When executing a non-inlined syscall, we spill all static registers.
We weren't storing in to the thread context that we have done this.
If a signal occured between FEX returning from the syscall (after the
blr) and before the `FillStaticRegs` then the signal handler would get
the incorrect register state.
This typically manifested as Steam getting a SIGCHLD, trying to recover
the guest stack pointer, and it that pointer would be zero or some other
corrupt value. Thus crashing inside of the signal handler.
Surprising that we hadn't hit this way more before this point, must have
needed hardware that tickled the race condition *just* right.
This has been a long time coming. The C interface has been a thorn in
our side for no reason for a long time.
The purpose of this step is to remove the C interface without changing
behaviour as much as possible. This means that with this commit there
are still some bad practices but the remaining issues will be solved
with followup PRs.
Primarily, we still have a `DestroyContext(CTX)` static function which calls
the Context implementation's `DestroyContext` and does a raw C++ delete.
Follow up PR will remove that, but I didn't want to touch it yet since
it'll require checking to ensure the unique_ptr changes play nice with
our allocator hooking. Which this is already a huge PR without trying to
change behaviour.
Take a leaf from the Vector ops and have the jump entry choose the IR
op.
Also generate one atomic op and modify the IR type in the locked memory
type just like the non locked memory path.
This class of instructions in the number one instruction type percentage
wise, so making this more optimal will be a win.
It's a fairly minor optimization so it should be a small impact.
We can move the initial move down by SPLICE, which not only lets us turn
it into a MOVPRFX, but also we can safely move into the final
destination register directly, since we can be sure there's no
potential dependencies at this point
Fixes#2410
We were pulling the guest RSP before spilling static registers back to
the state.
Move this to after we spill SRA state to fix this bug.
Thanks to @ifquant for diving in, identifying, and finding the exact bug.
Lioncache