Add -Wignored-pragma-intrinsic flag

[agutowski]

Summary

People might want to receive warnings about pragmas but not about intrinsics that are implemented in intrin.h.

[hans]

lgtm!

cfe/trunk/include/clang/Basic/DiagnosticGroups.td

 def UndefinedReinterpretCast : DiagGroup<"undefined-reinterpret-cast">;
 def ReinterpretBaseClass : DiagGroup<"reinterpret-base-class">;
 def Unicode  : DiagGroup<"unicode">;
 def UninitializedMaybe : DiagGroup<"conditional-uninitialized">;
 def UninitializedSometimes : DiagGroup<"sometimes-uninitialized">;
 def UninitializedStaticSelfInit : DiagGroup<"static-self-init">;
 def Uninitialized  : DiagGroup<"uninitialized", [UninitializedSometimes,
                                                  UninitializedStaticSelfInit]>;
+def IgnoredPragmaIntrinsic : DiagGroup<"ignored-pragma-intrinsic">;
 def UnknownPragmas : DiagGroup<"unknown-pragmas">;
-def IgnoredPragmas : DiagGroup<"ignored-pragmas">;
+def IgnoredPragmas : DiagGroup<"ignored-pragmas", [IgnoredPragmaIntrinsic]>;
 def Pragmas : DiagGroup<"pragmas", [UnknownPragmas, IgnoredPragmas]>;
 def UnknownWarningOption : DiagGroup<"unknown-warning-option">;
 def NSobjectAttribute : DiagGroup<"NSObject-attribute">;
 def IndependentClassAttribute : DiagGroup<"IndependentClass-attribute">;
 def UnknownAttributes : DiagGroup<"unknown-attributes">;
 def IgnoredAttributes : DiagGroup<"ignored-attributes">;
 def Attributes : DiagGroup<"attributes", [UnknownAttributes,
                                           IgnoredAttributes]>;

cfe/trunk/include/clang/Basic/DiagnosticParseKinds.td

def warn_pragma_invalid_action : Warning<
   "unknown action for '#pragma %0' - ignored">,
   InGroup<IgnoredPragmas>;
 def warn_pragma_pack_malformed : Warning<
   "expected integer or identifier in '#pragma pack' - ignored">,
   InGroup<IgnoredPragmas>;
 // - #pragma intrinsic
 def warn_pragma_intrinsic_builtin : Warning<
   "%0 is not a recognized builtin%select{|; consider including <intrin.h> to access non-builtin intrinsics}1">,
-  InGroup<IgnoredPragmas>;
+  InGroup<IgnoredPragmaIntrinsic>;
 // - #pragma unused
 def warn_pragma_unused_expected_var : Warning<
   "expected '#pragma unused' argument to be a variable name">,
   InGroup<IgnoredPragmas>;
 // - #pragma init_seg
 def warn_pragma_init_seg_unsupported_target : Warning<
   "'#pragma init_seg' is only supported when targeting a "
   "Microsoft environment">,

cfe/trunk/test/Preprocessor/pragma_microsoft.c

 #pragma intrinsic(int) // expected-warning {{missing ')' after}}
 #pragma intrinsic(strcmp) asdf // expected-warning {{extra tokens at end}}
 
 #define __INTRIN_H  // there should be no notes after defining __INTRIN_H
 #pragma intrinsic(asdf) // expected-warning-re {{'asdf' is not a recognized builtin{{$}}}}
 #pragma intrinsic(memset) // no-warning
 #undef __INTRIN_H
 #pragma intrinsic(asdf) // expected-warning {{'asdf' is not a recognized builtin; consider including <intrin.h>}}
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wignored-pragma-intrinsic"
+#pragma intrinsic(asdf) // no-warning
+#pragma clang diagnostic pop
+#pragma intrinsic(asdf) // expected-warning {{'asdf' is not a recognized builtin; consider including <intrin.h>}}
+
+#pragma clang diagnostic push
+#pragma clang diagnostic ignored "-Wignored-pragmas"
+#pragma intrinsic(asdf) // no-warning
+#pragma clang diagnostic pop
+#pragma intrinsic(asdf) // expected-warning {{'asdf' is not a recognized builtin; consider including <intrin.h>}}