Guard against undefined fields in global context.

src/heap.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 624 matching lines @@
   // Memory is exhausted and we will die.
   V8::FatalProcessOutOfMemory("Committing semi space failed.");
 }
 
 
 void Heap::ClearJSFunctionResultCaches() {
   if (isolate_->bootstrapper()->IsActive()) return;
 
   Object* context = global_contexts_list_;
   while (!context->IsUndefined()) {
-    // Get the caches for this context:
-    FixedArray* caches =
-      Context::cast(context)->jsfunction_result_caches();
-    // Clear the caches:
-    int length = caches->length();
-    for (int i = 0; i < length; i++) {
-      JSFunctionResultCache::cast(caches->get(i))->Clear();
+    // Get the caches for this context. GC can happen when the context
+    // is not fully initialized, so the caches can be undefined.
+    Object* caches_or_undefined =
+        Context::cast(context)->get(Context::JSFUNCTION_RESULT_CACHES_INDEX);
+    if (!caches_or_undefined->IsUndefined()) {
+      FixedArray* caches = FixedArray::cast(caches_or_undefined);
+      // Clear the caches:
+      int length = caches->length();
+      for (int i = 0; i < length; i++) {
+        JSFunctionResultCache::cast(caches->get(i))->Clear();
+      }
     }
     // Get the next context:
     context = Context::cast(context)->get(Context::NEXT_CONTEXT_LINK);
   }
 }
 
 
 
 void Heap::ClearNormalizedMapCaches() {
   if (isolate_->bootstrapper()->IsActive() &&
       !incremental_marking()->IsMarking()) {
     return;
   }
 
   Object* context = global_contexts_list_;
   while (!context->IsUndefined()) {
-    Context::cast(context)->normalized_map_cache()->Clear();
+    // GC can happen when the context is not fully initialized,
+    // so the cache can be undefined.
+    Object* cache =
+        Context::cast(context)->get(Context::NORMALIZED_MAP_CACHE_INDEX);
+    if (!cache->IsUndefined()) {
+      NormalizedMapCache::cast(cache)->Clear();
+    }
     context = Context::cast(context)->get(Context::NEXT_CONTEXT_LINK);
   }
 }
 
 
 void Heap::UpdateSurvivalRateTrend(int start_new_space_size) {
   double survival_rate =
       (static_cast<double>(young_survivors_after_last_gc_) * 100) /
       start_new_space_size;
 
@@ skipping 5912 matching lines @@
   isolate_->heap()->store_buffer()->Compact();
   isolate_->heap()->store_buffer()->Filter(MemoryChunk::ABOUT_TO_BE_FREED);
   for (chunk = chunks_queued_for_free_; chunk != NULL; chunk = next) {
     next = chunk->next_chunk();
     isolate_->memory_allocator()->Free(chunk);
   }
   chunks_queued_for_free_ = NULL;
 }
 
 } }  // namespace v8::internal