[linux] Re-enable parallel testing after avoiding static destructors

Package.swift

@@ -45,9 +45,13 @@ let package = Package(
         ]
       ),
 
+      .target(
+        name: "CSKTestSupport",
+        dependencies: []),
       .target(
         name: "SKTestSupport",
         dependencies: [
+          "CSKTestSupport",
           "ISDBTestSupport",
           "LSPTestSupport",
           "SourceKit",

Sources/CSKTestSupport/CSKTestSupport.c

@@ -0,0 +1,19 @@
+//===----------------------------------------------------------------------===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2020 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
+//
+//===----------------------------------------------------------------------===//
+
+#ifdef __linux__
+// For testing, override __cxa_atexit to prevent registration of static
+// destructors due to SR-12668.
+int __cxa_atexit(void (*f) (void *), void *arg, void *dso_handle) {
+  return 0;
+}
+#endif

Sources/SKSupport/dlopen.swift

@@ -59,12 +59,8 @@ public struct DLOpenFlags: RawRepresentable, OptionSet {
   // Platform-specific flags.
   #if os(macOS)
     public static let first: DLOpenFlags = DLOpenFlags(rawValue: RTLD_FIRST)
-    public static let deepBind: DLOpenFlags = DLOpenFlags(rawValue: 0)
   #else
     public static let first: DLOpenFlags = DLOpenFlags(rawValue: 0)
-  #if !os(Android)
-    public static let deepBind: DLOpenFlags = DLOpenFlags(rawValue: RTLD_DEEPBIND)
-  #endif
   #endif
   #endif
 

Sources/SourceKit/sourcekitd/SwiftSourceKitFramework.swift

@@ -46,10 +46,8 @@ final class SwiftSourceKitFramework {
     self.path = path
     #if os(Windows)
     self.dylib = try dlopen(path.pathString, mode: [])
-    #elseif os(Android)
-    self.dylib = try dlopen(path.pathString, mode: [.lazy, .local, .first])
     #else
-    self.dylib = try dlopen(path.pathString, mode: [.lazy, .local, .first, .deepBind])
+    self.dylib = try dlopen(path.pathString, mode: [.lazy, .local, .first])
     #endif
 
     func dlsym_required<T>(_ handle: DLHandle, symbol: String) throws -> T {

Sources/sourcekit-lsp/main.swift

@@ -121,7 +121,8 @@ let server = SourceKitServer(client: clientConnection, options: options.serverOp
 })
 clientConnection.start(receiveHandler: server, closeHandler: {
   server.prepareForExit()
-  exit(0)
+  // Use _Exit to avoid running static destructors due to SR-12668.
+  _Exit(0)
 })
 
 Logger.shared.addLogHandler { message, _ in

Utilities/build-script-helper.py

@@ -86,6 +86,15 @@ def delete_rpath(rpath, binary):
   subprocess.check_call(cmd)
 
 
+def should_test_parallel():
+  if platform.system() == 'Linux':
+    distro = platform.linux_distribution()
+    if distro[0] != 'Ubuntu':
+      # Workaround hang in Process.run() that hasn't been tracked down yet.
+      return False
+  return True
+
+
 def handle_invocation(swift_exec, args):
   swiftpm_args = get_swiftpm_options(args)
 
@@ -114,7 +123,10 @@ def handle_invocation(swift_exec, args):
     tests = os.path.join(bin_path, 'sk-tests')
     print('Cleaning ' + tests)
     shutil.rmtree(tests, ignore_errors=True)
-    swiftpm('test', swift_exec, swiftpm_args, env)
+    test_args = swiftpm_args
+    if should_test_parallel():
+      test_args += ['--parallel']
+    swiftpm('test', swift_exec, test_args, env)
   elif args.action == 'install':
     bin_path = swiftpm_bin_path(swift_exec, swiftpm_args, env)
     swiftpm('build', swift_exec, swiftpm_args, env)