compiler-rt/lib/scudo/standalone/options.h

   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
  16 namespace scudo {
  17
  18 enum class OptionBit {
  19   MayReturnNull,
  20   FillContents0of2,
  21   FillContents1of2,
  22   DeallocTypeMismatch,
  23   DeleteSizeMismatch,
  24   TrackAllocationStacks,
  25   UseOddEvenTags,
  26   UseMemoryTagging,
  27   AddLargeAllocationSlack,
  28 };
  29
  30 struct 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
  41 template <typename Config> bool useMemoryTagging(const Options &Options) {
  42   return allocatorSupportsMemoryTagging<Config>() &&
  43          Options.get(OptionBit::UseMemoryTagging);
  44 }
  45
  46 struct 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_