Re: perf tools: LIBCLANGLLVM=1 build broken with llvm 7/clang 6

[Yonghong Song]

On 6/18/18 7:31 AM, Arnaldo Carvalho de Melo wrote:
> 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 âstd::unique_ptr<llvm::SmallVectorImpl<char> > perf::getBPFObjectFromModule(llvm::Module*)â:
> > > util/c++/clang.cpp:150:43: error: no matching function for call to âllvm::TargetMachine::addPassesToEmitFile(llvm::legacy::PassManager&, llvm::raw_svector_ostream&, llvm::TargetMachine::CodeGenFileType)â
> > >                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.

The formal patch is here:
https://lkml.org/lkml/2018/6/16/92

> - 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