[dwarves,v1,2/2] tests: verify that pfunct prints btf_decl_tags read from BTF

Commit Message

Eduard Zingerman Dec. 11, 2024, 2:12 a.m. UTC

When using BTF as a source, pfunct should now be able to print
btf_decl_tags for programs like below:

  #define __tag(x) __attribute__((btf_decl_tag(#x)))
  __tag(a) __tag(b) void foo(void) {}

This situation arises after recent kernel changes, where tags 'kfunc'
and 'bpf_fastcall' are added to some functions. To avoid dependency on
a recent kernel version test this by compiling a small C program using
clang with --target=bpf, which would instruct clang to generate .BTF
section.

Signed-off-by: Eduard Zingerman <[e-mail]>
---
 tests/pfunct-btf-decl-tags.sh | 65 +++++++++++++++++++++++++++++++++++
 1 file changed, 65 insertions(+)
 create mode 100755 tests/pfunct-btf-decl-tags.sh

Patch

diff --git a/tests/pfunct-btf-decl-tags.sh b/tests/pfunct-btf-decl-tags.sh
new file mode 100755
index 0000000..7e7f547
--- /dev/null
+++ b/tests/pfunct-btf-decl-tags.sh
@@ -0,0 +1,65 @@ 
+#!/bin/bash
+# SPDX-License-Identifier: GPL-2.0-only
+
+# Check that pfunct can print btf_decl_tags read from BTF
+
+tmpobj=$(mktemp /tmp/pfunct-btf-decl-tags.sh.XXXXXX.o)
+
+cleanup()
+{
+	rm $tmpobj
+}
+
+trap cleanup EXIT
+
+CLANG=${CLANG:-clang}
+if ! command -v $CLANG > /dev/null; then
+	echo "Need clang for test $0"
+	exit 1
+fi
+
+(cat <<EOF
+#define __tag(x) __attribute__((btf_decl_tag(#x)))
+
+__tag(a) __tag(b) __tag(c) void foo(void) {}
+__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
+{
+match(\$0,/^(.*) (void .*)/,tags_and_proto);
+tags  = tags_and_proto[1];
+proto = tags_and_proto[2];
+split(tags, tags_arr ,/ /);
+asort(tags_arr);
+for (t in tags_arr) printf "%s ", tags_arr[t];
+print proto;
+}
+EOF
+)
+
+expected=$(cat <<EOF
+a b c void foo(void);
+a b void bar(void);
+a void buz(void);
+EOF
+)
+
+out=$(pfunct -P -F btf $tmpobj | awk "$sort_tags" | sort)
+d=$(diff -u <(echo "$expected") <(echo "$out"))
+
+if [[ "$d" == "" ]]; then
+	echo "Ok"
+	exit 0
+else
+	echo "pfunct output does not match expected:"
+	echo "$d"
+	echo
+	echo "Complete output:"
+	echo "$out"
+	exit 1
+fi