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26 * GLSL linker implementation
28 * Given a set of shaders that are to be linked to generate a final program,
29 * there are three distinct stages.
31 * In the first stage shaders are partitioned into groups based on the shader
32 * type. All shaders of a particular type (e.g., vertex shaders) are linked
35 * - Undefined references in each shader are resolve to definitions in
37 * - Types and qualifiers of uniforms, outputs, and global variables defined
38 * in multiple shaders with the same name are verified to be the same.
39 * - Initializers for uniforms and global variables defined
40 * in multiple shaders with the same name are verified to be the same.
42 * The result, in the terminology of the GLSL spec, is a set of shader
43 * executables for each processing unit.
45 * After the first stage is complete, a series of semantic checks are performed
46 * on each of the shader executables.
48 * - Each shader executable must define a \c main function.
49 * - Each vertex shader executable must write to \c gl_Position.
50 * - Each fragment shader executable must write to either \c gl_FragData or
53 * In the final stage individual shader executables are linked to create a
54 * complete exectuable.
56 * - Types of uniforms defined in multiple shader stages with the same name
57 * are verified to be the same.
58 * - Initializers for uniforms defined in multiple shader stages with the
59 * same name are verified to be the same.
60 * - Types and qualifiers of outputs defined in one stage are verified to
61 * be the same as the types and qualifiers of inputs defined with the same
62 * name in a later stage.
64 * \author Ian Romanick <ian.d.romanick@intel.com>
67 #include "main/core.h"
68 #include "glsl_symbol_table.h"
71 #include "program/hash_table.h"
73 #include "ir_optimization.h"
76 #include "main/shaderobj.h"
80 * Visitor that determines whether or not a variable is ever written.
82 class find_assignment_visitor : public ir_hierarchical_visitor {
84 find_assignment_visitor(const char *name)
85 : name(name), found(false)
90 virtual ir_visitor_status visit_enter(ir_assignment *ir)
92 ir_variable *const var = ir->lhs->variable_referenced();
94 if (strcmp(name, var->name) == 0) {
99 return visit_continue_with_parent;
102 virtual ir_visitor_status visit_enter(ir_call *ir)
104 exec_list_iterator sig_iter = ir->get_callee()->parameters.iterator();
105 foreach_iter(exec_list_iterator, iter, *ir) {
106 ir_rvalue *param_rval = (ir_rvalue *)iter.get();
107 ir_variable *sig_param = (ir_variable *)sig_iter.get();
109 if (sig_param->mode == ir_var_out ||
110 sig_param->mode == ir_var_inout) {
111 ir_variable *var = param_rval->variable_referenced();
112 if (var && strcmp(name, var->name) == 0) {
120 return visit_continue_with_parent;
123 bool variable_found()
129 const char *name; /**< Find writes to a variable with this name. */
130 bool found; /**< Was a write to the variable found? */
135 * Visitor that determines whether or not a variable is ever read.
137 class find_deref_visitor : public ir_hierarchical_visitor {
139 find_deref_visitor(const char *name)
140 : name(name), found(false)
145 virtual ir_visitor_status visit(ir_dereference_variable *ir)
147 if (strcmp(this->name, ir->var->name) == 0) {
152 return visit_continue;
155 bool variable_found() const
161 const char *name; /**< Find writes to a variable with this name. */
162 bool found; /**< Was a write to the variable found? */
167 linker_error(gl_shader_program *prog, const char *fmt, ...)
171 ralloc_strcat(&prog->InfoLog, "error: ");
173 ralloc_vasprintf_append(&prog->InfoLog, fmt, ap);
176 prog->LinkStatus = false;
181 linker_warning(gl_shader_program *prog, const char *fmt, ...)
185 ralloc_strcat(&prog->InfoLog, "error: ");
187 ralloc_vasprintf_append(&prog->InfoLog, fmt, ap);
194 invalidate_variable_locations(gl_shader *sh, enum ir_variable_mode mode,
197 foreach_list(node, sh->ir) {
198 ir_variable *const var = ((ir_instruction *) node)->as_variable();
200 if ((var == NULL) || (var->mode != (unsigned) mode))
203 /* Only assign locations for generic attributes / varyings / etc.
205 if ((var->location >= generic_base) && !var->explicit_location)
212 * Determine the number of attribute slots required for a particular type
214 * This code is here because it implements the language rules of a specific
215 * GLSL version. Since it's a property of the language and not a property of
216 * types in general, it doesn't really belong in glsl_type.
219 count_attribute_slots(const glsl_type *t)
221 /* From page 31 (page 37 of the PDF) of the GLSL 1.50 spec:
223 * "A scalar input counts the same amount against this limit as a vec4,
224 * so applications may want to consider packing groups of four
225 * unrelated float inputs together into a vector to better utilize the
226 * capabilities of the underlying hardware. A matrix input will use up
227 * multiple locations. The number of locations used will equal the
228 * number of columns in the matrix."
230 * The spec does not explicitly say how arrays are counted. However, it
231 * should be safe to assume the total number of slots consumed by an array
232 * is the number of entries in the array multiplied by the number of slots
233 * consumed by a single element of the array.
237 return t->array_size() * count_attribute_slots(t->element_type());
240 return t->matrix_columns;
247 * Verify that a vertex shader executable meets all semantic requirements
249 * \param shader Vertex shader executable to be verified
252 validate_vertex_shader_executable(struct gl_shader_program *prog,
253 struct gl_shader *shader)
258 find_assignment_visitor find("gl_Position");
259 find.run(shader->ir);
260 if (!find.variable_found()) {
261 linker_error(prog, "vertex shader does not write to `gl_Position'\n");
265 if (prog->Version >= 130) {
266 /* From section 7.1 (Vertex Shader Special Variables) of the
269 * "It is an error for a shader to statically write both
270 * gl_ClipVertex and gl_ClipDistance."
272 find_assignment_visitor clip_vertex("gl_ClipVertex");
273 find_assignment_visitor clip_distance("gl_ClipDistance");
275 clip_vertex.run(shader->ir);
276 clip_distance.run(shader->ir);
277 if (clip_vertex.variable_found() && clip_distance.variable_found()) {
278 linker_error(prog, "vertex shader writes to both `gl_ClipVertex' "
279 "and `gl_ClipDistance'\n");
289 * Verify that a fragment shader executable meets all semantic requirements
291 * \param shader Fragment shader executable to be verified
294 validate_fragment_shader_executable(struct gl_shader_program *prog,
295 struct gl_shader *shader)
300 find_assignment_visitor frag_color("gl_FragColor");
301 find_assignment_visitor frag_data("gl_FragData");
303 frag_color.run(shader->ir);
304 frag_data.run(shader->ir);
306 if (frag_color.variable_found() && frag_data.variable_found()) {
307 linker_error(prog, "fragment shader writes to both "
308 "`gl_FragColor' and `gl_FragData'\n");
317 * Generate a string describing the mode of a variable
320 mode_string(const ir_variable *var)
324 return (var->read_only) ? "global constant" : "global variable";
326 case ir_var_uniform: return "uniform";
327 case ir_var_in: return "shader input";
328 case ir_var_out: return "shader output";
329 case ir_var_inout: return "shader inout";
331 case ir_var_const_in:
332 case ir_var_temporary:
334 assert(!"Should not get here.");
335 return "invalid variable";
341 * Perform validation of global variables used across multiple shaders
344 cross_validate_globals(struct gl_shader_program *prog,
345 struct gl_shader **shader_list,
346 unsigned num_shaders,
349 /* Examine all of the uniforms in all of the shaders and cross validate
352 glsl_symbol_table variables;
353 for (unsigned i = 0; i < num_shaders; i++) {
354 if (shader_list[i] == NULL)
357 foreach_list(node, shader_list[i]->ir) {
358 ir_variable *const var = ((ir_instruction *) node)->as_variable();
363 if (uniforms_only && (var->mode != ir_var_uniform))
366 /* Don't cross validate temporaries that are at global scope. These
367 * will eventually get pulled into the shaders 'main'.
369 if (var->mode == ir_var_temporary)
372 /* If a global with this name has already been seen, verify that the
373 * new instance has the same type. In addition, if the globals have
374 * initializers, the values of the initializers must be the same.
376 ir_variable *const existing = variables.get_variable(var->name);
377 if (existing != NULL) {
378 if (var->type != existing->type) {
379 /* Consider the types to be "the same" if both types are arrays
380 * of the same type and one of the arrays is implicitly sized.
381 * In addition, set the type of the linked variable to the
382 * explicitly sized array.
384 if (var->type->is_array()
385 && existing->type->is_array()
386 && (var->type->fields.array == existing->type->fields.array)
387 && ((var->type->length == 0)
388 || (existing->type->length == 0))) {
389 if (var->type->length != 0) {
390 existing->type = var->type;
393 linker_error(prog, "%s `%s' declared as type "
394 "`%s' and type `%s'\n",
396 var->name, var->type->name,
397 existing->type->name);
402 if (var->explicit_location) {
403 if (existing->explicit_location
404 && (var->location != existing->location)) {
405 linker_error(prog, "explicit locations for %s "
406 "`%s' have differing values\n",
407 mode_string(var), var->name);
411 existing->location = var->location;
412 existing->explicit_location = true;
415 /* Validate layout qualifiers for gl_FragDepth.
417 * From the AMD/ARB_conservative_depth specs:
418 * "If gl_FragDepth is redeclared in any fragment shader in
419 * a program, it must be redeclared in all fragment shaders in that
420 * program that have static assignments to gl_FragDepth. All
421 * redeclarations of gl_FragDepth in all fragment shaders in
422 * a single program must have the same set of qualifiers."
424 if (strcmp(var->name, "gl_FragDepth") == 0) {
425 bool layout_declared = var->depth_layout != ir_depth_layout_none;
426 bool layout_differs = var->depth_layout != existing->depth_layout;
427 if (layout_declared && layout_differs) {
429 "All redeclarations of gl_FragDepth in all fragment shaders "
430 "in a single program must have the same set of qualifiers.");
432 if (var->used && layout_differs) {
434 "If gl_FragDepth is redeclared with a layout qualifier in"
435 "any fragment shader, it must be redeclared with the same"
436 "layout qualifier in all fragment shaders that have"
437 "assignments to gl_FragDepth");
441 /* FINISHME: Handle non-constant initializers.
443 if (var->constant_value != NULL) {
444 if (existing->constant_value != NULL) {
445 if (!var->constant_value->has_value(existing->constant_value)) {
446 linker_error(prog, "initializers for %s "
447 "`%s' have differing values\n",
448 mode_string(var), var->name);
452 /* If the first-seen instance of a particular uniform did not
453 * have an initializer but a later instance does, copy the
454 * initializer to the version stored in the symbol table.
456 /* FINISHME: This is wrong. The constant_value field should
457 * FINISHME: not be modified! Imagine a case where a shader
458 * FINISHME: without an initializer is linked in two different
459 * FINISHME: programs with shaders that have differing
460 * FINISHME: initializers. Linking with the first will
461 * FINISHME: modify the shader, and linking with the second
462 * FINISHME: will fail.
464 existing->constant_value =
465 var->constant_value->clone(ralloc_parent(existing), NULL);
468 if (existing->invariant != var->invariant) {
469 linker_error(prog, "declarations for %s `%s' have "
470 "mismatching invariant qualifiers\n",
471 mode_string(var), var->name);
474 if (existing->centroid != var->centroid) {
475 linker_error(prog, "declarations for %s `%s' have "
476 "mismatching centroid qualifiers\n",
477 mode_string(var), var->name);
481 variables.add_variable(var);
490 * Perform validation of uniforms used across multiple shader stages
493 cross_validate_uniforms(struct gl_shader_program *prog)
495 return cross_validate_globals(prog, prog->_LinkedShaders,
496 MESA_SHADER_TYPES, true);
501 * Validate that outputs from one stage match inputs of another
504 cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
505 gl_shader *producer, gl_shader *consumer)
507 glsl_symbol_table parameters;
508 /* FINISHME: Figure these out dynamically. */
509 const char *const producer_stage = "vertex";
510 const char *const consumer_stage = "fragment";
512 /* Find all shader outputs in the "producer" stage.
514 foreach_list(node, producer->ir) {
515 ir_variable *const var = ((ir_instruction *) node)->as_variable();
517 /* FINISHME: For geometry shaders, this should also look for inout
518 * FINISHME: variables.
520 if ((var == NULL) || (var->mode != ir_var_out))
523 parameters.add_variable(var);
527 /* Find all shader inputs in the "consumer" stage. Any variables that have
528 * matching outputs already in the symbol table must have the same type and
531 foreach_list(node, consumer->ir) {
532 ir_variable *const input = ((ir_instruction *) node)->as_variable();
534 /* FINISHME: For geometry shaders, this should also look for inout
535 * FINISHME: variables.
537 if ((input == NULL) || (input->mode != ir_var_in))
540 ir_variable *const output = parameters.get_variable(input->name);
541 if (output != NULL) {
542 /* Check that the types match between stages.
544 if (input->type != output->type) {
545 /* There is a bit of a special case for gl_TexCoord. This
546 * built-in is unsized by default. Applications that variable
547 * access it must redeclare it with a size. There is some
548 * language in the GLSL spec that implies the fragment shader
549 * and vertex shader do not have to agree on this size. Other
550 * driver behave this way, and one or two applications seem to
553 * Neither declaration needs to be modified here because the array
554 * sizes are fixed later when update_array_sizes is called.
556 * From page 48 (page 54 of the PDF) of the GLSL 1.10 spec:
558 * "Unlike user-defined varying variables, the built-in
559 * varying variables don't have a strict one-to-one
560 * correspondence between the vertex language and the
561 * fragment language."
563 if (!output->type->is_array()
564 || (strncmp("gl_", output->name, 3) != 0)) {
566 "%s shader output `%s' declared as type `%s', "
567 "but %s shader input declared as type `%s'\n",
568 producer_stage, output->name,
570 consumer_stage, input->type->name);
575 /* Check that all of the qualifiers match between stages.
577 if (input->centroid != output->centroid) {
579 "%s shader output `%s' %s centroid qualifier, "
580 "but %s shader input %s centroid qualifier\n",
583 (output->centroid) ? "has" : "lacks",
585 (input->centroid) ? "has" : "lacks");
589 if (input->invariant != output->invariant) {
591 "%s shader output `%s' %s invariant qualifier, "
592 "but %s shader input %s invariant qualifier\n",
595 (output->invariant) ? "has" : "lacks",
597 (input->invariant) ? "has" : "lacks");
601 if (input->interpolation != output->interpolation) {
603 "%s shader output `%s' specifies %s "
604 "interpolation qualifier, "
605 "but %s shader input specifies %s "
606 "interpolation qualifier\n",
609 output->interpolation_string(),
611 input->interpolation_string());
622 * Populates a shaders symbol table with all global declarations
625 populate_symbol_table(gl_shader *sh)
627 sh->symbols = new(sh) glsl_symbol_table;
629 foreach_list(node, sh->ir) {
630 ir_instruction *const inst = (ir_instruction *) node;
634 if ((func = inst->as_function()) != NULL) {
635 sh->symbols->add_function(func);
636 } else if ((var = inst->as_variable()) != NULL) {
637 sh->symbols->add_variable(var);
644 * Remap variables referenced in an instruction tree
646 * This is used when instruction trees are cloned from one shader and placed in
647 * another. These trees will contain references to \c ir_variable nodes that
648 * do not exist in the target shader. This function finds these \c ir_variable
649 * references and replaces the references with matching variables in the target
652 * If there is no matching variable in the target shader, a clone of the
653 * \c ir_variable is made and added to the target shader. The new variable is
654 * added to \b both the instruction stream and the symbol table.
656 * \param inst IR tree that is to be processed.
657 * \param symbols Symbol table containing global scope symbols in the
659 * \param instructions Instruction stream where new variable declarations
663 remap_variables(ir_instruction *inst, struct gl_shader *target,
666 class remap_visitor : public ir_hierarchical_visitor {
668 remap_visitor(struct gl_shader *target,
671 this->target = target;
672 this->symbols = target->symbols;
673 this->instructions = target->ir;
677 virtual ir_visitor_status visit(ir_dereference_variable *ir)
679 if (ir->var->mode == ir_var_temporary) {
680 ir_variable *var = (ir_variable *) hash_table_find(temps, ir->var);
684 return visit_continue;
687 ir_variable *const existing =
688 this->symbols->get_variable(ir->var->name);
689 if (existing != NULL)
692 ir_variable *copy = ir->var->clone(this->target, NULL);
694 this->symbols->add_variable(copy);
695 this->instructions->push_head(copy);
699 return visit_continue;
703 struct gl_shader *target;
704 glsl_symbol_table *symbols;
705 exec_list *instructions;
709 remap_visitor v(target, temps);
716 * Move non-declarations from one instruction stream to another
718 * The intended usage pattern of this function is to pass the pointer to the
719 * head sentinel of a list (i.e., a pointer to the list cast to an \c exec_node
720 * pointer) for \c last and \c false for \c make_copies on the first
721 * call. Successive calls pass the return value of the previous call for
722 * \c last and \c true for \c make_copies.
724 * \param instructions Source instruction stream
725 * \param last Instruction after which new instructions should be
726 * inserted in the target instruction stream
727 * \param make_copies Flag selecting whether instructions in \c instructions
728 * should be copied (via \c ir_instruction::clone) into the
729 * target list or moved.
732 * The new "last" instruction in the target instruction stream. This pointer
733 * is suitable for use as the \c last parameter of a later call to this
737 move_non_declarations(exec_list *instructions, exec_node *last,
738 bool make_copies, gl_shader *target)
740 hash_table *temps = NULL;
743 temps = hash_table_ctor(0, hash_table_pointer_hash,
744 hash_table_pointer_compare);
746 foreach_list_safe(node, instructions) {
747 ir_instruction *inst = (ir_instruction *) node;
749 if (inst->as_function())
752 ir_variable *var = inst->as_variable();
753 if ((var != NULL) && (var->mode != ir_var_temporary))
756 assert(inst->as_assignment()
757 || ((var != NULL) && (var->mode == ir_var_temporary)));
760 inst = inst->clone(target, NULL);
763 hash_table_insert(temps, inst, var);
765 remap_variables(inst, target, temps);
770 last->insert_after(inst);
775 hash_table_dtor(temps);
781 * Get the function signature for main from a shader
783 static ir_function_signature *
784 get_main_function_signature(gl_shader *sh)
786 ir_function *const f = sh->symbols->get_function("main");
788 exec_list void_parameters;
790 /* Look for the 'void main()' signature and ensure that it's defined.
791 * This keeps the linker from accidentally pick a shader that just
792 * contains a prototype for main.
794 * We don't have to check for multiple definitions of main (in multiple
795 * shaders) because that would have already been caught above.
797 ir_function_signature *sig = f->matching_signature(&void_parameters);
798 if ((sig != NULL) && sig->is_defined) {
808 * Combine a group of shaders for a single stage to generate a linked shader
811 * If this function is supplied a single shader, it is cloned, and the new
812 * shader is returned.
814 static struct gl_shader *
815 link_intrastage_shaders(void *mem_ctx,
816 struct gl_context *ctx,
817 struct gl_shader_program *prog,
818 struct gl_shader **shader_list,
819 unsigned num_shaders)
821 /* Check that global variables defined in multiple shaders are consistent.
823 if (!cross_validate_globals(prog, shader_list, num_shaders, false))
826 /* Check that there is only a single definition of each function signature
827 * across all shaders.
829 for (unsigned i = 0; i < (num_shaders - 1); i++) {
830 foreach_list(node, shader_list[i]->ir) {
831 ir_function *const f = ((ir_instruction *) node)->as_function();
836 for (unsigned j = i + 1; j < num_shaders; j++) {
837 ir_function *const other =
838 shader_list[j]->symbols->get_function(f->name);
840 /* If the other shader has no function (and therefore no function
841 * signatures) with the same name, skip to the next shader.
846 foreach_iter (exec_list_iterator, iter, *f) {
847 ir_function_signature *sig =
848 (ir_function_signature *) iter.get();
850 if (!sig->is_defined || sig->is_builtin)
853 ir_function_signature *other_sig =
854 other->exact_matching_signature(& sig->parameters);
856 if ((other_sig != NULL) && other_sig->is_defined
857 && !other_sig->is_builtin) {
858 linker_error(prog, "function `%s' is multiply defined",
867 /* Find the shader that defines main, and make a clone of it.
869 * Starting with the clone, search for undefined references. If one is
870 * found, find the shader that defines it. Clone the reference and add
871 * it to the shader. Repeat until there are no undefined references or
872 * until a reference cannot be resolved.
874 gl_shader *main = NULL;
875 for (unsigned i = 0; i < num_shaders; i++) {
876 if (get_main_function_signature(shader_list[i]) != NULL) {
877 main = shader_list[i];
883 linker_error(prog, "%s shader lacks `main'\n",
884 (shader_list[0]->Type == GL_VERTEX_SHADER)
885 ? "vertex" : "fragment");
889 gl_shader *linked = ctx->Driver.NewShader(NULL, 0, main->Type);
890 linked->ir = new(linked) exec_list;
891 clone_ir_list(mem_ctx, linked->ir, main->ir);
893 populate_symbol_table(linked);
895 /* The a pointer to the main function in the final linked shader (i.e., the
896 * copy of the original shader that contained the main function).
898 ir_function_signature *const main_sig = get_main_function_signature(linked);
900 /* Move any instructions other than variable declarations or function
901 * declarations into main.
903 exec_node *insertion_point =
904 move_non_declarations(linked->ir, (exec_node *) &main_sig->body, false,
907 for (unsigned i = 0; i < num_shaders; i++) {
908 if (shader_list[i] == main)
911 insertion_point = move_non_declarations(shader_list[i]->ir,
912 insertion_point, true, linked);
915 /* Resolve initializers for global variables in the linked shader.
917 unsigned num_linking_shaders = num_shaders;
918 for (unsigned i = 0; i < num_shaders; i++)
919 num_linking_shaders += shader_list[i]->num_builtins_to_link;
921 gl_shader **linking_shaders =
922 (gl_shader **) calloc(num_linking_shaders, sizeof(gl_shader *));
924 memcpy(linking_shaders, shader_list,
925 sizeof(linking_shaders[0]) * num_shaders);
927 unsigned idx = num_shaders;
928 for (unsigned i = 0; i < num_shaders; i++) {
929 memcpy(&linking_shaders[idx], shader_list[i]->builtins_to_link,
930 sizeof(linking_shaders[0]) * shader_list[i]->num_builtins_to_link);
931 idx += shader_list[i]->num_builtins_to_link;
934 assert(idx == num_linking_shaders);
936 if (!link_function_calls(prog, linked, linking_shaders,
937 num_linking_shaders)) {
938 ctx->Driver.DeleteShader(ctx, linked);
942 free(linking_shaders);
945 /* At this point linked should contain all of the linked IR, so
946 * validate it to make sure nothing went wrong.
949 validate_ir_tree(linked->ir);
952 /* Make a pass over all variable declarations to ensure that arrays with
953 * unspecified sizes have a size specified. The size is inferred from the
954 * max_array_access field.
956 if (linked != NULL) {
957 class array_sizing_visitor : public ir_hierarchical_visitor {
959 virtual ir_visitor_status visit(ir_variable *var)
961 if (var->type->is_array() && (var->type->length == 0)) {
962 const glsl_type *type =
963 glsl_type::get_array_instance(var->type->fields.array,
964 var->max_array_access + 1);
966 assert(type != NULL);
970 return visit_continue;
981 struct uniform_node {
983 struct gl_uniform *u;
988 * Update the sizes of linked shader uniform arrays to the maximum
991 * From page 81 (page 95 of the PDF) of the OpenGL 2.1 spec:
993 * If one or more elements of an array are active,
994 * GetActiveUniform will return the name of the array in name,
995 * subject to the restrictions listed above. The type of the array
996 * is returned in type. The size parameter contains the highest
997 * array element index used, plus one. The compiler or linker
998 * determines the highest index used. There will be only one
999 * active uniform reported by the GL per uniform array.
1003 update_array_sizes(struct gl_shader_program *prog)
1005 for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
1006 if (prog->_LinkedShaders[i] == NULL)
1009 foreach_list(node, prog->_LinkedShaders[i]->ir) {
1010 ir_variable *const var = ((ir_instruction *) node)->as_variable();
1012 if ((var == NULL) || (var->mode != ir_var_uniform &&
1013 var->mode != ir_var_in &&
1014 var->mode != ir_var_out) ||
1015 !var->type->is_array())
1018 unsigned int size = var->max_array_access;
1019 for (unsigned j = 0; j < MESA_SHADER_TYPES; j++) {
1020 if (prog->_LinkedShaders[j] == NULL)
1023 foreach_list(node2, prog->_LinkedShaders[j]->ir) {
1024 ir_variable *other_var = ((ir_instruction *) node2)->as_variable();
1028 if (strcmp(var->name, other_var->name) == 0 &&
1029 other_var->max_array_access > size) {
1030 size = other_var->max_array_access;
1035 if (size + 1 != var->type->fields.array->length) {
1036 /* If this is a built-in uniform (i.e., it's backed by some
1037 * fixed-function state), adjust the number of state slots to
1038 * match the new array size. The number of slots per array entry
1039 * is not known. It seems safe to assume that the total number of
1040 * slots is an integer multiple of the number of array elements.
1041 * Determine the number of slots per array element by dividing by
1042 * the old (total) size.
1044 if (var->num_state_slots > 0) {
1045 var->num_state_slots = (size + 1)
1046 * (var->num_state_slots / var->type->length);
1049 var->type = glsl_type::get_array_instance(var->type->fields.array,
1051 /* FINISHME: We should update the types of array
1052 * dereferences of this variable now.
1060 add_uniform(void *mem_ctx, exec_list *uniforms, struct hash_table *ht,
1061 const char *name, const glsl_type *type, GLenum shader_type,
1062 unsigned *next_shader_pos, unsigned *total_uniforms)
1064 if (type->is_record()) {
1065 for (unsigned int i = 0; i < type->length; i++) {
1066 const glsl_type *field_type = type->fields.structure[i].type;
1067 char *field_name = ralloc_asprintf(mem_ctx, "%s.%s", name,
1068 type->fields.structure[i].name);
1070 add_uniform(mem_ctx, uniforms, ht, field_name, field_type,
1071 shader_type, next_shader_pos, total_uniforms);
1074 uniform_node *n = (uniform_node *) hash_table_find(ht, name);
1075 unsigned int vec4_slots;
1076 const glsl_type *array_elem_type = NULL;
1078 if (type->is_array()) {
1079 array_elem_type = type->fields.array;
1080 /* Array of structures. */
1081 if (array_elem_type->is_record()) {
1082 for (unsigned int i = 0; i < type->length; i++) {
1083 char *elem_name = ralloc_asprintf(mem_ctx, "%s[%d]", name, i);
1084 add_uniform(mem_ctx, uniforms, ht, elem_name, array_elem_type,
1085 shader_type, next_shader_pos, total_uniforms);
1091 /* Fix the storage size of samplers at 1 vec4 each. Be sure to pad out
1092 * vectors to vec4 slots.
1094 if (type->is_array()) {
1095 if (array_elem_type->is_sampler())
1096 vec4_slots = type->length;
1098 vec4_slots = type->length * array_elem_type->matrix_columns;
1099 } else if (type->is_sampler()) {
1102 vec4_slots = type->matrix_columns;
1106 n = (uniform_node *) calloc(1, sizeof(struct uniform_node));
1107 n->u = (gl_uniform *) calloc(1, sizeof(struct gl_uniform));
1108 n->slots = vec4_slots;
1110 n->u->Name = strdup(name);
1115 (*total_uniforms)++;
1117 hash_table_insert(ht, n, name);
1118 uniforms->push_tail(& n->link);
1121 switch (shader_type) {
1122 case GL_VERTEX_SHADER:
1123 n->u->VertPos = *next_shader_pos;
1125 case GL_FRAGMENT_SHADER:
1126 n->u->FragPos = *next_shader_pos;
1128 case GL_GEOMETRY_SHADER:
1129 n->u->GeomPos = *next_shader_pos;
1133 (*next_shader_pos) += vec4_slots;
1138 assign_uniform_locations(struct gl_shader_program *prog)
1142 unsigned total_uniforms = 0;
1143 hash_table *ht = hash_table_ctor(32, hash_table_string_hash,
1144 hash_table_string_compare);
1145 void *mem_ctx = ralloc_context(NULL);
1147 for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
1148 if (prog->_LinkedShaders[i] == NULL)
1151 unsigned next_position = 0;
1153 foreach_list(node, prog->_LinkedShaders[i]->ir) {
1154 ir_variable *const var = ((ir_instruction *) node)->as_variable();
1156 if ((var == NULL) || (var->mode != ir_var_uniform))
1159 if (strncmp(var->name, "gl_", 3) == 0) {
1160 /* At the moment, we don't allocate uniform locations for
1161 * builtin uniforms. It's permitted by spec, and we'll
1162 * likely switch to doing that at some point, but not yet.
1167 var->location = next_position;
1168 add_uniform(mem_ctx, &uniforms, ht, var->name, var->type,
1169 prog->_LinkedShaders[i]->Type,
1170 &next_position, &total_uniforms);
1174 ralloc_free(mem_ctx);
1176 gl_uniform_list *ul = (gl_uniform_list *)
1177 calloc(1, sizeof(gl_uniform_list));
1179 ul->Size = total_uniforms;
1180 ul->NumUniforms = total_uniforms;
1181 ul->Uniforms = (gl_uniform *) calloc(total_uniforms, sizeof(gl_uniform));
1185 for (uniform_node *node = (uniform_node *) uniforms.head
1186 ; node->link.next != NULL
1188 next = (uniform_node *) node->link.next;
1190 node->link.remove();
1191 memcpy(&ul->Uniforms[idx], node->u, sizeof(gl_uniform));
1198 hash_table_dtor(ht);
1200 prog->Uniforms = ul;
1205 * Find a contiguous set of available bits in a bitmask.
1207 * \param used_mask Bits representing used (1) and unused (0) locations
1208 * \param needed_count Number of contiguous bits needed.
1211 * Base location of the available bits on success or -1 on failure.
1214 find_available_slots(unsigned used_mask, unsigned needed_count)
1216 unsigned needed_mask = (1 << needed_count) - 1;
1217 const int max_bit_to_test = (8 * sizeof(used_mask)) - needed_count;
1219 /* The comparison to 32 is redundant, but without it GCC emits "warning:
1220 * cannot optimize possibly infinite loops" for the loop below.
1222 if ((needed_count == 0) || (max_bit_to_test < 0) || (max_bit_to_test > 32))
1225 for (int i = 0; i <= max_bit_to_test; i++) {
1226 if ((needed_mask & ~used_mask) == needed_mask)
1237 * Assign locations for either VS inputs for FS outputs
1239 * \param prog Shader program whose variables need locations assigned
1240 * \param target_index Selector for the program target to receive location
1241 * assignmnets. Must be either \c MESA_SHADER_VERTEX or
1242 * \c MESA_SHADER_FRAGMENT.
1243 * \param max_index Maximum number of generic locations. This corresponds
1244 * to either the maximum number of draw buffers or the
1245 * maximum number of generic attributes.
1248 * If locations are successfully assigned, true is returned. Otherwise an
1249 * error is emitted to the shader link log and false is returned.
1252 * Locations set via \c glBindFragDataLocation are not currently supported.
1253 * Only locations assigned automatically by the linker, explicitly set by a
1254 * layout qualifier, or explicitly set by a built-in variable (e.g., \c
1255 * gl_FragColor) are supported for fragment shaders.
1258 assign_attribute_or_color_locations(gl_shader_program *prog,
1259 unsigned target_index,
1262 /* Mark invalid locations as being used.
1264 unsigned used_locations = (max_index >= 32)
1265 ? ~0 : ~((1 << max_index) - 1);
1267 assert((target_index == MESA_SHADER_VERTEX)
1268 || (target_index == MESA_SHADER_FRAGMENT));
1270 gl_shader *const sh = prog->_LinkedShaders[target_index];
1274 /* Operate in a total of four passes.
1276 * 1. Invalidate the location assignments for all vertex shader inputs.
1278 * 2. Assign locations for inputs that have user-defined (via
1279 * glBindVertexAttribLocation) locations.
1281 * 3. Sort the attributes without assigned locations by number of slots
1282 * required in decreasing order. Fragmentation caused by attribute
1283 * locations assigned by the application may prevent large attributes
1284 * from having enough contiguous space.
1286 * 4. Assign locations to any inputs without assigned locations.
1289 const int generic_base = (target_index == MESA_SHADER_VERTEX)
1290 ? (int) VERT_ATTRIB_GENERIC0 : (int) FRAG_RESULT_DATA0;
1292 const enum ir_variable_mode direction =
1293 (target_index == MESA_SHADER_VERTEX) ? ir_var_in : ir_var_out;
1296 invalidate_variable_locations(sh, direction, generic_base);
1298 if ((target_index == MESA_SHADER_VERTEX) && (prog->Attributes != NULL)) {
1299 for (unsigned i = 0; i < prog->Attributes->NumParameters; i++) {
1300 ir_variable *const var =
1301 sh->symbols->get_variable(prog->Attributes->Parameters[i].Name);
1303 /* Note: attributes that occupy multiple slots, such as arrays or
1304 * matrices, may appear in the attrib array multiple times.
1306 if ((var == NULL) || (var->location != -1))
1309 /* From page 61 of the OpenGL 4.0 spec:
1311 * "LinkProgram will fail if the attribute bindings assigned by
1312 * BindAttribLocation do not leave not enough space to assign a
1313 * location for an active matrix attribute or an active attribute
1314 * array, both of which require multiple contiguous generic
1317 * Previous versions of the spec contain similar language but omit the
1318 * bit about attribute arrays.
1320 * Page 61 of the OpenGL 4.0 spec also says:
1322 * "It is possible for an application to bind more than one
1323 * attribute name to the same location. This is referred to as
1324 * aliasing. This will only work if only one of the aliased
1325 * attributes is active in the executable program, or if no path
1326 * through the shader consumes more than one attribute of a set
1327 * of attributes aliased to the same location. A link error can
1328 * occur if the linker determines that every path through the
1329 * shader consumes multiple aliased attributes, but
1330 * implementations are not required to generate an error in this
1333 * These two paragraphs are either somewhat contradictory, or I don't
1334 * fully understand one or both of them.
1336 /* FINISHME: The code as currently written does not support attribute
1337 * FINISHME: location aliasing (see comment above).
1339 const int attr = prog->Attributes->Parameters[i].StateIndexes[0];
1340 const unsigned slots = count_attribute_slots(var->type);
1342 /* Mask representing the contiguous slots that will be used by this
1345 const unsigned use_mask = (1 << slots) - 1;
1347 /* Generate a link error if the set of bits requested for this
1348 * attribute overlaps any previously allocated bits.
1350 if ((~(use_mask << attr) & used_locations) != used_locations) {
1352 "insufficient contiguous attribute locations "
1353 "available for vertex shader input `%s'",
1358 var->location = VERT_ATTRIB_GENERIC0 + attr;
1359 used_locations |= (use_mask << attr);
1363 /* Temporary storage for the set of attributes that need locations assigned.
1369 /* Used below in the call to qsort. */
1370 static int compare(const void *a, const void *b)
1372 const temp_attr *const l = (const temp_attr *) a;
1373 const temp_attr *const r = (const temp_attr *) b;
1375 /* Reversed because we want a descending order sort below. */
1376 return r->slots - l->slots;
1380 unsigned num_attr = 0;
1382 foreach_list(node, sh->ir) {
1383 ir_variable *const var = ((ir_instruction *) node)->as_variable();
1385 if ((var == NULL) || (var->mode != (unsigned) direction))
1388 if (var->explicit_location) {
1389 const unsigned slots = count_attribute_slots(var->type);
1390 const unsigned use_mask = (1 << slots) - 1;
1391 const int attr = var->location - generic_base;
1393 if ((var->location >= (int)(max_index + generic_base))
1394 || (var->location < 0)) {
1396 "invalid explicit location %d specified for `%s'\n",
1397 (var->location < 0) ? var->location : attr,
1400 } else if (var->location >= generic_base) {
1401 used_locations |= (use_mask << attr);
1405 /* The location was explicitly assigned, nothing to do here.
1407 if (var->location != -1)
1410 to_assign[num_attr].slots = count_attribute_slots(var->type);
1411 to_assign[num_attr].var = var;
1415 /* If all of the attributes were assigned locations by the application (or
1416 * are built-in attributes with fixed locations), return early. This should
1417 * be the common case.
1422 qsort(to_assign, num_attr, sizeof(to_assign[0]), temp_attr::compare);
1424 if (target_index == MESA_SHADER_VERTEX) {
1425 /* VERT_ATTRIB_GENERIC0 is a pseudo-alias for VERT_ATTRIB_POS. It can
1426 * only be explicitly assigned by via glBindAttribLocation. Mark it as
1427 * reserved to prevent it from being automatically allocated below.
1429 find_deref_visitor find("gl_Vertex");
1431 if (find.variable_found())
1432 used_locations |= (1 << 0);
1435 for (unsigned i = 0; i < num_attr; i++) {
1436 /* Mask representing the contiguous slots that will be used by this
1439 const unsigned use_mask = (1 << to_assign[i].slots) - 1;
1441 int location = find_available_slots(used_locations, to_assign[i].slots);
1444 const char *const string = (target_index == MESA_SHADER_VERTEX)
1445 ? "vertex shader input" : "fragment shader output";
1448 "insufficient contiguous attribute locations "
1449 "available for %s `%s'",
1450 string, to_assign[i].var->name);
1454 to_assign[i].var->location = generic_base + location;
1455 used_locations |= (use_mask << location);
1463 * Demote shader inputs and outputs that are not used in other stages
1466 demote_shader_inputs_and_outputs(gl_shader *sh, enum ir_variable_mode mode)
1468 foreach_list(node, sh->ir) {
1469 ir_variable *const var = ((ir_instruction *) node)->as_variable();
1471 if ((var == NULL) || (var->mode != int(mode)))
1474 /* A shader 'in' or 'out' variable is only really an input or output if
1475 * its value is used by other shader stages. This will cause the variable
1476 * to have a location assigned.
1478 if (var->location == -1) {
1479 var->mode = ir_var_auto;
1486 assign_varying_locations(struct gl_context *ctx,
1487 struct gl_shader_program *prog,
1488 gl_shader *producer, gl_shader *consumer)
1490 /* FINISHME: Set dynamically when geometry shader support is added. */
1491 unsigned output_index = VERT_RESULT_VAR0;
1492 unsigned input_index = FRAG_ATTRIB_VAR0;
1494 /* Operate in a total of three passes.
1496 * 1. Assign locations for any matching inputs and outputs.
1498 * 2. Mark output variables in the producer that do not have locations as
1499 * not being outputs. This lets the optimizer eliminate them.
1501 * 3. Mark input variables in the consumer that do not have locations as
1502 * not being inputs. This lets the optimizer eliminate them.
1505 invalidate_variable_locations(producer, ir_var_out, VERT_RESULT_VAR0);
1506 invalidate_variable_locations(consumer, ir_var_in, FRAG_ATTRIB_VAR0);
1508 foreach_list(node, producer->ir) {
1509 ir_variable *const output_var = ((ir_instruction *) node)->as_variable();
1511 if ((output_var == NULL) || (output_var->mode != ir_var_out)
1512 || (output_var->location != -1))
1515 ir_variable *const input_var =
1516 consumer->symbols->get_variable(output_var->name);
1518 if ((input_var == NULL) || (input_var->mode != ir_var_in))
1521 assert(input_var->location == -1);
1523 output_var->location = output_index;
1524 input_var->location = input_index;
1526 /* FINISHME: Support for "varying" records in GLSL 1.50. */
1527 assert(!output_var->type->is_record());
1529 if (output_var->type->is_array()) {
1530 const unsigned slots = output_var->type->length
1531 * output_var->type->fields.array->matrix_columns;
1533 output_index += slots;
1534 input_index += slots;
1536 const unsigned slots = output_var->type->matrix_columns;
1538 output_index += slots;
1539 input_index += slots;
1543 unsigned varying_vectors = 0;
1545 foreach_list(node, consumer->ir) {
1546 ir_variable *const var = ((ir_instruction *) node)->as_variable();
1548 if ((var == NULL) || (var->mode != ir_var_in))
1551 if (var->location == -1) {
1552 if (prog->Version <= 120) {
1553 /* On page 25 (page 31 of the PDF) of the GLSL 1.20 spec:
1555 * Only those varying variables used (i.e. read) in
1556 * the fragment shader executable must be written to
1557 * by the vertex shader executable; declaring
1558 * superfluous varying variables in a vertex shader is
1561 * We interpret this text as meaning that the VS must
1562 * write the variable for the FS to read it. See
1563 * "glsl1-varying read but not written" in piglit.
1566 linker_error(prog, "fragment shader varying %s not written "
1567 "by vertex shader\n.", var->name);
1570 /* An 'in' variable is only really a shader input if its
1571 * value is written by the previous stage.
1573 var->mode = ir_var_auto;
1575 /* The packing rules are used for vertex shader inputs are also used
1576 * for fragment shader inputs.
1578 varying_vectors += count_attribute_slots(var->type);
1582 if (ctx->API == API_OPENGLES2 || prog->Version == 100) {
1583 if (varying_vectors > ctx->Const.MaxVarying) {
1584 linker_error(prog, "shader uses too many varying vectors "
1586 varying_vectors, ctx->Const.MaxVarying);
1590 const unsigned float_components = varying_vectors * 4;
1591 if (float_components > ctx->Const.MaxVarying * 4) {
1592 linker_error(prog, "shader uses too many varying components "
1594 float_components, ctx->Const.MaxVarying * 4);
1604 link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
1606 void *mem_ctx = ralloc_context(NULL); // temporary linker context
1608 prog->LinkStatus = false;
1609 prog->Validated = false;
1610 prog->_Used = false;
1612 if (prog->InfoLog != NULL)
1613 ralloc_free(prog->InfoLog);
1615 prog->InfoLog = ralloc_strdup(NULL, "");
1617 /* Separate the shaders into groups based on their type.
1619 struct gl_shader **vert_shader_list;
1620 unsigned num_vert_shaders = 0;
1621 struct gl_shader **frag_shader_list;
1622 unsigned num_frag_shaders = 0;
1624 vert_shader_list = (struct gl_shader **)
1625 calloc(2 * prog->NumShaders, sizeof(struct gl_shader *));
1626 frag_shader_list = &vert_shader_list[prog->NumShaders];
1628 unsigned min_version = UINT_MAX;
1629 unsigned max_version = 0;
1630 for (unsigned i = 0; i < prog->NumShaders; i++) {
1631 min_version = MIN2(min_version, prog->Shaders[i]->Version);
1632 max_version = MAX2(max_version, prog->Shaders[i]->Version);
1634 switch (prog->Shaders[i]->Type) {
1635 case GL_VERTEX_SHADER:
1636 vert_shader_list[num_vert_shaders] = prog->Shaders[i];
1639 case GL_FRAGMENT_SHADER:
1640 frag_shader_list[num_frag_shaders] = prog->Shaders[i];
1643 case GL_GEOMETRY_SHADER:
1644 /* FINISHME: Support geometry shaders. */
1645 assert(prog->Shaders[i]->Type != GL_GEOMETRY_SHADER);
1650 /* Previous to GLSL version 1.30, different compilation units could mix and
1651 * match shading language versions. With GLSL 1.30 and later, the versions
1652 * of all shaders must match.
1654 assert(min_version >= 100);
1655 assert(max_version <= 130);
1656 if ((max_version >= 130 || min_version == 100)
1657 && min_version != max_version) {
1658 linker_error(prog, "all shaders must use same shading "
1659 "language version\n");
1663 prog->Version = max_version;
1665 for (unsigned int i = 0; i < MESA_SHADER_TYPES; i++) {
1666 if (prog->_LinkedShaders[i] != NULL)
1667 ctx->Driver.DeleteShader(ctx, prog->_LinkedShaders[i]);
1669 prog->_LinkedShaders[i] = NULL;
1672 /* Link all shaders for a particular stage and validate the result.
1674 if (num_vert_shaders > 0) {
1675 gl_shader *const sh =
1676 link_intrastage_shaders(mem_ctx, ctx, prog, vert_shader_list,
1682 if (!validate_vertex_shader_executable(prog, sh))
1685 _mesa_reference_shader(ctx, &prog->_LinkedShaders[MESA_SHADER_VERTEX],
1689 if (num_frag_shaders > 0) {
1690 gl_shader *const sh =
1691 link_intrastage_shaders(mem_ctx, ctx, prog, frag_shader_list,
1697 if (!validate_fragment_shader_executable(prog, sh))
1700 _mesa_reference_shader(ctx, &prog->_LinkedShaders[MESA_SHADER_FRAGMENT],
1704 /* Here begins the inter-stage linking phase. Some initial validation is
1705 * performed, then locations are assigned for uniforms, attributes, and
1708 if (cross_validate_uniforms(prog)) {
1711 for (prev = 0; prev < MESA_SHADER_TYPES; prev++) {
1712 if (prog->_LinkedShaders[prev] != NULL)
1716 /* Validate the inputs of each stage with the output of the preceding
1719 for (unsigned i = prev + 1; i < MESA_SHADER_TYPES; i++) {
1720 if (prog->_LinkedShaders[i] == NULL)
1723 if (!cross_validate_outputs_to_inputs(prog,
1724 prog->_LinkedShaders[prev],
1725 prog->_LinkedShaders[i]))
1731 prog->LinkStatus = true;
1734 /* Do common optimization before assigning storage for attributes,
1735 * uniforms, and varyings. Later optimization could possibly make
1736 * some of that unused.
1738 for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
1739 if (prog->_LinkedShaders[i] == NULL)
1742 detect_recursion_linked(prog, prog->_LinkedShaders[i]->ir);
1743 if (!prog->LinkStatus)
1746 if (ctx->ShaderCompilerOptions[i].LowerClipDistance)
1747 lower_clip_distance(prog->_LinkedShaders[i]->ir);
1749 while (do_common_optimization(prog->_LinkedShaders[i]->ir, true, 32))
1753 update_array_sizes(prog);
1755 assign_uniform_locations(prog);
1757 /* FINISHME: The value of the max_attribute_index parameter is
1758 * FINISHME: implementation dependent based on the value of
1759 * FINISHME: GL_MAX_VERTEX_ATTRIBS. GL_MAX_VERTEX_ATTRIBS must be
1760 * FINISHME: at least 16, so hardcode 16 for now.
1762 if (!assign_attribute_or_color_locations(prog, MESA_SHADER_VERTEX, 16)) {
1766 if (!assign_attribute_or_color_locations(prog, MESA_SHADER_FRAGMENT, ctx->Const.MaxDrawBuffers)) {
1771 for (prev = 0; prev < MESA_SHADER_TYPES; prev++) {
1772 if (prog->_LinkedShaders[prev] != NULL)
1776 for (unsigned i = prev + 1; i < MESA_SHADER_TYPES; i++) {
1777 if (prog->_LinkedShaders[i] == NULL)
1780 if (!assign_varying_locations(ctx, prog,
1781 prog->_LinkedShaders[prev],
1782 prog->_LinkedShaders[i])) {
1789 if (prog->_LinkedShaders[MESA_SHADER_VERTEX] != NULL) {
1790 demote_shader_inputs_and_outputs(prog->_LinkedShaders[MESA_SHADER_VERTEX],
1794 if (prog->_LinkedShaders[MESA_SHADER_GEOMETRY] != NULL) {
1795 gl_shader *const sh = prog->_LinkedShaders[MESA_SHADER_GEOMETRY];
1797 demote_shader_inputs_and_outputs(sh, ir_var_in);
1798 demote_shader_inputs_and_outputs(sh, ir_var_inout);
1799 demote_shader_inputs_and_outputs(sh, ir_var_out);
1802 if (prog->_LinkedShaders[MESA_SHADER_FRAGMENT] != NULL) {
1803 gl_shader *const sh = prog->_LinkedShaders[MESA_SHADER_FRAGMENT];
1805 demote_shader_inputs_and_outputs(sh, ir_var_in);
1808 /* OpenGL ES requires that a vertex shader and a fragment shader both be
1809 * present in a linked program. By checking for use of shading language
1810 * version 1.00, we also catch the GL_ARB_ES2_compatibility case.
1812 if (ctx->API == API_OPENGLES2 || prog->Version == 100) {
1813 if (prog->_LinkedShaders[MESA_SHADER_VERTEX] == NULL) {
1814 linker_error(prog, "program lacks a vertex shader\n");
1815 } else if (prog->_LinkedShaders[MESA_SHADER_FRAGMENT] == NULL) {
1816 linker_error(prog, "program lacks a fragment shader\n");
1820 /* FINISHME: Assign fragment shader output locations. */
1823 free(vert_shader_list);
1825 for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
1826 if (prog->_LinkedShaders[i] == NULL)
1829 /* Retain any live IR, but trash the rest. */
1830 reparent_ir(prog->_LinkedShaders[i]->ir, prog->_LinkedShaders[i]->ir);
1833 ralloc_free(mem_ctx);