Reviewers: Yang,
Message:
PTAL. That's the end of low-hanging fruit in typed array constructors +
preparations to more hydrogenizing.
Description:
Speed up typed array constructors.
- Avoid calls into ToPositiveInteger for valid cases of 'undefined'
arguments.
(Otherwise it calls into runtime).
- Reduce the checks performed in case offset for TypedArrayFromArrayBuffer
constructor is called with no offset argument.
Please review this at https://codereview.chromium.org/59763010/
SVN Base: https://v8.googlecode.com/svn/branches/bleeding_edge
Affected files (+17, -10 lines):
M src/typedarray.js
Index: src/typedarray.js
diff --git a/src/typedarray.js b/src/typedarray.js
index
20a50c5c1bcfa43c747e1d9cb59bd4eca8f643be..d435803a5aa603793c5cce5ada2bd884979f0a24
100644
--- a/src/typedarray.js
+++ b/src/typedarray.js
@@ -49,15 +49,20 @@ endmacro
macro TYPED_ARRAY_CONSTRUCTOR(ARRAY_ID, NAME, ELEMENT_SIZE)
function NAMEConstructByArrayBuffer(obj, buffer, byteOffset, length) {
- var offset =
ToPositiveInteger(byteOffset, "invalid_typed_array_length")
-
- if (offset % ELEMENT_SIZE !== 0) {
- throw MakeRangeError("invalid_typed_array_alignment",
- "start offset", "NAME", ELEMENT_SIZE);
- }
var bufferByteLength = buffer.byteLength;
- if (offset > bufferByteLength) {
- throw MakeRangeError("invalid_typed_array_offset");
+ var offset;
+ if (IS_UNDEFINED(byteOffset)) {
+ offset = 0;
+ } else {
+ offset = ToPositiveInteger(byteOffset, "invalid_typed_array_length");
+
+ if (offset % ELEMENT_SIZE !== 0) {
+ throw MakeRangeError("invalid_typed_array_alignment",
+ "start offset", "NAME", ELEMENT_SIZE);
+ }
+ if (offset > bufferByteLength) {
+ throw MakeRangeError("invalid_typed_array_offset");
+ }
}
var newByteLength;
@@ -80,7 +85,8 @@ macro TYPED_ARRAY_CONSTRUCTOR(ARRAY_ID, NAME,
ELEMENT_SIZE)
}
function NAMEConstructByLength(obj, length) {
- var l = ToPositiveInteger(length, "invalid_typed_array_length");
+ var l = IS_UNDEFINED(length) ?
+ 0 : ToPositiveInteger(length, "invalid_typed_array_length");
var byteLength = l * ELEMENT_SIZE;
var buffer = new $ArrayBuffer(byteLength);
%TypedArrayInitialize(obj, ARRAY_ID, buffer, 0, byteLength);
@@ -301,7 +307,8 @@ function DataViewConstructor(buffer, byteOffset,
byteLength) { // length = 3
throw MakeTypeError('data_view_not_array_buffer', []);
}
var bufferByteLength = %ArrayBufferGetByteLength(buffer);
- var offset = ToPositiveInteger(byteOffset, 'invalid_data_view_offset');
+ var offset = IS_UNDEFINED(byteOffset) ?
+ 0 : ToPositiveInteger(byteOffset, 'invalid_data_view_offset');
if (offset > bufferByteLength) {
throw MakeRangeError('invalid_data_view_offset');
}
--
--
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