From ce53cf7b61ea6bce05570e2fd1f8c10eee308ab0 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Wed, 7 Dec 2022 19:18:06 +0000 Subject: [PATCH] preprocessor: Enable __VA_OPT__ for C2x C2x supports __VA_OPT__, so adjust libcpp not to pedwarn for uses of it (or of not passing any variable arguments to a variable-arguments macro) in standard C2x mode. I didn't try to duplicate existing tests for the details of the feature, just verified -pedantic-errors handling is as expected. And there's a reasonable argument (bug 98859) that __VA_OPT__ shouldn't be diagnosed in older standard modes at all (as opposed to not passing any variable arguments to a variable-arguments macro, for which older versions of the C standard require a diagnostic as a constraint violation); that argument applies to C as much as to C++, but I haven't made any changes in that regard. Bootstrapped with no regressions for x86_64-pc-linux-gnu. libcpp/ * init.cc (lang_defaults): Enable va_opt for STDC2X. * lex.cc (maybe_va_opt_error): Adjust diagnostic message for C. * macro.cc (_cpp_arguments_ok): Update comment. gcc/testsuite/ * gcc.dg/cpp/c11-vararg-1.c, gcc.dg/cpp/c2x-va-opt-1.c: New tests. --- gcc/testsuite/gcc.dg/cpp/c11-vararg-1.c | 9 +++++++++ gcc/testsuite/gcc.dg/cpp/c2x-va-opt-1.c | 11 +++++++++++ libcpp/init.cc | 2 +- libcpp/lex.cc | 10 ++++++++-- libcpp/macro.cc | 2 +- 5 files changed, 30 insertions(+), 4 deletions(-) create mode 100644 gcc/testsuite/gcc.dg/cpp/c11-vararg-1.c create mode 100644 gcc/testsuite/gcc.dg/cpp/c2x-va-opt-1.c diff --git a/gcc/testsuite/gcc.dg/cpp/c11-vararg-1.c b/gcc/testsuite/gcc.dg/cpp/c11-vararg-1.c new file mode 100644 index 00000000000..6b1bc38bb2c --- /dev/null +++ b/gcc/testsuite/gcc.dg/cpp/c11-vararg-1.c @@ -0,0 +1,9 @@ +/* Test error in C11 for no arguments passed for variable arguments to a + macro. */ +/* { dg-do preprocess } */ +/* { dg-options "-std=c11 -pedantic-errors" } */ + +#define M(X, ...) X + +M (x); /* { dg-error "requires at least one argument" } */ +M (x, y); diff --git a/gcc/testsuite/gcc.dg/cpp/c2x-va-opt-1.c b/gcc/testsuite/gcc.dg/cpp/c2x-va-opt-1.c new file mode 100644 index 00000000000..bd438f74571 --- /dev/null +++ b/gcc/testsuite/gcc.dg/cpp/c2x-va-opt-1.c @@ -0,0 +1,11 @@ +/* Test __VA_OPT__ and no "..." arguments in a call to a variable-arguments + macro accepted for C2X. */ +/* { dg-do preprocess } */ +/* { dg-options "-std=c2x -pedantic-errors" } */ + +#define CALL(F, ...) F (7 __VA_OPT__(,) __VA_ARGS__) +#define M(X, ...) X + +CALL (a); +CALL (b, 1); +M (x); diff --git a/libcpp/init.cc b/libcpp/init.cc index 5f34e3515d2..ea683f0cfaf 100644 --- a/libcpp/init.cc +++ b/libcpp/init.cc @@ -114,7 +114,7 @@ static const struct lang_flags lang_defaults[] = /* STDC99 */ { 1, 0, 1, 1, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, /* STDC11 */ { 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, /* STDC17 */ { 1, 0, 1, 1, 1, 0, 1, 1, 1, 0, 0, 0, 0, 1, 0, 0, 0, 0, 0, 0, 0, 0, 0 }, - /* STDC2X */ { 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 0, 1, 1, 0, 1, 1, 0, 1 }, + /* STDC2X */ { 1, 0, 1, 1, 1, 1, 1, 1, 1, 0, 0, 1, 1, 0, 1, 1, 1, 1, 0, 1, 1, 0, 1 }, /* GNUCXX */ { 0, 1, 1, 1, 0, 1, 0, 1, 0, 0, 0, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1 }, /* CXX98 */ { 0, 1, 0, 1, 0, 1, 1, 1, 0, 0, 0, 0, 0, 1, 0, 0, 1, 0, 0, 0, 0, 0, 1 }, /* GNUCXX11 */ { 1, 1, 1, 1, 1, 1, 0, 1, 1, 1, 1, 0, 0, 0, 0, 1, 1, 0, 0, 0, 0, 0, 1 }, diff --git a/libcpp/lex.cc b/libcpp/lex.cc index b1107920c94..9a21a3e9ecc 100644 --- a/libcpp/lex.cc +++ b/libcpp/lex.cc @@ -2135,8 +2135,14 @@ maybe_va_opt_error (cpp_reader *pfile) /* __VA_OPT__ should not be accepted at all, but allow it in system headers. */ if (!_cpp_in_system_header (pfile)) - cpp_error (pfile, CPP_DL_PEDWARN, - "__VA_OPT__ is not available until C++20"); + { + if (CPP_OPTION (pfile, cplusplus)) + cpp_error (pfile, CPP_DL_PEDWARN, + "__VA_OPT__ is not available until C++20"); + else + cpp_error (pfile, CPP_DL_PEDWARN, + "__VA_OPT__ is not available until C2X"); + } } else if (!pfile->state.va_args_ok) { diff --git a/libcpp/macro.cc b/libcpp/macro.cc index 7d5a0d0fd2e..452e14a1e66 100644 --- a/libcpp/macro.cc +++ b/libcpp/macro.cc @@ -1093,7 +1093,7 @@ _cpp_arguments_ok (cpp_reader *pfile, cpp_macro *macro, const cpp_hashnode *node if (argc < macro->paramc) { - /* In C++20 (here the va_opt flag is used), and also as a GNU + /* In C++20 and C2X (here the va_opt flag is used), and also as a GNU extension, variadic arguments are allowed to not appear in the invocation at all. e.g. #define debug(format, args...) something