[lldb] Extract FileSystem initialization code into helper (NFC)

The FileSystem initialization depends on the reproducer mode. It has
been growing organically to the point where it deserves its own helper
function. This also allows for early returns to simplify the code.

Author: JDevlieghere

lldb/source/Initialization/SystemInitializerCommon.cpp

@@ -39,6 +39,51 @@ SystemInitializerCommon::SystemInitializerCommon() {}
 
 SystemInitializerCommon::~SystemInitializerCommon() {}
 
+/// Initialize the FileSystem based on the current reproducer mode.
+static llvm::Error InitializeFileSystem() {
+  auto &r = repro::Reproducer::Instance();
+  if (repro::Loader *loader = r.GetLoader()) {
+    FileSpec vfs_mapping = loader->GetFile<FileProvider::Info>();
+    if (vfs_mapping) {
+      if (llvm::Error e = FileSystem::Initialize(vfs_mapping))
+        return e;
+    } else {
+      FileSystem::Initialize();
+    }
+
+    llvm::Expected<std::string> cwd =
+        loader->LoadBuffer<WorkingDirectoryProvider>();
+    if (!cwd)
+      return cwd.takeError();
+
+    llvm::StringRef working_dir = llvm::StringRef(*cwd).rtrim();
+    if (std::error_code ec = FileSystem::Instance()
+                                 .GetVirtualFileSystem()
+                                 ->setCurrentWorkingDirectory(working_dir)) {
+      return llvm::errorCodeToError(ec);
+    }
+
+    return llvm::Error::success();
+  }
+
+  if (repro::Generator *g = r.GetGenerator()) {
+    repro::VersionProvider &vp = g->GetOrCreate<repro::VersionProvider>();
+    vp.SetVersion(lldb_private::GetVersion());
+
+    repro::FileProvider &fp = g->GetOrCreate<repro::FileProvider>();
+    FileSystem::Initialize(fp.GetFileCollector());
+
+    repro::WorkingDirectoryProvider &wp =
+        g->GetOrCreate<repro::WorkingDirectoryProvider>();
+    fp.RecordInterestingDirectory(wp.GetWorkingDirectory());
+
+    return llvm::Error::success();
+  }
+
+  FileSystem::Initialize();
+  return llvm::Error::success();
+}
+
 llvm::Error SystemInitializerCommon::Initialize() {
 #if defined(_WIN32)
   const char *disable_crash_dialog_var = getenv("LLDB_DISABLE_CRASH_DIALOG");
@@ -69,36 +114,8 @@ llvm::Error SystemInitializerCommon::Initialize() {
       return e;
   }
 
-  auto &r = repro::Reproducer::Instance();
-  if (repro::Loader *loader = r.GetLoader()) {
-    FileSpec vfs_mapping = loader->GetFile<FileProvider::Info>();
-    if (vfs_mapping) {
-      if (llvm::Error e = FileSystem::Initialize(vfs_mapping))
-        return e;
-    } else {
-      FileSystem::Initialize();
-    }
-    if (llvm::Expected<std::string> cwd =
-            loader->LoadBuffer<WorkingDirectoryProvider>()) {
-      llvm::StringRef working_dir = llvm::StringRef(*cwd).rtrim();
-      if (std::error_code ec = FileSystem::Instance()
-                                   .GetVirtualFileSystem()
-                                   ->setCurrentWorkingDirectory(working_dir)) {
-        return llvm::errorCodeToError(ec);
-      }
-    } else {
-      return cwd.takeError();
-    }
-  } else if (repro::Generator *g = r.GetGenerator()) {
-    repro::VersionProvider &vp = g->GetOrCreate<repro::VersionProvider>();
-    vp.SetVersion(lldb_private::GetVersion());
-    repro::FileProvider &fp = g->GetOrCreate<repro::FileProvider>();
-    FileSystem::Initialize(fp.GetFileCollector());
-    repro::WorkingDirectoryProvider &wp = g->GetOrCreate<repro::WorkingDirectoryProvider>();
-    fp.RecordInterestingDirectory(wp.GetWorkingDirectory());
-  } else {
-    FileSystem::Initialize();
-  }
+  if (auto e = InitializeFileSystem())
+    return e;
 
   Log::Initialize();
   HostInfo::Initialize();