1 files changed, 330 insertions, 0 deletions
diff --git a/src/Ryujinx.Graphics.Shader/StructuredIr/StructuredProgramContext.cs b/src/Ryujinx.Graphics.Shader/StructuredIr/StructuredProgramContext.cs
new file mode 100644
index 00000000..68bbdeb1
--- /dev/null
+++ b/src/Ryujinx.Graphics.Shader/StructuredIr/StructuredProgramContext.cs
@@ -0,0 +1,330 @@
+using Ryujinx.Graphics.Shader.IntermediateRepresentation;
+using Ryujinx.Graphics.Shader.Translation;
+using System.Collections.Generic;
+using System.Linq;
+using System.Numerics;
+
+using static Ryujinx.Graphics.Shader.StructuredIr.AstHelper;
+
+namespace Ryujinx.Graphics.Shader.StructuredIr
+{
+    class StructuredProgramContext
+    {
+        private HashSet<BasicBlock> _loopTails;
+
+        private Stack<(AstBlock Block, int CurrEndIndex, int LoopEndIndex)> _blockStack;
+
+        private Dictionary<Operand, AstOperand> _localsMap;
+
+        private Dictionary<int, AstAssignment> _gotoTempAsgs;
+
+        private List<GotoStatement> _gotos;
+
+        private AstBlock _currBlock;
+
+        private int _currEndIndex;
+        private int _loopEndIndex;
+
+        public StructuredFunction CurrentFunction { get; private set; }
+
+        public StructuredProgramInfo Info { get; }
+
+        public ShaderConfig Config { get; }
+
+        public StructuredProgramContext(ShaderConfig config)
+        {
+            Info = new StructuredProgramInfo();
+
+            Config = config;
+
+            if (config.GpPassthrough)
+            {
+                int passthroughAttributes = config.PassthroughAttributes;
+                while (passthroughAttributes != 0)
+                {
+                    int index = BitOperations.TrailingZeroCount(passthroughAttributes);
+
+                    Info.IoDefinitions.Add(new IoDefinition(StorageKind.Input, IoVariable.UserDefined, index));
+
+                    passthroughAttributes &= ~(1 << index);
+                }
+
+                Info.IoDefinitions.Add(new IoDefinition(StorageKind.Input, IoVariable.Position));
+                Info.IoDefinitions.Add(new IoDefinition(StorageKind.Input, IoVariable.PointSize));
+                Info.IoDefinitions.Add(new IoDefinition(StorageKind.Input, IoVariable.ClipDistance));
+            }
+            else if (config.Stage == ShaderStage.Fragment)
+            {
+                // Potentially used for texture coordinate scaling.
+                Info.IoDefinitions.Add(new IoDefinition(StorageKind.Input, IoVariable.FragmentCoord));
+            }
+        }
+
+        public void EnterFunction(
+            int blocksCount,
+            string name,
+            AggregateType returnType,
+            AggregateType[] inArguments,
+            AggregateType[] outArguments)
+        {
+            _loopTails = new HashSet<BasicBlock>();
+
+            _blockStack = new Stack<(AstBlock, int, int)>();
+
+            _localsMap = new Dictionary<Operand, AstOperand>();
+
+            _gotoTempAsgs = new Dictionary<int, AstAssignment>();
+
+            _gotos = new List<GotoStatement>();
+
+            _currBlock = new AstBlock(AstBlockType.Main);
+
+            _currEndIndex = blocksCount;
+            _loopEndIndex = blocksCount;
+
+            CurrentFunction = new StructuredFunction(_currBlock, name, returnType, inArguments, outArguments);
+        }
+
+        public void LeaveFunction()
+        {
+            Info.Functions.Add(CurrentFunction);
+        }
+
+        public void EnterBlock(BasicBlock block)
+        {
+            while (_currEndIndex == block.Index)
+            {
+                (_currBlock, _currEndIndex, _loopEndIndex) = _blockStack.Pop();
+            }
+
+            if (_gotoTempAsgs.TryGetValue(block.Index, out AstAssignment gotoTempAsg))
+            {
+                AddGotoTempReset(block, gotoTempAsg);
+            }
+
+            LookForDoWhileStatements(block);
+        }
+
+        public void LeaveBlock(BasicBlock block, Operation branchOp)
+        {
+            LookForIfStatements(block, branchOp);
+        }
+
+        private void LookForDoWhileStatements(BasicBlock block)
+        {
+            // Check if we have any predecessor whose index is greater than the
+            // current block, this indicates a loop.
+            bool done = false;
+
+            foreach (BasicBlock predecessor in block.Predecessors.OrderByDescending(x => x.Index))
+            {
+                // If not a loop, break.
+                if (predecessor.Index < block.Index)
+                {
+                    break;
+                }
+
+                // Check if we can create a do-while loop here (only possible if the loop end
+                // falls inside the current scope), if not add a goto instead.
+                if (predecessor.Index < _currEndIndex && !done)
+                {
+                    // Create do-while loop block. We must avoid inserting a goto at the end
+                    // of the loop later, when the tail block is processed. So we add the predecessor
+                    // to a list of loop tails to prevent it from being processed later.
+                    Operation branchOp = (Operation)predecessor.GetLastOp();
+
+                    NewBlock(AstBlockType.DoWhile, branchOp, predecessor.Index + 1);
+
+                    _loopTails.Add(predecessor);
+
+                    done = true;
+                }
+                else
+                {
+                    // Failed to create loop. Since this block is the loop head, we reset the
+                    // goto condition variable here. The variable is always reset on the jump
+                    // target, and this block is the jump target for some loop.
+                    AddGotoTempReset(block, GetGotoTempAsg(block.Index));
+
+                    break;
+                }
+            }
+        }
+
+        private void LookForIfStatements(BasicBlock block, Operation branchOp)
+        {
+            if (block.Branch == null)
+            {
+                return;
+            }
+
+            // We can only enclose the "if" when the branch lands before
+            // the end of the current block. If the current enclosing block
+            // is not a loop, then we can also do so if the branch lands
+            // right at the end of the current block. When it is a loop,
+            // this is not valid as the loop condition would be evaluated,
+            // and it could erroneously jump back to the start of the loop.
+            bool inRange =
+                block.Branch.Index <  _currEndIndex ||
+               (block.Branch.Index == _currEndIndex && block.Branch.Index < _loopEndIndex);
+
+            bool isLoop = block.Branch.Index <= block.Index;
+
+            if (inRange && !isLoop)
+            {
+                NewBlock(AstBlockType.If, branchOp, block.Branch.Index);
+            }
+            else if (!_loopTails.Contains(block))
+            {
+                AstAssignment gotoTempAsg = GetGotoTempAsg(block.Branch.Index);
+
+                // We use DoWhile type here, as the condition should be true for
+                // unconditional branches, or it should jump if the condition is true otherwise.
+                IAstNode cond = GetBranchCond(AstBlockType.DoWhile, branchOp);
+
+                AddNode(Assign(gotoTempAsg.Destination, cond));
+
+                AstOperation branch = new AstOperation(branchOp.Inst);
+
+                AddNode(branch);
+
+                GotoStatement gotoStmt = new GotoStatement(branch, gotoTempAsg, isLoop);
+
+                _gotos.Add(gotoStmt);
+            }
+        }
+
+        private AstAssignment GetGotoTempAsg(int index)
+        {
+            if (_gotoTempAsgs.TryGetValue(index, out AstAssignment gotoTempAsg))
+            {
+                return gotoTempAsg;
+            }
+
+            AstOperand gotoTemp = NewTemp(AggregateType.Bool);
+
+            gotoTempAsg = Assign(gotoTemp, Const(IrConsts.False));
+
+            _gotoTempAsgs.Add(index, gotoTempAsg);
+
+            return gotoTempAsg;
+        }
+
+        private void AddGotoTempReset(BasicBlock block, AstAssignment gotoTempAsg)
+        {
+            // If it was already added, we don't need to add it again.
+            if (gotoTempAsg.Parent != null)
+            {
+                return;
+            }
+
+            AddNode(gotoTempAsg);
+
+            // For block 0, we don't need to add the extra "reset" at the beginning,
+            // because it is already the first node to be executed on the shader,
+            // so it is reset to false by the "local" assignment anyway.
+            if (block.Index != 0)
+            {
+                CurrentFunction.MainBlock.AddFirst(Assign(gotoTempAsg.Destination, Const(IrConsts.False)));
+            }
+        }
+
+        private void NewBlock(AstBlockType type, Operation branchOp, int endIndex)
+        {
+            NewBlock(type, GetBranchCond(type, branchOp), endIndex);
+        }
+
+        private void NewBlock(AstBlockType type, IAstNode cond, int endIndex)
+        {
+            AstBlock childBlock = new AstBlock(type, cond);
+
+            AddNode(childBlock);
+
+            _blockStack.Push((_currBlock, _currEndIndex, _loopEndIndex));
+
+            _currBlock    = childBlock;
+            _currEndIndex = endIndex;
+
+            if (type == AstBlockType.DoWhile)
+            {
+                _loopEndIndex = endIndex;
+            }
+        }
+
+        private IAstNode GetBranchCond(AstBlockType type, Operation branchOp)
+        {
+            IAstNode cond;
+
+            if (branchOp.Inst == Instruction.Branch)
+            {
+                // If the branch is not conditional, the condition is a constant.
+                // For if it's false (always jump over, if block never executed).
+                // For loops it's always true (always loop).
+                cond = Const(type == AstBlockType.If ? IrConsts.False : IrConsts.True);
+            }
+            else
+            {
+                cond = GetOperand(branchOp.GetSource(0));
+
+                Instruction invInst = type == AstBlockType.If
+                    ? Instruction.BranchIfTrue
+                    : Instruction.BranchIfFalse;
+
+                if (branchOp.Inst == invInst)
+                {
+                    cond = new AstOperation(Instruction.LogicalNot, cond);
+                }
+            }
+
+            return cond;
+        }
+
+        public void AddNode(IAstNode node)
+        {
+            _currBlock.Add(node);
+        }
+
+        public GotoStatement[] GetGotos()
+        {
+            return _gotos.ToArray();
+        }
+
+        public AstOperand NewTemp(AggregateType type)
+        {
+            AstOperand newTemp = Local(type);
+
+            CurrentFunction.Locals.Add(newTemp);
+
+            return newTemp;
+        }
+
+        public AstOperand GetOperand(Operand operand)
+        {
+            if (operand == null)
+            {
+                return null;
+            }
+
+            if (operand.Type != OperandType.LocalVariable)
+            {
+                if (operand.Type == OperandType.ConstantBuffer)
+                {
+                    Config.SetUsedConstantBuffer(operand.GetCbufSlot());
+                }
+
+                return new AstOperand(operand);
+            }
+
+            if (!_localsMap.TryGetValue(operand, out AstOperand astOperand))
+            {
+                astOperand = new AstOperand(operand);
+
+                _localsMap.Add(operand, astOperand);
+
+                CurrentFunction.Locals.Add(astOperand);
+            }
+
+            return astOperand;
+        }
+    }
+}
+\ No newline at end of file