[Bug fortran/54603] New: Wrong code woth structure constructor for proc-pointer components

[burnus at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54603

             Bug #: 54603
           Summary: Wrong code woth structure constructor for proc-pointer
                    components
    Classification: Unclassified
           Product: gcc
           Version: 4.8.0
            Status: UNCONFIRMED
          Keywords: ice-on-valid-code, wrong-code
          Severity: normal
          Priority: P3
         Component: fortran
        AssignedTo: unassig...@gcc.gnu.org
        ReportedBy: bur...@gcc.gnu.org
                CC: ja...@gcc.gnu.org, xarthisius...@gmail.com


Created attachment 28202
  --> http://gcc.gnu.org/bugzilla/attachment.cgi?id=28202
Test case

Reported by Kacper Kowalik via IRC.


Fortran 2003 (and 2008) allow to initialize procedure-pointer components via
the structure constructor, quoting F2003:

"R459  component-data-source  is  expr  or  data-target  or  proc-target"

And the latter can be per R742 and
"C726   A procedure-name shall be the name of ... or a procedure pointer"


I assume we either take a pointer reference too much or too little, leading to
both wrong code and an ICE, depending whether we pass the name of a procedure
or a procedure pointer.


For
      this%a = ext_ptr(init, cleanup)
      this%a%init => init

gfortran generates

    ext_ptr.0.init = (void (*<T4b4>) (void)) init;
    ext_ptr.0.cleanup = (void (*<T4b4>) (void)) cleanup;
    this->_data->a = ext_ptr.0;

  this->_data->a.init = *init;

Note the missing "*" in the failing declaration.



While using proc-pointers in the initialization
  this%a = ext_ptr(this%a%init,this%a%cleanup)
gives an ICE in fold_convert_loc, bei fold-const.c:1880


The backtrace shows:

#0  fold_convert_loc (loc=0, type=0x2aaaac29f1f8, arg=<optimized out>) at
gcc/fold-const.c:1880
#1  0x000000000063406b in gfc_trans_scalar_assign
(lse=lse@entry=0x7fffffffcd70, rse=rse@entry=0x7fffffffcd20, ts=...,
l_is_temp=l_is_temp@entry=true, 
    deep_copy=deep_copy@entry=false, dealloc=dealloc@entry=true) at
/home/tobgcc/fortran/trans-expr.c:6427
#2  0x00000000006359b8 in gfc_trans_subcomponent_assign (expr=0x15e9210,
cm=0x15e37e0, dest=0x2aaaac27c0e0) at gcc/fortran/trans-expr.c:5588
#3  gfc_trans_structure_assign (dest=0x2aaaac295be0, expr=<error reading
variable: Unhandled dwarf expression opcode 0xfa>, 
    expr=<error reading variable: Unhandled dwarf expression opcode 0xfa>) at
gcc/fortran/trans-expr.c:5635