nir/spirv: handle kernel function parameters

the idea here is to generate an entry point stub function wrapping around the
actual kernel function and turn all parameters into shader inputs with byte
addressing instead of vec4.

This gives us several advantages:
1. calling kernel functions doesn't differ from calling any other function
2. CL inputs match uniforms in most ways and we can just take advantage of most
   of nir_lower_io

v2: move code into a seperate function
v3: verify the entry point got a name
    fix minor typo
v4: make vtn_emit_kernel_entry_point_wrapper take the old entry point as an arg

Signed-off-by: Karol Herbst <kherbst@redhat.com>

diff --git a/src/compiler/spirv/spirv_to_nir.c b/src/compiler/spirv/spirv_to_nir.c
index 5becd3418da6a9d59529f8aed30dd79d9313b890..df5bba2c2a03be085c45c59e9061318c7d58cfe2 100644 (file)
--- a/src/compiler/spirv/spirv_to_nir.c
+++ b/src/compiler/spirv/spirv_to_nir.c
@@ -4453,6 +4453,68 @@ vtn_create_builder(const uint32_t *words, size_t word_count,
    return NULL;
 }
 
+static nir_function *
+vtn_emit_kernel_entry_point_wrapper(struct vtn_builder *b,
+                                    const nir_function *entry_point)
+{
+   vtn_assert(entry_point == b->entry_point->func->impl->function);
+   vtn_fail_if(!entry_point->name, "entry points are required to have a name");
+   const char *func_name =
+      ralloc_asprintf(b->shader, "__wrapped_%s", entry_point->name);
+
+   /* we shouldn't have any inputs yet */
+   vtn_assert(!entry_point->shader->num_inputs);
+   vtn_assert(b->shader->info.stage == MESA_SHADER_KERNEL);
+
+   nir_function *main_entry_point = nir_function_create(b->shader, func_name);
+   main_entry_point->impl = nir_function_impl_create(main_entry_point);
+   nir_builder_init(&b->nb, main_entry_point->impl);
+   b->nb.cursor = nir_after_cf_list(&main_entry_point->impl->body);
+   b->func_param_idx = 0;
+
+   nir_call_instr *call = nir_call_instr_create(b->nb.shader, entry_point);
+
+   for (unsigned i = 0; i < entry_point->num_params; ++i) {
+      struct vtn_type *param_type = b->entry_point->func->type->params[i];
+
+      /* consider all pointers to function memory to be parameters passed
+       * by value
+       */
+      bool is_by_val = param_type->base_type == vtn_base_type_pointer &&
+         param_type->storage_class == SpvStorageClassFunction;
+
+      /* input variable */
+      nir_variable *in_var = rzalloc(b->nb.shader, nir_variable);
+      in_var->data.mode = nir_var_shader_in;
+      in_var->data.read_only = true;
+      in_var->data.location = i;
+
+      if (is_by_val)
+         in_var->type = param_type->deref->type;
+      else
+         in_var->type = param_type->type;
+
+      nir_shader_add_variable(b->nb.shader, in_var);
+      b->nb.shader->num_inputs++;
+
+      /* we have to copy the entire variable into function memory */
+      if (is_by_val) {
+         nir_variable *copy_var =
+            nir_local_variable_create(main_entry_point->impl, in_var->type,
+                                      "copy_in");
+         nir_copy_var(&b->nb, copy_var, in_var);
+         call->params[i] =
+            nir_src_for_ssa(&nir_build_deref_var(&b->nb, copy_var)->dest.ssa);
+      } else {
+         call->params[i] = nir_src_for_ssa(nir_load_var(&b->nb, in_var));
+      }
+   }
+
+   nir_builder_instr_insert(&b->nb, &call->instr);
+
+   return main_entry_point;
+}
+
 nir_function *
 spirv_to_nir(const uint32_t *words, size_t word_count,
              struct nir_spirv_specialization *spec, unsigned num_spec,
@@ -4542,6 +4604,10 @@ spirv_to_nir(const uint32_t *words, size_t word_count,
    nir_function *entry_point = b->entry_point->func->impl->function;
    vtn_assert(entry_point);
 
+   /* post process entry_points with input params */
+   if (entry_point->num_params && b->shader->info.stage == MESA_SHADER_KERNEL)
+      entry_point = vtn_emit_kernel_entry_point_wrapper(b, entry_point);
+
    entry_point->is_entrypoint = true;
 
    /* When multiple shader stages exist in the same SPIR-V module, we