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authorWang Nan <wangnan0@huawei.com>2016-11-26 07:03:31 +0000
committerArnaldo Carvalho de Melo <acme@redhat.com>2016-12-05 15:51:42 -0300
commitcb40d55b595cd117ef7c1880247605875b2115e8 (patch)
treed5ba1a94d6f7d451f95e70feb17b93a7d5da65b0 /tools/build
parent2bd42de0e196f89994cbae1990d2c7c5a9b6a529 (diff)
downloadlinux-cb40d55b595cd117ef7c1880247605875b2115e8.tar.bz2
tools build: Add feature detection for LLVM
Check if basic LLVM compiling environment is ready. Use llvm-config to detect include and library directories. Avoid using 'llvm-config --cxxflags' because its result contain some unwanted flags like --sysroot (if LLVM is built by yocto). Use '?=' to set LLVM_CONFIG, so explicitly passing LLVM_CONFIG to make would override it. Use 'llvm-config --libs BPF' to check if BPF backend is compiled in. Since now BPF bytecode is the only required backend, no need to waste time linking llvm and clang if BPF backend is missing. This also introduce an implicit requirement that LLVM should be new enough. Old LLVM doesn't support BPF backend. Signed-off-by: Wang Nan <wangnan0@huawei.com> Cc: Alexei Starovoitov <ast@fb.com> Cc: He Kuang <hekuang@huawei.com> Cc: Jiri Olsa <jolsa@kernel.org> Cc: Joe Stringer <joe@ovn.org> Cc: Zefan Li <lizefan@huawei.com> Cc: pi3orama@163.com Link: http://lkml.kernel.org/r/20161126070354.141764-8-wangnan0@huawei.com Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Diffstat (limited to 'tools/build')
-rw-r--r--tools/build/feature/Makefile8
-rw-r--r--tools/build/feature/test-llvm.cpp8
2 files changed, 16 insertions, 0 deletions
diff --git a/tools/build/feature/Makefile b/tools/build/feature/Makefile
index 8f668bce8996..c09de59affc9 100644
--- a/tools/build/feature/Makefile
+++ b/tools/build/feature/Makefile
@@ -55,6 +55,7 @@ FILES := $(addprefix $(OUTPUT),$(FILES))
CC := $(CROSS_COMPILE)gcc -MD
CXX := $(CROSS_COMPILE)g++ -MD
PKG_CONFIG := $(CROSS_COMPILE)pkg-config
+LLVM_CONFIG ?= llvm-config
all: $(FILES)
@@ -229,6 +230,13 @@ $(OUTPUT)test-cxx.bin:
$(OUTPUT)test-jvmti.bin:
$(BUILD)
+$(OUTPUT)test-llvm.bin:
+ $(BUILDXX) -std=gnu++11 \
+ -I$(shell $(LLVM_CONFIG) --includedir) \
+ -L$(shell $(LLVM_CONFIG) --libdir) \
+ $(shell $(LLVM_CONFIG) --libs Core BPF) \
+ $(shell $(LLVM_CONFIG) --system-libs)
+
-include $(OUTPUT)*.d
###############################
diff --git a/tools/build/feature/test-llvm.cpp b/tools/build/feature/test-llvm.cpp
new file mode 100644
index 000000000000..d8d2cee35345
--- /dev/null
+++ b/tools/build/feature/test-llvm.cpp
@@ -0,0 +1,8 @@
+#include "llvm/Support/ManagedStatic.h"
+#include "llvm/Support/raw_ostream.h"
+int main()
+{
+ llvm::errs() << "Hello World!\n";
+ llvm::llvm_shutdown();
+ return 0;
+}