libiberty: Don't update and remove did_subs field from demangler structs.

The d_info field did_subs was used for estimating the string output
size. It was no longer used when the malloc-less callback interface
was introduced in 2007 (svn r121305). But the field was still updated.
When backtracking was introduced in 2013 (svn r205292) did_subs was
also added to the d_info_checkpoint struct. But except for updating
the field it was still not used.

Since it is never used just stop updating the field and remove it
from the two structs.

libiberty/ChangeLog:

	* cp-demangle.h (struct d_info): Remove did_subs field.
	* cp-demangle.c (struct d_info_checkpoint): Likewise.
	(d_template_param): Don't update did_subs.
	(d_substitution): Likewise.
	(d_checkpoint): Don't assign did_subs.
	(d_backtrack): Likewise.
	(cplus_demangle_init_info): Don't initialize did_subs.

From-SVN: r247054

libiberty/ChangeLog

+2017-04-21  Mark Wielaard  <mark@klomp.org>
+
+	* cp-demangle.h (struct d_info): Remove did_subs field.
+	* cp-demangle.c (struct d_info_checkpoint): Likewise.
+	(d_template_param): Don't update did_subs.
+	(d_substitution): Likewise.
+	(d_checkpoint): Don't assign did_subs.
+	(d_backtrack): Likewise.
+	(cplus_demangle_init_info): Don't initialize did_subs.
+
 2017-03-27  Pedro Alves  <palves@redhat.com>
 
 	* cp-demint.c (cplus_demangle_fill_component): Handle

libiberty/cp-demangle.c

@@ -316,7 +316,6 @@ struct d_info_checkpoint
   const char *n;
   int next_comp;
   int next_sub;
-  int did_subs;
   int expansion;
 };
 
@@ -3075,8 +3074,6 @@ d_template_param (struct d_info *di)
   if (param < 0)
     return NULL;
 
-  ++di->did_subs;
-
   return d_make_template_param (di, param);
 }
 
@@ -3846,8 +3843,6 @@ d_substitution (struct d_info *di, int prefix)
       if (id >= (unsigned int) di->next_sub)
 	return NULL;
 
-      ++di->did_subs;
-
       return di->subs[id];
     }
   else
@@ -3912,7 +3907,6 @@ d_checkpoint (struct d_info *di, struct d_info_checkpoint *checkpoint)
   checkpoint->n = di->n;
   checkpoint->next_comp = di->next_comp;
   checkpoint->next_sub = di->next_sub;
-  checkpoint->did_subs = di->did_subs;
   checkpoint->expansion = di->expansion;
 }
 
@@ -3922,7 +3916,6 @@ d_backtrack (struct d_info *di, struct d_info_checkpoint *checkpoint)
   di->n = checkpoint->n;
   di->next_comp = checkpoint->next_comp;
   di->next_sub = checkpoint->next_sub;
-  di->did_subs = checkpoint->did_subs;
   di->expansion = checkpoint->expansion;
 }
 
@@ -6159,7 +6152,6 @@ cplus_demangle_init_info (const char *mangled, int options, size_t len,
      chars in the mangled string.  */
   di->num_subs = len;
   di->next_sub = 0;
-  di->did_subs = 0;
 
   di->last_name = NULL;
 

libiberty/cp-demangle.h

@@ -111,10 +111,6 @@ struct d_info
   int next_sub;
   /* The number of available entries in the subs array.  */
   int num_subs;
-  /* The number of substitutions which we actually made from the subs
-     array, plus the number of template parameter references we
-     saw.  */
-  int did_subs;
   /* The last name we saw, for constructors and destructors.  */
   struct demangle_component *last_name;
   /* A running total of the length of large expansions from the