CMake has had the `MINGW` builtin to describe MinGW targets since at
least version 3.2, so it can safely be used. This variable is also set
for the MSYS2 environments, so CLANGARM64 also correctly sets `MINGW`.
Note that this depends on https://github.com/FEX-Emu/jemalloc/pull/11.
Signed-off-by: crueter <crueter@eden-emu.dev>
Windows caches can only really work safely if they are exclusive to a
prefix due to the state for things like sharing modes that is tied to
the per-prefix wineserver and codemaps encoding prefix-local paths for
system DLLs.
Recent CPUs do nop fusion with the following instruction, this gives the
CPU the best chance to do fusion with something that actually does work.
Very trivial, doesn't do this for the more complex handling below these
as counting the number of moves before nop emitting is messy.
Instead of just a trivial pad being on or off, support a tri-state
on/off/auto where on will always pad, off will never pad, and auto will
pad only if code caching is enabled.
Further augment this by allowing a byte-width to be passed in, which can
be used with pointers to force a 48-bit VA width to only ever pad to
three instructions, reducing the common worst-case situation from 4
instructions to 3. This works because we're not going to expose a VA
width larger than 47-bit to the guest.
Fixes the handful of use-cases that explicitly chose their NOP padding,
and a bug in Arm64Relocations.cpp where it was incorrectly asking to not
receive padding even though it requires it.
and use it to commonise volatile metadata code (adding WOW64 image
voltmd support in the process). This will be extended to track mapped
images for code caching.
When relocations are loaded, all immediates read from memory are checked
against the relocation map and transformed into an appropriately
sign-extended entrypoint-relative variant of the specific operands
addressing mode. As almost every case of an unhandled relocation will
lead to a later, likely harder to debug, crash at runtime just bail out
early if any such cases are encountered. Note that while this
handles/detects all cases of relocated immediates, if relocations were
applied to instructions themselves (occurs in some malware variants)
these would be missed without any errors reported.
When compiling code at runtime there is no harm to including jumps to
different sections within a multiblock, when enforcing as such would
introduce a lookup cost for every decode invocation (or some caching).
However when compiling offline as each cache blob is tied to a specific
library these boundaries should be enforced.
In order to support code caching of 32-bit libraries, any library-base
relative relocations on the guest must be transformed into FEX
relocations so e.g. absolute jumps or loads refer to the correct
location when the library is loaded at a different base address.
I noticed that we weren't actually testing 32-bit displacement on
64-bit. This is an edge case on 64-bit where you can have 32-bit
displacement WITHOUT it being RIP relative. This is very uncommonly used
but is technically a possibility where 64-bit code can access an
absolute address in the lower 2GB.
With negative addresses you could technically access canonical kernel
addresses in the lower 2GB if they were mapped in userspace, but since
they aren't this is untestable (FEX also doesn't handle canonical kernel
addresses correctly anyway).
`MemoryData.asm` accidentally tested this but it didn't test both load
and store sides. So let's be a bit more stringent on this.
crueter