JS templates

sdk/lib/_internal/compiler/implementation/native_handler.dart

Index: sdk/lib/_internal/compiler/implementation/native_handler.dart
diff --git a/sdk/lib/_internal/compiler/implementation/native_handler.dart b/sdk/lib/_internal/compiler/implementation/native_handler.dart
index f5caa613ec9f0cf6c12aaece4f46a86a157e437e..df70f15d759081556947256524101b983963d5bd 100644
--- a/sdk/lib/_internal/compiler/implementation/native_handler.dart
+++ b/sdk/lib/_internal/compiler/implementation/native_handler.dart
@@ -767,9 +767,9 @@ class NativeBehavior {
   /// [DartType]s or [SpecialType]s instantiated by the native element.
   final List typesInstantiated = [];
 
-  // If this behavior is for a JS expression, [codeAst] contains the
+  // If this behavior is for a JS expression, [codeTemplate] contains the
   // parsed tree.
-  js.Expression codeAst;
+  js.Template codeTemplate;
 
   final SideEffects sideEffects = new SideEffects.empty();
 
@@ -800,8 +800,8 @@ class NativeBehavior {
     }
 
     var behavior = new NativeBehavior();
-    behavior.codeAst = js.js.parseForeignJS(code.dartString.slowToString());
-    new SideEffectsVisitor(behavior.sideEffects).visit(behavior.codeAst);
+    behavior.codeTemplate = js.js.parseForeignJS(code.dartString.slowToString());
+    new SideEffectsVisitor(behavior.sideEffects).visit(behavior.codeTemplate.ast);
 
     String specString = specLiteral.dartString.slowToString();
     // Various things that are not in fact types.
@@ -1162,8 +1162,14 @@ void handleSsaNative(SsaBuilder builder, Expression nativeBody) {
                                      'Unexpected kind: "${element.kind}".');
     }
 
-    builder.push(new HForeign(js.js(nativeMethodCall), backend.dynamicType,
-                              inputs, effects: new SideEffects()));
+    builder.push(
+        new HForeign(
+            // TODO(sra): This could be cached.  The number of templates should
+            // be proportional to the number of native methods, which is bounded
+            // by the dart: libraries.
+            js.js.uncachedExpressionTemplate(nativeMethodCall),
+            backend.dynamicType,
+            inputs, effects: new SideEffects()));
     builder.close(new HReturn(builder.pop())).addSuccessor(builder.graph.exit);
   } else {
     if (parameters.parameterCount != 0) {
@@ -1173,7 +1179,8 @@ void handleSsaNative(SsaBuilder builder, Expression nativeBody) {
     }
     LiteralString jsCode = nativeBody.asLiteralString();
     builder.push(new HForeign.statement(
-        new js.LiteralStatement(jsCode.dartString.slowToString()),
+        js.js.expressionTemplateYielding(
+            new js.LiteralStatement(jsCode.dartString.slowToString())),
         <HInstruction>[],
         new SideEffects(),
         null,