Subzero: Generate a web page showing llvm2ice size breakdown.

bloat/webtreemap.js

Index: bloat/webtreemap.js
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+// Copyright 2013 Google Inc. All Rights Reserved.
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+// Size of border around nodes.
+// We could support arbitrary borders using getComputedStyle(), but I am
+// skeptical the extra complexity (and performance hit) is worth it.
+var kBorderWidth = 1;
+
+// Padding around contents.
+// TODO: do this with a nested div to allow it to be CSS-styleable.
+var kPadding = 4;
+
+var focused = null;
+
+function focus(tree) {
+  focused = tree;
+
+  // Hide all visible siblings of all our ancestors by lowering them.
+  var level = 0;
+  var root = tree;
+  while (root.parent) {
+    root = root.parent;
+    level += 1;
+    for (var i = 0, sibling; sibling = root.children[i]; ++i) {
+      if (sibling.dom)
+        sibling.dom.style.zIndex = 0;
+    }
+  }
+  var width = root.dom.offsetWidth;
+  var height = root.dom.offsetHeight;
+  // Unhide (raise) and maximize us and our ancestors.
+  for (var t = tree; t.parent; t = t.parent) {
+    // Shift off by border so we don't get nested borders.
+    // TODO: actually make nested borders work (need to adjust width/height).
+    position(t.dom, -kBorderWidth, -kBorderWidth, width, height);
+    t.dom.style.zIndex = 1;
+  }
+  // And layout into the topmost box.
+  layout(tree, level, width, height);
+}
+
+function makeDom(tree, level) {
+  var dom = document.createElement('div');
+  dom.style.zIndex = 1;
+  dom.className = 'webtreemap-node webtreemap-level' + Math.min(level, 4);
+  if (tree.data['$symbol']) {
+    dom.className += (' webtreemap-symbol-' +
+	tree.data['$symbol'].replace(' ', '_'));
+  }
+  if (tree.data['$dominant_symbol']) {
+    dom.className += (' webtreemap-symbol-' +
+	tree.data['$dominant_symbol'].replace(' ', '_'));
+    dom.className += (' webtreemap-aggregate');
+  }
+
+  dom.onmousedown = function(e) {
+    if (e.button == 0) {
+      if (focused && tree == focused && focused.parent) {
+        focus(focused.parent);
+      } else {
+        focus(tree);
+      }
+    }
+    e.stopPropagation();
+    return true;
+  };
+
+  var caption = document.createElement('div');
+  caption.className = 'webtreemap-caption';
+  caption.innerHTML = tree.name;
+  dom.appendChild(caption);
+
+  tree.dom = dom;
+  return dom;
+}
+
+function position(dom, x, y, width, height) {
+  // CSS width/height does not include border.
+  width -= kBorderWidth*2;
+  height -= kBorderWidth*2;
+
+  dom.style.left   = x + 'px';
+  dom.style.top    = y + 'px';
+  dom.style.width  = Math.max(width, 0) + 'px';
+  dom.style.height = Math.max(height, 0) + 'px';
+}
+
+// Given a list of rectangles |nodes|, the 1-d space available
+// |space|, and a starting rectangle index |start|, compute an span of
+// rectangles that optimizes a pleasant aspect ratio.
+//
+// Returns [end, sum], where end is one past the last rectangle and sum is the
+// 2-d sum of the rectangles' areas.
+function selectSpan(nodes, space, start) {
+  // Add rectangle one by one, stopping when aspect ratios begin to go
+  // bad.  Result is [start,end) covering the best run for this span.
+  // http://scholar.google.com/scholar?cluster=5972512107845615474
+  var node = nodes[start];
+  var rmin = node.data['$area'];  // Smallest seen child so far.
+  var rmax = rmin;                // Largest child.
+  var rsum = 0;                   // Sum of children in this span.
+  var last_score = 0;             // Best score yet found.
+  for (var end = start; node = nodes[end]; ++end) {
+    var size = node.data['$area'];
+    if (size < rmin)
+      rmin = size;
+    if (size > rmax)
+      rmax = size;
+    rsum += size;
+
+    // This formula is from the paper, but you can easily prove to
+    // yourself it's taking the larger of the x/y aspect ratio or the
+    // y/x aspect ratio.  The additional magic fudge constant of 5
+    // makes us prefer wider rectangles to taller ones.
+    var score = Math.max(5*space*space*rmax / (rsum*rsum),
+                         1*rsum*rsum / (space*space*rmin));
+    if (last_score && score > last_score) {
+      rsum -= size;  // Undo size addition from just above.
+      break;
+    }
+    last_score = score;
+  }
+  return [end, rsum];
+}
+
+function layout(tree, level, width, height) {
+  if (!('children' in tree))
+    return;
+
+  var total = tree.data['$area'];
+
+  // XXX why do I need an extra -1/-2 here for width/height to look right?
+  var x1 = 0, y1 = 0, x2 = width - 1, y2 = height - 2;
+  x1 += kPadding; y1 += kPadding;
+  x2 -= kPadding; y2 -= kPadding;
+  y1 += 14;  // XXX get first child height for caption spacing
+
+  var pixels_to_units = Math.sqrt(total / ((x2 - x1) * (y2 - y1)));
+
+  for (var start = 0, child; child = tree.children[start]; ++start) {
+    if (x2 - x1 < 60 || y2 - y1 < 40) {
+      if (child.dom) {
+        child.dom.style.zIndex = 0;
+        position(child.dom, -2, -2, 0, 0);
+      }
+      continue;
+    }
+
+    // In theory we can dynamically decide whether to split in x or y based
+    // on aspect ratio.  In practice, changing split direction with this
+    // layout doesn't look very good.
+    //   var ysplit = (y2 - y1) > (x2 - x1);
+    var ysplit = true;
+
+    var space;  // Space available along layout axis.
+    if (ysplit)
+      space = (y2 - y1) * pixels_to_units;
+    else
+      space = (x2 - x1) * pixels_to_units;
+
+    var span = selectSpan(tree.children, space, start);
+    var end = span[0], rsum = span[1];
+
+    // Now that we've selected a span, lay out rectangles [start,end) in our
+    // available space.
+    var x = x1, y = y1;
+    for (var i = start; i < end; ++i) {
+      child = tree.children[i];
+      if (!child.dom) {
+        child.parent = tree;
+        child.dom = makeDom(child, level + 1);
+        tree.dom.appendChild(child.dom);
+      } else {
+        child.dom.style.zIndex = 1;
+      }
+      var size = child.data['$area'];
+      var frac = size / rsum;
+      if (ysplit) {
+        width = rsum / space;
+        height = size / width;
+      } else {
+        height = rsum / space;
+        width = size / height;
+      }
+      width /= pixels_to_units;
+      height /= pixels_to_units;
+      width = Math.round(width);
+      height = Math.round(height);
+      position(child.dom, x, y, width, height);
+      if ('children' in child) {
+        layout(child, level + 1, width, height);
+      }
+      if (ysplit)
+        y += height;
+      else
+        x += width;
+    }
+
+    // Shrink our available space based on the amount we used.
+    if (ysplit)
+      x1 += Math.round((rsum / space) / pixels_to_units);
+    else
+      y1 += Math.round((rsum / space) / pixels_to_units);
+
+    // end points one past where we ended, which is where we want to
+    // begin the next iteration, but subtract one to balance the ++ in
+    // the loop.
+    start = end - 1;
+  }
+}
+
+function appendTreemap(dom, data) {
+  var style = getComputedStyle(dom, null);
+  var width = parseInt(style.width);
+  var height = parseInt(style.height);
+  if (!data.dom)
+    makeDom(data, 0);
+  dom.appendChild(data.dom);
+  position(data.dom, 0, 0, width, height);
+  layout(data, 0, width, height);
+}