Changeset 205267 in webkit

Timestamp:

Aug 31, 2016 2:03:34 PM (8 years ago)

Author:

Yusuke Suzuki

Message:

stress/random-53bit.js.ftl-no-cjit-no-inline-validate sometimes fails
​https://bugs.webkit.org/show_bug.cgi?id=161436

Reviewed by Filip Pizlo.

JSTests:

The test checks Math.random() correctly produces 53bit random values.
The test can fail by design, but this should be fairly rare.

However, when introducing, we wrap the test() with 1e4 to ensure the FTL compilation, and this
increases the failure rate. By increasing the MAX in the test, we make the failures much more rare case.

And we also add getRandomSeed() and setRandomSeed(seed) JSC shell helpers to dump more useful information
and reproduce the situation easily.

• stress/random-53bit.js:

(test):

Source/JavaScriptCore:

• jsc.cpp:

(GlobalObject::finishCreation):
(functionGetRandomSeed):
(functionSetRandomSeed):

• runtime/JSGlobalObject.h:

(JSC::JSGlobalObject::weakRandom):
(JSC::JSGlobalObject::weakRandomInteger): Deleted.

Location:

trunk

Files:

• JSTests/ChangeLog (modified) (1 diff)
• JSTests/stress/random-53bit.js (modified) (2 diffs)
• Source/JavaScriptCore/ChangeLog (modified) (1 diff)
• Source/JavaScriptCore/jsc.cpp (modified) (3 diffs)
• Source/JavaScriptCore/runtime/JSGlobalObject.h (modified) (1 diff)

trunk/JSTests/ChangeLog

@@ +1 @@
+2016-08-31  Yusuke Suzuki  <utatane.tea@gmail.com>
+
+        stress/random-53bit.js.ftl-no-cjit-no-inline-validate sometimes fails
+        https://bugs.webkit.org/show_bug.cgi?id=161436
+
+        Reviewed by Filip Pizlo.
+
+        The test checks Math.random() correctly produces 53bit random values.
+        The test can fail by design, but this should be fairly rare.
+
+        However, when introducing, we wrap the `test()` with 1e4 to ensure the FTL compilation, and this
+        increases the failure rate. By increasing the MAX in the test, we make the failures much more rare case.
+
+        And we also add getRandomSeed() and setRandomSeed(seed) JSC shell helpers to dump more useful information
+        and reproduce the situation easily.
+
+        * stress/random-53bit.js:
+        (test):
+
 2016-08-29  Benjamin Poulain  <bpoulain@apple.com>
 

trunk/JSTests/stress/random-53bit.js

@@ -1 +1 @@
 function test() {
-    var MAX = 30;
+    var MAX = 50;
     var found53Bit = false;
     var foundLessThan53Bit = false;
+    var results = new Array(MAX);
 
     for (var i = 0; i < MAX; ++i) {
         var str = Math.random().toString(2);
+        results[i] = str;
         // 53 bit + '0.'.length
         if (str.length === (53 + 2))
@@ -15 +17 @@
             return true;
     }
+    print(`Random seed ${getRandomSeed()}`);
+    print(results.join('\n'));
     return false;
 }

trunk/Source/JavaScriptCore/ChangeLog

@@ +1 @@
+2016-08-31  Yusuke Suzuki  <utatane.tea@gmail.com>
+
+        stress/random-53bit.js.ftl-no-cjit-no-inline-validate sometimes fails
+        https://bugs.webkit.org/show_bug.cgi?id=161436
+
+        Reviewed by Filip Pizlo.
+
+        * jsc.cpp:
+        (GlobalObject::finishCreation):
+        (functionGetRandomSeed):
+        (functionSetRandomSeed):
+        * runtime/JSGlobalObject.h:
+        (JSC::JSGlobalObject::weakRandom):
+        (JSC::JSGlobalObject::weakRandomInteger): Deleted.
+
 2016-08-31  Chris Dumez  <cdumez@apple.com>
 

trunk/Source/JavaScriptCore/jsc.cpp

@@ -648 +648 @@
 static EncodedJSValue JSC_HOST_CALL functionShadowChickenFunctionsOnStack(ExecState*);
 static EncodedJSValue JSC_HOST_CALL functionSetGlobalConstRedeclarationShouldNotThrow(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionGetRandomSeed(ExecState*);
+static EncodedJSValue JSC_HOST_CALL functionSetRandomSeed(ExecState*);
 
 struct Script {
@@ -857 +859 @@
 
         addFunction(vm, "drainMicrotasks", functionDrainMicrotasks, 0);
+
+        addFunction(vm, "getRandomSeed", functionGetRandomSeed, 0);
+        addFunction(vm, "setRandomSeed", functionSetRandomSeed, 1);
 
         addFunction(vm, "is32BitPlatform", functionIs32BitPlatform, 0);
@@ -1598 +1603 @@
 }
 
+EncodedJSValue JSC_HOST_CALL functionGetRandomSeed(ExecState* exec)
+{
+    return JSValue::encode(jsNumber(exec->lexicalGlobalObject()->weakRandom().seed()));
+}
+
+EncodedJSValue JSC_HOST_CALL functionSetRandomSeed(ExecState* exec)
+{
+    unsigned seed = exec->argument(0).toUInt32(exec);
+    if (exec->hadException())
+        return JSValue::encode(jsUndefined());
+    exec->lexicalGlobalObject()->weakRandom().setSeed(seed);
+    return JSValue::encode(jsUndefined());
+}
+
 EncodedJSValue JSC_HOST_CALL functionReadline(ExecState* exec)
 {

trunk/Source/JavaScriptCore/runtime/JSGlobalObject.h

@@ -767 +767 @@
     double weakRandomNumber() { return m_weakRandom.get(); }
     unsigned weakRandomInteger() { return m_weakRandom.getUint32(); }
+    WeakRandom& weakRandom() { return m_weakRandom; }
 
     UnlinkedProgramCodeBlock* createProgramCodeBlock(CallFrame*, ProgramExecutable*, JSObject** exception);