[llvm] [benchmark] Support Linux/sparc64 /proc/cpuinfo (PR #125503)

[Rainer Orth via llvm-commits]

https://github.com/rorth created https://github.com/llvm/llvm-project/pull/125503

When running an LLVM 20.1.0 rc1 reltest on Linux/sparc64, all 75 of the new `libcxx/test/benchmarks` tests `FAIL`, all in the same way:

```
# .---command stderr------------
# | Unable to extract number of CPUs.  If your platform uses /proc/cpuinfo, custom support may need to be added.
```

And indeed the Linux/sparc64 `/proc/cpuinfo` format is completely different from the x86_64 one: the interesting line is
```
ncpus active	: 24
```
This patch adjusts `sysinfo.cc` to handle that.

Tested on `sparc64-unknown-linux-gnu`.

I hope this can go in without going via upstream which doesn't have the analogous alpha patch either.

>From ff8c8395cef71103d9c8b1e6c3492892b274be9a Mon Sep 17 00:00:00 2001
From: Rainer Orth <ro at gcc.gnu.org>
Date: Mon, 3 Feb 2025 15:00:43 +0100
Subject: [PATCH] [benchmark] Support Linux/sparc64 /proc/cpuinfo

When running an LLVM 20.1.0 rc1 reltest on Linux/sparc64, all 75 of the new
`libcxx/test/benchmarks` tests `FAIL`, all in the same way:

```
```

And indeed the Linux/sparc64 /proc/cpuinfo format is completely different
from the x86_64 one: the interesting line is

ncpus active	: 24

This patch adjusts `sysinfo.cc` to handle that.

Tested on `sparc64-unknown-linux-gnu`.

I hope this can go in without going via upstream which doesn't have the
analogous alpha patch either.
---
 third-party/benchmark/src/sysinfo.cc | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/third-party/benchmark/src/sysinfo.cc b/third-party/benchmark/src/sysinfo.cc
index 2bed1663af2e95..22944a41376f60 100644
--- a/third-party/benchmark/src/sysinfo.cc
+++ b/third-party/benchmark/src/sysinfo.cc
@@ -520,6 +520,8 @@ int GetNumCPUsImpl() {
   }
 #if defined(__alpha__)
   const std::string Key = "cpus detected";
+#elif defined(__sparc__)
+  const std::string Key = "ncpus active";
 #else
   const std::string Key = "processor";
 #endif