diff --git a/clang/lib/Frontend/CompilerInstance.cpp b/clang/lib/Frontend/CompilerInstance.cpp
--- a/clang/lib/Frontend/CompilerInstance.cpp
+++ b/clang/lib/Frontend/CompilerInstance.cpp
@@ -441,6 +441,52 @@
       InitOpts.RemappedFilesKeepOriginalName);
 }
 
+namespace {
+// Helper to recursively read the module names for all modules we're adding.
+// We mark these as known and redirect any attempt to load that module to
+// the files we were handed.
+struct ReadModuleNames : ASTReaderListener {
+  Preprocessor &PP;
+  llvm::SmallVector<IdentifierInfo *, 8> LoadedModules;
+
+  ReadModuleNames(Preprocessor &PP) : PP(PP) {}
+
+  void ReadModuleName(StringRef ModuleName) override {
+    LoadedModules.push_back(PP.getIdentifierInfo(ModuleName));
+  }
+
+  void registerAll() {
+    ModuleMap &MM = PP.getHeaderSearchInfo().getModuleMap();
+    for (auto *II : LoadedModules)
+      MM.cacheModuleLoad(*II, MM.findModule(II->getName()));
+    LoadedModules.clear();
+  }
+
+  void markAllUnavailable() {
+    for (auto *II : LoadedModules) {
+      if (Module *M = PP.getHeaderSearchInfo().getModuleMap().findModule(
+              II->getName())) {
+        M->HasIncompatibleModuleFile = true;
+
+        // Mark module as available if the only reason it was unavailable
+        // was missing headers.
+        SmallVector<Module *, 2> Stack;
+        Stack.push_back(M);
+        while (!Stack.empty()) {
+          Module *Current = Stack.pop_back_val();
+          if (Current->IsUnimportable)
+            continue;
+          Current->IsAvailable = true;
+          Stack.insert(Stack.end(), Current->submodule_begin(),
+                       Current->submodule_end());
+        }
+      }
+    }
+    LoadedModules.clear();
+  }
+};
+} // namespace
+
 // Preprocessor
 
 void CompilerInstance::createPreprocessor(TranslationUnitKind TUKind) {
@@ -603,6 +649,11 @@
   for (auto &Listener : DependencyCollectors)
     Listener->attachToASTReader(*Reader);
 
+  auto Listener = std::make_unique<ReadModuleNames>(PP);
+  auto &ListenerRef = *Listener;
+  ASTReader::ListenerScope ReadModuleNamesListener(*Reader,
+                                                   std::move(Listener));
+
   switch (Reader->ReadAST(Path,
                           Preamble ? serialization::MK_Preamble
                                    : serialization::MK_PCH,
@@ -612,6 +663,7 @@
     // Set the predefines buffer as suggested by the PCH reader. Typically, the
     // predefines buffer will be empty.
     PP.setPredefines(Reader->getSuggestedPredefines());
+    ListenerRef.registerAll();
     return Reader;
 
   case ASTReader::Failure:
@@ -627,6 +679,7 @@
     break;
   }
 
+  ListenerRef.markAllUnavailable();
   Context.setExternalSource(nullptr);
   return nullptr;
 }
@@ -1634,52 +1687,6 @@
                *FrontendTimerGroup);
   llvm::TimeRegion TimeLoading(FrontendTimerGroup ? &Timer : nullptr);
 
-  // Helper to recursively read the module names for all modules we're adding.
-  // We mark these as known and redirect any attempt to load that module to
-  // the files we were handed.
-  struct ReadModuleNames : ASTReaderListener {
-    CompilerInstance &CI;
-    llvm::SmallVector<IdentifierInfo*, 8> LoadedModules;
-
-    ReadModuleNames(CompilerInstance &CI) : CI(CI) {}
-
-    void ReadModuleName(StringRef ModuleName) override {
-      LoadedModules.push_back(
-          CI.getPreprocessor().getIdentifierInfo(ModuleName));
-    }
-
-    void registerAll() {
-      ModuleMap &MM = CI.getPreprocessor().getHeaderSearchInfo().getModuleMap();
-      for (auto *II : LoadedModules)
-        MM.cacheModuleLoad(*II, MM.findModule(II->getName()));
-      LoadedModules.clear();
-    }
-
-    void markAllUnavailable() {
-      for (auto *II : LoadedModules) {
-        if (Module *M = CI.getPreprocessor()
-                            .getHeaderSearchInfo()
-                            .getModuleMap()
-                            .findModule(II->getName())) {
-          M->HasIncompatibleModuleFile = true;
-
-          // Mark module as available if the only reason it was unavailable
-          // was missing headers.
-          SmallVector<Module *, 2> Stack;
-          Stack.push_back(M);
-          while (!Stack.empty()) {
-            Module *Current = Stack.pop_back_val();
-            if (Current->IsUnimportable) continue;
-            Current->IsAvailable = true;
-            Stack.insert(Stack.end(),
-                         Current->submodule_begin(), Current->submodule_end());
-          }
-        }
-      }
-      LoadedModules.clear();
-    }
-  };
-
   // If we don't already have an ASTReader, create one now.
   if (!TheASTReader)
     createASTReader();
@@ -1691,7 +1698,7 @@
                                           SourceLocation())
         <= DiagnosticsEngine::Warning;
 
-  auto Listener = std::make_unique<ReadModuleNames>(*this);
+  auto Listener = std::make_unique<ReadModuleNames>(*PP);
   auto &ListenerRef = *Listener;
   ASTReader::ListenerScope ReadModuleNamesListener(*TheASTReader,
                                                    std::move(Listener));
diff --git a/clang/lib/Tooling/DependencyScanning/DependencyScanningTool.cpp b/clang/lib/Tooling/DependencyScanning/DependencyScanningTool.cpp
--- a/clang/lib/Tooling/DependencyScanning/DependencyScanningTool.cpp
+++ b/clang/lib/Tooling/DependencyScanning/DependencyScanningTool.cpp
@@ -38,7 +38,7 @@
   };
 
   for (const PrebuiltModuleDep &PMD : PrebuiltModuleDeps) {
-    Args.push_back("-fmodule-file=" + PMD.ModuleName + "=" + PMD.PCMFile);
+    Args.push_back("-fmodule-file=" + PMD.PCMFile);
     Args.push_back("-fmodule-map-file=" + PMD.ModuleMapFile);
   }
 
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
@@ -229,8 +229,7 @@
 // CHECK-TU-WITH-COMMON-NEXT:       "command-line": [
 // CHECK-TU-WITH-COMMON-NEXT:         "-fno-implicit-modules",
 // CHECK-TU-WITH-COMMON-NEXT:         "-fno-implicit-module-maps",
-// FIXME: Figure out why we need `=ModCommon2` here for Clang to pick up the PCM.
-// CHECK-TU-WITH-COMMON-NEXT:         "-fmodule-file=ModCommon2=[[PREFIX]]/build/{{.*}}/ModCommon2-{{.*}}.pcm",
+// CHECK-TU-WITH-COMMON-NEXT:         "-fmodule-file=[[PREFIX]]/build/{{.*}}/ModCommon2-{{.*}}.pcm",
 // CHECK-TU-WITH-COMMON-NEXT:         "-fmodule-map-file=[[PREFIX]]/module.modulemap"
 // 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"
diff --git a/clang/test/Modules/Inputs/pch-shared-module/mod.h b/clang/test/Modules/Inputs/pch-shared-module/mod.h
new file mode 100644
diff --git a/clang/test/Modules/Inputs/pch-shared-module/module.modulemap b/clang/test/Modules/Inputs/pch-shared-module/module.modulemap
new file mode 100644
--- /dev/null
+++ b/clang/test/Modules/Inputs/pch-shared-module/module.modulemap
@@ -0,0 +1 @@
+module mod { header "mod.h" }
diff --git a/clang/test/Modules/Inputs/pch-shared-module/pch.h b/clang/test/Modules/Inputs/pch-shared-module/pch.h
new file mode 100644
--- /dev/null
+++ b/clang/test/Modules/Inputs/pch-shared-module/pch.h
@@ -0,0 +1 @@
+#include "mod.h"
diff --git a/clang/test/Modules/pch-shared-module.c b/clang/test/Modules/pch-shared-module.c
new file mode 100644
--- /dev/null
+++ b/clang/test/Modules/pch-shared-module.c
@@ -0,0 +1,14 @@
+// rm -rf %t && mkdir %t
+
+// RUN: %clang_cc1 -fmodules -emit-module -fmodule-name=mod %S/Inputs/pch-shared-module/module.modulemap -o %t/mod.pcm
+
+// RUN: %clang_cc1 -fmodules -emit-pch %S/Inputs/pch-shared-module/pch.h -o %t/pch.h.gch \
+// RUN:   -fmodule-file=%t/mod.pcm -fmodule-map-file=%S/Inputs/pch-shared-module/module.modulemap
+
+// Check that `mod.pcm` is loaded correctly, even though it's imported by the PCH as well.
+// RUN: %clang_cc1 -fmodules -fsyntax-only %s -include-pch %t/pch.h.gch -I %S/Inputs/pch-shared-module \
+// RUN:   -fmodule-file=%t/mod.pcm -fmodule-map-file=%S/Inputs/pch-shared-module/module.modulemap -verify
+
+#include "mod.h"
+
+// expected-no-diagnostics