Changeset 213 for branches/interpreter2/UOptimizer.pas

Timestamp:

Apr 22, 2020, 10:23:31 PM (5 years ago)

Author:

chronos

Message:

• Added: Transformation of Result variable assignment into Return statement.

File:

• branches/interpreter2/UOptimizer.pas (modified) (7 diffs)

branches/interpreter2/UOptimizer.pas

@@ -9 +9 @@
 
 type
+  TOptimizeFeature = (ofReplaceRepeatUntilByWhileDo, ofReplaceResultByReturn);
+  TOptimizeFeatures = set of TOptimizeFeature;
 
   { TOptimizer }
@@ -18 +20 @@
   public
     Prog: TProgram;
+    Features: TOptimizeFeatures;
     procedure Optimize;
   end;
@@ -29 +32 @@
 var
   I: Integer;
+  TempNewNode: TSourceNode;
 begin
   for I := 0 to SourceNodes.Count - 1 do begin
     if SourceNodes[I] is TSourceNode then begin
-      OptimizeNode(TSourceNode(SourceNodes[I]), NewNode);
-      if Assigned(NewNode) and (NewNode <> TSourceNode(SourceNodes[I])) then begin
-        SourceNodes[I] := NewNode;
+      OptimizeNode(TSourceNode(SourceNodes[I]), TempNewNode);
+      if Assigned(TempNewNode) and (TempNewNode <> TSourceNode(SourceNodes[I])) then begin
+        SourceNodes[I] := TempNewNode;
       end;
     end else raise Exception.Create('Unsupported node type');
@@ -46 +50 @@
   WhileDo: TWhileDo;
   Condition: TIfThenElse;
+  Return: TReturn;
   Field: TField;
   Obj: TObject;
+  TempNewNode: TSourceNode;
 begin
   NewNode := nil;
@@ -55 +61 @@
     OptimizeNodes(TSourceNodes(SourceNode), NewNode)
   end else
-  if SourceNode is TRepeatUntil then begin
+  if (ofReplaceRepeatUntilByWhileDo in Features) and (SourceNode is TRepeatUntil) then begin
     WhileDo := TWhileDo.Create;
     WhileDo.Command := TBeginEnd.Create;
@@ -79 +85 @@
     NewNode := WhileDo;
   end else
+  if (ofReplaceResultByReturn in Features) and (SourceNode is TAssignment) then begin
+    if TAssignment(SourceNode).Variable.Name = 'Result' then begin
+      Return := TReturn.Create;
+      Return.Parent := TAssignment(SourceNode).Parent;
+      Return.Expression.Free;
+      Return.Expression := TAssignment(SourceNode).Expression;
+      Return.Expression.Parent := Return;
+      TAssignment(SourceNode).Expression := TExpression.Create;
+      NewNode := Return;
+    end;
+  end else
   if SourceNode is TSourceNode then begin
     for I := 0 to SourceNode.FieldsCount - 1 do begin
@@ -85 +102 @@
         SourceNode.GetValue(I, Obj);
         if Obj is TSourceNode then begin
-          OptimizeNode(TSourceNode(Obj), NewNode);
-          if Assigned(NewNode) and (NewNode <> TSourceNode(Obj)) then begin
-            SourceNode.SetValueObject(I, NewNode);
+          OptimizeNode(TSourceNode(Obj), TempNewNode);
+          if Assigned(TempNewNode) and (TempNewNode <> TSourceNode(Obj)) then begin
+            SourceNode.SetValueObject(I, TempNewNode);
           end;
         end;