[PATCH] D83652: Merge some of the PCH object support with modular codegen

Mon Jul 20 21:16:30 PDT 2020

dblaikie added a comment.

In D83652#2161924 <https://reviews.llvm.org/D83652#2161924>, @hans wrote:

> In D83652#2159585 <https://reviews.llvm.org/D83652#2159585>, @dblaikie wrote:
>
> > @hans - could you perhaps give me a quick summary of commands I could use to test this feature in Chromium (or anything else you might suggest) on a Linux box? I don't have a Windows machine, or any projects that use PCH. (or if you'd be willing to test this, that'd be great - see if the PCH object file has the same symbols before/after this patch)
>
>
> I tried to do this today, and then realized Chromium's PCH .obj files are basically empty these days. Back when I did D48426 <https://reviews.llvm.org/D48426>, dllexported inline functions were emitted in the pch .obj file, but then Chromium started using /Zc:dllexportInlines- which means we don't dllexport inlines anymore, and even if I remove that flag we've moved to only including libc++ headers in our PCH, and nothing is dllexport there.
>
> After applying and building with your patch, the PCH .obj files look the same.
>
> I also verified that building one of Chromium's test targets succeeds with this patch.

Thanks for checking! So, in summary: This seems to work fine for Chromium, but Chromium isn't really exercising this functionality (only insofar as the functionality is enabled, but essentially a no-op)?

@llunak Would you be able to test this on anything you've got?

Repository:
  rG LLVM Github Monorepo

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  https://reviews.llvm.org/D83652/new/

https://reviews.llvm.org/D83652