Menu
▾
▴
Re: [Swig-devel] [MATLAB] strange problem with sym:name of base-class
|
From: Kris T. <kri...@gm...> - 2014-06-21 22:32:25
|
> From: William Fulton, Sent: 18 June 2014 07:39
> On 15/06/14 17:29, Kris Thielemans wrote:
> >>From William Fulton, Sent: 10 June 2014 19:14
> >> On 08/06/14 12:25, Kris Thielemans wrote:
> >>> Hi
> >>>
> >>> I'm trying to get the matlab module to work and have a very strange
> >> problem. In MATLAB::classHandler, we go through the list of
base-classes
> > to
> >> output those to matlab. The code goes as follows
> >>>
> >>> List *baselist = Getattr(n, "bases");
> >>> if(baselist){
> >>> // Loop over base classes
> >>> for (Iterator b = First(baselist); b.item; b = Next(b)) {
> >>> // Get base class name, possibly ignore
> >>> String *bname = Getattr(b.item, "sym:name");
> >>> // Etc
> >>> }
> >>>
> >>> This works nicely most of the time, but for 2 classes in my project,
the
> >> resulting bname is set to "destructor" which comes from nowhere (I
assure
> > you
> >> I have no destructor class), even though the "name" attribute is
correct
> > (in my
> >> case for instance "stir::ProjData"). I can't see anything special for
> > these classes.
> >>>
> >>> Any idea where this comes from or how I can debug this?
> >>
> >> Sounds like a bug somewhere. Get a short testcase and look at the
output
> >> of -debug-csymbols and -debug-symbols. Also -debug-module 1 and see if
> >> anything goes haywire as you increase upwards from 1.
> >>
> >
> > thanks William
> >
> > I've boiled this down to a very short test-case (see below). This
happens
> > when using a forward-declaration for a class. The problem shows up at
stage
> > 4 (using the debug-module) switch, stage 3 is ok. I've checked that the
> > print-out of debug-module when using python or octave output is fine, so
it
> > is indeed a bug in the matlab module. I have no idea how to find out
where
> > this happens.
> >
> >
> > Here's the example interface file
> > ---------------------------
> > %module swigtest
> > %{
> > %}
> > %inline %{
> >
> > class A;
> >
> > class B
> > {
> > public:
> > B(const A&) {}
> > };
> >
> > class A
> > {};
> >
> > class A2: public A
> > {
> > A2() : A() {}
> > };
> > %}
> > ----------------------------
> >
> > When I run this with the matlab module, e.g.
> >
> > swig -matlab -c++ -debug-module 4 -o wrap.cpp swigtest.i
> >
> > the output is like this
> >
> > +++ classforward ----------------------------------------
> > | sym:name - "A"
> > | name - "A"
> > | kind - "class"
> > | sym:weak - "1"
> > | sym:symtab - 0x7f674db2f8f0
> > | sym:overname - "__SWIG_0"
> > |
> > +++ class ----------------------------------------
> > | classtype - "B"
> > | name - "B"
> > | sym:symtab - 0x7f674db2f8f0
> > | symtab - 0x7f674da94230
> > | allows_typedef - "1"
> > | typepass:visit - "1"
> > | allocate:visit - "1"
> > | kind - "class"
> > | sym:name - "B"
> > | allocate:has_constructor - "1"
> > | allocate:public_constructor - "1"
> > | allocate:copy_constructor - "1"
> > | allocate:default_destructor - "1"
> > | has_destructor - "1"
> > | allocate:destructor - "1"
> > | has_constructor - "1"
> > | classtypeobj - "B"
> > | module - 0x7f674da93e90
> > | sym:overname - "__SWIG_0"
> > | typescope - 0x7f674da95410
> >
> > +++ access ----------------------------------------
> > | kind - "public"
> > |
> > +++ constructor ----------------------------------------
> > | name - "B"
> > | ismember - "1"
> > | sym:symtab - 0x7f674da94230
> > | sym:name - "B"
> > | view - "constructorDeclaration"
> > | wrap:parms - A const &
> > | decl - "f(r.q(const).A)."
> > | tmap:out - "_out =
SWIG_NewPointerObj(SWIG_as_voidptr(result),
> > SWIGTYPE_p_B, 1 | 0 );"
> > | access - "public"
> > | parms - A const &
> > | wrap:action - "result = (B *)new B((A const &)*arg1);"
> > | wrap:name - "_wrap_new_B"
> > | code - "{}"
> > | tmap:out:noblock - "1"
> > | sym:overname - "__SWIG_0"
> > | feature:new - "1"
> > |
> > +++ access ----------------------------------------
> > | kind - "public"
> > |
> > +++ destructor ----------------------------------------
> > | name - "~B"
> > | sym:symtab - 0x7f674da94230
> > | view - "destructorDeclaration"
> > | sym:name - "~B"
> > | wrap:parms - B *self
> > | decl - "f()."
> > | tmap:out - "_out = (mxArray*)0;"
> > | access - "public"
> > | wrap:action - "delete arg1;"
> > | wrap:name - "_wrap_delete_B"
> > | tmap:out:noblock - "1"
> > | sym:overname - "__SWIG_0"
> > |
> > +++ class ----------------------------------------
> > | classtype - "A"
> > | name - "A"
> > | sym:symtab - 0x7f674db2f8f0
> > | symtab - 0x7f674da947f0
> > | allows_typedef - "1"
> > | typepass:visit - "1"
> > | allocate:visit - "1"
> > | kind - "class"
> > | sym:name - "destructor"
> > | allocate:default_constructor - "1"
> > | allocate:copy_constructor - "1"
> > | allocate:default_destructor - "1"
> > | has_default_constructor - "1"
> > | has_destructor - "1"
> > | allocate:destructor - "1"
> > | has_constructor - "1"
> > | classtypeobj - "A"
> > | module - 0x7f674da93e90
> > | sym:overname - "__SWIG_0"
> > | typescope - 0x7f674da95650
> >
> >
> > Etc
> >
> > where you see that sym:name of class A is set to "destructor" (in pass 3
> > it's still "A").
> > any suggestions?
> >
> I'd guess either memory corruption or possibly some other bug where the
> sym:name is explicitly set. If you've tried the memory debugging
> techniques I posted a few days ago on 10 June without any luck, I'd
> liberally sprinkle calls to Swig_print passing the class node in code
> that handles the class to try and see when it goes wrong.
>
Thanks William, #defining DOH_DEBUG_MEMORY_POOLS did the trick. It threw up
an assert(!DOH_object_already_deleted). It turned out that in
MATLAB::classHandler we were Deleting a String obtained via GetAttr, which
is incorrect (as that meant we were deleting the attribute). After fixing
that, this problem disappeared. Great!
Joel, I've committed this on my github fork.
Kris
|