FloatTypedArrayAdaptor::toJSValue should almost certainly not use jsNumber() since...

FloatTypedArrayAdaptor::toJSValue should almost certainly not use jsNumber() since that attempts int conversions
https://bugs.webkit.org/show_bug.cgi?id=120228

Source/JavaScriptCore:

Reviewed by Oliver Hunt.

It turns out that there were three problems:

- Using jsNumber() meant that we were converting doubles to integers and then
  possibly back again whenever doing a set() between floating point arrays.

- Slow-path accesses to double typed arrays were slower than necessary because
  of the to-int conversion attempt.

- The use of JSValue as an intermediate for converting between differen types
  in typedArray.set() resulted in worse code than I had previously expected.

This patch solves the problem by using template double-dispatch to ensure that
that C++ compiler sees the simplest possible combination of casts between any
combination of typed array types, while still preserving JS and typed array
conversion semantics. Conversions are done as follows:

    SourceAdaptor::convertTo<TargetAdaptor>(value)

Internally, convertTo() calls one of three possible methods on TargetAdaptor,
with one method for each of int32_t, uint32_t, and double. This means that the
C++ compiler will at worst see a widening cast to one of those types followed
by a narrowing conversion (not necessarily a cast - may have clamping or the
JS toInt32() function).

This change doesn't just affect typedArray.set(); it also affects slow-path
accesses to typed arrays as well. This patch also adds a bunch of new test
coverage.

This change is a ~50% speed-up on typedArray.set() involving floating point
types.

* GNUmakefile.list.am:
* JavaScriptCore.vcxproj/JavaScriptCore.vcxproj:
* JavaScriptCore.xcodeproj/project.pbxproj:
* runtime/GenericTypedArrayView.h:
(JSC::GenericTypedArrayView::set):
* runtime/JSDataViewPrototype.cpp:
(JSC::setData):
* runtime/JSGenericTypedArrayView.h:
(JSC::JSGenericTypedArrayView::setIndexQuicklyToDouble):
(JSC::JSGenericTypedArrayView::setIndexQuickly):
* runtime/JSGenericTypedArrayViewInlines.h:
(JSC::::setWithSpecificType):
(JSC::::set):
* runtime/ToNativeFromValue.h: Added.
(JSC::toNativeFromValue):
* runtime/TypedArrayAdaptors.h:
(JSC::IntegralTypedArrayAdaptor::toJSValue):
(JSC::IntegralTypedArrayAdaptor::toDouble):
(JSC::IntegralTypedArrayAdaptor::toNativeFromInt32):
(JSC::IntegralTypedArrayAdaptor::toNativeFromUint32):
(JSC::IntegralTypedArrayAdaptor::toNativeFromDouble):
(JSC::IntegralTypedArrayAdaptor::convertTo):
(JSC::FloatTypedArrayAdaptor::toJSValue):
(JSC::FloatTypedArrayAdaptor::toDouble):
(JSC::FloatTypedArrayAdaptor::toNativeFromInt32):
(JSC::FloatTypedArrayAdaptor::toNativeFromUint32):
(JSC::FloatTypedArrayAdaptor::toNativeFromDouble):
(JSC::FloatTypedArrayAdaptor::convertTo):
(JSC::Uint8ClampedAdaptor::toJSValue):
(JSC::Uint8ClampedAdaptor::toDouble):
(JSC::Uint8ClampedAdaptor::toNativeFromInt32):
(JSC::Uint8ClampedAdaptor::toNativeFromUint32):
(JSC::Uint8ClampedAdaptor::toNativeFromDouble):
(JSC::Uint8ClampedAdaptor::convertTo):

LayoutTests:

Reviewed by Oliver Hunt.

Add coverage for three things:

- Typed array accesses with corner-case values.

- Typed array set() (i.e. copy) between arrays of different types.

- Performance of typedArray.set() involving different types.

This required some changes to our test harnesses, since they previously
couldn't consistently do numerical array comparisons in a reliable way.

* fast/js/regress/Float32Array-to-Float64Array-set-expected.txt: Added.
* fast/js/regress/Float32Array-to-Float64Array-set.html: Added.
* fast/js/regress/Float64Array-to-Int16Array-set-expected.txt: Added.
* fast/js/regress/Float64Array-to-Int16Array-set.html: Added.
* fast/js/regress/Int16Array-to-Int32Array-set-expected.txt: Added.
* fast/js/regress/Int16Array-to-Int32Array-set.html: Added.
* fast/js/regress/script-tests/Float32Array-to-Float64Array-set.js: Added.
* fast/js/regress/script-tests/Float64Array-to-Int16Array-set.js: Added.
* fast/js/regress/script-tests/Int16Array-to-Int32Array-set.js: Added.
* fast/js/resources/js-test-pre.js:
(areNumbersEqual):
(areArraysEqual):
(isResultCorrect):
* fast/js/resources/standalone-pre.js:
(areNumbersEqual):
(areArraysEqual):
(isTypedArray):
(isResultCorrect):
(stringify):
(shouldBe):
* fast/js/script-tests/typed-array-access.js: Added.
(bitsToString):
(bitsToValue):
(valueToBits):
(roundTrip):
* fast/js/script-tests/typed-array-set-different-types.js: Added.
(MyRandom):
(.reference):
(.usingConstruct):
* fast/js/typed-array-access-expected.txt: Added.
* fast/js/typed-array-access.html: Added.
* fast/js/typed-array-set-different-types-expected.txt: Added.
* fast/js/typed-array-set-different-types.html: Added.

git-svn-id: https://svn.webkit.org/repository/webkit/trunk@154569 268f45cc-cd09-0410-ab3c-d52691b4dbfc