Implemented basic heap memory allocation tracking in MallocHooks using hooks registered with tcmall…

runtime/vm/malloc_hooks.h

 // Copyright (c) 2017, 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.
 
 #ifndef RUNTIME_VM_MALLOC_HOOKS_H_
 #define RUNTIME_VM_MALLOC_HOOKS_H_
 
 #include "vm/globals.h"
 
+#if defined(DART_USE_TCMALLOC)
+// The following macros are also defined in tcmalloc.
+// We'll push them onto a stack and restore them after we're finished including
+// headers from tcmalloc.
+#pragma push_macro("COMPILE_ASSERT")
+#pragma push_macro("DISALLOW_COPY_AND_ASSIGN")
+#pragma push_macro("ASSERT")
+#undef COMPILE_ASSERT
+#undef DISALLOW_COPY_AND_ASSIGN
+#undef ASSERT
+
+#include "base/low_level_alloc.h"
+#include "./addressmap-inl.h"
+
+// Restore VM macro definitions.
+#pragma pop_macro("ASSERT")
+#pragma pop_macro("DISALLOW_COPY_AND_ASSIGN")
+#pragma pop_macro("COMPILE_ASSERT")
+#endif  // defined(DART_USE_TCMALLOC)
+
 namespace dart {
 
 class MallocHooks {
+ public:
   static void Init();
+  static void TearDown();
+
+#if defined(DART_USE_TCMALLOC)
+  static uintptr_t heap_allocated_memory_in_bytes() {
+    return heap_allocated_memory_in_bytes_;
+  }
+#else
+  static uintptr_t heap_allocated_memory_in_bytes() { return 0; }
+#endif
 
  private:
+#if defined(DART_USE_TCMALLOC)
+
+  static bool initialized_;
+
+  // Memory arena used by MallocHooks custom malloc and free calls
+  // to avoid dependencies on tcmalloc malloc and free.
+  static LowLevelAlloc::Arena* malloc_hooks_memory_;
+
+  // Custom malloc implementation.
+  static void* MallocHooksMalloc(size_t bytes) {
+    return LowLevelAlloc::AllocWithArena(bytes, malloc_hooks_memory_);
+  }
+
+  // Custom free implementation.
+  static void MallocHooksFree(void* p) { LowLevelAlloc::Free(p); }
+
+  // Hooks.
+  static void RecordAllocHook(const void* ptr, size_t size);
+  static void RecordFreeHook(const void* ptr);
+
+  static uintptr_t heap_allocated_memory_in_bytes_;
+  static AddressMap<uintptr_t>* allocation_map_;
+
+#endif  // defined(DART_USE_TCMALLOC)
+
   DISALLOW_ALLOCATION();
   DISALLOW_IMPLICIT_CONSTRUCTORS(MallocHooks);
 };
 
 }  // namespace dart
 
 #endif  // RUNTIME_VM_MALLOC_HOOKS_H_