public void Transform(Procedure proc)
{
this.ssa = new SsaState(proc, null);
this.asta = new AliasState();
this.currentDef = new Dictionary <Block, Dictionary <Storage, SsaIdentifier> >();
this.incompletePhis = new Dictionary <Block, Dictionary <Storage, SsaIdentifier> >();
this.sealedBlocks = new HashSet <Block>();
foreach (Block b in new DfsIterator <Block>(proc.ControlGraph).PreOrder())
{
this.block = b;
this.currentDef.Add(block, new Dictionary <Storage, SsaIdentifier>()); // new StorageEquality()));
foreach (var s in b.Statements.ToList())
{
this.stm = s;
stm.Instruction = stm.Instruction.Accept(this);
}
}
}
/// <summary>
/// Registers the fact that identifier <paramref name="id"/> is
/// modified in the block <paramref name="b" /> and generates a
/// fresh SSA identifier.
/// </summary>
/// <param name="bs">The block in which the identifier was changed</param>
/// <param name="sid">The identifier after being SSA transformed.</param>
/// <returns>The new SSA identifier</returns>
public override Identifier WriteVariable(SsaBlockState bs, SsaIdentifier sid)
{
DebugEx.Verbose(trace, " WriteBlockLocalVariable: ({0}, {1}, ({2})", bs.Block.Name, id, this.liveBits);
if (!bs.currentDef.TryGetValue(id.Storage.Domain, out var aliasState))
{
aliasState = new AliasState();
bs.currentDef.Add(id.Storage.Domain, aliasState);
}
var stgDef = id.Storage;
var defRange = stgDef.GetBitRange();
for (int i = 0; i < aliasState.Definitions.Count; ++i)
{
var(sidPrev, prevRange, offset) = aliasState.Definitions[i];
var stgPrev = sidPrev.Identifier.Storage;
if (defRange.Covers(prevRange))
{
DebugEx.Verbose(trace, " overwriting: {0}", sidPrev.Identifier);
aliasState.Definitions.RemoveAt(i);
--i;
}
}
aliasState.Definitions.Add((sid, defRange, this.Offset));
DebugEx.Verbose(trace, " writing: {0}", sid.Identifier);
var newDict = aliasState.ExactAliases
.Where(kv => !kv.Key.OverlapsWith(id.Storage))
.ToDictionary(kv => kv.Key, kv => kv.Value);
if (id.Storage == sid.Identifier.Storage)
{
newDict[id.Storage] = sid;
}
aliasState.ExactAliases = newDict;
return(sid.Identifier);
}