Merge remote-tracking branch 'mesa-public/master' into vulkan
[mesa.git] / src / glsl / ast_array_index.cpp
1 /*
2 * Copyright © 2010 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 #include "ast.h"
25 #include "glsl_types.h"
26 #include "ir.h"
27
28 void
29 ast_array_specifier::print(void) const
30 {
31 if (this->is_unsized_array) {
32 printf("[ ] ");
33 }
34
35 foreach_list_typed (ast_node, array_dimension, link, &this->array_dimensions) {
36 printf("[ ");
37 array_dimension->print();
38 printf("] ");
39 }
40 }
41
42 /**
43 * If \c ir is a reference to an array for which we are tracking the max array
44 * element accessed, track that the given element has been accessed.
45 * Otherwise do nothing.
46 *
47 * This function also checks whether the array is a built-in array whose
48 * maximum size is too small to accommodate the given index, and if so uses
49 * loc and state to report the error.
50 */
51 static void
52 update_max_array_access(ir_rvalue *ir, int idx, YYLTYPE *loc,
53 struct _mesa_glsl_parse_state *state)
54 {
55 if (ir_dereference_variable *deref_var = ir->as_dereference_variable()) {
56 ir_variable *var = deref_var->var;
57 if (idx > (int)var->data.max_array_access) {
58 var->data.max_array_access = idx;
59
60 /* Check whether this access will, as a side effect, implicitly cause
61 * the size of a built-in array to be too large.
62 */
63 check_builtin_array_max_size(var->name, idx+1, *loc, state);
64 }
65 } else if (ir_dereference_record *deref_record =
66 ir->as_dereference_record()) {
67 /* There are two possibilities we need to consider:
68 *
69 * - Accessing an element of an array that is a member of a named
70 * interface block (e.g. ifc.foo[i])
71 *
72 * - Accessing an element of an array that is a member of a named
73 * interface block array (e.g. ifc[j].foo[i]).
74 */
75 ir_dereference_variable *deref_var =
76 deref_record->record->as_dereference_variable();
77 if (deref_var == NULL) {
78 if (ir_dereference_array *deref_array =
79 deref_record->record->as_dereference_array()) {
80 deref_var = deref_array->array->as_dereference_variable();
81 }
82 }
83
84 if (deref_var != NULL) {
85 if (deref_var->var->is_interface_instance()) {
86 unsigned field_index =
87 deref_record->record->type->field_index(deref_record->field);
88 assert(field_index < deref_var->var->get_interface_type()->length);
89
90 unsigned *const max_ifc_array_access =
91 deref_var->var->get_max_ifc_array_access();
92
93 assert(max_ifc_array_access != NULL);
94
95 if (idx > (int)max_ifc_array_access[field_index]) {
96 max_ifc_array_access[field_index] = idx;
97
98 /* Check whether this access will, as a side effect, implicitly
99 * cause the size of a built-in array to be too large.
100 */
101 check_builtin_array_max_size(deref_record->field, idx+1, *loc,
102 state);
103 }
104 }
105 }
106 }
107 }
108
109
110 static int
111 get_implicit_array_size(struct _mesa_glsl_parse_state *state,
112 ir_rvalue *array)
113 {
114 ir_variable *var = array->variable_referenced();
115
116 /* Inputs in control shader are implicitly sized
117 * to the maximum patch size.
118 */
119 if (state->stage == MESA_SHADER_TESS_CTRL &&
120 var->data.mode == ir_var_shader_in) {
121 return state->Const.MaxPatchVertices;
122 }
123
124 /* Non-patch inputs in evaluation shader are implicitly sized
125 * to the maximum patch size.
126 */
127 if (state->stage == MESA_SHADER_TESS_EVAL &&
128 var->data.mode == ir_var_shader_in &&
129 !var->data.patch) {
130 return state->Const.MaxPatchVertices;
131 }
132
133 return 0;
134 }
135
136
137 ir_rvalue *
138 _mesa_ast_array_index_to_hir(void *mem_ctx,
139 struct _mesa_glsl_parse_state *state,
140 ir_rvalue *array, ir_rvalue *idx,
141 YYLTYPE &loc, YYLTYPE &idx_loc)
142 {
143 if (!array->type->is_error()
144 && !array->type->is_array()
145 && !array->type->is_matrix()
146 && !array->type->is_vector()) {
147 _mesa_glsl_error(& idx_loc, state,
148 "cannot dereference non-array / non-matrix / "
149 "non-vector");
150 }
151
152 if (!idx->type->is_error()) {
153 if (!idx->type->is_integer()) {
154 _mesa_glsl_error(& idx_loc, state, "array index must be integer type");
155 } else if (!idx->type->is_scalar()) {
156 _mesa_glsl_error(& idx_loc, state, "array index must be scalar");
157 }
158 }
159
160 /* If the array index is a constant expression and the array has a
161 * declared size, ensure that the access is in-bounds. If the array
162 * index is not a constant expression, ensure that the array has a
163 * declared size.
164 */
165 ir_constant *const const_index = idx->constant_expression_value();
166 if (const_index != NULL && idx->type->is_integer()) {
167 const int idx = const_index->value.i[0];
168 const char *type_name = "error";
169 unsigned bound = 0;
170
171 /* From page 24 (page 30 of the PDF) of the GLSL 1.50 spec:
172 *
173 * "It is illegal to declare an array with a size, and then
174 * later (in the same shader) index the same array with an
175 * integral constant expression greater than or equal to the
176 * declared size. It is also illegal to index an array with a
177 * negative constant expression."
178 */
179 if (array->type->is_matrix()) {
180 if (array->type->row_type()->vector_elements <= idx) {
181 type_name = "matrix";
182 bound = array->type->row_type()->vector_elements;
183 }
184 } else if (array->type->is_vector()) {
185 if (array->type->vector_elements <= idx) {
186 type_name = "vector";
187 bound = array->type->vector_elements;
188 }
189 } else {
190 /* glsl_type::array_size() returns -1 for non-array types. This means
191 * that we don't need to verify that the type is an array before
192 * doing the bounds checking.
193 */
194 if ((array->type->array_size() > 0)
195 && (array->type->array_size() <= idx)) {
196 type_name = "array";
197 bound = array->type->array_size();
198 }
199 }
200
201 if (bound > 0) {
202 _mesa_glsl_error(& loc, state, "%s index must be < %u",
203 type_name, bound);
204 } else if (idx < 0) {
205 _mesa_glsl_error(& loc, state, "%s index must be >= 0",
206 type_name);
207 }
208
209 if (array->type->is_array())
210 update_max_array_access(array, idx, &loc, state);
211 } else if (const_index == NULL && array->type->is_array()) {
212 if (array->type->is_unsized_array()) {
213 int implicit_size = get_implicit_array_size(state, array);
214 if (implicit_size) {
215 ir_variable *v = array->whole_variable_referenced();
216 if (v != NULL)
217 v->data.max_array_access = implicit_size - 1;
218 }
219 else if (state->stage == MESA_SHADER_TESS_CTRL &&
220 array->variable_referenced()->data.mode == ir_var_shader_out &&
221 !array->variable_referenced()->data.patch) {
222 /* Tessellation control shader output non-patch arrays are
223 * initially unsized. Despite that, they are allowed to be
224 * indexed with a non-constant expression (typically
225 * "gl_InvocationID"). The array size will be determined
226 * by the linker.
227 */
228 }
229 else {
230 _mesa_glsl_error(&loc, state, "unsized array index must be constant");
231 }
232 } else if (array->type->fields.array->is_interface()
233 && array->variable_referenced()->data.mode == ir_var_uniform
234 && !state->is_version(400, 0) && !state->ARB_gpu_shader5_enable) {
235 /* Page 46 in section 4.3.7 of the OpenGL ES 3.00 spec says:
236 *
237 * "All indexes used to index a uniform block array must be
238 * constant integral expressions."
239 */
240 _mesa_glsl_error(&loc, state,
241 "uniform block array index must be constant");
242 } else {
243 /* whole_variable_referenced can return NULL if the array is a
244 * member of a structure. In this case it is safe to not update
245 * the max_array_access field because it is never used for fields
246 * of structures.
247 */
248 ir_variable *v = array->whole_variable_referenced();
249 if (v != NULL)
250 v->data.max_array_access = array->type->array_size() - 1;
251 }
252
253 /* From page 23 (29 of the PDF) of the GLSL 1.30 spec:
254 *
255 * "Samplers aggregated into arrays within a shader (using square
256 * brackets [ ]) can only be indexed with integral constant
257 * expressions [...]."
258 *
259 * This restriction was added in GLSL 1.30. Shaders using earlier
260 * version of the language should not be rejected by the compiler
261 * front-end for using this construct. This allows useful things such
262 * as using a loop counter as the index to an array of samplers. If the
263 * loop in unrolled, the code should compile correctly. Instead, emit a
264 * warning.
265 *
266 * In GLSL 4.00 / ARB_gpu_shader5, this requirement is relaxed again to allow
267 * indexing with dynamically uniform expressions. Note that these are not
268 * required to be uniforms or expressions based on them, but merely that the
269 * values must not diverge between shader invocations run together. If the
270 * values *do* diverge, then the behavior of the operation requiring a
271 * dynamically uniform expression is undefined.
272 */
273 if (array->type->without_array()->is_sampler()) {
274 if (!state->is_version(400, 0) && !state->ARB_gpu_shader5_enable) {
275 if (state->is_version(130, 300))
276 _mesa_glsl_error(&loc, state,
277 "sampler arrays indexed with non-constant "
278 "expressions are forbidden in GLSL %s "
279 "and later",
280 state->es_shader ? "ES 3.00" : "1.30");
281 else if (state->es_shader)
282 _mesa_glsl_warning(&loc, state,
283 "sampler arrays indexed with non-constant "
284 "expressions will be forbidden in GLSL "
285 "3.00 and later");
286 else
287 _mesa_glsl_warning(&loc, state,
288 "sampler arrays indexed with non-constant "
289 "expressions will be forbidden in GLSL "
290 "1.30 and later");
291 }
292 }
293
294 /* From page 27 of the GLSL ES 3.1 specification:
295 *
296 * "When aggregated into arrays within a shader, images can only be
297 * indexed with a constant integral expression."
298 *
299 * On the other hand the desktop GL specification extension allows
300 * non-constant indexing of image arrays, but behavior is left undefined
301 * in cases where the indexing expression is not dynamically uniform.
302 */
303 if (state->es_shader && array->type->without_array()->is_image()) {
304 _mesa_glsl_error(&loc, state,
305 "image arrays indexed with non-constant "
306 "expressions are forbidden in GLSL ES.");
307 }
308 }
309
310 /* After performing all of the error checking, generate the IR for the
311 * expression.
312 */
313 if (array->type->is_array()
314 || array->type->is_matrix()) {
315 return new(mem_ctx) ir_dereference_array(array, idx);
316 } else if (array->type->is_vector()) {
317 return new(mem_ctx) ir_expression(ir_binop_vector_extract, array, idx);
318 } else if (array->type->is_error()) {
319 return array;
320 } else {
321 ir_rvalue *result = new(mem_ctx) ir_dereference_array(array, idx);
322 result->type = glsl_type::error_type;
323
324 return result;
325 }
326 }