1 /*
2 * Copyright © 2016 Intel Corporation
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining a
5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
7 * the rights to use, copy, modify, merge, publish, distribute, sublicense,
8 * and/or sell copies of the Software, and to permit persons to whom the
9 * Software is furnished to do so, subject to the following conditions:
10 *
11 * The above copyright notice and this permission notice (including the next
12 * paragraph) shall be included in all copies or substantial portions of the
13 * Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
18 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
20 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
21 * DEALINGS IN THE SOFTWARE.
22 */
23
24 /**
25 * \file ir_array_refcount.cpp
26 *
27 * Provides a visitor which produces a list of variables referenced.
28 */
29
30 #include "ir.h"
31 #include "ir_visitor.h"
32 #include "ir_array_refcount.h"
33 #include "compiler/glsl_types.h"
34 #include "util/hash_table.h"
35
ir_array_refcount_visitor()36 ir_array_refcount_visitor::ir_array_refcount_visitor()
37 : last_array_deref(0), derefs(0), num_derefs(0), derefs_size(0)
38 {
39 this->mem_ctx = ralloc_context(NULL);
40 this->ht = _mesa_pointer_hash_table_create(NULL);
41 }
42
43 static void
free_entry(struct hash_entry * entry)44 free_entry(struct hash_entry *entry)
45 {
46 ir_array_refcount_entry *ivre = (ir_array_refcount_entry *) entry->data;
47 delete ivre;
48 }
49
~ir_array_refcount_visitor()50 ir_array_refcount_visitor::~ir_array_refcount_visitor()
51 {
52 ralloc_free(this->mem_ctx);
53 _mesa_hash_table_destroy(this->ht, free_entry);
54 }
55
ir_array_refcount_entry(ir_variable * var)56 ir_array_refcount_entry::ir_array_refcount_entry(ir_variable *var)
57 : var(var), is_referenced(false)
58 {
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]));
62
63 /* Count the "depth" of the arrays-of-arrays. */
64 array_depth = 0;
65 for (const glsl_type *type = var->type;
66 type->is_array();
67 type = type->fields.array) {
68 array_depth++;
69 }
70 }
71
72
~ir_array_refcount_entry()73 ir_array_refcount_entry::~ir_array_refcount_entry()
74 {
75 delete [] bits;
76 }
77
78 ir_array_refcount_entry *
get_variable_entry(ir_variable * var)79 ir_array_refcount_visitor::get_variable_entry(ir_variable *var)
80 {
81 assert(var);
82
83 struct hash_entry *e = _mesa_hash_table_search(this->ht, var);
84 if (e)
85 return (ir_array_refcount_entry *)e->data;
86
87 ir_array_refcount_entry *entry = new ir_array_refcount_entry(var);
88 _mesa_hash_table_insert(this->ht, var, entry);
89
90 return entry;
91 }
92
93
94 array_deref_range *
get_array_deref()95 ir_array_refcount_visitor::get_array_deref()
96 {
97 if ((num_derefs + 1) * sizeof(array_deref_range) > derefs_size) {
98 void *ptr = reralloc_size(mem_ctx, derefs, derefs_size + 4096);
99
100 if (ptr == NULL)
101 return NULL;
102
103 derefs_size += 4096;
104 derefs = (array_deref_range *)ptr;
105 }
106
107 array_deref_range *d = &derefs[num_derefs];
108 num_derefs++;
109
110 return d;
111 }
112
113 ir_visitor_status
visit_enter(ir_dereference_array * ir)114 ir_array_refcount_visitor::visit_enter(ir_dereference_array *ir)
115 {
116 /* It could also be a vector or a matrix. Individual elements of vectors
117 * are natrices are not tracked, so bail.
118 */
119 if (!ir->array->type->is_array())
120 return visit_continue;
121
122 /* If this array dereference is a child of an array dereference that was
123 * already visited, just continue on. Otherwise, for an arrays-of-arrays
124 * dereference like x[1][2][3][4], we'd process the [1][2][3][4] sequence,
125 * the [1][2][3] sequence, the [1][2] sequence, and the [1] sequence. This
126 * ensures that we only process the full sequence.
127 */
128 if (last_array_deref && last_array_deref->array == ir) {
129 last_array_deref = ir;
130 return visit_continue;
131 }
132
133 last_array_deref = ir;
134
135 num_derefs = 0;
136
137 ir_rvalue *rv = ir;
138 while (rv->ir_type == ir_type_dereference_array) {
139 ir_dereference_array *const deref = rv->as_dereference_array();
140
141 assert(deref != NULL);
142 assert(deref->array->type->is_array());
143
144 ir_rvalue *const array = deref->array;
145 const ir_constant *const idx = deref->array_index->as_constant();
146 array_deref_range *const dr = get_array_deref();
147
148 dr->size = array->type->array_size();
149
150 if (idx != NULL) {
151 dr->index = idx->get_int_component(0);
152 } else {
153 /* An unsized array can occur at the end of an SSBO. We can't track
154 * accesses to such an array, so bail.
155 */
156 if (array->type->array_size() == 0)
157 return visit_continue;
158
159 dr->index = dr->size;
160 }
161
162 rv = array;
163 }
164
165 ir_dereference_variable *const var_deref = rv->as_dereference_variable();
166
167 /* If the array being dereferenced is not a variable, bail. At the very
168 * least, ir_constant and ir_dereference_record are possible.
169 */
170 if (var_deref == NULL)
171 return visit_continue;
172
173 ir_array_refcount_entry *const entry =
174 this->get_variable_entry(var_deref->var);
175
176 if (entry == NULL)
177 return visit_stop;
178
179 link_util_mark_array_elements_referenced(derefs, num_derefs,
180 entry->array_depth,
181 entry->bits);
182
183 return visit_continue;
184 }
185
186
187 ir_visitor_status
visit(ir_dereference_variable * ir)188 ir_array_refcount_visitor::visit(ir_dereference_variable *ir)
189 {
190 ir_variable *const var = ir->variable_referenced();
191 ir_array_refcount_entry *entry = this->get_variable_entry(var);
192
193 entry->is_referenced = true;
194
195 return visit_continue;
196 }
197
198
199 ir_visitor_status
visit_enter(ir_function_signature * ir)200 ir_array_refcount_visitor::visit_enter(ir_function_signature *ir)
201 {
202 /* We don't want to descend into the function parameters and
203 * dead-code eliminate them, so just accept the body here.
204 */
205 visit_list_elements(this, &ir->body);
206 return visit_continue_with_parent;
207 }
208