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romange / helio

A modern framework for backend development based on io_uring Linux interface
Apache License 2.0
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make helio compile on macOS #96

Closed yuelimv closed 1 year ago

yuelimv commented 1 year ago

This patch uses libcares installed by homebrew on macOS instead. The previous libcares built from the original source seems have extra dependencies on -lresolv when helio is built on a mac, which seems to unnecessary.

CMakeLists.txt is modified to turn off libunwind. An alternative way is to pass a flag to blaze.sh or cmake inside blaze.sh, for instance:

./blaze.sh -ninja -release -DWITH_UNWIND=OFF

Furthermore, we need to avoid linking against librt on macOS. This has just been done in another PR

https://github.com/romange/helio/pull/97

Tested on macOS Big Sur 11.7.7

> g++ -v
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/4.2.1
Apple clang version 12.0.5 (clang-1205.0.22.11)
Target: x86_64-apple-darwin20.6.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
> gcc -v
Configured with: --prefix=/Applications/Xcode.app/Contents/Developer/usr --with-gxx-include-dir=/Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX.sdk/usr/include/c++/4.2.1
Apple clang version 12.0.5 (clang-1205.0.22.11)
Target: x86_64-apple-darwin20.6.0
Thread model: posix
InstalledDir: /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin
chakaz commented 1 year ago

Hi @yuelimv, thanks for your contribution! I'm not sure that I follow - why not download and compile cares as a static library? It doesn't compile? Maybe we can patch its makefile somehow, like we do for other archs?

Re/ libunwind - I never really used macos, but I read online that it's possible to install, perhaps we could better detect that somehow instead of always disabling it?

yuelimv commented 1 year ago

hi @chakaz

Hi @yuelimv, thanks for your contribution! I'm not sure that I follow - why not download and compile cares as a static library? It doesn't compile? Maybe we can patch its makefile somehow, like we do for other archs?

Without this patch, the current implementation download a copy of libcares, build it. But for some reason, the one built on mac always asks for libresolv as part of the dependencies, which I couldn't find the way to install. This will need further investigation to see how the library can be configured not to require such dependency.

Re/ libunwind - I never really used macos, but I read online that it's possible to install, perhaps we could better detect that somehow instead of always disabling it?

Yes that is possible... Apple has a proprietary version that ships together with macOS... for instance, I can find it under /opt/local/lib, and it might also be possible to install a copy through mac ports. At least manually editing build.ninja to use the correct library path will make it work. But I felt doing so might require some more changes to cmake files comparing to this change.

Could you explain the benefit of keeping libunwind on macOS? I actually don't quite understand its full purpose. But according to @romange libunwind current introduces bugs that slows down exception handling... it was turned off in release mode for dragonfly

From what I googled, vanilla libunwind seems does not have macOS support according to discussions on their mailing list. As a matter of fact, I couldn't make it compile on macos.

romange commented 1 year ago

Hi @chakaz - I've been discussing about this change with @yuelimv offline. I do not consider libunwind as a required feature. We use it only for improving the quality of CPU profiling. Regarding libcares - I think it's fine to use the distribution library: libcares is mature enough and for now we want to get something simple that works, and using a system lib seems to fit the profle :)