diff --git a/llvm/lib/ExecutionEngine/Orc/ObjectLinkingLayer.cpp b/llvm/lib/ExecutionEngine/Orc/ObjectLinkingLayer.cpp
index 161a30e44616..26f77acd91fc 100644
--- a/llvm/lib/ExecutionEngine/Orc/ObjectLinkingLayer.cpp
+++ b/llvm/lib/ExecutionEngine/Orc/ObjectLinkingLayer.cpp
@@ -214,8 +214,9 @@ public:
   Error modifyPassConfig(const Triple &TT, PassConfiguration &Config) override {
     // Add passes to mark duplicate defs as should-discard, and to walk the
     // link graph to build the symbol dependence graph.
-    Config.PrePrunePasses.push_back(
-        [this](LinkGraph &G) { return externalizeWeakAndCommonSymbols(G); });
+    Config.PrePrunePasses.push_back([this](LinkGraph &G) {
+      return claimOrExternalizeWeakAndCommonSymbols(G);
+    });
 
     Layer.modifyPassConfig(*MR, TT, Config);
 
@@ -233,19 +234,38 @@ private:
   using LocalSymbolNamedDependenciesMap =
       DenseMap<const Symbol *, LocalSymbolNamedDependencies>;
 
-  Error externalizeWeakAndCommonSymbols(LinkGraph &G) {
+  Error claimOrExternalizeWeakAndCommonSymbols(LinkGraph &G) {
     auto &ES = Layer.getExecutionSession();
-    for (auto *Sym : G.defined_symbols())
-      if (Sym->hasName() && Sym->getLinkage() == Linkage::Weak) {
-        if (!MR->getSymbols().count(ES.intern(Sym->getName())))
-          G.makeExternal(*Sym);
-      }
 
-    for (auto *Sym : G.absolute_symbols())
+    SymbolFlagsMap NewSymbolsToClaim;
+    std::vector<std::pair<SymbolStringPtr, Symbol *>> NameToSym;
+
+    auto ProcessSymbol = [&](Symbol *Sym) {
       if (Sym->hasName() && Sym->getLinkage() == Linkage::Weak) {
-        if (!MR->getSymbols().count(ES.intern(Sym->getName())))
-          G.makeExternal(*Sym);
+        auto Name = ES.intern(Sym->getName());
+        if (!MR->getSymbols().count(ES.intern(Sym->getName()))) {
+          JITSymbolFlags SF = JITSymbolFlags::Weak;
+          if (Sym->getScope() == Scope::Default)
+            SF |= JITSymbolFlags::Exported;
+          NewSymbolsToClaim[Name] = SF;
+          NameToSym.push_back(std::make_pair(std::move(Name), Sym));
+        }
       }
+    };
+
+    for (auto *Sym : G.defined_symbols())
+      ProcessSymbol(Sym);
+    for (auto *Sym : G.absolute_symbols())
+      ProcessSymbol(Sym);
+
+    // Attempt to claim all weak defs that we're not already responsible for.
+    // This cannot fail -- any clashes will just result in rejection of our
+    // claim, at which point we'll externalize that symbol.
+    cantFail(MR->defineMaterializing(std::move(NewSymbolsToClaim)));
+
+    for (auto &KV : NameToSym)
+      if (!MR->getSymbols().count(KV.first))
+        G.makeExternal(*KV.second);
 
     return Error::success();
   }