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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>
71 #include "main/core.h"
72 #include "glsl_symbol_table.h"
75 #include "program/hash_table.h"
77 #include "ir_optimization.h"
80 #include "main/shaderobj.h"
84 * Visitor that determines whether or not a variable is ever written.
86 class find_assignment_visitor : public ir_hierarchical_visitor {
88 find_assignment_visitor(const char *name)
89 : name(name), found(false)
94 virtual ir_visitor_status visit_enter(ir_assignment *ir)
96 ir_variable *const var = ir->lhs->variable_referenced();
98 if (strcmp(name, var->name) == 0) {
103 return visit_continue_with_parent;
106 virtual ir_visitor_status visit_enter(ir_call *ir)
108 exec_list_iterator sig_iter = ir->get_callee()->parameters.iterator();
109 foreach_iter(exec_list_iterator, iter, *ir) {
110 ir_rvalue *param_rval = (ir_rvalue *)iter.get();
111 ir_variable *sig_param = (ir_variable *)sig_iter.get();
113 if (sig_param->mode == ir_var_out ||
114 sig_param->mode == ir_var_inout) {
115 ir_variable *var = param_rval->variable_referenced();
116 if (var && strcmp(name, var->name) == 0) {
124 return visit_continue_with_parent;
127 bool variable_found()
133 const char *name; /**< Find writes to a variable with this name. */
134 bool found; /**< Was a write to the variable found? */
139 * Visitor that determines whether or not a variable is ever read.
141 class find_deref_visitor : public ir_hierarchical_visitor {
143 find_deref_visitor(const char *name)
144 : name(name), found(false)
149 virtual ir_visitor_status visit(ir_dereference_variable *ir)
151 if (strcmp(this->name, ir->var->name) == 0) {
156 return visit_continue;
159 bool variable_found() const
165 const char *name; /**< Find writes to a variable with this name. */
166 bool found; /**< Was a write to the variable found? */
171 linker_error_printf(gl_shader_program *prog, const char *fmt, ...)
175 prog->InfoLog = talloc_strdup_append(prog->InfoLog, "error: ");
177 prog->InfoLog = talloc_vasprintf_append(prog->InfoLog, fmt, ap);
183 invalidate_variable_locations(gl_shader *sh, enum ir_variable_mode mode,
186 foreach_list(node, sh->ir) {
187 ir_variable *const var = ((ir_instruction *) node)->as_variable();
189 if ((var == NULL) || (var->mode != (unsigned) mode))
192 /* Only assign locations for generic attributes / varyings / etc.
194 if ((var->location >= generic_base) && !var->explicit_location)
201 * Determine the number of attribute slots required for a particular type
203 * This code is here because it implements the language rules of a specific
204 * GLSL version. Since it's a property of the language and not a property of
205 * types in general, it doesn't really belong in glsl_type.
208 count_attribute_slots(const glsl_type *t)
210 /* From page 31 (page 37 of the PDF) of the GLSL 1.50 spec:
212 * "A scalar input counts the same amount against this limit as a vec4,
213 * so applications may want to consider packing groups of four
214 * unrelated float inputs together into a vector to better utilize the
215 * capabilities of the underlying hardware. A matrix input will use up
216 * multiple locations. The number of locations used will equal the
217 * number of columns in the matrix."
219 * The spec does not explicitly say how arrays are counted. However, it
220 * should be safe to assume the total number of slots consumed by an array
221 * is the number of entries in the array multiplied by the number of slots
222 * consumed by a single element of the array.
226 return t->array_size() * count_attribute_slots(t->element_type());
229 return t->matrix_columns;
236 * Verify that a vertex shader executable meets all semantic requirements
238 * \param shader Vertex shader executable to be verified
241 validate_vertex_shader_executable(struct gl_shader_program *prog,
242 struct gl_shader *shader)
247 find_assignment_visitor find("gl_Position");
248 find.run(shader->ir);
249 if (!find.variable_found()) {
250 linker_error_printf(prog,
251 "vertex shader does not write to `gl_Position'\n");
260 * Verify that a fragment shader executable meets all semantic requirements
262 * \param shader Fragment shader executable to be verified
265 validate_fragment_shader_executable(struct gl_shader_program *prog,
266 struct gl_shader *shader)
271 find_assignment_visitor frag_color("gl_FragColor");
272 find_assignment_visitor frag_data("gl_FragData");
274 frag_color.run(shader->ir);
275 frag_data.run(shader->ir);
277 if (frag_color.variable_found() && frag_data.variable_found()) {
278 linker_error_printf(prog, "fragment shader writes to both "
279 "`gl_FragColor' and `gl_FragData'\n");
288 * Generate a string describing the mode of a variable
291 mode_string(const ir_variable *var)
295 return (var->read_only) ? "global constant" : "global variable";
297 case ir_var_uniform: return "uniform";
298 case ir_var_in: return "shader input";
299 case ir_var_out: return "shader output";
300 case ir_var_inout: return "shader inout";
302 case ir_var_temporary:
304 assert(!"Should not get here.");
305 return "invalid variable";
311 * Perform validation of global variables used across multiple shaders
314 cross_validate_globals(struct gl_shader_program *prog,
315 struct gl_shader **shader_list,
316 unsigned num_shaders,
319 /* Examine all of the uniforms in all of the shaders and cross validate
322 glsl_symbol_table variables;
323 for (unsigned i = 0; i < num_shaders; i++) {
324 if (shader_list[i] == NULL)
327 foreach_list(node, shader_list[i]->ir) {
328 ir_variable *const var = ((ir_instruction *) node)->as_variable();
333 if (uniforms_only && (var->mode != ir_var_uniform))
336 /* Don't cross validate temporaries that are at global scope. These
337 * will eventually get pulled into the shaders 'main'.
339 if (var->mode == ir_var_temporary)
342 /* If a global with this name has already been seen, verify that the
343 * new instance has the same type. In addition, if the globals have
344 * initializers, the values of the initializers must be the same.
346 ir_variable *const existing = variables.get_variable(var->name);
347 if (existing != NULL) {
348 if (var->type != existing->type) {
349 /* Consider the types to be "the same" if both types are arrays
350 * of the same type and one of the arrays is implicitly sized.
351 * In addition, set the type of the linked variable to the
352 * explicitly sized array.
354 if (var->type->is_array()
355 && existing->type->is_array()
356 && (var->type->fields.array == existing->type->fields.array)
357 && ((var->type->length == 0)
358 || (existing->type->length == 0))) {
359 if (existing->type->length == 0) {
360 existing->type = var->type;
361 existing->max_array_access =
362 MAX2(existing->max_array_access,
363 var->max_array_access);
366 linker_error_printf(prog, "%s `%s' declared as type "
367 "`%s' and type `%s'\n",
369 var->name, var->type->name,
370 existing->type->name);
375 if (var->explicit_location) {
376 if (existing->explicit_location
377 && (var->location != existing->location)) {
378 linker_error_printf(prog, "explicit locations for %s "
379 "`%s' have differing values\n",
380 mode_string(var), var->name);
384 existing->location = var->location;
385 existing->explicit_location = true;
388 /* FINISHME: Handle non-constant initializers.
390 if (var->constant_value != NULL) {
391 if (existing->constant_value != NULL) {
392 if (!var->constant_value->has_value(existing->constant_value)) {
393 linker_error_printf(prog, "initializers for %s "
394 "`%s' have differing values\n",
395 mode_string(var), var->name);
399 /* If the first-seen instance of a particular uniform did not
400 * have an initializer but a later instance does, copy the
401 * initializer to the version stored in the symbol table.
403 /* FINISHME: This is wrong. The constant_value field should
404 * FINISHME: not be modified! Imagine a case where a shader
405 * FINISHME: without an initializer is linked in two different
406 * FINISHME: programs with shaders that have differing
407 * FINISHME: initializers. Linking with the first will
408 * FINISHME: modify the shader, and linking with the second
409 * FINISHME: will fail.
411 existing->constant_value =
412 var->constant_value->clone(talloc_parent(existing), NULL);
415 if (existing->invariant != var->invariant) {
416 linker_error_printf(prog, "declarations for %s `%s' have "
417 "mismatching invariant qualifiers\n",
418 mode_string(var), var->name);
421 if (existing->centroid != var->centroid) {
422 linker_error_printf(prog, "declarations for %s `%s' have "
423 "mismatching centroid qualifiers\n",
424 mode_string(var), var->name);
428 variables.add_variable(var);
437 * Perform validation of uniforms used across multiple shader stages
440 cross_validate_uniforms(struct gl_shader_program *prog)
442 return cross_validate_globals(prog, prog->_LinkedShaders,
443 MESA_SHADER_TYPES, true);
448 * Validate that outputs from one stage match inputs of another
451 cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
452 gl_shader *producer, gl_shader *consumer)
454 glsl_symbol_table parameters;
455 /* FINISHME: Figure these out dynamically. */
456 const char *const producer_stage = "vertex";
457 const char *const consumer_stage = "fragment";
459 /* Find all shader outputs in the "producer" stage.
461 foreach_list(node, producer->ir) {
462 ir_variable *const var = ((ir_instruction *) node)->as_variable();
464 /* FINISHME: For geometry shaders, this should also look for inout
465 * FINISHME: variables.
467 if ((var == NULL) || (var->mode != ir_var_out))
470 parameters.add_variable(var);
474 /* Find all shader inputs in the "consumer" stage. Any variables that have
475 * matching outputs already in the symbol table must have the same type and
478 foreach_list(node, consumer->ir) {
479 ir_variable *const input = ((ir_instruction *) node)->as_variable();
481 /* FINISHME: For geometry shaders, this should also look for inout
482 * FINISHME: variables.
484 if ((input == NULL) || (input->mode != ir_var_in))
487 ir_variable *const output = parameters.get_variable(input->name);
488 if (output != NULL) {
489 /* Check that the types match between stages.
491 if (input->type != output->type) {
492 /* There is a bit of a special case for gl_TexCoord. This
493 * built-in is unsized by default. Appliations that variable
494 * access it must redeclare it with a size. There is some
495 * language in the GLSL spec that implies the fragment shader
496 * and vertex shader do not have to agree on this size. Other
497 * driver behave this way, and one or two applications seem to
500 * Neither declaration needs to be modified here because the array
501 * sizes are fixed later when update_array_sizes is called.
503 * From page 48 (page 54 of the PDF) of the GLSL 1.10 spec:
505 * "Unlike user-defined varying variables, the built-in
506 * varying variables don't have a strict one-to-one
507 * correspondence between the vertex language and the
508 * fragment language."
510 if (!output->type->is_array()
511 || (strncmp("gl_", output->name, 3) != 0)) {
512 linker_error_printf(prog,
513 "%s shader output `%s' declared as "
514 "type `%s', but %s shader input declared "
516 producer_stage, output->name,
518 consumer_stage, input->type->name);
523 /* Check that all of the qualifiers match between stages.
525 if (input->centroid != output->centroid) {
526 linker_error_printf(prog,
527 "%s shader output `%s' %s centroid qualifier, "
528 "but %s shader input %s centroid qualifier\n",
531 (output->centroid) ? "has" : "lacks",
533 (input->centroid) ? "has" : "lacks");
537 if (input->invariant != output->invariant) {
538 linker_error_printf(prog,
539 "%s shader output `%s' %s invariant qualifier, "
540 "but %s shader input %s invariant qualifier\n",
543 (output->invariant) ? "has" : "lacks",
545 (input->invariant) ? "has" : "lacks");
549 if (input->interpolation != output->interpolation) {
550 linker_error_printf(prog,
551 "%s shader output `%s' specifies %s "
552 "interpolation qualifier, "
553 "but %s shader input specifies %s "
554 "interpolation qualifier\n",
557 output->interpolation_string(),
559 input->interpolation_string());
570 * Populates a shaders symbol table with all global declarations
573 populate_symbol_table(gl_shader *sh)
575 sh->symbols = new(sh) glsl_symbol_table;
577 foreach_list(node, sh->ir) {
578 ir_instruction *const inst = (ir_instruction *) node;
582 if ((func = inst->as_function()) != NULL) {
583 sh->symbols->add_function(func);
584 } else if ((var = inst->as_variable()) != NULL) {
585 sh->symbols->add_variable(var);
592 * Remap variables referenced in an instruction tree
594 * This is used when instruction trees are cloned from one shader and placed in
595 * another. These trees will contain references to \c ir_variable nodes that
596 * do not exist in the target shader. This function finds these \c ir_variable
597 * references and replaces the references with matching variables in the target
600 * If there is no matching variable in the target shader, a clone of the
601 * \c ir_variable is made and added to the target shader. The new variable is
602 * added to \b both the instruction stream and the symbol table.
604 * \param inst IR tree that is to be processed.
605 * \param symbols Symbol table containing global scope symbols in the
607 * \param instructions Instruction stream where new variable declarations
611 remap_variables(ir_instruction *inst, struct gl_shader *target,
614 class remap_visitor : public ir_hierarchical_visitor {
616 remap_visitor(struct gl_shader *target,
619 this->target = target;
620 this->symbols = target->symbols;
621 this->instructions = target->ir;
625 virtual ir_visitor_status visit(ir_dereference_variable *ir)
627 if (ir->var->mode == ir_var_temporary) {
628 ir_variable *var = (ir_variable *) hash_table_find(temps, ir->var);
632 return visit_continue;
635 ir_variable *const existing =
636 this->symbols->get_variable(ir->var->name);
637 if (existing != NULL)
640 ir_variable *copy = ir->var->clone(this->target, NULL);
642 this->symbols->add_variable(copy);
643 this->instructions->push_head(copy);
647 return visit_continue;
651 struct gl_shader *target;
652 glsl_symbol_table *symbols;
653 exec_list *instructions;
657 remap_visitor v(target, temps);
664 * Move non-declarations from one instruction stream to another
666 * The intended usage pattern of this function is to pass the pointer to the
667 * head sentinel of a list (i.e., a pointer to the list cast to an \c exec_node
668 * pointer) for \c last and \c false for \c make_copies on the first
669 * call. Successive calls pass the return value of the previous call for
670 * \c last and \c true for \c make_copies.
672 * \param instructions Source instruction stream
673 * \param last Instruction after which new instructions should be
674 * inserted in the target instruction stream
675 * \param make_copies Flag selecting whether instructions in \c instructions
676 * should be copied (via \c ir_instruction::clone) into the
677 * target list or moved.
680 * The new "last" instruction in the target instruction stream. This pointer
681 * is suitable for use as the \c last parameter of a later call to this
685 move_non_declarations(exec_list *instructions, exec_node *last,
686 bool make_copies, gl_shader *target)
688 hash_table *temps = NULL;
691 temps = hash_table_ctor(0, hash_table_pointer_hash,
692 hash_table_pointer_compare);
694 foreach_list_safe(node, instructions) {
695 ir_instruction *inst = (ir_instruction *) node;
697 if (inst->as_function())
700 ir_variable *var = inst->as_variable();
701 if ((var != NULL) && (var->mode != ir_var_temporary))
704 assert(inst->as_assignment()
705 || ((var != NULL) && (var->mode == ir_var_temporary)));
708 inst = inst->clone(target, NULL);
711 hash_table_insert(temps, inst, var);
713 remap_variables(inst, target, temps);
718 last->insert_after(inst);
723 hash_table_dtor(temps);
729 * Get the function signature for main from a shader
731 static ir_function_signature *
732 get_main_function_signature(gl_shader *sh)
734 ir_function *const f = sh->symbols->get_function("main");
736 exec_list void_parameters;
738 /* Look for the 'void main()' signature and ensure that it's defined.
739 * This keeps the linker from accidentally pick a shader that just
740 * contains a prototype for main.
742 * We don't have to check for multiple definitions of main (in multiple
743 * shaders) because that would have already been caught above.
745 ir_function_signature *sig = f->matching_signature(&void_parameters);
746 if ((sig != NULL) && sig->is_defined) {
756 * Combine a group of shaders for a single stage to generate a linked shader
759 * If this function is supplied a single shader, it is cloned, and the new
760 * shader is returned.
762 static struct gl_shader *
763 link_intrastage_shaders(void *mem_ctx,
764 struct gl_context *ctx,
765 struct gl_shader_program *prog,
766 struct gl_shader **shader_list,
767 unsigned num_shaders)
769 /* Check that global variables defined in multiple shaders are consistent.
771 if (!cross_validate_globals(prog, shader_list, num_shaders, false))
774 /* Check that there is only a single definition of each function signature
775 * across all shaders.
777 for (unsigned i = 0; i < (num_shaders - 1); i++) {
778 foreach_list(node, shader_list[i]->ir) {
779 ir_function *const f = ((ir_instruction *) node)->as_function();
784 for (unsigned j = i + 1; j < num_shaders; j++) {
785 ir_function *const other =
786 shader_list[j]->symbols->get_function(f->name);
788 /* If the other shader has no function (and therefore no function
789 * signatures) with the same name, skip to the next shader.
794 foreach_iter (exec_list_iterator, iter, *f) {
795 ir_function_signature *sig =
796 (ir_function_signature *) iter.get();
798 if (!sig->is_defined || sig->is_builtin)
801 ir_function_signature *other_sig =
802 other->exact_matching_signature(& sig->parameters);
804 if ((other_sig != NULL) && other_sig->is_defined
805 && !other_sig->is_builtin) {
806 linker_error_printf(prog,
807 "function `%s' is multiply defined",
816 /* Find the shader that defines main, and make a clone of it.
818 * Starting with the clone, search for undefined references. If one is
819 * found, find the shader that defines it. Clone the reference and add
820 * it to the shader. Repeat until there are no undefined references or
821 * until a reference cannot be resolved.
823 gl_shader *main = NULL;
824 for (unsigned i = 0; i < num_shaders; i++) {
825 if (get_main_function_signature(shader_list[i]) != NULL) {
826 main = shader_list[i];
832 linker_error_printf(prog, "%s shader lacks `main'\n",
833 (shader_list[0]->Type == GL_VERTEX_SHADER)
834 ? "vertex" : "fragment");
838 gl_shader *linked = ctx->Driver.NewShader(NULL, 0, main->Type);
839 linked->ir = new(linked) exec_list;
840 clone_ir_list(mem_ctx, linked->ir, main->ir);
842 populate_symbol_table(linked);
844 /* The a pointer to the main function in the final linked shader (i.e., the
845 * copy of the original shader that contained the main function).
847 ir_function_signature *const main_sig = get_main_function_signature(linked);
849 /* Move any instructions other than variable declarations or function
850 * declarations into main.
852 exec_node *insertion_point =
853 move_non_declarations(linked->ir, (exec_node *) &main_sig->body, false,
856 for (unsigned i = 0; i < num_shaders; i++) {
857 if (shader_list[i] == main)
860 insertion_point = move_non_declarations(shader_list[i]->ir,
861 insertion_point, true, linked);
864 /* Resolve initializers for global variables in the linked shader.
866 unsigned num_linking_shaders = num_shaders;
867 for (unsigned i = 0; i < num_shaders; i++)
868 num_linking_shaders += shader_list[i]->num_builtins_to_link;
870 gl_shader **linking_shaders =
871 (gl_shader **) calloc(num_linking_shaders, sizeof(gl_shader *));
873 memcpy(linking_shaders, shader_list,
874 sizeof(linking_shaders[0]) * num_shaders);
876 unsigned idx = num_shaders;
877 for (unsigned i = 0; i < num_shaders; i++) {
878 memcpy(&linking_shaders[idx], shader_list[i]->builtins_to_link,
879 sizeof(linking_shaders[0]) * shader_list[i]->num_builtins_to_link);
880 idx += shader_list[i]->num_builtins_to_link;
883 assert(idx == num_linking_shaders);
885 if (!link_function_calls(prog, linked, linking_shaders,
886 num_linking_shaders)) {
887 ctx->Driver.DeleteShader(ctx, linked);
891 free(linking_shaders);
893 /* Make a pass over all variable declarations to ensure that arrays with
894 * unspecified sizes have a size specified. The size is inferred from the
895 * max_array_access field.
897 if (linked != NULL) {
898 class array_sizing_visitor : public ir_hierarchical_visitor {
900 virtual ir_visitor_status visit(ir_variable *var)
902 if (var->type->is_array() && (var->type->length == 0)) {
903 const glsl_type *type =
904 glsl_type::get_array_instance(var->type->fields.array,
905 var->max_array_access);
907 assert(type != NULL);
911 return visit_continue;
922 struct uniform_node {
924 struct gl_uniform *u;
929 * Update the sizes of linked shader uniform arrays to the maximum
932 * From page 81 (page 95 of the PDF) of the OpenGL 2.1 spec:
934 * If one or more elements of an array are active,
935 * GetActiveUniform will return the name of the array in name,
936 * subject to the restrictions listed above. The type of the array
937 * is returned in type. The size parameter contains the highest
938 * array element index used, plus one. The compiler or linker
939 * determines the highest index used. There will be only one
940 * active uniform reported by the GL per uniform array.
944 update_array_sizes(struct gl_shader_program *prog)
946 for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
947 if (prog->_LinkedShaders[i] == NULL)
950 foreach_list(node, prog->_LinkedShaders[i]->ir) {
951 ir_variable *const var = ((ir_instruction *) node)->as_variable();
953 if ((var == NULL) || (var->mode != ir_var_uniform &&
954 var->mode != ir_var_in &&
955 var->mode != ir_var_out) ||
956 !var->type->is_array())
959 unsigned int size = var->max_array_access;
960 for (unsigned j = 0; j < MESA_SHADER_TYPES; j++) {
961 if (prog->_LinkedShaders[j] == NULL)
964 foreach_list(node2, prog->_LinkedShaders[j]->ir) {
965 ir_variable *other_var = ((ir_instruction *) node2)->as_variable();
969 if (strcmp(var->name, other_var->name) == 0 &&
970 other_var->max_array_access > size) {
971 size = other_var->max_array_access;
976 if (size + 1 != var->type->fields.array->length) {
977 var->type = glsl_type::get_array_instance(var->type->fields.array,
979 /* FINISHME: We should update the types of array
980 * dereferences of this variable now.
988 add_uniform(void *mem_ctx, exec_list *uniforms, struct hash_table *ht,
989 const char *name, const glsl_type *type, GLenum shader_type,
990 unsigned *next_shader_pos, unsigned *total_uniforms)
992 if (type->is_record()) {
993 for (unsigned int i = 0; i < type->length; i++) {
994 const glsl_type *field_type = type->fields.structure[i].type;
995 char *field_name = talloc_asprintf(mem_ctx, "%s.%s", name,
996 type->fields.structure[i].name);
998 add_uniform(mem_ctx, uniforms, ht, field_name, field_type,
999 shader_type, next_shader_pos, total_uniforms);
1002 uniform_node *n = (uniform_node *) hash_table_find(ht, name);
1003 unsigned int vec4_slots;
1004 const glsl_type *array_elem_type = NULL;
1006 if (type->is_array()) {
1007 array_elem_type = type->fields.array;
1008 /* Array of structures. */
1009 if (array_elem_type->is_record()) {
1010 for (unsigned int i = 0; i < type->length; i++) {
1011 char *elem_name = talloc_asprintf(mem_ctx, "%s[%d]", name, i);
1012 add_uniform(mem_ctx, uniforms, ht, elem_name, array_elem_type,
1013 shader_type, next_shader_pos, total_uniforms);
1019 /* Fix the storage size of samplers at 1 vec4 each. Be sure to pad out
1020 * vectors to vec4 slots.
1022 if (type->is_array()) {
1023 if (array_elem_type->is_sampler())
1024 vec4_slots = type->length;
1026 vec4_slots = type->length * array_elem_type->matrix_columns;
1027 } else if (type->is_sampler()) {
1030 vec4_slots = type->matrix_columns;
1034 n = (uniform_node *) calloc(1, sizeof(struct uniform_node));
1035 n->u = (gl_uniform *) calloc(1, sizeof(struct gl_uniform));
1036 n->slots = vec4_slots;
1038 n->u->Name = strdup(name);
1043 (*total_uniforms)++;
1045 hash_table_insert(ht, n, name);
1046 uniforms->push_tail(& n->link);
1049 switch (shader_type) {
1050 case GL_VERTEX_SHADER:
1051 n->u->VertPos = *next_shader_pos;
1053 case GL_FRAGMENT_SHADER:
1054 n->u->FragPos = *next_shader_pos;
1056 case GL_GEOMETRY_SHADER:
1057 n->u->GeomPos = *next_shader_pos;
1061 (*next_shader_pos) += vec4_slots;
1066 assign_uniform_locations(struct gl_shader_program *prog)
1070 unsigned total_uniforms = 0;
1071 hash_table *ht = hash_table_ctor(32, hash_table_string_hash,
1072 hash_table_string_compare);
1073 void *mem_ctx = talloc_new(NULL);
1075 for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
1076 if (prog->_LinkedShaders[i] == NULL)
1079 unsigned next_position = 0;
1081 foreach_list(node, prog->_LinkedShaders[i]->ir) {
1082 ir_variable *const var = ((ir_instruction *) node)->as_variable();
1084 if ((var == NULL) || (var->mode != ir_var_uniform))
1087 if (strncmp(var->name, "gl_", 3) == 0) {
1088 /* At the moment, we don't allocate uniform locations for
1089 * builtin uniforms. It's permitted by spec, and we'll
1090 * likely switch to doing that at some point, but not yet.
1095 var->location = next_position;
1096 add_uniform(mem_ctx, &uniforms, ht, var->name, var->type,
1097 prog->_LinkedShaders[i]->Type,
1098 &next_position, &total_uniforms);
1102 talloc_free(mem_ctx);
1104 gl_uniform_list *ul = (gl_uniform_list *)
1105 calloc(1, sizeof(gl_uniform_list));
1107 ul->Size = total_uniforms;
1108 ul->NumUniforms = total_uniforms;
1109 ul->Uniforms = (gl_uniform *) calloc(total_uniforms, sizeof(gl_uniform));
1113 for (uniform_node *node = (uniform_node *) uniforms.head
1114 ; node->link.next != NULL
1116 next = (uniform_node *) node->link.next;
1118 node->link.remove();
1119 memcpy(&ul->Uniforms[idx], node->u, sizeof(gl_uniform));
1126 hash_table_dtor(ht);
1128 prog->Uniforms = ul;
1133 * Find a contiguous set of available bits in a bitmask
1135 * \param used_mask Bits representing used (1) and unused (0) locations
1136 * \param needed_count Number of contiguous bits needed.
1139 * Base location of the available bits on success or -1 on failure.
1142 find_available_slots(unsigned used_mask, unsigned needed_count)
1144 unsigned needed_mask = (1 << needed_count) - 1;
1145 const int max_bit_to_test = (8 * sizeof(used_mask)) - needed_count;
1147 /* The comparison to 32 is redundant, but without it GCC emits "warning:
1148 * cannot optimize possibly infinite loops" for the loop below.
1150 if ((needed_count == 0) || (max_bit_to_test < 0) || (max_bit_to_test > 32))
1153 for (int i = 0; i <= max_bit_to_test; i++) {
1154 if ((needed_mask & ~used_mask) == needed_mask)
1165 assign_attribute_locations(gl_shader_program *prog, unsigned max_attribute_index)
1167 /* Mark invalid attribute locations as being used.
1169 unsigned used_locations = (max_attribute_index >= 32)
1170 ? ~0 : ~((1 << max_attribute_index) - 1);
1172 gl_shader *const sh = prog->_LinkedShaders[0];
1173 assert(sh->Type == GL_VERTEX_SHADER);
1175 /* Operate in a total of four passes.
1177 * 1. Invalidate the location assignments for all vertex shader inputs.
1179 * 2. Assign locations for inputs that have user-defined (via
1180 * glBindVertexAttribLocation) locatoins.
1182 * 3. Sort the attributes without assigned locations by number of slots
1183 * required in decreasing order. Fragmentation caused by attribute
1184 * locations assigned by the application may prevent large attributes
1185 * from having enough contiguous space.
1187 * 4. Assign locations to any inputs without assigned locations.
1190 invalidate_variable_locations(sh, ir_var_in, VERT_ATTRIB_GENERIC0);
1192 if (prog->Attributes != NULL) {
1193 for (unsigned i = 0; i < prog->Attributes->NumParameters; i++) {
1194 ir_variable *const var =
1195 sh->symbols->get_variable(prog->Attributes->Parameters[i].Name);
1197 /* Note: attributes that occupy multiple slots, such as arrays or
1198 * matrices, may appear in the attrib array multiple times.
1200 if ((var == NULL) || (var->location != -1))
1203 /* From page 61 of the OpenGL 4.0 spec:
1205 * "LinkProgram will fail if the attribute bindings assigned by
1206 * BindAttribLocation do not leave not enough space to assign a
1207 * location for an active matrix attribute or an active attribute
1208 * array, both of which require multiple contiguous generic
1211 * Previous versions of the spec contain similar language but omit the
1212 * bit about attribute arrays.
1214 * Page 61 of the OpenGL 4.0 spec also says:
1216 * "It is possible for an application to bind more than one
1217 * attribute name to the same location. This is referred to as
1218 * aliasing. This will only work if only one of the aliased
1219 * attributes is active in the executable program, or if no path
1220 * through the shader consumes more than one attribute of a set
1221 * of attributes aliased to the same location. A link error can
1222 * occur if the linker determines that every path through the
1223 * shader consumes multiple aliased attributes, but
1224 * implementations are not required to generate an error in this
1227 * These two paragraphs are either somewhat contradictory, or I don't
1228 * fully understand one or both of them.
1230 /* FINISHME: The code as currently written does not support attribute
1231 * FINISHME: location aliasing (see comment above).
1233 const int attr = prog->Attributes->Parameters[i].StateIndexes[0];
1234 const unsigned slots = count_attribute_slots(var->type);
1236 /* Mask representing the contiguous slots that will be used by this
1239 const unsigned use_mask = (1 << slots) - 1;
1241 /* Generate a link error if the set of bits requested for this
1242 * attribute overlaps any previously allocated bits.
1244 if ((~(use_mask << attr) & used_locations) != used_locations) {
1245 linker_error_printf(prog,
1246 "insufficient contiguous attribute locations "
1247 "available for vertex shader input `%s'",
1252 var->location = VERT_ATTRIB_GENERIC0 + attr;
1253 used_locations |= (use_mask << attr);
1257 /* Temporary storage for the set of attributes that need locations assigned.
1263 /* Used below in the call to qsort. */
1264 static int compare(const void *a, const void *b)
1266 const temp_attr *const l = (const temp_attr *) a;
1267 const temp_attr *const r = (const temp_attr *) b;
1269 /* Reversed because we want a descending order sort below. */
1270 return r->slots - l->slots;
1274 unsigned num_attr = 0;
1276 foreach_list(node, sh->ir) {
1277 ir_variable *const var = ((ir_instruction *) node)->as_variable();
1279 if ((var == NULL) || (var->mode != ir_var_in))
1282 if (var->explicit_location) {
1283 const unsigned slots = count_attribute_slots(var->type);
1284 const unsigned use_mask = (1 << slots) - 1;
1285 const int attr = var->location - VERT_ATTRIB_GENERIC0;
1287 if ((var->location >= (int)(max_attribute_index + VERT_ATTRIB_GENERIC0))
1288 || (var->location < 0)) {
1289 linker_error_printf(prog,
1290 "invalid explicit location %d specified for "
1292 (var->location < 0) ? var->location : attr,
1295 } else if (var->location >= VERT_ATTRIB_GENERIC0) {
1296 used_locations |= (use_mask << attr);
1300 /* The location was explicitly assigned, nothing to do here.
1302 if (var->location != -1)
1305 to_assign[num_attr].slots = count_attribute_slots(var->type);
1306 to_assign[num_attr].var = var;
1310 /* If all of the attributes were assigned locations by the application (or
1311 * are built-in attributes with fixed locations), return early. This should
1312 * be the common case.
1317 qsort(to_assign, num_attr, sizeof(to_assign[0]), temp_attr::compare);
1319 /* VERT_ATTRIB_GENERIC0 is a psdueo-alias for VERT_ATTRIB_POS. It can only
1320 * be explicitly assigned by via glBindAttribLocation. Mark it as reserved
1321 * to prevent it from being automatically allocated below.
1323 find_deref_visitor find("gl_Vertex");
1325 if (find.variable_found())
1326 used_locations |= (1 << 0);
1328 for (unsigned i = 0; i < num_attr; i++) {
1329 /* Mask representing the contiguous slots that will be used by this
1332 const unsigned use_mask = (1 << to_assign[i].slots) - 1;
1334 int location = find_available_slots(used_locations, to_assign[i].slots);
1337 linker_error_printf(prog,
1338 "insufficient contiguous attribute locations "
1339 "available for vertex shader input `%s'",
1340 to_assign[i].var->name);
1344 to_assign[i].var->location = VERT_ATTRIB_GENERIC0 + location;
1345 used_locations |= (use_mask << location);
1353 * Demote shader inputs and outputs that are not used in other stages
1356 demote_shader_inputs_and_outputs(gl_shader *sh, enum ir_variable_mode mode)
1358 foreach_list(node, sh->ir) {
1359 ir_variable *const var = ((ir_instruction *) node)->as_variable();
1361 if ((var == NULL) || (var->mode != int(mode)))
1364 /* A shader 'in' or 'out' variable is only really an input or output if
1365 * its value is used by other shader stages. This will cause the variable
1366 * to have a location assigned.
1368 if (var->location == -1) {
1369 var->mode = ir_var_auto;
1376 assign_varying_locations(struct gl_shader_program *prog,
1377 gl_shader *producer, gl_shader *consumer)
1379 /* FINISHME: Set dynamically when geometry shader support is added. */
1380 unsigned output_index = VERT_RESULT_VAR0;
1381 unsigned input_index = FRAG_ATTRIB_VAR0;
1383 /* Operate in a total of three passes.
1385 * 1. Assign locations for any matching inputs and outputs.
1387 * 2. Mark output variables in the producer that do not have locations as
1388 * not being outputs. This lets the optimizer eliminate them.
1390 * 3. Mark input variables in the consumer that do not have locations as
1391 * not being inputs. This lets the optimizer eliminate them.
1394 invalidate_variable_locations(producer, ir_var_out, VERT_RESULT_VAR0);
1395 invalidate_variable_locations(consumer, ir_var_in, FRAG_ATTRIB_VAR0);
1397 foreach_list(node, producer->ir) {
1398 ir_variable *const output_var = ((ir_instruction *) node)->as_variable();
1400 if ((output_var == NULL) || (output_var->mode != ir_var_out)
1401 || (output_var->location != -1))
1404 ir_variable *const input_var =
1405 consumer->symbols->get_variable(output_var->name);
1407 if ((input_var == NULL) || (input_var->mode != ir_var_in))
1410 assert(input_var->location == -1);
1412 output_var->location = output_index;
1413 input_var->location = input_index;
1415 /* FINISHME: Support for "varying" records in GLSL 1.50. */
1416 assert(!output_var->type->is_record());
1418 if (output_var->type->is_array()) {
1419 const unsigned slots = output_var->type->length
1420 * output_var->type->fields.array->matrix_columns;
1422 output_index += slots;
1423 input_index += slots;
1425 const unsigned slots = output_var->type->matrix_columns;
1427 output_index += slots;
1428 input_index += slots;
1432 foreach_list(node, consumer->ir) {
1433 ir_variable *const var = ((ir_instruction *) node)->as_variable();
1435 if ((var == NULL) || (var->mode != ir_var_in))
1438 if (var->location == -1) {
1439 if (prog->Version <= 120) {
1440 /* On page 25 (page 31 of the PDF) of the GLSL 1.20 spec:
1442 * Only those varying variables used (i.e. read) in
1443 * the fragment shader executable must be written to
1444 * by the vertex shader executable; declaring
1445 * superfluous varying variables in a vertex shader is
1448 * We interpret this text as meaning that the VS must
1449 * write the variable for the FS to read it. See
1450 * "glsl1-varying read but not written" in piglit.
1453 linker_error_printf(prog, "fragment shader varying %s not written "
1454 "by vertex shader\n.", var->name);
1455 prog->LinkStatus = false;
1458 /* An 'in' variable is only really a shader input if its
1459 * value is written by the previous stage.
1461 var->mode = ir_var_auto;
1468 link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
1470 void *mem_ctx = talloc_init("temporary linker context");
1472 prog->LinkStatus = false;
1473 prog->Validated = false;
1474 prog->_Used = false;
1476 if (prog->InfoLog != NULL)
1477 talloc_free(prog->InfoLog);
1479 prog->InfoLog = talloc_strdup(NULL, "");
1481 /* Separate the shaders into groups based on their type.
1483 struct gl_shader **vert_shader_list;
1484 unsigned num_vert_shaders = 0;
1485 struct gl_shader **frag_shader_list;
1486 unsigned num_frag_shaders = 0;
1488 vert_shader_list = (struct gl_shader **)
1489 calloc(2 * prog->NumShaders, sizeof(struct gl_shader *));
1490 frag_shader_list = &vert_shader_list[prog->NumShaders];
1492 unsigned min_version = UINT_MAX;
1493 unsigned max_version = 0;
1494 for (unsigned i = 0; i < prog->NumShaders; i++) {
1495 min_version = MIN2(min_version, prog->Shaders[i]->Version);
1496 max_version = MAX2(max_version, prog->Shaders[i]->Version);
1498 switch (prog->Shaders[i]->Type) {
1499 case GL_VERTEX_SHADER:
1500 vert_shader_list[num_vert_shaders] = prog->Shaders[i];
1503 case GL_FRAGMENT_SHADER:
1504 frag_shader_list[num_frag_shaders] = prog->Shaders[i];
1507 case GL_GEOMETRY_SHADER:
1508 /* FINISHME: Support geometry shaders. */
1509 assert(prog->Shaders[i]->Type != GL_GEOMETRY_SHADER);
1514 /* Previous to GLSL version 1.30, different compilation units could mix and
1515 * match shading language versions. With GLSL 1.30 and later, the versions
1516 * of all shaders must match.
1518 assert(min_version >= 100);
1519 assert(max_version <= 130);
1520 if ((max_version >= 130 || min_version == 100)
1521 && min_version != max_version) {
1522 linker_error_printf(prog, "all shaders must use same shading "
1523 "language version\n");
1527 prog->Version = max_version;
1529 for (unsigned int i = 0; i < MESA_SHADER_TYPES; i++) {
1530 if (prog->_LinkedShaders[i] != NULL)
1531 ctx->Driver.DeleteShader(ctx, prog->_LinkedShaders[i]);
1533 prog->_LinkedShaders[i] = NULL;
1536 /* Link all shaders for a particular stage and validate the result.
1538 if (num_vert_shaders > 0) {
1539 gl_shader *const sh =
1540 link_intrastage_shaders(mem_ctx, ctx, prog, vert_shader_list,
1546 if (!validate_vertex_shader_executable(prog, sh))
1549 _mesa_reference_shader(ctx, &prog->_LinkedShaders[MESA_SHADER_VERTEX],
1553 if (num_frag_shaders > 0) {
1554 gl_shader *const sh =
1555 link_intrastage_shaders(mem_ctx, ctx, prog, frag_shader_list,
1561 if (!validate_fragment_shader_executable(prog, sh))
1564 _mesa_reference_shader(ctx, &prog->_LinkedShaders[MESA_SHADER_FRAGMENT],
1568 /* Here begins the inter-stage linking phase. Some initial validation is
1569 * performed, then locations are assigned for uniforms, attributes, and
1572 if (cross_validate_uniforms(prog)) {
1575 for (prev = 0; prev < MESA_SHADER_TYPES; prev++) {
1576 if (prog->_LinkedShaders[prev] != NULL)
1580 /* Validate the inputs of each stage with the output of the preceeding
1583 for (unsigned i = prev + 1; i < MESA_SHADER_TYPES; i++) {
1584 if (prog->_LinkedShaders[i] == NULL)
1587 if (!cross_validate_outputs_to_inputs(prog,
1588 prog->_LinkedShaders[prev],
1589 prog->_LinkedShaders[i]))
1595 prog->LinkStatus = true;
1598 /* Do common optimization before assigning storage for attributes,
1599 * uniforms, and varyings. Later optimization could possibly make
1600 * some of that unused.
1602 for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
1603 if (prog->_LinkedShaders[i] == NULL)
1606 while (do_common_optimization(prog->_LinkedShaders[i]->ir, true, 32))
1610 update_array_sizes(prog);
1612 assign_uniform_locations(prog);
1614 if (prog->_LinkedShaders[MESA_SHADER_VERTEX] != NULL) {
1615 /* FINISHME: The value of the max_attribute_index parameter is
1616 * FINISHME: implementation dependent based on the value of
1617 * FINISHME: GL_MAX_VERTEX_ATTRIBS. GL_MAX_VERTEX_ATTRIBS must be
1618 * FINISHME: at least 16, so hardcode 16 for now.
1620 if (!assign_attribute_locations(prog, 16)) {
1621 prog->LinkStatus = false;
1627 for (prev = 0; prev < MESA_SHADER_TYPES; prev++) {
1628 if (prog->_LinkedShaders[prev] != NULL)
1632 for (unsigned i = prev + 1; i < MESA_SHADER_TYPES; i++) {
1633 if (prog->_LinkedShaders[i] == NULL)
1636 assign_varying_locations(prog,
1637 prog->_LinkedShaders[prev],
1638 prog->_LinkedShaders[i]);
1642 if (prog->_LinkedShaders[MESA_SHADER_VERTEX] != NULL) {
1643 demote_shader_inputs_and_outputs(prog->_LinkedShaders[MESA_SHADER_VERTEX],
1647 if (prog->_LinkedShaders[MESA_SHADER_GEOMETRY] != NULL) {
1648 gl_shader *const sh = prog->_LinkedShaders[MESA_SHADER_GEOMETRY];
1650 demote_shader_inputs_and_outputs(sh, ir_var_in);
1651 demote_shader_inputs_and_outputs(sh, ir_var_inout);
1652 demote_shader_inputs_and_outputs(sh, ir_var_out);
1655 if (prog->_LinkedShaders[MESA_SHADER_FRAGMENT] != NULL) {
1656 gl_shader *const sh = prog->_LinkedShaders[MESA_SHADER_FRAGMENT];
1658 demote_shader_inputs_and_outputs(sh, ir_var_in);
1661 /* FINISHME: Assign fragment shader output locations. */
1664 free(vert_shader_list);
1666 for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
1667 if (prog->_LinkedShaders[i] == NULL)
1670 /* Retain any live IR, but trash the rest. */
1671 reparent_ir(prog->_LinkedShaders[i]->ir, prog->_LinkedShaders[i]->ir);
1674 talloc_free(mem_ctx);