From 4b211b94d71386d249e2004c817a9bb659634c2b Mon Sep 17 00:00:00 2001
From: Jacques Pienaar <jpienaar@google.com>
Date: Sun, 9 Aug 2020 18:02:08 -0700
Subject: [PATCH] [mlir][drr] Make error easier to understand

Changes error from
  error: referencing unbound symbol ''
to
  error: raw string not supported as argument
---
 mlir/tools/mlir-tblgen/RewriterGen.cpp | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/mlir/tools/mlir-tblgen/RewriterGen.cpp b/mlir/tools/mlir-tblgen/RewriterGen.cpp
index fc67ec4b8c174..5025ee5216dd6 100644
--- a/mlir/tools/mlir-tblgen/RewriterGen.cpp
+++ b/mlir/tools/mlir-tblgen/RewriterGen.cpp
@@ -734,6 +734,8 @@ std::string PatternEmitter::handleLocationDirective(DagNode tree) {
 
 std::string PatternEmitter::handleOpArgument(DagLeaf leaf,
                                              StringRef patArgName) {
+  if (leaf.isStringAttr())
+    PrintFatalError(loc, "raw string not supported as argument");
   if (leaf.isConstantAttr()) {
     auto constAttr = leaf.getAsConstantAttr();
     return handleConstantAttr(constAttr.getAttribute(),