[K/JS] Compile Kotlin coroutines as JS generator ^KT-63038 Fixed

js/js.ast/src/org/jetbrains/kotlin/js/backend/JsPrecedenceVisitor.java

@@ -80,6 +80,11 @@ class JsPrecedenceVisitor extends JsVisitor {
         answer = 16;
     }
 
+    @Override
+    public void visitYield(@NotNull JsYield yield) {
+        answer = 2; // https://esdiscuss.org/topic/precedence-of-yield-operator
+    }
+
     @Override
     public void visitNameRef(@NotNull JsNameRef nameRef) {
         if (nameRef.isLeaf()) {

js/js.ast/src/org/jetbrains/kotlin/js/backend/JsToStringGenerationVisitor.java

@@ -27,6 +27,7 @@ public class JsToStringGenerationVisitor extends JsVisitor {
     private static final char[] CHARS_CLASS = "class".toCharArray();
     private static final char[] CHARS_CONSTRUCTOR = "constructor".toCharArray();
     private static final char[] CHARS_CONTINUE = "continue".toCharArray();
+    private static final char[] CHARS_YIELD = "yield".toCharArray();
     private static final char[] CHARS_DEBUGGER = "debugger".toCharArray();
     private static final char[] CHARS_DEFAULT = "default".toCharArray();
     private static final char[] CHARS_DO = "do".toCharArray();
@@ -46,6 +47,7 @@ public class JsToStringGenerationVisitor extends JsVisitor {
     private static final char[] CHARS_RETURN = "return".toCharArray();
     private static final char[] CHARS_SWITCH = "switch".toCharArray();
     private static final char[] CHARS_THIS = "this".toCharArray();
+    private static final char CHARS_GENERATOR = '*';
 
     private static final char[] CHARS_SUPER = "super".toCharArray();
     private static final char[] CHARS_THROW = "throw".toCharArray();
@@ -337,6 +339,24 @@ public class JsToStringGenerationVisitor extends JsVisitor {
         popSourceInfo();
     }
 
+    @Override
+    public void visitYield(@NotNull JsYield x) {
+        pushSourceInfo(x.getSource());
+        printCommentsBeforeNode(x);
+
+        p.print(CHARS_YIELD);
+
+        JsExpression expression = x.getExpression();
+
+        if (expression != null) {
+            space();
+            accept(x.getExpression());
+        }
+
+        printCommentsAfterNode(x);
+        popSourceInfo();
+    }
+
     private void continueOrBreakLabel(JsContinue x) {
         JsNameRef label = x.getLabel();
         if (label != null) {
@@ -684,6 +704,10 @@ public class JsToStringGenerationVisitor extends JsVisitor {
             space();
         }
 
+        if (x.isGenerator()) {
+            p.print(CHARS_GENERATOR);
+        }
+
         if (x.getName() != null) {
             nameOf(x);
         }

js/js.ast/src/org/jetbrains/kotlin/js/backend/ast/JsFunction.java

@@ -13,7 +13,7 @@ import org.jetbrains.annotations.Nullable;
 import java.util.*;
 
 public final class JsFunction extends JsLiteral implements HasName {
-    public enum Modifier { STATIC, GET, SET }
+    public enum Modifier { STATIC, GET, SET, GENERATOR }
 
     @NotNull
     private JsBlock body;
@@ -81,6 +81,10 @@ public final class JsFunction extends JsLiteral implements HasName {
         return modifiers != null && modifiers.contains(Modifier.SET);
     }
 
+    public boolean isGenerator() {
+        return modifiers != null && modifiers.contains(Modifier.GENERATOR);
+    }
+
     @NotNull
     public Set<Modifier> getModifiers() {
         if (modifiers == null) {

js/js.ast/src/org/jetbrains/kotlin/js/backend/ast/JsNew.java

@@ -22,6 +22,10 @@ public final class JsNew extends JsExpression.JsExpressionHasArguments {
         this.constructorExpression = constructorExpression;
     }
 
+    public JsNew(JsExpression constructorExpression, JsExpression... arguments) {
+        this(constructorExpression, new SmartList<JsExpression>(arguments));
+    }
+
     public JsExpression getConstructorExpression() {
         return constructorExpression;
     }

js/js.ast/src/org/jetbrains/kotlin/js/backend/ast/JsVisitor.kt

@@ -60,6 +60,9 @@ abstract class JsVisitor {
     open fun visitContinue(x: JsContinue): Unit =
             visitElement(x)
 
+    open fun visitYield(x: JsYield): Unit =
+        visitElement(x)
+
     open fun visitDebugger(x: JsDebugger): Unit =
             visitElement(x)
 

js/js.ast/src/org/jetbrains/kotlin/js/backend/ast/JsVisitorWithContext.java

@@ -101,6 +101,9 @@ public abstract class JsVisitorWithContext {
     public void endVisit(@NotNull JsContinue x, @NotNull JsContext ctx) {
     }
 
+    public void endVisit(@NotNull JsYield x, @NotNull JsContext ctx) {
+    }
+
     public void endVisit(@NotNull JsDebugger x, @NotNull JsContext ctx) {
     }
 
@@ -274,6 +277,10 @@ public abstract class JsVisitorWithContext {
         return true;
     }
 
+    public boolean visit(@NotNull JsYield x, @NotNull JsContext ctx) {
+        return true;
+    }
+
     public boolean visit(@NotNull JsDebugger x, @NotNull JsContext ctx) {
         return true;
     }

js/js.ast/src/org/jetbrains/kotlin/js/backend/ast/JsYield.kt

@@ -0,0 +1,29 @@
+/*
+ * Copyright 2010-2023 JetBrains s.r.o. and Kotlin Programming Language contributors.
+ * Use of this source code is governed by the Apache 2.0 license that can be found in the license/LICENSE.txt file.
+ */
+
+package org.jetbrains.kotlin.js.backend.ast
+
+import org.jetbrains.kotlin.js.util.AstUtil
+
+class JsYield(var expression: JsExpression?) : JsExpression() {
+    override fun accept(visitor: JsVisitor) {
+        visitor.visitYield(this)
+    }
+
+    override fun acceptChildren(visitor: JsVisitor) {
+        visitor.accept(expression)
+    }
+
+    override fun deepCopy(): JsExpression {
+        return JsYield(AstUtil.deepCopy(expression)).withMetadataFrom(this)
+    }
+
+    override fun traverse(visitor: JsVisitorWithContext, ctx: JsContext<*>) {
+        if (visitor.visit(this, ctx)) {
+            expression = visitor.accept(expression)
+        }
+        visitor.endVisit(this, ctx)
+    }
+}

js/js.ast/src/org/jetbrains/kotlin/js/backend/ast/metadata/metadataProperties.kt

@@ -82,6 +82,8 @@ var HasMetadata.synthetic: Boolean by MetadataProperty(default = false)
 var HasMetadata.isInlineClassBoxing: Boolean by MetadataProperty(default = false)
 var HasMetadata.isInlineClassUnboxing: Boolean by MetadataProperty(default = false)
 
+var HasMetadata.isGeneratorFunction: Boolean by MetadataProperty(default = false)
+
 var HasMetadata.sideEffects: SideEffectKind by MetadataProperty(default = SideEffectKind.AFFECTS_STATE)
 
 /**