Backport hash collision workaround to 3.6.

src/profile-generator.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 // Redistribution and use in source and binary forms, with or without
 // modification, are permitted provided that the following conditions are
 // met:
 //
 //     * Redistributions of source code must retain the above copyright
 //       notice, this list of conditions and the following disclaimer.
 //     * Redistributions in binary form must reproduce the above
 //       copyright notice, this list of conditions and the following
 //       disclaimer in the documentation and/or other materials provided
@@ skipping 92 matching lines @@
     DeleteArray(reinterpret_cast<const char*>(p->value));
   }
 }
 
 
 const char* StringsStorage::GetCopy(const char* src) {
   int len = static_cast<int>(strlen(src));
   Vector<char> dst = Vector<char>::New(len + 1);
   OS::StrNCpy(dst, src, len);
   dst[len] = '\0';
-  uint32_t hash = HashSequentialString(dst.start(), len);
+  uint32_t hash =
+      HashSequentialString(dst.start(), len, HEAP->StringHashSeed());
   return AddOrDisposeString(dst.start(), hash);
 }
 
 
 const char* StringsStorage::GetFormatted(const char* format, ...) {
   va_list args;
   va_start(args, format);
   const char* result = GetVFormatted(format, args);
   va_end(args);
   return result;
@@ skipping 12 matching lines @@
 }
 
 
 const char* StringsStorage::GetVFormatted(const char* format, va_list args) {
   Vector<char> str = Vector<char>::New(1024);
   int len = OS::VSNPrintF(str, format, args);
   if (len == -1) {
     DeleteArray(str.start());
     return format;
   }
-  uint32_t hash = HashSequentialString(str.start(), len);
+  uint32_t hash = HashSequentialString(
+      str.start(), len, HEAP->StringHashSeed());
   return AddOrDisposeString(str.start(), hash);
 }
 
 
 const char* StringsStorage::GetName(String* name) {
   if (name->IsString()) {
     return AddOrDisposeString(
         name->ToCString(DISALLOW_NULLS, ROBUST_STRING_TRAVERSAL).Detach(),
         name->Hash());
   }
@@ skipping 1298 matching lines @@
         raw_entry, AddressHash(reinterpret_cast<Address>(raw_entry)));
   }
   delete entries_;
   entries_ = new_entries;
 }
 
 
 uint64_t HeapObjectsMap::GenerateId(v8::RetainedObjectInfo* info) {
   uint64_t id = static_cast<uint64_t>(info->GetHash());
   const char* label = info->GetLabel();
-  id ^= HashSequentialString(label, static_cast<int>(strlen(label)));
+  id ^= HashSequentialString(label,
+                             static_cast<int>(strlen(label)),
+                             HEAP->StringHashSeed());
   intptr_t element_count = info->GetElementCount();
   if (element_count != -1)
     id ^= ComputeIntegerHash(static_cast<uint32_t>(element_count));
   return id << 1;
 }
 
 
 HeapSnapshotsCollection::HeapSnapshotsCollection()
     : is_tracking_objects_(false),
       snapshots_uids_(HeapSnapshotsMatch),
@@ skipping 1873 matching lines @@
 
 
 void HeapSnapshotJSONSerializer::SortHashMap(
     HashMap* map, List<HashMap::Entry*>* sorted_entries) {
   for (HashMap::Entry* p = map->Start(); p != NULL; p = map->Next(p))
     sorted_entries->Add(p);
   sorted_entries->Sort(SortUsingEntryValue);
 }
 
 } }  // namespace v8::internal