[Bug ada/64492] New: Disabling libada prevents building gnattools-cross

["simon at pushface dot org" <gcc-bugzilla@gcc.gnu.org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64492

            Bug ID: 64492
           Summary: Disabling libada prevents building gnattools-cross
           Product: gcc
           Version: 4.9.1
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: ada
          Assignee: unassigned at gcc dot gnu.org
          Reporter: simon at pushface dot org

Created attachment 34375
  --> https://gcc.gnu.org/bugzilla/attachment.cgi?id=34375&action=edit
Patch to add --enable-cross-gnattools

This is related to PR19959.

--disable-libada is necessary for targets (such as arm-eabi) where the RTS
isn’t distributed as part of GCC. Of course, you still need the cross gnattools
(such as arm-eabi-gnatls).

Unfortunately you can’t build the cross gnattools, because --disable-libada
adds gnattools to the list  of unconfigured directories, which means that the
directory gcc/ada/tools is never created, let alone populated.
gcc/ada/gcc-interface/Makefile.in touches stamp-tools, but that’s all.

You can’t say "make -C gcc gnattools-cross", because that’s in gnattools/. You
can’t say “make -C gcc cross-gnattools”, because the gcc/ada/tools directory
doesn’t exist.

Why does gcc/ada/gcc-interface/Makefile.in touch ../stamp-tools?
Where does the target cross-gnattools come into the picture?

I attach a patch to the top-level configure.ac which adds a new switch
--enable-cross-gnattools.

If you configure with --disable-libada, gnattools is removed from the list of
configured directories unless
* you give --enable-cross-gnattools
* and you are building a cross compiler
* and the target vendor is “none” or “unknown”.

With this patch, the normal configure/make runs through and builds the cross
gnattools without further ado. Tested on 4.9.1, --target=arm-eabi. The patch
applies to the gcc-5-20141228 snapshot with a 17-line offset.
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From: "simon at pushface dot org" <gcc-bugzilla@gcc.gnu.org>
To: gcc-bugs@gcc.gnu.org
Subject: [Bug ada/64492] Disabling libada prevents building gnattools-cross
Date: Sun, 04 Jan 2015 22:49:00 -0000
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https://gcc.gnu.org/bugzilla/show_bug.cgi?idd492

simon at pushface dot org changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Target|                            |arm-eabi
               Host|                            |x86_64-apple-darwin13
              Build|                            |x86_64-apple-darwin13

--- Comment #1 from simon at pushface dot org ---
Notes:

The patch was originated by Luke A. Guest.

I have built GCC 5 snapshot 20141228 as host and cross with this patch and used
the result to build an Ada RTS for STM32F4.