Replace debug assertions check with optimization level check for benchmarks

Co-authored-by: ludfjig <[email protected]>

Author: Copilot

src/hyperlight_host/benches/benchmarks.rs

@@ -14,12 +14,12 @@ See the License for the specific language governing permissions and
 limitations under the License.
 */
 
-// Benchmarks are only meaningful and should only run with release builds.
-// Debug builds have different performance characteristics and would not provide
+// Benchmarks are only meaningful and should only run with optimized builds.
+// Unoptimized builds have different performance characteristics and would not provide
 // useful benchmarking data for performance regression testing.
-#[cfg(debug_assertions)]
+#[cfg(unoptimized_build)]
 compile_error!(
-    "Benchmarks must be run with release builds only. Use `cargo bench --release` or `just bench`."
+    "Benchmarks must be run with optimized builds only. Use `cargo bench --release` or `just bench`."
 );
 
 use criterion::{Criterion, criterion_group, criterion_main};

src/hyperlight_host/build.rs

@@ -85,6 +85,24 @@ fn main() -> Result<()> {
         );
     }
 
+    // Set a cfg flag based on optimization level for benchmarks
+    // Benchmarks should only run with optimized builds (opt-level 1+)
+    println!("cargo:rustc-check-cfg=cfg(unoptimized_build)");
+    println!("cargo:rustc-check-cfg=cfg(optimized_build)");
+    
+    if let Ok(opt_level) = std::env::var("OPT_LEVEL") {
+        if opt_level == "0" {
+            // Unoptimized build - benchmarks should not run
+            println!("cargo:rustc-cfg=unoptimized_build");
+        } else {
+            // Optimized build - benchmarks can run
+            println!("cargo:rustc-cfg=optimized_build");
+        }
+    } else {
+        // Fallback: if we can't determine opt level, assume unoptimized to be safe
+        println!("cargo:rustc-cfg=unoptimized_build");
+    }
+
     // Makes #[cfg(kvm)] == #[cfg(all(feature = "kvm", target_os = "linux"))]
     // and #[cfg(mshv)] == #[cfg(all(any(feature = "mshv2", feature = "mshv3"), target_os = "linux"))].
     // Essentially the kvm and mshv features are ignored on windows as long as you use #[cfg(kvm)] and not #[cfg(feature = "kvm")].