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mimalloc/include/mimalloc-internal.h
David Carlier e6c2fd44fc DragonFly support fix (for 5.8.x and forward). 
The pthread slot approach is somewhat buggy (pretty visible
 with the stress unit test which segfault more or less randomly,
 but the stats never show up).
Using the default approach instead, the test passes eventough
 it s relatively slow (e.g 1.5 sec on FreeBSD vs 4.5 on DragonFly with same
 machine).
2020-10-22 11:15:37 +01:00

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/* ----------------------------------------------------------------------------
Copyright (c) 2018, Microsoft Research, Daan Leijen
This is free software; you can redistribute it and/or modify it under the
terms of the MIT license. A copy of the license can be found in the file
"LICENSE" at the root of this distribution.
-----------------------------------------------------------------------------*/
#pragma once
#ifndef MIMALLOC_INTERNAL_H
#define MIMALLOC_INTERNAL_H
#include "mimalloc-types.h"
#if (MI_DEBUG>0)
#define mi_trace_message(...) _mi_trace_message(__VA_ARGS__)
#else
#define mi_trace_message(...)
#endif
#define MI_CACHE_LINE 64
#if defined(_MSC_VER)
#pragma warning(disable:4127) // suppress constant conditional warning (due to MI_SECURE paths)
#define mi_decl_noinline __declspec(noinline)
#define mi_decl_thread __declspec(thread)
#define mi_decl_cache_align __declspec(align(MI_CACHE_LINE))
#elif (defined(__GNUC__) && (__GNUC__>=3)) // includes clang and icc
#define mi_decl_noinline __attribute__((noinline))
#define mi_decl_thread __thread
#define mi_decl_cache_align __attribute__((aligned(MI_CACHE_LINE)))
#else
#define mi_decl_noinline
#define mi_decl_thread __thread // hope for the best :-)
#define mi_decl_cache_align
#endif
// "options.c"
void _mi_fputs(mi_output_fun* out, void* arg, const char* prefix, const char* message);
void _mi_fprintf(mi_output_fun* out, void* arg, const char* fmt, ...);
void _mi_warning_message(const char* fmt, ...);
void _mi_verbose_message(const char* fmt, ...);
void _mi_trace_message(const char* fmt, ...);
void _mi_options_init(void);
void _mi_error_message(int err, const char* fmt, ...);
// random.c
void _mi_random_init(mi_random_ctx_t* ctx);
void _mi_random_split(mi_random_ctx_t* ctx, mi_random_ctx_t* new_ctx);
uintptr_t _mi_random_next(mi_random_ctx_t* ctx);
uintptr_t _mi_heap_random_next(mi_heap_t* heap);
uintptr_t _os_random_weak(uintptr_t extra_seed);
static inline uintptr_t _mi_random_shuffle(uintptr_t x);
// init.c
extern mi_stats_t _mi_stats_main;
extern const mi_page_t _mi_page_empty;
bool _mi_is_main_thread(void);
bool _mi_preloading(); // true while the C runtime is not ready
// os.c
size_t _mi_os_page_size(void);
void _mi_os_init(void); // called from process init
void* _mi_os_alloc(size_t size, mi_stats_t* stats); // to allocate thread local data
void _mi_os_free(void* p, size_t size, mi_stats_t* stats); // to free thread local data
size_t _mi_os_good_alloc_size(size_t size);
// memory.c
void* _mi_mem_alloc_aligned(size_t size, size_t alignment, bool* commit, bool* large, bool* is_pinned, bool* is_zero, size_t* id, mi_os_tld_t* tld);
void _mi_mem_free(void* p, size_t size, size_t id, bool fully_committed, bool any_reset, mi_os_tld_t* tld);
bool _mi_mem_reset(void* p, size_t size, mi_os_tld_t* tld);
bool _mi_mem_unreset(void* p, size_t size, bool* is_zero, mi_os_tld_t* tld);
bool _mi_mem_commit(void* p, size_t size, bool* is_zero, mi_os_tld_t* tld);
bool _mi_mem_protect(void* addr, size_t size);
bool _mi_mem_unprotect(void* addr, size_t size);
void _mi_mem_collect(mi_os_tld_t* tld);
// "segment.c"
mi_page_t* _mi_segment_page_alloc(mi_heap_t* heap, size_t block_wsize, mi_segments_tld_t* tld, mi_os_tld_t* os_tld);
void _mi_segment_page_free(mi_page_t* page, bool force, mi_segments_tld_t* tld);
void _mi_segment_page_abandon(mi_page_t* page, mi_segments_tld_t* tld);
uint8_t* _mi_segment_page_start(const mi_segment_t* segment, const mi_page_t* page, size_t block_size, size_t* page_size, size_t* pre_size); // page start for any page
void _mi_segment_huge_page_free(mi_segment_t* segment, mi_page_t* page, mi_block_t* block);
void _mi_segment_thread_collect(mi_segments_tld_t* tld);
void _mi_abandoned_reclaim_all(mi_heap_t* heap, mi_segments_tld_t* tld);
void _mi_abandoned_await_readers(void);
// "page.c"
void* _mi_malloc_generic(mi_heap_t* heap, size_t size) mi_attr_noexcept mi_attr_malloc;
void _mi_page_retire(mi_page_t* page); // free the page if there are no other pages with many free blocks
void _mi_page_unfull(mi_page_t* page);
void _mi_page_free(mi_page_t* page, mi_page_queue_t* pq, bool force); // free the page
void _mi_page_abandon(mi_page_t* page, mi_page_queue_t* pq); // abandon the page, to be picked up by another thread...
void _mi_heap_delayed_free(mi_heap_t* heap);
void _mi_heap_collect_retired(mi_heap_t* heap, bool force);
void _mi_page_use_delayed_free(mi_page_t* page, mi_delayed_t delay, bool override_never);
size_t _mi_page_queue_append(mi_heap_t* heap, mi_page_queue_t* pq, mi_page_queue_t* append);
void _mi_deferred_free(mi_heap_t* heap, bool force);
void _mi_page_free_collect(mi_page_t* page,bool force);
void _mi_page_reclaim(mi_heap_t* heap, mi_page_t* page); // callback from segments
size_t _mi_bin_size(uint8_t bin); // for stats
uint8_t _mi_bin(size_t size); // for stats
// "heap.c"
void _mi_heap_destroy_pages(mi_heap_t* heap);
void _mi_heap_collect_abandon(mi_heap_t* heap);
void _mi_heap_set_default_direct(mi_heap_t* heap);
// "stats.c"
void _mi_stats_done(mi_stats_t* stats);
mi_msecs_t _mi_clock_now(void);
mi_msecs_t _mi_clock_end(mi_msecs_t start);
mi_msecs_t _mi_clock_start(void);
// "alloc.c"
void* _mi_page_malloc(mi_heap_t* heap, mi_page_t* page, size_t size) mi_attr_noexcept; // called from `_mi_malloc_generic`
void* _mi_heap_malloc_zero(mi_heap_t* heap, size_t size, bool zero);
void* _mi_heap_realloc_zero(mi_heap_t* heap, void* p, size_t newsize, bool zero);
mi_block_t* _mi_page_ptr_unalign(const mi_segment_t* segment, const mi_page_t* page, const void* p);
bool _mi_free_delayed_block(mi_block_t* block);
void _mi_block_zero_init(const mi_page_t* page, void* p, size_t size);
#if MI_DEBUG>1
bool _mi_page_is_valid(mi_page_t* page);
#endif
// ------------------------------------------------------
// Branches
// ------------------------------------------------------
#if defined(__GNUC__) || defined(__clang__)
#define mi_unlikely(x) __builtin_expect((x),0)
#define mi_likely(x) __builtin_expect((x),1)
#else
#define mi_unlikely(x) (x)
#define mi_likely(x) (x)
#endif
#ifndef __has_builtin
#define __has_builtin(x) 0
#endif
/* -----------------------------------------------------------
Error codes passed to `_mi_fatal_error`
All are recoverable but EFAULT is a serious error and aborts by default in secure mode.
For portability define undefined error codes using common Unix codes:
<https://www-numi.fnal.gov/offline_software/srt_public_context/WebDocs/Errors/unix_system_errors.html>
----------------------------------------------------------- */
#include <errno.h>
#ifndef EAGAIN // double free
#define EAGAIN (11)
#endif
#ifndef ENOMEM // out of memory
#define ENOMEM (12)
#endif
#ifndef EFAULT // corrupted free-list or meta-data
#define EFAULT (14)
#endif
#ifndef EINVAL // trying to free an invalid pointer
#define EINVAL (22)
#endif
#ifndef EOVERFLOW // count*size overflow
#define EOVERFLOW (75)
#endif
/* -----------------------------------------------------------
Inlined definitions
----------------------------------------------------------- */
#define UNUSED(x) (void)(x)
#if (MI_DEBUG>0)
#define UNUSED_RELEASE(x)
#else
#define UNUSED_RELEASE(x) UNUSED(x)
#endif
#define MI_INIT4(x) x(),x(),x(),x()
#define MI_INIT8(x) MI_INIT4(x),MI_INIT4(x)
#define MI_INIT16(x) MI_INIT8(x),MI_INIT8(x)
#define MI_INIT32(x) MI_INIT16(x),MI_INIT16(x)
#define MI_INIT64(x) MI_INIT32(x),MI_INIT32(x)
#define MI_INIT128(x) MI_INIT64(x),MI_INIT64(x)
#define MI_INIT256(x) MI_INIT128(x),MI_INIT128(x)
// Is `x` a power of two? (0 is considered a power of two)
static inline bool _mi_is_power_of_two(uintptr_t x) {
return ((x & (x - 1)) == 0);
}
// Align upwards
static inline uintptr_t _mi_align_up(uintptr_t sz, size_t alignment) {
mi_assert_internal(alignment != 0);
uintptr_t mask = alignment - 1;
if ((alignment & mask) == 0) { // power of two?
return ((sz + mask) & ~mask);
}
else {
return (((sz + mask)/alignment)*alignment);
}
}
// Divide upwards: `s <= _mi_divide_up(s,d)*d < s+d`.
static inline uintptr_t _mi_divide_up(uintptr_t size, size_t divider) {
mi_assert_internal(divider != 0);
return (divider == 0 ? size : ((size + divider - 1) / divider));
}
// Is memory zero initialized?
static inline bool mi_mem_is_zero(void* p, size_t size) {
for (size_t i = 0; i < size; i++) {
if (((uint8_t*)p)[i] != 0) return false;
}
return true;
}
// Align a byte size to a size in _machine words_,
// i.e. byte size == `wsize*sizeof(void*)`.
static inline size_t _mi_wsize_from_size(size_t size) {
mi_assert_internal(size <= SIZE_MAX - sizeof(uintptr_t));
return (size + sizeof(uintptr_t) - 1) / sizeof(uintptr_t);
}
// Does malloc satisfy the alignment constraints already?
static inline bool mi_malloc_satisfies_alignment(size_t alignment, size_t size) {
return (alignment == sizeof(void*) || (alignment == MI_MAX_ALIGN_SIZE && size > (MI_MAX_ALIGN_SIZE/2)));
}
// Overflow detecting multiply
#if __has_builtin(__builtin_umul_overflow) || __GNUC__ >= 5
#include <limits.h> // UINT_MAX, ULONG_MAX
#if defined(_CLOCK_T) // for Illumos
#undef _CLOCK_T
#endif
static inline bool mi_mul_overflow(size_t count, size_t size, size_t* total) {
#if (SIZE_MAX == UINT_MAX)
return __builtin_umul_overflow(count, size, total);
#elif (SIZE_MAX == ULONG_MAX)
return __builtin_umull_overflow(count, size, total);
#else
return __builtin_umulll_overflow(count, size, total);
#endif
}
#else /* __builtin_umul_overflow is unavailable */
static inline bool mi_mul_overflow(size_t count, size_t size, size_t* total) {
#define MI_MUL_NO_OVERFLOW ((size_t)1 << (4*sizeof(size_t))) // sqrt(SIZE_MAX)
*total = count * size;
return ((size >= MI_MUL_NO_OVERFLOW || count >= MI_MUL_NO_OVERFLOW)
&& size > 0 && (SIZE_MAX / size) < count);
}
#endif
// Safe multiply `count*size` into `total`; return `true` on overflow.
static inline bool mi_count_size_overflow(size_t count, size_t size, size_t* total) {
if (count==1) { // quick check for the case where count is one (common for C++ allocators)
*total = size;
return false;
}
else if (mi_unlikely(mi_mul_overflow(count, size, total))) {
_mi_error_message(EOVERFLOW, "allocation request is too large (%zu * %zu bytes)\n", count, size);
*total = SIZE_MAX;
return true;
}
else return false;
}
/* ----------------------------------------------------------------------------------------
The thread local default heap: `_mi_get_default_heap` returns the thread local heap.
On most platforms (Windows, Linux, FreeBSD, NetBSD, etc), this just returns a
__thread local variable (`_mi_heap_default`). With the initial-exec TLS model this ensures
that the storage will always be available (allocated on the thread stacks).
On some platforms though we cannot use that when overriding `malloc` since the underlying
TLS implementation (or the loader) will call itself `malloc` on a first access and recurse.
We try to circumvent this in an efficient way:
- macOSX : we use an unused TLS slot from the OS allocated slots (MI_TLS_SLOT). On OSX, the
loader itself calls `malloc` even before the modules are initialized.
- OpenBSD: we use an unused slot from the pthread block (MI_TLS_PTHREAD_SLOT_OFS).
- DragonFly: the uniqueid use is buggy but kept for reference.
------------------------------------------------------------------------------------------- */
extern const mi_heap_t _mi_heap_empty; // read-only empty heap, initial value of the thread local default heap
extern bool _mi_process_is_initialized;
mi_heap_t* _mi_heap_main_get(void); // statically allocated main backing heap
#if defined(MI_MALLOC_OVERRIDE)
#if defined(__MACH__) // OSX
#define MI_TLS_SLOT 89 // seems unused?
// other possible unused ones are 9, 29, __PTK_FRAMEWORK_JAVASCRIPTCORE_KEY4 (94), __PTK_FRAMEWORK_GC_KEY9 (112) and __PTK_FRAMEWORK_OLDGC_KEY9 (89)
// see <https://github.com/rweichler/substrate/blob/master/include/pthread_machdep.h>
#elif defined(__OpenBSD__)
// use end bytes of a name; goes wrong if anyone uses names > 23 characters (ptrhread specifies 16)
// see <https://github.com/openbsd/src/blob/master/lib/libc/include/thread_private.h#L371>
#define MI_TLS_PTHREAD_SLOT_OFS (6*sizeof(int) + 4*sizeof(void*) + 24)
#elif defined(__DragonFly__)
#warning "mimalloc is not working correctly on DragonFly yet."
//#define MI_TLS_PTHREAD_SLOT_OFS (4 + 1*sizeof(void*)) // offset `uniqueid` (also used by gdb?) <https://github.com/DragonFlyBSD/DragonFlyBSD/blob/master/lib/libthread_xu/thread/thr_private.h#L458>
#endif
#endif
#if defined(MI_TLS_SLOT)
static inline void* mi_tls_slot(size_t slot) mi_attr_noexcept; // forward declaration
#elif defined(MI_TLS_PTHREAD_SLOT_OFS)
#include <pthread.h>
static inline mi_heap_t** mi_tls_pthread_heap_slot(void) {
pthread_t self = pthread_self();
#if defined(__DragonFly__)
if (self==NULL) {
mi_heap_t* pheap_main = _mi_heap_main_get();
return &pheap_main;
}
#endif
return (mi_heap_t**)((uint8_t*)self + MI_TLS_PTHREAD_SLOT_OFS);
}
#elif defined(MI_TLS_PTHREAD)
#include <pthread.h>
extern pthread_key_t _mi_heap_default_key;
#else
extern mi_decl_thread mi_heap_t* _mi_heap_default; // default heap to allocate from
#endif
static inline mi_heap_t* mi_get_default_heap(void) {
#if defined(MI_TLS_SLOT)
mi_heap_t* heap = (mi_heap_t*)mi_tls_slot(MI_TLS_SLOT);
return (mi_unlikely(heap == NULL) ? (mi_heap_t*)&_mi_heap_empty : heap);
#elif defined(MI_TLS_PTHREAD_SLOT_OFS)
mi_heap_t* heap = *mi_tls_pthread_heap_slot();
return (mi_unlikely(heap == NULL) ? (mi_heap_t*)&_mi_heap_empty : heap);
#elif defined(MI_TLS_PTHREAD)
mi_heap_t* heap = (mi_unlikely(_mi_heap_default_key == (pthread_key_t)(-1)) ? _mi_heap_main_get() : (mi_heap_t*)pthread_getspecific(_mi_heap_default_key));
return (mi_unlikely(heap == NULL) ? (mi_heap_t*)&_mi_heap_empty : heap);
#else
#if defined(MI_TLS_RECURSE_GUARD)
if (mi_unlikely(!_mi_process_is_initialized)) return _mi_heap_main_get();
#endif
return _mi_heap_default;
#endif
}
static inline bool mi_heap_is_default(const mi_heap_t* heap) {
return (heap == mi_get_default_heap());
}
static inline bool mi_heap_is_backing(const mi_heap_t* heap) {
return (heap->tld->heap_backing == heap);
}
static inline bool mi_heap_is_initialized(mi_heap_t* heap) {
mi_assert_internal(heap != NULL);
return (heap != &_mi_heap_empty);
}
static inline uintptr_t _mi_ptr_cookie(const void* p) {
extern mi_heap_t _mi_heap_main;
mi_assert_internal(_mi_heap_main.cookie != 0);
return ((uintptr_t)p ^ _mi_heap_main.cookie);
}
/* -----------------------------------------------------------
Pages
----------------------------------------------------------- */
static inline mi_page_t* _mi_heap_get_free_small_page(mi_heap_t* heap, size_t size) {
mi_assert_internal(size <= (MI_SMALL_SIZE_MAX + MI_PADDING_SIZE));
const size_t idx = _mi_wsize_from_size(size);
mi_assert_internal(idx < MI_PAGES_DIRECT);
return heap->pages_free_direct[idx];
}
// Get the page belonging to a certain size class
static inline mi_page_t* _mi_get_free_small_page(size_t size) {
return _mi_heap_get_free_small_page(mi_get_default_heap(), size);
}
// Segment that contains the pointer
static inline mi_segment_t* _mi_ptr_segment(const void* p) {
// mi_assert_internal(p != NULL);
return (mi_segment_t*)((uintptr_t)p & ~MI_SEGMENT_MASK);
}
// Segment belonging to a page
static inline mi_segment_t* _mi_page_segment(const mi_page_t* page) {
mi_segment_t* segment = _mi_ptr_segment(page);
mi_assert_internal(segment == NULL || page == &segment->pages[page->segment_idx]);
return segment;
}
// used internally
static inline uintptr_t _mi_segment_page_idx_of(const mi_segment_t* segment, const void* p) {
// if (segment->page_size > MI_SEGMENT_SIZE) return &segment->pages[0]; // huge pages
ptrdiff_t diff = (uint8_t*)p - (uint8_t*)segment;
mi_assert_internal(diff >= 0 && (size_t)diff < MI_SEGMENT_SIZE);
uintptr_t idx = (uintptr_t)diff >> segment->page_shift;
mi_assert_internal(idx < segment->capacity);
mi_assert_internal(segment->page_kind <= MI_PAGE_MEDIUM || idx == 0);
return idx;
}
// Get the page containing the pointer
static inline mi_page_t* _mi_segment_page_of(const mi_segment_t* segment, const void* p) {
uintptr_t idx = _mi_segment_page_idx_of(segment, p);
return &((mi_segment_t*)segment)->pages[idx];
}
// Quick page start for initialized pages
static inline uint8_t* _mi_page_start(const mi_segment_t* segment, const mi_page_t* page, size_t* page_size) {
const size_t bsize = page->xblock_size;
mi_assert_internal(bsize > 0 && (bsize%sizeof(void*)) == 0);
return _mi_segment_page_start(segment, page, bsize, page_size, NULL);
}
// Get the page containing the pointer
static inline mi_page_t* _mi_ptr_page(void* p) {
return _mi_segment_page_of(_mi_ptr_segment(p), p);
}
// Get the block size of a page (special cased for huge objects)
static inline size_t mi_page_block_size(const mi_page_t* page) {
const size_t bsize = page->xblock_size;
mi_assert_internal(bsize > 0);
if (mi_likely(bsize < MI_HUGE_BLOCK_SIZE)) {
return bsize;
}
else {
size_t psize;
_mi_segment_page_start(_mi_page_segment(page), page, bsize, &psize, NULL);
return psize;
}
}
// Get the usable block size of a page without fixed padding.
// This may still include internal padding due to alignment and rounding up size classes.
static inline size_t mi_page_usable_block_size(const mi_page_t* page) {
return mi_page_block_size(page) - MI_PADDING_SIZE;
}
// Thread free access
static inline mi_block_t* mi_page_thread_free(const mi_page_t* page) {
return (mi_block_t*)(mi_atomic_load_relaxed(&((mi_page_t*)page)->xthread_free) & ~3);
}
static inline mi_delayed_t mi_page_thread_free_flag(const mi_page_t* page) {
return (mi_delayed_t)(mi_atomic_load_relaxed(&((mi_page_t*)page)->xthread_free) & 3);
}
// Heap access
static inline mi_heap_t* mi_page_heap(const mi_page_t* page) {
return (mi_heap_t*)(mi_atomic_load_relaxed(&((mi_page_t*)page)->xheap));
}
static inline void mi_page_set_heap(mi_page_t* page, mi_heap_t* heap) {
mi_assert_internal(mi_page_thread_free_flag(page) != MI_DELAYED_FREEING);
mi_atomic_store_release(&page->xheap,(uintptr_t)heap);
}
// Thread free flag helpers
static inline mi_block_t* mi_tf_block(mi_thread_free_t tf) {
return (mi_block_t*)(tf & ~0x03);
}
static inline mi_delayed_t mi_tf_delayed(mi_thread_free_t tf) {
return (mi_delayed_t)(tf & 0x03);
}
static inline mi_thread_free_t mi_tf_make(mi_block_t* block, mi_delayed_t delayed) {
return (mi_thread_free_t)((uintptr_t)block | (uintptr_t)delayed);
}
static inline mi_thread_free_t mi_tf_set_delayed(mi_thread_free_t tf, mi_delayed_t delayed) {
return mi_tf_make(mi_tf_block(tf),delayed);
}
static inline mi_thread_free_t mi_tf_set_block(mi_thread_free_t tf, mi_block_t* block) {
return mi_tf_make(block, mi_tf_delayed(tf));
}
// are all blocks in a page freed?
// note: needs up-to-date used count, (as the `xthread_free` list may not be empty). see `_mi_page_collect_free`.
static inline bool mi_page_all_free(const mi_page_t* page) {
mi_assert_internal(page != NULL);
return (page->used == 0);
}
// are there any available blocks?
static inline bool mi_page_has_any_available(const mi_page_t* page) {
mi_assert_internal(page != NULL && page->reserved > 0);
return (page->used < page->reserved || (mi_page_thread_free(page) != NULL));
}
// are there immediately available blocks, i.e. blocks available on the free list.
static inline bool mi_page_immediate_available(const mi_page_t* page) {
mi_assert_internal(page != NULL);
return (page->free != NULL);
}
// is more than 7/8th of a page in use?
static inline bool mi_page_mostly_used(const mi_page_t* page) {
if (page==NULL) return true;
uint16_t frac = page->reserved / 8U;
return (page->reserved - page->used <= frac);
}
static inline mi_page_queue_t* mi_page_queue(const mi_heap_t* heap, size_t size) {
return &((mi_heap_t*)heap)->pages[_mi_bin(size)];
}
//-----------------------------------------------------------
// Page flags
//-----------------------------------------------------------
static inline bool mi_page_is_in_full(const mi_page_t* page) {
return page->flags.x.in_full;
}
static inline void mi_page_set_in_full(mi_page_t* page, bool in_full) {
page->flags.x.in_full = in_full;
}
static inline bool mi_page_has_aligned(const mi_page_t* page) {
return page->flags.x.has_aligned;
}
static inline void mi_page_set_has_aligned(mi_page_t* page, bool has_aligned) {
page->flags.x.has_aligned = has_aligned;
}
/* -------------------------------------------------------------------
Encoding/Decoding the free list next pointers
This is to protect against buffer overflow exploits where the
free list is mutated. Many hardened allocators xor the next pointer `p`
with a secret key `k1`, as `p^k1`. This prevents overwriting with known
values but might be still too weak: if the attacker can guess
the pointer `p` this can reveal `k1` (since `p^k1^p == k1`).
Moreover, if multiple blocks can be read as well, the attacker can
xor both as `(p1^k1) ^ (p2^k1) == p1^p2` which may reveal a lot
about the pointers (and subsequently `k1`).
Instead mimalloc uses an extra key `k2` and encodes as `((p^k2)<<<k1)+k1`.
Since these operations are not associative, the above approaches do not
work so well any more even if the `p` can be guesstimated. For example,
for the read case we can subtract two entries to discard the `+k1` term,
but that leads to `((p1^k2)<<<k1) - ((p2^k2)<<<k1)` at best.
We include the left-rotation since xor and addition are otherwise linear
in the lowest bit. Finally, both keys are unique per page which reduces
the re-use of keys by a large factor.
We also pass a separate `null` value to be used as `NULL` or otherwise
`(k2<<<k1)+k1` would appear (too) often as a sentinel value.
------------------------------------------------------------------- */
static inline bool mi_is_in_same_segment(const void* p, const void* q) {
return (_mi_ptr_segment(p) == _mi_ptr_segment(q));
}
static inline bool mi_is_in_same_page(const void* p, const void* q) {
mi_segment_t* segmentp = _mi_ptr_segment(p);
mi_segment_t* segmentq = _mi_ptr_segment(q);
if (segmentp != segmentq) return false;
uintptr_t idxp = _mi_segment_page_idx_of(segmentp, p);
uintptr_t idxq = _mi_segment_page_idx_of(segmentq, q);
return (idxp == idxq);
}
static inline uintptr_t mi_rotl(uintptr_t x, uintptr_t shift) {
shift %= MI_INTPTR_BITS;
return (shift==0 ? x : ((x << shift) | (x >> (MI_INTPTR_BITS - shift))));
}
static inline uintptr_t mi_rotr(uintptr_t x, uintptr_t shift) {
shift %= MI_INTPTR_BITS;
return (shift==0 ? x : ((x >> shift) | (x << (MI_INTPTR_BITS - shift))));
}
static inline void* mi_ptr_decode(const void* null, const mi_encoded_t x, const uintptr_t* keys) {
void* p = (void*)(mi_rotr(x - keys[0], keys[0]) ^ keys[1]);
return (mi_unlikely(p==null) ? NULL : p);
}
static inline mi_encoded_t mi_ptr_encode(const void* null, const void* p, const uintptr_t* keys) {
uintptr_t x = (uintptr_t)(mi_unlikely(p==NULL) ? null : p);
return mi_rotl(x ^ keys[1], keys[0]) + keys[0];
}
static inline mi_block_t* mi_block_nextx( const void* null, const mi_block_t* block, const uintptr_t* keys ) {
#ifdef MI_ENCODE_FREELIST
return (mi_block_t*)mi_ptr_decode(null, block->next, keys);
#else
UNUSED(keys); UNUSED(null);
return (mi_block_t*)block->next;
#endif
}
static inline void mi_block_set_nextx(const void* null, mi_block_t* block, const mi_block_t* next, const uintptr_t* keys) {
#ifdef MI_ENCODE_FREELIST
block->next = mi_ptr_encode(null, next, keys);
#else
UNUSED(keys); UNUSED(null);
block->next = (mi_encoded_t)next;
#endif
}
static inline mi_block_t* mi_block_next(const mi_page_t* page, const mi_block_t* block) {
#ifdef MI_ENCODE_FREELIST
mi_block_t* next = mi_block_nextx(page,block,page->keys);
// check for free list corruption: is `next` at least in the same page?
// TODO: check if `next` is `page->block_size` aligned?
if (mi_unlikely(next!=NULL && !mi_is_in_same_page(block, next))) {
_mi_error_message(EFAULT, "corrupted free list entry of size %zub at %p: value 0x%zx\n", mi_page_block_size(page), block, (uintptr_t)next);
next = NULL;
}
return next;
#else
UNUSED(page);
return mi_block_nextx(page,block,NULL);
#endif
}
static inline void mi_block_set_next(const mi_page_t* page, mi_block_t* block, const mi_block_t* next) {
#ifdef MI_ENCODE_FREELIST
mi_block_set_nextx(page,block,next, page->keys);
#else
UNUSED(page);
mi_block_set_nextx(page,block,next,NULL);
#endif
}
// -------------------------------------------------------------------
// Fast "random" shuffle
// -------------------------------------------------------------------
static inline uintptr_t _mi_random_shuffle(uintptr_t x) {
if (x==0) { x = 17; } // ensure we don't get stuck in generating zeros
#if (MI_INTPTR_SIZE==8)
// by Sebastiano Vigna, see: <http://xoshiro.di.unimi.it/splitmix64.c>
x ^= x >> 30;
x *= 0xbf58476d1ce4e5b9UL;
x ^= x >> 27;
x *= 0x94d049bb133111ebUL;
x ^= x >> 31;
#elif (MI_INTPTR_SIZE==4)
// by Chris Wellons, see: <https://nullprogram.com/blog/2018/07/31/>
x ^= x >> 16;
x *= 0x7feb352dUL;
x ^= x >> 15;
x *= 0x846ca68bUL;
x ^= x >> 16;
#endif
return x;
}
// -------------------------------------------------------------------
// Optimize numa node access for the common case (= one node)
// -------------------------------------------------------------------
int _mi_os_numa_node_get(mi_os_tld_t* tld);
size_t _mi_os_numa_node_count_get(void);
extern size_t _mi_numa_node_count;
static inline int _mi_os_numa_node(mi_os_tld_t* tld) {
if (mi_likely(_mi_numa_node_count == 1)) return 0;
else return _mi_os_numa_node_get(tld);
}
static inline size_t _mi_os_numa_node_count(void) {
if (mi_likely(_mi_numa_node_count>0)) return _mi_numa_node_count;
else return _mi_os_numa_node_count_get();
}
// -------------------------------------------------------------------
// Getting the thread id should be performant as it is called in the
// fast path of `_mi_free` and we specialize for various platforms.
// -------------------------------------------------------------------
#if defined(_WIN32)
#define WIN32_LEAN_AND_MEAN
#include <windows.h>
static inline uintptr_t _mi_thread_id(void) mi_attr_noexcept {
// Windows: works on Intel and ARM in both 32- and 64-bit
return (uintptr_t)NtCurrentTeb();
}
#elif defined(__GNUC__) && \
(defined(__x86_64__) || defined(__i386__) || defined(__arm__) || defined(__aarch64__))
// TLS register on x86 is in the FS or GS register, see: https://akkadia.org/drepper/tls.pdf
static inline void* mi_tls_slot(size_t slot) mi_attr_noexcept {
void* res;
const size_t ofs = (slot*sizeof(void*));
#if defined(__i386__)
__asm__("movl %%gs:%1, %0" : "=r" (res) : "m" (*((void**)ofs)) : ); // 32-bit always uses GS
#elif defined(__MACH__) && defined(__x86_64__)
__asm__("movq %%gs:%1, %0" : "=r" (res) : "m" (*((void**)ofs)) : ); // x86_64 macOSX uses GS
#elif defined(__x86_64__)
__asm__("movq %%fs:%1, %0" : "=r" (res) : "m" (*((void**)ofs)) : ); // x86_64 Linux, BSD uses FS
#elif defined(__arm__)
void** tcb; UNUSED(ofs);
__asm__ volatile ("mrc p15, 0, %0, c13, c0, 3\nbic %0, %0, #3" : "=r" (tcb));
res = tcb[slot];
#elif defined(__aarch64__)
void** tcb; UNUSED(ofs);
__asm__ volatile ("mrs %0, tpidr_el0" : "=r" (tcb));
res = tcb[slot];
#endif
return res;
}
// setting is only used on macOSX for now
static inline void mi_tls_slot_set(size_t slot, void* value) mi_attr_noexcept {
const size_t ofs = (slot*sizeof(void*));
#if defined(__i386__)
__asm__("movl %1,%%gs:%0" : "=m" (*((void**)ofs)) : "rn" (value) : ); // 32-bit always uses GS
#elif defined(__MACH__) && defined(__x86_64__)
__asm__("movq %1,%%gs:%0" : "=m" (*((void**)ofs)) : "rn" (value) : ); // x86_64 macOSX uses GS
#elif defined(__x86_64__)
__asm__("movq %1,%%fs:%1" : "=m" (*((void**)ofs)) : "rn" (value) : ); // x86_64 Linux, BSD uses FS
#elif defined(__arm__)
void** tcb; UNUSED(ofs);
__asm__ volatile ("mrc p15, 0, %0, c13, c0, 3\nbic %0, %0, #3" : "=r" (tcb));
tcb[slot] = value;
#elif defined(__aarch64__)
void** tcb; UNUSED(ofs);
__asm__ volatile ("mrs %0, tpidr_el0" : "=r" (tcb));
tcb[slot] = value;
#endif
}
static inline uintptr_t _mi_thread_id(void) mi_attr_noexcept {
// in all our targets, slot 0 is the pointer to the thread control block
return (uintptr_t)mi_tls_slot(0);
}
#else
// otherwise use standard C
static inline uintptr_t _mi_thread_id(void) mi_attr_noexcept {
return (uintptr_t)&_mi_heap_default;
}
#endif
// -----------------------------------------------------------------------
// Count bits: trailing or leading zeros (with MI_INTPTR_BITS on all zero)
// -----------------------------------------------------------------------
#if defined(__GNUC__)
#include <limits.h> // LONG_MAX
#define MI_HAVE_FAST_BITSCAN
static inline size_t mi_clz(uintptr_t x) {
if (x==0) return MI_INTPTR_BITS;
#if (INTPTR_MAX == LONG_MAX)
return __builtin_clzl(x);
#else
return __builtin_clzll(x);
#endif
}
static inline size_t mi_ctz(uintptr_t x) {
if (x==0) return MI_INTPTR_BITS;
#if (INTPTR_MAX == LONG_MAX)
return __builtin_ctzl(x);
#else
return __builtin_ctzll(x);
#endif
}
#elif defined(_MSC_VER)
#include <limits.h> // LONG_MAX
#define MI_HAVE_FAST_BITSCAN
static inline size_t mi_clz(uintptr_t x) {
if (x==0) return MI_INTPTR_BITS;
unsigned long idx;
#if (INTPTR_MAX == LONG_MAX)
_BitScanReverse(&idx, x);
#else
_BitScanReverse64(&idx, x);
#endif
return ((MI_INTPTR_BITS - 1) - idx);
}
static inline size_t mi_ctz(uintptr_t x) {
if (x==0) return MI_INTPTR_BITS;
unsigned long idx;
#if (INTPTR_MAX == LONG_MAX)
_BitScanForward(&idx, x);
#else
_BitScanForward64(&idx, x);
#endif
return idx;
}
#else
static inline size_t mi_ctz32(uint32_t x) {
// de Bruijn multiplication, see <http://supertech.csail.mit.edu/papers/debruijn.pdf>
static const unsigned char debruijn[32] = {
0, 1, 28, 2, 29, 14, 24, 3, 30, 22, 20, 15, 25, 17, 4, 8,
31, 27, 13, 23, 21, 19, 16, 7, 26, 12, 18, 6, 11, 5, 10, 9
};
if (x==0) return 32;
return debruijn[((x & -(int32_t)x) * 0x077CB531UL) >> 27];
}
static inline size_t mi_clz32(uint32_t x) {
// de Bruijn multiplication, see <http://supertech.csail.mit.edu/papers/debruijn.pdf>
static const uint8_t debruijn[32] = {
31, 22, 30, 21, 18, 10, 29, 2, 20, 17, 15, 13, 9, 6, 28, 1,
23, 19, 11, 3, 16, 14, 7, 24, 12, 4, 8, 25, 5, 26, 27, 0
};
if (x==0) return 32;
x |= x >> 1;
x |= x >> 2;
x |= x >> 4;
x |= x >> 8;
x |= x >> 16;
return debruijn[(uint32_t)(x * 0x07C4ACDDUL) >> 27];
}
static inline size_t mi_clz(uintptr_t x) {
if (x==0) return MI_INTPTR_BITS;
#if (MI_INTPTR_BITS <= 32)
return mi_clz32((uint32_t)x);
#else
size_t count = mi_clz32((uint32_t)(x >> 32));
if (count < 32) return count;
return (32 + mi_clz32((uint32_t)x));
#endif
}
static inline size_t mi_ctz(uintptr_t x) {
if (x==0) return MI_INTPTR_BITS;
#if (MI_INTPTR_BITS <= 32)
return mi_ctz32((uint32_t)x);
#else
size_t count = mi_ctz32((uint32_t)x);
if (count < 32) return count;
return (32 + mi_ctz32((uint32_t)(x>>32)));
#endif
}
#endif
// "bit scan reverse": Return index of the highest bit (or MI_INTPTR_BITS if `x` is zero)
static inline size_t mi_bsr(uintptr_t x) {
return (x==0 ? MI_INTPTR_BITS : MI_INTPTR_BITS - 1 - mi_clz(x));
}
#endif
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