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Fix bug such that the first pushed token's value and location are

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sometimes overwritten (sometimes by %initial-action) before being used.
* data/push.c (yypush_parse): Rename arguments yynchar, yynlval, and
yynlloc to yypushed_char, yypushed_val, and yypushed_loc for clarity.
For the first yypush_parse invocation, initialize yychar to YYEMPTY to
more closely mimic the pull parser logic.
Don't copy the pushed token to yychar, yylval, and yylloc until it's
time to read a token, which is after any initialization of yylval and
yylloc.
(gottoken): Rename label to...
(yyread_pushed_token): ... for clarity and to avoid infringing on the
user namespace.
This commit is contained in:
Joel E. Denny
2006-12-20 06:46:20 +00:00
parent 9baf4d74a6
commit 8646b6a3fd
2 changed files with 48 additions and 32 deletions
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15
ChangeLog
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@@ -1,3 +1,18 @@
2006-12-20 Joel E. Denny <jdenny@ces.clemson.edu>
Fix bug such that the first pushed token's value and location are
sometimes overwritten (sometimes by %initial-action) before being used.
* data/push.c (yypush_parse): Rename arguments yynchar, yynlval, and
yynlloc to yypushed_char, yypushed_val, and yypushed_loc for clarity.
For the first yypush_parse invocation, initialize yychar to YYEMPTY to
more closely mimic the pull parser logic.
Don't copy the pushed token to yychar, yylval, and yylloc until it's
time to read a token, which is after any initialization of yylval and
yylloc.
(gottoken): Rename label to...
(yyread_pushed_token): ... for clarity and to avoid infringing on the
user namespace.
2006-12-20 Joel E. Denny <jdenny@ces.clemson.edu> 2006-12-20 Joel E. Denny <jdenny@ces.clemson.edu>
Rearrange initialization of the parser state variables so that the Rearrange initialization of the parser state variables so that the

65
data/push.c
View File

@@ -227,9 +227,9 @@ b4_c_function_decl([[yypstate_delete]], [[void]],
[[[yypstate *yyps]], [[yyps]]]) [[[yypstate *yyps]], [[yyps]]])
b4_c_function_decl([[yypush_parse]], [[int]], b4_c_function_decl([[yypush_parse]], [[int]],
[[[yypstate *yyps]], [[yyps]]], [[[yypstate *yyps]], [[yyps]]],
[[[int yynchar]], [[yynchar]]], [[[int yypushed_char]], [[yypushed_char]]],
[[[YYSTYPE const *yynlval]], [[yynlval]]]b4_locations_if([, [[[YYSTYPE const *yypushed_val]], [[yypushed_val]]]b4_locations_if([,
[[[YYLTYPE const *yynlloc]], [[yynlloc]]]])m4_ifset([b4_parse_param], [, [[[YYLTYPE const *yypushed_loc]], [[yypushed_loc]]]])m4_ifset([b4_parse_param], [,
b4_parse_param]))[ b4_parse_param]))[
#endif #endif
]]) ]])
@@ -1102,9 +1102,9 @@ b4_push_if(
]b4_push_if([ ]b4_push_if([
b4_c_function_def([[yypush_parse]], [[int]], [[[yypstate *yyps]], [[yyps]]], b4_c_function_def([[yypush_parse]], [[int]], [[[yypstate *yyps]], [[yyps]]],
[[[int yynchar]], [[yynchar]]], [[[int yypushed_char]], [[yypushed_char]]],
[[[YYSTYPE const *yynlval]], [[yynlval]]]b4_locations_if([, [[[YYSTYPE const *yypushed_val]], [[yypushed_val]]]b4_locations_if([,
[[[YYLTYPE const *yynlloc]], [[yynlloc]]]])m4_ifset([b4_parse_param], [, [[[YYLTYPE const *yypushed_loc]], [[yypushed_loc]]]])m4_ifset([b4_parse_param], [,
b4_parse_param]))], [ b4_parse_param]))], [
#ifdef YYPARSE_PARAM #ifdef YYPARSE_PARAM
b4_c_function_def([yyparse], [int], [[void *YYPARSE_PARAM], [YYPARSE_PARAM]]) b4_c_function_def([yyparse], [int], [[void *YYPARSE_PARAM], [YYPARSE_PARAM]])
@@ -1127,20 +1127,10 @@ b4_c_function_def([yyparse], [int], b4_parse_param)
/* The number of symbols on the RHS of the reduced rule. /* The number of symbols on the RHS of the reduced rule.
Keep to zero when no symbol should be popped. */ Keep to zero when no symbol should be popped. */
int yylen = 0; int yylen = 0;
]b4_push_if([ yychar = yynchar; ]b4_push_if([[
if (yynlval) if (!yyps->yynew)
yylval = *yynlval; goto yyread_pushed_token;
]b4_locations_if([ if (yynlloc) ]])[
yylloc = *yynlloc;])[],[yynerrs = 0;
yychar = YYEMPTY; /* Cause a token to be read. */])[
]b4_push_if([
if (yyps->yynew == 0)
{
goto gottoken;
}
yyps->yynew= 0;])[
yytoken = 0; yytoken = 0;
yyss = yyssa; yyss = yyssa;
yyvs = yyvsa; yyvs = yyvsa;
@@ -1152,6 +1142,8 @@ b4_c_function_def([yyparse], [int], b4_parse_param)
yystate = 0; yystate = 0;
yyerrstatus = 0; yyerrstatus = 0;
]b4_push_if([], [[ yynerrs = 0;]])[
yychar = YYEMPTY; /* Cause a token to be read. */
/* Initialize stack pointers. /* Initialize stack pointers.
Waste one element of value and location stack Waste one element of value and location stack
@@ -1170,7 +1162,7 @@ b4_c_function_def([yyparse], [int], b4_parse_param)
m4_ifdef([b4_initial_action], [ m4_ifdef([b4_initial_action], [
m4_pushdef([b4_at_dollar], [m4_define([b4_at_dollar_used])yylloc])dnl m4_pushdef([b4_at_dollar], [m4_define([b4_at_dollar_used])yylloc])dnl
m4_pushdef([b4_dollar_dollar], [m4_define([b4_dollar_dollar_used])yylval])dnl m4_pushdef([b4_dollar_dollar], [m4_define([b4_dollar_dollar_used])yylval])dnl
/* User initialization code. */ /* User initialization code. */
b4_user_initial_action b4_user_initial_action
m4_popdef([b4_dollar_dollar])dnl m4_popdef([b4_dollar_dollar])dnl
m4_popdef([b4_at_dollar])])dnl m4_popdef([b4_at_dollar])])dnl
@@ -1282,14 +1274,23 @@ yybackup:
/* YYCHAR is either YYEMPTY or YYEOF or a valid lookahead symbol. */ /* YYCHAR is either YYEMPTY or YYEOF or a valid lookahead symbol. */
if (yychar == YYEMPTY) if (yychar == YYEMPTY)
{ {
]b4_push_if([ ]b4_push_if([[ if (!yyps->yynew)
YYDPRINTF ((stderr, "Return for a new token:\n")); {
yyresult = YYPUSH_MORE; YYDPRINTF ((stderr, "Return for a new token:\n"));
goto yypushreturn; yyresult = YYPUSH_MORE;
gottoken:])[ goto yypushreturn;
YYDPRINTF ((stderr, "Reading a token: ")); }
]b4_push_if([], [yychar = YYLEX;])[ yyps->yynew = 0;
}
yyread_pushed_token:
]])[ YYDPRINTF ((stderr, "Reading a token: "));
]b4_push_if([[ yychar = yypushed_char;
if (yypushed_val)
yylval = *yypushed_val;
]b4_locations_if([[ if (yypushed_loc)
yylloc = *yypushed_loc;]])],
[[ yychar = YYLEX;
]])[ }
if (yychar <= YYEOF) if (yychar <= YYEOF)
{ {
@@ -1640,9 +1641,9 @@ b4_c_function_decl([b4_prefix[pstate_delete]], [[void]],
[[b4_prefix[pstate *yyps]], [[yyps]]]) [[b4_prefix[pstate *yyps]], [[yyps]]])
b4_c_function_decl([b4_prefix[push_parse]], [[int]], b4_c_function_decl([b4_prefix[push_parse]], [[int]],
[[b4_prefix[pstate *yyps]], [[yyps]]], [[b4_prefix[pstate *yyps]], [[yyps]]],
[[[int yynchar]], [[yynchar]]], [[[int yypushed_char]], [[yypushed_char]]],
[[[YYSTYPE const *yynlval]], [[yynlval]]]b4_locations_if([, [[[YYSTYPE const *yypushed_val]], [[yypushed_val]]]b4_locations_if([,
[[[YYLTYPE const *yynlloc]], [[yynlloc]]]])m4_ifset([b4_parse_param], [, [[[YYLTYPE const *yypushed_loc]], [[yypushed_loc]]]])m4_ifset([b4_parse_param], [,
b4_parse_param]))[ b4_parse_param]))[
#endif #endif
]]) ]])