yayjarred/prepare-for-libuv

1 files changed, 627 insertions, 0 deletions

diff --git a/src/codegen/bundle-functions.ts b/src/codegen/bundle-functions.ts
new file mode 100644
index 000000000..ebdf0d748
--- /dev/null
+++ b/src/codegen/bundle-functions.ts
@@ -0,0 +1,627 @@
+import { existsSync, mkdirSync, readdirSync, rmSync } from "fs";
+import path from "path";
+import { sliceSourceCode } from "./builtin-parser";
+import { applyGlobalReplacements, define } from "./replacements";
+import { cap, fmtCPPString, low, writeIfNotChanged } from "./helpers";
+import { createInternalModuleRegistry } from "./internal-module-registry-scanner";
+
+console.log("Bundling Bun builtin functions...");
+
+const PARALLEL = false;
+const KEEP_TMP = true;
+
+const CMAKE_BUILD_ROOT = process.argv[2];
+
+if (!CMAKE_BUILD_ROOT) {
+  console.error("Usage: bun bundle-functions.ts <CMAKE_WORK_DIR>");
+  process.exit(1);
+}
+
+const SRC_DIR = path.join(import.meta.dir, "../js/builtins");
+const OUT_DIR = path.join(CMAKE_BUILD_ROOT, "./js");
+const TMP_DIR = path.join(CMAKE_BUILD_ROOT, "./tmp");
+
+const {
+  //
+  requireTransformer,
+} = createInternalModuleRegistry(path.join(import.meta.dir, "../js"));
+
+if (existsSync(TMP_DIR)) rmSync(TMP_DIR, { recursive: true });
+mkdirSync(TMP_DIR, { recursive: true });
+
+interface ParsedBuiltin {
+  name: string;
+  params: string[];
+  directives: Record<string, any>;
+  source: string;
+  async: boolean;
+}
+interface BundledBuiltin {
+  name: string;
+  directives: Record<string, any>;
+  isGetter: boolean;
+  constructAbility: string;
+  constructKind: string;
+  isLinkTimeConstant: boolean;
+  intrinsic: string;
+  overriddenName: string;
+  source: string;
+  params: string[];
+  visibility: string;
+}
+
+/**
+ * Source .ts file --> Array<bundled js function code>
+ */
+async function processFileSplit(filename: string): Promise<{ functions: BundledBuiltin[]; internal: boolean }> {
+  const basename = path.basename(filename, ".ts");
+  let contents = await Bun.file(filename).text();
+
+  contents = applyGlobalReplacements(contents);
+
+  // first approach doesnt work perfectly because we actually need to split each function declaration
+  // and then compile those separately
+
+  const consumeWhitespace = /^\s*/;
+  const consumeTopLevelContent = /^(\/\*|\/\/|type|import|interface|\$|export (?:async )?function|(?:async )?function)/;
+  const consumeEndOfType = /;|.(?=export|type|interface|\$|\/\/|\/\*|function)/;
+
+  const functions: ParsedBuiltin[] = [];
+  let directives: Record<string, any> = {};
+  const bundledFunctions: BundledBuiltin[] = [];
+  let internal = false;
+
+  while (contents.length) {
+    contents = contents.replace(consumeWhitespace, "");
+    if (!contents.length) break;
+    const match = contents.match(consumeTopLevelContent);
+    if (!match) {
+      throw new SyntaxError("Could not process input:\n" + contents.slice(0, contents.indexOf("\n")));
+    }
+    contents = contents.slice(match.index!);
+    if (match[1] === "import") {
+      // TODO: we may want to do stuff with these
+      const i = contents.indexOf(";");
+      contents = contents.slice(i + 1);
+    } else if (match[1] === "/*") {
+      const i = contents.indexOf("*/") + 2;
+      internal ||= contents.slice(0, i).includes("@internal");
+      contents = contents.slice(i);
+    } else if (match[1] === "//") {
+      const i = contents.indexOf("\n") + 1;
+      internal ||= contents.slice(0, i).includes("@internal");
+      contents = contents.slice(i);
+    } else if (match[1] === "type" || match[1] === "export type") {
+      const i = contents.search(consumeEndOfType);
+      contents = contents.slice(i + 1);
+    } else if (match[1] === "interface") {
+      contents = sliceSourceCode(contents, false).rest;
+    } else if (match[1] === "$") {
+      const directive = contents.match(/^\$([a-zA-Z0-9]+)(?:\s*=\s*([^\n]+?))?\s*;?\n/);
+      if (!directive) {
+        throw new SyntaxError("Could not parse directive:\n" + contents.slice(0, contents.indexOf("\n")));
+      }
+      const name = directive[1];
+      let value;
+      try {
+        value = directive[2] ? JSON.parse(directive[2]) : true;
+      } catch (error) {
+        throw new SyntaxError("Could not parse directive value " + directive[2] + " (must be JSON parsable)");
+      }
+      if (name === "constructor") {
+        directives.ConstructAbility = "CanConstruct";
+      } else if (name === "nakedConstructor") {
+        directives.ConstructAbility = "CanConstruct";
+        directives.ConstructKind = "Naked";
+      } else {
+        directives[name] = value;
+      }
+      contents = contents.slice(directive[0].length);
+    } else if (match[1] === "export function" || match[1] === "export async function") {
+      const declaration = contents.match(
+        /^export\s+(async\s+)?function\s+([a-zA-Z0-9]+)\s*\(([^)]*)\)(?:\s*:\s*([^{\n]+))?\s*{?/,
+      );
+      if (!declaration)
+        throw new SyntaxError("Could not parse function declaration:\n" + contents.slice(0, contents.indexOf("\n")));
+
+      const async = !!declaration[1];
+      const name = declaration[2];
+      const paramString = declaration[3];
+      const params =
+        paramString.trim().length === 0 ? [] : paramString.split(",").map(x => x.replace(/:.+$/, "").trim());
+      if (params[0] === "this") {
+        params.shift();
+      }
+
+      const { result, rest } = sliceSourceCode(contents.slice(declaration[0].length - 1), true, x =>
+        requireTransformer(x, SRC_DIR + "/" + basename),
+      );
+
+      functions.push({
+        name,
+        params,
+        directives,
+        source: result.trim().slice(2, -1),
+        async,
+      });
+      contents = rest;
+      directives = {};
+    } else if (match[1] === "function" || match[1] === "async function") {
+      const fnname = contents.match(/^function ([a-zA-Z0-9]+)\(([^)]*)\)(?:\s*:\s*([^{\n]+))?\s*{?/)![1];
+      throw new SyntaxError("All top level functions must be exported: " + fnname);
+    } else {
+      throw new Error("TODO: parse " + match[1]);
+    }
+  }
+
+  for (const fn of functions) {
+    const tmpFile = path.join(TMP_DIR, `${basename}.${fn.name}.ts`);
+
+    // not sure if this optimization works properly in jsc builtins
+    // const useThis = fn.usesThis;
+    const useThis = true;
+
+    // TODO: we should use format=IIFE so we could bundle imports and extra functions.
+    await Bun.write(
+      tmpFile,
+      `// @ts-nocheck
+// GENERATED TEMP FILE - DO NOT EDIT
+// Sourced from ${path.relative(TMP_DIR, filename)}
+
+// do not allow the bundler to rename a symbol to $
+($);
+
+$$capture_start$$(${fn.async ? "async " : ""}${
+        useThis
+          ? `function(${fn.params.join(",")})`
+          : `${fn.params.length === 1 ? fn.params[0] : `(${fn.params.join(",")})`}=>`
+      } {${fn.source}}).$$capture_end$$;
+`,
+    );
+    await Bun.sleep(1);
+    const build = await Bun.build({
+      entrypoints: [tmpFile],
+      define,
+      minify: { syntax: true, whitespace: false },
+    });
+    if (!build.success) {
+      throw new AggregateError(build.logs, "Failed bundling builtin function " + fn.name + " from " + basename + ".ts");
+    }
+    if (build.outputs.length !== 1) {
+      throw new Error("expected one output");
+    }
+    const output = await build.outputs[0].text();
+    const captured = output.match(/\$\$capture_start\$\$([\s\S]+)\.\$\$capture_end\$\$/)![1];
+    const finalReplacement =
+      (fn.directives.sloppy ? captured : captured.replace(/function\s*\(.*?\)\s*{/, '$&"use strict";'))
+        .replace(/^\((async )?function\(/, "($1function (")
+        // .replace(/__intrinsic__lazy\(/g, "globalThis[globalThis.Symbol.for('Bun.lazy')](")
+        .replace(/__intrinsic__/g, "@") + "\n";
+
+    bundledFunctions.push({
+      name: fn.name,
+      directives: fn.directives,
+      source: finalReplacement,
+      params: fn.params,
+      visibility: fn.directives.visibility ?? (fn.directives.linkTimeConstant ? "Private" : "Public"),
+      isGetter: !!fn.directives.getter,
+      constructAbility: fn.directives.ConstructAbility ?? "CannotConstruct",
+      constructKind: fn.directives.ConstructKind ?? "None",
+      isLinkTimeConstant: !!fn.directives.linkTimeConstant,
+      intrinsic: fn.directives.intrinsic ?? "NoIntrinsic",
+      overriddenName: fn.directives.getter
+        ? `"get ${fn.name}"_s`
+        : fn.directives.overriddenName
+        ? `"${fn.directives.overriddenName}"_s`
+        : "ASCIILiteral()",
+    });
+  }
+
+  return {
+    functions: bundledFunctions.sort((a, b) => a.name.localeCompare(b.name)),
+    internal,
+  };
+}
+
+const filesToProcess = readdirSync(SRC_DIR)
+  .filter(x => x.endsWith(".ts") && !x.endsWith(".d.ts"))
+  .sort();
+
+const files: Array<{ basename: string; functions: BundledBuiltin[]; internal: boolean }> = [];
+async function processFile(x: string) {
+  const basename = path.basename(x, ".ts");
+  try {
+    files.push({
+      basename,
+      ...(await processFileSplit(path.join(SRC_DIR, x))),
+    });
+  } catch (error) {
+    console.error("Failed to process file: " + basename + ".ts");
+    console.error(error);
+    process.exit(1);
+  }
+}
+
+// Bun seems to crash if this is parallelized, :(
+if (PARALLEL) {
+  await Promise.all(filesToProcess.map(processFile));
+} else {
+  for (const x of filesToProcess) {
+    await processFile(x);
+  }
+}
+
+// C++ codegen
+let bundledCPP = `// Generated by \`bun src/js/builtins/codegen\`
+// Do not edit by hand.
+namespace Zig { class GlobalObject; }
+#include "root.h"
+#include "config.h"
+#include "JSDOMGlobalObject.h"
+#include "WebCoreJSClientData.h"
+#include <JavaScriptCore/JSObjectInlines.h>
+
+namespace WebCore {
+
+`;
+
+for (const { basename, functions } of files) {
+  bundledCPP += `/* ${basename}.ts */\n`;
+  const lowerBasename = low(basename);
+  for (const fn of functions) {
+    const name = `${lowerBasename}${cap(fn.name)}Code`;
+    bundledCPP += `// ${fn.name}
+const JSC::ConstructAbility s_${name}ConstructAbility = JSC::ConstructAbility::${fn.constructAbility};
+const JSC::ConstructorKind s_${name}ConstructorKind = JSC::ConstructorKind::${fn.constructKind};
+const JSC::ImplementationVisibility s_${name}ImplementationVisibility = JSC::ImplementationVisibility::${fn.visibility};
+const int s_${name}Length = ${fn.source.length};
+static const JSC::Intrinsic s_${name}Intrinsic = JSC::NoIntrinsic;
+const char* const s_${name} = ${fmtCPPString(fn.source)};
+
+`;
+  }
+  bundledCPP += `#define DEFINE_BUILTIN_GENERATOR(codeName, functionName, overriddenName, argumentCount) \\
+JSC::FunctionExecutable* codeName##Generator(JSC::VM& vm) \\
+{\\
+    JSVMClientData* clientData = static_cast<JSVMClientData*>(vm.clientData); \\
+    return clientData->builtinFunctions().${lowerBasename}Builtins().codeName##Executable()->link(vm, nullptr, clientData->builtinFunctions().${lowerBasename}Builtins().codeName##Source(), std::nullopt, s_##codeName##Intrinsic); \\
+}
+WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_CODE(DEFINE_BUILTIN_GENERATOR)
+#undef DEFINE_BUILTIN_GENERATOR
+
+`;
+}
+
+bundledCPP += `
+
+JSBuiltinInternalFunctions::JSBuiltinInternalFunctions(JSC::VM& vm)
+    : m_vm(vm)
+`;
+
+for (const { basename, internal } of files) {
+  if (internal) {
+    bundledCPP += `    , m_${low(basename)}(vm)\n`;
+  }
+}
+
+bundledCPP += `
+{
+    UNUSED_PARAM(vm);
+}
+
+template<typename Visitor>
+void JSBuiltinInternalFunctions::visit(Visitor& visitor)
+{
+`;
+for (const { basename, internal } of files) {
+  if (internal) bundledCPP += `    m_${low(basename)}.visit(visitor);\n`;
+}
+
+bundledCPP += `
+    UNUSED_PARAM(visitor);
+}
+
+template void JSBuiltinInternalFunctions::visit(AbstractSlotVisitor&);
+template void JSBuiltinInternalFunctions::visit(SlotVisitor&);
+
+SUPPRESS_ASAN void JSBuiltinInternalFunctions::initialize(Zig::GlobalObject& globalObject)
+{
+    UNUSED_PARAM(globalObject);
+`;
+
+for (const { basename, internal } of files) {
+  if (internal) {
+    bundledCPP += `    m_${low(basename)}.init(globalObject);\n`;
+  }
+}
+
+bundledCPP += `
+    JSVMClientData& clientData = *static_cast<JSVMClientData*>(m_vm.clientData);
+    Zig::GlobalObject::GlobalPropertyInfo staticGlobals[] = {
+`;
+
+for (const { basename, internal } of files) {
+  if (internal) {
+    bundledCPP += `#define DECLARE_GLOBAL_STATIC(name) \\
+    Zig::GlobalObject::GlobalPropertyInfo( \\
+        clientData.builtinFunctions().${low(basename)}Builtins().name##PrivateName(), ${low(
+      basename,
+    )}().m_##name##Function.get() , JSC::PropertyAttribute::DontDelete | JSC::PropertyAttribute::ReadOnly),
+    WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_FUNCTION_NAME(DECLARE_GLOBAL_STATIC)
+  #undef DECLARE_GLOBAL_STATIC
+  `;
+  }
+}
+
+bundledCPP += `
+    };
+    globalObject.addStaticGlobals(staticGlobals, std::size(staticGlobals));
+    UNUSED_PARAM(clientData);
+}
+
+} // namespace WebCore
+`;
+
+// C++ Header codegen
+let bundledHeader = `// Generated by \`bun src/js/builtins/codegen\`
+// Do not edit by hand.
+#pragma once
+namespace Zig { class GlobalObject; }
+#include "root.h"
+#include <JavaScriptCore/BuiltinUtils.h>
+#include <JavaScriptCore/Identifier.h>
+#include <JavaScriptCore/JSFunction.h>
+#include <JavaScriptCore/UnlinkedFunctionExecutable.h>
+#include <JavaScriptCore/VM.h>
+#include <JavaScriptCore/WeakInlines.h>
+
+namespace JSC {
+class FunctionExecutable;
+}
+
+namespace WebCore {
+`;
+for (const { basename, functions, internal } of files) {
+  bundledHeader += `/* ${basename}.ts */
+`;
+  const lowerBasename = low(basename);
+
+  for (const fn of functions) {
+    const name = `${lowerBasename}${cap(fn.name)}Code`;
+    bundledHeader += `// ${fn.name}
+#define WEBCORE_BUILTIN_${basename.toUpperCase()}_${fn.name.toUpperCase()} 1
+extern const char* const s_${name};
+extern const int s_${name}Length;
+extern const JSC::ConstructAbility s_${name}ConstructAbility;
+extern const JSC::ConstructorKind s_${name}ConstructorKind;
+extern const JSC::ImplementationVisibility s_${name}ImplementationVisibility;
+
+`;
+  }
+  bundledHeader += `#define WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_DATA(macro) \\\n`;
+  for (const fn of functions) {
+    bundledHeader += `    macro(${fn.name}, ${lowerBasename}${cap(fn.name)}, ${fn.params.length}) \\\n`;
+  }
+  bundledHeader += "\n";
+  bundledHeader += `#define WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_CODE(macro) \\\n`;
+  for (const fn of functions) {
+    const name = `${lowerBasename}${cap(fn.name)}Code`;
+    bundledHeader += `    macro(${name}, ${fn.name}, ${fn.overriddenName}, s_${name}Length) \\\n`;
+  }
+  bundledHeader += "\n";
+  bundledHeader += `#define WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_FUNCTION_NAME(macro) \\\n`;
+  for (const fn of functions) {
+    bundledHeader += `    macro(${fn.name}) \\\n`;
+  }
+  bundledHeader += `
+#define DECLARE_BUILTIN_GENERATOR(codeName, functionName, overriddenName, argumentCount) \\
+    JSC::FunctionExecutable* codeName##Generator(JSC::VM&);
+
+WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_CODE(DECLARE_BUILTIN_GENERATOR)
+#undef DECLARE_BUILTIN_GENERATOR
+
+class ${basename}BuiltinsWrapper : private JSC::WeakHandleOwner {
+public:
+    explicit ${basename}BuiltinsWrapper(JSC::VM& vm)
+        : m_vm(vm)
+        WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_FUNCTION_NAME(INITIALIZE_BUILTIN_NAMES)
+#define INITIALIZE_BUILTIN_SOURCE_MEMBERS(name, functionName, overriddenName, length) , m_##name##Source(JSC::makeSource(StringImpl::createWithoutCopying(s_##name, length), { }, JSC::SourceTaintedOrigin::Untainted))
+        WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_CODE(INITIALIZE_BUILTIN_SOURCE_MEMBERS)
+#undef INITIALIZE_BUILTIN_SOURCE_MEMBERS
+    {
+    }
+
+#define EXPOSE_BUILTIN_EXECUTABLES(name, functionName, overriddenName, length) \\
+    JSC::UnlinkedFunctionExecutable* name##Executable(); \\
+    const JSC::SourceCode& name##Source() const { return m_##name##Source; }
+    WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_CODE(EXPOSE_BUILTIN_EXECUTABLES)
+#undef EXPOSE_BUILTIN_EXECUTABLES
+
+    WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_FUNCTION_NAME(DECLARE_BUILTIN_IDENTIFIER_ACCESSOR)
+
+    void exportNames();
+
+private:
+    JSC::VM& m_vm;
+
+    WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_FUNCTION_NAME(DECLARE_BUILTIN_NAMES)
+
+#define DECLARE_BUILTIN_SOURCE_MEMBERS(name, functionName, overriddenName, length) \\
+    JSC::SourceCode m_##name##Source;\\
+    JSC::Weak<JSC::UnlinkedFunctionExecutable> m_##name##Executable;
+    WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_CODE(DECLARE_BUILTIN_SOURCE_MEMBERS)
+#undef DECLARE_BUILTIN_SOURCE_MEMBERS
+
+};
+
+#define DEFINE_BUILTIN_EXECUTABLES(name, functionName, overriddenName, length) \\
+inline JSC::UnlinkedFunctionExecutable* ${basename}BuiltinsWrapper::name##Executable() \\
+{\\
+    if (!m_##name##Executable) {\\
+        JSC::Identifier executableName = functionName##PublicName();\\
+        if (overriddenName)\\
+            executableName = JSC::Identifier::fromString(m_vm, overriddenName);\\
+        m_##name##Executable = JSC::Weak<JSC::UnlinkedFunctionExecutable>(JSC::createBuiltinExecutable(m_vm, m_##name##Source, executableName, s_##name##ImplementationVisibility, s_##name##ConstructorKind, s_##name##ConstructAbility), this, &m_##name##Executable);\\
+    }\\
+    return m_##name##Executable.get();\\
+}
+WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_CODE(DEFINE_BUILTIN_EXECUTABLES)
+#undef DEFINE_BUILTIN_EXECUTABLES
+
+inline void ${basename}BuiltinsWrapper::exportNames()
+{
+#define EXPORT_FUNCTION_NAME(name) m_vm.propertyNames->appendExternalName(name##PublicName(), name##PrivateName());
+    WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_FUNCTION_NAME(EXPORT_FUNCTION_NAME)
+#undef EXPORT_FUNCTION_NAME
+}
+`;
+
+  if (internal) {
+    bundledHeader += `class ${basename}BuiltinFunctions {
+public:
+    explicit ${basename}BuiltinFunctions(JSC::VM& vm) : m_vm(vm) { }
+
+    void init(JSC::JSGlobalObject&);
+    template<typename Visitor> void visit(Visitor&);
+
+public:
+    JSC::VM& m_vm;
+
+#define DECLARE_BUILTIN_SOURCE_MEMBERS(functionName) \\
+    JSC::WriteBarrier<JSC::JSFunction> m_##functionName##Function;
+    WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_FUNCTION_NAME(DECLARE_BUILTIN_SOURCE_MEMBERS)
+#undef DECLARE_BUILTIN_SOURCE_MEMBERS
+};
+
+inline void ${basename}BuiltinFunctions::init(JSC::JSGlobalObject& globalObject)
+{
+#define EXPORT_FUNCTION(codeName, functionName, overriddenName, length) \\
+    m_##functionName##Function.set(m_vm, &globalObject, JSC::JSFunction::create(m_vm, codeName##Generator(m_vm), &globalObject));
+    WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_CODE(EXPORT_FUNCTION)
+#undef EXPORT_FUNCTION
+}
+
+template<typename Visitor>
+inline void ${basename}BuiltinFunctions::visit(Visitor& visitor)
+{
+#define VISIT_FUNCTION(name) visitor.append(m_##name##Function);
+    WEBCORE_FOREACH_${basename.toUpperCase()}_BUILTIN_FUNCTION_NAME(VISIT_FUNCTION)
+#undef VISIT_FUNCTION
+}
+
+template void ${basename}BuiltinFunctions::visit(JSC::AbstractSlotVisitor&);
+template void ${basename}BuiltinFunctions::visit(JSC::SlotVisitor&);
+    `;
+  }
+}
+bundledHeader += `class JSBuiltinFunctions {
+public:
+    explicit JSBuiltinFunctions(JSC::VM& vm)
+        : m_vm(vm)
+`;
+
+for (const { basename } of files) {
+  bundledHeader += `        , m_${low(basename)}Builtins(m_vm)\n`;
+}
+
+bundledHeader += `
+  {
+`;
+
+for (const { basename, internal } of files) {
+  if (internal) {
+    bundledHeader += `        m_${low(basename)}Builtins.exportNames();\n`;
+  }
+}
+
+bundledHeader += `    }
+`;
+
+for (const { basename } of files) {
+  bundledHeader += `    ${basename}BuiltinsWrapper& ${low(basename)}Builtins() { return m_${low(
+    basename,
+  )}Builtins; }\n`;
+}
+
+bundledHeader += `
+private:
+    JSC::VM& m_vm;
+`;
+
+for (const { basename } of files) {
+  bundledHeader += `    ${basename}BuiltinsWrapper m_${low(basename)}Builtins;\n`;
+}
+
+bundledHeader += `;
+};
+
+class JSBuiltinInternalFunctions {
+public:
+    explicit JSBuiltinInternalFunctions(JSC::VM&);
+
+    template<typename Visitor> void visit(Visitor&);
+    void initialize(Zig::GlobalObject&);
+`;
+
+for (const { basename, internal } of files) {
+  if (internal) {
+    bundledHeader += `    ${basename}BuiltinFunctions& ${low(basename)}() { return m_${low(basename)}; }\n`;
+  }
+}
+
+bundledHeader += `
+private:
+    JSC::VM& m_vm;
+`;
+
+for (const { basename, internal } of files) {
+  if (internal) {
+    bundledHeader += `    ${basename}BuiltinFunctions m_${low(basename)};\n`;
+  }
+}
+
+bundledHeader += `
+};
+
+} // namespace WebCore
+`;
+
+writeIfNotChanged(path.join(OUT_DIR, "WebCoreJSBuiltins.h"), bundledHeader);
+writeIfNotChanged(path.join(OUT_DIR, "WebCoreJSBuiltins.cpp"), bundledCPP);
+
+// Generate TS types
+let dts = `// Generated by \`bun src/js/builtins/codegen\`
+// Do not edit by hand.
+type RemoveThis<F> = F extends (this: infer T, ...args: infer A) => infer R ? (...args: A) => R : F;
+`;
+
+for (const { basename, functions, internal } of files) {
+  if (internal) {
+    dts += `\n// ${basename}.ts\n`;
+    for (const fn of functions) {
+      dts += `declare const \$${fn.name}: RemoveThis<typeof import("${path.relative(
+        OUT_DIR,
+        path.join(SRC_DIR, basename),
+      )}")[${JSON.stringify(fn.name)}]>;\n`;
+    }
+  }
+}
+
+writeIfNotChanged(path.join(OUT_DIR, "WebCoreJSBuiltins.d.ts"), dts);
+
+const totalJSSize = files.reduce(
+  (acc, { functions }) => acc + functions.reduce((acc, fn) => acc + fn.source.length, 0),
+  0,
+);
+
+if (!KEEP_TMP) {
+  await rmSync(TMP_DIR, { recursive: true });
+}
+
+console.log(
+  `Embedded JS size: %s bytes (across %s functions, %s files)`,
+  totalJSSize,
+  files.reduce((acc, { functions }) => acc + functions.length, 0),
+  files.length,
+);
+console.log(`[${performance.now().toFixed(1)}ms]`);