1.1 --- /dev/null Thu Jan 01 00:00:00 1970 +0000
1.2 +++ b/memory/build/replace_malloc.h Wed Dec 31 06:09:35 2014 +0100
1.3 @@ -0,0 +1,140 @@
1.4 +/* This Source Code Form is subject to the terms of the Mozilla Public
1.5 + * License, v. 2.0. If a copy of the MPL was not distributed with this file,
1.6 + * You can obtain one at http://mozilla.org/MPL/2.0/. */
1.7 +
1.8 +#ifndef replace_malloc_h
1.9 +#define replace_malloc_h
1.10 +
1.11 +/*
1.12 + * The replace_malloc facility allows an external library to replace or
1.13 + * supplement the jemalloc implementation.
1.14 + *
1.15 + * The external library may be hooked by setting one of the following
1.16 + * environment variables to the library path:
1.17 + * - LD_PRELOAD on Linux,
1.18 + * - DYLD_INSERT_LIBRARIES on OSX,
1.19 + * - MOZ_REPLACE_MALLOC_LIB on Windows and Android.
1.20 + *
1.21 + * An initialization function is called before any malloc replacement
1.22 + * function, and has the following declaration:
1.23 + *
1.24 + * void replace_init(const malloc_table_t *)
1.25 + *
1.26 + * The const malloc_table_t pointer given to that function is a table
1.27 + * containing pointers to the original jemalloc implementation, so that
1.28 + * replacement functions can call them back if they need to. The pointer
1.29 + * itself can safely be kept around (no need to copy the table itself).
1.30 + *
1.31 + * The functions to be implemented in the external library are of the form:
1.32 + *
1.33 + * void *replace_malloc(size_t size)
1.34 + * {
1.35 + * // Fiddle with the size if necessary.
1.36 + * // orig->malloc doesn't have to be called if the external library
1.37 + * // provides its own allocator, but in this case it will have to
1.38 + * // implement all functions.
1.39 + * void *ptr = orig->malloc(size);
1.40 + * // Do whatever you want with the ptr.
1.41 + * return ptr;
1.42 + * }
1.43 + *
1.44 + * where "orig" is the pointer obtained from replace_init.
1.45 + *
1.46 + * See malloc_decls.h for a list of functions that can be replaced this
1.47 + * way. The implementations are all in the form:
1.48 + * return_type replace_name(arguments [,...])
1.49 + *
1.50 + * They don't all need to be provided.
1.51 + *
1.52 + * Building a replace-malloc library is like rocket science. It can end up
1.53 + * with things blowing up, especially when trying to use complex types, and
1.54 + * even more especially when these types come from XPCOM or other parts of the
1.55 + * Mozilla codebase.
1.56 + * It is recommended to add the following to a replace-malloc implementation's
1.57 + * Makefile.in:
1.58 + * MOZ_GLUE_LDFLAGS = # Don't link against mozglue
1.59 + * WRAP_LDFLAGS = # Never wrap malloc function calls with -Wl,--wrap
1.60 + * and the following to the implementation's moz.build:
1.61 + * DISABLE_STL_WRAPPING = True # Avoid STL wrapping
1.62 + *
1.63 + * If your replace-malloc implementation lives under memory/replace, these
1.64 + * are taken care of by memory/replace/defs.mk.
1.65 + */
1.66 +
1.67 +/* Implementing a replace-malloc library is incompatible with using mozalloc. */
1.68 +#define MOZ_NO_MOZALLOC 1
1.69 +
1.70 +#include "mozilla/Types.h"
1.71 +
1.72 +MOZ_BEGIN_EXTERN_C
1.73 +
1.74 +#define MALLOC_DECL(name, return_type, ...) \
1.75 + typedef return_type(name ## _impl_t)(__VA_ARGS__);
1.76 +
1.77 +#include "malloc_decls.h"
1.78 +
1.79 +#define MALLOC_DECL(name, return_type, ...) \
1.80 + name ## _impl_t * name;
1.81 +
1.82 +typedef struct {
1.83 +#include "malloc_decls.h"
1.84 +} malloc_table_t;
1.85 +
1.86 +
1.87 +/* MOZ_NO_REPLACE_FUNC_DECL and MOZ_REPLACE_WEAK are only defined in
1.88 + * replace_malloc.c. Normally including this header will add function
1.89 + * definitions. */
1.90 +#ifndef MOZ_NO_REPLACE_FUNC_DECL
1.91 +
1.92 +# ifndef MOZ_REPLACE_WEAK
1.93 +# define MOZ_REPLACE_WEAK
1.94 +# endif
1.95 +
1.96 +# define MALLOC_DECL(name, return_type, ...) \
1.97 + MOZ_EXPORT return_type replace_ ## name(__VA_ARGS__) MOZ_REPLACE_WEAK;
1.98 +
1.99 +# define MALLOC_FUNCS MALLOC_FUNCS_ALL
1.100 +# include "malloc_decls.h"
1.101 +
1.102 +#endif /* MOZ_NO_REPLACE_FUNC_DECL */
1.103 +
1.104 +/*
1.105 + * posix_memalign, aligned_alloc, memalign and valloc all implement some
1.106 + * kind of aligned memory allocation. For convenience, replace_posix_memalign,
1.107 + * replace_aligned_alloc and replace_valloc can be automatically derived from
1.108 + * memalign when MOZ_REPLACE_ONLY_MEMALIGN is defined before including this
1.109 + * header. PAGE_SIZE also needs to be defined to the appropriate expression.
1.110 + */
1.111 +#ifdef MOZ_REPLACE_ONLY_MEMALIGN
1.112 +#include <errno.h>
1.113 +
1.114 +int replace_posix_memalign(void **ptr, size_t alignment, size_t size)
1.115 +{
1.116 + if (size == 0) {
1.117 + *ptr = NULL;
1.118 + return 0;
1.119 + }
1.120 + /* alignment must be a power of two and a multiple of sizeof(void *) */
1.121 + if (((alignment - 1) & alignment) != 0 || (alignment % sizeof(void *)))
1.122 + return EINVAL;
1.123 + *ptr = replace_memalign(alignment, size);
1.124 + return *ptr ? 0 : ENOMEM;
1.125 +}
1.126 +
1.127 +void *replace_aligned_alloc(size_t alignment, size_t size)
1.128 +{
1.129 + /* size should be a multiple of alignment */
1.130 + if (size % alignment)
1.131 + return NULL;
1.132 + return replace_memalign(alignment, size);
1.133 +}
1.134 +
1.135 +void *replace_valloc(size_t size)
1.136 +{
1.137 + return replace_memalign(PAGE_SIZE, size);
1.138 +}
1.139 +#endif
1.140 +
1.141 +MOZ_END_EXTERN_C
1.142 +
1.143 +#endif /* replace_malloc_h */
