Build new IR for functions returning a constant

sdk/lib/_internal/compiler/implementation/inferrer/ir_type_inferrer.dart

Index: sdk/lib/_internal/compiler/implementation/inferrer/ir_type_inferrer.dart
diff --git a/sdk/lib/_internal/compiler/implementation/inferrer/ir_type_inferrer.dart b/sdk/lib/_internal/compiler/implementation/inferrer/ir_type_inferrer.dart
new file mode 100644
index 0000000000000000000000000000000000000000..c0d0262c09d10592485b860a89226a4523ea5939
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+++ b/sdk/lib/_internal/compiler/implementation/inferrer/ir_type_inferrer.dart
@@ -0,0 +1,84 @@
+// 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 ir_type_inferrer;
+
+import '../ir/ir_nodes.dart';
+import 'inferrer_visitor.dart' show
+    TypeSystem;
+import 'simple_types_inferrer.dart' show
+    InferrerEngine;
+import '../elements/elements.dart' show
+    Element, FunctionElement, FunctionSignature;
+import '../dart2jslib.dart' show
+    Compiler, Constant, ConstantSystem;
+
+class IrTypeInferrerVisitor<T> extends IrNodesVisitor<T> {
+  final Compiler compiler;
+  final Element analyzedElement;
+  final TypeSystem<T> types;
+  final InferrerEngine<T, TypeSystem<T>> inferrer;
+
+  IrTypeInferrerVisitor(this.compiler, this.analyzedElement,
+                        InferrerEngine<T, TypeSystem<T>> inferrer)
+    : inferrer = inferrer,
+      types = inferrer.types;
+
+  final Map<IrNode, T> analyzed = new Map<IrNode, T>();
+
+  T recordAnalyzed(IrNode node, T type) => analyzed[node] = type;
+
+  T run() {
+    if (analyzedElement.isField()) {
+      // TODO(lry): handle fields.
+      throw "Type infer from IR for field $analyzedElement";
+    }
+    FunctionElement function = analyzedElement;
+    FunctionSignature signature = function.computeSignature(compiler);
+    IrFunction node = compiler.irBuilder.getIr(function);
+    // TODO(lry): handle parameters.
+
+    if (function.isNative()) {
+      // TODO(lry): handle native.
+      throw "Type infer from IR for native $analyzedElement";
+    }
+
+    if (analyzedElement.isGenerativeConstructor()) {
+      // TODO(lry): handle constructors.
+      throw "Type infer from IR for constructor $analyzedElement";
+    }
+
+    if (analyzedElement.isSynthesized) {
+      // TODO(lry): handle synthethics.
+      throw "Type infer from IR for synthetic $analyzedElement";
+    }
+
+    visitAll(node.statements);
+  }
+
+  T typeOfConstant(Constant constant) {
+    if (constant.isBool()) return types.boolType;
+    if (constant.isNum()) {
+      ConstantSystem constantSystem = compiler.backend.constantSystem;
+      // The JavaScript backend may turn this literal into a double at runtime.
+      if (constantSystem.isDouble(constant)) return types.doubleType;
+      return types.intType;
+    }
+    if (constant.isString()) return types.stringType;
+    if (constant.isNull()) return types.nullType;
+    compiler.internalError("Unexpected constant: $constant");
+  }
+
+  T visitIrConstant(IrConstant node) {
+    return recordAnalyzed(node, typeOfConstant(node.value));
+  }
+
+  T visitIrReturn(IrReturn node) {
+    inferrer.addReturnTypeFor(analyzedElement, null, analyzed[node.value]);
+  }
+
+  T visitNode(IrNode node) {
+    compiler.internalError('Unexpected IrNode $node');
+  }
+}