Index: include/llvm/Linker/IRMover.h
===================================================================
--- include/llvm/Linker/IRMover.h
+++ include/llvm/Linker/IRMover.h
@@ -60,7 +60,7 @@
     bool hasType(StructType *Ty);
   };
 
-  IRMover(Module &M);
+  IRMover(Module &M, bool OnlyNamedTypes = false);
 
   typedef std::function<void(GlobalValue &)> ValueAdder;
 
Index: include/llvm/Linker/Linker.h
===================================================================
--- include/llvm/Linker/Linker.h
+++ include/llvm/Linker/Linker.h
@@ -30,9 +30,10 @@
     None = 0,
     OverrideFromSrc = (1 << 0),
     LinkOnlyNeeded = (1 << 1),
+    DontLinkUnnamedTypes = (1 << 2),
   };
 
-  Linker(Module &M);
+  Linker(Module &M, bool OnlyNamedTypes = false);
 
   /// \brief Link \p Src into the composite.
   ///
Index: lib/Linker/IRMover.cpp
===================================================================
--- lib/Linker/IRMover.cpp
+++ lib/Linker/IRMover.cpp
@@ -1411,9 +1411,9 @@
   return I == NonOpaqueStructTypes.end() ? false : *I == Ty;
 }
 
-IRMover::IRMover(Module &M) : Composite(M) {
+IRMover::IRMover(Module &M, bool OnlyNamedTypes) : Composite(M) {
   TypeFinder StructTypes;
-  StructTypes.run(M, /* OnlyNamed */ false);
+  StructTypes.run(M, OnlyNamedTypes);
   for (StructType *Ty : StructTypes) {
     if (Ty->isOpaque())
       IdentifiedStructTypes.addOpaque(Ty);
Index: lib/Linker/LinkModules.cpp
===================================================================
--- lib/Linker/LinkModules.cpp
+++ lib/Linker/LinkModules.cpp
@@ -559,7 +559,8 @@
   return false;
 }
 
-Linker::Linker(Module &M) : Mover(M) {}
+Linker::Linker(Module &M, bool OnlyNamedTypes) :
+  Mover(M, OnlyNamedTypes) {}
 
 bool Linker::linkInModule(
     std::unique_ptr<Module> Src, unsigned Flags,
@@ -581,7 +582,8 @@
 bool Linker::linkModules(
     Module &Dest, std::unique_ptr<Module> Src, unsigned Flags,
     std::function<void(Module &, const StringSet<> &)> InternalizeCallback) {
-  Linker L(Dest);
+  bool OnlyNamedTypes = (Flags & DontLinkUnnamedTypes) != 0;
+  Linker L(Dest, OnlyNamedTypes);
   return L.linkInModule(std::move(Src), Flags, std::move(InternalizeCallback));
 }
 
Index: tools/llvm-link/llvm-link.cpp
===================================================================
--- tools/llvm-link/llvm-link.cpp
+++ tools/llvm-link/llvm-link.cpp
@@ -97,6 +97,10 @@
 DumpAsm("d", cl::desc("Print assembly as linked"), cl::Hidden);
 
 static cl::opt<bool>
+NoLinkUnnamedTypes("no-link-unnamed", cl::desc("Don't link unnamed types"),
+                   cl::Hidden);
+
+static cl::opt<bool>
 SuppressWarnings("suppress-warnings", cl::desc("Suppress all linking warnings"),
                  cl::init(false));
 
@@ -361,6 +365,8 @@
   unsigned Flags = Linker::Flags::None;
   if (OnlyNeeded)
     Flags |= Linker::Flags::LinkOnlyNeeded;
+  if (NoLinkUnnamedTypes)
+    Flags |= Linker::Flags::DontLinkUnnamedTypes;
 
   // First add all the regular input files
   if (!linkFiles(argv[0], Context, L, InputFilenames, Flags))