flag-o-matic.eclass: revert "don't use -Werror in test-flag-PROG(), bug #712488"

This reverts commit ab8fe14ae2e9110faa85ca1c4528b470c0be1535.
Triggers build failures on sys-libs/compiler-rt-sanitizers.

Reported-by: Craig Andrews
Bug: https://bugs.gentoo.org/714742
Bug: https://bugs.gentoo.org/712488
Signed-off-by: Sergei Trofimovich <slyfox@gentoo.org>

diff --git a/eclass/flag-o-matic.eclass b/eclass/flag-o-matic.eclass
index d8111fb9e38f4c07b009ca1a60c23656a84b7c43..9ef9ac3685e00f48268e71f40812b42c72fd8faf 100644 (file)
--- a/eclass/flag-o-matic.eclass
+++ b/eclass/flag-o-matic.eclass
@@ -487,15 +487,11 @@ test-flag-PROG() {
 
        printf "%s\n" "${in_src}" > "${test_in}" || die "Failed to create '${test_in}'"
 
-       # Don't set -Werror as there are cases when benign
-       # always-on warnings filter out all flags like bug #712488.
-       # We'll have to live with potential '-Wunused-command-line-argument'.
-       # flags.
-       #
-       # We can add more selective detection of no-op flags via
-       # '-Werror=ignored-optimization-argument' and similar error options.
        local cmdline=(
                "${comp[@]}"
+               # Clang will warn about unknown gcc flags but exit 0.
+               # Need -Werror to force it to exit non-zero.
+               -Werror
                "$@"
                # -x<lang> options need to go before first source file
                "${cmdline_extra[@]}"
@@ -503,7 +499,14 @@ test-flag-PROG() {
                "${test_in}" -o "${test_out}"
        )
 
-       "${cmdline[@]}" &>/dev/null
+       if ! "${cmdline[@]}" &>/dev/null; then
+               # -Werror makes clang bail out on unused arguments as well;
+               # try to add -Qunused-arguments to work-around that
+               # other compilers don't support it but then, it's failure like
+               # any other
+               cmdline+=( -Qunused-arguments )
+               "${cmdline[@]}" &>/dev/null
+       fi
 }
 
 # @FUNCTION: test-flag-CC

diff --git a/eclass/tests/flag-o-matic.sh b/eclass/tests/flag-o-matic.sh
index 6dfacb04c07777d80982ae83244a8b9e19023ba4..229dff52af945d6c4f7fc0b83571cf7b98067657 100755 (executable)
--- a/eclass/tests/flag-o-matic.sh
+++ b/eclass/tests/flag-o-matic.sh
@@ -161,12 +161,10 @@ out=$(CC=clang test-flags-CC -finvalid-flag)
 [[ $? -ne 0 && -z ${out} ]]
 ftend
 
-### '-finline-limit=1200' is 'ignored' flag, not invalid.
-### We don't filter out ignored flags currently, bug #712488
-#tbegin "test-flags-CC (gcc-valid but clang-invalid flags)"
-#out=$(CC=clang test-flags-CC -finline-limit=1200)
-#[[ $? -ne 0 && -z ${out} ]]
-#ftend
+tbegin "test-flags-CC (gcc-valid but clang-invalid flags)"
+out=$(CC=clang test-flags-CC -finline-limit=1200)
+[[ $? -ne 0 && -z ${out} ]]
+ftend
 
 tbegin "test-flags-CC (unused flags w/clang)"
 out=$(CC=clang test-flags-CC -Wl,-O1)