/* os.h                  -*-C++-*-
 *
 *************************************************************************
 *
 *  Copyright (C) 2009-2016, Intel Corporation
 *  All rights reserved.
 *  
 *  Redistribution and use in source and binary forms, with or without
 *  modification, are permitted provided that the following conditions
 *  are met:
 *  
 *    * Redistributions of source code must retain the above copyright
 *      notice, this list of conditions and the following disclaimer.
 *    * 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.
 *    * Neither the name of Intel Corporation nor the names of its
 *      contributors may be used to endorse or promote products derived
 *      from this software without specific prior written permission.
 *  
 *  THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS 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 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.
 *  
 *  *********************************************************************
 *  
 *  PLEASE NOTE: This file is a downstream copy of a file mainitained in
 *  a repository at cilkplus.org. Changes made to this file that are not
 *  submitted through the contribution process detailed at
 *  http://www.cilkplus.org/submit-cilk-contribution will be lost the next
 *  time that a new version is released. Changes only submitted to the
 *  GNU compiler collection or posted to the git repository at
 *  https://bitbucket.org/intelcilkruntime/intel-cilk-runtime.git are
 *  not tracked.
 *  
 *  We welcome your contributions to this open source project. Thank you
 *  for your assistance in helping us improve Cilk Plus.
 **************************************************************************/

/**
 * @file os.h
 *
 * @brief Low-level operating-system dependent facilities, not dependent on
 * any Cilk facilities.
 */

#ifndef INCLUDED_OS_DOT_H
#define INCLUDED_OS_DOT_H

#include "rts-common.h"
#include "cilk/common.h"
#include "cilk-tbb-interop.h"
#include "cilk_str_mem.h"

#ifdef __cplusplus
#   include <cstddef>
#else
#   include <stddef.h>
#endif

__CILKRTS_BEGIN_EXTERN_C


// /* Thread-local storage */
// #ifdef _WIN32
// typedef unsigned cilkos_tls_key_t;
// #else
// typedef pthread_key_t cilkos_tls_key_t;
// #endif
// cilkos_tls_key_t cilkos_allocate_tls_key();
// void cilkos_set_tls_pointer(cilkos_tls_key_t key, void* ptr);
// void* cilkos_get_tls_pointer(cilkos_tls_key_t key);

/* The RTS assumes that some thread-local state exists that stores the
   worker and reducer map currently associated with a thread.  These routines
   manipulate this state. */

/** @brief Thread-local state for cilk fibers. */
typedef struct cilk_fiber_sysdep cilk_fiber_sysdep;

/** @brief Initialize  all TLS variables for Cilk. */
COMMON_SYSDEP void __cilkrts_init_tls_variables(void);

/** @brief Set worker struct in TLS. */
COMMON_SYSDEP
void __cilkrts_set_tls_worker(__cilkrts_worker *w) cilk_nothrow;

/** @brief Get stack_op for TBB-interop structures from TLS. */
COMMON_SYSDEP
__cilk_tbb_stack_op_thunk *__cilkrts_get_tls_tbb_interop(void);

/** @brief Set stack_op for TBB-interop structures in TLS. */
COMMON_SYSDEP
void __cilkrts_set_tls_tbb_interop(__cilk_tbb_stack_op_thunk *t);

/**
 * @brief Get the pointer to the pedigree leaf node from TLS.
 *
 * Function to get a pointer to the thread's pedigree leaf node.  This
 * pointer can be NULL.
 */
COMMON_SYSDEP
__cilkrts_pedigree * __cilkrts_get_tls_pedigree_leaf(int create_new);

/**
 * @brief Sets the pointer to the pedigree leaf node in TLS.
 *
 * If the previous pointer value was not NULL, it is the caller's
 * responsibility to ensure that previous pointer value is saved and
 * freed.
 *
 * @param pedigree_leaf The leaf node to store into TLS.
 */ 
COMMON_SYSDEP
void __cilkrts_set_tls_pedigree_leaf(__cilkrts_pedigree* pedigree_leaf);


#if SUPPORT_GET_CURRENT_FIBER > 0
/**
 * @brief Get the cilk_fiber from TLS. 
 */
COMMON_SYSDEP
cilk_fiber_sysdep* cilkos_get_tls_cilk_fiber(void);

/**
 * @brief Set the cilk_fiber in TLS.
 *
 * @param fiber The fiber to store into TLS. 
 */
COMMON_SYSDEP
void cilkos_set_tls_cilk_fiber(cilk_fiber_sysdep* fiber);
#endif

/**
 * @brief Function for returning the current thread id.
 * @warning This function is useful for debugging purposes only.
 */
COMMON_SYSDEP
void* cilkos_get_current_thread_id(void);

/** @brief Return number of CPUs supported by this hardware, using whatever definition
   of CPU is considered appropriate. */
COMMON_SYSDEP int __cilkrts_hardware_cpu_count(void);

/** @brief Get current value of timer */
COMMON_SYSDEP unsigned long long __cilkrts_getticks(void);

/* Machine instructions */

/// Stall execution for a few cycles.
COMMON_SYSDEP void __cilkrts_short_pause(void);
/// Wrapper for xchg instruction
COMMON_SYSDEP int __cilkrts_xchg(volatile int *ptr, int x);

// Defines __cilkrts_fence - A macro for x86, a function call for other
// architectures
#include "os-fence.h"

COMMON_SYSDEP void __cilkrts_sleep(void); ///< Sleep briefly 
COMMON_SYSDEP void __cilkrts_yield(void); ///< Yield quantum 
COMMON_SYSDEP void __cilkrts_idle(void);  ///< Idle

/**
 * @brief Gets environment variable 'varname' and copy its value into 'value'.
 *
 * If the entire value, including the null terminator fits into 'vallen'
 * bytes, then returns the length of the value excluding the null.  Otherwise,
 * leaves the contents of 'value' undefined and returns the number of
 * characters needed to store the environment variable's value, *including*
 * the null terminator.
 *
 * @param value    Buffer to store value.
 * @param vallen   Length of value buffer
 * @param varname  Name of the environment variable.
 * @return         Length of value buffer (excluding the null).
 */
COMMON_SYSDEP __STDNS size_t cilkos_getenv(char* value, __STDNS size_t vallen,
                                           const char* varname);

/**
 * @brief Unrecoverable error: Print an error message and abort execution.
 */
COMMON_SYSDEP void cilkos_error(const char *fmt, ...);

/**
 * @brief Print a warning message and return.
 */
COMMON_SYSDEP void cilkos_warning(const char *fmt, ...);

/**
 * @brief Convert the user's specified stack size into a "reasonable"
 * value for the current OS.
 *
 * @param specified_stack_size   User-specified stack size.
 * @return New stack size value, modified for the OS.
 */
COMMON_SYSDEP size_t cilkos_validate_stack_size(size_t specified_stack_size);

/**
 * @brief Atomic addition: computes *p += x.
 * 
 * @param p  Pointer to value to update
 * @param x  Value of x.
 */
COMMON_SYSDEP long cilkos_atomic_add(volatile long* p, long x);

#ifdef _WIN32

/**
 * @brief Windows-only low-level functions for processor groups.
 */
typedef struct _GROUP_AFFINITY GROUP_AFFINITY;

/**
 * @brief Probe the executing OS to see if it supports processor
 * groups.  These functions are expected to be available in Windows 7
 * or later.
 */
void win_init_processor_groups(void);

unsigned long win_get_active_processor_count(unsigned short GroupNumber);
unsigned short win_get_active_processor_group_count(void);
int win_set_thread_group_affinity(/*HANDLE*/ void* hThread,
                                  const GROUP_AFFINITY *GroupAffinity,
                                  GROUP_AFFINITY* PreviousGroupAffinity);

/**
 * @brief Cleans up any state allocated in TLS.
 *
 * Only defined for Windows because Linux calls destructors for each
 * thread-local variable.
 */
void __cilkrts_per_thread_tls_cleanup(void);

#endif // _WIN32

__CILKRTS_END_EXTERN_C

#endif // ! defined(INCLUDED_OS_DOT_H)