[TableGen] Don't assert, produce an error, when an instruction has too few operands

When an instruction's operand list does not have a sufficient number of
operands to match with all of the variables that contribute to its
encoding, instead of asserting inside a call to getSubOperandNumber, produce an
informative error.

llvm-svn: 204542

1 files changed, 12 insertions, 1 deletions

diff --git a/llvm/utils/TableGen/CodeEmitterGen.cpp b/llvm/utils/TableGen/CodeEmitterGen.cpp
index a7fca06cf0f..c28b97e0420 100644
--- a/llvm/utils/TableGen/CodeEmitterGen.cpp
+++ b/llvm/utils/TableGen/CodeEmitterGen.cpp
@@ -107,9 +107,20 @@ AddCodeToMergeInOperand(Record *R, BitsInit *BI, const std::string &VarName,
     while (NumberedOp < NumberOps &&
            (CGI.Operands.isFlatOperandNotEmitted(NumberedOp) ||
               (NamedOpIndices.size() && NamedOpIndices.count(
-                CGI.Operands.getSubOperandNumber(NumberedOp).first))))
+                CGI.Operands.getSubOperandNumber(NumberedOp).first)))) {
       ++NumberedOp;
 
+      if (NumberedOp >= CGI.Operands.back().MIOperandNo +
+                        CGI.Operands.back().MINumOperands) {
+        errs() << "Too few operands in record " << R->getName() <<
+                  " (no match for variable " << VarName << "):\n";
+        errs() << *R;
+        errs() << '\n';
+
+        return;
+      }
+    }
+
     OpIdx = NumberedOp++;
   }