ZJIT: Add codegen for uncached setinstancevariable

Author: tekknolagi

test/ruby/test_zjit.rb

@@ -559,6 +559,15 @@ def test() = @foo
     }
   end
 
+  def test_setinstancevariable
+    assert_compiles '1', %q{
+      def test() = @foo = 1
+
+      test()
+      @foo
+    }
+  end
+
   # tool/ruby_vm/views/*.erb relies on the zjit instructions a) being contiguous and
   # b) being reliably ordered after all the other instructions.
   def test_instruction_order

zjit/bindgen/src/main.rs

@@ -381,6 +381,7 @@ fn main() {
         .allowlist_function("rb_attr_get")
         .allowlist_function("rb_ivar_defined")
         .allowlist_function("rb_ivar_get")
+        .allowlist_function("rb_ivar_set")
         .allowlist_function("rb_mod_name")
 
         // From include/ruby/internal/intern/vm.h

zjit/src/codegen.rs

@@ -275,6 +275,7 @@ fn gen_insn(cb: &mut CodeBlock, jit: &mut JITState, asm: &mut Assembler, functio
         Insn::PatchPoint(_) => return Some(()), // For now, rb_zjit_bop_redefined() panics. TODO: leave a patch point and fix rb_zjit_bop_redefined()
         Insn::CCall { cfun, args, name: _, return_type: _, elidable: _ } => gen_ccall(jit, asm, *cfun, args)?,
         Insn::GetIvar { self_val, id, state: _ } => gen_getivar(asm, opnd!(self_val), *id),
+        Insn::SetIvar { self_val, id, val, state: _ } => gen_setivar(asm, opnd!(self_val), *id, opnd!(val)),
         _ => {
             debug!("ZJIT: gen_function: unexpected insn {:?}", insn);
             return None;
@@ -307,6 +308,15 @@ fn gen_getivar(asm: &mut Assembler, recv: Opnd, id: ID) -> Opnd {
     )
 }
 
+/// Emit an uncached instance variable store
+fn gen_setivar(asm: &mut Assembler, recv: Opnd, id: ID, val: Opnd) -> Opnd {
+    asm_comment!(asm, "call rb_ivar_set");
+    asm.ccall(
+        rb_ivar_set as *const u8,
+        vec![recv, Opnd::UImm(id.0), val],
+    )
+}
+
 /// Compile an interpreter entry block to be inserted into an ISEQ
 fn gen_entry_prologue(asm: &mut Assembler, iseq: IseqPtr) {
     asm_comment!(asm, "ZJIT entry point: {}", iseq_get_location(iseq, 0));