gecko-dev/memory/mozalloc/mozalloc.h

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7.2 KiB
C++

/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*-
* vim: sw=2 ts=4 et :
*/
/* This Source Code Form is subject to the terms of the Mozilla Public
* License, v. 2.0. If a copy of the MPL was not distributed with this
* file, You can obtain one at http://mozilla.org/MPL/2.0/. */
#ifndef mozilla_mozalloc_h
#define mozilla_mozalloc_h
/*
* https://bugzilla.mozilla.org/show_bug.cgi?id=427099
*/
#if defined(__cplusplus)
# include <new>
// Since libstdc++ 6, including the C headers (e.g. stdlib.h) instead of the
// corresponding C++ header (e.g. cstdlib) can cause confusion in C++ code
// using things defined there. Specifically, with stdlib.h, the use of abs()
// in gfx/graphite2/src/inc/UtfCodec.h somehow ends up picking the wrong abs()
# include <cstdlib>
#else
# include <stdlib.h>
#endif
#if defined(__cplusplus)
# include "mozilla/fallible.h"
# include "mozilla/mozalloc_abort.h"
# include "mozilla/TemplateLib.h"
#endif
#include "mozilla/Attributes.h"
#include "mozilla/Types.h"
MOZ_BEGIN_EXTERN_C
/*
* We need to use malloc_impl and free_impl in this file when they are
* defined, because of how mozglue.dll is linked on Windows, where using
* malloc/free would end up using the symbols from the MSVCRT instead of
* ours.
*/
#ifndef free_impl
# define free_impl free
# define free_impl_
#endif
#ifndef malloc_impl
# define malloc_impl malloc
# define malloc_impl_
#endif
/*
* Each declaration below is analogous to a "standard" allocation
* function, except that the out-of-memory handling is made explicit.
* The |moz_x| versions will never return a NULL pointer; if memory
* is exhausted, they abort. The |moz_| versions may return NULL
* pointers if memory is exhausted: their return value must be checked.
*
* All these allocation functions are *guaranteed* to return a pointer
* to memory allocated in such a way that that memory can be freed by
* passing that pointer to |free()|.
*/
MFBT_API void* moz_xmalloc(size_t size) MOZ_ALLOCATOR;
MFBT_API void* moz_xcalloc(size_t nmemb, size_t size) MOZ_ALLOCATOR;
MFBT_API void* moz_xrealloc(void* ptr, size_t size) MOZ_ALLOCATOR;
MFBT_API char* moz_xstrdup(const char* str) MOZ_ALLOCATOR;
#if defined(HAVE_STRNDUP)
MFBT_API char* moz_xstrndup(const char* str, size_t strsize) MOZ_ALLOCATOR;
#endif /* if defined(HAVE_STRNDUP) */
MFBT_API void* moz_xmemdup(const void* ptr, size_t size) MOZ_ALLOCATOR;
MFBT_API void* moz_xmemalign(size_t boundary, size_t size) MOZ_ALLOCATOR;
MFBT_API size_t moz_malloc_usable_size(void* ptr);
MFBT_API size_t moz_malloc_size_of(const void* ptr);
/*
* Like moz_malloc_size_of(), but works reliably with interior pointers, i.e.
* pointers into the middle of a live allocation.
*/
MFBT_API size_t moz_malloc_enclosing_size_of(const void* ptr);
MOZ_END_EXTERN_C
#ifdef __cplusplus
/*
* We implement the default operators new/delete as part of
* libmozalloc, replacing their definitions in libstdc++. The
* operator new* definitions in libmozalloc will never return a NULL
* pointer.
*
* Each operator new immediately below returns a pointer to memory
* that can be delete'd by any of
*
* (1) the matching infallible operator delete immediately below
* (2) the matching system |operator delete(void*, std::nothrow)|
* (3) the matching system |operator delete(void*) noexcept(false)|
*
* NB: these are declared |noexcept(false)|, though they will never
* throw that exception. This declaration is consistent with the rule
* that |::operator new() noexcept(false)| will never return NULL.
*
* NB: mozilla::fallible can be used instead of std::nothrow.
*/
/* NB: This is defined just to silence vacuous warnings about symbol
* visibility on OS X/gcc. These symbols are force-inline and not
* exported. */
# if defined(XP_MACOSX)
# define MOZALLOC_EXPORT_NEW MFBT_API
# else
# define MOZALLOC_EXPORT_NEW
# endif
MOZALLOC_EXPORT_NEW
# if defined(__GNUC__) && !defined(__clang__) && defined(__SANITIZE_ADDRESS__)
/* gcc's asan somehow doesn't like always_inline on this function. */
__attribute__((gnu_inline)) inline
# else
MOZ_ALWAYS_INLINE_EVEN_DEBUG
# endif
void*
operator new(size_t size) noexcept(false) {
return moz_xmalloc(size);
}
MOZALLOC_EXPORT_NEW MOZ_ALWAYS_INLINE_EVEN_DEBUG void* operator new(
size_t size, const std::nothrow_t&) noexcept(true) {
return malloc_impl(size);
}
MOZALLOC_EXPORT_NEW MOZ_ALWAYS_INLINE_EVEN_DEBUG void* operator new[](
size_t size) noexcept(false) {
return moz_xmalloc(size);
}
MOZALLOC_EXPORT_NEW MOZ_ALWAYS_INLINE_EVEN_DEBUG void* operator new[](
size_t size, const std::nothrow_t&) noexcept(true) {
return malloc_impl(size);
}
MOZALLOC_EXPORT_NEW MOZ_ALWAYS_INLINE_EVEN_DEBUG void operator delete(
void* ptr) noexcept(true) {
return free_impl(ptr);
}
MOZALLOC_EXPORT_NEW MOZ_ALWAYS_INLINE_EVEN_DEBUG void operator delete(
void* ptr, const std::nothrow_t&)noexcept(true) {
return free_impl(ptr);
}
MOZALLOC_EXPORT_NEW MOZ_ALWAYS_INLINE_EVEN_DEBUG void operator delete[](
void* ptr) noexcept(true) {
return free_impl(ptr);
}
MOZALLOC_EXPORT_NEW MOZ_ALWAYS_INLINE_EVEN_DEBUG void operator delete[](
void* ptr, const std::nothrow_t&) noexcept(true) {
return free_impl(ptr);
}
# if defined(XP_WIN)
// We provide the global sized delete overloads unconditionally because the
// MSVC runtime headers do, despite compiling with /Zc:sizedDealloc-
MOZALLOC_EXPORT_NEW MOZ_ALWAYS_INLINE_EVEN_DEBUG void operator delete(
void* ptr, size_t /*size*/) noexcept(true) {
return free_impl(ptr);
}
MOZALLOC_EXPORT_NEW MOZ_ALWAYS_INLINE_EVEN_DEBUG void operator delete[](
void* ptr, size_t /*size*/) noexcept(true) {
return free_impl(ptr);
}
# endif
/*
* This policy is identical to MallocAllocPolicy, except it uses
* moz_xmalloc/moz_xcalloc/moz_xrealloc instead of
* malloc/calloc/realloc.
*/
class InfallibleAllocPolicy {
public:
template <typename T>
T* maybe_pod_malloc(size_t aNumElems) {
return pod_malloc<T>(aNumElems);
}
template <typename T>
T* maybe_pod_calloc(size_t aNumElems) {
return pod_calloc<T>(aNumElems);
}
template <typename T>
T* maybe_pod_realloc(T* aPtr, size_t aOldSize, size_t aNewSize) {
return pod_realloc<T>(aPtr, aOldSize, aNewSize);
}
template <typename T>
T* pod_malloc(size_t aNumElems) {
if (aNumElems & mozilla::tl::MulOverflowMask<sizeof(T)>::value) {
reportAllocOverflow();
}
return static_cast<T*>(moz_xmalloc(aNumElems * sizeof(T)));
}
template <typename T>
T* pod_calloc(size_t aNumElems) {
return static_cast<T*>(moz_xcalloc(aNumElems, sizeof(T)));
}
template <typename T>
T* pod_realloc(T* aPtr, size_t aOldSize, size_t aNewSize) {
if (aNewSize & mozilla::tl::MulOverflowMask<sizeof(T)>::value) {
reportAllocOverflow();
}
return static_cast<T*>(moz_xrealloc(aPtr, aNewSize * sizeof(T)));
}
template <typename T>
void free_(T* aPtr, size_t aNumElems = 0) {
free_impl(aPtr);
}
void reportAllocOverflow() const { mozalloc_abort("alloc overflow"); }
bool checkSimulatedOOM() const { return true; }
};
#endif /* ifdef __cplusplus */
#ifdef malloc_impl_
# undef malloc_impl_
# undef malloc_impl
#endif
#ifdef free_impl_
# undef free_impl_
# undef free_impl
#endif
#endif /* ifndef mozilla_mozalloc_h */