[PATCH] D20993: [lit] Add support for PGO profile and code coverage collection

[Matthias Braun via llvm-commits]

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MatzeB added a comment.

This adds a bigger bunch of code to lit, I wonder if it is necessary:

- I assume the necessity for the logic inside lit is just the fact that the profile data overwrites each other after running a command. Is setting LLVM_PROFILE_FILE with a '%p' placeholder not enough to avoid this? The final profile data merging can always be done outside of llvm-lit afterwards. Or are there other reasons why you need to intercept the opt/llc/etc. calls?

- The lit tests don't strike me as the most typical llvm usage (they are often designed to test corner cases of the compiler), wouldn't it be better to gather profiles by compiling the llvm test-suite or something similar?


http://reviews.llvm.org/D20993