All buffers should be disowned leaving their respective compilation
sites, and reowning a buffer should never have the flag already be
owned.
Throw an assert in both cases because that would be a programming error
and result in some squirrely buffer handling
UpdateTopForPop_Slow() now invalidates ST(0)'s tag by default,
so every slow-path StackPop() does this consistently instead of
the previous special case only in OP_POPSTACKDESTROY.
FINCSTP is an exception as it only moves the stack pointer without
invalidating the tag.
Decode a few bytes in advance to get a hashable prefix to use as key.
Generate touched pages dynamically since they can be misaligned now, as the
cached-hit guest code isn't necessarily in the same spot as the store was.
PR #5902 technically introduced a bug where we would read past the end
of bounds for thunk instructions when full smc was enabled. Luckily this
never occurs in practice as the Mono hacks never are on VDSO boundaries,
and no one is expected to enable full smc detection really.
Switch this path over to using crc32 unconditionally. This raises our
minspec technically to armv8-a+crc, but nothing that matters shipped
without crc so it's fine.
This also is a minor speed and JIT size reduction due less branches
polluting the BTB. But really only for mono/unity games.
Requires revving the DiskCache version again.
Does less hashing, improves hit rate when there's data adjacent to code,
and/or when the SMC check makes us rebuild code that hasn't actually been
changed.
The JIT was doing a bunch of additional work where it was saving and
restoring registers and then juggling the arguments back in to a stack
frame. All of this is nonsensical without the optimization where we
could call syscalls inline without a stack frame.
Instead remove this optimization entirely and behave like a "generic"
syscall path always. The Linux syscall handler now pulls the arguments
out of the CPU context directly and stores the result back in to RAX
directly as well.
This has knock-on effects where technically syscalls are
going to be slightly faster because no stack frame setup for the
arguments, but additionally we are going to be able to have syscalls be
proper serialization points where we can interrupt the syscall and
long-jump out without problems.
Bumps the DiskCache version again because it causes codegen to change.
This is unfiltered data that ends up in HostFeatures. If it was
serialized when set then it would effectively never allow the code
serialization to be used.
If we're shrinking the L1 cache then we just deleted the entry that we
just looked up. Add it back to ensure we don't get yet another lookup
for this entry.
Growing widens L1PointerMask without touching the table, so an entry whose
address has the new mask bit set sits where InvalidateCache no longer looks,
and a later shrink hands it back to the JIT. Wipe [0, old) on grow, the way
the shrink wipes [new, MAX); the still-valid entries go with it.
Compute a bucket hash and use it in the cache path to avoid grouping entries
that will never make sense together. Don't trust the path, though, and also
lace it into the keys themselves, so that eg. a RO cache miss can never turn
into corruption.
Keep a readable metadata entry at the beginning of the cache, with readable
version, bitness and serialized config.
Use printable characters in FOZ key names as intended.
We were assuming that SHLD undefined behaviour matches SHL, but the
specification actually changes a `ge` comparison to `gt`, which means a
shift of 16 isn't UB!
Thanks to the impeccable @OFFTKP in #5842 for bringing this up as it took a bit
for me to figure out what was actually wrong here. I modified their
unittest to cover more just to ensure we don't break it.
As long as the hash is smaller than 64-bits we can just return the bits
encoded directly. Codegen slightly changes with this packed
representation, but doesn't really matter.
Also removes ICacheLineSize as that doesn't actually affect codegen for
us. Once we add 27 more HostFeatures we can switch the hash over to
XXH3.
We actually never use this anymore, we instead always pass zero for
both, and then rely on the thread inheritance model or setting the
values manually. Now that we expose visibility of the
InternalThreadState to the frontend they just access it directly.
Just a smidge of cleanup, NFC.
Serializes every option, even ones that are set to default to ensure
validation that if any config option value is added or changed that they
are captured.
Skips a handful of options that are either meta options, environment
options that don't matter, or HostFeatures which is handled elsewhere.
(HostFeatures will be controlling bucketing rather than the remaining
options).
This serialization is currently 1413 bytes and generates in 17580ns on
my A1A. So it's not the fastest, definitely don't want to be generating
it constantly per process.
FEX Relocations now live at an offset from the `CodeData.BlockBegin` of the
code. Regardless of where the relocation moves to, it should always be
relative to that address. This is what makes it PIC compatible.
We were preemptively offsetting the relocation location to be relative
to the memory base in the buffer, which is unnecessary and causes code
caching to basically relocate twice to get the real location.
So in JIT.cpp, stop relocating the offsets, they're already relative to
`BlockBegin`, which is offset 0.
Then when storing the relocation, stop relocating offsets AGAIN because it's
already relative to the code being serialized.
Then when loading the relocations in `CodeCache::ApplyCodeRelocations`
stop relocating offsets YET ANOTHER TIME.
All this is to say that relocation offsets are already PIC and relative
to offset 0, so we don't need to do it three times.
I accidentally replaced a couple usages of `AllocatedSize` with
`GetAllocatedSize()`. This resulted in a JIT buffer that ran out of
space would actually allocate a slightly smaller buffer each time, and
then it cascades downwards resulting in catastrophic performance.
Fix the use in `SharedCodeBufferManager.cpp` and `Core.cpp` which were
incorrect and renames the function to be more explicit.
Noticed while taking a look at the relocations that we were technically
not doing alignment before writing down code size.
- Make sure Align16B isn't used with unaligned code with assert
- Switch an `Align` over to `Align(16)` to force 16-byte alignment
- Without NOP insertion, as this is data at this point, so just zeros.
- Record data size after that alignment
- Remove the `Align16B` that occurred afterwards
- Previous query between alignments would leave us with up to 12 bytes
unaccounted for.
- Ensure everything is using the correct sizes by not querying again
- Ensure that emission buffer abuse can't happen by zeroing the buffer.
The various places that were using the CodeBuffer object were using
internal implementation details that are changing as we move over to a
bitmap allocator.
Preempt this by hiding some of the implementation details early without
changing behaviour. `GetBufferBase` is still technically leaking some of
the internal details, but it needs changes around how relocations are
being handled and how the disk cache validation works in order to handle
that right now.
Should be no functional change.
Ryan Houdek