nak: Add initial stubs for rust code

Part-of: <https://gitlab.freedesktop.org/mesa/mesa/-/merge_requests/24998>

src/nouveau/compiler/.editorconfig

@@ -0,0 +1,5 @@
+# To use this config on you editor, follow the instructions at:
+# http://editorconfig.org
+
+[*.rs]
+max_line_length = 80

src/nouveau/compiler/.rustfmt.toml

@@ -0,0 +1 @@
+max_width = 80

src/nouveau/compiler/meson.build

@@ -1,18 +1,62 @@
+add_languages('rust', required: true)
+rust = import('unstable-rust')
+
 libnak_c_files = files(
   'nak.h',
   'nak_nir.c',
 )
 
+libnak_rs_files = files(
+  'nak.rs',
+)
+
 libnak_deps = [
   idep_mesautil,
   idep_nir_headers,
 ]
 
+nak_bindings_rs = rust.bindgen(
+  input : ['nak.h'],
+  output : 'nak_bindings.rs',
+  args : [
+    '--allowlist-type', 'nak_.*',
+    '--allowlist-function', 'nak_.*',
+    '--allowlist-type', 'nir_shader',
+  ],
+)
+
+libnak_bindings_gen = static_library(
+  'nak_bindings',
+  nak_bindings_rs,
+  gnu_symbol_visibility : 'hidden',
+  rust_crate_type : 'rlib',
+)
+
+_libnak_rs = static_library(
+  'nak_rs',
+  [libnak_rs_files],
+  gnu_symbol_visibility : 'hidden',
+  rust_crate_type : 'staticlib',
+  rust_args : [
+    # we error on all clippy warnings unless they are disabled
+    '-Dclippy::all',
+    # we want to add asserts in control flow
+    '-Aclippy::assertions_on_constants',
+    # dunno, kind of looks nicier being explicit
+    '-Aclippy::redundant_field_names',
+    '-Aclippy::too_many_arguments',
+    '-Aclippy::type_complexity',
+    '-Anon_snake_case',
+  ],
+  link_with: [libnak_bindings_gen],
+)
+
 _libnak = static_library(
   'nak',
   libnak_c_files,
   include_directories : [inc_include, inc_src, inc_mapi, inc_mesa, inc_gallium],
   dependencies : libnak_deps,
+  link_with : [_libnak_rs],
   c_args : [no_override_init_args],
   gnu_symbol_visibility : 'hidden',
 )

src/nouveau/compiler/nak.h

@@ -43,6 +43,17 @@ struct nak_shader_info {
    uint32_t hdr[32];
 };
 
+struct nak_shader_bin {
+   struct nak_shader_info info;
+   uint32_t code_size;
+   const void *code;
+};
+
+void nak_shader_bin_destroy(struct nak_shader_bin *bin);
+
+struct nak_shader_bin *
+nak_compile_shader(nir_shader *nir, const struct nak_compiler *nak);
+
 #ifdef __cplusplus
 }
 #endif

src/nouveau/compiler/nak.rs

@@ -0,0 +1,28 @@
+/*
+ * Copyright © 2022 Collabora, Ltd.
+ * SPDX-License-Identifier: MIT
+ */
+
+use nak_bindings::*;
+
+#[repr(C)]
+struct ShaderBin {
+    bin: nak_shader_bin,
+    instrs: Vec<u32>,
+}
+
+#[no_mangle]
+pub extern "C" fn nak_shader_bin_destroy(bin: *mut nak_shader_bin) {
+    unsafe {
+        Box::from_raw(bin as *mut ShaderBin);
+    };
+}
+
+#[no_mangle]
+pub extern "C" fn nak_compile_shader(
+    _nir: *mut nir_shader,
+    _nak: *const nak_compiler,
+) -> *mut nak_shader_bin {
+    println!("Hello from rust!");
+    std::ptr::null_mut()
+}