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
@@ -42,6 +42,16 @@
   /// Modules with the same name but a different \c ContextHash should be
   /// treated as separate modules for the purpose of a build.
   std::string ContextHash;
+
+  bool operator==(const ModuleID &Other) const {
+    return ModuleName == Other.ModuleName && ContextHash == Other.ContextHash;
+  }
+};
+
+struct ModuleIDHasher {
+  std::size_t operator()(const ModuleID &MID) const {
+    return llvm::hash_combine(MID.ModuleName, MID.ContextHash);
+  }
 };
 
 struct ModuleDeps {
diff --git a/clang/test/ClangScanDeps/modules-full.cpp b/clang/test/ClangScanDeps/modules-full.cpp
--- a/clang/test/ClangScanDeps/modules-full.cpp
+++ b/clang/test/ClangScanDeps/modules-full.cpp
@@ -20,6 +20,12 @@
 // RUN:   -generate-modules-path-args -mode preprocess-minimized-sources >> %t.result
 // RUN: cat %t.result | sed 's/\\/\//g' | FileCheck --check-prefixes=CHECK,CHECK-ABS %s
 //
+// RUN: echo %t.dir > %t.result
+// RUN: clang-scan-deps -compilation-database %t.cdb -j 4 -format experimental-full \
+// RUN:   -generate-modules-path-args -module-files-dir %t.dir/custom \
+// RUN:   -mode preprocess-minimized-sources >> %t.result
+// RUN: cat %t.result | sed 's/\\/\//g' | FileCheck --check-prefixes=CHECK,CHECK-CUSTOM %s
+//
 // RUN: echo %t.dir > %t_clangcl.result
 // RUN: clang-scan-deps -compilation-database %t_clangcl.cdb -j 4 -format experimental-full \
 // RUN:   -mode preprocess-minimized-sources >> %t_clangcl.result
@@ -45,9 +51,11 @@
 // CHECK-NEXT:         "-cc1"
 // CHECK-NO-ABS-NOT:   "-fmodule-map-file={{.*}}"
 // CHECK-ABS:          "-fmodule-map-file=[[PREFIX]]/Inputs/module.modulemap"
+// CHECK-CUSTOM:       "-fmodule-map-file=[[PREFIX]]/Inputs/module.modulemap"
 // CHECK:              "-emit-module"
 // CHECK-NO-ABS-NOT:   "-fmodule-file={{.*}}"
 // CHECK-ABS:          "-fmodule-file=[[PREFIX]]/module-cache{{(_clangcl)?}}/[[CONTEXT_HASH_H1]]/header2-{{[A-Z0-9]+}}.pcm"
+// CHECK-CUSTOM:       "-fmodule-file=[[PREFIX]]/custom/[[CONTEXT_HASH_H1]]/header2-{{[A-Z0-9]+}}.pcm"
 // CHECK:              "-fmodule-name=header1"
 // CHECK:              "-fno-implicit-modules"
 // CHECK:            ],
@@ -105,8 +113,10 @@
 // CHECK-NEXT:         "-fno-implicit-module-maps"
 // CHECK-NO-ABS-NOT:   "-fmodule-file={{.*}}"
 // CHECK-ABS-NEXT:     "-fmodule-file=[[PREFIX]]/module-cache{{(_clangcl)?}}/[[CONTEXT_HASH_H2]]/header1-{{[A-Z0-9]+}}.pcm"
+// CHECK-CUSTOM-NEXT:  "-fmodule-file=[[PREFIX]]/custom/[[CONTEXT_HASH_H2]]/header1-{{[A-Z0-9]+}}.pcm"
 // CHECK-NO-ABS-NOT:   "-fmodule-map-file={{.*}}"
 // CHECK-ABS-NEXT:     "-fmodule-map-file=[[PREFIX]]/Inputs/module.modulemap"
+// CHECK-CUSTOM-NEXT:  "-fmodule-map-file=[[PREFIX]]/Inputs/module.modulemap"
 // CHECK-NEXT:       ],
 // CHECK-NEXT:       "file-deps": [
 // CHECK-NEXT:         "[[PREFIX]]/modules_cdb_input.cpp"
@@ -126,8 +136,10 @@
 // CHECK-NEXT:         "-fno-implicit-module-maps"
 // CHECK-NO-ABS-NOT:   "-fmodule-file={{.*}},
 // CHECK-ABS-NEXT:     "-fmodule-file=[[PREFIX]]/module-cache{{(_clangcl)?}}/[[CONTEXT_HASH_H2]]/header1-{{[A-Z0-9]+}}.pcm"
+// CHECK-CUSTOM-NEXT:  "-fmodule-file=[[PREFIX]]/custom/[[CONTEXT_HASH_H2]]/header1-{{[A-Z0-9]+}}.pcm"
 // CHECK-NO-ABS-NOT:   "-fmodule-map-file={{.*}}
 // CHECK-ABS-NEXT:     "-fmodule-map-file=[[PREFIX]]/Inputs/module.modulemap"
+// CHECK-CUSTOM-NEXT:  "-fmodule-map-file=[[PREFIX]]/Inputs/module.modulemap"
 // CHECK-NEXT:       ],
 // CHECK-NEXT:       "file-deps": [
 // CHECK-NEXT:         "[[PREFIX]]/modules_cdb_input.cpp"
@@ -147,8 +159,10 @@
 // CHECK-NEXT:         "-fno-implicit-module-maps"
 // CHECK-NO-ABS-NOT:   "-fmodule-file={{.*}}"
 // CHECK-ABS-NEXT:     "-fmodule-file=[[PREFIX]]/module-cache{{(_clangcl)?}}/[[CONTEXT_HASH_H2]]/header1-{{[A-Z0-9]+}}.pcm"
+// CHECK-CUSTOM-NEXT:  "-fmodule-file=[[PREFIX]]/custom/[[CONTEXT_HASH_H2]]/header1-{{[A-Z0-9]+}}.pcm"
 // CHECK-NO-ABS-NOT:   "-fmodule-map-file={{.*}}"
 // CHECK-ABS-NEXT:     "-fmodule-map-file=[[PREFIX]]/Inputs/module.modulemap"
+// CHECK-CUSTOM-NEXT:  "-fmodule-map-file=[[PREFIX]]/Inputs/module.modulemap"
 // CHECK-NEXT:       ],
 // CHECK-NEXT:       "file-deps": [
 // CHECK-NEXT:         "[[PREFIX]]/modules_cdb_input.cpp"
@@ -169,9 +183,13 @@
 // CHECK-NO-ABS-NOT:   "-fmodule-file={{.*}}"
 // CHECK-ABS-NEXT:     "-fmodule-file=[[PREFIX]]/module-cache{{(_clangcl)?}}/[[CONTEXT_HASH_H1]]/header2-{{[A-Z0-9]+}}.pcm"
 // CHECK-ABS-NEXT:     "-fmodule-file=[[PREFIX]]/module-cache{{(_clangcl)?}}/[[CONTEXT_HASH_H1]]/header1-{{[A-Z0-9]+}}.pcm"
+// CHECK-CUSTOM-NEXT:  "-fmodule-file=[[PREFIX]]/custom/[[CONTEXT_HASH_H1]]/header2-{{[A-Z0-9]+}}.pcm"
+// CHECK-CUSTOM-NEXT:  "-fmodule-file=[[PREFIX]]/custom/[[CONTEXT_HASH_H1]]/header1-{{[A-Z0-9]+}}.pcm"
 // CHECK-NO-ABS-NOT:   "-fmodule-map-file={{.*}}"
 // CHECK-ABS-NEXT:     "-fmodule-map-file=[[PREFIX]]/Inputs/module.modulemap"
 // CHECK-ABS-NEXT:     "-fmodule-map-file=[[PREFIX]]/Inputs/module.modulemap"
+// CHECK-CUSTOM-NEXT:  "-fmodule-map-file=[[PREFIX]]/Inputs/module.modulemap"
+// CHECK-CUSTOM-NEXT:  "-fmodule-map-file=[[PREFIX]]/Inputs/module.modulemap"
 // CHECK-NEXT:       ],
 // CHECK-NEXT:       "file-deps": [
 // CHECK-NEXT:         "[[PREFIX]]/modules_cdb_input2.cpp"
diff --git a/clang/tools/clang-scan-deps/ClangScanDeps.cpp b/clang/tools/clang-scan-deps/ClangScanDeps.cpp
--- a/clang/tools/clang-scan-deps/ClangScanDeps.cpp
+++ b/clang/tools/clang-scan-deps/ClangScanDeps.cpp
@@ -163,6 +163,13 @@
         "'-fmodule-file=', '-o', '-fmodule-map-file='."),
     llvm::cl::init(false), llvm::cl::cat(DependencyScannerCategory));
 
+static llvm::cl::opt<std::string> ModuleFilesDir(
+    "module-files-dir",
+    llvm::cl::desc("With '-generate-modules-path-args', paths to module files "
+                   "in the generated command lines will begin with the "
+                   "specified directory instead the module cache directory."),
+    llvm::cl::cat(DependencyScannerCategory));
+
 llvm::cl::opt<unsigned>
     NumThreads("j", llvm::cl::Optional,
                llvm::cl::desc("Number of worker threads to use (default: use "
@@ -357,7 +364,22 @@
 
 private:
   StringRef lookupPCMPath(ModuleID MID) {
-    return Modules[IndexedModuleID{MID, 0}].ImplicitModulePCMPath;
+    auto PCMPath = PCMPaths.insert({MID, ""});
+    if (PCMPath.second)
+      PCMPath.first->second = constructPCMPath(lookupModuleDeps(MID));
+    return PCMPath.first->second;
+  }
+
+  /// Construct a path for the explicitly built PCM.
+  std::string constructPCMPath(const ModuleDeps &MD) const {
+    StringRef Filename = llvm::sys::path::filename(MD.ImplicitModulePCMPath);
+
+    SmallString<256> ExplicitPCMPath(
+        !ModuleFilesDir.empty()
+            ? ModuleFilesDir
+            : MD.Invocation.getHeaderSearchOpts().ModuleCachePath);
+    llvm::sys::path::append(ExplicitPCMPath, MD.ID.ContextHash, Filename);
+    return std::string(ExplicitPCMPath);
   }
 
   const ModuleDeps &lookupModuleDeps(ModuleID MID) {
@@ -395,6 +417,7 @@
   std::mutex Lock;
   std::unordered_map<IndexedModuleID, ModuleDeps, IndexedModuleIDHasher>
       Modules;
+  std::unordered_map<ModuleID, std::string, ModuleIDHasher> PCMPaths;
   std::vector<InputDeps> Inputs;
 };