[lldb] Add Clang module import logging

[kastiglione]

Summary

Log Clang module imports to lldb's expr channel. This is similar to enabling module import remarks in clang with -Rmodule-import.

This is minor add-on to D140056, which logs module _builds_ while also broadcasting Progress events.

[kastiglione]

Add -Rmodule-import flag

[aprantl]

This looks great, and I think this should also be easy to test? I think we have many other tests that write out a logfile and FileCheck the result.

lldb/source/Plugins/ExpressionParser/Clang/ClangModulesDeclVendor.cpp

if (m_module_build_stack.empty()) {
       const auto &resumed_module_name = m_module_build_stack.back();
       SetCurrentModuleProgress(resumed_module_name);
     }
 
     const auto &module_name = info.getArgStdStr(0);
     LLDB_LOG(log, "Finished building Clang module {0}", module_name);
     return true;
   }
+  case clang::diag::remark_module_import: {
+    const auto &module_name = info.getArgStdStr(0);
+    const auto &module_path = info.getArgStdStr(1);
+    LLDB_LOG(log, "Importing Clang module {0} from {1}", module_name,
+             module_path);
+    return true;
+  }
   default:
     return false;
   }
 }
 
 void StoringDiagnosticConsumer::SetCurrentModuleProgress(
     std::string module_name) {
   if (!m_current_progress_up)
std::vector<std::string> compiler_invocation_arguments = {
       "-fcxx-modules",
       "-fsyntax-only",
       "-femit-all-decls",
       "-target",
       arch.GetTriple().str(),
       "-fmodules-validate-system-headers",
       "-Werror=non-modular-include-in-framework-module",
       "-Xclang=-fincremental-extensions",
-      "-Rmodule-build"};
+      "-Rmodule-build",
+      "-Rmodule-import"};
 
   target.GetPlatform()->AddClangModuleCompilationOptions(
       &target, compiler_invocation_arguments);
 
   compiler_invocation_arguments.push_back(ModuleImportBufferName);
 
   // Add additional search paths with { "-I", path } or { "-F", path } here.