+2006-01-29 Paul Eggert <eggert@cs.ucla.edu>
+
+ Fix a longstanding bug uncovered by bro-0.9a9/src/parse.y, which I
+ got from <http://bro-ids.org/download.html>. The bug is that
+ when two actions appeared in succession, the second one was
+ scanned before the first one was added to the grammar rule
+ as a midrule action. Bison then output the incorrect warning
+ "parse.y:905.17-906.36: warning: unused value: $3".
+ * src/parse-gram.y (BRACED_CODE, action): These are no longer
+ associated with a value.
+ (rhs): Don't invoke grammar_current_rule_action_append.
+ (action): Invoke it here instead.
+ * src/reader.c (grammar_midrule_action): Now extern.
+ (grammar_current_rule_action_append): Don't invoke
+ grammar_midrule_action; that is now the scanner's job.
+ * src/reader.h (last_string, last_braced_code_loc):
+ (grammar_midrule_action): New decls.
+ * src/scan-gram.l (last_string): Now extern, sigh.
+ (last_braced_code_loc): New extern variable.
+ (<INITIAL>"{"): Invoke grammar_midrule_action if the current
+ rule already has an action.
+ (<SC_BRACED_CODE>"}"): Set last_braced_code_loc before returning.
+ * tests/input.at (AT_CHECK_UNUSED_VALUES):
+ Add some tests to check that the above changes fixed the bug.
+
2006-01-27 Paul Eggert <eggert@cs.ucla.edu>
* src/reader.c (symbol_should_be_used): Renamed from symbol_typed_p.
"%parse-param {...}"
"%printer {...}"
"%union {...}"
- BRACED_CODE action
PROLOGUE EPILOGUE
%printer { fprintf (stderr, "\"%s\"", $$); }
STRING string_content
"%parse-param {...}"
"%printer {...}"
"%union {...}"
- BRACED_CODE action
PROLOGUE EPILOGUE
%type <uniqstr> TYPE
%printer { fprintf (stderr, "<%s>", $$); } TYPE
| rhs symbol
{ grammar_current_rule_symbol_append ($2, @2); }
| rhs action
- { grammar_current_rule_action_append ($2, @2); }
| rhs "%prec" symbol
{ grammar_current_rule_prec_set ($3, @3); }
| rhs "%dprec" INT
| string_as_id { $$ = $1; }
;
+/* Handle the semantics of an action specially, with a mid-rule
+ action, so that grammar_current_rule_action_append is invoked
+ immediately after the braced code is read by the scanner.
+
+ This implementation relies on the LALR(1) parsing algorithm.
+ If grammar_current_rule_action_append were executed in a normal
+ action for this rule, then when the input grammar contains two
+ successive actions, the scanner would have to read both actions
+ before reducing this rule. That wouldn't work, since the scanner
+ relies on all preceding input actions being processed by
+ grammar_current_rule_action_append before it scans the next
+ action. */
action:
+ { grammar_current_rule_action_append (last_string, last_braced_code_loc); }
BRACED_CODE
- { $$ = $1; }
;
/* A string used as an ID: quote it. */
| rule. |
`-------------------------------------------------------------------*/
-static void
+void
grammar_midrule_action (void)
{
/* Since the action was written out with this rule's number, we must
grammar_symbol_append (sym, loc);
}
-/* Attach an ACTION to the current rule. If needed, move the previous
- action as a mid-rule action. */
+/* Attach an ACTION to the current rule. */
void
grammar_current_rule_action_append (const char *action, location loc)
{
- if (current_rule->action)
- grammar_midrule_action ();
+ /* There's no need to invoke grammar_midrule_action here, since the
+ scanner already did it if necessary. */
current_rule->action = action;
current_rule->action_location = loc;
}
/* Input parser for Bison
- Copyright (C) 2000, 2001, 2002, 2003, 2005 Free Software Foundation, Inc.
+ Copyright (C) 2000, 2001, 2002, 2003, 2005, 2006 Free Software
+ Foundation, Inc.
This file is part of Bison, the GNU Compiler Compiler.
extern FILE *gram_in;
extern int gram__flex_debug;
extern boundary scanner_cursor;
+extern char *last_string;
+extern location last_braced_code_loc;
extern int max_left_semantic_context;
void scanner_initialize (void);
void scanner_free (void);
void prologue_augment (const char *prologue, location loc);
void grammar_current_rule_begin (symbol *lhs, location loc);
void grammar_current_rule_end (location loc);
+void grammar_midrule_action (void);
void grammar_current_rule_prec_set (symbol *precsym, location loc);
void grammar_current_rule_dprec_set (int dprec, location loc);
void grammar_current_rule_merge_set (uniqstr name, location loc);
static struct obstack obstack_for_string;
/* A string representing the most recently saved token. */
-static char *last_string;
+char *last_string;
+/* The location of the most recently saved token, if it was a
+ BRACED_CODE token; otherwise, this has an unspecified value. */
+location last_braced_code_loc;
#define STRING_GROW \
obstack_grow (&obstack_for_string, yytext, yyleng)
/* Code in between braces. */
"{" {
+ if (current_rule->action)
+ grammar_midrule_action ();
STRING_GROW;
token_type = BRACED_CODE;
braces_level = 0;
loc->start = code_start;
val->chars = last_string;
increment_rule_length (*loc);
+ last_braced_code_loc = *loc;
BEGIN INITIAL;
return token_type;
}
input.y:6.3-36: warning: unused value: $5
])
-# AT_CHECK_UNUSED_VALUES([INT { $$ } { $$ = $2 } { }],
-# [input.y:6.3-36: warning: unset value: $$
-# input.y:6.3-36: warning: unused value: $1
-# input.y:6.3-36: warning: unused value: $3
-# input.y:6.3-36: warning: unused value: $4
-# input.y:6.3-36: warning: unused value: $5
-# ])
-
-AT_CHECK_UNUSED_VALUES([INT { $$ = $1 } INT { $$ = $2 + $3 } INT { $$ = $4 + $5 }])
+AT_CHECK_UNUSED_VALUES([INT INT { } { $$ = $1 + $2; }])
+
+AT_CHECK_UNUSED_VALUES([INT INT { $<integer>$ = 1; } { $$ = $1 + $2; }],
+[input.y:6.3-48: warning: unused value: $3
+])
+
+AT_CHECK_UNUSED_VALUES([INT INT { $$; } { $$ = $3; } { }],
+[input.y:6.3-34: warning: unset value: $$
+input.y:6.3-34: warning: unused value: $1
+input.y:6.3-34: warning: unused value: $2
+input.y:6.3-34: warning: unused value: $4
+])
+
+AT_CHECK_UNUSED_VALUES(
+ [INT { $$ = $1; } INT { $$ = $2 + $3; } INT { $$ = $4 + $5; }])
projects / bison.git / commitdiff
