Re: [Buildroot] [PATCH v3 8/8] package/pkg-autotools: patch libtool to support ARM FDPIC

From: "Yann E. MORIN" <yann.morin.1998@free.fr>
To: Ben Wolsieffer <ben.wolsieffer@hefring.com>
Cc: Vladimir Murzin <vladimir.murzin@arm.com>,
	Thomas Petazzoni <thomas.petazzoni@bootlin.com>,
	buildroot@buildroot.org, Romain Naour <romain.naour@gmail.com>,
	Giulio Benetti <giulio.benetti@benettiengineering.com>,
	Thomas De Schampheleire <thomas.de_schampheleire@nokia.com>
Subject: Re: [Buildroot] [PATCH v3 8/8] package/pkg-autotools: patch libtool to support ARM FDPIC
Date: Sun, 16 Apr 2023 21:01:31 +0200	[thread overview]
Message-ID: <20230416190131.GD2819@scaer> (raw)
In-Reply-To: <20220819151734.926106-9-Ben.Wolsieffer@hefring.com>

Ben, All,

On 2022-08-19 11:17 -0400, Ben Wolsieffer spake thusly:
> Patch the target matching code in libtool to understand
> arm-*-uclinuxfdpiceabi targets. To avoid the need to run autoreconf,
> this patching must be performed in the configure script.
> 
> Without this patch, libtool refuses to build ARM FDPIC shared libraries.
> This is especially important because NPTL thread-local storage is broken
> in static libraries that are linked into dynamic FDPIC executables.

If static build is known to be broken with FDPIC, then maybe we should
just forbid it:

    config BR2_STATIC_LIBS
        bool "static only"
        depends on BR2_BINFMT_SUPPORTS_STATIC
        depends on !BR2_TOOLCHAIN_USES_GLIBC

    comment "static only needs a toolchain w/ uclibc or musl"
        depends on BR2_BINFMT_SUPPORTS_STATIC
        depends on BR2_TOOLCHAIN_USES_GLIBC

    config BR2_SHARED_LIBS
        bool "shared only"
        depends on BR2_BINFMT_SUPPORTS_SHARED

    config BR2_SHARED_STATIC_LIBS
        bool "both static and shared"
        depends on BR2_BINFMT_SUPPORTS_STATIC && BR2_BINFMT_SUPPORTS_SHARED

BR2_BINFMT_SUPPORTS_STATIC would be a new symbol that BR2_BINFMT_ELF
and BR2_BINFMT_FLAT would select, but not BR2_BINFMT_FDPIC.

Regards,
Yann E. MORIN.

> Signed-off-by: Ben Wolsieffer <Ben.Wolsieffer@hefring.com>
> ---
>  package/pkg-autotools.mk | 17 +++++++++++++++++
>  1 file changed, 17 insertions(+)
> 
> diff --git a/package/pkg-autotools.mk b/package/pkg-autotools.mk
> index b6224b349d..60e70a6e2f 100644
> --- a/package/pkg-autotools.mk
> +++ b/package/pkg-autotools.mk
> @@ -87,6 +87,16 @@ define CONFIGURE_FIX_POWERPC64_HOOK
>  	support/scripts/fix-configure-powerpc64.sh $($(PKG)_DIR)
>  endef
>  
> +#
> +# Hook to add support for arm-*-uclinuxfdpiceabi to the configure script
> +#
> +define CONFIGURE_FIX_UCLINUXFDPICEABI_HOOK
> +	@$(call MESSAGE,"Adding uclinuxfdpiceabi to configure")
> +	find $($(PKG)_DIR) -name configure \
> +		-exec grep -qF 'Generated by GNU Autoconf' {} \; \
> +		-exec sed -Ei 's#((\s|^)linux\*\B)#\1 | uclinuxfdpiceabi#' '{}' \;
> +endef
> +
>  #
>  # Hook to gettextize the package if needed
>  #
> @@ -269,6 +279,13 @@ ifneq ($$(filter powerpc64%,$$(if $$(filter target,$(4)),$$(ARCH),$$(HOSTARCH)))
>  $(2)_PRE_CONFIGURE_HOOKS += CONFIGURE_FIX_POWERPC64_HOOK
>  endif
>  
> +# Append a configure hook if building for ARM with FDPIC enabled.
> +# Must be added after other pre-configure hooks that might regenerate the
> +# configure script and overwrite the changes made here.
> +ifeq ($(BR2_arm)$(BR2_armeb):$(BR2_BINFMT_FDPIC),y:y)
> +$(2)_PRE_CONFIGURE_HOOKS += CONFIGURE_FIX_UCLINUXFDPICEABI_HOOK
> +endif
> +
>  #
>  # Build step. Only define it if not already defined by the package .mk
>  # file.
> -- 
> 2.37.0
> 
> _______________________________________________
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> buildroot@buildroot.org
> https://lists.buildroot.org/mailman/listinfo/buildroot

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