[Bug fortran/30180] New: FAIL: gdb.fortran/module.exp: print var_d

[Bug fortran/30180] New: FAIL: gdb.fortran/module.exp: print var_d

[vries at gcc dot gnu.org]

https://sourceware.org/bugzilla/show_bug.cgi?id=30180

            Bug ID: 30180
           Summary: FAIL: gdb.fortran/module.exp: print var_d
           Product: gdb
           Version: HEAD
            Status: NEW
          Severity: normal
          Priority: P2
         Component: fortran
          Assignee: unassigned at sourceware dot org
          Reporter: vries at gcc dot gnu.org
  Target Milestone: ---

On powerpc64le-linux (centos 7, with gcc 4.8.5), I run into:
...
(gdb) PASS: gdb.fortran/module.exp: print var_c
print var_d^M
Missing ELF symbol "var_d".^M
(gdb) FAIL: gdb.fortran/module.exp: print var_d
...

Looking at the debuginfo, we have an imported_declaration:
...
 <2><19b>: Abbrev Number: 12 (DW_TAG_imported_declaration)
    <19c>   DW_AT_decl_file   : 1
    <19d>   DW_AT_decl_line   : 59
    <19e>   DW_AT_name        : var_d
    <1a2>   DW_AT_import      : <0x20b> [Abbrev Number: 14 (DW_TAG_variable)]
...
referring to a declaration:
...
 <2><20b>: Abbrev Number: 14 (DW_TAG_variable)
    <20c>   DW_AT_name        : var_c
    <210>   DW_AT_decl_file   : 1
    <211>   DW_AT_decl_line   : 33
    <212>   DW_AT_linkage_name: __modmany_MOD_var_c
    <216>   DW_AT_type        : <0x60>
    <21a>   DW_AT_external    : 1
    <21a>   DW_AT_declaration : 1
...

In contrast, on x86_64-linux (openSUSE Leap 15.4, with gcc 7.5.0), I have:
...
(gdb) PASS: gdb.fortran/module.exp: print var_c
print var_d^M
$8 = 12^M
(gdb) PASS: gdb.fortran/module.exp: print var_d
...
with debuginfo also mentioning an imported_declaration:
...
 <2><2df>: Abbrev Number: 12 (DW_TAG_imported_declaration)
    <2e0>   DW_AT_decl_file   : 1
    <2e1>   DW_AT_decl_line   : 59
    <2e2>   DW_AT_name        : var_d
    <2e6>   DW_AT_import      : <0x1b7> [Abbrev Number: 3 (DW_TAG_variable)]
...
but referring to a definition, with location attribute:
...
 <2><1b7>: Abbrev Number: 3 (DW_TAG_variable)
    <1b8>   DW_AT_name        : var_c
    <1bc>   DW_AT_decl_file   : 1
    <1bd>   DW_AT_decl_line   : 33
    <1be>   DW_AT_linkage_name: __modmany_MOD_var_c
    <1c2>   DW_AT_type        : <0xf2>
    <1c6>   DW_AT_external    : 1
    <1c6>   DW_AT_location    : 9 byte block: 3 44 20 40 0 0 0 0 0
                                (DW_OP_addr: 402044)
...

So, I'd classify this as a testsuite issue and xfail it for some compiler
versions, but I wonder.  We have this trick in gdb where we combine a decl with
a minimal symbol in order to get the location, so why doesn't this work?  Is
this not enabled for fortran?

The minimal symbol seems to be there:
...
$ nm  outputs/gdb.fortran/module/module | grep __modmany_MOD_var_c
0000000010020058 D __modmany_MOD_var_c
...
so it could work.

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