Add a html-based visualizer for TurboFan graphs

tools/turbolizer/edge.js

+// Copyright 2014 the V8 project authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+var MINIMUM_EDGE_SEPARATION = 20;
+
+function isEdgeInitiallyVisible(target, index, source, type) {
+  return type == "control" && (target.cfg || source.cfg);
+}
+
+var Edge = function(target, index, source, type) {
+  this.target = target;
+  this.source = source;
+  this.index = index;
+  this.type = type;
+  this.backEdgeNumber = 0;
+  this.visible = isEdgeInitiallyVisible(target, index, source, type);
+};
+
+Edge.prototype.stringID = function() {
+  return this.source.id + "," + this.index +  "," + this.target.id;
+};
+
+Edge.prototype.isVisible = function() {
+  return this.visible && this.source.visible && this.target.visible;
+};
+
+Edge.prototype.getInputHorizontalPosition = function(graph) {
+  if (this.backEdgeNumber > 0) {
+    return graph.maxGraphNodeX + this.backEdgeNumber * MINIMUM_EDGE_SEPARATION;
+  }
+  var source = this.source;
+  var target = this.target;
+  var index = this.index;
+  var input_x = target.x + target.getInputX(index);
+  var inputApproach = target.getInputApproach(this.index);
+  var outputApproach = source.getOutputApproach(graph);
+  if (inputApproach > outputApproach) {
+    return input_x;
+  } else {
+    var inputOffset = MINIMUM_EDGE_SEPARATION * (index + 1);
+    return (target.x < source.x)
+      ? (target.x + target.getTotalNodeWidth() + inputOffset)
+      : (target.x - inputOffset)
+  }
+}
+
+Edge.prototype.generatePath = function(graph) {
+  var target = this.target;
+  var source = this.source;
+  var input_x = target.x + target.getInputX(this.index);
+  var output_x = source.x + source.getOutputX();
+  var output_y = source.y + DEFAULT_NODE_HEIGHT + DEFAULT_NODE_BUBBLE_RADIUS;
+  var inputApproach = target.getInputApproach(this.index);
+  var outputApproach = source.getOutputApproach(graph);
+  var horizontalPos = this.getInputHorizontalPosition(graph);
+
+  var result = "M" + output_x + "," + output_y +
+    "L" + output_x + "," + outputApproach +
+    "L" + horizontalPos + "," + outputApproach;
+
+  if (horizontalPos != input_x) {
+    result += "L" + horizontalPos + "," + inputApproach;
+  } else {
+    if (inputApproach < outputApproach) {
+      inputApproach = outputApproach;
+    }
+  }
+
+  result += "L" + input_x + "," + inputApproach +
+    "L" + input_x + "," + (target.y - DEFAULT_NODE_BUBBLE_RADIUS - 12);
+  return result;
+}
+
+Edge.prototype.isBackEdge = function() {
+  return this.target.hasBackEdges() && (this.target.rank < this.source.rank);
+}