Hi Paul, hi all,

Paul, thanks for the review. I have commited this as r222361.

Regards,
	Andre

On Thu, 16 Apr 2015 21:13:31 +0200
Paul Richard Thomas <paul.richard.thomas@gmail.com> wrote:

> Hi Andre,
> 
> The delta patch is OK for trunk and eventual backport to 5.2.
> 
> Thanks for all the hard work
> 
> Paul
> 
> On 14 April 2015 at 19:00, Andre Vehreschild <vehre@gmx.de> wrote:
> > Hi all,
> >
> > during further testing of a big Fortran software I encounter two bugs with
> > class arrays, that are somehow connected to pr60322. I therefore propose an
> > extended patch for pr60322. Because Paul has already reviewed most the
> > extended patch, I give you two patches:
> >
> > 1. a full patch, fixing all the issues connected to pr60322, and
> > 2. a delta patch to get from the reviewed patch to the latest version.
> >
> > With the second patch I hope to get a faster review, because it is
> > significantly shorter.
> >
> > Now what was the issue? To be precise there were two issues:
> >
> > i. a pointer to a class array (CLASS_DATA(sym).attr.class_pointer == 1) was
> > dereferenced, which lead to an ICE (the patch for this in the delta is
> > chunk 5 in gfc_conv_expr_descriptor, and
> >
> > ii. (and this was a severe brain cracker) in chains of references
> > consisting of more then one class-(array)-ref always the _vptr of the first
> > symbol was taken and not the _vptr of the currently dereferenced class
> > object. This occurred when fortran code similiar to this was executed:
> >
> > type innerT
> >   integer, allocatable :: arr(:)
> > end type
> >
> > type T
> >   class(innerT) :: mat(:,:)
> > end type
> >
> > class(T) :: o
> >
> > allocate(o%mat(2,2))
> > allocate(o%mat(:,:)%arr(10)) ! This is obviously pseudo code,
> >         ! but I think you get what is meant.
> >
> > o%mat(1,1)%arr(1) = 1
> >
> > In the last line the address to get to arr(1) was computed using the
> > _vptr->size of o and not of o%mat(1,1). To fix this gfc_component_ref () now
> > computes the class' _vptr-ref whenever it does a _data-ref (chunk 1 of
> > trans-expr.c in the delta patch). The _vptr-ref is stored in gfc_se, where I
> > added the new member class_vptr. The gfc_se->class_vptr is then used in
> > array-refs (chunk 2 of trans.c) to get the size of the array elements of the
> > correct level.
> >
> > The other chunks of the delta patch are:
> > - parameter passing fixes, and
> > - documentation fixes as requested for the version 5 of the pr60322 patch.
> >
> > I hope this helps in getting the patch reviewed quickly.
> >
> > Bootstraps and regtests ok on x86_64-linux-gnu/F21.
> >
> > Ok for trunk -> 6.0?
> > Ok, for backport to 5.2, once available?
> >
> > Note, the patches may apply with shifts, as I forgot to update before taking
> > the diffs.
> >
> > Regards,
> >         Andre
> >
> > On Thu, 9 Apr 2015 14:37:09 +0200
> > Andre Vehreschild <vehre@gmx.de> wrote:
> >
> >> Hi Paul, hi all,
> >>
> >> Paul, thanks for the review. Answers to your questions are inline below:
> >>
> >> On Sun, 5 Apr 2015 11:13:05 +0200
> >> Paul Richard Thomas <paul.richard.thomas@gmail.com> wrote:
> >> <snip>
> >> > +  /* The dummy is returned for pointer, allocatable or assumed rank
> >> > arrays.
> >> > +     The check for pointerness needs to be repeated here (it is done in
> >> > +     IS_CLASS_ARRAY (), too), because for class arrays that are
> >> > pointers, as
> >> > +     is the one of the sym, which is incorrect here.  */
> >> >
> >> > What does this mean, please?
> >>
> >> The first sentence is about regular arrays and should be unchanged from the
> >> original source. Then I have to check for class (arrays) that are pointers,
> >> i.e., independent of whether the sym is a class array or a regular pointer
> >> to a class object. (The latter shouldn't make it into the routine anyway.)
> >> IS_CLASS_ARRAY () returns false for too many reasons to be of use here. I
> >> have to apologize and confess that the comment was a mere note to myself
> >> to not return to use is_classarray in the if below. Let me rephrase the
> >> comment to be:
> >>
> >> /* The dummy is returned for pointer, allocatable or assumed rank arrays.
> >>    For class arrays the information if sym is an allocatable or pointer
> >>    object needs to be checked explicitly (IS_CLASS_ARRAY can be false for
> >>    too many reasons to be of use here).  */
> >>
> >> > +      /* Returning the descriptor for dummy class arrays is hazardous,
> >> > because
> >> > +     some caller is expecting an expression to apply the component refs
> >> > to.
> >> > +     Therefore the descriptor is only created and stored in
> >> > +     sym->backend_decl's GFC_DECL_SAVED_DESCRIPTOR.  The caller is then
> >> > +     responsible to extract it from there, when the descriptor is
> >> > +     desired.  */
> >> > +      if (IS_CLASS_ARRAY (sym)
> >> > +      && (!DECL_LANG_SPECIFIC (sym->backend_decl)
> >> > +          || !GFC_DECL_SAVED_DESCRIPTOR (sym->backend_decl)))
> >> > +    {
> >> > +      decl = gfc_build_dummy_array_decl (sym, sym->backend_decl);
> >> > +      /* Prevent the dummy from being detected as unused if it is
> >> > copied. */
> >> > +      if (sym->backend_decl != NULL && decl != sym->backend_decl)
> >> > +        DECL_ARTIFICIAL (sym->backend_decl) = 1;
> >> > +      sym->backend_decl = decl;
> >> > +    }
> >> >
> >> > The comments, such as the above are often going well beyond column 72,
> >> > into the 80's. I know that much of the existing code violates this
> >> > style requirement but there is no need to do so if clarity is not
> >> > reduced thereby.
> >>
> >> Er, the document at
> >>
> >> https://gcc.gnu.org/codingconventions.html#C_Formatting
> >>
> >> says that line length is 80, or is there another convention, that I am not
> >> aware of?
> >>
> >> > In trans-stmt.c s/standart/standard/
> >>
> >> Fixed.
> >>
> >> > Don't forget to put the PR numbers in the ChangeLogs.
> >>
> >> I won't anymore, already got told off :-)
> >>
> >> > For this submission, I would have appreciated some a description of
> >> > what each chunk in the patch is doing, just because there is so much
> >> > of it. I suppose that it was good for my imortal soul to sort it out
> >> > for myself but it took a little while :-)
> >>
> >> I initially tried to split the submission in two parts to make it more
> >> manageable. One part with the brain-dead substitutions of as and array_attr
> >> and one with the new code. Albeit I failed to get the brain-dead part right
> >> and made some mistakes there already, which Mikael pointed out. I therefore
> >> went for the big submission.
> >>
> >> Now doing a description of what each "chunk" does is quite tedious. I
> >> really would like to spend my time more productive. Would you be
> >> satisfied, when I write a story about the patch, referring to some parts
> >> more explicitly, like
> >>
> >> "Chunk 4 of file trans-stmt.c is the heart of the patch and does this and
> >> that. The remaining chunks are more or less putting the data together."
> >>
> >> (This is not correct for this patch of course. Just an example.) More
> >> elaborate of course, but just to give an idea.
> >>
> >> Thanks again. I will commit as soon as 5.2/6.0 commit window is open.
> >>
> >> Regards,
> >>       Andre
> >>
> >> >
> >> > Cheers and many thanks for the patch.
> >> >
> >> > Paul
> >> >
> >> > On 27 March 2015 at 13:48, Paul Richard Thomas
> >> > <paul.richard.thomas@gmail.com> wrote:
> >> > > Dear Andre,
> >> > >
> >> > > I am in the UK as of last night. Before leaving, I bootstrapped and
> >> > > regtested your patch and all was well. I must drive to Cambridge this
> >> > > afternoon to see my mother and will try to get to it either this
> >> > > evening or tomorrow morning. There is so much of it and it touches
> >> > > many places; so I must give it a very careful looking over before
> >> > > giving the green light. Bear with me please.
> >> > >
> >> > > Great work though!
> >> > >
> >> > > Paul
> >> > >
> >> > > On 24 March 2015 at 18:06, Andre Vehreschild <vehre@gmx.de> wrote:
> >> > >> Hi all,
> >> > >>
> >> > >> I have worked on the comments Mikael gave me. I am now checking for
> >> > >> class_pointer in the way he pointed out.
> >> > >>
> >> > >> Furthermore did I *join the two parts* of the patch into this one,
> >> > >> because keeping both in sync was no benefit but only tedious and did
> >> > >> not prove to be reviewed faster.
> >> > >>
> >> > >> Paul, Dominique: I have addressed the LOC issue that came up lately.
> >> > >> Or rather the patch addressed it already. I feel like this is not
> >> > >> tested very well, not the loc() call nor the sizeof() call as given
> >> > >> in the 57305 second's download. Unfortunately, is that download not
> >> > >> runable. I would love to see a test similar to that download, but
> >> > >> couldn't come up with one, that satisfied me. Given that the patch's
> >> > >> review will last some days, I still have enough time to come up with
> >> > >> something beautiful which I will add then.
> >> > >>
> >> > >> Bootstraps and regtests ok on x86_64-linux-gnu/F20.
> >> > >>
> >> > >> Regards,
> >> > >>         Andre
> >> > >>
> >> > >>
> >> > >> On Tue, 24 Mar 2015 11:13:27 +0100
> >> > >> Paul Richard Thomas <paul.richard.thomas@gmail.com> wrote:
> >> > >>
> >> > >>> Dear Andre,
> >> > >>>
> >> > >>> Dominique pointed out to me that the 'loc' patch causes a ICE in the
> >> > >>> testsuite. It seems that 'loc' should provide the address of the
> >> > >>> class container in some places and the address of the data in
> >> > >>> others. I will put my thinking cap on tonight :-)
> >> > >>>
> >> > >>> Cheers
> >> > >>>
> >> > >>> Paul
> >> > >>>
> >> > >>> On 23 March 2015 at 13:43, Andre Vehreschild <vehre@gmx.de> wrote:
> >> > >>> > Hi Mikael,
> >> > >>> >
> >> > >>> > thanks for looking at the patch. Please note, that Paul has sent an
> >> > >>> > addendum to the patches for 60322, which I deliberately have
> >> > >>> > attached.
> >> > >>> >
> >> > >>> >>  26/02/2015 18:17, Andre Vehreschild a écrit :
> >> > >>> >> > This first patch is only preparatory and does not change any of
> >> > >>> >> > the semantics of gfortran at all.
> >> > >>> >> Sure?
> >> > >>> >
> >> > >>> > With the counterexample you found below, this of course is a wrong
> >> > >>> > statement.
> >> > >>> >
> >> > >>> >> > diff --git a/gcc/fortran/expr.c b/gcc/fortran/expr.c
> >> > >>> >> > index ab6f7a5..d28cf77 100644
> >> > >>> >> > --- a/gcc/fortran/expr.c
> >> > >>> >> > +++ b/gcc/fortran/expr.c
> >> > >>> >> > @@ -4059,10 +4060,10 @@ gfc_lval_expr_from_sym (gfc_symbol *sym)
> >> > >>> >> >    lval->symtree = gfc_find_symtree (sym->ns->sym_root,
> >> > >>> >> > sym->name);
> >> > >>> >> >
> >> > >>> >> >    /* It will always be a full array.  */
> >> > >>> >> > -  lval->rank = sym->as ? sym->as->rank : 0;
> >> > >>> >> > +  as = sym->as;
> >> > >>> >> > +  lval->rank = as ? as->rank : 0;
> >> > >>> >> >    if (lval->rank)
> >> > >>> >> > -    gfc_add_full_array_ref (lval, sym->ts.type == BT_CLASS ?
> >> > >>> >> > -                       CLASS_DATA (sym)->as : sym->as);
> >> > >>> >> > +    gfc_add_full_array_ref (lval, as);
> >> > >>> >>
> >> > >>> >> This is a change of semantics.  Or do you know that
> >> > >>> >> sym->ts.type != BT_CLASS?
> >> > >>> >
> >> > >>> > You are completely right. I have made a mistake here. I have to
> >> > >>> > tell the truth, I never ran a regtest with only part 1 of the
> >> > >>> > patches applied. The second part of the patch will correct this,
> >> > >>> > by setting the variable as depending on whether type == BT_CLASS
> >> > >>> > or not. Sorry for the mistake.
> >> > >>> >
> >> > >>> >> > diff --git a/gcc/fortran/trans-decl.c b/gcc/fortran/trans-decl.c
> >> > >>> >> > index 3664824..e571a17 100644
> >> > >>> >> > --- a/gcc/fortran/trans-decl.c
> >> > >>> >> > +++ b/gcc/fortran/trans-decl.c
> >> > >>> >> > @@ -1013,16 +1017,24 @@ gfc_build_dummy_array_decl (gfc_symbol *
> >> > >>> >> > sym, tree dummy) tree decl;
> >> > >>> >> >    tree type;
> >> > >>> >> >    gfc_array_spec *as;
> >> > >>> >> > +  symbol_attribute *array_attr;
> >> > >>> >> >    char *name;
> >> > >>> >> >    gfc_packed packed;
> >> > >>> >> >    int n;
> >> > >>> >> >    bool known_size;
> >> > >>> >> >
> >> > >>> >> > -  if (sym->attr.pointer || sym->attr.allocatable
> >> > >>> >> > -      || (sym->as && sym->as->type == AS_ASSUMED_RANK))
> >> > >>> >> > +  /* Use the array as and attr.  */
> >> > >>> >> > +  as = sym->as;
> >> > >>> >> > +  array_attr = &sym->attr;
> >> > >>> >> > +
> >> > >>> >> > +  /* The pointer attribute is always set on a _data component,
> >> > >>> >> > therefore check
> >> > >>> >> > +     the sym's attribute only.  */
> >> > >>> >> > +  if (sym->attr.pointer || array_attr->allocatable
> >> > >>> >> > +      || (as && as->type == AS_ASSUMED_RANK))
> >> > >>> >> >      return dummy;
> >> > >>> >> >
> >> > >>> >> Any reason to sometimes use array_attr, sometimes not, like here?
> >> > >>> >> By the way, the comment is misleading: for classes, there is the
> >> > >>> >> class_pointer attribute (and it is a pain, I know).
> >> > >>> >
> >> > >>> > Yes, and a good one. Array_attr is sometimes sym->attr and
> >> > >>> > sometimes CLASS_DATA(sym)->attr aka
> >> > >>> > sym->ts.u.derived->components->attr. In the later case .pointer is
> >> > >>> > always set to 1 in the _data component's attr. I.e., the above if,
> >> > >>> > would always yield true for a class_array, which is not intended,
> >> > >>> > but rather destructive. I know about the class_pointer attribute,
> >> > >>> > but I figured, that it is not relevant here. Any idea how to
> >> > >>> > formulate the comment better, to reflect what I just explained?
> >> > >>> >
> >> > >>> > Regards,
> >> > >>> >         Andre
> >> > >>> > --
> >> > >>> > Andre Vehreschild * Email: vehre ad gmx dot de
> >> > >>> >
> >> > >>> >
> >> > >>> > ---------- Forwarded message ----------
> >> > >>> > From: Paul Richard Thomas <paul.richard.thomas@gmail.com>
> >> > >>> > To: Andre Vehreschild <vehre@gmx.de>, Dominique Dhumieres
> >> > >>> > <dominiq@lps.ens.fr> Cc:
> >> > >>> > Date: Sun, 22 Mar 2015 21:20:20 +0100
> >> > >>> > Subject: Bug in intrinsic LOC for scalar class objects
> >> > >>> > Dear Andre and Dominique,
> >> > >>> >
> >> > >>> > I have found that LOC is returning the address of the class
> >> > >>> > container rather than the _data component for class scalars. See
> >> > >>> > the source below, which you will recognise! A fix is attached.
> >> > >>> >
> >> > >>> > Note that the scalar allocate fails with MOLD= and so I substituted
> >> > >>> > SOURCE=.
> >> > >>> >
> >> > >>> > Cheers
> >> > >>> >
> >> > >>> > Paul
> >> > >>> >
> >> > >>> >     class(*), allocatable :: a(:), e ! Change 'e' to an array and
> >> > >>> > second memcpy works correctly
> >> > >>> >                                      ! Problem is with loc(e),
> >> > >>> > which returns the address of the
> >> > >>> >                                      ! class container.
> >> > >>> >     allocate (e, source = 99.0)
> >> > >>> >     allocate (a(2), source = [1.0, 2.0])
> >> > >>> >     call add_element_poly (a,e)
> >> > >>> >     select type (a)
> >> > >>> >       type is (real)
> >> > >>> >         print *, a
> >> > >>> >     end select
> >> > >>> >
> >> > >>> > contains
> >> > >>> >
> >> > >>> >     subroutine add_element_poly(a,e)
> >> > >>> >       use iso_c_binding
> >> > >>> >       class(*),allocatable,intent(inout),target :: a(:)
> >> > >>> >       class(*),intent(in),target :: e
> >> > >>> >       class(*),allocatable,target :: tmp(:)
> >> > >>> >       type(c_ptr) :: dummy
> >> > >>> >
> >> > >>> >       interface
> >> > >>> >         function memcpy(dest,src,n) bind(C,name="memcpy")
> >> > >>> > result(res) import
> >> > >>> >           type(c_ptr) :: res
> >> > >>> >           integer(c_intptr_t),value :: dest
> >> > >>> >           integer(c_intptr_t),value :: src
> >> > >>> >           integer(c_size_t),value :: n
> >> > >>> >         end function
> >> > >>> >       end interface
> >> > >>> >
> >> > >>> >       if (.not.allocated(a)) then
> >> > >>> >         allocate(a(1), source=e)
> >> > >>> >       else
> >> > >>> >         allocate(tmp(size(a)),source=a)
> >> > >>> >         deallocate(a)
> >> > >>> >         allocate(a(size(tmp)+1),source=e) ! mold gives a segfault
> >> > >>> >         dummy = memcpy(loc(a(1)),loc(tmp),sizeof(tmp))
> >> > >>> >         dummy = memcpy(loc(a(size(tmp)+1)),loc(e),sizeof(e))
> >> > >>> >       end if
> >> > >>> >     end subroutine
> >> > >>> > end
> >> > >>> >
> >> > >>>
> >> > >>>
> >> > >>>
> >> > >>
> >> > >>
> >> > >> --
> >> > >> Andre Vehreschild * Email: vehre ad gmx dot de
> >> > >
> >> > >
> >> > >
> >> > > --
> >> > > Outside of a dog, a book is a man's best friend. Inside of a dog it's
> >> > > too dark to read.
> >> > >
> >> > > Groucho Marx
> >> >
> >> >
> >> >
> >>
> >>
> >
> >
> > --
> > Andre Vehreschild * Email: vehre ad gmx dot de
> 
> 
> 


-- 
Andre Vehreschild * Email: vehre ad gmx dot de