Google Git
Sign in
android / platform / external / mesa3d / ef961309bfa2c968710994b1bff87e6a13def150 / . / src / compiler / glsl / link_varyings.cpp
blob: 28187e2f0a43e53c2a4b09cf6ff9c8ccabf7d074 [file] [log] [blame]
/*
* Copyright © 2012 Intel Corporation
*
* Permission is hereby granted, free of charge, to any person obtaining a
* copy of this software and associated documentation files (the "Software"),
* to deal in the Software without restriction, including without limitation
* the rights to use, copy, modify, merge, publish, distribute, sublicense,
* and/or sell copies of the Software, and to permit persons to whom the
* Software is furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice (including the next
* paragraph) shall be included in all copies or substantial portions of the
* Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
* DEALINGS IN THE SOFTWARE.
*/
/**
* \file link_varyings.cpp
*
* Linker functions related specifically to linking varyings between shader
* stages.
*/
#include "main/errors.h"
#include "main/mtypes.h"
#include "glsl_symbol_table.h"
#include "glsl_parser_extras.h"
#include "ir_optimization.h"
#include "linker.h"
#include "link_varyings.h"
#include "main/macros.h"
#include "util/hash_table.h"
#include "util/u_math.h"
#include "program.h"
/**
* Get the varying type stripped of the outermost array if we're processing
* a stage whose varyings are arrays indexed by a vertex number (such as
* geometry shader inputs).
*/
static const glsl_type *
get_varying_type(const ir_variable *var, gl_shader_stage stage)
{
const glsl_type *type = var->type;
if (!var->data.patch &&
((var->data.mode == ir_var_shader_out &&
stage == MESA_SHADER_TESS_CTRL) ||
(var->data.mode == ir_var_shader_in &&
(stage == MESA_SHADER_TESS_CTRL || stage == MESA_SHADER_TESS_EVAL ||
stage == MESA_SHADER_GEOMETRY)))) {
assert(type->is_array());
type = type->fields.array;
}
return type;
}
static void
create_xfb_varying_names(void *mem_ctx, const glsl_type *t, char **name,
size_t name_length, unsigned *count,
const char *ifc_member_name,
const glsl_type *ifc_member_t, char ***varying_names)
{
if (t->is_interface()) {
size_t new_length = name_length;
assert(ifc_member_name && ifc_member_t);
ralloc_asprintf_rewrite_tail(name, &new_length, ".%s", ifc_member_name);
create_xfb_varying_names(mem_ctx, ifc_member_t, name, new_length, count,
NULL, NULL, varying_names);
} else if (t->is_record()) {
for (unsigned i = 0; i < t->length; i++) {
const char *field = t->fields.structure[i].name;
size_t new_length = name_length;
ralloc_asprintf_rewrite_tail(name, &new_length, ".%s", field);
create_xfb_varying_names(mem_ctx, t->fields.structure[i].type, name,
new_length, count, NULL, NULL,
varying_names);
}
} else if (t->without_array()->is_record() ||
t->without_array()->is_interface() ||
(t->is_array() && t->fields.array->is_array())) {
for (unsigned i = 0; i < t->length; i++) {
size_t new_length = name_length;
/* Append the subscript to the current variable name */
ralloc_asprintf_rewrite_tail(name, &new_length, "[%u]", i);
create_xfb_varying_names(mem_ctx, t->fields.array, name, new_length,
count, ifc_member_name, ifc_member_t,
varying_names);
}
} else {
(*varying_names)[(*count)++] = ralloc_strdup(mem_ctx, *name);
}
}
static bool
process_xfb_layout_qualifiers(void *mem_ctx, const gl_linked_shader *sh,
struct gl_shader_program *prog,
unsigned *num_tfeedback_decls,
char ***varying_names)
{
bool has_xfb_qualifiers = false;
/* We still need to enable transform feedback mode even if xfb_stride is
* only applied to a global out. Also we don't bother to propagate
* xfb_stride to interface block members so this will catch that case also.
*/
for (unsigned j = 0; j < MAX_FEEDBACK_BUFFERS; j++) {
if (prog->TransformFeedback.BufferStride[j]) {
has_xfb_qualifiers = true;
break;
}
}
foreach_in_list(ir_instruction, node, sh->ir) {
ir_variable *var = node->as_variable();
if (!var || var->data.mode != ir_var_shader_out)
continue;
/* From the ARB_enhanced_layouts spec:
*
* "Any shader making any static use (after preprocessing) of any of
* these *xfb_* qualifiers will cause the shader to be in a
* transform feedback capturing mode and hence responsible for
* describing the transform feedback setup. This mode will capture
* any output selected by *xfb_offset*, directly or indirectly, to
* a transform feedback buffer."
*/
if (var->data.explicit_xfb_buffer || var->data.explicit_xfb_stride) {
has_xfb_qualifiers = true;
}
if (var->data.explicit_xfb_offset) {
*num_tfeedback_decls += var->type->varying_count();
has_xfb_qualifiers = true;
}
}
if (*num_tfeedback_decls == 0)
return has_xfb_qualifiers;
unsigned i = 0;
*varying_names = ralloc_array(mem_ctx, char *, *num_tfeedback_decls);
foreach_in_list(ir_instruction, node, sh->ir) {
ir_variable *var = node->as_variable();
if (!var || var->data.mode != ir_var_shader_out)
continue;
if (var->data.explicit_xfb_offset) {
char *name;
const glsl_type *type, *member_type;
if (var->data.from_named_ifc_block) {
type = var->get_interface_type();
/* Find the member type before it was altered by lowering */
const glsl_type *type_wa = type->without_array();
member_type =
type_wa->fields.structure[type_wa->field_index(var->name)].type;
name = ralloc_strdup(NULL, type_wa->name);
} else {
type = var->type;
member_type = NULL;
name = ralloc_strdup(NULL, var->name);
}
create_xfb_varying_names(mem_ctx, type, &name, strlen(name), &i,
var->name, member_type, varying_names);
ralloc_free(name);
}
}
assert(i == *num_tfeedback_decls);
return has_xfb_qualifiers;
}
/**
* Validate the types and qualifiers of an output from one stage against the
* matching input to another stage.
*/
static void
cross_validate_types_and_qualifiers(struct gl_context *ctx,
struct gl_shader_program *prog,
const ir_variable *input,
const ir_variable *output,
gl_shader_stage consumer_stage,
gl_shader_stage producer_stage)
{
/* Check that the types match between stages.
*/
const glsl_type *type_to_match = input->type;
/* VS -> GS, VS -> TCS, VS -> TES, TES -> GS */
const bool extra_array_level = (producer_stage == MESA_SHADER_VERTEX &&
consumer_stage != MESA_SHADER_FRAGMENT) ||
consumer_stage == MESA_SHADER_GEOMETRY;
if (extra_array_level) {
assert(type_to_match->is_array());
type_to_match = type_to_match->fields.array;
}
if (type_to_match != output->type) {
/* There is a bit of a special case for gl_TexCoord. This
* built-in is unsized by default. Applications that variable
* access it must redeclare it with a size. There is some
* language in the GLSL spec that implies the fragment shader
* and vertex shader do not have to agree on this size. Other
* driver behave this way, and one or two applications seem to
* rely on it.
*
* Neither declaration needs to be modified here because the array
* sizes are fixed later when update_array_sizes is called.
*
* From page 48 (page 54 of the PDF) of the GLSL 1.10 spec:
*
* "Unlike user-defined varying variables, the built-in
* varying variables don't have a strict one-to-one
* correspondence between the vertex language and the
* fragment language."
*/
if (!output->type->is_array() || !is_gl_identifier(output->name)) {
linker_error(prog,
"%s shader output `%s' declared as type `%s', "
"but %s shader input declared as type `%s'\n",
_mesa_shader_stage_to_string(producer_stage),
output->name,
output->type->name,
_mesa_shader_stage_to_string(consumer_stage),
input->type->name);
return;
}
}
/* Check that all of the qualifiers match between stages.
*/
/* According to the OpenGL and OpenGLES GLSL specs, the centroid qualifier
* should match until OpenGL 4.3 and OpenGLES 3.1. The OpenGLES 3.0
* conformance test suite does not verify that the qualifiers must match.
* The deqp test suite expects the opposite (OpenGLES 3.1) behavior for
* OpenGLES 3.0 drivers, so we relax the checking in all cases.
*/
if (false /* always skip the centroid check */ &&
prog->data->Version < (prog->IsES ? 310 : 430) &&
input->data.centroid != output->data.centroid) {
linker_error(prog,
"%s shader output `%s' %s centroid qualifier, "
"but %s shader input %s centroid qualifier\n",
_mesa_shader_stage_to_string(producer_stage),
output->name,
(output->data.centroid) ? "has" : "lacks",
_mesa_shader_stage_to_string(consumer_stage),
(input->data.centroid) ? "has" : "lacks");
return;
}
if (input->data.sample != output->data.sample) {
linker_error(prog,
"%s shader output `%s' %s sample qualifier, "
"but %s shader input %s sample qualifier\n",
_mesa_shader_stage_to_string(producer_stage),
output->name,
(output->data.sample) ? "has" : "lacks",
_mesa_shader_stage_to_string(consumer_stage),
(input->data.sample) ? "has" : "lacks");
return;
}
if (input->data.patch != output->data.patch) {
linker_error(prog,
"%s shader output `%s' %s patch qualifier, "
"but %s shader input %s patch qualifier\n",
_mesa_shader_stage_to_string(producer_stage),
output->name,
(output->data.patch) ? "has" : "lacks",
_mesa_shader_stage_to_string(consumer_stage),
(input->data.patch) ? "has" : "lacks");
return;
}
/* The GLSL 4.30 and GLSL ES 3.00 specifications say:
*
* "As only outputs need be declared with invariant, an output from
* one shader stage will still match an input of a subsequent stage
* without the input being declared as invariant."
*
* while GLSL 4.20 says:
*
* "For variables leaving one shader and coming into another shader,
* the invariant keyword has to be used in both shaders, or a link
* error will result."
*
* and GLSL ES 1.00 section 4.6.4 "Invariance and Linking" says:
*
* "The invariance of varyings that are declared in both the vertex
* and fragment shaders must match."
*/
if (input->data.explicit_invariant != output->data.explicit_invariant &&
prog->data->Version < (prog->IsES ? 300 : 430)) {
linker_error(prog,
"%s shader output `%s' %s invariant qualifier, "
"but %s shader input %s invariant qualifier\n",
_mesa_shader_stage_to_string(producer_stage),
output->name,
(output->data.explicit_invariant) ? "has" : "lacks",
_mesa_shader_stage_to_string(consumer_stage),
(input->data.explicit_invariant) ? "has" : "lacks");
return;
}
/* GLSL >= 4.40 removes text requiring interpolation qualifiers
* to match cross stage, they must only match within the same stage.
*
* From page 84 (page 90 of the PDF) of the GLSL 4.40 spec:
*
* "It is a link-time error if, within the same stage, the interpolation
* qualifiers of variables of the same name do not match.
*
* Section 4.3.9 (Interpolation) of the GLSL ES 3.00 spec says:
*
* "When no interpolation qualifier is present, smooth interpolation
* is used."
*
* So we match variables where one is smooth and the other has no explicit
* qualifier.
*/
unsigned input_interpolation = input->data.interpolation;
unsigned output_interpolation = output->data.interpolation;
if (prog->IsES) {
if (input_interpolation == INTERP_MODE_NONE)
input_interpolation = INTERP_MODE_SMOOTH;
if (output_interpolation == INTERP_MODE_NONE)
output_interpolation = INTERP_MODE_SMOOTH;
}
if (input_interpolation != output_interpolation &&
prog->data->Version < 440) {
if (!ctx->Const.AllowGLSLCrossStageInterpolationMismatch) {
linker_error(prog,
"%s shader output `%s' specifies %s "
"interpolation qualifier, "
"but %s shader input specifies %s "
"interpolation qualifier\n",
_mesa_shader_stage_to_string(producer_stage),
output->name,
interpolation_string(output->data.interpolation),
_mesa_shader_stage_to_string(consumer_stage),
interpolation_string(input->data.interpolation));
return;
} else {
linker_warning(prog,
"%s shader output `%s' specifies %s "
"interpolation qualifier, "
"but %s shader input specifies %s "
"interpolation qualifier\n",
_mesa_shader_stage_to_string(producer_stage),
output->name,
interpolation_string(output->data.interpolation),
_mesa_shader_stage_to_string(consumer_stage),
interpolation_string(input->data.interpolation));
}
}
}
/**
* Validate front and back color outputs against single color input
*/
static void
cross_validate_front_and_back_color(struct gl_context *ctx,
struct gl_shader_program *prog,
const ir_variable *input,
const ir_variable *front_color,
const ir_variable *back_color,
gl_shader_stage consumer_stage,
gl_shader_stage producer_stage)
{
if (front_color != NULL && front_color->data.assigned)
cross_validate_types_and_qualifiers(ctx, prog, input, front_color,
consumer_stage, producer_stage);
if (back_color != NULL && back_color->data.assigned)
cross_validate_types_and_qualifiers(ctx, prog, input, back_color,
consumer_stage, producer_stage);
}
static unsigned
compute_variable_location_slot(ir_variable *var, gl_shader_stage stage)
{
unsigned location_start = VARYING_SLOT_VAR0;
switch (stage) {
case MESA_SHADER_VERTEX:
if (var->data.mode == ir_var_shader_in)
location_start = VERT_ATTRIB_GENERIC0;
break;
case MESA_SHADER_TESS_CTRL:
case MESA_SHADER_TESS_EVAL:
if (var->data.patch)
location_start = VARYING_SLOT_PATCH0;
break;
case MESA_SHADER_FRAGMENT:
if (var->data.mode == ir_var_shader_out)
location_start = FRAG_RESULT_DATA0;
break;
default:
break;
}
return var->data.location - location_start;
}
struct explicit_location_info {
ir_variable *var;
bool base_type_is_integer;
unsigned base_type_bit_size;
unsigned interpolation;
bool centroid;
bool sample;
bool patch;
};
static bool
check_location_aliasing(struct explicit_location_info explicit_locations[][4],
ir_variable *var,
unsigned location,
unsigned component,
unsigned location_limit,
const glsl_type *type,
unsigned interpolation,
bool centroid,
bool sample,
bool patch,
gl_shader_program *prog,
gl_shader_stage stage)
{
unsigned last_comp;
unsigned base_type_bit_size;
const glsl_type *type_without_array = type->without_array();
const bool base_type_is_integer =
glsl_base_type_is_integer(type_without_array->base_type);
const bool is_struct = type_without_array->is_record();
if (is_struct) {
/* structs don't have a defined underlying base type so just treat all
* component slots as used and set the bit size to 0. If there is
* location aliasing, we'll fail anyway later.
*/
last_comp = 4;
base_type_bit_size = 0;
} else {
unsigned dmul = type_without_array->is_64bit() ? 2 : 1;
last_comp = component + type_without_array->vector_elements * dmul;
base_type_bit_size =
glsl_base_type_get_bit_size(type_without_array->base_type);
}
while (location < location_limit) {
unsigned comp = 0;
while (comp < 4) {
struct explicit_location_info *info =
&explicit_locations[location][comp];
if (info->var) {
if (info->var->type->without_array()->is_record() || is_struct) {
/* Structs cannot share location since they are incompatible
* with any other underlying numerical type.
*/
linker_error(prog,
"%s shader has multiple %sputs sharing the "
"same location that don't have the same "
"underlying numerical type. Struct variable '%s', "
"location %u\n",
_mesa_shader_stage_to_string(stage),
var->data.mode == ir_var_shader_in ? "in" : "out",
is_struct ? var->name : info->var->name,
location);
return false;
} else if (comp >= component && comp < last_comp) {
/* Component aliasing is not allowed */
linker_error(prog,
"%s shader has multiple %sputs explicitly "
"assigned to location %d and component %d\n",
_mesa_shader_stage_to_string(stage),
var->data.mode == ir_var_shader_in ? "in" : "out",
location, comp);
return false;
} else {
/* From the OpenGL 4.60.5 spec, section 4.4.1 Input Layout
* Qualifiers, Page 67, (Location aliasing):
*
* " Further, when location aliasing, the aliases sharing the
* location must have the same underlying numerical type
* and bit width (floating-point or integer, 32-bit versus
* 64-bit, etc.) and the same auxiliary storage and
* interpolation qualification."
*/
/* If the underlying numerical type isn't integer, implicitly
* it will be float or else we would have failed by now.
*/
if (info->base_type_is_integer != base_type_is_integer) {
linker_error(prog,
"%s shader has multiple %sputs sharing the "
"same location that don't have the same "
"underlying numerical type. Location %u "
"component %u.\n",
_mesa_shader_stage_to_string(stage),
var->data.mode == ir_var_shader_in ?
"in" : "out", location, comp);
return false;
}
if (info->base_type_bit_size != base_type_bit_size) {
linker_error(prog,
"%s shader has multiple %sputs sharing the "
"same location that don't have the same "
"underlying numerical bit size. Location %u "
"component %u.\n",
_mesa_shader_stage_to_string(stage),
var->data.mode == ir_var_shader_in ?
"in" : "out", location, comp);
return false;
}
if (info->interpolation != interpolation) {
linker_error(prog,
"%s shader has multiple %sputs sharing the "
"same location that don't have the same "
"interpolation qualification. Location %u "
"component %u.\n",
_mesa_shader_stage_to_string(stage),
var->data.mode == ir_var_shader_in ?
"in" : "out", location, comp);
return false;
}
if (info->centroid != centroid ||
info->sample != sample ||
info->patch != patch) {
linker_error(prog,
"%s shader has multiple %sputs sharing the "
"same location that don't have the same "
"auxiliary storage qualification. Location %u "
"component %u.\n",
_mesa_shader_stage_to_string(stage),
var->data.mode == ir_var_shader_in ?
"in" : "out", location, comp);
return false;
}
}
} else if (comp >= component && comp < last_comp) {
info->var = var;
info->base_type_is_integer = base_type_is_integer;
info->base_type_bit_size = base_type_bit_size;
info->interpolation = interpolation;
info->centroid = centroid;
info->sample = sample;
info->patch = patch;
}
comp++;
/* We need to do some special handling for doubles as dvec3 and
* dvec4 consume two consecutive locations. We don't need to
* worry about components beginning at anything other than 0 as
* the spec does not allow this for dvec3 and dvec4.
*/
if (comp == 4 && last_comp > 4) {
last_comp = last_comp - 4;
/* Bump location index and reset the component index */
location++;
comp = 0;
component = 0;
}
}
location++;
}
return true;
}
static bool
validate_explicit_variable_location(struct gl_context *ctx,
struct explicit_location_info explicit_locations[][4],
ir_variable *var,
gl_shader_program *prog,
gl_linked_shader *sh)
{
const glsl_type *type = get_varying_type(var, sh->Stage);
unsigned num_elements = type->count_attribute_slots(false);
unsigned idx = compute_variable_location_slot(var, sh->Stage);
unsigned slot_limit = idx + num_elements;
/* Vertex shader inputs and fragment shader outputs are validated in
* assign_attribute_or_color_locations() so we should not attempt to
* validate them again here.
*/
unsigned slot_max;
if (var->data.mode == ir_var_shader_out) {
assert(sh->Stage != MESA_SHADER_FRAGMENT);
slot_max =
ctx->Const.Program[sh->Stage].MaxOutputComponents / 4;
} else {
assert(var->data.mode == ir_var_shader_in);
assert(sh->Stage != MESA_SHADER_VERTEX);
slot_max =
ctx->Const.Program[sh->Stage].MaxInputComponents / 4;
}
if (slot_limit > slot_max) {
linker_error(prog,
"Invalid location %u in %s shader\n",
idx, _mesa_shader_stage_to_string(sh->Stage));
return false;
}
const glsl_type *type_without_array = type->without_array();
if (type_without_array->is_interface()) {
for (unsigned i = 0; i < type_without_array->length; i++) {
glsl_struct_field *field = &type_without_array->fields.structure[i];
unsigned field_location = field->location -
(field->patch ? VARYING_SLOT_PATCH0 : VARYING_SLOT_VAR0);
if (!check_location_aliasing(explicit_locations, var,
field_location,
0, field_location + 1,
field->type,
field->interpolation,
field->centroid,
field->sample,
field->patch,
prog, sh->Stage)) {
return false;
}
}
} else if (!check_location_aliasing(explicit_locations, var,
idx, var->data.location_frac,
slot_limit, type,
var->data.interpolation,
var->data.centroid,
var->data.sample,
var->data.patch,
prog, sh->Stage)) {
return false;
}
return true;
}
/**
* Validate explicit locations for the inputs to the first stage and the
* outputs of the last stage in an SSO program (everything in between is
* validated in cross_validate_outputs_to_inputs).
*/
void
validate_sso_explicit_locations(struct gl_context *ctx,
struct gl_shader_program *prog,
gl_shader_stage first_stage,
gl_shader_stage last_stage)
{
assert(prog->SeparateShader);
/* VS inputs and FS outputs are validated in
* assign_attribute_or_color_locations()
*/
bool validate_first_stage = first_stage != MESA_SHADER_VERTEX;
bool validate_last_stage = last_stage != MESA_SHADER_FRAGMENT;
if (!validate_first_stage && !validate_last_stage)
return;
struct explicit_location_info explicit_locations[MAX_VARYING][4];
gl_shader_stage stages[2] = { first_stage, last_stage };
bool validate_stage[2] = { validate_first_stage, validate_last_stage };
ir_variable_mode var_direction[2] = { ir_var_shader_in, ir_var_shader_out };
for (unsigned i = 0; i < 2; i++) {
if (!validate_stage[i])
continue;
gl_shader_stage stage = stages[i];
gl_linked_shader *sh = prog->_LinkedShaders[stage];
assert(sh);
memset(explicit_locations, 0, sizeof(explicit_locations));
foreach_in_list(ir_instruction, node, sh->ir) {
ir_variable *const var = node->as_variable();
if (var == NULL ||
!var->data.explicit_location ||
var->data.location < VARYING_SLOT_VAR0 ||
var->data.mode != var_direction[i])
continue;
if (!validate_explicit_variable_location(
ctx, explicit_locations, var, prog, sh)) {
return;
}
}
}
}
/**
* Validate that outputs from one stage match inputs of another
*/
void
cross_validate_outputs_to_inputs(struct gl_context *ctx,
struct gl_shader_program *prog,
gl_linked_shader *producer,
gl_linked_shader *consumer)
{
glsl_symbol_table parameters;
struct explicit_location_info explicit_locations[MAX_VARYING][4] = { 0 };
/* Find all shader outputs in the "producer" stage.
*/
foreach_in_list(ir_instruction, node, producer->ir) {
ir_variable *const var = node->as_variable();
if (var == NULL || var->data.mode != ir_var_shader_out)
continue;
if (!var->data.explicit_location
|| var->data.location < VARYING_SLOT_VAR0)
parameters.add_variable(var);
else {
/* User-defined varyings with explicit locations are handled
* differently because they do not need to have matching names.
*/
if (!validate_explicit_variable_location(ctx,
explicit_locations,
var, prog, producer)) {
return;
}
}
}
/* Find all shader inputs in the "consumer" stage. Any variables that have
* matching outputs already in the symbol table must have the same type and
* qualifiers.
*
* Exception: if the consumer is the geometry shader, then the inputs
* should be arrays and the type of the array element should match the type
* of the corresponding producer output.
*/
foreach_in_list(ir_instruction, node, consumer->ir) {
ir_variable *const input = node->as_variable();
if (input == NULL || input->data.mode != ir_var_shader_in)
continue;
if (strcmp(input->name, "gl_Color") == 0 && input->data.used) {
const ir_variable *const front_color =
parameters.get_variable("gl_FrontColor");
const ir_variable *const back_color =
parameters.get_variable("gl_BackColor");
cross_validate_front_and_back_color(ctx, prog, input,
front_color, back_color,
consumer->Stage, producer->Stage);
} else if (strcmp(input->name, "gl_SecondaryColor") == 0 && input->data.used) {
const ir_variable *const front_color =
parameters.get_variable("gl_FrontSecondaryColor");
const ir_variable *const back_color =
parameters.get_variable("gl_BackSecondaryColor");
cross_validate_front_and_back_color(ctx, prog, input,
front_color, back_color,
consumer->Stage, producer->Stage);
} else {
/* The rules for connecting inputs and outputs change in the presence
* of explicit locations. In this case, we no longer care about the
* names of the variables. Instead, we care only about the
* explicitly assigned location.
*/
ir_variable *output = NULL;
if (input->data.explicit_location
&& input->data.location >= VARYING_SLOT_VAR0) {
const glsl_type *type = get_varying_type(input, consumer->Stage);
unsigned num_elements = type->count_attribute_slots(false);
unsigned idx =
compute_variable_location_slot(input, consumer->Stage);
unsigned slot_limit = idx + num_elements;
while (idx < slot_limit) {
if (idx >= MAX_VARYING) {
linker_error(prog,
"Invalid location %u in %s shader\n", idx,
_mesa_shader_stage_to_string(consumer->Stage));
return;
}
output = explicit_locations[idx][input->data.location_frac].var;
if (output == NULL) {
/* A linker failure should only happen when there is no
* output declaration and there is Static Use of the
* declared input.
*/
if (input->data.used) {
linker_error(prog,
"%s shader input `%s' with explicit location "
"has no matching output\n",
_mesa_shader_stage_to_string(consumer->Stage),
input->name);
break;
}
} else if (input->data.location != output->data.location) {
linker_error(prog,
"%s shader input `%s' with explicit location "
"has no matching output\n",
_mesa_shader_stage_to_string(consumer->Stage),
input->name);
break;
}
idx++;
}
} else {
output = parameters.get_variable(input->name);
}
if (output != NULL) {
/* Interface blocks have their own validation elsewhere so don't
* try validating them here.
*/
if (!(input->get_interface_type() &&
output->get_interface_type()))
cross_validate_types_and_qualifiers(ctx, prog, input, output,
consumer->Stage,
producer->Stage);
} else {
/* Check for input vars with unmatched output vars in prev stage
* taking into account that interface blocks could have a matching
* output but with different name, so we ignore them.
*/
assert(!input->data.assigned);
if (input->data.used && !input->get_interface_type() &&
!input->data.explicit_location)
linker_error(prog,
"%s shader input `%s' "
"has no matching output in the previous stage\n",
_mesa_shader_stage_to_string(consumer->Stage),
input->name);
}
}
}
}
/**
* Demote shader inputs and outputs that are not used in other stages, and
* remove them via dead code elimination.
*/
static void
remove_unused_shader_inputs_and_outputs(bool is_separate_shader_object,
gl_linked_shader *sh,
enum ir_variable_mode mode)
{
if (is_separate_shader_object)
return;
foreach_in_list(ir_instruction, node, sh->ir) {
ir_variable *const var = node->as_variable();
if (var == NULL || var->data.mode != int(mode))
continue;
/* A shader 'in' or 'out' variable is only really an input or output if
* its value is used by other shader stages. This will cause the
* variable to have a location assigned.
*/
if (var->data.is_unmatched_generic_inout && !var->data.is_xfb_only) {
assert(var->data.mode != ir_var_temporary);
/* Assign zeros to demoted inputs to allow more optimizations. */
if (var->data.mode == ir_var_shader_in && !var->constant_value)
var->constant_value = ir_constant::zero(var, var->type);
var->data.mode = ir_var_auto;
}
}
/* Eliminate code that is now dead due to unused inputs/outputs being
* demoted.
*/
while (do_dead_code(sh->ir, false))
;
}
/**
* Initialize this object based on a string that was passed to
* glTransformFeedbackVaryings.
*
* If the input is mal-formed, this call still succeeds, but it sets
* this->var_name to a mal-formed input, so tfeedback_decl::find_output_var()
* will fail to find any matching variable.
*/
void
tfeedback_decl::init(struct gl_context *ctx, const void *mem_ctx,
const char *input)
{
/* We don't have to be pedantic about what is a valid GLSL variable name,
* because any variable with an invalid name can't exist in the IR anyway.
*/
this->location = -1;
this->orig_name = input;
this->lowered_builtin_array_variable = none;
this->skip_components = 0;
this->next_buffer_separator = false;
this->matched_candidate = NULL;
this->stream_id = 0;
this->buffer = 0;
this->offset = 0;
if (ctx->Extensions.ARB_transform_feedback3) {
/* Parse gl_NextBuffer. */
if (strcmp(input, "gl_NextBuffer") == 0) {
this->next_buffer_separator = true;
return;
}
/* Parse gl_SkipComponents. */
if (strcmp(input, "gl_SkipComponents1") == 0)
this->skip_components = 1;
else if (strcmp(input, "gl_SkipComponents2") == 0)
this->skip_components = 2;
else if (strcmp(input, "gl_SkipComponents3") == 0)
this->skip_components = 3;
else if (strcmp(input, "gl_SkipComponents4") == 0)
this->skip_components = 4;
if (this->skip_components)
return;
}
/* Parse a declaration. */
const char *base_name_end;
long subscript = parse_program_resource_name(input, &base_name_end);
this->var_name = ralloc_strndup(mem_ctx, input, base_name_end - input);
if (this->var_name == NULL) {
_mesa_error_no_memory(__func__);
return;
}
if (subscript >= 0) {
this->array_subscript = subscript;
this->is_subscripted = true;
} else {
this->is_subscripted = false;
}
/* For drivers that lower gl_ClipDistance to gl_ClipDistanceMESA, this
* class must behave specially to account for the fact that gl_ClipDistance
* is converted from a float[8] to a vec4[2].
*/
if (ctx->Const.ShaderCompilerOptions[MESA_SHADER_VERTEX].LowerCombinedClipCullDistance &&
strcmp(this->var_name, "gl_ClipDistance") == 0) {
this->lowered_builtin_array_variable = clip_distance;
}
if (ctx->Const.ShaderCompilerOptions[MESA_SHADER_VERTEX].LowerCombinedClipCullDistance &&
strcmp(this->var_name, "gl_CullDistance") == 0) {
this->lowered_builtin_array_variable = cull_distance;
}
if (ctx->Const.LowerTessLevel &&
(strcmp(this->var_name, "gl_TessLevelOuter") == 0))
this->lowered_builtin_array_variable = tess_level_outer;
if (ctx->Const.LowerTessLevel &&
(strcmp(this->var_name, "gl_TessLevelInner") == 0))
this->lowered_builtin_array_variable = tess_level_inner;
}
/**
* Determine whether two tfeedback_decl objects refer to the same variable and
* array index (if applicable).
*/
bool
tfeedback_decl::is_same(const tfeedback_decl &x, const tfeedback_decl &y)
{
assert(x.is_varying() && y.is_varying());
if (strcmp(x.var_name, y.var_name) != 0)
return false;
if (x.is_subscripted != y.is_subscripted)
return false;
if (x.is_subscripted && x.array_subscript != y.array_subscript)
return false;
return true;
}
/**
* Assign a location and stream ID for this tfeedback_decl object based on the
* transform feedback candidate found by find_candidate.
*
* If an error occurs, the error is reported through linker_error() and false
* is returned.
*/
bool
tfeedback_decl::assign_location(struct gl_context *ctx,
struct gl_shader_program *prog)
{
assert(this->is_varying());
unsigned fine_location
= this->matched_candidate->toplevel_var->data.location * 4
+ this->matched_candidate->toplevel_var->data.location_frac
+ this->matched_candidate->offset;
const unsigned dmul =
this->matched_candidate->type->without_array()->is_64bit() ? 2 : 1;
if (this->matched_candidate->type->is_array()) {
/* Array variable */
const unsigned matrix_cols =
this->matched_candidate->type->fields.array->matrix_columns;
const unsigned vector_elements =
this->matched_candidate->type->fields.array->vector_elements;
unsigned actual_array_size;
switch (this->lowered_builtin_array_variable) {
case clip_distance:
actual_array_size = prog->last_vert_prog ?
prog->last_vert_prog->info.clip_distance_array_size : 0;
break;
case cull_distance:
actual_array_size = prog->last_vert_prog ?
prog->last_vert_prog->info.cull_distance_array_size : 0;
break;
case tess_level_outer:
actual_array_size = 4;
break;
case tess_level_inner:
actual_array_size = 2;
break;
case none:
default:
actual_array_size = this->matched_candidate->type->array_size();
break;
}
if (this->is_subscripted) {
/* Check array bounds. */
if (this->array_subscript >= actual_array_size) {
linker_error(prog, "Transform feedback varying %s has index "
"%i, but the array size is %u.",
this->orig_name, this->array_subscript,
actual_array_size);
return false;
}
unsigned array_elem_size = this->lowered_builtin_array_variable ?
1 : vector_elements * matrix_cols * dmul;
fine_location += array_elem_size * this->array_subscript;
this->size = 1;
} else {
this->size = actual_array_size;
}
this->vector_elements = vector_elements;
this->matrix_columns = matrix_cols;
if (this->lowered_builtin_array_variable)
this->type = GL_FLOAT;
else
this->type = this->matched_candidate->type->fields.array->gl_type;
} else {
/* Regular variable (scalar, vector, or matrix) */
if (this->is_subscripted) {
linker_error(prog, "Transform feedback varying %s requested, "
"but %s is not an array.",
this->orig_name, this->var_name);
return false;
}
this->size = 1;
this->vector_elements = this->matched_candidate->type->vector_elements;
this->matrix_columns = this->matched_candidate->type->matrix_columns;
this->type = this->matched_candidate->type->gl_type;
}
this->location = fine_location / 4;
this->location_frac = fine_location % 4;
/* From GL_EXT_transform_feedback:
* A program will fail to link if:
*
* * the total number of components to capture in any varying
* variable in <varyings> is greater than the constant
* MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS_EXT and the
* buffer mode is SEPARATE_ATTRIBS_EXT;
*/
if (prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS &&
this->num_components() >
ctx->Const.MaxTransformFeedbackSeparateComponents) {
linker_error(prog, "Transform feedback varying %s exceeds "
"MAX_TRANSFORM_FEEDBACK_SEPARATE_COMPONENTS.",
this->orig_name);
return false;
}
/* Only transform feedback varyings can be assigned to non-zero streams,
* so assign the stream id here.
*/
this->stream_id = this->matched_candidate->toplevel_var->data.stream;
unsigned array_offset = this->array_subscript * 4 * dmul;
unsigned struct_offset = this->matched_candidate->offset * 4 * dmul;
this->buffer = this->matched_candidate->toplevel_var->data.xfb_buffer;
this->offset = this->matched_candidate->toplevel_var->data.offset +
array_offset + struct_offset;
return true;
}
unsigned
tfeedback_decl::get_num_outputs() const
{
if (!this->is_varying()) {
return 0;
}
return (this->num_components() + this->location_frac + 3)/4;
}
/**
* Update gl_transform_feedback_info to reflect this tfeedback_decl.
*
* If an error occurs, the error is reported through linker_error() and false
* is returned.
*/
bool
tfeedback_decl::store(struct gl_context *ctx, struct gl_shader_program *prog,
struct gl_transform_feedback_info *info,
unsigned buffer, unsigned buffer_index,
const unsigned max_outputs, bool *explicit_stride,
bool has_xfb_qualifiers) const
{
unsigned xfb_offset = 0;
unsigned size = this->size;
/* Handle gl_SkipComponents. */
if (this->skip_components) {
info->Buffers[buffer].Stride += this->skip_components;
size = this->skip_components;
goto store_varying;
}
if (this->next_buffer_separator) {
size = 0;
goto store_varying;
}
if (has_xfb_qualifiers) {
xfb_offset = this->offset / 4;
} else {
xfb_offset = info->Buffers[buffer].Stride;
}
info->Varyings[info->NumVarying].Offset = xfb_offset * 4;
{
unsigned location = this->location;
unsigned location_frac = this->location_frac;
unsigned num_components = this->num_components();
while (num_components > 0) {
unsigned output_size = MIN2(num_components, 4 - location_frac);
assert((info->NumOutputs == 0 && max_outputs == 0) ||
info->NumOutputs < max_outputs);
/* From the ARB_enhanced_layouts spec:
*
* "If such a block member or variable is not written during a shader
* invocation, the buffer contents at the assigned offset will be
* undefined. Even if there are no static writes to a variable or
* member that is assigned a transform feedback offset, the space is
* still allocated in the buffer and still affects the stride."
*/
if (this->is_varying_written()) {
info->Outputs[info->NumOutputs].ComponentOffset = location_frac;
info->Outputs[info->NumOutputs].OutputRegister = location;
info->Outputs[info->NumOutputs].NumComponents = output_size;
info->Outputs[info->NumOutputs].StreamId = stream_id;
info->Outputs[info->NumOutputs].OutputBuffer = buffer;
info->Outputs[info->NumOutputs].DstOffset = xfb_offset;
++info->NumOutputs;
}
info->Buffers[buffer].Stream = this->stream_id;
xfb_offset += output_size;
num_components -= output_size;
location++;
location_frac = 0;
}
}
if (explicit_stride && explicit_stride[buffer]) {
if (this->is_64bit() && info->Buffers[buffer].Stride % 2) {
linker_error(prog, "invalid qualifier xfb_stride=%d must be a "
"multiple of 8 as its applied to a type that is or "
"contains a double.",
info->Buffers[buffer].Stride * 4);
return false;
}
if (xfb_offset > info->Buffers[buffer].Stride) {
linker_error(prog, "xfb_offset (%d) overflows xfb_stride (%d) for "
"buffer (%d)", xfb_offset * 4,
info->Buffers[buffer].Stride * 4, buffer);
return false;
}
} else {
info->Buffers[buffer].Stride = xfb_offset;
}
/* From GL_EXT_transform_feedback:
* A program will fail to link if:
*
* * the total number of components to capture is greater than
* the constant MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS_EXT
* and the buffer mode is INTERLEAVED_ATTRIBS_EXT.
*
* From GL_ARB_enhanced_layouts:
*
* "The resulting stride (implicit or explicit) must be less than or
* equal to the implementation-dependent constant
* gl_MaxTransformFeedbackInterleavedComponents."
*/
if ((prog->TransformFeedback.BufferMode == GL_INTERLEAVED_ATTRIBS ||
has_xfb_qualifiers) &&
info->Buffers[buffer].Stride >
ctx->Const.MaxTransformFeedbackInterleavedComponents) {
linker_error(prog, "The MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS "
"limit has been exceeded.");
return false;
}
store_varying:
info->Varyings[info->NumVarying].Name = ralloc_strdup(prog,
this->orig_name);
info->Varyings[info->NumVarying].Type = this->type;
info->Varyings[info->NumVarying].Size = size;
info->Varyings[info->NumVarying].BufferIndex = buffer_index;
info->NumVarying++;
info->Buffers[buffer].NumVaryings++;
return true;
}
const tfeedback_candidate *
tfeedback_decl::find_candidate(gl_shader_program *prog,
hash_table *tfeedback_candidates)
{
const char *name = this->var_name;
switch (this->lowered_builtin_array_variable) {
case none:
name = this->var_name;
break;
case clip_distance:
name = "gl_ClipDistanceMESA";
break;
case cull_distance:
name = "gl_CullDistanceMESA";
break;
case tess_level_outer:
name = "gl_TessLevelOuterMESA";
break;
case tess_level_inner:
name = "gl_TessLevelInnerMESA";
break;
}
hash_entry *entry = _mesa_hash_table_search(tfeedback_candidates, name);
this->matched_candidate = entry ?
(const tfeedback_candidate *) entry->data : NULL;
if (!this->matched_candidate) {
/* From GL_EXT_transform_feedback:
* A program will fail to link if:
*
* * any variable name specified in the <varyings> array is not
* declared as an output in the geometry shader (if present) or
* the vertex shader (if no geometry shader is present);
*/
linker_error(prog, "Transform feedback varying %s undeclared.",
this->orig_name);
}
return this->matched_candidate;
}
/**
* Parse all the transform feedback declarations that were passed to
* glTransformFeedbackVaryings() and store them in tfeedback_decl objects.
*
* If an error occurs, the error is reported through linker_error() and false
* is returned.
*/
static bool
parse_tfeedback_decls(struct gl_context *ctx, struct gl_shader_program *prog,
const void *mem_ctx, unsigned num_names,
char **varying_names, tfeedback_decl *decls)
{
for (unsigned i = 0; i < num_names; ++i) {
decls[i].init(ctx, mem_ctx, varying_names[i]);
if (!decls[i].is_varying())
continue;
/* From GL_EXT_transform_feedback:
* A program will fail to link if:
*
* * any two entries in the <varyings> array specify the same varying
* variable;
*
* We interpret this to mean "any two entries in the <varyings> array
* specify the same varying variable and array index", since transform
* feedback of arrays would be useless otherwise.
*/
for (unsigned j = 0; j < i; ++j) {
if (decls[j].is_varying()) {
if (tfeedback_decl::is_same(decls[i], decls[j])) {
linker_error(prog, "Transform feedback varying %s specified "
"more than once.", varying_names[i]);
return false;
}
}
}
}
return true;
}
static int
cmp_xfb_offset(const void * x_generic, const void * y_generic)
{
tfeedback_decl *x = (tfeedback_decl *) x_generic;
tfeedback_decl *y = (tfeedback_decl *) y_generic;
if (x->get_buffer() != y->get_buffer())
return x->get_buffer() - y->get_buffer();
return x->get_offset() - y->get_offset();
}
/**
* Store transform feedback location assignments into
* prog->sh.LinkedTransformFeedback based on the data stored in
* tfeedback_decls.
*
* If an error occurs, the error is reported through linker_error() and false
* is returned.
*/
static bool
store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog,
unsigned num_tfeedback_decls,
tfeedback_decl *tfeedback_decls, bool has_xfb_qualifiers)
{
if (!prog->last_vert_prog)
return true;
/* Make sure MaxTransformFeedbackBuffers is less than 32 so the bitmask for
* tracking the number of buffers doesn't overflow.
*/
assert(ctx->Const.MaxTransformFeedbackBuffers < 32);
bool separate_attribs_mode =
prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS;
struct gl_program *xfb_prog = prog->last_vert_prog;
xfb_prog->sh.LinkedTransformFeedback =
rzalloc(xfb_prog, struct gl_transform_feedback_info);
/* The xfb_offset qualifier does not have to be used in increasing order
* however some drivers expect to receive the list of transform feedback
* declarations in order so sort it now for convenience.
*/
if (has_xfb_qualifiers) {
qsort(tfeedback_decls, num_tfeedback_decls, sizeof(*tfeedback_decls),
cmp_xfb_offset);
}
xfb_prog->sh.LinkedTransformFeedback->Varyings =
rzalloc_array(xfb_prog, struct gl_transform_feedback_varying_info,
num_tfeedback_decls);
unsigned num_outputs = 0;
for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
if (tfeedback_decls[i].is_varying_written())
num_outputs += tfeedback_decls[i].get_num_outputs();
}
xfb_prog->sh.LinkedTransformFeedback->Outputs =
rzalloc_array(xfb_prog, struct gl_transform_feedback_output,
num_outputs);
unsigned num_buffers = 0;
unsigned buffers = 0;
if (!has_xfb_qualifiers && separate_attribs_mode) {
/* GL_SEPARATE_ATTRIBS */
for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
if (!tfeedback_decls[i].store(ctx, prog,
xfb_prog->sh.LinkedTransformFeedback,
num_buffers, num_buffers, num_outputs,
NULL, has_xfb_qualifiers))
return false;
buffers |= 1 << num_buffers;
num_buffers++;
}
}
else {
/* GL_INVERLEAVED_ATTRIBS */
int buffer_stream_id = -1;
unsigned buffer =
num_tfeedback_decls ? tfeedback_decls[0].get_buffer() : 0;
bool explicit_stride[MAX_FEEDBACK_BUFFERS] = { false };
/* Apply any xfb_stride global qualifiers */
if (has_xfb_qualifiers) {
for (unsigned j = 0; j < MAX_FEEDBACK_BUFFERS; j++) {
if (prog->TransformFeedback.BufferStride[j]) {
explicit_stride[j] = true;
xfb_prog->sh.LinkedTransformFeedback->Buffers[j].Stride =
prog->TransformFeedback.BufferStride[j] / 4;
}
}
}
for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
if (has_xfb_qualifiers &&
buffer != tfeedback_decls[i].get_buffer()) {
/* we have moved to the next buffer so reset stream id */
buffer_stream_id = -1;
num_buffers++;
}
if (tfeedback_decls[i].is_next_buffer_separator()) {
if (!tfeedback_decls[i].store(ctx, prog,
xfb_prog->sh.LinkedTransformFeedback,
buffer, num_buffers, num_outputs,
explicit_stride, has_xfb_qualifiers))
return false;
num_buffers++;
buffer_stream_id = -1;
continue;
}
if (has_xfb_qualifiers) {
buffer = tfeedback_decls[i].get_buffer();
} else {
buffer = num_buffers;
}
if (tfeedback_decls[i].is_varying()) {
if (buffer_stream_id == -1) {
/* First varying writing to this buffer: remember its stream */
buffer_stream_id = (int) tfeedback_decls[i].get_stream_id();
/* Only mark a buffer as active when there is a varying
* attached to it. This behaviour is based on a revised version
* of section 13.2.2 of the GL 4.6 spec.
*/
buffers |= 1 << buffer;
} else if (buffer_stream_id !=
(int) tfeedback_decls[i].get_stream_id()) {
/* Varying writes to the same buffer from a different stream */
linker_error(prog,
"Transform feedback can't capture varyings belonging "
"to different vertex streams in a single buffer. "
"Varying %s writes to buffer from stream %u, other "
"varyings in the same buffer write from stream %u.",
tfeedback_decls[i].name(),
tfeedback_decls[i].get_stream_id(),
buffer_stream_id);
return false;
}
}
if (!tfeedback_decls[i].store(ctx, prog,
xfb_prog->sh.LinkedTransformFeedback,
buffer, num_buffers, num_outputs,
explicit_stride, has_xfb_qualifiers))
return false;
}
}
assert(xfb_prog->sh.LinkedTransformFeedback->NumOutputs == num_outputs);
xfb_prog->sh.LinkedTransformFeedback->ActiveBuffers = buffers;
return true;
}
namespace {
/**
* Data structure recording the relationship between outputs of one shader
* stage (the "producer") and inputs of another (the "consumer").
*/
class varying_matches
{
public:
varying_matches(bool disable_varying_packing, bool xfb_enabled,
bool enhanced_layouts_enabled,
gl_shader_stage producer_stage,
gl_shader_stage consumer_stage);
~varying_matches();
void record(ir_variable *producer_var, ir_variable *consumer_var);
unsigned assign_locations(struct gl_shader_program *prog,
uint8_t components[],
uint64_t reserved_slots);
void store_locations() const;
private:
bool is_varying_packing_safe(const glsl_type *type,
const ir_variable *var) const;
/**
* If true, this driver disables varying packing, so all varyings need to
* be aligned on slot boundaries, and take up a number of slots equal to
* their number of matrix columns times their array size.
*
* Packing may also be disabled because our current packing method is not
* safe in SSO or versions of OpenGL where interpolation qualifiers are not
* guaranteed to match across stages.
*/
const bool disable_varying_packing;
/**
* If true, this driver has transform feedback enabled. The transform
* feedback code requires at least some packing be done even when varying
* packing is disabled, fortunately where transform feedback requires
* packing it's safe to override the disabled setting. See
* is_varying_packing_safe().
*/
const bool xfb_enabled;
const bool enhanced_layouts_enabled;
/**
* Enum representing the order in which varyings are packed within a
* packing class.
*
* Currently we pack vec4's first, then vec2's, then scalar values, then
* vec3's. This order ensures that the only vectors that are at risk of
* having to be "double parked" (split between two adjacent varying slots)
* are the vec3's.
*/
enum packing_order_enum {
PACKING_ORDER_VEC4,
PACKING_ORDER_VEC2,
PACKING_ORDER_SCALAR,
PACKING_ORDER_VEC3,
};
static unsigned compute_packing_class(const ir_variable *var);
static packing_order_enum compute_packing_order(const ir_variable *var);
static int match_comparator(const void *x_generic, const void *y_generic);
static int xfb_comparator(const void *x_generic, const void *y_generic);
/**
* Structure recording the relationship between a single producer output
* and a single consumer input.
*/
struct match {
/**
* Packing class for this varying, computed by compute_packing_class().
*/
unsigned packing_class;
/**
* Packing order for this varying, computed by compute_packing_order().
*/
packing_order_enum packing_order;
unsigned num_components;
/**
* The output variable in the producer stage.
*/
ir_variable *producer_var;
/**
* The input variable in the consumer stage.
*/
ir_variable *consumer_var;
/**
* The location which has been assigned for this varying. This is
* expressed in multiples of a float, with the first generic varying
* (i.e. the one referred to by VARYING_SLOT_VAR0) represented by the
* value 0.
*/
unsigned generic_location;
} *matches;
/**
* The number of elements in the \c matches array that are currently in
* use.
*/
unsigned num_matches;
/**
* The number of elements that were set aside for the \c matches array when
* it was allocated.
*/
unsigned matches_capacity;
gl_shader_stage producer_stage;
gl_shader_stage consumer_stage;
};
} /* anonymous namespace */
varying_matches::varying_matches(bool disable_varying_packing,
bool xfb_enabled,
bool enhanced_layouts_enabled,
gl_shader_stage producer_stage,
gl_shader_stage consumer_stage)
: disable_varying_packing(disable_varying_packing),
xfb_enabled(xfb_enabled),
enhanced_layouts_enabled(enhanced_layouts_enabled),
producer_stage(producer_stage),
consumer_stage(consumer_stage)
{
/* Note: this initial capacity is rather arbitrarily chosen to be large
* enough for many cases without wasting an unreasonable amount of space.
* varying_matches::record() will resize the array if there are more than
* this number of varyings.
*/
this->matches_capacity = 8;
this->matches = (match *)
malloc(sizeof(*this->matches) * this->matches_capacity);
this->num_matches = 0;
}
varying_matches::~varying_matches()
{
free(this->matches);
}
/**
* Packing is always safe on individual arrays, structures, and matrices. It
* is also safe if the varying is only used for transform feedback.
*/
bool
varying_matches::is_varying_packing_safe(const glsl_type *type,
const ir_variable *var) const
{
if (consumer_stage == MESA_SHADER_TESS_EVAL ||
consumer_stage == MESA_SHADER_TESS_CTRL ||
producer_stage == MESA_SHADER_TESS_CTRL)
return false;
return xfb_enabled && (type->is_array() || type->is_record() ||
type->is_matrix() || var->data.is_xfb_only);
}
/**
* Record the given producer/consumer variable pair in the list of variables
* that should later be assigned locations.
*
* It is permissible for \c consumer_var to be NULL (this happens if a
* variable is output by the producer and consumed by transform feedback, but
* not consumed by the consumer).
*
* If \c producer_var has already been paired up with a consumer_var, or
* producer_var is part of fixed pipeline functionality (and hence already has
* a location assigned), this function has no effect.
*
* Note: as a side effect this function may change the interpolation type of
* \c producer_var, but only when the change couldn't possibly affect
* rendering.
*/
void
varying_matches::record(ir_variable *producer_var, ir_variable *consumer_var)
{
assert(producer_var != NULL || consumer_var != NULL);
if ((producer_var && (!producer_var->data.is_unmatched_generic_inout ||
producer_var->data.explicit_location)) ||
(consumer_var && (!consumer_var->data.is_unmatched_generic_inout ||
consumer_var->data.explicit_location))) {
/* Either a location already exists for this variable (since it is part
* of fixed functionality), or it has already been recorded as part of a
* previous match.
*/
return;
}
bool needs_flat_qualifier = consumer_var == NULL &&
(producer_var->type->contains_integer() ||
producer_var->type->contains_double());
if (!disable_varying_packing &&
(needs_flat_qualifier ||
(consumer_stage != MESA_SHADER_NONE && consumer_stage != MESA_SHADER_FRAGMENT))) {
/* Since this varying is not being consumed by the fragment shader, its
* interpolation type varying cannot possibly affect rendering.
* Also, this variable is non-flat and is (or contains) an integer
* or a double.
* If the consumer stage is unknown, don't modify the interpolation
* type as it could affect rendering later with separate shaders.
*
* lower_packed_varyings requires all integer varyings to flat,
* regardless of where they appear. We can trivially satisfy that
* requirement by changing the interpolation type to flat here.
*/
if (producer_var) {
producer_var->data.centroid = false;
producer_var->data.sample = false;
producer_var->data.interpolation = INTERP_MODE_FLAT;
}
if (consumer_var) {
consumer_var->data.centroid = false;
consumer_var->data.sample = false;
consumer_var->data.interpolation = INTERP_MODE_FLAT;
}
}
if (this->num_matches == this->matches_capacity) {
this->matches_capacity *= 2;
this->matches = (match *)
realloc(this->matches,
sizeof(*this->matches) * this->matches_capacity);
}
/* We must use the consumer to compute the packing class because in GL4.4+
* there is no guarantee interpolation qualifiers will match across stages.
*
* From Section 4.5 (Interpolation Qualifiers) of the GLSL 4.30 spec:
*
* "The type and presence of interpolation qualifiers of variables with
* the same name declared in all linked shaders for the same cross-stage
* interface must match, otherwise the link command will fail.
*
* When comparing an output from one stage to an input of a subsequent
* stage, the input and output don't match if their interpolation
* qualifiers (or lack thereof) are not the same."
*
* This text was also in at least revison 7 of the 4.40 spec but is no
* longer in revision 9 and not in the 4.50 spec.
*/
const ir_variable *const var = (consumer_var != NULL)
? consumer_var : producer_var;
const gl_shader_stage stage = (consumer_var != NULL)
? consumer_stage : producer_stage;
const glsl_type *type = get_varying_type(var, stage);
if (producer_var && consumer_var &&
consumer_var->data.must_be_shader_input) {
producer_var->data.must_be_shader_input = 1;
}
this->matches[this->num_matches].packing_class
= this->compute_packing_class(var);
this->matches[this->num_matches].packing_order
= this->compute_packing_order(var);
if ((this->disable_varying_packing && !is_varying_packing_safe(type, var)) ||
var->data.must_be_shader_input) {
unsigned slots = type->count_attribute_slots(false);
this->matches[this->num_matches].num_components = slots * 4;
} else {
this->matches[this->num_matches].num_components
= type->component_slots();
}
this->matches[this->num_matches].producer_var = producer_var;
this->matches[this->num_matches].consumer_var = consumer_var;
this->num_matches++;
if (producer_var)
producer_var->data.is_unmatched_generic_inout = 0;
if (consumer_var)
consumer_var->data.is_unmatched_generic_inout = 0;
}
/**
* Choose locations for all of the variable matches that were previously
* passed to varying_matches::record().
* \param components returns array[slot] of number of components used
* per slot (1, 2, 3 or 4)
* \param reserved_slots bitmask indicating which varying slots are already
* allocated
* \return number of slots (4-element vectors) allocated
*/
unsigned
varying_matches::assign_locations(struct gl_shader_program *prog,
uint8_t components[],
uint64_t reserved_slots)
{
/* If packing has been disabled then we cannot safely sort the varyings by
* class as it may mean we are using a version of OpenGL where
* interpolation qualifiers are not guaranteed to be matching across
* shaders, sorting in this case could result in mismatching shader
* interfaces.
* When packing is disabled the sort orders varyings used by transform
* feedback first, but also depends on *undefined behaviour* of qsort to
* reverse the order of the varyings. See: xfb_comparator().
*/
if (!this->disable_varying_packing) {
/* Sort varying matches into an order that makes them easy to pack. */
qsort(this->matches, this->num_matches, sizeof(*this->matches),
&varying_matches::match_comparator);
} else {
/* Only sort varyings that are only used by transform feedback. */
qsort(this->matches, this->num_matches, sizeof(*this->matches),
&varying_matches::xfb_comparator);
}
unsigned generic_location = 0;
unsigned generic_patch_location = MAX_VARYING*4;
bool previous_var_xfb_only = false;
unsigned previous_packing_class = ~0u;
/* For tranform feedback separate mode, we know the number of attributes
* is <= the number of buffers. So packing isn't critical. In fact,
* packing vec3 attributes can cause trouble because splitting a vec3
* effectively creates an additional transform feedback output. The
* extra TFB output may exceed device driver limits.
*/
const bool dont_pack_vec3 =
(prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS &&
prog->TransformFeedback.NumVarying > 0);
for (unsigned i = 0; i < this->num_matches; i++) {
unsigned *location = &generic_location;
const ir_variable *var;
const glsl_type *type;
bool is_vertex_input = false;
if (matches[i].consumer_var) {
var = matches[i].consumer_var;
type = get_varying_type(var, consumer_stage);
if (consumer_stage == MESA_SHADER_VERTEX)
is_vertex_input = true;
} else {
var = matches[i].producer_var;
type = get_varying_type(var, producer_stage);
}
if (var->data.patch)
location = &generic_patch_location;
/* Advance to the next slot if this varying has a different packing
* class than the previous one, and we're not already on a slot
* boundary.
*
* Also advance to the next slot if packing is disabled. This makes sure
* we don't assign varyings the same locations which is possible
* because we still pack individual arrays, records and matrices even
* when packing is disabled. Note we don't advance to the next slot if
* we can pack varyings together that are only used for transform
* feedback.
*/
if (var->data.must_be_shader_input ||
(this->disable_varying_packing &&
!(previous_var_xfb_only && var->data.is_xfb_only)) ||
(previous_packing_class != this->matches[i].packing_class) ||
(this->matches[i].packing_order == PACKING_ORDER_VEC3 &&
dont_pack_vec3)) {
*location = ALIGN(*location, 4);
}
previous_var_xfb_only = var->data.is_xfb_only;
previous_packing_class = this->matches[i].packing_class;
/* The number of components taken up by this variable. For vertex shader
* inputs, we use the number of slots * 4, as they have different
* counting rules.
*/
unsigned num_components = is_vertex_input ?
type->count_attribute_slots(is_vertex_input) * 4 :
this->matches[i].num_components;
/* The last slot for this variable, inclusive. */
unsigned slot_end = *location + num_components - 1;
/* FIXME: We could be smarter in the below code and loop back over
* trying to fill any locations that we skipped because we couldn't pack
* the varying between an explicit location. For now just let the user
* hit the linking error if we run out of room and suggest they use
* explicit locations.
*/
while (slot_end < MAX_VARYING * 4u) {
const unsigned slots = (slot_end / 4u) - (*location / 4u) + 1;
const uint64_t slot_mask = ((1ull << slots) - 1) << (*location / 4u);
assert(slots > 0);
if ((reserved_slots & slot_mask) == 0) {
break;
}
*location = ALIGN(*location + 1, 4);
slot_end = *location + num_components - 1;
}
if (!var->data.patch && slot_end >= MAX_VARYING * 4u) {
linker_error(prog, "insufficient contiguous locations available for "
"%s it is possible an array or struct could not be "
"packed between varyings with explicit locations. Try "
"using an explicit location for arrays and structs.",
var->name);
}
if (slot_end < MAX_VARYINGS_INCL_PATCH * 4u) {
for (unsigned j = *location / 4u; j < slot_end / 4u; j++)
components[j] = 4;
components[slot_end / 4u] = (slot_end & 3) + 1;
}
this->matches[i].generic_location = *location;
*location = slot_end + 1;
}
return (generic_location + 3) / 4;
}
/**
* Update the producer and consumer shaders to reflect the locations
* assignments that were made by varying_matches::assign_locations().
*/
void
varying_matches::store_locations() const
{
/* Check is location needs to be packed with lower_packed_varyings() or if
* we can just use ARB_enhanced_layouts packing.
*/
bool pack_loc[MAX_VARYINGS_INCL_PATCH] = { 0 };
const glsl_type *loc_type[MAX_VARYINGS_INCL_PATCH][4] = { {NULL, NULL} };
for (unsigned i = 0; i < this->num_matches; i++) {
ir_variable *producer_var = this->matches[i].producer_var;
ir_variable *consumer_var = this->matches[i].consumer_var;
unsigned generic_location = this->matches[i].generic_location;
unsigned slot = generic_location / 4;
unsigned offset = generic_location % 4;
if (producer_var) {
producer_var->data.location = VARYING_SLOT_VAR0 + slot;
producer_var->data.location_frac = offset;
}
if (consumer_var) {
assert(consumer_var->data.location == -1);
consumer_var->data.location = VARYING_SLOT_VAR0 + slot;
consumer_var->data.location_frac = offset;
}
/* Find locations suitable for native packing via
* ARB_enhanced_layouts.
*/
if (producer_var && consumer_var) {
if (enhanced_layouts_enabled) {
const glsl_type *type =
get_varying_type(producer_var, producer_stage);
if (type->is_array() || type->is_matrix() || type->is_record() ||
type->is_double()) {
unsigned comp_slots = type->component_slots() + offset;
unsigned slots = comp_slots / 4;
if (comp_slots % 4)
slots += 1;
for (unsigned j = 0; j < slots; j++) {
pack_loc[slot + j] = true;
}
} else if (offset + type->vector_elements > 4) {
pack_loc[slot] = true;
pack_loc[slot + 1] = true;
} else {
loc_type[slot][offset] = type;
}
}
}
}
/* Attempt to use ARB_enhanced_layouts for more efficient packing if
* suitable.
*/
if (enhanced_layouts_enabled) {
for (unsigned i = 0; i < this->num_matches; i++) {
ir_variable *producer_var = this->matches[i].producer_var;
ir_variable *consumer_var = this->matches[i].consumer_var;
unsigned generic_location = this->matches[i].generic_location;
unsigned slot = generic_location / 4;
if (pack_loc[slot] || !producer_var || !consumer_var)
continue;
const glsl_type *type =
get_varying_type(producer_var, producer_stage);
bool type_match = true;
for (unsigned j = 0; j < 4; j++) {
if (loc_type[slot][j]) {
if (type->base_type != loc_type[slot][j]->base_type)
type_match = false;
}
}
if (type_match) {
producer_var->data.explicit_location = 1;
consumer_var->data.explicit_location = 1;
producer_var->data.explicit_component = 1;
consumer_var->data.explicit_component = 1;
}
}
}
}
/**
* Compute the "packing class" of the given varying. This is an unsigned
* integer with the property that two variables in the same packing class can
* be safely backed into the same vec4.
*/
unsigned
varying_matches::compute_packing_class(const ir_variable *var)
{
/* Without help from the back-end, there is no way to pack together
* variables with different interpolation types, because
* lower_packed_varyings must choose exactly one interpolation type for
* each packed varying it creates.
*
* However, we can safely pack together floats, ints, and uints, because:
*
* - varyings of base type "int" and "uint" must use the "flat"
* interpolation type, which can only occur in GLSL 1.30 and above.
*
* - On platforms that support GLSL 1.30 and above, lower_packed_varyings
* can store flat floats as ints without losing any information (using
* the ir_unop_bitcast_* opcodes).
*
* Therefore, the packing class depends only on the interpolation type.
*/
const unsigned interp = var->is_interpolation_flat()
? unsigned(INTERP_MODE_FLAT) : var->data.interpolation;
assert(interp < (1 << 3));
const unsigned packing_class = (interp << 0) |
(var->data.centroid << 3) |
(var->data.sample << 4) |
(var->data.patch << 5) |
(var->data.must_be_shader_input << 6);
return packing_class;
}
/**
* Compute the "packing order" of the given varying. This is a sort key we
* use to determine when to attempt to pack the given varying relative to
* other varyings in the same packing class.
*/
varying_matches::packing_order_enum
varying_matches::compute_packing_order(const ir_variable *var)
{
const glsl_type *element_type = var->type;
while (element_type->is_array()) {
element_type = element_type->fields.array;
}
switch (element_type->component_slots() % 4) {
case 1: return PACKING_ORDER_SCALAR;
case 2: return PACKING_ORDER_VEC2;
case 3: return PACKING_ORDER_VEC3;
case 0: return PACKING_ORDER_VEC4;
default:
assert(!"Unexpected value of vector_elements");
return PACKING_ORDER_VEC4;
}
}
/**
* Comparison function passed to qsort() to sort varyings by packing_class and
* then by packing_order.
*/
int
varying_matches::match_comparator(const void *x_generic, const void *y_generic)
{
const match *x = (const match *) x_generic;
const match *y = (const match *) y_generic;
if (x->packing_class != y->packing_class)
return x->packing_class - y->packing_class;
return x->packing_order - y->packing_order;
}
/**
* Comparison function passed to qsort() to sort varyings used only by
* transform feedback when packing of other varyings is disabled.
*/
int
varying_matches::xfb_comparator(const void *x_generic, const void *y_generic)
{
const match *x = (const match *) x_generic;
if (x->producer_var != NULL && x->producer_var->data.is_xfb_only)
return match_comparator(x_generic, y_generic);
/* FIXME: When the comparator returns 0 it means the elements being
* compared are equivalent. However the qsort documentation says:
*
* "The order of equivalent elements is undefined."
*
* In practice the sort ends up reversing the order of the varyings which
* means locations are also assigned in this reversed order and happens to
* be what we want. This is also whats happening in
* varying_matches::match_comparator().
*/
return 0;
}
/**
* Is the given variable a varying variable to be counted against the
* limit in ctx->Const.MaxVarying?
* This includes variables such as texcoords, colors and generic
* varyings, but excludes variables such as gl_FrontFacing and gl_FragCoord.
*/
static bool
var_counts_against_varying_limit(gl_shader_stage stage, const ir_variable *var)
{
/* Only fragment shaders will take a varying variable as an input */
if (stage == MESA_SHADER_FRAGMENT &&
var->data.mode == ir_var_shader_in) {
switch (var->data.location) {
case VARYING_SLOT_POS:
case VARYING_SLOT_FACE:
case VARYING_SLOT_PNTC:
return false;
default:
return true;
}
}
return false;
}
/**
* Visitor class that generates tfeedback_candidate structs describing all
* possible targets of transform feedback.
*
* tfeedback_candidate structs are stored in the hash table
* tfeedback_candidates, which is passed to the constructor. This hash table
* maps varying names to instances of the tfeedback_candidate struct.
*/
class tfeedback_candidate_generator : public program_resource_visitor
{
public:
tfeedback_candidate_generator(void *mem_ctx,
hash_table *tfeedback_candidates,
gl_shader_stage stage)
: mem_ctx(mem_ctx),
tfeedback_candidates(tfeedback_candidates),
stage(stage),
toplevel_var(NULL),
varying_floats(0)
{
}
void process(ir_variable *var)
{
/* All named varying interface blocks should be flattened by now */
assert(!var->is_interface_instance());
assert(var->data.mode == ir_var_shader_out);
this->toplevel_var = var;
this->varying_floats = 0;
const glsl_type *t =
var->data.from_named_ifc_block ? var->get_interface_type() : var->type;
if (!var->data.patch && stage == MESA_SHADER_TESS_CTRL) {
assert(t->is_array());
t = t->fields.array;
}
program_resource_visitor::process(var, t, false);
}
private:
virtual void visit_field(const glsl_type *type, const char *name,
bool /* row_major */,
const glsl_type * /* record_type */,
const enum glsl_interface_packing,
bool /* last_field */)
{
assert(!type->without_array()->is_record());
assert(!type->without_array()->is_interface());
tfeedback_candidate *candidate
= rzalloc(this->mem_ctx, tfeedback_candidate);
candidate->toplevel_var = this->toplevel_var;
candidate->type = type;
candidate->offset = this->varying_floats;
_mesa_hash_table_insert(this->tfeedback_candidates,
ralloc_strdup(this->mem_ctx, name),
candidate);
this->varying_floats += type->component_slots();
}
/**
* Memory context used to allocate hash table keys and values.
*/
void * const mem_ctx;
/**
* Hash table in which tfeedback_candidate objects should be stored.
*/
hash_table * const tfeedback_candidates;
gl_shader_stage stage;
/**
* Pointer to the toplevel variable that is being traversed.
*/
ir_variable *toplevel_var;
/**
* Total number of varying floats that have been visited so far. This is
* used to determine the offset to each varying within the toplevel
* variable.
*/
unsigned varying_floats;
};
namespace linker {
void
populate_consumer_input_sets(void *mem_ctx, exec_list *ir,
hash_table *consumer_inputs,
hash_table *consumer_interface_inputs,
ir_variable *consumer_inputs_with_locations[VARYING_SLOT_TESS_MAX])
{
memset(consumer_inputs_with_locations,
0,
sizeof(consumer_inputs_with_locations[0]) * VARYING_SLOT_TESS_MAX);
foreach_in_list(ir_instruction, node, ir) {
ir_variable *const input_var = node->as_variable();
if (input_var != NULL && input_var->data.mode == ir_var_shader_in) {
/* All interface blocks should have been lowered by this point */
assert(!input_var->type->is_interface());
if (input_var->data.explicit_location) {
/* assign_varying_locations only cares about finding the
* ir_variable at the start of a contiguous location block.
*
* - For !producer, consumer_inputs_with_locations isn't used.
*
* - For !consumer, consumer_inputs_with_locations is empty.
*
* For consumer && producer, if you were trying to set some
* ir_variable to the middle of a location block on the other side
* of producer/consumer, cross_validate_outputs_to_inputs() should
* be link-erroring due to either type mismatch or location
* overlaps. If the variables do match up, then they've got a
* matching data.location and you only looked at
* consumer_inputs_with_locations[var->data.location], not any
* following entries for the array/structure.
*/
consumer_inputs_with_locations[input_var->data.location] =
input_var;
} else if (input_var->get_interface_type() != NULL) {
char *const iface_field_name =
ralloc_asprintf(mem_ctx, "%s.%s",
input_var->get_interface_type()->without_array()->name,
input_var->name);
_mesa_hash_table_insert(consumer_interface_inputs,
iface_field_name, input_var);
} else {
_mesa_hash_table_insert(consumer_inputs,
ralloc_strdup(mem_ctx, input_var->name),
input_var);
}
}
}
}
/**
* Find a variable from the consumer that "matches" the specified variable
*
* This function only finds inputs with names that match. There is no
* validation (here) that the types, etc. are compatible.
*/
ir_variable *
get_matching_input(void *mem_ctx,
const ir_variable *output_var,
hash_table *consumer_inputs,
hash_table *consumer_interface_inputs,
ir_variable *consumer_inputs_with_locations[VARYING_SLOT_TESS_MAX])
{
ir_variable *input_var;
if (output_var->data.explicit_location) {
input_var = consumer_inputs_with_locations[output_var->data.location];
} else if (output_var->get_interface_type() != NULL) {
char *const iface_field_name =
ralloc_asprintf(mem_ctx, "%s.%s",
output_var->get_interface_type()->without_array()->name,
output_var->name);
hash_entry *entry = _mesa_hash_table_search(consumer_interface_inputs, iface_field_name);
input_var = entry ? (ir_variable *) entry->data : NULL;
} else {
hash_entry *entry = _mesa_hash_table_search(consumer_inputs, output_var->name);
input_var = entry ? (ir_variable *) entry->data : NULL;
}
return (input_var == NULL || input_var->data.mode != ir_var_shader_in)
? NULL : input_var;
}
}
static int
io_variable_cmp(const void *_a, const void *_b)
{
const ir_variable *const a = *(const ir_variable **) _a;
const ir_variable *const b = *(const ir_variable **) _b;
if (a->data.explicit_location && b->data.explicit_location)
return b->data.location - a->data.location;
if (a->data.explicit_location && !b->data.explicit_location)
return 1;
if (!a->data.explicit_location && b->data.explicit_location)
return -1;
return -strcmp(a->name, b->name);
}
/**
* Sort the shader IO variables into canonical order
*/
static void
canonicalize_shader_io(exec_list *ir, enum ir_variable_mode io_mode)
{
ir_variable *var_table[MAX_PROGRAM_OUTPUTS * 4];
unsigned num_variables = 0;
foreach_in_list(ir_instruction, node, ir) {
ir_variable *const var = node->as_variable();
if (var == NULL || var->data.mode != io_mode)
continue;
/* If we have already encountered more I/O variables that could
* successfully link, bail.
*/
if (num_variables == ARRAY_SIZE(var_table))
return;
var_table[num_variables++] = var;
}
if (num_variables == 0)
return;
/* Sort the list in reverse order (io_variable_cmp handles this). Later
* we're going to push the variables on to the IR list as a stack, so we
* want the last variable (in canonical order) to be first in the list.
*/
qsort(var_table, num_variables, sizeof(var_table[0]), io_variable_cmp);
/* Remove the variable from it's current location in the IR, and put it at
* the front.
*/
for (unsigned i = 0; i < num_variables; i++) {
var_table[i]->remove();
ir->push_head(var_table[i]);
}
}
/**
* Generate a bitfield map of the explicit locations for shader varyings.
*
* Note: For Tessellation shaders we are sitting right on the limits of the
* 64 bit map. Per-vertex and per-patch both have separate location domains
* with a max of MAX_VARYING.
*/
static uint64_t
reserved_varying_slot(struct gl_linked_shader *stage,
ir_variable_mode io_mode)
{
assert(io_mode == ir_var_shader_in || io_mode == ir_var_shader_out);
/* Avoid an overflow of the returned value */
assert(MAX_VARYINGS_INCL_PATCH <= 64);
uint64_t slots = 0;
int var_slot;
if (!stage)
return slots;
foreach_in_list(ir_instruction, node, stage->ir) {
ir_variable *const var = node->as_variable();
if (var == NULL || var->data.mode != io_mode ||
!var->data.explicit_location ||
var->data.location < VARYING_SLOT_VAR0)
continue;
var_slot = var->data.location - VARYING_SLOT_VAR0;
unsigned num_elements = get_varying_type(var, stage->Stage)
->count_attribute_slots(io_mode == ir_var_shader_in &&
stage->Stage == MESA_SHADER_VERTEX);
for (unsigned i = 0; i < num_elements; i++) {
if (var_slot >= 0 && var_slot < MAX_VARYINGS_INCL_PATCH)
slots |= UINT64_C(1) << var_slot;
var_slot += 1;
}
}
return slots;
}
/**
* Assign locations for all variables that are produced in one pipeline stage
* (the "producer") and consumed in the next stage (the "consumer").
*
* Variables produced by the producer may also be consumed by transform
* feedback.
*
* \param num_tfeedback_decls is the number of declarations indicating
* variables that may be consumed by transform feedback.
*
* \param tfeedback_decls is a pointer to an array of tfeedback_decl objects
* representing the result of parsing the strings passed to
* glTransformFeedbackVaryings(). assign_location() will be called for
* each of these objects that matches one of the outputs of the
* producer.
*
* When num_tfeedback_decls is nonzero, it is permissible for the consumer to
* be NULL. In this case, varying locations are assigned solely based on the
* requirements of transform feedback.
*/
static bool
assign_varying_locations(struct gl_context *ctx,
void *mem_ctx,
struct gl_shader_program *prog,
gl_linked_shader *producer,
gl_linked_shader *consumer,
unsigned num_tfeedback_decls,
tfeedback_decl *tfeedback_decls,
const uint64_t reserved_slots)
{
/* Tessellation shaders treat inputs and outputs as shared memory and can
* access inputs and outputs of other invocations.
* Therefore, they can't be lowered to temps easily (and definitely not
* efficiently).
*/
bool unpackable_tess =
(consumer && consumer->Stage == MESA_SHADER_TESS_EVAL) ||
(consumer && consumer->Stage == MESA_SHADER_TESS_CTRL) ||
(producer && producer->Stage == MESA_SHADER_TESS_CTRL);
/* Transform feedback code assumes varying arrays are packed, so if the
* driver has disabled varying packing, make sure to at least enable
* packing required by transform feedback.
*/
bool xfb_enabled =
ctx->Extensions.EXT_transform_feedback && !unpackable_tess;
/* Disable packing on outward facing interfaces for SSO because in ES we
* need to retain the unpacked varying information for draw time
* validation.
*
* Packing is still enabled on individual arrays, structs, and matrices as
* these are required by the transform feedback code and it is still safe
* to do so. We also enable packing when a varying is only used for
* transform feedback and its not a SSO.
*/
bool disable_varying_packing =
ctx->Const.DisableVaryingPacking || unpackable_tess;
if (prog->SeparateShader && (producer == NULL || consumer == NULL))
disable_varying_packing = true;
varying_matches matches(disable_varying_packing, xfb_enabled,
ctx->Extensions.ARB_enhanced_layouts,
producer ? producer->Stage : MESA_SHADER_NONE,
consumer ? consumer->Stage : MESA_SHADER_NONE);
hash_table *tfeedback_candidates =
_mesa_hash_table_create(NULL, _mesa_key_hash_string,
_mesa_key_string_equal);
hash_table *consumer_inputs =
_mesa_hash_table_create(NULL, _mesa_key_hash_string,
_mesa_key_string_equal);
hash_table *consumer_interface_inputs =
_mesa_hash_table_create(NULL, _mesa_key_hash_string,
_mesa_key_string_equal);
ir_variable *consumer_inputs_with_locations[VARYING_SLOT_TESS_MAX] = {
NULL,
};
unsigned consumer_vertices = 0;
if (consumer && consumer->Stage == MESA_SHADER_GEOMETRY)
consumer_vertices = prog->Geom.VerticesIn;
/* Operate in a total of four passes.
*
* 1. Sort inputs / outputs into a canonical order. This is necessary so
* that inputs / outputs of separable shaders will be assigned
* predictable locations regardless of the order in which declarations
* appeared in the shader source.
*
* 2. Assign locations for any matching inputs and outputs.
*
* 3. Mark output variables in the producer that do not have locations as
* not being outputs. This lets the optimizer eliminate them.
*
* 4. Mark input variables in the consumer that do not have locations as
* not being inputs. This lets the optimizer eliminate them.
*/
if (consumer)
canonicalize_shader_io(consumer->ir, ir_var_shader_in);
if (producer)
canonicalize_shader_io(producer->ir, ir_var_shader_out);
if (consumer)
linker::populate_consumer_input_sets(mem_ctx, consumer->ir,
consumer_inputs,
consumer_interface_inputs,
consumer_inputs_with_locations);
if (producer) {
foreach_in_list(ir_instruction, node, producer->ir) {
ir_variable *const output_var = node->as_variable();
if (output_var == NULL || output_var->data.mode != ir_var_shader_out)
continue;
/* Only geometry shaders can use non-zero streams */
assert(output_var->data.stream == 0 ||
(output_var->data.stream < MAX_VERTEX_STREAMS &&
producer->Stage == MESA_SHADER_GEOMETRY));
if (num_tfeedback_decls > 0) {
tfeedback_candidate_generator g(mem_ctx, tfeedback_candidates, producer->Stage);
/* From OpenGL 4.6 (Core Profile) spec, section 11.1.2.1
* ("Vertex Shader Variables / Output Variables")
*
* "Each program object can specify a set of output variables from
* one shader to be recorded in transform feedback mode (see
* section 13.3). The variables that can be recorded are those
* emitted by the first active shader, in order, from the
* following list:
*
* * geometry shader
* * tessellation evaluation shader
* * tessellation control shader
* * vertex shader"
*
* But on OpenGL ES 3.2, section 11.1.2.1 ("Vertex Shader
* Variables / Output Variables") tessellation control shader is
* not included in the stages list.
*/
if (!prog->IsES || producer->Stage != MESA_SHADER_TESS_CTRL) {
g.process(output_var);
}
}
ir_variable *const input_var =
linker::get_matching_input(mem_ctx, output_var, consumer_inputs,
consumer_interface_inputs,
consumer_inputs_with_locations);
/* If a matching input variable was found, add this output (and the
* input) to the set. If this is a separable program and there is no
* consumer stage, add the output.
*
* Always add TCS outputs. They are shared by all invocations
* within a patch and can be used as shared memory.
*/
if (input_var || (prog->SeparateShader && consumer == NULL) ||
producer->Stage == MESA_SHADER_TESS_CTRL) {
matches.record(output_var, input_var);
}
/* Only stream 0 outputs can be consumed in the next stage */
if (input_var && output_var->data.stream != 0) {
linker_error(prog, "output %s is assigned to stream=%d but "
"is linked to an input, which requires stream=0",
output_var->name, output_var->data.stream);
return false;
}
}
} else {
/* If there's no producer stage, then this must be a separable program.
* For example, we may have a program that has just a fragment shader.
* Later this program will be used with some arbitrary vertex (or
* geometry) shader program. This means that locations must be assigned
* for all the inputs.
*/
foreach_in_list(ir_instruction, node, consumer->ir) {
ir_variable *const input_var = node->as_variable();
if (input_var && input_var->data.mode == ir_var_shader_in) {
matches.record(NULL, input_var);
}
}
}
for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
if (!tfeedback_decls[i].is_varying())
continue;
const tfeedback_candidate *matched_candidate
= tfeedback_decls[i].find_candidate(prog, tfeedback_candidates);
if (matched_candidate == NULL) {
_mesa_hash_table_destroy(tfeedback_candidates, NULL);
return false;
}
/* Mark xfb varyings as always active */
matched_candidate->toplevel_var->data.always_active_io = 1;
/* Mark any corresponding inputs as always active also. We must do this
* because we have a NIR pass that lowers vectors to scalars and another
* that removes unused varyings.
* We don't split varyings marked as always active because there is no
* point in doing so. This means we need to mark both sides of the
* interface as always active otherwise we will have a mismatch and
* start removing things we shouldn't.
*/
ir_variable *const input_var =
linker::get_matching_input(mem_ctx, matched_candidate->toplevel_var,
consumer_inputs,
consumer_interface_inputs,
consumer_inputs_with_locations);
if (input_var)
input_var->data.always_active_io = 1;
if (matched_candidate->toplevel_var->data.is_unmatched_generic_inout) {
matched_candidate->toplevel_var->data.is_xfb_only = 1;
matches.record(matched_candidate->toplevel_var, NULL);
}
}
_mesa_hash_table_destroy(consumer_inputs, NULL);
_mesa_hash_table_destroy(consumer_interface_inputs, NULL);
uint8_t components[MAX_VARYINGS_INCL_PATCH] = {0};
const unsigned slots_used = matches.assign_locations(
prog, components, reserved_slots);
matches.store_locations();
for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
if (tfeedback_decls[i].is_varying()) {
if (!tfeedback_decls[i].assign_location(ctx, prog)) {
_mesa_hash_table_destroy(tfeedback_candidates, NULL);
return false;
}
}
}
_mesa_hash_table_destroy(tfeedback_candidates, NULL);
if (consumer && producer) {
foreach_in_list(ir_instruction, node, consumer->ir) {
ir_variable *const var = node->as_variable();
if (var && var->data.mode == ir_var_shader_in &&
var->data.is_unmatched_generic_inout) {
if (!prog->IsES && prog->data->Version <= 120) {
/* On page 25 (page 31 of the PDF) of the GLSL 1.20 spec:
*
* Only those varying variables used (i.e. read) in
* the fragment shader executable must be written to
* by the vertex shader executable; declaring
* superfluous varying variables in a vertex shader is
* permissible.
*
* We interpret this text as meaning that the VS must
* write the variable for the FS to read it. See
* "glsl1-varying read but not written" in piglit.
*/
linker_error(prog, "%s shader varying %s not written "
"by %s shader\n.",
_mesa_shader_stage_to_string(consumer->Stage),
var->name,
_mesa_shader_stage_to_string(producer->Stage));
} else {
linker_warning(prog, "%s shader varying %s not written "
"by %s shader\n.",
_mesa_shader_stage_to_string(consumer->Stage),
var->name,
_mesa_shader_stage_to_string(producer->Stage));
}
}
}
/* Now that validation is done its safe to remove unused varyings. As
* we have both a producer and consumer its safe to remove unused
* varyings even if the program is a SSO because the stages are being
* linked together i.e. we have a multi-stage SSO.
*/
remove_unused_shader_inputs_and_outputs(false, producer,
ir_var_shader_out);
remove_unused_shader_inputs_and_outputs(false, consumer,
ir_var_shader_in);
}
if (producer) {
lower_packed_varyings(mem_ctx, slots_used, components, ir_var_shader_out,
0, producer, disable_varying_packing,
xfb_enabled);
}
if (consumer) {
lower_packed_varyings(mem_ctx, slots_used, components, ir_var_shader_in,
consumer_vertices, consumer,
disable_varying_packing, xfb_enabled);
}
return true;
}
static bool
check_against_output_limit(struct gl_context *ctx,
struct gl_shader_program *prog,
gl_linked_shader *producer,
unsigned num_explicit_locations)
{
unsigned output_vectors = num_explicit_locations;
foreach_in_list(ir_instruction, node, producer->ir) {
ir_variable *const var = node->as_variable();
if (var && !var->data.explicit_location &&
var->data.mode == ir_var_shader_out &&
var_counts_against_varying_limit(producer->Stage, var)) {
/* outputs for fragment shader can't be doubles */
output_vectors += var->type->count_attribute_slots(false);
}
}
assert(producer->Stage != MESA_SHADER_FRAGMENT);
unsigned max_output_components =
ctx->Const.Program[producer->Stage].MaxOutputComponents;
const unsigned output_components = output_vectors * 4;
if (output_components > max_output_components) {
if (ctx->API == API_OPENGLES2 || prog->IsES)
linker_error(prog, "%s shader uses too many output vectors "
"(%u > %u)\n",
_mesa_shader_stage_to_string(producer->Stage),
output_vectors,
max_output_components / 4);
else
linker_error(prog, "%s shader uses too many output components "
"(%u > %u)\n",
_mesa_shader_stage_to_string(producer->Stage),
output_components,
max_output_components);
return false;
}
return true;
}
static bool
check_against_input_limit(struct gl_context *ctx,
struct gl_shader_program *prog,
gl_linked_shader *consumer,
unsigned num_explicit_locations)
{
unsigned input_vectors = num_explicit_locations;
foreach_in_list(ir_instruction, node, consumer->ir) {
ir_variable *const var = node->as_variable();
if (var && !var->data.explicit_location &&
var->data.mode == ir_var_shader_in &&
var_counts_against_varying_limit(consumer->Stage, var)) {
/* vertex inputs aren't varying counted */
input_vectors += var->type->count_attribute_slots(false);
}
}
assert(consumer->Stage != MESA_SHADER_VERTEX);
unsigned max_input_components =
ctx->Const.Program[consumer->Stage].MaxInputComponents;
const unsigned input_components = input_vectors * 4;
if (input_components > max_input_components) {
if (ctx->API == API_OPENGLES2 || prog->IsES)
linker_error(prog, "%s shader uses too many input vectors "
"(%u > %u)\n",
_mesa_shader_stage_to_string(consumer->Stage),
input_vectors,
max_input_components / 4);
else
linker_error(prog, "%s shader uses too many input components "
"(%u > %u)\n",
_mesa_shader_stage_to_string(consumer->Stage),
input_components,
max_input_components);
return false;
}
return true;
}
bool
link_varyings(struct gl_shader_program *prog, unsigned first, unsigned last,
struct gl_context *ctx, void *mem_ctx)
{
bool has_xfb_qualifiers = false;
unsigned num_tfeedback_decls = 0;
char **varying_names = NULL;
tfeedback_decl *tfeedback_decls = NULL;
/* From the ARB_enhanced_layouts spec:
*
* "If the shader used to record output variables for transform feedback
* varyings uses the "xfb_buffer", "xfb_offset", or "xfb_stride" layout
* qualifiers, the values specified by TransformFeedbackVaryings are
* ignored, and the set of variables captured for transform feedback is
* instead derived from the specified layout qualifiers."
*/
for (int i = MESA_SHADER_FRAGMENT - 1; i >= 0; i--) {
/* Find last stage before fragment shader */
if (prog->_LinkedShaders[i]) {
has_xfb_qualifiers =
process_xfb_layout_qualifiers(mem_ctx, prog->_LinkedShaders[i],
prog, &num_tfeedback_decls,
&varying_names);
break;
}
}
if (!has_xfb_qualifiers) {
num_tfeedback_decls = prog->TransformFeedback.NumVarying;
varying_names = prog->TransformFeedback.VaryingNames;
}
if (num_tfeedback_decls != 0) {
/* From GL_EXT_transform_feedback:
* A program will fail to link if:
*
* * the <count> specified by TransformFeedbackVaryingsEXT is
* non-zero, but the program object has no vertex or geometry
* shader;
*/
if (first >= MESA_SHADER_FRAGMENT) {
linker_error(prog, "Transform feedback varyings specified, but "
"no vertex, tessellation, or geometry shader is "
"present.\n");
return false;
}
tfeedback_decls = rzalloc_array(mem_ctx, tfeedback_decl,
num_tfeedback_decls);
if (!parse_tfeedback_decls(ctx, prog, mem_ctx, num_tfeedback_decls,
varying_names, tfeedback_decls))
return false;
}
/* If there is no fragment shader we need to set transform feedback.
*
* For SSO we also need to assign output locations. We assign them here
* because we need to do it for both single stage programs and multi stage
* programs.
*/
if (last < MESA_SHADER_FRAGMENT &&
(num_tfeedback_decls != 0 || prog->SeparateShader)) {
const uint64_t reserved_out_slots =
reserved_varying_slot(prog->_LinkedShaders[last], ir_var_shader_out);
if (!assign_varying_locations(ctx, mem_ctx, prog,
prog->_LinkedShaders[last], NULL,
num_tfeedback_decls, tfeedback_decls,
reserved_out_slots))
return false;
}
if (last <= MESA_SHADER_FRAGMENT) {
/* Remove unused varyings from the first/last stage unless SSO */
remove_unused_shader_inputs_and_outputs(prog->SeparateShader,
prog->_LinkedShaders[first],
ir_var_shader_in);
remove_unused_shader_inputs_and_outputs(prog->SeparateShader,
prog->_LinkedShaders[last],
ir_var_shader_out);
/* If the program is made up of only a single stage */
if (first == last) {
gl_linked_shader *const sh = prog->_LinkedShaders[last];
do_dead_builtin_varyings(ctx, NULL, sh, 0, NULL);
do_dead_builtin_varyings(ctx, sh, NULL, num_tfeedback_decls,
tfeedback_decls);
if (prog->SeparateShader) {
const uint64_t reserved_slots =
reserved_varying_slot(sh, ir_var_shader_in);
/* Assign input locations for SSO, output locations are already
* assigned.
*/
if (!assign_varying_locations(ctx, mem_ctx, prog,
NULL /* producer */,
sh /* consumer */,
0 /* num_tfeedback_decls */,
NULL /* tfeedback_decls */,
reserved_slots))
return false;
}
} else {
/* Linking the stages in the opposite order (from fragment to vertex)
* ensures that inter-shader outputs written to in an earlier stage
* are eliminated if they are (transitively) not used in a later
* stage.
*/
int next = last;
for (int i = next - 1; i >= 0; i--) {
if (prog->_LinkedShaders[i] == NULL && i != 0)
continue;
gl_linked_shader *const sh_i = prog->_LinkedShaders[i];
gl_linked_shader *const sh_next = prog->_LinkedShaders[next];
const uint64_t reserved_out_slots =
reserved_varying_slot(sh_i, ir_var_shader_out);
const uint64_t reserved_in_slots =
reserved_varying_slot(sh_next, ir_var_shader_in);
do_dead_builtin_varyings(ctx, sh_i, sh_next,
next == MESA_SHADER_FRAGMENT ? num_tfeedback_decls : 0,
tfeedback_decls);
if (!assign_varying_locations(ctx, mem_ctx, prog, sh_i, sh_next,
next == MESA_SHADER_FRAGMENT ? num_tfeedback_decls : 0,
tfeedback_decls,
reserved_out_slots | reserved_in_slots))
return false;
/* This must be done after all dead varyings are eliminated. */
if (sh_i != NULL) {
unsigned slots_used = util_bitcount64(reserved_out_slots);
if (!check_against_output_limit(ctx, prog, sh_i, slots_used)) {
return false;
}
}
unsigned slots_used = util_bitcount64(reserved_in_slots);
if (!check_against_input_limit(ctx, prog, sh_next, slots_used))
return false;
next = i;
}
}
}
if (!store_tfeedback_info(ctx, prog, num_tfeedback_decls, tfeedback_decls,
has_xfb_qualifiers))
return false;
return true;
}