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Date:   Mon, 18 Jun 2018 11:31:39 -0300
From:   Arnaldo Carvalho de Melo <acme@kernel.org>
To:     Yonghong Song <yhs@fb.com>
Cc:     Wang Nan <wangnan0@huawei.com>, Jiri Olsa <jolsa@kernel.org>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        Alexei Starovoitov <ast@fb.com>,
        Martin KaFai Lau <kafai@fb.com>,
        Daniel Borkmann <daniel@iogearbox.net>
Subject: Re: perf tools: LIBCLANGLLVM=1 build broken with llvm 7/clang 6
Message-ID: <20180618143139.GA20477@kernel.org>
References: <20180616122608.GM30043@kernel.org>
 <91a76633-54e4-984d-cb68-ca0445146b15@fb.com>
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Em Sat, Jun 16, 2018 at 10:20:21AM -0700, Yonghong Song escreveu:
> 
> 
> On 6/16/18 5:26 AM, Arnaldo Carvalho de Melo wrote:
> > 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
> 
> There is an interface change in llvm 7.0 (trunk) for function
> llvm::TargetMachine::addPassesToEmitFile. The following patch
> should fix the problem.

Please submit it, I just tested and the the build finishes Ok.

- Arnaldo
 
> -bash-4.2$ git diff
> diff --git a/tools/perf/util/c++/clang.cpp b/tools/perf/util/c++/clang.cpp
> index bf31cea..11dee58 100644
> --- a/tools/perf/util/c++/clang.cpp
> +++ b/tools/perf/util/c++/clang.cpp
> @@ -146,8 +146,15 @@ getBPFObjectFromModule(llvm::Module *Module)
>         raw_svector_ostream ostream(*Buffer);
> 
>         legacy::PassManager PM;
> -       if (TargetMachine->addPassesToEmitFile(PM, ostream,
> - TargetMachine::CGFT_ObjectFile)) {
> +       bool NotAdded;
> +#if CLANG_VERSION_MAJOR < 7
> +       NotAdded = TargetMachine->addPassesToEmitFile(PM, ostream,
> + TargetMachine::CGFT_ObjectFile);
> +#else
> +       NotAdded = TargetMachine->addPassesToEmitFile(PM, ostream, nullptr,
> + TargetMachine::CGFT_ObjectFile);
> +#endif
> +       if (!NotAdded) {
>                 llvm::errs() << "TargetMachine can't emit a file of this
> type\n";
>                 return
> std::unique_ptr<llvm::SmallVectorImpl<char>>(nullptr);;
>         }
> -bash-4.2$
> 
> Will submit a formal patch soon.
> 
> > 
> > - Arnaldo
> >