TableGen: Fix type deduction for !foreach

[nhaehnle]

Summary

In the case of !foreach(id, input-list, transform) where the type of
input-list is list<A> and the type of transform is B, we now correctly
deduce list<B> as the type of the !foreach.

Change-Id: Ia19dd65eecc5991dd648280ba6a15f6a20fd61de

llvm/trunk/lib/TableGen/TGParser.cpp

case tgtok::XSubst: {  // Value ::= !ternop '(' Value ',' Value ',' Value ')'
     }
     case tgtok::XForEach: {
       TypedInit *MHSt = dyn_cast<TypedInit>(MHS);
       if (!MHSt) {
         TokError("could not get type for !foreach");
         return nullptr;
       }
       Type = MHSt->getType();
+      if (isa<ListRecTy>(Type)) {
+        TypedInit *RHSt = dyn_cast<TypedInit>(RHS);
+        if (!RHSt) {
+          TokError("could not get type of !foreach list elements");
+          return nullptr;
+        }
+        Type = RHSt->getType()->getListTy();
+      }
       break;
     }
     case tgtok::XSubst: {
       TypedInit *RHSt = dyn_cast<TypedInit>(RHS);
       if (!RHSt) {
         TokError("could not get type for !subst");
         return nullptr;
       }

llvm/trunk/test/TableGen/foreach.td

 // RUN: llvm-tblgen %s | FileCheck %s
 // XFAIL: vg_leak
 
 // CHECK: Classes
 // CHECK: Sr
 // CHECK: Jr
 // CHECK: "NAME"
 
 // CHECK: Defs
+
+// CHECK: def DX {
+// CHECK:   list<string> x = ["0", "1", "2"];
+// CHECK: }
+
 // CHECK: Jr
 // CHECK: Sr
 
 // Variables for foreach
 class decls {
   string name;
+  int num;
 }
 
 def Decls : decls;
 
 class A<list<string> names> {
   list<string> Names = names;
 }
 
 class B<list<string> names> : A<!foreach(Decls.name, names, !strconcat(Decls.name, ", Sr."))>;
 
 class C<list<string> names> : A<!foreach(Decls.name, names, !strconcat(Decls.name, ", Jr."))>;
 
 class D<list<string> names> : A<!foreach(Decls.name, names, !subst("NAME", "John Smith", Decls.name))>;
 
 class Names {
   list<string> values = ["Ken Griffey", "Seymour Cray"];
 }
 
 def People : Names;
 
 def Seniors : B<People.values>;
 def Juniors : C<People.values>;
 def Smiths : D<["NAME", "Jane Smith"]>;
 def Unprocessed : D<People.values>;
+
+class X<list<int> a> {
+    list<string> x = !foreach(Decls.num, a, !cast<string>(Decls.num));
+}
+
+def DX : X<[0, 1, 2]>;