[Mesa-dev] [PATCH 2/4] nir/lower_io: Make variable location assignment a manual operation

[Jason Ekstrand]

Previously, we just assigned variable locations in nir_lower_io.  Now, we
force the user to assign variable locations for us.  This gives the backend
a bit more control over where variables are placed.
---
 src/glsl/nir/nir.h                       |  3 +++
 src/glsl/nir/nir_lower_io.c              | 14 ++------------
 src/mesa/drivers/dri/i965/brw_fs_nir.cpp |  4 ++++
 3 files changed, 9 insertions(+), 12 deletions(-)

diff --git a/src/glsl/nir/nir.h b/src/glsl/nir/nir.h
index 6b42df9..0015ec2 100644
--- a/src/glsl/nir/nir.h
+++ b/src/glsl/nir/nir.h
@@ -1577,6 +1577,9 @@ void nir_lower_global_vars_to_local(nir_shader *shader);
 
 void nir_lower_locals_to_regs(nir_shader *shader);
 
+void nir_assign_var_locations_packed(struct exec_list *var_list,
+                                     unsigned *size);
+
 void nir_lower_io(nir_shader *shader);
 
 void nir_lower_vars_to_ssa(nir_shader *shader);
diff --git a/src/glsl/nir/nir_lower_io.c b/src/glsl/nir/nir_lower_io.c
index 37c357e..d57b5b1 100644
--- a/src/glsl/nir/nir_lower_io.c
+++ b/src/glsl/nir/nir_lower_io.c
@@ -76,8 +76,8 @@ type_size(const struct glsl_type *type)
    return 0;
 }
 
-static void
-assign_var_locations(struct exec_list *var_list, unsigned *size)
+void
+nir_assign_var_locations_packed(struct exec_list *var_list, unsigned *size)
 {
    unsigned location = 0;
 
@@ -96,14 +96,6 @@ assign_var_locations(struct exec_list *var_list, unsigned *size)
    *size = location;
 }
 
-static void
-assign_var_locations_shader(nir_shader *shader)
-{
-   assign_var_locations(&shader->inputs, &shader->num_inputs);
-   assign_var_locations(&shader->outputs, &shader->num_outputs);
-   assign_var_locations(&shader->uniforms, &shader->num_uniforms);
-}
-
 static bool
 deref_has_indirect(nir_deref_var *deref)
 {
@@ -304,8 +296,6 @@ nir_lower_io_impl(nir_function_impl *impl)
 void
 nir_lower_io(nir_shader *shader)
 {
-   assign_var_locations_shader(shader);
-
    nir_foreach_overload(shader, overload) {
       if (overload->impl)
          nir_lower_io_impl(overload->impl);
diff --git a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
index 777914e..c316088 100644
--- a/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
+++ b/src/mesa/drivers/dri/i965/brw_fs_nir.cpp
@@ -106,6 +106,10 @@ fs_visitor::emit_nir_code()
    /* Get rid of split copies */
    nir_optimize(nir);
 
+   nir_assign_var_locations_packed(&nir->uniforms, &nir->num_uniforms);
+   nir_assign_var_locations_packed(&nir->inputs, &nir->num_inputs);
+   nir_assign_var_locations_packed(&nir->outputs, &nir->num_outputs);
+
    nir_lower_io(nir);
    nir_validate_shader(nir);
 
-- 
2.3.2