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using ARMeilleure.IntermediateRepresentation;
using ARMeilleure.Translation;
using Ryujinx.Common.Memory.PartialUnmaps;
using System;
using System.Runtime.InteropServices;
using static ARMeilleure.IntermediateRepresentation.Operand.Factory;
namespace ARMeilleure.Signal
{
/// <summary>
/// Methods to handle signals caused by partial unmaps. See the structs for C# implementations of the methods.
/// </summary>
internal static partial class WindowsPartialUnmapHandler
{
[LibraryImport("kernel32.dll", SetLastError = true, EntryPoint = "LoadLibraryA")]
private static partial IntPtr LoadLibrary([MarshalAs(UnmanagedType.LPStr)] string lpFileName);
[LibraryImport("kernel32.dll", SetLastError = true)]
private static partial IntPtr GetProcAddress(IntPtr hModule, [MarshalAs(UnmanagedType.LPStr)] string procName);
private static IntPtr _getCurrentThreadIdPtr;
public static IntPtr GetCurrentThreadIdFunc()
{
if (_getCurrentThreadIdPtr == IntPtr.Zero)
{
IntPtr handle = LoadLibrary("kernel32.dll");
_getCurrentThreadIdPtr = GetProcAddress(handle, "GetCurrentThreadId");
}
return _getCurrentThreadIdPtr;
}
public static Operand EmitRetryFromAccessViolation(EmitterContext context)
{
IntPtr partialRemapStatePtr = PartialUnmapState.GlobalState;
IntPtr localCountsPtr = IntPtr.Add(partialRemapStatePtr, PartialUnmapState.LocalCountsOffset);
// Get the lock first.
EmitNativeReaderLockAcquire(context, IntPtr.Add(partialRemapStatePtr, PartialUnmapState.PartialUnmapLockOffset));
IntPtr getCurrentThreadId = GetCurrentThreadIdFunc();
Operand threadId = context.Call(Const((ulong)getCurrentThreadId), OperandType.I32);
Operand threadIndex = EmitThreadLocalMapIntGetOrReserve(context, localCountsPtr, threadId, Const(0));
Operand endLabel = Label();
Operand retry = context.AllocateLocal(OperandType.I32);
Operand threadIndexValidLabel = Label();
context.BranchIfFalse(threadIndexValidLabel, context.ICompareEqual(threadIndex, Const(-1)));
context.Copy(retry, Const(1)); // Always retry when thread local cannot be allocated.
context.Branch(endLabel);
context.MarkLabel(threadIndexValidLabel);
Operand threadLocalPartialUnmapsPtr = EmitThreadLocalMapIntGetValuePtr(context, localCountsPtr, threadIndex);
Operand threadLocalPartialUnmaps = context.Load(OperandType.I32, threadLocalPartialUnmapsPtr);
Operand partialUnmapsCount = context.Load(OperandType.I32, Const((ulong)IntPtr.Add(partialRemapStatePtr, PartialUnmapState.PartialUnmapsCountOffset)));
context.Copy(retry, context.ICompareNotEqual(threadLocalPartialUnmaps, partialUnmapsCount));
Operand noRetryLabel = Label();
context.BranchIfFalse(noRetryLabel, retry);
// if (retry) {
context.Store(threadLocalPartialUnmapsPtr, partialUnmapsCount);
context.Branch(endLabel);
context.MarkLabel(noRetryLabel);
// }
context.MarkLabel(endLabel);
// Finally, release the lock and return the retry value.
EmitNativeReaderLockRelease(context, IntPtr.Add(partialRemapStatePtr, PartialUnmapState.PartialUnmapLockOffset));
return retry;
}
public static Operand EmitThreadLocalMapIntGetOrReserve(EmitterContext context, IntPtr threadLocalMapPtr, Operand threadId, Operand initialState)
{
Operand idsPtr = Const((ulong)IntPtr.Add(threadLocalMapPtr, ThreadLocalMap<int>.ThreadIdsOffset));
Operand i = context.AllocateLocal(OperandType.I32);
context.Copy(i, Const(0));
// (Loop 1) Check all slots for a matching Thread ID (while also trying to allocate)
Operand endLabel = Label();
Operand loopLabel = Label();
context.MarkLabel(loopLabel);
Operand offset = context.Multiply(i, Const(sizeof(int)));
Operand idPtr = context.Add(idsPtr, context.SignExtend32(OperandType.I64, offset));
// Check that this slot has the thread ID.
Operand existingId = context.CompareAndSwap(idPtr, threadId, threadId);
// If it was already the thread ID, then we just need to return i.
context.BranchIfTrue(endLabel, context.ICompareEqual(existingId, threadId));
context.Copy(i, context.Add(i, Const(1)));
context.BranchIfTrue(loopLabel, context.ICompareLess(i, Const(ThreadLocalMap<int>.MapSize)));
// (Loop 2) Try take a slot that is 0 with our Thread ID.
context.Copy(i, Const(0)); // Reset i.
Operand loop2Label = Label();
context.MarkLabel(loop2Label);
Operand offset2 = context.Multiply(i, Const(sizeof(int)));
Operand idPtr2 = context.Add(idsPtr, context.SignExtend32(OperandType.I64, offset2));
// Try and swap in the thread id on top of 0.
Operand existingId2 = context.CompareAndSwap(idPtr2, Const(0), threadId);
Operand idNot0Label = Label();
// If it was 0, then we need to initialize the struct entry and return i.
context.BranchIfFalse(idNot0Label, context.ICompareEqual(existingId2, Const(0)));
Operand structsPtr = Const((ulong)IntPtr.Add(threadLocalMapPtr, ThreadLocalMap<int>.StructsOffset));
Operand structPtr = context.Add(structsPtr, context.SignExtend32(OperandType.I64, offset2));
context.Store(structPtr, initialState);
context.Branch(endLabel);
context.MarkLabel(idNot0Label);
context.Copy(i, context.Add(i, Const(1)));
context.BranchIfTrue(loop2Label, context.ICompareLess(i, Const(ThreadLocalMap<int>.MapSize)));
context.Copy(i, Const(-1)); // Could not place the thread in the list.
context.MarkLabel(endLabel);
return context.Copy(i);
}
private static Operand EmitThreadLocalMapIntGetValuePtr(EmitterContext context, IntPtr threadLocalMapPtr, Operand index)
{
Operand offset = context.Multiply(index, Const(sizeof(int)));
Operand structsPtr = Const((ulong)IntPtr.Add(threadLocalMapPtr, ThreadLocalMap<int>.StructsOffset));
return context.Add(structsPtr, context.SignExtend32(OperandType.I64, offset));
}
private static void EmitAtomicAddI32(EmitterContext context, Operand ptr, Operand additive)
{
Operand loop = Label();
context.MarkLabel(loop);
Operand initial = context.Load(OperandType.I32, ptr);
Operand newValue = context.Add(initial, additive);
Operand replaced = context.CompareAndSwap(ptr, initial, newValue);
context.BranchIfFalse(loop, context.ICompareEqual(initial, replaced));
}
private static void EmitNativeReaderLockAcquire(EmitterContext context, IntPtr nativeReaderLockPtr)
{
Operand writeLockPtr = Const((ulong)IntPtr.Add(nativeReaderLockPtr, NativeReaderWriterLock.WriteLockOffset));
// Spin until we can acquire the write lock.
Operand spinLabel = Label();
context.MarkLabel(spinLabel);
// Old value must be 0 to continue (we gained the write lock)
context.BranchIfTrue(spinLabel, context.CompareAndSwap(writeLockPtr, Const(0), Const(1)));
// Increment reader count.
EmitAtomicAddI32(context, Const((ulong)IntPtr.Add(nativeReaderLockPtr, NativeReaderWriterLock.ReaderCountOffset)), Const(1));
// Release write lock.
context.CompareAndSwap(writeLockPtr, Const(1), Const(0));
}
private static void EmitNativeReaderLockRelease(EmitterContext context, IntPtr nativeReaderLockPtr)
{
// Decrement reader count.
EmitAtomicAddI32(context, Const((ulong)IntPtr.Add(nativeReaderLockPtr, NativeReaderWriterLock.ReaderCountOffset)), Const(-1));
}
}
}
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