[pkg/vm_snapshot_analysis] Use program.stubs as owner for TTS stubs.

Also remove the '<anonymous signature>' check, since we stopped
generating function objects for function types before the current
minimum SDK version for the package.

Change-Id: I47c0522ae4ba778221ee98f93fdae8c22a57d688
Bug: https://github.com/flutter/flutter/issues/128402
Cq-Include-Trybots: luci.dart.try:pkg-linux-debug-try,pkg-linux-release-try,pkg-mac-release-arm64-try,pkg-win-release-try,pkg-mac-release-try
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/307860
Reviewed-by: Slava Egorov <vegorov@google.com>
Commit-Queue: Tess Strickland <sstrickl@google.com>

pkg/vm_snapshot_analysis/CHANGELOG.md

@@ -1,5 +1,10 @@
 # Changelog
 
+## 0.7.4
+
+- Fix for flutter/flutter#128402 where an attempt to lookup the owner info
+node for type testing stubs would cause a null check error.
+
 ## 0.7.3-dev
 
 - Update the readme to document the current way to generate Dart AOT snapshots.

pkg/vm_snapshot_analysis/lib/v8_profile.dart

@@ -414,37 +414,30 @@ class _ProgramInfoBuilder {
     switch (node.type) {
       case 'Code':
         final owner = node['owner_']!;
-        if (owner.type != 'Type') {
-          final ownerNode =
-              owner.type == 'Null' ? program.stubs : getInfoNodeFor(owner)!;
-          if (owner.type == 'Function') {
-            // For normal functions we just attribute Code object and all
-            // objects dominated by it to the function itself.
-            return ownerNode;
-          }
-
-          // For stubs we create a dummy functionNode that is going to own
-          // all objects dominated by it.
-          return makeInfoNode(node.index,
-              name: node.name, parent: ownerNode, type: NodeType.functionNode);
+        if (owner.type == 'Function') {
+          // For normal functions we just attribute Code object and all
+          // objects dominated by it to the function itself.
+          return getInfoNodeFor(owner)!;
         }
-        break;
+        // For all stub types, we create a dummy functionNode that is going to
+        // own all objects dominated by it.
+        final ownerNode =
+            owner.type == 'Class' ? getInfoNodeFor(owner)! : program.stubs;
+        return makeInfoNode(node.index,
+            name: node.name, parent: ownerNode, type: NodeType.functionNode);
 
       case 'Function':
-        if (node.name != '<anonymous signature>') {
-          var owner = node['owner_']!;
+        var owner = node['owner_']!;
 
-          // Artificial nodes may not have a data_ field.
-          var data = node['data_'];
-          if (data != null && data.type == 'ClosureData') {
-            owner = data['parent_function_']!;
-          }
-          return makeInfoNode(node.index,
-              name: node.name,
-              parent: getInfoNodeFor(owner)!,
-              type: NodeType.functionNode);
+        // Artificial nodes may not have a data_ field.
+        var data = node['data_'];
+        if (data != null && data.type == 'ClosureData') {
+          owner = data['parent_function_']!;
         }
-        break;
+        return makeInfoNode(node.index,
+            name: node.name,
+            parent: getInfoNodeFor(owner)!,
+            type: NodeType.functionNode);
 
       case 'PatchClass':
         return getInfoNodeFor(node['patched_class_']!);

pkg/vm_snapshot_analysis/pubspec.yaml

@@ -1,5 +1,5 @@
 name: vm_snapshot_analysis
-version: 0.7.3-dev
+version: 0.7.4
 description: Utilities for analysing AOT snapshot size.
 repository: https://github.com/dart-lang/sdk/tree/main/pkg/vm_snapshot_analysis