TableGen: Explicitly forbid some nestings of class, multiclass, and foreach

These previously all failed one way or another, but now we produce a more
helpful error message.

Change-Id: I8ffd2e87c8e35a5134c3be289e0a1fecaa2bb8ca

Differential revision: https://reviews.llvm.org/D44115

llvm-svn: 327497

1 files changed, 10 insertions, 2 deletions

diff --git a/llvm/lib/TableGen/TGParser.cpp b/llvm/lib/TableGen/TGParser.cpp
index d7336231e6e..3bf99e943bc 100644
--- a/llvm/lib/TableGen/TGParser.cpp
+++ b/llvm/lib/TableGen/TGParser.cpp
@@ -3143,8 +3143,16 @@ bool TGParser::ParseObject(MultiClass *MC) {
     if (MC)
       return TokError("defset is not allowed inside multiclass");
     return ParseDefset();
-  case tgtok::Class: return ParseClass();
-  case tgtok::MultiClass: return ParseMultiClass();
+  case tgtok::Class:
+    if (MC)
+      return TokError("class is not allowed inside multiclass");
+    if (!Loops.empty())
+      return TokError("class is not allowed inside foreach loop");
+    return ParseClass();
+  case tgtok::MultiClass:
+    if (!Loops.empty())
+      return TokError("multiclass is not allowed inside foreach loop");
+    return ParseMultiClass();
   }
 }