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

pkg/compiler/lib/src/dart_backend/tree_ir_builder.dart

Index: pkg/compiler/lib/src/dart_backend/tree_ir_builder.dart
diff --git a/pkg/compiler/lib/src/dart_backend/tree_ir_builder.dart b/pkg/compiler/lib/src/dart_backend/tree_ir_builder.dart
deleted file mode 100644
index d4ba56ed2a1dd962075aa5193b503d4d0a18cce1..0000000000000000000000000000000000000000
--- a/pkg/compiler/lib/src/dart_backend/tree_ir_builder.dart
+++ /dev/null
@@ -1,477 +0,0 @@
-// Copyright (c) 2014, the Dart project authors.  Please see the AUTHORS file
-// for details. All rights reserved. Use of this source code is governed by a
-// BSD-style license that can be found in the LICENSE file.
-
-library tree_ir_builder;
-
-import '../dart2jslib.dart' as dart2js;
-import '../dart_types.dart';
-import '../elements/elements.dart';
-import '../cps_ir/cps_ir_nodes.dart' as cps_ir;
-import 'tree_ir_nodes.dart';
-
-/**
- * Builder translates from CPS-based IR to direct-style Tree.
- *
- * A call `Invoke(fun, cont, args)`, where cont is a singly-referenced
- * non-exit continuation `Cont(v, body)` is translated into a direct-style call
- * whose value is bound in the continuation body:
- *
- * `LetVal(v, Invoke(fun, args), body)`
- *
- * and the continuation definition is eliminated.  A similar translation is
- * applied to continuation invocations where the continuation is
- * singly-referenced, though such invocations should not appear in optimized
- * IR.
- *
- * A call `Invoke(fun, cont, args)`, where cont is multiply referenced, is
- * translated into a call followed by a jump with an argument:
- *
- * `Jump L(Invoke(fun, args))`
- *
- * and the continuation is translated into a named block that takes an
- * argument:
- *
- * `LetLabel(L, v, body)`
- *
- * Block arguments are later replaced with data flow during the Tree-to-Tree
- * translation out of SSA.  Jumps are eliminated during the Tree-to-Tree
- * control-flow recognition.
- *
- * Otherwise, the output of Builder looks very much like the input.  In
- * particular, intermediate values and blocks used for local control flow are
- * still all named.
- */
-class Builder extends cps_ir.Visitor<Node> {
-  final dart2js.Compiler compiler;
-
-  /// Maps variable/parameter elements to the Tree variables that represent it.
-  final Map<Element, List<Variable>> element2variables =
-      <Element,List<Variable>>{};
-
-  /// Like [element2variables], except for closure variables. Closure variables
-  /// are not subject to SSA, so at most one variable is used per local.
-  final Map<Local, Variable> local2closure = <Local, Variable>{};
-
-  // Continuations with more than one use are replaced with Tree labels.  This
-  // is the mapping from continuations to labels.
-  final Map<cps_ir.Continuation, Label> labels = <cps_ir.Continuation, Label>{};
-
-  FunctionDefinition function;
-  cps_ir.Continuation returnContinuation;
-
-  Builder parent;
-
-  Builder(this.compiler);
-
-  Builder.inner(Builder parent)
-      : this.parent = parent,
-        compiler = parent.compiler;
-
-  /// Variable used in [buildPhiAssignments] as a temporary when swapping
-  /// variables.
-  Variable phiTempVar;
-
-  Variable getClosureVariable(Local local) {
-    if (local.executableContext != function.element) {
-      return parent.getClosureVariable(local);
-    }
-    Variable variable = local2closure[local];
-    if (variable == null) {
-      variable = new Variable(function, local);
-      local2closure[local] = variable;
-    }
-    return variable;
-  }
-
-  /// Obtains the variable representing the given primitive. Returns null for
-  /// primitives that have no reference and do not need a variable.
-  Variable getVariable(cps_ir.Primitive primitive) {
-    if (primitive.registerIndex == null) {
-      return null; // variable is unused
-    }
-    List<Variable> variables = element2variables[primitive.hint];
-    if (variables == null) {
-      variables = <Variable>[];
-      element2variables[primitive.hint] = variables;
-    }
-    while (variables.length <= primitive.registerIndex) {
-      variables.add(new Variable(function, primitive.hint));
-    }
-    return variables[primitive.registerIndex];
-  }
-
-  /// Obtains a reference to the tree Variable corresponding to the IR primitive
-  /// referred to by [reference].
-  /// This increments the reference count for the given variable, so the
-  /// returned expression must be used in the tree.
-  Expression getVariableReference(cps_ir.Reference reference) {
-    Variable variable = getVariable(reference.definition);
-    if (variable == null) {
-      compiler.internalError(
-          compiler.currentElement,
-          "Reference to ${reference.definition} has no register");
-    }
-    ++variable.readCount;
-    return variable;
-  }
-
-  FunctionDefinition build(cps_ir.FunctionDefinition node) {
-    visit(node);
-    return function;
-  }
-
-  List<Expression> translateArguments(List<cps_ir.Reference> args) {
-    return new List<Expression>.generate(args.length,
-         (int index) => getVariableReference(args[index]));
-  }
-
-  List<Variable> translatePhiArguments(List<cps_ir.Reference> args) {
-    return new List<Variable>.generate(args.length,
-         (int index) => getVariableReference(args[index]));
-  }
-
-  Statement buildContinuationAssignment(
-      cps_ir.Parameter parameter,
-      Expression argument,
-      Statement buildRest()) {
-    Variable variable = getVariable(parameter);
-    Statement assignment;
-    if (variable == null) {
-      assignment = new ExpressionStatement(argument, null);
-    } else {
-      assignment = new Assign(variable, argument, null);
-    }
-    assignment.next = buildRest();
-    return assignment;
-  }
-
-  /// Simultaneously assigns each argument to the corresponding parameter,
-  /// then continues at the statement created by [buildRest].
-  Statement buildPhiAssignments(
-      List<cps_ir.Parameter> parameters,
-      List<Variable> arguments,
-      Statement buildRest()) {
-    assert(parameters.length == arguments.length);
-    // We want a parallel assignment to all parameters simultaneously.
-    // Since we do not have parallel assignments in dart_tree, we must linearize
-    // the assignments without attempting to read a previously-overwritten
-    // value. For example {x,y = y,x} cannot be linearized to {x = y; y = x},
-    // for this we must introduce a temporary variable: {t = x; x = y; y = t}.
-
-    // [rightHand] is the inverse of [arguments], that is, it maps variables
-    // to the assignments on which is occurs as the right-hand side.
-    Map<Variable, List<int>> rightHand = <Variable, List<int>>{};
-    for (int i = 0; i < parameters.length; i++) {
-      Variable param = getVariable(parameters[i]);
-      Variable arg = arguments[i];
-      if (param == null || param == arg) {
-        continue; // No assignment necessary.
-      }
-      List<int> list = rightHand[arg];
-      if (list == null) {
-        rightHand[arg] = list = <int>[];
-      }
-      list.add(i);
-    }
-
-    Statement first, current;
-    void addAssignment(Variable dst, Variable src) {
-      if (first == null) {
-        first = current = new Assign(dst, src, null);
-      } else {
-        current = current.next = new Assign(dst, src, null);
-      }
-    }
-
-    List<Variable> assignmentSrc = new List<Variable>(parameters.length);
-    List<bool> done = new List<bool>(parameters.length);
-    void visitAssignment(int i) {
-      if (done[i] == true) {
-        return;
-      }
-      Variable param = getVariable(parameters[i]);
-      Variable arg = arguments[i];
-      if (param == null || param == arg) {
-        return; // No assignment necessary.
-      }
-      if (assignmentSrc[i] != null) {
-        // Cycle found; store argument in a temporary variable.
-        // The temporary will then be used as right-hand side when the
-        // assignment gets added.
-        if (assignmentSrc[i] != phiTempVar) { // Only move to temporary once.
-          assignmentSrc[i] = phiTempVar;
-          addAssignment(phiTempVar, arg);
-        }
-        return;
-      }
-      assignmentSrc[i] = arg;
-      List<int> paramUses = rightHand[param];
-      if (paramUses != null) {
-        for (int useIndex in paramUses) {
-          visitAssignment(useIndex);
-        }
-      }
-      addAssignment(param, assignmentSrc[i]);
-      done[i] = true;
-    }
-
-    for (int i = 0; i < parameters.length; i++) {
-      if (done[i] == null) {
-        visitAssignment(i);
-      }
-    }
-
-    if (first == null) {
-      first = buildRest();
-    } else {
-      current.next = buildRest();
-    }
-    return first;
-  }
-
-  visitNode(cps_ir.Node node) => throw "Unhandled node: $node";
-
-  Expression visitFunctionDefinition(cps_ir.FunctionDefinition node) {
-    List<Variable> parameters = <Variable>[];
-    function = new FunctionDefinition(node.element, parameters,
-        null, node.localConstants, node.defaultParameterValues);
-    returnContinuation = node.returnContinuation;
-    for (cps_ir.Parameter p in node.parameters) {
-      Variable parameter = getVariable(p);
-      assert(parameter != null);
-      ++parameter.writeCount; // Being a parameter counts as a write.
-      parameters.add(parameter);
-    }
-    if (!node.isAbstract) {
-      phiTempVar = new Variable(function, null);
-      function.body = visit(node.body);
-    }
-    return null;
-  }
-
-  Statement visitLetPrim(cps_ir.LetPrim node) {
-    Variable variable = getVariable(node.primitive);
-
-    // Don't translate unused primitives.
-    if (variable == null) return visit(node.body);
-
-    Node definition = visit(node.primitive);
-
-    // visitPrimitive returns a Statement without successor if it cannot occur
-    // in expression context (currently only the case for FunctionDeclarations).
-    if (definition is Statement) {
-      definition.next = visit(node.body);
-      return definition;
-    } else {
-      return new Assign(variable, definition, visit(node.body));
-    }
-  }
-
-  Statement visitLetCont(cps_ir.LetCont node) {
-    Label label;
-    if (node.continuation.hasMultipleUses) {
-      label = new Label();
-      labels[node.continuation] = label;
-    }
-    Statement body = visit(node.body);
-    // The continuation's body is not always translated directly here because
-    // it may have been already translated:
-    //   * For singly-used continuations, the continuation's body is
-    //     translated at the site of the continuation invocation.
-    //   * For recursive continuations, there is a single non-recursive
-    //     invocation.  The continuation's body is translated at the site
-    //     of the non-recursive continuation invocation.
-    // See visitInvokeContinuation for the implementation.
-    if (label == null || node.continuation.isRecursive) return body;
-    return new LabeledStatement(label, body, visit(node.continuation.body));
-  }
-
-  Statement visitInvokeStatic(cps_ir.InvokeStatic node) {
-    // Calls are translated to direct style.
-    List<Expression> arguments = translateArguments(node.arguments);
-    Expression invoke = new InvokeStatic(node.target, node.selector, arguments);
-    return continueWithExpression(node.continuation, invoke);
-  }
-
-  Statement visitInvokeMethod(cps_ir.InvokeMethod node) {
-    Expression receiver = getVariableReference(node.receiver);
-    List<Expression> arguments = translateArguments(node.arguments);
-    Expression invoke = new InvokeMethod(receiver, node.selector, arguments);
-    return continueWithExpression(node.continuation, invoke);
-  }
-
-  Statement visitInvokeSuperMethod(cps_ir.InvokeSuperMethod node) {
-    List<Expression> arguments = translateArguments(node.arguments);
-    Expression invoke = new InvokeSuperMethod(node.selector, arguments);
-    return continueWithExpression(node.continuation, invoke);
-  }
-
-  Statement visitConcatenateStrings(cps_ir.ConcatenateStrings node) {
-    List<Expression> arguments = translateArguments(node.arguments);
-    Expression concat = new ConcatenateStrings(arguments);
-    return continueWithExpression(node.continuation, concat);
-  }
-
-  Statement continueWithExpression(cps_ir.Reference continuation,
-                                   Expression expression) {
-    cps_ir.Continuation cont = continuation.definition;
-    if (cont == returnContinuation) {
-      return new Return(expression);
-    } else {
-      assert(cont.parameters.length == 1);
-      Function nextBuilder = cont.hasExactlyOneUse ?
-          () => visit(cont.body) : () => new Break(labels[cont]);
-      return buildContinuationAssignment(cont.parameters.single, expression,
-          nextBuilder);
-    }
-  }
-
-  Expression visitGetClosureVariable(cps_ir.GetClosureVariable node) {
-    return getClosureVariable(node.variable);
-  }
-
-  Statement visitSetClosureVariable(cps_ir.SetClosureVariable node) {
-    Variable variable = getClosureVariable(node.variable);
-    Expression value = getVariableReference(node.value);
-    return new Assign(variable, value, visit(node.body),
-                      isDeclaration: node.isDeclaration);
-  }
-
-  Statement visitDeclareFunction(cps_ir.DeclareFunction node) {
-    Variable variable = getClosureVariable(node.variable);
-    FunctionDefinition function = makeSubFunction(node.definition);
-    return new FunctionDeclaration(variable, function, visit(node.body));
-  }
-
-  Statement visitTypeOperator(cps_ir.TypeOperator node) {
-    Expression receiver = getVariableReference(node.receiver);
-    Expression concat =
-        new TypeOperator(receiver, node.type, isTypeTest: node.isTypeTest);
-    return continueWithExpression(node.continuation, concat);
-  }
-
-  Statement visitInvokeConstructor(cps_ir.InvokeConstructor node) {
-    List<Expression> arguments = translateArguments(node.arguments);
-    Expression invoke =
-        new InvokeConstructor(node.type, node.target, node.selector, arguments);
-    return continueWithExpression(node.continuation, invoke);
-  }
-
-  Statement visitInvokeContinuation(cps_ir.InvokeContinuation node) {
-    // Invocations of the return continuation are translated to returns.
-    // Other continuation invocations are replaced with assignments of the
-    // arguments to formal parameter variables, followed by the body if
-    // the continuation is singly reference or a break if it is multiply
-    // referenced.
-    cps_ir.Continuation cont = node.continuation.definition;
-    if (cont == returnContinuation) {
-      assert(node.arguments.length == 1);
-      return new Return(getVariableReference(node.arguments.single));
-    } else {
-      List<Expression> arguments = translatePhiArguments(node.arguments);
-      return buildPhiAssignments(cont.parameters, arguments,
-          () {
-            // Translate invocations of recursive and non-recursive
-            // continuations differently.
-            //   * Non-recursive continuations
-            //     - If there is one use, translate the continuation body
-            //       inline at the invocation site.
-            //     - If there are multiple uses, translate to Break.
-            //   * Recursive continuations
-            //     - There is a single non-recursive invocation.  Translate
-            //       the continuation body inline as a labeled loop at the
-            //       invocation site.
-            //     - Translate the recursive invocations to Continue.
-            if (cont.isRecursive) {
-              return node.isRecursive
-                  ? new Continue(labels[cont])
-                  : new WhileTrue(labels[cont], visit(cont.body));
-            } else {
-              return cont.hasExactlyOneUse
-                  ? visit(cont.body)
-                  : new Break(labels[cont]);
-            }
-          });
-    }
-  }
-
-  Statement visitBranch(cps_ir.Branch node) {
-    Expression condition = visit(node.condition);
-    Statement thenStatement, elseStatement;
-    cps_ir.Continuation cont = node.trueContinuation.definition;
-    assert(cont.parameters.isEmpty);
-    thenStatement =
-        cont.hasExactlyOneUse ? visit(cont.body) : new Break(labels[cont]);
-    cont = node.falseContinuation.definition;
-    assert(cont.parameters.isEmpty);
-    elseStatement =
-        cont.hasExactlyOneUse ? visit(cont.body) : new Break(labels[cont]);
-    return new If(condition, thenStatement, elseStatement);
-  }
-
-  Expression visitConstant(cps_ir.Constant node) {
-    return new Constant(node.expression);
-  }
-
-  Expression visitThis(cps_ir.This node) {
-    return new This();
-  }
-
-  Expression visitReifyTypeVar(cps_ir.ReifyTypeVar node) {
-    return new ReifyTypeVar(node.typeVariable);
-  }
-
-  Expression visitLiteralList(cps_ir.LiteralList node) {
-    return new LiteralList(
-            node.type,
-            translateArguments(node.values));
-  }
-
-  Expression visitLiteralMap(cps_ir.LiteralMap node) {
-    return new LiteralMap(
-        node.type,
-        new List<LiteralMapEntry>.generate(node.entries.length, (int index) {
-          return new LiteralMapEntry(
-              getVariableReference(node.entries[index].key),
-              getVariableReference(node.entries[index].value));
-        })
-    );
-  }
-
-  FunctionDefinition makeSubFunction(cps_ir.FunctionDefinition function) {
-    return new Builder.inner(this).build(function);
-  }
-
-  Node visitCreateFunction(cps_ir.CreateFunction node) {
-    FunctionDefinition def = makeSubFunction(node.definition);
-    FunctionType type = node.definition.element.type;
-    bool hasReturnType = !type.returnType.treatAsDynamic;
-    if (hasReturnType) {
-      // This function cannot occur in expression context.
-      // The successor will be filled in by visitLetPrim.
-      return new FunctionDeclaration(getVariable(node), def, null);
-    } else {
-      return new FunctionExpression(def);
-    }
-  }
-
-  Expression visitParameter(cps_ir.Parameter node) {
-    // Continuation parameters are not visited (continuations themselves are
-    // not visited yet).
-    compiler.internalError(compiler.currentElement, 'Unexpected IR node.');
-    return null;
-  }
-
-  Expression visitContinuation(cps_ir.Continuation node) {
-    // Until continuations with multiple uses are supported, they are not
-    // visited.
-    compiler.internalError(compiler.currentElement, 'Unexpected IR node.');
-    return null;
-  }
-
-  Expression visitIsTrue(cps_ir.IsTrue node) {
-    return getVariableReference(node.value);
-  }
-}
-