Share logic to load dynamic libraries between SourceKit plugins and macro plugins

lib/Basic/LoadDynamicLibrary.cpp

@@ -0,0 +1,57 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2025 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/Basic/LoadDynamicLibrary.h"
+
+#if defined(_WIN32)
+#define WIN32_LEAN_AND_MEAN
+#define NOMINMAX
+#include "llvm/Support/ConvertUTF.h"
+#include "llvm/Support/Windows/WindowsSupport.h"
+#include <windows.h>
+#else
+#include <dlfcn.h>
+#endif
+
+#if defined(_WIN32)
+void *swift::loadLibrary(const char *path, std::string *err) {
+  SmallVector<wchar_t, MAX_PATH> pathUnicode;
+  if (std::error_code ec = llvm::sys::windows::UTF8ToUTF16(path, pathUnicode)) {
+    SetLastError(ec.value());
+    llvm::MakeErrMsg(err, std::string(path) + ": Can't convert to UTF-16");
+    return nullptr;
+  }
+
+  HMODULE handle = LoadLibraryW(pathUnicode.data());
+  if (handle == NULL) {
+    llvm::MakeErrMsg(err, std::string(path) + ": Can't open");
+    return nullptr;
+  }
+  return (void *)handle;
+}
+
+void *swift::getAddressOfSymbol(void *handle, const char *symbol) {
+  return (void *)uintptr_t(GetProcAddress((HMODULE)handle, symbol));
+}
+
+#else
+void *swift::loadLibrary(const char *path, std::string *err) {
+  void *handle = ::dlopen(path, RTLD_LAZY | RTLD_LOCAL);
+  if (!handle)
+    *err = ::dlerror();
+  return handle;
+}
+
+void *swift::getAddressOfSymbol(void *handle, const char *symbol) {
+  return ::dlsym(handle, symbol);
+}
+#endif