Return back AST optimization of async methods.

teavm-core/src/main/java/org/teavm/javascript/Decompiler.java

@@ -202,7 +202,6 @@ public class Decompiler {
         AsyncMethodNode node = new AsyncMethodNode(method.getReference());
         AsyncProgramSplitter splitter = new AsyncProgramSplitter(asyncMethods);
         splitter.split(method.getProgram());
-        List<Program> partPrograms = new ArrayList<>();
         for (int i = 0; i < splitter.size(); ++i) {
             Integer input = null;
             if (i > 0) {
@@ -214,14 +213,13 @@ public class Decompiler {
             AsyncMethodPart part = getRegularMethodStatement(splitter.getProgram(i), splitter.getBlockSuccessors(i),
                     input);
             node.getBody().add(part);
-            partPrograms.add(splitter.getProgram(i));
         }
         Program program = method.getProgram();
         for (int i = 0; i < program.variableCount(); ++i) {
             node.getVariables().add(program.variableAt(i).getRegister());
         }
         Optimizer optimizer = new Optimizer();
-        optimizer.optimize(node, partPrograms);
+        optimizer.optimize(node, program, splitter);
         node.getModifiers().addAll(mapModifiers(method.getModifiers()));
         int paramCount = Math.min(method.getSignature().length, program.variableCount());
         for (int i = 0; i < paramCount; ++i) {

teavm-core/src/main/java/org/teavm/javascript/Optimizer.java

@@ -15,12 +15,11 @@
  */
 package org.teavm.javascript;
 
-import java.util.List;
 import org.teavm.javascript.ast.AsyncMethodNode;
 import org.teavm.javascript.ast.AsyncMethodPart;
 import org.teavm.javascript.ast.RegularMethodNode;
 import org.teavm.model.Program;
-
+import org.teavm.model.util.AsyncProgramSplitter;
 
 /**
  *
@@ -44,13 +43,17 @@ public class Optimizer {
         }
     }
 
-    public void optimize(AsyncMethodNode method, List<Program> programs) {
+    public void optimize(AsyncMethodNode method, Program program, AsyncProgramSplitter splitter) {
         ReadWriteStatsBuilder stats = new ReadWriteStatsBuilder(method.getVariables().size());
-        for (Program program : programs) {
         stats.analyze(program);
+        for (int i = 0; i < splitter.size(); ++i) {
+            Integer var = splitter.getInput(i);
+            if (var != null) {
+                stats.reads[var]++;
+            }
         }
-        OptimizingVisitor optimizer = new OptimizingVisitor(stats);
         for (AsyncMethodPart part : method.getBody()) {
+            OptimizingVisitor optimizer = new OptimizingVisitor(stats.copy());
             part.getStatement().acceptVisitor(optimizer);
             part.setStatement(optimizer.resultStmt);
         }

teavm-core/src/main/java/org/teavm/javascript/ReadWriteStatsBuilder.java

@@ -15,6 +15,7 @@
  */
 package org.teavm.javascript;
 
+import java.util.Arrays;
 import org.teavm.model.*;
 import org.teavm.model.util.DefinitionExtractor;
 import org.teavm.model.util.UsageExtractor;
@@ -27,11 +28,21 @@ class ReadWriteStatsBuilder {
     public int[] reads;
     public int[] writes;
 
+    private ReadWriteStatsBuilder() {
+    }
+
     public ReadWriteStatsBuilder(int variableCount) {
         reads = new int[variableCount];
         writes = new int[variableCount];
     }
 
+    public ReadWriteStatsBuilder copy() {
+        ReadWriteStatsBuilder result = new ReadWriteStatsBuilder();
+        result.reads = Arrays.copyOf(reads, reads.length);
+        result.writes = Arrays.copyOf(writes, writes.length);
+        return result;
+    }
+
     public void analyze(Program program) {
         DefinitionExtractor defExtractor = new DefinitionExtractor();
         UsageExtractor useExtractor = new UsageExtractor();

teavm-core/src/main/java/org/teavm/javascript/Renderer.java

@@ -533,7 +533,11 @@ public class Renderer implements ExprVisitor, StatementVisitor, RenderingContext
         }
         writer.append(")").ws().append("{").softNewLine().indent();
         method.acceptVisitor(new MethodBodyRenderer());
-        writer.outdent().append("}").newLine();
+        writer.outdent().append("}");
+        if (inner) {
+            writer.append(';');
+        }
+        writer.newLine();
         debugEmitter.emitMethod(null);
     }
 
@@ -630,18 +634,15 @@ public class Renderer implements ExprVisitor, StatementVisitor, RenderingContext
                     writer.append(";").softNewLine();
                 }
                 for (int i = 0; i < methodNode.getBody().size(); ++i) {
-                    writer.append("function $part_").append(i).append("(");
+                    writer.append("var $part_").append(i).ws().append("=").ws().append("$rt_guardAsync(function(");
                     if (i > 0) {
                         writer.append("$restore");
                     }
-                    writer.append(")").ws().append('{').indent().softNewLine();
+                    writer.append(")").ws().append("{").indent().softNewLine();
-                    writer.append("try {").indent().softNewLine();
                     AsyncMethodPart part = methodNode.getBody().get(i);
                     part.getStatement().acceptVisitor(Renderer.this);
-                    writer.outdent().append("} catch ($guard) {").indent().softNewLine();
                     writer.append("return $return($rt_asyncError($guard));").softNewLine();
-                    writer.outdent().append("}").softNewLine();
+                    writer.outdent().append("},").ws().append("$return);").softNewLine();
-                    writer.outdent().append("}").softNewLine();
                 }
                 writer.append("return $part_0();").softNewLine();
             } catch (IOException e) {

teavm-core/src/main/resources/org/teavm/javascript/runtime.js

@@ -455,6 +455,15 @@ function $rt_continue(f) {
        return f;
    }
 }
+function $rt_guardAsync(f, continuation) {
+    return function() {
+        try {
+            return f.apply(this, arguments);
+        } catch (e) {
+            return continuation($rt_asyncError(e));
+        }
+    }
+}
 
 function $dbg_repr(obj) {
     return obj.toString ? obj.toString() : "";

teavm-samples/teavm-samples-async/src/main/java/org/teavm/samples/async/AsyncProgram.java

@@ -55,18 +55,5 @@ public final class AsyncProgram {
             }
         }
         System.out.println("Complete async");
-
-        System.out.println("Throwing exception");
-        try {
-            throwException();
-        } catch (IllegalStateException e) {
-            System.out.println("Exception caught");
-        }
-    }
-
-    private static void throwException() {
-        Thread.yield();
-        System.out.println("Thread.yield called");
-        throw new IllegalStateException();
     }
 }