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daan 2020-03-16 16:41:21 -07:00
commit 1f396e64a0
34 changed files with 2041 additions and 554 deletions
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222
include/mimalloc-internal.h
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@ -10,10 +10,6 @@ terms of the MIT license. A copy of the license can be found in the file
#include "mimalloc-types.h"
#if defined(MI_MALLOC_OVERRIDE) && (defined(__APPLE__) || defined(__OpenBSD__) || defined(__DragonFly__))
#define MI_TLS_RECURSE_GUARD
#endif
#if (MI_DEBUG>0)
#define mi_trace_message(...) _mi_trace_message(__VA_ARGS__)
#else
@ -33,7 +29,7 @@ terms of the MIT license. A copy of the license can be found in the file
#else
#define mi_decl_noinline
#define mi_decl_thread __thread // hope for the best :-)
#define mi_decl_cache_align
#define mi_decl_cache_align
#endif
@ -51,6 +47,7 @@ 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
@ -71,6 +68,7 @@ bool _mi_os_commit(void* addr, size_t size, bool* is_zero, mi_stats_t* stat
bool _mi_os_decommit(void* p, size_t size, mi_stats_t* stats);
bool _mi_os_reset(void* p, size_t size, mi_stats_t* stats);
bool _mi_os_unreset(void* p, size_t size, bool* is_zero, mi_stats_t* stats);
size_t _mi_os_good_alloc_size(size_t size);
// arena.c
void* _mi_arena_alloc_aligned(size_t size, size_t alignment, bool* commit, bool* large, bool* is_zero, size_t* memid, mi_os_tld_t* tld);
@ -89,6 +87,8 @@ uint8_t* _mi_segment_page_start(const mi_segment_t* segment, const mi_page_t*
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;
@ -238,9 +238,13 @@ static inline size_t _mi_wsize_from_size(size_t size) {
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
static inline bool mi_mul_overflow(size_t count, size_t size, size_t* total) {
static inline bool mi_mul_overflow(size_t count, size_t size, size_t* total) {
#if __has_builtin(__builtin_umul_overflow) || __GNUC__ >= 5
#include <limits.h> // UINT_MAX, ULONG_MAX
#if (SIZE_MAX == UINT_MAX)
@ -273,26 +277,76 @@ static inline bool mi_count_size_overflow(size_t count, size_t size, size_t* tot
}
/* -----------------------------------------------------------
The thread local default heap
----------------------------------------------------------- */
/* ----------------------------------------------------------------------------------------
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: not yet working.
------------------------------------------------------------------------------------------- */
extern const mi_heap_t _mi_heap_empty; // read-only empty heap, initial value of the thread local default heap
extern mi_heap_t _mi_heap_main; // statically allocated main backing 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) {
static 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) {
#ifdef MI_TLS_RECURSE_GUARD
// on some BSD platforms, like macOS, the dynamic loader calls `malloc`
// to initialize thread local data. To avoid recursion, we need to avoid
// accessing the thread local `_mi_default_heap` until our module is loaded
// and use the statically allocated main heap until that time.
// TODO: patch ourselves dynamically to avoid this check every time?
if (!_mi_process_is_initialized) return &_mi_heap_main;
#endif
#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) {
@ -309,6 +363,8 @@ static inline bool mi_heap_is_initialized(mi_heap_t* heap) {
}
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);
}
@ -317,8 +373,10 @@ static inline uintptr_t _mi_ptr_cookie(const void* p) {
----------------------------------------------------------- */
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);
return heap->pages_free_direct[_mi_wsize_from_size(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
@ -394,6 +452,13 @@ static inline size_t mi_page_block_size(const mi_page_t* page) {
}
}
// 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_read_relaxed(&page->xthread_free) & ~3);
@ -430,14 +495,14 @@ static inline mi_thread_free_t mi_tf_set_block(mi_thread_free_t tf, mi_block_t*
return mi_tf_make(block, mi_tf_delayed(tf));
}
// are all blocks in a page freed?
// 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?
// 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));
@ -485,11 +550,11 @@ static inline void mi_page_set_has_aligned(mi_page_t* page, bool 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`
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`).
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`).
@ -497,9 +562,9 @@ 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,
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
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.
@ -526,30 +591,37 @@ static inline uintptr_t mi_rotr(uintptr_t x, uintptr_t shift) {
return ((x >> shift) | (x << (MI_INTPTR_BITS - shift)));
}
static inline mi_block_t* mi_block_nextx( const void* null, const mi_block_t* block, uintptr_t key1, uintptr_t key2 ) {
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
mi_block_t* b = (mi_block_t*)(mi_rotr(block->next - key1, key1) ^ key2);
if (mi_unlikely((void*)b==null)) { b = NULL; }
return b;
return (mi_block_t*)mi_ptr_decode(null, block->next, keys);
#else
UNUSED(key1); UNUSED(key2); UNUSED(null);
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, uintptr_t key1, uintptr_t key2) {
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
if (mi_unlikely(next==NULL)) { next = (mi_block_t*)null; }
block->next = mi_rotl((uintptr_t)next ^ key2, key1) + key1;
block->next = mi_ptr_encode(null, next, keys);
#else
UNUSED(key1); UNUSED(key2); UNUSED(null);
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->key[0],page->key[1]);
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))) {
@ -559,16 +631,16 @@ static inline mi_block_t* mi_block_next(const mi_page_t* page, const mi_block_t*
return next;
#else
UNUSED(page);
return mi_block_nextx(page,block,0,0);
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->key[0], page->key[1]);
mi_block_set_nextx(page,block,next, page->keys);
#else
UNUSED(page);
mi_block_set_nextx(page,block, next,0,0);
mi_block_set_nextx(page,block,next,NULL);
#endif
}
@ -615,9 +687,8 @@ static inline size_t _mi_os_numa_node_count(void) {
// -------------------------------------------------------------------
// Getting the thread id should be performant
// as it is called in the fast path of `_mi_free`,
// so we specialize for various platforms.
// 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
@ -626,24 +697,55 @@ 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(__clang__)) && \
#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
// 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 {
uintptr_t tid;
#if defined(__i386__)
__asm__("movl %%gs:0, %0" : "=r" (tid) : : ); // 32-bit always uses GS
#elif defined(__MACH__)
__asm__("movq %%gs:0, %0" : "=r" (tid) : : ); // x86_64 macOS uses GS
#elif defined(__x86_64__)
__asm__("movq %%fs:0, %0" : "=r" (tid) : : ); // x86_64 Linux, BSD uses FS
#elif defined(__arm__)
asm volatile ("mrc p15, 0, %0, c13, c0, 3" : "=r" (tid));
#elif defined(__aarch64__)
asm volatile ("mrs %0, tpidr_el0" : "=r" (tid));
#endif
return tid;
// 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