Currently on the following grammar:
%type <foo> foo
%%
start: foo | bar | "baz"
foo: foo
bar: bar
bison reports:
warning: 2 nonterminals useless in grammar [-Wother]
warning: 4 rules useless in grammar [-Wother]
1.13-15: warning: nonterminal useless in grammar: foo [-Wother]
%type <foo> foo
^^^
3.14-16: warning: nonterminal useless in grammar: bar [-Wother]
start: foo | bar | "baz"
^^^
[...]
i.e., the location of the first occurrence of a symbol is taken as its
definition point. In the case of nonterminals, the first occurrence
as a left-hand side of a rule makes more sense:
warning: 2 nonterminals useless in grammar [-Wother]
warning: 4 rules useless in grammar [-Wother]
4.1-3: warning: nonterminal useless in grammar: foo [-Wother]
foo: foo
^^^
5.1-3: warning: nonterminal useless in grammar: bar [-Wother]
bar: bar
^^^
[...]
* src/symtab.h, src/symtab.c (symbol::location_of_lhs): New.
(symbol_location_as_lhs_set): New.
* src/parse-gram.y (current_lhs): Use it.
* tests/reduce.at: Update locations.
In the following grammar, the 'exp' nonterminal is trivially useless.
So, of course, its rules are useless too.
%%
input: '0' | exp
exp: exp '+' exp | exp '-' exp | '(' exp ')'
Previously all the useless rules were reported, including those whose
left-hand side is the 'exp' nonterminal:
warning: 1 nonterminal useless in grammar [-Wother]
warning: 4 rules useless in grammar [-Wother]
2.14-16: warning: nonterminal useless in grammar: exp [-Wother]
input: '0' | exp
^^^
2.14-16: warning: rule useless in grammar [-Wother]
input: '0' | exp
^^^
! 3.6-16: warning: rule useless in grammar [-Wother]
! exp: exp '+' exp | exp '-' exp | '(' exp ')'
! ^^^^^^^^^^^
! 3.20-30: warning: rule useless in grammar [-Wother]
! exp: exp '+' exp | exp '-' exp | '(' exp ')'
! ^^^^^^^^^^^
! 3.34-44: warning: rule useless in grammar [-Wother]
! exp: exp '+' exp | exp '-' exp | '(' exp ')'
! ^^^^^^^^^^^
The interest of being so verbose is dubious. I suspect most of the
time nonterminals are not expected to be useless, so the user wants to
fix the nonterminal, not remove its rules. And even if the user
wanted to get rid of its rules, the position of these rules probably
does not help more that just having the name of the nonterminal.
This commit discard these messages, marked with '!', and keep the
others. In particular, we still report:
2.14-16: warning: rule useless in grammar [-Wother]
input: '0' | exp
^^^
All the useless rules (including the '!' ones) are still reported in
the reports (xml, text, etc.); only the diagnostics on stderr change.
* src/gram.c (grammar_rules_useless_report): Don't complain about
useless rules whose lhs is useless.
* src/reduce.h, src/reduce.c (reduce_nonterminal_useless_in_grammar):
Take a sym_content as argument.
Adjust callers.
* tests/reduce.at (Useless Rules, Underivable Rules, Reduced Automaton):
Adjust.
* tests/conflicts.at (AT_CONSISTENT_ERRORS_CHECK): Move AT_SETUP/AT_CLEANUP
into it, so that we don't skip non Java tests following a test case in Java.
When using variants, destructors generate invalid code.
<http://lists.gnu.org/archive/html/bug-bison/2014-09/msg00005.html>
Reported by Michael Catanzaro.
* data/c++.m4 (~basic_symbol): b4_symbol_foreach works on yysym:
define it.
* tests/c++.at (Variants): Check it.
During error recovery, when discarding the lookeahead, we don't
destroy it, which is caught by parse.assert assertions.
Reported by Antonio Silva Correia.
With an analysis and suggested patch from Michel d'Hooge.
<http://savannah.gnu.org/support/?108481>
* tests/c++.at (Variants): Strengthen the test to try syntax errors
with discarded lookahead.
There are no support for += between locations, and some comments are wrong.
Reported by Alexandre Duret-Lutz.
* data/location.cc: Fix.
* doc/bison.texi: Document.
* tests/c++.at: Check.
Bison supports a union tag, for obscure reasons. But it does a poor
job at it, especially since Bison 3.0.
Reported by Stephen Cameron and Tobias Frost.
It did not ensure that the name was not given several times. An easy
way to do this is to make the %union tag be handled as a %define
variable, as they cannot be defined several times.
Since Bison 3.0, the synclines were wrongly placed, resulting in
invalid code. Addressing this issue, because of the way the union tag
was stored (as a code muscle), would have been tedious. Unless we
rather define the %union tag as a %percent variable, whose synclines
are easier to manipulate.
So replace the b4_union_name muscle by the api.value.union.name
%define variable, document, and check.
* data/bison.m4: Make sure that api.value.union.name has a keyword value.
* data/c++.m4: Make sure that api.value.union.name is not defined.
* data/c.m4 (b4_union_name): No longer use it, use api.value.union.name.
* doc/bison.texi (%define Summary): Document it.
* src/parse-gram.y (union_name): No longer define b4_uion_name, but
api.value.union.name.
* tests/input.at (Redefined %union name): New.
* tests/synclines.at (%union name syncline): New.
* tests/types.at: Check named %unions.
Reported by Rich Wilson.
* data/c.m4 (b4_symbol_type_register): Append to b4_union_members,
not b4_user_union_members.
The latter invokes the former, but it is the former which is reinitialized
to empty by b4_value_type_setup_union.
* tests/types.at: Check it.
This reveals another bug, this time in the case of glr.c parsers.
* data/glr.c: Generate the header file before the implementation file,
to be sure that the setup is run before what depends on it.
Reported by Alexandre Duret-Lutz as "second problem" in:
http://lists.gnu.org/archive/html/bug-bison/2013-09/msg00015.html
* bootstrap.conf: We need the "unlink" module.
* src/files.h, src/files.c (unlink_generated_sources): New.
* src/output.c: Use it.
* tests/output.at: Check the case of late errors.
Reported by Alexandre Duret-Lutz as "second problem" in:
http://lists.gnu.org/archive/html/bug-bison/2013-09/msg00015.html
One problem is that some errors are caught early, before the
generation of output files, while others can only be detected
afterwards (since, for instance, skeletons can raise errors
themselves).
This will be addressed in two steps: early errors do not generate
source files at all, while later errors will remove the files that
have already been generated.
* src/scan-skel.l (yyout): Open to /dev/null when there are errors.
* tests/output.at (AT_CHECK_FILES): Factored out of...
(AT_CHECK_OUTPUT): this.
Fuse the "SHELLIO" argument in the "FLAGS" one.
Use $5 to denote the expected exit status.
Add a test case for early errors.
When variant are enabled, the yylhs variable (the left-hand side of
the rule being reduced, i.e. $$ and @$) is explicitly destroyed when
YYERROR is called. This is because before running the user code, $$
is initialized, so that the user can properly use it.
However, when quitting yyparse, yylhs is also reclaimed by the C++
compiler: the variable goes out of scope.
Instead of trying to be too smart, let the compiler do its job: reduce
the scope of yylhs to exactly the reduction. This way, whatever the
type of scope exit (regular, exception, return, goto...) this variable
will be properly reclaimed.
Reported by Paolo Simone Gasparello.
<http://lists.gnu.org/archive/html/bug-bison/2013-10/msg00003.html>
* data/lalr1.cc (yyparse): Reduce the scope of yylhs.
* tests/c++.at: We now pass this test.
When variant are enabled, the yylhs variable (the left-hand side of
the rule being reduced, i.e. $$ and @$) is explicitly destroyed when
YYERROR is called. This is because before running the user code, $$
is initialized, so that the user can properly use it.
However, when quitting yyparse, yylhs is also reclaimed by the C++
compiler: the variable goes out of scope.
This was not detected by the test suite because (i) the Object tracker
was too weak, and (ii) the problem does not show when there is error
recovery.
Reported by Paolo Simone Gasparello.
<http://lists.gnu.org/archive/html/bug-bison/2013-10/msg00003.html>
* tests/c++.at (Exception safety): Improve the objects logger to make
sure that we never destroy twice an object.
Also track copy-constructors.
Use a set instead of a list.
Display the logs before running the function body, this is more
useful in case of failure.
Generalize to track with and without error recovery.
Building C++ parsers with -Wsuggest-attribute=const and
-Wsuggest-attribute=noreturn triggers warning in generated code.
* data/lalr1.cc: Call b4_attribute_define.
(debug_stream, debug_level): Flag as pure.
* tests/headers.at (Several parsers): There are now more YY macros
that "leak".
Some tests now fail when compiled with G++ 4.3 or 4.4 on MacPorts.
* tests/local.at (AT_SKIP_IF_EXCEPTION_SUPPORT_IS_POOR): New.
* tests/c++.at (Exception safety): Use it.
Currently "-Werror -Wno-error=foo" still turns "foo" warnings into errors.
Reported by Alexandre Duret-Lutz.
See http://lists.gnu.org/archive/html/bug-bison/2013-09/msg00015.html.
* src/complain.c (errority, errority_flag): New.
(complain_init): Initialize the latter.
(warning_argmatch): Extract the loop iterating on the flag's bits.
Set and unset errority_flag here.
(warnings_argmatch): -Wno-error is not the same as -Wno-error=everything:
we must remember if category foo was explicitly turned in an error/warning
via -W(no-)error=foo.
(warning_severity): Use errority_flag.
* tests/input.at (Symbols): Just check --yacc, not -Wyacc, that's the
job of tests on -W.
(-Werror is not affected by -Wnone and -Wall): Rename as...
(-Werror combinations): this.
Tests more combinations of -W, -W(no-)error, and -W(no-)error=foo.
* tests/local.at (AT_BISON_CHECK_WARNINGS): Don't expect -Werror
to turn runs that issue warnings into runs with errors, as the
warnings might be enforced as warnings by -Wno-error=foo, in which
case -Werror does not change anything.
* doc/bison.texi (Bison Options): Try to be clearer about how
-W(no-)error and -W(no-)error=foo interact.
* tests/c++.at (Exception safety): In variant mode $$ is an instance
of Object. Assigning YY_NULL in C++98 is incorrect, but behaves ok,
as it assigns YY_NULL=0 using Object::operator= (char v). It is wrong
in C++11 as there is operator for "$$ = nullptr".
There are possible conflicts between gnulib replacement functions (in
<stdio.h>) and their C++ wrappers (in <stream>). Trying to address
these in configure seems too hard, and I don't know how to fix the issue
in gnulib. Cowardly avoid the problem by skipping C++ tests when this
happens.
Reported by Stefano Lattarini.
http://lists.gnu.org/archive/html/bug-bison/2013-06/msg00001.html
* tests/atlocal.in (BISON_CXX_WORKS): Also set it to "skip" if we can't
compile a simple program using <stream>.
* tests/local.at: Comment changes.
* data/lalr1.java: Capture the declarations as m4 macros to avoid
duplication. When push parsing, the declarations occur at the class
instance level rather than within the parse() function.
Change the way that the parser state is initialized. For
push-parsing, the parse state declarations are moved to
"push_parse_initialize()", which is called on the first invocation of
"push_parse()". The %initial-action code is also inserted after the
invocation of "push_parse_initialize()".
The body of the parse loop is modified to return values at appropriate
points when doing push parsing. In order to make push parsing work,
it is necessary to divide YYNEWSTATE into two states: YYNEWSTATE and
YYGETTOKEN. On the first call to push_parse(), the state is
YYNEWSTATE. On all later entries, the state is set to YYGETTOKEN. The
YYNEWSTATE switch arm falls through into YYGETTOKEN. YYGETTOKEN
indicates that a new token is potentially needed. Normally, with a
pull parser, this new token would be obtained by calling "yylex()". In
the push parser, the value YYMORE is returned to the caller. On the
next call to push_parse(), the parser will return to the YYGETTOKEN
state and continue operation.
* tests/javapush.at: New test file for java push parsing.
* tests/testsuite.at: Use it.
* tests/local.mk: Adjust.
* doc/bison.texi (Java Push Parser Interface): New.
Signed-off-by: Akim Demaille <akim@lrde.epita.fr>
Some directives cannot be used several times (e.g., a given symbol may
only have a single printer). In case of repeated definitions, an
error is issued for the second definition, yet it is not discarded,
and becomes the definition used for the rest of the file.
This is not consistent with the idea that multiple definitions are not
allowed: discard any repeated directive.
* src/symtab.c (symbol_type_set, symbol_code_props_set)
(semantic_type_code_props_set, symbol_class_set, symbol_translation):
Discard repeated directives.
* tests/input.at (Default %printer and %destructor redeclared)
(Per-type %printer and %destructor redeclared): Update expectations.
* src/symtab.c (symbol_precedence_set): Use prec_location, not
location (which is the first occurrence of the symbol, possibly just
%token).
Also, as redefinitions are not allowed, keep the first values, not
the subsequent ones.
* tests/conflicts.at, tests/existing.at, tests/regression.at: Adjust.
-Wsign-compare was disabled for bison's own code, following gnulib's
approach. However, the generated parsers should not trigger such
warnings.
Reported by Efi Fogel.
http://lists.gnu.org/archive/html/help-bison/2013-04/msg00018.html
See also http://stackoverflow.com/questions/16101062 for the weird
"-(unsigned)i" piece of code.
* configure.ac (warn_tests): Enable -Wsign-compare.
* data/location.cc (position::add_): New.
(position::lines, position::columns): Use it.
* tests/actions.at (AT_CHECK_PRINTER_AND_DESTRUCTOR): Fix signedness issues.
* src/muscle-tab.c (muscle_percent_define_get_kind)
(muscle_percent_define_check_kind): New.
(muscle_percent_define_default): Variables with a default value are
of "keyword" kind.
(muscle_percent_define_flag_if, muscle_percent_define_check_values):
Check that the variable is of keyword kind.
* data/bison.m4: Likewise, but in M4. That is to say...
(b4_percent_define_default): Define the kind when the variable is undefined.
(b4_percent_define_check_kind): Use a better error message.
(_b4_percent_define_check_values, _b4_percent_define_check_values):
Former "enum" variables should be defined using the keyword syntax.
* doc/bison.texi: Update.
A couple of fixes.
* tests/input.at (%define keyword variables): New.
* src/muscle-tab.c (muscle_percent_define_ensure): Discover the virtues
of || to factor conditionals.
* NEWS: As api.pure is no longer flagged as "used" by accident,
we now have warnings for useless definitions.
* tests/calc.at: So remove api.pure settings when running C++ tests,
since C++ skeletons use a pure interface.
* data/bison.m4 (b4_percent_define_check_kind): New.
Use it to check api.token.prefix.
* data/c++.m4: Check the kind of api.namespace.
* doc/bison.texi: Update a reference to former 'namespace' variable.
* tests/input.at ("%define" code variables): Check api.namespace.
Reported by Daniel Frużyński.
http://lists.gnu.org/archive/html/bug-bison/2013-02/msg00000.html
* data/location.cc (position::columns, position::lines): Check for
underflow.
Fix some weird function signatures.
(location): Accept signed integers as arguments where appropriate.
Add operator- and operator+=.
* doc/bison.texi (C++ position, C++ location): Various fixes
and completion.
* tests/c++.at (C++ Locations): New tests.