From 4f56abbb0a3e25972b246fa516718520e5cd27e9 Mon Sep 17 00:00:00 2001
From: Randy Stauner <randy@r4s6.net>
Date: Wed, 5 Nov 2025 12:08:28 -0700
Subject: ZJIT: Don't side-exit on VM_CALL_KWARG just SendWithoutBlock (#15065)

---
 zjit/src/hir.rs           |  6 +++---
 zjit/src/hir/opt_tests.rs | 10 ++++++++--
 zjit/src/hir/tests.rs     |  4 +++-
 3 files changed, 14 insertions(+), 6 deletions(-)

diff --git a/zjit/src/hir.rs b/zjit/src/hir.rs
index b26d2ffa04..9762a87dd4 100644
--- a/zjit/src/hir.rs
+++ b/zjit/src/hir.rs
@@ -2286,7 +2286,7 @@ impl Function {
                         };
                         let ci = unsafe { get_call_data_ci(cd) }; // info about the call site
 
-                        // If the call site info indicates that the `Function` has `VM_CALL_ARGS_SPLAT` set, then
+                        // If the call site info indicates that the `Function` has overly complex arguments, then
                         // do not optimize into a `SendWithoutBlockDirect`.
                         let flags = unsafe { rb_vm_ci_flag(ci) };
                         if unspecializable_call_type(flags) {
@@ -4265,13 +4265,13 @@ fn num_locals(iseq: *const rb_iseq_t) -> usize {
 
 /// If we can't handle the type of send (yet), bail out.
 fn unhandled_call_type(flags: u32) -> Result<(), CallType> {
-    if (flags & VM_CALL_KWARG) != 0 { return Err(CallType::Kwarg); }
     if (flags & VM_CALL_TAILCALL) != 0 { return Err(CallType::Tailcall); }
     Ok(())
 }
 
-/// If a given call uses splatting or block arguments, then we won't specialize.
+/// If a given call uses overly complex arguments, then we won't specialize.
 fn unspecializable_call_type(flags: u32) -> bool {
+    ((flags & VM_CALL_KWARG) != 0) ||
     ((flags & VM_CALL_ARGS_SPLAT) != 0) ||
     ((flags & VM_CALL_ARGS_BLOCKARG) != 0)
 }
diff --git a/zjit/src/hir/opt_tests.rs b/zjit/src/hir/opt_tests.rs
index 6fc890f385..f824351eca 100644
--- a/zjit/src/hir/opt_tests.rs
+++ b/zjit/src/hir/opt_tests.rs
@@ -2659,7 +2659,10 @@ mod hir_opt_tests {
           Jump bb2(v4)
         bb2(v6:BasicObject):
           v10:Fixnum[1] = Const Value(1)
-          SideExit UnhandledCallType(Kwarg)
+          IncrCounter complex_arg_pass_caller_kwarg
+          v12:BasicObject = SendWithoutBlock v6, :foo, v10
+          CheckInterrupts
+          Return v12
         ");
     }
 
@@ -2682,7 +2685,10 @@ mod hir_opt_tests {
           Jump bb2(v4)
         bb2(v6:BasicObject):
           v10:Fixnum[1] = Const Value(1)
-          SideExit UnhandledCallType(Kwarg)
+          IncrCounter complex_arg_pass_caller_kwarg
+          v12:BasicObject = SendWithoutBlock v6, :foo, v10
+          CheckInterrupts
+          Return v12
         ");
     }
 
diff --git a/zjit/src/hir/tests.rs b/zjit/src/hir/tests.rs
index fe67779d85..a8738a0715 100644
--- a/zjit/src/hir/tests.rs
+++ b/zjit/src/hir/tests.rs
@@ -1572,7 +1572,9 @@ pub mod hir_build_tests {
           Jump bb2(v5, v6)
         bb2(v8:BasicObject, v9:BasicObject):
           v13:Fixnum[1] = Const Value(1)
-          SideExit UnhandledCallType(Kwarg)
+          v15:BasicObject = SendWithoutBlock v8, :foo, v13
+          CheckInterrupts
+          Return v15
         ");
     }
 
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