Currently, occurrences of these identifiers in the user's input yield
spurious warnings.
To tell the difference between a legitimate m4_foo from the user, and
a bad m4_foo coming from a non-evaluated macro of a skeleton, escape
the user's identifiers as m4@'_foo. We already use @' as a special
sequence to be stripped from the skeleton's output.
See <https://lists.gnu.org/r/bug-bison/2021-10/msg00026.html> and
previous commit ("warnings: be less picky about occurrences of m4_/b4_
in the output").
* src/flex-scanner.h (OBSTACK_SGROW): New.
* src/output.c (output_escaped): Escape m4_ and b4_.
* src/scan-code.l: Likewise.
* src/system.h (obstack_escape): Likewise.
And rewrite as a function.
* tests/skeletons.at (Suspicious sequences): Make sure the user can
use m4_foo/b4_foo without spurious warnings.
The recent changes to comply with POSIX are breaking Automake's test
suite.
Reported by Kiyoshi Kanazawa.
<https://lists.gnu.org/r/bug-bison/2021-09/msg00005.html>
To limit the impact of POSIX changes, bind them to $POSIXLY_CORRECT.
Suggested by Karl Berry.
<https://lists.gnu.org/r/bug-bison/2021-09/msg00009.html>
The existing `maintainer-check-posix` Make target checks these
changes.
* src/getargs.h, src/getargs.c (set_yacc): New.
Use it.
* data/skeletons/bison.m4 (b4_posix_if): New.
* data/skeletons/yacc.c (b4_declare_yyerror_and_yylex): Use it.
* doc/bison.texi, tests/local.at: Adjust.
Contrary to what commit d8cc6b073e "c++:
shorten the assertions that check whether tokens are correct"
believed, MS Visual C++'s preprocessor limitation is not on the input
line length, but on the size of the line holding the full C++
statement.
Reported by Vince Huffaker <vince@vincejulie.com>
<https://lists.gnu.org/r/help-bison/2021-08/msg00003.html>
* data/skeletons/variant.hh (_b4_symbol_constructor_define): Hide the
assertion from Visual C++.
In POSIX Yacc mode, declare yyerror and yylex unless already #defined,
or if YYERROR_IS_DECLARED/YYLEX_IS_DECLARED are defined (for
consistency with Bison's YYSTYPE_IS_DECLARED/YYLTYPE_IS_DECLARED).
See <https://austingroupbugs.net/view.php?id=1388#c5220>.
* data/skeletons/c.m4 (b4_function_declare): Resurect.
(b4_lex_formals): Since we will possibly expose this prototype
in the header, take the prefix into account.
* data/skeletons/yacc.c (b4_declare_yyerror_and_yylex): New.
(b4_shared_declarations): Use it.
* tests/local.at (AT_YACC_IF): New.
When in Yacc mode, set the `yacc` Autotest keyword.
(AT_YYERROR_DECLARE(c)): Don't declare in Yacc mode,
to avoid clashes (since this signature is static).
(AT_YYERROR_DEFINE(c)): Don't define as static in Yacc mode.
* tests/regression.at (Early token definitions with --yacc): Specify
that we are in Yacc mode.
When a pstate is used for multiple successive parses, some state may
leak from one run into the following one. That was introduced in
330552ea49 "yacc.c: push: don't clear
the parser state when accepting/rejecting".
Reported by Ryan <dev@splintermail.com>
https://lists.gnu.org/r/bug-bison/2021-03/msg00000.html
* data/skeletons/yacc.c (yypush_parse): We reusing a pstate from a
previous run, do behave as if it were the first run.
* tests/push.at (Pstate reuse): Check this.
The right-shift added in c22902e360
("tables: fix handling for useless tokens") is incorrect. In
particular, we need to reset the "new" bits.
Reported by Balázs Scheidler.
https://github.com/akimd/bison/issues/74
* src/tables.c (pos_set_set): Fix the right-shift.
That change was started in Bison 3.4. The announcement for 3.7 stated
that in Bison 3.8 we would use *.gv by default.
* src/files.c (compute_output_file_names): spec_graph_file defaults
too *.gv.
* doc/bison.texi, examples/c++/calc++/local.mk, tests/output.at:
Adjust.
Its removal was annonced several times in NEWS (for Bison 3.5, 3.6, 3.7).
* data/skeletons/c.m4, data/skeletons/yacc.c: Remove support for YYPRINT.
* NEWS: Fix the mess introduced by the merge.
Document the removal of YYPRINT.
* doc/bison.texi (The YYPRINT Macro): Remove.
We have been accepting this for years, but it is deprecated: people
are expecting to define api.value.type instead.
* doc/bison.texi: Make it clear that YYSTYPE and YYLTYPE are for C
only.
Three new commits:
commit 8358090292
Author: Paul Eggert <eggert@cs.ucla.edu>
Date: Wed Jan 20 18:30:16 2021 -0800
c: port to HP-UX 11.23
commit 2c294c1325
Author: Vincent Imbimbo <vmi6@cornell.edu>
Date: Sat Jan 23 13:25:18 2021 -0500
cex: fix state-item pruning
commit c22902e360
Author: Akim Demaille <akim.demaille@gmail.com>
Date: Sat Jan 23 18:40:15 2021 +0100
tables: fix handling for useless tokens
In some rare conditions, the generated parser can be wrong when there
are useless tokens.
Reported by Balázs Scheidler.
https://github.com/akimd/bison/issues/72
Balázs managed to prove that the bug was introduced in
commit af1c6f973a
Author: Theophile Ranquet <ranquet@lrde.epita.fr>
Date: Tue Nov 13 10:38:49 2012 +0000
tables: use bitsets for a performance boost
Suggested by Yuri at
<http://lists.gnu.org/archive/html/bison-patches/2012-01/msg00000.html>.
The improvement is marginal for most grammars, but notable for large
grammars (e.g., PosgreSQL's postgre.y), and very large for the
sample.y grammar submitted by Yuri in
http://lists.gnu.org/archive/html/bison-patches/2012-01/msg00012.html.
Measured with --trace=time -fsyntax-only.
parser action tables postgre.y sample.y
Before 0,129 (44%) 37,095 (99%)
After 0,117 (42%) 5,046 (93%)
* src/tables.c (pos): Replace this set of integer coded as an unsorted
array of integers with...
(pos_set): this bitset.
which was implemented long ago, but that I installed only recently
(March 2019), first published in v3.3.90.
That patch introduces a bitset to represent a set of integers. It
managed negative integers by using a (fixed) base (the smallest
integer to represent). It avoided negative accesses into the bitset
by ignoring integers smaller than the base, under the asumption that
these cases correspond to useless tokens that are ignored anyway.
While it turns out to be true for all the test cases in the test suite
(!), Balázs' use case demonstrates that it is not always the case.
So we need to be able to accept negative integers that are smaller
than the current base.
"Amusingly" enough, the aforementioned patch was visibly unsure about
itself:
/* Store PLACE into POS_SET. PLACE might not belong to the set
of possible values for instance with useless tokens. It
would be more satisfying to eliminate the need for this
'if'. */
This commit needs several improvements in the future:
- support from bitset for bit assignment and shifts
- amortized resizing of pos_set
- test cases
* src/tables.c (pos_set_base, pos_set_dump, pos_set_set, pos_set_test):
New.
Use them instead of using bitset_set and bitset_test directly.
There were several bugs in pruning that would leave the state-item
graph in an inconsistent state which could cause crashes later on:
- Pruning now happens in one pass instead of two.
- Disabled state-items no longer prune the state-items they transition
to if that state-item has other states that transition to it.
- State-items that transition to disabled state-items are always
pruned even if they have productions.
Reported by Michal Bartkowiak <michal.bartkowiak@nokia.com>
https://lists.gnu.org/r/bug-bison/2021-01/msg00000.html
and Zartaj Majeed
https://github.com/akimd/bison/issues/71
* src/state-item.c (prune_forward, prune_backward): Fuse into...
(prune_state_item): this.
Adjust callers.
Suggested by Joe Nelson <joe@begriffs.com>.
https://lists.gnu.org/r/help-bison/2020-12/msg00020.html
* data/skeletons/glr.c, data/skeletons/yacc.c (YYNOMEM): New.
Use it.
(yyexhaustedlab): Rename as...
(yynomemlab): this.
* tests/calc.at: Check it.
* doc/bison.texi: Document it.
Fix incorrect statements about non-existing constants for YYERROR etc.
Currently deferred reductions are not "verbose" at all: only immediate
reductions are displayed in the YYDEBUG traces. I don't understand
why. Besides it seems actually simpler the install the reduction
traces right around the user action inside yyuserAction rather that
around calls to yyuserAction.
This only trouble is that yyuserAction does not know the stack number
it works on, so we have to pass it. And pass -1 when we are actually
running on a temporary stack.
The glr example, on "T(x) + y;" as input, adds these logs, which
allow to see when the `<cast>` is built:
Stack 0 Entering state 26
Reduced stack 0 by rule 7 (line 108); action deferred. Now in state 7.
Stack 0 Entering state 7
Reading a token
Next token is token '+' (1.6: )
Stack 1 Entering state 27
Reduced stack 1 by rule 13 (line 123); action deferred. Now in state 12.
Stack 1 Entering state 12
Next token is token '+' (1.6: )
Stack 1 dies.
Removing dead stacks.
On stack 0, shifting token '+' (1.6: )
Stack 0 now in state #14
+Reducing stack -1 by rule 6 (line 107):
+ $1 = token identifier (1.3: x)
+-> $$ = nterm expr (1.3: x)
+Reducing stack -1 by rule 7 (line 108):
+ $1 = token typename (1.0: T)
+ $2 = token '(' (1.2: )
+ $3 = nterm expr (1.3: x)
+ $4 = token ')' (1.4: )
+-> $$ = nterm expr (1.0-3: <cast>(x,T))
Returning to deterministic operation.
* data/skeletons/glr.c (yyuserAction): Take yyk as a new argument.
Rename argument yyn as yyrule for clarity.
Log before and after the user action.
Adjust callers to not call YY_REDUCE_PRINT and YY_SYMBOL_PRINT.
We always refer to the triplet "kind, value, location". All of them
are nouns, and we support api.value.type and api.location.type. On
this regard, "semantic_type" was a poor choice. Make it "value_type".
The test suite was not updated to use value_type, on purpose, to
enforce backward compatibility.
* data/skeletons/c++.m4, data/skeletons/glr.cc, data/skeletons/glr2.cc,
* data/skeletons/variant.hh, doc/bison.texi: Define value_type rather
than semantic_type.
Add a backward compatibility typedef.
* examples/c++/glr/c++-types.yy: Migrate.
* maint:
c++: shorten the assertions that check whether tokens are correct
c++: don't glue functions together
lalr1.cc: YY_ASSERT should use api.prefix
c++: don't use YY_ASSERT at all if parse.assert is disabled
c++: style: follow the Bison m4 quoting pattern
yacc.c: provide the Bison version as an integral macro
regen
style: make conversion of version string to int public
%require: accept version numbers with three parts ("3.7.4")
yacc.c: fix #definition of YYEMPTY
gnulib: update
doc: fix incorrect section title
doc: minor grammar fixes in counterexamples section
Before:
YY_ASSERT (tok == token::YYEOF || tok == token::YYerror || tok == token::YYUNDEF || tok == 120 || tok == 49 || tok == 50 || tok == 51 || tok == 52 || tok == 53 || tok == 54 || tok == 55 || tok == 56 || tok == 57 || tok == 97 || tok == 98);
After:
YY_ASSERT (tok == token::YYEOF
|| (token::YYerror <= tok && tok <= token::YYUNDEF)
|| tok == 120
|| (49 <= tok && tok <= 57)
|| (97 <= tok && tok <= 98));
Clauses are now also wrapped on several lines. This is nicer to read
and diff, but also avoids pushing Visual C++ to its arbitrary
limits (640K and lines of 16380 bytes ought to be enough for anybody,
otherwise make an C2026 error).
The useless parens are there for the dummy warnings about
precedence (in the future, will we also have to put parens in
`1+2*3`?).
* data/skeletons/variant.hh (_b4_filter_tokens, b4_tok_in, b4_tok_in):
New.
(_b4_token_constructor_define): Use them.
Working on the previous commit I realized that YY_ASSERT was used in
the generated headers, so must follow api.prefix to avoid clashes when
multiple C++ parser with variants are used.
Actually many more macros should obey api.prefix (YY_CPLUSPLUS,
YY_COPY, etc.). There was no complaint so far, so it's not urgent
enough for 3.7.4, but it should be addressed in 3.8.
* data/skeletons/variant.hh (b4_assert): New.
Use it.
* tests/local.at (AT_YYLEX_RETURN): Fix.
* tests/headers.at: Make sure variant-based C++ parsers are checked
too.
This test did find that YY_ASSERT escaped renaming (before the fix in
this commit).
In some extreme situations (about 800 tokens), we generate a
single-line assertion long enough for Visual C++ to discard the end of
the line, thus falling into parse ends for the missing `);`. On a
shorter example:
YY_ASSERT (tok == token::TOK_YYEOF || tok == token::TOK_YYerror || tok == token::TOK_YYUNDEF || tok == token::TOK_ASSIGN || tok == token::TOK_MINUS || tok == token::TOK_PLUS || tok == token::TOK_STAR || tok == token::TOK_SLASH || tok == token::TOK_LPAREN || tok == token::TOK_RPAREN);
Whether NDEBUG is used or not is irrelevant, the parser dies anyway.
Reported by Jot Dot <jotdot@shaw.ca>.
https://lists.gnu.org/r/bug-bison/2020-11/msg00002.html
We should avoid emitting lines so long.
We probably should also use a range-based assertion (with extraneous
parens to pacify fascist compilers):
YY_ASSERT ((token::TOK_YYEOF <= tok && tok <= token::TOK_YYUNDEF)
|| (token::TOK_ASSIGN <= tok && ...)
But anyway, we should simply not emit this assertion at all when not
asked for.
* data/skeletons/variant.hh: Do not define, nor use, YY_ASSERT when it
is not enabled.
