[Bug ada/65451] New: gnat bug: Storage_Error stack overflow or erroneous memory access

["gnugcc at marino dot st" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=65451

            Bug ID: 65451
           Summary: gnat bug: Storage_Error stack overflow or erroneous
                    memory access
           Product: gcc
           Version: unknown
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ada
          Assignee: unassigned at gcc dot gnu.org
          Reporter: gnugcc at marino dot st
              Host: x86_64-unknown-dragonfly4.1
            Target: x86_64-unknown-dragonfly4.1
             Build: x86_64-unknown-dragonfly4.1

I was testing the latest gcc-5 snapshot against FreeBSD Ada ports (which
DragonFly uses).  I am seeing an intermittent "GNAT BUG" error on the Matreshka
port ( http://freshports/devel/matreshka ):

ada -c -fPIC -g -gnatwa -gnat12 -gnatW8 -O2 -gnatn
matreshka-internals-strings.adb
+===========================GNAT BUG DETECTED==============================+
| 5.0.0 20150315 (experimental) -=> GNAT AUX [DragonFly64]
(x86_64-aux-dragonfly4.1) |
| Storage_Error stack overflow or erroneous memory access                  |
| Error detected at matreshka-internals-utf16.adb:45:33                    |
| Please submit a bug report; see http://gcc.gnu.org/bugs.html.            |
| Use a subject line meaningful to you and us to track the bug.            |
| Include the entire contents of this bug box in the report.               |
| Include the exact command that you entered.                              |
| Also include sources listed below.                                       |
+==========================================================================+

Please include these source files with error report
Note that list may not be accurate in some cases,
so please double check that the problem can still
be reproduced with the set of files listed.
Consider also -gnatd.n switch (see debug.adb).

/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka-internals-strings.adb
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka-internals-strings.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka-internals.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/league.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka-atomics.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka-atomics-counters.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka-internals-unicode.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka-internals-unicode-ucd.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka-internals-utf16.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka-atomics-generic_test_and_set.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka-internals-strings-configuration__x86_64.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka-internals-strings-handlers.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/arch/x86_64/matreshka-internals-strings-handlers-x86_64.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka-internals-strings-handlers-portable.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/arch/x86_generic/matreshka-internals-strings-handlers-generic_x86_sse2.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/arch/x86_generic/matreshka-internals-strings-handlers-x86_utilities.ads
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka-atomics-generic_test_and_set__gcc__64.adb
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka-atomics-counters__gcc.adb
/wrkdirs/devel/matreshka/work/matreshka-0.6.0/source/league/matreshka-internals-utf16.adb

compilation abandoned
gprbuild: *** compilation phase failed
Makefile.build:36: recipe for target 'league' failed
gmake[2]: *** [league] Error 4
gmake[2]: Leaving directory '/wrkdirs/devel/matreshka/work/matreshka-0.6.0'
Makefile:21: recipe for target 'all' failed
gmake[1]: *** [all] Error 2
gmake[1]: Leaving directory '/wrkdirs/devel/matreshka/work/matreshka-0.6.0'
*** Error code 1

I suspect this isn't enough information to diagnose anything.  The link to the
source is found on the freshports site, and some patches are in the svn repo. 
There are an additional three patches that I was testing that are needed to
build on gcc-5 (e.g. missing explicit "limited" keyword patch)

I just want to get this documented for now.  Let me know what I can provide to
help troubleshoot it.