1/*
2 * Copyright 2010-2011 PathScale, Inc. All rights reserved.
3 *
4 * Redistribution and use in source and binary forms, with or without
5 * modification, are permitted provided that the following conditions are met:
6 *
7 * 1. Redistributions of source code must retain the above copyright notice,
8 *    this list of conditions and the following disclaimer.
9 *
10 * 2. Redistributions in binary form must reproduce the above copyright notice,
11 *    this list of conditions and the following disclaimer in the documentation
12 *    and/or other materials provided with the distribution.
13 *
14 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS ``AS
15 * IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
16 * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR
17 * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDER OR
18 * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL,
19 * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO,
20 * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS;
21 * OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
22 * WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
23 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
24 * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
25 */
26
27/**
28 * memory.cc - Contains stub definition of C++ new/delete operators.
29 *
30 * These definitions are intended to be used for testing and are weak symbols
31 * to allow them to be replaced by definitions from a STL implementation.
32 * These versions simply wrap malloc() and free(), they do not provide a
33 * C++-specific allocator.
34 */
35
36#include <stddef.h>
37#include <stdlib.h>
38#include "stdexcept.h"
39#include "atomic.h"
40
41
42namespace std
43{
44	struct nothrow_t {};
45}
46
47
48/// The type of the function called when allocation fails.
49typedef void (*new_handler)();
50/**
51 * The function to call when allocation fails.  By default, there is no
52 * handler and a bad allocation exception is thrown if an allocation fails.
53 */
54static atomic<new_handler> new_handl{nullptr};
55
56namespace std
57{
58	/**
59	 * Sets a function to be called when there is a failure in new.
60	 */
61	__attribute__((weak))
62	new_handler set_new_handler(new_handler handler)
63	{
64		return new_handl.exchange(handler);
65	}
66
67	__attribute__((weak))
68	new_handler get_new_handler(void)
69	{
70		return new_handl.load();
71	}
72}
73
74
75#if __cplusplus < 201103L
76#define NOEXCEPT throw()
77#define BADALLOC throw(std::bad_alloc)
78#else
79#define NOEXCEPT noexcept
80#define BADALLOC
81#endif
82
83namespace
84{
85	/**
86	 * Helper for forwarding from no-throw operators to versions that can
87	 * return nullptr.  Catches any exception and converts it into a nullptr
88	 * return.
89	 */
90	template<void*(New)(size_t)>
91	void *noexcept_new(size_t size)
92	{
93#if !defined(_CXXRT_NO_EXCEPTIONS)
94	try
95	{
96		return New(size);
97	} catch (...)
98	{
99		// nothrow operator new should return NULL in case of
100		// std::bad_alloc exception in new handler
101		return nullptr;
102	}
103#else
104	return New(size);
105#endif
106	}
107}
108
109
110__attribute__((weak))
111void* operator new(size_t size) BADALLOC
112{
113	if (0 == size)
114	{
115		size = 1;
116	}
117	void * mem = malloc(size);
118	while (0 == mem)
119	{
120		new_handler h = std::get_new_handler();
121		if (0 != h)
122		{
123			h();
124		}
125		else
126		{
127#if !defined(_CXXRT_NO_EXCEPTIONS)
128			throw std::bad_alloc();
129#else
130			break;
131#endif
132		}
133		mem = malloc(size);
134	}
135
136	return mem;
137}
138
139
140__attribute__((weak))
141void* operator new(size_t size, const std::nothrow_t &) NOEXCEPT
142{
143	return noexcept_new<(::operator new)>(size);
144}
145
146
147__attribute__((weak))
148void operator delete(void * ptr) NOEXCEPT
149{
150	free(ptr);
151}
152
153
154__attribute__((weak))
155void * operator new[](size_t size) BADALLOC
156{
157	return ::operator new(size);
158}
159
160
161__attribute__((weak))
162void * operator new[](size_t size, const std::nothrow_t &) NOEXCEPT
163{
164	return noexcept_new<(::operator new[])>(size);
165}
166
167
168__attribute__((weak))
169void operator delete[](void * ptr) NOEXCEPT
170{
171	::operator delete(ptr);
172}
173
174// C++14 additional delete operators
175
176#if __cplusplus >= 201402L
177
178__attribute__((weak))
179void operator delete(void * ptr, size_t) NOEXCEPT
180{
181	::operator delete(ptr);
182}
183
184
185__attribute__((weak))
186void operator delete[](void * ptr, size_t) NOEXCEPT
187{
188	::operator delete(ptr);
189}
190
191#endif
192