1 files changed, 94 insertions, 0 deletions
diff --git a/lib/StaticAnalyzer/Checkers/UndefinedAssignmentChecker.cpp b/lib/StaticAnalyzer/Checkers/UndefinedAssignmentChecker.cpp
new file mode 100644
index 0000000..e53cbba
--- /dev/null
+++ b/lib/StaticAnalyzer/Checkers/UndefinedAssignmentChecker.cpp
@@ -0,0 +1,94 @@
+//===--- UndefinedAssignmentChecker.h ---------------------------*- C++ -*--==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This defines UndefinedAssginmentChecker, a builtin check in ExprEngine that
+// checks for assigning undefined values.
+//
+//===----------------------------------------------------------------------===//
+
+#include "InternalChecks.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerVisitor.h"
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+class UndefinedAssignmentChecker
+  : public CheckerVisitor<UndefinedAssignmentChecker> {
+  BugType *BT;
+public:
+  UndefinedAssignmentChecker() : BT(0) {}
+  static void *getTag();
+  virtual void PreVisitBind(CheckerContext &C, const Stmt *StoreE,
+                            SVal location, SVal val);
+};
+}
+
+void ento::RegisterUndefinedAssignmentChecker(ExprEngine &Eng){
+  Eng.registerCheck(new UndefinedAssignmentChecker());
+}
+
+void *UndefinedAssignmentChecker::getTag() {
+  static int x = 0;
+  return &x;
+}
+
+void UndefinedAssignmentChecker::PreVisitBind(CheckerContext &C,
+                                              const Stmt *StoreE,
+                                              SVal location,
+                                              SVal val) {
+  if (!val.isUndef())
+    return;
+
+  ExplodedNode *N = C.generateSink();
+
+  if (!N)
+    return;
+
+  const char *str = "Assigned value is garbage or undefined";
+
+  if (!BT)
+    BT = new BuiltinBug(str);
+
+  // Generate a report for this bug.
+  const Expr *ex = 0;
+
+  while (StoreE) {
+    if (const BinaryOperator *B = dyn_cast<BinaryOperator>(StoreE)) {
+      if (B->isCompoundAssignmentOp()) {
+        const GRState *state = C.getState();
+        if (state->getSVal(B->getLHS()).isUndef()) {
+          str = "The left expression of the compound assignment is an "
+                "uninitialized value. The computed value will also be garbage";
+          ex = B->getLHS();
+          break;
+        }
+      }
+
+      ex = B->getRHS();
+      break;
+    }
+
+    if (const DeclStmt *DS = dyn_cast<DeclStmt>(StoreE)) {
+      const VarDecl* VD = dyn_cast<VarDecl>(DS->getSingleDecl());
+      ex = VD->getInit();
+    }
+
+    break;
+  }
+
+  EnhancedBugReport *R = new EnhancedBugReport(*BT, str, N);
+  if (ex) {
+    R->addRange(ex->getSourceRange());
+    R->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, ex);
+  }
+  C.EmitReport(R);
+}
+