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Fix polymorphic load on named fields.

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This fixes polymorphic loads to correctly compare in-object offsets
instead of indices, because indices might coincide even though the
actual slot is different because of different instance sizes.

R=danno@chromium.org
BUG=v8:2030
TEST=mjsunit/regress/regress-2030,mjsunit/mirror-array

Review URL: https://chromiumcodereview.appspot.com/9864028

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@11153 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
This commit is contained in:
mstarzinger@chromium.org 2012-03-27 10:42:38 +00:00
parent a071b4e04b
commit 057371da13
2 changed files with 68 additions and 3 deletions
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18
src/hydrogen.cc
View File

@ -4029,7 +4029,8 @@ void HGraphBuilder::HandlePolymorphicLoadNamedField(Property* expr,
SmallMapList* types,
Handle<String> name) {
int count = 0;
int previous_field_index = 0;
int previous_field_offset = 0;
bool previous_field_is_in_object = false;
bool is_monomorphic_field = true;
Handle<Map> map;
LookupResult lookup(isolate());
@ -4037,10 +4038,21 @@ void HGraphBuilder::HandlePolymorphicLoadNamedField(Property* expr,
map = types->at(i);
if (ComputeLoadStoreField(map, name, &lookup, false)) {
int index = ComputeLoadStoreFieldIndex(map, name, &lookup);
bool is_in_object = index < 0;
int offset = index * kPointerSize;
if (index < 0) {
// Negative property indices are in-object properties, indexed
// from the end of the fixed part of the object.
offset += map->instance_size();
} else {
offset += FixedArray::kHeaderSize;
}
if (count == 0) {
previous_field_index = index;
previous_field_offset = offset;
previous_field_is_in_object = is_in_object;
} else if (is_monomorphic_field) {
is_monomorphic_field = (index == previous_field_index);
is_monomorphic_field = (offset == previous_field_offset) &&
(is_in_object == previous_field_is_in_object);
}
++count;
}

53
test/mjsunit/regress/regress-2030.js Normal file
View File

@ -0,0 +1,53 @@
// Copyright 2012 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.
// Flags: --allow-natives-syntax
function a() {
this.x = 1;
}
var aa = new a();
%DebugPrint(aa);
function b() {
this.z = 23;
this.x = 2;
}
var bb = new b();
%DebugPrint(bb);
function f(o) {
return o.x;
}
assertSame(1, f(aa));
assertSame(1, f(aa));
assertSame(2, f(bb));
assertSame(2, f(bb));
%OptimizeFunctionOnNextCall(f);
assertSame(1, f(aa));
assertSame(2, f(bb));