[SIL] Add a new attribute [serialized_for_package] to support

package-wide resilience domain if Package CMO is enabled.

The purpose of the attribute includes:
- Indicates that certain types such as loadable types are
allowed in serialized functions in resiliently built module
if the optimization is enabled, which are otherwise disallowed.
- Used during SIL deserialization to determine whether such
functions are allowed.
- Used to determine if a callee can be inlined into a caller
that's serialized without package-cmo, e.g. with an explicit
annotation like @inlinable, where the callee was serialized
due to package-cmo.

Resolves rdar://127870822

Author: elsh

include/swift/SIL/SILFunction.h

@@ -363,6 +363,10 @@ class SILFunction
   /// The function's serialized attribute.
   bool Serialized : 1;
 
+  /// [serialized_for_package] attribute if package serialization
+  /// is enabled.
+  bool SerializedForPackage : 1;
+
   /// Specifies if this function is a thunk or a reabstraction thunk.
   ///
   /// The inliner uses this information to avoid inlining (non-trivial)
@@ -1138,6 +1142,22 @@ class SILFunction
            "too few bits for Serialized storage");
   }
 
+  /// A [serialized_for_package] attribute is used to indicate that a function
+  /// is [serialized] because of package-cmo optimization.
+  /// Package-cmo allows serializing a function containing a loadable type in
+  /// a resiliently built module, which is normally illegal. During SIL deserialization,
+  /// this attribute can be used to check whether a loaded function that was serialized
+  /// can be allowed to have loadable types. This attribute is also used to determine
+  /// if a callee can be inlined into a caller that's serialized without package-cmo, for
+  /// example, by explicitly annotating the caller decl with `@inlinable`.
+  IsSerializedForPackage_t isSerializedForPackage() const {
+    return IsSerializedForPackage_t(SerializedForPackage);
+  }
+  void
+  setSerializedForPackage(IsSerializedForPackage_t isSerializedForPackage) {
+    SerializedForPackage = isSerializedForPackage;
+  }
+
   /// Get this function's thunk attribute.
   IsThunk_t isThunk() const { return IsThunk_t(Thunk); }
   void setThunk(IsThunk_t isThunk) {

include/swift/SIL/SILLinkage.h

@@ -162,6 +162,11 @@ enum IsSerialized_t : unsigned char {
   IsSerialized
 };
 
+enum IsSerializedForPackage_t : unsigned char {
+  IsNotSerializedForPackage,
+  IsSerializedForPackage
+};
+
 /// The scope in which a subclassable class can be subclassed.
 enum class SubclassScope : uint8_t {
   /// This class can be subclassed in other modules.

lib/SIL/IR/SILFunction.cpp

@@ -523,12 +523,22 @@ ResilienceExpansion SILFunction::getResilienceExpansion() const {
   // source and is never used outside of its package;
   // Even if the module is built resiliently, return
   // maximal expansion here so aggregate types can be
-  // loadable in the same resilient domain (from a client
-  // module in the same package.
+  // treated as loadable in the same resilient domain
+  // (across modules in the same package).
   if (getModule().getSwiftModule()->serializePackageEnabled() &&
       getModule().getSwiftModule()->isResilient())
     return ResilienceExpansion::Maximal;
 
+  // If a function definition is in another module, and
+  // it was serialized due to package serialization opt,
+  // a new attribute [serialized_for_package] is added
+  // to the definition site. During deserialization, this
+  // attribute is preserved if the current module is in
+  // the same package, thus should be in the same resilience
+  // domain.
+  if (isSerializedForPackage() == IsSerializedForPackage)
+    return ResilienceExpansion::Maximal;
+
   return (isSerialized()
           ? ResilienceExpansion::Minimal
           : ResilienceExpansion::Maximal);

lib/SIL/IR/SILPrinter.cpp

@@ -3341,6 +3341,14 @@ void SILFunction::print(SILPrintContext &PrintCtx) const {
   case IsSerialized: OS << "[serialized] "; break;
   }
 
+  switch (isSerializedForPackage()) {
+  case IsNotSerializedForPackage:
+    break;
+  case IsSerializedForPackage:
+    OS << "[serialized_for_package] ";
+    break;
+  }
+
   switch (isThunk()) {
   case IsNotThunk: break;
   case IsThunk: OS << "[thunk] "; break;
@@ -3528,7 +3536,7 @@ void SILGlobalVariable::print(llvm::raw_ostream &OS, bool Verbose) const {
 
   if (isSerialized())
     OS << "[serialized] ";
-  
+
   if (isLet())
     OS << "[let] ";
 
@@ -3840,7 +3848,7 @@ void SILProperty::print(SILPrintContext &Ctx) const {
   OS << "sil_property ";
   if (isSerialized())
     OS << "[serialized] ";
-  
+
   OS << '#';
   printValueDecl(getDecl(), OS);
   if (auto sig = getDecl()->getInnermostDeclContext()
@@ -4019,6 +4027,7 @@ void SILVTable::print(llvm::raw_ostream &OS, bool Verbose) const {
   OS << "sil_vtable ";
   if (isSerialized())
     OS << "[serialized] ";
+
   if (SILType classTy = getClassType()) {
     OS << classTy;
   } else {

lib/SIL/IR/TypeLowering.cpp

@@ -2324,31 +2324,34 @@ namespace {
       if (D->isResilient()) {
         // If the type is resilient and defined in our module, make a note of
         // that, since our lowering now depends on the resilience expansion.
+        // The same should happen if the type was resilient and serialized in
+        // another module in the same package with package-cmo enabled, which
+        // treats those modules to be in the same resilience domain.
         auto declModule = D->getModuleContext();
         bool sameModule = (declModule == &TC.M);
-        if (sameModule)
+        bool serializedPackage = declModule != &TC.M &&
+                                 declModule->inSamePackage(&TC.M) &&
+                                 declModule->isResilient() &&
+                                 declModule->serializePackageEnabled();
+        auto inSameResilienceDomain = sameModule || serializedPackage;
+        if (inSameResilienceDomain)
           properties.addSubobject(RecursiveProperties::forResilient());
 
-        // If the type is in a different module, or if we're using a minimal
+        // If the type is in a different module and not in the same package
+        // resilience domain (with package-cmo), or if we're using a minimal
         // expansion, the type is address only and completely opaque to us.
-        // However, this is not true if the different module is in the same
-        // package and package serialization is enabled (resilience expansion
-        // is maximal), e.g. in case of package-cmo.
         //
-        // Note: if the type is in a different module, the lowering does
-        // not depend on the resilience expansion, so we do not need to set
-        // the isResilient() flag above.
-        bool serializedPackage = declModule->inSamePackage(&TC.M) &&
-                                 declModule->isResilient() &&
-                                 declModule->serializePackageEnabled();
-        if ((!sameModule && !serializedPackage) ||
+        // Note: if the type is in a different module and not in the same
+        // package resilience domain, the lowering does not depend on the
+        // resilience expansion, so we do not need to set the isResilient()
+        // flag above.
+        if (!inSameResilienceDomain ||
             Expansion.getResilienceExpansion() ==
                                ResilienceExpansion::Minimal) {
           properties.addSubobject(RecursiveProperties::forOpaque());
           return true;
         }
       }
-
       return false;
     }
 

lib/SIL/Parser/ParseSIL.cpp

@@ -665,7 +665,8 @@ void SILParser::convertRequirements(ArrayRef<RequirementRepr> From,
 }
 
 static bool parseDeclSILOptional(
-    bool *isTransparent, IsSerialized_t *isSerialized, bool *isCanonical,
+    bool *isTransparent, IsSerialized_t *isSerialized,
+    IsSerializedForPackage_t *isSerializedForPackage, bool *isCanonical,
     bool *hasOwnershipSSA, bool *hasResultDependsOnSelf, IsThunk_t *isThunk,
     IsDynamicallyReplaceable_t *isDynamic, IsDistributed_t *isDistributed,
     IsRuntimeAccessible_t *isRuntimeAccessible,
@@ -676,10 +677,9 @@ static bool parseDeclSILOptional(
     SILFunction **usedAdHocRequirementWitness, Identifier *objCReplacementFor,
     SILFunction::Purpose *specialPurpose, Inline_t *inlineStrategy,
     OptimizationMode *optimizationMode, PerformanceConstraints *perfConstraints,
-    bool *isPerformanceConstraint,
-    bool *markedAsUsed, StringRef *section, bool *isLet, bool *isWeakImported,
-    bool *needStackProtection, AvailabilityContext *availability,
-    bool *isWithoutActuallyEscapingThunk,
+    bool *isPerformanceConstraint, bool *markedAsUsed, StringRef *section,
+    bool *isLet, bool *isWeakImported, bool *needStackProtection,
+    AvailabilityContext *availability, bool *isWithoutActuallyEscapingThunk,
     SmallVectorImpl<std::string> *Semantics,
     SmallVectorImpl<ParsedSpecAttr> *SpecAttrs, ValueDecl **ClangDecl,
     EffectsKind *MRK, SILParser &SP, SILModule &M) {
@@ -697,6 +697,9 @@ static bool parseDeclSILOptional(
       *isTransparent = true;
     else if (isSerialized && SP.P.Tok.getText() == "serialized")
       *isSerialized = IsSerialized;
+    else if (isSerializedForPackage &&
+             SP.P.Tok.getText() == "serialized_for_package")
+      *isSerializedForPackage = IsSerializedForPackage;
     else if (isDynamic && SP.P.Tok.getText() == "dynamically_replacable")
       *isDynamic = IsDynamic;
     else if (isDistributed && SP.P.Tok.getText() == "distributed")
@@ -7106,6 +7109,7 @@ bool SILParserState::parseDeclSIL(Parser &P) {
 
   bool isTransparent = false;
   IsSerialized_t isSerialized = IsNotSerialized;
+  IsSerializedForPackage_t isSerializedForPackage = IsNotSerializedForPackage;
   bool isCanonical = false;
   IsDynamicallyReplaceable_t isDynamic = IsNotDynamic;
   IsDistributed_t isDistributed = IsNotDistributed;
@@ -7138,17 +7142,17 @@ bool SILParserState::parseDeclSIL(Parser &P) {
   Identifier objCReplacementFor;
   if (parseSILLinkage(FnLinkage, P) ||
       parseDeclSILOptional(
-          &isTransparent, &isSerialized, &isCanonical, &hasOwnershipSSA,
-          &hasResultDependsOnSelf, &isThunk, &isDynamic, &isDistributed,
-          &isRuntimeAccessible, &forceEnableLexicalLifetimes,
+          &isTransparent, &isSerialized, &isSerializedForPackage, &isCanonical,
+          &hasOwnershipSSA, &hasResultDependsOnSelf, &isThunk, &isDynamic,
+          &isDistributed, &isRuntimeAccessible, &forceEnableLexicalLifetimes,
           &useStackForPackMetadata, &hasUnsafeNonEscapableResult,
           &isExactSelfClass, &DynamicallyReplacedFunction,
           &AdHocWitnessFunction, &objCReplacementFor, &specialPurpose,
           &inlineStrategy, &optimizationMode, &perfConstr,
-          &isPerformanceConstraint, &markedAsUsed,
-          &section, nullptr, &isWeakImported, &needStackProtection,
-          &availability, &isWithoutActuallyEscapingThunk, &Semantics,
-          &SpecAttrs, &ClangDecl, &MRK, FunctionState, M) ||
+          &isPerformanceConstraint, &markedAsUsed, &section, nullptr,
+          &isWeakImported, &needStackProtection, &availability,
+          &isWithoutActuallyEscapingThunk, &Semantics, &SpecAttrs, &ClangDecl,
+          &MRK, FunctionState, M) ||
       P.parseToken(tok::at_sign, diag::expected_sil_function_name) ||
       P.parseIdentifier(FnName, FnNameLoc, /*diagnoseDollarPrefix=*/false,
                         diag::expected_sil_function_name) ||
@@ -7173,6 +7177,8 @@ bool SILParserState::parseDeclSIL(Parser &P) {
     FunctionState.F->setBare(IsBare);
     FunctionState.F->setTransparent(IsTransparent_t(isTransparent));
     FunctionState.F->setSerialized(IsSerialized_t(isSerialized));
+    FunctionState.F->setSerializedForPackage(
+        IsSerializedForPackage_t(isSerializedForPackage));
     FunctionState.F->setWasDeserializedCanonical(isCanonical);
     if (!hasOwnershipSSA)
       FunctionState.F->setOwnershipEliminated();
@@ -7399,10 +7405,9 @@ bool SILParserState::parseSILGlobal(Parser &P) {
       parseDeclSILOptional(nullptr, &isSerialized, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
-                           nullptr,
-                           nullptr, nullptr, nullptr, nullptr, nullptr, &isLet,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
-                           nullptr, nullptr, State, M) ||
+                           nullptr, &isLet, nullptr, nullptr, nullptr, nullptr,
+                           nullptr, nullptr, nullptr, nullptr, State, M) ||
       P.parseToken(tok::at_sign, diag::expected_sil_value_name) ||
       P.parseIdentifier(GlobalName, NameLoc, /*diagnoseDollarPrefix=*/false,
                         diag::expected_sil_value_name) ||
@@ -7454,7 +7459,7 @@ bool SILParserState::parseSILProperty(Parser &P) {
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
-                           nullptr, nullptr, nullptr, SP, M))
+                           nullptr, nullptr, nullptr, nullptr, SP, M))
     return true;
 
   ValueDecl *VD;
@@ -7524,7 +7529,7 @@ bool SILParserState::parseSILVTable(Parser &P) {
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
-                           nullptr, nullptr, nullptr, VTableState, M))
+                           nullptr, nullptr, nullptr, nullptr, VTableState, M))
     return true;
 
 
@@ -7647,7 +7652,8 @@ bool SILParserState::parseSILMoveOnlyDeinit(Parser &parser) {
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
-                           nullptr, nullptr, nullptr, moveOnlyDeinitTableState, M))
+                           nullptr, nullptr, nullptr, nullptr,
+                           moveOnlyDeinitTableState, M))
     return true;
 
   // Parse the class name.
@@ -8134,7 +8140,7 @@ bool SILParserState::parseSILWitnessTable(Parser &P) {
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
                            nullptr, nullptr, nullptr, nullptr, nullptr, nullptr,
-                           nullptr, nullptr, nullptr, WitnessState, M))
+                           nullptr, nullptr, nullptr, nullptr, WitnessState, M))
     return true;
 
   // Parse the protocol conformance.