Fix issue 825 (LiveEdit vs. function with no locals) for x64.

Fix issue 825 (LiveEdit vs. function with no locals) for x64.

Committed: https://code.google.com/p/v8/source/detail?r=11587

[Peter Rybin, 2012-05-14 21:08:04]

Hi Yang

I'm covering x64 here. I'm a bit sceptic about the quality of my asm code.
However, it works.

Peter

[Yang, 2012-05-16 09:59:01]

LGTM with comments addressed.

http://codereview.chromium.org/10387116/diff/2001/src/x64/debug-x64.cc
File src/x64/debug-x64.cc (right):

http://codereview.chromium.org/10387116/diff/2001/src/x64/debug-x64.cc#newcod...
src/x64/debug-x64.cc:117: __ Integer32ToSmi(kScratchRegister, kScratchRegister);
You can convert those values to smi using
    Smi* value = Smi::FromInt(123);
and then use MacroAssembler::Push(Smi*) to push them onto the stack. This way
you avoid smi conversions at runtime.

[Peter Rybin, 2012-05-16 21:14:57]

http://codereview.chromium.org/10387116/diff/2001/src/x64/debug-x64.cc
File src/x64/debug-x64.cc (right):

http://codereview.chromium.org/10387116/diff/2001/src/x64/debug-x64.cc#newcod...
src/x64/debug-x64.cc:117: __ Integer32ToSmi(kScratchRegister, kScratchRegister);
On 2012/05/16 09:59:01, Yang wrote:
> You can convert those values to smi using
>     Smi* value = Smi::FromInt(123);
> and then use MacroAssembler::Push(Smi*) to push them onto the stack. This way
> you avoid smi conversions at runtime.

And this is 2-6 times shorter in terms of generated code size!
Done