[Vm-dev] Cog and #commonSend are getting me crazy :(
Mariano Martinez Peck
marianopeck at gmail.com
Fri Apr 29 21:37:03 UTC 2011
http://code.google.com/p/cog/issues/detail?id=39
On Fri, Apr 29, 2011 at 7:19 PM, Eliot Miranda <eliot.miranda at gmail.com>wrote:
>
>
>
> On Fri, Apr 29, 2011 at 4:31 AM, Luc Fabresse <luc.fabresse at gmail.com>wrote:
>
>>
>> yes clearly.
>> some doc on tools and hints for VM debugging.
>> It is particularly hard and interesting ;-)
>>
>
> If you want to find out what there is to document then at the external
> level do this:
>
> Cog.app/Contents/MacOS/Croquet -?
> unknown option: -?
> Usage: Fast.app/Contents/MacOS/Croquet [<option>...] [<imageName>
> [<argument>...]]
> Fast.app/Contents/MacOS/Croquet [<option>...] -- [<argument>...]
>
> Common <option>s:
> -help print this help message, then exit
> -memory <size>[mk] use fixed heap size (added to image size)
> -eden <size>[mk] set eden memory to bytes
> -stackpages num use n stack pages
> -breaksel selector set breakpoint on send of selector
> -codesize <size>[mk] set machine code memory to bytes
> -sendtrace[=num] enable send tracing (optionally to a specific
> value)
> -tracestores enable store tracing (assert check stores)
> -cogmaxlits <n> set max number of literals for methods compiled to
> machine code
> -cogminjumps <n> set min number of backward jumps for interpreted
> methods to be considered for compilation to machine code
> -pathenc <enc> set encoding for pathnames (default: macintosh)
> -headless run in headless (no window) mode (default: false)
>
> Notes:
> <imageName> defaults to `Squeak.image'.
> If `-memory' is not specified then the heap will grow dynamically.
> <argument>s are ignored, but are processed by the Squeak image.
> The first <argument> normally names a Squeak `script' to execute.
> Precede <arguments> by `--' to use default image.
>
> In particular "-breaksel selector", "-sendtrace[=num]" & "-tracestores" are
> interesting for debugging.
>
> Inside the system you would need to document all the various facilities for
> debugging; the print methods in the interpreters, the break-pointing
> facilities in the CogVMSimulator et al. There's a lot there. I can of
> courser help and I have workspaces with various versions of it. But this
> isn't going to be easy to document fully, not least because it changes as
> needs require.
>
> best
> Eliot
>
>
>> #Luc
>>
>>
>> 2011/4/29 stephane ducasse <stephane.ducasse at gmail.com>
>>
>>>
>>> Mariano can you document that somewhere :)
>>>
>>> On Apr 28, 2011, at 11:59 PM, Mariano Martinez Peck wrote:
>>>
>>> > Hi Eliot. Thanks for answering. Your answer was EXTREMELY useful. Not
>>> only because it helped me to solve the problem I was having, but also
>>> because I discovered a wonderful tool.
>>> >
>>> > You are smart :) I like the solution. So, if I understood correctly, I
>>> can put a breakpoint in the function warning() with "break warning". With
>>> the -breaksel parameter you set an instVar with the selector name and size.
>>> Then after, anywhere I can send #compilationBreak: selectorOop point:
>>> selectorLength and that will magically check whether the selectorOop is
>>> the one I passes with -breaksel and if true, it will call warning, who has a
>>> breakpoint, hence, I can debug :) AWESOME!!!! Now with CMake I can even
>>> generate a xcode project and debug it :) (I don't know why attaching gdb
>>> from Xcode crash the vm).
>>> >
>>> > One little comment....I have an error using Cocoa VM builds because
>>> sqMacUnixCommandLineInterface.c is only for /platforms/MacOS and not for
>>> /platforms/IOS/
>>> > I am not sure how this should be integrated in Cocoa branch.
>>> >
>>> > Thanks Eliot, I like having a kind of #haltIf: in the vm :)
>>> >
>>> > Mariano
>>> >
>>> >
>>> > On Thu, Apr 28, 2011 at 7:00 PM, Eliot Miranda <
>>> eliot.miranda at gmail.com> wrote:
>>> >
>>> > 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
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> >
>>> > --
>>> > Mariano
>>> > http://marianopeck.wordpress.com
>>> >
>>>
>>>
>>
>>
>
>
--
Mariano
http://marianopeck.wordpress.com
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