Generalize map dependent codes array to allow multiple dependency groups.

src/mark-compact.cc

Index: src/mark-compact.cc
diff --git a/src/mark-compact.cc b/src/mark-compact.cc
index 869b318f547572257b66beb0df92c9e32b2ed814..32516845dfdef73a30032fdf179127097a71ca52 100644
--- a/src/mark-compact.cc
+++ b/src/mark-compact.cc
@@ -2369,7 +2369,9 @@ void MarkCompactCollector::ClearNonLiveMapTransitions(Map* map,
 void MarkCompactCollector::ClearAndDeoptimizeDependentCodes(Map* map) {
   AssertNoAllocation no_allocation_scope;
   DependentCodes* codes = map->dependent_codes();
-  int number_of_codes = codes->number_of_codes();
+  DependentCodes::GroupStartIndexes starts;
+  codes->ComputeGroupStartIndexes(starts);
+  int number_of_codes = starts[DependentCodes::kGroupCount];
   if (number_of_codes == 0) return;
   for (int i = 0; i < number_of_codes; i++) {
     Code* code = codes->code_at(i);
@@ -2385,24 +2387,33 @@ void MarkCompactCollector::ClearAndDeoptimizeDependentCodes(Map* map) {
 void MarkCompactCollector::ClearNonLiveDependentCodes(Map* map) {
   AssertNoAllocation no_allocation_scope;
   DependentCodes* codes = map->dependent_codes();
-  int number_of_codes = codes->number_of_codes();
+  DependentCodes::GroupStartIndexes starts;
+  codes->ComputeGroupStartIndexes(starts);
+  int number_of_codes = starts[DependentCodes::kGroupCount];
   if (number_of_codes == 0) return;
   int new_number_of_codes = 0;
-  for (int i = 0; i < number_of_codes; i++) {
-    Code* code = codes->code_at(i);
-    if (IsMarked(code) && !code->marked_for_deoptimization()) {
-      if (new_number_of_codes != i) {
-        codes->set_code_at(new_number_of_codes, code);
+  // Go through all groups, remove dead codes and compact.
+  for (int g = 0; g < DependentCodes::kGroupCount; g++) {
+    int group_number_of_codes = 0;
+    for (int i = starts[g]; i < starts[g + 1]; i++) {
+      Code* code = codes->code_at(i);
+      if (IsMarked(code) && !code->marked_for_deoptimization()) {
+        if (new_number_of_codes + group_number_of_codes != i) {
+          codes->set_code_at(new_number_of_codes + group_number_of_codes, code);
+        }
+        Object** slot = codes->code_slot_at(new_number_of_codes +
+                                            group_number_of_codes);
+        RecordSlot(slot, slot, code);
+        group_number_of_codes++;
       }
-      Object** slot = codes->code_slot_at(new_number_of_codes);
-      RecordSlot(slot, slot, code);
-      new_number_of_codes++;
     }
+    codes->set_number_of_codes(static_cast<DependentCodes::DependencyGroup>(g),
+                               group_number_of_codes);
+    new_number_of_codes += group_number_of_codes;
   }
   for (int i = new_number_of_codes; i < number_of_codes; i++) {
     codes->clear_code_at(i);
   }
-  codes->set_number_of_codes(new_number_of_codes);
 }