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lalr1, yacc: use the default location as initial error location

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Currently lalr1.cc makes an out-of-bound access when trying to read @1
in rules with an empty rhs (i.e., when there is no @1) that raises an
error (YYERROR).

glr.c already gracefully handles this by using @$ as initial location
for the errors.  Let's do that in yacc.c and lalr1.cc.

* data/lalr1.cc, data/yacc.c: Use @$ to initialize the error location.
* tests/actions.at: Check that case.
This commit is contained in:
Akim Demaille
2015-08-11 13:48:57 +02:00
parent 55fb68aabf
commit 476c1cca59
4 changed files with 97 additions and 12 deletions
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4
data/lalr1.cc
View File

@@ -848,6 +848,7 @@ b4_dollar_popdef])[]dnl
{
slice<stack_symbol_type, stack_type> slice (yystack_, yylen);
YYLLOC_DEFAULT (yylhs.location, slice, yylen);
yyerror_range[1].location = yylhs.location;
}]])[
// Perform the reduction.
@@ -918,8 +919,7 @@ b4_dollar_popdef])[]dnl
YYERROR and the label yyerrorlab therefore never appears in user
code. */
if (false)
goto yyerrorlab;]b4_locations_if([[
yyerror_range[1].location = yystack_[yylen - 1].location;]])[
goto yyerrorlab;
/* Do not reclaim the symbols of the rule whose action triggered
this YYERROR. */
yypop_ (yylen);

8
data/yacc.c
View File

@@ -1641,8 +1641,9 @@ yyreduce:
yyval = yyvsp[1-yylen];
]b4_locations_if(
[[ /* Default location. */
YYLLOC_DEFAULT (yyloc, (yylsp - yylen), yylen);]])[
[[ /* Default location. */
YYLLOC_DEFAULT (yyloc, (yylsp - yylen), yylen);
yyerror_range[1] = yyloc;]])[
YY_REDUCE_PRINT (yyn);]b4_lac_if([[
{
int yychar_backup = yychar;
@@ -1782,8 +1783,7 @@ yyerrorlab:
if (/*CONSTCOND*/ 0)
goto yyerrorlab;
]b4_locations_if([[ yyerror_range[1] = yylsp[1-yylen];
]])[ /* Do not reclaim the symbols of the rule whose action triggered
/* Do not reclaim the symbols of the rule whose action triggered
this YYERROR. */
YYPOPSTACK (yylen);
yylen = 0;