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 <[email protected]>
Reviewed-by: Paul Berry <[email protected]>
Reviewed-by: Kenneth Graunke <[email protected]>

1 files changed, 18 insertions, 1 deletions

diff --git a/src/glsl/link_varyings.cpp b/src/glsl/link_varyings.cpp
index b1317c8322b..616933dfd3d 100644
--- 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