[analyzer] Refactor recursive symbol reachability check to use symbol_iterator

Reviewers: zaks.anna, dcoughlin

Subscribers: cfe-commits

Differential Revision: https://reviews.llvm.org/D26773

git-svn-id: https://llvm.org/svn/llvm-project/cfe/trunk@287380 91177308-0d34-0410-b5e6-96231b3b80d8

include/clang/StaticAnalyzer/Core/PathSensitive/ProgramState.h

@@ -824,8 +824,9 @@ CB ProgramState::scanReachableSymbols(const MemRegion * const *beg,
 }
 
 /// \class ScanReachableSymbols
-/// A Utility class that allows to visit the reachable symbols using a custom
-/// SymbolVisitor.
+/// A utility class that visits the reachable symbols using a custom
+/// SymbolVisitor. Terminates recursive traversal when the visitor function
+/// returns false.
 class ScanReachableSymbols {
   typedef llvm::DenseSet<const void*> VisitedItems;
 

lib/StaticAnalyzer/Core/ProgramState.cpp

@@ -527,32 +527,17 @@ bool ScanReachableSymbols::scan(nonloc::CompoundVal val) {
 }
 
 bool ScanReachableSymbols::scan(const SymExpr *sym) {
-  bool wasVisited = !visited.insert(sym).second;
-  if (wasVisited)
-    return true;
-
-  if (!visitor.VisitSymbol(sym))
-    return false;
+  for (SymExpr::symbol_iterator SI = sym->symbol_begin(),
+                                SE = sym->symbol_end();
+       SI != SE; ++SI) {
+    bool wasVisited = !visited.insert(*SI).second;
+    if (wasVisited)
+      continue;
 
-  // TODO: should be rewritten using SymExpr::symbol_iterator.
-  switch (sym->getKind()) {
-    case SymExpr::SymbolRegionValueKind:
-    case SymExpr::SymbolConjuredKind:
-    case SymExpr::SymbolDerivedKind:
-    case SymExpr::SymbolExtentKind:
-    case SymExpr::SymbolMetadataKind:
-      break;
-    case SymExpr::SymbolCastKind:
-      return scan(cast<SymbolCast>(sym)->getOperand());
-    case SymExpr::SymIntExprKind:
-      return scan(cast<SymIntExpr>(sym)->getLHS());
-    case SymExpr::IntSymExprKind:
-      return scan(cast<IntSymExpr>(sym)->getRHS());
-    case SymExpr::SymSymExprKind: {
-      const SymSymExpr *x = cast<SymSymExpr>(sym);
-      return scan(x->getLHS()) && scan(x->getRHS());
-    }
+    if (!visitor.VisitSymbol(*SI))
+      return false;
   }
+
   return true;
 }