ZJIT: Remove obsoleted exit_trampoline (ruby#13943)

Author: k0kubun

zjit/src/state.rs

@@ -3,8 +3,6 @@ use crate::cruby_methods;
 use crate::invariants::Invariants;
 use crate::options::Options;
 use crate::asm::CodeBlock;
-use crate::backend::lir::{asm_comment, Assembler, C_RET_OPND};
-use crate::virtualmem::CodePtr;
 
 #[allow(non_upper_case_globals)]
 #[unsafe(no_mangle)]
@@ -31,9 +29,6 @@ pub struct ZJITState {
 
     /// Properties of core library methods
     method_annotations: cruby_methods::Annotations,
-
-    /// Trampoline to propagate a callee's side exit to the caller
-    exit_trampoline: Option<CodePtr>,
 }
 
 /// Private singleton instance of the codegen globals
@@ -88,14 +83,8 @@ impl ZJITState {
             invariants: Invariants::default(),
             assert_compiles: false,
             method_annotations: cruby_methods::init(),
-            exit_trampoline: None,
         };
         unsafe { ZJIT_STATE = Some(zjit_state); }
-
-        // Generate trampolines after initializing ZJITState, which Assembler will use
-        let cb = ZJITState::get_code_block();
-        let exit_trampoline = Self::gen_exit_trampoline(cb).unwrap();
-        ZJITState::get_instance().exit_trampoline = Some(exit_trampoline);
     }
 
     /// Return true if zjit_state has been initialized
@@ -137,20 +126,6 @@ impl ZJITState {
         let instance = ZJITState::get_instance();
         instance.assert_compiles = true;
     }
-
-    /// Generate a trampoline to propagate a callee's side exit to the caller
-    fn gen_exit_trampoline(cb: &mut CodeBlock) -> Option<CodePtr> {
-        let mut asm = Assembler::new();
-        asm_comment!(asm, "ZJIT exit trampoline");
-        asm.frame_teardown();
-        asm.cret(C_RET_OPND);
-        asm.compile(cb).map(|(start_ptr, _)| start_ptr)
-    }
-
-    /// Get the trampoline to propagate a callee's side exit to the caller
-    pub fn get_exit_trampoline() -> CodePtr {
-        ZJITState::get_instance().exit_trampoline.unwrap()
-    }
 }
 
 /// Initialize ZJIT, given options allocated by rb_zjit_init_options()