Bug 1548908: Clean up JS::CanonicalizedDoubleValue r=tcampbell

1. CanonicalizedDoubleValue should reuse the logic in CanonicalizeNaN.
2. Places that call DoubleValue(CanonicalizeNaN(d)) should just use CanonicalizedDoubleValue(d).

Differential Revision: https://phabricator.services.mozilla.com/D29867

--HG--
extra : moz-landing-system : lando

js/public/Date.h

@@ -114,7 +114,7 @@ inline ClippedTime TimeClip(double time) {
 // Produce a double Value from the given time.  Because times may be NaN,
 // prefer using this to manual canonicalization.
 inline Value TimeValue(ClippedTime time) {
-  return DoubleValue(CanonicalizeNaN(time.toDouble()));
+  return CanonicalizedDoubleValue(time.toDouble());
 }
 
 // Create a new Date object whose [[DateValue]] internal slot contains the

js/public/Value.h

@@ -1030,19 +1030,8 @@ static inline Value DoubleValue(double dbl) {
   return v;
 }
 
-static constexpr Value CanonicalNaNValue() {
-  uint64_t rawBits = detail::CanonicalizedNaNBits;
-#if defined(JS_PUNBOX64)
-  rawBits += JSVAL_PUN64_DOUBLE_ADJUST;
-#endif
-  return Value::fromRawBits(rawBits);
-}
-
 static inline Value CanonicalizedDoubleValue(double d) {
-  if (MOZ_UNLIKELY(mozilla::IsNaN(d))) {
-    return CanonicalNaNValue();
-  }
-  return Value::fromDouble(d);
+  return Value::fromDouble(CanonicalizeNaN(d));
 }
 
 static inline bool IsCanonicalized(double d) {

js/src/builtin/MapObject.cpp

@@ -46,13 +46,12 @@ bool HashableValue::setValue(JSContext* cx, HandleValue v) {
     int32_t i;
     if (NumberEqualsInt32(d, &i)) {
       // Normalize int32_t-valued doubles to int32_t for faster hashing and
-      // testing.
+      // testing. Note: we use NumberEqualsInt32 here instead of NumberIsInt32
+      // because we want -0 and 0 to be normalized to the same thing.
       value = Int32Value(i);
-    } else if (IsNaN(d)) {
-      // NaNs with different bits must hash and test identically.
-      value = DoubleNaNValue();
     } else {
-      value = v;
+      // Normalize the sign bit of a NaN.
+      value = JS::CanonicalizedDoubleValue(d);
     }
   } else {
     value = v;

js/src/vm/TypedArrayObject.cpp

@@ -1977,7 +1977,7 @@ bool TypedArrayObjectTemplate<float>::getElementPure(TypedArrayObject* tarray,
    * This could be removed for platforms/compilers known to convert a 32-bit
    * non-canonical nan to a 64-bit canonical nan.
    */
-  *vp = DoubleValue(CanonicalizeNaN(dval));
+  *vp = JS::CanonicalizedDoubleValue(dval);
   return true;
 }
 
@@ -1994,7 +1994,7 @@ bool TypedArrayObjectTemplate<double>::getElementPure(TypedArrayObject* tarray,
    * confuse the engine into interpreting a double-typed jsval as an
    * object-typed jsval.
    */
-  *vp = DoubleValue(CanonicalizeNaN(val));
+  *vp = JS::CanonicalizedDoubleValue(val);
   return true;
 }
 

js/src/wasm/WasmJS.cpp

@@ -208,9 +208,9 @@ static Value ToJSValue(const Val& val) {
     case ValType::I32:
       return Int32Value(val.i32());
     case ValType::F32:
-      return DoubleValue(JS::CanonicalizeNaN(double(val.f32())));
+      return JS::CanonicalizedDoubleValue(double(val.f32()));
     case ValType::F64:
-      return DoubleValue(JS::CanonicalizeNaN(val.f64()));
+      return JS::CanonicalizedDoubleValue(val.f64());
     case ValType::FuncRef:
     case ValType::AnyRef:
       return UnboxAnyRef(val.ref());