1 //===- MemAlloc.h - Memory allocation functions -----------------*- 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 /// \file
9 ///
10 /// This file defines counterparts of C library allocation functions defined in
11 /// the namespace 'std'. The new allocation functions crash on allocation
12 /// failure instead of returning null pointer.
13 ///
14 //===----------------------------------------------------------------------===//
15 
16 #ifndef LLVM_SUPPORT_MEMALLOC_H
17 #define LLVM_SUPPORT_MEMALLOC_H
18 
19 #include "llvm/Support/Compiler.h"
20 #include "llvm/Support/ErrorHandling.h"
21 #include <cstdlib>
22 
23 namespace llvm {
24 
25 LLVM_ATTRIBUTE_RETURNS_NONNULL inline void *safe_malloc(size_t Sz) {
26   void *Result = std::malloc(Sz);
27   if (Result == nullptr) {
28     // It is implementation-defined whether allocation occurs if the space
29     // requested is zero (ISO/IEC 9899:2018 7.22.3). Retry, requesting
30     // non-zero, if the space requested was zero.
31     if (Sz == 0)
32       return safe_malloc(1);
33     report_bad_alloc_error("Allocation failed");
34   }
35   return Result;
36 }
37 
38 LLVM_ATTRIBUTE_RETURNS_NONNULL inline void *safe_calloc(size_t Count,
39                                                         size_t Sz) {
40   void *Result = std::calloc(Count, Sz);
41   if (Result == nullptr) {
42     // It is implementation-defined whether allocation occurs if the space
43     // requested is zero (ISO/IEC 9899:2018 7.22.3). Retry, requesting
44     // non-zero, if the space requested was zero.
45     if (Count == 0 || Sz == 0)
46       return safe_malloc(1);
47     report_bad_alloc_error("Allocation failed");
48   }
49   return Result;
50 }
51 
52 LLVM_ATTRIBUTE_RETURNS_NONNULL inline void *safe_realloc(void *Ptr, size_t Sz) {
53   void *Result = std::realloc(Ptr, Sz);
54   if (Result == nullptr) {
55     // It is implementation-defined whether allocation occurs if the space
56     // requested is zero (ISO/IEC 9899:2018 7.22.3). Retry, requesting
57     // non-zero, if the space requested was zero.
58     if (Sz == 0)
59       return safe_malloc(1);
60     report_bad_alloc_error("Allocation failed");
61   }
62   return Result;
63 }
64 
65 /// Allocate a buffer of memory with the given size and alignment.
66 ///
67 /// When the compiler supports aligned operator new, this will use it to to
68 /// handle even over-aligned allocations.
69 ///
70 /// However, this doesn't make any attempt to leverage the fancier techniques
71 /// like posix_memalign due to portability. It is mostly intended to allow
72 /// compatibility with platforms that, after aligned allocation was added, use
73 /// reduced default alignment.
74 LLVM_ATTRIBUTE_RETURNS_NONNULL LLVM_ATTRIBUTE_RETURNS_NOALIAS void *
75 allocate_buffer(size_t Size, size_t Alignment);
76 
77 /// Deallocate a buffer of memory with the given size and alignment.
78 ///
79 /// If supported, this will used the sized delete operator. Also if supported,
80 /// this will pass the alignment to the delete operator.
81 ///
82 /// The pointer must have been allocated with the corresponding new operator,
83 /// most likely using the above helper.
84 void deallocate_buffer(void *Ptr, size_t Size, size_t Alignment);
85 
86 } // namespace llvm
87 #endif
88