Verify/document assumption about stack resource addresses.

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 "platform/address_sanitizer.h"
 
 #include "vm/dart_api_impl.h"
 #include "vm/dart_entry.h"
@@ skipping 268 matching lines @@
   Simulator::Current()->Longjmp(program_counter, stack_pointer, frame_pointer,
                                 raw_exception, raw_stacktrace, isolate);
 #else
   // Prepare for unwinding frames by destroying all the stack resources
   // in the previous frames.
 
   while (isolate->top_resource() != NULL &&
          (reinterpret_cast<uword>(isolate->top_resource()) < stack_pointer)) {
     isolate->top_resource()->~StackResource();
   }
+#if defined(DEBUG)
+  // All remaining stack resources should be below stack_pointer.
+  StackResource* current = isolate->top_resource();
+  while (current != NULL) {
+    ASSERT(reinterpret_cast<uword>(current) > stack_pointer);

[zra, 2015/02/17 19:00:23]

Is this the only place where this assertion is needed? Do we walk the stack
resources and reclaim anywhere else?

[koda, 2015/02/17 19:07:54]

Yes, we do the same thing in the simulators. We should share the code. I'll send
out an updated CL.

+    current = current->previous();
+  }
+#endif  // DEBUG
 
   // Call a stub to set up the exception object in kExceptionObjectReg,
   // to set up the stacktrace object in kStackTraceObjectReg, and to
   // continue execution at the given pc in the given frame.
   typedef void (*ExcpHandler)(uword, uword, uword, RawObject*, RawObject*,
                               Isolate*);
   ExcpHandler func = reinterpret_cast<ExcpHandler>(
       StubCode::JumpToExceptionHandlerEntryPoint());
 
   // Unpoison the stack before we tear it down in the generated stub code.
@@ skipping 455 matching lines @@
 
 // Throw JavascriptCompatibilityError exception.
 void Exceptions::ThrowJavascriptCompatibilityError(const char* msg) {
   const Array& exc_args = Array::Handle(Array::New(1));
   const String& msg_str = String::Handle(String::New(msg));
   exc_args.SetAt(0, msg_str);
   Exceptions::ThrowByType(Exceptions::kJavascriptCompatibilityError, exc_args);
 }
 
 }  // namespace dart