[fixme] workaround verilator bad TOP scope

difftest/online_dpi/src/dpi.rs

@@ -282,7 +282,8 @@ pub(crate) fn dump_wave(path: &str) {
   use crate::svdpi;
   let path_cstring = CString::new(path).unwrap();
 
-  svdpi::set_scope_by_name("TOP.TestBench.clockGen");
+  // TODO: use vcs/verialtor/... feature to select features, verilator always has a TOP scope
+  svdpi::set_scope_by_name("TestBench.clockGen");
   unsafe {
     dpi_export::dump_wave(path_cstring.as_ptr());
   }

difftest/t1dpi.nix

@@ -0,0 +1,54 @@
+{ lib
+, libspike
+, callPackage
+, elaborateConfig
+
+, rustPlatform
+
+, rust-analyzer
+, rust-bindgen
+
+, verilator
+, verilated
+, cmake
+, clang-tools
+}:
+
+let
+  spike_interfaces = callPackage ./spike_interfaces { };
+
+  src = with lib.fileset; toSource {
+    root = ./.;
+    fileset = unions [
+      ./spike_rs
+      ./offline
+      ./online_dpi
+      ./online_drive
+      ./online_vcs
+      ./test_common
+      ./Cargo.lock
+      ./Cargo.toml
+    ];
+  };
+
+  env = {
+    SPIKE_LIB_DIR = "${libspike}/lib";
+    SPIKE_INTERFACES_LIB_DIR = "${spike_interfaces}/lib";
+    DESIGN_VLEN = elaborateConfig.parameter.vLen;
+    DESIGN_DLEN = elaborateConfig.parameter.dLen;
+  };
+
+  self = rustPlatform.buildRustPackage {
+    name = "online-dpi-lib";
+
+    inherit src env;
+
+    cargoLock = {
+      lockFile = ./Cargo.lock;
+    };
+
+    buildFeatures = lib.optionals verilated.enable-trace [ "trace" ];
+    buildAndTestSubdir = "./online_vcs";
+  };
+in
+self