Revert "[Dependency Scanning] Use VFS-remapped paths for Clang Module Dependencies' .modulemap files"

include/swift/AST/DiagnosticsSema.def

@@ -2178,7 +2178,6 @@ NOTE(dependency_as_imported_by_main_module,none,
 NOTE(dependency_as_imported_by, none,
      "a dependency of %select{Swift|Clang}2 module '%0': '%1'", (StringRef, StringRef, bool))
 ERROR(clang_dependency_scan_error, none, "Clang dependency scanner failure: %0", (StringRef))
-WARNING(clang_dependency_no_modulemap_fileref, none, "Unable to verify Clang dependency module map '%0': $1", (StringRef, StringRef))
 
 // Enum annotations
 ERROR(indirect_case_without_payload,none,

lib/ClangImporter/ClangModuleDependencyScanner.cpp

@@ -25,7 +25,6 @@
 #include "clang/Tooling/DependencyScanning/DependencyScanningTool.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/Support/Allocator.h"
-#include "llvm/Support/Error.h"
 #include "llvm/Support/FileSystem.h"
 #include "llvm/Support/Signals.h"
 #include "llvm/Support/Path.h"
@@ -266,34 +265,17 @@ ModuleDependencyVector ClangImporter::bridgeClangModuleDependencies(
       swiftArgs.push_back(IncludeTree);
     }
 
-    // Ensure we get the external path to the modulemap because it is used as an
-    // explicit input for the resulting compilation task.
-    auto moduleMapFile =
-        getClangInstance().getFileManager().getFileRef(
-            clangModuleDep.ClangModuleMapFile);
-    StringRef externalModuleMapPath;
-    if (auto E = moduleMapFile.takeError()) {
-      ctx.Diags.diagnose(SourceLoc(),
-                         diag::clang_dependency_no_modulemap_fileref,
-                         clangModuleDep.ClangModuleMapFile,
-                         llvm::toString(std::move(E)));
-      externalModuleMapPath = clangModuleDep.ClangModuleMapFile;
-    } else
-      externalModuleMapPath = moduleMapFile.get().getName();
-
     // Module-level dependencies.
     llvm::StringSet<> alreadyAddedModules;
     auto dependencies = ModuleDependencyInfo::forClangModule(
-        pcmPath, externalModuleMapPath.str(), clangModuleDep.ID.ContextHash,
-        swiftArgs, fileDeps, capturedPCMArgs, RootID, IncludeTree,
-        /*module-cache-key*/ "");
+        pcmPath, clangModuleDep.ClangModuleMapFile,
+        clangModuleDep.ID.ContextHash, swiftArgs, fileDeps, capturedPCMArgs,
+        RootID, IncludeTree, /*module-cache-key*/ "");
     for (const auto &moduleName : clangModuleDep.ClangModuleDeps) {
       dependencies.addModuleImport(moduleName.ModuleName, &alreadyAddedModules);
-      // It is safe to assume that all dependencies of a Clang module are Clang
-      // modules. Doing this allows us to skip "resolving" Clang modules down
-      // the line.
-      dependencies.addModuleDependency(
-          {moduleName.ModuleName, ModuleDependencyKind::Clang});
+      // It is safe to assume that all dependencies of a Clang module are Clang modules.
+      // Doing this allows us to skip "resolving" Clang modules down the line.
+      dependencies.addModuleDependency({moduleName.ModuleName, ModuleDependencyKind::Clang});
     }
     dependencies.setIsResolved(true);