When inlining, create a new local handler, to avoid polluting the local handler of the caller.

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

 // 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 special element for the extra parameter taken by intercepted
  * methods. We need to override [Element.computeType] because our
  * optimizers may look at its declared type.
@@ skipping 991 matching lines @@
 
     // Once we start to compile the arguments we must be sure that we don't
     // abort.
     List<HInstruction> compiledArguments = new List<HInstruction>();
     bool succeeded = addStaticSendArgumentsToList(selector,
                                                   arguments,
                                                   function,
                                                   compiledArguments);
     assert(succeeded);
 
+    // Create the inlining state after evaluating the arguments, that
+    // may have an impact on the state of the current method.
+    InliningState state = new InliningState(
+        function, returnElement, returnType, elements, stack, localsHandler);
+    localsHandler = new LocalsHandler.from(localsHandler);
+
     FunctionSignature signature = function.computeSignature(compiler);
     int index = 0;
     signature.orderedForEachParameter((Element parameter) {
       HInstruction argument = compiledArguments[index++];
       localsHandler.updateLocal(parameter, argument);
       potentiallyCheckType(argument, parameter.computeType(compiler));
     });
 
     if (function.isConstructor()) {
       ClassElement enclosing = function.getEnclosingClass();
       if (compiler.world.needsRti(enclosing)) {
         assert(currentNode is NewExpression);
         InterfaceType type = elements.getType(currentNode);
         Link<DartType> typeVariable = enclosing.typeVariables;
         type.typeArguments.forEach((DartType argument) {
           HInstruction instruction =
               analyzeTypeArgument(argument, currentNode);
           localsHandler.updateLocal(typeVariable.head.element, instruction);
           typeVariable = typeVariable.tail;
         });
         while (!typeVariable.isEmpty) {
           localsHandler.updateLocal(typeVariable.head.element,
                                     graph.addConstantNull(constantSystem));
           typeVariable = typeVariable.tail;
         }
       }
     }
-    InliningState state =
-        new InliningState(function, returnElement, returnType, elements, stack);
 
     // TODO(kasperl): Bad smell. We shouldn't be constructing elements here.
     returnElement = new ElementX(const SourceString("result"),
                                  ElementKind.VARIABLE,
                                  function);
     localsHandler.updateLocal(returnElement,
                               graph.addConstantNull(constantSystem));
     elements = compiler.enqueuer.resolution.getCachedElements(function);
     assert(elements != null);
     returnType = signature.returnType;
     stack = <HInstruction>[];
     inliningStack.add(state);
     return state;
   }
 
   void leaveInlinedMethod(InliningState state) {
     InliningState poppedState = inliningStack.removeLast();
     assert(state == poppedState);
     elements = state.oldElements;
     stack.add(localsHandler.readLocal(returnElement));
     returnElement = state.oldReturnElement;
     returnType = state.oldReturnType;
     assert(stack.length == 1);
     state.oldStack.add(stack[0]);
     stack = state.oldStack;
+    localsHandler = state.oldLocalsHandler;
   }
 
   /**
    * 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,
                        Link<Node> arguments,
                        Node currentNode) {
@@ skipping 3751 matching lines @@
   /**
    * Documentation wanted -- johnniwinther
    *
    * Invariant: [function] must be an implementation element.
    */
   final PartialFunctionElement function;
   final Element oldReturnElement;
   final DartType oldReturnType;
   final TreeElements oldElements;
   final List<HInstruction> oldStack;
+  final LocalsHandler oldLocalsHandler;
 
   InliningState(this.function,
                 this.oldReturnElement,
                 this.oldReturnType,
                 this.oldElements,
-                this.oldStack) {
+                this.oldStack,
+                this.oldLocalsHandler) {
     assert(function.isImplementation);
   }
 }
 
 class SsaBranch {
   final SsaBranchBuilder branchBuilder;
   final HBasicBlock block;
   LocalsHandler startLocals;
   LocalsHandler exitLocals;
   SubGraph graph;
@@ skipping 219 matching lines @@
           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;
   }
 }