llvm/compiler-rt/lib/scudo/standalone/secondary.h

//===-- secondary.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
//
//===----------------------------------------------------------------------===//

#ifndef SCUDO_SECONDARY_H_
#define SCUDO_SECONDARY_H_

#include "chunk.h"
#include "common.h"
#include "list.h"
#include "mem_map.h"
#include "memtag.h"
#include "mutex.h"
#include "options.h"
#include "stats.h"
#include "string_utils.h"
#include "thread_annotations.h"
#include "vector.h"

namespace scudo {

// This allocator wraps the platform allocation primitives, and as such is on
// the slower side and should preferably be used for larger sized allocations.
// Blocks allocated will be preceded and followed by a guard page, and hold
// their own header that is not checksummed: the guard pages and the Combined
// header should be enough for our purpose.

namespace LargeBlock {

struct alignas(Max<uptr>(archSupportsMemoryTagging()
                             ? archMemoryTagGranuleSize()
                             : 1,
                         1U << SCUDO_MIN_ALIGNMENT_LOG)) Header { … };

static_assert …;
static_assert …;

constexpr uptr getHeaderSize() { … }

template <typename Config> static uptr addHeaderTag(uptr Ptr) { … }

template <typename Config> static Header *getHeader(uptr Ptr) { … }

template <typename Config> static Header *getHeader(const void *Ptr) { … }

} // namespace LargeBlock

static inline void unmap(MemMapT &MemMap) { … }

namespace {

struct CachedBlock { … };
} // namespace

template <typename Config> class MapAllocatorNoCache { … };

static const uptr MaxUnreleasedCachePages = …;

template <typename Config>
bool mapSecondary(const Options &Options, uptr CommitBase, uptr CommitSize,
                  uptr AllocPos, uptr Flags, MemMapT &MemMap) { … }

// Template specialization to avoid producing zero-length array
template <typename T, size_t Size> class NonZeroLengthArray { … };
NonZeroLengthArray<T, 0>;

// The default unmap callback is simply scudo::unmap.
// In testing, a different unmap callback is used to
// record information about unmaps in the cache
template <typename Config, void (*unmapCallBack)(MemMapT &) = unmap>
class MapAllocatorCache { … };

template <typename Config> class MapAllocator { … };

template <typename Config>
void *
MapAllocator<Config>::tryAllocateFromCache(const Options &Options, uptr Size,
                                           uptr Alignment, uptr *BlockEndPtr,
                                           FillContentsMode FillContents) { … }
// As with the Primary, the size passed to this function includes any desired
// alignment, so that the frontend can align the user allocation. The hint
// parameter allows us to unmap spurious memory when dealing with larger
// (greater than a page) alignments on 32-bit platforms.
// Due to the sparsity of address space available on those platforms, requesting
// an allocation from the Secondary with a large alignment would end up wasting
// VA space (even though we are not committing the whole thing), hence the need
// to trim off some of the reserved space.
// For allocations requested with an alignment greater than or equal to a page,
// the committed memory will amount to something close to Size - AlignmentHint
// (pending rounding and headers).
template <typename Config>
void *MapAllocator<Config>::allocate(const Options &Options, uptr Size,
                                     uptr Alignment, uptr *BlockEndPtr,
                                     FillContentsMode FillContents) { … }

template <typename Config>
void MapAllocator<Config>::deallocate(const Options &Options, void *Ptr)
    EXCLUDES(Mutex) { … }

template <typename Config>
void MapAllocator<Config>::getStats(ScopedString *Str) EXCLUDES(Mutex) { … }

} // namespace scudo

#endif // SCUDO_SECONDARY_H_