Add generateCallGraphWithDominators method to generate a CallGraph from a precompiler trace.

kenzieschmoll · commit-bot@chromium.org · commit 42dfb9d3046f · 2020-09-02T16:24:42.000Z
Exposing this functionality makes it possible to use this logic in Dart DevTools. This CL also includes some renames that make the code more readable. When there are both `ProgramInfoNode`s and `CallGraphNode`s in scope, the name "node" is ambiguous. Bug: #43169 Change-Id: Ic8ef04e10c48db011cd28e1786bee34223766e47 Cq-Include-Trybots: luci.dart.try:pkg-linux-release-try,pkg-win-release-try,pkg-mac-release-try Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/160342 Commit-Queue: Kenzie Schmoll <kenzieschmoll@google.com> Reviewed-by: Vyacheslav Egorov <vegorov@google.com>
diff --git a/pkg/vm_snapshot_analysis/CHANGELOG.md b/pkg/vm_snapshot_analysis/CHANGELOG.md
@@ -5,6 +5,8 @@
 depth of outputted dependency trees configurable.
 - Rename `deps-collapse-depth` (formerly `-d`) flag for `summary` command to
 `deps-start-depth` (now `-s`).
+- Add `generateCallGraphWithDominators` method that generates a `CallGraph`
+object from precompiler trace.
 
 ## 0.5.4
 - Fix bug causing name clash for Type class.
diff --git a/pkg/vm_snapshot_analysis/lib/precompiler_trace.dart b/pkg/vm_snapshot_analysis/lib/precompiler_trace.dart
@@ -105,21 +105,21 @@ class CallGraph {
 
   // Mapping from [ProgramInfoNode] to a corresponding [CallGraphNode] (if any)
   // via [ProgramInfoNode.id].
-  final List<CallGraphNode> _nodeByEntityId;
+  final List<CallGraphNode> _graphNodeByEntityId;
 
-  CallGraph._(this.program, this.nodes, this._nodeByEntityId);
+  CallGraph._(this.program, this.nodes, this._graphNodeByEntityId);
 
   CallGraphNode get root => nodes.first;
 
-  CallGraphNode lookup(ProgramInfoNode node) => _nodeByEntityId[node.id];
+  CallGraphNode lookup(ProgramInfoNode node) => _graphNodeByEntityId[node.id];
 
   Iterable<CallGraphNode> get dynamicCalls =>
       nodes.where((n) => n.isDynamicCallNode);
 
   /// Compute a collapsed version of the call-graph, where
   CallGraph collapse(NodeType type, {bool dropCallNodes = false}) {
-    final nodesByData = <Object, CallGraphNode>{};
-    final nodeByEntityId = <CallGraphNode>[];
+    final graphNodesByData = <Object, CallGraphNode>{};
+    final graphNodeByEntityId = <CallGraphNode>[];
 
     ProgramInfoNode collapsed(ProgramInfoNode nn) {
       // Root always collapses onto itself.
@@ -138,24 +138,24 @@ class CallGraph {
       return n;
     }
 
-    CallGraphNode nodeFor(Object data) {
-      return nodesByData.putIfAbsent(data, () {
-        final n = CallGraphNode(nodesByData.length, data: data);
+    CallGraphNode callGraphNodeFor(Object data) {
+      return graphNodesByData.putIfAbsent(data, () {
+        final n = CallGraphNode(graphNodesByData.length, data: data);
         if (data is ProgramInfoNode) {
-          if (nodeByEntityId.length <= data.id) {
-            nodeByEntityId.length = data.id * 2 + 1;
+          if (graphNodeByEntityId.length <= data.id) {
+            graphNodeByEntityId.length = data.id * 2 + 1;
           }
-          nodeByEntityId[data.id] = n;
+          graphNodeByEntityId[data.id] = n;
         }
         return n;
       });
     }
 
     final newNodes = nodes.map((n) {
       if (n.data is ProgramInfoNode) {
-        return nodeFor(collapsed(n.data));
+        return callGraphNodeFor(collapsed(n.data));
       } else if (!dropCallNodes) {
-        return nodeFor(n.data);
+        return callGraphNodeFor(n.data);
       }
     }).toList(growable: false);
 
@@ -170,8 +170,8 @@ class CallGraph {
       }
     }
 
-    return CallGraph._(
-        program, nodesByData.values.toList(growable: false), nodeByEntityId);
+    return CallGraph._(program, graphNodesByData.values.toList(growable: false),
+        graphNodeByEntityId);
   }
 
   /// Compute dominator tree of the call-graph.
@@ -529,3 +529,21 @@ class _TraceReader {
         name: libraryUri, parent: node, type: NodeType.libraryNode);
   }
 }
+
+/// Generates a [CallGraph] from the given [precompilerTrace], which is produced
+/// by `--trace-precompiler-to`, then collapses it down to the granularity
+/// specified by [nodeType], and computes dominators of the resulting graph.
+CallGraph generateCallGraphWithDominators(
+  Object precompilerTrace,
+  NodeType nodeType,
+) {
+  var callGraph = loadTrace(precompilerTrace);
+
+  // Convert call graph into the approximate dependency graph, dropping any
+  // dynamic and dispatch table based dependencies from the graph and only
+  // following the static call, field access and allocation edges.
+  callGraph = callGraph.collapse(nodeType, dropCallNodes: true)
+    ..computeDominators();
+
+  return callGraph;
+}
diff --git a/pkg/vm_snapshot_analysis/lib/src/commands/summary.dart b/pkg/vm_snapshot_analysis/lib/src/commands/summary.dart
@@ -187,17 +187,13 @@ void outputSummary(File input,
       (granularity == HistogramType.byLibrary ||
           granularity == HistogramType.byPackage)) {
     final traceJsonRaw = await loadJsonFromFile(traceJson);
-    var callGraph = loadTrace(traceJsonRaw);
-
-    // Convert call graph into the approximate dependency graph, dropping any
-    // dynamic and dispatch table based dependencies from the graph and only
-    // following the static call, field access and allocation edges.
-    callGraph = callGraph.collapse(
-        granularity == HistogramType.byLibrary
-            ? NodeType.libraryNode
-            : NodeType.packageNode,
-        dropCallNodes: true);
-    callGraph.computeDominators();
+
+    final callGraph = generateCallGraphWithDominators(
+      traceJsonRaw,
+      granularity == HistogramType.byLibrary
+          ? NodeType.libraryNode
+          : NodeType.packageNode,
+    );
 
     // Compute name mapping from histogram buckets to new coarser buckets, by
     // collapsing dependency tree at [depsStartDepth] level: node 'Foo' with
diff --git a/pkg/vm_snapshot_analysis/pubspec.yaml b/pkg/vm_snapshot_analysis/pubspec.yaml
@@ -1,6 +1,6 @@
 name: vm_snapshot_analysis
 description: Utilities for analysing AOT snapshot size.
-version: 0.5.5-dev.1
+version: 0.5.5
 
 homepage: https://github.com/dart-lang/sdk/tree/master/pkg/vm_snapshot_analysis
 
