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Retro68/gcc/libcilkrts/runtime/cilk_fiber.h
Wolfgang Thaller 65c83606fb Update gcc to 7.2.0, binutils to 2.29, newlib to 2.5.0
2017-10-07 02:16:47 +02:00

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/* cilk_fiber.h -*-C++-*-
*
*************************************************************************
*
* Copyright (C) 2012-2016, 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 cilk_fiber.h
*
* @brief Abstraction of a "fiber": A coprocess-like stack and auxiliary data
*/
#ifndef INCLUDED_CILK_FIBER_DOT_H
#define INCLUDED_CILK_FIBER_DOT_H
#include <cilk/common.h>
#ifdef __cplusplus
# include <cstddef>
#else
# include <stddef.h>
#endif
#include "bug.h"
#include "cilk-tbb-interop.h"
#include "spin_mutex.h"
#include "internal/abi.h" // Define __cilkrts_stack_frame
/**
* @brief Debugging level for Cilk fiber code.
*
* A value of 0 means no debugging.
* Higher values generate more debugging output.
*
*/
#ifndef FIBER_DEBUG
#define FIBER_DEBUG 0
#endif
/**
* @brief Flag for validating reference counts.
*
* Set to 1 to assert that fiber reference counts are reasonable.
*/
#define FIBER_CHECK_REF_COUNTS 1
/**
* @brief Flag to determine whether fibers support reference counting.
* We require reference counting only on Windows, for exception
* processing. Unix does not need reference counting.
*/
#if defined(_WIN32)
# define NEED_FIBER_REF_COUNTS 1
#endif
/**
* @brief Flag to enable support for the
* cilk_fiber_get_current_fiber() method.
*
* I'd like this flag to be 0. However, the cilk_fiber test depends
* on being able to call this method.
*/
#if !defined(SUPPORT_GET_CURRENT_FIBER)
# define SUPPORT_GET_CURRENT_FIBER 0
#endif
/**
* @brief Switch for enabling "fast path" check for fibers, which
* doesn't go to the heap or OS until checking the ancestors first.
*
* Doing this check seems to make the stress test in
* cilk_fiber_pool.t.cpp run faster. But it doesn't seem to make much
* difference in other benchmarks, so it is disabled by default.
*/
#define USE_FIBER_TRY_ALLOCATE_FROM_POOL 0
__CILKRTS_BEGIN_EXTERN_C
/// @brief Forward reference to fiber pool.
typedef struct cilk_fiber_pool cilk_fiber_pool;
/** @brief Opaque data structure representing a fiber */
typedef struct cilk_fiber cilk_fiber;
/** @brief Function pointer type for use as a fiber's "main" procedure */
typedef void (*cilk_fiber_proc)(cilk_fiber*);
/** @brief Data structure associated with each fiber. */
typedef struct cilk_fiber_data
{
__STDNS size_t stack_size; /**< Size of stack for fiber */
__cilkrts_worker* owner; /**< Worker using this fiber */
__cilkrts_stack_frame* resume_sf; /**< Stack frame to resume */
__cilk_tbb_pfn_stack_op stack_op_routine; /**< Cilk/TBB interop callback */
void* stack_op_data; /**< Data for Cilk/TBB callback */
void* client_data; /**< Data managed by client */
#ifdef _WIN32
char *initial_sp; /**< Initalized in fiber_stub */
# ifdef _WIN64
char *steal_frame_sp; /**< RSP for frame stealing work */
// Needed for exception handling so we can
// identify when about to unwind off stack
# endif
#endif
} cilk_fiber_data;
/** @brief Pool of cilk_fiber for fiber reuse
*
* Pools form a hierarchy, with each pool pointing to its parent. When the
* pool undeflows, it gets a fiber from its parent. When a pool overflows,
* it returns some fibers to its parent. If the root pool underflows, it
* allocates and initializes a new fiber from the heap but only if the total
* is less than max_size; otherwise, fiber creation fails.
*/
struct cilk_fiber_pool
{
spin_mutex* lock; ///< Mutual exclusion for pool operations
__STDNS size_t stack_size; ///< Size of stacks for fibers in this pool.
cilk_fiber_pool* parent; ///< @brief Parent pool.
///< If this pool is empty, get from parent
// Describes inactive fibers stored in the pool.
cilk_fiber** fibers; ///< Array of max_size fiber pointers
unsigned max_size; ///< Limit on number of fibers in pool
unsigned size; ///< Number of fibers currently in the pool
// Statistics on active fibers that were allocated from this pool,
// but no longer in the pool.
int total; ///< @brief Fibers allocated - fiber deallocated from pool
///< total may be negative for non-root pools.
int high_water; ///< High water mark of total fibers
int alloc_max; ///< Limit on number of fibers allocated from the heap/OS
};
/** @brief Initializes a cilk_fiber_pool structure
*
* @param pool - The address of the pool that is to be initialized
* @param parent - The address of this pool's parent, or NULL for root pool
* @param stack_size - Size of stacks for fibers allocated from this pool.
* @param buffer_size - The maximum number of fibers that may be pooled.
* @param alloc_max - Limit on # of fibers this pool can allocate from the heap.
* @param is_shared - True if accessing this pool needs a lock, false otherwise.
*/
void cilk_fiber_pool_init(cilk_fiber_pool* pool,
cilk_fiber_pool* parent,
size_t stack_size,
unsigned buffer_size,
int alloc_max,
int is_shared);
/** @brief Sets the maximum number of fibers to allocate from a root pool.
*
* @param root_pool - A root fiber pool
* @param max_fibers_to_allocate - The limit on # of fibers to allocate.
*
* Sets the maximum number of fibers that can be allocated from this
* pool and all its descendants. This pool must be a root pool.
*/
void cilk_fiber_pool_set_fiber_limit(cilk_fiber_pool* root_pool,
unsigned max_fibers_to_allocate);
/** @brief De-initalizes a cilk_fiber_pool
*
* @param pool - The address of the pool that is to be destroyed
*/
void cilk_fiber_pool_destroy(cilk_fiber_pool* pool);
/** @brief Allocates a new cilk_fiber.
*
* If the specified pool is empty, this method may choose to either
* allocate a fiber from the heap (if pool->total < pool->alloc_max),
* or retrieve a fiber from the parent pool.
*
* @note If a non-null fiber is returned, @c cilk_fiber_reset_state
* should be called on this fiber before using it.
*
* An allocated fiber begins with a reference count of 1.
* This method may lock @c pool or one of its ancestors.
*
* @pre pool should not be NULL.
*
* @param pool The fiber pool from which to retrieve a fiber.
* @return An allocated fiber, or NULL if failed to allocate.
*/
cilk_fiber* cilk_fiber_allocate(cilk_fiber_pool* pool);
/** @brief Allocate and initialize a new cilk_fiber using memory from
* the heap and/or OS.
*
* The allocated fiber begins with a reference count of 1.
*
* @param stack_size The size (in bytes) to be allocated for the fiber's
* stack.
* @return An initialized fiber. This method should not return NULL
* unless some exceptional condition has occurred.
*/
cilk_fiber* cilk_fiber_allocate_from_heap(size_t stack_size);
/** @brief Resets an fiber object just allocated from a pool with the
* specified proc.
*
* After this call, cilk_fiber_data object associated with this fiber
* is filled with zeros.
*
* This function can be called only on a fiber that has been allocated
* from a pool, but never used.
*
* @param fiber The fiber to reset and initialize.
* @param start_proc The function to run when switching to the fiber. If
* null, the fiber can be used with cilk_fiber_run_proc()
* but not with cilk_fiber_resume().
*/
void cilk_fiber_reset_state(cilk_fiber* fiber,
cilk_fiber_proc start_proc);
/** @brief Remove a reference from this fiber, possibly deallocating it.
*
* This fiber is deallocated only when there are no other references
* to it. Deallocation happens either by returning the fiber to the
* specified pool, or returning it to the heap.
*
* A fiber that is currently executing should not remove the last
* reference to itself.
*
* When a fiber is deallocated, destructors are not called for the
* objects (if any) still on its stack. The fiber's stack and fiber
* data is returned to the stack pool but the client fiber data is not
* deallocated.
*
* If the pool overflows because of a deallocation, then some fibers
* will be returned to the parent pool. If the root pool overflows,
* then the fiber is returned to the heap.
*
* @param fiber The Cilk fiber to remove a reference to.
* @param pool The fiber pool to which the fiber should be returned. The
* caller is assumed to have exclusive access to the pool
* either because there is no contention for it or because
* its lock has been acquired. If pool is NULL, any
* deallocated fiber is destroyed and returned to the
* heap.
*
* @return Final reference count. If the count is 0, the fiber was
* returned to a pool or the heap.
*/
int cilk_fiber_remove_reference(cilk_fiber *fiber, cilk_fiber_pool *pool);
/** @brief Allocates and intializes this thread's main fiber
*
* Each thread has an "implicit" main fiber that control's the
* thread's initial stack. This function makes this fiber visible to
* the client and allocates the Cilk-specific aspects of the implicit
* fiber. A call to this function must be paired with a call to
* cilk_fiber_deallocate_fiber_from_thread()
* or a memory leak (or worse) will result.
*
* A fiber allocated from a thread begins with a reference count of 2.
* One is for being allocated, and one is for being active.
* (A fiber created from a thread is automatically currently executing.)
* The matching calls above each decrement the reference count by 1.
*
* @return A fiber for the currently executing thread.
*/
cilk_fiber* cilk_fiber_allocate_from_thread(void);
/** @brief Remove a fiber created from a thread,
* possibly deallocating it.
*
* Same as cilk_fiber_remove_reference, except that it works on fibers
* created via cilk_fiber_allocate_from_thread().
*
* Fibers created from a thread are never returned to a pool.
*
* @param fiber The Cilk fiber to remove a reference from.
* @return Final reference count. If the count is 0, the fiber was
* returned to the heap.
*/
int cilk_fiber_remove_reference_from_thread(cilk_fiber *fiber);
/** @brief Deallocate a fiber created from a thread,
* possibly destroying it.
*
* This method decrements the reference count of the fiber by 2, and
* destroys the fiber struct if the reference count is 0.
*
* OS-specific cleanup for the fiber executes unconditionally with
* this method. The destruction of the actual object, however, does
* not occur unless the reference count is 0.
*
* @param fiber The cilk_fiber to deallocate from a thread.
* @return Final reference count. If the count is 0, the fiber was
* returned to the heap.
*/
int cilk_fiber_deallocate_from_thread(cilk_fiber *fiber);
/** @brief Returns true if this fiber is allocated from a thread.
*/
int cilk_fiber_is_allocated_from_thread(cilk_fiber *fiber);
/** @brief Suspend execution on current fiber resumes other fiber.
*
* Suspends the current fiber and transfers control to a new fiber. Execution
* on the new fiber resumes from the point at which fiber suspended itself to
* run a different fiber. If fiber was freshly allocated, then runs the
* start_proc function specified at allocation. This function returns when
* another fiber resumes the self fiber. Note that the state of the
* floating-point control register (i.e., the register that controls rounding
* mode, etc.) is valid but indeterminate on return -- different
* implementations will have different results.
*
* When the @c self fiber is resumed, execution proceeds as though
* this function call returns.
*
* This operation increments the reference count of @p other.
* This operation decrements the reference count of @p self.
*
* @param self Fiber to switch from. Must equal current fiber.
* @param other Fiber to switch to.
*/
void cilk_fiber_suspend_self_and_resume_other(cilk_fiber* self,
cilk_fiber* other);
/** @brief Removes a reference from the currently executing fiber and
* resumes other fiber.
*
* Removes a reference from @p self and transfer control to @p other
* fiber. Execution on @p other resumes from the point at which @p
* other suspended itself to run a different fiber. If @p other fiber
* was freshly allocated, then runs the function specified at
* creation.
*
*
* This operation increments the reference count of @p other.
*
* This operation conceptually decrements the reference count of
* @p self twice, once to suspend it, and once to remove a reference to
* it. Then, if the count is 0, it is returned to the specified pool
* or destroyed.
*
* @pre @p self is the currently executing fiber.
*
* @param self Fiber to remove reference switch from.
* @param self_pool Pool to which the current fiber should be returned
* @param other Fiber to switch to.
*/
NORETURN
cilk_fiber_remove_reference_from_self_and_resume_other(cilk_fiber* self,
cilk_fiber_pool* self_pool,
cilk_fiber* other);
/** @brief Set the proc method to execute immediately after a switch
* to this fiber.
*
* The @c post_switch_proc method executes immediately after switching
* away form @p self fiber to some other fiber, but before @c self
* gets cleaned up.
*
* @note A fiber can have only one post_switch_proc method at a time.
* If this method is called multiple times before switching to the
* fiber, only the last proc method will execute.
*
* @param self Fiber.
* @param post_switch_proc Proc method to execute immediately after switching to this fiber.
*/
void cilk_fiber_set_post_switch_proc(cilk_fiber* self, cilk_fiber_proc post_switch_proc);
/** @brief Invoke TBB stack op for this fiber.
*
* @param fiber Fiber to invoke stack op for.
* @param op The stack op to invoke
*/
void cilk_fiber_invoke_tbb_stack_op(cilk_fiber* fiber, __cilk_tbb_stack_op op);
/** @brief Returns the fiber data associated with the specified fiber.
*
* The returned struct is owned by the fiber and is deallocated automatically
* when the fiber is destroyed. However, the client_data field is owned by
* the client and must be deallocated separately. When called for a
* newly-allocated fiber, the returned data is zero-filled.
*
* @param fiber The fiber for which data is being requested.
* @return The fiber data for the specified fiber
*/
cilk_fiber_data* cilk_fiber_get_data(cilk_fiber* fiber);
/** @brief Retrieve the owner field from the fiber.
*
* This method is provided for convenience. One can also get the
* fiber data, and then get the owner field.
*/
__CILKRTS_INLINE
__cilkrts_worker* cilk_fiber_get_owner(cilk_fiber* fiber)
{
// TBD: We really want a static assert here, that this cast is
// doing the right thing.
cilk_fiber_data* fdata = (cilk_fiber_data*)fiber;
return fdata->owner;
}
/** @brief Sets the owner field of a fiber.
*
* This method is provided for convenience. One can also get the
* fiber data, and then get the owner field.
*/
__CILKRTS_INLINE
void cilk_fiber_set_owner(cilk_fiber* fiber, __cilkrts_worker* owner)
{
// TBD: We really want a static assert here, that this cast is
// doing the right thing.
cilk_fiber_data* fdata = (cilk_fiber_data*)fiber;
fdata->owner = owner;
}
/** @brief Returns true if this fiber is resumable.
*
* A fiber is considered resumable when it is not currently being
* executed.
*
* This function is used by Windows exception code.
* @param fiber The fiber to check.
* @return Nonzero value if fiber is resumable.
*/
int cilk_fiber_is_resumable(cilk_fiber* fiber);
/**
* @brief Returns the base of this fiber's stack.
*
* On some platforms (e.g., Windows), the fiber must have started
* running before we can get this information.
*
* @param fiber The fiber to get the stack pointer from.
* @return The base of the stack, or NULL if this
* information is not available yet.
*/
char* cilk_fiber_get_stack_base(cilk_fiber* fiber);
/****************************************************************************
* TBB interop functions
* **************************************************************************/
/**
* @brief Set the TBB callback information for a stack
*
* @param fiber The fiber to set the TBB callback information for
* @param o The TBB callback thunk. Specifies the callback address and
* context value.
*/
void cilk_fiber_set_stack_op(cilk_fiber *fiber,
__cilk_tbb_stack_op_thunk o);
/**
* @brief Save the TBB callback address and context value in
* thread-local storage.
*
* We'll use it later when the thread binds to a worker.
*
* @param o The TBB callback thunk which is to be saved.
*/
void cilk_fiber_tbb_interop_save_stack_op_info(__cilk_tbb_stack_op_thunk o);
/**
* @brief Move TBB stack-op info from thread-local storage and store
* it into the fiber.
*
* Called when we bind a thread to the runtime. If there is any TBB
* interop information in thread-local storage, bind it to the stack
* now.
*
* @pre \c fiber should not be NULL.
* @param fiber The fiber that should take over the TBB interop information.
*/
void cilk_fiber_tbb_interop_use_saved_stack_op_info(cilk_fiber *fiber);
/**
* @brief Free any TBB interop information saved in thread-local storage
*/
void cilk_fiber_tbb_interop_free_stack_op_info(void);
/**
* @brief Migrate any TBB interop information from a cilk_fiber to
* thread-local storage.
*
* Returns immediately if no TBB interop information has been
* associated with the stack.
*
* @param fiber The cilk_fiber who's TBB interop information should be
* saved in thread-local storage.
*/
void cilk_fiber_tbb_interop_save_info_from_stack(cilk_fiber* fiber);
#if SUPPORT_GET_CURRENT_FIBER
/** @brief Returns the fiber associated with the currently executing thread
*
* @note This function is currently used only for testing the Cilk
* runtime.
*
* @return Fiber associated with the currently executing thread or NULL if no
* fiber was associated with this thread.
*/
cilk_fiber* cilk_fiber_get_current_fiber(void);
#endif
#if NEED_FIBER_REF_COUNTS
/** @brief Returns true if this fiber has reference count > 0.
*
* @param fiber The fiber to check for references.
* @return Nonzero value if the fiber has references.
*/
int cilk_fiber_has_references(cilk_fiber *fiber);
/** @brief Returns the value of the reference count.
*
* @param fiber The fiber to check for references.
* @return The value of the reference count of fiber.
*/
int cilk_fiber_get_ref_count(cilk_fiber *fiber);
/** @brief Adds a reference to this fiber.
*
* Increments the reference count of a current fiber. Fibers with
* nonzero reference count will not be freed or returned to a fiber
* pool.
*
* @param fiber The fiber to add a reference to.
*/
void cilk_fiber_add_reference(cilk_fiber *fiber);
#endif // NEED_FIBER_REF_COUNTS
__CILKRTS_END_EXTERN_C
#ifdef __cplusplus
// Some C++ implementation details
/// Opaque declaration of a cilk_fiber_sysdep object.
struct cilk_fiber_sysdep;
/**
* cilk_fiber is a base-class for system-dependent fiber implementations.
*/
struct cilk_fiber : protected cilk_fiber_data
{
protected:
// This is a rare acceptable use of protected inheritence and protected
// variable access: when the base class and derived class collaborate
// tightly to comprise a single component.
/// For overloading constructor of cilk_fiber.
enum from_thread_t { from_thread = 1 };
// Boolean flags capturing the status of the fiber.
// Each one can be set independently.
// A default fiber is constructed with a flag value of 0.
static const int RESUMABLE = 0x01; ///< True if the fiber is in a suspended state and can be resumed.
static const int ALLOCATED_FROM_THREAD = 0x02; ///< True if fiber was allocated from a thread.
cilk_fiber_proc m_start_proc; ///< Function to run on start up/reset
cilk_fiber_proc m_post_switch_proc; ///< Function that executes when we first switch to a new fiber from a different one.
cilk_fiber* m_pending_remove_ref;///< Fiber to possibly delete on start up or resume
cilk_fiber_pool* m_pending_pool; ///< Pool where m_pending_remove_ref should go if it is deleted.
unsigned m_flags; ///< Captures the status of this fiber.
#if NEED_FIBER_REF_COUNTS
volatile long m_outstanding_references; ///< Counts references to this fiber.
#endif
/// Creates a fiber with NULL data.
cilk_fiber();
/**
* @brief Creates a fiber with user-specified arguments.
*
* @param stack_size Size of stack to use for this fiber.
*/
cilk_fiber(std::size_t stack_size);
/// Empty destructor.
~cilk_fiber();
/**
* @brief Performs any actions that happen after switching from
* one fiber to another.
*
* These actions are:
* 1. Execute m_post_switch_proc on a fiber.
* 2. Do any pending deallocations from the previous fiber.
*/
void do_post_switch_actions();
/**
*@brief Helper method that converts a @c cilk_fiber object into a
* @c cilk_fiber_sysdep object.
*
* The @c cilk_fiber_sysdep object contains the system-dependent parts
* of the implementation of a @\c cilk_fiber.
*
* We could have @c cilk_fiber_sysdep inherit from @c cilk_fiber and
* then use virtual functions. But since a given platform only uses
* one definition of @c cilk_fiber_sysdep at a time, we statically
* cast between them.
*/
inline cilk_fiber_sysdep* sysdep();
/**
* @brief Set resumable flag to specified state.
*/
inline void set_resumable(bool state) {
m_flags = state ? (m_flags | RESUMABLE) : (m_flags & (~RESUMABLE));
}
/**
*@brief Set the allocated_from_thread flag.
*/
inline void set_allocated_from_thread(bool state) {
m_flags = state ? (m_flags | ALLOCATED_FROM_THREAD) : (m_flags & (~ALLOCATED_FROM_THREAD));
}
public:
/**
* @brief Allocates and initializes a new cilk_fiber, either from
* the specified pool or from the heap.
*
* @pre pool should not be NULL.
*/
static cilk_fiber* allocate(cilk_fiber_pool* pool);
/**
* @brief Allocates a fiber from the heap.
*/
static cilk_fiber* allocate_from_heap(size_t stack_size);
/**
* @brief Return a fiber to the heap.
*/
void deallocate_to_heap();
/**
* @brief Reset the state of a fiber just allocated from a pool.
*/
void reset_state(cilk_fiber_proc start_proc);
/**
* @brief Remove a reference from this fiber, possibly
* deallocating it if the reference count becomes 0.
*
* @param pool The fiber pool to which this fiber should be returned.
* @return The final reference count.
*/
int remove_reference(cilk_fiber_pool* pool);
/**
* @brief Deallocate the fiber by returning it to the pool.
* @pre This method should only be called if the reference count
* is 0.
*
* @param pool The fiber pool to return this fiber to. If NULL,
* fiber is returned to the heap.
*/
void deallocate_self(cilk_fiber_pool *pool);
/** @brief Allocates and intializes this thread's main fiber. */
static cilk_fiber* allocate_from_thread();
/** @brief Deallocate a fiber created from a thread,
* possibly destroying it.
*
* This method decrements the reference count of this fiber by 2,
* and destroys the fiber if the reference count is 0.
*
* OS-specific cleanup for the fiber executes unconditionally with for
* this method. The destruction of the actual object, however, does
* not occur unless the reference count is 0.
*
* @return Final reference count. If the count is 0, the fiber was
* returned to the heap.
*/
int deallocate_from_thread();
/** @brief Removes a reference from this fiber.
*
* This method deallocates this fiber if the reference count
* becomes 0.
*
* @pre This fiber must be allocated from a thread.
* @return The final reference count of this fiber.
*/
int remove_reference_from_thread();
#if SUPPORT_GET_CURRENT_FIBER
/** @brief Get the current fiber from TLS.
*
* @note This function is only used for testing the runtime.
*/
static cilk_fiber* get_current_fiber();
#endif
/** @brief Suspend execution on current fiber resumes other fiber.
*
* Control returns after resuming execution of the self fiber.
*/
void suspend_self_and_resume_other(cilk_fiber* other);
/** @brief Removes a reference from the currently executing fiber
* and resumes other fiber.
*
* This fiber may be returned to a pool or deallocated.
*/
NORETURN remove_reference_from_self_and_resume_other(cilk_fiber_pool* self_pool,
cilk_fiber* other);
/** @brief Set the proc method to execute immediately after a switch
* to this fiber.
*
* @param post_switch_proc Proc method to execute immediately
* after switching to this fiber.
*/
inline void set_post_switch_proc(cilk_fiber_proc post_switch_proc) {
m_post_switch_proc = post_switch_proc;
}
/** @brief Returns true if this fiber is resumable.
*
* A fiber is considered resumable when it is not currently being
* executed.
*/
inline bool is_resumable(void) {
return (m_flags & RESUMABLE);
}
/** @brief Returns true if fiber was allocated from a thread. */
inline bool is_allocated_from_thread(void) {
return (m_flags & ALLOCATED_FROM_THREAD);
}
/**
*@brief Get the address at the base of the stack for this fiber.
*/
inline char* get_stack_base();
/** @brief Return the data for this fiber. */
cilk_fiber_data* get_data() { return this; }
/** @brief Return the data for this fiber. */
cilk_fiber_data const* get_data() const { return this; }
#if NEED_FIBER_REF_COUNTS
/** @brief Verifies that this fiber's reference count equals v. */
inline void assert_ref_count_equals(long v) {
#if FIBER_CHECK_REF_COUNTS
CILK_ASSERT(m_outstanding_references >= v);
#endif
}
/** @brief Verifies that this fiber's reference count is at least v. */
inline void assert_ref_count_at_least(long v) {
#if FIBER_CHECK_REF_COUNTS
CILK_ASSERT(m_outstanding_references >= v);
#endif
}
/** @brief Get reference count. */
inline long get_ref_count() { return m_outstanding_references; }
/** @brief Initialize reference count.
* Operation is not atomic.
*/
inline void init_ref_count(long v) { m_outstanding_references = v; }
// For Windows, updates to the fiber reference count need to be
// atomic, because exceptions can live on a stack that we are not
// currently executing on. Thus, we can update the reference
// count of a fiber we are not currently executing on.
/** @brief Increment reference count for this fiber [Windows]. */
inline void inc_ref_count() { atomic_inc_ref_count(); }
/** @brief Decrement reference count for this fiber [Windows]. */
inline long dec_ref_count() { return atomic_dec_ref_count(); }
/** @brief Subtract v from the reference count for this fiber [Windows]. */
inline long sub_from_ref_count(long v) { return atomic_sub_from_ref_count(v); }
#else // NEED_FIBER_REF_COUNTS
// Without reference counting, we have placeholder methods.
inline void init_ref_count(long v) { }
inline void inc_ref_count() { }
// With no reference counting, dec_ref_count always return 0.
// Thus, anyone checking is always the "last" one.
inline long dec_ref_count() { return 0; }
inline long sub_from_ref_count(long v) { return 0; }
// The assert methods do nothing.
inline void assert_ref_count_equals(long v) { }
inline void assert_ref_count_at_least(long v) { }
#endif
/**
* @brief Call TBB to tell it about an "interesting" event.
*
* @param op Value specifying the event to track.
*/
void invoke_tbb_stack_op(__cilk_tbb_stack_op op);
private:
/**
* @brief Helper method: try to allocate a fiber from this pool or
* its ancestors without going to the OS / heap.
*
* Returns allocated pool, or NULL if no pool is found.
*
* If pool contains a suitable fiber. Return it. Otherwise, try to
* recursively grab a fiber from the parent pool, if there is one.
*
* This method will not allocate a fiber from the heap.
*/
static cilk_fiber* try_allocate_from_pool_recursive(cilk_fiber_pool* pool);
#if NEED_FIBER_REF_COUNTS
/**
* @brief Atomic increment of reference count.
*/
void atomic_inc_ref_count();
/**
* @brief Atomic decrement of reference count.
*/
long atomic_dec_ref_count();
/**
* @brief Atomic subtract of v from reference count.
* @param v Value to subtract.
*/
long atomic_sub_from_ref_count(long v);
#endif // NEED_FIBER_REF_COUNTS
};
#endif // __cplusplus
#endif // ! defined(INCLUDED_CILK_FIBER_DOT_H)
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