tools build: Make libperl opt-in rather than opt-out, deprecate

If libperl is installed then the perf tool build will build against
it. There appears to be limited interest in the scripting support for
perl so let's make it opt-in and deprecate it.

With this patch applied you need to add LIBPERL=1 to get libperl
support in perf - there is no warning if libperl is missing, but
building will fail if libperl is missing and the build has LIBPERL=1.
The perf version output is changed to:
```
$ perf version --build-options
perf version 6.17.rc3.g8eca69269947
                   aio: [ on  ]  # HAVE_AIO_SUPPORT
                   bpf: [ on  ]  # HAVE_LIBBPF_SUPPORT
         bpf_skeletons: [ on  ]  # HAVE_BPF_SKEL
            debuginfod: [ on  ]  # HAVE_DEBUGINFOD_SUPPORT
                 dwarf: [ on  ]  # HAVE_LIBDW_SUPPORT
    dwarf_getlocations: [ on  ]  # HAVE_LIBDW_SUPPORT
          dwarf-unwind: [ on  ]  # HAVE_DWARF_UNWIND_SUPPORT
              auxtrace: [ on  ]  # HAVE_AUXTRACE_SUPPORT
                libbfd: [ OFF ]  # HAVE_LIBBFD_SUPPORT ( tip: Deprecated, license incompatibility, use BUILD_NONDISTRO=1 and install binutils-dev[el] )
        libbpf-strings: [ on  ]  # HAVE_LIBBPF_STRINGS_SUPPORT
           libcapstone: [ on  ]  # HAVE_LIBCAPSTONE_SUPPORT
    libdw-dwarf-unwind: [ on  ]  # HAVE_LIBDW_SUPPORT
                libelf: [ on  ]  # HAVE_LIBELF_SUPPORT
               libnuma: [ on  ]  # HAVE_LIBNUMA_SUPPORT
            libopencsd: [ OFF ]  # HAVE_CSTRACE_SUPPORT
               libperl: [ OFF ]  # HAVE_LIBPERL_SUPPORT ( tip:
Deprecated, use LIBPERL=1 and install libperl-dev to build with it )
               libpfm4: [ on  ]  # HAVE_LIBPFM
             libpython: [ on  ]  # HAVE_LIBPYTHON_SUPPORT
              libslang: [ on  ]  # HAVE_SLANG_SUPPORT
         libtraceevent: [ on  ]  # HAVE_LIBTRACEEVENT
             libunwind: [ OFF ]  # HAVE_LIBUNWIND_SUPPORT ( tip:
Deprecated, use LIBUNWIND=1 and install libunwind-dev[el] to build
with it )
                  lzma: [ on  ]  # HAVE_LZMA_SUPPORT
numa_num_possible_cpus: [ on  ]  # HAVE_LIBNUMA_SUPPORT
                  zlib: [ on  ]  # HAVE_ZLIB_SUPPORT
                  zstd: [ on  ]  # HAVE_ZSTD_SUPPORT
```

i.e. there is a tip saying about deprecation and how to get support
back.

Signed-off-by: Ian Rogers <irogers@google.com>
Tested-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Charlie Jenkins <charlie@rivosinc.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@linaro.org>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@arm.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Michael Petlan <mpetlan@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Quentin Monnet <qmo@kernel.org>
Cc: Steven Rostedt (VMware) <rostedt@goodmis.org>
Cc: Tomas Glozar <tglozar@redhat.com>
Cc: Yuzhuo Jing <yuzhuo@google.com>
Link: https://lore.kernel.org/lkml/aMrk03gigBlGcYLK@x1/
Link: https://lore.kernel.org/lkml/CAP-5=fVX+bLBRJCiziDi_hBySgv2NFtDoghtpheSSxVAvvETGw@mail.gmail.com
[ Keep the pre-existing perl-ExtUtils-Embed hint for Fedora/RHEL systems ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

6 files changed, 13 insertions, 25 deletions

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index 649c5ab8e8f2..9c1a69d26f51 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -80,7 +80,6 @@ FEATURE_TESTS_BASIC :=                  \
         libelf-zstd                     \
         libnuma                         \
         numa_num_possible_cpus          \
-        libperl                         \
         libpython                       \
         libslang                        \
         libtraceevent                   \
@@ -121,6 +120,7 @@ FEATURE_TESTS_EXTRA :=                  \
          libbfd-liberty                 \
          libbfd-liberty-z               \
          libopencsd                     \
+         libperl                        \
          cxx                            \
          llvm                           \
          clang                          \
@@ -144,7 +144,6 @@ FEATURE_DISPLAY ?=              \
          libelf                 \
          libnuma                \
          numa_num_possible_cpus \
-         libperl                \
          libpython              \
          libcapstone            \
          llvm-perf              \
diff --git a/tools/build/feature/test-all.c b/tools/build/feature/test-all.c
index 4419fb4710bd..e1847db6f8e6 100644
--- a/tools/build/feature/test-all.c
+++ b/tools/build/feature/test-all.c
@@ -7,17 +7,13 @@
  */
 
 /*
- * Quirk: Python and Perl headers cannot be in arbitrary places, so keep
- * these 3 testcases at the top:
+ * Quirk: Python headers cannot be in arbitrary places, so keep this testcase at
+ * the top:
  */
 #define main main_test_libpython
 # include "test-libpython.c"
 #undef main
 
-#define main main_test_libperl
-# include "test-libperl.c"
-#undef main
-
 #define main main_test_hello
 # include "test-hello.c"
 #undef main
@@ -161,7 +157,6 @@
 int main(int argc, char *argv[])
 {
 	main_test_libpython();
-	main_test_libperl();
 	main_test_hello();
 	main_test_libelf();
 	main_test_get_current_dir_name();
diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index 5a5832ee7b53..0f4b297fbacc 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -817,9 +817,7 @@ ifdef GTK2
   endif
 endif
 
-ifdef NO_LIBPERL
-  CFLAGS += -DNO_LIBPERL
-else
+ifdef LIBPERL
   PERL_EMBED_LDOPTS = $(shell perl -MExtUtils::Embed -e ldopts 2>/dev/null)
   PERL_EMBED_LDFLAGS = $(call strip-libs,$(PERL_EMBED_LDOPTS))
   PERL_EMBED_LIBADD = $(call grep-libs,$(PERL_EMBED_LDOPTS))
@@ -829,17 +827,13 @@ else
   PERL_EMBED_LDOPTS := $(filter-out -specs=%,$(PERL_EMBED_LDOPTS))
   FLAGS_PERL_EMBED=$(PERL_EMBED_CCOPTS) $(PERL_EMBED_LDOPTS)
 
+  $(call feature_check,libperl)
   ifneq ($(feature-libperl), 1)
-    CFLAGS += -DNO_LIBPERL
-    NO_LIBPERL := 1
-    $(warning Missing perl devel files. Disabling perl scripting support, please install perl-ExtUtils-Embed/libperl-dev)
+    $(error Missing perl devel files. Please install perl-ExtUtils-Embed/libperl-dev)
   else
     LDFLAGS += $(PERL_EMBED_LDFLAGS)
     EXTLIBS += $(PERL_EMBED_LIBADD)
     CFLAGS += -DHAVE_LIBPERL_SUPPORT
-    ifeq ($(CC_NO_CLANG), 0)
-      CFLAGS += -Wno-compound-token-split-by-macro
-    endif
     $(call detected,CONFIG_LIBPERL)
   endif
 endif
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index e2150acc2c13..7d6ac03a7109 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -17,7 +17,7 @@ include ../scripts/utilities.mak
 #
 # Define CROSS_COMPILE as prefix name of compiler if you want cross-builds.
 #
-# Define NO_LIBPERL to disable perl script extension.
+# Define LIBPERL to enable perl script extension.
 #
 # Define NO_LIBPYTHON to disable python script extension.
 #
@@ -1103,7 +1103,7 @@ endif
 		$(INSTALL) $(OUTPUT)perf-archive -t '$(DESTDIR_SQ)$(perfexec_instdir_SQ)'
 	$(call QUIET_INSTALL, perf-iostat) \
 		$(INSTALL) $(OUTPUT)perf-iostat -t '$(DESTDIR_SQ)$(perfexec_instdir_SQ)'
-ifndef NO_LIBPERL
+ifdef LIBPERL
 	$(call QUIET_INSTALL, perl-scripts) \
 		$(INSTALL) -d -m 755 '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/scripts/perl/Perf-Trace-Util/lib/Perf/Trace'; \
 		$(INSTALL) scripts/perl/Perf-Trace-Util/lib/Perf/Trace/* -m 644 -t '$(DESTDIR_SQ)$(perfexec_instdir_SQ)/scripts/perl/Perf-Trace-Util/lib/Perf/Trace'; \
diff --git a/tools/perf/builtin-check.c b/tools/perf/builtin-check.c
index b1e205871ab1..7fd054760e47 100644
--- a/tools/perf/builtin-check.c
+++ b/tools/perf/builtin-check.c
@@ -49,7 +49,7 @@ struct feature_status supported_features[] = {
 	FEATURE_STATUS("libelf", HAVE_LIBELF_SUPPORT),
 	FEATURE_STATUS("libnuma", HAVE_LIBNUMA_SUPPORT),
 	FEATURE_STATUS("libopencsd", HAVE_CSTRACE_SUPPORT),
-	FEATURE_STATUS("libperl", HAVE_LIBPERL_SUPPORT),
+	FEATURE_STATUS_TIP("libperl", HAVE_LIBPERL_SUPPORT, "Deprecated, use LIBPERL=1 and install perl-ExtUtils-Embed/libperl-dev to build with it"),
 	FEATURE_STATUS("libpfm4", HAVE_LIBPFM),
 	FEATURE_STATUS("libpython", HAVE_LIBPYTHON_SUPPORT),
 	FEATURE_STATUS("libslang", HAVE_SLANG_SUPPORT),
diff --git a/tools/perf/tests/make b/tools/perf/tests/make
index c574a678c28a..b650ce8864ed 100644
--- a/tools/perf/tests/make
+++ b/tools/perf/tests/make
@@ -73,9 +73,9 @@ make_extra_tests    := EXTRA_TESTS=1
 make_jevents_all    := JEVENTS_ARCH=all
 make_no_bpf_skel    := BUILD_BPF_SKEL=0
 make_gen_vmlinux_h  := GEN_VMLINUX_H=1
-make_no_libperl     := NO_LIBPERL=1
+make_libperl        := LIBPERL=1
 make_no_libpython   := NO_LIBPYTHON=1
-make_no_scripts     := NO_LIBPYTHON=1 NO_LIBPERL=1
+make_no_scripts     := NO_LIBPYTHON=1
 make_no_slang       := NO_SLANG=1
 make_no_gtk2        := NO_GTK2=1
 make_no_ui          := NO_SLANG=1 NO_GTK2=1
@@ -118,7 +118,7 @@ make_install_prefix_slash := install prefix=/tmp/krava/
 make_static         := LDFLAGS=-static NO_PERF_READ_VDSO32=1 NO_PERF_READ_VDSOX32=1 NO_JVMTI=1 NO_LIBTRACEEVENT=1 NO_LIBELF=1
 
 # all the NO_* variable combined
-make_minimal        := NO_LIBPERL=1 NO_LIBPYTHON=1 NO_GTK2=1
+make_minimal        := NO_LIBPYTHON=1 NO_GTK2=1
 make_minimal        += NO_DEMANGLE=1 NO_LIBELF=1 NO_BACKTRACE=1
 make_minimal        += NO_LIBNUMA=1 NO_LIBBIONIC=1 NO_LIBDW=1
 make_minimal        += NO_LIBDW_DWARF_UNWIND=1 NO_AUXTRACE=1 NO_LIBBPF=1
@@ -143,7 +143,7 @@ run += make_extra_tests
 run += make_jevents_all
 run += make_no_bpf_skel
 run += make_gen_vmlinux_h
-run += make_no_libperl
+run += make_libperl
 run += make_no_libpython
 run += make_no_scripts
 run += make_no_slang