[RFC PATCH 3/6] tools: build perf in tools_build

[Sasha Levin <sashal@kernel.org>]

Add CONFIG_TOOLS_BUILD_PERF. perf is built as it is built standalone,
with optional features enabled when their libraries are installed, and
with -Werror following CONFIG_WERROR. The feature table is left out of
the kernel build log.

CONFIG_TOOLS_BUILD_PERF_MINIMAL turns every optional feature off
instead, so the result does not depend on the build machine. allmodconfig
and allyesconfig turn it on.

Assisted-by: LLM
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 tools/Kconfig         | 15 +++++++++++++++
 tools/Makefile.kbuild | 19 +++++++++++++++++++
 2 files changed, 34 insertions(+)

diff --git a/tools/Kconfig b/tools/Kconfig
index bf0643b39b86e..488f439592150 100644
--- a/tools/Kconfig
+++ b/tools/Kconfig
@@ -59,6 +59,21 @@ config TOOLS_BUILD_IIO
 	help
 	  Build tools/iio (lsiio, iio_event_monitor, iio_generic_buffer).
 
+config TOOLS_BUILD_PERF
+	bool "perf"
+	help
+	  Build tools/perf. As in a standalone perf build, optional
+	  features are enabled when the libraries they need are installed.
+
+config TOOLS_BUILD_PERF_MINIMAL
+	bool "Build perf with all optional features disabled"
+	depends on TOOLS_BUILD_PERF
+	help
+	  Turn off every optional perf feature, so that the result does
+	  not depend on which libraries the build machine has installed.
+	  allmodconfig and allyesconfig turn this on, which keeps their
+	  builds the same on every machine.
+
 config TOOLS_BUILD_SPI
 	bool "SPI tools"
 	help
diff --git a/tools/Makefile.kbuild b/tools/Makefile.kbuild
index 820a2d9a3893b..62fd494253eca 100644
--- a/tools/Makefile.kbuild
+++ b/tools/Makefile.kbuild
@@ -73,6 +73,25 @@ PHONY += $(tool-targets)
 $(tool-targets): tool-%: FORCE
 	$(call build,$(outdir)/$*,-C $(toolsdir)/$* O=$(outdir)/$* CC='$(call escsq,$(tools-cc))',,TOOLS_BUILD_$(shell echo $* | tr a-z A-Z))
 
+# perf, without the feature table in the kernel build log
+perf-flags := CC='$(call escsq,$(tools-cc))' FEATURE_DISPLAY= WERROR=$(if $(CONFIG_WERROR),1,0)
+
+# Every optional feature off, so the result does not depend on which
+# libraries are installed
+perf-flags-$(CONFIG_TOOLS_BUILD_PERF_MINIMAL) += \
+	NO_LIBELF=1 NO_LIBTRACEEVENT=1 NO_JEVENTS=1 NO_LIBPYTHON=1 NO_LIBDW=1 \
+	NO_LIBBPF=1 BUILD_BPF_SKEL=0 NO_SLANG=1 NO_GTK2=1 NO_AIO=1 \
+	NO_BACKTRACE=1 NO_DEMANGLE=1 NO_LZMA=1 NO_LIBZSTD=1 NO_ZLIB=1 \
+	NO_LIBNUMA=1 NO_LIBUNWIND=1 NO_LIBLLVM=1 NO_CAPSTONE=1 NO_LIBPFM4=1 \
+	NO_SDT=1 NO_JVMTI=1 NO_LIBDEBUGINFOD=1 NO_BABELTRACE2=1 NO_RUST=1 \
+	NO_SHELLCHECK=1 NO_PERF_READ_VDSO32=1 NO_PERF_READ_VDSOX32=1
+
+__tools_build: $(if $(CONFIG_TOOLS_BUILD_PERF),perf)
+
+PHONY += perf
+perf: FORCE
+	$(call build,$(outdir)/perf,-C $(toolsdir)/perf -f Makefile.perf O=$(outdir)/perf $(perf-flags) $(perf-flags-y),,TOOLS_BUILD_PERF)
+
 PHONY += FORCE
 FORCE:
 
-- 
2.53.0