Improve behaviour when we hit a stack overflow / OOM error

runtime/vm/object.cc

 // Copyright (c) 2012, 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/object.h"
 
 #include "include/dart_api.h"
 #include "platform/assert.h"
 #include "vm/assembler.h"
 #include "vm/cpu.h"
@@ skipping 21061 matching lines @@
   Zone* zone = Thread::Current()->zone();
   Function& function = Function::Handle();
   Code& code = Code::Handle();
   // Iterate through the stack frames and create C string description
   // for each frame.
   intptr_t total_len = 0;
   GrowableArray<char*> frame_strings;
   for (intptr_t i = 0; (i < Length()) && (*frame_index < max_frames); i++) {
     function = FunctionAtFrame(i);
     if (function.IsNull()) {
-      // Check if null function object indicates a gap in a StackOverflow or
+      // Check for a null function, which indicates a gap in a StackOverflow or
       // OutOfMemory trace.
       if ((i < (Length() - 1)) &&
           (FunctionAtFrame(i + 1) != Function::null())) {
         const char* kTruncated = "...\n...\n";
         intptr_t truncated_len = strlen(kTruncated) + 1;
         char* chars = zone->Alloc<char>(truncated_len);
         OS::SNPrint(chars, truncated_len, "%s", kTruncated);
         frame_strings.Add(chars);
         total_len += truncated_len;
+        ASSERT(PcOffsetAtFrame(i) != Smi::null());
+        // To account for gap frames.
+        (*frame_index) += Smi::Value(PcOffsetAtFrame(i));
       }
     } else {
       code = CodeAtFrame(i);
       ASSERT(function.raw() == code.function());
       uword pc = code.EntryPoint() + Smi::Value(PcOffsetAtFrame(i));
       if (code.is_optimized() && expand_inlined()) {
         // Traverse inlined frames.
         if (!FLAG_precompilation) {
           for (InlinedFunctionsIterator it(code, pc);
                !it.Done() && (*frame_index < max_frames); it.Advance()) {
@@ skipping 360 matching lines @@
   return UserTag::null();
 }
 
 
 const char* UserTag::ToCString() const {
   const String& tag_label = String::Handle(label());
   return tag_label.ToCString();
 }
 
 }  // namespace dart