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[[!meta copyright="Copyright © 2011, 2012, 2013 Free Software Foundation,
Inc."]]

[[!meta license="""[[!toggle id="license" text="GFDL 1.2+"]][[!toggleable
id="license" text="Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License, Version 1.2 or
any later version published by the Free Software Foundation; with no Invariant
Sections, no Front-Cover Texts, and no Back-Cover Texts.  A copy of the license
is included in the section entitled [[GNU Free Documentation
License|/fdl]]."]]"""]]

[[!meta title="Enable Ada programming (GCC: GNAT)"]]

[[!tag open_issue_gcc]]

Make the Ada programming language available on GNU/Hurd in its [[service_solahart_jakarta_selatan__082122541663/Gcc]] GNAT
implementation, and enable Hurd-specific features.

There is a [[!FF_project 259]][[!tag bounty]] on this task.

---


# Part I

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


## Original [[community/GSoC]] Task Description

[[!inline pages=community/gsoc/project_ideas/gnat feeds=no]]


## 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.


## Svante's patch

A basic port has been done by Svante, [[!debbug 668425]], [[!debbug 681998]],
[[!message-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|tschwinge]] have not yet found the time to follow up on, [[!message-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.


## `getcontext`/`makecontext`/`setcontext`/`swapcontext` usage analysis

In context of [[glibc/t/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;


---


# 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
[[hurd/translator]]s natively in Ada.


## Original [[community/GSoC]] Task Description

[[!inline pages=community/gsoc/project_ideas/language_bindings feeds=no]]