diff --git a/llvm/examples/ThinLtoJIT/ModuleIndex.cpp b/llvm/examples/ThinLtoJIT/ModuleIndex.cpp
--- a/llvm/examples/ThinLtoJIT/ModuleIndex.cpp
+++ b/llvm/examples/ThinLtoJIT/ModuleIndex.cpp
@@ -425,7 +425,7 @@
     if (GlobalValueSummary *S = getSummary(Guid)) {
       ModuleInfo &MI = MIs[S->modulePath()];
 
-      // TODO: Infer symbol flags from the ThinLTO module summary.
+      MI.SymbolFlags[KV.first] = JITSymbolFlags::fromSummary(S);
       MI.Guids.push_back(Guid);
 
       if (!isa<FunctionSummary>(S))
diff --git a/llvm/include/llvm/ExecutionEngine/JITSymbol.h b/llvm/include/llvm/ExecutionEngine/JITSymbol.h
--- a/llvm/include/llvm/ExecutionEngine/JITSymbol.h
+++ b/llvm/include/llvm/ExecutionEngine/JITSymbol.h
@@ -30,6 +30,7 @@
 namespace llvm {
 
 class GlobalValue;
+class GlobalValueSummary;
 
 namespace object {
 
@@ -161,6 +162,10 @@
   /// value.
   static JITSymbolFlags fromGlobalValue(const GlobalValue &GV);
 
+  /// Construct a JITSymbolFlags value based on the flags of the given global
+  /// value summary.
+  static JITSymbolFlags fromSummary(GlobalValueSummary *S);
+
   /// Construct a JITSymbolFlags value based on the flags of the given libobject
   /// symbol.
   static Expected<JITSymbolFlags>
diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/JITSymbol.cpp b/llvm/lib/ExecutionEngine/RuntimeDyld/JITSymbol.cpp
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/JITSymbol.cpp
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/JITSymbol.cpp
@@ -14,6 +14,7 @@
 #include "llvm/IR/Function.h"
 #include "llvm/IR/GlobalAlias.h"
 #include "llvm/IR/GlobalValue.h"
+#include "llvm/IR/ModuleSummaryIndex.h"
 #include "llvm/Object/ObjectFile.h"
 
 using namespace llvm;
@@ -36,6 +37,22 @@
   return Flags;
 }
 
+JITSymbolFlags llvm::JITSymbolFlags::fromSummary(GlobalValueSummary *S) {
+  JITSymbolFlags Flags = JITSymbolFlags::None;
+  auto L = S->linkage();
+  if (GlobalValue::isWeakLinkage(L) || GlobalValue::isLinkOnceLinkage(L))
+    Flags |= JITSymbolFlags::Weak;
+  if (GlobalValue::isCommonLinkage(L))
+    Flags |= JITSymbolFlags::Common;
+  if (GlobalValue::isExternalLinkage(L) || GlobalValue::isExternalWeakLinkage(L))
+    Flags |= JITSymbolFlags::Exported;
+
+  if (isa<FunctionSummary>(S))
+    Flags |= JITSymbolFlags::Callable;
+
+  return Flags;
+}
+
 Expected<JITSymbolFlags>
 llvm::JITSymbolFlags::fromObjectSymbol(const object::SymbolRef &Symbol) {
   JITSymbolFlags Flags = JITSymbolFlags::None;