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25 * \file ir_array_refcount.cpp
27 * Provides a visitor which produces a list of variables referenced.
31 #include "ir_visitor.h"
32 #include "ir_array_refcount.h"
33 #include "compiler/glsl_types.h"
34 #include "util/hash_table.h"
36 ir_array_refcount_visitor::ir_array_refcount_visitor()
37 : last_array_deref(0), derefs(0), num_derefs(0), derefs_size(0)
39 this->mem_ctx
= ralloc_context(NULL
);
40 this->ht
= _mesa_pointer_hash_table_create(NULL
);
44 free_entry(struct hash_entry
*entry
)
46 ir_array_refcount_entry
*ivre
= (ir_array_refcount_entry
*) entry
->data
;
50 ir_array_refcount_visitor::~ir_array_refcount_visitor()
52 ralloc_free(this->mem_ctx
);
53 _mesa_hash_table_destroy(this->ht
, free_entry
);
56 ir_array_refcount_entry::ir_array_refcount_entry(ir_variable
*var
)
57 : var(var
), is_referenced(false)
59 num_bits
= MAX2(1, var
->type
->arrays_of_arrays_size());
60 bits
= new BITSET_WORD
[BITSET_WORDS(num_bits
)];
61 memset(bits
, 0, BITSET_WORDS(num_bits
) * sizeof(bits
[0]));
63 /* Count the "depth" of the arrays-of-arrays. */
65 for (const glsl_type
*type
= var
->type
;
67 type
= type
->fields
.array
) {
73 ir_array_refcount_entry::~ir_array_refcount_entry()
80 ir_array_refcount_entry::mark_array_elements_referenced(const array_deref_range
*dr
,
83 if (count
!= array_depth
)
86 mark_array_elements_referenced(dr
, count
, 1, 0);
90 ir_array_refcount_entry::mark_array_elements_referenced(const array_deref_range
*dr
,
93 unsigned linearized_index
)
95 /* Walk through the list of array dereferences in least- to
96 * most-significant order. Along the way, accumulate the current
97 * linearized offset and the scale factor for each array-of-.
99 for (unsigned i
= 0; i
< count
; i
++) {
100 if (dr
[i
].index
< dr
[i
].size
) {
101 linearized_index
+= dr
[i
].index
* scale
;
104 /* For each element in the current array, update the count and
105 * offset, then recurse to process the remaining arrays.
107 * There is some inefficency here if the last element in the
108 * array_deref_range list specifies the entire array. In that case,
109 * the loop will make recursive calls with count == 0. In the call,
110 * all that will happen is the bit will be set.
112 for (unsigned j
= 0; j
< dr
[i
].size
; j
++) {
113 mark_array_elements_referenced(&dr
[i
+ 1],
116 linearized_index
+ (j
* scale
));
123 BITSET_SET(bits
, linearized_index
);
126 ir_array_refcount_entry
*
127 ir_array_refcount_visitor::get_variable_entry(ir_variable
*var
)
131 struct hash_entry
*e
= _mesa_hash_table_search(this->ht
, var
);
133 return (ir_array_refcount_entry
*)e
->data
;
135 ir_array_refcount_entry
*entry
= new ir_array_refcount_entry(var
);
136 _mesa_hash_table_insert(this->ht
, var
, entry
);
143 ir_array_refcount_visitor::get_array_deref()
145 if ((num_derefs
+ 1) * sizeof(array_deref_range
) > derefs_size
) {
146 void *ptr
= reralloc_size(mem_ctx
, derefs
, derefs_size
+ 4096);
152 derefs
= (array_deref_range
*)ptr
;
155 array_deref_range
*d
= &derefs
[num_derefs
];
162 ir_array_refcount_visitor::visit_enter(ir_dereference_array
*ir
)
164 /* It could also be a vector or a matrix. Individual elements of vectors
165 * are natrices are not tracked, so bail.
167 if (!ir
->array
->type
->is_array())
168 return visit_continue
;
170 /* If this array dereference is a child of an array dereference that was
171 * already visited, just continue on. Otherwise, for an arrays-of-arrays
172 * dereference like x[1][2][3][4], we'd process the [1][2][3][4] sequence,
173 * the [1][2][3] sequence, the [1][2] sequence, and the [1] sequence. This
174 * ensures that we only process the full sequence.
176 if (last_array_deref
&& last_array_deref
->array
== ir
) {
177 last_array_deref
= ir
;
178 return visit_continue
;
181 last_array_deref
= ir
;
186 while (rv
->ir_type
== ir_type_dereference_array
) {
187 ir_dereference_array
*const deref
= rv
->as_dereference_array();
189 assert(deref
!= NULL
);
190 assert(deref
->array
->type
->is_array());
192 ir_rvalue
*const array
= deref
->array
;
193 const ir_constant
*const idx
= deref
->array_index
->as_constant();
194 array_deref_range
*const dr
= get_array_deref();
196 dr
->size
= array
->type
->array_size();
199 dr
->index
= idx
->get_int_component(0);
201 /* An unsized array can occur at the end of an SSBO. We can't track
202 * accesses to such an array, so bail.
204 if (array
->type
->array_size() == 0)
205 return visit_continue
;
207 dr
->index
= dr
->size
;
213 ir_dereference_variable
*const var_deref
= rv
->as_dereference_variable();
215 /* If the array being dereferenced is not a variable, bail. At the very
216 * least, ir_constant and ir_dereference_record are possible.
218 if (var_deref
== NULL
)
219 return visit_continue
;
221 ir_array_refcount_entry
*const entry
=
222 this->get_variable_entry(var_deref
->var
);
227 entry
->mark_array_elements_referenced(derefs
, num_derefs
);
229 return visit_continue
;
234 ir_array_refcount_visitor::visit(ir_dereference_variable
*ir
)
236 ir_variable
*const var
= ir
->variable_referenced();
237 ir_array_refcount_entry
*entry
= this->get_variable_entry(var
);
239 entry
->is_referenced
= true;
241 return visit_continue
;
246 ir_array_refcount_visitor::visit_enter(ir_function_signature
*ir
)
248 /* We don't want to descend into the function parameters and
249 * dead-code eliminate them, so just accept the body here.
251 visit_list_elements(this, &ir
->body
);
252 return visit_continue_with_parent
;