[PAHOLE v4 3/3] tests: Support GCC in pfunct-btf-decl-tags test

GCC 16+ supports btf_decl_tag via DW_TAG_GNU_annotation. Update the
test to run with both GCC (>= 16) and clang when available, instead
of requiring clang only.

Signed-off-by: Vineet Gupta <[email protected]>
---
 tests/pfunct-btf-decl-tags.sh | 72 +++++++++++++++++++++++++++--------
 1 file changed, 56 insertions(+), 16 deletions(-)

diff --git a/tests/pfunct-btf-decl-tags.sh b/tests/pfunct-btf-decl-tags.sh
index 35884b4e8687..a46aa1f3df55 100755
--- a/tests/pfunct-btf-decl-tags.sh
+++ b/tests/pfunct-btf-decl-tags.sh
@@ -6,24 +6,36 @@
 source test_lib.sh
 
 outdir=$(make_tmpdir)
-tmpobj=$(make_tmpobj)
 
 # Comment this out to save test data.
 trap cleanup EXIT
 
 title_log "Check that pfunct can print btf_decl_tags read from BTF."
 
-# gcc now also supports decl tags as of gcc commit 43dcea48b8c,
-# in upstream version 16.
-# UPTODO: add a check here for that.
+# gcc 16+ supports decl tags via DW_TAG_GNU_annotation (gcc commit ac7027f180b).
 
+GCC=${GCC:-gcc}
 CLANG=${CLANG:-clang}
-if ! command -v $CLANG > /dev/null; then
-	error_log "Need clang for test $0"
+
+use_gcc=0
+if command -v $GCC > /dev/null; then
+	gcc_ver=$($GCC -dumpversion 2>/dev/null | cut -d. -f1)
+	if [ "$gcc_ver" -ge 16 ] 2>/dev/null; then
+		use_gcc=1
+	fi
+fi
+
+use_clang=0
+if command -v $CLANG > /dev/null; then
+	use_clang=1
+fi
+
+if [ "$use_gcc" -eq 0 ] && [ "$use_clang" -eq 0 ]; then
+	error_log "Need gcc >= 16 or clang for test $0"
 	test_fail
 fi
 
-(cat <<EOF
+src=$(cat <<EOF
 #define __tag(x) __attribute__((btf_decl_tag(#x)))
 
 __tag(a) __tag(b) __tag(c) void foo(void) {}
@@ -31,7 +43,7 @@ __tag(a) __tag(b)          void bar(void) {}
 __tag(a)                   void buz(void) {}
 
 EOF
-) | $CLANG --target=bpf -c -g -x c -o $tmpobj -
+)
 
 # tags order is not guaranteed
 sort_tags=$(cat <<EOF
@@ -54,16 +66,44 @@ a void buz(void);
 EOF
 )
 
-out=$(pfunct -P -F btf $tmpobj | awk "$sort_tags" | sort)
-d=$(diff -u <(echo "$expected") <(echo "$out"))
+run_test() {
+	local compiler=$1
+	local tmpobj=$2
+
+	info_log "Testing with $compiler"
+	out=$(pfunct -P -F btf $tmpobj | awk "$sort_tags" | sort)
+	d=$(diff -u <(echo "$expected") <(echo "$out"))
+
+	if [[ "$d" == "" ]]; then
+		info_log "  passed"
+		return 0
+	else
+		error_log "pfunct output does not match expected ($compiler):"
+		info_log "$d"
+		info_log
+		info_log "Complete output:"
+		info_log "$out"
+		return 1
+	fi
+}
+
+failed=0
+
+if [ "$use_gcc" -eq 1 ]; then
+	tmpobj=$(make_tmpobj)
+	echo "$src" | $GCC -c -g -x c -o $tmpobj - 2>/dev/null
+	pahole -J $tmpobj 2>/dev/null
+	run_test "$GCC (version $gcc_ver)" "$tmpobj" || failed=1
+fi
+
+if [ "$use_clang" -eq 1 ]; then
+	tmpobj=$(make_tmpobj)
+	echo "$src" | $CLANG --target=bpf -c -g -x c -o $tmpobj -
+	run_test "$CLANG" "$tmpobj" || failed=1
+fi
 
-if [[ "$d" == "" ]]; then
+if [ "$failed" -eq 0 ]; then
 	test_pass
 else
-	error_log "pfunct output does not match expected:"
-	info_log "$d"
-	info_log
-	info_log "Complete output:"
-	info_log "$out"
 	test_fail
 fi
-- 
2.54.0