- CommandProcessor: the FIFO registers shared by the CPU and GPU
threads are retro_atomic words, read and written through LoadReg and
StoreReg; MMIO's LowPart/HighPart take those words.
- Fifo: the video buffer write and seen pointers, the sync ticks and
the stop request.
- PerfQueryBase: the query count and results sit behind base-class
helpers that every backend (Metal too) uses instead of touching the
atomics.
- Custom assets: the loader's memory delta and an asset's last load
time are 64-bit words; Present's swap flag is an int.
- D3D's input layout, Vulkan's waiting_for_submit.
- InputCommon: a NumericSetting's value and the Wiimote and Android
rumble levels are kept as their bits in a 64-bit word; the
ControllerInterface flags, counter and aspect ratio are int words.
- CachedBlob's fill position and stop flag.
UICommon/GameFileCache is deleted: only the Android app's game list
used it, and that is not part of the core.
Every std::mutex, lock_guard, unique_lock, scoped_lock,
condition_variable, call_once and semaphore left in Source/Core is
replaced by a lock-free design:
- Input: the device list, control bindings, stick calibration and
default device are published snapshots read under a quiesce; a
rebind requested while another thread is rebinding is handed to
that thread instead of waited for.
- WiimoteReal: the pool thread owns the slots and runs commands from
an MPSC queue; the active Wiimotes are atomic slots.
- EXI/SI/IOS devices: socket and packet traffic goes through SPSC
rings or MPSC handoffs owned by one thread; USB scanning publishes
its device list, and libusb transfers drain through a CallGate.
- Memory cards: the flush thread applies change records queued by
the CPU thread.
- Custom assets: loads are scheduled as a published batch with an
atomic cursor, results come back over an MPSC stack, and busy
assets are skipped and retried.
- D3D state and GL program caches use insert-only atomic maps
(Common/AtomicHashMap.h).
- Logging appends with O_APPEND / FILE_APPEND_DATA; FatFs reports
busy instead of waiting; per-socket WSAStartup/WSACleanup.
Deleted as unused by the libretro core: the profiler, the FIFO
recorder, the volume verifier, the touch InputOverrider and the
GameCube adapter's libusb path.
Accomplished using `run-clang-tidy` with `performance-move-const-arg,performance-unnecessary-value-param,modernize-pass-by-value`.
Changed arguments to const references, removed them where inappropriate (e.g. sink parameters). Same with std::move.
Manually reviewed each change to make sure that it makes sense, and do something more appropriate if possible.