* data/glr.c (yyreportSyntaxError): Fix off-by-one error in

checking against YYLAST that caused the parser to miss a potential
alternative in its diagnostic.
Problem reported by Maria Jose Moron Fernandez in
<http://lists.gnu.org/archive/html/bug-bison/2006-05/msg00024.html>.
* data/lalr1.cc (yysyntax_error_): Likewise.
* data/yacc.c (yysyntax_error): Likewise.
* tests/regression.at (_AT_DATA_DANCER_Y): Use static array for
tokens, in case we run into an older C compiler.
(_AT_DATA_EXPECT2_Y, AT_CHECK_EXPECT2): New macros.
Use them to check for the off-by-one error fixed above.

diff --git a/ChangeLog b/ChangeLog
index bd61223b363279d9c6ffdbbc0c57503b00178537..0b94fe9a8b6454e6b02b4bb4595dec6615430266 100644 (file)
--- a/ChangeLog
+++ b/ChangeLog
@@ -1,5 +1,17 @@
 2006-05-14  Paul Eggert  <eggert@cs.ucla.edu>
 
+       * data/glr.c (yyreportSyntaxError): Fix off-by-one error in
+       checking against YYLAST that caused the parser to miss a potential
+       alternative in its diagnostic.
+       Problem reported by Maria Jose Moron Fernandez in
+       <http://lists.gnu.org/archive/html/bug-bison/2006-05/msg00024.html>.
+       * data/lalr1.cc (yysyntax_error_): Likewise.
+       * data/yacc.c (yysyntax_error): Likewise.
+       * tests/regression.at (_AT_DATA_DANCER_Y): Use static array for
+       tokens, in case we run into an older C compiler.
+       (_AT_DATA_EXPECT2_Y, AT_CHECK_EXPECT2): New macros.
+       Use them to check for the off-by-one error fixed above.
+
        * data/yacc.c (yytnamerr): Fix typo: local var should be of type
        YYSIZE_T, not size_t.
        * tests/regression.at (Trivial grammars): New test, to catch

diff --git a/data/glr.c b/data/glr.c
index a3a3f49d994b542b9742f9180086f74a78e6c683..0a4b89996c05b4e9f52cbcb0c36df18a98384f32 100644 (file)
--- a/data/glr.c
+++ b/data/glr.c
@@ -2077,7 +2077,7 @@ yyreportSyntaxError (yyGLRStack* yystackp]b4_user_formals[)
 #if YYERROR_VERBOSE
       int yyn;
       yyn = yypact[yystackp->yytops.yystates[0]->yylrState];
-      if (YYPACT_NINF < yyn && yyn < YYLAST)
+      if (YYPACT_NINF < yyn && yyn <= YYLAST)
        {
          yySymbol yytoken = YYTRANSLATE (yychar);
          size_t yysize0 = yytnamerr (NULL, yytokenName (yytoken));
@@ -2104,7 +2104,7 @@ yyreportSyntaxError (yyGLRStack* yystackp]b4_user_formals[)
          int yyxbegin = yyn < 0 ? -yyn : 0;
 
          /* Stay within bounds of both yycheck and yytname.  */
-         int yychecklim = YYLAST - yyn;
+         int yychecklim = YYLAST - yyn + 1;
          int yyxend = yychecklim < YYNTOKENS ? yychecklim : YYNTOKENS;
          int yycount = 1;
 

diff --git a/data/lalr1.cc b/data/lalr1.cc
index 527a8de796b146e9d9adf8fa50307fefc0f8a386..abcdcd5d604163278d29f19f5b5919ad55cfd556 100644 (file)
--- a/data/lalr1.cc
+++ b/data/lalr1.cc
@@ -838,14 +838,14 @@ b4_error_verbose_if([, int tok])[)
     YYUSE (yystate);
 #if YYERROR_VERBOSE
     int yyn = yypact_[yystate];
-    if (yypact_ninf_ < yyn && yyn < yylast_)
+    if (yypact_ninf_ < yyn && yyn <= yylast_)
       {
        /* Start YYX at -YYN if negative to avoid negative indexes in
           YYCHECK.  */
        int yyxbegin = yyn < 0 ? -yyn : 0;
 
        /* Stay within bounds of both yycheck and yytname.  */
-       int yychecklim = yylast_ - yyn;
+       int yychecklim = yylast_ - yyn + 1;
        int yyxend = yychecklim < yyntokens_ ? yychecklim : yyntokens_;
        int count = 0;
        for (int x = yyxbegin; x < yyxend; ++x)

diff --git a/data/yacc.c b/data/yacc.c
index 61e2fddff3600d714cab4d3a2f7ab32b773078c9..289bee8ac68cc31d78817a98f4a39f105af82134 100644 (file)
--- a/data/yacc.c
+++ b/data/yacc.c
@@ -847,7 +847,7 @@ yysyntax_error (char *yyresult, int yystate, int yychar)
 {
   int yyn = yypact[yystate];
 
-  if (! (YYPACT_NINF < yyn && yyn < YYLAST))
+  if (! (YYPACT_NINF < yyn && yyn <= YYLAST))
     return 0;
   else
     {
@@ -885,7 +885,7 @@ yysyntax_error (char *yyresult, int yystate, int yychar)
       int yyxbegin = yyn < 0 ? -yyn : 0;
 
       /* Stay within bounds of both yycheck and yytname.  */
-      int yychecklim = YYLAST - yyn;
+      int yychecklim = YYLAST - yyn + 1;
       int yyxend = yychecklim < YYNTOKENS ? yychecklim : YYNTOKENS;
       int yycount = 1;
 

diff --git a/tests/regression.at b/tests/regression.at
index 5e68b95c2cced735a5db3727eb0c70fc11aef4b5..c5ceaf1473ef2ac0698583628b657ac3d541ee50 100644 (file)
--- a/tests/regression.at
+++ b/tests/regression.at
@@ -824,7 +824,7 @@ static int
 yylex (AT_LALR1_CC_IF([int *lval], [void]))
 [{
   static int toknum = 0;
-  int tokens[] =
+  static int tokens[] =
     {
       ':', -1
     };
@@ -864,3 +864,100 @@ AT_CLEANUP
 AT_CHECK_DANCER()
 AT_CHECK_DANCER([%glr-parser])
 AT_CHECK_DANCER([%skeleton "lalr1.cc"])
+
+
+## ------------------------------------------ ##
+## Diagnostic that expects two alternatives.  ##
+## ------------------------------------------ ##
+
+
+# _AT_DATA_EXPECT2_Y(BISON-OPTIONS)
+# --------------------------------
+m4_define([_AT_DATA_EXPECT2_Y],
+[AT_DATA_GRAMMAR([expect2.y],
+[%{
+static int yylex (AT_LALR1_CC_IF([int *], [void]));
+AT_LALR1_CC_IF([],
+[#include <stdio.h>
+static void yyerror (const char *);])
+%}
+$1
+%defines
+%error-verbose
+%token A 1000
+%token B
+
+%%
+program: /* empty */
+ | program e ';'
+ | program error ';';
+
+e: e '+' t | t;
+t: A | B;
+
+%%
+AT_LALR1_CC_IF(
+[/* A C++ error reporting function. */
+void
+yy::parser::error (const location&, const std::string& m)
+{
+  std::cerr << m << std::endl;
+}
+
+int
+yyparse ()
+{
+  yy::parser parser;
+  return parser.parse ();
+}
+],
+[static void
+yyerror (const char *s)
+{
+  fprintf (stderr, "%s\n", s);
+}])
+
+static int
+yylex (AT_LALR1_CC_IF([int *lval], [void]))
+[{
+  static int toknum = 0;
+  static int tokens[] =
+    {
+      1000, '+', '+', -1
+    };
+  ]AT_LALR1_CC_IF([*lval = 0; /* Pacify GCC.  */])[
+  return tokens[toknum++];
+}]
+
+int
+main (void)
+{
+  return yyparse ();
+}
+])
+])# _AT_DATA_EXPECT2_Y
+
+
+# AT_CHECK_EXPECT2(BISON-OPTIONS)
+# ------------------------------
+# Generate the grammar, compile it, run it.
+m4_define([AT_CHECK_EXPECT2],
+[AT_SETUP([Expecting two tokens $1])
+AT_BISON_OPTION_PUSHDEFS([$1])
+_AT_DATA_EXPECT2_Y([$1])
+AT_CHECK([bison -o expect2.c expect2.y])
+AT_LALR1_CC_IF(
+  [AT_CHECK([bison -o expect2.cc expect2.y])
+   AT_COMPILE_CXX([expect2])],
+  [AT_CHECK([bison -o expect2.c expect2.y])
+   AT_COMPILE([expect2])])
+AT_PARSER_CHECK([./expect2], 1, [],
+[syntax error, unexpected '+', expecting A or B
+])
+AT_BISON_OPTION_POPDEFS
+AT_CLEANUP
+])
+
+AT_CHECK_EXPECT2()
+AT_CHECK_EXPECT2([%glr-parser])
+AT_CHECK_EXPECT2([%skeleton "lalr1.cc"])