components/metrics: Add runtime memory leak detector

third_party/tcmalloc/chromium/src/call_stack_table.h

+// Copyright (c) 2015 The Chromium Authors. All rights reserved.
+// Use of this source code is governed by a BSD-style license that can be
+// found in the LICENSE file.
+
+// ---
+// Author: Simon Que
+
+#ifndef _CALL_STACK_TABLE_H_
+#define _CALL_STACK_TABLE_H_
+
+#include <unordered_map>
+#include <functional>
+
+#include "base/basictypes.h"
+#include "base/stl_allocator.h"
+#include "heap-profile-stats.h"
+#include "leak_analyzer.h"
+
+namespace leak_detector {
+
+// Contains a hash table where the key is the call stack bucket and the value is
+// the number of allocations from that call stack.
+class CallStackTable {
+ public:
+  // Local allocation function pointer types.
+  typedef void* (*Allocator)(size_t size);
+  typedef void  (*DeAllocator)(void* ptr);
+
+  // Bucket that represents a unique call stack.
+  using Bucket = HeapProfileBucket;
+
+  class Alloc {
+   public:
+    static void Init(Allocator alloc, DeAllocator dealloc);
+    static void* Allocate(size_t size);
+    static void Free(void* ptr, size_t size);
+
+   private:
+    static Allocator alloc_;
+    static DeAllocator dealloc_;
+  };
+
+  struct Hash {
+    long operator() (const Bucket* bucket) const {
+      return bucket->hash;
+    }
+  };
+
+  CallStackTable(Allocator alloc, DeAllocator dealloc);
+  ~CallStackTable();
+
+  // Add/Remove an allocation for the given call stack bucket.
+  void Add(const Bucket* ptr);
+  void Remove(const Bucket* ptr);
+
+  // Dump contents to log buffer |buffer| of size |size|.
+  int Dump(char* buffer, int size) const;
+
+  // Check for leak patterns in the allocation data.
+  void TestForLeaks();
+
+  const LeakAnalyzer<const Bucket*>& leak_analyzer() const {
+    return leak_analyzer_;
+  }
+
+ private:
+  // Hash table entry used to track number of allocs and frees for a call stack.
+  // We don't want to reuse the HeapProfileBucket struct for this because it
+  // requires too much space by storing a full call stack. Instead, this custom
+  // struct contains a pointer to an existing HeapProfileBucket (alias Bucket).
+  struct Entry {
+    // Number of allocs/frees for the call stack.
+    uint32 num_allocs;
+    uint32 num_frees;
+  };
+
+  // The total number of recorded allocations when this object was created. This
+  // acts as a timestamp of sorts.
+  uint64_t total_num_allocs_at_creation_;
+
+  // Total number of allocs and frees in this table.
+  uint32 num_allocs_;
+  uint32 num_frees_;
+
+  // For local allocation.
+  Allocator alloc_;
+  DeAllocator dealloc_;
+  using TableEntryAllocator =
+      STL_Allocator<std::pair<const Bucket*, Entry>, Alloc>;
+  std::unordered_map<const Bucket*,
+                     Entry,
+                     Hash,
+                     std::equal_to<const Bucket*>,
+                     TableEntryAllocator> entry_map_;
+
+  // For detecting leak patterns in incoming allocations.
+  LeakAnalyzer<const Bucket*> leak_analyzer_;
+
+  DISALLOW_COPY_AND_ASSIGN(CallStackTable);
+};
+
+}  // namespace leak_detector
+
+#endif  // _CALL_STACK_TABLE_H_