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lalr1.cc: fix exception safety

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lalr1.cc does not reclaim its memory when ended by an exception.

Reported by Oleksii Taran:
http://lists.gnu.org/archive/html/help-bison/2012-09/msg00000.html

* data/lalr1.cc (yyparse): Protect the whole yyparse by a try-catch
block that cleans the stack and the lookahead.
This commit is contained in:
Akim Demaille
2012-09-20 16:59:29 +02:00
parent cff926615f
commit 7e1fabbeae
2 changed files with 39 additions and 7 deletions
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45
data/lalr1.cc
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@@ -533,6 +533,10 @@ do { \
int yyresult;
// FIXME: This shoud be completely indented. It is not yet to
// avoid gratuitous conflicts when merging into the master branch.
try
{
YYCDEBUG << "Starting parse" << std::endl;
]m4_ifdef([b4_initial_action], [
@@ -573,14 +577,13 @@ b4_dollar_popdef])[]dnl
/* Read a lookahead token. */
if (yychar == yyempty_)
{
YYCDEBUG << "Reading a token: ";
yychar = ]b4_c_function_call([yylex], [int],
[b4_api_PREFIX[STYPE*], [&yylval]][]dnl
YYCDEBUG << "Reading a token: ";
yychar = ]b4_c_function_call([yylex], [int],
[b4_api_PREFIX[STYPE*], [&yylval]][]dnl
b4_locations_if([, [[location*], [&yylloc]]])dnl
m4_ifdef([b4_lex_param], [, ]b4_lex_param))[;
}
/* Convert token to internal form. */
if (yychar <= yyeof_)
{
@@ -651,17 +654,21 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param))[;
else
yyval = yysemantic_stack_[0];
// Compute the default @@$.
{
slice<location_type, location_stack_type> slice (yylocation_stack_, yylen);
YYLLOC_DEFAULT (yyloc, slice, yylen);
}
// Perform the reduction.
YY_REDUCE_PRINT (yyn);
switch (yyn)
{
]b4_user_actions[
default:
break;
]b4_user_actions[
default:
break;
}
/* User semantic actions sometimes alter yychar, and that requires
that yytoken be updated with the new translation. We take the
approach of translating immediately before every use of yytoken.
@@ -831,6 +838,30 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param))[;
}
return yyresult;
}
catch (...)
{
YYCDEBUG << "Exception caught" << std::endl;
if (yychar != yyempty_)
{
/* Make sure we have latest lookahead translation. See
comments at user semantic actions for why this is
necessary. */
yytoken = yytranslate_ (yychar);
yydestruct_ ("Cleanup: discarding lookahead", yytoken, &yylval,
&yylloc);
}
while (yystate_stack_.height () != 1)
{
yydestruct_ ("Cleanup: popping",
yystos_[yystate_stack_[0]],
&yysemantic_stack_[0],
&yylocation_stack_[0]);
yypop_ ();
}
throw;
}
}
// Generate an error message.