gcc/libcilkrts/include/cilk/reducer_opor.h
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/* reducer_opor.h -*- C++ -*-
*
* @copyright
* Copyright (C) 2009-2013, Intel Corporation
* All rights reserved.
*
* @copyright
* 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.
*
* @copyright
* 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.
*/
/** @file reducer_opor.h
*
* @brief Defines classes for doing parallel bitwise or reductions.
*
* @ingroup ReducersOr
*
* @see ReducersOr
*/
#ifndef REDUCER_OPOR_H_INCLUDED
#define REDUCER_OPOR_H_INCLUDED
#include <cilk/reducer.h>
/** @defgroup ReducersOr Bitwise Or Reducers
*
* Bitwise and reducers allow the computation of the bitwise and of a set of
* values in parallel.
*
* @ingroup Reducers
*
* You should be familiar with @ref pagereducers "Cilk reducers", described in
* file `reducers.md`, and particularly with @ref reducers_using, before trying
* to use the information in this file.
*
* @section redopor_usage Usage Example
*
* cilk::reducer< cilk::op_or<unsigned> > r;
* cilk_for (int i = 0; i != N; ++i) {
* *r |= a[i];
* }
* unsigned result;
* r.move_out(result);
*
* @section redopor_monoid The Monoid
*
* @subsection redopor_monoid_values Value Set
*
* The value set of a bitwise or reducer is the set of values of `Type`, which
* is expected to be a builtin integer type which has a representation as a
* sequence of bits (or something like it, such as `bool` or `std::bitset`).
*
* @subsection redopor_monoid_operator Operator
*
* The operator of a bitwise or reducer is the bitwise or operator, defined by
* the “`|`” binary operator on `Type`.
*
* @subsection redopor_monoid_identity Identity
*
* The identity value of the reducer is the value whose representation
* contains all 0-bits. This is expected to be the value of the default
* constructor `Type()`.
*
* @section redopor_operations Operations
*
* @subsection redopor_constructors Constructors
*
* reducer() // identity
* reducer(const Type& value)
* reducer(move_in(Type& variable))
*
* @subsection redopor_get_set Set and Get
*
* r.set_value(const Type& value)
* const Type& = r.get_value() const
* r.move_in(Type& variable)
* r.move_out(Type& variable)
*
* @subsection redopor_initial Initial Values
*
* If a bitwise or reducer is constructed without an explicit initial value,
* then its initial value will be its identity value, as long as `Type`
* satisfies the requirements of @ref redopor_types.
*
* @subsection redopor_view_ops View Operations
*
* *r |= a
* *r = *r | a
* *r = *r | a1 | a2 … | an
*
* @section redopor_types Type and Operator Requirements
*
* `Type` must be `Copy Constructible`, `Default Constructible`, and
* `Assignable`.
*
* The operator “`|=`” must be defined on `Type`, with `x |= a` having the
* same meaning as `x = x | a`.
*
* The expression `Type()` must be a valid expression which yields the
* identity value (the value of `Type` whose representation consists of all
* 0-bits).
*
* @section redopor_in_c Bitwise Or Reducers in C
*
* The @ref CILK_C_REDUCER_OPOR and @ref CILK_C_REDUCER_OPOR_TYPE macros can
* be used to do bitwise or reductions in C. For example:
*
* CILK_C_REDUCER_OPOR(r, uint, 0);
* CILK_C_REGISTER_REDUCER(r);
* cilk_for(int i = 0; i != n; ++i) {
* REDUCER_VIEW(r) |= a[i];
* }
* CILK_C_UNREGISTER_REDUCER(r);
* printf("The bitwise OR of the elements of a is %x\n", REDUCER_VIEW(r));
*
* See @ref reducers_c_predefined.
*/
#ifdef __cplusplus
namespace cilk {
/** The bitwise or reducer view class.
*
* This is the view class for reducers created with
* `cilk::reducer< cilk::op_or<Type> >`. It holds the accumulator variable for
* the reduction, and allows only `or` operations to be performed on it.
*
* @note The reducer “dereference” operation (`reducer::operator *()`)
* yields a reference to the view. Thus, for example, the view classs
* `|=` operation would be used in an expression like `*r |= a`, where
* `r` is an opmod reducer variable.
*
* @tparam Type The type of the contained accumulator variable. This will
* be the value type of a monoid_with_view that is
* instantiated with this view.
*
* @see ReducersOr
* @see op_or
*
* @ingroup ReducersOr
*/
template <typename Type>
class op_or_view : public scalar_view<Type>
{
typedef scalar_view<Type> base;
public:
/** Class to represent the right-hand side of `*reducer = *reducer | value`.
*
* The only assignment operator for the op_or_view class takes an
* rhs_proxy as its operand. This results in the syntactic restriction
* that the only expressions that can be assigned to an op_or_view are
* ones which generate an rhs_proxy — that is, expressions of the form
* `op_or_view | value ... | value`.
*
* @warning
* The lhs and rhs views in such an assignment must be the same;
* otherwise, the behavior will be undefined. (I.e., `v1 = v1 | x` is
* legal; `v1 = v2 | x` is illegal.) This condition will be checked with
* a runtime assertion when compiled in debug mode.
*
* @see op_or_view
*/
class rhs_proxy {
friend class op_or_view;
const op_or_view* m_view;
Type m_value;
// Constructor is invoked only from op_or_view::operator|().
//
rhs_proxy(const op_or_view* view, const Type& value) : m_view(view), m_value(value) {}
rhs_proxy& operator=(const rhs_proxy&); // Disable assignment operator
rhs_proxy(); // Disable default constructor
public:
/** Bitwise or with an additional rhs value. If `v` is an op_or_view
* and `a1` is a value, then the expression `v | a1` invokes the
* views `operator|()` to create an rhs_proxy for `(v, a1)`; then
* `v | a1 | a2` invokes the rhs_proxys `operator|()` to create a new
* rhs_proxy for `(v, a1|a2)`. This allows the right-hand side of an
* assignment to be not just `view | value`, but
( `view | value | value ... | value`. The effect is that
*
* v = v | a1 | a2 ... | an;
*
* is evaluated as
*
* v = v | (a1 | a2 ... | an);
*/
rhs_proxy& operator|(const Type& x) { m_value |= x; return *this; }
};
/** Default/identity constructor. This constructor initializes the
* contained value to `Type()`.
*/
op_or_view() : base() {}
/** Construct with a specified initial value.
*/
explicit op_or_view(const Type& v) : base(v) {}
/** Reduction operation.
*
* This function is invoked by the @ref op_or monoid to combine the views
* of two strands when the right strand merges with the left one. It
* “ors” the value contained in the left-strand view by the value
* contained in the right-strand view, and leaves the value in the
* right-strand view undefined.
*
* @param right A pointer to the right-strand view. (`this` points to
* the left-strand view.)
*
* @note Used only by the @ref op_or monoid to implement the monoid
* reduce operation.
*/
void reduce(op_or_view* right) { this->m_value |= right->m_value; }
/** @name Accumulator variable updates.
*
* These functions support the various syntaxes for “oring” the
* accumulator variable contained in the view with some value.
*/
//@{
/** Or the accumulator variable with @a x.
*/
op_or_view& operator|=(const Type& x) { this->m_value |= x; return *this; }
/** Create an object representing `*this | x`.
*
* @see rhs_proxy
*/
rhs_proxy operator|(const Type& x) const { return rhs_proxy(this, x); }
/** Assign the result of a `view | value` expression to the view. Note that
* this is the only assignment operator for this class.
*
* @see rhs_proxy
*/
op_or_view& operator=(const rhs_proxy& rhs) {
__CILKRTS_ASSERT(this == rhs.m_view);
this->m_value |= rhs.m_value;
return *this;
}
//@}
};
/** Monoid class for bitwise or reductions. Instantiate the cilk::reducer
* template class with an op_or monoid to create a bitwise or reducer
* class. For example, to compute the bitwise or of a set of `unsigned long`
* values:
*
* cilk::reducer< cilk::op_or<unsigned long> > r;
*
* @tparam Type The reducer value type.
* @tparam Align If `false` (the default), reducers instantiated on this
* monoid will be naturally aligned (the Cilk library 1.0
* behavior). If `true`, reducers instantiated on this monoid
* will be cache-aligned for binary compatibility with
* reducers in Cilk library version 0.9.
*
* @see ReducersOr
* @see op_or_view
*
* @ingroup ReducersOr
*/
template <typename Type, bool Align = false>
struct op_or : public monoid_with_view<op_or_view<Type>, Align> {};
/** Deprecated bitwise or reducer class.
*
* reducer_opor is the same as @ref reducer<@ref op_or>, except that
* reducer_opor is a proxy for the contained view, so that accumulator
* variable update operations can be applied directly to the reducer. For
* example, a value is ored with a `reducer<%op_or>` with `*r |= a`, but a
* value can be ored with a `%reducer_opor` with `r |= a`.
*
* @deprecated Users are strongly encouraged to use `reducer<monoid>`
* reducers rather than the old wrappers like reducer_opor.
* The `reducer<monoid>` reducers show the reducer/monoid/view
* architecture more clearly, are more consistent in their
* implementation, and present a simpler model for new
* user-implemented reducers.
*
* @note Implicit conversions are provided between `%reducer_opor`
* and `reducer<%op_or>`. This allows incremental code
* conversion: old code that used `%reducer_opor` can pass a
* `%reducer_opor` to a converted function that now expects a
* pointer or reference to a `reducer<%op_or>`, and vice
* versa.
*
* @tparam Type The value type of the reducer.
*
* @see op_or
* @see reducer
* @see ReducersOr
*
* @ingroup ReducersOr
*/
template <typename Type>
class reducer_opor : public reducer< op_or<Type, true> >
{
typedef reducer< op_or<Type, true> > base;
using base::view;
public:
/// The view type for the reducer.
typedef typename base::view_type view_type;
/// The views rhs proxy type.
typedef typename view_type::rhs_proxy rhs_proxy;
/// The view type for the reducer.
typedef view_type View;
/// The monoid type for the reducer.
typedef typename base::monoid_type Monoid;
/** @name Constructors
*/
//@{
/** Default (identity) constructor.
*
* Constructs the wrapper with the default initial value of `Type()`.
*/
reducer_opor() {}
/** Value constructor.
*
* Constructs the wrapper with a specified initial value.
*/
explicit reducer_opor(const Type& initial_value) : base(initial_value) {}
//@}
/** @name Forwarded functions
* @details Functions that update the contained accumulator variable are
* simply forwarded to the contained @ref op_and_view. */
//@{
/// @copydoc op_or_view::operator|=(const Type&)
reducer_opor& operator|=(const Type& x)
{
view() |= x; return *this;
}
// The legacy definition of reducer_opor::operator|() has different
// behavior and a different return type than this definition. The legacy
// version is defined as a member function, so this new version is defined
// as a free function to give it a different signature, so that they wont
// end up sharing a single object file entry.
/// @copydoc op_or_view::operator|(const Type&) const
friend rhs_proxy operator|(const reducer_opor& r, const Type& x)
{
return r.view() | x;
}
/// @copydoc op_and_view::operator=(const rhs_proxy&)
reducer_opor& operator=(const rhs_proxy& temp)
{
view() = temp; return *this;
}
//@}
/** @name Dereference
* @details Dereferencing a wrapper is a no-op. It simply returns the
* wrapper. Combined with the rule that the wrapper forwards view
* operations to its contained view, this means that view operations can
* be written the same way on reducers and wrappers, which is convenient
* for incrementally converting old code using wrappers to use reducers
* instead. That is:
*
* reducer< op_and<int> > r;
* *r &= a; // *r returns the view
* // operator &= is a view member function
*
* reducer_opand<int> w;
* *w &= a; // *w returns the wrapper
* // operator &= is a wrapper member function that
* // calls the corresponding view function
*/
//@{
reducer_opor& operator*() { return *this; }
reducer_opor const& operator*() const { return *this; }
reducer_opor* operator->() { return this; }
reducer_opor const* operator->() const { return this; }
//@}
/** @name Upcast
* @details In Cilk library 0.9, reducers were always cache-aligned. In
* library 1.0, reducer cache alignment is optional. By default, reducers
* are unaligned (i.e., just naturally aligned), but legacy wrappers
* inherit from cache-aligned reducers for binary compatibility.
*
* This means that a wrapper will automatically be upcast to its aligned
* reducer base class. The following conversion operators provide
* pseudo-upcasts to the corresponding unaligned reducer class.
*/
//@{
operator reducer< op_or<Type, false> >& ()
{
return *reinterpret_cast< reducer< op_or<Type, false> >* >(this);
}
operator const reducer< op_or<Type, false> >& () const
{
return *reinterpret_cast< const reducer< op_or<Type, false> >* >(this);
}
//@}
};
/// @cond internal
/** Metafunction specialization for reducer conversion.
*
* This specialization of the @ref legacy_reducer_downcast template class
* defined in reducer.h causes the `reducer< op_or<Type> >` class to have an
* `operator reducer_opor<Type>& ()` conversion operator that statically
* downcasts the `reducer<op_or>` to the corresponding `reducer_opor` type.
* (The reverse conversion, from `reducer_opor` to `reducer<op_or>`, is just
* an upcast, which is provided for free by the language.)
*
* @ingroup ReducersOr
*/
template <typename Type, bool Align>
struct legacy_reducer_downcast<reducer<op_or<Type, Align> > >
{
typedef reducer_opor<Type> type;
};
/// @endcond
} // namespace cilk
#endif /* __cplusplus */
/** @ingroup ReducersOr
*/
//@{
/** @name C language reducer macros
*
* These macros are used to declare and work with op_or reducers in C code.
*
* @see @ref page_reducers_in_c
*/
//@{
__CILKRTS_BEGIN_EXTERN_C
/** Opor reducer type name.
*
* This macro expands into the identifier which is the name of the op_or
* reducer type for a specified numeric type.
*
* @param tn The @ref reducers_c_type_names "numeric type name" specifying
* the type of the reducer.
*
* @see @ref reducers_c_predefined
* @see ReducersOr
*/
#define CILK_C_REDUCER_OPOR_TYPE(tn) \
__CILKRTS_MKIDENT(cilk_c_reducer_opor_,tn)
/** Declare an op_or reducer object.
*
* This macro expands into a declaration of an op_or reducer object for a
* specified numeric type. For example:
*
* CILK_C_REDUCER_OPOR(my_reducer, ulong, 0);
*
* @param obj The variable name to be used for the declared reducer object.
* @param tn The @ref reducers_c_type_names "numeric type name" specifying
* the type of the reducer.
* @param v The initial value for the reducer. (A value which can be
* assigned to the numeric type represented by @a tn.)
*
* @see @ref reducers_c_predefined
* @see ReducersOr
*/
#define CILK_C_REDUCER_OPOR(obj,tn,v) \
CILK_C_REDUCER_OPOR_TYPE(tn) obj = \
CILK_C_INIT_REDUCER(_Typeof(obj.value), \
__CILKRTS_MKIDENT(cilk_c_reducer_opor_reduce_,tn), \
__CILKRTS_MKIDENT(cilk_c_reducer_opor_identity_,tn), \
__cilkrts_hyperobject_noop_destroy, v)
/// @cond internal
/** Declare the op_or reducer functions for a numeric type.
*
* This macro expands into external function declarations for functions which
* implement the reducer functionality for the op_or reducer type for a
* specified numeric type.
*
* @param t The value type of the reducer.
* @param tn The value “type name” identifier, used to construct the reducer
* type name, function names, etc.
*/
#define CILK_C_REDUCER_OPOR_DECLARATION(t,tn) \
typedef CILK_C_DECLARE_REDUCER(t) CILK_C_REDUCER_OPOR_TYPE(tn); \
__CILKRTS_DECLARE_REDUCER_REDUCE(cilk_c_reducer_opor,tn,l,r); \
__CILKRTS_DECLARE_REDUCER_IDENTITY(cilk_c_reducer_opor,tn);
/** Define the op_or reducer functions for a numeric type.
*
* This macro expands into function definitions for functions which implement
* the reducer functionality for the op_or reducer type for a specified
* numeric type.
*
* @param t The value type of the reducer.
* @param tn The value “type name” identifier, used to construct the reducer
* type name, function names, etc.
*/
#define CILK_C_REDUCER_OPOR_DEFINITION(t,tn) \
typedef CILK_C_DECLARE_REDUCER(t) CILK_C_REDUCER_OPOR_TYPE(tn); \
__CILKRTS_DECLARE_REDUCER_REDUCE(cilk_c_reducer_opor,tn,l,r) \
{ *(t*)l |= *(t*)r; } \
__CILKRTS_DECLARE_REDUCER_IDENTITY(cilk_c_reducer_opor,tn) \
{ *(t*)v = 0; }
//@{
/** @def CILK_C_REDUCER_OPOR_INSTANCE
* @brief Declare or define implementation functions for a reducer type.
*
* In the runtime source file c_reducers.c, the macro `CILK_C_DEFINE_REDUCERS`
* will be defined, and this macro will generate reducer implementation
* functions. Everywhere else, `CILK_C_DEFINE_REDUCERS` will be undefined, and
* this macro will expand into external declarations for the functions.
*/
#ifdef CILK_C_DEFINE_REDUCERS
# define CILK_C_REDUCER_OPOR_INSTANCE(t,tn) \
CILK_C_REDUCER_OPOR_DEFINITION(t,tn)
#else
# define CILK_C_REDUCER_OPOR_INSTANCE(t,tn) \
CILK_C_REDUCER_OPOR_DECLARATION(t,tn)
#endif
//@}
/* Declare or define an instance of the reducer type and its functions for each
* numeric type.
*/
CILK_C_REDUCER_OPOR_INSTANCE(char, char)
CILK_C_REDUCER_OPOR_INSTANCE(unsigned char, uchar)
CILK_C_REDUCER_OPOR_INSTANCE(signed char, schar)
CILK_C_REDUCER_OPOR_INSTANCE(wchar_t, wchar_t)
CILK_C_REDUCER_OPOR_INSTANCE(short, short)
CILK_C_REDUCER_OPOR_INSTANCE(unsigned short, ushort)
CILK_C_REDUCER_OPOR_INSTANCE(int, int)
CILK_C_REDUCER_OPOR_INSTANCE(unsigned int, uint)
CILK_C_REDUCER_OPOR_INSTANCE(unsigned int, unsigned) /* alternate name */
CILK_C_REDUCER_OPOR_INSTANCE(long, long)
CILK_C_REDUCER_OPOR_INSTANCE(unsigned long, ulong)
CILK_C_REDUCER_OPOR_INSTANCE(long long, longlong)
CILK_C_REDUCER_OPOR_INSTANCE(unsigned long long, ulonglong)
//@endcond
__CILKRTS_END_EXTERN_C
//@}
//@}
#endif /* REDUCER_OPOR_H_INCLUDED */