[analyzer] Let TK_PreserveContents span across the whole base region.

If an address of a field is passed through a const pointer,
the whole structure's base region should receive the
TK_PreserveContents trait and avoid invalidation.

Additionally, include a few FIXME tests shown up during testing.

Differential Revision: http://reviews.llvm.org/D19057

llvm-svn: 267413

1 files changed, 19 insertions, 0 deletions

diff --git a/clang/test/Analysis/malloc.c b/clang/test/Analysis/malloc.c
index 30d72691956..51e2cd60432 100644
--- a/clang/test/Analysis/malloc.c
+++ b/clang/test/Analysis/malloc.c
@@ -1750,6 +1750,19 @@ void testEscapeThroughSystemCallTakingVoidPointer3(fake_rb_tree_t *rbt) {
   fake_rb_tree_insert_node(rbt, data); // no warning
 }
 
+struct IntAndPtr {
+  int x;
+  int *p;
+};
+
+void constEscape(const void *ptr);
+
+void testConstEscapeThroughAnotherField() {
+  struct IntAndPtr s;
+  s.p = malloc(sizeof(int));
+  constEscape(&(s.x)); // could free s->p!
+} // no-warning
+
 // ----------------------------------------------------------------------------
 // False negatives.
 
@@ -1769,3 +1782,9 @@ void testPassToSystemHeaderFunctionIndirectly() {
   // FIXME: This is a leak: if we think a system function won't free p, it
   // won't free (p-1) either.
 }
+
+void testMallocIntoMalloc() {
+  StructWithPtr *s = malloc(sizeof(StructWithPtr));
+  s->memP = malloc(sizeof(int));
+  free(s);
+} // FIXME: should warn here