From c3404d736fa4fe7e330f3fbbeb4103f9206254d0 Mon Sep 17 00:00:00 2001
From: Max Bernstein <ruby@bernsteinbear.com>
Date: Wed, 22 Oct 2025 16:13:57 -0700
Subject: ZJIT: Use InvokeBuiltin leaf attribute in codegen

---
 zjit/src/codegen.rs | 12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

diff --git a/zjit/src/codegen.rs b/zjit/src/codegen.rs
index 848249d774..c00bdb474e 100644
--- a/zjit/src/codegen.rs
+++ b/zjit/src/codegen.rs
@@ -386,7 +386,7 @@ fn gen_insn(cb: &mut CodeBlock, jit: &mut JITState, asm: &mut Assembler, functio
         // Ensure we have enough room fit ec, self, and arguments
         // TODO remove this check when we have stack args (we can use Time.new to test it)
         Insn::InvokeBuiltin { bf, state, .. } if bf.argc + 2 > (C_ARG_OPNDS.len() as i32) => return Err(*state),
-        Insn::InvokeBuiltin { bf, args, state, .. } => gen_invokebuiltin(jit, asm, &function.frame_state(*state), bf, opnds!(args)),
+        Insn::InvokeBuiltin { bf, leaf, args, state, .. } => gen_invokebuiltin(jit, asm, &function.frame_state(*state), bf, *leaf, opnds!(args)),
         &Insn::EntryPoint { jit_entry_idx } => no_output!(gen_entry_point(jit, asm, jit_entry_idx)),
         Insn::Return { val } => no_output!(gen_return(asm, opnd!(val))),
         Insn::FixnumAdd { left, right, state } => gen_fixnum_add(jit, asm, opnd!(left), opnd!(right), &function.frame_state(*state)),
@@ -640,13 +640,17 @@ fn gen_get_constant_path(jit: &JITState, asm: &mut Assembler, ic: *const iseq_in
     asm_ccall!(asm, rb_vm_opt_getconstant_path, EC, CFP, Opnd::const_ptr(ic))
 }
 
-fn gen_invokebuiltin(jit: &JITState, asm: &mut Assembler, state: &FrameState, bf: &rb_builtin_function, args: Vec<Opnd>) -> lir::Opnd {
+fn gen_invokebuiltin(jit: &JITState, asm: &mut Assembler, state: &FrameState, bf: &rb_builtin_function, leaf: bool, args: Vec<Opnd>) -> lir::Opnd {
     assert!(bf.argc + 2 <= C_ARG_OPNDS.len() as i32,
             "gen_invokebuiltin should not be called for builtin function {} with too many arguments: {}",
             unsafe { std::ffi::CStr::from_ptr(bf.name).to_str().unwrap() },
             bf.argc);
-    // Anything can happen inside builtin functions
-    gen_prepare_non_leaf_call(jit, asm, state);
+    if leaf {
+        gen_prepare_leaf_call_with_gc(asm, state);
+    } else {
+        // Anything can happen inside builtin functions
+        gen_prepare_non_leaf_call(jit, asm, state);
+    }
 
     let mut cargs = vec![EC];
     cargs.extend(args);
-- 
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