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headers: move CPP guards into YY_*_INCLUDED to avoid collisions

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See <http://lists.gnu.org/archive/html/bug-bison/2012-09/msg00016.html>.

* data/c.m4 (b4_cpp_guard): Prepend YY_ and append _INCLUDED.
* tests/headers.at: Adjust.
* NEWS, doc/bison.texi: Document.
This commit is contained in:
Akim Demaille
2012-09-27 09:43:49 +02:00
parent 5a05f42ecf
commit c9d5bcc938
4 changed files with 33 additions and 4 deletions
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11
NEWS
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@@ -26,6 +26,17 @@ GNU Bison NEWS
foo.y:5.10-25: result type clash on merge function 'merge': <t3> != <t2> foo.y:5.10-25: result type clash on merge function 'merge': <t3> != <t2>
foo.y:4.13-27: previous declaration foo.y:4.13-27: previous declaration
** Header guards (yacc.c, glr.c, glr.cc)
In order to avoid collisions, the header guards are now
YY_<PREFIX>_<FILE>_INCLUDED, instead of merely <PREFIX>_<FILE>.
For instance the header generated from
%define api.prefix "calc"
%defines "lib/parse.h"
will use YY_CALC_LIB_PARSE_H_INCLUDED as guard.
* Noteworthy changes in release 2.6.2 (2012-08-03) [stable] * Noteworthy changes in release 2.6.2 (2012-08-03) [stable]
** Bug fixes ** Bug fixes

2
data/c.m4
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@@ -30,7 +30,7 @@ m4_define([b4_tocpp],
# ------------------ # ------------------
# A valid C macro name to use as a CPP header guard for FILE. # A valid C macro name to use as a CPP header guard for FILE.
m4_define([b4_cpp_guard], m4_define([b4_cpp_guard],
[b4_tocpp(m4_defn([b4_prefix])/[$1])]) [[YY_]b4_tocpp(m4_defn([b4_prefix])/[$1])[_INCLUDED]])
# b4_cpp_guard_open(FILE) # b4_cpp_guard_open(FILE)

17
doc/bison.texi
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@@ -5124,6 +5124,23 @@ Values, ,Semantic Values of Tokens}.
If you have declared @code{%code requires} or @code{%code provides}, the output If you have declared @code{%code requires} or @code{%code provides}, the output
header also contains their code. header also contains their code.
@xref{%code Summary}. @xref{%code Summary}.
@cindex Header guard
The generated header is protected against multiple inclusions with a C
preprocessor guard: @samp{YY_@var{PREFIX}_@var{FILE}_INCLUDED}, where
@var{PREFIX} and @var{FILE} are the prefix (@pxref{Multiple Parsers,
,Multiple Parsers in the Same Program}) and generated file name turned
uppercase, with each series of non alphanumerical characters converted to a
single underscore.
For instance with @samp{%define api.prefix "calc"} and @samp{%defines
"lib/parse.h"}, the header will be guarded as follows.
@example
#ifndef YY_CALC_LIB_PARSE_H_INCLUDED
# define YY_CALC_LIB_PARSE_H_INCLUDED
...
#endif /* ! YY_CALC_LIB_PARSE_H_INCLUDED */
@end example
@end deffn @end deffn
@deffn {Directive} %defines @var{defines-file} @deffn {Directive} %defines @var{defines-file}

7
tests/headers.at
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@@ -167,13 +167,14 @@ AT_BISON_CHECK([-d -o AT_SKEL_CC_IF([$1.cc $1.yy], [$1.c $1.y])])
AT_SKEL_CC_IF([], AT_SKEL_CC_IF([],
[AT_CHECK([$EGREP yy $1.h], [1])]) [AT_CHECK([$EGREP yy $1.h], [1])])
# Ignore comments. Ignore YYPARSE_PARAM (obsolete) and # Check there is not 'YY' left.
# YYPUSH_MORE(_DEFINED)? (whose definition is constant). # Ignore comments, YYPARSE_PARAM (obsolete), YYPUSH_MORE(_DEFINED)?
# (constant definition), YY_\w+_INCLUDED (header guards).
# #
# YYDEBUG (not renamed) can be read, but not changed. # YYDEBUG (not renamed) can be read, but not changed.
AT_CHECK([[sed -ne 's,/\*[^*]*\*/,,g;s,//.*,,' \ AT_CHECK([[sed -ne 's,/\*[^*]*\*/,,g;s,//.*,,' \
-e '/YY/p' ]$1.AT_SKEL_CC_IF([hh], [h])[ | -e '/YY/p' ]$1.AT_SKEL_CC_IF([hh], [h])[ |
$EGREP -wv 'YY(PARSE_PARAM|PUSH_MORE(_DEFINED)?)|(defined|if) YYDEBUG']], $EGREP -wv 'YY(PARSE_PARAM|PUSH_MORE(_DEFINED)?|_[0-9A-Z_]+_INCLUDED)|(defined|if) YYDEBUG']],
[1]) [1])
AT_LANG_COMPILE([$1.o]) AT_LANG_COMPILE([$1.o])