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

[Yonghong Song <yhs@fb.com>]

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 ‘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.

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
>>>