diff --git a/include/swift/AST/DiagnosticsFrontend.def b/include/swift/AST/DiagnosticsFrontend.def
index 9e8abe5412ad3..58309227dfe23 100644
--- a/include/swift/AST/DiagnosticsFrontend.def
+++ b/include/swift/AST/DiagnosticsFrontend.def
@@ -494,7 +494,6 @@ REMARK(replay_output, none, "replay output file '%0': key '%1'", (StringRef, Str
 REMARK(output_cache_miss, none, "cache miss output file '%0': key '%1'", (StringRef, StringRef))
 
 // CAS related diagnostics
-ERROR(error_create_cas, none, "failed to create CAS '%0' (%1)", (StringRef, StringRef))
 ERROR(error_invalid_cas_id, none, "invalid CASID '%0' (%1)", (StringRef, StringRef))
 ERROR(error_cas, none, "CAS error encountered: %0", (StringRef))
 
diff --git a/include/swift/AST/ModuleDependencies.h b/include/swift/AST/ModuleDependencies.h
index dde8b9ef26984..50b7a9ca98671 100644
--- a/include/swift/AST/ModuleDependencies.h
+++ b/include/swift/AST/ModuleDependencies.h
@@ -20,6 +20,7 @@
 
 #include "swift/Basic/LLVM.h"
 #include "swift/AST/Import.h"
+#include "clang/CAS/CASOptions.h"
 #include "clang/Tooling/DependencyScanning/DependencyScanningService.h"
 #include "clang/Tooling/DependencyScanning/DependencyScanningTool.h"
 #include "llvm/ADT/ArrayRef.h"
@@ -767,6 +768,9 @@ class SwiftDependencyScanningService {
     ModuleDependenciesKindMap ModuleDependenciesMap;
   };
 
+  /// The CASOption created the Scanning Service if used.
+  llvm::Optional<clang::CASOptions> CASOpts;
+
   /// The persistent Clang dependency scanner service
   Optional<clang::tooling::dependencies::DependencyScanningService>
       ClangScanningService;
@@ -863,7 +867,7 @@ class SwiftDependencyScanningService {
   void overlaySharedFilesystemCacheForCompilation(CompilerInstance &Instance);
 
   /// Setup caching service.
-  void setupCachingDependencyScanningService(CompilerInstance &Instance);
+  bool setupCachingDependencyScanningService(CompilerInstance &Instance);
 private:
   /// Enforce clients not being allowed to query this cache directly, it must be
   /// wrapped in an instance of `ModuleDependenciesCache`.
diff --git a/include/swift/Basic/LangOptions.h b/include/swift/Basic/LangOptions.h
index ccd39bb2a26cd..6423117361a6a 100644
--- a/include/swift/Basic/LangOptions.h
+++ b/include/swift/Basic/LangOptions.h
@@ -23,6 +23,7 @@
 #include "swift/Basic/LLVM.h"
 #include "swift/Basic/Version.h"
 #include "swift/Config.h"
+#include "clang/CAS/CASOptions.h"
 #include "llvm/ADT/ArrayRef.h"
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/SmallString.h"
@@ -820,7 +821,7 @@ namespace swift {
     std::string Optimization;
 
     /// clang CASOptions.
-    std::string CASPath;
+    llvm::Optional<clang::CASOptions> CASOpts;
 
     /// Cache key for imported bridging header.
     std::string BridgingHeaderPCHCacheKey;
diff --git a/include/swift/Frontend/CachingUtils.h b/include/swift/Frontend/CachingUtils.h
index 501a65415d38e..343de5ccdc3da 100644
--- a/include/swift/Frontend/CachingUtils.h
+++ b/include/swift/Frontend/CachingUtils.h
@@ -39,7 +39,7 @@ bool replayCachedCompilerOutputs(
     llvm::cas::ObjectStore &CAS, llvm::cas::ActionCache &Cache,
     llvm::cas::ObjectRef BaseKey, DiagnosticEngine &Diag,
     const FrontendInputsAndOutputs &InputsAndOutputs,
-    CachingDiagnosticsProcessor &CDP);
+    CachingDiagnosticsProcessor &CDP, bool CacheRemarks);
 
 /// Load the cached compile result from cache.
 std::unique_ptr<llvm::MemoryBuffer> loadCachedCompileResultFromCacheKey(
diff --git a/include/swift/Frontend/FrontendOptions.h b/include/swift/Frontend/FrontendOptions.h
index d19af926aafc8..b328bf417be7f 100644
--- a/include/swift/Frontend/FrontendOptions.h
+++ b/include/swift/Frontend/FrontendOptions.h
@@ -21,6 +21,7 @@
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/Optional.h"
 #include "llvm/ADT/StringMap.h"
+#include "clang/CAS/CASOptions.h"
 
 #include <string>
 #include <vector>
@@ -122,11 +123,17 @@ class FrontendOptions {
   /// The module for which we should verify all of the generic signatures.
   std::string VerifyGenericSignaturesInModule;
 
-  /// Use CAS.
-  bool EnableCAS = false;
+  /// Enable compiler caching.
+  bool EnableCaching = false;
 
-  /// The CAS Path.
-  std::string CASPath;
+  /// Enable compiler caching remarks.
+  bool EnableCachingRemarks = false;
+
+  /// Skip replaying outputs from cache.
+  bool CacheSkipReplay = false;
+
+  /// CASOptions
+  clang::CASOptions CASOpts;
 
   /// CASFS Root.
   std::vector<std::string> CASFSRootIDs;
diff --git a/include/swift/Option/FrontendOptions.td b/include/swift/Option/FrontendOptions.td
index b88be4acad09a..e9770c6ff6ace 100644
--- a/include/swift/Option/FrontendOptions.td
+++ b/include/swift/Option/FrontendOptions.td
@@ -1217,6 +1217,23 @@ def always_compile_output_files :
   Flag<["-"], "always-compile-output-files">,
   HelpText<"Always compile output files even it might not change the results">;
 
+// CAS/Caching related options.
+def allow_unstable_cache_key_for_testing: Flag<["-"], "allow-unstable-cache-key-for-testing">,
+  HelpText<"Allow compilation caching with unstable inputs for testing purpose">;
+
+def bridging_header_pch_key : Separate<["-"], "bridging-header-pch-key">,
+  HelpText<"Cache Key for bridging header pch">;
+
+def clang_include_tree: Flag<["-"], "clang-include-tree">,
+  HelpText<"Use clang include tree">;
+
+def cas_fs: Separate<["-"], "cas-fs">,
+  HelpText<"Root CASID for CAS FileSystem">, MetaVarName<"<cas-id>">;
+
+def clang_include_tree_root: Separate<["-"], "clang-include-tree-root">,
+  HelpText<"Clang Include Tree CASID">, MetaVarName<"<cas-id>">;
+
+
 def experimental_spi_only_imports :
   Flag<["-"], "experimental-spi-only-imports">,
   HelpText<"Enable use of @_spiOnly imports">;
diff --git a/include/swift/Option/Options.td b/include/swift/Option/Options.td
index dba97b91132e0..510242c95e092 100644
--- a/include/swift/Option/Options.td
+++ b/include/swift/Option/Options.td
@@ -1812,36 +1812,32 @@ def gcc_toolchain: Separate<["-"], "gcc-toolchain">,
   MetaVarName<"<path>">,
   HelpText<"Specify a directory where the clang importer and clang linker can find headers and libraries">;
 
-def cas_path: Separate<["-"], "cas-path">,
+def cache_compile_job:  Flag<["-"], "cache-compile-job">,
   Flags<[FrontendOption, NewDriverOnlyOption]>,
-  HelpText<"Path to CAS">, MetaVarName<"<path>">;
+  HelpText<"Enable compiler caching">;
 
-def allow_unstable_cache_key_for_testing: Flag<["-"], "allow-unstable-cache-key-for-testing">,
-  Flags<[FrontendOption, HelpHidden, NoDriverOption]>,
-  HelpText<"Allow compilation caching with unstable inputs for testing purpose">;
-
-def bridging_header_pch_key : Separate<["-"], "bridging-header-pch-key">,
-  Flags<[FrontendOption, HelpHidden, ArgumentIsPath]>,
-  HelpText<"Cache Key for bridging header pch">;
+def cache_remarks:  Flag<["-"], "cache-remarks">,
+  Flags<[FrontendOption, NewDriverOnlyOption]>,
+  HelpText<"Show remarks for compiler caching">;
 
-def clang_include_tree: Flag<["-"], "clang-include-tree">,
-  Flags<[FrontendOption, NoDriverOption]>,
-  HelpText<"Use clang include tree">;
+def cache_disable_replay:  Flag<["-"], "cache-disable-replay">,
+  Flags<[FrontendOption, NewDriverOnlyOption]>,
+  HelpText<"Skip loading the compilation result from cache">;
 
+def cas_path: Separate<["-"], "cas-path">,
+  Flags<[FrontendOption, NewDriverOnlyOption]>,
+  HelpText<"Path to CAS">, MetaVarName<"<path>">;
 
-// END ONLY SUPPORTED IN NEW DRIVER
+def cas_plugin_path: Separate<["-"], "cas-plugin-path">,
+  Flags<[FrontendOption, NewDriverOnlyOption]>,
+  HelpText<"Path to CAS Plugin">, MetaVarName<"<path>">;
 
-def enable_cas: Flag<["-"], "enable-cas">,
-  Flags<[FrontendOption, NoDriverOption]>,
-  HelpText<"Enable CAS for swift-frontend">;
+def cas_plugin_option: Separate<["-"], "cas-plugin-option">,
+  Flags<[FrontendOption, NewDriverOnlyOption]>,
+  HelpText<"Option pass to CAS Plugin">, MetaVarName<"<name>=<option>">;
 
-def cas_fs: Separate<["-"], "cas-fs">,
-  Flags<[FrontendOption, NoDriverOption]>,
-  HelpText<"Root CASID for CAS FileSystem">, MetaVarName<"<cas-id>">;
 
-def clang_include_tree_root: Separate<["-"], "clang-include-tree-root">,
-  Flags<[FrontendOption, NoDriverOption]>,
-  HelpText<"Clang Include Tree CASID">, MetaVarName<"<cas-id>">;
+// END ONLY SUPPORTED IN NEW DRIVER
 
 
 def plugin_search_Group : OptionGroup<"<plugin search options>">;
diff --git a/lib/AST/ModuleDependencies.cpp b/lib/AST/ModuleDependencies.cpp
index a4151aee3db06..3d0b5e4040773 100644
--- a/lib/AST/ModuleDependencies.cpp
+++ b/lib/AST/ModuleDependencies.cpp
@@ -417,12 +417,25 @@ void SwiftDependencyScanningService::overlaySharedFilesystemCacheForCompilation(
   Instance.getSourceMgr().setFileSystem(depFS);
 }
 
-void SwiftDependencyScanningService::setupCachingDependencyScanningService(
+bool SwiftDependencyScanningService::setupCachingDependencyScanningService(
     CompilerInstance &Instance) {
-  if (!Instance.getInvocation().getFrontendOptions().EnableCAS)
-    return;
+  if (!Instance.getInvocation().getFrontendOptions().EnableCaching)
+    return false;
+
+  if (CASOpts) {
+    // If CASOption matches, the service is initialized already.
+    if (*CASOpts == Instance.getInvocation().getFrontendOptions().CASOpts)
+      return false;
+
+    // CASOption mismatch, return error.
+    Instance.getDiags().diagnose(
+        SourceLoc(), diag::error_cas,
+        "conflicting CAS options used in scanning service");
+    return true;
+  }
 
   // Setup CAS.
+  CASOpts = Instance.getInvocation().getFrontendOptions().CASOpts;
   CAS = Instance.getSharedCASInstance();
 
   // Add SDKSetting file.
@@ -454,17 +467,12 @@ void SwiftDependencyScanningService::setupCachingDependencyScanningService(
   auto CachingFS =
       llvm::cas::createCachingOnDiskFileSystem(Instance.getObjectStore());
   if (!CachingFS) {
-    Instance.getDiags().diagnose(SourceLoc(), diag::error_create_cas,
-                                 "CachingOnDiskFS",
+    Instance.getDiags().diagnose(SourceLoc(), diag::error_cas,
                                  toString(CachingFS.takeError()));
-    return;
+    return true;
   }
   CacheFS = std::move(*CachingFS);
 
-  clang::CASOptions CASOpts;
-  CASOpts.CASPath = Instance.getInvocation().getFrontendOptions().CASPath;
-  CASOpts.ensurePersistentCAS();
-
   UseClangIncludeTree =
       Instance.getInvocation().getClangImporterOptions().UseClangIncludeTree;
   const clang::tooling::dependencies::ScanningOutputFormat ClangScanningFormat =
@@ -474,10 +482,13 @@ void SwiftDependencyScanningService::setupCachingDependencyScanningService(
 
   ClangScanningService.emplace(
       clang::tooling::dependencies::ScanningMode::DependencyDirectivesScan,
-      ClangScanningFormat, CASOpts, Instance.getSharedCASInstance(),
-      Instance.getSharedCacheInstance(),
+      ClangScanningFormat,
+      Instance.getInvocation().getFrontendOptions().CASOpts,
+      Instance.getSharedCASInstance(), Instance.getSharedCacheInstance(),
       UseClangIncludeTree ? nullptr : CacheFS,
       /* ReuseFileManager */ false, /* OptimizeArgs */ false);
+
+  return false;
 }
 
 SwiftDependencyScanningService::ContextSpecificGlobalCacheState *
@@ -611,8 +622,8 @@ Optional<const ModuleDependencyInfo *> ModuleDependenciesCache::findDependency(
                                                           scannerContextHash);
   // During a scan, only produce the cached source module info for the current
   // module under scan.
-  if (optionalDep.hasValue()) {
-    auto dep = optionalDep.getValue();
+  if (optionalDep) {
+    auto dep = *optionalDep;
     if (dep->getAsSwiftSourceModule() &&
         moduleName != mainScanModuleName &&
         moduleName != "DummyMainModuleForResolvingCrossImportOverlays") {
diff --git a/lib/ClangImporter/ClangImporter.cpp b/lib/ClangImporter/ClangImporter.cpp
index 56fce770ffad7..6a78249ab1eee 100644
--- a/lib/ClangImporter/ClangImporter.cpp
+++ b/lib/ClangImporter/ClangImporter.cpp
@@ -709,13 +709,28 @@ importer::getNormalInvocationArguments(
                                llvm::sys::path::get_separator() +
                                "apinotes").str());
 
-  if (!importerOpts.CASPath.empty()) {
-    invocationArgStrs.push_back("-Xclang");
-    invocationArgStrs.push_back("-fcas-path");
-    invocationArgStrs.push_back("-Xclang");
-    invocationArgStrs.push_back(importerOpts.CASPath);
+  if (importerOpts.CASOpts) {
     invocationArgStrs.push_back("-Xclang");
     invocationArgStrs.push_back("-fno-pch-timestamp");
+    if (!importerOpts.CASOpts->CASPath.empty()) {
+      invocationArgStrs.push_back("-Xclang");
+      invocationArgStrs.push_back("-fcas-path");
+      invocationArgStrs.push_back("-Xclang");
+      invocationArgStrs.push_back(importerOpts.CASOpts->CASPath);
+    }
+    if (!importerOpts.CASOpts->PluginPath.empty()) {
+      invocationArgStrs.push_back("-Xclang");
+      invocationArgStrs.push_back("-fcas-plugin-path");
+      invocationArgStrs.push_back("-Xclang");
+      invocationArgStrs.push_back(importerOpts.CASOpts->PluginPath);
+      for (auto Opt : importerOpts.CASOpts->PluginOptions) {
+        invocationArgStrs.push_back("-Xclang");
+        invocationArgStrs.push_back("-fcas-plugin-option");
+        invocationArgStrs.push_back("-Xclang");
+        invocationArgStrs.push_back(
+            (llvm::Twine(Opt.first) + "=" + Opt.second).str());
+      }
+    }
   }
 }
 
diff --git a/lib/ClangImporter/ClangModuleDependencyScanner.cpp b/lib/ClangImporter/ClangModuleDependencyScanner.cpp
index 0855acffb882a..7a0ebeac0849a 100644
--- a/lib/ClangImporter/ClangModuleDependencyScanner.cpp
+++ b/lib/ClangImporter/ClangModuleDependencyScanner.cpp
@@ -238,10 +238,21 @@ void ClangImporter::recordModuleDependencies(
     std::string IncludeTree =
         clangModuleDep.IncludeTreeID ? *clangModuleDep.IncludeTreeID : "";
 
-    if (!RootID.empty() || !IncludeTree.empty()) {
+    if (ctx.ClangImporterOpts.CASOpts) {
       swiftArgs.push_back("-enable-cas");
-      swiftArgs.push_back("-cas-path");
-      swiftArgs.push_back(ctx.ClangImporterOpts.CASPath);
+      if (!ctx.ClangImporterOpts.CASOpts->CASPath.empty()) {
+        swiftArgs.push_back("-cas-path");
+        swiftArgs.push_back(ctx.ClangImporterOpts.CASOpts->CASPath);
+      }
+      if (!ctx.ClangImporterOpts.CASOpts->PluginPath.empty()) {
+        swiftArgs.push_back("-cas-plugin-path");
+        swiftArgs.push_back(ctx.ClangImporterOpts.CASOpts->PluginPath);
+        for (auto Opt : ctx.ClangImporterOpts.CASOpts->PluginOptions) {
+          swiftArgs.push_back("-cas-plugin-option");
+          swiftArgs.push_back(
+              (llvm::Twine(Opt.first) + "=" + Opt.second).str());
+        }
+      }
     }
 
     if (!RootID.empty()) {
@@ -334,10 +345,20 @@ void ClangImporter::recordBridgingHeaderOptions(
 
   llvm::for_each(clangArgs, addClangArg);
 
-  if (!ctx.ClangImporterOpts.CASPath.empty()) {
+  if (ctx.ClangImporterOpts.CASOpts) {
     swiftArgs.push_back("-enable-cas");
-    swiftArgs.push_back("-cas-path");
-    swiftArgs.push_back(ctx.ClangImporterOpts.CASPath);
+    if (!ctx.ClangImporterOpts.CASOpts->CASPath.empty()) {
+      swiftArgs.push_back("-cas-path");
+      swiftArgs.push_back(ctx.ClangImporterOpts.CASOpts->CASPath);
+    }
+    if (!ctx.ClangImporterOpts.CASOpts->PluginPath.empty()) {
+      swiftArgs.push_back("-cas-plugin-path");
+      swiftArgs.push_back(ctx.ClangImporterOpts.CASOpts->PluginPath);
+      for (auto Opt : ctx.ClangImporterOpts.CASOpts->PluginOptions) {
+        swiftArgs.push_back("-cas-plugin-option");
+        swiftArgs.push_back((llvm::Twine(Opt.first) + "=" + Opt.second).str());
+      }
+    }
   }
 
   if (auto Tree = deps.IncludeTreeID) {
@@ -387,12 +408,12 @@ Optional<const ModuleDependencyInfo*> ClangImporter::getModuleDependencies(
   std::vector<std::string> commandLineArgs =
       getClangDepScanningInvocationArguments(ctx);
   auto optionalWorkingDir = computeClangWorkingDirectory(commandLineArgs, ctx);
-  if (!optionalWorkingDir.hasValue()) {
+  if (!optionalWorkingDir) {
     ctx.Diags.diagnose(SourceLoc(), diag::clang_dependency_scan_error,
                        "Missing '-working-directory' argument");
     return None;
   }
-  std::string workingDir = optionalWorkingDir.getValue();
+  std::string workingDir = *optionalWorkingDir;
 
   auto moduleCachePath = getModuleCachePathFromClang(getClangInstance());
   auto lookupModuleOutput =
@@ -452,12 +473,12 @@ bool ClangImporter::addBridgingHeaderDependencies(
   std::vector<std::string> commandLineArgs =
       getClangDepScanningInvocationArguments(ctx, StringRef(bridgingHeader));
   auto optionalWorkingDir = computeClangWorkingDirectory(commandLineArgs, ctx);
-  if (!optionalWorkingDir.hasValue()) {
+  if (!optionalWorkingDir) {
     ctx.Diags.diagnose(SourceLoc(), diag::clang_dependency_scan_error,
                        "Missing '-working-directory' argument");
     return true;
   }
-  std::string workingDir = optionalWorkingDir.getValue();
+  std::string workingDir = *optionalWorkingDir;
 
   auto moduleCachePath = getModuleCachePathFromClang(getClangInstance());
   auto lookupModuleOutput =
diff --git a/lib/DependencyScan/DependencyScanningTool.cpp b/lib/DependencyScan/DependencyScanningTool.cpp
index 6f67370390588..38a9383c616a0 100644
--- a/lib/DependencyScan/DependencyScanningTool.cpp
+++ b/lib/DependencyScan/DependencyScanningTool.cpp
@@ -279,7 +279,8 @@ DependencyScanningTool::initCompilerInstanceForScan(
   }
 
   // Setup the caching service after the instance finishes setup.
-  ScanningService->setupCachingDependencyScanningService(*Instance);
+  if (ScanningService->setupCachingDependencyScanningService(*Instance))
+    return std::make_error_code(std::errc::invalid_argument);
 
   (void)Instance->getMainModule();
 
diff --git a/lib/DependencyScan/ScanDependencies.cpp b/lib/DependencyScan/ScanDependencies.cpp
index 396a965d1e4d1..375342890cdbf 100644
--- a/lib/DependencyScan/ScanDependencies.cpp
+++ b/lib/DependencyScan/ScanDependencies.cpp
@@ -421,7 +421,7 @@ static llvm::Error resolveExplicitModuleInputs(
     dependencyInfoCopy.updateCommandLine(commandLine);
 
   // Handle CAS options.
-  if (instance.getInvocation().getFrontendOptions().EnableCAS) {
+  if (instance.getInvocation().getFrontendOptions().EnableCaching) {
     // Merge CASFS from clang dependency.
     auto &CASFS = cache.getScanService().getSharedCachingFS();
     auto &CAS = CASFS.getCAS();
@@ -1764,7 +1764,9 @@ bool swift::dependencies::scanDependencies(CompilerInstance &instance) {
     deserializeDependencyCache(instance, service);
   // Wrap the filesystem with a caching `DependencyScanningWorkerFilesystem`
   service.overlaySharedFilesystemCacheForCompilation(instance);
-  service.setupCachingDependencyScanningService(instance);
+  if (service.setupCachingDependencyScanningService(instance))
+    return true;
+
   ModuleDependenciesCache cache(service,
                                 instance.getMainModule()->getNameStr().str(),
                                 instance.getInvocation().getModuleScanningHash());
@@ -1832,7 +1834,9 @@ bool swift::dependencies::batchScanDependencies(
 
   SwiftDependencyScanningService singleUseService;
   singleUseService.overlaySharedFilesystemCacheForCompilation(instance);
-  singleUseService.setupCachingDependencyScanningService(instance);
+  if (singleUseService.setupCachingDependencyScanningService(instance))
+    return true;
+
   ModuleDependenciesCache cache(singleUseService,
                                 instance.getMainModule()->getNameStr().str(),
                                 instance.getInvocation().getModuleScanningHash());
diff --git a/lib/DriverTool/swift_cache_tool_main.cpp b/lib/DriverTool/swift_cache_tool_main.cpp
index 86c05d174633d..b4fabf06aee7b 100644
--- a/lib/DriverTool/swift_cache_tool_main.cpp
+++ b/lib/DriverTool/swift_cache_tool_main.cpp
@@ -194,7 +194,7 @@ class SwiftCacheToolInvocation {
                              MainExecutablePath))
       return true;
 
-    if (!Invocation.getFrontendOptions().EnableCAS) {
+    if (!Invocation.getFrontendOptions().EnableCaching) {
       llvm::errs() << "Requested command-line arguments do not enable CAS\n";
       return true;
     }
diff --git a/lib/Frontend/ArgsToFrontendOptionsConverter.cpp b/lib/Frontend/ArgsToFrontendOptionsConverter.cpp
index b7ff8bb6fb712..0ab9e9fae8cf7 100644
--- a/lib/Frontend/ArgsToFrontendOptionsConverter.cpp
+++ b/lib/Frontend/ArgsToFrontendOptionsConverter.cpp
@@ -351,13 +351,23 @@ bool ArgsToFrontendOptionsConverter::convert(
     Opts.BlocklistConfigFilePaths.push_back(A);
   }
 
-  Opts.EnableCAS = Args.hasArg(OPT_enable_cas);
-  Opts.CASPath =
+  Opts.EnableCaching = Args.hasArg(OPT_cache_compile_job);
+  Opts.EnableCachingRemarks = Args.hasArg(OPT_cache_remarks);
+  Opts.CacheSkipReplay = Args.hasArg(OPT_cache_disable_replay);
+  Opts.CASOpts.CASPath =
       Args.getLastArgValue(OPT_cas_path, llvm::cas::getDefaultOnDiskCASPath());
+  Opts.CASOpts.PluginPath = Args.getLastArgValue(OPT_cas_plugin_path);
+  for (StringRef Opt : Args.getAllArgValues(OPT_cas_plugin_option)) {
+    StringRef Name, Value;
+    std::tie(Name, Value) = Opt.split('=');
+    Opts.CASOpts.PluginOptions.emplace_back(std::string(Name),
+                                            std::string(Value));
+  }
+
   Opts.CASFSRootIDs = Args.getAllArgValues(OPT_cas_fs);
   Opts.ClangIncludeTrees = Args.getAllArgValues(OPT_clang_include_tree_root);
 
-  if (Opts.EnableCAS && Opts.CASFSRootIDs.empty() &&
+  if (Opts.EnableCaching && Opts.CASFSRootIDs.empty() &&
       Opts.ClangIncludeTrees.empty() &&
       FrontendOptions::supportCompilationCaching(Opts.RequestedAction)) {
     if (!Args.hasArg(OPT_allow_unstable_cache_key_for_testing)) {
diff --git a/lib/Frontend/CachedDiagnostics.cpp b/lib/Frontend/CachedDiagnostics.cpp
index 5c72b72f60a68..bf6c76946dd4e 100644
--- a/lib/Frontend/CachedDiagnostics.cpp
+++ b/lib/Frontend/CachedDiagnostics.cpp
@@ -728,7 +728,7 @@ CachingDiagnosticsProcessor::CachingDiagnosticsProcessor(
     : Impl(*new Implementation(Instance)) {
   Impl.serializedOutputCallback = [&](StringRef Output) {
     LLVM_DEBUG(llvm::dbgs() << Output << "\n";);
-    if (!Instance.getInvocation().getFrontendOptions().EnableCAS)
+    if (!Instance.getInvocation().getFrontendOptions().EnableCaching)
       return false;
 
     // compress the YAML file.
diff --git a/lib/Frontend/CachingUtils.cpp b/lib/Frontend/CachingUtils.cpp
index cb6435d887120..07618817765b9 100644
--- a/lib/Frontend/CachingUtils.cpp
+++ b/lib/Frontend/CachingUtils.cpp
@@ -142,7 +142,7 @@ createSwiftCachingOutputBackend(
 bool replayCachedCompilerOutputs(
     ObjectStore &CAS, ActionCache &Cache, ObjectRef BaseKey,
     DiagnosticEngine &Diag, const FrontendInputsAndOutputs &InputsAndOutputs,
-    CachingDiagnosticsProcessor &CDP) {
+    CachingDiagnosticsProcessor &CDP, bool CacheRemarks) {
   clang::cas::CompileJobResultSchema Schema(CAS);
   bool CanReplayAllOutput = true;
   struct OutputEntry {
@@ -173,8 +173,9 @@ bool replayCachedCompilerOutputs(
       return None;
     }
     if (!*Lookup) {
-      Diag.diagnose(SourceLoc(), diag::output_cache_miss, OutputPath,
-                    OutputKeyID.toString());
+      if (CacheRemarks)
+        Diag.diagnose(SourceLoc(), diag::output_cache_miss, OutputPath,
+                      OutputKeyID.toString());
       return None;
     }
     auto OutputRef = CAS.getReference(**Lookup);
@@ -261,7 +262,8 @@ bool replayCachedCompilerOutputs(
                     toString(std::move(E)));
       continue;
     }
-    Diag.diagnose(SourceLoc(), diag::replay_output, Output.Path, Output.Key);
+    if (CacheRemarks)
+      Diag.diagnose(SourceLoc(), diag::replay_output, Output.Path, Output.Key);
   }
 
   return true;
diff --git a/lib/Frontend/CompilerInvocation.cpp b/lib/Frontend/CompilerInvocation.cpp
index c3182dffc347a..4769d5a2a7946 100644
--- a/lib/Frontend/CompilerInvocation.cpp
+++ b/lib/Frontend/CompilerInvocation.cpp
@@ -1505,8 +1505,8 @@ static bool ParseClangImporterArgs(ClangImporterOptions &Opts,
 
   // Forward the FrontendOptions to clang importer option so it can be
   // accessed when creating clang module compilation invocation.
-  if (FrontendOpts.EnableCAS)
-    Opts.CASPath = FrontendOpts.CASPath;
+  if (FrontendOpts.EnableCaching)
+    Opts.CASOpts = FrontendOpts.CASOpts;
 
   return false;
 }
diff --git a/lib/Frontend/Frontend.cpp b/lib/Frontend/Frontend.cpp
index a1cfd21092870..4a109f7493d60 100644
--- a/lib/Frontend/Frontend.cpp
+++ b/lib/Frontend/Frontend.cpp
@@ -403,17 +403,16 @@ void CompilerInstance::setupDependencyTrackerIfNeeded() {
 
 bool CompilerInstance::setupCASIfNeeded(ArrayRef<const char *> Args) {
   const auto &Opts = getInvocation().getFrontendOptions();
-  if (!Opts.EnableCAS)
+  if (!Opts.EnableCaching)
     return false;
 
-  auto MaybeCache = llvm::cas::createOnDiskUnifiedCASDatabases(Opts.CASPath);
-  if (!MaybeCache) {
-    Diagnostics.diagnose(SourceLoc(), diag::error_create_cas, Opts.CASPath,
-                         toString(MaybeCache.takeError()));
+  auto MaybeDB= Opts.CASOpts.getOrCreateDatabases();
+  if (!MaybeDB) {
+    Diagnostics.diagnose(SourceLoc(), diag::error_cas,
+                         toString(MaybeDB.takeError()));
     return true;
   }
-  CAS = std::move(MaybeCache->first);
-  ResultCache = std::move(MaybeCache->second);
+  std::tie(CAS, ResultCache) = *MaybeDB;
 
   // create baseline key.
   auto BaseKey = createCompileJobBaseCacheKey(*CAS, Args);
@@ -521,7 +520,7 @@ bool CompilerInstance::setup(const CompilerInvocation &Invoke,
 }
 
 bool CompilerInstance::setUpVirtualFileSystemOverlays() {
-  if (Invocation.getFrontendOptions().EnableCAS &&
+  if (Invocation.getFrontendOptions().EnableCaching &&
       (!Invocation.getFrontendOptions().CASFSRootIDs.empty() ||
        !Invocation.getFrontendOptions().ClangIncludeTrees.empty())) {
     // Set up CASFS as BaseFS.
@@ -538,7 +537,7 @@ bool CompilerInstance::setUpVirtualFileSystemOverlays() {
 
   // If we have a bridging header cache key, try load it now and overlay it.
   if (!Invocation.getClangImporterOptions().BridgingHeaderPCHCacheKey.empty() &&
-      Invocation.getFrontendOptions().EnableCAS) {
+      Invocation.getFrontendOptions().EnableCaching) {
     auto loadedBridgingBuffer = loadCachedCompileResultFromCacheKey(
         getObjectStore(), getActionCache(), Diagnostics,
         Invocation.getClangImporterOptions().BridgingHeaderPCHCacheKey,
@@ -682,7 +681,7 @@ bool CompilerInstance::setUpModuleLoaders() {
   if (ExplicitModuleBuild ||
       !Invocation.getSearchPathOptions().ExplicitSwiftModuleMap.empty() ||
       !Invocation.getSearchPathOptions().ExplicitSwiftModuleInputs.empty()) {
-    if (Invocation.getFrontendOptions().EnableCAS)
+    if (Invocation.getFrontendOptions().EnableCaching)
       ESML = ExplicitCASModuleLoader::create(
           *Context, getObjectStore(), getActionCache(), getDependencyTracker(),
           MLM, Invocation.getSearchPathOptions().ExplicitSwiftModuleMap,
@@ -1107,7 +1106,7 @@ bool CompilerInstance::canImportCxxShim() const {
 }
 
 bool CompilerInstance::supportCaching() const {
-  if (!Invocation.getFrontendOptions().EnableCAS)
+  if (!Invocation.getFrontendOptions().EnableCaching)
     return false;
 
   return FrontendOptions::supportCompilationCaching(
diff --git a/lib/Frontend/ModuleInterfaceLoader.cpp b/lib/Frontend/ModuleInterfaceLoader.cpp
index 5aaaf9d90de1c..261ba5a4e3ace 100644
--- a/lib/Frontend/ModuleInterfaceLoader.cpp
+++ b/lib/Frontend/ModuleInterfaceLoader.cpp
@@ -39,6 +39,7 @@
 #include "llvm/ADT/Hashing.h"
 #include "llvm/ADT/STLExtras.h"
 #include "llvm/ADT/StringExtras.h"
+#include "llvm/ADT/Twine.h"
 #include "llvm/CAS/ActionCache.h"
 #include "llvm/CAS/ObjectStore.h"
 #include "llvm/Support/CommandLine.h"
@@ -1181,7 +1182,7 @@ std::error_code ModuleInterfaceLoader::findModuleFilesInDirectory(
 
   // First check to see if the .swiftinterface exists at all. Bail if not.
   auto &fs = *Ctx.SourceMgr.getFileSystem();
-  std::string InPath = BaseName.findInterfacePath(fs).getValueOr("");
+  std::string InPath = BaseName.findInterfacePath(fs).value_or("");
   if (InPath.empty()) {
     if (fs.exists(ModPath)) {
       LLVM_DEBUG(llvm::dbgs()
@@ -1600,12 +1601,23 @@ void InterfaceSubContextDelegateImpl::inheritOptionsForBuildingInterface(
     GenericArgs.push_back(clangImporterOpts.BuildSessionFilePath);
   }
 
-  if (!clangImporterOpts.CASPath.empty()) {
-    genericSubInvocation.getClangImporterOptions().CASPath =
-        clangImporterOpts.CASPath;
+  if (clangImporterOpts.CASOpts) {
+    genericSubInvocation.getClangImporterOptions().CASOpts =
+        clangImporterOpts.CASOpts;
     GenericArgs.push_back("-enable-cas");
-    GenericArgs.push_back("-cas-path");
-    GenericArgs.push_back(clangImporterOpts.CASPath);
+    if (!clangImporterOpts.CASOpts->CASPath.empty()) {
+      GenericArgs.push_back("-cas-path");
+      GenericArgs.push_back(clangImporterOpts.CASOpts->CASPath);
+    }
+    if (!clangImporterOpts.CASOpts->PluginPath.empty()) {
+      GenericArgs.push_back("-cas-plugin-path");
+      GenericArgs.push_back(clangImporterOpts.CASOpts->PluginPath);
+      for (auto Opt : clangImporterOpts.CASOpts->PluginOptions) {
+        GenericArgs.push_back("-cas-plugin-option");
+        std::string pair = (llvm::Twine(Opt.first) + "=" + Opt.second).str();
+        GenericArgs.push_back(ArgSaver.save(pair));
+      }
+    }
   }
 
   if (clangImporterOpts.UseClangIncludeTree) {
@@ -1702,7 +1714,7 @@ InterfaceSubContextDelegateImpl::InterfaceSubContextDelegateImpl(
   // required by sourcekitd.
   subClangImporterOpts.DetailedPreprocessingRecord =
     clangImporterOpts.DetailedPreprocessingRecord;
-  subClangImporterOpts.CASPath = clangImporterOpts.CASPath;
+  subClangImporterOpts.CASOpts = clangImporterOpts.CASOpts;
 
   // If the compiler has been asked to be strict with ensuring downstream dependencies
   // get the parent invocation's context, or this is an Explicit build, inherit the
diff --git a/lib/FrontendTool/FrontendTool.cpp b/lib/FrontendTool/FrontendTool.cpp
index 65aa3f851a65d..8d183e89e718a 100644
--- a/lib/FrontendTool/FrontendTool.cpp
+++ b/lib/FrontendTool/FrontendTool.cpp
@@ -1394,7 +1394,8 @@ static bool performAction(CompilerInstance &Instance,
 /// Return true if all the outputs are fetched from cache. Otherwise, return
 /// false and will not replay any output.
 static bool tryReplayCompilerResults(CompilerInstance &Instance) {
-  if (!Instance.supportCaching())
+  if (!Instance.supportCaching() ||
+      Instance.getInvocation().getFrontendOptions().CacheSkipReplay)
     return false;
 
   assert(Instance.getCompilerBaseKey() &&
@@ -1409,7 +1410,8 @@ static bool tryReplayCompilerResults(CompilerInstance &Instance) {
   bool replayed = replayCachedCompilerOutputs(
       Instance.getObjectStore(), Instance.getActionCache(),
       *Instance.getCompilerBaseKey(), Instance.getDiags(),
-      Instance.getInvocation().getFrontendOptions().InputsAndOutputs, *CDP);
+      Instance.getInvocation().getFrontendOptions().InputsAndOutputs, *CDP,
+      Instance.getInvocation().getFrontendOptions().EnableCachingRemarks);
 
   // If we didn't replay successfully, re-start capture.
   if (!replayed)
diff --git a/test/CAS/binary_module_deps.swift b/test/CAS/binary_module_deps.swift
index e59a88e17c09f..abd5db0be8166 100644
--- a/test/CAS/binary_module_deps.swift
+++ b/test/CAS/binary_module_deps.swift
@@ -6,7 +6,7 @@
 
 // RUN: %target-swift-frontend -emit-module -module-cache-path %t/clang-module-cache %S/../ScanDependencies/Inputs/Swift/E.swiftinterface -o %t/E.swiftmodule -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -swift-version 4
 // RUN: %target-swift-frontend -emit-module -module-cache-path %t/clang-module-cache %S/../ScanDependencies/Inputs/Swift/A.swiftinterface -o %t/A.swiftmodule -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -swift-version 4
-// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %t -swift-version 4 -enable-cas -cas-path %t/cas
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %t -swift-version 4 -cache-compile-job -cas-path %t/cas
 // RUN: %FileCheck %s -DTEMP=%t < %t/deps.json
 
 /// Test binary module key: binary module key is the CASID of itself.
diff --git a/test/CAS/cache_key_compute.swift b/test/CAS/cache_key_compute.swift
index 903ee22a3fb8e..3f66107f3905f 100644
--- a/test/CAS/cache_key_compute.swift
+++ b/test/CAS/cache_key_compute.swift
@@ -10,16 +10,16 @@
 
 /// Check few working cases.
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-base-key -- \
-// RUN:   %target-swift-frontend -enable-cas %s -c -allow-unstable-cache-key-for-testing > %t1.casid
+// RUN:   %target-swift-frontend -cache-compile-job %s -c -allow-unstable-cache-key-for-testing > %t1.casid
 /// A different CAS doesn't affect base key.
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-base-key -- \
-// RUN:   %target-swift-frontend -enable-cas %s -c -allow-unstable-cache-key-for-testing -cas-path %t > %t2.casid
+// RUN:   %target-swift-frontend -cache-compile-job %s -c -allow-unstable-cache-key-for-testing -cas-path %t > %t2.casid
 /// Output path doesn't affect base key.
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-base-key -- \
-// RUN:   %target-swift-frontend -enable-cas %s -c -allow-unstable-cache-key-for-testing -o %t/test.o > %t3.casid
+// RUN:   %target-swift-frontend -cache-compile-job %s -c -allow-unstable-cache-key-for-testing -o %t/test.o > %t3.casid
 /// Add -D will change.
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-base-key -- \
-// RUN:   %target-swift-frontend -enable-cas %s -c -allow-unstable-cache-key-for-testing -DTEST > %t4.casid
+// RUN:   %target-swift-frontend -cache-compile-job %s -c -allow-unstable-cache-key-for-testing -DTEST > %t4.casid
 
 // RUN: diff %t1.casid %t2.casid
 // RUN: diff %t1.casid %t3.casid
@@ -31,17 +31,17 @@
 // RUN: cp %s %t/temp.swift
 // RUN: echo "%t/temp.swift" > %t/filelist-3
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-base-key -- \
-// RUN:   %target-swift-frontend -enable-cas -filelist %t/filelist-1 -c -allow-unstable-cache-key-for-testing > %t5.casid
+// RUN:   %target-swift-frontend -cache-compile-job -filelist %t/filelist-1 -c -allow-unstable-cache-key-for-testing > %t5.casid
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-base-key -- \
-// RUN:   %target-swift-frontend -enable-cas -filelist %t/filelist-2 -c -allow-unstable-cache-key-for-testing > %t6.casid
+// RUN:   %target-swift-frontend -cache-compile-job -filelist %t/filelist-2 -c -allow-unstable-cache-key-for-testing > %t6.casid
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-base-key -- \
-// RUN:   %target-swift-frontend -enable-cas -filelist %t/filelist-3 -c -allow-unstable-cache-key-for-testing > %t7.casid
+// RUN:   %target-swift-frontend -cache-compile-job -filelist %t/filelist-3 -c -allow-unstable-cache-key-for-testing > %t7.casid
 // RUN: diff %t5.casid %t6.casid
 // RUN: not diff %t5.casid %t7.casid
 
 /// Test output keys.
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- \
-// RUN:   %target-swift-frontend -enable-cas %s -emit-module -c -emit-dependencies \
+// RUN:   %target-swift-frontend -cache-compile-job %s -emit-module -c -emit-dependencies \
 // RUN:   -emit-tbd -emit-tbd-path %t/test.tbd -o %t/test.o -allow-unstable-cache-key-for-testing | %FileCheck %s
 
 // CHECK: test.o
diff --git a/test/CAS/cache_replay.swift b/test/CAS/cache_replay.swift
index 8a73dff234591..89a275f0fcef6 100644
--- a/test/CAS/cache_replay.swift
+++ b/test/CAS/cache_replay.swift
@@ -2,18 +2,23 @@
 
 /// Run the command first time, expect cache miss.
 /// FIXME: This command doesn't use `-cas-fs` so it is not a good cache entry. It is currently allowed so it is easier to write tests.
-// RUN: %target-swift-frontend -enable-cas %s -emit-module -emit-module-path %t/Test.swiftmodule -c -emit-dependencies \
+// RUN: %target-swift-frontend -cache-compile-job -cache-remarks %s -emit-module -emit-module-path %t/Test.swiftmodule -c -emit-dependencies \
 // RUN:  -module-name Test -o %t/test.o -cas-path %t/cas -allow-unstable-cache-key-for-testing 2>&1 | %FileCheck --check-prefix=CACHE-MISS %s
 
 /// Expect cache hit for second time.
-// RUN: %target-swift-frontend -enable-cas %s -emit-module -emit-module-path %t/Test.swiftmodule -c -emit-dependencies \
+// RUN: %target-swift-frontend -cache-compile-job -cache-remarks %s -emit-module -emit-module-path %t/Test.swiftmodule -c -emit-dependencies \
 // RUN:  -module-name Test -o %t/test.o -cas-path %t/cas -allow-unstable-cache-key-for-testing 2>&1 | %FileCheck --check-prefix=CACHE-HIT %s
 
 /// Expect cache hit a subset of outputs.
-// RUN: %target-swift-frontend -enable-cas %s -emit-module -emit-module-path %t/Test.swiftmodule -c \
+// RUN: %target-swift-frontend -cache-compile-job -cache-remarks %s -emit-module -emit-module-path %t/Test.swiftmodule -c \
 // RUN:  -module-name Test -o %t/test.o -cas-path %t/cas -allow-unstable-cache-key-for-testing 2>&1 | %FileCheck --check-prefix=CACHE-HIT %s
 
+/// Skip cache
+// RUN: %target-swift-frontend -cache-compile-job -cache-remarks -cache-disable-replay %s -emit-module -emit-module-path %t/Test.swiftmodule -c \
+// RUN:  -module-name Test -o %t/test.o -cas-path %t/cas -allow-unstable-cache-key-for-testing 2>&1 | %FileCheck --allow-empty --check-prefix=SKIP-CACHE %s
+
 // CACHE-MISS: remark: cache miss output file
 // CACHE-HIT: remark: replay output file
+// SKIP-CACHE-NOT: remark:
 
 func testFunc() {}
diff --git a/test/CAS/cached_diagnostics.swift b/test/CAS/cached_diagnostics.swift
index 19cc2c1d0aaf9..7fc7bec149ebd 100644
--- a/test/CAS/cached_diagnostics.swift
+++ b/test/CAS/cached_diagnostics.swift
@@ -1,10 +1,10 @@
 // RUN: %empty-directory(%t)
 
-// RUN: %target-swift-frontend -c -enable-cas -cas-path %t/cas -allow-unstable-cache-key-for-testing %s \
+// RUN: %target-swift-frontend -c -cache-compile-job -cas-path %t/cas -allow-unstable-cache-key-for-testing %s \
 // RUN:   -import-objc-header %S/Inputs/objc.h -emit-module -emit-module-path %t/test.swiftmodule 2>&1 | %FileCheck %s
-// RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- %target-swift-frontend -c -enable-cas -cas-path %t/cas -allow-unstable-cache-key-for-testing %s \
+// RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- %target-swift-frontend -c -cache-compile-job -cas-path %t/cas -allow-unstable-cache-key-for-testing %s \
 // RUN:   -import-objc-header %S/Inputs/objc.h -emit-module -emit-module-path %t/test.swiftmodule > %t/cache_key.json
-// RUN: %cache-tool -cas-path %t/cas -cache-tool-action render-diags %t/cache_key.json -- %target-swift-frontend -c -enable-cas -cas-path %t/cas -allow-unstable-cache-key-for-testing %s \
+// RUN: %cache-tool -cas-path %t/cas -cache-tool-action render-diags %t/cache_key.json -- %target-swift-frontend -c -cache-compile-job -cas-path %t/cas -allow-unstable-cache-key-for-testing %s \
 // RUN:   -import-objc-header %S/Inputs/objc.h -emit-module -emit-module-path %t/test.swiftmodule 2>&1 | %FileCheck %s
 
 #warning("this is a warning")  // expected-warning {{this is a warning}}
@@ -13,7 +13,7 @@
 // CHECK: warning: this is a warning
 
 /// Check other DiagnosticConsumers.
-// RUN: %target-swift-frontend -c -enable-cas -cas-path %t/cas -allow-unstable-cache-key-for-testing %s \
+// RUN: %target-swift-frontend -c -cache-compile-job -cas-path %t/cas -allow-unstable-cache-key-for-testing %s \
 // RUN:   -typecheck -serialize-diagnostics -serialize-diagnostics-path %t/test.diag -verify
 // RUN: %FileCheck %s -check-prefix CHECK-SERIALIZED <%t/test.diag
 
diff --git a/test/CAS/cas-explicit-module-map.swift b/test/CAS/cas-explicit-module-map.swift
index fec0dd188d2ec..26e981528616b 100644
--- a/test/CAS/cas-explicit-module-map.swift
+++ b/test/CAS/cas-explicit-module-map.swift
@@ -5,7 +5,7 @@
 // RUN: %target-swift-emit-pcm -module-cache-path %t/clang-module-cache -module-name _SwiftConcurrencyShims %swift-lib-dir/swift/shims/module.modulemap -o %t/_SwiftConcurrencyShims.pcm
 // RUN: %target-swift-frontend -emit-module -module-cache-path %t/clang-module-cache %t/A.swift -o %t/A.swiftmodule -swift-version 5
 // RUN: %target-swift-frontend -emit-module -module-cache-path %t/clang-module-cache %t/B.swift -o %t/B.swiftmodule -I %t -swift-version 5
-// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %t/Test.swift -o %t/deps.json -I %t -swift-version 5 -enable-cas -cas-path %t/cas
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %t/Test.swift -o %t/deps.json -I %t -swift-version 5 -cache-compile-job -cas-path %t/cas
 
 // RUN: %S/Inputs/SwiftDepsExtractor.py %t/deps.json swiftPrebuiltExternal:A moduleCacheKey | tr -d '\n' > %t/A.key
 // RUN: %S/Inputs/SwiftDepsExtractor.py %t/deps.json swiftPrebuiltExternal:B moduleCacheKey | tr -d '\n' > %t/B.key
@@ -107,7 +107,7 @@
 
 // RUN: llvm-cas --cas %t/cas --make-blob --data %t/map.json > %t/map.casid
 
-// RUN: %target-swift-frontend -emit-module -emit-module-path %t/Foo.swiftmodule -disable-implicit-swift-modules -module-cache-path %t.module-cache -explicit-swift-module-map-file @%t/map.casid -Rmodule-loading -Xcc -Rmodule-import %s -enable-cas -cas-path %t/cas -allow-unstable-cache-key-for-testing 2>&1 | %FileCheck %s
+// RUN: %target-swift-frontend -emit-module -emit-module-path %t/Foo.swiftmodule -disable-implicit-swift-modules -module-cache-path %t.module-cache -explicit-swift-module-map-file @%t/map.casid -Rmodule-loading -Xcc -Rmodule-import %s -cache-compile-job -cas-path %t/cas -allow-unstable-cache-key-for-testing 2>&1 | %FileCheck %s
 
 // CHECK-DAG: loaded module 'A'
 // CHECK-DAG: loaded module 'B'
diff --git a/test/CAS/cas_fs.swift b/test/CAS/cas_fs.swift
index 8020d2963abee..8ed83237d0e9a 100644
--- a/test/CAS/cas_fs.swift
+++ b/test/CAS/cas_fs.swift
@@ -3,24 +3,24 @@
 // RUN: mkdir -p %t/cas
 
 // RUN: llvm-cas --cas %t/cas --ingest --data %t/empty > %t/empty.casid
-// RUN: not %target-swift-frontend -typecheck -enable-cas -cas-fs @%t/empty.casid -cas-path %t/cas %s 2>&1 | %FileCheck %s --check-prefix NO-INPUTS
+// RUN: not %target-swift-frontend -typecheck -cache-compile-job -cas-fs @%t/empty.casid -cas-path %t/cas %s 2>&1 | %FileCheck %s --check-prefix NO-INPUTS
 // NO-INPUTS: error: error opening input file
 
 // RUN: llvm-cas --cas %t/cas --ingest --data %s > %t/source.casid
-// RUN: not %target-swift-frontend -typecheck -enable-cas -cas-fs @%t/source.casid -cas-path %t/cas %s 2>&1 | %FileCheck %s --check-prefix NO-RESOURCES
+// RUN: not %target-swift-frontend -typecheck -cache-compile-job -cas-fs @%t/source.casid -cas-path %t/cas %s 2>&1 | %FileCheck %s --check-prefix NO-RESOURCES
 // NO-RESOURCES: error: unable to load standard library
 
 /// Ingest the resource directory to satisfy the file system requirement. Also switch CWD to resource dir.
 // RUN: llvm-cas --cas %t/cas --merge @%t/source.casid %test-resource-dir > %t/full.casid
 // RUN: cd %test-resource-dir
-// RUN: %target-swift-frontend -typecheck -enable-cas -cas-fs @%t/full.casid -cas-path %t/cas %s
+// RUN: %target-swift-frontend -typecheck -cache-compile-job -cas-fs @%t/full.casid -cas-path %t/cas %s
 
 /// Try clang importer.
-// RUN: not %target-swift-frontend -typecheck -enable-cas -cas-fs @%t/full.casid -cas-path %t/cas %s -import-objc-header %S/Inputs/objc.h 2>&1 | %FileCheck %s --check-prefix NO-BRIDGING-HEADER
+// RUN: not %target-swift-frontend -typecheck -cache-compile-job -cas-fs @%t/full.casid -cas-path %t/cas %s -import-objc-header %S/Inputs/objc.h 2>&1 | %FileCheck %s --check-prefix NO-BRIDGING-HEADER
 // NO-BRIDGING-HEADER: error: bridging header
 
 // RUN: llvm-cas --cas %t/cas --merge @%t/full.casid %S/Inputs/objc.h > %t/bridging_header.casid
-// RUN: %target-swift-frontend -typecheck -enable-cas -cas-fs @%t/bridging_header.casid -cas-path %t/cas %s -import-objc-header %S/Inputs/objc.h
+// RUN: %target-swift-frontend -typecheck -cache-compile-job -cas-fs @%t/bridging_header.casid -cas-path %t/cas %s -import-objc-header %S/Inputs/objc.h
 
 /// Clean the CAS to save space.
 // RUN: %empty-directory(%t)
diff --git a/test/CAS/cas_output_backend.swift b/test/CAS/cas_output_backend.swift
index 4a949f5bb8d4a..8ab26067e6360 100644
--- a/test/CAS/cas_output_backend.swift
+++ b/test/CAS/cas_output_backend.swift
@@ -1,12 +1,12 @@
 // RUN: %empty-directory(%t)
 // RUN: mkdir -p %t/cas
 
-// RUN: not %target-swift-frontend -c -enable-cas -cas-path %t/cas %s -o %t/test.o 2>&1 | %FileCheck %s --check-prefix=NO-CASFS
+// RUN: not %target-swift-frontend -c -cache-compile-job -cas-path %t/cas %s -o %t/test.o 2>&1 | %FileCheck %s --check-prefix=NO-CASFS
 // NO-CASFS: caching is enabled without -cas-fs option
 
-// RUN: %target-swift-frontend -c -enable-cas -cas-path %t/cas %s -o %t/test.o -allow-unstable-cache-key-for-testing
+// RUN: %target-swift-frontend -c -cache-compile-job -cas-path %t/cas %s -o %t/test.o -allow-unstable-cache-key-for-testing
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- \
-// RUN:   %target-swift-frontend -c -enable-cas -cas-path %t/cas %s -o %t/test.o -allow-unstable-cache-key-for-testing > %t/cache_key.json
+// RUN:   %target-swift-frontend -c -cache-compile-job -cas-path %t/cas %s -o %t/test.o -allow-unstable-cache-key-for-testing > %t/cache_key.json
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action validate-outputs %t/cache_key.json
 
 /// make sure validate fails if the cas is cleared.
diff --git a/test/CAS/loc-directive-diagnostics.swift b/test/CAS/loc-directive-diagnostics.swift
index 6ca39f3170870..518845e14512f 100644
--- a/test/CAS/loc-directive-diagnostics.swift
+++ b/test/CAS/loc-directive-diagnostics.swift
@@ -1,11 +1,11 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend -emit-module -emit-module-path %t/test.module \
-// RUN:   -enable-cas -cas-path %t/cas -allow-unstable-cache-key-for-testing %s 2>&1 | %FileCheck %s
+// RUN:   -cache-compile-job -cas-path %t/cas -allow-unstable-cache-key-for-testing %s 2>&1 | %FileCheck %s
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action print-output-keys -- \
-// RUN:   %target-swift-frontend -emit-module -emit-module-path %t/test.module -enable-cas -cas-path %t/cas \
+// RUN:   %target-swift-frontend -emit-module -emit-module-path %t/test.module -cache-compile-job -cas-path %t/cas \
 // RUN:   -allow-unstable-cache-key-for-testing %s > %t/cache_key.json
 // RUN: %cache-tool -cas-path %t/cas -cache-tool-action render-diags %t/cache_key.json --  \
-// RUN:   %target-swift-frontend -emit-module -emit-module-path %t/test.module -enable-cas -cas-path %t/cas \
+// RUN:   %target-swift-frontend -emit-module -emit-module-path %t/test.module -cache-compile-job -cas-path %t/cas \
 // RUN:   -allow-unstable-cache-key-for-testing %s 2>&1 | %FileCheck %s
 
 #sourceLocation(file: "anything.swift", line: 1)
diff --git a/test/CAS/module_deps.swift b/test/CAS/module_deps.swift
index 4d646ad049415..e7bbdb3979719 100644
--- a/test/CAS/module_deps.swift
+++ b/test/CAS/module_deps.swift
@@ -4,7 +4,7 @@
 // RUN: mkdir -p %t/clang-module-cache
 // RUN: mkdir -p %t/cas
 
-// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -emit-dependencies -emit-dependencies-path %t/deps.d -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -enable-cas -cas-path %t/cas
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -emit-dependencies -emit-dependencies-path %t/deps.d -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -cache-compile-job -cas-path %t/cas
 // Check the contents of the JSON output
 // RUN: %FileCheck -check-prefix CHECK -check-prefix CHECK_NO_CLANG_TARGET %s < %t/deps.json
 
@@ -14,11 +14,11 @@
 // Check the make-style dependencies file
 // RUN: %FileCheck %s -check-prefix CHECK-MAKE-DEPS < %t/deps.d
 
-// RUN: %target-swift-frontend -scan-dependencies -test-dependency-scan-cache-serialization -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -enable-cas -cas-path %t/cas
+// RUN: %target-swift-frontend -scan-dependencies -test-dependency-scan-cache-serialization -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -cache-compile-job -cas-path %t/cas
 // RUN: %FileCheck -check-prefix CHECK -check-prefix CHECK_NO_CLANG_TARGET %s < %t/deps.json
 
 // Ensure that scanning with `-clang-target` makes sure that Swift modules' respective PCM-dependency-build-argument sets do not contain target triples.
-// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %s -o %t/deps_clang_target.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -clang-target %target-cpu-apple-macosx10.14 -enable-cas -cas-path %t/cas
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %s -o %t/deps_clang_target.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -clang-target %target-cpu-apple-macosx10.14 -cache-compile-job -cas-path %t/cas
 // Check the contents of the JSON output
 // RUN: %FileCheck -check-prefix CHECK_CLANG_TARGET %s < %t/deps_clang_target.json
 
diff --git a/test/CAS/module_deps_include_tree.swift b/test/CAS/module_deps_include_tree.swift
index 85c113e361bd2..75231ed9e3352 100644
--- a/test/CAS/module_deps_include_tree.swift
+++ b/test/CAS/module_deps_include_tree.swift
@@ -4,7 +4,7 @@
 // RUN: mkdir -p %t/clang-module-cache
 // RUN: mkdir -p %t/cas
 
-// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -emit-dependencies -emit-dependencies-path %t/deps.d -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -enable-cas -cas-path %t/cas -clang-include-tree
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -emit-dependencies -emit-dependencies-path %t/deps.d -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -cache-compile-job -cas-path %t/cas -clang-include-tree
 // Check the contents of the JSON output
 // RUN: %FileCheck -check-prefix CHECK -check-prefix CHECK_NO_CLANG_TARGET %s < %t/deps.json
 
@@ -14,11 +14,11 @@
 // Check the make-style dependencies file
 // RUN: %FileCheck %s -check-prefix CHECK-MAKE-DEPS < %t/deps.d
 
-// RUN: %target-swift-frontend -scan-dependencies -test-dependency-scan-cache-serialization -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -enable-cas -cas-path %t/cas -clang-include-tree
+// RUN: %target-swift-frontend -scan-dependencies -test-dependency-scan-cache-serialization -module-cache-path %t/clang-module-cache %s -o %t/deps.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -cache-compile-job -cas-path %t/cas -clang-include-tree
 // RUN: %FileCheck -check-prefix CHECK -check-prefix CHECK_NO_CLANG_TARGET %s < %t/deps.json
 
 // Ensure that scanning with `-clang-target` makes sure that Swift modules' respective PCM-dependency-build-argument sets do not contain target triples.
-// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %s -o %t/deps_clang_target.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -clang-target %target-cpu-apple-macosx10.14 -enable-cas -cas-path %t/cas -clang-include-tree
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %s -o %t/deps_clang_target.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h -swift-version 4 -clang-target %target-cpu-apple-macosx10.14 -cache-compile-job -cas-path %t/cas -clang-include-tree
 // Check the contents of the JSON output
 // RUN: %FileCheck -check-prefix CHECK_CLANG_TARGET %s < %t/deps_clang_target.json
 
diff --git a/test/CAS/plugin_cas.swift b/test/CAS/plugin_cas.swift
new file mode 100644
index 0000000000000..5ff985706670e
--- /dev/null
+++ b/test/CAS/plugin_cas.swift
@@ -0,0 +1,186 @@
+// REQUIRES: objc_interop
+
+// RUN: %empty-directory(%t)
+// RUN: mkdir -p %t/clang-module-cache
+// RUN: mkdir -p %t/cas
+
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %s \
+// RUN:   -o %t/deps.json -I %S/../ScanDependencies/Inputs/CHeaders -I %S/../ScanDependencies/Inputs/Swift \
+// RUN:   -emit-dependencies -emit-dependencies-path %t/deps.d -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h \
+// RUN:   -swift-version 4 -cache-compile-job -clang-include-tree \
+// RUN:   -cas-path %t/cas \
+// RUN:   -cas-plugin-path %llvm_libs_dir/libCASPluginTest%llvm_plugin_ext \
+// RUN:   -cas-plugin-option first-prefix=myfirst- -cas-plugin-option second-prefix=mysecond- \
+// RUN:   -cas-plugin-option upstream-path=%t/cas-upstream
+// Check the contents of the JSON output
+// RUN: %FileCheck -check-prefix CHECK -check-prefix CHECK_NO_CLANG_TARGET %s < %t/deps.json
+
+// Check the contents of the JSON output
+// RUN: %FileCheck %s -check-prefix CHECK -check-prefix CHECK-NO-SEARCH-PATHS < %t/deps.json
+
+// Check the make-style dependencies file
+// RUN: %FileCheck %s -check-prefix CHECK-MAKE-DEPS < %t/deps.d
+
+// Ensure that scanning with `-clang-target` makes sure that Swift modules' respective PCM-dependency-build-argument sets do not contain target triples.
+// RUN: %target-swift-frontend -scan-dependencies -module-cache-path %t/clang-module-cache %s \
+// RUN:   -o %t/deps_clang_target.json -I %S/../ScanDependencies/Inputs/CHeaders \
+// RUN:   -I %S/../ScanDependencies/Inputs/Swift -import-objc-header %S/../ScanDependencies/Inputs/CHeaders/Bridging.h \
+// RUN:   -swift-version 4 -clang-target %target-cpu-apple-macosx10.14 -cache-compile-job -clang-include-tree \
+// RUN:   -cas-path %t/cas \
+// RUN:   -cas-plugin-path %llvm_libs_dir/libCASPluginTest%llvm_plugin_ext \
+// RUN:   -cas-plugin-option first-prefix=myfirst- -cas-plugin-option second-prefix=mysecond- \
+// RUN:   -cas-plugin-option upstream-path=%t/cas-upstream
+// Check the contents of the JSON output
+// RUN: %FileCheck -check-prefix CHECK_CLANG_TARGET %s < %t/deps_clang_target.json
+
+import C
+import E
+import G
+import SubE
+
+// CHECK: "mainModuleName": "deps"
+
+/// --------Main module
+// CHECK-LABEL: "modulePath": "deps.swiftmodule",
+// CHECK-NEXT: sourceFiles
+// CHECK-NEXT: plugin_cas.swift
+// CHECK-NEXT: ],
+// CHECK-NEXT: "directDependencies": [
+// CHECK-DAG:     "swift": "A"
+// CHECK-DAG:     "clang": "C"
+// CHECK-DAG:     "swift": "E"
+// CHECK-DAG:     "swift": "F"
+// CHECK-DAG:     "swift": "G"
+// CHECK-DAG:     "swift": "SubE"
+// CHECK-DAG:     "swift": "Swift"
+// CHECK-DAG:     "swift": "SwiftOnoneSupport"
+// CHECK-DAG:     "swift": "_Concurrency"
+// CHECK-DAG:     "swift": "_cross_import_E"
+// CHECK: ],
+
+// CHECK:      "extraPcmArgs": [
+// CHECK-NEXT:    "-Xcc",
+// CHECK-NEXT:    "-target",
+// CHECK-NEXT:    "-Xcc",
+// CHECK:         "-fapinotes-swift-version=4"
+// CHECK-NOT: "error: cannot open Swift placeholder dependency module map from"
+// CHECK: "bridgingHeader":
+// CHECK-NEXT: "path":
+// CHECK-SAME: Bridging.h
+
+// CHECK-NEXT: "sourceFiles":
+// CHECK-NEXT: Bridging.h
+// CHECK-NEXT: BridgingOther.h
+
+// CHECK: "moduleDependencies": [
+// CHECK-NEXT: "F"
+// CHECK-NEXT: ]
+
+/// --------Swift module A
+// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}A-{{.*}}.swiftmodule",
+
+// CHECK: directDependencies
+// CHECK-NEXT: {
+// CHECK-DAG:   "clang": "A"
+// CHECK-DAG:   "swift": "Swift"
+// CHECK-NEXT: },
+// CHECK: "details":
+// CHECK: "moduleCacheKey":
+
+/// --------Swift module F
+// CHECK:      "modulePath": "{{.*}}{{/|\\}}F-{{.*}}.swiftmodule",
+// CHECK-NEXT: "sourceFiles": [
+// CHECK-NEXT: ],
+// CHECK-NEXT: "directDependencies": [
+// CHECK-NEXT:   {
+// CHECK-DAG:     "clang": "F"
+// CHECK-DAG:     "swift": "Swift"
+// CHECK-DAG:     "swift": "SwiftOnoneSupport"
+// CHECK-NEXT:   }
+// CHECK-NEXT: ],
+// CHECK: "details":
+// CHECK: "moduleCacheKey":
+
+/// --------Swift module G
+// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}G-{{.*}}.swiftmodule"
+// CHECK: "directDependencies"
+// CHECK-NEXT: {
+// CHECK-DAG:   "clang": "G"
+// CHECK-DAG:   "swift": "Swift"
+// CHECK-DAG:   "swift": "SwiftOnoneSupport"
+// CHECK: ],
+// CHECK-NEXT: "details": {
+
+// CHECK: "contextHash": "{{.*}}",
+// CHECK: "commandLine": [
+// CHECK: "-compile-module-from-interface"
+// CHECK: "-target"
+// CHECK: "-module-name"
+// CHECK: "G"
+// CHECK: "-swift-version"
+// CHECK: "5"
+// CHECK: ],
+// CHECK_NO_CLANG_TARGET: "extraPcmArgs": [
+// CHECK_NO_CLANG_TARGET-NEXT:   "-Xcc",
+// CHECK_NO_CLANG_TARGET-NEXT:   "-target",
+// CHECK_CLANG_TARGET: "extraPcmArgs": [
+// CHECK_CLANG_TARGET-NEXT:   "-Xcc",
+// CHECK_CLANG_TARGET-NEXT:   "-fapinotes-swift-version={{.*}}"
+// CHECK_CLANG_TARGET-NEXT:   ]
+
+/// --------Swift module E
+// CHECK: "swift": "E"
+// CHECK-LABEL: modulePath": "{{.*}}{{/|\\}}E-{{.*}}.swiftmodule"
+// CHECK: "directDependencies"
+// CHECK-NEXT: {
+// CHECK-NEXT: "swift": "Swift"
+
+// CHECK: "moduleInterfacePath"
+// CHECK-SAME: E.swiftinterface
+
+/// --------Swift module Swift
+// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}Swift-{{.*}}.swiftmodule",
+
+// CHECK: directDependencies
+// CHECK-NEXT: {
+// CHECK-NEXT: "clang": "SwiftShims"
+
+/// --------Clang module SwiftShims
+// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}SwiftShims-{{.*}}.pcm",
+// CHECK: "contextHash": "[[SHIMS_CONTEXT:.*]]",
+// CHECK: "-o"
+// CHECK-NEXT: SwiftShims-{{.*}}[[SHIMS_CONTEXT]].pcm
+// CHECK-NO-SEARCH-PATHS-NOT: "-prebuilt-module-cache-path"
+
+/// --------Clang module C
+// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}C-{{.*}}.pcm",
+
+// CHECK: "sourceFiles": [
+// CHECK-DAG: module.modulemap
+// CHECK-DAG: C.h
+
+// CHECK: directDependencies
+// CHECK-NEXT: {
+// CHECK-NEXT: "clang": "B"
+
+// CHECK: "moduleMapPath"
+// CHECK-SAME: module.modulemap
+
+// CHECK: "contextHash"
+// CHECK-SAME: "{{.*}}"
+
+/// --------Clang module B
+// CHECK-LABEL: "modulePath": "{{.*}}{{/|\\}}B-{{.*}}.pcm",
+// CHECK: "contextHash": "[[B_CONTEXT:.*]]",
+// CHECK: "-o"
+// CHECK-NEXT: B-{{.*}}[[B_CONTEXT]].pcm
+
+// Check make-style dependencies
+// CHECK-MAKE-DEPS: plugin_cas.swift
+// CHECK-MAKE-DEPS-SAME: A.swiftinterface
+// CHECK-MAKE-DEPS-SAME: G.swiftinterface
+// CHECK-MAKE-DEPS-SAME: B.h
+// CHECK-MAKE-DEPS-SAME: F.h
+// CHECK-MAKE-DEPS-SAME: Bridging.h
+// CHECK-MAKE-DEPS-SAME: BridgingOther.h
+// CHECK-MAKE-DEPS-SAME: module.modulemap
diff --git a/test/CMakeLists.txt b/test/CMakeLists.txt
index cbbfdeffcbe74..b3a965e7c5eba 100644
--- a/test/CMakeLists.txt
+++ b/test/CMakeLists.txt
@@ -70,6 +70,7 @@ function(get_test_dependencies SDK result_var_name)
       arcmt-test
       c-arcmt-test
       c-index-test
+      CASPluginTest
       clang
       clang-cas-test
       count
diff --git a/test/lit.cfg b/test/lit.cfg
index d2cecb5015ddc..16e205d72db56 100644
--- a/test/lit.cfg
+++ b/test/lit.cfg
@@ -220,15 +220,15 @@ config.llvm_obj_root = getattr(config, 'llvm_obj_root', None)
 
 lto_flags = ""
 use_just_built_liblto = ""
+llvm_libs_dir = getattr(config, 'llvm_libs_dir', None)
+llvm_plugin_ext = getattr(config, 'llvm_plugin_ext', None)
 
 if platform.system() == 'OpenBSD':
-    llvm_libs_dir = getattr(config, 'llvm_libs_dir', None)
     if not llvm_libs_dir:
         lit_config.fatal('No LLVM libs dir set.')
     config.environment['LD_LIBRARY_PATH'] = llvm_libs_dir
 
 elif platform.system() == 'Darwin':
-    llvm_libs_dir = getattr(config, 'llvm_libs_dir', None)
     if not llvm_libs_dir:
         lit_config.fatal('No LLVM libs dir set.')
     lto_flags = "-Xlinker -lto_library -Xlinker %s/libLTO.dylib" % llvm_libs_dir
@@ -236,6 +236,8 @@ elif platform.system() == 'Darwin':
 
 config.substitutions.append( ('%lto_flags', lto_flags) )
 config.substitutions.append( ('%use_just_built_liblto', use_just_built_liblto) )
+config.substitutions.append( ('%llvm_libs_dir', llvm_libs_dir) )
+config.substitutions.append( ('%llvm_plugin_ext', llvm_plugin_ext) )
 
 def append_to_env_path(directory):
     config.environment['PATH'] = \
diff --git a/test/lit.site.cfg.in b/test/lit.site.cfg.in
index 618c83579e28c..4471ca0901149 100644
--- a/test/lit.site.cfg.in
+++ b/test/lit.site.cfg.in
@@ -19,6 +19,7 @@ config.llvm_src_root = "@LLVM_MAIN_SRC_DIR@"
 config.llvm_obj_root = "@LLVM_BINARY_DIR@"
 config.llvm_tools_dir = "@LLVM_TOOLS_DIR@"
 config.llvm_libs_dir = "@LLVM_LIBS_DIR@"
+config.llvm_plugin_ext = "@LLVM_PLUGIN_EXT@"
 config.llvm_code_generators = "@LLVM_TARGETS_TO_BUILD@".split(";")
 config.lit_tools_dir = "@LLVM_LIT_TOOLS_DIR@"
 config.swift_src_root = lit_config.params.get("swift_src_root", "@SWIFT_SOURCE_DIR@")