[analyzer] Allow undefined values in performTrivialCopy.

Reading from a garbage pointer should be modeled as garbage,
and performTrivialCopy should be able to deal with any SVal input.

Patch by Ilya Palachev!

Differential Revision: https://reviews.llvm.org/D25727

llvm-svn: 285640

1 files changed, 34 insertions, 0 deletions

diff --git a/clang/test/Analysis/uninit-vals.cpp b/clang/test/Analysis/uninit-vals.cpp
new file mode 100644
index 00000000000..387c3754dae
--- /dev/null
+++ b/clang/test/Analysis/uninit-vals.cpp
@@ -0,0 +1,34 @@
+// RUN: %clang_cc1 -analyze -analyzer-checker=core.builtin -verify -DCHECK_FOR_CRASH %s
+// RUN: %clang_cc1 -analyze -analyzer-checker=core -verify %s
+
+#ifdef CHECK_FOR_CRASH
+// expected-no-diagnostics
+#endif
+
+namespace PerformTrivialCopyForUndefs {
+struct A {
+  int x;
+};
+
+struct B {
+  A a;
+};
+
+struct C {
+  B b;
+};
+
+void foo() {
+  C c1;
+  C *c2;
+#ifdef CHECK_FOR_CRASH
+  // If the value of variable is not defined and checkers that check undefined
+  // values are not enabled, performTrivialCopy should be able to handle the
+  // case with undefined values, too.
+  c1.b.a = c2->b.a;
+#else
+  c1.b.a = c2->b.a; // expected-warning{{Function call argument is an uninitialized value}}
+#endif
+}
+}
+