Make heap size estimation more accurate.

test/cctest/test-heap.cc

 // Copyright 2011 the V8 project authors. All rights reserved.
 
 #include <stdlib.h>
 
 #include "v8.h"
 
 #include "execution.h"
 #include "factory.h"
 #include "macro-assembler.h"
 #include "global-handles.h"
@@ skipping 1169 matching lines @@
   CHECK_EQ(opt ? 4 : 0, CountOptimizedUserFunctions(ctx[0]));
   CHECK_EQ(opt ? 4 : 0, CountOptimizedUserFunctionsWithGC(ctx[0], 2));
   CompileRun("f5()");
   CHECK_EQ(opt ? 5 : 0, CountOptimizedUserFunctions(ctx[0]));
   CHECK_EQ(opt ? 5 : 0, CountOptimizedUserFunctionsWithGC(ctx[0], 4));
 
   ctx[0]->Exit();
 }
 
 
+TEST(TestSizeOfObjects) {
+  v8::V8::Initialize();
+
+  // Get initial heap size after several full GCs, which will stabilize
+  // the heap size and return with sweeping finished completely.
+  HEAP->CollectAllGarbage(Heap::kNoGCFlags);
+  HEAP->CollectAllGarbage(Heap::kNoGCFlags);
+  HEAP->CollectAllGarbage(Heap::kNoGCFlags);
+  HEAP->CollectAllGarbage(Heap::kNoGCFlags);
+  CHECK(HEAP->old_pointer_space()->IsSweepingComplete());
+  intptr_t initial_size = HEAP->SizeOfObjects();
+
+  {
+    // Allocate objects on several different old-space pages so that
+    // lazy sweeping kicks in for subsequent GC runs.
+    AlwaysAllocateScope always_allocate;
+    intptr_t filler_size = FixedArray::SizeFor(8192);
+    for (int i = 1; i <= 100; i++) {
+      HEAP->AllocateFixedArray(8192, TENURED)->ToObjectChecked();
+      CHECK_EQ(initial_size + i * filler_size, HEAP->SizeOfObjects());
+    }
+  }
+
+  // The heap size should go back to initial size after a full GC, even
+  // though sweeping didn't finish yet.
+  HEAP->CollectAllGarbage(Heap::kNoGCFlags);
+  CHECK(!HEAP->old_pointer_space()->IsSweepingComplete());
+  CHECK_EQ(initial_size, HEAP->SizeOfObjects());
+
+  // Advancing the sweeper step-wise should not change the heap size.
+  while (!HEAP->old_pointer_space()->IsSweepingComplete()) {
+    HEAP->old_pointer_space()->AdvanceSweeper(KB);
+    CHECK_EQ(initial_size, HEAP->SizeOfObjects());
+  }
+}
+
+
 TEST(TestSizeOfObjectsVsHeapIteratorPrecision) {
   InitializeVM();
   HEAP->EnsureHeapIsIterable();
   intptr_t size_of_objects_1 = HEAP->SizeOfObjects();
   HeapIterator iterator;
   intptr_t size_of_objects_2 = 0;
   for (HeapObject* obj = iterator.next();
        obj != NULL;
        obj = iterator.next()) {
     size_of_objects_2 += obj->Size();
@@ skipping 269 matching lines @@
     ctx2->Exit();
     ctx1->Exit();
     ctx1.Dispose();
   }
   HEAP->CollectAllAvailableGarbage();
   CHECK_EQ(2, NumberOfGlobalObjects());
   ctx2.Dispose();
   HEAP->CollectAllAvailableGarbage();
   CHECK_EQ(0, NumberOfGlobalObjects());
 }