Since this isn't actively causing issues (as far as I know), let's give this the same priority as other clang-cl bugs. (If it does cause issues, there are workarounds we can do – this bug here is for longer-term size improvements.)

From the other bug:

vm653-m4 executed https://uberchromegw.corp.google.com/i/tryserver.chromium.win/builders/win_chromium_compile_dbg_ng/builds/197529 recently

its /cygdrive/e/b/build/slave/win/build/src/out/Debug is 34G
where ilk files are 9.1G
and pdb are 6.9G

vm840-m4:/cygdrive/e/b/build/slave/win_clang/build/src/out is 31G as of now.


So not necessarily larger at all (as long as we don't switch to lld and back, which apparently is bad for ilk file size)

That's not an apple-to-apple comparison. ilk and pdb files were removed from clang build dir, and after that it took 31G. Before removal it was 102G.

Non-clang build dirs were not cleaned up.

We don't think this is an issue. The main difference is how we do debug info, and the bots build with symbol_level=1.