d3d12, microsoft/compiler: Use SRV/sampler variable binding data

For GL, we've previously mostly ignored the binding property for sampler variables
during the shader compilation step. For CL, our image bindings were always 0-based as well.

Now, for Vulkan, we are going to be getting explicit bindings and need to emit DXIL that
respects those bindings. Since Vulkan can also have both split and combined images and samplers,
we now need to be smarter about recognizing when NIR is trying to use a "sampler" as *both* an
image and sampler (in deref mode, the same variable will be deref'd as both image and sampler).

That "being smarter" bit comes next, but first, let's prep GL for building correct root
signatures and binding the resources correctly.

Reviewed-By: Bill Kristiansen <billkris@microsoft.com>
Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/10298>

src/microsoft/compiler/nir_to_dxil.c

@@ -793,9 +793,10 @@ get_resource_id(struct ntd_context *ctx, enum dxil_resource_class class,
 }
 
 static bool
-emit_srv(struct ntd_context *ctx, nir_variable *var, unsigned binding, unsigned count)
+emit_srv(struct ntd_context *ctx, nir_variable *var, unsigned count)
 {
    unsigned id = util_dynarray_num_elements(&ctx->srv_metadata_nodes, const struct dxil_mdnode *);
+   unsigned binding = var->data.binding;
    resource_array_layout layout = {id, binding, count};
 
    enum dxil_component_type comp_type;
@@ -1099,9 +1100,10 @@ emit_ubo_var(struct ntd_context *ctx, nir_variable *var)
 }
 
 static bool
-emit_sampler(struct ntd_context *ctx, nir_variable *var, unsigned binding, unsigned count)
+emit_sampler(struct ntd_context *ctx, nir_variable *var, unsigned count)
 {
    unsigned id = util_dynarray_num_elements(&ctx->sampler_metadata_nodes, const struct dxil_mdnode *);
+   unsigned binding = var->data.binding;
    resource_array_layout layout = {id, binding, count};
    const struct dxil_type *int32_type = dxil_module_get_int_type(&ctx->mod, 32);
    const struct dxil_type *sampler_type = dxil_module_get_struct_type(&ctx->mod, "struct.SamplerState", &int32_type, 1);
@@ -4287,8 +4289,6 @@ shader_has_shared_ops(struct nir_shader *s)
 static bool
 emit_module(struct ntd_context *ctx, const struct nir_to_dxil_options *opts)
 {
-   unsigned binding;
-
    /* The validator forces us to emit resources in a specific order:
     * CBVs, Samplers, SRVs, UAVs. While we are at it also remove
     * stale struct uniforms, they are lowered but might not have been removed */
@@ -4299,26 +4299,22 @@ emit_module(struct ntd_context *ctx, const struct nir_to_dxil_options *opts)
       return false;
 
    /* Samplers */
-   binding = 0;
    nir_foreach_variable_with_modes(var, ctx->shader, nir_var_uniform) {
       unsigned count = glsl_type_get_sampler_count(var->type);
       if (var->data.mode == nir_var_uniform && count &&
           glsl_get_sampler_result_type(glsl_without_array(var->type)) == GLSL_TYPE_VOID) {
-         if (!emit_sampler(ctx, var, binding, count))
+         if (!emit_sampler(ctx, var, count))
             return false;
-         binding += count;
       }
    }
 
    /* SRVs */
-   binding = 0;
    nir_foreach_variable_with_modes(var, ctx->shader, nir_var_uniform) {
       unsigned count = glsl_type_get_sampler_count(var->type);
       if (var->data.mode == nir_var_uniform && count &&
           glsl_get_sampler_result_type(glsl_without_array(var->type)) != GLSL_TYPE_VOID) {
-         if (!emit_srv(ctx, var, binding, count))
+         if (!emit_srv(ctx, var, count))
             return false;
-         binding += count;
       }
    }