Ryujinx-uplift/ARMeilleure/CodeGen/X86/X86Optimizer.cs
riperiperi 8226997bc7
CodeGen Optimisations (LSRA and Translator) (#978)
* Start of JIT garbage collection improvements

- thread static pool for Operand, MemoryOperand, Operation
- Operands and Operations are always to be constructed via their static
helper classes, so they can be pooled.
- removing LinkedList from Node for sources/destinations (replaced with
List<>s for now, but probably could do arrays since size is bounded)
- removing params constructors from Node
- LinkedList<> to List<> with Clear() for Operand assignments/uses
- ThreadStaticPool is very simple and basically just exists for the
purpose of our specific translation allocation problem. Right now it
will stay at the worst case allocation count for that thread (so far) -
the pool can never shrink.

- Still some cases of Operand[] that haven't been removed yet. Will need
to evaluate them (eg. is there a reasonable max number of params for
Calls?)

* ConcurrentStack instead of ConcurrentQueue for Rejit

* Optimize some parts of LSRA

- BitMap now operates on 64-bit int rather than 32-bit
- BitMap is now pooled in a ThreadStatic pool (within lrsa)
- BitMap now is now its own iterator. Marginally speeds up iterating
through the bits.
- A few cases where enumerators were generated have been converted to
forms that generate less garbage.
- New data structure for sorting _usePositions in LiveIntervals. Much
faster split, NextUseAfter, initial insertion. Random insertion is
slightly slower.
- That last one is WIP since you need to insert the values backwards. It
would be ideal if it just flipped it for you, uncomplicating things on
the caller side.

* Use a static pool of thread static pools. (yes.)

Prevents each execution thread creating its own lowCq pool and making me cry.

* Move constant value to top, change naming convention.

* Fix iteration of memory operands.

* Increase max thread count.

* Address Feedback
2020-03-18 22:44:32 +11:00

253 lines
8.3 KiB
C#

using ARMeilleure.CodeGen.Optimizations;
using ARMeilleure.IntermediateRepresentation;
using ARMeilleure.Translation;
using static ARMeilleure.IntermediateRepresentation.OperandHelper;
using static ARMeilleure.IntermediateRepresentation.OperationHelper;
namespace ARMeilleure.CodeGen.X86
{
static class X86Optimizer
{
public static void RunPass(ControlFlowGraph cfg)
{
for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
{
Node nextNode;
for (Node node = block.Operations.First; node != null; node = nextNode)
{
nextNode = node.ListNext;
if (!(node is Operation operation))
{
continue;
}
// Insert copies for constants that can't fit on a 32-bits immediate.
// Doing this early unblocks a few optimizations.
if (operation.Instruction == Instruction.Add)
{
Operand src1 = operation.GetSource(0);
Operand src2 = operation.GetSource(1);
if (src1.Kind == OperandKind.Constant && CodeGenCommon.IsLongConst(src1))
{
Operand temp = Local(src1.Type);
Operation copyOp = Operation(Instruction.Copy, temp, src1);
block.Operations.AddBefore(operation, copyOp);
operation.SetSource(0, temp);
}
if (src2.Kind == OperandKind.Constant && CodeGenCommon.IsLongConst(src2))
{
Operand temp = Local(src2.Type);
Operation copyOp = Operation(Instruction.Copy, temp, src2);
block.Operations.AddBefore(operation, copyOp);
operation.SetSource(1, temp);
}
}
// Try to fold something like:
// shl rbx, 2
// add rax, rbx
// add rax, 0xcafe
// mov rax, [rax]
// Into:
// mov rax, [rax+rbx*4+0xcafe]
if (IsMemoryLoadOrStore(operation.Instruction))
{
OperandType type;
if (operation.Destination != null)
{
type = operation.Destination.Type;
}
else
{
type = operation.GetSource(1).Type;
}
MemoryOperand memOp = GetMemoryOperandOrNull(operation.GetSource(0), type);
if (memOp != null)
{
operation.SetSource(0, memOp);
}
}
}
}
Optimizer.RemoveUnusedNodes(cfg);
}
private static MemoryOperand GetMemoryOperandOrNull(Operand addr, OperandType type)
{
Operand baseOp = addr;
// First we check if the address is the result of a local X with 32-bits immediate
// addition. If that is the case, then the baseOp is X, and the memory operand immediate
// becomes the addition immediate. Otherwise baseOp keeps being the address.
int imm = GetConstOp(ref baseOp);
// Now we check if the baseOp is the result of a local Y with a local Z addition.
// If that is the case, we now set baseOp to Y and indexOp to Z. We further check
// if Z is the result of a left shift of local W by a value >= 0 and <= 3, if that
// is the case, we set indexOp to W and adjust the scale value of the memory operand
// to match that of the left shift.
// There is one missed case, which is the address being a shift result, but this is
// probably not worth optimizing as it should never happen.
(Operand indexOp, Multiplier scale) = GetIndexOp(ref baseOp);
// If baseOp is still equal to address, then there's nothing that can be optimized.
if (baseOp == addr)
{
return null;
}
return MemoryOp(type, baseOp, indexOp, scale, imm);
}
private static int GetConstOp(ref Operand baseOp)
{
Operation operation = GetAsgOpWithInst(baseOp, Instruction.Add);
if (operation == null)
{
return 0;
}
Operand src1 = operation.GetSource(0);
Operand src2 = operation.GetSource(1);
Operand constOp;
Operand otherOp;
if (src1.Kind == OperandKind.Constant && src2.Kind == OperandKind.LocalVariable)
{
constOp = src1;
otherOp = src2;
}
else if (src1.Kind == OperandKind.LocalVariable && src2.Kind == OperandKind.Constant)
{
constOp = src2;
otherOp = src1;
}
else
{
return 0;
}
// If we have addition by 64-bits constant, then we can't optimize it further,
// as we can't encode a 64-bits immediate on the memory operand.
if (CodeGenCommon.IsLongConst(constOp))
{
return 0;
}
baseOp = otherOp;
return constOp.AsInt32();
}
private static (Operand, Multiplier) GetIndexOp(ref Operand baseOp)
{
Operand indexOp = null;
Multiplier scale = Multiplier.x1;
Operation addOp = GetAsgOpWithInst(baseOp, Instruction.Add);
if (addOp == null)
{
return (indexOp, scale);
}
Operand src1 = addOp.GetSource(0);
Operand src2 = addOp.GetSource(1);
if (src1.Kind != OperandKind.LocalVariable || src2.Kind != OperandKind.LocalVariable)
{
return (indexOp, scale);
}
baseOp = src1;
indexOp = src2;
Operation shlOp = GetAsgOpWithInst(src1, Instruction.ShiftLeft);
bool indexOnSrc2 = false;
if (shlOp == null)
{
shlOp = GetAsgOpWithInst(src2, Instruction.ShiftLeft);
indexOnSrc2 = true;
}
if (shlOp != null)
{
Operand shSrc = shlOp.GetSource(0);
Operand shift = shlOp.GetSource(1);
if (shSrc.Kind == OperandKind.LocalVariable && shift.Kind == OperandKind.Constant && shift.Value <= 3)
{
scale = shift.Value switch
{
1 => Multiplier.x2,
2 => Multiplier.x4,
3 => Multiplier.x8,
_ => Multiplier.x1
};
baseOp = indexOnSrc2 ? src1 : src2;
indexOp = shSrc;
}
}
return (indexOp, scale);
}
private static Operation GetAsgOpWithInst(Operand op, Instruction inst)
{
// If we have multiple assignments, folding is not safe
// as the value may be different depending on the
// control flow path.
if (op.Assignments.Count != 1)
{
return null;
}
Node asgOp = op.Assignments[0];
if (!(asgOp is Operation operation))
{
return null;
}
if (operation.Instruction != inst)
{
return null;
}
return operation;
}
private static bool IsMemoryLoadOrStore(Instruction inst)
{
return inst == Instruction.Load ||
inst == Instruction.Load16 ||
inst == Instruction.Load8 ||
inst == Instruction.Store ||
inst == Instruction.Store16 ||
inst == Instruction.Store8;
}
}
}