[Bug jit/64780] New: toplevel configure should reject jit as a language if --enable-host-shared is not supplied

[Bug jit/64780] New: toplevel configure should reject jit as a language if --enable-host-shared is not supplied

[pinskia at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64780

            Bug ID: 64780
           Summary: toplevel configure should reject jit as a language if
                    --enable-host-shared is not supplied
           Product: gcc
           Version: 5.0
            Status: UNCONFIRMED
          Keywords: build
          Severity: normal
          Priority: P3
         Component: jit
          Assignee: dmalcolm at gcc dot gnu.org
          Reporter: pinskia at gcc dot gnu.org

When I was going to test the JIT front-end but since I did not read the
documentation, I did not know I need to configure with --enable-host-shared.

I think it would be a good idea to either default to --enable-host-shared when
jit is a language or have the toplevel configure reject jit as language if
--enable-host-shared is not supplied.

[Bug jit/64780] toplevel configure should reject jit as a language if --enable-host-shared is not supplied

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64780

--- Comment #1 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
We seem to have two choices here:

(A) default to --enable-host-shared when jit is an enabled language
(B) have the toplevel configure reject jit as language if --enable-host-shared
is not supplied.

FWIW apparently Darwin defaults to position-independent code, so it's not
explicitly needed there.

That said, I think I prefer (B), since there is a performance cost: my thinking
here is that there are people who perform benchmarking of GCC (and publish
their results on prominent websites).  If they turn on the jit and use the same
configuration to do their benchmarking of the rest of GCC, they'll see GCC 5 be
apparently slower than earlier releases.  You're a gcc expert, and you ran into
this issue, so it's clearly unreasonable to expect a 3rd-party reviewer to
notice this detail on their own.

So I'm thinking of implementing (B), and putting in a note in the error message
recommending that people configure and build GCC twice to avoid the performance
hit, so that it can be self-documenting.

[Bug jit/64780] toplevel configure should reject jit as a language if --enable-host-shared is not supplied

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64780

David Malcolm <dmalcolm at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|UNCONFIRMED                 |ASSIGNED
   Last reconfirmed|                            |2015-01-27
     Ever confirmed|0                           |1

--- Comment #2 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Patch posted as:
  https://gcc.gnu.org/ml/gcc-patches/2015-01/msg02428.html

[Bug jit/64780] toplevel configure should reject jit as a language if --enable-host-shared is not supplied

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64780

--- Comment #3 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
Author: dmalcolm
Date: Thu Jan 29 16:25:14 2015
New Revision: 220253

URL: https://gcc.gnu.org/viewcvs?rev=220253&root=gcc&view=rev
Log:
PR jit/64780: configure: --enable-host-shared and the jit

ChangeLog:
    PR jit/64780
    * configure.ac: Require the user to explicitly specify
    --enable-host-shared if the jit is enabled.
    * configure: Regenerate.


Modified:
    trunk/ChangeLog
    trunk/configure
    trunk/configure.ac

[Bug jit/64780] toplevel configure should reject jit as a language if --enable-host-shared is not supplied

[dmalcolm at gcc dot gnu.org]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64780

David Malcolm <dmalcolm at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
             Status|ASSIGNED                    |RESOLVED
         Resolution|---                         |FIXED

--- Comment #4 from David Malcolm <dmalcolm at gcc dot gnu.org> ---
I've also added some docs on how to package the jit:
  https://gcc.gnu.org/ml/gcc-patches/2015-03/msg00759.html

Closing this bug out