[PATCH 2/2 Resend] perf build: Support llvm and clang support compiled in

[Thomas Richter]

Perf build suports llvm and clang support compiled in.
Test case 56 builtin clang support provides a test case
which is always skipped.

Link perf with the latest llvm and clang libraries and
enable this test case.

Use 'make LIBCLANGLLVM=1' to include this support.

V2: Add Library patch before -lclang-cpp

Output before:
 # ./perf test 56
 56: builtin clang support                  :
 56.1: builtin clang compile C source to IR : Skip (not compiled in)
 56.2: builtin clang compile C source to ELF object: \
	 				Skip (not compiled in)

Output after:
 # ./perf test 56
 56: builtin clang support                          :
 56.1: builtin clang compile C source to IR         : Ok
 56.2: builtin clang compile C source to ELF object : Ok
 #

Signed-off-by: Thomas Richter <tmricht@xxxxxxxxxxxxx>
Cc: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>

>From Ian Rogers
Build tested with LLVM 14 and 15 using:
BUILD_BPF_SKEL=1 LIBCLANGLLVM=1 LLVM_CONFIG=llvm-config-14
BUILD_BPF_SKEL=1 LIBCLANGLLVM=1 LLVM_CONFIG=llvm-config-15

Tested-by: Ian Rogers <irogers@xxxxxxxxxx>
---
 tools/perf/Makefile.config | 2 +-
 tools/perf/Makefile.perf   | 5 +----
 2 files changed, 2 insertions(+), 5 deletions(-)

diff --git a/tools/perf/Makefile.config b/tools/perf/Makefile.config
index c5db0de49868..8e1d1fab9b4d 100644
--- a/tools/perf/Makefile.config
+++ b/tools/perf/Makefile.config
@@ -325,7 +325,7 @@ CORE_CFLAGS += -Wall
 CORE_CFLAGS += -Wextra
 CORE_CFLAGS += -std=gnu11
 
-CXXFLAGS += -std=gnu++14 -fno-exceptions -fno-rtti
+CXXFLAGS += -std=gnu++17 -fno-exceptions -fno-rtti
 CXXFLAGS += -Wall
 CXXFLAGS += -fno-omit-frame-pointer
 CXXFLAGS += -ggdb3
diff --git a/tools/perf/Makefile.perf b/tools/perf/Makefile.perf
index 097316ef38e6..158a0733fc9d 100644
--- a/tools/perf/Makefile.perf
+++ b/tools/perf/Makefile.perf
@@ -426,10 +426,7 @@ EXTLIBS := $(call filter-out,$(EXCLUDE_EXTLIBS),$(EXTLIBS))
 LIBS = -Wl,--whole-archive $(PERFLIBS) $(EXTRA_PERFLIBS) -Wl,--no-whole-archive -Wl,--start-group $(EXTLIBS) -Wl,--end-group
 
 ifeq ($(USE_CLANG), 1)
-  CLANGLIBS_LIST = AST Basic CodeGen Driver Frontend Lex Tooling Edit Sema Analysis Parse Serialization
-  CLANGLIBS_NOEXT_LIST = $(foreach l,$(CLANGLIBS_LIST),$(shell $(LLVM_CONFIG) --libdir)/libclang$(l))
-  LIBCLANG = $(foreach l,$(CLANGLIBS_NOEXT_LIST),$(wildcard $(l).a $(l).so))
-  LIBS += -Wl,--start-group $(LIBCLANG) -Wl,--end-group
+  LIBS += -L$(shell $(LLVM_CONFIG) --libdir) -lclang-cpp
 endif
 
 ifeq ($(USE_LLVM), 1)
-- 
2.41.0