Create an old program to be used in snapshot. (#3644)

cli/js/compiler.ts

@@ -6,6 +6,7 @@ import "./globals.ts";
 import "./ts_global.d.ts";
 
 import { TranspileOnlyResult } from "./compiler_api.ts";
+import { oldProgram } from "./compiler_bootstrap.ts";
 import { setRootExports } from "./compiler_bundler.ts";
 import {
   defaultBundlerOptions,
@@ -73,7 +74,7 @@ interface CompileResult {
 
 // bootstrap the runtime environment, this gets called as the isolate is setup
 self.denoMain = function denoMain(compilerType?: string): void {
-  os.start(true, compilerType || "TS");
+  os.start(true, compilerType ?? "TS");
 };
 
 // bootstrap the worker environment, this gets called as the isolate is setup
@@ -135,7 +136,12 @@ self.compilerMain = function compilerMain(): void {
         // to generate the program and possibly emit it.
         if (!diagnostics || (diagnostics && diagnostics.length === 0)) {
           const options = host.getCompilationSettings();
-          const program = ts.createProgram(rootNames, options, host);
+          const program = ts.createProgram({
+            rootNames,
+            options,
+            host,
+            oldProgram
+          });
 
           diagnostics = ts
             .getPreEmitDiagnostics(program)
@@ -213,11 +219,12 @@ self.compilerMain = function compilerMain(): void {
         }
         host.mergeOptions(...compilerOptions);
 
-        const program = ts.createProgram(
+        const program = ts.createProgram({
           rootNames,
-          host.getCompilationSettings(),
-          host
-        );
+          options: host.getCompilationSettings(),
+          host,
+          oldProgram
+        });
 
         if (bundle) {
           setRootExports(program, rootNames[0]);

cli/js/compiler_bootstrap.ts

@@ -0,0 +1,34 @@
+// Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
+
+import { ASSETS, Host } from "./compiler_host.ts";
+import { core } from "./core.ts";
+import * as dispatch from "./dispatch.ts";
+import { sendSync } from "./dispatch_json.ts";
+
+// This registers ops that are available during the snapshotting process.
+const ops = core.ops();
+for (const [name, opId] of Object.entries(ops)) {
+  const opName = `OP_${name.toUpperCase()}`;
+  // TODO This type casting is dangerous, and should be improved when the same
+  // code in `os.ts` is done.
+  // eslint-disable-next-line @typescript-eslint/no-explicit-any
+  (dispatch as any)[opName] = opId;
+}
+
+const host = new Host({ writeFile(): void {} });
+const options = host.getCompilationSettings();
+
+/** Used to generate the foundational AST for all other compilations, so it can
+ * be cached as part of the snapshot and available to speed up startup */
+export const oldProgram = ts.createProgram({
+  rootNames: [`${ASSETS}/bootstrap.ts`],
+  options,
+  host
+});
+
+/** A module loader which is concatenated into bundle files.  We read all static
+ * assets during the snapshotting process, which is why this is located in
+ * compiler_bootstrap. */
+export const bundleLoader = sendSync(dispatch.OP_FETCH_ASSET, {
+  name: "bundle_loader.js"
+});

cli/js/compiler_bundler.ts

@@ -1,7 +1,6 @@
 // Copyright 2018-2020 the Deno authors. All rights reserved. MIT license.
 
-import * as dispatch from "./dispatch.ts";
-import { sendSync } from "./dispatch_json.ts";
+import { bundleLoader } from "./compiler_bootstrap.ts";
 import {
   assert,
   commonPath,
@@ -9,11 +8,6 @@ import {
   CHAR_FORWARD_SLASH
 } from "./util.ts";
 
-const BUNDLE_LOADER = "bundle_loader.js";
-
-/** A loader of bundled modules that we will inline into any bundle outputs. */
-let bundleLoader: string;
-
 /** Local state of what the root exports are of a root module. */
 let rootExports: string[] | undefined;
 
@@ -40,12 +34,6 @@ export function buildBundle(
   data: string,
   sourceFiles: readonly ts.SourceFile[]
 ): string {
-  // we can only do this once we are bootstrapped and easiest way to do it is
-  // inline here
-  if (!bundleLoader) {
-    bundleLoader = sendSync(dispatch.OP_FETCH_ASSET, { name: BUNDLE_LOADER });
-  }
-
   // when outputting to AMD and a single outfile, TypeScript makes up the module
   // specifiers which are used to define the modules, and doesn't expose them
   // publicly, so we have to try to replicate

cli/js/compiler_host.ts

@@ -18,7 +18,7 @@ export interface ConfigureResponse {
   diagnostics?: ts.Diagnostic[];
 }
 
-const ASSETS = "$asset$";
+export const ASSETS = "$asset$";
 
 /** Options that need to be used when generating a bundle (either trusted or
  * runtime). */
@@ -129,11 +129,11 @@ export class Host implements ts.CompilerHost {
   private _writeFile: WriteFileCallback;
 
   private _getAsset(filename: string): SourceFile {
-    const sourceFile = SourceFile.get(filename);
+    const url = filename.split("/").pop()!;
+    const sourceFile = SourceFile.get(url);
     if (sourceFile) {
       return sourceFile;
     }
-    const url = filename.split("/").pop()!;
     const name = url.includes(".") ? url : `${url}.d.ts`;
     const sourceCode = sendSync(dispatch.OP_FETCH_ASSET, { name });
     return new SourceFile({
@@ -238,13 +238,15 @@ export class Host implements ts.CompilerHost {
         : SourceFile.get(fileName);
       assert(sourceFile != null);
       if (!sourceFile.tsSourceFile) {
+        assert(sourceFile.sourceCode != null);
         sourceFile.tsSourceFile = ts.createSourceFile(
           fileName,
           sourceFile.sourceCode,
           languageVersion
         );
+        delete sourceFile.sourceCode;
       }
-      return sourceFile!.tsSourceFile;
+      return sourceFile.tsSourceFile;
     } catch (e) {
       if (onError) {
         onError(String(e));

cli/js/compiler_sourcefile.ts

@@ -61,7 +61,7 @@ export class SourceFile {
 
   mediaType!: MediaType;
   processed = false;
-  sourceCode!: string;
+  sourceCode?: string;
   tsSourceFile?: ts.SourceFile;
   url!: string;
 

cli/js/dispatch.ts

@@ -66,13 +66,16 @@ export let OP_READ_LINK: number;
 export let OP_TRUNCATE: number;
 export let OP_MAKE_TEMP_DIR: number;
 export let OP_CWD: number;
-export let OP_FETCH_ASSET: number;
 export let OP_DIAL_TLS: number;
 export let OP_HOSTNAME: number;
 export let OP_OPEN_PLUGIN: number;
 export let OP_COMPILE: number;
 export let OP_TRANSPILE: number;
 
+/** **WARNING:** This is only available during the snapshotting process and is
+ * unavailable at runtime. */
+export let OP_FETCH_ASSET: number;
+
 const PLUGIN_ASYNC_HANDLER_MAP: Map<number, AsyncHandler> = new Map();
 
 export function setPluginAsyncHandler(

cli/js/dispatch_json.ts

@@ -62,7 +62,7 @@ export function sendSync(
   const resUi8 = core.dispatch(opId, argsUi8, zeroCopy);
   util.assert(resUi8 != null);
 
-  const res = decode(resUi8!);
+  const res = decode(resUi8);
   util.assert(res.promiseId == null);
   return unwrapResponse(res);
 }