[Codegen] Don't crash if destructor is not accessible.

Testcase provided, in the PR, by Christian Shelton and
reduced by David Majnemer.

PR:		23584
Differential Revision:	http://reviews.llvm.org/D10508
Reviewed by:	rnk

llvm-svn: 240242
diff --git a/clang/lib/CodeGen/CGClass.cpp b/clang/lib/CodeGen/CGClass.cpp
index 1d2b787..4d6a4e2 100644
--- a/clang/lib/CodeGen/CGClass.cpp
+++ b/clang/lib/CodeGen/CGClass.cpp
@@ -1297,6 +1297,10 @@
   if (BaseClassDecl->hasTrivialDestructor())
     return true;
 
+  // Give up if the destructor is not accessible.
+  if (!BaseClassDecl->getDestructor())
+    return false;
+
   if (!BaseClassDecl->getDestructor()->hasTrivialBody())
     return false;