ZJIT: Replace GuardShape with LoadField+GuadBitEquals

Only thing left to do here is fixup the reason so the stats stay the
same

Author: tekknolagi

zjit/src/codegen.rs

@@ -2052,6 +2052,7 @@ fn gen_guard_bit_equals(jit: &mut JITState, asm: &mut Assembler, val: lir::Opnd,
     let expected_opnd: Opnd = match expected {
         crate::hir::Const::Value(v) => { Opnd::Value(v) }
         crate::hir::Const::CInt64(v) => { v.into() }
+        crate::hir::Const::CShape(v) => { Opnd::UImm(v.0 as u64) }
         _ => panic!("gen_guard_bit_equals: unexpected hir::Const {expected:?}"),
     };
     asm.cmp(val, expected_opnd);

zjit/src/hir.rs

@@ -3056,6 +3056,15 @@ impl Function {
         self.infer_types();
     }
 
+    fn load_shape(&mut self, block: BlockId, recv: InsnId) -> InsnId {
+        self.push_insn(block, Insn::LoadField {
+            recv,
+            id: ID!(_shape_id),
+            offset: unsafe { rb_shape_id_offset() } as i32,
+            return_type: types::CShape
+        })
+    }
+
     fn optimize_getivar(&mut self) {
         for block in self.rpo() {
             let old_insns = std::mem::take(&mut self.blocks[block.0].insns);
@@ -3081,7 +3090,8 @@ impl Function {
                             self.push_insn_id(block, insn_id); continue;
                         }
                         let self_val = self.push_insn(block, Insn::GuardType { val: self_val, guard_type: types::HeapBasicObject, state });
-                        let self_val = self.push_insn(block, Insn::GuardShape { val: self_val, shape: recv_type.shape(), state });
+                        let shape = self.load_shape(block, self_val);
+                        self.push_insn(block, Insn::GuardBitEquals { val: shape, expected: Const::CShape(recv_type.shape()), state });
                         let mut ivar_index: u16 = 0;
                         let replacement = if ! unsafe { rb_shape_get_iv_index(recv_type.shape().0, id, &mut ivar_index) } {
                             // If there is no IVAR index, then the ivar was undefined when we
@@ -3135,7 +3145,8 @@ impl Function {
                             self.push_insn_id(block, insn_id); continue;
                         }
                         let self_val = self.push_insn(block, Insn::GuardType { val: self_val, guard_type: types::HeapBasicObject, state });
-                        let _ = self.push_insn(block, Insn::GuardShape { val: self_val, shape: recv_type.shape(), state });
+                        let shape = self.load_shape(block, self_val);
+                        self.push_insn(block, Insn::GuardBitEquals { val: shape, expected: Const::CShape(recv_type.shape()), state });
                         let mut ivar_index: u16 = 0;
                         let replacement = if unsafe { rb_shape_get_iv_index(recv_type.shape().0, id, &mut ivar_index) } {
                             self.push_insn(block, Insn::Const { val: Const::Value(pushval) })
@@ -3206,7 +3217,8 @@ impl Function {
                             // Fall through to emitting the ivar write
                         }
                         let self_val = self.push_insn(block, Insn::GuardType { val: self_val, guard_type: types::HeapBasicObject, state });
-                        let self_val = self.push_insn(block, Insn::GuardShape { val: self_val, shape: recv_type.shape(), state });
+                        let shape = self.load_shape(block, self_val);
+                        self.push_insn(block, Insn::GuardBitEquals { val: shape, expected: Const::CShape(recv_type.shape()), state });
                         // Current shape contains this ivar
                         let (ivar_storage, offset) = if recv_type.flags().is_embedded() {
                             // See ROBJECT_FIELDS() from include/ruby/internal/core/robject.h