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Date: Mon, 11 Mar 2024 11:43:54 -0400
From: "Michael S. Tsirkin" <mst@redhat.com>
To: Ian Rogers <irogers@google.com>
Cc: Arnd Bergmann <arnd@arndb.de>, Andrii Nakryiko <andrii@kernel.org>,
	Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
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	Yonghong Song <yonghong.song@linux.dev>,
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	Hao Luo <haoluo@google.com>, Jiri Olsa <jolsa@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Arnaldo Carvalho de Melo <acme@kernel.org>,
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	Alexander Shishkin <alexander.shishkin@linux.intel.com>,
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	Paolo Bonzini <pbonzini@redhat.com>, Shuah Khan <shuah@kernel.org>,
	Kees Cook <keescook@chromium.org>,
	"Gustavo A. R. Silva" <gustavoars@kernel.org>,
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	Nick Desaulniers <ndesaulniers@google.com>,
	Bill Wendling <morbo@google.com>,
	Justin Stitt <justinstitt@google.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Liam Howlett <liam.howlett@oracle.com>,
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	Nick Forrington <nick.forrington@arm.com>,
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	Sean Christopherson <seanjc@google.com>,
	Anup Patel <anup@brainfault.org>, Fuad Tabba <tabba@google.com>,
	Andrew Jones <ajones@ventanamicro.com>,
	Chao Peng <chao.p.peng@linux.intel.com>,
	Haibo Xu <haibo1.xu@intel.com>, Peter Xu <peterx@redhat.com>,
	Vishal Annapurve <vannapurve@google.com>,
	linux-kernel@vger.kernel.org, linux-arch@vger.kernel.org,
	bpf@vger.kernel.org, linux-perf-users@vger.kernel.org,
	kvm@vger.kernel.org, linux-kselftest@vger.kernel.org,
	linux-hardening@vger.kernel.org, llvm@lists.linux.dev,
	Christopher Di Bella <cjdb@google.com>
Subject: Re: [PATCH v1 13/13] tools headers: Rename noinline to __noinline
Message-ID: <20240311114009-mutt-send-email-mst@kernel.org>
References: <20240310020509.647319-1-irogers@google.com>
 <20240310020509.647319-14-irogers@google.com>
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In-Reply-To: <20240310020509.647319-14-irogers@google.com>

On Sat, Mar 09, 2024 at 06:05:08PM -0800, Ian Rogers wrote:
> An issue was reported with clang and llvm libc where the noinline
> attribute [1] was being expanded due to the #define in
> linux/compiler.h (now in compiler_attributes.h). The expansion caused
> the __attribute__ to appear twice and break the build. To avoid this
> conflict, rename noinline to __noinline which is more consistent with
> other compiler attributes.
> 
> [1] https://clang.llvm.org/docs/AttributeReference.html#noinline

Following this link, I don't see __noinline there - only __noinline__ and
noinline. What's up?


Als, pls add an empty line before tags.

> Reported-by: Christopher Di Bella <cjdb@google.com>
> 
> Signed-off-by: Ian Rogers <irogers@google.com>


tags should not have empty lines between them.

> ---
>  tools/include/linux/compiler_attributes.h |  4 ++--
>  tools/perf/arch/x86/tests/bp-modify.c     |  4 ++--
>  tools/perf/bench/find-bit-bench.c         |  2 +-
>  tools/perf/tests/bp_account.c             |  2 +-
>  tools/perf/tests/bp_signal.c              |  2 +-
>  tools/perf/tests/bp_signal_overflow.c     |  2 +-
>  tools/perf/tests/dwarf-unwind.c           | 12 ++++++------
>  tools/perf/tests/workloads/leafloop.c     |  8 ++++----
>  tools/perf/tests/workloads/thloop.c       |  4 ++--
>  9 files changed, 20 insertions(+), 20 deletions(-)
> 
> diff --git a/tools/include/linux/compiler_attributes.h b/tools/include/linux/compiler_attributes.h
> index 9bfaec783e48..1ff3d85f5af3 100644
> --- a/tools/include/linux/compiler_attributes.h
> +++ b/tools/include/linux/compiler_attributes.h
> @@ -267,12 +267,12 @@
>  # define __flatten			__attribute__((flatten))
>  
>  /*
> - * Note the missing underscores.
> + * Note, the kernel version is missing the underscores.
>   *
>   *   gcc: https://gcc.gnu.org/onlinedocs/gcc/Common-Function-Attributes.html#index-noinline-function-attribute
>   * clang: mentioned
>   */
> -#define   noinline                      __attribute__((__noinline__))
> +#define   __noinline                      __attribute__((__noinline__))
>  
>  /*
>   * Optional: only supported since gcc >= 8
> diff --git a/tools/perf/arch/x86/tests/bp-modify.c b/tools/perf/arch/x86/tests/bp-modify.c
> index 0924ccd9e36d..65493ff7a76f 100644
> --- a/tools/perf/arch/x86/tests/bp-modify.c
> +++ b/tools/perf/arch/x86/tests/bp-modify.c
> @@ -15,13 +15,13 @@
>  #include "tests/tests.h"
>  #include "arch-tests.h"
>  
> -static noinline int bp_1(void)
> +static __noinline int bp_1(void)
>  {
>  	pr_debug("in %s\n", __func__);
>  	return 0;
>  }
>  
> -static noinline int bp_2(void)
> +static __noinline int bp_2(void)
>  {
>  	pr_debug("in %s\n", __func__);
>  	return 0;
> diff --git a/tools/perf/bench/find-bit-bench.c b/tools/perf/bench/find-bit-bench.c
> index 7e25b0e413f6..dd97a51649bc 100644
> --- a/tools/perf/bench/find-bit-bench.c
> +++ b/tools/perf/bench/find-bit-bench.c
> @@ -31,7 +31,7 @@ static const char *const bench_usage[] = {
>  static unsigned int accumulator;
>  static unsigned int use_of_val;
>  
> -static noinline void workload(int val)
> +static __noinline void workload(int val)
>  {
>  	use_of_val += val;
>  	accumulator++;
> diff --git a/tools/perf/tests/bp_account.c b/tools/perf/tests/bp_account.c
> index 6f921db33cf9..459f61752a71 100644
> --- a/tools/perf/tests/bp_account.c
> +++ b/tools/perf/tests/bp_account.c
> @@ -34,7 +34,7 @@
>  
>  static volatile long the_var;
>  
> -static noinline int test_function(void)
> +static __noinline int test_function(void)
>  {
>  	return 0;
>  }
> diff --git a/tools/perf/tests/bp_signal.c b/tools/perf/tests/bp_signal.c
> index 1f2908f02389..484a7e7f96ee 100644
> --- a/tools/perf/tests/bp_signal.c
> +++ b/tools/perf/tests/bp_signal.c
> @@ -59,7 +59,7 @@ static void __test_function(volatile long *ptr)
>  }
>  #endif
>  
> -static noinline int test_function(void)
> +static __noinline int test_function(void)
>  {
>  	__test_function(&the_var);
>  	the_var++;
> diff --git a/tools/perf/tests/bp_signal_overflow.c b/tools/perf/tests/bp_signal_overflow.c
> index 4e897c2cf26b..9436bf2973f8 100644
> --- a/tools/perf/tests/bp_signal_overflow.c
> +++ b/tools/perf/tests/bp_signal_overflow.c
> @@ -30,7 +30,7 @@
>  
>  static int overflows;
>  
> -static noinline int test_function(void)
> +static __noinline int test_function(void)
>  {
>  	return time(NULL);
>  }
> diff --git a/tools/perf/tests/dwarf-unwind.c b/tools/perf/tests/dwarf-unwind.c
> index d01aa931fe81..a669c69a9242 100644
> --- a/tools/perf/tests/dwarf-unwind.c
> +++ b/tools/perf/tests/dwarf-unwind.c
> @@ -109,7 +109,7 @@ static int unwind_entry(struct unwind_entry *entry, void *arg)
>  	return strcmp((const char *) symbol, funcs[idx]);
>  }
>  
> -NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__thread(struct thread *thread)
> +NO_TAIL_CALL_ATTRIBUTE __noinline int test_dwarf_unwind__thread(struct thread *thread)
>  {
>  	struct perf_sample sample;
>  	unsigned long cnt = 0;
> @@ -140,7 +140,7 @@ NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__thread(struct thread *thr
>  
>  static int global_unwind_retval = -INT_MAX;
>  
> -NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__compare(void *p1, void *p2)
> +NO_TAIL_CALL_ATTRIBUTE __noinline int test_dwarf_unwind__compare(void *p1, void *p2)
>  {
>  	/* Any possible value should be 'thread' */
>  	struct thread *thread = *(struct thread **)p1;
> @@ -159,7 +159,7 @@ NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__compare(void *p1, void *p
>  	return p1 - p2;
>  }
>  
> -NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__krava_3(struct thread *thread)
> +NO_TAIL_CALL_ATTRIBUTE __noinline int test_dwarf_unwind__krava_3(struct thread *thread)
>  {
>  	struct thread *array[2] = {thread, thread};
>  	void *fp = &bsearch;
> @@ -178,7 +178,7 @@ NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__krava_3(struct thread *th
>  	return global_unwind_retval;
>  }
>  
> -NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__krava_2(struct thread *thread)
> +NO_TAIL_CALL_ATTRIBUTE __noinline int test_dwarf_unwind__krava_2(struct thread *thread)
>  {
>  	int ret;
>  
> @@ -187,7 +187,7 @@ NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__krava_2(struct thread *th
>  	return ret;
>  }
>  
> -NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__krava_1(struct thread *thread)
> +NO_TAIL_CALL_ATTRIBUTE __noinline int test_dwarf_unwind__krava_1(struct thread *thread)
>  {
>  	int ret;
>  
> @@ -196,7 +196,7 @@ NO_TAIL_CALL_ATTRIBUTE noinline int test_dwarf_unwind__krava_1(struct thread *th
>  	return ret;
>  }
>  
> -noinline int test__dwarf_unwind(struct test_suite *test __maybe_unused,
> +__noinline int test__dwarf_unwind(struct test_suite *test __maybe_unused,
>  				int subtest __maybe_unused)
>  {
>  	struct machine *machine;
> diff --git a/tools/perf/tests/workloads/leafloop.c b/tools/perf/tests/workloads/leafloop.c
> index 1bf5cc97649b..89d2cec2f461 100644
> --- a/tools/perf/tests/workloads/leafloop.c
> +++ b/tools/perf/tests/workloads/leafloop.c
> @@ -4,18 +4,18 @@
>  #include "../tests.h"
>  
>  /* We want to check these symbols in perf script */
> -noinline void leaf(volatile int b);
> -noinline void parent(volatile int b);
> +__noinline void leaf(volatile int b);
> +__noinline void parent(volatile int b);
>  
>  static volatile int a;
>  
> -noinline void leaf(volatile int b)
> +__noinline void leaf(volatile int b)
>  {
>  	for (;;)
>  		a += b;
>  }
>  
> -noinline void parent(volatile int b)
> +__noinline void parent(volatile int b)
>  {
>  	leaf(b);
>  }
> diff --git a/tools/perf/tests/workloads/thloop.c b/tools/perf/tests/workloads/thloop.c
> index 457b29f91c3e..e252efb76203 100644
> --- a/tools/perf/tests/workloads/thloop.c
> +++ b/tools/perf/tests/workloads/thloop.c
> @@ -9,14 +9,14 @@
>  static volatile sig_atomic_t done;
>  
>  /* We want to check this symbol in perf report */
> -noinline void test_loop(void);
> +__noinline void test_loop(void);
>  
>  static void sighandler(int sig __maybe_unused)
>  {
>  	done = 1;
>  }
>  
> -noinline void test_loop(void)
> +__noinline void test_loop(void)
>  {
>  	while (!done);
>  }
> -- 
> 2.44.0.278.ge034bb2e1d-goog