// 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 #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::operator()(const StackFrame& frame) const { return hash()(frame.value); } size_t hash::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::operator()(const AllocationContext& ctx) const { size_t backtrace_hash = hash()(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(ctx.type_name) * 2654435761; // Multiply one side to break the commutativity of +. Multiplication with a // number coprime to |numeric_limits::max() + 1| is bijective so // randomness is preserved. return (backtrace_hash * 3) + type_hash; } } // namespace std