/*
* 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/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 "program/hash_table.h"
#include "program.h"
/**
* Validate that outputs from one stage match inputs of another
*/
bool
cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
gl_shader *producer, gl_shader *consumer)
{
glsl_symbol_table parameters;
const char *const producer_stage =
_mesa_glsl_shader_target_name(producer->Type);
const char *const consumer_stage =
_mesa_glsl_shader_target_name(consumer->Type);
/* Find all shader outputs in the "producer" stage.
*/
foreach_list(node, producer->ir) {
ir_variable *const var = ((ir_instruction *) node)->as_variable();
if ((var == NULL) || (var->mode != ir_var_shader_out))
continue;
parameters.add_variable(var);
}
/* 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.
*/
foreach_list(node, consumer->ir) {
ir_variable *const input = ((ir_instruction *) node)->as_variable();
if ((input == NULL) || (input->mode != ir_var_shader_in))
continue;
ir_variable *const output = parameters.get_variable(input->name);
if (output != NULL) {
/* Check that the types match between stages.
*/
if (input->type != 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()
|| (strncmp("gl_", output->name, 3) != 0)) {
linker_error(prog,
"%s shader output `%s' declared as type `%s', "
"but %s shader input declared as type `%s'\n",
producer_stage, output->name,
output->type->name,
consumer_stage, input->type->name);
return false;
}
}
/* Check that all of the qualifiers match between stages.
*/
if (input->centroid != output->centroid) {
linker_error(prog,
"%s shader output `%s' %s centroid qualifier, "
"but %s shader input %s centroid qualifier\n",
producer_stage,
output->name,
(output->centroid) ? "has" : "lacks",
consumer_stage,
(input->centroid) ? "has" : "lacks");
return false;
}
if (input->invariant != output->invariant) {
linker_error(prog,
"%s shader output `%s' %s invariant qualifier, "
"but %s shader input %s invariant qualifier\n",
producer_stage,
output->name,
(output->invariant) ? "has" : "lacks",
consumer_stage,
(input->invariant) ? "has" : "lacks");
return false;
}
if (input->interpolation != output->interpolation) {
linker_error(prog,
"%s shader output `%s' specifies %s "
"interpolation qualifier, "
"but %s shader input specifies %s "
"interpolation qualifier\n",
producer_stage,
output->name,
output->interpolation_string(),
consumer_stage,
input->interpolation_string());
return false;
}
}
}
return true;
}
/**
* 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, struct gl_shader_program *prog,
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->is_clip_distance_mesa = false;
this->skip_components = 0;
this->next_buffer_separator = false;
this->matched_candidate = NULL;
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 (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->ShaderCompilerOptions[MESA_SHADER_VERTEX].LowerClipDistance &&
strcmp(this->var_name, "gl_ClipDistance") == 0) {
this->is_clip_distance_mesa = true;
}
}
/**
* 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 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->location * 4
+ this->matched_candidate->toplevel_var->location_frac
+ this->matched_candidate->offset;
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 = this->is_clip_distance_mesa ?
prog->Vert.ClipDistanceArraySize :
this->matched_candidate->type->array_size();
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->is_clip_distance_mesa ?
1 : vector_elements * matrix_cols;
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->is_clip_distance_mesa)
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;
}
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, const unsigned max_outputs) const
{
assert(!this->next_buffer_separator);
/* Handle gl_SkipComponents. */
if (this->skip_components) {
info->BufferStride[buffer] += this->skip_components;
return true;
}
/* 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.
*/
if (prog->TransformFeedback.BufferMode == GL_INTERLEAVED_ATTRIBS &&
info->BufferStride[buffer] + this->num_components() >
ctx->Const.MaxTransformFeedbackInterleavedComponents) {
linker_error(prog, "The MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS "
"limit has been exceeded.");
return false;
}
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 < max_outputs);
info->Outputs[info->NumOutputs].ComponentOffset = location_frac;
info->Outputs[info->NumOutputs].OutputRegister = location;
info->Outputs[info->NumOutputs].NumComponents = output_size;
info->Outputs[info->NumOutputs].OutputBuffer = buffer;
info->Outputs[info->NumOutputs].DstOffset = info->BufferStride[buffer];
++info->NumOutputs;
info->BufferStride[buffer] += output_size;
num_components -= output_size;
location++;
location_frac = 0;
}
info->Varyings[info->NumVarying].Name = ralloc_strdup(prog, this->orig_name);
info->Varyings[info->NumVarying].Type = this->type;
info->Varyings[info->NumVarying].Size = this->size;
info->NumVarying++;
return true;
}
const tfeedback_candidate *
tfeedback_decl::find_candidate(gl_shader_program *prog,
hash_table *tfeedback_candidates)
{
const char *name = this->is_clip_distance_mesa
? "gl_ClipDistanceMESA" : this->var_name;
this->matched_candidate = (const tfeedback_candidate *)
hash_table_find(tfeedback_candidates, name);
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.
*/
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, prog, 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())
continue;
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;
}
/**
* Store transform feedback location assignments into
* prog->LinkedTransformFeedback based on the data stored in tfeedback_decls.
*
* If an error occurs, the error is reported through linker_error() and false
* is returned.
*/
bool
store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog,
unsigned num_tfeedback_decls,
tfeedback_decl *tfeedback_decls)
{
bool separate_attribs_mode =
prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS;
ralloc_free(prog->LinkedTransformFeedback.Varyings);
ralloc_free(prog->LinkedTransformFeedback.Outputs);
memset(&prog->LinkedTransformFeedback, 0,
sizeof(prog->LinkedTransformFeedback));
prog->LinkedTransformFeedback.Varyings =
rzalloc_array(prog,
struct gl_transform_feedback_varying_info,
num_tfeedback_decls);
unsigned num_outputs = 0;
for (unsigned i = 0; i < num_tfeedback_decls; ++i)
num_outputs += tfeedback_decls[i].get_num_outputs();
prog->LinkedTransformFeedback.Outputs =
rzalloc_array(prog,
struct gl_transform_feedback_output,
num_outputs);
unsigned num_buffers = 0;
if (separate_attribs_mode) {
/* GL_SEPARATE_ATTRIBS */
for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
if (!tfeedback_decls[i].store(ctx, prog, &prog->LinkedTransformFeedback,
num_buffers, num_outputs))
return false;
num_buffers++;
}
}
else {
/* GL_INVERLEAVED_ATTRIBS */
for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
if (tfeedback_decls[i].is_next_buffer_separator()) {
num_buffers++;
continue;
}
if (!tfeedback_decls[i].store(ctx, prog,
&prog->LinkedTransformFeedback,
num_buffers, num_outputs))
return false;
}
num_buffers++;
}
assert(prog->LinkedTransformFeedback.NumOutputs == num_outputs);
prog->LinkedTransformFeedback.NumBuffers = num_buffers;
return true;
}
/**
* 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 consumer_is_fs);
~varying_matches();
void record(ir_variable *producer_var, ir_variable *consumer_var);
unsigned assign_locations();
void store_locations(unsigned producer_base, unsigned consumer_base) const;
private:
/**
* 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.
*/
const bool disable_varying_packing;
/**
* 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(ir_variable *var);
static packing_order_enum compute_packing_order(ir_variable *var);
static int match_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;
const bool consumer_is_fs;
};
varying_matches::varying_matches(bool disable_varying_packing,
bool consumer_is_fs)
: disable_varying_packing(disable_varying_packing),
consumer_is_fs(consumer_is_fs)
{
/* 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);
}
/**
* 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)
{
if (!producer_var->is_unmatched_generic_inout) {
/* 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;
}
if ((consumer_var == NULL && producer_var->type->contains_integer()) ||
!consumer_is_fs) {
/* 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.
*
* 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.
*/
producer_var->centroid = false;
producer_var->interpolation = INTERP_QUALIFIER_FLAT;
if (consumer_var) {
consumer_var->centroid = false;
consumer_var->interpolation = INTERP_QUALIFIER_FLAT;
}
}
if (this->num_matches == this->matches_capacity) {
this->matches_capacity *= 2;
this->matches = (match *)
realloc(this->matches,
sizeof(*this->matches) * this->matches_capacity);
}
this->matches[this->num_matches].packing_class
= this->compute_packing_class(producer_var);
this->matches[this->num_matches].packing_order
= this->compute_packing_order(producer_var);
if (this->disable_varying_packing) {
unsigned slots = producer_var->type->is_array()
? (producer_var->type->length
* producer_var->type->fields.array->matrix_columns)
: producer_var->type->matrix_columns;
this->matches[this->num_matches].num_components = 4 * slots;
} else {
this->matches[this->num_matches].num_components
= producer_var->type->component_slots();
}
this->matches[this->num_matches].producer_var = producer_var;
this->matches[this->num_matches].consumer_var = consumer_var;
this->num_matches++;
producer_var->is_unmatched_generic_inout = 0;
if (consumer_var)
consumer_var->is_unmatched_generic_inout = 0;
}
/**
* Choose locations for all of the variable matches that were previously
* passed to varying_matches::record().
*/
unsigned
varying_matches::assign_locations()
{
/* 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);
unsigned generic_location = 0;
for (unsigned i = 0; i < this->num_matches; i++) {
/* 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.
*/
if (i > 0 &&
this->matches[i - 1].packing_class
!= this->matches[i].packing_class) {
generic_location = ALIGN(generic_location, 4);
}
this->matches[i].generic_location = generic_location;
generic_location += this->matches[i].num_components;
}
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(unsigned producer_base,
unsigned consumer_base) const
{
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;
producer_var->location = producer_base + slot;
producer_var->location_frac = offset;
if (consumer_var) {
assert(consumer_var->location == -1);
consumer_var->location = consumer_base + slot;
consumer_var->location_frac = offset;
}
}
}
/**
* 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(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.
*/
unsigned packing_class = var->centroid ? 1 : 0;
packing_class *= 4;
packing_class += var->interpolation;
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(ir_variable *var)
{
const glsl_type *element_type = var->type;
while (element_type->base_type == GLSL_TYPE_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;
}
/**
* 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
is_varying_var(GLenum shaderType, const ir_variable *var)
{
/* Only fragment shaders will take a varying variable as an input */
if (shaderType == GL_FRAGMENT_SHADER &&
var->mode == ir_var_shader_in) {
switch (var->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)
: mem_ctx(mem_ctx),
tfeedback_candidates(tfeedback_candidates),
toplevel_var(NULL),
varying_floats(0)
{
}
void process(ir_variable *var)
{
this->toplevel_var = var;
this->varying_floats = 0;
if (var->is_interface_instance())
program_resource_visitor::process(var->interface_type,
var->interface_type->name);
else
program_resource_visitor::process(var);
}
private:
virtual void visit_field(const glsl_type *type, const char *name,
bool row_major)
{
assert(!type->is_record());
assert(!(type->is_array() && type->fields.array->is_record()));
assert(!type->is_interface());
assert(!(type->is_array() && type->fields.array->is_interface()));
(void) row_major;
tfeedback_candidate *candidate
= rzalloc(this->mem_ctx, tfeedback_candidate);
candidate->toplevel_var = this->toplevel_var;
candidate->type = type;
candidate->offset = this->varying_floats;
hash_table_insert(this->tfeedback_candidates, candidate,
ralloc_strdup(this->mem_ctx, name));
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;
/**
* 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;
};
/**
* 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.
*/
bool
assign_varying_locations(struct gl_context *ctx,
void *mem_ctx,
struct gl_shader_program *prog,
gl_shader *producer, gl_shader *consumer,
unsigned num_tfeedback_decls,
tfeedback_decl *tfeedback_decls)
{
const unsigned producer_base = VARYING_SLOT_VAR0;
const unsigned consumer_base = VARYING_SLOT_VAR0;
varying_matches matches(ctx->Const.DisableVaryingPacking,
consumer && consumer->Type == GL_FRAGMENT_SHADER);
hash_table *tfeedback_candidates
= hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare);
hash_table *consumer_inputs
= hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare);
hash_table *consumer_interface_inputs
= hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare);
/* Operate in a total of three passes.
*
* 1. Assign locations for any matching inputs and outputs.
*
* 2. Mark output variables in the producer that do not have locations as
* not being outputs. This lets the optimizer eliminate them.
*
* 3. Mark input variables in the consumer that do not have locations as
* not being inputs. This lets the optimizer eliminate them.
*/
if (consumer) {
foreach_list(node, consumer->ir) {
ir_variable *const input_var =
((ir_instruction *) node)->as_variable();
if ((input_var != NULL) && (input_var->mode == ir_var_shader_in)) {
if (input_var->interface_type != NULL) {
char *const iface_field_name =
ralloc_asprintf(mem_ctx, "%s.%s",
input_var->interface_type->name,
input_var->name);
hash_table_insert(consumer_interface_inputs, input_var,
iface_field_name);
} else {
hash_table_insert(consumer_inputs, input_var,
ralloc_strdup(mem_ctx, input_var->name));
}
}
}
}
foreach_list(node, producer->ir) {
ir_variable *const output_var = ((ir_instruction *) node)->as_variable();
if ((output_var == NULL) || (output_var->mode != ir_var_shader_out))
continue;
tfeedback_candidate_generator g(mem_ctx, tfeedback_candidates);
g.process(output_var);
ir_variable *input_var;
if (output_var->interface_type != NULL) {
char *const iface_field_name =
ralloc_asprintf(mem_ctx, "%s.%s",
output_var->interface_type->name,
output_var->name);
input_var =
(ir_variable *) hash_table_find(consumer_interface_inputs,
iface_field_name);
} else {
input_var =
(ir_variable *) hash_table_find(consumer_inputs, output_var->name);
}
if (input_var && input_var->mode != ir_var_shader_in)
input_var = NULL;
if (input_var) {
matches.record(output_var, 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) {
hash_table_dtor(tfeedback_candidates);
hash_table_dtor(consumer_inputs);
hash_table_dtor(consumer_interface_inputs);
return false;
}
if (matched_candidate->toplevel_var->is_unmatched_generic_inout)
matches.record(matched_candidate->toplevel_var, NULL);
}
const unsigned slots_used = matches.assign_locations();
matches.store_locations(producer_base, consumer_base);
for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
if (!tfeedback_decls[i].is_varying())
continue;
if (!tfeedback_decls[i].assign_location(ctx, prog)) {
hash_table_dtor(tfeedback_candidates);
hash_table_dtor(consumer_inputs);
hash_table_dtor(consumer_interface_inputs);
return false;
}
}
hash_table_dtor(tfeedback_candidates);
hash_table_dtor(consumer_inputs);
hash_table_dtor(consumer_interface_inputs);
if (ctx->Const.DisableVaryingPacking) {
/* Transform feedback code assumes varyings are packed, so if the driver
* has disabled varying packing, make sure it does not support transform
* feedback.
*/
assert(!ctx->Extensions.EXT_transform_feedback);
} else {
lower_packed_varyings(mem_ctx, producer_base, slots_used,
ir_var_shader_out, producer);
if (consumer) {
lower_packed_varyings(mem_ctx, consumer_base, slots_used,
ir_var_shader_in, consumer);
}
}
if (consumer) {
foreach_list(node, consumer->ir) {
ir_variable *const var = ((ir_instruction *) node)->as_variable();
if (var && var->mode == ir_var_shader_in &&
var->is_unmatched_generic_inout) {
if (prog->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_glsl_shader_target_name(consumer->Type),
var->name,
_mesa_glsl_shader_target_name(producer->Type));
}
/* An 'in' variable is only really a shader input if its
* value is written by the previous stage.
*/
var->mode = ir_var_auto;
}
}
}
return true;
}
bool
check_against_varying_limit(struct gl_context *ctx,
struct gl_shader_program *prog,
gl_shader *consumer)
{
unsigned varying_vectors = 0;
foreach_list(node, consumer->ir) {
ir_variable *const var = ((ir_instruction *) node)->as_variable();
if (var && var->mode == ir_var_shader_in &&
is_varying_var(consumer->Type, var)) {
/* The packing rules used for vertex shader inputs are also
* used for fragment shader inputs.
*/
varying_vectors += count_attribute_slots(var->type);
}
}
if (ctx->API == API_OPENGLES2 || prog->IsES) {
if (varying_vectors > ctx->Const.MaxVarying) {
linker_error(prog, "shader uses too many varying vectors "
"(%u > %u)\n",
varying_vectors, ctx->Const.MaxVarying);
return false;
}
} else {
const unsigned float_components = varying_vectors * 4;
if (float_components > ctx->Const.MaxVarying * 4) {
linker_error(prog, "shader uses too many varying components "
"(%u > %u)\n",
float_components, ctx->Const.MaxVarying * 4);
return false;
}
}
return true;
}