| 0,0 → 1,158 |
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| /* |
| * Copyright © 2012 Vincent Lejeune |
| * Copyright © 2012 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. |
| */ |
| |
| #include "ir.h" |
| #include "program/hash_table.h" |
| |
| /** |
| * \file lower_output_reads.cpp |
| * |
| * In GLSL, shader output variables (such as varyings) can be both read and |
| * written. However, on some hardware, reading an output register causes |
| * trouble. |
| * |
| * This pass creates temporary shadow copies of every (used) shader output, |
| * and replaces all accesses to use those instead. It also adds code to the |
| * main() function to copy the final values to the actual shader outputs. |
| */ |
| |
| class output_read_remover : public ir_hierarchical_visitor { |
| protected: |
| /** |
| * A hash table mapping from the original ir_variable shader outputs |
| * (ir_var_shader_out mode) to the new temporaries to be used instead. |
| */ |
| hash_table *replacements; |
| |
| void *mem_ctx; |
| public: |
| output_read_remover(); |
| ~output_read_remover(); |
| virtual ir_visitor_status visit(class ir_dereference_variable *); |
| virtual ir_visitor_status visit_leave(class ir_return *); |
| virtual ir_visitor_status visit_leave(class ir_function_signature *); |
| }; |
| |
| /** |
| * Hash function for the output variables - computes the hash of the name. |
| * NOTE: We're using the name string to ensure that the hash doesn't depend |
| * on any random factors, otherwise the output_read_remover could produce |
| * the random order of the assignments. |
| * |
| * NOTE: If you want to reuse this function please take into account that |
| * generally the names of the variables are non-unique. |
| */ |
| static unsigned |
| hash_table_var_hash(const void *key) |
| { |
| const ir_variable * var = static_cast<const ir_variable *>(key); |
| return hash_table_string_hash(var->name); |
| } |
| |
| output_read_remover::output_read_remover() |
| { |
| mem_ctx = ralloc_context(NULL); |
| replacements = |
| hash_table_ctor(0, hash_table_var_hash, hash_table_pointer_compare); |
| } |
| |
| output_read_remover::~output_read_remover() |
| { |
| hash_table_dtor(replacements); |
| ralloc_free(mem_ctx); |
| } |
| |
| ir_visitor_status |
| output_read_remover::visit(ir_dereference_variable *ir) |
| { |
| if (ir->var->mode != ir_var_shader_out) |
| return visit_continue; |
| |
| ir_variable *temp = (ir_variable *) hash_table_find(replacements, ir->var); |
| |
| /* If we don't have an existing temporary, create one. */ |
| if (temp == NULL) { |
| void *var_ctx = ralloc_parent(ir->var); |
| temp = new(var_ctx) ir_variable(ir->var->type, ir->var->name, |
| ir_var_temporary); |
| hash_table_insert(replacements, temp, ir->var); |
| ir->var->insert_after(temp); |
| } |
| |
| /* Update the dereference to use the temporary */ |
| ir->var = temp; |
| |
| return visit_continue; |
| } |
| |
| /** |
| * Create an assignment to copy a temporary value back to the actual output. |
| */ |
| static ir_assignment * |
| copy(void *ctx, ir_variable *output, ir_variable *temp) |
| { |
| ir_dereference_variable *lhs = new(ctx) ir_dereference_variable(output); |
| ir_dereference_variable *rhs = new(ctx) ir_dereference_variable(temp); |
| return new(ctx) ir_assignment(lhs, rhs); |
| } |
| |
| /** Insert a copy-back assignment before a "return" statement */ |
| static void |
| emit_return_copy(const void *key, void *data, void *closure) |
| { |
| ir_return *ir = (ir_return *) closure; |
| ir->insert_before(copy(ir, (ir_variable *) key, (ir_variable *) data)); |
| } |
| |
| /** Insert a copy-back assignment at the end of the main() function */ |
| static void |
| emit_main_copy(const void *key, void *data, void *closure) |
| { |
| ir_function_signature *sig = (ir_function_signature *) closure; |
| sig->body.push_tail(copy(sig, (ir_variable *) key, (ir_variable *) data)); |
| } |
| |
| ir_visitor_status |
| output_read_remover::visit_leave(ir_return *ir) |
| { |
| hash_table_call_foreach(replacements, emit_return_copy, ir); |
| return visit_continue; |
| } |
| |
| ir_visitor_status |
| output_read_remover::visit_leave(ir_function_signature *sig) |
| { |
| if (strcmp(sig->function_name(), "main") != 0) |
| return visit_continue; |
| |
| hash_table_call_foreach(replacements, emit_main_copy, sig); |
| return visit_continue; |
| } |
| |
| void |
| lower_output_reads(exec_list *instructions) |
| { |
| output_read_remover v; |
| visit_list_elements(&v, instructions); |
| } |