Message ID | YbzTm2OK51VQvqUt@redhat.com |
---|---|
State | New |
Headers | show |
Series | [v3] attribs: Fix wrong error with -Wno-attribute=A::b [PR103649] | expand |
On 12/17/21 13:14, Marek Polacek wrote: > On Thu, Dec 16, 2021 at 08:06:43PM -0500, Jason Merrill wrote: >> On 12/16/21 19:52, Marek Polacek wrote: >>> --- /dev/null >>> +++ b/gcc/testsuite/c-c++-common/Wno-attributes-6.c >>> @@ -0,0 +1,14 @@ >>> +/* PR c/103649 */ >>> +/* { dg-do compile { target { c || c++11 } } } */ >>> +/* { dg-additional-options "-Wno-attributes=foo::bar" } */ >>> +/* { dg-additional-options "-Wno-attributes=baz::" } */ >>> +/* { dg-additional-options "-Wno-attributes=womp::womp" } */ >>> +/* { dg-additional-options "-Wno-attributes=qux::foo" } */ >>> + >>> +[[foo::bar(1, 2)]]; /* { dg-warning "attribute ignored" } */ >>> +[[baz::bar(1, 2)]]; /* { dg-warning "attribute ignored" } */ >>> +[[foo::bar(1, 2)]] void f1(); >>> +[[baz::bar(1, 2)]] void f2(); >>> +[[qux::foo({t})]] void f3(); >>> +[[womp::womp (another::directive (threadprivate (t)))]] void f4(); >>> +[[womp::womp (another::directive (threadprivate (t)))]]; /* { dg-warning "attribute ignored" } */ >> >> If we're ignoring these attributes, we should ignore them everywhere; >> perhaps using them for an attribute-declaration is meaningful in another >> compiler. > > Sounds good. Reminds me of P177, Portable assumptions... > > Bootstrapped/regtested on x86_64-pc-linux-gnu, ok for trunk? > > -- >8 -- > My patch to implement -Wno-attribute=A::b caused a bogus error when > parsing > > [[foo::bar(1, 2)]]; > > when -Wno-attributes=foo::bar was specified on the command line, because > when we create a fake foo::bar attribute and insert it into our attribute > table, it is created with max_length == 0 which doesn't allow any args. > That is wrong -- we know nothing about the attribute, so we shouldn't > require any specific number of arguments. And since unknown attributes > can be rather complex (see for example omp::{directive,sequence}), we > must skip parsing their arguments. To that end, I'm using max_length > with value -2. > > Also let's not warn about things like > > [[vendor::assume(true)]]; > > because they may have some meaning (this is reminiscent of C++ Portable > Assumptions). > > PR c/103649 > > gcc/ChangeLog: > > * attribs.c (handle_ignored_attributes_option): Create the fake > attribute with max_length == -2. > (attribute_ignored_p): New function. > * attribs.h (attribute_ignored_p): Declare. > * tree-core.h (struct attribute_spec): Document that max_length > can be -2. > > gcc/c/ChangeLog: > > * c-decl.c (c_warn_unused_attributes): Don't warn for > attribute_ignored_p. > * c-parser.c (c_parser_std_attribute): Skip parsing of the attribute > arguments when max_length == -2. > > gcc/cp/ChangeLog: > > * parser.c (cp_parser_declaration): Don't warn for attribute_ignored_p. > (cp_parser_std_attribute): Skip parsing of the attribute > arguments when max_length == -2. > > gcc/testsuite/ChangeLog: > > * c-c++-common/Wno-attributes-6.c: New test. > --- > gcc/attribs.c | 20 ++++++++++++++++++- > gcc/attribs.h | 1 + > gcc/c/c-decl.c | 2 +- > gcc/c/c-parser.c | 4 +++- > gcc/cp/parser.c | 6 ++++-- > gcc/testsuite/c-c++-common/Wno-attributes-6.c | 16 +++++++++++++++ > gcc/tree-core.h | 4 +++- > 7 files changed, 47 insertions(+), 6 deletions(-) > create mode 100644 gcc/testsuite/c-c++-common/Wno-attributes-6.c > > diff --git a/gcc/attribs.c b/gcc/attribs.c > index 29703e75fba..82527869093 100644 > --- a/gcc/attribs.c > +++ b/gcc/attribs.c > @@ -304,7 +304,7 @@ handle_ignored_attributes_option (vec<char *> *v) > We can't free it here, so squirrel away the pointers. */ > attribute_spec *table = new attribute_spec[2]; > ignored_attributes_table.safe_push (table); > - table[0] = { attr, 0, 0, false, false, false, false, nullptr, nullptr }; > + table[0] = { attr, 0, -2, false, false, false, false, nullptr, nullptr }; > table[1] = { nullptr, 0, 0, false, false, false, false, nullptr, > nullptr }; > register_scoped_attributes (table, IDENTIFIER_POINTER (vendor_id), !attr); > @@ -569,6 +569,24 @@ attr_namespace_ignored_p (tree ns) > return r && r->ignored_p; > } > > +/* Return true if the attribute ATTR should not be warned about. */ > + > +bool > +attribute_ignored_p (tree attr) > +{ > + if (!cxx11_attribute_p (attr)) > + return false; > + if (tree ns = get_attribute_namespace (attr)) > + { > + if (attr_namespace_ignored_p (ns)) > + return true; > + const attribute_spec *as = lookup_attribute_spec (TREE_PURPOSE (attr)); > + if (as && as->max_length == -2) > + return true; > + } > + return false; > +} > + > /* Process the attributes listed in ATTRIBUTES and install them in *NODE, > which is either a DECL (including a TYPE_DECL) or a TYPE. If a DECL, > it should be modified in place; if a TYPE, a copy should be created > diff --git a/gcc/attribs.h b/gcc/attribs.h > index f5899d83c0b..d3449d5bd1d 100644 > --- a/gcc/attribs.h > +++ b/gcc/attribs.h > @@ -39,6 +39,7 @@ extern tree get_attribute_name (const_tree); > extern tree get_attribute_namespace (const_tree); > extern void apply_tm_attr (tree, tree); > extern tree make_attribute (const char *, const char *, tree); > +extern bool attribute_ignored_p (tree); > > extern struct scoped_attributes* register_scoped_attributes (const struct attribute_spec *, > const char *, > diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c > index 4b5481ce8f4..516e3c26e21 100644 > --- a/gcc/c/c-decl.c > +++ b/gcc/c/c-decl.c > @@ -4643,7 +4643,7 @@ c_warn_unused_attributes (tree attrs) > constraint violation. */ > pedwarn (input_location, OPT_Wattributes, "%qE attribute ignored", > get_attribute_name (t)); > - else > + else if (!attribute_ignored_p (t)) > warning (OPT_Wattributes, "%qE attribute ignored", > get_attribute_name (t)); > } > diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c > index d7e5f051ac0..c9068bdbb8a 100644 > --- a/gcc/c/c-parser.c > +++ b/gcc/c/c-parser.c > @@ -4943,7 +4943,9 @@ c_parser_std_attribute (c_parser *parser, bool for_tm) > parens.skip_until_found_close (parser); > return error_mark_node; > } > - if (as) > + /* When MAX_LENGTH is -2, this is a fake attribute created to > + handle -Wno-attributes, and we must skip parsing the arguments. */ > + if (as && as->max_length != -2) > { > bool takes_identifier > = (ns != NULL_TREE > diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c > index 44eed7ea638..a843c953da8 100644 > --- a/gcc/cp/parser.c > +++ b/gcc/cp/parser.c > @@ -14776,7 +14776,7 @@ cp_parser_declaration (cp_parser* parser, tree prefix_attrs) > } > } > > - if (std_attrs != NULL_TREE) > + if (std_attrs != NULL_TREE && !attribute_ignored_p (std_attrs)) > warning_at (make_location (attrs_loc, attrs_loc, parser->lexer), > OPT_Wattributes, "attribute ignored"); > if (cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON)) > @@ -28979,7 +28979,9 @@ cp_parser_std_attribute (cp_parser *parser, tree attr_ns) > /* A GNU attribute that takes an identifier in parameter. */ > attr_flag = id_attr; > > - if (as == NULL) > + /* When MAX_LENGTH is -2, this is a fake attribute created to > + handle -Wno-attributes, and we must skip parsing the arguments. */ > + if (as == NULL || as->max_length == -2) Rather than require multiple places to know about the magic -2, could we have an overload of attribute_ignored_p that takes an attribute_spec*? OK with that change. > { > if ((flag_openmp || flag_openmp_simd) && attr_ns == omp_identifier) > { > diff --git a/gcc/testsuite/c-c++-common/Wno-attributes-6.c b/gcc/testsuite/c-c++-common/Wno-attributes-6.c > new file mode 100644 > index 00000000000..ca3c7bebb99 > --- /dev/null > +++ b/gcc/testsuite/c-c++-common/Wno-attributes-6.c > @@ -0,0 +1,16 @@ > +/* PR c/103649 */ > +/* { dg-do compile { target { c || c++11 } } } */ > +/* { dg-additional-options "-Wno-attributes=foo::bar" } */ > +/* { dg-additional-options "-Wno-attributes=baz::" } */ > +/* { dg-additional-options "-Wno-attributes=womp::womp" } */ > +/* { dg-additional-options "-Wno-attributes=qux::foo" } */ > +/* { dg-additional-options "-Wno-attributes=vendor::assume" } */ > + > +[[vendor::assume(1 + 1 == 2)]]; > +[[foo::bar(1, 2)]]; > +[[baz::bar(1, 2)]]; > +[[foo::bar(1, 2)]] void f1(); > +[[baz::bar(1, 2)]] void f2(); > +[[qux::foo({t})]] void f3(); > +[[womp::womp (another::directive (threadprivate (t)))]] void f4(); > +[[womp::womp (another::directive (threadprivate (t)))]]; > diff --git a/gcc/tree-core.h b/gcc/tree-core.h > index 91ae5237d7e..9b37a065d18 100644 > --- a/gcc/tree-core.h > +++ b/gcc/tree-core.h > @@ -2077,7 +2077,9 @@ struct attribute_spec { > /* The minimum length of the list of arguments of the attribute. */ > int min_length; > /* The maximum length of the list of arguments of the attribute > - (-1 for no maximum). */ > + (-1 for no maximum). It can also be -2 for fake attributes > + created for the sake of -Wno-attributes; in that case, we > + should skip the balanced token sequence when parsing the attribute. */ > int max_length; > /* Whether this attribute requires a DECL. If it does, it will be passed > from types of DECLs, function return types and array element types to > > base-commit: d7ca2a79b82c6500ead6ab983d14c609e2124eee
diff --git a/gcc/attribs.c b/gcc/attribs.c index 29703e75fba..82527869093 100644 --- a/gcc/attribs.c +++ b/gcc/attribs.c @@ -304,7 +304,7 @@ handle_ignored_attributes_option (vec<char *> *v) We can't free it here, so squirrel away the pointers. */ attribute_spec *table = new attribute_spec[2]; ignored_attributes_table.safe_push (table); - table[0] = { attr, 0, 0, false, false, false, false, nullptr, nullptr }; + table[0] = { attr, 0, -2, false, false, false, false, nullptr, nullptr }; table[1] = { nullptr, 0, 0, false, false, false, false, nullptr, nullptr }; register_scoped_attributes (table, IDENTIFIER_POINTER (vendor_id), !attr); @@ -569,6 +569,24 @@ attr_namespace_ignored_p (tree ns) return r && r->ignored_p; } +/* Return true if the attribute ATTR should not be warned about. */ + +bool +attribute_ignored_p (tree attr) +{ + if (!cxx11_attribute_p (attr)) + return false; + if (tree ns = get_attribute_namespace (attr)) + { + if (attr_namespace_ignored_p (ns)) + return true; + const attribute_spec *as = lookup_attribute_spec (TREE_PURPOSE (attr)); + if (as && as->max_length == -2) + return true; + } + return false; +} + /* Process the attributes listed in ATTRIBUTES and install them in *NODE, which is either a DECL (including a TYPE_DECL) or a TYPE. If a DECL, it should be modified in place; if a TYPE, a copy should be created diff --git a/gcc/attribs.h b/gcc/attribs.h index f5899d83c0b..d3449d5bd1d 100644 --- a/gcc/attribs.h +++ b/gcc/attribs.h @@ -39,6 +39,7 @@ extern tree get_attribute_name (const_tree); extern tree get_attribute_namespace (const_tree); extern void apply_tm_attr (tree, tree); extern tree make_attribute (const char *, const char *, tree); +extern bool attribute_ignored_p (tree); extern struct scoped_attributes* register_scoped_attributes (const struct attribute_spec *, const char *, diff --git a/gcc/c/c-decl.c b/gcc/c/c-decl.c index 4b5481ce8f4..516e3c26e21 100644 --- a/gcc/c/c-decl.c +++ b/gcc/c/c-decl.c @@ -4643,7 +4643,7 @@ c_warn_unused_attributes (tree attrs) constraint violation. */ pedwarn (input_location, OPT_Wattributes, "%qE attribute ignored", get_attribute_name (t)); - else + else if (!attribute_ignored_p (t)) warning (OPT_Wattributes, "%qE attribute ignored", get_attribute_name (t)); } diff --git a/gcc/c/c-parser.c b/gcc/c/c-parser.c index d7e5f051ac0..c9068bdbb8a 100644 --- a/gcc/c/c-parser.c +++ b/gcc/c/c-parser.c @@ -4943,7 +4943,9 @@ c_parser_std_attribute (c_parser *parser, bool for_tm) parens.skip_until_found_close (parser); return error_mark_node; } - if (as) + /* When MAX_LENGTH is -2, this is a fake attribute created to + handle -Wno-attributes, and we must skip parsing the arguments. */ + if (as && as->max_length != -2) { bool takes_identifier = (ns != NULL_TREE diff --git a/gcc/cp/parser.c b/gcc/cp/parser.c index 44eed7ea638..a843c953da8 100644 --- a/gcc/cp/parser.c +++ b/gcc/cp/parser.c @@ -14776,7 +14776,7 @@ cp_parser_declaration (cp_parser* parser, tree prefix_attrs) } } - if (std_attrs != NULL_TREE) + if (std_attrs != NULL_TREE && !attribute_ignored_p (std_attrs)) warning_at (make_location (attrs_loc, attrs_loc, parser->lexer), OPT_Wattributes, "attribute ignored"); if (cp_lexer_next_token_is (parser->lexer, CPP_SEMICOLON)) @@ -28979,7 +28979,9 @@ cp_parser_std_attribute (cp_parser *parser, tree attr_ns) /* A GNU attribute that takes an identifier in parameter. */ attr_flag = id_attr; - if (as == NULL) + /* When MAX_LENGTH is -2, this is a fake attribute created to + handle -Wno-attributes, and we must skip parsing the arguments. */ + if (as == NULL || as->max_length == -2) { if ((flag_openmp || flag_openmp_simd) && attr_ns == omp_identifier) { diff --git a/gcc/testsuite/c-c++-common/Wno-attributes-6.c b/gcc/testsuite/c-c++-common/Wno-attributes-6.c new file mode 100644 index 00000000000..ca3c7bebb99 --- /dev/null +++ b/gcc/testsuite/c-c++-common/Wno-attributes-6.c @@ -0,0 +1,16 @@ +/* PR c/103649 */ +/* { dg-do compile { target { c || c++11 } } } */ +/* { dg-additional-options "-Wno-attributes=foo::bar" } */ +/* { dg-additional-options "-Wno-attributes=baz::" } */ +/* { dg-additional-options "-Wno-attributes=womp::womp" } */ +/* { dg-additional-options "-Wno-attributes=qux::foo" } */ +/* { dg-additional-options "-Wno-attributes=vendor::assume" } */ + +[[vendor::assume(1 + 1 == 2)]]; +[[foo::bar(1, 2)]]; +[[baz::bar(1, 2)]]; +[[foo::bar(1, 2)]] void f1(); +[[baz::bar(1, 2)]] void f2(); +[[qux::foo({t})]] void f3(); +[[womp::womp (another::directive (threadprivate (t)))]] void f4(); +[[womp::womp (another::directive (threadprivate (t)))]]; diff --git a/gcc/tree-core.h b/gcc/tree-core.h index 91ae5237d7e..9b37a065d18 100644 --- a/gcc/tree-core.h +++ b/gcc/tree-core.h @@ -2077,7 +2077,9 @@ struct attribute_spec { /* The minimum length of the list of arguments of the attribute. */ int min_length; /* The maximum length of the list of arguments of the attribute - (-1 for no maximum). */ + (-1 for no maximum). It can also be -2 for fake attributes + created for the sake of -Wno-attributes; in that case, we + should skip the balanced token sequence when parsing the attribute. */ int max_length; /* Whether this attribute requires a DECL. If it does, it will be passed from types of DECLs, function return types and array element types to