libperf: Make libperf.a part of the perf build

Add an empty libperf.a under tools/perf/lib and link it with perf.

It can also be built separately with:

  $ cd tools/perf/lib && make
    CC       core.o
    LD       libperf-in.o
    AR       libperf.a
    LINK     libperf.so

Committer testing:

  $ make O=/tmp/build/perf -C tools/perf/lib/
  make: Entering directory '/home/acme/git/perf/tools/perf/lib'
    LINK     /tmp/build/perf/libperf.so
  make: Leaving directory '/home/acme/git/perf/tools/perf/lib'
  $ ls -la /tmp/build/perf/libperf.so
  -rwxrwxr-x. 1 acme acme 16232 Jul 22 15:30 /tmp/build/perf/libperf.so
  $ file /tmp/build/perf/libperf.so
  /tmp/build/perf/libperf.so: ELF 64-bit LSB shared object, x86-64, version 1 (SYSV), dynamically linked, BuildID[sha1]=7a51d227d871b381ddb686dcf94145c4dd908221, not stripped
  $ git status tools/perf
  On branch perf/core
  nothing to commit, working tree clean
  $
  $ ls -lart tools/perf/lib/
  total 16
  drwxrwxr-x. 16 acme acme 4096 Jul 22 15:29 ..
  -rw-rw-r--.  1 acme acme 1633 Jul 22 15:29 Makefile
  -rw-rw-r--.  1 acme acme    0 Jul 22 15:29 core.c
  -rw-rw-r--.  1 acme acme   20 Jul 22 15:29 Build
  drwxrwxr-x.  2 acme acme 4096 Jul 22 15:29 .
  $

Committer notes:

Need to add -I$(srctree)/tools/arch/$(ARCH)/include/uapi
-I$(srctree)/tools/include/uapi to tools/perf/lib/Makefile's INCLUDE
variable to pick up the latest versions of kernel headers, even in older
systems, this is in line with what is in tools/lib/bpf/Makefile.

Signed-off-by: Jiri Olsa <jolsa@kernel.org>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/20190721112506.12306-24-jolsa@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

1 files changed, 74 insertions, 0 deletions

diff --git a/tools/perf/lib/Makefile b/tools/perf/lib/Makefile
new file mode 100644
index 000000000000..33046e7c6a2a
--- /dev/null
+++ b/tools/perf/lib/Makefile
@@ -0,0 +1,74 @@
+# SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
+# Most of this file is copied from tools/lib/bpf/Makefile
+
+MAKEFLAGS += --no-print-directory
+
+ifeq ($(srctree),)
+srctree := $(patsubst %/,%,$(dir $(CURDIR)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+srctree := $(patsubst %/,%,$(dir $(srctree)))
+#$(info Determined 'srctree' to be $(srctree))
+endif
+
+include $(srctree)/tools/scripts/Makefile.include
+include $(srctree)/tools/scripts/Makefile.arch
+
+ifeq ("$(origin V)", "command line")
+  VERBOSE = $(V)
+endif
+ifndef VERBOSE
+  VERBOSE = 0
+endif
+
+ifeq ($(VERBOSE),1)
+  Q =
+else
+  Q = @
+endif
+
+# Set compile option CFLAGS
+ifdef EXTRA_CFLAGS
+  CFLAGS := $(EXTRA_CFLAGS)
+else
+  CFLAGS := -g -Wall
+endif
+
+INCLUDES = -I$(srctree)/tools/perf/lib/include -I$(srctree)/tools/include -I$(srctree)/tools/arch/$(ARCH)/include/ -I$(srctree)/tools/arch/$(ARCH)/include/uapi -I$(srctree)/tools/include/uapi
+
+# Append required CFLAGS
+override CFLAGS += $(EXTRA_WARNINGS)
+override CFLAGS += -Werror -Wall
+override CFLAGS += -fPIC
+override CFLAGS += $(INCLUDES)
+override CFLAGS += -fvisibility=hidden
+
+all:
+
+export srctree OUTPUT CC LD CFLAGS V
+include $(srctree)/tools/build/Makefile.include
+
+LIBPERF_SO := $(OUTPUT)libperf.so
+LIBPERF_A  := $(OUTPUT)libperf.a
+LIBPERF_IN := $(OUTPUT)libperf-in.o
+
+$(LIBPERF_IN): FORCE
+	$(Q)$(MAKE) $(build)=libperf
+
+$(LIBPERF_A): $(LIBPERF_IN)
+	$(QUIET_AR)$(RM) $@ && $(AR) rcs $@ $(LIBPERF_IN)
+
+$(LIBPERF_SO): $(LIBPERF_IN)
+	$(QUIET_LINK)$(CC) --shared -Wl,-soname,libperf.so $^ -o $@
+
+libs: $(LIBPERF_A) $(LIBPERF_SO)
+
+all: fixdep
+	$(Q)$(MAKE) libs
+
+clean:
+	$(call QUIET_CLEAN, libperf) $(RM) $(LIBPERF_A) \
+                *.o *~ *.a *.so .*.d .*.cmd LIBPERF-CFLAGS
+
+FORCE:
+
+.PHONY: all install clean FORCE