[analyzer] Mark symbol values as dead in the environment.

This allows us to properly remove dead bindings at the end of the top-level
stack frame, using the ReturnStmt, if there is one, to keep the return value
live. This in turn removes the need for a check::EndPath callback in leak
checkers.

This does cause some changes in the path notes for leak checkers. Previously,
a leak would be reported at the location of the closing brace in a function.
Now, it gets reported at the last statement. This matches the way leaks are
currently reported for inlined functions, but is less than ideal for both.

llvm-svn: 168066

1 files changed, 5 insertions, 0 deletions

diff --git a/clang/test/Analysis/malloc.c b/clang/test/Analysis/malloc.c
index b939ac36d1a..76dd3a8fda3 100644
--- a/clang/test/Analysis/malloc.c
+++ b/clang/test/Analysis/malloc.c
@@ -1030,6 +1030,11 @@ void *test(void *ptr) {
   return newPtr;
 }
 
+
+char *testLeakWithinReturn(char *str) {
+  return strdup(strdup(str)); // expected-warning{{leak}}
+}
+
 // ----------------------------------------------------------------------------
 // False negatives.