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4ae1509807
Replace-malloc libraries, such as DMD, don't really need to care about the details of implementing all the variants of aligned memory allocation functions. Currently, by defining MOZ_REPLACE_ONLY_MEMALIGN before including replace_malloc.h, they get predefined functions. Instead of making that an opt-in at build time, we make the replace-malloc initialization just fill the replace-malloc malloc_table_t with implementations that rely on the replace_memalign the library provides. --HG-- extra : rebase_source : 0842a67d9bc27a9a86c33d14d98b9c25f39982fb
97 lines
3.2 KiB
C
97 lines
3.2 KiB
C
/* This Source Code Form is subject to the terms of the Mozilla Public
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* License, v. 2.0. If a copy of the MPL was not distributed with this file,
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* You can obtain one at http://mozilla.org/MPL/2.0/. */
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#ifndef replace_malloc_h
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#define replace_malloc_h
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/*
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* The replace_malloc facility allows an external library to replace or
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* supplement the jemalloc implementation.
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*
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* The external library may be hooked by setting one of the following
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* environment variables to the library path:
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* - LD_PRELOAD on Linux,
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* - DYLD_INSERT_LIBRARIES on OSX,
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* - MOZ_REPLACE_MALLOC_LIB on Windows and Android.
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*
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* An initialization function is called before any malloc replacement
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* function, and has the following declaration:
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*
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* void replace_init(const malloc_table_t *)
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*
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* The const malloc_table_t pointer given to that function is a table
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* containing pointers to the original jemalloc implementation, so that
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* replacement functions can call them back if they need to. The pointer
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* itself can safely be kept around (no need to copy the table itself).
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*
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* The functions to be implemented in the external library are of the form:
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*
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* void *replace_malloc(size_t size)
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* {
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* // Fiddle with the size if necessary.
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* // orig->malloc doesn't have to be called if the external library
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* // provides its own allocator, but in this case it will have to
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* // implement all functions.
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* void *ptr = orig->malloc(size);
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* // Do whatever you want with the ptr.
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* return ptr;
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* }
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*
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* where "orig" is the pointer obtained from replace_init.
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*
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* See malloc_decls.h for a list of functions that can be replaced this
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* way. The implementations are all in the form:
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* return_type replace_name(arguments [,...])
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*
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* They don't all need to be provided.
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*
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* Building a replace-malloc library is like rocket science. It can end up
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* with things blowing up, especially when trying to use complex types, and
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* even more especially when these types come from XPCOM or other parts of the
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* Mozilla codebase.
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* It is recommended to add the following to a replace-malloc implementation's
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* moz.build:
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* DISABLE_STL_WRAPPING = True # Avoid STL wrapping
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*
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* If your replace-malloc implementation lives under memory/replace, these
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* are taken care of by memory/replace/defs.mk.
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*/
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#ifdef replace_malloc_bridge_h
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#error Do not include replace_malloc_bridge.h before replace_malloc.h. \
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In fact, you only need the latter.
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#endif
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#define REPLACE_MALLOC_IMPL
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#include "replace_malloc_bridge.h"
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/* Implementing a replace-malloc library is incompatible with using mozalloc. */
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#define MOZ_NO_MOZALLOC 1
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#include "mozilla/Types.h"
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MOZ_BEGIN_EXTERN_C
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/* MOZ_NO_REPLACE_FUNC_DECL and MOZ_REPLACE_WEAK are only defined in
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* replace_malloc.c. Normally including this header will add function
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* definitions. */
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#ifndef MOZ_NO_REPLACE_FUNC_DECL
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# ifndef MOZ_REPLACE_WEAK
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# define MOZ_REPLACE_WEAK
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# endif
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# define MALLOC_DECL(name, return_type, ...) \
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MOZ_EXPORT return_type replace_ ## name(__VA_ARGS__) MOZ_REPLACE_WEAK;
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# define MALLOC_FUNCS MALLOC_FUNCS_ALL
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# include "malloc_decls.h"
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#endif /* MOZ_NO_REPLACE_FUNC_DECL */
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MOZ_END_EXTERN_C
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#endif /* replace_malloc_h */
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