Ryujinx/Ryujinx.Graphics.Shader/Decoders/Decoder.cs
gdkchan 7f8a3541eb
Fix decoding of block after shader BRA.CC instructions without predicate (#3472)
* Fix decoding of block after BRA.CC instructions without predicate

* Shader cache version bump
2022-07-23 11:53:14 -03:00

737 lines
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27 KiB
C#

using Ryujinx.Graphics.Shader.Translation;
using System;
using System.Collections.Generic;
using System.Linq;
using System.Runtime.CompilerServices;
using static Ryujinx.Graphics.Shader.IntermediateRepresentation.OperandHelper;
namespace Ryujinx.Graphics.Shader.Decoders
{
static class Decoder
{
public static DecodedProgram Decode(ShaderConfig config, ulong startAddress)
{
Queue<DecodedFunction> functionsQueue = new Queue<DecodedFunction>();
Dictionary<ulong, DecodedFunction> functionsVisited = new Dictionary<ulong, DecodedFunction>();
DecodedFunction EnqueueFunction(ulong address)
{
if (!functionsVisited.TryGetValue(address, out DecodedFunction function))
{
functionsVisited.Add(address, function = new DecodedFunction(address));
functionsQueue.Enqueue(function);
}
return function;
}
DecodedFunction mainFunction = EnqueueFunction(0);
while (functionsQueue.TryDequeue(out DecodedFunction currentFunction))
{
List<Block> blocks = new List<Block>();
Queue<Block> workQueue = new Queue<Block>();
Dictionary<ulong, Block> visited = new Dictionary<ulong, Block>();
Block GetBlock(ulong blkAddress)
{
if (!visited.TryGetValue(blkAddress, out Block block))
{
block = new Block(blkAddress);
workQueue.Enqueue(block);
visited.Add(blkAddress, block);
}
return block;
}
GetBlock(currentFunction.Address);
bool hasNewTarget;
do
{
while (workQueue.TryDequeue(out Block currBlock))
{
// Check if the current block is inside another block.
if (BinarySearch(blocks, currBlock.Address, out int nBlkIndex))
{
Block nBlock = blocks[nBlkIndex];
if (nBlock.Address == currBlock.Address)
{
throw new InvalidOperationException("Found duplicate block address on the list.");
}
nBlock.Split(currBlock);
blocks.Insert(nBlkIndex + 1, currBlock);
continue;
}
// If we have a block after the current one, set the limit address.
ulong limitAddress = ulong.MaxValue;
if (nBlkIndex != blocks.Count)
{
Block nBlock = blocks[nBlkIndex];
int nextIndex = nBlkIndex + 1;
if (nBlock.Address < currBlock.Address && nextIndex < blocks.Count)
{
limitAddress = blocks[nextIndex].Address;
}
else if (nBlock.Address > currBlock.Address)
{
limitAddress = blocks[nBlkIndex].Address;
}
}
FillBlock(config, currBlock, limitAddress, startAddress);
if (currBlock.OpCodes.Count != 0)
{
// We should have blocks for all possible branch targets,
// including those from PBK/PCNT/SSY instructions.
foreach (PushOpInfo pushOp in currBlock.PushOpCodes)
{
GetBlock(pushOp.Op.GetAbsoluteAddress());
}
// Set child blocks. "Branch" is the block the branch instruction
// points to (when taken), "Next" is the block at the next address,
// executed when the branch is not taken. For Unconditional Branches
// or end of program, Next is null.
InstOp lastOp = currBlock.GetLastOp();
if (lastOp.Name == InstName.Cal)
{
EnqueueFunction(lastOp.GetAbsoluteAddress()).AddCaller(currentFunction);
}
else if (lastOp.Name == InstName.Bra)
{
Block succBlock = GetBlock(lastOp.GetAbsoluteAddress());
currBlock.Successors.Add(succBlock);
succBlock.Predecessors.Add(currBlock);
}
if (!IsUnconditionalBranch(ref lastOp))
{
Block succBlock = GetBlock(currBlock.EndAddress);
currBlock.Successors.Insert(0, succBlock);
succBlock.Predecessors.Add(currBlock);
}
}
// Insert the new block on the list (sorted by address).
if (blocks.Count != 0)
{
Block nBlock = blocks[nBlkIndex];
blocks.Insert(nBlkIndex + (nBlock.Address < currBlock.Address ? 1 : 0), currBlock);
}
else
{
blocks.Add(currBlock);
}
}
// Propagate SSY/PBK addresses into their uses (SYNC/BRK).
foreach (Block block in blocks.Where(x => x.PushOpCodes.Count != 0))
{
for (int pushOpIndex = 0; pushOpIndex < block.PushOpCodes.Count; pushOpIndex++)
{
PropagatePushOp(visited, block, pushOpIndex);
}
}
// Try to find targets for BRX (indirect branch) instructions.
hasNewTarget = FindBrxTargets(config, blocks, GetBlock);
// If we discovered new branch targets from the BRX instruction,
// we need another round of decoding to decode the new blocks.
// Additionally, we may have more SSY/PBK targets to propagate,
// and new BRX instructions.
}
while (hasNewTarget);
currentFunction.SetBlocks(blocks.ToArray());
}
return new DecodedProgram(mainFunction, functionsVisited);
}
private static bool BinarySearch(List<Block> blocks, ulong address, out int index)
{
index = 0;
int left = 0;
int right = blocks.Count - 1;
while (left <= right)
{
int size = right - left;
int middle = left + (size >> 1);
Block block = blocks[middle];
index = middle;
if (address >= block.Address && address < block.EndAddress)
{
return true;
}
if (address < block.Address)
{
right = middle - 1;
}
else
{
left = middle + 1;
}
}
return false;
}
private static void FillBlock(ShaderConfig config, Block block, ulong limitAddress, ulong startAddress)
{
IGpuAccessor gpuAccessor = config.GpuAccessor;
ulong address = block.Address;
int bufferOffset = 0;
ReadOnlySpan<ulong> buffer = ReadOnlySpan<ulong>.Empty;
InstOp op = default;
do
{
if (address + 7 >= limitAddress)
{
break;
}
// Ignore scheduling instructions, which are written every 32 bytes.
if ((address & 0x1f) == 0)
{
address += 8;
bufferOffset++;
continue;
}
if (bufferOffset >= buffer.Length)
{
buffer = gpuAccessor.GetCode(startAddress + address, 8);
bufferOffset = 0;
}
ulong opCode = buffer[bufferOffset++];
op = InstTable.GetOp(address, opCode);
if (op.Props.HasFlag(InstProps.TexB))
{
config.SetUsedFeature(FeatureFlags.Bindless);
}
if (op.Name == InstName.Ald || op.Name == InstName.Ast || op.Name == InstName.Ipa)
{
SetUserAttributeUses(config, op.Name, opCode);
}
else if (op.Name == InstName.Pbk || op.Name == InstName.Pcnt || op.Name == InstName.Ssy)
{
block.AddPushOp(op);
}
block.OpCodes.Add(op);
address += 8;
}
while (!op.Props.HasFlag(InstProps.Bra));
block.EndAddress = address;
}
private static void SetUserAttributeUses(ShaderConfig config, InstName name, ulong opCode)
{
int offset;
int count = 1;
bool isStore = false;
bool indexed = false;
bool perPatch = false;
if (name == InstName.Ast)
{
InstAst opAst = new InstAst(opCode);
count = (int)opAst.AlSize + 1;
offset = opAst.Imm11;
indexed = opAst.Phys;
perPatch = opAst.P;
isStore = true;
}
else if (name == InstName.Ald)
{
InstAld opAld = new InstAld(opCode);
count = (int)opAld.AlSize + 1;
offset = opAld.Imm11;
indexed = opAld.Phys;
perPatch = opAld.P;
isStore = opAld.O;
}
else /* if (name == InstName.Ipa) */
{
InstIpa opIpa = new InstIpa(opCode);
offset = opIpa.Imm10;
indexed = opIpa.Idx;
}
if (indexed)
{
if (isStore)
{
config.SetAllOutputUserAttributes();
}
else
{
config.SetAllInputUserAttributes();
}
}
else
{
for (int elemIndex = 0; elemIndex < count; elemIndex++)
{
int attr = offset + elemIndex * 4;
if (attr >= AttributeConsts.UserAttributeBase && attr < AttributeConsts.UserAttributeEnd)
{
int userAttr = attr - AttributeConsts.UserAttributeBase;
int index = userAttr / 16;
if (isStore)
{
config.SetOutputUserAttribute(index, perPatch);
}
else
{
config.SetInputUserAttribute(index, (userAttr >> 2) & 3, perPatch);
}
}
if (!isStore &&
((attr >= AttributeConsts.FrontColorDiffuseR && attr < AttributeConsts.ClipDistance0) ||
(attr >= AttributeConsts.TexCoordBase && attr < AttributeConsts.TexCoordEnd)))
{
config.SetUsedFeature(FeatureFlags.FixedFuncAttr);
}
}
}
}
public static bool IsUnconditionalBranch(ref InstOp op)
{
return IsUnconditional(ref op) && op.Props.HasFlag(InstProps.Bra);
}
private static bool IsUnconditional(ref InstOp op)
{
InstConditional condOp = new InstConditional(op.RawOpCode);
if ((op.Name == InstName.Bra || op.Name == InstName.Exit) && condOp.Ccc != Ccc.T)
{
return false;
}
return condOp.Pred == RegisterConsts.PredicateTrueIndex && !condOp.PredInv;
}
private static bool FindBrxTargets(ShaderConfig config, IEnumerable<Block> blocks, Func<ulong, Block> getBlock)
{
bool hasNewTarget = false;
foreach (Block block in blocks)
{
InstOp lastOp = block.GetLastOp();
bool hasNext = block.HasNext();
if (lastOp.Name == InstName.Brx && block.Successors.Count == (hasNext ? 1 : 0))
{
InstBrx opBrx = new InstBrx(lastOp.RawOpCode);
ulong baseOffset = lastOp.GetAbsoluteAddress();
// An indirect branch could go anywhere,
// try to get the possible target offsets from the constant buffer.
(int cbBaseOffset, int cbOffsetsCount) = FindBrxTargetRange(block, opBrx.SrcA);
if (cbOffsetsCount != 0)
{
hasNewTarget = true;
}
for (int i = 0; i < cbOffsetsCount; i++)
{
uint targetOffset = config.ConstantBuffer1Read(cbBaseOffset + i * 4);
Block target = getBlock(baseOffset + targetOffset);
target.Predecessors.Add(block);
block.Successors.Add(target);
}
}
}
return hasNewTarget;
}
private static (int, int) FindBrxTargetRange(Block block, int brxReg)
{
// Try to match the following pattern:
//
// IMNMX.U32 Rx, Rx, UpperBound, PT
// SHL Rx, Rx, 0x2
// LDC Rx, c[0x1][Rx+BaseOffset]
//
// Here, Rx is an arbitrary register, "UpperBound" and "BaseOffset" are constants.
// The above pattern is assumed to be generated by the compiler before BRX,
// as the instruction is usually used to implement jump tables for switch statement optimizations.
// On a successful match, "BaseOffset" is the offset in bytes where the jump offsets are
// located on the constant buffer, and "UpperBound" is the total number of offsets for the BRX, minus 1.
HashSet<Block> visited = new HashSet<Block>();
var ldcLocation = FindFirstRegWrite(visited, new BlockLocation(block, block.OpCodes.Count - 1), brxReg);
if (ldcLocation.Block == null || ldcLocation.Block.OpCodes[ldcLocation.Index].Name != InstName.Ldc)
{
return (0, 0);
}
GetOp<InstLdc>(ldcLocation, out var opLdc);
if (opLdc.CbufSlot != 1 || opLdc.AddressMode != 0)
{
return (0, 0);
}
var shlLocation = FindFirstRegWrite(visited, ldcLocation, opLdc.SrcA);
if (shlLocation.Block == null || !shlLocation.IsImmInst(InstName.Shl))
{
return (0, 0);
}
GetOp<InstShlI>(shlLocation, out var opShl);
if (opShl.Imm20 != 2)
{
return (0, 0);
}
var imnmxLocation = FindFirstRegWrite(visited, shlLocation, opShl.SrcA);
if (imnmxLocation.Block == null || !imnmxLocation.IsImmInst(InstName.Imnmx))
{
return (0, 0);
}
GetOp<InstImnmxI>(imnmxLocation, out var opImnmx);
if (opImnmx.Signed || opImnmx.SrcPred != RegisterConsts.PredicateTrueIndex || opImnmx.SrcPredInv)
{
return (0, 0);
}
return (opLdc.CbufOffset, opImnmx.Imm20 + 1);
}
private static void GetOp<T>(BlockLocation location, out T op) where T : unmanaged
{
ulong rawOp = location.Block.OpCodes[location.Index].RawOpCode;
op = Unsafe.As<ulong, T>(ref rawOp);
}
private struct BlockLocation
{
public Block Block { get; }
public int Index { get; }
public BlockLocation(Block block, int index)
{
Block = block;
Index = index;
}
public bool IsImmInst(InstName name)
{
InstOp op = Block.OpCodes[Index];
return op.Name == name && op.Props.HasFlag(InstProps.Ib);
}
}
private static BlockLocation FindFirstRegWrite(HashSet<Block> visited, BlockLocation location, int regIndex)
{
Queue<BlockLocation> toVisit = new Queue<BlockLocation>();
toVisit.Enqueue(location);
visited.Add(location.Block);
while (toVisit.TryDequeue(out var currentLocation))
{
Block block = currentLocation.Block;
for (int i = currentLocation.Index - 1; i >= 0; i--)
{
if (WritesToRegister(block.OpCodes[i], regIndex))
{
return new BlockLocation(block, i);
}
}
foreach (Block predecessor in block.Predecessors)
{
if (visited.Add(predecessor))
{
toVisit.Enqueue(new BlockLocation(predecessor, predecessor.OpCodes.Count));
}
}
}
return new BlockLocation(null, 0);
}
private static bool WritesToRegister(InstOp op, int regIndex)
{
// Predicate instruction only ever writes to predicate, so we shouldn't check those.
if ((op.Props & (InstProps.Rd | InstProps.Rd2)) == 0)
{
return false;
}
if (op.Props.HasFlag(InstProps.Rd2) && (byte)(op.RawOpCode >> 28) == regIndex)
{
return true;
}
return (byte)op.RawOpCode == regIndex;
}
private enum MergeType
{
Brk,
Cont,
Sync
}
private struct PathBlockState
{
public Block Block { get; }
private enum RestoreType
{
None,
PopPushOp,
PushBranchOp
}
private RestoreType _restoreType;
private ulong _restoreValue;
private MergeType _restoreMergeType;
public bool ReturningFromVisit => _restoreType != RestoreType.None;
public PathBlockState(Block block)
{
Block = block;
_restoreType = RestoreType.None;
_restoreValue = 0;
_restoreMergeType = default;
}
public PathBlockState(int oldStackSize)
{
Block = null;
_restoreType = RestoreType.PopPushOp;
_restoreValue = (ulong)oldStackSize;
_restoreMergeType = default;
}
public PathBlockState(ulong syncAddress, MergeType mergeType)
{
Block = null;
_restoreType = RestoreType.PushBranchOp;
_restoreValue = syncAddress;
_restoreMergeType = mergeType;
}
public void RestoreStackState(Stack<(ulong, MergeType)> branchStack)
{
if (_restoreType == RestoreType.PushBranchOp)
{
branchStack.Push((_restoreValue, _restoreMergeType));
}
else if (_restoreType == RestoreType.PopPushOp)
{
while (branchStack.Count > (uint)_restoreValue)
{
branchStack.Pop();
}
}
}
}
private static void PropagatePushOp(Dictionary<ulong, Block> blocks, Block currBlock, int pushOpIndex)
{
PushOpInfo pushOpInfo = currBlock.PushOpCodes[pushOpIndex];
InstOp pushOp = pushOpInfo.Op;
Block target = blocks[pushOp.GetAbsoluteAddress()];
Stack<PathBlockState> workQueue = new Stack<PathBlockState>();
HashSet<Block> visited = new HashSet<Block>();
Stack<(ulong, MergeType)> branchStack = new Stack<(ulong, MergeType)>();
void Push(PathBlockState pbs)
{
// When block is null, this means we are pushing a restore operation.
// Restore operations are used to undo the work done inside a block
// when we return from it, for example it pops addresses pushed by
// SSY/PBK instructions inside the block, and pushes addresses poped
// by SYNC/BRK.
// For blocks, if it's already visited, we just ignore to avoid going
// around in circles and getting stuck here.
if (pbs.Block == null || !visited.Contains(pbs.Block))
{
workQueue.Push(pbs);
}
}
Push(new PathBlockState(currBlock));
while (workQueue.TryPop(out PathBlockState pbs))
{
if (pbs.ReturningFromVisit)
{
pbs.RestoreStackState(branchStack);
continue;
}
Block current = pbs.Block;
// If the block was already processed, we just ignore it, otherwise
// we would push the same child blocks of an already processed block,
// and go around in circles until memory is exhausted.
if (!visited.Add(current))
{
continue;
}
int pushOpsCount = current.PushOpCodes.Count;
if (pushOpsCount != 0)
{
Push(new PathBlockState(branchStack.Count));
for (int index = pushOpIndex; index < pushOpsCount; index++)
{
InstOp currentPushOp = current.PushOpCodes[index].Op;
MergeType pushMergeType = GetMergeTypeFromPush(currentPushOp.Name);
branchStack.Push((currentPushOp.GetAbsoluteAddress(), pushMergeType));
}
}
pushOpIndex = 0;
bool hasNext = current.HasNext();
if (hasNext)
{
Push(new PathBlockState(current.Successors[0]));
}
InstOp lastOp = current.GetLastOp();
if (IsPopBranch(lastOp.Name))
{
MergeType popMergeType = GetMergeTypeFromPop(lastOp.Name);
bool found = true;
ulong targetAddress = 0UL;
MergeType mergeType;
do
{
if (branchStack.Count == 0)
{
found = false;
break;
}
(targetAddress, mergeType) = branchStack.Pop();
// Push the target address (this will be used to push the address
// back into the PBK/PCNT/SSY stack when we return from that block),
Push(new PathBlockState(targetAddress, mergeType));
}
while (mergeType != popMergeType);
// Make sure we found the correct address,
// the push and pop instruction types must match, so:
// - BRK can only consume addresses pushed by PBK.
// - CONT can only consume addresses pushed by PCNT.
// - SYNC can only consume addresses pushed by SSY.
if (found)
{
if (branchStack.Count == 0)
{
// If the entire stack was consumed, then the current pop instruction
// just consumed the address from our push instruction.
if (current.SyncTargets.TryAdd(pushOp.Address, new SyncTarget(pushOpInfo, current.SyncTargets.Count)))
{
pushOpInfo.Consumers.Add(current, Local());
target.Predecessors.Add(current);
current.Successors.Add(target);
}
}
else
{
// Push the block itself into the work queue for processing.
Push(new PathBlockState(blocks[targetAddress]));
}
}
}
else
{
// By adding them in descending order (sorted by address), we process the blocks
// in order (of ascending address), since we work with a LIFO.
foreach (Block possibleTarget in current.Successors.OrderByDescending(x => x.Address))
{
if (!hasNext || possibleTarget != current.Successors[0])
{
Push(new PathBlockState(possibleTarget));
}
}
}
}
}
public static bool IsPopBranch(InstName name)
{
return name == InstName.Brk || name == InstName.Cont || name == InstName.Sync;
}
private static MergeType GetMergeTypeFromPush(InstName name)
{
return name switch
{
InstName.Pbk => MergeType.Brk,
InstName.Pcnt => MergeType.Cont,
_ => MergeType.Sync
};
}
private static MergeType GetMergeTypeFromPop(InstName name)
{
return name switch
{
InstName.Brk => MergeType.Brk,
InstName.Cont => MergeType.Cont,
_ => MergeType.Sync
};
}
}
}