Re: context pointer always NULL for "c-tor" when created w/ Reflex::ClassBuilder::AddFunctionMember ?

From: Axel Naumann <Axel.Naumann_at_cern.ch>
Date: Tue, 17 May 2011 14:38:29 +0200

Hi Sebastien,

thanks for your report + diagnosis. That's now fixed in the trunk.

Cheers, Axel.

Sebastien Binet wrote on 05/17/2011 01:33 PM:
> On Tue, 17 May 2011 12:22:16 +0200, Sebastien Binet <binet_at_cern.ch> wrote:

>> On Tue, 17 May 2011 11:04:10 +0200, Axel Naumann <Axel.Naumann_at_cern.ch> wrote:
>>> Hi Sebastien,
>>>
>>> I don't know how you bind it to Go. How does the constructor get
>>> invoked?
>> that's probably done by TTree/TBranch... I am not calling it directly.
>>
>>> I.e. is Reflex::FunctionMember::Invoke() really called? Can you
>>> send the backtrace?
>> ah! got it.
>> it is probably b/c of:
>> http://root.cern.ch/lxr/source/cint/reflex/src/Object.cxx#89
>>  80 //-------------------------------------------------------------------------------
>>  81 // Invoke a data member of this object. Sign can be used for finding overloaded funs.
>>  82 // Put return value(if not void) into ret.
>>  83    Member m = TypeOf().FunctionMemberByName(fm, sign);
>>  84 
>>  85    if (!m) {
>>  86       throw RuntimeError("No such MemberAt " + fm);
>>  87    }
>>  88 
>>  89    m.Invoke(*this, ret, args);
>>  90 }

>
> arf... scratch that. I have of course been confusing all of these
> Invokes...
>
> here is the backtrace:
> (gdb) bt
> #0 ctor_Event (retaddr=0x0, mem=0xa55500, args=0x86a5d0, ctx=0x0)
> at ../src/externals/go-io-benchmarks/cmds/croot_event.h:45
> #1 0x00007ffff4153438 in ROOT::Cintex::Constructor_stub_with_context(ROOT::Cintex::StubContext_t*, G__value*, char const*, G__param*, int) () from /usr/lib/root/libCintex.so.5.28
> #2 0x00007ffff65d6d17 in Cint::G__ClassInfo::New() () from /usr/lib/root/libCint.so.5.28
> #3 0x00007ffff712611a in TClass::New(TClass::ENewType) const () from /usr/lib/root/libCore.so.5.28
> #4 0x00007ffff7126f9b in TClass::BuildRealData(void*, bool) () from /usr/lib/root/libCore.so.5.28
> #5 0x00007ffff5e2b3ea in TStreamerInfo::Build() () from /usr/lib/root/libRIO.so.5.28
> #6 0x00007ffff71222c3 in TClass::GetStreamerInfo(int) const () from /usr/lib/root/libCore.so.5.28
> #7 0x00007ffff5e2c6df in TStreamerInfo::BuildOld() () from /usr/lib/root/libRIO.so.5.28
> #8 0x00007ffff71221ac in TClass::GetStreamerInfo(int) const () from /usr/lib/root/libCore.so.5.28
> #9 0x00007ffff620c7b6 in TBranchElement::InitInfo() () from /usr/lib/root/libTree.so.5.28
> #10 0x00007ffff620b10c in TBranchElement::SetAddress(void*) () from /usr/lib/root/libTree.so.5.28
> #11 0x00007ffff623aed4 in TTree::SetBranchAddressImp(TBranch*, void*, TBranch**) () from /usr/lib/root/libTree.so.5.28
> #12 0x0000000000402392 in tree0 (f=<value optimized out>) at ../src/externals/go-io-benchmarks/cmds/croot-read-new-struct.c:23
> #13 0x0000000000401857 in main (argc=1, argv=0x7fffffffe558) at ../src/externals/go-io-benchmarks/cmds/croot-read-new-struct.c:71
>
> -s
>

>>
>> Object::Invoke not passing m.Stubcontext() to m.Invoke...
>>
>> -s
>>
>>
>>>
>>> Cheers, Axel.
>>>
>>>
>>> Sebastien Binet wrote on 05/17/2011 10:46 AM:
>>>>
>>>> hi there,
>>>>
>>>> (still playing with Go)
>>>> I am seeing something rather strange:
>>>>
>>>> say I have these structs:
>>>>
>>>> /** edm **/
>>>> typedef struct {
>>>>   double E;
>>>>   double T;
>>>> } Det;
>>>>
>>>> typedef struct {
>>>>   Det A;
>>>>   Det B;
>>>> } Event;
>>>>
>>>> size_t g_sz_det = sizeof(Det);
>>>> size_t g_sz_evt = sizeof(Event);
>>>>
>>>>
>>>> and the corresponding c-tor stub functions:
>>>> /* stub functions for Event */
>>>> void ctor_Event(void *retaddr, void *mem, void* args, void* ctx)
>>>> {
>>>>   fprintf(stderr, "::ctor-fct[Event] [%p] [%p] [%p] [%p]\n", retaddr, mem, args, ctx);
>>>>   void* dummy = 0;
>>>>   if (retaddr) *(void**)retaddr = (Event*)realloc(mem, sizeof(Event));
>>>>   else dummy = (Event*)realloc(mem, sizeof(Event));
>>>>   if (dummy) {}
>>>> }
>>>>
>>>> /* etc... */
>>>>
>>>> the ctor_Event stub function is attached to the Event Reflex::Type like
>>>> so:
>>>> Reflex::ClassBuilder cb = ...;
>>>> Reflex::Type ty_ctor = Reflex::FunctionTypeBuilder(ty_void);
>>>> void *ctx = &g_sz_evt;
>>>> cb.AddFunctionMember(ty_ctor, "Event", &ctor_Event, ctx, NULL,
>>>>                      Reflex::PUBLIC|Reflex::CONSTRUCTOR);
>>>>
>>>>
>>>> so far so good, and when iterating over the function members of the
>>>> "Event" type I do see:
>>>> :: Evt-size: 32 32
>>>> :: Evt-mbrs: 2
>>>> :: Evt-type: 117
>>>> :: Evt-name: Event
>>>> :: Evt-id:   0x11c28d0
>>>> :: Evt-fct-mbrs: 3
>>>> ::  fct-mbr[0][Event] - ctx [0x6033b8] stub-fct[0x401960]
>>>> ::  fct-mbr[1][IsA] - ctx [0x11c3910] stub-fct[0x7f9892ed2290]
>>>> ::  fct-mbr[2][ShowMembers] - ctx [0x11c3910] stub-fct[0x7f9892ed1d00]
>>>>
>>>> ie: the correct address for both the context pointer and the stub
>>>> function (calling resp. Member::Stubcontext() and Member::Stubfunction())
>>>>
>>>> but when the ctor_Event function is invoked:
>>>> ::ctor-fct[Event] [(nil)] [0x13b3500] [0x11c85d0] [(nil)]
>>>>
>>>> the ctx pointer is always NULL, eventhough FunctionMember::Invoke does
>>>> pass the fStubCtx to fStubFP:
>>>>
>>>>    // parameters need more checking FIXME
>>>>    fStubFP(retaddr, mem, paramList, fStubCtx);
>>>>
>>>>
>>>> (I'd like to use that context pointer to pass a few extra informations
>>>> needed for the proper initialization of the Go runtime when
>>>> instantiating the struct instance...)
>>>>
>>>> am I doing something wrong ?
>>>>
>>>> -s
>>>>
>>
>> -- 
>> #########################################
>> # Dr. Sebastien Binet
>> # Laboratoire de l'Accelerateur Lineaire
>> # Universite Paris-Sud XI
>> # Batiment 200
>> # 91898 Orsay
>> #########################################

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Received on Tue May 17 2011 - 14:38:34 CEST