Move frog/leg to lib/compiler/implementation.

frog/leg/ssa/types.dart

-// Copyright (c) 2011, 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.
-
-class SsaTypePropagator extends HGraphVisitor implements OptimizationPhase {
-
-  final Map<int, HInstruction> workmap;
-  final List<int> worklist;
-  final Compiler compiler;
-  final String name = 'type propagator';
-
-  SsaTypePropagator(Compiler this.compiler)
-      : workmap = new Map<int, HInstruction>(),
-        worklist = new List<int>();
-
-  void visitGraph(HGraph graph) {
-    visitDominatorTree(graph);
-    processWorklist();
-  }
-
-  visitBasicBlock(HBasicBlock block) {
-    if (block.isLoopHeader()) {
-      block.forEachPhi((HPhi phi) {
-        phi.setInitialTypeForLoopPhi();
-        addToWorkList(phi);
-      });
-    } else {
-      block.forEachPhi((HPhi phi) {
-        if (phi.updateType()) addUsersAndInputsToWorklist(phi);
-      });
-    }
-
-    HInstruction instruction = block.first;
-    while (instruction !== null) {
-      if (instruction.updateType()) addUsersAndInputsToWorklist(instruction);
-      instruction = instruction.next;
-    }
-  }
-
-  void processWorklist() {
-    while (!worklist.isEmpty()) {
-      int id = worklist.removeLast();
-      HInstruction instruction = workmap[id];
-      assert(instruction !== null);
-      workmap.remove(id);
-      if (instruction.updateType()) addUsersAndInputsToWorklist(instruction);
-    }
-  }
-
-  void addUsersAndInputsToWorklist(HInstruction instruction) {
-    for (int i = 0, length = instruction.usedBy.length; i < length; i++) {
-      addToWorkList(instruction.usedBy[i]);
-    }
-    for (int i = 0, length = instruction.inputs.length; i < length; i++) {
-      addToWorkList(instruction.inputs[i]);
-    }
-  }
-
-  void addToWorkList(HInstruction instruction) {
-    final int id = instruction.id;
-    if (!workmap.containsKey(id)) {
-      worklist.add(id);
-      workmap[id] = instruction;
-    }
-  }
-}