Make the Ada programming language available on GNU/Hurd in its GCC GNAT implementation, and enable Hurd-specific features.

There is a FOSS Factory bounty (p259) on this task.

Part I

First, make the language functional, have its test suite pass without errors.

Using, for example, the build instructions from GCC, you'll need to add ada to --enable-languages.

Original GSoC Task Description

Debian GCC

There has a patch been added for GNU/kFreeBSD: bfe081336914729fc0180c07ab4afa41965100f2, `git-svn-id: svn://svn.debian.org/gcccvs/branches/sid@5638 6ca36cf4-e1d1-0310-8c6f-e303bb2178ca'

IRC, freenode, #hurd, 2012-07-17

<gnu_srs> I've found the remaining problem with gnat backtrace for Hurd!
  Related to the stack frame.
<gnu_srs> This version does not work: one relying on static assumptions
  about the frame layout
<gnu_srs> Causing segfaults.
<gnu_srs> Any interest to create a test case out of that piece of code,
  taken from gcc/ada/tracebak.c?
<braunr> gnu_srs: sure

IRC, freenode, #hurd, 2012-07-18

<braunr> "Digging further revealed that the GNU/Hurd stack frame does not
  seem to
<braunr> be static enough to define USE_GENERIC_UNWINDER in
  gcc/ada/tracebak.c.
<braunr> "
<braunr> what do you mean by a "stack frame does not seem to be static
  enough" ?
<gnu_srs> I can qoute from the source file if you want. Otherwise look at
  the code yourself: gcc/ada/tracebak,c
<gnu_srs> I mean that something is wrong with the stack frame for
  Hurd. This is the code I wanted to use as a test case for the stack.
<gnu_srs> Remember?
<braunr> more or less
<braunr> ah, "static assumptions"
<braunr> all right, i don't think anything is "wrong" with stack frames
<braunr> but if you use a recent version of gcc, as indicated in the code,
  -fomit-frame-pointer is enabled by default
<braunr> so your stack frame won't look like it used to be without the
  option
<braunr> hence the need for USE_GCC_UNWINDER
<braunr> http://en.wikipedia.org/wiki/Call_stack explains this very well
<gnu_srs> However, kfreebsd does not seem to need USE_GCC_UNWINDER, how
  come?
<braunr> i guess they don't omit the frame pointer
<braunr> your fix is good btw
<gnu_srs> thanks

IRC, freenode, #hurd, 2012-07-19

<gnu_srs> tschwinge: The bug in #681998 should go upstream. Applied in
  Debian already. Hopefully this is the last patch needed for the port of
  GNAT to Hurd.

2015-11-27

Is this related to:

gcc/ada/tracebak.c:

#if (defined (__x86_64__) || defined (__linux__)) && !defined (__USING_SJLJ_EXCEPTIONS__)
#define USE_GCC_UNWINDER
#else
#define USE_GENERIC_UNWINDER

Svante's patch

A basic port has been done by Svante, Debian bug #668425, Debian bug #681998, id:"1333104917.2962.439.camel@s1499.it.kth.se", but there's still lots of work remaining. The port is not yet upstream: the maintainer raised some concerns that I have not yet found the time to follow up on, id:"1339857758-5032-1-git-send-email-thomas@codesourcery.com". While the test results of the GCC/GNAT testsuite don't look bad (but there are a few unresolved issues, and the testsuite appears to be a rather small one), I don't know if the port has yet seen any real-world usage, such as using it for any bigger Ada code bases, or any Ada testsuites.

"try2"

id:"1456875776.5852.194.camel@gmail.com". GCC trunk r234252. gcc/ada/s-osinte-gnu.adb: r235467 (on trunk)/r235468 (on gcc-6-branch). getpagesize patch: r235896 (on trunk)/r235897 (on gcc-6-branch). Still incomplete? (Changes to generic files?)

2016-12-14

Based on commit 17f0f5acdcfb9181203ca9b6d8f8cbc64e5ce843, tschwinge tried to build with --enable-languages=all,ada, but both with --disable-bootstrap and --enable-bootstrap we run into:

[...]
make[3]: Entering directory '/media/erich/home/thomas/tmp/gcc/hurd/master.build/gcc/ada/tools'
../../gnatbind -I- -I../rts -I. -I/home/thomas/tmp/gcc/hurd/master/gcc/ada -o b_gnatm.adb gnatmake.ali
error: "system.ads" has restriction No_Implicit_Dynamic_Code
error: but the following files violate this restriction:
error:   "make.adb"
error:   "makeutl.adb"
error:   "prj.adb"
error:   "prj-env.adb"
error:   "prj-conf.adb"
error:   "prj-nmsc.adb"
../gcc-interface/Makefile:2987: recipe for target 'b_gnatm.adb' failed
make[3]: *** [b_gnatm.adb] Error 5
make[3]: Leaving directory '/media/erich/home/thomas/tmp/gcc/hurd/master.build/gcc/ada/tools'
Makefile:194: recipe for target 'gnattools-native' failed
make[2]: *** [gnattools-native] Error 2
make[2]: Leaving directory '/media/erich/home/thomas/tmp/gcc/hurd/master.build/gnattools'
Makefile:9650: recipe for target 'all-gnattools' failed
make[1]: *** [all-gnattools] Error 2
make[1]: Leaving directory '/media/erich/home/thomas/tmp/gcc/hurd/master.build'
Makefile:895: recipe for target 'all' failed
make: *** [all] Error 2

(Partial) review of differences:

gcc/ada/gcc-interface/Makefile.in, Linux vs. Hurd

LIBGNAT_TARGET_PAIRS = \
  a-intnam.ads<a-intnam-linux.ads vs. a-intnam.ads<a-intnam-freebsd.ads
  a-synbar.adb<a-synbar-posix.adb vs. nil
  a-synbar.ads<a-synbar-posix.ads vs. nil
  s-inmaop.adb<s-inmaop-posix.adb
  s-intman.adb<s-intman-posix.adb
  s-tpopsp.adb<s-tpopsp-tls.adb vs. s-tpopsp.adb<s-tpopsp-posix-foreign.adb
  g-sercom.adb<g-sercom-linux.adb vs. nil
  a-exetim.adb<a-exetim-posix.adb vs. nil
  a-exetim.ads<a-exetim-default.ads vs. nil
  s-linux.ads<s-linux.ads vs. nil
  s-osinte.adb<s-osinte-posix.adb vs. s-osinte.adb<s-osinte-gnu.adb
  $(ATOMICS_TARGET_PAIRS)
  system.ads<system-linux-x86.ads vs. system.ads<system-freebsd-x86.ads
  $(X86_TARGET_PAIRS)
  s-mudido.adb<s-mudido-affinity.adb vs. nil
  s-osinte.ads<s-osinte-linux.ads vs. s-osinte.ads<s-osinte-gnu.ads
  s-osprim.adb<s-osprim-posix.adb
  s-taprop.adb<s-taprop-linux.adb vs. s-taprop.adb<s-taprop-posix.adb
  s-tasinf.ads<s-tasinf-linux.ads vs. nil
  s-tasinf.adb<s-tasinf-linux.adb vs. nil
  s-taspri.ads<s-taspri-posix.ads

EH_MECHANISM=-gcc
THREADSLIB = -lpthread -lrt vs. THREADSLIB = -lpthread
EXTRA_GNATRTL_NONTASKING_OBJS += g-sse.o g-ssvety.o
EXTRA_GNATRTL_TASKING_OBJS=s-linux.o a-exetim.o vs. nil

TOOLS_TARGET_PAIRS = \
  mlib-tgt-specific.adb<mlib-tgt-specific-linux.adb
  indepsw.adb<indepsw-gnu.adb

GNATLIB_SHARED = gnatlib-shared-dual
MISCLIB = -ldl vs. nil
GMEM_LIB = gmemlib
LIBRARY_VERSION := $(LIB_VERSION)

TOOLS1_LIBS=-ldl vs. nil

Eventually tschwinge found http://gcc.gnu.org/PR57188, and similarly fixed the issue.

getcontext/makecontext/setcontext/swapcontext usage analysis

In context of tls-threadvar. Looking at GCC trunk commit f6568ea476aa52a6e23c6db43b3e240cde55783a (2013-04-26).

gcc/ada/init.c:  sigaltstack (&stack, NULL);
gcc/ada/init.c:      sigaltstack (&stack, NULL);
gcc/ada/init.c:  sigaltstack (&stack, NULL);
gcc/ada/s-osinte-aix.ads:   function sigaltstack
gcc/ada/s-osinte-aix.ads:   pragma Import (C, sigaltstack, "sigaltstack");
gcc/ada/s-osinte-android.ads:   function sigaltstack
gcc/ada/s-osinte-android.ads:   pragma Import (C, sigaltstack, "sigaltstack");
gcc/ada/s-osinte-darwin.ads:   function sigaltstack
gcc/ada/s-osinte-darwin.ads:   pragma Import (C, sigaltstack, "sigaltstack");
gcc/ada/s-osinte-freebsd.ads:   function sigaltstack
gcc/ada/s-osinte-freebsd.ads:   pragma Import (C, sigaltstack, "sigaltstack");
gcc/ada/s-osinte-hpux.ads:   function sigaltstack
gcc/ada/s-osinte-hpux.ads:   pragma Import (C, sigaltstack, "sigaltstack");
gcc/ada/s-osinte-kfreebsd-gnu.ads:   function sigaltstack
gcc/ada/s-osinte-kfreebsd-gnu.ads:   pragma Import (C, sigaltstack, "sigaltstack");
gcc/ada/s-osinte-linux.ads:   function sigaltstack
gcc/ada/s-osinte-linux.ads:   pragma Import (C, sigaltstack, "sigaltstack");
gcc/ada/s-osinte-rtems.adb:   -- sigaltstack --
gcc/ada/s-osinte-rtems.adb:   function sigaltstack
gcc/ada/s-osinte-rtems.adb:   end sigaltstack;
gcc/ada/s-osinte-rtems.ads:   function sigaltstack
gcc/ada/s-osinte-solaris-posix.ads:   function sigaltstack
gcc/ada/s-osinte-solaris-posix.ads:   pragma Import (C, sigaltstack, "sigaltstack");
gcc/ada/s-taprop-linux.adb:            Result := sigaltstack (Stack'Access, null);
gcc/ada/s-taprop-posix.adb:            Result := sigaltstack (Stack'Access, null);
gcc/ada/init.c:  stack.ss_sp = __gnat_alternate_stack;
gcc/ada/init.c:      stack.ss_sp = __gnat_alternate_stack;
gcc/ada/init.c:  stack.ss_sp = __gnat_alternate_stack;
gcc/ada/s-osinte-aix.ads:      ss_sp    : System.Address;
gcc/ada/s-osinte-android.ads:      ss_sp    : System.Address;
gcc/ada/s-osinte-darwin.ads:      ss_sp    : System.Address;
gcc/ada/s-osinte-darwin.ads:      uc_stack    : stack_t;          --  Stack Used By This Context
gcc/ada/s-osinte-freebsd.ads:      ss_sp    : System.Address;
gcc/ada/s-osinte-hpux.ads:      ss_sp    : System.Address;
gcc/ada/s-osinte-kfreebsd-gnu.ads:      ss_sp    : System.Address;
gcc/ada/s-osinte-linux.ads:      ss_sp    : System.Address;
gcc/ada/s-osinte-rtems.ads:      ss_sp    : System.Address;
gcc/ada/s-osinte-solaris-posix.ads:      ss_sp    : System.Address;
gcc/ada/s-osinte-solaris.ads:      ss_sp        : System.Address;
gcc/ada/s-osinte-solaris.ads:      uc_stack     : record_type_2;
gcc/ada/s-taprop-linux.adb:            Stack.ss_sp    := Self_ID.Common.Task_Alternate_Stack;
gcc/ada/s-taprop-posix.adb:            Stack.ss_sp    := Self_ID.Common.Task_Alternate_Stack;

gcc/ada/init.c:  act.sa_flags |= SA_ONSTACK;
gcc/ada/init.c:      act.sa_flags |= SA_ONSTACK;
gcc/ada/init.c:  act.sa_flags = SA_SIGINFO | SA_ONSTACK;
gcc/ada/init.c:  act.sa_flags |= SA_ONSTACK;
gcc/ada/s-intman-posix.adb:                  act.sa_flags := act.sa_flags + SA_ONSTACK;
gcc/ada/s-linux-alpha.ads:   SA_ONSTACK  : constant := 16#01#;
gcc/ada/s-linux-hppa.ads:   SA_ONSTACK : constant := 16#01#;
gcc/ada/s-linux-mipsel.ads:   SA_ONSTACK  : constant := 16#08000000#;
gcc/ada/s-linux-sparc.ads:   SA_ONSTACK  : constant := 16#001#;
gcc/ada/s-linux.ads:   SA_ONSTACK  : constant := 16#08000000#;
gcc/ada/s-osinte-aix.ads:   SA_ONSTACK : constant := 16#0001#;
gcc/ada/s-osinte-android.ads:   SA_ONSTACK : constant := System.Linux.SA_ONSTACK;
gcc/ada/s-osinte-darwin.ads:   SA_ONSTACK : constant := 16#0001#;
gcc/ada/s-osinte-freebsd.ads:   SA_ONSTACK : constant := 16#0001#;
gcc/ada/s-osinte-hpux-dce.ads:   SA_ONSTACK  : constant  := 16#01#;
gcc/ada/s-osinte-hpux.ads:   SA_ONSTACK : constant := 16#01#;
gcc/ada/s-osinte-kfreebsd-gnu.ads:   SA_ONSTACK : constant := 16#0001#;
gcc/ada/s-osinte-linux.ads:   SA_ONSTACK : constant := System.Linux.SA_ONSTACK;
gcc/ada/s-osinte-lynxos.ads:   SA_ONSTACK : constant := 16#00#;
gcc/ada/s-osinte-lynxos.ads:   --  SA_ONSTACK is not defined on LynxOS, but it is referred to in the POSIX
gcc/ada/s-osinte-rtems.ads:   SA_ONSTACK : constant := 16#00#;
gcc/ada/s-osinte-rtems.ads:   --  SA_ONSTACK is not defined on RTEMS, but it is referred to in the POSIX
gcc/ada/s-osinte-solaris-posix.ads:   SA_ONSTACK : constant := 16#0001#;
gcc/ada/s-osinte-vxworks.ads:   SA_ONSTACK : constant := 16#0004#;

TODO

diff --git ./gcc/ada/init.c ./gcc/ada/init.c
@@ -2002,6 +2021,15 @@ __gnat_install_handler (void)
  trap_0_entry->inst_fourth = 0xa1480000;
#endif

{+#if (defined (i386) || defined (__i386__)) && !defined (VTHREADS)+}
{+  /*  By experiment, found that sysModel () returns the following string+}
{+      prefix for vxsim when running on Linux and Windows.  */+}
{+  model = sysModel ();+}
{+  if ((strncmp (model, "Linux", 5) == 0)+}
{+      || (strncmp (model, "Windows", 7) == 0))+}
{+    is_vxsim = 1;+}
{+#endif+}

  __gnat_handler_installed = 1;
}

diff --git ./gcc/ada/sigtramp.h ./gcc/ada/sigtramp.h
@@ -62,8 +62,14 @@ typedef struct ucontext
     system headers so call it something unique.  */
  typedef void __sigtramphandler_t (int signo, void *siginfo, void *sigcontext);

{+#if CPU == SIMNT || CPU == SIMPENTIUM || CPU == SIMLINUX+}
{+  /* Vxsim requires a specially compiled handler.  */+}
{+  void __gnat_sigtramp_vxsim  (int signo, void *siginfo, void *sigcontext,+}
{+                       __sigtramphandler_t * handler);+}
{+#else+}
  void __gnat_sigtramp  (int signo, void *siginfo, void *sigcontext,
                         __sigtramphandler_t * handler);
{+#endif+}

diff --git ./gcc/ada/gcc-interface/Makefile.in ./gcc/ada/gcc-interface/Makefile.in
@@ -923,13 +928,49 @@ ifeq ($(strip $(filter-out %86 wrs vxworks vxworks7,$(target_cpu) $(target_vendo
{+  VXSIM_CPU =+}

{+  ifeq ($(strip $(filter-out vxworks rtp rtp-smp,$(target_os) $(THREAD_KIND))),)+}
{+      VXSIM_CPU = SIMPENTIUM+}
{+  else+}
{+    ifeq ($(strip $(filter-out kernel kernel-smp rtp rtp-smp,$(THREAD_KIND))),)+}
{+      ifeq ($(strip $(filter-out linux%,$(host_os))),)+}
{+        # Linux+}
{+        VXSIM_CPU = SIMLINUX+}
{+      else+}
{+        # Windows+}
{+        VXSIM_CPU = SIMNT+}
{+      endif+}
{+    endif+}

diff --git ./gcc/ada/gcc-interface/Makefile.in ./gcc/ada/gcc-interface/Makefile.in
@@ -2413,6 +2468,14 @@ ifeq ($(filter a-except%,$(LIBGNAT_TARGET_PAIRS)),)
{+# Configuration of host tools+}

{+# Under linux, host tools need to be linked with -ldl+}

{+ifeq ($(strip $(filter-out linux%,$(host_os))),)+}
{+   TOOLS1_LIBS=-ldl+}
{+endif+}

diff --git ./gcc/ada/s-osinte-linux.ads ./gcc/ada/s-osinte-linux.ads
@@ -224,6 +224,10 @@ package System.OS_Interface is
   {+function clock_gettime+}
{+     (clock_id : clockid_t; tp : access timespec) return int;+}
{+   pragma Import (C, clock_gettime, "clock_gettime");+}

diff --git ./gcc/ada/s-taprop-linux.adb ./gcc/ada/s-taprop-linux.adb
@@ -39,7 +39,6 @@ pragma Polling (Off);
with Interfaces.C;
[-with Interfaces.C.Extensions;-]
@@ -64,7 +63,6 @@ package body System.Task_Primitives.Operations is
   use Interfaces.C;
[-   use Interfaces.C.Extensions;-]
@@ -629,30 +627,14 @@ package body System.Task_Primitives.Operations is
   function Monotonic_Clock return Duration is
      [-use Interfaces;-]

[-      procedure timeval_to_duration-]
[-        (T    : not null access timeval;-]
[-         sec  : not null access C.Extensions.long_long;-]
[-         usec : not null access C.long);-]
[-      pragma Import (C, timeval_to_duration, "__gnat_timeval_to_duration");-]

[-      Micro  : constant := 10**6;-]
[-      sec    : aliased C.Extensions.long_long;-]
[-      usec   : aliased C.long;-]
[-      TV-]{+TS+}     : aliased [-timeval;-]{+timespec;+}
      Result : int;

[-      function gettimeofday-]
[-        (Tv : access timeval;-]
[-         Tz : System.Address := System.Null_Address) return int;-]
[-      pragma Import (C, gettimeofday, "gettimeofday");-]

   begin
      Result := [-gettimeofday (TV'Access, System.Null_Address);-]{+clock_gettime+}
{+        (clock_id => OSC.CLOCK_RT_Ada, tp => TS'Unchecked_Access);+}
      pragma Assert (Result = 0);
[-timeval_to_duration (TV'Access, sec'Access, usec'Access);-]
      return [-Duration (sec) + Duration (usec) / Micro;-]{+To_Duration (TS);+}
   end Monotonic_Clock;


diff --git ./gcc/ada/adaint.c ./gcc/ada/adaint.c
@@ -3220,6 +3220,107 @@ __gnat_kill (int pid, int sig, int close ATTRIBUTE_UNUSED)
#endif
}

{+void __gnat_killprocesstree (int pid, int sig_num)+}
{+{+}
{+[...]+}
{+#elif defined (__linux__)+}
{+  DIR *dir;+}
{+  struct dirent *d;+}

{+  /*  read all processes' pid and ppid */+}

{+  dir = opendir ("/proc");+}
{+[...]+}
{+  /* kill process */+}

{+  __gnat_kill (pid, sig_num, 1);+}
{+#else+}
{+  __gnat_kill (pid, sig_num, 1);+}
{+#endif+}
{+[...]+}
{+}+}

diff --git ./gcc/ada/s-os_lib.ads ./gcc/ada/s-os_lib.ads
@@ -740,6 +744,19 @@ package System.OS_Lib is
{+   procedure Kill_Process_Tree (Pid : Process_Id; Hard_Kill : Boolean := True);+}
{+   --  Kill the process designated by Pid and all it's children processes.+}
{+   --  [...]
{+   --  Note that this routine is not atomic and is supported only on Linux+}
{+   --  and Windows. On other OS it will only kill the process identified by+}
{+   --  Pid.+}

GCC includes (TODO: some version of) the Ada Conformity Assessment Test Suite (ACATS), http://ada-auth.org/acats.html. Additional tests to be found at http://ada-auth.org/submit.html. TODO: results?

Part II

Next, Hurd-specific features can be added. Add an interface to the language/environment for being able to do RPC calls, in order to program translators natively in Ada.

Original GSoC Task Description

<antrik_> teythoon_: I don't think wrapping libtrivfs etc. for guile
  bindings is really desirable... for the lisp bindings, we agreed that
  it's better to hook in at a lower level, and build more lispish
  abstractions
<antrik> trivfs is a C framework; it probably doesn't map very well to
  other languages -- especially non-imperative ones...
<antrik> (it is arguable whether trivfs is really a good abstraction even
  for C... but that's another discussion :-) )
<antrik> ArneBab: same for Python bindings. when I suggested ignoring
  libtrivfs etc., working around the pthread problem was just a side effect
  -- the real goal has always been nicer abstraction
<anatoly> antrik: agree with you
<anatoly> antrik: about nicer abstractions
<teythoon_> antrik: I agree too, but wrapping libtrivfs is much easier
<teythoon_> otherwise, one needs to reimplement lots of stuff to get some
  basic functionality
<teythoon_> like a mig that emits your language
<braunr> i agree with antrik too
<braunr> yes, the best would be mig handling multiple languages

<antrik> teythoon_: not exactly. for dynamic languages, code generation is
  silly. just handle the marshalling on the fly. that's what the Lisp
  bindings are doing (AFAIK)
<teythoon> antrik: ok, but you'd still need to parse the rpc definitions,
  no?
<antrik> teythoon: yeah, you still need to parse the .defs -- unless we add
  reflection to RPC interfaces...
<antrik> err, I mean introspection