diff options
| -rw-r--r-- | src/glsl/linker.cpp | 108 |
1 files changed, 58 insertions, 50 deletions
diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp index 61405ea71b8..3adcddd16b6 100644 --- a/src/glsl/linker.cpp +++ b/src/glsl/linker.cpp @@ -1836,9 +1836,9 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog) goto done; } - unsigned prev; - for (prev = 0; prev < MESA_SHADER_TYPES; prev++) { - if (prog->_LinkedShaders[prev] != NULL) + unsigned first; + for (first = 0; first < MESA_SHADER_TYPES; first++) { + if (prog->_LinkedShaders[first] != NULL) break; } @@ -1850,7 +1850,7 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog) * non-zero, but the program object has no vertex or geometry * shader; */ - if (prev >= MESA_SHADER_FRAGMENT) { + if (first >= MESA_SHADER_FRAGMENT) { linker_error(prog, "Transform feedback varyings specified, but " "no vertex or geometry shader is present."); goto done; @@ -1864,69 +1864,77 @@ link_shaders(struct gl_context *ctx, struct gl_shader_program *prog) goto done; } - for (unsigned i = prev + 1; i < MESA_SHADER_TYPES; i++) { - if (prog->_LinkedShaders[i] == NULL) - continue; - - if (!assign_varying_locations( - ctx, mem_ctx, prog, prog->_LinkedShaders[prev], prog->_LinkedShaders[i], - i == MESA_SHADER_FRAGMENT ? num_tfeedback_decls : 0, - tfeedback_decls)) - goto done; - - prev = i; + /* Linking the stages in the opposite order (from fragment to vertex) + * ensures that inter-shader outputs written to in an earlier stage are + * eliminated if they are (transitively) not used in a later stage. + */ + int last, next; + for (last = MESA_SHADER_TYPES-1; last >= 0; last--) { + if (prog->_LinkedShaders[last] != NULL) + break; } - if (prev != MESA_SHADER_FRAGMENT && num_tfeedback_decls != 0) { - /* There was no fragment shader, but we still have to assign varying - * locations for use by transform feedback. - */ - if (!assign_varying_locations( - ctx, mem_ctx, prog, prog->_LinkedShaders[prev], NULL, num_tfeedback_decls, - tfeedback_decls)) - goto done; - } + if (last >= 0 && last < MESA_SHADER_FRAGMENT) { + gl_shader *const sh = prog->_LinkedShaders[last]; - if (!store_tfeedback_info(ctx, prog, num_tfeedback_decls, tfeedback_decls)) - goto done; + if (num_tfeedback_decls != 0) { + /* There was no fragment shader, but we still have to assign varying + * locations for use by transform feedback. + */ + if (!assign_varying_locations(ctx, mem_ctx, prog, + sh, NULL, + num_tfeedback_decls, tfeedback_decls)) + goto done; + } - if (prog->_LinkedShaders[MESA_SHADER_VERTEX] != NULL) { - demote_shader_inputs_and_outputs(prog->_LinkedShaders[MESA_SHADER_VERTEX], - ir_var_shader_out); + demote_shader_inputs_and_outputs(sh, ir_var_shader_out); - /* Eliminate code that is now dead due to unused vertex outputs being - * demoted. + /* Eliminate code that is now dead due to unused outputs being demoted. */ - while (do_dead_code(prog->_LinkedShaders[MESA_SHADER_VERTEX]->ir, false)) - ; + while (do_dead_code(sh->ir, false)) + ; } - - if (prog->_LinkedShaders[MESA_SHADER_GEOMETRY] != NULL) { - gl_shader *const sh = prog->_LinkedShaders[MESA_SHADER_GEOMETRY]; + else if (first == MESA_SHADER_FRAGMENT) { + /* If the program only contains a fragment shader, just demote + * user-defined varyings. + */ + gl_shader *const sh = prog->_LinkedShaders[first]; demote_shader_inputs_and_outputs(sh, ir_var_shader_in); - demote_shader_inputs_and_outputs(sh, ir_var_shader_out); - /* Eliminate code that is now dead due to unused geometry outputs being - * demoted. - */ - while (do_dead_code(prog->_LinkedShaders[MESA_SHADER_GEOMETRY]->ir, false)) - ; + while (do_dead_code(sh->ir, false)) + ; } - if (prog->_LinkedShaders[MESA_SHADER_FRAGMENT] != NULL) { - gl_shader *const sh = prog->_LinkedShaders[MESA_SHADER_FRAGMENT]; + next = last; + for (int i = next - 1; i >= 0; i--) { + if (prog->_LinkedShaders[i] == NULL) + continue; - demote_shader_inputs_and_outputs(sh, ir_var_shader_in); + gl_shader *const sh_i = prog->_LinkedShaders[i]; + gl_shader *const sh_next = prog->_LinkedShaders[next]; - /* Eliminate code that is now dead due to unused fragment inputs being - * demoted. This shouldn't actually do anything other than remove - * declarations of the (now unused) global variables. + if (!assign_varying_locations(ctx, mem_ctx, prog, sh_i, sh_next, + next == MESA_SHADER_FRAGMENT ? num_tfeedback_decls : 0, + tfeedback_decls)) + goto done; + + demote_shader_inputs_and_outputs(sh_i, ir_var_shader_out); + demote_shader_inputs_and_outputs(sh_next, ir_var_shader_in); + + /* Eliminate code that is now dead due to unused outputs being demoted. */ - while (do_dead_code(prog->_LinkedShaders[MESA_SHADER_FRAGMENT]->ir, false)) - ; + while (do_dead_code(sh_i->ir, false)) + ; + while (do_dead_code(sh_next->ir, false)) + ; + + next = i; } + if (!store_tfeedback_info(ctx, prog, num_tfeedback_decls, tfeedback_decls)) + goto done; + update_array_sizes(prog); link_assign_uniform_locations(prog); store_fragdepth_layout(prog); |