[analyzer] Ensure that loop widening does not invalidate references

Loop widening can invalidate a reference. If the analyzer attempts to visit the
destructor to a non-existent reference, it will crash. This patch ensures that
the reference is preserved.

https://reviews.llvm.org/D47044



git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@334554 91177308-0d34-0410-b5e6-96231b3b80d8

1 files changed, 14 insertions, 0 deletions

diff --git a/test/Analysis/loop-widening-preserve-reference-type.cpp b/test/Analysis/loop-widening-preserve-reference-type.cpp
new file mode 100644
index 0000000000..b5746d1fe7
--- /dev/null
+++ b/test/Analysis/loop-widening-preserve-reference-type.cpp
@@ -0,0 +1,14 @@
+// RUN: %clang_analyze_cc1 -analyzer-checker=core,unix.Malloc,debug.ExprInspection -analyzer-max-loop 4 -analyzer-config widen-loops=true -verify %s
+
+void clang_analyzer_eval(int);
+
+struct A {
+  ~A() {}
+};
+struct B : public A {};
+
+void invalid_type_region_access() {
+  const A &x = B();
+  for (int i = 0; i < 10; ++i) { }
+  clang_analyzer_eval(&x != 0); // expected-warning{{TRUE}}
+}                               // expected-warning@-1{{reference cannot be bound to dereferenced null pointer in well-defined C++ code; comparison may be assumed to always evaluate to true}}