Convert LifetimeDependenceInfoRequest to use split caching

Author: slavapestov

include/swift/AST/Decl.h

@@ -7490,6 +7490,7 @@ class AbstractFunctionDecl : public GenericContext, public ValueDecl {
   friend class ParseAbstractFunctionBodyRequest;
   friend class TypeCheckFunctionBodyRequest;
   friend class IsFunctionBodySkippedRequest;
+  friend class LifetimeDependenceInfoRequest;
 
   CaptureInfo Captures;
 
@@ -7505,6 +7506,7 @@ class AbstractFunctionDecl : public GenericContext, public ValueDecl {
   struct {
     unsigned NeedsNewVTableEntryComputed : 1;
     unsigned NeedsNewVTableEntry : 1;
+    unsigned NoLifetimeDependenceInfo : 1;
   } LazySemanticInfo = { };
 
   AbstractFunctionDecl(DeclKind Kind, DeclContext *Parent, DeclName Name,

include/swift/AST/TypeCheckRequests.h

@@ -4995,7 +4995,8 @@ class LifetimeDependenceInfoRequest
     : public SimpleRequest<LifetimeDependenceInfoRequest,
                            std::optional<LifetimeDependenceInfo>(
                                AbstractFunctionDecl *),
-                           RequestFlags::Cached> {
+                           RequestFlags::SeparatelyCached |
+                           RequestFlags::SplitCached> {
 public:
   using SimpleRequest::SimpleRequest;
 
@@ -5006,9 +5007,10 @@ class LifetimeDependenceInfoRequest
   evaluate(Evaluator &evaluator, AbstractFunctionDecl *AFD) const;
 
 public:
-  // Caching.
+  // Separate caching.
   bool isCached() const { return true; }
-
+  std::optional<std::optional<LifetimeDependenceInfo>> getCachedResult() const;
+  void cacheResult(std::optional<LifetimeDependenceInfo> value) const;
 };
 
 class CaptureInfoRequest :

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -574,7 +574,8 @@ SWIFT_REQUEST(TypeChecker, ImportDeclRequest,
                   const SourceFile *sf, const ModuleDecl *mod),
               Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, LifetimeDependenceInfoRequest,
-              LifetimeDependenceInfo(AbstractFunctionDecl *), Cached, NoLocationInfo)
+              LifetimeDependenceInfo(AbstractFunctionDecl *),
+              SeparatelyCached | SplitCached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, SuppressesConformanceRequest,
               bool(NominalTypeDecl *decl, KnownProtocolKind kp),
               SeparatelyCached, NoLocationInfo)

lib/AST/TypeCheckRequests.cpp

@@ -2466,6 +2466,36 @@ void ExpandBodyMacroRequest::noteCycleStep(DiagnosticEngine &diags) const {
                  decl->getName());
 }
 
+//----------------------------------------------------------------------------//
+// LifetimeDependenceInfoRequest computation.
+//----------------------------------------------------------------------------//
+
+std::optional<std::optional<LifetimeDependenceInfo>>
+LifetimeDependenceInfoRequest::getCachedResult() const {
+  auto *func = std::get<0>(getStorage());
+
+  if (func->LazySemanticInfo.NoLifetimeDependenceInfo)
+    return std::optional(std::optional<LifetimeDependenceInfo>());
+
+  return func->getASTContext().evaluator.getCachedNonEmptyOutput(*this);
+}
+
+void LifetimeDependenceInfoRequest::cacheResult(
+    std::optional<LifetimeDependenceInfo> result) const {
+  auto *func = std::get<0>(getStorage());
+  
+  if (!result) {
+    func->LazySemanticInfo.NoLifetimeDependenceInfo = 1;
+    return;
+  }
+
+  func->getASTContext().evaluator.cacheNonEmptyOutput(*this, std::move(result));
+}
+
+//----------------------------------------------------------------------------//
+// CaptureInfoRequest computation.
+//----------------------------------------------------------------------------//
+
 std::optional<CaptureInfo>
 CaptureInfoRequest::getCachedResult() const {
   auto *func = std::get<0>(getStorage());
@@ -2477,6 +2507,10 @@ void CaptureInfoRequest::cacheResult(CaptureInfo info) const {
   return func->setCaptureInfo(info);
 }
 
+//----------------------------------------------------------------------------//
+// ParamCaptureInfoRequest computation.
+//----------------------------------------------------------------------------//
+
 std::optional<CaptureInfo>
 ParamCaptureInfoRequest::getCachedResult() const {
   auto *param = std::get<0>(getStorage());