show-targets #36

crates/cargo-gpu/src/show.rs

@@ -1,5 +1,7 @@
 //! Display various information about `cargo gpu`, eg its cache directory.
 
+use std::process::{Command, Stdio};
+
 use crate::cache_dir;
 
 /// Show the computed source of the spirv-std dependency.
@@ -21,6 +23,9 @@ pub enum Info {
     Commitsh,
     /// All the available SPIR-V capabilities that can be set with `--capabilities`
     Capabilities,
+
+    /// All available SPIR-V targets
+    Targets,
 }
 
 /// `cargo gpu show`
@@ -63,6 +68,10 @@ impl Show {
                     println!("  {capability:?}");
                 }
             }
+            Info::Targets => {
+                let target_info = get_spirv_targets()?.join("\n");
+                println!("{}", target_info);
+            }
         }
 
         Ok(())
@@ -77,3 +86,42 @@ impl Show {
         (0..=last_capability).filter_map(spirv_builder::Capability::from_u32)
     }
 }
+
+/// Gets available SPIR-V targets by calling the `spirv-tools`' validator:
+/// ```sh
+/// $ spirv-val --version
+/// SPIRV-Tools v2022.2-dev unknown hash, 2022-02-16T16:37:15
+/// Targets:
+///   SPIR-V 1.0
+///   SPIR-V 1.1
+///   SPIR-V 1.2
+///   ... snip for brevity
+///  SPIR-V 1.6 (under Vulkan 1.3 semantics)
+///  ```
+fn get_spirv_targets() -> anyhow::Result<Vec<String>> {
+    // Defaults that have been tested, 1.2 is the existing default in the shader-crate-template.toml
+    let mut targets = vec![
+        "spirv-unknown-vulkan1.0",
+        "spirv-unknown-vulkan1.1",
+        "spirv-unknown-vulkan1.2",
+    ];
+
+    let output = Command::new("spirv-val")
+        .arg("--version")
+        .stdout(Stdio::piped())
+        .stderr(Stdio::piped())
+        .output();
+
+    if let Ok(output) = output {
+        let version_info = String::from_utf8_lossy(&output.stdout);
+        if version_info.contains("SPIR-V 1.3") {
+            targets.push("spirv-unknown-vulkan1.3");
+        }
+        if version_info.contains("SPIR-V 1.4") {
+            targets.push("spirv-unknown-vulkan1.4");
+        }
+        // Exhaustively, manually put in all possible versions? or regex them out?
+    }
+
+    Ok(targets.into_iter().map(String::from).collect())
+}