[PATCH] D116750: [clang][lex] Keep references to `DirectoryLookup` objects up-to-date

Thu Jan 13 07:29:43 PST 2022

carlosgalvezp added a comment.

In D116750#3240680 <https://reviews.llvm.org/D116750#3240680>, @jansvoboda11 wrote:

> In D116750#3240363 <https://reviews.llvm.org/D116750#3240363>, @carlosgalvezp wrote:
>
>> Hi @jansvoboda11 !
>>
>> I believe this commit is the root cause of this issue: https://github.com/llvm/llvm-project/issues/53161
>>
>> Believe it or not, I was (un)lucky enough to run into it. I have bisected the repo and my tests indicate that this commit is the offender. Do you have any obvious idea what could be the problem?
>>
>> I'm suspecting this is the offender, since it's related to `#include_next` which is where I get the error:
>> https://github.com/llvm/llvm-project/commit/8503c688d555014b88849e933bf096035a351586#diff-fb96fa41fef79b66ab53ac1d845ab467defc41c2639e9b0cd60b471b04f898cdR981
>> To summarize, clang cannot find `/usr/include` only if I include exactly 511 directories via `-I`. If I include 510 or 512, then it works fine. I will test if the same happens with smaller powers of two. I have a test script that I can share if you want to test it yourself.
>>
>> EDIT: the same happen when including exactly 255 directories. It does not happen for 127 and below. It does happen for 1023 and above.
>
> Hi, thanks for reporting this. The reproducer script would be helpful. Looking at the code, I don't see anything obviously wrong.

Sure, I attach it do this message. It assumes you run from a place from which you can run `./build/bin/clang`.F21622105: test.py <https://reviews.llvm.org/F21622105>

Let me know if I can provide anything else to help! It might not be this commit in particular, perhaps the problem is in some allocator class merged earlier.

Repository:
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https://reviews.llvm.org/D116750