Enable register allocation for return statements. Make sure to...

Enable register allocation for return statements. Make sure to
prepare the frame for the return even in the try-finally and
try-catch cases that shadows the function return label.

Committed: http://code.google.com/p/v8/source/detail?r=1037

[Kevin Millikin (Chromium), 2009-01-07 10:25:11]

The issue with Forget is the serious one.  I think using "Drop" is all it takes
to make it work.

http://codereview.chromium.org/16567/diff/209/217
File src/codegen-ia32.cc (right):

http://codereview.chromium.org/16567/diff/209/217#newcode1651
Line 1651: result.Unuse();
Since the reference to eax is live in the next basic block, it should be passed
to Jump or Bind.

http://codereview.chromium.org/16567/diff/209/217#newcode1660
Line 1660: frame_->EmitPush(eax);  // Materialize result on the stack.
EmitPush assumes the frame is spilled.  This should be a plain Push of the
result.

http://codereview.chromium.org/16567/diff/209/214
File src/virtual-frame-ia32.cc (right):

http://codereview.chromium.org/16567/diff/209/214#newcode637
Line 637: Forget(height());
As discussed offline, Forget as it currently stands probably isn't the right
thing here.  It assumes that it is forgetting things below the actual stack
pointer, and it doesn't adjust the stack pointer itself but assumes someone else
has or will.

http://codereview.chromium.org/16567/diff/209/215
File src/virtual-frame-ia32.h (right):

http://codereview.chromium.org/16567/diff/209/215#newcode242
Line 242: // This avoid generating unnecessary merge code when jumping to the
avoids