The reason for this change is that CMake/vcpkg are unable to detect a
change to VCPKG_LIBRARY_LINKAGE. So when we switch to dynamic builds,
the switch would be non-functional, and every developer would have to
remove their Build and vcpkg cache directories manually. By changing
these directories, vcpkg is able to detect it must rebuild.
LLVM recommends compiling with at least -O1 to have decent performance
with sanitizers enabled. Indeed, this improves CI performance of LibWeb
tests as follows:
GCC on Linux: 160.61s to 119.68s (40.93s faster)
Clang on Linux: 65.56s to 55.64s ( 9.92s faster)
AK will depend on some vcpkg dependencies, so the Lagom tools build will
need to know how to use vcpkg. We can do this by sym-linking vcpkg.json
to Meta/Lagom (as vcpkg.json has to be in the CMake source directory).
We also need a CMakePresets.json in the source directory, which can just
include the root file. The root CMakePresets then needs to define paths
relative to ${fileDir} rather than ${sourceDir}.
We currently build debug and release versions of vcpkg dependencies. We
will most commonly only need the release version, so let's default to
that to approximately halve our dependency build time.
This changes the Sanitizer configs to build all the vcpkg dependencies
with our specified CFLAGS and CXXFLAGS for ASAN and UBSAN.
Unfortunately, we can't yet enable actually compiling them with
sanitizers enabled, because this causes test failures that need to be
investigated.
By default, we were linking the debug version of all vcpkg dependencies,
which was very noticeable in benchmarks. Let's default to a build type
with reasonable performance.
