Speed up access to global variables from eval scopes. Traverse the...

Speed up access to global variables from eval scopes.  Traverse the
surrounding context to figure out if the variable could be global.  If
the variable could be global we check context extension objects at
runtime and use a global LoadIC if no variables have been introduced
by eval.

Fix crash bug when loading function arguments from inside eval.  The 
shadowed variable in the DYNAMIC_LOCAL case does not rewrite to a slot in 
that case.


Committed: http://code.google.com/p/v8/source/detail?r=1348

[Kasper Lund, 2009-02-24 11:21:08]

LGTM.

http://codereview.chromium.org/28027/diff/25/26
File src/compilation-cache.h (right):

http://codereview.chromium.org/28027/diff/25/26#newcode83
Line 83: // tripple with the boilerplate. This may overwrite an existing
tripple -> triple

http://codereview.chromium.org/28027/diff/25/27
File src/objects.cc (right):

http://codereview.chromium.org/28027/diff/25/27#newcode5955
Line 5955: hash ^= String::cast(script->source())->Hash();
It's not clear that this is a great way of mixing the bits.

[Mads Ager (chromium), 2009-02-24 13:13:22]

On 2009/02/24 11:21:08, Kasper Lund wrote:
> LGTM.
> 
> http://codereview.chromium.org/28027/diff/25/26
> File src/compilation-cache.h (right):
> 
> http://codereview.chromium.org/28027/diff/25/26#newcode83
> Line 83: // tripple with the boilerplate. This may overwrite an existing
> tripple -> triple

Done.

> http://codereview.chromium.org/28027/diff/25/27
> File src/objects.cc (right):
> 
> http://codereview.chromium.org/28027/diff/25/27#newcode5955
> Line 5955: hash ^= String::cast(script->source())->Hash();
> It's not clear that this is a great way of mixing the bits.

As we discussed, there is no reason to use the source end position as part of
the hash.  I now xor the string hash codes and add the start position to get the
final hash value.