[cfe-commits] r169689 - in /cfe/trunk: include/clang/Basic/DiagnosticSemaKinds.td lib/Sema/SemaDeclCXX.cpp test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p5.cpp

[Richard Smith]

Author: rsmith
Date: Sat Dec  8 23:55:43 2012
New Revision: 169689

URL: http://llvm.org/viewvc/llvm-project?rev=169689&view=rev
Log:
PR14550: If a system header contains a bogus constexpr function definition,
don't mark the function as invalid, since we suppress the error.

Modified:
    cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
    cfe/trunk/lib/Sema/SemaDeclCXX.cpp
    cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p5.cpp

Modified: cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td?rev=169689&r1=169688&r2=169689&view=diff
==============================================================================
--- cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td (original)
+++ cfe/trunk/include/clang/Basic/DiagnosticSemaKinds.td Sat Dec  8 23:55:43 2012
@@ -1538,7 +1538,7 @@
   "%select{function|constructor}1">;
 def err_constexpr_var_declaration : Error<
   "variables cannot be declared in a constexpr %select{function|constructor}0">;
-def err_constexpr_function_never_constant_expr : ExtWarn<
+def ext_constexpr_function_never_constant_expr : ExtWarn<
   "constexpr %select{function|constructor}0 never produces a "
   "constant expression">, InGroup<DiagGroup<"invalid-constexpr">>, DefaultError;
 def err_constexpr_body_no_return : Error<

Modified: cfe/trunk/lib/Sema/SemaDeclCXX.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Sema/SemaDeclCXX.cpp?rev=169689&r1=169688&r2=169689&view=diff
==============================================================================
--- cfe/trunk/lib/Sema/SemaDeclCXX.cpp (original)
+++ cfe/trunk/lib/Sema/SemaDeclCXX.cpp Sat Dec  8 23:55:43 2012
@@ -994,11 +994,12 @@
   //     base class sub-objects shall be a constexpr constructor.
   llvm::SmallVector<PartialDiagnosticAt, 8> Diags;
   if (!Expr::isPotentialConstantExpr(Dcl, Diags)) {
-    Diag(Dcl->getLocation(), diag::err_constexpr_function_never_constant_expr)
+    Diag(Dcl->getLocation(), diag::ext_constexpr_function_never_constant_expr)
       << isa<CXXConstructorDecl>(Dcl);
     for (size_t I = 0, N = Diags.size(); I != N; ++I)
       Diag(Diags[I].first, Diags[I].second);
-    return false;
+    // Don't return false here: we allow this for compatibility in
+    // system headers.
   }
 
   return true;

Modified: cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p5.cpp
URL: http://llvm.org/viewvc/llvm-project/cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p5.cpp?rev=169689&r1=169688&r2=169689&view=diff
==============================================================================
--- cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p5.cpp (original)
+++ cfe/trunk/test/CXX/dcl.dcl/dcl.spec/dcl.constexpr/p5.cpp Sat Dec  8 23:55:43 2012
@@ -1,5 +1,5 @@
 // RUN: %clang_cc1 -fsyntax-only -triple x86_64-unknown-unknown -verify -std=c++11 -fcxx-exceptions %s
-// RUN: %clang_cc1 -fsyntax-only -triple x86_64-unknown-unknown -std=c++11 -fcxx-exceptions -Wno-invalid-constexpr %s
+// RUN: %clang_cc1 -fsyntax-only -triple x86_64-unknown-unknown -std=c++11 -fcxx-exceptions -Wno-invalid-constexpr %s -DNO_INVALID_CONSTEXPR
 
 namespace StdExample {
 
@@ -110,3 +110,23 @@
 int y2 = Y<Z>().get(); // ok
 
 }
+
+#ifndef NO_INVALID_CONSTEXPR
+namespace PR14550 {
+  // As an "extension", we allow functions which can't produce constant
+  // expressions to be declared constexpr in system headers (libstdc++
+  // marks some functions as constexpr which use builtins which we don't
+  // support constant folding). Ensure that we don't mark those functions
+  // as invalid after suppressing the diagnostic.
+# 122 "p5.cpp" 1 3
+  int n;
+  struct A {
+    static constexpr int f() { return n; }
+  };
+  template<typename T> struct B {
+    B() { g(T::f()); } // expected-error {{undeclared identifier 'g'}}
+  };
+# 130 "p5.cpp" 2
+  template class B<A>; // expected-note {{here}}
+}
+#endif