[TableGen] Don't quote variable name when printing !foreach.

[simon_tatham]

Summary

An input !foreach expression such as !foreach(a, lst, !add(a, 1))
would be re-emitted by llvm-tblgen -print-records with the first
argument in quotes, giving !foreach("a", lst, !add(a, 1)), which isn't
valid TableGen input syntax.

[simon_tatham]

I happened to notice this minor discrepancy in the course of writing the original version of D46054 (which dumped all the interesting unresolved expression nodes as well as the concrete final values). It's not important, I admit, but it briefly confused me about what the right syntax for !foreach was, so I thought it would be worth fixing for that reason alone.

[nhaehnle]

Good catch! I agree that this is a very useful change.

lib/TableGen/Record.cpp

Init *TernOpInit::resolveReferences(Resolver &R) const {
   if (LHS != lhs || MHS != mhs || RHS != rhs)
     return (TernOpInit::get(getOpcode(), lhs, mhs, rhs, getType()))
         ->Fold(R.getCurrentRecord());
   return const_cast<TernOpInit *>(this);
 }
 
 std::string TernOpInit::getAsString() const {
   std::string Result;
+  bool UnquotedLHS = false;
   switch (getOpcode()) {
   case SUBST: Result = "!subst"; break;
-  case FOREACH: Result = "!foreach"; break;
+  case FOREACH: Result = "!foreach"; UnquotedLHS = true; break;
   case IF: Result = "!if"; break;
   case DAG: Result = "!dag"; break;
   }
-  return Result + "(" + LHS->getAsString() + ", " + MHS->getAsString() + ", " +
-         RHS->getAsString() + ")";
+  return (Result + "(" +
+          (UnquotedLHS ? LHS->getAsUnquotedString() : LHS->getAsString()) +
+          ", " + MHS->getAsString() + ", " + RHS->getAsString() + ")");
 }
 
 static void ProfileFoldOpInit(FoldingSetNodeID &ID, Init *A, Init *B,
                               Init *Start, Init *List, Init *Expr,
                               RecTy *Type) {
   ID.AddPointer(Start);
   ID.AddPointer(List);
   ID.AddPointer(A);

test/TableGen/foreach-leak.td

 // RUN: llvm-tblgen %s | FileCheck %s
 // XFAIL: vg_leak
 
+// CHECK: --- Classes ---
+// CHECK: list<int> ret = !foreach(a,
+
 // CHECK: --- Defs ---
 
 // CHECK: def C0 {
 // CHECK:   list<list<int>> ret = {{\[}}[1, 2, 3], [1, 2, 3]];
 // CHECK: }
 
 // The variable name 'a' is used both in the "inner" and in the "outer" foreach.
 // The test ensure that the inner declaration of 'a' properly shadows the outer