Bug 1896505 - Track Type IV Subclassing in RegExp r=jandem

Differential Revision: https://phabricator.services.mozilla.com/D211458

dom/base/UseCounters.conf

@@ -79,6 +79,7 @@ custom JS_subclassing_typedarray_type_3 TypedArray is Type III subclassed
 custom JS_subclassing_arraybuffer_type_3 ArrayBuffer is Type III subclassed
 custom JS_subclassing_sharedarraybuffer_type_3 SharedArrayBuffer is Type III subclassed
 custom JS_subclassing_regexp_type_3 RegExp is Type III subclassed
+custom JS_subclassing_regexp_type_4 RegExp is Type IV subclassed
 
 // Console API
 method console.assert

dom/base/use_counter_metrics.yaml

@@ -107,8 +107,8 @@ use.counter:
     send_in_pings:
       - use-counters
 
-# Total of 2327 use counter metrics (excludes denominators).
-# Total of 363 'page' use counters.
+# Total of 2329 use counter metrics (excludes denominators).
+# Total of 364 'page' use counters.
 use.counter.page:
   svgsvgelement_getelementbyid:
     type: counter
@@ -688,6 +688,23 @@ use.counter.page:
     send_in_pings:
       - use-counters
 
+  js_subclassing_regexp_type_4:
+    type: counter
+    description: >
+      Whether a page RegExp is Type IV subclassed.
+      Compare against `use.counter.top_level_content_documents_destroyed`
+      to calculate the rate.
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1852098
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1852098
+    notification_emails:
+      - dom-core@mozilla.com
+      - emilio@mozilla.com
+    expires: never
+    send_in_pings:
+      - use-counters
+
   console_assert:
     type: counter
     description: >
@@ -6281,7 +6298,7 @@ use.counter.page:
     send_in_pings:
       - use-counters
 
-# Total of 363 'document' use counters.
+# Total of 364 'document' use counters.
 use.counter.doc:
   svgsvgelement_getelementbyid:
     type: counter
@@ -6861,6 +6878,23 @@ use.counter.doc:
     send_in_pings:
       - use-counters
 
+  js_subclassing_regexp_type_4:
+    type: counter
+    description: >
+      Whether a document RegExp is Type IV subclassed.
+      Compare against `use.counter.content_documents_destroyed`
+      to calculate the rate.
+    bugs:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1852098
+    data_reviews:
+      - https://bugzilla.mozilla.org/show_bug.cgi?id=1852098
+    notification_emails:
+      - dom-core@mozilla.com
+      - emilio@mozilla.com
+    expires: never
+    send_in_pings:
+      - use-counters
+
   console_assert:
     type: counter
     description: >

js/public/friend/UsageStatistics.h

@@ -97,7 +97,8 @@ extern JS_PUBLIC_API void JS_SetAccumulateTelemetryCallback(
   _(SUBCLASSING_ARRAYBUFFER_TYPE_III, SubclassingArrayBufferTypeIII) \
   _(SUBCLASSING_SHAREDARRAYBUFFER_TYPE_III,                          \
     SubclassingSharedArrayBufferTypeIII)                             \
-  _(SUBCLASSING_REGEXP_TYPE_III, SubclassingRegExpTypeIII)
+  _(SUBCLASSING_REGEXP_TYPE_III, SubclassingRegExpTypeIII)           \
+  _(SUBCLASSING_REGEXP_TYPE_IV, SubclassingRegExpTypeIV)
 
 /*
  * Use counter names passed to the accumulate use counter callback.

js/src/builtin/RegExp.cpp

@@ -1907,6 +1907,7 @@ bool js::RegExpExec(JSContext* cx, Handle<JSObject*> regexp,
     return cx->compartment()->wrap(cx, rval);
   }
 
+  ReportUsageCounter(cx, nullptr, SUBCLASSING_REGEXP, SUBCLASSING_TYPE_IV);
   // Step 2.a.
   Rooted<Value> thisv(cx, ObjectValue(*regexp));
   FixedInvokeArgs<1> args(cx);

js/src/builtin/SelfHostingDefines.h

@@ -161,5 +161,7 @@
 
 #define SUBCLASS_REGEXP_TYPE_III \
   ((SUBCLASSING_REGEXP << SUBCLASSING_BUILTIN_SHIFT) | SUBCLASSING_TYPE_III)
+#define SUBCLASS_REGEXP_TYPE_IV \
+  ((SUBCLASSING_REGEXP << SUBCLASSING_BUILTIN_SHIFT) | SUBCLASSING_TYPE_IV)
 
 #endif

js/src/jit-test/tests/use-counters/regexp-counters.js

@@ -67,3 +67,21 @@ function test_regexp_split_type_iii() {
 
 test_function_for_use_counter_integration(test_regexp_split, "SubclassingRegExpTypeIII", false)
 test_function_for_use_counter_integration(test_regexp_split_type_iii, "SubclassingRegExpTypeIII", true)
+
+function test_regexp_exec() {
+    let r = /r/;
+    "s".match(r);
+}
+
+function test_regexp_exec_type_iv() {
+    class R extends RegExp {
+        exec() {
+            return {};
+        }
+    }
+    "s".match(new R("s"));
+}
+
+test_function_for_use_counter_integration(test_regexp_exec, "SubclassingRegExpTypeIV", false)
+test_function_for_use_counter_integration(test_regexp_exec_type_iv, "SubclassingRegExpTypeIV", true)
+

js/src/vm/SelfHosting.cpp

@@ -3111,6 +3111,10 @@ bool js::ReportUsageCounter(JSContext* cx, HandleObject constructorArg,
           cx->runtime()->setUseCounter(
               cx->global(), JSUseCounter::SUBCLASSING_REGEXP_TYPE_III);
           return true;
+        case SUBCLASSING_TYPE_IV:
+          cx->runtime()->setUseCounter(
+              cx->global(), JSUseCounter::SUBCLASSING_REGEXP_TYPE_IV);
+          return true;
         default:
           MOZ_CRASH("Unexpected RegExp Subclassing Type");
       }

js/xpconnect/src/XPCJSRuntime.cpp

@@ -2672,6 +2672,10 @@ static void SetUseCounterCallback(JSObject* obj, JSUseCounter counter) {
       SetUseCounter(obj,
                     mozilla::eUseCounter_custom_JS_subclassing_regexp_type_3);
       return;
+    case JSUseCounter::SUBCLASSING_REGEXP_TYPE_IV:
+      SetUseCounter(obj,
+                    mozilla::eUseCounter_custom_JS_subclassing_regexp_type_4);
+      return;
     case JSUseCounter::COUNT:
       break;
   }