[cfe-dev] Proposal: add instrumentation for PGO and code coverage

[Eric Christopher]

> Also, to the point of only having one data file per executable, it seems like it would be better to associate a data file per source file. That way I can more easily store my profile data along with my source file and it will get used individually when that source file gets pulled into different builds.
>

This is probably not workable. Think about the LTO case when you want
to merge compile units. What profile data goes with the particular
file will depend on the executable that's created. Also the workload
profile for a given translation unit could vary quite significantly
depending on workflow.

-eric