components/metrics: Add runtime memory leak detector

components/metrics/leak_detector/leak_detector_impl.h

Index: components/metrics/leak_detector/leak_detector_impl.h
diff --git a/components/metrics/leak_detector/leak_detector_impl.h b/components/metrics/leak_detector/leak_detector_impl.h
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+++ b/components/metrics/leak_detector/leak_detector_impl.h
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+// 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 <vector>
+
+#include "base/containers/hash_tables.h"
+#include "base/macros.h"
+#include "components/metrics/leak_detector/call_stack_manager.h"
+#include "components/metrics/leak_detector/custom_allocator.h"
+#include "components/metrics/leak_detector/leak_analyzer.h"
+
+namespace metrics {
+namespace leak_detector {
+
+class CallStackTable;
+
+// Class that contains the actual leak detection mechanism.
+// Not thread-safe.
+class LeakDetectorImpl {
+ public:
+  // Vector type that's safe to use within the memory leak detector. Uses
+  // CustomAllocator to avoid recursive malloc hook invocation.
+  template <typename T>
+  using InternalVector = std::vector<T, STLAllocator<T, CustomAllocator>>;
+
+  // Leak report generated by LeakDetectorImpl.
+  class LeakReport {
+   public:
+    LeakReport();
+    ~LeakReport();
+
+    size_t alloc_size_bytes() const { return alloc_size_bytes_; }
+
+    const InternalVector<uintptr_t>& call_stack() const { return call_stack_; }
+
+    // Used to compare the contents of two leak reports.
+    bool operator<(const LeakReport& other) const;
+
+   private:
+    // LeakDetectorImpl needs access to class members when creating a new leak
+    // report.
+    friend class LeakDetectorImpl;
+
+    // Number of bytes allocated by the leak site during each allocation.
+    size_t alloc_size_bytes_;
+
+    // Unlike the CallStack struct, which consists of addresses, this call stack
+    // will contain offsets in the executable binary.
+    InternalVector<uintptr_t> call_stack_;
+
+    // TODO(sque): Add leak detector parameters.
+  };
+
+  LeakDetectorImpl(uintptr_t mapping_addr,
+                   size_t mapping_size,
+                   int size_suspicion_threshold,
+                   int call_stack_suspicion_threshold);
+  ~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(InternalVector<LeakReport>* reports);
+
+ 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 size;
+
+    // Points to a unique call stack.
+    const CallStack* call_stack;
+  };
+
+  // Allocator class for allocation entry map. Maps allocated addresses to
+  // AllocInfo objects.
+  using AllocationEntryAllocator =
+      STLAllocator<std::pair<const void*, AllocInfo>, CustomAllocator>;
+
+  // Hash class for addresses.
+  struct AddressHash {
+    size_t operator()(uintptr_t addr) const;
+  };
+
+  // Returns the offset of |ptr| within the current binary. If it is not in the
+  // current binary, just return |ptr| as an integer.
+  uintptr_t GetOffset(const void* ptr) const;
+
+  // 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.
+  CallStackManager call_stack_manager_;
+
+  // 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.
+  base::hash_map<uintptr_t,
+                 AllocInfo,
+                 AddressHash,
+                 std::equal_to<uintptr_t>,
+                 AllocationEntryAllocator> address_map_;
+
+  // Used to analyze potential leak patterns in the allocation sizes.
+  LeakAnalyzer size_leak_analyzer_;
+
+  // Allocation stats for each size.
+  InternalVector<AllocSizeEntry> size_entries_;
+
+  // Address mapping info of the current binary.
+  uintptr_t mapping_addr_;
+  size_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_;
+
+  DISALLOW_COPY_AND_ASSIGN(LeakDetectorImpl);
+};
+
+}  // namespace leak_detector
+}  // namespace metrics
+
+#endif  // COMPONENTS_METRICS_LEAK_DETECTOR_LEAK_DETECTOR_IMPL_H_