1 files changed, 101 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/UndefResultChecker.cpp b/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/UndefResultChecker.cpp
new file mode 100644
index 000000000000..f3f4dce8b17d
--- /dev/null
+++ b/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/UndefResultChecker.cpp
@@ -0,0 +1,101 @@
+//=== UndefResultChecker.cpp ------------------------------------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This defines UndefResultChecker, a builtin check in ExprEngine that 
+// performs checks for undefined results of non-assignment binary operators.
+//
+//===----------------------------------------------------------------------===//
+
+#include "ClangSACheckers.h"
+#include "clang/StaticAnalyzer/Core/BugReporter/BugType.h"
+#include "clang/StaticAnalyzer/Core/Checker.h"
+#include "clang/StaticAnalyzer/Core/CheckerManager.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/CheckerContext.h"
+#include "clang/StaticAnalyzer/Core/PathSensitive/ExprEngine.h"
+#include "llvm/ADT/SmallString.h"
+#include "llvm/Support/raw_ostream.h"
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+class UndefResultChecker 
+  : public Checker< check::PostStmt<BinaryOperator> > {
+
+  mutable std::unique_ptr<BugType> BT;
+
+public:
+  void checkPostStmt(const BinaryOperator *B, CheckerContext &C) const;
+};
+} // end anonymous namespace
+
+void UndefResultChecker::checkPostStmt(const BinaryOperator *B,
+                                       CheckerContext &C) const {
+  ProgramStateRef state = C.getState();
+  const LocationContext *LCtx = C.getLocationContext();
+  if (state->getSVal(B, LCtx).isUndef()) {
+
+    // Do not report assignments of uninitialized values inside swap functions.
+    // This should allow to swap partially uninitialized structs
+    // (radar://14129997)
+    if (const FunctionDecl *EnclosingFunctionDecl =
+        dyn_cast<FunctionDecl>(C.getStackFrame()->getDecl()))
+      if (C.getCalleeName(EnclosingFunctionDecl) == "swap")
+        return;
+
+    // Generate an error node.
+    ExplodedNode *N = C.generateSink();
+    if (!N)
+      return;
+    
+    if (!BT)
+      BT.reset(
+          new BuiltinBug(this, "Result of operation is garbage or undefined"));
+
+    SmallString<256> sbuf;
+    llvm::raw_svector_ostream OS(sbuf);
+    const Expr *Ex = nullptr;
+    bool isLeft = true;
+    
+    if (state->getSVal(B->getLHS(), LCtx).isUndef()) {
+      Ex = B->getLHS()->IgnoreParenCasts();
+      isLeft = true;
+    }
+    else if (state->getSVal(B->getRHS(), LCtx).isUndef()) {
+      Ex = B->getRHS()->IgnoreParenCasts();
+      isLeft = false;
+    }
+    
+    if (Ex) {
+      OS << "The " << (isLeft ? "left" : "right")
+         << " operand of '"
+         << BinaryOperator::getOpcodeStr(B->getOpcode())
+         << "' is a garbage value";
+    }          
+    else {
+      // Neither operand was undefined, but the result is undefined.
+      OS << "The result of the '"
+         << BinaryOperator::getOpcodeStr(B->getOpcode())
+         << "' expression is undefined";
+    }
+    BugReport *report = new BugReport(*BT, OS.str(), N);
+    if (Ex) {
+      report->addRange(Ex->getSourceRange());
+      bugreporter::trackNullOrUndefValue(N, Ex, *report);
+    }
+    else
+      bugreporter::trackNullOrUndefValue(N, B, *report);
+    
+    C.emitReport(report);
+  }
+}
+
+void ento::registerUndefResultChecker(CheckerManager &mgr) {
+  mgr.registerChecker<UndefResultChecker>();
+}