Move computing of the effective derivative name in DiffRequest. NFC.

include/clad/Differentiator/DiffPlanner.h

@@ -147,6 +147,7 @@ struct DiffRequest {
 
   bool shouldBeRecorded(clang::Expr* E) const;
   bool shouldHaveAdjoint(const clang::VarDecl* VD) const;
+  std::string ComputeDerivativeName() const;
 };
 
   using DiffInterval = std::vector<clang::SourceRange>;

include/clad/Differentiator/VisitorBase.h

@@ -9,6 +9,7 @@
 
 #include "Compatibility.h"
 #include "DerivativeBuilder.h"
+#include "clad/Differentiator/CladUtils.h"
 
 #include "clang/AST/RecursiveASTVisitor.h"
 #include "clang/AST/StmtVisitor.h"
@@ -199,7 +200,7 @@ namespace clad {
     }
     /// For a qualtype QT returns if it's type is Array or Pointer Type
     static bool isArrayOrPointerType(const clang::QualType QT) {
-      return QT->isArrayType() || QT->isPointerType();
+      return utils::isArrayOrPointerType(QT);
     }
 
     clang::CompoundStmt* MakeCompoundStmt(const Stmts& Stmts);

lib/Differentiator/BaseForwardModeVisitor.cpp

@@ -28,6 +28,7 @@
 #include "llvm/Support/SaveAndRestore.h"
 
 #include <algorithm>
+#include <string>
 
 #include "clad/Differentiator/Compatibility.h"
 
@@ -98,7 +99,6 @@ DerivativeAndOverload BaseForwardModeVisitor::Derive() {
   // performed. Mathematically, independent variables are all the function
   // parameters, thus, does not convey the intendend meaning.
   m_IndependentVar = DVI.back().param;
-  std::string derivativeSuffix("");
   // If param is not real (i.e. floating point or integral), a pointer to a
   // real type, or an array of a real type we cannot differentiate it.
   // FIXME: we should support custom numeric types in the future.
@@ -113,7 +113,6 @@ DerivativeAndOverload BaseForwardModeVisitor::Derive() {
       return {};
     }
     m_IndependentVarIndex = diffVarInfo.paramIndexInterval.Start;
-    derivativeSuffix = "_" + std::to_string(m_IndependentVarIndex);
   } else {
     QualType T = m_IndependentVar->getType();
     bool isField = false;
@@ -132,32 +131,9 @@ DerivativeAndOverload BaseForwardModeVisitor::Derive() {
     }
   }
 
-  // If we are differentiating a call operator, that has no parameters,
-  // then the specified independent argument is a member variable of the
-  // class defining the call operator.
-  // Thus, we need to find index of the member variable instead.
-  unsigned argIndex = ~0;
-  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(),
-        std::find(FD->param_begin(), FD->param_end(), m_IndependentVar));
-
-  std::string argInfo = std::to_string(argIndex);
-  for (auto field : diffVarInfo.fields)
-    argInfo += "_" + field;
-
-  std::string s;
-  if (m_DiffReq.CurrentDerivativeOrder > 1)
-    s = std::to_string(m_DiffReq.CurrentDerivativeOrder);
-
   // Check if the function is already declared as a custom derivative.
-  std::string gradientName = m_DiffReq.BaseFunctionName + "_d" + s + "arg" +
-                             argInfo + derivativeSuffix;
+  std::string gradientName = m_DiffReq.ComputeDerivativeName();
+
   // FIXME: We should not use const_cast to get the decl context here.
   // NOLINTNEXTLINE(cppcoreguidelines-pro-type-const-cast)
   auto* DC = const_cast<DeclContext*>(m_DiffReq->getDeclContext());
@@ -428,12 +404,9 @@ DerivativeAndOverload BaseForwardModeVisitor::DerivePushforward() {
   llvm::SaveAndRestore<Scope*> saveScope(getCurrentScope(),
                                          getEnclosingNamespaceOrTUScope());
 
-  auto originalFnEffectiveName = utils::ComputeEffectiveFnName(FD);
-
-  IdentifierInfo* derivedFnII = &m_Context.Idents.get(
-      originalFnEffectiveName + GetPushForwardFunctionSuffix());
+  IdentifierInfo* II = &m_Context.Idents.get(m_DiffReq.ComputeDerivativeName());
   SourceLocation loc{FD->getLocation()};
-  DeclarationNameInfo derivedFnName(derivedFnII, loc);
+  DeclarationNameInfo derivedFnName(II, loc);
 
   // FIXME: We should not use const_cast to get the decl context here.
   // NOLINTNEXTLINE(cppcoreguidelines-pro-type-const-cast)

lib/Differentiator/DiffPlanner.cpp

@@ -669,6 +669,44 @@
     return found != m_ActivityRunInfo.ToBeRecorded.end();
   }
 
+  std::string DiffRequest::ComputeDerivativeName() const {
+    if (Mode != DiffMode::forward && Mode != DiffMode::reverse)
+      return BaseFunctionName + "_" + DiffModeToString(Mode);
+
+    if (DVI.empty())
+      return "<no independent variable specified>";
+
+    DiffInputVarInfo VarInfo = DVI.back();
+    const ValueDecl* IndependentVar = VarInfo.param;
+    unsigned argIndex = ~0;
+    // If we are differentiating a call operator, that has no parameters,
+    // then the specified independent argument is a member variable of the
+    // class defining the call operator.
+    // Thus, we need to find index of the member variable instead.
+    if (Function->param_empty() && Functor)
+      argIndex = std::distance(Functor->field_begin(),
+                               std::find(Functor->field_begin(),
+                                         Functor->field_end(), IndependentVar));
+    else
+      argIndex =
+          std::distance(Function->param_begin(),
+                        std::find(Function->param_begin(),
+                                  Function->param_end(), IndependentVar));
+
+    std::string argInfo = std::to_string(argIndex);
+    for (const std::string& field : VarInfo.fields)
+      argInfo += "_" + field;
+
+    std::string s;
+    if (CurrentDerivativeOrder > 1)
+      s = std::to_string(CurrentDerivativeOrder);
+
+    if (utils::isArrayOrPointerType(IndependentVar->getType()))
+      argInfo += "_" + std::to_string(VarInfo.paramIndexInterval.Start);
+
+    return BaseFunctionName + "_d" + s + "arg" + argInfo;
+  }
+
   ///\returns true on error.
   static bool ProcessInvocationArgs(Sema& S, SourceLocation endLoc,
                                     const RequestOptions& ReqOpts,