* [power-iee128] How to specify linker flags [not found] ` <YYA2FMfDR0yehJLA@toto.the-meissners.org> @ 2022-01-02 22:58 ` Thomas Koenig 2022-01-03 10:19 ` Thomas Koenig 2022-01-05 21:20 ` Michael Meissner 0 siblings, 2 replies; 5+ messages in thread From: Thomas Koenig @ 2022-01-02 22:58 UTC (permalink / raw) To: Michael Meissner, Bill Schmidt, fortran, Jakub Jelinek, Segher Boessenkool, Peter Bergner, David Edelsohn, gcc mailing list Hi Michael, > If you are building libraries that contain modules with multiple long double > types, you must use the '-mno-gnu-attribute'. We also use the '-Wno-psabi' > option, which silences the warning that you are switching long double types (if > glibc is not 2.34 or newer). We may need to tweak -Wno-psabi for use with > Fortran. I am now at the point where the object files are also compiled correctly for the gfortran specifics: 0000000000000000 <_gfortran_specific__abs_r17>: 0: 09 00 43 f4 lxv vs34,0(r3) 4: 48 16 40 fc xsabsqp v2,v2 8: 20 00 80 4e blr However, the linker complains, as you said it would, about the different formats: /opt/at15.0/bin/ld: .libs/maxloc0_4_r16.o uses IBM long double, .libs/_abs_r17.o uses IEEE long double /opt/at15.0/bin/ld: failed to merge target specific data of file .libs/_abs_r17.o I know next to nothing about libtool, so I do not know how to add the flags so the linker can find them. Any pointers? (I have not yet committed the changes because I do not want to commit something that does not compile. If anybody wants to take a look, it's on the ieee128 virtual machine under /home/tkoenig/ieee ). Regards Thomas ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [power-iee128] How to specify linker flags 2022-01-02 22:58 ` [power-iee128] How to specify linker flags Thomas Koenig @ 2022-01-03 10:19 ` Thomas Koenig 2022-01-03 10:33 ` Jakub Jelinek 2022-01-03 10:34 ` Segher Boessenkool 2022-01-05 21:20 ` Michael Meissner 1 sibling, 2 replies; 5+ messages in thread From: Thomas Koenig @ 2022-01-03 10:19 UTC (permalink / raw) To: Michael Meissner, Bill Schmidt, fortran, Jakub Jelinek, Segher Boessenkool, Peter Bergner, David Edelsohn, gcc mailing list On 02.01.22 23:58, Thomas Koenig wrote: > Hi Michael, > >> If you are building libraries that contain modules with multiple long >> double >> types, you must use the '-mno-gnu-attribute'. We also use the >> '-Wno-psabi' >> option, which silences the warning that you are switching long double >> types (if >> glibc is not 2.34 or newer). We may need to tweak -Wno-psabi for use >> with >> Fortran. > > I am now at the point where the object files are also compiled correctly > for the gfortran specifics: > > 0000000000000000 <_gfortran_specific__abs_r17>: > 0: 09 00 43 f4 lxv vs34,0(r3) > 4: 48 16 40 fc xsabsqp v2,v2 > 8: 20 00 80 4e blr > > However, the linker complains, as you said it would, about the different > formats: > > /opt/at15.0/bin/ld: .libs/maxloc0_4_r16.o uses IBM long double, > .libs/_abs_r17.o uses IEEE long double > /opt/at15.0/bin/ld: failed to merge target specific data of file > .libs/_abs_r17.o > > I know next to nothing about libtool, so I do not know how to > add the flags so the linker can find them. > > Any pointers? One additional point. The linker does not understand -mno-gnu-attribute: $ /opt/at15.0/bin/ld -mno-gnu-attribute /opt/at15.0/bin/ld: unrecognised emulation mode: no-gnu-attribute Supported emulations: elf64lppc elf32lppc elf32lppclinux elf32lppcsim elf64ppc elf32ppc elf32ppclinux elf32ppcsim So, waiting for info to proceed. Best regards Thomas ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [power-iee128] How to specify linker flags 2022-01-03 10:19 ` Thomas Koenig @ 2022-01-03 10:33 ` Jakub Jelinek 2022-01-03 10:34 ` Segher Boessenkool 1 sibling, 0 replies; 5+ messages in thread From: Jakub Jelinek @ 2022-01-03 10:33 UTC (permalink / raw) To: Thomas Koenig Cc: Michael Meissner, Bill Schmidt, fortran, Segher Boessenkool, Peter Bergner, David Edelsohn, gcc mailing list On Mon, Jan 03, 2022 at 11:19:21AM +0100, Thomas Koenig wrote: > > > If you are building libraries that contain modules with multiple > > > long double > > > types, you must use the '-mno-gnu-attribute'. We also use the > > > '-Wno-psabi' > > > option, which silences the warning that you are switching long > > > double types (if > > > glibc is not 2.34 or newer). We may need to tweak -Wno-psabi for > > > use with > > > Fortran. > > > > I am now at the point where the object files are also compiled correctly > > for the gfortran specifics: > > > > 0000000000000000 <_gfortran_specific__abs_r17>: > > 0: 09 00 43 f4 lxv vs34,0(r3) > > 4: 48 16 40 fc xsabsqp v2,v2 > > 8: 20 00 80 4e blr > > > > However, the linker complains, as you said it would, about the different > > formats: > > > > /opt/at15.0/bin/ld: .libs/maxloc0_4_r16.o uses IBM long double, > > .libs/_abs_r17.o uses IEEE long double > > /opt/at15.0/bin/ld: failed to merge target specific data of file > > .libs/_abs_r17.o > > > > I know next to nothing about libtool, so I do not know how to > > add the flags so the linker can find them. > > > > Any pointers? > > One additional point. The linker does not understand > -mno-gnu-attribute: > > $ /opt/at15.0/bin/ld -mno-gnu-attribute > /opt/at15.0/bin/ld: unrecognised emulation mode: no-gnu-attribute > Supported emulations: elf64lppc elf32lppc elf32lppclinux elf32lppcsim > elf64ppc elf32ppc elf32ppclinux elf32ppcsim > > So, waiting for info to proceed. -mno-gnu-attribute isn't a linker flag, but a compiler flag. And e.g. libstdc++ configure uses it while compiling itself on powerpc*linux: LONG_DOUBLE_COMPAT_FLAGS="$LONG_DOUBLE_COMPAT_FLAGS -mno-gnu-attribute" # Check for IEEE128 support in libm: AC_CHECK_LIB(m, __frexpieee128, [ac_ldbl_ieee128_in_libc=yes], [ac_ldbl_ieee128_in_libc=no]) if test $ac_ldbl_ieee128_in_libc = yes; then # Determine which long double format is the compiler's default: AC_TRY_COMPILE(, [ #ifndef __LONG_DOUBLE_IEEE128__ #error compiler defaults to ibm128 #endif ], [ac_ldbl_ieee128_default=yes], [ac_ldbl_ieee128_default=no]) # Library objects should use default long double format. if test "$ac_ldbl_ieee128_default" = yes; then LONG_DOUBLE_128_FLAGS="-mno-gnu-attribute" # Except for the ones that explicitly use these flags: LONG_DOUBLE_ALT128_COMPAT_FLAGS="-mabi=ibmlongdouble -mno-gnu-attribute -Wno-psabi" else LONG_DOUBLE_128_FLAGS="-mno-gnu-attribute" LONG_DOUBLE_ALT128_COMPAT_FLAGS="-mabi=ieeelongdouble -mno-gnu-attribute -Wno-psabi" fi AC_DEFINE([_GLIBCXX_LONG_DOUBLE_ALT128_COMPAT],1, [Define if compatibility should be provided for alternative 128-bit long double formats.]) port_specific_symbol_files="$port_specific_symbol_files \$(top_srcdir)/config/os/gnu-linux/ldbl-ieee128-extra.ver" ac_ldbl_alt128_compat=yes else ac_ldbl_alt128_compat=no fi ;; The idea behind this is that libstdc++ is written such that it can handle both IBM extended and IEEE quad long double, so its object files are compatible with both. So I think we want: 2022-01-03 Jakub Jelinek <jakub@redhat.com> * configure.ac (Use -mno-gnu-attribute together with -mabi=ibmlongdouble or -mabi=ieeelongdouble. --- libgfortran/configure.ac 2021-12-31 11:08:19.032835533 +0000 +++ libgfortran/configure.ac 2022-01-03 10:32:16.927834682 +0000 @@ -163,9 +163,9 @@ if test "x$GCC" = "xyes"; then #error long double is double #endif]], [[(void) 0;]])], - [AM_FCFLAGS="$AM_FCFLAGS -mabi=ibmlongdouble"; - AM_CFLAGS="$AM_CFLAGS -mabi=ibmlongdouble"; - CFLAGS="$CFLAGS -mabi=ibmlongdouble"; + [AM_FCFLAGS="$AM_FCFLAGS -mabi=ibmlongdouble -mno-gnu-attribute"; + AM_CFLAGS="$AM_CFLAGS -mabi=ibmlongdouble -mno-gnu-attribute"; + CFLAGS="$CFLAGS -mabi=ibmlongdouble -mno-gnu-attribute"; have_real_17=yes]) ;; *) Jakub ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [power-iee128] How to specify linker flags 2022-01-03 10:19 ` Thomas Koenig 2022-01-03 10:33 ` Jakub Jelinek @ 2022-01-03 10:34 ` Segher Boessenkool 1 sibling, 0 replies; 5+ messages in thread From: Segher Boessenkool @ 2022-01-03 10:34 UTC (permalink / raw) To: Thomas Koenig Cc: Michael Meissner, Bill Schmidt, fortran, Jakub Jelinek, Peter Bergner, David Edelsohn, gcc mailing list Hi! On Mon, Jan 03, 2022 at 11:19:21AM +0100, Thomas Koenig wrote: > One additional point. The linker does not understand > -mno-gnu-attribute: That is a GCC option, not an ld one. If you use it to compile some file there will be no .gnu.attributes section generated for that translation unit. Segher ^ permalink raw reply [flat|nested] 5+ messages in thread
* Re: [power-iee128] How to specify linker flags 2022-01-02 22:58 ` [power-iee128] How to specify linker flags Thomas Koenig 2022-01-03 10:19 ` Thomas Koenig @ 2022-01-05 21:20 ` Michael Meissner 1 sibling, 0 replies; 5+ messages in thread From: Michael Meissner @ 2022-01-05 21:20 UTC (permalink / raw) To: Thomas Koenig Cc: Michael Meissner, Bill Schmidt, fortran, Jakub Jelinek, Segher Boessenkool, Peter Bergner, David Edelsohn, gcc mailing list On Sun, Jan 02, 2022 at 11:58:29PM +0100, Thomas Koenig wrote: > Hi Michael, > > > If you are building libraries that contain modules with multiple long double > > types, you must use the '-mno-gnu-attribute'. We also use the '-Wno-psabi' > > option, which silences the warning that you are switching long double types (if > > glibc is not 2.34 or newer). We may need to tweak -Wno-psabi for use with > > Fortran. > > I am now at the point where the object files are also compiled correctly > for the gfortran specifics: > > 0000000000000000 <_gfortran_specific__abs_r17>: > 0: 09 00 43 f4 lxv vs34,0(r3) > 4: 48 16 40 fc xsabsqp v2,v2 > 8: 20 00 80 4e blr > > However, the linker complains, as you said it would, about the different > formats: > > /opt/at15.0/bin/ld: .libs/maxloc0_4_r16.o uses IBM long double, > .libs/_abs_r17.o uses IEEE long double > /opt/at15.0/bin/ld: failed to merge target specific data of file > .libs/_abs_r17.o > > I know next to nothing about libtool, so I do not know how to > add the flags so the linker can find them. > > Any pointers? > > (I have not yet committed the changes because I do not want to > commit something that does not compile. If anybody wants to > take a look, it's on the ieee128 virtual machine under > /home/tkoenig/ieee ). I'm just getting back into things after being off-line for the winter holidays. As others have said, you need to use the GCC option -mno-gnu-attributes on any module that handles one of the long double types if you are building libraries that can handle both. Note, for C/C++ languages, you should add -Wno-psabi to the options as well as -mabi={ieee,ibm}longdouble. This suppresses the warning that says you are changing the long double type. If you have configred GCC against GLIBC 2.32 or newer, then you don't need the -Wno-psabi option. Unfortunately, you can't use -Wno-psabi on languages like Fortran. -- Michael Meissner, IBM PO Box 98, Ayer, Massachusetts, USA, 01432 email: meissner@linux.ibm.com ^ permalink raw reply [flat|nested] 5+ messages in thread
end of thread, other threads:[~2022-01-05 21:20 UTC | newest] Thread overview: 5+ messages (download: mbox.gz / follow: Atom feed) -- links below jump to the message on this page -- [not found] <63b5434e-f8fa-97b3-d357-e25094579b16@netcologne.de> [not found] ` <bdc02706-a5ae-1389-906d-50c502b87d5f@linux.ibm.com> [not found] ` <YYA2FMfDR0yehJLA@toto.the-meissners.org> 2022-01-02 22:58 ` [power-iee128] How to specify linker flags Thomas Koenig 2022-01-03 10:19 ` Thomas Koenig 2022-01-03 10:33 ` Jakub Jelinek 2022-01-03 10:34 ` Segher Boessenkool 2022-01-05 21:20 ` Michael Meissner
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