Fix handling of foreign callbacks in DefineOwnProperty.

Fix handling of foreign callbacks in DefineOwnProperty.

We use foreign callbacks to make some properties shadow internal values
but still behave as data properties from within JavaScript. This means
when a value is passed to Object.defineProperty() on such a property,
it should update the internal value instead of redefinind the property
and destroying the shadowing.

R=rossberg@chromium.org
BUG=v8:1530
TEST=mjsunit/regress/regress-1530,test262/S15.3.3.1_A4

Committed: http://code.google.com/p/v8/source/detail?r=10279

[rossberg, 2011-12-19 16:47:44]

lgtm

http://codereview.chromium.org/8996008/diff/1/src/runtime.cc
File src/runtime.cc (right):

http://codereview.chromium.org/8996008/diff/1/src/runtime.cc#newcode4333
src/runtime.cc:4333: // in defineProperty. Firefox disagrees here, and actually
changes the value.
80 characters

http://codereview.chromium.org/8996008/diff/1/src/runtime.cc#newcode4346
src/runtime.cc:4346: kNonStrictMode);
This should be KStrictMode, I think.

http://codereview.chromium.org/8996008/diff/1/test/mjsunit/regress/regress-15...
File test/mjsunit/regress/regress-1530.js (right):

http://codereview.chromium.org/8996008/diff/1/test/mjsunit/regress/regress-15...
test/mjsunit/regress/regress-1530.js:28: // Test that redefining the 'prototype'
property of a function object
Maybe test other magic properties of functions, too?

[Michael Starzinger, 2011-12-20 08:50:16]

Added new patch set. Landed.

http://codereview.chromium.org/8996008/diff/1/src/runtime.cc
File src/runtime.cc (right):

http://codereview.chromium.org/8996008/diff/1/src/runtime.cc#newcode4333
src/runtime.cc:4333: // in defineProperty. Firefox disagrees here, and actually
changes the value.
On 2011/12/19 16:47:44, rossberg wrote:
> 80 characters

Done.

http://codereview.chromium.org/8996008/diff/1/src/runtime.cc#newcode4346
src/runtime.cc:4346: kNonStrictMode);
On 2011/12/19 16:47:44, rossberg wrote:
> This should be KStrictMode, I think.

Done. On this code path it doesn't actually matter. The mode is only considered
for JavaScript accessors, but not for API nor foreign callbacks.

http://codereview.chromium.org/8996008/diff/1/test/mjsunit/regress/regress-15...
File test/mjsunit/regress/regress-1530.js (right):

http://codereview.chromium.org/8996008/diff/1/test/mjsunit/regress/regress-15...
test/mjsunit/regress/regress-1530.js:28: // Test that redefining the 'prototype'
property of a function object
On 2011/12/19 16:47:44, rossberg wrote:
> Maybe test other magic properties of functions, too?

Done. All other properties of function objects for which we use foreign
callbacks are non-writable, but I added checks that Object.defineProperty()
throws on them as expected.