Fix getCustomDiagID() usage in CodeGen and TextDiagnosticBuffer

DiagIDs are a cached resource generally only constructed from compile-time
constant or stable format strings.

Escaping arbitrary messages and constructing DiagIDs from them didn't make
sense.

llvm-svn: 197856
diff --git a/clang/lib/CodeGen/CodeGenAction.cpp b/clang/lib/CodeGen/CodeGenAction.cpp
index 6fceabd..8efeba6 100644
--- a/clang/lib/CodeGen/CodeGenAction.cpp
+++ b/clang/lib/CodeGen/CodeGenAction.cpp
@@ -399,24 +399,15 @@
         SM.getFileEntryForID(SM.getMainFileID()), Err.getLineNo(),
         Err.getColumnNo() + 1);
 
-      // Get a custom diagnostic for the error. We strip off a leading
-      // diagnostic code if there is one.
+      // Strip off a leading diagnostic code if there is one.
       StringRef Msg = Err.getMessage();
       if (Msg.startswith("error: "))
         Msg = Msg.substr(7);
 
-      // Escape '%', which is interpreted as a format character.
-      SmallString<128> EscapedMessage;
-      for (unsigned i = 0, e = Msg.size(); i != e; ++i) {
-        if (Msg[i] == '%')
-          EscapedMessage += '%';
-        EscapedMessage += Msg[i];
-      }
+      unsigned DiagID =
+          CI.getDiagnostics().getCustomDiagID(DiagnosticsEngine::Error, "%0");
 
-      unsigned DiagID = CI.getDiagnostics().getCustomDiagID(
-          DiagnosticsEngine::Error, EscapedMessage);
-
-      CI.getDiagnostics().Report(Loc, DiagID);
+      CI.getDiagnostics().Report(Loc, DiagID) << Msg;
       return;
     }
     const TargetOptions &TargetOpts = CI.getTargetOpts();