[PATCH 02/14] perf tools: Add feature detection for g++

From: Wang Nan
Date: Fri Sep 23 2016 - 08:52:27 EST


Check if g++ is available. The result will be used by builtin clang and
LLVM support. Since LLVM requires C++11, this feature detector checks
std::move().

Signed-off-by: Wang Nan <wangnan0@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxxxx>
Cc: He Kuang <hekuang@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
---
tools/build/Makefile.feature | 2 +-
tools/build/feature/Makefile | 10 +++++++++-
tools/build/feature/test-cxx.cpp | 15 +++++++++++++++
3 files changed, 25 insertions(+), 2 deletions(-)
create mode 100644 tools/build/feature/test-cxx.cpp

diff --git a/tools/build/Makefile.feature b/tools/build/Makefile.feature
index a120c6b..ae52e02 100644
--- a/tools/build/Makefile.feature
+++ b/tools/build/Makefile.feature
@@ -7,7 +7,7 @@ endif

feature_check = $(eval $(feature_check_code))
define feature_check_code
- feature-$(1) := $(shell $(MAKE) OUTPUT=$(OUTPUT_FEATURES) CFLAGS="$(EXTRA_CFLAGS) $(FEATURE_CHECK_CFLAGS-$(1))" LDFLAGS="$(LDFLAGS) $(FEATURE_CHECK_LDFLAGS-$(1))" -C $(feature_dir) $(OUTPUT_FEATURES)test-$1.bin >/dev/null 2>/dev/null && echo 1 || echo 0)
+ feature-$(1) := $(shell $(MAKE) OUTPUT=$(OUTPUT_FEATURES) CFLAGS="$(EXTRA_CFLAGS) $(FEATURE_CHECK_CFLAGS-$(1))" CXXFLAGS="$(EXTRA_CXXFLAGS) $(FEATURE_CHECK_CXXFLAGS-$(1))" LDFLAGS="$(LDFLAGS) $(FEATURE_CHECK_LDFLAGS-$(1))" -C $(feature_dir) $(OUTPUT_FEATURES)test-$1.bin >/dev/null 2>/dev/null && echo 1 || echo 0)
endef

feature_set = $(eval $(feature_set_code))
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index a0b29a3..ac9c477 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -46,11 +46,13 @@ FILES= \
test-lzma.bin \
test-bpf.bin \
test-get_cpuid.bin \
- test-sdt.bin
+ test-sdt.bin \
+ test-cxx.bin

FILES := $(addprefix $(OUTPUT),$(FILES))

CC := $(CROSS_COMPILE)gcc -MD
+CXX := $(CROSS_COMPILE)g++ -MD
PKG_CONFIG := $(CROSS_COMPILE)pkg-config

all: $(FILES)
@@ -58,6 +60,9 @@ all: $(FILES)
__BUILD = $(CC) $(CFLAGS) -Wall -Werror -o $@ $(patsubst %.bin,%.c,$(@F)) $(LDFLAGS)
BUILD = $(__BUILD) > $(@:.bin=.make.output) 2>&1

+__BUILDXX = $(CXX) $(CXXFLAGS) -Wall -Werror -o $@ $(patsubst %.bin,%.cpp,$(@F)) $(LDFLAGS)
+ BUILDXX = $(__BUILDXX) > $(@:.bin=.make.output) 2>&1
+
###############################

$(OUTPUT)test-all.bin:
@@ -217,6 +222,9 @@ $(OUTPUT)test-bpf.bin:
$(OUTPUT)test-sdt.bin:
$(BUILD)

+$(OUTPUT)test-cxx.bin:
+ $(BUILDXX) -std=gnu++11
+
-include $(OUTPUT)*.d

###############################
diff --git a/tools/build/feature/test-cxx.cpp b/tools/build/feature/test-cxx.cpp
new file mode 100644
index 0000000..b1dee9a
--- /dev/null
+++ b/tools/build/feature/test-cxx.cpp
@@ -0,0 +1,15 @@
+#include <iostream>
+#include <memory>
+
+static void print_str(std::string s)
+{
+ std::cout << s << std::endl;
+}
+
+int main()
+{
+ std::string s("Hello World!");
+ print_str(std::move(s));
+ std::cout << "|" << s << "|" << std::endl;
+ return 0;
+}
--
1.8.3.4