/* * Copyright © 2014 Intel Corporation * * Permission is hereby granted, free of charge, to any person obtaining a * copy of this software and associated documentation files (the "Software"), * to deal in the Software without restriction, including without limitation * the rights to use, copy, modify, merge, publish, distribute, sublicense, * and/or sell copies of the Software, and to permit persons to whom the * * The above copyright notice and this permission notice (including the next * paragraph) shall be included in all copies or substantial portions of the * Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER * DEALINGS IN THE SOFTWARE. */ /** * \file lower_tess_level.cpp * * This pass accounts for the difference between the way gl_TessLevelOuter * and gl_TessLevelInner is declared in standard GLSL (as an array of * floats), and the way it is frequently implemented in hardware (as a vec4 * and vec2). * * The declaration of gl_TessLevel* is replaced with a declaration * of gl_TessLevel*MESA, and any references to gl_TessLevel* are * translated to refer to gl_TessLevel*MESA with the appropriate * swizzling of array indices. For instance: * * gl_TessLevelOuter[i] * * is translated into: * * gl_TessLevelOuterMESA[i] * * Since some hardware may not internally represent gl_TessLevel* as a pair * of vec4's, this lowering pass is optional. To enable it, set the * LowerTessLevel flag in gl_shader_compiler_options to true. */ #include "glsl_symbol_table.h" #include "ir_rvalue_visitor.h" #include "ir.h" #include "program/prog_instruction.h" /* For WRITEMASK_* */ namespace { class lower_tess_level_visitor : public ir_rvalue_visitor { public: explicit lower_tess_level_visitor(gl_shader_stage shader_stage) : progress(false), old_tess_level_outer_var(NULL), old_tess_level_inner_var(NULL), new_tess_level_outer_var(NULL), new_tess_level_inner_var(NULL), shader_stage(shader_stage) { } virtual ir_visitor_status visit(ir_variable *); bool is_tess_level_array(ir_rvalue *ir); ir_rvalue *lower_tess_level_array(ir_rvalue *ir); virtual ir_visitor_status visit_leave(ir_assignment *); void visit_new_assignment(ir_assignment *ir); virtual ir_visitor_status visit_leave(ir_call *); virtual void handle_rvalue(ir_rvalue **rvalue); void fix_lhs(ir_assignment *); bool progress; /** * Pointer to the declaration of gl_TessLevel*, if found. */ ir_variable *old_tess_level_outer_var; ir_variable *old_tess_level_inner_var; /** * Pointer to the newly-created gl_TessLevel*MESA variables. */ ir_variable *new_tess_level_outer_var; ir_variable *new_tess_level_inner_var; /** * Type of shader we are compiling (e.g. MESA_SHADER_TESS_CTRL) */ const gl_shader_stage shader_stage; }; } /* anonymous namespace */ /** * Replace any declaration of gl_TessLevel* as an array of floats with a * declaration of gl_TessLevel*MESA as a vec4. */ ir_visitor_status lower_tess_level_visitor::visit(ir_variable *ir) { if ((!ir->name) || ((strcmp(ir->name, "gl_TessLevelInner") != 0) && (strcmp(ir->name, "gl_TessLevelOuter") != 0))) return visit_continue; assert (ir->type->is_array()); if (strcmp(ir->name, "gl_TessLevelOuter") == 0) { if (this->old_tess_level_outer_var) return visit_continue; old_tess_level_outer_var = ir; assert(ir->type->fields.array == glsl_type::float_type); /* Clone the old var so that we inherit all of its properties */ new_tess_level_outer_var = ir->clone(ralloc_parent(ir), NULL); /* And change the properties that we need to change */ new_tess_level_outer_var->name = ralloc_strdup(new_tess_level_outer_var, "gl_TessLevelOuterMESA"); new_tess_level_outer_var->type = glsl_type::vec4_type; new_tess_level_outer_var->data.max_array_access = 0; ir->replace_with(new_tess_level_outer_var); } else if (strcmp(ir->name, "gl_TessLevelInner") == 0) { if (this->old_tess_level_inner_var) return visit_continue; old_tess_level_inner_var = ir; assert(ir->type->fields.array == glsl_type::float_type); /* Clone the old var so that we inherit all of its properties */ new_tess_level_inner_var = ir->clone(ralloc_parent(ir), NULL); /* And change the properties that we need to change */ new_tess_level_inner_var->name = ralloc_strdup(new_tess_level_inner_var, "gl_TessLevelInnerMESA"); new_tess_level_inner_var->type = glsl_type::vec2_type; new_tess_level_inner_var->data.max_array_access = 0; ir->replace_with(new_tess_level_inner_var); } else { assert(0); } this->progress = true; return visit_continue; } /** * Determine whether the given rvalue describes an array of floats that * needs to be lowered to a vec4; that is, determine whether it * matches one of the following patterns: * * - gl_TessLevelOuter * - gl_TessLevelInner */ bool lower_tess_level_visitor::is_tess_level_array(ir_rvalue *ir) { if (!ir->type->is_array()) return false; if (ir->type->fields.array != glsl_type::float_type) return false; if (this->old_tess_level_outer_var) { if (ir->variable_referenced() == this->old_tess_level_outer_var) return true; } if (this->old_tess_level_inner_var) { if (ir->variable_referenced() == this->old_tess_level_inner_var) return true; } return false; } /** * If the given ir satisfies is_tess_level_array(), return new ir * representing its lowered equivalent. That is, map: * * - gl_TessLevelOuter => gl_TessLevelOuterMESA * - gl_TessLevelInner => gl_TessLevelInnerMESA * * Otherwise return NULL. */ ir_rvalue * lower_tess_level_visitor::lower_tess_level_array(ir_rvalue *ir) { if (!ir->type->is_array()) return NULL; if (ir->type->fields.array != glsl_type::float_type) return NULL; ir_variable **new_var = NULL; if (this->old_tess_level_outer_var) { if (ir->variable_referenced() == this->old_tess_level_outer_var) new_var = &this->new_tess_level_outer_var; } if (this->old_tess_level_inner_var) { if (ir->variable_referenced() == this->old_tess_level_inner_var) new_var = &this->new_tess_level_inner_var; } if (new_var == NULL) return NULL; assert(ir->as_dereference_variable()); return new(ralloc_parent(ir)) ir_dereference_variable(*new_var); } void lower_tess_level_visitor::handle_rvalue(ir_rvalue **rv) { if (*rv == NULL) return; ir_dereference_array *const array_deref = (*rv)->as_dereference_array(); if (array_deref == NULL) return; /* Replace any expression that indexes one of the floats in gl_TessLevel* * with an expression that indexes into one of the vec4's * gl_TessLevel*MESA and accesses the appropriate component. */ ir_rvalue *lowered_vec4 = this->lower_tess_level_array(array_deref->array); if (lowered_vec4 != NULL) { this->progress = true; void *mem_ctx = ralloc_parent(array_deref); ir_expression *const expr = new(mem_ctx) ir_expression(ir_binop_vector_extract, lowered_vec4, array_deref->array_index); *rv = expr; } } void lower_tess_level_visitor::fix_lhs(ir_assignment *ir) { if (ir->lhs->ir_type != ir_type_expression) return; void *mem_ctx = ralloc_parent(ir); ir_expression *const expr = (ir_expression *) ir->lhs; /* The expression must be of the form: * * (vector_extract gl_TessLevel*MESA, j). */ assert(expr->operation == ir_binop_vector_extract); assert(expr->operands[0]->ir_type == ir_type_dereference_variable); assert((expr->operands[0]->type == glsl_type::vec4_type) || (expr->operands[0]->type == glsl_type::vec2_type)); ir_dereference *const new_lhs = (ir_dereference *) expr->operands[0]; ir_constant *old_index_constant = expr->operands[1]->constant_expression_value(mem_ctx); if (!old_index_constant) { ir->rhs = new(mem_ctx) ir_expression(ir_triop_vector_insert, expr->operands[0]->type, new_lhs->clone(mem_ctx, NULL), ir->rhs, expr->operands[1]); } ir->set_lhs(new_lhs); if (old_index_constant) { /* gl_TessLevel* is being accessed via a constant index. Don't bother * creating a vector insert op. Just use a write mask. */ ir->write_mask = 1 << old_index_constant->get_int_component(0); } else { ir->write_mask = (1 << expr->operands[0]->type->vector_elements) - 1; } } /** * Replace any assignment having a gl_TessLevel* (undereferenced) as * its LHS or RHS with a sequence of assignments, one for each component of * the array. Each of these assignments is lowered to refer to * gl_TessLevel*MESA as appropriate. */ ir_visitor_status lower_tess_level_visitor::visit_leave(ir_assignment *ir) { /* First invoke the base class visitor. This causes handle_rvalue() to be * called on ir->rhs and ir->condition. */ ir_rvalue_visitor::visit_leave(ir); if (this->is_tess_level_array(ir->lhs) || this->is_tess_level_array(ir->rhs)) { /* LHS or RHS of the assignment is the entire gl_TessLevel* array. * Since we are * reshaping gl_TessLevel* from an array of floats to a * vec4, this isn't going to work as a bulk assignment anymore, so * unroll it to element-by-element assignments and lower each of them. * * Note: to unroll into element-by-element assignments, we need to make * clones of the LHS and RHS. This is safe because expressions and * l-values are side-effect free. */ void *ctx = ralloc_parent(ir); int array_size = ir->lhs->type->array_size(); for (int i = 0; i < array_size; ++i) { ir_dereference_array *new_lhs = new(ctx) ir_dereference_array( ir->lhs->clone(ctx, NULL), new(ctx) ir_constant(i)); ir_dereference_array *new_rhs = new(ctx) ir_dereference_array( ir->rhs->clone(ctx, NULL), new(ctx) ir_constant(i)); this->handle_rvalue((ir_rvalue **) &new_rhs); /* Handle the LHS after creating the new assignment. This must * happen in this order because handle_rvalue may replace the old LHS * with an ir_expression of ir_binop_vector_extract. Since this is * not a valide l-value, this will cause an assertion in the * ir_assignment constructor to fail. * * If this occurs, replace the mangled LHS with a dereference of the * vector, and replace the RHS with an ir_triop_vector_insert. */ ir_assignment *const assign = new(ctx) ir_assignment(new_lhs, new_rhs); this->handle_rvalue((ir_rvalue **) &assign->lhs); this->fix_lhs(assign); this->base_ir->insert_before(assign); } ir->remove(); return visit_continue; } /* Handle the LHS as if it were an r-value. Normally * rvalue_visit(ir_assignment *) only visits the RHS, but we need to lower * expressions in the LHS as well. * * This may cause the LHS to get replaced with an ir_expression of * ir_binop_vector_extract. If this occurs, replace it with a dereference * of the vector, and replace the RHS with an ir_triop_vector_insert. */ handle_rvalue((ir_rvalue **)&ir->lhs); this->fix_lhs(ir); return rvalue_visit(ir); } /** * Set up base_ir properly and call visit_leave() on a newly created * ir_assignment node. This is used in cases where we have to insert an * ir_assignment in a place where we know the hierarchical visitor won't see * it. */ void lower_tess_level_visitor::visit_new_assignment(ir_assignment *ir) { ir_instruction *old_base_ir = this->base_ir; this->base_ir = ir; ir->accept(this); this->base_ir = old_base_ir; } /** * If a gl_TessLevel* variable appears as an argument in an ir_call * expression, replace it with a temporary variable, and make sure the ir_call * is preceded and/or followed by assignments that copy the contents of the * temporary variable to and/or from gl_TessLevel*. Each of these * assignments is then lowered to refer to gl_TessLevel*MESA. */ ir_visitor_status lower_tess_level_visitor::visit_leave(ir_call *ir) { void *ctx = ralloc_parent(ir); const exec_node *formal_param_node = ir->callee->parameters.get_head_raw(); const exec_node *actual_param_node = ir->actual_parameters.get_head_raw(); while (!actual_param_node->is_tail_sentinel()) { ir_variable *formal_param = (ir_variable *) formal_param_node; ir_rvalue *actual_param = (ir_rvalue *) actual_param_node; /* Advance formal_param_node and actual_param_node now so that we can * safely replace actual_param with another node, if necessary, below. */ formal_param_node = formal_param_node->next; actual_param_node = actual_param_node->next; if (!this->is_tess_level_array(actual_param)) continue; /* User is trying to pass a whole gl_TessLevel* array to a function * call. Since we are reshaping gl_TessLevel* from an array of floats * to a vec4, this isn't going to work anymore, so use a temporary * array instead. */ ir_variable *temp = new(ctx) ir_variable( actual_param->type, "temp_tess_level", ir_var_temporary); this->base_ir->insert_before(temp); actual_param->replace_with( new(ctx) ir_dereference_variable(temp)); if (formal_param->data.mode == ir_var_function_in || formal_param->data.mode == ir_var_function_inout) { /* Copy from gl_TessLevel* to the temporary before the call. * Since we are going to insert this copy before the current * instruction, we need to visit it afterwards to make sure it * gets lowered. */ ir_assignment *new_assignment = new(ctx) ir_assignment( new(ctx) ir_dereference_variable(temp), actual_param->clone(ctx, NULL)); this->base_ir->insert_before(new_assignment); this->visit_new_assignment(new_assignment); } if (formal_param->data.mode == ir_var_function_out || formal_param->data.mode == ir_var_function_inout) { /* Copy from the temporary to gl_TessLevel* after the call. * Since visit_list_elements() has already decided which * instruction it's going to visit next, we need to visit * afterwards to make sure it gets lowered. */ ir_assignment *new_assignment = new(ctx) ir_assignment( actual_param->clone(ctx, NULL), new(ctx) ir_dereference_variable(temp)); this->base_ir->insert_after(new_assignment); this->visit_new_assignment(new_assignment); } } return rvalue_visit(ir); } bool lower_tess_level(gl_linked_shader *shader) { if ((shader->Stage != MESA_SHADER_TESS_CTRL) && (shader->Stage != MESA_SHADER_TESS_EVAL)) return false; lower_tess_level_visitor v(shader->Stage); visit_list_elements(&v, shader->ir); if (v.new_tess_level_outer_var) shader->symbols->add_variable(v.new_tess_level_outer_var); if (v.new_tess_level_inner_var) shader->symbols->add_variable(v.new_tess_level_inner_var); return v.progress; }