[PATCH][Solaris] Default to -fno-cxa-finalize

[Xan López via cfe-commits]

On Sat, Sep 05, 2015 at 12:25:28PM -0700, Saleem Abdulrasool wrote:
> > Ping?
> >
> 
> Does this break with older Solaris releases?  How far back did this change
> in Solaris?  The change itself should really be accompanied with a test.

Hi,

turns out I'm not really sure cxa_finalize.o was ever available on
Solaris. The initial code for Solaris was pushed in 2012, but it was
hardcoded to work on a pretty specific Solaris/x86 environment. One
commit from that time is r151648, which claims -fno-cxa-atexit
produces broken code and says they'll ship their own
cxa_finalize.o. So it seems it was not available back then
either. I've also seen commits in OpenSolaris from 2013 creating dummy
cxa_finalize.o files so that clang will pass the bare minimum tests.

Now that I'm slowly pushing changes to make clang/Solaris work again
(it was totally broken) I've found this issue again. My patch allows
me to compile clang with clang itself, and other simple C++ programs
compile and work. So if there was a bug here it was either fixed or I
have not found it yet. I'd say that we should probably fix whatever
issue there is with -fno-cxa-atexit when it shows up instead of
working around it, or maybe *actually* bundle an implementation for
Solaris with clang itself? But suggestions are welcome.

Also, what kind of test would you have in mind for this?

Xan

> 
> 
> > > From 014ddb164689a3452b76f85079f213d607d07840 Mon Sep 17 00:00:00 2001
> > > From: =?UTF-8?q?Xan=20L=C3=B3pez?= <xan at igalia.com>
> > > Date: Fri, 14 Aug 2015 11:36:56 +0200
> > > Subject: [PATCH 2/4] [Solaris] Default to -fno-cxa-finalize
> > >
> > > There is no __cxa_finalize symbol available on recent Solaris OS
> > > versions, so we need this flag to make non trivial C++ programs run.
> > >
> > > Also stop looking for cxa_finalize.o, since it won't be there.
> > > ---
> > >  lib/Driver/Tools.cpp | 9 +++------
> > >  1 file changed, 3 insertions(+), 6 deletions(-)
> > >
> > > diff --git a/lib/Driver/Tools.cpp b/lib/Driver/Tools.cpp
> > > index b204961..cf01d7b 100644
> > > --- a/lib/Driver/Tools.cpp
> > > +++ b/lib/Driver/Tools.cpp
> > > @@ -4506,8 +4506,9 @@ void Clang::ConstructJob(Compilation &C, const
> > JobAction &JA,
> > >    if (!Args.hasFlag(options::OPT_fuse_cxa_atexit,
> > >                      options::OPT_fno_use_cxa_atexit,
> > >                      !IsWindowsCygnus && !IsWindowsGNU &&
> > > -                        getToolChain().getArch() !=
> > llvm::Triple::hexagon &&
> > > -                        getToolChain().getArch() !=
> > llvm::Triple::xcore) ||
> > > +                    getToolChain().getTriple().getOS() !=
> > llvm::Triple::Solaris &&
> > > +                    getToolChain().getArch() != llvm::Triple::hexagon &&
> > > +                    getToolChain().getArch() != llvm::Triple::xcore) ||
> > >        KernelOrKext)
> > >      CmdArgs.push_back("-fno-use-cxa-atexit");
> > >
> > > @@ -6882,10 +6883,6 @@ void solaris::Linker::ConstructJob(Compilation
> > &C, const JobAction &JA,
> > >          Args.MakeArgString(getToolChain().GetFilePath("values-Xa.o")));
> > >      CmdArgs.push_back(
> > >          Args.MakeArgString(getToolChain().GetFilePath("crtbegin.o")));
> > > -
> > > -    if (getToolChain().getDriver().CCCIsCXX())
> > > -      CmdArgs.push_back(
> > > -
> > Args.MakeArgString(getToolChain().GetFilePath("cxa_finalize.o")));
> > >    }
> > >
> > >    const ToolChain::path_list &Paths = getToolChain().getFilePaths();
> > > --
> > > 2.4.3
> > >
> >
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> 
> 
> 
> -- 
> Saleem Abdulrasool
> compnerd (at) compnerd (dot) org