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Diffstat (limited to 'components/libc/cplusplus/cpp11/emutls.c')
| -rw-r--r-- | components/libc/cplusplus/cpp11/emutls.c | 216 |
1 files changed, 216 insertions, 0 deletions
diff --git a/components/libc/cplusplus/cpp11/emutls.c b/components/libc/cplusplus/cpp11/emutls.c new file mode 100644 index 0000000000..576888f16f --- /dev/null +++ b/components/libc/cplusplus/cpp11/emutls.c @@ -0,0 +1,216 @@ +/* + * Copyright (c) 2006-2021, RT-Thread Development Team + * + * SPDX-License-Identifier: Apache-2.0 + * + * Change Logs: + * Date Author Notes + * 2021-04-27 peterfan Add copyright header. + */ + +/* ===---------- 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> + +#define COMPILE_TIME_ASSERT(x) + +extern int pthread_key_create(pthread_key_t *key, void (*destructor)(void *)); +extern int pthread_key_delete(pthread_key_t key); +extern void *pthread_getspecific(pthread_key_t key); +extern int pthread_setspecific(pthread_key_t key, const void *value); + +/* 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(void *control) +{ + uintptr_t index = emutls_get_index((__emutls_control *)control); + emutls_address_array *array = emutls_get_address_array(index); + if (array->data[index - 1] == NULL) + array->data[index - 1] = emutls_allocate_object((__emutls_control *)control); + return array->data[index - 1]; +} |