Support bypassing resilience checks for package decls at use site in a package.

By default package decls are treated as resilient, similar to public (non-frozen).
This PR adds support to allow direct access to package decls at use site if opted-in.
Requires the loaded module to be a binary module in the same package.

Resolves rdar://121626315

Author: elsh

include/swift/AST/Decl.h

@@ -4097,6 +4097,8 @@ class NominalTypeDecl : public GenericTypeDecl, public IterableDeclContext {
   /// type from the given module?
   bool isResilient(ModuleDecl *M, ResilienceExpansion expansion) const;
 
+  bool allowBypassResilienceInPackage() const;
+
   /// Determine whether we have already attempted to add any
   /// implicitly-defined initializers to this declaration.
   bool addedImplicitInitializers() const {
@@ -5852,6 +5854,8 @@ class AbstractStorageDecl : public ValueDecl {
   /// property from the given module?
   bool isResilient(ModuleDecl *M, ResilienceExpansion expansion) const;
 
+  bool allowBypassResilienceInPackage() const;
+
   /// True if the storage can be referenced by a keypath directly.
   /// Otherwise, its override must be referenced.
   bool isValidKeyPathComponent() const;

include/swift/AST/DeclContext.h

@@ -530,6 +530,9 @@ class alignas(1 << DeclContextAlignInBits) DeclContext
   LLVM_READONLY
   PackageUnit *getPackageContext(bool lookupIfNotCurrent = false) const;
 
+  LLVM_READONLY
+  bool allowBypassResilienceInPackage() const;
+
   /// Returns the module context that contains this context.
   LLVM_READONLY
   ModuleDecl *getParentModule() const;

include/swift/AST/Module.h

@@ -480,6 +480,10 @@ class ModuleDecl
     return Identifier();
   }
 
+  bool inPackage(std::string packageName) {
+    return !getPackageName().empty() && getPackageName().str() == packageName;
+  }
+
   /// Get the package associated with this module
   PackageUnit *getPackage() const { return Package; }
 

include/swift/Basic/LangOptions.h

@@ -186,6 +186,9 @@ namespace swift {
     /// Disable API availability checking.
     bool DisableAvailabilityChecking = false;
 
+    /// Enable optimization to bypass resilience checks in a package
+    bool EnableBypassResilienceInPackage = false;
+
     /// Optimization mode for unavailable declarations.
     llvm::Optional<UnavailableDeclOptimization> UnavailableDeclOptimizationMode;
 

include/swift/Option/Options.td

@@ -516,6 +516,10 @@ def unavailable_decl_optimization_EQ : Joined<["-"], "unavailable-decl-optimizat
            "value may be 'none' (no optimization) or 'complete' (code is not "
            "generated at all unavailable declarations)">;
 
+def package_bypass_resilience_optimization : Flag<["-"], "package-bypass-resilience-optimization">,
+  Flags<[FrontendOption]>,
+  HelpText<"Enable optimization to bypass resilience within a package">;
+
 def library_level : Separate<["-"], "library-level">,
   MetaVarName<"<level>">,
   Flags<[HelpHidden, FrontendOption, ModuleInterfaceOption]>,

lib/AST/Decl.cpp

@@ -2980,11 +2980,32 @@ bool AbstractStorageDecl::isFormallyResilient() const {
   return true;
 }
 
+bool AbstractStorageDecl::allowBypassResilienceInPackage() const {
+  auto shouldAllow = true;
+  // Only allow bypassing resilience checks for package decls
+  // if the enclosing decl's non-resilient
+  if (auto enclosingNominal = dyn_cast<NominalTypeDecl>(getDeclContext())) {
+    shouldAllow = !enclosingNominal->isResilient();
+  } else if (auto enclosingExt = dyn_cast<ExtensionDecl>(getDeclContext())) {
+    if (auto nominal = enclosingExt->getExtendedNominal())
+      shouldAllow = !nominal->isResilient();
+  }
+  if (shouldAllow &&
+      getFormalAccessScope(/*useDC=*/nullptr,
+                           /*treatUsableFromInlineAsPublic=*/true).isPackage())
+    return getModuleContext()->allowBypassResilienceInPackage();
+  return false;
+}
+
 bool AbstractStorageDecl::isResilient() const {
   if (!isFormallyResilient())
     return false;
-
-  return getModuleContext()->isResilient();
+  if (!getModuleContext()->isResilient())
+    return false;
+  // Allows bypassing resilience checks for package
+  // decls within a package whether the loaded module
+  // was built resiliently or not.
+  return !allowBypassResilienceInPackage();
 }
 
 bool AbstractStorageDecl::isResilient(ModuleDecl *M,
@@ -5063,11 +5084,32 @@ bool NominalTypeDecl::isFormallyResilient() const {
   return true;
 }
 
+bool NominalTypeDecl::allowBypassResilienceInPackage() const {
+  auto shouldAllow = true;
+  // Only allow bypassing resilience checks for package decls
+  // if the enclosing decl's non-resilient
+  if (auto enclosingNominal = dyn_cast<NominalTypeDecl>(getDeclContext())) {
+    shouldAllow = !enclosingNominal->isResilient();
+  } else if (auto enclosingExt = dyn_cast<ExtensionDecl>(getDeclContext())) {
+    if (auto nominal = enclosingExt->getExtendedNominal())
+      shouldAllow = !nominal->isResilient();
+  }
+  if (shouldAllow &&
+      getFormalAccessScope(/*useDC=*/nullptr,
+                           /*treatUsableFromInlineAsPublic=*/true).isPackage())
+    return getModuleContext()->allowBypassResilienceInPackage();
+  return false;
+}
+
 bool NominalTypeDecl::isResilient() const {
   if (!isFormallyResilient())
     return false;
-
-  return getModuleContext()->isResilient();
+  if (!getModuleContext()->isResilient())
+    return false;
+  // Allows bypassing resilience checks for package
+  // decls within a package whether the loaded module
+  // was built resiliently or not.
+  return !allowBypassResilienceInPackage();
 }
 
 DestructorDecl *NominalTypeDecl::getValueTypeDestructor() {

lib/AST/DeclContext.cpp

@@ -300,6 +300,12 @@ PackageUnit *DeclContext::getPackageContext(bool lookupIfNotCurrent) const {
   return nullptr;
 }
 
+bool DeclContext::allowBypassResilienceInPackage() const {
+  return getASTContext().LangOpts.EnableBypassResilienceInPackage &&
+  getParentModule()->inPackage(getASTContext().LangOpts.PackageName) &&
+  !getParentModule()->isBuiltFromInterface();
+}
+
 ModuleDecl *DeclContext::getParentModule() const {
   // If the current context is PackageUnit, return the module
   // decl context pointing to the current context. This check

lib/AST/ProtocolConformance.cpp

@@ -348,8 +348,12 @@ bool NormalProtocolConformance::isResilient() const {
   // individual witnesses.
   if (!getDeclContext()->getSelfNominalTypeDecl()->isResilient())
     return false;
-
-  return getDeclContext()->getParentModule()->isResilient();
+  if (!getDeclContext()->getParentModule()->isResilient())
+    return false;
+  // Allows bypassing resilience checks for package
+  // decls within a package whether the loaded module
+  // was built resiliently or not.
+  return !getDeclContext()->getSelfNominalTypeDecl()->allowBypassResilienceInPackage();
 }
 
 llvm::Optional<ArrayRef<Requirement>>

lib/Driver/ToolChains.cpp

@@ -299,6 +299,7 @@ void ToolChain::addCommonFrontendArgs(const OutputInfo &OI,
   inputArgs.AddLastArg(arguments, options::OPT_Rpass_missed_EQ);
   inputArgs.AddLastArg(arguments, options::OPT_suppress_warnings);
   inputArgs.AddLastArg(arguments, options::OPT_suppress_remarks);
+  inputArgs.AddLastArg(arguments, options::OPT_package_bypass_resilience_optimization);
   inputArgs.AddLastArg(arguments, options::OPT_profile_generate);
   inputArgs.AddLastArg(arguments, options::OPT_profile_use);
   inputArgs.AddLastArg(arguments, options::OPT_profile_coverage_mapping);
@@ -551,7 +552,7 @@ ToolChain::constructInvocation(const CompileJobAction &job,
   if (context.Args.hasArg(options::OPT_CrossModuleOptimization)) {
     Arguments.push_back("-cross-module-optimization");
   }
-                                 
+
   if (context.Args.hasArg(options::OPT_ExperimentalPerformanceAnnotations)) {
     Arguments.push_back("-experimental-performance-annotations");
   }

lib/Frontend/CompilerInvocation.cpp

@@ -631,6 +631,9 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
   Opts.EnablePackageInterfaceLoad = Args.hasArg(OPT_experimental_package_interface_load) ||
                                     ::getenv("SWIFT_ENABLE_PACKAGE_INTERFACE_LOAD");
 
+  Opts.EnableBypassResilienceInPackage =
+  Args.hasArg(OPT_package_bypass_resilience_optimization);
+
   Opts.DisableAvailabilityChecking |=
       Args.hasArg(OPT_disable_availability_checking);
   if (Args.hasArg(OPT_check_api_availability_only))

lib/Sema/ImportResolution.cpp

@@ -762,8 +762,7 @@ void UnboundImport::validateInterfaceWithPackageName(ModuleDecl *topLevelModule,
 
   // If source file is .swift or non-interface, show diags when importing an interface file
   ASTContext &ctx = topLevelModule->getASTContext();
-  if (!topLevelModule->getPackageName().empty() &&
-      topLevelModule->getPackageName().str() == ctx.LangOpts.PackageName &&
+  if (topLevelModule->inPackage(ctx.LangOpts.PackageName) &&
       topLevelModule->isBuiltFromInterface() &&
       !topLevelModule->getModuleSourceFilename().endswith(".package.swiftinterface")) {
       ctx.Diags.diagnose(import.module.getModulePath().front().Loc,

test/IRGen/package_resilience.swift

@@ -1,20 +1,18 @@
 //
 // Unlike its counterparts in the other *_resilience.swift files, the goal is
 // for the package's component modules to all be considered within the same
-// resilience domain. This file ensures that we use direct access as much as
-// possible.
+// resilience domain. This file ensures that we use direct access to package
+// decls at use site as much as possible with -package-bypass-resilience-optimization.
 //
 
-// REQUIRES: rdar118947451
-
 // RUN: %empty-directory(%t)
 // RUN: %{python} %utils/chex.py < %s > %t/package_resilience.swift
 // RUN: %target-swift-frontend -package-name MyPkg -emit-module -enable-library-evolution -emit-module-path=%t/resilient_struct.swiftmodule -module-name=resilient_struct %S/Inputs/package_types/resilient_struct.swift
 // RUN: %target-swift-frontend -package-name MyPkg -emit-module -enable-library-evolution -emit-module-path=%t/resilient_enum.swiftmodule -module-name=resilient_enum -I %t %S/Inputs/package_types/resilient_enum.swift
 // RUN: %target-swift-frontend -package-name MyPkg -emit-module -enable-library-evolution -emit-module-path=%t/resilient_class.swiftmodule -module-name=resilient_class -I %t %S/Inputs/package_types/resilient_class.swift
-// RUN: %target-swift-frontend -package-name MyPkg -enable-objc-interop -I %t -emit-ir -enable-library-evolution %t/package_resilience.swift | %FileCheck %t/package_resilience.swift --check-prefixes=CHECK,CHECK-objc,CHECK-objc%target-ptrsize,CHECK-%target-ptrsize,CHECK-%target-cpu,CHECK-%target-import-type-objc-STABLE-ABI-%target-mandates-stable-abi,CHECK-%target-sdk-name -DINT=i%target-ptrsize -D#MDWORDS=7 -D#MDSIZE32=52 -D#MDSIZE64=80 -D#WORDSIZE=%target-alignment
-// RUN: %target-swift-frontend -package-name MyPkg -disable-objc-interop -I %t -emit-ir -enable-library-evolution %t/package_resilience.swift | %FileCheck %t/package_resilience.swift --check-prefixes=CHECK,CHECK-native,CHECK-native%target-ptrsize,CHECK-%target-ptrsize,CHECK-%target-cpu,CHECK-native-STABLE-ABI-%target-mandates-stable-abi,CHECK-%target-sdk-name -DINT=i%target-ptrsize -D#MDWORDS=4 -D#MDSIZE32=40 -D#MDSIZE64=56 -D#WORDSIZE=%target-alignment
-// RUN: %target-swift-frontend -package-name MyPkg -I %t -emit-ir -enable-library-evolution -O %t/package_resilience.swift -package-name MyPkg
+// RUN: %target-swift-frontend -package-name MyPkg -package-bypass-resilience-optimization -enable-objc-interop -I %t -emit-ir -enable-library-evolution %t/package_resilience.swift | %FileCheck %t/package_resilience.swift --check-prefixes=CHECK,CHECK-objc,CHECK-objc%target-ptrsize,CHECK-%target-ptrsize,CHECK-%target-cpu,CHECK-%target-import-type-objc-STABLE-ABI-%target-mandates-stable-abi,CHECK-%target-sdk-name -DINT=i%target-ptrsize -D#MDWORDS=7 -D#MDSIZE32=52 -D#MDSIZE64=80 -D#WORDSIZE=%target-alignment
+// RUN: %target-swift-frontend -package-name MyPkg -package-bypass-resilience-optimization -disable-objc-interop -I %t -emit-ir -enable-library-evolution %t/package_resilience.swift | %FileCheck %t/package_resilience.swift --check-prefixes=CHECK,CHECK-native,CHECK-native%target-ptrsize,CHECK-%target-ptrsize,CHECK-%target-cpu,CHECK-native-STABLE-ABI-%target-mandates-stable-abi,CHECK-%target-sdk-name -DINT=i%target-ptrsize -D#MDWORDS=4 -D#MDSIZE32=40 -D#MDSIZE64=56 -D#WORDSIZE=%target-alignment
+// RUN: %target-swift-frontend -package-name MyPkg -package-bypass-resilience-optimization -I %t -emit-ir -enable-library-evolution -O %t/package_resilience.swift -package-name MyPkg
 // REQUIRES: objc_codegen
 // REQUIRES: OS=macosx || OS=ios || OS=tvos || OS=watchos
 // REQUIRES: CPU=x86_64 || CPU=arm64