From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from 66-220-144-179.mail-mxout.facebook.com (66-220-144-179.mail-mxout.facebook.com [66.220.144.179]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 864E638F230 for ; Thu, 26 Mar 2026 01:33:25 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=66.220.144.179 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774488807; cv=none; b=ICGwxzYYFNpxA7AKllMytjjVcL7sYe312190gBepb7YvEtbSltPJtQlehuxquakYPMquuwV+pU6EBvPl1miQrPj2fG1jPgzaGv87vlau7H0KRRxWvmaSc7ebfYpiyRaEa0cgNoyb6XKgWIIxd8ScUPkDkPKAu24MCsQg4KNXKus= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1774488807; c=relaxed/simple; bh=J2RdMpQntrqEnFsNe7pSPauqh4spc0PHbz4CijK3BrU=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=uFhFWJx2MEGNCDS3ICjepBXOZHG6H2PRxTERVvhePA1GVcnPOFEoBcDhX4bEHdO5vW06Rwibj63bSLJtxan6aHIo4+6s59t2G65pfYMXP/aJO3KbgZvxzSBe4dJ4ApLcbMAY+y/LHZeVtuAeu/aN+Aemr9Id8kfUdJJmWc9WFr0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev; spf=fail smtp.mailfrom=linux.dev; arc=none smtp.client-ip=66.220.144.179 Authentication-Results: smtp.subspace.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.dev Authentication-Results: smtp.subspace.kernel.org; spf=fail smtp.mailfrom=linux.dev Received: by devvm16039.vll0.facebook.com (Postfix, from userid 128203) id 172C62E28119A; Wed, 25 Mar 2026 18:33:18 -0700 (PDT) From: Yonghong Song To: Alan Maguire , Arnaldo Carvalho de Melo , dwarves@vger.kernel.org Cc: Alexei Starovoitov , Andrii Nakryiko , bpf@vger.kernel.org, kernel-team@fb.com Subject: [PATCH dwarves v4 11/11] tests: Add a few clang true signature tests Date: Wed, 25 Mar 2026 18:33:18 -0700 Message-ID: <20260326013318.2912927-1-yonghong.song@linux.dev> X-Mailer: git-send-email 2.52.0 In-Reply-To: <20260326013144.2901265-1-yonghong.song@linux.dev> References: <20260326013144.2901265-1-yonghong.song@linux.dev> Precedence: bulk X-Mailing-List: dwarves@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Three tests are added. Test 1: VERBOSE=3D1 ./clang_parm_optimized.sh BTF: BTF: int foo(int a, int c); DWARF: DWARF: int foo(int a, int b, int c); where parameber 'b' is unused. Test 2: VERBOSE=3D1 ./clang_parm_optimized_stack.sh BTF: BTF: int foo(int a, int i); DWARF: DWARF: int foo(int a, int b, int c, int d, int e, int f, int g, = int h, int i); where parameters 'b' to 'h' are unused. Test 3: VERBOSE=3D1 ./clang_parm_aggregate.sh BTF (x86_64): long foo(long a__f1, struct t b, int i); BTF (aarch64): long foo(struct t a, struct t b, int i); DWARF: long foo(struct t a, struct t b, int i); where the 'struct t' definition is 'struct t { long f1; long f2; };', and a.f2 is not used in the function for x86_64 arch. Signed-off-by: Yonghong Song --- tests/clang_parm_aggregate.sh | 85 +++++++++++++++++++++++++++++ tests/clang_parm_optimized.sh | 63 +++++++++++++++++++++ tests/clang_parm_optimized_stack.sh | 63 +++++++++++++++++++++ 3 files changed, 211 insertions(+) create mode 100755 tests/clang_parm_aggregate.sh create mode 100755 tests/clang_parm_optimized.sh create mode 100755 tests/clang_parm_optimized_stack.sh diff --git a/tests/clang_parm_aggregate.sh b/tests/clang_parm_aggregate.s= h new file mode 100755 index 0000000..9502f8b --- /dev/null +++ b/tests/clang_parm_aggregate.sh @@ -0,0 +1,85 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0-only + +source test_lib.sh + +outdir=3D$(make_tmpdir) + +# Comment this out to save test data. +trap cleanup EXIT + +title_log "Validation of BTF encoding of true_signatures." + +clang_true=3D"${outdir}/clang_true" +CC=3D$(which clang 2>/dev/null) + +if [[ -z "$CC" ]]; then + info_log "skip: clang not available" + test_skip +fi + +cat > ${clang_true}.c << EOF +struct t { long f1; long f2; }; +__attribute__((noinline)) static long foo(struct t a, struct t b, int i) +{ + return a.f1 + b.f1 + b.f2 + i; +} + +struct t p1, p2; +int i; +int main() +{ + return (int)foo(p1, p2, i); +} +EOF + +CFLAGS=3D"$CFLAGS -g -O2" +${CC} ${CFLAGS} -o $clang_true ${clang_true}.c +if [[ $? -ne 0 ]]; then + error_log "Could not compile ${clang_true}.c" + test_fail +fi +LLVM_OBJCOPY=3Dobjcopy pahole -J --btf_features=3D+true_signature $clang= _true +if [[ $? -ne 0 ]]; then + error_log "Could not encode BTF for $clang_true" + test_fail +fi + +btf_optimized=3D$(pfunct --all --format_path=3Dbtf $clang_true |grep "fo= o") +if [[ -z "$btf_optimized" ]]; then + info_log "skip: no optimizations applied." + test_skip +fi + +btf_cmp=3D$btf_optimized +dwarf=3D$(pfunct --all $clang_true |grep "foo") + +verbose_log "BTF: $btf_optimized DWARF: $dwarf" + +arch=3D$(uname -m) + +if [[ "$arch" =3D=3D "x86_64" ]]; then + # On x86_64, clang emits DW_CC_nocall for optimized functions, + # so pahole should detect the optimization and produce a + # different BTF signature. + if [[ "$btf_cmp" =3D=3D "$dwarf" ]]; then + error_log "BTF and DWARF signatures should be different and they are n= ot: BTF: $btf_optimized ; DWARF $dwarf" + test_fail + fi +elif [[ "$arch" =3D=3D "aarch64" ]]; then + # On arm64, clang does not emit DW_CC_nocall, so pahole cannot + # detect the optimization. BTF and DWARF signatures are expected + # to be the same. + if [[ "$btf_cmp" !=3D "$dwarf" ]]; then + error_log "On arm64, BTF and DWARF signatures should be the same but t= hey are not: BTF: $btf_optimized ; DWARF $dwarf" + test_fail + fi +else + # On other architectures, skip if we cannot determine the + # expected behavior. + if [[ "$btf_cmp" =3D=3D "$dwarf" ]]; then + info_log "skip: no optimization detected on $arch" + test_skip + fi +fi +test_pass diff --git a/tests/clang_parm_optimized.sh b/tests/clang_parm_optimized.s= h new file mode 100755 index 0000000..81d50af --- /dev/null +++ b/tests/clang_parm_optimized.sh @@ -0,0 +1,63 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0-only + +source test_lib.sh + +outdir=3D$(make_tmpdir) + +# Comment this out to save test data. +trap cleanup EXIT + +title_log "Validation of BTF encoding of true_signatures." + +clang_true=3D"${outdir}/clang_true" +CC=3D$(which clang 2>/dev/null) + +if [[ -z "$CC" ]]; then + info_log "skip: clang not available" + test_skip +fi + +cat > ${clang_true}.c << EOF +__attribute__((noinline)) static int foo(int a, int b, int c) +{ + return a * c - a - c; +} + +int a, b, c; +int main() +{ + return foo(a, b, c); +} +EOF + +CFLAGS=3D"$CFLAGS -g -O2" +${CC} ${CFLAGS} -o $clang_true ${clang_true}.c +if [[ $? -ne 0 ]]; then + error_log "Could not compile ${clang_true}.c" + test_fail +fi +LLVM_OBJCOPY=3Dobjcopy pahole -J --btf_features=3D+true_signature $clang= _true +if [[ $? -ne 0 ]]; then + error_log "Could not encode BTF for $clang_true" + test_fail +fi + +btf_optimized=3D$(pfunct --all --format_path=3Dbtf $clang_true |grep "fo= o") +if [[ -z "$btf_optimized" ]]; then + info_log "skip: no optimizations applied." + test_skip +fi + +btf_cmp=3D$btf_optimized +dwarf=3D$(pfunct --all $clang_true |grep "foo") + +if [[ -n "$VERBOSE" ]]; then + printf " BTF: %s DWARF: %s\n" "$btf_optimized" "$dwarf" +fi + +if [[ "$btf_cmp" =3D=3D "$dwarf" ]]; then + error_log "BTF and DWARF signatures should be different and they are no= t: BTF: $btf_optimized ; DWARF $dwarf" + test_fail +fi +test_pass diff --git a/tests/clang_parm_optimized_stack.sh b/tests/clang_parm_optim= ized_stack.sh new file mode 100755 index 0000000..afdc355 --- /dev/null +++ b/tests/clang_parm_optimized_stack.sh @@ -0,0 +1,63 @@ +#!/bin/bash +# SPDX-License-Identifier: GPL-2.0-only + +source test_lib.sh + +outdir=3D$(make_tmpdir) + +# Comment this out to save test data. +trap cleanup EXIT + +title_log "Validation of BTF encoding of true_signatures." + +clang_true=3D"${outdir}/clang_true" +CC=3D$(which clang 2>/dev/null) + +if [[ -z "$CC" ]]; then + info_log "skip: clang not available" + test_skip +fi + +cat > ${clang_true}.c << EOF +__attribute__((noinline)) static int foo(int a, int b, int c, int d, int= e, int f, int g, int h, int i) +{ + return a * i - a - i; +} + +int a, b, c, d, e, f, g, h, i; +int main() +{ + return foo(a, b, c, d, e, f, g, h, i); +} +EOF + +CFLAGS=3D"$CFLAGS -g -O2" +${CC} ${CFLAGS} -o $clang_true ${clang_true}.c +if [[ $? -ne 0 ]]; then + error_log "Could not compile ${clang_true}.c" + test_fail +fi +LLVM_OBJCOPY=3Dobjcopy pahole -J --btf_features=3D+true_signature $clang= _true +if [[ $? -ne 0 ]]; then + error_log "Could not encode BTF for $clang_true" + test_fail +fi + +btf_optimized=3D$(pfunct --all --format_path=3Dbtf $clang_true |grep "fo= o") +if [[ -z "$btf_optimized" ]]; then + info_log "skip: no optimizations applied." + test_skip +fi + +btf_cmp=3D$btf_optimized +dwarf=3D$(pfunct --all $clang_true |grep "foo") + +if [[ -n "$VERBOSE" ]]; then + printf " BTF: %s DWARF: %s\n" "$btf_optimized" "$dwarf" +fi + +if [[ "$btf_cmp" =3D=3D "$dwarf" ]]; then + error_log "BTF and DWARF signatures should be different and they are no= t: BTF: $btf_optimized ; DWARF $dwarf" + test_fail +fi +test_pass --=20 2.52.0