ZJIT: Move jit_return clearing from rb_set_cfp_pc into codegen

The jit_return = 0 write in rb_set_cfp_pc was only needed by ZJIT.
Move it to the codegen call site next to where iseq is also set,
making the intent clearer.

1 files changed, 4 insertions, 2 deletions

diff --git a/zjit/src/codegen.rs b/zjit/src/codegen.rs
index 493033a6b1..c59dfbe525 100644
--- a/zjit/src/codegen.rs
+++ b/zjit/src/codegen.rs
@@ -3067,11 +3067,13 @@ c_callable! {
             let iseq_call = unsafe { Rc::from_raw(iseq_call_ptr as *const IseqCall) };
             let iseq = iseq_call.iseq.get();
             let entry_insn_idxs = crate::hir::jit_entry_insns(iseq);
-            // gen_push_frame() doesn't set PC, so we need to set them before exit.
-            // function_stub_hit_body() may allocate and call gc_validate_pc(), so we always set PC.
+            // gen_push_frame() doesn't set PC or ISEQ, so we need to set them before exit.
+            // function_stub_hit_body() may allocate and call gc_validate_pc(), so we always set PC and ISEQ.
+            // Clear jit_return so the interpreter reads cfp->pc and cfp->iseq directly.
             let pc = unsafe { rb_iseq_pc_at_idx(iseq, entry_insn_idxs[iseq_call.jit_entry_idx.to_usize()]) };
             unsafe { rb_set_cfp_pc(cfp, pc) };
             unsafe { (*cfp).iseq = iseq };
+            unsafe { (*cfp).jit_return = std::ptr::null_mut() };
         }
 
         with_vm_lock(src_loc!(), || {