[PATCH] D27790: Pass sample pgo flags to thinlto.

[Teresa Johnson via Phabricator via llvm-commits]

tejohnson accepted this revision.
tejohnson added inline comments.


================
Comment at: lib/LTO/LTO.cpp:135
+    if (FileOrErr)
+      Hasher.update(FileOrErr.get()->getBuffer());
+  }
----------------
mehdi_amini wrote:
> tejohnson wrote:
> > Will this be expensive, for large apps with large profiles? Since this is the same for each backend, can we compute once and pass down?
> If we go this route (and we should), then I rather do it as a separate patch and do as I suggested originally when the config was added there: have a `hash` method on the config itself where we would hash early the whole config part and do it once early.
Agreed, all the module-independent stuff should be hashed early and passed down. I suppose this is the best approach for now - maybe slow, but safe and enables this change to go in.

We can pull it out as part of the config early hashing implementation in a separate patch.


https://reviews.llvm.org/D27790