components/metrics: Add runtime memory leak detector

third_party/tcmalloc/chromium/src/leak_detector_impl.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 _LEAK_DETECTOR_IMPL_H_
+#define _LEAK_DETECTOR_IMPL_H_
+
+#include <unordered_set>
+
+#include "addressmap-inl.h"
+#include "base/basictypes.h"
+#include "base/custom_allocator.h"
+#include "heap-profile-stats.h"
+#include "leak_analyzer.h"
+
+namespace leak_detector {
+
+class CallStackTable;
+
+//----------------------------------------------------------------------
+// Class that contains the actual leak detection mechanism.
+//----------------------------------------------------------------------
+class LeakDetectorImpl {
+ public:
+  // Used for tracking allocation stats.
+  using Stats = HeapProfileStats;
+
+  LeakDetectorImpl(uint64 mapping_addr, uint64 mapping_size);
+  ~LeakDetectorImpl();
+
+  // Indicates whether the given allocation size has an associated call stack
+  // table, and thus requires a stack unwind.
+  bool ShouldGetStackTraceForSize(size_t size) const;
+
+  // Record allocs and frees.
+  void RecordAlloc(const void* ptr, size_t size,
+                   int stack_depth, const void* const call_stack[]);
+  void RecordFree(const void* ptr);
+
+  const Stats& stats() const {
+    return stats_;
+  }
+
+  // Run check for possible leaks based on the current profiling data.
+  void TestForLeaks();
+
+  // Dump current profiling statistics to log.
+  void DumpStats() const;
+
+ private:
+  // Used for tracking unique call stacks.
+  using CallStack = HeapProfileBucket;
+
+  // A record of allocations for a particular size.
+  struct AllocSizeEntry {
+    // Number of allocations and frees for this size.
+    uint32 num_allocs;
+    uint32 num_frees;
+
+    // A stack table, if this size is being profiled for stack as well.
+    CallStackTable* stack_table;
+  };
+
+  // Info stored in the address map
+  struct AllocInfo {
+    AllocInfo() : call_stack(NULL) {}
+
+    // Number of bytes in this allocation.
+    size_t bytes;
+
+    // Points to a unique call stack.
+    CallStack* call_stack;
+  };
+
+  // Used for recording size and call stack info for each allocation.
+  using AllocationMap = AddressMap<AllocInfo>;
+
+  // Hash table for tracking unique call stacks.
+  // TODO: Using std::unordered_set makes |CallStack::next| redundant. Consider
+  // creating a new struct or removing |next|.
+  using TableEntryAllocator = STL_Allocator<const CallStack*, CustomAllocator>;
+
+  struct CallStackCompare {
+    bool operator() (const CallStack* c1, const CallStack* c2) const {
+      return c1->depth == c2->depth &&
+             std::equal(c1->stack, c1->stack + c1->depth, c2->stack);
+    }
+  };
+
+  struct CallStackHash {
+    size_t operator() (const CallStack* call_stack) const {
+      return CallStackToHash(call_stack);
+    }
+  };
+
+  // Number of entries in the alloc size table. As sizes are aligned to 32-bits
+  // the max supported allocation size is (kNumSizeEntries * 4 - 1). Any larger
+  // sizes are ignored. This value is chosen high enough that such large sizes
+  // are rare if not nonexistent.
+  static const int kNumSizeEntries = 2048;
+
+  // Converts an allocation size to/from the array index used for |entries_|.
+  static int SizeToIndex(size_t size);
+  static size_t IndexToSize(int index);
+
+  // Accessor for the entry table.
+  inline AllocSizeEntry* GetEntryForSize(size_t size) {
+    return &entries_[SizeToIndex(size)];
+  }
+  inline const AllocSizeEntry& GetConstEntryForSize(size_t size) const {
+    return entries_[SizeToIndex(size)];
+  }
+
+  // Returns a CallStack object for a given call stack. Each unique call stack
+  // has its own CallStack object. If the given call stack has already been
+  // created by a previous call to this function, return a pointer to that same
+  // call stack object.
+  CallStack* GetCallStack(int depth, const void* const stack[]);
+
+  // Returns the offset of |ptr| within the current binary. If it is not in the
+  // current binary, just return |ptr| as an integer.
+  uint64 GetOffset(const void *ptr) const;
+
+  // Hash function for stack tables.
+  static size_t CallStackToHash(const CallStack* call_stack);
+
+  std::unordered_set<CallStack*,
+                     CallStackHash,
+                     CallStackCompare,
+                     TableEntryAllocator> call_stacks_;
+
+  // For tracking allocation stats.
+  Stats stats_;
+  Stats call_stack_stats_;
+  int num_stack_tables_;
+
+  // Stores all individual recorded allocations.
+  AllocationMap address_map_;
+
+  // Used to analyze potential leak patterns in the allocation sizes.
+  LeakAnalyzer<uint32> size_leak_analyzer_;
+
+  // Allocation stats for each size.
+  AllocSizeEntry entries_[kNumSizeEntries];
+
+  // Address mapping info of the current binary.
+  uint64 mapping_addr_;
+  uint64 mapping_size_;
+
+  DISALLOW_COPY_AND_ASSIGN(LeakDetectorImpl);
+};
+
+}  // namespace leak_detector
+
+#endif  // _LEAK_DETECTOR_IMPL_H_