[PATCH] D57009: [llvm-objcopy] [COFF] Fix handling of aux symbols for big objects

Wed Jan 23 01:51:06 PST 2019

jhenderson added a comment.

In D57009#1367437 <https://reviews.llvm.org/D57009#1367437>, @mstorsjo wrote:

> In D57009#1366076 <https://reviews.llvm.org/D57009#1366076>, @jhenderson wrote:
>
> > > Other llvm-objcopy reviewers: I'd like to add a custom hidden option for testing, for triggering using the big object format. Without that, a test would have to create over 32k sections to trigger that.
> >
> > I'm not a fan of adding hidden options purely for testing when there are alternatives. In the ELF tests, we use a pre-built zip file containing an object with many sections (see ELF/many-sections.test). I think you could probably do the same thing here.
>
>
> I'm experimenting with crafting such an input file now. The uncompressed object file weighs in at around 5 MB, and after gzip (as is used for that ELF test) it currently ends up at around 725 KB. Do you think that's acceptable or too large?

It's not ideal, if I'm honest, but it might be a quirk of the file format, and therefore unavoidable. The equivalent file for ELF is only 152 KB. I don't know if it was somehow more aggressively compressed though. If you can't get it any smaller, I think it's probably acceptable.

By the way, there's a gunzip.py script in the ELF/Inputs directory, which you should probably move to a shared area and use for decompressing.

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