[clang][deps] Track VFS overlay files in file dependencies.

[vsapsai]

rdar://164612831

[llvmbot]

@llvm/pr-subscribers-clang

Author: Volodymyr Sapsai (vsapsai)

Changes

rdar://164612831

---

Full diff: https://github.com/llvm/llvm-project/pull/167824.diff

2 Files Affected:

• (modified) clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp (+4)
• (modified) clang/test/ClangScanDeps/modules-header-sharing.m (+2-1)

diff --git a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
index 0022597348a82..56a364545cd2a 100644
--- a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
+++ b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
@@ -616,6 +616,10 @@ void ModuleDepCollectorPP::EndOfMainFile() {
   if (!MDC.ScanInstance.getPreprocessorOpts().ImplicitPCHInclude.empty())
     MDC.addFileDep(MDC.ScanInstance.getPreprocessorOpts().ImplicitPCHInclude);
 
+  for (const std::string &Overlay :
+       MDC.ScanInstance.getHeaderSearchOpts().VFSOverlayFiles)
+    MDC.addFileDep(Overlay);
+
   for (const Module *M :
        MDC.ScanInstance.getPreprocessor().getAffectingClangModules())
     if (!MDC.isPrebuiltModule(M))
diff --git a/clang/test/ClangScanDeps/modules-header-sharing.m b/clang/test/ClangScanDeps/modules-header-sharing.m
index 31ef351ec38b7..9bba435188721 100644
--- a/clang/test/ClangScanDeps/modules-header-sharing.m
+++ b/clang/test/ClangScanDeps/modules-header-sharing.m
@@ -79,7 +79,8 @@
 // CHECK:                ],
 // CHECK:                "file-deps": [
 // CHECK-NEXT:             "[[PREFIX]]/tu.m",
-// CHECK-NEXT:             "[[PREFIX]]/shared/H.h"
+// CHECK-NEXT:             "[[PREFIX]]/shared/H.h",
+// CHECK-NEXT:             "[[PREFIX]]/overlay.json"
 // CHECK-NEXT:           ],
 // CHECK-NEXT:           "input-file": "[[PREFIX]]/tu.m"
 // CHECK-NEXT:         }

[vsapsai]

Don't have a strong opinion on where tracking VFS files should be done. Mostly was trying to do that after ModuleDepCollectorPP::handleTopLevelModule prunes VFSOverlayFiles in optimizeHeaderSearchOpts.

[jansvoboda11]

LGTM!