c-family: Implement __has_feature and __has_extension [PR60512]
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 exception
of the legacy features for C++ type traits. These are omitted, since as
the clang documentation notes, __has_builtin is the correct "modern" way
to query for these (which GCC already implements).
gcc/c-family/ChangeLog:
PR c++/60512
* c-common.cc (struct hf_feature_info): New.
(c_common_register_feature): New.
(init_has_feature): New.
(has_feature_p): New.
* c-common.h (c_common_has_feature): New.
(c_family_register_lang_features): New.
(c_common_register_feature): New.
(has_feature_p): New.
* c-lex.cc (init_c_lex): Plumb through has_feature callback.
(c_common_has_builtin): Generalize and move common part ...
(c_common_lex_availability_macro): ... here.
(c_common_has_feature): New.
* c-ppoutput.cc (init_pp_output): Plumb through has_feature.
gcc/c/ChangeLog:
PR c++/60512
* c-lang.cc (c_family_register_lang_features): New.
* c-objc-common.cc (struct c_feature_info): New.
(c_register_features): New.
* c-objc-common.h (c_register_features): New.
gcc/cp/ChangeLog:
PR c++/60512
* cp-lang.cc (c_family_register_lang_features): New.
* cp-objcp-common.cc (struct cp_feature_selector): New.
(cp_feature_selector::has_feature): New.
(struct cp_feature_info): New.
(cp_register_features): New.
* cp-objcp-common.h (cp_register_features): New.
gcc/ChangeLog:
PR c++/60512
* doc/cpp.texi: Document __has_{feature,extension}.
gcc/objc/ChangeLog:
PR c++/60512
* objc-act.cc (struct objc_feature_info): New.
(objc_nonfragile_abi_p): New.
(objc_common_register_features): New.
* objc-act.h (objc_common_register_features): New.
* objc-lang.cc (c_family_register_lang_features): New.
gcc/objcp/ChangeLog:
PR c++/60512
* objcp-lang.cc (c_family_register_lang_features): New.
libcpp/ChangeLog:
PR c++/60512
* include/cpplib.h (struct cpp_callbacks): Add has_feature.
(enum cpp_builtin_type): Add BT_HAS_{FEATURE,EXTENSION}.
* init.cc: Add __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.
* c-c++-common/has-feature-pedantic.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.
* gcc.dg/ubsan/has-feature-ubsan.c: New test.
* obj-c++.dg/has-feature.mm: New test.
* objc.dg/has-feature.m: New test.
Co-Authored-By: Iain Sandoe <iain@sandoe.co.uk>
06280a906c