Add DK_Remark to SMDiagnostic

[anemet]

Summary

Swift uses SMDiagnostic for diagnostic messages. For
https://github.com/apple/swift/pull/12294, we need remark support.

I picked the color that clang uses to display them.

[jordan_rose]

Seems reasonable to me. I don't know anything about the MIR parser's use of diagnostics, though.

[anemet]

Seems reasonable to me. I don't know anything about the MIR parser's use of diagnostics, though.

Currently it does not emit remarks and we can introduce remarks as needed. Thanks for the review!

llvm/trunk/include/llvm/Support/SourceMgr.h

 
 /// This owns the files read by a parser, handles include stacks,
 /// and handles diagnostic wrangling.
 class SourceMgr {
 public:
   enum DiagKind {
     DK_Error,
     DK_Warning,
-    DK_Note
+    DK_Remark,
+    DK_Note,
   };
 
   /// Clients that want to handle their own diagnostics in a custom way can
   /// register a function pointer+context as a diagnostic handler.
   /// It gets called each time PrintMessage is invoked.
   using DiagHandlerTy = void (*)(const SMDiagnostic &, void *Context);
 
 private:

llvm/trunk/lib/CodeGen/MIRParser/MIRParser.cpp

case SourceMgr::DK_Error:
     Kind = DS_Error;
     break;
   case SourceMgr::DK_Warning:
     Kind = DS_Warning;
     break;
   case SourceMgr::DK_Note:
     Kind = DS_Note;
     break;
+  case SourceMgr::DK_Remark:
+    llvm_unreachable("remark unexpected");
+    break;
   }
   Context.diagnose(DiagnosticInfoMIRParser(Kind, Diag));
 }
 
 std::unique_ptr<Module> MIRParserImpl::parseIRModule() {
   if (!In.setCurrentDocument()) {
     if (In.error())
       return nullptr;

llvm/trunk/lib/Support/SourceMgr.cpp

case SourceMgr::DK_Warning:
         S.changeColor(raw_ostream::MAGENTA, true);
       S << "warning: ";
       break;
     case SourceMgr::DK_Note:
       if (ShowColors)
         S.changeColor(raw_ostream::BLACK, true);
       S << "note: ";
       break;
+    case SourceMgr::DK_Remark:
+      if (ShowColors)
+        S.changeColor(raw_ostream::BLUE, true);
+      S << "remark: ";
+      break;
     }
 
     if (ShowColors) {
       S.resetColor();
       S.changeColor(raw_ostream::SAVEDCOLOR, true);
     }
   }
 

llvm/trunk/unittests/Support/SourceMgrTest.cpp

TEST_F(SourceMgrTest, BasicWarning) {
   printMessage(getLoc(4), SourceMgr::DK_Warning, "message", None, None);
 
   EXPECT_EQ("file.in:1:5: warning: message\n"
             "aaa bbb\n"
             "    ^\n",
             Output);
 }
 
+TEST_F(SourceMgrTest, BasicRemark) {
+  setMainBuffer("aaa bbb\nccc ddd\n", "file.in");
+  printMessage(getLoc(4), SourceMgr::DK_Remark, "message", None, None);
+
+  EXPECT_EQ("file.in:1:5: remark: message\n"
+            "aaa bbb\n"
+            "    ^\n",
+            Output);
+}
+
 TEST_F(SourceMgrTest, BasicNote) {
   setMainBuffer("aaa bbb\nccc ddd\n", "file.in");
   printMessage(getLoc(4), SourceMgr::DK_Note, "message", None, None);
 
   EXPECT_EQ("file.in:1:5: note: message\n"
             "aaa bbb\n"
             "    ^\n",
             Output);