glsl: tidy up struct with a single member

There used to be more members but they now share other fields
in order to keep memory use low.

Also making the naming more generic will allow us to reuse the
field for explicit byte offsets within blocks for
ARB_enhanced_layouts.

Reviewed-by: Edward O'Callaghan <eocallaghan@alterapraxis.com>

src/glsl/ast_to_hir.cpp

@@ -3105,7 +3105,7 @@ apply_layout_qualifier_to_variable(const struct ast_type_qualifier *qual,
                _mesa_glsl_error(loc, state,
                                 "misaligned atomic counter offset");
 
-            var->data.atomic.offset = *offset;
+            var->data.offset = *offset;
             *offset += var->type->atomic_size();
 
          } else {

src/glsl/ir.cpp

@@ -1674,7 +1674,7 @@ ir_variable::ir_variable(const struct glsl_type *type, const char *name,
    this->data.mode = mode;
    this->data.interpolation = INTERP_QUALIFIER_NONE;
    this->data.max_array_access = 0;
-   this->data.atomic.offset = 0;
+   this->data.offset = 0;
    this->data.precision = GLSL_PRECISION_NONE;
    this->data.image_read_only = false;
    this->data.image_write_only = false;

src/glsl/ir.h

@@ -871,9 +871,7 @@ public:
       /**
        * Location an atomic counter is stored at.
        */
-      struct {
-         unsigned offset;
-      } atomic;
+      unsigned offset;
 
       /**
        * Highest element accessed with a constant expression array index

src/glsl/link_atomics.cpp

@@ -83,16 +83,16 @@ namespace {
       const active_atomic_counter *const first = (active_atomic_counter *) a;
       const active_atomic_counter *const second = (active_atomic_counter *) b;
 
-      return int(first->var->data.atomic.offset) - int(second->var->data.atomic.offset);
+      return int(first->var->data.offset) - int(second->var->data.offset);
    }
 
    bool
    check_atomic_counters_overlap(const ir_variable *x, const ir_variable *y)
    {
-      return ((x->data.atomic.offset >= y->data.atomic.offset &&
-               x->data.atomic.offset < y->data.atomic.offset + y->type->atomic_size()) ||
-              (y->data.atomic.offset >= x->data.atomic.offset &&
-               y->data.atomic.offset < x->data.atomic.offset + x->type->atomic_size()));
+      return ((x->data.offset >= y->data.offset &&
+               x->data.offset < y->data.offset + y->type->atomic_size()) ||
+              (y->data.offset >= x->data.offset &&
+               y->data.offset < x->data.offset + x->type->atomic_size()));
    }
 
    void
@@ -158,7 +158,7 @@ namespace {
             ir_variable *var = node->as_variable();
 
             if (var && var->type->contains_atomic()) {
-               int offset = var->data.atomic.offset;
+               int offset = var->data.offset;
                unsigned uniform_loc = var->data.location;
                process_atomic_variable(var->type, prog, &uniform_loc,
                                        var, buffers, num_buffers, &offset, i);
@@ -185,7 +185,7 @@ namespace {
                linker_error(prog, "Atomic counter %s declared at offset %d "
                             "which is already in use.",
                             buffers[i].counters[j].var->name,
-                            buffers[i].counters[j].var->data.atomic.offset);
+                            buffers[i].counters[j].var->data.offset);
             }
          }
       }
@@ -237,7 +237,7 @@ link_assign_atomic_counter_resources(struct gl_context *ctx,
             var->data.binding = i;
 
          storage->atomic_buffer_index = i;
-         storage->offset = var->data.atomic.offset;
+         storage->offset = var->data.offset;
          storage->array_stride = (var->type->is_array() ?
                                   var->type->without_array()->atomic_size() : 0);
          if (!var->type->is_matrix())

src/glsl/linker.cpp

@@ -1014,7 +1014,7 @@ cross_validate_globals(struct gl_shader_program *prog,
             }
 
             if (var->type->contains_atomic() &&
-                var->data.atomic.offset != existing->data.atomic.offset) {
+                var->data.offset != existing->data.offset) {
                linker_error(prog, "offset specifications for %s "
                             "`%s' have differing values\n",
                             mode_string(var), var->name);

src/glsl/nir/glsl_to_nir.cpp

@@ -389,7 +389,7 @@ nir_visitor::visit(ir_variable *ir)
 
    var->data.index = ir->data.index;
    var->data.binding = ir->data.binding;
-   var->data.atomic.offset = ir->data.atomic.offset;
+   var->data.offset = ir->data.offset;
    var->data.image.read_only = ir->data.image_read_only;
    var->data.image.write_only = ir->data.image_write_only;
    var->data.image.coherent = ir->data.image_coherent;

src/glsl/nir/nir.h

@@ -291,9 +291,7 @@ typedef struct {
       /**
        * Location an atomic counter is stored at.
        */
-      struct {
-         unsigned offset;
-      } atomic;
+      unsigned offset;
 
       /**
        * ARB_shader_image_load_store qualifiers.

src/glsl/nir/nir_lower_atomics.c

@@ -74,7 +74,7 @@ lower_instr(nir_intrinsic_instr *instr,
       state->shader_program->UniformStorage[uniform_loc].opaque[state->shader->stage].index;
 
    nir_load_const_instr *offset_const = nir_load_const_instr_create(mem_ctx, 1);
-   offset_const->value.u[0] = instr->variables[0]->var->data.atomic.offset;
+   offset_const->value.u[0] = instr->variables[0]->var->data.offset;
 
    nir_instr_insert_before(&instr->instr, &offset_const->instr);