fix(compile): keep force-unwind-tables when auto-optimize sets RUSTFLAGS

changelog.d/7315-auto-optimize-unwind-tables.md

@@ -0,0 +1 @@
+- fix(compile): auto-optimize no longer strips the runtime's unwind tables. Setting `RUSTFLAGS` for the rebuild replaced `.cargo/config.toml`'s `[build] rustflags`, the only place `-C force-unwind-tables=yes` lives, so any auto-optimized binary aborted on the first `throw` crossing a runtime frame. The flag is now appended explicitly, except under `panic_immediate` which deliberately wants the tables gone. (#7315)

crates/perry/src/commands/compile/optimized_libs/driver.rs

@@ -955,6 +955,13 @@ pub(crate) fn build_optimized_libs(
     // RUSTFLAGS from the parent environment, which is exactly the isolation a
     // pinned-baseline build needs.
     if !rustflags.is_empty() || requested_cpu.is_some() {
+        // #7315: setting RUSTFLAGS here replaces `.cargo/config.toml`'s
+        // `[build] rustflags`, which is where `-C force-unwind-tables=yes`
+        // lives. Without it the rebuilt runtime has no unwind tables and the
+        // first `throw` that crosses a runtime frame aborts.
+        if !panic_immediate {
+            rustflags.push("-C force-unwind-tables=yes".to_string());
+        }
         cargo_cmd.env("RUSTFLAGS", rustflags.join(" "));
     }