perf build: Combine test-dwarf-getcfi into test-libdw

dwarf_getcfi support in libdw is 15 years old. Make libdw imply
dwarf_getcfi support and simplify build logic.

Signed-off-by: Ian Rogers <[e-mail]>
Acked-by: Namhyung Kim <[e-mail]>
Tested-by: Leo Yan <[e-mail]>
Cc: Anup Patel <[e-mail]>
Cc: Yang Jihong <[e-mail]>
Cc: Palmer Dabbelt <[e-mail]>
Cc: David S. Miller <[e-mail]>
Cc: Albert Ou <[e-mail]>
Cc: Shenlin Liang <[e-mail]>
Cc: Nick Terrell <[e-mail]>
Cc: Guilherme Amadio <[e-mail]>
Cc: Steinar H. Gunderson <[e-mail]>
Cc: Changbin Du <[e-mail]>
Cc: Alexander Lobakin <[e-mail]>
Cc: Przemek Kitszel <[e-mail]>
Cc: Huacai Chen <[e-mail]>
Cc: Guo Ren <[e-mail]>
Cc: Masahiro Yamada <[e-mail]>
Cc: Masami Hiramatsu (Google) <[e-mail]>
Cc: Will Deacon <[e-mail]>
Cc: James Clark <[e-mail]>
Cc: Mike Leach <[e-mail]>
Cc: Chen Pei <[e-mail]>
Cc: Leo Yan <[e-mail]>
Cc: Oliver Upton <[e-mail]>
Cc: Aditya Gupta <[e-mail]>
Cc: Kajol Jain <[e-mail]>
Cc: Athira Rajeev <[e-mail]>
Cc: [e-mail]
Cc: [e-mail]
Cc: Bibo Mao <[e-mail]>
Cc: John Garry <[e-mail]>
Cc: Atish Patra <[e-mail]>
Cc: Dima Kogan <[e-mail]>
Cc: Paul Walmsley <[e-mail]>
Cc: Dr. David Alan Gilbert <[e-mail]>
Cc: [e-mail]
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Namhyung Kim <[e-mail]>

tools/build/Makefile.feature

···
 FEATURE_TESTS_BASIC :=                  \
         backtrace                       \
         libdw                           \
-        dwarf_getcfi                    \
         eventfd                         \
         fortify-source                  \
         get_current_dir_name            \

tools/build/feature/Makefile

···
          test-backtrace.bin                     \
          test-bionic.bin                        \
          test-libdw.bin                         \
-         test-dwarf_getcfi.bin                  \
          test-eventfd.bin                       \
          test-fortify-source.bin                \
          test-get_current_dir_name.bin          \
···
 endif
 
 $(OUTPUT)test-libdw.bin:
-	$(BUILD) $(DWLIBS)
-
-$(OUTPUT)test-dwarf_getcfi.bin:
 	$(BUILD) $(DWLIBS)
 
 $(OUTPUT)test-libelf-getphdrnum.bin:

tools/build/feature/test-dwarf_getcfi.c

···
-// SPDX-License-Identifier: GPL-2.0
-#include <stdio.h>
-#include <elfutils/libdw.h>
-
-int main(void)
-{
-	Dwarf *dwarf = NULL;
-	return dwarf_getcfi(dwarf) == NULL;
-}

tools/build/feature/test-libdw.c

···
 	return (int)dwarf_getlocations(&attr, offset, &base, &start, &end, &op, &nops);
 }
 
+int test_libdw_getcfi(void)
+{
+	Dwarf *dwarf = NULL;
+
+	return dwarf_getcfi(dwarf) == NULL;
+}
+
 int main(void)
 {
-	return test_libdw() + test_libdw_unwind() + test_libdw_getlocations();
+	return test_libdw() + test_libdw_unwind() + test_libdw_getlocations() +
+	       test_libdw_getcfi();
 }

tools/perf/Makefile.config

···
 endif
 FEATURE_CHECK_CFLAGS-libdw := $(LIBDW_CFLAGS)
 FEATURE_CHECK_LDFLAGS-libdw := $(LIBDW_LDFLAGS) $(DWARFLIBS)
-FEATURE_CHECK_CFLAGS-dwarf_getcfi := $(LIBDW_CFLAGS)
-FEATURE_CHECK_LDFLAGS-dwarf_getcfi := $(LIBDW_LDFLAGS) $(DWARFLIBS)
 
 # for linking with debug library, run like:
 # make DEBUG=1 LIBBABELTRACE_DIR=/opt/libbabeltrace/
···
       endif
     else
       CFLAGS += -DHAVE_DWARF_GETLOCATIONS_SUPPORT
-      ifneq ($(feature-dwarf_getcfi), 1)
-        $(warning Old libdw.h, finding variables at given 'perf probe' point will not work, install elfutils-devel/libdw-dev >= 0.142)
-      else
-        CFLAGS += -DHAVE_DWARF_CFI_SUPPORT
-      endif # dwarf_getcfi
+      CFLAGS += -DHAVE_DWARF_CFI_SUPPORT
     endif # Dwarf support
   endif # libelf support
 endif # NO_LIBELF