[llvm-dev] Windows/Clang build instrumented/PGO

Sat Feb 23 03:55:04 PST 2019

I would be really interested in this as I've been thinking of doing
PGO builds of lld for windows (based on a profile of linking our
binaries). Tobias, did you advance?

On Thu, Jan 24, 2019 at 10:45 PM David Major via llvm-dev
<llvm-dev at lists.llvm.org> wrote:
>
> I don't think there's any reason that it would be fundamentally
> impossible, but it could very well be that you are the first person to
> attempt it and have discovered some bugs standing in the way.
>
> Two issues that I'm seeing in the log:
>
> * lld-link.exe is being given compiler flags (-fuse-ld, -fprofile...).
> There could be a mixup between C flags and linker flags somewhere.
>
> * The missing symbols happen because clang_rt.profile-$ARCH.lib was
> not included on lld-link's command line.
>
> I'm afraid I don't know LLVM's build system well enough to say how to
> address these, but hopefully it's a start.
>
> On Wed, Jan 23, 2019 at 2:54 PM Tobias Hieta via llvm-dev
> <llvm-dev at lists.llvm.org> wrote:
> >
> > Hello LLVM developers,
> >
> > Following some hints on this mailing list earlier this year on how to make clang faster than stock llvm.org builds I have implemented a script that builds a PGO optimized version of clang by following the guide here: http://llvm.org/docs/HowToBuildWithPGO.html
> >
> > This works great on macOS and Linux - we gained almost 15% in our project with this technique. I am now looking at doing this on Windows and I am running into problems.
> >
> > I bootstrap the build by downloading the 7.0.1 binaries from llvm.org, then pass clang-cl as the compiler and lld-link as the linker. I have Visual Studio 2015 CE installed as well and run all the commands under a cmd that has the right vcvars set.
> >
> > To build the instrumented build I pass -DLLVM_BUILD_INSTRUMENTED=ON, I started with passing -DLLVM_BUILD_INSTRUMENTED=IR but that doesn't build because clang-cl doesn't understand the flags passed then. Instrumeted=ON makes it build but it fails to link ( see build log at the end of the email ).
> >
> > Has anyone managed to build a PGO version of clang on windows? Is there something in my configuration that is wrong for this setup? Or is this build configuration not supported at all?
> >
> > Thanks for the help,
> > Tobias
> >
> > [285/1938] Linking CXX executable bin\llvm-tblgen.exe
> > FAILED: bin/llvm-tblgen.exe
> > cmd.exe /C "cd . && C:\.conan\6785u87h\1\bin\cmake.exe -E vs_link_exe --intdir=utils\TableGen\CMakeFiles\llvm-tblgen.dir --manifests  -- C:\code\clang-builder\src\bootstrap\bin\lld-link.exe /nologo utils\TableGen\CMakeFiles\llvm-tblgen.dir\AsmMatcherEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\AsmWriterEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\AsmWriterInst.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\Attributes.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CallingConvEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeEmitterGen.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeGenDAGPatterns.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeGenHwModes.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeGenInstruction.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeGenMapTable.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeGenRegisters.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeGenSchedule.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeGenTarget.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\DAGISelEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\DAGISelMatcherEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\DAGISelMatcherGen.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\DAGISelMatcherOpt.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\DAGISelMatcher.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\DFAPacketizerEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\DisassemblerEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\FastISelEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\FixedLenDecoderEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\GlobalISelEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\InfoByHwMode.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\InstrInfoEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\InstrDocsEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\IntrinsicEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\OptParserEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\PredicateExpander.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\PseudoLoweringEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\RISCVCompressInstEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\RegisterBankEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\RegisterInfoEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\SDNodeProperties.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\SearchableTableEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\SubtargetEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\SubtargetFeatureInfo.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\TableGen.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\Types.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\X86DisassemblerTables.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\X86EVEX2VEXTablesEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\X86FoldTablesEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\X86ModRMFilters.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\X86RecognizableInstr.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\WebAssemblyDisassemblerEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CTagsEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\__\__\resources\windows_version_resource.rc.res  /out:bin\llvm-tblgen.exe /implib:lib\llvm-tblgen.lib /pdb:bin\llvm-tblgen.pdb /version:0.0  /machine:x64 -fuse-ld=lld /STACK:10000000 -fprofile-instr-generate='C:\code\clang-builder\build\instrumented\profiles\%4m.profraw' /INCREMENTAL:NO /subsystem:console  lib\LLVMSupport.lib lib\LLVMTableGen.lib lib\LLVMSupport.lib psapi.lib shell32.lib ole32.lib uuid.lib advapi32.lib lib\LLVMDemangle.lib kernel32.lib user32.lib gdi32.lib winspool.lib shell32.lib ole32.lib oleaut32.lib uuid.lib comdlg32.lib advapi32.lib && cmd.exe /C "cd /D C:\code\clang-builder\build\instrumented\utils\TableGen && CMAKE_OBJCOPY-NOTFOUND --only-keep-debug C:/code/clang-builder/build/instrumented/bin/llvm-tblgen.exe C:/code/clang-builder/build/instrumented/bin/llvm-tblgen.exe.debug && CMAKE_STRIP-NOTFOUND -gx C:/code/clang-builder/build/instrumented/bin/llvm-tblgen.exe -R .gnu_debuglink && CMAKE_OBJCOPY-NOTFOUND --add-gnu-debuglink=C:/code/clang-builder/build/instrumented/bin/llvm-tblgen.exe.debug C:/code/clang-builder/build/instrumented/bin/llvm-tblgen.exe""
> > LINK: command "C:\code\clang-builder\src\bootstrap\bin\lld-link.exe /nologo utils\TableGen\CMakeFiles\llvm-tblgen.dir\AsmMatcherEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\AsmWriterEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\AsmWriterInst.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\Attributes.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CallingConvEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeEmitterGen.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeGenDAGPatterns.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeGenHwModes.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeGenInstruction.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeGenMapTable.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeGenRegisters.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeGenSchedule.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CodeGenTarget.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\DAGISelEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\DAGISelMatcherEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\DAGISelMatcherGen.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\DAGISelMatcherOpt.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\DAGISelMatcher.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\DFAPacketizerEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\DisassemblerEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\FastISelEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\FixedLenDecoderEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\GlobalISelEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\InfoByHwMode.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\InstrInfoEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\InstrDocsEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\IntrinsicEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\OptParserEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\PredicateExpander.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\PseudoLoweringEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\RISCVCompressInstEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\RegisterBankEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\RegisterInfoEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\SDNodeProperties.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\SearchableTableEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\SubtargetEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\SubtargetFeatureInfo.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\TableGen.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\Types.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\X86DisassemblerTables.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\X86EVEX2VEXTablesEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\X86FoldTablesEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\X86ModRMFilters.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\X86RecognizableInstr.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\WebAssemblyDisassemblerEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\CTagsEmitter.cpp.obj utils\TableGen\CMakeFiles\llvm-tblgen.dir\__\__\resources\windows_version_resource.rc.res /out:bin\llvm-tblgen.exe /implib:lib\llvm-tblgen.lib /pdb:bin\llvm-tblgen.pdb /version:0.0 /machine:x64 -fuse-ld=lld /STACK:10000000 -fprofile-instr-generate='C:\code\clang-builder\build\instrumented\profiles\%4m.profraw' /INCREMENTAL:NO /subsystem:console lib\LLVMSupport.lib lib\LLVMTableGen.lib lib\LLVMSupport.lib psapi.lib shell32.lib ole32.lib uuid.lib advapi32.lib lib\LLVMDemangle.lib kernel32.lib user32.lib gdi32.lib winspool.lib shell32.lib ole32.lib oleaut32.lib uuid.lib comdlg32.lib advapi32.lib /MANIFEST /MANIFESTFILE:bin\llvm-tblgen.exe.manifest" failed (exit code 1) with the following output:
> > lld-link.exe: warning: ignoring unknown argument: -fuse-ld=lld
> > lld-link.exe: warning: ignoring unknown argument: -fprofile-instr-generate='C:\code\clang-builder\build\instrumented\profiles\%4m.profraw'
> > lld-link.exe: error: undefined symbol: __llvm_profile_runtime
> > >>> referenced by utils\TableGen\CMakeFiles\llvm-tblgen.dir\AsmMatcherEmitter.cpp.obj:(__llvm_profile_runtime_user)
> >
> >
> > lld-link.exe: error: undefined symbol: __llvm_profile_register_function
> > >>> referenced by utils\TableGen\CMakeFiles\llvm-tblgen.dir\AsmMatcherEmitter.cpp.obj:(__llvm_profile_register_functions)
> > >>> referenced by utils\TableGen\CMakeFiles\llvm-tblgen.dir\AsmMatcherEmitter.cpp.obj:(__llvm_profile_register_functions)
> >
> > _______________________________________________
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-- 

Leonardo Santagada