time: add specialized vpc_now_darwin to fix -os cross

vlib/time/time_darwin.c.v

@@ -36,3 +36,14 @@ fn sys_mono_now_darwin() u64 {
 	}
 	return (tm - start_time) * time_base.numer / time_base.denom
 }
+
+// NB: vpc_now_darwin is used by `v -profile` .
+// It should NOT call *any other v function*, just C functions and casts.
+[inline]
+fn vpc_now_darwin() u64 {
+	tm := C.mach_absolute_time()
+	if time_base.denom == 0 {
+		C.mach_timebase_info(&time_base)
+	}
+	return (tm - start_time) * time_base.numer / time_base.denom
+}

vlib/time/time_nix.c.v

@@ -43,15 +43,7 @@ fn sys_mono_now() u64 {
 // It should NOT call *any other v function*, just C functions and casts.
 [inline]
 fn vpc_now() u64 {
-	$if macos {
+	ts := C.timespec{}
-		tm := C.mach_absolute_time()
+	C.clock_gettime(C.CLOCK_MONOTONIC, &ts)
-		if time_base.denom == 0 {
+	return u64(ts.tv_sec) * 1_000_000_000 + u64(ts.tv_nsec)
-			C.mach_timebase_info(&time_base)
-		}
-		return (tm - start_time) * time_base.numer / time_base.denom
-	} $else {    
-		ts := C.timespec{}
-		C.clock_gettime(C.CLOCK_MONOTONIC, &ts)
-		return u64(ts.tv_sec) * 1_000_000_000 + u64(ts.tv_nsec)
-	}
 }

vlib/v/gen/profile.v

@@ -12,15 +12,16 @@ fn (mut g Gen) profile_fn(fn_name string, is_main bool){
 		g.writeln('\tatexit(vprint_profile_stats);')
 		g.writeln('')
 	}
-	if fn_name == 'time.vpc_now' {
+	if fn_name.starts_with('time.vpc_now') {
 		g.defer_profile_code = ''
 	} else {
+		measure_fn_name := if g.pref.os == .mac { 'time__vpc_now_darwin' } else { 'time__vpc_now' }
 		fn_profile_counter_name := 'vpc_${g.last_fn_c_name}'
 		fn_profile_counter_name_calls := '${fn_profile_counter_name}_calls'
 		g.writeln('')
-		g.writeln('\tdouble _PROF_FN_START = time__vpc_now(); ${fn_profile_counter_name_calls}++; // $fn_name')
+		g.writeln('\tdouble _PROF_FN_START = ${measure_fn_name}(); ${fn_profile_counter_name_calls}++; // $fn_name')
 		g.writeln('')
-		g.defer_profile_code = '\t${fn_profile_counter_name} += time__vpc_now() - _PROF_FN_START;'
+		g.defer_profile_code = '\t${fn_profile_counter_name} += ${measure_fn_name}() - _PROF_FN_START;'
 		g.pcs_declarations.writeln('double ${fn_profile_counter_name} = 0.0; u64 ${fn_profile_counter_name_calls} = 0;')
 		g.pcs << ProfileCounterMeta{ g.last_fn_c_name, fn_profile_counter_name, fn_profile_counter_name_calls }
 	}