From: Ian Romanick <ian.d.roman...@intel.com>
Signed-off-by: Ian Romanick <ian.d.roman...@intel.com>
---
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 065e234..3d9516c 100644
--- a/src/glsl/link_varyings.cpp
+++ b/src/glsl/link_varyings.cpp
@@ -1111,6 +1111,66 @@ 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.user_location != -1 && b->data.user_location != -1)
+ return b->data.user_location - a->data.user_location;
+
+ if (a->data.user_location != -1 && b->data.user_location == -1)
+ return 1;
+
+ if (a->data.user_location == -1 && b->data.user_location != -1)
+ 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").
@@ -1154,16 +1214,26 @@ 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,
--
1.8.1.4
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