This option sets -fprofile-instr-generate -fcoverage-mapping for Clang
builds only on almost all of Userland. Loader and LibTimeZone are
exempt. This can be used for generating code coverage reports, or even
PGO in the future.
With this change, System::foo() becomes Core::System::foo().
Since LibCore builds on other systems than SerenityOS, we now have to
make sure that wrappers work with just a standard C library underneath.
This is a hack to avoid a circular dependency issue with the stack check
failure handler being in LibC.
This is not ideal, and there's most likely a better way to solve this.
That said, LibSystem should not have anything but thin wrappers around
system calls, so stack protectors have limited utility here anyway.
Previously, libc.a contained undefined symbols from ssp and libsystem,
which caused static compilation to fail.
We now generate libc.a with a custom CMake rule that combines all
object files from libc, ssp and libsystem to form libc.a
Closes#5758.
This achieves two things:
- Programs can now intentionally perform arbitrary syscalls by calling
syscall(). This allows us to work on things like syscall fuzzing.
- It restricts the ability of userspace to make syscalls to a single
4KB page of code. In order to call the kernel directly, an attacker
must now locate this page and call through it.
