[SyntaxTree][NFC] Refactor function templates into functions taking base class

The refactored functions were
* `isReponsibleForCreatingDeclaration`
* `getQualifiedNameStart`

Differential Revision: https://reviews.llvm.org/D86719

clang/lib/Tooling/Syntax/BuildTree.cpp

@@ -197,18 +197,57 @@ static syntax::NodeKind getOperatorNodeKind(const CXXOperatorCallExpr &E) {
   llvm_unreachable("Unknown OverloadedOperatorKind enum");
 }
 
+/// Get the start of the qualified name. In the examples below it gives the
+/// location of the `^`:
+///     `int ^a;`
+///     `int ^a::S::f(){}`
+static SourceLocation getQualifiedNameStart(NamedDecl *D) {
+  assert((isa<DeclaratorDecl, TypedefNameDecl>(D)) &&
+         "only DeclaratorDecl and TypedefNameDecl are supported.");
+
+  auto DN = D->getDeclName();
+  bool IsAnonymous = DN.isIdentifier() && !DN.getAsIdentifierInfo();
+  if (IsAnonymous)
+    return SourceLocation();
+
+  if (const auto *DD = dyn_cast<DeclaratorDecl>(D)) {
+    if (DD->getQualifierLoc()) {
+      return DD->getQualifierLoc().getBeginLoc();
+    }
+  }
+
+  return D->getLocation();
+}
+
+/// Gets the range of the initializer inside an init-declarator C++ [dcl.decl].
+///     `int a;` -> range of ``,
+///     `int *a = nullptr` -> range of `= nullptr`.
+///     `int a{}` -> range of `{}`.
+///     `int a()` -> range of `()`.
+static SourceRange getInitializerRange(Decl *D) {
+  if (auto *V = dyn_cast<VarDecl>(D)) {
+    auto *I = V->getInit();
+    // Initializers in range-based-for are not part of the declarator
+    if (I && !V->isCXXForRangeDecl())
+      return I->getSourceRange();
+  }
+
+  return SourceRange();
+}
+
 /// Gets the range of declarator as defined by the C++ grammar. E.g.
 ///     `int a;` -> range of `a`,
 ///     `int *a;` -> range of `*a`,
 ///     `int a[10];` -> range of `a[10]`,
 ///     `int a[1][2][3];` -> range of `a[1][2][3]`,
 ///     `int *a = nullptr` -> range of `*a = nullptr`.
-/// FIMXE: \p Name must be a source range, e.g. for `operator+`.
+///     `int S::f(){}` -> range of `S::f()`.
+/// FIXME: \p Name must be a source range, e.g. for `operator+`.
 static SourceRange getDeclaratorRange(const SourceManager &SM, TypeLoc T,
                                       SourceLocation Name,
                                       SourceRange Initializer) {
   SourceLocation Start = GetStartLoc().Visit(T);
-  SourceLocation End = T.getSourceRange().getEnd();
+  SourceLocation End = T.getEndLoc();
   assert(End.isValid());
   if (Name.isValid()) {
     if (Start.isInvalid())
@@ -378,11 +417,9 @@ public:
 
   /// Returns true if \p D is the last declarator in a chain and is thus
   /// reponsible for creating SimpleDeclaration for the whole chain.
-  template <class T>
-  bool isResponsibleForCreatingDeclaration(const T *D) const {
-    static_assert((std::is_base_of<DeclaratorDecl, T>::value ||
-                   std::is_base_of<TypedefNameDecl, T>::value),
-                  "only DeclaratorDecl and TypedefNameDecl are supported.");
+  bool isResponsibleForCreatingDeclaration(const Decl *D) const {
+    assert((isa<DeclaratorDecl, TypedefNameDecl>(D)) &&
+           "only DeclaratorDecl and TypedefNameDecl are supported.");
 
     const Decl *Next = D->getNextDeclInContext();
 
@@ -390,15 +427,14 @@ public:
     if (Next == nullptr) {
       return true;
     }
-    const auto *NextT = dyn_cast<T>(Next);
 
     // Next sibling is not the same type, this one is responsible.
-    if (NextT == nullptr) {
+    if (D->getKind() != Next->getKind()) {
       return true;
     }
     // Next sibling doesn't begin at the same loc, it must be a different
     // declaration, so this declarator is responsible.
-    if (NextT->getBeginLoc() != D->getBeginLoc()) {
+    if (Next->getBeginLoc() != D->getBeginLoc()) {
       return true;
     }
 
@@ -1405,43 +1441,12 @@ public:
   }
 
 private:
-  template <class T> SourceLocation getQualifiedNameStart(T *D) {
-    static_assert((std::is_base_of<DeclaratorDecl, T>::value ||
-                   std::is_base_of<TypedefNameDecl, T>::value),
-                  "only DeclaratorDecl and TypedefNameDecl are supported.");
-
-    auto DN = D->getDeclName();
-    bool IsAnonymous = DN.isIdentifier() && !DN.getAsIdentifierInfo();
-    if (IsAnonymous)
-      return SourceLocation();
-
-    if (const auto *DD = dyn_cast<DeclaratorDecl>(D)) {
-      if (DD->getQualifierLoc()) {
-        return DD->getQualifierLoc().getBeginLoc();
-      }
-    }
-
-    return D->getLocation();
-  }
-
-  SourceRange getInitializerRange(Decl *D) {
-    if (auto *V = dyn_cast<VarDecl>(D)) {
-      auto *I = V->getInit();
-      // Initializers in range-based-for are not part of the declarator
-      if (I && !V->isCXXForRangeDecl())
-        return I->getSourceRange();
-    }
-
-    return SourceRange();
-  }
-
   /// Folds SimpleDeclarator node (if present) and in case this is the last
   /// declarator in the chain it also folds SimpleDeclaration node.
   template <class T> bool processDeclaratorAndDeclaration(T *D) {
-    SourceRange Initializer = getInitializerRange(D);
-    auto Range = getDeclaratorRange(Builder.sourceManager(),
-                                    D->getTypeSourceInfo()->getTypeLoc(),
-                                    getQualifiedNameStart(D), Initializer);
+    auto Range = getDeclaratorRange(
+        Builder.sourceManager(), D->getTypeSourceInfo()->getTypeLoc(),
+        getQualifiedNameStart(D), getInitializerRange(D));
 
     // There doesn't have to be a declarator (e.g. `void foo(int)` only has
     // declaration, but no declarator).
@@ -1464,10 +1469,8 @@ private:
 
     auto ReturnedType = L.getReturnLoc();
     // Build node for the declarator, if any.
-    auto ReturnDeclaratorRange =
-        getDeclaratorRange(this->Builder.sourceManager(), ReturnedType,
-                           /*Name=*/SourceLocation(),
-                           /*Initializer=*/SourceLocation());
+    auto ReturnDeclaratorRange = SourceRange(GetStartLoc().Visit(ReturnedType),
+                                             ReturnedType.getEndLoc());
     syntax::SimpleDeclarator *ReturnDeclarator = nullptr;
     if (ReturnDeclaratorRange.isValid()) {
       ReturnDeclarator = new (allocator()) syntax::SimpleDeclarator;