ZJIT: Measure reading/writing locals with level > 0 (ruby#14601)

ZJIT: Measure writing to locals with level > 0

Author: tekknolagi

zjit.rb

@@ -64,6 +64,8 @@ def stats_string
       :vm_write_sp_count,
       :vm_write_locals_count,
       :vm_write_stack_count,
+      :vm_write_to_parent_iseq_local_count,
+      :vm_read_from_parent_iseq_local_count,
 
       :code_region_bytes,
       :side_exit_count,

zjit/src/codegen.rs

@@ -532,6 +532,9 @@ fn gen_defined(jit: &JITState, asm: &mut Assembler, op_type: usize, obj: VALUE,
 /// We generate this instruction with level=0 only when the local variable is on the heap, so we
 /// can't optimize the level=0 case using the SP register.
 fn gen_getlocal_with_ep(asm: &mut Assembler, local_ep_offset: u32, level: u32) -> lir::Opnd {
+    if level > 0 {
+        gen_incr_counter(asm, Counter::vm_read_from_parent_iseq_local_count);
+    }
     let ep = gen_get_ep(asm, level);
     let offset = -(SIZEOF_VALUE_I32 * i32::try_from(local_ep_offset).unwrap_or_else(|_| panic!("Could not convert local_ep_offset {local_ep_offset} to i32")));
     asm.load(Opnd::mem(64, ep, offset))
@@ -541,6 +544,9 @@ fn gen_getlocal_with_ep(asm: &mut Assembler, local_ep_offset: u32, level: u32) -
 /// We generate this instruction with level=0 only when the local variable is on the heap, so we
 /// can't optimize the level=0 case using the SP register.
 fn gen_setlocal_with_ep(asm: &mut Assembler, val: Opnd, val_type: Type, local_ep_offset: u32, level: u32) {
+    if level > 0 {
+        gen_incr_counter(asm, Counter::vm_write_to_parent_iseq_local_count);
+    }
     let ep = gen_get_ep(asm, level);
 
     // When we've proved that we're writing an immediate,

zjit/src/stats.rs

@@ -156,6 +156,10 @@ make_counters! {
     vm_write_sp_count,
     vm_write_locals_count,
     vm_write_stack_count,
+    vm_write_to_parent_iseq_local_count,
+    vm_read_from_parent_iseq_local_count,
+    // TODO(max): Implement
+    // vm_reify_stack_count,
 }
 
 /// Increase a counter by a specified amount