[analyzer] Do not conjure a symbol when we need to propagate taint.

When the solver and SValBuilder cannot reason about symbolic expressions (ex: (x+1)*y ), the analyzer conjures a new symbol with no ties to the past. This helps it to recover some path-sensitivity. However, this breaks the taint propagation.

With this commit, we are going to construct the expression even if we cannot reason about it later on if an operand is tainted.

Also added some comments and asserts.

llvm-svn: 144932

1 files changed, 7 insertions, 7 deletions

diff --git a/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp b/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
index bd63ecf775d..f7924319e5b 100644
--- a/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
+++ b/clang/lib/StaticAnalyzer/Core/SimpleSValBuilder.cpp
@@ -298,7 +298,7 @@ SVal SimpleSValBuilder::evalBinOpNN(const ProgramState *state,
   while (1) {
     switch (lhs.getSubKind()) {
     default:
-      return UnknownVal();
+      return generateUnknownVal(state, op, lhs, rhs, resultTy);
     case nonloc::LocAsIntegerKind: {
       Loc lhsL = cast<nonloc::LocAsInteger>(lhs).getLoc();
       switch (rhs.getSubKind()) {
@@ -321,7 +321,7 @@ SVal SimpleSValBuilder::evalBinOpNN(const ProgramState *state,
               return makeTruthVal(true, resultTy);
             default:
               // This case also handles pointer arithmetic.
-              return UnknownVal();
+              return generateUnknownVal(state, op, lhs, rhs, resultTy);
           }
       }
     }
@@ -333,7 +333,7 @@ SVal SimpleSValBuilder::evalBinOpNN(const ProgramState *state,
         dyn_cast<SymIntExpr>(selhs->getSymbolicExpression());
 
       if (!symIntExpr)
-        return UnknownVal();
+        return generateUnknownVal(state, op, lhs, rhs, resultTy);
 
       // Is this a logical not? (!x is represented as x == 0.)
       if (op == BO_EQ && rhs.isZeroConstant()) {
@@ -381,7 +381,7 @@ SVal SimpleSValBuilder::evalBinOpNN(const ProgramState *state,
       // For now, only handle expressions whose RHS is a constant.
       const nonloc::ConcreteInt *rhsInt = dyn_cast<nonloc::ConcreteInt>(&rhs);
       if (!rhsInt)
-        return UnknownVal();
+        return generateUnknownVal(state, op, lhs, rhs, resultTy);
 
       // If both the LHS and the current expression are additive,
       // fold their constants.
@@ -467,9 +467,9 @@ SVal SimpleSValBuilder::evalBinOpNN(const ProgramState *state,
             if (lhsValue == 0)
               // At this point lhs and rhs have been swapped.
               return rhs;
-            return UnknownVal();
+            return generateUnknownVal(state, op, lhs, rhs, resultTy);
           default:
-            return UnknownVal();
+            return generateUnknownVal(state, op, lhs, rhs, resultTy);
         }
       }
     }
@@ -529,7 +529,7 @@ SVal SimpleSValBuilder::evalBinOpNN(const ProgramState *state,
                              resultTy);
       }
 
-      return UnknownVal();
+      return generateUnknownVal(state, op, lhs, rhs, resultTy);
     }
     }
   }