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named references: fix double free.

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In `rhs[name]: "a" | "b"', do not free "name" twice.
Reported by Tys Lefering.
<http://lists.gnu.org/archive/html/bug-bison/2010-06/msg00002.html>

	* src/named-ref.h, src/named-ref.c (named_ref_copy): New.
	* src/parse-gram.y (current_lhs): Rename as...
	(current_lhs_symbol): this.
	(current_lhs): New function.  Use it to free the current lhs
	named reference.
	* src/reader.c: Bind lhs to a copy of the current named reference.
	* src/symlist.c: Rely on free (0) being valid.
	* tests/named-refs.at: Test this.

(cherry picked from commit 8f462efe92)

Conflicts:

	src/parse-gram.y
This commit is contained in:
Akim Demaille
2011-03-09 21:10:35 +01:00
parent 17d7bf83d0
commit a4d1bf6a9c
8 changed files with 65 additions and 8 deletions
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29
src/parse-gram.y
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@@ -56,10 +56,28 @@ static char const *char_name (char);
static int current_prec = 0;
static location current_lhs_location;
static named_ref *current_lhs_named_ref;
static symbol *current_lhs;
static symbol *current_lhs_symbol;
static symbol_class current_class = unknown_sym;
static uniqstr current_type = NULL;
/** Set the new current left-hand side symbol, possibly common
* to several right-hand side parts of rule.
*/
static
void
current_lhs(symbol *sym, location loc, named_ref *ref)
{
current_lhs_symbol = sym;
current_lhs_location = loc;
/* In order to simplify memory management, named references for lhs
are always assigned by deep copy into the current symbol_list
node. This is because a single named-ref in the grammar may
result in several uses when the user factors lhs between several
rules using "|". Therefore free the parser's original copy. */
free (current_lhs_named_ref);
current_lhs_named_ref = ref;
}
#define YYTYPE_INT16 int_fast16_t
#define YYTYPE_INT8 int_fast8_t
#define YYTYPE_UINT16 uint_fast16_t
@@ -569,8 +587,11 @@ rules_or_grammar_declaration:
;
rules:
id_colon named_ref.opt { current_lhs = $1; current_lhs_location = @1;
current_lhs_named_ref = $2; } rhses.1
id_colon named_ref.opt { current_lhs ($1, @1, $2); } rhses.1
{
/* Free the current lhs. */
current_lhs (0, @1, 0);
}
;
rhses.1:
@@ -581,7 +602,7 @@ rhses.1:
rhs:
/* Nothing. */
{ grammar_current_rule_begin (current_lhs, current_lhs_location,
{ grammar_current_rule_begin (current_lhs_symbol, current_lhs_location,
current_lhs_named_ref); }
| rhs symbol named_ref.opt
{ grammar_current_rule_symbol_append ($2, @2, $3); }