Closed Bug 1632542 Opened 3 months ago Closed 3 months ago

Regenerate linker order files, April 2020 edition


(Firefox Build System :: General, enhancement)



(firefox77 fixed)

Tracking Status
firefox77 --- fixed


(Reporter: dmajor, Assigned: dmajor)




(1 file)

No description provided.

The original commit message for the order files says "It's OK if these files are slightly out of date", and that's true. However, in the 11 months since then, our builds have undergone major changes that affect large numbers of final symbol names, like switching from Frontend to IR PGO, and enabling the new pass manager. I think at this point a refresh wouldn't hurt.

I generated these files by locally creating a "stage 2.5" PGO build that's both -fprofile-use and -finstrument-functions-after-inlining, and otherwise following the instructions from bug 1444171. Doing this at the use stage rather than the gen stage lets us get around the problem of mixing IR and Frontend instrumentation. It also gets us a more accurate picture of the final optimizations.

I haven't exhaustively run this through Talos. I did some spot checks, most were within noise, Speedometer maaybe gets 0.6%. I don't think this is worth hogging the talos machines for a full run, we can get the results after landing.

If for no other reason, this is worth doing to reduce 8000 lines of warning LNK4037 (order file refers to a nonexistent symbol) in build logs down to about 150.

Pushed by
Regenerate linker order files, April 2020 edition r=rstewart
Closed: 3 months ago
Resolution: --- → FIXED
Target Milestone: --- → mozilla77
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