/// <summary>
/// Compile a set of nodes to ASTs.
///
/// Note:
/// 1. Nodes should be a clique with regarding to convertibility and
/// selection state. That is, these nodes can be safely to be
/// converted into a single code block node. It shouldn't have
/// unconvertible or unselected node on any path (if there is) that
/// connects any two of these nodes, otherwise there will be
/// circular references between unconvertible/unselected node and
/// code block node.
///
/// To split arbitary node set into cliques, use
/// NodeToCodeUtils.GetCliques().
///
/// 2. WorkspaceNodes are all nodes in current workspace. We need the
/// whole graph so that each to-be-converted node will have correct
/// order in the final code block node.
/// </summary>
/// <param name="core">Library core</param>
/// <param name="astBuilder">Ast builder</param>
/// <param name="workspaceNodes">The whole workspace nodes</param>
/// <param name="nodes">Selected node that can be converted to a single code block node</param>
/// <returns></returns>
public static NodeToCodeResult NodeToCode(
ProtoCore.Core core,
AstBuilder astBuilder,
IEnumerable <NodeModel> workspaceNodes,
IEnumerable <NodeModel> nodes)
{
// The basic worflow is:
// 1. Compile each node to get its cde in AST format
//
// 2. Variable numbering to avoid confliction. For example, two
// code block nodes both have assignment "y = x", we need to
// rename "y" to "y1" and "y2" respectively.
//
// 3. Variable remapping. For example, code block node
// "x = 1" connects to "a = b", where the second code block
// node will have initialization "b = x_guid" where "x_guid"
// is because of variable mappining in the first code block
// node. We should restore it to its original name.
//
// Note in step 2 we may rename "x" to "xn".
//
// 4. Generate short name for long name variables. Typically they
// are from output ports from other nodes.
//
// 5. Do constant progation to optimize the generated code.
#region Step 1 AST compilation
var sortedGraph = AstBuilder.TopologicalSortForGraph(workspaceNodes);
var sortedNodes = sortedGraph.Where(nodes.Contains);
var allAstNodes = astBuilder.CompileToAstNodes(sortedNodes, AstBuilder.CompilationContext.NodeToCode, false);
#endregion
#region Step 2 Varialbe numbering
// External inputs will be in input map
// Internal non-cbn will be input map & output map
// Internal cbn will be in renaming map and output map
// Map from mapped variable to its original name. These variables
// are from code block nodes that in the selection.
Dictionary <string, string> renamingMap = null;;
// Input variable to renamed input variable map
Dictionary <string, string> inputMap = null;
// Output variable to renamed output variable map
Dictionary <string, string> outputMap = null;
// Collect all inputs/outputs/candidate renaming variables
GetInputOutputMap(nodes, out inputMap, out outputMap, out renamingMap);
// Variable numbering map. Value field indicates current current
// numbering value of the variable. For example, there are variables
// t1, t2, ... tn and the ID of variable t's NumberingState is n.
var numberingMap = new Dictionary <string, NumberingState>();
// In this step, we'll renumber all variables that going to be in
// the same code block node. That is,
//
// "x = 1; y = x;" and
// "x = 2; y = x;"
//
// Will be renumbered to
//
// "x1 = 1; y1 = x1;" and
// "x2 = 2; y2 = x2;"
var mappedVariables = new HashSet <string>();
foreach (var t in allAstNodes)
{
// Reset variable numbering map
foreach (var p in numberingMap)
{
p.Value.IsNewSession = true;
}
foreach (var astNode in t.Item2)
{
VariableNumbering(core, astNode, t.Item1, numberingMap, renamingMap, inputMap, outputMap, mappedVariables);
}
}
renamingMap = renamingMap.Where(p => !p.Key.Contains("%"))
.ToDictionary(p => p.Key, p => p.Value);
#endregion
#region Step 3 Variable remapping
foreach (var ts in allAstNodes)
{
foreach (var astNode in ts.Item2)
{
VariableRemapping(core, astNode, renamingMap, outputMap, mappedVariables);
}
}
#endregion
#region Step 4 Generate short name
var nameGenerator = new ShortNameGenerator();
// temporary variables are double mapped.
foreach (var key in outputMap.Keys.ToList())
{
if (key.StartsWith(Constants.kTempVarForNonAssignment) &&
outputMap[key].StartsWith(Constants.kTempVarForNonAssignment))
{
string shortName = nameGenerator.GetNextName();
while (mappedVariables.Contains(shortName))
{
shortName = nameGenerator.GetNextName();
}
var tempVar = outputMap[key];
outputMap[key] = shortName;
outputMap[tempVar] = shortName;
mappedVariables.Add(shortName);
}
}
foreach (var ts in allAstNodes)
{
foreach (var astNode in ts.Item2)
{
ShortNameMapping(core, astNode, inputMap, nameGenerator, mappedVariables);
foreach (var kvp in inputMap)
{
if (kvp.Value != String.Empty && outputMap.ContainsKey(kvp.Key))
{
outputMap[kvp.Key] = kvp.Value;
}
}
ShortNameMapping(core, astNode, outputMap, nameGenerator, mappedVariables);
}
}
#endregion
var result = new NodeToCodeResult(allAstNodes.SelectMany(x => x.Item2), inputMap, outputMap);
return(result);
}
/// <summary>
/// Remove temporary assignment from the result. That is, removing
/// assignment "t1 = x" where t1 is a temporary variable. This kind
/// of assginment can be safely removed, but now all nodes that
/// connect to "t1" should re-connect to "x". For example, "a = t1"
/// now should be updated to "a = x".
/// </summary>
/// <param name="result"></param>
/// <returns></returns>
public static NodeToCodeResult ConstantPropagationForTemp(NodeToCodeResult result, IEnumerable <string> outputVariables)
{
var tempVars = new HashSet <string>(
result.OutputMap.Where(p => p.Key.StartsWith(Constants.kTempVarForNonAssignment))
.Select(p => p.Value));
var nonTempAsts = new List <AssociativeNode>();
var tempAssignments = new List <Tuple <IdentifierNode, AssociativeNode> >();
foreach (var ast in result.AstNodes)
{
var expr = ast as BinaryExpressionNode;
if (expr == null || expr.Optr != Operator.assign)
{
nonTempAsts.Add(ast);
continue;
}
var lhs = expr.LeftNode as IdentifierNode;
var rhs = expr.RightNode;
if (lhs == null ||
!tempVars.Contains(lhs.Value) ||
outputVariables.Contains(lhs.Value) ||
!(rhs.IsLiteral || rhs is IdentifierNode))
{
nonTempAsts.Add(ast);
continue;
}
IdentifierFinder finder = new IdentifierFinder(lhs.Value, false);
bool isReferenced = result.AstNodes.Any(n => n.Accept(finder));
bool isRhsDefined = false;
if (rhs is IdentifierNode)
{
var defFinder = new IdentifierFinder((rhs as IdentifierNode).Value, true);
isRhsDefined = result.AstNodes.Any(n => n.Accept(defFinder));
}
if (isReferenced || isRhsDefined)
{
tempAssignments.Add(Tuple.Create(lhs, rhs));
}
else
{
nonTempAsts.Add(ast);
}
}
foreach (var pair in tempAssignments)
{
// Update the map.
var keys = result.OutputMap.Keys.ToList();
for (int i = 0; i < keys.Count; ++i)
{
var value = result.OutputMap[keys[i]];
if (value.Equals(pair.Item1.Value))
{
var rhs = pair.Item2 as IdentifierNode;
if (rhs != null)
{
result.OutputMap[keys[i]] = rhs.Value;
}
}
}
// Update ASTs.
IdentifierReplacer replacer = new IdentifierReplacer(pair.Item1.Value, pair.Item2);
foreach (var ast in nonTempAsts)
{
ast.Accept(replacer);
}
}
return(new NodeToCodeResult(nonTempAsts, result.InputMap, result.OutputMap));
}
