Track live instance and allocation counts for classes

runtime/vm/assembler_ia32.cc

Index: runtime/vm/assembler_ia32.cc
diff --git a/runtime/vm/assembler_ia32.cc b/runtime/vm/assembler_ia32.cc
index 6a7af21729e638e7aedf9f3532f7644fba8078b6..772d79852c3087abdb80bde84e9bcf17ea80ee68 100644
--- a/runtime/vm/assembler_ia32.cc
+++ b/runtime/vm/assembler_ia32.cc
@@ -8,6 +8,7 @@
 #include "vm/assembler.h"
 #include "vm/code_generator.h"
 #include "vm/heap.h"
+#include "vm/heap_class_stats.h"
 #include "vm/memory_region.h"
 #include "vm/runtime_entry.h"
 #include "vm/stack_frame.h"
@@ -2252,11 +2253,30 @@ void Assembler::Bind(Label* label) {
 }
 
 
+// Updates the allocation count for cid.
+void Assembler::BumpAllocationCount(intptr_t cid,
+                                    Register temp_reg) {
+  ASSERT(temp_reg != kNoRegister);
+  HeapClassStatistics* heap_class_stats =
+      Isolate::Current()->heap_class_stats();
+  // temp_reg gets address of class table pointer.
+  movl(temp_reg, Address::Absolute(heap_class_stats->ClassStatsTableAddress()));
+  // Offset into class table.
+  const intptr_t offset = cid * sizeof(HeapClassData);  // NOLINT
+  // temp_reg points at HeapClassData for cid + offset to allocation count.
+  leal(temp_reg, Address(temp_reg, offset));
+  // Increment allocation count.
+  addl(Address(temp_reg, HeapClassData::allocated_since_gc_offset()),
+       Immediate(1));
+}
+
 void Assembler::TryAllocate(const Class& cls,
                             Label* failure,
                             bool near_jump,
-                            Register instance_reg) {
+                            Register instance_reg,
+                            Register temp_reg) {
   ASSERT(failure != NULL);
+  ASSERT(temp_reg != kNoRegister);
   if (FLAG_inline_alloc) {
     Heap* heap = Isolate::Current()->heap();
     const intptr_t instance_size = cls.instance_size();
@@ -2268,6 +2288,7 @@ void Assembler::TryAllocate(const Class& cls,
     // Successfully allocated the object, now update top to point to
     // next object start and store the class in the class field of object.
     movl(Address::Absolute(heap->TopAddress()), instance_reg);
+    BumpAllocationCount(cls.id(), temp_reg);
     ASSERT(instance_size >= kHeapObjectTag);
     subl(instance_reg, Immediate(instance_size - kHeapObjectTag));
     uword tags = 0;