[Diagnostics] Hooking up remarks emitted from Clang. (#25585)

Now that Swift support remarks ClangImporter we pass them
to the Clang diagnostic producer instead of ignoring them.

Fixes SR-10915

Author: vguerra

include/swift/AST/DiagnosticsClangImporter.def

@@ -17,8 +17,8 @@
 //
 //===----------------------------------------------------------------------===//
 
-#if !(defined(DIAG) || (defined(ERROR) && defined(WARNING) && defined(NOTE)))
-#  error Must define either DIAG or the set {ERROR,WARNING,NOTE}
+#if !(defined(DIAG) || (defined(ERROR) && defined(WARNING) && defined(NOTE) && defined(REMARK)))
+#  error Must define either DIAG or the set {ERROR,WARNING,NOTE,REMARK}
 #endif
 
 #ifndef ERROR
@@ -36,12 +36,19 @@
   DIAG(NOTE,ID,Options,Text,Signature)
 #endif
 
+#ifndef REMARK
+#  define REMARK(ID,Options,Text,Signature) \
+  DIAG(REMARK,ID,Options,Text,Signature)
+#endif
+
 WARNING(warning_from_clang,none,
   "%0", (StringRef))
 ERROR(error_from_clang,none,
   "%0", (StringRef))
 NOTE(note_from_clang,none,
   "%0", (StringRef))
+REMARK(remark_from_clang,none,
+  "%0", (StringRef))
 
 ERROR(clang_cannot_build_module,Fatal,
   "could not build %select{C|Objective-C}0 module '%1'", (bool, StringRef))

lib/ClangImporter/ClangDiagnosticConsumer.cpp

@@ -227,8 +227,8 @@ void ClangDiagnosticConsumer::HandleDiagnostic(
       diagKind = diag::note_from_clang;
       break;
     case clang::DiagnosticsEngine::Remark:
-      // FIXME: We don't handle remarks yet.
-      return;
+      diagKind = diag::remark_from_clang;
+      break;
     case clang::DiagnosticsEngine::Warning:
       diagKind = diag::warning_from_clang;
       break;

test/ClangImporter/remarks.swift

@@ -0,0 +1,6 @@
+// RUN: %target-swift-frontend -typecheck %s -Xcc -Rmodule-import -I %S/Inputs/custom-modules 2>&1 | %FileCheck %s
+
+import Requires.Swift
+// CHECK-NOT: error
+// CHECK: remark: importing module 'SwiftShims'
+// CHECK-NEXT: remark: importing module 'Requires'