Merge pull request #36230 from ahoppen/pr/ref-count-syntaxdata

[libSyntax] Reference count SyntaxData

include/swift/Syntax/Syntax.h

@@ -54,10 +54,10 @@ const auto NoParent = llvm::None;
 /// convenience methods based on the node's kind.
 class Syntax {
 protected:
-  SyntaxData Data;
+  RC<const SyntaxData> Data;
 
 public:
-  explicit Syntax(const SyntaxData Data) : Data(Data) {}
+  explicit Syntax(const RC<const SyntaxData> &Data) : Data(Data) {}
 
   virtual ~Syntax() {}
 
@@ -84,9 +84,7 @@ public:
   }
 
   /// Get the Data for this Syntax node.
-  const SyntaxData &getData() const {
-    return Data;
-  }
+  const RC<const SyntaxData> &getData() const { return Data; }
 
   /// Cast this Syntax node to a more specific type, asserting it's of the
   /// right kind.
@@ -111,7 +109,7 @@ public:
 
   /// Returns the child index of this node in its parent,
   /// if it has one, otherwise 0.
-  CursorIndex getIndexInParent() const { return getData().getIndexInParent(); }
+  CursorIndex getIndexInParent() const { return getData()->getIndexInParent(); }
 
   /// Return the number of bytes this node takes when spelled out in the source
   size_t getTextLength() const { return getRaw()->getTextLength(); }
@@ -155,8 +153,8 @@ public:
   SWIFT_DEBUG_DUMP;
 
   bool hasSameIdentityAs(const Syntax &Other) const {
-    return Data.getAbsoluteRaw().getNodeId() ==
-           Other.Data.getAbsoluteRaw().getNodeId();
+    return Data->getAbsoluteRaw().getNodeId() ==
+           Other.Data->getAbsoluteRaw().getNodeId();
   }
 
   static bool kindof(SyntaxKind Kind) {
@@ -178,23 +176,23 @@ public:
 
   /// Get the offset at which the leading trivia of this node starts.
   AbsoluteOffsetPosition getAbsolutePositionBeforeLeadingTrivia() const {
-    return Data.getAbsolutePositionBeforeLeadingTrivia();
+    return Data->getAbsolutePositionBeforeLeadingTrivia();
   }
 
   /// Get the offset at which the actual content (i.e. non-triva) of this node
   /// starts.
   AbsoluteOffsetPosition getAbsolutePositionAfterLeadingTrivia() const {
-    return Data.getAbsolutePositionAfterLeadingTrivia();
+    return Data->getAbsolutePositionAfterLeadingTrivia();
   }
 
   /// Get the offset at which the trailing trivia of this node starts.
   AbsoluteOffsetPosition getAbsoluteEndPositionBeforeTrailingTrivia() const {
-    return Data.getAbsoluteEndPositionBeforeTrailingTrivia();
+    return Data->getAbsoluteEndPositionBeforeTrailingTrivia();
   }
 
   /// Get the offset at which the trailing trivia of this node starts.
   AbsoluteOffsetPosition getAbsoluteEndPositionAfterTrailingTrivia() const {
-    return Data.getAbsoluteEndPositionAfterTrailingTrivia();
+    return Data->getAbsoluteEndPositionAfterTrailingTrivia();
   }
 
   // TODO: hasSameStructureAs ?

include/swift/Syntax/SyntaxCollection.h

@@ -56,8 +56,8 @@ class SyntaxCollection : public Syntax {
   friend class Syntax;
 
 private:
-  static SyntaxData makeData(std::initializer_list<Element> &Elements,
-                             const RC<SyntaxArena> &Arena) {
+  static RC<const SyntaxData> makeData(std::initializer_list<Element> &Elements,
+                                       const RC<SyntaxArena> &Arena) {
     std::vector<const RawSyntax *> List;
     List.reserve(Elements.size());
     for (auto &Elt : Elements)
@@ -68,7 +68,7 @@ private:
   }
 
 public:
-  SyntaxCollection(const SyntaxData Data) : Syntax(Data) {}
+  SyntaxCollection(const RC<const SyntaxData> &Data) : Syntax(Data) {}
 
   SyntaxCollection(std::initializer_list<Element> list):
     SyntaxCollection(SyntaxCollection::makeData(list)) {}
@@ -104,7 +104,7 @@ public:
   Element operator[](const size_t Index) const {
     assert(Index < size());
     assert(!empty());
-    return Element(*Data.getChild(Index));
+    return Element(Data->getChild(Index));
   }
 
   /// Return a new collection with the given element added to the end.
@@ -118,7 +118,7 @@ public:
     auto Raw = RawSyntax::makeAndCalcLength(CollectionKind, NewLayout,
                                             getRaw()->getPresence(),
                                             getRaw()->getArena());
-    return SyntaxCollection<CollectionKind, Element>(Data.replacingSelf(Raw));
+    return SyntaxCollection<CollectionKind, Element>(Data->replacingSelf(Raw));
   }
 
   /// Return a new collection with an element removed from the end.
@@ -130,7 +130,7 @@ public:
     auto Raw = RawSyntax::makeAndCalcLength(CollectionKind, NewLayout,
                                             getRaw()->getPresence(),
                                             getRaw()->getArena());
-    return SyntaxCollection<CollectionKind, Element>(Data.replacingSelf(Raw));
+    return SyntaxCollection<CollectionKind, Element>(Data->replacingSelf(Raw));
   }
 
   /// Return a new collection with the given element appended to the front.
@@ -143,7 +143,7 @@ public:
     auto Raw = RawSyntax::makeAndCalcLength(CollectionKind, NewLayout,
                                             getRaw()->getPresence(),
                                             getRaw()->getArena());
-    return SyntaxCollection<CollectionKind, Element>(Data.replacingSelf(Raw));
+    return SyntaxCollection<CollectionKind, Element>(Data->replacingSelf(Raw));
   }
 
   /// Return a new collection with an element removed from the end.
@@ -155,7 +155,7 @@ public:
     auto Raw = RawSyntax::makeAndCalcLength(CollectionKind, NewLayout,
                                             getRaw()->getPresence(),
                                             getRaw()->getArena());
-    return SyntaxCollection<CollectionKind, Element>(Data.replacingSelf(Raw));
+    return SyntaxCollection<CollectionKind, Element>(Data->replacingSelf(Raw));
   }
 
   /// Return a new collection with the Element inserted at index i.
@@ -176,7 +176,7 @@ public:
     auto Raw = RawSyntax::makeAndCalcLength(CollectionKind, NewLayout,
                                             getRaw()->getPresence(),
                                             getRaw()->getArena());
-    return SyntaxCollection<CollectionKind, Element>(Data.replacingSelf(Raw));
+    return SyntaxCollection<CollectionKind, Element>(Data->replacingSelf(Raw));
   }
 
   /// Return a new collection with the element removed at index i.
@@ -189,14 +189,14 @@ public:
     auto Raw = RawSyntax::makeAndCalcLength(CollectionKind, NewLayout,
                                             getRaw()->getPresence(),
                                             getRaw()->getArena());
-    return SyntaxCollection<CollectionKind, Element>(Data.replacingSelf(Raw));
+    return SyntaxCollection<CollectionKind, Element>(Data->replacingSelf(Raw));
   }
 
   /// Return an empty syntax collection of this type.
   SyntaxCollection<CollectionKind, Element> cleared() const {
     auto Raw = RawSyntax::makeAndCalcLength(
         CollectionKind, {}, getRaw()->getPresence(), getRaw()->getArena());
-    return SyntaxCollection<CollectionKind, Element>(Data.replacingSelf(Raw));
+    return SyntaxCollection<CollectionKind, Element>(Data->replacingSelf(Raw));
   }
 
   static bool kindof(SyntaxKind Kind) {

include/swift/Syntax/SyntaxData.h

@@ -51,20 +51,6 @@
 namespace swift {
 namespace syntax {
 
-/// A reference counted box that can contain any type.
-template <typename T>
-class RefCountedBox final
-    : public llvm::ThreadSafeRefCountedBase<RefCountedBox<T>> {
-public:
-  const T Data;
-
-  RefCountedBox(const T Data) : Data(Data) {}
-
-  static RC<RefCountedBox<T>> make(const T &Data) {
-    return RC<RefCountedBox<T>>{new RefCountedBox(Data)};
-  }
-};
-
 /// The class for holding parented syntax.
 ///
 /// This structure should not contain significant public
@@ -72,9 +58,9 @@ public:
 ///
 /// It is essentially a wrapper around \c AbsoluteRawSyntax that also keeps
 /// track of the parent.
-class SyntaxData {
+class SyntaxData : public llvm::ThreadSafeRefCountedBase<SyntaxData> {
   const AbsoluteRawSyntax AbsoluteRaw;
-  RC<RefCountedBox<SyntaxData>> Parent;
+  RC<const SyntaxData> Parent;
 
   /// If this node is the root of a Syntax tree (i.e. \c Parent is \c nullptr ),
   /// the arena in which this node's \c RawSyntax node has been allocated.
@@ -82,8 +68,7 @@ class SyntaxData {
   RC<SyntaxArena> Arena;
 
   /// Create a intermediate node with a parent.
-  SyntaxData(AbsoluteRawSyntax AbsoluteRaw,
-             const RC<RefCountedBox<SyntaxData>> &Parent)
+  SyntaxData(AbsoluteRawSyntax AbsoluteRaw, const RC<const SyntaxData> &Parent)
       : AbsoluteRaw(AbsoluteRaw), Parent(Parent), Arena(nullptr) {}
 
   /// Create a new root node
@@ -94,36 +79,36 @@ class SyntaxData {
 public:
   /// With a new \c RawSyntax node, create a new node from this one and
   /// recursively rebuild the parental chain up to the root.
-  SyntaxData replacingSelf(const RawSyntax *NewRaw) const;
+  RC<const SyntaxData> replacingSelf(const RawSyntax *NewRaw) const;
 
   /// Replace a child in the raw syntax and recursively rebuild the
   /// parental chain up to the root.
   template <typename CursorType>
-  SyntaxData replacingChild(const RawSyntax *RawChild,
-                            CursorType ChildCursor) const {
+  RC<const SyntaxData> replacingChild(const RawSyntax *RawChild,
+                                      CursorType ChildCursor) const {
     auto NewRaw = AbsoluteRaw.getRaw()->replacingChild(ChildCursor, RawChild);
     return replacingSelf(NewRaw);
   }
 
   /// Get the node immediately before this current node that does contain a
-  /// non-missing token. Return \c None if we cannot find such node.
-  Optional<SyntaxData> getPreviousNode() const;
+  /// non-missing token. Return \c nullptr if we cannot find such node.
+  RC<const SyntaxData> getPreviousNode() const;
 
   /// Get the node immediately after this current node that does contain a
-  /// non-missing token. Return \c None if we cannot find such node.
-  Optional<SyntaxData> getNextNode() const;
+  /// non-missing token. Return \c nullptr if we cannot find such node.
+  RC<const SyntaxData> getNextNode() const;
 
-  /// Get the first non-missing token node in this tree. Return \c None if
+  /// Get the first non-missing token node in this tree. Return \c nullptr if
   /// this node does not contain non-missing tokens.
-  Optional<SyntaxData> getFirstToken() const;
+  RC<const SyntaxData> getFirstToken() const;
 
-  /// Get the last non-missing token node in this tree. Return \c None if
+  /// Get the last non-missing token node in this tree. Return \c nullptr if
   /// this node does not contain non-missing tokens.
-  Optional<SyntaxData> getLastToken() const;
+  RC<const SyntaxData> getLastToken() const;
 
   /// Make a new \c SyntaxData node for the tree's root.
-  static SyntaxData makeRoot(AbsoluteRawSyntax AbsoluteRaw) {
-    return SyntaxData(AbsoluteRaw);
+  static RC<const SyntaxData> makeRoot(AbsoluteRawSyntax AbsoluteRaw) {
+    return RC<const SyntaxData>(new SyntaxData(AbsoluteRaw));
   }
 
   const AbsoluteRawSyntax &getAbsoluteRaw() const { return AbsoluteRaw; }
@@ -135,13 +120,7 @@ public:
   SyntaxKind getKind() const { return AbsoluteRaw.getRaw()->getKind(); }
 
   /// Return the parent syntax if there is one.
-  Optional<SyntaxData> getParent() const {
-    if (Parent) {
-      return Parent->Data;
-    } else {
-      return None;
-    }
-  }
+  RC<const SyntaxData> getParent() const { return Parent; }
 
   /// Returns true if this syntax node has a parent.
   bool hasParent() const {
@@ -161,13 +140,13 @@ public:
 
   /// Gets the child at the index specified by the provided cursor.
   template <typename CursorType>
-  Optional<SyntaxData> getChild(CursorType Cursor) const {
+  RC<const SyntaxData> getChild(CursorType Cursor) const {
     return getChild(
         (AbsoluteSyntaxPosition::IndexInParentType)cursorIndex(Cursor));
   }
 
   /// Gets the child at the specified \p Index.
-  Optional<SyntaxData>
+  RC<const SyntaxData>
   getChild(AbsoluteSyntaxPosition::IndexInParentType Index) const;
 
   /// Get the offset at which the leading trivia of this node starts.

include/swift/Syntax/SyntaxNodes.h.gyb

@@ -69,7 +69,7 @@ public:
   };
 %     end
 
-  ${node.name}(const SyntaxData Data) : ${node.base_type}(Data) {
+  ${node.name}(const RC<const SyntaxData> &Data) : ${node.base_type}(Data) {
 %     if node.requires_validation():
       this->validate();
 %     end

include/swift/Syntax/TokenSyntax.h

@@ -33,7 +33,7 @@ protected:
     assert(getRaw()->isToken());
   }
 public:
-  TokenSyntax(const SyntaxData Data) : Syntax(Data) {}
+  TokenSyntax(const RC<const SyntaxData> &Data) : Syntax(Data) {}
 
   static TokenSyntax missingToken(const tok Kind, StringRef Text,
                                   const RC<SyntaxArena> &Arena) {
@@ -50,12 +50,12 @@ public:
 
   TokenSyntax withLeadingTrivia(StringRef Trivia) const {
     auto NewRaw = getRaw()->withLeadingTrivia(Trivia);
-    return TokenSyntax(getData().replacingSelf(NewRaw));
+    return TokenSyntax(getData()->replacingSelf(NewRaw));
   }
 
   TokenSyntax withTrailingTrivia(StringRef Trivia) const {
     auto NewRaw = getRaw()->withTrailingTrivia(Trivia);
-    return TokenSyntax(getData().replacingSelf(NewRaw));
+    return TokenSyntax(getData()->replacingSelf(NewRaw));
   }
 
   /* TODO: If we really need them.

include/swift/Syntax/UnknownSyntax.h

@@ -29,7 +29,7 @@ namespace syntax {
 class UnknownSyntax : public Syntax {
   void validate() const;
 public:
-  UnknownSyntax(const SyntaxData Data) : Syntax(Data) {}
+  UnknownSyntax(const RC<const SyntaxData> &Data) : Syntax(Data) {}
 
   static bool classof(const Syntax *S) {
     return S->isUnknown();