Don't crash when passing &@selector to a _Nonnull parameter. Fixes PR24774.

The root cause here is that ObjCSelectorExpr is an rvalue, yet it can have its
address taken.  That's kind of awkward, but fixing this is awkward in other
ways, see https://llvm.org/bugs/show_bug.cgi?id=24774#c16 .  For now, just
fix the crash.

llvm-svn: 247740

2 files changed, 9 insertions, 3 deletions

diff --git a/clang/lib/AST/ExprConstant.cpp b/clang/lib/AST/ExprConstant.cpp
index 5eaf40eb2ad..2fb8c9c137b 100644
--- a/clang/lib/AST/ExprConstant.cpp
+++ b/clang/lib/AST/ExprConstant.cpp
@@ -4557,12 +4557,13 @@ public:
 } // end anonymous namespace
 
 /// Evaluate an expression as an lvalue. This can be legitimately called on
-/// expressions which are not glvalues, in two cases:
+/// expressions which are not glvalues, in three cases:
 ///  * function designators in C, and
 ///  * "extern void" objects
+///  * @selector() expressions in Objective-C
 static bool EvaluateLValue(const Expr *E, LValue &Result, EvalInfo &Info) {
   assert(E->isGLValue() || E->getType()->isFunctionType() ||
-         E->getType()->isVoidType());
+         E->getType()->isVoidType() || isa<ObjCSelectorExpr>(E));
   return LValueExprEvaluator(Info, Result).Visit(E);
 }
 
diff --git a/clang/test/SemaObjCXX/sel-address.mm b/clang/test/SemaObjCXX/sel-address.mm
index 931d793fd50..a1209abd4e6 100644
--- a/clang/test/SemaObjCXX/sel-address.mm
+++ b/clang/test/SemaObjCXX/sel-address.mm
@@ -2,7 +2,8 @@
 // pr7390
 
 void f(const SEL& v2) {}
-void g() {
+void g(SEL* _Nonnull);
+void h() {
   f(@selector(dealloc));
 
   SEL s = @selector(dealloc);
@@ -11,4 +12,8 @@ void g() {
   @selector(dealloc) = s;  // expected-error {{expression is not assignable}}
 
   SEL* ps2 = &@selector(dealloc);
+
+  // Shouldn't crash.
+  g(&@selector(foo));
 }
+