Merge pull request swiftlang#34832 from xymus/rmodule-loading

[Frontend] Intro flag to remark on loaded modules location

Author: xymus

include/swift/AST/DiagnosticsSema.def

@@ -908,6 +908,10 @@ REMARK(cross_import_added,none,
        "import of %0 and %1 triggered a cross-import of %2",
        (Identifier, Identifier, Identifier))
 
+REMARK(module_loaded,none,
+       "loaded module at %0",
+       (StringRef))
+
 // Operator decls
 ERROR(ambiguous_operator_decls,none,
       "ambiguous operator declarations found for operator", ())

include/swift/Basic/LangOptions.h

@@ -129,6 +129,9 @@ namespace swift {
     /// overlay.
     bool EnableCrossImportRemarks = false;
 
+    /// Emit a remark after loading a module.
+    bool EnableModuleLoadingRemarks = false;
+
     ///
     /// Support for alternate usage modes
     ///

include/swift/Option/Options.td

@@ -336,6 +336,10 @@ def emit_cross_import_remarks : Flag<["-"], "Rcross-import">,
   Flags<[FrontendOption, DoesNotAffectIncrementalBuild]>,
   HelpText<"Emit a remark if a cross-import of a module is triggered.">;
 
+def remark_loading_module : Flag<["-"], "Rmodule-loading">,
+  Flags<[FrontendOption, DoesNotAffectIncrementalBuild]>,
+  HelpText<"Emit a remark and file path of each loaded module">;
+
 def emit_tbd : Flag<["-"], "emit-tbd">,
   HelpText<"Emit a TBD file">,
   Flags<[FrontendOption, NoInteractiveOption, SupplementaryOutput]>;

lib/AST/ASTContext.cpp

@@ -1921,6 +1921,11 @@ ASTContext::getModule(ImportPath::Module ModulePath) {
   auto moduleID = ModulePath[0];
   for (auto &importer : getImpl().ModuleLoaders) {
     if (ModuleDecl *M = importer->loadModule(moduleID.Loc, ModulePath)) {
+      if (LangOpts.EnableModuleLoadingRemarks) {
+        Diags.diagnose(ModulePath.getSourceRange().Start,
+                       diag::module_loaded,
+                       M->getModuleFilename());
+      }
       return M;
     }
   }

lib/Frontend/CompilerInvocation.cpp

@@ -577,6 +577,8 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
 
   Opts.EnableCrossImportRemarks = Args.hasArg(OPT_emit_cross_import_remarks);
 
+  Opts.EnableModuleLoadingRemarks = Args.hasArg(OPT_remark_loading_module);
+
   llvm::Triple Target = Opts.Target;
   StringRef TargetArg;
   std::string TargetArgScratch;

test/ModuleInterface/loading-remarks.swift

@@ -0,0 +1,14 @@
+/// Test the -Rmodule-loading flag.
+// RUN: %empty-directory(%t)
+
+/// Create a simple module and interface.
+// RUN: echo 'public func publicFunction() {}' > %t/TestModule.swift
+// RUN: %target-swift-frontend -typecheck %t/TestModule.swift -emit-module-interface-path %t/TestModule.swiftinterface -swift-version 5
+
+/// Use -Rmodule-loading in a client and look for the diagnostics output.
+// RUN: %target-swift-frontend -typecheck %s -I %t -Rmodule-loading 2>&1 | %FileCheck %s
+
+import TestModule
+// CHECK: remark: loaded module at {{.*}}SwiftShims-{{.*}}.pcm
+// CHECK: remark: loaded module at {{.*}}Swift.swiftmodule{{.*}}.swiftmodule
+// CHECK: remark: loaded module at {{.*}}TestModule.swiftinterface