/* * Copyright © 2011 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 * 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. */ /** * \file lower_distance.cpp * * This pass accounts for the difference between the way * gl_ClipDistance is declared in standard GLSL (as an array of * floats), and the way it is frequently implemented in hardware (as * a pair of vec4s, with four clip distances packed into each). * * The declaration of gl_ClipDistance is replaced with a declaration * of gl_ClipDistanceMESA, and any references to gl_ClipDistance are * translated to refer to gl_ClipDistanceMESA with the appropriate * swizzling of array indices. For instance: * * gl_ClipDistance[i] * * is translated into: * * gl_ClipDistanceMESA[i>>2][i&3] * * Since some hardware may not internally represent gl_ClipDistance as a pair * of vec4's, this lowering pass is optional. To enable it, set the * LowerCombinedClipCullDistance flag in gl_shader_compiler_options to true. */ #include "main/macros.h" #include "glsl_symbol_table.h" #include "ir_rvalue_visitor.h" #include "ir.h" #include "program/prog_instruction.h" /* For WRITEMASK_* */ #define GLSL_CLIP_VAR_NAME "gl_ClipDistanceMESA" namespace { class lower_distance_visitor : public ir_rvalue_visitor { public: explicit lower_distance_visitor(gl_shader_stage shader_stage, const char *in_name, int total_size, int offset) : progress(false), old_distance_out_var(NULL), old_distance_in_var(NULL), new_distance_out_var(NULL), new_distance_in_var(NULL), shader_stage(shader_stage), in_name(in_name), total_size(total_size), offset(offset) { } explicit lower_distance_visitor(gl_shader_stage shader_stage, const char *in_name, const lower_distance_visitor *orig, int offset) : progress(false), old_distance_out_var(NULL), old_distance_in_var(NULL), new_distance_out_var(orig->new_distance_out_var), new_distance_in_var(orig->new_distance_in_var), shader_stage(shader_stage), in_name(in_name), total_size(orig->total_size), offset(offset) { } virtual ir_visitor_status visit(ir_variable *); void create_indices(ir_rvalue*, ir_rvalue *&, ir_rvalue *&); bool is_distance_vec8(ir_rvalue *ir); ir_rvalue *lower_distance_vec8(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_ClipDistance, if found. * * Note: * * - the in_var is for geometry and both tessellation shader inputs only. * * - since gl_ClipDistance is available in tessellation control, * tessellation evaluation and geometry shaders as both an input * and an output, it's possible for both old_distance_out_var * and old_distance_in_var to be non-null. */ ir_variable *old_distance_out_var; ir_variable *old_distance_in_var; /** * Pointer to the newly-created gl_ClipDistanceMESA variable. */ ir_variable *new_distance_out_var; ir_variable *new_distance_in_var; /** * Type of shader we are compiling (e.g. MESA_SHADER_VERTEX) */ const gl_shader_stage shader_stage; const char *in_name; int total_size; int offset; }; } /* anonymous namespace */ /** * Replace any declaration of 'in_name' as an array of floats with a * declaration of gl_ClipDistanceMESA as an array of vec4's. */ ir_visitor_status lower_distance_visitor::visit(ir_variable *ir) { ir_variable **old_var; ir_variable **new_var; if (!ir->name || strcmp(ir->name, in_name) != 0) return visit_continue; assert (ir->type->is_array()); if (ir->data.mode == ir_var_shader_out) { if (this->old_distance_out_var) return visit_continue; old_var = &old_distance_out_var; new_var = &new_distance_out_var; } else if (ir->data.mode == ir_var_shader_in) { if (this->old_distance_in_var) return visit_continue; old_var = &old_distance_in_var; new_var = &new_distance_in_var; } else { unreachable("not reached"); } this->progress = true; *old_var = ir; if (!(*new_var)) { unsigned new_size = (total_size + 3) / 4; /* Clone the old var so that we inherit all of its properties */ *new_var = ir->clone(ralloc_parent(ir), NULL); (*new_var)->name = ralloc_strdup(*new_var, GLSL_CLIP_VAR_NAME); (*new_var)->data.location = VARYING_SLOT_CLIP_DIST0; if (!ir->type->fields.array->is_array()) { /* gl_ClipDistance (used for vertex, tessellation evaluation and * geometry output, and fragment input). */ assert((ir->data.mode == ir_var_shader_in && this->shader_stage == MESA_SHADER_FRAGMENT) || (ir->data.mode == ir_var_shader_out && (this->shader_stage == MESA_SHADER_VERTEX || this->shader_stage == MESA_SHADER_TESS_EVAL || this->shader_stage == MESA_SHADER_GEOMETRY))); assert (ir->type->fields.array == glsl_type::float_type); (*new_var)->data.max_array_access = new_size - 1; /* And change the properties that we need to change */ (*new_var)->type = glsl_type::get_array_instance(glsl_type::vec4_type, new_size); } else { /* 2D gl_ClipDistance (used for tessellation control, tessellation * evaluation and geometry input, and tessellation control output). */ assert((ir->data.mode == ir_var_shader_in && (this->shader_stage == MESA_SHADER_GEOMETRY || this->shader_stage == MESA_SHADER_TESS_EVAL)) || this->shader_stage == MESA_SHADER_TESS_CTRL); assert (ir->type->fields.array->fields.array == glsl_type::float_type); /* And change the properties that we need to change */ (*new_var)->type = glsl_type::get_array_instance( glsl_type::get_array_instance(glsl_type::vec4_type, new_size), ir->type->array_size()); } ir->replace_with(*new_var); } else { ir->remove(); } return visit_continue; } /** * Create the necessary GLSL rvalues to index into gl_ClipDistanceMESA based * on the rvalue previously used to index into gl_ClipDistance. * * \param array_index Selects one of the vec4's in gl_ClipDistanceMESA * \param swizzle_index Selects a component within the vec4 selected by * array_index. */ void lower_distance_visitor::create_indices(ir_rvalue *old_index, ir_rvalue *&array_index, ir_rvalue *&swizzle_index) { void *ctx = ralloc_parent(old_index); /* Make sure old_index is a signed int so that the bitwise "shift" and * "and" operations below type check properly. */ if (old_index->type != glsl_type::int_type) { assert (old_index->type == glsl_type::uint_type); old_index = new(ctx) ir_expression(ir_unop_u2i, old_index); } ir_constant *old_index_constant = old_index->constant_expression_value(); if (old_index_constant) { /* gl_ClipDistance is being accessed via a constant index. Don't bother * creating expressions to calculate the lowered indices. Just create * constants. */ int const_val = old_index_constant->get_int_component(0) + offset; array_index = new(ctx) ir_constant(const_val / 4); swizzle_index = new(ctx) ir_constant(const_val % 4); } else { /* Create a variable to hold the value of old_index (so that we * don't compute it twice). */ ir_variable *old_index_var = new(ctx) ir_variable( glsl_type::int_type, "distance_index", ir_var_temporary); this->base_ir->insert_before(old_index_var); this->base_ir->insert_before(new(ctx) ir_assignment( new(ctx) ir_dereference_variable(old_index_var), old_index)); /* Create the expression distance_index / 4. Do this as a bit * shift because that's likely to be more efficient. */ array_index = new(ctx) ir_expression( ir_binop_rshift, new(ctx) ir_expression(ir_binop_add, new(ctx) ir_dereference_variable(old_index_var), new(ctx) ir_constant(offset)), new(ctx) ir_constant(2)); /* Create the expression distance_index % 4. Do this as a bitwise * AND because that's likely to be more efficient. */ swizzle_index = new(ctx) ir_expression( ir_binop_bit_and, new(ctx) ir_expression(ir_binop_add, new(ctx) ir_dereference_variable(old_index_var), new(ctx) ir_constant(offset)), new(ctx) ir_constant(3)); } } /** * Determine whether the given rvalue describes an array of 8 floats that * needs to be lowered to an array of 2 vec4's; that is, determine whether it * matches one of the following patterns: * * - gl_ClipDistance (if gl_ClipDistance is 1D) * - gl_ClipDistance[i] (if gl_ClipDistance is 2D) */ bool lower_distance_visitor::is_distance_vec8(ir_rvalue *ir) { /* Note that geometry shaders contain gl_ClipDistance both as an input * (which is a 2D array) and an output (which is a 1D array), so it's * possible for both this->old_distance_out_var and * this->old_distance_in_var to be non-NULL in the same shader. */ if (!ir->type->is_array()) return false; if (ir->type->fields.array != glsl_type::float_type) return false; if (this->old_distance_out_var) { if (ir->variable_referenced() == this->old_distance_out_var) return true; } if (this->old_distance_in_var) { assert(this->shader_stage == MESA_SHADER_TESS_CTRL || this->shader_stage == MESA_SHADER_TESS_EVAL || this->shader_stage == MESA_SHADER_GEOMETRY || this->shader_stage == MESA_SHADER_FRAGMENT); if (ir->variable_referenced() == this->old_distance_in_var) return true; } return false; } /** * If the given ir satisfies is_distance_vec8(), return new ir * representing its lowered equivalent. That is, map: * * - gl_ClipDistance => gl_ClipDistanceMESA (if gl_ClipDistance is 1D) * - gl_ClipDistance[i] => gl_ClipDistanceMESA[i] (if gl_ClipDistance is 2D) * * Otherwise return NULL. */ ir_rvalue * lower_distance_visitor::lower_distance_vec8(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_distance_out_var) { if (ir->variable_referenced() == this->old_distance_out_var) new_var = &this->new_distance_out_var; } if (this->old_distance_in_var) { if (ir->variable_referenced() == this->old_distance_in_var) new_var = &this->new_distance_in_var; } if (new_var == NULL) return NULL; if (ir->as_dereference_variable()) { return new(ralloc_parent(ir)) ir_dereference_variable(*new_var); } else { ir_dereference_array *array_ref = ir->as_dereference_array(); assert(array_ref); assert(array_ref->array->as_dereference_variable()); return new(ralloc_parent(ir)) ir_dereference_array(*new_var, array_ref->array_index); } } void lower_distance_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_ClipDistance * with an expression that indexes into one of the vec4's in * gl_ClipDistanceMESA and accesses the appropriate component. */ ir_rvalue *lowered_vec8 = this->lower_distance_vec8(array_deref->array); if (lowered_vec8 != NULL) { this->progress = true; ir_rvalue *array_index; ir_rvalue *swizzle_index; this->create_indices(array_deref->array_index, array_index, swizzle_index); void *mem_ctx = ralloc_parent(array_deref); ir_dereference_array *const new_array_deref = new(mem_ctx) ir_dereference_array(lowered_vec8, array_index); ir_expression *const expr = new(mem_ctx) ir_expression(ir_binop_vector_extract, new_array_deref, swizzle_index); *rv = expr; } } void lower_distance_visitor::fix_lhs(ir_assignment *ir) { if (ir->lhs->ir_type == ir_type_expression) { void *mem_ctx = ralloc_parent(ir); ir_expression *const expr = (ir_expression *) ir->lhs; /* The expression must be of the form: * * (vector_extract gl_ClipDistanceMESA[i], j). */ assert(expr->operation == ir_binop_vector_extract); assert(expr->operands[0]->ir_type == ir_type_dereference_array); assert(expr->operands[0]->type == glsl_type::vec4_type); ir_dereference *const new_lhs = (ir_dereference *) expr->operands[0]; ir->rhs = new(mem_ctx) ir_expression(ir_triop_vector_insert, glsl_type::vec4_type, new_lhs->clone(mem_ctx, NULL), ir->rhs, expr->operands[1]); ir->set_lhs(new_lhs); ir->write_mask = WRITEMASK_XYZW; } } /** * Replace any assignment having the 1D gl_ClipDistance (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_ClipDistanceMESA as appropriate. * * We need to do a similar replacement for 2D gl_ClipDistance, however since * it's an input, the only case we need to address is where a 1D slice of it * is the entire RHS of an assignment, e.g.: * * foo = gl_in[i].gl_ClipDistance */ ir_visitor_status lower_distance_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_distance_vec8(ir->lhs) || this->is_distance_vec8(ir->rhs)) { /* LHS or RHS of the assignment is the entire 1D gl_ClipDistance array * (or a 1D slice of a 2D gl_ClipDistance input array). Since we are * reshaping gl_ClipDistance from an array of floats to an array of * vec4's, 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_distance_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 1D gl_ClipDistance 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_ClipDistance. Each of these * assignments is then lowered to refer to gl_ClipDistanceMESA. * * We need to do a similar replacement for 2D gl_ClipDistance, however since * it's an input, the only case we need to address is where a 1D slice of it * is passed as an "in" parameter to an ir_call, e.g.: * * foo(gl_in[i].gl_ClipDistance) */ ir_visitor_status lower_distance_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_distance_vec8(actual_param)) { /* User is trying to pass the whole 1D gl_ClipDistance array (or a 1D * slice of a 2D gl_ClipDistance array) to a function call. Since we * are reshaping gl_ClipDistance from an array of floats to an array * of vec4's, this isn't going to work anymore, so use a temporary * array instead. */ ir_variable *temp_clip_distance = new(ctx) ir_variable( actual_param->type, "temp_clip_distance", ir_var_temporary); this->base_ir->insert_before(temp_clip_distance); actual_param->replace_with( new(ctx) ir_dereference_variable(temp_clip_distance)); if (formal_param->data.mode == ir_var_function_in || formal_param->data.mode == ir_var_function_inout) { /* Copy from gl_ClipDistance 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_clip_distance), 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_ClipDistance 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_clip_distance)); this->base_ir->insert_after(new_assignment); this->visit_new_assignment(new_assignment); } } } return rvalue_visit(ir); } namespace { class lower_distance_visitor_counter : public ir_rvalue_visitor { public: explicit lower_distance_visitor_counter(void) : in_clip_size(0), in_cull_size(0), out_clip_size(0), out_cull_size(0) { } virtual ir_visitor_status visit(ir_variable *); virtual void handle_rvalue(ir_rvalue **rvalue); int in_clip_size; int in_cull_size; int out_clip_size; int out_cull_size; }; } /** * Count gl_ClipDistance and gl_CullDistance sizes. */ ir_visitor_status lower_distance_visitor_counter::visit(ir_variable *ir) { int *clip_size, *cull_size; if (!ir->name) return visit_continue; if (ir->data.mode == ir_var_shader_out) { clip_size = &out_clip_size; cull_size = &out_cull_size; } else if (ir->data.mode == ir_var_shader_in) { clip_size = &in_clip_size; cull_size = &in_cull_size; } else return visit_continue; if (ir->type->is_unsized_array()) return visit_continue; if (*clip_size == 0) { if (!strcmp(ir->name, "gl_ClipDistance")) { if (!ir->type->fields.array->is_array()) *clip_size = ir->type->array_size(); else *clip_size = ir->type->fields.array->array_size(); } } if (*cull_size == 0) { if (!strcmp(ir->name, "gl_CullDistance")) { if (!ir->type->fields.array->is_array()) *cull_size = ir->type->array_size(); else *cull_size = ir->type->fields.array->array_size(); } } return visit_continue; } void lower_distance_visitor_counter::handle_rvalue(ir_rvalue **rv) { return; } bool lower_clip_cull_distance(struct gl_shader_program *prog, struct gl_linked_shader *shader) { int clip_size, cull_size; lower_distance_visitor_counter count; visit_list_elements(&count, shader->ir); clip_size = MAX2(count.in_clip_size, count.out_clip_size); cull_size = MAX2(count.in_cull_size, count.out_cull_size); if (clip_size == 0 && cull_size == 0) return false; lower_distance_visitor v(shader->Stage, "gl_ClipDistance", clip_size + cull_size, 0); visit_list_elements(&v, shader->ir); lower_distance_visitor v2(shader->Stage, "gl_CullDistance", &v, clip_size); visit_list_elements(&v2, shader->ir); if (v2.new_distance_out_var) shader->symbols->add_variable(v2.new_distance_out_var); if (v2.new_distance_in_var) shader->symbols->add_variable(v2.new_distance_in_var); return v2.progress; }