Author: hubert.reinterpretcast Date: Fri May 19 19:21:55 2017 New Revision: 303472
URL: http://llvm.org/viewvc/llvm-project?rev=303472&view=rev Log: Fix valid-for-expr ellipses eaten as invalid decl Summary: The trial parse for declarative syntax accepts an invalid pack declaration syntax, which is ambiguous with valid pack expansions of expressions. This commit removes the invalid pack declaration syntax to avoid mistaking valid pack expansions as invalid declarator components. Additionally, the trial parse of a //template-argument-list// then needs to handle the optional ellipsis that is part of that grammar, as opposed to relying on the trial parse for declarators accepting stray ellipses. Reviewers: rsmith, rcraik, aaron.ballman Reviewed By: rsmith Subscribers: cfe-commits Differential Revision: https://reviews.llvm.org/D33339 Modified: cfe/trunk/lib/Parse/ParseTentative.cpp cfe/trunk/test/Parser/cxx0x-ambig.cpp Modified: cfe/trunk/lib/Parse/ParseTentative.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/ParseTentative.cpp?rev=303472&r1=303471&r2=303472&view=diff ============================================================================== --- cfe/trunk/lib/Parse/ParseTentative.cpp (original) +++ cfe/trunk/lib/Parse/ParseTentative.cpp Fri May 19 19:21:55 2017 @@ -481,10 +481,10 @@ Parser::isCXXConditionDeclarationOrInitS /// the corresponding ')'. If the context is /// TypeIdAsTemplateArgument, we've already parsed the '<' or ',' /// before this template argument, and will cease lookahead when we - /// hit a '>', '>>' (in C++0x), or ','. Returns true for a type-id - /// and false for an expression. If during the disambiguation - /// process a parsing error is encountered, the function returns - /// true to let the declaration parsing code handle it. + /// 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] @@ -533,10 +533,15 @@ bool Parser::isCXXTypeId(TentativeCXXTyp // We are supposed to be inside a template argument, so if after // the abstract declarator we encounter a '>', '>>' (in C++0x), or - // ',', this is a type-id. Otherwise, it's an expression. + // ','; 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.is(tok::greatergreater)))) { + (getLangOpts().CPlusPlus11 && + (Tok.is(tok::greatergreater) || + (Tok.is(tok::ellipsis) && + NextToken().isOneOf(tok::greater, tok::greatergreater, + tok::comma)))))) { TPR = TPResult::True; isAmbiguous = true; @@ -829,14 +834,14 @@ Parser::TPResult Parser::TryParseOperato /// abstract-declarator: /// ptr-operator abstract-declarator[opt] /// direct-abstract-declarator -/// ... /// /// direct-abstract-declarator: /// direct-abstract-declarator[opt] -/// '(' parameter-declaration-clause ')' cv-qualifier-seq[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] @@ -928,10 +933,6 @@ Parser::TPResult Parser::TryParseDeclara while (1) { TPResult TPR(TPResult::Ambiguous); - // abstract-declarator: ... - if (Tok.is(tok::ellipsis)) - ConsumeToken(); - 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 Modified: cfe/trunk/test/Parser/cxx0x-ambig.cpp URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Parser/cxx0x-ambig.cpp?rev=303472&r1=303471&r2=303472&view=diff ============================================================================== --- cfe/trunk/test/Parser/cxx0x-ambig.cpp (original) +++ cfe/trunk/test/Parser/cxx0x-ambig.cpp Fri May 19 19:21:55 2017 @@ -132,6 +132,32 @@ namespace ellipsis { void l(int(*...)(T)); // expected-warning {{ISO C++11 requires a parenthesized pack declaration to have a name}} void l(int(S<int>::*...)(T)); // expected-warning {{ISO C++11 requires a parenthesized pack declaration to have a name}} }; + + struct CtorSink { + template <typename ...T> constexpr CtorSink(T &&...t) { } + constexpr operator int() const { return 42; } + }; + + template <unsigned ...N> struct UnsignedTmplArgSink; + + template <typename ...T> + void foo(int x, T ...t) { + // Have a variety of cases where the syntax is technically unambiguous, but hinges on careful treatment of ellipses. + CtorSink(t ...), x; // ok, expression; expected-warning 2{{expression result unused}} + + int x0(CtorSink(t ...)); // ok, declares object x0 + int *p0 = &x0; + (void)p0; + + CtorSink x1(int(t) ..., int(x)); // ok, declares object x1 + CtorSink *p1 = &x1; + (void)p1; + + UnsignedTmplArgSink<T(CtorSink(t ...)) ...> *t0; // ok + UnsignedTmplArgSink<((T *)0, 42u) ...> **t0p = &t0; + } + + template void foo(int, int, int); // expected-note {{in instantiation of function template specialization 'ellipsis::foo<int, int>' requested here}} } namespace braced_init_list { _______________________________________________ cfe-commits mailing list cfe-commits@lists.llvm.org http://lists.llvm.org/cgi-bin/mailman/listinfo/cfe-commits
