[Vm-dev] Cog and #commonSend are getting me crazy :(

[Eliot Miranda]

Mariano,

    here's a hint.  Look at the command-line argument breaksel and see where
it is used.  This will call warning whenever a specific message is sent.
 e.g.

McStalker.macbuild$ gdb Debug.app/
GNU gdb 6.3.50-20050815 (Apple version gdb-1515) (Sat Jan 15 08:33:48 UTC
2011)
Copyright 2004 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain
conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "x86_64-apple-darwin"...Reading symbols for
shared libraries ................ done

(gdb) break warning
Breakpoint 1 at 0x105e2b: file
/Users/eliot/Cog/oscogvm/macbuild/../src/vm/gcc3x-cointerp.c, line 39.
(gdb) run -breaksel initialize ~/Squeak/Squeak4.2/trunk4.2.image
Starting program:
/Users/eliot/Cog/oscogvm/macbuild/Debug.app/Contents/MacOS/Croquet -breaksel
initialize ~/Squeak/Squeak4.2/trunk4.2.image
Reading symbols for shared libraries
.+++++++++++++++.....................................................................................
done
Reading symbols for shared libraries . done

Breakpoint 1, warning (s=0x16487c "send breakpoint (heartbeat suppressed)")
at /Users/eliot/Cog/oscogvm/macbuild/../src/vm/gcc3x-cointerp.c:39
39              printf("\n%s\n", s);
(gdb) where 5
#0  warning (s=0x16487c "send breakpoint (heartbeat suppressed)") at
/Users/eliot/Cog/oscogvm/macbuild/../src/vm/gcc3x-cointerp.c:39
#1  0x0010b490 in interpret () at
/Users/eliot/Cog/oscogvm/macbuild/../src/vm/gcc3x-cointerp.c:4747
#2  0x0011d521 in enterSmalltalkExecutiveImplementation () at
/Users/eliot/Cog/oscogvm/macbuild/../src/vm/gcc3x-cointerp.c:14103
#3  0x00124bc7 in initStackPagesAndInterpret () at
/Users/eliot/Cog/oscogvm/macbuild/../src/vm/gcc3x-cointerp.c:17731
#4  0x00105ec9 in interpret () at
/Users/eliot/Cog/oscogvm/macbuild/../src/vm/gcc3x-cointerp.c:1933
(More stack frames follow...)

On Thu, Apr 28, 2011 at 5:26 AM, Mariano Martinez Peck <
marianopeck at gmail.com> wrote:

>
> Hi Eliot. I am fighting since several hours with something in Cog and I
> cannot realize it. I am blind.
>
> I need to intercept all messages sent to an object. I have already done
> this for Interpreter VM and for StackVM. Now,  I am trying latest CogMTVM,
> and there is something I am not sying...I have this test:
>
> testBlah
>
>     ClassWith1Var new fooLong.
>     ClassWith1Var new fooLong.
>     ClassWith1Var new fooLong.
>
>
> ClassWith1Var >> fooLong
>     | aaa |
>     Object new.
>     self foo.
>
>
> Now, I modified
>
> CoInterpreter >> commonSend
>     "Send a message, starting lookup with the receiver's class."
>     "Assume: messageSelector and argumentCount have been set, and that
>     the receiver and arguments have been pushed onto the stack,"
>     "Note: This method is inlined into the interpreter dispatch loop."
>     <sharedCodeNamed: 'commonSend' inCase: 131>
>     self sendBreak: messageSelector + BaseHeaderSize
>         point: (objectMemory lengthOf: messageSelector)
>         receiver: (self internalStackValue: argumentCount).
>     cogit recordSendTrace ifTrue:
>         [self recordTrace: lkupClass thing: messageSelector source:
> TraceIsFromInterpreter].
>     self internalFindNewMethod.
>     self print: 'called: '; printStringOf: messageSelector; cr.
>     self internalExecuteNewMethod.
>     self fetchNextBytecode
>
>
> And when running the VM from gdb, 'called: fooLong'  doesn't appear at
> all!!!  why ?
> In addition, it appears 'called: foo' which is correct because #fooLong
> sends #foo
> but it appears only ONCE.
>
> #fooLong as I can see is not a quick return method but instead it goes by
> #sendLiteralSelector0ArgsBytecode. But the same happens if I put the print
> in that method... (which makes sense).
> I tried with a StackVM and the same....so it seems that #fooLong is going
> by another place than #commonSend.
>
> As far as I understand, there is nothing related with PIC or Jitt. In any
> of those cases, as what I can see, the #commonSend is called anyways.
>
> So...I am completly lost.
>
> Thanks in advance for any help.
>
> --
> Mariano
> http://marianopeck.wordpress.com
>
>
>
-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.squeakfoundation.org/pipermail/vm-dev/attachments/20110428/e821299c/attachment-0001.htm