Index: clang/lib/Interpreter/IncrementalExecutor.cpp
===================================================================
--- clang/lib/Interpreter/IncrementalExecutor.cpp
+++ clang/lib/Interpreter/IncrementalExecutor.cpp
@@ -45,8 +45,11 @@
   }
 
   const char Pref = Jit->getDataLayout().getGlobalPrefix();
+  const bool DoNotMangleLeadingQuestionMark =
+      Jit->getDataLayout().doNotMangleLeadingQuestionMark();
   // Discover symbols from the process as a fallback.
-  if (auto PSGOrErr = DynamicLibrarySearchGenerator::GetForCurrentProcess(Pref))
+  if (auto PSGOrErr = DynamicLibrarySearchGenerator::GetForCurrentProcess(
+          Pref, DoNotMangleLeadingQuestionMark))
     Jit->getMainJITDylib().addGenerator(std::move(*PSGOrErr));
   else {
     Err = PSGOrErr.takeError();
Index: llvm/docs/ORCv2.rst
===================================================================
--- llvm/docs/ORCv2.rst
+++ llvm/docs/ORCv2.rst
@@ -870,7 +870,7 @@
     // Use GetForCurrentProcess with a predicate function that checks the
     // allowed list.
     JD.addGenerator(cantFail(DynamicLibrarySearchGenerator::GetForCurrentProcess(
-          DL.getGlobalPrefix(),
+          DL.getGlobalPrefix(), DL.doNotMangleLeadingQuestionMark(),
           [&](const SymbolStringPtr &S) { return AllowList.count(S); })));
 
     // IR added to JD can now link against any symbols exported by the process
Index: llvm/docs/tutorial/BuildingAJIT1.rst
===================================================================
--- llvm/docs/tutorial/BuildingAJIT1.rst
+++ llvm/docs/tutorial/BuildingAJIT1.rst
@@ -143,7 +143,8 @@
           DL(std::move(DL)), Mangle(ES, this->DL),
           Ctx(std::make_unique<LLVMContext>()) {
       ES.getMainJITDylib().addGenerator(
-          cantFail(DynamicLibrarySearchGenerator::GetForCurrentProcess(DL.getGlobalPrefix())));
+          cantFail(DynamicLibrarySearchGenerator::GetForCurrentProcess(
+              DL.getGlobalPrefix(), DL.doNotMangleLeadingQuestionMark())));
     }
 
 Our class begins with six member variables: An ExecutionSession member, ``ES``,
Index: llvm/docs/tutorial/BuildingAJIT2.rst
===================================================================
--- llvm/docs/tutorial/BuildingAJIT2.rst
+++ llvm/docs/tutorial/BuildingAJIT2.rst
@@ -77,7 +77,8 @@
           DL(std::move(DL)), Mangle(ES, this->DL),
           Ctx(std::make_unique<LLVMContext>()) {
       ES.getMainJITDylib().addGenerator(
-          cantFail(DynamicLibrarySearchGenerator::GetForCurrentProcess(DL.getGlobalPrefix())));
+          cantFail(DynamicLibrarySearchGenerator::GetForCurrentProcess(
+              DL.getGlobalPrefix(), DL.doNotMangleLeadingQuestionMark())));
     }
 
 Our extended KaleidoscopeJIT class starts out the same as it did in Chapter 1,
Index: llvm/examples/Kaleidoscope/BuildingAJIT/Chapter1/KaleidoscopeJIT.h
===================================================================
--- llvm/examples/Kaleidoscope/BuildingAJIT/Chapter1/KaleidoscopeJIT.h
+++ llvm/examples/Kaleidoscope/BuildingAJIT/Chapter1/KaleidoscopeJIT.h
@@ -53,7 +53,7 @@
         MainJD(this->ES->createBareJITDylib("<main>")) {
     MainJD.addGenerator(
         cantFail(DynamicLibrarySearchGenerator::GetForCurrentProcess(
-            DL.getGlobalPrefix())));
+            DL.getGlobalPrefix(), DL.doNotMangleLeadingQuestionMark())));
   }
 
   ~KaleidoscopeJIT() {
Index: llvm/examples/Kaleidoscope/BuildingAJIT/Chapter2/KaleidoscopeJIT.h
===================================================================
--- llvm/examples/Kaleidoscope/BuildingAJIT/Chapter2/KaleidoscopeJIT.h
+++ llvm/examples/Kaleidoscope/BuildingAJIT/Chapter2/KaleidoscopeJIT.h
@@ -60,7 +60,7 @@
         MainJD(this->ES->createBareJITDylib("<main>")) {
     MainJD.addGenerator(
         cantFail(DynamicLibrarySearchGenerator::GetForCurrentProcess(
-            DL.getGlobalPrefix())));
+            DL.getGlobalPrefix(), DL.doNotMangleLeadingQuestionMark())));
   }
 
   ~KaleidoscopeJIT() {
Index: llvm/examples/Kaleidoscope/BuildingAJIT/Chapter3/KaleidoscopeJIT.h
===================================================================
--- llvm/examples/Kaleidoscope/BuildingAJIT/Chapter3/KaleidoscopeJIT.h
+++ llvm/examples/Kaleidoscope/BuildingAJIT/Chapter3/KaleidoscopeJIT.h
@@ -74,7 +74,7 @@
         MainJD(this->ES->createBareJITDylib("<main>")) {
     MainJD.addGenerator(
         cantFail(DynamicLibrarySearchGenerator::GetForCurrentProcess(
-            DL.getGlobalPrefix())));
+            DL.getGlobalPrefix(), DL.doNotMangleLeadingQuestionMark())));
   }
 
   ~KaleidoscopeJIT() {
Index: llvm/examples/Kaleidoscope/BuildingAJIT/Chapter4/KaleidoscopeJIT.h
===================================================================
--- llvm/examples/Kaleidoscope/BuildingAJIT/Chapter4/KaleidoscopeJIT.h
+++ llvm/examples/Kaleidoscope/BuildingAJIT/Chapter4/KaleidoscopeJIT.h
@@ -159,7 +159,7 @@
         MainJD(this->ES->createBareJITDylib("<main>")) {
     MainJD.addGenerator(
         cantFail(DynamicLibrarySearchGenerator::GetForCurrentProcess(
-            DL.getGlobalPrefix())));
+            DL.getGlobalPrefix(), DL.doNotMangleLeadingQuestionMark())));
   }
 
   ~KaleidoscopeJIT() {
Index: llvm/examples/Kaleidoscope/include/KaleidoscopeJIT.h
===================================================================
--- llvm/examples/Kaleidoscope/include/KaleidoscopeJIT.h
+++ llvm/examples/Kaleidoscope/include/KaleidoscopeJIT.h
@@ -53,7 +53,7 @@
         MainJD(this->ES->createBareJITDylib("<main>")) {
     MainJD.addGenerator(
         cantFail(DynamicLibrarySearchGenerator::GetForCurrentProcess(
-            DL.getGlobalPrefix())));
+            DL.getGlobalPrefix(), DL.doNotMangleLeadingQuestionMark())));
     if (JTMB.getTargetTriple().isOSBinFormatCOFF()) {
       ObjectLayer.setOverrideObjectFlagsWithResponsibilityFlags(true);
       ObjectLayer.setAutoClaimResponsibilityForObjectSymbols(true);
Index: llvm/examples/OrcV2Examples/LLJITWithGDBRegistrationListener/LLJITWithGDBRegistrationListener.cpp
===================================================================
--- llvm/examples/OrcV2Examples/LLJITWithGDBRegistrationListener/LLJITWithGDBRegistrationListener.cpp
+++ llvm/examples/OrcV2Examples/LLJITWithGDBRegistrationListener/LLJITWithGDBRegistrationListener.cpp
@@ -88,6 +88,7 @@
     J->getMainJITDylib().addGenerator(
         ExitOnErr(orc::DynamicLibrarySearchGenerator::GetForCurrentProcess(
             J->getDataLayout().getGlobalPrefix(),
+            J->getDataLayout().doNotMangleLeadingQuestionMark(),
             [MainName = Mangle("main")](const orc::SymbolStringPtr &Name) {
               return Name != MainName;
             })));
Index: llvm/examples/OrcV2Examples/LLJITWithObjectLinkingLayerPlugin/LLJITWithObjectLinkingLayerPlugin.cpp
===================================================================
--- llvm/examples/OrcV2Examples/LLJITWithObjectLinkingLayerPlugin/LLJITWithObjectLinkingLayerPlugin.cpp
+++ llvm/examples/OrcV2Examples/LLJITWithObjectLinkingLayerPlugin/LLJITWithObjectLinkingLayerPlugin.cpp
@@ -223,7 +223,8 @@
     // objects can do interesting things, like call printf.
     J->getMainJITDylib().addGenerator(
         ExitOnErr(DynamicLibrarySearchGenerator::GetForCurrentProcess(
-            J->getDataLayout().getGlobalPrefix())));
+            J->getDataLayout().getGlobalPrefix(),
+            J->getDataLayout().doNotMangleLeadingQuestionMark())));
 
     // Load the input objects.
     for (auto InputObject : InputObjects) {
Index: llvm/examples/SpeculativeJIT/SpeculativeJIT.cpp
===================================================================
--- llvm/examples/SpeculativeJIT/SpeculativeJIT.cpp
+++ llvm/examples/SpeculativeJIT/SpeculativeJIT.cpp
@@ -69,7 +69,7 @@
 
     auto ProcessSymbolsSearchGenerator =
         DynamicLibrarySearchGenerator::GetForCurrentProcess(
-            DL->getGlobalPrefix());
+            DL->getGlobalPrefix(), DL->doNotMangleLeadingQuestionMark());
     if (!ProcessSymbolsSearchGenerator)
       return ProcessSymbolsSearchGenerator.takeError();
 
Index: llvm/include/llvm/ExecutionEngine/Orc/ExecutionUtils.h
===================================================================
--- llvm/include/llvm/ExecutionEngine/Orc/ExecutionUtils.h
+++ llvm/include/llvm/ExecutionEngine/Orc/ExecutionUtils.h
@@ -225,6 +225,7 @@
   /// will be searched for. If the predicate is not given then all symbols will
   /// be searched for.
   DynamicLibrarySearchGenerator(sys::DynamicLibrary Dylib, char GlobalPrefix,
+                                bool DoNotMangleLeadingQuestionMark = false,
                                 SymbolPredicate Allow = SymbolPredicate());
 
   /// Permanently loads the library at the given path and, on success, returns
@@ -232,14 +233,17 @@
   /// in the library. On failure returns the reason the library failed to load.
   static Expected<std::unique_ptr<DynamicLibrarySearchGenerator>>
   Load(const char *FileName, char GlobalPrefix,
+       bool DoNotMangleLeadingQuestionMark = false,
        SymbolPredicate Allow = SymbolPredicate());
 
   /// Creates a DynamicLibrarySearchGenerator that searches for symbols in
   /// the current process.
   static Expected<std::unique_ptr<DynamicLibrarySearchGenerator>>
   GetForCurrentProcess(char GlobalPrefix,
+                       bool DoNotMangleLeadingQuestionMark = false,
                        SymbolPredicate Allow = SymbolPredicate()) {
-    return Load(nullptr, GlobalPrefix, std::move(Allow));
+    return Load(nullptr, GlobalPrefix, DoNotMangleLeadingQuestionMark,
+                std::move(Allow));
   }
 
   Error tryToGenerate(LookupState &LS, LookupKind K, JITDylib &JD,
@@ -250,6 +254,7 @@
   sys::DynamicLibrary Dylib;
   SymbolPredicate Allow;
   char GlobalPrefix;
+  bool DoNotMangleLeadingQuestionMark;
 };
 
 /// A utility class to expose symbols from a static library.
Index: llvm/lib/ExecutionEngine/Orc/ExecutionUtils.cpp
===================================================================
--- llvm/lib/ExecutionEngine/Orc/ExecutionUtils.cpp
+++ llvm/lib/ExecutionEngine/Orc/ExecutionUtils.cpp
@@ -221,19 +221,23 @@
 }
 
 DynamicLibrarySearchGenerator::DynamicLibrarySearchGenerator(
-    sys::DynamicLibrary Dylib, char GlobalPrefix, SymbolPredicate Allow)
+    sys::DynamicLibrary Dylib, char GlobalPrefix,
+    bool DoNotMangleLeadingQuestionMark, SymbolPredicate Allow)
     : Dylib(std::move(Dylib)), Allow(std::move(Allow)),
-      GlobalPrefix(GlobalPrefix) {}
+      GlobalPrefix(GlobalPrefix),
+      DoNotMangleLeadingQuestionMark(DoNotMangleLeadingQuestionMark) {}
 
 Expected<std::unique_ptr<DynamicLibrarySearchGenerator>>
 DynamicLibrarySearchGenerator::Load(const char *FileName, char GlobalPrefix,
+                                    bool DoNotMangleLeadingQuestionMark,
                                     SymbolPredicate Allow) {
   std::string ErrMsg;
   auto Lib = sys::DynamicLibrary::getPermanentLibrary(FileName, &ErrMsg);
   if (!Lib.isValid())
     return make_error<StringError>(std::move(ErrMsg), inconvertibleErrorCode());
   return std::make_unique<DynamicLibrarySearchGenerator>(
-      std::move(Lib), GlobalPrefix, std::move(Allow));
+      std::move(Lib), GlobalPrefix, DoNotMangleLeadingQuestionMark,
+      std::move(Allow));
 }
 
 Error DynamicLibrarySearchGenerator::tryToGenerate(
@@ -252,11 +256,19 @@
     if (Allow && !Allow(Name))
       continue;
 
-    if (HasGlobalPrefix && (*Name).front() != GlobalPrefix)
+    bool StripFirstCharacter = HasGlobalPrefix;
+    char FirstCharacter = (*Name).front();
+    if (FirstCharacter == '?' && DoNotMangleLeadingQuestionMark) {
+      // Continue without stripping the first character; it is ok that the
+      // mangled name does not start with GlobalPrefix (if there is one).
+      StripFirstCharacter = false;
+    } else if (HasGlobalPrefix && FirstCharacter != GlobalPrefix) {
+      // The mangled name does not start with GlobalPrefix, skip.
       continue;
+    }
 
-    std::string Tmp((*Name).data() + HasGlobalPrefix,
-                    (*Name).size() - HasGlobalPrefix);
+    std::string Tmp((*Name).data() + StripFirstCharacter,
+                    (*Name).size() - StripFirstCharacter);
     if (void *Addr = Dylib.getAddressOfSymbol(Tmp.c_str())) {
       NewSymbols[Name] = JITEvaluatedSymbol(
           static_cast<JITTargetAddress>(reinterpret_cast<uintptr_t>(Addr)),
Index: llvm/lib/ExecutionEngine/Orc/OrcV2CBindings.cpp
===================================================================
--- llvm/lib/ExecutionEngine/Orc/OrcV2CBindings.cpp
+++ llvm/lib/ExecutionEngine/Orc/OrcV2CBindings.cpp
@@ -690,7 +690,8 @@
 
 LLVMErrorRef LLVMOrcCreateDynamicLibrarySearchGeneratorForProcess(
     LLVMOrcDefinitionGeneratorRef *Result, char GlobalPrefix,
-    LLVMOrcSymbolPredicate Filter, void *FilterCtx) {
+    bool DoNotMangleLeadingQuestionMark, LLVMOrcSymbolPredicate Filter,
+    void *FilterCtx) {
   assert(Result && "Result can not be null");
   assert((Filter || !FilterCtx) &&
          "if Filter is null then FilterCtx must also be null");
@@ -702,7 +703,8 @@
     };
 
   auto ProcessSymsGenerator =
-      DynamicLibrarySearchGenerator::GetForCurrentProcess(GlobalPrefix, Pred);
+      DynamicLibrarySearchGenerator::GetForCurrentProcess(
+          GlobalPrefix, DoNotMangleLeadingQuestionMark, Pred);
 
   if (!ProcessSymsGenerator) {
     *Result = nullptr;
@@ -715,7 +717,8 @@
 
 LLVMErrorRef LLVMOrcCreateDynamicLibrarySearchGeneratorForPath(
     LLVMOrcDefinitionGeneratorRef *Result, const char *FileName,
-    char GlobalPrefix, LLVMOrcSymbolPredicate Filter, void *FilterCtx) {
+    char GlobalPrefix, bool DoNotMangleLeadingQuestionMark,
+    LLVMOrcSymbolPredicate Filter, void *FilterCtx) {
   assert(Result && "Result can not be null");
   assert(FileName && "FileName can not be null");
   assert((Filter || !FilterCtx) &&
@@ -727,8 +730,8 @@
       return Filter(FilterCtx, wrap(OrcV2CAPIHelper::getRawPoolEntryPtr(Name)));
     };
 
-  auto LibrarySymsGenerator =
-      DynamicLibrarySearchGenerator::Load(FileName, GlobalPrefix, Pred);
+  auto LibrarySymsGenerator = DynamicLibrarySearchGenerator::Load(
+      FileName, GlobalPrefix, DoNotMangleLeadingQuestionMark, Pred);
 
   if (!LibrarySymsGenerator) {
     *Result = nullptr;
Index: llvm/tools/lli/lli.cpp
===================================================================
--- llvm/tools/lli/lli.cpp
+++ llvm/tools/lli/lli.cpp
@@ -979,6 +979,7 @@
     J->getMainJITDylib().addGenerator(
         ExitOnErr(orc::DynamicLibrarySearchGenerator::GetForCurrentProcess(
             J->getDataLayout().getGlobalPrefix(),
+            J->getDataLayout().doNotMangleLeadingQuestionMark(),
             [MainName = Mangle("main")](const orc::SymbolStringPtr &Name) {
               return Name != MainName;
             })));
Index: mlir/lib/ExecutionEngine/ExecutionEngine.cpp
===================================================================
--- mlir/lib/ExecutionEngine/ExecutionEngine.cpp
+++ mlir/lib/ExecutionEngine/ExecutionEngine.cpp
@@ -354,7 +354,8 @@
   llvm::orc::JITDylib &mainJD = engine->jit->getMainJITDylib();
   mainJD.addGenerator(
       cantFail(DynamicLibrarySearchGenerator::GetForCurrentProcess(
-          dataLayout.getGlobalPrefix())));
+          dataLayout.getGlobalPrefix(),
+          dataLayout.doNotMangleLeadingQuestionMark())));
 
   return std::move(engine);
 }