On Mon, Sep 9, 2019 at 5:37 PM Sylvestre Ledru <sylves...@debian.org> wrote: > > Hello, > > Le 30/08/2019 à 18:38, Hans Wennborg via Release-testers a écrit : > > Hello everyone, > > > > 9.0.0-rc3 was tagged today from the release_90 branch at r370450. In > > the Git monorepo, it's tagged as llvmorg-9.0.0-rc3. > I experienced an issue with lto. Initially not clang related but might be. > > For a few months, I have been building packages using ThinLTO ( > -DLLVM_ENABLE_LTO="Thin" ) and stage2. gcc for stage1. > > Debian unstable and the next Ubuntu updated to gcc-9. This version is stricter > on -flto (only accept understood values ([1]). > It caused the build to fail on polly with "No ffs implementation found" > (which is just > cmake failing with -flto=thin) [2] > This clearly makes sense. > So, I tried to use -DBOOTSTRAP_LLVM_ENABLE_LTO="Thin" to have only -flto=Thin > used in the stage2. > > However, this caused two issues: > * Some packages became much bigger (21M => 141M) > * Linking failed for some packages with: > /usr/bin/ld: /usr/lib/llvm-9/lib/libclangCodeGen.a: error adding symbols: > archive has no index; run ranlib to > one [3] > > I tried to play with clang cmake file [4] but I haven't been able to fix it. > > For now, I am forcing the usage of gcc-8 but this won't scale. > > Anyway, probably not a blocker for the 9 release but I prefer to report this > in case other are getting this issue.
Thanks for raising it. I've never used our cmake files to bootstrap directly. Does it work if you do the steps manually: first invoke cmake and do a regular build with gcc 9, then invoke cmake separately for the second build, setting the flags to use the clang and lld from the first step, with thinlto? _______________________________________________ lldb-dev mailing list lldb-dev@lists.llvm.org https://lists.llvm.org/cgi-bin/mailman/listinfo/lldb-dev
