nir: add support for pixel_local_storage variables

Reviewed-by: Marek Olšák <marek.olsak@amd.com>
Reviewed-by: Boris Brezillon <boris.brezillon@collabora.com>
Reviewed-by: Eric R. Smith <eric.smith@collabora.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/37110>

src/compiler/glsl_types.h

@@ -466,6 +466,11 @@ struct glsl_struct_field {
           */
          unsigned precision:2;
 
+         /**
+          * Pixel local storage qualifier
+          */
+         unsigned pixel_local_storage:2;
+
          /**
           * Memory qualifiers, applicable to buffer variables defined in shader
           * storage buffer objects (SSBOs)

src/compiler/nir/nir.c

@@ -256,6 +256,9 @@ nir_shader_add_variable(nir_shader *shader, nir_variable *var)
    case nir_var_mem_node_payload:
    case nir_var_mem_node_payload_in:
    case nir_var_mem_global:
+   case nir_var_mem_pixel_local_in:
+   case nir_var_mem_pixel_local_out:
+   case nir_var_mem_pixel_local_inout:
       break;
 
    default:

src/compiler/nir/nir.h

@@ -448,7 +448,7 @@ typedef struct nir_variable {
        *
        * :c:struct:`nir_variable_mode`
        */
-      unsigned mode : 21;
+      unsigned mode : 24;
 
       /**
        * Is the variable read-only?

src/compiler/nir/nir_defines.h

@@ -76,18 +76,21 @@ typedef enum {
    nir_var_mem_task_payload      = (1 << 11),
    nir_var_mem_node_payload      = (1 << 12),
    nir_var_mem_node_payload_in   = (1 << 13),
+   nir_var_mem_pixel_local_in    = (1 << 14),
+   nir_var_mem_pixel_local_out   = (1 << 15),
+   nir_var_mem_pixel_local_inout = (1 << 16),
 
-   nir_var_function_in           = (1 << 14),
-   nir_var_function_out          = (1 << 15),
-   nir_var_function_inout        = (1 << 16),
+   nir_var_function_in           = (1 << 17),
+   nir_var_function_out          = (1 << 18),
+   nir_var_function_inout        = (1 << 19),
 
    /* Generic modes intentionally come last. See encode_dref_modes() in
     * nir_serialize.c for more details.
     */
-   nir_var_shader_temp           = (1 << 17),
-   nir_var_function_temp         = (1 << 18),
-   nir_var_mem_shared            = (1 << 19),
-   nir_var_mem_global            = (1 << 20),
+   nir_var_shader_temp           = (1 << 20),
+   nir_var_function_temp         = (1 << 21),
+   nir_var_mem_shared            = (1 << 22),
+   nir_var_mem_global            = (1 << 23),
 
    nir_var_mem_generic           = (nir_var_shader_temp |
                                     nir_var_function_temp |
@@ -105,7 +108,13 @@ typedef enum {
                                  nir_var_mem_shared | nir_var_mem_global |
                                  nir_var_mem_push_const | nir_var_mem_task_payload |
                                  nir_var_shader_out | nir_var_system_value,
-   nir_num_variable_modes        = 21,
+
+   /* modes that can serve as fragment shader outputs */
+   nir_var_any_pixel_local   = nir_var_mem_pixel_local_in |
+                               nir_var_mem_pixel_local_out |
+                               nir_var_mem_pixel_local_inout,
+
+   nir_num_variable_modes        = 24,
    nir_var_all                   = (1 << nir_num_variable_modes) - 1,
 } nir_variable_mode;
 MESA_DEFINE_CPP_ENUM_BITFIELD_OPERATORS(nir_variable_mode)

src/compiler/nir/nir_gather_info.c

@@ -514,6 +514,9 @@ gather_intrinsic_info(nir_intrinsic_instr *instr, nir_shader *shader)
       }
       if (nir_intrinsic_writes_external_memory(instr))
          shader->info.writes_memory = true;
+      if (shader->info.stage == MESA_SHADER_FRAGMENT &&
+          nir_deref_mode_is_one_of(deref, nir_var_any_pixel_local))
+         shader->info.fs.accesses_pixel_local_storage = true;
       break;
    }
    case nir_intrinsic_image_deref_load:
@@ -1049,6 +1052,7 @@ nir_shader_gather_info(nir_shader *shader, nir_function_impl *entrypoint)
       shader->info.vs.double_inputs = 0;
    }
    if (shader->info.stage == MESA_SHADER_FRAGMENT) {
+      shader->info.fs.accesses_pixel_local_storage = false;
       shader->info.fs.uses_sample_qualifier = false;
       shader->info.fs.uses_discard = false;
       shader->info.fs.color_is_dual_source = false;

src/compiler/nir/nir_print.c

@@ -752,6 +752,12 @@ get_variable_mode_str(nir_variable_mode mode, bool want_local_global_mode)
       return "push_const";
    case nir_var_mem_constant:
       return "constant";
+   case nir_var_mem_pixel_local_in:
+      return "pixel_local_in";
+   case nir_var_mem_pixel_local_out:
+      return "pixel_local_out";
+   case nir_var_mem_pixel_local_inout:
+      return "pixel_local";
    case nir_var_image:
       return "image";
    case nir_var_shader_temp:
@@ -1054,6 +1060,11 @@ print_deref_link(const nir_deref_instr *instr, bool whole_chain, print_state *st
    case nir_deref_type_struct:
       fprintf(fp, "%s%s", is_parent_pointer ? "->" : ".",
               glsl_get_struct_elem_name(parent->type, instr->strct.index));
+      if (whole_chain &&
+          parent->type->fields.structure[instr->strct.index].pixel_local_storage) {
+         fprintf(fp, " (%s)",
+                 util_format_short_name(parent->type->fields.structure[instr->strct.index].image_format));
+      }
       break;
 
    case nir_deref_type_array:

src/compiler/nir/nir_validate.c

@@ -2284,6 +2284,9 @@ nir_validate_shader(nir_shader *shader, const char *when)
       nir_var_mem_global |
       nir_var_mem_push_const |
       nir_var_mem_constant |
+      nir_var_mem_pixel_local_in |
+      nir_var_mem_pixel_local_out |
+      nir_var_mem_pixel_local_inout |
       nir_var_image;
 
    if (mesa_shader_stage_is_callable(shader->info.stage))

src/compiler/shader_info.h

@@ -459,6 +459,11 @@ typedef struct shader_info {
          bool sample_interlock_ordered:1;
          bool sample_interlock_unordered:1;
 
+         /**
+          * whether this shader has pixel_local_storage load/store instructions
+          */
+         bool accesses_pixel_local_storage:1;
+
          /**
           * Flags whether NIR's base types on the FS color outputs should be
           * ignored.