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| author | Joseph Myers <joseph@codesourcery.com> | 2020-11-04 06:48:46 +0000 |
|---|---|---|
| committer | Joseph Myers <joseph@codesourcery.com> | 2020-11-04 06:48:46 +0000 |
| commit | c19e44ac8dbc9af07e5e671edfa03ab5b08649c5 (patch) | |
| tree | 042ddbf096456fbd03cf55ccbc034a061ffea5df /gcc/c/c-parser.c | |
| parent | 2e0aa43fc6ae689c595902310baec604e7e0d695 (diff) | |
| download | gcc-c19e44ac8dbc9af07e5e671edfa03ab5b08649c5.zip gcc-c19e44ac8dbc9af07e5e671edfa03ab5b08649c5.tar.gz gcc-c19e44ac8dbc9af07e5e671edfa03ab5b08649c5.tar.bz2 | |
c: Implement C2x nodiscard attribute
C2x adds the nodiscard standard attribute, with an optional string
argument, as in C++; implement it for C.
Bootstrapped with no regressions for x86_64-pc-linux-gnu.
gcc/c/
2020-11-04 Joseph Myers <joseph@codesourcery.com>
* c-decl.c (handle_nodiscard_attribute): New.
(std_attribute_table): Add nodiscard.
* c-parser.c (c_parser_std_attribute): Expect argument to
nodiscard attribute to be a string. Do not special-case ignoring
nodiscard.
* c-typeck.c (maybe_warn_nodiscard): New.
(build_compound_expr, emit_side_effect_warnings): Call
maybe_warn_nodiscard.
(c_process_expr_stmt, c_finish_stmt_expr): Also call
emit_side_effect_warnings if warn_unused_result.
gcc/testsuite/
2020-11-04 Joseph Myers <joseph@codesourcery.com>
* gcc.dg/c2x-attr-nodiscard-1.c, gcc.dg/c2x-attr-nodiscard-2.c,
gcc.dg/c2x-attr-nodiscard-3.c, gcc.dg/c2x-attr-nodiscard-4.c: New
tests.
* gcc.dg/c2x-attr-syntax-5.c: Remove nodiscard test.
Diffstat (limited to 'gcc/c/c-parser.c')
| -rw-r--r-- | gcc/c/c-parser.c | 10 |
1 files changed, 5 insertions, 5 deletions
diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c index b921c4e..fc97aa3 100644 --- a/gcc/c/c-parser.c +++ b/gcc/c/c-parser.c @@ -4950,7 +4950,8 @@ c_parser_std_attribute (c_parser *parser, bool for_tm) && attribute_takes_identifier_p (name)); bool require_string = (ns == NULL_TREE - && strcmp (IDENTIFIER_POINTER (name), "deprecated") == 0); + && (strcmp (IDENTIFIER_POINTER (name), "deprecated") == 0 + || strcmp (IDENTIFIER_POINTER (name), "nodiscard") == 0)); TREE_VALUE (attribute) = c_parser_attribute_arguments (parser, takes_identifier, require_string, false); @@ -4960,13 +4961,12 @@ c_parser_std_attribute (c_parser *parser, bool for_tm) parens.require_close (parser); } out: - if (ns == NULL_TREE && !for_tm && !as && !is_attribute_p ("nodiscard", name)) + if (ns == NULL_TREE && !for_tm && !as) { /* An attribute with standard syntax and no namespace specified is a constraint violation if it is not one of the known - standard attributes (of which nodiscard is the only one - without a handler in GCC). Diagnose it here with a pedwarn - and then discard it to prevent a duplicate warning later. */ + standard attributes. Diagnose it here with a pedwarn and + then discard it to prevent a duplicate warning later. */ pedwarn (input_location, OPT_Wattributes, "%qE attribute ignored", name); return error_mark_node; |