[analyzer] If we call a C++ method on an object, assume it's non-null.

This is analogous to our handling of pointer dereferences: if we
dereference a pointer that may or may not be null, we assume it's non-null
from then on.

While some implementations of C++ (including ours) allow you to call a
non-virtual method through a null pointer of object type, it is technically
disallowed by the C++ standard, and should not prune out any real paths in
practice.

  [class.mfct.non-static]p1: A non-static member function may be called
    for an object of its class type, or for an object of a class derived
    from its class type...
  (a null pointer value does not refer to an object)

We can also make the same assumption about function pointers.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@161992 91177308-0d34-0410-b5e6-96231b3b80d8
diff --git a/test/Analysis/func.c b/test/Analysis/func.c
index b6cebde..709ebf7 100644
--- a/test/Analysis/func.c
+++ b/test/Analysis/func.c
@@ -1,4 +1,6 @@
-// RUN: %clang_cc1 -analyze -analyzer-checker=core,experimental.core -analyzer-store=region -verify %s
+// RUN: %clang_cc1 -analyze -analyzer-checker=core,experimental.core,debug.ExprInspection -analyzer-store=region -verify %s
+
+void clang_analyzer_eval(int);
 
 void f(void) {
   void (*p)(void);
@@ -13,3 +15,13 @@
 void f2() {
   g(f);
 }
+
+void f3(void (*f)(void), void (*g)(void)) {
+  clang_analyzer_eval(!f); // expected-warning{{UNKNOWN}}
+  f();
+  clang_analyzer_eval(!f); // expected-warning{{FALSE}}
+
+  clang_analyzer_eval(!g); // expected-warning{{UNKNOWN}}
+  (*g)();
+  clang_analyzer_eval(!g); // expected-warning{{FALSE}}
+}