feat(ivy): first steps towards JIT compilation (#23833)

This commit adds a mechanism by which the @angular/core annotations
for @Component, @Injectable, and @NgModule become decorators which,
when executed at runtime, trigger just-in-time compilation of their
associated types. The activation of these decorators is configured
by the ivy_switch mechanism, ensuring that the Ivy JIT engine does
not get included in Angular bundles unless specifically requested.

PR Close #23833

packages/compiler/src/render3/util.ts

@@ -0,0 +1,38 @@
+/**
+ * @license
+ * Copyright Google Inc. All Rights Reserved.
+ *
+ * Use of this source code is governed by an MIT-style license that can be
+ * found in the LICENSE file at https://angular.io/license
+ */
+
+import {StaticSymbol} from '../aot/static_symbol';
+import * as o from '../output/output_ast';
+import {OutputContext} from '../util';
+
+/**
+ * Convert an object map with `Expression` values into a `LiteralMapExpr`.
+ */
+export function mapToMapExpression(map: {[key: string]: o.Expression}): o.LiteralMapExpr {
+  const result = Object.keys(map).map(key => ({key, value: map[key], quoted: false}));
+  return o.literalMap(result);
+}
+
+/**
+ * Convert metadata into an `Expression` in the given `OutputContext`.
+ *
+ * This operation will handle arrays, references to symbols, or literal `null` or `undefined`.
+ */
+export function convertMetaToOutput(meta: any, ctx: OutputContext): o.Expression {
+  if (Array.isArray(meta)) {
+    return o.literalArr(meta.map(entry => convertMetaToOutput(entry, ctx)));
+  }
+  if (meta instanceof StaticSymbol) {
+    return ctx.importExpr(meta);
+  }
+  if (meta == null) {
+    return o.literal(meta);
+  }
+
+  throw new Error(`Internal error: Unsupported or unknown metadata: ${meta}`);
+}