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Diffstat (limited to 'src/glsl/link_varyings.cpp')
| -rw-r--r-- | src/glsl/link_varyings.cpp | 1043 |
1 files changed, 1043 insertions, 0 deletions
diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp new file mode 100644 index 00000000000..b9c3f5d434d --- /dev/null +++ b/src/glsl/link_varyings.cpp @@ -0,0 +1,1043 @@ +/* + * 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 "ir_optimization.h" +#include "linker.h" +#include "link_varyings.h" +#include "main/macros.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; + /* FINISHME: Figure these out dynamically. */ + const char *const producer_stage = "vertex"; + const char *const consumer_stage = "fragment"; + + /* Find all shader outputs in the "producer" stage. + */ + foreach_list(node, producer->ir) { + ir_variable *const var = ((ir_instruction *) node)->as_variable(); + + /* FINISHME: For geometry shaders, this should also look for inout + * FINISHME: variables. + */ + if ((var == NULL) || (var->mode != ir_var_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(); + + /* FINISHME: For geometry shaders, this should also look for inout + * FINISHME: variables. + */ + if ((input == NULL) || (input->mode != ir_var_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 there is a parse error, the error is + * reported using linker_error(), and false is returned. + */ +bool +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; + + if (ctx->Extensions.ARB_transform_feedback3) { + /* Parse gl_NextBuffer. */ + if (strcmp(input, "gl_NextBuffer") == 0) { + this->next_buffer_separator = true; + return true; + } + + /* 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 true; + } + + /* Parse a declaration. */ + const char *bracket = strrchr(input, '['); + + if (bracket) { + this->var_name = ralloc_strndup(mem_ctx, input, bracket - input); + if (sscanf(bracket, "[%u]", &this->array_subscript) != 1) { + linker_error(prog, "Cannot parse transform feedback varying %s", input); + return false; + } + this->is_subscripted = true; + } else { + this->var_name = ralloc_strdup(mem_ctx, input); + 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; + } + + return 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 location + * assignment in output_var. + * + * 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, + ir_variable *output_var) +{ + assert(this->is_varying()); + + if (output_var->type->is_array()) { + /* Array variable */ + const unsigned matrix_cols = + output_var->type->fields.array->matrix_columns; + const unsigned vector_elements = + output_var->type->fields.array->vector_elements; + unsigned actual_array_size = this->is_clip_distance_mesa ? + prog->Vert.ClipDistanceArraySize : output_var->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; + } + if (this->is_clip_distance_mesa) { + this->location = + output_var->location + this->array_subscript / 4; + this->location_frac = this->array_subscript % 4; + } else { + unsigned fine_location + = output_var->location * 4 + output_var->location_frac; + unsigned array_elem_size = vector_elements * matrix_cols; + fine_location += array_elem_size * this->array_subscript; + this->location = fine_location / 4; + this->location_frac = fine_location % 4; + } + this->size = 1; + } else { + this->location = output_var->location; + this->location_frac = output_var->location_frac; + 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 = output_var->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->location = output_var->location; + this->location_frac = output_var->location_frac; + this->size = 1; + this->vector_elements = output_var->type->vector_elements; + this->matrix_columns = output_var->type->matrix_columns; + this->type = output_var->type->gl_type; + } + + /* 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; +} + + +ir_variable * +tfeedback_decl::find_output_var(gl_shader_program *prog, + gl_shader *producer) const +{ + const char *name = this->is_clip_distance_mesa + ? "gl_ClipDistanceMESA" : this->var_name; + ir_variable *var = producer->symbols->get_variable(name); + if (var && var->mode == ir_var_out) + return var; + + /* 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 NULL; +} + + +/** + * 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) { + if (!decls[i].init(ctx, prog, mem_ctx, varying_names[i])) + return false; + + 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); + ~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 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(bool disable_varying_packing) + : disable_varying_packing(disable_varying_packing) +{ + /* 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. + */ +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 (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) +{ + /* In this initial implementation we conservatively assume that variables + * can only be packed if their base type (float/int/uint/bool) matches and + * their interpolation and centroid qualifiers match. + * + * TODO: relax these restrictions when the driver back-end permits. + */ + unsigned packing_class = var->centroid ? 1 : 0; + packing_class *= 4; + packing_class += var->interpolation; + packing_class *= GLSL_TYPE_ERROR; + packing_class += var->type->get_scalar_type()->base_type; + 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; + + /* FINISHME: Support for "varying" records in GLSL 1.50. */ + while (element_type->base_type == GLSL_TYPE_ARRAY) { + element_type = element_type->fields.array; + } + + switch (element_type->vector_elements) { + case 1: return PACKING_ORDER_SCALAR; + case 2: return PACKING_ORDER_VEC2; + case 3: return PACKING_ORDER_VEC3; + case 4: 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_in) { + switch (var->location) { + case FRAG_ATTRIB_WPOS: + case FRAG_ATTRIB_FACE: + case FRAG_ATTRIB_PNTC: + return false; + default: + return true; + } + } + return false; +} + + +/** + * 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) +{ + /* FINISHME: Set dynamically when geometry shader support is added. */ + const unsigned producer_base = VERT_RESULT_VAR0; + const unsigned consumer_base = FRAG_ATTRIB_VAR0; + varying_matches matches(ctx->Const.DisableVaryingPacking); + + /* 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. + */ + + foreach_list(node, producer->ir) { + ir_variable *const output_var = ((ir_instruction *) node)->as_variable(); + + if ((output_var == NULL) || (output_var->mode != ir_var_out)) + continue; + + ir_variable *input_var = + consumer ? consumer->symbols->get_variable(output_var->name) : NULL; + + if (input_var && input_var->mode != ir_var_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; + + ir_variable *output_var + = tfeedback_decls[i].find_output_var(prog, producer); + + if (output_var == NULL) + return false; + + if (output_var->is_unmatched_generic_inout) { + matches.record(output_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; + + ir_variable *output_var + = tfeedback_decls[i].find_output_var(prog, producer); + + if (!tfeedback_decls[i].assign_location(ctx, prog, output_var)) + return false; + } + + 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_out, + producer); + if (consumer) { + lower_packed_varyings(mem_ctx, consumer_base, slots_used, ir_var_in, + consumer); + } + } + + unsigned varying_vectors = 0; + + if (consumer) { + foreach_list(node, consumer->ir) { + ir_variable *const var = ((ir_instruction *) node)->as_variable(); + + if ((var == NULL) || (var->mode != ir_var_in)) + continue; + + if (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, "fragment shader varying %s not written " + "by vertex shader\n.", var->name); + } + + /* An 'in' variable is only really a shader input if its + * value is written by the previous stage. + */ + var->mode = ir_var_auto; + } else if (is_varying_var(consumer->Type, var)) { + /* The packing rules are 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) { + if (ctx->Const.GLSLSkipStrictMaxVaryingLimitCheck) { + linker_warning(prog, "shader uses too many varying vectors " + "(%u > %u), but the driver will try to optimize " + "them out; this is non-portable out-of-spec " + "behavior\n", + varying_vectors, ctx->Const.MaxVarying); + } else { + 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) { + if (ctx->Const.GLSLSkipStrictMaxVaryingLimitCheck) { + linker_warning(prog, "shader uses too many varying components " + "(%u > %u), but the driver will try to optimize " + "them out; this is non-portable out-of-spec " + "behavior\n", + float_components, ctx->Const.MaxVarying * 4); + } else { + linker_error(prog, "shader uses too many varying components " + "(%u > %u)\n", + float_components, ctx->Const.MaxVarying * 4); + return false; + } + } + } + + return true; +} |