3 files changed, 54 insertions, 3 deletions

diff --git a/include/llvm/TableGen/Record.h b/include/llvm/TableGen/Record.h
index d4bc5572482..8c5452e511c 100644
--- a/include/llvm/TableGen/Record.h
+++ b/include/llvm/TableGen/Record.h
@@ -1401,6 +1401,18 @@ class Record {
   DefInit *TheInit;
   bool IsAnonymous;
 
+  // Class-instance values can be used by other defs.  For example, Struct<i>
+  // is used here as a template argument to another class:
+  //
+  //   multiclass MultiClass<int i> {
+  //     def Def : Class<Struct<i>>;
+  //
+  // These need to get fully resolved before instantiating any other
+  // definitions that usie them (e.g. Def).  However, inside a multiclass they
+  // can't be immediately resolved so we mark them ResolveFirst to fully
+  // resolve them later as soon as the multiclass is instantiated.
+  bool ResolveFirst;
+
   void init();
   void checkName();
 
@@ -1409,13 +1421,15 @@ public:
   explicit Record(const std::string &N, ArrayRef<SMLoc> locs,
                   RecordKeeper &records, bool Anonymous = false) :
     ID(LastID++), Name(StringInit::get(N)), Locs(locs.begin(), locs.end()),
-    TrackedRecords(records), TheInit(nullptr), IsAnonymous(Anonymous) {
+    TrackedRecords(records), TheInit(nullptr), IsAnonymous(Anonymous),
+    ResolveFirst(false) {
     init();
   }
   explicit Record(Init *N, ArrayRef<SMLoc> locs, RecordKeeper &records,
                   bool Anonymous = false) :
     ID(LastID++), Name(N), Locs(locs.begin(), locs.end()),
-    TrackedRecords(records), TheInit(nullptr), IsAnonymous(Anonymous) {
+    TrackedRecords(records), TheInit(nullptr), IsAnonymous(Anonymous),
+    ResolveFirst(false) {
     init();
   }
 
@@ -1425,7 +1439,8 @@ public:
     ID(LastID++), Name(O.Name), Locs(O.Locs), TemplateArgs(O.TemplateArgs),
     Values(O.Values), SuperClasses(O.SuperClasses),
     SuperClassRanges(O.SuperClassRanges), TrackedRecords(O.TrackedRecords),
-    TheInit(O.TheInit), IsAnonymous(O.IsAnonymous) { }
+    TheInit(O.TheInit), IsAnonymous(O.IsAnonymous),
+    ResolveFirst(O.ResolveFirst) { }
 
   ~Record() {}
 
@@ -1553,6 +1568,14 @@ public:
     return IsAnonymous;
   }
 
+  bool isResolveFirst() const {
+    return ResolveFirst;
+  }
+
+  void setResolveFirst(bool b) {
+    ResolveFirst = b;
+  }
+
   void dump() const;
 
   //===--------------------------------------------------------------------===//
diff --git a/lib/TableGen/TGParser.cpp b/lib/TableGen/TGParser.cpp
index 15039792042..f2910019ed9 100644
--- a/lib/TableGen/TGParser.cpp
+++ b/lib/TableGen/TGParser.cpp
@@ -1264,6 +1264,9 @@ Init *TGParser::ParseSimpleValue(Record *CurRec, RecTy *ItemType,
       NewRec->resolveReferences();
       Records.addDef(NewRec);
     } else {
+      // This needs to get resolved once the multiclass template arguments are
+      // known before any use.
+      NewRec->setResolveFirst(true);
       // Otherwise, we're inside a multiclass, add it to the multiclass.
       CurMultiClass->DefPrototypes.push_back(NewRec);
 
@@ -2602,6 +2605,12 @@ bool TGParser::ParseDefm(MultiClass *CurMultiClass) {
       if (ResolveMulticlassDef(*MC, CurRec, DefProto, DefmLoc))
         return Error(SubClassLoc, "could not instantiate def");
 
+      // Defs that can be used by other definitions should be fully resolved
+      // before any use.
+      if (DefProto->isResolveFirst() && !CurMultiClass) {
+        CurRec->resolveReferences();
+        CurRec->setResolveFirst(false);
+      }
       NewRecDefs.push_back(CurRec);
     }
 
diff --git a/test/TableGen/ClassInstanceValue.td b/test/TableGen/ClassInstanceValue.td
new file mode 100644
index 00000000000..b6c4c93cb09
--- /dev/null
+++ b/test/TableGen/ClassInstanceValue.td
@@ -0,0 +1,19 @@
+// RUN: llvm-tblgen %s | FileCheck %s
+// XFAIL: vg_leak
+
+class Struct<int i> {
+  int I = !shl(i, 1);
+  int J = !shl(I, 1);
+}
+
+class Class<Struct s> {
+    int Class_J = s.J;
+}
+
+multiclass MultiClass<int i> {
+  def Def : Class<Struct<i>>;
+// CHECK: Class_J = 8
+// CHECK-NOT: Class_J = !shl(I, 1)
+}
+
+defm Defm : MultiClass<2>;