I’ve linked a prebuilt object that defines `__cyg_profile_func_enter` and `__cyg_profile_func_exit` using LDFLAGS, and that got rid of the initial linker errors. Huzzah!
However, now I’m facing other more concerning linker errors: https://gist.github.com/victorporof/55490f49c7b13b4bcfae10ca4f0c169c Here’s what I did: 1. Built this simple trace.cpp: https://gist.github.com/victorporof/e9809e33c4dc67ef388672791c4c80cd - Used `clang++ trace.cpp -mmacosx-version-min=10.9 -c -o trace.o` - I’m building this without `-finstrument-functions`, obviously. 2. Added the following to my mozconfig: CFLAGS="-finstrument-functions" CXXFLAGS="-finstrument-functions" LDFLAGS="-L[path/to/object] -ltrace.o” 3. `./mach build` Linker errors galore! Anything I’m doing wrong? Victor > On 10. Nov 2018, at 15:50, David Major <dma...@mozilla.com> wrote: > > I think you'll have a tough time trying to build any binaries that are > by nature incomplete without an LD_PRELOAD. You'll have better luck if > you either properly link your __cyg_profile implementations during the > build, or link against stubs that you then override with LD_PRELOAD. > > Our Windows PGO builds currently use the -finstrument... family in > order to log function call order. You could probably adapt this by > removing the WINNT and MOZ_PGO conditions from > https://searchfox.org/mozilla-central/rev/a3894a4dcfb5d42f2e6eee6cb9faf7141879ef1a/python/mozbuild/mozbuild/frontend/emitter.py#1120 > and > https://searchfox.org/mozilla-central/rev/a3894a4dcfb5d42f2e6eee6cb9faf7141879ef1a/mozglue/build/moz.build#41 > . > > The limitation of that implementation is that its only instruments > libxul. This was our way of getting the most bang per buck and > sidestepping having to deal with all the miscellaneous binaries with > idiosyncratic build requirements. > > Also, if you wait a couple days, I'm sure someone who actually knows > what they're doing will chime in with a better solution than mine. :) > > On Sat, Nov 10, 2018 at 8:57 AM Victor Porof <vpo...@mozilla.com> wrote: >> >> Hey folks, >> >> I’m trying to build Firefox Desktop with `-finstrument-functions`. End goal >> is doing some exploratory tracing as part of upcoming browser-architecture >> efforts. >> >> What’s the appropriate way of doing this? >> >> I tried doing the most naive thing of just passing that flag through CFLAGS >> and CXXFLAGS with the intention of later linking something like >> liblttng-ust-cyg-profile via LD_PRELOAD that defines >> `__cyg_profile_func_enter` and `__cyg_profile_func_exit`. However, `mach >> build` then results in >> https://gist.github.com/victorporof/ef17b57b19aa9fdb5a9a3a30eecde2ea (of >> course). >> >> Any hints? >> Victor >> >> _______________________________________________ >> dev-builds mailing list >> dev-builds@lists.mozilla.org >> https://lists.mozilla.org/listinfo/dev-builds _______________________________________________ dev-builds mailing list dev-builds@lists.mozilla.org https://lists.mozilla.org/listinfo/dev-builds
