[gentoo-commits] repo/gentoo:master commit in: sys-devel/gcc/, sys-devel/gcc/files/

["Sam James" <sam@gentoo.org>]

commit:     1e10614cf5b563340143230bae47c10c45300196
Author:     Sam James <sam <AT> gentoo <DOT> org>
AuthorDate: Wed May  3 12:31:04 2023 +0000
Commit:     Sam James <sam <AT> gentoo <DOT> org>
CommitDate: Wed May  3 12:31:04 2023 +0000
URL:        https://gitweb.gentoo.org/repo/gentoo.git/commit/?id=1e10614c

sys-devel/gcc: backport libstdc++ UB fix for 13

May keyword this version later or may wait until next snapshot in a few days,
we'll see.

Bug: https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109703
Signed-off-by: Sam James <sam <AT> gentoo.org>

 .../gcc/files/gcc-13-PR109703-unreachable.patch    | 54 +++++++++++++++++++
 sys-devel/gcc/gcc-13.1.1_p20230429-r1.ebuild       | 63 ++++++++++++++++++++++
 2 files changed, 117 insertions(+)

diff --git a/sys-devel/gcc/files/gcc-13-PR109703-unreachable.patch b/sys-devel/gcc/files/gcc-13-PR109703-unreachable.patch
new file mode 100644
index 000000000000..f7c7c9f60a70
--- /dev/null
+++ b/sys-devel/gcc/files/gcc-13-PR109703-unreachable.patch
@@ -0,0 +1,54 @@
+https://gcc.gnu.org/bugzilla/show_bug.cgi?id=109703
+
+From d50f2599d7b23bdba05a9102645d082ed9bcb05f Mon Sep 17 00:00:00 2001
+From: Kefu Chai <kefu.chai@scylladb.com>
+Date: Mon, 1 May 2023 21:24:26 +0100
+Subject: [PATCH] libstdc++: Set _M_string_length before calling _M_dispose()
+ [PR109703]
+
+This always sets _M_string_length in the constructor for ranges of input
+iterators, such as stream iterators.
+
+We copy from the source range to the local buffer, and then repeatedly
+reallocate a larger one if necessary. When disposing the old buffer,
+_M_is_local() is used to tell if the buffer is the local one or not (and
+so must be deallocated). In addition to comparing the buffer address
+with the local buffer, _M_is_local() has an optimization hint so that
+the compiler knows that for a string using the local buffer, there is an
+invariant that _M_string_length <= _S_local_capacity (added for PR109299
+via r13-6915-gbf78b43873b0b7).  But we failed to set _M_string_length in
+the constructor taking a pair of iterators, so the invariant might not
+hold, and __builtin_unreachable() is reached. This causes UBsan errors,
+and potentially misoptimization.
+
+To ensure the invariant holds, _M_string_length is initialized to zero
+before doing anything else, so that _M_is_local() doesn't see an
+uninitialized value.
+
+This issue only surfaces when constructing a string with a range of
+input iterator, and the uninitialized _M_string_length happens to be
+greater than _S_local_capacity, i.e., 15 for the std::string
+specialization.
+
+libstdc++-v3/ChangeLog:
+
+	PR libstdc++/109703
+	* include/bits/basic_string.h (basic_string(Iter, Iter, Alloc)):
+	Initialize _M_string_length.
+
+Signed-off-by: Kefu Chai <kefu.chai@scylladb.com>
+Co-authored-by: Jonathan Wakely <jwakely@redhat.com>
+(cherry picked from commit cbf6c7a1d16490a1e63e9a5ce00e9a5c44c4c2f2)
+--- a/libstdc++-v3/include/bits/basic_string.h
++++ b/libstdc++-v3/include/bits/basic_string.h
+@@ -760,7 +760,7 @@ _GLIBCXX_BEGIN_NAMESPACE_CXX11
+ 	_GLIBCXX20_CONSTEXPR
+         basic_string(_InputIterator __beg, _InputIterator __end,
+ 		     const _Alloc& __a = _Alloc())
+-	: _M_dataplus(_M_local_data(), __a)
++	: _M_dataplus(_M_local_data(), __a), _M_string_length(0)
+ 	{
+ #if __cplusplus >= 201103L
+ 	  _M_construct(__beg, __end, std::__iterator_category(__beg));
+-- 
+2.31.1

diff --git a/sys-devel/gcc/gcc-13.1.1_p20230429-r1.ebuild b/sys-devel/gcc/gcc-13.1.1_p20230429-r1.ebuild
new file mode 100644
index 000000000000..9aa2b8645de1
--- /dev/null
+++ b/sys-devel/gcc/gcc-13.1.1_p20230429-r1.ebuild
@@ -0,0 +1,63 @@
+# Copyright 1999-2023 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+TOOLCHAIN_PATCH_DEV="sam"
+PATCH_VER="2"
+PATCH_GCC_VER="13.2.0"
+MUSL_VER="1"
+MUSL_GCC_VER="13.2.0"
+
+if [[ $(ver_cut 3) == 9999 ]] ; then
+	MY_PV_2=$(ver_cut 2)
+	if [[ ${MY_PV_2} == 0 ]] ; then
+		MY_PV_2=0
+	else
+		MY_PV_2=$(($(ver_cut 2) - 1))
+	fi
+
+	# e.g. 12.2.9999 -> 12.1.1
+	TOOLCHAIN_GCC_PV=$(ver_cut 1).${MY_PV_2}.$(($(ver_cut 3) - 9998))
+elif [[ -n ${TOOLCHAIN_GCC_RC} ]] ; then
+	# Cheesy hack for RCs
+	MY_PV=$(ver_cut 1).$((($(ver_cut 2) + 1))).$((($(ver_cut 3) - 1)))-RC-$(ver_cut 5)
+	MY_P=${PN}-${MY_PV}
+	GCC_TARBALL_SRC_URI="mirror://gcc/snapshots/${MY_PV}/${MY_P}.tar.xz"
+	TOOLCHAIN_SET_S=no
+	S="${WORKDIR}"/${MY_P}
+fi
+
+inherit toolchain
+
+# Needs to be after inherit (for now?), bug #830908
+EGIT_BRANCH=releases/gcc-$(ver_cut 1)
+
+# Don't keyword live ebuilds
+#if ! tc_is_live && [[ -z ${TOOLCHAIN_USE_GIT_PATCHES} ]] ; then
+#	KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86"
+#fi
+
+if [[ ${CATEGORY} != cross-* ]] ; then
+	# Technically only if USE=hardened *too* right now, but no point in complicating it further.
+	# If GCC is enabling CET by default, we need glibc to be built with support for it.
+	# bug #830454
+	RDEPEND="elibc_glibc? ( sys-libs/glibc[cet(-)?] )"
+	DEPEND="${RDEPEND}"
+	BDEPEND=">=${CATEGORY}/binutils-2.30[cet(-)?]"
+fi
+
+src_prepare() {
+	local p upstreamed_patches=(
+		# add them here
+	)
+	for p in "${upstreamed_patches[@]}"; do
+		rm -v "${WORKDIR}/patch/${p}" || die
+	done
+
+	toolchain_src_prepare
+
+	eapply "${FILESDIR}"/${PN}-13-fix-cross-fixincludes.patch
+	eapply "${FILESDIR}"/${PN}-13-PR109703-unreachable.patch
+	eapply_user
+}