Provide a mechanism for dumping of heap profiles on predefined events.

runtime/vm/exceptions.cc

 // Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 #include "vm/exceptions.h"
 
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
 #include "vm/debugger.h"
 #include "vm/flags.h"
 #include "vm/object.h"
+#include "vm/object_store.h"
 #include "vm/stack_frame.h"
 #include "vm/stub_code.h"
 #include "vm/symbols.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, print_stacktrace_at_throw, false,
-    "Prints a stack trace everytime a throw occurs.");
+            "Prints a stack trace everytime a throw occurs.");
+DEFINE_FLAG(bool, heap_profile_out_of_memory, false,
+            "Writes a heap profile on unhandled out-of-memory exceptions.");
 
 
 const char* Exceptions::kCastErrorDstName = "type cast";
 
 
 // Iterate through the stack frames and try to find a frame with an
 // exception handler. Once found, set the pc, sp and fp so that execution
 // can continue in that frame.
 static bool FindExceptionHandler(uword* handler_pc,
                                  uword* handler_sp,
@@ skipping 129 matching lines @@
   bool handler_exists = FindExceptionHandler(&handler_pc,
                                              &handler_sp,
                                              &handler_fp,
                                              func_list,
                                              code_list,
                                              pc_offset_list);
   if (handler_pc == 0) {
     // There are no dart invocation frames on the stack so we do not
     // have a caller to return to.
     ASSERT(!handler_exists);
+    if (FLAG_heap_profile_out_of_memory) {
+      Isolate* isolate = Isolate::Current();
+      Instance& out_of_memory =
+          Instance::Handle(isolate->object_store()->out_of_memory());
+      if (incoming_exception.Equals(out_of_memory)) {
+        Instance& out_of_memory =
+            Instance::Handle(isolate->object_store()->out_of_memory());
+        if (incoming_exception.Equals(out_of_memory)) {

[siva, 2012/12/07 00:33:02]

The handle and if check seems to be repeated twice here?

[cshapiro, 2012/12/08 07:29:46]

Sorry about that.  I actually caught this earlier.  Removed.

+          const char* format = "%s-out-of-memory.hprof";
+          intptr_t len = OS::SNPrint(NULL, 0, format, isolate->name());
+          char* filename = isolate->current_zone()->Alloc<char>(len + 1);
+          OS::SNPrint(filename, len + 1, format, isolate->name());
+          isolate->heap()->ProfileToFile(filename);

[siva, 2012/12/07 00:33:02]

Why not change the signature of ProfileToFile to be
void ProfileToFile(const char* suffix_name) const;

That way you could move all the filename computation code into ProfileToFile and
not have have to repeat it in two places.

e.g:

isolate->heap()->ProfileToFile("isolate-initialize");
isolate->heap()->ProfileToFile("isolate-out-of-memory");

[cshapiro, 2012/12/08 07:29:46]

Good idea.  Done.  (Saves ~3 places, actually.)

+        }
+      }
+    }
     if (Isolate::UnhandledExceptionCallback() != NULL) {
       // Notify embedder that an unhandled exception occurred.
       Dart_EnterScope();
       Dart_Handle error_handle = Api::NewHandle(Isolate::Current(),
                                                 incoming_exception.raw());
       (Isolate::UnhandledExceptionCallback())(error_handle);
       Dart_ExitScope();
     } else {
       OS::PrintErr("Exception '%s' thrown:\n", exception.ToCString());
       OS::PrintErr("Shutting down the isolate\n");
@@ skipping 266 matching lines @@
     case kIsolateSpawn:
       library = Library::IsolateLibrary();
       class_name = Symbols::New("IsolateSpawnException");
       break;
   }
 
   return DartLibraryCalls::ExceptionCreate(library, class_name, arguments);
 }
 
 }  // namespace dart