diff --git a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
--- a/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
+++ b/llvm/lib/Bitcode/Reader/MetadataLoader.cpp
@@ -2078,8 +2078,15 @@
   case bitc::METADATA_ARG_LIST: {
     SmallVector<ValueAsMetadata *, 4> Elts;
     Elts.reserve(Record.size());
-    for (uint64_t Elt : Record)
-      Elts.push_back(dyn_cast_or_null<ValueAsMetadata>(getMDOrNull(Elt)));
+    for (uint64_t Elt : Record) {
+      Metadata *MD = getMD(Elt);
+      if (isa<MDNode>(MD) && cast<MDNode>(MD)->isTemporary())
+        return error(
+            "Invalid record: DIArgList should not contain forward refs");
+      if (!isa<ValueAsMetadata>(MD))
+        return error("Invalid record");
+      Elts.push_back(cast<ValueAsMetadata>(MD));
+    }
 
     MetadataList.assignValue(DIArgList::get(Context, Elts), NextMetadataNo);
     NextMetadataNo++;
diff --git a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
--- a/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
+++ b/llvm/lib/Bitcode/Writer/BitcodeWriter.cpp
@@ -1876,7 +1876,7 @@
                                          unsigned Abbrev) {
   Record.reserve(N->getArgs().size());
   for (ValueAsMetadata *MD : N->getArgs())
-    Record.push_back(VE.getMetadataOrNullID(MD));
+    Record.push_back(VE.getMetadataID(MD));
 
   Stream.EmitRecord(bitc::METADATA_ARG_LIST, Record, Abbrev);
   Record.clear();
diff --git a/llvm/lib/Bitcode/Writer/ValueEnumerator.h b/llvm/lib/Bitcode/Writer/ValueEnumerator.h
--- a/llvm/lib/Bitcode/Writer/ValueEnumerator.h
+++ b/llvm/lib/Bitcode/Writer/ValueEnumerator.h
@@ -27,6 +27,7 @@
 
 class BasicBlock;
 class Comdat;
+class DIArgList;
 class Function;
 class Instruction;
 class LocalAsMetadata;
@@ -286,6 +287,9 @@
   void EnumerateFunctionLocalMetadata(const Function &F,
                                       const LocalAsMetadata *Local);
   void EnumerateFunctionLocalMetadata(unsigned F, const LocalAsMetadata *Local);
+  void EnumerateFunctionLocalListMetadata(const Function &F,
+                                          const DIArgList *ArgList);
+  void EnumerateFunctionLocalListMetadata(unsigned F, const DIArgList *Arglist);
   void EnumerateNamedMDNode(const NamedMDNode *NMD);
   void EnumerateValue(const Value *V);
   void EnumerateType(Type *T);
diff --git a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
--- a/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
+++ b/llvm/lib/Bitcode/Writer/ValueEnumerator.cpp
@@ -620,6 +620,11 @@
   EnumerateFunctionLocalMetadata(getMetadataFunctionID(&F), Local);
 }
 
+void ValueEnumerator::EnumerateFunctionLocalListMetadata(
+    const Function &F, const DIArgList *ArgList) {
+  EnumerateFunctionLocalListMetadata(getMetadataFunctionID(&F), ArgList);
+}
+
 void ValueEnumerator::dropFunctionFromMetadata(
     MetadataMapType::value_type &FirstMD) {
   SmallVector<const MDNode *, 64> Worklist;
@@ -730,7 +735,7 @@
   return nullptr;
 }
 
-/// EnumerateFunctionLocalMetadataa - Incorporate function-local metadata
+/// EnumerateFunctionLocalMetadata - Incorporate function-local metadata
 /// information reachable from the metadata.
 void ValueEnumerator::EnumerateFunctionLocalMetadata(
     unsigned F, const LocalAsMetadata *Local) {
@@ -750,6 +755,37 @@
   EnumerateValue(Local->getValue());
 }
 
+/// EnumerateFunctionLocalListMetadata - Incorporate function-local metadata
+/// information reachable from the metadata.
+void ValueEnumerator::EnumerateFunctionLocalListMetadata(
+    unsigned F, const DIArgList *ArgList) {
+  assert(F && "Expected a function");
+
+  // Check to see if it's already in!
+  MDIndex &Index = MetadataMap[ArgList];
+  if (Index.ID) {
+    assert(Index.F == F && "Expected the same function");
+    return;
+  }
+
+  for (ValueAsMetadata *Value : ArgList->getArgs()) {
+    if (isa<LocalAsMetadata>(Value)) {
+      assert(MetadataMap.count(Value) &&
+             "LocalAsMetadata should be enumerated before DIArgList");
+      assert(MetadataMap[Value].F == F &&
+             "Expected LocalAsMetadata in the same function");
+    } else {
+      assert(isa<ConstantAsMetadata>(Value) &&
+             "Expected LocalAsMetadata or ConstantAsMetadata");
+      EnumerateMetadata(F, Value);
+    }
+  }
+
+  MDs.push_back(ArgList);
+  Index.F = F;
+  Index.ID = MDs.size();
+}
+
 static unsigned getMetadataTypeOrder(const Metadata *MD) {
   // Strings are emitted in bulk and must come first.
   if (isa<MDString>(MD))
@@ -1072,7 +1108,7 @@
   // DIArgList entries must come after function-local metadata, as it is not
   // possible to forward-reference them.
   for (const DIArgList *ArgList : ArgListMDVector)
-    EnumerateMetadata(&F, ArgList);
+    EnumerateFunctionLocalListMetadata(F, ArgList);
 }
 
 void ValueEnumerator::purgeFunction() {