diff options
| -rw-r--r-- | perly.c | 56 |
1 files changed, 53 insertions, 3 deletions
@@ -245,6 +245,38 @@ yystpcpy (pTHX_ char *yydest, const char *yysrc) #endif /* !YYERROR_VERBOSE */ + +/* a snapshot of the current stack position variables for use by + * S_clear_yystack */ + +typedef struct { + short *yyss; + short *yyssp; + YYSTYPE *yyvsp; + int yylen; +} yystack_positions; + +/* called during cleanup (via SAVEDESTRUCTOR_X) to free any items on the + * parse stack, thus avoiding leaks if we die */ + +static void +S_clear_yystack(pTHX_ const void *p) +{ + yystack_positions *y = (yystack_positions*) p; + + if (!y->yyss) + return; + YYDPRINTF ((Perl_debug_log, "clearing the parse stack\n")); + y->yyvsp -= y->yylen; /* ignore the tokens that have just been reduced */ + y->yyssp -= y->yylen; + while (y->yyssp > y->yyss) { + if (yy_is_opval[yystos[*y->yyssp]]) + op_free(y->yyvsp->opval); + y->yyvsp--; + y->yyssp--; + } +} + /*----------. | yyparse. | `----------*/ @@ -283,6 +315,8 @@ Perl_yyparse (pTHX) /* for ease of re-allocation and automatic freeing, have two SVs whose * SvPVX points to the stacks */ SV *yyss_sv, *yyvs_sv; + SV *ss_save_sv; + yystack_positions *ss_save; #ifdef DEBUGGING /* maintain also a stack of token/rule names for debugging with -Dpv */ @@ -320,10 +354,18 @@ Perl_yyparse (pTHX) yyss_sv = newSV(YYINITDEPTH * sizeof(short)); yyvs_sv = newSV(YYINITDEPTH * sizeof(YYSTYPE)); + ss_save_sv = newSV(sizeof(yystack_positions)); SAVEFREESV(yyss_sv); SAVEFREESV(yyvs_sv); + SAVEFREESV(ss_save_sv); yyss = (short *) SvPVX(yyss_sv); yyvs = (YYSTYPE *) SvPVX(yyvs_sv); + ss_save = (yystack_positions *) SvPVX(ss_save_sv); + + ss_save->yyss = NULL; /* disarm stack cleanup */ + /* cleanup the parse stack on premature exit */ + SAVEDESTRUCTOR_X(S_clear_yystack, (void*) ss_save); + /* note that elements zero of yyvs and yyns are not used */ yyssp = yyss; yyvsp = yyvs; @@ -340,8 +382,6 @@ Perl_yyparse (pTHX) yynerrs = 0; yychar = YYEMPTY; /* Cause a token to be read. */ - - YYDPRINTF ((Perl_debug_log, "Entering state %d\n", yystate)); goto yysetstate; @@ -507,6 +547,15 @@ Perl_yyparse (pTHX) YY_REDUCE_PRINT (yyn); + + /* running external code may trigger a die (eg 'use nosuchmodule'): + * record the current stack state so that an unwind will + * free all the pesky OPs lounging around on the parse stack */ + ss_save->yyss = yyss; + ss_save->yyssp = yyssp; + ss_save->yyvsp = yyvsp; + ss_save->yylen = yylen; + switch (yyn) { /* contains all the rule actions; auto-generated from perly.y */ @@ -716,7 +765,8 @@ Perl_yyparse (pTHX) yyreturn: - LEAVE; /* force stack free before we return */ + ss_save->yyss = NULL; /* disarm parse stack cleanup */ + LEAVE; /* force stack free before we return */ return yyresult; } |