/* ===---------- 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 <stdint.h>
#include <stdlib.h>
#include <string.h>
#include "int_lib.h"
#include "int_util.h"
typedef struct emutls_address_array {
uintptr_t size; /* number of elements in the 'data' array */
void* data[];
} emutls_address_array;
static void emutls_shutdown(emutls_address_array *array);
#ifndef _WIN32
#include <pthread.h>
static pthread_mutex_t emutls_mutex = PTHREAD_MUTEX_INITIALIZER;
static pthread_key_t emutls_pthread_key;
typedef unsigned int gcc_word __attribute__((mode(word)));
typedef unsigned int gcc_pointer __attribute__((mode(pointer)));
/* 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
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 = (char*)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
}
static void emutls_key_destructor(void* ptr) {
emutls_shutdown((emutls_address_array*)ptr);
free(ptr);
}
static __inline void emutls_init(void) {
if (pthread_key_create(&emutls_pthread_key, emutls_key_destructor) != 0)
abort();
}
static __inline void emutls_init_once(void) {
static pthread_once_t once = PTHREAD_ONCE_INIT;
pthread_once(&once, emutls_init);
}
static __inline void emutls_lock() {
pthread_mutex_lock(&emutls_mutex);
}
static __inline void emutls_unlock() {
pthread_mutex_unlock(&emutls_mutex);
}
static __inline void emutls_setspecific(emutls_address_array *value) {
pthread_setspecific(emutls_pthread_key, (void*) value);
}
static __inline emutls_address_array* emutls_getspecific() {
return (emutls_address_array*) pthread_getspecific(emutls_pthread_key);
}
#else
#include <windows.h>
#include <malloc.h>
#include <stdio.h>
#include <assert.h>
#include <immintrin.h>
static LPCRITICAL_SECTION emutls_mutex;
static DWORD emutls_tls_index = TLS_OUT_OF_INDEXES;
typedef uintptr_t gcc_word;
typedef void * gcc_pointer;
static void win_error(DWORD last_err, const char *hint) {
char *buffer = NULL;
if (FormatMessageA(FORMAT_MESSAGE_ALLOCATE_BUFFER |
FORMAT_MESSAGE_FROM_SYSTEM |
FORMAT_MESSAGE_MAX_WIDTH_MASK,
NULL, last_err, 0, (LPSTR)&buffer, 1, NULL)) {
fprintf(stderr, "Windows error: %s\n", buffer);
} else {
fprintf(stderr, "Unkown Windows error: %s\n", hint);
}
LocalFree(buffer);
}
static __inline void win_abort(DWORD last_err, const char *hint) {
win_error(last_err, hint);
abort();
}
static __inline void *emutls_memalign_alloc(size_t align, size_t size) {
void *base = _aligned_malloc(size, align);
if (!base)
win_abort(GetLastError(), "_aligned_malloc");
return base;
}
static __inline void emutls_memalign_free(void *base) {
_aligned_free(base);
}
static void emutls_exit(void) {
if (emutls_mutex) {
DeleteCriticalSection(emutls_mutex);
_aligned_free(emutls_mutex);
emutls_mutex = NULL;
}
if (emutls_tls_index != TLS_OUT_OF_INDEXES) {
emutls_shutdown((emutls_address_array*)TlsGetValue(emutls_tls_index));
TlsFree(emutls_tls_index);
emutls_tls_index = TLS_OUT_OF_INDEXES;
}
}
#pragma warning (push)
#pragma warning (disable : 4100)
static BOOL CALLBACK emutls_init(PINIT_ONCE p0, PVOID p1, PVOID *p2) {
emutls_mutex = (LPCRITICAL_SECTION)_aligned_malloc(sizeof(CRITICAL_SECTION), 16);
if (!emutls_mutex) {
win_error(GetLastError(), "_aligned_malloc");
return FALSE;
}
InitializeCriticalSection(emutls_mutex);
emutls_tls_index = TlsAlloc();
if (emutls_tls_index == TLS_OUT_OF_INDEXES) {
emutls_exit();
win_error(GetLastError(), "TlsAlloc");
return FALSE;
}
atexit(&emutls_exit);
return TRUE;
}
static __inline void emutls_init_once(void) {
static INIT_ONCE once;
InitOnceExecuteOnce(&once, emutls_init, NULL, NULL);
}
static __inline void emutls_lock() {
EnterCriticalSection(emutls_mutex);
}
static __inline void emutls_unlock() {
LeaveCriticalSection(emutls_mutex);
}
static __inline void emutls_setspecific(emutls_address_array *value) {
if (TlsSetValue(emutls_tls_index, (LPVOID) value) == 0)
win_abort(GetLastError(), "TlsSetValue");
}
static __inline emutls_address_array* emutls_getspecific() {
LPVOID value = TlsGetValue(emutls_tls_index);
if (value == NULL) {
const DWORD err = GetLastError();
if (err != ERROR_SUCCESS)
win_abort(err, "TlsGetValue");
}
return (emutls_address_array*) value;
}
/* Provide atomic load/store functions for emutls_get_index if built with MSVC.
*/
#if !defined(__ATOMIC_RELEASE)
enum { __ATOMIC_ACQUIRE = 2, __ATOMIC_RELEASE = 3 };
static __inline uintptr_t __atomic_load_n(void *ptr, unsigned type) {
assert(type == __ATOMIC_ACQUIRE);
#ifdef _WIN64
return (uintptr_t) _load_be_u64(ptr);
#else
return (uintptr_t) _load_be_u32(ptr);
#endif
}
static __inline void __atomic_store_n(void *ptr, uintptr_t val, unsigned type) {
assert(type == __ATOMIC_RELEASE);
#ifdef _WIN64
_store_be_u64(ptr, val);
#else
_store_be_u32(ptr, val);
#endif
}
#endif
#pragma warning (pop)
#endif
static size_t emutls_num_object = 0; /* number of allocated TLS objects */
/* Free the allocated TLS data
*/
static void emutls_shutdown(emutls_address_array *array) {
if (array) {
uintptr_t i;
for (i = 0; i < array->size; ++i) {
if (array->data[i])
emutls_memalign_free(array->data[i]);
}
}
}
/* 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 {
/* Must use gcc_word here, instead of size_t, to match GCC. When
gcc_word is larger than size_t, the upper extra bits are all
zeros. We can use variables of size_t to operate on size and
align. */
gcc_word size; /* size of the object in bytes */
gcc_word 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;
/* 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. */
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;
void* base;
if (align < sizeof(void*))
align = sizeof(void*);
/* Make sure that align is power of 2. */
if ((align & (align - 1)) != 0)
abort();
base = emutls_memalign_alloc(align, size);
if (control->value)
memcpy(base, control->value, size);
else
memset(base, 0, size);
return base;
}
/* 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) {
emutls_init_once();
emutls_lock();
index = control->object.index;
if (!index) {
index = ++emutls_num_object;
__atomic_store_n(&control->object.index, index, __ATOMIC_RELEASE);
}
emutls_unlock();
}
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;
emutls_setspecific(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 size in bytes required for an emutls_address_array with
* N number of elements for data field.
*/
static __inline uintptr_t emutls_asize(uintptr_t N) {
return N * sizeof(void *) + sizeof(emutls_address_array);
}
/* 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 = emutls_getspecific();
if (array == NULL) {
uintptr_t new_size = emutls_new_data_array_size(index);
array = (emutls_address_array*) malloc(emutls_asize(new_size));
if (array)
memset(array->data, 0, new_size * 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 = (emutls_address_array*) realloc(array, emutls_asize(new_size));
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] == NULL)
array->data[index] = emutls_allocate_object(control);
return array->data[index];
}
