Enable GC update for pointers in GenerateKeyedLoadICDebugBreak

Enable GC update for pointers in GenerateKeyedLoadICDebugBreak

Committed: http://code.google.com/p/v8/source/detail?r=3989

[Peter Rybin, 2010-03-01 01:05:08]

Hi Soren

In my using debugger (for liveedit development) I ran into a case when
KeyedLoadIC gets a broken pointer (pointer to object with zapped out fields).

From what I learned, a pointer does not survive garbage collection invoked from
debugger code. I guess we have to declare edx (and probably eax also) as
registers with pointers.

In my case (that crashes) KeyedLoadIC is called for reading argument #0 value.
So I can't really guess, whether "0" stored in eax is a direct integer or SMI.

Please advise, whether my guess is close to truth.

I will have to fix comments before committing, that's for sure.

Peter

[Søren Thygesen Gjesse, 2010-03-01 07:35:02]

On 2010/03/01 01:05:08, Peter Rybin wrote:
> Hi Soren
> 
> In my using debugger (for liveedit development) I ran into a case when
> KeyedLoadIC gets a broken pointer (pointer to object with zapped out fields).
> 
> From what I learned, a pointer does not survive garbage collection invoked
from
> debugger code. I guess we have to declare edx (and probably eax also) as
> registers with pointers.
> 
> In my case (that crashes) KeyedLoadIC is called for reading argument #0 value.
> So I can't really guess, whether "0" stored in eax is a direct integer or SMI.
> 
> Please advise, whether my guess is close to truth.
> 
> I will have to fix comments before committing, that's for sure.
> 
> Peter

Bill,

Can you have a look at this. Looks related to the change using registers when
calling IC's. Maybe we need some new tests for this?

/Søren

[William Hesse, 2010-03-01 16:14:21]

Good catch - thanks for doing this.  Add the additional fixes, and LGTM.

http://codereview.chromium.org/660257/diff/1/2
File src/ia32/debug-ia32.cc (right):

http://codereview.chromium.org/660257/diff/1/2#newcode153
src/ia32/debug-ia32.cc:153: //  -- eax    : key
edx    : receiver
eax    : key

http://codereview.chromium.org/660257/diff/1/2#newcode162
src/ia32/debug-ia32.cc:162: //  -- eax    : value
ecx     : key
edx     : receiver

http://codereview.chromium.org/660257/diff/1/2#newcode166
src/ia32/debug-ia32.cc:166: Generate_DebugBreakCallHelper(masm, eax.bit(),
false);
eax.bit() | ecx.bit() | edx.bit()

[Peter Rybin, 2010-03-01 17:11:26]

http://codereview.chromium.org/660257/diff/1/2
File src/ia32/debug-ia32.cc (right):

http://codereview.chromium.org/660257/diff/1/2#newcode153
src/ia32/debug-ia32.cc:153: //  -- eax    : key
On 2010/03/01 16:14:21, William Hesse wrote:
> edx    : receiver
> eax    : key

Done.

http://codereview.chromium.org/660257/diff/1/2#newcode162
src/ia32/debug-ia32.cc:162: //  -- eax    : value
On 2010/03/01 16:14:21, William Hesse wrote:
> ecx     : key
> edx     : receiver

Done.

http://codereview.chromium.org/660257/diff/1/2#newcode166
src/ia32/debug-ia32.cc:166: Generate_DebugBreakCallHelper(masm, eax.bit(),
false);
On 2010/03/01 16:14:21, William Hesse wrote:
> eax.bit() | ecx.bit() | edx.bit()

Done.