On Sat, 16 Sep 2017, Tom Tromey wrote:
> --- a/gcc/doc/cpp.texi
> +++ b/gcc/doc/cpp.texi
> @@ -1675,20 +1675,27 @@ macro. We could define @code{eprintf} like this,
> instead:
[snip]
> +This formulation looks more descriptive, but historically it was less
> +flexible: you had to supply at least one argument after the format
> +string. In standard C, you could not omit the comma separating the
> +named argument from the variable arguments. (Note that this
> +restriction has been lifted in C++20, and never existed in GNU C; see
> +below.)
Shouldn't this say 'C++2a' (more instances follow)?
> +Historically, GNU has also had another extension to handle the
'GNU CPP'?
> --- a/libcpp/init.c
> +++ b/libcpp/init.c
> @@ -91,28 +91,29 @@ struct lang_flags
> static const struct lang_flags lang_defaults[] =
> -{ /* c99 c++ xnum xid c11 std digr ulit rlit udlit bincst
> digsep trig u8chlit */
[snip]
> - /* GNUCXX17 */ { 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1,
> 0, 1 },
> - /* CXX17 */ { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
> 0, 1 },
> - /* GNUCXX2A */ { 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1,
> 0, 1 },
> - /* CXX2A */ { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
> 0, 1 },
> - /* ASM */ { 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
> 0, 0 }
> +{ /* c99 c++ xnum xid c11 std digr ulit rlit udlit bincst
> digsep trig u8chlit vaopt */
[snip]
> + /* GNUCXX1Z */ { 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1,
> 0, 1, 0 },
> + /* CXX1Z */ { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
> 0, 1, 0 },
> + /* GNUCXX2A */ { 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 1, 1,
> 0, 1, 1 },
> + /* CXX2A */ { 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1, 1,
> 0, 1, 1 },
> + /* ASM */ { 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0,
> 0, 0, 0 }
> };
This hunk reverts CXX17 back to CXX1Z.
> --- a/libcpp/lex.c
> +++ b/libcpp/lex.c
> @@ -1396,6 +1396,21 @@ lex_identifier_intern (cpp_reader *pfile, const uchar
> *base)
> " of a C99 variadic macro");
> }
>
> + /* __VA_OPT__ should only appear in the replacement list of a
> + variadic macro. */
> + if (result == pfile->spec_nodes.n__VA_OPT__
> + && !pfile->state.va_args_ok)
> + {
> + if (CPP_OPTION (pfile, cplusplus))
> + cpp_error (pfile, CPP_DL_ERROR,
> + "__VA_OPT__ can only appear in the expansion"
> + " of a C++11 variadic macro");
> + else
> + cpp_error (pfile, CPP_DL_ERROR,
> + "__VA_OPT__ can only appear in the expansion"
> + " of a C99 variadic macro");
> + }
> +
> /* For -Wc++-compat, warn about use of C++ named operators. */
> if (result->flags & NODE_WARN_OPERATOR)
> cpp_warning (pfile, CPP_W_CXX_OPERATOR_NAMES,
> @@ -1485,6 +1500,21 @@ lex_identifier (cpp_reader *pfile, const uchar *base,
> bool starts_ucn,
> " of a C99 variadic macro");
> }
>
> + /* __VA_OPT__ should only appear in the replacement list of a
> + variadic macro. */
> + if (result == pfile->spec_nodes.n__VA_OPT__
> + && !pfile->state.va_args_ok)
> + {
> + if (CPP_OPTION (pfile, cplusplus))
> + cpp_error (pfile, CPP_DL_ERROR,
> + "__VA_OPT__ can only appear in the expansion"
> + " of a C++11 variadic macro");
> + else
> + cpp_error (pfile, CPP_DL_ERROR,
> + "__VA_OPT__ can only appear in the expansion"
> + " of a C99 variadic macro");
> + }
> +
> /* For -Wc++-compat, warn about use of C++ named operators. */
> if (result->flags & NODE_WARN_OPERATOR)
> cpp_warning (pfile, CPP_W_CXX_OPERATOR_NAMES,
These two hunks add more duplication in already-duplicated 'if' statement
bodies. Is it possible to move the whole body to a separate function?
I guess the references to C++11 and C99 are duplicated from the preceding 'if',
but is that correct here? And why is it useful to distinguish between C and C++
for this error in the first place, why not simply say 'cpp_error (...,
"__VA_OPT__ can only appear in the expansion of a variadic macro");'?
> --- a/libcpp/macro.c
> +++ b/libcpp/macro.c
> @@ -1670,6 +1821,8 @@ replace_args (cpp_reader *pfile, cpp_hashnode *node,
> cpp_macro *macro,
> num_macro_tokens);
> }
> i = 0;
> + vaopt_state state_tracker (pfile, macro->variadic,
> + args[macro->paramc - 1].count > 0);
The name 'state_tracker' seems too general for what it does, I think
'vaopt_st' or such would have been a better fit (sorry for the bikeshed).
Thanks.
Alexander
