From: Paul Berry Date: Tue, 4 Dec 2012 23:55:59 +0000 (-0800) Subject: glsl/linker: Subdivide the first phase of varying assignment. X-Git-Url: https://git.libre-soc.org/?a=commitdiff_plain;h=eb989e37cb7ed2e3268959bdd869dc305177e468;p=mesa.git glsl/linker: Subdivide the first phase of varying assignment. This patch further subdivides the loop that assigns varying locations into two phases: one phase to match up the varyings between shader stages, and one phase to assign them varying locations. In between the two phases the matched varyings are stored in a new data structure called varying_matches. This will free us to be able to assign varying locations in any order, which will pave the way for packing varyings. Note that the new varying_matches::assign_locations() function returns the number of varying slots that were used; this return value will be used in a future patch. Reviewed-by: Eric Anholt --- diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp index e4d31d79d69..439548ee8d6 100644 --- a/src/glsl/linker.cpp +++ b/src/glsl/linker.cpp @@ -1961,58 +1961,167 @@ parse_tfeedback_decls(struct gl_context *ctx, struct gl_shader_program *prog, /** - * Assign a location for a variable that is produced in one pipeline stage - * (the "producer") and consumed in the next stage (the "consumer"). - * - * \param input_var is the input variable declaration in the consumer. - * - * \param output_var is the output variable declaration in the producer. - * - * \param input_index is the counter that keeps track of assigned input - * locations in the consumer. - * - * \param output_index is the counter that keeps track of assigned output - * locations in the producer. + * 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(); + ~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: + /** + * Structure recording the relationship between a single producer output + * and a single consumer input. + */ + struct match { + /** + * 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 VERT_RESULT_VAR0 or FRAG_ATTRIB_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; +}; + + +varying_matches::varying_matches() +{ + /* 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 input_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). + * 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 the variable has already been assigned a location, this function has no - * effect. + * 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. */ void -assign_varying_location(ir_variable *input_var, ir_variable *output_var, - unsigned *input_index, unsigned *output_index) +varying_matches::record(ir_variable *producer_var, ir_variable *consumer_var) { - if (!output_var->is_unmatched_generic_inout) { - /* Location already assigned. */ + 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 (input_var) { - assert(input_var->location == -1); - input_var->location = *input_index; - input_var->is_unmatched_generic_inout = 0; + 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].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; +} - output_var->location = *output_index; - output_var->is_unmatched_generic_inout = 0; - /* FINISHME: Support for "varying" records in GLSL 1.50. */ - assert(!output_var->type->is_record()); +/** + * Choose locations for all of the variable matches that were previously + * passed to varying_matches::record(). + */ +unsigned +varying_matches::assign_locations() +{ + unsigned generic_location = 0; - if (output_var->type->is_array()) { - const unsigned slots = output_var->type->length - * output_var->type->fields.array->matrix_columns; + for (unsigned i = 0; i < this->num_matches; i++) { + this->matches[i].generic_location = generic_location; - *output_index += slots; - *input_index += slots; - } else { - const unsigned slots = output_var->type->matrix_columns; + ir_variable *producer_var = this->matches[i].producer_var; + + if (producer_var->type->is_array()) { + const unsigned slots = producer_var->type->length + * producer_var->type->fields.array->matrix_columns; + + generic_location += 4 * slots; + } else { + const unsigned slots = producer_var->type->matrix_columns; - *output_index += slots; - *input_index += slots; + generic_location += 4 * slots; + } + } + + 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; + } } } @@ -2070,8 +2179,9 @@ assign_varying_locations(struct gl_context *ctx, tfeedback_decl *tfeedback_decls) { /* FINISHME: Set dynamically when geometry shader support is added. */ - unsigned output_index = VERT_RESULT_VAR0; - unsigned input_index = FRAG_ATTRIB_VAR0; + const unsigned producer_base = VERT_RESULT_VAR0; + const unsigned consumer_base = FRAG_ATTRIB_VAR0; + varying_matches matches; /* Operate in a total of three passes. * @@ -2097,8 +2207,7 @@ assign_varying_locations(struct gl_context *ctx, input_var = NULL; if (input_var) { - assign_varying_location(input_var, output_var, &input_index, - &output_index); + matches.record(output_var, input_var); } } @@ -2113,9 +2222,19 @@ assign_varying_locations(struct gl_context *ctx, return false; if (output_var->is_unmatched_generic_inout) { - assign_varying_location(NULL, output_var, &input_index, - &output_index); + matches.record(output_var, NULL); } + } + + 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; + + ir_variable *output_var + = tfeedback_decls[i].find_output_var(prog, producer); if (!tfeedback_decls[i].assign_location(ctx, prog, output_var)) return false;