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using ARMeilleure.CodeGen.RegisterAllocators;
using ARMeilleure.IntermediateRepresentation;
using Ryujinx.Common.Memory;
using System.IO;
using System.Numerics;
namespace ARMeilleure.CodeGen.X86
{
class CodeGenContext
{
private readonly Stream _stream;
private readonly Operand[] _blockLabels;
public int StreamOffset => (int)_stream.Length;
public AllocationResult AllocResult { get; }
public Assembler Assembler { get; }
public BasicBlock CurrBlock { get; private set; }
public int CallArgsRegionSize { get; }
public int XmmSaveRegionSize { get; }
public CodeGenContext(AllocationResult allocResult, int maxCallArgs, int blocksCount, bool relocatable)
{
_stream = MemoryStreamManager.Shared.GetStream();
_blockLabels = new Operand[blocksCount];
AllocResult = allocResult;
Assembler = new Assembler(_stream, relocatable);
CallArgsRegionSize = GetCallArgsRegionSize(allocResult, maxCallArgs, out int xmmSaveRegionSize);
XmmSaveRegionSize = xmmSaveRegionSize;
}
private static int GetCallArgsRegionSize(AllocationResult allocResult, int maxCallArgs, out int xmmSaveRegionSize)
{
// We need to add 8 bytes to the total size, as the call to this function already pushed 8 bytes (the
// return address).
int intMask = CallingConvention.GetIntCalleeSavedRegisters() & allocResult.IntUsedRegisters;
int vecMask = CallingConvention.GetVecCalleeSavedRegisters() & allocResult.VecUsedRegisters;
xmmSaveRegionSize = BitOperations.PopCount((uint)vecMask) * 16;
int calleeSaveRegionSize = BitOperations.PopCount((uint)intMask) * 8 + xmmSaveRegionSize + 8;
int argsCount = maxCallArgs;
if (argsCount < 0)
{
// When the function has no calls, argsCount is -1. In this case, we don't need to allocate the shadow
// space.
argsCount = 0;
}
else if (argsCount < 4)
{
// The ABI mandates that the space for at least 4 arguments is reserved on the stack (this is called
// shadow space).
argsCount = 4;
}
// TODO: Align XMM save region to 16 bytes because unwinding on Windows requires it.
int frameSize = calleeSaveRegionSize + allocResult.SpillRegionSize;
// TODO: Instead of always multiplying by 16 (the largest possible size of a variable, since a V128 has 16
// bytes), we should calculate the exact size consumed by the arguments passed to the called functions on
// the stack.
int callArgsAndFrameSize = frameSize + argsCount * 16;
// Ensure that the Stack Pointer will be aligned to 16 bytes.
callArgsAndFrameSize = (callArgsAndFrameSize + 0xf) & ~0xf;
return callArgsAndFrameSize - frameSize;
}
public void EnterBlock(BasicBlock block)
{
Assembler.MarkLabel(GetLabel(block));
CurrBlock = block;
}
public void JumpTo(BasicBlock target)
{
Assembler.Jmp(GetLabel(target));
}
public void JumpTo(X86Condition condition, BasicBlock target)
{
Assembler.Jcc(condition, GetLabel(target));
}
private Operand GetLabel(BasicBlock block)
{
ref Operand label = ref _blockLabels[block.Index];
if (label == default)
{
label = Operand.Factory.Label();
}
return label;
}
}
}
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