Revert "perf: disable TSC snapshot compression (#18333)" (#18336)

This reverts commit 0d27de943a60f5ca60e2116648719c235163361a.

1 files changed, 15 insertions, 0 deletions

diff --git a/cli/build.rs b/cli/build.rs
index 251b30de2..ecd7ed1be 100644
--- a/cli/build.rs
+++ b/cli/build.rs
@@ -270,7 +270,22 @@ mod ts {
         build_libs,
         path_dts,
       )],
+
+      // NOTE(bartlomieju): Compressing the TSC snapshot in debug build took
+      // ~45s on M1 MacBook Pro; without compression it took ~1s.
+      // Thus we're not not using compressed snapshot, trading off
+      // a lot of build time for some startup time in debug build.
+      #[cfg(debug_assertions)]
       compression_cb: None,
+
+      #[cfg(not(debug_assertions))]
+      compression_cb: Some(Box::new(|vec, snapshot_slice| {
+        eprintln!("Compressing TSC snapshot...");
+        vec.extend_from_slice(
+          &zstd::bulk::compress(snapshot_slice, 22)
+            .expect("snapshot compression failed"),
+        );
+      })),
       snapshot_module_load_cb: None,
     });
   }