src/sljit/sljitUtils.c - platform/external/pcre - Gitiles

 /*
  *    Stack-less Just-In-Time compiler
  *
  *    Copyright Zoltan Herczeg (hzmester@freemail.hu). All rights reserved.
  *
  * Redistribution and use in source and binary forms, with or without modification, are
  * permitted provided that the following conditions are met:
  *
  *   1. Redistributions of source code must retain the above copyright notice, this list of
  *      conditions and the following disclaimer.
  *
  *   2. Redistributions in binary form must reproduce the above copyright notice, this list
  *      of conditions and the following disclaimer in the documentation and/or other materials
  *      provided with the distribution.
  *
  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) AND CONTRIBUTORS ``AS IS'' AND ANY
  * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
  * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
  * SHALL THE COPYRIGHT HOLDER(S) OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
  * TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
  * BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
  * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */

 /* ------------------------------------------------------------------------ */
 /*  Locks                                                                   */
 /* ------------------------------------------------------------------------ */

 /* Executable Allocator */

 #if (defined SLJIT_EXECUTABLE_ALLOCATOR && SLJIT_EXECUTABLE_ALLOCATOR) \
 	&& !(defined SLJIT_WX_EXECUTABLE_ALLOCATOR && SLJIT_WX_EXECUTABLE_ALLOCATOR)
 #if (defined SLJIT_SINGLE_THREADED && SLJIT_SINGLE_THREADED)
 #define SLJIT_ALLOCATOR_LOCK()
 #define SLJIT_ALLOCATOR_UNLOCK()
 #elif !(defined _WIN32)
 #include <pthread.h>

 static pthread_mutex_t allocator_lock = PTHREAD_MUTEX_INITIALIZER;

 #define SLJIT_ALLOCATOR_LOCK() pthread_mutex_lock(&allocator_lock)
 #define SLJIT_ALLOCATOR_UNLOCK() pthread_mutex_unlock(&allocator_lock)
 #else /* windows */
 static HANDLE allocator_lock;

 static SLJIT_INLINE void allocator_grab_lock(void)
 {
 	HANDLE lock;
 	if (SLJIT_UNLIKELY(!InterlockedCompareExchangePointer(&allocator_lock, NULL, NULL))) {
 		lock = CreateMutex(NULL, FALSE, NULL);
 		if (InterlockedCompareExchangePointer(&allocator_lock, lock, NULL))
 			CloseHandle(lock);
 	}
 	WaitForSingleObject(allocator_lock, INFINITE);
 }

 #define SLJIT_ALLOCATOR_LOCK() allocator_grab_lock()
 #define SLJIT_ALLOCATOR_UNLOCK() ReleaseMutex(allocator_lock)
 #endif /* thread implementation */
 #endif /* SLJIT_EXECUTABLE_ALLOCATOR && !SLJIT_WX_EXECUTABLE_ALLOCATOR */

 /* ------------------------------------------------------------------------ */
 /*  Stack                                                                   */
 /* ------------------------------------------------------------------------ */

 #if ((defined SLJIT_UTIL_STACK && SLJIT_UTIL_STACK) \
 	&& !(defined SLJIT_UTIL_SIMPLE_STACK_ALLOCATION && SLJIT_UTIL_SIMPLE_STACK_ALLOCATION)) \
 	|| ((defined SLJIT_EXECUTABLE_ALLOCATOR && SLJIT_EXECUTABLE_ALLOCATOR) \
 	&& !((defined SLJIT_PROT_EXECUTABLE_ALLOCATOR && SLJIT_PROT_EXECUTABLE_ALLOCATOR) \
 	|| (defined SLJIT_WX_EXECUTABLE_ALLOCATOR && SLJIT_WX_EXECUTABLE_ALLOCATOR)))

 #ifndef _WIN32
 /* Provides mmap function. */
 #include <sys/types.h>
 #include <sys/mman.h>

 #ifndef MAP_ANON
 #ifdef MAP_ANONYMOUS
 #define MAP_ANON MAP_ANONYMOUS
 #endif /* MAP_ANONYMOUS */
 #endif /* !MAP_ANON */

 #ifndef MAP_ANON

 #include <fcntl.h>

 #ifdef O_CLOEXEC
 #define SLJIT_CLOEXEC	O_CLOEXEC
 #else /* !O_CLOEXEC */
 #define SLJIT_CLOEXEC	0
 #endif /* O_CLOEXEC */

 /* Some old systems do not have MAP_ANON. */
 static int dev_zero = -1;

 #if (defined SLJIT_SINGLE_THREADED && SLJIT_SINGLE_THREADED)

 static SLJIT_INLINE int open_dev_zero(void)
 {
 	dev_zero = open("/dev/zero", O_RDWR | SLJIT_CLOEXEC);

 	return dev_zero < 0;
 }

 #else /* !SLJIT_SINGLE_THREADED */

 #include <pthread.h>

 static pthread_mutex_t dev_zero_mutex = PTHREAD_MUTEX_INITIALIZER;

 static SLJIT_INLINE int open_dev_zero(void)
 {
 	pthread_mutex_lock(&dev_zero_mutex);
 	if (SLJIT_UNLIKELY(dev_zero < 0))
 		dev_zero = open("/dev/zero", O_RDWR | SLJIT_CLOEXEC);

 	pthread_mutex_unlock(&dev_zero_mutex);
 	return dev_zero < 0;
 }

 #endif /* SLJIT_SINGLE_THREADED */
 #undef SLJIT_CLOEXEC
 #endif /* !MAP_ANON */
 #endif /* !_WIN32 */
 #endif /* open_dev_zero */

 #if (defined SLJIT_UTIL_STACK && SLJIT_UTIL_STACK) \
 	|| (defined SLJIT_EXECUTABLE_ALLOCATOR && SLJIT_EXECUTABLE_ALLOCATOR)

 #ifdef _WIN32

 static SLJIT_INLINE sljit_sw get_page_alignment(void) {
 	SYSTEM_INFO si;
 	static sljit_sw sljit_page_align;
 	if (!sljit_page_align) {
 		GetSystemInfo(&si);
 		sljit_page_align = si.dwPageSize - 1;
 	}
 	return sljit_page_align;
 }

 #else

 #include <unistd.h>

 static SLJIT_INLINE sljit_sw get_page_alignment(void) {
 	static sljit_sw sljit_page_align = -1;
 	if (sljit_page_align < 0) {
 #ifdef _SC_PAGESIZE
 		sljit_page_align = sysconf(_SC_PAGESIZE);
 #else
 		sljit_page_align = getpagesize();
 #endif
 		/* Should never happen. */
 		if (sljit_page_align < 0)
 			sljit_page_align = 4096;
 		sljit_page_align--;
 	}
 	return sljit_page_align;
 }

 #endif /* _WIN32 */

 #endif /* get_page_alignment() */

 #if (defined SLJIT_UTIL_STACK && SLJIT_UTIL_STACK)

 #if (defined SLJIT_UTIL_SIMPLE_STACK_ALLOCATION && SLJIT_UTIL_SIMPLE_STACK_ALLOCATION)

 SLJIT_API_FUNC_ATTRIBUTE struct sljit_stack* SLJIT_FUNC sljit_allocate_stack(sljit_uw start_size, sljit_uw max_size, void *allocator_data)
 {
 	struct sljit_stack *stack;
 	void *ptr;

 	SLJIT_UNUSED_ARG(allocator_data);

 	if (start_size > max_size || start_size < 1)
 		return NULL;

 	stack = (struct sljit_stack*)SLJIT_MALLOC(sizeof(struct sljit_stack), allocator_data);
 	if (stack == NULL)
 		return NULL;

 	ptr = SLJIT_MALLOC(max_size, allocator_data);
 	if (ptr == NULL) {
 		SLJIT_FREE(stack, allocator_data);
 		return NULL;
 	}

 	stack->min_start = (sljit_u8 *)ptr;
  	stack->end = stack->min_start + max_size;
  	stack->start = stack->end - start_size;
 	stack->top = stack->end;
 	return stack;
 }

 SLJIT_API_FUNC_ATTRIBUTE void SLJIT_FUNC sljit_free_stack(struct sljit_stack *stack, void *allocator_data)
 {
 	SLJIT_UNUSED_ARG(allocator_data);
 	SLJIT_FREE((void*)stack->min_start, allocator_data);
 	SLJIT_FREE(stack, allocator_data);
 }

 SLJIT_API_FUNC_ATTRIBUTE sljit_u8 *SLJIT_FUNC sljit_stack_resize(struct sljit_stack *stack, sljit_u8 *new_start)
 {
 	if ((new_start < stack->min_start) || (new_start >= stack->end))
 		return NULL;
 	stack->start = new_start;
 	return new_start;
 }

 #else /* !SLJIT_UTIL_SIMPLE_STACK_ALLOCATION */

 #ifdef _WIN32

 SLJIT_API_FUNC_ATTRIBUTE void SLJIT_FUNC sljit_free_stack(struct sljit_stack *stack, void *allocator_data)
 {
 	SLJIT_UNUSED_ARG(allocator_data);
 	VirtualFree((void*)stack->min_start, 0, MEM_RELEASE);
 	SLJIT_FREE(stack, allocator_data);
 }

 #else /* !_WIN32 */

 SLJIT_API_FUNC_ATTRIBUTE void SLJIT_FUNC sljit_free_stack(struct sljit_stack *stack, void *allocator_data)
 {
 	SLJIT_UNUSED_ARG(allocator_data);
 	munmap((void*)stack->min_start, stack->end - stack->min_start);
 	SLJIT_FREE(stack, allocator_data);
 }

 #endif /* _WIN32 */

 SLJIT_API_FUNC_ATTRIBUTE struct sljit_stack* SLJIT_FUNC sljit_allocate_stack(sljit_uw start_size, sljit_uw max_size, void *allocator_data)
 {
 	struct sljit_stack *stack;
 	void *ptr;
 	sljit_sw page_align;

 	SLJIT_UNUSED_ARG(allocator_data);

 	if (start_size > max_size || start_size < 1)
 		return NULL;

 	stack = (struct sljit_stack*)SLJIT_MALLOC(sizeof(struct sljit_stack), allocator_data);
 	if (stack == NULL)
 		return NULL;

 	/* Align max_size. */
 	page_align = get_page_alignment();
 	max_size = (max_size + page_align) & ~page_align;

 #ifdef _WIN32
 	ptr = VirtualAlloc(NULL, max_size, MEM_RESERVE, PAGE_READWRITE);
 	if (!ptr) {
 		SLJIT_FREE(stack, allocator_data);
 		return NULL;
 	}

 	stack->min_start = (sljit_u8 *)ptr;
 	stack->end = stack->min_start + max_size;
 	stack->start = stack->end;

 	if (sljit_stack_resize(stack, stack->end - start_size) == NULL) {
 		sljit_free_stack(stack, allocator_data);
 		return NULL;
 	}
 #else /* !_WIN32 */
 #ifdef MAP_ANON
 	ptr = mmap(NULL, max_size, PROT_READ | PROT_WRITE, MAP_PRIVATE | MAP_ANON, -1, 0);
 #else /* !MAP_ANON */
 	if (SLJIT_UNLIKELY((dev_zero < 0) && open_dev_zero())) {
 		SLJIT_FREE(stack, allocator_data);
 		return NULL;
 	}
 	ptr = mmap(NULL, max_size, PROT_READ | PROT_WRITE, MAP_PRIVATE, dev_zero, 0);
 #endif /* MAP_ANON */
 	if (ptr == MAP_FAILED) {
 		SLJIT_FREE(stack, allocator_data);
 		return NULL;
 	}
 	stack->min_start = (sljit_u8 *)ptr;
 	stack->end = stack->min_start + max_size;
 	stack->start = stack->end - start_size;
 #endif /* _WIN32 */

 	stack->top = stack->end;
 	return stack;
 }

 SLJIT_API_FUNC_ATTRIBUTE sljit_u8 *SLJIT_FUNC sljit_stack_resize(struct sljit_stack *stack, sljit_u8 *new_start)
 {
 #if defined _WIN32 || defined(POSIX_MADV_DONTNEED)
 	sljit_uw aligned_old_start;
 	sljit_uw aligned_new_start;
 	sljit_sw page_align;
 #endif

 	if ((new_start < stack->min_start) || (new_start >= stack->end))
 		return NULL;

 #ifdef _WIN32
 	page_align = get_page_alignment();

 	aligned_new_start = (sljit_uw)new_start & ~page_align;
 	aligned_old_start = ((sljit_uw)stack->start) & ~page_align;
 	if (aligned_new_start != aligned_old_start) {
 		if (aligned_new_start < aligned_old_start) {
 			if (!VirtualAlloc((void*)aligned_new_start, aligned_old_start - aligned_new_start, MEM_COMMIT, PAGE_READWRITE))
 				return NULL;
 		}
 		else {
 			if (!VirtualFree((void*)aligned_old_start, aligned_new_start - aligned_old_start, MEM_DECOMMIT))
 				return NULL;
 		}
 	}
 #elif defined(POSIX_MADV_DONTNEED)
 	if (stack->start < new_start) {
 		page_align = get_page_alignment();

 		aligned_new_start = (sljit_uw)new_start & ~page_align;
 		aligned_old_start = ((sljit_uw)stack->start) & ~page_align;

 		if (aligned_new_start > aligned_old_start) {
 			posix_madvise((void*)aligned_old_start, aligned_new_start - aligned_old_start, POSIX_MADV_DONTNEED);
 #ifdef MADV_FREE
 			madvise((void*)aligned_old_start, aligned_new_start - aligned_old_start, MADV_FREE);
 #endif /* MADV_FREE */
 		}
 	}
 #endif /* _WIN32 */

 	stack->start = new_start;
 	return new_start;
 }

 #endif /* SLJIT_UTIL_SIMPLE_STACK_ALLOCATION */

 #endif /* SLJIT_UTIL_STACK */
	/*
	* Stack-less Just-In-Time compiler
	*
	* Copyright Zoltan Herczeg (hzmester@freemail.hu). All rights reserved.
	*
	* Redistribution and use in source and binary forms, with or without modification, are
	* permitted provided that the following conditions are met:
	*
	* 1. Redistributions of source code must retain the above copyright notice, this list of
	* conditions and the following disclaimer.
	*
	* 2. Redistributions in binary form must reproduce the above copyright notice, this list
	* of conditions and the following disclaimer in the documentation and/or other materials
	* provided with the distribution.
	*
	* THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDER(S) AND CONTRIBUTORS ``AS IS'' AND ANY
	* EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT
	* SHALL THE COPYRIGHT HOLDER(S) OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED
	* TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR
	* BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
	* CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
	* ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
	*/

	/* ------------------------------------------------------------------------ */
	/* Locks */
	/* ------------------------------------------------------------------------ */

	/* Executable Allocator */

	#if (defined SLJIT_EXECUTABLE_ALLOCATOR && SLJIT_EXECUTABLE_ALLOCATOR) \
	&& !(defined SLJIT_WX_EXECUTABLE_ALLOCATOR && SLJIT_WX_EXECUTABLE_ALLOCATOR)
	#if (defined SLJIT_SINGLE_THREADED && SLJIT_SINGLE_THREADED)
	#define SLJIT_ALLOCATOR_LOCK()
	#define SLJIT_ALLOCATOR_UNLOCK()
	#elif !(defined _WIN32)
	#include <pthread.h>

	static pthread_mutex_t allocator_lock = PTHREAD_MUTEX_INITIALIZER;

	#define SLJIT_ALLOCATOR_LOCK() pthread_mutex_lock(&allocator_lock)
	#define SLJIT_ALLOCATOR_UNLOCK() pthread_mutex_unlock(&allocator_lock)
	#else /* windows */
	static HANDLE allocator_lock;

	static SLJIT_INLINE void allocator_grab_lock(void)
	{
	HANDLE lock;
	if (SLJIT_UNLIKELY(!InterlockedCompareExchangePointer(&allocator_lock, NULL, NULL))) {
	lock = CreateMutex(NULL, FALSE, NULL);
	if (InterlockedCompareExchangePointer(&allocator_lock, lock, NULL))
	CloseHandle(lock);
	}
	WaitForSingleObject(allocator_lock, INFINITE);
	}

	#define SLJIT_ALLOCATOR_LOCK() allocator_grab_lock()
	#define SLJIT_ALLOCATOR_UNLOCK() ReleaseMutex(allocator_lock)
	#endif /* thread implementation */
	#endif /* SLJIT_EXECUTABLE_ALLOCATOR && !SLJIT_WX_EXECUTABLE_ALLOCATOR */

	/* ------------------------------------------------------------------------ */
	/* Stack */
	/* ------------------------------------------------------------------------ */

	#if ((defined SLJIT_UTIL_STACK && SLJIT_UTIL_STACK) \
	&& !(defined SLJIT_UTIL_SIMPLE_STACK_ALLOCATION && SLJIT_UTIL_SIMPLE_STACK_ALLOCATION)) \
	\|\| ((defined SLJIT_EXECUTABLE_ALLOCATOR && SLJIT_EXECUTABLE_ALLOCATOR) \
	&& !((defined SLJIT_PROT_EXECUTABLE_ALLOCATOR && SLJIT_PROT_EXECUTABLE_ALLOCATOR) \
	\|\| (defined SLJIT_WX_EXECUTABLE_ALLOCATOR && SLJIT_WX_EXECUTABLE_ALLOCATOR)))

	#ifndef _WIN32
	/* Provides mmap function. */
	#include <sys/types.h>
	#include <sys/mman.h>

	#ifndef MAP_ANON
	#ifdef MAP_ANONYMOUS
	#define MAP_ANON MAP_ANONYMOUS
	#endif /* MAP_ANONYMOUS */
	#endif /* !MAP_ANON */

	#ifndef MAP_ANON

	#include <fcntl.h>

	#ifdef O_CLOEXEC
	#define SLJIT_CLOEXEC O_CLOEXEC
	#else /* !O_CLOEXEC */
	#define SLJIT_CLOEXEC 0
	#endif /* O_CLOEXEC */

	/* Some old systems do not have MAP_ANON. */
	static int dev_zero = -1;

	#if (defined SLJIT_SINGLE_THREADED && SLJIT_SINGLE_THREADED)

	static SLJIT_INLINE int open_dev_zero(void)
	{
	dev_zero = open("/dev/zero", O_RDWR \| SLJIT_CLOEXEC);

	return dev_zero < 0;
	}

	#else /* !SLJIT_SINGLE_THREADED */

	#include <pthread.h>

	static pthread_mutex_t dev_zero_mutex = PTHREAD_MUTEX_INITIALIZER;

	static SLJIT_INLINE int open_dev_zero(void)
	{
	pthread_mutex_lock(&dev_zero_mutex);
	if (SLJIT_UNLIKELY(dev_zero < 0))
	dev_zero = open("/dev/zero", O_RDWR \| SLJIT_CLOEXEC);

	pthread_mutex_unlock(&dev_zero_mutex);
	return dev_zero < 0;
	}

	#endif /* SLJIT_SINGLE_THREADED */
	#undef SLJIT_CLOEXEC
	#endif /* !MAP_ANON */
	#endif /* !_WIN32 */
	#endif /* open_dev_zero */

	#if (defined SLJIT_UTIL_STACK && SLJIT_UTIL_STACK) \
	\|\| (defined SLJIT_EXECUTABLE_ALLOCATOR && SLJIT_EXECUTABLE_ALLOCATOR)

	#ifdef _WIN32

	static SLJIT_INLINE sljit_sw get_page_alignment(void) {
	SYSTEM_INFO si;
	static sljit_sw sljit_page_align;
	if (!sljit_page_align) {
	GetSystemInfo(&si);
	sljit_page_align = si.dwPageSize - 1;
	}
	return sljit_page_align;
	}

	#else

	#include <unistd.h>

	static SLJIT_INLINE sljit_sw get_page_alignment(void) {
	static sljit_sw sljit_page_align = -1;
	if (sljit_page_align < 0) {
	#ifdef _SC_PAGESIZE
	sljit_page_align = sysconf(_SC_PAGESIZE);
	#else
	sljit_page_align = getpagesize();
	#endif
	/* Should never happen. */
	if (sljit_page_align < 0)
	sljit_page_align = 4096;
	sljit_page_align--;
	}
	return sljit_page_align;
	}

	#endif /* _WIN32 */

	#endif /* get_page_alignment() */

	#if (defined SLJIT_UTIL_STACK && SLJIT_UTIL_STACK)

	#if (defined SLJIT_UTIL_SIMPLE_STACK_ALLOCATION && SLJIT_UTIL_SIMPLE_STACK_ALLOCATION)

	SLJIT_API_FUNC_ATTRIBUTE struct sljit_stack* SLJIT_FUNC sljit_allocate_stack(sljit_uw start_size, sljit_uw max_size, void *allocator_data)
	{
	struct sljit_stack *stack;
	void *ptr;

	SLJIT_UNUSED_ARG(allocator_data);

	if (start_size > max_size \|\| start_size < 1)
	return NULL;

	stack = (struct sljit_stack*)SLJIT_MALLOC(sizeof(struct sljit_stack), allocator_data);
	if (stack == NULL)
	return NULL;

	ptr = SLJIT_MALLOC(max_size, allocator_data);
	if (ptr == NULL) {
	SLJIT_FREE(stack, allocator_data);
	return NULL;
	}

	stack->min_start = (sljit_u8 *)ptr;
	stack->end = stack->min_start + max_size;
	stack->start = stack->end - start_size;
	stack->top = stack->end;
	return stack;
	}

	SLJIT_API_FUNC_ATTRIBUTE void SLJIT_FUNC sljit_free_stack(struct sljit_stack stack, void allocator_data)
	{
	SLJIT_UNUSED_ARG(allocator_data);
	SLJIT_FREE((void*)stack->min_start, allocator_data);
	SLJIT_FREE(stack, allocator_data);
	}

	SLJIT_API_FUNC_ATTRIBUTE sljit_u8 SLJIT_FUNC sljit_stack_resize(struct sljit_stack stack, sljit_u8 *new_start)
	{
	if ((new_start < stack->min_start) \|\| (new_start >= stack->end))
	return NULL;
	stack->start = new_start;
	return new_start;
	}

	#else /* !SLJIT_UTIL_SIMPLE_STACK_ALLOCATION */

	#ifdef _WIN32

	SLJIT_API_FUNC_ATTRIBUTE void SLJIT_FUNC sljit_free_stack(struct sljit_stack stack, void allocator_data)
	{
	SLJIT_UNUSED_ARG(allocator_data);
	VirtualFree((void*)stack->min_start, 0, MEM_RELEASE);
	SLJIT_FREE(stack, allocator_data);
	}

	#else /* !_WIN32 */

	SLJIT_API_FUNC_ATTRIBUTE void SLJIT_FUNC sljit_free_stack(struct sljit_stack stack, void allocator_data)
	{
	SLJIT_UNUSED_ARG(allocator_data);
	munmap((void*)stack->min_start, stack->end - stack->min_start);
	SLJIT_FREE(stack, allocator_data);
	}

	#endif /* _WIN32 */

	SLJIT_API_FUNC_ATTRIBUTE struct sljit_stack* SLJIT_FUNC sljit_allocate_stack(sljit_uw start_size, sljit_uw max_size, void *allocator_data)
	{
	struct sljit_stack *stack;
	void *ptr;
	sljit_sw page_align;

	SLJIT_UNUSED_ARG(allocator_data);

	if (start_size > max_size \|\| start_size < 1)
	return NULL;

	stack = (struct sljit_stack*)SLJIT_MALLOC(sizeof(struct sljit_stack), allocator_data);
	if (stack == NULL)
	return NULL;

	/* Align max_size. */
	page_align = get_page_alignment();
	max_size = (max_size + page_align) & ~page_align;

	#ifdef _WIN32
	ptr = VirtualAlloc(NULL, max_size, MEM_RESERVE, PAGE_READWRITE);
	if (!ptr) {
	SLJIT_FREE(stack, allocator_data);
	return NULL;
	}

	stack->min_start = (sljit_u8 *)ptr;
	stack->end = stack->min_start + max_size;
	stack->start = stack->end;

	if (sljit_stack_resize(stack, stack->end - start_size) == NULL) {
	sljit_free_stack(stack, allocator_data);
	return NULL;
	}
	#else /* !_WIN32 */
	#ifdef MAP_ANON
	ptr = mmap(NULL, max_size, PROT_READ \| PROT_WRITE, MAP_PRIVATE \| MAP_ANON, -1, 0);
	#else /* !MAP_ANON */
	if (SLJIT_UNLIKELY((dev_zero < 0) && open_dev_zero())) {
	SLJIT_FREE(stack, allocator_data);
	return NULL;
	}
	ptr = mmap(NULL, max_size, PROT_READ \| PROT_WRITE, MAP_PRIVATE, dev_zero, 0);
	#endif /* MAP_ANON */
	if (ptr == MAP_FAILED) {
	SLJIT_FREE(stack, allocator_data);
	return NULL;
	}
	stack->min_start = (sljit_u8 *)ptr;
	stack->end = stack->min_start + max_size;
	stack->start = stack->end - start_size;
	#endif /* _WIN32 */

	stack->top = stack->end;
	return stack;
	}

	SLJIT_API_FUNC_ATTRIBUTE sljit_u8 SLJIT_FUNC sljit_stack_resize(struct sljit_stack stack, sljit_u8 *new_start)
	{
	#if defined _WIN32 \|\| defined(POSIX_MADV_DONTNEED)
	sljit_uw aligned_old_start;
	sljit_uw aligned_new_start;
	sljit_sw page_align;
	#endif

	if ((new_start < stack->min_start) \|\| (new_start >= stack->end))
	return NULL;

	#ifdef _WIN32
	page_align = get_page_alignment();

	aligned_new_start = (sljit_uw)new_start & ~page_align;
	aligned_old_start = ((sljit_uw)stack->start) & ~page_align;
	if (aligned_new_start != aligned_old_start) {
	if (aligned_new_start < aligned_old_start) {
	if (!VirtualAlloc((void*)aligned_new_start, aligned_old_start - aligned_new_start, MEM_COMMIT, PAGE_READWRITE))
	return NULL;
	}
	else {
	if (!VirtualFree((void*)aligned_old_start, aligned_new_start - aligned_old_start, MEM_DECOMMIT))
	return NULL;
	}
	}
	#elif defined(POSIX_MADV_DONTNEED)
	if (stack->start < new_start) {
	page_align = get_page_alignment();

	aligned_new_start = (sljit_uw)new_start & ~page_align;
	aligned_old_start = ((sljit_uw)stack->start) & ~page_align;

	if (aligned_new_start > aligned_old_start) {
	posix_madvise((void*)aligned_old_start, aligned_new_start - aligned_old_start, POSIX_MADV_DONTNEED);
	#ifdef MADV_FREE
	madvise((void*)aligned_old_start, aligned_new_start - aligned_old_start, MADV_FREE);
	#endif /* MADV_FREE */
	}
	}
	#endif /* _WIN32 */

	stack->start = new_start;
	return new_start;
	}

	#endif /* SLJIT_UTIL_SIMPLE_STACK_ALLOCATION */

	#endif /* SLJIT_UTIL_STACK */