Добавлен оптимизация: объединение инструкций

Author: aNNiMON

src/com/annimon/ownlang/parser/Optimizer.java

@@ -7,6 +7,7 @@
 import com.annimon.ownlang.parser.optimization.ConstantPropagation;
 import com.annimon.ownlang.parser.optimization.DeadCodeElimination;
 import com.annimon.ownlang.parser.optimization.ExpressionSimplification;
+import com.annimon.ownlang.parser.optimization.InstructionCombining;
 import com.annimon.ownlang.parser.optimization.Optimizable;
 import com.annimon.ownlang.parser.optimization.SummaryOptimization;
 
@@ -19,11 +20,12 @@ public static Statement optimize(Statement statement, int level) {
             new ConstantFolding(),
             new ConstantPropagation(),
             new DeadCodeElimination(),
-            new ExpressionSimplification()
+            new ExpressionSimplification(),
+            new InstructionCombining()
         });
 
         Node result = statement;
-        if (true || level >= 9) {
+        if (level >= 9) {
             int iteration = 0, lastModifications = 0;
             do {
                 lastModifications = optimization.optimizationsCount();

src/com/annimon/ownlang/parser/optimization/InstructionCombining.java

@@ -0,0 +1,110 @@
+package com.annimon.ownlang.parser.optimization;
+
+import com.annimon.ownlang.parser.ast.BlockStatement;
+import com.annimon.ownlang.parser.ast.Expression;
+import com.annimon.ownlang.parser.ast.Node;
+import com.annimon.ownlang.parser.ast.PrintStatement;
+import com.annimon.ownlang.parser.ast.PrintlnStatement;
+import com.annimon.ownlang.parser.ast.Statement;
+import com.annimon.ownlang.parser.ast.ValueExpression;
+import static com.annimon.ownlang.parser.visitors.VisitorUtils.isConstantValue;
+
+/**
+ * Performs instruction combining.
+ */
+public class InstructionCombining extends OptimizationVisitor<Void> implements Optimizable {
+
+    private int printCombinedCount;
+
+    @Override
+    public Node optimize(Node node) {
+        return node.accept(this, null);
+    }
+
+    @Override
+    public int optimizationsCount() {
+        return printCombinedCount;
+    }
+
+    @Override
+    public String summaryInfo() {
+        if (optimizationsCount() == 0) return "";
+        final StringBuilder sb = new StringBuilder();
+        if (printCombinedCount > 0) {
+            sb.append("\nPrint statement combined: ").append(printCombinedCount);
+        }
+        return sb.toString();
+    }
+
+    @Override
+    public Node visit(BlockStatement s, Void t) {
+        final int size = s.statements.size();
+        if (size <= 1) {
+            return super.visit(s, t);
+        }
+
+        boolean changed = false;
+        final BlockStatement result = new BlockStatement();
+        int i;
+        for (i = 1; i < size; i++) {
+            Statement s1 = s.statements.get(i - 1);
+            Statement s2 = s.statements.get(i);
+            Node n1 = s1.accept(this, t);
+            Node n2 = s2.accept(this, t);
+            if (n1 != s1 || n2 != s2) {
+                changed = true;
+            }
+            final Node combined = tryCombine(n1, n2);
+            if (combined == null) {
+                result.add((Statement) n1);
+            } else {
+                changed = true;
+                result.add(consumeStatement(combined));
+                i++;
+            }
+        }
+        if (i == size) {
+            // Last node
+            Statement s2 = s.statements.get(size - 1);
+            Node n2 = s2.accept(this, t);
+            if (n2 != s2) {
+                changed = true;
+            }
+            result.add((Statement) n2);
+        }
+        if (changed) {
+            return result;
+        }
+        return super.visit(s, t);
+    }
+
+    private Node tryCombine(Node n1, Node n2) {
+        final int n1Type;
+        if (n1 instanceof PrintStatement) n1Type = 1;
+        else if (n1 instanceof PrintlnStatement) n1Type = 2;
+        else n1Type = 0;
+
+        final int n2Type;
+        if (n2 instanceof PrintStatement) n2Type = 1;
+        else if (n2 instanceof PrintlnStatement) n2Type = 2;
+        else n2Type = 0;
+
+        if (n1Type != 0 && n2Type != 0) {
+            final Expression e1 = (n1Type == 1)
+                    ? ((PrintStatement) n1).expression
+                    : ((PrintlnStatement) n1).expression;
+            final Expression e2 = (n2Type == 1)
+                    ? ((PrintStatement) n2).expression
+                    : ((PrintlnStatement) n2).expression;
+            if (isConstantValue(e1) && isConstantValue(e2)) {
+                String s1 = e1.eval().asString();
+                if (n1Type == 2) s1 += System.lineSeparator();
+                String s2 = e2.eval().asString();
+                if (n2Type == 2) s2 += System.lineSeparator();
+                printCombinedCount++;
+                return new PrintStatement(new ValueExpression(s1 + s2));
+            }
+        }
+        return null;
+    }
+}

src/com/annimon/ownlang/parser/visitors/VisitorUtils.java

@@ -56,6 +56,13 @@ public static boolean isValueAsInt(Node node, int valueToCheck) {
         return value.asInt() == valueToCheck;
     }
 
+    public static boolean isConstantValue(Node node) {
+        if (!isValue(node)) return false;
+
+        final int type = ((ValueExpression) node).value.type();
+        return ( (type == Types.NUMBER) || (type == Types.STRING) );
+    }
+
     public static boolean isSameVariables(Node n1, Node n2) {
         if (isVariable(n1) && isVariable(n2)) {
             final VariableExpression v1 = (VariableExpression) n1;