compile_codegen: panic when rustc_codegen_spirv_location is not set

Author: Firestar99

crates/spirv-builder/src/lib.rs

@@ -606,6 +606,7 @@ fn dylib_path() -> Vec<PathBuf> {
     }
 }
 
+#[cfg(feature = "compile_codegen")]
 fn find_rustc_codegen_spirv() -> PathBuf {
     let filename = format!(
         "{}rustc_codegen_spirv{}",
@@ -621,6 +622,13 @@ fn find_rustc_codegen_spirv() -> PathBuf {
     panic!("Could not find {filename} in library path");
 }
 
+#[cfg(not(feature = "compile_codegen"))]
+fn find_rustc_codegen_spirv() -> PathBuf {
+    panic!(
+        "Without feature `compile_codegen`, you need to set the path of the codegen dylib using `rustc_codegen_spirv_location(...)`"
+    );
+}
+
 /// Joins strings together while ensuring none of the strings contain the separator.
 // NOTE(eddyb) this intentionally consumes the `Vec` to limit accidental misuse.
 fn join_checking_for_separators(strings: Vec<impl Borrow<str>>, sep: &str) -> String {