X-Git-Url: https://git.saurik.com/bison.git/blobdiff_plain/437c2d80006f7c4729cffd329c106de50dbd4acc..02d12d0de29cd35a6fd2acabc551e0d89b3fa242:/src/reader.c

diff --git a/src/reader.c b/src/reader.c
index e85b0420..0fa162d9 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -1,6 +1,7 @@
-/* Input parser for bison
-   Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002
-   Free Software Foundation, Inc.
+/* Input parser for Bison
+
+   Copyright (C) 1984, 1986, 1989, 1992, 1998, 2000, 2001, 2002, 2003,
+   2005, 2006 Free Software Foundation, Inc.
 
    This file is part of Bison, the GNU Compiler Compiler.
 
@@ -16,44 +17,51 @@
 
    You should have received a copy of the GNU General Public License
    along with Bison; see the file COPYING.  If not, write to
-   the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
-   Boston, MA 02111-1307, USA.  */
-
+   the Free Software Foundation, Inc., 51 Franklin Street, Fifth Floor,
+   Boston, MA 02110-1301, USA.  */
 
+#include <config.h>
 #include "system.h"
-#include "quotearg.h"
-#include "getargs.h"
+
+#include <quotearg.h>
+
+#include "complain.h"
+#include "conflicts.h"
 #include "files.h"
-#include "symtab.h"
-#include "symlist.h"
+#include "getargs.h"
 #include "gram.h"
-#include "complain.h"
+#include "muscle_tab.h"
 #include "output.h"
 #include "reader.h"
-#include "conflicts.h"
-#include "muscle_tab.h"
+#include "symlist.h"
+#include "symtab.h"
+
+static void check_and_convert_grammar (void);
 
-static symbol_list_t *grammar = NULL;
-static int start_flag = 0;
+static symbol_list *grammar = NULL;
+static bool start_flag = false;
 merger_list *merge_functions;
 
-/* Nonzero if %union has been seen.  */
-int typed = 0;
+/* Was %union seen?  */
+bool typed = false;
+
+/* Should rules have a default precedence?  */
+bool default_prec = true;
 
 /*-----------------------.
 | Set the start symbol.  |
 `-----------------------*/
 
 void
-grammar_start_symbol_set (symbol_t *s, location_t l)
+grammar_start_symbol_set (symbol *sym, location loc)
 {
   if (start_flag)
-    complain_at (l, _("multiple %s declarations"), "%start");
+    complain_at (loc, _("multiple %s declarations"), "%start");
   else
     {
-      start_flag = 1;
-      startsymbol = s;
-      startsymbol_location = l;
+      start_flag = true;
+      startsymbol = sym;
+      startsymbol_location = loc;
     }
 }
 
@@ -64,47 +72,28 @@ grammar_start_symbol_set (symbol_t *s, location_t l)
 `----------------------------------------------------------------*/
 
 void
-prologue_augment (const char *prologue, location_t location)
+prologue_augment (const char *prologue, location loc)
 {
   struct obstack *oout =
     !typed ? &pre_prologue_obstack : &post_prologue_obstack;
 
-  obstack_fgrow2 (oout, "]b4_syncline([[%d]], [[%s]])[\n",
-	   location.first_line,
-	   quotearg_style (escape_quoting_style, location.file));
+  obstack_fgrow1 (oout, "]b4_syncline(%d, [[", loc.start.line);
+  MUSCLE_OBSTACK_SGROW (oout,
+			quotearg_style (c_quoting_style, loc.start.file));
+  obstack_sgrow (oout, "]])[\n");
   obstack_sgrow (oout, prologue);
 }
 
-
-
-
-/*----------------------.
-| Handle the epilogue.  |
-`----------------------*/
-
-void
-epilogue_set (const char *epilogue, location_t location)
-{
-  obstack_fgrow2 (&muscle_obstack, "]b4_syncline([[%d]], [[%s]])[\n",
-		  location.first_line,
-		  quotearg_style (escape_quoting_style, location.file));
-  obstack_sgrow (&muscle_obstack, epilogue);
-  obstack_1grow (&muscle_obstack, 0);
-  muscle_insert ("epilogue", obstack_finish (&muscle_obstack));
-}
-
-
 
 
- /*-------------------------------------------------------------------.
+/*-------------------------------------------------------------------.
 | Return the merger index for a merging function named NAME, whose   |
 | arguments have type TYPE.  Records the function, if new, in        |
-| merger_list.							     |
+| MERGER_LIST.							     |
 `-------------------------------------------------------------------*/
 
 static int
-get_merge_function (const char* name, const char* type,
-		    location_t loc)
+get_merge_function (uniqstr name, uniqstr type, location loc)
 {
   merger_list *syms;
   merger_list head;
@@ -114,21 +103,21 @@ get_merge_function (const char* name, const char* type,
     return 0;
 
   if (type == NULL)
-    type = "";
+    type = uniqstr_new ("");
 
   head.next = merge_functions;
-  for (syms = &head, n = 1; syms->next != NULL; syms = syms->next, n += 1)
-    if (strcmp (name, syms->next->name) == 0)
+  for (syms = &head, n = 1; syms->next; syms = syms->next, n += 1)
+    if (UNIQSTR_EQ (name, syms->next->name))
       break;
   if (syms->next == NULL)
     {
-      syms->next = XMALLOC (merger_list, 1);
-      syms->next->name = xstrdup (name);
-      syms->next->type = xstrdup (type);
+      syms->next = xmalloc (sizeof syms->next[0]);
+      syms->next->name = uniqstr_new (name);
+      syms->next->type = uniqstr_new (type);
       syms->next->next = NULL;
       merge_functions = head.next;
     }
-  else if (strcmp (type, syms->next->type) != 0)
+  else if (!UNIQSTR_EQ (type, syms->next->type))
     warn_at (loc, _("result type clash on merge function %s: <%s> != <%s>"),
 	     name, type, syms->next->type);
   return n;
@@ -141,11 +130,8 @@ get_merge_function (const char* name, const char* type,
 void
 free_merger_functions (void)
 {
-  merger_list *L0;
-  if (! glr_parser)
-    return;
-  L0 = merge_functions;
-  while (L0 != NULL)
+  merger_list *L0 = merge_functions;
+  while (L0)
     {
       merger_list *L1 = L0->next;
       free (L0);
@@ -155,7 +141,7 @@ free_merger_functions (void)
 
 
 /*-------------------------------------------------------------------.
-| Parse the input grammar into a one symbol_list_t structure.  Each  |
+| Parse the input grammar into a one symbol_list structure.  Each    |
 | rule is represented by a sequence of symbols: the left hand side   |
 | followed by the contents of the right hand side, followed by a     |
 | null pointer instead of a symbol to terminate the rule.  The next  |
@@ -163,23 +149,16 @@ free_merger_functions (void)
 |                                                                    |
 | All actions are copied out, labelled by the rule number they apply |
 | to.                                                                |
-|                                                                    |
-| Bison used to allow some %directives in the rules sections, but    |
-| this is no longer consider appropriate: (i) the documented grammar |
-| doesn't claim it, (ii), it would promote bad style, (iii), error   |
-| recovery for %directives consists in skipping the junk until a `%' |
-| is seen and helrp synchronizing.  This scheme is definitely wrong  |
-| in the rules section.                                              |
 `-------------------------------------------------------------------*/
 
 /* The (currently) last symbol of GRAMMAR. */
-symbol_list_t *grammar_end = NULL;
+static symbol_list *grammar_end = NULL;
 
-/* Append S to the GRAMMAR. */
-void
-grammar_symbol_append (symbol_t *symbol, location_t location)
+/* Append SYM to the grammar.  */
+static void
+grammar_symbol_append (symbol *sym, location loc)
 {
-  symbol_list_t *p = symbol_list_new (symbol, location);
+  symbol_list *p = symbol_list_new (sym, loc);
 
   if (grammar_end)
     grammar_end->next = p;
@@ -187,13 +166,18 @@ grammar_symbol_append (symbol_t *symbol, location_t location)
     grammar = p;
 
   grammar_end = p;
+
+  /* A null SYM stands for an end of rule; it is not an actual
+     part of it.  */
+  if (sym)
+    ++nritems;
 }
 
 /* The rule currently being defined, and the previous rule.
    CURRENT_RULE points to the first LHS of the current rule, while
    PREVIOUS_RULE_END points to the *end* of the previous rule (NULL).  */
-symbol_list_t *current_rule = NULL;
-symbol_list_t *previous_rule_end = NULL;
+symbol_list *current_rule = NULL;
+static symbol_list *previous_rule_end = NULL;
 
 
 /*----------------------------------------------.
@@ -201,25 +185,22 @@ symbol_list_t *previous_rule_end = NULL;
 `----------------------------------------------*/
 
 void
-grammar_rule_begin (symbol_t *lhs, location_t location)
+grammar_current_rule_begin (symbol *lhs, location loc)
 {
   if (!start_flag)
     {
       startsymbol = lhs;
-      startsymbol_location = location;
-      start_flag = 1;
+      startsymbol_location = loc;
+      start_flag = true;
     }
 
   /* Start a new rule and record its lhs.  */
   ++nrules;
-  ++nritems;
-
   previous_rule_end = grammar_end;
-  grammar_symbol_append (lhs, location);
+  grammar_symbol_append (lhs, loc);
   current_rule = grammar_end;
 
   /* Mark the rule's lhs as a nonterminal if not already so.  */
-
   if (lhs->class == unknown_sym)
     {
       lhs->class = nterm_sym;
@@ -227,42 +208,75 @@ grammar_rule_begin (symbol_t *lhs, location_t location)
       ++nvars;
     }
   else if (lhs->class == token_sym)
-    complain_at (location, _("rule given for %s, which is a token"), lhs->tag);
+    complain_at (loc, _("rule given for %s, which is a token"), lhs->tag);
 }
 
-/* Check that the last rule (CURRENT_RULE) is properly defined.  For
-   instance, there should be no type clash on the default action.  */
+
+/*-----------------------------------------------------------------.
+| A symbol is typed if it has a declared %type, or if it is a      |
+| mid-rule symbol (i.e., the generated LHS replacing a mid-rule    |
+| action) that was assigned to, as in `exp: { $$ = 1; } { $$ = $1; |
+| }'.                                                              |
+`-----------------------------------------------------------------*/
+
+static bool
+symbol_typed_p (const symbol_list *s)
+{
+  return (s->sym->type_name
+	  || (s->midrule && s->midrule->used));
+}
+
+/*----------------------------------------------------------------.
+| Check that the rule R is properly defined.  For instance, there |
+| should be no type clash on the default action.                  |
+`----------------------------------------------------------------*/
 
 static void
-grammar_current_rule_check (void)
+grammar_rule_check (const symbol_list *r)
 {
-  symbol_t *lhs = current_rule->sym;
-  char const *lhs_type = lhs->type_name;
-  symbol_t *first_rhs = current_rule->next->sym;
+  /* Type check.
 
-  /* If there is an action, then there is nothing we can do: the user
-     is allowed to shoot herself in the foot.  */
-  if (current_rule->action)
-    return;
+     If there is an action, then there is nothing we can do: the user
+     is allowed to shoot herself in the foot.
 
-  /* Don't worry about the default action if $$ is untyped, since $$'s
+     Don't worry about the default action if $$ is untyped, since $$'s
      value can't be used.  */
-  if (! lhs_type)
-    return;
-
-  /* If $$ is being set in default way, report if any type mismatch.  */
-  if (first_rhs)
+  if (!r->action && r->sym->type_name)
     {
-      const char *rhs_type = first_rhs->type_name ? first_rhs->type_name : "";
-      if (strcmp (lhs_type, rhs_type))
-	complain_at (current_rule->location,
+      symbol *first_rhs = r->next->sym;
+      /* If $$ is being set in default way, report if any type mismatch.  */
+      if (first_rhs)
+	{
+	  char const *lhs_type = r->sym->type_name;
+	  const char *rhs_type =
+	    first_rhs->type_name ? first_rhs->type_name : "";
+	  if (!UNIQSTR_EQ (lhs_type, rhs_type))
+	    warn_at (r->location,
 		     _("type clash on default action: <%s> != <%s>"),
 		     lhs_type, rhs_type);
-    }
-  /* Warn if there is no default for $$ but we need one.  */
-  else
-    complain_at (current_rule->location,
+	}
+      /* Warn if there is no default for $$ but we need one.  */
+      else
+	warn_at (r->location,
 		 _("empty rule for typed nonterminal, and no action"));
+    }
+
+  /* Check that typed symbol values are used.  */
+  {
+    symbol_list const *l = r;
+    int n = 0;
+    for (; l && l->sym; l = l->next, ++n)
+      if (! (l->used
+	     || !symbol_typed_p (l)
+	     /* The default action, $$ = $1, `uses' both.  */
+	     || (!r->action && (n == 0 || n == 1))))
+	{
+	  if (n)
+	    warn_at (r->location, _("unused value: $%d"), n);
+	  else
+	    warn_at (r->location, _("unset value: $$"));
+	}
+  }
 }
 
 
@@ -271,12 +285,12 @@ grammar_current_rule_check (void)
 `-------------------------------------*/
 
 void
-grammar_rule_end (location_t location)
+grammar_current_rule_end (location loc)
 {
   /* Put an empty link in the list to mark the end of this rule  */
   grammar_symbol_append (NULL, grammar_end->location);
-  current_rule->location = location;
-  grammar_current_rule_check ();
+  current_rule->location = loc;
+  grammar_rule_check (current_rule);
 }
 
 
@@ -287,7 +301,7 @@ grammar_rule_end (location_t location)
 | rule.                                                              |
 `-------------------------------------------------------------------*/
 
-void
+static void
 grammar_midrule_action (void)
 {
   /* Since the action was written out with this rule's number, we must
@@ -296,9 +310,9 @@ grammar_midrule_action (void)
 
   /* Make a DUMMY nonterminal, whose location is that of the midrule
      action.  Create the MIDRULE.  */
-  location_t dummy_location = current_rule->action_location;
-  symbol_t *dummy = dummy_symbol_get (dummy_location);
-  symbol_list_t *midrule = symbol_list_new (dummy, dummy_location);
+  location dummy_location = current_rule->action_location;
+  symbol *dummy = dummy_symbol_get (dummy_location);
+  symbol_list *midrule = symbol_list_new (dummy, dummy_location);
 
   /* Make a new rule, whose body is empty, before the current one, so
      that the action just read can belong to it.  */
@@ -309,6 +323,10 @@ grammar_midrule_action (void)
   midrule->action = current_rule->action;
   midrule->action_location = dummy_location;
   current_rule->action = NULL;
+  /* If $$ was used in the action, the LHS of the enclosing rule was
+     incorrectly flagged as used.  */
+  midrule->used = current_rule->used;
+  current_rule->used = false;
 
   if (previous_rule_end)
     previous_rule_end->next = midrule;
@@ -316,38 +334,39 @@ grammar_midrule_action (void)
     grammar = midrule;
 
   /* End the dummy's rule.  */
-  previous_rule_end = symbol_list_new (NULL, dummy_location);
-  previous_rule_end->next = current_rule;
+  midrule->next = symbol_list_new (NULL, dummy_location);
+  grammar_rule_check (midrule);
+  midrule->next->next = current_rule;
 
-  midrule->next = previous_rule_end;
+  previous_rule_end = midrule->next;
 
   /* Insert the dummy nonterminal replacing the midrule action into
-     the current rule.  */
+     the current rule.  Bind it to its dedicated rule.  */
   grammar_current_rule_symbol_append (dummy, dummy_location);
+  grammar_end->midrule = midrule;
 }
 
 /* Set the precedence symbol of the current rule to PRECSYM. */
 
 void
-grammar_current_rule_prec_set (symbol_t *precsym, location_t location)
+grammar_current_rule_prec_set (symbol *precsym, location loc)
 {
   if (current_rule->ruleprec)
-    complain_at (location, _("only one %s allowed per rule"), "%prec");
+    complain_at (loc, _("only one %s allowed per rule"), "%prec");
   current_rule->ruleprec = precsym;
 }
 
 /* Attach dynamic precedence DPREC to the current rule. */
 
 void
-grammar_current_rule_dprec_set (int dprec, location_t location)
+grammar_current_rule_dprec_set (int dprec, location loc)
 {
   if (! glr_parser)
-    warn_at (location, _("%s affects only GLR parsers"), "%dprec");
+    warn_at (loc, _("%s affects only GLR parsers"), "%dprec");
   if (dprec <= 0)
-    complain_at (location,
-		 _("%s must be followed by positive number"), "%dprec");
+    complain_at (loc, _("%s must be followed by positive number"), "%dprec");
   else if (current_rule->dprec != 0)
-    complain_at (location, _("only one %s allowed per rule"), "%dprec");
+    complain_at (loc, _("only one %s allowed per rule"), "%dprec");
   current_rule->dprec = dprec;
 }
 
@@ -355,38 +374,37 @@ grammar_current_rule_dprec_set (int dprec, location_t location)
    rule. */
 
 void
-grammar_current_rule_merge_set (const char* name, location_t location)
+grammar_current_rule_merge_set (uniqstr name, location loc)
 {
   if (! glr_parser)
-    warn_at (location, _("%s affects only GLR parsers"), "%merge");
+    warn_at (loc, _("%s affects only GLR parsers"), "%merge");
   if (current_rule->merger != 0)
-    complain_at (location, _("only one %s allowed per rule"), "%merge");
+    complain_at (loc, _("only one %s allowed per rule"), "%merge");
   current_rule->merger =
-    get_merge_function (name, current_rule->sym->type_name, location);
+    get_merge_function (name, current_rule->sym->type_name, loc);
 }
 
-/* Attach a SYMBOL to the current rule.  If needed, move the previous
+/* Attach SYM to the current rule.  If needed, move the previous
    action as a mid-rule action.  */
 
 void
-grammar_current_rule_symbol_append (symbol_t *symbol, location_t location)
+grammar_current_rule_symbol_append (symbol *sym, location loc)
 {
   if (current_rule->action)
     grammar_midrule_action ();
-  ++nritems;
-  grammar_symbol_append (symbol, location);
+  grammar_symbol_append (sym, loc);
 }
 
 /* Attach an ACTION to the current rule.  If needed, move the previous
    action as a mid-rule action.  */
 
 void
-grammar_current_rule_action_append (const char *action, location_t location)
+grammar_current_rule_action_append (const char *action, location loc)
 {
   if (current_rule->action)
     grammar_midrule_action ();
   current_rule->action = action;
-  current_rule->action_location = location;
+  current_rule->action_location = loc;
 }
 
 
@@ -399,35 +417,41 @@ static void
 packgram (void)
 {
   unsigned int itemno = 0;
-  rule_number_t ruleno = 0;
-  symbol_list_t *p = grammar;
+  rule_number ruleno = 0;
+  symbol_list *p = grammar;
+
+  ritem = xnmalloc (nritems + 1, sizeof *ritem);
+
+  /* This sentinel is used by build_relations in gram.c.  */
+  *ritem++ = 0;
 
-  ritem = XCALLOC (item_number_t, nritems);
-  rules = XCALLOC (rule_t, nrules);
+  rules = xnmalloc (nrules, sizeof *rules);
 
   while (p)
     {
-      symbol_t *ruleprec = p->ruleprec;
+      symbol *ruleprec = p->ruleprec;
       rules[ruleno].user_number = ruleno;
       rules[ruleno].number = ruleno;
       rules[ruleno].lhs = p->sym;
       rules[ruleno].rhs = ritem + itemno;
+      rules[ruleno].prec = NULL;
+      rules[ruleno].dprec = p->dprec;
+      rules[ruleno].merger = p->merger;
+      rules[ruleno].precsym = NULL;
       rules[ruleno].location = p->location;
       rules[ruleno].useful = true;
       rules[ruleno].action = p->action;
       rules[ruleno].action_location = p->action_location;
-      rules[ruleno].dprec = p->dprec;
-      rules[ruleno].merger = p->merger;
 
       p = p->next;
       while (p && p->sym)
 	{
-	  /* item_number_t = symbol_number_t.
+	  /* item_number = symbol_number.
 	     But the former needs to contain more: negative rule numbers. */
 	  ritem[itemno++] = symbol_number_as_item_number (p->sym->number);
 	  /* A rule gets by default the precedence and associativity
 	     of the last token in it.  */
-	  if (p->sym->class == token_sym)
+	  if (p->sym->class == token_sym && default_prec)
 	    rules[ruleno].prec = p->sym;
 	  if (p)
 	    p = p->next;
@@ -463,8 +487,6 @@ packgram (void)
 void
 reader (void)
 {
-  gram_control_t gram_control;
-
   /* Initialize the symbol table.  */
   symbols_new ();
 
@@ -488,20 +510,29 @@ reader (void)
   obstack_init (&pre_prologue_obstack);
   obstack_init (&post_prologue_obstack);
 
-  finput = xfopen (infile, "r");
-  gram_in = finput;
+  gram_in = xfopen (grammar_file, "r");
 
   gram__flex_debug = trace_flag & trace_scan;
   gram_debug = trace_flag & trace_parse;
   scanner_initialize ();
-  gram_parse (&gram_control);
+  gram_parse ();
+
+  if (! complaint_issued)
+    check_and_convert_grammar ();
+
+  xfclose (gram_in);
+}
+
 
-  /* If something went wrong during the parsing, don't try to
-     continue.  */
-  if (complaint_issued)
-    return;
+/*-------------------------------------------------------------.
+| Check the grammar that has just been read, and convert it to |
+| internal form.					       |
+`-------------------------------------------------------------*/
 
-  /* Grammar has been read.  Do some checking */
+static void
+check_and_convert_grammar (void)
+{
+  /* Grammar has been read.  Do some checking.  */
   if (nrules == 0)
     fatal (_("no rules in the input grammar"));
 
@@ -518,12 +549,12 @@ reader (void)
       endtoken->user_token_number = 0;
     }
 
-  /* Insert the initial rule, which line is that of the first rule
+  /* Insert the initial rule, whose line is that of the first rule
      (not that of the start symbol):
 
      accept: %start EOF.  */
   {
-    symbol_list_t *p = symbol_list_new (accept, empty_location);
+    symbol_list *p = symbol_list_new (accept, empty_location);
     p->location = grammar->location;
     p->next = symbol_list_new (startsymbol, empty_location);
     p->next->next = symbol_list_new (endtoken, empty_location);
@@ -534,13 +565,7 @@ reader (void)
     grammar = p;
   }
 
-  if (SYMBOL_NUMBER_MAX < nsyms)
-    fatal (_("too many symbols (tokens plus nonterminals); maximum %d"),
-	   SYMBOL_NUMBER_MAX);
-
-  assert (nsyms == ntokens + nvars);
-
-  xfclose (finput);
+  assert (nsyms <= SYMBOL_NUMBER_MAXIMUM && nsyms == ntokens + nvars);
 
   /* Assign the symbols their symbol numbers.  Write #defines for the
      token symbols into FDEFINES if requested.  */
@@ -549,6 +574,6 @@ reader (void)
   /* Convert the grammar into the format described in gram.h.  */
   packgram ();
 
-  /* The grammar as a symbol_list_t is no longer needed. */
-  LIST_FREE (symbol_list_t, grammar);
+  /* The grammar as a symbol_list is no longer needed. */
+  LIST_FREE (symbol_list, grammar);
 }