[cfe-commits] r150163 - in /cfe/trunk: include/clang/Basic/DiagnosticSemaKinds.td include/clang/Sema/Sema.h lib/Sema/SemaExpr.cpp lib/Sema/SemaLambda.cpp test/CXX/expr/expr.prim/expr.prim.lambda/p2.cpp
Douglas Gregor
dgregor at apple.com
Thu Feb 9 00:14:44 PST 2012
Author: dgregor
Date: Thu Feb 9 02:14:43 2012
New Revision: 150163
URL: http://llvm.org/viewvc/llvm-project?rev=150163&view=rev
Log:
Implement C++ [expr.prim.lambda]p2, which bans lambda expressions in
unevaluated operands. Be certain that we're marking everything
referenced within a capture initializer as odr-used.
Added:
cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p2.cpp (with props)
Modified:
cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
cfe/trunk/include/clang/Sema/Sema.h
cfe/trunk/lib/Sema/SemaExpr.cpp
cfe/trunk/lib/Sema/SemaLambda.cpp
Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=150163&r1=150162&r2=150163&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Thu Feb 9 02:14:43 2012
@@ -4125,7 +4125,8 @@
"variable %0 cannot be implicitly captured in a lambda with no "
"capture-default specified">;
def note_lambda_decl : Note<"lambda expression begins here">;
-
+def err_lambda_unevaluated_operand : Error<
+ "lambda expression in an unevaluated operand">;
def err_operator_arrow_circular : Error<
"circular pointer delegation detected">;
Modified: cfe/trunk/include/clang/Sema/Sema.h
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Sema/Sema.h?rev=150163&r1=150162&r2=150163&view=diff
==============================================================================
--- cfe/trunk/include/clang/Sema/Sema.h (original)
+++ cfe/trunk/include/clang/Sema/Sema.h Thu Feb 9 02:14:43 2012
@@ -102,6 +102,7 @@
class InitializedEntity;
class IntegerLiteral;
class LabelStmt;
+ class LambdaExpr;
class LangOptions;
class LocalInstantiationScope;
class LookupResult;
@@ -560,6 +561,10 @@
llvm::SmallPtrSet<Expr*, 8> SavedMaybeODRUseExprs;
+ /// \brief The lambdas that are present within this context, if it
+ /// is indeed an unevaluated context.
+ llvm::SmallVector<LambdaExpr *, 2> Lambdas;
+
ExpressionEvaluationContextRecord(ExpressionEvaluationContext Context,
unsigned NumCleanupObjects,
bool ParentNeedsCleanups)
Modified: cfe/trunk/lib/Sema/SemaExpr.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaExpr.cpp?rev=150163&r1=150162&r2=150163&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaExpr.cpp (original)
+++ cfe/trunk/lib/Sema/SemaExpr.cpp Thu Feb 9 02:14:43 2012
@@ -9282,6 +9282,12 @@
return BaseTransform::TransformUnaryOperator(E);
}
+ /// \brief Transform the capture expressions in the lambda
+ /// expression.
+ ExprResult TransformLambdaExpr(LambdaExpr *E) {
+ // Lambdas never need to be transformed.
+ return E;
+ }
};
}
@@ -9307,6 +9313,29 @@
void Sema::PopExpressionEvaluationContext() {
ExpressionEvaluationContextRecord& Rec = ExprEvalContexts.back();
+ if (!Rec.Lambdas.empty()) {
+ if (Rec.Context == Unevaluated) {
+ // C++11 [expr.prim.lambda]p2:
+ // A lambda-expression shall not appear in an unevaluated operand
+ // (Clause 5).
+ for (unsigned I = 0, N = Rec.Lambdas.size(); I != N; ++I)
+ Diag(Rec.Lambdas[I]->getLocStart(),
+ diag::err_lambda_unevaluated_operand);
+ } else {
+ // Mark the capture expressions odr-used. This was deferred
+ // during lambda expression creation.
+ for (unsigned I = 0, N = Rec.Lambdas.size(); I != N; ++I) {
+ LambdaExpr *Lambda = Rec.Lambdas[I];
+ for (LambdaExpr::capture_init_iterator
+ C = Lambda->capture_init_begin(),
+ CEnd = Lambda->capture_init_end();
+ C != CEnd; ++C) {
+ MarkDeclarationsReferencedInExpr(*C);
+ }
+ }
+ }
+ }
+
// When are coming out of an unevaluated context, clear out any
// temporaries that we may have created as part of the evaluation of
// the expression in that context: they aren't relevant because they
@@ -9318,6 +9347,8 @@
CleanupVarDeclMarking();
std::swap(MaybeODRUseExprs, Rec.SavedMaybeODRUseExprs);
+ if (Rec.Context == Unevaluated) {
+ }
// Otherwise, merge the contexts together.
} else {
ExprNeedsCleanups |= Rec.ParentNeedsCleanups;
@@ -9589,8 +9620,9 @@
//
// FIXME: Introduce an initialization entity for lambda captures.
- // Introduce a new evaluation context for the initialization, so that
- // temporaries introduced as part of the capture
+ // Introduce a new evaluation context for the initialization, so
+ // that temporaries introduced as part of the capture are retained
+ // to be re-"exported" from the lambda expression itself.
S.PushExpressionEvaluationContext(Sema::PotentiallyEvaluated);
Expr *Ref = new (S.Context) DeclRefExpr(Var, Type.getNonReferenceType(),
Modified: cfe/trunk/lib/Sema/SemaLambda.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaLambda.cpp?rev=150163&r1=150162&r2=150163&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaLambda.cpp (original)
+++ cfe/trunk/lib/Sema/SemaLambda.cpp Thu Feb 9 02:14:43 2012
@@ -357,9 +357,28 @@
if (LambdaExprNeedsCleanups)
ExprNeedsCleanups = true;
- Expr *Lambda = LambdaExpr::Create(Context, Class, IntroducerRange,
- CaptureDefault, Captures, ExplicitParams,
- CaptureInits, Body->getLocEnd());
+ LambdaExpr *Lambda = LambdaExpr::Create(Context, Class, IntroducerRange,
+ CaptureDefault, Captures,
+ ExplicitParams, CaptureInits,
+ Body->getLocEnd());
+
+ // C++11 [expr.prim.lambda]p2:
+ // A lambda-expression shall not appear in an unevaluated operand
+ // (Clause 5).
+ switch (ExprEvalContexts.back().Context) {
+ case Unevaluated:
+ // We don't actually diagnose this case immediately, because we
+ // could be within a context where we might find out later that
+ // the expression is potentially evaluated (e.g., for typeid).
+ ExprEvalContexts.back().Lambdas.push_back(Lambda);
+ break;
+
+ case ConstantEvaluated:
+ case PotentiallyEvaluated:
+ case PotentiallyEvaluatedIfUsed:
+ break;
+ }
+
Diag(StartLoc, diag::err_lambda_unsupported);
return MaybeBindToTemporary(Lambda);
Added: cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p2.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p2.cpp?rev=150163&view=auto
==============================================================================
--- cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p2.cpp (added)
+++ cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p2.cpp Thu Feb 9 02:14:43 2012
@@ -0,0 +1,48 @@
+// RUN: %clang_cc1 -fsyntax-only -std=c++11 %s -verify
+
+// prvalue
+void prvalue() {
+ auto&& x = []()->void { }; // expected-error{{lambda expressions are not supported yet}}
+ auto& y = []()->void { }; // expected-error{{cannot bind to a temporary of type}} \
+ // expected-error{{lambda expressions are not supported yet}}
+}
+
+namespace std {
+ class type_info;
+}
+
+struct P {
+ virtual ~P();
+};
+
+void unevaluated_operand(P &p, int i) {
+ int i2 = sizeof([]()->void{}()); // expected-error{{lambda expression in an unevaluated operand}} \
+ // expected-error{{lambda expressions are not supported yet}}
+ const std::type_info &ti1 = typeid([&]() -> P& { return p; }()); // expected-error{{lambda expressions are not supported yet}}
+ const std::type_info &ti2 = typeid([&]() -> int { return i; }()); // expected-error{{lambda expression in an unevaluated operand}} \
+ // expected-error{{lambda expressions are not supported yet}}
+}
+
+template<typename T>
+struct Boom {
+ Boom(const Boom&) {
+ T* x = 1; // expected-error{{cannot initialize a variable of type 'int *' with an rvalue of type 'int'}} \
+ // expected-error{{cannot initialize a variable of type 'float *' with an rvalue of type 'int'}} \
+ // expected-error{{cannot initialize a variable of type 'double *' with an rvalue of type 'int'}}
+ }
+ void tickle() const;
+};
+
+void odr_used(P &p, Boom<int> boom_int, Boom<float> boom_float,
+ Boom<double> boom_double) {
+ const std::type_info &ti1
+ = typeid([=,&p]() -> P& { boom_int.tickle(); return p; }()); // expected-error{{lambda expressions are not supported yet}} \
+ // expected-note{{in instantiation of member function 'Boom<int>::Boom' requested here}}
+ const std::type_info &ti2
+ = typeid([=]() -> int { boom_float.tickle(); return 0; }()); // expected-error{{lambda expression in an unevaluated operand}} \
+ // expected-error{{lambda expressions are not supported yet}} \
+ // expected-note{{in instantiation of member function 'Boom<float>::Boom' requested here}}
+
+ auto foo = [=]() -> int { boom_double.tickle(); return 0; }; // expected-error{{lambda expressions are not supported yet}} \
+ // expected-note{{in instantiation of member function 'Boom<double>::Boom' requested here}}
+}
Propchange: cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p2.cpp
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Propchange: cfe/trunk/test/CXX/expr/expr.prim/expr.prim.lambda/p2.cpp
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