[Bug regression/64812] [4.9 regression] x86 LibreOffice Build failure: undefined reference to acquire

["mstahl at redhat dot com" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=64812

Michael Stahl <mstahl at redhat dot com> changed:

           What    |Removed                     |Added
----------------------------------------------------------------------------
                 CC|                            |caolanm at redhat dot com,
                   |                            |mstahl at redhat dot com,
                   |                            |sbergman at redhat dot com

--- Comment #5 from Michael Stahl <mstahl at redhat dot com> ---
the problem is that with -Os, the inline method
 WindowListenerMultiplexer::acquire()
results in an undefined symbol, whereas with -O2
weak symbols are emitted into the object.

can reproduce this with:

gcc (GCC) 4.9.2 20141101 (Red Hat 4.9.2-1)

the command line parameters for compilation in the build system were:

g++ -m32 -fvisibility=hidden -fmessage-length=0 -fno-common
-fvisibility-inlines-hidden -fstack-protector-strong -fPIC -std=gnu++11  -ggdb2
 -fexceptions -fno-enforce-eh-specs -Os -c /tmp/fmgridif.ii -o /tmp/fmgridif.o

the minimal command line parameters to trigger the bug:

> g++ -m32 -std=gnu++11 -Os -c /tmp/fmgridif.ii -o /tmp/fmgridif.o

> nm --demangle /tmp/fmgridif.o | grep WindowListenerMultiplexer
         U non-virtual thunk to WindowListenerMultiplexer::acquire()

the minimal command line parameters to avoid the bug:

> g++ -m32 -std=gnu++11 -O2 -c /tmp/fmgridif.ii -o /tmp/fmgridif.o

> nm --demangle /tmp/fmgridif.o | grep WindowListenerMultiplexer
00000000 W WindowListenerMultiplexer::acquire()
00000020 W non-virtual thunk to WindowListenerMultiplexer::acquire()