1 files changed, 98 insertions, 0 deletions
diff --git a/lib/Checker/AdjustedReturnValueChecker.cpp b/lib/Checker/AdjustedReturnValueChecker.cpp
new file mode 100644
index 0000000..e95a86b
--- /dev/null
+++ b/lib/Checker/AdjustedReturnValueChecker.cpp
@@ -0,0 +1,98 @@
+//== AdjustedReturnValueChecker.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 AdjustedReturnValueChecker, a simple check to see if the
+// return value of a function call is different than the one the caller thinks
+// it is.
+//
+//===----------------------------------------------------------------------===//
+
+#include "GRExprEngineInternalChecks.h"
+#include "clang/Checker/PathSensitive/GRExprEngine.h"
+#include "clang/Checker/BugReporter/BugReporter.h"
+#include "clang/Checker/PathSensitive/CheckerVisitor.h"
+#include "clang/Basic/SourceManager.h"
+#include "llvm/ADT/SmallString.h"
+
+using namespace clang;
+
+namespace {
+class AdjustedReturnValueChecker : 
+    public CheckerVisitor<AdjustedReturnValueChecker> {      
+public:
+  AdjustedReturnValueChecker() {}
+
+  void PostVisitCallExpr(CheckerContext &C, const CallExpr *CE);
+      
+  static void *getTag() {
+    static int x = 0; return &x;
+  }      
+};
+}
+
+void clang::RegisterAdjustedReturnValueChecker(GRExprEngine &Eng) {
+  Eng.registerCheck(new AdjustedReturnValueChecker());
+}
+
+void AdjustedReturnValueChecker::PostVisitCallExpr(CheckerContext &C,
+                                                   const CallExpr *CE) {
+  
+  // Get the result type of the call.
+  QualType expectedResultTy = CE->getType();
+
+  // Fetch the signature of the called function.
+  const GRState *state = C.getState();
+
+  SVal V = state->getSVal(CE);
+  
+  if (V.isUnknown())
+    return;
+  
+  // Casting to void?  Discard the value.
+  if (expectedResultTy->isVoidType()) {
+    C.GenerateNode(state->BindExpr(CE, UnknownVal()));
+    return;
+  }                   
+
+  const MemRegion *callee = state->getSVal(CE->getCallee()).getAsRegion();
+  if (!callee)
+    return;
+
+  QualType actualResultTy;
+  
+  if (const FunctionTextRegion *FT = dyn_cast<FunctionTextRegion>(callee)) {
+    const FunctionDecl *FD = FT->getDecl();
+    actualResultTy = FD->getResultType();
+  }
+  else if (const BlockDataRegion *BD = dyn_cast<BlockDataRegion>(callee)) {
+    const BlockTextRegion *BR = BD->getCodeRegion();
+    const BlockPointerType *BT =
+      BR->getLocationType(C.getASTContext())->getAs<BlockPointerType>();
+    const FunctionType *FT = BT->getPointeeType()->getAs<FunctionType>();
+    actualResultTy = FT->getResultType();
+  }
+
+  // Can this happen?
+  if (actualResultTy.isNull())
+    return;
+
+  // For now, ignore references.
+  if (actualResultTy->getAs<ReferenceType>())
+    return;
+  
+
+  // Are they the same?
+  if (expectedResultTy != actualResultTy) {
+    // FIXME: Do more checking and actual emit an error. At least performing
+    // the cast avoids some assertion failures elsewhere.
+    SValuator &SVator = C.getSValuator();
+    V = SVator.EvalCast(V, expectedResultTy, actualResultTy);
+    C.GenerateNode(state->BindExpr(CE, V));
+  }
+}