include/linux/compiler-gcc.h | 9 +++++++++ include/linux/compiler_types.h | 2 +- 2 files changed, 10 insertions(+), 1 deletion(-)
All my gcc-11 compilers (Ubuntu 11.4.0-1ubuntu1~22.04) claim to support
the __retain__ attribute, but only riscv64-linux-gnu-gcc-11 and
x86_64-linux-gnu-gcc-11 (not x86_64-linux-gnux32-gcc-11!) actually do.
The arm-linux-gnueabi-gcc-11.5.0 compiler from kernel.org crosstool
fails in the same way:
error: ‘retain’ attribute ignored [-Werror=attributes]
All my gcc-12 compilers seem to support the attribute.
Play it safe, and disable __retain unconditionally on gcc-11.
Fixes: 0a5d3258d7c97295 ("compiler_types.h: Define __retain for __attribute__((__retain__))")
Signed-off-by: Geert Uytterhoeven <geert+renesas@glider.be>
Reviewed-by: Tony Ambardar <tony.ambardar@gmail.com>
---
Tested with the following gcc-11 compilers:
1. All compilers available on Ubuntu 22.04LTS:
aarch64-linux-gnu-gcc-11
alpha-linux-gnu-gcc-11
arm-linux-gnueabi-gcc-11
arm-linux-gnueabihf-gcc-11
hppa64-linux-gnu-gcc-11
hppa-linux-gnu-gcc-11
i686-linux-gnu-gcc-11
m68k-linux-gnu-gcc-11
powerpc64le-linux-gnu-gcc-11
powerpc64-linux-gnu-gcc-11
powerpc-linux-gnu-gcc-11
riscv64-linux-gnu-gcc-11
s390x-linux-gnu-gcc-11
sh4-linux-gnu-gcc-11
sparc64-linux-gnu-gcc-11
x86_64-linux-gnu-gcc-11
x86_64-linux-gnux32-gcc-11
2. A few from kernel.org crosstool:
ia64-linux-gcc-11.1.0
sh2eb-linux-muslfdpic-gcc-11.2.0
arm-linux-gnueabi-gcc-11.5.0
3. A compiler from the J-Core folks:
sh2eb-linux-muslfdpic-gcc-11.2.0
v2:
- Update comment in <linux/compiler_types.h>,
- Add Reviewed-by.
---
include/linux/compiler-gcc.h | 9 +++++++++
include/linux/compiler_types.h | 2 +-
2 files changed, 10 insertions(+), 1 deletion(-)
diff --git a/include/linux/compiler-gcc.h b/include/linux/compiler-gcc.h
index f805adaa316e9a21..bedeb76b63a34745 100644
--- a/include/linux/compiler-gcc.h
+++ b/include/linux/compiler-gcc.h
@@ -145,3 +145,12 @@
#if GCC_VERSION < 90100
#undef __alloc_size__
#endif
+
+/*
+ * Most 11.x compilers claim to support it, but only riscv64-linux-gnu-gcc and
+ * x86_64-linux-gnu-gcc actually do.
+ */
+#if GCC_VERSION < 120000
+#undef __retain
+#define __retain
+#endif
diff --git a/include/linux/compiler_types.h b/include/linux/compiler_types.h
index 1a957ea2f4fe78ed..76ddf04a7e66f890 100644
--- a/include/linux/compiler_types.h
+++ b/include/linux/compiler_types.h
@@ -153,7 +153,7 @@ static inline void __chk_io_ptr(const volatile void __iomem *ptr) { }
* being optimized out, but operates at the compiler/IR-level and may still
* allow unintended removal of objects during linking.
*
- * Optional: only supported since gcc >= 11, clang >= 13
+ * Optional: only supported since gcc >= 11 (partial), clang >= 13
*
* gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-retain-function-attribute
* clang: https://clang.llvm.org/docs/AttributeReference.html#retain
--
2.34.1
On Okt 02 2024, Geert Uytterhoeven wrote: > + * Optional: only supported since gcc >= 11 (partial), clang >= 13 This is misleading. gcc fully supports it since 11 as long as binutils supports SHF_GNU_RETAIN. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."
Hi Andreas,
On Wed, Oct 2, 2024 at 7:00 PM Andreas Schwab <schwab@linux-m68k.org> wrote:
> On Okt 02 2024, Geert Uytterhoeven wrote:
>
> > + * Optional: only supported since gcc >= 11 (partial), clang >= 13
>
> This is misleading. gcc fully supports it since 11 as long as binutils
> supports SHF_GNU_RETAIN.
It fails for me with arm-linux-gnueabihf-gcc-11 (gcc version 11.4.0
(Ubuntu 11.4.0-1ubuntu1~22.04)).
$ arm-linux-gnueabihf-as -v
GNU assembler version 2.38 (arm-linux-gnueabihf) using BFD version
(GNU Binutils for Ubuntu) 2.38
In response to v1, you replied:
| That ultimately depends on binutils support for SHF_GNU_RETAIN (2.36+).
So binutils 2.38-4ubuntu2.6 is sufficiently new, but it doesn't work?
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
On Okt 03 2024, Geert Uytterhoeven wrote: > | That ultimately depends on binutils support for SHF_GNU_RETAIN (2.36+). > > So binutils 2.38-4ubuntu2.6 is sufficiently new, but it doesn't work? It ultimately depends on the binutils version the compiler was built against. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."
Hi Andreas,
On Thu, Oct 3, 2024 at 10:42 AM Andreas Schwab <schwab@linux-m68k.org> wrote:
> On Okt 03 2024, Geert Uytterhoeven wrote:
> > | That ultimately depends on binutils support for SHF_GNU_RETAIN (2.36+).
> >
> > So binutils 2.38-4ubuntu2.6 is sufficiently new, but it doesn't work?
>
> It ultimately depends on the binutils version the compiler was built
> against.
Is there an easy way to check that version?
debian/rules for the gcc-11-cross-11ubuntu1.3 source package contains:
VER_BINUTILS := 2.37-5
MIN_VER_BINUTILS := 2.37-5
so in theory it could have been built again 2.37, which is still
sufficiently new.
"dpkg -s gcc-11-arm-linux-gnueabihf" says:
Depends: [...] binutils-arm-linux-gnueabihf (>= 2.38) [...]
so I guess it was actually built against 2.38, which is OK.
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
On Okt 03 2024, Geert Uytterhoeven wrote: > Hi Andreas, > > On Thu, Oct 3, 2024 at 10:42 AM Andreas Schwab <schwab@linux-m68k.org> wrote: >> On Okt 03 2024, Geert Uytterhoeven wrote: >> > | That ultimately depends on binutils support for SHF_GNU_RETAIN (2.36+). >> > >> > So binutils 2.38-4ubuntu2.6 is sufficiently new, but it doesn't work? >> >> It ultimately depends on the binutils version the compiler was built >> against. > > Is there an easy way to check that version? No. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."
On Thu, Oct 3, 2024 at 11:02 AM Andreas Schwab <schwab@linux-m68k.org> wrote: > > No. Is there a high enough minimum supported binutils per GCC major that we could at least rely upon? Perhaps in the future? I guess nothing we can really use, given https://gcc.gnu.org/install/prerequisites.html. Otherwise, does it mean we need a build-time test? Cheers, Miguel
On Okt 03 2024, Miguel Ojeda wrote: > Otherwise, does it mean we need a build-time test? A simple gcc version test definitely does not suffice. The suport for retain also depends on HAVE_INITFINI_ARRAY_SUPPORT, which is usually enabled by default (depends on glibc support, but that is much older), but can be disabled with --disable-initfini-array. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."
On Thu, Oct 3, 2024 at 2:11 PM Andreas Schwab <schwab@linux-m68k.org> wrote: > > A simple gcc version test definitely does not suffice. By build-time test, I meant compiling/running some small program to check whether the compiler supports the feature or not. Cheers, Miguel
On Thu, Oct 3, 2024 at 2:28 PM Miguel Ojeda <miguel.ojeda.sandonis@gmail.com> wrote: > > On Thu, Oct 3, 2024 at 2:11 PM Andreas Schwab <schwab@linux-m68k.org> wrote: > > > > A simple gcc version test definitely does not suffice. > > By build-time test, I meant compiling/running some small program to > check whether the compiler supports the feature or not. Ah, sorry, I missed the "definitely" in your message. I think I misunderstood your message. Cheers, Miguel
On Thu, Oct 3, 2024 at 2:11 PM Andreas Schwab <schwab@linux-m68k.org> wrote:
> On Okt 03 2024, Miguel Ojeda wrote:
>
> > Otherwise, does it mean we need a build-time test?
>
> A simple gcc version test definitely does not suffice.
>
> The suport for retain also depends on HAVE_INITFINI_ARRAY_SUPPORT, which
> is usually enabled by default (depends on glibc support, but that is
> much older), but can be disabled with --disable-initfini-array.
FTR, no --disable-initfini-array seen here:
$ arm-linux-gnueabihf-gcc-11 -v
Using built-in specs.
COLLECT_GCC=/usr/bin/arm-linux-gnueabihf-gcc-11
COLLECT_LTO_WRAPPER=/usr/lib/gcc-cross/arm-linux-gnueabihf/11/lto-wrapper
Target: arm-linux-gnueabihf
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
11.4.0-1ubuntu1~22.04'
--with-bugurl=file:///usr/share/doc/gcc-11/README.Bugs
--enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,m2
--prefix=/usr --with-gcc-major-version-only --program-suffix=-11
--enable-shared --enable-linker-build-id --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix --libdir=/usr/lib
--enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-libitm --disable-libquadmath --disable-libquadmath-support
--enable-plugin --enable-default-pie --with-system-zlib
--enable-libphobos-checking=release --without-target-system-zlib
--enable-multiarch --disable-sjlj-exceptions --with-arch=armv7-a+fp
--with-float=hard --with-mode=thumb --disable-werror
--enable-checking=release --build=x86_64-linux-gnu
--host=x86_64-linux-gnu --target=arm-linux-gnueabihf
--program-prefix=arm-linux-gnueabihf-
--includedir=/usr/arm-linux-gnueabihf/include
--with-build-config=bootstrap-lto-lean --enable-link-serialization=2
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 11.4.0 (Ubuntu 11.4.0-1ubuntu1~22.04)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
On Okt 03 2024, Geert Uytterhoeven wrote: > On Thu, Oct 3, 2024 at 2:11 PM Andreas Schwab <schwab@linux-m68k.org> wrote: >> On Okt 03 2024, Miguel Ojeda wrote: >> >> > Otherwise, does it mean we need a build-time test? >> >> A simple gcc version test definitely does not suffice. >> >> The suport for retain also depends on HAVE_INITFINI_ARRAY_SUPPORT, which >> is usually enabled by default (depends on glibc support, but that is >> much older), but can be disabled with --disable-initfini-array. > > FTR, no --disable-initfini-array seen here: --disable-initfini-array is the default for cross compilers. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."
Hi Andreas,
On Thu, Oct 3, 2024 at 2:34 PM Andreas Schwab <schwab@linux-m68k.org> wrote:
> On Okt 03 2024, Geert Uytterhoeven wrote:
> > On Thu, Oct 3, 2024 at 2:11 PM Andreas Schwab <schwab@linux-m68k.org> wrote:
> >> On Okt 03 2024, Miguel Ojeda wrote:
> >> > Otherwise, does it mean we need a build-time test?
> >>
> >> A simple gcc version test definitely does not suffice.
> >>
> >> The suport for retain also depends on HAVE_INITFINI_ARRAY_SUPPORT, which
> >> is usually enabled by default (depends on glibc support, but that is
> >> much older), but can be disabled with --disable-initfini-array.
> >
> > FTR, no --disable-initfini-array seen here:
>
> --disable-initfini-array is the default for cross compilers.
Apparently not for cross compilers targeting riscv64?
I.e. no --enable-initfini-array seen here:
$ riscv64-linux-gnu-gcc-11 -v
Using built-in specs.
COLLECT_GCC=/usr/bin/riscv64-linux-gnu-gcc-11
COLLECT_LTO_WRAPPER=/usr/lib/gcc-cross/riscv64-linux-gnu/11/lto-wrapper
Target: riscv64-linux-gnu
Configured with: ../src/configure -v --with-pkgversion='Ubuntu
11.4.0-1ubuntu1~22.04'
--with-bugurl=file:///usr/share/doc/gcc-11/README.Bugs
--enable-languages=c,ada,c++,go,d,fortran,objc,obj-c++,m2
--prefix=/usr --with-gcc-major-version-only --program-suffix=-11
--enable-shared --enable-linker-build-id --libexecdir=/usr/lib
--without-included-gettext --enable-threads=posix --libdir=/usr/lib
--enable-nls --with-sysroot=/ --enable-clocale=gnu
--enable-libstdcxx-debug --enable-libstdcxx-time=yes
--with-default-libstdcxx-abi=new --enable-gnu-unique-object
--disable-libitm --disable-libquadmath --disable-libquadmath-support
--enable-plugin --enable-default-pie --with-system-zlib
--enable-libphobos-checking=release --without-target-system-zlib
--enable-multiarch --disable-werror --disable-multilib
--with-arch=rv64gc --with-abi=lp64d --enable-checking=release
--build=x86_64-linux-gnu --host=x86_64-linux-gnu
--target=riscv64-linux-gnu --program-prefix=riscv64-linux-gnu-
--includedir=/usr/riscv64-linux-gnu/include
--with-build-config=bootstrap-lto-lean --enable-link-serialization=2
Thread model: posix
Supported LTO compression algorithms: zlib zstd
gcc version 11.4.0 (Ubuntu 11.4.0-1ubuntu1~22.04)
Gr{oetje,eeting}s,
Geert
--
Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org
In personal conversations with technical people, I call myself a hacker. But
when I'm talking to journalists I just say "programmer" or something like that.
-- Linus Torvalds
On Okt 03 2024, Geert Uytterhoeven wrote: > Hi Andreas, > > On Thu, Oct 3, 2024 at 2:34 PM Andreas Schwab <schwab@linux-m68k.org> wrote: >> On Okt 03 2024, Geert Uytterhoeven wrote: >> > On Thu, Oct 3, 2024 at 2:11 PM Andreas Schwab <schwab@linux-m68k.org> wrote: >> >> On Okt 03 2024, Miguel Ojeda wrote: >> >> > Otherwise, does it mean we need a build-time test? >> >> >> >> A simple gcc version test definitely does not suffice. >> >> >> >> The suport for retain also depends on HAVE_INITFINI_ARRAY_SUPPORT, which >> >> is usually enabled by default (depends on glibc support, but that is >> >> much older), but can be disabled with --disable-initfini-array. >> > >> > FTR, no --disable-initfini-array seen here: >> >> --disable-initfini-array is the default for cross compilers. > > Apparently not for cross compilers targeting riscv64? Yes, targets in the aarch64 era or newer enable initfini_array by default. Also, gcc 12+ generally defaults to --enable-initfini-array on Linux as well. -- Andreas Schwab, schwab@linux-m68k.org GPG Key fingerprint = 7578 EB47 D4E5 4D69 2510 2552 DF73 E780 A9DA AEC1 "And now for something completely different."
On Wed, Oct 2, 2024 at 9:25 AM Geert Uytterhoeven
<geert+renesas@glider.be> wrote:
>
> - * Optional: only supported since gcc >= 11, clang >= 13
> + * Optional: only supported since gcc >= 11 (partial), clang >= 13
Hmm... "partial" does not give much information -- perhaps something like:
* Optional: only supported since gcc >= 11 (partial, see
compiler-gcc.h), gcc >= 12, clang >= 13
What do you think?
With something like that:
Acked-by: Miguel Ojeda <ojeda@kernel.org>
Cheers,
Miguel
© 2016 - 2024 Red Hat, Inc.