sammccall created this revision.
sammccall added reviewers: gribozavr, eduucaldas.
Herald added a project: clang.
Herald added a subscriber: cfe-commits.
sammccall requested review of this revision.
Copy/move break invariants (move could be fixed).
Node/Tree should have no public constructors, they're abstract.
Destructor is private to enforce arena allocation.
(Making the constructor of all subclasses private doesn't seem worthwhile)
Repository:
rG LLVM Github Monorepo
https://reviews.llvm.org/D90163
Files:
clang/include/clang/Tooling/Syntax/Tree.h
Index: clang/include/clang/Tooling/Syntax/Tree.h
===================================================================
--- clang/include/clang/Tooling/Syntax/Tree.h
+++ clang/include/clang/Tooling/Syntax/Tree.h
@@ -76,10 +76,20 @@
/// A node in a syntax tree. Each node is either a Leaf (representing tokens)
or
/// a Tree (representing language constructrs).
class Node {
-public:
+protected:
/// Newly created nodes are detached from a tree, parent and sibling links
are
/// set when the node is added as a child to another one.
Node(NodeKind Kind);
+ /// Nodes are allocated on Arenas; the destructor is never called.
+ ~Node() = default;
+
+public:
+ /// Nodes cannot simply be copied without violating tree invariants.
+ Node(const Node &) = delete;
+ Node &operator=(const Node &) = delete;
+ /// Idiomatically, nodes are allocated on an Arena and never moved.
+ Node(Node &&) = delete;
+ Node &operator=(Node &&) = delete;
NodeKind getKind() const { return static_cast<NodeKind>(Kind); }
NodeRole getRole() const { return static_cast<NodeRole>(Role); }
@@ -153,7 +163,6 @@
/// A node that has children and represents a syntactic language construct.
class Tree : public Node {
public:
- using Node::Node;
static bool classof(const Node *N);
Node *getFirstChild() { return FirstChild; }
@@ -170,6 +179,7 @@
}
protected:
+ using Node::Node;
/// Find the first node with a corresponding role.
Node *findChild(NodeRole R);
Index: clang/include/clang/Tooling/Syntax/Tree.h
===================================================================
--- clang/include/clang/Tooling/Syntax/Tree.h
+++ clang/include/clang/Tooling/Syntax/Tree.h
@@ -76,10 +76,20 @@
/// A node in a syntax tree. Each node is either a Leaf (representing tokens) or
/// a Tree (representing language constructrs).
class Node {
-public:
+protected:
/// Newly created nodes are detached from a tree, parent and sibling links are
/// set when the node is added as a child to another one.
Node(NodeKind Kind);
+ /// Nodes are allocated on Arenas; the destructor is never called.
+ ~Node() = default;
+
+public:
+ /// Nodes cannot simply be copied without violating tree invariants.
+ Node(const Node &) = delete;
+ Node &operator=(const Node &) = delete;
+ /// Idiomatically, nodes are allocated on an Arena and never moved.
+ Node(Node &&) = delete;
+ Node &operator=(Node &&) = delete;
NodeKind getKind() const { return static_cast<NodeKind>(Kind); }
NodeRole getRole() const { return static_cast<NodeRole>(Role); }
@@ -153,7 +163,6 @@
/// A node that has children and represents a syntactic language construct.
class Tree : public Node {
public:
- using Node::Node;
static bool classof(const Node *N);
Node *getFirstChild() { return FirstChild; }
@@ -170,6 +179,7 @@
}
protected:
+ using Node::Node;
/// Find the first node with a corresponding role.
Node *findChild(NodeRole R);
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