X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/331dbc1bb7fac0b108adc5591bd9308a39629287..0d8a73638f6acd5881571a28421215ea061e2e35:/src/reader.c

diff --git a/src/reader.c b/src/reader.c
index 4fa1aaea..5ee5093d 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -40,12 +40,16 @@ typedef struct symbol_list
   struct symbol_list *next;
   bucket *sym;
   int line;
+
   /* The action is attached to the LHS of a rule. */
   const char *action;
   int action_line;
+
+  /* The guard is attached to the LHS of a rule. */
+  const char *guard;
+  int guard_line;
   bucket *ruleprec;
-}
-symbol_list;
+} symbol_list;
 
 int lineno;
 char **tags;
@@ -64,9 +68,10 @@ static int typed;
 /* Incremented for each %left, %right or %nonassoc seen */
 static int lastprec;
 
-static bucket *errtoken;
-static bucket *undeftoken;
-
+static bucket *errtoken = NULL;
+static bucket *undeftoken = NULL;
+static bucket *eoftoken = NULL;
+static bucket *axiom = NULL;
 
 static symbol_list *
 symbol_list_new (bucket *sym)
@@ -75,6 +80,10 @@ symbol_list_new (bucket *sym)
   res->next = NULL;
   res->sym = sym;
   res->line = lineno;
+  res->action = NULL;
+  res->action_line = 0;
+  res->guard = NULL;
+  res->guard_line = 0;
   res->ruleprec = NULL;
   return res;
 }
@@ -326,9 +335,16 @@ copy_at (FILE *fin, struct obstack *oout, int stack_offset)
 
       ungetc (c, fin);
       n = read_signed_integer (fin);
-
-      obstack_fgrow1 (oout, "yylsp[%d]", n - stack_offset);
-      locations_flag = 1;
+      if (n > stack_offset)
+	complain (_("invalid value: %s%d"), "@", n);
+      else
+	{
+	  /* Offset is always 0 if parser has already popped the stack
+	     pointer.  */
+	  obstack_fgrow1 (oout, "yylsp[%d]",
+			  n - (semantic_parser ? 0 : stack_offset));
+	  locations_flag = 1;
+	}
     }
   else
     {
@@ -383,16 +399,24 @@ copy_dollar (FILE *fin, struct obstack *oout,
       ungetc (c, fin);
       n = read_signed_integer (fin);
 
-      if (!type_name && n > 0)
-	type_name = get_type_name (n, rule);
-
-      obstack_fgrow1 (oout, "yyvsp[%d]", n - stack_offset);
-
-      if (type_name)
-	obstack_fgrow1 (oout, ".%s", type_name);
-      if (!type_name && typed)
-	complain (_("$%d of `%s' has no declared type"),
-		  n, rule->sym->tag);
+      if (n > stack_offset)
+	complain (_("invalid value: %s%d"), "$", n);
+      else
+	{
+	  if (!type_name && n > 0)
+	    type_name = get_type_name (n, rule);
+
+	  /* Offset is always 0 if parser has already popped the stack
+	     pointer.  */
+	  obstack_fgrow1 (oout, "yyvsp[%d]",
+			  n - (semantic_parser ? 0 : stack_offset));
+
+	  if (type_name)
+	    obstack_fgrow1 (oout, ".%s", type_name);
+	  if (!type_name && typed)
+	    complain (_("$%d of `%s' has no declared type"),
+		      n, rule->sym->tag);
+	}
     }
   else
     {
@@ -418,7 +442,7 @@ copy_definition (void)
     {
       obstack_fgrow2 (&attrs_obstack, muscle_find ("linef"),
 		      lineno, quotearg_style (c_quoting_style,
-					      muscle_find("filename")));
+					      muscle_find ("filename")));
     }
 
   after_percent = 0;
@@ -550,6 +574,9 @@ parse_token_decl (symbol_class what_is, symbol_class what_is_not)
       else if (symbol && token == tok_number)
 	{
 	  symbol->user_token_number = numval;
+	  /* User defined EOF token? */
+	  if (numval == 0)
+	    eoftoken = symbol;
 	}
       else
 	{
@@ -874,12 +901,13 @@ parse_thong_decl (void)
   nsyms--;
 }
 
+
 static void
 parse_muscle_decl (void)
 {
   int ch = ungetc (skip_white_space (), finput);
-  char* muscle_key;
-  char* muscle_value;
+  char *muscle_key;
+  char *muscle_value;
 
   /* Read key. */
   if (!isalpha (ch) && ch != '_')
@@ -1072,68 +1100,61 @@ read_declarations (void)
 | matching `}' into the actions file.  STACK_OFFSET is the number of |
 | values in the current rule so far, which says where to find `$0'   |
 | with respect to the top of the stack.                              |
+|                                                                    |
+| This routine is used both for actions and guards.  Only            |
+| ACTION_OBSTACK is used, but this is fine, since we use only        |
+| pointers to relevant portions inside this obstack.                 |
 `-------------------------------------------------------------------*/
 
 static void
-copy_action (symbol_list *rule, int stack_offset)
+parse_braces (symbol_list *rule, int stack_offset)
 {
   int c;
   int count;
 
-  /* offset is always 0 if parser has already popped the stack pointer */
-  if (semantic_parser)
-    stack_offset = 0;
-
   count = 1;
-  c = getc (finput);
-
   while (count > 0)
     {
-      while (c != '}')
-	{
-	  switch (c)
-	    {
-	    case '\n':
-	      obstack_1grow (&action_obstack, c);
-	      lineno++;
-	      break;
-
-	    case '{':
-	      obstack_1grow (&action_obstack, c);
-	      count++;
-	      break;
-
-	    case '\'':
-	    case '"':
-	      copy_string (finput, &action_obstack, c);
-	      break;
+      while ((c = getc (finput)) != '}')
+	switch (c)
+	  {
+	  case '\n':
+	    obstack_1grow (&action_obstack, c);
+	    lineno++;
+	    break;
 
-	    case '/':
-	      copy_comment (finput, &action_obstack);
-	      break;
+	  case '{':
+	    obstack_1grow (&action_obstack, c);
+	    count++;
+	    break;
 
-	    case '$':
-	      copy_dollar (finput, &action_obstack,
-			   rule, stack_offset);
-	      break;
+	  case '\'':
+	  case '"':
+	    copy_string (finput, &action_obstack, c);
+	    break;
 
-	    case '@':
-	      copy_at (finput, &action_obstack,
-		       stack_offset);
-	      break;
+	  case '/':
+	    copy_comment (finput, &action_obstack);
+	    break;
 
-	    case EOF:
-	      fatal (_("unmatched %s"), "`{'");
+	  case '$':
+	    copy_dollar (finput, &action_obstack,
+			 rule, stack_offset);
+	    break;
 
-	    default:
-	      obstack_1grow (&action_obstack, c);
-	    }
+	  case '@':
+	    copy_at (finput, &action_obstack,
+		     stack_offset);
+	    break;
 
-	  c = getc (finput);
-	}
+	  case EOF:
+	    fatal (_("unmatched %s"), "`{'");
 
-      /* above loop exits when c is '}' */
+	  default:
+	    obstack_1grow (&action_obstack, c);
+	  }
 
+      /* Above loop exits when C is '}'.  */
       if (--count)
 	{
 	  obstack_1grow (&action_obstack, c);
@@ -1142,108 +1163,29 @@ copy_action (symbol_list *rule, int stack_offset)
     }
 
   obstack_1grow (&action_obstack, '\0');
-  rule->action = obstack_finish (&action_obstack);
-  rule->action_line = lineno;
 }
-
-/*-------------------------------------------------------------------.
-| After `%guard' is seen in the input file, copy the actual guard    |
-| into the guards file.  If the guard is followed by an action, copy |
-| that into the actions file.  STACK_OFFSET is the number of values  |
-| in the current rule so far, which says where to find `$0' with     |
-| respect to the top of the stack, for the simple parser in which    |
-| the stack is not popped until after the guard is run.              |
-`-------------------------------------------------------------------*/
+
 
 static void
-copy_guard (symbol_list *rule, int stack_offset)
+parse_action (symbol_list *rule, int stack_offset)
 {
-  int c;
-  int count;
-  int brace_flag = 0;
-
-  /* offset is always 0 if parser has already popped the stack pointer */
-  if (semantic_parser)
-    stack_offset = 0;
-
-  obstack_fgrow1 (&guard_obstack, "\ncase %d:\n", nrules);
-  if (!no_lines_flag)
-    obstack_fgrow2 (&guard_obstack, muscle_find ("linef"),
-		    lineno, quotearg_style (c_quoting_style,
-					    muscle_find ("filename")));
-  obstack_1grow (&guard_obstack, '{');
-
-  count = 0;
-  c = getc (finput);
-
-  while (brace_flag ? (count > 0) : (c != ';'))
-    {
-      switch (c)
-	{
-	case '\n':
-	  obstack_1grow (&guard_obstack, c);
-	  lineno++;
-	  break;
-
-	case '{':
-	  obstack_1grow (&guard_obstack, c);
-	  brace_flag = 1;
-	  count++;
-	  break;
-
-	case '}':
-	  obstack_1grow (&guard_obstack, c);
-	  if (count > 0)
-	    count--;
-	  else
-	    {
-	      complain (_("unmatched %s"), "`}'");
-	      c = getc (finput);	/* skip it */
-	    }
-	  break;
-
-	case '\'':
-	case '"':
-	  copy_string (finput, &guard_obstack, c);
-	  break;
-
-	case '/':
-	  copy_comment (finput, &guard_obstack);
-	  break;
-
-	case '$':
-	  copy_dollar (finput, &guard_obstack, rule, stack_offset);
-	  break;
-
-	case '@':
-	  copy_at (finput, &guard_obstack, stack_offset);
-	  break;
-
-	case EOF:
-	  fatal ("%s", _("unterminated %guard clause"));
-
-	default:
-	  obstack_1grow (&guard_obstack, c);
-	}
-
-      if (c != '}' || count != 0)
-	c = getc (finput);
-    }
+  rule->action_line = lineno;
+  parse_braces (rule, stack_offset);
+  rule->action = obstack_finish (&action_obstack);
+}
 
-  c = skip_white_space ();
 
-  obstack_sgrow (&guard_obstack, ";\n    break;}");
-  if (c == '{')
-    copy_action (rule, stack_offset);
-  else if (c == '=')
-    {
-      c = getc (finput);	/* why not skip_white_space -wjh */
-      if (c == '{')
-	copy_action (rule, stack_offset);
-    }
-  else
-    ungetc (c, finput);
+static void
+parse_guard (symbol_list *rule, int stack_offset)
+{
+  token_t t = lex ();
+  if (t != tok_left_curly)
+    complain (_("invalid %s declaration"), "%guard");
+  rule->guard_line = lineno;
+  parse_braces (rule, stack_offset);
+  rule->guard = obstack_finish (&action_obstack);
 }
+
 
 
 /*-------------------------------------------------------------------.
@@ -1446,7 +1388,7 @@ readgram (void)
 	      }
 	    else		/* handle an action.  */
 	      {
-		copy_action (crule, rulelength);
+		parse_action (crule, rulelength);
 		action_flag = 1;
 		xactions++;	/* JF */
 	      }
@@ -1465,20 +1407,22 @@ readgram (void)
 	    crule->ruleprec = symval;
 	    t = lex ();
 	  }
+
 	if (t == tok_guard)
 	  {
 	    if (!semantic_parser)
 	      complain (_("%%guard present but %%semantic_parser not specified"));
 
-	    copy_guard (crule, rulelength);
+	    parse_guard (crule, rulelength);
 	    t = lex ();
 	  }
-	else if (t == tok_left_curly)
+
+	if (t == tok_left_curly)
 	  {
 	    /* This case never occurs -wjh */
 	    if (action_flag)
 	      complain (_("two actions at end of one rule"));
-	    copy_action (crule, rulelength);
+	    parse_action (crule, rulelength);
 	    action_flag = 1;
 	    xactions++;	/* -wjh */
 	    t = lex ();
@@ -1507,6 +1451,18 @@ readgram (void)
 	t = lex ();
       }
 
+  /* Insert the initial rule:
+
+     axiom: %start EOF.  */
+  p = symbol_list_new (axiom);
+  p->next = symbol_list_new (startval);
+  p->next->next = symbol_list_new (eoftoken);
+  p->next->next->next = symbol_list_new (NULL);
+  p->next->next->next->next = grammar;
+  nrules += 1;
+  nitems += 3;
+  grammar = p;
+  startval = axiom;
 
   /* grammar has been read.  Do some checking */
 
@@ -1546,7 +1502,7 @@ read_additionnal_code (void)
     {
       obstack_fgrow2 (&el_obstack, muscle_find ("linef"),
 		      lineno, quotearg_style (c_quoting_style,
-					      muscle_find("filename")));
+					      muscle_find ("filename")));
     }
 
   while ((c = getc (finput)) != EOF)
@@ -1609,7 +1565,6 @@ packsymbols (void)
   bucket *bp = NULL;
   int tokno = 1;
   int last_user_token_number;
-  static char DOLLAR[] = "$";
 
   tags = XCALLOC (char *, nsyms + 1);
   user_toknums = XCALLOC (short, nsyms + 1);
@@ -1617,10 +1572,6 @@ packsymbols (void)
   sprec = XCALLOC (short, nsyms);
   sassoc = XCALLOC (short, nsyms);
 
-  /* The EOF token. */
-  tags[0] = DOLLAR;
-  user_toknums[0] = 0;
-
   max_user_token_number = 256;
   last_user_token_number = 256;
 
@@ -1632,11 +1583,18 @@ packsymbols (void)
 	}
       else if (bp->alias)
 	{
-	  /* this symbol and its alias are a single token defn.
-	     allocate a tokno, and assign to both check agreement of
-	     ->prec and ->assoc fields and make both the same */
-	  if (bp->value == 0)
-	    bp->value = bp->alias->value = tokno++;
+	  /* This symbol and its alias are a single token defn.
+	     Allocate a tokno, and assign to both check agreement of
+	     prec and assoc fields and make both the same */
+	  if (bp->value == -1)
+	    {
+	      if (bp == eoftoken || bp->alias == eoftoken)
+		bp->value = bp->alias->value = 0;
+	      else
+		{
+		  bp->value = bp->alias->value = tokno++;
+		}
+	    }
 
 	  if (bp->prec != bp->alias->prec)
 	    {
@@ -1662,13 +1620,17 @@ packsymbols (void)
 		bp->assoc = bp->alias->assoc;
 	    }
 
+	  /* Do not do processing below for SALIASs.  */
 	  if (bp->user_token_number == SALIAS)
-	    continue;		/* do not do processing below for SALIASs */
+	    continue;
 
 	}
-      else			/* bp->class == token_sym */
+      else /* bp->class == token_sym */
 	{
-	  bp->value = tokno++;
+	  if (bp == eoftoken)
+	    bp->value = 0;
+	  else
+	    bp->value = tokno++;
 	}
 
       if (bp->class == token_sym)
@@ -1707,13 +1669,11 @@ symbols_save (void)
 {
   struct obstack tokendefs;
   bucket *bp;
-  char *cp, *symbol;
-  char c;
   obstack_init (&tokendefs);
 
   for (bp = firstsymbol; bp; bp = bp->next)
     {
-      symbol = bp->tag;                /* get symbol */
+      char *symbol = bp->tag;                /* get symbol */
 
       if (bp->value >= ntokens)
 	continue;
@@ -1733,17 +1693,15 @@ symbols_save (void)
 	}
 
       /* Don't #define nonliteral tokens whose names contain periods.  */
-      cp = symbol;
-      while ((c = *cp++) && c != '.');
-      if (c != '\0')
+      if (strchr (symbol, '.'))
 	continue;
 
-      obstack_fgrow2 (&tokendefs, "# define\t%s\t%d\n",
+      obstack_fgrow2 (&tokendefs, "# define %s\t%d\n",
 		      symbol, bp->user_token_number);
       if (semantic_parser)
 	/* FIXME: This is probably wrong, and should be just as
 	   above. --akim.  */
-	obstack_fgrow2 (&tokendefs, "# define\tT%s\t%d\n", symbol, bp->value);
+	obstack_fgrow2 (&tokendefs, "# define T%s\t%d\n", symbol, bp->value);
     }
 
   obstack_1grow (&tokendefs, 0);
@@ -1764,6 +1722,10 @@ packgram (void)
   int ruleno;
   symbol_list *p;
 
+  /* We use short to index items.  */
+  if (nitems >= MAXSHORT)
+    fatal (_("too many items (max %d)"), MAXSHORT);
+
   ritem = XCALLOC (short, nitems + 1);
   rule_table = XCALLOC (rule_t, nrules) - 1;
 
@@ -1780,6 +1742,8 @@ packgram (void)
       rule_table[ruleno].useful = TRUE;
       rule_table[ruleno].action = p->action;
       rule_table[ruleno].action_line = p->action_line;
+      rule_table[ruleno].guard = p->guard;
+      rule_table[ruleno].guard_line = p->guard_line;
 
       p = p->next;
       while (p && p->sym)
@@ -1813,6 +1777,8 @@ packgram (void)
     }
 
   ritem[itemno] = 0;
+  nritems = itemno;
+  assert (nritems == nitems);
 
   if (trace_flag)
     ritem_print (stderr);
@@ -1832,7 +1798,7 @@ reader (void)
   start_flag = 0;
   startval = NULL;		/* start symbol not specified yet. */
 
-  nsyms = 1;
+  nsyms = 0;
   nvars = 0;
   nrules = 0;
   nitems = 0;
@@ -1854,6 +1820,11 @@ reader (void)
   /* Initialize the symbol table.  */
   tabinit ();
 
+  /* Construct the axiom symbol. */
+  axiom = getsym ("$axiom");
+  axiom->class = nterm_sym;
+  axiom->value = nvars++;
+
   /* Construct the error token */
   errtoken = getsym ("error");
   errtoken->class = token_sym;
@@ -1868,7 +1839,6 @@ reader (void)
   /* Initialize the obstacks. */
   obstack_init (&action_obstack);
   obstack_init (&attrs_obstack);
-  obstack_init (&guard_obstack);
   obstack_init (&output_obstack);
 
   finput = xfopen (infile, "r");
@@ -1877,6 +1847,16 @@ reader (void)
      TABLE_OBSTACK and FDEFINES file.  Also notice any %token, %left,
      etc. found there.  */
   read_declarations ();
+
+  /* If the user did not define her EOFTOKEN, do it now. */
+  if (!eoftoken)
+    {
+      eoftoken = getsym ("$");
+      eoftoken->class = token_sym;
+      /* Value specified by POSIX.  */
+      eoftoken->user_token_number = 0;
+    }
+
   /* Read in the grammar, build grammar in list form.  Write out
      guards and actions.  */
   readgram ();