Gracefully handle unloaded scripts

test/cctest/test-heap-profiler.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 2854 matching lines @@
       v8::String::Utf8Value child_name(child->name);
       if (strcmp(*child_name, name) == 0) {
         node = child;
         break;
       }
     }
   }
   return node;
 }
 
-
 TEST(SamplingHeapProfiler) {
   v8::HandleScope scope(v8::Isolate::GetCurrent());
   LocalContext env;
   v8::HeapProfiler* heap_profiler = env->GetIsolate()->GetHeapProfiler();
 
   // Turn off always_opt. Inlining can cause stack traces to be shorter than
   // what we expect in this test.
   v8::internal::FLAG_always_opt = false;
 
   // Suppress randomness to avoid flakiness in tests.
   v8::internal::FLAG_sampling_heap_profiler_suppress_randomness = true;
 
   const char* script_source =
       "var A = [];\n"
       "function bar(size) { return new Array(size); }\n"
       "var foo = function() {\n"
       "  for (var i = 0; i < 1024; ++i) {\n"
       "    A[i] = bar(1024);\n"
       "  }\n"
       "}\n"
       "foo();";
 
+  const char* gced =

[ofrobots, 2016/03/30 22:35:35]

Use a more descriptive name or, better, inline the script source below at the
only use of this variable.

[mattloring, 2016/03/30 23:55:09]

Done.

+      "for (var i = 0; i < 1024; i++) {\n"
+      "  eval(\"new Array(100)\");\n"
+      "}\n";
+
   // Sample should be empty if requested before sampling has started.
   {
     v8::AllocationProfile* profile = heap_profiler->GetAllocationProfile();
     CHECK(profile == nullptr);
   }
 
   int count_1024 = 0;
   {
     heap_profiler->StartSamplingHeapProfiler(1024);
     CompileRun(script_source);
@@ skipping 70 matching lines @@
         *profile, Vector<const char*>(names1, arraysize(names1)));
     CHECK(node1);
 
     const char* names2[] = {"", "generateFunctions"};
     auto node2 = FindAllocationProfileNode(
         *profile, Vector<const char*>(names2, arraysize(names2)));
     CHECK(node2);
 
     heap_profiler->StopSamplingHeapProfiler();
   }
+
+  // A test case with scripts unloaded before profile gathered
+  {
+    heap_profiler->StartSamplingHeapProfiler(64);
+    CompileRun(gced);
+
+    CcTest::heap()->CollectAllGarbage();
+
+    v8::base::SmartPointer<v8::AllocationProfile> profile(
+        heap_profiler->GetAllocationProfile());
+    CHECK(!profile.is_empty());
+
+    heap_profiler->StopSamplingHeapProfiler();
+  }
 }
 
 
 TEST(SamplingHeapProfilerApiAllocation) {
   v8::HandleScope scope(v8::Isolate::GetCurrent());
   LocalContext env;
   v8::HeapProfiler* heap_profiler = env->GetIsolate()->GetHeapProfiler();
 
   // Suppress randomness to avoid flakiness in tests.
   v8::internal::FLAG_sampling_heap_profiler_suppress_randomness = true;
 
   heap_profiler->StartSamplingHeapProfiler(256);
 
   for (int i = 0; i < 8 * 1024; ++i) v8::Object::New(env->GetIsolate());
 
   v8::base::SmartPointer<v8::AllocationProfile> profile(
       heap_profiler->GetAllocationProfile());
   CHECK(!profile.is_empty());
   const char* names[] = {"(V8 API)"};
   auto node = FindAllocationProfileNode(
       *profile, Vector<const char*>(names, arraysize(names)));
   CHECK(node);
 
   heap_profiler->StopSamplingHeapProfiler();
 }