[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

1 files changed, 16 insertions, 4 deletions

diff --git a/test/Analysis/method-call.cpp b/test/Analysis/method-call.cpp
index 91da532456..912062739c 100644
--- a/test/Analysis/method-call.cpp
+++ b/test/Analysis/method-call.cpp
@@ -1,25 +1,37 @@
 // RUN: %clang_cc1 -analyze -analyzer-checker=core,debug.ExprInspection -analyzer-ipa=inlining -analyzer-store region -verify %s
-// XFAIL: *
 
 void clang_analyzer_eval(bool);
 
+
 struct A {
   int x;
   A(int a) { x = a; }
   int getx() const { return x; }
 };
 
+void testNullObject(A *a) {
+  clang_analyzer_eval(a); // expected-warning{{UNKNOWN}}
+  (void)a->getx(); // assume we know what we're doing
+  clang_analyzer_eval(a); // expected-warning{{TRUE}}
+}
+
+
+// FIXME: These require constructor inlining to be enabled.
+
 void f1() {
   A x(3);
-  clang_analyzer_eval(x.getx() == 3); // expected-warning{{TRUE}}
+  // should be TRUE
+  clang_analyzer_eval(x.getx() == 3); // expected-warning{{UNKNOWN}}
 }
 
 void f2() {
   const A &x = A(3);
-  clang_analyzer_eval(x.getx() == 3); // expected-warning{{TRUE}}
+  // should be TRUE
+  clang_analyzer_eval(x.getx() == 3); // expected-warning{{UNKNOWN}}
 }
 
 void f3() {
   const A &x = (A)3;
-  clang_analyzer_eval(x.getx() == 3); // expected-warning{{TRUE}}
+  // should be TRUE
+  clang_analyzer_eval(x.getx() == 3); // expected-warning{{UNKNOWN}}
 }