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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.
#include "leak_detector_impl.h"
#include <inttypes.h>
#include <stddef.h>
#include <algorithm>
#include <new>
#include "base/hash.h"
#include "base/process/process_handle.h"
#include "components/metrics/leak_detector/call_stack_table.h"
#include "components/metrics/leak_detector/custom_allocator.h"
#include "components/metrics/leak_detector/ranked_list.h"
namespace metrics {
namespace leak_detector {
namespace {
// Look for leaks in the the top N entries in each tier, where N is this value.
const int kRankedListSize = 16;
// Initial hash table size for |LeakDetectorImpl::address_map_|.
const int kAddressMapNumBuckets = 100003;
// 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.
const int kNumSizeEntries = 2048;
using ValueType = LeakDetectorValueType;
// Functions to convert an allocation size to/from the array index used for
// |LeakDetectorImpl::size_entries_|.
size_t SizeToIndex(const size_t size) {
int result = static_cast<int>(size / sizeof(uint32_t));
if (result < kNumSizeEntries)
return result;
return 0;
}
size_t IndexToSize(size_t index) {
return sizeof(uint32_t) * index;
}
} // namespace
LeakDetectorImpl::LeakReport::LeakReport() : alloc_size_bytes_(0) {}
LeakDetectorImpl::LeakReport::~LeakReport() {}
bool LeakDetectorImpl::LeakReport::operator<(const LeakReport& other) const {
if (alloc_size_bytes_ != other.alloc_size_bytes_)
return alloc_size_bytes_ < other.alloc_size_bytes_;
for (size_t i = 0; i < call_stack_.size() && i < other.call_stack_.size();
++i) {
if (call_stack_[i] != other.call_stack_[i])
return call_stack_[i] < other.call_stack_[i];
}
return call_stack_.size() < other.call_stack_.size();
}
LeakDetectorImpl::LeakDetectorImpl(uintptr_t mapping_addr,
size_t mapping_size,
int size_suspicion_threshold,
int call_stack_suspicion_threshold)
: num_allocs_(0),
num_frees_(0),
alloc_size_(0),
free_size_(0),
num_allocs_with_call_stack_(0),
num_stack_tables_(0),
address_map_(kAddressMapNumBuckets),
size_leak_analyzer_(kRankedListSize, size_suspicion_threshold),
size_entries_(kNumSizeEntries),
mapping_addr_(mapping_addr),
mapping_size_(mapping_size),
call_stack_suspicion_threshold_(call_stack_suspicion_threshold) {}
LeakDetectorImpl::~LeakDetectorImpl() {
// Free any call stack tables.
for (AllocSizeEntry& entry : size_entries_) {
CallStackTable* table = entry.stack_table;
if (!table)
continue;
table->~CallStackTable();
CustomAllocator::Free(table, sizeof(CallStackTable));
}
size_entries_.clear();
}
bool LeakDetectorImpl::ShouldGetStackTraceForSize(size_t size) const {
return size_entries_[SizeToIndex(size)].stack_table != nullptr;
}
void LeakDetectorImpl::RecordAlloc(const void* ptr,
size_t size,
int stack_depth,
const void* const stack[]) {
AllocInfo alloc_info;
alloc_info.size = size;
alloc_size_ += alloc_info.size;
++num_allocs_;
AllocSizeEntry* entry = &size_entries_[SizeToIndex(size)];
++entry->num_allocs;
if (entry->stack_table && stack_depth > 0) {
alloc_info.call_stack =
call_stack_manager_.GetCallStack(stack_depth, stack);
entry->stack_table->Add(alloc_info.call_stack);
++num_allocs_with_call_stack_;
}
uintptr_t addr = reinterpret_cast<uintptr_t>(ptr);
address_map_.insert(std::pair<uintptr_t, AllocInfo>(addr, alloc_info));
}
void LeakDetectorImpl::RecordFree(const void* ptr) {
// Look up address.
uintptr_t addr = reinterpret_cast<uintptr_t>(ptr);
auto iter = address_map_.find(addr);
// TODO(sque): Catch and report double frees.
if (iter == address_map_.end())
return;
const AllocInfo& alloc_info = iter->second;
AllocSizeEntry* entry = &size_entries_[SizeToIndex(alloc_info.size)];
++entry->num_frees;
const CallStack* call_stack = alloc_info.call_stack;
if (call_stack) {
if (entry->stack_table)
entry->stack_table->Remove(call_stack);
}
++num_frees_;
free_size_ += alloc_info.size;
address_map_.erase(iter);
}
void LeakDetectorImpl::TestForLeaks(InternalVector<LeakReport>* reports) {
// Add net alloc counts for each size to a ranked list.
RankedList size_ranked_list(kRankedListSize);
for (size_t i = 0; i < size_entries_.size(); ++i) {
const AllocSizeEntry& entry = size_entries_[i];
ValueType size_value(IndexToSize(i));
size_ranked_list.Add(size_value, entry.num_allocs - entry.num_frees);
}
size_leak_analyzer_.AddSample(std::move(size_ranked_list));
// Get suspected leaks by size.
for (const ValueType& size_value : size_leak_analyzer_.suspected_leaks()) {
uint32_t size = size_value.size();
AllocSizeEntry* entry = &size_entries_[SizeToIndex(size)];
if (entry->stack_table)
continue;
entry->stack_table = new (CustomAllocator::Allocate(sizeof(CallStackTable)))
CallStackTable(call_stack_suspicion_threshold_);
++num_stack_tables_;
}
// Check for leaks in each CallStackTable. It makes sense to this before
// checking the size allocations, because that could potentially create new
// CallStackTable. However, the overhead to check a new CallStackTable is
// small since this function is run very rarely. So handle the leak checks of
// Tier 2 here.
reports->clear();
for (size_t i = 0; i < size_entries_.size(); ++i) {
const AllocSizeEntry& entry = size_entries_[i];
CallStackTable* stack_table = entry.stack_table;
if (!stack_table || stack_table->empty())
continue;
size_t size = IndexToSize(i);
// Get suspected leaks by call stack.
stack_table->TestForLeaks();
const LeakAnalyzer& leak_analyzer = stack_table->leak_analyzer();
for (const ValueType& call_stack_value : leak_analyzer.suspected_leaks()) {
const CallStack* call_stack = call_stack_value.call_stack();
// Return reports by storing in |*reports|.
reports->resize(reports->size() + 1);
LeakReport* report = &reports->back();
report->alloc_size_bytes_ = size;
report->call_stack_.resize(call_stack->depth);
for (size_t j = 0; j < call_stack->depth; ++j) {
report->call_stack_[j] = GetOffset(call_stack->stack[j]);
}
}
}
}
size_t LeakDetectorImpl::AddressHash::operator()(uintptr_t addr) const {
return base::Hash(reinterpret_cast<const char*>(&addr), sizeof(addr));
}
uintptr_t LeakDetectorImpl::GetOffset(const void* ptr) const {
uintptr_t ptr_value = reinterpret_cast<uintptr_t>(ptr);
if (ptr_value >= mapping_addr_ && ptr_value < mapping_addr_ + mapping_size_)
return ptr_value - mapping_addr_;
return ptr_value;
}
} // namespace leak_detector
} // namespace metrics
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