Cancel builtin llvm and clang support when LLVM version is less than
3.9.0: following commits uses newer API.
Since Clang/LLVM's API is not guaranteed to be stable, add a
test-llvm-version.cpp feature checker, issue warning if LLVM found in
compiling environment is not tested yet.
Committer Notes:
Testing it:
Environment:
$ cat /etc/fedora-release
Fedora release 25 (Twenty Five)
$ rpm -q llvm-devel clang-devel
llvm-devel-3.8.0-1.fc25.x86_64
clang-devel-3.8.0-2.fc25.x86_64
$
Before:
$ make -k LIBCLANGLLVM=1 O=/tmp/build/perf -C tools/perf install-bin
make: Entering directory '/home/acme/git/linux/tools/perf'
BUILD: Doing 'make -j4' parallel build
Warning: tools/include/uapi/linux/bpf.h differs from kernel
Warning: tools/arch/arm/include/uapi/asm/kvm.h differs from kernel
INSTALL GTK UI
LINK /tmp/build/perf/perf
/tmp/build/perf/libperf.a(libperf-in.o): In function `perf::createCompilerInvocation(llvm::SmallVector<char const*, 16u>, llvm::StringRef&, clang::DiagnosticsEngine&)':
/home/acme/git/linux/tools/perf/util/c++/clang.cpp:56: undefined reference to `clang::tooling::newInvocation(clang::DiagnosticsEngine*, llvm::SmallVector<char const*, 16u> const&)'
/tmp/build/perf/libperf.a(libperf-in.o): In function `perf::getModuleFromSource(llvm::SmallVector<char const*, 16u>, llvm::StringRef, llvm::IntrusiveRefCntPtr<clang::vfs::FileSystem>)':
/home/acme/git/linux/tools/perf/util/c++/clang.cpp:68: undefined reference to `clang::CompilerInstance::CompilerInstance(std::shared_ptr<clang::PCHContainerOperations>, bool)'
/home/acme/git/linux/tools/perf/util/c++/clang.cpp:69: undefined reference to `clang::CompilerInstance::createDiagnostics(clang::DiagnosticConsumer*, bool)'
<SNIP>
After:
Makefile.config:807: No suitable libLLVM found, disabling builtin clang and llvm support. Please install llvm-dev(el) (>= 3.9.0)
Updating the environment to a locally built LLVM 4.0 + clang 3.9 (forgot
to git pull, duh) combo, all works as expected, it is properly detected
and built into the resulting perf binary.
Signed-off-by: Wang Nan <wangnan0@huawei.com>
Reported-and-Tested-by: Arnaldo Carvalho de Melo <acme@redhat.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/20161206072230.7651-1-wangnan0@huawei.com
[ Change the warning message a bit (add 'suitable' and 'builtin'), clarifying it, see committer notes above ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
$(BUILD)
$(OUTPUT)test-llvm.bin:
- $(BUILDXX) -std=gnu++11 \
+ $(BUILDXX) -std=gnu++11 \
-I$(shell $(LLVM_CONFIG) --includedir) \
-L$(shell $(LLVM_CONFIG) --libdir) \
$(shell $(LLVM_CONFIG) --libs Core BPF) \
$(shell $(LLVM_CONFIG) --system-libs)
+$(OUTPUT)test-llvm-version.bin:
+ $(BUILDXX) -std=gnu++11 \
+ -I$(shell $(LLVM_CONFIG) --includedir)
+
$(OUTPUT)test-clang.bin:
- $(BUILDXX) -std=gnu++11 \
+ $(BUILDXX) -std=gnu++11 \
-I$(shell $(LLVM_CONFIG) --includedir) \
-L$(shell $(LLVM_CONFIG) --libdir) \
-Wl,--start-group -lclangBasic -lclangDriver \
--- /dev/null
+#include <cstdio>
+#include "llvm/Config/llvm-config.h"
+
+#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
+#define pass int main() {printf("%x\n", NUM_VERSION); return 0;}
+
+#if NUM_VERSION >= 0x030900
+pass
+#else
+# error This LLVM is not tested yet.
+#endif
#include "llvm/Support/ManagedStatic.h"
#include "llvm/Support/raw_ostream.h"
+#define NUM_VERSION (((LLVM_VERSION_MAJOR) << 16) + (LLVM_VERSION_MINOR << 8) + LLVM_VERSION_PATCH)
+
+#if NUM_VERSION < 0x030900
+# error "LLVM version too low"
+#endif
int main()
{
llvm::errs() << "Hello World!\n";
msg := $(warning No g++ found, disable clang and llvm support. Please install g++)
else
$(call feature_check,llvm)
+ $(call feature_check,llvm-version)
ifneq ($(feature-llvm), 1)
- msg := $(warning No libLLVM found, disable clang and llvm support. Please install llvm-dev)
+ msg := $(warning No suitable libLLVM found, disabling builtin clang and LLVM support. Please install llvm-dev(el) (>= 3.9.0))
else
$(call feature_check,clang)
ifneq ($(feature-clang), 1)
- msg := $(warning No libclang found, disable clang and llvm support. Please install libclang-dev)
+ msg := $(warning No suitable libclang found, disabling builtin clang and LLVM support. Please install libclang-dev(el) (>= 3.9.0))
else
CFLAGS += -DHAVE_LIBCLANGLLVM_SUPPORT
CXXFLAGS += -DHAVE_LIBCLANGLLVM_SUPPORT -I$(shell $(LLVM_CONFIG) --includedir)
USE_CXX = 1
USE_LLVM = 1
USE_CLANG = 1
+ ifneq ($(feature-llvm-version),1)
+ msg := $(warning This version of LLVM is not tested. May cause build errors)
+ endif
endif
endif
endif