deps: V8: revert CL 5331688

On Windows debug builds, it is not allowed to dereference empty
iterators.

Refs: https://chromium-review.googlesource.com/c/v8/v8/+/5331688
PR-URL: #52465
Reviewed-By: Matteo Collina <[email protected]>
Reviewed-By: Rafael Gonzaga <[email protected]>
Reviewed-By: Michael Dawson <[email protected]>

Author: targos

common.gypi

@@ -36,7 +36,7 @@
 
     # Reset this number to 0 on major V8 upgrades.
     # Increment by one for each non-official patch applied to deps/v8.
-    'v8_embedder_string': '-node.7',
+    'v8_embedder_string': '-node.8',
 
     ##### V8 defaults for Node.js #####
 

deps/v8/src/compiler/js-heap-broker.cc

@@ -855,10 +855,7 @@ ElementAccessFeedback const& JSHeapBroker::ProcessFeedbackMapsForElementAccess(
       MapUpdaterGuardIfNeeded mumd_scope(this);
 
       transition_target = map.object()->FindElementsKindTransitionedMap(
-          isolate(),
-          MapHandlesSpan(possible_transition_targets.begin(),
-                         possible_transition_targets.end()),
-          ConcurrencyMode::kConcurrent);
+          isolate(), possible_transition_targets, ConcurrencyMode::kConcurrent);
     }
 
     if (transition_target.is_null()) {

deps/v8/src/ic/ic.cc

@@ -374,7 +374,7 @@ void IC::ConfigureVectorState(Handle<Name> name, Handle<Map> map,
   OnFeedbackChanged(IsLoadGlobalIC() ? "LoadGlobal" : "Monomorphic");
 }
 
-void IC::ConfigureVectorState(Handle<Name> name, MapHandlesSpan maps,
+void IC::ConfigureVectorState(Handle<Name> name, MapHandles const& maps,
                               MaybeObjectHandles* handlers) {
   DCHECK(!IsGlobalIC());
   std::vector<MapAndHandler> maps_and_handlers;
@@ -740,9 +740,10 @@ bool IC::IsTransitionOfMonomorphicTarget(Tagged<Map> source_map,
       source_map->elements_kind(), target_elements_kind);
   Tagged<Map> transitioned_map;
   if (more_general_transition) {
-    Handle<Map> single_map[1] = {handle(target_map, isolate_)};
+    MapHandles map_list;
+    map_list.push_back(handle(target_map, isolate_));
     transitioned_map = source_map->FindElementsKindTransitionedMap(
-        isolate(), single_map, ConcurrencyMode::kSynchronous);
+        isolate(), map_list, ConcurrencyMode::kSynchronous);
   }
   return transitioned_map == target_map;
 }
@@ -1244,10 +1245,7 @@ void KeyedLoadIC::UpdateLoadElement(Handle<HeapObject> receiver,
   if (target_receiver_maps.size() == 1) {
     ConfigureVectorState(Handle<Name>(), target_receiver_maps[0], handlers[0]);
   } else {
-    ConfigureVectorState(Handle<Name>(),
-                         MapHandlesSpan(target_receiver_maps.begin(),
-                                        target_receiver_maps.end()),
-                         &handlers);
+    ConfigureVectorState(Handle<Name>(), target_receiver_maps, &handlers);
   }
 }
 
@@ -1444,9 +1442,7 @@ void KeyedLoadIC::LoadElementPolymorphicHandlers(
     // generate an elements kind transition for this kind of receivers.
     if (receiver_map->is_stable()) {
       Tagged<Map> tmap = receiver_map->FindElementsKindTransitionedMap(
-          isolate(),
-          MapHandlesSpan(receiver_maps->begin(), receiver_maps->end()),
-          ConcurrencyMode::kSynchronous);
+          isolate(), *receiver_maps, ConcurrencyMode::kSynchronous);
       if (!tmap.is_null()) {
         receiver_map->NotifyLeafMapLayoutChange(isolate());
       }
@@ -2478,9 +2474,7 @@ void KeyedStoreIC::StoreElementPolymorphicHandlers(
     } else {
       {
         Tagged<Map> tmap = receiver_map->FindElementsKindTransitionedMap(
-            isolate(),
-            MapHandlesSpan(receiver_maps.begin(), receiver_maps.end()),
-            ConcurrencyMode::kSynchronous);
+            isolate(), receiver_maps, ConcurrencyMode::kSynchronous);
         if (!tmap.is_null()) {
           if (receiver_map->is_stable()) {
             receiver_map->NotifyLeafMapLayoutChange(isolate());

deps/v8/src/ic/ic.h

@@ -87,7 +87,7 @@ class IC {
   void ConfigureVectorState(Handle<Name> name, Handle<Map> map,
                             const MaybeObjectHandle& handler);
   // Configure the vector for POLYMORPHIC.
-  void ConfigureVectorState(Handle<Name> name, MapHandlesSpan maps,
+  void ConfigureVectorState(Handle<Name> name, MapHandles const& maps,
                             MaybeObjectHandles* handlers);
   void ConfigureVectorState(
       Handle<Name> name, std::vector<MapAndHandler> const& maps_and_handlers);

deps/v8/src/objects/map.cc

@@ -930,15 +930,16 @@ Handle<Map> Map::GetDerivedMap(Isolate* isolate, Handle<Map> from,
                                                        prototype);
 }
 
-static bool ContainsMap(MapHandlesSpan maps, Tagged<Map> map) {
+static bool ContainsMap(MapHandles const& maps, Tagged<Map> map) {
   DCHECK(!map.is_null());
   for (Handle<Map> current : maps) {
     if (!current.is_null() && *current == map) return true;
   }
   return false;
 }
 
-static bool HasElementsKind(MapHandlesSpan maps, ElementsKind elements_kind) {
+static bool HasElementsKind(MapHandles const& maps,
+                            ElementsKind elements_kind) {
   for (Handle<Map> current : maps) {
     if (!current.is_null() && current->elements_kind() == elements_kind)
       return true;
@@ -947,7 +948,7 @@ static bool HasElementsKind(MapHandlesSpan maps, ElementsKind elements_kind) {
 }
 
 Tagged<Map> Map::FindElementsKindTransitionedMap(Isolate* isolate,
-                                                 MapHandlesSpan candidates,
+                                                 MapHandles const& candidates,
                                                  ConcurrencyMode cmode) {
   DisallowGarbageCollection no_gc;
 

deps/v8/src/objects/map.h

@@ -5,7 +5,6 @@
 #ifndef V8_OBJECTS_MAP_H_
 #define V8_OBJECTS_MAP_H_
 
-#include "include/v8-memory-span.h"
 #include "src/base/bit-field.h"
 #include "src/common/globals.h"
 #include "src/objects/code.h"
@@ -133,7 +132,6 @@ enum class ObjectFields {
 };
 
 using MapHandles = std::vector<Handle<Map>>;
-using MapHandlesSpan = v8::MemorySpan<Handle<Map>>;
 
 #include "torque-generated/src/objects/map-tq.inc"
 
@@ -847,7 +845,7 @@ class Map : public TorqueGeneratedMap<Map, HeapObject> {
   // elements_kind that's found in |candidates|, or |nullptr| if no match is
   // found at all.
   V8_EXPORT_PRIVATE Tagged<Map> FindElementsKindTransitionedMap(
-      Isolate* isolate, MapHandlesSpan candidates, ConcurrencyMode cmode);
+      Isolate* isolate, MapHandles const& candidates, ConcurrencyMode cmode);
 
   inline bool CanTransition() const;
 

deps/v8/test/cctest/test-field-type-tracking.cc

@@ -1840,7 +1840,8 @@ static void TestReconfigureElementsKind_GeneralizeFieldInPlace(
   // Ensure Map::FindElementsKindTransitionedMap() is able to find the
   // transitioned map.
   {
-    Handle<Map> map_list[1]{updated_map};
+    MapHandles map_list;
+    map_list.push_back(updated_map);
     Tagged<Map> transitioned_map = map2->FindElementsKindTransitionedMap(
         isolate, map_list, ConcurrencyMode::kSynchronous);
     CHECK_EQ(*updated_map, transitioned_map);