Add preliminary support for Rust as an output format (via rust-gpu)

naga-cli/Cargo.toml

@@ -29,15 +29,16 @@ version = "0.19"
 path = "../naga"
 features = [
     "compact",
-    "wgsl-in",
-    "wgsl-out",
+    "dot-out",
     "glsl-in",
     "glsl-out",
-    "spv-in",
-    "spv-out",
     "msl-out",
     "hlsl-out",
-    "dot-out",
+    "rust-out",
+    "spv-in",
+    "spv-out",
+    "wgsl-in",
+    "wgsl-out",
     "serialize",
     "deserialize",
 ]

naga-cli/src/bin/naga.rs

@@ -655,6 +655,23 @@ fn write_output(
             .unwrap_pretty();
             fs::write(output_path, wgsl)?;
         }
+        "rs" => {
+            use naga::back::rust;
+
+            let rust = rust::write_string(
+                module,
+                info.as_ref().ok_or(CliError(
+                    "Generating Rust output requires validation to \
+                     succeed, and it failed in a previous step",
+                ))?,
+                // TODO: expose target via CLI.
+                rust::Target::Gpu,
+                rust::WriterFlags::empty(),
+            )
+            .unwrap_pretty();
+
+            fs::write(output_path, rust)?;
+        }
         other => {
             println!("Unknown output extension: {other}");
         }

naga/Cargo.toml

@@ -29,6 +29,7 @@ msl-out = []
 serialize = ["serde", "bitflags/serde", "indexmap/serde"]
 deserialize = ["serde", "bitflags/serde", "indexmap/serde"]
 arbitrary = ["dep:arbitrary", "bitflags/arbitrary", "indexmap/arbitrary"]
+rust-out = ["clone", "syn", "prettyplease", "proc-macro2", "quote"]
 spv-in = ["petgraph", "spirv"]
 spv-out = ["spirv"]
 wgsl-in = ["hexf-parse", "unicode-xid", "compact"]
@@ -60,6 +61,10 @@ petgraph = { version = "0.6", optional = true }
 pp-rs = { version = "0.2.1", optional = true }
 hexf-parse = { version = "0.2.1", optional = true }
 unicode-xid = { version = "0.2.3", optional = true }
+quote = { version = "1.0.35", optional = true }
+proc-macro2 = { version = "1.0.71", optional = true }
+syn = { version = "2.0.42", optional = true, features = ["full", "parsing"] }
+prettyplease = { version = "0.2.15", optional = true }
 arrayvec.workspace = true
 
 [target.'cfg(not(target_arch = "wasm32"))'.dev-dependencies]

naga/src/back/mod.rs

@@ -11,6 +11,8 @@ pub mod glsl;
 pub mod hlsl;
 #[cfg(feature = "msl-out")]
 pub mod msl;
+#[cfg(feature = "rust-out")]
+pub mod rust;
 #[cfg(feature = "spv-out")]
 pub mod spv;
 #[cfg(feature = "wgsl-out")]

naga/src/back/rust/mod.rs

@@ -0,0 +1,23 @@
+use prettyplease;
+pub mod writer;
+pub use writer::{Writer, WriterError, WriterFlags};
+
+#[cfg_attr(feature = "serialize", derive(serde::Serialize))]
+#[cfg_attr(feature = "deserialize", derive(serde::Deserialize))]
+#[derive(Debug, Clone, Default)]
+pub enum Target {
+    Cpu,
+    #[default]
+    Gpu,
+}
+
+pub fn write_string(
+    module: &crate::Module,
+    info: &crate::valid::ModuleInfo,
+    target: Target,
+    flags: WriterFlags,
+) -> Result<String, WriterError> {
+    let mut w = Writer::new(target, flags);
+    let file = w.write_module(module, info)?;
+    Ok(prettyplease::unparse(&file))
+}