[PATCH v2 2/8] perf python: split Clang options when invoking Popen

Leo Yan
2025-09-30T16:55:20Z

When passing a list to subprocess.Popen, each element maps to one argv
token. Current code bundles multiple Clang flags into a single element,
something like:

cmd = ['clang',
'--target=x86_64-linux-gnu -fintegrated-as -Wno-cast-function-type-mismatch',
'test-hello.c']

So Clang only sees one long, invalid option instead of separate flags,
as a result, the script cannot capture any log via PIPE.

Fix this by using shlex.split() to separate the string so each option
becomes its own argv element. The fixed list will be:

cmd = ['clang',
'--target=x86_64-linux-gnu',
'-fintegrated-as',
'-Wno-cast-function-type-mismatch',
'test-hello.c']

Fixes: 09e6f9f98370 ("perf python: Fix splitting CC into compiler and options")
Signed-off-by: Leo Yan <leo.yan@arm.com>
---
tools/perf/util/setup.py | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/tools/perf/util/setup.py b/tools/perf/util/setup.py
index dd289d15acfd62ff058bbaed7e565bb958e3a3c8..9cae2c472f4ad4d9579e8528b8bb0152df6fe20e 100644
--- a/tools/perf/util/setup.py
+++ b/tools/perf/util/setup.py
@@ -1,6 +1,7 @@
from os import getenv, path
from subprocess import Popen, PIPE
from re import sub
+import shlex

cc = getenv("CC")
assert cc, "Environment variable CC not set"
@@ -22,7 +23,9 @@ assert srctree, "Environment variable srctree, for the Linux sources, not set"
src_feature_tests = f'{srctree}/tools/build/feature'

def clang_has_option(option):
- cc_output = Popen([cc, cc_options + option, path.join(src_feature_tests, "test-hello.c") ], stderr=PIPE).stderr.readlines()
+ cmd = shlex.split(f"{cc} {cc_options} {option}")
+ cmd.append(path.join(src_feature_tests, "test-hello.c"))
+ cc_output = Popen(cmd, stderr=PIPE).stderr.readlines()
return [o for o in cc_output if ((b"unknown argument" in o) or (b"is not supported" in o) or (b"unknown warning option" in o))] == [ ]

if cc_is_clang:

--
2.34.1