1 files changed, 136 insertions, 0 deletions
diff --git a/lib/StaticAnalyzer/Checkers/AttrNonNullChecker.cpp b/lib/StaticAnalyzer/Checkers/AttrNonNullChecker.cpp
new file mode 100644
index 0000000..e4865b1
--- /dev/null
+++ b/lib/StaticAnalyzer/Checkers/AttrNonNullChecker.cpp
@@ -0,0 +1,136 @@
+//===--- AttrNonNullChecker.h - Undefined arguments checker ----*- C++ -*--===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This defines AttrNonNullChecker, a builtin check in ExprEngine that 
+// performs checks for arguments declared to have nonnull attribute.
+//
+//===----------------------------------------------------------------------===//
+
+#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 AttrNonNullChecker
+  : public CheckerVisitor<AttrNonNullChecker> {
+  BugType *BT;
+public:
+  AttrNonNullChecker() : BT(0) {}
+  static void *getTag() {
+    static int x = 0;
+    return &x;
+  }
+  void PreVisitCallExpr(CheckerContext &C, const CallExpr *CE);
+};
+} // end anonymous namespace
+
+void ento::RegisterAttrNonNullChecker(ExprEngine &Eng) {
+  Eng.registerCheck(new AttrNonNullChecker());
+}
+
+void AttrNonNullChecker::PreVisitCallExpr(CheckerContext &C, 
+                                          const CallExpr *CE) {
+  const GRState *state = C.getState();
+
+  // Check if the callee has a 'nonnull' attribute.
+  SVal X = state->getSVal(CE->getCallee());
+
+  const FunctionDecl* FD = X.getAsFunctionDecl();
+  if (!FD)
+    return;
+
+  const NonNullAttr* Att = FD->getAttr<NonNullAttr>();
+  if (!Att)
+    return;
+
+  // Iterate through the arguments of CE and check them for null.
+  unsigned idx = 0;
+
+  for (CallExpr::const_arg_iterator I=CE->arg_begin(), E=CE->arg_end(); I!=E;
+       ++I, ++idx) {
+
+    if (!Att->isNonNull(idx))
+      continue;
+
+    SVal V = state->getSVal(*I);
+    DefinedSVal *DV = dyn_cast<DefinedSVal>(&V);
+
+    // If the value is unknown or undefined, we can't perform this check.
+    if (!DV)
+      continue;
+
+    if (!isa<Loc>(*DV)) {
+      // If the argument is a union type, we want to handle a potential
+      // transparent_unoin GCC extension.
+      QualType T = (*I)->getType();
+      const RecordType *UT = T->getAsUnionType();
+      if (!UT || !UT->getDecl()->hasAttr<TransparentUnionAttr>())
+        continue;
+      if (nonloc::CompoundVal *CSV = dyn_cast<nonloc::CompoundVal>(DV)) {
+        nonloc::CompoundVal::iterator CSV_I = CSV->begin();
+        assert(CSV_I != CSV->end());
+        V = *CSV_I;
+        DV = dyn_cast<DefinedSVal>(&V);
+        assert(++CSV_I == CSV->end());
+        if (!DV)
+          continue;        
+      }
+      else {
+        // FIXME: Handle LazyCompoundVals?
+        continue;
+      }
+    }
+
+    ConstraintManager &CM = C.getConstraintManager();
+    const GRState *stateNotNull, *stateNull;
+    llvm::tie(stateNotNull, stateNull) = CM.assumeDual(state, *DV);
+
+    if (stateNull && !stateNotNull) {
+      // Generate an error node.  Check for a null node in case
+      // we cache out.
+      if (ExplodedNode *errorNode = C.generateSink(stateNull)) {
+
+        // Lazily allocate the BugType object if it hasn't already been
+        // created. Ownership is transferred to the BugReporter object once
+        // the BugReport is passed to 'EmitWarning'.
+        if (!BT)
+          BT = new BugType("Argument with 'nonnull' attribute passed null",
+                           "API");
+
+        EnhancedBugReport *R =
+          new EnhancedBugReport(*BT,
+                                "Null pointer passed as an argument to a "
+                                "'nonnull' parameter", errorNode);
+
+        // Highlight the range of the argument that was null.
+        const Expr *arg = *I;
+        R->addRange(arg->getSourceRange());
+        R->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, arg);
+
+        // Emit the bug report.
+        C.EmitReport(R);
+      }
+
+      // Always return.  Either we cached out or we just emitted an error.
+      return;
+    }
+
+    // If a pointer value passed the check we should assume that it is
+    // indeed not null from this point forward.
+    assert(stateNotNull);
+    state = stateNotNull;
+  }
+
+  // If we reach here all of the arguments passed the nonnull check.
+  // If 'state' has been updated generated a new node.
+  C.addTransition(state);
+}