[printing] Print properties backing store value and add a gdb macro for printing LayoutDescriptors.

src/objects-printer.cc

 // Copyright 2012 the V8 project authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.
 
 #include "src/objects.h"
 
 #include <iomanip>
 #include <memory>
 
 #include "src/disasm.h"
@@ skipping 493 matching lines @@
   }
   os << "]";
   if (obj->GetInternalFieldCount() > 0) {
     os << "\n - internal fields: " << obj->GetInternalFieldCount();
   }
 }
 
 
 static void JSObjectPrintBody(std::ostream& os, JSObject* obj,  // NOLINT
                               bool print_elements = true) {
-  os << "\n - properties = {";
+  os << "\n - properties = " << Brief(obj->properties()) << " {";
   obj->PrintProperties(os);
   os << "\n }\n";
   if (print_elements && obj->elements()->length() > 0) {
     os << " - elements = {";
     obj->PrintElements(os);
     os << "\n }\n";
   }
   int internal_fields = obj->GetInternalFieldCount();
   if (internal_fields > 0) {
     os << " - internal fields = {";
@@ skipping 65 matching lines @@
   if (is_prototype_map()) {
     os << "\n - prototype_map";
     os << "\n - prototype info: " << Brief(prototype_info());
   } else {
     os << "\n - back pointer: " << Brief(GetBackPointer());
   }
   os << "\n - instance descriptors " << (owns_descriptors() ? "(own) " : "")
      << "#" << NumberOfOwnDescriptors() << ": "
      << Brief(instance_descriptors());
   if (FLAG_unbox_double_fields) {
-    os << "\n - layout descriptor: " << Brief(layout_descriptor());
+    os << "\n - layout descriptor: ";
+    layout_descriptor()->ShortPrint(os);
   }
   int nof_transitions = TransitionArray::NumberOfTransitions(raw_transitions());
   if (nof_transitions > 0) {
     os << "\n - transitions #" << nof_transitions << ": "
        << Brief(raw_transitions());
     TransitionArray::PrintTransitions(os, raw_transitions(), false);
   }
   os << "\n - prototype: " << Brief(prototype());
   os << "\n - constructor: " << Brief(GetConstructor());
   os << "\n - code cache: " << Brief(code_cache());
@@ skipping 831 matching lines @@
   }
 }
 
 
 void LayoutDescriptor::Print() {
   OFStream os(stdout);
   this->Print(os);
   os << std::flush;
 }
 
+void LayoutDescriptor::ShortPrint(std::ostream& os) {
+  if (IsSmi()) {
+    os << this;  // Print tagged value for easy use with "jld" gdb macro.
+  } else {
+    os << Brief(this);
+  }
+}
 
 void LayoutDescriptor::Print(std::ostream& os) {  // NOLINT
   os << "Layout descriptor: ";
-  if (IsOddball() && IsUninitialized(HeapObject::cast(this)->GetIsolate())) {
-    os << "<uninitialized>";
-  } else if (IsFastPointerLayout()) {
+  if (IsFastPointerLayout()) {
     os << "<all tagged>";
   } else if (IsSmi()) {
     os << "fast";
     PrintBitMask(os, static_cast<uint32_t>(Smi::cast(this)->value()));
+  } else if (IsOddball() &&
+             IsUninitialized(HeapObject::cast(this)->GetIsolate())) {
+    os << "<uninitialized>";
   } else {
     os << "slow";
     int len = length();
     for (int i = 0; i < len; i++) {
       if (i > 0) os << " |";
       PrintBitMask(os, get_scalar(i));
     }
   }
   os << "\n";
 }
@@ skipping 159 matching lines @@
 }
 
 extern void _v8_internal_Print_DescriptorArray(void* object) {
   if (reinterpret_cast<i::Object*>(object)->IsSmi()) {
     printf("Not a descriptor array\n");
   } else {
     reinterpret_cast<i::DescriptorArray*>(object)->Print();
   }
 }
 
+extern void _v8_internal_Print_LayoutDescriptor(void* object) {
+  i::Object* o = reinterpret_cast<i::Object*>(object);
+  if (!o->IsLayoutDescriptor()) {
+    printf("Not a layout descriptor\n");
+  } else {
+    reinterpret_cast<i::LayoutDescriptor*>(object)->Print();
+  }
+}
+
 extern void _v8_internal_Print_TransitionArray(void* object) {
   if (reinterpret_cast<i::Object*>(object)->IsSmi()) {
     printf("Not a transition array\n");
   } else {
     reinterpret_cast<i::TransitionArray*>(object)->Print();
   }
 }
 
 extern void _v8_internal_Print_StackTrace() {
   i::Isolate* isolate = i::Isolate::Current();
   isolate->PrintStack(stdout);
 }