From 93313b94fe18f3c3de4f24f5bb3fafb4639f1c7e Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Wed, 2 Oct 2019 01:08:40 +0100 Subject: Handle :: tokens in C for C2x. As part of adding [[]]-style attributes, C2x adds the token :: for use in scoped attribute names. This patch adds corresponding support for that token in C to GCC. The token is supported both for C2x and for older gnu* standards (on the basis that extensions are normally supported in older gnu* versions; people will expect to be able to use [[]] attributes, before C2x is the default, without needing to use -std=gnu2x). There are no cases in older C standards where the token : can be followed by a token starting with : in syntactically valid sources; the only cases the :: token could break in older standard C thus are ones involving concatenation of pp-tokens where the result does not end up as tokens (e.g., gets stringized). In GNU C extensions, the main case where :: might appear in existing sources is in asm statements, and the C parser is thus made to handle it like two consecutive : tokens, which the C++ parser already does. A limited test of various positionings of :: in asm statements is added to the testsuite (in particular, to cover the syntax error when :: means too many colons but a single : would be OK), but existing tests cover a variety of styles there anyway. Technically there are cases in Objective-C and OpenMP for which this also changes how previously valid code is lexed: the objc-selector-arg syntax allows multiple consecutive : tokens (although I don't think they are particularly useful there), while OpenMP syntax includes array section syntax such as [:] which, before :: was a token, could also be written as [::> (there might be other OpenMP cases potentially affected, I didn't check all the OpenMP syntax in detail). I don't think either of those cases affects the basis for supporting the :: token in all -std=gnu* modes, or that there is any obvious need to special-case handling of CPP_SCOPE tokens for those constructs the way there is for asm statements. cpp_avoid_paste, which determines when spaces need adding between tokens in preprocessed output where there wouldn't otherwise be whitespace between them (e.g. if stringized), already inserts space between : and : unconditionally, rather than only for C++, so no change is needed there (but a C2x test is added that such space is indeed inserted). Bootstrapped with no regressions on x86-64-pc-linux-gnu. gcc/c: * c-parser.c (c_parser_asm_statement): Handle CPP_SCOPE like two CPP_COLON tokens. gcc/testsuite: * gcc.dg/asm-scope-1.c, gcc.dg/cpp/c11-scope-1.c, gcc.dg/cpp/c17-scope-1.c, gcc.dg/cpp/c2x-scope-1.c, gcc.dg/cpp/c2x-scope-2.c, gcc.dg/cpp/c90-scope-1.c, gcc.dg/cpp/c94-scope-1.c, gcc.dg/cpp/c99-scope-1.c, gcc.dg/cpp/gnu11-scope-1.c, gcc.dg/cpp/gnu17-scope-1.c, gcc.dg/cpp/gnu89-scope-1.c, gcc.dg/cpp/gnu99-scope-1.c: New tests. libcpp: * include/cpplib.h (struct cpp_options): Add member scope. * init.c (struct lang_flags, lang_defaults): Likewise. (cpp_set_lang): Set scope member of pfile. * lex.c (_cpp_lex_direct): Test CPP_OPTION (pfile, scope) not CPP_OPTION (pfile, cplusplus) for creating CPP_SCOPE tokens. From-SVN: r276434 --- gcc/c/ChangeLog | 5 +++++ gcc/c/c-parser.c | 25 +++++++++++++++++++------ 2 files changed, 24 insertions(+), 6 deletions(-) (limited to 'gcc/c') diff --git a/gcc/c/ChangeLog b/gcc/c/ChangeLog index 3156e35..0f263f7 100644 --- a/gcc/c/ChangeLog +++ b/gcc/c/ChangeLog @@ -1,3 +1,8 @@ +2019-10-02 Joseph Myers + + * c-parser.c (c_parser_asm_statement): Handle CPP_SCOPE like two + CPP_COLON tokens. + 2019-10-01 Richard Sandiford * c-objc-common.c (useful_aka_type_p): New function. diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c index c8afab2..6957297 100644 --- a/gcc/c/c-parser.c +++ b/gcc/c/c-parser.c @@ -6411,7 +6411,9 @@ c_parser_for_statement (c_parser *parser, bool ivdep, unsigned short unroll, The form with asm-goto-operands is valid if and only if the asm-qualifier-list contains goto, and is the only allowed form in that case. - Duplicate asm-qualifiers are not allowed. */ + Duplicate asm-qualifiers are not allowed. + + The :: token is considered equivalent to two consecutive : tokens. */ static tree c_parser_asm_statement (c_parser *parser) @@ -6509,17 +6511,28 @@ c_parser_asm_statement (c_parser *parser) nsections = 3 + is_goto; for (section = 0; section < nsections; ++section) { - if (!c_parser_require (parser, CPP_COLON, - is_goto - ? G_("expected %<:%>") - : G_("expected %<:%> or %<)%>"), - UNKNOWN_LOCATION, is_goto)) + if (c_parser_next_token_is (parser, CPP_SCOPE)) + { + ++section; + if (section == nsections) + { + c_parser_error (parser, "expected %<)%>"); + goto error_close_paren; + } + c_parser_consume_token (parser); + } + else if (!c_parser_require (parser, CPP_COLON, + is_goto + ? G_("expected %<:%>") + : G_("expected %<:%> or %<)%>"), + UNKNOWN_LOCATION, is_goto)) goto error_close_paren; /* Once past any colon, we're no longer a simple asm. */ simple = false; if ((!c_parser_next_token_is (parser, CPP_COLON) + && !c_parser_next_token_is (parser, CPP_SCOPE) && !c_parser_next_token_is (parser, CPP_CLOSE_PAREN)) || section == 3) switch (section) -- cgit v1.1