[Bug go/54918] New: libgo.so.0 is not runtime compatible between gcc-4.6.2 and gcc-4.7.x

[Bug go/54918] New: libgo.so.0 is not runtime compatible between gcc-4.6.2 and gcc-4.7.x

[gafton at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54918

             Bug #: 54918
           Summary: libgo.so.0 is not runtime compatible between gcc-4.6.2
                    and gcc-4.7.x
    Classification: Unclassified
           Product: gcc
           Version: 4.7.2
            Status: UNCONFIRMED
          Severity: major
          Priority: P3
         Component: go
        AssignedTo: ian@airs.com
        ReportedBy: gafton@gmail.com


gcc-4.6.2 shipped a libgo.so.0.0.0 runtime library.

Compiling a simple hello world binary against that libgo worked okay:

bash$ cat hello.go
package main
import "fmt"
func main() {
  fmt.Println("Hello, world")
}
bash$ gccgo -o hello hello.go
bash$ ./hello
Hello, world

When  the gcc runtime is updated on the system to gcc-4.7.2, the previouslt
compiled binary against the gcc-4.6.2 libgo.so.0 no longer works:

bash$ ./hello
./hello: symbol lookup error: ./hello: undefined symbol: libgo_os.os.Envs

Clearly the two libgo.so.0.0.0 libraries are not compatible between gcc-4.6.x
and gcc-4.7.x - as such, the soname versioning should reflect that.

[Bug go/54918] libgo.so.0 is not runtime compatible between gcc-4.6.2 and gcc-4.7.x

[rguenth at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54918

Richard Biener <rguenth at gcc dot gnu.org> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
           Keywords|                            |ABI
             Status|UNCONFIRMED                 |NEW
   Last reconfirmed|                            |2012-10-15
     Ever Confirmed|0                           |1

--- Comment #1 from Richard Biener <rguenth at gcc dot gnu.org> 2012-10-15 09:51:24 UTC ---
incompatible as in missing symbols or in incompatible behavior between
different
symbols?

Ian, you either need to bump the SONAME every release or use proper symbol
versioning.

[Bug go/54918] libgo.so.0 is not runtime compatible between gcc-4.6.2 and gcc-4.7.x

[gafton at gmail dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54918

--- Comment #2 from Cristian Gafton <gafton at gmail dot com> 2012-10-15 17:53:46 UTC ---
(In reply to comment #1)
> incompatible as in missing symbols or in incompatible behavior between
> different
> symbols?

I have only run across missing symbols, but it looks like none of the changes
in the libgo library have been dressed with any sort of symbol versioning, so
there could also be some incompatible behaviour changes. I have not studied the
libgo source enough to make that determination though;  the missing symbols
make it hard to test older binaries to check for behavioral changes.

[Bug go/54918] libgo.so.0 is not runtime compatible between gcc-4.6.2 and gcc-4.7.x

[ian at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54918

--- Comment #3 from ian at gcc dot gnu.org <ian at gcc dot gnu.org> 2012-10-23 05:01:31 UTC ---
Author: ian
Date: Tue Oct 23 05:01:24 2012
New Revision: 192706

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=192706
Log:
    PR go/54918
libgo: Set library version number.

Modified:
    trunk/libgo/Makefile.am
    trunk/libgo/Makefile.in
    trunk/libgo/configure
    trunk/libgo/configure.ac

[Bug go/54918] libgo.so.0 is not runtime compatible between gcc-4.6.2 and gcc-4.7.x

[ian at airs dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54918

Ian Lance Taylor <ian at airs dot com> changed:

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

--- Comment #4 from Ian Lance Taylor <ian at airs dot com> 2012-10-23 05:02:23 UTC ---
Thanks for pointing this out.  The different versions of libgo are not
compatible.  I haven't even thought about maintaining that.  I committed
patches to use different version numbers going forward.

[Bug go/54918] libgo.so.0 is not runtime compatible between gcc-4.6.2 and gcc-4.7.x

[ian at gcc dot gnu.org]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54918

--- Comment #5 from ian at gcc dot gnu.org <ian at gcc dot gnu.org> 2012-10-23 18:12:55 UTC ---
Author: ian
Date: Tue Oct 23 18:12:46 2012
New Revision: 192738

URL: http://gcc.gnu.org/viewcvs?root=gcc&view=rev&rev=192738
Log:
    PR go/54918
Revert previous patch: do not change libgo SONAME on branch.

Modified:
    branches/gcc-4_7-branch/libgo/Makefile.am
    branches/gcc-4_7-branch/libgo/Makefile.in
    branches/gcc-4_7-branch/libgo/configure
    branches/gcc-4_7-branch/libgo/configure.ac

[Bug go/54918] libgo.so.0 is not runtime compatible between gcc-4.6.2 and gcc-4.7.x

[ian at airs dot com]

http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54918

--- Comment #6 from Ian Lance Taylor <ian at airs dot com> 2012-10-23 18:14:04 UTC ---
Jakub Jelinek asked that I not change the libgo SONAME now that GCC 4.7 has
been released.  So libgo in GCC 4.6 and 4.7 use the same SONAME but are
incompatible, and that is just the way it is.  Sorry.