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/*
* Copyright © 2016 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
/**
* \file ir_array_refcount.h
*
* Provides a visitor which produces a list of variables referenced.
*/
#include "ir.h"
#include "ir_visitor.h"
#include "compiler/glsl_types.h"
#include "util/bitset.h"
/**
* Describes an access of an array element or an access of the whole array
*/
struct array_deref_range {
/**
* Index that was accessed.
*
* All valid array indices are less than the size of the array. If index
* is equal to the size of the array, this means the entire array has been
* accessed (e.g., due to use of a non-constant index).
*/
unsigned index;
/** Size of the array. Used for offset calculations. */
unsigned size;
};
class ir_array_refcount_entry
{
public:
ir_array_refcount_entry(ir_variable *var);
~ir_array_refcount_entry();
ir_variable *var; /* The key: the variable's pointer. */
/** Has the variable been referenced? */
bool is_referenced;
/**
* Mark a set of array elements as accessed.
*
* If every \c array_deref_range is for a single index, only a single
* element will be marked. If any \c array_deref_range is for an entire
* array-of-, then multiple elements will be marked.
*
* Items in the \c array_deref_range list appear in least- to
* most-significant order. This is the \b opposite order the indices
* appear in the GLSL shader text. An array access like
*
* x = y[1][i][3];
*
* would appear as
*
* { { 3, n }, { m, m }, { 1, p } }
*
* where n, m, and p are the sizes of the arrays-of-arrays.
*
* The set of marked array elements can later be queried by
* \c ::is_linearized_index_referenced.
*
* \param dr List of array_deref_range elements to be processed.
* \param count Number of array_deref_range elements to be processed.
*/
void mark_array_elements_referenced(const array_deref_range *dr,
unsigned count);
/** Has a linearized array index been referenced? */
bool is_linearized_index_referenced(unsigned linearized_index) const
{
assert(bits != 0);
assert(linearized_index <= num_bits);
return BITSET_TEST(bits, linearized_index);
}
private:
/** Set of bit-flags to note which array elements have been accessed. */
BITSET_WORD *bits;
/**
* Total number of bits referenced by \c bits.
*
* Also the total number of array(s-of-arrays) elements of \c var.
*/
unsigned num_bits;
/** Count of nested arrays in the type. */
unsigned array_depth;
/**
* Recursive part of the public mark_array_elements_referenced method.
*
* The recursion occurs when an entire array-of- is accessed. See the
* implementation for more details.
*
* \param dr List of array_deref_range elements to be
* processed.
* \param count Number of array_deref_range elements to be
* processed.
* \param scale Current offset scale.
* \param linearized_index Current accumulated linearized array index.
*/
void mark_array_elements_referenced(const array_deref_range *dr,
unsigned count,
unsigned scale,
unsigned linearized_index);
friend class array_refcount_test;
};
class ir_array_refcount_visitor : public ir_hierarchical_visitor {
public:
ir_array_refcount_visitor(void);
~ir_array_refcount_visitor(void);
virtual ir_visitor_status visit(ir_dereference_variable *);
virtual ir_visitor_status visit_enter(ir_function_signature *);
virtual ir_visitor_status visit_enter(ir_dereference_array *);
/**
* Find variable in the hash table, and insert it if not present
*/
ir_array_refcount_entry *get_variable_entry(ir_variable *var);
/**
* Hash table mapping ir_variable to ir_array_refcount_entry.
*/
struct hash_table *ht;
void *mem_ctx;
private:
/** Get an array_deref_range element from private tracking. */
array_deref_range *get_array_deref();
/**
* Last ir_dereference_array that was visited
*
* Used to prevent some redundant calculations.
*
* \sa ::visit_enter(ir_dereference_array *)
*/
ir_dereference_array *last_array_deref;
/**
* \name array_deref_range tracking
*/
/*@{*/
/** Currently allocated block of derefs. */
array_deref_range *derefs;
/** Number of derefs used in current processing. */
unsigned num_derefs;
/** Size of the derefs buffer in bytes. */
unsigned derefs_size;
/*@}*/
};
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