Add a better error message when failing to assign one tablegen value to another

This is currently for assigning from one bit init to another.  It can easily be extended to other types.

Test to follow soon in another patch.

git-svn-id: https://llvm.org/svn/llvm-project/llvm/trunk@214374 91177308-0d34-0410-b5e6-96231b3b80d8

diff --git a/lib/TableGen/TGParser.cpp b/lib/TableGen/TGParser.cpp
index 0550692ebce7ff40f9d2c9084dd5dc42e518c7f7..54932487e8da9edf1fc4a1814f6db2ca4cdbefbe 100644 (file)
--- a/lib/TableGen/TGParser.cpp
+++ b/lib/TableGen/TGParser.cpp
@@ -135,11 +135,18 @@ bool TGParser::SetValue(Record *CurRec, SMLoc Loc, Init *ValName,
     V = BitsInit::get(NewBits);
   }
 
-  if (RV->setValue(V))
+  if (RV->setValue(V)) {
+    std::string InitType = "";
+    if (BitsInit *BI = dyn_cast<BitsInit>(V)) {
+      InitType = (Twine("' of type bit initializer with length ") +
+                  Twine(BI->getNumBits())).str();
+    }
     return Error(Loc, "Value '" + ValName->getAsUnquotedString() + "' of type '"
                  + RV->getType()->getAsString() +
                  "' is incompatible with initializer '" + V->getAsString()
+                 + InitType
                  + "'");
+  }
   return false;
 }