fixup! [clang] Ignore GCC 11 [[malloc(x)]] attribute

Move diag::warn_multiarg_malloc_attribute_ignored to
`DiagnosticSemaKinds.td` and make it generic so we can use it for other
attributes.

Fixes #68059 (comment)

Author: aloisklink

clang/include/clang/Basic/DiagnosticCommonKinds.td

@@ -177,10 +177,6 @@ def warn_unknown_attribute_ignored : Warning<
   "unknown attribute %0 ignored">, InGroup<UnknownAttributes>;
 def warn_attribute_ignored : Warning<"%0 attribute ignored">,
   InGroup<IgnoredAttributes>;
-def warn_multiarg_malloc_attribute_ignored: Warning<
-  "'malloc' attribute ignored because"
-  " Clang does not support the one/two argument form">,
-  InGroup<IgnoredAttributes>;
 def err_keyword_not_supported_on_target : Error<
   "%0 is not supported on this target">;
 def err_use_of_tag_name_without_tag : Error<

clang/include/clang/Basic/DiagnosticSemaKinds.td

@@ -3028,6 +3028,10 @@ def warn_auto_var_is_id : Warning<
   InGroup<DiagGroup<"auto-var-id">>;
 
 // Attributes
+def warn_attribute_form_ignored : Warning<
+  "%0 attribute ignored because Clang does not yet support this attribute signature">,
+  InGroup<IgnoredAttributes>;
+
 def warn_attribute_ignored_no_calls_in_stmt: Warning<
   "%0 attribute is ignored because there exists no call expression inside the "
   "statement">,

clang/lib/Sema/SemaDeclAttr.cpp

@@ -2084,7 +2084,7 @@ static void handleRestrictAttr(Sema &S, Decl *D, const ParsedAttr &AL) {
   // FIXME: GCC uses [[malloc(my_func)]] to specify a deallocator for the
   // returned pointer, but this isn't currently supported in LLVM
   // see https://github.com/llvm/llvm-project/issues/51607
-  S.Diag(AL.getLoc(), diag::warn_multiarg_malloc_attribute_ignored);
+  S.Diag(AL.getLoc(), diag::warn_attribute_form_ignored) << AL;
 }
 
 static void handleCPUSpecificAttr(Sema &S, Decl *D, const ParsedAttr &AL) {

clang/test/Sema/attr-args.c

@@ -8,7 +8,7 @@ inline __attribute__((const(a))) void *f4(void);  // expected-error {{'const' at
 inline __attribute__((fastcall(a))) void *f5(void);  // expected-error {{'fastcall' attribute takes no arguments}}
 inline __declspec(restrict(a)) void *f6_a(void);  // expected-error {{'restrict' attribute takes no arguments}}
 inline __attribute__((malloc(a, 1, a))) void *f6_b(void);  // expected-error {{'malloc' attribute takes no more than 2 arguments}}
-inline __attribute__((malloc(a, 1))) void *f6_c(void);  // expected-warning {{'malloc' attribute ignored because Clang does not support the one/two argument form}}
+inline __attribute__((malloc(a, 1))) void *f6_c(void);  // expected-warning {{'malloc' attribute ignored because Clang does not yet support this attribute signature}}
 inline __attribute__((nothrow(a))) void *f7(void);  // expected-error {{'nothrow' attribute takes no arguments}}
 inline __attribute__((stdcall(a))) void *f8(void);  // expected-error {{'stdcall' attribute takes no arguments}}
 inline __attribute__((used(a))) void *f9(void);  // expected-error {{'used' attribute takes no arguments}}