2 * Copyright © 2010 Intel Corporation
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:
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
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.
25 * \file ir_set_program_inouts.cpp
27 * Sets the InputsRead and OutputsWritten of Mesa programs.
29 * Additionally, for fragment shaders, sets the InterpQualifier array, the
30 * IsCentroid and IsSample bitfields, and the UsesDFdy flag.
32 * Mesa programs (gl_program, not gl_shader_program) have a set of
33 * flags indicating which varyings are read and written. Computing
34 * which are actually read from some sort of backend code can be
35 * tricky when variable array indexing involved. So this pass
36 * provides support for setting InputsRead and OutputsWritten right
40 #include "main/core.h" /* for struct gl_program */
42 #include "ir_visitor.h"
43 #include "glsl_types.h"
47 class ir_set_program_inouts_visitor
: public ir_hierarchical_visitor
{
49 ir_set_program_inouts_visitor(struct gl_program
*prog
, GLenum shader_type
)
52 this->shader_type
= shader_type
;
54 ~ir_set_program_inouts_visitor()
58 virtual ir_visitor_status
visit_enter(ir_dereference_array
*);
59 virtual ir_visitor_status
visit_enter(ir_function_signature
*);
60 virtual ir_visitor_status
visit_enter(ir_expression
*);
61 virtual ir_visitor_status
visit_enter(ir_discard
*);
62 virtual ir_visitor_status
visit_enter(ir_texture
*);
63 virtual ir_visitor_status
visit(ir_dereference_variable
*);
66 void mark_whole_variable(ir_variable
*var
);
67 bool try_mark_partial_variable(ir_variable
*var
, ir_rvalue
*index
);
69 struct gl_program
*prog
;
73 } /* anonymous namespace */
76 is_shader_inout(ir_variable
*var
)
78 return var
->data
.mode
== ir_var_shader_in
||
79 var
->data
.mode
== ir_var_shader_out
||
80 var
->data
.mode
== ir_var_system_value
;
84 mark(struct gl_program
*prog
, ir_variable
*var
, int offset
, int len
,
85 bool is_fragment_shader
)
87 /* As of GLSL 1.20, varyings can only be floats, floating-point
88 * vectors or matrices, or arrays of them. For Mesa programs using
89 * InputsRead/OutputsWritten, everything but matrices uses one
90 * slot, while matrices use a slot per column. Presumably
91 * something doing a more clever packing would use something other
92 * than InputsRead/OutputsWritten.
95 for (int i
= 0; i
< len
; i
++) {
96 GLbitfield64 bitfield
=
97 BITFIELD64_BIT(var
->data
.location
+ var
->data
.index
+ offset
+ i
);
98 if (var
->data
.mode
== ir_var_shader_in
) {
99 prog
->InputsRead
|= bitfield
;
100 if (is_fragment_shader
) {
101 gl_fragment_program
*fprog
= (gl_fragment_program
*) prog
;
102 fprog
->InterpQualifier
[var
->data
.location
+
103 var
->data
.index
+ offset
+ i
] =
104 (glsl_interp_qualifier
) var
->data
.interpolation
;
105 if (var
->data
.centroid
)
106 fprog
->IsCentroid
|= bitfield
;
107 if (var
->data
.sample
)
108 fprog
->IsSample
|= bitfield
;
110 } else if (var
->data
.mode
== ir_var_system_value
) {
111 prog
->SystemValuesRead
|= bitfield
;
113 assert(var
->data
.mode
== ir_var_shader_out
);
114 prog
->OutputsWritten
|= bitfield
;
120 * Mark an entire variable as used. Caller must ensure that the variable
121 * represents a shader input or output.
124 ir_set_program_inouts_visitor::mark_whole_variable(ir_variable
*var
)
126 const glsl_type
*type
= var
->type
;
127 if (this->shader_type
== GL_GEOMETRY_SHADER
&&
128 var
->data
.mode
== ir_var_shader_in
&& type
->is_array()) {
129 type
= type
->fields
.array
;
132 mark(this->prog
, var
, 0, type
->count_attribute_slots(),
133 this->shader_type
== GL_FRAGMENT_SHADER
);
136 /* Default handler: Mark all the locations in the variable as used. */
138 ir_set_program_inouts_visitor::visit(ir_dereference_variable
*ir
)
140 if (!is_shader_inout(ir
->var
))
141 return visit_continue
;
143 mark_whole_variable(ir
->var
);
145 return visit_continue
;
149 * Try to mark a portion of the given variable as used. Caller must ensure
150 * that the variable represents a shader input or output which can be indexed
151 * into in array fashion (an array or matrix). For the purpose of geometry
152 * shader inputs (which are always arrays*), this means that the array element
153 * must be something that can be indexed into in array fashion.
155 * *Except gl_PrimitiveIDIn, as noted below.
157 * If the index can't be interpreted as a constant, or some other problem
158 * occurs, then nothing will be marked and false will be returned.
161 ir_set_program_inouts_visitor::try_mark_partial_variable(ir_variable
*var
,
164 const glsl_type
*type
= var
->type
;
166 if (this->shader_type
== GL_GEOMETRY_SHADER
&&
167 var
->data
.mode
== ir_var_shader_in
) {
168 /* The only geometry shader input that is not an array is
169 * gl_PrimitiveIDIn, and in that case, this code will never be reached,
170 * because gl_PrimitiveIDIn can't be indexed into in array fashion.
172 assert(type
->is_array());
173 type
= type
->fields
.array
;
176 /* The code below only handles:
178 * - Indexing into matrices
179 * - Indexing into arrays of (matrices, vectors, or scalars)
181 * All other possibilities are either prohibited by GLSL (vertex inputs and
182 * fragment outputs can't be structs) or should have been eliminated by
183 * lowering passes (do_vec_index_to_swizzle() gets rid of indexing into
184 * vectors, and lower_packed_varyings() gets rid of structs that occur in
187 if (!(type
->is_matrix() ||
189 (type
->fields
.array
->is_numeric() ||
190 type
->fields
.array
->is_boolean())))) {
191 assert(!"Unexpected indexing in ir_set_program_inouts");
193 /* For safety in release builds, in case we ever encounter unexpected
194 * indexing, give up and let the caller mark the whole variable as used.
199 ir_constant
*index_as_constant
= index
->as_constant();
200 if (!index_as_constant
)
205 if (type
->is_array()) {
206 num_elems
= type
->length
;
207 if (type
->fields
.array
->is_matrix())
208 elem_width
= type
->fields
.array
->matrix_columns
;
212 num_elems
= type
->matrix_columns
;
216 if (index_as_constant
->value
.u
[0] >= num_elems
) {
217 /* Constant index outside the bounds of the matrix/array. This could
218 * arise as a result of constant folding of a legal GLSL program.
220 * Even though the spec says that indexing outside the bounds of a
221 * matrix/array results in undefined behaviour, we don't want to pass
222 * out-of-range values to mark() (since this could result in slots that
223 * don't exist being marked as used), so just let the caller mark the
224 * whole variable as used.
229 mark(this->prog
, var
, index_as_constant
->value
.u
[0] * elem_width
,
230 elem_width
, this->shader_type
== GL_FRAGMENT_SHADER
);
235 ir_set_program_inouts_visitor::visit_enter(ir_dereference_array
*ir
)
237 /* Note: for geometry shader inputs, lower_named_interface_blocks may
238 * create 2D arrays, so we need to be able to handle those. 2D arrays
239 * shouldn't be able to crop up for any other reason.
241 if (ir_dereference_array
* const inner_array
=
242 ir
->array
->as_dereference_array()) {
244 * inner_array => foo[i]
246 if (ir_dereference_variable
* const deref_var
=
247 inner_array
->array
->as_dereference_variable()) {
248 if (this->shader_type
== GL_GEOMETRY_SHADER
&&
249 deref_var
->var
->data
.mode
== ir_var_shader_in
) {
250 /* foo is a geometry shader input, so i is the vertex, and j the
251 * part of the input we're accessing.
253 if (try_mark_partial_variable(deref_var
->var
, ir
->array_index
))
255 /* We've now taken care of foo and j, but i might contain a
256 * subexpression that accesses shader inputs. So manually
257 * visit i and then continue with the parent.
259 inner_array
->array_index
->accept(this);
260 return visit_continue_with_parent
;
264 } else if (ir_dereference_variable
* const deref_var
=
265 ir
->array
->as_dereference_variable()) {
266 /* ir => foo[i], where foo is a variable. */
267 if (this->shader_type
== GL_GEOMETRY_SHADER
&&
268 deref_var
->var
->data
.mode
== ir_var_shader_in
) {
269 /* foo is a geometry shader input, so i is the vertex, and we're
270 * accessing the entire input.
272 mark_whole_variable(deref_var
->var
);
273 /* We've now taken care of foo, but i might contain a subexpression
274 * that accesses shader inputs. So manually visit i and then
275 * continue with the parent.
277 ir
->array_index
->accept(this);
278 return visit_continue_with_parent
;
279 } else if (is_shader_inout(deref_var
->var
)) {
280 /* foo is a shader input/output, but not a geometry shader input,
281 * so i is the part of the input we're accessing.
283 if (try_mark_partial_variable(deref_var
->var
, ir
->array_index
))
284 return visit_continue_with_parent
;
288 /* The expression is something we don't recognize. Just visit its
291 return visit_continue
;
295 ir_set_program_inouts_visitor::visit_enter(ir_function_signature
*ir
)
297 /* We don't want to descend into the function parameters and
298 * consider them as shader inputs or outputs.
300 visit_list_elements(this, &ir
->body
);
301 return visit_continue_with_parent
;
305 ir_set_program_inouts_visitor::visit_enter(ir_expression
*ir
)
307 if (this->shader_type
== GL_FRAGMENT_SHADER
&&
308 ir
->operation
== ir_unop_dFdy
) {
309 gl_fragment_program
*fprog
= (gl_fragment_program
*) prog
;
310 fprog
->UsesDFdy
= true;
312 return visit_continue
;
316 ir_set_program_inouts_visitor::visit_enter(ir_discard
*)
318 /* discards are only allowed in fragment shaders. */
319 assert(this->shader_type
== GL_FRAGMENT_SHADER
);
321 gl_fragment_program
*fprog
= (gl_fragment_program
*) prog
;
322 fprog
->UsesKill
= true;
324 return visit_continue
;
328 ir_set_program_inouts_visitor::visit_enter(ir_texture
*ir
)
330 if (ir
->op
== ir_tg4
)
331 prog
->UsesGather
= true;
332 return visit_continue
;
336 do_set_program_inouts(exec_list
*instructions
, struct gl_program
*prog
,
339 ir_set_program_inouts_visitor
v(prog
, shader_type
);
341 prog
->InputsRead
= 0;
342 prog
->OutputsWritten
= 0;
343 prog
->SystemValuesRead
= 0;
344 if (shader_type
== GL_FRAGMENT_SHADER
) {
345 gl_fragment_program
*fprog
= (gl_fragment_program
*) prog
;
346 memset(fprog
->InterpQualifier
, 0, sizeof(fprog
->InterpQualifier
));
347 fprog
->IsCentroid
= 0;
349 fprog
->UsesDFdy
= false;
350 fprog
->UsesKill
= false;
352 visit_list_elements(&v
, instructions
);