2 files changed, 13 insertions, 27 deletions

diff --git a/llvm/lib/ExecutionEngine/RuntimeDyld/RTDyldMemoryManager.cpp b/llvm/lib/ExecutionEngine/RuntimeDyld/RTDyldMemoryManager.cpp
index a9f8ab7bb88..e39acc7ee14 100644
--- a/llvm/lib/ExecutionEngine/RuntimeDyld/RTDyldMemoryManager.cpp
+++ b/llvm/lib/ExecutionEngine/RuntimeDyld/RTDyldMemoryManager.cpp
@@ -262,18 +262,15 @@ RTDyldMemoryManager::getSymbolAddressInProcess(const std::string &Name) {
   // is called before ExecutionEngine::runFunctionAsMain() is called.
   if (Name == "__main") return (uint64_t)&jit_noop;
 
-  // Try to demangle Name before looking it up in the process, otherwise symbol
-  // '_<Name>' (if present) will shadow '<Name>', and there will be no way to
-  // refer to the latter.
-
   const char *NameStr = Name.c_str();
 
+  // DynamicLibrary::SearchForAddresOfSymbol expects an unmangled 'C' symbol
+  // name so ff we're on Darwin, strip the leading '_' off.
+#ifdef __APPLE__
   if (NameStr[0] == '_')
-    if (void *Ptr = sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr + 1))
-      return (uint64_t)Ptr;
+    ++NameStr;
+#endif
 
-  // If we Name did not require demangling, or we failed to find the demangled
-  // name, try again without demangling.
   return (uint64_t)sys::DynamicLibrary::SearchForAddressOfSymbol(NameStr);
 }
 
@@ -284,6 +281,7 @@ void *RTDyldMemoryManager::getPointerToNamedFunction(const std::string &Name,
   if (!Addr && AbortOnFailure)
     report_fatal_error("Program used external function '" + Name +
                        "' which could not be resolved!");
+
   return (void*)Addr;
 }
 
diff --git a/llvm/unittests/ExecutionEngine/ExecutionEngineTest.cpp b/llvm/unittests/ExecutionEngine/ExecutionEngineTest.cpp
index bb47c4c0030..3ffa9cd9b8f 100644
--- a/llvm/unittests/ExecutionEngine/ExecutionEngineTest.cpp
+++ b/llvm/unittests/ExecutionEngine/ExecutionEngineTest.cpp
@@ -136,35 +136,23 @@ TEST_F(ExecutionEngineTest, DestructionRemovesGlobalMapping) {
   EXPECT_EQ(nullptr, Engine->getGlobalValueAtAddress(&Mem1));
 }
 
-TEST_F(ExecutionEngineTest, LookupWithMangledName) {
-  int x;
-  llvm::sys::DynamicLibrary::AddSymbol("x", &x);
-
-  // Demonstrate that getSymbolAddress accepts mangled names and always strips
-  // the leading underscore.
-  EXPECT_EQ(reinterpret_cast<uint64_t>(&x),
-            RTDyldMemoryManager::getSymbolAddressInProcess("_x"));
-}
-
 TEST_F(ExecutionEngineTest, LookupWithMangledAndDemangledSymbol) {
   int x;
   int _x;
   llvm::sys::DynamicLibrary::AddSymbol("x", &x);
   llvm::sys::DynamicLibrary::AddSymbol("_x", &_x);
 
-  // Lookup the demangled name first, even if there's a demangled symbol that
-  // matches the input already.
+  // RTDyldMemoryManager::getSymbolAddressInProcess expects a mangled symbol,
+  // but DynamicLibrary is a wrapper for dlsym, which expects the unmangled C
+  // symbol name. This test verifies that getSymbolAddressInProcess strips the
+  // leading '_' on Darwin, but not on other platforms.
+#ifdef __APPLE__
   EXPECT_EQ(reinterpret_cast<uint64_t>(&x),
             RTDyldMemoryManager::getSymbolAddressInProcess("_x"));
-}
-
-TEST_F(ExecutionEngineTest, LookupwithDemangledName) {
-  int _x;
-  llvm::sys::DynamicLibrary::AddSymbol("_x", &_x);
-
-  // But do fallback to looking up a demangled name if there's no ambiguity
+#else
   EXPECT_EQ(reinterpret_cast<uint64_t>(&_x),
             RTDyldMemoryManager::getSymbolAddressInProcess("_x"));
+#endif
 }
 
 }