Hydrogen support for context allocated harmony bindings.

Hydrogen support for context allocated harmony bindings.

This CL adds support for loading from and storing to context slots
belonging to harmony let or const bound variables. Checks for the
hole value are performed and the function is deoptimized if they fail.
The full-codegen generated code will take care of properly throwing
a reference error in these cases.

TEST=mjsunit/harmony/block-let-crankshaft.js

Committed: http://code.google.com/p/v8/source/detail?r=10220

[Steven, 2011-12-06 14:36:48]

PTAL.

[fschneider, 2011-12-08 12:58:54]

http://codereview.chromium.org/8820015/diff/1/test/mjsunit/harmony/block-let-...
File test/mjsunit/harmony/block-let-crankshaft.js (right):

http://codereview.chromium.org/8820015/diff/1/test/mjsunit/harmony/block-let-...
test/mjsunit/harmony/block-let-crankshaft.js:98: function f13(x) {
Where is f13-f23 invoked and optimized? I don't see them added to the array
above.

[Steven, 2011-12-08 14:25:41]

I added the missing functions to the array. Furthermore I removed the usage of
the Variable object again. This is not so nice if you want for example to load
the closure field from a context. Please take another look.

http://codereview.chromium.org/8820015/diff/1/test/mjsunit/harmony/block-let-...
File test/mjsunit/harmony/block-let-crankshaft.js (right):

http://codereview.chromium.org/8820015/diff/1/test/mjsunit/harmony/block-let-...
test/mjsunit/harmony/block-let-crankshaft.js:98: function f13(x) {
On 2011/12/08 12:58:54, fschneider wrote:
> Where is f13-f23 invoked and optimized? I don't see them added to the array
> above.

Done.

[fschneider, 2011-12-09 08:37:40]

LGTM with one more comment:

http://codereview.chromium.org/8820015/diff/5001/src/hydrogen-instructions.h
File src/hydrogen-instructions.h (right):

http://codereview.chromium.org/8820015/diff/5001/src/hydrogen-instructions.h#...
src/hydrogen-instructions.h:3510: : slot_index_(var->index()) {
I'm not convinced that two constructors are better here: I'd rather see at the
call-site which mode is used (with or without hole-check) instead of
distributing the logic into different files.

[Steven, 2011-12-09 09:44:56]

http://codereview.chromium.org/8820015/diff/5001/src/hydrogen-instructions.h
File src/hydrogen-instructions.h (right):

http://codereview.chromium.org/8820015/diff/5001/src/hydrogen-instructions.h#...
src/hydrogen-instructions.h:3510: : slot_index_(var->index()) {
On 2011/12/09 08:37:40, fschneider wrote:
> I'm not convinced that two constructors are better here: I'd rather see at the
> call-site which mode is used (with or without hole-check) instead of
> distributing the logic into different files.

Agreed.