Add option to disable "acceleration" of require calls.

Summary:
Fixes #986
Closes https://github.com/facebook/prepack/pull/1283

Reviewed By: NTillmann

Differential Revision: D6638592

Pulled By: lukas1994

fbshipit-source-id: d964dc1f8611a9b95aa334e11506fc637705671f

scripts/test-internal.js

@@ -79,6 +79,7 @@ function runTest(name: string, code: string): boolean {
       internalDebug: true,
       compatibility: "jsc-600-1-4-17",
       delayUnsupportedRequires: true,
+      accelerateUnsupportedRequires: true,
       mathRandomSeed: "0",
       errorHandler,
       serialize: true,

src/options.js

@@ -37,6 +37,7 @@ export type SerializerOptions = {
   lazyObjectsRuntime?: string,
   delayInitializations?: boolean,
   delayUnsupportedRequires?: boolean,
+  accelerateUnsupportedRequires?: boolean,
   initializeMoreModules?: boolean,
   internalDebug?: boolean,
   debugScopes?: boolean,

src/prepack-cli.js

@@ -93,6 +93,7 @@ function run(
     logModules: false,
     delayInitializations: false,
     delayUnsupportedRequires: false,
+    accelerateUnsupportedRequires: true,
     internalDebug: false,
     debugScopes: false,
     serialize: false,

src/prepack-options.js

@@ -24,6 +24,7 @@ export type PrepackOptions = {|
   debugNames?: boolean,
   delayInitializations?: boolean,
   delayUnsupportedRequires?: boolean,
+  accelerateUnsupportedRequires?: boolean,
   inputSourceMapFilename?: string,
   internalDebug?: boolean,
   debugScopes?: boolean,
@@ -92,6 +93,7 @@ export function getSerializerOptions({
   heapGraphFilePath,
   delayInitializations = false,
   delayUnsupportedRequires = false,
+  accelerateUnsupportedRequires = true,
   internalDebug = false,
   debugScopes = false,
   logStatistics = false,
@@ -105,6 +107,7 @@ export function getSerializerOptions({
   let result: SerializerOptions = {
     delayInitializations,
     delayUnsupportedRequires,
+    accelerateUnsupportedRequires,
     initializeMoreModules,
     internalDebug,
     debugScopes,

src/serializer/modules.js

@@ -188,6 +188,7 @@ export class ModuleTracer extends Tracer {
                     `accelerated initialization of conditional module ${nestedModuleId} as it's required in an evaluate-for-effects context by module ${moduleIdValue}`
                   );
                   if (
+                    this.modules.accelerateUnsupportedRequires &&
                     nestedEffects !== undefined &&
                     nestedEffects[0] instanceof Value &&
                     this.modules.isModuleInitialized(nestedModuleId)
@@ -288,7 +289,8 @@ export class Modules {
     logger: Logger,
     statistics: SerializerStatistics,
     logModules: boolean,
-    delayUnsupportedRequires: boolean
+    delayUnsupportedRequires: boolean,
+    accelerateUnsupportedRequires: boolean
   ) {
     this.realm = realm;
     this.logger = logger;
@@ -299,6 +301,7 @@ export class Modules {
     this.initializedModules = new Map();
     realm.tracers.push((this.moduleTracer = new ModuleTracer(this, statistics, logModules)));
     this.delayUnsupportedRequires = delayUnsupportedRequires;
+    this.accelerateUnsupportedRequires = accelerateUnsupportedRequires;
     this.disallowDelayingRequiresOverride = false;
   }
 
@@ -311,6 +314,7 @@ export class Modules {
   initializedModules: Map<number | string, Value>;
   active: boolean;
   delayUnsupportedRequires: boolean;
+  accelerateUnsupportedRequires: boolean;
   disallowDelayingRequiresOverride: boolean;
   moduleTracer: ModuleTracer;
 

src/serializer/serializer.js

@@ -47,7 +47,8 @@ export class Serializer {
       this.logger,
       this.statistics,
       !!serializerOptions.logModules,
-      !!serializerOptions.delayUnsupportedRequires
+      !!serializerOptions.delayUnsupportedRequires,
+      !!serializerOptions.accelerateUnsupportedRequires
     );
     this.functions = new Functions(this.realm, serializerOptions.additionalFunctions, this.modules.moduleTracer);
     if (serializerOptions.trace) this.realm.tracers.push(new LoggingTracer(this.realm));