diff --git a/sys-libs/llvm-libunwind/llvm-libunwind-6.0.0.ebuild b/sys-libs/llvm-libunwind/llvm-libunwind-6.0.0.ebuild
index 45ca2b2e5f9f1..db6bc3cacf891 100644
--- a/sys-libs/llvm-libunwind/llvm-libunwind-6.0.0.ebuild
+++ b/sys-libs/llvm-libunwind/llvm-libunwind-6.0.0.ebuild
@@ -25,10 +25,13 @@ RESTRICT="!test? ( test )"
 
 RDEPEND="!sys-libs/libunwind"
 # llvm-6 for new lit options
+# tests need libcxx with implicit -lunwind and libcxxabi
+# (but libcxx does not need to be built against it)
 DEPEND="
 	>=sys-devel/llvm-6
 	test? (
-		sys-libs/libcxx[${MULTILIB_USEDEP}]
+		sys-libs/libcxx[libunwind,${MULTILIB_USEDEP}]
+		sys-libs/libcxxabi
 		$(python_gen_any_dep 'dev-python/lit[${PYTHON_USEDEP}]') )"
 
 S=${WORKDIR}/${MY_P}
diff --git a/sys-libs/llvm-libunwind/llvm-libunwind-6.0.9999.ebuild b/sys-libs/llvm-libunwind/llvm-libunwind-6.0.9999.ebuild
index 789d9a6d71c73..6eb95d733fc2b 100644
--- a/sys-libs/llvm-libunwind/llvm-libunwind-6.0.9999.ebuild
+++ b/sys-libs/llvm-libunwind/llvm-libunwind-6.0.9999.ebuild
@@ -24,10 +24,13 @@ RESTRICT="!test? ( test )"
 
 RDEPEND="!sys-libs/libunwind"
 # llvm-6 for new lit options
+# tests need libcxx with implicit -lunwind and libcxxabi
+# (but libcxx does not need to be built against it)
 DEPEND="
 	>=sys-devel/llvm-6
 	test? (
-		sys-libs/libcxx[${MULTILIB_USEDEP}]
+		sys-libs/libcxx[libunwind,${MULTILIB_USEDEP}]
+		sys-libs/libcxxabi
 		$(python_gen_any_dep 'dev-python/lit[${PYTHON_USEDEP}]') )"
 
 # least intrusive of all
diff --git a/sys-libs/llvm-libunwind/llvm-libunwind-9999.ebuild b/sys-libs/llvm-libunwind/llvm-libunwind-9999.ebuild
index c16358fe4c623..387b8c31086c2 100644
--- a/sys-libs/llvm-libunwind/llvm-libunwind-9999.ebuild
+++ b/sys-libs/llvm-libunwind/llvm-libunwind-9999.ebuild
@@ -23,10 +23,13 @@ RESTRICT="!test? ( test )"
 
 RDEPEND="!sys-libs/libunwind"
 # llvm-6 for new lit options
+# tests need libcxx with implicit -lunwind and libcxxabi
+# (but libcxx does not need to be built against it)
 DEPEND="
 	>=sys-devel/llvm-6
 	test? (
-		sys-libs/libcxx[${MULTILIB_USEDEP}]
+		sys-libs/libcxx[libunwind,${MULTILIB_USEDEP}]
+		sys-libs/libcxxabi
 		$(python_gen_any_dep 'dev-python/lit[${PYTHON_USEDEP}]') )"
 
 # least intrusive of all