Merge pull request #70769 from artemcm/RemapClangDepModuleMapPath

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

Author: artemcm

include/swift/AST/DiagnosticsSema.def

@@ -2178,6 +2178,7 @@ 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

@@ -25,6 +25,7 @@
 #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"
@@ -265,17 +266,34 @@ 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, clangModuleDep.ClangModuleMapFile,
-        clangModuleDep.ID.ContextHash, swiftArgs, fileDeps, capturedPCMArgs,
-        RootID, IncludeTree, /*module-cache-key*/ "");
+        pcmPath, externalModuleMapPath.str(), 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);
 

test/ScanDependencies/modulemap_vfs_remap.swift

@@ -0,0 +1,50 @@
+// RUN: %empty-directory(%t)
+// RUN: %empty-directory(%t/module-cache)
+// RUN: %empty-directory(%t/inputs)
+// RUN: %empty-directory(%t/remapped)
+
+// RUN: split-file %s %t
+// RUN: sed -e "s|TMPDIR|%/t|g" %t/vfs.json.template > %t/inputs/vfs.json
+
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/module-cache %t/test.swift -o %t/deps.json -I %/t/inputs -Xcc -ivfsoverlay -Xcc %/t/inputs/vfs.json -vfsoverlay %/t/inputs/vfs.json
+// RUN: %validate-json %t/deps.json | %FileCheck %s
+
+//--- remapped/X.h
+void funcX(void);
+
+//--- remapped/RedirectedX.modulemap
+module RedirectedX {
+  header "X.h"
+  export *
+}
+
+//--- vfs.json.template
+{
+  "case-sensitive": false,
+  "version": 0,
+  "roots": [
+    {
+      "type": "directory",
+      "name": "TMPDIR/inputs",
+      "contents": [
+        {
+          "type": "file",
+          "name": "module.modulemap",
+          "external-contents": "TMPDIR/remapped/RedirectedX.modulemap",
+        },
+        {
+          "type": "file",
+          "name": "X.h",
+          "external-contents": "TMPDIR/remapped/X.h",
+        }
+      ]
+    }
+  ]
+}
+
+//--- test.swift
+import RedirectedX
+
+// CHECK: "clang": "RedirectedX"
+// CHECK: "clang": "RedirectedX"
+// CHECK:   "moduleMapPath": "{{.*}}{{/|\\}}remapped{{/|\\}}RedirectedX.modulemap",