2 * Copyright © 2012 Intel Corporation
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5 * copy of this software and associated documentation files (the "Software"),
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16 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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21 * DEALINGS IN THE SOFTWARE.
25 * \file link_varyings.cpp
27 * Linker functions related specifically to linking varyings between shader
32 #include "main/mtypes.h"
33 #include "glsl_symbol_table.h"
34 #include "glsl_parser_extras.h"
35 #include "ir_optimization.h"
37 #include "link_varyings.h"
38 #include "main/macros.h"
39 #include "program/hash_table.h"
44 * Validate the types and qualifiers of an output from one stage against the
45 * matching input to another stage.
48 cross_validate_types_and_qualifiers(struct gl_shader_program
*prog
,
49 const ir_variable
*input
,
50 const ir_variable
*output
,
51 gl_shader_stage consumer_stage
,
52 gl_shader_stage producer_stage
)
54 /* Check that the types match between stages.
56 const glsl_type
*type_to_match
= input
->type
;
57 if (consumer_stage
== MESA_SHADER_GEOMETRY
) {
58 assert(type_to_match
->is_array()); /* Enforced by ast_to_hir */
59 type_to_match
= type_to_match
->element_type();
61 if (type_to_match
!= output
->type
) {
62 /* There is a bit of a special case for gl_TexCoord. This
63 * built-in is unsized by default. Applications that variable
64 * access it must redeclare it with a size. There is some
65 * language in the GLSL spec that implies the fragment shader
66 * and vertex shader do not have to agree on this size. Other
67 * driver behave this way, and one or two applications seem to
70 * Neither declaration needs to be modified here because the array
71 * sizes are fixed later when update_array_sizes is called.
73 * From page 48 (page 54 of the PDF) of the GLSL 1.10 spec:
75 * "Unlike user-defined varying variables, the built-in
76 * varying variables don't have a strict one-to-one
77 * correspondence between the vertex language and the
80 if (!output
->type
->is_array() || !is_gl_identifier(output
->name
)) {
82 "%s shader output `%s' declared as type `%s', "
83 "but %s shader input declared as type `%s'\n",
84 _mesa_shader_stage_to_string(producer_stage
),
87 _mesa_shader_stage_to_string(consumer_stage
),
93 /* Check that all of the qualifiers match between stages.
95 if (input
->data
.centroid
!= output
->data
.centroid
) {
97 "%s shader output `%s' %s centroid qualifier, "
98 "but %s shader input %s centroid qualifier\n",
99 _mesa_shader_stage_to_string(producer_stage
),
101 (output
->data
.centroid
) ? "has" : "lacks",
102 _mesa_shader_stage_to_string(consumer_stage
),
103 (input
->data
.centroid
) ? "has" : "lacks");
107 if (input
->data
.sample
!= output
->data
.sample
) {
109 "%s shader output `%s' %s sample qualifier, "
110 "but %s shader input %s sample qualifier\n",
111 _mesa_shader_stage_to_string(producer_stage
),
113 (output
->data
.sample
) ? "has" : "lacks",
114 _mesa_shader_stage_to_string(consumer_stage
),
115 (input
->data
.sample
) ? "has" : "lacks");
119 if (input
->data
.invariant
!= output
->data
.invariant
) {
121 "%s shader output `%s' %s invariant qualifier, "
122 "but %s shader input %s invariant qualifier\n",
123 _mesa_shader_stage_to_string(producer_stage
),
125 (output
->data
.invariant
) ? "has" : "lacks",
126 _mesa_shader_stage_to_string(consumer_stage
),
127 (input
->data
.invariant
) ? "has" : "lacks");
131 if (input
->data
.interpolation
!= output
->data
.interpolation
) {
133 "%s shader output `%s' specifies %s "
134 "interpolation qualifier, "
135 "but %s shader input specifies %s "
136 "interpolation qualifier\n",
137 _mesa_shader_stage_to_string(producer_stage
),
139 interpolation_string(output
->data
.interpolation
),
140 _mesa_shader_stage_to_string(consumer_stage
),
141 interpolation_string(input
->data
.interpolation
));
147 * Validate front and back color outputs against single color input
150 cross_validate_front_and_back_color(struct gl_shader_program
*prog
,
151 const ir_variable
*input
,
152 const ir_variable
*front_color
,
153 const ir_variable
*back_color
,
154 gl_shader_stage consumer_stage
,
155 gl_shader_stage producer_stage
)
157 if (front_color
!= NULL
&& front_color
->data
.assigned
)
158 cross_validate_types_and_qualifiers(prog
, input
, front_color
,
159 consumer_stage
, producer_stage
);
161 if (back_color
!= NULL
&& back_color
->data
.assigned
)
162 cross_validate_types_and_qualifiers(prog
, input
, back_color
,
163 consumer_stage
, producer_stage
);
167 * Validate that outputs from one stage match inputs of another
170 cross_validate_outputs_to_inputs(struct gl_shader_program
*prog
,
171 gl_shader
*producer
, gl_shader
*consumer
)
173 glsl_symbol_table parameters
;
174 ir_variable
*explicit_locations
[MAX_VARYING
] = { NULL
, };
176 /* Find all shader outputs in the "producer" stage.
178 foreach_list(node
, producer
->ir
) {
179 ir_variable
*const var
= ((ir_instruction
*) node
)->as_variable();
181 if ((var
== NULL
) || (var
->data
.mode
!= ir_var_shader_out
))
184 if (!var
->data
.explicit_location
185 || var
->data
.location
< VARYING_SLOT_VAR0
)
186 parameters
.add_variable(var
);
188 /* User-defined varyings with explicit locations are handled
189 * differently because they do not need to have matching names.
191 const unsigned idx
= var
->data
.location
- VARYING_SLOT_VAR0
;
193 if (explicit_locations
[idx
] != NULL
) {
195 "%s shader has multiple outputs explicitly "
196 "assigned to location %d\n",
197 _mesa_shader_stage_to_string(producer
->Stage
),
202 explicit_locations
[idx
] = var
;
207 /* Find all shader inputs in the "consumer" stage. Any variables that have
208 * matching outputs already in the symbol table must have the same type and
211 * Exception: if the consumer is the geometry shader, then the inputs
212 * should be arrays and the type of the array element should match the type
213 * of the corresponding producer output.
215 foreach_list(node
, consumer
->ir
) {
216 ir_variable
*const input
= ((ir_instruction
*) node
)->as_variable();
218 if ((input
== NULL
) || (input
->data
.mode
!= ir_var_shader_in
))
221 if (strcmp(input
->name
, "gl_Color") == 0 && input
->data
.used
) {
222 const ir_variable
*const front_color
=
223 parameters
.get_variable("gl_FrontColor");
225 const ir_variable
*const back_color
=
226 parameters
.get_variable("gl_BackColor");
228 cross_validate_front_and_back_color(prog
, input
,
229 front_color
, back_color
,
230 consumer
->Stage
, producer
->Stage
);
231 } else if (strcmp(input
->name
, "gl_SecondaryColor") == 0 && input
->data
.used
) {
232 const ir_variable
*const front_color
=
233 parameters
.get_variable("gl_FrontSecondaryColor");
235 const ir_variable
*const back_color
=
236 parameters
.get_variable("gl_BackSecondaryColor");
238 cross_validate_front_and_back_color(prog
, input
,
239 front_color
, back_color
,
240 consumer
->Stage
, producer
->Stage
);
242 /* The rules for connecting inputs and outputs change in the presence
243 * of explicit locations. In this case, we no longer care about the
244 * names of the variables. Instead, we care only about the
245 * explicitly assigned location.
247 ir_variable
*output
= NULL
;
248 if (input
->data
.explicit_location
249 && input
->data
.location
>= VARYING_SLOT_VAR0
) {
250 output
= explicit_locations
[input
->data
.location
- VARYING_SLOT_VAR0
];
252 if (output
== NULL
) {
254 "%s shader input `%s' with explicit location "
255 "has no matching output\n",
256 _mesa_shader_stage_to_string(consumer
->Stage
),
260 output
= parameters
.get_variable(input
->name
);
263 if (output
!= NULL
) {
264 cross_validate_types_and_qualifiers(prog
, input
, output
,
265 consumer
->Stage
, producer
->Stage
);
273 * Initialize this object based on a string that was passed to
274 * glTransformFeedbackVaryings.
276 * If the input is mal-formed, this call still succeeds, but it sets
277 * this->var_name to a mal-formed input, so tfeedback_decl::find_output_var()
278 * will fail to find any matching variable.
281 tfeedback_decl::init(struct gl_context
*ctx
, const void *mem_ctx
,
284 /* We don't have to be pedantic about what is a valid GLSL variable name,
285 * because any variable with an invalid name can't exist in the IR anyway.
289 this->orig_name
= input
;
290 this->is_clip_distance_mesa
= false;
291 this->skip_components
= 0;
292 this->next_buffer_separator
= false;
293 this->matched_candidate
= NULL
;
296 if (ctx
->Extensions
.ARB_transform_feedback3
) {
297 /* Parse gl_NextBuffer. */
298 if (strcmp(input
, "gl_NextBuffer") == 0) {
299 this->next_buffer_separator
= true;
303 /* Parse gl_SkipComponents. */
304 if (strcmp(input
, "gl_SkipComponents1") == 0)
305 this->skip_components
= 1;
306 else if (strcmp(input
, "gl_SkipComponents2") == 0)
307 this->skip_components
= 2;
308 else if (strcmp(input
, "gl_SkipComponents3") == 0)
309 this->skip_components
= 3;
310 else if (strcmp(input
, "gl_SkipComponents4") == 0)
311 this->skip_components
= 4;
313 if (this->skip_components
)
317 /* Parse a declaration. */
318 const char *base_name_end
;
319 long subscript
= parse_program_resource_name(input
, &base_name_end
);
320 this->var_name
= ralloc_strndup(mem_ctx
, input
, base_name_end
- input
);
321 if (subscript
>= 0) {
322 this->array_subscript
= subscript
;
323 this->is_subscripted
= true;
325 this->is_subscripted
= false;
328 /* For drivers that lower gl_ClipDistance to gl_ClipDistanceMESA, this
329 * class must behave specially to account for the fact that gl_ClipDistance
330 * is converted from a float[8] to a vec4[2].
332 if (ctx
->ShaderCompilerOptions
[MESA_SHADER_VERTEX
].LowerClipDistance
&&
333 strcmp(this->var_name
, "gl_ClipDistance") == 0) {
334 this->is_clip_distance_mesa
= true;
340 * Determine whether two tfeedback_decl objects refer to the same variable and
341 * array index (if applicable).
344 tfeedback_decl::is_same(const tfeedback_decl
&x
, const tfeedback_decl
&y
)
346 assert(x
.is_varying() && y
.is_varying());
348 if (strcmp(x
.var_name
, y
.var_name
) != 0)
350 if (x
.is_subscripted
!= y
.is_subscripted
)
352 if (x
.is_subscripted
&& x
.array_subscript
!= y
.array_subscript
)
359 * Assign a location and stream ID for this tfeedback_decl object based on the
360 * transform feedback candidate found by find_candidate.
362 * If an error occurs, the error is reported through linker_error() and false
366 tfeedback_decl::assign_location(struct gl_context
*ctx
,
367 struct gl_shader_program
*prog
)
369 assert(this->is_varying());
371 unsigned fine_location
372 = this->matched_candidate
->toplevel_var
->data
.location
* 4
373 + this->matched_candidate
->toplevel_var
->data
.location_frac
374 + this->matched_candidate
->offset
;
376 if (this->matched_candidate
->type
->is_array()) {
378 const unsigned matrix_cols
=
379 this->matched_candidate
->type
->fields
.array
->matrix_columns
;
380 const unsigned vector_elements
=
381 this->matched_candidate
->type
->fields
.array
->vector_elements
;
382 unsigned actual_array_size
= this->is_clip_distance_mesa
?
383 prog
->LastClipDistanceArraySize
:
384 this->matched_candidate
->type
->array_size();
386 if (this->is_subscripted
) {
387 /* Check array bounds. */
388 if (this->array_subscript
>= actual_array_size
) {
389 linker_error(prog
, "Transform feedback varying %s has index "
390 "%i, but the array size is %u.",
391 this->orig_name
, this->array_subscript
,
395 unsigned array_elem_size
= this->is_clip_distance_mesa
?
396 1 : vector_elements
* matrix_cols
;
397 fine_location
+= array_elem_size
* this->array_subscript
;
400 this->size
= actual_array_size
;
402 this->vector_elements
= vector_elements
;
403 this->matrix_columns
= matrix_cols
;
404 if (this->is_clip_distance_mesa
)
405 this->type
= GL_FLOAT
;
407 this->type
= this->matched_candidate
->type
->fields
.array
->gl_type
;
409 /* Regular variable (scalar, vector, or matrix) */
410 if (this->is_subscripted
) {
411 linker_error(prog
, "Transform feedback varying %s requested, "
412 "but %s is not an array.",
413 this->orig_name
, this->var_name
);
417 this->vector_elements
= this->matched_candidate
->type
->vector_elements
;
418 this->matrix_columns
= this->matched_candidate
->type
->matrix_columns
;
419 this->type
= this->matched_candidate
->type
->gl_type
;
421 this->location
= fine_location
/ 4;
422 this->location_frac
= fine_location
% 4;
424 /* From GL_EXT_transform_feedback:
425 * A program will fail to link if:
427 * * the total number of components to capture in any varying
428 * variable in <varyings> is greater than the constant
429 * MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS_EXT and the
430 * buffer mode is SEPARATE_ATTRIBS_EXT;
432 if (prog
->TransformFeedback
.BufferMode
== GL_SEPARATE_ATTRIBS
&&
433 this->num_components() >
434 ctx
->Const
.MaxTransformFeedbackSeparateComponents
) {
435 linker_error(prog
, "Transform feedback varying %s exceeds "
436 "MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS.",
441 /* Only transform feedback varyings can be assigned to non-zero streams,
442 * so assign the stream id here.
444 this->stream_id
= this->matched_candidate
->toplevel_var
->data
.stream
;
451 tfeedback_decl::get_num_outputs() const
453 if (!this->is_varying()) {
457 return (this->num_components() + this->location_frac
+ 3)/4;
462 * Update gl_transform_feedback_info to reflect this tfeedback_decl.
464 * If an error occurs, the error is reported through linker_error() and false
468 tfeedback_decl::store(struct gl_context
*ctx
, struct gl_shader_program
*prog
,
469 struct gl_transform_feedback_info
*info
,
470 unsigned buffer
, const unsigned max_outputs
) const
472 assert(!this->next_buffer_separator
);
474 /* Handle gl_SkipComponents. */
475 if (this->skip_components
) {
476 info
->BufferStride
[buffer
] += this->skip_components
;
480 /* From GL_EXT_transform_feedback:
481 * A program will fail to link if:
483 * * the total number of components to capture is greater than
484 * the constant MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS_EXT
485 * and the buffer mode is INTERLEAVED_ATTRIBS_EXT.
487 if (prog
->TransformFeedback
.BufferMode
== GL_INTERLEAVED_ATTRIBS
&&
488 info
->BufferStride
[buffer
] + this->num_components() >
489 ctx
->Const
.MaxTransformFeedbackInterleavedComponents
) {
490 linker_error(prog
, "The MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS "
491 "limit has been exceeded.");
495 unsigned location
= this->location
;
496 unsigned location_frac
= this->location_frac
;
497 unsigned num_components
= this->num_components();
498 while (num_components
> 0) {
499 unsigned output_size
= MIN2(num_components
, 4 - location_frac
);
500 assert(info
->NumOutputs
< max_outputs
);
501 info
->Outputs
[info
->NumOutputs
].ComponentOffset
= location_frac
;
502 info
->Outputs
[info
->NumOutputs
].OutputRegister
= location
;
503 info
->Outputs
[info
->NumOutputs
].NumComponents
= output_size
;
504 info
->Outputs
[info
->NumOutputs
].StreamId
= stream_id
;
505 info
->Outputs
[info
->NumOutputs
].OutputBuffer
= buffer
;
506 info
->Outputs
[info
->NumOutputs
].DstOffset
= info
->BufferStride
[buffer
];
508 info
->BufferStride
[buffer
] += output_size
;
509 num_components
-= output_size
;
514 info
->Varyings
[info
->NumVarying
].Name
= ralloc_strdup(prog
, this->orig_name
);
515 info
->Varyings
[info
->NumVarying
].Type
= this->type
;
516 info
->Varyings
[info
->NumVarying
].Size
= this->size
;
523 const tfeedback_candidate
*
524 tfeedback_decl::find_candidate(gl_shader_program
*prog
,
525 hash_table
*tfeedback_candidates
)
527 const char *name
= this->is_clip_distance_mesa
528 ? "gl_ClipDistanceMESA" : this->var_name
;
529 this->matched_candidate
= (const tfeedback_candidate
*)
530 hash_table_find(tfeedback_candidates
, name
);
531 if (!this->matched_candidate
) {
532 /* From GL_EXT_transform_feedback:
533 * A program will fail to link if:
535 * * any variable name specified in the <varyings> array is not
536 * declared as an output in the geometry shader (if present) or
537 * the vertex shader (if no geometry shader is present);
539 linker_error(prog
, "Transform feedback varying %s undeclared.",
542 return this->matched_candidate
;
547 * Parse all the transform feedback declarations that were passed to
548 * glTransformFeedbackVaryings() and store them in tfeedback_decl objects.
550 * If an error occurs, the error is reported through linker_error() and false
554 parse_tfeedback_decls(struct gl_context
*ctx
, struct gl_shader_program
*prog
,
555 const void *mem_ctx
, unsigned num_names
,
556 char **varying_names
, tfeedback_decl
*decls
)
558 for (unsigned i
= 0; i
< num_names
; ++i
) {
559 decls
[i
].init(ctx
, mem_ctx
, varying_names
[i
]);
561 if (!decls
[i
].is_varying())
564 /* From GL_EXT_transform_feedback:
565 * A program will fail to link if:
567 * * any two entries in the <varyings> array specify the same varying
570 * We interpret this to mean "any two entries in the <varyings> array
571 * specify the same varying variable and array index", since transform
572 * feedback of arrays would be useless otherwise.
574 for (unsigned j
= 0; j
< i
; ++j
) {
575 if (!decls
[j
].is_varying())
578 if (tfeedback_decl::is_same(decls
[i
], decls
[j
])) {
579 linker_error(prog
, "Transform feedback varying %s specified "
580 "more than once.", varying_names
[i
]);
590 * Store transform feedback location assignments into
591 * prog->LinkedTransformFeedback based on the data stored in tfeedback_decls.
593 * If an error occurs, the error is reported through linker_error() and false
597 store_tfeedback_info(struct gl_context
*ctx
, struct gl_shader_program
*prog
,
598 unsigned num_tfeedback_decls
,
599 tfeedback_decl
*tfeedback_decls
)
601 bool separate_attribs_mode
=
602 prog
->TransformFeedback
.BufferMode
== GL_SEPARATE_ATTRIBS
;
604 ralloc_free(prog
->LinkedTransformFeedback
.Varyings
);
605 ralloc_free(prog
->LinkedTransformFeedback
.Outputs
);
607 memset(&prog
->LinkedTransformFeedback
, 0,
608 sizeof(prog
->LinkedTransformFeedback
));
610 prog
->LinkedTransformFeedback
.Varyings
=
612 struct gl_transform_feedback_varying_info
,
613 num_tfeedback_decls
);
615 unsigned num_outputs
= 0;
616 for (unsigned i
= 0; i
< num_tfeedback_decls
; ++i
)
617 num_outputs
+= tfeedback_decls
[i
].get_num_outputs();
619 prog
->LinkedTransformFeedback
.Outputs
=
621 struct gl_transform_feedback_output
,
624 unsigned num_buffers
= 0;
626 if (separate_attribs_mode
) {
627 /* GL_SEPARATE_ATTRIBS */
628 for (unsigned i
= 0; i
< num_tfeedback_decls
; ++i
) {
629 if (!tfeedback_decls
[i
].store(ctx
, prog
, &prog
->LinkedTransformFeedback
,
630 num_buffers
, num_outputs
))
637 /* GL_INVERLEAVED_ATTRIBS */
638 for (unsigned i
= 0; i
< num_tfeedback_decls
; ++i
) {
639 if (tfeedback_decls
[i
].is_next_buffer_separator()) {
644 if (!tfeedback_decls
[i
].store(ctx
, prog
,
645 &prog
->LinkedTransformFeedback
,
646 num_buffers
, num_outputs
))
652 assert(prog
->LinkedTransformFeedback
.NumOutputs
== num_outputs
);
654 prog
->LinkedTransformFeedback
.NumBuffers
= num_buffers
;
661 * Data structure recording the relationship between outputs of one shader
662 * stage (the "producer") and inputs of another (the "consumer").
664 class varying_matches
667 varying_matches(bool disable_varying_packing
, bool consumer_is_fs
);
669 void record(ir_variable
*producer_var
, ir_variable
*consumer_var
);
670 unsigned assign_locations();
671 void store_locations() const;
675 * If true, this driver disables varying packing, so all varyings need to
676 * be aligned on slot boundaries, and take up a number of slots equal to
677 * their number of matrix columns times their array size.
679 const bool disable_varying_packing
;
682 * Enum representing the order in which varyings are packed within a
685 * Currently we pack vec4's first, then vec2's, then scalar values, then
686 * vec3's. This order ensures that the only vectors that are at risk of
687 * having to be "double parked" (split between two adjacent varying slots)
690 enum packing_order_enum
{
693 PACKING_ORDER_SCALAR
,
697 static unsigned compute_packing_class(const ir_variable
*var
);
698 static packing_order_enum
compute_packing_order(const ir_variable
*var
);
699 static int match_comparator(const void *x_generic
, const void *y_generic
);
702 * Structure recording the relationship between a single producer output
703 * and a single consumer input.
707 * Packing class for this varying, computed by compute_packing_class().
709 unsigned packing_class
;
712 * Packing order for this varying, computed by compute_packing_order().
714 packing_order_enum packing_order
;
715 unsigned num_components
;
718 * The output variable in the producer stage.
720 ir_variable
*producer_var
;
723 * The input variable in the consumer stage.
725 ir_variable
*consumer_var
;
728 * The location which has been assigned for this varying. This is
729 * expressed in multiples of a float, with the first generic varying
730 * (i.e. the one referred to by VARYING_SLOT_VAR0) represented by the
733 unsigned generic_location
;
737 * The number of elements in the \c matches array that are currently in
740 unsigned num_matches
;
743 * The number of elements that were set aside for the \c matches array when
746 unsigned matches_capacity
;
748 const bool consumer_is_fs
;
751 } /* anonymous namespace */
753 varying_matches::varying_matches(bool disable_varying_packing
,
755 : disable_varying_packing(disable_varying_packing
),
756 consumer_is_fs(consumer_is_fs
)
758 /* Note: this initial capacity is rather arbitrarily chosen to be large
759 * enough for many cases without wasting an unreasonable amount of space.
760 * varying_matches::record() will resize the array if there are more than
761 * this number of varyings.
763 this->matches_capacity
= 8;
764 this->matches
= (match
*)
765 malloc(sizeof(*this->matches
) * this->matches_capacity
);
766 this->num_matches
= 0;
770 varying_matches::~varying_matches()
777 * Record the given producer/consumer variable pair in the list of variables
778 * that should later be assigned locations.
780 * It is permissible for \c consumer_var to be NULL (this happens if a
781 * variable is output by the producer and consumed by transform feedback, but
782 * not consumed by the consumer).
784 * If \c producer_var has already been paired up with a consumer_var, or
785 * producer_var is part of fixed pipeline functionality (and hence already has
786 * a location assigned), this function has no effect.
788 * Note: as a side effect this function may change the interpolation type of
789 * \c producer_var, but only when the change couldn't possibly affect
793 varying_matches::record(ir_variable
*producer_var
, ir_variable
*consumer_var
)
795 assert(producer_var
!= NULL
|| consumer_var
!= NULL
);
797 if ((producer_var
&& !producer_var
->data
.is_unmatched_generic_inout
)
798 || (consumer_var
&& !consumer_var
->data
.is_unmatched_generic_inout
)) {
799 /* Either a location already exists for this variable (since it is part
800 * of fixed functionality), or it has already been recorded as part of a
806 if ((consumer_var
== NULL
&& producer_var
->type
->contains_integer()) ||
808 /* Since this varying is not being consumed by the fragment shader, its
809 * interpolation type varying cannot possibly affect rendering. Also,
810 * this variable is non-flat and is (or contains) an integer.
812 * lower_packed_varyings requires all integer varyings to flat,
813 * regardless of where they appear. We can trivially satisfy that
814 * requirement by changing the interpolation type to flat here.
816 producer_var
->data
.centroid
= false;
817 producer_var
->data
.sample
= false;
818 producer_var
->data
.interpolation
= INTERP_QUALIFIER_FLAT
;
821 consumer_var
->data
.centroid
= false;
822 consumer_var
->data
.sample
= false;
823 consumer_var
->data
.interpolation
= INTERP_QUALIFIER_FLAT
;
827 if (this->num_matches
== this->matches_capacity
) {
828 this->matches_capacity
*= 2;
829 this->matches
= (match
*)
830 realloc(this->matches
,
831 sizeof(*this->matches
) * this->matches_capacity
);
834 const ir_variable
*const var
= (producer_var
!= NULL
)
835 ? producer_var
: consumer_var
;
837 this->matches
[this->num_matches
].packing_class
838 = this->compute_packing_class(var
);
839 this->matches
[this->num_matches
].packing_order
840 = this->compute_packing_order(var
);
841 if (this->disable_varying_packing
) {
842 unsigned slots
= var
->type
->is_array()
843 ? (var
->type
->length
* var
->type
->fields
.array
->matrix_columns
)
844 : var
->type
->matrix_columns
;
845 this->matches
[this->num_matches
].num_components
= 4 * slots
;
847 this->matches
[this->num_matches
].num_components
848 = var
->type
->component_slots();
850 this->matches
[this->num_matches
].producer_var
= producer_var
;
851 this->matches
[this->num_matches
].consumer_var
= consumer_var
;
854 producer_var
->data
.is_unmatched_generic_inout
= 0;
856 consumer_var
->data
.is_unmatched_generic_inout
= 0;
861 * Choose locations for all of the variable matches that were previously
862 * passed to varying_matches::record().
865 varying_matches::assign_locations()
867 /* Sort varying matches into an order that makes them easy to pack. */
868 qsort(this->matches
, this->num_matches
, sizeof(*this->matches
),
869 &varying_matches::match_comparator
);
871 unsigned generic_location
= 0;
873 for (unsigned i
= 0; i
< this->num_matches
; i
++) {
874 /* Advance to the next slot if this varying has a different packing
875 * class than the previous one, and we're not already on a slot
879 this->matches
[i
- 1].packing_class
880 != this->matches
[i
].packing_class
) {
881 generic_location
= ALIGN(generic_location
, 4);
884 this->matches
[i
].generic_location
= generic_location
;
886 generic_location
+= this->matches
[i
].num_components
;
889 return (generic_location
+ 3) / 4;
894 * Update the producer and consumer shaders to reflect the locations
895 * assignments that were made by varying_matches::assign_locations().
898 varying_matches::store_locations() const
900 for (unsigned i
= 0; i
< this->num_matches
; i
++) {
901 ir_variable
*producer_var
= this->matches
[i
].producer_var
;
902 ir_variable
*consumer_var
= this->matches
[i
].consumer_var
;
903 unsigned generic_location
= this->matches
[i
].generic_location
;
904 unsigned slot
= generic_location
/ 4;
905 unsigned offset
= generic_location
% 4;
908 producer_var
->data
.location
= VARYING_SLOT_VAR0
+ slot
;
909 producer_var
->data
.location_frac
= offset
;
913 assert(consumer_var
->data
.location
== -1);
914 consumer_var
->data
.location
= VARYING_SLOT_VAR0
+ slot
;
915 consumer_var
->data
.location_frac
= offset
;
922 * Compute the "packing class" of the given varying. This is an unsigned
923 * integer with the property that two variables in the same packing class can
924 * be safely backed into the same vec4.
927 varying_matches::compute_packing_class(const ir_variable
*var
)
929 /* Without help from the back-end, there is no way to pack together
930 * variables with different interpolation types, because
931 * lower_packed_varyings must choose exactly one interpolation type for
932 * each packed varying it creates.
934 * However, we can safely pack together floats, ints, and uints, because:
936 * - varyings of base type "int" and "uint" must use the "flat"
937 * interpolation type, which can only occur in GLSL 1.30 and above.
939 * - On platforms that support GLSL 1.30 and above, lower_packed_varyings
940 * can store flat floats as ints without losing any information (using
941 * the ir_unop_bitcast_* opcodes).
943 * Therefore, the packing class depends only on the interpolation type.
945 unsigned packing_class
= var
->data
.centroid
| (var
->data
.sample
<< 1);
947 packing_class
+= var
->data
.interpolation
;
948 return packing_class
;
953 * Compute the "packing order" of the given varying. This is a sort key we
954 * use to determine when to attempt to pack the given varying relative to
955 * other varyings in the same packing class.
957 varying_matches::packing_order_enum
958 varying_matches::compute_packing_order(const ir_variable
*var
)
960 const glsl_type
*element_type
= var
->type
;
962 while (element_type
->base_type
== GLSL_TYPE_ARRAY
) {
963 element_type
= element_type
->fields
.array
;
966 switch (element_type
->component_slots() % 4) {
967 case 1: return PACKING_ORDER_SCALAR
;
968 case 2: return PACKING_ORDER_VEC2
;
969 case 3: return PACKING_ORDER_VEC3
;
970 case 0: return PACKING_ORDER_VEC4
;
972 assert(!"Unexpected value of vector_elements");
973 return PACKING_ORDER_VEC4
;
979 * Comparison function passed to qsort() to sort varyings by packing_class and
980 * then by packing_order.
983 varying_matches::match_comparator(const void *x_generic
, const void *y_generic
)
985 const match
*x
= (const match
*) x_generic
;
986 const match
*y
= (const match
*) y_generic
;
988 if (x
->packing_class
!= y
->packing_class
)
989 return x
->packing_class
- y
->packing_class
;
990 return x
->packing_order
- y
->packing_order
;
995 * Is the given variable a varying variable to be counted against the
996 * limit in ctx->Const.MaxVarying?
997 * This includes variables such as texcoords, colors and generic
998 * varyings, but excludes variables such as gl_FrontFacing and gl_FragCoord.
1001 var_counts_against_varying_limit(gl_shader_stage stage
, const ir_variable
*var
)
1003 /* Only fragment shaders will take a varying variable as an input */
1004 if (stage
== MESA_SHADER_FRAGMENT
&&
1005 var
->data
.mode
== ir_var_shader_in
) {
1006 switch (var
->data
.location
) {
1007 case VARYING_SLOT_POS
:
1008 case VARYING_SLOT_FACE
:
1009 case VARYING_SLOT_PNTC
:
1020 * Visitor class that generates tfeedback_candidate structs describing all
1021 * possible targets of transform feedback.
1023 * tfeedback_candidate structs are stored in the hash table
1024 * tfeedback_candidates, which is passed to the constructor. This hash table
1025 * maps varying names to instances of the tfeedback_candidate struct.
1027 class tfeedback_candidate_generator
: public program_resource_visitor
1030 tfeedback_candidate_generator(void *mem_ctx
,
1031 hash_table
*tfeedback_candidates
)
1033 tfeedback_candidates(tfeedback_candidates
),
1039 void process(ir_variable
*var
)
1041 this->toplevel_var
= var
;
1042 this->varying_floats
= 0;
1043 if (var
->is_interface_instance())
1044 program_resource_visitor::process(var
->get_interface_type(),
1045 var
->get_interface_type()->name
);
1047 program_resource_visitor::process(var
);
1051 virtual void visit_field(const glsl_type
*type
, const char *name
,
1054 assert(!type
->is_record());
1055 assert(!(type
->is_array() && type
->fields
.array
->is_record()));
1056 assert(!type
->is_interface());
1057 assert(!(type
->is_array() && type
->fields
.array
->is_interface()));
1061 tfeedback_candidate
*candidate
1062 = rzalloc(this->mem_ctx
, tfeedback_candidate
);
1063 candidate
->toplevel_var
= this->toplevel_var
;
1064 candidate
->type
= type
;
1065 candidate
->offset
= this->varying_floats
;
1066 hash_table_insert(this->tfeedback_candidates
, candidate
,
1067 ralloc_strdup(this->mem_ctx
, name
));
1068 this->varying_floats
+= type
->component_slots();
1072 * Memory context used to allocate hash table keys and values.
1074 void * const mem_ctx
;
1077 * Hash table in which tfeedback_candidate objects should be stored.
1079 hash_table
* const tfeedback_candidates
;
1082 * Pointer to the toplevel variable that is being traversed.
1084 ir_variable
*toplevel_var
;
1087 * Total number of varying floats that have been visited so far. This is
1088 * used to determine the offset to each varying within the toplevel
1091 unsigned varying_floats
;
1098 populate_consumer_input_sets(void *mem_ctx
, exec_list
*ir
,
1099 hash_table
*consumer_inputs
,
1100 hash_table
*consumer_interface_inputs
,
1101 ir_variable
*consumer_inputs_with_locations
[VARYING_SLOT_MAX
])
1103 memset(consumer_inputs_with_locations
,
1105 sizeof(consumer_inputs_with_locations
[0]) * VARYING_SLOT_MAX
);
1107 foreach_list(node
, ir
) {
1108 ir_variable
*const input_var
= ((ir_instruction
*) node
)->as_variable();
1110 if ((input_var
!= NULL
) && (input_var
->data
.mode
== ir_var_shader_in
)) {
1111 if (input_var
->type
->is_interface())
1114 if (input_var
->data
.explicit_location
) {
1115 /* assign_varying_locations only cares about finding the
1116 * ir_variable at the start of a contiguous location block.
1118 * - For !producer, consumer_inputs_with_locations isn't used.
1120 * - For !consumer, consumer_inputs_with_locations is empty.
1122 * For consumer && producer, if you were trying to set some
1123 * ir_variable to the middle of a location block on the other side
1124 * of producer/consumer, cross_validate_outputs_to_inputs() should
1125 * be link-erroring due to either type mismatch or location
1126 * overlaps. If the variables do match up, then they've got a
1127 * matching data.location and you only looked at
1128 * consumer_inputs_with_locations[var->data.location], not any
1129 * following entries for the array/structure.
1131 consumer_inputs_with_locations
[input_var
->data
.location
] =
1133 } else if (input_var
->get_interface_type() != NULL
) {
1134 char *const iface_field_name
=
1135 ralloc_asprintf(mem_ctx
, "%s.%s",
1136 input_var
->get_interface_type()->name
,
1138 hash_table_insert(consumer_interface_inputs
, input_var
,
1141 hash_table_insert(consumer_inputs
, input_var
,
1142 ralloc_strdup(mem_ctx
, input_var
->name
));
1151 * Find a variable from the consumer that "matches" the specified variable
1153 * This function only finds inputs with names that match. There is no
1154 * validation (here) that the types, etc. are compatible.
1157 get_matching_input(void *mem_ctx
,
1158 const ir_variable
*output_var
,
1159 hash_table
*consumer_inputs
,
1160 hash_table
*consumer_interface_inputs
,
1161 ir_variable
*consumer_inputs_with_locations
[VARYING_SLOT_MAX
])
1163 ir_variable
*input_var
;
1165 if (output_var
->data
.explicit_location
) {
1166 input_var
= consumer_inputs_with_locations
[output_var
->data
.location
];
1167 } else if (output_var
->get_interface_type() != NULL
) {
1168 char *const iface_field_name
=
1169 ralloc_asprintf(mem_ctx
, "%s.%s",
1170 output_var
->get_interface_type()->name
,
1173 (ir_variable
*) hash_table_find(consumer_interface_inputs
,
1177 (ir_variable
*) hash_table_find(consumer_inputs
, output_var
->name
);
1180 return (input_var
== NULL
|| input_var
->data
.mode
!= ir_var_shader_in
)
1187 io_variable_cmp(const void *_a
, const void *_b
)
1189 const ir_variable
*const a
= *(const ir_variable
**) _a
;
1190 const ir_variable
*const b
= *(const ir_variable
**) _b
;
1192 if (a
->data
.explicit_location
&& b
->data
.explicit_location
)
1193 return b
->data
.location
- a
->data
.location
;
1195 if (a
->data
.explicit_location
&& !b
->data
.explicit_location
)
1198 if (!a
->data
.explicit_location
&& b
->data
.explicit_location
)
1201 return -strcmp(a
->name
, b
->name
);
1205 * Sort the shader IO variables into canonical order
1208 canonicalize_shader_io(exec_list
*ir
, enum ir_variable_mode io_mode
)
1210 ir_variable
*var_table
[MAX_PROGRAM_OUTPUTS
* 4];
1211 unsigned num_variables
= 0;
1213 foreach_list(node
, ir
) {
1214 ir_variable
*const var
= ((ir_instruction
*) node
)->as_variable();
1216 if (var
== NULL
|| var
->data
.mode
!= io_mode
)
1219 /* If we have already encountered more I/O variables that could
1220 * successfully link, bail.
1222 if (num_variables
== ARRAY_SIZE(var_table
))
1225 var_table
[num_variables
++] = var
;
1228 if (num_variables
== 0)
1231 /* Sort the list in reverse order (io_variable_cmp handles this). Later
1232 * we're going to push the variables on to the IR list as a stack, so we
1233 * want the last variable (in canonical order) to be first in the list.
1235 qsort(var_table
, num_variables
, sizeof(var_table
[0]), io_variable_cmp
);
1237 /* Remove the variable from it's current location in the IR, and put it at
1240 for (unsigned i
= 0; i
< num_variables
; i
++) {
1241 var_table
[i
]->remove();
1242 ir
->push_head(var_table
[i
]);
1247 * Assign locations for all variables that are produced in one pipeline stage
1248 * (the "producer") and consumed in the next stage (the "consumer").
1250 * Variables produced by the producer may also be consumed by transform
1253 * \param num_tfeedback_decls is the number of declarations indicating
1254 * variables that may be consumed by transform feedback.
1256 * \param tfeedback_decls is a pointer to an array of tfeedback_decl objects
1257 * representing the result of parsing the strings passed to
1258 * glTransformFeedbackVaryings(). assign_location() will be called for
1259 * each of these objects that matches one of the outputs of the
1262 * \param gs_input_vertices: if \c consumer is a geometry shader, this is the
1263 * number of input vertices it accepts. Otherwise zero.
1265 * When num_tfeedback_decls is nonzero, it is permissible for the consumer to
1266 * be NULL. In this case, varying locations are assigned solely based on the
1267 * requirements of transform feedback.
1270 assign_varying_locations(struct gl_context
*ctx
,
1272 struct gl_shader_program
*prog
,
1273 gl_shader
*producer
, gl_shader
*consumer
,
1274 unsigned num_tfeedback_decls
,
1275 tfeedback_decl
*tfeedback_decls
,
1276 unsigned gs_input_vertices
)
1278 varying_matches
matches(ctx
->Const
.DisableVaryingPacking
,
1279 consumer
&& consumer
->Stage
== MESA_SHADER_FRAGMENT
);
1280 hash_table
*tfeedback_candidates
1281 = hash_table_ctor(0, hash_table_string_hash
, hash_table_string_compare
);
1282 hash_table
*consumer_inputs
1283 = hash_table_ctor(0, hash_table_string_hash
, hash_table_string_compare
);
1284 hash_table
*consumer_interface_inputs
1285 = hash_table_ctor(0, hash_table_string_hash
, hash_table_string_compare
);
1286 ir_variable
*consumer_inputs_with_locations
[VARYING_SLOT_MAX
] = {
1290 /* Operate in a total of four passes.
1292 * 1. Sort inputs / outputs into a canonical order. This is necessary so
1293 * that inputs / outputs of separable shaders will be assigned
1294 * predictable locations regardless of the order in which declarations
1295 * appeared in the shader source.
1297 * 2. Assign locations for any matching inputs and outputs.
1299 * 3. Mark output variables in the producer that do not have locations as
1300 * not being outputs. This lets the optimizer eliminate them.
1302 * 4. Mark input variables in the consumer that do not have locations as
1303 * not being inputs. This lets the optimizer eliminate them.
1306 canonicalize_shader_io(consumer
->ir
, ir_var_shader_in
);
1309 canonicalize_shader_io(producer
->ir
, ir_var_shader_out
);
1312 && !linker::populate_consumer_input_sets(mem_ctx
,
1315 consumer_interface_inputs
,
1316 consumer_inputs_with_locations
)) {
1317 assert(!"populate_consumer_input_sets failed");
1318 hash_table_dtor(tfeedback_candidates
);
1319 hash_table_dtor(consumer_inputs
);
1320 hash_table_dtor(consumer_interface_inputs
);
1325 foreach_list(node
, producer
->ir
) {
1326 ir_variable
*const output_var
=
1327 ((ir_instruction
*) node
)->as_variable();
1329 if ((output_var
== NULL
) ||
1330 (output_var
->data
.mode
!= ir_var_shader_out
))
1333 tfeedback_candidate_generator
g(mem_ctx
, tfeedback_candidates
);
1334 g
.process(output_var
);
1336 ir_variable
*const input_var
=
1337 linker::get_matching_input(mem_ctx
, output_var
, consumer_inputs
,
1338 consumer_interface_inputs
,
1339 consumer_inputs_with_locations
);
1341 /* If a matching input variable was found, add this ouptut (and the
1342 * input) to the set. If this is a separable program and there is no
1343 * consumer stage, add the output.
1345 if (input_var
|| (prog
->SeparateShader
&& consumer
== NULL
)) {
1346 matches
.record(output_var
, input_var
);
1349 /* Only stream 0 outputs can be consumed in the next stage */
1350 if (input_var
&& output_var
->data
.stream
!= 0) {
1351 linker_error(prog
, "output %s is assigned to stream=%d but "
1352 "is linked to an input, which requires stream=0",
1353 output_var
->name
, output_var
->data
.stream
);
1358 /* If there's no producer stage, then this must be a separable program.
1359 * For example, we may have a program that has just a fragment shader.
1360 * Later this program will be used with some arbitrary vertex (or
1361 * geometry) shader program. This means that locations must be assigned
1362 * for all the inputs.
1364 foreach_list(node
, consumer
->ir
) {
1365 ir_variable
*const input_var
=
1366 ((ir_instruction
*) node
)->as_variable();
1368 if ((input_var
== NULL
) ||
1369 (input_var
->data
.mode
!= ir_var_shader_in
))
1372 matches
.record(NULL
, input_var
);
1376 for (unsigned i
= 0; i
< num_tfeedback_decls
; ++i
) {
1377 if (!tfeedback_decls
[i
].is_varying())
1380 const tfeedback_candidate
*matched_candidate
1381 = tfeedback_decls
[i
].find_candidate(prog
, tfeedback_candidates
);
1383 if (matched_candidate
== NULL
) {
1384 hash_table_dtor(tfeedback_candidates
);
1385 hash_table_dtor(consumer_inputs
);
1386 hash_table_dtor(consumer_interface_inputs
);
1390 if (matched_candidate
->toplevel_var
->data
.is_unmatched_generic_inout
)
1391 matches
.record(matched_candidate
->toplevel_var
, NULL
);
1394 const unsigned slots_used
= matches
.assign_locations();
1395 matches
.store_locations();
1397 for (unsigned i
= 0; i
< num_tfeedback_decls
; ++i
) {
1398 if (!tfeedback_decls
[i
].is_varying())
1401 if (!tfeedback_decls
[i
].assign_location(ctx
, prog
)) {
1402 hash_table_dtor(tfeedback_candidates
);
1403 hash_table_dtor(consumer_inputs
);
1404 hash_table_dtor(consumer_interface_inputs
);
1409 hash_table_dtor(tfeedback_candidates
);
1410 hash_table_dtor(consumer_inputs
);
1411 hash_table_dtor(consumer_interface_inputs
);
1413 if (ctx
->Const
.DisableVaryingPacking
) {
1414 /* Transform feedback code assumes varyings are packed, so if the driver
1415 * has disabled varying packing, make sure it does not support transform
1418 assert(!ctx
->Extensions
.EXT_transform_feedback
);
1421 lower_packed_varyings(mem_ctx
, slots_used
, ir_var_shader_out
,
1425 lower_packed_varyings(mem_ctx
, slots_used
, ir_var_shader_in
,
1426 gs_input_vertices
, consumer
);
1430 if (consumer
&& producer
) {
1431 foreach_list(node
, consumer
->ir
) {
1432 ir_variable
*const var
= ((ir_instruction
*) node
)->as_variable();
1434 if (var
&& var
->data
.mode
== ir_var_shader_in
&&
1435 var
->data
.is_unmatched_generic_inout
) {
1436 if (prog
->Version
<= 120) {
1437 /* On page 25 (page 31 of the PDF) of the GLSL 1.20 spec:
1439 * Only those varying variables used (i.e. read) in
1440 * the fragment shader executable must be written to
1441 * by the vertex shader executable; declaring
1442 * superfluous varying variables in a vertex shader is
1445 * We interpret this text as meaning that the VS must
1446 * write the variable for the FS to read it. See
1447 * "glsl1-varying read but not written" in piglit.
1450 linker_error(prog
, "%s shader varying %s not written "
1452 _mesa_shader_stage_to_string(consumer
->Stage
),
1454 _mesa_shader_stage_to_string(producer
->Stage
));
1457 /* An 'in' variable is only really a shader input if its
1458 * value is written by the previous stage.
1460 var
->data
.mode
= ir_var_auto
;
1469 check_against_output_limit(struct gl_context
*ctx
,
1470 struct gl_shader_program
*prog
,
1471 gl_shader
*producer
)
1473 unsigned output_vectors
= 0;
1475 foreach_list(node
, producer
->ir
) {
1476 ir_variable
*const var
= ((ir_instruction
*) node
)->as_variable();
1478 if (var
&& var
->data
.mode
== ir_var_shader_out
&&
1479 var_counts_against_varying_limit(producer
->Stage
, var
)) {
1480 output_vectors
+= var
->type
->count_attribute_slots();
1484 assert(producer
->Stage
!= MESA_SHADER_FRAGMENT
);
1485 unsigned max_output_components
=
1486 ctx
->Const
.Program
[producer
->Stage
].MaxOutputComponents
;
1488 const unsigned output_components
= output_vectors
* 4;
1489 if (output_components
> max_output_components
) {
1490 if (ctx
->API
== API_OPENGLES2
|| prog
->IsES
)
1491 linker_error(prog
, "shader uses too many output vectors "
1494 max_output_components
/ 4);
1496 linker_error(prog
, "shader uses too many output components "
1499 max_output_components
);
1508 check_against_input_limit(struct gl_context
*ctx
,
1509 struct gl_shader_program
*prog
,
1510 gl_shader
*consumer
)
1512 unsigned input_vectors
= 0;
1514 foreach_list(node
, consumer
->ir
) {
1515 ir_variable
*const var
= ((ir_instruction
*) node
)->as_variable();
1517 if (var
&& var
->data
.mode
== ir_var_shader_in
&&
1518 var_counts_against_varying_limit(consumer
->Stage
, var
)) {
1519 input_vectors
+= var
->type
->count_attribute_slots();
1523 assert(consumer
->Stage
!= MESA_SHADER_VERTEX
);
1524 unsigned max_input_components
=
1525 ctx
->Const
.Program
[consumer
->Stage
].MaxInputComponents
;
1527 const unsigned input_components
= input_vectors
* 4;
1528 if (input_components
> max_input_components
) {
1529 if (ctx
->API
== API_OPENGLES2
|| prog
->IsES
)
1530 linker_error(prog
, "shader uses too many input vectors "
1533 max_input_components
/ 4);
1535 linker_error(prog
, "shader uses too many input components "
1538 max_input_components
);