+static inline bool
+is_dot_or_dash (char ch)
+{
+ return ch == '.' || ch == '-';
+}
+
+static inline bool
+contains_dot_or_dash (const char* p)
+{
+ for (; *p; ++p)
+ if (is_dot_or_dash (*p))
+ return true;
+ return false;
+}
+
+/* Defines a variant of a symbolic name resolution. */
+typedef struct
+{
+ /* Index in symbol list. */
+ unsigned symbol_index;
+
+ /* Matched symbol id and loc. */
+ uniqstr id;
+ location loc;
+
+ /* Hiding named reference. */
+ named_ref* hidden_by;
+
+ /* Error flags. May contain zero (no errors) or
+ a combination of VARIANT_* values. */
+ unsigned err;
+} variant;
+
+/* Set when the variant refers to a symbol hidden
+ by an explicit symbol reference. */
+#define VARIANT_HIDDEN (1 << 0)
+
+/* Set when the variant refers to a symbol containing
+ dots or dashes. Will require explicit bracketing. */
+#define VARIANT_BAD_BRACKETING (1 << 1)
+
+/* Set when the variant refers to a symbol which is
+ not visible from current midrule. */
+#define VARIANT_NOT_VISIBLE_FROM_MIDRULE (1 << 2)
+
+static variant *variant_table = 0;
+static unsigned variant_table_size = 0;
+static unsigned variant_count = 0;
+
+static variant *
+variant_table_grow (void)
+{
+ ++variant_count;
+ if (variant_count > variant_table_size)
+ {
+ while (variant_count > variant_table_size)
+ variant_table_size = 2 * variant_table_size + 3;
+ variant_table = xnrealloc (variant_table, variant_table_size,
+ sizeof *variant_table);
+ }
+ return &variant_table[variant_count - 1];
+}
+
+static void
+variant_table_free (void)
+{
+ free (variant_table);
+ variant_table = 0;
+ variant_table_size = variant_count = 0;
+}
+
+static char *
+find_prefix_end (const char *prefix, char *begin, char *end)
+{
+ char *ptr = begin;
+
+ for (; *prefix && ptr != end; ++prefix, ++ptr)
+ if (*prefix != *ptr)
+ return 0;
+
+ if (*prefix)
+ return 0;
+
+ return ptr;
+}
+
+static variant *
+variant_add (uniqstr id, location id_loc, unsigned symbol_index,
+ char *cp, char *cp_end, bool explicit_bracketing)
+{
+ char *prefix_end;
+
+ prefix_end = find_prefix_end (id, cp, cp_end);
+ if (prefix_end &&
+ (prefix_end == cp_end ||
+ (!explicit_bracketing && is_dot_or_dash (*prefix_end))))
+ {
+ variant *r = variant_table_grow ();
+ r->symbol_index = symbol_index;
+ r->id = id;
+ r->loc = id_loc;
+ r->hidden_by = NULL;
+ r->err = 0;
+ return r;
+ }
+ else
+ return NULL;
+}
+
+static const char *
+get_at_spec(unsigned symbol_index)
+{
+ static char at_buf[20];
+ if (symbol_index == 0)
+ strcpy (at_buf, "$$");
+ else
+ snprintf (at_buf, sizeof at_buf, "$%u", symbol_index);
+ return at_buf;
+}
+
+static void
+show_sub_messages (const char* cp, bool explicit_bracketing,
+ int midrule_rhs_index, char dollar_or_at, bool is_warning)
+{
+ unsigned i;
+
+ for (i = 0; i < variant_count; ++i)
+ {
+ const variant *var = &variant_table[i];
+ const char *at_spec = get_at_spec (var->symbol_index);
+
+ if (var->err == 0)
+ {
+ if (is_warning)
+ warn_at (var->loc, _(" refers to: %c%s at %s"),
+ dollar_or_at, var->id, at_spec);
+ else
+ complain_at (var->loc, _(" refers to: %c%s at %s"),
+ dollar_or_at, var->id, at_spec);
+ }
+ else
+ {
+ static struct obstack msg_buf;
+ const char *tail = explicit_bracketing ? "" :
+ cp + strlen (var->id);
+ const char *id = var->hidden_by ? var->hidden_by->id :
+ var->id;
+ location id_loc = var->hidden_by ? var->hidden_by->loc :
+ var->loc;
+
+ /* Create the explanation message. */
+ obstack_init (&msg_buf);
+
+ obstack_fgrow1 (&msg_buf, " possibly meant: %c", dollar_or_at);
+ if (contains_dot_or_dash (id))
+ obstack_fgrow1 (&msg_buf, "[%s]", id);
+ else
+ obstack_sgrow (&msg_buf, id);
+ obstack_sgrow (&msg_buf, tail);
+
+ if (var->err & VARIANT_HIDDEN)
+ {
+ obstack_fgrow1 (&msg_buf, ", hiding %c", dollar_or_at);
+ if (contains_dot_or_dash (var->id))
+ obstack_fgrow1 (&msg_buf, "[%s]", var->id);
+ else
+ obstack_sgrow (&msg_buf, var->id);
+ obstack_sgrow (&msg_buf, tail);
+ }
+
+ obstack_fgrow1 (&msg_buf, " at %s", at_spec);
+
+ if (var->err & VARIANT_NOT_VISIBLE_FROM_MIDRULE)
+ obstack_fgrow1 (&msg_buf, ", cannot be accessed from "
+ "mid-rule action at $%d", midrule_rhs_index);
+
+ obstack_1grow (&msg_buf, '\0');
+ if (is_warning)
+ warn_at (id_loc, _("%s"), (char *) obstack_finish (&msg_buf));
+ else
+ complain_at (id_loc, _("%s"), (char *) obstack_finish (&msg_buf));
+ obstack_free (&msg_buf, 0);
+ }
+ }
+}
+
+/* Returned from "parse_ref" when the reference
+ is inappropriate. */
+#define INVALID_REF (INT_MIN)
+
+/* Returned from "parse_ref" when the reference
+ points to LHS ($$) of the current rule or midrule. */
+#define LHS_REF (INT_MIN + 1)
+
+/* Parse named or positional reference. In case of positional
+ references, can return negative values for $-n "deep" stack
+ accesses. */
+static long int
+parse_ref (char *cp, symbol_list *rule, int rule_length,
+ int midrule_rhs_index, char *text, location text_loc,
+ char dollar_or_at)
+{
+ symbol_list *l;
+ char *cp_end;
+ bool explicit_bracketing;
+ unsigned i;
+ unsigned valid_variants = 0;
+ unsigned valid_variant_index = 0;
+
+ if ('$' == *cp)
+ return LHS_REF;
+
+ if (c_isdigit (*cp) || (*cp == '-' && c_isdigit (* (cp + 1))))
+ {
+ long int num = strtol (cp, &cp, 10);
+ if (1 - INT_MAX + rule_length <= num && num <= rule_length)
+ return num;
+ else
+ {
+ complain_at (text_loc, _("integer out of range: %s"),
+ quote (text));
+ return INVALID_REF;
+ }
+ }
+
+ if ('[' == *cp)
+ {
+ /* Ignore the brackets. */
+ char *p;
+ for (p = ++cp; *p != ']'; ++p)
+ continue;
+ cp_end = p;
+
+ explicit_bracketing = true;
+ }
+ else
+ {
+ /* Take all characters of the name. */
+ char* p;
+ for (p = cp; *p; ++p)
+ if (is_dot_or_dash (*p))
+ {
+ ref_tail_fields = p;
+ break;
+ }
+ for (p = cp; *p; ++p)
+ continue;
+ cp_end = p;
+
+ explicit_bracketing = false;
+ }
+
+ /* Add all relevant variants. */
+ {
+ unsigned symbol_index;
+ variant_count = 0;
+ for (symbol_index = 0, l = rule; !symbol_list_null (l);
+ ++symbol_index, l = l->next)
+ {
+ variant *var;
+ if (l->content_type != SYMLIST_SYMBOL)
+ continue;
+
+ var = variant_add (l->content.sym->tag, l->sym_loc,
+ symbol_index, cp, cp_end, explicit_bracketing);
+ if (var && l->named_ref)
+ var->hidden_by = l->named_ref;
+
+ if (l->named_ref)
+ variant_add (l->named_ref->id, l->named_ref->loc,
+ symbol_index, cp, cp_end, explicit_bracketing);
+ }
+ }
+
+ /* Check errors. */
+ for (i = 0; i < variant_count; ++i)
+ {
+ variant *var = &variant_table[i];
+ unsigned symbol_index = var->symbol_index;
+
+ /* Check visibility from mid-rule actions. */
+ if (midrule_rhs_index != 0
+ && (symbol_index == 0 || midrule_rhs_index < symbol_index))
+ var->err |= VARIANT_NOT_VISIBLE_FROM_MIDRULE;
+
+ /* Check correct bracketing. */
+ if (!explicit_bracketing && contains_dot_or_dash (var->id))
+ var->err |= VARIANT_BAD_BRACKETING;
+
+ /* Check using of hidden symbols. */
+ if (var->hidden_by)
+ var->err |= VARIANT_HIDDEN;
+
+ if (!var->err)
+ {
+ valid_variant_index = i;
+ ++valid_variants;
+ }
+ }
+
+ switch (valid_variants)
+ {
+ case 0:
+ if (variant_count == 0)
+ {
+ if (explicit_bracketing || !ref_tail_fields)
+ complain_at (text_loc, _("unresolved reference: %s"),
+ quote(text));
+ else
+ {
+ unsigned len = ref_tail_fields - text;
+ char *str = strndup (text, len);
+ text_loc.end.column = text_loc.start.column + len;
+ complain_at (text_loc, _("unresolved reference: %s"),
+ quote (str));
+ free (str);
+ }
+ }
+ else
+ {
+ complain_at (text_loc, _("invalid reference: %s"),
+ quote (text));
+ show_sub_messages (cp, explicit_bracketing, midrule_rhs_index,
+ dollar_or_at, false);
+ }
+ return INVALID_REF;
+ case 1:
+ {
+ if (variant_count > 1)
+ {
+ warn_at (text_loc, _("misleading reference: %s"),
+ quote (text));
+ show_sub_messages (cp, explicit_bracketing, midrule_rhs_index,
+ dollar_or_at, true);
+ }
+ {
+ unsigned symbol_index =
+ variant_table[valid_variant_index].symbol_index;
+ return (symbol_index == midrule_rhs_index) ? LHS_REF : symbol_index;
+ }
+ }
+ case 2:
+ default:
+ complain_at (text_loc, _("ambiguous reference: %s"),
+ quote (text));
+ show_sub_messages (cp, explicit_bracketing, midrule_rhs_index,
+ dollar_or_at, false);
+ return INVALID_REF;
+ }
+
+ /* Not reachable. */
+ return INVALID_REF;
+}
+
projects / bison.git / blobdiff