[llvm-dev] can't build/run after adding lib to Fibonacci example, even reverting the complete llvm tree does not help

[Dennis Luehring via llvm-dev]

>No idea either why it re-reruns, but it should not be that much of an
>issue and not re-run when you rebuild without changes to CMakeLists.

i' will your other suggestions (with starting VStudio from commandline with VCVars set) if that helps

>The debug version of tablegen is quite slow. You can either set
>LLVM_TABLEGEN/CLANG_TABLEGEN to separately compiled release version of
>them or use LLVM_OPTIMIZED_TABLEGEN which does that for you.

i'll give that a try

>You may want to restrict the number of parallel project builds:
>Options->Projects and Solutions->Build and Run->maximum number of
>parallel build jobs

hope the build time will not raise again by a large margine using just 1 of my cores

thx

Am 24.09.2018 um 07:27 schrieb Michael Kruse:
> Am Sa., 22. Sep. 2018 um 00:12 Uhr schrieb Dennis Luehring via
> llvm-dev <llvm-dev at lists.llvm.org>:
> >
> > first: thank you for helping out
> >
> >  >I might try compiling your source from the VS's Developer Command Prompt:
> >  >cmake --build . --target Fibonacci
> >  >Does this work?
> >
> > call "C:\Program Files (x86)\Microsoft Visual
> > Studio\2017\Community\VC\Auxiliary\Build\vcvars64.bat"
> > cd llvm-build
> > cmake --build . --config Debug --target Fibonacci
> >
> > building Fibonacci example works BUT X86CommonTableGen get rebuild again?
> >
> > Das Projekt
> > "D:\projects\fun\jit_tests\clang_from_src\llvm-build\lib\Target\X86\InstPrinter\LLVMX86AsmPrinter.vcxproj"
> > (37) erstellt
> > "D:\projects\fun\jit_tests\clang_from_src\llvm-build\lib\Target\X86\X86CommonTableGen.vcxproj"
> > (38) auf Knoten "1" (Standardziele).
> > InitializeBuildStatus:
> > "x64\Debug\X86CommonTableGen\X86Commo.1917F16D.tlog\unsuccessfulbuild"
> > wird erstellt, da "AlwaysCreate" angegeben wurde.
> > CustomBuild:
> >    Building X86GenAsmMatcher.inc...
> >    Building X86GenAsmWriter.inc...
> >    Building X86GenAsmWriter1.inc...
> >    Building X86GenCallingConv.inc...
> >    Building X86GenDAGISel.inc...
> >    Building X86GenDisassemblerTables.inc...
> >    Building X86GenEVEX2VEXTables.inc...
> >    Building X86GenFastISel.inc...
> >    Building X86GenGlobalISel.inc...
> >    ...
> > which costs me much time (>30min) on my slow system - and i don't
> > understand why "AlwaysCreate" is used here - i only added one lib
> > dependencie to an example and reverted it? now the totaly unrelated big
> > one is build again
> > it could be that faster systems do not suffer that much from this
> > behavior but it still does not feel right
> >
> > enough RAM, no swapping, just my 2 core CPU is not fast enough
>
> No idea either why it re-reruns, but it should not be that much of an
> issue and not re-run when you rebuild without changes to CMakeLists.
> The debug version of tablegen is quite slow. You can either set
> LLVM_TABLEGEN/CLANG_TABLEGEN to separately compiled release version of
> them or use LLVM_OPTIMIZED_TABLEGEN which does that for you.
>
>
>
> > result: Fibonacci was built without errors
> >
> > after building i reopened llvm-build\LLVM.sln in VS2017 ... loading 273
> > projects
> > and tested what happend on selecting "build solution" - to check what
> > else happened to build now
> > serveral cpp getting compiled, libs/exes getting linked - i think that
> > is related to the X86CommonTableGen rebuild
> > another >30min waiting to "finish building" the solution inside of the IDE
> >
> > nearly enough RAM, started swapping on building lli.cpp :(, but get back
> > to under 5GB Ram usage after some seconds, my 2 core CPU is still not
> > fast enough
>
> You may want to restrict the number of parallel project builds:
> Options->Projects and Solutions->Build and Run->maximum number of
> parallel build jobs
>
> Michael