I have same error/warning on the ECE cluster here at Wisconsin (Ubuntu
10.04 LTS which happens to be gcc 4.4 and swig 1.3.40).  I just disabled
Werror for swig.

On Wed, Mar 20, 2013 at 1:45 PM, nathan binkert <[email protected]> wrote:

> It's probably all my fault, and my guess is that the swig_env predated
> the Werror flag.  I'm fine with your proposal.
>
>   Nate
>
> On Wed, Mar 20, 2013 at 11:33 AM, Steve Reinhardt <[email protected]>
> wrote:
> > Why do we care about compiler warnings in swig-generated code?
> >
> > I just started running some tests on my Ubuntu 10.04 machine (swig
> 1.3.40,
> > gcc 4.4.3), and I ran into this on a few different _wrap.cc files:
> >
> >  [     CXX] ALPHA/python/swig/event_wrap.cc -> .fo
> > cc1plus: warnings being treated as errors
> > build/ALPHA/python/swig/event_wrap.cc: In function 'PyObject*
> > _wrap_new_Cycles(PyObject*, PyObject*)':
> > build/ALPHA/python/swig/event_wrap.cc:3380: error: 'argv[0]' may be used
> > uninitialized in this function
> > build/ALPHA/python/swig/event_wrap.cc: In function 'PyObject*
> > _wrap_simulate(PyObject*, PyObject*)':
> > build/ALPHA/python/swig/event_wrap.cc:4590: error: 'argv[0]' may be used
> > uninitialized in this function
> > scons: *** [build/ALPHA/python/swig/event_wrap.fo] Error 1
> > scons: building terminated because of errors.
> >
> > I went poking around in src/SConscript and I see that we have a mildly
> > elaborate setup to (1) use a different build environment for swig files,
> > swig_env, so we can have finer-grain control over warnings, and (2)
> figure
> > out based on the compiler type and version which warnings to suppress.  I
> > saw that the -Wno-maybe-uninitialized flag was added to swig_env only for
> > gcc versions >= 4.7, so I changed that to make it unconditional, only to
> > find that that flag isn't even valid for gcc 4.4; I had to use
> > -Wno-uninitialized instead.
> >
> > So I could solve my immediate problem by adding -Wno-uninitialized for
> gcc
> > 4.4, though I'm not sure if this is really a gcc 4.4 issue or a swig
> 1.3.40
> > issue (or maybe it's specific to that particular combination).  But in
> the
> > bigger picture I wonder: why do we really care?  We're not going to go
> fix
> > the swig output to get rid of warnings, and as long as the code compiles
> > and runs, we probably don't care about them.  Wouldn't it be simpler to
> get
> > rid of the whole swig_env thing and all the code that sets it up, and
> just
> > add 'Werror=False' when we compile swig sources?
> >
> > Steve
> > _______________________________________________
> > gem5-dev mailing list
> > [email protected]
> > http://m5sim.org/mailman/listinfo/gem5-dev
> _______________________________________________
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