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

[Hal Finkel]

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 ;)

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"
> >>
> >>
> >> _______________________________________________
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> >> 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