Patch for allowing several V8 instances in process:...

src/platform-linux.cc

 // Copyright 2006-2008 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 149 matching lines @@
 
 
 // We keep the lowest and highest addresses mapped as a quick way of
 // determining that pointers are outside the heap (used mostly in assertions
 // and verification).  The estimate is conservative, ie, not all addresses in
 // 'allocated' space are actually allocated to our heap.  The range is
 // [lowest, highest), inclusive on the low and and exclusive on the high end.
 static void* lowest_ever_allocated = reinterpret_cast<void*>(-1);
 static void* highest_ever_allocated = reinterpret_cast<void*>(0);
 
+static MutexLockAdapter heap_limits_lock(OS::CreateMutex());
 
 static void UpdateAllocatedSpaceLimits(void* address, int size) {
+  V8SharedStateLocker heap_limits_locker(&heap_limits_lock);
   lowest_ever_allocated = Min(lowest_ever_allocated, address);
   highest_ever_allocated =
       Max(highest_ever_allocated,
           reinterpret_cast<void*>(reinterpret_cast<char*>(address) + size));
 }
 
 
 bool OS::IsOutsideAllocatedSpace(void* address) {
+  V8SharedStateLocker heap_limits_locker(&heap_limits_lock);
   return address < lowest_ever_allocated || address >= highest_ever_allocated;
 }
 
 
 size_t OS::AllocateAlignment() {
   return sysconf(_SC_PAGESIZE);
 }
 
 
 void* OS::Allocate(const size_t requested,
@@ skipping 609 matching lines @@
 
   // This sampler is no longer the active sampler.
   active_sampler_ = NULL;
   active_ = false;
 }
 
 
 #endif  // ENABLE_LOGGING_AND_PROFILING
 
 } }  // namespace v8::internal