change: split ArgcParamMismatch checks for positional and keyword args

Author: ykawabata17

zjit/src/hir.rs

@@ -1898,31 +1898,37 @@ fn can_direct_send(function: &mut Function, block: BlockId, iseq: *const rb_iseq
         return false;
     }
 
-    // Because we exclude e.g. post parameters above, they are also excluded from the sum below.
+    // Because we exclude e.g. post parameters above, they are also excluded from the checks below.
     let lead_num = params.lead_num;
     let opt_num = params.opt_num;
     let keyword = params.keyword;
     let kw_req_num = if keyword.is_null() { 0 } else { unsafe { (*keyword).required_num } };
     let kw_total_num = if keyword.is_null() { 0 } else { unsafe { (*keyword).num } };
-    // Minimum args: all required positional + all required keywords
-    let min_argc = lead_num + kw_req_num;
-    // Maximum args: all positional (required + optional) + all keywords (required + optional)
-    let max_argc = lead_num + opt_num + kw_total_num;
+    let kwarg = unsafe { rb_vm_ci_kwarg(ci) };
+    let caller_kw_count = if kwarg.is_null() { 0 } else { (unsafe { get_cikw_keyword_len(kwarg) }) as usize };
+    let caller_positional = match args.len().checked_sub(caller_kw_count) {
+        Some(count) => count,
+        None => {
+            function.set_dynamic_send_reason(send_insn, ArgcParamMismatch);
+            return false;
+        }
+    };
 
-    can_send = c_int::try_from(args.len())
+    let positional_ok = c_int::try_from(caller_positional)
         .as_ref()
-        .map(|argc| (min_argc..=max_argc).contains(argc))
+        .map(|argc| (lead_num..=lead_num + opt_num).contains(argc))
         .unwrap_or(false);
-    if !can_send {
+    let keyword_ok = c_int::try_from(caller_kw_count)
+        .as_ref()
+        .map(|argc| (kw_req_num..=kw_total_num).contains(argc))
+        .unwrap_or(false);
+    if !positional_ok || !keyword_ok {
         function.set_dynamic_send_reason(send_insn, ArgcParamMismatch);
         return false
     }
 
     // asm.ccall() doesn't support 6+ args. Compute the final argc after keyword setup:
     // final_argc = caller's positional args + callee's total keywords (all kw slots are filled).
-    let kwarg = unsafe { rb_vm_ci_kwarg(ci) };
-    let caller_kw_count = if kwarg.is_null() { 0 } else { (unsafe { get_cikw_keyword_len(kwarg) }) as usize };
-    let caller_positional = args.len() - caller_kw_count;
     // Right now, the JIT entrypoint accepts the block as an param
     // We may remove it, remove the block_arg addition to match
     // See: https://github.com/ruby/ruby/pull/15911#discussion_r2710544982
@@ -1933,15 +1939,6 @@ fn can_direct_send(function: &mut Function, block: BlockId, iseq: *const rb_iseq
         return false;
     }
 
-    // Caller passing a hash as a positional arg but callee expects keyword-only args will
-    // raise ArgumentError at runtime. Fall back to VM dispatch to handle this correctly.
-    if kwarg.is_null() && !keyword.is_null() {
-        if lead_num == 0 && opt_num == 0 && caller_positional > 0 {
-            function.set_dynamic_send_reason(send_insn, ArgcParamMismatch);
-            return false;
-        }
-    }
-
     can_send
 }