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YYACCEPT, YYERROR, and YYABORT, as user actions, should not

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destroy the RHS symbols of a rule.
* data/yacc.c (yylen): Initialize to 0.
Keep its value to the number of items to possibly shift.
In particular, a regular successful parse that ends on YYFINAL by
a (internal) YYACCEPT must not have yylen != 0.
(yyerrorlab, yyreturn): Pop the RHS.
Reorder a bit to emphasize the `shifting' bits of code.
(YYPOPSTACK): Now accept a number of items to pop.
* data/lalr1.cc: Likewise.
* data/glr.c: Formatting changes.
Use goto instead of fall through.
* doc/bison.texinfo (Destructor Decl): Complete.
This commit is contained in:
Akim Demaille
2005-12-21 15:28:30 +00:00
parent e14d0ab687
commit a85284cfbd
6 changed files with 89 additions and 79 deletions
Download Patch File Download Diff File Expand all files Collapse all files

16
data/glr.c
View File

@@ -909,10 +909,12 @@ yyuserAction (yyRuleNum yyn, int yyrhslen, yyGLRStackItem* yyvsp,
*yyvalp = yyvsp[YYFILL (1-yyrhslen)].yystate.yysemantics.yysval;
YYLLOC_DEFAULT (*yylocp, yyvsp - yyrhslen, yyrhslen);
]b4_location_if([[ yystackp->yyerror_range[1].yystate.yyloc = *yylocp;
]])
]])[
switch (yyn)
{
b4_actions
]b4_actions
/* Line __line__ of glr.c. */
b4_syncline([@oline@], [@ofile@])[
default: break;
}
@@ -924,8 +926,6 @@ yyuserAction (yyRuleNum yyn, int yyrhslen, yyGLRStackItem* yyvsp,
# undef YYBACKUP
# undef yyclearin
# undef YYRECOVERING
/* Line __line__ of glr.c. */
b4_syncline([@oline@], [@ofile@])
}
@@ -937,11 +937,11 @@ yyuserMerge (int yyn, YYSTYPE* yy0, YYSTYPE* yy1)
switch (yyn)
{
b4_mergers
]b4_mergers[
default: break;
}
}
[
/* Bison grammar-table manipulation. */
]b4_yydestruct_generate([b4_c_ansi_function_def])[
@@ -2324,7 +2324,7 @@ b4_syncline([@oline@], [@ofile@])])dnl
yybuglab:
YYASSERT (yyfalse);
/* Fall through. */
goto yyabortlab;
yyabortlab:
yyresult = 1;
@@ -2333,7 +2333,7 @@ b4_syncline([@oline@], [@ofile@])])dnl
yyexhaustedlab:
yyerror (]b4_lyyerror_args[YY_("memory exhausted"));
yyresult = 2;
/* Fall through. */
goto yyreturn;
yyreturn:
if (yytoken != YYEOF && yytoken != YYEMPTY)

18
data/lalr1.cc
View File

@@ -509,7 +509,7 @@ namespace yy
/* State. */
int yyn;
int yylen;
int yylen = 0;
int yystate = 0;
/* Error handling. */
@@ -641,7 +641,7 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param))[;
`-----------------------------*/
yyreduce:
yylen = yyr2_[yyn];
/* If LEN_ is nonzero, implement the default value of the action:
/* If YYLEN is nonzero, implement the default value of the action:
`$$ = $1'. Otherwise, use the top of the stack.
Otherwise, the following line sets YYVAL to garbage.
@@ -659,15 +659,15 @@ m4_ifdef([b4_lex_param], [, ]b4_lex_param))[;
YY_REDUCE_PRINT (yyn);
switch (yyn)
{
]b4_actions[
]b4_actions
/* Line __line__ of lalr1.cc. */
b4_syncline([@oline@], [@ofile@])[
default: break;
}
YY_SYMBOL_PRINT ("-> $$ =", yyr1_[yyn], &yyval, &yyloc);
/* Line __line__ of lalr1.cc. */
]b4_syncline([@oline@], [@ofile@])[
yypop_ (yylen);
yylen = 0;
YY_STACK_PRINT ();
yysemantic_stack_.push (yyval);
@@ -731,7 +731,10 @@ b4_error_verbose_if([, yytoken])[));
goto yyerrorlab;
yyerror_range[0] = yylocation_stack_[yylen - 1];
/* Do not reclaim the symbols of the rule which action triggered
this YYERROR. */
yypop_ (yylen);
yylen = 0;
yystate = yystate_stack_[0];
goto yyerrlab1;
@@ -799,6 +802,9 @@ b4_error_verbose_if([, yytoken])[));
if (yychar != yyeof_ && yychar != yyempty_)
yydestruct_ ("Cleanup: discarding lookahead", yytoken, &yylval, &yylloc);
/* Do not reclaim the symbols of the rule which action triggered
this YYABORT or YYACCEPT. */
yypop_ (yylen);
while (yystate_stack_.height () != 1)
{
yydestruct_ ("Cleanup: popping",

64
data/yacc.c
View File

@@ -564,7 +564,7 @@ do \
yychar = (Token); \
yylval = (Value); \
yytoken = YYTRANSLATE (yychar); \
YYPOPSTACK; \
YYPOPSTACK (1); \
goto yybackup; \
} \
else \
@@ -1042,7 +1042,7 @@ b4_c_function_def([yyparse], [int], b4_parse_param)
/* The locations where the error started and ended. */
YYLTYPE yyerror_range[2];]])[
#define YYPOPSTACK (yyvsp--, yyssp--]b4_location_if([, yylsp--])[)
#define YYPOPSTACK(N) (yyvsp -= (N), yyssp -= (N)]b4_location_if([, yylsp -= (N)])[)
YYSIZE_T yystacksize = YYINITDEPTH;
@@ -1051,9 +1051,9 @@ b4_c_function_def([yyparse], [int], b4_parse_param)
YYSTYPE yyval;
]b4_location_if([ YYLTYPE yyloc;])[
/* When reducing, the number of symbols on the RHS of the reduced
rule. */
int yylen;
/* The number of symbols on the RHS of the reduced rule.
Keep to zero when no symbol should be popped off. */
int yylen = 0;
YYDPRINTF ((stderr, "Starting parse\n"));
@@ -1178,12 +1178,10 @@ m4_ifdef([b4_at_dollar_used], [[ yylsp[0] = yylloc;
`-----------*/
yybackup:
/* Do appropriate processing given the current state. */
/* Read a look-ahead token if we need one and don't already have one. */
/* yyresume: */
/* Do appropriate processing given the current state. Read a
look-ahead token if we need one and don't already have one. */
/* First try to decide what to do without reference to look-ahead token. */
yyn = yypact[yystate];
if (yyn == YYPACT_NINF)
goto yydefault;
@@ -1225,22 +1223,21 @@ yybackup:
if (yyn == YYFINAL)
YYACCEPT;
/* Shift the look-ahead token. */
YY_SYMBOL_PRINT ("Shifting", yytoken, &yylval, &yylloc);
/* Discard the token being shifted unless it is eof. */
if (yychar != YYEOF)
yychar = YYEMPTY;
*++yyvsp = yylval;
]b4_location_if([ *++yylsp = yylloc;])[
/* Count tokens shifted since error; after three, turn off error
status. */
if (yyerrstatus)
yyerrstatus--;
/* Shift the look-ahead token. */
YY_SYMBOL_PRINT ("Shifting", yytoken, &yylval, &yylloc);
/* Discard the shifted token unless it is eof. */
if (yychar != YYEOF)
yychar = YYEMPTY;
yystate = yyn;
*++yyvsp = yylval;
]b4_location_if([ *++yylsp = yylloc;])[
goto yynewstate;
@@ -1277,18 +1274,15 @@ yyreduce:
YY_REDUCE_PRINT (yyn);
switch (yyn)
{
]b4_actions[
]b4_actions
/* Line __line__ of yacc.c. */
b4_syncline([@oline@], [@ofile@])[
default: break;
}
YY_SYMBOL_PRINT ("-> $$ =", yyr1[yyn], &yyval, &yyloc);
/* Line __line__ of yacc.c. */
]b4_syncline([@oline@], [@ofile@])[
yyvsp -= yylen;
yyssp -= yylen;
]b4_location_if([ yylsp -= yylen;])[
YYPOPSTACK (yylen);
yylen = 0;
YY_STACK_PRINT (yyss, yyssp);
*++yyvsp = yyval;
@@ -1392,9 +1386,11 @@ yyerrorlab:
goto yyerrorlab;
]b4_location_if([[ yyerror_range[0] = yylsp[1-yylen];
yylsp -= yylen;
]])[yyvsp -= yylen;
yyssp -= yylen;
]])[ /* Do not reclaim the symbols of the rule which action triggered
this YYERROR. */
YYPOPSTACK (yylen);
yylen = 0;
YY_STACK_PRINT (yyss, yyssp);
yystate = *yyssp;
goto yyerrlab1;
@@ -1426,7 +1422,7 @@ yyerrlab1:
]b4_location_if([[ yyerror_range[0] = *yylsp;]])[
yydestruct ("Error: popping",
yystos[yystate], yyvsp]b4_location_if([, yylsp])[]b4_user_args[);
YYPOPSTACK;
YYPOPSTACK (1);
yystate = *yyssp;
YY_STACK_PRINT (yyss, yyssp);
}
@@ -1477,11 +1473,15 @@ yyreturn:
if (yychar != YYEOF && yychar != YYEMPTY)
yydestruct ("Cleanup: discarding lookahead",
yytoken, &yylval]b4_location_if([, &yylloc])[]b4_user_args[);
/* Do not reclaim the symbols of the rule which action triggered
this YYABORT or YYACCEPT. */
YYPOPSTACK (yylen);
YY_STACK_PRINT (yyss, yyssp);
while (yyssp != yyss)
{
yydestruct ("Cleanup: popping",
yystos[*yyssp], yyvsp]b4_location_if([, yylsp])[]b4_user_args[);
YYPOPSTACK;
YYPOPSTACK (1);
}
#ifndef yyoverflow
if (yyss != yyssa)