Rewrite shader decoding stage (#2698)

* Rewrite shader decoding stage

* Fix P2R constant buffer encoding

* Fix PSET/PSETP

* PR feedback

* Log unimplemented shader instructions

* Implement NOP

* Remove using

* PR feedback

Ryujinx.Graphics.Shader/Instructions/InstEmitFlowControl.cs

@@ -0,0 +1,238 @@
+using Ryujinx.Graphics.Shader.Decoders;
+using Ryujinx.Graphics.Shader.IntermediateRepresentation;
+using Ryujinx.Graphics.Shader.Translation;
+using System.Collections.Generic;
+using System.Linq;
+
+using static Ryujinx.Graphics.Shader.Instructions.InstEmitHelper;
+using static Ryujinx.Graphics.Shader.IntermediateRepresentation.OperandHelper;
+
+namespace Ryujinx.Graphics.Shader.Instructions
+{
+    static partial class InstEmit
+    {
+        public static void Bra(EmitterContext context)
+        {
+            InstBra op = context.GetOp<InstBra>();
+
+            EmitBranch(context, context.CurrBlock.Successors[^1].Address);
+        }
+
+        public static void Brk(EmitterContext context)
+        {
+            InstBrk op = context.GetOp<InstBrk>();
+
+            EmitBrkOrSync(context);
+        }
+
+        public static void Brx(EmitterContext context)
+        {
+            InstBrx op = context.GetOp<InstBrx>();
+            InstOp currOp = context.CurrOp;
+            int startIndex = context.CurrBlock.HasNext() ? 1 : 0;
+
+            if (context.CurrBlock.Successors.Count <= startIndex)
+            {
+                context.Config.GpuAccessor.Log($"Failed to find targets for BRX instruction at 0x{currOp.Address:X}.");
+                return;
+            }
+
+            int offset = (int)currOp.GetAbsoluteAddress();
+
+            Operand address = context.IAdd(Register(op.SrcA, RegisterType.Gpr), Const(offset));
+
+            // Sorting the target addresses in descending order improves the code,
+            // since it will always check the most distant targets first, then the
+            // near ones. This can be easily transformed into if/else statements.
+            var sortedTargets = context.CurrBlock.Successors.Skip(startIndex).OrderByDescending(x => x.Address);
+
+            Block lastTarget = sortedTargets.LastOrDefault();
+
+            foreach (Block possibleTarget in sortedTargets)
+            {
+                Operand label = context.GetLabel(possibleTarget.Address);
+
+                if (possibleTarget != lastTarget)
+                {
+                    context.BranchIfTrue(label, context.ICompareEqual(address, Const((int)possibleTarget.Address)));
+                }
+                else
+                {
+                    context.Branch(label);
+                }
+            }
+        }
+
+        public static void Cal(EmitterContext context)
+        {
+            InstCal op = context.GetOp<InstCal>();
+
+            context.Call(context.GetFunctionId(context.CurrOp.GetAbsoluteAddress()), false);
+        }
+
+        public static void Exit(EmitterContext context)
+        {
+            InstExit op = context.GetOp<InstExit>();
+
+            if (context.IsNonMain)
+            {
+                context.Config.GpuAccessor.Log("Invalid exit on non-main function.");
+                return;
+            }
+
+            // TODO: Figure out how this is supposed to work in the
+            // presence of other condition codes.
+            if (op.Ccc == Ccc.T)
+            {
+                context.Return();
+            }
+        }
+
+        public static void Kil(EmitterContext context)
+        {
+            InstKil op = context.GetOp<InstKil>();
+
+            context.Discard();
+        }
+
+        public static void Pbk(EmitterContext context)
+        {
+            InstPbk op = context.GetOp<InstPbk>();
+
+            EmitPbkOrSsy(context);
+        }
+
+        public static void Ret(EmitterContext context)
+        {
+            InstRet op = context.GetOp<InstRet>();
+
+            if (context.IsNonMain)
+            {
+                context.Return();
+            }
+            else
+            {
+                context.Config.GpuAccessor.Log("Invalid return on main function.");
+            }
+        }
+
+        public static void Ssy(EmitterContext context)
+        {
+            InstSsy op = context.GetOp<InstSsy>();
+
+            EmitPbkOrSsy(context);
+        }
+
+        public static void Sync(EmitterContext context)
+        {
+            InstSync op = context.GetOp<InstSync>();
+
+            EmitBrkOrSync(context);
+        }
+
+        private static void EmitPbkOrSsy(EmitterContext context)
+        {
+            var consumers = context.CurrBlock.PushOpCodes.First(x => x.Op.Address == context.CurrOp.Address).Consumers;
+
+            foreach (KeyValuePair<Block, Operand> kv in consumers)
+            {
+                Block consumerBlock = kv.Key;
+                Operand local = kv.Value;
+
+                int id = consumerBlock.SyncTargets[context.CurrOp.Address].PushOpId;
+
+                context.Copy(local, Const(id));
+            }
+        }
+
+        private static void EmitBrkOrSync(EmitterContext context)
+        {
+            var targets = context.CurrBlock.SyncTargets;
+
+            if (targets.Count == 1)
+            {
+                // If we have only one target, then the SSY/PBK is basically
+                // a branch, we can produce better codegen for this case.
+                EmitBranch(context, targets.Values.First().PushOpInfo.Op.GetAbsoluteAddress());
+            }
+            else
+            {
+                // TODO: Support CC here aswell (condition).
+                foreach (SyncTarget target in targets.Values)
+                {
+                    PushOpInfo pushOpInfo = target.PushOpInfo;
+
+                    Operand label = context.GetLabel(pushOpInfo.Op.GetAbsoluteAddress());
+                    Operand local = pushOpInfo.Consumers[context.CurrBlock];
+
+                    context.BranchIfTrue(label, context.ICompareEqual(local, Const(target.PushOpId)));
+                }
+            }
+        }
+
+        private static void EmitBranch(EmitterContext context, ulong address)
+        {
+            InstOp op = context.CurrOp;
+            InstConditional opCond = new InstConditional(op.RawOpCode);
+
+            // If we're branching to the next instruction, then the branch
+            // is useless and we can ignore it.
+            if (address == op.Address + 8)
+            {
+                return;
+            }
+
+            Operand label = context.GetLabel(address);
+
+            Operand pred = Register(opCond.Pred, RegisterType.Predicate);
+
+            if (opCond.Ccc != Ccc.T)
+            {
+                Operand cond = GetCondition(context, opCond.Ccc);
+
+                if (opCond.Pred == RegisterConsts.PredicateTrueIndex)
+                {
+                    pred = cond;
+                }
+                else if (opCond.PredInv)
+                {
+                    pred = context.BitwiseAnd(context.BitwiseNot(pred), cond);
+                }
+                else
+                {
+                    pred = context.BitwiseAnd(pred, cond);
+                }
+
+                context.BranchIfTrue(label, pred);
+            }
+            else if (opCond.Pred == RegisterConsts.PredicateTrueIndex)
+            {
+                context.Branch(label);
+            }
+            else if (opCond.PredInv)
+            {
+                context.BranchIfFalse(label, pred);
+            }
+            else
+            {
+                context.BranchIfTrue(label, pred);
+            }
+        }
+
+        private static Operand GetCondition(EmitterContext context, Ccc cond)
+        {
+            // TODO: More condition codes, figure out how they work.
+            switch (cond)
+            {
+                case Ccc.Eq:
+                case Ccc.Equ:
+                    return GetZF();
+                case Ccc.Ne:
+                case Ccc.Neu:
+                    return context.BitwiseNot(GetZF());
+            }
+
+            return Const(IrConsts.True);
+        }
+    }
+}