Support stacktrace and objecthistogram service commands

runtime/vm/heap_histogram.cc

 // Copyright (c) 2013, 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/heap_histogram.h"
 
 #include "platform/assert.h"
 #include "vm/flags.h"
 #include "vm/object.h"
+#include "vm/json_stream.h"
 
 namespace dart {
 
 DEFINE_FLAG(bool, print_object_histogram, false,
             "Print average object histogram at isolate shutdown");
 
 class ObjectHistogramVisitor : public ObjectVisitor {
  public:
   explicit ObjectHistogramVisitor(Isolate* isolate) : ObjectVisitor(isolate) { }
 
@@ skipping 11 matching lines @@
   ObjectHistogramVisitor object_visitor(isolate_);
   isolate_->heap()->IterateObjects(&object_visitor);
 }
 
 
 ObjectHistogram::ObjectHistogram(Isolate* isolate) {
   isolate_ = isolate;
   major_gc_count_ = 0;
   table_length_ = 512;
   table_ = reinterpret_cast<Element*>(
-    calloc(table_length_, sizeof(Element)));  // NOLINT 
+    calloc(table_length_, sizeof(Element)));  // NOLINT
   for (int index = 0; index < table_length_; index++) {
     table_[index].class_id_ = index;
   }
 }
 
 
 ObjectHistogram::~ObjectHistogram() {
   free(table_);
 }
 
@@ skipping 22 matching lines @@
   ASSERT(class_id < table_length_);
   table_[class_id].Add(obj->Size());
 }
 
 
 int ObjectHistogram::compare(const Element** a, const Element** b) {
   return (*b)->size_ - (*a)->size_;
 }
 
 
-void ObjectHistogram::Print() {
-  OS::Print("Printing Object Histogram\n");
-  OS::Print("____bytes___count_description____________\n");
-  // First count the number of non empty entries.
+ObjectHistogram::Element** ObjectHistogram::GetSortedArray(int* array_length) {
   int length = 0;
   for (int index = 0; index < table_length_; index++) {
     if (table_[index].count_ > 0) length++;
   }
   // Then add them to a new array and sort.
   Element** array = reinterpret_cast<Element**>(
     calloc(length, sizeof(Element*)));  // NOLINT
   int pos = 0;
   for (int index = 0; index < table_length_; index++) {
     if (table_[index].count_ > 0) array[pos++] = &table_[index];
   }
   typedef int (*CmpFunc)(const void*, const void*);
   qsort(array, length, sizeof(Element*),  // NOLINT
         reinterpret_cast<CmpFunc>(compare));
 
+  *array_length = length;
+  return array;
+}
+
+void ObjectHistogram::Print() {
+  OS::Print("Printing Object Histogram\n");
+  OS::Print("____bytes___count_description____________\n");
+  // First count the number of non empty entries.
+
+  int length = 0;
+  Element** array = NULL;
+
+  array = GetSortedArray(&length);
+  ASSERT(array != NULL);
+
   // Finally print the sorted array.
   Class& cls = Class::Handle();
   String& str = String::Handle();
   Library& lib = Library::Handle();
-  for (pos = 0; pos < length; pos++) {
+  for (int pos = 0; pos < length; pos++) {

[siva, 2013/08/01 18:16:18]

Ditto question about 'int' here.

[Cutch, 2013/08/01 22:22:04]

Legacy code used int. I'll change it to intptr_t.

     Element* e = array[pos];
     if (e->count_ > 0) {
       cls = isolate_->class_table()->At(e->class_id_);
       str = cls.Name();
       lib = cls.library();
       OS::Print("%9"Pd" %7"Pd" ",
                 e->size_ / major_gc_count_,
                 e->count_ / major_gc_count_);
       if (e->class_id_ < kInstanceCid) {
         OS::Print("`%s`", str.ToCString());  // VM names.
       } else {
         OS::Print("%s", str.ToCString());
       }
       if (lib.IsNull()) {
         OS::Print("\n");
       } else {
         str = lib.url();
         OS::Print(", library \'%s\'\n", str.ToCString());
       }
     }
   }
   // Deallocate the array for sorting.
   free(array);
 }
 
+void ObjectHistogram::PrintToJSONStream(JSONStream* stream) {
+  int length = 0;
+  Element** array = NULL;
+
+  array = GetSortedArray(&length);
+  ASSERT(array != NULL);
+
+  // Finally print the sorted array.
+  Class& cls = Class::Handle();
+  String& str = String::Handle();
+  Library& lib = Library::Handle();
+
+  intptr_t size_sum = 0;
+  intptr_t count_sum = 0;
+  stream->OpenObject();
+  stream->PrintProperty("type", "ObjectHistogram");
+  stream->OpenArray("properties");
+  stream->PrintValue("size");
+  stream->PrintValue("count");
+  stream->CloseArray();
+  stream->OpenArray("members");
+  for (int pos = 0; pos < length; pos++) {
+    Element* e = array[pos];
+    if (e->count_ > 0) {
+      cls = isolate_->class_table()->At(e->class_id_);
+      str = cls.Name();
+      lib = cls.library();
+      stream->OpenObject();
+      stream->PrintProperty("type", "ObjectHistogramEntry");
+      size_sum += e->size_ / major_gc_count_;
+      count_sum += e->count_ / major_gc_count_;

[siva, 2013/08/01 18:16:18]

(e->size_ / major_gc_count_) and (e->count_ / major_gc_count_) for
better readability.

The security review folks are going to ask about overflow here.

[Cutch, 2013/08/01 22:22:04]

Done.

+      stream->PrintProperty("size", e->size_ / major_gc_count_);
+      stream->PrintProperty("count", e->count_ / major_gc_count_);
+      stream->PrintProperty("name", str.ToCString());
+      if (lib.IsNull()) {
+        stream->PrintProperty("category", "");
+      } else {
+        str = lib.url();
+        stream->PrintProperty("category", str.ToCString());
+      }
+      stream->CloseObject();
+    }
+  }
+  stream->CloseArray();
+  stream->OpenObject("sums");
+  stream->PrintProperty("size", size_sum);
+  stream->PrintProperty("count", count_sum);
+  stream->CloseObject();
+  stream->CloseObject();
+
+  // Deallocate the array for sorting.
+  free(array);
+}
+
+
 }  // namespace dart