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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 "base/trace_event/heap_profiler_allocation_context.h"
- #include <cstring>
- #include "base/hash/hash.h"
- namespace base {
- namespace trace_event {
- bool operator < (const StackFrame& lhs, const StackFrame& rhs) {
- return lhs.value < rhs.value;
- }
- bool operator == (const StackFrame& lhs, const StackFrame& rhs) {
- return lhs.value == rhs.value;
- }
- bool operator != (const StackFrame& lhs, const StackFrame& rhs) {
- return !(lhs.value == rhs.value);
- }
- Backtrace::Backtrace() = default;
- bool operator==(const Backtrace& lhs, const Backtrace& rhs) {
- if (lhs.frame_count != rhs.frame_count) return false;
- return std::equal(lhs.frames, lhs.frames + lhs.frame_count, rhs.frames);
- }
- bool operator!=(const Backtrace& lhs, const Backtrace& rhs) {
- return !(lhs == rhs);
- }
- AllocationContext::AllocationContext(): type_name(nullptr) {}
- AllocationContext::AllocationContext(const Backtrace& backtrace,
- const char* type_name)
- : backtrace(backtrace), type_name(type_name) {}
- bool operator==(const AllocationContext& lhs, const AllocationContext& rhs) {
- return (lhs.backtrace == rhs.backtrace) && (lhs.type_name == rhs.type_name);
- }
- bool operator!=(const AllocationContext& lhs, const AllocationContext& rhs) {
- return !(lhs == rhs);
- }
- } // namespace trace_event
- } // namespace base
- namespace std {
- using base::trace_event::AllocationContext;
- using base::trace_event::Backtrace;
- using base::trace_event::StackFrame;
- size_t hash<StackFrame>::operator()(const StackFrame& frame) const {
- return hash<const void*>()(frame.value);
- }
- size_t hash<Backtrace>::operator()(const Backtrace& backtrace) const {
- const void* values[Backtrace::kMaxFrameCount];
- for (size_t i = 0; i != backtrace.frame_count; ++i) {
- values[i] = backtrace.frames[i].value;
- }
- return base::PersistentHash(values, backtrace.frame_count * sizeof(*values));
- }
- size_t hash<AllocationContext>::operator()(const AllocationContext& ctx) const {
- size_t backtrace_hash = hash<Backtrace>()(ctx.backtrace);
- // Multiplicative hash from [Knuth 1998]. Works best if |size_t| is 32 bits,
- // because the magic number is a prime very close to 2^32 / golden ratio, but
- // will still redistribute keys bijectively on 64-bit architectures because
- // the magic number is coprime to 2^64.
- size_t type_hash = reinterpret_cast<size_t>(ctx.type_name) * 2654435761;
- // Multiply one side to break the commutativity of +. Multiplication with a
- // number coprime to |numeric_limits<size_t>::max() + 1| is bijective so
- // randomness is preserved.
- return (backtrace_hash * 3) + type_hash;
- }
- } // namespace std
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