glsl: Remove VS output varyings which are optimized out of the FS

Previously when an input varying was optimized out of the
FS we would still retain it as an output of the VS.

We now build a hash of live FS input varyings rather
than looking in the FS symbol table. (The FS symbol table
will still contain the optimized out varyings.)

Signed-off-by: Jordan Justen <jordan.l.justen@intel.com>
Reviewed-by: Paul Berry <stereotype441@gmail.com>
Reviewed-by: Kenneth Graunke <kenneth@whitecape.org>

diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
index b1317c8322be7e39c0101b4a2a696f9a1375805b..616933dfd3da9ef3afba83af02da2e9690c3e279 100644 (file)
--- a/src/glsl/link_varyings.cpp
+++ b/src/glsl/link_varyings.cpp
@@ -964,6 +964,8 @@ assign_varying_locations(struct gl_context *ctx,
    varying_matches matches(ctx->Const.DisableVaryingPacking);
    hash_table *tfeedback_candidates
       = hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare);
+   hash_table *consumer_inputs
+      = hash_table_ctor(0, hash_table_string_hash, hash_table_string_compare);
 
    /* Operate in a total of three passes.
     *
@@ -976,6 +978,18 @@ assign_varying_locations(struct gl_context *ctx,
     *    not being inputs.  This lets the optimizer eliminate them.
     */
 
+   if (consumer) {
+      foreach_list(node, consumer->ir) {
+         ir_variable *const input_var =
+            ((ir_instruction *) node)->as_variable();
+
+         if ((input_var != NULL) && (input_var->mode == ir_var_shader_in)) {
+            hash_table_insert(consumer_inputs, input_var,
+                              ralloc_strdup(mem_ctx, input_var->name));
+         }
+      }
+   }
+
    foreach_list(node, producer->ir) {
       ir_variable *const output_var = ((ir_instruction *) node)->as_variable();
 
@@ -986,7 +1000,7 @@ assign_varying_locations(struct gl_context *ctx,
       g.process(output_var);
 
       ir_variable *input_var =
-        consumer ? consumer->symbols->get_variable(output_var->name) : NULL;
+         (ir_variable *) hash_table_find(consumer_inputs, output_var->name);
 
       if (input_var && input_var->mode != ir_var_shader_in)
          input_var = NULL;
@@ -1005,6 +1019,7 @@ assign_varying_locations(struct gl_context *ctx,
 
       if (matched_candidate == NULL) {
          hash_table_dtor(tfeedback_candidates);
+         hash_table_dtor(consumer_inputs);
          return false;
       }
 
@@ -1021,11 +1036,13 @@ assign_varying_locations(struct gl_context *ctx,
 
       if (!tfeedback_decls[i].assign_location(ctx, prog)) {
          hash_table_dtor(tfeedback_candidates);
+         hash_table_dtor(consumer_inputs);
          return false;
       }
    }
 
    hash_table_dtor(tfeedback_candidates);
+   hash_table_dtor(consumer_inputs);
 
    if (ctx->Const.DisableVaryingPacking) {
       /* Transform feedback code assumes varyings are packed, so if the driver