| 0,0 → 1,142 |
|---|
| /* |
| * Copyright © 2010 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 opt_dead_code.cpp |
| * |
| * Eliminates dead assignments and variable declarations from the code. |
| */ |
| |
| #include "ir.h" |
| #include "ir_visitor.h" |
| #include "ir_variable_refcount.h" |
| #include "glsl_types.h" |
| |
| static bool debug = false; |
| |
| /** |
| * Do a dead code pass over instructions and everything that instructions |
| * references. |
| * |
| * Note that this will remove assignments to globals, so it is not suitable |
| * for usage on an unlinked instruction stream. |
| */ |
| bool |
| do_dead_code(exec_list *instructions) |
| { |
| ir_variable_refcount_visitor v; |
| bool progress = false; |
| |
| v.run(instructions); |
| |
| foreach_iter(exec_list_iterator, iter, v.variable_list) { |
| variable_entry *entry = (variable_entry *)iter.get(); |
| |
| /* Since each assignment is a reference, the refereneced count must be |
| * greater than or equal to the assignment count. If they are equal, |
| * then all of the references are assignments, and the variable is |
| * dead. |
| * |
| * Note that if the variable is neither assigned nor referenced, both |
| * counts will be zero and will be caught by the equality test. |
| */ |
| assert(entry->referenced_count >= entry->assigned_count); |
| |
| if (debug) { |
| printf("%s@%p: %d refs, %d assigns, %sdeclared in our scope\n", |
| entry->var->name, (void *) entry->var, |
| entry->referenced_count, entry->assigned_count, |
| entry->declaration ? "" : "not "); |
| } |
| |
| if ((entry->referenced_count > entry->assigned_count) |
| || !entry->declaration) |
| continue; |
| |
| if (entry->assign) { |
| /* Remove a single dead assignment to the variable we found. |
| * Don't do so if it's a shader output, though. |
| */ |
| if (entry->var->mode != ir_var_out && |
| entry->var->mode != ir_var_inout && |
| !ir_has_call(entry->assign)) { |
| entry->assign->remove(); |
| progress = true; |
| |
| if (debug) { |
| printf("Removed assignment to %s@%p\n", |
| entry->var->name, (void *) entry->var); |
| } |
| } |
| } else { |
| /* If there are no assignments or references to the variable left, |
| * then we can remove its declaration. |
| */ |
| |
| /* uniform initializers are precious, and could get used by another |
| * stage. |
| */ |
| if (entry->var->mode == ir_var_uniform && |
| entry->var->constant_value) |
| continue; |
| |
| entry->var->remove(); |
| progress = true; |
| |
| if (debug) { |
| printf("Removed declaration of %s@%p\n", |
| entry->var->name, (void *) entry->var); |
| } |
| } |
| } |
| |
| return progress; |
| } |
| |
| /** |
| * Does a dead code pass on the functions present in the instruction stream. |
| * |
| * This is suitable for use while the program is not linked, as it will |
| * ignore variable declarations (and the assignments to them) for variables |
| * with global scope. |
| */ |
| bool |
| do_dead_code_unlinked(exec_list *instructions) |
| { |
| bool progress = false; |
| |
| foreach_iter(exec_list_iterator, iter, *instructions) { |
| ir_instruction *ir = (ir_instruction *)iter.get(); |
| ir_function *f = ir->as_function(); |
| if (f) { |
| foreach_iter(exec_list_iterator, sigiter, *f) { |
| ir_function_signature *sig = |
| (ir_function_signature *) sigiter.get(); |
| if (do_dead_code(&sig->body)) |
| progress = true; |
| } |
| } |
| } |
| |
| return progress; |
| } |