[analyzer] Ensure BugReporterTracking works on regions with pointer arithmetic

Introduce a new helper function, which computes the first symbolic region in
the base region chain. The corresponding symbol has been used for assuming that
a pointer is null. Now, it will also be used for checking if it is null.

This ensures that we are tracking a null pointer correctly in the BugReporter.

llvm-svn: 179916

1 files changed, 13 insertions, 0 deletions

diff --git a/clang/test/Analysis/inlining/inline-defensive-checks.c b/clang/test/Analysis/inlining/inline-defensive-checks.c
index df3a8f22811..aa7f70030c0 100644
--- a/clang/test/Analysis/inlining/inline-defensive-checks.c
+++ b/clang/test/Analysis/inlining/inline-defensive-checks.c
@@ -97,3 +97,16 @@ void test24(char *buffer) {
   use(buffer);
   buffer[1] = 'b';
 }
+
+// Ensure idc works on pointers with constant offset.
+void idcchar(const char *s2) {
+  if(s2)
+    ;
+}
+void testConstantOffset(char *value) {
+  char *cursor = value + 5;
+  idcchar(cursor);
+  if (*cursor) {
+    cursor++;
+  }
+}