[NFC] Split ModuleTrace Infrastructure out of FrontendTool

Author: CodaFi

lib/FrontendTool/CMakeLists.txt

@@ -2,6 +2,7 @@ set_swift_llvm_is_available()
 add_swift_host_library(swiftFrontendTool STATIC
   FrontendTool.cpp
   ImportedModules.cpp
+  LoadedModuleTrace.cpp
   MakeStyleDependencies.cpp
   ScanDependencies.cpp
   TBD.cpp)

lib/FrontendTool/Dependencies.h

@@ -22,10 +22,17 @@ class FrontendOptions;
 class InputFile;
 class ModuleDecl;
 
+/// Emit the names of the modules imported by \c mainModule.
+bool emitImportedModules(ModuleDecl *mainModule, const FrontendOptions &opts);
 bool emitMakeDependenciesIfNeeded(DiagnosticEngine &diags,
                                   DependencyTracker *depTracker,
                                   const FrontendOptions &opts,
                                   const InputFile &input);
+bool emitLoadedModuleTraceIfNeeded(ModuleDecl *mainModule,
+                                   DependencyTracker *depTracker,
+                                   const FrontendOptions &opts,
+                                   const InputFile &input);
+
 } // end namespace swift
 
 #endif