On 8/16/16, xiaobing <jingxiaob...@gmail.com> wrote:
> In lemon.c:ReportTable() , when " Combine duplicate destructors into a
> single case ", sp2->destructor is set to 0, but later it is used in
> tranlate_code to generate destructor.
> so if you have grammar like this:
> %destructor expr_a { expr_free($$); }
> %destructor expr_b { expr_free($$); } // this one will be lost, unless
> you insert some comment so strcmp return nonzero
> expr ::= expr_a expr_b.
> the generated code will include destructor of expr_a, however, destructor
> of expr_b will be lost.
Excellent analysis, Xiaobing. Thanks.
I have checked in a slightly different fix. Please confirm that what
I have checked in actually fixes your problem.
https://www.sqlite.org/src/fdiff?dc=20&v1=e3aa9ba3469804d7&v2=e4fb7d888873ac88
>
> Here is my patch to lemon.c:
>
> --- old/lemon.c 2016-05-18 18:07:00.000000000 +0800
> +++ new/lemon.c 2016-08-16 20:57:36.799178091 +0800
> @@ -263,6 +263,7 @@
> int useCnt; /* Number of times used */
> char *destructor; /* Code which executes whenever this symbol is
> ** popped from the stack during error
> processing */
> + int destructor_emitted; /* Is the destructor code emitted */
> int destLineno; /* Line number for start of destructor */
> char *datatype; /* The data type of information held by this
> ** object. Only used if type==NONTERMINAL */
> @@ -4351,8 +4352,9 @@
> }
> for(i=0; i<lemp->nsymbol; i++){
> struct symbol *sp = lemp->symbols[i];
> - if( sp==0 || sp->type==TERMINAL || sp->destructor==0 ) continue;
> + if( sp==0 || sp->type==TERMINAL || sp->destructor==0 ||
> sp->destructor_emitted) continue;
> fprintf(out," case %d: /* %s */\n", sp->index, sp->name); lineno++;
> + sp->destructor_emitted = 1;
>
> /* Combine duplicate destructors into a single case */
> for(j=i+1; j<lemp->nsymbol; j++){
> @@ -4362,7 +4364,7 @@
> && strcmp(sp->destructor,sp2->destructor)==0 ){
> fprintf(out," case %d: /* %s */\n",
> sp2->index, sp2->name); lineno++;
> - sp2->destructor = 0;
> + sp2->destructor_emitted = 1;
> }
> }
>
> @@ -4876,6 +4878,7 @@
> sp->firstset = 0;
> sp->lambda = LEMON_FALSE;
> sp->destructor = 0;
> + sp->destructor_emitted = 0;
> sp->destLineno = 0;
> sp->datatype = 0;
> sp->useCnt = 0;
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>
--
D. Richard Hipp
d...@sqlite.org
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