From d030a3404ca0fedf365cb0fd41eaad7abc8ff132 Mon Sep 17 00:00:00 2001 From: Ian Romanick Date: Tue, 11 Feb 2014 15:38:23 -0800 Subject: [PATCH] linker: Sort shader I/O variables into a canonical order v2: Rebase on removal of ir_variable::user_location. Signed-off-by: Ian Romanick Reviewed-by: Eric Anholt --- src/glsl/link_varyings.cpp | 78 ++++++++++++++++++++++++++++++++++++-- 1 file changed, 74 insertions(+), 4 deletions(-) diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp index 85a8b90d7d6..e5c27516f56 100644 --- a/src/glsl/link_varyings.cpp +++ b/src/glsl/link_varyings.cpp @@ -1110,6 +1110,66 @@ get_matching_input(void *mem_ctx, } +static int +io_variable_cmp(const void *_a, const void *_b) +{ + const ir_variable *const a = *(const ir_variable **) _a; + const ir_variable *const b = *(const ir_variable **) _b; + + if (a->data.explicit_location && b->data.explicit_location) + return b->data.location - a->data.location; + + if (a->data.explicit_location && !b->data.explicit_location) + return 1; + + if (!a->data.explicit_location && b->data.explicit_location) + return -1; + + return -strcmp(a->name, b->name); +} + +/** + * Sort the shader IO variables into canonical order + */ +static void +canonicalize_shader_io(exec_list *ir, enum ir_variable_mode io_mode) +{ + ir_variable *var_table[MAX_PROGRAM_OUTPUTS * 4]; + unsigned num_variables = 0; + + foreach_list(node, ir) { + ir_variable *const var = ((ir_instruction *) node)->as_variable(); + + if (var == NULL || var->data.mode != io_mode) + continue; + + /* If we have already encountered more I/O variables that could + * successfully link, bail. + */ + if (num_variables == ARRAY_SIZE(var_table)) + return; + + var_table[num_variables++] = var; + } + + if (num_variables == 0) + return; + + /* Sort the list in reverse order (io_variable_cmp handles this). Later + * we're going to push the variables on to the IR list as a stack, so we + * want the last variable (in canonical order) to be first in the list. + */ + qsort(var_table, num_variables, sizeof(var_table[0]), io_variable_cmp); + + /* Remove the variable from it's current location in the IR, and put it at + * the front. + */ + for (unsigned i = 0; i < num_variables; i++) { + var_table[i]->remove(); + ir->push_head(var_table[i]); + } +} + /** * Assign locations for all variables that are produced in one pipeline stage * (the "producer") and consumed in the next stage (the "consumer"). @@ -1151,16 +1211,26 @@ assign_varying_locations(struct gl_context *ctx, hash_table *consumer_interface_inputs = hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare); - /* Operate in a total of three passes. + /* Operate in a total of four passes. * - * 1. Assign locations for any matching inputs and outputs. + * 1. Sort inputs / outputs into a canonical order. This is necessary so + * that inputs / outputs of separable shaders will be assigned + * predictable locations regardless of the order in which declarations + * appeared in the shader source. * - * 2. Mark output variables in the producer that do not have locations as + * 2. Assign locations for any matching inputs and outputs. + * + * 3. Mark output variables in the producer that do not have locations as * not being outputs. This lets the optimizer eliminate them. * - * 3. Mark input variables in the consumer that do not have locations as + * 4. Mark input variables in the consumer that do not have locations as * not being inputs. This lets the optimizer eliminate them. */ + if (consumer) + canonicalize_shader_io(consumer->ir, ir_var_shader_in); + + if (producer) + canonicalize_shader_io(producer->ir, ir_var_shader_out); if (consumer && !linker::populate_consumer_input_sets(mem_ctx, -- 2.30.2