[TableGen] Report an error message on a missing comma

[arichardson]

Summary

I recently forgot a comma in a defm argument list and tablegen just
failed with exit code 1 without printing an error message. I believe
this issue was introduced in a9fc44c5573208859c2550382755098d750fc47d.

This change prints the following instead:
.../clang/include/clang/Driver/Options.td:569:3: error: Expected comma before next argument

[arichardson]

Add a test

[Paul-C-Anagnostopoulos]

Yep, this was my mistake. Thanks for fixing it.

Looks good to me.

llvm/lib/TableGen/TGParser.cpp

while (true) {
     ItemType = Arg->getType();
     Init *Value = ParseValue(CurRec, ItemType);
     if (!Value)
       return true;
     Result.push_back(Value);
 
     if (consume(tgtok::greater)) // end of argument list?
       return false;
-    if (!consume(tgtok::comma)) // must be comma
-      return true;
-    ++ArgIndex; 
+    if (!consume(tgtok::comma))
+      return TokError("Expected comma before next argument");
+    ++ArgIndex;
   }
 }
 
 /// ParseDeclaration - Read a declaration, returning the name of field ID, or an
 /// empty string on error.  This can happen in a number of different contexts,
 /// including within a def or in the template args for a class (in which case
 /// CurRec will be non-null) and within the template args for a multiclass (in
 /// which case CurRec will be null, but CurMultiClass will be set).  This can

llvm/test/TableGen/template-args.td

 // RUN: llvm-tblgen %s | FileCheck %s
 // RUN: not llvm-tblgen -DERROR1 %s 2>&1 | FileCheck --check-prefix=ERROR1 %s
 // RUN: not llvm-tblgen -DERROR2 %s 2>&1 | FileCheck --check-prefix=ERROR2 %s
 // RUN: not llvm-tblgen -DERROR3 %s 2>&1 | FileCheck --check-prefix=ERROR3 %s
 // RUN: not llvm-tblgen -DERROR4 %s 2>&1 | FileCheck --check-prefix=ERROR4 %s
 // RUN: not llvm-tblgen -DERROR5 %s 2>&1 | FileCheck --check-prefix=ERROR5 %s
 // RUN: not llvm-tblgen -DERROR6 %s 2>&1 | FileCheck --check-prefix=ERROR6 %s
+// RUN: not llvm-tblgen -DERROR7 %s 2>&1 | FileCheck --check-prefix=ERROR7 %s
 
 // This file tests that template arguments are type-checked and cast
 // if necessary.
 
 // Class template arguments.
 
 class Class1<string nm> {
   string Name = nm;

 
 defm RecMC3 : MC2<42>;
 
 #ifdef ERROR6
 // ERROR6: Value specified for template argument 'MC2::cd' (#0) is of type string
 
 defm RecMC4 : MC2<"Bob">;
 #endif
+
+#ifdef ERROR7
+multiclass TwoArgs<bits<8> a, string b> {
+  def _1 { bits<8> A = a; }
+  def _2 { string B = b; }
+}
+defm Good : TwoArgs<1, "one">;
+defm MissingComma : TwoArgs<2 "two">;
+// ERROR7: [[#@LINE-1]]:31: error: Expected comma before next argument
+#endif