dev-libs/libpcre: fix attributes w/ clang 16

pcre_exec was optimised, despite the attributes asking it not to, because
Clang 16 recognises different tokens.

Thanks to Zhixu Liu for the wonderful analysis.

Closes: https://bugs.gentoo.org/910188
Signed-off-by: Sam James <sam@gentoo.org>

2 files changed, 124 insertions, 0 deletions

diff --git a/dev-libs/libpcre/files/libpcre-8.45-fix-stack-size-detection.patch b/dev-libs/libpcre/files/libpcre-8.45-fix-stack-size-detection.patch
new file mode 100644
index 000000000000..2b5af062d36a
--- /dev/null
+++ b/dev-libs/libpcre/files/libpcre-8.45-fix-stack-size-detection.patch
@@ -0,0 +1,18 @@
+https://bugs.exim.org/show_bug.cgi?id=2173#c4
+https://bugs.gentoo.org/910188
+https://github.com/MariaDB/server/pull/2700
+--- a/pcre_exec.c
++++ b/pcre_exec.c
+@@ -509,6 +509,12 @@
+                  (e.g. stopped by repeated call or recursion limit)
+ */
+ 
++#ifdef __GNUC__
++static int
++match(REGISTER PCRE_PUCHAR eptr, REGISTER const pcre_uchar *ecode,
++  PCRE_PUCHAR mstart, int offset_top, match_data *md, eptrblock *eptrb,
++  unsigned int rdepth) __attribute__((optnone,noinline,noclone));
++#endif
+ static int
+ match(REGISTER PCRE_PUCHAR eptr, REGISTER const pcre_uchar *ecode,
+   PCRE_PUCHAR mstart, int offset_top, match_data *md, eptrblock *eptrb,
diff --git a/dev-libs/libpcre/libpcre-8.45-r2.ebuild b/dev-libs/libpcre/libpcre-8.45-r2.ebuild
new file mode 100644
index 000000000000..0f71104bd917
--- /dev/null
+++ b/dev-libs/libpcre/libpcre-8.45-r2.ebuild
@@ -0,0 +1,106 @@
+# Copyright 1999-2023 Gentoo Authors
+# Distributed under the terms of the GNU General Public License v2
+
+EAPI=8
+
+inherit libtool multilib-minimal preserve-libs usr-ldscript
+
+DESCRIPTION="Perl-compatible regular expression library"
+HOMEPAGE="http://www.pcre.org/"
+MY_P="pcre-${PV/_rc/-RC}"
+if [[ ${PV} != *_rc* ]] ; then
+	# Only the final releases are available here.
+	SRC_URI="
+		mirror://sourceforge/pcre/${MY_P}.tar.bz2
+		https://ftp.pcre.org/pub/pcre/${MY_P}.tar.bz2
+		ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/${MY_P}.tar.bz2
+	"
+else
+	SRC_URI="ftp://ftp.csx.cam.ac.uk/pub/software/programming/pcre/Testing/${MY_P}.tar.bz2"
+fi
+
+S="${WORKDIR}/${MY_P}"
+
+LICENSE="BSD"
+SLOT="3"
+KEYWORDS="~alpha ~amd64 ~arm ~arm64 ~hppa ~ia64 ~loong ~m68k ~mips ~ppc ~ppc64 ~riscv ~s390 ~sparc ~x86 ~amd64-linux ~x86-linux ~ppc-macos ~x64-macos ~x64-solaris"
+IUSE="bzip2 +cxx +jit libedit pcre16 pcre32 +readline static-libs unicode valgrind zlib"
+REQUIRED_USE="
+	readline? ( !libedit )
+	libedit? ( !readline )
+"
+
+RDEPEND="
+	bzip2? ( app-arch/bzip2 )
+	zlib? ( sys-libs/zlib )
+	libedit? ( dev-libs/libedit )
+	readline? ( sys-libs/readline:= )
+"
+DEPEND="
+	${RDEPEND}
+	valgrind? ( dev-util/valgrind )
+"
+BDEPEND="virtual/pkgconfig"
+
+MULTILIB_CHOST_TOOLS=(
+	/usr/bin/pcre-config
+)
+
+PATCHES=(
+	"${FILESDIR}"/${PN}-8.45-fix-stack-size-detection.patch
+)
+
+src_prepare() {
+	default
+
+	sed -i -e "s:-lpcre ::" libpcrecpp.pc.in || die
+	elibtoolize
+}
+
+multilib_src_configure() {
+	local myeconfargs=(
+		$(multilib_native_use_enable bzip2 pcregrep-libbz2)
+		$(use_enable cxx cpp)
+		$(use_enable jit)
+		$(use_enable jit pcregrep-jit)
+		$(use_enable pcre16)
+		$(use_enable pcre32)
+		$(multilib_native_use_enable libedit pcretest-libedit)
+		$(multilib_native_use_enable readline pcretest-libreadline)
+		$(use_enable static-libs static)
+		$(use_enable unicode utf)
+		$(use_enable unicode unicode-properties)
+		$(multilib_native_use_enable valgrind)
+		$(multilib_native_use_enable zlib pcregrep-libz)
+
+		--enable-pcre8
+		--enable-shared
+	)
+
+	ECONF_SOURCE="${S}" econf "${myeconfargs[@]}"
+}
+
+multilib_src_compile() {
+	emake V=1 $(multilib_is_native_abi || echo "bin_PROGRAMS=")
+}
+
+multilib_src_install() {
+	emake \
+		DESTDIR="${D}" \
+		$(multilib_is_native_abi || echo "bin_PROGRAMS= dist_html_DATA=") \
+		install
+
+	gen_usr_ldscript -a pcre
+}
+
+multilib_src_install_all() {
+	find "${ED}" -type f -name "*.la" -delete || die
+}
+
+pkg_preinst() {
+	preserve_old_lib /$(get_libdir)/libpcre.so.0
+}
+
+pkg_postinst() {
+	preserve_old_lib_notify /$(get_libdir)/libpcre.so.0
+}