Hi Wang, Yogong, While reviewing the BTF patches for pahole, I updated llvm/clang to HEAD and then building perf with clang embedded I noticed this, will investigate, posting here to document the regression, maybe this is something you came across in other scenario:
$ make LIBCLANGLLVM=1 -C tools/perf/ <SNIP> CC /tmp/tmp.t53Qo38zci/tests/kmod-path.o util/c++/clang.cpp: In function ‘std::unique_ptr<llvm::SmallVectorImpl<char> > perf::getBPFObjectFromModule(llvm::Module*)’: util/c++/clang.cpp:150:43: error: no matching function for call to ‘llvm::TargetMachine::addPassesToEmitFile(llvm::legacy::PassManager&, llvm::raw_svector_ostream&, llvm::TargetMachine::CodeGenFileType)’ TargetMachine::CGFT_ObjectFile)) { ^ In file included from util/c++/clang.cpp:25:0: /usr/local/include/llvm/Target/TargetMachine.h:254:16: note: candidate: virtual bool llvm::TargetMachine::addPassesToEmitFile(llvm::legacy::PassManagerBase&, llvm::raw_pwrite_stream&, llvm::raw_pwrite_stream*, llvm::TargetMachine::CodeGenFileType, bool, llvm::MachineModuleInfo*) virtual bool addPassesToEmitFile(PassManagerBase &, raw_pwrite_stream &, ^~~~~~~~~~~~~~~~~~~ /usr/local/include/llvm/Target/TargetMachine.h:254:16: note: candidate expects 6 arguments, 3 provided mv: cannot stat '/tmp/tmp.t53Qo38zci/util/c++/.clang.o.tmp': No such file or directory make[7]: *** [/home/acme/git/perf/tools/build/Makefile.build:101: /tmp/tmp.t53Qo38zci/util/c++/clang.o] Error 1 make[6]: *** [/home/acme/git/perf/tools/build/Makefile.build:139: c++] Error 2 make[5]: *** [/home/acme/git/perf/tools/build/Makefile.build:139: util] Error 2 make[5]: *** Waiting for unfinished jobs.... CC /tmp/tmp.t53Qo38zci/tests/thread-map.o - Arnaldo