On Mon, Aug 14, 2017, at 04:36 PM, Ehsan Akhgari wrote: > > * Performance: We switched from msvc+pgo to clang without pgo and got > > comparable perf. We did have to use an order file (/order: flag to > > link.exe) to get comparable startup perf. > That is very interesting! This is one of the aspects that we have been > worried about a lot. We should probably also think about using /order > as well.
It seems plausible that we could use our existing PGO build steps to capture the proper ordering and then re-link using that as input to /order. We already instrument the order of access of omni.ja entries during that step and use that to produce an optimized omni.ja in the second build pass. > > *Debuggability: Basically works, see blockers of https://crbug.com/636111 > > for in-progress work. link.exe can produce pdbs with clang's codeview debug > > info. > Wow, it looks like things have improved quite a bit on this front since > the last time I looked at this closely. Really impressive work! > > -Z7 and -Zi are aliased to each other in clang-cl, we don't do mspdbsrv) > I think this should be sufficient for Firefox's needs as well. We already build all of our non-PGO Windows builds with -Z7 for compatibility with sccache anyway: https://dxr.mozilla.org/mozilla-central/rev/b95b1638db48fc3d450b95b98da6bcd2f9326d2f/build/mozconfig.cache#137 -Ted _______________________________________________ dev-platform mailing list dev-platform@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-platform
