diff options
| author | Akim Demaille <akim.demaille@gmail.com> | 2021-01-31 16:05:13 +0100 |
|---|---|---|
| committer | Akim Demaille <akim.demaille@gmail.com> | 2021-02-01 05:54:06 +0100 |
| commit | 9acc9d2aeeee21be4572a0eaac6146867f264243 (patch) | |
| tree | 833812ec39398a25a1510d902c452bfc71e15d3d /data | |
| parent | dc8fe0678a6f32a1d755bb163efcac42976220d9 (diff) | |
| download | bison-9acc9d2aeeee21be4572a0eaac6146867f264243.tar.gz | |
c++: issue a compile-time warning when #define YYSTYPE is used
Using #define YYSTYPE has always been strongly discouraged in C++.
Macros are dangerous and can result in subtle bugs.
https://lists.gnu.org/r/bug-bison/2020-12/msg00007.html
Maybe some people are currently using #define YYSTYPE. Instead of
dropping support right now, first issue a warning. Bison can "see" if
YYDEBUG is defined (it could even be on the command line), only the
compiler knows. Unfortunately `#warning` is non-portable, and
actually GCC even dies on it when `-pedantic` is enabled. So we need
to use `#pragma message`. We must make it conditional as some
compilers might not support it, but it doesn't matter if only _some_
compilers emit the warning: it should be enough to catch the attention
of the developers.
* data/skeletons/c++.m4: Issue a warning when the user defined
YYSTYPE.
* tests/actions.at: Don't #define YYSTYPE.
* tests/headers.at (Several parsers): Ignore the YYSTYPE in the
warning.
Diffstat (limited to 'data')
| -rw-r--r-- | data/skeletons/c++.m4 | 9 |
1 files changed, 6 insertions, 3 deletions
diff --git a/data/skeletons/c++.m4 b/data/skeletons/c++.m4 index 212978a2..cd6fdb03 100644 --- a/data/skeletons/c++.m4 +++ b/data/skeletons/c++.m4 @@ -227,10 +227,13 @@ m4_define([b4_value_type_declare], # Define the public types: token, semantic value, location, and so forth. # Depending on %define token_lex, may be output in the header or source file. m4_define([b4_public_types_declare], -[[#ifndef ]b4_api_PREFIX[STYPE -]b4_value_type_declare[ -#else +[[#ifdef ]b4_api_PREFIX[STYPE +# ifdef __GNUC__ +# pragma GCC message "bison: do not #define ]b4_api_PREFIX[STYPE in C++, use %define api.value.type" +# endif typedef ]b4_api_PREFIX[STYPE value_type; +#else +]b4_value_type_declare[ #endif /// Backward compatibility (Bison 3.8). typedef value_type semantic_type;]b4_locations_if([ |