[llvm-dev] Total response file count limited to 21

[Hans Wennborg via llvm-dev]

It seems reasonable to have an expansion limit, but maybe 20 is too low.

Chris: You say you're relying heavily on nested response files. Do you
have a feel for what would be a reasonable limit that wouldn't
interfere with your use case?

Thanks,
Hans

On Fri, Apr 26, 2019 at 5:37 PM Shoaib Meenai <smeenai at fb.com> wrote:
>
> Actually, sorry, my fix was for the case where you had other arguments beginning with @ that weren't response files, whereas yours has actual response files, so my patch won't help there. CCing Reid and Hans, who did a bunch of the implementation in this area.
>
>
>
> From: llvm-dev <llvm-dev-bounces at lists.llvm.org> on behalf of Shoaib Meenai via llvm-dev <llvm-dev at lists.llvm.org>
> Reply-To: Shoaib Meenai <smeenai at fb.com>
> Date: Friday, April 26, 2019 at 8:34 AM
> To: Chris Glover <chrisglover at google.com>, "llvm-dev at lists.llvm.org" <llvm-dev at lists.llvm.org>
> Subject: Re: [llvm-dev] Total response file count limited to 21
>
>
>
> Hi Chris,
>
>
>
> I fixed this in https://reviews.llvm.org/D60631. If you're using a released version of clang you'll have to wait for 9.0 though.
>
>
>
> Thanks,
>
> Shoaib
>
>
>
> From: llvm-dev <llvm-dev-bounces at lists.llvm.org> on behalf of Chris Glover via llvm-dev <llvm-dev at lists.llvm.org>
> Reply-To: Chris Glover <chrisglover at google.com>
> Date: Friday, April 26, 2019 at 8:13 AM
> To: "llvm-dev at lists.llvm.org" <llvm-dev at lists.llvm.org>
> Subject: [llvm-dev] Total response file count limited to 21
>
>
>
> Hi,
>
>
>
> I recently hit this on a project using a build system that relies heavily on nested response files. We found we could only have 21 response files total before getting errors related to the unexpanded response files. I tracked it down to this code in llvm/lib/Support/CommandLine.cpp
>
>
>
>     // If we have too many response files, leave some unexpanded.  This avoids
>     // crashing on self-referential response files.
>     if (RspFiles++ > 20)
>       return false;
>
>
>
> This seems rather arbitrary and in tests I was able to increase it to 200 reliably, which we could do locally for now, but I feel there must be a better way to handle this by tracking processed response files instead of just bailing like this. Or am I missing something?
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> Thanks!
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>
>
> -- chris