[cfe-commits] r154389 - in /cfe/trunk: lib/Driver/Tools.cpp test/Driver/linux-as.c

[Hal Finkel]

On Mon, 23 Apr 2012 07:14:19 -0500
Hal Finkel <hfinkel at anl.gov> wrote:

> On Mon, 23 Apr 2012 11:14:04 +0400
> Evgeniy Stepanov <eugeni.stepanov at gmail.com> wrote:
> 
> > On Sun, Apr 22, 2012 at 5:41 AM, Hal Finkel <hfinkel at anl.gov> wrote:
> > > Evgeniy,
> > >
> > > Unfortunately, we need to be much more careful here. While gas for
> > > ARM does support -mcpu, -march and -mfpu, this is not true for
> > > other ISAs. Looking at the man page, it seems that the supported
> > > flags are:
> > >
> > > ARM: -mcpu=, -march=, -mfpu=
> > > i386: -march= (-mtune=: should we map -mcpu= to -mtune=?)
> > > MIPS: (same as i386)
> > > PowerPC: supports cpu, but as -m<cpu> (meaning
> > > -m403|-m405|-mppc64|...) SPARC: supports arch, but as -xarch=
> > >
> > > How do you think we should fix this?
> > 
> > Well, we can make the set of forwarded options dependent on the
> > target.
> 
> That makes sense.
> 
> > 
> > But what's the failing use case? I mean, why do you pass these
> > options to the compiler in the first place?
> 
> This patch broke building on PPC with a non-default cpu type. I pass
> -mcpu=, as you do, to select appropriate cpu features and itineraries.
> The default clang behavior on PPC is to pass -many to the assembler.
> As you might imagine, this enables instructions for all known cpu
> types. With this patch, the assembler also gets the -mcpu=<cpu> flag
> provided to the driver. This is incorrect, it would need to be
> translated as -m<cpu> for PPC. I think it is unfortunate that gas
> cannot accept a common set of command-line parameters across
> platforms, but that I cannot fix ;)

I should also add that it is quite possible for LLVM to have
itineraries for cpus that gas knows nothing about in particular.

 -Hal

> 
> Thanks again,
> Hal
> 
> > 
> > >
> > >  -Hal
> > >
> > > On Tue, 10 Apr 2012 09:05:41 -0000
> > > Evgeniy Stepanov <eugeni.stepanov at gmail.com> wrote:
> > >
> > >> Author: eugenis
> > >> Date: Tue Apr 10 04:05:40 2012
> > >> New Revision: 154389
> > >>
> > >> URL: http://llvm.org/viewvc/llvm-project?rev=154389&view=rev
> > >> Log:
> > >> Pass -march, -mcpu, -mfpu to linuxtools assembler.
> > >>
> > >> Added:
> > >>     cfe/trunk/test/Driver/linux-as.c
> > >> Modified:
> > >>     cfe/trunk/lib/Driver/Tools.cpp
> > >>
> > >> Modified: cfe/trunk/lib/Driver/Tools.cpp
> > >> URL:
> > >> http://llvm.org/viewvc/llvm-project/cfe/trunk/lib/Driver/Tools.cpp?rev=154389&r1=154388&r2=154389&view=diff
> > >> ==============================================================================
> > >> --- cfe/trunk/lib/Driver/Tools.cpp (original) +++
> > >> cfe/trunk/lib/Driver/Tools.cpp Tue Apr 10 04:05:40 2012 @@
> > >> -5089,6 +5089,10 @@ CmdArgs.push_back("-EL");
> > >>    }
> > >>
> > >> +  Args.AddLastArg(CmdArgs, options::OPT_march_EQ);
> > >> +  Args.AddLastArg(CmdArgs, options::OPT_mcpu_EQ);
> > >> +  Args.AddLastArg(CmdArgs, options::OPT_mfpu_EQ);
> > >> +
> > >>    Args.AddAllArgValues(CmdArgs, options::OPT_Wa_COMMA,
> > >>                         options::OPT_Xassembler);
> > >>
> > >>
> > >> Added: cfe/trunk/test/Driver/linux-as.c
> > >> URL:
> > >> http://llvm.org/viewvc/llvm-project/cfe/trunk/test/Driver/linux-as.c?rev=154389&view=auto
> > >> ==============================================================================
> > >> --- cfe/trunk/test/Driver/linux-as.c (added) +++
> > >> cfe/trunk/test/Driver/linux-as.c Tue Apr 10 04:05:40 2012 @@ -0,0
> > >> +1,31 @@ +// Check passing options to the assembler for ARM
> > >> targets. +//
> > >> +// RUN: %clang -target arm-linux -### \
> > >> +// RUN:   -no-integrated-as -c %s 2>&1 \
> > >> +// RUN:   | FileCheck -check-prefix=ARM %s
> > >> +// CHECK-ARM: as{{(.exe)?}}"
> > >> +//
> > >> +// RUN: %clang -target arm-linux -mcpu=cortex-a8 -### \
> > >> +// RUN:   -no-integrated-as -c %s 2>&1 \
> > >> +// RUN:   | FileCheck -check-prefix=ARM-MCPU %s
> > >> +// CHECK-ARM-MCPU: as{{(.exe)?}}" "-mcpu=cortex-a8"
> > >> +//
> > >> +// RUN: %clang -target arm-linux -mfpu=neon -### \
> > >> +// RUN:   -no-integrated-as -c %s 2>&1 \
> > >> +// RUN:   | FileCheck -check-prefix=ARM-MFPU %s
> > >> +// CHECK-ARM-MFPU: as{{(.exe)?}}" "-mfpu=neon"
> > >> +//
> > >> +// RUN: %clang -target arm-linux -march=armv7-a -### \
> > >> +// RUN:   -no-integrated-as -c %s 2>&1 \
> > >> +// RUN:   | FileCheck -check-prefix=ARM-MARCH %s
> > >> +// CHECK-ARM-MARCH: as{{(.exe)?}}" "-march=armv7-a"
> > >> +//
> > >> +// RUN: %clang -target arm-linux -mcpu=cortex-a8 -mfpu=neon
> > >> -march=armv7-a -### \ +// RUN:   -no-integrated-as -c %s 2>&1 \
> > >> +// RUN:   | FileCheck -check-prefix=ARM-ALL %s
> > >> +// CHECK-ARM-ALL: as{{(.exe)?}}" "-march=armv7-a"
> > >> "-mcpu=cortex-a8" "-mfpu=neon" +//
> > >> +// RUN: %clang -target armv7-linux -mcpu=cortex-a8 -### \
> > >> +// RUN:   -no-integrated-as -c %s 2>&1 \
> > >> +// RUN:   | FileCheck -check-prefix=ARM-TARGET %s
> > >> +// CHECK-ARM-TARGET: as{{(.exe)?}}" "-mfpu=neon"
> > >> "-mcpu=cortex-a8"
> > >>
> > >>
> > >> _______________________________________________
> > >> cfe-commits mailing list
> > >> cfe-commits at cs.uiuc.edu
> > >> http://lists.cs.uiuc.edu/mailman/listinfo/cfe-commits
> > >
> > >
> > >
> > > --
> > > Hal Finkel
> > > Postdoctoral Appointee
> > > Leadership Computing Facility
> > > Argonne National Laboratory
> 
> 
> 



-- 
Hal Finkel
Postdoctoral Appointee
Leadership Computing Facility
Argonne National Laboratory