1 files changed, 102 insertions, 0 deletions
diff --git a/lib/Analysis/VLASizeChecker.cpp b/lib/Analysis/VLASizeChecker.cpp
new file mode 100644
index 000000000000..76e4477449ed
--- /dev/null
+++ b/lib/Analysis/VLASizeChecker.cpp
@@ -0,0 +1,102 @@
+//=== VLASizeChecker.cpp - Undefined dereference 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 two VLASizeCheckers, a builtin check in GRExprEngine that 
+// performs checks for declaration of VLA of undefined or zero size.
+//
+//===----------------------------------------------------------------------===//
+
+#include "clang/Analysis/PathSensitive/Checkers/VLASizeChecker.h"
+#include "clang/Analysis/PathSensitive/GRExprEngine.h"
+#include "clang/Analysis/PathSensitive/BugReporter.h"
+
+using namespace clang;
+
+void *UndefSizedVLAChecker::getTag() {
+  static int x = 0;
+  return &x;
+}
+
+ExplodedNode *UndefSizedVLAChecker::CheckType(QualType T, ExplodedNode *Pred,
+                                              const GRState *state,
+                                              Stmt *S, GRExprEngine &Eng) {
+  GRStmtNodeBuilder &Builder = Eng.getBuilder();
+  BugReporter &BR = Eng.getBugReporter();
+
+  if (VariableArrayType* VLA = dyn_cast<VariableArrayType>(T)) {
+    // FIXME: Handle multi-dimensional VLAs.
+    Expr* SE = VLA->getSizeExpr();
+    SVal Size_untested = state->getSVal(SE);
+
+    if (Size_untested.isUndef()) {
+      if (ExplodedNode* N = Builder.generateNode(S, state, Pred)) {
+        N->markAsSink();
+        if (!BT)
+          BT = new BugType("Declare variable-length array (VLA) of undefined "
+                            "size", "Logic error");
+
+        EnhancedBugReport *R =
+                          new EnhancedBugReport(*BT, BT->getName().c_str(), N);
+        R->addRange(SE->getSourceRange());
+        R->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, SE);
+        BR.EmitReport(R);
+      }
+      return 0;    
+    }
+  }
+  return Pred;
+}
+
+void *ZeroSizedVLAChecker::getTag() {
+  static int x;
+  return &x;
+}
+
+ExplodedNode *ZeroSizedVLAChecker::CheckType(QualType T, ExplodedNode *Pred, 
+                                             const GRState *state, Stmt *S, 
+                                             GRExprEngine &Eng) {
+  GRStmtNodeBuilder &Builder = Eng.getBuilder();
+  BugReporter &BR = Eng.getBugReporter();
+
+  if (VariableArrayType* VLA = dyn_cast<VariableArrayType>(T)) {
+    // FIXME: Handle multi-dimensional VLAs.
+    Expr* SE = VLA->getSizeExpr();
+    SVal Size_untested = state->getSVal(SE);
+
+    DefinedOrUnknownSVal *Size = dyn_cast<DefinedOrUnknownSVal>(&Size_untested);
+    // Undefined size is checked in another checker.
+    if (!Size)
+      return Pred;
+
+    const GRState *zeroState =  state->Assume(*Size, false);
+    state = state->Assume(*Size, true);
+
+    if (zeroState && !state) {
+      if (ExplodedNode* N = Builder.generateNode(S, zeroState, Pred)) {
+        N->markAsSink();
+        if (!BT)
+          BT = new BugType("Declare variable-length array (VLA) of zero size",
+                            "Logic error");
+
+        EnhancedBugReport *R =
+                          new EnhancedBugReport(*BT, BT->getName().c_str(), N);
+        R->addRange(SE->getSourceRange());
+        R->addVisitorCreator(bugreporter::registerTrackNullOrUndefValue, SE);
+        BR.EmitReport(R);
+      }
+    }
+    if (!state)
+      return 0;
+
+    return Builder.generateNode(S, state, Pred);
+  }
+  else
+    return Pred;
+}
+