diff --git a/eclass/dot-a.eclass b/eclass/dot-a.eclass
new file mode 100644
index 0000000000000..20a0fa1dfc206
--- /dev/null
+++ b/eclass/dot-a.eclass
@@ -0,0 +1,124 @@
+# Copyright 2025 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+# @ECLASS: dot-a.eclass
+# @MAINTAINER:
+# Toolchain
+# Toolchain Ninjas <toolchain@gentoo.org>
+# @AUTHOR:
+# Sam James <sam@gentoo.org>
+# Eli Schwartz <eschwartz@gentoo.org>
+# @SUPPORTED_EAPIS: 8
+# @BLURB: Functions to handle stripping LTO bytecode out of static archives. +# @DESCRIPTION:
+# This eclass provides functions to strip LTO bytecode out of static archives
+# (.a files).
+#
+# Static libraries when built with LTO will contain LTO bytecode which is
+# not portable across compiler versions or compiler vendors. To avoid pessimising
+# the library and always filtering LTO, we can build it with -ffat-lto-objects
+# instead, which builds some components twice. The installed part will then +# have the LTO contents stripped out, leaving the regular objects in the
+# static archive.
+#
+# Use should be passing calling lto-guarantee-fat before configure-time
+# and calling strip-lto-bytecode after installation.
+#
+# @EXAMPLE:
+# @CODE
+#
+# inherit dot-a
+#
+# src_configure() {
+# lto-guarantee-fat
+# econf
+# }
+#
+# src_install() {
+# default
+# strip-lto-bytecode
+# }
+case ${EAPI} in
+ 8) ;;
+ *) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;;
+esac
+
+if [[ -z ${_DOT_A_ECLASS} ]] ; then
+_DOT_A_ECLASS=1
+
+inherit flag-o-matic toolchain-funcs
+
+# TODO: QA check
+
+# @FUNCTION: lto-guarantee-fat
+# @DESCRIPTION:
+# If LTO is enabled, appends -ffat-lto-objects or any other flags needed
+# to provide fat LTO objects.
+lto-guarantee-fat() {
+ tc-is-lto || return
+
+ # We add this for all languages as LTO obviously can't be done
+ # if different compilers are used for e.g. C vs C++ anyway.
+ append-flags $(test-flags-CC -ffat-lto-objects)
+}
+
+# @FUNCTION: strip-lto-bytecode
+# @USAGE: [library|directory] [...]
+# @DESCRIPTION:
+# Strips LTO bytecode from libraries (static archives) passed as arguments. +# Defaults to operating on ${ED} as a whole if no arguments are passed.
+#
+# As an optimisation, if USE=static-libs exists for a package and is disabled,
+# the default-searching behaviour with no arguments is suppressed. +strip-lto-bytecode() {
+ tc-is-lto || return
+
+ local files=()
+
+ if [[ ${#} -eq 0 ]]; then
+ if ! in_iuse static-libs || use static-libs ; then
+ # maybe we are USE=static-libs. Alternatively, maybe the ebuild doesn't
+ # offer such a choice. In both cases, the user specified the function,
+ # so we expect to be called on *something*, but nothing was explicitly
+ # passed. Try scanning ${ED} automatically.
+ set -- "${ED}"
+ fi
+ fi
+
+ # Check if any of our arguments are directories to be recursed
+ # into.
+ local arg
+ for arg in "$@" ; do
+ if [[ -d ${arg} ]] ; then
+ mapfile -t -d '' -O "${#files[@]}" files < <(find "${arg}" -type f -iname '*.a' -print0)
+ else
+ files+=( "${arg}" )
+ fi
+ done
+
+ toolchain_type=
+ tc-is-gcc && toolchain_type=gnu
+ tc-is-clang && toolchain_type=llvm
+
+ local file
+ for file in "${files[@]}" ; do
+ case ${toolchain_type} in
+ gnu)
+ $(tc-getSTRIP) \
+ -R .gnu.lto_* \
+ -R .gnu.debuglto_* \
+ -N __gnu_lto_v1 \
+ "${file}" || die "Stripping bytecode in ${file} failed"
+ ;;
+ llvm)
+ llvm-bitcode-strip \
+ -r "${file}" \
+ -o "${file}" || die "Stripping bytecode in ${file} failed"
+ ;;
+ *)
+ ;;
+ esac
+ done
+}
+
+fi
Michał Górny <mgorny@gentoo.org> writes:
[...]
+ local arg
+ for arg in "$@" ; do
+ if [[ -d ${arg} ]] ; then
+ mapfile -t -d '' -O "${#files[@]}" files < <(find "${arg}" -type f -iname '*.a' -print0)
+ else
+ files+=( "${arg}" )
+ fi
+ done
Why not just pass all arguments to find(1)? If you pass a file path to
it, it will just return that file, i.e.:
mapfile -t -d '' files < <(find -H "${@}" -type f -iname '*.a' -print0)
('-H' to follow symbolic links if passed directly in "$@")
Oh! Good point. Let me try that.
Hi,
Sorry for not looking earlier.
On Fri, 2025-05-02 at 21:13 +0100, Sam James wrote:
diff --git a/eclass/dot-a.eclass b/eclass/dot-a.eclass
new file mode 100644
index 0000000000000..20a0fa1dfc206
--- /dev/null
+++ b/eclass/dot-a.eclass
@@ -0,0 +1,124 @@
+# Copyright 2025 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+# @ECLASS: dot-a.eclass
+# @MAINTAINER:
+# Toolchain
+# Toolchain Ninjas <toolchain@gentoo.org>
You've got "toolchain" twice.
+# @AUTHOR:
+# Sam James <sam@gentoo.org>
+# Eli Schwartz <eschwartz@gentoo.org>
+# @SUPPORTED_EAPIS: 8
+# @BLURB: Functions to handle stripping LTO bytecode out of static archives.
+# @DESCRIPTION:
+# This eclass provides functions to strip LTO bytecode out of static archives
+# (.a files).
+#
+# Static libraries when built with LTO will contain LTO bytecode which is >> +# not portable across compiler versions or compiler vendors. To avoid pessimising
+# the library and always filtering LTO, we can build it with -ffat-lto-objects
+# instead, which builds some components twice. The installed part will then >> +# have the LTO contents stripped out, leaving the regular objects in the
+# static archive.
+#
+# Use should be passing calling lto-guarantee-fat before configure-time
+# and calling strip-lto-bytecode after installation.
Do I understand correctly that this is to be always used when you're installing static libraries? Or are there more specific criteria?
Perhaps that'd be worth including in the doc.
+#
+# @EXAMPLE:
+# @CODE
+#
+# inherit dot-a
+#
+# src_configure() {
+# lto-guarantee-fat
+# econf
+# }
+#
+# src_install() {
+# default
+# strip-lto-bytecode
+# }
+case ${EAPI} in
+ 8) ;;
+ *) die "${ECLASS}: EAPI ${EAPI:-0} not supported" ;;
+esac
+
+if [[ -z ${_DOT_A_ECLASS} ]] ; then
+_DOT_A_ECLASS=1
+
+inherit flag-o-matic toolchain-funcs
+
+# TODO: QA check
+
+# @FUNCTION: lto-guarantee-fat
+# @DESCRIPTION:
+# If LTO is enabled, appends -ffat-lto-objects or any other flags needed
+# to provide fat LTO objects.
+lto-guarantee-fat() {
+ tc-is-lto || return
+
+ # We add this for all languages as LTO obviously can't be done
+ # if different compilers are used for e.g. C vs C++ anyway.
+ append-flags $(test-flags-CC -ffat-lto-objects)
+}
+
+# @FUNCTION: strip-lto-bytecode
+# @USAGE: [library|directory] [...]
+# @DESCRIPTION:
+# Strips LTO bytecode from libraries (static archives) passed as arguments. >> +# Defaults to operating on ${ED} as a whole if no arguments are passed.
+#
+# As an optimisation, if USE=static-libs exists for a package and is disabled,
+# the default-searching behaviour with no arguments is suppressed.
+strip-lto-bytecode() {
+ tc-is-lto || return
+
+ local files=()
+
+ if [[ ${#} -eq 0 ]]; then
+ if ! in_iuse static-libs || use static-libs ; then
+ # maybe we are USE=static-libs. Alternatively, maybe the ebuild doesn't
+ # offer such a choice. In both cases, the user specified the function,
+ # so we expect to be called on *something*, but nothing was explicitly
+ # passed. Try scanning ${ED} automatically.
+ set -- "${ED}"
+ fi
+ fi
+
+ # Check if any of our arguments are directories to be recursed
+ # into.
+ local arg
+ for arg in "$@" ; do
+ if [[ -d ${arg} ]] ; then
+ mapfile -t -d '' -O "${#files[@]}" files < <(find "${arg}" -type f -iname '*.a' -print0)
+ else
+ files+=( "${arg}" )
+ fi
+ done
Why not just pass all arguments to find(1)? If you pass a file path to
it, it will just return that file, i.e.:
mapfile -t -d '' files < <(find -H "${@}" -type f -iname '*.a' -print0)
('-H' to follow symbolic links if passed directly in "$@")
+
+ toolchain_type=
+ tc-is-gcc && toolchain_type=gnu
+ tc-is-clang && toolchain_type=llvm
+
+ local file
+ for file in "${files[@]}" ; do
+ case ${toolchain_type} in
+ gnu)
+ $(tc-getSTRIP) \
+ -R .gnu.lto_* \
+ -R .gnu.debuglto_* \
+ -N __gnu_lto_v1 \
+ "${file}" || die "Stripping bytecode in ${file} failed"
+ ;;
Technically, strip accepts multiple files, but I can guess there's
no point in optimizing the GNU branch here.
+ llvm)
+ llvm-bitcode-strip \
+ -r "${file}" \
+ -o "${file}" || die "Stripping bytecode in ${file} failed"
+ ;;
+ *)
+ ;;
+ esac
+ done
+}
+
+fi
Sam James <sam@gentoo.org> writes:
Michał Górny <mgorny@gentoo.org> writes:
[...]
+ local arg
+ for arg in "$@" ; do
+ if [[ -d ${arg} ]] ; then
+ mapfile -t -d '' -O "${#files[@]}" files < <(find "${arg}" -type f -iname '*.a' -print0)
+ else
+ files+=( "${arg}" )
+ fi
+ done
Why not just pass all arguments to find(1)? If you pass a file path to
it, it will just return that file, i.e.:
mapfile -t -d '' files < <(find -H "${@}" -type f -iname '*.a' -print0)
('-H' to follow symbolic links if passed directly in "$@")
Oh! Good point. Let me try that.
This breaks some of the tests because we do some direct testing on .o
files. But I can't think of why a package would do that besides
toolchain packages where special care will be needed anyway, so I'll
adjust the tests.
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