diff options
Diffstat (limited to 'src/compiler/glsl/opt_dead_builtin_variables.cpp')
| -rw-r--r-- | src/compiler/glsl/opt_dead_builtin_variables.cpp | 103 |
1 files changed, 103 insertions, 0 deletions
diff --git a/src/compiler/glsl/opt_dead_builtin_variables.cpp b/src/compiler/glsl/opt_dead_builtin_variables.cpp new file mode 100644 index 00000000000..03e578982b9 --- /dev/null +++ b/src/compiler/glsl/opt_dead_builtin_variables.cpp @@ -0,0 +1,103 @@ +/* + * 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 + * 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 "ir_visitor.h" +#include "ir_optimization.h" + +/** + * Pre-linking, optimize unused built-in variables + * + * Uniforms, constants, system values, inputs (vertex shader only), and + * outputs (fragment shader only) that are not used can be removed. + */ +void +optimize_dead_builtin_variables(exec_list *instructions, + enum ir_variable_mode other) +{ + foreach_in_list_safe(ir_variable, var, instructions) { + if (var->ir_type != ir_type_variable || var->data.used) + continue; + + if (var->data.mode != ir_var_uniform + && var->data.mode != ir_var_auto + && var->data.mode != ir_var_system_value + && var->data.mode != other) + continue; + + /* So that linker rules can later be enforced, we cannot elimate + * variables that were redeclared in the shader code. + */ + if ((var->data.mode == other || var->data.mode == ir_var_system_value) + && var->data.how_declared != ir_var_declared_implicitly) + continue; + + if (!is_gl_identifier(var->name)) + continue; + + /* gl_ModelViewProjectionMatrix and gl_Vertex are special because they + * are used by ftransform. No other built-in variable is used by a + * built-in function. The forward declarations of these variables in + * the built-in function shader does not have the "state slot" + * information, so removing these variables from the user shader will + * cause problems later. + * + * For compute shaders, gl_GlobalInvocationID has some dependencies, so + * we avoid removing these dependencies. + * + * We also avoid removing gl_GlobalInvocationID at this stage because it + * might be used by a linked shader. In this case it still needs to be + * initialized by the main function. + * + * gl_GlobalInvocationID = + * gl_WorkGroupID * gl_WorkGroupSize + gl_LocalInvocationID + * + * Similarly, we initialize gl_LocalInvocationIndex in the main function: + * + * gl_LocalInvocationIndex = + * gl_LocalInvocationID.z * gl_WorkGroupSize.x * gl_WorkGroupSize.y + + * gl_LocalInvocationID.y * gl_WorkGroupSize.x + + * gl_LocalInvocationID.x; + * + * Matrix uniforms with "Transpose" are not eliminated because there's + * an optimization pass that can turn references to the regular matrix + * into references to the transpose matrix. Eliminating the transpose + * matrix would cause that pass to generate references to undeclareds + * variables (thank you, ir_validate). + * + * It doesn't seem worth the effort to track when the transpose could be + * eliminated (i.e., when the non-transpose was eliminated). + */ + if (strcmp(var->name, "gl_ModelViewProjectionMatrix") == 0 + || strcmp(var->name, "gl_Vertex") == 0 + || strcmp(var->name, "gl_WorkGroupID") == 0 + || strcmp(var->name, "gl_WorkGroupSize") == 0 + || strcmp(var->name, "gl_LocalInvocationID") == 0 + || strcmp(var->name, "gl_GlobalInvocationID") == 0 + || strcmp(var->name, "gl_LocalInvocationIndex") == 0 + || strstr(var->name, "Transpose") != NULL) + continue; + + var->remove(); + } +} |