First step of refactoring expression contexts in the toplevel code...

First step of refactoring expression contexts in the toplevel code
generator.

Contexts are no longer stored in the AST but in the code generator's
state.  This means that the running the code generator selector is not
required to use the toplevel code generator (for instance, if we
already know that we can and should use it).


Committed: http://code.google.com/p/v8/source/detail?r=3645

[fschneider, 2010-01-19 12:36:10]

LGTM.

http://codereview.chromium.org/546075/diff/1/5
File src/compiler.cc (right):

http://codereview.chromium.org/546075/diff/1/5#newcode757
src/compiler.cc:757: if (!var->is_global()) {
This is clearer than before and should be fine.

It just seems confusing that VariableProxy::AsVariable() checks var_ for NULL
explicitly. Is there any case where it  still can be NULL?