1 //===--- ParseTentative.cpp - Ambiguity Resolution Parsing ----------------===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file implements the tentative parsing portions of the Parser
11 // interfaces, for ambiguity resolution.
13 //===----------------------------------------------------------------------===//
15 #include "clang/Parse/Parser.h"
16 #include "clang/Parse/ParseDiagnostic.h"
17 #include "clang/Sema/ParsedTemplate.h"
18 using namespace clang;
20 /// isCXXDeclarationStatement - C++-specialized function that disambiguates
21 /// between a declaration or an expression statement, when parsing function
22 /// bodies. Returns true for declaration, false for expression.
24 /// declaration-statement:
27 /// block-declaration:
28 /// simple-declaration
30 /// namespace-alias-definition
33 /// [C++0x] static_assert-declaration
36 /// 'asm' '(' string-literal ')' ';'
38 /// namespace-alias-definition:
39 /// 'namespace' identifier = qualified-namespace-specifier ';'
41 /// using-declaration:
42 /// 'using' typename[opt] '::'[opt] nested-name-specifier
43 /// unqualified-id ';'
44 /// 'using' '::' unqualified-id ;
47 /// 'using' 'namespace' '::'[opt] nested-name-specifier[opt]
48 /// namespace-name ';'
50 bool Parser::isCXXDeclarationStatement() {
51 switch (Tok.getKind()) {
54 // namespace-alias-definition
55 case tok::kw_namespace:
59 // static_assert-declaration
60 case tok::kw_static_assert:
61 case tok::kw__Static_assert:
65 return isCXXSimpleDeclaration(/*AllowForRangeDecl=*/false);
69 /// isCXXSimpleDeclaration - C++-specialized function that disambiguates
70 /// between a simple-declaration or an expression-statement.
71 /// If during the disambiguation process a parsing error is encountered,
72 /// the function returns true to let the declaration parsing code handle it.
73 /// Returns false if the statement is disambiguated as expression.
75 /// simple-declaration:
76 /// decl-specifier-seq init-declarator-list[opt] ';'
77 /// decl-specifier-seq ref-qualifier[opt] '[' identifier-list ']'
78 /// brace-or-equal-initializer ';' [C++17]
80 /// (if AllowForRangeDecl specified)
81 /// for ( for-range-declaration : for-range-initializer ) statement
83 /// for-range-declaration:
84 /// decl-specifier-seq declarator
85 /// decl-specifier-seq ref-qualifier[opt] '[' identifier-list ']'
87 /// In any of the above cases there can be a preceding attribute-specifier-seq,
88 /// but the caller is expected to handle that.
89 bool Parser::isCXXSimpleDeclaration(bool AllowForRangeDecl) {
91 // There is an ambiguity in the grammar involving expression-statements and
92 // declarations: An expression-statement with a function-style explicit type
93 // conversion (5.2.3) as its leftmost subexpression can be indistinguishable
94 // from a declaration where the first declarator starts with a '('. In those
95 // cases the statement is a declaration. [Note: To disambiguate, the whole
96 // statement might have to be examined to determine if it is an
97 // expression-statement or a declaration].
100 // The disambiguation is purely syntactic; that is, the meaning of the names
101 // occurring in such a statement, beyond whether they are type-names or not,
102 // is not generally used in or changed by the disambiguation. Class
103 // templates are instantiated as necessary to determine if a qualified name
104 // is a type-name. Disambiguation precedes parsing, and a statement
105 // disambiguated as a declaration may be an ill-formed declaration.
107 // We don't have to parse all of the decl-specifier-seq part. There's only
108 // an ambiguity if the first decl-specifier is
109 // simple-type-specifier/typename-specifier followed by a '(', which may
110 // indicate a function-style cast expression.
111 // isCXXDeclarationSpecifier will return TPResult::Ambiguous only in such
114 bool InvalidAsDeclaration = false;
115 TPResult TPR = isCXXDeclarationSpecifier(TPResult::False,
116 &InvalidAsDeclaration);
117 if (TPR != TPResult::Ambiguous)
118 return TPR != TPResult::False; // Returns true for TPResult::True or
121 // FIXME: TryParseSimpleDeclaration doesn't look past the first initializer,
122 // and so gets some cases wrong. We can't carry on if we've already seen
123 // something which makes this statement invalid as a declaration in this case,
124 // since it can cause us to misparse valid code. Revisit this once
125 // TryParseInitDeclaratorList is fixed.
126 if (InvalidAsDeclaration)
129 // FIXME: Add statistics about the number of ambiguous statements encountered
130 // and how they were resolved (number of declarations+number of expressions).
132 // Ok, we have a simple-type-specifier/typename-specifier followed by a '(',
133 // or an identifier which doesn't resolve as anything. We need tentative
137 RevertingTentativeParsingAction PA(*this);
138 TPR = TryParseSimpleDeclaration(AllowForRangeDecl);
141 // In case of an error, let the declaration parsing code handle it.
142 if (TPR == TPResult::Error)
145 // Declarations take precedence over expressions.
146 if (TPR == TPResult::Ambiguous)
147 TPR = TPResult::True;
149 assert(TPR == TPResult::True || TPR == TPResult::False);
150 return TPR == TPResult::True;
153 /// Try to consume a token sequence that we've already identified as
154 /// (potentially) starting a decl-specifier.
155 Parser::TPResult Parser::TryConsumeDeclarationSpecifier() {
156 switch (Tok.getKind()) {
157 case tok::kw__Atomic:
158 if (NextToken().isNot(tok::l_paren)) {
164 case tok::kw___attribute:
165 case tok::kw___underlying_type: {
167 if (Tok.isNot(tok::l_paren))
168 return TPResult::Error;
170 if (!SkipUntil(tok::r_paren))
171 return TPResult::Error;
178 case tok::kw___interface:
180 // elaborated-type-specifier:
181 // class-key attribute-specifier-seq[opt]
182 // nested-name-specifier[opt] identifier
183 // class-key nested-name-specifier[opt] template[opt] simple-template-id
184 // enum nested-name-specifier[opt] identifier
186 // FIXME: We don't support class-specifiers nor enum-specifiers here.
190 while (Tok.isOneOf(tok::l_square, tok::kw___attribute, tok::kw___declspec,
192 if (Tok.is(tok::l_square)) {
194 if (!SkipUntil(tok::r_square))
195 return TPResult::Error;
198 if (Tok.isNot(tok::l_paren))
199 return TPResult::Error;
201 if (!SkipUntil(tok::r_paren))
202 return TPResult::Error;
206 if (Tok.isOneOf(tok::identifier, tok::coloncolon, tok::kw_decltype,
207 tok::annot_template_id) &&
208 TryAnnotateCXXScopeToken())
209 return TPResult::Error;
210 if (Tok.is(tok::annot_cxxscope))
211 ConsumeAnnotationToken();
212 if (Tok.is(tok::identifier))
214 else if (Tok.is(tok::annot_template_id))
215 ConsumeAnnotationToken();
217 return TPResult::Error;
220 case tok::annot_cxxscope:
221 ConsumeAnnotationToken();
226 if (getLangOpts().ObjC1 && Tok.is(tok::less))
227 return TryParseProtocolQualifiers();
231 return TPResult::Ambiguous;
234 /// simple-declaration:
235 /// decl-specifier-seq init-declarator-list[opt] ';'
237 /// (if AllowForRangeDecl specified)
238 /// for ( for-range-declaration : for-range-initializer ) statement
239 /// for-range-declaration:
240 /// attribute-specifier-seqopt type-specifier-seq declarator
242 Parser::TPResult Parser::TryParseSimpleDeclaration(bool AllowForRangeDecl) {
243 if (TryConsumeDeclarationSpecifier() == TPResult::Error)
244 return TPResult::Error;
246 // Two decl-specifiers in a row conclusively disambiguate this as being a
247 // simple-declaration. Don't bother calling isCXXDeclarationSpecifier in the
248 // overwhelmingly common case that the next token is a '('.
249 if (Tok.isNot(tok::l_paren)) {
250 TPResult TPR = isCXXDeclarationSpecifier();
251 if (TPR == TPResult::Ambiguous)
252 return TPResult::True;
253 if (TPR == TPResult::True || TPR == TPResult::Error)
255 assert(TPR == TPResult::False);
258 TPResult TPR = TryParseInitDeclaratorList();
259 if (TPR != TPResult::Ambiguous)
262 if (Tok.isNot(tok::semi) && (!AllowForRangeDecl || Tok.isNot(tok::colon)))
263 return TPResult::False;
265 return TPResult::Ambiguous;
268 /// Tentatively parse an init-declarator-list in order to disambiguate it from
271 /// init-declarator-list:
273 /// init-declarator-list ',' init-declarator
276 /// declarator initializer[opt]
277 /// [GNU] declarator simple-asm-expr[opt] attributes[opt] initializer[opt]
280 /// brace-or-equal-initializer
281 /// '(' expression-list ')'
283 /// brace-or-equal-initializer:
284 /// '=' initializer-clause
285 /// [C++11] braced-init-list
287 /// initializer-clause:
288 /// assignment-expression
291 /// braced-init-list:
292 /// '{' initializer-list ','[opt] '}'
295 Parser::TPResult Parser::TryParseInitDeclaratorList() {
298 TPResult TPR = TryParseDeclarator(false/*mayBeAbstract*/);
299 if (TPR != TPResult::Ambiguous)
302 // [GNU] simple-asm-expr[opt] attributes[opt]
303 if (Tok.isOneOf(tok::kw_asm, tok::kw___attribute))
304 return TPResult::True;
307 if (Tok.is(tok::l_paren)) {
308 // Parse through the parens.
310 if (!SkipUntil(tok::r_paren, StopAtSemi))
311 return TPResult::Error;
312 } else if (Tok.is(tok::l_brace)) {
313 // A left-brace here is sufficient to disambiguate the parse; an
314 // expression can never be followed directly by a braced-init-list.
315 return TPResult::True;
316 } else if (Tok.is(tok::equal) || isTokIdentifier_in()) {
317 // MSVC and g++ won't examine the rest of declarators if '=' is
318 // encountered; they just conclude that we have a declaration.
319 // EDG parses the initializer completely, which is the proper behavior
322 // At present, Clang follows MSVC and g++, since the parser does not have
323 // the ability to parse an expression fully without recording the
324 // results of that parse.
325 // FIXME: Handle this case correctly.
327 // Also allow 'in' after an Objective-C declaration as in:
328 // for (int (^b)(void) in array). Ideally this should be done in the
329 // context of parsing for-init-statement of a foreach statement only. But,
330 // in any other context 'in' is invalid after a declaration and parser
331 // issues the error regardless of outcome of this decision.
332 // FIXME: Change if above assumption does not hold.
333 return TPResult::True;
336 if (!TryConsumeToken(tok::comma))
340 return TPResult::Ambiguous;
343 struct Parser::ConditionDeclarationOrInitStatementState {
345 bool CanBeExpression = true;
346 bool CanBeCondition = true;
347 bool CanBeInitStatement;
349 ConditionDeclarationOrInitStatementState(Parser &P, bool CanBeInitStatement)
350 : P(P), CanBeInitStatement(CanBeInitStatement) {}
352 void markNotExpression() {
353 CanBeExpression = false;
355 if (CanBeCondition && CanBeInitStatement) {
356 // FIXME: Unify the parsing codepaths for condition variables and
357 // simple-declarations so that we don't need to eagerly figure out which
358 // kind we have here. (Just parse init-declarators until we reach a
359 // semicolon or right paren.)
360 RevertingTentativeParsingAction PA(P);
361 P.SkipUntil(tok::r_paren, tok::semi, StopBeforeMatch);
362 if (P.Tok.isNot(tok::r_paren))
363 CanBeCondition = false;
364 if (P.Tok.isNot(tok::semi))
365 CanBeInitStatement = false;
369 bool markNotCondition() {
370 CanBeCondition = false;
371 return !CanBeInitStatement || !CanBeExpression;
374 bool update(TPResult IsDecl) {
379 case TPResult::False:
380 CanBeCondition = CanBeInitStatement = false;
382 case TPResult::Ambiguous:
384 case TPResult::Error:
385 CanBeExpression = CanBeCondition = CanBeInitStatement = false;
388 llvm_unreachable("unknown tentative parse result");
391 ConditionOrInitStatement result() const {
392 assert(CanBeExpression + CanBeCondition + CanBeInitStatement < 2 &&
393 "result called but not yet resolved");
395 return ConditionOrInitStatement::Expression;
397 return ConditionOrInitStatement::ConditionDecl;
398 if (CanBeInitStatement)
399 return ConditionOrInitStatement::InitStmtDecl;
400 return ConditionOrInitStatement::Error;
404 /// \brief Disambiguates between a declaration in a condition, a
405 /// simple-declaration in an init-statement, and an expression for
406 /// a condition of a if/switch statement.
410 /// type-specifier-seq declarator '=' assignment-expression
411 /// [C++11] type-specifier-seq declarator '=' initializer-clause
412 /// [C++11] type-specifier-seq declarator braced-init-list
413 /// [GNU] type-specifier-seq declarator simple-asm-expr[opt] attributes[opt]
414 /// '=' assignment-expression
415 /// simple-declaration:
416 /// decl-specifier-seq init-declarator-list[opt] ';'
418 /// Note that, unlike isCXXSimpleDeclaration, we must disambiguate all the way
419 /// to the ';' to disambiguate cases like 'int(x))' (an expression) from
420 /// 'int(x);' (a simple-declaration in an init-statement).
421 Parser::ConditionOrInitStatement
422 Parser::isCXXConditionDeclarationOrInitStatement(bool CanBeInitStatement) {
423 ConditionDeclarationOrInitStatementState State(*this, CanBeInitStatement);
425 if (State.update(isCXXDeclarationSpecifier()))
426 return State.result();
428 // It might be a declaration; we need tentative parsing.
429 RevertingTentativeParsingAction PA(*this);
431 // FIXME: A tag definition unambiguously tells us this is an init-statement.
432 if (State.update(TryConsumeDeclarationSpecifier()))
433 return State.result();
434 assert(Tok.is(tok::l_paren) && "Expected '('");
437 // Consume a declarator.
438 if (State.update(TryParseDeclarator(false/*mayBeAbstract*/)))
439 return State.result();
441 // Attributes, asm label, or an initializer imply this is not an expression.
442 // FIXME: Disambiguate properly after an = instead of assuming that it's a
443 // valid declaration.
444 if (Tok.isOneOf(tok::equal, tok::kw_asm, tok::kw___attribute) ||
445 (getLangOpts().CPlusPlus11 && Tok.is(tok::l_brace))) {
446 State.markNotExpression();
447 return State.result();
450 // At this point, it can't be a condition any more, because a condition
451 // must have a brace-or-equal-initializer.
452 if (State.markNotCondition())
453 return State.result();
455 // A parenthesized initializer could be part of an expression or a
456 // simple-declaration.
457 if (Tok.is(tok::l_paren)) {
459 SkipUntil(tok::r_paren, StopAtSemi);
462 if (!TryConsumeToken(tok::comma))
466 // We reached the end. If it can now be some kind of decl, then it is.
467 if (State.CanBeCondition && Tok.is(tok::r_paren))
468 return ConditionOrInitStatement::ConditionDecl;
469 else if (State.CanBeInitStatement && Tok.is(tok::semi))
470 return ConditionOrInitStatement::InitStmtDecl;
472 return ConditionOrInitStatement::Expression;
475 /// \brief Determine whether the next set of tokens contains a type-id.
477 /// The context parameter states what context we're parsing right
478 /// now, which affects how this routine copes with the token
479 /// following the type-id. If the context is TypeIdInParens, we have
480 /// already parsed the '(' and we will cease lookahead when we hit
481 /// the corresponding ')'. If the context is
482 /// TypeIdAsTemplateArgument, we've already parsed the '<' or ','
483 /// before this template argument, and will cease lookahead when we
484 /// hit a '>', '>>' (in C++0x), or ','; or, in C++0x, an ellipsis immediately
485 /// preceding such. Returns true for a type-id and false for an expression.
486 /// If during the disambiguation process a parsing error is encountered,
487 /// the function returns true to let the declaration parsing code handle it.
490 /// type-specifier-seq abstract-declarator[opt]
492 bool Parser::isCXXTypeId(TentativeCXXTypeIdContext Context, bool &isAmbiguous) {
497 // The ambiguity arising from the similarity between a function-style cast and
498 // a type-id can occur in different contexts. The ambiguity appears as a
499 // choice between a function-style cast expression and a declaration of a
500 // type. The resolution is that any construct that could possibly be a type-id
501 // in its syntactic context shall be considered a type-id.
503 TPResult TPR = isCXXDeclarationSpecifier();
504 if (TPR != TPResult::Ambiguous)
505 return TPR != TPResult::False; // Returns true for TPResult::True or
508 // FIXME: Add statistics about the number of ambiguous statements encountered
509 // and how they were resolved (number of declarations+number of expressions).
511 // Ok, we have a simple-type-specifier/typename-specifier followed by a '('.
512 // We need tentative parsing...
514 RevertingTentativeParsingAction PA(*this);
516 // type-specifier-seq
517 TryConsumeDeclarationSpecifier();
518 assert(Tok.is(tok::l_paren) && "Expected '('");
521 TPR = TryParseDeclarator(true/*mayBeAbstract*/, false/*mayHaveIdentifier*/);
523 // In case of an error, let the declaration parsing code handle it.
524 if (TPR == TPResult::Error)
525 TPR = TPResult::True;
527 if (TPR == TPResult::Ambiguous) {
528 // We are supposed to be inside parens, so if after the abstract declarator
529 // we encounter a ')' this is a type-id, otherwise it's an expression.
530 if (Context == TypeIdInParens && Tok.is(tok::r_paren)) {
531 TPR = TPResult::True;
534 // We are supposed to be inside a template argument, so if after
535 // the abstract declarator we encounter a '>', '>>' (in C++0x), or
536 // ','; or, in C++0x, an ellipsis immediately preceding such, this
537 // is a type-id. Otherwise, it's an expression.
538 } else if (Context == TypeIdAsTemplateArgument &&
539 (Tok.isOneOf(tok::greater, tok::comma) ||
540 (getLangOpts().CPlusPlus11 &&
541 (Tok.is(tok::greatergreater) ||
542 (Tok.is(tok::ellipsis) &&
543 NextToken().isOneOf(tok::greater, tok::greatergreater,
545 TPR = TPResult::True;
549 TPR = TPResult::False;
552 assert(TPR == TPResult::True || TPR == TPResult::False);
553 return TPR == TPResult::True;
556 /// \brief Returns true if this is a C++11 attribute-specifier. Per
557 /// C++11 [dcl.attr.grammar]p6, two consecutive left square bracket tokens
558 /// always introduce an attribute. In Objective-C++11, this rule does not
559 /// apply if either '[' begins a message-send.
561 /// If Disambiguate is true, we try harder to determine whether a '[[' starts
562 /// an attribute-specifier, and return CAK_InvalidAttributeSpecifier if not.
564 /// If OuterMightBeMessageSend is true, we assume the outer '[' is either an
565 /// Obj-C message send or the start of an attribute. Otherwise, we assume it
566 /// is not an Obj-C message send.
568 /// C++11 [dcl.attr.grammar]:
570 /// attribute-specifier:
571 /// '[' '[' attribute-list ']' ']'
572 /// alignment-specifier
576 /// attribute-list ',' attribute[opt]
578 /// attribute-list ',' attribute '...'
581 /// attribute-token attribute-argument-clause[opt]
585 /// identifier '::' identifier
587 /// attribute-argument-clause:
588 /// '(' balanced-token-seq ')'
589 Parser::CXX11AttributeKind
590 Parser::isCXX11AttributeSpecifier(bool Disambiguate,
591 bool OuterMightBeMessageSend) {
592 if (Tok.is(tok::kw_alignas))
593 return CAK_AttributeSpecifier;
595 if (Tok.isNot(tok::l_square) || NextToken().isNot(tok::l_square))
596 return CAK_NotAttributeSpecifier;
598 // No tentative parsing if we don't need to look for ']]' or a lambda.
599 if (!Disambiguate && !getLangOpts().ObjC1)
600 return CAK_AttributeSpecifier;
602 RevertingTentativeParsingAction PA(*this);
604 // Opening brackets were checked for above.
607 // Outside Obj-C++11, treat anything with a matching ']]' as an attribute.
608 if (!getLangOpts().ObjC1) {
611 bool IsAttribute = SkipUntil(tok::r_square);
612 IsAttribute &= Tok.is(tok::r_square);
614 return IsAttribute ? CAK_AttributeSpecifier : CAK_InvalidAttributeSpecifier;
617 // In Obj-C++11, we need to distinguish four situations:
618 // 1a) int x[[attr]]; C++11 attribute.
619 // 1b) [[attr]]; C++11 statement attribute.
620 // 2) int x[[obj](){ return 1; }()]; Lambda in array size/index.
621 // 3a) int x[[obj get]]; Message send in array size/index.
622 // 3b) [[Class alloc] init]; Message send in message send.
623 // 4) [[obj]{ return self; }() doStuff]; Lambda in message send.
624 // (1) is an attribute, (2) is ill-formed, and (3) and (4) are accepted.
626 // If we have a lambda-introducer, then this is definitely not a message send.
627 // FIXME: If this disambiguation is too slow, fold the tentative lambda parse
628 // into the tentative attribute parse below.
629 LambdaIntroducer Intro;
630 if (!TryParseLambdaIntroducer(Intro)) {
631 // A lambda cannot end with ']]', and an attribute must.
632 bool IsAttribute = Tok.is(tok::r_square);
635 // Case 1: C++11 attribute.
636 return CAK_AttributeSpecifier;
638 if (OuterMightBeMessageSend)
639 // Case 4: Lambda in message send.
640 return CAK_NotAttributeSpecifier;
642 // Case 2: Lambda in array size / index.
643 return CAK_InvalidAttributeSpecifier;
648 // If we don't have a lambda-introducer, then we have an attribute or a
650 bool IsAttribute = true;
651 while (Tok.isNot(tok::r_square)) {
652 if (Tok.is(tok::comma)) {
653 // Case 1: Stray commas can only occur in attributes.
654 return CAK_AttributeSpecifier;
657 // Parse the attribute-token, if present.
658 // C++11 [dcl.attr.grammar]:
659 // If a keyword or an alternative token that satisfies the syntactic
660 // requirements of an identifier is contained in an attribute-token,
661 // it is considered an identifier.
663 if (!TryParseCXX11AttributeIdentifier(Loc)) {
667 if (Tok.is(tok::coloncolon)) {
669 if (!TryParseCXX11AttributeIdentifier(Loc)) {
675 // Parse the attribute-argument-clause, if present.
676 if (Tok.is(tok::l_paren)) {
678 if (!SkipUntil(tok::r_paren)) {
684 TryConsumeToken(tok::ellipsis);
686 if (!TryConsumeToken(tok::comma))
690 // An attribute must end ']]'.
692 if (Tok.is(tok::r_square)) {
694 IsAttribute = Tok.is(tok::r_square);
701 // Case 1: C++11 statement attribute.
702 return CAK_AttributeSpecifier;
704 // Case 3: Message send.
705 return CAK_NotAttributeSpecifier;
708 Parser::TPResult Parser::TryParsePtrOperatorSeq() {
710 if (Tok.isOneOf(tok::coloncolon, tok::identifier))
711 if (TryAnnotateCXXScopeToken(true))
712 return TPResult::Error;
714 if (Tok.isOneOf(tok::star, tok::amp, tok::caret, tok::ampamp) ||
715 (Tok.is(tok::annot_cxxscope) && NextToken().is(tok::star))) {
718 while (Tok.isOneOf(tok::kw_const, tok::kw_volatile, tok::kw_restrict,
719 tok::kw__Nonnull, tok::kw__Nullable,
720 tok::kw__Null_unspecified))
723 return TPResult::True;
728 /// operator-function-id:
729 /// 'operator' operator
732 /// new delete new[] delete[] + - * / % ^ [...]
734 /// conversion-function-id:
735 /// 'operator' conversion-type-id
737 /// conversion-type-id:
738 /// type-specifier-seq conversion-declarator[opt]
740 /// conversion-declarator:
741 /// ptr-operator conversion-declarator[opt]
743 /// literal-operator-id:
744 /// 'operator' string-literal identifier
745 /// 'operator' user-defined-string-literal
746 Parser::TPResult Parser::TryParseOperatorId() {
747 assert(Tok.is(tok::kw_operator));
750 // Maybe this is an operator-function-id.
751 switch (Tok.getKind()) {
752 case tok::kw_new: case tok::kw_delete:
754 if (Tok.is(tok::l_square) && NextToken().is(tok::r_square)) {
758 return TPResult::True;
760 #define OVERLOADED_OPERATOR(Name, Spelling, Token, Unary, Binary, MemOnly) \
762 #define OVERLOADED_OPERATOR_MULTI(Name, Spelling, Unary, Binary, MemOnly)
763 #include "clang/Basic/OperatorKinds.def"
765 return TPResult::True;
768 if (NextToken().is(tok::r_square)) {
771 return TPResult::True;
776 if (NextToken().is(tok::r_paren)) {
779 return TPResult::True;
787 // Maybe this is a literal-operator-id.
788 if (getLangOpts().CPlusPlus11 && isTokenStringLiteral()) {
789 bool FoundUDSuffix = false;
791 FoundUDSuffix |= Tok.hasUDSuffix();
792 ConsumeStringToken();
793 } while (isTokenStringLiteral());
795 if (!FoundUDSuffix) {
796 if (Tok.is(tok::identifier))
799 return TPResult::Error;
801 return TPResult::True;
804 // Maybe this is a conversion-function-id.
805 bool AnyDeclSpecifiers = false;
807 TPResult TPR = isCXXDeclarationSpecifier();
808 if (TPR == TPResult::Error)
810 if (TPR == TPResult::False) {
811 if (!AnyDeclSpecifiers)
812 return TPResult::Error;
815 if (TryConsumeDeclarationSpecifier() == TPResult::Error)
816 return TPResult::Error;
817 AnyDeclSpecifiers = true;
819 return TryParsePtrOperatorSeq();
823 /// direct-declarator
824 /// ptr-operator declarator
826 /// direct-declarator:
828 /// direct-declarator '(' parameter-declaration-clause ')'
829 /// cv-qualifier-seq[opt] exception-specification[opt]
830 /// direct-declarator '[' constant-expression[opt] ']'
831 /// '(' declarator ')'
832 /// [GNU] '(' attributes declarator ')'
834 /// abstract-declarator:
835 /// ptr-operator abstract-declarator[opt]
836 /// direct-abstract-declarator
838 /// direct-abstract-declarator:
839 /// direct-abstract-declarator[opt]
840 /// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
841 /// exception-specification[opt]
842 /// direct-abstract-declarator[opt] '[' constant-expression[opt] ']'
843 /// '(' abstract-declarator ')'
847 /// '*' cv-qualifier-seq[opt]
849 /// [C++0x] '&&' [TODO]
850 /// '::'[opt] nested-name-specifier '*' cv-qualifier-seq[opt]
852 /// cv-qualifier-seq:
853 /// cv-qualifier cv-qualifier-seq[opt]
860 /// '...'[opt] id-expression
864 /// qualified-id [TODO]
868 /// operator-function-id
869 /// conversion-function-id
870 /// literal-operator-id
871 /// '~' class-name [TODO]
872 /// '~' decltype-specifier [TODO]
873 /// template-id [TODO]
875 Parser::TPResult Parser::TryParseDeclarator(bool mayBeAbstract,
876 bool mayHaveIdentifier) {
879 // ptr-operator declarator
880 if (TryParsePtrOperatorSeq() == TPResult::Error)
881 return TPResult::Error;
883 // direct-declarator:
884 // direct-abstract-declarator:
885 if (Tok.is(tok::ellipsis))
888 if ((Tok.isOneOf(tok::identifier, tok::kw_operator) ||
889 (Tok.is(tok::annot_cxxscope) && (NextToken().is(tok::identifier) ||
890 NextToken().is(tok::kw_operator)))) &&
893 if (Tok.is(tok::annot_cxxscope))
894 ConsumeAnnotationToken();
895 else if (Tok.is(tok::identifier))
896 TentativelyDeclaredIdentifiers.push_back(Tok.getIdentifierInfo());
897 if (Tok.is(tok::kw_operator)) {
898 if (TryParseOperatorId() == TPResult::Error)
899 return TPResult::Error;
902 } else if (Tok.is(tok::l_paren)) {
905 (Tok.is(tok::r_paren) || // 'int()' is a function.
906 // 'int(...)' is a function.
907 (Tok.is(tok::ellipsis) && NextToken().is(tok::r_paren)) ||
908 isDeclarationSpecifier())) { // 'int(int)' is a function.
909 // '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
910 // exception-specification[opt]
911 TPResult TPR = TryParseFunctionDeclarator();
912 if (TPR != TPResult::Ambiguous)
915 // '(' declarator ')'
916 // '(' attributes declarator ')'
917 // '(' abstract-declarator ')'
918 if (Tok.isOneOf(tok::kw___attribute, tok::kw___declspec, tok::kw___cdecl,
919 tok::kw___stdcall, tok::kw___fastcall, tok::kw___thiscall,
920 tok::kw___regcall, tok::kw___vectorcall))
921 return TPResult::True; // attributes indicate declaration
922 TPResult TPR = TryParseDeclarator(mayBeAbstract, mayHaveIdentifier);
923 if (TPR != TPResult::Ambiguous)
925 if (Tok.isNot(tok::r_paren))
926 return TPResult::False;
929 } else if (!mayBeAbstract) {
930 return TPResult::False;
934 TPResult TPR(TPResult::Ambiguous);
936 if (Tok.is(tok::l_paren)) {
937 // Check whether we have a function declarator or a possible ctor-style
938 // initializer that follows the declarator. Note that ctor-style
939 // initializers are not possible in contexts where abstract declarators
941 if (!mayBeAbstract && !isCXXFunctionDeclarator())
944 // direct-declarator '(' parameter-declaration-clause ')'
945 // cv-qualifier-seq[opt] exception-specification[opt]
947 TPR = TryParseFunctionDeclarator();
948 } else if (Tok.is(tok::l_square)) {
949 // direct-declarator '[' constant-expression[opt] ']'
950 // direct-abstract-declarator[opt] '[' constant-expression[opt] ']'
951 TPR = TryParseBracketDeclarator();
956 if (TPR != TPResult::Ambiguous)
960 return TPResult::Ambiguous;
964 Parser::isExpressionOrTypeSpecifierSimple(tok::TokenKind Kind) {
966 // Obviously starts an expression.
967 case tok::numeric_constant:
968 case tok::char_constant:
969 case tok::wide_char_constant:
970 case tok::utf8_char_constant:
971 case tok::utf16_char_constant:
972 case tok::utf32_char_constant:
973 case tok::string_literal:
974 case tok::wide_string_literal:
975 case tok::utf8_string_literal:
976 case tok::utf16_string_literal:
977 case tok::utf32_string_literal:
986 case tok::minusminus:
990 case tok::kw___func__:
991 case tok::kw_const_cast:
993 case tok::kw_dynamic_cast:
996 case tok::kw_operator:
997 case tok::kw_reinterpret_cast:
998 case tok::kw_static_cast:
1002 case tok::kw_typeid:
1003 case tok::kw_alignof:
1004 case tok::kw_noexcept:
1005 case tok::kw_nullptr:
1006 case tok::kw__Alignof:
1007 case tok::kw___null:
1008 case tok::kw___alignof:
1009 case tok::kw___builtin_choose_expr:
1010 case tok::kw___builtin_offsetof:
1011 case tok::kw___builtin_va_arg:
1012 case tok::kw___imag:
1013 case tok::kw___real:
1014 case tok::kw___FUNCTION__:
1015 case tok::kw___FUNCDNAME__:
1016 case tok::kw___FUNCSIG__:
1017 case tok::kw_L__FUNCTION__:
1018 case tok::kw___PRETTY_FUNCTION__:
1019 case tok::kw___uuidof:
1020 #define TYPE_TRAIT(N,Spelling,K) \
1021 case tok::kw_##Spelling:
1022 #include "clang/Basic/TokenKinds.def"
1023 return TPResult::True;
1025 // Obviously starts a type-specifier-seq:
1028 case tok::kw_double:
1029 case tok::kw__Float16:
1030 case tok::kw___float128:
1036 case tok::kw___int64:
1037 case tok::kw___int128:
1038 case tok::kw_restrict:
1040 case tok::kw_signed:
1041 case tok::kw_struct:
1043 case tok::kw_unsigned:
1045 case tok::kw_volatile:
1047 case tok::kw__Complex:
1049 case tok::kw_typename:
1050 case tok::kw_wchar_t:
1051 case tok::kw_char16_t:
1052 case tok::kw_char32_t:
1053 case tok::kw__Decimal32:
1054 case tok::kw__Decimal64:
1055 case tok::kw__Decimal128:
1056 case tok::kw___interface:
1057 case tok::kw___thread:
1058 case tok::kw_thread_local:
1059 case tok::kw__Thread_local:
1060 case tok::kw_typeof:
1061 case tok::kw___underlying_type:
1062 case tok::kw___cdecl:
1063 case tok::kw___stdcall:
1064 case tok::kw___fastcall:
1065 case tok::kw___thiscall:
1066 case tok::kw___regcall:
1067 case tok::kw___vectorcall:
1068 case tok::kw___unaligned:
1069 case tok::kw___vector:
1070 case tok::kw___pixel:
1071 case tok::kw___bool:
1072 case tok::kw__Atomic:
1073 #define GENERIC_IMAGE_TYPE(ImgType, Id) case tok::kw_##ImgType##_t:
1074 #include "clang/Basic/OpenCLImageTypes.def"
1075 case tok::kw___unknown_anytype:
1076 return TPResult::False;
1082 return TPResult::Ambiguous;
1085 bool Parser::isTentativelyDeclared(IdentifierInfo *II) {
1086 return std::find(TentativelyDeclaredIdentifiers.begin(),
1087 TentativelyDeclaredIdentifiers.end(), II)
1088 != TentativelyDeclaredIdentifiers.end();
1092 class TentativeParseCCC : public CorrectionCandidateCallback {
1094 TentativeParseCCC(const Token &Next) {
1095 WantRemainingKeywords = false;
1096 WantTypeSpecifiers = Next.isOneOf(tok::l_paren, tok::r_paren, tok::greater,
1097 tok::l_brace, tok::identifier);
1100 bool ValidateCandidate(const TypoCorrection &Candidate) override {
1101 // Reject any candidate that only resolves to instance members since they
1102 // aren't viable as standalone identifiers instead of member references.
1103 if (Candidate.isResolved() && !Candidate.isKeyword() &&
1104 std::all_of(Candidate.begin(), Candidate.end(),
1105 [](NamedDecl *ND) { return ND->isCXXInstanceMember(); }))
1108 return CorrectionCandidateCallback::ValidateCandidate(Candidate);
1112 /// isCXXDeclarationSpecifier - Returns TPResult::True if it is a declaration
1113 /// specifier, TPResult::False if it is not, TPResult::Ambiguous if it could
1114 /// be either a decl-specifier or a function-style cast, and TPResult::Error
1115 /// if a parsing error was found and reported.
1117 /// If HasMissingTypename is provided, a name with a dependent scope specifier
1118 /// will be treated as ambiguous if the 'typename' keyword is missing. If this
1119 /// happens, *HasMissingTypename will be set to 'true'. This will also be used
1120 /// as an indicator that undeclared identifiers (which will trigger a later
1121 /// parse error) should be treated as types. Returns TPResult::Ambiguous in
1125 /// storage-class-specifier
1127 /// function-specifier
1130 /// [C++11] 'constexpr'
1131 /// [GNU] attributes declaration-specifiers[opt]
1133 /// storage-class-specifier:
1139 /// [GNU] '__thread'
1140 /// [C++11] 'thread_local'
1141 /// [C11] '_Thread_local'
1143 /// function-specifier:
1152 /// simple-type-specifier
1155 /// elaborated-type-specifier
1156 /// typename-specifier
1159 /// simple-type-specifier:
1160 /// '::'[opt] nested-name-specifier[opt] type-name
1161 /// '::'[opt] nested-name-specifier 'template'
1162 /// simple-template-id [TODO]
1174 /// [GNU] typeof-specifier
1175 /// [GNU] '_Complex'
1177 /// [GNU] '__auto_type'
1178 /// [C++11] 'decltype' ( expression )
1179 /// [C++1y] 'decltype' ( 'auto' )
1186 /// elaborated-type-specifier:
1187 /// class-key '::'[opt] nested-name-specifier[opt] identifier
1188 /// class-key '::'[opt] nested-name-specifier[opt] 'template'[opt]
1189 /// simple-template-id
1190 /// 'enum' '::'[opt] nested-name-specifier[opt] identifier
1196 /// 'enum' identifier[opt] '{' enumerator-list[opt] '}'
1197 /// 'enum' identifier[opt] '{' enumerator-list ',' '}'
1199 /// class-specifier:
1200 /// class-head '{' member-specification[opt] '}'
1203 /// class-key identifier[opt] base-clause[opt]
1204 /// class-key nested-name-specifier identifier base-clause[opt]
1205 /// class-key nested-name-specifier[opt] simple-template-id
1206 /// base-clause[opt]
1219 Parser::isCXXDeclarationSpecifier(Parser::TPResult BracedCastResult,
1220 bool *HasMissingTypename) {
1221 switch (Tok.getKind()) {
1222 case tok::identifier: {
1223 // Check for need to substitute AltiVec __vector keyword
1224 // for "vector" identifier.
1225 if (TryAltiVecVectorToken())
1226 return TPResult::True;
1228 const Token &Next = NextToken();
1229 // In 'foo bar', 'foo' is always a type name outside of Objective-C.
1230 if (!getLangOpts().ObjC1 && Next.is(tok::identifier))
1231 return TPResult::True;
1233 if (Next.isNot(tok::coloncolon) && Next.isNot(tok::less)) {
1234 // Determine whether this is a valid expression. If not, we will hit
1235 // a parse error one way or another. In that case, tell the caller that
1236 // this is ambiguous. Typo-correct to type and expression keywords and
1237 // to types and identifiers, in order to try to recover from errors.
1238 switch (TryAnnotateName(false /* no nested name specifier */,
1239 llvm::make_unique<TentativeParseCCC>(Next))) {
1241 return TPResult::Error;
1242 case ANK_TentativeDecl:
1243 return TPResult::False;
1244 case ANK_TemplateName:
1245 // A bare type template-name which can't be a template template
1246 // argument is an error, and was probably intended to be a type.
1247 return GreaterThanIsOperator ? TPResult::True : TPResult::False;
1248 case ANK_Unresolved:
1249 return HasMissingTypename ? TPResult::Ambiguous : TPResult::False;
1253 assert(Tok.isNot(tok::identifier) &&
1254 "TryAnnotateName succeeded without producing an annotation");
1256 // This might possibly be a type with a dependent scope specifier and
1257 // a missing 'typename' keyword. Don't use TryAnnotateName in this case,
1258 // since it will annotate as a primary expression, and we want to use the
1259 // "missing 'typename'" logic.
1260 if (TryAnnotateTypeOrScopeToken())
1261 return TPResult::Error;
1262 // If annotation failed, assume it's a non-type.
1263 // FIXME: If this happens due to an undeclared identifier, treat it as
1265 if (Tok.is(tok::identifier))
1266 return TPResult::False;
1269 // We annotated this token as something. Recurse to handle whatever we got.
1270 return isCXXDeclarationSpecifier(BracedCastResult, HasMissingTypename);
1273 case tok::kw_typename: // typename T::type
1274 // Annotate typenames and C++ scope specifiers. If we get one, just
1275 // recurse to handle whatever we get.
1276 if (TryAnnotateTypeOrScopeToken())
1277 return TPResult::Error;
1278 return isCXXDeclarationSpecifier(BracedCastResult, HasMissingTypename);
1280 case tok::coloncolon: { // ::foo::bar
1281 const Token &Next = NextToken();
1282 if (Next.isOneOf(tok::kw_new, // ::new
1283 tok::kw_delete)) // ::delete
1284 return TPResult::False;
1287 case tok::kw___super:
1288 case tok::kw_decltype:
1289 // Annotate typenames and C++ scope specifiers. If we get one, just
1290 // recurse to handle whatever we get.
1291 if (TryAnnotateTypeOrScopeToken())
1292 return TPResult::Error;
1293 return isCXXDeclarationSpecifier(BracedCastResult, HasMissingTypename);
1296 // storage-class-specifier
1298 // function-specifier
1302 case tok::kw_friend:
1303 case tok::kw_typedef:
1304 case tok::kw_constexpr:
1305 // storage-class-specifier
1306 case tok::kw_register:
1307 case tok::kw_static:
1308 case tok::kw_extern:
1309 case tok::kw_mutable:
1311 case tok::kw___thread:
1312 case tok::kw_thread_local:
1313 case tok::kw__Thread_local:
1314 // function-specifier
1315 case tok::kw_inline:
1316 case tok::kw_virtual:
1317 case tok::kw_explicit:
1320 case tok::kw___module_private__:
1323 case tok::kw___unknown_anytype:
1326 // simple-type-specifier
1329 // elaborated-type-specifier
1330 // typename-specifier
1334 // elaborated-type-specifier
1336 case tok::kw_struct:
1338 case tok::kw___interface:
1343 case tok::kw_volatile:
1346 case tok::kw_restrict:
1347 case tok::kw__Complex:
1348 case tok::kw___attribute:
1349 case tok::kw___auto_type:
1350 return TPResult::True;
1353 case tok::kw___declspec:
1354 case tok::kw___cdecl:
1355 case tok::kw___stdcall:
1356 case tok::kw___fastcall:
1357 case tok::kw___thiscall:
1358 case tok::kw___regcall:
1359 case tok::kw___vectorcall:
1361 case tok::kw___sptr:
1362 case tok::kw___uptr:
1363 case tok::kw___ptr64:
1364 case tok::kw___ptr32:
1365 case tok::kw___forceinline:
1366 case tok::kw___unaligned:
1367 case tok::kw__Nonnull:
1368 case tok::kw__Nullable:
1369 case tok::kw__Null_unspecified:
1370 case tok::kw___kindof:
1371 return TPResult::True;
1374 case tok::kw___pascal:
1375 return TPResult::True;
1378 case tok::kw___vector:
1379 return TPResult::True;
1381 case tok::annot_template_id: {
1382 TemplateIdAnnotation *TemplateId = takeTemplateIdAnnotation(Tok);
1383 if (TemplateId->Kind != TNK_Type_template)
1384 return TPResult::False;
1386 AnnotateTemplateIdTokenAsType();
1387 assert(Tok.is(tok::annot_typename));
1391 case tok::annot_cxxscope: // foo::bar or ::foo::bar, but already parsed
1392 // We've already annotated a scope; try to annotate a type.
1393 if (TryAnnotateTypeOrScopeToken())
1394 return TPResult::Error;
1395 if (!Tok.is(tok::annot_typename)) {
1396 // If the next token is an identifier or a type qualifier, then this
1397 // can't possibly be a valid expression either.
1398 if (Tok.is(tok::annot_cxxscope) && NextToken().is(tok::identifier)) {
1400 Actions.RestoreNestedNameSpecifierAnnotation(Tok.getAnnotationValue(),
1401 Tok.getAnnotationRange(),
1403 if (SS.getScopeRep() && SS.getScopeRep()->isDependent()) {
1404 RevertingTentativeParsingAction PA(*this);
1405 ConsumeAnnotationToken();
1407 bool isIdentifier = Tok.is(tok::identifier);
1408 TPResult TPR = TPResult::False;
1410 TPR = isCXXDeclarationSpecifier(BracedCastResult,
1411 HasMissingTypename);
1414 TPR == TPResult::True || TPR == TPResult::Error)
1415 return TPResult::Error;
1417 if (HasMissingTypename) {
1418 // We can't tell whether this is a missing 'typename' or a valid
1420 *HasMissingTypename = true;
1421 return TPResult::Ambiguous;
1424 // FIXME: Fails to either revert or commit the tentative parse!
1426 // Try to resolve the name. If it doesn't exist, assume it was
1427 // intended to name a type and keep disambiguating.
1428 switch (TryAnnotateName(false /* SS is not dependent */)) {
1430 return TPResult::Error;
1431 case ANK_TentativeDecl:
1432 return TPResult::False;
1433 case ANK_TemplateName:
1434 // A bare type template-name which can't be a template template
1435 // argument is an error, and was probably intended to be a type.
1436 return GreaterThanIsOperator ? TPResult::True : TPResult::False;
1437 case ANK_Unresolved:
1438 return HasMissingTypename ? TPResult::Ambiguous
1441 // Annotated it, check again.
1442 assert(Tok.isNot(tok::annot_cxxscope) ||
1443 NextToken().isNot(tok::identifier));
1444 return isCXXDeclarationSpecifier(BracedCastResult,
1445 HasMissingTypename);
1449 return TPResult::False;
1451 // If that succeeded, fallthrough into the generic simple-type-id case.
1454 // The ambiguity resides in a simple-type-specifier/typename-specifier
1455 // followed by a '('. The '(' could either be the start of:
1457 // direct-declarator:
1458 // '(' declarator ')'
1460 // direct-abstract-declarator:
1461 // '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
1462 // exception-specification[opt]
1463 // '(' abstract-declarator ')'
1465 // or part of a function-style cast expression:
1467 // simple-type-specifier '(' expression-list[opt] ')'
1470 // simple-type-specifier:
1472 case tok::annot_typename:
1474 // In Objective-C, we might have a protocol-qualified type.
1475 if (getLangOpts().ObjC1 && NextToken().is(tok::less)) {
1476 // Tentatively parse the protocol qualifiers.
1477 RevertingTentativeParsingAction PA(*this);
1478 ConsumeAnyToken(); // The type token
1480 TPResult TPR = TryParseProtocolQualifiers();
1481 bool isFollowedByParen = Tok.is(tok::l_paren);
1482 bool isFollowedByBrace = Tok.is(tok::l_brace);
1484 if (TPR == TPResult::Error)
1485 return TPResult::Error;
1487 if (isFollowedByParen)
1488 return TPResult::Ambiguous;
1490 if (getLangOpts().CPlusPlus11 && isFollowedByBrace)
1491 return BracedCastResult;
1493 return TPResult::True;
1498 case tok::kw_wchar_t:
1499 case tok::kw_char16_t:
1500 case tok::kw_char32_t:
1505 case tok::kw___int64:
1506 case tok::kw___int128:
1507 case tok::kw_signed:
1508 case tok::kw_unsigned:
1511 case tok::kw_double:
1512 case tok::kw__Float16:
1513 case tok::kw___float128:
1515 case tok::annot_decltype:
1516 if (NextToken().is(tok::l_paren))
1517 return TPResult::Ambiguous;
1519 // This is a function-style cast in all cases we disambiguate other than
1522 // enum E : int { a = 4 }; // enum
1523 // enum E : int { 4 }; // bit-field
1525 if (getLangOpts().CPlusPlus11 && NextToken().is(tok::l_brace))
1526 return BracedCastResult;
1528 if (isStartOfObjCClassMessageMissingOpenBracket())
1529 return TPResult::False;
1531 return TPResult::True;
1533 // GNU typeof support.
1534 case tok::kw_typeof: {
1535 if (NextToken().isNot(tok::l_paren))
1536 return TPResult::True;
1538 RevertingTentativeParsingAction PA(*this);
1540 TPResult TPR = TryParseTypeofSpecifier();
1541 bool isFollowedByParen = Tok.is(tok::l_paren);
1542 bool isFollowedByBrace = Tok.is(tok::l_brace);
1544 if (TPR == TPResult::Error)
1545 return TPResult::Error;
1547 if (isFollowedByParen)
1548 return TPResult::Ambiguous;
1550 if (getLangOpts().CPlusPlus11 && isFollowedByBrace)
1551 return BracedCastResult;
1553 return TPResult::True;
1556 // C++0x type traits support
1557 case tok::kw___underlying_type:
1558 return TPResult::True;
1561 case tok::kw__Atomic:
1562 return TPResult::True;
1565 return TPResult::False;
1569 bool Parser::isCXXDeclarationSpecifierAType() {
1570 switch (Tok.getKind()) {
1571 // typename-specifier
1572 case tok::annot_decltype:
1573 case tok::annot_template_id:
1574 case tok::annot_typename:
1575 case tok::kw_typeof:
1576 case tok::kw___underlying_type:
1579 // elaborated-type-specifier
1581 case tok::kw_struct:
1583 case tok::kw___interface:
1587 // simple-type-specifier
1589 case tok::kw_wchar_t:
1590 case tok::kw_char16_t:
1591 case tok::kw_char32_t:
1596 case tok::kw___int64:
1597 case tok::kw___int128:
1598 case tok::kw_signed:
1599 case tok::kw_unsigned:
1602 case tok::kw_double:
1603 case tok::kw__Float16:
1604 case tok::kw___float128:
1606 case tok::kw___unknown_anytype:
1607 case tok::kw___auto_type:
1611 return getLangOpts().CPlusPlus11;
1613 case tok::kw__Atomic:
1615 return NextToken().is(tok::l_paren);
1622 /// [GNU] typeof-specifier:
1623 /// 'typeof' '(' expressions ')'
1624 /// 'typeof' '(' type-name ')'
1626 Parser::TPResult Parser::TryParseTypeofSpecifier() {
1627 assert(Tok.is(tok::kw_typeof) && "Expected 'typeof'!");
1630 assert(Tok.is(tok::l_paren) && "Expected '('");
1631 // Parse through the parens after 'typeof'.
1633 if (!SkipUntil(tok::r_paren, StopAtSemi))
1634 return TPResult::Error;
1636 return TPResult::Ambiguous;
1639 /// [ObjC] protocol-qualifiers:
1640 //// '<' identifier-list '>'
1641 Parser::TPResult Parser::TryParseProtocolQualifiers() {
1642 assert(Tok.is(tok::less) && "Expected '<' for qualifier list");
1645 if (Tok.isNot(tok::identifier))
1646 return TPResult::Error;
1649 if (Tok.is(tok::comma)) {
1654 if (Tok.is(tok::greater)) {
1656 return TPResult::Ambiguous;
1660 return TPResult::Error;
1663 /// isCXXFunctionDeclarator - Disambiguates between a function declarator or
1664 /// a constructor-style initializer, when parsing declaration statements.
1665 /// Returns true for function declarator and false for constructor-style
1667 /// If during the disambiguation process a parsing error is encountered,
1668 /// the function returns true to let the declaration parsing code handle it.
1670 /// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
1671 /// exception-specification[opt]
1673 bool Parser::isCXXFunctionDeclarator(bool *IsAmbiguous) {
1676 // The ambiguity arising from the similarity between a function-style cast and
1677 // a declaration mentioned in 6.8 can also occur in the context of a
1678 // declaration. In that context, the choice is between a function declaration
1679 // with a redundant set of parentheses around a parameter name and an object
1680 // declaration with a function-style cast as the initializer. Just as for the
1681 // ambiguities mentioned in 6.8, the resolution is to consider any construct
1682 // that could possibly be a declaration a declaration.
1684 RevertingTentativeParsingAction PA(*this);
1687 bool InvalidAsDeclaration = false;
1688 TPResult TPR = TryParseParameterDeclarationClause(&InvalidAsDeclaration);
1689 if (TPR == TPResult::Ambiguous) {
1690 if (Tok.isNot(tok::r_paren))
1691 TPR = TPResult::False;
1693 const Token &Next = NextToken();
1694 if (Next.isOneOf(tok::amp, tok::ampamp, tok::kw_const, tok::kw_volatile,
1695 tok::kw_throw, tok::kw_noexcept, tok::l_square,
1696 tok::l_brace, tok::kw_try, tok::equal, tok::arrow) ||
1697 isCXX11VirtSpecifier(Next))
1698 // The next token cannot appear after a constructor-style initializer,
1699 // and can appear next in a function definition. This must be a function
1701 TPR = TPResult::True;
1702 else if (InvalidAsDeclaration)
1703 // Use the absence of 'typename' as a tie-breaker.
1704 TPR = TPResult::False;
1708 if (IsAmbiguous && TPR == TPResult::Ambiguous)
1709 *IsAmbiguous = true;
1711 // In case of an error, let the declaration parsing code handle it.
1712 return TPR != TPResult::False;
1715 /// parameter-declaration-clause:
1716 /// parameter-declaration-list[opt] '...'[opt]
1717 /// parameter-declaration-list ',' '...'
1719 /// parameter-declaration-list:
1720 /// parameter-declaration
1721 /// parameter-declaration-list ',' parameter-declaration
1723 /// parameter-declaration:
1724 /// attribute-specifier-seq[opt] decl-specifier-seq declarator attributes[opt]
1725 /// attribute-specifier-seq[opt] decl-specifier-seq declarator attributes[opt]
1726 /// '=' assignment-expression
1727 /// attribute-specifier-seq[opt] decl-specifier-seq abstract-declarator[opt]
1729 /// attribute-specifier-seq[opt] decl-specifier-seq abstract-declarator[opt]
1730 /// attributes[opt] '=' assignment-expression
1733 Parser::TryParseParameterDeclarationClause(bool *InvalidAsDeclaration,
1734 bool VersusTemplateArgument) {
1736 if (Tok.is(tok::r_paren))
1737 return TPResult::Ambiguous;
1739 // parameter-declaration-list[opt] '...'[opt]
1740 // parameter-declaration-list ',' '...'
1742 // parameter-declaration-list:
1743 // parameter-declaration
1744 // parameter-declaration-list ',' parameter-declaration
1748 if (Tok.is(tok::ellipsis)) {
1750 if (Tok.is(tok::r_paren))
1751 return TPResult::True; // '...)' is a sign of a function declarator.
1753 return TPResult::False;
1756 // An attribute-specifier-seq here is a sign of a function declarator.
1757 if (isCXX11AttributeSpecifier(/*Disambiguate*/false,
1758 /*OuterMightBeMessageSend*/true))
1759 return TPResult::True;
1761 ParsedAttributes attrs(AttrFactory);
1762 MaybeParseMicrosoftAttributes(attrs);
1764 // decl-specifier-seq
1765 // A parameter-declaration's initializer must be preceded by an '=', so
1766 // decl-specifier-seq '{' is not a parameter in C++11.
1767 TPResult TPR = isCXXDeclarationSpecifier(TPResult::False,
1768 InvalidAsDeclaration);
1770 if (VersusTemplateArgument && TPR == TPResult::True) {
1771 // Consume the decl-specifier-seq. We have to look past it, since a
1772 // type-id might appear here in a template argument.
1773 bool SeenType = false;
1775 SeenType |= isCXXDeclarationSpecifierAType();
1776 if (TryConsumeDeclarationSpecifier() == TPResult::Error)
1777 return TPResult::Error;
1779 // If we see a parameter name, this can't be a template argument.
1780 if (SeenType && Tok.is(tok::identifier))
1781 return TPResult::True;
1783 TPR = isCXXDeclarationSpecifier(TPResult::False,
1784 InvalidAsDeclaration);
1785 if (TPR == TPResult::Error)
1787 } while (TPR != TPResult::False);
1788 } else if (TPR == TPResult::Ambiguous) {
1789 // Disambiguate what follows the decl-specifier.
1790 if (TryConsumeDeclarationSpecifier() == TPResult::Error)
1791 return TPResult::Error;
1796 // abstract-declarator[opt]
1797 TPR = TryParseDeclarator(true/*mayBeAbstract*/);
1798 if (TPR != TPResult::Ambiguous)
1801 // [GNU] attributes[opt]
1802 if (Tok.is(tok::kw___attribute))
1803 return TPResult::True;
1805 // If we're disambiguating a template argument in a default argument in
1806 // a class definition versus a parameter declaration, an '=' here
1807 // disambiguates the parse one way or the other.
1808 // If this is a parameter, it must have a default argument because
1809 // (a) the previous parameter did, and
1810 // (b) this must be the first declaration of the function, so we can't
1811 // inherit any default arguments from elsewhere.
1812 // If we see an ')', then we've reached the end of a
1813 // parameter-declaration-clause, and the last param is missing its default
1815 if (VersusTemplateArgument)
1816 return Tok.isOneOf(tok::equal, tok::r_paren) ? TPResult::True
1819 if (Tok.is(tok::equal)) {
1820 // '=' assignment-expression
1821 // Parse through assignment-expression.
1822 // FIXME: assignment-expression may contain an unparenthesized comma.
1823 if (!SkipUntil(tok::comma, tok::r_paren, StopAtSemi | StopBeforeMatch))
1824 return TPResult::Error;
1827 if (Tok.is(tok::ellipsis)) {
1829 if (Tok.is(tok::r_paren))
1830 return TPResult::True; // '...)' is a sign of a function declarator.
1832 return TPResult::False;
1835 if (!TryConsumeToken(tok::comma))
1839 return TPResult::Ambiguous;
1842 /// TryParseFunctionDeclarator - We parsed a '(' and we want to try to continue
1843 /// parsing as a function declarator.
1844 /// If TryParseFunctionDeclarator fully parsed the function declarator, it will
1845 /// return TPResult::Ambiguous, otherwise it will return either False() or
1848 /// '(' parameter-declaration-clause ')' cv-qualifier-seq[opt]
1849 /// exception-specification[opt]
1851 /// exception-specification:
1852 /// 'throw' '(' type-id-list[opt] ')'
1854 Parser::TPResult Parser::TryParseFunctionDeclarator() {
1856 // The '(' is already parsed.
1858 TPResult TPR = TryParseParameterDeclarationClause();
1859 if (TPR == TPResult::Ambiguous && Tok.isNot(tok::r_paren))
1860 TPR = TPResult::False;
1862 if (TPR == TPResult::False || TPR == TPResult::Error)
1865 // Parse through the parens.
1866 if (!SkipUntil(tok::r_paren, StopAtSemi))
1867 return TPResult::Error;
1870 while (Tok.isOneOf(tok::kw_const, tok::kw_volatile, tok::kw_restrict))
1873 // ref-qualifier[opt]
1874 if (Tok.isOneOf(tok::amp, tok::ampamp))
1877 // exception-specification
1878 if (Tok.is(tok::kw_throw)) {
1880 if (Tok.isNot(tok::l_paren))
1881 return TPResult::Error;
1883 // Parse through the parens after 'throw'.
1885 if (!SkipUntil(tok::r_paren, StopAtSemi))
1886 return TPResult::Error;
1888 if (Tok.is(tok::kw_noexcept)) {
1890 // Possibly an expression as well.
1891 if (Tok.is(tok::l_paren)) {
1892 // Find the matching rparen.
1894 if (!SkipUntil(tok::r_paren, StopAtSemi))
1895 return TPResult::Error;
1899 return TPResult::Ambiguous;
1902 /// '[' constant-expression[opt] ']'
1904 Parser::TPResult Parser::TryParseBracketDeclarator() {
1906 if (!SkipUntil(tok::r_square, StopAtSemi))
1907 return TPResult::Error;
1909 return TPResult::Ambiguous;