Hi, This patch implements clang's __has_feature and __has_extension in GCC. Currently the patch aims to implement all documented features (and some undocumented ones) following the documentation at https://clang.llvm.org/docs/LanguageExtensions.html with the following omissions: - C++ type traits. - Objective-C-specific features.
C++ type traits aren't currently implemented since, as the clang documentation notes, __has_builtin is the correct "modern" way to query for these (which GCC already implements). Of course there's an argument that we should recognize the legacy set of C++ type traits that can be queried through __has_feature for backwards compatibility with older code. I'm happy to do this if reviewers think that's a good idea. There are some comments in the patch marked with XXX, I'm looking for review comments from C/C++ maintainers on those areas in particular. Bootstrapped/regtested on aarch64-linux-gnu. Any comments? Thanks, Alex gcc/c-family/ChangeLog: PR c++/60512 * c-common.cc (struct hf_feature_info): New. (has_generic_feature_p): New. * c-common.h (c_common_has_feature): New. (has_generic_feature_p): New. (has_lang_feature_p): New. * c-lex.cc (init_c_lex): Plumb through has_feature callback. (c_common_has_builtin): Adapt into more generic helper function. Rename to ... (c_common_lex_availability_macro): ... this. (c_common_has_feature): New. * c-ppoutput.cc (init_pp_output): Plumb through has_feature callback. gcc/c/ChangeLog: PR c++/60512 * c-objc-common.cc (struct c_feature_info): New. (has_lang_feature_p): New. gcc/cp/ChangeLog: PR c++/60512 * cp-objcp-common.cc (struct cp_feature_selector): New. (cp_feature_selector::has_feature): New. (struct cp_feature_info): New. (has_lang_feature_p): New. gcc/ChangeLog: PR c++/60512 * doc/cpp.texi: Document __has_{feature,extension}. libcpp/ChangeLog: PR c++/60512 * include/cpplib.h (struct cpp_callbacks): Add has_feature callback. (enum cpp_builtin_type): Add types for __has_{feature,extension}. * init.cc (builtin_array): Add entries for __has_{feature,extension}. * macro.cc (_cpp_builtin_macro_text): Handle BT_HAS_{FEATURE,EXTENSION}. gcc/testsuite/ChangeLog: PR c++/60512 * c-c++-common/has-feature-common.c: New test. * g++.dg/ext/has-feature.C: New test. * gcc.dg/asan/has-feature-asan.c: New test. * gcc.dg/has-feature.c: New test.
diff --git a/gcc/c-family/c-common.cc b/gcc/c-family/c-common.cc index 2b4c82facf7..5b8429244b2 100644 --- a/gcc/c-family/c-common.cc +++ b/gcc/c-family/c-common.cc @@ -311,6 +311,34 @@ const struct fname_var_t fname_vars[] = {NULL, 0, 0}, }; +enum +{ + HF_FLAG_EXT = 1, /* Available only as an extension. */ + HF_FLAG_SANITIZE = 2, /* Availability depends on sanitizer flags. */ +}; + +struct hf_feature_info +{ + const char *ident; + unsigned flags; + unsigned mask; +}; + +static const hf_feature_info has_feature_table[] = +{ + { "address_sanitizer", HF_FLAG_SANITIZE, SANITIZE_ADDRESS }, + { "thread_sanitizer", HF_FLAG_SANITIZE, SANITIZE_THREAD }, + { "leak_sanitizer", HF_FLAG_SANITIZE, SANITIZE_LEAK }, + { "hwaddress_sanitizer", HF_FLAG_SANITIZE, SANITIZE_HWADDRESS }, + { "undefined_behavior_sanitizer", HF_FLAG_SANITIZE, SANITIZE_UNDEFINED }, + { "attribute_deprecated_with_message", 0, 0 }, + { "attribute_unavailable_with_message", 0, 0 }, + { "enumerator_attributes", 0, 0 }, + { "tls", 0, 0 }, + { "gnu_asm_goto_with_outputs", HF_FLAG_EXT, 0 }, + { "gnu_asm_goto_with_outputs_full", HF_FLAG_EXT, 0 } +}; + /* Global visibility options. */ struct visibility_flags visibility_options; @@ -9545,4 +9573,25 @@ c_strict_flex_array_level_of (tree array_field) return strict_flex_array_level; } +bool +has_generic_feature_p (const char *feat, bool strict_p) +{ + for (unsigned i = 0; i < ARRAY_SIZE (has_feature_table); i++) + { + const hf_feature_info *info = has_feature_table + i; + if (strcmp (info->ident, feat)) + continue; + + if ((info->flags & HF_FLAG_EXT) && strict_p) + return false; + + if (info->flags & HF_FLAG_SANITIZE) + return flag_sanitize & info->mask; + + return true; + } + + return has_lang_feature_p (feat, strict_p); +} + #include "gt-c-family-c-common.h" diff --git a/gcc/c-family/c-common.h b/gcc/c-family/c-common.h index f96350b64af..38fd30312a0 100644 --- a/gcc/c-family/c-common.h +++ b/gcc/c-family/c-common.h @@ -1121,6 +1121,9 @@ extern bool c_cpp_diagnostic (cpp_reader *, enum cpp_diagnostic_level, ATTRIBUTE_GCC_DIAG(5,0); extern int c_common_has_attribute (cpp_reader *, bool); extern int c_common_has_builtin (cpp_reader *); +extern int c_common_has_feature (cpp_reader *, bool); +extern bool has_generic_feature_p (const char *, bool); +extern bool has_lang_feature_p (const char *, bool); extern bool parse_optimize_options (tree, bool); diff --git a/gcc/c-family/c-lex.cc b/gcc/c-family/c-lex.cc index 6eb0fae2f53..3301d90d6ab 100644 --- a/gcc/c-family/c-lex.cc +++ b/gcc/c-family/c-lex.cc @@ -82,6 +82,7 @@ init_c_lex (void) cb->read_pch = c_common_read_pch; cb->has_attribute = c_common_has_attribute; cb->has_builtin = c_common_has_builtin; + cb->has_feature = c_common_has_feature; cb->get_source_date_epoch = cb_get_source_date_epoch; cb->get_suggestion = cb_get_suggestion; cb->remap_filename = remap_macro_filename; @@ -429,16 +430,16 @@ c_common_has_attribute (cpp_reader *pfile, bool std_syntax) return result; } -/* Callback for has_builtin. */ +/* Helper for __has_{builtin,feature,extension}. */ -int -c_common_has_builtin (cpp_reader *pfile) +static const char * +c_common_lex_availability_macro (cpp_reader *pfile, const char *builtin) { const cpp_token *token = get_token_no_padding (pfile); if (token->type != CPP_OPEN_PAREN) { cpp_error (pfile, CPP_DL_ERROR, - "missing '(' after \"__has_builtin\""); + "missing '(' after \"__has_%s\"", builtin); return 0; } @@ -458,7 +459,7 @@ c_common_has_builtin (cpp_reader *pfile) else { cpp_error (pfile, CPP_DL_ERROR, - "macro \"__has_builtin\" requires an identifier"); + "macro \"__has_%s\" requires an identifier", builtin); if (token->type == CPP_CLOSE_PAREN) return 0; } @@ -477,9 +478,35 @@ c_common_has_builtin (cpp_reader *pfile) break; } + return name; +} + +/* Callback for has_builtin. */ + +int +c_common_has_builtin (cpp_reader *pfile) +{ + const char *name = c_common_lex_availability_macro (pfile, "builtin"); + if (!name) + return 0; + return names_builtin_p (name); } +/* Callback for has_feature. STRICT_P is true for has_feature and false + for has_extension. */ + +int +c_common_has_feature (cpp_reader *pfile, bool strict_p) +{ + const char *builtin = strict_p ? "feature" : "extension"; + const char *name = c_common_lex_availability_macro (pfile, builtin); + if (!name) + return 0; + + return has_generic_feature_p (name, strict_p); +} + /* Read a token and return its type. Fill *VALUE with its value, if applicable. Fill *CPP_FLAGS with the token's flags, if it is diff --git a/gcc/c-family/c-ppoutput.cc b/gcc/c-family/c-ppoutput.cc index 4aa2bef2c0f..a1488c6f086 100644 --- a/gcc/c-family/c-ppoutput.cc +++ b/gcc/c-family/c-ppoutput.cc @@ -162,6 +162,7 @@ init_pp_output (FILE *out_stream) cb->has_attribute = c_common_has_attribute; cb->has_builtin = c_common_has_builtin; + cb->has_feature = c_common_has_feature; cb->get_source_date_epoch = cb_get_source_date_epoch; cb->remap_filename = remap_macro_filename; diff --git a/gcc/c/c-objc-common.cc b/gcc/c/c-objc-common.cc index e4aed61ed00..30e6c491421 100644 --- a/gcc/c/c-objc-common.cc +++ b/gcc/c/c-objc-common.cc @@ -34,6 +34,48 @@ along with GCC; see the file COPYING3. If not see static bool c_tree_printer (pretty_printer *, text_info *, const char *, int, bool, bool, bool, bool *, const char **); +struct c_feature_info +{ + const char *ident; + const int *enable_flag; +}; + +static const c_feature_info c_feature_table[] = +{ + { "c_alignas", &flag_isoc11 }, + { "c_alignof", &flag_isoc11 }, + { "c_atomic", &flag_isoc11 }, + { "c_generic_selections", &flag_isoc11 }, + { "c_static_assert", &flag_isoc11 }, + { "c_thread_local", &flag_isoc11 }, + + /* XXX: Binary literals are available as a standard feature in + C2x. They are standardised in C++14 and available as an extension + in all C versions. Would it make more sense to have + cxx_binary_literals always report as an extension (in C) and add a + new c_binary_literals that reports as a feature for -std=c2x and an + extension below that? */ + { "cxx_binary_literals", &flag_isoc2x } +}; + +bool +has_lang_feature_p (const char *feat, bool strict_p) +{ + for (unsigned i = 0; i < ARRAY_SIZE (c_feature_table); i++) + { + const c_feature_info *info = c_feature_table + i; + if (strcmp (info->ident, feat)) + continue; + + if (info->enable_flag && strict_p && !*info->enable_flag) + return false; + + return true; + } + + return false; +} + bool c_missing_noreturn_ok_p (tree decl) { diff --git a/gcc/cp/cp-objcp-common.cc b/gcc/cp/cp-objcp-common.cc index 93b027b80ce..494f72b5ca1 100644 --- a/gcc/cp/cp-objcp-common.cc +++ b/gcc/cp/cp-objcp-common.cc @@ -23,10 +23,127 @@ along with GCC; see the file COPYING3. If not see #include "coretypes.h" #include "cp-tree.h" #include "cp-objcp-common.h" +#include "c-family/c-common.h" #include "dwarf2.h" #include "stringpool.h" #include "contracts.h" +struct cp_feature_selector +{ + enum + { + DIALECT, + FLAG + } kind; + + union + { + const int *enable_flag; + struct { + enum cxx_dialect feat; + enum cxx_dialect ext; + } dialect; + }; + + constexpr cp_feature_selector (const int *flag) + : kind (FLAG), enable_flag (flag) {} + constexpr cp_feature_selector (enum cxx_dialect feat, + enum cxx_dialect ext) + : kind (DIALECT), dialect{feat, ext} {} + constexpr cp_feature_selector (enum cxx_dialect feat) + : cp_feature_selector (feat, feat) {} + + bool has_feature (bool strict_p) const; +}; + +bool cp_feature_selector::has_feature (bool strict_p) const +{ + switch (kind) + { + case DIALECT: + if (!strict_p) + return cxx_dialect >= dialect.ext; + return cxx_dialect >= dialect.feat; + case FLAG: + return *enable_flag; + } + gcc_unreachable (); +} + +struct cp_feature_info +{ + const char *ident; + cp_feature_selector selector; +}; + +static const cp_feature_info cp_feature_table[] = +{ + { "cxx_exceptions", &flag_exceptions }, + { "cxx_rtti", &flag_rtti }, + { "cxx_access_control_sfinae", { cxx11, cxx98 } }, + { "cxx_alias_templates", cxx11 }, + { "cxx_alignas", cxx11 }, + { "cxx_alignof", cxx11 }, + { "cxx_attributes", cxx11 }, + { "cxx_constexpr", cxx11 }, + { "cxx_constexpr_string_builtins", cxx11 }, + { "cxx_decltype", cxx11 }, + { "cxx_decltype_incomplete_return_types", cxx11 }, + { "cxx_default_function_template_args", cxx11 }, + { "cxx_defaulted_functions", cxx11 }, /* XXX: extension in c++98? */ + { "cxx_delegating_constructors", { cxx11, cxx98 } }, + { "cxx_deleted_functions", cxx11 }, + { "cxx_explicit_conversions", { cxx11, cxx98 } }, + { "cxx_generalized_initializers", cxx11 }, + { "cxx_implicit_moves", cxx11 }, + { "cxx_inheriting_constructors", cxx11 }, /* XXX: extension in c++98? */ + { "cxx_inline_namespaces", { cxx11, cxx98 } }, + { "cxx_lambdas", cxx11 }, /* XXX: extension in c++98? */ + { "cxx_local_type_template_args", cxx11 }, + { "cxx_noexcept", cxx11 }, + { "cxx_nonstatic_member_init", { cxx11, cxx98 } }, + { "cxx_nullptr", cxx11 }, + { "cxx_override_control", { cxx11, cxx98 } }, + { "cxx_reference_qualified_functions", cxx11 }, + { "cxx_range_for", cxx11 }, + { "cxx_raw_string_literals", cxx11 }, + { "cxx_rvalue_references", cxx11 }, + { "cxx_static_assert", cxx11 }, + { "cxx_thread_local", cxx11 }, + { "cxx_auto_type", cxx11 }, + { "cxx_strong_enums", cxx11 }, + { "cxx_trailing_return", cxx11 }, + { "cxx_unicode_literals", cxx11 }, + { "cxx_unrestricted_unions", cxx11 }, + { "cxx_user_literals", cxx11 }, + { "cxx_variadic_templates", { cxx11, cxx98 } }, + { "cxx_binary_literals", { cxx14, cxx98 } }, + { "cxx_contextual_conversions", { cxx14, cxx98 } }, + { "cxx_decltype_auto", cxx14 }, + { "cxx_aggregate_nsdmi", cxx14 }, + { "cxx_init_captures", { cxx14, cxx11 } }, + { "cxx_generic_lambdas", cxx14 }, + { "cxx_relaxed_constexpr", cxx14 }, + { "cxx_return_type_deduction", cxx14 }, + { "cxx_variable_templates", { cxx14, cxx98 } }, + { "modules", &flag_modules }, +}; + +bool +has_lang_feature_p (const char *feat, bool strict_p) +{ + for (unsigned i = 0; i < ARRAY_SIZE (cp_feature_table); i++) + { + const cp_feature_info *info = cp_feature_table + i; + if (strcmp (info->ident, feat)) + continue; + + return info->selector.has_feature (strict_p); + } + + return false; +} + /* Special routine to get the alias set for C++. */ alias_set_type diff --git a/gcc/doc/cpp.texi b/gcc/doc/cpp.texi index b0a2ce3ac6b..9ed96786249 100644 --- a/gcc/doc/cpp.texi +++ b/gcc/doc/cpp.texi @@ -3198,6 +3198,8 @@ directive}: @samp{#if}, @samp{#ifdef} or @samp{#ifndef}. * @code{__has_cpp_attribute}:: * @code{__has_c_attribute}:: * @code{__has_builtin}:: +* @code{__has_feature}:: +* @code{__has_extension}:: * @code{__has_include}:: @end menu @@ -3560,6 +3562,30 @@ the operator is as follows: #endif @end smallexample +@node @code{__has_feature} +@subsection @code{__has_feature} +@cindex @code{__has_feature} + +The special operator @code{__has_feature (@var{operand})} may be used in +constant integer contexts and in preprocessor @samp{#if} and @samp{#elif} +expressions to test whether the identifier given in @var{operand} is recognized +as a feature supported by GCC given the current options and, in the case of +standard language features, whether the feature is available in the chosen +version of the language standard. + +@node @code{__has_extension} +@subsection @code{__has_extension} +@cindex @code{__has_extension} + +The special operator @code{__has_extension (@var{operand})} may be used in +constant integer contexts and in preprocessor @samp{#if} and @samp{#elif} +expressions to test whether the identifier given in @var{operand} is recognized +as an extension supported by GCC given the current options. In any given +context, the features accepted by @code{__has_extension} are a strict superset +of those accepted by @code{__has_feature}. Unlike @code{__has_feature}, +@code{__has_extension} tests whether a given feature is available regardless of +strict language standards conformance. + @node @code{__has_include} @subsection @code{__has_include} @cindex @code{__has_include} diff --git a/gcc/testsuite/c-c++-common/has-feature-common.c b/gcc/testsuite/c-c++-common/has-feature-common.c new file mode 100644 index 00000000000..9a57b11e8e2 --- /dev/null +++ b/gcc/testsuite/c-c++-common/has-feature-common.c @@ -0,0 +1,57 @@ +/* { dg-do compile } */ +/* Test __has_{feature,extension} for generic features. */ + +#define FEAT(x) (__has_feature (x) && __has_extension (x)) +#define EXT(x) (__has_extension (x) && !__has_feature (x)) + +#if __has_feature (unknown_feature) || __has_extension (unknown_feature) +#error unknown feature is known! +#endif + +#if !__has_extension (gnu_asm_goto_with_outputs) +#error +#endif + +#if !EXT (gnu_asm_goto_with_outputs) +#error +#endif + +#if !EXT (gnu_asm_goto_with_outputs_full) +#error +#endif + +#if !FEAT (enumerator_attributes) +#error +#endif + +#if !FEAT (attribute_deprecated_with_message) +#error +#endif + +#if !FEAT (attribute_unavailable_with_message) +#error +#endif + +#if !FEAT (enumerator_attributes) +#error +#endif + +#if !FEAT (tls) +#error +#endif + +#if defined (__SANITIZE_ADDRESS__) != __has_feature (address_sanitizer) +#error +#endif + +#if defined (__SANITIZE_ADDRESS__) != __has_extension (address_sanitizer) +#error +#endif + +#if defined (__SANITIZE_THREAD__) != __has_feature (thread_sanitizer) +#error +#endif + +#if defined (__SANITIZE_THREAD__) != __has_extension (thread_sanitizer) +#error +#endif diff --git a/gcc/testsuite/g++.dg/ext/has-feature.C b/gcc/testsuite/g++.dg/ext/has-feature.C new file mode 100644 index 00000000000..58d0057c30d --- /dev/null +++ b/gcc/testsuite/g++.dg/ext/has-feature.C @@ -0,0 +1,225 @@ +// { dg-do compile } + +#define FEAT(x) (__has_feature(x) && __has_extension(x)) +#define CXX11 (__cplusplus >= 201103L) +#define CXX14 (__cplusplus >= 201402L) + +#if !FEAT(cxx_exceptions) || !FEAT(cxx_rtti) +#error +#endif + +#if __has_feature (cxx_access_control_sfinae) != CXX11 +#error +#endif + +#if !__has_extension (cxx_access_control_sfinae) +#error +#endif + +#if FEAT(cxx_alias_templates) != CXX11 +#error +#endif + +#if FEAT(cxx_alignas) != CXX11 +#error +#endif + +#if FEAT(cxx_alignof) != CXX11 +#error +#endif + +#if FEAT(cxx_attributes) != CXX11 +#error +#endif + +#if FEAT(cxx_constexpr) != CXX11 +#error +#endif + +#if FEAT(cxx_decltype) != CXX11 +#error +#endif + +#if FEAT(cxx_decltype_incomplete_return_types) != CXX11 +#error +#endif + +#if FEAT(cxx_default_function_template_args) != CXX11 +#error +#endif + +#if FEAT(cxx_defaulted_functions) != CXX11 +#error +#endif + +#if !__has_extension (cxx_delegating_constructors) +#error +#endif + +#if __has_feature (cxx_delegating_constructors) != CXX11 +#error +#endif + +#if FEAT (cxx_deleted_functions) != CXX11 +#error +#endif + +#if !__has_extension (cxx_explicit_conversions) +#error +#endif + +#if __has_feature (cxx_explicit_conversions) != CXX11 +#error +#endif + +#if FEAT (cxx_generalized_initializers) != CXX11 +#error +#endif + +#if FEAT (cxx_implicit_moves) != CXX11 +#error +#endif + +#if FEAT (cxx_inheriting_constructors) != CXX11 +#error +#endif + +#if !__has_extension (cxx_inline_namespaces) +#error +#endif + +#if __has_feature (cxx_inline_namespaces) != CXX11 +#error +#endif + +#if FEAT (cxx_lambdas) != CXX11 +#error +#endif + +#if FEAT (cxx_local_type_template_args) != CXX11 +#error +#endif + +#if FEAT (cxx_noexcept) != CXX11 +#error +#endif + +#if !__has_extension (cxx_nonstatic_member_init) +#error +#endif + +#if __has_feature (cxx_nonstatic_member_init) != CXX11 +#error +#endif + +#if FEAT (cxx_nullptr) != CXX11 +#error +#endif + +#if !__has_extension (cxx_override_control) +#error +#endif + +#if __has_feature (cxx_override_control) != CXX11 +#error +#endif + +#if FEAT (cxx_reference_qualified_functions) != CXX11 +#error +#endif + +#if FEAT (cxx_range_for) != CXX11 +#error +#endif + +#if FEAT (cxx_raw_string_literals) != CXX11 +#error +#endif + +#if FEAT (cxx_rvalue_references) != CXX11 +#error +#endif + +#if FEAT (cxx_static_assert) != CXX11 +#error +#endif + +#if FEAT (cxx_thread_local) != CXX11 +#error +#endif + +#if FEAT (cxx_auto_type) != CXX11 +#error +#endif + +#if FEAT (cxx_strong_enums) != CXX11 +#error +#endif + +#if FEAT (cxx_trailing_return) != CXX11 +#error +#endif + +#if FEAT (cxx_unicode_literals) != CXX11 +#error +#endif + +#if FEAT (cxx_unrestricted_unions) != CXX11 +#error +#endif + +#if FEAT (cxx_user_literals) != CXX11 +#error +#endif + +#if !__has_extension (cxx_variadic_templates) +#error +#endif + +#if __has_feature (cxx_variadic_templates) != CXX11 +#error +#endif + +#if !__has_extension (cxx_binary_literals) +#error +#endif + +#if __has_feature (cxx_binary_literals) != CXX14 +#error +#endif + +#if FEAT (cxx_decltype_auto) != CXX14 +#error +#endif + +#if FEAT (cxx_aggregate_nsdmi) != CXX14 +#error +#endif + +#if __has_extension (cxx_init_captures) != CXX11 +#error +#endif + +#if __has_feature (cxx_init_captures) != CXX14 +#error +#endif + +#if FEAT (cxx_generic_lambdas) != CXX14 +#error +#endif + +#if FEAT (cxx_relaxed_constexpr) != CXX14 +#error +#endif + +#if FEAT (cxx_return_type_deduction) != CXX14 +#error +#endif + +#if !__has_extension (cxx_variable_templates) +#error +#endif + +#if __has_feature (cxx_variable_templates) != CXX14 +#error +#endif diff --git a/gcc/testsuite/gcc.dg/asan/has-feature-asan.c b/gcc/testsuite/gcc.dg/asan/has-feature-asan.c new file mode 100644 index 00000000000..810b69b8fc8 --- /dev/null +++ b/gcc/testsuite/gcc.dg/asan/has-feature-asan.c @@ -0,0 +1,6 @@ +/* { dg-do compile } */ +/* { dg-options "-fsanitize=address" } */ +#define FEAT(x) (__has_feature (x) && __has_extension (x)) +#if !FEAT (address_sanitizer) +#error +#endif diff --git a/gcc/testsuite/gcc.dg/has-feature.c b/gcc/testsuite/gcc.dg/has-feature.c new file mode 100644 index 00000000000..19d27699a92 --- /dev/null +++ b/gcc/testsuite/gcc.dg/has-feature.c @@ -0,0 +1,63 @@ +/* { dg-do compile } */ +/* Test __has_{feature,extension} for C language features. */ + +#if !__has_extension (c_alignas) || !__has_extension (c_alignof) +#error +#endif + +#if !__has_extension (c_atomic) || !__has_extension (c_generic_selections) +#error +#endif + +#if !__has_extension (c_static_assert) || !__has_extension (c_thread_local) +#error +#endif + +#if !__has_extension (cxx_binary_literals) +#error +#endif + +#if __STDC_VERSION__ >= 201112L +/* Have C11 features. */ +#if !__has_feature (c_alignas) || !__has_feature (c_alignof) +#error +#endif + +#if !__has_feature (c_atomic) || !__has_feature (c_generic_selections) +#error +#endif + +#if !__has_feature (c_static_assert) || !__has_feature (c_thread_local) +#error +#endif + +#else +/* Don't have C11 features. */ +#if __has_feature (c_alignas) || __has_feature (c_alignof) +#error +#endif + +#if __has_feature (c_atomic) || __has_feature (c_generic_selections) +#error +#endif + +#if __has_feature (c_static_assert) || __has_feature (c_thread_local) +#error +#endif + +#endif + +#if __STDC_VERSION__ >= 202000L +/* Have C2x features. */ +#if !__has_feature (cxx_binary_literals) +#error +#endif + +#else +/* Don't have C2x features. */ +#if __has_feature (cxx_binary_literals) +#error +#endif +#endif + +enum { just_here_to_make_this_tu_nonempty }; diff --git a/gcc/testsuite/gcc.dg/ubsan/has-feature-ubsan.c b/gcc/testsuite/gcc.dg/ubsan/has-feature-ubsan.c new file mode 100644 index 00000000000..e5da1cc5628 --- /dev/null +++ b/gcc/testsuite/gcc.dg/ubsan/has-feature-ubsan.c @@ -0,0 +1,6 @@ +/* { dg-do compile } */ +/* { dg-options "-fsanitize=undefined" } */ +#define FEAT(x) (__has_feature (x) && __has_extension (x)) +#if !FEAT (undefined_behavior_sanitizer) +#error +#endif diff --git a/libcpp/include/cpplib.h b/libcpp/include/cpplib.h index a6f0abd894c..8f39a6a3a66 100644 --- a/libcpp/include/cpplib.h +++ b/libcpp/include/cpplib.h @@ -755,6 +755,9 @@ struct cpp_callbacks /* Callback to determine whether a built-in function is recognized. */ int (*has_builtin) (cpp_reader *); + /* Callback to determine whether a feature is available. */ + int (*has_feature) (cpp_reader *, bool); + /* Callback that can change a user lazy into normal macro. */ void (*user_lazy_macro) (cpp_reader *, cpp_macro *, unsigned); @@ -959,7 +962,9 @@ enum cpp_builtin_type BT_HAS_STD_ATTRIBUTE, /* `__has_c_attribute(x)' */ BT_HAS_BUILTIN, /* `__has_builtin(x)' */ BT_HAS_INCLUDE, /* `__has_include(x)' */ - BT_HAS_INCLUDE_NEXT /* `__has_include_next(x)' */ + BT_HAS_INCLUDE_NEXT, /* `__has_include_next(x)' */ + BT_HAS_FEATURE, /* `__has_feature(x)' */ + BT_HAS_EXTENSION /* `__has_extension(x)' */ }; #define CPP_HASHNODE(HNODE) ((cpp_hashnode *) (HNODE)) diff --git a/libcpp/init.cc b/libcpp/init.cc index c508f06112a..465dafefe9d 100644 --- a/libcpp/init.cc +++ b/libcpp/init.cc @@ -433,6 +433,8 @@ static const struct builtin_macro builtin_array[] = B("__has_builtin", BT_HAS_BUILTIN, true), B("__has_include", BT_HAS_INCLUDE, true), B("__has_include_next",BT_HAS_INCLUDE_NEXT, true), + B("__has_feature", BT_HAS_FEATURE, true), + B("__has_extension", BT_HAS_EXTENSION, true), /* Keep builtins not used for -traditional-cpp at the end, and update init_builtins() if any more are added. */ B("_Pragma", BT_PRAGMA, true), diff --git a/libcpp/macro.cc b/libcpp/macro.cc index d4238d4f621..d2e8f9bd411 100644 --- a/libcpp/macro.cc +++ b/libcpp/macro.cc @@ -677,6 +677,12 @@ _cpp_builtin_macro_text (cpp_reader *pfile, cpp_hashnode *node, number = builtin_has_include (pfile, node, node->value.builtin == BT_HAS_INCLUDE_NEXT); break; + + case BT_HAS_FEATURE: + case BT_HAS_EXTENSION: + number = pfile->cb.has_feature (pfile, + node->value.builtin == BT_HAS_FEATURE); + break; } if (result == NULL)