Dump information when we hit a FATAL in become

runtime/vm/become.cc

 // Copyright (c) 2016, 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/become.h"
 
 #include "platform/assert.h"
 #include "platform/utils.h"
 
 #include "vm/dart_api_state.h"
@@ skipping 174 matching lines @@
   ForwardObjectTo(instance.raw(), instance.raw());
 }
 
 
 static bool IsDummyObject(RawObject* object) {
   if (!object->IsForwardingCorpse()) return false;
   return GetForwardedObject(object) == object;
 }
 
 
+void Become::CrashDump(RawObject* before_obj, RawObject* after_obj) {
+  OS::PrintErr("DETECTED FATAL ISSUE IN BECOME MAPPINGS\n");
+
+  OS::PrintErr("BEFORE ADDRESS: %p\n", before_obj);
+  OS::PrintErr("BEFORE IS HEAP OBJECT: %s",
+               before_obj->IsHeapObject() ? "YES" : "NO");
+  OS::PrintErr("BEFORE IS VM HEAP OBJECT: %s",
+               before_obj->IsVMHeapObject() ? "YES" : "NO");
+
+  OS::PrintErr("AFTER ADDRESS: %p\n", after_obj);
+  OS::PrintErr("AFTER IS HEAP OBJECT: %s",
+               after_obj->IsHeapObject() ? "YES" : "NO");
+  OS::PrintErr("AFTER IS VM HEAP OBJECT: %s",
+               after_obj->IsVMHeapObject() ? "YES" : "NO");
+
+  if (before_obj->IsHeapObject()) {
+    OS::PrintErr("BEFORE OBJECT CLASS ID=%" Pd "\n", before_obj->GetClassId());
+    const Object& obj = Object::Handle(before_obj);
+    OS::PrintErr("BEFORE OBJECT AS STRING=%s\n", obj.ToCString());
+  }
+
+  if (after_obj->IsHeapObject()) {
+    OS::PrintErr("AFTER OBJECT CLASS ID=%" Pd "\n", after_obj->GetClassId());
+    const Object& obj = Object::Handle(after_obj);
+    OS::PrintErr("AFTER OBJECT AS STRING=%s\n", obj.ToCString());
+  }
+}
+
+
 void Become::ElementsForwardIdentity(const Array& before, const Array& after) {
   Thread* thread = Thread::Current();
   Isolate* isolate = thread->isolate();
   Heap* heap = isolate->heap();
 
   TIMELINE_FUNCTION_GC_DURATION(thread, "Become::ElementsForwardIdentity");
   HeapIterationScope his;
 
   // Setup forwarding pointers.
   ASSERT(before.Length() == after.Length());
   for (intptr_t i = 0; i < before.Length(); i++) {
     RawObject* before_obj = before.At(i);
     RawObject* after_obj = after.At(i);
 
     if (before_obj == after_obj) {
       FATAL("become: Cannot self-forward");
     }
     if (!before_obj->IsHeapObject()) {
+      CrashDump(before_obj, after_obj);
       FATAL("become: Cannot forward immediates");
     }
     if (!after_obj->IsHeapObject()) {
-      FATAL("become: Cannot become an immediates");
+      CrashDump(before_obj, after_obj);
+      FATAL("become: Cannot become immediates");
     }
     if (before_obj->IsVMHeapObject()) {
+      CrashDump(before_obj, after_obj);
       FATAL("become: Cannot forward VM heap objects");
     }
     if (before_obj->IsForwardingCorpse() && !IsDummyObject(before_obj)) {
       FATAL("become: Cannot forward to multiple targets");
     }
     if (after_obj->IsForwardingCorpse()) {
       // The Smalltalk become does allow this, and for very special cases
       // it is important (shape changes to Class or Mixin), but as these
       // cases do not arise in Dart, better to prohibit it.
       FATAL("become: No indirect chains of forwarding");
@@ skipping 30 matching lines @@
   }
 
 #if defined(DEBUG)
   for (intptr_t i = 0; i < before.Length(); i++) {
     ASSERT(before.At(i) == after.At(i));
   }
 #endif
 }
 
 }  // namespace dart