[Mesa-dev] [PATCH] glsl: mark explicit uniforms as explicit in other stages too

[Tapani Pälli]

If shader declares uniform explicit location in one stage but implicit in
another, explicit location should be used. Patch marks implicit uniforms
as explicit if they were explicit in another stage. This makes sure that
we don't treat them implicit later when assigning locations.

Fixes following CTS test:
   ES31-CTS.explicit_uniform_location.uniform-loc-implicit-in-some-stages3

Signed-off-by: Tapani Pälli <tapani.palli at intel.com>
---
 src/glsl/linker.cpp | 36 +++++++++++++++++++++++++++++++++++-
 1 file changed, 35 insertions(+), 1 deletion(-)

diff --git a/src/glsl/linker.cpp b/src/glsl/linker.cpp
index 564c471..70e701c 100644
--- a/src/glsl/linker.cpp
+++ b/src/glsl/linker.cpp
@@ -3131,11 +3131,33 @@ check_explicit_uniform_locations(struct gl_context *ctx,
     */
    string_to_uint_map *uniform_map = new string_to_uint_map;
 
-   if (!uniform_map) {
+   /* This map is used to validate that uniforms with explicit location are
+    * given the same explicit location properly across shader stages which
+    * reference the same uniform without explicit location qualifier.
+    */
+   string_to_uint_map *explicit_map = new string_to_uint_map;
+
+   if (!uniform_map || !explicit_map) {
       linker_error(prog, "Out of memory during linking.\n");
       return;
    }
 
+   /* A pass to generate hash that contains all uniforms where location
+    * has been set explicitly.
+    */
+   for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
+      struct gl_shader *sh = prog->_LinkedShaders[i];
+      if (!sh)
+         continue;
+      foreach_in_list(ir_instruction, node, sh->ir) {
+         ir_variable *var = node->as_variable();
+         if (!var || var->data.mode != ir_var_uniform ||
+             !var->data.explicit_location)
+            continue;
+         explicit_map->put(var->data.location, var->name);
+      }
+   }
+
    unsigned entries_total = 0;
    for (unsigned i = 0; i < MESA_SHADER_STAGES; i++) {
       struct gl_shader *sh = prog->_LinkedShaders[i];
@@ -3148,6 +3170,17 @@ check_explicit_uniform_locations(struct gl_context *ctx,
          if (!var || var->data.mode != ir_var_uniform)
             continue;
 
+         /* Check if this uniform with implicit location was marked explicit
+          * by any shader stage. If so, mark it explicit in this stage too to
+          * make sure later processing does not treat it as implicit one.
+          */
+         unsigned hash_loc;
+         if (!var->data.explicit_location &&
+             explicit_map->get(hash_loc, var->name)) {
+            var->data.explicit_location = 1;
+            var->data.location = hash_loc;
+         }
+
          entries_total += var->type->uniform_locations();
 
          if (var->data.explicit_location) {
@@ -3173,6 +3206,7 @@ check_explicit_uniform_locations(struct gl_context *ctx,
                    ctx->Const.MaxUserAssignableUniformLocations);
    }
    delete uniform_map;
+   delete explicit_map;
 }
 
 static bool
-- 
2.5.0