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Re: [Qemu-devel] [PATCH v3 1.3] build: compile translate.o with -fno-gcs
From: |
Andreas Färber |
Subject: |
Re: [Qemu-devel] [PATCH v3 1.3] build: compile translate.o with -fno-gcse option on GCC 4.6.x and 4.7.[012] |
Date: |
Wed, 28 Nov 2012 18:27:45 +0100 |
User-agent: |
Mozilla/5.0 (X11; Linux x86_64; rv:16.0) Gecko/20121025 Thunderbird/16.0.2 |
Am 28.11.2012 09:40, schrieb Paolo Bonzini:
> These versions of GCC require insane (>2GB) amounts of memory to compile
> translate.o. As a countermeasure, disable the culprit optimization pass.
> This should fix the buildbot failure for default_x86_64_fedora16. Anyway
> this is a good thing to do because people will try to compile 1.3 with
> less than 2GB of memory and complain.
>
> Signed-off-by: Paolo Bonzini <address@hidden>
Tested-by: Andreas Färber <address@hidden>
> ---
> Makefile.target | 3 +++
> configure | 16 ++++++++++++++++
> 2 files changed, 19 insertions(+)
>
> diff --git a/Makefile.target b/Makefile.target
> index 8b658c0..927347b 100644
> --- a/Makefile.target
> +++ b/Makefile.target
> @@ -143,6 +143,9 @@ GENERATED_HEADERS += hmp-commands.h qmp-commands-old.h
>
> endif # CONFIG_SOFTMMU
>
> +# Workaround for http://gcc.gnu.org/PR55489, see configure.
> +%/translate.o: QEMU_CFLAGS += $(TRANSLATE_OPT_CFLAGS)
> +
> nested-vars += obj-y
>
> # This resolves all nested paths, so it must come last
> diff --git a/configure b/configure
> index 780b19a..994f731 100755
> --- a/configure
> +++ b/configure
> @@ -1183,6 +1183,21 @@ for flag in $gcc_flags; do
> fi
> done
>
> +# Workaround for http://gcc.gnu.org/PR55489. Happens with -fPIE/-fPIC and
> +# large functions that use global variables. The bug is in all releases of
> +# GCC, but it became particularly acute in 4.6.x and 4.7.x. It is fixed in
> +# 4.7.3 and 4.8.0. We should be able to delete this at the end of 2013.
> +cat > $TMPC << EOF
> +#if __GNUC__ == 4 && (__GNUC_MINOR__ == 6 || (__GNUC_MINOR__ == 7 &&
> __GNUC_PATCHLEVEL__ <= 2))
FWIW this line looks overly long.
> +int main(void) { return 0; }
> +#else
> +#error No bug in this compiler.
Interesting logic. :)
Andreas
> +#endif
> +EOF
> +if compile_prog "-Werror -fno-gcse" "" ; then
> + TRANSLATE_OPT_CFLAGS=-fno-gcse
> +fi
> +
> if test "$static" = "yes" ; then
> if test "$pie" = "yes" ; then
> echo "static and pie are mutually incompatible"
> @@ -3662,6 +3677,7 @@ echo "LIBS_TOOLS+=$libs_tools" >> $config_host_mak
> echo "EXESUF=$EXESUF" >> $config_host_mak
> echo "LIBS_QGA+=$libs_qga" >> $config_host_mak
> echo "POD2MAN=$POD2MAN" >> $config_host_mak
> +echo "TRANSLATE_OPT_CFLAGS=$TRANSLATE_OPT_CFLAGS" >> $config_host_mak
>
> # generate list of library paths for linker script
>
>
--
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