Retro68/gcc/libcilkrts/include/cilk/reducer_opand.h
2014-09-21 19:33:12 +02:00

605 lines
22 KiB
C++
Raw Blame History

This file contains ambiguous Unicode characters

This file contains Unicode characters that might be confused with other characters. If you think that this is intentional, you can safely ignore this warning. Use the Escape button to reveal them.

/* reducer_opand.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_opand.h
*
* @brief Defines classes for doing parallel bitwise and reductions.
*
* @ingroup ReducersAnd
*
* @see ReducersAnd
*/
#ifndef REDUCER_OPAND_H_INCLUDED
#define REDUCER_OPAND_H_INCLUDED
#include <cilk/reducer.h>
/** @defgroup ReducersAnd Bitwise And 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 redopand_usage Usage Example
*
* cilk::reducer< cilk::op_and<unsigned> > r;
* cilk_for (int i = 0; i != N; ++i) {
* *r &= a[i];
* }
* unsigned result;
* r.move_out(result);
*
* @section redopand_monoid The Monoid
*
* @subsection redopand_monoid_values Value Set
*
* The value set of a bitwise and 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 redopand_monoid_operator Operator
*
* The operator of a bitwise and reducer is the bitwise and operator, defined
* by the “`&`” binary operator on `Type`.
*
* @subsection redopand_monoid_identity Identity
*
* The identity value of the reducer is the value whose representation
* contains all 1-bits. This is expected to be the value of the expression
* `~Type()` (i.e., the bitwise negation operator applied to the default value
* of the value type).
*
* @section redopand_operations Operations
*
* @subsection redopand_constructors Constructors
*
* reducer() // identity
* reducer(const Type& value)
* reducer(move_in(Type& variable))
*
* @subsection redopand_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 redopand_initial Initial Values
*
* If a bitwise and 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 redopand_types.
*
* @subsection redopand_view_ops View Operations
*
* *r &= a
* *r = *r & a
* *r = *r & a1 & a2 … & an
*
* @section redopand_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
* 1-bits).
*
* @section redopand_in_c Bitwise And Reducers in C
*
* The @ref CILK_C_REDUCER_OPAND and @ref CILK_C_REDUCER_OPAND_TYPE macros can
* be used to do bitwise and reductions in C. For example:
*
* CILK_C_REDUCER_OPAND(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 AND of the elements of a is %x\n", REDUCER_VIEW(r));
*
* See @ref reducers_c_predefined.
*/
#ifdef __cplusplus
namespace cilk {
/** The bitwise and reducer view class.
*
* This is the view class for reducers created with
* `cilk::reducer< cilk::op_and<Type> >`. It holds the accumulator variable
* for the reduction, and allows only `and` 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 ReducersAnd
* @see op_and
*
* @ingroup ReducersAnd
*/
template <typename Type>
class op_and_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_and_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_and_view are
* ones which generate an rhs_proxy — that is, expressions of the form
* `op_and_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_and_view
*/
class rhs_proxy {
private:
friend class op_and_view;
const op_and_view* m_view;
Type m_value;
// Constructor is invoked only from op_and_view::operator&().
//
rhs_proxy(const op_and_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 and with an additional rhs value. If `v` is an op_and_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_and_view() : base(~Type()) {}
/** Construct with a specified initial value.
*/
explicit op_and_view(const Type& v) : base(v) {}
/** Reduction operation.
*
* This function is invoked by the @ref op_and monoid to combine the views
* of two strands when the right strand merges with the left one. It
* “ands” the value contained in the left-strand view with 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_and monoid to implement the monoid
* reduce operation.
*/
void reduce(op_and_view* right) { this->m_value &= right->m_value; }
/** @name Accumulator variable updates.
*
* These functions support the various syntaxes for “anding” the
* accumulator variable contained in the view with some value.
*/
//@{
/** And the accumulator variable with @a x.
*/
op_and_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_and_view& operator=(const rhs_proxy& rhs) {
__CILKRTS_ASSERT(this == rhs.m_view);
this->m_value &= rhs.m_value;
return *this;
}
//@}
};
/** Monoid class for bitwise and reductions. Instantiate the cilk::reducer
* template class with an op_and monoid to create a bitwise and reducer
* class. For example, to compute the bitwise and of a set of `unsigned long`
* values:
*
* cilk::reducer< cilk::op_and<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 ReducersAnd
* @see op_and_view
*
* @ingroup ReducersAnd
*/
template <typename Type, bool Align = false>
struct op_and : public monoid_with_view<op_and_view<Type>, Align> {};
/** Deprecated bitwise and reducer class.
*
* reducer_opand is the same as @ref reducer<@ref op_and>, except that
* reducer_opand 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 anded with a `reducer<%op_and>` with `*r &= a`, but a
* value can be anded with a `%reducer_opand` with `r &= a`.
*
* @deprecated Users are strongly encouraged to use `reducer<monoid>`
* reducers rather than the old wrappers like reducer_opand.
* 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_opand`
* and `reducer<%op_and>`. This allows incremental code
* conversion: old code that used `%reducer_opand` can pass a
* `%reducer_opand` to a converted function that now expects a
* pointer or reference to a `reducer<%op_and>`, and vice
* versa.
*
* @tparam Type The value type of the reducer.
*
* @see op_and
* @see reducer
* @see ReducersAnd
*
* @ingroup ReducersAnd
*/
template <typename Type>
class reducer_opand : public reducer< op_and<Type, true> >
{
typedef reducer< op_and<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 constructor.
*
* Constructs the wrapper with the default initial value of `Type()`
* (not the identity value).
*/
reducer_opand() : base(Type()) {}
/** Value constructor.
*
* Constructs the wrapper with a specified initial value.
*/
explicit reducer_opand(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_and_view::operator&=(const Type&)
reducer_opand& operator&=(const Type& x)
{
view() &= x;
return *this;
}
// The legacy definition of reducer_opand::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_and_view::operator&(const Type&) const
friend rhs_proxy operator&(const reducer_opand& r, const Type& x)
{
return r.view() & x;
}
/// @copydoc op_and_view::operator=(const rhs_proxy&)
reducer_opand& 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_opand& operator*() { return *this; }
reducer_opand const& operator*() const { return *this; }
reducer_opand* operator->() { return this; }
reducer_opand 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_and<Type, false> >& ()
{
return *reinterpret_cast< reducer< op_and<Type, false> >* >(this);
}
operator const reducer< op_and<Type, false> >& () const
{
return *reinterpret_cast< const reducer< op_and<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_and<Type> >` class to have an
* `operator reducer_opand<Type>& ()` conversion operator that statically
* downcasts the `reducer<op_and>` to the corresponding `reducer_opand` type.
* (The reverse conversion, from `reducer_opand` to `reducer<op_and>`, is just
* an upcast, which is provided for free by the language.)
*
* @ingroup ReducersAnd
*/
template <typename Type, bool Align>
struct legacy_reducer_downcast<reducer<op_and<Type, Align> > >
{
typedef reducer_opand<Type> type;
};
/// @endcond
} // namespace cilk
#endif // __cplusplus
/** @ingroup ReducersAdd
*/
//@{
/** @name C language reducer macros
*
* These macros are used to declare and work with op_and reducers in C code.
*
* @see @ref page_reducers_in_c
*/
//@{
__CILKRTS_BEGIN_EXTERN_C
/** Opand reducer type name.
*
* This macro expands into the identifier which is the name of the op_and
* 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 ReducersAnd
*/
#define CILK_C_REDUCER_OPAND_TYPE(tn) \
__CILKRTS_MKIDENT(cilk_c_reducer_opand_,tn)
/** Declare an op_and reducer object.
*
* This macro expands into a declaration of an op_and reducer object for a
* specified numeric type. For example:
*
* CILK_C_REDUCER_OPAND(my_reducer, ulong, ~0UL);
*
* @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 ReducersAnd
*/
#define CILK_C_REDUCER_OPAND(obj,tn,v) \
CILK_C_REDUCER_OPAND_TYPE(tn) obj = \
CILK_C_INIT_REDUCER(_Typeof(obj.value), \
__CILKRTS_MKIDENT(cilk_c_reducer_opand_reduce_,tn), \
__CILKRTS_MKIDENT(cilk_c_reducer_opand_identity_,tn), \
__cilkrts_hyperobject_noop_destroy, v)
/// @cond internal
/** Declare the op_and reducer functions for a numeric type.
*
* This macro expands into external function declarations for functions which
* implement the reducer functionality for the op_and 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_OPAND_DECLARATION(t,tn) \
typedef CILK_C_DECLARE_REDUCER(t) CILK_C_REDUCER_OPAND_TYPE(tn); \
__CILKRTS_DECLARE_REDUCER_REDUCE(cilk_c_reducer_opand,tn,l,r); \
__CILKRTS_DECLARE_REDUCER_IDENTITY(cilk_c_reducer_opand,tn);
/** Define the op_and reducer functions for a numeric type.
*
* This macro expands into function definitions for functions which implement
* the reducer functionality for the op_and 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_OPAND_DEFINITION(t,tn) \
typedef CILK_C_DECLARE_REDUCER(t) CILK_C_REDUCER_OPAND_TYPE(tn); \
__CILKRTS_DECLARE_REDUCER_REDUCE(cilk_c_reducer_opand,tn,l,r) \
{ *(t*)l &= *(t*)r; } \
__CILKRTS_DECLARE_REDUCER_IDENTITY(cilk_c_reducer_opand,tn) \
{ *(t*)v = ~((t)0); }
//@{
/** @def CILK_C_REDUCER_OPAND_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_OPAND_INSTANCE(t,tn) \
CILK_C_REDUCER_OPAND_DEFINITION(t,tn)
#else
# define CILK_C_REDUCER_OPAND_INSTANCE(t,tn) \
CILK_C_REDUCER_OPAND_DECLARATION(t,tn)
#endif
//@}
/* Declare or define an instance of the reducer type and its functions for
* each numeric type.
*/
CILK_C_REDUCER_OPAND_INSTANCE(char, char)
CILK_C_REDUCER_OPAND_INSTANCE(unsigned char, uchar)
CILK_C_REDUCER_OPAND_INSTANCE(signed char, schar)
CILK_C_REDUCER_OPAND_INSTANCE(wchar_t, wchar_t)
CILK_C_REDUCER_OPAND_INSTANCE(short, short)
CILK_C_REDUCER_OPAND_INSTANCE(unsigned short, ushort)
CILK_C_REDUCER_OPAND_INSTANCE(int, int)
CILK_C_REDUCER_OPAND_INSTANCE(unsigned int, uint)
CILK_C_REDUCER_OPAND_INSTANCE(unsigned int, unsigned) /* alternate name */
CILK_C_REDUCER_OPAND_INSTANCE(long, long)
CILK_C_REDUCER_OPAND_INSTANCE(unsigned long, ulong)
CILK_C_REDUCER_OPAND_INSTANCE(long long, longlong)
CILK_C_REDUCER_OPAND_INSTANCE(unsigned long long, ulonglong)
//@endcond
__CILKRTS_END_EXTERN_C
//@}
//@}
#endif /* REDUCER_OPAND_H_INCLUDED */