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5 * copy of this software and associated documentation files (the "Software"),
6 * to deal in the Software without restriction, including without limitation
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9 * Software is furnished to do so, subject to the following conditions:
11 * The above copyright notice and this permission notice (including the next
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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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19 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
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21 * DEALINGS IN THE SOFTWARE.
25 * \file lower_varyings_to_packed.cpp
27 * This lowering pass generates GLSL code that manually packs varyings into
28 * vec4 slots, for the benefit of back-ends that don't support packed varyings
31 * For example, the following shader:
33 * out mat3x2 foo; // location=4, location_frac=0
34 * out vec3 bar[2]; // location=5, location_frac=2
45 * out vec4 packed4; // location=4, location_frac=0
46 * out vec4 packed5; // location=5, location_frac=0
47 * out vec4 packed6; // location=6, location_frac=0
52 * packed4.xy = foo[0];
53 * packed4.zw = foo[1];
54 * packed5.xy = foo[2];
55 * packed5.zw = bar[0].xy;
56 * packed6.x = bar[0].z;
57 * packed6.yzw = bar[1];
60 * This lowering pass properly handles "double parking" of a varying vector
61 * across two varying slots. For example, in the code above, two of the
62 * components of bar[0] are stored in packed5, and the remaining component is
65 * Note that in theory, the extra instructions may cause some loss of
66 * performance. However, hopefully in most cases the performance loss will
67 * either be absorbed by a later optimization pass, or it will be offset by
68 * memory bandwidth savings (because fewer varyings are used).
70 * This lowering pass also packs flat floats, ints, and uints together, by
71 * using ivec4 as the base type of flat "varyings", and using appropriate
72 * casts to convert floats and uints into ints.
74 * This lowering pass also handles varyings whose type is a struct or an array
75 * of struct. Structs are packed in order and with no gaps, so there may be a
76 * performance penalty due to structure elements being double-parked.
78 * Lowering of geometry shader inputs is slightly more complex, since geometry
79 * inputs are always arrays, so we need to lower arrays to arrays. For
80 * example, the following input:
86 * } arr[3]; // location=4, location_frac=0
88 * Would get lowered like this if it occurred in a fragment shader:
95 * in vec4 packed4; // location=4, location_frac=0
96 * in vec4 packed5; // location=5, location_frac=0
97 * in vec4 packed6; // location=6, location_frac=0
98 * in vec4 packed7; // location=7, location_frac=0
99 * in vec4 packed8; // location=8, location_frac=0
100 * in vec4 packed9; // location=9, location_frac=0
104 * arr[0].f = packed4.x;
105 * arr[0].v = packed4.yzw;
106 * arr[0].a[0] = packed5.xy;
107 * arr[0].a[1] = packed5.zw;
108 * arr[1].f = packed6.x;
109 * arr[1].v = packed6.yzw;
110 * arr[1].a[0] = packed7.xy;
111 * arr[1].a[1] = packed7.zw;
112 * arr[2].f = packed8.x;
113 * arr[2].v = packed8.yzw;
114 * arr[2].a[0] = packed9.xy;
115 * arr[2].a[1] = packed9.zw;
119 * But it would get lowered like this if it occurred in a geometry shader:
126 * in vec4 packed4[3]; // location=4, location_frac=0
127 * in vec4 packed5[3]; // location=5, location_frac=0
131 * arr[0].f = packed4[0].x;
132 * arr[0].v = packed4[0].yzw;
133 * arr[0].a[0] = packed5[0].xy;
134 * arr[0].a[1] = packed5[0].zw;
135 * arr[1].f = packed4[1].x;
136 * arr[1].v = packed4[1].yzw;
137 * arr[1].a[0] = packed5[1].xy;
138 * arr[1].a[1] = packed5[1].zw;
139 * arr[2].f = packed4[2].x;
140 * arr[2].v = packed4[2].yzw;
141 * arr[2].a[0] = packed5[2].xy;
142 * arr[2].a[1] = packed5[2].zw;
147 #include "glsl_symbol_table.h"
149 #include "ir_builder.h"
150 #include "ir_optimization.h"
151 #include "program/prog_instruction.h"
152 #include "main/mtypes.h"
154 using namespace ir_builder
;
159 * Visitor that performs varying packing. For each varying declared in the
160 * shader, this visitor determines whether it needs to be packed. If so, it
161 * demotes it to an ordinary global, creates new packed varyings, and
162 * generates assignments to convert between the original varying and the
165 class lower_packed_varyings_visitor
168 lower_packed_varyings_visitor(void *mem_ctx
,
169 unsigned locations_used
,
170 const uint8_t *components
,
171 ir_variable_mode mode
,
172 unsigned gs_input_vertices
,
173 exec_list
*out_instructions
,
174 exec_list
*out_variables
,
175 bool disable_varying_packing
,
178 void run(struct gl_linked_shader
*shader
);
181 void bitwise_assign_pack(ir_rvalue
*lhs
, ir_rvalue
*rhs
);
182 void bitwise_assign_unpack(ir_rvalue
*lhs
, ir_rvalue
*rhs
);
183 unsigned lower_rvalue(ir_rvalue
*rvalue
, unsigned fine_location
,
184 ir_variable
*unpacked_var
, const char *name
,
185 bool gs_input_toplevel
, unsigned vertex_index
);
186 unsigned lower_arraylike(ir_rvalue
*rvalue
, unsigned array_size
,
187 unsigned fine_location
,
188 ir_variable
*unpacked_var
, const char *name
,
189 bool gs_input_toplevel
, unsigned vertex_index
);
190 ir_dereference
*get_packed_varying_deref(unsigned location
,
191 ir_variable
*unpacked_var
,
193 unsigned vertex_index
);
194 bool needs_lowering(ir_variable
*var
);
197 * Memory context used to allocate new instructions for the shader.
199 void * const mem_ctx
;
202 * Number of generic varying slots which are used by this shader. This is
203 * used to allocate temporary intermediate data structures. If any varying
204 * used by this shader has a location greater than or equal to
205 * VARYING_SLOT_VAR0 + locations_used, an assertion will fire.
207 const unsigned locations_used
;
209 const uint8_t* components
;
212 * Array of pointers to the packed varyings that have been created for each
213 * generic varying slot. NULL entries in this array indicate varying slots
214 * for which a packed varying has not been created yet.
216 ir_variable
**packed_varyings
;
219 * Type of varying which is being lowered in this pass (either
220 * ir_var_shader_in or ir_var_shader_out).
222 const ir_variable_mode mode
;
225 * If we are currently lowering geometry shader inputs, the number of input
226 * vertices the geometry shader accepts. Otherwise zero.
228 const unsigned gs_input_vertices
;
231 * Exec list into which the visitor should insert the packing instructions.
232 * Caller provides this list; it should insert the instructions into the
233 * appropriate place in the shader once the visitor has finished running.
235 exec_list
*out_instructions
;
238 * Exec list into which the visitor should insert any new variables.
240 exec_list
*out_variables
;
242 bool disable_varying_packing
;
246 } /* anonymous namespace */
248 lower_packed_varyings_visitor::lower_packed_varyings_visitor(
249 void *mem_ctx
, unsigned locations_used
, const uint8_t *components
,
250 ir_variable_mode mode
,
251 unsigned gs_input_vertices
, exec_list
*out_instructions
,
252 exec_list
*out_variables
, bool disable_varying_packing
,
255 locations_used(locations_used
),
256 components(components
),
257 packed_varyings((ir_variable
**)
258 rzalloc_array_size(mem_ctx
, sizeof(*packed_varyings
),
261 gs_input_vertices(gs_input_vertices
),
262 out_instructions(out_instructions
),
263 out_variables(out_variables
),
264 disable_varying_packing(disable_varying_packing
),
265 xfb_enabled(xfb_enabled
)
270 lower_packed_varyings_visitor::run(struct gl_linked_shader
*shader
)
272 foreach_in_list(ir_instruction
, node
, shader
->ir
) {
273 ir_variable
*var
= node
->as_variable();
277 if (var
->data
.mode
!= this->mode
||
278 var
->data
.location
< VARYING_SLOT_VAR0
||
279 !this->needs_lowering(var
))
282 /* This lowering pass is only capable of packing floats and ints
283 * together when their interpolation mode is "flat". Treat integers as
284 * being flat when the interpolation mode is none.
286 assert(var
->data
.interpolation
== INTERP_MODE_FLAT
||
287 var
->data
.interpolation
== INTERP_MODE_NONE
||
288 !var
->type
->contains_integer());
290 /* Clone the variable for program resource list before
291 * it gets modified and lost.
293 if (!shader
->packed_varyings
)
294 shader
->packed_varyings
= new (shader
) exec_list
;
296 shader
->packed_varyings
->push_tail(var
->clone(shader
, NULL
));
298 /* Change the old varying into an ordinary global. */
299 assert(var
->data
.mode
!= ir_var_temporary
);
300 var
->data
.mode
= ir_var_auto
;
302 /* Create a reference to the old varying. */
303 ir_dereference_variable
*deref
304 = new(this->mem_ctx
) ir_dereference_variable(var
);
306 /* Recursively pack or unpack it. */
307 this->lower_rvalue(deref
, var
->data
.location
* 4 + var
->data
.location_frac
, var
,
308 var
->name
, this->gs_input_vertices
!= 0, 0);
312 #define SWIZZLE_ZWZW MAKE_SWIZZLE4(SWIZZLE_Z, SWIZZLE_W, SWIZZLE_Z, SWIZZLE_W)
315 * Make an ir_assignment from \c rhs to \c lhs, performing appropriate
316 * bitcasts if necessary to match up types.
318 * This function is called when packing varyings.
321 lower_packed_varyings_visitor::bitwise_assign_pack(ir_rvalue
*lhs
,
324 if (lhs
->type
->base_type
!= rhs
->type
->base_type
) {
325 /* Since we only mix types in flat varyings, and we always store flat
326 * varyings as type ivec4, we need only produce conversions from (uint
329 assert(lhs
->type
->base_type
== GLSL_TYPE_INT
);
330 switch (rhs
->type
->base_type
) {
332 rhs
= new(this->mem_ctx
)
333 ir_expression(ir_unop_u2i
, lhs
->type
, rhs
);
335 case GLSL_TYPE_FLOAT
:
336 rhs
= new(this->mem_ctx
)
337 ir_expression(ir_unop_bitcast_f2i
, lhs
->type
, rhs
);
339 case GLSL_TYPE_DOUBLE
:
340 assert(rhs
->type
->vector_elements
<= 2);
341 if (rhs
->type
->vector_elements
== 2) {
342 ir_variable
*t
= new(mem_ctx
) ir_variable(lhs
->type
, "pack", ir_var_temporary
);
344 assert(lhs
->type
->vector_elements
== 4);
345 this->out_variables
->push_tail(t
);
346 this->out_instructions
->push_tail(
347 assign(t
, u2i(expr(ir_unop_unpack_double_2x32
, swizzle_x(rhs
->clone(mem_ctx
, NULL
)))), 0x3));
348 this->out_instructions
->push_tail(
349 assign(t
, u2i(expr(ir_unop_unpack_double_2x32
, swizzle_y(rhs
))), 0xc));
352 rhs
= u2i(expr(ir_unop_unpack_double_2x32
, rhs
));
355 case GLSL_TYPE_INT64
:
356 assert(rhs
->type
->vector_elements
<= 2);
357 if (rhs
->type
->vector_elements
== 2) {
358 ir_variable
*t
= new(mem_ctx
) ir_variable(lhs
->type
, "pack", ir_var_temporary
);
360 assert(lhs
->type
->vector_elements
== 4);
361 this->out_variables
->push_tail(t
);
362 this->out_instructions
->push_tail(
363 assign(t
, expr(ir_unop_unpack_int_2x32
, swizzle_x(rhs
->clone(mem_ctx
, NULL
))), 0x3));
364 this->out_instructions
->push_tail(
365 assign(t
, expr(ir_unop_unpack_int_2x32
, swizzle_y(rhs
)), 0xc));
368 rhs
= expr(ir_unop_unpack_int_2x32
, rhs
);
371 case GLSL_TYPE_UINT64
:
372 assert(rhs
->type
->vector_elements
<= 2);
373 if (rhs
->type
->vector_elements
== 2) {
374 ir_variable
*t
= new(mem_ctx
) ir_variable(lhs
->type
, "pack", ir_var_temporary
);
376 assert(lhs
->type
->vector_elements
== 4);
377 this->out_variables
->push_tail(t
);
378 this->out_instructions
->push_tail(
379 assign(t
, u2i(expr(ir_unop_unpack_uint_2x32
, swizzle_x(rhs
->clone(mem_ctx
, NULL
)))), 0x3));
380 this->out_instructions
->push_tail(
381 assign(t
, u2i(expr(ir_unop_unpack_uint_2x32
, swizzle_y(rhs
))), 0xc));
384 rhs
= u2i(expr(ir_unop_unpack_uint_2x32
, rhs
));
387 case GLSL_TYPE_SAMPLER
:
388 rhs
= u2i(expr(ir_unop_unpack_sampler_2x32
, rhs
));
390 case GLSL_TYPE_IMAGE
:
391 rhs
= u2i(expr(ir_unop_unpack_image_2x32
, rhs
));
394 assert(!"Unexpected type conversion while lowering varyings");
398 this->out_instructions
->push_tail(new (this->mem_ctx
) ir_assignment(lhs
, rhs
));
403 * Make an ir_assignment from \c rhs to \c lhs, performing appropriate
404 * bitcasts if necessary to match up types.
406 * This function is called when unpacking varyings.
409 lower_packed_varyings_visitor::bitwise_assign_unpack(ir_rvalue
*lhs
,
412 if (lhs
->type
->base_type
!= rhs
->type
->base_type
) {
413 /* Since we only mix types in flat varyings, and we always store flat
414 * varyings as type ivec4, we need only produce conversions from int to
417 assert(rhs
->type
->base_type
== GLSL_TYPE_INT
);
418 switch (lhs
->type
->base_type
) {
420 rhs
= new(this->mem_ctx
)
421 ir_expression(ir_unop_i2u
, lhs
->type
, rhs
);
423 case GLSL_TYPE_FLOAT
:
424 rhs
= new(this->mem_ctx
)
425 ir_expression(ir_unop_bitcast_i2f
, lhs
->type
, rhs
);
427 case GLSL_TYPE_DOUBLE
:
428 assert(lhs
->type
->vector_elements
<= 2);
429 if (lhs
->type
->vector_elements
== 2) {
430 ir_variable
*t
= new(mem_ctx
) ir_variable(lhs
->type
, "unpack", ir_var_temporary
);
431 assert(rhs
->type
->vector_elements
== 4);
432 this->out_variables
->push_tail(t
);
433 this->out_instructions
->push_tail(
434 assign(t
, expr(ir_unop_pack_double_2x32
, i2u(swizzle_xy(rhs
->clone(mem_ctx
, NULL
)))), 0x1));
435 this->out_instructions
->push_tail(
436 assign(t
, expr(ir_unop_pack_double_2x32
, i2u(swizzle(rhs
->clone(mem_ctx
, NULL
), SWIZZLE_ZWZW
, 2))), 0x2));
439 rhs
= expr(ir_unop_pack_double_2x32
, i2u(rhs
));
442 case GLSL_TYPE_INT64
:
443 assert(lhs
->type
->vector_elements
<= 2);
444 if (lhs
->type
->vector_elements
== 2) {
445 ir_variable
*t
= new(mem_ctx
) ir_variable(lhs
->type
, "unpack", ir_var_temporary
);
446 assert(rhs
->type
->vector_elements
== 4);
447 this->out_variables
->push_tail(t
);
448 this->out_instructions
->push_tail(
449 assign(t
, expr(ir_unop_pack_int_2x32
, swizzle_xy(rhs
->clone(mem_ctx
, NULL
))), 0x1));
450 this->out_instructions
->push_tail(
451 assign(t
, expr(ir_unop_pack_int_2x32
, swizzle(rhs
->clone(mem_ctx
, NULL
), SWIZZLE_ZWZW
, 2)), 0x2));
454 rhs
= expr(ir_unop_pack_int_2x32
, rhs
);
457 case GLSL_TYPE_UINT64
:
458 assert(lhs
->type
->vector_elements
<= 2);
459 if (lhs
->type
->vector_elements
== 2) {
460 ir_variable
*t
= new(mem_ctx
) ir_variable(lhs
->type
, "unpack", ir_var_temporary
);
461 assert(rhs
->type
->vector_elements
== 4);
462 this->out_variables
->push_tail(t
);
463 this->out_instructions
->push_tail(
464 assign(t
, expr(ir_unop_pack_uint_2x32
, i2u(swizzle_xy(rhs
->clone(mem_ctx
, NULL
)))), 0x1));
465 this->out_instructions
->push_tail(
466 assign(t
, expr(ir_unop_pack_uint_2x32
, i2u(swizzle(rhs
->clone(mem_ctx
, NULL
), SWIZZLE_ZWZW
, 2))), 0x2));
469 rhs
= expr(ir_unop_pack_uint_2x32
, i2u(rhs
));
472 case GLSL_TYPE_SAMPLER
:
474 ir_expression(ir_unop_pack_sampler_2x32
, lhs
->type
, i2u(rhs
));
476 case GLSL_TYPE_IMAGE
:
478 ir_expression(ir_unop_pack_image_2x32
, lhs
->type
, i2u(rhs
));
481 assert(!"Unexpected type conversion while lowering varyings");
485 this->out_instructions
->push_tail(new(this->mem_ctx
) ir_assignment(lhs
, rhs
));
490 * Recursively pack or unpack the given varying (or portion of a varying) by
491 * traversing all of its constituent vectors.
493 * \param fine_location is the location where the first constituent vector
494 * should be packed--the word "fine" indicates that this location is expressed
495 * in multiples of a float, rather than multiples of a vec4 as is used
498 * \param gs_input_toplevel should be set to true if we are lowering geometry
499 * shader inputs, and we are currently lowering the whole input variable
500 * (i.e. we are lowering the array whose index selects the vertex).
502 * \param vertex_index: if we are lowering geometry shader inputs, and the
503 * level of the array that we are currently lowering is *not* the top level,
504 * then this indicates which vertex we are currently lowering. Otherwise it
507 * \return the location where the next constituent vector (after this one)
511 lower_packed_varyings_visitor::lower_rvalue(ir_rvalue
*rvalue
,
512 unsigned fine_location
,
513 ir_variable
*unpacked_var
,
515 bool gs_input_toplevel
,
516 unsigned vertex_index
)
518 unsigned dmul
= rvalue
->type
->is_64bit() ? 2 : 1;
519 /* When gs_input_toplevel is set, we should be looking at a geometry shader
522 assert(!gs_input_toplevel
|| rvalue
->type
->is_array());
524 if (rvalue
->type
->is_struct()) {
525 for (unsigned i
= 0; i
< rvalue
->type
->length
; i
++) {
527 rvalue
= rvalue
->clone(this->mem_ctx
, NULL
);
528 const char *field_name
= rvalue
->type
->fields
.structure
[i
].name
;
529 ir_dereference_record
*dereference_record
= new(this->mem_ctx
)
530 ir_dereference_record(rvalue
, field_name
);
532 = ralloc_asprintf(this->mem_ctx
, "%s.%s", name
, field_name
);
533 fine_location
= this->lower_rvalue(dereference_record
, fine_location
,
534 unpacked_var
, deref_name
, false,
537 return fine_location
;
538 } else if (rvalue
->type
->is_array()) {
539 /* Arrays are packed/unpacked by considering each array element in
542 return this->lower_arraylike(rvalue
, rvalue
->type
->array_size(),
543 fine_location
, unpacked_var
, name
,
544 gs_input_toplevel
, vertex_index
);
545 } else if (rvalue
->type
->is_matrix()) {
546 /* Matrices are packed/unpacked by considering each column vector in
549 return this->lower_arraylike(rvalue
, rvalue
->type
->matrix_columns
,
550 fine_location
, unpacked_var
, name
,
551 false, vertex_index
);
552 } else if (rvalue
->type
->vector_elements
* dmul
+
553 fine_location
% 4 > 4) {
554 /* This vector is going to be "double parked" across two varying slots,
555 * so handle it as two separate assignments. For doubles, a dvec3/dvec4
556 * can end up being spread over 3 slots. However the second splitting
557 * will happen later, here we just always want to split into 2.
559 unsigned left_components
, right_components
;
560 unsigned left_swizzle_values
[4] = { 0, 0, 0, 0 };
561 unsigned right_swizzle_values
[4] = { 0, 0, 0, 0 };
562 char left_swizzle_name
[4] = { 0, 0, 0, 0 };
563 char right_swizzle_name
[4] = { 0, 0, 0, 0 };
565 left_components
= 4 - fine_location
% 4;
566 if (rvalue
->type
->is_64bit()) {
567 /* We might actually end up with 0 left components! */
568 left_components
/= 2;
570 right_components
= rvalue
->type
->vector_elements
- left_components
;
572 for (unsigned i
= 0; i
< left_components
; i
++) {
573 left_swizzle_values
[i
] = i
;
574 left_swizzle_name
[i
] = "xyzw"[i
];
576 for (unsigned i
= 0; i
< right_components
; i
++) {
577 right_swizzle_values
[i
] = i
+ left_components
;
578 right_swizzle_name
[i
] = "xyzw"[i
+ left_components
];
580 ir_swizzle
*left_swizzle
= new(this->mem_ctx
)
581 ir_swizzle(rvalue
, left_swizzle_values
, left_components
);
582 ir_swizzle
*right_swizzle
= new(this->mem_ctx
)
583 ir_swizzle(rvalue
->clone(this->mem_ctx
, NULL
), right_swizzle_values
,
586 = ralloc_asprintf(this->mem_ctx
, "%s.%s", name
, left_swizzle_name
);
588 = ralloc_asprintf(this->mem_ctx
, "%s.%s", name
, right_swizzle_name
);
590 fine_location
= this->lower_rvalue(left_swizzle
, fine_location
,
591 unpacked_var
, left_name
, false,
594 /* Top up the fine location to the next slot */
596 return this->lower_rvalue(right_swizzle
, fine_location
, unpacked_var
,
597 right_name
, false, vertex_index
);
599 /* No special handling is necessary; pack the rvalue into the
602 unsigned swizzle_values
[4] = { 0, 0, 0, 0 };
603 unsigned components
= rvalue
->type
->vector_elements
* dmul
;
604 unsigned location
= fine_location
/ 4;
605 unsigned location_frac
= fine_location
% 4;
606 for (unsigned i
= 0; i
< components
; ++i
)
607 swizzle_values
[i
] = i
+ location_frac
;
608 ir_dereference
*packed_deref
=
609 this->get_packed_varying_deref(location
, unpacked_var
, name
,
611 if (unpacked_var
->data
.stream
!= 0) {
612 assert(unpacked_var
->data
.stream
< 4);
613 ir_variable
*packed_var
= packed_deref
->variable_referenced();
614 for (unsigned i
= 0; i
< components
; ++i
) {
615 packed_var
->data
.stream
|=
616 unpacked_var
->data
.stream
<< (2 * (location_frac
+ i
));
619 ir_swizzle
*swizzle
= new(this->mem_ctx
)
620 ir_swizzle(packed_deref
, swizzle_values
, components
);
621 if (this->mode
== ir_var_shader_out
) {
622 this->bitwise_assign_pack(swizzle
, rvalue
);
624 this->bitwise_assign_unpack(rvalue
, swizzle
);
626 return fine_location
+ components
;
631 * Recursively pack or unpack a varying for which we need to iterate over its
632 * constituent elements, accessing each one using an ir_dereference_array.
633 * This takes care of both arrays and matrices, since ir_dereference_array
634 * treats a matrix like an array of its column vectors.
636 * \param gs_input_toplevel should be set to true if we are lowering geometry
637 * shader inputs, and we are currently lowering the whole input variable
638 * (i.e. we are lowering the array whose index selects the vertex).
640 * \param vertex_index: if we are lowering geometry shader inputs, and the
641 * level of the array that we are currently lowering is *not* the top level,
642 * then this indicates which vertex we are currently lowering. Otherwise it
646 lower_packed_varyings_visitor::lower_arraylike(ir_rvalue
*rvalue
,
648 unsigned fine_location
,
649 ir_variable
*unpacked_var
,
651 bool gs_input_toplevel
,
652 unsigned vertex_index
)
654 for (unsigned i
= 0; i
< array_size
; i
++) {
656 rvalue
= rvalue
->clone(this->mem_ctx
, NULL
);
657 ir_constant
*constant
= new(this->mem_ctx
) ir_constant(i
);
658 ir_dereference_array
*dereference_array
= new(this->mem_ctx
)
659 ir_dereference_array(rvalue
, constant
);
660 if (gs_input_toplevel
) {
661 /* Geometry shader inputs are a special case. Instead of storing
662 * each element of the array at a different location, all elements
663 * are at the same location, but with a different vertex index.
665 (void) this->lower_rvalue(dereference_array
, fine_location
,
666 unpacked_var
, name
, false, i
);
668 char *subscripted_name
669 = ralloc_asprintf(this->mem_ctx
, "%s[%d]", name
, i
);
671 this->lower_rvalue(dereference_array
, fine_location
,
672 unpacked_var
, subscripted_name
,
673 false, vertex_index
);
676 return fine_location
;
680 * Retrieve the packed varying corresponding to the given varying location.
681 * If no packed varying has been created for the given varying location yet,
682 * create it and add it to the shader before returning it.
684 * The newly created varying inherits its interpolation parameters from \c
685 * unpacked_var. Its base type is ivec4 if we are lowering a flat varying,
688 * \param vertex_index: if we are lowering geometry shader inputs, then this
689 * indicates which vertex we are currently lowering. Otherwise it is ignored.
692 lower_packed_varyings_visitor::get_packed_varying_deref(
693 unsigned location
, ir_variable
*unpacked_var
, const char *name
,
694 unsigned vertex_index
)
696 unsigned slot
= location
- VARYING_SLOT_VAR0
;
697 assert(slot
< locations_used
);
698 if (this->packed_varyings
[slot
] == NULL
) {
699 char *packed_name
= ralloc_asprintf(this->mem_ctx
, "packed:%s", name
);
700 const glsl_type
*packed_type
;
701 assert(components
[slot
] != 0);
702 if (unpacked_var
->is_interpolation_flat())
703 packed_type
= glsl_type::get_instance(GLSL_TYPE_INT
, components
[slot
], 1);
705 packed_type
= glsl_type::get_instance(GLSL_TYPE_FLOAT
, components
[slot
], 1);
706 if (this->gs_input_vertices
!= 0) {
708 glsl_type::get_array_instance(packed_type
,
709 this->gs_input_vertices
);
711 ir_variable
*packed_var
= new(this->mem_ctx
)
712 ir_variable(packed_type
, packed_name
, this->mode
);
713 if (this->gs_input_vertices
!= 0) {
714 /* Prevent update_array_sizes() from messing with the size of the
717 packed_var
->data
.max_array_access
= this->gs_input_vertices
- 1;
719 packed_var
->data
.centroid
= unpacked_var
->data
.centroid
;
720 packed_var
->data
.sample
= unpacked_var
->data
.sample
;
721 packed_var
->data
.patch
= unpacked_var
->data
.patch
;
722 packed_var
->data
.interpolation
=
723 packed_type
->without_array() == glsl_type::ivec4_type
724 ? unsigned(INTERP_MODE_FLAT
) : unpacked_var
->data
.interpolation
;
725 packed_var
->data
.location
= location
;
726 packed_var
->data
.precision
= unpacked_var
->data
.precision
;
727 packed_var
->data
.always_active_io
= unpacked_var
->data
.always_active_io
;
728 packed_var
->data
.stream
= 1u << 31;
729 unpacked_var
->insert_before(packed_var
);
730 this->packed_varyings
[slot
] = packed_var
;
732 ir_variable
*var
= this->packed_varyings
[slot
];
734 /* The slot needs to be marked as always active if any variable that got
737 var
->data
.always_active_io
|= unpacked_var
->data
.always_active_io
;
739 /* For geometry shader inputs, only update the packed variable name the
740 * first time we visit each component.
742 if (this->gs_input_vertices
== 0 || vertex_index
== 0) {
743 if (var
->is_name_ralloced())
744 ralloc_asprintf_append((char **) &var
->name
, ",%s", name
);
746 var
->name
= ralloc_asprintf(var
, "%s,%s", var
->name
, name
);
750 ir_dereference
*deref
= new(this->mem_ctx
)
751 ir_dereference_variable(this->packed_varyings
[slot
]);
752 if (this->gs_input_vertices
!= 0) {
753 /* When lowering GS inputs, the packed variable is an array, so we need
754 * to dereference it using vertex_index.
756 ir_constant
*constant
= new(this->mem_ctx
) ir_constant(vertex_index
);
757 deref
= new(this->mem_ctx
) ir_dereference_array(deref
, constant
);
763 lower_packed_varyings_visitor::needs_lowering(ir_variable
*var
)
765 /* Things composed of vec4's, varyings with explicitly assigned
766 * locations or varyings marked as must_be_shader_input (which might be used
767 * by interpolateAt* functions) shouldn't be lowered. Everything else can be.
769 if (var
->data
.explicit_location
|| var
->data
.must_be_shader_input
)
772 /* Override disable_varying_packing if the var is only used by transform
773 * feedback. Also override it if transform feedback is enabled and the
774 * variable is an array, struct or matrix as the elements of these types
775 * will always have the same interpolation and therefore are safe to pack.
777 const glsl_type
*type
= var
->type
;
778 if (disable_varying_packing
&& !var
->data
.is_xfb_only
&&
779 !((type
->is_array() || type
->is_struct() || type
->is_matrix()) &&
783 type
= type
->without_array();
784 if (type
->vector_elements
== 4 && !type
->is_64bit())
791 * Visitor that splices varying packing code before every use of EmitVertex()
792 * in a geometry shader.
794 class lower_packed_varyings_gs_splicer
: public ir_hierarchical_visitor
797 explicit lower_packed_varyings_gs_splicer(void *mem_ctx
,
798 const exec_list
*instructions
);
800 virtual ir_visitor_status
visit_leave(ir_emit_vertex
*ev
);
804 * Memory context used to allocate new instructions for the shader.
806 void * const mem_ctx
;
809 * Instructions that should be spliced into place before each EmitVertex()
812 const exec_list
*instructions
;
816 lower_packed_varyings_gs_splicer::lower_packed_varyings_gs_splicer(
817 void *mem_ctx
, const exec_list
*instructions
)
818 : mem_ctx(mem_ctx
), instructions(instructions
)
824 lower_packed_varyings_gs_splicer::visit_leave(ir_emit_vertex
*ev
)
826 foreach_in_list(ir_instruction
, ir
, this->instructions
) {
827 ev
->insert_before(ir
->clone(this->mem_ctx
, NULL
));
829 return visit_continue
;
833 * Visitor that splices varying packing code before every return.
835 class lower_packed_varyings_return_splicer
: public ir_hierarchical_visitor
838 explicit lower_packed_varyings_return_splicer(void *mem_ctx
,
839 const exec_list
*instructions
);
841 virtual ir_visitor_status
visit_leave(ir_return
*ret
);
845 * Memory context used to allocate new instructions for the shader.
847 void * const mem_ctx
;
850 * Instructions that should be spliced into place before each return.
852 const exec_list
*instructions
;
856 lower_packed_varyings_return_splicer::lower_packed_varyings_return_splicer(
857 void *mem_ctx
, const exec_list
*instructions
)
858 : mem_ctx(mem_ctx
), instructions(instructions
)
864 lower_packed_varyings_return_splicer::visit_leave(ir_return
*ret
)
866 foreach_in_list(ir_instruction
, ir
, this->instructions
) {
867 ret
->insert_before(ir
->clone(this->mem_ctx
, NULL
));
869 return visit_continue
;
873 lower_packed_varyings(void *mem_ctx
, unsigned locations_used
,
874 const uint8_t *components
,
875 ir_variable_mode mode
, unsigned gs_input_vertices
,
876 gl_linked_shader
*shader
, bool disable_varying_packing
,
879 exec_list
*instructions
= shader
->ir
;
880 ir_function
*main_func
= shader
->symbols
->get_function("main");
881 exec_list void_parameters
;
882 ir_function_signature
*main_func_sig
883 = main_func
->matching_signature(NULL
, &void_parameters
, false);
884 exec_list new_instructions
, new_variables
;
885 lower_packed_varyings_visitor
visitor(mem_ctx
,
892 disable_varying_packing
,
895 if (mode
== ir_var_shader_out
) {
896 if (shader
->Stage
== MESA_SHADER_GEOMETRY
) {
897 /* For geometry shaders, outputs need to be lowered before each call
900 lower_packed_varyings_gs_splicer
splicer(mem_ctx
, &new_instructions
);
902 /* Add all the variables in first. */
903 main_func_sig
->body
.get_head_raw()->insert_before(&new_variables
);
905 /* Now update all the EmitVertex instances */
906 splicer
.run(instructions
);
908 /* For other shader types, outputs need to be lowered before each
909 * return statement and at the end of main()
912 lower_packed_varyings_return_splicer
splicer(mem_ctx
, &new_instructions
);
914 main_func_sig
->body
.get_head_raw()->insert_before(&new_variables
);
916 splicer
.run(instructions
);
918 /* Lower outputs at the end of main() if the last instruction is not
921 if (((ir_instruction
*)instructions
->get_tail())->ir_type
!= ir_type_return
) {
922 main_func_sig
->body
.append_list(&new_instructions
);
926 /* Shader inputs need to be lowered at the beginning of main() */
927 main_func_sig
->body
.get_head_raw()->insert_before(&new_instructions
);
928 main_func_sig
->body
.get_head_raw()->insert_before(&new_variables
);