[logging] Enable basic --trace-maps by default

This CL makes --trace-maps available in the default build by disabling
certain expensive/intrusive features.

This is an intermediate step to be able to write proper tests for --trace-maps
and the new map-processor.

Change-Id: Ib6a8fc9c77796c106d3af9d741d48abe6c6b9099
Reviewed-on: https://chromium-review.googlesource.com/734648
Reviewed-by: Adam Klein <adamk@chromium.org>
Commit-Queue: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#48891}

src/bootstrapper.cc

@@ -5376,15 +5376,16 @@ Genesis::Genesis(
     AddToWeakNativeContextList(*native_context());
     isolate->set_context(*native_context());
     isolate->counters()->contexts_created_by_snapshot()->Increment();
-#if V8_TRACE_MAPS
     if (FLAG_trace_maps) {
       Handle<JSFunction> object_fun = isolate->object_function();
+      int sfi_id = -1;
+#if V8_SFI_HAS_UNIQUE_ID
+      sfi_id = object_fun->shared()->unique_id();
+#endif  // V8_SFI_HAS_UNIQUE_ID
       PrintF("[TraceMap: InitialMap map= %p SFI= %d_Object ]\n",
-             reinterpret_cast<void*>(object_fun->initial_map()),
+             reinterpret_cast<void*>(object_fun->initial_map()), sfi_id);
-             object_fun->shared()->unique_id());
       Map::TraceAllTransitions(object_fun->initial_map());
     }
-#endif
 
     if (context_snapshot_index == 0) {
       Handle<JSGlobalObject> global_object =

src/flag-definitions.h

@@ -868,9 +868,7 @@ DEFINE_BOOL(trace_prototype_users, false,
             "Trace updates to prototype user tracking")
 DEFINE_BOOL(use_verbose_printer, true, "allows verbose printing")
 DEFINE_BOOL(trace_for_in_enumerate, false, "Trace for-in enumerate slow-paths")
-#if V8_TRACE_MAPS
 DEFINE_BOOL(trace_maps, false, "trace map creation")
-#endif
 
 // parser.cc
 DEFINE_BOOL(allow_natives_syntax, false, "allow natives syntax")

src/objects-printer.cc

@@ -1611,8 +1611,7 @@ void PreParsedScopeData::PreParsedScopeDataPrint(std::ostream& os) {  // NOLINT
 
 #endif  // OBJECT_PRINT
 
-#if V8_TRACE_MAPS
+// TODO(cbruni): remove once the new maptracer is in place.
-
 void Name::NameShortPrint() {
   if (this->IsString()) {
     PrintF("%s", String::cast(this)->ToCString().get());
@@ -1627,7 +1626,7 @@ void Name::NameShortPrint() {
   }
 }
 
-
+// TODO(cbruni): remove once the new maptracer is in place.
 int Name::NameShortPrint(Vector<char> str) {
   if (this->IsString()) {
     return SNPrintF(str, "%s", String::cast(this)->ToCString().get());
@@ -1642,8 +1641,6 @@ int Name::NameShortPrint(Vector<char> str) {
   }
 }
 
-#endif  // V8_TRACE_MAPS
-
 #if defined(DEBUG) || defined(OBJECT_PRINT)
 // This method is only meant to be called from gdb for debugging purposes.
 // Since the string can also be in two-byte encoding, non-Latin1 characters

src/objects.cc

@@ -6245,13 +6245,11 @@ void JSObject::MigrateSlowToFast(Handle<JSObject> object,
 
   NotifyMapChange(old_map, new_map, isolate);
 
-#if V8_TRACE_MAPS
   if (FLAG_trace_maps) {
     PrintF("[TraceMaps: SlowToFast from= %p to= %p reason= %s ]\n",
            reinterpret_cast<void*>(*old_map), reinterpret_cast<void*>(*new_map),
            reason);
   }
-#endif
 
   if (instance_descriptor_length == 0) {
     DisallowHeapAllocation no_gc;
@@ -9092,13 +9090,11 @@ Handle<Map> Map::Normalize(Handle<Map> fast_map, PropertyNormalizationMode mode,
       cache->Set(fast_map, new_map, cell);
       isolate->counters()->maps_normalized()->Increment();
     }
-#if V8_TRACE_MAPS
     if (FLAG_trace_maps) {
       PrintF("[TraceMaps: Normalize from= %p to= %p reason= %s ]\n",
              reinterpret_cast<void*>(*fast_map),
              reinterpret_cast<void*>(*new_map), reason);
     }
-#endif
   }
   fast_map->NotifyLeafMapLayoutChange();
   return new_map;
@@ -9263,8 +9259,6 @@ Handle<Map> Map::ShareDescriptor(Handle<Map> map,
   return result;
 }
 
-#if V8_TRACE_MAPS
-
 // static
 void Map::TraceTransition(const char* what, Map* from, Map* to, Name* name) {
   if (FLAG_trace_maps) {
@@ -9289,8 +9283,6 @@ void Map::TraceAllTransitions(Map* map) {
   }
 }
 
-#endif  // V8_TRACE_MAPS
-
 void Map::ConnectTransition(Handle<Map> parent, Handle<Map> child,
                             Handle<Name> name, SimpleTransitionFlag flag) {
   Isolate* isolate = parent->GetIsolate();
@@ -9314,14 +9306,10 @@ void Map::ConnectTransition(Handle<Map> parent, Handle<Map> child,
   }
   if (parent->is_prototype_map()) {
     DCHECK(child->is_prototype_map());
-#if V8_TRACE_MAPS
     Map::TraceTransition("NoTransition", *parent, *child, *name);
-#endif
   } else {
     TransitionsAccessor(parent).Insert(name, child, flag);
-#if V8_TRACE_MAPS
     Map::TraceTransition("Transition", *parent, *child, *name);
-#endif
   }
 }
 
@@ -9356,7 +9344,6 @@ Handle<Map> Map::CopyReplaceDescriptors(
   } else {
     result->InitializeDescriptors(*descriptors, *layout_descriptor);
   }
-#if V8_TRACE_MAPS
   if (FLAG_trace_maps &&
       // Mirror conditions above that did not call ConnectTransition().
       (map->is_prototype_map() ||
@@ -9366,8 +9353,6 @@ Handle<Map> Map::CopyReplaceDescriptors(
            reinterpret_cast<void*>(*map), reinterpret_cast<void*>(*result),
            reason);
   }
-#endif
-
   return result;
 }
 
@@ -9553,13 +9538,11 @@ Handle<Map> Map::CopyForTransition(Handle<Map> map, const char* reason) {
     new_map->InitializeDescriptors(*new_descriptors, *new_layout_descriptor);
   }
 
-#if V8_TRACE_MAPS
   if (FLAG_trace_maps) {
     PrintF("[TraceMaps: CopyForTransition from= %p to= %p reason= %s ]\n",
            reinterpret_cast<void*>(*map), reinterpret_cast<void*>(*new_map),
            reason);
   }
-#endif
 
   return new_map;
 }
@@ -12810,13 +12793,15 @@ void JSFunction::SetInitialMap(Handle<JSFunction> function, Handle<Map> map,
   if (map->prototype() != *prototype) Map::SetPrototype(map, prototype);
   function->set_prototype_or_initial_map(*map);
   map->SetConstructor(*function);
-#if V8_TRACE_MAPS
   if (FLAG_trace_maps) {
+    int sfi_id = -1;
+#if V8_SFI_HAS_UNIQUE_ID
+    sfi_id = function->shared()->unique_id();
+#endif  // V8_SFI_HAS_UNIQUE_ID
     PrintF("[TraceMaps: InitialMap map= %p SFI= %d_%s ]\n",
-           reinterpret_cast<void*>(*map), function->shared()->unique_id(),
+           reinterpret_cast<void*>(*map), sfi_id,
            function->shared()->DebugName()->ToCString().get());
   }
-#endif
 }
 
 

src/objects/map.h

@@ -837,10 +837,8 @@ class Map : public HeapObject {
   // Returns true if given field is unboxed double.
   inline bool IsUnboxedDoubleField(FieldIndex index) const;
 
-#if V8_TRACE_MAPS
   static void TraceTransition(const char* what, Map* from, Map* to, Name* name);
   static void TraceAllTransitions(Map* map);
-#endif
 
   static inline Handle<Map> AddMissingTransitionsForTesting(
       Handle<Map> split_map, Handle<DescriptorArray> descriptors,

src/objects/name.h

@@ -57,10 +57,8 @@ class Name : public HeapObject {
   DECL_CAST(Name)
 
   DECL_PRINTER(Name)
-#if V8_TRACE_MAPS
   void NameShortPrint();
   int NameShortPrint(Vector<char> str);
-#endif
 
   // Layout description.
   static const int kHashFieldSlot = HeapObject::kHeaderSize;
@@ -188,9 +186,8 @@ class Symbol : public Name {
  private:
   const char* PrivateSymbolToName() const;
 
-#if V8_TRACE_MAPS
+  // TODO(cbruni): remove once the new maptracer is in place.
   friend class Name;  // For PrivateSymbolToName.
-#endif
 
   DISALLOW_IMPLICIT_CONSTRUCTORS(Symbol);
 };