1//===-- options.h -----------------------------------------------*- C++ -*-===//
2//
3// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4// See https://llvm.org/LICENSE.txt for license information.
5// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6//
7//===----------------------------------------------------------------------===//
8
9#ifndef SCUDO_OPTIONS_H_
10#define SCUDO_OPTIONS_H_
11
12#include "atomic_helpers.h"
13#include "common.h"
14#include "memtag.h"
15
16namespace scudo {
17
18enum class OptionBit {
19  MayReturnNull,
20  FillContents0of2,
21  FillContents1of2,
22  DeallocTypeMismatch,
23  DeleteSizeMismatch,
24  TrackAllocationStacks,
25  UseOddEvenTags,
26  UseMemoryTagging,
27  AddLargeAllocationSlack,
28};
29
30struct Options {
31  u32 Val;
32
33  bool get(OptionBit Opt) const { return Val & (1U << static_cast<u32>(Opt)); }
34
35  FillContentsMode getFillContentsMode() const {
36    return static_cast<FillContentsMode>(
37        (Val >> static_cast<u32>(OptionBit::FillContents0of2)) & 3);
38  }
39};
40
41template <typename Config> bool useMemoryTagging(Options Options) {
42  return allocatorSupportsMemoryTagging<Config>() &&
43         Options.get(OptionBit::UseMemoryTagging);
44}
45
46struct AtomicOptions {
47  atomic_u32 Val = {};
48
49  Options load() const { return Options{atomic_load_relaxed(&Val)}; }
50
51  void clear(OptionBit Opt) {
52    atomic_fetch_and(&Val, ~(1U << static_cast<u32>(Opt)),
53                     memory_order_relaxed);
54  }
55
56  void set(OptionBit Opt) {
57    atomic_fetch_or(&Val, 1U << static_cast<u32>(Opt), memory_order_relaxed);
58  }
59
60  void setFillContentsMode(FillContentsMode FillContents) {
61    u32 Opts = atomic_load_relaxed(&Val), NewOpts;
62    do {
63      NewOpts = Opts;
64      NewOpts &= ~(3U << static_cast<u32>(OptionBit::FillContents0of2));
65      NewOpts |= static_cast<u32>(FillContents)
66                 << static_cast<u32>(OptionBit::FillContents0of2);
67    } while (!atomic_compare_exchange_strong(&Val, &Opts, NewOpts,
68                                             memory_order_relaxed));
69  }
70};
71
72} // namespace scudo
73
74#endif // SCUDO_OPTIONS_H_
75