/* * Copyright © 2013 Intel Corporation * Copyright © 2024 Valve Corporation * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * Software is furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice (including the next * paragraph) shall be included in all copies or substantial portions of the * Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. */ /** * Linker support for GLSL's interface blocks. */ #include "gl_nir_linker.h" #include "linker_util.h" #include "nir.h" #include "main/macros.h" #include "main/shader_types.h" #include "util/hash_table.h" #include "util/u_string.h" /** * Return true if interface members mismatch and its not allowed by GLSL. */ static bool interstage_member_mismatch(struct gl_shader_program *prog, const struct glsl_type *c, const struct glsl_type *p) { if (c->length != p->length) return true; for (unsigned i = 0; i < c->length; i++) { if (c->fields.structure[i].type != p->fields.structure[i].type) return true; if (strcmp(c->fields.structure[i].name, p->fields.structure[i].name) != 0) return true; if (c->fields.structure[i].location != p->fields.structure[i].location) return true; if (c->fields.structure[i].component != p->fields.structure[i].component) return true; if (c->fields.structure[i].patch != p->fields.structure[i].patch) return true; /* From Section 4.5 (Interpolation Qualifiers) of the GLSL 4.40 spec: * * "It is a link-time error if, within the same stage, the * interpolation qualifiers of variables of the same name do not * match." */ if (prog->IsES || prog->GLSL_Version < 440) if (c->fields.structure[i].interpolation != p->fields.structure[i].interpolation) return true; /* From Section 4.3.4 (Input Variables) of the GLSL ES 3.0 spec: * * "The output of the vertex shader and the input of the fragment * shader form an interface. For this interface, vertex shader * output variables and fragment shader input variables of the same * name must match in type and qualification (other than precision * and out matching to in). * * The table in Section 9.2.1 Linked Shaders of the GLSL ES 3.1 spec * says that centroid no longer needs to match for varyings. * * The table in Section 9.2.1 Linked Shaders of the GLSL ES 3.2 spec * says that sample need not match for varyings. */ if (!prog->IsES || prog->GLSL_Version < 310) if (c->fields.structure[i].centroid != p->fields.structure[i].centroid) return true; if (!prog->IsES) if (c->fields.structure[i].sample != p->fields.structure[i].sample) return true; } return false; } static bool is_interface_instance(nir_variable *var) { return glsl_without_array(var->type) == var->interface_type; } /** * Check if two interfaces match, according to intrastage interface matching * rules. If they do, and the first interface uses an unsized array, it will * be updated to reflect the array size declared in the second interface. */ static bool intrastage_match(nir_variable *a, nir_variable *b, struct gl_shader_program *prog, unsigned a_stage, bool match_precision) { /* From section 4.7 "Precision and Precision Qualifiers" in GLSL 4.50: * * "For the purposes of determining if an output from one shader * stage matches an input of the next stage, the precision qualifier * need not match." */ bool interface_type_match = (prog->IsES ? a->interface_type == b->interface_type : glsl_type_compare_no_precision(a->interface_type, b->interface_type)); /* Types must match. */ if (!interface_type_match) { /* Exception: if both the interface blocks are implicitly declared, * don't force their types to match. They might mismatch due to the two * shaders using different GLSL versions, and that's ok. */ if ((a->data.how_declared != nir_var_declared_implicitly || b->data.how_declared != nir_var_declared_implicitly) && (!prog->IsES || interstage_member_mismatch(prog, a->interface_type, b->interface_type))) return false; } /* Presence/absence of interface names must match. */ if (is_interface_instance(a) != is_interface_instance(b)) return false; /* For uniforms, instance names need not match. For shader ins/outs, * it's not clear from the spec whether they need to match, but * Mesa's implementation relies on them matching. */ if (is_interface_instance(a) && b->data.mode != nir_var_mem_ubo && b->data.mode != nir_var_mem_ssbo && strcmp(a->name, b->name) != 0) { return false; } bool type_match = (match_precision ? a->type == b->type : glsl_type_compare_no_precision(a->type, b->type)); /* If a block is an array then it must match across the shader. * Unsized arrays are also processed and matched agaist sized arrays. */ if (!type_match && (glsl_type_is_array(b->type) || glsl_type_is_array(a->type)) && (is_interface_instance(b) || is_interface_instance(a)) && !gl_nir_validate_intrastage_arrays(prog, b, a, a_stage, match_precision)) return false; return true; } /** * Check if two interfaces match, according to interstage (in/out) interface * matching rules. * * If \c extra_array_level is true, the consumer interface is required to be * an array and the producer interface is required to be a non-array. * This is used for tessellation control and geometry shader consumers. */ static bool interstage_match(struct gl_shader_program *prog, nir_variable *producer, nir_variable *consumer, bool extra_array_level) { /* Types must match. */ if (consumer->interface_type != producer->interface_type) { /* Exception: if both the interface blocks are implicitly declared, * don't force their types to match. They might mismatch due to the two * shaders using different GLSL versions, and that's ok. * * Also we store some member information such as interpolation in * glsl_type that doesn't always have to match across shader stages. * Therefore we make a pass over the members glsl_struct_field to make * sure we don't reject shaders where fields don't need to match. */ if ((consumer->data.how_declared != nir_var_declared_implicitly || producer->data.how_declared != nir_var_declared_implicitly) && interstage_member_mismatch(prog, consumer->interface_type, producer->interface_type)) return false; } /* Ignore outermost array if geom shader */ const glsl_type *consumer_instance_type; if (extra_array_level) { consumer_instance_type = glsl_get_array_element(consumer->type); } else { consumer_instance_type = consumer->type; } /* If a block is an array then it must match across shaders. * Since unsized arrays have been ruled out, we can check this by just * making sure the types are equal. */ if ((is_interface_instance(consumer) && glsl_type_is_array(consumer_instance_type)) || (is_interface_instance(producer) && glsl_type_is_array(producer->type))) { if (consumer_instance_type != producer->type) return false; } return true; } struct ifc_var { unsigned stage; nir_variable *var; }; /** * Lookup the interface definition. Return NULL if none is found. */ static struct ifc_var * ifc_lookup(struct hash_table *ht, nir_variable *var) { if (var->data.explicit_location && var->data.location >= VARYING_SLOT_VAR0) { char location_str[11]; snprintf(location_str, 11, "%d", var->data.location); const struct hash_entry *entry = _mesa_hash_table_search(ht, location_str); return entry ? (struct ifc_var *) entry->data : NULL; } else { const struct hash_entry *entry = _mesa_hash_table_search(ht, glsl_get_type_name(glsl_without_array(var->interface_type))); return entry ? (struct ifc_var *) entry->data : NULL; } } /** * Add a new interface definition. */ static void ifc_store(void *mem_ctx, struct hash_table *ht, nir_variable *var, unsigned stage) { struct ifc_var *ifc_var = ralloc(mem_ctx, struct ifc_var); ifc_var->var = var; ifc_var->stage = stage; if (var->data.explicit_location && var->data.location >= VARYING_SLOT_VAR0) { /* If explicit location is given then lookup the variable by location. * We turn the location into a string and use this as the hash key * rather than the name. Note: We allocate enough space for a 32-bit * unsigned location value which is overkill but future proof. */ char location_str[11]; snprintf(location_str, 11, "%d", var->data.location); _mesa_hash_table_insert(ht, ralloc_strdup(mem_ctx, location_str), ifc_var); } else { _mesa_hash_table_insert(ht, glsl_get_type_name(glsl_without_array(var->interface_type)), ifc_var); } } static const glsl_type * get_interface(const struct gl_linked_shader *shader, char *name, nir_variable_mode mode) { nir_foreach_variable_with_modes(var, shader->Program->nir, mode) { if (var->type == var->interface_type) { const char *ifc_name = glsl_get_type_name(var->interface_type); if (strcmp(name, ifc_name) == 0) return var->interface_type; } } return NULL; } static bool is_builtin_gl_in_block(nir_variable *var, int consumer_stage) { return !strcmp(var->name, "gl_in") && (consumer_stage == MESA_SHADER_TESS_CTRL || consumer_stage == MESA_SHADER_TESS_EVAL || consumer_stage == MESA_SHADER_GEOMETRY); } void gl_nir_validate_interstage_inout_blocks(struct gl_shader_program *prog, const struct gl_linked_shader *producer, const struct gl_linked_shader *consumer) { void *mem_ctx = ralloc_context(NULL); struct hash_table *ht = _mesa_hash_table_create(mem_ctx, _mesa_hash_string, _mesa_key_string_equal); /* VS -> GS, VS -> TCS, VS -> TES, TES -> GS */ const bool extra_array_level = (producer->Stage == MESA_SHADER_VERTEX && consumer->Stage != MESA_SHADER_FRAGMENT) || consumer->Stage == MESA_SHADER_GEOMETRY; /* Check that block re-declarations of gl_PerVertex are compatible * across shaders: From OpenGL Shading Language 4.5, section * "7.1 Built-In Language Variables", page 130 of the PDF: * * "If multiple shaders using members of a built-in block belonging * to the same interface are linked together in the same program, * they must all redeclare the built-in block in the same way, as * described in section 4.3.9 “Interface Blocks” for interface-block * matching, or a link-time error will result." * * This is done explicitly outside of iterating the member variable * declarations because it is possible that the variables are not used and * so they would have been optimised out. */ const glsl_type *consumer_iface = get_interface(consumer, "gl_PerVertex", nir_var_shader_in); const glsl_type *producer_iface = get_interface(producer, "gl_PerVertex", nir_var_shader_out); if (producer_iface && consumer_iface && interstage_member_mismatch(prog, consumer_iface, producer_iface)) { linker_error(prog, "Incompatible or missing gl_PerVertex re-declaration " "in consecutive shaders"); ralloc_free(mem_ctx); return; } /* Desktop OpenGL requires redeclaration of the built-in interfaces for * SSO programs. Passes above implement following rules: * * From Section 7.4 (Program Pipeline Objects) of the OpenGL 4.6 Core * spec: * * "To use any built-in input or output in the gl_PerVertex and * gl_PerFragment blocks in separable program objects, shader code * must redeclare those blocks prior to use. A separable program * will fail to link if: * * it contains multiple shaders of a single type with different * redeclarations of these built-in input and output blocks; or * * any shader uses a built-in block member not found in the * redeclaration of that block." * * ARB_separate_shader_objects issues section (issue #28) states that * redeclaration is not required for GLSL shaders using #version 140 or * earlier (since interface blocks are not possible with older versions). * * From Section 7.4.1 (Shader Interface Matching) of the OpenGL ES 3.1 * spec: * * "Built-in inputs or outputs do not affect interface matching." * * GL_OES_shader_io_blocks adds following: * * "When using any built-in input or output in the gl_PerVertex block * in separable program objects, shader code may redeclare that block * prior to use. If the shader does not redeclare the block, the * intrinsically declared definition of that block will be used." */ /* Add output interfaces from the producer to the symbol table. */ nir_foreach_shader_out_variable(var, producer->Program->nir) { if (!var->interface_type) continue; /* Built-in interface redeclaration check. */ if (prog->SeparateShader && !prog->IsES && prog->GLSL_Version >= 150 && var->data.how_declared == nir_var_declared_implicitly && var->data.used && !producer_iface) { linker_error(prog, "missing output builtin block %s redeclaration " "in separable shader program", glsl_get_type_name(var->interface_type)); ralloc_free(mem_ctx); return; } ifc_store(mem_ctx, ht, var, producer->Program->nir->info.stage); } /* Verify that the consumer's input interfaces match. */ nir_foreach_shader_in_variable(var, consumer->Program->nir) { if (!var->interface_type) continue; struct ifc_var *ifc_var = ifc_lookup(ht, var); nir_variable *producer_def = ifc_var ? ifc_var->var : NULL; /* Built-in interface redeclaration check. */ if (prog->SeparateShader && !prog->IsES && prog->GLSL_Version >= 150 && var->data.how_declared == nir_var_declared_implicitly && var->data.used && !producer_iface) { linker_error(prog, "missing input builtin block %s redeclaration " "in separable shader program", glsl_get_type_name(var->interface_type)); ralloc_free(mem_ctx); return; } /* The producer doesn't generate this input: fail to link. Skip built-in * 'gl_in[]' since that may not be present if the producer does not * write to any of the pre-defined outputs (e.g. if the vertex shader * does not write to gl_Position, etc), which is allowed and results in * undefined behavior. * * From Section 4.3.4 (Inputs) of the GLSL 1.50 spec: * * "Only the input variables that are actually read need to be written * by the previous stage; it is allowed to have superfluous * declarations of input variables." */ if (producer_def == NULL && !is_builtin_gl_in_block(var, consumer->Stage) && var->data.used) { linker_error(prog, "Input block `%s' is not an output of " "the previous stage\n", glsl_get_type_name(var->interface_type)); ralloc_free(mem_ctx); return; } if (producer_def && !interstage_match(prog, producer_def, var, extra_array_level)) { linker_error(prog, "definitions of interface block `%s' do not " "match\n", glsl_get_type_name(var->interface_type)); ralloc_free(mem_ctx); return; } } ralloc_free(mem_ctx); } void gl_nir_validate_interstage_uniform_blocks(struct gl_shader_program *prog, struct gl_linked_shader **stages) { void *mem_ctx = ralloc_context(NULL); /* Hash table mapping interface block name to a nir_variable */ struct hash_table *ht = _mesa_hash_table_create(mem_ctx, _mesa_hash_string, _mesa_key_string_equal); for (int i = 0; i < MESA_SHADER_STAGES; i++) { if (stages[i] == NULL) continue; const struct gl_linked_shader *stage = stages[i]; nir_foreach_variable_in_shader(var, stage->Program->nir) { if (!var->interface_type || (var->data.mode != nir_var_mem_ubo && var->data.mode != nir_var_mem_ssbo)) continue; struct ifc_var *ifc_var = ifc_lookup(ht, var); if (ifc_var == NULL) { ifc_store(mem_ctx, ht, var, i); } else { /* Interstage uniform matching rules are the same as intrastage * uniform matchin rules (for uniforms, it is as though all * shaders are in the same shader stage). */ nir_variable *old_def = ifc_var->var; if (!intrastage_match(old_def, var, prog, ifc_var->stage, false)) { linker_error(prog, "definitions of uniform block `%s' do not " "match\n", glsl_get_type_name(var->interface_type)); ralloc_free(mem_ctx); return; } } } } ralloc_free(mem_ctx); }