Hi,
I've found out that Bison 3.0.4 parser crashes when you attempt to throw
syntax_error from any mid-rule action of C++ parser, which uses location
tracking. Here's a simple example:
%code provides {
int yylex(yy::parser::semantic_type* type, const yy::parser::location_type*
loc);
}
%require "3.0.4"
%language "C++"
%skeleton "lalr1.cc"
%locations
%define api.value.type {int}
%%
start:
'1' '2' '3' { throw syntax_error(@1, "Test"); } '4' '5' '6' { $$ = 0; }
;
%%
void yy::parser::error(const yy::parser::location_type& loc, const std::string&
message)
{
std::cout << message << std::endl;
}
int yylex(yy::parser::semantic_type* type, const yy::parser::location_type* loc)
{
static int start = '0';
return ++start;
}
int main()
{
yy::parser().parse();
}
The crash occurs in yyerrorlab, when trying to do something with locations, in
the following autogenerated line:
yyerror_range[1].location = yystack_[yylen - 1].location; // <- crash, as
yylen = 0 here
Fortunately, there's an easy workaround for this bug: it's possible to move
mid-rule action to another rule, and the issue doesn't reproduce anymore:
start:
one_two_three '4' '5' '6' { $$ = 0; }
;
one_two_three:
'1' '2' '3' { throw syntax_error(@1, "Test"); }
;
And a small another bug: it's currently not possible to use syntax_error class
from outside grammar file, as it has inline constructor defined (c++.m4), which
makes this class non-constructible from other cpp files, at least in Visual
Studio 2015. Removing "inline" keyword solves this issue.
