fortran: Fix arrays of variable length strings for FORTRAN

Before this change resolve_dynamic_array_or_string was called for
all TYPE_CODE_ARRAY and TYPE_CODE_STRING types, but, in the end,
this function always called create_array_type_with_stride, which
creates a TYPE_CODE_ARRAY type.

Suppose we have

subroutine vla_array (arr1, arr2)
  character (len=*):: arr1 (:)
  character (len=5):: arr2 (:)

  print *, arr1 ! break-here
  print *, arr2
end subroutine vla_array

The "print arr1" and "print arr2" command at the "break-here" line
gives the following output:

(gdb) print arr1
$1 = <incomplete type>
(gdb) print arr2
$2 = ('abcde', 'abcde', 'abcde')
(gdb) ptype arr1
type = Type
End Type
(gdb) ptype arr2
type = character*5 (3)

Dwarf info using Intel® Fortran Compiler for such case contains following:
 <1><fd>: Abbrev Number: 12 (DW_TAG_string_type)
    <fe>   DW_AT_name        : (indirect string, offset: 0xd2): .str.ARR1
    <102>   DW_AT_string_length: 3 byte block: 97 23 8 (DW_OP_push_object_address; DW_OP_plus_uconst: 8)

After this change resolve_dynamic_array_or_string now calls
create_array_type_with_stride or create_string_type, so if the
incoming dynamic type is a TYPE_CODE_STRING then we'll get back a
TYPE_CODE_STRING type.  Now gdb shows following:

(gdb) p arr1
$1 = ('abddefghij', 'abddefghij', 'abddefghij', 'abddefghij', 'abddefghij')
(gdb) p arr2
$2 = ('abcde', 'abcde', 'abcde')
(gdb) ptype arr1
type = character*10 (5)
(gdb) ptype arr2
type = character*5 (3)

In case of GFortran, compiler emits DW_TAG_structure_type for string type
arguments of the subroutine and it has only DW_AT_declaration tag.  This
results in <incomplete type> in gdb.  So, following issue is raised in gcc
bugzilla "https://gcc.gnu.org/bugzilla/show_bug.cgi?id=101826".

Fixing above issue introduce regression in gdb.fortran/mixed-lang-stack.exp,
i.e. the test forces the language to C/C++ and print a Fortran string value.
The string value is a dynamic type with code TYPE_CODE_STRING.

Before this commit the dynamic type resolution would always convert this to
a TYPE_CODE_ARRAY of characters, which the C value printing could handle.

But now after this commit we get a TYPE_CODE_STRING, which
neither the C value printing, or the generic value printing code can
support.  And so, I've added support for TYPE_CODE_STRING to the generic
value printing, all characters of strings are printed together till the
first null character.

Lastly, in gdb.opt/fortran-string.exp and gdb.fortran/string-types.exp
tests it expects type of character array in 'character (3)' format but now
after this change we get 'character*3', so tests are updated accordingly.

Approved-By: Tom Tromey <tom@tromey.com>

0 files changed, 0 insertions, 0 deletions