Besides a version bump, the following changes have been made to our
toolchain infrastructure:
- LLVM/Clang is now built with -march=native if the host compiler
supports it. An exception to this is CI, as the toolchain cache is
shared among many different machines there.
- The LLVM tarball is not re-extracted if the hash of the applied
patches doesn't differ.
- The patches have been split up into atomic chunks.
- Port-specific patches have been integrated into the main patches,
which will aid in the work towards self-hosting.
- <sysroot>/usr/local/lib is now appended to the linker's search path by
default.
- --pack-dyn-relocs=relr is appended to the linker command line by
default, meaning ports take advantage of RELR relocations without any
patches or additional compiler flags.
The formatting of LLVM port's package.sh has been bothering me, so I
also indented the arguments to the CMake invocation.
By setting CMAKE_MODULE_PATH in the LLVM initial cache scripts, we can
make the "SerenityOS" CMAKE_SYSTEM_NAME usable in the builds of
compiler-rt, libunwind, libcxxabi and libcxx.
This simplifies some toolchain patches and brings the cross-compiler
patches closer to the Port's patches, and closer to something
upstreamable.
If we want to use clang-tidy on the codebase, we'll need to build
clang-tidy from an LLVM that has been patched and built with Serenity
cross-compilation support.
This commit updates the Clang toolchain's version to 13.0.0, which comes
with better C++20 support and improved handling of new features by
clang-format. Due to the newly enabled `-Bsymbolic-functions` flag, our
Clang binaries will only be 2-4% slower than if we dynamically linked
them, but we save hundreds of megabytes of disk space.
The `BuildClang.sh` script has been reworked to build the entire
toolchain in just three steps: one for the compiler, one for GNU
binutils, and one for the runtime libraries. This reduces the complexity
of the build script, and will allow us to modify the CI configuration to
only rebuild the libraries when our libc headers change.
Most of the compile flags have been moved out to a separate CMake cache
file, similarly to how the Android and Fuchsia toolchains are
implemented within the LLVM repo. This provides a nicer interface than
the heaps of command-line arguments.
We no longer build separate toolchains for each architecture, as the
same Clang binary can compile code for multiple targets.
The horrible mess that `SERENITY_CLANG_ARCH` was, has been removed in
this commit. Clang happily accepts an `i686-pc-serenity` target triple,
which matches what our GCC toolchain accepts.
