Ok something I have gotten to work, but only doing things by hand in petscvecmod.F90:

diff --git a/src/vec/f90-mod/petscvecmod.F90 b/src/vec/f90-mod/petscvecmod.F90
index 0c447156b9..ef3e2e2e55 100644
--- a/src/vec/f90-mod/petscvecmod.F90
+++ b/src/vec/f90-mod/petscvecmod.F90
 module petscisdef
 use petscisdefdummy
 interface operator(.ne.)
 function isnotequal(A,B)
-  use petscisdefdummy
+ import tIS
   logical isnotequal                                                                     
   type(tIS), intent(in) :: A,B
 end function isnotequal

This works for everything wrapped in a module which contains an interface block. For dangling functions the following works:

 function isnotequal(A,B)
-  use petscisdefdummy
+ use petscisdef, only: tIs
   logical isnotequal
   type(tIS), intent(in) :: A,B
   isnotequal = (A%v .ne. B%v)
 end function isnotequal

Do our fortran stub generators have any notion of types? Specifically types that originate from petsc?

Best regards,

Jacob Faibussowitsch
(Jacob Fai - booss - oh - vitch)
Cell: (312) 694-3391

On Mar 16, 2021, at 11:11, Satish Balay <balay@mcs.anl.gov> wrote:

On Tue, 16 Mar 2021, Jacob Faibussowitsch wrote:

My [partial] change is in branch balay/reorg-f90-for-xlf

Satish is this branch pushed? I’d like to send it to the ibm folks to see if it works for them as well.

Sorry - pushed now. From what I remember - it didn't work.

Satish


They also added this extra follow up:

The change we did in the source files is to replace all the "use pet*" statements in all the Interface blocks with IMPORT statement.

The nature of this workaround is to reduce the number of symbols that the compiler have to create, which exceeded the limitation and caused ICE.

Every USE statement in an interface block opens up the module symbol file and reads all the symbols from it and creates an entity for each symbol in compiler. This is unnecessary when the module already has the same USE statement in the module scope. Instead, users can use IMPORT statement to make the module symbols accessible inside interface face blocks.

With the change, the compiler would only read the module symbol file once and create one set of symbols where the old code reads the module symbol files as many times as the number of the USE statements in Interface blocks and create that many sets of duplicate symbols. Replacing those USE statements with IMPORT statements also shortens the compile time significantly.

Best regards,

Jacob Faibussowitsch
(Jacob Fai - booss - oh - vitch)
Cell: (312) 694-3391

On Mar 3, 2021, at 13:43, Satish Balay via petsc-dev <petsc-dev@mcs.anl.gov> wrote:

The only change I can get working (i.e avoid compile errors) is to split petscvecmod.F90 into 2 source files - but I don't know if this will help with xlf..

My [partial] change is in branch balay/reorg-f90-for-xlf

Satish

On Wed, 3 Mar 2021, Satish Balay via petsc-dev wrote:

On Wed, 3 Mar 2021, Satish Balay via petsc-dev wrote:

Sure - once any change works locally [for gcc and xlf]

When I try - I get a bunch of errors.. [yet to digest them.]

Can you please give the following source code workaround a try?
Since there is already "use petscvecdefdummy" at the module scope, one workaround might be to remove the unnecessary "use petscvecdefdummy" in vecnotequal and vecequals
and all similar procedures.

For example, the test case has:
     module petscvecdef
     use petscvecdefdummy
...
     function vecnotequal(A,B)
       use petscvecdefdummy
       logical vecnotequal
       type(tVec), intent(in) :: A,B
       vecnotequal = (A%v .ne. B%v)
     end function


Ok - try this suggestion:

diff --git a/src/vec/f90-mod/petscvecmod.F90 b/src/vec/f90-mod/petscvecmod.F90
index 0c447156b9..81968c7ca1 100644
--- a/src/vec/f90-mod/petscvecmod.F90
+++ b/src/vec/f90-mod/petscvecmod.F90
@@ -77,7 +77,6 @@
       use petscvecdefdummy
       interface operator(.ne.)
         function vecnotequal(A,B)
-            use petscvecdefdummy
           logical vecnotequal
           type(tVec), intent(in) :: A,B
         end function



        FC arch-linux-c-debug/obj/vec/f90-mod/petscvecmod.o
/home/balay/petsc/src/vec/f90-mod/petscvecmod.F90:81:22:

 81 |             type(tVec), intent(in) :: A,B
    |                      1
Error: Derived type ‘tvec’ at (1) is being used before it is defined
/home/balay/petsc/include/../src/vec/f90-mod/ftn-auto-interfaces/petscis.h90:2:10:

  2 |       use petscvecdef
    |          1
Fatal Error: Cannot open module file ‘petscvecdef.mod’ for reading at (1): No such file or directory
<<<<<<

Satish