[parsing] Disable scopeinfo sharing for hidden scopes

verwaest · V8 LUCI CQ · commit 3f66bffc0ea9 · 2024-07-12T14:26:10.000Z
They can't be reused anyway. This also dchecks that we won't try to reuse them. Fixed: 352414639 Change-Id: I490500a7616b4dfa6be67798ce9f58a99cb00c17 Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/5701117 Reviewed-by: Leszek Swirski <leszeks@chromium.org> Auto-Submit: Toon Verwaest <verwaest@chromium.org> Commit-Queue: Toon Verwaest <verwaest@chromium.org> Commit-Queue: Leszek Swirski <leszeks@chromium.org> Cr-Commit-Position: refs/heads/main@{#95004}
diff --git a/src/ast/scopes.cc b/src/ast/scopes.cc
@@ -2705,6 +2705,7 @@ void Scope::AllocateScopeInfosRecursively(
     // next outer scope that needs a context.
     next_outer_scope = scope_info_;
     DCHECK(!scope_info_.is_null());
+    DCHECK(!is_hidden());
     CHECK_EQ(scope_info_->scope_type(), scope_type_);
     CHECK_EQ(scope_info_->ContextLength(), num_heap_slots_);
 #ifdef DEBUG
@@ -2713,8 +2714,9 @@ void Scope::AllocateScopeInfosRecursively(
 #endif
   } else if (NeedsScopeInfo()) {
 #ifdef DEBUG
-    // Mark this ID as being used.
-    scope_infos_to_reuse[UniqueIdInScript()] = {};
+    // Mark this ID as being used. Skip hidden scopes because they are
+    // synthetic, unreusable, but hard to make unique.
+    if (!is_hidden()) scope_infos_to_reuse[UniqueIdInScript()] = {};
 #endif
     scope_info_ = ScopeInfo::Create(isolate, zone(), this, outer_scope);
     DCHECK_EQ(UniqueIdInScript(), scope_info_->UniqueIdInScript());
diff --git a/test/mjsunit/regress-4530868594868224.js b/test/mjsunit/regress-4530868594868224.js
@@ -0,0 +1,22 @@
+// Copyright 2024 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.
+
+// Flags: --fuzzing
+
+const __v_2 = [{
+  body: function () {
+  },
+  body: function () {
+  }
+}, {
+  body: function () {
+    const __v_11 = {
+    };
+  }
+}];
+  var __v_30 = [{
+    body: function () {
+        var __v_140 = async () => __v_147 = async () => __v_173 = 'str';
+    }
+  }];
