Issue #2089 - Optimize Promise.then and Promise.all/race with default resolving functions

Based-on: m-c 1401508,1412200,1473970/{1-4}

js/src/jit-test/tests/debug/Promise-race-dependent-promises.js

@@ -0,0 +1,46 @@
+// Promise.race(...) may add a dummy PromiseReaction which is only used for the
+// debugger.
+//
+// See BlockOnPromise when called from PerformPromiseRace for when this dummy
+// reaction is created.
+
+var g = newGlobal();
+var dbg = new Debugger();
+var gw = dbg.addDebuggee(g);
+
+function test(withFastPath) {
+    g.eval(`
+        function newPromiseCapability() {
+            var resolve, reject, promise = new Promise(function(r1, r2) {
+                resolve = r1;
+                reject = r2;
+            });
+            return {promise, resolve, reject};
+        }
+
+        var {promise: alwaysPending} = newPromiseCapability();
+
+        if (!${withFastPath}) {
+            // Disable the BlockOnPromise fast path by giving |alwaysPending| a
+            // non-default "then" function property. This will ensure the dummy
+            // reaction is created.
+            alwaysPending.then = function() {};
+        }
+
+        var result = Promise.race([alwaysPending]);
+    `);
+
+    var alwaysPending = gw.makeDebuggeeValue(g.alwaysPending);
+    var result = gw.makeDebuggeeValue(g.result);
+
+    assertEq(alwaysPending.promiseDependentPromises.length, 1);
+    assertEq(alwaysPending.promiseDependentPromises[0], result);
+
+    assertEq(result.promiseDependentPromises.length, 0);
+}
+
+// No dummy reaction created when the fast path is taken.
+test(true);
+
+// Dummy reaction is created when we can't take the fast path.
+test(false);

js/src/jit-test/tests/promise/debugger-reaction-does-not-resolve.js

@@ -0,0 +1,71 @@
+// Promise.race(...) may add a dummy PromiseReaction which is only used for the
+// debugger. Ensure that this dummy reaction can't influence the normal Promise
+// resolution behaviour.
+//
+// See BlockOnPromise when called from PerformPromiseRace for when this dummy
+// reaction is created.
+
+function newPromiseCapability() {
+    var resolve, reject, promise = new Promise(function(r1, r2) {
+        resolve = r1;
+        reject = r2;
+    });
+    return {promise, resolve, reject};
+}
+
+function neverCalled() {
+    // Quit with non-zero exit code to ensure a test suite error is shown,
+    // even when this function is called within promise handlers which normally
+    // swallow any exceptions.
+    quit(1);
+}
+
+var c = 0;
+var g_resolve;
+
+var resolvedValues = [];
+
+function resolveCapability(v) {
+   resolvedValues.push(v);
+}
+
+class P extends Promise {
+    constructor(executor) {
+        // Only the very first object created through this constructor gets
+        // special treatment, all other invocations create built-in Promise
+        // objects.
+        if (c++ > 1) {
+            return new Promise(executor);
+        }
+
+        executor(resolveCapability, neverCalled);
+
+        var {promise, resolve} = newPromiseCapability();
+        g_resolve = resolve;
+
+        // Use an async function to create a Promise without resolving functions.
+        var p = async function(){ await promise; return 456; }();
+
+        // Ensure the species constructor is not the built-in Promise constructor
+        // to avoid falling into the fast path.
+        p.constructor = {
+            [Symbol.species]: P
+        };
+
+        return p;
+    }
+}
+
+var {promise: alwaysPending} = newPromiseCapability();
+
+// The promise returned from race() should never be resolved.
+P.race([alwaysPending]).then(neverCalled, neverCalled);
+
+g_resolve(123);
+
+drainJobQueue();
+
+// Check |resolvedValues| to ensure resolving functions were properly called.
+assertEq(resolvedValues.length, 2);
+assertEq(resolvedValues[0], alwaysPending);
+assertEq(resolvedValues[1], 456);

js/src/jit-test/tests/promise/resolve-promise-scripted-and-api.js

@@ -0,0 +1,15 @@
+function newPromiseCapability() {
+    var resolve, reject, promise = new Promise(function(r1, r2) {
+        resolve = r1;
+        reject = r2;
+    });
+    return {promise, resolve, reject};
+}
+
+
+var {promise, resolve} = newPromiseCapability();
+
+resolve(Promise.resolve(0));
+
+// Don't assert when the Promise was already resolved.
+resolvePromise(promise, 123);

js/src/jit-test/tests/promise/settle-now-breaks-all-invariants-1.js

@@ -0,0 +1,21 @@
+// Test we don't assert when the promise is settled after enqueuing a PromiseReactionJob.
+
+function newPromiseCapability() {
+    var resolve, reject, promise = new Promise(function(r1, r2) {
+        resolve = r1;
+        reject = r2;
+    });
+    return {promise, resolve, reject};
+}
+
+
+var {promise, resolve} = newPromiseCapability();
+
+var p = Promise.resolve(0);
+
+// Enqueue a PromiseResolveThenableJob followed by a PromiseReactionJob.
+resolve(p);
+
+// The PromiseReactionJob expects a pending promise, but this settlePromiseNow
+// call will already have settled the promise.
+settlePromiseNow(promise);

js/src/jit-test/tests/promise/settle-now-breaks-all-invariants-10.js

@@ -0,0 +1,18 @@
+// Don't assert when the promise in the resolving functions is wrapped in a CCW.
+
+function newPromiseCapability(newTarget) {
+    var resolve, reject, promise = Reflect.construct(Promise, [function(r1, r2) {
+        resolve = r1;
+        reject = r2;
+    }], newTarget);
+    return {promise, resolve, reject};
+}
+
+var g = newGlobal();
+
+var {promise, resolve} = newPromiseCapability(g.Promise);
+
+g.settlePromiseNow(promise);
+
+// Don't assert when resolving the promise.
+resolve(0);

js/src/jit-test/tests/promise/settle-now-breaks-all-invariants-11.js

@@ -0,0 +1,18 @@
+// Don't assert when the promise in the resolving functions is wrapped in a CCW.
+
+function newPromiseCapability(newTarget) {
+    var resolve, reject, promise = Reflect.construct(Promise, [function(r1, r2) {
+        resolve = r1;
+        reject = r2;
+    }], newTarget);
+    return {promise, resolve, reject};
+}
+
+var g = newGlobal();
+
+var {promise, reject} = newPromiseCapability(g.Promise);
+
+g.settlePromiseNow(promise);
+
+// Don't assert when rejecting the promise.
+reject(0);

js/src/jit-test/tests/promise/settle-now-breaks-all-invariants-2.js

@@ -0,0 +1,27 @@
+// Test we don't assert when the promise is settled and the SpeciesConstructor
+// call in Promise.prototype.then throws an exception.
+
+function newPromiseCapability() {
+    var resolve, reject, promise = new Promise(function(r1, r2) {
+        resolve = r1;
+        reject = r2;
+    });
+    return {promise, resolve, reject};
+}
+
+
+var {promise, resolve} = newPromiseCapability();
+
+var p = Promise.resolve(0);
+
+p.constructor = {
+    [Symbol.species]: function() {
+        throw new Error();
+    }
+};
+
+// Enqueue a PromiseResolveThenableJob.
+resolve(p);
+
+// Settle the promise after the resolve call.
+settlePromiseNow(promise);

js/src/jit-test/tests/promise/settle-now-breaks-all-invariants-3.js

@@ -0,0 +1,27 @@
+// Test we don't assert when the promise is settled and the SpeciesConstructor
+// call in Promise.prototype.then throws an exception.
+
+function newPromiseCapability() {
+    var resolve, reject, promise = new Promise(function(r1, r2) {
+        resolve = r1;
+        reject = r2;
+    });
+    return {promise, resolve, reject};
+}
+
+
+var {promise, resolve} = newPromiseCapability();
+
+var p = Promise.resolve(0);
+
+p.constructor = {
+    [Symbol.species]: function() {
+        // Settle the promise in the SpeciesConstructor call.
+        settlePromiseNow(promise);
+
+        throw new Error();
+    }
+};
+
+// Enqueue a PromiseResolveThenableJob.
+resolve(p);

js/src/jit-test/tests/promise/settle-now-breaks-all-invariants-4.js

@@ -0,0 +1,18 @@
+// Test we don't assert when the promise is settled and we then try to call the
+// resolving function.
+
+function newPromiseCapability() {
+    var resolve, reject, promise = new Promise(function(r1, r2) {
+        resolve = r1;
+        reject = r2;
+    });
+    return {promise, resolve, reject};
+}
+
+
+var {promise, resolve} = newPromiseCapability();
+
+settlePromiseNow(promise);
+
+// Don't assert when the promise is already settled.
+resolve(0);

js/src/jit-test/tests/promise/settle-now-breaks-all-invariants-5.js

@@ -0,0 +1,18 @@
+// Test we don't assert when the promise is settled and we then try to call the
+// rejecting function.
+
+function newPromiseCapability() {
+    var resolve, reject, promise = new Promise(function(r1, r2) {
+        resolve = r1;
+        reject = r2;
+    });
+    return {promise, resolve, reject};
+}
+
+
+var {promise, reject} = newPromiseCapability();
+
+settlePromiseNow(promise);
+
+// Don't assert when the promise is already settled.
+reject(0);

js/src/jit-test/tests/promise/settle-now-breaks-all-invariants-6.js

@@ -0,0 +1,20 @@
+// Don't assert when a side-effect when getting the "then" property settled the promise.
+
+function newPromiseCapability() {
+    var resolve, reject, promise = new Promise(function(r1, r2) {
+        resolve = r1;
+        reject = r2;
+    });
+    return {promise, resolve, reject};
+}
+
+
+var {promise, resolve} = newPromiseCapability();
+
+var thenable = {
+    get then() {
+        settlePromiseNow(promise);
+    }
+};
+
+resolve(thenable);

js/src/jit-test/tests/promise/settle-now-breaks-all-invariants-7.js

@@ -0,0 +1,23 @@
+// Don't assert when a side-effect when getting the "then" property settled the promise.
+
+function newPromiseCapability() {
+    var resolve, reject, promise = new Promise(function(r1, r2) {
+        resolve = r1;
+        reject = r2;
+    });
+    return {promise, resolve, reject};
+}
+
+
+var {promise, resolve} = newPromiseCapability();
+
+var thenable = {
+    get then() {
+        settlePromiseNow(promise);
+
+        // Throw an error to reject the promise.
+        throw new Error();
+    }
+};
+
+resolve(thenable);

js/src/jit-test/tests/promise/settle-now-breaks-all-invariants-8.js

@@ -0,0 +1,7 @@
+// Don't assert when settlePromiseNow() is called on an async-function promise.
+
+var promise = async function(){ await 0; }();
+
+try {
+    settlePromiseNow(promise);
+} catch {}

js/src/jit-test/tests/promise/settle-now-breaks-all-invariants-9.js

@@ -0,0 +1,15 @@
+function newPromiseCapability() {
+    var resolve, reject, promise = new Promise(function(r1, r2) {
+        resolve = r1;
+        reject = r2;
+    });
+    return {promise, resolve, reject};
+}
+
+
+var {promise, resolve, reject} = newPromiseCapability();
+
+settlePromiseNow(promise);
+
+assertEq(resolve(0), undefined);
+assertEq(reject(0), undefined);

js/src/jit-test/tests/realms/promise-then.js

@@ -0,0 +1,30 @@
+load(libdir + "asserts.js");
+
+const g = newGlobal({sameCompartmentAs: this});
+
+let resolve, reject;
+let promise = new Promise((resolveFn, rejectFn) => {
+    resolve = resolveFn;
+    reject = rejectFn;
+});
+
+// Set to a built-in Promise.prototype.then function, but from a different realm.
+promise.then = g.Promise.prototype.then;
+
+// Make SpeciesConstructor throw a TypeError exception.
+promise.constructor = {
+    [Symbol.species]: "not a constructor"
+};
+
+async function f(p) {
+    await p;
+}
+
+let error;
+f(promise).catch(e => { error = e; });
+
+resolve(promise);
+
+drainJobQueue();
+
+assertEq(error.constructor === g.TypeError, true);

js/src/vm/Runtime.cpp

@@ -721,8 +721,8 @@ JSRuntime::enqueuePromiseJob(JSContext* cx, HandleFunction job, HandleObject pro
     if (promise) {
         RootedObject unwrappedPromise(cx, promise);
         // While the job object is guaranteed to be unwrapped, the promise
-        // might be wrapped. See the comments in
-        // intrinsic_EnqueuePromiseReactionJob for details.
+        // might be wrapped. See the comments in EnqueuePromiseReactionJob in
+        // builtin/Promise.cpp for details.
         if (IsWrapper(promise))
             unwrappedPromise = UncheckedUnwrap(promise);
         if (unwrappedPromise->is<PromiseObject>())