1 files changed, 96 insertions, 0 deletions
diff --git a/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/UndefinedAssignmentChecker.cpp b/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/UndefinedAssignmentChecker.cpp
new file mode 100644
index 000000000000..7a31efc8cef8
--- /dev/null
+++ b/contrib/llvm/tools/clang/lib/StaticAnalyzer/Checkers/UndefinedAssignmentChecker.cpp
@@ -0,0 +1,96 @@
+//===--- UndefinedAssignmentChecker.h ---------------------------*- C++ -*--==//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This defines UndefinedAssignmentChecker, a builtin check in ExprEngine that
+// checks for assigning undefined values.
+//
+//===----------------------------------------------------------------------===//
+
+#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"
+
+using namespace clang;
+using namespace ento;
+
+namespace {
+class UndefinedAssignmentChecker
+  : public Checker<check::Bind> {
+  mutable std::unique_ptr<BugType> BT;
+
+public:
+  void checkBind(SVal location, SVal val, const Stmt *S,
+                 CheckerContext &C) const;
+};
+}
+
+void UndefinedAssignmentChecker::checkBind(SVal location, SVal val,
+                                           const Stmt *StoreE,
+                                           CheckerContext &C) const {
+  if (!val.isUndef())
+    return;
+
+  // 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;
+
+  ExplodedNode *N = C.generateErrorNode();
+
+  if (!N)
+    return;
+
+  const char *str = "Assigned value is garbage or undefined";
+
+  if (!BT)
+    BT.reset(new BuiltinBug(this, str));
+
+  // Generate a report for this bug.
+  const Expr *ex = nullptr;
+
+  while (StoreE) {
+    if (const BinaryOperator *B = dyn_cast<BinaryOperator>(StoreE)) {
+      if (B->isCompoundAssignmentOp()) {
+        ProgramStateRef state = C.getState();
+        if (state->getSVal(B->getLHS(), C.getLocationContext()).isUndef()) {
+          str = "The left expression of the compound assignment is an "
+                "uninitialized value. The computed value will also be garbage";
+          ex = B->getLHS();
+          break;
+        }
+      }
+
+      ex = B->getRHS();
+      break;
+    }
+
+    if (const DeclStmt *DS = dyn_cast<DeclStmt>(StoreE)) {
+      const VarDecl *VD = dyn_cast<VarDecl>(DS->getSingleDecl());
+      ex = VD->getInit();
+    }
+
+    break;
+  }
+
+  auto R = llvm::make_unique<BugReport>(*BT, str, N);
+  if (ex) {
+    R->addRange(ex->getSourceRange());
+    bugreporter::trackNullOrUndefValue(N, ex, *R);
+  }
+  C.emitReport(std::move(R));
+}
+
+void ento::registerUndefinedAssignmentChecker(CheckerManager &mgr) {
+  mgr.registerChecker<UndefinedAssignmentChecker>();
+}