From b0618f38e2ab8ce3f094e4973955cfdbb55fceea Mon Sep 17 00:00:00 2001
From: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Tue, 9 May 2023 15:42:38 -0300
Subject: [PATCH] perf build: Gracefully fail the build if BUILD_BPF_SKEL=1 is
 specified and clang isn't available

Build BPF skels require having a compiler able to generate BPF bytecode,
and so far this is only possible with clang, so check for its
availability and fail the build when the user explicitely ask for BPF
skels to be built.

Acked-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Andrii Nakryiko <andrii.nakryiko@gmail.com>,
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Song Liu <songliubraving@meta.com>
Yang: Yang Jihong <yangjihong1@huawei.com>,
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
---
 tools/perf/Makefile.config | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 4884520f954f..70268442f7ee 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -216,6 +216,12 @@ ifeq ($(call get-executable,$(BISON)),)
   dummy := $(error Error: $(BISON) is missing on this system, please install it)
 endif
 
+ifeq ($(BUILD_BPF_SKEL),1)
+  ifeq ($(call get-executable,$(CLANG)),)
+    dummy := $(error $(CLANG) is missing on this system, please install it to be able to build with BUILD_BPF_SKEL=1)
+  endif
+endif
+
 ifneq ($(OUTPUT),)
   ifeq ($(shell expr $(shell $(BISON) --version | grep bison | sed -e 's/.\+ \([0-9]\+\).\([0-9]\+\).\([0-9]\+\)/\1\2\3/g') \>\= 371), 1)
     BISON_FILE_PREFIX_MAP := --file-prefix-map=$(OUTPUT)=
-- 
2.11.0