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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 (var->type->length != 0) {
360 existing->type = var->type;
363 linker_error_printf(prog, "%s `%s' declared as type "
364 "`%s' and type `%s'\n",
366 var->name, var->type->name,
367 existing->type->name);
372 if (var->explicit_location) {
373 if (existing->explicit_location
374 && (var->location != existing->location)) {
375 linker_error_printf(prog, "explicit locations for %s "
376 "`%s' have differing values\n",
377 mode_string(var), var->name);
381 existing->location = var->location;
382 existing->explicit_location = true;
385 /* FINISHME: Handle non-constant initializers.
387 if (var->constant_value != NULL) {
388 if (existing->constant_value != NULL) {
389 if (!var->constant_value->has_value(existing->constant_value)) {
390 linker_error_printf(prog, "initializers for %s "
391 "`%s' have differing values\n",
392 mode_string(var), var->name);
396 /* If the first-seen instance of a particular uniform did not
397 * have an initializer but a later instance does, copy the
398 * initializer to the version stored in the symbol table.
400 /* FINISHME: This is wrong. The constant_value field should
401 * FINISHME: not be modified! Imagine a case where a shader
402 * FINISHME: without an initializer is linked in two different
403 * FINISHME: programs with shaders that have differing
404 * FINISHME: initializers. Linking with the first will
405 * FINISHME: modify the shader, and linking with the second
406 * FINISHME: will fail.
408 existing->constant_value =
409 var->constant_value->clone(talloc_parent(existing), NULL);
412 if (existing->invariant != var->invariant) {
413 linker_error_printf(prog, "declarations for %s `%s' have "
414 "mismatching invariant qualifiers\n",
415 mode_string(var), var->name);
418 if (existing->centroid != var->centroid) {
419 linker_error_printf(prog, "declarations for %s `%s' have "
420 "mismatching centroid qualifiers\n",
421 mode_string(var), var->name);
425 variables.add_variable(var);
434 * Perform validation of uniforms used across multiple shader stages
437 cross_validate_uniforms(struct gl_shader_program *prog)
439 return cross_validate_globals(prog, prog->_LinkedShaders,
440 MESA_SHADER_TYPES, true);
445 * Validate that outputs from one stage match inputs of another
448 cross_validate_outputs_to_inputs(struct gl_shader_program *prog,
449 gl_shader *producer, gl_shader *consumer)
451 glsl_symbol_table parameters;
452 /* FINISHME: Figure these out dynamically. */
453 const char *const producer_stage = "vertex";
454 const char *const consumer_stage = "fragment";
456 /* Find all shader outputs in the "producer" stage.
458 foreach_list(node, producer->ir) {
459 ir_variable *const var = ((ir_instruction *) node)->as_variable();
461 /* FINISHME: For geometry shaders, this should also look for inout
462 * FINISHME: variables.
464 if ((var == NULL) || (var->mode != ir_var_out))
467 parameters.add_variable(var);
471 /* Find all shader inputs in the "consumer" stage. Any variables that have
472 * matching outputs already in the symbol table must have the same type and
475 foreach_list(node, consumer->ir) {
476 ir_variable *const input = ((ir_instruction *) node)->as_variable();
478 /* FINISHME: For geometry shaders, this should also look for inout
479 * FINISHME: variables.
481 if ((input == NULL) || (input->mode != ir_var_in))
484 ir_variable *const output = parameters.get_variable(input->name);
485 if (output != NULL) {
486 /* Check that the types match between stages.
488 if (input->type != output->type) {
489 /* There is a bit of a special case for gl_TexCoord. This
490 * built-in is unsized by default. Appliations that variable
491 * access it must redeclare it with a size. There is some
492 * language in the GLSL spec that implies the fragment shader
493 * and vertex shader do not have to agree on this size. Other
494 * driver behave this way, and one or two applications seem to
497 * Neither declaration needs to be modified here because the array
498 * sizes are fixed later when update_array_sizes is called.
500 * From page 48 (page 54 of the PDF) of the GLSL 1.10 spec:
502 * "Unlike user-defined varying variables, the built-in
503 * varying variables don't have a strict one-to-one
504 * correspondence between the vertex language and the
505 * fragment language."
507 if (!output->type->is_array()
508 || (strncmp("gl_", output->name, 3) != 0)) {
509 linker_error_printf(prog,
510 "%s shader output `%s' declared as "
511 "type `%s', but %s shader input declared "
513 producer_stage, output->name,
515 consumer_stage, input->type->name);
520 /* Check that all of the qualifiers match between stages.
522 if (input->centroid != output->centroid) {
523 linker_error_printf(prog,
524 "%s shader output `%s' %s centroid qualifier, "
525 "but %s shader input %s centroid qualifier\n",
528 (output->centroid) ? "has" : "lacks",
530 (input->centroid) ? "has" : "lacks");
534 if (input->invariant != output->invariant) {
535 linker_error_printf(prog,
536 "%s shader output `%s' %s invariant qualifier, "
537 "but %s shader input %s invariant qualifier\n",
540 (output->invariant) ? "has" : "lacks",
542 (input->invariant) ? "has" : "lacks");
546 if (input->interpolation != output->interpolation) {
547 linker_error_printf(prog,
548 "%s shader output `%s' specifies %s "
549 "interpolation qualifier, "
550 "but %s shader input specifies %s "
551 "interpolation qualifier\n",
554 output->interpolation_string(),
556 input->interpolation_string());
567 * Populates a shaders symbol table with all global declarations
570 populate_symbol_table(gl_shader *sh)
572 sh->symbols = new(sh) glsl_symbol_table;
574 foreach_list(node, sh->ir) {
575 ir_instruction *const inst = (ir_instruction *) node;
579 if ((func = inst->as_function()) != NULL) {
580 sh->symbols->add_function(func);
581 } else if ((var = inst->as_variable()) != NULL) {
582 sh->symbols->add_variable(var);
589 * Remap variables referenced in an instruction tree
591 * This is used when instruction trees are cloned from one shader and placed in
592 * another. These trees will contain references to \c ir_variable nodes that
593 * do not exist in the target shader. This function finds these \c ir_variable
594 * references and replaces the references with matching variables in the target
597 * If there is no matching variable in the target shader, a clone of the
598 * \c ir_variable is made and added to the target shader. The new variable is
599 * added to \b both the instruction stream and the symbol table.
601 * \param inst IR tree that is to be processed.
602 * \param symbols Symbol table containing global scope symbols in the
604 * \param instructions Instruction stream where new variable declarations
608 remap_variables(ir_instruction *inst, struct gl_shader *target,
611 class remap_visitor : public ir_hierarchical_visitor {
613 remap_visitor(struct gl_shader *target,
616 this->target = target;
617 this->symbols = target->symbols;
618 this->instructions = target->ir;
622 virtual ir_visitor_status visit(ir_dereference_variable *ir)
624 if (ir->var->mode == ir_var_temporary) {
625 ir_variable *var = (ir_variable *) hash_table_find(temps, ir->var);
629 return visit_continue;
632 ir_variable *const existing =
633 this->symbols->get_variable(ir->var->name);
634 if (existing != NULL)
637 ir_variable *copy = ir->var->clone(this->target, NULL);
639 this->symbols->add_variable(copy);
640 this->instructions->push_head(copy);
644 return visit_continue;
648 struct gl_shader *target;
649 glsl_symbol_table *symbols;
650 exec_list *instructions;
654 remap_visitor v(target, temps);
661 * Move non-declarations from one instruction stream to another
663 * The intended usage pattern of this function is to pass the pointer to the
664 * head sentinel of a list (i.e., a pointer to the list cast to an \c exec_node
665 * pointer) for \c last and \c false for \c make_copies on the first
666 * call. Successive calls pass the return value of the previous call for
667 * \c last and \c true for \c make_copies.
669 * \param instructions Source instruction stream
670 * \param last Instruction after which new instructions should be
671 * inserted in the target instruction stream
672 * \param make_copies Flag selecting whether instructions in \c instructions
673 * should be copied (via \c ir_instruction::clone) into the
674 * target list or moved.
677 * The new "last" instruction in the target instruction stream. This pointer
678 * is suitable for use as the \c last parameter of a later call to this
682 move_non_declarations(exec_list *instructions, exec_node *last,
683 bool make_copies, gl_shader *target)
685 hash_table *temps = NULL;
688 temps = hash_table_ctor(0, hash_table_pointer_hash,
689 hash_table_pointer_compare);
691 foreach_list_safe(node, instructions) {
692 ir_instruction *inst = (ir_instruction *) node;
694 if (inst->as_function())
697 ir_variable *var = inst->as_variable();
698 if ((var != NULL) && (var->mode != ir_var_temporary))
701 assert(inst->as_assignment()
702 || ((var != NULL) && (var->mode == ir_var_temporary)));
705 inst = inst->clone(target, NULL);
708 hash_table_insert(temps, inst, var);
710 remap_variables(inst, target, temps);
715 last->insert_after(inst);
720 hash_table_dtor(temps);
726 * Get the function signature for main from a shader
728 static ir_function_signature *
729 get_main_function_signature(gl_shader *sh)
731 ir_function *const f = sh->symbols->get_function("main");
733 exec_list void_parameters;
735 /* Look for the 'void main()' signature and ensure that it's defined.
736 * This keeps the linker from accidentally pick a shader that just
737 * contains a prototype for main.
739 * We don't have to check for multiple definitions of main (in multiple
740 * shaders) because that would have already been caught above.
742 ir_function_signature *sig = f->matching_signature(&void_parameters);
743 if ((sig != NULL) && sig->is_defined) {
753 * Combine a group of shaders for a single stage to generate a linked shader
756 * If this function is supplied a single shader, it is cloned, and the new
757 * shader is returned.
759 static struct gl_shader *
760 link_intrastage_shaders(void *mem_ctx,
761 struct gl_context *ctx,
762 struct gl_shader_program *prog,
763 struct gl_shader **shader_list,
764 unsigned num_shaders)
766 /* Check that global variables defined in multiple shaders are consistent.
768 if (!cross_validate_globals(prog, shader_list, num_shaders, false))
771 /* Check that there is only a single definition of each function signature
772 * across all shaders.
774 for (unsigned i = 0; i < (num_shaders - 1); i++) {
775 foreach_list(node, shader_list[i]->ir) {
776 ir_function *const f = ((ir_instruction *) node)->as_function();
781 for (unsigned j = i + 1; j < num_shaders; j++) {
782 ir_function *const other =
783 shader_list[j]->symbols->get_function(f->name);
785 /* If the other shader has no function (and therefore no function
786 * signatures) with the same name, skip to the next shader.
791 foreach_iter (exec_list_iterator, iter, *f) {
792 ir_function_signature *sig =
793 (ir_function_signature *) iter.get();
795 if (!sig->is_defined || sig->is_builtin)
798 ir_function_signature *other_sig =
799 other->exact_matching_signature(& sig->parameters);
801 if ((other_sig != NULL) && other_sig->is_defined
802 && !other_sig->is_builtin) {
803 linker_error_printf(prog,
804 "function `%s' is multiply defined",
813 /* Find the shader that defines main, and make a clone of it.
815 * Starting with the clone, search for undefined references. If one is
816 * found, find the shader that defines it. Clone the reference and add
817 * it to the shader. Repeat until there are no undefined references or
818 * until a reference cannot be resolved.
820 gl_shader *main = NULL;
821 for (unsigned i = 0; i < num_shaders; i++) {
822 if (get_main_function_signature(shader_list[i]) != NULL) {
823 main = shader_list[i];
829 linker_error_printf(prog, "%s shader lacks `main'\n",
830 (shader_list[0]->Type == GL_VERTEX_SHADER)
831 ? "vertex" : "fragment");
835 gl_shader *linked = ctx->Driver.NewShader(NULL, 0, main->Type);
836 linked->ir = new(linked) exec_list;
837 clone_ir_list(mem_ctx, linked->ir, main->ir);
839 populate_symbol_table(linked);
841 /* The a pointer to the main function in the final linked shader (i.e., the
842 * copy of the original shader that contained the main function).
844 ir_function_signature *const main_sig = get_main_function_signature(linked);
846 /* Move any instructions other than variable declarations or function
847 * declarations into main.
849 exec_node *insertion_point =
850 move_non_declarations(linked->ir, (exec_node *) &main_sig->body, false,
853 for (unsigned i = 0; i < num_shaders; i++) {
854 if (shader_list[i] == main)
857 insertion_point = move_non_declarations(shader_list[i]->ir,
858 insertion_point, true, linked);
861 /* Resolve initializers for global variables in the linked shader.
863 unsigned num_linking_shaders = num_shaders;
864 for (unsigned i = 0; i < num_shaders; i++)
865 num_linking_shaders += shader_list[i]->num_builtins_to_link;
867 gl_shader **linking_shaders =
868 (gl_shader **) calloc(num_linking_shaders, sizeof(gl_shader *));
870 memcpy(linking_shaders, shader_list,
871 sizeof(linking_shaders[0]) * num_shaders);
873 unsigned idx = num_shaders;
874 for (unsigned i = 0; i < num_shaders; i++) {
875 memcpy(&linking_shaders[idx], shader_list[i]->builtins_to_link,
876 sizeof(linking_shaders[0]) * shader_list[i]->num_builtins_to_link);
877 idx += shader_list[i]->num_builtins_to_link;
880 assert(idx == num_linking_shaders);
882 if (!link_function_calls(prog, linked, linking_shaders,
883 num_linking_shaders)) {
884 ctx->Driver.DeleteShader(ctx, linked);
888 free(linking_shaders);
890 /* Make a pass over all variable declarations to ensure that arrays with
891 * unspecified sizes have a size specified. The size is inferred from the
892 * max_array_access field.
894 if (linked != NULL) {
895 class array_sizing_visitor : public ir_hierarchical_visitor {
897 virtual ir_visitor_status visit(ir_variable *var)
899 if (var->type->is_array() && (var->type->length == 0)) {
900 const glsl_type *type =
901 glsl_type::get_array_instance(var->type->fields.array,
902 var->max_array_access);
904 assert(type != NULL);
908 return visit_continue;
919 struct uniform_node {
921 struct gl_uniform *u;
926 * Update the sizes of linked shader uniform arrays to the maximum
929 * From page 81 (page 95 of the PDF) of the OpenGL 2.1 spec:
931 * If one or more elements of an array are active,
932 * GetActiveUniform will return the name of the array in name,
933 * subject to the restrictions listed above. The type of the array
934 * is returned in type. The size parameter contains the highest
935 * array element index used, plus one. The compiler or linker
936 * determines the highest index used. There will be only one
937 * active uniform reported by the GL per uniform array.
941 update_array_sizes(struct gl_shader_program *prog)
943 for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
944 if (prog->_LinkedShaders[i] == NULL)
947 foreach_list(node, prog->_LinkedShaders[i]->ir) {
948 ir_variable *const var = ((ir_instruction *) node)->as_variable();
950 if ((var == NULL) || (var->mode != ir_var_uniform &&
951 var->mode != ir_var_in &&
952 var->mode != ir_var_out) ||
953 !var->type->is_array())
956 unsigned int size = var->max_array_access;
957 for (unsigned j = 0; j < MESA_SHADER_TYPES; j++) {
958 if (prog->_LinkedShaders[j] == NULL)
961 foreach_list(node2, prog->_LinkedShaders[j]->ir) {
962 ir_variable *other_var = ((ir_instruction *) node2)->as_variable();
966 if (strcmp(var->name, other_var->name) == 0 &&
967 other_var->max_array_access > size) {
968 size = other_var->max_array_access;
973 if (size + 1 != var->type->fields.array->length) {
974 var->type = glsl_type::get_array_instance(var->type->fields.array,
976 /* FINISHME: We should update the types of array
977 * dereferences of this variable now.
985 add_uniform(void *mem_ctx, exec_list *uniforms, struct hash_table *ht,
986 const char *name, const glsl_type *type, GLenum shader_type,
987 unsigned *next_shader_pos, unsigned *total_uniforms)
989 if (type->is_record()) {
990 for (unsigned int i = 0; i < type->length; i++) {
991 const glsl_type *field_type = type->fields.structure[i].type;
992 char *field_name = talloc_asprintf(mem_ctx, "%s.%s", name,
993 type->fields.structure[i].name);
995 add_uniform(mem_ctx, uniforms, ht, field_name, field_type,
996 shader_type, next_shader_pos, total_uniforms);
999 uniform_node *n = (uniform_node *) hash_table_find(ht, name);
1000 unsigned int vec4_slots;
1001 const glsl_type *array_elem_type = NULL;
1003 if (type->is_array()) {
1004 array_elem_type = type->fields.array;
1005 /* Array of structures. */
1006 if (array_elem_type->is_record()) {
1007 for (unsigned int i = 0; i < type->length; i++) {
1008 char *elem_name = talloc_asprintf(mem_ctx, "%s[%d]", name, i);
1009 add_uniform(mem_ctx, uniforms, ht, elem_name, array_elem_type,
1010 shader_type, next_shader_pos, total_uniforms);
1016 /* Fix the storage size of samplers at 1 vec4 each. Be sure to pad out
1017 * vectors to vec4 slots.
1019 if (type->is_array()) {
1020 if (array_elem_type->is_sampler())
1021 vec4_slots = type->length;
1023 vec4_slots = type->length * array_elem_type->matrix_columns;
1024 } else if (type->is_sampler()) {
1027 vec4_slots = type->matrix_columns;
1031 n = (uniform_node *) calloc(1, sizeof(struct uniform_node));
1032 n->u = (gl_uniform *) calloc(1, sizeof(struct gl_uniform));
1033 n->slots = vec4_slots;
1035 n->u->Name = strdup(name);
1040 (*total_uniforms)++;
1042 hash_table_insert(ht, n, name);
1043 uniforms->push_tail(& n->link);
1046 switch (shader_type) {
1047 case GL_VERTEX_SHADER:
1048 n->u->VertPos = *next_shader_pos;
1050 case GL_FRAGMENT_SHADER:
1051 n->u->FragPos = *next_shader_pos;
1053 case GL_GEOMETRY_SHADER:
1054 n->u->GeomPos = *next_shader_pos;
1058 (*next_shader_pos) += vec4_slots;
1063 assign_uniform_locations(struct gl_shader_program *prog)
1067 unsigned total_uniforms = 0;
1068 hash_table *ht = hash_table_ctor(32, hash_table_string_hash,
1069 hash_table_string_compare);
1070 void *mem_ctx = talloc_new(NULL);
1072 for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
1073 if (prog->_LinkedShaders[i] == NULL)
1076 unsigned next_position = 0;
1078 foreach_list(node, prog->_LinkedShaders[i]->ir) {
1079 ir_variable *const var = ((ir_instruction *) node)->as_variable();
1081 if ((var == NULL) || (var->mode != ir_var_uniform))
1084 if (strncmp(var->name, "gl_", 3) == 0) {
1085 /* At the moment, we don't allocate uniform locations for
1086 * builtin uniforms. It's permitted by spec, and we'll
1087 * likely switch to doing that at some point, but not yet.
1092 var->location = next_position;
1093 add_uniform(mem_ctx, &uniforms, ht, var->name, var->type,
1094 prog->_LinkedShaders[i]->Type,
1095 &next_position, &total_uniforms);
1099 talloc_free(mem_ctx);
1101 gl_uniform_list *ul = (gl_uniform_list *)
1102 calloc(1, sizeof(gl_uniform_list));
1104 ul->Size = total_uniforms;
1105 ul->NumUniforms = total_uniforms;
1106 ul->Uniforms = (gl_uniform *) calloc(total_uniforms, sizeof(gl_uniform));
1110 for (uniform_node *node = (uniform_node *) uniforms.head
1111 ; node->link.next != NULL
1113 next = (uniform_node *) node->link.next;
1115 node->link.remove();
1116 memcpy(&ul->Uniforms[idx], node->u, sizeof(gl_uniform));
1123 hash_table_dtor(ht);
1125 prog->Uniforms = ul;
1130 * Find a contiguous set of available bits in a bitmask
1132 * \param used_mask Bits representing used (1) and unused (0) locations
1133 * \param needed_count Number of contiguous bits needed.
1136 * Base location of the available bits on success or -1 on failure.
1139 find_available_slots(unsigned used_mask, unsigned needed_count)
1141 unsigned needed_mask = (1 << needed_count) - 1;
1142 const int max_bit_to_test = (8 * sizeof(used_mask)) - needed_count;
1144 /* The comparison to 32 is redundant, but without it GCC emits "warning:
1145 * cannot optimize possibly infinite loops" for the loop below.
1147 if ((needed_count == 0) || (max_bit_to_test < 0) || (max_bit_to_test > 32))
1150 for (int i = 0; i <= max_bit_to_test; i++) {
1151 if ((needed_mask & ~used_mask) == needed_mask)
1162 assign_attribute_locations(gl_shader_program *prog, unsigned max_attribute_index)
1164 /* Mark invalid attribute locations as being used.
1166 unsigned used_locations = (max_attribute_index >= 32)
1167 ? ~0 : ~((1 << max_attribute_index) - 1);
1169 gl_shader *const sh = prog->_LinkedShaders[0];
1170 assert(sh->Type == GL_VERTEX_SHADER);
1172 /* Operate in a total of four passes.
1174 * 1. Invalidate the location assignments for all vertex shader inputs.
1176 * 2. Assign locations for inputs that have user-defined (via
1177 * glBindVertexAttribLocation) locatoins.
1179 * 3. Sort the attributes without assigned locations by number of slots
1180 * required in decreasing order. Fragmentation caused by attribute
1181 * locations assigned by the application may prevent large attributes
1182 * from having enough contiguous space.
1184 * 4. Assign locations to any inputs without assigned locations.
1187 invalidate_variable_locations(sh, ir_var_in, VERT_ATTRIB_GENERIC0);
1189 if (prog->Attributes != NULL) {
1190 for (unsigned i = 0; i < prog->Attributes->NumParameters; i++) {
1191 ir_variable *const var =
1192 sh->symbols->get_variable(prog->Attributes->Parameters[i].Name);
1194 /* Note: attributes that occupy multiple slots, such as arrays or
1195 * matrices, may appear in the attrib array multiple times.
1197 if ((var == NULL) || (var->location != -1))
1200 /* From page 61 of the OpenGL 4.0 spec:
1202 * "LinkProgram will fail if the attribute bindings assigned by
1203 * BindAttribLocation do not leave not enough space to assign a
1204 * location for an active matrix attribute or an active attribute
1205 * array, both of which require multiple contiguous generic
1208 * Previous versions of the spec contain similar language but omit the
1209 * bit about attribute arrays.
1211 * Page 61 of the OpenGL 4.0 spec also says:
1213 * "It is possible for an application to bind more than one
1214 * attribute name to the same location. This is referred to as
1215 * aliasing. This will only work if only one of the aliased
1216 * attributes is active in the executable program, or if no path
1217 * through the shader consumes more than one attribute of a set
1218 * of attributes aliased to the same location. A link error can
1219 * occur if the linker determines that every path through the
1220 * shader consumes multiple aliased attributes, but
1221 * implementations are not required to generate an error in this
1224 * These two paragraphs are either somewhat contradictory, or I don't
1225 * fully understand one or both of them.
1227 /* FINISHME: The code as currently written does not support attribute
1228 * FINISHME: location aliasing (see comment above).
1230 const int attr = prog->Attributes->Parameters[i].StateIndexes[0];
1231 const unsigned slots = count_attribute_slots(var->type);
1233 /* Mask representing the contiguous slots that will be used by this
1236 const unsigned use_mask = (1 << slots) - 1;
1238 /* Generate a link error if the set of bits requested for this
1239 * attribute overlaps any previously allocated bits.
1241 if ((~(use_mask << attr) & used_locations) != used_locations) {
1242 linker_error_printf(prog,
1243 "insufficient contiguous attribute locations "
1244 "available for vertex shader input `%s'",
1249 var->location = VERT_ATTRIB_GENERIC0 + attr;
1250 used_locations |= (use_mask << attr);
1254 /* Temporary storage for the set of attributes that need locations assigned.
1260 /* Used below in the call to qsort. */
1261 static int compare(const void *a, const void *b)
1263 const temp_attr *const l = (const temp_attr *) a;
1264 const temp_attr *const r = (const temp_attr *) b;
1266 /* Reversed because we want a descending order sort below. */
1267 return r->slots - l->slots;
1271 unsigned num_attr = 0;
1273 foreach_list(node, sh->ir) {
1274 ir_variable *const var = ((ir_instruction *) node)->as_variable();
1276 if ((var == NULL) || (var->mode != ir_var_in))
1279 if (var->explicit_location) {
1280 const unsigned slots = count_attribute_slots(var->type);
1281 const unsigned use_mask = (1 << slots) - 1;
1282 const int attr = var->location - VERT_ATTRIB_GENERIC0;
1284 if ((var->location >= (int)(max_attribute_index + VERT_ATTRIB_GENERIC0))
1285 || (var->location < 0)) {
1286 linker_error_printf(prog,
1287 "invalid explicit location %d specified for "
1289 (var->location < 0) ? var->location : attr,
1292 } else if (var->location >= VERT_ATTRIB_GENERIC0) {
1293 used_locations |= (use_mask << attr);
1297 /* The location was explicitly assigned, nothing to do here.
1299 if (var->location != -1)
1302 to_assign[num_attr].slots = count_attribute_slots(var->type);
1303 to_assign[num_attr].var = var;
1307 /* If all of the attributes were assigned locations by the application (or
1308 * are built-in attributes with fixed locations), return early. This should
1309 * be the common case.
1314 qsort(to_assign, num_attr, sizeof(to_assign[0]), temp_attr::compare);
1316 /* VERT_ATTRIB_GENERIC0 is a psdueo-alias for VERT_ATTRIB_POS. It can only
1317 * be explicitly assigned by via glBindAttribLocation. Mark it as reserved
1318 * to prevent it from being automatically allocated below.
1320 find_deref_visitor find("gl_Vertex");
1322 if (find.variable_found())
1323 used_locations |= (1 << 0);
1325 for (unsigned i = 0; i < num_attr; i++) {
1326 /* Mask representing the contiguous slots that will be used by this
1329 const unsigned use_mask = (1 << to_assign[i].slots) - 1;
1331 int location = find_available_slots(used_locations, to_assign[i].slots);
1334 linker_error_printf(prog,
1335 "insufficient contiguous attribute locations "
1336 "available for vertex shader input `%s'",
1337 to_assign[i].var->name);
1341 to_assign[i].var->location = VERT_ATTRIB_GENERIC0 + location;
1342 used_locations |= (use_mask << location);
1350 * Demote shader inputs and outputs that are not used in other stages
1353 demote_shader_inputs_and_outputs(gl_shader *sh, enum ir_variable_mode mode)
1355 foreach_list(node, sh->ir) {
1356 ir_variable *const var = ((ir_instruction *) node)->as_variable();
1358 if ((var == NULL) || (var->mode != int(mode)))
1361 /* A shader 'in' or 'out' variable is only really an input or output if
1362 * its value is used by other shader stages. This will cause the variable
1363 * to have a location assigned.
1365 if (var->location == -1) {
1366 var->mode = ir_var_auto;
1373 assign_varying_locations(struct gl_shader_program *prog,
1374 gl_shader *producer, gl_shader *consumer)
1376 /* FINISHME: Set dynamically when geometry shader support is added. */
1377 unsigned output_index = VERT_RESULT_VAR0;
1378 unsigned input_index = FRAG_ATTRIB_VAR0;
1380 /* Operate in a total of three passes.
1382 * 1. Assign locations for any matching inputs and outputs.
1384 * 2. Mark output variables in the producer that do not have locations as
1385 * not being outputs. This lets the optimizer eliminate them.
1387 * 3. Mark input variables in the consumer that do not have locations as
1388 * not being inputs. This lets the optimizer eliminate them.
1391 invalidate_variable_locations(producer, ir_var_out, VERT_RESULT_VAR0);
1392 invalidate_variable_locations(consumer, ir_var_in, FRAG_ATTRIB_VAR0);
1394 foreach_list(node, producer->ir) {
1395 ir_variable *const output_var = ((ir_instruction *) node)->as_variable();
1397 if ((output_var == NULL) || (output_var->mode != ir_var_out)
1398 || (output_var->location != -1))
1401 ir_variable *const input_var =
1402 consumer->symbols->get_variable(output_var->name);
1404 if ((input_var == NULL) || (input_var->mode != ir_var_in))
1407 assert(input_var->location == -1);
1409 output_var->location = output_index;
1410 input_var->location = input_index;
1412 /* FINISHME: Support for "varying" records in GLSL 1.50. */
1413 assert(!output_var->type->is_record());
1415 if (output_var->type->is_array()) {
1416 const unsigned slots = output_var->type->length
1417 * output_var->type->fields.array->matrix_columns;
1419 output_index += slots;
1420 input_index += slots;
1422 const unsigned slots = output_var->type->matrix_columns;
1424 output_index += slots;
1425 input_index += slots;
1429 foreach_list(node, consumer->ir) {
1430 ir_variable *const var = ((ir_instruction *) node)->as_variable();
1432 if ((var == NULL) || (var->mode != ir_var_in))
1435 if (var->location == -1) {
1436 if (prog->Version <= 120) {
1437 /* On page 25 (page 31 of the PDF) of the GLSL 1.20 spec:
1439 * Only those varying variables used (i.e. read) in
1440 * the fragment shader executable must be written to
1441 * by the vertex shader executable; declaring
1442 * superfluous varying variables in a vertex shader is
1445 * We interpret this text as meaning that the VS must
1446 * write the variable for the FS to read it. See
1447 * "glsl1-varying read but not written" in piglit.
1450 linker_error_printf(prog, "fragment shader varying %s not written "
1451 "by vertex shader\n.", var->name);
1452 prog->LinkStatus = false;
1455 /* An 'in' variable is only really a shader input if its
1456 * value is written by the previous stage.
1458 var->mode = ir_var_auto;
1465 link_shaders(struct gl_context *ctx, struct gl_shader_program *prog)
1467 void *mem_ctx = talloc_init("temporary linker context");
1469 prog->LinkStatus = false;
1470 prog->Validated = false;
1471 prog->_Used = false;
1473 if (prog->InfoLog != NULL)
1474 talloc_free(prog->InfoLog);
1476 prog->InfoLog = talloc_strdup(NULL, "");
1478 /* Separate the shaders into groups based on their type.
1480 struct gl_shader **vert_shader_list;
1481 unsigned num_vert_shaders = 0;
1482 struct gl_shader **frag_shader_list;
1483 unsigned num_frag_shaders = 0;
1485 vert_shader_list = (struct gl_shader **)
1486 calloc(2 * prog->NumShaders, sizeof(struct gl_shader *));
1487 frag_shader_list = &vert_shader_list[prog->NumShaders];
1489 unsigned min_version = UINT_MAX;
1490 unsigned max_version = 0;
1491 for (unsigned i = 0; i < prog->NumShaders; i++) {
1492 min_version = MIN2(min_version, prog->Shaders[i]->Version);
1493 max_version = MAX2(max_version, prog->Shaders[i]->Version);
1495 switch (prog->Shaders[i]->Type) {
1496 case GL_VERTEX_SHADER:
1497 vert_shader_list[num_vert_shaders] = prog->Shaders[i];
1500 case GL_FRAGMENT_SHADER:
1501 frag_shader_list[num_frag_shaders] = prog->Shaders[i];
1504 case GL_GEOMETRY_SHADER:
1505 /* FINISHME: Support geometry shaders. */
1506 assert(prog->Shaders[i]->Type != GL_GEOMETRY_SHADER);
1511 /* Previous to GLSL version 1.30, different compilation units could mix and
1512 * match shading language versions. With GLSL 1.30 and later, the versions
1513 * of all shaders must match.
1515 assert(min_version >= 100);
1516 assert(max_version <= 130);
1517 if ((max_version >= 130 || min_version == 100)
1518 && min_version != max_version) {
1519 linker_error_printf(prog, "all shaders must use same shading "
1520 "language version\n");
1524 prog->Version = max_version;
1526 for (unsigned int i = 0; i < MESA_SHADER_TYPES; i++) {
1527 if (prog->_LinkedShaders[i] != NULL)
1528 ctx->Driver.DeleteShader(ctx, prog->_LinkedShaders[i]);
1530 prog->_LinkedShaders[i] = NULL;
1533 /* Link all shaders for a particular stage and validate the result.
1535 if (num_vert_shaders > 0) {
1536 gl_shader *const sh =
1537 link_intrastage_shaders(mem_ctx, ctx, prog, vert_shader_list,
1543 if (!validate_vertex_shader_executable(prog, sh))
1546 _mesa_reference_shader(ctx, &prog->_LinkedShaders[MESA_SHADER_VERTEX],
1550 if (num_frag_shaders > 0) {
1551 gl_shader *const sh =
1552 link_intrastage_shaders(mem_ctx, ctx, prog, frag_shader_list,
1558 if (!validate_fragment_shader_executable(prog, sh))
1561 _mesa_reference_shader(ctx, &prog->_LinkedShaders[MESA_SHADER_FRAGMENT],
1565 /* Here begins the inter-stage linking phase. Some initial validation is
1566 * performed, then locations are assigned for uniforms, attributes, and
1569 if (cross_validate_uniforms(prog)) {
1572 for (prev = 0; prev < MESA_SHADER_TYPES; prev++) {
1573 if (prog->_LinkedShaders[prev] != NULL)
1577 /* Validate the inputs of each stage with the output of the preceeding
1580 for (unsigned i = prev + 1; i < MESA_SHADER_TYPES; i++) {
1581 if (prog->_LinkedShaders[i] == NULL)
1584 if (!cross_validate_outputs_to_inputs(prog,
1585 prog->_LinkedShaders[prev],
1586 prog->_LinkedShaders[i]))
1592 prog->LinkStatus = true;
1595 /* Do common optimization before assigning storage for attributes,
1596 * uniforms, and varyings. Later optimization could possibly make
1597 * some of that unused.
1599 for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
1600 if (prog->_LinkedShaders[i] == NULL)
1603 while (do_common_optimization(prog->_LinkedShaders[i]->ir, true, 32))
1607 update_array_sizes(prog);
1609 assign_uniform_locations(prog);
1611 if (prog->_LinkedShaders[MESA_SHADER_VERTEX] != NULL) {
1612 /* FINISHME: The value of the max_attribute_index parameter is
1613 * FINISHME: implementation dependent based on the value of
1614 * FINISHME: GL_MAX_VERTEX_ATTRIBS. GL_MAX_VERTEX_ATTRIBS must be
1615 * FINISHME: at least 16, so hardcode 16 for now.
1617 if (!assign_attribute_locations(prog, 16)) {
1618 prog->LinkStatus = false;
1624 for (prev = 0; prev < MESA_SHADER_TYPES; prev++) {
1625 if (prog->_LinkedShaders[prev] != NULL)
1629 for (unsigned i = prev + 1; i < MESA_SHADER_TYPES; i++) {
1630 if (prog->_LinkedShaders[i] == NULL)
1633 assign_varying_locations(prog,
1634 prog->_LinkedShaders[prev],
1635 prog->_LinkedShaders[i]);
1639 if (prog->_LinkedShaders[MESA_SHADER_VERTEX] != NULL) {
1640 demote_shader_inputs_and_outputs(prog->_LinkedShaders[MESA_SHADER_VERTEX],
1644 if (prog->_LinkedShaders[MESA_SHADER_GEOMETRY] != NULL) {
1645 gl_shader *const sh = prog->_LinkedShaders[MESA_SHADER_GEOMETRY];
1647 demote_shader_inputs_and_outputs(sh, ir_var_in);
1648 demote_shader_inputs_and_outputs(sh, ir_var_inout);
1649 demote_shader_inputs_and_outputs(sh, ir_var_out);
1652 if (prog->_LinkedShaders[MESA_SHADER_FRAGMENT] != NULL) {
1653 gl_shader *const sh = prog->_LinkedShaders[MESA_SHADER_FRAGMENT];
1655 demote_shader_inputs_and_outputs(sh, ir_var_in);
1658 /* FINISHME: Assign fragment shader output locations. */
1661 free(vert_shader_list);
1663 for (unsigned i = 0; i < MESA_SHADER_TYPES; i++) {
1664 if (prog->_LinkedShaders[i] == NULL)
1667 /* Retain any live IR, but trash the rest. */
1668 reparent_ir(prog->_LinkedShaders[i]->ir, prog->_LinkedShaders[i]->ir);
1671 talloc_free(mem_ctx);