Open springmeyer opened 7 years ago
Flagging: CMake's interprocedural optimization property does not enable lto on gcc and clang - it only does so for the Intel compiler. I ran into this some time ago since it looks fitting. Something to look out for.
Related: maybe a note or two about how to check cxxflags and ldflags in CMake's generated files would be great for debugging - I think the files are called CMakeFiles/TARGET.dir/{flags.make,link.txt}
.
per https://github.com/mapbox/carmen-cache/issues/117#issuecomment-369051742 also we need to ensure the same clang++ major version is used to compile all binaries and libraries" otherwise you'll see an error like:
LLVM gold plugin has failed to create LTO module:
Invalid value (Producer: 'LLVM5.0.0git-30c4647' Reader: 'LLVM 3.9.1')
node-cpp-skel now enables LTO by default: https://github.com/mapbox/node-cpp-skel/issues/110
It seems that -flto
and -Os
cannot currently be used simultaneously when using the Android NDK: https://github.com/android-ndk/ndk/issues/721.
Getting Link Time optimization working takes certain combinations of modern tools and build settings. It would be great to have some general docs on this so that LTO is demystified and more commonly used.
Doc should cover:
Linux details
AR=/path/to/llvm-ar
RANLIB=/path/to/llvm-ranlib
)-flto
in the CXXFLAGSOS X details
-flto
in the CXXFLAGS and LDFLAGSTroubleshooting:
This error indicates that the linker does not understand the LTO format. This will happen on linux if you've not installed binutils from mason.
Refs https://github.com/mapbox/spatial-algorithms/pull/10