Merge pull request #3780 from adrian-prantl/null-swiftastcontext56

Fix nullptr deref and reenable test

Author: adrian-prantl

lldb/source/Plugins/TypeSystem/Swift/SwiftASTContext.cpp

@@ -3271,6 +3271,8 @@ class SwiftDWARFImporterDelegate : public swift::DWARFImporterDelegate {
       for (size_t i = 0; i != images.GetSize(); ++i) {
         auto module_sp = images.GetModuleAtIndex(i);
         auto *swift_ast_ctx = GetModuleSwiftASTContext(*module_sp);
+	if (!swift_ast_ctx)
+          continue;
         auto *dwarf_imp = static_cast<SwiftDWARFImporterDelegate *>(
             swift_ast_ctx->GetDWARFImporterDelegate());
         if (!dwarf_imp || dwarf_imp == this)

lldb/test/API/lang/swift/implementation_only_imports/library_indirect/TestLibraryIndirect.py

@@ -78,7 +78,6 @@ def cleanup():
         self.expect("e container.wrapped.value", substrs=["(SomeLibraryCore.TwoInts)", "(first = 2, second = 3)"])
 
     @swiftTest
-    @skipIfLinux # The "e container" command crashes in a non-reproducible way on the Linux bots.
     def test_implementation_only_import_library_no_library_module(self):
         """Test `@_implementationOnly import` behind some indirection in a library used by the main executable, after removing the implementation-only library's swiftmodule
 

lldb/test/API/lang/swift/implementation_only_imports/library_resilient/TestLibraryResilient.py

@@ -65,7 +65,6 @@ def cleanup():
 
     @swiftTest
     @expectedFailureAll(oslist=["windows"]) # Requires Remote Mirrors support
-    @skipIfLinux # The "e container" command crashes in a non-reproducible way on the Linux bots.
     def test_implementation_only_import_library_no_library_module(self):
         """Test `@_implementationOnly import` in a resilient library used by the main executable, after removing the implementation-only library's swiftmodule