Bug 456165. Trace |new Date()|. r=brendan

js/src/builtins.tbl

@@ -141,6 +141,7 @@ BUILTIN1(Arguments,             LO,     P,      JSObject*, JSContext*, 0, 0)
 
 // Don't really need an argument here, but we don't support arg-less builtins
 BUILTIN1(Date_now,              LO,     F,      jsdouble, JSContext*, 0, 0)
+BUILTIN2(FastNewDate,           LO, LO, P,      JSObject*, JSContext*, JSObject*, 0, 0)
 
 // soft float
 BUILTIN1(fneg,   F,       F,  jsdouble, jsdouble, 1, 1)

js/src/jsbuiltins.cpp

@@ -52,6 +52,7 @@
 #include "jsmath.h"
 #include "jsnum.h"
 #include "prmjtime.h"
+#include "jsdate.h"
 #include "jsscope.h"
 #include "jsstr.h"
 #include "jstracer.h"
@@ -875,6 +876,37 @@ js_Date_now(JSContext*)
     return PRMJ_Now() / PRMJ_USEC_PER_MSEC;
 }
 
+JS_STATIC_ASSERT(JSSLOT_PRIVATE == JSSLOT_UTC_TIME);
+JS_STATIC_ASSERT(JSSLOT_UTC_TIME + 1 == JSSLOT_LOCAL_TIME);
+
+JSObject* FASTCALL
+js_FastNewDate(JSContext* cx, JSObject* proto)
+{
+    JS_ASSERT(JS_ON_TRACE(cx));
+    JSObject* obj = (JSObject*) js_NewGCThing(cx, GCX_OBJECT, sizeof(JSObject));
+    if (!obj)
+        return NULL;
+
+    JSClass* clasp = &js_DateClass;
+    obj->classword = jsuword(clasp);
+
+    obj->fslots[JSSLOT_PROTO] = OBJECT_TO_JSVAL(proto);
+    obj->fslots[JSSLOT_PARENT] = proto->fslots[JSSLOT_PARENT];
+
+    jsdouble* date = js_NewWeaklyRootedDouble(cx, 0.0);
+    if (!date)
+        return NULL;
+    *date = js_Date_now(cx);
+    obj->fslots[JSSLOT_UTC_TIME] = DOUBLE_TO_JSVAL(date);
+    obj->fslots[JSSLOT_LOCAL_TIME] = DOUBLE_TO_JSVAL(cx->runtime->jsNaN);;
+
+    JS_ASSERT(!clasp->getObjectOps);
+    JS_ASSERT(proto->map->ops == &js_ObjectOps);
+    obj->map = js_HoldObjectMap(cx, proto->map);
+    obj->dslots = NULL;
+    return obj;    
+}
+
 /* soft float */
 
 jsdouble FASTCALL

js/src/jsdate.cpp

@@ -478,9 +478,6 @@ msFromTime(jsdouble t)
  * We use the first reseved slot to store UTC time, and the second for caching
  * the local time. The initial value of the cache entry is NaN.
  */
-const uint32 JSSLOT_UTC_TIME    = JSSLOT_PRIVATE;
-const uint32 JSSLOT_LOCAL_TIME  = JSSLOT_PRIVATE + 1;
-
 const uint32 DATE_RESERVED_SLOTS = 2;
 
 JSClass js_DateClass = {
@@ -2027,8 +2024,8 @@ date_constructor(JSContext *cx, JSObject* obj)
     return date;
 }
 
-static JSBool
-Date(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
+JSBool
+js_Date(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval)
 {
     jsdouble *date;
     JSString *str;
@@ -2099,7 +2096,7 @@ js_InitDateClass(JSContext *cx, JSObject *obj)
 
     /* set static LocalTZA */
     LocalTZA = -(PRMJ_LocalGMTDifference() * msPerSecond);
-    proto = JS_InitClass(cx, obj, NULL, &js_DateClass, Date, MAXARGS,
+    proto = JS_InitClass(cx, obj, NULL, &js_DateClass, js_Date, MAXARGS,
                          NULL, date_methods, NULL, date_static_methods);
     if (!proto)
         return NULL;

js/src/jsdate.h

@@ -54,6 +54,15 @@ js_InitDateClass(JSContext *cx, JSObject *obj);
 extern JSBool
 js_date_now(JSContext *cx, uintN argc, jsval *vp);
 
+extern JSClass js_DateClass;
+
+/*
+ * We use the first reseved slot to store UTC time, and the second for caching
+ * the local time. The initial value of the cache entry is NaN.
+ */
+#define JSSLOT_UTC_TIME    JSSLOT_PRIVATE
+#define JSSLOT_LOCAL_TIME  (JSSLOT_PRIVATE + 1)
+
 /*
  * These functions provide a C interface to the date/time object
  */

js/src/jstracer.cpp

@@ -4359,6 +4359,9 @@ js_Array(JSContext* cx, JSObject* obj, uintN argc, jsval* argv, jsval* rval);
 JSBool
 js_Object(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval);
 
+JSBool
+js_Date(JSContext *cx, JSObject *obj, uintN argc, jsval *argv, jsval *rval);
+
 bool
 TraceRecorder::record_JSOP_NEW()
 {
@@ -4401,6 +4404,7 @@ TraceRecorder::record_JSOP_NEW()
         { (JSFastNative)js_Array,  F_Array_2obj,    "pC", "oo",  FAIL_NULL },
         { (JSFastNative)js_Array,  F_Array_3num,    "pC", "ddd", FAIL_NULL },
         { (JSFastNative)js_Object, F_FastNewObject, "fC", "",    FAIL_NULL },
+        { (JSFastNative)js_Date,   F_FastNewDate,   "pC", "",    FAIL_NULL },
     };
 
     for (uintN i = 0; i < JS_ARRAY_LENGTH(knownNatives); i++) {

js/src/trace-test.js

@@ -2026,6 +2026,26 @@ this.__proto__.a = 3; for (var j = 0; j < 4; ++j) { [a]; }
 testGlobalProtoAccess.expected = "ok";
 test(testGlobalProtoAccess);
 
+function testNewDate()
+{
+    // Accessing global.Date for the first time will change the global shape,
+    // so do it before the loop starts; otherwise we have to loop an extra time
+    // to pick things up.
+    var start = new Date();
+    var time = new Date();
+    for (var j = 0; j < RUNLOOP; ++j) {
+	time = new Date();
+    }
+    return time > 0 && time >= start;
+}
+testNewDate.expected = true;
+testNewDate.jitstats = {
+    recorderStarted: 1,
+    recorderAborted: 0,
+    traceTriggered: 1
+};
+test(testNewDate);
+
 /* Keep these at the end so that we can see the summary after the trace-debug spew. */
 print("\npassed:", passes.length && passes.join(","));
 print("\nFAILED:", fails.length && fails.join(","));