Whenever JitBaseBlockCache::Clear() got called, it threw away the memory mapping for the fast block map and created a new one. This new mapping typically got mapped at the same address at the old one, but this is not guaranteed. The pointer to the mapping gets embedded in the generated dispatcher code in Jit64AsmRoutineManager::Generate(), which is only called once on game boot, so if the new mapping ended up at a different address than the old one, the pointer in the ASM pointed at garbage, leading to a crash.
This fixes the issue by guaranteeing that the new mapping is mapped at the same address.
This fixes a problem where changing the JIT debug settings on
Android while a game was running wouldn't cause the changed settings
to apply to code blocks that already had been compiled.
In theory, our config system supports calling Set from any thread. But
because we have config callbacks that call RunAsCPUThread, it's a lot
more restricted in practice. Calling Set from any thread other than the
host thread or the CPU thread is formally thread unsafe, and calling Set
on the host thread while the CPU thread is showing a panic alert causes
a deadlock. This is especially a problem because 04072f0 made the
"Ignore for this session" button in panic alerts call Set.
Because so many of our config callbacks want their code to run on the
CPU thread, I thought it would make sense to have a centralized way to
move execution to the CPU thread for config callbacks. To solve the
deadlock problem, this new way is non-blocking. This means that threads
other than the CPU thread might continue executing before the CPU thread
is informed of the new config, but I don't think there's any problem
with that.
Intends to fix https://bugs.dolphin-emu.org/issues/13108.
Now block link nearcode is back to a length of three instructions.
Unfortunately, the code I'm adding to Jit.cpp ends up being a bit messy
because we need to handle the case of already being in farcode...
By using a shm memory segment for the fast_block_map that is sparsely
allocated (i.e. on write by the OS) instead of a statically allocated
array we can make the block lookup faster by:
* Having a bigger space available for lookup that doesn't take up
too much memory, because the OS will only allocate the needed
pages when written to.
* Decrease the time spent to lookup a block in the assembly dispatcher
due to less comparisions and shorter code (for example the pc check
has been entirely dropped since only the msrBits need to be validated).
When the JIT block cache is full the shm segment will also be released
and reallocated to avoid allocating too much memory. It will also be
reset when the instruction cache is flushed by the PPC code to avoid
having stale entries.
Also fallback to the original method in case the memory segment couldn't
be allocated.
Small optimization. By not calling WriteExit, the block linking system
never finds out about the exit we're doing, saving us from having to
disable block linking.
The new `dispatcher_no_timing_check` is the same as `dispatcher_no_check`
except it includes the "stepping check" in debug mode. This lets us avoid
the `m_enable_debugging ? dispatcher : dispatcher_no_check` dance.
It became irrelevant in 952dfcd610, when the define was removed; now, the code the comment is referring to is in JitRegister.cpp, and oprofile is controlled by cmake.
This is done entirely through interpreter fallbacks. It would
probably be possible to implement this using host exception
handlers instead, but I think it would be a lot of complexity
for a rarely used feature, so let's not do it for now.
For performance reasons, there are two settings for this feature:
One setting which does enables just what True Crime: New York City
needs and one setting which enables it all. The latter makes
almost all float instructions fall back to the interpreter.
This reverts commit 66b992cfe4.
A new (additional) correctness issue was revealed in the old
AArch64 code when applying it on top of modern JitArm64:
LSR was being used when LSRV was intended. This commit uses LSRV.
SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
