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 "hdr/func/aligned_alloc.h" |
13 | #include "hdr/func/free.h" |
14 | #include "hdr/func/malloc.h" |
15 | #include "src/__support/common.h" |
16 | #include "src/__support/macros/config.h" |
17 | #include "src/__support/macros/properties/os.h" |
18 | |
19 | #include <stddef.h> // For size_t |
20 | |
21 | // Defining members in the std namespace is not preferred. But, we do it here |
22 | // so that we can use it to define the operator new which takes std::align_val_t |
23 | // argument. |
24 | namespace std { |
25 | |
26 | enum class align_val_t : size_t {}; |
27 | |
28 | } // namespace std |
29 | |
30 | namespace LIBC_NAMESPACE_DECL { |
31 | |
32 | class AllocChecker { |
33 | bool success = false; |
34 | |
35 | LIBC_INLINE AllocChecker &operator=(bool status) { |
36 | success = status; |
37 | return *this; |
38 | } |
39 | |
40 | public: |
41 | LIBC_INLINE AllocChecker() = default; |
42 | |
43 | LIBC_INLINE operator bool() const { return success; } |
44 | |
45 | LIBC_INLINE static void *alloc(size_t s, AllocChecker &ac) { |
46 | void *mem = ::malloc(s); |
47 | ac = (mem != nullptr); |
48 | return mem; |
49 | } |
50 | |
51 | LIBC_INLINE static void *aligned_alloc(size_t s, std::align_val_t align, |
52 | AllocChecker &ac) { |
53 | #ifdef LIBC_TARGET_OS_IS_WINDOWS |
54 | // std::aligned_alloc is not available on Windows because std::free on |
55 | // Windows cannot deallocate any over-aligned memory. Microsoft provides an |
56 | // alternative for std::aligned_alloc named _aligned_malloc, but it must be |
57 | // paired with _aligned_free instead of std::free. |
58 | void *mem = ::_aligned_malloc(static_cast<size_t>(align), s); |
59 | #else |
60 | void *mem = ::aligned_alloc(static_cast<size_t>(align), s); |
61 | #endif |
62 | ac = (mem != nullptr); |
63 | return mem; |
64 | } |
65 | }; |
66 | |
67 | } // namespace LIBC_NAMESPACE_DECL |
68 | |
69 | LIBC_INLINE void *operator new(size_t size, |
70 | LIBC_NAMESPACE::AllocChecker &ac) noexcept { |
71 | return LIBC_NAMESPACE::AllocChecker::alloc(size, ac); |
72 | } |
73 | |
74 | LIBC_INLINE void *operator new(size_t size, std::align_val_t align, |
75 | LIBC_NAMESPACE::AllocChecker &ac) noexcept { |
76 | return LIBC_NAMESPACE::AllocChecker::aligned_alloc(size, align, ac); |
77 | } |
78 | |
79 | LIBC_INLINE void *operator new[](size_t size, |
80 | LIBC_NAMESPACE::AllocChecker &ac) noexcept { |
81 | return LIBC_NAMESPACE::AllocChecker::alloc(size, ac); |
82 | } |
83 | |
84 | LIBC_INLINE void *operator new[](size_t size, std::align_val_t align, |
85 | LIBC_NAMESPACE::AllocChecker &ac) noexcept { |
86 | return LIBC_NAMESPACE::AllocChecker::aligned_alloc(size, align, ac); |
87 | } |
88 | |
89 | LIBC_INLINE void *operator new(size_t, void *p) { return p; } |
90 | |
91 | LIBC_INLINE void *operator new[](size_t, void *p) { return p; } |
92 | |
93 | // The ideal situation would be to define the various flavors of operator delete |
94 | // inlinelike we do with operator new above. However, since we need operator |
95 | // delete prototypes to match those specified by the C++ standard, we cannot |
96 | // define them inline as the C++ standard does not allow inline definitions of |
97 | // replacement operator delete implementations. Note also that we assign a |
98 | // special linkage name to each of these replacement operator delete functions. |
99 | // This is because, if we do not give them a special libc internal linkage name, |
100 | // they will replace operator delete for the entire application. Including this |
101 | // header file in all libc source files where operator delete is called ensures |
102 | // that only libc call sites use these replacement operator delete functions. |
103 | |
104 | #define DELETE_NAME(name) \ |
105 | __asm__(LIBC_MACRO_TO_STRING(LIBC_NAMESPACE) "_" LIBC_MACRO_TO_STRING(name)) |
106 | |
107 | void operator delete(void *) noexcept DELETE_NAME(delete); |
108 | void operator delete(void *, std::align_val_t) noexcept |
109 | DELETE_NAME(delete_aligned); |
110 | void operator delete(void *, size_t) noexcept DELETE_NAME(delete_sized); |
111 | void operator delete(void *, size_t, std::align_val_t) noexcept |
112 | DELETE_NAME(delete_sized_aligned); |
113 | void operator delete[](void *) noexcept DELETE_NAME(delete_array); |
114 | void operator delete[](void *, std::align_val_t) noexcept |
115 | DELETE_NAME(delete_array_aligned); |
116 | void operator delete[](void *, size_t) noexcept DELETE_NAME(delete_array_sized); |
117 | void operator delete[](void *, size_t, std::align_val_t) noexcept |
118 | DELETE_NAME(delete_array_sized_aligned); |
119 | |
120 | #undef DELETE_NAME |
121 | |
122 | #endif // LLVM_LIBC_SRC___SUPPORT_CPP_NEW_H |
123 | |