diff --git a/clang/include/clang/Tooling/DependencyScanning/ModuleDepCollector.h b/clang/include/clang/Tooling/DependencyScanning/ModuleDepCollector.h
--- a/clang/include/clang/Tooling/DependencyScanning/ModuleDepCollector.h
+++ b/clang/include/clang/Tooling/DependencyScanning/ModuleDepCollector.h
@@ -143,6 +143,10 @@
 
   void handleImport(const Module *Imported);
 
+  /// Adds direct modular dependencies that were prebuilt to the ModuleDeps
+  /// instance as file dependencies.
+  void addDirectPrebuiltModuleDeps(const Module *M, ModuleDeps &MD);
+
   /// Traverses the previously collected direct modular dependencies to discover
   /// transitive modular dependencies and fills the parent \c ModuleDepCollector
   /// with both.
@@ -158,7 +162,8 @@
 class ModuleDepCollector final : public DependencyCollector {
 public:
   ModuleDepCollector(std::unique_ptr<DependencyOutputOptions> Opts,
-                     CompilerInstance &I, DependencyConsumer &C);
+                     CompilerInstance &I, DependencyConsumer &C,
+                     std::map<std::string, std::string> PrebuiltModuleFiles);
 
   void attachToPreprocessor(Preprocessor &PP) override;
   void attachToASTReader(ASTReader &R) override;
@@ -181,6 +186,12 @@
   std::unordered_map<const Module *, ModuleDeps> ModularDeps;
   /// Options that control the dependency output generation.
   std::unique_ptr<DependencyOutputOptions> Opts;
+  /// Mapping between module names to module files that have been built prior to
+  /// the dependency scan.
+  std::map<std::string, std::string> PrebuiltModuleFiles;
+
+  CompilerInvocation
+  makeInvocationForModuleBuildWithoutPaths(const ModuleDeps &Deps) const;
 };
 
 } // end namespace dependencies
diff --git a/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp b/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
--- a/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
+++ b/clang/lib/Tooling/DependencyScanning/DependencyScanningWorker.cpp
@@ -45,6 +45,23 @@
   DependencyConsumer &C;
 };
 
+/// A listener that collects the names and paths to imported modules.
+class ImportCollectingListener : public ASTReaderListener {
+public:
+  ImportCollectingListener(
+      std::map<std::string, std::string> &PrebuiltModuleFiles)
+      : PrebuiltModuleFiles(PrebuiltModuleFiles) {}
+
+  bool needsImportVisitation() const override { return true; }
+
+  void visitImport(StringRef ModuleName, StringRef Filename) override {
+    PrebuiltModuleFiles[std::string(ModuleName)] = std::string(Filename);
+  }
+
+private:
+  std::map<std::string, std::string> &PrebuiltModuleFiles;
+};
+
 /// A clang tool that runs the preprocessor in a mode that's optimized for
 /// dependency scanning for the given compiler invocation.
 class DependencyScanningAction : public tooling::ToolAction {
@@ -101,6 +118,22 @@
     Compiler.setFileManager(FileMgr);
     Compiler.createSourceManager(*FileMgr);
 
+    std::map<std::string, std::string> PrebuiltModuleFiles;
+    if (!Compiler.getPreprocessorOpts().ImplicitPCHInclude.empty()) {
+      /// Collect the modules that were prebuilt as part of the PCH.
+      ImportCollectingListener Listener(PrebuiltModuleFiles);
+      ASTReader::readASTFileControlBlock(
+          Compiler.getPreprocessorOpts().ImplicitPCHInclude,
+          Compiler.getFileManager(), Compiler.getPCHContainerReader(),
+          /*FindModuleFileExtensions=*/false, Listener,
+          /*ValidateDiagnosticOptions=*/false);
+    }
+    /// Configure the compiler with prebuilt modules. This will prevent it from
+    /// inventing new modules and instead force it to reuse whatever the PCH
+    /// already contains.
+    Compiler.getHeaderSearchOpts().PrebuiltModuleFiles.insert(
+        PrebuiltModuleFiles.begin(), PrebuiltModuleFiles.end());
+
     // Create the dependency collector that will collect the produced
     // dependencies.
     //
@@ -122,7 +155,7 @@
       break;
     case ScanningOutputFormat::Full:
       Compiler.addDependencyCollector(std::make_shared<ModuleDepCollector>(
-          std::move(Opts), Compiler, Consumer));
+          std::move(Opts), Compiler, Consumer, std::move(PrebuiltModuleFiles)));
       break;
     }
 
diff --git a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
--- a/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
+++ b/clang/lib/Tooling/DependencyScanning/ModuleDepCollector.cpp
@@ -18,9 +18,9 @@
 using namespace tooling;
 using namespace dependencies;
 
-static CompilerInvocation
-makeInvocationForModuleBuildWithoutPaths(const ModuleDeps &Deps,
-                                         const CompilerInvocation &Invocation) {
+CompilerInvocation ModuleDepCollector::makeInvocationForModuleBuildWithoutPaths(
+    const ModuleDeps &Deps) const {
+  const CompilerInvocation &Invocation = Instance.getInvocation();
   // Make a deep copy of the invocation.
   CompilerInvocation CI(Invocation);
 
@@ -34,6 +34,19 @@
 
   CI.getLangOpts()->ImplicitModules = false;
 
+  // The HeaderSearchOptions::PrebuiltModuleFiles that were injected into the
+  // original CompilerInvocation were an over-approximation. Check which ones
+  // were actually used in the module and pass them as FrontendOpts::ModuleFiles
+  // instead.
+  for (const auto &PrebuiltModuleFile : PrebuiltModuleFiles) {
+    CI.getHeaderSearchOpts().PrebuiltModuleFiles.erase(
+        PrebuiltModuleFile.first);
+    if (Deps.FileDeps.contains(PrebuiltModuleFile.second))
+      CI.getFrontendOpts().ModuleFiles.push_back(PrebuiltModuleFile.second);
+  }
+
+  CI.getPreprocessorOpts().ImplicitPCHInclude.clear();
+
   return CI;
 }
 
@@ -148,7 +161,15 @@
     return;
 
   const Module *TopLevelModule = Imported->getTopLevelModule();
-  DirectModularDeps.insert(TopLevelModule);
+
+  auto PrebuiltModuleIt = MDC.PrebuiltModuleFiles.find(
+      TopLevelModule->getTopLevelModuleName().str());
+  // Don't add prebuilt modules to modular dependencies. The original
+  // command-line already contains these and we report them (or their parent) as
+  // file dependencies. We don't want to report them as modular dependencies,
+  // since they don't need to be built.
+  if (PrebuiltModuleIt == MDC.PrebuiltModuleFiles.end())
+    DirectModularDeps.insert(TopLevelModule);
 }
 
 void ModuleDepCollectorPP::EndOfMainFile() {
@@ -206,8 +227,12 @@
         MD.FileDeps.insert(IF.getFile()->getName());
       });
 
-  MD.Invocation =
-      makeInvocationForModuleBuildWithoutPaths(MD, Instance.getInvocation());
+  // Add direct prebuilt module dependencies now, so that we can use them when
+  // creating a CompilerInvocation and computing context hash for this
+  // ModuleDeps instance.
+  addDirectPrebuiltModuleDeps(M, MD);
+
+  MD.Invocation = MDC.makeInvocationForModuleBuildWithoutPaths(MD);
   MD.ID.ContextHash = MD.Invocation.getModuleHash();
 
   llvm::DenseSet<const Module *> AddedModules;
@@ -216,6 +241,18 @@
   return MD.ID;
 }
 
+void ModuleDepCollectorPP::addDirectPrebuiltModuleDeps(const Module *M,
+                                                       ModuleDeps &MD) {
+  for (const Module *Import : M->Imports) {
+    if (Import->getTopLevelModule() != M->getTopLevelModule()) {
+      auto PrebuiltModuleIt =
+          MDC.PrebuiltModuleFiles.find(Import->getTopLevelModuleName().str());
+      if (PrebuiltModuleIt != MDC.PrebuiltModuleFiles.end())
+        MD.FileDeps.insert(PrebuiltModuleIt->second);
+    }
+  }
+}
+
 void ModuleDepCollectorPP::addAllSubmoduleDeps(
     const Module *M, ModuleDeps &MD,
     llvm::DenseSet<const Module *> &AddedModules) {
@@ -229,7 +266,9 @@
     const Module *M, ModuleDeps &MD,
     llvm::DenseSet<const Module *> &AddedModules) {
   for (const Module *Import : M->Imports) {
-    if (Import->getTopLevelModule() != M->getTopLevelModule()) {
+    if (Import->getTopLevelModule() != M->getTopLevelModule() &&
+        MDC.PrebuiltModuleFiles.find(Import->getTopLevelModuleName().str()) ==
+            MDC.PrebuiltModuleFiles.end()) {
       ModuleID ImportID = handleTopLevelModule(Import->getTopLevelModule());
       if (AddedModules.insert(Import->getTopLevelModule()).second)
         MD.ClangModuleDeps.push_back(ImportID);
@@ -239,8 +278,10 @@
 
 ModuleDepCollector::ModuleDepCollector(
     std::unique_ptr<DependencyOutputOptions> Opts, CompilerInstance &I,
-    DependencyConsumer &C)
-    : Instance(I), Consumer(C), Opts(std::move(Opts)) {}
+    DependencyConsumer &C,
+    std::map<std::string, std::string> PrebuiltModuleFiles)
+    : Instance(I), Consumer(C), Opts(std::move(Opts)),
+      PrebuiltModuleFiles(std::move(PrebuiltModuleFiles)) {}
 
 void ModuleDepCollector::attachToPreprocessor(Preprocessor &PP) {
   PP.addPPCallbacks(std::make_unique<ModuleDepCollectorPP>(Instance, *this));
diff --git a/clang/test/ClangScanDeps/Inputs/modules-pch/cdb_pch.json b/clang/test/ClangScanDeps/Inputs/modules-pch/cdb_pch.json
new file mode 100644
--- /dev/null
+++ b/clang/test/ClangScanDeps/Inputs/modules-pch/cdb_pch.json
@@ -0,0 +1,7 @@
+[
+  {
+    "directory": "DIR",
+    "command": "clang -x c-header DIR/pch.h -fmodules -gmodules -fimplicit-module-maps -fmodules-cache-path=DIR/cache -o DIR/pch.h.gch",
+    "file": "DIR/pch.h"
+  }
+]
diff --git a/clang/test/ClangScanDeps/Inputs/modules-pch/cdb_tu_with_common.json b/clang/test/ClangScanDeps/Inputs/modules-pch/cdb_tu_with_common.json
new file mode 100644
--- /dev/null
+++ b/clang/test/ClangScanDeps/Inputs/modules-pch/cdb_tu_with_common.json
@@ -0,0 +1,7 @@
+[
+  {
+    "directory": "DIR",
+    "command": "clang -fsyntax-only DIR/tu_with_common.c -fmodules -gmodules -fimplicit-module-maps -fmodules-cache-path=DIR/cache -include DIR/pch.h -o DIR/tu_with_common.o",
+    "file": "DIR/tu_with_common.c"
+  }
+]
diff --git a/clang/test/ClangScanDeps/Inputs/modules-pch/mod_common_1.h b/clang/test/ClangScanDeps/Inputs/modules-pch/mod_common_1.h
new file mode 100644
--- /dev/null
+++ b/clang/test/ClangScanDeps/Inputs/modules-pch/mod_common_1.h
@@ -0,0 +1 @@
+// mod_common_1.h
diff --git a/clang/test/ClangScanDeps/Inputs/modules-pch/mod_common_2.h b/clang/test/ClangScanDeps/Inputs/modules-pch/mod_common_2.h
new file mode 100644
--- /dev/null
+++ b/clang/test/ClangScanDeps/Inputs/modules-pch/mod_common_2.h
@@ -0,0 +1 @@
+// mod_common_2.h
diff --git a/clang/test/ClangScanDeps/Inputs/modules-pch/mod_pch.h b/clang/test/ClangScanDeps/Inputs/modules-pch/mod_pch.h
new file mode 100644
--- /dev/null
+++ b/clang/test/ClangScanDeps/Inputs/modules-pch/mod_pch.h
@@ -0,0 +1,3 @@
+// mod_pch.h
+
+#include "mod_common_2.h"
diff --git a/clang/test/ClangScanDeps/Inputs/modules-pch/mod_tu_with_common.h b/clang/test/ClangScanDeps/Inputs/modules-pch/mod_tu_with_common.h
new file mode 100644
--- /dev/null
+++ b/clang/test/ClangScanDeps/Inputs/modules-pch/mod_tu_with_common.h
@@ -0,0 +1,3 @@
+// mod_tu_with_common.h
+
+#include "mod_common_1.h"
diff --git a/clang/test/ClangScanDeps/Inputs/modules-pch/module.modulemap b/clang/test/ClangScanDeps/Inputs/modules-pch/module.modulemap
--- a/clang/test/ClangScanDeps/Inputs/modules-pch/module.modulemap
+++ b/clang/test/ClangScanDeps/Inputs/modules-pch/module.modulemap
@@ -1,3 +1,19 @@
+module ModCommon1 {
+    header "mod_common_1.h"
+}
+
+module ModCommon2 {
+    header "mod_common_2.h"
+}
+
+module ModPCH {
+    header "mod_pch.h"
+}
+
 module ModTU {
     header "mod_tu.h"
 }
+
+module ModTUWithCommon {
+    header "mod_tu_with_common.h"
+}
diff --git a/clang/test/ClangScanDeps/Inputs/modules-pch/pch.h b/clang/test/ClangScanDeps/Inputs/modules-pch/pch.h
--- a/clang/test/ClangScanDeps/Inputs/modules-pch/pch.h
+++ b/clang/test/ClangScanDeps/Inputs/modules-pch/pch.h
@@ -1 +1,4 @@
 // pch.h
+
+#include "mod_common_1.h"
+#include "mod_pch.h"
diff --git a/clang/test/ClangScanDeps/Inputs/modules-pch/tu_with_common.c b/clang/test/ClangScanDeps/Inputs/modules-pch/tu_with_common.c
new file mode 100644
--- /dev/null
+++ b/clang/test/ClangScanDeps/Inputs/modules-pch/tu_with_common.c
@@ -0,0 +1,4 @@
+// tu_with_common.c
+
+#include "mod_common_2.h"
+#include "mod_tu_with_common.h"
diff --git a/clang/test/ClangScanDeps/modules-pch.c b/clang/test/ClangScanDeps/modules-pch.c
--- a/clang/test/ClangScanDeps/modules-pch.c
+++ b/clang/test/ClangScanDeps/modules-pch.c
@@ -1,10 +1,124 @@
 // RUN: rm -rf %t && mkdir %t
 // RUN: cp %S/Inputs/modules-pch/* %t
 
+// Scan dependencies of the PCH:
+//
+// RUN: sed "s|DIR|%/t|g" %S/Inputs/modules-pch/cdb_pch.json > %t/cdb_pch.json
+// RUN: echo -%t > %t/result_pch.json
+// RUN: clang-scan-deps -compilation-database %t/cdb_pch.json -format experimental-full \
+// RUN:   -generate-modules-path-args -build-dir %t/build -mode preprocess >> %t/result_pch.json
+// RUN: cat %t/result_pch.json | FileCheck %s -check-prefix=CHECK-PCH
+//
+// CHECK-PCH:      -[[PREFIX:.*]]
+// CHECK-PCH-NEXT: {
+// CHECK-PCH-NEXT:   "modules": [
+// CHECK-PCH-NEXT:     {
+// CHECK-PCH-NEXT:       "clang-module-deps": [],
+// CHECK-PCH-NEXT:       "clang-modulemap-file": "[[PREFIX]]/module.modulemap",
+// CHECK-PCH-NEXT:       "command-line": [
+// CHECK-PCH-NEXT:         "-cc1"
+// CHECK-PCH:              "-emit-module"
+// CHECK-PCH:              "-fmodules"
+// CHECK-PCH:              "-fmodule-name=ModCommon1"
+// CHECK-PCH:              "-fno-implicit-modules"
+// CHECK-PCH:            ],
+// CHECK-PCH-NEXT:       "context-hash": "[[HASH_MOD_COMMON_1:.*]]",
+// CHECK-PCH-NEXT:       "file-deps": [
+// CHECK-PCH-NEXT:         "[[PREFIX]]/mod_common_1.h",
+// CHECK-PCH-NEXT:         "[[PREFIX]]/module.modulemap"
+// CHECK-PCH-NEXT:       ],
+// CHECK-PCH-NEXT:       "name": "ModCommon1"
+// CHECK-PCH-NEXT:     },
+// CHECK-PCH-NEXT:     {
+// CHECK-PCH-NEXT:       "clang-module-deps": [],
+// CHECK-PCH-NEXT:       "clang-modulemap-file": "[[PREFIX]]/module.modulemap",
+// CHECK-PCH-NEXT:       "command-line": [
+// CHECK-PCH-NEXT:         "-cc1"
+// CHECK-PCH:              "-emit-module"
+// CHECK-PCH:              "-fmodules"
+// CHECK-PCH:              "-fmodule-name=ModCommon2"
+// CHECK-PCH:              "-fno-implicit-modules"
+// CHECK-PCH:            ],
+// CHECK-PCH-NEXT:       "context-hash": "[[HASH_MOD_COMMON_2:.*]]",
+// CHECK-PCH-NEXT:       "file-deps": [
+// CHECK-PCH-NEXT:         "[[PREFIX]]/mod_common_2.h",
+// CHECK-PCH-NEXT:         "[[PREFIX]]/module.modulemap"
+// CHECK-PCH-NEXT:       ],
+// CHECK-PCH-NEXT:       "name": "ModCommon2"
+// CHECK-PCH-NEXT:     },
+// CHECK-PCH-NEXT:     {
+// CHECK-PCH-NEXT:       "clang-module-deps": [
+// CHECK-PCH-NEXT:         {
+// CHECK-PCH-NEXT:           "context-hash": "[[HASH_MOD_COMMON_2]]",
+// CHECK-PCH-NEXT:           "module-name": "ModCommon2"
+// CHECK-PCH-NEXT:         }
+// CHECK-PCH-NEXT:       ],
+// CHECK-PCH-NEXT:       "clang-modulemap-file": "[[PREFIX]]/module.modulemap",
+// CHECK-PCH-NEXT:       "command-line": [
+// CHECK-PCH-NEXT:         "-cc1"
+// CHECK-PCH:              "-fmodule-map-file=[[PREFIX]]/module.modulemap"
+// CHECK-PCH:              "-emit-module"
+// CHECK-PCH:              "-fmodule-file=[[PREFIX]]/build/[[HASH_MOD_COMMON_2]]/ModCommon2-{{.*}}.pcm"
+// CHECK-PCH:              "-fmodules"
+// CHECK-PCH:              "-fmodule-name=ModPCH"
+// CHECK-PCH:              "-fno-implicit-modules"
+// CHECK-PCH:            ],
+// CHECK-PCH-NEXT:       "context-hash": "[[HASH_MOD_PCH:.*]]",
+// CHECK-PCH-NEXT:       "file-deps": [
+// CHECK-PCH-NEXT:         "[[PREFIX]]/mod_pch.h",
+// CHECK-PCH-NEXT:         "[[PREFIX]]/module.modulemap"
+// CHECK-PCH-NEXT:       ],
+// CHECK-PCH-NEXT:       "name": "ModPCH"
+// CHECK-PCH-NEXT:     }
+// CHECK-PCH-NEXT:   ],
+// CHECK-PCH-NEXT:   "translation-units": [
+// CHECK-PCH-NEXT:     {
+// CHECK-PCH-NEXT:       "clang-context-hash": "[[HASH_PCH:.*]]",
+// CHECK-PCH-NEXT:       "clang-module-deps": [
+// CHECK-PCH-NEXT:         {
+// CHECK-PCH-NEXT:           "context-hash": "[[HASH_MOD_COMMON_1]]",
+// CHECK-PCH-NEXT:           "module-name": "ModCommon1"
+// CHECK-PCH-NEXT:         },
+// CHECK-PCH-NEXT:         {
+// CHECK-PCH-NEXT:           "context-hash": "[[HASH_MOD_PCH]]",
+// CHECK-PCH-NEXT:           "module-name": "ModPCH"
+// CHECK-PCH-NEXT:         }
+// CHECK-PCH-NEXT:       ],
+// CHECK-PCH-NEXT:       "command-line": [
+// CHECK-PCH-NEXT:         "-fno-implicit-modules",
+// CHECK-PCH-NEXT:         "-fno-implicit-module-maps",
+// CHECK-PCH-DAG:          "-fmodule-file=[[PREFIX]]/build/[[HASH_MOD_COMMON_1]]/ModCommon1-{{.*}}.pcm",
+// CHECK-PCH-DAG:          "-fmodule-file=[[PREFIX]]/build/[[HASH_MOD_COMMON_2]]/ModCommon2-{{.*}}.pcm",
+// CHECK-PCH-DAG:          "-fmodule-file=[[PREFIX]]/build/[[HASH_MOD_PCH]]/ModPCH-{{.*}}.pcm",
+// CHECK-PCH-NEXT:         "-fmodule-map-file=[[PREFIX]]/module.modulemap",
+// CHECK-PCH-NEXT:         "-fmodule-map-file=[[PREFIX]]/module.modulemap",
+// CHECK-PCH-NEXT:         "-fmodule-map-file=[[PREFIX]]/module.modulemap"
+// CHECK-PCH-NEXT:       ],
+// CHECK-PCH-NEXT:       "file-deps": [
+// CHECK-PCH-NEXT:         "[[PREFIX]]/pch.h"
+// CHECK-PCH-NEXT:       ],
+// CHECK-PCH-NEXT:       "input-file": "[[PREFIX]]/pch.h"
+// CHECK-PCH-NEXT:     }
+// CHECK-PCH-NEXT:   ]
+// CHECK-PCH-NEXT: }
+
 // Explicitly build the PCH:
 //
+// RUN: tail -n +2 %t/result_pch.json > %t/result_pch_stripped.json
+// RUN: %python %S/../../utils/module-deps-to-rsp.py %t/result_pch_stripped.json \
+// RUN:   --module-name=ModCommon1 > %t/mod_common_1.cc1.rsp
+// RUN: %python %S/../../utils/module-deps-to-rsp.py %t/result_pch_stripped.json \
+// RUN:   --module-name=ModCommon2 > %t/mod_common_2.cc1.rsp
+// RUN: %python %S/../../utils/module-deps-to-rsp.py %t/result_pch_stripped.json \
+// RUN:   --module-name=ModPCH > %t/mod_pch.cc1.rsp
+// RUN: %python %S/../../utils/module-deps-to-rsp.py %t/result_pch_stripped.json \
+// RUN:   --tu-index=0 > %t/pch.rsp
+//
+// RUN: %clang @%t/mod_common_1.cc1.rsp
+// RUN: %clang @%t/mod_common_2.cc1.rsp
+// RUN: %clang @%t/mod_pch.cc1.rsp
 // RUN: %clang -x c-header %t/pch.h -fmodules -gmodules -fimplicit-module-maps \
-// RUN:   -fmodules-cache-path=%t/cache -o %t/pch.h.gch -fno-implicit-modules -fno-implicit-module-maps
+// RUN:   -fmodules-cache-path=%t/cache -o %t/pch.h.gch @%t/pch.rsp
 
 // Scan dependencies of the TU:
 //
@@ -57,3 +171,81 @@
 // CHECK-TU-NEXT:     }
 // CHECK-TU-NEXT:   ]
 // CHECK-TU-NEXT: }
+
+// Explicitly build the TU:
+//
+// RUN: tail -n +2 %t/result_tu.json > %t/result_tu_stripped.json
+// RUN: %python %S/../../utils/module-deps-to-rsp.py %t/result_tu_stripped.json \
+// RUN:   --module-name=ModTU > %t/mod_tu.cc1.rsp
+// RUN: %python %S/../../utils/module-deps-to-rsp.py %t/result_tu_stripped.json \
+// RUN:   --tu-index=0 > %t/tu.rsp
+//
+// RUN: %clang @%t/mod_tu.cc1.rsp
+// RUN: %clang -fsyntax-only %s -fmodules -gmodules -fimplicit-module-maps \
+// RUN:   -fmodules-cache-path=%t/cache -include %t/pch.h -o %t/tu.o @%t/tu.rsp
+
+// Scan dependencies of the TU that has common modules with the PCH:
+//
+// RUN: sed "s|DIR|%/t|g" %S/Inputs/modules-pch/cdb_tu_with_common.json > %t/cdb_tu_with_common.json
+// RUN: echo -%t > %t/result_tu_with_common.json
+// RUN: clang-scan-deps -compilation-database %t/cdb_tu_with_common.json -format experimental-full \
+// RUN:   -generate-modules-path-args -build-dir %t/build -mode preprocess >> %t/result_tu_with_common.json
+// RUN: cat %t/result_tu_with_common.json | FileCheck %s -check-prefix=CHECK-TU-WITH-COMMON
+//
+// CHECK-TU-WITH-COMMON:      -[[PREFIX:.*]]
+// CHECK-TU-WITH-COMMON-NEXT: {
+// CHECK-TU-WITH-COMMON-NEXT:   "modules": [
+// CHECK-TU-WITH-COMMON-NEXT:     {
+// CHECK-TU-WITH-COMMON-NEXT:       "clang-module-deps": [],
+// CHECK-TU-WITH-COMMON-NEXT:       "clang-modulemap-file": "[[PREFIX]]/module.modulemap",
+// CHECK-TU-WITH-COMMON-NEXT:       "command-line": [
+// CHECK-TU-WITH-COMMON-NEXT:         "-cc1",
+// CHECK-TU-WITH-COMMON:              "-emit-module",
+// CHECK-TU-WITH-COMMON:              "-fmodule-file=[[PREFIX]]/build/{{.*}}/ModCommon1-{{.*}}.pcm",
+// CHECK-TU-WITH-COMMON:              "-fmodule-name=ModTUWithCommon",
+// CHECK-TU-WITH-COMMON:              "-fno-implicit-modules",
+// CHECK-TU-WITH-COMMON:            ],
+// CHECK-TU-WITH-COMMON-NEXT:       "context-hash": "[[HASH_MOD_TU_WITH_COMMON:.*]]",
+// CHECK-TU-WITH-COMMON-NEXT:       "file-deps": [
+// CHECK-TU-WITH-COMMON-NEXT:         "[[PREFIX]]/build/{{.*}}/ModCommon1-{{.*}}.pcm",
+// CHECK-TU-WITH-COMMON-NEXT:         "[[PREFIX]]/mod_tu_with_common.h",
+// CHECK-TU-WITH-COMMON-NEXT:         "[[PREFIX]]/module.modulemap"
+// CHECK-TU-WITH-COMMON-NEXT:       ],
+// CHECK-TU-WITH-COMMON-NEXT:       "name": "ModTUWithCommon"
+// CHECK-TU-WITH-COMMON-NEXT:     }
+// CHECK-TU-WITH-COMMON-NEXT:   ],
+// CHECK-TU-WITH-COMMON-NEXT:   "translation-units": [
+// CHECK-TU-WITH-COMMON-NEXT:     {
+// CHECK-TU-WITH-COMMON-NEXT:       "clang-context-hash": "[[HASH_TU_WITH_COMMON:.*]]",
+// CHECK-TU-WITH-COMMON-NEXT:       "clang-module-deps": [
+// CHECK-TU-WITH-COMMON-NEXT:         {
+// CHECK-TU-WITH-COMMON-NEXT:           "context-hash": "[[HASH_MOD_TU_WITH_COMMON]]",
+// CHECK-TU-WITH-COMMON-NEXT:           "module-name": "ModTUWithCommon"
+// CHECK-TU-WITH-COMMON-NEXT:         }
+// CHECK-TU-WITH-COMMON-NEXT:       ],
+// CHECK-TU-WITH-COMMON-NEXT:       "command-line": [
+// CHECK-TU-WITH-COMMON-NEXT:         "-fno-implicit-modules",
+// CHECK-TU-WITH-COMMON-NEXT:         "-fno-implicit-module-maps",
+// CHECK-TU-WITH-COMMON-NEXT:         "-fmodule-file=[[PREFIX]]/build/[[HASH_MOD_TU_WITH_COMMON]]/ModTUWithCommon-{{.*}}.pcm",
+// CHECK-TU-WITH-COMMON-NEXT:         "-fmodule-map-file=[[PREFIX]]/module.modulemap"
+// CHECK-TU-WITH-COMMON-NEXT:       ],
+// CHECK-TU-WITH-COMMON-NEXT:       "file-deps": [
+// CHECK-TU-WITH-COMMON-NEXT:         "[[PREFIX]]/tu_with_common.c",
+// CHECK-TU-WITH-COMMON-NEXT:         "[[PREFIX]]/pch.h.gch"
+// CHECK-TU-WITH-COMMON-NEXT:       ],
+// CHECK-TU-WITH-COMMON-NEXT:       "input-file": "[[PREFIX]]/tu_with_common.c"
+// CHECK-TU-WITH-COMMON-NEXT:     }
+// CHECK-TU-WITH-COMMON-NEXT:   ]
+// CHECK-TU-WITH-COMMON-NEXT: }
+
+// Explicitly build the TU that has common modules with the PCH:
+//
+// RUN: tail -n +2 %t/result_tu_with_common.json > %t/result_tu_with_common_stripped.json
+// RUN: %python %S/../../utils/module-deps-to-rsp.py %t/result_tu_with_common_stripped.json \
+// RUN:   --module-name=ModTUWithCommon > %t/mod_tu_with_common.cc1.rsp
+// RUN: %python %S/../../utils/module-deps-to-rsp.py %t/result_tu_with_common_stripped.json \
+// RUN:   --tu-index=0 > %t/tu_with_common.rsp
+//
+// RUN: %clang @%t/mod_tu_with_common.cc1.rsp
+// RUN: %clang -fsyntax-only %s -fmodules -gmodules -fimplicit-module-maps \
+// RUN:   -fmodules-cache-path=%t/cache -include %t/pch.h -o %t/tu.o @%t/tu_with_common.rsp