/* * Copyright © 2010 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 linker.cpp * GLSL linker implementation * * Given a set of shaders that are to be linked to generate a final program, * there are three distinct stages. * * In the first stage shaders are partitioned into groups based on the shader * type. All shaders of a particular type (e.g., vertex shaders) are linked * together. * * - Undefined references in each shader are resolve to definitions in * another shader. * - Types and qualifiers of uniforms, outputs, and global variables defined * in multiple shaders with the same name are verified to be the same. * - Initializers for uniforms and global variables defined * in multiple shaders with the same name are verified to be the same. * * The result, in the terminology of the GLSL spec, is a set of shader * executables for each processing unit. * * After the first stage is complete, a series of semantic checks are performed * on each of the shader executables. * * - Each shader executable must define a \c main function. * - Each vertex shader executable must write to \c gl_Position. * - Each fragment shader executable must write to either \c gl_FragData or * \c gl_FragColor. * * In the final stage individual shader executables are linked to create a * complete exectuable. * * - Types of uniforms defined in multiple shader stages with the same name * are verified to be the same. * - Initializers for uniforms defined in multiple shader stages with the * same name are verified to be the same. * - Types and qualifiers of outputs defined in one stage are verified to * be the same as the types and qualifiers of inputs defined with the same * name in a later stage. * * \author Ian Romanick */ #include "main/core.h" #include "glsl_symbol_table.h" #include "ir.h" #include "program.h" #include "program/hash_table.h" #include "linker.h" #include "ir_optimization.h" extern "C" { #include "main/shaderobj.h" } /** * Visitor that determines whether or not a variable is ever written. */ class find_assignment_visitor : public ir_hierarchical_visitor { public: find_assignment_visitor(const char *name) : name(name), found(false) { /* empty */ } virtual ir_visitor_status visit_enter(ir_assignment *ir) { ir_variable *const var = ir->lhs->variable_referenced(); if (strcmp(name, var->name) == 0) { found = true; return visit_stop; } return visit_continue_with_parent; } virtual ir_visitor_status visit_enter(ir_call *ir) { exec_list_iterator sig_iter = ir->callee->parameters.iterator(); foreach_iter(exec_list_iterator, iter, *ir) { ir_rvalue *param_rval = (ir_rvalue *)iter.get(); ir_variable *sig_param = (ir_variable *)sig_iter.get(); if (sig_param->mode == ir_var_out || sig_param->mode == ir_var_inout) { ir_variable *var = param_rval->variable_referenced(); if (var && strcmp(name, var->name) == 0) { found = true; return visit_stop; } } sig_iter.next(); } if (ir->return_deref != NULL) { ir_variable *const var = ir->return_deref->variable_referenced(); if (strcmp(name, var->name) == 0) { found = true; return visit_stop; } } return visit_continue_with_parent; } bool variable_found() { return found; } private: const char *name; /**< Find writes to a variable with this name. */ bool found; /**< Was a write to the variable found? */ }; /** * Visitor that determines whether or not a variable is ever read. */ class find_deref_visitor : public ir_hierarchical_visitor { public: find_deref_visitor(const char *name) : name(name), found(false) { /* empty */ } virtual ir_visitor_status visit(ir_dereference_variable *ir) { if (strcmp(this->name, ir->var->name) == 0) { this->found = true; return visit_stop; } return visit_continue; } bool variable_found() const { return this->found; } private: const char *name; /**< Find writes to a variable with this name. */ bool found; /**< Was a write to the variable found? */ }; void linker_error(gl_shader_program *prog, const char *fmt, ...) { va_list ap; ralloc_strcat(&prog->InfoLog, "error: "); va_start(ap, fmt); ralloc_vasprintf_append(&prog->InfoLog, fmt, ap); va_end(ap); prog->LinkStatus = false; } void linker_warning(gl_shader_program *prog, const char *fmt, ...) { va_list ap; ralloc_strcat(&prog->InfoLog, "error: "); va_start(ap, fmt); ralloc_vasprintf_append(&prog->InfoLog, fmt, ap); va_end(ap); } void link_invalidate_variable_locations(gl_shader *sh, enum ir_variable_mode mode, int generic_base) { foreach_list(node, sh->ir) { ir_variable *const var = ((ir_instruction *) node)->as_variable(); if ((var == NULL) || (var->mode != (unsigned) mode)) continue; /* Only assign locations for generic attributes / varyings / etc. */ if ((var->location >= generic_base) && !var->explicit_location) var->location = -1; } } /** * Determine the number of attribute slots required for a particular type * * This code is here because it implements the language rules of a specific * GLSL version. Since it's a property of the language and not a property of * types in general, it doesn't really belong in glsl_type. */ unsigned count_attribute_slots(const glsl_type *t) { /* From page 31 (page 37 of the PDF) of the GLSL 1.50 spec: * * "A scalar input counts the same amount against this limit as a vec4, * so applications may want to consider packing groups of four * unrelated float inputs together into a vector to better utilize the * capabilities of the underlying hardware. A matrix input will use up * multiple locations. The number of locations used will equal the * number of columns in the matrix." * * The spec does not explicitly say how arrays are counted. However, it * should be safe to assume the total number of slots consumed by an array * is the number of entries in the array multiplied by the number of slots * consumed by a single element of the array. */ if (t->is_array()) return t->array_size() * count_attribute_slots(t->element_type()); if (t->is_matrix()) return t->matrix_columns; return 1; } /** * Verify that a vertex shader executable meets all semantic requirements. * * Also sets prog->Vert.UsesClipDistance and prog->Vert.ClipDistanceArraySize * as a side effect. * * \param shader Vertex shader executable to be verified */ bool validate_vertex_shader_executable(struct gl_shader_program *prog, struct gl_shader *shader) { if (shader == NULL) return true; /* From the GLSL 1.10 spec, page 48: * * "The variable gl_Position is available only in the vertex * language and is intended for writing the homogeneous vertex * position. All executions of a well-formed vertex shader * executable must write a value into this variable. [...] The * variable gl_Position is available only in the vertex * language and is intended for writing the homogeneous vertex * position. All executions of a well-formed vertex shader * executable must write a value into this variable." * * while in GLSL 1.40 this text is changed to: * * "The variable gl_Position is available only in the vertex * language and is intended for writing the homogeneous vertex * position. It can be written at any time during shader * execution. It may also be read back by a vertex shader * after being written. This value will be used by primitive * assembly, clipping, culling, and other fixed functionality * operations, if present, that operate on primitives after * vertex processing has occurred. Its value is undefined if * the vertex shader executable does not write gl_Position." */ if (prog->Version < 140) { find_assignment_visitor find("gl_Position"); find.run(shader->ir); if (!find.variable_found()) { linker_error(prog, "vertex shader does not write to `gl_Position'\n"); return false; } } prog->Vert.ClipDistanceArraySize = 0; if (prog->Version >= 130) { /* From section 7.1 (Vertex Shader Special Variables) of the * GLSL 1.30 spec: * * "It is an error for a shader to statically write both * gl_ClipVertex and gl_ClipDistance." */ find_assignment_visitor clip_vertex("gl_ClipVertex"); find_assignment_visitor clip_distance("gl_ClipDistance"); clip_vertex.run(shader->ir); clip_distance.run(shader->ir); if (clip_vertex.variable_found() && clip_distance.variable_found()) { linker_error(prog, "vertex shader writes to both `gl_ClipVertex' " "and `gl_ClipDistance'\n"); return false; } prog->Vert.UsesClipDistance = clip_distance.variable_found(); ir_variable *clip_distance_var = shader->symbols->get_variable("gl_ClipDistance"); if (clip_distance_var) prog->Vert.ClipDistanceArraySize = clip_distance_var->type->length; } return true; } /** * Verify that a fragment shader executable meets all semantic requirements * * \param shader Fragment shader executable to be verified */ bool validate_fragment_shader_executable(struct gl_shader_program *prog, struct gl_shader *shader) { if (shader == NULL) return true; find_assignment_visitor frag_color("gl_FragColor"); find_assignment_visitor frag_data("gl_FragData"); frag_color.run(shader->ir); frag_data.run(shader->ir); if (frag_color.variable_found() && frag_data.variable_found()) { linker_error(prog, "fragment shader writes to both " "`gl_FragColor' and `gl_FragData'\n"); return false; } return true; } /** * Generate a string describing the mode of a variable */ static const char * mode_string(const ir_variable *var) { switch (var->mode) { case ir_var_auto: return (var->read_only) ? "global constant" : "global variable"; case ir_var_uniform: return "uniform"; case ir_var_in: return "shader input"; case ir_var_out: return "shader output"; case ir_var_inout: return "shader inout"; case ir_var_const_in: case ir_var_temporary: default: assert(!"Should not get here."); return "invalid variable"; } } /** * Perform validation of global variables used across multiple shaders */ bool cross_validate_globals(struct gl_shader_program *prog, struct gl_shader **shader_list, unsigned num_shaders, bool uniforms_only) { /* Examine all of the uniforms in all of the shaders and cross validate * them. */ glsl_symbol_table variables; for (unsigned i = 0; i < num_shaders; i++) { if (shader_list[i] == NULL) continue; foreach_list(node, shader_list[i]->ir) { ir_variable *const var = ((ir_instruction *) node)->as_variable(); if (var == NULL) continue; if (uniforms_only && (var->mode != ir_var_uniform)) continue; /* Don't cross validate temporaries that are at global scope. These * will eventually get pulled into the shaders 'main'. */ if (var->mode == ir_var_temporary) continue; /* If a global with this name has already been seen, verify that the * new instance has the same type. In addition, if the globals have * initializers, the values of the initializers must be the same. */ ir_variable *const existing = variables.get_variable(var->name); if (existing != NULL) { if (var->type != existing->type) { /* Consider the types to be "the same" if both types are arrays * of the same type and one of the arrays is implicitly sized. * In addition, set the type of the linked variable to the * explicitly sized array. */ if (var->type->is_array() && existing->type->is_array() && (var->type->fields.array == existing->type->fields.array) && ((var->type->length == 0) || (existing->type->length == 0))) { if (var->type->length != 0) { existing->type = var->type; } } else { linker_error(prog, "%s `%s' declared as type " "`%s' and type `%s'\n", mode_string(var), var->name, var->type->name, existing->type->name); return false; } } if (var->explicit_location) { if (existing->explicit_location && (var->location != existing->location)) { linker_error(prog, "explicit locations for %s " "`%s' have differing values\n", mode_string(var), var->name); return false; } existing->location = var->location; existing->explicit_location = true; } /* Validate layout qualifiers for gl_FragDepth. * * From the AMD/ARB_conservative_depth specs: * * "If gl_FragDepth is redeclared in any fragment shader in a * program, it must be redeclared in all fragment shaders in * that program that have static assignments to * gl_FragDepth. All redeclarations of gl_FragDepth in all * fragment shaders in a single program must have the same set * of qualifiers." */ if (strcmp(var->name, "gl_FragDepth") == 0) { bool layout_declared = var->depth_layout != ir_depth_layout_none; bool layout_differs = var->depth_layout != existing->depth_layout; if (layout_declared && layout_differs) { linker_error(prog, "All redeclarations of gl_FragDepth in all " "fragment shaders in a single program must have " "the same set of qualifiers."); } if (var->used && layout_differs) { linker_error(prog, "If gl_FragDepth is redeclared with a layout " "qualifier in any fragment shader, it must be " "redeclared with the same layout qualifier in " "all fragment shaders that have assignments to " "gl_FragDepth"); } } /* Page 35 (page 41 of the PDF) of the GLSL 4.20 spec says: * * "If a shared global has multiple initializers, the * initializers must all be constant expressions, and they * must all have the same value. Otherwise, a link error will * result. (A shared global having only one initializer does * not require that initializer to be a constant expression.)" * * Previous to 4.20 the GLSL spec simply said that initializers * must have the same value. In this case of non-constant * initializers, this was impossible to determine. As a result, * no vendor actually implemented that behavior. The 4.20 * behavior matches the implemented behavior of at least one other * vendor, so we'll implement that for all GLSL versions. */ if (var->constant_initializer != NULL) { if (existing->constant_initializer != NULL) { if (!var->constant_initializer->has_value(existing->constant_initializer)) { linker_error(prog, "initializers for %s " "`%s' have differing values\n", mode_string(var), var->name); return false; } } else { /* If the first-seen instance of a particular uniform did not * have an initializer but a later instance does, copy the * initializer to the version stored in the symbol table. */ /* FINISHME: This is wrong. The constant_value field should * FINISHME: not be modified! Imagine a case where a shader * FINISHME: without an initializer is linked in two different * FINISHME: programs with shaders that have differing * FINISHME: initializers. Linking with the first will * FINISHME: modify the shader, and linking with the second * FINISHME: will fail. */ existing->constant_initializer = var->constant_initializer->clone(ralloc_parent(existing), NULL); } } if (var->has_initializer) { if (existing->has_initializer && (var->constant_initializer == NULL || existing->constant_initializer == NULL)) { linker_error(prog, "shared global variable `%s' has multiple " "non-constant initializers.\n", var->name); return false; } /* Some instance had an initializer, so keep track of that. In * this location, all sorts of initializers (constant or * otherwise) will propagate the existence to the variable * stored in the symbol table. */ existing->has_initializer = true; } if (existing->invariant != var->invariant) { linker_error(prog, "declarations for %s `%s' have " "mismatching invariant qualifiers\n", mode_string(var), var->name); return false; } if (existing->centroid != var->centroid) { linker_error(prog, "declarations for %s `%s' have " "mismatching centroid qualifiers\n", mode_string(var), var->name); return false; } } else variables.add_variable(var); } } return true; } /** * Perform validation of uniforms used across multiple shader stages */ bool cross_validate_uniforms(struct gl_shader_program *prog) { return cross_validate_globals(prog, prog->_LinkedShaders, MESA_SHADER_TYPES, true); } /** * 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; } /** * Populates a shaders symbol table with all global declarations */ static void populate_symbol_table(gl_shader *sh) { sh->symbols = new(sh) glsl_symbol_table; foreach_list(node, sh->ir) { ir_instruction *const inst = (ir_instruction *) node; ir_variable *var; ir_function *func; if ((func = inst->as_function()) != NULL) { sh->symbols->add_function(func); } else if ((var = inst->as_variable()) != NULL) { sh->symbols->add_variable(var); } } } /** * Remap variables referenced in an instruction tree * * This is used when instruction trees are cloned from one shader and placed in * another. These trees will contain references to \c ir_variable nodes that * do not exist in the target shader. This function finds these \c ir_variable * references and replaces the references with matching variables in the target * shader. * * If there is no matching variable in the target shader, a clone of the * \c ir_variable is made and added to the target shader. The new variable is * added to \b both the instruction stream and the symbol table. * * \param inst IR tree that is to be processed. * \param symbols Symbol table containing global scope symbols in the * linked shader. * \param instructions Instruction stream where new variable declarations * should be added. */ void remap_variables(ir_instruction *inst, struct gl_shader *target, hash_table *temps) { class remap_visitor : public ir_hierarchical_visitor { public: remap_visitor(struct gl_shader *target, hash_table *temps) { this->target = target; this->symbols = target->symbols; this->instructions = target->ir; this->temps = temps; } virtual ir_visitor_status visit(ir_dereference_variable *ir) { if (ir->var->mode == ir_var_temporary) { ir_variable *var = (ir_variable *) hash_table_find(temps, ir->var); assert(var != NULL); ir->var = var; return visit_continue; } ir_variable *const existing = this->symbols->get_variable(ir->var->name); if (existing != NULL) ir->var = existing; else { ir_variable *copy = ir->var->clone(this->target, NULL); this->symbols->add_variable(copy); this->instructions->push_head(copy); ir->var = copy; } return visit_continue; } private: struct gl_shader *target; glsl_symbol_table *symbols; exec_list *instructions; hash_table *temps; }; remap_visitor v(target, temps); inst->accept(&v); } /** * Move non-declarations from one instruction stream to another * * The intended usage pattern of this function is to pass the pointer to the * head sentinel of a list (i.e., a pointer to the list cast to an \c exec_node * pointer) for \c last and \c false for \c make_copies on the first * call. Successive calls pass the return value of the previous call for * \c last and \c true for \c make_copies. * * \param instructions Source instruction stream * \param last Instruction after which new instructions should be * inserted in the target instruction stream * \param make_copies Flag selecting whether instructions in \c instructions * should be copied (via \c ir_instruction::clone) into the * target list or moved. * * \return * The new "last" instruction in the target instruction stream. This pointer * is suitable for use as the \c last parameter of a later call to this * function. */ exec_node * move_non_declarations(exec_list *instructions, exec_node *last, bool make_copies, gl_shader *target) { hash_table *temps = NULL; if (make_copies) temps = hash_table_ctor(0, hash_table_pointer_hash, hash_table_pointer_compare); foreach_list_safe(node, instructions) { ir_instruction *inst = (ir_instruction *) node; if (inst->as_function()) continue; ir_variable *var = inst->as_variable(); if ((var != NULL) && (var->mode != ir_var_temporary)) continue; assert(inst->as_assignment() || inst->as_call() || ((var != NULL) && (var->mode == ir_var_temporary))); if (make_copies) { inst = inst->clone(target, NULL); if (var != NULL) hash_table_insert(temps, inst, var); else remap_variables(inst, target, temps); } else { inst->remove(); } last->insert_after(inst); last = inst; } if (make_copies) hash_table_dtor(temps); return last; } /** * Get the function signature for main from a shader */ static ir_function_signature * get_main_function_signature(gl_shader *sh) { ir_function *const f = sh->symbols->get_function("main"); if (f != NULL) { exec_list void_parameters; /* Look for the 'void main()' signature and ensure that it's defined. * This keeps the linker from accidentally pick a shader that just * contains a prototype for main. * * We don't have to check for multiple definitions of main (in multiple * shaders) because that would have already been caught above. */ ir_function_signature *sig = f->matching_signature(&void_parameters); if ((sig != NULL) && sig->is_defined) { return sig; } } return NULL; } /** * This class is only used in link_intrastage_shaders() below but declaring * it inside that function leads to compiler warnings with some versions of * gcc. */ class array_sizing_visitor : public ir_hierarchical_visitor { public: virtual ir_visitor_status visit(ir_variable *var) { if (var->type->is_array() && (var->type->length == 0)) { const glsl_type *type = glsl_type::get_array_instance(var->type->fields.array, var->max_array_access + 1); assert(type != NULL); var->type = type; } return visit_continue; } }; /** * Combine a group of shaders for a single stage to generate a linked shader * * \note * If this function is supplied a single shader, it is cloned, and the new * shader is returned. */ static struct gl_shader * link_intrastage_shaders(void *mem_ctx, struct gl_context *ctx, struct gl_shader_program *prog, struct gl_shader **shader_list, unsigned num_shaders) { /* Check that global variables defined in multiple shaders are consistent. */ if (!cross_validate_globals(prog, shader_list, num_shaders, false)) return NULL; /* Check that there is only a single definition of each function signature * across all shaders. */ for (unsigned i = 0; i < (num_shaders - 1); i++) { foreach_list(node, shader_list[i]->ir) { ir_function *const f = ((ir_instruction *) node)->as_function(); if (f == NULL) continue; for (unsigned j = i + 1; j < num_shaders; j++) { ir_function *const other = shader_list[j]->symbols->get_function(f->name); /* If the other shader has no function (and therefore no function * signatures) with the same name, skip to the next shader. */ if (other == NULL) continue; foreach_iter (exec_list_iterator, iter, *f) { ir_function_signature *sig = (ir_function_signature *) iter.get(); if (!sig->is_defined || sig->is_builtin) continue; ir_function_signature *other_sig = other->exact_matching_signature(& sig->parameters); if ((other_sig != NULL) && other_sig->is_defined && !other_sig->is_builtin) { linker_error(prog, "function `%s' is multiply defined", f->name); return NULL; } } } } } /* Find the shader that defines main, and make a clone of it. * * Starting with the clone, search for undefined references. If one is * found, find the shader that defines it. Clone the reference and add * it to the shader. Repeat until there are no undefined references or * until a reference cannot be resolved. */ gl_shader *main = NULL; for (unsigned i = 0; i < num_shaders; i++) { if (get_main_function_signature(shader_list[i]) != NULL) { main = shader_list[i]; break; } } if (main == NULL) { linker_error(prog, "%s shader lacks `main'\n", (shader_list[0]->Type == GL_VERTEX_SHADER) ? "vertex" : "fragment"); return NULL; } gl_shader *linked = ctx->Driver.NewShader(NULL, 0, main->Type); linked->ir = new(linked) exec_list; clone_ir_list(mem_ctx, linked->ir, main->ir); populate_symbol_table(linked); /* The a pointer to the main function in the final linked shader (i.e., the * copy of the original shader that contained the main function). */ ir_function_signature *const main_sig = get_main_function_signature(linked); /* Move any instructions other than variable declarations or function * declarations into main. */ exec_node *insertion_point = move_non_declarations(linked->ir, (exec_node *) &main_sig->body, false, linked); for (unsigned i = 0; i < num_shaders; i++) { if (shader_list[i] == main) continue; insertion_point = move_non_declarations(shader_list[i]->ir, insertion_point, true, linked); } /* Resolve initializers for global variables in the linked shader. */ unsigned num_linking_shaders = num_shaders; for (unsigned i = 0; i < num_shaders; i++) num_linking_shaders += shader_list[i]->num_builtins_to_link; gl_shader **linking_shaders = (gl_shader **) calloc(num_linking_shaders, sizeof(gl_shader *)); memcpy(linking_shaders, shader_list, sizeof(linking_shaders[0]) * num_shaders); unsigned idx = num_shaders; for (unsigned i = 0; i < num_shaders; i++) { memcpy(&linking_shaders[idx], shader_list[i]->builtins_to_link, sizeof(linking_shaders[0]) * shader_list[i]->num_builtins_to_link); idx += shader_list[i]->num_builtins_to_link; } assert(idx == num_linking_shaders); if (!link_function_calls(prog, linked, linking_shaders, num_linking_shaders)) { ctx->Driver.DeleteShader(ctx, linked); linked = NULL; } free(linking_shaders); #ifdef DEBUG /* At this point linked should contain all of the linked IR, so * validate it to make sure nothing went wrong. */ if (linked) validate_ir_tree(linked->ir); #endif /* Make a pass over all variable declarations to ensure that arrays with * unspecified sizes have a size specified. The size is inferred from the * max_array_access field. */ if (linked != NULL) { array_sizing_visitor v; v.run(linked->ir); } return linked; } /** * Update the sizes of linked shader uniform arrays to the maximum * array index used. * * From page 81 (page 95 of the PDF) of the OpenGL 2.1 spec: * * If one or more elements of an array are active, * GetActiveUniform will return the name of the array in name, * subject to the restrictions listed above. The type of the array * is returned in type. The size parameter contains the highest * array element index used, plus one. The compiler or linker * determines the highest index used. There will be only one * active uniform reported by the GL per uniform array. */ static void update_array_sizes(struct gl_shader_program *prog) { for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) { if (prog->_LinkedShaders[i] == NULL) continue; foreach_list(node, prog->_LinkedShaders[i]->ir) { ir_variable *const var = ((ir_instruction *) node)->as_variable(); if ((var == NULL) || (var->mode != ir_var_uniform && var->mode != ir_var_in && var->mode != ir_var_out) || !var->type->is_array()) continue; unsigned int size = var->max_array_access; for (unsigned j = 0; j < MESA_SHADER_TYPES; j++) { if (prog->_LinkedShaders[j] == NULL) continue; foreach_list(node2, prog->_LinkedShaders[j]->ir) { ir_variable *other_var = ((ir_instruction *) node2)->as_variable(); if (!other_var) continue; if (strcmp(var->name, other_var->name) == 0 && other_var->max_array_access > size) { size = other_var->max_array_access; } } } if (size + 1 != var->type->fields.array->length) { /* If this is a built-in uniform (i.e., it's backed by some * fixed-function state), adjust the number of state slots to * match the new array size. The number of slots per array entry * is not known. It seems safe to assume that the total number of * slots is an integer multiple of the number of array elements. * Determine the number of slots per array element by dividing by * the old (total) size. */ if (var->num_state_slots > 0) { var->num_state_slots = (size + 1) * (var->num_state_slots / var->type->length); } var->type = glsl_type::get_array_instance(var->type->fields.array, size + 1); /* FINISHME: We should update the types of array * dereferences of this variable now. */ } } } } /** * Find a contiguous set of available bits in a bitmask. * * \param used_mask Bits representing used (1) and unused (0) locations * \param needed_count Number of contiguous bits needed. * * \return * Base location of the available bits on success or -1 on failure. */ int find_available_slots(unsigned used_mask, unsigned needed_count) { unsigned needed_mask = (1 << needed_count) - 1; const int max_bit_to_test = (8 * sizeof(used_mask)) - needed_count; /* The comparison to 32 is redundant, but without it GCC emits "warning: * cannot optimize possibly infinite loops" for the loop below. */ if ((needed_count == 0) || (max_bit_to_test < 0) || (max_bit_to_test > 32)) return -1; for (int i = 0; i <= max_bit_to_test; i++) { if ((needed_mask & ~used_mask) == needed_mask) return i; needed_mask <<= 1; } return -1; } /** * Assign locations for either VS inputs for FS outputs * * \param prog Shader program whose variables need locations assigned * \param target_index Selector for the program target to receive location * assignmnets. Must be either \c MESA_SHADER_VERTEX or * \c MESA_SHADER_FRAGMENT. * \param max_index Maximum number of generic locations. This corresponds * to either the maximum number of draw buffers or the * maximum number of generic attributes. * * \return * If locations are successfully assigned, true is returned. Otherwise an * error is emitted to the shader link log and false is returned. */ bool assign_attribute_or_color_locations(gl_shader_program *prog, unsigned target_index, unsigned max_index) { /* Mark invalid locations as being used. */ unsigned used_locations = (max_index >= 32) ? ~0 : ~((1 << max_index) - 1); assert((target_index == MESA_SHADER_VERTEX) || (target_index == MESA_SHADER_FRAGMENT)); gl_shader *const sh = prog->_LinkedShaders[target_index]; if (sh == NULL) return true; /* Operate in a total of four passes. * * 1. Invalidate the location assignments for all vertex shader inputs. * * 2. Assign locations for inputs that have user-defined (via * glBindVertexAttribLocation) locations and outputs that have * user-defined locations (via glBindFragDataLocation). * * 3. Sort the attributes without assigned locations by number of slots * required in decreasing order. Fragmentation caused by attribute * locations assigned by the application may prevent large attributes * from having enough contiguous space. * * 4. Assign locations to any inputs without assigned locations. */ const int generic_base = (target_index == MESA_SHADER_VERTEX) ? (int) VERT_ATTRIB_GENERIC0 : (int) FRAG_RESULT_DATA0; const enum ir_variable_mode direction = (target_index == MESA_SHADER_VERTEX) ? ir_var_in : ir_var_out; link_invalidate_variable_locations(sh, direction, generic_base); /* Temporary storage for the set of attributes that need locations assigned. */ struct temp_attr { unsigned slots; ir_variable *var; /* Used below in the call to qsort. */ static int compare(const void *a, const void *b) { const temp_attr *const l = (const temp_attr *) a; const temp_attr *const r = (const temp_attr *) b; /* Reversed because we want a descending order sort below. */ return r->slots - l->slots; } } to_assign[16]; unsigned num_attr = 0; foreach_list(node, sh->ir) { ir_variable *const var = ((ir_instruction *) node)->as_variable(); if ((var == NULL) || (var->mode != (unsigned) direction)) continue; if (var->explicit_location) { if ((var->location >= (int)(max_index + generic_base)) || (var->location < 0)) { linker_error(prog, "invalid explicit location %d specified for `%s'\n", (var->location < 0) ? var->location : var->location - generic_base, var->name); return false; } } else if (target_index == MESA_SHADER_VERTEX) { unsigned binding; if (prog->AttributeBindings->get(binding, var->name)) { assert(binding >= VERT_ATTRIB_GENERIC0); var->location = binding; } } else if (target_index == MESA_SHADER_FRAGMENT) { unsigned binding; unsigned index; if (prog->FragDataBindings->get(binding, var->name)) { assert(binding >= FRAG_RESULT_DATA0); var->location = binding; if (prog->FragDataIndexBindings->get(index, var->name)) { var->index = index; } } } /* If the variable is not a built-in and has a location statically * assigned in the shader (presumably via a layout qualifier), make sure * that it doesn't collide with other assigned locations. Otherwise, * add it to the list of variables that need linker-assigned locations. */ const unsigned slots = count_attribute_slots(var->type); if (var->location != -1) { if (var->location >= generic_base && var->index < 1) { /* From page 61 of the OpenGL 4.0 spec: * * "LinkProgram will fail if the attribute bindings assigned * by BindAttribLocation do not leave not enough space to * assign a location for an active matrix attribute or an * active attribute array, both of which require multiple * contiguous generic attributes." * * Previous versions of the spec contain similar language but omit * the bit about attribute arrays. * * Page 61 of the OpenGL 4.0 spec also says: * * "It is possible for an application to bind more than one * attribute name to the same location. This is referred to as * aliasing. This will only work if only one of the aliased * attributes is active in the executable program, or if no * path through the shader consumes more than one attribute of * a set of attributes aliased to the same location. A link * error can occur if the linker determines that every path * through the shader consumes multiple aliased attributes, * but implementations are not required to generate an error * in this case." * * These two paragraphs are either somewhat contradictory, or I * don't fully understand one or both of them. */ /* FINISHME: The code as currently written does not support * FINISHME: attribute location aliasing (see comment above). */ /* Mask representing the contiguous slots that will be used by * this attribute. */ const unsigned attr = var->location - generic_base; const unsigned use_mask = (1 << slots) - 1; /* Generate a link error if the set of bits requested for this * attribute overlaps any previously allocated bits. */ if ((~(use_mask << attr) & used_locations) != used_locations) { const char *const string = (target_index == MESA_SHADER_VERTEX) ? "vertex shader input" : "fragment shader output"; linker_error(prog, "insufficient contiguous locations " "available for %s `%s' %d %d %d", string, var->name, used_locations, use_mask, attr); return false; } used_locations |= (use_mask << attr); } continue; } to_assign[num_attr].slots = slots; to_assign[num_attr].var = var; num_attr++; } /* If all of the attributes were assigned locations by the application (or * are built-in attributes with fixed locations), return early. This should * be the common case. */ if (num_attr == 0) return true; qsort(to_assign, num_attr, sizeof(to_assign[0]), temp_attr::compare); if (target_index == MESA_SHADER_VERTEX) { /* VERT_ATTRIB_GENERIC0 is a pseudo-alias for VERT_ATTRIB_POS. It can * only be explicitly assigned by via glBindAttribLocation. Mark it as * reserved to prevent it from being automatically allocated below. */ find_deref_visitor find("gl_Vertex"); find.run(sh->ir); if (find.variable_found()) used_locations |= (1 << 0); } for (unsigned i = 0; i < num_attr; i++) { /* Mask representing the contiguous slots that will be used by this * attribute. */ const unsigned use_mask = (1 << to_assign[i].slots) - 1; int location = find_available_slots(used_locations, to_assign[i].slots); if (location < 0) { const char *const string = (target_index == MESA_SHADER_VERTEX) ? "vertex shader input" : "fragment shader output"; linker_error(prog, "insufficient contiguous locations " "available for %s `%s'", string, to_assign[i].var->name); return false; } to_assign[i].var->location = generic_base + location; used_locations |= (use_mask << location); } return true; } /** * Demote shader inputs and outputs that are not used in other stages */ void demote_shader_inputs_and_outputs(gl_shader *sh, enum ir_variable_mode mode) { foreach_list(node, sh->ir) { ir_variable *const var = ((ir_instruction *) node)->as_variable(); if ((var == NULL) || (var->mode != int(mode))) continue; /* A shader 'in' or 'out' variable is only really an input or output if * its value is used by other shader stages. This will cause the variable * to have a location assigned. */ if (var->location == -1) { var->mode = ir_var_auto; } } } /** * 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 accumulate_num_outputs(struct gl_shader_program *prog, unsigned *count); bool store(struct gl_context *ctx, struct gl_shader_program *prog, struct gl_transform_feedback_info *info, unsigned buffer, const unsigned max_outputs) const; /** * True if assign_location() has been called for this object. */ bool is_assigned() const { return this->location != -1; } bool is_next_buffer_separator() const { return this->next_buffer_separator; } bool is_varying() const { return !this->next_buffer_separator && !this->skip_components; } /** * Determine whether this object refers to the variable var. */ bool matches_var(ir_variable *var) const { if (this->is_clip_distance_mesa) return strcmp(var->name, "gl_ClipDistanceMESA") == 0; else 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 { if (this->is_clip_distance_mesa) return this->size; else return this->vector_elements * this->matrix_columns * this->size; } 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; /** * True if the variable is gl_ClipDistance and the driver lowers * gl_ClipDistance to gl_ClipDistanceMESA. */ bool is_clip_distance_mesa; /** * 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; /** * How many components to skip. If non-zero, this is * gl_SkipComponents{1,2,3,4} from ARB_transform_feedback3. */ unsigned skip_components; /** * Whether this is gl_NextBuffer from ARB_transform_feedback3. */ bool next_buffer_separator; }; /** * 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; 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; } else { this->location = output_var->location + this->array_subscript * matrix_cols; } this->size = 1; } else { this->location = output_var->location; this->size = actual_array_size; } this->vector_elements = output_var->type->fields.array->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->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 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; } bool tfeedback_decl::accumulate_num_outputs(struct gl_shader_program *prog, unsigned *count) { if (!this->is_varying()) { return true; } if (!this->is_assigned()) { /* From GL_EXT_transform_feedback: * A program will fail to link if: * * * any variable name specified in the 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; } unsigned translated_size = this->size; if (this->is_clip_distance_mesa) translated_size = (translated_size + 3) / 4; *count += translated_size * this->matrix_columns; 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_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 translated_size = this->size; if (this->is_clip_distance_mesa) translated_size = (translated_size + 3) / 4; unsigned components_so_far = 0; for (unsigned index = 0; index < translated_size; ++index) { for (unsigned v = 0; v < this->matrix_columns; ++v) { unsigned num_components = this->vector_elements; assert(info->NumOutputs < max_outputs); info->Outputs[info->NumOutputs].ComponentOffset = 0; if (this->is_clip_distance_mesa) { if (this->is_subscripted) { num_components = 1; info->Outputs[info->NumOutputs].ComponentOffset = this->array_subscript % 4; } else { num_components = MIN2(4, this->size - components_so_far); } } 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->NumOutputs; info->BufferStride[buffer] += num_components; components_so_far += num_components; } } assert(components_so_far == this->num_components()); 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; } /** * 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; if (!decls[i].is_varying()) continue; /* From GL_EXT_transform_feedback: * A program will fail to link if: * * * any two entries in the array specify the same varying * variable; * * We interpret this to mean "any two entries in the 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; } /** * 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; } } /** * 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 && var->explicit_location) { 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, 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_varying()) continue; 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 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->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) { 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) if (!tfeedback_decls[i].accumulate_num_outputs(prog, &num_outputs)) return false; 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; } /** * Store the gl_FragDepth layout in the gl_shader_program struct. */ static void store_fragdepth_layout(struct gl_shader_program *prog) { if (prog->_LinkedShaders[MESA_SHADER_FRAGMENT] == NULL) { return; } struct exec_list *ir = prog->_LinkedShaders[MESA_SHADER_FRAGMENT]->ir; /* We don't look up the gl_FragDepth symbol directly because if * gl_FragDepth is not used in the shader, it's removed from the IR. * However, the symbol won't be removed from the symbol table. * * We're only interested in the cases where the variable is NOT removed * from the IR. */ foreach_list(node, ir) { ir_variable *const var = ((ir_instruction *) node)->as_variable(); if (var == NULL || var->mode != ir_var_out) { continue; } if (strcmp(var->name, "gl_FragDepth") == 0) { switch (var->depth_layout) { case ir_depth_layout_none: prog->FragDepthLayout = FRAG_DEPTH_LAYOUT_NONE; return; case ir_depth_layout_any: prog->FragDepthLayout = FRAG_DEPTH_LAYOUT_ANY; return; case ir_depth_layout_greater: prog->FragDepthLayout = FRAG_DEPTH_LAYOUT_GREATER; return; case ir_depth_layout_less: prog->FragDepthLayout = FRAG_DEPTH_LAYOUT_LESS; return; case ir_depth_layout_unchanged: prog->FragDepthLayout = FRAG_DEPTH_LAYOUT_UNCHANGED; return; default: assert(0); return; } } } } /** * Validate the resources used by a program versus the implementation limits */ static bool check_resources(struct gl_context *ctx, struct gl_shader_program *prog) { static const char *const shader_names[MESA_SHADER_TYPES] = { "vertex", "fragment", "geometry" }; const unsigned max_samplers[MESA_SHADER_TYPES] = { ctx->Const.MaxVertexTextureImageUnits, ctx->Const.MaxTextureImageUnits, ctx->Const.MaxGeometryTextureImageUnits }; const unsigned max_uniform_components[MESA_SHADER_TYPES] = { ctx->Const.VertexProgram.MaxUniformComponents, ctx->Const.FragmentProgram.MaxUniformComponents, 0 /* FINISHME: Geometry shaders. */ }; for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) { struct gl_shader *sh = prog->_LinkedShaders[i]; if (sh == NULL) continue; if (sh->num_samplers > max_samplers[i]) { linker_error(prog, "Too many %s shader texture samplers", shader_names[i]); } if (sh->num_uniform_components > max_uniform_components[i]) { if (ctx->Const.GLSLSkipStrictMaxUniformLimitCheck) { linker_warning(prog, "Too many %s shader uniform components, " "but the driver will try to optimize them out; " "this is non-portable out-of-spec behavior\n", shader_names[i]); } else { linker_error(prog, "Too many %s shader uniform components", shader_names[i]); } } } return prog->LinkStatus; } void link_shaders(struct gl_context *ctx, struct gl_shader_program *prog) { tfeedback_decl *tfeedback_decls = NULL; unsigned num_tfeedback_decls = prog->TransformFeedback.NumVarying; void *mem_ctx = ralloc_context(NULL); // temporary linker context prog->LinkStatus = false; prog->Validated = false; prog->_Used = false; if (prog->InfoLog != NULL) ralloc_free(prog->InfoLog); prog->InfoLog = ralloc_strdup(NULL, ""); /* Separate the shaders into groups based on their type. */ struct gl_shader **vert_shader_list; unsigned num_vert_shaders = 0; struct gl_shader **frag_shader_list; unsigned num_frag_shaders = 0; vert_shader_list = (struct gl_shader **) calloc(2 * prog->NumShaders, sizeof(struct gl_shader *)); frag_shader_list = &vert_shader_list[prog->NumShaders]; unsigned min_version = UINT_MAX; unsigned max_version = 0; for (unsigned i = 0; i < prog->NumShaders; i++) { min_version = MIN2(min_version, prog->Shaders[i]->Version); max_version = MAX2(max_version, prog->Shaders[i]->Version); switch (prog->Shaders[i]->Type) { case GL_VERTEX_SHADER: vert_shader_list[num_vert_shaders] = prog->Shaders[i]; num_vert_shaders++; break; case GL_FRAGMENT_SHADER: frag_shader_list[num_frag_shaders] = prog->Shaders[i]; num_frag_shaders++; break; case GL_GEOMETRY_SHADER: /* FINISHME: Support geometry shaders. */ assert(prog->Shaders[i]->Type != GL_GEOMETRY_SHADER); break; } } /* Previous to GLSL version 1.30, different compilation units could mix and * match shading language versions. With GLSL 1.30 and later, the versions * of all shaders must match. */ assert(min_version >= 100); assert(max_version <= 140); if ((max_version >= 130 || min_version == 100) && min_version != max_version) { linker_error(prog, "all shaders must use same shading " "language version\n"); goto done; } prog->Version = max_version; for (unsigned int i = 0; i < MESA_SHADER_TYPES; i++) { if (prog->_LinkedShaders[i] != NULL) ctx->Driver.DeleteShader(ctx, prog->_LinkedShaders[i]); prog->_LinkedShaders[i] = NULL; } /* Link all shaders for a particular stage and validate the result. */ if (num_vert_shaders > 0) { gl_shader *const sh = link_intrastage_shaders(mem_ctx, ctx, prog, vert_shader_list, num_vert_shaders); if (sh == NULL) goto done; if (!validate_vertex_shader_executable(prog, sh)) goto done; _mesa_reference_shader(ctx, &prog->_LinkedShaders[MESA_SHADER_VERTEX], sh); } if (num_frag_shaders > 0) { gl_shader *const sh = link_intrastage_shaders(mem_ctx, ctx, prog, frag_shader_list, num_frag_shaders); if (sh == NULL) goto done; if (!validate_fragment_shader_executable(prog, sh)) goto done; _mesa_reference_shader(ctx, &prog->_LinkedShaders[MESA_SHADER_FRAGMENT], sh); } /* Here begins the inter-stage linking phase. Some initial validation is * performed, then locations are assigned for uniforms, attributes, and * varyings. */ if (cross_validate_uniforms(prog)) { unsigned prev; for (prev = 0; prev < MESA_SHADER_TYPES; prev++) { if (prog->_LinkedShaders[prev] != NULL) break; } /* Validate the inputs of each stage with the output of the preceding * stage. */ for (unsigned i = prev + 1; i < MESA_SHADER_TYPES; i++) { if (prog->_LinkedShaders[i] == NULL) continue; if (!cross_validate_outputs_to_inputs(prog, prog->_LinkedShaders[prev], prog->_LinkedShaders[i])) goto done; prev = i; } prog->LinkStatus = true; } /* Implement the GLSL 1.30+ rule for discard vs infinite loops Do * it before optimization because we want most of the checks to get * dropped thanks to constant propagation. */ if (max_version >= 130) { struct gl_shader *sh = prog->_LinkedShaders[MESA_SHADER_FRAGMENT]; if (sh) { lower_discard_flow(sh->ir); } } /* Do common optimization before assigning storage for attributes, * uniforms, and varyings. Later optimization could possibly make * some of that unused. */ for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) { if (prog->_LinkedShaders[i] == NULL) continue; detect_recursion_linked(prog, prog->_LinkedShaders[i]->ir); if (!prog->LinkStatus) goto done; if (ctx->ShaderCompilerOptions[i].LowerClipDistance) lower_clip_distance(prog->_LinkedShaders[i]->ir); unsigned max_unroll = ctx->ShaderCompilerOptions[i].MaxUnrollIterations; while (do_common_optimization(prog->_LinkedShaders[i]->ir, true, false, max_unroll)) ; } /* FINISHME: The value of the max_attribute_index parameter is * FINISHME: implementation dependent based on the value of * FINISHME: GL_MAX_VERTEX_ATTRIBS. GL_MAX_VERTEX_ATTRIBS must be * FINISHME: at least 16, so hardcode 16 for now. */ if (!assign_attribute_or_color_locations(prog, MESA_SHADER_VERTEX, 16)) { goto done; } if (!assign_attribute_or_color_locations(prog, MESA_SHADER_FRAGMENT, MAX2(ctx->Const.MaxDrawBuffers, ctx->Const.MaxDualSourceDrawBuffers))) { goto done; } unsigned prev; for (prev = 0; prev < MESA_SHADER_TYPES; prev++) { if (prog->_LinkedShaders[prev] != NULL) break; } if (num_tfeedback_decls != 0) { /* From GL_EXT_transform_feedback: * A program will fail to link if: * * * the specified by TransformFeedbackVaryingsEXT is * non-zero, but the program object has no vertex or geometry * shader; */ if (prev >= MESA_SHADER_FRAGMENT) { linker_error(prog, "Transform feedback varyings specified, but " "no vertex or geometry shader is present."); goto done; } tfeedback_decls = ralloc_array(mem_ctx, tfeedback_decl, prog->TransformFeedback.NumVarying); if (!parse_tfeedback_decls(ctx, prog, mem_ctx, num_tfeedback_decls, prog->TransformFeedback.VaryingNames, tfeedback_decls)) goto done; } for (unsigned i = prev + 1; i < MESA_SHADER_TYPES; i++) { if (prog->_LinkedShaders[i] == NULL) continue; if (!assign_varying_locations( ctx, prog, prog->_LinkedShaders[prev], prog->_LinkedShaders[i], i == MESA_SHADER_FRAGMENT ? num_tfeedback_decls : 0, tfeedback_decls)) goto done; prev = i; } if (prev != MESA_SHADER_FRAGMENT && num_tfeedback_decls != 0) { /* There was no fragment shader, but we still have to assign varying * locations for use by transform feedback. */ if (!assign_varying_locations( ctx, prog, prog->_LinkedShaders[prev], NULL, num_tfeedback_decls, tfeedback_decls)) goto done; } if (!store_tfeedback_info(ctx, prog, num_tfeedback_decls, tfeedback_decls)) goto done; if (prog->_LinkedShaders[MESA_SHADER_VERTEX] != NULL) { demote_shader_inputs_and_outputs(prog->_LinkedShaders[MESA_SHADER_VERTEX], ir_var_out); /* Eliminate code that is now dead due to unused vertex outputs being * demoted. */ while (do_dead_code(prog->_LinkedShaders[MESA_SHADER_VERTEX]->ir, false)) ; } if (prog->_LinkedShaders[MESA_SHADER_GEOMETRY] != NULL) { gl_shader *const sh = prog->_LinkedShaders[MESA_SHADER_GEOMETRY]; demote_shader_inputs_and_outputs(sh, ir_var_in); demote_shader_inputs_and_outputs(sh, ir_var_inout); demote_shader_inputs_and_outputs(sh, ir_var_out); /* Eliminate code that is now dead due to unused geometry outputs being * demoted. */ while (do_dead_code(prog->_LinkedShaders[MESA_SHADER_GEOMETRY]->ir, false)) ; } if (prog->_LinkedShaders[MESA_SHADER_FRAGMENT] != NULL) { gl_shader *const sh = prog->_LinkedShaders[MESA_SHADER_FRAGMENT]; demote_shader_inputs_and_outputs(sh, ir_var_in); /* Eliminate code that is now dead due to unused fragment inputs being * demoted. This shouldn't actually do anything other than remove * declarations of the (now unused) global variables. */ while (do_dead_code(prog->_LinkedShaders[MESA_SHADER_FRAGMENT]->ir, false)) ; } update_array_sizes(prog); link_assign_uniform_locations(prog); store_fragdepth_layout(prog); if (!check_resources(ctx, prog)) goto done; /* OpenGL ES requires that a vertex shader and a fragment shader both be * present in a linked program. By checking for use of shading language * version 1.00, we also catch the GL_ARB_ES2_compatibility case. */ if (!prog->InternalSeparateShader && (ctx->API == API_OPENGLES2 || prog->Version == 100)) { if (prog->_LinkedShaders[MESA_SHADER_VERTEX] == NULL) { linker_error(prog, "program lacks a vertex shader\n"); } else if (prog->_LinkedShaders[MESA_SHADER_FRAGMENT] == NULL) { linker_error(prog, "program lacks a fragment shader\n"); } } /* FINISHME: Assign fragment shader output locations. */ done: free(vert_shader_list); for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) { if (prog->_LinkedShaders[i] == NULL) continue; /* Retain any live IR, but trash the rest. */ reparent_ir(prog->_LinkedShaders[i]->ir, prog->_LinkedShaders[i]->ir); /* The symbol table in the linked shaders may contain references to * variables that were removed (e.g., unused uniforms). Since it may * contain junk, there is no possible valid use. Delete it and set the * pointer to NULL. */ delete prog->_LinkedShaders[i]->symbols; prog->_LinkedShaders[i]->symbols = NULL; } ralloc_free(mem_ctx); }