* data/README: Convert to Markdown.
Start documenting some of the macros used in all our skeletons.
Simplify and fix the documentation of the macros in the skeletons.
Currently it is the front end that passes the symbol types to the
backend. For instance:
%token <ival> NUM
%type <ival> exp1 exp2
exp1: NUM { $$ = $1; }
exp2: NUM { $<ival>$ = $<ival>1; }
In both cases, $$ and $1 are passed to the backend as having type
'ival' resulting in code like `val.ival`. This is troublesome in the
case of api.value.type=union, since in that the case the code this:
%define api.value.type union
%token <int> NUM
%type <int> exp1 exp2
exp1: NUM { $$ = $1; }
exp2: NUM { $<int>$ = $<int>1; }
because in this case, since the backend does not know the symbol being
processed, it is forced to generate casts in both cases: *(int*)(&val)`.
This is unfortunate in the first case (exp1) where there is no reason
at all to use a cast instead of `val.NUM` and `val.exp1`.
So instead delegate the computation of the actual value type to the
backend: pass $<ival>$ as `symbol-number, ival` and $$ as
`symbol-number, MULL`, instead of passing `ival` before.
* src/scan-code.l (handle_action_dollar): Find the symbol the action
is about, not just its tyye. Pass both symbol-number, and explicit
type tag ($<tag>n when there is one) to b4_lhs_value and b4_rhs_value.
* data/bison.m4 (b4_symbol_action): adjust to the new signature to
b4_dollar_pushdef.
* data/c-like.m4 (_b4_dollar_dollar, b4_dollar_pushdef): Accept the
symbol-number as new argument.
* data/c.m4 (b4_symbol_value): Accept the symbol-number as new
argument, and use it.
(b4_symbol_value_union): Accept the symbol-number as new
argument, and use it to prefer ready a union member rather than
casting the union.
* data/yacc.c (b4_lhs_value, b4_rhs_value): Accept the new
symbol-number argument.
Adjust uses of b4_dollar_pushdef.
* data/glr.c (b4_lhs_value, b4_rhs_value): Adjust.
* data/lalr1.cc (b4_symbol_value_template, b4_lhs_value): Adjust
to the new symbol-number argument.
* data/variant.hh (b4_symbol_value, b4_symbol_value_template): Accept
the new symbol-number argument.
* data/java.m4 (b4_symbol_value, b4_rhs_data): New.
(b4_rhs_value): Use them.
* data/lalr1.java: Adjust to b4_dollar_pushdef, and use b4_rhs_data.
* data/bison.m4, data/c++.m4, data/glr.c, data/java.m4, data/lalr1.cc,
* data/yacc.c, src/scan-code.l:
Fix comments.
Prefer POS to denote the position of a symbol in a rule, since NUM
is also used to denote symbol numbers.
Reported by Uxio Prego.
https://lists.gnu.org/archive/html/help-bison/2018-11/msg00031.html
We also need to move the unreachable 'goto' to a reachable place,
otherwise clang complains about the code being unreachable anyway.
See also https://bugs.llvm.org/show_bug.cgi?id=39736.
Interestingly, we don't have to apply that trick to
`#define YYCDEBUG if (false) std::cerr`, clang does not warn when the
code comes from macro expansion.
* configure.ac: Use -Wunreachable-code when supported.
* data/lalr1.cc, data/yacc.c: Pacify clang's warning about `if (0)`
by using a macro.
Another possibility was to move this statement to a reachable place.
* tests/actions.at, tests/c++.at: Avoid generating unreachable code.
We should probably introduce some struct and functions to deal with
stack management, rather than open coding it. yyparse would be much
nicer to read, and a better model for possible other skeletons.
* data/yacc.c (yyparse::yysetstate): Avoid generating code when
neither yyoverflow nor YYSTACK_RELOCATE is defined.
On the CI, both GCC and Clang report:
src/parse-gram.c: In function 'yy_lac':
src/parse-gram.c:1479:29: error: format '%hd' expects argument of type 'int',
but argument 3 has type 'yytype_int16 {aka long int}' [-Werror=format=]
YYDPRINTF ((stderr, " G%hd", yystate));
^
Although yytype_int16 is supposed to be a short int, not a long int.
This must be explored.
* data/yacc.c (yy_lac): Work around typing issue.
Reported by Derek Clegg.
http://lists.gnu.org/archive/html/bug-bison/2018-10/msg00018.html
Rather than adding casts, we should be more careful with types. For
instance yystate should be a yytype_int16. But currently we can't: it
is also used sometimes for storing other things that state numbers.
* data/yacc.c (yyparse): Add missing casts.
The yacc.c skeleton is old, and was using many tricks to save
registers. Today's register allocators can do this themselves. Let's
keep the code simpler to read and let compilers do their job.
* data/yacc.c: Avoid using yystate for different types of content.
An inline function would be better, but doing this portably will be
a problem.
Currently we emit useless code for places where we might issue user
content, but there is none. This commit avoids this. Besides, some
of the comments looked like implementation details ("Copy the first
part of user declarations"), rather than made for the reader of the
result ("First part of user prologue").
On Bison's parse-gram.c we get:
@@ -76,10 +76,6 @@
#define yynerrs gram_nerrs
-/* Copy the first part of user declarations. */
-
-#line 82 "src/parse-gram.c" /* yacc.c:339 */
-
* data/bison.m4 (b4_define_user_code): Accept a comment to document
the section.
Do not emit any code if the content is empty.
Adjust callers to not emit the comment.
Do not
* data/glr.c, data/glr.cc, data/lalr1.cc, data/lalr1.java, data/yacc.c:
Adjust.
We use both styles, let's stick to a single one. Autoconf uses the
prefix one, let's do the same.
* data/bison.m4, data/c++.m4, data/c-like.m4, data/lalr1.cc,
* data/variant.hh, data/yacc.c: Rename all the b4_*_ macros
as _b4_*.
At least GCC 7.3, with -O1 or -O2 (but not -O0 or -O3) generates
warnings with -Wnull-dereference when using yyformat: it fails to see
yyformat cannot be null.
Reported by Frank Heckenbach, https://savannah.gnu.org/patch/?9620.
* configure.ac: Use -Wnull-dereference if supported.
* data/glr.c, data/lalr1.cc, data/yacc.c: Define yyformat in such
a way that GCC cannot not see that yyformat is defined.
Using `default: abort();` also addresses the issue, but forces
the inclusion of `stdlib.h`, which we avoid.
Currently lalr1.cc makes an out-of-bound access when trying to read @1
in rules with an empty rhs (i.e., when there is no @1) that raises an
error (YYERROR).
glr.c already gracefully handles this by using @$ as initial location
for the errors. Let's do that in yacc.c and lalr1.cc.
* data/lalr1.cc, data/yacc.c: Use @$ to initialize the error location.
* tests/actions.at: Check that case.
Again some issues with the fact that yylval is reported by GCC as
possibly not initialized in some cases. Here, the case at hand is the
%destructor.
I am still not convinced that it is worth going all the trouble of
using pragmas to disable temporarily some warnings, instead of just
initializing the looking symbol once for all, but that's what Paul
voted for, see
<http://lists.gnu.org/archive/html/bison-patches/2012-10/msg00050.html>.
* data/c.m4 (b4_attribute_define): Define
YY_IGNORE_MAYBE_UNINITIALIZED_BEGIN, YY_IGNORE_MAYBE_UNINITIALIZED_END,
YY_INITIAL_VALUE here, as we will need them in the generation of the
destructor function, which is defined in yacc.c before yyparse, which
was in charge of defining these macros.
* data/yacc.c (b4_declare_scanner_communication_variables): Simplify:
trying to factor the definitions of the case pure and impure is
too complex.
Actually, it is not even clear that this macro should really exist,
as even the calls are complex.
Be careful not to issue a lone ";", as this is a statement, and C90
forbids declarations after statements ; so write
"YY_INITIAL_VALUE(Decl;)", not "YY_INITIAL_VALUE(Decl);".
* origin/maint:
glr.cc: fix a clang warning
maint: update copyright years
build: fix VPATH issue
build: avoid clang's colored diagnostics in the test suite
tests: please clang and use ".cc", not ".c", for C++ input
gnulib: update
skeletons: avoid empty switch constructs
lalr1.cc: fix compiler warnings
yacc.c: do not use __attribute__ unprotected
tests: style changes
This is to match the names used in C and api.value.type, even if the
parser actually defines semantic_type.
* data/c++.m4 (b4_semantic_type_declare): Rename as...
(b4_value_type_declare): this.
* data/variant.hh: Likewise.
Recent changes (in 2.7) introduced a dependency on both FILE and
fprintf, which are "available" only in %debug mode. This was to
define yy_location_print_, which is used only in %debug mode by the
parser, but massively used by the test suite to output the locations
in yyerror.
Break this dependency: the test suite should define its own routines
to display the locations. Eventually Bison will provide the user with
a means to display locations, but not yet.
* data/c.m4 (b4_yy_location_print_define): Use YYFPRINTF instead of
fprintf directly.
* data/yacc.c (b4_yy_location_print_define): Invoke it only in %debug
mode, so that stdio.h is included (needed for FILE*), and YYFPRINTF
is defined.
* tests/local.at (AT_YYERROR_DECLARE, AT_YYERROR_DEFINE): Declare
and define location_print and LOCATION_PRINT.
* tests/actions.at, tests/existing.at, tests/glr-regression.at,
* tests/input.at, tests/named-refs.at, tests/regression.at: Adjust
to use them.
Fix the expected line numbers (as the prologue's length has changed).
The commit 38de4e570f underquoted the
content of the comments, which resulted in losing square brackets in
the comments. Besides, some other invocations were underquoting the
effective arguments.
* data/c.m4 (b4_comment_): Properly quote the comment.
(b4_comment_, b4_comment): Move to...
* data/c-like.m4: here, so that...
* data/java.m4: can use it instead of its own copy.
* data/bison.m4 (b4_integral_parser_tables_map): Fix some comments.
* data/lalr1.cc, data/lalr1.java, data/yacc.c: Comment fixes.
* data/lalr1.cc: Reorder a bit to factor some CPP directives.
The YYLEX existed only to support YYLEX_PARAM, which is now removed.
This macro was a nuisance, since incorrect yylex calls where pointed
the macro _use_, instead of its definition.
* data/c.m4 (b4_lex_formals, b4_lex): New.
* data/glr.c, data/yacc.c: Use it.
* data/lalr1.cc (b4_lex): New.
Use it.
squash! skeletons: no longer call yylex via a CPP macro
* origin/maint:
parser: accept #line NUM
m4: use a safer pattern to enable/disable output
tests: beware of gnulib's need for config.h
gnulib: update
yacc.c, glr.c: check and fix the display of locations
formatting changes
glr.c: remove stray macro
Conflicts:
data/c.m4
data/glr.cc
data/lalr1.cc
data/lalr1.java
data/location.cc
data/stack.hh
data/yacc.c
src/scan-gram.l
Work on some other areas of Bison revealed that some macros expanded
to be expanded only once were actually expanded several times. This
was due to the fact that changecom was not properly restored each
time, and macro names appearing in comments were then expanded.
Introduce begin/end macros which are easier to match that
changecom()/changecom(#).
* data/bison.m4 (b4_output_begin, b4_output_end): New.
* data/glr.c, data/glr.cc, data/lalr1.cc, data/lalr1.java,
* data/location.cc, data/stack.hh, data/yacc.c:
Use them.
This makes the interface for yyerror() pure without the need for a spurious
parse_param.
* data/yacc.c (b4_pure_if, b4_pure_flag): New definition, accept three states.
(b4_yacc_pure_if): Rename as...
(b4_yyerror_arg_loc_if): This, and use b4_pure_flag.
* tests/actions.at (%define api.pure): Modernize.
* test/calc.at (Simple LALR Calculator): Modernize.
* tests/local.at (AT_YYERROR_ARG_LOC_IF): Adjust.
* origin/maint:
yacc.c: always initialize yylloc
scanner: issue a single error for groups of invalid characters
tests: formatting changes
doc: one of the fixes for an ambiguous grammar was ambiguous too
doc: fix the dangling else with precedence directives
doc: prefer "token" to TOKEN
doc: formatting changes
scanner: use explicit "ignore" statements
Conflicts:
src/scan-gram.l
The initial location might be used if the parser starts by an empty
reduction, so really ensure proper initialization of the initial
location. The previous approach fails for PostgreSQL, which uses
Reported by Peter Eisentraut.
http://lists.gnu.org/archive/html/bug-bison/2012-11/msg00023.html
With help from Théophile Ranquet.
* data/yacc.c (b4_declare_scanner_communication_variables): Be sure
to initialize yylloc, even when its structure is unknown.
(yyparse): Simplify the call to b4_dollar_pushdef.
* tests/actions.at (Initial location): Check of similar pattern
as in the case of PostgreSQL.
