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.
Make sure that we cannot apply a type to the (main) action of a rule.
* src/reader.c (grammar_rule_check): Issue the warning.
* tests/input.at (Cannot type action): Check the warning.
* tests/input.at (_AT_UNUSED_VALUES_DECLARATIONS): Check
typed mid-rule actions.
* tests/report.at (Reports): Check that types of typed mid-rule
actions are reported.
* tests/actions.at (Typed mid-rule actions): Check that
the values of typed mid-rule actions are correct.
Prompted on Piotr Marcińczyk's message:
http://lists.gnu.org/archive/html/bug-bison/2017-06/msg00000.html.
See also http://lists.gnu.org/archive/html/bug-bison/2018-06/msg00001.html.
Because their type is unknown to Bison, the values of midrule actions are
not treated like the others: they don't have %printer and %destructor
support. In addition, in C++, (Bison) variants cannot work properly.
Typed midrule actions address these issues. Instead of:
exp: { $<ival>$ = 1; } { $<ival>$ = 2; } { $$ = $<ival>1 + $<ival>2; }
write:
exp: <ival>{ $$ = 1; } <ival>{ $$ = 2; } { $$ = $1 + $2; }
* src/scan-code.h, src/scan-code.l (code_props): Add a `type` field to
record the declared type of an action.
(code_props_rule_action_init): Add a type argument.
* src/parse-gram.y: Accept an optional type tag for actions.
* src/reader.h, src/reader.c (grammar_current_rule_action_append): Add
a type argument.
(grammar_midrule_action): When a mid-rule is typed, pass its type to
the defined dummy non terminal symbol.
grammar_current_rule_action_append was used in two different places:
for actual action (`{...}`), and for predicates (`%?{...}`). Let's
split this in two different functions.
* src/reader.h, src/reader.c (grammar_current_rule_predicate_append): New.
Extracted from...
(grammar_current_rule_action_append): here.
Remove arguments that don't apply.
Adjust dependencies.
