b4_yaxx macro enables saving parsing trees into XML, tested on 1.875-3.0.4, see https://github.com/yijunyu/yaxx

* origin/maint:
  maint: post-release administrivia
  version 3.0.4
  gnulib: update
  build: re-enable compiler warnings, and fix them
  tests: c++: fix a C++03 conformance issue
  tests: fix a title
  c++: reserve 200 slots in the parser's stack
  tests: be more robust to unrecognized synclines, and try to recognize xlc
  tests: fix C++ conformance
  build: fix some warnings
  build: avoid infinite recursions on include_next

.prev-version

@@ -1 +1 @@
-3.0.3
+3.0.4

NEWS

@@ -1,5 +1,50 @@
 GNU Bison NEWS
 
+* Noteworthy changes in release ?.? (????-??-??) [?]
+
+** Diagnostics about useless rules
+
+  In the following grammar, the 'exp' nonterminal is trivially useless.  So,
+  of course, its rules are useless too.
+
+    %%
+    input: '0' | exp
+    exp: exp '+' exp | exp '-' exp | '(' exp ')'
+
+  Previously all the useless rules were reported, including those whose
+  left-hand side is the 'exp' nonterminal:
+
+    warning: 1 nonterminal useless in grammar [-Wother]
+    warning: 4 rules useless in grammar [-Wother]
+    2.14-16: warning: nonterminal useless in grammar: exp [-Wother]
+     input: '0' | exp
+                  ^^^
+    2.14-16: warning: rule useless in grammar [-Wother]
+     input: '0' | exp
+                  ^^^
+    3.6-16: warning: rule useless in grammar [-Wother]
+     exp: exp '+' exp | exp '-' exp | '(' exp ')'
+          ^^^^^^^^^^^
+    3.20-30: warning: rule useless in grammar [-Wother]
+     exp: exp '+' exp | exp '-' exp | '(' exp ')'
+                        ^^^^^^^^^^^
+    3.34-44: warning: rule useless in grammar [-Wother]
+     exp: exp '+' exp | exp '-' exp | '(' exp ')'
+                                      ^^^^^^^^^^^
+
+  Now, rules whose left-hand side symbol is useless are no longer reported
+  as useless.  The locations of the errors have also been adjusted to point
+  to the first use of the nonterminal as a left-hand side of a rule:
+
+    warning: 1 nonterminal useless in grammar [-Wother]
+    warning: 4 rules useless in grammar [-Wother]
+    3.1-3: warning: nonterminal useless in grammar: exp [-Wother]
+     exp: exp '+' exp | exp '-' exp | '(' exp ')'
+     ^^^
+    2.14-16: warning: rule useless in grammar [-Wother]
+     input: '0' | exp
+                  ^^^
+
 * Noteworthy changes in release 3.0.4 (2015-01-23) [stable]
 
 ** Bug fixes

data/glr.c

@@ -1692,7 +1692,7 @@ yyreportAmbiguity (yySemanticOption* yyx0,
  *  ending at YYS1.  Has no effect on previously resolved states.
  *  The first semantic option of a state is always chosen.  */
 static void
-yyresolveLocations (yyGLRState* yys1, int yyn1,
+yyresolveLocations (yyGLRState *yys1, int yyn1,
                     yyGLRStack *yystackp]b4_user_formals[)
 {
   if (0 < yyn1)
@@ -1703,9 +1703,9 @@ yyresolveLocations (yyGLRState* yys1, int yyn1,
           yyGLRStackItem yyrhsloc[1 + YYMAXRHS];
           int yynrhs;
           yySemanticOption *yyoption = yys1->yysemantics.yyfirstVal;
-          YYASSERT (yyoption != YY_NULLPTR);
+          YYASSERT (yyoption);
           yynrhs = yyrhsLength (yyoption->yyrule);
-          if (yynrhs > 0)
+          if (0 < yynrhs)
             {
               yyGLRState *yys;
               int yyn;
@@ -1728,18 +1728,7 @@ yyresolveLocations (yyGLRState* yys1, int yyn1,
               yyGLRState *yyprevious = yyoption->yystate;
               yyrhsloc[0].yystate.yyloc = yyprevious->yyloc;
             }
-          {
+          YYLLOC_DEFAULT ((yys1->yyloc), yyrhsloc, yynrhs);
-            int yychar_current = yychar;
-            YYSTYPE yylval_current = yylval;
-            YYLTYPE yylloc_current = yylloc;
-            yychar = yyoption->yyrawchar;
-            yylval = yyoption->yyval;
-            yylloc = yyoption->yyloc;
-            YYLLOC_DEFAULT ((yys1->yyloc), yyrhsloc, yynrhs);
-            yychar = yychar_current;
-            yylval = yylval_current;
-            yylloc = yylloc_current;
-          }
         }
     }
 }]])[

data/yacc.c

@@ -52,6 +52,8 @@ m4_define([b4_lac_flag],
                  [none], [[0]], [[1]])])
 
 m4_include(b4_pkgdatadir/[c.m4])
+m4_define([b4_yaxx],[$1])
+m4_define([b4_not_yaxx],[])
 
 ## ---------------- ##
 ## Default values.  ##
@@ -331,7 +333,11 @@ m4_if(b4_api_prefix, [yy], [],
 #define yydebug         ]b4_prefix[debug
 #define yynerrs         ]b4_prefix[nerrs
 ]]b4_pure_if([], [[
-#define yylval          ]b4_prefix[lval
+#define yylval          ]b4_prefix[lval]b4_yaxx([
+#define yytext  	]b4_prefix[text
+#define YYYAXX_XML  "b4_prefix[]yaxx.xml"
+#define YYYAXX_DTD  "b4_prefix[]yaxx.dtd"
+])[
 #define yychar          ]b4_prefix[char]b4_locations_if([[
 #define yylloc          ]b4_prefix[lloc]])]))[
 
@@ -420,6 +426,10 @@ typedef short int yytype_int16;
 /* The parser invokes alloca or malloc; define the necessary symbols.  */]dnl
 b4_push_if([], [b4_lac_if([], [[
 
+]b4_yaxx([
+#define XML_ALLOC(X) malloc(X)
+#define XML_FREE(X) free(X)
+])[
 # ifdef YYSTACK_USE_ALLOCA
 #  if YYSTACK_USE_ALLOCA
 #   ifdef __GNUC__
@@ -494,7 +504,7 @@ void free (void *); /* INFRINGES ON USER NAME SPACE */
 union yyalloc
 {
   yytype_int16 yyss_alloc;
-  YYSTYPE yyvs_alloc;]b4_locations_if([
+  YYSTYPE yyvs_alloc;]b4_yaxx([char *yyxs_alloc;])[]b4_locations_if([
   YYLTYPE yyls_alloc;])[
 };
 
@@ -505,10 +515,10 @@ union yyalloc
    N elements.  */
 ]b4_locations_if(
 [# define YYSTACK_BYTES(N) \
-     ((N) * (sizeof (yytype_int16) + sizeof (YYSTYPE) + sizeof (YYLTYPE)) \
+     ((N) * (sizeof (yytype_int16) + sizeof (YYSTYPE) + sizeof (YYLTYPE) ]b4_yaxx([+ sizeof(char*) ])[) \
       + 2 * YYSTACK_GAP_MAXIMUM)],
 [# define YYSTACK_BYTES(N) \
-     ((N) * (sizeof (yytype_int16) + sizeof (YYSTYPE)) \
+     ((N) * (sizeof (yytype_int16) + sizeof (YYSTYPE) ]b4_yaxx([+ sizeof(char*) ])[) \
       + YYSTACK_GAP_MAXIMUM)])[
 
 # define YYCOPY_NEEDED 1
@@ -580,19 +590,27 @@ static const ]b4_int_type_for([b4_translate])[ yytranslate[] =
   ]b4_translate[
 };
 
+]b4_not_yaxx([
 #if ]b4_api_PREFIX[DEBUG
+])[
 ]b4_integral_parser_table_define([rline], [b4_rline],
      [[YYRLINE[YYN] -- Source line where rule number YYN was defined.]])[
+]b4_not_yaxx([
 #endif
+])[
 
+]b4_not_yaxx([
 #if ]b4_api_PREFIX[DEBUG || YYERROR_VERBOSE || ]b4_token_table_flag[
+])[
 /* YYTNAME[SYMBOL-NUM] -- String name of the symbol SYMBOL-NUM.
    First, the terminals, then, starting at YYNTOKENS, nonterminals.  */
 static const char *const yytname[] =
 {
   ]b4_tname[
 };
+]b4_not_yaxx([
 #endif
+])
 
 # ifdef YYPRINT
 /* YYTOKNUM[NUM] -- (External) token number corresponding to the
@@ -1366,7 +1384,194 @@ b4_function_define([[yyparse]], [[int]], b4_parse_param)[
   [[[YYSTYPE const *yypushed_val]], [[yypushed_val]]]b4_locations_if([,
   [[[YYLTYPE *yypushed_loc]], [[yypushed_loc]]]])])m4_ifset([b4_parse_param], [,
   b4_parse_param]))], [[
+]b4_yaxx([
+extern char *b4_prefix[]text;
+// Yijun Yu: utility functions -----------------------------------------------
+#include <stdio.h>
+#include <string.h>
+#include <stdlib.h>
+#include <stddef.h>
+/// replace character terminals into symbolic terminals
+static char *YYTNAME(int r)
+{
+  static char yytname_buf[[8]];
+  if (strlen(yytname[[r]])==3 && yytname[[r]][[0]] == '\'' && yytname[[r]][[2]] == '\'') 
+  { 
+        sprintf(yytname_buf, "CHAR%d", (int)yytname[[r]][[1]]);
+        return yytname_buf;
+  } 
+  else if (strlen(yytname[[r]])>=2 && yytname[[r]][[0]] == 64 )
+  {
+    strcpy(yytname_buf,"ACTION");
+    strcat(yytname_buf,&(yytname[[r]][[1]]));
+    return yytname_buf;
+  }
 
+  return (char *)yytname[[r]];
+}
+#include <stdio.h>
+#include <stddef.h>
+static char *yytext_buf = NULL;
+
+/// replace a special character in the text into an entity
+static
+void replace_entity(char c, char *s)
+{
+    char *buf;
+    char *i;
+    int len, l;
+    i = yytext_buf;
+    do {
+        i =  (char *)index(i, c);
+        if (i) {
+            l = i - yytext_buf;
+            len = strlen(yytext_buf) + strlen(s) - 1;
+            //buf = (char*)YYSTACK_ALLOC(1000000);
+            buf = (char*)YYSTACK_ALLOC(len + 1); // Myo M Thein
+            if (l>0) {
+#if 1 // Myo M Thein
+		strncpy(buf, yytext_buf, l);
+#else
+		int t = 0;
+		while (t < l) {
+			buf[t] = yytext_buf[t]; 
+			t++;
+		}
+                buf[t] = 0;
+#endif
+            } else {
+                buf[[0]] = 0;
+            }
+            strcat(buf, s); 
+            strncat(buf, yytext_buf + l + 1, strlen(yytext_buf) - l); 
+            buf[[len]] = 0;
+            YYSTACK_FREE(yytext_buf); 
+            //yytext_buf = buf;
+	    memcpy(yytext_buf,buf,len+1);
+        i++;
+        if (*i=='\0')
+            i=NULL;
+        }
+    } while (i);
+}
+
+/// replace the special characters in the text into entities 
+static
+char* xml_encode( char ch)
+{
+  static char text[[2]];
+    switch(ch)
+    {
+    case '&':
+        return ( "&amp;");
+        break;
+    case '>':
+        return ( "&gt;");
+        break;
+    case '<' :
+        return ( "&lt;" );
+        break;
+    case  '\"':
+        return ( "&quot;");
+        break;
+    case '\'':
+        return ( "&apos;");
+        break;
+    default:
+        text[[0]]=ch;
+        text[[1]]=0;
+        return text;
+        break;
+    }
+}
+
+static
+void replace_special_entities(char *text,char *text_out)
+{
+  int i,lg;
+    if (!text) { strcpy(text_out,"??");return ; }
+    lg = strlen(text);
+    strcpy(text_out,"");
+    for (i=0;i<lg;i++)
+    {
+       strcat(text_out,xml_encode(text[[i]]));
+    }
+}
+static
+void generate_xml_output(char **yyxsp,char **yyxs)
+{
+#ifndef YYYAXX_XML 
+#define YYYAXX_XML  "yaxx.xml"
+#endif
+#ifndef YYYAXX_DTD
+#define YYYAXX_DTD "yaxx.dtd"
+#endif
+       int r, i, j;
+       char buf[[2000]];
+       int old_rule = 0;
+       FILE *stdout = fopen(YYYAXX_XML, "w");
+       char *p = *yyxsp + 6;
+#if 0
+       char *v = strsep(&p, ">");
+       strcpy(buf, v);
+#else
+	   i = 0;
+	   while (p[[i]]!='>') {
+		buf[[i]] = p[[i]];
+		i++;
+	   }
+	   buf[[i]]  = 0;
+#endif
+       /// Generating the XML document 
+       /// version 
+       fprintf(stdout,"<?xml version=\"1.0\"?>\n");
+       /// DTD reference
+       fprintf(stdout,"<?xml-stylesheet type=\"text/xsl\" href=\"yaxx.xsl\"?>");
+       fprintf(stdout,"<!DOCTYPE %s SYSTEM \"" YYYAXX_DTD "\">\n", buf);
+       /// inserting name space before the XML data
+       fprintf(stdout,"<yaxx:%s xmlns:yaxx=\"urn:YAcc-Xml-eXtension\"%s\n", buf,
+            yyxs[[1]]+i+6); //ffprintf(stdout,f, "%s\n", yyxs[[1]]);
+       /// Generating the document type definition (DTD) 
+       stdout = fopen(YYYAXX_DTD , "w");
+       /// DTD for non-terminals
+       for (r = 2; r < sizeof(yyr1)/sizeof(unsigned short); r++) 
+       {
+        j = yyr1[[r]];
+        if (j != old_rule) {
+        	if (old_rule!=0)
+        		fprintf(stdout,")>\n");
+	        fprintf(stdout,"<!ELEMENT %s (", YYTNAME(yyr1[[r]]));
+        } else
+	    	fprintf(stdout," | ");
+        if (yyr2[[r]]==0) 
+           fprintf(stdout,"EMPTY");
+        else {
+		/*
+        	int multiple = 0;
+            for (i = yyprhs[[r]]; yyrhs[[i]] > 0 ; i++)
+               if (i!=yyprhs[[r]]) {
+               	multiple = 1; break;
+               }
+       		if (multiple) fprintf(stdout,"(");
+            for (i = yyprhs[[r]]; yyrhs[[i]] > 0 ; i++) {
+               if (i!=yyprhs[[r]])
+                   fprintf(stdout,",");
+               fprintf(stdout,"%s", YYTNAME(yyrhs[[i]]));
+            }
+       		if (multiple) fprintf(stdout,")");
+		 */
+         }
+         old_rule = j;
+       }
+       fprintf(stdout,")>\n");
+       /// DTD for terminals
+       for (r = 3; r < YYNTOKENS; r++) 
+       {
+            fprintf(stdout,"<!ELEMENT %s (#PCDATA)>\n", YYTNAME(r));
+       }
+    
+}
+])[
 
 /*----------.
 | yyparse.  |
@@ -1398,7 +1603,26 @@ b4_function_define([[yyparse]], [[int]], b4_parse_param)[
   YYSIZE_T yymsg_alloc = sizeof yymsgbuf;
 #endif
 
+]b4_yaxx([
+
+  /* The tags stack. */
+  char *yyxsa[[YYINITDEPTH]];
+  char **yyxs = yyxsa;
+  char **yyxsp;
+])[
 #define YYPOPSTACK(N)   (yyvsp -= (N), yyssp -= (N)]b4_locations_if([, yylsp -= (N)])[)
+]b4_yaxx([
+#include <stdio.h>
+#include <string.h>
+#undef __GNUC_PREREQ
+#define __GNUC_PREREQ(maj, min) (maj < 4)
+#include <stdlib.h>
+#include <stddef.h>
+static char * yyxml_str=NULL; // for XML
+// for id attribute generation (by William Candillon)
+int _id = 0; 
+char str[[256]];
+])[
 
   /* The number of symbols on the RHS of the reduced rule.
      Keep to zero when no symbol should be popped.  */
@@ -1410,7 +1634,9 @@ b4_function_define([[yyparse]], [[int]], b4_parse_param)[
       goto yyread_pushed_token;
     }]])[
 
-  yyssp = yyss = yyssa;
+  yyssp = yyss = yyssa;]b4_yaxx([
+  yyxsp = yyxs = yyxsa;
+])[
   yyvsp = yyvs = yyvsa;]b4_locations_if([[
   yylsp = yyls = yylsa;]])[
   yystacksize = YYINITDEPTH;]b4_lac_if([[
@@ -1460,7 +1686,7 @@ b4_locations_if([[  yylsp[0] = ]b4_push_if([b4_pure_if([*])yypushed_loc], [yyllo
            these so that the &'s don't force the real ones into
            memory.  */
         YYSTYPE *yyvs1 = yyvs;
-        yytype_int16 *yyss1 = yyss;]b4_locations_if([
+        yytype_int16 *yyss1 = yyss;]b4_yaxx([ char **yyxs1 = yyxs;])[]b4_locations_if([
         YYLTYPE *yyls1 = yyls;])[
 
         /* Each stack pointer address is followed by the size of the
@@ -1469,9 +1695,9 @@ b4_locations_if([[  yylsp[0] = ]b4_push_if([b4_pure_if([*])yypushed_loc], [yyllo
            be undefined if yyoverflow is a macro.  */
         yyoverflow (YY_("memory exhausted"),
                     &yyss1, yysize * sizeof (*yyssp),
-                    &yyvs1, yysize * sizeof (*yyvsp),]b4_locations_if([
+                    &yyvs1, yysize * sizeof (*yyvsp),]b4_yaxx([&yyxs1, yysize * sizeof (*yyxsp),])[]b4_locations_if([
                     &yyls1, yysize * sizeof (*yylsp),])[
-                    &yystacksize);
+                    &yystacksize);]b4_yaxx([yyxs = yyxs1;])[
 ]b4_locations_if([
         yyls = yyls1;])[
         yyss = yyss1;
@@ -1495,7 +1721,7 @@ b4_locations_if([[  yylsp[0] = ]b4_push_if([b4_pure_if([*])yypushed_loc], [yyllo
         if (! yyptr)
           goto yyexhaustedlab;
         YYSTACK_RELOCATE (yyss_alloc, yyss);
-        YYSTACK_RELOCATE (yyvs_alloc, yyvs);]b4_locations_if([
+        YYSTACK_RELOCATE (yyvs_alloc, yyvs);]b4_yaxx([YYSTACK_RELOCATE (yyxs_alloc, yyxs);])[]b4_locations_if([
         YYSTACK_RELOCATE (yyls_alloc, yyls);])[
 #  undef YYSTACK_RELOCATE
         if (yyss1 != yyssa)
@@ -1505,7 +1731,7 @@ b4_locations_if([[  yylsp[0] = ]b4_push_if([b4_pure_if([*])yypushed_loc], [yyllo
 #endif /* no yyoverflow */
 
       yyssp = yyss + yysize - 1;
-      yyvsp = yyvs + yysize - 1;]b4_locations_if([
+      yyvsp = yyvs + yysize - 1;]b4_yaxx([yyxsp = yyxs + yysize - 1;])[]b4_locations_if([
       yylsp = yyls + yysize - 1;])[
 
       YYDPRINTF ((stderr, "Stack size increased to %lu\n",
@@ -1570,7 +1796,33 @@ yyread_pushed_token:]])[
     }
   else
     {
-      yytoken = YYTRANSLATE (yychar);
+      yytoken = YYTRANSLATE (yychar);]b4_yaxx([
+{ // Yijun Yu: process the terminal
+      yyxml_str = (char *) XML_ALLOC(200);
+      strcpy(yyxml_str, "<yaxx:");
+      strcat(yyxml_str, YYTNAME(yytoken));      
+#if 1 //William Candillon
+      strcat(yyxml_str, " id=\"");
+      sprintf(str, "%x", _id);
+      strcat(yyxml_str, str);
+      strcat(yyxml_str, "\"");
+      _id++;
+#endif
+      strcat(yyxml_str, ">");
+      if (yytoken < YYNTOKENS) {
+	  if (yytext) {
+		  char *tmp;
+		  tmp=(char *)YYSTACK_ALLOC(6*strlen(yytext)+1); 
+		  replace_special_entities(yytext,tmp);
+		  strcat(yyxml_str, tmp);
+		  YYSTACK_FREE(tmp);
+	  }
+      }
+      strcat(yyxml_str, "</yaxx:");
+      strcat(yyxml_str, YYTNAME(yytoken));
+      strcat(yyxml_str, ">\n");
+    }
+])[
       YY_SYMBOL_PRINT ("Next token is", yytoken, &yylval, &yylloc);
     }
 
@@ -1607,6 +1859,10 @@ yyread_pushed_token:]])[
 
   yystate = yyn;
   YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+]b4_yaxx([
+  *++yyxsp = yyxml_str;
+  yyxml_str = 0;
+])[
   *++yyvsp = yylval;
   YY_IGNORE_MAYBE_UNINITIALIZED_END
 ]b4_locations_if([  *++yylsp = yylloc;])[
@@ -1654,6 +1910,53 @@ yyreduce:
     if (yychar_backup != yychar)
       YY_LAC_DISCARD ("yychar change");
   }]], [[
+]b4_yaxx([
+  {
+      int len = 0;
+      int alloc_len=0;
+      int n = 0;
+      int yyi;
+      for (yyi = 0; yyi < yylen; yyi++)
+      {
+          int l;
+          char * yyxml_str = yyxsp[[yyi+1-yylen]];
+          if (yyxml_str==NULL) {
+            l = 0;
+          } else
+            l = strlen(yyxml_str);
+          len += l;
+	  n++;
+      }
+      alloc_len =len+100+2*strlen(YYTNAME(yyr1[[yyn]]));
+      yyxml_str = (char *) XML_ALLOC(alloc_len);
+      strcpy(yyxml_str, "<yaxx:");
+      strcat(yyxml_str, YYTNAME(yyr1[[yyn]]));
+#if 1 //William Candillon
+      strcat(yyxml_str, " id=\"");
+      sprintf(str, "%x", _id);
+      strcat(yyxml_str, str);
+      strcat(yyxml_str, "\"");
+      _id++;
+#endif
+      strcat(yyxml_str, ">\n");
+      for (yyi = 0; yyi < yylen; yyi++)
+      {
+          char * xml_str = yyxsp[[yyi+1-yylen]];
+          if (xml_str) {
+              strcat(yyxml_str, xml_str); 
+              XML_FREE(xml_str);
+              yyxsp[[yyi+1-yylen]] = NULL;
+          } else {
+            fprintf(stderr, "Warning! the %d-th argument is empty", yyi+1);
+          }
+      }
+      strcat(yyxml_str, "</yaxx:");
+      strcat(yyxml_str, YYTNAME(yyr1[[yyn]]));
+      strcat(yyxml_str, ">\n");
+      yyxsp -= n;
+      *++yyxsp = yyxml_str;
+      yyxml_str = NULL;
+    }])[
   switch (yyn)
     {
       ]b4_user_actions[
@@ -1829,6 +2132,10 @@ yyerrlab1:
   YY_LAC_DISCARD ("error recovery");]])[
 
   YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN
+]b4_yaxx([
+  *++yyxsp = yyxml_str;
+  yyxml_str = 0;
+])[
   *++yyvsp = yylval;
   YY_IGNORE_MAYBE_UNINITIALIZED_END
 ]b4_locations_if([[
@@ -1848,7 +2155,7 @@ yyerrlab1:
 /*-------------------------------------.
 | yyacceptlab -- YYACCEPT comes here.  |
 `-------------------------------------*/
-yyacceptlab:
+yyacceptlab:]b4_yaxx([generate_xml_output(--yyxsp,yyxs);])[
   yyresult = 0;
   goto yyreturn;
 

src/AnnotationList.c

@@ -242,7 +242,7 @@ AnnotationList__computePredecessorAnnotations (AnnotationList *self, state *s,
           {
             symbol_number contribution_token =
               InadequacyList__getContributionToken (self->inadequacyNode, ci)
-                ->number;
+                ->content->number;
             if (AnnotationList__isContributionAlways (self, ci))
               {
                 annotation_node->contributions[ci] = NULL;
@@ -553,7 +553,7 @@ AnnotationList__compute_from_inadequacies (
                    does discard annotations in the simplest case of a S/R
                    conflict with no token precedence.  */
                 aver (!bitset_test (shift_tokens, conflicted_token)
-                      || symbols[conflicted_token]->prec);
+                      || symbols[conflicted_token]->content->prec);
                 ++annotation_counts[s->number];
                 if (contribution_count > *max_contributionsp)
                   *max_contributionsp = contribution_count;
@@ -599,7 +599,7 @@ AnnotationList__debug (AnnotationList const *self, size_t nitems, int spaces)
           {
             symbol_number token =
               InadequacyList__getContributionToken (a->inadequacyNode, ci)
-                ->number;
+                ->content->number;
             {
               int j;
               for (j = 0; j < spaces+2; ++j)
@@ -648,7 +648,7 @@ AnnotationList__computeLookaheadFilter (AnnotationList const *self,
             Sbitset biter;
             symbol_number token =
               InadequacyList__getContributionToken (self->inadequacyNode, ci)
-                ->number;
+                ->content->number;
             SBITSET__FOR_EACH (self->contributions[ci], nitems, biter, item)
               bitset_set (lookahead_filter[item], token);
           }
@@ -683,7 +683,8 @@ AnnotationList__stateMakesContribution (AnnotationList const *self,
     return false;
   {
     symbol_number token =
-      InadequacyList__getContributionToken (self->inadequacyNode, ci)->number;
+      InadequacyList__getContributionToken (self->inadequacyNode, ci)
+      ->content->number;
     Sbitset__Index item;
     Sbitset biter;
     SBITSET__FOR_EACH (self->contributions[ci], nitems, biter, item)
@@ -713,7 +714,7 @@ AnnotationList__computeDominantContribution (AnnotationList const *self,
         ContributionIndex ci;
         int actioni;
         ContributionIndex ci_rr_dominator = ContributionIndex__none;
-        int shift_precedence = token->prec;
+        int shift_precedence = token->content->prec;
 
         /* If the token has no precedence set, shift is always chosen.  */
         if (!shift_precedence)
@@ -743,7 +744,7 @@ AnnotationList__computeDominantContribution (AnnotationList const *self,
             if (reduce_precedence
                 && (reduce_precedence < shift_precedence
                     || (reduce_precedence == shift_precedence
-                        && token->assoc == right_assoc)))
+                        && token->content->assoc == right_assoc)))
               continue;
             if (!AnnotationList__stateMakesContribution (self, nitems, ci,
                                                          lookaheads))
@@ -751,7 +752,7 @@ AnnotationList__computeDominantContribution (AnnotationList const *self,
             /* This uneliminated reduction contributes, so see if it can cause
                an error action.  */
             if (reduce_precedence == shift_precedence
-                 && token->assoc == non_assoc)
+                 && token->content->assoc == non_assoc)
               {
                 /* It's not possible to find split-stable domination over
                    shift after a potential %nonassoc.  */

src/conflicts.c

@@ -104,7 +104,7 @@ log_resolution (rule *r, symbol_number token,
         case shift_resolution:
           obstack_printf (&solved_conflicts_obstack,
                           " (%s < %s)",
-                          r->prec->tag,
+                          r->prec->symbol->tag,
                           symbols[token]->tag);
           break;
 
@@ -112,7 +112,7 @@ log_resolution (rule *r, symbol_number token,
           obstack_printf (&solved_conflicts_obstack,
                           " (%s < %s)",
                           symbols[token]->tag,
-                          r->prec->tag);
+                          r->prec->symbol->tag);
           break;
 
         case left_resolution:
@@ -176,7 +176,7 @@ log_resolution (rule *r, symbol_number token,
         case shift_resolution:
           obstack_printf (&solved_conflicts_xml_obstack,
                           "%s &lt; %s",
-                          xml_escape_n (0, r->prec->tag),
+                          xml_escape_n (0, r->prec->symbol->tag),
                           xml_escape_n (1, symbols[token]->tag));
           break;
 
@@ -184,7 +184,7 @@ log_resolution (rule *r, symbol_number token,
           obstack_printf (&solved_conflicts_xml_obstack,
                           "%s &lt; %s",
                           xml_escape_n (0, symbols[token]->tag),
-                          xml_escape_n (1, r->prec->tag));
+                          xml_escape_n (1, r->prec->symbol->tag));
           break;
 
         case left_resolution:
@@ -269,18 +269,18 @@ resolve_sr_conflict (state *s, int ruleno, symbol **errors, int *nerrs)
   for (i = 0; i < ntokens; i++)
     if (bitset_test (lookahead_tokens, i)
         && bitset_test (lookahead_set, i)
-        && symbols[i]->prec)
+        && symbols[i]->content->prec)
       {
         /* Shift-reduce conflict occurs for token number i
            and it has a precedence.
            The precedence of shifting is that of token i.  */
-        if (symbols[i]->prec < redprec)
+        if (symbols[i]->content->prec < redprec)
           {
             register_precedence (redrule->prec->number, i);
             log_resolution (redrule, i, reduce_resolution);
             flush_shift (s, i);
           }
-        else if (symbols[i]->prec > redprec)
+        else if (symbols[i]->content->prec > redprec)
           {
             register_precedence (i, redrule->prec->number);
             log_resolution (redrule, i, shift_resolution);
@@ -294,7 +294,7 @@ resolve_sr_conflict (state *s, int ruleno, symbol **errors, int *nerrs)
              For right associativity, keep only the shift.
              For nonassociativity, keep neither.  */
 
-          switch (symbols[i]->assoc)
+          switch (symbols[i]->content->assoc)
             {
             case undef_assoc:
               abort ();

src/gram.c

@@ -65,19 +65,19 @@ rule_useless_in_parser_p (rule const *r)
 }
 
 void
-rule_lhs_print (rule const *r, symbol const *previous_lhs, FILE *out)
+rule_lhs_print (rule const *r, sym_content const *previous_lhs, FILE *out)
 {
   fprintf (out, "  %3d ", r->number);
   if (previous_lhs != r->lhs)
-    fprintf (out, "%s:", r->lhs->tag);
+    fprintf (out, "%s:", r->lhs->symbol->tag);
   else
-    fprintf (out, "%*s|", (int) strlen (previous_lhs->tag), "");
+    fprintf (out, "%*s|", (int) strlen (previous_lhs->symbol->tag), "");
 }
 
 void
 rule_lhs_print_xml (rule const *r, FILE *out, int level)
 {
-  xml_printf (out, level, "<lhs>%s</lhs>", r->lhs->tag);
+  xml_printf (out, level, "<lhs>%s</lhs>", r->lhs->symbol->tag);
 }
 
 size_t
@@ -158,7 +158,7 @@ grammar_rules_partial_print (FILE *out, const char *title,
 {
   rule_number r;
   bool first = true;
-  symbol *previous_lhs = NULL;
+  sym_content *previous_lhs = NULL;
 
   /* rule # : LHS -> RHS */
   for (r = 0; r < nrules + nuseless_productions; r++)
@@ -209,7 +209,7 @@ grammar_rules_print_xml (FILE *out, int level)
                  rules[r].number, usefulness);
         if (rules[r].precsym)
           fprintf (out, " percent_prec=\"%s\"",
-                   xml_escape (rules[r].precsym->tag));
+                   xml_escape (rules[r].precsym->symbol->tag));
         fputs (">\n", out);
       }
       rule_lhs_print_xml (&rules[r], out, level + 3);
@@ -239,7 +239,7 @@ grammar_dump (FILE *out, const char *title)
     for (i = ntokens; i < nsyms; i++)
       fprintf (out, "%5d  %5d   %5d  %s\n",
                i,
-               symbols[i]->prec, symbols[i]->assoc,
+               symbols[i]->content->prec, symbols[i]->content->assoc,
                symbols[i]->tag);
     fprintf (out, "\n\n");
   }
@@ -280,7 +280,7 @@ grammar_dump (FILE *out, const char *title)
     rule_number r;
     for (r = 0; r < nrules + nuseless_productions; r++)
       {
-        fprintf (out, "%-5d  %s:", r, rules[r].lhs->tag);
+        fprintf (out, "%-5d  %s:", r, rules[r].lhs->symbol->tag);
         rule_rhs_print (&rules[r], out);
         fprintf (out, "\n");
       }
@@ -293,7 +293,10 @@ grammar_rules_useless_report (const char *message)
 {
   rule_number r;
   for (r = 0; r < nrules ; ++r)
-    if (!rules[r].useful)
+    /* Don't complain about rules whose LHS is useless, we already
+       complained about it.  */
+    if (!reduce_nonterminal_useless_in_grammar (rules[r].lhs)
+        && !rules[r].useful)
       complain (&rules[r].location, Wother, "%s", message);
 }
 

src/gram.h

@@ -180,17 +180,17 @@ typedef struct
      except if some rules are useless.  */
   rule_number number;
 
-  symbol *lhs;
+  sym_content *lhs;
   item_number *rhs;
 
   /* This symbol provides both the associativity, and the precedence. */
-  symbol *prec;
+  sym_content *prec;
 
   int dprec;
   int merger;
 
   /* This symbol was attached to the rule via %prec. */
-  symbol *precsym;
+  sym_content *precsym;
 
   location location;
   bool useful;
@@ -220,7 +220,8 @@ bool rule_useless_in_parser_p (rule const *r);
 /* Print this rule's number and lhs on OUT.  If a PREVIOUS_LHS was
    already displayed (by a previous call for another rule), avoid
    useless repetitions.  */
-void rule_lhs_print (rule const *r, symbol const *previous_lhs, FILE *out);
+void rule_lhs_print (rule const *r, sym_content const *previous_lhs,
+                     FILE *out);
 void rule_lhs_print_xml (rule const *r, FILE *out, int level);
 
 /* Return the length of the RHS.  */

src/graphviz.c

@@ -93,7 +93,7 @@ no_reduce_bitset_init (state const *s, bitset *no_reduce_set)
     bitset_set (*no_reduce_set, TRANSITION_SYMBOL (s->transitions, n));
   for (n = 0; n < s->errs->num; ++n)
     if (s->errs->symbols[n])
-      bitset_set (*no_reduce_set, s->errs->symbols[n]->number);
+      bitset_set (*no_reduce_set, s->errs->symbols[n]->content->number);
 }
 
 static void

src/ielr.c

@@ -424,7 +424,7 @@ ielr_item_has_lookahead (state *s, symbol_number lhs, size_t item,
           if (item_number_is_rule_number (ritem[s->items[item] - 2]))
             {
               state **predecessor;
-              aver (lhs != accept->number);
+              aver (lhs != accept->content->number);
               for (predecessor = predecessors[s->number];
                    *predecessor;
                    ++predecessor)
@@ -580,7 +580,7 @@ typedef struct state_list {
 static void
 ielr_compute_goto_follow_set (bitsetv follow_kernel_items,
                               bitsetv always_follows, state_list *s,
-                              symbol *n, bitset follow_set)
+                              sym_content *n, bitset follow_set)
 {
   goto_number n_goto = map_goto (s->lr0Isocore->state->number, n->number);
   bitset_copy (follow_set, always_follows[n_goto]);

src/output.c

@@ -149,7 +149,7 @@ prepare_symbols (void)
   MUSCLE_INSERT_INT ("tokens_number", ntokens);
   MUSCLE_INSERT_INT ("nterms_number", nvars);
   MUSCLE_INSERT_INT ("symbols_number", nsyms);
-  MUSCLE_INSERT_INT ("undef_token_number", undeftoken->number);
+  MUSCLE_INSERT_INT ("undef_token_number", undeftoken->content->number);
   MUSCLE_INSERT_INT ("user_token_number_max", max_user_token_number);
 
   muscle_insert_symbol_number_table ("translate",
@@ -197,7 +197,7 @@ prepare_symbols (void)
     int i;
     int *values = xnmalloc (ntokens, sizeof *values);
     for (i = 0; i < ntokens; ++i)
-      values[i] = symbols[i]->user_token_number;
+      values[i] = symbols[i]->content->user_token_number;
     muscle_insert_int_table ("toknum", values,
                              values[0], 1, ntokens);
     free (values);
@@ -283,9 +283,9 @@ prepare_states (void)
 static int
 symbol_type_name_cmp (const symbol **lhs, const symbol **rhs)
 {
-  int res = uniqstr_cmp ((*lhs)->type_name, (*rhs)->type_name);
+  int res = uniqstr_cmp ((*lhs)->content->type_name, (*rhs)->content->type_name);
   if (!res)
-    res = (*lhs)->number - (*rhs)->number;
+    res = (*lhs)->content->number - (*rhs)->content->number;
   return res;
 }
 
@@ -320,8 +320,9 @@ type_names_output (FILE *out)
       /* The index of the first symbol of the current type-name.  */
       int i0 = i;
       fputs (i ? ",\n[" : "[", out);
-      for (; i < nsyms && syms[i]->type_name == syms[i0]->type_name; ++i)
+      for (; i < nsyms
-        fprintf (out, "%s%d", i != i0 ? ", " : "", syms[i]->number);
+           && syms[i]->content->type_name == syms[i0]->content->type_name; ++i)
+        fprintf (out, "%s%d", i != i0 ? ", " : "", syms[i]->content->number);
       fputs ("]", out);
     }
   fputs ("])\n\n", out);
@@ -428,20 +429,21 @@ prepare_symbol_definitions (void)
       MUSCLE_INSERT_STRING (key, sym->tag);
 
       SET_KEY ("user_number");
-      MUSCLE_INSERT_INT (key, sym->user_token_number);
+      MUSCLE_INSERT_INT (key, sym->content->user_token_number);
 
       SET_KEY ("is_token");
       MUSCLE_INSERT_INT (key,
                          i < ntokens && sym != errtoken && sym != undeftoken);
 
       SET_KEY ("number");
-      MUSCLE_INSERT_INT (key, sym->number);
+      MUSCLE_INSERT_INT (key, sym->content->number);
 
       SET_KEY ("has_type");
-      MUSCLE_INSERT_INT (key, !!sym->type_name);
+      MUSCLE_INSERT_INT (key, !!sym->content->type_name);
 
       SET_KEY ("type");
-      MUSCLE_INSERT_STRING (key, sym->type_name ? sym->type_name : "");
+      MUSCLE_INSERT_STRING (key, sym->content->type_name
+                            ? sym->content->type_name : "");
 
       {
         int j;

src/parse-gram.c

@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 3.0.2.13-975bb-dirty.  */
+/* A Bison parser, made by GNU Bison 3.0.2.29-9a91e.  */
 
 /* Bison implementation for Yacc-like parsers in C
 
@@ -44,7 +44,7 @@
 #define YYBISON 1
 
 /* Bison version.  */
-#define YYBISON_VERSION "3.0.2.13-975bb-dirty"
+#define YYBISON_VERSION "3.0.2.29-9a91e"
 
 /* Skeleton name.  */
 #define YYSKELETON_NAME "yacc.c"
@@ -3118,6 +3118,8 @@ current_lhs (symbol *sym, location loc, named_ref *ref)
 {
   current_lhs_symbol = sym;
   current_lhs_location = loc;
+  if (sym)
+    symbol_location_as_lhs_set (sym, loc);
   /* In order to simplify memory management, named references for lhs
      are always assigned by deep copy into the current symbol_list
      node.  This is because a single named-ref in the grammar may

src/parse-gram.h

@@ -1,4 +1,4 @@
-/* A Bison parser, made by GNU Bison 3.0.2.13-975bb-dirty.  */
+/* A Bison parser, made by GNU Bison 3.0.2.29-9a91e.  */
 
 /* Bison interface for Yacc-like parsers in C
 

src/parse-gram.y

@@ -865,6 +865,8 @@ current_lhs (symbol *sym, location loc, named_ref *ref)
 {
   current_lhs_symbol = sym;
   current_lhs_location = loc;
+  if (sym)
+    symbol_location_as_lhs_set (sym, loc);
   /* In order to simplify memory management, named references for lhs
      are always assigned by deep copy into the current symbol_list
      node.  This is because a single named-ref in the grammar may

src/print-xml.c

@@ -259,7 +259,7 @@ print_reductions (FILE *out, int level, state *s)
     bitset_set (no_reduce_set, TRANSITION_SYMBOL (trans, i));
   for (i = 0; i < s->errs->num; ++i)
     if (s->errs->symbols[i])
-      bitset_set (no_reduce_set, s->errs->symbols[i]->number);
+      bitset_set (no_reduce_set, s->errs->symbols[i]->content->number);
 
   if (default_reduction)
     report = true;
@@ -388,11 +388,11 @@ print_grammar (FILE *out, int level)
   /* Terminals */
   xml_puts (out, level + 1, "<terminals>");
   for (i = 0; i < max_user_token_number + 1; i++)
-    if (token_translations[i] != undeftoken->number)
+    if (token_translations[i] != undeftoken->content->number)
       {
         char const *tag = symbols[token_translations[i]]->tag;
-        int precedence = symbols[token_translations[i]]->prec;
+        int precedence = symbols[token_translations[i]]->content->prec;
-        assoc associativity = symbols[token_translations[i]]->assoc;
+        assoc associativity = symbols[token_translations[i]]->content->assoc;
         xml_indent (out, level + 2);
         fprintf (out,
                  "<terminal symbol-number=\"%d\" token-number=\"%d\""
@@ -417,7 +417,7 @@ print_grammar (FILE *out, int level)
                   "<nonterminal symbol-number=\"%d\" name=\"%s\""
                   " usefulness=\"%s\"/>",
                   i, xml_escape (tag),
-                  reduce_nonterminal_useless_in_grammar (i)
+                  reduce_nonterminal_useless_in_grammar (symbols[i]->content)
                     ? "useless-in-grammar" : "useful");
     }
   xml_puts (out, level + 1, "</nonterminals>");

src/print.c

@@ -72,7 +72,7 @@ print_core (FILE *out, state *s)
   size_t i;
   item_number *sitems = s->items;
   size_t snritems = s->nitems;
-  symbol *previous_lhs = NULL;
+  sym_content *previous_lhs = NULL;
 
   /* Output all the items of a state, not only its kernel.  */
   if (report_flag & report_itemsets)
@@ -226,7 +226,8 @@ print_reduction (FILE *out, size_t width,
   if (!enabled)
     fputc ('[', out);
   if (r->number)
-    fprintf (out, _("reduce using rule %d (%s)"), r->number, r->lhs->tag);
+    fprintf (out, _("reduce using rule %d (%s)"), r->number,
+             r->lhs->symbol->tag);
   else
     fprintf (out, _("accept"));
   if (!enabled)
@@ -260,7 +261,7 @@ print_reductions (FILE *out, state *s)
     bitset_set (no_reduce_set, TRANSITION_SYMBOL (trans, i));
   for (i = 0; i < s->errs->num; ++i)
     if (s->errs->symbols[i])
-      bitset_set (no_reduce_set, s->errs->symbols[i]->number);
+      bitset_set (no_reduce_set, s->errs->symbols[i]->content->number);
 
   /* Compute the width of the lookahead token column.  */
   if (default_reduction)
@@ -412,7 +413,7 @@ print_grammar (FILE *out)
   /* TERMINAL (type #) : rule #s terminal is on RHS */
   fprintf (out, "%s\n\n", _("Terminals, with rules where they appear"));
   for (i = 0; i < max_user_token_number + 1; i++)
-    if (token_translations[i] != undeftoken->number)
+    if (token_translations[i] != undeftoken->content->number)
       {
         const char *tag = symbols[token_translations[i]]->tag;
         rule_number r;

src/print_graph.c

@@ -46,7 +46,7 @@ static void
 print_core (struct obstack *oout, state *s)
 {
   item_number const *sitems = s->items;
-  symbol *previous_lhs = NULL;
+  sym_content *previous_lhs = NULL;
   size_t i;
   size_t snritems = s->nitems;
 
@@ -72,11 +72,12 @@ print_core (struct obstack *oout, state *s)
       r = &rules[item_number_as_rule_number (*sp)];
 
       obstack_printf (oout, "%3d ", r->number);
-      if (previous_lhs && UNIQSTR_EQ (previous_lhs->tag, r->lhs->tag))
+      if (previous_lhs && UNIQSTR_EQ (previous_lhs->symbol->tag,
+                                      r->lhs->symbol->tag))
         obstack_printf (oout, "%*s| ",
-                        (int) strlen (previous_lhs->tag), "");
+                        (int) strlen (previous_lhs->symbol->tag), "");
       else
-        obstack_printf (oout, "%s: ", escape (r->lhs->tag));
+        obstack_printf (oout, "%s: ", escape (r->lhs->symbol->tag));
       previous_lhs = r->lhs;
 
       for (sp = r->rhs; sp < sp1; sp++)

src/reader.c

@@ -240,13 +240,13 @@ grammar_current_rule_begin (symbol *lhs, location loc,
   current_rule = grammar_end;
 
   /* Mark the rule's lhs as a nonterminal if not already so.  */
-  if (lhs->class == unknown_sym)
+  if (lhs->content->class == unknown_sym)
     {
-      lhs->class = nterm_sym;
+      lhs->content->class = nterm_sym;
-      lhs->number = nvars;
+      lhs->content->number = nvars;
       ++nvars;
     }
-  else if (lhs->class == token_sym)
+  else if (lhs->content->class == token_sym)
     complain (&loc, complaint, _("rule given for %s, which is a token"),
               lhs->tag);
 }
@@ -292,15 +292,15 @@ grammar_rule_check (const symbol_list *r)
 
      Don't worry about the default action if $$ is untyped, since $$'s
      value can't be used.  */
-  if (!r->action_props.code && r->content.sym->type_name)
+  if (!r->action_props.code && r->content.sym->content->type_name)
     {
       symbol *first_rhs = r->next->content.sym;
       /* If $$ is being set in default way, report if any type mismatch.  */
       if (first_rhs)
         {
-          char const *lhs_type = r->content.sym->type_name;
+          char const *lhs_type = r->content.sym->content->type_name;
           const char *rhs_type =
-            first_rhs->type_name ? first_rhs->type_name : "";
+            first_rhs->content->type_name ? first_rhs->content->type_name : "";
           if (!UNIQSTR_EQ (lhs_type, rhs_type))
             complain (&r->location, Wother,
                       _("type clash on default action: <%s> != <%s>"),
@@ -350,7 +350,8 @@ grammar_rule_check (const symbol_list *r)
      it for char literals and strings, which are always tokens.  */
   if (r->ruleprec
       && r->ruleprec->tag[0] != '\'' && r->ruleprec->tag[0] != '"'
-      && r->ruleprec->status != declared && !r->ruleprec->prec)
+      && r->ruleprec->content->status != declared
+      && !r->ruleprec->content->prec)
     complain (&r->location, Wother,
               _("token for %%prec is not defined: %s"), r->ruleprec->tag);
 }
@@ -517,8 +518,8 @@ grammar_current_rule_symbol_append (symbol *sym, location loc,
   p = grammar_symbol_append (sym, loc);
   if (name)
     assign_named_ref (p, name);
-  if (sym->status == undeclared || sym->status == used)
+  if (sym->content->status == undeclared || sym->content->status == used)
-    sym->status = needed;
+    sym->content->status = needed;
 }
 
 /* Attach an ACTION to the current rule.  */
@@ -558,11 +559,11 @@ packgram (void)
   for (p = grammar; p; p = p->next)
     {
       symbol *ruleprec = p->ruleprec;
-      record_merge_function_type (p->merger, p->content.sym->type_name,
+      record_merge_function_type (p->merger, p->content.sym->content->type_name,
                                   p->merger_declaration_location);
       rules[ruleno].user_number = ruleno;
       rules[ruleno].number = ruleno;
-      rules[ruleno].lhs = p->content.sym;
+      rules[ruleno].lhs = p->content.sym->content;
       rules[ruleno].rhs = ritem + itemno;
       rules[ruleno].prec = NULL;
       rules[ruleno].dprec = p->dprec;
@@ -604,11 +605,11 @@ packgram (void)
             /* item_number = symbol_number.
                But the former needs to contain more: negative rule numbers. */
             ritem[itemno++] =
-              symbol_number_as_item_number (p->content.sym->number);
+              symbol_number_as_item_number (p->content.sym->content->number);
             /* A rule gets by default the precedence and associativity
                of its last token.  */
-            if (p->content.sym->class == token_sym && default_prec)
+            if (p->content.sym->content->class == token_sym && default_prec)
-              rules[ruleno].prec = p->content.sym;
+              rules[ruleno].prec = p->content.sym->content;
           }
       }
 
@@ -616,8 +617,8 @@ packgram (void)
          the specified symbol's precedence replaces the default.  */
       if (ruleprec)
         {
-          rules[ruleno].precsym = ruleprec;
+          rules[ruleno].precsym = ruleprec->content;
-          rules[ruleno].prec = ruleprec;
+          rules[ruleno].prec = ruleprec->content;
         }
       /* An item ends by the rule number (negated).  */
       ritem[itemno++] = rule_number_as_item_number (ruleno);
@@ -647,19 +648,19 @@ reader (void)
 
   /* Construct the accept symbol. */
   accept = symbol_get ("$accept", empty_location);
-  accept->class = nterm_sym;
+  accept->content->class = nterm_sym;
-  accept->number = nvars++;
+  accept->content->number = nvars++;
 
   /* Construct the error token */
   errtoken = symbol_get ("error", empty_location);
-  errtoken->class = token_sym;
+  errtoken->content->class = token_sym;
-  errtoken->number = ntokens++;
+  errtoken->content->number = ntokens++;
 
   /* Construct a token that represents all undefined literal tokens.
      It is always token number 2.  */
   undeftoken = symbol_get ("$undefined", empty_location);
-  undeftoken->class = token_sym;
+  undeftoken->content->class = token_sym;
-  undeftoken->number = ntokens++;
+  undeftoken->content->number = ntokens++;
 
   gram_in = xfopen (grammar_file, "r");
 
@@ -721,10 +722,10 @@ check_and_convert_grammar (void)
   if (!endtoken)
     {
       endtoken = symbol_get ("$end", empty_location);
-      endtoken->class = token_sym;
+      endtoken->content->class = token_sym;
-      endtoken->number = 0;
+      endtoken->content->number = 0;
       /* Value specified by POSIX.  */
-      endtoken->user_token_number = 0;
+      endtoken->content->user_token_number = 0;
     }
 
   /* Report any undefined symbols and consider them nonterminals.  */

src/reduce.c

@@ -39,7 +39,7 @@
 #include "reduce.h"
 #include "symtab.h"
 
-/* Set of all nonterminals which are not useless.  */
+/* Set of all nonterminals whose language is not empty.  */
 static bitset N;
 
 /* Set of all rules which have no useless nonterminals in their RHS.  */
@@ -52,11 +52,18 @@ static bitset V;
    'useless', but no warning should be issued).  */
 static bitset V1;
 
-static rule_number nuseful_productions;
+static unsigned nuseful_productions;
-rule_number nuseless_productions;
+unsigned nuseless_productions;
-static int nuseful_nonterminals;
+static unsigned nuseful_nonterminals;
-symbol_number nuseless_nonterminals;
+unsigned nuseless_nonterminals;
 
+#define bitset_swap(Lhs, Rhs)                   \
+  do {                                          \
+    bitset lhs__ = Lhs;                         \
+    Lhs = Rhs;                                  \
+    Rhs = lhs__;                                \
+  } while (0)
+
 /*-------------------------------------------------------------------.
 | Another way to do this would be with a set for each production and |
 | then do subset tests against N0, but even for the C grammar the    |
@@ -71,7 +78,7 @@ useful_production (rule_number r, bitset N0)
   /* A production is useful if all of the nonterminals in its appear
      in the set of useful nonterminals.  */
 
-  for (rhsp = rules[r].rhs; *rhsp >= 0; ++rhsp)
+  for (rhsp = rules[r].rhs; 0 <= *rhsp; ++rhsp)
     if (ISVAR (*rhsp) && !bitset_test (N0, *rhsp - ntokens))
       return false;
   return true;
@@ -85,14 +92,10 @@ useful_production (rule_number r, bitset N0)
 static void
 useless_nonterminals (void)
 {
-  bitset Np, Ns;
-  rule_number r;
-
   /* N is set as built.  Np is set being built this iteration. P is
      set of all productions which have a RHS all in N.  */
 
-  Np = bitset_create (nvars, BITSET_FIXED);
+  bitset Np = bitset_create (nvars, BITSET_FIXED);
-
 
   /* The set being computed is a set of nonterminals which can derive
      the empty string or strings consisting of all terminals. At each
@@ -112,8 +115,9 @@ useless_nonterminals (void)
 
   while (1)
     {
+      rule_number r;
       bitset_copy (Np, N);
-      for (r = 0; r < nrules; r++)
+      for (r = 0; r < nrules; ++r)
         if (!bitset_test (P, r)
             && useful_production (r, N))
           {
@@ -122,9 +126,7 @@ useless_nonterminals (void)
           }
       if (bitset_equal_p (N, Np))
         break;
-      Ns = Np;
+      bitset_swap (N, Np);
-      Np = N;
-      N = Ns;
     }
   bitset_free (N);
   N = Np;
@@ -134,8 +136,6 @@ useless_nonterminals (void)
 static void
 inaccessable_symbols (void)
 {
-  bitset Vp, Vs, Pp;
-
   /* Find out which productions are reachable and which symbols are
      used.  Starting with an empty set of productions and a set of
      symbols which only has the start symbol in it, iterate over all
@@ -159,46 +159,43 @@ inaccessable_symbols (void)
      terminals are printed (if running in verbose mode) so that the
      user can know.  */
 
-  Vp = bitset_create (nsyms, BITSET_FIXED);
+  bitset Vp = bitset_create (nsyms, BITSET_FIXED);
-  Pp = bitset_create (nrules, BITSET_FIXED);
+  bitset Pp = bitset_create (nrules, BITSET_FIXED);
 
   /* If the start symbol isn't useful, then nothing will be useful. */
-  if (bitset_test (N, accept->number - ntokens))
+  if (bitset_test (N, accept->content->number - ntokens))
     {
-      bitset_set (V, accept->number);
+      bitset_set (V, accept->content->number);
 
       while (1)
         {
           rule_number r;
           bitset_copy (Vp, V);
-          for (r = 0; r < nrules; r++)
+          for (r = 0; r < nrules; ++r)
-            {
+            if (!bitset_test (Pp, r)
-              if (!bitset_test (Pp, r)
+                && bitset_test (P, r)
-                  && bitset_test (P, r)
+                && bitset_test (V, rules[r].lhs->number))
-                  && bitset_test (V, rules[r].lhs->number))
+              {
-                {
+                item_number *rhsp;
-                  item_number *rhsp;
+                for (rhsp = rules[r].rhs; 0 <= *rhsp; ++rhsp)
-                  for (rhsp = rules[r].rhs; *rhsp >= 0; rhsp++)
+                  if (ISTOKEN (*rhsp) || bitset_test (N, *rhsp - ntokens))
-                    if (ISTOKEN (*rhsp) || bitset_test (N, *rhsp - ntokens))
+                    bitset_set (Vp, *rhsp);
-                      bitset_set (Vp, *rhsp);
+                bitset_set (Pp, r);
-                  bitset_set (Pp, r);
+              }
-                }
-            }
           if (bitset_equal_p (V, Vp))
             break;
-          Vs = Vp;
+          bitset_swap (V, Vp);
-          Vp = V;
-          V = Vs;
         }
     }
 
   bitset_free (V);
   V = Vp;
 
-  /* Tokens 0, 1, and 2 are internal to Bison.  Consider them useful. */
+  /* These tokens (numbered 0, 1, and 2) are internal to Bison.
-  bitset_set (V, endtoken->number);             /* end-of-input token */
+     Consider them useful. */
-  bitset_set (V, errtoken->number);             /* error token */
+  bitset_set (V, endtoken->content->number);   /* end-of-input token */
-  bitset_set (V, undeftoken->number);           /* some undefined token */
+  bitset_set (V, errtoken->content->number);   /* error token */
+  bitset_set (V, undeftoken->content->number); /* some undefined token */
 
   bitset_free (P);
   P = Pp;
@@ -209,9 +206,8 @@ inaccessable_symbols (void)
   nuseful_nonterminals = 0;
   {
     symbol_number i;
-    for (i = ntokens; i < nsyms; i++)
+    for (i = ntokens; i < nsyms; ++i)
-      if (bitset_test (V, i))
+      nuseful_nonterminals += bitset_test (V, i);
-        nuseful_nonterminals++;
   }
   nuseless_nonterminals = nvars - nuseful_nonterminals;
 
@@ -236,7 +232,7 @@ reduce_grammar_tables (void)
   /* Report and flag useless productions.  */
   {
     rule_number r;
-    for (r = 0; r < nrules; r++)
+    for (r = 0; r < nrules; ++r)
       rules[r].useful = bitset_test (P, r);
     grammar_rules_useless_report (_("rule useless in grammar"));
   }
@@ -257,8 +253,8 @@ reduce_grammar_tables (void)
     for (r = 0; r < nrules; ++r)
       {
         item_number *rhsp = rules[r].rhs;
-        for (/* Nothing. */; *rhsp >= 0; ++rhsp)
+        for (/* Nothing. */; 0 <= *rhsp; ++rhsp)
-          /* Nothing. */;
+          continue;
         *rhsp = rule_number_as_item_number (r);
         rules[r].number = r;
       }
@@ -289,31 +285,33 @@ nonterminals_reduce (void)
      afterwards.  Kept for later report.  */
 
   symbol_number *nontermmap = xnmalloc (nvars, sizeof *nontermmap);
-  symbol_number n = ntokens;
+  {
-  symbol_number i;
+    symbol_number n = ntokens;
-  for (i = ntokens; i < nsyms; i++)
+    symbol_number i;
-    if (bitset_test (V, i))
+    for (i = ntokens; i < nsyms; ++i)
-      nontermmap[i - ntokens] = n++;
+      if (bitset_test (V, i))
-  for (i = ntokens; i < nsyms; i++)
-    if (!bitset_test (V, i))
-      {
         nontermmap[i - ntokens] = n++;
-        if (symbols[i]->status != used)
+    for (i = ntokens; i < nsyms; ++i)
-          complain (&symbols[i]->location, Wother,
+      if (!bitset_test (V, i))
-                    _("nonterminal useless in grammar: %s"),
+        {
-                    symbols[i]->tag);
+          nontermmap[i - ntokens] = n++;
-      }
+          if (symbols[i]->content->status != used)
+            complain (&symbols[i]->location, Wother,
+                      _("nonterminal useless in grammar: %s"),
+                      symbols[i]->tag);
+        }
+  }
 
 
   /* Shuffle elements of tables indexed by symbol number.  */
   {
     symbol **symbols_sorted = xnmalloc (nvars, sizeof *symbols_sorted);
-
+    symbol_number i;
-    for (i = ntokens; i < nsyms; i++)
+    for (i = ntokens; i < nsyms; ++i)
-      symbols[i]->number = nontermmap[i - ntokens];
+      symbols[i]->content->number = nontermmap[i - ntokens];
-    for (i = ntokens; i < nsyms; i++)
+    for (i = ntokens; i < nsyms; ++i)
       symbols_sorted[nontermmap[i - ntokens] - ntokens] = symbols[i];
-    for (i = ntokens; i < nsyms; i++)
+    for (i = ntokens; i < nsyms; ++i)
       symbols[i] = symbols_sorted[i - ntokens];
     free (symbols_sorted);
   }
@@ -323,12 +321,12 @@ nonterminals_reduce (void)
     for (r = 0; r < nrules; ++r)
       {
         item_number *rhsp;
-        for (rhsp = rules[r].rhs; *rhsp >= 0; ++rhsp)
+        for (rhsp = rules[r].rhs; 0 <= *rhsp; ++rhsp)
           if (ISVAR (*rhsp))
             *rhsp =  symbol_number_as_item_number (nontermmap[*rhsp
                                                               - ntokens]);
       }
-    accept->number = nontermmap[accept->number - ntokens];
+    accept->content->number = nontermmap[accept->content->number - ntokens];
   }
 
   nsyms -= nuseless_nonterminals;
@@ -345,7 +343,7 @@ nonterminals_reduce (void)
 void
 reduce_output (FILE *out)
 {
-  if (nuseless_nonterminals > 0)
+  if (nuseless_nonterminals)
     {
       int i;
       fprintf (out, "%s\n\n", _("Nonterminals useless in grammar"));
@@ -357,7 +355,7 @@ reduce_output (FILE *out)
   {
     bool b = false;
     int i;
-    for (i = 0; i < ntokens; i++)
+    for (i = 0; i < ntokens; ++i)
       if (reduce_token_unused_in_grammar (i))
         {
           if (!b)
@@ -369,7 +367,7 @@ reduce_output (FILE *out)
       fputs ("\n\n", out);
   }
 
-  if (nuseless_productions > 0)
+  if (nuseless_productions)
     grammar_rules_partial_print (out, _("Rules useless in grammar"),
                                  rule_useless_in_grammar_p);
 }
@@ -382,12 +380,12 @@ reduce_output (FILE *out)
 static void
 reduce_print (void)
 {
-  if (nuseless_nonterminals > 0)
+  if (nuseless_nonterminals)
     complain (NULL, Wother, ngettext ("%d nonterminal useless in grammar",
                                       "%d nonterminals useless in grammar",
                                       nuseless_nonterminals),
               nuseless_nonterminals);
-  if (nuseless_productions > 0)
+  if (nuseless_productions)
     complain (NULL, Wother, ngettext ("%d rule useless in grammar",
                                       "%d rules useless in grammar",
                                       nuseless_productions),
@@ -397,8 +395,6 @@ reduce_print (void)
 void
 reduce_grammar (void)
 {
-  bool reduced;
-
   /* Allocate the global sets used to compute the reduced grammar */
 
   N = bitset_create (nvars, BITSET_FIXED);
@@ -409,13 +405,13 @@ reduce_grammar (void)
   useless_nonterminals ();
   inaccessable_symbols ();
 
-  reduced = (nuseless_nonterminals + nuseless_productions > 0);
+  /* Did we reduce something? */
-  if (!reduced)
+  if (!nuseless_nonterminals && !nuseless_productions)
     return;
 
   reduce_print ();
 
-  if (!bitset_test (N, accept->number - ntokens))
+  if (!bitset_test (N, accept->content->number - ntokens))
     complain (&startsymbol_location, fatal,
               _("start symbol %s does not derive any sentence"),
               startsymbol->tag);
@@ -423,9 +419,9 @@ reduce_grammar (void)
   /* First reduce the nonterminals, as they renumber themselves in the
      whole grammar.  If you change the order, nonterms would be
      renumbered only in the reduced grammar.  */
-  if (nuseless_nonterminals > 0)
+  if (nuseless_nonterminals)
     nonterminals_reduce ();
-  if (nuseless_productions > 0)
+  if (nuseless_productions)
     reduce_grammar_tables ();
 
   if (trace_flag & trace_grammar)
@@ -446,10 +442,11 @@ reduce_token_unused_in_grammar (symbol_number i)
 }
 
 bool
-reduce_nonterminal_useless_in_grammar (symbol_number i)
+reduce_nonterminal_useless_in_grammar (const sym_content *sym)
 {
-  aver (ntokens <= i && i < nsyms + nuseless_nonterminals);
+  symbol_number n = sym->number;
-  return nsyms <= i;
+  aver (ntokens <= n && n < nsyms + nuseless_nonterminals);
+  return nsyms <= n;
 }
 
 /*-----------------------------------------------------------.

src/reduce.h

@@ -24,9 +24,14 @@
 void reduce_grammar (void);
 void reduce_output (FILE *out);
 bool reduce_token_unused_in_grammar (symbol_number i);
-bool reduce_nonterminal_useless_in_grammar (symbol_number i);
+
+/** Whether symbol \a i is useless in the grammar.
+ * \pre  reduce_grammar was called before.
+ */
+bool reduce_nonterminal_useless_in_grammar (const sym_content *sym);
+
 void reduce_free (void);
 
-extern symbol_number nuseless_nonterminals;
+extern unsigned nuseless_nonterminals;
-extern rule_number nuseless_productions;
+extern unsigned nuseless_productions;
 #endif /* !REDUCE_H_ */

src/state.h

@@ -135,7 +135,7 @@ typedef struct
 /* Is the TRANSITIONS->states[Num] labelled by the error token?  */
 
 # define TRANSITION_IS_ERROR(Transitions, Num) \
-  (TRANSITION_SYMBOL (Transitions, Num) == errtoken->number)
+  (TRANSITION_SYMBOL (Transitions, Num) == errtoken->content->number)
 
 /* When resolving a SR conflicts, if the reduction wins, the shift is
    disabled.  */

src/symlist.c

@@ -192,7 +192,7 @@ symbol_list_n_get (symbol_list *l, int n)
 uniqstr
 symbol_list_n_type_name_get (symbol_list *l, int n)
 {
-  return symbol_list_n_get (l, n)->content.sym->type_name;
+  return symbol_list_n_get (l, n)->content.sym->content->type_name;
 }
 
 bool
@@ -210,8 +210,8 @@ symbol_list_code_props_set (symbol_list *node, code_props_type kind,
     {
     case SYMLIST_SYMBOL:
       symbol_code_props_set (node->content.sym, kind, cprops);
-      if (node->content.sym->status == undeclared)
+      if (node->content.sym->content->status == undeclared)
-        node->content.sym->status = used;
+        node->content.sym->content->status = used;
       break;
     case SYMLIST_TYPE:
       semantic_type_code_props_set

src/symtab.c

@@ -58,6 +58,35 @@ static symgraph **prec_nodes;
 
 bool *used_assoc = NULL;
 
+/*--------------------------.
+| Create a new sym_content. |
+`--------------------------*/
+
+static sym_content *
+sym_content_new (symbol *s)
+{
+  sym_content *res = xmalloc (sizeof *res);
+
+  res->symbol = s;
+
+  res->type_name = NULL;
+  {
+    int i;
+    for (i = 0; i < CODE_PROPS_SIZE; ++i)
+      code_props_none_init (&res->props[i]);
+  }
+
+  res->number = NUMBER_UNDEFINED;
+  res->prec = 0;
+  res->assoc = undef_assoc;
+  res->user_token_number = USER_NUMBER_UNDEFINED;
+
+  res->class = unknown_sym;
+  res->status = undeclared;
+
+  return res;
+}
+
 /*---------------------------------.
 | Create a new symbol, named TAG.  |
 `---------------------------------*/
@@ -76,22 +105,10 @@ symbol_new (uniqstr tag, location loc)
 
   res->tag = tag;
   res->location = loc;
-
+  res->location_of_lhs = false;
-  res->type_name = NULL;
-  {
-    int i;
-    for (i = 0; i < CODE_PROPS_SIZE; ++i)
-      code_props_none_init (&res->props[i]);
-  }
-
-  res->number = NUMBER_UNDEFINED;
-  res->prec = 0;
-  res->assoc = undef_assoc;
-  res->user_token_number = USER_NUMBER_UNDEFINED;
-
   res->alias = NULL;
-  res->class = unknown_sym;
+  res->content = sym_content_new (res);
-  res->status = undeclared;
+  res->is_alias = false;
 
   if (nsyms == SYMBOL_NUMBER_MAXIMUM)
     complain (NULL, fatal, _("too many symbols in input grammar (limit is %d)"),
@@ -100,6 +117,31 @@ symbol_new (uniqstr tag, location loc)
   return res;
 }
 
+/*--------------------.
+| Free a sym_content. |
+`--------------------*/
+
+static void
+sym_content_free (sym_content *sym)
+{
+  free (sym);
+}
+
+
+/*---------------------------------------------------------.
+| Free a symbol and its associated content if appropriate. |
+`---------------------------------------------------------*/
+
+static void
+symbol_free (void *ptr)
+{
+  symbol *sym = (symbol *)ptr;
+  if (!sym->is_alias)
+    sym_content_free (sym->content);
+  free (sym);
+
+}
+
 /* If needed, swap first and second so that first has the earliest
    location (according to location_cmp).
 
@@ -148,6 +190,7 @@ code_props_type_string (code_props_type kind)
   abort ();
 }
 
+
 /*----------------------------------------.
 | Create a new semantic type, named TAG.  |
 `----------------------------------------*/
@@ -176,12 +219,12 @@ semantic_type_new (uniqstr tag, const location *loc)
 `-----------------*/
 
 #define SYMBOL_ATTR_PRINT(Attr)                         \
-  if (s->Attr)                                          \
+  if (s->content->Attr)                                 \
-    fprintf (f, " %s { %s }", #Attr, s->Attr)
+    fprintf (f, " %s { %s }", #Attr, s->content->Attr)
 
 #define SYMBOL_CODE_PRINT(Attr)                                         \
-  if (s->props[Attr].code)                                              \
+  if (s->content->props[Attr].code)                                     \
-    fprintf (f, " %s { %s }", #Attr, s->props[Attr].code)
+    fprintf (f, " %s { %s }", #Attr, s->content->props[Attr].code)
 
 void
 symbol_print (symbol const *s, FILE *f)
@@ -228,7 +271,6 @@ is_identifier (uniqstr s)
 uniqstr
 symbol_id_get (symbol const *sym)
 {
-  aver (sym->user_token_number != USER_NUMBER_HAS_STRING_ALIAS);
   if (sym->alias)
     sym = sym->alias;
   return is_identifier (sym->tag) ? sym->tag : 0;
@@ -267,6 +309,13 @@ semantic_type_redeclaration (semantic_type *s, const char *what, location first,
 }
 
 
+void
+symbol_location_as_lhs_set (symbol *sym, location loc)
+{
+  if (!sym->location_of_lhs)
+    sym->location = loc;
+}
+
 
 /*-----------------------------------------------------------------.
 | Set the TYPE_NAME associated with SYM.  Does nothing if passed 0 |
@@ -278,13 +327,13 @@ symbol_type_set (symbol *sym, uniqstr type_name, location loc)
 {
   if (type_name)
     {
-      if (sym->type_name)
+      if (sym->content->type_name)
-        symbol_redeclaration (sym, "%type", sym->type_location, loc);
+        symbol_redeclaration (sym, "%type", sym->content->type_location, loc);
       else
         {
           uniqstr_assert (type_name);
-          sym->type_name = type_name;
+          sym->content->type_name = type_name;
-          sym->type_location = loc;
+          sym->content->type_location = loc;
         }
     }
 }
@@ -297,12 +346,12 @@ void
 symbol_code_props_set (symbol *sym, code_props_type kind,
                        code_props const *code)
 {
-  if (sym->props[kind].code)
+  if (sym->content->props[kind].code)
     symbol_redeclaration (sym, code_props_type_string (kind),
-                          sym->props[kind].location,
+                          sym->content->props[kind].location,
                           code->location);
   else
-    sym->props[kind] = *code;
+    sym->content->props[kind] = *code;
 }
 
 /*-----------------------------------------------------.
@@ -330,14 +379,14 @@ code_props *
 symbol_code_props_get (symbol *sym, code_props_type kind)
 {
   /* Per-symbol code props.  */
-  if (sym->props[kind].code)
+  if (sym->content->props[kind].code)
-    return &sym->props[kind];
+    return &sym->content->props[kind];
 
   /* Per-type code props.  */
-  if (sym->type_name)
+  if (sym->content->type_name)
     {
       code_props *code =
-        &semantic_type_get (sym->type_name, NULL)->props[kind];
+        &semantic_type_get (sym->content->type_name, NULL)->props[kind];
       if (code->code)
         return code;
     }
@@ -345,8 +394,8 @@ symbol_code_props_get (symbol *sym, code_props_type kind)
   /* Apply default code props's only to user-defined symbols.  */
   if (sym->tag[0] != '$' && sym != errtoken)
     {
-      code_props *code =
+      code_props *code = &semantic_type_get (sym->content->type_name ? "*" : "",
-        &semantic_type_get (sym->type_name ? "*" : "", NULL)->props[kind];
+                                             NULL)->props[kind];
       if (code->code)
         return code;
     }
@@ -361,16 +410,17 @@ symbol_code_props_get (symbol *sym, code_props_type kind)
 void
 symbol_precedence_set (symbol *sym, int prec, assoc a, location loc)
 {
+  sym_content *s = sym->content;
   if (a != undef_assoc)
     {
-      if (sym->prec)
+      if (s->prec)
-        symbol_redeclaration (sym, assoc_to_string (a), sym->prec_location,
+        symbol_redeclaration (sym, assoc_to_string (a),
-                              loc);
+                              s->prec_location, loc);
       else
         {
-          sym->prec = prec;
+          s->prec = prec;
-          sym->assoc = a;
+          s->assoc = a;
-          sym->prec_location = loc;
+          s->prec_location = loc;
         }
     }
 
@@ -387,26 +437,26 @@ void
 symbol_class_set (symbol *sym, symbol_class class, location loc, bool declaring)
 {
   bool warned = false;
-  if (sym->class != unknown_sym && sym->class != class)
+  if (sym->content->class != unknown_sym && sym->content->class != class)
     {
       complain (&loc, complaint, _("symbol %s redefined"), sym->tag);
       /* Don't report both "redefined" and "redeclared".  */
       warned = true;
     }
 
-  if (class == nterm_sym && sym->class != nterm_sym)
+  if (class == nterm_sym && sym->content->class != nterm_sym)
-    sym->number = nvars++;
+    sym->content->number = nvars++;
-  else if (class == token_sym && sym->number == NUMBER_UNDEFINED)
+  else if (class == token_sym && sym->content->number == NUMBER_UNDEFINED)
-    sym->number = ntokens++;
+    sym->content->number = ntokens++;
 
-  sym->class = class;
+  sym->content->class = class;
 
   if (declaring)
     {
-      if (sym->status == declared && !warned)
+      if (sym->content->status == declared && !warned)
         complain (&loc, Wother, _("symbol %s redeclared"), sym->tag);
       else
-        sym->status = declared;
+        sym->content->status = declared;
     }
 }
 
@@ -420,10 +470,7 @@ symbol_user_token_number_set (symbol *sym, int user_token_number, location loc)
 {
   int *user_token_numberp;
 
-  if (sym->user_token_number != USER_NUMBER_HAS_STRING_ALIAS)
+  user_token_numberp = &sym->content->user_token_number;
-    user_token_numberp = &sym->user_token_number;
-  else
-    user_token_numberp = &sym->alias->user_token_number;
   if (*user_token_numberp != USER_NUMBER_UNDEFINED
       && *user_token_numberp != user_token_number)
     complain (&loc, complaint, _("redefining user token number of %s"),
@@ -433,12 +480,12 @@ symbol_user_token_number_set (symbol *sym, int user_token_number, location loc)
   /* User defined $end token? */
   if (user_token_number == 0)
     {
-      endtoken = sym;
+      endtoken = sym->content->symbol;
       /* It is always mapped to 0, so it was already counted in
          NTOKENS.  */
-      if (endtoken->number != NUMBER_UNDEFINED)
+      if (endtoken->content->number != NUMBER_UNDEFINED)
         --ntokens;
-      endtoken->number = 0;
+      endtoken->content->number = 0;
     }
 }
 
@@ -451,16 +498,17 @@ symbol_user_token_number_set (symbol *sym, int user_token_number, location loc)
 static inline bool
 symbol_check_defined (symbol *sym)
 {
-  if (sym->class == unknown_sym)
+  sym_content *s = sym->content;
+  if (s->class == unknown_sym)
     {
-      assert (sym->status != declared);
+      assert (s->status != declared);
       complain (&sym->location,
-                sym->status == needed ? complaint : Wother,
+                s->status == needed ? complaint : Wother,
                 _("symbol %s is used, but is not defined as a token"
                   " and has no rules"),
                   sym->tag);
-      sym->class = nterm_sym;
+      s->class = nterm_sym;
-      sym->number = nvars++;
+      s->number = nvars++;
     }
 
   {
@@ -471,9 +519,9 @@ symbol_check_defined (symbol *sym)
 
   /* Set the semantic type status associated to the current symbol to
      'declared' so that we could check semantic types unnecessary uses. */
-  if (sym->type_name)
+  if (s->type_name)
     {
-      semantic_type *sem_type = semantic_type_get (sym->type_name, NULL);
+      semantic_type *sem_type = semantic_type_get (s->type_name, NULL);
       if (sem_type)
         sem_type->status = declared;
     }
@@ -519,6 +567,45 @@ semantic_type_check_defined_processor (void *sem_type,
 }
 
 
+/*-------------------------------------------------------------------.
+| Merge the properties (precedence, associativity, etc.) of SYM, and |
+| its string-named alias STR; check consistency.                     |
+`-------------------------------------------------------------------*/
+
+static void
+symbol_merge_properties (symbol *sym, symbol *str)
+{
+  if (str->content->type_name != sym->content->type_name)
+    {
+      if (str->content->type_name)
+        symbol_type_set (sym,
+                         str->content->type_name, str->content->type_location);
+      else
+        symbol_type_set (str,
+                         sym->content->type_name, sym->content->type_location);
+    }
+
+
+  {
+    int i;
+    for (i = 0; i < CODE_PROPS_SIZE; ++i)
+      if (str->content->props[i].code)
+        symbol_code_props_set (sym, i, &str->content->props[i]);
+      else if (sym->content->props[i].code)
+        symbol_code_props_set (str, i, &sym->content->props[i]);
+  }
+
+  if (sym->content->prec || str->content->prec)
+    {
+      if (str->content->prec)
+        symbol_precedence_set (sym, str->content->prec, str->content->assoc,
+                               str->content->prec_location);
+      else
+        symbol_precedence_set (str, sym->content->prec, sym->content->assoc,
+                               sym->content->prec_location);
+    }
+}
+
 void
 symbol_make_alias (symbol *sym, symbol *str, location loc)
 {
@@ -530,71 +617,17 @@ symbol_make_alias (symbol *sym, symbol *str, location loc)
               _("symbol %s given more than one literal string"), sym->tag);
   else
     {
-      str->class = token_sym;
+      symbol_merge_properties (sym, str);
-      str->user_token_number = sym->user_token_number;
+      sym_content_free (str->content);
-      sym->user_token_number = USER_NUMBER_HAS_STRING_ALIAS;
+      str->content = sym->content;
+      str->content->symbol = str;
+      str->is_alias = true;
       str->alias = sym;
       sym->alias = str;
-      str->number = sym->number;
-      symbol_type_set (str, sym->type_name, loc);
     }
 }
 
 
-/*---------------------------------------------------------.
-| Check that THIS, and its alias, have same precedence and |
-| associativity.                                           |
-`---------------------------------------------------------*/
-
-static inline void
-symbol_check_alias_consistency (symbol *this)
-{
-  symbol *sym = this;
-  symbol *str = this->alias;
-
-  /* Check only the symbol in the symbol-string pair.  */
-  if (!(this->alias
-        && this->user_token_number == USER_NUMBER_HAS_STRING_ALIAS))
-    return;
-
-  if (str->type_name != sym->type_name)
-    {
-      if (str->type_name)
-        symbol_type_set (sym, str->type_name, str->type_location);
-      else
-        symbol_type_set (str, sym->type_name, sym->type_location);
-    }
-
-
-  {
-    int i;
-    for (i = 0; i < CODE_PROPS_SIZE; ++i)
-      if (str->props[i].code)
-        symbol_code_props_set (sym, i, &str->props[i]);
-      else if (sym->props[i].code)
-        symbol_code_props_set (str, i, &sym->props[i]);
-  }
-
-  if (sym->prec || str->prec)
-    {
-      if (str->prec)
-        symbol_precedence_set (sym, str->prec, str->assoc,
-                               str->prec_location);
-      else
-        symbol_precedence_set (str, sym->prec, sym->assoc,
-                               sym->prec_location);
-    }
-}
-
-static bool
-symbol_check_alias_consistency_processor (void *this,
-                                          void *null ATTRIBUTE_UNUSED)
-{
-  symbol_check_alias_consistency (this);
-  return true;
-}
-
-
 /*-------------------------------------------------------------------.
 | Assign a symbol number, and write the definition of the token name |
 | into FDEFINES.  Put in SYMBOLS.                                    |
@@ -603,13 +636,11 @@ symbol_check_alias_consistency_processor (void *this,
 static inline bool
 symbol_pack (symbol *this)
 {
-  aver (this->number != NUMBER_UNDEFINED);
+  aver (this->content->number != NUMBER_UNDEFINED);
-  if (this->class == nterm_sym)
+  if (this->content->class == nterm_sym)
-    this->number += ntokens;
+    this->content->number += ntokens;
-  else if (this->user_token_number == USER_NUMBER_HAS_STRING_ALIAS)
-    return true;
 
-  symbols[this->number] = this;
+  symbols[this->content->number] = this->content->symbol;
   return true;
 }
 
@@ -619,7 +650,6 @@ symbol_pack_processor (void *this, void *null ATTRIBUTE_UNUSED)
   return symbol_pack (this);
 }
 
-
 static void
 user_token_number_redeclaration (int num, symbol *first, symbol *second)
 {
@@ -642,17 +672,18 @@ static inline bool
 symbol_translation (symbol *this)
 {
   /* Non-terminal? */
-  if (this->class == token_sym
+  if (this->content->class == token_sym
-      && this->user_token_number != USER_NUMBER_HAS_STRING_ALIAS)
+      && !this->is_alias)
     {
-      /* A token which translation has already been set? */
+      /* A token which translation has already been set?*/
-      if (token_translations[this->user_token_number] != undeftoken->number)
+      if (token_translations[this->content->user_token_number]
+          != undeftoken->content->number)
         user_token_number_redeclaration
-          (this->user_token_number,
+          (this->content->user_token_number,
-           symbols[token_translations[this->user_token_number]],
+           symbols[token_translations[this->content->user_token_number]], this);
-           this);
       else
-        token_translations[this->user_token_number] = this->number;
+        token_translations[this->content->user_token_number]
+          = this->content->number;
     }
 
   return true;
@@ -738,7 +769,7 @@ symbols_new (void)
                                   NULL,
                                   hash_symbol_hasher,
                                   hash_symbol_comparator,
-                                  free);
+                                  symbol_free);
   semantic_type_table = hash_initialize (HT_INITIAL_CAPACITY,
                                          NULL,
                                          hash_semantic_type_hasher,
@@ -838,8 +869,8 @@ dummy_symbol_get (location loc)
 
   sprintf (buf, "$@%d", ++dummy_count);
   sym = symbol_get (buf, loc);
-  sym->class = nterm_sym;
+  sym->content->class = nterm_sym;
-  sym->number = nvars++;
+  sym->content->number = nvars++;
   return sym;
 }
 
@@ -929,7 +960,7 @@ symbols_token_translations_init (void)
   max_user_token_number = 0;
   for (i = 0; i < ntokens; ++i)
     {
-      symbol *this = symbols[i];
+      sym_content *this = symbols[i]->content;
       if (this->user_token_number != USER_NUMBER_UNDEFINED)
         {
           if (this->user_token_number > max_user_token_number)
@@ -941,8 +972,8 @@ symbols_token_translations_init (void)
 
   /* If 256 is not used, assign it to error, to follow POSIX.  */
   if (num_256_available_p
-      && errtoken->user_token_number == USER_NUMBER_UNDEFINED)
+      && errtoken->content->user_token_number == USER_NUMBER_UNDEFINED)
-    errtoken->user_token_number = 256;
+    errtoken->content->user_token_number = 256;
 
   /* Set the missing user numbers. */
   if (max_user_token_number < 256)
@@ -950,7 +981,7 @@ symbols_token_translations_init (void)
 
   for (i = 0; i < ntokens; ++i)
     {
-      symbol *this = symbols[i];
+      sym_content *this = symbols[i]->content;
       if (this->user_token_number == USER_NUMBER_UNDEFINED)
         this->user_token_number = ++max_user_token_number;
       if (this->user_token_number > max_user_token_number)
@@ -963,7 +994,7 @@ symbols_token_translations_init (void)
   /* Initialize all entries for literal tokens to the internal token
      number for $undefined, which represents all invalid inputs.  */
   for (i = 0; i < max_user_token_number + 1; i++)
-    token_translations[i] = undeftoken->number;
+    token_translations[i] = undeftoken->content->number;
   symbols_do (symbol_translation_processor, NULL,
               symbol_table, &symbols_sorted);
 }
@@ -977,9 +1008,6 @@ symbols_token_translations_init (void)
 void
 symbols_pack (void)
 {
-  symbols_do (symbol_check_alias_consistency_processor, NULL,
-              symbol_table, &symbols_sorted);
-
   symbols = xcalloc (nsyms, sizeof *symbols);
   symbols_do (symbol_pack_processor, NULL, symbol_table, &symbols_sorted);
 
@@ -998,9 +1026,7 @@ symbols_pack (void)
         else
           {
             symbols[writei] = symbols[readi];
-            symbols[writei]->number = writei;
+            symbols[writei]->content->number = writei;
-            if (symbols[writei]->alias)
-              symbols[writei]->alias->number = writei;
             writei += 1;
           }
       }
@@ -1009,11 +1035,11 @@ symbols_pack (void)
 
   symbols_token_translations_init ();
 
-  if (startsymbol->class == unknown_sym)
+  if (startsymbol->content->class == unknown_sym)
     complain (&startsymbol_location, fatal,
               _("the start symbol %s is undefined"),
               startsymbol->tag);
-  else if (startsymbol->class == token_sym)
+  else if (startsymbol->content->class == token_sym)
     complain (&startsymbol_location, fatal,
               _("the start symbol %s is a token"),
               startsymbol->tag);
@@ -1150,9 +1176,9 @@ static inline bool
 is_assoc_useless (symbol *s)
 {
   return s
-      && s->assoc != undef_assoc
+      && s->content->assoc != undef_assoc
-      && s->assoc != precedence_assoc
+      && s->content->assoc != precedence_assoc
-      && !used_assoc[s->number];
+      && !used_assoc[s->content->number];
 }
 
 /*-------------------------------.
@@ -1184,19 +1210,19 @@ print_precedence_warnings (void)
     {
       symbol *s = symbols[i];
       if (s
-          && s->prec != 0
+          && s->content->prec != 0
           && !prec_nodes[i]->pred
           && !prec_nodes[i]->succ)
         {
           if (is_assoc_useless (s))
-            complain (&s->prec_location, Wprecedence,
+            complain (&s->content->prec_location, Wprecedence,
                       _("useless precedence and associativity for %s"), s->tag);
-          else if (s->assoc == precedence_assoc)
+          else if (s->content->assoc == precedence_assoc)
-            complain (&s->prec_location, Wprecedence,
+            complain (&s->content->prec_location, Wprecedence,
                       _("useless precedence for %s"), s->tag);
         }
       else if (is_assoc_useless (s))
-        complain (&s->prec_location, Wprecedence,
+        complain (&s->content->prec_location, Wprecedence,
                   _("useless associativity for %s, use %%precedence"), s->tag);
     }
   free (used_assoc);

src/symtab.h

@@ -50,6 +50,7 @@ typedef int symbol_number;
 
 
 typedef struct symbol symbol;
+typedef struct sym_content sym_content;
 
 /* Declaration status of a symbol.
 
@@ -82,15 +83,36 @@ typedef enum code_props_type code_props_type;
 
 enum { CODE_PROPS_SIZE = 2 };
 
-/* When extending this structure, be sure to complete
-   symbol_check_alias_consistency.  */
 struct symbol
 {
   /** The key, name of the symbol.  */
   uniqstr tag;
-  /** The location of its first occurrence.  */
+
+  /** The "defining" location.  */
   location location;
 
+  /** Whether \a location is about the first uses as left-hand side
+      symbol of a rule (true), or simply the first occurrence (e.g.,
+      in a %type, or as a rhs symbol of a rule).  The former type of
+      location is more natural in error messages.  This Boolean helps
+      moving from location of the first occurrence to first use as
+      lhs. */
+  bool location_of_lhs;
+
+  /** Points to the other in the symbol-string pair for an alias. */
+  symbol *alias;
+
+  /** Whether this symbol is the alias of another or not. */
+  bool is_alias;
+
+  /** All the info about the pointed symbol is there. */
+  sym_content *content;
+};
+
+struct sym_content
+{
+  symbol *symbol;
+
   /** Its \c \%type.
 
       Beware that this is the type_name as was entered by the user,
@@ -117,10 +139,6 @@ struct symbol
   assoc assoc;
   int user_token_number;
 
-  /* Points to the other in the symbol-string pair for an alias.
-     Special value USER_NUMBER_HAS_STRING_ALIAS in the symbol half of the
-     symbol-string pair for an alias.  */
-  symbol *alias;
   symbol_class class;
   status status;
 };
@@ -128,12 +146,6 @@ struct symbol
 /** Undefined user number.  */
 # define USER_NUMBER_UNDEFINED -1
 
-/* 'symbol->user_token_number == USER_NUMBER_HAS_STRING_ALIAS' means
-   this symbol has a literal string alias.  For instance, '%token foo
-   "foo"' has '"foo"' numbered regularly, and 'foo' numbered as
-   USER_NUMBER_HAS_STRING_ALIAS.  */
-# define USER_NUMBER_HAS_STRING_ALIAS -9991
-
 /* Undefined internal token number.  */
 # define NUMBER_UNDEFINED (-1)
 
@@ -174,6 +186,12 @@ uniqstr symbol_id_get (symbol const *sym);
  */
 void symbol_make_alias (symbol *sym, symbol *str, location loc);
 
+/**
+ * This symbol is used as the lhs of a rule.  Record this location
+ * as definition point, if not already done.
+ */
+void symbol_location_as_lhs_set (symbol *sym, location loc);
+
 /** Set the \c type_name associated with \c sym.
 
     Do nothing if passed 0 as \c type_name.  */

src/tables.c

@@ -290,7 +290,7 @@ action_row (state *s)
 
       /* Do not use any default reduction if there is a shift for
          error */
-      if (sym == errtoken->number)
+      if (sym == errtoken->content->number)
         nodefault = true;
     }
 
@@ -300,7 +300,7 @@ action_row (state *s)
   for (i = 0; i < errp->num; i++)
     {
       symbol *sym = errp->symbols[i];
-      actrow[sym->number] = ACTION_NUMBER_MINIMUM;
+      actrow[sym->content->number] = ACTION_NUMBER_MINIMUM;
     }
 
   /* Turn off default reductions where requested by the user.  See

tests/reduce.at

@@ -172,33 +172,6 @@ input.y:13.1-8: warning: nonterminal useless in grammar: useless8 [-Wother]
 input.y:14.1-8: warning: nonterminal useless in grammar: useless9 [-Wother]
  useless9: '9';
  ^^^^^^^^
-input.y:6.11-13: warning: rule useless in grammar [-Wother]
- useless1: '1';
-           ^^^
-input.y:7.11-13: warning: rule useless in grammar [-Wother]
- useless2: '2';
-           ^^^
-input.y:8.11-13: warning: rule useless in grammar [-Wother]
- useless3: '3';
-           ^^^
-input.y:9.11-13: warning: rule useless in grammar [-Wother]
- useless4: '4';
-           ^^^
-input.y:10.11-13: warning: rule useless in grammar [-Wother]
- useless5: '5';
-           ^^^
-input.y:11.11-13: warning: rule useless in grammar [-Wother]
- useless6: '6';
-           ^^^
-input.y:12.11-13: warning: rule useless in grammar [-Wother]
- useless7: '7';
-           ^^^
-input.y:13.11-13: warning: rule useless in grammar [-Wother]
- useless8: '8';
-           ^^^
-input.y:14.11-13: warning: rule useless in grammar [-Wother]
- useless9: '9';
-           ^^^
 ]])
 
 
@@ -281,18 +254,12 @@ not-reduced.y: warning: 3 rules useless in grammar [-Wother]
 not-reduced.y:14.1-13: warning: nonterminal useless in grammar: not_reachable [-Wother]
  not_reachable: useful  { /* A not reachable action. */ }
  ^^^^^^^^^^^^^
-not-reduced.y:11.6-19: warning: nonterminal useless in grammar: non_productive [-Wother]
+not-reduced.y:17.1-14: warning: nonterminal useless in grammar: non_productive [-Wother]
-    | non_productive    { /* A non productive action. */ }
+ non_productive: non_productive useless_token
-      ^^^^^^^^^^^^^^
+ ^^^^^^^^^^^^^^
 not-reduced.y:11.6-57: warning: rule useless in grammar [-Wother]
     | non_productive    { /* A non productive action. */ }
       ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-not-reduced.y:14.16-56: warning: rule useless in grammar [-Wother]
- not_reachable: useful  { /* A not reachable action. */ }
-                ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
-not-reduced.y:17.17-18.63: warning: rule useless in grammar [-Wother]
- non_productive: non_productive useless_token
-                 ^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 ]])
 
 AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' not-reduced.output]], 0,
@@ -360,14 +327,18 @@ underivable: indirection;
 indirection: underivable;
 ]])
 
-AT_BISON_CHECK([[input.y]], 0, [],
+AT_BISON_CHECK([[-fcaret input.y]], 0, [],
 [[input.y: warning: 2 nonterminals useless in grammar [-Wother]
 input.y: warning: 3 rules useless in grammar [-Wother]
-input.y:5.15-25: warning: nonterminal useless in grammar: underivable [-Wother]
+input.y:6.1-11: warning: nonterminal useless in grammar: underivable [-Wother]
-input.y:6.14-24: warning: nonterminal useless in grammar: indirection [-Wother]
+ underivable: indirection;
+ ^^^^^^^^^^^
+input.y:7.1-11: warning: nonterminal useless in grammar: indirection [-Wother]
+ indirection: underivable;
+ ^^^^^^^^^^^
 input.y:5.15-25: warning: rule useless in grammar [-Wother]
-input.y:6.14-24: warning: rule useless in grammar [-Wother]
+ exp: useful | underivable;
-input.y:7.14-24: warning: rule useless in grammar [-Wother]
+               ^^^^^^^^^^^
 ]])
 
 AT_CHECK([[sed -n '/^Grammar/q;/^$/!p' input.output]], 0,