| /* |
| This is a version (aka dlmalloc) of malloc/free/realloc written by |
| Doug Lea and released to the public domain, as explained at |
| http://creativecommons.org/publicdomain/zero/1.0/ Send questions, |
| comments, complaints, performance data, etc to dl@cs.oswego.edu |
| |
| * Version 2.8.6 Wed Aug 29 06:57:58 2012 Doug Lea |
| Note: There may be an updated version of this malloc obtainable at |
| ftp://gee.cs.oswego.edu/pub/misc/malloc.c |
| Check before installing! |
| |
| * Quickstart |
| |
| This library is all in one file to simplify the most common usage: |
| ftp it, compile it (-O3), and link it into another program. All of |
| the compile-time options default to reasonable values for use on |
| most platforms. You might later want to step through various |
| compile-time and dynamic tuning options. |
| |
| For convenience, an include file for code using this malloc is at: |
| ftp://gee.cs.oswego.edu/pub/misc/malloc-2.8.6.h |
| You don't really need this .h file unless you call functions not |
| defined in your system include files. The .h file contains only the |
| excerpts from this file needed for using this malloc on ANSI C/C++ |
| systems, so long as you haven't changed compile-time options about |
| naming and tuning parameters. If you do, then you can create your |
| own malloc.h that does include all settings by cutting at the point |
| indicated below. Note that you may already by default be using a C |
| library containing a malloc that is based on some version of this |
| malloc (for example in linux). You might still want to use the one |
| in this file to customize settings or to avoid overheads associated |
| with library versions. |
| |
| * Vital statistics: |
| |
| Supported pointer/size_t representation: 4 or 8 bytes |
| size_t MUST be an unsigned type of the same width as |
| pointers. (If you are using an ancient system that declares |
| size_t as a signed type, or need it to be a different width |
| than pointers, you can use a previous release of this malloc |
| (e.g. 2.7.2) supporting these.) |
| |
| Alignment: 8 bytes (minimum) |
| This suffices for nearly all current machines and C compilers. |
| However, you can define MALLOC_ALIGNMENT to be wider than this |
| if necessary (up to 128bytes), at the expense of using more space. |
| |
| Minimum overhead per allocated chunk: 4 or 8 bytes (if 4byte sizes) |
| 8 or 16 bytes (if 8byte sizes) |
| Each malloced chunk has a hidden word of overhead holding size |
| and status information, and additional cross-check word |
| if FOOTERS is defined. |
| |
| Minimum allocated size: 4-byte ptrs: 16 bytes (including overhead) |
| 8-byte ptrs: 32 bytes (including overhead) |
| |
| Even a request for zero bytes (i.e., malloc(0)) returns a |
| pointer to something of the minimum allocatable size. |
| The maximum overhead wastage (i.e., number of extra bytes |
| allocated than were requested in malloc) is less than or equal |
| to the minimum size, except for requests >= mmap_threshold that |
| are serviced via mmap(), where the worst case wastage is about |
| 32 bytes plus the remainder from a system page (the minimal |
| mmap unit); typically 4096 or 8192 bytes. |
| |
| Security: static-safe; optionally more or less |
| The "security" of malloc refers to the ability of malicious |
| code to accentuate the effects of errors (for example, freeing |
| space that is not currently malloc'ed or overwriting past the |
| ends of chunks) in code that calls malloc. This malloc |
| guarantees not to modify any memory locations below the base of |
| heap, i.e., static variables, even in the presence of usage |
| errors. The routines additionally detect most improper frees |
| and reallocs. All this holds as long as the static bookkeeping |
| for malloc itself is not corrupted by some other means. This |
| is only one aspect of security -- these checks do not, and |
| cannot, detect all possible programming errors. |
| |
| If FOOTERS is defined nonzero, then each allocated chunk |
| carries an additional check word to verify that it was malloced |
| from its space. These check words are the same within each |
| execution of a program using malloc, but differ across |
| executions, so externally crafted fake chunks cannot be |
| freed. This improves security by rejecting frees/reallocs that |
| could corrupt heap memory, in addition to the checks preventing |
| writes to statics that are always on. This may further improve |
| security at the expense of time and space overhead. (Note that |
| FOOTERS may also be worth using with MSPACES.) |
| |
| By default detected errors cause the program to abort (calling |
| "abort()"). You can override this to instead proceed past |
| errors by defining PROCEED_ON_ERROR. In this case, a bad free |
| has no effect, and a malloc that encounters a bad address |
| caused by user overwrites will ignore the bad address by |
| dropping pointers and indices to all known memory. This may |
| be appropriate for programs that should continue if at all |
| possible in the face of programming errors, although they may |
| run out of memory because dropped memory is never reclaimed. |
| |
| If you don't like either of these options, you can define |
| CORRUPTION_ERROR_ACTION and USAGE_ERROR_ACTION to do anything |
| else. And if if you are sure that your program using malloc has |
| no errors or vulnerabilities, you can define INSECURE to 1, |
| which might (or might not) provide a small performance improvement. |
| |
| It is also possible to limit the maximum total allocatable |
| space, using malloc_set_footprint_limit. This is not |
| designed as a security feature in itself (calls to set limits |
| are not screened or privileged), but may be useful as one |
| aspect of a secure implementation. |
| |
| Thread-safety: NOT thread-safe unless USE_LOCKS defined non-zero |
| When USE_LOCKS is defined, each public call to malloc, free, |
| etc is surrounded with a lock. By default, this uses a plain |
| pthread mutex, win32 critical section, or a spin-lock if if |
| available for the platform and not disabled by setting |
| USE_SPIN_LOCKS=0. However, if USE_RECURSIVE_LOCKS is defined, |
| recursive versions are used instead (which are not required for |
| base functionality but may be needed in layered extensions). |
| Using a global lock is not especially fast, and can be a major |
| bottleneck. It is designed only to provide minimal protection |
| in concurrent environments, and to provide a basis for |
| extensions. If you are using malloc in a concurrent program, |
| consider instead using nedmalloc |
| (http://www.nedprod.com/programs/portable/nedmalloc/) or |
| ptmalloc (See http://www.malloc.de), which are derived from |
| versions of this malloc. |
| |
| System requirements: Any combination of MORECORE and/or MMAP/MUNMAP |
| This malloc can use unix sbrk or any emulation (invoked using |
| the CALL_MORECORE macro) and/or mmap/munmap or any emulation |
| (invoked using CALL_MMAP/CALL_MUNMAP) to get and release system |
| memory. On most unix systems, it tends to work best if both |
| MORECORE and MMAP are enabled. On Win32, it uses emulations |
| based on VirtualAlloc. It also uses common C library functions |
| like memset. |
| |
| Compliance: I believe it is compliant with the Single Unix Specification |
| (See http://www.unix.org). Also SVID/XPG, ANSI C, and probably |
| others as well. |
| |
| * Overview of algorithms |
| |
| This is not the fastest, most space-conserving, most portable, or |
| most tunable malloc ever written. However it is among the fastest |
| while also being among the most space-conserving, portable and |
| tunable. Consistent balance across these factors results in a good |
| general-purpose allocator for malloc-intensive programs. |
| |
| In most ways, this malloc is a best-fit allocator. Generally, it |
| chooses the best-fitting existing chunk for a request, with ties |
| broken in approximately least-recently-used order. (This strategy |
| normally maintains low fragmentation.) However, for requests less |
| than 256bytes, it deviates from best-fit when there is not an |
| exactly fitting available chunk by preferring to use space adjacent |
| to that used for the previous small request, as well as by breaking |
| ties in approximately most-recently-used order. (These enhance |
| locality of series of small allocations.) And for very large requests |
| (>= 256Kb by default), it relies on system memory mapping |
| facilities, if supported. (This helps avoid carrying around and |
| possibly fragmenting memory used only for large chunks.) |
| |
| All operations (except malloc_stats and mallinfo) have execution |
| times that are bounded by a constant factor of the number of bits in |
| a size_t, not counting any clearing in calloc or copying in realloc, |
| or actions surrounding MORECORE and MMAP that have times |
| proportional to the number of non-contiguous regions returned by |
| system allocation routines, which is often just 1. In real-time |
| applications, you can optionally suppress segment traversals using |
| NO_SEGMENT_TRAVERSAL, which assures bounded execution even when |
| system allocators return non-contiguous spaces, at the typical |
| expense of carrying around more memory and increased fragmentation. |
| |
| The implementation is not very modular and seriously overuses |
| macros. Perhaps someday all C compilers will do as good a job |
| inlining modular code as can now be done by brute-force expansion, |
| but now, enough of them seem not to. |
| |
| Some compilers issue a lot of warnings about code that is |
| dead/unreachable only on some platforms, and also about intentional |
| uses of negation on unsigned types. All known cases of each can be |
| ignored. |
| |
| For a longer but out of date high-level description, see |
| http://gee.cs.oswego.edu/dl/html/malloc.html |
| |
| * MSPACES |
| If MSPACES is defined, then in addition to malloc, free, etc., |
| this file also defines mspace_malloc, mspace_free, etc. These |
| are versions of malloc routines that take an "mspace" argument |
| obtained using create_mspace, to control all internal bookkeeping. |
| If ONLY_MSPACES is defined, only these versions are compiled. |
| So if you would like to use this allocator for only some allocations, |
| and your system malloc for others, you can compile with |
| ONLY_MSPACES and then do something like... |
| static mspace mymspace = create_mspace(0,0); // for example |
| #define mymalloc(bytes) mspace_malloc(mymspace, bytes) |
| |
| (Note: If you only need one instance of an mspace, you can instead |
| use "USE_DL_PREFIX" to relabel the global malloc.) |
| |
| You can similarly create thread-local allocators by storing |
| mspaces as thread-locals. For example: |
| static __thread mspace tlms = 0; |
| void* tlmalloc(size_t bytes) { |
| if (tlms == 0) tlms = create_mspace(0, 0); |
| return mspace_malloc(tlms, bytes); |
| } |
| void tlfree(void* mem) { mspace_free(tlms, mem); } |
| |
| Unless FOOTERS is defined, each mspace is completely independent. |
| You cannot allocate from one and free to another (although |
| conformance is only weakly checked, so usage errors are not always |
| caught). If FOOTERS is defined, then each chunk carries around a tag |
| indicating its originating mspace, and frees are directed to their |
| originating spaces. Normally, this requires use of locks. |
| |
| ------------------------- Compile-time options --------------------------- |
| |
| Be careful in setting #define values for numerical constants of type |
| size_t. On some systems, literal values are not automatically extended |
| to size_t precision unless they are explicitly casted. You can also |
| use the symbolic values MAX_SIZE_T, SIZE_T_ONE, etc below. |
| |
| WIN32 default: defined if _WIN32 defined |
| Defining WIN32 sets up defaults for MS environment and compilers. |
| Otherwise defaults are for unix. Beware that there seem to be some |
| cases where this malloc might not be a pure drop-in replacement for |
| Win32 malloc: Random-looking failures from Win32 GDI API's (eg; |
| SetDIBits()) may be due to bugs in some video driver implementations |
| when pixel buffers are malloc()ed, and the region spans more than |
| one VirtualAlloc()ed region. Because dlmalloc uses a small (64Kb) |
| default granularity, pixel buffers may straddle virtual allocation |
| regions more often than when using the Microsoft allocator. You can |
| avoid this by using VirtualAlloc() and VirtualFree() for all pixel |
| buffers rather than using malloc(). If this is not possible, |
| recompile this malloc with a larger DEFAULT_GRANULARITY. Note: |
| in cases where MSC and gcc (cygwin) are known to differ on WIN32, |
| conditions use _MSC_VER to distinguish them. |
| |
| DLMALLOC_EXPORT default: extern |
| Defines how public APIs are declared. If you want to export via a |
| Windows DLL, you might define this as |
| #define DLMALLOC_EXPORT extern __declspec(dllexport) |
| If you want a POSIX ELF shared object, you might use |
| #define DLMALLOC_EXPORT extern __attribute__((visibility("default"))) |
| |
| MALLOC_ALIGNMENT default: (size_t)(2 * sizeof(void *)) |
| Controls the minimum alignment for malloc'ed chunks. It must be a |
| power of two and at least 8, even on machines for which smaller |
| alignments would suffice. It may be defined as larger than this |
| though. Note however that code and data structures are optimized for |
| the case of 8-byte alignment. |
| |
| MSPACES default: 0 (false) |
| If true, compile in support for independent allocation spaces. |
| This is only supported if HAVE_MMAP is true. |
| |
| ONLY_MSPACES default: 0 (false) |
| If true, only compile in mspace versions, not regular versions. |
| |
| USE_LOCKS default: 0 (false) |
| Causes each call to each public routine to be surrounded with |
| pthread or WIN32 mutex lock/unlock. (If set true, this can be |
| overridden on a per-mspace basis for mspace versions.) If set to a |
| non-zero value other than 1, locks are used, but their |
| implementation is left out, so lock functions must be supplied manually, |
| as described below. |
| |
| USE_SPIN_LOCKS default: 1 iff USE_LOCKS and spin locks available |
| If true, uses custom spin locks for locking. This is currently |
| supported only gcc >= 4.1, older gccs on x86 platforms, and recent |
| MS compilers. Otherwise, posix locks or win32 critical sections are |
| used. |
| |
| USE_RECURSIVE_LOCKS default: not defined |
| If defined nonzero, uses recursive (aka reentrant) locks, otherwise |
| uses plain mutexes. This is not required for malloc proper, but may |
| be needed for layered allocators such as nedmalloc. |
| |
| LOCK_AT_FORK default: not defined |
| If defined nonzero, performs pthread_atfork upon initialization |
| to initialize child lock while holding parent lock. The implementation |
| assumes that pthread locks (not custom locks) are being used. In other |
| cases, you may need to customize the implementation. |
| |
| FOOTERS default: 0 |
| If true, provide extra checking and dispatching by placing |
| information in the footers of allocated chunks. This adds |
| space and time overhead. |
| |
| INSECURE default: 0 |
| If true, omit checks for usage errors and heap space overwrites. |
| |
| USE_DL_PREFIX default: NOT defined |
| Causes compiler to prefix all public routines with the string 'dl'. |
| This can be useful when you only want to use this malloc in one part |
| of a program, using your regular system malloc elsewhere. |
| |
| MALLOC_INSPECT_ALL default: NOT defined |
| If defined, compiles malloc_inspect_all and mspace_inspect_all, that |
| perform traversal of all heap space. Unless access to these |
| functions is otherwise restricted, you probably do not want to |
| include them in secure implementations. |
| |
| ABORT default: defined as abort() |
| Defines how to abort on failed checks. On most systems, a failed |
| check cannot die with an "assert" or even print an informative |
| message, because the underlying print routines in turn call malloc, |
| which will fail again. Generally, the best policy is to simply call |
| abort(). It's not very useful to do more than this because many |
| errors due to overwriting will show up as address faults (null, odd |
| addresses etc) rather than malloc-triggered checks, so will also |
| abort. Also, most compilers know that abort() does not return, so |
| can better optimize code conditionally calling it. |
| |
| PROCEED_ON_ERROR default: defined as 0 (false) |
| Controls whether detected bad addresses cause them to bypassed |
| rather than aborting. If set, detected bad arguments to free and |
| realloc are ignored. And all bookkeeping information is zeroed out |
| upon a detected overwrite of freed heap space, thus losing the |
| ability to ever return it from malloc again, but enabling the |
| application to proceed. If PROCEED_ON_ERROR is defined, the |
| static variable malloc_corruption_error_count is compiled in |
| and can be examined to see if errors have occurred. This option |
| generates slower code than the default abort policy. |
| |
| DEBUG default: NOT defined |
| The DEBUG setting is mainly intended for people trying to modify |
| this code or diagnose problems when porting to new platforms. |
| However, it may also be able to better isolate user errors than just |
| using runtime checks. The assertions in the check routines spell |
| out in more detail the assumptions and invariants underlying the |
| algorithms. The checking is fairly extensive, and will slow down |
| execution noticeably. Calling malloc_stats or mallinfo with DEBUG |
| set will attempt to check every non-mmapped allocated and free chunk |
| in the course of computing the summaries. |
| |
| ABORT_ON_ASSERT_FAILURE default: defined as 1 (true) |
| Debugging assertion failures can be nearly impossible if your |
| version of the assert macro causes malloc to be called, which will |
| lead to a cascade of further failures, blowing the runtime stack. |
| ABORT_ON_ASSERT_FAILURE cause assertions failures to call abort(), |
| which will usually make debugging easier. |
| |
| MALLOC_FAILURE_ACTION default: sets errno to ENOMEM, or no-op on win32 |
| The action to take before "return 0" when malloc fails to be able to |
| return memory because there is none available. |
| |
| HAVE_MORECORE default: 1 (true) unless win32 or ONLY_MSPACES |
| True if this system supports sbrk or an emulation of it. |
| |
| MORECORE default: sbrk |
| The name of the sbrk-style system routine to call to obtain more |
| memory. See below for guidance on writing custom MORECORE |
| functions. The type of the argument to sbrk/MORECORE varies across |
| systems. It cannot be size_t, because it supports negative |
| arguments, so it is normally the signed type of the same width as |
| size_t (sometimes declared as "intptr_t"). It doesn't much matter |
| though. Internally, we only call it with arguments less than half |
| the max value of a size_t, which should work across all reasonable |
| possibilities, although sometimes generating compiler warnings. |
| |
| MORECORE_CONTIGUOUS default: 1 (true) if HAVE_MORECORE |
| If true, take advantage of fact that consecutive calls to MORECORE |
| with positive arguments always return contiguous increasing |
| addresses. This is true of unix sbrk. It does not hurt too much to |
| set it true anyway, since malloc copes with non-contiguities. |
| Setting it false when definitely non-contiguous saves time |
| and possibly wasted space it would take to discover this though. |
| |
| MORECORE_CANNOT_TRIM default: NOT defined |
| True if MORECORE cannot release space back to the system when given |
| negative arguments. This is generally necessary only if you are |
| using a hand-crafted MORECORE function that cannot handle negative |
| arguments. |
| |
| NO_SEGMENT_TRAVERSAL default: 0 |
| If non-zero, suppresses traversals of memory segments |
| returned by either MORECORE or CALL_MMAP. This disables |
| merging of segments that are contiguous, and selectively |
| releasing them to the OS if unused, but bounds execution times. |
| |
| HAVE_MMAP default: 1 (true) |
| True if this system supports mmap or an emulation of it. If so, and |
| HAVE_MORECORE is not true, MMAP is used for all system |
| allocation. If set and HAVE_MORECORE is true as well, MMAP is |
| primarily used to directly allocate very large blocks. It is also |
| used as a backup strategy in cases where MORECORE fails to provide |
| space from system. Note: A single call to MUNMAP is assumed to be |
| able to unmap memory that may have be allocated using multiple calls |
| to MMAP, so long as they are adjacent. |
| |
| HAVE_MREMAP default: 1 on linux, else 0 |
| If true realloc() uses mremap() to re-allocate large blocks and |
| extend or shrink allocation spaces. |
| |
| MMAP_CLEARS default: 1 except on WINCE. |
| True if mmap clears memory so calloc doesn't need to. This is true |
| for standard unix mmap using /dev/zero and on WIN32 except for WINCE. |
| |
| USE_BUILTIN_FFS default: 0 (i.e., not used) |
| Causes malloc to use the builtin ffs() function to compute indices. |
| Some compilers may recognize and intrinsify ffs to be faster than the |
| supplied C version. Also, the case of x86 using gcc is special-cased |
| to an asm instruction, so is already as fast as it can be, and so |
| this setting has no effect. Similarly for Win32 under recent MS compilers. |
| (On most x86s, the asm version is only slightly faster than the C version.) |
| |
| malloc_getpagesize default: derive from system includes, or 4096. |
| The system page size. To the extent possible, this malloc manages |
| memory from the system in page-size units. This may be (and |
| usually is) a function rather than a constant. This is ignored |
| if WIN32, where page size is determined using getSystemInfo during |
| initialization. |
| |
| USE_DEV_RANDOM default: 0 (i.e., not used) |
| Causes malloc to use /dev/random to initialize secure magic seed for |
| stamping footers. Otherwise, the current time is used. |
| |
| NO_MALLINFO default: 0 |
| If defined, don't compile "mallinfo". This can be a simple way |
| of dealing with mismatches between system declarations and |
| those in this file. |
| |
| MALLINFO_FIELD_TYPE default: size_t |
| The type of the fields in the mallinfo struct. This was originally |
| defined as "int" in SVID etc, but is more usefully defined as |
| size_t. The value is used only if HAVE_USR_INCLUDE_MALLOC_H is not set |
| |
| NO_MALLOC_STATS default: 0 |
| If defined, don't compile "malloc_stats". This avoids calls to |
| fprintf and bringing in stdio dependencies you might not want. |
| |
| REALLOC_ZERO_BYTES_FREES default: not defined |
| This should be set if a call to realloc with zero bytes should |
| be the same as a call to free. Some people think it should. Otherwise, |
| since this malloc returns a unique pointer for malloc(0), so does |
| realloc(p, 0). |
| |
| LACKS_UNISTD_H, LACKS_FCNTL_H, LACKS_SYS_PARAM_H, LACKS_SYS_MMAN_H |
| LACKS_STRINGS_H, LACKS_STRING_H, LACKS_SYS_TYPES_H, LACKS_ERRNO_H |
| LACKS_STDLIB_H LACKS_SCHED_H LACKS_TIME_H default: NOT defined unless on WIN32 |
| Define these if your system does not have these header files. |
| You might need to manually insert some of the declarations they provide. |
| |
| DEFAULT_GRANULARITY default: page size if MORECORE_CONTIGUOUS, |
| system_info.dwAllocationGranularity in WIN32, |
| otherwise 64K. |
| Also settable using mallopt(M_GRANULARITY, x) |
| The unit for allocating and deallocating memory from the system. On |
| most systems with contiguous MORECORE, there is no reason to |
| make this more than a page. However, systems with MMAP tend to |
| either require or encourage larger granularities. You can increase |
| this value to prevent system allocation functions to be called so |
| often, especially if they are slow. The value must be at least one |
| page and must be a power of two. Setting to 0 causes initialization |
| to either page size or win32 region size. (Note: In previous |
| versions of malloc, the equivalent of this option was called |
| "TOP_PAD") |
| |
| DEFAULT_TRIM_THRESHOLD default: 2MB |
| Also settable using mallopt(M_TRIM_THRESHOLD, x) |
| The maximum amount of unused top-most memory to keep before |
| releasing via malloc_trim in free(). Automatic trimming is mainly |
| useful in long-lived programs using contiguous MORECORE. Because |
| trimming via sbrk can be slow on some systems, and can sometimes be |
| wasteful (in cases where programs immediately afterward allocate |
| more large chunks) the value should be high enough so that your |
| overall system performance would improve by releasing this much |
| memory. As a rough guide, you might set to a value close to the |
| average size of a process (program) running on your system. |
| Releasing this much memory would allow such a process to run in |
| memory. Generally, it is worth tuning trim thresholds when a |
| program undergoes phases where several large chunks are allocated |
| and released in ways that can reuse each other's storage, perhaps |
| mixed with phases where there are no such chunks at all. The trim |
| value must be greater than page size to have any useful effect. To |
| disable trimming completely, you can set to MAX_SIZE_T. Note that the trick |
| some people use of mallocing a huge space and then freeing it at |
| program startup, in an attempt to reserve system memory, doesn't |
| have the intended effect under automatic trimming, since that memory |
| will immediately be returned to the system. |
| |
| DEFAULT_MMAP_THRESHOLD default: 256K |
| Also settable using mallopt(M_MMAP_THRESHOLD, x) |
| The request size threshold for using MMAP to directly service a |
| request. Requests of at least this size that cannot be allocated |
| using already-existing space will be serviced via mmap. (If enough |
| normal freed space already exists it is used instead.) Using mmap |
| segregates relatively large chunks of memory so that they can be |
| individually obtained and released from the host system. A request |
| serviced through mmap is never reused by any other request (at least |
| not directly; the system may just so happen to remap successive |
| requests to the same locations). Segregating space in this way has |
| the benefits that: Mmapped space can always be individually released |
| back to the system, which helps keep the system level memory demands |
| of a long-lived program low. Also, mapped memory doesn't become |
| `locked' between other chunks, as can happen with normally allocated |
| chunks, which means that even trimming via malloc_trim would not |
| release them. However, it has the disadvantage that the space |
| cannot be reclaimed, consolidated, and then used to service later |
| requests, as happens with normal chunks. The advantages of mmap |
| nearly always outweigh disadvantages for "large" chunks, but the |
| value of "large" may vary across systems. The default is an |
| empirically derived value that works well in most systems. You can |
| disable mmap by setting to MAX_SIZE_T. |
| |
| MAX_RELEASE_CHECK_RATE default: 4095 unless not HAVE_MMAP |
| The number of consolidated frees between checks to release |
| unused segments when freeing. When using non-contiguous segments, |
| especially with multiple mspaces, checking only for topmost space |
| doesn't always suffice to trigger trimming. To compensate for this, |
| free() will, with a period of MAX_RELEASE_CHECK_RATE (or the |
| current number of segments, if greater) try to release unused |
| segments to the OS when freeing chunks that result in |
| consolidation. The best value for this parameter is a compromise |
| between slowing down frees with relatively costly checks that |
| rarely trigger versus holding on to unused memory. To effectively |
| disable, set to MAX_SIZE_T. This may lead to a very slight speed |
| improvement at the expense of carrying around more memory. |
| */ |
| |
| /* Version identifier to allow people to support multiple versions */ |
| #ifndef DLMALLOC_VERSION |
| #define DLMALLOC_VERSION 20806 |
| #endif /* DLMALLOC_VERSION */ |
| |
| #ifndef DLMALLOC_EXPORT |
| #define DLMALLOC_EXPORT extern |
| #endif |
| |
| #if defined(STARBOARD) |
| // Just make sure we don't detect as these other platforms. |
| #elif defined(__LB_SHELL__) |
| #include <time.h> |
| |
| #if defined(__LB_XB1__) || defined(__LB_XB360__) |
| // We don't want dlmalloc's WIN32, but |
| // we do need some Windows types. |
| #include <windows.h> |
| #undef WIN32 |
| #endif // __LB_XB1__ || __LB_XB360__ |
| #else // defined(STARBOARD) |
| |
| #ifndef WIN32 |
| #if defined(_WIN32) && !defined(__LB_XB1__) && !defined(__LB_XB360__) |
| #define WIN32 1 |
| #endif /* _WIN32 */ |
| #ifdef _WIN32_WCE |
| #define LACKS_FCNTL_H |
| #define WIN32 1 |
| #endif /* _WIN32_WCE */ |
| #endif /* WIN32 */ |
| #if defined(WIN32) && !defined(__LB_XB1__) && !defined(__LB_XB360__) |
| #define WIN32_LEAN_AND_MEAN |
| #include <windows.h> |
| #include <tchar.h> |
| #define HAVE_MMAP 1 |
| #define HAVE_MORECORE 0 |
| #define LACKS_UNISTD_H |
| #define LACKS_SYS_PARAM_H |
| #define LACKS_SYS_MMAN_H |
| #define LACKS_STRING_H |
| #define LACKS_STRINGS_H |
| #define LACKS_SYS_TYPES_H |
| #define LACKS_ERRNO_H |
| #define LACKS_SCHED_H |
| #ifndef MALLOC_FAILURE_ACTION |
| #define MALLOC_FAILURE_ACTION |
| #endif /* MALLOC_FAILURE_ACTION */ |
| #ifndef MMAP_CLEARS |
| #ifdef _WIN32_WCE /* WINCE reportedly does not clear */ |
| #define MMAP_CLEARS 0 |
| #else |
| #define MMAP_CLEARS 1 |
| #endif /* _WIN32_WCE */ |
| #endif /*MMAP_CLEARS */ |
| #endif /* WIN32 */ |
| |
| #if defined(DARWIN) || defined(_DARWIN) |
| /* Mac OSX docs advise not to use sbrk; it seems better to use mmap */ |
| #ifndef HAVE_MORECORE |
| #define HAVE_MORECORE 0 |
| #define HAVE_MMAP 1 |
| /* OSX allocators provide 16 byte alignment */ |
| #ifndef MALLOC_ALIGNMENT |
| #define MALLOC_ALIGNMENT ((size_t)16U) |
| #endif |
| #endif /* HAVE_MORECORE */ |
| #endif /* DARWIN */ |
| |
| #ifndef LACKS_SYS_TYPES_H |
| #include <sys/types.h> /* For size_t */ |
| #endif /* LACKS_SYS_TYPES_H */ |
| #endif // defined(STARBOARD) |
| |
| #if defined(STARBOARD) |
| #include "dlmalloc_config.h" |
| #include "starboard/common/log.h" |
| #include "starboard/configuration_constants.h" |
| #include "starboard/memory.h" |
| #include "starboard/string.h" |
| #include "starboard/system.h" |
| #ifdef MAX |
| #undef MAX |
| #endif |
| #define MAX(a, b) (((a) > (b)) ? (a) : (b)) |
| #define ABORT \ |
| do { \ |
| SbLogFormatF("%s:%s:%d - ABORT\n", __FUNCTION__, __FILE__, __LINE__); \ |
| SbSystemBreakIntoDebugger(); \ |
| } while(false) |
| #define CRASH() ABORT |
| #define fprintf(stderr, format, ...) SbLogFormatF(format, __VA_ARGS__) |
| #elif defined(__LB_SHELL__) |
| #include "dlmalloc_config.h" |
| #include "lb_memory_debug_platform.h" |
| #ifdef MAX |
| #undef MAX |
| #endif |
| #define MAX(a, b) (((a) > (b)) ? (a) : (b)) |
| |
| #define CRASH() ((void(*)())0)() |
| #endif // defined(STARBOARD) |
| |
| /* The maximum possible size_t value has all bits set */ |
| #define MAX_SIZE_T (~(size_t)0) |
| |
| #ifndef USE_LOCKS /* ensure true if spin or recursive locks set */ |
| #define USE_LOCKS ((defined(USE_SPIN_LOCKS) && USE_SPIN_LOCKS != 0) || \ |
| (defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0)) |
| #endif /* USE_LOCKS */ |
| |
| #if USE_LOCKS /* Spin locks for gcc >= 4.1, older gcc on x86, MSC >= 1310 */ |
| #if ((defined(__GNUC__) && \ |
| ((__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)) || \ |
| defined(__i386__) || defined(__x86_64__))) || \ |
| (defined(_MSC_VER) && _MSC_VER>=1310)) |
| #ifndef USE_SPIN_LOCKS |
| #define USE_SPIN_LOCKS 1 |
| #endif /* USE_SPIN_LOCKS */ |
| #elif USE_SPIN_LOCKS |
| #error "USE_SPIN_LOCKS defined without implementation" |
| #endif /* ... locks available... */ |
| #elif !defined(USE_SPIN_LOCKS) |
| #define USE_SPIN_LOCKS 0 |
| #endif /* USE_LOCKS */ |
| |
| #ifndef ONLY_MSPACES |
| #define ONLY_MSPACES 0 |
| #endif /* ONLY_MSPACES */ |
| #ifndef MSPACES |
| #if ONLY_MSPACES |
| #define MSPACES 1 |
| #else /* ONLY_MSPACES */ |
| #define MSPACES 0 |
| #endif /* ONLY_MSPACES */ |
| #endif /* MSPACES */ |
| #ifndef MALLOC_ALIGNMENT |
| #define MALLOC_ALIGNMENT ((size_t)(2 * sizeof(void *))) |
| #endif /* MALLOC_ALIGNMENT */ |
| #ifndef FOOTERS |
| #define FOOTERS 0 |
| #endif /* FOOTERS */ |
| #ifndef ABORT |
| #define ABORT abort() |
| #endif /* ABORT */ |
| #ifndef ABORT_ON_ASSERT_FAILURE |
| #define ABORT_ON_ASSERT_FAILURE 1 |
| #endif /* ABORT_ON_ASSERT_FAILURE */ |
| #ifndef PROCEED_ON_ERROR |
| #define PROCEED_ON_ERROR 0 |
| #endif /* PROCEED_ON_ERROR */ |
| |
| #ifndef INSECURE |
| #define INSECURE 0 |
| #endif /* INSECURE */ |
| #ifndef MALLOC_INSPECT_ALL |
| #define MALLOC_INSPECT_ALL 0 |
| #endif /* MALLOC_INSPECT_ALL */ |
| #ifndef HAVE_MMAP |
| #define HAVE_MMAP 1 |
| #endif /* HAVE_MMAP */ |
| #ifndef MMAP_CLEARS |
| #define MMAP_CLEARS 1 |
| #endif /* MMAP_CLEARS */ |
| #ifndef HAVE_MREMAP |
| #ifdef linux |
| #define HAVE_MREMAP 1 |
| #define _GNU_SOURCE /* Turns on mremap() definition */ |
| #else /* linux */ |
| #define HAVE_MREMAP 0 |
| #endif /* linux */ |
| #endif /* HAVE_MREMAP */ |
| #ifndef MALLOC_FAILURE_ACTION |
| #define MALLOC_FAILURE_ACTION errno = ENOMEM; |
| #endif /* MALLOC_FAILURE_ACTION */ |
| #ifndef HAVE_MORECORE |
| #if ONLY_MSPACES |
| #define HAVE_MORECORE 0 |
| #else /* ONLY_MSPACES */ |
| #define HAVE_MORECORE 1 |
| #endif /* ONLY_MSPACES */ |
| #endif /* HAVE_MORECORE */ |
| #if !HAVE_MORECORE |
| #define MORECORE_CONTIGUOUS 0 |
| #else /* !HAVE_MORECORE */ |
| #define MORECORE_DEFAULT sbrk |
| #ifndef MORECORE_CONTIGUOUS |
| #define MORECORE_CONTIGUOUS 1 |
| #endif /* MORECORE_CONTIGUOUS */ |
| #endif /* HAVE_MORECORE */ |
| #ifndef DEFAULT_GRANULARITY |
| #if (MORECORE_CONTIGUOUS || defined(WIN32) || defined(STARBOARD)) |
| #define DEFAULT_GRANULARITY (0) /* 0 means to compute in init_mparams */ |
| #else /* MORECORE_CONTIGUOUS */ |
| #define DEFAULT_GRANULARITY ((size_t)64U * (size_t)1024U) |
| #endif /* MORECORE_CONTIGUOUS */ |
| #endif /* DEFAULT_GRANULARITY */ |
| #ifndef DEFAULT_TRIM_THRESHOLD |
| #ifndef MORECORE_CANNOT_TRIM |
| #define DEFAULT_TRIM_THRESHOLD ((size_t)2U * (size_t)1024U * (size_t)1024U) |
| #else /* MORECORE_CANNOT_TRIM */ |
| #define DEFAULT_TRIM_THRESHOLD MAX_SIZE_T |
| #endif /* MORECORE_CANNOT_TRIM */ |
| #endif /* DEFAULT_TRIM_THRESHOLD */ |
| #ifndef DEFAULT_MMAP_THRESHOLD |
| #if HAVE_MMAP |
| #define DEFAULT_MMAP_THRESHOLD ((size_t)256U * (size_t)1024U) |
| #else /* HAVE_MMAP */ |
| #define DEFAULT_MMAP_THRESHOLD MAX_SIZE_T |
| #endif /* HAVE_MMAP */ |
| #endif /* DEFAULT_MMAP_THRESHOLD */ |
| #ifndef MAX_RELEASE_CHECK_RATE |
| #if HAVE_MMAP |
| #define MAX_RELEASE_CHECK_RATE 4095 |
| #else |
| #define MAX_RELEASE_CHECK_RATE MAX_SIZE_T |
| #endif /* HAVE_MMAP */ |
| #endif /* MAX_RELEASE_CHECK_RATE */ |
| #ifndef USE_BUILTIN_FFS |
| #define USE_BUILTIN_FFS 0 |
| #endif /* USE_BUILTIN_FFS */ |
| #ifndef USE_DEV_RANDOM |
| #define USE_DEV_RANDOM 0 |
| #endif /* USE_DEV_RANDOM */ |
| #ifndef NO_MALLINFO |
| #define NO_MALLINFO 0 |
| #endif /* NO_MALLINFO */ |
| #ifndef MALLINFO_FIELD_TYPE |
| #define MALLINFO_FIELD_TYPE size_t |
| #endif /* MALLINFO_FIELD_TYPE */ |
| #ifndef NO_MALLOC_STATS |
| #define NO_MALLOC_STATS 0 |
| #endif /* NO_MALLOC_STATS */ |
| #ifndef NO_SEGMENT_TRAVERSAL |
| #define NO_SEGMENT_TRAVERSAL 0 |
| #endif /* NO_SEGMENT_TRAVERSAL */ |
| |
| /* |
| mallopt tuning options. SVID/XPG defines four standard parameter |
| numbers for mallopt, normally defined in malloc.h. None of these |
| are used in this malloc, so setting them has no effect. But this |
| malloc does support the following options. |
| */ |
| |
| #define M_TRIM_THRESHOLD (-1) |
| #define M_GRANULARITY (-2) |
| #define M_MMAP_THRESHOLD (-3) |
| |
| /* ------------------------ Mallinfo declarations ------------------------ */ |
| |
| #if !NO_MALLINFO |
| /* |
| This version of malloc supports the standard SVID/XPG mallinfo |
| routine that returns a struct containing usage properties and |
| statistics. It should work on any system that has a |
| /usr/include/malloc.h defining struct mallinfo. The main |
| declaration needed is the mallinfo struct that is returned (by-copy) |
| by mallinfo(). The malloinfo struct contains a bunch of fields that |
| are not even meaningful in this version of malloc. These fields are |
| are instead filled by mallinfo() with other numbers that might be of |
| interest. |
| |
| HAVE_USR_INCLUDE_MALLOC_H should be set if you have a |
| /usr/include/malloc.h file that includes a declaration of struct |
| mallinfo. If so, it is included; else a compliant version is |
| declared below. These must be precisely the same for mallinfo() to |
| work. The original SVID version of this struct, defined on most |
| systems with mallinfo, declares all fields as ints. But some others |
| define as unsigned long. If your system defines the fields using a |
| type of different width than listed here, you MUST #include your |
| system version and #define HAVE_USR_INCLUDE_MALLOC_H. |
| */ |
| |
| /* #define HAVE_USR_INCLUDE_MALLOC_H */ |
| |
| #ifdef HAVE_USR_INCLUDE_MALLOC_H |
| #include "/usr/include/malloc.h" |
| #else /* HAVE_USR_INCLUDE_MALLOC_H */ |
| #ifndef STRUCT_MALLINFO_DECLARED |
| /* HP-UX (and others?) redefines mallinfo unless _STRUCT_MALLINFO is defined */ |
| #define _STRUCT_MALLINFO |
| #define STRUCT_MALLINFO_DECLARED 1 |
| struct mallinfo { |
| MALLINFO_FIELD_TYPE arena; /* non-mmapped space allocated from system */ |
| MALLINFO_FIELD_TYPE ordblks; /* number of free chunks */ |
| MALLINFO_FIELD_TYPE smblks; /* always 0 */ |
| MALLINFO_FIELD_TYPE hblks; /* always 0 */ |
| MALLINFO_FIELD_TYPE hblkhd; /* space in mmapped regions */ |
| MALLINFO_FIELD_TYPE usmblks; /* maximum total allocated space */ |
| MALLINFO_FIELD_TYPE fsmblks; /* always 0 */ |
| MALLINFO_FIELD_TYPE uordblks; /* total allocated space */ |
| MALLINFO_FIELD_TYPE fordblks; /* total free space */ |
| MALLINFO_FIELD_TYPE keepcost; /* releasable (via malloc_trim) space */ |
| }; |
| #endif /* STRUCT_MALLINFO_DECLARED */ |
| #endif /* HAVE_USR_INCLUDE_MALLOC_H */ |
| #endif /* NO_MALLINFO */ |
| |
| /* |
| Try to persuade compilers to inline. The most critical functions for |
| inlining are defined as macros, so these aren't used for them. |
| */ |
| |
| #ifndef FORCEINLINE |
| #if defined(__GNUC__) |
| #define FORCEINLINE __inline __attribute__ ((always_inline)) |
| #elif defined(_MSC_VER) |
| #define FORCEINLINE __forceinline |
| #endif |
| #elif defined(__LB_XB360__) |
| #undef FORCEINLINE |
| #define FORCEINLINE __forceinline |
| #endif |
| #ifndef NOINLINE |
| #if defined(__GNUC__) |
| #define NOINLINE __attribute__ ((noinline)) |
| #elif defined(_MSC_VER) |
| #define NOINLINE __declspec(noinline) |
| #else |
| #define NOINLINE |
| #endif |
| #endif |
| |
| #ifdef __cplusplus |
| extern "C" { |
| #ifndef FORCEINLINE |
| #define FORCEINLINE inline |
| #endif |
| #endif /* __cplusplus */ |
| #ifndef FORCEINLINE |
| #define FORCEINLINE |
| #endif |
| |
| #if !ONLY_MSPACES |
| |
| /* ------------------- Declarations of public routines ------------------- */ |
| |
| #ifndef USE_DL_PREFIX |
| #define dlcalloc calloc |
| #define dlfree free |
| #define dlmalloc malloc |
| #define dlmemalign memalign |
| #define dlposix_memalign posix_memalign |
| #define dlrealloc realloc |
| #define dlrealloc_in_place realloc_in_place |
| #define dlvalloc valloc |
| #define dlpvalloc pvalloc |
| #define dlmallinfo mallinfo |
| #define dlmallopt mallopt |
| #define dlmalloc_trim malloc_trim |
| #define dlmalloc_stats malloc_stats |
| #define dlmalloc_usable_size malloc_usable_size |
| #define dlmalloc_footprint malloc_footprint |
| #define dlmalloc_max_footprint malloc_max_footprint |
| #define dlmalloc_footprint_limit malloc_footprint_limit |
| #define dlmalloc_set_footprint_limit malloc_set_footprint_limit |
| #define dlmalloc_inspect_all malloc_inspect_all |
| #define dlindependent_calloc independent_calloc |
| #define dlindependent_comalloc independent_comalloc |
| #define dlbulk_free bulk_free |
| #endif /* USE_DL_PREFIX */ |
| |
| /* |
| malloc(size_t n) |
| Returns a pointer to a newly allocated chunk of at least n bytes, or |
| null if no space is available, in which case errno is set to ENOMEM |
| on ANSI C systems. |
| |
| If n is zero, malloc returns a minimum-sized chunk. (The minimum |
| size is 16 bytes on most 32bit systems, and 32 bytes on 64bit |
| systems.) Note that size_t is an unsigned type, so calls with |
| arguments that would be negative if signed are interpreted as |
| requests for huge amounts of space, which will often fail. The |
| maximum supported value of n differs across systems, but is in all |
| cases less than the maximum representable value of a size_t. |
| */ |
| DLMALLOC_EXPORT void* dlmalloc(size_t); |
| |
| /* |
| free(void* p) |
| Releases the chunk of memory pointed to by p, that had been previously |
| allocated using malloc or a related routine such as realloc. |
| It has no effect if p is null. If p was not malloced or already |
| freed, free(p) will by default cause the current program to abort. |
| */ |
| DLMALLOC_EXPORT void dlfree(void*); |
| |
| /* |
| calloc(size_t n_elements, size_t element_size); |
| Returns a pointer to n_elements * element_size bytes, with all locations |
| set to zero. |
| */ |
| DLMALLOC_EXPORT void* dlcalloc(size_t, size_t); |
| |
| /* |
| realloc(void* p, size_t n) |
| Returns a pointer to a chunk of size n that contains the same data |
| as does chunk p up to the minimum of (n, p's size) bytes, or null |
| if no space is available. |
| |
| The returned pointer may or may not be the same as p. The algorithm |
| prefers extending p in most cases when possible, otherwise it |
| employs the equivalent of a malloc-copy-free sequence. |
| |
| If p is null, realloc is equivalent to malloc. |
| |
| If space is not available, realloc returns null, errno is set (if on |
| ANSI) and p is NOT freed. |
| |
| if n is for fewer bytes than already held by p, the newly unused |
| space is lopped off and freed if possible. realloc with a size |
| argument of zero (re)allocates a minimum-sized chunk. |
| |
| The old unix realloc convention of allowing the last-free'd chunk |
| to be used as an argument to realloc is not supported. |
| */ |
| DLMALLOC_EXPORT void* dlrealloc(void*, size_t); |
| |
| /* |
| realloc_in_place(void* p, size_t n) |
| Resizes the space allocated for p to size n, only if this can be |
| done without moving p (i.e., only if there is adjacent space |
| available if n is greater than p's current allocated size, or n is |
| less than or equal to p's size). This may be used instead of plain |
| realloc if an alternative allocation strategy is needed upon failure |
| to expand space; for example, reallocation of a buffer that must be |
| memory-aligned or cleared. You can use realloc_in_place to trigger |
| these alternatives only when needed. |
| |
| Returns p if successful; otherwise null. |
| */ |
| DLMALLOC_EXPORT void* dlrealloc_in_place(void*, size_t); |
| |
| /* |
| memalign(size_t alignment, size_t n); |
| Returns a pointer to a newly allocated chunk of n bytes, aligned |
| in accord with the alignment argument. |
| |
| The alignment argument should be a power of two. If the argument is |
| not a power of two, the nearest greater power is used. |
| 8-byte alignment is guaranteed by normal malloc calls, so don't |
| bother calling memalign with an argument of 8 or less. |
| |
| Overreliance on memalign is a sure way to fragment space. |
| */ |
| DLMALLOC_EXPORT void* dlmemalign(size_t, size_t); |
| |
| /* |
| int posix_memalign(void** pp, size_t alignment, size_t n); |
| Allocates a chunk of n bytes, aligned in accord with the alignment |
| argument. Differs from memalign only in that it (1) assigns the |
| allocated memory to *pp rather than returning it, (2) fails and |
| returns EINVAL if the alignment is not a power of two (3) fails and |
| returns ENOMEM if memory cannot be allocated. |
| */ |
| DLMALLOC_EXPORT int dlposix_memalign(void**, size_t, size_t); |
| |
| /* |
| valloc(size_t n); |
| Equivalent to memalign(pagesize, n), where pagesize is the page |
| size of the system. If the pagesize is unknown, 4096 is used. |
| */ |
| DLMALLOC_EXPORT void* dlvalloc(size_t); |
| |
| /* |
| mallopt(int parameter_number, int parameter_value) |
| Sets tunable parameters The format is to provide a |
| (parameter-number, parameter-value) pair. mallopt then sets the |
| corresponding parameter to the argument value if it can (i.e., so |
| long as the value is meaningful), and returns 1 if successful else |
| 0. To workaround the fact that mallopt is specified to use int, |
| not size_t parameters, the value -1 is specially treated as the |
| maximum unsigned size_t value. |
| |
| SVID/XPG/ANSI defines four standard param numbers for mallopt, |
| normally defined in malloc.h. None of these are use in this malloc, |
| so setting them has no effect. But this malloc also supports other |
| options in mallopt. See below for details. Briefly, supported |
| parameters are as follows (listed defaults are for "typical" |
| configurations). |
| |
| Symbol param # default allowed param values |
| M_TRIM_THRESHOLD -1 2*1024*1024 any (-1 disables) |
| M_GRANULARITY -2 page size any power of 2 >= page size |
| M_MMAP_THRESHOLD -3 256*1024 any (or 0 if no MMAP support) |
| */ |
| DLMALLOC_EXPORT int dlmallopt(int, int); |
| |
| /* |
| malloc_footprint(); |
| Returns the number of bytes obtained from the system. The total |
| number of bytes allocated by malloc, realloc etc., is less than this |
| value. Unlike mallinfo, this function returns only a precomputed |
| result, so can be called frequently to monitor memory consumption. |
| Even if locks are otherwise defined, this function does not use them, |
| so results might not be up to date. |
| */ |
| DLMALLOC_EXPORT size_t dlmalloc_footprint(void); |
| |
| /* |
| malloc_max_footprint(); |
| Returns the maximum number of bytes obtained from the system. This |
| value will be greater than current footprint if deallocated space |
| has been reclaimed by the system. The peak number of bytes allocated |
| by malloc, realloc etc., is less than this value. Unlike mallinfo, |
| this function returns only a precomputed result, so can be called |
| frequently to monitor memory consumption. Even if locks are |
| otherwise defined, this function does not use them, so results might |
| not be up to date. |
| */ |
| DLMALLOC_EXPORT size_t dlmalloc_max_footprint(void); |
| |
| /* |
| malloc_footprint_limit(); |
| Returns the number of bytes that the heap is allowed to obtain from |
| the system, returning the last value returned by |
| malloc_set_footprint_limit, or the maximum size_t value if |
| never set. The returned value reflects a permission. There is no |
| guarantee that this number of bytes can actually be obtained from |
| the system. |
| */ |
| DLMALLOC_EXPORT size_t dlmalloc_footprint_limit(); |
| |
| /* |
| malloc_set_footprint_limit(); |
| Sets the maximum number of bytes to obtain from the system, causing |
| failure returns from malloc and related functions upon attempts to |
| exceed this value. The argument value may be subject to page |
| rounding to an enforceable limit; this actual value is returned. |
| Using an argument of the maximum possible size_t effectively |
| disables checks. If the argument is less than or equal to the |
| current malloc_footprint, then all future allocations that require |
| additional system memory will fail. However, invocation cannot |
| retroactively deallocate existing used memory. |
| */ |
| DLMALLOC_EXPORT size_t dlmalloc_set_footprint_limit(size_t bytes); |
| |
| #if MALLOC_INSPECT_ALL |
| /* |
| malloc_inspect_all(void(*handler)(void *start, |
| void *end, |
| size_t used_bytes, |
| void* callback_arg), |
| void* arg); |
| Traverses the heap and calls the given handler for each managed |
| region, skipping all bytes that are (or may be) used for bookkeeping |
| purposes. Traversal does not include include chunks that have been |
| directly memory mapped. Each reported region begins at the start |
| address, and continues up to but not including the end address. The |
| first used_bytes of the region contain allocated data. If |
| used_bytes is zero, the region is unallocated. The handler is |
| invoked with the given callback argument. If locks are defined, they |
| are held during the entire traversal. It is a bad idea to invoke |
| other malloc functions from within the handler. |
| |
| For example, to count the number of in-use chunks with size greater |
| than 1000, you could write: |
| static int count = 0; |
| void count_chunks(void* start, void* end, size_t used, void* arg) { |
| if (used >= 1000) ++count; |
| } |
| then: |
| malloc_inspect_all(count_chunks, NULL); |
| |
| malloc_inspect_all is compiled only if MALLOC_INSPECT_ALL is defined. |
| */ |
| DLMALLOC_EXPORT void dlmalloc_inspect_all(void(*handler)(void*, void *, size_t, void*), |
| void* arg); |
| |
| #endif /* MALLOC_INSPECT_ALL */ |
| |
| #if !NO_MALLINFO |
| /* |
| mallinfo() |
| Returns (by copy) a struct containing various summary statistics: |
| |
| arena: current total non-mmapped bytes allocated from system |
| ordblks: the number of free chunks |
| smblks: always zero. |
| hblks: current number of mmapped regions |
| hblkhd: total bytes held in mmapped regions |
| usmblks: the maximum total allocated space. This will be greater |
| than current total if trimming has occurred. |
| fsmblks: always zero |
| uordblks: current total allocated space (normal or mmapped) |
| fordblks: total free space |
| keepcost: the maximum number of bytes that could ideally be released |
| back to system via malloc_trim. ("ideally" means that |
| it ignores page restrictions etc.) |
| |
| Because these fields are ints, but internal bookkeeping may |
| be kept as longs, the reported values may wrap around zero and |
| thus be inaccurate. |
| */ |
| DLMALLOC_EXPORT struct mallinfo dlmallinfo(void); |
| #endif /* NO_MALLINFO */ |
| |
| /* |
| independent_calloc(size_t n_elements, size_t element_size, void* chunks[]); |
| |
| independent_calloc is similar to calloc, but instead of returning a |
| single cleared space, it returns an array of pointers to n_elements |
| independent elements that can hold contents of size elem_size, each |
| of which starts out cleared, and can be independently freed, |
| realloc'ed etc. The elements are guaranteed to be adjacently |
| allocated (this is not guaranteed to occur with multiple callocs or |
| mallocs), which may also improve cache locality in some |
| applications. |
| |
| The "chunks" argument is optional (i.e., may be null, which is |
| probably the most typical usage). If it is null, the returned array |
| is itself dynamically allocated and should also be freed when it is |
| no longer needed. Otherwise, the chunks array must be of at least |
| n_elements in length. It is filled in with the pointers to the |
| chunks. |
| |
| In either case, independent_calloc returns this pointer array, or |
| null if the allocation failed. If n_elements is zero and "chunks" |
| is null, it returns a chunk representing an array with zero elements |
| (which should be freed if not wanted). |
| |
| Each element must be freed when it is no longer needed. This can be |
| done all at once using bulk_free. |
| |
| independent_calloc simplifies and speeds up implementations of many |
| kinds of pools. It may also be useful when constructing large data |
| structures that initially have a fixed number of fixed-sized nodes, |
| but the number is not known at compile time, and some of the nodes |
| may later need to be freed. For example: |
| |
| struct Node { int item; struct Node* next; }; |
| |
| struct Node* build_list() { |
| struct Node** pool; |
| int n = read_number_of_nodes_needed(); |
| if (n <= 0) return 0; |
| pool = (struct Node**)(independent_calloc(n, sizeof(struct Node), 0); |
| if (pool == 0) die(); |
| // organize into a linked list... |
| struct Node* first = pool[0]; |
| for (i = 0; i < n-1; ++i) |
| pool[i]->next = pool[i+1]; |
| free(pool); // Can now free the array (or not, if it is needed later) |
| return first; |
| } |
| */ |
| DLMALLOC_EXPORT void** dlindependent_calloc(size_t, size_t, void**); |
| |
| /* |
| independent_comalloc(size_t n_elements, size_t sizes[], void* chunks[]); |
| |
| independent_comalloc allocates, all at once, a set of n_elements |
| chunks with sizes indicated in the "sizes" array. It returns |
| an array of pointers to these elements, each of which can be |
| independently freed, realloc'ed etc. The elements are guaranteed to |
| be adjacently allocated (this is not guaranteed to occur with |
| multiple callocs or mallocs), which may also improve cache locality |
| in some applications. |
| |
| The "chunks" argument is optional (i.e., may be null). If it is null |
| the returned array is itself dynamically allocated and should also |
| be freed when it is no longer needed. Otherwise, the chunks array |
| must be of at least n_elements in length. It is filled in with the |
| pointers to the chunks. |
| |
| In either case, independent_comalloc returns this pointer array, or |
| null if the allocation failed. If n_elements is zero and chunks is |
| null, it returns a chunk representing an array with zero elements |
| (which should be freed if not wanted). |
| |
| Each element must be freed when it is no longer needed. This can be |
| done all at once using bulk_free. |
| |
| independent_comallac differs from independent_calloc in that each |
| element may have a different size, and also that it does not |
| automatically clear elements. |
| |
| independent_comalloc can be used to speed up allocation in cases |
| where several structs or objects must always be allocated at the |
| same time. For example: |
| |
| struct Head { ... } |
| struct Foot { ... } |
| |
| void send_message(char* msg) { |
| int msglen = strlen(msg); |
| size_t sizes[3] = { sizeof(struct Head), msglen, sizeof(struct Foot) }; |
| void* chunks[3]; |
| if (independent_comalloc(3, sizes, chunks) == 0) |
| die(); |
| struct Head* head = (struct Head*)(chunks[0]); |
| char* body = (char*)(chunks[1]); |
| struct Foot* foot = (struct Foot*)(chunks[2]); |
| // ... |
| } |
| |
| In general though, independent_comalloc is worth using only for |
| larger values of n_elements. For small values, you probably won't |
| detect enough difference from series of malloc calls to bother. |
| |
| Overuse of independent_comalloc can increase overall memory usage, |
| since it cannot reuse existing noncontiguous small chunks that |
| might be available for some of the elements. |
| */ |
| DLMALLOC_EXPORT void** dlindependent_comalloc(size_t, size_t*, void**); |
| |
| /* |
| bulk_free(void* array[], size_t n_elements) |
| Frees and clears (sets to null) each non-null pointer in the given |
| array. This is likely to be faster than freeing them one-by-one. |
| If footers are used, pointers that have been allocated in different |
| mspaces are not freed or cleared, and the count of all such pointers |
| is returned. For large arrays of pointers with poor locality, it |
| may be worthwhile to sort this array before calling bulk_free. |
| */ |
| DLMALLOC_EXPORT size_t dlbulk_free(void**, size_t n_elements); |
| |
| /* |
| pvalloc(size_t n); |
| Equivalent to valloc(minimum-page-that-holds(n)), that is, |
| round up n to nearest pagesize. |
| */ |
| DLMALLOC_EXPORT void* dlpvalloc(size_t); |
| |
| /* |
| malloc_trim(size_t pad); |
| |
| If possible, gives memory back to the system (via negative arguments |
| to sbrk) if there is unused memory at the `high' end of the malloc |
| pool or in unused MMAP segments. You can call this after freeing |
| large blocks of memory to potentially reduce the system-level memory |
| requirements of a program. However, it cannot guarantee to reduce |
| memory. Under some allocation patterns, some large free blocks of |
| memory will be locked between two used chunks, so they cannot be |
| given back to the system. |
| |
| The `pad' argument to malloc_trim represents the amount of free |
| trailing space to leave untrimmed. If this argument is zero, only |
| the minimum amount of memory to maintain internal data structures |
| will be left. Non-zero arguments can be supplied to maintain enough |
| trailing space to service future expected allocations without having |
| to re-obtain memory from the system. |
| |
| Malloc_trim returns 1 if it actually released any memory, else 0. |
| */ |
| DLMALLOC_EXPORT int dlmalloc_trim(size_t); |
| |
| /* |
| malloc_stats(); |
| Prints on stderr the amount of space obtained from the system (both |
| via sbrk and mmap), the maximum amount (which may be more than |
| current if malloc_trim and/or munmap got called), and the current |
| number of bytes allocated via malloc (or realloc, etc) but not yet |
| freed. Note that this is the number of bytes allocated, not the |
| number requested. It will be larger than the number requested |
| because of alignment and bookkeeping overhead. Because it includes |
| alignment wastage as being in use, this figure may be greater than |
| zero even when no user-level chunks are allocated. |
| |
| The reported current and maximum system memory can be inaccurate if |
| a program makes other calls to system memory allocation functions |
| (normally sbrk) outside of malloc. |
| |
| malloc_stats prints only the most commonly interesting statistics. |
| More information can be obtained by calling mallinfo. |
| */ |
| DLMALLOC_EXPORT void dlmalloc_stats(void); |
| |
| /* |
| malloc_usable_size(void* p); |
| |
| Returns the number of bytes you can actually use in |
| an allocated chunk, which may be more than you requested (although |
| often not) due to alignment and minimum size constraints. |
| You can use this many bytes without worrying about |
| overwriting other allocated objects. This is not a particularly great |
| programming practice. malloc_usable_size can be more useful in |
| debugging and assertions, for example: |
| |
| p = malloc(n); |
| assert(malloc_usable_size(p) >= 256); |
| */ |
| size_t dlmalloc_usable_size(void*); |
| |
| #endif /* ONLY_MSPACES */ |
| |
| #if MSPACES |
| |
| /* |
| mspace is an opaque type representing an independent |
| region of space that supports mspace_malloc, etc. |
| */ |
| typedef void* mspace; |
| |
| /* |
| create_mspace creates and returns a new independent space with the |
| given initial capacity, or, if 0, the default granularity size. It |
| returns null if there is no system memory available to create the |
| space. If argument locked is non-zero, the space uses a separate |
| lock to control access. The capacity of the space will grow |
| dynamically as needed to service mspace_malloc requests. You can |
| control the sizes of incremental increases of this space by |
| compiling with a different DEFAULT_GRANULARITY or dynamically |
| setting with mallopt(M_GRANULARITY, value). |
| */ |
| DLMALLOC_EXPORT mspace create_mspace(size_t capacity, int locked); |
| |
| /* |
| destroy_mspace destroys the given space, and attempts to return all |
| of its memory back to the system, returning the total number of |
| bytes freed. After destruction, the results of access to all memory |
| used by the space become undefined. |
| */ |
| DLMALLOC_EXPORT size_t destroy_mspace(mspace msp); |
| |
| /* |
| create_mspace_with_base uses the memory supplied as the initial base |
| of a new mspace. Part (less than 128*sizeof(size_t) bytes) of this |
| space is used for bookkeeping, so the capacity must be at least this |
| large. (Otherwise 0 is returned.) When this initial space is |
| exhausted, additional memory will be obtained from the system. |
| Destroying this space will deallocate all additionally allocated |
| space (if possible) but not the initial base. |
| */ |
| DLMALLOC_EXPORT mspace create_mspace_with_base(void* base, size_t capacity, int locked); |
| |
| /* |
| mspace_track_large_chunks controls whether requests for large chunks |
| are allocated in their own untracked mmapped regions, separate from |
| others in this mspace. By default large chunks are not tracked, |
| which reduces fragmentation. However, such chunks are not |
| necessarily released to the system upon destroy_mspace. Enabling |
| tracking by setting to true may increase fragmentation, but avoids |
| leakage when relying on destroy_mspace to release all memory |
| allocated using this space. The function returns the previous |
| setting. |
| */ |
| DLMALLOC_EXPORT int mspace_track_large_chunks(mspace msp, int enable); |
| |
| |
| /* |
| mspace_malloc behaves as malloc, but operates within |
| the given space. |
| */ |
| DLMALLOC_EXPORT void* mspace_malloc(mspace msp, size_t bytes); |
| |
| /* |
| mspace_free behaves as free, but operates within |
| the given space. |
| |
| If compiled with FOOTERS==1, mspace_free is not actually needed. |
| free may be called instead of mspace_free because freed chunks from |
| any space are handled by their originating spaces. |
| */ |
| DLMALLOC_EXPORT void mspace_free(mspace msp, void* mem); |
| |
| /* |
| mspace_realloc behaves as realloc, but operates within |
| the given space. |
| |
| If compiled with FOOTERS==1, mspace_realloc is not actually |
| needed. realloc may be called instead of mspace_realloc because |
| realloced chunks from any space are handled by their originating |
| spaces. |
| */ |
| DLMALLOC_EXPORT void* mspace_realloc(mspace msp, void* mem, size_t newsize); |
| |
| /* |
| mspace_calloc behaves as calloc, but operates within |
| the given space. |
| */ |
| DLMALLOC_EXPORT void* mspace_calloc(mspace msp, size_t n_elements, size_t elem_size); |
| |
| /* |
| mspace_memalign behaves as memalign, but operates within |
| the given space. |
| */ |
| DLMALLOC_EXPORT void* mspace_memalign(mspace msp, size_t alignment, size_t bytes); |
| |
| /* |
| mspace_independent_calloc behaves as independent_calloc, but |
| operates within the given space. |
| */ |
| DLMALLOC_EXPORT void** mspace_independent_calloc(mspace msp, size_t n_elements, |
| size_t elem_size, void* chunks[]); |
| |
| /* |
| mspace_independent_comalloc behaves as independent_comalloc, but |
| operates within the given space. |
| */ |
| DLMALLOC_EXPORT void** mspace_independent_comalloc(mspace msp, size_t n_elements, |
| size_t sizes[], void* chunks[]); |
| |
| /* |
| mspace_footprint() returns the number of bytes obtained from the |
| system for this space. |
| */ |
| DLMALLOC_EXPORT size_t mspace_footprint(mspace msp); |
| |
| /* |
| mspace_max_footprint() returns the peak number of bytes obtained from the |
| system for this space. |
| */ |
| DLMALLOC_EXPORT size_t mspace_max_footprint(mspace msp); |
| |
| |
| #if !NO_MALLINFO |
| /* |
| mspace_mallinfo behaves as mallinfo, but reports properties of |
| the given space. |
| */ |
| DLMALLOC_EXPORT struct mallinfo mspace_mallinfo(mspace msp); |
| #endif /* NO_MALLINFO */ |
| |
| /* |
| malloc_usable_size(void* p) behaves the same as malloc_usable_size; |
| */ |
| DLMALLOC_EXPORT size_t mspace_usable_size(const void* mem); |
| |
| /* |
| mspace_malloc_stats behaves as malloc_stats, but reports |
| properties of the given space. |
| */ |
| DLMALLOC_EXPORT void mspace_malloc_stats(mspace msp); |
| |
| /* |
| mspace_trim behaves as malloc_trim, but |
| operates within the given space. |
| */ |
| DLMALLOC_EXPORT int mspace_trim(mspace msp, size_t pad); |
| |
| /* |
| An alias for mallopt. |
| */ |
| DLMALLOC_EXPORT int mspace_mallopt(int, int); |
| |
| #endif /* MSPACES */ |
| |
| #ifdef __cplusplus |
| } /* end of extern "C" */ |
| #endif /* __cplusplus */ |
| |
| /* |
| ======================================================================== |
| To make a fully customizable malloc.h header file, cut everything |
| above this line, put into file malloc.h, edit to suit, and #include it |
| on the next line, as well as in programs that use this malloc. |
| ======================================================================== |
| */ |
| |
| /* #include "malloc.h" */ |
| |
| /*------------------------------ internal #includes ---------------------- */ |
| |
| #ifdef _MSC_VER |
| #pragma warning( disable : 4146 ) /* no "unsigned" warnings */ |
| #endif /* _MSC_VER */ |
| #if !NO_MALLOC_STATS && !defined(STARBOARD) |
| #include <stdio.h> /* for printing in malloc_stats */ |
| #endif /* NO_MALLOC_STATS && STARBOARD */ |
| #ifndef LACKS_ERRNO_H |
| #include <errno.h> /* for MALLOC_FAILURE_ACTION */ |
| #endif /* LACKS_ERRNO_H */ |
| #ifdef DEBUG |
| #if ABORT_ON_ASSERT_FAILURE |
| #undef assert |
| #define assert(x) if(!(x)) ABORT |
| #else /* ABORT_ON_ASSERT_FAILURE */ |
| #include <assert.h> |
| #endif /* ABORT_ON_ASSERT_FAILURE */ |
| #else /* DEBUG */ |
| #ifndef assert |
| #define assert(x) |
| #endif |
| #define DEBUG 0 |
| #endif /* DEBUG */ |
| #if !defined(WIN32) && !defined(LACKS_TIME_H) |
| #include <time.h> /* for magic initialization */ |
| #endif /* WIN32 */ |
| #ifndef LACKS_STDLIB_H |
| #include <stdlib.h> /* for abort() */ |
| #endif /* LACKS_STDLIB_H */ |
| #ifndef LACKS_STRING_H |
| #include <string.h> /* for memset etc */ |
| #endif /* LACKS_STRING_H */ |
| #if USE_BUILTIN_FFS |
| #ifndef LACKS_STRINGS_H |
| #include <strings.h> /* for ffs */ |
| #endif /* LACKS_STRINGS_H */ |
| #endif /* USE_BUILTIN_FFS */ |
| #if HAVE_MMAP |
| #ifndef LACKS_SYS_MMAN_H |
| /* On some versions of linux, mremap decl in mman.h needs __USE_GNU set */ |
| #if (defined(linux) && !defined(__USE_GNU)) |
| #define __USE_GNU 1 |
| #include <sys/mman.h> /* for mmap */ |
| #undef __USE_GNU |
| #else |
| #include <sys/mman.h> /* for mmap */ |
| #endif /* linux */ |
| #endif /* LACKS_SYS_MMAN_H */ |
| #ifndef LACKS_FCNTL_H |
| #include <fcntl.h> |
| #endif /* LACKS_FCNTL_H */ |
| #endif /* HAVE_MMAP */ |
| #ifndef LACKS_UNISTD_H |
| #include <unistd.h> /* for sbrk, sysconf */ |
| #else /* LACKS_UNISTD_H */ |
| #if !defined(__FreeBSD__) && !defined(__OpenBSD__) && !defined(__NetBSD__) |
| extern void* sbrk(ptrdiff_t); |
| #endif /* FreeBSD etc */ |
| #endif /* LACKS_UNISTD_H */ |
| |
| /* Declarations for locking */ |
| #if USE_LOCKS |
| #ifndef WIN32 |
| #if defined (__SVR4) && defined (__sun) /* solaris */ |
| #include <thread.h> |
| #elif !defined(LACKS_SCHED_H) |
| #include <sched.h> |
| #endif /* solaris or LACKS_SCHED_H */ |
| #if (defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0) || !USE_SPIN_LOCKS |
| #if !defined(STARBOARD) |
| #include <pthread.h> |
| #endif /* !STARBOARD */ |
| #endif /* USE_RECURSIVE_LOCKS ... */ |
| #elif defined(_MSC_VER) |
| #ifndef _M_AMD64 |
| /* These are already defined on AMD64 builds */ |
| #ifdef __cplusplus |
| extern "C" { |
| #endif /* __cplusplus */ |
| LONG __cdecl _InterlockedCompareExchange(LONG volatile *Dest, LONG Exchange, LONG Comp); |
| LONG __cdecl _InterlockedExchange(LONG volatile *Target, LONG Value); |
| #ifdef __cplusplus |
| } |
| #endif /* __cplusplus */ |
| #endif /* _M_AMD64 */ |
| #pragma intrinsic (_InterlockedCompareExchange) |
| #pragma intrinsic (_InterlockedExchange) |
| #define interlockedcompareexchange _InterlockedCompareExchange |
| #define interlockedexchange _InterlockedExchange |
| #elif defined(WIN32) && defined(__GNUC__) |
| #define interlockedcompareexchange(a, b, c) __sync_val_compare_and_swap(a, c, b) |
| #define interlockedexchange __sync_lock_test_and_set |
| #endif /* Win32 */ |
| #else /* USE_LOCKS */ |
| #endif /* USE_LOCKS */ |
| |
| #ifndef LOCK_AT_FORK |
| #define LOCK_AT_FORK 0 |
| #endif |
| |
| /* Declarations for bit scanning on win32 */ |
| #if defined(_MSC_VER) && _MSC_VER>=1300 && !defined(__LB_XB360__) |
| #ifndef BitScanForward /* Try to avoid pulling in WinNT.h */ |
| #ifdef __cplusplus |
| extern "C" { |
| #endif /* __cplusplus */ |
| unsigned char _BitScanForward(unsigned long *index, unsigned long mask); |
| unsigned char _BitScanReverse(unsigned long *index, unsigned long mask); |
| #ifdef __cplusplus |
| } |
| #endif /* __cplusplus */ |
| |
| #define BitScanForward _BitScanForward |
| #define BitScanReverse _BitScanReverse |
| #pragma intrinsic(_BitScanForward) |
| #pragma intrinsic(_BitScanReverse) |
| #endif /* BitScanForward */ |
| #endif /* defined(_MSC_VER) && _MSC_VER>=1300 */ |
| |
| #ifndef WIN32 |
| #ifndef malloc_getpagesize |
| # ifdef _SC_PAGESIZE /* some SVR4 systems omit an underscore */ |
| # ifndef _SC_PAGE_SIZE |
| # define _SC_PAGE_SIZE _SC_PAGESIZE |
| # endif |
| # endif |
| # ifdef _SC_PAGE_SIZE |
| # define malloc_getpagesize sysconf(_SC_PAGE_SIZE) |
| # else |
| # if defined(BSD) || defined(DGUX) || defined(HAVE_GETPAGESIZE) |
| extern size_t getpagesize(); |
| # define malloc_getpagesize getpagesize() |
| # else |
| # ifdef WIN32 /* use supplied emulation of getpagesize */ |
| # define malloc_getpagesize getpagesize() |
| # else |
| # ifndef LACKS_SYS_PARAM_H |
| # include <sys/param.h> |
| # endif |
| # ifdef EXEC_PAGESIZE |
| # define malloc_getpagesize EXEC_PAGESIZE |
| # else |
| # ifdef NBPG |
| # ifndef CLSIZE |
| # define malloc_getpagesize NBPG |
| # else |
| # define malloc_getpagesize (NBPG * CLSIZE) |
| # endif |
| # else |
| # ifdef NBPC |
| # define malloc_getpagesize NBPC |
| # else |
| # ifdef PAGESIZE |
| # define malloc_getpagesize PAGESIZE |
| # else /* just guess */ |
| # define malloc_getpagesize ((size_t)4096U) |
| # endif |
| # endif |
| # endif |
| # endif |
| # endif |
| # endif |
| # endif |
| #endif |
| #endif |
| |
| /* ------------------- size_t and alignment properties -------------------- */ |
| |
| /* The byte and bit size of a size_t */ |
| #define SIZE_T_SIZE (sizeof(size_t)) |
| #define SIZE_T_BITSIZE (sizeof(size_t) << 3) |
| |
| /* Some constants coerced to size_t */ |
| /* Annoying but necessary to avoid errors on some platforms */ |
| #define SIZE_T_ZERO ((size_t)0) |
| #define SIZE_T_ONE ((size_t)1) |
| #define SIZE_T_TWO ((size_t)2) |
| #define SIZE_T_FOUR ((size_t)4) |
| #define TWO_SIZE_T_SIZES (SIZE_T_SIZE<<1) |
| #define FOUR_SIZE_T_SIZES (SIZE_T_SIZE<<2) |
| #define SIX_SIZE_T_SIZES (FOUR_SIZE_T_SIZES+TWO_SIZE_T_SIZES) |
| #define HALF_MAX_SIZE_T (MAX_SIZE_T / 2U) |
| |
| /* The bit mask value corresponding to MALLOC_ALIGNMENT */ |
| #define CHUNK_ALIGN_MASK (MALLOC_ALIGNMENT - SIZE_T_ONE) |
| |
| /* True if address a has acceptable alignment */ |
| #define is_aligned(A) (((size_t)((A)) & (CHUNK_ALIGN_MASK)) == 0) |
| |
| /* the number of bytes to offset an address to align it */ |
| #define align_offset(A)\ |
| ((((size_t)(A) & CHUNK_ALIGN_MASK) == 0)? 0 :\ |
| ((MALLOC_ALIGNMENT - ((size_t)(A) & CHUNK_ALIGN_MASK)) & CHUNK_ALIGN_MASK)) |
| |
| /* -------------------------- MMAP preliminaries ------------------------- */ |
| |
| /* |
| If HAVE_MORECORE or HAVE_MMAP are false, we just define calls and |
| checks to fail so compiler optimizer can delete code rather than |
| using so many "#if"s. |
| */ |
| |
| |
| /* MORECORE and MMAP must return MFAIL on failure */ |
| #define MFAIL ((void*)(MAX_SIZE_T)) |
| #define CMFAIL ((char*)(MFAIL)) /* defined for convenience */ |
| |
| #if HAVE_MMAP |
| |
| #if defined(STARBOARD) |
| #define MMAP_DEFAULT(s) SbPageMapUntracked(s, kSbMemoryMapProtectReadWrite, "dlmalloc_mmap") |
| #define DIRECT_MMAP_DEFAULT(s) MMAP_DEFAULT(s) |
| #define MUNMAP_DEFAULT(a, s) (SbPageUnmapUntracked((a), (s)) ? 0 : 1) |
| |
| #elif defined (__LB_SHELL__) |
| #define MMAP_DEFAULT(s) lb_mmap_untracked(s, "dlmalloc_mmap") |
| #define DIRECT_MMAP_DEFAULT(s) MMAP_DEFAULT(s) |
| #define MUNMAP_DEFAULT(a, s) lb_munmap_untracked((a), (s)) |
| |
| #elif !defined(WIN32) |
| #define MUNMAP_DEFAULT(a, s) munmap((a), (s)) |
| #define MMAP_PROT (PROT_READ|PROT_WRITE) |
| #if !defined(MAP_ANONYMOUS) && defined(MAP_ANON) |
| #define MAP_ANONYMOUS MAP_ANON |
| #endif /* MAP_ANON */ |
| #ifdef MAP_ANONYMOUS |
| #define MMAP_FLAGS (MAP_PRIVATE|MAP_ANONYMOUS) |
| #define MMAP_DEFAULT(s) mmap(0, (s), MMAP_PROT, MMAP_FLAGS, -1, 0) |
| #else /* MAP_ANONYMOUS */ |
| /* |
| Nearly all versions of mmap support MAP_ANONYMOUS, so the following |
| is unlikely to be needed, but is supplied just in case. |
| */ |
| #define MMAP_FLAGS (MAP_PRIVATE) |
| static int dev_zero_fd = -1; /* Cached file descriptor for /dev/zero. */ |
| #define MMAP_DEFAULT(s) ((dev_zero_fd < 0) ? \ |
| (dev_zero_fd = open("/dev/zero", O_RDWR), \ |
| mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0)) : \ |
| mmap(0, (s), MMAP_PROT, MMAP_FLAGS, dev_zero_fd, 0)) |
| #endif /* MAP_ANONYMOUS */ |
| |
| #define DIRECT_MMAP_DEFAULT(s) MMAP_DEFAULT(s) |
| |
| #else /* WIN32 */ |
| |
| /* Win32 MMAP via VirtualAlloc */ |
| static FORCEINLINE void* win32mmap(size_t size) { |
| void* ptr = VirtualAlloc(0, size, MEM_RESERVE|MEM_COMMIT, PAGE_READWRITE); |
| return (ptr != 0)? ptr: MFAIL; |
| } |
| |
| /* For direct MMAP, use MEM_TOP_DOWN to minimize interference */ |
| static FORCEINLINE void* win32direct_mmap(size_t size) { |
| void* ptr = VirtualAlloc(0, size, MEM_RESERVE|MEM_COMMIT|MEM_TOP_DOWN, |
| PAGE_READWRITE); |
| return (ptr != 0)? ptr: MFAIL; |
| } |
| |
| /* This function supports releasing coalesed segments */ |
| static FORCEINLINE int win32munmap(void* ptr, size_t size) { |
| MEMORY_BASIC_INFORMATION minfo; |
| char* cptr = (char*)ptr; |
| while (size) { |
| if (VirtualQuery(cptr, &minfo, sizeof(minfo)) == 0) |
| return -1; |
| if (minfo.BaseAddress != cptr || minfo.AllocationBase != cptr || |
| minfo.State != MEM_COMMIT || minfo.RegionSize > size) |
| return -1; |
| if (VirtualFree(cptr, 0, MEM_RELEASE) == 0) |
| return -1; |
| cptr += minfo.RegionSize; |
| size -= minfo.RegionSize; |
| } |
| return 0; |
| } |
| |
| #define MMAP_DEFAULT(s) win32mmap(s) |
| #define MUNMAP_DEFAULT(a, s) win32munmap((a), (s)) |
| #define DIRECT_MMAP_DEFAULT(s) win32direct_mmap(s) |
| #endif /* WIN32 */ |
| #endif /* HAVE_MMAP */ |
| |
| #if HAVE_MREMAP |
| #ifndef WIN32 |
| #define MREMAP_DEFAULT(addr, osz, nsz, mv) mremap((addr), (osz), (nsz), (mv)) |
| #endif /* WIN32 */ |
| #endif /* HAVE_MREMAP */ |
| |
| /** |
| * Define CALL_MORECORE |
| */ |
| #if HAVE_MORECORE |
| #ifdef MORECORE |
| #define CALL_MORECORE(S) MORECORE(S) |
| #else /* MORECORE */ |
| #define CALL_MORECORE(S) MORECORE_DEFAULT(S) |
| #endif /* MORECORE */ |
| #else /* HAVE_MORECORE */ |
| #define CALL_MORECORE(S) MFAIL |
| #endif /* HAVE_MORECORE */ |
| |
| /** |
| * Define CALL_MMAP/CALL_MUNMAP/CALL_DIRECT_MMAP |
| */ |
| #if HAVE_MMAP |
| #define USE_MMAP_BIT (SIZE_T_ONE) |
| |
| #ifdef MMAP |
| #define CALL_MMAP(s) MMAP(s) |
| #else /* MMAP */ |
| #define CALL_MMAP(s) MMAP_DEFAULT(s) |
| #endif /* MMAP */ |
| #ifdef MUNMAP |
| #define CALL_MUNMAP(a, s) MUNMAP((a), (s)) |
| #else /* MUNMAP */ |
| #define CALL_MUNMAP(a, s) MUNMAP_DEFAULT((a), (s)) |
| #endif /* MUNMAP */ |
| #ifdef DIRECT_MMAP |
| #define CALL_DIRECT_MMAP(s) DIRECT_MMAP(s) |
| #else /* DIRECT_MMAP */ |
| #define CALL_DIRECT_MMAP(s) DIRECT_MMAP_DEFAULT(s) |
| #endif /* DIRECT_MMAP */ |
| #else /* HAVE_MMAP */ |
| #define USE_MMAP_BIT (SIZE_T_ZERO) |
| |
| #define MMAP(s) MFAIL |
| #define MUNMAP(a, s) (-1) |
| #define DIRECT_MMAP(s) MFAIL |
| #define CALL_DIRECT_MMAP(s) DIRECT_MMAP(s) |
| #define CALL_MMAP(s) MMAP(s) |
| #define CALL_MUNMAP(a, s) MUNMAP((a), (s)) |
| #endif /* HAVE_MMAP */ |
| |
| /** |
| * Define CALL_MREMAP |
| */ |
| #if HAVE_MMAP && HAVE_MREMAP |
| #ifdef MREMAP |
| #define CALL_MREMAP(addr, osz, nsz, mv) MREMAP((addr), (osz), (nsz), (mv)) |
| #else /* MREMAP */ |
| #define CALL_MREMAP(addr, osz, nsz, mv) MREMAP_DEFAULT((addr), (osz), (nsz), (mv)) |
| #endif /* MREMAP */ |
| #else /* HAVE_MMAP && HAVE_MREMAP */ |
| #define CALL_MREMAP(addr, osz, nsz, mv) MFAIL |
| #endif /* HAVE_MMAP && HAVE_MREMAP */ |
| |
| /* mstate bit set if continguous morecore disabled or failed */ |
| #define USE_NONCONTIGUOUS_BIT (4U) |
| |
| /* segment bit set in create_mspace_with_base */ |
| #define EXTERN_BIT (8U) |
| |
| |
| /* --------------------------- Lock preliminaries ------------------------ */ |
| |
| /* |
| When locks are defined, there is one global lock, plus |
| one per-mspace lock. |
| |
| The global lock_ensures that mparams.magic and other unique |
| mparams values are initialized only once. It also protects |
| sequences of calls to MORECORE. In many cases sys_alloc requires |
| two calls, that should not be interleaved with calls by other |
| threads. This does not protect against direct calls to MORECORE |
| by other threads not using this lock, so there is still code to |
| cope the best we can on interference. |
| |
| Per-mspace locks surround calls to malloc, free, etc. |
| By default, locks are simple non-reentrant mutexes. |
| |
| Because lock-protected regions generally have bounded times, it is |
| OK to use the supplied simple spinlocks. Spinlocks are likely to |
| improve performance for lightly contended applications, but worsen |
| performance under heavy contention. |
| |
| If USE_LOCKS is > 1, the definitions of lock routines here are |
| bypassed, in which case you will need to define the type MLOCK_T, |
| and at least INITIAL_LOCK, DESTROY_LOCK, ACQUIRE_LOCK, RELEASE_LOCK |
| and TRY_LOCK. You must also declare a |
| static MLOCK_T malloc_global_mutex = { initialization values };. |
| |
| */ |
| |
| #if !USE_LOCKS |
| #define USE_LOCK_BIT (0U) |
| #define INITIAL_LOCK(l) (0) |
| #define DESTROY_LOCK(l) (0) |
| #define ACQUIRE_MALLOC_GLOBAL_LOCK() |
| #define RELEASE_MALLOC_GLOBAL_LOCK() |
| |
| #else |
| #if USE_LOCKS > 1 |
| /* ----------------------- User-defined locks ------------------------ */ |
| /* Define your own lock implementation here */ |
| /* #define INITIAL_LOCK(lk) ... */ |
| /* #define DESTROY_LOCK(lk) ... */ |
| /* #define ACQUIRE_LOCK(lk) ... */ |
| /* #define RELEASE_LOCK(lk) ... */ |
| /* #define TRY_LOCK(lk) ... */ |
| /* static MLOCK_T malloc_global_mutex = ... */ |
| |
| // See dlmalloc_config.h for definitions of *_LOCK macros. |
| static MLOCK_T malloc_global_mutex; |
| static volatile int malloc_global_mutex_status; |
| static void init_malloc_global_mutex() { |
| if (malloc_global_mutex_status > 0) { |
| return; |
| } |
| INITIAL_LOCK(&malloc_global_mutex); |
| malloc_global_mutex_status = 1; |
| } |
| |
| #elif USE_SPIN_LOCKS |
| |
| /* First, define CAS_LOCK and CLEAR_LOCK on ints */ |
| /* Note CAS_LOCK defined to return 0 on success */ |
| |
| #if defined(__GNUC__)&& (__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 1)) |
| #define CAS_LOCK(sl) __sync_lock_test_and_set(sl, 1) |
| #define CLEAR_LOCK(sl) __sync_lock_release(sl) |
| |
| #elif (defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__))) |
| /* Custom spin locks for older gcc on x86 */ |
| static FORCEINLINE int x86_cas_lock(int *sl) { |
| int ret; |
| int val = 1; |
| int cmp = 0; |
| __asm__ __volatile__ ("lock; cmpxchgl %1, %2" |
| : "=a" (ret) |
| : "r" (val), "m" (*(sl)), "0"(cmp) |
| : "memory", "cc"); |
| return ret; |
| } |
| |
| static FORCEINLINE void x86_clear_lock(int* sl) { |
| assert(*sl != 0); |
| int prev = 0; |
| int ret; |
| __asm__ __volatile__ ("lock; xchgl %0, %1" |
| : "=r" (ret) |
| : "m" (*(sl)), "0"(prev) |
| : "memory"); |
| } |
| |
| #define CAS_LOCK(sl) x86_cas_lock(sl) |
| #define CLEAR_LOCK(sl) x86_clear_lock(sl) |
| |
| #else /* Win32 MSC */ |
| #define CAS_LOCK(sl) interlockedexchange(sl, (LONG)1) |
| #define CLEAR_LOCK(sl) interlockedexchange (sl, (LONG)0) |
| |
| #endif /* ... gcc spins locks ... */ |
| |
| /* How to yield for a spin lock */ |
| #define SPINS_PER_YIELD 63 |
| #if defined(_MSC_VER) |
| #define SLEEP_EX_DURATION 50 /* delay for yield/sleep */ |
| #define SPIN_LOCK_YIELD SleepEx(SLEEP_EX_DURATION, FALSE) |
| #elif defined (__SVR4) && defined (__sun) /* solaris */ |
| #define SPIN_LOCK_YIELD thr_yield(); |
| #elif !defined(LACKS_SCHED_H) |
| #define SPIN_LOCK_YIELD sched_yield(); |
| #else |
| #define SPIN_LOCK_YIELD |
| #endif /* ... yield ... */ |
| |
| #if !defined(USE_RECURSIVE_LOCKS) || USE_RECURSIVE_LOCKS == 0 |
| /* Plain spin locks use single word (embedded in malloc_states) */ |
| static int spin_acquire_lock(int *sl) { |
| int spins = 0; |
| while (*(volatile int *)sl != 0 || CAS_LOCK(sl)) { |
| if ((++spins & SPINS_PER_YIELD) == 0) { |
| SPIN_LOCK_YIELD; |
| } |
| } |
| return 0; |
| } |
| |
| #define MLOCK_T int |
| #define TRY_LOCK(sl) !CAS_LOCK(sl) |
| #define RELEASE_LOCK(sl) CLEAR_LOCK(sl) |
| #define ACQUIRE_LOCK(sl) (CAS_LOCK(sl)? spin_acquire_lock(sl) : 0) |
| #define INITIAL_LOCK(sl) (*sl = 0) |
| #define DESTROY_LOCK(sl) (0) |
| static MLOCK_T malloc_global_mutex = 0; |
| |
| #else /* USE_RECURSIVE_LOCKS */ |
| /* types for lock owners */ |
| #ifdef WIN32 |
| #define THREAD_ID_T DWORD |
| #define CURRENT_THREAD GetCurrentThreadId() |
| #define EQ_OWNER(X,Y) ((X) == (Y)) |
| #else |
| /* |
| Note: the following assume that pthread_t is a type that can be |
| initialized to (casted) zero. If this is not the case, you will need to |
| somehow redefine these or not use spin locks. |
| */ |
| #define THREAD_ID_T pthread_t |
| #define CURRENT_THREAD pthread_self() |
| #define EQ_OWNER(X,Y) pthread_equal(X, Y) |
| #endif |
| |
| struct malloc_recursive_lock { |
| int sl; |
| unsigned int c; |
| THREAD_ID_T threadid; |
| }; |
| |
| #define MLOCK_T struct malloc_recursive_lock |
| static MLOCK_T malloc_global_mutex = { 0, 0, (THREAD_ID_T)0}; |
| |
| static FORCEINLINE void recursive_release_lock(MLOCK_T *lk) { |
| assert(lk->sl != 0); |
| if (--lk->c == 0) { |
| CLEAR_LOCK(&lk->sl); |
| } |
| } |
| |
| static FORCEINLINE int recursive_acquire_lock(MLOCK_T *lk) { |
| THREAD_ID_T mythreadid = CURRENT_THREAD; |
| int spins = 0; |
| for (;;) { |
| if (*((volatile int *)(&lk->sl)) == 0) { |
| if (!CAS_LOCK(&lk->sl)) { |
| lk->threadid = mythreadid; |
| lk->c = 1; |
| return 0; |
| } |
| } |
| else if (EQ_OWNER(lk->threadid, mythreadid)) { |
| ++lk->c; |
| return 0; |
| } |
| if ((++spins & SPINS_PER_YIELD) == 0) { |
| SPIN_LOCK_YIELD; |
| } |
| } |
| } |
| |
| static FORCEINLINE int recursive_try_lock(MLOCK_T *lk) { |
| THREAD_ID_T mythreadid = CURRENT_THREAD; |
| if (*((volatile int *)(&lk->sl)) == 0) { |
| if (!CAS_LOCK(&lk->sl)) { |
| lk->threadid = mythreadid; |
| lk->c = 1; |
| return 1; |
| } |
| } |
| else if (EQ_OWNER(lk->threadid, mythreadid)) { |
| ++lk->c; |
| return 1; |
| } |
| return 0; |
| } |
| |
| #define RELEASE_LOCK(lk) recursive_release_lock(lk) |
| #define TRY_LOCK(lk) recursive_try_lock(lk) |
| #define ACQUIRE_LOCK(lk) recursive_acquire_lock(lk) |
| #define INITIAL_LOCK(lk) ((lk)->threadid = (THREAD_ID_T)0, (lk)->sl = 0, (lk)->c = 0) |
| #define DESTROY_LOCK(lk) (0) |
| #endif /* USE_RECURSIVE_LOCKS */ |
| |
| #elif defined(WIN32) /* Win32 critical sections */ |
| #define MLOCK_T CRITICAL_SECTION |
| #define ACQUIRE_LOCK(lk) (EnterCriticalSection(lk), 0) |
| #define RELEASE_LOCK(lk) LeaveCriticalSection(lk) |
| #define TRY_LOCK(lk) TryEnterCriticalSection(lk) |
| #define INITIAL_LOCK(lk) (!InitializeCriticalSectionAndSpinCount((lk), 0x80000000|4000)) |
| #define DESTROY_LOCK(lk) (DeleteCriticalSection(lk), 0) |
| #define NEED_GLOBAL_LOCK_INIT |
| |
| static MLOCK_T malloc_global_mutex; |
| static volatile LONG malloc_global_mutex_status; |
| |
| /* Use spin loop to initialize global lock */ |
| static void init_malloc_global_mutex() { |
| for (;;) { |
| long stat = malloc_global_mutex_status; |
| if (stat > 0) |
| return; |
| /* transition to < 0 while initializing, then to > 0) */ |
| if (stat == 0 && |
| interlockedcompareexchange(&malloc_global_mutex_status, (LONG)-1, (LONG)0) == 0) { |
| InitializeCriticalSection(&malloc_global_mutex); |
| interlockedexchange(&malloc_global_mutex_status, (LONG)1); |
| return; |
| } |
| SleepEx(0, FALSE); |
| } |
| } |
| |
| #else /* pthreads-based locks */ |
| #define MLOCK_T pthread_mutex_t |
| #define ACQUIRE_LOCK(lk) pthread_mutex_lock(lk) |
| #define RELEASE_LOCK(lk) pthread_mutex_unlock(lk) |
| #define TRY_LOCK(lk) (!pthread_mutex_trylock(lk)) |
| #define INITIAL_LOCK(lk) pthread_init_lock(lk) |
| #define DESTROY_LOCK(lk) pthread_mutex_destroy(lk) |
| |
| #if defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0 && defined(linux) && !defined(PTHREAD_MUTEX_RECURSIVE) |
| /* Cope with old-style linux recursive lock initialization by adding */ |
| /* skipped internal declaration from pthread.h */ |
| extern int pthread_mutexattr_setkind_np __P ((pthread_mutexattr_t *__attr, |
| int __kind)); |
| #define PTHREAD_MUTEX_RECURSIVE PTHREAD_MUTEX_RECURSIVE_NP |
| #define pthread_mutexattr_settype(x,y) pthread_mutexattr_setkind_np(x,y) |
| #endif /* USE_RECURSIVE_LOCKS ... */ |
| |
| static MLOCK_T malloc_global_mutex = PTHREAD_MUTEX_INITIALIZER; |
| |
| static int pthread_init_lock (MLOCK_T *lk) { |
| pthread_mutexattr_t attr; |
| if (pthread_mutexattr_init(&attr)) return 1; |
| #if defined(USE_RECURSIVE_LOCKS) && USE_RECURSIVE_LOCKS != 0 |
| if (pthread_mutexattr_settype(&attr, PTHREAD_MUTEX_RECURSIVE)) return 1; |
| #endif |
| if (pthread_mutex_init(lk, &attr)) return 1; |
| if (pthread_mutexattr_destroy(&attr)) return 1; |
| return 0; |
| } |
| |
| #endif /* ... lock types ... */ |
| |
| /* Common code for all lock types */ |
| #define USE_LOCK_BIT (2U) |
| |
| #ifndef ACQUIRE_MALLOC_GLOBAL_LOCK |
| #define ACQUIRE_MALLOC_GLOBAL_LOCK() ACQUIRE_LOCK(&malloc_global_mutex); |
| #endif |
| |
| #ifndef RELEASE_MALLOC_GLOBAL_LOCK |
| #define RELEASE_MALLOC_GLOBAL_LOCK() RELEASE_LOCK(&malloc_global_mutex); |
| #endif |
| |
| #endif /* USE_LOCKS */ |
| |
| /* ----------------------- Chunk representations ------------------------ */ |
| |
| /* |
| (The following includes lightly edited explanations by Colin Plumb.) |
| |
| The malloc_chunk declaration below is misleading (but accurate and |
| necessary). It declares a "view" into memory allowing access to |
| necessary fields at known offsets from a given base. |
| |
| Chunks of memory are maintained using a `boundary tag' method as |
| originally described by Knuth. (See the paper by Paul Wilson |
| ftp://ftp.cs.utexas.edu/pub/garbage/allocsrv.ps for a survey of such |
| techniques.) Sizes of free chunks are stored both in the front of |
| each chunk and at the end. This makes consolidating fragmented |
| chunks into bigger chunks fast. The head fields also hold bits |
| representing whether chunks are free or in use. |
| |
| Here are some pictures to make it clearer. They are "exploded" to |
| show that the state of a chunk can be thought of as extending from |
| the high 31 bits of the head field of its header through the |
| prev_foot and PINUSE_BIT bit of the following chunk header. |
| |
| A chunk that's in use looks like: |
| |
| chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | Size of previous chunk (if P = 0) | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P| |
| | Size of this chunk 1| +-+ |
| mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | | |
| +- -+ |
| | | |
| +- -+ |
| | : |
| +- size - sizeof(size_t) available payload bytes -+ |
| : | |
| chunk-> +- -+ |
| | | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |1| |
| | Size of next chunk (may or may not be in use) | +-+ |
| mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| And if it's free, it looks like this: |
| |
| chunk-> +- -+ |
| | User payload (must be in use, or we would have merged!) | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |P| |
| | Size of this chunk 0| +-+ |
| mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | Next pointer | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | Prev pointer | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | : |
| +- size - sizeof(struct chunk) unused bytes -+ |
| : | |
| chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | Size of this chunk | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |0| |
| | Size of next chunk (must be in use, or we would have merged)| +-+ |
| mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | : |
| +- User payload -+ |
| : | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |0| |
| +-+ |
| Note that since we always merge adjacent free chunks, the chunks |
| adjacent to a free chunk must be in use. |
| |
| Given a pointer to a chunk (which can be derived trivially from the |
| payload pointer) we can, in O(1) time, find out whether the adjacent |
| chunks are free, and if so, unlink them from the lists that they |
| are on and merge them with the current chunk. |
| |
| Chunks always begin on even word boundaries, so the mem portion |
| (which is returned to the user) is also on an even word boundary, and |
| thus at least double-word aligned. |
| |
| The P (PINUSE_BIT) bit, stored in the unused low-order bit of the |
| chunk size (which is always a multiple of two words), is an in-use |
| bit for the *previous* chunk. If that bit is *clear*, then the |
| word before the current chunk size contains the previous chunk |
| size, and can be used to find the front of the previous chunk. |
| The very first chunk allocated always has this bit set, preventing |
| access to non-existent (or non-owned) memory. If pinuse is set for |
| any given chunk, then you CANNOT determine the size of the |
| previous chunk, and might even get a memory addressing fault when |
| trying to do so. |
| |
| The C (CINUSE_BIT) bit, stored in the unused second-lowest bit of |
| the chunk size redundantly records whether the current chunk is |
| inuse (unless the chunk is mmapped). This redundancy enables usage |
| checks within free and realloc, and reduces indirection when freeing |
| and consolidating chunks. |
| |
| Each freshly allocated chunk must have both cinuse and pinuse set. |
| That is, each allocated chunk borders either a previously allocated |
| and still in-use chunk, or the base of its memory arena. This is |
| ensured by making all allocations from the `lowest' part of any |
| found chunk. Further, no free chunk physically borders another one, |
| so each free chunk is known to be preceded and followed by either |
| inuse chunks or the ends of memory. |
| |
| Note that the `foot' of the current chunk is actually represented |
| as the prev_foot of the NEXT chunk. This makes it easier to |
| deal with alignments etc but can be very confusing when trying |
| to extend or adapt this code. |
| |
| The exceptions to all this are |
| |
| 1. The special chunk `top' is the top-most available chunk (i.e., |
| the one bordering the end of available memory). It is treated |
| specially. Top is never included in any bin, is used only if |
| no other chunk is available, and is released back to the |
| system if it is very large (see M_TRIM_THRESHOLD). In effect, |
| the top chunk is treated as larger (and thus less well |
| fitting) than any other available chunk. The top chunk |
| doesn't update its trailing size field since there is no next |
| contiguous chunk that would have to index off it. However, |
| space is still allocated for it (TOP_FOOT_SIZE) to enable |
| separation or merging when space is extended. |
| |
| 3. Chunks allocated via mmap, have both cinuse and pinuse bits |
| cleared in their head fields. Because they are allocated |
| one-by-one, each must carry its own prev_foot field, which is |
| also used to hold the offset this chunk has within its mmapped |
| region, which is needed to preserve alignment. Each mmapped |
| chunk is trailed by the first two fields of a fake next-chunk |
| for sake of usage checks. |
| |
| */ |
| |
| struct malloc_chunk { |
| size_t prev_foot; /* Size of previous chunk (if free). */ |
| size_t head; /* Size and inuse bits. */ |
| struct malloc_chunk* fd; /* double links -- used only if free. */ |
| struct malloc_chunk* bk; |
| }; |
| |
| typedef struct malloc_chunk mchunk; |
| typedef struct malloc_chunk* mchunkptr; |
| typedef struct malloc_chunk* sbinptr; /* The type of bins of chunks */ |
| typedef unsigned int bindex_t; /* Described below */ |
| typedef unsigned int binmap_t; /* Described below */ |
| typedef unsigned int flag_t; /* The type of various bit flag sets */ |
| |
| /* ------------------- Chunks sizes and alignments ----------------------- */ |
| |
| #define MCHUNK_SIZE (sizeof(mchunk)) |
| |
| #if FOOTERS |
| #define CHUNK_OVERHEAD (TWO_SIZE_T_SIZES) |
| #else /* FOOTERS */ |
| #define CHUNK_OVERHEAD (SIZE_T_SIZE) |
| #endif /* FOOTERS */ |
| |
| /* MMapped chunks need a second word of overhead ... */ |
| #define MMAP_CHUNK_OVERHEAD (TWO_SIZE_T_SIZES) |
| /* ... and additional padding for fake next-chunk at foot */ |
| #define MMAP_FOOT_PAD (FOUR_SIZE_T_SIZES) |
| |
| /* The smallest size we can malloc is an aligned minimal chunk */ |
| #define MIN_CHUNK_SIZE\ |
| ((MCHUNK_SIZE + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK) |
| |
| /* conversion from malloc headers to user pointers, and back */ |
| #define chunk2mem(p) ((void*)((char*)(p) + TWO_SIZE_T_SIZES)) |
| #define mem2chunk(mem) ((mchunkptr)((char*)(mem) - TWO_SIZE_T_SIZES)) |
| /* chunk associated with aligned address A */ |
| #define align_as_chunk(A) (mchunkptr)((A) + align_offset(chunk2mem(A))) |
| |
| /* Bounds on request (not chunk) sizes. */ |
| #define MAX_REQUEST ((-MIN_CHUNK_SIZE) << 2) |
| #define MIN_REQUEST (MIN_CHUNK_SIZE - CHUNK_OVERHEAD - SIZE_T_ONE) |
| |
| /* pad request bytes into a usable size */ |
| #define pad_request(req) \ |
| (((req) + CHUNK_OVERHEAD + CHUNK_ALIGN_MASK) & ~CHUNK_ALIGN_MASK) |
| |
| /* pad request, checking for minimum (but not maximum) */ |
| #define request2size(req) \ |
| (((req) < MIN_REQUEST)? MIN_CHUNK_SIZE : pad_request(req)) |
| |
| |
| /* ------------------ Operations on head and foot fields ----------------- */ |
| |
| /* |
| The head field of a chunk is or'ed with PINUSE_BIT when previous |
| adjacent chunk in use, and or'ed with CINUSE_BIT if this chunk is in |
| use, unless mmapped, in which case both bits are cleared. |
| |
| FLAG4_BIT is not used by this malloc, but might be useful in extensions. |
| */ |
| |
| #define PINUSE_BIT (SIZE_T_ONE) |
| #define CINUSE_BIT (SIZE_T_TWO) |
| #define FLAG4_BIT (SIZE_T_FOUR) |
| #define INUSE_BITS (PINUSE_BIT|CINUSE_BIT) |
| #define FLAG_BITS (PINUSE_BIT|CINUSE_BIT|FLAG4_BIT) |
| |
| /* Head value for fenceposts */ |
| #define FENCEPOST_HEAD (INUSE_BITS|SIZE_T_SIZE) |
| |
| /* extraction of fields from head words */ |
| #define cinuse(p) ((p)->head & CINUSE_BIT) |
| #define pinuse(p) ((p)->head & PINUSE_BIT) |
| #define flag4inuse(p) ((p)->head & FLAG4_BIT) |
| #define is_inuse(p) (((p)->head & INUSE_BITS) != PINUSE_BIT) |
| #define is_mmapped(p) (((p)->head & INUSE_BITS) == 0) |
| |
| #define chunksize(p) ((p)->head & ~(FLAG_BITS)) |
| |
| #define clear_pinuse(p) ((p)->head &= ~PINUSE_BIT) |
| #define set_flag4(p) ((p)->head |= FLAG4_BIT) |
| #define clear_flag4(p) ((p)->head &= ~FLAG4_BIT) |
| |
| /* Treat space at ptr +/- offset as a chunk */ |
| #define chunk_plus_offset(p, s) ((mchunkptr)(((char*)(p)) + (s))) |
| #define chunk_minus_offset(p, s) ((mchunkptr)(((char*)(p)) - (s))) |
| |
| /* Ptr to next or previous physical malloc_chunk. */ |
| #define next_chunk(p) ((mchunkptr)( ((char*)(p)) + ((p)->head & ~FLAG_BITS))) |
| #define prev_chunk(p) ((mchunkptr)( ((char*)(p)) - ((p)->prev_foot) )) |
| |
| /* extract next chunk's pinuse bit */ |
| #define next_pinuse(p) ((next_chunk(p)->head) & PINUSE_BIT) |
| |
| /* Get/set size at footer */ |
| #define get_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_foot) |
| #define set_foot(p, s) (((mchunkptr)((char*)(p) + (s)))->prev_foot = (s)) |
| |
| /* Set size, pinuse bit, and foot */ |
| #define set_size_and_pinuse_of_free_chunk(p, s)\ |
| ((p)->head = (s|PINUSE_BIT), set_foot(p, s)) |
| |
| /* Set size, pinuse bit, foot, and clear next pinuse */ |
| #define set_free_with_pinuse(p, s, n)\ |
| (clear_pinuse(n), set_size_and_pinuse_of_free_chunk(p, s)) |
| |
| /* Get the internal overhead associated with chunk p */ |
| #define overhead_for(p)\ |
| (is_mmapped(p)? MMAP_CHUNK_OVERHEAD : CHUNK_OVERHEAD) |
| |
| /* Return true if malloced space is not necessarily cleared */ |
| #if MMAP_CLEARS |
| #define calloc_must_clear(p) (!is_mmapped(p)) |
| #else /* MMAP_CLEARS */ |
| #define calloc_must_clear(p) (1) |
| #endif /* MMAP_CLEARS */ |
| |
| /* ---------------------- Overlaid data structures ----------------------- */ |
| |
| /* |
| When chunks are not in use, they are treated as nodes of either |
| lists or trees. |
| |
| "Small" chunks are stored in circular doubly-linked lists, and look |
| like this: |
| |
| chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | Size of previous chunk | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| `head:' | Size of chunk, in bytes |P| |
| mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | Forward pointer to next chunk in list | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | Back pointer to previous chunk in list | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | Unused space (may be 0 bytes long) . |
| . . |
| . | |
| nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| `foot:' | Size of chunk, in bytes | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| Larger chunks are kept in a form of bitwise digital trees (aka |
| tries) keyed on chunksizes. Because malloc_tree_chunks are only for |
| free chunks greater than 256 bytes, their size doesn't impose any |
| constraints on user chunk sizes. Each node looks like: |
| |
| chunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | Size of previous chunk | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| `head:' | Size of chunk, in bytes |P| |
| mem-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | Forward pointer to next chunk of same size | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | Back pointer to previous chunk of same size | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | Pointer to left child (child[0]) | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | Pointer to right child (child[1]) | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | Pointer to parent | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | bin index of this chunk | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| | Unused space . |
| . | |
| nextchunk-> +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| `foot:' | Size of chunk, in bytes | |
| +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ |
| |
| Each tree holding treenodes is a tree of unique chunk sizes. Chunks |
| of the same size are arranged in a circularly-linked list, with only |
| the oldest chunk (the next to be used, in our FIFO ordering) |
| actually in the tree. (Tree members are distinguished by a non-null |
| parent pointer.) If a chunk with the same size an an existing node |
| is inserted, it is linked off the existing node using pointers that |
| work in the same way as fd/bk pointers of small chunks. |
| |
| Each tree contains a power of 2 sized range of chunk sizes (the |
| smallest is 0x100 <= x < 0x180), which is is divided in half at each |
| tree level, with the chunks in the smaller half of the range (0x100 |
| <= x < 0x140 for the top nose) in the left subtree and the larger |
| half (0x140 <= x < 0x180) in the right subtree. This is, of course, |
| done by inspecting individual bits. |
| |
| Using these rules, each node's left subtree contains all smaller |
| sizes than its right subtree. However, the node at the root of each |
| subtree has no particular ordering relationship to either. (The |
| dividing line between the subtree sizes is based on trie relation.) |
| If we remove the last chunk of a given size from the interior of the |
| tree, we need to replace it with a leaf node. The tree ordering |
| rules permit a node to be replaced by any leaf below it. |
| |
| The smallest chunk in a tree (a common operation in a best-fit |
| allocator) can be found by walking a path to the leftmost leaf in |
| the tree. Unlike a usual binary tree, where we follow left child |
| pointers until we reach a null, here we follow the right child |
| pointer any time the left one is null, until we reach a leaf with |
| both child pointers null. The smallest chunk in the tree will be |
| somewhere along that path. |
| |
| The worst case number of steps to add, find, or remove a node is |
| bounded by the number of bits differentiating chunks within |
| bins. Under current bin calculations, this ranges from 6 up to 21 |
| (for 32 bit sizes) or up to 53 (for 64 bit sizes). The typical case |
| is of course much better. |
| */ |
| |
| struct malloc_tree_chunk { |
| /* The first four fields must be compatible with malloc_chunk */ |
| size_t prev_foot; |
| size_t head; |
| struct malloc_tree_chunk* fd; |
| struct malloc_tree_chunk* bk; |
| |
| struct malloc_tree_chunk* child[2]; |
| struct malloc_tree_chunk* parent; |
| bindex_t index; |
| }; |
| |
| typedef struct malloc_tree_chunk tchunk; |
| typedef struct malloc_tree_chunk* tchunkptr; |
| typedef struct malloc_tree_chunk* tbinptr; /* The type of bins of trees */ |
| |
| /* A little helper macro for trees */ |
| #define leftmost_child(t) ((t)->child[0] != 0? (t)->child[0] : (t)->child[1]) |
| |
| /* ----------------------------- Segments -------------------------------- */ |
| |
| /* |
| Each malloc space may include non-contiguous segments, held in a |
| list headed by an embedded malloc_segment record representing the |
| top-most space. Segments also include flags holding properties of |
| the space. Large chunks that are directly allocated by mmap are not |
| included in this list. They are instead independently created and |
| destroyed without otherwise keeping track of them. |
| |
| Segment management mainly comes into play for spaces allocated by |
| MMAP. Any call to MMAP might or might not return memory that is |
| adjacent to an existing segment. MORECORE normally contiguously |
| extends the current space, so this space is almost always adjacent, |
| which is simpler and faster to deal with. (This is why MORECORE is |
| used preferentially to MMAP when both are available -- see |
| sys_alloc.) When allocating using MMAP, we don't use any of the |
| hinting mechanisms (inconsistently) supported in various |
| implementations of unix mmap, or distinguish reserving from |
| committing memory. Instead, we just ask for space, and exploit |
| contiguity when we get it. It is probably possible to do |
| better than this on some systems, but no general scheme seems |
| to be significantly better. |
| |
| Management entails a simpler variant of the consolidation scheme |
| used for chunks to reduce fragmentation -- new adjacent memory is |
| normally prepended or appended to an existing segment. However, |
| there are limitations compared to chunk consolidation that mostly |
| reflect the fact that segment processing is relatively infrequent |
| (occurring only when getting memory from system) and that we |
| don't expect to have huge numbers of segments: |
| |
| * Segments are not indexed, so traversal requires linear scans. (It |
| would be possible to index these, but is not worth the extra |
| overhead and complexity for most programs on most platforms.) |
| * New segments are only appended to old ones when holding top-most |
| memory; if they cannot be prepended to others, they are held in |
| different segments. |
| |
| Except for the top-most segment of an mstate, each segment record |
| is kept at the tail of its segment. Segments are added by pushing |
| segment records onto the list headed by &mstate.seg for the |
| containing mstate. |
| |
| Segment flags control allocation/merge/deallocation policies: |
| * If EXTERN_BIT set, then we did not allocate this segment, |
| and so should not try to deallocate or merge with others. |
| (This currently holds only for the initial segment passed |
| into create_mspace_with_base.) |
| * If USE_MMAP_BIT set, the segment may be merged with |
| other surrounding mmapped segments and trimmed/de-allocated |
| using munmap. |
| * If neither bit is set, then the segment was obtained using |
| MORECORE so can be merged with surrounding MORECORE'd segments |
| and deallocated/trimmed using MORECORE with negative arguments. |
| */ |
| |
| struct malloc_segment { |
| char* base; /* base address */ |
| size_t size; /* allocated size */ |
| struct malloc_segment* next; /* ptr to next segment */ |
| flag_t sflags; /* mmap and extern flag */ |
| }; |
| |
| #define is_mmapped_segment(S) ((S)->sflags & USE_MMAP_BIT) |
| #define is_extern_segment(S) ((S)->sflags & EXTERN_BIT) |
| |
| typedef struct malloc_segment msegment; |
| typedef struct malloc_segment* msegmentptr; |
| |
| /* ---------------------------- malloc_state ----------------------------- */ |
| |
| /* |
| A malloc_state holds all of the bookkeeping for a space. |
| The main fields are: |
| |
| Top |
| The topmost chunk of the currently active segment. Its size is |
| cached in topsize. The actual size of topmost space is |
| topsize+TOP_FOOT_SIZE, which includes space reserved for adding |
| fenceposts and segment records if necessary when getting more |
| space from the system. The size at which to autotrim top is |
| cached from mparams in trim_check, except that it is disabled if |
| an autotrim fails. |
| |
| Designated victim (dv) |
| This is the preferred chunk for servicing small requests that |
| don't have exact fits. It is normally the chunk split off most |
| recently to service another small request. Its size is cached in |
| dvsize. The link fields of this chunk are not maintained since it |
| is not kept in a bin. |
| |
| SmallBins |
| An array of bin headers for free chunks. These bins hold chunks |
| with sizes less than MIN_LARGE_SIZE bytes. Each bin contains |
| chunks of all the same size, spaced 8 bytes apart. To simplify |
| use in double-linked lists, each bin header acts as a malloc_chunk |
| pointing to the real first node, if it exists (else pointing to |
| itself). This avoids special-casing for headers. But to avoid |
| waste, we allocate only the fd/bk pointers of bins, and then use |
| repositioning tricks to treat these as the fields of a chunk. |
| |
| TreeBins |
| Treebins are pointers to the roots of trees holding a range of |
| sizes. There are 2 equally spaced treebins for each power of two |
| from TREE_SHIFT to TREE_SHIFT+16. The last bin holds anything |
| larger. |
| |
| Bin maps |
| There is one bit map for small bins ("smallmap") and one for |
| treebins ("treemap). Each bin sets its bit when non-empty, and |
| clears the bit when empty. Bit operations are then used to avoid |
| bin-by-bin searching -- nearly all "search" is done without ever |
| looking at bins that won't be selected. The bit maps |
| conservatively use 32 bits per map word, even if on 64bit system. |
| For a good description of some of the bit-based techniques used |
| here, see Henry S. Warren Jr's book "Hacker's Delight" (and |
| supplement at http://hackersdelight.org/). Many of these are |
| intended to reduce the branchiness of paths through malloc etc, as |
| well as to reduce the number of memory locations read or written. |
| |
| Segments |
| A list of segments headed by an embedded malloc_segment record |
| representing the initial space. |
| |
| Address check support |
| The least_addr field is the least address ever obtained from |
| MORECORE or MMAP. Attempted frees and reallocs of any address less |
| than this are trapped (unless INSECURE is defined). |
| |
| Magic tag |
| A cross-check field that should always hold same value as mparams.magic. |
| |
| Max allowed footprint |
| The maximum allowed bytes to allocate from system (zero means no limit) |
| |
| Flags |
| Bits recording whether to use MMAP, locks, or contiguous MORECORE |
| |
| Statistics |
| Each space keeps track of current and maximum system memory |
| obtained via MORECORE or MMAP. |
| |
| Trim support |
| Fields holding the amount of unused topmost memory that should trigger |
| trimming, and a counter to force periodic scanning to release unused |
| non-topmost segments. |
| |
| Locking |
| If USE_LOCKS is defined, the "mutex" lock is acquired and released |
| around every public call using this mspace. |
| |
| Extension support |
| A void* pointer and a size_t field that can be used to help implement |
| extensions to this malloc. |
| */ |
| |
| /* Bin types, widths and sizes */ |
| #define NSMALLBINS (32U) |
| #define NTREEBINS (32U) |
| #define SMALLBIN_SHIFT (3U) |
| #define SMALLBIN_WIDTH (SIZE_T_ONE << SMALLBIN_SHIFT) |
| #define TREEBIN_SHIFT (8U) |
| #define MIN_LARGE_SIZE (SIZE_T_ONE << TREEBIN_SHIFT) |
| #define MAX_SMALL_SIZE (MIN_LARGE_SIZE - SIZE_T_ONE) |
| #define MAX_SMALL_REQUEST (MAX_SMALL_SIZE - CHUNK_ALIGN_MASK - CHUNK_OVERHEAD) |
| |
| struct malloc_state { |
| binmap_t smallmap; |
| binmap_t treemap; |
| size_t dvsize; |
| size_t topsize; |
| char* least_addr; |
| mchunkptr dv; |
| mchunkptr top; |
| size_t trim_check; |
| size_t release_checks; |
| size_t magic; |
| mchunkptr smallbins[(NSMALLBINS+1)*2]; |
| tbinptr treebins[NTREEBINS]; |
| size_t footprint; |
| size_t max_footprint; |
| size_t footprint_limit; /* zero means no limit */ |
| flag_t mflags; |
| #if USE_LOCKS |
| MLOCK_T mutex; /* locate lock among fields that rarely change */ |
| #endif /* USE_LOCKS */ |
| msegment seg; |
| void* extp; /* Unused but available for extensions */ |
| size_t exts; |
| size_t inuse; |
| }; |
| |
| typedef struct malloc_state* mstate; |
| |
| /* ------------- Global malloc_state and malloc_params ------------------- */ |
| |
| /* |
| malloc_params holds global properties, including those that can be |
| dynamically set using mallopt. There is a single instance, mparams, |
| initialized in init_mparams. Note that the non-zeroness of "magic" |
| also serves as an initialization flag. |
| */ |
| |
| struct malloc_params { |
| size_t magic; |
| size_t page_size; |
| size_t granularity; |
| size_t mmap_threshold; |
| size_t trim_threshold; |
| flag_t default_mflags; |
| }; |
| |
| static struct malloc_params mparams; |
| |
| /* Ensure mparams initialized */ |
| #define ensure_initialization() (void)(mparams.magic != 0 || init_mparams()) |
| |
| #if !ONLY_MSPACES |
| |
| /* The global malloc_state used for all non-"mspace" calls */ |
| static struct malloc_state _gm_; |
| #define gm (&_gm_) |
| #define is_global(M) ((M) == &_gm_) |
| |
| #endif /* !ONLY_MSPACES */ |
| |
| #define is_initialized(M) ((M)->top != 0) |
| |
| /* -------------------------- system alloc setup ------------------------- */ |
| |
| /* Operations on mflags */ |
| |
| #define use_lock(M) ((M)->mflags & USE_LOCK_BIT) |
| #define enable_lock(M) ((M)->mflags |= USE_LOCK_BIT) |
| #if USE_LOCKS |
| #define disable_lock(M) ((M)->mflags &= ~USE_LOCK_BIT) |
| #else |
| #define disable_lock(M) |
| #endif |
| |
| #define use_mmap(M) ((M)->mflags & USE_MMAP_BIT) |
| #define enable_mmap(M) ((M)->mflags |= USE_MMAP_BIT) |
| #if HAVE_MMAP |
| #define disable_mmap(M) ((M)->mflags &= ~USE_MMAP_BIT) |
| #else |
| #define disable_mmap(M) |
| #endif |
| |
| #define use_noncontiguous(M) ((M)->mflags & USE_NONCONTIGUOUS_BIT) |
| #define disable_contiguous(M) ((M)->mflags |= USE_NONCONTIGUOUS_BIT) |
| |
| #define set_lock(M,L)\ |
| ((M)->mflags = (L)?\ |
| ((M)->mflags | USE_LOCK_BIT) :\ |
| ((M)->mflags & ~USE_LOCK_BIT)) |
| |
| /* page-align a size */ |
| #define page_align(S)\ |
| (((S) + (mparams.page_size - SIZE_T_ONE)) & ~(mparams.page_size - SIZE_T_ONE)) |
| |
| /* granularity-align a size */ |
| #define granularity_align(S)\ |
| (((S) + (mparams.granularity - SIZE_T_ONE))\ |
| & ~(mparams.granularity - SIZE_T_ONE)) |
| |
| |
| /* For mmap, use granularity alignment on windows, else page-align */ |
| #ifdef WIN32 |
| #define mmap_align(S) granularity_align(S) |
| #else |
| #define mmap_align(S) page_align(S) |
| #endif |
| |
| /* For sys_alloc, enough padding to ensure can malloc request on success */ |
| #define SYS_ALLOC_PADDING (TOP_FOOT_SIZE + MALLOC_ALIGNMENT) |
| |
| #define is_page_aligned(S)\ |
| (((size_t)(S) & (mparams.page_size - SIZE_T_ONE)) == 0) |
| #define is_granularity_aligned(S)\ |
| (((size_t)(S) & (mparams.granularity - SIZE_T_ONE)) == 0) |
| |
| /* True if segment S holds address A */ |
| #define segment_holds(S, A)\ |
| ((char*)(A) >= S->base && (char*)(A) < S->base + S->size) |
| |
| /* Return segment holding given address */ |
| static msegmentptr segment_holding(mstate m, char* addr) { |
| msegmentptr sp = &m->seg; |
| for (;;) { |
| if (addr >= sp->base && addr < sp->base + sp->size) |
| return sp; |
| if ((sp = sp->next) == 0) |
| return 0; |
| } |
| } |
| |
| /* Return true if segment contains a segment link */ |
| static int has_segment_link(mstate m, msegmentptr ss) { |
| msegmentptr sp = &m->seg; |
| for (;;) { |
| if ((char*)sp >= ss->base && (char*)sp < ss->base + ss->size) |
| return 1; |
| if ((sp = sp->next) == 0) |
| return 0; |
| } |
| } |
| |
| #ifndef MORECORE_CANNOT_TRIM |
| #define should_trim(M,s) ((s) > (M)->trim_check) |
| #else /* MORECORE_CANNOT_TRIM */ |
| #define should_trim(M,s) (0) |
| #endif /* MORECORE_CANNOT_TRIM */ |
| |
| /* |
| TOP_FOOT_SIZE is padding at the end of a segment, including space |
| that may be needed to place segment records and fenceposts when new |
| noncontiguous segments are added. |
| */ |
| #define TOP_FOOT_SIZE\ |
| (align_offset(chunk2mem(0))+pad_request(sizeof(struct malloc_segment))+MIN_CHUNK_SIZE) |
| |
| |
| /* ------------------------------- Hooks -------------------------------- */ |
| |
| /* |
| PREACTION should be defined to return 0 on success, and nonzero on |
| failure. If you are not using locking, you can redefine these to do |
| anything you like. |
| */ |
| |
| #if USE_LOCKS |
| #define PREACTION(M) ((use_lock(M))? ACQUIRE_LOCK(&(M)->mutex) : 0) |
| #define POSTACTION(M) { if (use_lock(M)) RELEASE_LOCK(&(M)->mutex); } |
| #else /* USE_LOCKS */ |
| |
| #ifndef PREACTION |
| #define PREACTION(M) (0) |
| #endif /* PREACTION */ |
| |
| #ifndef POSTACTION |
| #define POSTACTION(M) |
| #endif /* POSTACTION */ |
| |
| #endif /* USE_LOCKS */ |
| |
| /* |
| CORRUPTION_ERROR_ACTION is triggered upon detected bad addresses. |
| USAGE_ERROR_ACTION is triggered on detected bad frees and |
| reallocs. The argument p is an address that might have triggered the |
| fault. It is ignored by the two predefined actions, but might be |
| useful in custom actions that try to help diagnose errors. |
| */ |
| |
| #if PROCEED_ON_ERROR |
| |
| /* A count of the number of corruption errors causing resets */ |
| int malloc_corruption_error_count; |
| |
| /* default corruption action */ |
| static void reset_on_error(mstate m); |
| |
| #define CORRUPTION_ERROR_ACTION(m) reset_on_error(m) |
| #define USAGE_ERROR_ACTION(m, p) |
| |
| #else /* PROCEED_ON_ERROR */ |
| |
| #ifndef CORRUPTION_ERROR_ACTION |
| #define CORRUPTION_ERROR_ACTION(m) ABORT |
| #endif /* CORRUPTION_ERROR_ACTION */ |
| |
| #ifndef USAGE_ERROR_ACTION |
| #define USAGE_ERROR_ACTION(m,p) ABORT |
| #endif /* USAGE_ERROR_ACTION */ |
| |
| #endif /* PROCEED_ON_ERROR */ |
| |
| |
| /* -------------------------- Debugging setup ---------------------------- */ |
| |
| #if ! DEBUG |
| |
| #define check_free_chunk(M,P) |
| #define check_inuse_chunk(M,P) |
| #define check_malloced_chunk(M,P,N) |
| #define check_mmapped_chunk(M,P) |
| #define check_malloc_state(M) |
| #define check_top_chunk(M,P) |
| |
| #else /* DEBUG */ |
| #define check_free_chunk(M,P) do_check_free_chunk(M,P) |
| #define check_inuse_chunk(M,P) do_check_inuse_chunk(M,P) |
| #define check_top_chunk(M,P) do_check_top_chunk(M,P) |
| #define check_malloced_chunk(M,P,N) do_check_malloced_chunk(M,P,N) |
| #define check_mmapped_chunk(M,P) do_check_mmapped_chunk(M,P) |
| #define check_malloc_state(M) do_check_malloc_state(M) |
| |
| static void do_check_any_chunk(mstate m, mchunkptr p); |
| static void do_check_top_chunk(mstate m, mchunkptr p); |
| static void do_check_mmapped_chunk(mstate m, mchunkptr p); |
| static void do_check_inuse_chunk(mstate m, mchunkptr p); |
| static void do_check_free_chunk(mstate m, mchunkptr p); |
| static void do_check_malloced_chunk(mstate m, void* mem, size_t s); |
| static void do_check_tree(mstate m, tchunkptr t); |
| static void do_check_treebin(mstate m, bindex_t i); |
| static void do_check_smallbin(mstate m, bindex_t i); |
| static void do_check_malloc_state(mstate m); |
| static int bin_find(mstate m, mchunkptr x); |
| static size_t traverse_and_check(mstate m); |
| #endif /* DEBUG */ |
| |
| /* ---------------------------- Indexing Bins ---------------------------- */ |
| |
| #define is_small(s) (((s) >> SMALLBIN_SHIFT) < NSMALLBINS) |
| #define small_index(s) (bindex_t)((s) >> SMALLBIN_SHIFT) |
| #define small_index2size(i) ((i) << SMALLBIN_SHIFT) |
| #define MIN_SMALL_INDEX (small_index(MIN_CHUNK_SIZE)) |
| |
| /* addressing by index. See above about smallbin repositioning */ |
| #define smallbin_at(M, i) ((sbinptr)((char*)&((M)->smallbins[(i)<<1]))) |
| #define treebin_at(M,i) (&((M)->treebins[i])) |
| |
| /* assign tree index for size S to variable I. Use x86 asm if possible */ |
| #if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)) |
| #define compute_tree_index(S, I)\ |
| {\ |
| unsigned int X = S >> TREEBIN_SHIFT;\ |
| if (X == 0)\ |
| I = 0;\ |
| else if (X > 0xFFFF)\ |
| I = NTREEBINS-1;\ |
| else {\ |
| unsigned int K = (unsigned) sizeof(X)*__CHAR_BIT__ - 1 - (unsigned) __builtin_clz(X); \ |
| I = (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\ |
| }\ |
| } |
| |
| #elif defined (__INTEL_COMPILER) |
| #define compute_tree_index(S, I)\ |
| {\ |
| size_t X = S >> TREEBIN_SHIFT;\ |
| if (X == 0)\ |
| I = 0;\ |
| else if (X > 0xFFFF)\ |
| I = NTREEBINS-1;\ |
| else {\ |
| unsigned int K = _bit_scan_reverse (X); \ |
| I = (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\ |
| }\ |
| } |
| |
| #elif defined(_MSC_VER) && _MSC_VER>=1300 && !defined(__LB_XB360__) |
| #define compute_tree_index(S, I)\ |
| {\ |
| size_t X = S >> TREEBIN_SHIFT;\ |
| if (X == 0)\ |
| I = 0;\ |
| else if (X > 0xFFFF)\ |
| I = NTREEBINS-1;\ |
| else {\ |
| unsigned int K;\ |
| _BitScanReverse((DWORD *) &K, (DWORD) X);\ |
| I = (bindex_t)((K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1)));\ |
| }\ |
| } |
| |
| #else /* GNUC */ |
| #define compute_tree_index(S, I)\ |
| {\ |
| size_t X = S >> TREEBIN_SHIFT;\ |
| if (X == 0)\ |
| I = 0;\ |
| else if (X > 0xFFFF)\ |
| I = NTREEBINS-1;\ |
| else {\ |
| unsigned int Y = (unsigned int)X;\ |
| unsigned int N = ((Y - 0x100) >> 16) & 8;\ |
| unsigned int K = (((Y <<= N) - 0x1000) >> 16) & 4;\ |
| N += K;\ |
| N += K = (((Y <<= K) - 0x4000) >> 16) & 2;\ |
| K = 14 - N + ((Y <<= K) >> 15);\ |
| I = (K << 1) + ((S >> (K + (TREEBIN_SHIFT-1)) & 1));\ |
| }\ |
| } |
| #endif /* GNUC */ |
| |
| /* Bit representing maximum resolved size in a treebin at i */ |
| #define bit_for_tree_index(i) \ |
| (i == NTREEBINS-1)? (SIZE_T_BITSIZE-1) : (((i) >> 1) + TREEBIN_SHIFT - 2) |
| |
| /* Shift placing maximum resolved bit in a treebin at i as sign bit */ |
| #define leftshift_for_tree_index(i) \ |
| ((i == NTREEBINS-1)? 0 : \ |
| ((SIZE_T_BITSIZE-SIZE_T_ONE) - (((i) >> 1) + TREEBIN_SHIFT - 2))) |
| |
| /* The size of the smallest chunk held in bin with index i */ |
| #define minsize_for_tree_index(i) \ |
| ((SIZE_T_ONE << (((i) >> 1) + TREEBIN_SHIFT)) | \ |
| (((size_t)((i) & SIZE_T_ONE)) << (((i) >> 1) + TREEBIN_SHIFT - 1))) |
| |
| |
| /* ------------------------ Operations on bin maps ----------------------- */ |
| |
| /* bit corresponding to given index */ |
| #define idx2bit(i) ((binmap_t)(1) << (i)) |
| |
| /* Mark/Clear bits with given index */ |
| #define mark_smallmap(M,i) ((M)->smallmap |= idx2bit(i)) |
| #define clear_smallmap(M,i) ((M)->smallmap &= ~idx2bit(i)) |
| #define smallmap_is_marked(M,i) ((M)->smallmap & idx2bit(i)) |
| |
| #define mark_treemap(M,i) ((M)->treemap |= idx2bit(i)) |
| #define clear_treemap(M,i) ((M)->treemap &= ~idx2bit(i)) |
| #define treemap_is_marked(M,i) ((M)->treemap & idx2bit(i)) |
| |
| /* isolate the least set bit of a bitmap */ |
| #define least_bit(x) ((x) & -(x)) |
| |
| /* mask with all bits to left of least bit of x on */ |
| #define left_bits(x) ((x<<1) | -(x<<1)) |
| |
| /* mask with all bits to left of or equal to least bit of x on */ |
| #define same_or_left_bits(x) ((x) | -(x)) |
| |
| /* index corresponding to given bit. Use x86 asm if possible */ |
| |
| #if defined(__GNUC__) && (defined(__i386__) || defined(__x86_64__)) |
| #define compute_bit2idx(X, I)\ |
| {\ |
| unsigned int J;\ |
| J = __builtin_ctz(X); \ |
| I = (bindex_t)J;\ |
| } |
| |
| #elif defined (__INTEL_COMPILER) |
| #define compute_bit2idx(X, I)\ |
| {\ |
| unsigned int J;\ |
| J = _bit_scan_forward (X); \ |
| I = (bindex_t)J;\ |
| } |
| |
| #elif defined(_MSC_VER) && _MSC_VER>=1300 && !defined(__LB_XB360__) |
| #define compute_bit2idx(X, I)\ |
| {\ |
| unsigned int J;\ |
| _BitScanForward((DWORD *) &J, X);\ |
| I = (bindex_t)J;\ |
| } |
| |
| #elif USE_BUILTIN_FFS |
| #define compute_bit2idx(X, I) I = ffs(X)-1 |
| |
| #else |
| #define compute_bit2idx(X, I)\ |
| {\ |
| unsigned int Y = X - 1;\ |
| unsigned int K = Y >> (16-4) & 16;\ |
| unsigned int N = K; Y >>= K;\ |
| N += K = Y >> (8-3) & 8; Y >>= K;\ |
| N += K = Y >> (4-2) & 4; Y >>= K;\ |
| N += K = Y >> (2-1) & 2; Y >>= K;\ |
| N += K = Y >> (1-0) & 1; Y >>= K;\ |
| I = (bindex_t)(N + Y);\ |
| } |
| #endif /* GNUC */ |
| |
| |
| /* ----------------------- Runtime Check Support ------------------------- */ |
| |
| /* |
| For security, the main invariant is that malloc/free/etc never |
| writes to a static address other than malloc_state, unless static |
| malloc_state itself has been corrupted, which cannot occur via |
| malloc (because of these checks). In essence this means that we |
| believe all pointers, sizes, maps etc held in malloc_state, but |
| check all of those linked or offsetted from other embedded data |
| structures. These checks are interspersed with main code in a way |
| that tends to minimize their run-time cost. |
| |
| When FOOTERS is defined, in addition to range checking, we also |
| verify footer fields of inuse chunks, which can be used guarantee |
| that the mstate controlling malloc/free is intact. This is a |
| streamlined version of the approach described by William Robertson |
| et al in "Run-time Detection of Heap-based Overflows" LISA'03 |
| http://www.usenix.org/events/lisa03/tech/robertson.html The footer |
| of an inuse chunk holds the xor of its mstate and a random seed, |
| that is checked upon calls to free() and realloc(). This is |
| (probabalistically) unguessable from outside the program, but can be |
| computed by any code successfully malloc'ing any chunk, so does not |
| itself provide protection against code that has already broken |
| security through some other means. Unlike Robertson et al, we |
| always dynamically check addresses of all offset chunks (previous, |
| next, etc). This turns out to be cheaper than relying on hashes. |
| */ |
| |
| #if !INSECURE |
| /* Check if address a is at least as high as any from MORECORE or MMAP */ |
| #define ok_address(M, a) ((char*)(a) >= (M)->least_addr) |
| /* Check if address of next chunk n is higher than base chunk p */ |
| #define ok_next(p, n) ((char*)(p) < (char*)(n)) |
| /* Check if p has inuse status */ |
| #define ok_inuse(p) is_inuse(p) |
| /* Check if p has its pinuse bit on */ |
| #define ok_pinuse(p) pinuse(p) |
| |
| #else /* !INSECURE */ |
| #define ok_address(M, a) (1) |
| #define ok_next(b, n) (1) |
| #define ok_inuse(p) (1) |
| #define ok_pinuse(p) (1) |
| #endif /* !INSECURE */ |
| |
| #if (FOOTERS && !INSECURE) |
| /* Check if (alleged) mstate m has expected magic field */ |
| #define ok_magic(M) ((M)->magic == mparams.magic) |
| #else /* (FOOTERS && !INSECURE) */ |
| #define ok_magic(M) (1) |
| #endif /* (FOOTERS && !INSECURE) */ |
| |
| /* In gcc, use __builtin_expect to minimize impact of checks */ |
| #if !INSECURE |
| #if defined(__GNUC__) && __GNUC__ >= 3 |
| #define RTCHECK(e) __builtin_expect(e, 1) |
| #else /* GNUC */ |
| #define RTCHECK(e) (e) |
| #endif /* GNUC */ |
| #else /* !INSECURE */ |
| #define RTCHECK(e) (1) |
| #endif /* !INSECURE */ |
| |
| /* macros to set up inuse chunks with or without footers */ |
| |
| #if !FOOTERS |
| |
| #define mark_inuse_foot(M,p,s) |
| |
| /* Macros for setting head/foot of non-mmapped chunks */ |
| |
| /* Set cinuse bit and pinuse bit of next chunk */ |
| #define set_inuse(M,p,s)\ |
| ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\ |
| ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT) |
| |
| /* Set cinuse and pinuse of this chunk and pinuse of next chunk */ |
| #define set_inuse_and_pinuse(M,p,s)\ |
| ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\ |
| ((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT) |
| |
| /* Set size, cinuse and pinuse bit of this chunk */ |
| #define set_size_and_pinuse_of_inuse_chunk(M, p, s)\ |
| ((p)->head = (s|PINUSE_BIT|CINUSE_BIT)) |
| |
| #else /* FOOTERS */ |
| |
| /* Set foot of inuse chunk to be xor of mstate and seed */ |
| #define mark_inuse_foot(M,p,s)\ |
| (((mchunkptr)((char*)(p) + (s)))->prev_foot = ((size_t)(M) ^ mparams.magic)) |
| |
| #define get_mstate_for(p)\ |
| ((mstate)(((mchunkptr)((char*)(p) +\ |
| (chunksize(p))))->prev_foot ^ mparams.magic)) |
| |
| #define set_inuse(M,p,s)\ |
| ((p)->head = (((p)->head & PINUSE_BIT)|s|CINUSE_BIT),\ |
| (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT), \ |
| mark_inuse_foot(M,p,s)) |
| |
| #define set_inuse_and_pinuse(M,p,s)\ |
| ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\ |
| (((mchunkptr)(((char*)(p)) + (s)))->head |= PINUSE_BIT),\ |
| mark_inuse_foot(M,p,s)) |
| |
| #define set_size_and_pinuse_of_inuse_chunk(M, p, s)\ |
| ((p)->head = (s|PINUSE_BIT|CINUSE_BIT),\ |
| mark_inuse_foot(M, p, s)) |
| |
| #endif /* !FOOTERS */ |
| |
| /* ---------------------------- setting mparams -------------------------- */ |
| |
| #if LOCK_AT_FORK |
| static void pre_fork(void) { ACQUIRE_LOCK(&(gm)->mutex); } |
| static void post_fork_parent(void) { RELEASE_LOCK(&(gm)->mutex); } |
| static void post_fork_child(void) { INITIAL_LOCK(&(gm)->mutex); } |
| #endif /* LOCK_AT_FORK */ |
| |
| #if defined(__LB_SHELL__) || defined(STARBOARD) |
| static void dl_heap_init(); |
| #endif |
| |
| /* Initialize mparams */ |
| static int init_mparams(void) { |
| #ifdef NEED_GLOBAL_LOCK_INIT |
| if (malloc_global_mutex_status <= 0) |
| init_malloc_global_mutex(); |
| #endif |
| |
| ACQUIRE_MALLOC_GLOBAL_LOCK(); |
| if (mparams.magic == 0) { |
| size_t magic; |
| size_t psize; |
| size_t gsize; |
| |
| #ifndef WIN32 |
| psize = malloc_getpagesize; |
| gsize = ((DEFAULT_GRANULARITY != 0)? DEFAULT_GRANULARITY : psize); |
| #else /* WIN32 */ |
| { |
| SYSTEM_INFO system_info; |
| GetSystemInfo(&system_info); |
| psize = system_info.dwPageSize; |
| gsize = ((DEFAULT_GRANULARITY != 0)? |
| DEFAULT_GRANULARITY : system_info.dwAllocationGranularity); |
| } |
| #endif /* WIN32 */ |
| |
| /* Sanity-check configuration: |
| size_t must be unsigned and as wide as pointer type. |
| ints must be at least 4 bytes. |
| alignment must be at least 8. |
| Alignment, min chunk size, and page size must all be powers of 2. |
| */ |
| if ((sizeof(size_t) != sizeof(char*)) || |
| (MAX_SIZE_T < MIN_CHUNK_SIZE) || |
| (sizeof(int) < 4) || |
| (MALLOC_ALIGNMENT < (size_t)8U) || |
| ((MALLOC_ALIGNMENT & (MALLOC_ALIGNMENT-SIZE_T_ONE)) != 0) || |
| ((MCHUNK_SIZE & (MCHUNK_SIZE-SIZE_T_ONE)) != 0) || |
| ((gsize & (gsize-SIZE_T_ONE)) != 0) || |
| ((psize & (psize-SIZE_T_ONE)) != 0)) |
| ABORT; |
| mparams.granularity = gsize; |
| mparams.page_size = psize; |
| mparams.mmap_threshold = DEFAULT_MMAP_THRESHOLD; |
| mparams.trim_threshold = DEFAULT_TRIM_THRESHOLD; |
| #if MORECORE_CONTIGUOUS |
| mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT; |
| #else /* MORECORE_CONTIGUOUS */ |
| mparams.default_mflags = USE_LOCK_BIT|USE_MMAP_BIT|USE_NONCONTIGUOUS_BIT; |
| #endif /* MORECORE_CONTIGUOUS */ |
| |
| #if !ONLY_MSPACES |
| /* Set up lock for main malloc area */ |
| gm->mflags = mparams.default_mflags; |
| (void)INITIAL_LOCK(&gm->mutex); |
| #endif |
| #if LOCK_AT_FORK |
| pthread_atfork(&pre_fork, &post_fork_parent, &post_fork_child); |
| #endif |
| |
| { |
| #if USE_DEV_RANDOM |
| int fd; |
| unsigned char buf[sizeof(size_t)]; |
| /* Try to use /dev/urandom, else fall back on using time */ |
| if ((fd = open("/dev/urandom", O_RDONLY)) >= 0 && |
| read(fd, buf, sizeof(buf)) == sizeof(buf)) { |
| magic = *((size_t *) buf); |
| close(fd); |
| } |
| else |
| #endif /* USE_DEV_RANDOM */ |
| #ifdef WIN32 |
| magic = (size_t)(GetTickCount() ^ (size_t)0x55555555U); |
| #elif defined(LACKS_TIME_H) |
| magic = (size_t)&magic ^ (size_t)0x55555555U; |
| #else |
| magic = (size_t)(time(0) ^ (size_t)0x55555555U); |
| #endif |
| magic |= (size_t)8U; /* ensure nonzero */ |
| magic &= ~(size_t)7U; /* improve chances of fault for bad values */ |
| /* Until memory modes commonly available, use volatile-write */ |
| (*(volatile size_t *)(&(mparams.magic))) = magic; |
| } |
| #if defined(__LB_SHELL__) || defined(STARBOARD) |
| // Call our own initialization functions. |
| dl_heap_init(); |
| #endif |
| } |
| RELEASE_MALLOC_GLOBAL_LOCK(); |
| return 1; |
| } |
| |
| /* support for mallopt */ |
| static int change_mparam(int param_number, int value) { |
| size_t val; |
| ensure_initialization(); |
| val = (value == -1)? MAX_SIZE_T : (size_t)value; |
| switch(param_number) { |
| case M_TRIM_THRESHOLD: |
| mparams.trim_threshold = val; |
| return 1; |
| case M_GRANULARITY: |
| if (val >= mparams.page_size && ((val & (val-1)) == 0)) { |
| mparams.granularity = val; |
| return 1; |
| } |
| else |
| return 0; |
| case M_MMAP_THRESHOLD: |
| mparams.mmap_threshold = val; |
| return 1; |
| default: |
| return 0; |
| } |
| } |
| |
| #if DEBUG |
| /* ------------------------- Debugging Support --------------------------- */ |
| |
| /* Check properties of any chunk, whether free, inuse, mmapped etc */ |
| static void do_check_any_chunk(mstate m, mchunkptr p) { |
| assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD)); |
| assert(ok_address(m, p)); |
| } |
| |
| /* Check properties of top chunk */ |
| static void do_check_top_chunk(mstate m, mchunkptr p) { |
| msegmentptr sp = segment_holding(m, (char*)p); |
| size_t sz = p->head & ~INUSE_BITS; /* third-lowest bit can be set! */ |
| assert(sp != 0); |
| assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD)); |
| assert(ok_address(m, p)); |
| assert(sz == m->topsize); |
| assert(sz > 0); |
| assert(sz == ((sp->base + sp->size) - (char*)p) - TOP_FOOT_SIZE); |
| assert(pinuse(p)); |
| assert(!pinuse(chunk_plus_offset(p, sz))); |
| } |
| |
| /* Check properties of (inuse) mmapped chunks */ |
| static void do_check_mmapped_chunk(mstate m, mchunkptr p) { |
| size_t sz = chunksize(p); |
| size_t len = (sz + (p->prev_foot) + MMAP_FOOT_PAD); |
| assert(is_mmapped(p)); |
| assert(use_mmap(m)); |
| assert((is_aligned(chunk2mem(p))) || (p->head == FENCEPOST_HEAD)); |
| assert(ok_address(m, p)); |
| assert(!is_small(sz)); |
| assert((len & (mparams.page_size-SIZE_T_ONE)) == 0); |
| assert(chunk_plus_offset(p, sz)->head == FENCEPOST_HEAD); |
| assert(chunk_plus_offset(p, sz+SIZE_T_SIZE)->head == 0); |
| } |
| |
| /* Check properties of inuse chunks */ |
| static void do_check_inuse_chunk(mstate m, mchunkptr p) { |
| do_check_any_chunk(m, p); |
| assert(is_inuse(p)); |
| assert(next_pinuse(p)); |
| /* If not pinuse and not mmapped, previous chunk has OK offset */ |
| assert(is_mmapped(p) || pinuse(p) || next_chunk(prev_chunk(p)) == p); |
| if (is_mmapped(p)) |
| do_check_mmapped_chunk(m, p); |
| } |
| |
| /* Check properties of free chunks */ |
| static void do_check_free_chunk(mstate m, mchunkptr p) { |
| size_t sz = chunksize(p); |
| mchunkptr next = chunk_plus_offset(p, sz); |
| do_check_any_chunk(m, p); |
| assert(!is_inuse(p)); |
| assert(!next_pinuse(p)); |
| assert (!is_mmapped(p)); |
| if (p != m->dv && p != m->top) { |
| if (sz >= MIN_CHUNK_SIZE) { |
| assert((sz & CHUNK_ALIGN_MASK) == 0); |
| assert(is_aligned(chunk2mem(p))); |
| assert(next->prev_foot == sz); |
| assert(pinuse(p)); |
| assert (next == m->top || is_inuse(next)); |
| assert(p->fd->bk == p); |
| assert(p->bk->fd == p); |
| } |
| else /* markers are always of size SIZE_T_SIZE */ |
| assert(sz == SIZE_T_SIZE); |
| } |
| } |
| |
| /* Check properties of malloced chunks at the point they are malloced */ |
| static void do_check_malloced_chunk(mstate m, void* mem, size_t s) { |
| if (mem != 0) { |
| mchunkptr p = mem2chunk(mem); |
| size_t sz = p->head & ~INUSE_BITS; |
| do_check_inuse_chunk(m, p); |
| assert((sz & CHUNK_ALIGN_MASK) == 0); |
| assert(sz >= MIN_CHUNK_SIZE); |
| assert(sz >= s); |
| /* unless mmapped, size is less than MIN_CHUNK_SIZE more than request */ |
| assert(is_mmapped(p) || sz < (s + MIN_CHUNK_SIZE)); |
| } |
| } |
| |
| /* Check a tree and its subtrees. */ |
| static void do_check_tree(mstate m, tchunkptr t) { |
| tchunkptr head = 0; |
| tchunkptr u = t; |
| bindex_t tindex = t->index; |
| size_t tsize = chunksize(t); |
| bindex_t idx; |
| compute_tree_index(tsize, idx); |
| assert(tindex == idx); |
| assert(tsize >= MIN_LARGE_SIZE); |
| assert(tsize >= minsize_for_tree_index(idx)); |
| assert((idx == NTREEBINS-1) || (tsize < minsize_for_tree_index((idx+1)))); |
| |
| do { /* traverse through chain of same-sized nodes */ |
| do_check_any_chunk(m, ((mchunkptr)u)); |
| assert(u->index == tindex); |
| assert(chunksize(u) == tsize); |
| assert(!is_inuse(u)); |
| assert(!next_pinuse(u)); |
| assert(u->fd->bk == u); |