Add a flag to disable "duplicate definition of category" warnings

[ahatanak]

Fix clang/test/Misc/warning-flags.c

[vsapsai]

As long as there are no other failing tests, looks good to me.

clang/include/clang/Basic/DiagnosticCommonKinds.td

 
 def warn_slh_does_not_support_asm_goto : Warning<
   "speculative load hardening does not protect functions with asm goto">,
   InGroup<DiagGroup<"slh-asm-goto">>;
 }
 
 // Sema && Serialization
 def warn_dup_category_def : Warning<
-  "duplicate definition of category %1 on interface %0">;
+  "duplicate definition of category %1 on interface %0">,
+  InGroup<DiagGroup<"objc-duplicate-category-definition">>;
 
 // Targets
 
 def err_target_unknown_triple : Error<
   "unknown target triple '%0'">;
 def err_target_unknown_cpu : Error<"unknown target CPU '%0'">;
 def note_valid_options : Note<"valid target CPU values are: %0">;
 def err_target_unsupported_cpu_for_micromips : Error<

clang/test/Misc/warning-flags.c

(2) It prevents us adding new warnings to Clang that have no -W flag.  All
     new warnings should have -W flags.
 
     If you add a new warning without a flag, this test will fail.  To fix
     this test, simply add a warning group to that warning.
 
 
 The list of warnings below should NEVER grow.  It should gradually shrink to 0.
 
-CHECK: Warnings without flags (66):
+CHECK: Warnings without flags (65):
 
 CHECK-NEXT:   ext_expected_semi_decl_list
 CHECK-NEXT:   ext_explicit_specialization_storage_class
 CHECK-NEXT:   ext_missing_whitespace_after_macro_name
 CHECK-NEXT:   ext_new_paren_array_nonconst
 CHECK-NEXT:   ext_plain_complex
 CHECK-NEXT:   ext_template_arg_extra_parens
 CHECK-NEXT:   ext_typecheck_cond_incompatible_operands

 CHECK-NEXT:   warn_char_constant_too_large
 CHECK-NEXT:   warn_collection_expr_type
 CHECK-NEXT:   warn_conflicting_variadic
 CHECK-NEXT:   warn_delete_array_type
 CHECK-NEXT:   warn_double_const_requires_fp64
 CHECK-NEXT:   warn_drv_assuming_mfloat_abi_is
 CHECK-NEXT:   warn_drv_clang_unsupported
 CHECK-NEXT:   warn_drv_pch_not_first_include
-CHECK-NEXT:   warn_dup_category_def
 CHECK-NEXT:   warn_enum_value_overflow
 CHECK-NEXT:   warn_expected_qualified_after_typename
 CHECK-NEXT:   warn_fe_backend_unsupported
 CHECK-NEXT:   warn_fe_cc_log_diagnostics_failure
 CHECK-NEXT:   warn_fe_cc_print_header_failure
 CHECK-NEXT:   warn_fe_macro_contains_embedded_newline
 CHECK-NEXT:   warn_ignoring_ftabstop_value
 CHECK-NEXT:   warn_implements_nscopying

clang/test/SemaObjC/check-dup-objc-decls-1.m

 // RUN: %clang_cc1 -fsyntax-only -verify -Wno-objc-root-class %s
+// RUN: %clang_cc1 -fsyntax-only -verify -Wno-objc-root-class -Wno-objc-duplicate-category-definition -DIGNORE_DUP_CAT %s
 
 @interface Foo // expected-note {{previous definition is here}}
 @end
 
 float Foo;  // expected-error {{redefinition of 'Foo' as different kind of symbol}}
 
 @class Bar;  // expected-note {{previous definition is here}}
 

 @protocol PP<Q> @end  // expected-warning {{duplicate protocol definition of 'PP'}}
 
 @protocol DP<P> @end
 #pragma clang diagnostic push
 #pragma clang diagnostic ignored "-Wduplicate-protocol"
 @protocol DP<Q> @end
 #pragma clang diagnostic pop
 
-@interface A(Cat)<P> @end // expected-note {{previous definition is here}}
-@interface A(Cat)<Q> @end // expected-warning {{duplicate definition of category 'Cat' on interface 'A'}}
+@interface A(Cat)<P> @end
+@interface A(Cat)<Q> @end
+
+#ifndef IGNORE_DUP_CAT
+// expected-note@-4 {{previous definition is here}}
+// expected-warning@-4 {{duplicate definition of category 'Cat' on interface 'A'}}
+#endif
 
 // rdar 7626768
 @class NSString;
 NSString * TestBaz;  // expected-note {{previous definition is here}}
 NSString * const TestBaz;  // expected-error {{redefinition of 'TestBaz' with a different type}}