Update comments in TBRAnalyzer.h.

include/clad/Differentiator/TBRAnalyzer.h

@@ -83,25 +83,14 @@ class TBRAnalyzer : public clang::ConstStmtVisitor<TBRAnalyzer> {
 
   /// Stores all the necessary information about one variable. Fundamental type
   /// variables need only one bit. An object/array needs a separate VarData for
-  /// every its field/element. Reference type variables have their own type for
-  /// convenience reasons and just point to the corresponding VarData.
-  /// UNDEFINED is used whenever the type of a node cannot be determined.
+  /// each field/element. Reference type variables store the clang::Expr* they
+  /// refer to. UNDEFINED is used whenever the type of a node cannot be determined.
 
   /// FIXME: Pointers to objects are considered OBJ_TYPE for simplicity. This
   /// approach might cause problems when the support for pointers is added.
 
-  /// FIXME: Only References to concrete variables are supported. Using
-  /// 'double& x = (cond ? a : b);' or 'double& x = arr[n*k]' (non-const index)
-  /// will lead to unpredictable behavior.
-
-  /// FIXME: Different array elements are considered different variables
-  /// which makes the analysis way more complicated (both in terms of
-  /// readability and performance) when non-constant indices are used. Moreover,
-  /// in such cases we start assuming 'arr[k]' could be any element of arr.
-  /// The only scenario where analysing elements separately would make sense is
-  /// when an element with the same constant index is changed multiple times in
-  /// a row, which seems uncommon. It's worth considering analysing arrays as
-  /// whole structures instead (just one VarData for the whole array).
+  /// FIXME: Add support for references to call expression results.
+  /// 'double& x = f(b);' is not supported.
 
   struct VarData;
   using ObjMap = std::unordered_map<const clang::FieldDecl*, VarData>;
@@ -125,7 +114,7 @@ class TBRAnalyzer : public clang::ConstStmtVisitor<TBRAnalyzer> {
     VarData() = default;
 
     /// Builds a VarData object (and its children) based on the provided type.
-    VarData(QualType QT);
+    VarData(const QualType QT);
 
     /// Erases all children VarData's of this VarData.
     void erase() {
@@ -275,7 +264,7 @@ class TBRAnalyzer : public clang::ConstStmtVisitor<TBRAnalyzer> {
 
   /// Stores modes in a stack (used to retrieve the old mode after entering
   /// a new one).
-  std::vector<int> modeStack;
+  std::vector<short> modeStack;
 
   ASTContext& m_Context;
 
@@ -312,7 +301,7 @@ class TBRAnalyzer : public clang::ConstStmtVisitor<TBRAnalyzer> {
   void setIsRequired(const clang::Expr* E, bool isReq = true);
 
   /// Returns the VarsData of the CFG block being visited.
-  VarsData& getCurBlockVarsData() { return *blockData[curBlockID]; }
+  VarsData& getCurBranch() { return *blockData[curBlockID]; }
 
   //// Modes Setters
   /// Sets the mode manually
@@ -337,7 +326,9 @@ class TBRAnalyzer : public clang::ConstStmtVisitor<TBRAnalyzer> {
   /// Destructor
   ~TBRAnalyzer() {
     for (auto varsData : blockData) {
-      delete varsData;
+      if (varsData) {
+        delete varsData;
+      }
     }
   }