diff --git a/src/vim9.h b/src/vim9.h
index 8d4faa3..9446c15 100644
--- a/src/vim9.h
+++ b/src/vim9.h
@@ -152,6 +152,9 @@
     ISN_CMDMOD,	    // set cmdmod
     ISN_CMDMOD_REV, // undo ISN_CMDMOD
 
+    ISN_PROF_START, // start a line for profiling
+    ISN_PROF_END,   // end a line for profiling
+
     ISN_UNPACK,	    // unpack list into items, uses isn_arg.unpack
     ISN_SHUFFLE,    // move item on stack up or down
     ISN_DROP	    // pop stack and discard value
@@ -366,8 +369,12 @@
 				    // was compiled.
 
     garray_T	df_def_args_isn;    // default argument instructions
+
+    // After compiling "df_instr" and/or "df_instr_prof" is not NULL.
     isn_T	*df_instr;	    // function body to be executed
-    int		df_instr_count;
+    int		df_instr_count;	    // size of "df_instr"
+    isn_T	*df_instr_prof;		// like "df_instr" with profiling
+    int		df_instr_prof_count;	// size of "df_instr_prof"
 
     int		df_varcount;	    // number of local variables
     int		df_has_closure;	    // one if a closure was created