Prevent Scoped Enums from being Integral constant expressions:

Discovered because of: https://bugs.llvm.org/show_bug.cgi?id=38235

It seems to me that a scoped enum should NOT be an integral constant expression
without a cast, so this seems like a sensical change.

Attributes that check for an integer parameter simply use this function to
ensure that they have an integer, so it was previously allowing a scoped enum.

Also added a test based on Richard's feedback to ensure that case labels still work.

Differential Revision: https://reviews.llvm.org/D49599

llvm-svn: 337585

2 files changed, 15 insertions, 1 deletions

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index bf21bc65e2b..e69914f25da 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -11142,7 +11142,7 @@ static bool EvaluateCPlusPlus11IntegralConstantExpr(const ASTContext &Ctx,
                                                     const Expr *E,
                                                     llvm::APSInt *Value,
                                                     SourceLocation *Loc) {
-  if (!E->getType()->isIntegralOrEnumerationType()) {
+  if (!E->getType()->isIntegralOrUnscopedEnumerationType()) {
     if (Loc) *Loc = E->getExprLoc();
     return false;
   }
diff --git a/clang/test/SemaCXX/PR38235.cpp b/clang/test/SemaCXX/PR38235.cpp
new file mode 100644
index 00000000000..11874c837bc
--- /dev/null
+++ b/clang/test/SemaCXX/PR38235.cpp
@@ -0,0 +1,14 @@
+// RUN: %clang_cc1 -fsyntax-only -verify %s
+
+enum class E { Foo, Bar = 97119 };
+
+void f() __attribute__((constructor(E::Foo))); // expected-error{{'constructor' attribute requires an integer constant}}
+void f2() __attribute__((constructor(E::Bar)));// expected-error{{'constructor' attribute requires an integer constant}}
+
+void switch_me(E e) {
+  switch (e) {
+    case E::Foo:
+    case E::Bar:
+      break;
+  }
+}