From 8ed27077850651b699992327170b446323e2cc68 Mon Sep 17 00:00:00 2001
From: "petro.zarytskyi" <petro.zarytskyi@gmail.com>
Date: Thu, 3 Oct 2024 23:23:24 +0300
Subject: [PATCH] Remove m_Functor from VisitorBase since it is already stored
 in the diff request

---
 include/clad/Differentiator/VisitorBase.h     |  2 --
 lib/Differentiator/BaseForwardModeVisitor.cpp | 20 +++++++++----------
 2 files changed, 9 insertions(+), 13 deletions(-)

diff --git a/include/clad/Differentiator/VisitorBase.h b/include/clad/Differentiator/VisitorBase.h
index e78149d3d..917088c42 100644
--- a/include/clad/Differentiator/VisitorBase.h
+++ b/include/clad/Differentiator/VisitorBase.h
@@ -132,8 +132,6 @@ namespace clad {
     std::vector<Stmts> m_Blocks;
     /// Stores output variables for vector-valued functions
     VectorOutputs m_VectorOutput;
-    /// The functor type that is currently being differentiated, if any.
-    const clang::CXXRecordDecl* m_Functor = nullptr;
     /// Stores derivative expression of the implicit `this` pointer.
     ///
     /// In the forward mode, `this` pointer derivative expression is of pointer
diff --git a/lib/Differentiator/BaseForwardModeVisitor.cpp b/lib/Differentiator/BaseForwardModeVisitor.cpp
index 0d0bbcb47..fe14227b7 100644
--- a/lib/Differentiator/BaseForwardModeVisitor.cpp
+++ b/lib/Differentiator/BaseForwardModeVisitor.cpp
@@ -60,7 +60,6 @@ bool IsRealNonReferenceType(QualType T) {
 }
 
 DerivativeAndOverload BaseForwardModeVisitor::Derive() {
-  m_Functor = m_DiffReq.Functor;
   const FunctionDecl* FD = m_DiffReq.Function;
   assert(m_DiffReq.Mode == DiffMode::forward);
   assert(!m_DerivativeInFlight &&
@@ -138,11 +137,11 @@ DerivativeAndOverload BaseForwardModeVisitor::Derive() {
   // class defining the call operator.
   // Thus, we need to find index of the member variable instead.
   unsigned argIndex = ~0;
-  if (m_DiffReq->param_empty() && m_Functor)
-    argIndex =
-        std::distance(m_Functor->field_begin(),
-                      std::find(m_Functor->field_begin(),
-                                m_Functor->field_end(), m_IndependentVar));
+  const CXXRecordDecl* functor = m_DiffReq.Functor;
+  if (m_DiffReq->param_empty() && functor)
+    argIndex = std::distance(functor->field_begin(),
+                             std::find(functor->field_begin(),
+                                       functor->field_end(), m_IndependentVar));
   else
     argIndex = std::distance(
         FD->param_begin(),
@@ -296,8 +295,8 @@ DerivativeAndOverload BaseForwardModeVisitor::Derive() {
 
     // Create derived variable for each member variable if we are
     // differentiating a call operator.
-    if (m_Functor) {
-      for (FieldDecl* fieldDecl : m_Functor->fields()) {
+    if (m_DiffReq.Functor) {
+      for (FieldDecl* fieldDecl : m_DiffReq.Functor->fields()) {
         Expr* dInitializer = nullptr;
         QualType fieldType = fieldDecl->getType();
 
@@ -400,7 +399,6 @@ void BaseForwardModeVisitor::ExecuteInsidePushforwardFunctionBlock() {
 
 DerivativeAndOverload BaseForwardModeVisitor::DerivePushforward() {
   const FunctionDecl* FD = m_DiffReq.Function;
-  m_Functor = m_DiffReq.Functor;
   assert(m_DiffReq.Mode == GetPushForwardMode());
   assert(!m_DerivativeInFlight &&
          "Doesn't support recursive diff. Use DiffPlan.");
@@ -884,7 +882,7 @@ StmtDiff BaseForwardModeVisitor::VisitMemberExpr(const MemberExpr* ME) {
   auto clonedME = dyn_cast<MemberExpr>(Clone(ME));
   // Currently, we only differentiate member variables if we are
   // differentiating a call operator.
-  if (m_Functor) {
+  if (m_DiffReq.Functor) {
     if (isa<CXXThisExpr>(ME->getBase()->IgnoreParenImpCasts())) {
       // Try to find the derivative of the member variable wrt independent
       // variable
@@ -956,7 +954,7 @@ BaseForwardModeVisitor::VisitArraySubscriptExpr(const ArraySubscriptExpr* ASE) {
   ValueDecl* VD = nullptr;
   // Derived variables for member variables are also created when we are
   // differentiating a call operator.
-  if (m_Functor) {
+  if (m_DiffReq.Functor) {
     if (auto ME = dyn_cast<MemberExpr>(clonedBase->IgnoreParenImpCasts())) {
       ValueDecl* decl = ME->getMemberDecl();
       auto it = m_Variables.find(decl);