[cfe-dev] [llvm-dev] Windows /bigobj

Aaron Ballman via cfe-dev cfe-dev at lists.llvm.org
Mon Dec 17 07:50:51 PST 2018


On Mon, Dec 17, 2018 at 10:48 AM Gábor Márton <martongabesz at gmail.com> wrote:
> Hi Aaron, thanks for your answer.
>
> > We usually try to limit it in cases where it makes sense to do so.
> e.g., for a while we would put in efforts to reduce the number of
> template instantiations to help avoid this problem. However, I believe
> we only do that up to a point.
>
> The corresponding file is a unittest file "ASTImporterTest.cpp" with many gtest macros, which I suspect do quite many template instantiations.
> I don't think it would be easy to reduce the size in this case, but I am open to any idea.
> Is it okay to connect with the buildbot owner and ask for /bigobj for this file? Who should approve such decisions?

This is done on a file-by-file basis rather than a bot-by-bot basis.
Simon made the recommended changes in r349357 by updating the CMake
file to properly add the flag to just ASTImporterTest.cpp, so
everything should be in a good state now.

~Aaron

>
> Thanks,
> Gabor
>
>
> On Mon, Dec 17, 2018 at 4:18 PM Aaron Ballman <aaron at aaronballman.com> wrote:
>>
>> On Mon, Dec 17, 2018 at 10:12 AM Gábor Márton via llvm-dev
>> <llvm-dev at lists.llvm.org> wrote:
>> >
>> > Hi,
>> >
>> > Recently one Windows build bot failed by my commit, because the obj file being generated is too big:
>> >
>> > C:\ps4-buildslave2\llvm-clang-x86_64-expensive-checks-win\llvm\tools\clang\unittests\AST\ASTImporterTest.cpp : fatal error C1128: number of sections exceeded object file format limit: compile with /bigobj
>> >
>> > Is there an LLVM policy to limit the maximum size of the generated obj files?
>>
>> We usually try to limit it in cases where it makes sense to do so.
>> e.g., for a while we would put in efforts to reduce the number of
>> template instantiations to help avoid this problem. However, I believe
>> we only do that up to a point.
>>
>> > If not then I suspect the only solution is to turn on /bigobj on the build bot, right?
>>
>> We already required that for some files; we turn on /bigobj support
>> for several files in Clang. We usually only do this on a file-by-file
>> basis though, so we can be alerted when new files are causing
>> problems.
>>
>> ~Aaron
>>
>> > (Of course, I could refactor the cpp file to several smaller ones, but how do I know where to cut it?)
>> >
>> > Thanks,
>> > Gabor
>> > _______________________________________________
>> > LLVM Developers mailing list
>> > llvm-dev at lists.llvm.org
>> > http://lists.llvm.org/cgi-bin/mailman/listinfo/llvm-dev


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