Allocate arguments object on-demand instead of at function entry....

Allocate arguments object on-demand instead of at function entry.
This allows Function.prototype.apply to not allocate the objects 
and copy the arguments directly from the stack.

Committed: http://code.google.com/p/v8/source/detail?r=2256

[Kasper Lund, 2009-06-24 06:55:07]

http://codereview.chromium.org/147075/diff/1/5
File src/ia32/codegen-ia32.cc (right):

http://codereview.chromium.org/147075/diff/1/5#newcode2267
Line 2267: Result a2 = frame_->Pop();
It would be nice to find a better way of achieving this.

[Mads Ager (chromium), 2009-06-24 07:52:16]

LGTM

Hairy stuff.  Do we want to do this on ARM.  We should do this on x64 as well. 
Maybe just add TODO(x64) for now in the codegen paths that need to change?

http://codereview.chromium.org/147075/diff/1/5
File src/ia32/codegen-ia32.cc (right):

http://codereview.chromium.org/147075/diff/1/5#newcode570
Line 570: return (scope_->num_heap_slots() > 0)
Could you add a short comment explaining the reason for doing eager allocation
when there are heap slots?

http://codereview.chromium.org/147075/diff/1/5#newcode2187
Line 2187: // Verify that we're invoking is Function.prototype.apply.
invoking is -> invoking

http://codereview.chromium.org/147075/diff/1/5#newcode2263
Line 2263: // Flip the apply function and the function we to call on the stack,
we to -> to