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Re: [Bug fortran/32732] [Bind C] Character scalars are passed as arrays


hi Steve,

second, i think i've tracked down what was causing the problem with the
code snippet.  the call to sub0 gets converted (gfc_conv_function_call)
before the generate_local_decls runs for param_test.  this means that the
symbols for the dummy args in the call still say they're an array_type, so
the actuals given by sub0() are converted to array_type.  i think this
means that the fixup done for by-value character dummies in
generate_local_decl must also be done when mapping actuals to formals in
gfc_conv_function_call.  i've attached a patch that does this.  it's been
bootstrapped and regtested on x86 and x86_64 linux with no new failures,
but the real test is whether they'll work for you.  :-)

It doesn't look like it is working. I put in your patch (after removing the previous trans-decl.c patch) Then I rebuilt and tested my program and it still failed. Looking at the assembly language, there are still shifts of the characters in sub0 before it calls param_test so it looks like sub0 is still passing the arguments as arrays.

I am not sure why this is, I do hit the new code in trans-expr.c, before
calling gfc_conv_scalar_char_value I have:

<parm_decl 7d6cc2d8 my_char
   type <array_type 7d76e230
       type <integer_type 7d6d8150 char public unsigned string-flag QI
           size <integer_cst 7d6c51b8 constant invariant 8>
           unit size <integer_cst 7d6c51e0 constant invariant 1>
           align 8 symtab 0 alias set -1 canonical type 7d6d8150 precision 8 min <integer_cst 7d6c5208 0> max <integer_cst 7d6c5230 255>
           pointer_to_this <pointer_type 7d6e0690>>
       string-flag QI size <integer_cst 7d6c51b8 8> unit size <integer_cst 7d6c51e0 1>
       align 8 symtab 0 alias set -1 canonical type 7d76e230
       domain <integer_type 7d76e1c0 type <integer_type 7d6d8310 int4>
           SI
           size <integer_cst 7d6c53e8 constant invariant 32>
           unit size <integer_cst 7d6c50f0 constant invariant 4>
           align 32 symtab 0 alias set -1 canonical type 7d76e1c0 precision 32 min <integer_cst 7d6c5898 1> max <integer_cst 7d6c5898 1>>>
   readonly QI file x.f90 line 5 size <integer_cst 7d6c51b8 8> unit size <integer_cst 7d6c51e0 1>
   align 8 context <function_decl 7d76dd20 param_test> initial <array_type 7d76e230> arg-type <array_type 7d76e230> chain <parm_decl 7d6cc3a8 my_char_2>>

And after calling gfc_conv_scalar_char_value I have:

<parm_decl 7d6cc2d8 my_char
   type <integer_type 7d6d8150 char public unsigned string-flag QI
       size <integer_cst 7d6c51b8 constant invariant 8>
       unit size <integer_cst 7d6c51e0 constant invariant 1>
       align 8 symtab 0 alias set -1 canonical type 7d6d8150 precision 8 min <integer_cst 7d6c5208 0> max <integer_cst 7d6c5230 255>
       pointer_to_this <pointer_type 7d6e0690>>
   readonly QI file x.f90 line 5 size <integer_cst 7d6c51b8 8> unit size <integer_cst 7d6c51e0 1>
   align 8 context <function_decl 7d76dd20 param_test> initial <integer_type 7d6d8150 char> arg-type <integer_type 7d6d8150 char> chain <parm_decl 7d6cc3a8 my_char_2>>

But the arguments are still shifted before being passed from sub0 to
param_test.  I don't know why.


thanks for trying it out. i'm quite at a loss now as to why it's failing; i thought that fixing the array_type still being seen in gfc_conv_function_call would do it. now i'm not even sure where to start looking... the only thing i could think to do now is to run cc1 through gdb and figure out what the C frontend is doing with characters that isn't happening on the fortran side. it would be good to see the debug_tree output for the tree created by cc1, but that would be a bit more work for you. i'll see if i can figure out where to put the call to debug_tree and maybe pass it on to you.


thanks again for all of the help.
Chris


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