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[130.44.159.43]) by smtp.gmail.com with ESMTPSA id c20-20020ac86614000000b003447c4f5aa5sm245252qtp.24.2022.10.06.11.34.25 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 06 Oct 2022 11:34:26 -0700 (PDT) Message-ID: Date: Thu, 6 Oct 2022 14:34:24 -0400 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.13.1 Subject: Re: [PATCH] c++, v3: Improve handling of foreigner namespace attributes To: Jakub Jelinek Cc: gcc-patches@gcc.gnu.org References: <1a197a3f-f022-5293-323b-c53a9d43e946@redhat.com> <2ac0433b-e615-35e6-f2a6-197b156ca2e2@redhat.com> From: Jason Merrill In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Spam-Status: No, score=-7.3 required=5.0 tests=BAYES_00,DKIMWL_WL_HIGH,DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,NICE_REPLY_A,RCVD_IN_DNSWL_NONE,SPF_HELO_NONE,SPF_NONE,TXREP autolearn=ham autolearn_force=no version=3.4.6 X-Spam-Checker-Version: SpamAssassin 3.4.6 (2021-04-09) on server2.sourceware.org List-Id: On 10/6/22 14:29, Jakub Jelinek wrote: > On Thu, Oct 06, 2022 at 01:30:18PM -0400, Jason Merrill wrote: >> Yes, except I was thinking the new function would take the attribute >> TREE_LIST as its parameter so that all the callers don't have to also call >> get_attribute_namespace. > > Ok, here it is in patch form. > > 2022-10-06 Jakub Jelinek > > gcc/ > * attribs.h (is_attribute_namespace_p): New inline function. > (lookup_attribute): Document meaning of ATTR_NS equal to "". > * attribs.cc (remove_attribute): Use is_attribute_namespace_p. > (private_lookup_attribute): For ATTR_NS "" match either standard > attribute or "gnu" namespace one. > gcc/c-family/ > * c-common.cc (attribute_fallthrough_p): Lookup fallthrough attribute > only in gnu namespace or as standard attribute, treat fallthrough > attributes in other namespaces like any other unknown attribute. > gcc/cp/ > * parser.cc (cp_parser_check_std_attribute): Only do checks if > attribute is a standard attribute or in gnu namespace and only > lookup other attributes in those namespaces. > * cp-gimplify.cc (lookup_hotness_attribute): Adjust function comment. > Only return true for standard attribute or gnu namespace attribute. > (remove_hotness_attribute): Only remove hotness attributes when > they are standard or in gnu namespace, implement it in a single > loop rather than former 4 now 8 remove_attribute calls. > gcc/testsuite/ > * g++.dg/cpp1z/fallthrough2.C: New test. > * g++.dg/cpp2a/attr-likely7.C: New test. > > --- gcc/attribs.h.jj 2022-10-05 16:15:29.834889059 +0200 > +++ gcc/attribs.h 2022-10-06 20:22:37.946494304 +0200 > @@ -188,6 +188,22 @@ is_attribute_p (const char *attr_name, c > IDENTIFIER_POINTER (ident), IDENTIFIER_LENGTH (ident)); > } > > +/* Given an attribute name ATTR and a string ATTR_NS, return true The word "name" here is wrong now. OK with that fixed, thanks. > + if the identifier node is a valid attribute namespace for the string. > + ATTR_NS "" stands for standard attribute (NULL IDENT) or "gnu" > + namespace. */ > + > +static inline bool > +is_attribute_namespace_p (const char *attr_ns, const_tree attr) > +{ > + tree ident = get_attribute_namespace (attr); > + if (attr_ns == NULL) > + return ident == NULL_TREE; > + if (attr_ns[0]) > + return ident && is_attribute_p (attr_ns, ident); > + return ident == NULL_TREE || is_attribute_p ("gnu", ident); > +} > + > /* Given an attribute name ATTR_NAME and a list of attributes LIST, > return a pointer to the attribute's list element if the attribute > is part of the list, or NULL_TREE if not found. If the attribute > @@ -217,7 +233,8 @@ lookup_attribute (const char *attr_name, > } > } > > -/* Similar to lookup_attribute, but also match the attribute namespace. */ > +/* Similar to lookup_attribute, but also match the attribute namespace. > + ATTR_NS "" stands for either standard attribute or "gnu" namespace. */ > > static inline tree > lookup_attribute (const char *attr_ns, const char *attr_name, tree list) > --- gcc/attribs.cc.jj 2022-10-04 23:13:10.289090796 +0200 > +++ gcc/attribs.cc 2022-10-06 20:23:35.693713861 +0200 > @@ -1645,7 +1645,8 @@ remove_attribute (const char *attr_name, > return list; > } > > -/* Similarly but also match namespace on the removed attributes. */ > +/* Similarly but also match namespace on the removed attributes. > + ATTR_NS "" stands for NULL or "gnu" namespace. */ > > tree > remove_attribute (const char *attr_ns, const char *attr_name, tree list) > @@ -1659,15 +1660,11 @@ remove_attribute (const char *attr_ns, c > tree l = *p; > > tree attr = get_attribute_name (l); > - if (is_attribute_p (attr_name, attr)) > + if (is_attribute_p (attr_name, attr) > + && is_attribute_namespace_p (attr_ns, l)) > { > - tree ns = get_attribute_namespace (l); > - if ((ns == NULL_TREE && attr_ns == NULL) > - || (ns && attr_ns && is_attribute_p (attr_ns, ns))) > - { > - *p = TREE_CHAIN (l); > - continue; > - } > + *p = TREE_CHAIN (l); > + continue; > } > p = &TREE_CHAIN (l); > } > @@ -2088,14 +2085,20 @@ private_lookup_attribute (const char *at > tree ns = get_attribute_namespace (list); > if (ns == NULL_TREE) > { > - if (attr_ns == NULL) > + if (attr_ns_len == 0) > break; > } > else if (attr_ns) > { > ident_len = IDENTIFIER_LENGTH (ns); > - if (cmp_attribs (attr_ns, attr_ns_len, IDENTIFIER_POINTER (ns), > - ident_len)) > + if (attr_ns_len == 0) > + { > + if (cmp_attribs ("gnu", strlen ("gnu"), > + IDENTIFIER_POINTER (ns), ident_len)) > + break; > + } > + else if (cmp_attribs (attr_ns, attr_ns_len, > + IDENTIFIER_POINTER (ns), ident_len)) > break; > } > } > --- gcc/c-family/c-common.cc.jj 2022-10-06 17:43:47.880502941 +0200 > +++ gcc/c-family/c-common.cc 2022-10-06 20:24:17.220152623 +0200 > @@ -6008,12 +6008,12 @@ attribute_fallthrough_p (tree attr) > { > if (attr == error_mark_node) > return false; > - tree t = lookup_attribute ("fallthrough", attr); > + tree t = lookup_attribute ("", "fallthrough", attr); > if (t == NULL_TREE) > return false; > /* It is no longer true that "this attribute shall appear at most once in > each attribute-list", but we still give a warning. */ > - if (lookup_attribute ("fallthrough", TREE_CHAIN (t))) > + if (lookup_attribute ("", "fallthrough", TREE_CHAIN (t))) > warning (OPT_Wattributes, "attribute % specified multiple " > "times"); > /* No attribute-argument-clause shall be present. */ > @@ -6024,7 +6024,8 @@ attribute_fallthrough_p (tree attr) > for (t = attr; t != NULL_TREE; t = TREE_CHAIN (t)) > { > tree name = get_attribute_name (t); > - if (!is_attribute_p ("fallthrough", name)) > + if (!is_attribute_p ("fallthrough", name) > + || !is_attribute_namespace_p ("", t)) > { > if (!c_dialect_cxx () && get_attribute_namespace (t) == NULL_TREE) > /* The specifications of standard attributes in C mean > --- gcc/cp/parser.cc.jj 2022-10-06 17:43:42.418576616 +0200 > +++ gcc/cp/parser.cc 2022-10-06 20:25:01.004560878 +0200 > @@ -29265,7 +29265,8 @@ cp_parser_check_std_attribute (location_ > if (attributes) > for (const auto &a : alist) > if (is_attribute_p (a, get_attribute_name (attribute)) > - && lookup_attribute (a, attributes)) > + && is_attribute_namespace_p ("", attribute) > + && lookup_attribute ("", a, attributes)) > { > if (!from_macro_expansion_at (loc)) > warning_at (loc, OPT_Wattributes, "attribute %qs specified " > --- gcc/cp/cp-gimplify.cc.jj 2022-10-06 17:43:42.413576684 +0200 > +++ gcc/cp/cp-gimplify.cc 2022-10-06 20:24:43.145802239 +0200 > @@ -3027,7 +3027,7 @@ cp_fold (tree x) > return x; > } > > -/* Look up either "hot" or "cold" in attribute list LIST. */ > +/* Look up "hot", "cold", "likely" or "unlikely" in attribute list LIST. */ > > tree > lookup_hotness_attribute (tree list) > @@ -3035,24 +3035,36 @@ lookup_hotness_attribute (tree list) > for (; list; list = TREE_CHAIN (list)) > { > tree name = get_attribute_name (list); > - if (is_attribute_p ("hot", name) > - || is_attribute_p ("cold", name) > - || is_attribute_p ("likely", name) > - || is_attribute_p ("unlikely", name)) > + if ((is_attribute_p ("hot", name) > + || is_attribute_p ("cold", name) > + || is_attribute_p ("likely", name) > + || is_attribute_p ("unlikely", name)) > + && is_attribute_namespace_p ("", list)) > break; > } > return list; > } > > -/* Remove both "hot" and "cold" attributes from LIST. */ > +/* Remove "hot", "cold", "likely" and "unlikely" attributes from LIST. */ > > static tree > remove_hotness_attribute (tree list) > { > - list = remove_attribute ("hot", list); > - list = remove_attribute ("cold", list); > - list = remove_attribute ("likely", list); > - list = remove_attribute ("unlikely", list); > + for (tree *p = &list; *p; ) > + { > + tree l = *p; > + tree name = get_attribute_name (l); > + if ((is_attribute_p ("hot", name) > + || is_attribute_p ("cold", name) > + || is_attribute_p ("likely", name) > + || is_attribute_p ("unlikely", name)) > + && is_attribute_namespace_p ("", l)) > + { > + *p = TREE_CHAIN (l); > + continue; > + } > + p = &TREE_CHAIN (l); > + } > return list; > } > > --- gcc/testsuite/g++.dg/cpp1z/fallthrough2.C.jj 2022-10-06 17:45:55.452782142 +0200 > +++ gcc/testsuite/g++.dg/cpp1z/fallthrough2.C 2022-10-06 17:45:55.452782142 +0200 > @@ -0,0 +1,24 @@ > +// { dg-do compile { target c++17 } } > +// { dg-options "-Wextra -Wall -Wpedantic" } > + > +int > +foo (int i) > +{ > + switch (i) > + { > + case 2: > + ++i; > + [[fallthrough, whatever::fallthrough]]; // { dg-bogus "attribute 'fallthrough' specified multiple times" } > + case 3: // { dg-warning "'fallthrough' attribute ignored" "" { target *-*-* } .-1 } > + ++i; > + [[fallthrough, whatever2::fallthrough(1, 2, 3)]]; // { dg-bogus "attribute 'fallthrough' specified multiple times" } > + case 4: // { dg-warning "'fallthrough' attribute ignored" "" { target *-*-* } .-1 } > + [[whatever3::fallthrough("abcd")]]; // { dg-warning "attributes at the beginning of statement are ignored" } > + case 5: > + [[whatever4::fallthrough]]; // { dg-bogus "attribute 'fallthrough' not preceding a case label or default label" } > + ++i; // { dg-warning "attributes at the beginning of statement are ignored" "" { target *-*-* } .-1 } > + default: > + break; > + } > + return i; > +} > --- gcc/testsuite/g++.dg/cpp2a/attr-likely7.C.jj 2022-10-06 17:45:55.452782142 +0200 > +++ gcc/testsuite/g++.dg/cpp2a/attr-likely7.C 2022-10-06 17:45:55.452782142 +0200 > @@ -0,0 +1,38 @@ > +// { dg-do compile { target c++20 } } > +// { dg-additional-options -fdump-tree-gimple } > +// { dg-final { scan-tree-dump-times "hot label" 5 "gimple" } } > +// { dg-final { scan-tree-dump-times "cold label" 3 "gimple" } } > + > +bool b; > + > +template int f() > +{ > + if (b) > + [[likely, whatever::unlikely ("abcd")]] return 0; // { dg-bogus "ignoring attribute 'unlikely' after earlier 'likely'" } > + else // { dg-warning "attributes at the beginning of statement are ignored" "" { target *-*-* } .-1 } > + [[unlikely, whatever2::hot]] flabel: return 1; // { dg-warning "'whatever2::hot' scoped attribute directive ignored" } > + switch (b) > + { > + [[likely, whatever3::cold (1, 2, 3)]] case true: break; // { dg-warning "'whatever3::cold' scoped attribute directive ignored" } > + }; > + return 1; > +} > + > +int main() > +{ > + if (b) > + [[whatever4::unlikely (1), likely]] return 0; // { dg-bogus "ignoring attribute 'likely' after earlier 'unlikely'" } > + else if (b) // { dg-warning "attributes at the beginning of statement are ignored" "" { target *-*-* } .-1 } > + [[whatever5::hot, unlikely]] elabel: // { dg-warning "'whatever5::hot' scoped attribute directive ignored" } > + return 1; > + else > + [[whatever6::cold, likely]] b = false; // { dg-bogus "ignoring attribute 'likely' after earlier 'cold'" } > + // { dg-warning "attributes at the beginning of statement are ignored" "" { target *-*-* } .-1 } > + f(); > + > + switch (b) > + { > + [[whatever7::unlikely (1), likely]] case true: break; // { dg-warning "'whatever7::unlikely' scoped attribute directive ignored" } > + [[whatever8::unlikely, unlikely]] case false: break; // { dg-bogus "attribute 'unlikely' specified multiple times" } > + }; // { dg-warning "'whatever8::unlikely' scoped attribute directive ignored" "" { target *-*-* } .-1 } > +} > > > Jakub >