perf build: Autodetect minimum required llvm-dev version

The new LLVM addr2line feature requires a minimum version of 13 to
compile. Add a feature check for the version so that NO_LLVM=1 doesn't
need to be explicitly added. Leave the existing llvm feature check
intact because it's used by tools other than Perf.

This fixes the following compilation error when the llvm-dev version
doesn't match:

  util/llvm-c-helpers.cpp: In function 'char* llvm_name_for_code(dso*, const char*, u64)':
  util/llvm-c-helpers.cpp:178:21: error: 'std::remove_reference_t<llvm::DILineInfo>' {aka 'struct llvm::DILineInfo'} has no member named 'StartAddress'
    178 |   addr, res_or_err->StartAddress ? *res_or_err->StartAddress : 0);

Fixes: c3f8644 ("perf report: Support LLVM for addr2line()")
Signed-off-by: James Clark <[email protected]>
Tested-by: Arnaldo Carvalho de Melo <[email protected]>
Cc: Adrian Hunter <[email protected]>
Cc: Alexander Shishkin <[email protected]>
Cc: Bill Wendling <[email protected]>
Cc: Changbin Du <[email protected]>
Cc: Guilherme Amadio <[email protected]>
Cc: Ian Rogers <[email protected]>
Cc: Ingo Molnar <[email protected]>
Cc: Jiri Olsa <[email protected]>
Cc: Justin Stitt <[email protected]>
Cc: Kan Liang <[email protected]>
Cc: Leo Yan <[email protected]>
Cc: Manu Bretelle <[email protected]>
Cc: Mark Rutland <[email protected]>
Cc: Masami Hiramatsu <[email protected]>
Cc: Namhyung Kim <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Nick Desaulniers <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Quentin Monnet <[email protected]>
Cc: Steinar H. Gunderson <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Arnaldo Carvalho de Melo <[email protected]>

Author: james-c-linaro

tools/build/Makefile.feature

@@ -136,7 +136,7 @@ FEATURE_DISPLAY ?=              \
          libunwind              \
          libdw-dwarf-unwind     \
          libcapstone            \
-         llvm                   \
+         llvm-perf              \
          zlib                   \
          lzma                   \
          get_cpuid              \

tools/build/feature/Makefile

@@ -73,6 +73,7 @@ FILES=                                          \
          test-libopencsd.bin			\
          test-clang.bin				\
          test-llvm.bin				\
+         test-llvm-perf.bin   \
          test-llvm-version.bin			\
          test-libaio.bin			\
          test-libzstd.bin			\
@@ -388,6 +389,14 @@ $(OUTPUT)test-llvm.bin:
 		$(shell $(LLVM_CONFIG) --system-libs)		\
 		> $(@:.bin=.make.output) 2>&1
 
+$(OUTPUT)test-llvm-perf.bin:
+	$(BUILDXX) -std=gnu++17 				\
+		-I$(shell $(LLVM_CONFIG) --includedir) 		\
+		-L$(shell $(LLVM_CONFIG) --libdir)		\
+		$(shell $(LLVM_CONFIG) --libs Core BPF)		\
+		$(shell $(LLVM_CONFIG) --system-libs)		\
+		> $(@:.bin=.make.output) 2>&1
+
 $(OUTPUT)test-llvm-version.bin:
 	$(BUILDXX) -std=gnu++17					\
 		-I$(shell $(LLVM_CONFIG) --includedir)		\

tools/build/feature/test-llvm-perf.cpp

@@ -0,0 +1,14 @@
+// SPDX-License-Identifier: GPL-2.0
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/raw_ostream.h"
+
+#if LLVM_VERSION_MAJOR < 13
+# error "Perf requires llvm-devel/llvm-dev version 13 or greater"
+#endif
+
+int main()
+{
+	llvm::errs() << "Hello World!\n";
+	llvm::llvm_shutdown();
+	return 0;
+}

tools/perf/Makefile.config

@@ -981,8 +981,8 @@ ifdef BUILD_NONDISTRO
 endif
 
 ifndef NO_LIBLLVM
-  $(call feature_check,llvm)
-  ifeq ($(feature-llvm), 1)
+  $(call feature_check,llvm-perf)
+  ifeq ($(feature-llvm-perf), 1)
     CFLAGS += -DHAVE_LIBLLVM_SUPPORT
     CFLAGS += $(shell $(LLVM_CONFIG) --cflags)
     CXXFLAGS += -DHAVE_LIBLLVM_SUPPORT
@@ -992,7 +992,7 @@ ifndef NO_LIBLLVM
     EXTLIBS += -lstdc++
     $(call detected,CONFIG_LIBLLVM)
   else
-    $(warning No libllvm found, slower source file resolution, please install llvm-devel/llvm-dev)
+    $(warning No libllvm 13+ found, slower source file resolution, please install llvm-devel/llvm-dev)
     NO_LIBLLVM := 1
   endif
 endif