To: vim_dev@googlegroups.com
Subject: Patch 7.3.1140
Fcc: outbox
From: Bram Moolenaar <Bram@moolenaar.net>
Mime-Version: 1.0
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------------
 
Patch 7.3.1140
Problem:    New regexp engine: trying expensive match while the result is not
	    going to be used.
Solution:   Check for output state already being in the state list.
Files:	    src/regexp_nfa.c
 
 
*** ../vim-7.3.1139/src/regexp_nfa.c	2013-06-07 16:31:44.000000000 +0200
--- src/regexp_nfa.c	2013-06-07 17:16:31.000000000 +0200
***************
*** 3156,3161 ****
--- 3156,3163 ----
  static void copy_sub __ARGS((regsub_T *to, regsub_T *from));
  static void copy_sub_off __ARGS((regsub_T *to, regsub_T *from));
  static int sub_equal __ARGS((regsub_T *sub1, regsub_T *sub2));
+ static int has_state_with_pos __ARGS((nfa_list_T *l, nfa_state_T *state, regsubs_T *subs));
+ static int state_in_list __ARGS((nfa_list_T *l, nfa_state_T *state, regsubs_T *subs));
  static void addstate __ARGS((nfa_list_T *l, nfa_state_T *state, regsubs_T *subs, int off));
  static void addstate_here __ARGS((nfa_list_T *l, nfa_state_T *state, regsubs_T *subs, nfa_pim_T *pim, int *ip));
  
***************
*** 3319,3324 ****
--- 3321,3371 ----
  }
  #endif
  
+ /*
+  * Return TRUE if the same state is already in list "l" with the same
+  * positions as "subs".
+  */
+     static int
+ has_state_with_pos(l, state, subs)
+     nfa_list_T		*l;	/* runtime state list */
+     nfa_state_T		*state;	/* state to update */
+     regsubs_T		*subs;	/* pointers to subexpressions */
+ {
+     nfa_thread_T	*thread;
+     int			i;
+ 
+     for (i = 0; i < l->n; ++i)
+     {
+ 	thread = &l->t[i];
+ 	if (thread->state->id == state->id
+ 		&& sub_equal(&thread->subs.norm, &subs->norm)
+ #ifdef FEAT_SYN_HL
+ 		&& (!nfa_has_zsubexpr ||
+ 		       sub_equal(&thread->subs.synt, &subs->synt))
+ #endif
+ 			      )
+ 	    return TRUE;
+     }
+     return FALSE;
+ }
+ 
+ /*
+  * Return TRUE if "state" is already in list "l".
+  */
+     static int
+ state_in_list(l, state, subs)
+     nfa_list_T		*l;	/* runtime state list */
+     nfa_state_T		*state;	/* state to update */
+     regsubs_T		*subs;	/* pointers to subexpressions */
+ {
+     if (state->lastlist[nfa_ll_index] == l->id)
+     {
+ 	if (!nfa_has_backref || has_state_with_pos(l, state, subs))
+ 	    return TRUE;
+     }
+     return FALSE;
+ }
+ 
      static void
  addstate(l, state, subs, off)
      nfa_list_T		*l;	/* runtime state list */
***************
*** 3431,3450 ****
  		    return;
  		}
  
! 		/* See if the same state is already in the list with the same
! 		 * positions. */
! 		for (i = 0; i < l->n; ++i)
! 		{
! 		    thread = &l->t[i];
! 		    if (thread->state->id == state->id
! 			    && sub_equal(&thread->subs.norm, &subs->norm)
! #ifdef FEAT_SYN_HL
! 			    && (!nfa_has_zsubexpr ||
! 				   sub_equal(&thread->subs.synt, &subs->synt))
! #endif
! 					  )
! 			goto skip_add;
! 		}
  	    }
  
  	    /* when there are backreferences or look-behind matches the number
--- 3478,3485 ----
  		    return;
  		}
  
! 		if (has_state_with_pos(l, state, subs))
! 		    goto skip_add;
  	    }
  
  	    /* when there are backreferences or look-behind matches the number
***************
*** 4600,4605 ****
--- 4635,4681 ----
  		break;
  
  	    case NFA_START_PATTERN:
+ 	      {
+ 		nfa_state_T *skip = NULL;
+ #ifdef ENABLE_LOG
+ 		int	    skip_lid = 0;
+ #endif
+ 
+ 		/* There is no point in trying to match the pattern if the
+ 		 * output state is not going to be added to the list. */
+ 		if (state_in_list(nextlist, t->state->out1->out, &t->subs))
+ 		{
+ 		    skip = t->state->out1->out;
+ #ifdef ENABLE_LOG
+ 		    skip_lid = nextlist->id;
+ #endif
+ 		}
+ 		else if (state_in_list(nextlist,
+ 					  t->state->out1->out->out, &t->subs))
+ 		{
+ 		    skip = t->state->out1->out->out;
+ #ifdef ENABLE_LOG
+ 		    skip_lid = nextlist->id;
+ #endif
+ 		}
+ 		else if(state_in_list(thislist,
+ 					  t->state->out1->out->out, &t->subs))
+ 		{
+ 		    skip = t->state->out1->out->out;
+ #ifdef ENABLE_LOG
+ 		    skip_lid = thislist->id;
+ #endif
+ 		}
+ 		if (skip != NULL)
+ 		{
+ #ifdef ENABLE_LOG
+ 		    nfa_set_code(skip->c);
+ 		    fprintf(log_fd, "> Not trying to match pattern, output state %d is already in list %d. char %d: %s\n",
+ 			    abs(skip->id), skip_lid, skip->c, code);
+ #endif
+ 		    break;
+ 		}
+ 
  		/* First try matching the pattern. */
  		result = recursive_regmatch(t->state, prog,
  						       submatch, m, &listids);
***************
*** 4654,4659 ****
--- 4730,4736 ----
  		    }
  		}
  		break;
+ 	      }
  
  	    case NFA_BOL:
  		if (reginput == regline)
*** ../vim-7.3.1139/src/version.c	2013-06-07 16:31:45.000000000 +0200
--- src/version.c	2013-06-07 17:30:12.000000000 +0200
***************
*** 730,731 ****
--- 730,733 ----
  {   /* Add new patch number below this line */
+ /**/
+     1140,
  /**/
 
-- 
From "know your smileys":
 :-*	A big kiss!
 
 /// Bram Moolenaar -- Bram@Moolenaar.net -- http://www.Moolenaar.net   \\\
///        sponsor Vim, vote for features -- http://www.Vim.org/sponsor/ \\\
\\\  an exciting new programming language -- http://www.Zimbu.org        ///
 \\\            help me help AIDS victims -- http://ICCF-Holland.org    ///