Reland "In-object double fields unboxing (for 64-bit only)."

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/v8.h"
 
 #include "src/disasm.h"
 #include "src/disassembler.h"
 #include "src/heap/objects-visiting.h"
 #include "src/jsregexp.h"
@@ skipping 215 matching lines @@
 void JSObject::PrintProperties(std::ostream& os) {  // NOLINT
   if (HasFastProperties()) {
     DescriptorArray* descs = map()->instance_descriptors();
     for (int i = 0; i < map()->NumberOfOwnDescriptors(); i++) {
       os << "   ";
       descs->GetKey(i)->NamePrint(os);
       os << ": ";
       switch (descs->GetType(i)) {
         case FIELD: {
           FieldIndex index = FieldIndex::ForDescriptor(map(), i);
-          os << Brief(RawFastPropertyAt(index)) << " (field at offset "
-             << index.property_index() << ")\n";
+          if (IsUnboxedDoubleField(index)) {
+            os << "<unboxed double> " << RawFastDoublePropertyAt(index);
+          } else {
+            os << Brief(RawFastPropertyAt(index));
+          }
+          os << " (field at offset " << index.property_index() << ")\n";
           break;
         }
         case CONSTANT:
           os << Brief(descs->GetConstant(i)) << " (constant)\n";
           break;
         case CALLBACKS:
           os << Brief(descs->GetCallbacksObject(i)) << " (callback)\n";
           break;
         case NORMAL:  // only in slow mode
           UNREACHABLE();
@@ skipping 175 matching lines @@
   if (is_access_check_needed()) os << " - access_check_needed\n";
   if (is_frozen()) {
     os << " - frozen\n";
   } else if (!is_extensible()) {
     os << " - sealed\n";
   }
   os << " - 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());
+  }
   if (HasTransitionArray()) {
     os << "\n - transitions: " << Brief(transitions());
   }
   os << "\n - prototype: " << Brief(prototype());
   os << "\n - constructor: " << Brief(constructor());
   os << "\n - code cache: " << Brief(code_cache());
   os << "\n - dependent code: " << Brief(dependent_code());
   os << "\n";
 }
 
@@ skipping 626 matching lines @@
   os << "Descriptor array " << number_of_descriptors() << "\n";
   for (int i = 0; i < number_of_descriptors(); i++) {
     Descriptor desc;
     Get(i, &desc);
     os << " " << i << ": " << desc << "\n";
   }
   os << "\n";
 }
 
 
+static void PrintBitMask(std::ostream& os, uint32_t value) {  // NOLINT
+  for (int i = 0; i < 32; i++) {
+    if ((i & 7) == 0) os << " ";
+    os << (((value & 1) == 0) ? "_" : "x");
+    value >>= 1;
+  }
+}
+
+
+void LayoutDescriptor::Print() {
+  OFStream os(stdout);
+  this->Print(os);
+  os << std::flush;
+}
+
+
+void LayoutDescriptor::Print(std::ostream& os) {  // NOLINT
+  os << "Layout descriptor: ";
+  if (IsUninitialized()) {
+    os << "<uninitialized>";
+  } else if (IsFastPointerLayout()) {
+    os << "<all tagged>";
+  } else if (IsSmi()) {
+    os << "fast";
+    PrintBitMask(os, static_cast<uint32_t>(Smi::cast(this)->value()));
+  } else {
+    os << "slow";
+    int len = length();
+    for (int i = 0; i < len; i++) {
+      if (i > 0) os << " |";
+      PrintBitMask(os, get_scalar(i));
+    }
+  }
+  os << "\n";
+}
+
+
 void TransitionArray::Print() {
   OFStream os(stdout);
   this->PrintTransitions(os);
   os << std::flush;
 }
 
 
 void TransitionArray::PrintTransitions(std::ostream& os,
                                        bool print_header) {  // NOLINT
   if (print_header) {
@@ skipping 68 matching lines @@
       return SNPrintF(str, "#<%s>", s->PrivateSymbolToName());
     } else {
       return SNPrintF(str, "<%s>", String::cast(s->name())->ToCString().get());
     }
   }
 }
 
 
 #endif  // TRACE_MAPS
 } }  // namespace v8::internal