diff --git a/llvm/include/llvm/IR/ModuleSummaryIndex.h b/llvm/include/llvm/IR/ModuleSummaryIndex.h
--- a/llvm/include/llvm/IR/ModuleSummaryIndex.h
+++ b/llvm/include/llvm/IR/ModuleSummaryIndex.h
@@ -1465,10 +1465,15 @@
   /// Convenience method for creating a promoted global name
   /// for the given value name of a local, and its original module's ID.
   static std::string getGlobalNameForLocal(StringRef Name, ModuleHash ModHash) {
+    std::string Suffix = utostr((uint64_t(ModHash[0]) << 32) |
+                                ModHash[1]); // Take the first 64 bits
+    return getGlobalNameForLocal(Name, Suffix);
+  }
+
+  static std::string getGlobalNameForLocal(StringRef Name, StringRef Suffix) {
     SmallString<256> NewName(Name);
     NewName += ".llvm.";
-    NewName += utostr((uint64_t(ModHash[0]) << 32) |
-                      ModHash[1]); // Take the first 64 bits
+    NewName += Suffix;
     return std::string(NewName.str());
   }
 
diff --git a/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp b/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp
--- a/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp
+++ b/llvm/lib/Transforms/Utils/FunctionImportUtils.cpp
@@ -12,8 +12,18 @@
 //===----------------------------------------------------------------------===//
 
 #include "llvm/Transforms/Utils/FunctionImportUtils.h"
+#include "llvm/Support/CommandLine.h"
 using namespace llvm;
 
+/// Uses the "source_filename" instead of a Module hash ID for the suffix of
+/// promoted locals during LTO. NOTE: This requires that the source filename
+/// has a unique name / path to avoid name collisions.
+static cl::opt<bool> UseSourceFilenameForPromotedLocals(
+    "use-source-filename-for-promoted-locals", cl::Hidden,
+    cl::desc("Uses the source file name instead of the Module hash. "
+             "This requires that the source filename has a unique name / "
+             "path to avoid name collisions."));
+
 /// Checks if we should import SGV as a definition, otherwise import as a
 /// declaration.
 bool FunctionImportGlobalProcessing::doImportAsDefinition(
@@ -94,9 +104,19 @@
 std::string
 FunctionImportGlobalProcessing::getPromotedName(const GlobalValue *SGV) {
   assert(SGV->hasLocalLinkage());
+
   // For locals that must be promoted to global scope, ensure that
   // the promoted name uniquely identifies the copy in the original module,
   // using the ID assigned during combined index creation.
+  if (UseSourceFilenameForPromotedLocals &&
+      !SGV->getParent()->getSourceFileName().empty()) {
+    SmallString<256> Suffix(SGV->getParent()->getSourceFileName());
+    std::replace_if(std::begin(Suffix), std::end(Suffix),
+                    [&](char ch) { return !isAlnum(ch); }, '_');
+    return ModuleSummaryIndex::getGlobalNameForLocal(
+        SGV->getName(), Suffix);
+  }
+
   return ModuleSummaryIndex::getGlobalNameForLocal(
       SGV->getName(),
       ImportIndex.getModuleHash(SGV->getParent()->getModuleIdentifier()));
diff --git a/llvm/test/ThinLTO/X86/Inputs/promote-local-name-1.ll b/llvm/test/ThinLTO/X86/Inputs/promote-local-name-1.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/ThinLTO/X86/Inputs/promote-local-name-1.ll
@@ -0,0 +1,20 @@
+source_filename = "llvm/test/LTO/X86/promote-local-name-1.ll"
+
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+@baz = internal constant i32 10, align 4
+
+; Function Attrs: noinline nounwind uwtable
+define i32 @b() {
+entry:
+  %call = call i32 @foo()
+  ret i32 %call
+}
+
+; Function Attrs: noinline nounwind uwtable
+define internal i32 @foo() {
+entry:
+  %0 = load i32, i32* @baz, align 4
+  ret i32 %0
+}
diff --git a/llvm/test/ThinLTO/X86/promote-local-name.ll b/llvm/test/ThinLTO/X86/promote-local-name.ll
new file mode 100644
--- /dev/null
+++ b/llvm/test/ThinLTO/X86/promote-local-name.ll
@@ -0,0 +1,33 @@
+; Test the "-use-source-filename-for-promoted-locals" flag.
+
+; Do setup work for all below tests: generate bitcode and combined index
+; RUN: opt -module-summary -module-hash %s -o %t.bc
+; RUN: opt -module-summary -module-hash %p/Inputs/promote-local-name-1.ll -o %t1.bc
+; RUN: llvm-lto -thinlto-action=thinlink -o %t2.bc %t.bc %t1.bc
+
+; This module will import b() which should cause the copy of foo and baz from
+; that module (%t1.bc) to be imported. Check that the imported reference's
+; promoted name matches the imported copy. We check for a specific name,
+; because the result of the "-use-source-filename-for-promoted-locals" flag
+; should be deterministic.
+
+; RUN: llvm-lto -use-source-filename-for-promoted-locals -thinlto-action=import %t.bc -thinlto-index=%t2.bc -o - | llvm-dis -o - | FileCheck %s
+
+; CHECK: @baz.llvm.llvm_test_LTO_X86_promote_local_name_1_ll = internal constant i32 10, align 4
+; CHECK: call i32 @foo.llvm.llvm_test_LTO_X86_promote_local_name_1_ll
+; CHECK: define available_externally hidden i32 @foo.llvm.llvm_test_LTO_X86_promote_local_name_1_ll()
+
+source_filename = "llvm/test/ThinLTO/X86/promote-local-name.ll"
+target datalayout = "e-m:e-p270:32:32-p271:32:32-p272:64:64-i64:64-f80:128-n8:16:32:64-S128"
+target triple = "x86_64-unknown-linux-gnu"
+
+; Function Attrs: noinline nounwind uwtable
+define i32 @main() {
+entry:
+  %retval = alloca i32, align 4
+  store i32 0, i32* %retval, align 4
+  %call = call i32 (...) @b()
+  ret i32 %call
+}
+
+declare i32 @b(...)