On these tests, at -O2 and above, GCC 8 complains that yylval may be
uninitialized. But it seems wrong: it is initialized. Rather than
turning off the warning in the skeleton (hence possibility hiding
relevant warnings of user parsers), let's turn it off in the tests
only.
163: parse.error=verbose and consistent errors: FAILED (conflicts.at:625)
165: parse.error=verbose and consistent errors: lr.default-reduction=consistent FAILED (conflicts.at:635)
166: parse.error=verbose and consistent errors: lr.default-reduction=accepting FAILED (conflicts.at:641)
167: parse.error=verbose and consistent errors: lr.type=canonical-lr FAILED (conflicts.at:645)
168: parse.error=verbose and consistent errors: parse.lac=full FAILED (conflicts.at:650)
169: parse.error=verbose and consistent errors: parse.lac=full lr.default-reduction=accepting FAILED (conflicts.at:655)
We get:
input.c: In function 'yyparse':
input.c:980:9: error: 'yylval' may be used uninitialized in this function [-Werror=maybe-uninitialized]
YYSTYPE yylval YY_INITIAL_VALUE (= yyval_default);
^~~~~~
cc1: all warnings being treated as errors
See https://lists.gnu.org/archive/html/bison-patches/2018-08/msg00063.html.
* tests/conflicts.at (AT_CONSISTENT_ERRORS_CHECK): Disable
-Wmaybe-uninitialized.
Suggested by Rici Lake.
https://lists.gnu.org/archive/html/bug-bison/2018-08/msg00033.html
* doc/bison.texi: Complete description of the first node in the main
@menu.
(Push Decl): Remove the 'experimental' warnings about push parser.
Clarify that the push parser object can be reused in several parses.
Reported by Brooks Moses <bmoses@google.com>
http://lists.gnu.org/archive/html/bison-patches/2018-02/msg00000.html
* data/lalr1.cc (YY_EXCEPTIONS): New.
Use it to disable try/catch clauses.
* doc/bison.texi (C++ Parser Interface): Document it.
* configure.ac (CXXFLAGS_NO_EXCEPTIONS): New.
* tests/atlocal.in: Receive it.
* tests/local.at (AT_FULL_COMPILE, AT_LANG_COMPILE):
Accept a new argument, extra compiler flags.
* tests/calc.at: Run the C++ calculator with exception support disabled.
Currently the examples are too dense, let's put empty lines where
'#line' would be issued. And also remove some spurious empty
lines (remains from @group, @end group, etc.).
* examples/extexi: Do that.
* examples/local.mk (extexiFLAGS): Rename as...
(EXTEXIFLAGS): this.
* examples/mfcalc/local.mk, examples/rpcalc/local.mk: Define the
programs in a more natural order, source, preproc, then linker.
* examples/test: Be ready to work on programs that are not in
a subdir.
* examples/variant.test: New.
* examples/local.mk: Use it.
* examples/variant.yy: Don't use 0 for nullptr.
Use a more natural output for a list of string.
Visual Studio issues a C4146 warning on '-static_cast<unsigned>(rhs)'.
The code is weird, probably to cope with INT_MIN. Let's go back to
using std::max (whose header is still included in position.hh...) like
originally, but with the needed casts.
Reported by 長田偉伸, and with help from Rici Lake.
See also
http://lists.gnu.org/archive/html/bug-bison/2013-02/msg00000.html
and commit 75ae829984.
* data/location.cc (position::add_): Take min as an int.
Use std::max.
While here, get rid of a couple of useless inlines.
* doc/bison.texi (Mid-Rule Actions): Restructure to insert...
(Typed Mid-Rule Actions): this new section.
Move the manual translation of mid-rule actions into regular actions
to...
(Mid-Rule Action Translation): here.
Reported by Jannick.
http://lists.gnu.org/archive/html/bug-bison/2017-05/msg00001.html
"Amusingly" enough, we have the same problem with %defines when the
parser file name has backslashes or quotes: we generate #includes with
an incorrect C string.
* src/output.c (prepare_symbol_definitions): Escape properly the file
names before passing them to M4.
* data/bison.m4, data/lalr1.cc: Don't simply put the file name between
two quotes (that should have been strong enough a smell...), expect
the string to be properly quoted.
* tests/synclines.at: New tests to check this.
Suggested by Paul Eggert.
* src/reader.c (find_start_symbol): Don't check 'res', we know it is
not null. That suffices to avoid the GCC warnings.
* bootstrap.conf: We don't need 'assume', which doesn't exist anyway.
In 0931d14728 I removed too many
initializations from some ctors: some were not about base ctors, but
about member variables. In fact, more of them were missing to please
GCC 8.
While at it, generate more natural code for C++ without variant:
instead of
template <typename Base>
parser::basic_symbol<Base>::basic_symbol (const basic_symbol& other)
: Base (other)
, value ()
{
value = other.value
}
generate
template <typename Base>
parser::basic_symbol<Base>::basic_symbol (const basic_symbol& other)
: Base (other)
, value (other.value)
{}
* data/c++.m4 (basic_symbol::basic_symbol): Always initialize 'value',
it might be a POD without a ctor.
* data/lalr1.cc (stack_symbol_type::stack_symbol_type): Likewise.
* data/variant.hh (variant::variant): Default initialize the buffer too.
GCC 8 issues warnings whose root cause was a bit hard to find.
calc.cc: In member function 'virtual int yy::parser::parse()':
calc.cc:810:18: warning: '*((void*)&<anonymous> +8)' may be used uninitialized in this function [-Wmaybe-uninitialized]
, location (l)
^
calc.cc: In member function 'void yy::parser::yypush_(const char*, yy::parser::stack_symbol_type&)':
calc.cc:810:18: warning: '*((void*)&<anonymous> +8)' may be used uninitialized in this function [-Wmaybe-uninitialized]
, location (l)
^
calc.cc: In member function 'void yy::parser::yypush_(const char*, yy::parser::state_type, yy::parser::symbol_type&)':
calc.cc:810:18: warning: '*((void*)&<anonymous> +8)' may be used uninitialized in this function [-Wmaybe-uninitialized]
, location (l)
^
The problem is with locations that don't have a constructor, such as
Span (in calc.cc) which is POD. It is POD on purpose: so that we can
use that structure to test glr.cc which cannot use non POD in its
(C) stacks.
* data/c++.m4 (basic_symbol): Also ensure that 'location' is
initialized.
With GCC 7.3.0 and Flex 2.6.4, we get warnings on all the generated
scanners:
examples/calc++/calc++-scanner.cc: In function 'void yyrestart(FILE*)':
examples/calc++/calc++-scanner.cc:1611:20: error: potential null pointer dereference [-Werror=null-dereference]
/* %endif */
~~~~~~~~~~~ ^
examples/calc++/calc++-scanner.cc:1607:19: error: potential null pointer dereference [-Werror=null-dereference]
/* %if-c-only */
~~~~~~~~~~~~~~~ ^
examples/calc++/calc++-scanner.cc:1611:20: error: potential null pointer dereference [-Werror=null-dereference]
/* %endif */
~~~~~~~~~~~ ^
examples/calc++/calc++-scanner.cc:1607:19: error: potential null pointer dereference [-Werror=null-dereference]
/* %if-c-only */
~~~~~~~~~~~~~~~ ^
cc1plus: all warnings being treated as errors
Obviously the lines are incorrect, and the warnings are emitted twice.
Still, let's get rid of these warnings.
* doc/bison.texi, src/flex-scanner.h: Disable these warnings in code
generated by Flex.
Commit 3df32101e7 introduced invalid C
code. Caught by GCC 7.3.0.
* bootstrap.conf (gnulib_modules): We need assume.
* src/reader.c (find_start_symbol): Fix the signature (too much C++,
sorry...).
Prefer 'assume' to 'assert', so that we don't have these warnings even
when NDEBUG is defined.
This file was meant to be shown as an example. Install it.
* README, data/README: Put Emacs metadata in the final section.
* examples/README: New.
* examples/variant.yy: Use %empty.
* examples/local.mk: Install both these files.
We currently generate copy constructors such as the following
one (taken from examples/variant.yy):
parser::stack_symbol_type::stack_symbol_type (const stack_symbol_type& that)
: super_type (that.state, that.location)
{
switch (that.type_get ())
{
case 3: // TEXT
case 8: // item
value.copy< ::std::string > (that.value);
break;
case 7: // list
value.copy< ::std::vector<std::string> > (that.value);
break;
case 4: // NUMBER
value.copy< int > (that.value);
break;
default:
break;
}
}
they are actually useless: we never need it.
* data/lalr1.cc: Don't generate the stack_symbol_type copy ctor.
Fix a typo so that instead of
basic_symbol::basic_symbol (typename Base::kind_type t, const int v)
we now generate
basic_symbol::basic_symbol (typename Base::kind_type t, const int& v)
* data/variant.hh (b4_basic_symbol_constructor_declare)
(b4_basic_symbol_constructor_define): Add missing reference.
Several features were flagged 'experimental' and waiting for user
feedback to 'stabilize', but i. AFAIK, no user ever reported anything
about them, ii. they'be been here long enough to prove they don't do
harm.
* doc/bison.texi: No longer experimental: default %printer and
%destructor (typed: <*> and untyped: <>), %define api.value.type union
and variant, Java parsers, XML output, LR family (lr, ielr, lalr),
semantic predicates (%?).
* tests/actions.at: Fix some log messages.
Prefer #error to fprintf: it fixes the invalid use of yyoutput in
%destructor, and it is an even stronger check: that the code is not
even emitted. The portability of #error is not really a problem here,
since the point is anyway to have the compilation fail.
