[Caching] Mark -typecheck action as caching supported

This is a regression causing lots of cached diagnostics tests not
functioning since the cached diagnostics processors are not initialized
for those tests which are supposed to test diagnostics caching.

The regression is caused by the fix that the typecheck module interface
job need to run a typecheck job in the sub-invocation. Now the typecheck
module interface job is correctly setup to avoid diagnostics about
unsupported file system error.

Author: cachemeifyoucan

include/swift/Basic/CASOptions.h

@@ -49,6 +49,9 @@ class CASOptions final {
   /// Cache key for imported bridging header.
   std::string BridgingHeaderPCHCacheKey;
 
+  /// Has immutable file system input.
+  bool HasImmutableFileSystem = false;
+
   /// Get the CAS configuration flags.
   void enumerateCASConfigurationFlags(
       llvm::function_ref<void(llvm::StringRef)> Callback) const;

lib/Frontend/CASOutputBackends.cpp

@@ -149,7 +149,10 @@ void SwiftCASOutputBackend::Implementation::initBackend(
   // any commands write output to `-`.
   file_types::ID mainOutputType = InputsAndOutputs.getPrincipalOutputType();
   auto addInput = [&](const InputFile &Input, unsigned Index) {
-    if (!Input.outputFilename().empty())
+    // Ignore the outputFilename for typecheck action since it is not producing
+    // an output file for that.
+    if (!Input.outputFilename().empty() &&
+        Action != FrontendOptions::ActionType::Typecheck)
       OutputToInputMap.insert(
           {Input.outputFilename(), {Index, mainOutputType}});
     Input.getPrimarySpecificPaths()

lib/Frontend/CompilerInvocation.cpp

@@ -571,13 +571,8 @@ static bool ParseCASArgs(CASOptions &Opts, ArgList &Args,
   if (const Arg*A = Args.getLastArg(OPT_bridging_header_pch_key))
     Opts.BridgingHeaderPCHCacheKey = A->getValue();
 
-  if (Opts.EnableCaching && Opts.CASFSRootIDs.empty() &&
-      Opts.ClangIncludeTrees.empty() &&
-      FrontendOptions::supportCompilationCaching(
-          FrontendOpts.RequestedAction)) {
-    Diags.diagnose(SourceLoc(), diag::error_caching_no_cas_fs);
-    return true;
-  }
+  if (!Opts.CASFSRootIDs.empty() || !Opts.ClangIncludeTrees.empty())
+    Opts.HasImmutableFileSystem = true;
 
   return false;
 }

lib/Frontend/Frontend.cpp

@@ -580,12 +580,19 @@ bool CompilerInstance::setupForReplay(const CompilerInvocation &Invoke,
 }
 
 bool CompilerInstance::setUpVirtualFileSystemOverlays() {
+  const auto &CASOpts = getInvocation().getCASOptions();
+  if (CASOpts.EnableCaching && !CASOpts.HasImmutableFileSystem &&
+      FrontendOptions::supportCompilationCaching(
+          Invocation.getFrontendOptions().RequestedAction)) {
+    Diagnostics.diagnose(SourceLoc(), diag::error_caching_no_cas_fs);
+    return true;
+  }
+
   if (Invocation.getCASOptions().requireCASFS()) {
-    const auto &Opts = getInvocation().getCASOptions();
-    if (!Opts.CASFSRootIDs.empty() || !Opts.ClangIncludeTrees.empty()) {
+    if (!CASOpts.CASFSRootIDs.empty() || !CASOpts.ClangIncludeTrees.empty()) {
       // Set up CASFS as BaseFS.
-      auto FS =
-          createCASFileSystem(*CAS, Opts.CASFSRootIDs, Opts.ClangIncludeTrees);
+      auto FS = createCASFileSystem(*CAS, CASOpts.CASFSRootIDs,
+                                    CASOpts.ClangIncludeTrees);
       if (!FS) {
         Diagnostics.diagnose(SourceLoc(), diag::error_cas,
                              toString(FS.takeError()));
@@ -599,10 +606,10 @@ bool CompilerInstance::setUpVirtualFileSystemOverlays() {
         new llvm::vfs::InMemoryFileSystem();
     const auto &ClangOpts = getInvocation().getClangImporterOptions();
 
-    if (!Opts.BridgingHeaderPCHCacheKey.empty()) {
+    if (!CASOpts.BridgingHeaderPCHCacheKey.empty()) {
       if (auto loadedBuffer = loadCachedCompileResultFromCacheKey(
               getObjectStore(), getActionCache(), Diagnostics,
-              Opts.BridgingHeaderPCHCacheKey, file_types::ID::TY_PCH,
+              CASOpts.BridgingHeaderPCHCacheKey, file_types::ID::TY_PCH,
               ClangOpts.BridgingHeader))
         MemFS->addFile(Invocation.getClangImporterOptions().BridgingHeader, 0,
                        std::move(loadedBuffer));
@@ -611,7 +618,7 @@ bool CompilerInstance::setUpVirtualFileSystemOverlays() {
             SourceLoc(), diag::error_load_input_from_cas,
             Invocation.getClangImporterOptions().BridgingHeader);
     }
-    if (!Opts.InputFileKey.empty()) {
+    if (!CASOpts.InputFileKey.empty()) {
       if (Invocation.getFrontendOptions()
               .InputsAndOutputs.getAllInputs()
               .size() != 1)
@@ -624,7 +631,7 @@ bool CompilerInstance::setUpVirtualFileSystemOverlays() {
             llvm::sys::path::filename(InputPath));
         if (auto loadedBuffer = loadCachedCompileResultFromCacheKey(
                 getObjectStore(), getActionCache(), Diagnostics,
-                Opts.InputFileKey, Type, InputPath))
+                CASOpts.InputFileKey, Type, InputPath))
           MemFS->addFile(InputPath, 0, std::move(loadedBuffer));
         else
           Diagnostics.diagnose(SourceLoc(), diag::error_load_input_from_cas,

lib/Frontend/FrontendOptions.cpp

@@ -230,7 +230,6 @@ bool FrontendOptions::supportCompilationCaching(ActionType action) {
   case ActionType::EmitImportedModules:
   case ActionType::ScanDependencies:
   case ActionType::ResolveImports:
-  case ActionType::Typecheck:
   case ActionType::DumpAST:
   case ActionType::PrintAST:
   case ActionType::PrintASTDecl:
@@ -240,6 +239,7 @@ bool FrontendOptions::supportCompilationCaching(ActionType action) {
   case ActionType::Immediate:
   case ActionType::DumpTypeInfo:
     return false;
+  case ActionType::Typecheck:
   case ActionType::TypecheckModuleFromInterface:
   case ActionType::CompileModuleFromInterface:
   case ActionType::EmitPCH:

lib/Frontend/ModuleInterfaceLoader.cpp

@@ -1765,6 +1765,8 @@ void InterfaceSubContextDelegateImpl::inheritOptionsForBuildingInterface(
   if (casOpts.EnableCaching) {
     genericSubInvocation.getCASOptions().EnableCaching = casOpts.EnableCaching;
     genericSubInvocation.getCASOptions().CASOpts = casOpts.CASOpts;
+    genericSubInvocation.getCASOptions().HasImmutableFileSystem =
+        casOpts.HasImmutableFileSystem;
     casOpts.enumerateCASConfigurationFlags(
         [&](StringRef Arg) { GenericArgs.push_back(ArgSaver.save(Arg)); });
     // ClangIncludeTree is default on when caching is enabled.

test/CAS/cached_diagnostics.swift

@@ -58,3 +58,10 @@ let _ : MyEnum? = .none // expected-warning {{assuming you mean 'Optional<MyEnum
 
 /// Verify the serialized diags have the right magic at the top.
 // CHECK-SERIALIZED: DIA
+
+// RUN: %target-swift-frontend -c -cache-compile-job -module-name Test -O -cas-path %t/cas @%t/MyApp.cmd %s \
+// RUN:   -typecheck -serialize-diagnostics -serialize-diagnostics-path %t/test.diag -Rcache-compile-job 2>&1 | %FileCheck %s -check-prefix CACHE-MISS
+// RUN: %target-swift-frontend -c -cache-compile-job -module-name Test -O -cas-path %t/cas @%t/MyApp.cmd %s \
+// RUN:   -typecheck -serialize-diagnostics -serialize-diagnostics-path %t/test.diag -Rcache-compile-job 2>&1 | %FileCheck %s -check-prefix CACHE-HIT
+// CACHE-MISS: remark: cache miss
+// CACHE-HIT: remark: replay output file '<cached-diagnostics>'