From: Thomas Petazzoni Date: Tue, 30 Aug 2016 21:33:28 +0000 (+0200) Subject: gcc: remove BR2_GCC_ENABLE_TLS option X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=1bd02bc230e1b3b22ca3eb23fb3dcb91b878283a;p=buildroot.git gcc: remove BR2_GCC_ENABLE_TLS option The current BR2_GCC_ENABLE_TLS can cause users to make incorrect choices, and is not very useful. This options allows to decide whether we pass --enable-tls or --disable-tls to gcc, to enable or disable support for Thread Local Storage. Its behavior is: - The option is default to "y" but only exists if we're using uClibc/NPTL or glibc. - When we're using uClibc, the option can be disabled. So, in practice, this means that currently: - TLS support is always on for glibc - TLS support is on by default for uClibc/NPTL, but can be disabled in the configuration. This is in fact bad and causes the build failure reported in bug #7424 (this bug is still reproducible on master) - TLS support is always disabled for uClibc/no-thread and uClibc/linuxthreads. - TLS support is always disabled for musl. This does not cause any build failure, but musl can use TLS support, and therefore be more efficient. According to http://www.openwall.com/lists/musl/2012/10/04/1, "Note that if you've been building gcc with --disable-tls, __thread was already working but gets emulated (very poorly; it's slow and will abort() if it runs out of memory) through libgcc.". So, this commit completely removes the BR2_GCC_ENABLE_TLS and instead makes the right choice inside gcc.mk directly: - TLS support enabled for glibc, musl and uClibc/NPTL - TLS support in other cases, i.e uClibc/no-thread and uClibc/linuxthreads. We have intentionally *not* added the option to Config.in.legacy. Indeed, the new behavior is *exactly* the same as the older behavior, with the exception of: - People can no longer disable TLS support in uClibc/NPTL, which was anyway causing a build failure and therefore was not used. - TLS support is now enabled on musl, but people using musl already had BR2_GCC_ENABLE_TLS not set, so they wouldn't get the legacy warning. Fixes bug #7424. Signed-off-by: Thomas Petazzoni Reviewed-by: Arnout Vandecappelle (Essensium/Mind) --- diff --git a/package/gcc/Config.in.host b/package/gcc/Config.in.host index 72627147d3..aa0a698b56 100644 --- a/package/gcc/Config.in.host +++ b/package/gcc/Config.in.host @@ -154,14 +154,6 @@ config BR2_TOOLCHAIN_BUILDROOT_FORTRAN Fortran language and you want Fortran libraries to be installed on your target system. -config BR2_GCC_ENABLE_TLS - bool "Enable compiler tls support" if BR2_TOOLCHAIN_BUILDROOT_UCLIBC - default y - depends on BR2_PTHREADS_NATIVE || BR2_TOOLCHAIN_BUILDROOT_GLIBC - help - Enable the compiler to generate code for accessing - thread local storage variables - config BR2_GCC_ENABLE_LTO bool "Enable compiler link-time-optimization support" select BR2_BINUTILS_ENABLE_LTO diff --git a/package/gcc/gcc.mk b/package/gcc/gcc.mk index 39c3eebd21..82050b4a59 100644 --- a/package/gcc/gcc.mk +++ b/package/gcc/gcc.mk @@ -133,10 +133,13 @@ ifeq ($(BR2_sparc)$(BR2_sparc64),y) HOST_GCC_COMMON_CONF_OPTS += --disable-libsanitizer endif -ifeq ($(BR2_GCC_ENABLE_TLS),y) -HOST_GCC_COMMON_CONF_OPTS += --enable-tls -else +# TLS support is not needed on uClibc/no-thread and +# uClibc/linux-threads, otherwise, for all other situations (glibc, +# musl and uClibc/NPTL), we need it. +ifeq ($(BR2_TOOLCHAIN_BUILDROOT_UCLIBC)$(BR2_PTHREADS)$(BR2_PTHREADS_NONE),yy) HOST_GCC_COMMON_CONF_OPTS += --disable-tls +else +HOST_GCC_COMMON_CONF_OPTS += --enable-tls endif ifeq ($(BR2_GCC_ENABLE_LTO),y)