[analyzer] Match more patterns in bugreporter::getDerefExpr() API.

This function can now track null pointer through simple pointer arithmetic,
such as '*&*(p + 2)' => 'p' and so on, displaying intermediate diagnostic pieces
for the user to understand where the null pointer is coming from.

Differential Revision: https://reviews.llvm.org/D37025

llvm-svn: 314290

1 files changed, 12 insertions, 0 deletions

diff --git a/clang/test/Analysis/inlining/inline-defensive-checks.c b/clang/test/Analysis/inlining/inline-defensive-checks.c
index 010d3a77475..9f211b502bc 100644
--- a/clang/test/Analysis/inlining/inline-defensive-checks.c
+++ b/clang/test/Analysis/inlining/inline-defensive-checks.c
@@ -169,6 +169,18 @@ void idcTrackZeroValueThroughUnaryPointerOperatorsWithAssignment(struct S *s) {
   *x = 7; // no-warning
 }
 
+void idcTrackZeroValueThroughManyUnaryPointerOperatorsWithAssignment(struct S *s) {
+  idc(s);
+  int *x = &*&(s->f1);
+  *x = 7; // no-warning
+}
+
+void idcTrackZeroValueThroughManyUnaryPointerOperatorsWithAssignmentAndUnaryIncrement(struct S *s) {
+  idc(s);
+  int *x = &*&((++s)->f1);
+  *x = 7; // no-warning
+}
+
 
 struct S2 {
   int a[1];