A register allocation bugfix....

A register allocation bugfix.

The function that prepares a virtual frame slot for writing (in order
to preserve the copy-on-write semantics of aliased frame elements) can
allocate registers, which may spill one from the frame.  If we're
unlucky, the spilled register can be the source register for the frame
element write.  In that case, ensure we do the write from memory.


Committed: http://code.google.com/p/v8/source/detail?r=1904

[Kevin Millikin (Chromium), 2009-05-08 10:20:37]

This is annoyingly subtle behavior.

It's convenient to have local names for frame elements.

It's not safe to declare top a FrameElement&, because something could cause the
list backing store to be resized.

We will need to identify the functions that can change an arbitrary frame
element, then carefully audit the places where we use a local name for a copy of
a frame element to make sure that it is safe.

[iposva, 2009-05-08 15:45:33]

LGTM

Have you filed a bug to go and identify other potential candidates?

-Ivan