1//===-- Libc specific custom operator new and delete ------------*- 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 LLVM_LIBC_SRC___SUPPORT_CPP_NEW_H
10#define LLVM_LIBC_SRC___SUPPORT_CPP_NEW_H
11
12#include "src/__support/common.h"
13
14#include <stddef.h> // For size_t
15#include <stdlib.h> // For malloc, free etc.
16
17// Defining members in the std namespace is not preferred. But, we do it here
18// so that we can use it to define the operator new which takes std::align_val_t
19// argument.
20namespace std {
21
22enum class align_val_t : size_t {};
23
24} // namespace std
25
26namespace LIBC_NAMESPACE {
27
28class AllocChecker {
29 bool success = false;
30
31 LIBC_INLINE AllocChecker &operator=(bool status) {
32 success = status;
33 return *this;
34 }
35
36public:
37 LIBC_INLINE AllocChecker() = default;
38
39 LIBC_INLINE operator bool() const { return success; }
40
41 LIBC_INLINE static void *alloc(size_t s, AllocChecker &ac) {
42 void *mem = ::malloc(size: s);
43 ac = (mem != nullptr);
44 return mem;
45 }
46
47 LIBC_INLINE static void *aligned_alloc(size_t s, std::align_val_t align,
48 AllocChecker &ac) {
49 void *mem = ::aligned_alloc(alignment: static_cast<size_t>(align), size: s);
50 ac = (mem != nullptr);
51 return mem;
52 }
53};
54
55} // namespace LIBC_NAMESPACE
56
57LIBC_INLINE void *operator new(size_t size,
58 LIBC_NAMESPACE::AllocChecker &ac) noexcept {
59 return LIBC_NAMESPACE::AllocChecker::alloc(s: size, ac);
60}
61
62LIBC_INLINE void *operator new(size_t size, std::align_val_t align,
63 LIBC_NAMESPACE::AllocChecker &ac) noexcept {
64 return LIBC_NAMESPACE::AllocChecker::aligned_alloc(s: size, align, ac);
65}
66
67LIBC_INLINE void *operator new[](size_t size,
68 LIBC_NAMESPACE::AllocChecker &ac) noexcept {
69 return LIBC_NAMESPACE::AllocChecker::alloc(s: size, ac);
70}
71
72LIBC_INLINE void *operator new[](size_t size, std::align_val_t align,
73 LIBC_NAMESPACE::AllocChecker &ac) noexcept {
74 return LIBC_NAMESPACE::AllocChecker::aligned_alloc(s: size, align, ac);
75}
76
77// The ideal situation would be to define the various flavors of operator delete
78// inlinelike we do with operator new above. However, since we need operator
79// delete prototypes to match those specified by the C++ standard, we cannot
80// define them inline as the C++ standard does not allow inline definitions of
81// replacement operator delete implementations. Note also that we assign a
82// special linkage name to each of these replacement operator delete functions.
83// This is because, if we do not give them a special libc internal linkage name,
84// they will replace operator delete for the entire application. Including this
85// header file in all libc source files where operator delete is called ensures
86// that only libc call sites use these replacement operator delete functions.
87
88#define DELETE_NAME(name) \
89 __asm__(LIBC_MACRO_TO_STRING(LIBC_NAMESPACE) "_" LIBC_MACRO_TO_STRING(name))
90
91void operator delete(void *) noexcept DELETE_NAME(delete);
92void operator delete(void *, std::align_val_t) noexcept
93 DELETE_NAME(delete_aligned);
94void operator delete(void *, size_t) noexcept DELETE_NAME(delete_sized);
95void operator delete(void *, size_t, std::align_val_t) noexcept
96 DELETE_NAME(delete_sized_aligned);
97void operator delete[](void *) noexcept DELETE_NAME(delete_array);
98void operator delete[](void *, std::align_val_t) noexcept
99 DELETE_NAME(delete_array_aligned);
100void operator delete[](void *, size_t) noexcept DELETE_NAME(delete_array_sized);
101void operator delete[](void *, size_t, std::align_val_t) noexcept
102 DELETE_NAME(delete_array_sized_aligned);
103
104#undef DELETE_NAME
105
106#endif // LLVM_LIBC_SRC___SUPPORT_CPP_NEW_H
107

source code of libc/src/__support/CPP/new.h