perf build: Support building with Clang #6043
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Upstream branch: d4680a1 |
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The feature test programs are built without enabling '-Wall -Werror' options. As a result, a feature may appear to be available, but later building in perf can fail with stricter checks. Make the feature test program use the same warning options as perf. Fixes: 1925459 ("tools build: Fix feature Makefile issues with 'O='") Signed-off-by: Leo Yan <[email protected]>
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: 09e6f9f ("perf python: Fix splitting CC into compiler and options")
Signed-off-by: Leo Yan <[email protected]>
clang-18.1.3 on Ubuntu 24.04.2 reports warning: warning: unknown warning option '-Wformat-signedness' [-Wunknown-warning-option] Conditionally add the option only when it is supported by compiler. Signed-off-by: Leo Yan <[email protected]>
clang-18.1.3 on Ubuntu 24.04.2 reports warning:
memcpy_thread.c:30:1: warning: non-void function does not return a value in all control paths [-Wreturn-type]
30 | }
| ^
Dismiss the warning with returning NULL from the thread function.
Signed-off-by: Leo Yan <[email protected]>
clang-18.1.3 on Ubuntu 24.04.2 reports warning:
thread_loop.c:41:23: warning: value size does not match register size specified by the constraint and modifier [-Wasm-operand-widths]
41 | : /* in */ [i] "r" (i), [len] "r" (len)
| ^
thread_loop.c:37:8: note: use constraint modifier "w"
37 | "add %[i], %[i], #1\n"
| ^~~~
| %w[i]
thread_loop.c:41:23: warning: value size does not match register size specified by the constraint and modifier [-Wasm-operand-widths]
41 | : /* in */ [i] "r" (i), [len] "r" (len)
| ^
thread_loop.c:37:14: note: use constraint modifier "w"
37 | "add %[i], %[i], #1\n"
| ^~~~
| %w[i]
thread_loop.c:41:23: warning: value size does not match register size specified by the constraint and modifier [-Wasm-operand-widths]
41 | : /* in */ [i] "r" (i), [len] "r" (len)
| ^
thread_loop.c:38:8: note: use constraint modifier "w"
38 | "cmp %[i], %[len]\n"
| ^~~~
| %w[i]
thread_loop.c:41:38: warning: value size does not match register size specified by the constraint and modifier [-Wasm-operand-widths]
41 | : /* in */ [i] "r" (i), [len] "r" (len)
| ^
thread_loop.c:38:14: note: use constraint modifier "w"
38 | "cmp %[i], %[len]\n"
| ^~~~~~
| %w[len]
Use the modifier "w" for 32-bit register access.
Signed-off-by: Leo Yan <[email protected]>
clang-18.1.3 on Ubuntu 24.04.2 reports warning:
unroll_loop_thread.c:35:25: warning: value size does not match register size specified by the constraint and modifier [-Wasm-operand-widths]
35 | : /* in */ [in] "r" (in)
| ^
unroll_loop_thread.c:39:1: warning: non-void function does not return a value [-Wreturn-type]
39 | }
| ^
Use the modifier "w" for 32-bit register access and return NULL at the
end of thread function.
Signed-off-by: Leo Yan <[email protected]>
Add support for building perf with clang. For cross compilation, the
Makefile dynamically selects target flag for corresponding arch.
This patch has been verified on x86_64 machine with Ubuntu distro, it
can build successfully for native target, and for cross building Arm64
and s390.
Example: native build on x86_64 / Ubuntu machine:
$ HOSTCC=clang CC=clang CXX=clang++ make -C tools/perf
Example: cross building s390 target on x86_64 / Ubuntu machine:
# Install x390x cross toolchain and headers
$ sudo apt-get install gcc-s390x-linux-gnu g++-s390x-linux-gnu \
libc6-dev-s390x-cross linux-libc-dev-s390x-cross
# Build with clang
$ HOSTCC=clang CC=clang CXX=clang++ \
ARCH=s390 CROSS_COMPILE=s390x-linux-gnu- \
make -C tools/perf NO_LIBELF=1 NO_LIBTRACEEVENT=1 NO_LIBPYTHON=1
Signed-off-by: Leo Yan <[email protected]>
Author
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Upstream branch: dd948aa |
Add example commands for building perf with Clang. Since recent Android NDK releases use Clang as the default compiler, a separate Android specific document is no longer needed; point to the general build documentation instead. Signed-off-by: Leo Yan <[email protected]>
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At least one diff in series https://patchwork.kernel.org/project/netdevbpf/list/?series=1006111 irrelevant now. Closing PR. |
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Pull request for series with
subject: perf build: Support building with Clang
version: 1
url: https://patchwork.kernel.org/project/netdevbpf/list/?series=1006111