1 files changed, 91 insertions, 0 deletions
diff --git a/lib/Checker/ArrayBoundChecker.cpp b/lib/Checker/ArrayBoundChecker.cpp
new file mode 100644
index 0000000..74fb06f
--- /dev/null
+++ b/lib/Checker/ArrayBoundChecker.cpp
@@ -0,0 +1,91 @@
+//== ArrayBoundChecker.cpp ------------------------------*- C++ -*--==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines ArrayBoundChecker, which is a path-sensitive check
+// which looks for an out-of-bound array element access.
+//
+//===----------------------------------------------------------------------===//
+
+#include "GRExprEngineInternalChecks.h"
+#include "clang/Checker/PathSensitive/GRExprEngine.h"
+#include "clang/Checker/BugReporter/BugReporter.h"
+#include "clang/Checker/PathSensitive/CheckerVisitor.h"
+
+using namespace clang;
+
+namespace {
+class ArrayBoundChecker : 
+    public CheckerVisitor<ArrayBoundChecker> {      
+  BuiltinBug *BT;
+public:
+    ArrayBoundChecker() : BT(0) {}
+    static void *getTag();
+    void VisitLocation(CheckerContext &C, const Stmt *S, SVal l);
+};
+}
+
+void clang::RegisterArrayBoundChecker(GRExprEngine &Eng) {
+  Eng.registerCheck(new ArrayBoundChecker());
+}
+
+void *ArrayBoundChecker::getTag() {
+  static int x = 0; return &x;
+}
+
+void ArrayBoundChecker::VisitLocation(CheckerContext &C, const Stmt *S, SVal l){
+  // Check for out of bound array element access.
+  const MemRegion *R = l.getAsRegion();
+  if (!R)
+    return;
+
+  R = R->StripCasts();
+
+  const ElementRegion *ER = dyn_cast<ElementRegion>(R);
+  if (!ER)
+    return;
+
+  // Get the index of the accessed element.
+  DefinedOrUnknownSVal &Idx = cast<DefinedOrUnknownSVal>(ER->getIndex());
+
+  const GRState *state = C.getState();
+
+  // Get the size of the array.
+  DefinedOrUnknownSVal NumElements 
+    = C.getStoreManager().getSizeInElements(state, ER->getSuperRegion(), 
+                                         ER->getValueType(C.getASTContext()));
+
+  const GRState *StInBound = state->AssumeInBound(Idx, NumElements, true);
+  const GRState *StOutBound = state->AssumeInBound(Idx, NumElements, false);
+  if (StOutBound && !StInBound) {
+    ExplodedNode *N = C.GenerateSink(StOutBound);
+    if (!N)
+      return;
+  
+    if (!BT)
+      BT = new BuiltinBug("Out-of-bound array access",
+                       "Access out-of-bound array element (buffer overflow)");
+
+    // FIXME: It would be nice to eventually make this diagnostic more clear,
+    // e.g., by referencing the original declaration or by saying *why* this
+    // reference is outside the range.
+
+    // Generate a report for this bug.
+    RangedBugReport *report = 
+      new RangedBugReport(*BT, BT->getDescription(), N);
+
+    report->addRange(S->getSourceRange());
+    C.EmitReport(report);
+    return;
+  }
+  
+  // Array bound check succeeded.  From this point forward the array bound
+  // should always succeed.
+  assert(StInBound);
+  C.addTransition(StInBound);
+}