From 54a35a5810b0475469b43d235f050cf8a8b7a54e Mon Sep 17 00:00:00 2001
From: Michał Górny <mgorny@gentoo.org>
Date: Sat, 10 Mar 2018 00:05:14 +0100
Subject: sys-libs/libcxx: Try building with -nodefaultlibs for bootstrap

Add a hack that appends -nodefaultlibs if the C++ compiler fails to link
software otherwise. This is based on what we do in sys-libs/compiler-rt
already and it should make it possible to bootstrap libc++ on systems
without C++ standard library.
---
 sys-libs/libcxx/libcxx-6.0.0.ebuild    | 14 ++++++++++++++
 sys-libs/libcxx/libcxx-6.0.9999.ebuild | 14 ++++++++++++++
 sys-libs/libcxx/libcxx-9999.ebuild     | 14 ++++++++++++++
 3 files changed, 42 insertions(+)

(limited to 'sys-libs/libcxx')

diff --git a/sys-libs/libcxx/libcxx-6.0.0.ebuild b/sys-libs/libcxx/libcxx-6.0.0.ebuild
index 9c9b75e3d7f1..0948ab0c6825 100644
--- a/sys-libs/libcxx/libcxx-6.0.0.ebuild
+++ b/sys-libs/libcxx/libcxx-6.0.0.ebuild
@@ -73,6 +73,11 @@ pkg_setup() {
 	fi
 }
 
+test_compiler() {
+	$(tc-getCXX) ${CXXFLAGS} ${LDFLAGS} "${@}" -o /dev/null -x c++ - \
+		<<<'int main() { return 0; }' &>/dev/null
+}
+
 multilib_src_configure() {
 	local cxxabi cxxabi_incs
 	if use libcxxabi; then
@@ -109,6 +114,15 @@ multilib_src_configure() {
 		fi
 	fi
 
+	# bootstrap: cmake is unhappy if compiler can't link to stdlib
+	local nolib_flags=( -nodefaultlibs -lc )
+	if ! test_compiler; then
+		if test_compiler "${nolib_flags[@]}"; then
+			local -x LDFLAGS="${LDFLAGS} ${nolib_flags[*]}"
+			ewarn "${CXX} seems to lack runtime, trying with ${nolib_flags[*]}"
+		fi
+	fi
+
 	local libdir=$(get_libdir)
 	local mycmakeargs=(
 		-DLIBCXX_LIBDIR_SUFFIX=${libdir#lib}
diff --git a/sys-libs/libcxx/libcxx-6.0.9999.ebuild b/sys-libs/libcxx/libcxx-6.0.9999.ebuild
index cf76bba5fdfd..4e687c722c60 100644
--- a/sys-libs/libcxx/libcxx-6.0.9999.ebuild
+++ b/sys-libs/libcxx/libcxx-6.0.9999.ebuild
@@ -85,6 +85,11 @@ pkg_setup() {
 	fi
 }
 
+test_compiler() {
+	$(tc-getCXX) ${CXXFLAGS} ${LDFLAGS} "${@}" -o /dev/null -x c++ - \
+		<<<'int main() { return 0; }' &>/dev/null
+}
+
 multilib_src_configure() {
 	local cxxabi cxxabi_incs
 	if use libcxxabi; then
@@ -121,6 +126,15 @@ multilib_src_configure() {
 		fi
 	fi
 
+	# bootstrap: cmake is unhappy if compiler can't link to stdlib
+	local nolib_flags=( -nodefaultlibs -lc )
+	if ! test_compiler; then
+		if test_compiler "${nolib_flags[@]}"; then
+			local -x LDFLAGS="${LDFLAGS} ${nolib_flags[*]}"
+			ewarn "${CXX} seems to lack runtime, trying with ${nolib_flags[*]}"
+		fi
+	fi
+
 	local libdir=$(get_libdir)
 	local mycmakeargs=(
 		-DLIBCXX_LIBDIR_SUFFIX=${libdir#lib}
diff --git a/sys-libs/libcxx/libcxx-9999.ebuild b/sys-libs/libcxx/libcxx-9999.ebuild
index 214c61d31f67..f304a076c171 100644
--- a/sys-libs/libcxx/libcxx-9999.ebuild
+++ b/sys-libs/libcxx/libcxx-9999.ebuild
@@ -84,6 +84,11 @@ pkg_setup() {
 	fi
 }
 
+test_compiler() {
+	$(tc-getCXX) ${CXXFLAGS} ${LDFLAGS} "${@}" -o /dev/null -x c++ - \
+		<<<'int main() { return 0; }' &>/dev/null
+}
+
 multilib_src_configure() {
 	local cxxabi cxxabi_incs
 	if use libcxxabi; then
@@ -120,6 +125,15 @@ multilib_src_configure() {
 		fi
 	fi
 
+	# bootstrap: cmake is unhappy if compiler can't link to stdlib
+	local nolib_flags=( -nodefaultlibs -lc )
+	if ! test_compiler; then
+		if test_compiler "${nolib_flags[@]}"; then
+			local -x LDFLAGS="${LDFLAGS} ${nolib_flags[*]}"
+			ewarn "${CXX} seems to lack runtime, trying with ${nolib_flags[*]}"
+		fi
+	fi
+
 	local libdir=$(get_libdir)
 	local mycmakeargs=(
 		-DLIBCXX_LIBDIR_SUFFIX=${libdir#lib}
-- 
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