Re: [PATCH v8 11/17] perf c2c: Use perf_env e_machine rather than arch

[sashiko-bot@kernel.org]

Thank you for your contribution! Sashiko AI review found 1 potential issue(s) to consider:
- [Low] Build failure on older toolchains due to missing fallback definition for `EM_AARCH64`.
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commit 5745fb586646dd63f1bc0598424b6a0b707af964
Author: Ian Rogers <irogers@google.com>

perf c2c: Use perf_env e_machine rather than arch
    
This commit updates perf c2c to use the e_machine value from the perf_env
environment instead of performing string matching on the architecture name
for AARCH64 detection.

> diff --git a/tools/perf/builtin-c2c.c b/tools/perf/builtin-c2c.c
> index 72a7802775ee..09c8352a922c 100644
> --- a/tools/perf/builtin-c2c.c
> +++ b/tools/perf/builtin-c2c.c
> @@ -3202,7 +3202,7 @@ static int perf_c2c__report(int argc, const char **argv)
>  	 * default display type.
>  	 */
>  	if (!display) {
> -		if (!strcmp(perf_env__arch(env), "arm64"))
> +		if (perf_env__e_machine(env, /*e_flags=*/NULL) == EM_AARCH64)

Will this cause a build failure on older toolchains where the system <elf.h>
does not yet define EM_AARCH64?

On older systems (for example, those with glibc earlier than 2.17),
EM_AARCH64 might not be declared. Other files in the perf codebase provide
a manual fallback definition for it, but builtin-c2c.c does not appear to
include one.

>  			display = "peer";
>  		else
>  			display = "tot";

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Sashiko AI review · https://sashiko.dev/#/patchset/20260502065935.291960-1-irogers@google.com?part=11