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Improve x86 __fastcall wrapper (Closes #1331) (#1332)

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Alexandru Victor Macocian
2026-01-21 16:39:47 +01:00
parent 8306e10ffe
commit 1f8d4c126e
1 changed files with 89 additions and 17 deletions
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Daybreak.API/Interop/GWFastCall.cs
+89 -17
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@@ -11,37 +11,109 @@ public abstract class GWFastCall(GWAddressCache target)
public GWAddressCache Cache { get; } = target;
public abstract void Initialize();
protected unsafe static nint BuildFastCallThunk(nuint target)
/// <summary>
/// Builds a thunk for __fastcall with 1 parameter (ECX only).
/// </summary>
protected unsafe static nint BuildFastCallThunk1(nuint target)
{
if (target is 0)
{
return 0;
}
var code = stackalloc byte[13]
var code = stackalloc byte[10]
{
0x58, // pop eax (ret)
0x59, // pop ecx (ctx)
0x5A, // pop edx (edxVal)
0x5B, // pop ebx (wparam)
0x53, // push ebx (wparam)
0x59, // pop ecx (arg1)
0x50, // push eax (ret)
0xB8,0,0,0,0, // mov eax, TARGET
0xFF,0xE0 // jmp eax
}; // 13 bytes total
0xB8, 0, 0, 0, 0, // mov eax, TARGET
0xFF, 0xE0 // jmp eax
}; // 10 bytes total
const int TARGET_OFFSET = 7;
const int TARGET_OFFSET = 4;
Unsafe.WriteUnaligned(ref code[TARGET_OFFSET], (uint)target);
var mem = NativeMethods.VirtualAlloc(0, 13, NativeMethods.MEM_COMMIT | NativeMethods.MEM_RESERVE, NativeMethods.PAGE_EXECUTE_READWRITE);
var mem = NativeMethods.VirtualAlloc(0, 10, NativeMethods.MEM_COMMIT | NativeMethods.MEM_RESERVE, NativeMethods.PAGE_EXECUTE_READWRITE);
if (mem is 0)
{
throw new Win32Exception(Marshal.GetLastWin32Error(), "VirtualAlloc");
}
Buffer.MemoryCopy(code, (void*)mem, 13, 13);
Buffer.MemoryCopy(code, (void*)mem, 10, 10);
return mem;
}
/// <summary>
/// Builds a thunk for __fastcall with 2+ parameters (ECX and EDX).
/// </summary>
protected unsafe static nint BuildFastCallThunk2(nuint target)
{
if (target is 0)
{
return 0;
}
var code = stackalloc byte[11]
{
0x58, // pop eax (ret)
0x59, // pop ecx (ctx)
0x5A, // pop edx (edxVal)
0x50, // push eax (ret)
0xB8,0,0,0,0, // mov eax, TARGET
0xFF,0xE0 // jmp eax
}; // 11 bytes total
const int TARGET_OFFSET = 5;
Unsafe.WriteUnaligned(ref code[TARGET_OFFSET], (uint)target);
var mem = NativeMethods.VirtualAlloc(0, 11, NativeMethods.MEM_COMMIT | NativeMethods.MEM_RESERVE, NativeMethods.PAGE_EXECUTE_READWRITE);
if (mem is 0)
{
throw new Win32Exception(Marshal.GetLastWin32Error(), "VirtualAlloc");
}
Buffer.MemoryCopy(code, (void*)mem, 11, 11);
return mem;
}
}
public unsafe sealed class GWFastCall<T1, T2>(GWAddressCache target) : GWFastCall(target)
{
private delegate* unmanaged[Stdcall]<T1, T2> func = null;
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public unsafe T2? Invoke(T1 t1)
{
if (this.func is null)
{
this.Initialize();
}
if (this.func is not null)
{
if (typeof(T2) == typeof(Void))
{
((delegate* unmanaged[Stdcall]<T1, void>)this.func)(t1);
return default;
}
return this.func(t1);
}
return default;
}
public override void Initialize()
{
if (this.Cache.GetAddress() is not nuint addr ||
addr is 0)
{
return;
}
var call = BuildFastCallThunk1(addr);
this.func = (delegate* unmanaged[Stdcall]<T1, T2>)call;
}
}
public unsafe sealed class GWFastCall<T1, T2, T3>(GWAddressCache target) : GWFastCall(target)
@@ -78,7 +150,7 @@ public unsafe sealed class GWFastCall<T1, T2, T3>(GWAddressCache target) : GWFas
return;
}
var call = BuildFastCallThunk(addr);
var call = BuildFastCallThunk2(addr);
this.func = (delegate* unmanaged[Stdcall]<T1, T2, T3>)call;
}
}
@@ -117,7 +189,7 @@ public unsafe sealed class GWFastCall<T1, T2, T3, T4>(GWAddressCache target) : G
return;
}
var call = BuildFastCallThunk(addr);
var call = BuildFastCallThunk2(addr);
this.func = (delegate* unmanaged[Stdcall]<T1, T2, T3, T4>)call;
}
}
@@ -156,7 +228,7 @@ public unsafe sealed class GWFastCall<T1, T2, T3, T4, T5>(GWAddressCache target)
return;
}
var call = BuildFastCallThunk(addr);
var call = BuildFastCallThunk2(addr);
this.func = (delegate* unmanaged[Stdcall]<T1, T2, T3, T4, T5>)call;
}
}
@@ -195,7 +267,7 @@ public unsafe sealed class GWFastCall<T1, T2, T3, T4, T5, T6>(GWAddressCache tar
return;
}
var call = BuildFastCallThunk(addr);
var call = BuildFastCallThunk2(addr);
this.func = (delegate* unmanaged[Stdcall]<T1, T2, T3, T4, T5, T6>)call;
}
}
@@ -234,7 +306,7 @@ public unsafe sealed class GWFastCall<T1, T2, T3, T4, T5, T6, T7>(GWAddressCache
return;
}
var call = BuildFastCallThunk(addr);
var call = BuildFastCallThunk2(addr);
this.func = (delegate* unmanaged[Stdcall]<T1, T2, T3, T4, T5, T6, T7>)call;
}
}