[analyzer][MallocChecker] Fix the incorrect retrieval of the from argument in realloc()

In the added testfile, the from argument was recognized as
&Element{SymRegion{reg_$0<long * global_a>},-1 S64b,long}
instead of
reg_$0<long * global_a>.

2 files changed, 8 insertions, 1 deletions

diff --git a/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp b/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
index fa69bc2..fb6d02b 100644
--- a/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
+++ b/clang/lib/StaticAnalyzer/Checkers/MallocChecker.cpp
@@ -2470,7 +2470,7 @@ MallocChecker::ReallocMemAux(CheckerContext &C, const CallEvent &Call,
       Kind = OAR_DoNotTrackAfterFailure;
 
     // Get the from and to pointer symbols as in toPtr = realloc(fromPtr, size).
-    SymbolRef FromPtr = arg0Val.getAsSymbol();
+    SymbolRef FromPtr = arg0Val.getLocSymbolInBase();
     SVal RetVal = C.getSVal(CE);
     SymbolRef ToPtr = RetVal.getAsSymbol();
     assert(FromPtr && ToPtr &&
diff --git a/clang/test/Analysis/malloc.c b/clang/test/Analysis/malloc.c
index a8aabf9..714c73c3 100644
--- a/clang/test/Analysis/malloc.c
+++ b/clang/test/Analysis/malloc.c
@@ -1848,6 +1848,13 @@ variable 'buf', which is not memory allocated by malloc() [unix.Malloc]}}
 crash_b() { crash_a(); } // no-crash
 // expected-warning@-1{{type specifier missing}} expected-warning@-1{{non-void}}
 
+long *global_a;
+void realloc_crash() {
+  long *c = global_a;
+  c--;
+  realloc(c, 8); // no-crash
+} // expected-warning{{Potential memory leak [unix.Malloc]}}
+
 // ----------------------------------------------------------------------------
 // False negatives.