add extension warning and tests

Author: cor3ntin

clang/include/clang/Basic/DiagnosticParseKinds.td

@@ -1057,6 +1057,15 @@ def ext_ms_abstract_keyword : ExtWarn<
   "'abstract' keyword is a Microsoft extension">,
   InGroup<MicrosoftAbstract>;
 
+def ext_relocatable_keyword : ExtWarn<
+  "'%select{trivially_relocatable|replaceable}0_if_eligible' "
+  "keyword is a C++2c extension">,
+  InGroup<CXX26>;
+def warn_relocatable_keyword  : Warning<
+  "'%select{trivially_relocatable|replaceable}0_if_eligible' "
+  "keyword is incompatible with standards before C++2c">,
+  DefaultIgnore, InGroup<CXXPre26Compat>;
+
 def err_access_specifier_interface : Error<
   "interface types cannot specify '%select{private|protected}0' access">;
 

clang/lib/Parse/ParseDeclCXX.cpp

@@ -2711,6 +2711,12 @@ void Parser::ParseOptionalCXX2CTriviallyRelocatableSpecifier(
     TriviallyRelocatableSpecifier &TRS) {
   assert(isCXX2CTriviallyRelocatableKeyword() &&
          "expected a trivially_relocatable specifier");
+
+  Diag(Tok.getLocation(), getLangOpts().CPlusPlus26
+                              ? diag::warn_relocatable_keyword
+                              : diag::ext_relocatable_keyword)
+      << /*relocatable*/ 0;
+
   TRS = Actions.ActOnTriviallyRelocatableSpecifier(ConsumeToken());
 }
 
@@ -2731,6 +2737,12 @@ bool Parser::isCXX2CReplaceableKeyword() const {
 void Parser::ParseOptionalCXX2CReplaceableSpecifier(ReplaceableSpecifier &MRS) {
   assert(isCXX2CReplaceableKeyword() &&
          "expected a replaceable_if_eligible specifier");
+
+  Diag(Tok.getLocation(), getLangOpts().CPlusPlus26
+                              ? diag::warn_relocatable_keyword
+                              : diag::ext_relocatable_keyword)
+      << /*replaceable*/ 1;
+
   MRS = Actions.ActOnReplaceableSpecifier(ConsumeToken());
 }
 

clang/test/Parser/cxx2c-trivially-relocatable.cpp

@@ -1,8 +1,34 @@
-// RUN: %clang_cc1 -std=c++2b -verify -fsyntax-only %s
+// RUN: %clang_cc1 -std=c++2c -verify=expected -fsyntax-only %s
+// RUN: %clang_cc1 -std=c++11 -verify=expected,cxx11 -fsyntax-only %s
+
 
 
 class A trivially_relocatable_if_eligible {};
+// cxx11-warning@-1 {{'trivially_relocatable_if_eligible' keyword is a C++2c extension}}
 class E final trivially_relocatable_if_eligible {};
+// cxx11-warning@-1 {{'trivially_relocatable_if_eligible' keyword is a C++2c extension}}
 class G trivially_relocatable_if_eligible final{};
+// cxx11-warning@-1 {{'trivially_relocatable_if_eligible' keyword is a C++2c extension}}
 class I trivially_relocatable_if_eligible trivially_relocatable_if_eligible final {}; // expected-error {{class already marked 'trivially_relocatable_if_eligible'}}
+// cxx11-warning@-1 {{'trivially_relocatable_if_eligible' keyword is a C++2c extension}}
 class trivially_relocatable_if_eligible trivially_relocatable_if_eligible {};
+// cxx11-warning@-1 {{'trivially_relocatable_if_eligible' keyword is a C++2c extension}}
+
+class J replaceable_if_eligible{};
+// cxx11-warning@-1 {{'replaceable_if_eligible' keyword is a C++2c extension}}
+class K replaceable_if_eligible replaceable_if_eligible {}; // expected-error {{class already marked 'replaceable_if_eligible'}}
+// cxx11-warning@-1 {{'replaceable_if_eligible' keyword is a C++2c extension}}
+class replaceable_if_eligible replaceable_if_eligible {};
+// cxx11-warning@-1 {{'replaceable_if_eligible' keyword is a C++2c extension}}
+class L replaceable_if_eligible trivially_relocatable_if_eligible final {};
+// cxx11-warning@-1 {{'replaceable_if_eligible' keyword is a C++2c extension}}
+// cxx11-warning@-2 {{'trivially_relocatable_if_eligible' keyword is a C++2c extension}}
+class M replaceable_if_eligible final trivially_relocatable_if_eligible {};
+// cxx11-warning@-1 {{'trivially_relocatable_if_eligible' keyword is a C++2c extension}}
+// cxx11-warning@-2 {{'replaceable_if_eligible' keyword is a C++2c extension}}
+class N final trivially_relocatable_if_eligible replaceable_if_eligible {};
+// cxx11-warning@-1 {{'trivially_relocatable_if_eligible' keyword is a C++2c extension}}
+// cxx11-warning@-2 {{'replaceable_if_eligible' keyword is a C++2c extension}}
+class O trivially_relocatable_if_eligible replaceable_if_eligible final {};
+// cxx11-warning@-1 {{'trivially_relocatable_if_eligible' keyword is a C++2c extension}}
+// cxx11-warning@-2 {{'replaceable_if_eligible' keyword is a C++2c extension}}

clang/www/cxx_status.html

@@ -280,7 +280,7 @@ <h2 id="cxx26">C++2c implementation status</h2>
  <tr>
   <td>Trivial Relocatability</pre></td>
   <td><a href="https://wg21.link/P2786">P2786R13</a></td>
-  <td class="none" align="center">No</td>
+  <td class="unreleased" align="center">Clang 21</td>
  </tr>
  <tr>
   <td><pre>#embed</pre></td>