xray_allocator.h | Explore in Territory

//===-- xray_allocator.h ---------------------------------------*- C++ -*-===//
//
// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
// See https://llvm.org/LICENSE.txt for license information.
// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
//
//===----------------------------------------------------------------------===//
//
// This file is a part of XRay, a dynamic runtime instrumentation system.
//
// Defines the allocator interface for an arena allocator, used primarily for
// the profiling runtime.
//
//===----------------------------------------------------------------------===//
#ifndef XRAY_ALLOCATOR_H
#define XRAY_ALLOCATOR_H

#include "sanitizer_common/sanitizer_common.h"
#include "sanitizer_common/sanitizer_internal_defs.h"
#include "sanitizer_common/sanitizer_mutex.h"
#if SANITIZER_FUCHSIA
#include <zircon/process.h>
#include <zircon/status.h>
#include <zircon/syscalls.h>
#else
#include "sanitizer_common/sanitizer_posix.h"
#endif
#include "xray_defs.h"
#include "xray_utils.h"
#include <cstddef>
#include <cstdint>
#include <sys/mman.h>

namespace __xray {

// We implement our own memory allocation routine which will bypass the
// internal allocator. This allows us to manage the memory directly, using
// mmap'ed memory to back the allocators.
template <class T> T *allocate() XRAY_NEVER_INSTRUMENT { … }

template <class T> void deallocate(T *B) XRAY_NEVER_INSTRUMENT { … }

template <class T = unsigned char>
T *allocateBuffer(size_t S) XRAY_NEVER_INSTRUMENT { … }

template <class T> void deallocateBuffer(T *B, size_t S) XRAY_NEVER_INSTRUMENT { … }

template <class T, class... U>
T *initArray(size_t N, U &&... Us) XRAY_NEVER_INSTRUMENT { … }

/// The Allocator type hands out fixed-sized chunks of memory that are
/// cache-line aligned and sized. This is useful for placement of
/// performance-sensitive data in memory that's frequently accessed. The
/// allocator also self-limits the peak memory usage to a dynamically defined
/// maximum.
///
/// N is the lower-bound size of the block of memory to return from the
/// allocation function. N is used to compute the size of a block, which is
/// cache-line-size multiples worth of memory. We compute the size of a block by
/// determining how many cache lines worth of memory is required to subsume N.
///
/// The Allocator instance will manage its own memory acquired through mmap.
/// This severely constrains the platforms on which this can be used to POSIX
/// systems where mmap semantics are well-defined.
///
/// FIXME: Isolate the lower-level memory management to a different abstraction
/// that can be platform-specific.
template <size_t N> struct Allocator { … };

} // namespace __xray

#endif // XRAY_ALLOCATOR_H
llvm/compiler-rt/lib/xray/xray_allocator.h
