components/metrics: Add runtime memory leak detector

components/metrics/leak_detector/leak_detector_impl.h

+// Copyright 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.
+
+#ifndef COMPONENTS_METRICS_LEAK_DETECTOR_LEAK_DETECTOR_IMPL_H_
+#define COMPONENTS_METRICS_LEAK_DETECTOR_LEAK_DETECTOR_IMPL_H_
+
+#include <stdint.h>
+
+#include <unordered_set>
+
+#include "components/metrics/leak_detector/call_stack_table.h"
+#include "components/metrics/leak_detector/leak_analyzer.h"
+#include <gperftools/custom_allocator.h>
+
+namespace leak_detector {
+
+//----------------------------------------------------------------------
+// Class that contains the actual leak detection mechanism.
+//----------------------------------------------------------------------
+class LeakDetectorImpl {
+ public:
+  LeakDetectorImpl(uint64_t mapping_addr,
+                   uint64_t mapping_size,
+                   int size_suspicion_threshold,
+                   int call_stack_suspicion_threshold,
+                   bool verbose);
+  ~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);
+
+  // Run check for possible leaks based on the current profiling data.
+  void TestForLeaks();
+
+  // Dump current profiling statistics to log.
+  void DumpStats() const;
+
+ private:
+  // A record of allocations for a particular size.
+  struct AllocSizeEntry {
+    // Number of allocations and frees for this size.
+    uint32_t num_allocs;
+    uint32_t num_frees;
+
+    // A stack table, if this size is being profiled for stack as well.
+    CallStackTable* stack_table;
+  };
+
+  // Info for a single allocation.
+  struct AllocInfo {
+    AllocInfo() : call_stack(nullptr) {}
+
+    // Number of bytes in this allocation.
+    size_t bytes;
+
+    // Points to a unique call stack.
+    const CallStack* call_stack;
+  };
+
+  // Allocator class for allocation entry map. Maps allocated addresses to
+  // AllocInfo objects.
+  using AllocationEntryAllocator =
+      STL_Allocator<std::pair<const void*, AllocInfo>, CustomAllocator>;
+
+  // Allocator class for unique call stacks.
+  using TableEntryAllocator = STL_Allocator<const CallStack*, CustomAllocator>;
+
+  // Hash class for addresses.
+  struct AddressHash {
+    size_t operator() (const void* ptr) const;
+  };
+
+  // Comparator class for call stack objects.
+  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);
+    }
+  };
+
+  // Hash class for call stack objects.
+  struct CallStackHash {
+    size_t operator() (const CallStack* call_stack) const;
+  };
+
+  // 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_t GetOffset(const void *ptr) const;
+
+  // Hash function for stack tables.
+  static size_t CallStackToHash(const CallStack* call_stack);
+
+  // Owns all unique call stack objects, which are allocated on the heap. Any
+  // other class or function that references a call stack must get it from here,
+  // but may not take ownership of the call stack object.
+  std::unordered_set<CallStack*,
+                     CallStackHash,
+                     CallStackCompare,
+                     TableEntryAllocator> call_stacks_;
+
+  // Allocation stats.
+  uint64_t num_allocs_;
+  uint64_t num_frees_;
+  uint64_t alloc_size_;
+  uint64_t free_size_;
+
+  uint32_t num_allocs_with_call_stack_;
+  uint32_t num_stack_tables_;
+
+  // Stores all individual recorded allocations.
+  std::unordered_map<const void*,
+                     AllocInfo,
+                     AddressHash,
+                     std::equal_to<const void*>,
+                     AllocationEntryAllocator> address_map_;
+
+  // Used to analyze potential leak patterns in the allocation sizes.
+  LeakAnalyzer size_leak_analyzer_;
+
+  // Allocation stats for each size.
+  AllocSizeEntry entries_[kNumSizeEntries];
+
+  // Address mapping info of the current binary.
+  uint64_t mapping_addr_;
+  uint64_t mapping_size_;
+
+  // Number of consecutive times an allocation size must trigger suspicion to be
+  // considered a leak suspect.
+  int size_suspicion_threshold_;
+
+  // Number of consecutive times a call stack must trigger suspicion to be
+  // considered a leak suspect.
+  int call_stack_suspicion_threshold_;
+
+  // Enable verbose dumping of much more leak analysis data.
+  bool verbose_;
+
+  DISALLOW_COPY_AND_ASSIGN(LeakDetectorImpl);
+};
+
+}  // namespace leak_detector
+
+#endif  // COMPONENTS_METRICS_LEAK_DETECTOR_LEAK_DETECTOR_IMPL_H_