JSSpecCompiler: Add infrastructure to run compiler passes on AST

Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Compiler/CompilerPass.h

@@ -0,0 +1,31 @@
+/*
+ * Copyright (c) 2023, Dan Klishch <danilklishch@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/NonnullRefPtr.h>
+#include <AK/RecursionDecision.h>
+
+#include "Forward.h"
+
+namespace JSSpecCompiler {
+
+class CompilerPass {
+public:
+    CompilerPass(FunctionRef function)
+        : m_function(function)
+    {
+    }
+
+    virtual ~CompilerPass() = default;
+
+    virtual void run() = 0;
+
+protected:
+    FunctionRef m_function;
+};
+
+}

Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Compiler/GenericASTPass.cpp

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+/*
+ * Copyright (c) 2023, Dan Klishch <danilklishch@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#include "Compiler/GenericASTPass.h"
+#include "AST/AST.h"
+#include "Function.h"
+
+namespace JSSpecCompiler {
+
+void RecursiveASTVisitor::run_in_subtree(Tree& tree)
+{
+    NodeSubtreePointer pointer { &tree };
+    recurse(tree, pointer);
+}
+
+void RecursiveASTVisitor::replace_current_node_with(Tree tree)
+{
+    m_current_subtree_pointer->replace_subtree(move(tree));
+}
+
+RecursionDecision RecursiveASTVisitor::recurse(Tree root, NodeSubtreePointer& pointer)
+{
+    RecursionDecision decision;
+
+    m_current_subtree_pointer = &pointer;
+    decision = on_entry(root);
+
+    if (decision == RecursionDecision::Recurse) {
+        for (auto& child : root->subtrees()) {
+            if (recurse(child.get(), child) == RecursionDecision::Break)
+                return RecursionDecision::Break;
+        }
+    }
+
+    m_current_subtree_pointer = &pointer;
+    on_leave(root);
+
+    return RecursionDecision::Continue;
+}
+
+void GenericASTPass::run()
+{
+    run_in_subtree(m_function->m_ast);
+}
+
+}

Meta/Lagom/Tools/CodeGenerators/JSSpecCompiler/Compiler/GenericASTPass.h

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+/*
+ * Copyright (c) 2023, Dan Klishch <danilklishch@gmail.com>
+ *
+ * SPDX-License-Identifier: BSD-2-Clause
+ */
+
+#pragma once
+
+#include <AK/NonnullRefPtr.h>
+#include <AK/RecursionDecision.h>
+
+#include "Compiler/CompilerPass.h"
+
+namespace JSSpecCompiler {
+
+class RecursiveASTVisitor {
+public:
+    virtual ~RecursiveASTVisitor() = default;
+
+    void run_in_subtree(Tree& tree);
+
+protected:
+    virtual RecursionDecision on_entry(Tree) { return RecursionDecision::Recurse; }
+    virtual void on_leave(Tree) { }
+
+    void replace_current_node_with(Tree tree);
+
+private:
+    RecursionDecision recurse(Tree root, NodeSubtreePointer& pointer);
+
+    NodeSubtreePointer* m_current_subtree_pointer = nullptr;
+};
+
+class GenericASTPass
+    : public CompilerPass
+    , protected RecursiveASTVisitor {
+public:
+    GenericASTPass(FunctionRef function)
+        : CompilerPass(function)
+    {
+    }
+
+    void run() override;
+};
+
+}