Ryujinx-git/ARMeilleure/CodeGen/X86/PreAllocator.cs
gdkchan f0562b9c75
CPU: Avoid argument value copies on the JIT (#4484)
* Minor refactoring of the pre-allocator

* Avoid LoadArgument copies

* PPTC version bump
2023-03-08 23:25:35 +01:00

790 lines
No EOL
31 KiB
C#

using ARMeilleure.CodeGen.RegisterAllocators;
using ARMeilleure.IntermediateRepresentation;
using ARMeilleure.Translation;
using System;
using System.Diagnostics;
using static ARMeilleure.IntermediateRepresentation.Operand.Factory;
using static ARMeilleure.IntermediateRepresentation.Operation.Factory;
namespace ARMeilleure.CodeGen.X86
{
class PreAllocator
{
public static void RunPass(CompilerContext cctx, StackAllocator stackAlloc, out int maxCallArgs)
{
maxCallArgs = -1;
Span<Operation> buffer = default;
CallConvName callConv = CallingConvention.GetCurrentCallConv();
Operand[] preservedArgs = new Operand[CallingConvention.GetArgumentsOnRegsCount()];
for (BasicBlock block = cctx.Cfg.Blocks.First; block != null; block = block.ListNext)
{
Operation nextNode;
for (Operation node = block.Operations.First; node != default; node = nextNode)
{
nextNode = node.ListNext;
if (node.Instruction == Instruction.Phi)
{
continue;
}
InsertConstantRegCopies(block.Operations, node);
InsertDestructiveRegCopies(block.Operations, node);
InsertConstrainedRegCopies(block.Operations, node);
switch (node.Instruction)
{
case Instruction.Call:
// Get the maximum number of arguments used on a call.
// On windows, when a struct is returned from the call,
// we also need to pass the pointer where the struct
// should be written on the first argument.
int argsCount = node.SourcesCount - 1;
if (node.Destination != default && node.Destination.Type == OperandType.V128)
{
argsCount++;
}
if (maxCallArgs < argsCount)
{
maxCallArgs = argsCount;
}
// Copy values to registers expected by the function
// being called, as mandated by the ABI.
if (callConv == CallConvName.Windows)
{
PreAllocatorWindows.InsertCallCopies(block.Operations, stackAlloc, node);
}
else /* if (callConv == CallConvName.SystemV) */
{
PreAllocatorSystemV.InsertCallCopies(block.Operations, node);
}
break;
case Instruction.ConvertToFPUI:
GenerateConvertToFPUI(block.Operations, node);
break;
case Instruction.LoadArgument:
if (callConv == CallConvName.Windows)
{
nextNode = PreAllocatorWindows.InsertLoadArgumentCopy(cctx, ref buffer, block.Operations, preservedArgs, node);
}
else /* if (callConv == CallConvName.SystemV) */
{
nextNode = PreAllocatorSystemV.InsertLoadArgumentCopy(cctx, ref buffer, block.Operations, preservedArgs, node);
}
break;
case Instruction.Negate:
if (!node.GetSource(0).Type.IsInteger())
{
GenerateNegate(block.Operations, node);
}
break;
case Instruction.Return:
if (callConv == CallConvName.Windows)
{
PreAllocatorWindows.InsertReturnCopy(cctx, block.Operations, preservedArgs, node);
}
else /* if (callConv == CallConvName.SystemV) */
{
PreAllocatorSystemV.InsertReturnCopy(block.Operations, node);
}
break;
case Instruction.Tailcall:
if (callConv == CallConvName.Windows)
{
PreAllocatorWindows.InsertTailcallCopies(block.Operations, stackAlloc, node);
}
else
{
PreAllocatorSystemV.InsertTailcallCopies(block.Operations, stackAlloc, node);
}
break;
case Instruction.VectorInsert8:
if (!HardwareCapabilities.SupportsSse41)
{
GenerateVectorInsert8(block.Operations, node);
}
break;
case Instruction.Extended:
if (node.Intrinsic == Intrinsic.X86Mxcsrmb || node.Intrinsic == Intrinsic.X86Mxcsrub)
{
int stackOffset = stackAlloc.Allocate(OperandType.I32);
node.SetSources(new Operand[] { Const(stackOffset), node.GetSource(0) });
}
break;
}
}
}
}
protected static void InsertConstantRegCopies(IntrusiveList<Operation> nodes, Operation node)
{
if (node.SourcesCount == 0 || IsXmmIntrinsic(node))
{
return;
}
Instruction inst = node.Instruction;
Operand src1 = node.GetSource(0);
Operand src2;
if (src1.Kind == OperandKind.Constant)
{
if (!src1.Type.IsInteger())
{
// Handle non-integer types (FP32, FP64 and V128).
// For instructions without an immediate operand, we do the following:
// - Insert a copy with the constant value (as integer) to a GPR.
// - Insert a copy from the GPR to a XMM register.
// - Replace the constant use with the XMM register.
src1 = AddXmmCopy(nodes, node, src1);
node.SetSource(0, src1);
}
else if (!HasConstSrc1(inst))
{
// Handle integer types.
// Most ALU instructions accepts a 32-bits immediate on the second operand.
// We need to ensure the following:
// - If the constant is on operand 1, we need to move it.
// -- But first, we try to swap operand 1 and 2 if the instruction is commutative.
// -- Doing so may allow us to encode the constant as operand 2 and avoid a copy.
// - If the constant is on operand 2, we check if the instruction supports it,
// if not, we also add a copy. 64-bits constants are usually not supported.
if (IsCommutative(node))
{
src2 = node.GetSource(1);
Operand temp = src1;
src1 = src2;
src2 = temp;
node.SetSource(0, src1);
node.SetSource(1, src2);
}
if (src1.Kind == OperandKind.Constant)
{
src1 = AddCopy(nodes, node, src1);
node.SetSource(0, src1);
}
}
}
if (node.SourcesCount < 2)
{
return;
}
src2 = node.GetSource(1);
if (src2.Kind == OperandKind.Constant)
{
if (!src2.Type.IsInteger())
{
src2 = AddXmmCopy(nodes, node, src2);
node.SetSource(1, src2);
}
else if (!HasConstSrc2(inst) || CodeGenCommon.IsLongConst(src2))
{
src2 = AddCopy(nodes, node, src2);
node.SetSource(1, src2);
}
}
}
protected static void InsertConstrainedRegCopies(IntrusiveList<Operation> nodes, Operation node)
{
Operand dest = node.Destination;
switch (node.Instruction)
{
case Instruction.CompareAndSwap:
case Instruction.CompareAndSwap16:
case Instruction.CompareAndSwap8:
{
OperandType type = node.GetSource(1).Type;
if (type == OperandType.V128)
{
// Handle the many restrictions of the compare and exchange (16 bytes) instruction:
// - The expected value should be in RDX:RAX.
// - The new value to be written should be in RCX:RBX.
// - The value at the memory location is loaded to RDX:RAX.
void SplitOperand(Operand source, Operand lr, Operand hr)
{
nodes.AddBefore(node, Operation(Instruction.VectorExtract, lr, source, Const(0)));
nodes.AddBefore(node, Operation(Instruction.VectorExtract, hr, source, Const(1)));
}
Operand rax = Gpr(X86Register.Rax, OperandType.I64);
Operand rbx = Gpr(X86Register.Rbx, OperandType.I64);
Operand rcx = Gpr(X86Register.Rcx, OperandType.I64);
Operand rdx = Gpr(X86Register.Rdx, OperandType.I64);
SplitOperand(node.GetSource(1), rax, rdx);
SplitOperand(node.GetSource(2), rbx, rcx);
Operation operation = node;
node = nodes.AddAfter(node, Operation(Instruction.VectorCreateScalar, dest, rax));
nodes.AddAfter(node, Operation(Instruction.VectorInsert, dest, dest, rdx, Const(1)));
operation.SetDestinations(new Operand[] { rdx, rax });
operation.SetSources(new Operand[] { operation.GetSource(0), rdx, rax, rcx, rbx });
}
else
{
// Handle the many restrictions of the compare and exchange (32/64) instruction:
// - The expected value should be in (E/R)AX.
// - The value at the memory location is loaded to (E/R)AX.
Operand expected = node.GetSource(1);
Operand newValue = node.GetSource(2);
Operand rax = Gpr(X86Register.Rax, expected.Type);
nodes.AddBefore(node, Operation(Instruction.Copy, rax, expected));
// We need to store the new value into a temp, since it may
// be a constant, and this instruction does not support immediate operands.
Operand temp = Local(newValue.Type);
nodes.AddBefore(node, Operation(Instruction.Copy, temp, newValue));
node.SetSources(new Operand[] { node.GetSource(0), rax, temp });
nodes.AddAfter(node, Operation(Instruction.Copy, dest, rax));
node.Destination = rax;
}
break;
}
case Instruction.Divide:
case Instruction.DivideUI:
{
// Handle the many restrictions of the division instructions:
// - The dividend is always in RDX:RAX.
// - The result is always in RAX.
// - Additionally it also writes the remainder in RDX.
if (dest.Type.IsInteger())
{
Operand src1 = node.GetSource(0);
Operand rax = Gpr(X86Register.Rax, src1.Type);
Operand rdx = Gpr(X86Register.Rdx, src1.Type);
nodes.AddBefore(node, Operation(Instruction.Copy, rax, src1));
nodes.AddBefore(node, Operation(Instruction.Clobber, rdx));
nodes.AddAfter(node, Operation(Instruction.Copy, dest, rax));
node.SetSources(new Operand[] { rdx, rax, node.GetSource(1) });
node.Destination = rax;
}
break;
}
case Instruction.Extended:
{
bool isBlend = node.Intrinsic == Intrinsic.X86Blendvpd ||
node.Intrinsic == Intrinsic.X86Blendvps ||
node.Intrinsic == Intrinsic.X86Pblendvb;
// BLENDVPD, BLENDVPS, PBLENDVB last operand is always implied to be XMM0 when VEX is not supported.
// SHA256RNDS2 always has an implied XMM0 as a last operand.
if ((isBlend && !HardwareCapabilities.SupportsVexEncoding) || node.Intrinsic == Intrinsic.X86Sha256Rnds2)
{
Operand xmm0 = Xmm(X86Register.Xmm0, OperandType.V128);
nodes.AddBefore(node, Operation(Instruction.Copy, xmm0, node.GetSource(2)));
node.SetSource(2, xmm0);
}
break;
}
case Instruction.Multiply64HighSI:
case Instruction.Multiply64HighUI:
{
// Handle the many restrictions of the i64 * i64 = i128 multiply instructions:
// - The multiplicand is always in RAX.
// - The lower 64-bits of the result is always in RAX.
// - The higher 64-bits of the result is always in RDX.
Operand src1 = node.GetSource(0);
Operand rax = Gpr(X86Register.Rax, src1.Type);
Operand rdx = Gpr(X86Register.Rdx, src1.Type);
nodes.AddBefore(node, Operation(Instruction.Copy, rax, src1));
node.SetSource(0, rax);
nodes.AddAfter(node, Operation(Instruction.Copy, dest, rdx));
node.SetDestinations(new Operand[] { rdx, rax });
break;
}
case Instruction.RotateRight:
case Instruction.ShiftLeft:
case Instruction.ShiftRightSI:
case Instruction.ShiftRightUI:
{
// The shift register is always implied to be CL (low 8-bits of RCX or ECX).
if (node.GetSource(1).Kind == OperandKind.LocalVariable)
{
Operand rcx = Gpr(X86Register.Rcx, OperandType.I32);
nodes.AddBefore(node, Operation(Instruction.Copy, rcx, node.GetSource(1)));
node.SetSource(1, rcx);
}
break;
}
}
}
protected static void InsertDestructiveRegCopies(IntrusiveList<Operation> nodes, Operation node)
{
if (node.Destination == default || node.SourcesCount == 0)
{
return;
}
Instruction inst = node.Instruction;
Operand dest = node.Destination;
Operand src1 = node.GetSource(0);
// The multiply instruction (that maps to IMUL) is somewhat special, it has
// a three operand form where the second source is a immediate value.
bool threeOperandForm = inst == Instruction.Multiply && node.GetSource(1).Kind == OperandKind.Constant;
if (IsSameOperandDestSrc1(node) && src1.Kind == OperandKind.LocalVariable && !threeOperandForm)
{
bool useNewLocal = false;
for (int srcIndex = 1; srcIndex < node.SourcesCount; srcIndex++)
{
if (node.GetSource(srcIndex) == dest)
{
useNewLocal = true;
break;
}
}
if (useNewLocal)
{
// Dest is being used as some source already, we need to use a new
// local to store the temporary value, otherwise the value on dest
// local would be overwritten.
Operand temp = Local(dest.Type);
nodes.AddBefore(node, Operation(Instruction.Copy, temp, src1));
node.SetSource(0, temp);
nodes.AddAfter(node, Operation(Instruction.Copy, dest, temp));
node.Destination = temp;
}
else
{
nodes.AddBefore(node, Operation(Instruction.Copy, dest, src1));
node.SetSource(0, dest);
}
}
else if (inst == Instruction.ConditionalSelect)
{
Operand src2 = node.GetSource(1);
Operand src3 = node.GetSource(2);
if (src1 == dest || src2 == dest)
{
Operand temp = Local(dest.Type);
nodes.AddBefore(node, Operation(Instruction.Copy, temp, src3));
node.SetSource(2, temp);
nodes.AddAfter(node, Operation(Instruction.Copy, dest, temp));
node.Destination = temp;
}
else
{
nodes.AddBefore(node, Operation(Instruction.Copy, dest, src3));
node.SetSource(2, dest);
}
}
}
private static void GenerateConvertToFPUI(IntrusiveList<Operation> nodes, Operation node)
{
// Unsigned integer to FP conversions are not supported on X86.
// We need to turn them into signed integer to FP conversions, and
// adjust the final result.
Operand dest = node.Destination;
Operand source = node.GetSource(0);
Debug.Assert(source.Type.IsInteger(), $"Invalid source type \"{source.Type}\".");
Operation currentNode = node;
if (source.Type == OperandType.I32)
{
// For 32-bits integers, we can just zero-extend to 64-bits,
// and then use the 64-bits signed conversion instructions.
Operand zex = Local(OperandType.I64);
node = nodes.AddAfter(node, Operation(Instruction.ZeroExtend32, zex, source));
node = nodes.AddAfter(node, Operation(Instruction.ConvertToFP, dest, zex));
}
else /* if (source.Type == OperandType.I64) */
{
// For 64-bits integers, we need to do the following:
// - Ensure that the integer has the most significant bit clear.
// -- This can be done by shifting the value right by 1, that is, dividing by 2.
// -- The least significant bit is lost in this case though.
// - We can then convert the shifted value with a signed integer instruction.
// - The result still needs to be corrected after that.
// -- First, we need to multiply the result by 2, as we divided it by 2 before.
// --- This can be done efficiently by adding the result to itself.
// -- Then, we need to add the least significant bit that was shifted out.
// --- We can convert the least significant bit to float, and add it to the result.
Operand lsb = Local(OperandType.I64);
Operand half = Local(OperandType.I64);
Operand lsbF = Local(dest.Type);
node = nodes.AddAfter(node, Operation(Instruction.Copy, lsb, source));
node = nodes.AddAfter(node, Operation(Instruction.Copy, half, source));
node = nodes.AddAfter(node, Operation(Instruction.BitwiseAnd, lsb, lsb, Const(1L)));
node = nodes.AddAfter(node, Operation(Instruction.ShiftRightUI, half, half, Const(1)));
node = nodes.AddAfter(node, Operation(Instruction.ConvertToFP, lsbF, lsb));
node = nodes.AddAfter(node, Operation(Instruction.ConvertToFP, dest, half));
node = nodes.AddAfter(node, Operation(Instruction.Add, dest, dest, dest));
nodes.AddAfter(node, Operation(Instruction.Add, dest, dest, lsbF));
}
Delete(nodes, currentNode);
}
private static void GenerateNegate(IntrusiveList<Operation> nodes, Operation node)
{
// There's no SSE FP negate instruction, so we need to transform that into
// a XOR of the value to be negated with a mask with the highest bit set.
// This also produces -0 for a negation of the value 0.
Operand dest = node.Destination;
Operand source = node.GetSource(0);
Debug.Assert(dest.Type == OperandType.FP32 ||
dest.Type == OperandType.FP64, $"Invalid destination type \"{dest.Type}\".");
Operation currentNode = node;
Operand res = Local(dest.Type);
node = nodes.AddAfter(node, Operation(Instruction.VectorOne, res));
if (dest.Type == OperandType.FP32)
{
node = nodes.AddAfter(node, Operation(Intrinsic.X86Pslld, res, res, Const(31)));
}
else /* if (dest.Type == OperandType.FP64) */
{
node = nodes.AddAfter(node, Operation(Intrinsic.X86Psllq, res, res, Const(63)));
}
node = nodes.AddAfter(node, Operation(Intrinsic.X86Xorps, res, res, source));
nodes.AddAfter(node, Operation(Instruction.Copy, dest, res));
Delete(nodes, currentNode);
}
private static void GenerateVectorInsert8(IntrusiveList<Operation> nodes, Operation node)
{
// Handle vector insertion, when SSE 4.1 is not supported.
Operand dest = node.Destination;
Operand src1 = node.GetSource(0); // Vector
Operand src2 = node.GetSource(1); // Value
Operand src3 = node.GetSource(2); // Index
Debug.Assert(src3.Kind == OperandKind.Constant);
byte index = src3.AsByte();
Debug.Assert(index < 16);
Operation currentNode = node;
Operand temp1 = Local(OperandType.I32);
Operand temp2 = Local(OperandType.I32);
node = nodes.AddAfter(node, Operation(Instruction.Copy, temp2, src2));
Operation vextOp = Operation(Instruction.VectorExtract16, temp1, src1, Const(index >> 1));
node = nodes.AddAfter(node, vextOp);
if ((index & 1) != 0)
{
node = nodes.AddAfter(node, Operation(Instruction.ZeroExtend8, temp1, temp1));
node = nodes.AddAfter(node, Operation(Instruction.ShiftLeft, temp2, temp2, Const(8)));
node = nodes.AddAfter(node, Operation(Instruction.BitwiseOr, temp1, temp1, temp2));
}
else
{
node = nodes.AddAfter(node, Operation(Instruction.ZeroExtend8, temp2, temp2));
node = nodes.AddAfter(node, Operation(Instruction.BitwiseAnd, temp1, temp1, Const(0xff00)));
node = nodes.AddAfter(node, Operation(Instruction.BitwiseOr, temp1, temp1, temp2));
}
Operation vinsOp = Operation(Instruction.VectorInsert16, dest, src1, temp1, Const(index >> 1));
nodes.AddAfter(node, vinsOp);
Delete(nodes, currentNode);
}
protected static Operand AddXmmCopy(IntrusiveList<Operation> nodes, Operation node, Operand source)
{
Operand temp = Local(source.Type);
Operand intConst = AddCopy(nodes, node, GetIntConst(source));
Operation copyOp = Operation(Instruction.VectorCreateScalar, temp, intConst);
nodes.AddBefore(node, copyOp);
return temp;
}
protected static Operand AddCopy(IntrusiveList<Operation> nodes, Operation node, Operand source)
{
Operand temp = Local(source.Type);
Operation copyOp = Operation(Instruction.Copy, temp, source);
nodes.AddBefore(node, copyOp);
return temp;
}
private static Operand GetIntConst(Operand value)
{
if (value.Type == OperandType.FP32)
{
return Const(value.AsInt32());
}
else if (value.Type == OperandType.FP64)
{
return Const(value.AsInt64());
}
return value;
}
protected static void Delete(IntrusiveList<Operation> nodes, Operation node)
{
node.Destination = default;
for (int index = 0; index < node.SourcesCount; index++)
{
node.SetSource(index, default);
}
nodes.Remove(node);
}
protected static Operand Gpr(X86Register register, OperandType type)
{
return Register((int)register, RegisterType.Integer, type);
}
protected static Operand Xmm(X86Register register, OperandType type)
{
return Register((int)register, RegisterType.Vector, type);
}
private static bool IsSameOperandDestSrc1(Operation operation)
{
switch (operation.Instruction)
{
case Instruction.Add:
return !HardwareCapabilities.SupportsVexEncoding && !operation.Destination.Type.IsInteger();
case Instruction.Multiply:
case Instruction.Subtract:
return !HardwareCapabilities.SupportsVexEncoding || operation.Destination.Type.IsInteger();
case Instruction.BitwiseAnd:
case Instruction.BitwiseExclusiveOr:
case Instruction.BitwiseNot:
case Instruction.BitwiseOr:
case Instruction.ByteSwap:
case Instruction.Negate:
case Instruction.RotateRight:
case Instruction.ShiftLeft:
case Instruction.ShiftRightSI:
case Instruction.ShiftRightUI:
return true;
case Instruction.Divide:
return !HardwareCapabilities.SupportsVexEncoding && !operation.Destination.Type.IsInteger();
case Instruction.VectorInsert:
case Instruction.VectorInsert16:
case Instruction.VectorInsert8:
return !HardwareCapabilities.SupportsVexEncoding;
case Instruction.Extended:
return IsIntrinsicSameOperandDestSrc1(operation);
}
return IsVexSameOperandDestSrc1(operation);
}
private static bool IsIntrinsicSameOperandDestSrc1(Operation operation)
{
IntrinsicInfo info = IntrinsicTable.GetInfo(operation.Intrinsic);
return info.Type == IntrinsicType.Crc32 || info.Type == IntrinsicType.Fma || IsVexSameOperandDestSrc1(operation);
}
private static bool IsVexSameOperandDestSrc1(Operation operation)
{
if (IsIntrinsic(operation.Instruction))
{
IntrinsicInfo info = IntrinsicTable.GetInfo(operation.Intrinsic);
bool hasVex = HardwareCapabilities.SupportsVexEncoding && Assembler.SupportsVexPrefix(info.Inst);
bool isUnary = operation.SourcesCount < 2;
bool hasVecDest = operation.Destination != default && operation.Destination.Type == OperandType.V128;
return !hasVex && !isUnary && hasVecDest;
}
return false;
}
private static bool HasConstSrc1(Instruction inst)
{
switch (inst)
{
case Instruction.Copy:
case Instruction.LoadArgument:
case Instruction.Spill:
case Instruction.SpillArg:
return true;
}
return false;
}
private static bool HasConstSrc2(Instruction inst)
{
switch (inst)
{
case Instruction.Add:
case Instruction.BitwiseAnd:
case Instruction.BitwiseExclusiveOr:
case Instruction.BitwiseOr:
case Instruction.BranchIf:
case Instruction.Compare:
case Instruction.Multiply:
case Instruction.RotateRight:
case Instruction.ShiftLeft:
case Instruction.ShiftRightSI:
case Instruction.ShiftRightUI:
case Instruction.Store:
case Instruction.Store16:
case Instruction.Store8:
case Instruction.Subtract:
case Instruction.VectorExtract:
case Instruction.VectorExtract16:
case Instruction.VectorExtract8:
return true;
}
return false;
}
private static bool IsCommutative(Operation operation)
{
switch (operation.Instruction)
{
case Instruction.Add:
case Instruction.BitwiseAnd:
case Instruction.BitwiseExclusiveOr:
case Instruction.BitwiseOr:
case Instruction.Multiply:
return true;
case Instruction.BranchIf:
case Instruction.Compare:
{
Operand comp = operation.GetSource(2);
Debug.Assert(comp.Kind == OperandKind.Constant);
var compType = (Comparison)comp.AsInt32();
return compType == Comparison.Equal || compType == Comparison.NotEqual;
}
}
return false;
}
private static bool IsIntrinsic(Instruction inst)
{
return inst == Instruction.Extended;
}
private static bool IsXmmIntrinsic(Operation operation)
{
if (operation.Instruction != Instruction.Extended)
{
return false;
}
IntrinsicInfo info = IntrinsicTable.GetInfo(operation.Intrinsic);
return info.Type != IntrinsicType.Crc32;
}
}
}