Convert ExpandMemberAttributeMacros to use split caching

Author: slavapestov

include/swift/AST/Decl.h

@@ -357,7 +357,7 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
   // for the inline bitfields.
   union { uint64_t OpaqueBits;
 
-  SWIFT_INLINE_BITFIELD_BASE(Decl, bitmax(NumDeclKindBits,8)+1+1+1+1+1+1+1,
+  SWIFT_INLINE_BITFIELD_BASE(Decl, bitmax(NumDeclKindBits,8)+1+1+1+1+1+1+1+1,
     Kind : bitmax(NumDeclKindBits,8),
 
     /// Whether this declaration is invalid.
@@ -388,7 +388,11 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
     /// True if \c ObjCInterfaceAndImplementationRequest has been computed
     /// and did \em not find anything. This is the fast path where we can bail
     /// out without checking other caches or computing anything.
-    LacksObjCInterfaceOrImplementation : 1
+    LacksObjCInterfaceOrImplementation : 1,
+
+    /// True if we're in the common case where the ExpandMemberAttributeMacros
+    /// request returned an empty array.
+    NoMemberAttributeMacros : 1
   );
 
   SWIFT_INLINE_BITFIELD_FULL(PatternBindingDecl, Decl, 1+1+2+16,
@@ -827,6 +831,7 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
   friend class MemberLookupTable;
   friend class DeclDeserializer;
   friend class RawCommentRequest;
+  friend class ExpandMemberAttributeMacros;
 
 private:
   llvm::PointerUnion<DeclContext *, ASTContext *> Context;
@@ -845,6 +850,14 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
   /// Directly set the invalid bit
   void setInvalidBit();
 
+  bool hasNoMemberAttributeMacros() const {
+    return Bits.Decl.NoMemberAttributeMacros;
+  }
+
+  void setHasNoMemberAttributeMacros() {
+    Bits.Decl.NoMemberAttributeMacros = true;
+  }
+
 protected:
 
   Decl(DeclKind kind, llvm::PointerUnion<DeclContext *, ASTContext *> context)
@@ -857,6 +870,7 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
     Bits.Decl.EscapedFromIfConfig = false;
     Bits.Decl.Hoisted = false;
     Bits.Decl.LacksObjCInterfaceOrImplementation = false;
+    Bits.Decl.NoMemberAttributeMacros = false;
   }
 
   /// Get the Clang node associated with this declaration.

include/swift/AST/TypeCheckRequests.h

@@ -4503,7 +4503,8 @@ class ExpandExtensionMacros
 class ExpandMemberAttributeMacros
     : public SimpleRequest<ExpandMemberAttributeMacros,
                            ArrayRef<unsigned>(Decl *),
-                           RequestFlags::Cached> {
+                           RequestFlags::SeparatelyCached |
+                           RequestFlags::SplitCached> {
 public:
   using SimpleRequest::SimpleRequest;
 
@@ -4514,6 +4515,9 @@ class ExpandMemberAttributeMacros
 
 public:
   bool isCached() const { return true; }
+  std::optional<ArrayRef<unsigned>> getCachedResult() const;
+  void cacheResult(ArrayRef<unsigned> result) const;
+
   void diagnoseCycle(DiagnosticEngine &diags) const;
   void noteCycleStep(DiagnosticEngine &diags) const;
 };

include/swift/AST/TypeCheckerTypeIDZone.def

@@ -503,7 +503,7 @@ SWIFT_REQUEST(TypeChecker, ExpandMacroExpansionExprRequest,
               Cached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, ExpandMemberAttributeMacros,
               ArrayRef<unsigned>(Decl *),
-              Cached, NoLocationInfo)
+              SeparatelyCached | SplitCached, NoLocationInfo)
 SWIFT_REQUEST(TypeChecker, ExpandAccessorMacros,
               ArrayRef<unsigned>(AbstractStorageDecl *),
               Cached, NoLocationInfo)

lib/AST/TypeCheckRequests.cpp

@@ -2081,6 +2081,25 @@ void ExpandExtensionMacros::noteCycleStep(DiagnosticEngine &diags) const {
                  decl->getName());
 }
 
+std::optional<ArrayRef<unsigned>> ExpandMemberAttributeMacros::getCachedResult() const {
+  auto decl = std::get<0>(getStorage());
+  if (decl->hasNoMemberAttributeMacros())
+    return ArrayRef<unsigned>();
+
+  return decl->getASTContext().evaluator.getCachedNonEmptyOutput(*this);
+}
+
+void ExpandMemberAttributeMacros::cacheResult(ArrayRef<unsigned> result) const {
+  auto decl = std::get<0>(getStorage());
+
+  if (result.empty()) {
+    decl->setHasNoMemberAttributeMacros();
+    return;
+  }
+
+  decl->getASTContext().evaluator.cacheNonEmptyOutput(*this, std::move(result));
+}
+
 void ExpandMemberAttributeMacros::diagnoseCycle(DiagnosticEngine &diags) const {
   auto decl = std::get<0>(getStorage());
   if (auto value = dyn_cast<ValueDecl>(decl)) {