[PATCH 1/1] tools build: Fix rust feature detection

[Arnaldo Carvalho de Melo <acme@kernel.org>]

Features in FEATURE_TESTS_BASIC will be set as being available if
test-all.c builds, so since the rust test isn't included in test-all.c,
we can't have 'rust' in there, remove it from FEATURE_TESTS_BASIC and
use feature-check so that it tries to build test-rust.bin, doing the
actual feature detection.

On a system lacking a rust compiler:

  Makefile.config:1158: Rust is not found. Test workloads with rust are disabled.

  Auto-detecting system features:
  ...                                   libdw: [ on  ]
  ...                                   glibc: [ on  ]
  ...                                  libelf: [ on  ]
  ...                                 libnuma: [ on  ]
  ...                  numa_num_possible_cpus: [ on  ]
  ...                               libpython: [ on  ]
  ...                             libcapstone: [ on  ]
  ...                               llvm-perf: [ on  ]
  ...                                    zlib: [ on  ]
  ...                                    lzma: [ on  ]
  ...                                     bpf: [ on  ]
  ...                                  libaio: [ on  ]
  ...                                 libzstd: [ on  ]
  ...                              libopenssl: [ on  ]
  ...                                    rust: [ OFF ]

  $ cat /tmp/build/perf-tools-next/feature/test-rust.make.output
  /bin/sh: line 1: rustc: command not found
  $ file /tmp/build/perf-tools-next/feature/test-rust.bin
  /tmp/build/perf-tools-next/feature/test-rust.bin: cannot open `/tmp/build/perf-tools-next/feature/test-rust.bin' (No such file or directory)
  $
  $ perf -vv | grep RUST
                  rust: [ OFF ]  # HAVE_RUST_SUPPORT
  $

And after installing it:

  ...                                    rust: [ on  ]

  $ cat /tmp/build/perf-tools-next/feature/test-rust.make.output
  $ file /tmp/build/perf-tools-next/feature/test-rust.bin
/tmp/build/perf-tools-next/feature/test-rust.bin: ELF 64-bit LSB pie executable, x86-64, version 1 (SYSV), dynamically linked, interpreter /lib64/ld-linux-x86-64.so.2, BuildID[sha1]=9c416edf673ee3705b97bae893a99a6fcf1ee258, for GNU/Linux 3.2.0, with debug_info, not stripped
  $
  $ perf -vv | grep RUST
                  rust: [ on  ]  # HAVE_RUST_SUPPORT
  $

Fixes: 6a32fa5ccd33da5d ("tools build: Add a feature test for rust compiler")
Cc: Dmitrii Dolgov <9erthalion6@gmail.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/build/Makefile.feature | 3 +--
 tools/perf/Makefile.config   | 1 +
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index 64d21152fc81aad6..0b7a7c38cb88a7d0 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -100,8 +100,7 @@ FEATURE_TESTS_BASIC :=                  \
         disassembler-four-args		\
         disassembler-init-styled	\
         file-handle			\
-        libopenssl			\
-        rust
+        libopenssl
 
 # FEATURE_TESTS_BASIC + FEATURE_TESTS_EXTRA is the complete list
 # of all feature tests
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 94aecfe38b95f716..a8dc72cfe48eec52 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -1154,6 +1154,7 @@ ifneq ($(NO_LIBTRACEEVENT),1)
 endif
 
 ifndef NO_RUST
+  $(call feature_check,rust)
   ifneq ($(feature-rust), 1)
     $(warning Rust is not found. Test workloads with rust are disabled.)
     NO_RUST := 1
-- 
2.53.0