Move dart2js from sdk/lib/_internal/compiler to pkg/compiler

sdk/lib/_internal/compiler/implementation/ssa/builder.dart

Index: sdk/lib/_internal/compiler/implementation/ssa/builder.dart
diff --git a/sdk/lib/_internal/compiler/implementation/ssa/builder.dart b/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
deleted file mode 100644
index abd5e29594869b5486b149f52854b583ddcb859b..0000000000000000000000000000000000000000
--- a/sdk/lib/_internal/compiler/implementation/ssa/builder.dart
+++ /dev/null
@@ -1,6578 +0,0 @@
-// Copyright (c) 2012, 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.
-
-part of ssa;
-
-/// A synthetic local variable only used with the SSA graph.
-///
-/// For instance used for holding return value of function or the exception of a
-/// try-catch statement.
-class SyntheticLocal extends Local {
-  final String name;
-  final ExecutableElement executableContext;
-
-  SyntheticLocal(this.name, this.executableContext);
-}
-
-class SsaBuilderTask extends CompilerTask {
-  final CodeEmitterTask emitter;
-  final JavaScriptBackend backend;
-
-  String get name => 'SSA builder';
-
-  SsaBuilderTask(JavaScriptBackend backend)
-    : emitter = backend.emitter,
-      backend = backend,
-      super(backend.compiler);
-
-  HGraph build(CodegenWorkItem work) {
-    return measure(() {
-      Element element = work.element.implementation;
-      return compiler.withCurrentElement(element, () {
-        HInstruction.idCounter = 0;
-        SsaBuilder builder =
-            new SsaBuilder(backend, work, emitter.nativeEmitter);
-        HGraph graph;
-        ElementKind kind = element.kind;
-        if (kind == ElementKind.GENERATIVE_CONSTRUCTOR) {
-          graph = compileConstructor(builder, work);
-        } else if (kind == ElementKind.GENERATIVE_CONSTRUCTOR_BODY ||
-                   kind == ElementKind.FUNCTION ||
-                   kind == ElementKind.GETTER ||
-                   kind == ElementKind.SETTER) {
-          graph = builder.buildMethod(element);
-        } else if (kind == ElementKind.FIELD) {
-          if (element.isInstanceMember) {
-            assert(compiler.enableTypeAssertions);
-            graph = builder.buildCheckedSetter(element);
-          } else {
-            graph = builder.buildLazyInitializer(element);
-          }
-        } else {
-          compiler.internalError(element, 'Unexpected element kind $kind.');
-        }
-        assert(graph.isValid());
-        if (!identical(kind, ElementKind.FIELD)) {
-          FunctionElement function = element;
-          FunctionSignature signature = function.functionSignature;
-          signature.forEachOptionalParameter((ParameterElement parameter) {
-            // This ensures the default value will be computed.
-            ConstantValue constant =
-                backend.constants.getConstantForVariable(parameter).value;
-            CodegenRegistry registry = work.registry;
-            registry.registerCompileTimeConstant(constant);
-          });
-        }
-        if (compiler.tracer.isEnabled) {
-          String name;
-          if (element.isClassMember) {
-            String className = element.enclosingClass.name;
-            String memberName = element.name;
-            name = "$className.$memberName";
-            if (element.isGenerativeConstructorBody) {
-              name = "$name (body)";
-            }
-          } else {
-            name = "${element.name}";
-          }
-          compiler.tracer.traceCompilation(
-              name, work.compilationContext);
-          compiler.tracer.traceGraph('builder', graph);
-        }
-        return graph;
-      });
-    });
-  }
-
-  HGraph compileConstructor(SsaBuilder builder, CodegenWorkItem work) {
-    return builder.buildFactory(work.element);
-  }
-}
-
-/**
- * Keeps track of locals (including parameters and phis) when building. The
- * 'this' reference is treated as parameter and hence handled by this class,
- * too.
- */
-class LocalsHandler {
-  /**
-   * The values of locals that can be directly accessed (without redirections
-   * to boxes or closure-fields).
-   *
-   * [directLocals] is iterated, so it is "insertion ordered" to make the
-   * iteration order a function only of insertions and not a function of
-   * e.g. Element hash codes.  I'd prefer to use a SortedMap but some elements
-   * don't have source locations for [Elements.compareByPosition].
-   */
-  Map<Local, HInstruction> directLocals =
-      new Map<Local, HInstruction>();
-  Map<Local, CapturedVariable> redirectionMapping =
-      new Map<Local, CapturedVariable>();
-  SsaBuilder builder;
-  ClosureClassMap closureData;
-  Map<TypeVariableType, TypeVariableLocal> typeVariableLocals =
-      new Map<TypeVariableType, TypeVariableLocal>();
-  final ExecutableElement executableContext;
-
-  /// The class that defines the current type environment or null if no type
-  /// variables are in scope.
-  ClassElement get contextClass => executableContext.contextClass;
-
-  LocalsHandler(this.builder, this.executableContext);
-
-  /// Substituted type variables occurring in [type] into the context of
-  /// [contextClass].
-  DartType substInContext(DartType type) {
-    if (contextClass != null) {
-      ClassElement typeContext = Types.getClassContext(type);
-      if (typeContext != null) {
-        type = type.substByContext(
-            contextClass.asInstanceOf(typeContext));
-      }
-    }
-    return type;
-  }
-
-  get typesTask => builder.compiler.typesTask;
-
-  /**
-   * Creates a new [LocalsHandler] based on [other]. We only need to
-   * copy the [directLocals], since the other fields can be shared
-   * throughout the AST visit.
-   */
-  LocalsHandler.from(LocalsHandler other)
-      : directLocals = new Map<Local, HInstruction>.from(other.directLocals),
-        redirectionMapping = other.redirectionMapping,
-        executableContext = other.executableContext,
-        builder = other.builder,
-        closureData = other.closureData;
-
-  /**
-   * Redirects accesses from element [from] to element [to]. The [to] element
-   * must be a boxed variable or a variable that is stored in a closure-field.
-   */
-  void redirectElement(Local from, CapturedVariable to) {
-    assert(redirectionMapping[from] == null);
-    redirectionMapping[from] = to;
-    assert(isStoredInClosureField(from) || isBoxed(from));
-  }
-
-  HInstruction createBox() {
-    // TODO(floitsch): Clean up this hack. Should we create a box-object by
-    // just creating an empty object literal?
-    JavaScriptBackend backend = builder.backend;
-    HInstruction box = new HForeign(js.js.parseForeignJS('{}'),
-                                    backend.nonNullType,
-                                    <HInstruction>[]);
-    builder.add(box);
-    return box;
-  }
-
-  /**
-   * If the scope (function or loop) [node] has captured variables then this
-   * method creates a box and sets up the redirections.
-   */
-  void enterScope(ast.Node node, Element element) {
-    // See if any variable in the top-scope of the function is captured. If yes
-    // we need to create a box-object.
-    ClosureScope scopeData = closureData.capturingScopes[node];
-    if (scopeData == null) return;
-    HInstruction box;
-    // The scope has captured variables.
-    if (element != null && element.isGenerativeConstructorBody) {
-      // The box is passed as a parameter to a generative
-      // constructor body.
-      JavaScriptBackend backend = builder.backend;
-      box = builder.addParameter(scopeData.boxElement, backend.nonNullType);
-    } else {
-      box = createBox();
-    }
-    // Add the box to the known locals.
-    directLocals[scopeData.boxElement] = box;
-    // Make sure that accesses to the boxed locals go into the box. We also
-    // need to make sure that parameters are copied into the box if necessary.
-    scopeData.forEachCapturedVariable(
-        (LocalVariableElement from, BoxFieldElement to) {
-      // The [from] can only be a parameter for function-scopes and not
-      // loop scopes.
-      if (from.isParameter && !element.isGenerativeConstructorBody) {
-        // Now that the redirection is set up, the update to the local will
-        // write the parameter value into the box.
-        // Store the captured parameter in the box. Get the current value
-        // before we put the redirection in place.
-        // We don't need to update the local for a generative
-        // constructor body, because it receives a box that already
-        // contains the updates as the last parameter.
-        HInstruction instruction = readLocal(from);
-        redirectElement(from, to);
-        updateLocal(from, instruction);
-      } else {
-        redirectElement(from, to);
-      }
-    });
-  }
-
-  /**
-   * Replaces the current box with a new box and copies over the given list
-   * of elements from the old box into the new box.
-   */
-  void updateCaptureBox(BoxLocal boxElement,
-                        List<LocalVariableElement> toBeCopiedElements) {
-    // Create a new box and copy over the values from the old box into the
-    // new one.
-    HInstruction oldBox = readLocal(boxElement);
-    HInstruction newBox = createBox();
-    for (LocalVariableElement boxedVariable in toBeCopiedElements) {
-      // [readLocal] uses the [boxElement] to find its box. By replacing it
-      // behind its back we can still get to the old values.
-      updateLocal(boxElement, oldBox);
-      HInstruction oldValue = readLocal(boxedVariable);
-      updateLocal(boxElement, newBox);
-      updateLocal(boxedVariable, oldValue);
-    }
-    updateLocal(boxElement, newBox);
-  }
-
-  /**
-   * Documentation wanted -- johnniwinther
-   *
-   * Invariant: [function] must be an implementation element.
-   */
-  void startFunction(Element element, ast.Node node) {
-    assert(invariant(element, element.isImplementation));
-    Compiler compiler = builder.compiler;
-    closureData = compiler.closureToClassMapper.computeClosureToClassMapping(
-            element, node, builder.elements);
-
-    if (element is FunctionElement) {
-      FunctionElement functionElement = element;
-      FunctionSignature params = functionElement.functionSignature;
-      ClosureScope scopeData = closureData.capturingScopes[node];
-      params.orderedForEachParameter((ParameterElement parameterElement) {
-        if (element.isGenerativeConstructorBody) {
-          if (scopeData != null &&
-              scopeData.isCapturedVariable(parameterElement)) {
-            // The parameter will be a field in the box passed as the
-            // last parameter. So no need to have it.
-            return;
-          }
-        }
-        HInstruction parameter = builder.addParameter(
-            parameterElement,
-            TypeMaskFactory.inferredTypeForElement(parameterElement, compiler));
-        builder.parameters[parameterElement] = parameter;
-        directLocals[parameterElement] = parameter;
-      });
-    }
-
-    enterScope(node, element);
-
-    // If the freeVariableMapping is not empty, then this function was a
-    // nested closure that captures variables. Redirect the captured
-    // variables to fields in the closure.
-    closureData.forEachFreeVariable((Local from, CapturedVariable to) {
-      redirectElement(from, to);
-    });
-    JavaScriptBackend backend = compiler.backend;
-    if (closureData.isClosure) {
-      // Inside closure redirect references to itself to [:this:].
-      HThis thisInstruction = new HThis(closureData.thisLocal,
-                                        backend.nonNullType);
-      builder.graph.thisInstruction = thisInstruction;
-      builder.graph.entry.addAtEntry(thisInstruction);
-      updateLocal(closureData.closureElement, thisInstruction);
-    } else if (element.isInstanceMember) {
-      // Once closures have been mapped to classes their instance members might
-      // not have any thisElement if the closure was created inside a static
-      // context.
-      HThis thisInstruction = new HThis(
-          closureData.thisLocal, builder.getTypeOfThis());
-      builder.graph.thisInstruction = thisInstruction;
-      builder.graph.entry.addAtEntry(thisInstruction);
-      directLocals[closureData.thisLocal] = thisInstruction;
-    }
-
-    // If this method is an intercepted method, add the extra
-    // parameter to it, that is the actual receiver for intercepted
-    // classes, or the same as [:this:] for non-intercepted classes.
-    ClassElement cls = element.enclosingClass;
-
-    // When the class extends a native class, the instance is pre-constructed
-    // and passed to the generative constructor factory function as a parameter.
-    // Instead of allocating and initializing the object, the constructor
-    // 'upgrades' the native subclass object by initializing the Dart fields.
-    bool isNativeUpgradeFactory = element.isGenerativeConstructor
-        && Elements.isNativeOrExtendsNative(cls);
-    if (backend.isInterceptedMethod(element)) {
-      bool isInterceptorClass = backend.isInterceptorClass(cls.declaration);
-      String name = isInterceptorClass ? 'receiver' : '_';
-      SyntheticLocal parameter = new SyntheticLocal(name, executableContext);
-      HParameterValue value =
-          new HParameterValue(parameter, builder.getTypeOfThis());
-      builder.graph.explicitReceiverParameter = value;
-      builder.graph.entry.addAfter(
-          directLocals[closureData.thisLocal], value);
-      if (isInterceptorClass) {
-        // Only use the extra parameter in intercepted classes.
-        directLocals[closureData.thisLocal] = value;
-      }
-    } else if (isNativeUpgradeFactory) {
-      SyntheticLocal parameter =
-          new SyntheticLocal('receiver', executableContext);
-      // Unlike `this`, receiver is nullable since direct calls to generative
-      // constructor call the constructor with `null`.
-      ClassWorld classWorld = compiler.world;
-      HParameterValue value =
-          new HParameterValue(parameter, new TypeMask.exact(cls, classWorld));
-      builder.graph.explicitReceiverParameter = value;
-      builder.graph.entry.addAtEntry(value);
-    }
-  }
-
-  /**
-   * Returns true if the local can be accessed directly. Boxed variables or
-   * captured variables that are stored in the closure-field return [:false:].
-   */
-  bool isAccessedDirectly(Local local) {
-    assert(local != null);
-    return !redirectionMapping.containsKey(local)
-        && !closureData.usedVariablesInTry.contains(local);
-  }
-
-  bool isStoredInClosureField(Local local) {
-    assert(local != null);
-    if (isAccessedDirectly(local)) return false;
-    CapturedVariable redirectTarget = redirectionMapping[local];
-    if (redirectTarget == null) return false;
-    return redirectTarget is ClosureFieldElement;
-  }
-
-  bool isBoxed(Local local) {
-    if (isAccessedDirectly(local)) return false;
-    if (isStoredInClosureField(local)) return false;
-    return redirectionMapping.containsKey(local);
-  }
-
-  bool isUsedInTry(Local local) {
-    return closureData.usedVariablesInTry.contains(local);
-  }
-
-  /**
-   * Returns an [HInstruction] for the given element. If the element is
-   * boxed or stored in a closure then the method generates code to retrieve
-   * the value.
-   */
-  HInstruction readLocal(Local local) {
-    if (isAccessedDirectly(local)) {
-      if (directLocals[local] == null) {
-        if (local is TypeVariableElement) {
-          builder.compiler.internalError(builder.compiler.currentElement,
-              "Runtime type information not available for $local.");
-        } else {
-          builder.compiler.internalError(local,
-              "Cannot find value $local.");
-        }
-      }
-      return directLocals[local];
-    } else if (isStoredInClosureField(local)) {
-      ClosureFieldElement redirect = redirectionMapping[local];
-      HInstruction receiver = readLocal(closureData.closureElement);
-      TypeMask type = local is BoxLocal
-          ? builder.backend.nonNullType
-          : builder.getTypeOfCapturedVariable(redirect);
-      HInstruction fieldGet = new HFieldGet(redirect, receiver, type);
-      builder.add(fieldGet);
-      return fieldGet;
-    } else if (isBoxed(local)) {
-      BoxFieldElement redirect = redirectionMapping[local];
-      // In the function that declares the captured variable the box is
-      // accessed as direct local. Inside the nested closure the box is
-      // accessed through a closure-field.
-      // Calling [readLocal] makes sure we generate the correct code to get
-      // the box.
-      HInstruction box = readLocal(redirect.box);
-      HInstruction lookup = new HFieldGet(
-          redirect, box, builder.getTypeOfCapturedVariable(redirect));
-      builder.add(lookup);
-      return lookup;
-    } else {
-      assert(isUsedInTry(local));
-      HLocalValue localValue = getLocal(local);
-      HInstruction instruction = new HLocalGet(
-          local, localValue, builder.backend.dynamicType);
-      builder.add(instruction);
-      return instruction;
-    }
-  }
-
-  HInstruction readThis() {
-    HInstruction res = readLocal(closureData.thisLocal);
-    if (res.instructionType == null) {
-      res.instructionType = builder.getTypeOfThis();
-    }
-    return res;
-  }
-
-  HLocalValue getLocal(Local local) {
-    // If the element is a parameter, we already have a
-    // HParameterValue for it. We cannot create another one because
-    // it could then have another name than the real parameter. And
-    // the other one would not know it is just a copy of the real
-    // parameter.
-    if (local is ParameterElement) return builder.parameters[local];
-
-    return builder.activationVariables.putIfAbsent(local, () {
-      JavaScriptBackend backend = builder.backend;
-      HLocalValue localValue = new HLocalValue(local, backend.nonNullType);
-      builder.graph.entry.addAtExit(localValue);
-      return localValue;
-    });
-  }
-
-  Local getTypeVariableAsLocal(TypeVariableType type) {
-    return typeVariableLocals.putIfAbsent(type, () {
-      return new TypeVariableLocal(type, executableContext);
-    });
-  }
-
-  /**
-   * Sets the [element] to [value]. If the element is boxed or stored in a
-   * closure then the method generates code to set the value.
-   */
-  void updateLocal(Local local, HInstruction value) {
-    assert(!isStoredInClosureField(local));
-    if (isAccessedDirectly(local)) {
-      directLocals[local] = value;
-    } else if (isBoxed(local)) {
-      BoxFieldElement redirect = redirectionMapping[local];
-      // The box itself could be captured, or be local. A local variable that
-      // is captured will be boxed, but the box itself will be a local.
-      // Inside the closure the box is stored in a closure-field and cannot
-      // be accessed directly.
-      HInstruction box = readLocal(redirect.box);
-      builder.add(new HFieldSet(redirect, box, value));
-    } else {
-      assert(isUsedInTry(local));
-      HLocalValue localValue = getLocal(local);
-      builder.add(new HLocalSet(local, localValue, value));
-    }
-  }
-
-  /**
-   * This function, startLoop, must be called before visiting any children of
-   * the loop. In particular it needs to be called before executing the
-   * initializers.
-   *
-   * The [LocalsHandler] will make the boxes and updates at the right moment.
-   * The builder just needs to call [enterLoopBody] and [enterLoopUpdates]
-   * (for [ast.For] loops) at the correct places. For phi-handling
-   * [beginLoopHeader] and [endLoop] must also be called.
-   *
-   * The correct place for the box depends on the given loop. In most cases
-   * the box will be created when entering the loop-body: while, do-while, and
-   * for-in (assuming the call to [:next:] is inside the body) can always be
-   * constructed this way.
-   *
-   * Things are slightly more complicated for [ast.For] loops. If no declared
-   * loop variable is boxed then the loop-body approach works here too. If a
-   * loop-variable is boxed we need to introduce a new box for the
-   * loop-variable before we enter the initializer so that the initializer
-   * writes the values into the box. In any case we need to create the box
-   * before the condition since the condition could box the variable.
-   * Since the first box is created outside the actual loop we have a second
-   * location where a box is created: just before the updates. This is
-   * necessary since updates are considered to be part of the next iteration
-   * (and can again capture variables).
-   *
-   * For example the following Dart code prints 1 3 -- 3 4.
-   *
-   *     var fs = [];
-   *     for (var i = 0; i < 3; (f() { fs.add(f); print(i); i++; })()) {
-   *       i++;
-   *     }
-   *     print("--");
-   *     for (var i = 0; i < 2; i++) fs[i]();
-   *
-   * We solve this by emitting the following code (only for [ast.For] loops):
-   *  <Create box>    <== move the first box creation outside the loop.
-   *  <initializer>;
-   *  loop-entry:
-   *    if (!<condition>) goto loop-exit;
-   *    <body>
-   *    <update box>  // create a new box and copy the captured loop-variables.
-   *    <updates>
-   *    goto loop-entry;
-   *  loop-exit:
-   */
-  void startLoop(ast.Node node) {
-    ClosureScope scopeData = closureData.capturingScopes[node];
-    if (scopeData == null) return;
-    if (scopeData.hasBoxedLoopVariables()) {
-      // If there are boxed loop variables then we set up the box and
-      // redirections already now. This way the initializer can write its
-      // values into the box.
-      // For other loops the box will be created when entering the body.
-      enterScope(node, null);
-    }
-  }
-
-  /**
-   * Create phis at the loop entry for local variables (ready for the values
-   * from the back edge).  Populate the phis with the current values.
-   */
-  void beginLoopHeader(HBasicBlock loopEntry) {
-    // Create a copy because we modify the map while iterating over it.
-    Map<Local, HInstruction> savedDirectLocals =
-        new Map<Local, HInstruction>.from(directLocals);
-
-    JavaScriptBackend backend = builder.backend;
-    // Create phis for all elements in the definitions environment.
-    savedDirectLocals.forEach((Local local,
-                               HInstruction instruction) {
-      if (isAccessedDirectly(local)) {
-        // We know 'this' cannot be modified.
-        if (local != closureData.thisLocal) {
-          HPhi phi = new HPhi.singleInput(
-              local, instruction, backend.dynamicType);
-          loopEntry.addPhi(phi);
-          directLocals[local] = phi;
-        } else {
-          directLocals[local] = instruction;
-        }
-      }
-    });
-  }
-
-  void enterLoopBody(ast.Node node) {
-    ClosureScope scopeData = closureData.capturingScopes[node];
-    if (scopeData == null) return;
-    // If there are no declared boxed loop variables then we did not create the
-    // box before the initializer and we have to create the box now.
-    if (!scopeData.hasBoxedLoopVariables()) {
-      enterScope(node, null);
-    }
-  }
-
-  void enterLoopUpdates(ast.Node node) {
-    // If there are declared boxed loop variables then the updates might have
-    // access to the box and we must switch to a new box before executing the
-    // updates.
-    // In all other cases a new box will be created when entering the body of
-    // the next iteration.
-    ClosureScope scopeData = closureData.capturingScopes[node];
-    if (scopeData == null) return;
-    if (scopeData.hasBoxedLoopVariables()) {
-      updateCaptureBox(scopeData.boxElement, scopeData.boxedLoopVariables);
-    }
-  }
-
-  /**
-   * Goes through the phis created in beginLoopHeader entry and adds the
-   * input from the back edge (from the current value of directLocals) to them.
-   */
-  void endLoop(HBasicBlock loopEntry) {
-    // If the loop has an aborting body, we don't update the loop
-    // phis.
-    if (loopEntry.predecessors.length == 1) return;
-    loopEntry.forEachPhi((HPhi phi) {
-      Local element = phi.sourceElement;
-      HInstruction postLoopDefinition = directLocals[element];
-      phi.addInput(postLoopDefinition);
-    });
-  }
-
-  /**
-   * Merge [otherLocals] into this locals handler, creating phi-nodes when
-   * there is a conflict.
-   * If a phi node is necessary, it will use this handler's instruction as the
-   * first input, and the otherLocals instruction as the second.
-   */
-  void mergeWith(LocalsHandler otherLocals, HBasicBlock joinBlock) {
-    // If an element is in one map but not the other we can safely
-    // ignore it. It means that a variable was declared in the
-    // block. Since variable declarations are scoped the declared
-    // variable cannot be alive outside the block. Note: this is only
-    // true for nodes where we do joins.
-    Map<Local, HInstruction> joinedLocals =
-        new Map<Local, HInstruction>();
-    JavaScriptBackend backend = builder.backend;
-    otherLocals.directLocals.forEach((Local local,
-                                      HInstruction instruction) {
-      // We know 'this' cannot be modified.
-      if (local == closureData.thisLocal) {
-        assert(directLocals[local] == instruction);
-        joinedLocals[local] = instruction;
-      } else {
-        HInstruction mine = directLocals[local];
-        if (mine == null) return;
-        if (identical(instruction, mine)) {
-          joinedLocals[local] = instruction;
-        } else {
-          HInstruction phi = new HPhi.manyInputs(
-              local, <HInstruction>[mine, instruction], backend.dynamicType);
-          joinBlock.addPhi(phi);
-          joinedLocals[local] = phi;
-        }
-      }
-    });
-    directLocals = joinedLocals;
-  }
-
-  /**
-   * When control flow merges, this method can be used to merge several
-   * localsHandlers into a new one using phis.  The new localsHandler is
-   * returned.  Unless it is also in the list, the current localsHandler is not
-   * used for its values, only for its declared variables. This is a way to
-   * exclude local values from the result when they are no longer in scope.
-   */
-  LocalsHandler mergeMultiple(List<LocalsHandler> localsHandlers,
-                              HBasicBlock joinBlock) {
-    assert(localsHandlers.length > 0);
-    if (localsHandlers.length == 1) return localsHandlers[0];
-    Map<Local, HInstruction> joinedLocals =
-        new Map<Local, HInstruction>();
-    HInstruction thisValue = null;
-    JavaScriptBackend backend = builder.backend;
-    directLocals.forEach((Local local, HInstruction instruction) {
-      if (local != closureData.thisLocal) {
-        HPhi phi = new HPhi.noInputs(local, backend.dynamicType);
-        joinedLocals[local] = phi;
-        joinBlock.addPhi(phi);
-      } else {
-        // We know that "this" never changes, if it's there.
-        // Save it for later. While merging, there is no phi for "this",
-        // so we don't have to special case it in the merge loop.
-        thisValue = instruction;
-      }
-    });
-    for (LocalsHandler handler in localsHandlers) {
-      handler.directLocals.forEach((Local local,
-                                    HInstruction instruction) {
-        HPhi phi = joinedLocals[local];
-        if (phi != null) {
-          phi.addInput(instruction);
-        }
-      });
-    }
-    if (thisValue != null) {
-      // If there was a "this" for the scope, add it to the new locals.
-      joinedLocals[closureData.thisLocal] = thisValue;
-    }
-
-    // Remove locals that are not in all handlers.
-    directLocals = new Map<Local, HInstruction>();
-    joinedLocals.forEach((Local local,
-                          HInstruction instruction) {
-      if (local != closureData.thisLocal
-          && instruction.inputs.length != localsHandlers.length) {
-        joinBlock.removePhi(instruction);
-      } else {
-        directLocals[local] = instruction;
-      }
-    });
-    return this;
-  }
-}
-
-
-// Represents a single break/continue instruction.
-class JumpHandlerEntry {
-  final HJump jumpInstruction;
-  final LocalsHandler locals;
-  bool isBreak() => jumpInstruction is HBreak;
-  bool isContinue() => jumpInstruction is HContinue;
-  JumpHandlerEntry(this.jumpInstruction, this.locals);
-}
-
-
-abstract class JumpHandler {
-  factory JumpHandler(SsaBuilder builder, JumpTarget target) {
-    return new TargetJumpHandler(builder, target);
-  }
-  void generateBreak([LabelDefinition label]);
-  void generateContinue([LabelDefinition label]);
-  void forEachBreak(void action(HBreak instruction, LocalsHandler locals));
-  void forEachContinue(void action(HContinue instruction,
-                                   LocalsHandler locals));
-  bool hasAnyContinue();
-  bool hasAnyBreak();
-  void close();
-  final JumpTarget target;
-  List<LabelDefinition> labels();
-}
-
-// Insert break handler used to avoid null checks when a target isn't
-// used as the target of a break, and therefore doesn't need a break
-// handler associated with it.
-class NullJumpHandler implements JumpHandler {
-  final Compiler compiler;
-
-  NullJumpHandler(this.compiler);
-
-  void generateBreak([LabelDefinition label]) {
-    compiler.internalError(CURRENT_ELEMENT_SPANNABLE,
-        'NullJumpHandler.generateBreak should not be called.');
-  }
-
-  void generateContinue([LabelDefinition label]) {
-    compiler.internalError(CURRENT_ELEMENT_SPANNABLE,
-        'NullJumpHandler.generateContinue should not be called.');
-  }
-
-  void forEachBreak(Function ignored) { }
-  void forEachContinue(Function ignored) { }
-  void close() { }
-  bool hasAnyContinue() => false;
-  bool hasAnyBreak() => false;
-
-  List<LabelDefinition> labels() => const <LabelDefinition>[];
-  JumpTarget get target => null;
-}
-
-// Records breaks until a target block is available.
-// Breaks are always forward jumps.
-// Continues in loops are implemented as breaks of the body.
-// Continues in switches is currently not handled.
-class TargetJumpHandler implements JumpHandler {
-  final SsaBuilder builder;
-  final JumpTarget target;
-  final List<JumpHandlerEntry> jumps;
-
-  TargetJumpHandler(SsaBuilder builder, this.target)
-      : this.builder = builder,
-        jumps = <JumpHandlerEntry>[] {
-    assert(builder.jumpTargets[target] == null);
-    builder.jumpTargets[target] = this;
-  }
-
-  void generateBreak([LabelDefinition label]) {
-    HInstruction breakInstruction;
-    if (label == null) {
-      breakInstruction = new HBreak(target);
-    } else {
-      breakInstruction = new HBreak.toLabel(label);
-    }
-    LocalsHandler locals = new LocalsHandler.from(builder.localsHandler);
-    builder.close(breakInstruction);
-    jumps.add(new JumpHandlerEntry(breakInstruction, locals));
-  }
-
-  void generateContinue([LabelDefinition label]) {
-    HInstruction continueInstruction;
-    if (label == null) {
-      continueInstruction = new HContinue(target);
-    } else {
-      continueInstruction = new HContinue.toLabel(label);
-      // Switch case continue statements must be handled by the
-      // [SwitchCaseJumpHandler].
-      assert(label.target.statement is! ast.SwitchCase);
-    }
-    LocalsHandler locals = new LocalsHandler.from(builder.localsHandler);
-    builder.close(continueInstruction);
-    jumps.add(new JumpHandlerEntry(continueInstruction, locals));
-  }
-
-  void forEachBreak(Function action) {
-    for (JumpHandlerEntry entry in jumps) {
-      if (entry.isBreak()) action(entry.jumpInstruction, entry.locals);
-    }
-  }
-
-  void forEachContinue(Function action) {
-    for (JumpHandlerEntry entry in jumps) {
-      if (entry.isContinue()) action(entry.jumpInstruction, entry.locals);
-    }
-  }
-
-  bool hasAnyContinue() {
-    for (JumpHandlerEntry entry in jumps) {
-      if (entry.isContinue()) return true;
-    }
-    return false;
-  }
-
-  bool hasAnyBreak() {
-    for (JumpHandlerEntry entry in jumps) {
-      if (entry.isBreak()) return true;
-    }
-    return false;
-  }
-
-  void close() {
-    // The mapping from TargetElement to JumpHandler is no longer needed.
-    builder.jumpTargets.remove(target);
-  }
-
-  List<LabelDefinition> labels() {
-    List<LabelDefinition> result = null;
-    for (LabelDefinition element in target.labels) {
-      if (result == null) result = <LabelDefinition>[];
-      result.add(element);
-    }
-    return (result == null) ? const <LabelDefinition>[] : result;
-  }
-}
-
-/// Special [JumpHandler] implementation used to handle continue statements
-/// targeting switch cases.
-class SwitchCaseJumpHandler extends TargetJumpHandler {
-  /// Map from switch case targets to indices used to encode the flow of the
-  /// switch case loop.
-  final Map<JumpTarget, int> targetIndexMap = new Map<JumpTarget, int>();
-
-  SwitchCaseJumpHandler(SsaBuilder builder,
-                        JumpTarget target,
-                        ast.SwitchStatement node)
-      : super(builder, target) {
-    // The switch case indices must match those computed in
-    // [SsaFromAstMixin.buildSwitchCaseConstants].
-    // Switch indices are 1-based so we can bypass the synthetic loop when no
-    // cases match simply by branching on the index (which defaults to null).
-    int switchIndex = 1;
-    for (ast.SwitchCase switchCase in node.cases) {
-      for (ast.Node labelOrCase in switchCase.labelsAndCases) {
-        ast.Node label = labelOrCase.asLabel();
-        if (label != null) {
-          LabelDefinition labelElement =
-              builder.elements.getLabelDefinition(label);
-          if (labelElement != null && labelElement.isContinueTarget) {
-            JumpTarget continueTarget = labelElement.target;
-            targetIndexMap[continueTarget] = switchIndex;
-            assert(builder.jumpTargets[continueTarget] == null);
-            builder.jumpTargets[continueTarget] = this;
-          }
-        }
-      }
-      switchIndex++;
-    }
-  }
-
-  void generateBreak([LabelDefinition label]) {
-    if (label == null) {
-      // Creates a special break instruction for the synthetic loop generated
-      // for a switch statement with continue statements. See
-      // [SsaFromAstMixin.buildComplexSwitchStatement] for detail.
-
-      HInstruction breakInstruction =
-          new HBreak(target, breakSwitchContinueLoop: true);
-      LocalsHandler locals = new LocalsHandler.from(builder.localsHandler);
-      builder.close(breakInstruction);
-      jumps.add(new JumpHandlerEntry(breakInstruction, locals));
-    } else {
-      super.generateBreak(label);
-    }
-  }
-
-  bool isContinueToSwitchCase(LabelDefinition label) {
-    return label != null && targetIndexMap.containsKey(label.target);
-  }
-
-  void generateContinue([LabelDefinition label]) {
-    if (isContinueToSwitchCase(label)) {
-      // Creates the special instructions 'label = i; continue l;' used in
-      // switch statements with continue statements. See
-      // [SsaFromAstMixin.buildComplexSwitchStatement] for detail.
-
-      assert(label != null);
-      HInstruction value = builder.graph.addConstantInt(
-          targetIndexMap[label.target],
-          builder.compiler);
-      builder.localsHandler.updateLocal(target, value);
-
-      assert(label.target.labels.contains(label));
-      HInstruction continueInstruction = new HContinue(target);
-      LocalsHandler locals = new LocalsHandler.from(builder.localsHandler);
-      builder.close(continueInstruction);
-      jumps.add(new JumpHandlerEntry(continueInstruction, locals));
-    } else {
-      super.generateContinue(label);
-    }
-  }
-
-  void close() {
-    // The mapping from TargetElement to JumpHandler is no longer needed.
-    for (JumpTarget target in targetIndexMap.keys) {
-      builder.jumpTargets.remove(target);
-    }
-    super.close();
-  }
-}
-
-/**
- * This class builds SSA nodes for functions represented in AST.
- */
-class SsaBuilder extends ResolvedVisitor {
-  final Compiler compiler;
-  final JavaScriptBackend backend;
-  final ConstantSystem constantSystem;
-  final CodegenWorkItem work;
-  final RuntimeTypes rti;
-
-  /* This field is used by the native handler. */
-  final NativeEmitter nativeEmitter;
-
-  final HGraph graph = new HGraph();
-
-  /**
-   * The current block to add instructions to. Might be null, if we are
-   * visiting dead code, but see [isReachable].
-   */
-  HBasicBlock _current;
-
-  HBasicBlock get current => _current;
-
-  void set current(c) {
-    isReachable = c != null;
-    _current = c;
-  }
-
-  /**
-   * The most recently opened block. Has the same value as [current] while
-   * the block is open, but unlike [current], it isn't cleared when the
-   * current block is closed.
-   */
-  HBasicBlock lastOpenedBlock;
-
-  /**
-   * Indicates whether the current block is dead (because it has a throw or a
-   * return further up). If this is false, then [current] may be null. If the
-   * block is dead then it may also be aborted, but for simplicity we only
-   * abort on statement boundaries, not in the middle of expressions. See
-   * isAborted.
-   */
-  bool isReachable = true;
-
-  /**
-   * True if we are visiting the expression of a throw statement; we assume this
-   * is a slow path.
-   */
-  bool inExpressionOfThrow = false;
-
-  /**
-   * The loop nesting is consulted when inlining a function invocation in
-   * [tryInlineMethod]. The inlining heuristics take this information into
-   * account.
-   */
-  int loopNesting = 0;
-
-  /**
-   * This stack contains declaration elements of the functions being built
-   * or inlined by this builder.
-   */
-  final List<Element> sourceElementStack = <Element>[];
-
-  LocalsHandler localsHandler;
-
-  HInstruction rethrowableException;
-
-  HParameterValue lastAddedParameter;
-
-  Map<ParameterElement, HInstruction> parameters =
-      <ParameterElement, HInstruction>{};
-
-  Map<JumpTarget, JumpHandler> jumpTargets = <JumpTarget, JumpHandler>{};
-
-  /**
-   * Variables stored in the current activation. These variables are
-   * being updated in try/catch blocks, and should be
-   * accessed indirectly through [HLocalGet] and [HLocalSet].
-   */
-  Map<Local, HLocalValue> activationVariables =
-      <Local, HLocalValue>{};
-
-  // We build the Ssa graph by simulating a stack machine.
-  List<HInstruction> stack = <HInstruction>[];
-
-  SsaBuilder(JavaScriptBackend backend,
-             CodegenWorkItem work,
-             this.nativeEmitter)
-    : this.compiler = backend.compiler,
-      this.backend = backend,
-      this.constantSystem = backend.constantSystem,
-      this.work = work,
-      this.rti = backend.rti,
-      super(work.resolutionTree) {
-    localsHandler = new LocalsHandler(this, work.element);
-    sourceElementStack.add(work.element);
-  }
-
-  CodegenRegistry get registry => work.registry;
-
-  /// Returns the current source element.
-  ///
-  /// The returned element is a declaration element.
-  // TODO(johnniwinther): Check that all usages of sourceElement agree on
-  // implementation/declaration distinction.
-  Element get sourceElement => sourceElementStack.last;
-
-  HBasicBlock addNewBlock() {
-    HBasicBlock block = graph.addNewBlock();
-    // If adding a new block during building of an expression, it is due to
-    // conditional expressions or short-circuit logical operators.
-    return block;
-  }
-
-  void open(HBasicBlock block) {
-    block.open();
-    current = block;
-    lastOpenedBlock = block;
-  }
-
-  HBasicBlock close(HControlFlow end) {
-    HBasicBlock result = current;
-    current.close(end);
-    current = null;
-    return result;
-  }
-
-  HBasicBlock closeAndGotoExit(HControlFlow end) {
-    HBasicBlock result = current;
-    current.close(end);
-    current = null;
-    result.addSuccessor(graph.exit);
-    return result;
-  }
-
-  void goto(HBasicBlock from, HBasicBlock to) {
-    from.close(new HGoto());
-    from.addSuccessor(to);
-  }
-
-  bool isAborted() {
-    return current == null;
-  }
-
-  /**
-   * Creates a new block, transitions to it from any current block, and
-   * opens the new block.
-   */
-  HBasicBlock openNewBlock() {
-    HBasicBlock newBlock = addNewBlock();
-    if (!isAborted()) goto(current, newBlock);
-    open(newBlock);
-    return newBlock;
-  }
-
-  void add(HInstruction instruction) {
-    current.add(instruction);
-  }
-
-  void addWithPosition(HInstruction instruction, ast.Node node) {
-    add(attachPosition(instruction, node));
-  }
-
-  SourceFile currentSourceFile() {
-    return sourceElement.implementation.compilationUnit.script.file;
-  }
-
-  void checkValidSourceFileLocation(
-      SourceFileLocation location, SourceFile sourceFile, int offset) {
-    if (!location.isValid()) {
-      throw MessageKind.INVALID_SOURCE_FILE_LOCATION.message(
-          {'offset': offset,
-           'fileName': sourceFile.filename,
-           'length': sourceFile.length});
-    }
-  }
-
-  /**
-   * Returns a complete argument list for a call of [function].
-   */
-  List<HInstruction> completeSendArgumentsList(
-      FunctionElement function,
-      Selector selector,
-      List<HInstruction> providedArguments,
-      ast.Node currentNode) {
-    assert(invariant(function, function.isImplementation));
-    assert(providedArguments != null);
-
-    bool isInstanceMember = function.isInstanceMember;
-    // For static calls, [providedArguments] is complete, default arguments
-    // have been included if necessary, see [addStaticSendArgumentsToList].
-    if (!isInstanceMember
-        || currentNode == null // In erroneous code, currentNode can be null.
-        || providedArgumentsKnownToBeComplete(currentNode)
-        || function.isGenerativeConstructorBody
-        || selector.isGetter) {
-      // For these cases, the provided argument list is known to be complete.
-      return providedArguments;
-    } else {
-      return completeDynamicSendArgumentsList(
-          selector, function, providedArguments);
-    }
-  }
-
-  /**
-   * Returns a complete argument list for a dynamic call of [function]. The
-   * initial argument list [providedArguments], created by
-   * [addDynamicSendArgumentsToList], does not include values for default
-   * arguments used in the call. The reason is that the target function (which
-   * defines the defaults) is not known.
-   *
-   * However, inlining can only be performed when the target function can be
-   * resolved statically. The defaults can therefore be included at this point.
-   *
-   * The [providedArguments] list contains first all positional arguments, then
-   * the provided named arguments (the named arguments that are defined in the
-   * [selector]) in a specific order (see [addDynamicSendArgumentsToList]).
-   */
-  List<HInstruction> completeDynamicSendArgumentsList(
-      Selector selector,
-      FunctionElement function,
-      List<HInstruction> providedArguments) {
-    assert(selector.applies(function, compiler.world));
-    FunctionSignature signature = function.functionSignature;
-    List<HInstruction> compiledArguments = new List<HInstruction>(
-        signature.parameterCount + 1); // Plus one for receiver.
-
-    compiledArguments[0] = providedArguments[0]; // Receiver.
-    int index = 1;
-    for (; index <= signature.requiredParameterCount; index++) {
-      compiledArguments[index] = providedArguments[index];
-    }
-    if (!signature.optionalParametersAreNamed) {
-      signature.forEachOptionalParameter((element) {
-        if (index < providedArguments.length) {
-          compiledArguments[index] = providedArguments[index];
-        } else {
-          compiledArguments[index] =
-              handleConstantForOptionalParameter(element);
-        }
-        index++;
-      });
-    } else {
-      /* Example:
-       *   void foo(a, {b, d, c})
-       *   foo(0, d = 1, b = 2)
-       *
-       * providedArguments = [0, 2, 1]
-       * selectorArgumentNames = [b, d]
-       * signature.orderedOptionalParameters = [b, c, d]
-       *
-       * For each parameter name in the signature, if the argument name matches
-       * we use the next provided argument, otherwise we get the default.
-       */
-      List<String> selectorArgumentNames = selector.getOrderedNamedArguments();
-      int namedArgumentIndex = 0;
-      int firstProvidedNamedArgument = index;
-      signature.orderedOptionalParameters.forEach((element) {
-        if (namedArgumentIndex < selectorArgumentNames.length &&
-            element.name == selectorArgumentNames[namedArgumentIndex]) {
-          // The named argument was provided in the function invocation.
-          compiledArguments[index] = providedArguments[
-              firstProvidedNamedArgument + namedArgumentIndex++];
-        } else {
-          compiledArguments[index] =
-              handleConstantForOptionalParameter(element);
-        }
-        index++;
-      });
-    }
-    return compiledArguments;
-  }
-
-  /**
-   * Try to inline [element] within the currect context of the builder. The
-   * insertion point is the state of the builder.
-   */
-  bool tryInlineMethod(Element element,
-                       Selector selector,
-                       List<HInstruction> providedArguments,
-                       ast.Node currentNode) {
-    // TODO(johnniwinther): Register this on the [registry]. Currently the
-    // [CodegenRegistry] calls the enqueuer, but [element] should _not_ be
-    // enqueued.
-    backend.registerStaticUse(element, compiler.enqueuer.codegen);
-
-    // Ensure that [element] is an implementation element.
-    element = element.implementation;
-    FunctionElement function = element;
-    bool insideLoop = loopNesting > 0 || graph.calledInLoop;
-
-    // Bail out early if the inlining decision is in the cache and we can't
-    // inline (no need to check the hard constraints).
-    bool cachedCanBeInlined =
-        backend.inlineCache.canInline(function, insideLoop: insideLoop);
-    if (cachedCanBeInlined == false) return false;
-
-    bool meetsHardConstraints() {
-      // Don't inline from one output unit to another. If something is deferred
-      // it is to save space in the loading code.
-      if (!compiler.deferredLoadTask
-          .inSameOutputUnit(element,compiler.currentElement)) {
-        return false;
-      }
-      if (compiler.disableInlining) return false;
-
-      assert(selector != null
-             || Elements.isStaticOrTopLevel(element)
-             || element.isGenerativeConstructorBody);
-      if (selector != null && !selector.applies(function, compiler.world)) {
-        return false;
-      }
-
-      // Don't inline operator== methods if the parameter can be null.
-      if (element.name == '==') {
-        if (element.enclosingClass != compiler.objectClass
-            && providedArguments[1].canBeNull()) {
-          return false;
-        }
-      }
-
-      // Generative constructors of native classes should not be called directly
-      // and have an extra argument that causes problems with inlining.
-      if (element.isGenerativeConstructor
-          && Elements.isNativeOrExtendsNative(element.enclosingClass)) {
-        return false;
-      }
-
-      // A generative constructor body is not seen by global analysis,
-      // so we should not query for its type.
-      if (!element.isGenerativeConstructorBody) {
-        // Don't inline if the return type was inferred to be non-null empty.
-        // This means that the function always throws an exception.
-        TypeMask returnType =
-            compiler.typesTask.getGuaranteedReturnTypeOfElement(element);
-        if (returnType != null
-            && returnType.isEmpty
-            && !returnType.isNullable) {
-          isReachable = false;
-          return false;
-        }
-      }
-
-      return true;
-    }
-
-    bool heuristicSayGoodToGo() {
-      // Don't inline recursivly
-      if (inliningStack.any((entry) => entry.function == function)) {
-        return false;
-      }
-
-      if (inExpressionOfThrow) return false;
-
-      if (element.isSynthesized) return true;
-
-      if (cachedCanBeInlined == true) return cachedCanBeInlined;
-
-      if (backend.functionsToAlwaysInline.contains(function)) {
-        // Inline this function regardless of it's size.
-        assert(InlineWeeder.canBeInlined(function.node, -1, false,
-                                         allowLoops: true));
-        return true;
-      }
-
-      int numParameters = function.functionSignature.parameterCount;
-      int maxInliningNodes;
-      bool useMaxInliningNodes = true;
-      if (insideLoop) {
-        maxInliningNodes = InlineWeeder.INLINING_NODES_INSIDE_LOOP +
-            InlineWeeder.INLINING_NODES_INSIDE_LOOP_ARG_FACTOR * numParameters;
-      } else {
-        maxInliningNodes = InlineWeeder.INLINING_NODES_OUTSIDE_LOOP +
-            InlineWeeder.INLINING_NODES_OUTSIDE_LOOP_ARG_FACTOR * numParameters;
-      }
-
-      // If a method is called only once, and all the methods in the
-      // inlining stack are called only once as well, we know we will
-      // save on output size by inlining this method.
-      TypesInferrer inferrer = compiler.typesTask.typesInferrer;
-      if (inferrer.isCalledOnce(element) && allInlinedFunctionsCalledOnce) {
-        useMaxInliningNodes = false;
-      }
-      bool canInline;
-      ast.FunctionExpression functionNode = function.node;
-      canInline = InlineWeeder.canBeInlined(
-          functionNode, maxInliningNodes, useMaxInliningNodes);
-      if (canInline) {
-        backend.inlineCache.markAsInlinable(element, insideLoop: insideLoop);
-      } else {
-        backend.inlineCache.markAsNonInlinable(element, insideLoop: insideLoop);
-      }
-      return canInline;
-    }
-
-    void doInlining() {
-      // Add an explicit null check on the receiver before doing the
-      // inlining. We use [element] to get the same name in the
-      // NoSuchMethodError message as if we had called it.
-      if (element.isInstanceMember
-          && !element.isGenerativeConstructorBody
-          && (selector.mask == null || selector.mask.isNullable)) {
-        addWithPosition(
-            new HFieldGet(null, providedArguments[0], backend.dynamicType,
-                          isAssignable: false),
-            currentNode);
-      }
-      List<HInstruction> compiledArguments = completeSendArgumentsList(
-          function, selector, providedArguments, currentNode);
-      enterInlinedMethod(function, currentNode, compiledArguments);
-      inlinedFrom(function, () {
-        if (!isReachable) {
-          emitReturn(graph.addConstantNull(compiler), null);
-        } else {
-          doInline(function);
-        }
-      });
-      leaveInlinedMethod();
-    }
-
-    if (meetsHardConstraints() && heuristicSayGoodToGo()) {
-      doInlining();
-      registry.registerInlining(
-          element,
-          compiler.currentElement);
-      return true;
-    }
-
-    return false;
-  }
-
-  bool get allInlinedFunctionsCalledOnce {
-    return inliningStack.isEmpty || inliningStack.last.allFunctionsCalledOnce;
-  }
-
-  inlinedFrom(Element element, f()) {
-    assert(element is FunctionElement || element is VariableElement);
-    return compiler.withCurrentElement(element, () {
-      // The [sourceElementStack] contains declaration elements.
-      sourceElementStack.add(element.declaration);
-      var result = f();
-      sourceElementStack.removeLast();
-      return result;
-    });
-  }
-
-  HInstruction handleConstantForOptionalParameter(Element parameter) {
-    ConstantExpression constant =
-        backend.constants.getConstantForVariable(parameter);
-    assert(invariant(parameter, constant != null,
-        message: 'No constant computed for $parameter'));
-    return graph.addConstant(constant.value, compiler);
-  }
-
-  Element get currentNonClosureClass {
-    ClassElement cls = sourceElement.enclosingClass;
-    if (cls != null && cls.isClosure) {
-      var closureClass = cls;
-      return closureClass.methodElement.enclosingClass;
-    } else {
-      return cls;
-    }
-  }
-
-  /**
-   * Returns whether this builder is building code for [element].
-   */
-  bool isBuildingFor(Element element) {
-    return work.element == element;
-  }
-
-  /// A stack of [DartType]s the have been seen during inlining of factory
-  /// constructors.  These types are preserved in [HInvokeStatic]s and
-  /// [HForeignNews] inside the inline code and registered during code
-  /// generation for these nodes.
-  // TODO(karlklose): consider removing this and keeping the (substituted)
-  // types of the type variables in an environment (like the [LocalsHandler]).
-  final List<DartType> currentInlinedInstantiations = <DartType>[];
-
-  final List<AstInliningState> inliningStack = <AstInliningState>[];
-
-  Local returnLocal;
-  DartType returnType;
-
-  bool inTryStatement = false;
-
-  ConstantValue getConstantForNode(ast.Node node) {
-    ConstantExpression constant =
-        backend.constants.getConstantForNode(node, elements);
-    assert(invariant(node, constant != null,
-        message: 'No constant computed for $node'));
-    return constant.value;
-  }
-
-  HInstruction addConstant(ast.Node node) {
-    return graph.addConstant(getConstantForNode(node), compiler);
-  }
-
-  bool isLazilyInitialized(VariableElement element) {
-    ConstantExpression initialValue =
-        backend.constants.getConstantForVariable(element);
-    return initialValue == null;
-  }
-
-  TypeMask cachedTypeOfThis;
-
-  TypeMask getTypeOfThis() {
-    TypeMask result = cachedTypeOfThis;
-    if (result == null) {
-      ThisLocal local = localsHandler.closureData.thisLocal;
-      ClassElement cls = local.enclosingClass;
-      ClassWorld classWorld = compiler.world;
-      if (classWorld.isUsedAsMixin(cls)) {
-        // If the enclosing class is used as a mixin, [:this:] can be
-        // of the class that mixins the enclosing class. These two
-        // classes do not have a subclass relationship, so, for
-        // simplicity, we mark the type as an interface type.
-        result = new TypeMask.nonNullSubtype(cls.declaration, compiler.world);
-      } else {
-        result = new TypeMask.nonNullSubclass(cls.declaration, compiler.world);
-      }
-      cachedTypeOfThis = result;
-    }
-    return result;
-  }
-
-  Map<Element, TypeMask> cachedTypesOfCapturedVariables =
-      new Map<Element, TypeMask>();
-
-  TypeMask getTypeOfCapturedVariable(Element element) {
-    assert(element.isField);
-    return cachedTypesOfCapturedVariables.putIfAbsent(element, () {
-      return TypeMaskFactory.inferredTypeForElement(element, compiler);
-    });
-  }
-
-  /**
-   * Documentation wanted -- johnniwinther
-   *
-   * Invariant: [functionElement] must be an implementation element.
-   */
-  HGraph buildMethod(FunctionElement functionElement) {
-    assert(invariant(functionElement, functionElement.isImplementation));
-    graph.calledInLoop = compiler.world.isCalledInLoop(functionElement);
-    ast.FunctionExpression function = functionElement.node;
-    assert(function != null);
-    assert(!function.modifiers.isExternal);
-    assert(elements.getFunctionDefinition(function) != null);
-    openFunction(functionElement, function);
-    String name = functionElement.name;
-    // If [functionElement] is `operator==` we explicitely add a null check at
-    // the beginning of the method. This is to avoid having call sites do the
-    // null check.
-    if (name == '==') {
-      if (!backend.operatorEqHandlesNullArgument(functionElement)) {
-        handleIf(
-            function,
-            () {
-              HParameterValue parameter = parameters.values.first;
-              push(new HIdentity(
-                  parameter, graph.addConstantNull(compiler), null,
-                  backend.boolType));
-            },
-            () {
-              closeAndGotoExit(new HReturn(
-                  graph.addConstantBool(false, compiler)));
-            },
-            null);
-      }
-    }
-    function.body.accept(this);
-    return closeFunction();
-  }
-
-  HGraph buildCheckedSetter(VariableElement field) {
-    openFunction(field, field.node);
-    HInstruction thisInstruction = localsHandler.readThis();
-    // Use dynamic type because the type computed by the inferrer is
-    // narrowed to the type annotation.
-    HInstruction parameter = new HParameterValue(field, backend.dynamicType);
-    // Add the parameter as the last instruction of the entry block.
-    // If the method is intercepted, we want the actual receiver
-    // to be the first parameter.
-    graph.entry.addBefore(graph.entry.last, parameter);
-    HInstruction value =
-        potentiallyCheckType(parameter, field.type);
-    add(new HFieldSet(field, thisInstruction, value));
-    return closeFunction();
-  }
-
-  HGraph buildLazyInitializer(VariableElement variable) {
-    ast.Node node = variable.node;
-    openFunction(variable, node);
-    assert(variable.initializer != null);
-    visit(variable.initializer);
-    HInstruction value = pop();
-    value = potentiallyCheckType(value, variable.type);
-    closeAndGotoExit(new HReturn(value));
-    return closeFunction();
-  }
-
-  /**
-   * Returns the constructor body associated with the given constructor or
-   * creates a new constructor body, if none can be found.
-   *
-   * Returns [:null:] if the constructor does not have a body.
-   */
-  ConstructorBodyElement getConstructorBody(FunctionElement constructor) {
-    assert(constructor.isGenerativeConstructor);
-    assert(invariant(constructor, constructor.isImplementation));
-    if (constructor.isSynthesized) return null;
-    ast.FunctionExpression node = constructor.node;
-    // If we know the body doesn't have any code, we don't generate it.
-    if (!node.hasBody()) return null;
-    if (node.hasEmptyBody()) return null;
-    ClassElement classElement = constructor.enclosingClass;
-    ConstructorBodyElement bodyElement;
-    classElement.forEachBackendMember((Element backendMember) {
-      if (backendMember.isGenerativeConstructorBody) {
-        ConstructorBodyElement body = backendMember;
-        if (body.constructor == constructor) {
-          // TODO(kasperl): Find a way of stopping the iteration
-          // through the backend members.
-          bodyElement = backendMember;
-        }
-      }
-    });
-    if (bodyElement == null) {
-      bodyElement = new ConstructorBodyElementX(constructor);
-      classElement.addBackendMember(bodyElement);
-
-      if (constructor.isPatch) {
-        // Create origin body element for patched constructors.
-        ConstructorBodyElementX patch = bodyElement;
-        ConstructorBodyElementX origin =
-            new ConstructorBodyElementX(constructor.origin);
-        origin.applyPatch(patch);
-        classElement.origin.addBackendMember(bodyElement.origin);
-      }
-    }
-    assert(bodyElement.isGenerativeConstructorBody);
-    return bodyElement;
-  }
-
-  HParameterValue addParameter(Entity parameter, TypeMask type) {
-    assert(inliningStack.isEmpty);
-    HParameterValue result = new HParameterValue(parameter, type);
-    if (lastAddedParameter == null) {
-      graph.entry.addBefore(graph.entry.first, result);
-    } else {
-      graph.entry.addAfter(lastAddedParameter, result);
-    }
-    lastAddedParameter = result;
-    return result;
-  }
-
-  /**
-   * This method sets up the local state of the builder for inlining [function].
-   * The arguments of the function are inserted into the [localsHandler].
-   *
-   * When inlining a function, [:return:] statements are not emitted as
-   * [HReturn] instructions. Instead, the value of a synthetic element is
-   * updated in the [localsHandler]. This function creates such an element and
-   * stores it in the [returnLocal] field.
-   */
-  void setupStateForInlining(FunctionElement function,
-                             List<HInstruction> compiledArguments) {
-    localsHandler = new LocalsHandler(this, function);
-    localsHandler.closureData =
-        compiler.closureToClassMapper.computeClosureToClassMapping(
-            function, function.node, elements);
-    returnLocal = new SyntheticLocal("result", function);
-    localsHandler.updateLocal(returnLocal,
-        graph.addConstantNull(compiler));
-
-    inTryStatement = false; // TODO(lry): why? Document.
-
-    int argumentIndex = 0;
-    if (function.isInstanceMember) {
-      localsHandler.updateLocal(localsHandler.closureData.thisLocal,
-          compiledArguments[argumentIndex++]);
-    }
-
-    FunctionSignature signature = function.functionSignature;
-    signature.orderedForEachParameter((ParameterElement parameter) {
-      HInstruction argument = compiledArguments[argumentIndex++];
-      localsHandler.updateLocal(parameter, argument);
-    });
-
-    ClassElement enclosing = function.enclosingClass;
-    if ((function.isConstructor || function.isGenerativeConstructorBody)
-        && backend.classNeedsRti(enclosing)) {
-      enclosing.typeVariables.forEach((TypeVariableType typeVariable) {
-        HInstruction argument = compiledArguments[argumentIndex++];
-        localsHandler.updateLocal(
-            localsHandler.getTypeVariableAsLocal(typeVariable), argument);
-      });
-    }
-    assert(argumentIndex == compiledArguments.length);
-
-    elements = function.resolvedAst.elements;
-    assert(elements != null);
-    returnType = signature.type.returnType;
-    stack = <HInstruction>[];
-
-    insertTraceCall(function);
-  }
-
-  void restoreState(AstInliningState state) {
-    localsHandler = state.oldLocalsHandler;
-    returnLocal = state.oldReturnLocal;
-    inTryStatement = state.inTryStatement;
-    elements = state.oldElements;
-    returnType = state.oldReturnType;
-    assert(stack.isEmpty);
-    stack = state.oldStack;
-  }
-
-  /**
-   * Run this builder on the body of the [function] to be inlined.
-   */
-  void visitInlinedFunction(FunctionElement function) {
-    potentiallyCheckInlinedParameterTypes(function);
-    if (function.isGenerativeConstructor) {
-      buildFactory(function);
-    } else {
-      ast.FunctionExpression functionNode = function.node;
-      functionNode.body.accept(this);
-    }
-  }
-
-
-  addInlinedInstantiation(DartType type) {
-    if (type != null) {
-      currentInlinedInstantiations.add(type);
-    }
-  }
-
-  removeInlinedInstantiation(DartType type) {
-    if (type != null) {
-      currentInlinedInstantiations.removeLast();
-    }
-  }
-
-  bool providedArgumentsKnownToBeComplete(ast.Node currentNode) {
-    /* When inlining the iterator methods generated for a [:for-in:] loop, the
-     * [currentNode] is the [ForIn] tree. The compiler-generated iterator
-     * invocations are known to have fully specified argument lists, no default
-     * arguments are used. See invocations of [pushInvokeDynamic] in
-     * [visitForIn].
-     */
-    return currentNode.asForIn() != null;
-  }
-
-  /**
-   * In checked mode, generate type tests for the parameters of the inlined
-   * function.
-   */
-  void potentiallyCheckInlinedParameterTypes(FunctionElement function) {
-    if (!compiler.enableTypeAssertions) return;
-
-    FunctionSignature signature = function.functionSignature;
-    signature.orderedForEachParameter((ParameterElement parameter) {
-      HInstruction argument = localsHandler.readLocal(parameter);
-      potentiallyCheckType(argument, parameter.type);
-    });
-  }
-
-  /**
-   * Documentation wanted -- johnniwinther
-   *
-   * Invariant: [constructors] must contain only implementation elements.
-   */
-  void inlineSuperOrRedirect(FunctionElement callee,
-                             List<HInstruction> compiledArguments,
-                             List<FunctionElement> constructors,
-                             Map<Element, HInstruction> fieldValues,
-                             FunctionElement caller) {
-    callee = callee.implementation;
-    compiler.withCurrentElement(callee, () {
-      constructors.add(callee);
-      ClassElement enclosingClass = callee.enclosingClass;
-      if (backend.classNeedsRti(enclosingClass)) {
-        // If [enclosingClass] needs RTI, we have to give a value to its
-        // type parameters.
-        ClassElement currentClass = caller.enclosingClass;
-        // For a super constructor call, the type is the supertype of
-        // [currentClass]. For a redirecting constructor, the type is
-        // the current type. [InterfaceType.asInstanceOf] takes care
-        // of both.
-        InterfaceType type = currentClass.thisType.asInstanceOf(enclosingClass);
-        type = localsHandler.substInContext(type);
-        List<DartType> arguments = type.typeArguments;
-        List<DartType> typeVariables = enclosingClass.typeVariables;
-        if (!type.isRaw) {
-          assert(arguments.length == typeVariables.length);
-          Iterator<DartType> variables = typeVariables.iterator;
-          type.typeArguments.forEach((DartType argument) {
-            variables.moveNext();
-            TypeVariableType typeVariable = variables.current;
-            localsHandler.updateLocal(
-                localsHandler.getTypeVariableAsLocal(typeVariable),
-                analyzeTypeArgument(argument));
-          });
-        } else {
-          // If the supertype is a raw type, we need to set to null the
-          // type variables.
-          for (TypeVariableType variable in typeVariables) {
-            localsHandler.updateLocal(
-                localsHandler.getTypeVariableAsLocal(variable),
-                graph.addConstantNull(compiler));
-          }
-        }
-      }
-
-      // For redirecting constructors, the fields have already been
-      // initialized by the caller.
-      if (callee.enclosingClass != caller.enclosingClass) {
-        inlinedFrom(callee, () {
-          buildFieldInitializers(callee.enclosingElement.implementation,
-                               fieldValues);
-        });
-      }
-
-      int index = 0;
-      FunctionSignature params = callee.functionSignature;
-      params.orderedForEachParameter((ParameterElement parameter) {
-        HInstruction argument = compiledArguments[index++];
-        // Because we are inlining the initializer, we must update
-        // what was given as parameter. This will be used in case
-        // there is a parameter check expression in the initializer.
-        parameters[parameter] = argument;
-        localsHandler.updateLocal(parameter, argument);
-        // Don't forget to update the field, if the parameter is of the
-        // form [:this.x:].
-        if (parameter.isInitializingFormal) {
-          InitializingFormalElement fieldParameterElement = parameter;
-          fieldValues[fieldParameterElement.fieldElement] = argument;
-        }
-      });
-
-      // Build the initializers in the context of the new constructor.
-      TreeElements oldElements = elements;
-      ResolvedAst resolvedAst = callee.resolvedAst;
-      elements = resolvedAst.elements;
-      ClosureClassMap oldClosureData = localsHandler.closureData;
-      ast.Node node = resolvedAst.node;
-      ClosureClassMap newClosureData =
-          compiler.closureToClassMapper.computeClosureToClassMapping(
-              callee, node, elements);
-      localsHandler.closureData = newClosureData;
-      localsHandler.enterScope(node, callee);
-      buildInitializers(callee, constructors, fieldValues);
-      localsHandler.closureData = oldClosureData;
-      elements = oldElements;
-    });
-  }
-
-  /**
-   * Run through the initializers and inline all field initializers. Recursively
-   * inlines super initializers.
-   *
-   * The constructors of the inlined initializers is added to [constructors]
-   * with sub constructors having a lower index than super constructors.
-   *
-   * Invariant: The [constructor] and elements in [constructors] must all be
-   * implementation elements.
-   */
-  void buildInitializers(ConstructorElement constructor,
-                         List<FunctionElement> constructors,
-                         Map<Element, HInstruction> fieldValues) {
-    assert(invariant(constructor, constructor.isImplementation));
-    if (constructor.isSynthesized) {
-      List<HInstruction> arguments = <HInstruction>[];
-      HInstruction compileArgument(ParameterElement parameter) {
-        return localsHandler.readLocal(parameter);
-      }
-
-      Element target = constructor.definingConstructor.implementation;
-      bool match = Selector.addForwardingElementArgumentsToList(
-          constructor,
-          arguments,
-          target,
-          compileArgument,
-          handleConstantForOptionalParameter,
-          compiler.world);
-      if (!match) {
-        // If this fails, the selector we constructed for the call to a
-        // forwarding constructor in a mixin application did not match the
-        // constructor (which, for example, may happen when the libraries are
-        // not compatible for private names, see issue 20394).
-        compiler.internalError(constructor,
-                               'forwarding constructor call does not match');
-      }
-      inlineSuperOrRedirect(
-          target,
-          arguments,
-          constructors,
-          fieldValues,
-          constructor);
-      return;
-    }
-    ast.FunctionExpression functionNode = constructor.node;
-
-    bool foundSuperOrRedirect = false;
-    if (functionNode.initializers != null) {
-      Link<ast.Node> initializers = functionNode.initializers.nodes;
-      for (Link<ast.Node> link = initializers; !link.isEmpty; link = link.tail) {
-        assert(link.head is ast.Send);
-        if (link.head is !ast.SendSet) {
-          // A super initializer or constructor redirection.
-          foundSuperOrRedirect = true;
-          ast.Send call = link.head;
-          assert(ast.Initializers.isSuperConstructorCall(call) ||
-                 ast.Initializers.isConstructorRedirect(call));
-          FunctionElement target = elements[call].implementation;
-          Selector selector = elements.getSelector(call);
-          Link<ast.Node> arguments = call.arguments;
-          List<HInstruction> compiledArguments = new List<HInstruction>();
-          inlinedFrom(constructor, () {
-            addStaticSendArgumentsToList(selector,
-                                         arguments,
-                                         target,
-                                         compiledArguments);
-          });
-          inlineSuperOrRedirect(target,
-                                compiledArguments,
-                                constructors,
-                                fieldValues,
-                                constructor);
-        } else {
-          // A field initializer.
-          ast.SendSet init = link.head;
-          Link<ast.Node> arguments = init.arguments;
-          assert(!arguments.isEmpty && arguments.tail.isEmpty);
-          inlinedFrom(constructor, () {
-            visit(arguments.head);
-          });
-          fieldValues[elements[init]] = pop();
-        }
-      }
-    }
-
-    if (!foundSuperOrRedirect) {
-      // No super initializer found. Try to find the default constructor if
-      // the class is not Object.
-      ClassElement enclosingClass = constructor.enclosingClass;
-      ClassElement superClass = enclosingClass.superclass;
-      if (!enclosingClass.isObject) {
-        assert(superClass != null);
-        assert(superClass.resolutionState == STATE_DONE);
-        Selector selector =
-            new Selector.callDefaultConstructor(enclosingClass.library);
-        // TODO(johnniwinther): Should we find injected constructors as well?
-        FunctionElement target = superClass.lookupConstructor(selector);
-        if (target == null) {
-          compiler.internalError(superClass,
-              "No default constructor available.");
-        }
-        List<HInstruction> arguments = <HInstruction>[];
-        selector.addArgumentsToList(const Link<ast.Node>(),
-                                    arguments,
-                                    target.implementation,
-                                    null,
-                                    handleConstantForOptionalParameter,
-                                    compiler.world);
-        inlineSuperOrRedirect(target,
-                              arguments,
-                              constructors,
-                              fieldValues,
-                              constructor);
-      }
-    }
-  }
-
-  /**
-   * Run through the fields of [cls] and add their potential
-   * initializers.
-   *
-   * Invariant: [classElement] must be an implementation element.
-   */
-  void buildFieldInitializers(ClassElement classElement,
-                              Map<Element, HInstruction> fieldValues) {
-    assert(invariant(classElement, classElement.isImplementation));
-    classElement.forEachInstanceField(
-        (ClassElement enclosingClass, VariableElement member) {
-          compiler.withCurrentElement(member, () {
-            TreeElements definitions = member.treeElements;
-            ast.Node node = member.node;
-            ast.Expression initializer = member.initializer;
-            if (initializer == null) {
-              // Unassigned fields of native classes are not initialized to
-              // prevent overwriting pre-initialized native properties.
-              if (!Elements.isNativeOrExtendsNative(classElement)) {
-                fieldValues[member] = graph.addConstantNull(compiler);
-              }
-            } else {
-              ast.Node right = initializer;
-              TreeElements savedElements = elements;
-              elements = definitions;
-              // In case the field initializer uses closures, run the
-              // closure to class mapper.
-              compiler.closureToClassMapper.computeClosureToClassMapping(
-                  member, node, elements);
-              inlinedFrom(member, () => right.accept(this));
-              elements = savedElements;
-              fieldValues[member] = pop();
-            }
-          });
-        });
-  }
-
-  /**
-   * Build the factory function corresponding to the constructor
-   * [functionElement]:
-   *  - Initialize fields with the values of the field initializers of the
-   *    current constructor and super constructors or constructors redirected
-   *    to, starting from the current constructor.
-   *  - Call the constructor bodies, starting from the constructor(s) in the
-   *    super class(es).
-   */
-  HGraph buildFactory(FunctionElement functionElement) {
-    functionElement = functionElement.implementation;
-    ClassElement classElement =
-        functionElement.enclosingClass.implementation;
-    bool isNativeUpgradeFactory =
-        Elements.isNativeOrExtendsNative(classElement);
-    ast.FunctionExpression function = functionElement.node;
-    // Note that constructors (like any other static function) do not need
-    // to deal with optional arguments. It is the callers job to provide all
-    // arguments as if they were positional.
-
-    if (inliningStack.isEmpty) {
-      // The initializer list could contain closures.
-      openFunction(functionElement, function);
-    }
-
-    Map<Element, HInstruction> fieldValues = new Map<Element, HInstruction>();
-
-    // Compile the possible initialization code for local fields and
-    // super fields.
-    buildFieldInitializers(classElement, fieldValues);
-
-    // Compile field-parameters such as [:this.x:].
-    FunctionSignature params = functionElement.functionSignature;
-    params.orderedForEachParameter((ParameterElement parameter) {
-      if (parameter.isInitializingFormal) {
-        // If the [element] is a field-parameter then
-        // initialize the field element with its value.
-        InitializingFormalElement fieldParameter = parameter;
-        HInstruction parameterValue =
-            localsHandler.readLocal(fieldParameter);
-        fieldValues[fieldParameter.fieldElement] = parameterValue;
-      }
-    });
-
-    // Analyze the constructor and all referenced constructors and collect
-    // initializers and constructor bodies.
-    List<FunctionElement> constructors = <FunctionElement>[functionElement];
-    buildInitializers(functionElement, constructors, fieldValues);
-
-    // Call the JavaScript constructor with the fields as argument.
-    List<HInstruction> constructorArguments = <HInstruction>[];
-    List<Element> fields = <Element>[];
-
-    classElement.forEachInstanceField(
-        (ClassElement enclosingClass, VariableElement member) {
-          HInstruction value = fieldValues[member];
-          if (value == null) {
-            // Uninitialized native fields are pre-initialized by the native
-            // implementation.
-            assert(isNativeUpgradeFactory);
-          } else {
-            fields.add(member);
-            DartType type = localsHandler.substInContext(member.type);
-            constructorArguments.add(potentiallyCheckType(value, type));
-          }
-        },
-        includeSuperAndInjectedMembers: true);
-
-    InterfaceType type = classElement.thisType;
-    TypeMask ssaType =
-        new TypeMask.nonNullExact(classElement.declaration, compiler.world);
-    List<DartType> instantiatedTypes;
-    addInlinedInstantiation(type);
-    if (!currentInlinedInstantiations.isEmpty) {
-      instantiatedTypes = new List<DartType>.from(currentInlinedInstantiations);
-    }
-
-    HInstruction newObject;
-    if (!isNativeUpgradeFactory) {
-      newObject = new HForeignNew(classElement,
-          ssaType,
-          constructorArguments,
-          instantiatedTypes);
-      add(newObject);
-    } else {
-      // Bulk assign to the initialized fields.
-      newObject = graph.explicitReceiverParameter;
-      // Null guard ensures an error if we are being called from an explicit
-      // 'new' of the constructor instead of via an upgrade. It is optimized out
-      // if there are field initializers.
-      add(new HFieldGet(
-          null, newObject, backend.dynamicType, isAssignable: false));
-      for (int i = 0; i < fields.length; i++) {
-        add(new HFieldSet(fields[i], newObject, constructorArguments[i]));
-      }
-    }
-    removeInlinedInstantiation(type);
-    // Create the runtime type information, if needed.
-    if (backend.classNeedsRti(classElement)) {
-      // Read the values of the type arguments and create a list to set on the
-      // newly create object.  We can identify the case where the new list
-      // would be of the form:
-      //  [getTypeArgumentByIndex(this, 0), .., getTypeArgumentByIndex(this, k)]
-      // and k is the number of type arguments of this.  If this is the case,
-      // we can simply copy the list from this.
-
-      // These locals are modified by [isIndexedTypeArgumentGet].
-      HThis source;  // The source of the type arguments.
-      bool allIndexed = true;
-      int expectedIndex = 0;
-      ClassElement contextClass;  // The class of `this`.
-      int remainingTypeVariables;  // The number of 'remaining type variables'
-                                   // of `this`.
-
-      /// Helper to identify instructions that read a type variable without
-      /// substitution (that is, directly use the index). These instructions
-      /// are of the form:
-      ///   HInvokeStatic(getTypeArgumentByIndex, this, index)
-      ///
-      /// Return `true` if [instruction] is of that form and the index is the
-      /// next index in the sequence (held in [expectedIndex]).
-      bool isIndexedTypeArgumentGet(HInstruction instruction) {
-        if (instruction is! HInvokeStatic) return false;
-        HInvokeStatic invoke = instruction;
-        if (invoke.element != backend.getGetTypeArgumentByIndex()) {
-          return false;
-        }
-        HConstant index = invoke.inputs[1];
-        HInstruction newSource = invoke.inputs[0];
-        if (newSource is! HThis) {
-          return false;
-        }
-        if (source == null) {
-          // This is the first match. Extract the context class for the type
-          // variables and get the list of type variables to keep track of how
-          // many arguments we need to process.
-          source = newSource;
-          contextClass = source.sourceElement.enclosingClass;
-          remainingTypeVariables = contextClass.typeVariables.length;
-        } else {
-          assert(source == newSource);
-        }
-        // If there are no more type variables, then there are more type
-        // arguments for the new object than the source has, and it can't be
-        // a copy.  Otherwise remove one argument.
-        if (remainingTypeVariables == 0) return false;
-        remainingTypeVariables--;
-        // Check that the index is the one we expect.
-        IntConstantValue constant = index.constant;
-        return constant.primitiveValue == expectedIndex++;
-      }
-
-      List<HInstruction> typeArguments = <HInstruction>[];
-      classElement.typeVariables.forEach((TypeVariableType typeVariable) {
-        HInstruction argument = localsHandler.readLocal(
-            localsHandler.getTypeVariableAsLocal(typeVariable));
-        if (allIndexed && !isIndexedTypeArgumentGet(argument)) {
-          allIndexed = false;
-        }
-        typeArguments.add(argument);
-      });
-
-      if (source != null && allIndexed && remainingTypeVariables == 0) {
-        copyRuntimeTypeInfo(source, newObject);
-      } else {
-        newObject =
-            callSetRuntimeTypeInfo(classElement, typeArguments, newObject);
-      }
-    }
-
-    // Generate calls to the constructor bodies.
-    HInstruction interceptor = null;
-    for (int index = constructors.length - 1; index >= 0; index--) {
-      FunctionElement constructor = constructors[index];
-      assert(invariant(functionElement, constructor.isImplementation));
-      ConstructorBodyElement body = getConstructorBody(constructor);
-      if (body == null) continue;
-
-      List bodyCallInputs = <HInstruction>[];
-      if (isNativeUpgradeFactory) {
-        if (interceptor == null) {
-          ConstantValue constant =
-              new InterceptorConstantValue(classElement.thisType);
-          interceptor = graph.addConstant(constant, compiler);
-        }
-        bodyCallInputs.add(interceptor);
-      }
-      bodyCallInputs.add(newObject);
-      ResolvedAst resolvedAst = constructor.resolvedAst;
-      TreeElements elements = resolvedAst.elements;
-      ast.Node node = resolvedAst.node;
-      ClosureClassMap parameterClosureData =
-          compiler.closureToClassMapper.getMappingForNestedFunction(node);
-
-      FunctionSignature functionSignature = body.functionSignature;
-      // Provide the parameters to the generative constructor body.
-      functionSignature.orderedForEachParameter((ParameterElement parameter) {
-        // If [parameter] is boxed, it will be a field in the box passed as the
-        // last parameter. So no need to directly pass it.
-        if (!localsHandler.isBoxed(parameter)) {
-          bodyCallInputs.add(localsHandler.readLocal(parameter));
-        }
-      });
-
-      ClassElement currentClass = constructor.enclosingClass;
-      if (backend.classNeedsRti(currentClass)) {
-        // If [currentClass] needs RTI, we add the type variables as
-        // parameters of the generative constructor body.
-        currentClass.typeVariables.forEach((TypeVariableType argument) {
-          // TODO(johnniwinther): Substitute [argument] with
-          // `localsHandler.substInContext(argument)`.
-          bodyCallInputs.add(localsHandler.readLocal(
-              localsHandler.getTypeVariableAsLocal(argument)));
-        });
-      }
-
-      // If there are locals that escape (ie mutated in closures), we
-      // pass the box to the constructor.
-      ClosureScope scopeData = parameterClosureData.capturingScopes[node];
-      if (scopeData != null) {
-        bodyCallInputs.add(localsHandler.readLocal(scopeData.boxElement));
-      }
-
-      if (!isNativeUpgradeFactory && // TODO(13836): Fix inlining.
-          tryInlineMethod(body, null, bodyCallInputs, function)) {
-        pop();
-      } else {
-        HInvokeConstructorBody invoke = new HInvokeConstructorBody(
-            body.declaration, bodyCallInputs, backend.nonNullType);
-        invoke.sideEffects =
-            compiler.world.getSideEffectsOfElement(constructor);
-        add(invoke);
-      }
-    }
-    if (inliningStack.isEmpty) {
-      closeAndGotoExit(new HReturn(newObject));
-      return closeFunction();
-    } else {
-      localsHandler.updateLocal(returnLocal, newObject);
-      return null;
-    }
-  }
-
-  /**
-   * Documentation wanted -- johnniwinther
-   *
-   * Invariant: [functionElement] must be the implementation element.
-   */
-  void openFunction(Element element, ast.Node node) {
-    assert(invariant(element, element.isImplementation));
-    HBasicBlock block = graph.addNewBlock();
-    open(graph.entry);
-
-    localsHandler.startFunction(element, node);
-    close(new HGoto()).addSuccessor(block);
-
-    open(block);
-
-    // Add the type parameters of the class as parameters of this method.  This
-    // must be done before adding the normal parameters, because their types
-    // may contain references to type variables.
-    var enclosing = element.enclosingElement;
-    if ((element.isConstructor || element.isGenerativeConstructorBody)
-        && backend.classNeedsRti(enclosing)) {
-      enclosing.typeVariables.forEach((TypeVariableType typeVariable) {
-        HParameterValue param = addParameter(
-            typeVariable.element, backend.nonNullType);
-        localsHandler.directLocals[
-            localsHandler.getTypeVariableAsLocal(typeVariable)] = param;
-      });
-    }
-
-    if (element is FunctionElement) {
-      FunctionElement functionElement = element;
-      FunctionSignature signature = functionElement.functionSignature;
-
-      // Put the type checks in the first successor of the entry,
-      // because that is where the type guards will also be inserted.
-      // This way we ensure that a type guard will dominate the type
-      // check.
-      ClosureScope scopeData =
-          localsHandler.closureData.capturingScopes[node];
-      signature.orderedForEachParameter((ParameterElement parameterElement) {
-        if (element.isGenerativeConstructorBody) {
-          if (scopeData != null &&
-              scopeData.isCapturedVariable(parameterElement)) {
-            // The parameter will be a field in the box passed as the
-            // last parameter. So no need to have it.
-            return;
-          }
-        }
-        HInstruction newParameter =
-            localsHandler.directLocals[parameterElement];
-        if (!element.isConstructor ||
-            !(element as ConstructorElement).isRedirectingFactory) {
-          // Redirection factories must not check their argument types.
-          // Example:
-          //
-          //     class A {
-          //       A(String foo) = A.b;
-          //       A(int foo) { print(foo); }
-          //     }
-          //     main() {
-          //       new A(499);    // valid even in checked mode.
-          //       new A("foo");  // invalid in checked mode.
-          //
-          // Only the final target is allowed to check for the argument types.
-          newParameter =
-              potentiallyCheckType(newParameter, parameterElement.type);
-        }
-        localsHandler.directLocals[parameterElement] = newParameter;
-      });
-
-      returnType = signature.type.returnType;
-    } else {
-      // Otherwise it is a lazy initializer which does not have parameters.
-      assert(element is VariableElement);
-    }
-
-    insertTraceCall(element);
-  }
-
-  insertTraceCall(Element element) {
-    if (JavaScriptBackend.TRACE_CALLS) {
-      if (element == backend.traceHelper) return;
-      n(e) => e == null ? '' : e.name;
-      String name = "${n(element.library)}:${n(element.enclosingClass)}."
-        "${n(element)}";
-      HConstant nameConstant = addConstantString(name);
-      add(new HInvokeStatic(backend.traceHelper,
-                            <HInstruction>[nameConstant],
-                            backend.dynamicType));
-    }
-  }
-
-  /// Check that [type] is valid in the context of `localsHandler.contextClass`.
-  /// This should only be called in assertions.
-  bool assertTypeInContext(DartType type, [Spannable spannable]) {
-    return invariant(spannable == null ? CURRENT_ELEMENT_SPANNABLE : spannable,
-        () {
-          ClassElement contextClass = Types.getClassContext(type);
-          return contextClass == null ||
-                 contextClass == localsHandler.contextClass;
-        },
-        message: "Type '$type' is not valid context of "
-                 "${localsHandler.contextClass}.");
-  }
-
-  /// Build a [HTypeConversion] for convertion [original] to type [type].
-  ///
-  /// Invariant: [type] must be valid in the context.
-  /// See [LocalsHandler.substInContext].
-  HInstruction buildTypeConversion(HInstruction original,
-                                   DartType type,
-                                   int kind) {
-    if (type == null) return original;
-    type = type.unalias(compiler);
-    assert(assertTypeInContext(type, original));
-    if (type.isInterfaceType && !type.treatAsRaw) {
-      TypeMask subtype = new TypeMask.subtype(type.element, compiler.world);
-      HInstruction representations = buildTypeArgumentRepresentations(type);
-      add(representations);
-      return new HTypeConversion.withTypeRepresentation(type, kind, subtype,
-          original, representations);
-    } else if (type.isTypeVariable) {
-      TypeMask subtype = original.instructionType;
-      HInstruction typeVariable = addTypeVariableReference(type);
-      return new HTypeConversion.withTypeRepresentation(type, kind, subtype,
-          original, typeVariable);
-    } else if (type.isFunctionType) {
-      String name = kind == HTypeConversion.CAST_TYPE_CHECK
-          ? '_asCheck' : '_assertCheck';
-
-      List arguments = [buildFunctionType(type), original];
-      pushInvokeDynamic(
-          null,
-          new Selector.call(name, backend.jsHelperLibrary, 1),
-          arguments);
-
-      return new HTypeConversion(type, kind, original.instructionType, pop());
-    } else {
-      return original.convertType(compiler, type, kind);
-    }
-  }
-
-  HInstruction potentiallyBuildTypeHint(HInstruction original, DartType type) {
-    if (!compiler.trustTypeAnnotations || type == null) return original;
-    type = localsHandler.substInContext(type);
-    if (!type.isInterfaceType) return original;
-    TypeMask mask = new TypeMask.subtype(type.element, compiler.world);
-    var result = new HTypeKnown.pinned(mask, original);
-    return result;
-  }
-
-  HInstruction potentiallyCheckType(HInstruction original, DartType type,
-      { int kind: HTypeConversion.CHECKED_MODE_CHECK }) {
-    if (!compiler.enableTypeAssertions) return original;
-    type = localsHandler.substInContext(type);
-    HInstruction other = buildTypeConversion(original, type, kind);
-    if (other != original) add(other);
-    registry.registerIsCheck(type);
-    return other;
-  }
-
-  void assertIsSubtype(ast.Node node, DartType subtype, DartType supertype,
-                       String message) {
-    HInstruction subtypeInstruction =
-        analyzeTypeArgument(localsHandler.substInContext(subtype));
-    HInstruction supertypeInstruction =
-        analyzeTypeArgument(localsHandler.substInContext(supertype));
-    HInstruction messageInstruction =
-        graph.addConstantString(new ast.DartString.literal(message), compiler);
-    Element element = backend.getAssertIsSubtype();
-    var inputs = <HInstruction>[subtypeInstruction, supertypeInstruction,
-                                messageInstruction];
-    HInstruction assertIsSubtype = new HInvokeStatic(
-        element, inputs, subtypeInstruction.instructionType);
-    registry.registerTypeVariableBoundsSubtypeCheck(subtype, supertype);
-    add(assertIsSubtype);
-  }
-
-  HGraph closeFunction() {
-    // TODO(kasperl): Make this goto an implicit return.
-    if (!isAborted()) closeAndGotoExit(new HGoto());
-    graph.finalize();
-    return graph;
-  }
-
-  void push(HInstruction instruction) {
-    add(instruction);
-    stack.add(instruction);
-  }
-
-  void pushWithPosition(HInstruction instruction, ast.Node node) {
-    push(attachPosition(instruction, node));
-  }
-
-  HInstruction pop() {
-    return stack.removeLast();
-  }
-
-  void dup() {
-    stack.add(stack.last);
-  }
-
-  HInstruction popBoolified() {
-    HInstruction value = pop();
-    if (compiler.enableTypeAssertions) {
-      return potentiallyCheckType(
-          value,
-          compiler.boolClass.rawType,
-          kind: HTypeConversion.BOOLEAN_CONVERSION_CHECK);
-    }
-    HInstruction result = new HBoolify(value, backend.boolType);
-    add(result);
-    return result;
-  }
-
-  HInstruction attachPosition(HInstruction target, ast.Node node) {
-    if (node != null) {
-      target.sourcePosition = sourceFileLocationForBeginToken(node);
-    }
-    return target;
-  }
-
-  SourceFileLocation sourceFileLocationForBeginToken(ast.Node node) =>
-      sourceFileLocationForToken(node, node.getBeginToken());
-
-  SourceFileLocation sourceFileLocationForEndToken(ast.Node node) =>
-      sourceFileLocationForToken(node, node.getEndToken());
-
-  SourceFileLocation sourceFileLocationForToken(ast.Node node, Token token) {
-    SourceFile sourceFile = currentSourceFile();
-    SourceFileLocation location =
-        new TokenSourceFileLocation(sourceFile, token, sourceElement.name);
-    checkValidSourceFileLocation(location, sourceFile, token.charOffset);
-    return location;
-  }
-
-  void visit(ast.Node node) {
-    if (node != null) node.accept(this);
-  }
-
-  visitBlock(ast.Block node) {
-    assert(!isAborted());
-    if (!isReachable) return;  // This can only happen when inlining.
-    for (Link<ast.Node> link = node.statements.nodes;
-         !link.isEmpty;
-         link = link.tail) {
-      visit(link.head);
-      if (!isReachable) {
-        // The block has been aborted by a return or a throw.
-        if (!stack.isEmpty) {
-          compiler.internalError(node, 'Non-empty instruction stack.');
-        }
-        return;
-      }
-    }
-    assert(!current.isClosed());
-    if (!stack.isEmpty) {
-      compiler.internalError(node, 'Non-empty instruction stack.');
-    }
-  }
-
-  visitClassNode(ast.ClassNode node) {
-    compiler.internalError(node,
-        'SsaBuilder.visitClassNode should not be called.');
-  }
-
-  visitThrowExpression(ast.Expression expression) {
-    bool old = inExpressionOfThrow;
-    try {
-      inExpressionOfThrow = true;
-      visit(expression);
-    } finally {
-      inExpressionOfThrow = old;
-    }
-  }
-
-  visitExpressionStatement(ast.ExpressionStatement node) {
-    if (!isReachable) return;
-    ast.Throw throwExpression = node.expression.asThrow();
-    if (throwExpression != null && inliningStack.isEmpty) {
-      visitThrowExpression(throwExpression.expression);
-      handleInTryStatement();
-      closeAndGotoExit(new HThrow(pop()));
-    } else {
-      visit(node.expression);
-      pop();
-    }
-  }
-
-  /**
-   * Creates a new loop-header block. The previous [current] block
-   * is closed with an [HGoto] and replaced by the newly created block.
-   * Also notifies the locals handler that we're entering a loop.
-   */
-  JumpHandler beginLoopHeader(ast.Node node) {
-    assert(!isAborted());
-    HBasicBlock previousBlock = close(new HGoto());
-
-    JumpHandler jumpHandler = createJumpHandler(node, isLoopJump: true);
-    HBasicBlock loopEntry = graph.addNewLoopHeaderBlock(
-        jumpHandler.target,
-        jumpHandler.labels());
-    previousBlock.addSuccessor(loopEntry);
-    open(loopEntry);
-
-    localsHandler.beginLoopHeader(loopEntry);
-    return jumpHandler;
-  }
-
-  /**
-   * Ends the loop:
-   * - creates a new block and adds it as successor to the [branchExitBlock] and
-   *   any blocks that end in break.
-   * - opens the new block (setting as [current]).
-   * - notifies the locals handler that we're exiting a loop.
-   * [savedLocals] are the locals from the end of the loop condition.
-   * [branchExitBlock] is the exit (branching) block of the condition. Generally
-   * this is not the top of the loop, since this would lead to critical edges.
-   * It is null for degenerate do-while loops that have
-   * no back edge because they abort (throw/return/break in the body and have
-   * no continues).
-   */
-  void endLoop(HBasicBlock loopEntry,
-               HBasicBlock branchExitBlock,
-               JumpHandler jumpHandler,
-               LocalsHandler savedLocals) {
-    HBasicBlock loopExitBlock = addNewBlock();
-
-    List<LocalsHandler> breakHandlers = <LocalsHandler>[];
-    // Collect data for the successors and the phis at each break.
-    jumpHandler.forEachBreak((HBreak breakInstruction, LocalsHandler locals) {
-      breakInstruction.block.addSuccessor(loopExitBlock);
-      breakHandlers.add(locals);
-    });
-
-    // The exit block is a successor of the loop condition if it is reached.
-    // We don't add the successor in the case of a while/for loop that aborts
-    // because the caller of endLoop will be wiring up a special empty else
-    // block instead.
-    if (branchExitBlock != null) {
-      branchExitBlock.addSuccessor(loopExitBlock);
-    }
-    // Update the phis at the loop entry with the current values of locals.
-    localsHandler.endLoop(loopEntry);
-
-    // Start generating code for the exit block.
-    open(loopExitBlock);
-
-    // Create a new localsHandler for the loopExitBlock with the correct phis.
-    if (!breakHandlers.isEmpty) {
-      if (branchExitBlock != null) {
-        // Add the values of the locals at the end of the condition block to
-        // the phis.  These are the values that flow to the exit if the
-        // condition fails.
-        breakHandlers.add(savedLocals);
-      }
-      localsHandler = savedLocals.mergeMultiple(breakHandlers, loopExitBlock);
-    } else {
-      localsHandler = savedLocals;
-    }
-  }
-
-  HSubGraphBlockInformation wrapStatementGraph(SubGraph statements) {
-    if (statements == null) return null;
-    return new HSubGraphBlockInformation(statements);
-  }
-
-  HSubExpressionBlockInformation wrapExpressionGraph(SubExpression expression) {
-    if (expression == null) return null;
-    return new HSubExpressionBlockInformation(expression);
-  }
-
-  // For while loops, initializer and update are null.
-  // The condition function must return a boolean result.
-  // None of the functions must leave anything on the stack.
-  void handleLoop(ast.Node loop,
-                  void initialize(),
-                  HInstruction condition(),
-                  void update(),
-                  void body()) {
-    // Generate:
-    //  <initializer>
-    //  loop-entry:
-    //    if (!<condition>) goto loop-exit;
-    //    <body>
-    //    <updates>
-    //    goto loop-entry;
-    //  loop-exit:
-
-    localsHandler.startLoop(loop);
-
-    // The initializer.
-    SubExpression initializerGraph = null;
-    HBasicBlock startBlock;
-    if (initialize != null) {
-      HBasicBlock initializerBlock = openNewBlock();
-      startBlock = initializerBlock;
-      initialize();
-      assert(!isAborted());
-      initializerGraph =
-          new SubExpression(initializerBlock, current);
-    }
-
-    loopNesting++;
-    JumpHandler jumpHandler = beginLoopHeader(loop);
-    HLoopInformation loopInfo = current.loopInformation;
-    HBasicBlock conditionBlock = current;
-    if (startBlock == null) startBlock = conditionBlock;
-
-    HInstruction conditionInstruction = condition();
-    HBasicBlock conditionEndBlock =
-        close(new HLoopBranch(conditionInstruction));
-    SubExpression conditionExpression =
-        new SubExpression(conditionBlock, conditionEndBlock);
-
-    // Save the values of the local variables at the end of the condition
-    // block.  These are the values that will flow to the loop exit if the
-    // condition fails.
-    LocalsHandler savedLocals = new LocalsHandler.from(localsHandler);
-
-    // The body.
-    HBasicBlock beginBodyBlock = addNewBlock();
-    conditionEndBlock.addSuccessor(beginBodyBlock);
-    open(beginBodyBlock);
-
-    localsHandler.enterLoopBody(loop);
-    body();
-
-    SubGraph bodyGraph = new SubGraph(beginBodyBlock, lastOpenedBlock);
-    HBasicBlock bodyBlock = current;
-    if (current != null) close(new HGoto());
-
-    SubExpression updateGraph;
-
-    bool loopIsDegenerate = !jumpHandler.hasAnyContinue() && bodyBlock == null;
-    if (!loopIsDegenerate) {
-      // Update.
-      // We create an update block, even when we are in a while loop. There the
-      // update block is the jump-target for continue statements. We could avoid
-      // the creation if there is no continue, but for now we always create it.
-      HBasicBlock updateBlock = addNewBlock();
-
-      List<LocalsHandler> continueHandlers = <LocalsHandler>[];
-      jumpHandler.forEachContinue((HContinue instruction,
-                                   LocalsHandler locals) {
-        instruction.block.addSuccessor(updateBlock);
-        continueHandlers.add(locals);
-      });
-
-
-      if (bodyBlock != null) {
-        continueHandlers.add(localsHandler);
-        bodyBlock.addSuccessor(updateBlock);
-      }
-
-      open(updateBlock);
-      localsHandler =
-          continueHandlers[0].mergeMultiple(continueHandlers, updateBlock);
-
-      HLabeledBlockInformation labelInfo;
-      List<LabelDefinition> labels = jumpHandler.labels();
-      JumpTarget target = elements.getTargetDefinition(loop);
-      if (!labels.isEmpty) {
-        beginBodyBlock.setBlockFlow(
-            new HLabeledBlockInformation(
-                new HSubGraphBlockInformation(bodyGraph),
-                jumpHandler.labels(),
-                isContinue: true),
-            updateBlock);
-      } else if (target != null && target.isContinueTarget) {
-        beginBodyBlock.setBlockFlow(
-            new HLabeledBlockInformation.implicit(
-                new HSubGraphBlockInformation(bodyGraph),
-                target,
-                isContinue: true),
-            updateBlock);
-      }
-
-      localsHandler.enterLoopUpdates(loop);
-
-      update();
-
-      HBasicBlock updateEndBlock = close(new HGoto());
-      // The back-edge completing the cycle.
-      updateEndBlock.addSuccessor(conditionBlock);
-      updateGraph = new SubExpression(updateBlock, updateEndBlock);
-
-      // Avoid a critical edge from the condition to the loop-exit body.
-      HBasicBlock conditionExitBlock = addNewBlock();
-      open(conditionExitBlock);
-      close(new HGoto());
-      conditionEndBlock.addSuccessor(conditionExitBlock);
-
-      endLoop(conditionBlock, conditionExitBlock, jumpHandler, savedLocals);
-
-      conditionBlock.postProcessLoopHeader();
-      HLoopBlockInformation info =
-          new HLoopBlockInformation(
-              HLoopBlockInformation.loopType(loop),
-              wrapExpressionGraph(initializerGraph),
-              wrapExpressionGraph(conditionExpression),
-              wrapStatementGraph(bodyGraph),
-              wrapExpressionGraph(updateGraph),
-              conditionBlock.loopInformation.target,
-              conditionBlock.loopInformation.labels,
-              sourceFileLocationForBeginToken(loop),
-              sourceFileLocationForEndToken(loop));
-
-      startBlock.setBlockFlow(info, current);
-      loopInfo.loopBlockInformation = info;
-    } else {
-      // The body of the for/while loop always aborts, so there is no back edge.
-      // We turn the code into:
-      // if (condition) {
-      //   body;
-      // } else {
-      //   // We always create an empty else block to avoid critical edges.
-      // }
-      //
-      // If there is any break in the body, we attach a synthetic
-      // label to the if.
-      HBasicBlock elseBlock = addNewBlock();
-      open(elseBlock);
-      close(new HGoto());
-      // Pass the elseBlock as the branchBlock, because that's the block we go
-      // to just before leaving the 'loop'.
-      endLoop(conditionBlock, elseBlock, jumpHandler, savedLocals);
-
-      SubGraph elseGraph = new SubGraph(elseBlock, elseBlock);
-      // Remove the loop information attached to the header.
-      conditionBlock.loopInformation = null;
-
-      // Remove the [HLoopBranch] instruction and replace it with
-      // [HIf].
-      HInstruction condition = conditionEndBlock.last.inputs[0];
-      conditionEndBlock.addAtExit(new HIf(condition));
-      conditionEndBlock.addSuccessor(elseBlock);
-      conditionEndBlock.remove(conditionEndBlock.last);
-      HIfBlockInformation info =
-          new HIfBlockInformation(
-              wrapExpressionGraph(conditionExpression),
-              wrapStatementGraph(bodyGraph),
-              wrapStatementGraph(elseGraph));
-
-      conditionEndBlock.setBlockFlow(info, current);
-      HIf ifBlock = conditionEndBlock.last;
-      ifBlock.blockInformation = conditionEndBlock.blockFlow;
-
-      // If the body has any break, attach a synthesized label to the
-      // if block.
-      if (jumpHandler.hasAnyBreak()) {
-        JumpTarget target = elements.getTargetDefinition(loop);
-        LabelDefinition label = target.addLabel(null, 'loop');
-        label.setBreakTarget();
-        SubGraph labelGraph = new SubGraph(conditionBlock, current);
-        HLabeledBlockInformation labelInfo = new HLabeledBlockInformation(
-                new HSubGraphBlockInformation(labelGraph),
-                <LabelDefinition>[label]);
-
-        conditionBlock.setBlockFlow(labelInfo, current);
-
-        jumpHandler.forEachBreak((HBreak breakInstruction, _) {
-          HBasicBlock block = breakInstruction.block;
-          block.addAtExit(new HBreak.toLabel(label));
-          block.remove(breakInstruction);
-        });
-      }
-    }
-    jumpHandler.close();
-    loopNesting--;
-  }
-
-  visitFor(ast.For node) {
-    assert(isReachable);
-    assert(node.body != null);
-    void buildInitializer() {
-      ast.Node initializer = node.initializer;
-      if (initializer == null) return;
-      visit(initializer);
-      if (initializer.asExpression() != null) {
-        pop();
-      }
-    }
-    HInstruction buildCondition() {
-      if (node.condition == null) {
-        return graph.addConstantBool(true, compiler);
-      }
-      visit(node.condition);
-      return popBoolified();
-    }
-    void buildUpdate() {
-      for (ast.Expression expression in node.update) {
-        visit(expression);
-        assert(!isAborted());
-        // The result of the update instruction isn't used, and can just
-        // be dropped.
-        HInstruction updateInstruction = pop();
-      }
-    }
-    void buildBody() {
-      visit(node.body);
-    }
-    handleLoop(node, buildInitializer, buildCondition, buildUpdate, buildBody);
-  }
-
-  visitWhile(ast.While node) {
-    assert(isReachable);
-    HInstruction buildCondition() {
-      visit(node.condition);
-      return popBoolified();
-    }
-    handleLoop(node,
-               () {},
-               buildCondition,
-               () {},
-               () { visit(node.body); });
-  }
-
-  visitDoWhile(ast.DoWhile node) {
-    assert(isReachable);
-    LocalsHandler savedLocals = new LocalsHandler.from(localsHandler);
-    localsHandler.startLoop(node);
-    loopNesting++;
-    JumpHandler jumpHandler = beginLoopHeader(node);
-    HLoopInformation loopInfo = current.loopInformation;
-    HBasicBlock loopEntryBlock = current;
-    HBasicBlock bodyEntryBlock = current;
-    JumpTarget target = elements.getTargetDefinition(node);
-    bool hasContinues = target != null && target.isContinueTarget;
-    if (hasContinues) {
-      // Add extra block to hang labels on.
-      // It doesn't currently work if they are on the same block as the
-      // HLoopInfo. The handling of HLabeledBlockInformation will visit a
-      // SubGraph that starts at the same block again, so the HLoopInfo is
-      // either handled twice, or it's handled after the labeled block info,
-      // both of which generate the wrong code.
-      // Using a separate block is just a simple workaround.
-      bodyEntryBlock = openNewBlock();
-    }
-    localsHandler.enterLoopBody(node);
-    visit(node.body);
-
-    // If there are no continues we could avoid the creation of the condition
-    // block. This could also lead to a block having multiple entries and exits.
-    HBasicBlock bodyExitBlock;
-    bool isAbortingBody = false;
-    if (current != null) {
-      bodyExitBlock = close(new HGoto());
-    } else {
-      isAbortingBody = true;
-      bodyExitBlock = lastOpenedBlock;
-    }
-
-    SubExpression conditionExpression;
-    bool loopIsDegenerate = isAbortingBody && !hasContinues;
-    if (!loopIsDegenerate) {
-      HBasicBlock conditionBlock = addNewBlock();
-
-      List<LocalsHandler> continueHandlers = <LocalsHandler>[];
-      jumpHandler.forEachContinue((HContinue instruction,
-                                   LocalsHandler locals) {
-        instruction.block.addSuccessor(conditionBlock);
-        continueHandlers.add(locals);
-      });
-
-      if (!isAbortingBody) {
-        bodyExitBlock.addSuccessor(conditionBlock);
-      }
-
-      if (!continueHandlers.isEmpty) {
-        if (!isAbortingBody) continueHandlers.add(localsHandler);
-        localsHandler =
-            savedLocals.mergeMultiple(continueHandlers, conditionBlock);
-        SubGraph bodyGraph = new SubGraph(bodyEntryBlock, bodyExitBlock);
-        List<LabelDefinition> labels = jumpHandler.labels();
-        HSubGraphBlockInformation bodyInfo =
-            new HSubGraphBlockInformation(bodyGraph);
-        HLabeledBlockInformation info;
-        if (!labels.isEmpty) {
-          info = new HLabeledBlockInformation(bodyInfo, labels,
-                                              isContinue: true);
-        } else {
-          info = new HLabeledBlockInformation.implicit(bodyInfo, target,
-                                                       isContinue: true);
-        }
-        bodyEntryBlock.setBlockFlow(info, conditionBlock);
-      }
-      open(conditionBlock);
-
-      visit(node.condition);
-      assert(!isAborted());
-      HInstruction conditionInstruction = popBoolified();
-      HBasicBlock conditionEndBlock = close(
-          new HLoopBranch(conditionInstruction, HLoopBranch.DO_WHILE_LOOP));
-
-      HBasicBlock avoidCriticalEdge = addNewBlock();
-      conditionEndBlock.addSuccessor(avoidCriticalEdge);
-      open(avoidCriticalEdge);
-      close(new HGoto());
-      avoidCriticalEdge.addSuccessor(loopEntryBlock); // The back-edge.
-
-      conditionExpression =
-          new SubExpression(conditionBlock, conditionEndBlock);
-
-      // Avoid a critical edge from the condition to the loop-exit body.
-      HBasicBlock conditionExitBlock = addNewBlock();
-      open(conditionExitBlock);
-      close(new HGoto());
-      conditionEndBlock.addSuccessor(conditionExitBlock);
-
-      endLoop(loopEntryBlock, conditionExitBlock, jumpHandler, localsHandler);
-
-      loopEntryBlock.postProcessLoopHeader();
-      SubGraph bodyGraph = new SubGraph(loopEntryBlock, bodyExitBlock);
-      HLoopBlockInformation loopBlockInfo =
-          new HLoopBlockInformation(
-              HLoopBlockInformation.DO_WHILE_LOOP,
-              null,
-              wrapExpressionGraph(conditionExpression),
-              wrapStatementGraph(bodyGraph),
-              null,
-              loopEntryBlock.loopInformation.target,
-              loopEntryBlock.loopInformation.labels,
-              sourceFileLocationForBeginToken(node),
-              sourceFileLocationForEndToken(node));
-      loopEntryBlock.setBlockFlow(loopBlockInfo, current);
-      loopInfo.loopBlockInformation = loopBlockInfo;
-    } else {
-      // Since the loop has no back edge, we remove the loop information on the
-      // header.
-      loopEntryBlock.loopInformation = null;
-
-      if (jumpHandler.hasAnyBreak()) {
-        // Null branchBlock because the body of the do-while loop always aborts,
-        // so we never get to the condition.
-        endLoop(loopEntryBlock, null, jumpHandler, localsHandler);
-
-        // Since the body of the loop has a break, we attach a synthesized label
-        // to the body.
-        SubGraph bodyGraph = new SubGraph(bodyEntryBlock, bodyExitBlock);
-        JumpTarget target = elements.getTargetDefinition(node);
-        LabelDefinition label = target.addLabel(null, 'loop');
-        label.setBreakTarget();
-        HLabeledBlockInformation info = new HLabeledBlockInformation(
-            new HSubGraphBlockInformation(bodyGraph), <LabelDefinition>[label]);
-        loopEntryBlock.setBlockFlow(info, current);
-        jumpHandler.forEachBreak((HBreak breakInstruction, _) {
-          HBasicBlock block = breakInstruction.block;
-          block.addAtExit(new HBreak.toLabel(label));
-          block.remove(breakInstruction);
-        });
-      }
-    }
-    jumpHandler.close();
-    loopNesting--;
-  }
-
-  visitFunctionExpression(ast.FunctionExpression node) {
-    ClosureClassMap nestedClosureData =
-        compiler.closureToClassMapper.getMappingForNestedFunction(node);
-    assert(nestedClosureData != null);
-    assert(nestedClosureData.closureClassElement != null);
-    ClosureClassElement closureClassElement =
-        nestedClosureData.closureClassElement;
-    FunctionElement callElement = nestedClosureData.callElement;
-    // TODO(ahe): This should be registered in codegen, not here.
-    // TODO(johnniwinther): Is [registerStaticUse] equivalent to
-    // [addToWorkList]?
-    registry.registerStaticUse(callElement);
-    // TODO(ahe): This should be registered in codegen, not here.
-    registry.registerInstantiatedClass(closureClassElement);
-
-    List<HInstruction> capturedVariables = <HInstruction>[];
-    closureClassElement.closureFields.forEach((ClosureFieldElement field) {
-      Local capturedLocal =
-          nestedClosureData.getLocalVariableForClosureField(field);
-      assert(capturedLocal != null);
-      capturedVariables.add(localsHandler.readLocal(capturedLocal));
-    });
-
-    TypeMask type =
-        new TypeMask.nonNullExact(compiler.functionClass, compiler.world);
-    push(new HForeignNew(closureClassElement, type, capturedVariables));
-
-    Element methodElement = nestedClosureData.closureElement;
-    if (compiler.backend.methodNeedsRti(methodElement)) {
-      registry.registerClosureWithFreeTypeVariables(methodElement);
-    }
-  }
-
-  visitFunctionDeclaration(ast.FunctionDeclaration node) {
-    assert(isReachable);
-    visit(node.function);
-    LocalFunctionElement localFunction =
-        elements.getFunctionDefinition(node.function);
-    localsHandler.updateLocal(localFunction, pop());
-  }
-
-  visitIdentifier(ast.Identifier node) {
-    if (node.isThis()) {
-      stack.add(localsHandler.readThis());
-    } else {
-      compiler.internalError(node,
-          "SsaFromAstMixin.visitIdentifier on non-this.");
-    }
-  }
-
-  visitIf(ast.If node) {
-    assert(isReachable);
-    handleIf(node,
-             () => visit(node.condition),
-             () => visit(node.thenPart),
-             node.elsePart != null ? () => visit(node.elsePart) : null);
-  }
-
-  void handleIf(ast.Node diagnosticNode,
-                void visitCondition(), void visitThen(), void visitElse()) {
-    SsaBranchBuilder branchBuilder = new SsaBranchBuilder(this, diagnosticNode);
-    branchBuilder.handleIf(visitCondition, visitThen, visitElse);
-  }
-
-  void visitLogicalAndOr(ast.Send node, ast.Operator op) {
-    SsaBranchBuilder branchBuilder = new SsaBranchBuilder(this, node);
-    branchBuilder.handleLogicalAndOrWithLeftNode(
-        node.receiver,
-        () { visit(node.argumentsNode); },
-        isAnd: ("&&" == op.source));
-  }
-
-  void visitLogicalNot(ast.Send node) {
-    assert(node.argumentsNode is ast.Prefix);
-    visit(node.receiver);
-    HNot not = new HNot(popBoolified(), backend.boolType);
-    pushWithPosition(not, node);
-  }
-
-  void visitUnary(ast.Send node, ast.Operator op) {
-    assert(node.argumentsNode is ast.Prefix);
-    visit(node.receiver);
-    assert(!identical(op.token.kind, PLUS_TOKEN));
-    HInstruction operand = pop();
-
-    // See if we can constant-fold right away. This avoids rewrites later on.
-    if (operand is HConstant) {
-      UnaryOperation operation = constantSystem.lookupUnary(op.source);
-      HConstant constant = operand;
-      ConstantValue folded = operation.fold(constant.constant);
-      if (folded != null) {
-        stack.add(graph.addConstant(folded, compiler));
-        return;
-      }
-    }
-
-    pushInvokeDynamic(node, elements.getSelector(node), [operand]);
-  }
-
-  void visitBinary(HInstruction left,
-                   ast.Operator op,
-                   HInstruction right,
-                   Selector selector,
-                   ast.Send send) {
-    switch (op.source) {
-      case "===":
-        pushWithPosition(
-            new HIdentity(left, right, null, backend.boolType), op);
-        return;
-      case "!==":
-        HIdentity eq = new HIdentity(left, right, null, backend.boolType);
-        add(eq);
-        pushWithPosition(new HNot(eq, backend.boolType), op);
-        return;
-    }
-
-    pushInvokeDynamic(send, selector, [left, right], location: op);
-    if (op.source == '!=') {
-      pushWithPosition(new HNot(popBoolified(), backend.boolType), op);
-    }
-  }
-
-  HInstruction generateInstanceSendReceiver(ast.Send send) {
-    assert(Elements.isInstanceSend(send, elements));
-    if (send.receiver == null) {
-      return localsHandler.readThis();
-    }
-    visit(send.receiver);
-    return pop();
-  }
-
-  String noSuchMethodTargetSymbolString(ErroneousElement error,
-                                        [String prefix]) {
-    String result = error.name;
-    if (prefix == "set") return "$result=";
-    return result;
-  }
-
-  /**
-   * Returns a set of interceptor classes that contain the given
-   * [selector].
-   */
-  void generateInstanceGetterWithCompiledReceiver(ast.Send send,
-                                                  Selector selector,
-                                                  HInstruction receiver) {
-    assert(Elements.isInstanceSend(send, elements));
-    assert(selector.isGetter);
-    pushInvokeDynamic(send, selector, [receiver]);
-  }
-
-  /// Inserts a call to checkDeferredIsLoaded if the send has a prefix that
-  /// resolves to a deferred library.
-  void generateIsDeferredLoadedCheckIfNeeded(ast.Send node) {
-    DeferredLoadTask deferredTask = compiler.deferredLoadTask;
-    PrefixElement prefixElement =
-         deferredTask.deferredPrefixElement(node, elements);
-    if (prefixElement != null) {
-      String loadId =
-          deferredTask.importDeferName[prefixElement.deferredImport];
-      HInstruction loadIdConstant = addConstantString(loadId);
-      String uri = prefixElement.deferredImport.uri.dartString.slowToString();
-      HInstruction uriConstant = addConstantString(uri);
-      Element helper = backend.getCheckDeferredIsLoaded();
-      pushInvokeStatic(node, helper, [loadIdConstant, uriConstant]);
-      pop();
-    }
-  }
-
-  void generateGetter(ast.Send send, Element element) {
-    if (element != null && element.isForeign(backend)) {
-      visitForeignGetter(send);
-    } else if (Elements.isStaticOrTopLevelField(element)) {
-      ConstantExpression constant;
-      if (element.isField && !element.isAssignable) {
-        // A static final or const. Get its constant value and inline it if
-        // the value can be compiled eagerly.
-        constant = backend.constants.getConstantForVariable(element);
-      }
-      if (constant != null) {
-        ConstantValue value = constant.value;
-        HConstant instruction;
-        // Constants that are referred via a deferred prefix should be referred
-        // by reference.
-        PrefixElement prefix = compiler.deferredLoadTask
-            .deferredPrefixElement(send, elements);
-        if (prefix != null) {
-          instruction = graph.addDeferredConstant(value, prefix, compiler);
-        } else {
-          instruction = graph.addConstant(value, compiler);
-        }
-        stack.add(instruction);
-        // The inferrer may have found a better type than the constant
-        // handler in the case of lists, because the constant handler
-        // does not look at elements in the list.
-        TypeMask type =
-            TypeMaskFactory.inferredTypeForElement(element, compiler);
-        if (!type.containsAll(compiler.world) &&
-            !instruction.isConstantNull()) {
-          // TODO(13429): The inferrer should know that an element
-          // cannot be null.
-          instruction.instructionType = type.nonNullable();
-        }
-      } else if (element.isField && isLazilyInitialized(element)) {
-        HInstruction instruction = new HLazyStatic(
-            element,
-            TypeMaskFactory.inferredTypeForElement(element, compiler));
-        push(instruction);
-      } else {
-        if (element.isGetter) {
-          pushInvokeStatic(send, element, <HInstruction>[]);
-        } else {
-          // TODO(5346): Try to avoid the need for calling [declaration] before
-          // creating an [HStatic].
-          HInstruction instruction = new HStatic(
-              element.declaration,
-              TypeMaskFactory.inferredTypeForElement(element, compiler));
-          push(instruction);
-        }
-      }
-    } else if (Elements.isInstanceSend(send, elements)) {
-      HInstruction receiver = generateInstanceSendReceiver(send);
-      generateInstanceGetterWithCompiledReceiver(
-          send, elements.getSelector(send), receiver);
-    } else if (Elements.isStaticOrTopLevelFunction(element)) {
-      // TODO(5346): Try to avoid the need for calling [declaration] before
-      // creating an [HStatic].
-      push(new HStatic(element.declaration, backend.nonNullType));
-      // TODO(ahe): This should be registered in codegen.
-      registry.registerGetOfStaticFunction(element.declaration);
-    } else if (Elements.isErroneousElement(element)) {
-      // An erroneous element indicates an unresolved static getter.
-      generateThrowNoSuchMethod(send,
-                                noSuchMethodTargetSymbolString(element, 'get'),
-                                argumentNodes: const Link<ast.Node>());
-    } else {
-      LocalElement local = element;
-      stack.add(localsHandler.readLocal(local));
-    }
-  }
-
-  void generateInstanceSetterWithCompiledReceiver(ast.Send send,
-                                                  HInstruction receiver,
-                                                  HInstruction value,
-                                                  {Selector selector,
-                                                   ast.Node location}) {
-    assert(send == null || Elements.isInstanceSend(send, elements));
-    if (selector == null) {
-      assert(send != null);
-      selector = elements.getSelector(send);
-    }
-    if (location == null) {
-      assert(send != null);
-      location = send;
-    }
-    assert(selector.isSetter);
-    pushInvokeDynamic(location, selector, [receiver, value]);
-    pop();
-    stack.add(value);
-  }
-
-  void generateNonInstanceSetter(ast.SendSet send,
-                                 Element element,
-                                 HInstruction value,
-                                 {ast.Node location}) {
-    assert(send == null || !Elements.isInstanceSend(send, elements));
-    if (location == null) {
-      assert(send != null);
-      location = send;
-    }
-    if (Elements.isStaticOrTopLevelField(element)) {
-      if (element.isSetter) {
-        pushInvokeStatic(location, element, <HInstruction>[value]);
-        pop();
-      } else {
-        VariableElement field = element;
-        value =
-            potentiallyCheckType(value, field.type);
-        addWithPosition(new HStaticStore(element, value), location);
-      }
-      stack.add(value);
-    } else if (Elements.isErroneousElement(element)) {
-      List<HInstruction> arguments =
-          send == null ? const <HInstruction>[] : <HInstruction>[value];
-      // An erroneous element indicates an unresolved static setter.
-      generateThrowNoSuchMethod(location,
-                                noSuchMethodTargetSymbolString(element, 'set'),
-                                argumentValues: arguments);
-    } else {
-      stack.add(value);
-      LocalElement local = element;
-      // If the value does not already have a name, give it here.
-      if (value.sourceElement == null) {
-        value.sourceElement = local;
-      }
-      HInstruction checked =
-          potentiallyCheckType(value, local.type);
-      if (!identical(checked, value)) {
-        pop();
-        stack.add(checked);
-      }
-      HInstruction trusted =
-          potentiallyBuildTypeHint(checked, local.type);
-      if (!identical(trusted, checked)) {
-        pop();
-        push(trusted);
-      }
-
-      localsHandler.updateLocal(local, trusted);
-    }
-  }
-
-  HInstruction invokeInterceptor(HInstruction receiver) {
-    HInterceptor interceptor = new HInterceptor(receiver, backend.nonNullType);
-    add(interceptor);
-    return interceptor;
-  }
-
-  HForeign createForeign(js.Template code,
-                         TypeMask type,
-                         List<HInstruction> inputs) {
-    return new HForeign(code, type, inputs);
-  }
-
-  HLiteralList buildLiteralList(List<HInstruction> inputs) {
-    return new HLiteralList(inputs, backend.extendableArrayType);
-  }
-
-  // TODO(karlklose): change construction of the representations to be GVN'able
-  // (dartbug.com/7182).
-  HInstruction buildTypeArgumentRepresentations(DartType type) {
-    // Compute the representation of the type arguments, including access
-    // to the runtime type information for type variables as instructions.
-    if (type.isTypeVariable) {
-      return buildLiteralList(<HInstruction>[addTypeVariableReference(type)]);
-    } else {
-      assert(type.element.isClass);
-      InterfaceType interface = type;
-      List<HInstruction> inputs = <HInstruction>[];
-      bool first = true;
-      List<String> templates = <String>[];
-      for (DartType argument in interface.typeArguments) {
-        templates.add(rti.getTypeRepresentationWithHashes(argument, (variable) {
-          HInstruction runtimeType = addTypeVariableReference(variable);
-          inputs.add(runtimeType);
-        }));
-      }
-      String template = '[${templates.join(', ')}]';
-      // TODO(sra): This is a fresh template each time.  We can't let the
-      // template manager build them.
-      js.Template code = js.js.uncachedExpressionTemplate(template);
-      HInstruction representation =
-        createForeign(code, backend.readableArrayType, inputs);
-      return representation;
-    }
-  }
-
-  visitOperatorSend(ast.Send node) {
-    ast.Operator op = node.selector;
-    if ("[]" == op.source) {
-      visitDynamicSend(node);
-    } else if ("&&" == op.source ||
-               "||" == op.source) {
-      visitLogicalAndOr(node, op);
-    } else if ("!" == op.source) {
-      visitLogicalNot(node);
-    } else if (node.argumentsNode is ast.Prefix) {
-      visitUnary(node, op);
-    } else if ("is" == op.source) {
-      visitIsSend(node);
-    } else if ("as" == op.source) {
-      visit(node.receiver);
-      HInstruction expression = pop();
-      DartType type = elements.getType(node.typeAnnotationFromIsCheckOrCast);
-      if (type.isMalformed) {
-        ErroneousElement element = type.element;
-        generateTypeError(node, element.message);
-      } else {
-        HInstruction converted = buildTypeConversion(
-            expression,
-            localsHandler.substInContext(type),
-            HTypeConversion.CAST_TYPE_CHECK);
-        if (converted != expression) add(converted);
-        stack.add(converted);
-      }
-    } else {
-      visit(node.receiver);
-      visit(node.argumentsNode);
-      var right = pop();
-      var left = pop();
-      visitBinary(left, op, right, elements.getSelector(node), node);
-    }
-  }
-
-  void visitIsSend(ast.Send node) {
-    visit(node.receiver);
-    HInstruction expression = pop();
-    bool isNot = node.isIsNotCheck;
-    DartType type = elements.getType(node.typeAnnotationFromIsCheckOrCast);
-    HInstruction instruction = buildIsNode(node, type, expression);
-    if (isNot) {
-      add(instruction);
-      instruction = new HNot(instruction, backend.boolType);
-    }
-    push(instruction);
-  }
-
-  HInstruction buildIsNode(ast.Node node,
-                           DartType type,
-                           HInstruction expression) {
-    type = localsHandler.substInContext(type).unalias(compiler);
-    if (type.isFunctionType) {
-      List arguments = [buildFunctionType(type), expression];
-      pushInvokeDynamic(
-          node, new Selector.call('_isTest', backend.jsHelperLibrary, 1),
-          arguments);
-      return new HIs.compound(type, expression, pop(), backend.boolType);
-    } else if (type.isTypeVariable) {
-      HInstruction runtimeType = addTypeVariableReference(type);
-      Element helper = backend.getCheckSubtypeOfRuntimeType();
-      List<HInstruction> inputs = <HInstruction>[expression, runtimeType];
-      pushInvokeStatic(null, helper, inputs, backend.boolType);
-      HInstruction call = pop();
-      return new HIs.variable(type, expression, call, backend.boolType);
-    } else if (RuntimeTypes.hasTypeArguments(type)) {
-      ClassElement element = type.element;
-      Element helper = backend.getCheckSubtype();
-      HInstruction representations =
-          buildTypeArgumentRepresentations(type);
-      add(representations);
-      String operator = backend.namer.operatorIs(element);
-      HInstruction isFieldName = addConstantString(operator);
-      HInstruction asFieldName = compiler.world.hasAnyStrictSubtype(element)
-          ? addConstantString(backend.namer.substitutionName(element))
-          : graph.addConstantNull(compiler);
-      List<HInstruction> inputs = <HInstruction>[expression,
-                                                 isFieldName,
-                                                 representations,
-                                                 asFieldName];
-      pushInvokeStatic(node, helper, inputs, backend.boolType);
-      HInstruction call = pop();
-      return new HIs.compound(type, expression, call, backend.boolType);
-    } else if (type.isMalformed) {
-      ErroneousElement element = type.element;
-      generateTypeError(node, element.message);
-      HInstruction call = pop();
-      return new HIs.compound(type, expression, call, backend.boolType);
-    } else {
-      if (backend.hasDirectCheckFor(type)) {
-        return new HIs.direct(type, expression, backend.boolType);
-      }
-      // TODO(johnniwinther): Avoid interceptor if unneeded.
-      return new HIs.raw(
-          type, expression, invokeInterceptor(expression), backend.boolType);
-    }
-  }
-
-  HInstruction buildFunctionType(FunctionType type) {
-    type.accept(new TypeBuilder(compiler.world), this);
-    return pop();
-  }
-
-  void addDynamicSendArgumentsToList(ast.Send node, List<HInstruction> list) {
-    Selector selector = elements.getSelector(node);
-    if (selector.namedArgumentCount == 0) {
-      addGenericSendArgumentsToList(node.arguments, list);
-    } else {
-      // Visit positional arguments and add them to the list.
-      Link<ast.Node> arguments = node.arguments;
-      int positionalArgumentCount = selector.positionalArgumentCount;
-      for (int i = 0;
-           i < positionalArgumentCount;
-           arguments = arguments.tail, i++) {
-        visit(arguments.head);
-        list.add(pop());
-      }
-
-      // Visit named arguments and add them into a temporary map.
-      Map<String, HInstruction> instructions =
-          new Map<String, HInstruction>();
-      List<String> namedArguments = selector.namedArguments;
-      int nameIndex = 0;
-      for (; !arguments.isEmpty; arguments = arguments.tail) {
-        visit(arguments.head);
-        instructions[namedArguments[nameIndex++]] = pop();
-      }
-
-      // Iterate through the named arguments to add them to the list
-      // of instructions, in an order that can be shared with
-      // selectors with the same named arguments.
-      List<String> orderedNames = selector.getOrderedNamedArguments();
-      for (String name in orderedNames) {
-        list.add(instructions[name]);
-      }
-    }
-  }
-
-  /**
-   * Returns true if the arguments were compatible with the function signature.
-   *
-   * Invariant: [element] must be an implementation element.
-   */
-  bool addStaticSendArgumentsToList(Selector selector,
-                                    Link<ast.Node> arguments,
-                                    FunctionElement element,
-                                    List<HInstruction> list) {
-    assert(invariant(element, element.isImplementation));
-
-    HInstruction compileArgument(ast.Node argument) {
-      visit(argument);
-      return pop();
-    }
-
-    return selector.addArgumentsToList(arguments,
-                                       list,
-                                       element,
-                                       compileArgument,
-                                       handleConstantForOptionalParameter,
-                                       compiler.world);
-  }
-
-  void addGenericSendArgumentsToList(Link<ast.Node> link, List<HInstruction> list) {
-    for (; !link.isEmpty; link = link.tail) {
-      visit(link.head);
-      list.add(pop());
-    }
-  }
-
-  visitDynamicSend(ast.Send node) {
-    Selector selector = elements.getSelector(node);
-
-    List<HInstruction> inputs = <HInstruction>[];
-    HInstruction receiver = generateInstanceSendReceiver(node);
-    inputs.add(receiver);
-    addDynamicSendArgumentsToList(node, inputs);
-
-    pushInvokeDynamic(node, selector, inputs);
-    if (selector.isSetter || selector.isIndexSet) {
-      pop();
-      stack.add(inputs.last);
-    }
-  }
-
-  visitClosureSend(ast.Send node) {
-    Selector selector = elements.getSelector(node);
-    assert(node.receiver == null);
-    Element element = elements[node];
-    HInstruction closureTarget;
-    if (element == null) {
-      visit(node.selector);
-      closureTarget = pop();
-    } else {
-      LocalElement local = element;
-      closureTarget = localsHandler.readLocal(local);
-    }
-    var inputs = <HInstruction>[];
-    inputs.add(closureTarget);
-    addDynamicSendArgumentsToList(node, inputs);
-    Selector closureSelector = new Selector.callClosureFrom(selector);
-    pushWithPosition(
-        new HInvokeClosure(closureSelector, inputs, backend.dynamicType),
-        node);
-  }
-
-  void handleForeignJs(ast.Send node) {
-    Link<ast.Node> link = node.arguments;
-    // If the invoke is on foreign code, don't visit the first
-    // argument, which is the type, and the second argument,
-    // which is the foreign code.
-    if (link.isEmpty || link.tail.isEmpty) {
-      compiler.internalError(node.argumentsNode,
-          'At least two arguments expected.');
-    }
-    native.NativeBehavior nativeBehavior =
-        compiler.enqueuer.resolution.nativeEnqueuer.getNativeBehaviorOf(node);
-
-    List<HInstruction> inputs = <HInstruction>[];
-    addGenericSendArgumentsToList(link.tail.tail, inputs);
-
-    TypeMask ssaType =
-        TypeMaskFactory.fromNativeBehavior(nativeBehavior, compiler);
-
-    if (nativeBehavior.codeTemplate.isExpression) {
-      push(new HForeign(nativeBehavior.codeTemplate, ssaType, inputs,
-                        effects: nativeBehavior.sideEffects,
-                        nativeBehavior: nativeBehavior));
-    } else {
-      push(new HForeign(nativeBehavior.codeTemplate, ssaType, inputs,
-                        isStatement: true,
-                        effects: nativeBehavior.sideEffects,
-                        nativeBehavior: nativeBehavior,
-                        canThrow: true));
-    }
-  }
-
-  void handleJsStringConcat(ast.Send node) {
-    List<HInstruction> inputs = <HInstruction>[];
-    addGenericSendArgumentsToList(node.arguments, inputs);
-    if (inputs.length != 2) {
-      compiler.internalError(node.argumentsNode, 'Two arguments expected.');
-    }
-    push(new HStringConcat(inputs[0], inputs[1], node, backend.stringType));
-  }
-
-  void handleForeignJsCurrentIsolateContext(ast.Send node) {
-    if (!node.arguments.isEmpty) {
-      compiler.internalError(node,
-          'Too many arguments to JS_CURRENT_ISOLATE_CONTEXT.');
-    }
-
-    if (!compiler.hasIsolateSupport) {
-      // If the isolate library is not used, we just generate code
-      // to fetch the current isolate.
-      String name = backend.namer.currentIsolate;
-      push(new HForeign(js.js.parseForeignJS(name),
-                        backend.dynamicType,
-                        <HInstruction>[]));
-    } else {
-      // Call a helper method from the isolate library. The isolate
-      // library uses its own isolate structure, that encapsulates
-      // Leg's isolate.
-      Element element = backend.isolateHelperLibrary.find('_currentIsolate');
-      if (element == null) {
-        compiler.internalError(node,
-            'Isolate library and compiler mismatch.');
-      }
-      pushInvokeStatic(null, element, [], backend.dynamicType);
-    }
-  }
-
-  void handleForeingJsGetFlag(ast.Send node) {
-    List<ast.Node> arguments = node.arguments.toList();
-     ast.Node argument;
-     switch (arguments.length) {
-     case 0:
-       compiler.reportError(
-           node, MessageKind.GENERIC,
-           {'text': 'Error: Expected one argument to JS_GET_FLAG.'});
-       return;
-     case 1:
-       argument = arguments[0];
-       break;
-     default:
-       for (int i = 1; i < arguments.length; i++) {
-         compiler.reportError(
-             arguments[i], MessageKind.GENERIC,
-             {'text': 'Error: Extra argument to JS_GET_FLAG.'});
-       }
-       return;
-     }
-     ast.LiteralString string = argument.asLiteralString();
-     if (string == null) {
-       compiler.reportError(
-           argument, MessageKind.GENERIC,
-           {'text': 'Error: Expected a literal string.'});
-     }
-     String name = string.dartString.slowToString();
-     bool value = false;
-     if (name == 'MUST_RETAIN_METADATA') {
-       value = backend.mustRetainMetadata;
-     } else {
-       compiler.reportError(
-           node, MessageKind.GENERIC,
-           {'text': 'Error: Unknown internal flag "$name".'});
-     }
-     stack.add(graph.addConstantBool(value, compiler));
-  }
-
-  void handleForeignJsGetName(ast.Send node) {
-    List<ast.Node> arguments = node.arguments.toList();
-    ast.Node argument;
-    switch (arguments.length) {
-    case 0:
-      compiler.reportError(
-          node, MessageKind.GENERIC,
-          {'text': 'Error: Expected one argument to JS_GET_NAME.'});
-      return;
-    case 1:
-      argument = arguments[0];
-      break;
-    default:
-      for (int i = 1; i < arguments.length; i++) {
-        compiler.reportError(
-            arguments[i], MessageKind.GENERIC,
-            {'text': 'Error: Extra argument to JS_GET_NAME.'});
-      }
-      return;
-    }
-    ast.LiteralString string = argument.asLiteralString();
-    if (string == null) {
-      compiler.reportError(
-          argument, MessageKind.GENERIC,
-          {'text': 'Error: Expected a literal string.'});
-    }
-    stack.add(
-        addConstantString(
-            backend.namer.getNameForJsGetName(
-                argument, string.dartString.slowToString())));
-  }
-
-  void handleForeignJsEmbeddedGlobal(ast.Send node) {
-    List<ast.Node> arguments = node.arguments.toList();
-    ast.Node globalNameNode;
-    switch (arguments.length) {
-    case 0:
-    case 1:
-      compiler.reportError(
-          node, MessageKind.GENERIC,
-          {'text': 'Error: Expected two arguments to JS_EMBEDDED_GLOBAL.'});
-      return;
-    case 2:
-      // The type has been extracted earlier. We are only interested in the
-      // name in this function.
-      globalNameNode = arguments[1];
-      break;
-    default:
-      for (int i = 2; i < arguments.length; i++) {
-        compiler.reportError(
-            arguments[i], MessageKind.GENERIC,
-            {'text': 'Error: Extra argument to JS_EMBEDDED_GLOBAL.'});
-      }
-      return;
-    }
-    visit(arguments[1]);
-    HInstruction globalNameHNode = pop();
-    if (!globalNameHNode.isConstantString()) {
-      compiler.reportError(
-          arguments[1], MessageKind.GENERIC,
-          {'text': 'Error: Expected String as second argument '
-                   'to JS_EMBEDDED_GLOBAL.'});
-      return;
-    }
-    HConstant hConstant = globalNameHNode;
-    StringConstantValue constant = hConstant.constant;
-    String globalName = constant.primitiveValue.slowToString();
-    js.Template expr = js.js.expressionTemplateYielding(
-        backend.emitter.generateEmbeddedGlobalAccess(globalName));
-    native.NativeBehavior nativeBehavior =
-        compiler.enqueuer.resolution.nativeEnqueuer.getNativeBehaviorOf(node);
-    TypeMask ssaType =
-        TypeMaskFactory.fromNativeBehavior(nativeBehavior, compiler);
-    push(new HForeign(expr, ssaType, const []));
-  }
-
-  void handleJsInterceptorConstant(ast.Send node) {
-    // Single argument must be a TypeConstant which is converted into a
-    // InterceptorConstant.
-    if (!node.arguments.isEmpty && node.arguments.tail.isEmpty) {
-      ast.Node argument = node.arguments.head;
-      visit(argument);
-      HInstruction argumentInstruction = pop();
-      if (argumentInstruction is HConstant) {
-        ConstantValue argumentConstant = argumentInstruction.constant;
-        if (argumentConstant is TypeConstantValue) {
-          ConstantValue constant =
-              new InterceptorConstantValue(argumentConstant.representedType);
-          HInstruction instruction = graph.addConstant(constant, compiler);
-          stack.add(instruction);
-          return;
-        }
-      }
-    }
-    compiler.reportError(node,
-        MessageKind.WRONG_ARGUMENT_FOR_JS_INTERCEPTOR_CONSTANT);
-    stack.add(graph.addConstantNull(compiler));
-  }
-
-  void handleForeignJsCallInIsolate(ast.Send node) {
-    Link<ast.Node> link = node.arguments;
-    if (!compiler.hasIsolateSupport) {
-      // If the isolate library is not used, we just invoke the
-      // closure.
-      visit(link.tail.head);
-      Selector selector = new Selector.callClosure(0);
-      push(new HInvokeClosure(selector,
-                              <HInstruction>[pop()],
-                              backend.dynamicType));
-    } else {
-      // Call a helper method from the isolate library.
-      Element element = backend.isolateHelperLibrary.find('_callInIsolate');
-      if (element == null) {
-        compiler.internalError(node,
-            'Isolate library and compiler mismatch.');
-      }
-      List<HInstruction> inputs = <HInstruction>[];
-      addGenericSendArgumentsToList(link, inputs);
-      pushInvokeStatic(node, element, inputs, backend.dynamicType);
-    }
-  }
-
-  FunctionSignature handleForeignRawFunctionRef(ast.Send node, String name) {
-    if (node.arguments.isEmpty || !node.arguments.tail.isEmpty) {
-      compiler.internalError(node.argumentsNode,
-          '"$name" requires exactly one argument.');
-    }
-    ast.Node closure = node.arguments.head;
-    Element element = elements[closure];
-    if (!Elements.isStaticOrTopLevelFunction(element)) {
-      compiler.internalError(closure,
-          '"$name" requires a static or top-level method.');
-    }
-    FunctionElement function = element;
-    // TODO(johnniwinther): Try to eliminate the need to distinguish declaration
-    // and implementation signatures. Currently it is need because the
-    // signatures have different elements for parameters.
-    FunctionElement implementation = function.implementation;
-    FunctionSignature params = implementation.functionSignature;
-    if (params.optionalParameterCount != 0) {
-      compiler.internalError(closure,
-          '"$name" does not handle closure with optional parameters.');
-    }
-
-    registry.registerStaticUse(element);
-    push(new HForeign(js.js.expressionTemplateYielding(
-                          backend.namer.elementAccess(element)),
-                      backend.dynamicType,
-                      <HInstruction>[]));
-    return params;
-  }
-
-  void handleForeignDartClosureToJs(ast.Send node, String name) {
-    // TODO(ahe): This implements DART_CLOSURE_TO_JS and should probably take
-    // care to wrap the closure in another closure that saves the current
-    // isolate.
-    handleForeignRawFunctionRef(node, name);
-  }
-
-  void handleForeignSetCurrentIsolate(ast.Send node) {
-    if (node.arguments.isEmpty || !node.arguments.tail.isEmpty) {
-      compiler.internalError(node.argumentsNode,
-          'Exactly one argument required.');
-    }
-    visit(node.arguments.head);
-    String isolateName = backend.namer.currentIsolate;
-    SideEffects sideEffects = new SideEffects.empty();
-    sideEffects.setAllSideEffects();
-    push(new HForeign(js.js.parseForeignJS("$isolateName = #"),
-                      backend.dynamicType,
-                      <HInstruction>[pop()],
-                      effects: sideEffects));
-  }
-
-  void handleForeignCreateIsolate(ast.Send node) {
-    if (!node.arguments.isEmpty) {
-      compiler.internalError(node.argumentsNode, 'Too many arguments.');
-    }
-    String constructorName = backend.namer.isolateName;
-    push(new HForeign(js.js.parseForeignJS("new $constructorName()"),
-                      backend.dynamicType,
-                      <HInstruction>[]));
-  }
-
-  void handleForeignDartObjectJsConstructorFunction(ast.Send node) {
-    if (!node.arguments.isEmpty) {
-      compiler.internalError(node.argumentsNode, 'Too many arguments.');
-    }
-    push(new HForeign(js.js.expressionTemplateYielding(
-                          backend.namer.elementAccess(compiler.objectClass)),
-                      backend.dynamicType,
-                      <HInstruction>[]));
-  }
-
-  void handleForeignJsCurrentIsolate(ast.Send node) {
-    if (!node.arguments.isEmpty) {
-      compiler.internalError(node.argumentsNode, 'Too many arguments.');
-    }
-    push(new HForeign(js.js.parseForeignJS(backend.namer.currentIsolate),
-                      backend.dynamicType,
-                      <HInstruction>[]));
-  }
-
-  visitForeignSend(ast.Send node) {
-    Selector selector = elements.getSelector(node);
-    String name = selector.name;
-    if (name == 'JS') {
-      handleForeignJs(node);
-    } else if (name == 'JS_CURRENT_ISOLATE_CONTEXT') {
-      handleForeignJsCurrentIsolateContext(node);
-    } else if (name == 'JS_CALL_IN_ISOLATE') {
-      handleForeignJsCallInIsolate(node);
-    } else if (name == 'DART_CLOSURE_TO_JS') {
-      handleForeignDartClosureToJs(node, 'DART_CLOSURE_TO_JS');
-    } else if (name == 'RAW_DART_FUNCTION_REF') {
-      handleForeignRawFunctionRef(node, 'RAW_DART_FUNCTION_REF');
-    } else if (name == 'JS_SET_CURRENT_ISOLATE') {
-      handleForeignSetCurrentIsolate(node);
-    } else if (name == 'JS_CREATE_ISOLATE') {
-      handleForeignCreateIsolate(node);
-    } else if (name == 'JS_OPERATOR_IS_PREFIX') {
-      stack.add(addConstantString(backend.namer.operatorIsPrefix()));
-    } else if (name == 'JS_OBJECT_CLASS_NAME') {
-      String name = backend.namer.getRuntimeTypeName(compiler.objectClass);
-      stack.add(addConstantString(name));
-    } else if (name == 'JS_NULL_CLASS_NAME') {
-      String name = backend.namer.getRuntimeTypeName(compiler.nullClass);
-      stack.add(addConstantString(name));
-    } else if (name == 'JS_FUNCTION_CLASS_NAME') {
-      String name = backend.namer.getRuntimeTypeName(compiler.functionClass);
-      stack.add(addConstantString(name));
-    } else if (name == 'JS_OPERATOR_AS_PREFIX') {
-      stack.add(addConstantString(backend.namer.operatorAsPrefix()));
-    } else if (name == 'JS_SIGNATURE_NAME') {
-      stack.add(addConstantString(backend.namer.operatorSignature()));
-    } else if (name == 'JS_FUNCTION_TYPE_TAG') {
-      stack.add(addConstantString(backend.namer.functionTypeTag()));
-    } else if (name == 'JS_FUNCTION_TYPE_VOID_RETURN_TAG') {
-      stack.add(addConstantString(backend.namer.functionTypeVoidReturnTag()));
-    } else if (name == 'JS_FUNCTION_TYPE_RETURN_TYPE_TAG') {
-      stack.add(addConstantString(backend.namer.functionTypeReturnTypeTag()));
-    } else if (name ==
-               'JS_FUNCTION_TYPE_REQUIRED_PARAMETERS_TAG') {
-      stack.add(addConstantString(
-          backend.namer.functionTypeRequiredParametersTag()));
-    } else if (name ==
-               'JS_FUNCTION_TYPE_OPTIONAL_PARAMETERS_TAG') {
-      stack.add(addConstantString(
-          backend.namer.functionTypeOptionalParametersTag()));
-    } else if (name ==
-               'JS_FUNCTION_TYPE_NAMED_PARAMETERS_TAG') {
-      stack.add(addConstantString(
-          backend.namer.functionTypeNamedParametersTag()));
-    } else if (name == 'JS_DART_OBJECT_CONSTRUCTOR') {
-      handleForeignDartObjectJsConstructorFunction(node);
-    } else if (name == 'JS_IS_INDEXABLE_FIELD_NAME') {
-      Element element = backend.findHelper('JavaScriptIndexingBehavior');
-      stack.add(addConstantString(backend.namer.operatorIs(element)));
-    } else if (name == 'JS_CURRENT_ISOLATE') {
-      handleForeignJsCurrentIsolate(node);
-    } else if (name == 'JS_GET_NAME') {
-      handleForeignJsGetName(node);
-    } else if (name == 'JS_EMBEDDED_GLOBAL') {
-      handleForeignJsEmbeddedGlobal(node);
-    } else if (name == 'JS_GET_FLAG') {
-      handleForeingJsGetFlag(node);
-    } else if (name == 'JS_EFFECT') {
-      stack.add(graph.addConstantNull(compiler));
-    } else if (name == 'JS_INTERCEPTOR_CONSTANT') {
-      handleJsInterceptorConstant(node);
-    } else if (name == 'JS_STRING_CONCAT') {
-      handleJsStringConcat(node);
-    } else {
-      throw "Unknown foreign: ${selector}";
-    }
-  }
-
-  visitForeignGetter(ast.Send node) {
-    Element element = elements[node];
-    // Until now we only handle these as getters.
-    invariant(node, element.isDeferredLoaderGetter);
-    FunctionElement deferredLoader = element;
-    Element loadFunction = compiler.loadLibraryFunction;
-    PrefixElement prefixElement = deferredLoader.enclosingElement;
-    String loadId = compiler.deferredLoadTask
-        .importDeferName[prefixElement.deferredImport];
-    var inputs = [graph.addConstantString(
-        new ast.DartString.literal(loadId), compiler)];
-    push(new HInvokeStatic(loadFunction, inputs, backend.nonNullType,
-                           targetCanThrow: false));
-  }
-
-  generateSuperNoSuchMethodSend(ast.Send node,
-                                Selector selector,
-                                List<HInstruction> arguments) {
-    String name = selector.name;
-
-    ClassElement cls = currentNonClosureClass;
-    Element element = cls.lookupSuperMember(Compiler.NO_SUCH_METHOD);
-    if (compiler.enabledInvokeOn
-        && element.enclosingElement.declaration != compiler.objectClass) {
-      // Register the call as dynamic if [noSuchMethod] on the super
-      // class is _not_ the default implementation from [Object], in
-      // case the [noSuchMethod] implementation calls
-      // [JSInvocationMirror._invokeOn].
-      registry.registerSelectorUse(selector.asUntyped);
-    }
-    String publicName = name;
-    if (selector.isSetter) publicName += '=';
-
-    ConstantValue nameConstant = constantSystem.createString(
-        new ast.DartString.literal(publicName));
-
-    String internalName = backend.namer.invocationName(selector);
-    ConstantValue internalNameConstant =
-        constantSystem.createString(new ast.DartString.literal(internalName));
-
-    Element createInvocationMirror = backend.getCreateInvocationMirror();
-    var argumentsInstruction = buildLiteralList(arguments);
-    add(argumentsInstruction);
-
-    var argumentNames = new List<HInstruction>();
-    for (String argumentName in selector.namedArguments) {
-      ConstantValue argumentNameConstant =
-          constantSystem.createString(new ast.DartString.literal(argumentName));
-      argumentNames.add(graph.addConstant(argumentNameConstant, compiler));
-    }
-    var argumentNamesInstruction = buildLiteralList(argumentNames);
-    add(argumentNamesInstruction);
-
-    ConstantValue kindConstant =
-        constantSystem.createInt(selector.invocationMirrorKind);
-
-    pushInvokeStatic(null,
-                     createInvocationMirror,
-                     [graph.addConstant(nameConstant, compiler),
-                      graph.addConstant(internalNameConstant, compiler),
-                      graph.addConstant(kindConstant, compiler),
-                      argumentsInstruction,
-                      argumentNamesInstruction],
-                      backend.dynamicType);
-
-    var inputs = <HInstruction>[pop()];
-    push(buildInvokeSuper(compiler.noSuchMethodSelector, element, inputs));
-  }
-
-  visitSuperSend(ast.Send node) {
-    Selector selector = elements.getSelector(node);
-    Element element = elements[node];
-    if (Elements.isUnresolved(element)) {
-      List<HInstruction> arguments = <HInstruction>[];
-      if (!node.isPropertyAccess) {
-        addGenericSendArgumentsToList(node.arguments, arguments);
-      }
-      return generateSuperNoSuchMethodSend(node, selector, arguments);
-    }
-    List<HInstruction> inputs = <HInstruction>[];
-    if (node.isPropertyAccess) {
-      push(buildInvokeSuper(selector, element, inputs));
-    } else if (element.isFunction || element.isGenerativeConstructor) {
-      if (selector.applies(element, compiler.world)) {
-        // TODO(5347): Try to avoid the need for calling [implementation] before
-        // calling [addStaticSendArgumentsToList].
-        FunctionElement function = element.implementation;
-        bool succeeded = addStaticSendArgumentsToList(selector, node.arguments,
-                                                      function, inputs);
-        assert(succeeded);
-        push(buildInvokeSuper(selector, element, inputs));
-      } else if (element.isGenerativeConstructor) {
-        generateWrongArgumentCountError(node, element, node.arguments);
-      } else {
-        addGenericSendArgumentsToList(node.arguments, inputs);
-        generateSuperNoSuchMethodSend(node, selector, inputs);
-      }
-    } else {
-      HInstruction target = buildInvokeSuper(selector, element, inputs);
-      add(target);
-      inputs = <HInstruction>[target];
-      addDynamicSendArgumentsToList(node, inputs);
-      Selector closureSelector = new Selector.callClosureFrom(selector);
-      push(new HInvokeClosure(closureSelector, inputs, backend.dynamicType));
-    }
-  }
-
-  bool needsSubstitutionForTypeVariableAccess(ClassElement cls) {
-    ClassWorld classWorld = compiler.world;
-    if (classWorld.isUsedAsMixin(cls)) return true;
-
-    Iterable<ClassElement> subclasses = compiler.world.strictSubclassesOf(cls);
-    return subclasses.any((ClassElement subclass) {
-      return !rti.isTrivialSubstitution(subclass, cls);
-    });
-  }
-
-  /**
-   * Generate code to extract the type arguments from the object, substitute
-   * them as an instance of the type we are testing against (if necessary), and
-   * extract the type argument by the index of the variable in the list of type
-   * variables for that class.
-   */
-  HInstruction readTypeVariable(ClassElement cls,
-                                TypeVariableElement variable) {
-    assert(sourceElement.isInstanceMember);
-
-    HInstruction target = localsHandler.readThis();
-    HConstant index = graph.addConstantInt(
-        RuntimeTypes.getTypeVariableIndex(variable),
-        compiler);
-
-    if (needsSubstitutionForTypeVariableAccess(cls)) {
-      // TODO(ahe): Creating a string here is unfortunate. It is slow (due to
-      // string concatenation in the implementation), and may prevent
-      // segmentation of '$'.
-      String substitutionNameString = backend.namer.getNameForRti(cls);
-      HInstruction substitutionName = graph.addConstantString(
-          new ast.LiteralDartString(substitutionNameString), compiler);
-      pushInvokeStatic(null,
-                       backend.getGetRuntimeTypeArgument(),
-                       [target, substitutionName, index],
-                        backend.dynamicType);
-    } else {
-      pushInvokeStatic(null, backend.getGetTypeArgumentByIndex(),
-          [target, index],
-          backend.dynamicType);
-    }
-    return pop();
-  }
-
-  // TODO(karlklose): this is needed to avoid a bug where the resolved type is
-  // not stored on a type annotation in the closure translator. Remove when
-  // fixed.
-  bool hasDirectLocal(Local local) {
-    return !localsHandler.isAccessedDirectly(local) ||
-            localsHandler.directLocals[local] != null;
-  }
-
-  /**
-   * Helper to create an instruction that gets the value of a type variable.
-   */
-  HInstruction addTypeVariableReference(TypeVariableType type) {
-    assert(assertTypeInContext(type));
-    Element member = sourceElement;
-    bool isClosure = member.enclosingElement.isClosure;
-    if (isClosure) {
-      ClosureClassElement closureClass = member.enclosingElement;
-      member = closureClass.methodElement;
-      member = member.outermostEnclosingMemberOrTopLevel;
-    }
-    bool isInConstructorContext = member.isConstructor ||
-        member.isGenerativeConstructorBody;
-    Local typeVariableLocal = localsHandler.getTypeVariableAsLocal(type);
-    if (isClosure) {
-      if (member.isFactoryConstructor ||
-          (isInConstructorContext && hasDirectLocal(typeVariableLocal))) {
-        // The type variable is used from a closure in a factory constructor.
-        // The value of the type argument is stored as a local on the closure
-        // itself.
-        return localsHandler.readLocal(typeVariableLocal);
-      } else if (member.isFunction ||
-                 member.isGetter ||
-                 member.isSetter ||
-                 isInConstructorContext) {
-        // The type variable is stored on the "enclosing object" and needs to be
-        // accessed using the this-reference in the closure.
-        return readTypeVariable(member.enclosingClass, type.element);
-      } else {
-        assert(member.isField);
-        // The type variable is stored in a parameter of the method.
-        return localsHandler.readLocal(typeVariableLocal);
-      }
-    } else if (isInConstructorContext ||
-               // When [member] is a field, we can be either
-               // generating a checked setter or inlining its
-               // initializer in a constructor. An initializer is
-               // never built standalone, so [isBuildingFor] will
-               // always return true when seeing one.
-               (member.isField && !isBuildingFor(member))) {
-      // The type variable is stored in a parameter of the method.
-      return localsHandler.readLocal(typeVariableLocal);
-    } else if (member.isInstanceMember) {
-      // The type variable is stored on the object.
-      return readTypeVariable(member.enclosingClass,
-                              type.element);
-    } else {
-      // TODO(ngeoffray): Match the VM behavior and throw an
-      // exception at runtime.
-      compiler.internalError(type.element,
-          'Unimplemented unresolved type variable.');
-      return null;
-    }
-  }
-
-  HInstruction analyzeTypeArgument(DartType argument) {
-    assert(assertTypeInContext(argument));
-    if (argument.treatAsDynamic) {
-      // Represent [dynamic] as [null].
-      return graph.addConstantNull(compiler);
-    }
-
-    if (argument.isTypeVariable) {
-      return addTypeVariableReference(argument);
-    }
-
-    List<HInstruction> inputs = <HInstruction>[];
-
-    String template = rti.getTypeRepresentationWithHashes(argument, (variable) {
-      inputs.add(addTypeVariableReference(variable));
-    });
-
-    js.Template code = js.js.uncachedExpressionTemplate(template);
-    HInstruction result = createForeign(code, backend.stringType, inputs);
-    add(result);
-    return result;
-  }
-
-  HInstruction handleListConstructor(InterfaceType type,
-                                     ast.Node currentNode,
-                                     HInstruction newObject) {
-    if (!backend.classNeedsRti(type.element) || type.treatAsRaw) {
-      return newObject;
-    }
-    List<HInstruction> inputs = <HInstruction>[];
-    type = localsHandler.substInContext(type);
-    type.typeArguments.forEach((DartType argument) {
-      inputs.add(analyzeTypeArgument(argument));
-    });
-    // TODO(15489): Register at codegen.
-    registry.registerInstantiatedType(type);
-    return callSetRuntimeTypeInfo(type.element, inputs, newObject);
-  }
-
-  void copyRuntimeTypeInfo(HInstruction source, HInstruction target) {
-    Element copyHelper = backend.getCopyTypeArguments();
-    pushInvokeStatic(null, copyHelper, [source, target]);
-    pop();
-  }
-
-  HInstruction callSetRuntimeTypeInfo(ClassElement element,
-                                      List<HInstruction> rtiInputs,
-                                      HInstruction newObject) {
-    if (!backend.classNeedsRti(element) || element.typeVariables.isEmpty) {
-      return newObject;
-    }
-
-    HInstruction typeInfo = buildLiteralList(rtiInputs);
-    add(typeInfo);
-
-    // Set the runtime type information on the object.
-    Element typeInfoSetterElement = backend.getSetRuntimeTypeInfo();
-    pushInvokeStatic(
-        null,
-        typeInfoSetterElement,
-        <HInstruction>[newObject, typeInfo],
-        backend.dynamicType);
-
-    // The new object will now be referenced through the
-    // `setRuntimeTypeInfo` call. We therefore set the type of that
-    // instruction to be of the object's type.
-    assert(stack.last is HInvokeStatic || stack.last == newObject);
-    stack.last.instructionType = newObject.instructionType;
-    return pop();
-  }
-
-  handleNewSend(ast.NewExpression node) {
-    ast.Send send = node.send;
-    generateIsDeferredLoadedCheckIfNeeded(send);
-
-    bool isFixedList = false;
-    bool isFixedListConstructorCall =
-        Elements.isFixedListConstructorCall(elements[send], send, compiler);
-    bool isGrowableListConstructorCall =
-        Elements.isGrowableListConstructorCall(elements[send], send, compiler);
-
-    TypeMask computeType(element) {
-      Element originalElement = elements[send];
-      if (isFixedListConstructorCall
-          || Elements.isFilledListConstructorCall(
-                  originalElement, send, compiler)) {
-        isFixedList = true;
-        TypeMask inferred =
-            TypeMaskFactory.inferredForNode(sourceElement, send, compiler);
-        return inferred.containsAll(compiler.world)
-            ? backend.fixedArrayType
-            : inferred;
-      } else if (isGrowableListConstructorCall) {
-        TypeMask inferred =
-            TypeMaskFactory.inferredForNode(sourceElement, send, compiler);
-        return inferred.containsAll(compiler.world)
-            ? backend.extendableArrayType
-            : inferred;
-      } else if (Elements.isConstructorOfTypedArraySubclass(
-                    originalElement, compiler)) {
-        isFixedList = true;
-        TypeMask inferred =
-            TypeMaskFactory.inferredForNode(sourceElement, send, compiler);
-        ClassElement cls = element.enclosingClass;
-        assert(cls.thisType.element.isNative);
-        return inferred.containsAll(compiler.world)
-            ? new TypeMask.nonNullExact(cls.thisType.element, compiler.world)
-            : inferred;
-      } else if (element.isGenerativeConstructor) {
-        ClassElement cls = element.enclosingClass;
-        return new TypeMask.nonNullExact(cls.thisType.element, compiler.world);
-      } else {
-        return TypeMaskFactory.inferredReturnTypeForElement(
-            originalElement, compiler);
-      }
-    }
-
-    Element constructor = elements[send];
-    Selector selector = elements.getSelector(send);
-    ConstructorElement constructorDeclaration = constructor;
-    ConstructorElement constructorImplementation = constructor.implementation;
-    constructor = constructorImplementation.effectiveTarget;
-
-    final bool isSymbolConstructor =
-        constructorDeclaration == compiler.symbolConstructor;
-    final bool isJSArrayTypedConstructor =
-        constructorDeclaration == backend.jsArrayTypedConstructor;
-
-    if (isSymbolConstructor) {
-      constructor = compiler.symbolValidatedConstructor;
-      assert(invariant(send, constructor != null,
-                       message: 'Constructor Symbol.validated is missing'));
-      selector = compiler.symbolValidatedConstructorSelector;
-      assert(invariant(send, selector != null,
-                       message: 'Constructor Symbol.validated is missing'));
-    }
-
-    bool isRedirected = constructorDeclaration.isRedirectingFactory;
-    InterfaceType type = elements.getType(node);
-    InterfaceType expectedType =
-        constructorDeclaration.computeEffectiveTargetType(type);
-    expectedType = localsHandler.substInContext(expectedType);
-
-    if (checkTypeVariableBounds(node, type)) return;
-
-    var inputs = <HInstruction>[];
-    if (constructor.isGenerativeConstructor &&
-        Elements.isNativeOrExtendsNative(constructor.enclosingClass)) {
-      // Native class generative constructors take a pre-constructed object.
-      inputs.add(graph.addConstantNull(compiler));
-    }
-    // TODO(5347): Try to avoid the need for calling [implementation] before
-    // calling [addStaticSendArgumentsToList].
-    bool succeeded = addStaticSendArgumentsToList(selector, send.arguments,
-                                                  constructor.implementation,
-                                                  inputs);
-    if (!succeeded) {
-      generateWrongArgumentCountError(send, constructor, send.arguments);
-      return;
-    }
-
-    if (constructor.isFactoryConstructor &&
-        !expectedType.typeArguments.isEmpty) {
-      registry.registerFactoryWithTypeArguments();
-    }
-
-    TypeMask elementType = computeType(constructor);
-    if (isFixedListConstructorCall) {
-      if (!inputs[0].isNumber(compiler)) {
-        HTypeConversion conversion = new HTypeConversion(
-          null, HTypeConversion.ARGUMENT_TYPE_CHECK, backend.numType,
-          inputs[0], null);
-        add(conversion);
-        inputs[0] = conversion;
-      }
-      js.Template code = js.js.parseForeignJS('Array(#)');
-      var behavior = new native.NativeBehavior();
-      behavior.typesReturned.add(expectedType);
-      // The allocation can throw only if the given length is a double
-      // or negative.
-      bool canThrow = true;
-      if (inputs[0].isInteger(compiler) && inputs[0] is HConstant) {
-        var constant = inputs[0];
-        if (constant.constant.primitiveValue >= 0) canThrow = false;
-      }
-      HForeign foreign = new HForeign(
-          code, elementType, inputs, nativeBehavior: behavior,
-          canThrow: canThrow);
-      push(foreign);
-      TypesInferrer inferrer = compiler.typesTask.typesInferrer;
-      if (inferrer.isFixedArrayCheckedForGrowable(send)) {
-        js.Template code = js.js.parseForeignJS(r'#.fixed$length = init');
-        // We set the instruction as [canThrow] to avoid it being dead code.
-        // We need a finer grained side effect.
-        add(new HForeign(
-              code, backend.nullType, [stack.last], canThrow: true));
-      }
-    } else if (isGrowableListConstructorCall) {
-      push(buildLiteralList(<HInstruction>[]));
-      stack.last.instructionType = elementType;
-    } else {
-      ClassElement cls = constructor.enclosingClass;
-      if (cls.isAbstract && constructor.isGenerativeConstructor) {
-        generateAbstractClassInstantiationError(send, cls.name);
-        return;
-      }
-      potentiallyAddTypeArguments(inputs, cls, expectedType);
-
-      addInlinedInstantiation(expectedType);
-      pushInvokeStatic(node, constructor, inputs, elementType);
-      removeInlinedInstantiation(expectedType);
-    }
-    HInstruction newInstance = stack.last;
-    if (isFixedList) {
-      // Overwrite the element type, in case the allocation site has
-      // been inlined.
-      newInstance.instructionType = elementType;
-      JavaScriptItemCompilationContext context = work.compilationContext;
-      context.allocatedFixedLists.add(newInstance);
-    }
-
-    // The List constructor forwards to a Dart static method that does
-    // not know about the type argument. Therefore we special case
-    // this constructor to have the setRuntimeTypeInfo called where
-    // the 'new' is done.
-    if (backend.classNeedsRti(compiler.listClass) &&
-        (isFixedListConstructorCall || isGrowableListConstructorCall ||
-         isJSArrayTypedConstructor)) {
-      newInstance = handleListConstructor(type, send, pop());
-      stack.add(newInstance);
-    }
-
-    // Finally, if we called a redirecting factory constructor, check the type.
-    if (isRedirected) {
-      HInstruction checked = potentiallyCheckType(newInstance, type);
-      if (checked != newInstance) {
-        pop();
-        stack.add(checked);
-      }
-    }
-  }
-
-  void potentiallyAddTypeArguments(List<HInstruction> inputs, ClassElement cls,
-                                   InterfaceType expectedType) {
-    if (!backend.classNeedsRti(cls)) return;
-    assert(expectedType.typeArguments.isEmpty ||
-        cls.typeVariables.length == expectedType.typeArguments.length);
-    expectedType.typeArguments.forEach((DartType argument) {
-      inputs.add(analyzeTypeArgument(argument));
-    });
-  }
-
-  /// In checked mode checks the [type] of [node] to be well-bounded. The method
-  /// returns [:true:] if an error can be statically determined.
-  bool checkTypeVariableBounds(ast.NewExpression node, InterfaceType type) {
-    if (!compiler.enableTypeAssertions) return false;
-
-    Map<DartType, Set<DartType>> seenChecksMap =
-        new Map<DartType, Set<DartType>>();
-    bool definitelyFails = false;
-
-    addTypeVariableBoundCheck(GenericType instance,
-                              DartType typeArgument,
-                              TypeVariableType typeVariable,
-                              DartType bound) {
-      if (definitelyFails) return;
-
-      int subtypeRelation = compiler.types.computeSubtypeRelation(typeArgument, bound);
-      if (subtypeRelation == Types.IS_SUBTYPE) return;
-
-      String message =
-          "Can't create an instance of malbounded type '$type': "
-          "'${typeArgument}' is not a subtype of bound '${bound}' for "
-          "type variable '${typeVariable}' of type "
-          "${type == instance
-              ? "'${type.element.thisType}'"
-              : "'${instance.element.thisType}' on the supertype "
-                "'${instance}' of '${type}'"
-            }.";
-      if (subtypeRelation == Types.NOT_SUBTYPE) {
-        generateTypeError(node, message);
-        definitelyFails = true;
-        return;
-      } else if (subtypeRelation == Types.MAYBE_SUBTYPE) {
-        Set<DartType> seenChecks =
-            seenChecksMap.putIfAbsent(typeArgument, () => new Set<DartType>());
-        if (!seenChecks.contains(bound)) {
-          seenChecks.add(bound);
-          assertIsSubtype(node, typeArgument, bound, message);
-        }
-      }
-    }
-
-    compiler.types.checkTypeVariableBounds(type, addTypeVariableBoundCheck);
-    if (definitelyFails) {
-      return true;
-    }
-    for (InterfaceType supertype in type.element.allSupertypes) {
-      DartType instance = type.asInstanceOf(supertype.element);
-      compiler.types.checkTypeVariableBounds(instance,
-          addTypeVariableBoundCheck);
-      if (definitelyFails) {
-        return true;
-      }
-    }
-    return false;
-  }
-
-  visitAssert(node) {
-    if (!compiler.enableUserAssertions) {
-      stack.add(graph.addConstantNull(compiler));
-      return;
-    }
-    // TODO(johnniwinther): Don't handle assert like a regular static call.
-    // It breaks the selector name check since the assert helper method cannot
-    // be called `assert` and therefore does not match the selector like a
-    // regular method.
-    visitStaticSend(node);
-  }
-
-  visitStaticSend(ast.Send node) {
-    Selector selector = elements.getSelector(node);
-    Element element = elements[node];
-    if (elements.isAssert(node)) {
-      element = backend.assertMethod;
-    }
-    if (element.isForeign(backend) && element.isFunction) {
-      visitForeignSend(node);
-      return;
-    }
-    if (element.isErroneous) {
-      // An erroneous element indicates that the funciton could not be resolved
-      // (a warning has been issued).
-      generateThrowNoSuchMethod(node,
-                                noSuchMethodTargetSymbolString(element),
-                                argumentNodes: node.arguments);
-      return;
-    }
-    invariant(element, !element.isGenerativeConstructor);
-    generateIsDeferredLoadedCheckIfNeeded(node);
-    if (element.isFunction) {
-      var inputs = <HInstruction>[];
-      // TODO(5347): Try to avoid the need for calling [implementation] before
-      // calling [addStaticSendArgumentsToList].
-      bool succeeded = addStaticSendArgumentsToList(selector, node.arguments,
-                                                    element.implementation,
-                                                    inputs);
-      if (!succeeded) {
-        generateWrongArgumentCountError(node, element, node.arguments);
-        return;
-      }
-
-      if (element == compiler.identicalFunction) {
-        pushWithPosition(
-            new HIdentity(inputs[0], inputs[1], null, backend.boolType), node);
-        return;
-      }
-
-      pushInvokeStatic(node, element, inputs);
-    } else {
-      generateGetter(node, element);
-      List<HInstruction> inputs = <HInstruction>[pop()];
-      addDynamicSendArgumentsToList(node, inputs);
-      Selector closureSelector = new Selector.callClosureFrom(selector);
-      pushWithPosition(
-          new HInvokeClosure(closureSelector, inputs, backend.dynamicType),
-          node);
-    }
-  }
-
-  HConstant addConstantString(String string) {
-    ast.DartString dartString = new ast.DartString.literal(string);
-    ConstantValue constant = constantSystem.createString(dartString);
-    return graph.addConstant(constant, compiler);
-  }
-
-  visitTypePrefixSend(ast.Send node) {
-    compiler.internalError(node, "visitTypePrefixSend should not be called.");
-  }
-
-  visitTypeLiteralSend(ast.Send node) {
-    DartType type = elements.getTypeLiteralType(node);
-    if (type.isInterfaceType || type.isTypedef || type.isDynamic) {
-      // TODO(karlklose): add type representation
-      if (node.isCall) {
-        // The node itself is not a constant but we register the selector (the
-        // identifier that refers to the class/typedef) as a constant.
-        stack.add(addConstant(node.selector));
-      } else {
-        stack.add(addConstant(node));
-      }
-    } else if (type.isTypeVariable) {
-      type = localsHandler.substInContext(type);
-      HInstruction value = analyzeTypeArgument(type);
-      pushInvokeStatic(node,
-                       backend.getRuntimeTypeToString(),
-                       [value],
-                       backend.stringType);
-      pushInvokeStatic(node,
-                       backend.getCreateRuntimeType(),
-                       [pop()]);
-    } else {
-      internalError('unexpected type kind ${type.kind}', node: node);
-    }
-    if (node.isCall) {
-      // This send is of the form 'e(...)', where e is resolved to a type
-      // reference. We create a regular closure call on the result of the type
-      // reference instead of creating a NoSuchMethodError to avoid pulling it
-      // in if it is not used (e.g., in a try/catch).
-      HInstruction target = pop();
-      Selector selector = elements.getSelector(node);
-      List<HInstruction> inputs = <HInstruction>[target];
-      addDynamicSendArgumentsToList(node, inputs);
-      Selector closureSelector = new Selector.callClosureFrom(selector);
-      push(new HInvokeClosure(closureSelector, inputs, backend.dynamicType));
-    }
-  }
-
-  visitGetterSend(ast.Send node) {
-    generateIsDeferredLoadedCheckIfNeeded(node);
-    generateGetter(node, elements[node]);
-  }
-
-  // TODO(antonm): migrate rest of SsaFromAstMixin to internalError.
-  internalError(String reason, {ast.Node node}) {
-    compiler.internalError(node, reason);
-  }
-
-  void generateError(ast.Node node, String message, Element helper) {
-    HInstruction errorMessage = addConstantString(message);
-    pushInvokeStatic(node, helper, [errorMessage]);
-  }
-
-  void generateRuntimeError(ast.Node node, String message) {
-    generateError(node, message, backend.getThrowRuntimeError());
-  }
-
-  void generateTypeError(ast.Node node, String message) {
-    generateError(node, message, backend.getThrowTypeError());
-  }
-
-  void generateAbstractClassInstantiationError(ast.Node node, String message) {
-    generateError(node,
-                  message,
-                  backend.getThrowAbstractClassInstantiationError());
-  }
-
-  void generateThrowNoSuchMethod(ast.Node diagnosticNode,
-                                 String methodName,
-                                 {Link<ast.Node> argumentNodes,
-                                  List<HInstruction> argumentValues,
-                                  List<String> existingArguments}) {
-    Element helper = backend.getThrowNoSuchMethod();
-    ConstantValue receiverConstant =
-        constantSystem.createString(new ast.DartString.empty());
-    HInstruction receiver = graph.addConstant(receiverConstant, compiler);
-    ast.DartString dartString = new ast.DartString.literal(methodName);
-    ConstantValue nameConstant = constantSystem.createString(dartString);
-    HInstruction name = graph.addConstant(nameConstant, compiler);
-    if (argumentValues == null) {
-      argumentValues = <HInstruction>[];
-      argumentNodes.forEach((argumentNode) {
-        visit(argumentNode);
-        HInstruction value = pop();
-        argumentValues.add(value);
-      });
-    }
-    HInstruction arguments = buildLiteralList(argumentValues);
-    add(arguments);
-    HInstruction existingNamesList;
-    if (existingArguments != null) {
-      List<HInstruction> existingNames = <HInstruction>[];
-      for (String name in existingArguments) {
-        HInstruction nameConstant =
-            graph.addConstantString(new ast.DartString.literal(name), compiler);
-        existingNames.add(nameConstant);
-      }
-      existingNamesList = buildLiteralList(existingNames);
-      add(existingNamesList);
-    } else {
-      existingNamesList = graph.addConstantNull(compiler);
-    }
-    pushInvokeStatic(diagnosticNode,
-                     helper,
-                     [receiver, name, arguments, existingNamesList]);
-  }
-
-  /**
-   * Generate code to throw a [NoSuchMethodError] exception for calling a
-   * method with a wrong number of arguments or mismatching named optional
-   * arguments.
-   */
-  void generateWrongArgumentCountError(ast.Node diagnosticNode,
-                                       FunctionElement function,
-                                       Link<ast.Node> argumentNodes) {
-    List<String> existingArguments = <String>[];
-    FunctionSignature signature = function.functionSignature;
-    signature.forEachParameter((Element parameter) {
-      existingArguments.add(parameter.name);
-    });
-    generateThrowNoSuchMethod(diagnosticNode,
-                              function.name,
-                              argumentNodes: argumentNodes,
-                              existingArguments: existingArguments);
-  }
-
-  visitNewExpression(ast.NewExpression node) {
-    Element element = elements[node.send];
-    final bool isSymbolConstructor = element == compiler.symbolConstructor;
-    if (!Elements.isErroneousElement(element)) {
-      ConstructorElement function = element;
-      element = function.effectiveTarget;
-    }
-    if (Elements.isErroneousElement(element)) {
-      ErroneousElement error = element;
-      if (error.messageKind == MessageKind.CANNOT_FIND_CONSTRUCTOR) {
-        generateThrowNoSuchMethod(
-            node.send,
-            noSuchMethodTargetSymbolString(error, 'constructor'),
-            argumentNodes: node.send.arguments);
-      } else {
-        Message message = error.messageKind.message(error.messageArguments);
-        generateRuntimeError(node.send, message.toString());
-      }
-    } else if (node.isConst) {
-      stack.add(addConstant(node));
-      if (isSymbolConstructor) {
-        ConstructedConstantValue symbol = getConstantForNode(node);
-        StringConstantValue stringConstant = symbol.fields.single;
-        String nameString = stringConstant.toDartString().slowToString();
-        registry.registerConstSymbol(nameString);
-      }
-    } else {
-      handleNewSend(node);
-    }
-  }
-
-  void pushInvokeDynamic(ast.Node node,
-                         Selector selector,
-                         List<HInstruction> arguments,
-                         {ast.Node location}) {
-    if (location == null) location = node;
-
-    // We prefer to not inline certain operations on indexables,
-    // because the constant folder will handle them better and turn
-    // them into simpler instructions that allow further
-    // optimizations.
-    bool isOptimizableOperationOnIndexable(Selector selector, Element element) {
-      bool isLength = selector.isGetter
-          && selector.name == "length";
-      if (isLength || selector.isIndex) {
-        TypeMask type = new TypeMask.nonNullExact(
-            element.enclosingClass.declaration, compiler.world);
-        return type.satisfies(backend.jsIndexableClass, compiler.world);
-      } else if (selector.isIndexSet) {
-        TypeMask type = new TypeMask.nonNullExact(
-            element.enclosingClass.declaration, compiler.world);
-        return type.satisfies(backend.jsMutableIndexableClass, compiler.world);
-      } else {
-        return false;
-      }
-    }
-
-    bool isOptimizableOperation(Selector selector, Element element) {
-      ClassElement cls = element.enclosingClass;
-      if (isOptimizableOperationOnIndexable(selector, element)) return true;
-      if (!backend.interceptedClasses.contains(cls)) return false;
-      if (selector.isOperator) return true;
-      if (selector.isSetter) return true;
-      if (selector.isIndex) return true;
-      if (selector.isIndexSet) return true;
-      if (element == backend.jsArrayAdd
-          || element == backend.jsArrayRemoveLast
-          || element == backend.jsStringSplit) {
-        return true;
-      }
-      return false;
-    }
-
-    Element element = compiler.world.locateSingleElement(selector);
-    if (element != null
-        && !element.isField
-        && !(element.isGetter && selector.isCall)
-        && !(element.isFunction && selector.isGetter)
-        && !isOptimizableOperation(selector, element)) {
-      if (tryInlineMethod(element, selector, arguments, node)) {
-        return;
-      }
-    }
-
-    HInstruction receiver = arguments[0];
-    List<HInstruction> inputs = <HInstruction>[];
-    bool isIntercepted = backend.isInterceptedSelector(selector);
-    if (isIntercepted) {
-      inputs.add(invokeInterceptor(receiver));
-    }
-    inputs.addAll(arguments);
-    TypeMask type = TypeMaskFactory.inferredTypeForSelector(selector, compiler);
-    if (selector.isGetter) {
-      pushWithPosition(
-          new HInvokeDynamicGetter(selector, null, inputs, type),
-          location);
-    } else if (selector.isSetter) {
-      pushWithPosition(
-          new HInvokeDynamicSetter(selector, null, inputs, type),
-          location);
-    } else {
-      pushWithPosition(
-          new HInvokeDynamicMethod(selector, inputs, type, isIntercepted),
-          location);
-    }
-  }
-
-  void pushInvokeStatic(ast.Node location,
-                        Element element,
-                        List<HInstruction> arguments,
-                        [TypeMask type]) {
-    if (tryInlineMethod(element, null, arguments, location)) {
-      return;
-    }
-
-    if (type == null) {
-      type = TypeMaskFactory.inferredReturnTypeForElement(element, compiler);
-    }
-    bool targetCanThrow = !compiler.world.getCannotThrow(element);
-    // TODO(5346): Try to avoid the need for calling [declaration] before
-    // creating an [HInvokeStatic].
-    HInvokeStatic instruction = new HInvokeStatic(
-        element.declaration, arguments, type, targetCanThrow: targetCanThrow);
-    if (!currentInlinedInstantiations.isEmpty) {
-      instruction.instantiatedTypes = new List<DartType>.from(
-          currentInlinedInstantiations);
-    }
-    instruction.sideEffects = compiler.world.getSideEffectsOfElement(element);
-    if (location == null) {
-      push(instruction);
-    } else {
-      pushWithPosition(instruction, location);
-    }
-  }
-
-  HInstruction buildInvokeSuper(Selector selector,
-                                Element element,
-                                List<HInstruction> arguments) {
-    HInstruction receiver = localsHandler.readThis();
-    // TODO(5346): Try to avoid the need for calling [declaration] before
-    // creating an [HStatic].
-    List<HInstruction> inputs = <HInstruction>[];
-    if (backend.isInterceptedSelector(selector) &&
-        // Fields don't need an interceptor; consider generating HFieldGet/Set
-        // instead.
-        element.kind != ElementKind.FIELD) {
-      inputs.add(invokeInterceptor(receiver));
-    }
-    inputs.add(receiver);
-    inputs.addAll(arguments);
-    TypeMask type;
-    if (!element.isGetter && selector.isGetter) {
-      type = TypeMaskFactory.inferredTypeForElement(element, compiler);
-    } else {
-      type = TypeMaskFactory.inferredReturnTypeForElement(element, compiler);
-    }
-    HInstruction instruction = new HInvokeSuper(
-        element,
-        currentNonClosureClass,
-        selector,
-        inputs,
-        type,
-        isSetter: selector.isSetter || selector.isIndexSet);
-    instruction.sideEffects = compiler.world.getSideEffectsOfSelector(selector);
-    return instruction;
-  }
-
-  void handleComplexOperatorSend(ast.SendSet node,
-                                 HInstruction receiver,
-                                 Link<ast.Node> arguments) {
-    HInstruction rhs;
-    if (node.isPrefix || node.isPostfix) {
-      rhs = graph.addConstantInt(1, compiler);
-    } else {
-      visit(arguments.head);
-      assert(arguments.tail.isEmpty);
-      rhs = pop();
-    }
-    visitBinary(receiver, node.assignmentOperator, rhs,
-                elements.getOperatorSelectorInComplexSendSet(node), node);
-  }
-
-  visitSendSet(ast.SendSet node) {
-    generateIsDeferredLoadedCheckIfNeeded(node);
-    Element element = elements[node];
-    if (!Elements.isUnresolved(element) && element.impliesType) {
-      ast.Identifier selector = node.selector;
-      generateThrowNoSuchMethod(node, selector.source,
-                                argumentNodes: node.arguments);
-      return;
-    }
-    ast.Operator op = node.assignmentOperator;
-    if (node.isSuperCall) {
-      HInstruction result;
-      List<HInstruction> setterInputs = <HInstruction>[];
-      if (identical(node.assignmentOperator.source, '=')) {
-        addDynamicSendArgumentsToList(node, setterInputs);
-        result = setterInputs.last;
-      } else {
-        Element getter = elements[node.selector];
-        List<HInstruction> getterInputs = <HInstruction>[];
-        Link<ast.Node> arguments = node.arguments;
-        if (node.isIndex) {
-          // If node is of the from [:super.foo[0] += 2:], the send has
-          // two arguments: the index and the left hand side. We get
-          // the index and add it as input of the getter and the
-          // setter.
-          visit(arguments.head);
-          arguments = arguments.tail;
-          HInstruction index = pop();
-          getterInputs.add(index);
-          setterInputs.add(index);
-        }
-        HInstruction getterInstruction;
-        Selector getterSelector =
-            elements.getGetterSelectorInComplexSendSet(node);
-        if (Elements.isUnresolved(getter)) {
-          generateSuperNoSuchMethodSend(
-              node,
-              getterSelector,
-              getterInputs);
-          getterInstruction = pop();
-        } else {
-          getterInstruction = buildInvokeSuper(
-              getterSelector, getter, getterInputs);
-          add(getterInstruction);
-        }
-        handleComplexOperatorSend(node, getterInstruction, arguments);
-        setterInputs.add(pop());
-
-        if (node.isPostfix) {
-          result = getterInstruction;
-        } else {
-          result = setterInputs.last;
-        }
-      }
-      Selector setterSelector = elements.getSelector(node);
-      if (Elements.isUnresolved(element)
-          || !setterSelector.applies(element, compiler.world)) {
-        generateSuperNoSuchMethodSend(
-            node, setterSelector, setterInputs);
-        pop();
-      } else {
-        add(buildInvokeSuper(setterSelector, element, setterInputs));
-      }
-      stack.add(result);
-    } else if (node.isIndex) {
-      if ("=" == op.source) {
-        visitDynamicSend(node);
-      } else {
-        visit(node.receiver);
-        HInstruction receiver = pop();
-        Link<ast.Node> arguments = node.arguments;
-        HInstruction index;
-        if (node.isIndex) {
-          visit(arguments.head);
-          arguments = arguments.tail;
-          index = pop();
-        }
-
-        pushInvokeDynamic(
-            node,
-            elements.getGetterSelectorInComplexSendSet(node),
-            [receiver, index]);
-        HInstruction getterInstruction = pop();
-
-        handleComplexOperatorSend(node, getterInstruction, arguments);
-        HInstruction value = pop();
-
-        pushInvokeDynamic(
-            node, elements.getSelector(node), [receiver, index, value]);
-        pop();
-
-        if (node.isPostfix) {
-          stack.add(getterInstruction);
-        } else {
-          stack.add(value);
-        }
-      }
-    } else if ("=" == op.source) {
-      Link<ast.Node> link = node.arguments;
-      assert(!link.isEmpty && link.tail.isEmpty);
-      if (Elements.isInstanceSend(node, elements)) {
-        HInstruction receiver = generateInstanceSendReceiver(node);
-        visit(link.head);
-        generateInstanceSetterWithCompiledReceiver(node, receiver, pop());
-      } else {
-        visit(link.head);
-        generateNonInstanceSetter(node, element, pop());
-      }
-    } else if (identical(op.source, "is")) {
-      compiler.internalError(op, "is-operator as SendSet.");
-    } else {
-      assert("++" == op.source || "--" == op.source ||
-             node.assignmentOperator.source.endsWith("="));
-
-      // [receiver] is only used if the node is an instance send.
-      HInstruction receiver = null;
-      Element getter = elements[node.selector];
-
-      if (!Elements.isUnresolved(getter) && getter.impliesType) {
-        ast.Identifier selector = node.selector;
-        generateThrowNoSuchMethod(node, selector.source,
-                                  argumentNodes: node.arguments);
-        return;
-      } else if (Elements.isInstanceSend(node, elements)) {
-        receiver = generateInstanceSendReceiver(node);
-        generateInstanceGetterWithCompiledReceiver(
-            node, elements.getGetterSelectorInComplexSendSet(node), receiver);
-      } else {
-        generateGetter(node, getter);
-      }
-      HInstruction getterInstruction = pop();
-      handleComplexOperatorSend(node, getterInstruction, node.arguments);
-      HInstruction value = pop();
-      assert(value != null);
-      if (Elements.isInstanceSend(node, elements)) {
-        assert(receiver != null);
-        generateInstanceSetterWithCompiledReceiver(node, receiver, value);
-      } else {
-        assert(receiver == null);
-        generateNonInstanceSetter(node, element, value);
-      }
-      if (node.isPostfix) {
-        pop();
-        stack.add(getterInstruction);
-      }
-    }
-  }
-
-  void visitLiteralInt(ast.LiteralInt node) {
-    stack.add(graph.addConstantInt(node.value, compiler));
-  }
-
-  void visitLiteralDouble(ast.LiteralDouble node) {
-    stack.add(graph.addConstantDouble(node.value, compiler));
-  }
-
-  void visitLiteralBool(ast.LiteralBool node) {
-    stack.add(graph.addConstantBool(node.value, compiler));
-  }
-
-  void visitLiteralString(ast.LiteralString node) {
-    stack.add(graph.addConstantString(node.dartString, compiler));
-  }
-
-  void visitLiteralSymbol(ast.LiteralSymbol node) {
-    stack.add(addConstant(node));
-    registry.registerConstSymbol(node.slowNameString);
-  }
-
-  void visitStringJuxtaposition(ast.StringJuxtaposition node) {
-    if (!node.isInterpolation) {
-      // This is a simple string with no interpolations.
-      stack.add(graph.addConstantString(node.dartString, compiler));
-      return;
-    }
-    StringBuilderVisitor stringBuilder = new StringBuilderVisitor(this, node);
-    stringBuilder.visit(node);
-    stack.add(stringBuilder.result);
-  }
-
-  void visitLiteralNull(ast.LiteralNull node) {
-    stack.add(graph.addConstantNull(compiler));
-  }
-
-  visitNodeList(ast.NodeList node) {
-    for (Link<ast.Node> link = node.nodes; !link.isEmpty; link = link.tail) {
-      if (isAborted()) {
-        compiler.reportWarning(link.head,
-            MessageKind.GENERIC, {'text': 'dead code'});
-      } else {
-        visit(link.head);
-      }
-    }
-  }
-
-  void visitParenthesizedExpression(ast.ParenthesizedExpression node) {
-    visit(node.expression);
-  }
-
-  visitOperator(ast.Operator node) {
-    // Operators are intercepted in their surrounding Send nodes.
-    compiler.internalError(node,
-        'SsaBuilder.visitOperator should not be called.');
-  }
-
-  visitCascade(ast.Cascade node) {
-    visit(node.expression);
-    // Remove the result and reveal the duplicated receiver on the stack.
-    pop();
-  }
-
-  visitCascadeReceiver(ast.CascadeReceiver node) {
-    visit(node.expression);
-    dup();
-  }
-
-  void handleInTryStatement() {
-    if (!inTryStatement) return;
-    HBasicBlock block = close(new HExitTry());
-    HBasicBlock newBlock = graph.addNewBlock();
-    block.addSuccessor(newBlock);
-    open(newBlock);
-  }
-
-  visitRethrow(ast.Rethrow node) {
-    HInstruction exception = rethrowableException;
-    if (exception == null) {
-      exception = graph.addConstantNull(compiler);
-      compiler.internalError(node,
-          'rethrowableException should not be null.');
-    }
-    handleInTryStatement();
-    closeAndGotoExit(new HThrow(exception, isRethrow: true));
-  }
-
-  visitRedirectingFactoryBody(ast.RedirectingFactoryBody node) {
-    ConstructorElement targetConstructor =
-        elements.getRedirectingTargetConstructor(node).implementation;
-    ConstructorElement redirectingConstructor = sourceElement.implementation;
-    List<HInstruction> inputs = <HInstruction>[];
-    FunctionSignature targetSignature = targetConstructor.functionSignature;
-    FunctionSignature redirectingSignature =
-        redirectingConstructor.functionSignature;
-    redirectingSignature.forEachRequiredParameter((ParameterElement element) {
-      inputs.add(localsHandler.readLocal(element));
-    });
-    List<Element> targetOptionals =
-        targetSignature.orderedOptionalParameters;
-    List<Element> redirectingOptionals =
-        redirectingSignature.orderedOptionalParameters;
-    int i = 0;
-    for (; i < redirectingOptionals.length; i++) {
-      ParameterElement parameter = redirectingOptionals[i];
-      inputs.add(localsHandler.readLocal(parameter));
-    }
-    for (; i < targetOptionals.length; i++) {
-      inputs.add(handleConstantForOptionalParameter(targetOptionals[i]));
-    }
-    ClassElement targetClass = targetConstructor.enclosingClass;
-    if (backend.classNeedsRti(targetClass)) {
-      ClassElement cls = redirectingConstructor.enclosingClass;
-      InterfaceType targetType =
-          redirectingConstructor.computeEffectiveTargetType(cls.thisType);
-      targetType = localsHandler.substInContext(targetType);
-      targetType.typeArguments.forEach((DartType argument) {
-        inputs.add(analyzeTypeArgument(argument));
-      });
-    }
-    pushInvokeStatic(node, targetConstructor, inputs);
-    HInstruction value = pop();
-    emitReturn(value, node);
-  }
-
-  visitReturn(ast.Return node) {
-    if (identical(node.beginToken.stringValue, 'native')) {
-      native.handleSsaNative(this, node.expression);
-      return;
-    }
-    HInstruction value;
-    if (node.expression == null) {
-      value = graph.addConstantNull(compiler);
-    } else {
-      visit(node.expression);
-      value = pop();
-      value = potentiallyCheckType(value, returnType);
-    }
-
-    handleInTryStatement();
-    emitReturn(value, node);
-  }
-
-  visitThrow(ast.Throw node) {
-    visitThrowExpression(node.expression);
-    if (isReachable) {
-      handleInTryStatement();
-      push(new HThrowExpression(pop()));
-      isReachable = false;
-    }
-  }
-
-  visitYield(ast.Yield node) {
-    // Dummy implementation.
-    visit(node.expression);
-    pop();
-  }
-
-  visitAwait(ast.Await node) {
-    // Dummy implementation.
-    visit(node.expression);
-  }
-
-  visitTypeAnnotation(ast.TypeAnnotation node) {
-    compiler.internalError(node,
-        'Visiting type annotation in SSA builder.');
-  }
-
-  visitVariableDefinitions(ast.VariableDefinitions node) {
-    assert(isReachable);
-    for (Link<ast.Node> link = node.definitions.nodes;
-         !link.isEmpty;
-         link = link.tail) {
-      ast.Node definition = link.head;
-      if (definition is ast.Identifier) {
-        HInstruction initialValue = graph.addConstantNull(compiler);
-        LocalElement local = elements[definition];
-        localsHandler.updateLocal(local, initialValue);
-      } else {
-        assert(definition is ast.SendSet);
-        visitSendSet(definition);
-        pop();  // Discard value.
-      }
-    }
-  }
-
-  HInstruction setRtiIfNeeded(HInstruction object, ast.Node node) {
-    InterfaceType type = localsHandler.substInContext(elements.getType(node));
-    if (!backend.classNeedsRti(type.element) || type.treatAsRaw) {
-      return object;
-    }
-    List<HInstruction> arguments = <HInstruction>[];
-    for (DartType argument in type.typeArguments) {
-      arguments.add(analyzeTypeArgument(argument));
-    }
-    // TODO(15489): Register at codegen.
-    registry.registerInstantiatedType(type);
-    return callSetRuntimeTypeInfo(type.element, arguments, object);
-  }
-
-  visitLiteralList(ast.LiteralList node) {
-    HInstruction instruction;
-
-    if (node.isConst) {
-      instruction = addConstant(node);
-    } else {
-      List<HInstruction> inputs = <HInstruction>[];
-      for (Link<ast.Node> link = node.elements.nodes;
-           !link.isEmpty;
-           link = link.tail) {
-        visit(link.head);
-        inputs.add(pop());
-      }
-      instruction = buildLiteralList(inputs);
-      add(instruction);
-      instruction = setRtiIfNeeded(instruction, node);
-    }
-
-    TypeMask type =
-        TypeMaskFactory.inferredForNode(sourceElement, node, compiler);
-    if (!type.containsAll(compiler.world)) instruction.instructionType = type;
-    stack.add(instruction);
-  }
-
-  visitConditional(ast.Conditional node) {
-    SsaBranchBuilder brancher = new SsaBranchBuilder(this, node);
-    brancher.handleConditional(() => visit(node.condition),
-                               () => visit(node.thenExpression),
-                               () => visit(node.elseExpression));
-  }
-
-  visitStringInterpolation(ast.StringInterpolation node) {
-    StringBuilderVisitor stringBuilder = new StringBuilderVisitor(this, node);
-    stringBuilder.visit(node);
-    stack.add(stringBuilder.result);
-  }
-
-  visitStringInterpolationPart(ast.StringInterpolationPart node) {
-    // The parts are iterated in visitStringInterpolation.
-    compiler.internalError(node,
-      'SsaBuilder.visitStringInterpolation should not be called.');
-  }
-
-  visitEmptyStatement(ast.EmptyStatement node) {
-    // Do nothing, empty statement.
-  }
-
-  visitModifiers(ast.Modifiers node) {
-    compiler.unimplemented(node, 'SsaFromAstMixin.visitModifiers.');
-  }
-
-  visitBreakStatement(ast.BreakStatement node) {
-    assert(!isAborted());
-    handleInTryStatement();
-    JumpTarget target = elements.getTargetOf(node);
-    assert(target != null);
-    JumpHandler handler = jumpTargets[target];
-    assert(handler != null);
-    if (node.target == null) {
-      handler.generateBreak();
-    } else {
-      LabelDefinition label = elements.getTargetLabel(node);
-      handler.generateBreak(label);
-    }
-  }
-
-  visitContinueStatement(ast.ContinueStatement node) {
-    handleInTryStatement();
-    JumpTarget target = elements.getTargetOf(node);
-    assert(target != null);
-    JumpHandler handler = jumpTargets[target];
-    assert(handler != null);
-    if (node.target == null) {
-      handler.generateContinue();
-    } else {
-      LabelDefinition label = elements.getTargetLabel(node);
-      assert(label != null);
-      handler.generateContinue(label);
-    }
-  }
-
-  /**
-   * Creates a [JumpHandler] for a statement. The node must be a jump
-   * target. If there are no breaks or continues targeting the statement,
-   * a special "null handler" is returned.
-   *
-   * [isLoopJump] is [:true:] when the jump handler is for a loop. This is used
-   * to distinguish the synthetized loop created for a switch statement with
-   * continue statements from simple switch statements.
-   */
-  JumpHandler createJumpHandler(ast.Statement node, {bool isLoopJump}) {
-    JumpTarget element = elements.getTargetDefinition(node);
-    if (element == null || !identical(element.statement, node)) {
-      // No breaks or continues to this node.
-      return new NullJumpHandler(compiler);
-    }
-    if (isLoopJump && node is ast.SwitchStatement) {
-      // Create a special jump handler for loops created for switch statements
-      // with continue statements.
-      return new SwitchCaseJumpHandler(this, element, node);
-    }
-    return new JumpHandler(this, element);
-  }
-
-  visitForIn(ast.ForIn node) {
-    // Generate a structure equivalent to:
-    //   Iterator<E> $iter = <iterable>.iterator;
-    //   while ($iter.moveNext()) {
-    //     E <declaredIdentifier> = $iter.current;
-    //     <body>
-    //   }
-
-    // The iterator is shared between initializer, condition and body.
-    HInstruction iterator;
-    void buildInitializer() {
-      Selector selector = elements.getIteratorSelector(node);
-      visit(node.expression);
-      HInstruction receiver = pop();
-      pushInvokeDynamic(node, selector, [receiver]);
-      iterator = pop();
-    }
-    HInstruction buildCondition() {
-      Selector selector = elements.getMoveNextSelector(node);
-      pushInvokeDynamic(node, selector, [iterator]);
-      return popBoolified();
-    }
-    void buildBody() {
-      Selector call = elements.getCurrentSelector(node);
-      pushInvokeDynamic(node, call, [iterator]);
-
-      ast.Node identifier = node.declaredIdentifier;
-      Element variable = elements.getForInVariable(node);
-      Selector selector = elements.getSelector(identifier);
-
-      HInstruction value = pop();
-      if (identifier.asSend() != null
-          && Elements.isInstanceSend(identifier, elements)) {
-        HInstruction receiver = generateInstanceSendReceiver(identifier);
-        assert(receiver != null);
-        generateInstanceSetterWithCompiledReceiver(
-            null,
-            receiver,
-            value,
-            selector: selector,
-            location: identifier);
-      } else {
-        generateNonInstanceSetter(null, variable, value, location: identifier);
-      }
-      pop(); // Pop the value pushed by the setter call.
-
-      visit(node.body);
-    }
-    handleLoop(node, buildInitializer, buildCondition, () {}, buildBody);
-  }
-
-  visitLabel(ast.Label node) {
-    compiler.internalError(node, 'SsaFromAstMixin.visitLabel.');
-  }
-
-  visitLabeledStatement(ast.LabeledStatement node) {
-    ast.Statement body = node.statement;
-    if (body is ast.Loop
-        || body is ast.SwitchStatement
-        || Elements.isUnusedLabel(node, elements)) {
-      // Loops and switches handle their own labels.
-      visit(body);
-      return;
-    }
-    JumpTarget targetElement = elements.getTargetDefinition(body);
-    LocalsHandler beforeLocals = new LocalsHandler.from(localsHandler);
-    assert(targetElement.isBreakTarget);
-    JumpHandler handler = new JumpHandler(this, targetElement);
-    // Introduce a new basic block.
-    HBasicBlock entryBlock = openNewBlock();
-    visit(body);
-    SubGraph bodyGraph = new SubGraph(entryBlock, lastOpenedBlock);
-
-    HBasicBlock joinBlock = graph.addNewBlock();
-    List<LocalsHandler> breakHandlers = <LocalsHandler>[];
-    handler.forEachBreak((HBreak breakInstruction, LocalsHandler locals) {
-      breakInstruction.block.addSuccessor(joinBlock);
-      breakHandlers.add(locals);
-    });
-    bool hasBreak = breakHandlers.length > 0;
-    if (!isAborted()) {
-      goto(current, joinBlock);
-      breakHandlers.add(localsHandler);
-    }
-    open(joinBlock);
-    localsHandler = beforeLocals.mergeMultiple(breakHandlers, joinBlock);
-
-    if (hasBreak) {
-      // There was at least one reachable break, so the label is needed.
-      entryBlock.setBlockFlow(
-          new HLabeledBlockInformation(new HSubGraphBlockInformation(bodyGraph),
-                                       handler.labels()),
-          joinBlock);
-    }
-    handler.close();
-  }
-
-  visitLiteralMap(ast.LiteralMap node) {
-    if (node.isConst) {
-      stack.add(addConstant(node));
-      return;
-    }
-    List<HInstruction> listInputs = <HInstruction>[];
-    for (Link<ast.Node> link = node.entries.nodes;
-         !link.isEmpty;
-         link = link.tail) {
-      visit(link.head);
-      listInputs.add(pop());
-      listInputs.add(pop());
-    }
-
-    ConstructorElement constructor;
-    List<HInstruction> inputs = <HInstruction>[];
-
-    if (listInputs.isEmpty) {
-      constructor = backend.mapLiteralConstructorEmpty;
-    } else {
-      constructor = backend.mapLiteralConstructor;
-      HLiteralList keyValuePairs = buildLiteralList(listInputs);
-      add(keyValuePairs);
-      inputs.add(keyValuePairs);
-    }
-
-    assert(constructor.isFactoryConstructor);
-
-    ConstructorElement functionElement = constructor;
-    constructor = functionElement.effectiveTarget;
-
-    InterfaceType type = elements.getType(node);
-    InterfaceType expectedType =
-        functionElement.computeEffectiveTargetType(type);
-    expectedType = localsHandler.substInContext(expectedType);
-
-    if (constructor.isFactoryConstructor) {
-      registry.registerFactoryWithTypeArguments();
-    }
-
-    ClassElement cls = constructor.enclosingClass;
-
-    if (backend.classNeedsRti(cls)) {
-      List<DartType> typeVariable = cls.typeVariables;
-      expectedType.typeArguments.forEach((DartType argument) {
-        inputs.add(analyzeTypeArgument(argument));
-      });
-    }
-
-    // The instruction type will always be a subtype of the mapLiteralClass, but
-    // type inference might discover a more specific type, or find nothing (in
-    // dart2js unit tests).
-    TypeMask mapType =
-        new TypeMask.nonNullSubtype(backend.mapLiteralClass, compiler.world);
-    TypeMask returnTypeMask = TypeMaskFactory.inferredReturnTypeForElement(
-        constructor, compiler);
-    TypeMask instructionType =
-        mapType.intersection(returnTypeMask, compiler.world);
-
-    addInlinedInstantiation(expectedType);
-    pushInvokeStatic(node, constructor, inputs, instructionType);
-    removeInlinedInstantiation(expectedType);
-  }
-
-  visitLiteralMapEntry(ast.LiteralMapEntry node) {
-    visit(node.value);
-    visit(node.key);
-  }
-
-  visitNamedArgument(ast.NamedArgument node) {
-    visit(node.expression);
-  }
-
-  Map<ast.CaseMatch, ConstantValue> buildSwitchCaseConstants(
-      ast.SwitchStatement node) {
-
-    Map<ast.CaseMatch, ConstantValue> constants =
-        new Map<ast.CaseMatch, ConstantValue>();
-    for (ast.SwitchCase switchCase in node.cases) {
-      for (ast.Node labelOrCase in switchCase.labelsAndCases) {
-        if (labelOrCase is ast.CaseMatch) {
-          ast.CaseMatch match = labelOrCase;
-          ConstantValue constant = getConstantForNode(match.expression);
-          constants[labelOrCase] = constant;
-        }
-      }
-    }
-    return constants;
-  }
-
-  visitSwitchStatement(ast.SwitchStatement node) {
-    Map<ast.CaseMatch, ConstantValue> constants =
-        buildSwitchCaseConstants(node);
-
-    // The switch case indices must match those computed in
-    // [SwitchCaseJumpHandler].
-    bool hasContinue = false;
-    Map<ast.SwitchCase, int> caseIndex = new Map<ast.SwitchCase, int>();
-    int switchIndex = 1;
-    bool hasDefault = false;
-    for (ast.SwitchCase switchCase in node.cases) {
-      for (ast.Node labelOrCase in switchCase.labelsAndCases) {
-        ast.Node label = labelOrCase.asLabel();
-        if (label != null) {
-          LabelDefinition labelElement = elements.getLabelDefinition(label);
-          if (labelElement != null && labelElement.isContinueTarget) {
-            hasContinue = true;
-          }
-        }
-      }
-      if (switchCase.isDefaultCase) {
-        hasDefault = true;
-      }
-      caseIndex[switchCase] = switchIndex;
-      switchIndex++;
-    }
-    if (!hasContinue) {
-      // If the switch statement has no switch cases targeted by continue
-      // statements we encode the switch statement directly.
-      buildSimpleSwitchStatement(node, constants);
-    } else {
-      buildComplexSwitchStatement(node, constants, caseIndex, hasDefault);
-    }
-  }
-
-  /**
-   * Builds a simple switch statement which does not handle uses of continue
-   * statements to labeled switch cases.
-   */
-  void buildSimpleSwitchStatement(ast.SwitchStatement node,
-                                  Map<ast.CaseMatch, ConstantValue> constants) {
-    JumpHandler jumpHandler = createJumpHandler(node, isLoopJump: false);
-    HInstruction buildExpression() {
-      visit(node.expression);
-      return pop();
-    }
-    Iterable<ConstantValue> getConstants(ast.SwitchCase switchCase) {
-      List<ConstantValue> constantList = <ConstantValue>[];
-      for (ast.Node labelOrCase in switchCase.labelsAndCases) {
-        if (labelOrCase is ast.CaseMatch) {
-          constantList.add(constants[labelOrCase]);
-        }
-      }
-      return constantList;
-    }
-    bool isDefaultCase(ast.SwitchCase switchCase) {
-      return switchCase.isDefaultCase;
-    }
-    void buildSwitchCase(ast.SwitchCase node) {
-      visit(node.statements);
-    }
-    handleSwitch(node,
-                 jumpHandler,
-                 buildExpression,
-                 node.cases,
-                 getConstants,
-                 isDefaultCase,
-                 buildSwitchCase);
-    jumpHandler.close();
-  }
-
-  /**
-   * Builds a switch statement that can handle arbitrary uses of continue
-   * statements to labeled switch cases.
-   */
-  void buildComplexSwitchStatement(ast.SwitchStatement node,
-                                   Map<ast.CaseMatch, ConstantValue> constants,
-                                   Map<ast.SwitchCase, int> caseIndex,
-                                   bool hasDefault) {
-    // If the switch statement has switch cases targeted by continue
-    // statements we create the following encoding:
-    //
-    //   switch (e) {
-    //     l_1: case e0: s_1; break;
-    //     l_2: case e1: s_2; continue l_i;
-    //     ...
-    //     l_n: default: s_n; continue l_j;
-    //   }
-    //
-    // is encoded as
-    //
-    //   var target;
-    //   switch (e) {
-    //     case e1: target = 1; break;
-    //     case e2: target = 2; break;
-    //     ...
-    //     default: target = n; break;
-    //   }
-    //   l: while (true) {
-    //    switch (target) {
-    //       case 1: s_1; break l;
-    //       case 2: s_2; target = i; continue l;
-    //       ...
-    //       case n: s_n; target = j; continue l;
-    //     }
-    //   }
-
-    JumpTarget switchTarget = elements.getTargetDefinition(node);
-    HInstruction initialValue = graph.addConstantNull(compiler);
-    localsHandler.updateLocal(switchTarget, initialValue);
-
-    JumpHandler jumpHandler = createJumpHandler(node, isLoopJump: false);
-    var switchCases = node.cases;
-    if (!hasDefault) {
-      // Use [:null:] as the marker for a synthetic default clause.
-      // The synthetic default is added because otherwise, there would be no
-      // good place to give a default value to the local.
-      switchCases = node.cases.nodes.toList()..add(null);
-    }
-    HInstruction buildExpression() {
-      visit(node.expression);
-      return pop();
-    }
-    Iterable<ConstantValue> getConstants(ast.SwitchCase switchCase) {
-      List<ConstantValue> constantList = <ConstantValue>[];
-      if (switchCase != null) {
-        for (ast.Node labelOrCase in switchCase.labelsAndCases) {
-          if (labelOrCase is ast.CaseMatch) {
-            constantList.add(constants[labelOrCase]);
-          }
-        }
-      }
-      return constantList;
-    }
-    bool isDefaultCase(ast.SwitchCase switchCase) {
-      return switchCase == null || switchCase.isDefaultCase;
-    }
-    void buildSwitchCase(ast.SwitchCase switchCase) {
-      if (switchCase != null) {
-        // Generate 'target = i; break;' for switch case i.
-        int index = caseIndex[switchCase];
-        HInstruction value = graph.addConstantInt(index, compiler);
-        localsHandler.updateLocal(switchTarget, value);
-      } else {
-        // Generate synthetic default case 'target = null; break;'.
-        HInstruction value = graph.addConstantNull(compiler);
-        localsHandler.updateLocal(switchTarget, value);
-      }
-      jumpTargets[switchTarget].generateBreak();
-    }
-    handleSwitch(node,
-                 jumpHandler,
-                 buildExpression,
-                 switchCases,
-                 getConstants,
-                 isDefaultCase,
-                 buildSwitchCase);
-    jumpHandler.close();
-
-    HInstruction buildCondition() =>
-        graph.addConstantBool(true, compiler);
-
-    void buildSwitch() {
-      HInstruction buildExpression() {
-        return localsHandler.readLocal(switchTarget);
-      }
-      Iterable<ConstantValue> getConstants(ast.SwitchCase switchCase) {
-        return <ConstantValue>[constantSystem.createInt(caseIndex[switchCase])];
-      }
-      void buildSwitchCase(ast.SwitchCase switchCase) {
-        visit(switchCase.statements);
-        if (!isAborted()) {
-          // Ensure that we break the loop if the case falls through. (This
-          // is only possible for the last case.)
-          jumpTargets[switchTarget].generateBreak();
-        }
-      }
-      // Pass a [NullJumpHandler] because the target for the contained break
-      // is not the generated switch statement but instead the loop generated
-      // in the call to [handleLoop] below.
-      handleSwitch(node,
-                   new NullJumpHandler(compiler),
-                   buildExpression, node.cases, getConstants,
-                   (_) => false, // No case is default.
-                   buildSwitchCase);
-    }
-
-    void buildLoop() {
-      handleLoop(node,
-          () {},
-          buildCondition,
-          () {},
-          buildSwitch);
-    }
-
-    if (hasDefault) {
-      buildLoop();
-    } else {
-      // If the switch statement has no default case, surround the loop with
-      // a test of the target.
-      void buildCondition() {
-        js.Template code = js.js.parseForeignJS('#');
-        push(createForeign(code,
-                           backend.boolType,
-                           [localsHandler.readLocal(switchTarget)]));
-      }
-      handleIf(node, buildCondition, buildLoop, () => {});
-    }
-  }
-
-  /**
-   * Creates a switch statement.
-   *
-   * [jumpHandler] is the [JumpHandler] for the created switch statement.
-   * [buildExpression] creates the switch expression.
-   * [switchCases] must be either an [Iterable] of [ast.SwitchCase] nodes or
-   *   a [Link] or a [ast.NodeList] of [ast.SwitchCase] nodes.
-   * [getConstants] returns the set of constants for a switch case.
-   * [isDefaultCase] returns [:true:] if the provided switch case should be
-   *   considered default for the created switch statement.
-   * [buildSwitchCase] creates the statements for the switch case.
-   */
-  void handleSwitch(
-      ast.Node errorNode,
-      JumpHandler jumpHandler,
-      HInstruction buildExpression(),
-      var switchCases,
-      Iterable<ConstantValue> getConstants(ast.SwitchCase switchCase),
-      bool isDefaultCase(ast.SwitchCase switchCase),
-      void buildSwitchCase(ast.SwitchCase switchCase)) {
-
-    Map<ast.CaseMatch, ConstantValue> constants =
-        new Map<ast.CaseMatch, ConstantValue>();
-
-    HBasicBlock expressionStart = openNewBlock();
-    HInstruction expression = buildExpression();
-    if (switchCases.isEmpty) {
-      return;
-    }
-
-    HSwitch switchInstruction = new HSwitch(<HInstruction>[expression]);
-    HBasicBlock expressionEnd = close(switchInstruction);
-    LocalsHandler savedLocals = localsHandler;
-
-    List<HStatementInformation> statements = <HStatementInformation>[];
-    bool hasDefault = false;
-    Element getFallThroughErrorElement = backend.getFallThroughError();
-    HasNextIterator<ast.Node> caseIterator =
-        new HasNextIterator<ast.Node>(switchCases.iterator);
-    while (caseIterator.hasNext) {
-      ast.SwitchCase switchCase = caseIterator.next();
-      HBasicBlock block = graph.addNewBlock();
-      for (ConstantValue constant in getConstants(switchCase)) {
-        HConstant hConstant = graph.addConstant(constant, compiler);
-        switchInstruction.inputs.add(hConstant);
-        hConstant.usedBy.add(switchInstruction);
-        expressionEnd.addSuccessor(block);
-      }
-
-      if (isDefaultCase(switchCase)) {
-        // An HSwitch has n inputs and n+1 successors, the last being the
-        // default case.
-        expressionEnd.addSuccessor(block);
-        hasDefault = true;
-      }
-      open(block);
-      localsHandler = new LocalsHandler.from(savedLocals);
-      buildSwitchCase(switchCase);
-      if (!isAborted()) {
-        if (caseIterator.hasNext) {
-          pushInvokeStatic(switchCase, getFallThroughErrorElement, []);
-          HInstruction error = pop();
-          closeAndGotoExit(new HThrow(error));
-        } else if (!isDefaultCase(switchCase)) {
-          // If there is no default, we will add one later to avoid
-          // the critical edge. So we generate a break statement to make
-          // sure the last case does not fall through to the default case.
-          jumpHandler.generateBreak();
-        }
-      }
-      statements.add(
-          new HSubGraphBlockInformation(new SubGraph(block, lastOpenedBlock)));
-    }
-
-    // Add a join-block if necessary.
-    // We create [joinBlock] early, and then go through the cases that might
-    // want to jump to it. In each case, if we add [joinBlock] as a successor
-    // of another block, we also add an element to [caseHandlers] that is used
-    // to create the phis in [joinBlock].
-    // If we never jump to the join block, [caseHandlers] will stay empty, and
-    // the join block is never added to the graph.
-    HBasicBlock joinBlock = new HBasicBlock();
-    List<LocalsHandler> caseHandlers = <LocalsHandler>[];
-    jumpHandler.forEachBreak((HBreak instruction, LocalsHandler locals) {
-      instruction.block.addSuccessor(joinBlock);
-      caseHandlers.add(locals);
-    });
-    jumpHandler.forEachContinue((HContinue instruction, LocalsHandler locals) {
-      assert(invariant(errorNode, false,
-                       message: 'Continue cannot target a switch.'));
-    });
-    if (!isAborted()) {
-      current.close(new HGoto());
-      lastOpenedBlock.addSuccessor(joinBlock);
-      caseHandlers.add(localsHandler);
-    }
-    if (!hasDefault) {
-      // Always create a default case, to avoid a critical edge in the
-      // graph.
-      HBasicBlock defaultCase = addNewBlock();
-      expressionEnd.addSuccessor(defaultCase);
-      open(defaultCase);
-      close(new HGoto());
-      defaultCase.addSuccessor(joinBlock);
-      caseHandlers.add(savedLocals);
-      statements.add(new HSubGraphBlockInformation(new SubGraph(
-          defaultCase, defaultCase)));
-    }
-    assert(caseHandlers.length == joinBlock.predecessors.length);
-    if (caseHandlers.length != 0) {
-      graph.addBlock(joinBlock);
-      open(joinBlock);
-      if (caseHandlers.length == 1) {
-        localsHandler = caseHandlers[0];
-      } else {
-        localsHandler = savedLocals.mergeMultiple(caseHandlers, joinBlock);
-      }
-    } else {
-      // The joinblock is not used.
-      joinBlock = null;
-    }
-
-    HSubExpressionBlockInformation expressionInfo =
-        new HSubExpressionBlockInformation(new SubExpression(expressionStart,
-                                                             expressionEnd));
-    expressionStart.setBlockFlow(
-        new HSwitchBlockInformation(expressionInfo,
-                                    statements,
-                                    jumpHandler.target,
-                                    jumpHandler.labels()),
-        joinBlock);
-
-    jumpHandler.close();
-  }
-
-  visitSwitchCase(ast.SwitchCase node) {
-    compiler.internalError(node, 'SsaFromAstMixin.visitSwitchCase.');
-  }
-
-  visitCaseMatch(ast.CaseMatch node) {
-    compiler.internalError(node, 'SsaFromAstMixin.visitCaseMatch.');
-  }
-
-  visitTryStatement(ast.TryStatement node) {
-    // Save the current locals. The catch block and the finally block
-    // must not reuse the existing locals handler. None of the variables
-    // that have been defined in the body-block will be used, but for
-    // loops we will add (unnecessary) phis that will reference the body
-    // variables. This makes it look as if the variables were used
-    // in a non-dominated block.
-    LocalsHandler savedLocals = new LocalsHandler.from(localsHandler);
-    HBasicBlock enterBlock = openNewBlock();
-    HTry tryInstruction = new HTry();
-    close(tryInstruction);
-    bool oldInTryStatement = inTryStatement;
-    inTryStatement = true;
-
-    HBasicBlock startTryBlock;
-    HBasicBlock endTryBlock;
-    HBasicBlock startCatchBlock;
-    HBasicBlock endCatchBlock;
-    HBasicBlock startFinallyBlock;
-    HBasicBlock endFinallyBlock;
-
-    startTryBlock = graph.addNewBlock();
-    open(startTryBlock);
-    visit(node.tryBlock);
-    // We use a [HExitTry] instead of a [HGoto] for the try block
-    // because it will have multiple successors: the join block, and
-    // the catch or finally block.
-    if (!isAborted()) endTryBlock = close(new HExitTry());
-    SubGraph bodyGraph = new SubGraph(startTryBlock, lastOpenedBlock);
-    SubGraph catchGraph = null;
-    HLocalValue exception = null;
-
-    if (!node.catchBlocks.isEmpty) {
-      localsHandler = new LocalsHandler.from(savedLocals);
-      startCatchBlock = graph.addNewBlock();
-      open(startCatchBlock);
-      // Note that the name of this local is irrelevant.
-      SyntheticLocal local =
-          new SyntheticLocal('exception', localsHandler.executableContext);
-      exception = new HLocalValue(local, backend.nonNullType);
-      add(exception);
-      HInstruction oldRethrowableException = rethrowableException;
-      rethrowableException = exception;
-
-      pushInvokeStatic(node, backend.getExceptionUnwrapper(), [exception]);
-      HInvokeStatic unwrappedException = pop();
-      tryInstruction.exception = exception;
-      Link<ast.Node> link = node.catchBlocks.nodes;
-
-      void pushCondition(ast.CatchBlock catchBlock) {
-        if (catchBlock.onKeyword != null) {
-          DartType type = elements.getType(catchBlock.type);
-          if (type == null) {
-            compiler.internalError(catchBlock.type, 'On with no type.');
-          }
-          HInstruction condition =
-              buildIsNode(catchBlock.type, type, unwrappedException);
-          push(condition);
-        } else {
-          ast.VariableDefinitions declaration = catchBlock.formals.nodes.head;
-          HInstruction condition = null;
-          if (declaration.type == null) {
-            condition = graph.addConstantBool(true, compiler);
-            stack.add(condition);
-          } else {
-            // TODO(aprelev@gmail.com): Once old catch syntax is removed
-            // "if" condition above and this "else" branch should be deleted as
-            // type of declared variable won't matter for the catch
-            // condition.
-            DartType type = elements.getType(declaration.type);
-            if (type == null) {
-              compiler.internalError(catchBlock, 'Catch with unresolved type.');
-            }
-            condition = buildIsNode(declaration.type, type, unwrappedException);
-            push(condition);
-          }
-        }
-      }
-
-      void visitThen() {
-        ast.CatchBlock catchBlock = link.head;
-        link = link.tail;
-        if (catchBlock.exception != null) {
-          LocalVariableElement exceptionVariable =
-              elements[catchBlock.exception];
-          localsHandler.updateLocal(exceptionVariable,
-                                    unwrappedException);
-        }
-        ast.Node trace = catchBlock.trace;
-        if (trace != null) {
-          pushInvokeStatic(trace, backend.getTraceFromException(), [exception]);
-          HInstruction traceInstruction = pop();
-          LocalVariableElement traceVariable = elements[trace];
-          localsHandler.updateLocal(traceVariable, traceInstruction);
-        }
-        visit(catchBlock);
-      }
-
-      void visitElse() {
-        if (link.isEmpty) {
-          closeAndGotoExit(new HThrow(exception, isRethrow: true));
-        } else {
-          ast.CatchBlock newBlock = link.head;
-          handleIf(node,
-                   () { pushCondition(newBlock); },
-                   visitThen, visitElse);
-        }
-      }
-
-      ast.CatchBlock firstBlock = link.head;
-      handleIf(node, () { pushCondition(firstBlock); }, visitThen, visitElse);
-      if (!isAborted()) endCatchBlock = close(new HGoto());
-
-      rethrowableException = oldRethrowableException;
-      tryInstruction.catchBlock = startCatchBlock;
-      catchGraph = new SubGraph(startCatchBlock, lastOpenedBlock);
-    }
-
-    SubGraph finallyGraph = null;
-    if (node.finallyBlock != null) {
-      localsHandler = new LocalsHandler.from(savedLocals);
-      startFinallyBlock = graph.addNewBlock();
-      open(startFinallyBlock);
-      visit(node.finallyBlock);
-      if (!isAborted()) endFinallyBlock = close(new HGoto());
-      tryInstruction.finallyBlock = startFinallyBlock;
-      finallyGraph = new SubGraph(startFinallyBlock, lastOpenedBlock);
-    }
-
-    HBasicBlock exitBlock = graph.addNewBlock();
-
-    addOptionalSuccessor(b1, b2) { if (b2 != null) b1.addSuccessor(b2); }
-    addExitTrySuccessor(successor) {
-      if (successor == null) return;
-      // Iterate over all blocks created inside this try/catch, and
-      // attach successor information to blocks that end with
-      // [HExitTry].
-      for (int i = startTryBlock.id; i < successor.id; i++) {
-        HBasicBlock block = graph.blocks[i];
-        var last = block.last;
-        if (last is HExitTry) {
-          block.addSuccessor(successor);
-        }
-      }
-    }
-
-    // Setup all successors. The entry block that contains the [HTry]
-    // has 1) the body, 2) the catch, 3) the finally, and 4) the exit
-    // blocks as successors.
-    enterBlock.addSuccessor(startTryBlock);
-    addOptionalSuccessor(enterBlock, startCatchBlock);
-    addOptionalSuccessor(enterBlock, startFinallyBlock);
-    enterBlock.addSuccessor(exitBlock);
-
-    // The body has either the catch or the finally block as successor.
-    if (endTryBlock != null) {
-      assert(startCatchBlock != null || startFinallyBlock != null);
-      endTryBlock.addSuccessor(
-          startCatchBlock != null ? startCatchBlock : startFinallyBlock);
-      endTryBlock.addSuccessor(exitBlock);
-    }
-
-    // The catch block has either the finally or the exit block as
-    // successor.
-    if (endCatchBlock != null) {
-      endCatchBlock.addSuccessor(
-          startFinallyBlock != null ? startFinallyBlock : exitBlock);
-    }
-
-    // The finally block has the exit block as successor.
-    if (endFinallyBlock != null) {
-      endFinallyBlock.addSuccessor(exitBlock);
-    }
-
-    // If a block inside try/catch aborts (eg with a return statement),
-    // we explicitely mark this block a predecessor of the catch
-    // block and the finally block.
-    addExitTrySuccessor(startCatchBlock);
-    addExitTrySuccessor(startFinallyBlock);
-
-    // Use the locals handler not altered by the catch and finally
-    // blocks.
-    localsHandler = savedLocals;
-    open(exitBlock);
-    enterBlock.setBlockFlow(
-        new HTryBlockInformation(
-          wrapStatementGraph(bodyGraph),
-          exception,
-          wrapStatementGraph(catchGraph),
-          wrapStatementGraph(finallyGraph)),
-        exitBlock);
-    inTryStatement = oldInTryStatement;
-  }
-
-  visitCatchBlock(ast.CatchBlock node) {
-    visit(node.block);
-  }
-
-  visitTypedef(ast.Typedef node) {
-    compiler.unimplemented(node, 'SsaFromAstMixin.visitTypedef.');
-  }
-
-  visitTypeVariable(ast.TypeVariable node) {
-    compiler.internalError(node, 'SsaFromAstMixin.visitTypeVariable.');
-  }
-
-  /**
-   * This method is invoked before inlining the body of [function] into this
-   * [SsaBuilder].
-   */
-  void enterInlinedMethod(FunctionElement function,
-                          ast.Node _,
-                          List<HInstruction> compiledArguments) {
-    TypesInferrer inferrer = compiler.typesTask.typesInferrer;
-    AstInliningState state = new AstInliningState(
-        function, returnLocal, returnType, elements, stack, localsHandler,
-        inTryStatement,
-        allInlinedFunctionsCalledOnce && inferrer.isCalledOnce(function));
-    inliningStack.add(state);
-
-    // Setting up the state of the (AST) builder is performed even when the
-    // inlined function is in IR, because the irInliner uses the [returnElement]
-    // of the AST builder.
-    setupStateForInlining(function, compiledArguments);
-  }
-
-  void leaveInlinedMethod() {
-    HInstruction result = localsHandler.readLocal(returnLocal);
-    AstInliningState state = inliningStack.removeLast();
-    restoreState(state);
-    stack.add(result);
-  }
-
-  void doInline(FunctionElement function) {
-    visitInlinedFunction(function);
-  }
-
-  void emitReturn(HInstruction value, ast.Node node) {
-    if (inliningStack.isEmpty) {
-      closeAndGotoExit(attachPosition(new HReturn(value), node));
-    } else {
-      localsHandler.updateLocal(returnLocal, value);
-    }
-  }
-}
-
-/**
- * Visitor that handles generation of string literals (LiteralString,
- * StringInterpolation), and otherwise delegates to the given visitor for
- * non-literal subexpressions.
- */
-class StringBuilderVisitor extends ast.Visitor {
-  final SsaBuilder builder;
-  final ast.Node diagnosticNode;
-
-  /**
-   * The string value generated so far.
-   */
-  HInstruction result = null;
-
-  StringBuilderVisitor(this.builder, this.diagnosticNode);
-
-  Compiler get compiler => builder.compiler;
-
-  void visit(ast.Node node) {
-    node.accept(this);
-  }
-
-  visitNode(ast.Node node) {
-    builder.compiler.internalError(node, 'Unexpected node.');
-  }
-
-  void visitExpression(ast.Node node) {
-    node.accept(builder);
-    HInstruction expression = builder.pop();
-
-    // We want to use HStringify when:
-    //   1. The value is known to be a primitive type, because it might get
-    //      constant-folded and codegen has some tricks with JavaScript
-    //      conversions.
-    //   2. The value can be primitive, because the library stringifier has
-    //      fast-path code for most primitives.
-    if (expression.canBePrimitive(compiler)) {
-      append(stringify(node, expression));
-      return;
-    }
-
-    // If the `toString` method is guaranteed to return a string we can call it
-    // directly.
-    Selector selector =
-        new TypedSelector(expression.instructionType,
-            new Selector.call('toString', null, 0), compiler.world);
-    TypeMask type = TypeMaskFactory.inferredTypeForSelector(selector, compiler);
-    if (type.containsOnlyString(compiler.world)) {
-      builder.pushInvokeDynamic(node, selector, <HInstruction>[expression]);
-      append(builder.pop());
-      return;
-    }
-
-    append(stringify(node, expression));
-  }
-
-  void visitStringInterpolation(ast.StringInterpolation node) {
-    node.visitChildren(this);
-  }
-
-  void visitStringInterpolationPart(ast.StringInterpolationPart node) {
-    visit(node.expression);
-    visit(node.string);
-  }
-
-  void visitStringJuxtaposition(ast.StringJuxtaposition node) {
-    node.visitChildren(this);
-  }
-
-  void visitNodeList(ast.NodeList node) {
-     node.visitChildren(this);
-  }
-
-  void append(HInstruction expression) {
-    result = (result == null) ? expression : concat(result, expression);
-  }
-
-  HInstruction concat(HInstruction left, HInstruction right) {
-    HInstruction instruction = new HStringConcat(
-        left, right, diagnosticNode, builder.backend.stringType);
-    builder.add(instruction);
-    return instruction;
-  }
-
-  HInstruction stringify(ast.Node node, HInstruction expression) {
-    HInstruction instruction =
-        new HStringify(expression, node, builder.backend.stringType);
-    builder.add(instruction);
-    return instruction;
-  }
-}
-
-/**
- * This class visits the method that is a candidate for inlining and
- * finds whether it is too difficult to inline.
- */
-// TODO(karlklose): refactor to make it possible to distinguish between
-// implementation restrictions (for example, we *can't* inline multiple returns)
-// and heuristics (we *shouldn't* inline large functions).
-class InlineWeeder extends ast.Visitor {
-  // Invariant: *INSIDE_LOOP* > *OUTSIDE_LOOP*
-  static const INLINING_NODES_OUTSIDE_LOOP = 18;
-  static const INLINING_NODES_OUTSIDE_LOOP_ARG_FACTOR = 3;
-  static const INLINING_NODES_INSIDE_LOOP = 42;
-  static const INLINING_NODES_INSIDE_LOOP_ARG_FACTOR = 4;
-
-  bool seenReturn = false;
-  bool tooDifficult = false;
-  int nodeCount = 0;
-  final int maxInliningNodes;
-  final bool useMaxInliningNodes;
-  final bool allowLoops;
-
-  InlineWeeder(this.maxInliningNodes,
-               this.useMaxInliningNodes,
-               this.allowLoops);
-
-  static bool canBeInlined(ast.FunctionExpression functionExpression,
-                           int maxInliningNodes,
-                           bool useMaxInliningNodes,
-                           {bool allowLoops: false}) {
-    InlineWeeder weeder =
-        new InlineWeeder(maxInliningNodes, useMaxInliningNodes, allowLoops);
-    weeder.visit(functionExpression.initializers);
-    weeder.visit(functionExpression.body);
-    return !weeder.tooDifficult;
-  }
-
-  bool registerNode() {
-    if (!useMaxInliningNodes) return true;
-    if (nodeCount++ > maxInliningNodes) {
-      tooDifficult = true;
-      return false;
-    } else {
-      return true;
-    }
-  }
-
-  void visit(ast.Node node) {
-    if (node != null) node.accept(this);
-  }
-
-  void visitNode(ast.Node node) {
-    if (!registerNode()) return;
-    if (seenReturn) {
-      tooDifficult = true;
-    } else {
-      node.visitChildren(this);
-    }
-  }
-
-  void visitFunctionExpression(ast.Node node) {
-    if (!registerNode()) return;
-    tooDifficult = true;
-  }
-
-  void visitFunctionDeclaration(ast.Node node) {
-    if (!registerNode()) return;
-    tooDifficult = true;
-  }
-
-  void visitSend(ast.Send node) {
-    if (!registerNode()) return;
-    node.visitChildren(this);
-  }
-
-  visitLoop(ast.Node node) {
-    // It's actually not difficult to inline a method with a loop, but
-    // our measurements show that it's currently better to not inline a
-    // method that contains a loop.
-    if (!allowLoops) tooDifficult = true;
-  }
-
-  void visitRedirectingFactoryBody(ast.RedirectingFactoryBody node) {
-    if (!registerNode()) return;
-    tooDifficult = true;
-  }
-
-  void visitRethrow(ast.Rethrow node) {
-    if (!registerNode()) return;
-    tooDifficult = true;
-  }
-
-  void visitReturn(ast.Return node) {
-    if (!registerNode()) return;
-    if (seenReturn
-        || identical(node.beginToken.stringValue, 'native')) {
-      tooDifficult = true;
-      return;
-    }
-    node.visitChildren(this);
-    seenReturn = true;
-  }
-
-  void visitTryStatement(ast.Node node) {
-    if (!registerNode()) return;
-    tooDifficult = true;
-  }
-
-  void visitThrow(ast.Throw node) {
-    if (!registerNode()) return;
-    // For now, we don't want to handle throw after a return even if
-    // it is in an "if".
-    if (seenReturn) {
-      tooDifficult = true;
-    } else {
-      node.visitChildren(this);
-    }
-  }
-}
-
-abstract class InliningState {
-  /**
-   * Invariant: [function] must be an implementation element.
-   */
-  final FunctionElement function;
-
-  InliningState(this.function) {
-    assert(function.isImplementation);
-  }
-}
-
-class AstInliningState extends InliningState {
-  final Local oldReturnLocal;
-  final DartType oldReturnType;
-  final TreeElements oldElements;
-  final List<HInstruction> oldStack;
-  final LocalsHandler oldLocalsHandler;
-  final bool inTryStatement;
-  final bool allFunctionsCalledOnce;
-
-  AstInliningState(FunctionElement function,
-                   this.oldReturnLocal,
-                   this.oldReturnType,
-                   this.oldElements,
-                   this.oldStack,
-                   this.oldLocalsHandler,
-                   this.inTryStatement,
-                   this.allFunctionsCalledOnce)
-      : super(function);
-}
-
-class SsaBranch {
-  final SsaBranchBuilder branchBuilder;
-  final HBasicBlock block;
-  LocalsHandler startLocals;
-  LocalsHandler exitLocals;
-  SubGraph graph;
-
-  SsaBranch(this.branchBuilder) : block = new HBasicBlock();
-}
-
-class SsaBranchBuilder {
-  final SsaBuilder builder;
-  final ast.Node diagnosticNode;
-
-  SsaBranchBuilder(this.builder, [this.diagnosticNode]);
-
-  Compiler get compiler => builder.compiler;
-
-  void checkNotAborted() {
-    if (builder.isAborted()) {
-      compiler.unimplemented(diagnosticNode, "aborted control flow");
-    }
-  }
-
-  void buildCondition(void visitCondition(),
-                      SsaBranch conditionBranch,
-                      SsaBranch thenBranch,
-                      SsaBranch elseBranch) {
-    startBranch(conditionBranch);
-    visitCondition();
-    checkNotAborted();
-    assert(identical(builder.current, builder.lastOpenedBlock));
-    HInstruction conditionValue = builder.popBoolified();
-    HIf branch = new HIf(conditionValue);
-    HBasicBlock conditionExitBlock = builder.current;
-    builder.close(branch);
-    conditionBranch.exitLocals = builder.localsHandler;
-    conditionExitBlock.addSuccessor(thenBranch.block);
-    conditionExitBlock.addSuccessor(elseBranch.block);
-    bool conditionBranchLocalsCanBeReused =
-        mergeLocals(conditionBranch, thenBranch, mayReuseFromLocals: true);
-    mergeLocals(conditionBranch, elseBranch,
-                mayReuseFromLocals: conditionBranchLocalsCanBeReused);
-
-    conditionBranch.graph =
-        new SubExpression(conditionBranch.block, conditionExitBlock);
-  }
-
-  /**
-   * Returns true if the locals of the [fromBranch] may be reused. A [:true:]
-   * return value implies that [mayReuseFromLocals] was set to [:true:].
-   */
-  bool mergeLocals(SsaBranch fromBranch, SsaBranch toBranch,
-                   {bool mayReuseFromLocals}) {
-    LocalsHandler fromLocals = fromBranch.exitLocals;
-    if (toBranch.startLocals == null) {
-      if (mayReuseFromLocals) {
-        toBranch.startLocals = fromLocals;
-        return false;
-      } else {
-        toBranch.startLocals = new LocalsHandler.from(fromLocals);
-        return true;
-      }
-    } else {
-      toBranch.startLocals.mergeWith(fromLocals, toBranch.block);
-      return true;
-    }
-  }
-
-  void startBranch(SsaBranch branch) {
-    builder.graph.addBlock(branch.block);
-    builder.localsHandler = branch.startLocals;
-    builder.open(branch.block);
-  }
-
-  HInstruction buildBranch(SsaBranch branch,
-                           void visitBranch(),
-                           SsaBranch joinBranch,
-                           bool isExpression) {
-    startBranch(branch);
-    visitBranch();
-    branch.graph = new SubGraph(branch.block, builder.lastOpenedBlock);
-    branch.exitLocals = builder.localsHandler;
-    if (!builder.isAborted()) {
-      builder.goto(builder.current, joinBranch.block);
-      mergeLocals(branch, joinBranch, mayReuseFromLocals: true);
-    }
-    if (isExpression) {
-      checkNotAborted();
-      return builder.pop();
-    }
-    return null;
-  }
-
-  handleIf(void visitCondition(), void visitThen(), void visitElse()) {
-    if (visitElse == null) {
-      // Make sure to have an else part to avoid a critical edge. A
-      // critical edge is an edge that connects a block with multiple
-      // successors to a block with multiple predecessors. We avoid
-      // such edges because they prevent inserting copies during code
-      // generation of phi instructions.
-      visitElse = () {};
-    }
-
-    _handleDiamondBranch(visitCondition, visitThen, visitElse, false);
-  }
-
-  handleConditional(void visitCondition(), void visitThen(), void visitElse()) {
-    assert(visitElse != null);
-    _handleDiamondBranch(visitCondition, visitThen, visitElse, true);
-  }
-
-  void handleLogicalAndOr(void left(), void right(), {bool isAnd}) {
-    // x && y is transformed into:
-    //   t0 = boolify(x);
-    //   if (t0) {
-    //     t1 = boolify(y);
-    //   }
-    //   result = phi(t1, false);
-    //
-    // x || y is transformed into:
-    //   t0 = boolify(x);
-    //   if (not(t0)) {
-    //     t1 = boolify(y);
-    //   }
-    //   result = phi(t1, true);
-    HInstruction boolifiedLeft;
-    HInstruction boolifiedRight;
-
-    void visitCondition() {
-      left();
-      boolifiedLeft = builder.popBoolified();
-      builder.stack.add(boolifiedLeft);
-      if (!isAnd) {
-        builder.push(new HNot(builder.pop(), builder.backend.boolType));
-      }
-    }
-
-    void visitThen() {
-      right();
-      boolifiedRight = builder.popBoolified();
-    }
-
-    handleIf(visitCondition, visitThen, null);
-    HConstant notIsAnd =
-        builder.graph.addConstantBool(!isAnd, builder.compiler);
-    JavaScriptBackend backend = builder.backend;
-    HPhi result = new HPhi.manyInputs(null,
-                                      <HInstruction>[boolifiedRight, notIsAnd],
-                                      backend.dynamicType);
-    builder.current.addPhi(result);
-    builder.stack.add(result);
-  }
-
-  void handleLogicalAndOrWithLeftNode(ast.Node left,
-                                      void visitRight(),
-                                      {bool isAnd}) {
-    // This method is similar to [handleLogicalAndOr] but optimizes the case
-    // where left is a logical "and" or logical "or".
-    //
-    // For example (x && y) && z is transformed into x && (y && z):
-    //   t0 = boolify(x);
-    //   if (t0) {
-    //     t1 = boolify(y);
-    //     if (t1) {
-    //       t2 = boolify(z);
-    //     }
-    //     t3 = phi(t2, false);
-    //   }
-    //   result = phi(t3, false);
-
-    ast.Send send = left.asSend();
-    if (send != null &&
-        (isAnd ? send.isLogicalAnd : send.isLogicalOr)) {
-      ast.Node newLeft = send.receiver;
-      Link<ast.Node> link = send.argumentsNode.nodes;
-      assert(link.tail.isEmpty);
-      ast.Node middle = link.head;
-      handleLogicalAndOrWithLeftNode(
-          newLeft,
-          () => handleLogicalAndOrWithLeftNode(middle, visitRight,
-                                               isAnd: isAnd),
-          isAnd: isAnd);
-    } else {
-      handleLogicalAndOr(() => builder.visit(left), visitRight, isAnd: isAnd);
-    }
-  }
-
-  void _handleDiamondBranch(void visitCondition(),
-                            void visitThen(),
-                            void visitElse(),
-                            bool isExpression) {
-    SsaBranch conditionBranch = new SsaBranch(this);
-    SsaBranch thenBranch = new SsaBranch(this);
-    SsaBranch elseBranch = new SsaBranch(this);
-    SsaBranch joinBranch = new SsaBranch(this);
-
-    conditionBranch.startLocals = builder.localsHandler;
-    builder.goto(builder.current, conditionBranch.block);
-
-    buildCondition(visitCondition, conditionBranch, thenBranch, elseBranch);
-    HInstruction thenValue =
-        buildBranch(thenBranch, visitThen, joinBranch, isExpression);
-    HInstruction elseValue =
-        buildBranch(elseBranch, visitElse, joinBranch, isExpression);
-
-    if (isExpression) {
-      assert(thenValue != null && elseValue != null);
-      JavaScriptBackend backend = builder.backend;
-      HPhi phi = new HPhi.manyInputs(
-          null, <HInstruction>[thenValue, elseValue], backend.dynamicType);
-      joinBranch.block.addPhi(phi);
-      builder.stack.add(phi);
-    }
-
-    HBasicBlock thenBlock = thenBranch.block;
-    HBasicBlock elseBlock = elseBranch.block;
-    HBasicBlock joinBlock;
-    // If at least one branch did not abort, open the joinBranch.
-    if (!joinBranch.block.predecessors.isEmpty) {
-      startBranch(joinBranch);
-      joinBlock = joinBranch.block;
-    }
-
-    HIfBlockInformation info =
-        new HIfBlockInformation(
-          new HSubExpressionBlockInformation(conditionBranch.graph),
-          new HSubGraphBlockInformation(thenBranch.graph),
-          new HSubGraphBlockInformation(elseBranch.graph));
-
-    HBasicBlock conditionStartBlock = conditionBranch.block;
-    conditionStartBlock.setBlockFlow(info, joinBlock);
-    SubGraph conditionGraph = conditionBranch.graph;
-    HIf branch = conditionGraph.end.last;
-    assert(branch is HIf);
-    branch.blockInformation = conditionStartBlock.blockFlow;
-  }
-}
-
-class TypeBuilder implements DartTypeVisitor<dynamic, SsaBuilder> {
-  final ClassWorld classWorld;
-
-  TypeBuilder(this.classWorld);
-
-  void visitType(DartType type, _) {
-    throw 'Internal error $type';
-  }
-
-  void visitVoidType(VoidType type, SsaBuilder builder) {
-    ClassElement cls = builder.backend.findHelper('VoidRuntimeType');
-    builder.push(new HVoidType(type, new TypeMask.exact(cls, classWorld)));
-  }
-
-  void visitTypeVariableType(TypeVariableType type,
-                             SsaBuilder builder) {
-    ClassElement cls = builder.backend.findHelper('RuntimeType');
-    TypeMask instructionType = new TypeMask.subclass(cls, classWorld);
-    if (!builder.sourceElement.enclosingElement.isClosure &&
-        builder.sourceElement.isInstanceMember) {
-      HInstruction receiver = builder.localsHandler.readThis();
-      builder.push(new HReadTypeVariable(type, receiver, instructionType));
-    } else {
-      builder.push(
-          new HReadTypeVariable.noReceiver(
-              type, builder.addTypeVariableReference(type), instructionType));
-    }
-  }
-
-  void visitFunctionType(FunctionType type, SsaBuilder builder) {
-    type.returnType.accept(this, builder);
-    HInstruction returnType = builder.pop();
-    List<HInstruction> inputs = <HInstruction>[returnType];
-
-    for (DartType parameter in type.parameterTypes) {
-      parameter.accept(this, builder);
-      inputs.add(builder.pop());
-    }
-
-    for (DartType parameter in type.optionalParameterTypes) {
-      parameter.accept(this, builder);
-      inputs.add(builder.pop());
-    }
-
-    List<DartType> namedParameterTypes = type.namedParameterTypes;
-    List<String> names = type.namedParameters;
-    for (int index = 0; index < names.length; index++) {
-      ast.DartString dartString = new ast.DartString.literal(names[index]);
-      inputs.add(
-          builder.graph.addConstantString(dartString, builder.compiler));
-      namedParameterTypes[index].accept(this, builder);
-      inputs.add(builder.pop());
-    }
-
-    ClassElement cls = builder.backend.findHelper('RuntimeFunctionType');
-    builder.push(new HFunctionType(inputs, type,
-        new TypeMask.exact(cls, classWorld)));
-  }
-
-  void visitMalformedType(MalformedType type, SsaBuilder builder) {
-    visitDynamicType(const DynamicType(), builder);
-  }
-
-  void visitStatementType(StatementType type, SsaBuilder builder) {
-    throw 'not implemented visitStatementType($type)';
-  }
-
-  void visitGenericType(GenericType type, SsaBuilder builder) {
-    throw 'not implemented visitGenericType($type)';
-  }
-
-  void visitInterfaceType(InterfaceType type, SsaBuilder builder) {
-    List<HInstruction> inputs = <HInstruction>[];
-    for (DartType typeArgument in type.typeArguments) {
-      typeArgument.accept(this, builder);
-      inputs.add(builder.pop());
-    }
-    ClassElement cls;
-    if (type.typeArguments.isEmpty) {
-      cls = builder.backend.findHelper('RuntimeTypePlain');
-    } else {
-      cls = builder.backend.findHelper('RuntimeTypeGeneric');
-    }
-    builder.push(new HInterfaceType(inputs, type,
-        new TypeMask.exact(cls, classWorld)));
-  }
-
-  void visitTypedefType(TypedefType type, SsaBuilder builder) {
-    DartType unaliased = type.unalias(builder.compiler);
-    if (unaliased is TypedefType) throw 'unable to unalias $type';
-    unaliased.accept(this, builder);
-  }
-
-  void visitDynamicType(DynamicType type, SsaBuilder builder) {
-    JavaScriptBackend backend = builder.compiler.backend;
-    ClassElement cls = backend.findHelper('DynamicRuntimeType');
-    builder.push(new HDynamicType(type, new TypeMask.exact(cls, classWorld)));
-  }
-}