[PATCH 15/18] testsuite, fortran: allow additional completions in module.exp

[Nils-Christian Kempke via Gdb-patches <gdb-patches@sourceware.org>]

For ifort, ifx, and flang the tests "complete modm" and "complete
modmany" fail.  This is because all three emit additional completion
suggestions.  These additional suggestions have their origin in symbols
emitted by the compilers which can also be completed from the respective
incomplete word (modm or modmany).  For this specific example gfortran
does not emit any additional symbols.

For example, in this test the linkage name for var_a in ifx is
"modmany_mp_var_a_" while gfortran uses "__modmany_MOD_var_a" instead.
Since modmany_mp_var_a can be completed from modm and also modmany they
will get displayed, while gfortran's symbol starts with "__" and thus will
be ignored (it cannot be a completion of a word starting with "m").

Similar things happen in flang and ifort.  Some example output is shown
below:

FLANG
  (gdb) complete p modm
  p modmany
  p modmany::var_a
  p modmany::var_b
  p modmany::var_c
  p modmany::var_i
  p modmany_

IFX/IFORT
  (gdb) complete p modm
  p modmany
  p modmany._
  p modmany::var_a
  p modmany::var_b
  p modmany::var_c
  p modmany::var_i
  p modmany_mp_var_a_
  p modmany_mp_var_b_
  p modmany_mp_var_c_
  p modmany_mp_var_i_

GFORTRAN
  (gdb) complete p modm
  p modmany
  p modmany::var_a
  p modmany::var_b
  p modmany::var_c
  p modmany::var_i

I want to emphasize: for Fortran (and also C/C++) the complete command
does not actually check whether its suggestions make sense - all it does
is look for any symbol (in the minimal symbols, partial symbols etc.)
that a given substring can be completed to (meaning that the given substring
is the beginning of the symbol).  One can easily produce a similar
output for the gfortran compiled executable.  For this look at the
slightly modified "complete p mod" in gfortran:

  (gdb) complete p mod
  p mod1
  p mod1::var_const
  ...
  p mod_1.c
  p modcounter
  p mode_t
  p modf
  ...
  p modify_ldt
  p modmany
  p modmany::var_a
  p modmany::var_b
  p modmany::var_c
  p modmany::var_i
  p module
  p module.f90
  p module_entry
  p moduse
  p moduse::var_x
  p moduse::var_y

Many of the displayed symbols do not actually work with print:

  (gdb) p mode_t
  Attempt to use a type name as an expression
  (gdb) p mod_1.c
  No symbol "mod_1" in current context.
  (gdb)

I think that in the given test the output for gfortran only looks nice
"by chance" rather than is actually expected.  Expected is any output
that also contains the completions

  p modmany

  p modmany::var_a
  p modmany::var_b
  p modmany::var_c
  p modmany::var_i

while anythings else can be displayed as well (depending on the
compiler and its emitted symbols).

This, I'd consider all three outputs as valid and expected - one is just
somewhat lucky that gfortran does not produce any additional symbols that
got matched.

The given patch improves test performance for all three compilers
by allowing additional suggested completions inbetween and after
the two given blocks in the test.  I did not allow additional print
within the modmany_list block since the output is ordered alphabetically
and there should normally not appear any additional symbols there.

For flang/ifx/ifort I each see 2 failures less (which are exactly the two
complete tests).

As a side note and since I mentioned C++ in the beginning: I also tried
the gdb.cp/completion.exp.  The output seems a bit more reasonable,
mainly since C++ actually has a demangler in place and linkage symbols
do not appear in the output of complete.  Still, with a poor enough
to-be-completed string one can easily produce similar results:

  (gdb) complete p t
  ...
  p typeinfo name for void
  p typeinfo name for void const*
  p typeinfo name for void*
  p typeinfo name for wchar_t
  p typeinfo name for wchar_t const*
  p typeinfo name for wchar_t*
  p t *** List may be truncated, max-completions reached. ***
  (gdb) p typeinfo name for void*
  No symbol "typeinfo" in current context.
  (gdb) complete p B
  p BACK_SLASH
  p BUF_FIRST
  p BUF_LAST
  ...
  p Base
  p Base::Base()
  p Base::get_foo()
  p bad_key_err
  p buf
  p buffer
  p buffer_size
  p buflen
  p bufsize
  p build_charclass.isra
  (gdb) p bad_key_err
  No symbol "bad_key_err" in current context.

(compiled with gcc/g++ and breaking at main).

This patch is only about making the referenced test more 'fair' for the
other compilers.  Generally, I find the behavior of complete a bit
confusing and maybe one wants to change this at some point but this
would be a bigger task.
---
 gdb/testsuite/gdb.fortran/module.exp | 5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/gdb/testsuite/gdb.fortran/module.exp b/gdb/testsuite/gdb.fortran/module.exp
index b00122a037..1895a20079 100644
--- a/gdb/testsuite/gdb.fortran/module.exp
+++ b/gdb/testsuite/gdb.fortran/module.exp
@@ -118,9 +118,10 @@ gdb_test "print var_z" " = 31" "print var_x value 31"
 gdb_test "ptype modmany" "type = module modmany"
 
 proc complete {expr list} {
+    set n_lines "\(?:\\r\\n.*\)*"
     set cmd "complete p $expr"
-    set expect [join [concat [list $cmd] $list] "\r\np "]
-    gdb_test $cmd $expect "complete $expr"
+    set expect [join [concat [list $cmd] $list] $n_lines]
+    gdb_test $cmd "$expect$n_lines" "complete $expr"
 }
 set modmany_list {modmany::var_a modmany::var_b modmany::var_c modmany::var_i}
 complete "modm" "modmany $modmany_list"
-- 
2.25.1

Intel Deutschland GmbH
Registered Address: Am Campeon 10, 85579 Neubiberg, Germany
Tel: +49 89 99 8853-0, www.intel.de <http://www.intel.de>
Managing Directors: Christin Eisenschmid, Sharon Heck, Tiffany Doon Silva  
Chairperson of the Supervisory Board: Nicole Lau
Registered Office: Munich
Commercial Register: Amtsgericht Muenchen HRB 186928