[Clang][ScanDeps] Ignore __inferred_module.map dependency.

This shows up with inferred modules, but it doesn't exist on disk, so
don't report it as a dependency.

Author: Bigcheese

clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp

@@ -155,6 +155,15 @@ void ModuleDepCollectorPP::handleTopLevelModule(const Module *M) {
       MDC.Instance.getASTReader()->getModuleManager().lookup(M->getASTFile());
   MDC.Instance.getASTReader()->visitInputFiles(
       *MF, true, true, [&](const serialization::InputFile &IF, bool isSystem) {
+        // __inferred_module.map is the result of the way in which an implicit
+        // module build handles inferred modules. It adds an overlay VFS with
+        // this file in the proper directory and relies on the rest of Clang to
+        // handle it like normal. With explicitly built modules we don't need
+        // to play VFS tricks, so replace it with the correct module map.
+        if (IF.getFile()->getName().endswith("__inferred_module.map")) {
+          MD.FileDeps.insert(ModuleMap->getName());
+          return;
+        }
         MD.FileDeps.insert(IF.getFile()->getName());
       });
   MD.NonPathCommandLine = {

clang/test/ClangScanDeps/modules-inferred.m

@@ -32,7 +32,7 @@
 // CHECK-NEXT:       "file-deps": [
 // CHECK-NEXT:         "[[SOURCEDIR]]/Inputs/frameworks/Inferred.framework/Frameworks/Sub.framework/Headers/Sub.h",
 // CHECK-NEXT:         "[[SOURCEDIR]]/Inputs/frameworks/Inferred.framework/Headers/Inferred.h",
-// CHECK-NEXT:         "[[SOURCEDIR]]/Inputs/frameworks/Inferred.framework/__inferred_module.map"
+// CHECK-NEXT:         "[[SOURCEDIR]]/Inputs/frameworks/module.modulemap"
 // CHECK-NEXT:       ],
 // CHECK-NEXT:       "name": "Inferred"
 // CHECK-NEXT:     }