[analyzer] MacOSKeychainAPIChecker: Retrieve the memory region which …

…we are tracking even when it's no longer a SymbolicRegion, for example, when it is cast to char*.

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@138415 91177308-0d34-0410-b5e6-96231b3b80d8

lib/StaticAnalyzer/Checkers/MacOSKeychainAPIChecker.cpp

@@ -167,8 +167,14 @@ unsigned MacOSKeychainAPIChecker::getTrackedFunctionIndex(StringRef Name,
 
 static SymbolRef getSymbolForRegion(CheckerContext &C,
                                    const MemRegion *R) {
-  if (!isa<SymbolicRegion>(R))
-    return 0;
+  if (!isa<SymbolicRegion>(R)) {
+    // Implicit casts (ex: void* -> char*) can turn Symbolic region into element
+    // region, if that is the case, get the underlining region.
+    if (const ElementRegion *ER = dyn_cast<ElementRegion>(R))
+      R = ER->getAsArrayOffset().getRegion();
+    else
+      return 0;
+  }
   return cast<SymbolicRegion>(R)->getSymbol();
 }