ryujinx/ARMeilleure/Translation/SsaConstruction.cs
FICTURE7 c805542b29
Allow LocalVariable to be assigned more than once (#2288)
* Allow `LocalVariable` to be assigned more than once

This allows us to write flow controls like loops and if-elses with
LocalVariables participating in phi nodes.

* Add `GetLocalNumber` to operand
2021-05-17 01:54:53 +02:00

289 lines
8.9 KiB
C#

using ARMeilleure.Common;
using ARMeilleure.IntermediateRepresentation;
using ARMeilleure.State;
using System;
using System.Collections.Generic;
using System.Diagnostics;
using static ARMeilleure.IntermediateRepresentation.OperandHelper;
namespace ARMeilleure.Translation
{
static partial class Ssa
{
private class DefMap
{
private readonly Dictionary<int, Operand> _map;
private readonly BitMap _phiMasks;
public DefMap()
{
_map = new Dictionary<int, Operand>();
_phiMasks = new BitMap(RegisterConsts.TotalCount);
}
public bool TryAddOperand(int key, Operand operand)
{
return _map.TryAdd(key, operand);
}
public bool TryGetOperand(int key, out Operand operand)
{
return _map.TryGetValue(key, out operand);
}
public bool AddPhi(int key)
{
return _phiMasks.Set(key);
}
public bool HasPhi(int key)
{
return _phiMasks.IsSet(key);
}
}
public static void Construct(ControlFlowGraph cfg)
{
var globalDefs = new DefMap[cfg.Blocks.Count];
var localDefs = new Operand[cfg.LocalsCount + RegisterConsts.TotalCount];
var dfPhiBlocks = new Queue<BasicBlock>();
for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
{
globalDefs[block.Index] = new DefMap();
}
// First pass, get all defs and locals uses.
for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
{
for (Node node = block.Operations.First; node != null; node = node.ListNext)
{
if (node is not Operation operation)
{
continue;
}
for (int index = 0; index < operation.SourcesCount; index++)
{
Operand src = operation.GetSource(index);
if (TryGetId(src, out int srcKey))
{
Operand local = localDefs[srcKey] ?? src;
operation.SetSource(index, local);
}
}
Operand dest = operation.Destination;
if (TryGetId(dest, out int destKey))
{
Operand local = Local(dest.Type);
localDefs[destKey] = local;
operation.Destination = local;
}
}
for (int key = 0; key < localDefs.Length; key++)
{
Operand local = localDefs[key];
if (local is null)
{
continue;
}
globalDefs[block.Index].TryAddOperand(key, local);
dfPhiBlocks.Enqueue(block);
while (dfPhiBlocks.TryDequeue(out BasicBlock dfPhiBlock))
{
foreach (BasicBlock domFrontier in dfPhiBlock.DominanceFrontiers)
{
if (globalDefs[domFrontier.Index].AddPhi(key))
{
dfPhiBlocks.Enqueue(domFrontier);
}
}
}
}
Array.Clear(localDefs, 0, localDefs.Length);
}
// Second pass, rename variables with definitions on different blocks.
for (BasicBlock block = cfg.Blocks.First; block != null; block = block.ListNext)
{
for (Node node = block.Operations.First; node != null; node = node.ListNext)
{
if (node is not Operation operation)
{
continue;
}
for (int index = 0; index < operation.SourcesCount; index++)
{
Operand src = operation.GetSource(index);
if (TryGetId(src, out int key))
{
Operand local = localDefs[key];
if (local is null)
{
local = FindDef(globalDefs, block, src);
localDefs[key] = local;
}
operation.SetSource(index, local);
}
}
}
Array.Clear(localDefs, 0, localDefs.Length);
}
}
private static Operand FindDef(DefMap[] globalDefs, BasicBlock current, Operand operand)
{
if (globalDefs[current.Index].HasPhi(GetId(operand)))
{
return InsertPhi(globalDefs, current, operand);
}
if (current != current.ImmediateDominator)
{
return FindDefOnPred(globalDefs, current.ImmediateDominator, operand);
}
return Undef();
}
private static Operand FindDefOnPred(DefMap[] globalDefs, BasicBlock current, Operand operand)
{
BasicBlock previous;
do
{
DefMap defMap = globalDefs[current.Index];
int key = GetId(operand);
if (defMap.TryGetOperand(key, out Operand lastDef))
{
return lastDef;
}
if (defMap.HasPhi(key))
{
return InsertPhi(globalDefs, current, operand);
}
previous = current;
current = current.ImmediateDominator;
}
while (previous != current);
return Undef();
}
private static Operand InsertPhi(DefMap[] globalDefs, BasicBlock block, Operand operand)
{
// This block has a Phi that has not been materialized yet, but that
// would define a new version of the variable we're looking for. We need
// to materialize the Phi, add all the block/operand pairs into the Phi, and
// then use the definition from that Phi.
Operand local = Local(operand.Type);
PhiNode phi = new PhiNode(local, block.Predecessors.Count);
AddPhi(block, phi);
globalDefs[block.Index].TryAddOperand(GetId(operand), local);
for (int index = 0; index < block.Predecessors.Count; index++)
{
BasicBlock predecessor = block.Predecessors[index];
phi.SetBlock(index, predecessor);
phi.SetSource(index, FindDefOnPred(globalDefs, predecessor, operand));
}
return local;
}
private static void AddPhi(BasicBlock block, PhiNode phi)
{
Node node = block.Operations.First;
if (node != null)
{
while (node.ListNext is PhiNode)
{
node = node.ListNext;
}
}
if (node is PhiNode)
{
block.Operations.AddAfter(node, phi);
}
else
{
block.Operations.AddFirst(phi);
}
}
private static bool TryGetId(Operand operand, out int result)
{
if (operand is { Kind: OperandKind.Register })
{
Register reg = operand.GetRegister();
if (reg.Type == RegisterType.Integer)
{
result = reg.Index;
}
else if (reg.Type == RegisterType.Vector)
{
result = RegisterConsts.IntRegsCount + reg.Index;
}
else if (reg.Type == RegisterType.Flag)
{
result = RegisterConsts.IntAndVecRegsCount + reg.Index;
}
else /* if (reg.Type == RegisterType.FpFlag) */
{
result = RegisterConsts.FpFlagsOffset + reg.Index;
}
return true;
}
else if (operand is { Kind: OperandKind.LocalVariable } && operand.GetLocalNumber() > 0)
{
result = RegisterConsts.TotalCount + operand.GetLocalNumber() - 1;
return true;
}
result = -1;
return false;
}
private static int GetId(Operand operand)
{
if (!TryGetId(operand, out int key))
{
Debug.Fail("OperandKind must be Register or a numbered LocalVariable.");
}
return key;
}
}
}