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Optimize: Reduce and merge unnecessary move instructions #48

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Merged
merged 7 commits into from
Dec 29, 2024
Merged

Optimize: Reduce and merge unnecessary move instructions #48

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ddf6d44
Optimize: Reduce and merge unnecessary move instructions
Akeit0 Nov 4, 2024
e15f026
Optimize: MOVE MOVE SETTABLE Pattern
Akeit0 Nov 4, 2024
f9862f0
Optimize: MOVE Unm Pattern
Akeit0 Nov 4, 2024
b1fb869
Optimize: Merge more instructions
Akeit0 Nov 4, 2024
a3bf5df
Optimize: merge more patterns
Akeit0 Nov 4, 2024
466b2ac
Fix: fix SourcePositions on merge instructions
Akeit0 Nov 5, 2024
bd5ce70
Run formatter
nuskey8 Dec 29, 2024
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144 changes: 144 additions & 0 deletions src/Lua/CodeAnalysis/Compilation/FunctionCompilationContext.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -110,6 +110,150 @@ public void PushInstruction(in Instruction instruction, in SourcePosition positi
instructionPositions.Add(position);
}

/// <summary>
/// Push or merge the new instruction.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void PushOrMergeInstruction(int lastLocal, in Instruction instruction, in SourcePosition position, ref bool incrementStackPosition)
{
if (instructions.Length == 0)
{
instructions.Add(instruction);
instructionPositions.Add(position);
return;
}
ref var lastInstruction = ref instructions.AsSpan()[^1];
var opcode = instruction.OpCode;
switch (opcode)
{
case OpCode.Move:
// last A is not local variable
if (lastInstruction.A != lastLocal &&
// available to merge
lastInstruction.A == instruction.B &&
// not already merged
lastInstruction.A != lastInstruction.B)
{
switch (lastInstruction.OpCode)
{
case OpCode.GetTable:
case OpCode.Add:
case OpCode.Sub:
case OpCode.Mul:
case OpCode.Div:
case OpCode.Mod:
case OpCode.Pow:
case OpCode.Concat:
{
lastInstruction.A = instruction.A;
incrementStackPosition = false;
return;
}
}
}
break;
case OpCode.GetTable:
{
// Merge MOVE GetTable
if (lastInstruction.OpCode == OpCode.Move && lastLocal != lastInstruction.A)
{
if (lastInstruction.A == instruction.B)
{
lastInstruction = Instruction.GetTable(instruction.A, lastInstruction.B, instruction.C);
instructionPositions[^1] = position;
incrementStackPosition = false;
return;
}

}
break;
}
case OpCode.SetTable:
{
// Merge MOVE SETTABLE
if (lastInstruction.OpCode == OpCode.Move && lastLocal != lastInstruction.A)
{
var lastB = lastInstruction.B;
var lastA = lastInstruction.A;
if (lastB < 255 && lastA == instruction.A)
{
// Merge MOVE MOVE SETTABLE
if (instructions.Length > 2)
{
ref var last2Instruction = ref instructions.AsSpan()[^2];
var last2A = last2Instruction.A;
if (last2Instruction.OpCode == OpCode.Move && lastLocal != last2A && instruction.C == last2A)
{
last2Instruction = Instruction.SetTable((byte)(lastB), instruction.B, last2Instruction.B);
instructions.RemoveAtSwapback(instructions.Length - 1);
instructionPositions.RemoveAtSwapback(instructionPositions.Length - 1);
instructionPositions[^1] = position;
incrementStackPosition = false;
return;
}
}
lastInstruction = Instruction.SetTable((byte)(lastB), instruction.B, instruction.C);
instructionPositions[^1] = position;
incrementStackPosition = false;
return;
}

if (lastA == instruction.C)
{
lastInstruction = Instruction.SetTable(instruction.A, instruction.B, lastB);
instructionPositions[^1] = position;
incrementStackPosition = false;
return;
}
}
else if (lastInstruction.OpCode == OpCode.GetTabUp && instructions.Length >= 2)
{
ref var last2Instruction = ref instructions[^2];
var last2OpCode = last2Instruction.OpCode;
if (last2OpCode is OpCode.LoadK or OpCode.Move)
{

var last2A = last2Instruction.A;
if (last2A != lastLocal && instruction.C == last2A)
{
var c = last2OpCode == OpCode.LoadK ? last2Instruction.Bx + 256 : last2Instruction.B;
last2Instruction = lastInstruction;
lastInstruction = instruction with { C = (ushort)c };
instructionPositions[^2] = instructionPositions[^1];
instructionPositions[^1] = position;
incrementStackPosition = false;
return;
}
}
}
break;
}
case OpCode.Unm:
case OpCode.Not:
case OpCode.Len:
if (lastInstruction.OpCode == OpCode.Move && lastLocal != lastInstruction.A && lastInstruction.A == instruction.B)
{
lastInstruction = instruction with { B = lastInstruction.B }; ;
instructionPositions[^1] = position;
incrementStackPosition = false;
return;
}
break;
case OpCode.Return:
if (lastInstruction.OpCode == OpCode.Move && instruction.B == 2 && lastInstruction.B < 256)
{
lastInstruction = instruction with { A = (byte)lastInstruction.B };
instructionPositions[^1] = position;
incrementStackPosition = false;
return;
}
break;
}

instructions.Add(instruction);
instructionPositions.Add(position);
}

/// <summary>
/// Gets the index of the constant from the value, or if the constant is not registered it is added and its index is returned.
/// </summary>
Expand Down
14 changes: 11 additions & 3 deletions src/Lua/CodeAnalysis/Compilation/ScopeCompilationContext.cs
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Original file line number Diff line number Diff line change
Expand Up @@ -33,6 +33,8 @@ public static void Return(ScopeCompilationContext context)
readonly Dictionary<ReadOnlyMemory<char>, LocalVariableDescription> localVariables = new(256, Utf16StringMemoryComparer.Default);
readonly Dictionary<ReadOnlyMemory<char>, LabelDescription> labels = new(32, Utf16StringMemoryComparer.Default);

byte lastLocalVariableIndex;

public byte StackStartPosition { get; private set; }
public byte StackPosition { get; set; }

Expand Down Expand Up @@ -72,8 +74,11 @@ public FunctionCompilationContext CreateChildFunction()
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void PushInstruction(in Instruction instruction, SourcePosition position, bool incrementStackPosition = false)
{
Function.PushInstruction(instruction, position);
if (incrementStackPosition) StackPosition++;
Function.PushOrMergeInstruction(lastLocalVariableIndex, instruction, position, ref incrementStackPosition);
if (incrementStackPosition)
{
StackPosition++;
}
}

[MethodImpl(MethodImplOptions.AggressiveInlining)]
Expand All @@ -89,11 +94,13 @@ public void TryPushCloseUpValue(byte top, SourcePosition position)
/// Add new local variable.
/// </summary>
[MethodImpl(MethodImplOptions.AggressiveInlining)]
public void AddLocalVariable(ReadOnlyMemory<char> name, LocalVariableDescription description)
public void AddLocalVariable(ReadOnlyMemory<char> name, LocalVariableDescription description, bool markAsLastLocalVariable = true)
{
localVariables[name] = description;
lastLocalVariableIndex = description.RegisterIndex;
}


/// <summary>
/// Gets the local variable in scope.
/// </summary>
Expand Down Expand Up @@ -157,6 +164,7 @@ public void Reset()
HasCapturedLocalVariables = false;
localVariables.Clear();
labels.Clear();
lastLocalVariableIndex = 0;
}

/// <summary>
Expand Down