Revision: 3871
Author: [email protected]
Date: Tue Feb 16 04:14:23 2010
Log: Introduce builtin for Array.slice function.
Review URL: http://codereview.chromium.org/604059
http://code.google.com/p/v8/source/detail?r=3871
Added:
/branches/bleeding_edge/test/mjsunit/array-slice.js
Modified:
/branches/bleeding_edge/src/bootstrapper.cc
/branches/bleeding_edge/src/builtins.cc
/branches/bleeding_edge/src/builtins.h
/branches/bleeding_edge/src/execution.cc
/branches/bleeding_edge/src/ic.cc
=======================================
--- /dev/null
+++ /branches/bleeding_edge/test/mjsunit/array-slice.js Tue Feb 16 04:14:23
2010
@@ -0,0 +1,162 @@
+// Copyright 2010 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following
+// disclaimer in the documentation and/or other materials provided
+// with the distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived
+// from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+// Check that slicing array of holes keeps it as array of holes
+(function() {
+ var array = new Array(10);
+ for (var i = 0; i < 7; i++) {
+ var sliced = array.slice();
+ assertEquals(array.length, sliced.length);
+ assertFalse(0 in sliced);
+ }
+})();
+
+
+// Check various forms of arguments omission.
+(function() {
+ var array = new Array(7);
+
+ for (var i = 0; i < 7; i++) {
+ assertEquals(array, array.slice());
+ assertEquals(array, array.slice(0));
+ assertEquals(array, array.slice(undefined));
+ assertEquals(array, array.slice("foobar"));
+ assertEquals(array, array.slice(undefined, undefined));
+ }
+})();
+
+
+// Check variants of negatives and positive indices.
+(function() {
+ var array = new Array(7);
+
+ for (var i = 0; i < 7; i++) {
+ assertEquals(7, array.slice(-100).length);
+ assertEquals(3, array.slice(-3).length);
+ assertEquals(3, array.slice(4).length);
+ assertEquals(1, array.slice(6).length);
+ assertEquals(0, array.slice(7).length);
+ assertEquals(0, array.slice(8).length);
+ assertEquals(0, array.slice(100).length);
+
+ assertEquals(0, array.slice(0, -100).length);
+ assertEquals(4, array.slice(0, -3).length);
+ assertEquals(4, array.slice(0, 4).length);
+ assertEquals(6, array.slice(0, 6).length);
+ assertEquals(7, array.slice(0, 7).length);
+ assertEquals(7, array.slice(0, 8).length);
+ assertEquals(7, array.slice(0, 100).length);
+
+ // Some exotic cases.
+
+ obj = { toString: function() { throw 'Exception'; } };
+
+ // More than 2 arguments:
+ assertEquals(7, array.slice(0, 7, obj, null, undefined).length);
+
+ // Custom conversion:
+ assertEquals(1, array.slice({valueOf: function() { return 1; }},
+ {toString: function() { return 2;
}}).length);
+
+ // Throwing an exception in conversion:
+ try {
+ assertEquals(7, array.slice(0, obj).length);
+ throw 'Should have thrown';
+ } catch (e) {
+ assertEquals('Exception', e);
+ }
+ }
+})();
+
+
+// Nasty: modify the array in ToInteger.
+(function() {
+ var array = [];
+ var expected = []
+ bad_guy = { valueOf: function() { array.push(array.length); return -1; }
};
+
+ for (var i = 0; i < 13; i++) {
+ var sliced = array.slice(bad_guy);
+ expected.push(i);
+ assertEquals(expected, array);
+ // According to the spec (15.4.4.10), length is calculated before
+ // performing ToInteger on arguments.
+ if (i == 0) {
+ assertEquals([], sliced); // Length was 0, nothing to get.
+ } else {
+ // Actually out of array [0..i] we get [i - 1] as length is i.
+ assertEquals([i - 1], sliced);
+ }
+ }
+})();
+
+
+// Now check the case with array of holes and some elements on prototype.
+(function() {
+ var len = 9;
+ var array = new Array(len);
+
+ var at3 = "@3";
+ var at7 = "@7";
+
+ for (var i = 0; i < 7; i++) {
+ Array.prototype[3] = at3;
+ Array.prototype[7] = at7;
+
+ assertEquals(len, array.length);
+ for (var i = 0; i < array.length; i++) {
+ assertEquals(array[i], Array.prototype[i]);
+ }
+
+ var sliced = array.slice();
+
+ assertEquals(len, sliced.length);
+
+ assertTrue(delete Array.prototype[3]);
+ assertTrue(delete Array.prototype[7]);
+
+ // Note that slice copies values from prototype into the array.
+ assertEquals(array[3], undefined);
+ assertFalse(array.hasOwnProperty(3));
+ assertEquals(sliced[3], at3);
+ assertTrue(sliced.hasOwnProperty(3));
+
+ assertEquals(array[7], undefined);
+ assertFalse(array.hasOwnProperty(7));
+ assertEquals(sliced[7], at7);
+ assertTrue(sliced.hasOwnProperty(7));
+
+ // ... but keeps the rest as holes:
+ Array.prototype[5] = "@5";
+ assertEquals(array[5], Array.prototype[5]);
+ assertFalse(array.hasOwnProperty(5));
+ assertEquals(sliced[5], Array.prototype[5]);
+ assertFalse(sliced.hasOwnProperty(5));
+
+ assertTrue(delete Array.prototype[5]);
+ }
+})();
=======================================
--- /branches/bleeding_edge/src/bootstrapper.cc Tue Feb 16 01:24:14 2010
+++ /branches/bleeding_edge/src/bootstrapper.cc Tue Feb 16 04:14:23 2010
@@ -1495,6 +1495,8 @@
Handle<Code>(Builtins::builtin(Builtins::ArrayShift)));
AddSpecialFunction(special_prototype, "unshift",
Handle<Code>(Builtins::builtin(Builtins::ArrayUnshift)));
+ AddSpecialFunction(special_prototype, "slice",
+
Handle<Code>(Builtins::builtin(Builtins::ArraySlice)));
}
=======================================
--- /branches/bleeding_edge/src/builtins.cc Mon Feb 15 05:25:06 2010
+++ /branches/bleeding_edge/src/builtins.cc Tue Feb 16 04:14:23 2010
@@ -417,6 +417,110 @@
array->set_length(Smi::FromInt(new_length));
return Smi::FromInt(new_length);
}
+
+
+static Object* SlowArraySlice(Handle<Object> receiver,
+ Object** arg0,
+ Object** arg1 = NULL) {
+ HandleScope handleScope;
+
+ Handle<Object> slow_slice =
+ GetProperty(Handle<JSObject>(Top::global_context()->builtins()),
+ "ArraySlice");
+ ASSERT(slow_slice->IsJSFunction());
+ Handle<JSFunction> function(Handle<JSFunction>::cast(slow_slice));
+ Object** args[] = { arg0, arg1 };
+ bool pending_exception = false;
+ Handle<Object> result = Execution::Call(function,
+ receiver,
+ arg1 == NULL ? 1 : 2,
+ args,
+ &pending_exception);
+ if (pending_exception) return Failure::Exception();
+ return *result;
+}
+
+
+BUILTIN(ArraySlice) {
+ JSArray* array = JSArray::cast(*args.receiver());
+ ASSERT(array->HasFastElements());
+
+ int len = Smi::cast(array->length())->value();
+
+ int n_arguments = args.length() - 1;
+
+ // Note carefully choosen defaults---if argument is missing,
+ // it's undefined which gets converted to 0 for relativeStart
+ // and to len for relativeEnd.
+ int relativeStart = 0;
+ int relativeEnd = len;
+ if (n_arguments > 0) {
+ Object* arg1 = args[1];
+ if (arg1->IsSmi()) {
+ relativeStart = Smi::cast(arg1)->value();
+ } else if (!arg1->IsUndefined()) {
+ if (n_arguments > 1) {
+ return SlowArraySlice(args.receiver(), &args[1], &args[2]);
+ } else {
+ return SlowArraySlice(args.receiver(), &args[1]);
+ }
+ }
+ if (n_arguments > 1) {
+ Object* arg2 = args[2];
+ if (arg2->IsSmi()) {
+ relativeEnd = Smi::cast(arg2)->value();
+ } else if (!arg2->IsUndefined()) {
+ return SlowArraySlice(args.receiver(), &args[1], &args[2]);
+ }
+ }
+ }
+
+ // ECMAScript 232, 3rd Edition, Section 15.4.4.10, step 6.
+ int k = (relativeStart < 0) ? Max(len + relativeStart, 0)
+ : Min(relativeStart, len);
+
+ // ECMAScript 232, 3rd Edition, Section 15.4.4.10, step 8.
+ int final = (relativeEnd < 0) ? Max(len + relativeEnd, 0)
+ : Min(relativeEnd, len);
+
+ // Calculate the length of result array.
+ int result_len = final - k;
+ if (result_len < 0) {
+ result_len = 0;
+ }
+
+ JSFunction* array_function =
+ Top::context()->global_context()->array_function();
+ Object* result = Heap::AllocateJSObject(array_function);
+ if (result->IsFailure()) return result;
+ JSArray* result_array = JSArray::cast(result);
+
+ result = Heap::AllocateFixedArrayWithHoles(result_len);
+ if (result->IsFailure()) return result;
+ FixedArray* result_elms = FixedArray::cast(result);
+
+ FixedArray* elms = FixedArray::cast(array->elements());
+
+ // Fetch the prototype.
+ JSObject* prototype = JSObject::cast(array_function->prototype());
+
+ AssertNoAllocation no_gc;
+ WriteBarrierMode mode = result_elms->GetWriteBarrierMode(no_gc);
+
+ // Fill newly created array.
+ for (int i = 0; i < result_len; i++) {
+ result_elms->set(i,
+ GetElementToMove(k + i, elms, prototype),
+ mode);
+ }
+
+ // Set elements.
+ result_array->set_elements(result_elms);
+
+ // Set the length.
+ result_array->set_length(Smi::FromInt(result_len));
+ return result_array;
+}
//
-----------------------------------------------------------------------------
=======================================
--- /branches/bleeding_edge/src/builtins.h Mon Feb 15 05:25:06 2010
+++ /branches/bleeding_edge/src/builtins.h Tue Feb 16 04:14:23 2010
@@ -50,6 +50,7 @@
V(ArrayPop, NO_EXTRA_ARGUMENTS) \
V(ArrayShift, NO_EXTRA_ARGUMENTS) \
V(ArrayUnshift, NO_EXTRA_ARGUMENTS) \
+ V(ArraySlice, NO_EXTRA_ARGUMENTS) \
\
V(HandleApiCall, NEEDS_CALLED_FUNCTION) \
V(FastHandleApiCall, NO_EXTRA_ARGUMENTS) \
=======================================
--- /branches/bleeding_edge/src/execution.cc Fri Jan 15 13:14:56 2010
+++ /branches/bleeding_edge/src/execution.cc Tue Feb 16 04:14:23 2010
@@ -91,7 +91,7 @@
JSEntryFunction entry = FUNCTION_CAST<JSEntryFunction>(code->entry());
// Call the function through the right JS entry stub.
- byte* entry_address= func->code()->entry();
+ byte* entry_address = func->code()->entry();
JSFunction* function = *func;
Object* receiver_pointer = *receiver;
value = CALL_GENERATED_CODE(entry, entry_address, function,
=======================================
--- /branches/bleeding_edge/src/ic.cc Fri Feb 12 06:21:18 2010
+++ /branches/bleeding_edge/src/ic.cc Tue Feb 16 04:14:23 2010
@@ -455,7 +455,7 @@
if (result->IsJSFunction()) {
// Check if there is an optimized (builtin) version of the function.
- // Ignored this will degrade performance for
Array.prototype.{push,pop}.
+ // Ignored this will degrade performance for some Array functions.
// Please note we only return the optimized function iff
// the JSObject has FastElements.
if (object->IsJSObject() &&
JSObject::cast(*object)->HasFastElements()) {
--
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