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Diffstat (limited to 'AppPkg/Applications/Python/Python-2.7.10/Objects/obmalloc.c')
| -rw-r--r-- | AppPkg/Applications/Python/Python-2.7.10/Objects/obmalloc.c | 1937 |
1 files changed, 1937 insertions, 0 deletions
diff --git a/AppPkg/Applications/Python/Python-2.7.10/Objects/obmalloc.c b/AppPkg/Applications/Python/Python-2.7.10/Objects/obmalloc.c new file mode 100644 index 0000000000..2e83c3e1ad --- /dev/null +++ b/AppPkg/Applications/Python/Python-2.7.10/Objects/obmalloc.c @@ -0,0 +1,1937 @@ +#include "Python.h"
+
+#if defined(__has_feature) /* Clang */
+ #if __has_feature(address_sanitizer) /* is ASAN enabled? */
+ #define ATTRIBUTE_NO_ADDRESS_SAFETY_ANALYSIS \
+ __attribute__((no_address_safety_analysis)) \
+ __attribute__ ((noinline))
+ #else
+ #define ATTRIBUTE_NO_ADDRESS_SAFETY_ANALYSIS
+ #endif
+#else
+ #if defined(__SANITIZE_ADDRESS__) /* GCC 4.8.x, is ASAN enabled? */
+ #define ATTRIBUTE_NO_ADDRESS_SAFETY_ANALYSIS \
+ __attribute__((no_address_safety_analysis)) \
+ __attribute__ ((noinline))
+ #else
+ #define ATTRIBUTE_NO_ADDRESS_SAFETY_ANALYSIS
+ #endif
+#endif
+
+#ifdef WITH_PYMALLOC
+
+#ifdef HAVE_MMAP
+ #include <sys/mman.h>
+ #ifdef MAP_ANONYMOUS
+ #define ARENAS_USE_MMAP
+ #endif
+#endif
+
+#ifdef WITH_VALGRIND
+#include <valgrind/valgrind.h>
+
+/* If we're using GCC, use __builtin_expect() to reduce overhead of
+ the valgrind checks */
+#if defined(__GNUC__) && (__GNUC__ > 2) && defined(__OPTIMIZE__)
+# define UNLIKELY(value) __builtin_expect((value), 0)
+#else
+# define UNLIKELY(value) (value)
+#endif
+
+/* -1 indicates that we haven't checked that we're running on valgrind yet. */
+static int running_on_valgrind = -1;
+#endif
+
+/* An object allocator for Python.
+
+ Here is an introduction to the layers of the Python memory architecture,
+ showing where the object allocator is actually used (layer +2), It is
+ called for every object allocation and deallocation (PyObject_New/Del),
+ unless the object-specific allocators implement a proprietary allocation
+ scheme (ex.: ints use a simple free list). This is also the place where
+ the cyclic garbage collector operates selectively on container objects.
+
+
+ Object-specific allocators
+ _____ ______ ______ ________
+ [ int ] [ dict ] [ list ] ... [ string ] Python core |
++3 | <----- Object-specific memory -----> | <-- Non-object memory --> |
+ _______________________________ | |
+ [ Python's object allocator ] | |
++2 | ####### Object memory ####### | <------ Internal buffers ------> |
+ ______________________________________________________________ |
+ [ Python's raw memory allocator (PyMem_ API) ] |
++1 | <----- Python memory (under PyMem manager's control) ------> | |
+ __________________________________________________________________
+ [ Underlying general-purpose allocator (ex: C library malloc) ]
+ 0 | <------ Virtual memory allocated for the python process -------> |
+
+ =========================================================================
+ _______________________________________________________________________
+ [ OS-specific Virtual Memory Manager (VMM) ]
+-1 | <--- Kernel dynamic storage allocation & management (page-based) ---> |
+ __________________________________ __________________________________
+ [ ] [ ]
+-2 | <-- Physical memory: ROM/RAM --> | | <-- Secondary storage (swap) --> |
+
+*/
+/*==========================================================================*/
+
+/* A fast, special-purpose memory allocator for small blocks, to be used
+ on top of a general-purpose malloc -- heavily based on previous art. */
+
+/* Vladimir Marangozov -- August 2000 */
+
+/*
+ * "Memory management is where the rubber meets the road -- if we do the wrong
+ * thing at any level, the results will not be good. And if we don't make the
+ * levels work well together, we are in serious trouble." (1)
+ *
+ * (1) Paul R. Wilson, Mark S. Johnstone, Michael Neely, and David Boles,
+ * "Dynamic Storage Allocation: A Survey and Critical Review",
+ * in Proc. 1995 Int'l. Workshop on Memory Management, September 1995.
+ */
+
+/* #undef WITH_MEMORY_LIMITS */ /* disable mem limit checks */
+
+/*==========================================================================*/
+
+/*
+ * Allocation strategy abstract:
+ *
+ * For small requests, the allocator sub-allocates <Big> blocks of memory.
+ * Requests greater than SMALL_REQUEST_THRESHOLD bytes are routed to the
+ * system's allocator.
+ *
+ * Small requests are grouped in size classes spaced 8 bytes apart, due
+ * to the required valid alignment of the returned address. Requests of
+ * a particular size are serviced from memory pools of 4K (one VMM page).
+ * Pools are fragmented on demand and contain free lists of blocks of one
+ * particular size class. In other words, there is a fixed-size allocator
+ * for each size class. Free pools are shared by the different allocators
+ * thus minimizing the space reserved for a particular size class.
+ *
+ * This allocation strategy is a variant of what is known as "simple
+ * segregated storage based on array of free lists". The main drawback of
+ * simple segregated storage is that we might end up with lot of reserved
+ * memory for the different free lists, which degenerate in time. To avoid
+ * this, we partition each free list in pools and we share dynamically the
+ * reserved space between all free lists. This technique is quite efficient
+ * for memory intensive programs which allocate mainly small-sized blocks.
+ *
+ * For small requests we have the following table:
+ *
+ * Request in bytes Size of allocated block Size class idx
+ * ----------------------------------------------------------------
+ * 1-8 8 0
+ * 9-16 16 1
+ * 17-24 24 2
+ * 25-32 32 3
+ * 33-40 40 4
+ * 41-48 48 5
+ * 49-56 56 6
+ * 57-64 64 7
+ * 65-72 72 8
+ * ... ... ...
+ * 497-504 504 62
+ * 505-512 512 63
+ *
+ * 0, SMALL_REQUEST_THRESHOLD + 1 and up: routed to the underlying
+ * allocator.
+ */
+
+/*==========================================================================*/
+
+/*
+ * -- Main tunable settings section --
+ */
+
+/*
+ * Alignment of addresses returned to the user. 8-bytes alignment works
+ * on most current architectures (with 32-bit or 64-bit address busses).
+ * The alignment value is also used for grouping small requests in size
+ * classes spaced ALIGNMENT bytes apart.
+ *
+ * You shouldn't change this unless you know what you are doing.
+ */
+#define ALIGNMENT 8 /* must be 2^N */
+#define ALIGNMENT_SHIFT 3
+#define ALIGNMENT_MASK (ALIGNMENT - 1)
+
+/* Return the number of bytes in size class I, as a uint. */
+#define INDEX2SIZE(I) (((uint)(I) + 1) << ALIGNMENT_SHIFT)
+
+/*
+ * Max size threshold below which malloc requests are considered to be
+ * small enough in order to use preallocated memory pools. You can tune
+ * this value according to your application behaviour and memory needs.
+ *
+ * The following invariants must hold:
+ * 1) ALIGNMENT <= SMALL_REQUEST_THRESHOLD <= 256
+ * 2) SMALL_REQUEST_THRESHOLD is evenly divisible by ALIGNMENT
+ *
+ * Note: a size threshold of 512 guarantees that newly created dictionaries
+ * will be allocated from preallocated memory pools on 64-bit.
+ *
+ * Although not required, for better performance and space efficiency,
+ * it is recommended that SMALL_REQUEST_THRESHOLD is set to a power of 2.
+ */
+#define SMALL_REQUEST_THRESHOLD 512
+#define NB_SMALL_SIZE_CLASSES (SMALL_REQUEST_THRESHOLD / ALIGNMENT)
+
+/*
+ * The system's VMM page size can be obtained on most unices with a
+ * getpagesize() call or deduced from various header files. To make
+ * things simpler, we assume that it is 4K, which is OK for most systems.
+ * It is probably better if this is the native page size, but it doesn't
+ * have to be. In theory, if SYSTEM_PAGE_SIZE is larger than the native page
+ * size, then `POOL_ADDR(p)->arenaindex' could rarely cause a segmentation
+ * violation fault. 4K is apparently OK for all the platforms that python
+ * currently targets.
+ */
+#define SYSTEM_PAGE_SIZE (4 * 1024)
+#define SYSTEM_PAGE_SIZE_MASK (SYSTEM_PAGE_SIZE - 1)
+
+/*
+ * Maximum amount of memory managed by the allocator for small requests.
+ */
+#ifdef WITH_MEMORY_LIMITS
+#ifndef SMALL_MEMORY_LIMIT
+#define SMALL_MEMORY_LIMIT (64 * 1024 * 1024) /* 64 MB -- more? */
+#endif
+#endif
+
+/*
+ * The allocator sub-allocates <Big> blocks of memory (called arenas) aligned
+ * on a page boundary. This is a reserved virtual address space for the
+ * current process (obtained through a malloc()/mmap() call). In no way this
+ * means that the memory arenas will be used entirely. A malloc(<Big>) is
+ * usually an address range reservation for <Big> bytes, unless all pages within
+ * this space are referenced subsequently. So malloc'ing big blocks and not
+ * using them does not mean "wasting memory". It's an addressable range
+ * wastage...
+ *
+ * Arenas are allocated with mmap() on systems supporting anonymous memory
+ * mappings to reduce heap fragmentation.
+ */
+#define ARENA_SIZE (256 << 10) /* 256KB */
+
+#ifdef WITH_MEMORY_LIMITS
+#define MAX_ARENAS (SMALL_MEMORY_LIMIT / ARENA_SIZE)
+#endif
+
+/*
+ * Size of the pools used for small blocks. Should be a power of 2,
+ * between 1K and SYSTEM_PAGE_SIZE, that is: 1k, 2k, 4k.
+ */
+#define POOL_SIZE SYSTEM_PAGE_SIZE /* must be 2^N */
+#define POOL_SIZE_MASK SYSTEM_PAGE_SIZE_MASK
+
+/*
+ * -- End of tunable settings section --
+ */
+
+/*==========================================================================*/
+
+/*
+ * Locking
+ *
+ * To reduce lock contention, it would probably be better to refine the
+ * crude function locking with per size class locking. I'm not positive
+ * however, whether it's worth switching to such locking policy because
+ * of the performance penalty it might introduce.
+ *
+ * The following macros describe the simplest (should also be the fastest)
+ * lock object on a particular platform and the init/fini/lock/unlock
+ * operations on it. The locks defined here are not expected to be recursive
+ * because it is assumed that they will always be called in the order:
+ * INIT, [LOCK, UNLOCK]*, FINI.
+ */
+
+/*
+ * Python's threads are serialized, so object malloc locking is disabled.
+ */
+#define SIMPLELOCK_DECL(lock) /* simple lock declaration */
+#define SIMPLELOCK_INIT(lock) /* allocate (if needed) and initialize */
+#define SIMPLELOCK_FINI(lock) /* free/destroy an existing lock */
+#define SIMPLELOCK_LOCK(lock) /* acquire released lock */
+#define SIMPLELOCK_UNLOCK(lock) /* release acquired lock */
+
+/*
+ * Basic types
+ * I don't care if these are defined in <sys/types.h> or elsewhere. Axiom.
+ */
+#undef uchar
+#define uchar unsigned char /* assuming == 8 bits */
+
+#undef uint
+#define uint unsigned int /* assuming >= 16 bits */
+
+#undef ulong
+#define ulong unsigned long /* assuming >= 32 bits */
+
+#undef uptr
+#define uptr Py_uintptr_t
+
+/* When you say memory, my mind reasons in terms of (pointers to) blocks */
+typedef uchar block;
+
+/* Pool for small blocks. */
+struct pool_header {
+ union { block *_padding;
+ uint count; } ref; /* number of allocated blocks */
+ block *freeblock; /* pool's free list head */
+ struct pool_header *nextpool; /* next pool of this size class */
+ struct pool_header *prevpool; /* previous pool "" */
+ uint arenaindex; /* index into arenas of base adr */
+ uint szidx; /* block size class index */
+ uint nextoffset; /* bytes to virgin block */
+ uint maxnextoffset; /* largest valid nextoffset */
+};
+
+typedef struct pool_header *poolp;
+
+/* Record keeping for arenas. */
+struct arena_object {
+ /* The address of the arena, as returned by malloc. Note that 0
+ * will never be returned by a successful malloc, and is used
+ * here to mark an arena_object that doesn't correspond to an
+ * allocated arena.
+ */
+ uptr address;
+
+ /* Pool-aligned pointer to the next pool to be carved off. */
+ block* pool_address;
+
+ /* The number of available pools in the arena: free pools + never-
+ * allocated pools.
+ */
+ uint nfreepools;
+
+ /* The total number of pools in the arena, whether or not available. */
+ uint ntotalpools;
+
+ /* Singly-linked list of available pools. */
+ struct pool_header* freepools;
+
+ /* Whenever this arena_object is not associated with an allocated
+ * arena, the nextarena member is used to link all unassociated
+ * arena_objects in the singly-linked `unused_arena_objects` list.
+ * The prevarena member is unused in this case.
+ *
+ * When this arena_object is associated with an allocated arena
+ * with at least one available pool, both members are used in the
+ * doubly-linked `usable_arenas` list, which is maintained in
+ * increasing order of `nfreepools` values.
+ *
+ * Else this arena_object is associated with an allocated arena
+ * all of whose pools are in use. `nextarena` and `prevarena`
+ * are both meaningless in this case.
+ */
+ struct arena_object* nextarena;
+ struct arena_object* prevarena;
+};
+
+#undef ROUNDUP
+#define ROUNDUP(x) (((x) + ALIGNMENT_MASK) & ~ALIGNMENT_MASK)
+#define POOL_OVERHEAD ROUNDUP(sizeof(struct pool_header))
+
+#define DUMMY_SIZE_IDX 0xffff /* size class of newly cached pools */
+
+/* Round pointer P down to the closest pool-aligned address <= P, as a poolp */
+#define POOL_ADDR(P) ((poolp)((uptr)(P) & ~(uptr)POOL_SIZE_MASK))
+
+/* Return total number of blocks in pool of size index I, as a uint. */
+#define NUMBLOCKS(I) ((uint)(POOL_SIZE - POOL_OVERHEAD) / INDEX2SIZE(I))
+
+/*==========================================================================*/
+
+/*
+ * This malloc lock
+ */
+SIMPLELOCK_DECL(_malloc_lock)
+#define LOCK() SIMPLELOCK_LOCK(_malloc_lock)
+#define UNLOCK() SIMPLELOCK_UNLOCK(_malloc_lock)
+#define LOCK_INIT() SIMPLELOCK_INIT(_malloc_lock)
+#define LOCK_FINI() SIMPLELOCK_FINI(_malloc_lock)
+
+/*
+ * Pool table -- headed, circular, doubly-linked lists of partially used pools.
+
+This is involved. For an index i, usedpools[i+i] is the header for a list of
+all partially used pools holding small blocks with "size class idx" i. So
+usedpools[0] corresponds to blocks of size 8, usedpools[2] to blocks of size
+16, and so on: index 2*i <-> blocks of size (i+1)<<ALIGNMENT_SHIFT.
+
+Pools are carved off an arena's highwater mark (an arena_object's pool_address
+member) as needed. Once carved off, a pool is in one of three states forever
+after:
+
+used == partially used, neither empty nor full
+ At least one block in the pool is currently allocated, and at least one
+ block in the pool is not currently allocated (note this implies a pool
+ has room for at least two blocks).
+ This is a pool's initial state, as a pool is created only when malloc
+ needs space.
+ The pool holds blocks of a fixed size, and is in the circular list headed
+ at usedpools[i] (see above). It's linked to the other used pools of the
+ same size class via the pool_header's nextpool and prevpool members.
+ If all but one block is currently allocated, a malloc can cause a
+ transition to the full state. If all but one block is not currently
+ allocated, a free can cause a transition to the empty state.
+
+full == all the pool's blocks are currently allocated
+ On transition to full, a pool is unlinked from its usedpools[] list.
+ It's not linked to from anything then anymore, and its nextpool and
+ prevpool members are meaningless until it transitions back to used.
+ A free of a block in a full pool puts the pool back in the used state.
+ Then it's linked in at the front of the appropriate usedpools[] list, so
+ that the next allocation for its size class will reuse the freed block.
+
+empty == all the pool's blocks are currently available for allocation
+ On transition to empty, a pool is unlinked from its usedpools[] list,
+ and linked to the front of its arena_object's singly-linked freepools list,
+ via its nextpool member. The prevpool member has no meaning in this case.
+ Empty pools have no inherent size class: the next time a malloc finds
+ an empty list in usedpools[], it takes the first pool off of freepools.
+ If the size class needed happens to be the same as the size class the pool
+ last had, some pool initialization can be skipped.
+
+
+Block Management
+
+Blocks within pools are again carved out as needed. pool->freeblock points to
+the start of a singly-linked list of free blocks within the pool. When a
+block is freed, it's inserted at the front of its pool's freeblock list. Note
+that the available blocks in a pool are *not* linked all together when a pool
+is initialized. Instead only "the first two" (lowest addresses) blocks are
+set up, returning the first such block, and setting pool->freeblock to a
+one-block list holding the second such block. This is consistent with that
+pymalloc strives at all levels (arena, pool, and block) never to touch a piece
+of memory until it's actually needed.
+
+So long as a pool is in the used state, we're certain there *is* a block
+available for allocating, and pool->freeblock is not NULL. If pool->freeblock
+points to the end of the free list before we've carved the entire pool into
+blocks, that means we simply haven't yet gotten to one of the higher-address
+blocks. The offset from the pool_header to the start of "the next" virgin
+block is stored in the pool_header nextoffset member, and the largest value
+of nextoffset that makes sense is stored in the maxnextoffset member when a
+pool is initialized. All the blocks in a pool have been passed out at least
+once when and only when nextoffset > maxnextoffset.
+
+
+Major obscurity: While the usedpools vector is declared to have poolp
+entries, it doesn't really. It really contains two pointers per (conceptual)
+poolp entry, the nextpool and prevpool members of a pool_header. The
+excruciating initialization code below fools C so that
+
+ usedpool[i+i]
+
+"acts like" a genuine poolp, but only so long as you only reference its
+nextpool and prevpool members. The "- 2*sizeof(block *)" gibberish is
+compensating for that a pool_header's nextpool and prevpool members
+immediately follow a pool_header's first two members:
+
+ union { block *_padding;
+ uint count; } ref;
+ block *freeblock;
+
+each of which consume sizeof(block *) bytes. So what usedpools[i+i] really
+contains is a fudged-up pointer p such that *if* C believes it's a poolp
+pointer, then p->nextpool and p->prevpool are both p (meaning that the headed
+circular list is empty).
+
+It's unclear why the usedpools setup is so convoluted. It could be to
+minimize the amount of cache required to hold this heavily-referenced table
+(which only *needs* the two interpool pointer members of a pool_header). OTOH,
+referencing code has to remember to "double the index" and doing so isn't
+free, usedpools[0] isn't a strictly legal pointer, and we're crucially relying
+on that C doesn't insert any padding anywhere in a pool_header at or before
+the prevpool member.
+**************************************************************************** */
+
+#define PTA(x) ((poolp )((uchar *)&(usedpools[2*(x)]) - 2*sizeof(block *)))
+#define PT(x) PTA(x), PTA(x)
+
+static poolp usedpools[2 * ((NB_SMALL_SIZE_CLASSES + 7) / 8) * 8] = {
+ PT(0), PT(1), PT(2), PT(3), PT(4), PT(5), PT(6), PT(7)
+#if NB_SMALL_SIZE_CLASSES > 8
+ , PT(8), PT(9), PT(10), PT(11), PT(12), PT(13), PT(14), PT(15)
+#if NB_SMALL_SIZE_CLASSES > 16
+ , PT(16), PT(17), PT(18), PT(19), PT(20), PT(21), PT(22), PT(23)
+#if NB_SMALL_SIZE_CLASSES > 24
+ , PT(24), PT(25), PT(26), PT(27), PT(28), PT(29), PT(30), PT(31)
+#if NB_SMALL_SIZE_CLASSES > 32
+ , PT(32), PT(33), PT(34), PT(35), PT(36), PT(37), PT(38), PT(39)
+#if NB_SMALL_SIZE_CLASSES > 40
+ , PT(40), PT(41), PT(42), PT(43), PT(44), PT(45), PT(46), PT(47)
+#if NB_SMALL_SIZE_CLASSES > 48
+ , PT(48), PT(49), PT(50), PT(51), PT(52), PT(53), PT(54), PT(55)
+#if NB_SMALL_SIZE_CLASSES > 56
+ , PT(56), PT(57), PT(58), PT(59), PT(60), PT(61), PT(62), PT(63)
+#if NB_SMALL_SIZE_CLASSES > 64
+#error "NB_SMALL_SIZE_CLASSES should be less than 64"
+#endif /* NB_SMALL_SIZE_CLASSES > 64 */
+#endif /* NB_SMALL_SIZE_CLASSES > 56 */
+#endif /* NB_SMALL_SIZE_CLASSES > 48 */
+#endif /* NB_SMALL_SIZE_CLASSES > 40 */
+#endif /* NB_SMALL_SIZE_CLASSES > 32 */
+#endif /* NB_SMALL_SIZE_CLASSES > 24 */
+#endif /* NB_SMALL_SIZE_CLASSES > 16 */
+#endif /* NB_SMALL_SIZE_CLASSES > 8 */
+};
+
+/*==========================================================================
+Arena management.
+
+`arenas` is a vector of arena_objects. It contains maxarenas entries, some of
+which may not be currently used (== they're arena_objects that aren't
+currently associated with an allocated arena). Note that arenas proper are
+separately malloc'ed.
+
+Prior to Python 2.5, arenas were never free()'ed. Starting with Python 2.5,
+we do try to free() arenas, and use some mild heuristic strategies to increase
+the likelihood that arenas eventually can be freed.
+
+unused_arena_objects
+
+ This is a singly-linked list of the arena_objects that are currently not
+ being used (no arena is associated with them). Objects are taken off the
+ head of the list in new_arena(), and are pushed on the head of the list in
+ PyObject_Free() when the arena is empty. Key invariant: an arena_object
+ is on this list if and only if its .address member is 0.
+
+usable_arenas
+
+ This is a doubly-linked list of the arena_objects associated with arenas
+ that have pools available. These pools are either waiting to be reused,
+ or have not been used before. The list is sorted to have the most-
+ allocated arenas first (ascending order based on the nfreepools member).
+ This means that the next allocation will come from a heavily used arena,
+ which gives the nearly empty arenas a chance to be returned to the system.
+ In my unscientific tests this dramatically improved the number of arenas
+ that could be freed.
+
+Note that an arena_object associated with an arena all of whose pools are
+currently in use isn't on either list.
+*/
+
+/* Array of objects used to track chunks of memory (arenas). */
+static struct arena_object* arenas = NULL;
+/* Number of slots currently allocated in the `arenas` vector. */
+static uint maxarenas = 0;
+
+/* The head of the singly-linked, NULL-terminated list of available
+ * arena_objects.
+ */
+static struct arena_object* unused_arena_objects = NULL;
+
+/* The head of the doubly-linked, NULL-terminated at each end, list of
+ * arena_objects associated with arenas that have pools available.
+ */
+static struct arena_object* usable_arenas = NULL;
+
+/* How many arena_objects do we initially allocate?
+ * 16 = can allocate 16 arenas = 16 * ARENA_SIZE = 4MB before growing the
+ * `arenas` vector.
+ */
+#define INITIAL_ARENA_OBJECTS 16
+
+/* Number of arenas allocated that haven't been free()'d. */
+static size_t narenas_currently_allocated = 0;
+
+#ifdef PYMALLOC_DEBUG
+/* Total number of times malloc() called to allocate an arena. */
+static size_t ntimes_arena_allocated = 0;
+/* High water mark (max value ever seen) for narenas_currently_allocated. */
+static size_t narenas_highwater = 0;
+#endif
+
+/* Allocate a new arena. If we run out of memory, return NULL. Else
+ * allocate a new arena, and return the address of an arena_object
+ * describing the new arena. It's expected that the caller will set
+ * `usable_arenas` to the return value.
+ */
+static struct arena_object*
+new_arena(void)
+{
+ struct arena_object* arenaobj;
+ uint excess; /* number of bytes above pool alignment */
+ void *address;
+ int err;
+
+#ifdef PYMALLOC_DEBUG
+ if (Py_GETENV("PYTHONMALLOCSTATS"))
+ _PyObject_DebugMallocStats();
+#endif
+ if (unused_arena_objects == NULL) {
+ uint i;
+ uint numarenas;
+ size_t nbytes;
+
+ /* Double the number of arena objects on each allocation.
+ * Note that it's possible for `numarenas` to overflow.
+ */
+ numarenas = maxarenas ? maxarenas << 1 : INITIAL_ARENA_OBJECTS;
+ if (numarenas <= maxarenas)
+ return NULL; /* overflow */
+#if SIZEOF_SIZE_T <= SIZEOF_INT
+ if (numarenas > PY_SIZE_MAX / sizeof(*arenas))
+ return NULL; /* overflow */
+#endif
+ nbytes = numarenas * sizeof(*arenas);
+ arenaobj = (struct arena_object *)realloc(arenas, nbytes);
+ if (arenaobj == NULL)
+ return NULL;
+ arenas = arenaobj;
+
+ /* We might need to fix pointers that were copied. However,
+ * new_arena only gets called when all the pages in the
+ * previous arenas are full. Thus, there are *no* pointers
+ * into the old array. Thus, we don't have to worry about
+ * invalid pointers. Just to be sure, some asserts:
+ */
+ assert(usable_arenas == NULL);
+ assert(unused_arena_objects == NULL);
+
+ /* Put the new arenas on the unused_arena_objects list. */
+ for (i = maxarenas; i < numarenas; ++i) {
+ arenas[i].address = 0; /* mark as unassociated */
+ arenas[i].nextarena = i < numarenas - 1 ?
+ &arenas[i+1] : NULL;
+ }
+
+ /* Update globals. */
+ unused_arena_objects = &arenas[maxarenas];
+ maxarenas = numarenas;
+ }
+
+ /* Take the next available arena object off the head of the list. */
+ assert(unused_arena_objects != NULL);
+ arenaobj = unused_arena_objects;
+ unused_arena_objects = arenaobj->nextarena;
+ assert(arenaobj->address == 0);
+#ifdef ARENAS_USE_MMAP
+ address = mmap(NULL, ARENA_SIZE, PROT_READ|PROT_WRITE,
+ MAP_PRIVATE|MAP_ANONYMOUS, -1, 0);
+ err = (address == MAP_FAILED);
+#else
+ address = malloc(ARENA_SIZE);
+ err = (address == 0);
+#endif
+ if (err) {
+ /* The allocation failed: return NULL after putting the
+ * arenaobj back.
+ */
+ arenaobj->nextarena = unused_arena_objects;
+ unused_arena_objects = arenaobj;
+ return NULL;
+ }
+ arenaobj->address = (uptr)address;
+
+ ++narenas_currently_allocated;
+#ifdef PYMALLOC_DEBUG
+ ++ntimes_arena_allocated;
+ if (narenas_currently_allocated > narenas_highwater)
+ narenas_highwater = narenas_currently_allocated;
+#endif
+ arenaobj->freepools = NULL;
+ /* pool_address <- first pool-aligned address in the arena
+ nfreepools <- number of whole pools that fit after alignment */
+ arenaobj->pool_address = (block*)arenaobj->address;
+ arenaobj->nfreepools = ARENA_SIZE / POOL_SIZE;
+ assert(POOL_SIZE * arenaobj->nfreepools == ARENA_SIZE);
+ excess = (uint)(arenaobj->address & POOL_SIZE_MASK);
+ if (excess != 0) {
+ --arenaobj->nfreepools;
+ arenaobj->pool_address += POOL_SIZE - excess;
+ }
+ arenaobj->ntotalpools = arenaobj->nfreepools;
+
+ return arenaobj;
+}
+
+/*
+Py_ADDRESS_IN_RANGE(P, POOL)
+
+Return true if and only if P is an address that was allocated by pymalloc.
+POOL must be the pool address associated with P, i.e., POOL = POOL_ADDR(P)
+(the caller is asked to compute this because the macro expands POOL more than
+once, and for efficiency it's best for the caller to assign POOL_ADDR(P) to a
+variable and pass the latter to the macro; because Py_ADDRESS_IN_RANGE is
+called on every alloc/realloc/free, micro-efficiency is important here).
+
+Tricky: Let B be the arena base address associated with the pool, B =
+arenas[(POOL)->arenaindex].address. Then P belongs to the arena if and only if
+
+ B <= P < B + ARENA_SIZE
+
+Subtracting B throughout, this is true iff
+
+ 0 <= P-B < ARENA_SIZE
+
+By using unsigned arithmetic, the "0 <=" half of the test can be skipped.
+
+Obscure: A PyMem "free memory" function can call the pymalloc free or realloc
+before the first arena has been allocated. `arenas` is still NULL in that
+case. We're relying on that maxarenas is also 0 in that case, so that
+(POOL)->arenaindex < maxarenas must be false, saving us from trying to index
+into a NULL arenas.
+
+Details: given P and POOL, the arena_object corresponding to P is AO =
+arenas[(POOL)->arenaindex]. Suppose obmalloc controls P. Then (barring wild
+stores, etc), POOL is the correct address of P's pool, AO.address is the
+correct base address of the pool's arena, and P must be within ARENA_SIZE of
+AO.address. In addition, AO.address is not 0 (no arena can start at address 0
+(NULL)). Therefore Py_ADDRESS_IN_RANGE correctly reports that obmalloc
+controls P.
+
+Now suppose obmalloc does not control P (e.g., P was obtained via a direct
+call to the system malloc() or realloc()). (POOL)->arenaindex may be anything
+in this case -- it may even be uninitialized trash. If the trash arenaindex
+is >= maxarenas, the macro correctly concludes at once that obmalloc doesn't
+control P.
+
+Else arenaindex is < maxarena, and AO is read up. If AO corresponds to an
+allocated arena, obmalloc controls all the memory in slice AO.address :
+AO.address+ARENA_SIZE. By case assumption, P is not controlled by obmalloc,
+so P doesn't lie in that slice, so the macro correctly reports that P is not
+controlled by obmalloc.
+
+Finally, if P is not controlled by obmalloc and AO corresponds to an unused
+arena_object (one not currently associated with an allocated arena),
+AO.address is 0, and the second test in the macro reduces to:
+
+ P < ARENA_SIZE
+
+If P >= ARENA_SIZE (extremely likely), the macro again correctly concludes
+that P is not controlled by obmalloc. However, if P < ARENA_SIZE, this part
+of the test still passes, and the third clause (AO.address != 0) is necessary
+to get the correct result: AO.address is 0 in this case, so the macro
+correctly reports that P is not controlled by obmalloc (despite that P lies in
+slice AO.address : AO.address + ARENA_SIZE).
+
+Note: The third (AO.address != 0) clause was added in Python 2.5. Before
+2.5, arenas were never free()'ed, and an arenaindex < maxarena always
+corresponded to a currently-allocated arena, so the "P is not controlled by
+obmalloc, AO corresponds to an unused arena_object, and P < ARENA_SIZE" case
+was impossible.
+
+Note that the logic is excruciating, and reading up possibly uninitialized
+memory when P is not controlled by obmalloc (to get at (POOL)->arenaindex)
+creates problems for some memory debuggers. The overwhelming advantage is
+that this test determines whether an arbitrary address is controlled by
+obmalloc in a small constant time, independent of the number of arenas
+obmalloc controls. Since this test is needed at every entry point, it's
+extremely desirable that it be this fast.
+
+Since Py_ADDRESS_IN_RANGE may be reading from memory which was not allocated
+by Python, it is important that (POOL)->arenaindex is read only once, as
+another thread may be concurrently modifying the value without holding the
+GIL. To accomplish this, the arenaindex_temp variable is used to store
+(POOL)->arenaindex for the duration of the Py_ADDRESS_IN_RANGE macro's
+execution. The caller of the macro is responsible for declaring this
+variable.
+*/
+#define Py_ADDRESS_IN_RANGE(P, POOL) \
+ ((arenaindex_temp = (POOL)->arenaindex) < maxarenas && \
+ (uptr)(P) - arenas[arenaindex_temp].address < (uptr)ARENA_SIZE && \
+ arenas[arenaindex_temp].address != 0)
+
+
+/* This is only useful when running memory debuggers such as
+ * Purify or Valgrind. Uncomment to use.
+ *
+#define Py_USING_MEMORY_DEBUGGER
+ */
+
+#ifdef Py_USING_MEMORY_DEBUGGER
+
+/* Py_ADDRESS_IN_RANGE may access uninitialized memory by design
+ * This leads to thousands of spurious warnings when using
+ * Purify or Valgrind. By making a function, we can easily
+ * suppress the uninitialized memory reads in this one function.
+ * So we won't ignore real errors elsewhere.
+ *
+ * Disable the macro and use a function.
+ */
+
+#undef Py_ADDRESS_IN_RANGE
+
+#if defined(__GNUC__) && ((__GNUC__ == 3) && (__GNUC_MINOR__ >= 1) || \
+ (__GNUC__ >= 4))
+#define Py_NO_INLINE __attribute__((__noinline__))
+#else
+#define Py_NO_INLINE
+#endif
+
+/* Don't make static, to try to ensure this isn't inlined. */
+int Py_ADDRESS_IN_RANGE(void *P, poolp pool) Py_NO_INLINE;
+#undef Py_NO_INLINE
+#endif
+
+/*==========================================================================*/
+
+/* malloc. Note that nbytes==0 tries to return a non-NULL pointer, distinct
+ * from all other currently live pointers. This may not be possible.
+ */
+
+/*
+ * The basic blocks are ordered by decreasing execution frequency,
+ * which minimizes the number of jumps in the most common cases,
+ * improves branching prediction and instruction scheduling (small
+ * block allocations typically result in a couple of instructions).
+ * Unless the optimizer reorders everything, being too smart...
+ */
+
+#undef PyObject_Malloc
+void *
+PyObject_Malloc(size_t nbytes)
+{
+ block *bp;
+ poolp pool;
+ poolp next;
+ uint size;
+
+#ifdef WITH_VALGRIND
+ if (UNLIKELY(running_on_valgrind == -1))
+ running_on_valgrind = RUNNING_ON_VALGRIND;
+ if (UNLIKELY(running_on_valgrind))
+ goto redirect;
+#endif
+
+ /*
+ * Limit ourselves to PY_SSIZE_T_MAX bytes to prevent security holes.
+ * Most python internals blindly use a signed Py_ssize_t to track
+ * things without checking for overflows or negatives.
+ * As size_t is unsigned, checking for nbytes < 0 is not required.
+ */
+ if (nbytes > PY_SSIZE_T_MAX)
+ return NULL;
+
+ /*
+ * This implicitly redirects malloc(0).
+ */
+ if ((nbytes - 1) < SMALL_REQUEST_THRESHOLD) {
+ LOCK();
+ /*
+ * Most frequent paths first
+ */
+ size = (uint)(nbytes - 1) >> ALIGNMENT_SHIFT;
+ pool = usedpools[size + size];
+ if (pool != pool->nextpool) {
+ /*
+ * There is a used pool for this size class.
+ * Pick up the head block of its free list.
+ */
+ ++pool->ref.count;
+ bp = pool->freeblock;
+ assert(bp != NULL);
+ if ((pool->freeblock = *(block **)bp) != NULL) {
+ UNLOCK();
+ return (void *)bp;
+ }
+ /*
+ * Reached the end of the free list, try to extend it.
+ */
+ if (pool->nextoffset <= pool->maxnextoffset) {
+ /* There is room for another block. */
+ pool->freeblock = (block*)pool +
+ pool->nextoffset;
+ pool->nextoffset += INDEX2SIZE(size);
+ *(block **)(pool->freeblock) = NULL;
+ UNLOCK();
+ return (void *)bp;
+ }
+ /* Pool is full, unlink from used pools. */
+ next = pool->nextpool;
+ pool = pool->prevpool;
+ next->prevpool = pool;
+ pool->nextpool = next;
+ UNLOCK();
+ return (void *)bp;
+ }
+
+ /* There isn't a pool of the right size class immediately
+ * available: use a free pool.
+ */
+ if (usable_arenas == NULL) {
+ /* No arena has a free pool: allocate a new arena. */
+#ifdef WITH_MEMORY_LIMITS
+ if (narenas_currently_allocated >= MAX_ARENAS) {
+ UNLOCK();
+ goto redirect;
+ }
+#endif
+ usable_arenas = new_arena();
+ if (usable_arenas == NULL) {
+ UNLOCK();
+ goto redirect;
+ }
+ usable_arenas->nextarena =
+ usable_arenas->prevarena = NULL;
+ }
+ assert(usable_arenas->address != 0);
+
+ /* Try to get a cached free pool. */
+ pool = usable_arenas->freepools;
+ if (pool != NULL) {
+ /* Unlink from cached pools. */
+ usable_arenas->freepools = pool->nextpool;
+
+ /* This arena already had the smallest nfreepools
+ * value, so decreasing nfreepools doesn't change
+ * that, and we don't need to rearrange the
+ * usable_arenas list. However, if the arena has
+ * become wholly allocated, we need to remove its
+ * arena_object from usable_arenas.
+ */
+ --usable_arenas->nfreepools;
+ if (usable_arenas->nfreepools == 0) {
+ /* Wholly allocated: remove. */
+ assert(usable_arenas->freepools == NULL);
+ assert(usable_arenas->nextarena == NULL ||
+ usable_arenas->nextarena->prevarena ==
+ usable_arenas);
+
+ usable_arenas = usable_arenas->nextarena;
+ if (usable_arenas != NULL) {
+ usable_arenas->prevarena = NULL;
+ assert(usable_arenas->address != 0);
+ }
+ }
+ else {
+ /* nfreepools > 0: it must be that freepools
+ * isn't NULL, or that we haven't yet carved
+ * off all the arena's pools for the first
+ * time.
+ */
+ assert(usable_arenas->freepools != NULL ||
+ usable_arenas->pool_address <=
+ (block*)usable_arenas->address +
+ ARENA_SIZE - POOL_SIZE);
+ }
+ init_pool:
+ /* Frontlink to used pools. */
+ next = usedpools[size + size]; /* == prev */
+ pool->nextpool = next;
+ pool->prevpool = next;
+ next->nextpool = pool;
+ next->prevpool = pool;
+ pool->ref.count = 1;
+ if (pool->szidx == size) {
+ /* Luckily, this pool last contained blocks
+ * of the same size class, so its header
+ * and free list are already initialized.
+ */
+ bp = pool->freeblock;
+ pool->freeblock = *(block **)bp;
+ UNLOCK();
+ return (void *)bp;
+ }
+ /*
+ * Initialize the pool header, set up the free list to
+ * contain just the second block, and return the first
+ * block.
+ */
+ pool->szidx = size;
+ size = INDEX2SIZE(size);
+ bp = (block *)pool + POOL_OVERHEAD;
+ pool->nextoffset = POOL_OVERHEAD + (size << 1);
+ pool->maxnextoffset = POOL_SIZE - size;
+ pool->freeblock = bp + size;
+ *(block **)(pool->freeblock) = NULL;
+ UNLOCK();
+ return (void *)bp;
+ }
+
+ /* Carve off a new pool. */
+ assert(usable_arenas->nfreepools > 0);
+ assert(usable_arenas->freepools == NULL);
+ pool = (poolp)usable_arenas->pool_address;
+ assert((block*)pool <= (block*)usable_arenas->address +
+ ARENA_SIZE - POOL_SIZE);
+ pool->arenaindex = usable_arenas - arenas;
+ assert(&arenas[pool->arenaindex] == usable_arenas);
+ pool->szidx = DUMMY_SIZE_IDX;
+ usable_arenas->pool_address += POOL_SIZE;
+ --usable_arenas->nfreepools;
+
+ if (usable_arenas->nfreepools == 0) {
+ assert(usable_arenas->nextarena == NULL ||
+ usable_arenas->nextarena->prevarena ==
+ usable_arenas);
+ /* Unlink the arena: it is completely allocated. */
+ usable_arenas = usable_arenas->nextarena;
+ if (usable_arenas != NULL) {
+ usable_arenas->prevarena = NULL;
+ assert(usable_arenas->address != 0);
+ }
+ }
+
+ goto init_pool;
+ }
+
+ /* The small block allocator ends here. */
+
+redirect:
+ /* Redirect the original request to the underlying (libc) allocator.
+ * We jump here on bigger requests, on error in the code above (as a
+ * last chance to serve the request) or when the max memory limit
+ * has been reached.
+ */
+ if (nbytes == 0)
+ nbytes = 1;
+ return (void *)malloc(nbytes);
+}
+
+/* free */
+
+#undef PyObject_Free
+ATTRIBUTE_NO_ADDRESS_SAFETY_ANALYSIS
+void
+PyObject_Free(void *p)
+{
+ poolp pool;
+ block *lastfree;
+ poolp next, prev;
+ uint size;
+#ifndef Py_USING_MEMORY_DEBUGGER
+ uint arenaindex_temp;
+#endif
+
+ if (p == NULL) /* free(NULL) has no effect */
+ return;
+
+#ifdef WITH_VALGRIND
+ if (UNLIKELY(running_on_valgrind > 0))
+ goto redirect;
+#endif
+
+ pool = POOL_ADDR(p);
+ if (Py_ADDRESS_IN_RANGE(p, pool)) {
+ /* We allocated this address. */
+ LOCK();
+ /* Link p to the start of the pool's freeblock list. Since
+ * the pool had at least the p block outstanding, the pool
+ * wasn't empty (so it's already in a usedpools[] list, or
+ * was full and is in no list -- it's not in the freeblocks
+ * list in any case).
+ */
+ assert(pool->ref.count > 0); /* else it was empty */
+ *(block **)p = lastfree = pool->freeblock;
+ pool->freeblock = (block *)p;
+ if (lastfree) {
+ struct arena_object* ao;
+ uint nf; /* ao->nfreepools */
+
+ /* freeblock wasn't NULL, so the pool wasn't full,
+ * and the pool is in a usedpools[] list.
+ */
+ if (--pool->ref.count != 0) {
+ /* pool isn't empty: leave it in usedpools */
+ UNLOCK();
+ return;
+ }
+ /* Pool is now empty: unlink from usedpools, and
+ * link to the front of freepools. This ensures that
+ * previously freed pools will be allocated later
+ * (being not referenced, they are perhaps paged out).
+ */
+ next = pool->nextpool;
+ prev = pool->prevpool;
+ next->prevpool = prev;
+ prev->nextpool = next;
+
+ /* Link the pool to freepools. This is a singly-linked
+ * list, and pool->prevpool isn't used there.
+ */
+ ao = &arenas[pool->arenaindex];
+ pool->nextpool = ao->freepools;
+ ao->freepools = pool;
+ nf = ++ao->nfreepools;
+
+ /* All the rest is arena management. We just freed
+ * a pool, and there are 4 cases for arena mgmt:
+ * 1. If all the pools are free, return the arena to
+ * the system free().
+ * 2. If this is the only free pool in the arena,
+ * add the arena back to the `usable_arenas` list.
+ * 3. If the "next" arena has a smaller count of free
+ * pools, we have to "slide this arena right" to
+ * restore that usable_arenas is sorted in order of
+ * nfreepools.
+ * 4. Else there's nothing more to do.
+ */
+ if (nf == ao->ntotalpools) {
+ /* Case 1. First unlink ao from usable_arenas.
+ */
+ assert(ao->prevarena == NULL ||
+ ao->prevarena->address != 0);
+ assert(ao ->nextarena == NULL ||
+ ao->nextarena->address != 0);
+
+ /* Fix the pointer in the prevarena, or the
+ * usable_arenas pointer.
+ */
+ if (ao->prevarena == NULL) {
+ usable_arenas = ao->nextarena;
+ assert(usable_arenas == NULL ||
+ usable_arenas->address != 0);
+ }
+ else {
+ assert(ao->prevarena->nextarena == ao);
+ ao->prevarena->nextarena =
+ ao->nextarena;
+ }
+ /* Fix the pointer in the nextarena. */
+ if (ao->nextarena != NULL) {
+ assert(ao->nextarena->prevarena == ao);
+ ao->nextarena->prevarena =
+ ao->prevarena;
+ }
+ /* Record that this arena_object slot is
+ * available to be reused.
+ */
+ ao->nextarena = unused_arena_objects;
+ unused_arena_objects = ao;
+
+ /* Free the entire arena. */
+#ifdef ARENAS_USE_MMAP
+ munmap((void *)ao->address, ARENA_SIZE);
+#else
+ free((void *)ao->address);
+#endif
+ ao->address = 0; /* mark unassociated */
+ --narenas_currently_allocated;
+
+ UNLOCK();
+ return;
+ }
+ if (nf == 1) {
+ /* Case 2. Put ao at the head of
+ * usable_arenas. Note that because
+ * ao->nfreepools was 0 before, ao isn't
+ * currently on the usable_arenas list.
+ */
+ ao->nextarena = usable_arenas;
+ ao->prevarena = NULL;
+ if (usable_arenas)
+ usable_arenas->prevarena = ao;
+ usable_arenas = ao;
+ assert(usable_arenas->address != 0);
+
+ UNLOCK();
+ return;
+ }
+ /* If this arena is now out of order, we need to keep
+ * the list sorted. The list is kept sorted so that
+ * the "most full" arenas are used first, which allows
+ * the nearly empty arenas to be completely freed. In
+ * a few un-scientific tests, it seems like this
+ * approach allowed a lot more memory to be freed.
+ */
+ if (ao->nextarena == NULL ||
+ nf <= ao->nextarena->nfreepools) {
+ /* Case 4. Nothing to do. */
+ UNLOCK();
+ return;
+ }
+ /* Case 3: We have to move the arena towards the end
+ * of the list, because it has more free pools than
+ * the arena to its right.
+ * First unlink ao from usable_arenas.
+ */
+ if (ao->prevarena != NULL) {
+ /* ao isn't at the head of the list */
+ assert(ao->prevarena->nextarena == ao);
+ ao->prevarena->nextarena = ao->nextarena;
+ }
+ else {
+ /* ao is at the head of the list */
+ assert(usable_arenas == ao);
+ usable_arenas = ao->nextarena;
+ }
+ ao->nextarena->prevarena = ao->prevarena;
+
+ /* Locate the new insertion point by iterating over
+ * the list, using our nextarena pointer.
+ */
+ while (ao->nextarena != NULL &&
+ nf > ao->nextarena->nfreepools) {
+ ao->prevarena = ao->nextarena;
+ ao->nextarena = ao->nextarena->nextarena;
+ }
+
+ /* Insert ao at this point. */
+ assert(ao->nextarena == NULL ||
+ ao->prevarena == ao->nextarena->prevarena);
+ assert(ao->prevarena->nextarena == ao->nextarena);
+
+ ao->prevarena->nextarena = ao;
+ if (ao->nextarena != NULL)
+ ao->nextarena->prevarena = ao;
+
+ /* Verify that the swaps worked. */
+ assert(ao->nextarena == NULL ||
+ nf <= ao->nextarena->nfreepools);
+ assert(ao->prevarena == NULL ||
+ nf > ao->prevarena->nfreepools);
+ assert(ao->nextarena == NULL ||
+ ao->nextarena->prevarena == ao);
+ assert((usable_arenas == ao &&
+ ao->prevarena == NULL) ||
+ ao->prevarena->nextarena == ao);
+
+ UNLOCK();
+ return;
+ }
+ /* Pool was full, so doesn't currently live in any list:
+ * link it to the front of the appropriate usedpools[] list.
+ * This mimics LRU pool usage for new allocations and
+ * targets optimal filling when several pools contain
+ * blocks of the same size class.
+ */
+ --pool->ref.count;
+ assert(pool->ref.count > 0); /* else the pool is empty */
+ size = pool->szidx;
+ next = usedpools[size + size];
+ prev = next->prevpool;
+ /* insert pool before next: prev <-> pool <-> next */
+ pool->nextpool = next;
+ pool->prevpool = prev;
+ next->prevpool = pool;
+ prev->nextpool = pool;
+ UNLOCK();
+ return;
+ }
+
+#ifdef WITH_VALGRIND
+redirect:
+#endif
+ /* We didn't allocate this address. */
+ free(p);
+}
+
+/* realloc. If p is NULL, this acts like malloc(nbytes). Else if nbytes==0,
+ * then as the Python docs promise, we do not treat this like free(p), and
+ * return a non-NULL result.
+ */
+
+#undef PyObject_Realloc
+ATTRIBUTE_NO_ADDRESS_SAFETY_ANALYSIS
+void *
+PyObject_Realloc(void *p, size_t nbytes)
+{
+ void *bp;
+ poolp pool;
+ size_t size;
+#ifndef Py_USING_MEMORY_DEBUGGER
+ uint arenaindex_temp;
+#endif
+
+ if (p == NULL)
+ return PyObject_Malloc(nbytes);
+
+ /*
+ * Limit ourselves to PY_SSIZE_T_MAX bytes to prevent security holes.
+ * Most python internals blindly use a signed Py_ssize_t to track
+ * things without checking for overflows or negatives.
+ * As size_t is unsigned, checking for nbytes < 0 is not required.
+ */
+ if (nbytes > PY_SSIZE_T_MAX)
+ return NULL;
+
+#ifdef WITH_VALGRIND
+ /* Treat running_on_valgrind == -1 the same as 0 */
+ if (UNLIKELY(running_on_valgrind > 0))
+ goto redirect;
+#endif
+
+ pool = POOL_ADDR(p);
+ if (Py_ADDRESS_IN_RANGE(p, pool)) {
+ /* We're in charge of this block */
+ size = INDEX2SIZE(pool->szidx);
+ if (nbytes <= size) {
+ /* The block is staying the same or shrinking. If
+ * it's shrinking, there's a tradeoff: it costs
+ * cycles to copy the block to a smaller size class,
+ * but it wastes memory not to copy it. The
+ * compromise here is to copy on shrink only if at
+ * least 25% of size can be shaved off.
+ */
+ if (4 * nbytes > 3 * size) {
+ /* It's the same,
+ * or shrinking and new/old > 3/4.
+ */
+ return p;
+ }
+ size = nbytes;
+ }
+ bp = PyObject_Malloc(nbytes);
+ if (bp != NULL) {
+ memcpy(bp, p, size);
+ PyObject_Free(p);
+ }
+ return bp;
+ }
+#ifdef WITH_VALGRIND
+ redirect:
+#endif
+ /* We're not managing this block. If nbytes <=
+ * SMALL_REQUEST_THRESHOLD, it's tempting to try to take over this
+ * block. However, if we do, we need to copy the valid data from
+ * the C-managed block to one of our blocks, and there's no portable
+ * way to know how much of the memory space starting at p is valid.
+ * As bug 1185883 pointed out the hard way, it's possible that the
+ * C-managed block is "at the end" of allocated VM space, so that
+ * a memory fault can occur if we try to copy nbytes bytes starting
+ * at p. Instead we punt: let C continue to manage this block.
+ */
+ if (nbytes)
+ return realloc(p, nbytes);
+ /* C doesn't define the result of realloc(p, 0) (it may or may not
+ * return NULL then), but Python's docs promise that nbytes==0 never
+ * returns NULL. We don't pass 0 to realloc(), to avoid that endcase
+ * to begin with. Even then, we can't be sure that realloc() won't
+ * return NULL.
+ */
+ bp = realloc(p, 1);
+ return bp ? bp : p;
+}
+
+#else /* ! WITH_PYMALLOC */
+
+/*==========================================================================*/
+/* pymalloc not enabled: Redirect the entry points to malloc. These will
+ * only be used by extensions that are compiled with pymalloc enabled. */
+
+void *
+PyObject_Malloc(size_t n)
+{
+ return PyMem_MALLOC(n);
+}
+
+void *
+PyObject_Realloc(void *p, size_t n)
+{
+ return PyMem_REALLOC(p, n);
+}
+
+void
+PyObject_Free(void *p)
+{
+ PyMem_FREE(p);
+}
+#endif /* WITH_PYMALLOC */
+
+#ifdef PYMALLOC_DEBUG
+/*==========================================================================*/
+/* A x-platform debugging allocator. This doesn't manage memory directly,
+ * it wraps a real allocator, adding extra debugging info to the memory blocks.
+ */
+
+/* Special bytes broadcast into debug memory blocks at appropriate times.
+ * Strings of these are unlikely to be valid addresses, floats, ints or
+ * 7-bit ASCII.
+ */
+#undef CLEANBYTE
+#undef DEADBYTE
+#undef FORBIDDENBYTE
+#define CLEANBYTE 0xCB /* clean (newly allocated) memory */
+#define DEADBYTE 0xDB /* dead (newly freed) memory */
+#define FORBIDDENBYTE 0xFB /* untouchable bytes at each end of a block */
+
+/* We tag each block with an API ID in order to tag API violations */
+#define _PYMALLOC_MEM_ID 'm' /* the PyMem_Malloc() API */
+#define _PYMALLOC_OBJ_ID 'o' /* The PyObject_Malloc() API */
+
+static size_t serialno = 0; /* incremented on each debug {m,re}alloc */
+
+/* serialno is always incremented via calling this routine. The point is
+ * to supply a single place to set a breakpoint.
+ */
+static void
+bumpserialno(void)
+{
+ ++serialno;
+}
+
+#define SST SIZEOF_SIZE_T
+
+/* Read sizeof(size_t) bytes at p as a big-endian size_t. */
+static size_t
+read_size_t(const void *p)
+{
+ const uchar *q = (const uchar *)p;
+ size_t result = *q++;
+ int i;
+
+ for (i = SST; --i > 0; ++q)
+ result = (result << 8) | *q;
+ return result;
+}
+
+/* Write n as a big-endian size_t, MSB at address p, LSB at
+ * p + sizeof(size_t) - 1.
+ */
+static void
+write_size_t(void *p, size_t n)
+{
+ uchar *q = (uchar *)p + SST - 1;
+ int i;
+
+ for (i = SST; --i >= 0; --q) {
+ *q = (uchar)(n & 0xff);
+ n >>= 8;
+ }
+}
+
+#ifdef Py_DEBUG
+/* Is target in the list? The list is traversed via the nextpool pointers.
+ * The list may be NULL-terminated, or circular. Return 1 if target is in
+ * list, else 0.
+ */
+static int
+pool_is_in_list(const poolp target, poolp list)
+{
+ poolp origlist = list;
+ assert(target != NULL);
+ if (list == NULL)
+ return 0;
+ do {
+ if (target == list)
+ return 1;
+ list = list->nextpool;
+ } while (list != NULL && list != origlist);
+ return 0;
+}
+
+#else
+#define pool_is_in_list(X, Y) 1
+
+#endif /* Py_DEBUG */
+
+/* Let S = sizeof(size_t). The debug malloc asks for 4*S extra bytes and
+ fills them with useful stuff, here calling the underlying malloc's result p:
+
+p[0: S]
+ Number of bytes originally asked for. This is a size_t, big-endian (easier
+ to read in a memory dump).
+p[S: 2*S]
+ Copies of FORBIDDENBYTE. Used to catch under- writes and reads.
+p[2*S: 2*S+n]
+ The requested memory, filled with copies of CLEANBYTE.
+ Used to catch reference to uninitialized memory.
+ &p[2*S] is returned. Note that this is 8-byte aligned if pymalloc
+ handled the request itself.
+p[2*S+n: 2*S+n+S]
+ Copies of FORBIDDENBYTE. Used to catch over- writes and reads.
+p[2*S+n+S: 2*S+n+2*S]
+ A serial number, incremented by 1 on each call to _PyObject_DebugMalloc
+ and _PyObject_DebugRealloc.
+ This is a big-endian size_t.
+ If "bad memory" is detected later, the serial number gives an
+ excellent way to set a breakpoint on the next run, to capture the
+ instant at which this block was passed out.
+*/
+
+/* debug replacements for the PyMem_* memory API */
+void *
+_PyMem_DebugMalloc(size_t nbytes)
+{
+ return _PyObject_DebugMallocApi(_PYMALLOC_MEM_ID, nbytes);
+}
+void *
+_PyMem_DebugRealloc(void *p, size_t nbytes)
+{
+ return _PyObject_DebugReallocApi(_PYMALLOC_MEM_ID, p, nbytes);
+}
+void
+_PyMem_DebugFree(void *p)
+{
+ _PyObject_DebugFreeApi(_PYMALLOC_MEM_ID, p);
+}
+
+/* debug replacements for the PyObject_* memory API */
+void *
+_PyObject_DebugMalloc(size_t nbytes)
+{
+ return _PyObject_DebugMallocApi(_PYMALLOC_OBJ_ID, nbytes);
+}
+void *
+_PyObject_DebugRealloc(void *p, size_t nbytes)
+{
+ return _PyObject_DebugReallocApi(_PYMALLOC_OBJ_ID, p, nbytes);
+}
+void
+_PyObject_DebugFree(void *p)
+{
+ _PyObject_DebugFreeApi(_PYMALLOC_OBJ_ID, p);
+}
+void
+_PyObject_DebugCheckAddress(const void *p)
+{
+ _PyObject_DebugCheckAddressApi(_PYMALLOC_OBJ_ID, p);
+}
+
+
+/* generic debug memory api, with an "id" to identify the API in use */
+void *
+_PyObject_DebugMallocApi(char id, size_t nbytes)
+{
+ uchar *p; /* base address of malloc'ed block */
+ uchar *tail; /* p + 2*SST + nbytes == pointer to tail pad bytes */
+ size_t total; /* nbytes + 4*SST */
+
+ bumpserialno();
+ total = nbytes + 4*SST;
+ if (total < nbytes)
+ /* overflow: can't represent total as a size_t */
+ return NULL;
+
+ p = (uchar *)PyObject_Malloc(total);
+ if (p == NULL)
+ return NULL;
+
+ /* at p, write size (SST bytes), id (1 byte), pad (SST-1 bytes) */
+ write_size_t(p, nbytes);
+ p[SST] = (uchar)id;
+ memset(p + SST + 1 , FORBIDDENBYTE, SST-1);
+
+ if (nbytes > 0)
+ memset(p + 2*SST, CLEANBYTE, nbytes);
+
+ /* at tail, write pad (SST bytes) and serialno (SST bytes) */
+ tail = p + 2*SST + nbytes;
+ memset(tail, FORBIDDENBYTE, SST);
+ write_size_t(tail + SST, serialno);
+
+ return p + 2*SST;
+}
+
+/* The debug free first checks the 2*SST bytes on each end for sanity (in
+ particular, that the FORBIDDENBYTEs with the api ID are still intact).
+ Then fills the original bytes with DEADBYTE.
+ Then calls the underlying free.
+*/
+void
+_PyObject_DebugFreeApi(char api, void *p)
+{
+ uchar *q = (uchar *)p - 2*SST; /* address returned from malloc */
+ size_t nbytes;
+
+ if (p == NULL)
+ return;
+ _PyObject_DebugCheckAddressApi(api, p);
+ nbytes = read_size_t(q);
+ nbytes += 4*SST;
+ if (nbytes > 0)
+ memset(q, DEADBYTE, nbytes);
+ PyObject_Free(q);
+}
+
+void *
+_PyObject_DebugReallocApi(char api, void *p, size_t nbytes)
+{
+ uchar *q = (uchar *)p;
+ uchar *tail;
+ size_t total; /* nbytes + 4*SST */
+ size_t original_nbytes;
+ int i;
+
+ if (p == NULL)
+ return _PyObject_DebugMallocApi(api, nbytes);
+
+ _PyObject_DebugCheckAddressApi(api, p);
+ bumpserialno();
+ original_nbytes = read_size_t(q - 2*SST);
+ total = nbytes + 4*SST;
+ if (total < nbytes)
+ /* overflow: can't represent total as a size_t */
+ return NULL;
+
+ if (nbytes < original_nbytes) {
+ /* shrinking: mark old extra memory dead */
+ memset(q + nbytes, DEADBYTE, original_nbytes - nbytes + 2*SST);
+ }
+
+ /* Resize and add decorations. We may get a new pointer here, in which
+ * case we didn't get the chance to mark the old memory with DEADBYTE,
+ * but we live with that.
+ */
+ q = (uchar *)PyObject_Realloc(q - 2*SST, total);
+ if (q == NULL)
+ return NULL;
+
+ write_size_t(q, nbytes);
+ assert(q[SST] == (uchar)api);
+ for (i = 1; i < SST; ++i)
+ assert(q[SST + i] == FORBIDDENBYTE);
+ q += 2*SST;
+ tail = q + nbytes;
+ memset(tail, FORBIDDENBYTE, SST);
+ write_size_t(tail + SST, serialno);
+
+ if (nbytes > original_nbytes) {
+ /* growing: mark new extra memory clean */
+ memset(q + original_nbytes, CLEANBYTE,
+ nbytes - original_nbytes);
+ }
+
+ return q;
+}
+
+/* Check the forbidden bytes on both ends of the memory allocated for p.
+ * If anything is wrong, print info to stderr via _PyObject_DebugDumpAddress,
+ * and call Py_FatalError to kill the program.
+ * The API id, is also checked.
+ */
+ void
+_PyObject_DebugCheckAddressApi(char api, const void *p)
+{
+ const uchar *q = (const uchar *)p;
+ char msgbuf[64];
+ char *msg;
+ size_t nbytes;
+ const uchar *tail;
+ int i;
+ char id;
+
+ if (p == NULL) {
+ msg = "didn't expect a NULL pointer";
+ goto error;
+ }
+
+ /* Check the API id */
+ id = (char)q[-SST];
+ if (id != api) {
+ msg = msgbuf;
+ snprintf(msg, sizeof(msgbuf), "bad ID: Allocated using API '%c', verified using API '%c'", id, api);
+ msgbuf[sizeof(msgbuf)-1] = 0;
+ goto error;
+ }
+
+ /* Check the stuff at the start of p first: if there's underwrite
+ * corruption, the number-of-bytes field may be nuts, and checking
+ * the tail could lead to a segfault then.
+ */
+ for (i = SST-1; i >= 1; --i) {
+ if (*(q-i) != FORBIDDENBYTE) {
+ msg = "bad leading pad byte";
+ goto error;
+ }
+ }
+
+ nbytes = read_size_t(q - 2*SST);
+ tail = q + nbytes;
+ for (i = 0; i < SST; ++i) {
+ if (tail[i] != FORBIDDENBYTE) {
+ msg = "bad trailing pad byte";
+ goto error;
+ }
+ }
+
+ return;
+
+error:
+ _PyObject_DebugDumpAddress(p);
+ Py_FatalError(msg);
+}
+
+/* Display info to stderr about the memory block at p. */
+void
+_PyObject_DebugDumpAddress(const void *p)
+{
+ const uchar *q = (const uchar *)p;
+ const uchar *tail;
+ size_t nbytes, serial;
+ int i;
+ int ok;
+ char id;
+
+ fprintf(stderr, "Debug memory block at address p=%p:", p);
+ if (p == NULL) {
+ fprintf(stderr, "\n");
+ return;
+ }
+ id = (char)q[-SST];
+ fprintf(stderr, " API '%c'\n", id);
+
+ nbytes = read_size_t(q - 2*SST);
+ fprintf(stderr, " %" PY_FORMAT_SIZE_T "u bytes originally "
+ "requested\n", nbytes);
+
+ /* In case this is nuts, check the leading pad bytes first. */
+ fprintf(stderr, " The %d pad bytes at p-%d are ", SST-1, SST-1);
+ ok = 1;
+ for (i = 1; i <= SST-1; ++i) {
+ if (*(q-i) != FORBIDDENBYTE) {
+ ok = 0;
+ break;
+ }
+ }
+ if (ok)
+ fputs("FORBIDDENBYTE, as expected.\n", stderr);
+ else {
+ fprintf(stderr, "not all FORBIDDENBYTE (0x%02x):\n",
+ FORBIDDENBYTE);
+ for (i = SST-1; i >= 1; --i) {
+ const uchar byte = *(q-i);
+ fprintf(stderr, " at p-%d: 0x%02x", i, byte);
+ if (byte != FORBIDDENBYTE)
+ fputs(" *** OUCH", stderr);
+ fputc('\n', stderr);
+ }
+
+ fputs(" Because memory is corrupted at the start, the "
+ "count of bytes requested\n"
+ " may be bogus, and checking the trailing pad "
+ "bytes may segfault.\n", stderr);
+ }
+
+ tail = q + nbytes;
+ fprintf(stderr, " The %d pad bytes at tail=%p are ", SST, tail);
+ ok = 1;
+ for (i = 0; i < SST; ++i) {
+ if (tail[i] != FORBIDDENBYTE) {
+ ok = 0;
+ break;
+ }
+ }
+ if (ok)
+ fputs("FORBIDDENBYTE, as expected.\n", stderr);
+ else {
+ fprintf(stderr, "not all FORBIDDENBYTE (0x%02x):\n",
+ FORBIDDENBYTE);
+ for (i = 0; i < SST; ++i) {
+ const uchar byte = tail[i];
+ fprintf(stderr, " at tail+%d: 0x%02x",
+ i, byte);
+ if (byte != FORBIDDENBYTE)
+ fputs(" *** OUCH", stderr);
+ fputc('\n', stderr);
+ }
+ }
+
+ serial = read_size_t(tail + SST);
+ fprintf(stderr, " The block was made by call #%" PY_FORMAT_SIZE_T
+ "u to debug malloc/realloc.\n", serial);
+
+ if (nbytes > 0) {
+ i = 0;
+ fputs(" Data at p:", stderr);
+ /* print up to 8 bytes at the start */
+ while (q < tail && i < 8) {
+ fprintf(stderr, " %02x", *q);
+ ++i;
+ ++q;
+ }
+ /* and up to 8 at the end */
+ if (q < tail) {
+ if (tail - q > 8) {
+ fputs(" ...", stderr);
+ q = tail - 8;
+ }
+ while (q < tail) {
+ fprintf(stderr, " %02x", *q);
+ ++q;
+ }
+ }
+ fputc('\n', stderr);
+ }
+}
+
+static size_t
+printone(const char* msg, size_t value)
+{
+ int i, k;
+ char buf[100];
+ size_t origvalue = value;
+
+ fputs(msg, stderr);
+ for (i = (int)strlen(msg); i < 35; ++i)
+ fputc(' ', stderr);
+ fputc('=', stderr);
+
+ /* Write the value with commas. */
+ i = 22;
+ buf[i--] = '\0';
+ buf[i--] = '\n';
+ k = 3;
+ do {
+ size_t nextvalue = value / 10;
+ unsigned int digit = (unsigned int)(value - nextvalue * 10);
+ value = nextvalue;
+ buf[i--] = (char)(digit + '0');
+ --k;
+ if (k == 0 && value && i >= 0) {
+ k = 3;
+ buf[i--] = ',';
+ }
+ } while (value && i >= 0);
+
+ while (i >= 0)
+ buf[i--] = ' ';
+ fputs(buf, stderr);
+
+ return origvalue;
+}
+
+/* Print summary info to stderr about the state of pymalloc's structures.
+ * In Py_DEBUG mode, also perform some expensive internal consistency
+ * checks.
+ */
+void
+_PyObject_DebugMallocStats(void)
+{
+ uint i;
+ const uint numclasses = SMALL_REQUEST_THRESHOLD >> ALIGNMENT_SHIFT;
+ /* # of pools, allocated blocks, and free blocks per class index */
+ size_t numpools[SMALL_REQUEST_THRESHOLD >> ALIGNMENT_SHIFT];
+ size_t numblocks[SMALL_REQUEST_THRESHOLD >> ALIGNMENT_SHIFT];
+ size_t numfreeblocks[SMALL_REQUEST_THRESHOLD >> ALIGNMENT_SHIFT];
+ /* total # of allocated bytes in used and full pools */
+ size_t allocated_bytes = 0;
+ /* total # of available bytes in used pools */
+ size_t available_bytes = 0;
+ /* # of free pools + pools not yet carved out of current arena */
+ uint numfreepools = 0;
+ /* # of bytes for arena alignment padding */
+ size_t arena_alignment = 0;
+ /* # of bytes in used and full pools used for pool_headers */
+ size_t pool_header_bytes = 0;
+ /* # of bytes in used and full pools wasted due to quantization,
+ * i.e. the necessarily leftover space at the ends of used and
+ * full pools.
+ */
+ size_t quantization = 0;
+ /* # of arenas actually allocated. */
+ size_t narenas = 0;
+ /* running total -- should equal narenas * ARENA_SIZE */
+ size_t total;
+ char buf[128];
+
+ fprintf(stderr, "Small block threshold = %d, in %u size classes.\n",
+ SMALL_REQUEST_THRESHOLD, numclasses);
+
+ for (i = 0; i < numclasses; ++i)
+ numpools[i] = numblocks[i] = numfreeblocks[i] = 0;
+
+ /* Because full pools aren't linked to from anything, it's easiest
+ * to march over all the arenas. If we're lucky, most of the memory
+ * will be living in full pools -- would be a shame to miss them.
+ */
+ for (i = 0; i < maxarenas; ++i) {
+ uint j;
+ uptr base = arenas[i].address;
+
+ /* Skip arenas which are not allocated. */
+ if (arenas[i].address == (uptr)NULL)
+ continue;
+ narenas += 1;
+
+ numfreepools += arenas[i].nfreepools;
+
+ /* round up to pool alignment */
+ if (base & (uptr)POOL_SIZE_MASK) {
+ arena_alignment += POOL_SIZE;
+ base &= ~(uptr)POOL_SIZE_MASK;
+ base += POOL_SIZE;
+ }
+
+ /* visit every pool in the arena */
+ assert(base <= (uptr) arenas[i].pool_address);
+ for (j = 0;
+ base < (uptr) arenas[i].pool_address;
+ ++j, base += POOL_SIZE) {
+ poolp p = (poolp)base;
+ const uint sz = p->szidx;
+ uint freeblocks;
+
+ if (p->ref.count == 0) {
+ /* currently unused */
+ assert(pool_is_in_list(p, arenas[i].freepools));
+ continue;
+ }
+ ++numpools[sz];
+ numblocks[sz] += p->ref.count;
+ freeblocks = NUMBLOCKS(sz) - p->ref.count;
+ numfreeblocks[sz] += freeblocks;
+#ifdef Py_DEBUG
+ if (freeblocks > 0)
+ assert(pool_is_in_list(p, usedpools[sz + sz]));
+#endif
+ }
+ }
+ assert(narenas == narenas_currently_allocated);
+
+ fputc('\n', stderr);
+ fputs("class size num pools blocks in use avail blocks\n"
+ "----- ---- --------- ------------- ------------\n",
+ stderr);
+
+ for (i = 0; i < numclasses; ++i) {
+ size_t p = numpools[i];
+ size_t b = numblocks[i];
+ size_t f = numfreeblocks[i];
+ uint size = INDEX2SIZE(i);
+ if (p == 0) {
+ assert(b == 0 && f == 0);
+ continue;
+ }
+ fprintf(stderr, "%5u %6u "
+ "%11" PY_FORMAT_SIZE_T "u "
+ "%15" PY_FORMAT_SIZE_T "u "
+ "%13" PY_FORMAT_SIZE_T "u\n",
+ i, size, p, b, f);
+ allocated_bytes += b * size;
+ available_bytes += f * size;
+ pool_header_bytes += p * POOL_OVERHEAD;
+ quantization += p * ((POOL_SIZE - POOL_OVERHEAD) % size);
+ }
+ fputc('\n', stderr);
+ (void)printone("# times object malloc called", serialno);
+
+ (void)printone("# arenas allocated total", ntimes_arena_allocated);
+ (void)printone("# arenas reclaimed", ntimes_arena_allocated - narenas);
+ (void)printone("# arenas highwater mark", narenas_highwater);
+ (void)printone("# arenas allocated current", narenas);
+
+ PyOS_snprintf(buf, sizeof(buf),
+ "%" PY_FORMAT_SIZE_T "u arenas * %d bytes/arena",
+ narenas, ARENA_SIZE);
+ (void)printone(buf, narenas * ARENA_SIZE);
+
+ fputc('\n', stderr);
+
+ total = printone("# bytes in allocated blocks", allocated_bytes);
+ total += printone("# bytes in available blocks", available_bytes);
+
+ PyOS_snprintf(buf, sizeof(buf),
+ "%u unused pools * %d bytes", numfreepools, POOL_SIZE);
+ total += printone(buf, (size_t)numfreepools * POOL_SIZE);
+
+ total += printone("# bytes lost to pool headers", pool_header_bytes);
+ total += printone("# bytes lost to quantization", quantization);
+ total += printone("# bytes lost to arena alignment", arena_alignment);
+ (void)printone("Total", total);
+}
+
+#endif /* PYMALLOC_DEBUG */
+
+#ifdef Py_USING_MEMORY_DEBUGGER
+/* Make this function last so gcc won't inline it since the definition is
+ * after the reference.
+ */
+int
+Py_ADDRESS_IN_RANGE(void *P, poolp pool)
+{
+ uint arenaindex_temp = pool->arenaindex;
+
+ return arenaindex_temp < maxarenas &&
+ (uptr)P - arenas[arenaindex_temp].address < (uptr)ARENA_SIZE &&
+ arenas[arenaindex_temp].address != 0;
+}
+#endif
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