/// <summary>
/// Constructs a new phi binding allocator.
/// </summary>
/// <param name="parent">The parent code generator.</param>
/// <param name="cfg">The CFG to use.</param>
public PhiBindingAllocator(CLCodeGenerator parent, CFG cfg)
{
phiMapping = new Dictionary <BasicBlock, List <Variable> >(cfg.Count);
Parent = parent;
CFG = cfg;
Dominators = Dominators.Create(cfg);
}
/// <summary>
/// Creates a new if infos instance.
/// </summary>
/// <param name="dominators">The current dominators.</param>
/// <returns>The created info instance.</returns>
public static IfInfos Create(Dominators dominators)
{
if (dominators == null)
{
throw new ArgumentNullException(nameof(dominators));
}
return(new IfInfos(dominators));
}
/// <summary>
/// Creates a new if infos instance.
/// </summary>
/// <param name="cfg">The current CFG.</param>
/// <returns>The created info instance.</returns>
public static IfInfos Create(CFG cfg)
{
if (cfg == null)
{
throw new ArgumentNullException(nameof(cfg));
}
return(Create(Dominators.Create(cfg)));
}
public override string ToString()
{
var inBlocks = string.Join(", ", InBlocks.Select(x => x.Id));
var outBlocks = string.Join(", ", OutBlocks.Select(x => x.Id));
var idom = IDom == null ? "null" : IDom.Id.ToString();
var doms = string.Join(", ", Dominators.Select(x => x.Id));
var children = string.Join(", ", DominantChildren.Select(x => x.Id));
var df = string.Join(", ", DominanceFrontiers.Select(x => x.Id));
var variables = string.Join(", ", Variables);
return($"Block {Id} ({Name}): nodes={Nodes.Count}, exited={Exited}, in=({inBlocks}), out=({outBlocks}), idom={idom}, doms=({doms}), domchildren=({children}), df=({df}), variables=({variables})");
}
private static bool TryCreate(
Dominators dominators,
CFG.Node exitNode,
out IfInfo ifInfo)
{
Debug.Assert(dominators != null, "Invalid dominators");
Debug.Assert(exitNode != null, "Invalid exit node");
ifInfo = default;
// Check whether this node can be the exit node of an if branch
if (exitNode.NumPredecessors != 2)
{
return(false);
}
// Interpret each predecessor as one branch
var truePred = exitNode.Predecessors[0];
var falsePred = exitNode.Predecessors[1];
// Try to resolve the branch node
var entryNode = dominators.GetImmediateCommonDominator(truePred, falsePred);
if (entryNode.NumSuccessors != 2)
{
return(false);
}
var entryBlock = entryNode.Block;
if (!(entryBlock.Terminator is ConditionalBranch branch))
{
return(false);
}
ifInfo = new IfInfo(
branch.Condition,
entryBlock,
branch.TrueTarget,
branch.FalseTarget,
exitNode.Block);
return(true);
}
/// <summary>
/// Constructs a new info infos instance.
/// </summary>
/// <param name="dominators">The source dominators.</param>
private IfInfos(Dominators dominators)
{
Debug.Assert(dominators != null, "Invalid dominators");
Dominators = dominators;
var cfg = dominators.CFG;
ifs = new Dictionary <CFG.Node, IfInfo>(cfg.Count);
infos = new List <IfInfo>(cfg.Count);
foreach (var exitNode in cfg)
{
// True to resolve if information for the current node
if (TryCreate(dominators, exitNode, out var ifInfo))
{
ifs.Add(exitNode, ifInfo);
infos.Add(ifInfo);
}
}
}
