[analyzer] [NFC] Minor ExprEngineC refactoring

Move a repeated block of code into a function.

Differential Revision: https://reviews.llvm.org/D39584

llvm-svn: 317849

clang/lib/StaticAnalyzer/Core/ExprEngineC.cpp

@@ -20,6 +20,24 @@ using namespace clang;
 using namespace ento;
 using llvm::APSInt;
 
+/// \brief Optionally conjure and return a symbol for offset when processing
+/// an expression \p Expression.
+/// If \p Other is a location, conjure a symbol for \p Symbol
+/// (offset) if it is unknown so that memory arithmetic always
+/// results in an ElementRegion.
+/// \p Count The number of times the current basic block was visited.
+static SVal conjureOffsetSymbolOnLocation(
+    SVal Symbol, SVal Other, Expr* Expression, SValBuilder &svalBuilder,
+    unsigned Count, const LocationContext *LCtx) {
+  QualType Ty = Expression->getType();
+  if (Other.getAs<Loc>() &&
+      Ty->isIntegralOrEnumerationType() &&
+      Symbol.isUnknown()) {
+    return svalBuilder.conjureSymbolVal(Expression, LCtx, Ty, Count);
+  }
+  return Symbol;
+}
+
 void ExprEngine::VisitBinaryOperator(const BinaryOperator* B,
                                      ExplodedNode *Pred,
                                      ExplodedNodeSet &Dst) {
@@ -63,24 +81,13 @@ void ExprEngine::VisitBinaryOperator(const BinaryOperator* B,
       StmtNodeBuilder Bldr(*it, Tmp2, *currBldrCtx);
 
       if (B->isAdditiveOp()) {
-        // If one of the operands is a location, conjure a symbol for the other
-        // one (offset) if it's unknown so that memory arithmetic always
-        // results in an ElementRegion.
         // TODO: This can be removed after we enable history tracking with
         // SymSymExpr.
         unsigned Count = currBldrCtx->blockCount();
-        if (LeftV.getAs<Loc>() &&
-            RHS->getType()->isIntegralOrEnumerationType() &&
-            RightV.isUnknown()) {
-          RightV = svalBuilder.conjureSymbolVal(RHS, LCtx, RHS->getType(),
-                                                Count);
-        }
-        if (RightV.getAs<Loc>() &&
-            LHS->getType()->isIntegralOrEnumerationType() &&
-            LeftV.isUnknown()) {
-          LeftV = svalBuilder.conjureSymbolVal(LHS, LCtx, LHS->getType(),
-                                               Count);
-        }
+        RightV = conjureOffsetSymbolOnLocation(
+            RightV, LeftV, RHS, svalBuilder, Count, LCtx);
+        LeftV = conjureOffsetSymbolOnLocation(
+            LeftV, RightV, LHS, svalBuilder, Count, LCtx);
       }
 
       // Although we don't yet model pointers-to-members, we do need to make