Fix iterator (std::vector) invalidation during sampling heap profile retrieval

src/profiler/sampling-heap-profiler.cc

 // Copyright 2015 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/profiler/sampling-heap-profiler.h"
 
 #include <stdint.h>
 #include <memory>
 #include "src/api.h"
 #include "src/base/utils/random-number-generator.h"
@@ skipping 205 matching lines @@
       allocations.push_back(ScaleSample(alloc.first, alloc.second));
     }
   }
 
   profile->nodes().push_back(v8::AllocationProfile::Node(
       {ToApiHandle<v8::String>(
            isolate_->factory()->InternalizeUtf8String(node->name_)),
        script_name, node->script_id_, node->script_position_, line, column,
        std::vector<v8::AllocationProfile::Node*>(), allocations}));
   v8::AllocationProfile::Node* current = &profile->nodes().back();
-  for (auto child : node->children_) {
+  size_t child_len = node->children_.size();
+  // The children vector may have nodes appended to it during translation
+  // because the translation may allocate strings on the JS heap that have
+  // the potential to be sampled. We cache the length of the vector before
+  // iteration so that nodes appended to the vector during iteration are
+  // not processed.
+  for (size_t i = 0; i < child_len; i++) {
     current->children.push_back(
-        TranslateAllocationNode(profile, child, scripts));
+        TranslateAllocationNode(profile, node->children_[i], scripts));
   }
   return current;
 }
 
 v8::AllocationProfile* SamplingHeapProfiler::GetAllocationProfile() {
   // To resolve positions to line/column numbers, we will need to look up
   // scripts. Build a map to allow fast mapping from script id to script.
   std::map<int, Script*> scripts;
   {
     Script::Iterator iterator(isolate_);
     Script* script;
     while ((script = iterator.Next())) {
       scripts[script->id()] = script;
     }
   }
 
   auto profile = new v8::internal::AllocationProfile();
 
   TranslateAllocationNode(profile, &profile_root_, scripts);
 
   return profile;
 }
 
 
 }  // namespace internal
 }  // namespace v8