[Buildroot] [PATCH 05/21] icu: remove BR2_ARCH_HAS_ATOMICS dependency
Yann E. MORIN
yann.morin.1998 at free.fr
Mon Jan 25 18:42:57 UTC 2016
Thomas, All,
On 2016-01-25 00:07 +0100, Thomas Petazzoni spake thusly:
> The BR2_ARCH_HAS_ATOMICS was added because on ARC, atomic instructions
> may not be provided by the architecture and therefore the compiler
> does not provide the __sync_*() built-ins.
>
> However, since then, icu was changed and is now able to use C++11
> atomics, or even no atomic operations at all. In fact, icu will:
>
> * If possible, it will use C++11 atomics, which internally rely on
> the __atomic built-ins. These are available since gcc 4.7, and all
> architectures provide it. On some architectures, you *must* link
> with libatomic, on some other architectures, they are available
> built-in, but in all cases, linking against libatomic does not
> harm. Thanks to this, even ARC with no atomic support (which was
> the original reason for adding the BR2_ARCH_HAS_ATOMICS) dependency
> builds fine, provided -latomic is added to LIBS.
>
> * If C++11 atomics are not available, then it falls back to
> __sync_*() built-ins, which allows compilers older than 4.7 to be
> supported.
>
> * If really no atomic mechanism is available, then it falls back to a
> basic implementation based on a mutex.
>
> Conclusion:
>
> - The BR2_ARCH_HAS_ATOMICS dependency is no longer needed.
>
> - We need to link with -latomic when gcc >= 4.7 is used.
>
> Note that reverse dependencies of icu are also changed accordingly.
>
> Signed-off-by: Thomas Petazzoni <thomas.petazzoni at free-electrons.com>
Reviewed-by: "Yann E. MORIN" <yann.morin.1998 at free.fr>
Regards,
Yann E. MORIN.
> ---
> package/beecrypt/Config.in | 2 --
> package/cppcms/Config.in | 1 -
> package/icu/Config.in | 2 --
> package/icu/icu.mk | 8 ++++++++
> package/php/Config.ext | 2 --
> package/qt-webkit-kiosk/Config.in | 1 -
> package/qt5/qt5base/Config.in | 1 -
> package/qt5/qt5webkit/Config.in | 1 -
> 8 files changed, 8 insertions(+), 10 deletions(-)
>
> diff --git a/package/beecrypt/Config.in b/package/beecrypt/Config.in
> index fc93a77..069f3d5 100644
> --- a/package/beecrypt/Config.in
> +++ b/package/beecrypt/Config.in
> @@ -16,7 +16,6 @@ config BR2_PACKAGE_BEECRYPT_CPP
> depends on BR2_INSTALL_LIBSTDCPP
> depends on BR2_USE_WCHAR # icu
> depends on !BR2_BINFMT_FLAT # icu
> - depends on BR2_ARCH_HAS_ATOMICS # icu
> depends on !BR2_STATIC_LIBS
> select BR2_PACKAGE_ICU
> help
> @@ -24,7 +23,6 @@ config BR2_PACKAGE_BEECRYPT_CPP
>
> comment "C++ support needs a toolchain w/ C++, wchar, dynamic libraries"
> depends on !BR2_BINFMT_FLAT
> - depends on BR2_ARCH_HAS_ATOMICS
> depends on !BR2_INSTALL_LIBSTDCPP || !BR2_USE_WCHAR \
> || BR2_STATIC_LIBS
>
> diff --git a/package/cppcms/Config.in b/package/cppcms/Config.in
> index 85ba118..79f5474 100644
> --- a/package/cppcms/Config.in
> +++ b/package/cppcms/Config.in
> @@ -26,7 +26,6 @@ if BR2_PACKAGE_CPPCMS
> config BR2_PACKAGE_CPPCMS_ICU
> bool "enable icu support"
> depends on !BR2_BINFMT_FLAT # icu
> - depends on BR2_ARCH_HAS_ATOMICS # icu
> select BR2_PACKAGE_ICU
> help
> Using ICU allows advanced localization features into CppCMS,
> diff --git a/package/icu/Config.in b/package/icu/Config.in
> index 4d47c32..d31c1fa 100644
> --- a/package/icu/Config.in
> +++ b/package/icu/Config.in
> @@ -7,7 +7,6 @@ config BR2_PACKAGE_ICU
> # file, and it cannot easily be changed to generate FLAT
> # format.
> depends on !BR2_BINFMT_FLAT
> - depends on BR2_ARCH_HAS_ATOMICS
> help
> International Components for Unicode.
>
> @@ -28,6 +27,5 @@ endif
>
> comment "icu needs a toolchain w/ C++, wchar, threads"
> depends on !BR2_BINFMT_FLAT
> - depends on BR2_ARCH_HAS_ATOMICS
> depends on !BR2_INSTALL_LIBSTDCPP || !BR2_USE_WCHAR || \
> !BR2_TOOLCHAIN_HAS_THREADS
> diff --git a/package/icu/icu.mk b/package/icu/icu.mk
> index 5604504..7bc7f93 100644
> --- a/package/icu/icu.mk
> +++ b/package/icu/icu.mk
> @@ -17,6 +17,14 @@ ICU_CONF_OPTS = \
> --with-cross-build=$(HOST_ICU_DIR)/source \
> --disable-samples \
> --disable-tests
> +
> +# With gcc >= 4.7, icu prefers to use C++11 atomics, which rely on the
> +# __atomic builtins. On certain architectures, this requires linking
> +# with libatomic.
> +ifeq ($(BR2_TOOLCHAIN_GCC_AT_LEAST_4_7),y)
> +ICU_CONF_ENV += LIBS="-latomic"
> +endif
> +
> HOST_ICU_CONF_OPTS = \
> --disable-samples \
> --disable-tests \
> diff --git a/package/php/Config.ext b/package/php/Config.ext
> index c044e45..ee51030 100644
> --- a/package/php/Config.ext
> +++ b/package/php/Config.ext
> @@ -207,13 +207,11 @@ config BR2_PACKAGE_PHP_EXT_INTL
> depends on BR2_USE_WCHAR
> depends on !BR2_BINFMT_FLAT # icu
> depends on BR2_TOOLCHAIN_HAS_THREADS # icu
> - depends on BR2_ARCH_HAS_ATOMICS # icu
> help
> Internationalization support
>
> comment "intl support needs a toolchain w/ C++, wchar, threads"
> depends on !BR2_BINFMT_FLAT
> - depends on BR2_ARCH_HAS_ATOMICS
> depends on !BR2_INSTALL_LIBSTDCPP || !BR2_USE_WCHAR || !BR2_TOOLCHAIN_HAS_THREADS
>
> config BR2_PACKAGE_PHP_EXT_MBSTRING
> diff --git a/package/qt-webkit-kiosk/Config.in b/package/qt-webkit-kiosk/Config.in
> index 51383f0..32952d7 100644
> --- a/package/qt-webkit-kiosk/Config.in
> +++ b/package/qt-webkit-kiosk/Config.in
> @@ -8,7 +8,6 @@ config BR2_PACKAGE_QT_WEBKIT_KIOSK
> select BR2_PACKAGE_QT5MULTIMEDIA
> depends on !BR2_STATIC_LIBS # qt5webkit
> depends on BR2_PACKAGE_QT5_JSCORE_AVAILABLE # qt5webkit
> - depends on BR2_ARCH_HAS_ATOMICS # qt5webkit
> depends on !BR2_BINFMT_FLAT # qt5webkit
> help
> Simple kiosk-mode browser powered by Qt5Webkit
> diff --git a/package/qt5/qt5base/Config.in b/package/qt5/qt5base/Config.in
> index 7cadcb2..64a7f65 100644
> --- a/package/qt5/qt5base/Config.in
> +++ b/package/qt5/qt5base/Config.in
> @@ -259,7 +259,6 @@ config BR2_PACKAGE_QT5BASE_DBUS
> config BR2_PACKAGE_QT5BASE_ICU
> bool "Enable ICU support"
> select BR2_PACKAGE_ICU
> - depends on BR2_ARCH_HAS_ATOMICS # icu
> depends on !BR2_BINFMT_FLAT # icu
> help
> This option enables ICU support in Qt5. This is for example
> diff --git a/package/qt5/qt5webkit/Config.in b/package/qt5/qt5webkit/Config.in
> index eee82e8..96d97cc 100644
> --- a/package/qt5/qt5webkit/Config.in
> +++ b/package/qt5/qt5webkit/Config.in
> @@ -9,7 +9,6 @@ config BR2_PACKAGE_QT5WEBKIT
> # This module does not support static linking
> depends on !BR2_STATIC_LIBS
> depends on BR2_PACKAGE_QT5_JSCORE_AVAILABLE
> - depends on BR2_ARCH_HAS_ATOMICS # icu
> depends on !BR2_BINFMT_FLAT # icu
> help
> Qt is a cross-platform application and UI framework for
> --
> 2.6.4
>
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