-/**
- * Data structure tracking information about a transform feedback declaration
- * during linking.
- */
-class tfeedback_decl
-{
-public:
- bool init(struct gl_context *ctx, struct gl_shader_program *prog,
- const void *mem_ctx, const char *input);
- static bool is_same(const tfeedback_decl &x, const tfeedback_decl &y);
- bool assign_location(struct gl_context *ctx, struct gl_shader_program *prog,
- ir_variable *output_var);
- bool store(struct gl_shader_program *prog,
- struct gl_transform_feedback_info *info, unsigned buffer,
- unsigned varying) const;
-
-
- /**
- * True if assign_location() has been called for this object.
- */
- bool is_assigned() const
- {
- return this->location != -1;
- }
-
- /**
- * Determine whether this object refers to the variable var.
- */
- bool matches_var(ir_variable *var) const
- {
- return strcmp(var->name, this->var_name) == 0;
- }
-
- /**
- * The total number of varying components taken up by this variable. Only
- * valid if is_assigned() is true.
- */
- unsigned num_components() const
- {
- return this->vector_elements * this->matrix_columns;
- }
-
-private:
- /**
- * The name that was supplied to glTransformFeedbackVaryings. Used for
- * error reporting and glGetTransformFeedbackVarying().
- */
- const char *orig_name;
-
- /**
- * The name of the variable, parsed from orig_name.
- */
- const char *var_name;
-
- /**
- * True if the declaration in orig_name represents an array.
- */
- bool is_subscripted;
-
- /**
- * If is_subscripted is true, the subscript that was specified in orig_name.
- */
- unsigned array_subscript;
-
- /**
- * Which component to extract from the vertex shader output location that
- * the linker assigned to this variable. -1 if all components should be
- * extracted.
- */
- int single_component;
-
- /**
- * The vertex shader output location that the linker assigned for this
- * variable. -1 if a location hasn't been assigned yet.
- */
- int location;
-
- /**
- * If location != -1, the number of vector elements in this variable, or 1
- * if this variable is a scalar.
- */
- unsigned vector_elements;
-
- /**
- * If location != -1, the number of matrix columns in this variable, or 1
- * if this variable is not a matrix.
- */
- unsigned matrix_columns;
-
- /** Type of the varying returned by glGetTransformFeedbackVarying() */
- GLenum type;
-
- /**
- * If location != -1, the size that should be returned by
- * glGetTransformFeedbackVarying().
- */
- unsigned size;
-};
-
-
-/**
- * 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->single_component = -1;
-
- 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, we need
- * to convert a request for gl_ClipDistance[n] into a request for a
- * component of gl_ClipDistanceMESA[n/4].
- */
- if (ctx->ShaderCompilerOptions[MESA_SHADER_VERTEX].LowerClipDistance &&
- strcmp(this->var_name, "gl_ClipDistance") == 0) {
- this->var_name = "gl_ClipDistanceMESA";
- if (this->is_subscripted) {
- this->single_component = this->array_subscript % 4;
- this->array_subscript /= 4;
- }
- }
-
- 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)
-{
- 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;
- if (x.single_component != y.single_component)
- 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)
-{
- if (output_var->type->is_array()) {
- /* Array variable */
- const unsigned matrix_cols =
- output_var->type->fields.array->matrix_columns;
-
- if (this->is_subscripted) {
- /* Check array bounds. */
- if (this->array_subscript >=
- (unsigned) output_var->type->array_size()) {
- linker_error(prog, "Transform feedback varying %s has index "
- "%i, but the array size is %i.",
- this->orig_name, this->array_subscript,
- output_var->type->array_size());
- return false;
- }
- this->location =
- output_var->location + this->array_subscript * matrix_cols;
- this->size = 1;
- } else {
- this->location = output_var->location;
- this->size = (unsigned) output_var->type->array_size();
- }
- this->vector_elements = output_var->type->fields.array->vector_elements;
- this->matrix_columns = matrix_cols;
- 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->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;
-}
-
-
-/**
- * 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_shader_program *prog,
- struct gl_transform_feedback_info *info,
- unsigned buffer, unsigned varying) const
-{
- if (!this->is_assigned()) {
- /* 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 false;
- }
- for (unsigned index = 0; index < this->size; ++index) {
- for (unsigned v = 0; v < this->matrix_columns; ++v) {
- unsigned num_components =
- this->single_component >= 0 ? 1 : this->vector_elements;
- info->Outputs[info->NumOutputs].OutputRegister =
- this->location + v + index * this->matrix_columns;
- info->Outputs[info->NumOutputs].NumComponents = num_components;
- info->Outputs[info->NumOutputs].OutputBuffer = buffer;
- info->Outputs[info->NumOutputs].DstOffset = info->BufferStride[buffer];
- info->Outputs[info->NumOutputs].ComponentOffset =
- this->single_component >= 0 ? this->single_component : 0;
- ++info->NumOutputs;
- info->BufferStride[buffer] += num_components;
- }
- }
-
- info->Varyings[varying].Name = ralloc_strdup(prog, this->orig_name);
- info->Varyings[varying].Type = this->type;
- info->Varyings[varying].Size = this->size;
- info->NumVarying++;
-
- return true;
-}
-
-
-/**
- * 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) {
- if (!decls[i].init(ctx, prog, mem_ctx, varying_names[i]))
- return false;
- /* 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 (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;
-}
-
-
-/**
- * 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.
- *
- * 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).
- *
- * If the variable has already been assigned a location, this function has no
- * effect.
- */
-void
-assign_varying_location(ir_variable *input_var, ir_variable *output_var,
- unsigned *input_index, unsigned *output_index)
-{
- if (output_var->location != -1) {
- /* Location already assigned. */
- return;
- }
-
- if (input_var) {
- assert(input_var->location == -1);
- input_var->location = *input_index;
- }
-
- output_var->location = *output_index;
-
- /* FINISHME: Support for "varying" records in GLSL 1.50. */
- assert(!output_var->type->is_record());
-
- if (output_var->type->is_array()) {
- const unsigned slots = output_var->type->length
- * output_var->type->fields.array->matrix_columns;
-
- *output_index += slots;
- *input_index += slots;
- } else {
- const unsigned slots = output_var->type->matrix_columns;
-
- *output_index += slots;
- *input_index += 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.
- */
-bool
-assign_varying_locations(struct gl_context *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. */
- unsigned output_index = VERT_RESULT_VAR0;
- unsigned input_index = FRAG_ATTRIB_VAR0;
-
- /* 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.
- */
-
- link_invalidate_variable_locations(producer, ir_var_out, VERT_RESULT_VAR0);
- if (consumer)
- link_invalidate_variable_locations(consumer, ir_var_in, FRAG_ATTRIB_VAR0);
-
- 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) {
- assign_varying_location(input_var, output_var, &input_index,
- &output_index);
- }
-
- for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
- if (!tfeedback_decls[i].is_assigned() &&
- tfeedback_decls[i].matches_var(output_var)) {
- if (output_var->location == -1) {
- assign_varying_location(input_var, output_var, &input_index,
- &output_index);
- }
- if (!tfeedback_decls[i].assign_location(ctx, prog, output_var))
- return false;
- }
- }
- }
-
- 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->location == -1) {
- 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 {
- /* 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->Version == 100) {
- 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;
-}
-
-
-/**
- * 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.
- */
-static bool
-store_tfeedback_info(struct gl_context *ctx, struct gl_shader_program *prog,
- unsigned num_tfeedback_decls,
- tfeedback_decl *tfeedback_decls)
-{
- unsigned total_tfeedback_components = 0;
- bool separate_attribs_mode =
- prog->TransformFeedback.BufferMode == GL_SEPARATE_ATTRIBS;
-
- ralloc_free(prog->LinkedTransformFeedback.Varyings);
-
- memset(&prog->LinkedTransformFeedback, 0,
- sizeof(prog->LinkedTransformFeedback));
-
- prog->LinkedTransformFeedback.NumBuffers =
- separate_attribs_mode ? num_tfeedback_decls : 1;
-
- prog->LinkedTransformFeedback.Varyings =
- rzalloc_array(prog->LinkedTransformFeedback.Varyings,
- struct gl_transform_feedback_varying_info,
- num_tfeedback_decls);
-
- for (unsigned i = 0; i < num_tfeedback_decls; ++i) {
- unsigned buffer = separate_attribs_mode ? i : 0;
- if (!tfeedback_decls[i].store(prog, &prog->LinkedTransformFeedback,
- buffer, i))
- return false;
- total_tfeedback_components += tfeedback_decls[i].num_components();
- }
-
- /* 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 &&
- total_tfeedback_components >
- ctx->Const.MaxTransformFeedbackInterleavedComponents) {
- linker_error(prog, "The MAX_TRANSFORM_FEEDBACK_INTERLEAVED_COMPONENTS "
- "limit has been exceeded.");
- return false;
- }
-
- return true;
-}
-