This requires some small changes in the stdenv, then working around the
weird choice LLVM made to hardcode @rpath in its install name, and then
lets us remove a ton of annoying workaround hacks in many of our Go
packages. With any luck this will mean less hackery going forward.
llvm-config is a tool to output compile and linker flags, when compiling against llvm.
The tool however outputs static library names despite libllvm is build
as shared library on nixos. This was fixed for llvm 3.4, 3.5 and 3.7.
For llvm 3.8 and 3.9 it printed the library extension twice (.so.so).
This was fixed in 4.0 and the patch is backported to 3.8 and 3.9 in
this pull request.
```
$ for i in 34 35 37 38 39; do echo "\nllvm-$i"; nix-shell -p llvmPackages_$i.llvm --run 'llvm-config --libnames'; done
llvm-34
libLLVMInstrumentation.so libLLVMIRReader.so libLLVMAsmParser.so
...
llvm-35
libLLVMLTO.so libLLVMObjCARCOpts.so libLLVMLinker.so libLLVMipo.so
...
llvm-37
libLLVMLTO.so libLLVMObjCARCOpts.so libLLVMLinker.so libLLVMBitWriter.so
...
llvm-38
libLLVM-3.8.1.so
llvm-39
libLLVM-3.9.so
```
fixes #26713
This is in preparation for the LLVM 4 upgrade (which gets more strict
about e.g., return false in xcbuild itself) and also for using xcbuild
more extensively in the Darwin stdenv bootstrap process, which is why I
killed the unnecessary gcc dependency in the toolchain. llvm-cov pretends
to be gcov anyway, so we're fine.
* All projects are available under NCSA license,
other than dragonegg.
* "Runtime" projects are dual-licensed under
both NCSA and MIT:
libc++, libc++abi, compiler-rt
* I don't mention MIT for compiler-rt as
we only build it as part of LLVM.
It's a long build and generally painful to split into smaller commits,
so I apologize for lumping many changes into one commit but this is far
easier.
There are still several outdated parts of the darwin stdenv but these
changes should bring us closer to the goal.
Fixes #18461
- Enable the shared library build on darwin by default to match other
platforms.
- Fix the dylib file's name in the store
- Symlink a versioned name as some tooling expects this.
The hashes for libc++ and libc++abi were wrong.
There was also an incompatibility with nixpkgs on darwin which is now
weakly worked around: the "os_trace" macro changed definition in the OS
X development SDK since version 10.9 as used by nixpkgs. LLVM 3.8 uses
the new version, which I am temporarily replacing with a printf on
darwin as it is only used in one minor location.
vcunat's review:
- let's not switch the default versions of llvm* for now
- the only changes I see is adding python to clang's buildInputs
and using the big so-file as discussed in #12759
(BUILD_SHARED_LIBS -> LLVM_LINK_LLVM_DYLIB)
- in future it will be nice to split libLLVM into a separate output
