r240611 - [Concepts] Parsing of requires-clause in template-declaration
Hubert Tong
hubert.reinterpretcast at gmail.com
Wed Jun 24 17:23:39 PDT 2015
Author: hubert.reinterpretcast
Date: Wed Jun 24 19:23:39 2015
New Revision: 240611
URL: http://llvm.org/viewvc/llvm-project?rev=240611&view=rev
Log:
[Concepts] Parsing of requires-clause in template-declaration
Summary:
This change implements parse-only acceptance of the optional
requires-clause in a template-declaration. Diagnostic testing is added
for cases where the grammar is ambiguous with the expectation that the
longest token sequence which matches the syntax of a
constraint-expression is consumed without backtracking.
Reviewers: faisalv, fraggamuffin, rsmith
Reviewed By: rsmith
Subscribers: cfe-commits
Differential Revision: http://reviews.llvm.org/D10462
Added:
cfe/trunk/test/Parser/cxx-concepts-ambig-constraint-expr.cpp
cfe/trunk/test/Parser/cxx-concepts-requires-clause.cpp
Modified:
cfe/trunk/include/clang/Parse/Parser.h
cfe/trunk/lib/Parse/ParseExpr.cpp
cfe/trunk/lib/Parse/ParseTemplate.cpp
Modified: cfe/trunk/include/clang/Parse/Parser.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Parse/Parser.h?rev=240611&r1=240610&r2=240611&view=diff
==============================================================================
--- cfe/trunk/include/clang/Parse/Parser.h (original)
+++ cfe/trunk/include/clang/Parse/Parser.h Wed Jun 24 19:23:39 2015
@@ -1331,6 +1331,7 @@ public:
ExprResult ParseExpression(TypeCastState isTypeCast = NotTypeCast);
ExprResult ParseConstantExpression(TypeCastState isTypeCast = NotTypeCast);
+ ExprResult ParseConstraintExpression();
// Expr that doesn't include commas.
ExprResult ParseAssignmentExpression(TypeCastState isTypeCast = NotTypeCast);
Modified: cfe/trunk/lib/Parse/ParseExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/ParseExpr.cpp?rev=240611&r1=240610&r2=240611&view=diff
==============================================================================
--- cfe/trunk/lib/Parse/ParseExpr.cpp (original)
+++ cfe/trunk/lib/Parse/ParseExpr.cpp Wed Jun 24 19:23:39 2015
@@ -205,6 +205,24 @@ ExprResult Parser::ParseConstantExpressi
return Actions.ActOnConstantExpression(Res);
}
+/// \brief Parse a constraint-expression.
+///
+/// \verbatim
+/// constraint-expression: [Concepts TS temp.constr.decl p1]
+/// logical-or-expression
+/// \endverbatim
+ExprResult Parser::ParseConstraintExpression() {
+ // FIXME: this may erroneously consume a function-body as the braced
+ // initializer list of a compound literal
+ //
+ // FIXME: this may erroneously consume a parenthesized rvalue reference
+ // declarator as a parenthesized address-of-label expression
+ ExprResult LHS(ParseCastExpression(/*isUnaryExpression=*/false));
+ ExprResult Res(ParseRHSOfBinaryExpression(LHS, prec::LogicalOr));
+
+ return Res;
+}
+
bool Parser::isNotExpressionStart() {
tok::TokenKind K = Tok.getKind();
if (K == tok::l_brace || K == tok::r_brace ||
Modified: cfe/trunk/lib/Parse/ParseTemplate.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Parse/ParseTemplate.cpp?rev=240611&r1=240610&r2=240611&view=diff
==============================================================================
--- cfe/trunk/lib/Parse/ParseTemplate.cpp (original)
+++ cfe/trunk/lib/Parse/ParseTemplate.cpp Wed Jun 24 19:23:39 2015
@@ -116,7 +116,7 @@ Parser::ParseTemplateDeclarationOrSpecia
SmallVector<Decl*, 4> TemplateParams;
if (ParseTemplateParameters(CurTemplateDepthTracker.getDepth(),
TemplateParams, LAngleLoc, RAngleLoc)) {
- // Skip until the semi-colon or a }.
+ // Skip until the semi-colon or a '}'.
SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch);
TryConsumeToken(tok::semi);
return nullptr;
@@ -132,6 +132,17 @@ Parser::ParseTemplateDeclarationOrSpecia
if (!TemplateParams.empty()) {
isSpecialization = false;
++CurTemplateDepthTracker;
+
+ if (TryConsumeToken(tok::kw_requires)) {
+ ExprResult ER =
+ Actions.CorrectDelayedTyposInExpr(ParseConstraintExpression());
+ if (!ER.isUsable()) {
+ // Skip until the semi-colon or a '}'.
+ SkipUntil(tok::r_brace, StopAtSemi | StopBeforeMatch);
+ TryConsumeToken(tok::semi);
+ return nullptr;
+ }
+ }
} else {
LastParamListWasEmpty = true;
}
Added: cfe/trunk/test/Parser/cxx-concepts-ambig-constraint-expr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Parser/cxx-concepts-ambig-constraint-expr.cpp?rev=240611&view=auto
==============================================================================
--- cfe/trunk/test/Parser/cxx-concepts-ambig-constraint-expr.cpp (added)
+++ cfe/trunk/test/Parser/cxx-concepts-ambig-constraint-expr.cpp Wed Jun 24 19:23:39 2015
@@ -0,0 +1,29 @@
+// RUN: %clang_cc1 -std=c++14 -fconcepts-ts -x c++ %s -verify
+
+// Test parsing of constraint-expressions in cases where the grammar is
+// ambiguous with the expectation that the longest token sequence which matches
+// the syntax is consumed without backtracking.
+
+// type-specifier-seq in conversion-type-id
+template <typename T> requires (bool)&T::operator short
+unsigned int foo(); // expected-error {{C++ requires a type specifier for all declarations}}
+
+// type-specifier-seq in new-type-id
+template <typename T> requires (bool)sizeof new (T::f()) short
+unsigned int bar(); // expected-error {{C++ requires a type specifier for all declarations}}
+
+template<typename T> requires (bool)sizeof new (T::f()) unsigned // expected-error {{'struct' cannot be signed or unsigned}}
+struct X { }; // expected-error {{'X' cannot be defined in a type specifier}}
+
+// C-style cast
+// of function call on function-style cast
+template <typename T> requires (bool(T()))
+T (*fp)(); // expected-error {{use of undeclared identifier 'fp'}}
+
+// function-style cast
+// as the callee in a function call
+struct A {
+ static int t;
+ template <typename T> requires bool(T())
+ (A(T (&t))) { } // expected-error {{called object type 'bool' is not a function or function pointer}}
+};
Added: cfe/trunk/test/Parser/cxx-concepts-requires-clause.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Parser/cxx-concepts-requires-clause.cpp?rev=240611&view=auto
==============================================================================
--- cfe/trunk/test/Parser/cxx-concepts-requires-clause.cpp (added)
+++ cfe/trunk/test/Parser/cxx-concepts-requires-clause.cpp Wed Jun 24 19:23:39 2015
@@ -0,0 +1,82 @@
+// RUN: %clang_cc1 -std=c++14 -fconcepts-ts -x c++ %s -verify
+// expected-no-diagnostics
+
+// Test parsing of the optional requires-clause in a template-declaration.
+
+template <typename T> requires true
+void foo() { }
+
+
+template <typename T> requires !0
+struct A {
+ void foo();
+ struct AA;
+ enum E : int;
+ static int x;
+
+ template <typename> requires true
+ void Mfoo();
+
+ template <typename> requires true
+ struct M;
+
+ template <typename> requires true
+ static int Mx;
+
+ template <typename TT> requires true
+ using MQ = M<TT>;
+};
+
+template <typename T> requires !0
+void A<T>::foo() { }
+
+template <typename T> requires !0
+struct A<T>::AA { };
+
+template <typename T> requires !0
+enum A<T>::E : int { E0 };
+
+template <typename T> requires !0
+int A<T>::x = 0;
+
+template <typename T> requires !0
+template <typename> requires true
+void A<T>::Mfoo() { }
+
+template <typename T> requires !0
+template <typename> requires true
+struct A<T>::M { };
+
+template <typename T> requires !0
+template <typename> requires true
+int A<T>::Mx = 0;
+
+
+template <typename T> requires true
+int x = 0;
+
+template <typename T> requires true
+using Q = A<T>;
+
+struct C {
+ template <typename> requires true
+ void Mfoo();
+
+ template <typename> requires true
+ struct M;
+
+ template <typename> requires true
+ static int Mx;
+
+ template <typename T> requires true
+ using MQ = M<T>;
+};
+
+template <typename> requires true
+void C::Mfoo() { }
+
+template <typename> requires true
+struct C::M { };
+
+template <typename> requires true
+int C::Mx = 0;
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