2 changed files with 184 additions and 1 deletions
@ -0,0 +1,181 @@ |
|||||
|
/* ===---------- emutls.c - Implements __emutls_get_address ---------------=== |
||||
|
* |
||||
|
* The LLVM Compiler Infrastructure |
||||
|
* |
||||
|
* This file is dual licensed under the MIT and the University of Illinois Open |
||||
|
* Source Licenses. See LICENSE.TXT for details. |
||||
|
* |
||||
|
* ===----------------------------------------------------------------------=== |
||||
|
*/ |
||||
|
#include <pthread.h> |
||||
|
#include <stdint.h> |
||||
|
#include <stdlib.h> |
||||
|
#include <string.h> |
||||
|
|
||||
|
//#include "int_util.h" |
||||
|
|
||||
|
/* Default is not to use posix_memalign, so systems like Android |
||||
|
* can use thread local data without heavier POSIX memory allocators. |
||||
|
*/ |
||||
|
#ifndef EMUTLS_USE_POSIX_MEMALIGN |
||||
|
#define EMUTLS_USE_POSIX_MEMALIGN 0 |
||||
|
#endif |
||||
|
|
||||
|
/* For every TLS variable xyz, |
||||
|
* there is one __emutls_control variable named __emutls_v.xyz. |
||||
|
* If xyz has non-zero initial value, __emutls_v.xyz's "value" |
||||
|
* will point to __emutls_t.xyz, which has the initial value. |
||||
|
*/ |
||||
|
typedef struct __emutls_control { |
||||
|
size_t size; /* size of the object in bytes */ |
||||
|
size_t align; /* alignment of the object in bytes */ |
||||
|
union { |
||||
|
uintptr_t index; /* data[index-1] is the object address */ |
||||
|
void* address; /* object address, when in single thread env */ |
||||
|
} object; |
||||
|
void* value; /* null or non-zero initial value for the object */ |
||||
|
} __emutls_control; |
||||
|
|
||||
|
static inline void* emutls_memalign_alloc(size_t align, size_t size) { |
||||
|
void *base; |
||||
|
#if EMUTLS_USE_POSIX_MEMALIGN |
||||
|
if (posix_memalign(&base, align, size) != 0) |
||||
|
abort(); |
||||
|
#else |
||||
|
#define EXTRA_ALIGN_PTR_BYTES (align - 1 + sizeof(void*)) |
||||
|
char* object; |
||||
|
if ((object = malloc(EXTRA_ALIGN_PTR_BYTES + size)) == NULL) |
||||
|
abort(); |
||||
|
base = (void*)(((uintptr_t)(object + EXTRA_ALIGN_PTR_BYTES)) |
||||
|
& ~(uintptr_t)(align - 1)); |
||||
|
|
||||
|
((void**)base)[-1] = object; |
||||
|
#endif |
||||
|
return base; |
||||
|
} |
||||
|
|
||||
|
static inline void emutls_memalign_free(void* base) { |
||||
|
#if EMUTLS_USE_POSIX_MEMALIGN |
||||
|
free(base); |
||||
|
#else |
||||
|
/* The mallocated address is in ((void**)base)[-1] */ |
||||
|
free(((void**)base)[-1]); |
||||
|
#endif |
||||
|
} |
||||
|
|
||||
|
/* Emulated TLS objects are always allocated at run-time. */ |
||||
|
static inline void* emutls_allocate_object(__emutls_control* control) { |
||||
|
/* Use standard C types, check with gcc's emutls.o. */ |
||||
|
//typedef unsigned int gcc_word __attribute__((mode(word))); |
||||
|
//typedef unsigned int gcc_pointer __attribute__((mode(pointer))); |
||||
|
//COMPILE_TIME_ASSERT(sizeof(size_t) == sizeof(gcc_word)); |
||||
|
//COMPILE_TIME_ASSERT(sizeof(uintptr_t) == sizeof(gcc_pointer)); |
||||
|
//COMPILE_TIME_ASSERT(sizeof(uintptr_t) == sizeof(void*)); |
||||
|
|
||||
|
size_t size = control->size; |
||||
|
size_t align = control->align; |
||||
|
if (align < sizeof(void*)) |
||||
|
align = sizeof(void*); |
||||
|
/* Make sure that align is power of 2. */ |
||||
|
if ((align & (align - 1)) != 0) |
||||
|
abort(); |
||||
|
|
||||
|
void* base = emutls_memalign_alloc(align, size); |
||||
|
if (control->value) |
||||
|
memcpy(base, control->value, size); |
||||
|
else |
||||
|
memset(base, 0, size); |
||||
|
return base; |
||||
|
} |
||||
|
|
||||
|
static pthread_mutex_t emutls_mutex = PTHREAD_MUTEX_INITIALIZER; |
||||
|
|
||||
|
static size_t emutls_num_object = 0; /* number of allocated TLS objects */ |
||||
|
|
||||
|
typedef struct emutls_address_array { |
||||
|
uintptr_t size; /* number of elements in the 'data' array */ |
||||
|
void* data[]; |
||||
|
} emutls_address_array; |
||||
|
|
||||
|
static pthread_key_t emutls_pthread_key; |
||||
|
|
||||
|
static void emutls_key_destructor(void* ptr) { |
||||
|
emutls_address_array* array = (emutls_address_array*)ptr; |
||||
|
uintptr_t i; |
||||
|
for (i = 0; i < array->size; ++i) { |
||||
|
if (array->data[i]) |
||||
|
emutls_memalign_free(array->data[i]); |
||||
|
} |
||||
|
free(ptr); |
||||
|
} |
||||
|
|
||||
|
static void emutls_init(void) { |
||||
|
if (pthread_key_create(&emutls_pthread_key, emutls_key_destructor) != 0) |
||||
|
abort(); |
||||
|
} |
||||
|
|
||||
|
/* Returns control->object.index; set index if not allocated yet. */ |
||||
|
static inline uintptr_t emutls_get_index(__emutls_control* control) { |
||||
|
uintptr_t index = __atomic_load_n(&control->object.index, __ATOMIC_ACQUIRE); |
||||
|
if (!index) { |
||||
|
static pthread_once_t once = PTHREAD_ONCE_INIT; |
||||
|
pthread_once(&once, emutls_init); |
||||
|
pthread_mutex_lock(&emutls_mutex); |
||||
|
index = control->object.index; |
||||
|
if (!index) { |
||||
|
index = ++emutls_num_object; |
||||
|
__atomic_store_n(&control->object.index, index, __ATOMIC_RELEASE); |
||||
|
} |
||||
|
pthread_mutex_unlock(&emutls_mutex); |
||||
|
} |
||||
|
return index; |
||||
|
} |
||||
|
|
||||
|
/* Updates newly allocated thread local emutls_address_array. */ |
||||
|
static inline void emutls_check_array_set_size(emutls_address_array* array, |
||||
|
uintptr_t size) { |
||||
|
if (array == NULL) |
||||
|
abort(); |
||||
|
array->size = size; |
||||
|
pthread_setspecific(emutls_pthread_key, (void*)array); |
||||
|
} |
||||
|
|
||||
|
/* Returns the new 'data' array size, number of elements, |
||||
|
* which must be no smaller than the given index. |
||||
|
*/ |
||||
|
static inline uintptr_t emutls_new_data_array_size(uintptr_t index) { |
||||
|
/* Need to allocate emutls_address_array with one extra slot |
||||
|
* to store the data array size. |
||||
|
* Round up the emutls_address_array size to multiple of 16. |
||||
|
*/ |
||||
|
return ((index + 1 + 15) & ~((uintptr_t)15)) - 1; |
||||
|
} |
||||
|
|
||||
|
/* Returns the thread local emutls_address_array. |
||||
|
* Extends its size if necessary to hold address at index. |
||||
|
*/ |
||||
|
static inline emutls_address_array* emutls_get_address_array(uintptr_t index) { |
||||
|
emutls_address_array* array = pthread_getspecific(emutls_pthread_key); |
||||
|
if (array == NULL) { |
||||
|
uintptr_t new_size = emutls_new_data_array_size(index); |
||||
|
array = calloc(new_size + 1, sizeof(void*)); |
||||
|
emutls_check_array_set_size(array, new_size); |
||||
|
} else if (index > array->size) { |
||||
|
uintptr_t orig_size = array->size; |
||||
|
uintptr_t new_size = emutls_new_data_array_size(index); |
||||
|
array = realloc(array, (new_size + 1) * sizeof(void*)); |
||||
|
if (array) |
||||
|
memset(array->data + orig_size, 0, |
||||
|
(new_size - orig_size) * sizeof(void*)); |
||||
|
emutls_check_array_set_size(array, new_size); |
||||
|
} |
||||
|
return array; |
||||
|
} |
||||
|
|
||||
|
void* __emutls_get_address(__emutls_control* control) { |
||||
|
uintptr_t index = emutls_get_index(control); |
||||
|
emutls_address_array* array = emutls_get_address_array(index); |
||||
|
if (array->data[index - 1] == NULL) |
||||
|
array->data[index - 1] = emutls_allocate_object(control); |
||||
|
return array->data[index - 1]; |
||||
|
} |
||||
Write
Preview
Loading…
Cancel
Save
Reference in new issue