Lower map literals to constructor or function calls in builder

pkg/compiler/lib/src/cps_ir/cps_ir_builder_task.dart

 // Copyright (c) 2013, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library dart2js.ir_builder_task;
 
 import '../closure.dart' as closure;
 import '../common.dart';
 import '../common/names.dart' show
     Names,
@@ skipping 1316 matching lines @@
     InterfaceType type = elements.getType(node);
     return irBuilder.buildListLiteral(type, values,
         allocationSiteType: getAllocationSiteType(node));
   }
 
   ir.Primitive visitLiteralMap(ast.LiteralMap node) {
     assert(irBuilder.isOpen);
     if (node.isConst) {
       return translateConstant(node);
     }
+
     InterfaceType type = elements.getType(node);
-    List<ir.LiteralMapEntry> entries =
-        node.entries.nodes.mapToList((ast.LiteralMapEntry e) {
-          return new ir.LiteralMapEntry(visit(e.key), visit(e.value));
-        });
-    return irBuilder.addPrimitive(new ir.LiteralMap(type, entries));
+
+    if (node.entries.nodes.isEmpty) {
+      if (type.treatAsRaw) {
+        return irBuilder.buildStaticFunctionInvocation(
+            helpers.mapLiteralUntypedEmptyMaker,
+            <ir.Primitive>[],
+            sourceInformation: sourceInformationBuilder.buildNew(node));
+      } else {
+        ConstructorElement constructor = helpers.mapLiteralConstructorEmpty;
+        return irBuilder.buildConstructorInvocation(
+            constructor.effectiveTarget,
+            CallStructure.NO_ARGS,
+            constructor.computeEffectiveTargetType(type),
+            <ir.Primitive>[],
+            sourceInformationBuilder.buildNew(node));
+      }
+    }
+
+    List<ir.Primitive> keysAndValues = <ir.Primitive>[];
+    for (ast.LiteralMapEntry entry in node.entries.nodes.toList()) {
+      keysAndValues.add(visit(entry.key));
+      keysAndValues.add(visit(entry.value));
+    }
+    ir.Primitive keysAndValuesList =
+        irBuilder.buildListLiteral(null, keysAndValues);
+
+    if (type.treatAsRaw) {
+      return irBuilder.buildStaticFunctionInvocation(
+          helpers.mapLiteralUntypedMaker,
+          <ir.Primitive>[keysAndValuesList],
+          sourceInformation: sourceInformationBuilder.buildNew(node));
+    } else {
+      ConstructorElement constructor = helpers.mapLiteralConstructor;
+      return irBuilder.buildConstructorInvocation(
+          constructor.effectiveTarget,
+          CallStructure.ONE_ARG,
+          constructor.computeEffectiveTargetType(type),
+          <ir.Primitive>[keysAndValuesList],
+          sourceInformationBuilder.buildNew(node));
+    }
   }
 
   ir.Primitive visitLiteralSymbol(ast.LiteralSymbol node) {
     assert(irBuilder.isOpen);
     return translateConstant(node);
   }
 
   ir.Primitive visitParenthesizedExpression(
       ast.ParenthesizedExpression node) {
     assert(irBuilder.isOpen);
@@ skipping 2200 matching lines @@
   }
 
   Element get closureConverter {
     return _backend.helpers.closureConverter;
   }
 
   void addNativeMethod(FunctionElement function) {
     _backend.emitter.nativeEmitter.nativeMethods.add(function);
   }
 }