From 7c69854e2ad09fa16153e9d21c5512f3c21ecece Mon Sep 17 00:00:00 2001 From: Akim Demaille Date: Thu, 20 Sep 2012 16:59:29 +0200 Subject: [PATCH 3/3] lalr1.cc: fix exception safety 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 calls to yylex by a try-catch block that cleans the stack, but not the lookahead, as we can't even know its type (since yylex did not return, its token type is unknown). Protect user actions by a similar block that does reclaim the lookahead. --- THANKS | 1 + data/lalr1.cc | 62 +++++++++++++++++++++++++++++++++++++++++++++++++---------- 2 files changed, 53 insertions(+), 10 deletions(-) diff --git a/THANKS b/THANKS index 95acb1e..ee9ff66 100644 --- a/THANKS +++ b/THANKS @@ -80,6 +80,7 @@ Nicolas Tisserand nicolas.tisserand@epita.fr Noah Friedman friedman@gnu.org Odd Arild Olsen oao@fibula.no Oleg Smolsky oleg.smolsky@pacific-simulators.co.nz +Oleksii Taran oleksii.taran@gmail.com Paolo Bonzini bonzini@gnu.org Pascal Bart pascal.bart@epita.fr Paul Eggert eggert@cs.ucla.edu diff --git a/data/lalr1.cc b/data/lalr1.cc index 7456f6b..874666d 100644 --- a/data/lalr1.cc +++ b/data/lalr1.cc @@ -572,14 +572,27 @@ 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 + try + { + 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))[; - } - + } + catch (...) + { + YYCDEBUG << "Exception caught" << std::endl; + while (yystate_stack_.height () != 1) + { + yydestruct_ ("Cleanup: popping", + yystos_[yystate_stack_[0]], + &yysemantic_stack_[0], + &yylocation_stack_[0]); + yypop_ (); + } + throw; + } /* Convert token to internal form. */ if (yychar <= yyeof_) @@ -651,16 +664,45 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param))[; else yyval = yysemantic_stack_[0]; + // Compute the default @@$. { slice slice (yylocation_stack_, yylen); YYLLOC_DEFAULT (yyloc, slice, yylen); } + + // Perform the reduction. YY_REDUCE_PRINT (yyn); - switch (yyn) + try { - ]b4_user_actions[ - default: - break; + switch (yyn) + { + ]b4_user_actions[ + default: + break; + } + } + 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; } /* User semantic actions sometimes alter yychar, and that requires that yytoken be updated with the new translation. We take the -- 1.7.12.1