Bug 772722 - Remove superfluous usage of Atomics in SpiderMonkey; r=luke

None of the current usages of ATOMIC_INC/DEC are useful now that we do not allow
multi-threaded runtimes. This also removes a pre-mature optimization that
happened to be using the atomics. I measured it as saving strictly < 3us on old
hardware.

--HG--
extra : rebase_source : 83ff1826f4cfb59fa505ae2e7a7150c4a478598b

js/src/builtin/TestingFunctions.cpp

@@ -650,7 +650,7 @@ static unsigned finalizeCount = 0;
 static void
 finalize_counter_finalize(JSFreeOp *fop, JSObject *obj)
 {
-    JS_ATOMIC_INCREMENT(&finalizeCount);
+    ++finalizeCount;
 }
 
 static JSClass FinalizeCounterClass = {

js/src/jscntxt.cpp

@@ -656,8 +656,9 @@ js_ReportOutOfMemory(JSContext *cx)
      */
     cx->clearPendingException();
     if (onError) {
-        AutoAtomicIncrement incr(&cx->runtime->inOOMReport);
+        ++cx->runtime->inOOMReport;
         onError(cx, msg, &report);
+        --cx->runtime->inOOMReport;
     }
 }
 

js/src/jscntxt.h

@@ -867,7 +867,7 @@ struct JSRuntime : js::RuntimeFriendFields
      * and for each JSObject::remove method call that frees a slot in the given
      * object. See js_NativeGet and js_NativeSet in jsobj.cpp.
      */
-    int32_t             propertyRemovals;
+    uint32_t            propertyRemovals;
 
     /* Number localization, used by jsnum.c */
     const char          *thousandsSeparator;

js/src/jslock.h

@@ -38,25 +38,4 @@ typedef struct PRLock PRLock;
 
 #endif /* JS_THREADSAFE */
 
-namespace js {
-
-class AutoAtomicIncrement
-{
-    int32_t *p;
-    JS_DECL_USE_GUARD_OBJECT_NOTIFIER
-
-  public:
-    AutoAtomicIncrement(int32_t *p JS_GUARD_OBJECT_NOTIFIER_PARAM)
-      : p(p) {
-        JS_GUARD_OBJECT_NOTIFIER_INIT;
-        JS_ATOMIC_INCREMENT(p);
-    }
-
-    ~AutoAtomicIncrement() {
-        JS_ATOMIC_DECREMENT(p);
-    }
-};
-
-}  /* namespace js */
-
 #endif /* jslock_h___ */

js/src/jsscope.cpp

@@ -726,7 +726,7 @@ JSObject::putProperty(JSContext *cx, jsid id_,
     if (hadSlot && !shape->hasSlot()) {
         if (oldSlot < self->slotSpan())
             self->freeSlot(oldSlot);
-        JS_ATOMIC_INCREMENT(&cx->runtime->propertyRemovals);
+        ++cx->runtime->propertyRemovals;
     }
 
     self->checkShapeConsistency();
@@ -829,7 +829,7 @@ JSObject::removeProperty(JSContext *cx, jsid id_)
     /* If shape has a slot, free its slot number. */
     if (shape->hasSlot()) {
         self->freeSlot(shape->slot());
-        JS_ATOMIC_INCREMENT(&cx->runtime->propertyRemovals);
+        ++cx->runtime->propertyRemovals;
     }
 
     /*
@@ -906,7 +906,7 @@ JSObject::clear(JSContext *cx, HandleObject obj)
 
     JS_ALWAYS_TRUE(JSObject::setLastProperty(cx, obj, shape));
 
-    JS_ATOMIC_INCREMENT(&cx->runtime->propertyRemovals);
+    ++cx->runtime->propertyRemovals;
     obj->checkShapeConsistency();
 }
 

js/src/prmjtime.cpp

@@ -326,11 +326,6 @@ def PRMJ_Now():
 
 */
 
-// We parameterize the delay count just so that shell builds can
-// set it to 0 in order to get high-resolution benchmarking.
-// 10 seems to be the number of calls to load with a blank homepage.
-int CALIBRATION_DELAY_COUNT = 10;
-
 int64_t
 PRMJ_Now(void)
 {
@@ -343,16 +338,6 @@ PRMJ_Now(void)
     int64_t returnedTime;
     long double cachedOffset = 0.0;
 
-    /* To avoid regressing startup time (where high resolution is likely
-       not needed), give the old behavior for the first few calls.
-       This does not appear to be needed on Vista as the timeBegin/timeEndPeriod
-       calls seem to immediately take effect. */
-    int thiscall = JS_ATOMIC_INCREMENT(&nCalls);
-    if (thiscall <= CALIBRATION_DELAY_COUNT) {
-        GetSystemTimeAsFileTime(&ft);
-        return (FILETIME2INT64(ft)-win2un)/10L;
-    }
-
     /* For non threadsafe platforms, NowInit is not necessary */
 #ifdef JS_THREADSAFE
     PR_CallOnce(&calibrationOnce, NowInit);

js/src/shell/js.cpp

@@ -4923,13 +4923,6 @@ main(int argc, char **argv, char **envp)
         OOM_printAllocationCount = true;
 #endif
 
-#ifdef XP_WIN
-    // Set the timer calibration delay count to 0 so we get high
-    // resolution right away, which we need for precise benchmarking.
-    extern int CALIBRATION_DELAY_COUNT;
-    CALIBRATION_DELAY_COUNT = 0;
-#endif
-
     /* Use the same parameters as the browser in xpcjsruntime.cpp. */
     rt = JS_NewRuntime(32L * 1024L * 1024L, JS_USE_HELPER_THREADS);
     if (!rt)