Determine whether we might be looking at the '(' of a C++20 explicit(bool) |
| /// in an earlier language mode. |
| Parser::TPResult Parser::isExplicitBool() { |
| assert(Tok.is(tok::l_paren) && "expected to be looking at a '(' token"); |
| |
| RevertingTentativeParsingAction PA(*this); |
| ConsumeParen(); |
| |
| // We can only have 'explicit' on a constructor, conversion function, or |
| // deduction guide. The declarator of a deduction guide cannot be |
| // parenthesized, so we know this isn't a deduction guide. So the only |
| // thing we need to check for is some number of parens followed by either |
| // the current class name or 'operator'. |
| while (Tok.is(tok::l_paren)) |
| ConsumeParen(); |
| |
| if (TryAnnotateOptionalCXXScopeToken()) |
| return TPResult::Error; |
| |
| // Class-scope constructor and conversion function names can't really be |
| // qualified, but we get better diagnostics if we assume they can be. |
| CXXScopeSpec SS; |
| if (Tok.is(tok::annot_cxxscope)) { |
| Actions.RestoreNestedNameSpecifierAnnotation(Tok.getAnnotationValue(), |
| Tok.getAnnotationRange(), |
| SS); |
| ConsumeAnnotationToken(); |
| } |
| |
| // 'explicit(operator' might be explicit(bool) or the declaration of a |
| // conversion function, but it's probably a conversion function. |
| if (Tok.is(tok::kw_operator)) |
| return TPResult::Ambiguous; |
| |
| // If this can't be a constructor name, it can only be explicit(bool). |
| if (Tok.isNot(tok::identifier) && Tok.isNot(tok::annot_template_id)) |
| return TPResult::True; |
| if (!Actions.isCurrentClassName(Tok.is(tok::identifier) |
| ? *Tok.getIdentifierInfo() |
| : *takeTemplateIdAnnotation(Tok)->Name, |
| getCurScope(), &SS)) |
| return TPResult::True; |
| // Formally, we must have a right-paren after the constructor name to match |
| // the grammar for a constructor. But clang permits a parenthesized |
| // constructor declarator, so also allow a constructor declarator to follow |
| // with no ')' token after the constructor name. |
| if (!NextToken().is(tok::r_paren) && |
| !isConstructorDeclarator(/*Unqualified=*/SS.isEmpty(), |
| /*DeductionGuide=*/false)) |
| return TPResult::True; |
| |
| // Might be explicit(bool) or a parenthesized constructor name. |
| return TPResult::Ambiguous; |
| } |
