On Mon, Oct 11, 2021 at 11:19 AM Marek Polacek via Gcc-patches <gcc-patches@gcc.gnu.org> wrote: > > Any thoughts?
I think it's a good idea, but then again I can't approve it, so... well, who can, then? > > On Thu, Sep 23, 2021 at 12:16:36PM -0400, Marek Polacek via Gcc-patches wrote: > > Clang implements something we don't have: > > > > __attribute__((deprecated("message", "replacement"))); > > > > which seems pretty neat so I wrote this patch to add it to gcc. > > > > It doesn't allow the optional second argument in the standard [[]] > > form so as not to clash with possible future standard additions. > > > > I had hoped we could print a nice fix-it replacement hint, but that > > won't be possible until warn_deprecated_use gets something better than > > input_location. Looking forward to the fix-it hint support being added! > > > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? > > > > PR c++/102049 > > > > gcc/c-family/ChangeLog: > > > > * c-attribs.c (c_common_attribute_table): Increase max_len for > > deprecated. > > (handle_deprecated_attribute): Allow an optional second argument > > in the GNU form of attribute deprecated. > > > > gcc/c/ChangeLog: > > > > * c-parser.c (c_parser_std_attribute): Give a diagnostic when > > the standard form of an attribute deprecated has a second argument. > > > > gcc/ChangeLog: > > > > * doc/extend.texi: Document attribute deprecated with an > > optional second argument. > > * tree.c (warn_deprecated_use): Print the replacement argument, > > if any. > > > > gcc/testsuite/ChangeLog: > > > > * gcc.dg/c2x-attr-deprecated-3.c: Adjust dg-error. > > * c-c++-common/Wdeprecated-arg-1.c: New test. > > --- > > gcc/c-family/c-attribs.c | 17 ++++++++++++- > > gcc/c/c-parser.c | 8 ++++++ > > gcc/doc/extend.texi | 24 ++++++++++++++++++ > > .../c-c++-common/Wdeprecated-arg-1.c | 21 ++++++++++++++++ > > gcc/testsuite/gcc.dg/c2x-attr-deprecated-3.c | 2 +- > > gcc/tree.c | 25 +++++++++++++++---- > > 6 files changed, 90 insertions(+), 7 deletions(-) > > create mode 100644 gcc/testsuite/c-c++-common/Wdeprecated-arg-1.c > > > > diff --git a/gcc/c-family/c-attribs.c b/gcc/c-family/c-attribs.c > > index 007b928c54b..ef857a9ae2c 100644 > > --- a/gcc/c-family/c-attribs.c > > +++ b/gcc/c-family/c-attribs.c > > @@ -409,7 +409,7 @@ const struct attribute_spec c_common_attribute_table[] = > > to prevent its usage in source code. */ > > { "no vops", 0, 0, true, false, false, false, > > handle_novops_attribute, NULL }, > > - { "deprecated", 0, 1, false, false, false, false, > > + { "deprecated", 0, 2, false, false, false, false, > > handle_deprecated_attribute, NULL }, > > { "unavailable", 0, 1, false, false, false, false, > > handle_unavailable_attribute, NULL }, > > @@ -4107,6 +4107,21 @@ handle_deprecated_attribute (tree *node, tree name, > > error ("deprecated message is not a string"); > > *no_add_attrs = true; > > } > > + else if (TREE_CHAIN (args) != NULL_TREE) > > + { > > + /* We allow an optional second argument in the GNU form of > > + attribute deprecated, which specifies the replacement. */ > > + if (flags & ATTR_FLAG_CXX11) > > + { > > + error ("replacement argument only allowed in GNU attributes"); > > + *no_add_attrs = true; > > + } > > + else if (TREE_CODE (TREE_VALUE (TREE_CHAIN (args))) != STRING_CST) > > + { > > + error ("replacement argument is not a string"); > > + *no_add_attrs = true; > > + } > > + } > > > > if (DECL_P (*node)) > > { > > diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c > > index fa29d2c15fc..2b47f01d166 100644 > > --- a/gcc/c/c-parser.c > > +++ b/gcc/c/c-parser.c > > @@ -4952,6 +4952,14 @@ c_parser_std_attribute (c_parser *parser, bool > > for_tm) > > TREE_VALUE (attribute) > > = c_parser_attribute_arguments (parser, takes_identifier, > > require_string, false); > > + if (c_parser_next_token_is (parser, CPP_COMMA) > > + && strcmp (IDENTIFIER_POINTER (name), "deprecated") == 0) > > + { > > + error_at (open_loc, "replacement argument only allowed in " > > + "GNU attributes"); > > + c_parser_skip_until_found (parser, CPP_CLOSE_PAREN, NULL); > > + return error_mark_node; > > + } > > } > > else > > c_parser_balanced_token_sequence (parser); > > diff --git a/gcc/doc/extend.texi b/gcc/doc/extend.texi > > index 9501a60f20e..7d399f4b2bc 100644 > > --- a/gcc/doc/extend.texi > > +++ b/gcc/doc/extend.texi > > @@ -2860,6 +2860,7 @@ StrongAlias (allocate, alloc); > > > > @item deprecated > > @itemx deprecated (@var{msg}) > > +@itemx deprecated (@var{msg}, @var{replacement}) > > @cindex @code{deprecated} function attribute > > The @code{deprecated} attribute results in a warning if the function > > is used anywhere in the source file. This is useful when identifying > > @@ -2880,6 +2881,13 @@ results in a warning on line 3 but not line 2. The > > optional @var{msg} > > argument, which must be a string, is printed in the warning if > > present. > > > > +This attribute accepts an optional second argument which specifies > > +the replacement that ought to be used instead: > > + > > +@smallexample > > +int old_fn () __attribute__ ((deprecated("unsafe", "new_fn"))); > > +@end smallexample > > + > > The @code{deprecated} attribute can also be used for variables and > > types (@pxref{Variable Attributes}, @pxref{Type Attributes}.) > > > > @@ -7409,6 +7417,7 @@ attribute is also not copied. @xref{Common Function > > Attributes}. > > > > @item deprecated > > @itemx deprecated (@var{msg}) > > +@itemx deprecated (@var{msg}, @var{replacement}) > > @cindex @code{deprecated} variable attribute > > The @code{deprecated} attribute results in a warning if the variable > > is used anywhere in the source file. This is useful when identifying > > @@ -7429,6 +7438,13 @@ results in a warning on line 3 but not line 2. The > > optional @var{msg} > > argument, which must be a string, is printed in the warning if > > present. > > > > +This attribute accepts an optional second argument which specifies > > +the replacement that ought to be used instead: > > + > > +@smallexample > > +extern int old_var __attribute__ ((deprecated("unsafe", "new_var"))); > > +@end smallexample > > + > > The @code{deprecated} attribute can also be used for functions and > > types (@pxref{Common Function Attributes}, > > @pxref{Common Type Attributes}). > > @@ -8492,6 +8508,7 @@ struct __attribute__ ((copy ( (struct A *)0)) B @{ /* > > @r{@dots{}} */ @}; > > > > @item deprecated > > @itemx deprecated (@var{msg}) > > +@itemx deprecated (@var{msg}, @var{replacement}) > > @cindex @code{deprecated} type attribute > > The @code{deprecated} attribute results in a warning if the type > > is used anywhere in the source file. This is useful when identifying > > @@ -8522,6 +8539,13 @@ present. Control characters in the string will be > > replaced with > > escape sequences, and if the @option{-fmessage-length} option is set > > to 0 (its default value) then any newline characters will be ignored. > > > > +This attribute accepts an optional second argument which specifies > > +the replacement that ought to be used instead: > > + > > +@smallexample > > +typedef int oldtype __attribute__ ((deprecated("unsafe", "newtype"))); > > +@end smallexample > > + > > The @code{deprecated} attribute can also be used for functions and > > variables (@pxref{Function Attributes}, @pxref{Variable Attributes}.) > > > > diff --git a/gcc/testsuite/c-c++-common/Wdeprecated-arg-1.c > > b/gcc/testsuite/c-c++-common/Wdeprecated-arg-1.c > > new file mode 100644 > > index 00000000000..b03e0e42ad6 > > --- /dev/null > > +++ b/gcc/testsuite/c-c++-common/Wdeprecated-arg-1.c > > @@ -0,0 +1,21 @@ > > +/* PR c++/102049 */ > > +/* { dg-do compile } */ > > +/* { dg-additional-options "-std=c++11" { target c++ } } */ > > + > > +typedef int __attribute__((deprecated("obsolete", "newtype"))) oldtype; > > +__attribute__((deprecated("unsafe", "get_it_s"))) void get_it (int); /* { > > dg-message "declared here" } */ > > +[[gnu::deprecated("g", "")]] void g(); /* { dg-error "only allowed in GNU > > attributes" } */ > > +[[deprecated("h", "")]] void h(); /* { dg-error "only allowed in GNU > > attributes" } */ > > +__attribute__((deprecated("unsafe", 1))) void f2(); /* { dg-error > > "argument is not a string" } */ > > +__attribute__((deprecated("unsafe", "newvar"))) int oldvar; /* { > > dg-message "declared here" } */ > > + > > +int > > +main () > > +{ > > + get_it (42); /* { dg-warning "is deprecated: unsafe" } */ > > + /* { dg-message "use .get_it_s. instead" "" { target *-*-* } .-1 } */ > > + oldtype t; /* { dg-warning "is deprecated: obsolete" } */ > > + /* { dg-message "use .newtype. instead" "" { target *-*-* } .-1 } */ > > + int i = oldvar; /* { dg-warning "is deprecated: unsafe" } */ > > + /* { dg-message "use .newvar. instead" "" { target *-*-* } .-1 } */ > > +} > > diff --git a/gcc/testsuite/gcc.dg/c2x-attr-deprecated-3.c > > b/gcc/testsuite/gcc.dg/c2x-attr-deprecated-3.c > > index 044725e5123..6cb70705bbf 100644 > > --- a/gcc/testsuite/gcc.dg/c2x-attr-deprecated-3.c > > +++ b/gcc/testsuite/gcc.dg/c2x-attr-deprecated-3.c > > @@ -6,6 +6,6 @@ > > > > [[deprecated(0)]] int b; /* { dg-error "expected" } */ > > > > -[[deprecated("", 123)]] int c; /* { dg-error "expected" } */ > > +[[deprecated("", 123)]] int c; /* { dg-error "only allowed in GNU > > attributes" } */ > > > > [[deprecated((""))]] int d; /* { dg-error "expected" } */ > > diff --git a/gcc/tree.c b/gcc/tree.c > > index 561b9cd56bd..5cb2d57a960 100644 > > --- a/gcc/tree.c > > +++ b/gcc/tree.c > > @@ -12002,8 +12002,9 @@ bool > > warn_deprecated_use (tree node, tree attr) > > { > > escaped_string msg; > > + escaped_string rep; > > > > - if (node == 0 || !warn_deprecated_decl) > > + if (node == NULL_TREE || !warn_deprecated_decl) > > return false; > > > > if (!attr) > > @@ -12023,7 +12024,12 @@ warn_deprecated_use (tree node, tree attr) > > attr = lookup_attribute ("deprecated", attr); > > > > if (attr) > > - msg.escape (TREE_STRING_POINTER (TREE_VALUE (TREE_VALUE (attr)))); > > + { > > + tree val = TREE_VALUE (attr); > > + msg.escape (TREE_STRING_POINTER (TREE_VALUE (val))); > > + if (TREE_CHAIN (val)) > > + rep.escape (TREE_STRING_POINTER (TREE_VALUE (TREE_CHAIN (val)))); > > + } > > > > bool w = false; > > if (DECL_P (node)) > > @@ -12036,7 +12042,11 @@ warn_deprecated_use (tree node, tree attr) > > w = warning (OPT_Wdeprecated_declarations, > > "%qD is deprecated", node); > > if (w) > > - inform (DECL_SOURCE_LOCATION (node), "declared here"); > > + { > > + if (rep) > > + inform (input_location, "use %qs instead", (const char *) rep); > > + inform (DECL_SOURCE_LOCATION (node), "declared here"); > > + } > > } > > else if (TYPE_P (node)) > > { > > @@ -12072,8 +12082,13 @@ warn_deprecated_use (tree node, tree attr) > > "type is deprecated"); > > } > > > > - if (w && decl) > > - inform (DECL_SOURCE_LOCATION (decl), "declared here"); > > + if (w) > > + { > > + if (rep) > > + inform (input_location, "use %qs instead", (const char *) rep); > > + if (decl) > > + inform (DECL_SOURCE_LOCATION (decl), "declared here"); > > + } > > } > > > > return w; > > > > base-commit: f6a05b23cc2e53c38e8321ddb5d2cbe40737e506 > > -- > > 2.31.1 > > > > Marek >