/* * 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->get_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(); } 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 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; 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; } 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(); } 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() || ((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; } /** * 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) { 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; } } v; v.run(linked->ir); } return linked; } struct uniform_node { exec_node link; struct gl_uniform *u; unsigned slots; }; /** * 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. */ } } } } static void add_uniform(void *mem_ctx, exec_list *uniforms, struct hash_table *ht, const char *name, const glsl_type *type, GLenum shader_type, unsigned *next_shader_pos, unsigned *total_uniforms) { if (type->is_record()) { for (unsigned int i = 0; i < type->length; i++) { const glsl_type *field_type = type->fields.structure[i].type; char *field_name = ralloc_asprintf(mem_ctx, "%s.%s", name, type->fields.structure[i].name); add_uniform(mem_ctx, uniforms, ht, field_name, field_type, shader_type, next_shader_pos, total_uniforms); } } else { uniform_node *n = (uniform_node *) hash_table_find(ht, name); unsigned int vec4_slots; const glsl_type *array_elem_type = NULL; if (type->is_array()) { array_elem_type = type->fields.array; /* Array of structures. */ if (array_elem_type->is_record()) { for (unsigned int i = 0; i < type->length; i++) { char *elem_name = ralloc_asprintf(mem_ctx, "%s[%d]", name, i); add_uniform(mem_ctx, uniforms, ht, elem_name, array_elem_type, shader_type, next_shader_pos, total_uniforms); } return; } } /* Fix the storage size of samplers at 1 vec4 each. Be sure to pad out * vectors to vec4 slots. */ if (type->is_array()) { if (array_elem_type->is_sampler()) vec4_slots = type->length; else vec4_slots = type->length * array_elem_type->matrix_columns; } else if (type->is_sampler()) { vec4_slots = 1; } else { vec4_slots = type->matrix_columns; } if (n == NULL) { n = (uniform_node *) calloc(1, sizeof(struct uniform_node)); n->u = (gl_uniform *) calloc(1, sizeof(struct gl_uniform)); n->slots = vec4_slots; n->u->Name = strdup(name); n->u->Type = type; n->u->VertPos = -1; n->u->FragPos = -1; n->u->GeomPos = -1; (*total_uniforms)++; hash_table_insert(ht, n, name); uniforms->push_tail(& n->link); } switch (shader_type) { case GL_VERTEX_SHADER: n->u->VertPos = *next_shader_pos; break; case GL_FRAGMENT_SHADER: n->u->FragPos = *next_shader_pos; break; case GL_GEOMETRY_SHADER: n->u->GeomPos = *next_shader_pos; break; } (*next_shader_pos) += vec4_slots; } } void assign_uniform_locations(struct gl_shader_program *prog) { /* */ exec_list uniforms; unsigned total_uniforms = 0; hash_table *ht = hash_table_ctor(32, hash_table_string_hash, hash_table_string_compare); void *mem_ctx = ralloc_context(NULL); for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) { if (prog->_LinkedShaders[i] == NULL) continue; unsigned next_position = 0; foreach_list(node, prog->_LinkedShaders[i]->ir) { ir_variable *const var = ((ir_instruction *) node)->as_variable(); if ((var == NULL) || (var->mode != ir_var_uniform)) continue; if (strncmp(var->name, "gl_", 3) == 0) { /* At the moment, we don't allocate uniform locations for * builtin uniforms. It's permitted by spec, and we'll * likely switch to doing that at some point, but not yet. */ continue; } var->location = next_position; add_uniform(mem_ctx, &uniforms, ht, var->name, var->type, prog->_LinkedShaders[i]->Type, &next_position, &total_uniforms); } } ralloc_free(mem_ctx); gl_uniform_list *ul = (gl_uniform_list *) calloc(1, sizeof(gl_uniform_list)); ul->Size = total_uniforms; ul->NumUniforms = total_uniforms; ul->Uniforms = (gl_uniform *) calloc(total_uniforms, sizeof(gl_uniform)); unsigned idx = 0; uniform_node *next; for (uniform_node *node = (uniform_node *) uniforms.head ; node->link.next != NULL ; node = next) { next = (uniform_node *) node->link.next; node->link.remove(); memcpy(&ul->Uniforms[idx], node->u, sizeof(gl_uniform)); idx++; free(node->u); free(node); } hash_table_dtor(ht); prog->Uniforms = ul; } /** * 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. * * \bug * Locations set via \c glBindFragDataLocation are not currently supported. * Only locations assigned automatically by the linker, explicitly set by a * layout qualifier, or explicitly set by a built-in variable (e.g., \c * gl_FragColor) are supported for fragment shaders. */ 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. * * 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; } } /* 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) { /* 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) { linker_error(prog, "insufficient contiguous attribute locations " "available for vertex shader input `%s'", var->name); 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 attribute 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; } } } bool assign_varying_locations(struct gl_context *ctx, struct gl_shader_program *prog, gl_shader *producer, gl_shader *consumer) { /* 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); 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) || (output_var->location != -1)) continue; ir_variable *const input_var = consumer->symbols->get_variable(output_var->name); if ((input_var == NULL) || (input_var->mode != ir_var_in)) continue; assert(input_var->location == -1); output_var->location = output_index; input_var->location = input_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; } } unsigned varying_vectors = 0; 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) { linker_error(prog, "shader uses too many varying vectors " "(%u > %u)\n", varying_vectors, ctx->Const.MaxVarying); return false; } } else { const unsigned float_components = varying_vectors * 4; if (float_components > ctx->Const.MaxVarying * 4) { linker_error(prog, "shader uses too many varying components " "(%u > %u)\n", float_components, ctx->Const.MaxVarying * 4); return false; } } return true; } void link_shaders(struct gl_context *ctx, struct gl_shader_program *prog) { 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 <= 130); 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; } /* 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); while (do_common_optimization(prog->_LinkedShaders[i]->ir, true, false, 32)) ; } /* 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, ctx->Const.MaxDrawBuffers)) { goto done; } unsigned prev; for (prev = 0; prev < MESA_SHADER_TYPES; prev++) { if (prog->_LinkedShaders[prev] != NULL) break; } 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])) { goto done; } prev = i; } 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); /* 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); }