1 // Copyright 2024 The Pigweed Authors 2 // 3 // Licensed under the Apache License, Version 2.0 (the "License"); you may not 4 // use this file except in compliance with the License. You may obtain a copy of 5 // the License at 6 // 7 // https://www.apache.org/licenses/LICENSE-2.0 8 // 9 // Unless required by applicable law or agreed to in writing, software 10 // distributed under the License is distributed on an "AS IS" BASIS, WITHOUT 11 // WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the 12 // License for the specific language governing permissions and limitations under 13 // the License. 14 #pragma once 15 16 #include "pw_allocator/config.h" 17 #include "pw_assert/assert.h" 18 #include "pw_preprocessor/compiler.h" 19 20 namespace pw::allocator { 21 22 /// Configuration that determines which validation checks will performed. 23 /// 24 /// This purely-static type provides both symbols that can be used to 25 /// conditionally exclude unwanted checks, as well as common arithmetic routines 26 /// that can perform overflow checking when configured to do so. 27 /// 28 /// The behavior of this type is determined by the `PW_ALLOCATOR_HARDENING` 29 /// module configuration option. 30 struct Hardening { 31 enum Checks { 32 kBasic = PW_ALLOCATOR_HARDENING_BASIC, 33 kRobust = PW_ALLOCATOR_HARDENING_ROBUST, 34 kDebug = PW_ALLOCATOR_HARDENING_DEBUG, 35 }; 36 37 static constexpr bool kIncludesBasicChecks = 38 PW_ALLOCATOR_HARDENING >= PW_ALLOCATOR_HARDENING_BASIC; 39 40 static constexpr bool kIncludesRobustChecks = 41 PW_ALLOCATOR_HARDENING >= PW_ALLOCATOR_HARDENING_ROBUST; 42 43 static constexpr bool kIncludesDebugChecks = 44 PW_ALLOCATOR_HARDENING >= PW_ALLOCATOR_HARDENING_DEBUG; 45 46 template <typename T, typename U> IncrementHardening47 static constexpr void Increment(T& value, U increment) { 48 if constexpr (Hardening::kIncludesRobustChecks) { 49 PW_ASSERT(!PW_ADD_OVERFLOW(value, increment, &value)); 50 } else { 51 value += increment; 52 } 53 } 54 55 template <typename T, typename U> DecrementHardening56 static constexpr void Decrement(T& value, U increment) { 57 if constexpr (Hardening::kIncludesRobustChecks) { 58 PW_ASSERT(!PW_SUB_OVERFLOW(value, increment, &value)); 59 } else { 60 value -= increment; 61 } 62 } 63 64 template <typename T, typename U> MultiplyHardening65 static constexpr void Multiply(T& value, U increment) { 66 if constexpr (Hardening::kIncludesRobustChecks) { 67 PW_ASSERT(!PW_MUL_OVERFLOW(value, increment, &value)); 68 } else { 69 value *= increment; 70 } 71 } 72 }; 73 74 } // namespace pw::allocator 75