AST: Use availability to control decl visibility in public swiftinterfaces

lib/AST/ASTPrinter.cpp

@@ -20,6 +20,8 @@
 #include "swift/AST/ASTMangler.h"
 #include "swift/AST/ASTVisitor.h"
 #include "swift/AST/Attr.h"
+#include "swift/AST/AvailabilityConstraint.h"
+#include "swift/AST/AvailabilityContext.h"
 #include "swift/AST/Builtins.h"
 #include "swift/AST/ClangModuleLoader.h"
 #include "swift/AST/Comment.h"
@@ -189,6 +191,38 @@ static bool shouldPrintAllSemanticDetails(const PrintOptions &options) {
   return false;
 }
 
+static bool shouldSkipDeclInPublicInterface(const Decl *D) {
+  // @_spi should be skipped in the public interface.
+  if (D->isSPI())
+    return true;
+
+  // Decls that are unavailable at runtime in an availability domain that has
+  // been @_spiOnly imported should be hidden from the public interface of
+  // a -library-level=api module.
+  auto &ctx = D->getDeclContext()->getASTContext();
+  if (ctx.LangOpts.LibraryLevel != LibraryLevel::API)
+    return false;
+
+  auto *SF = D->getDeclContext()->getParentSourceFile();
+  if (!SF)
+    return false;
+
+  auto constraints = getAvailabilityConstraintsForDecl(
+      D, AvailabilityContext::forDeploymentTarget(ctx));
+  llvm::SmallVector<AvailabilityDomain, 4> unavailableDomains;
+  getRuntimeUnavailableDomains(constraints, unavailableDomains, ctx);
+
+  for (auto domain : unavailableDomains) {
+    if (auto *domainDecl = domain.getDecl()) {
+      if (SF->getRestrictedImportKind(domainDecl->getModuleContext()) ==
+          RestrictedImportKind::SPIOnly)
+        return true;
+    }
+  }
+
+  return false;
+}
+
 /// Get the non-recursive printing options that should be applied when
 /// printing the type of a value decl.
 static NonRecursivePrintOptions getNonRecursiveOptions(const ValueDecl *D) {
@@ -293,8 +327,7 @@ PrintOptions PrintOptions::printSwiftInterfaceFile(ModuleDecl *ModuleToPrint,
       if (D->getAttrs().hasAttribute<ImplementationOnlyAttr>())
         return false;
 
-      // Skip SPI decls if `PrintSPIs`.
-      if (options.printPublicInterface() && D->isSPI())
+      if (options.printPublicInterface() && shouldSkipDeclInPublicInterface(D))
         return false;
 
       if (auto *VD = dyn_cast<ValueDecl>(D)) {
@@ -410,8 +443,6 @@ PrintOptions PrintOptions::printSwiftInterfaceFile(ModuleDecl *ModuleToPrint,
   result.CurrentPrintabilityChecker =
       std::make_shared<ShouldPrintForModuleInterface>();
 
-  // FIXME: We don't really need 'public' on everything; we could just change
-  // the default to 'public' and mark the 'internal' things.
   result.PrintAccess = true;
 
   result.ExcludeAttrList = {

lib/AST/Attr.cpp

@@ -805,6 +805,7 @@ void DeclAttributes::print(ASTPrinter &Printer, const PrintOptions &Options,
   AttributeVector modifiers;
   bool libraryLevelAPI =
       D && D->getASTContext().LangOpts.LibraryLevel == LibraryLevel::API;
+  auto *SF = D ? D->getDeclContext()->getParentSourceFile() : nullptr;
 
   for (auto DA : llvm::reverse(FlattenedAttrs)) {
     // Don't skip implicit custom attributes. Custom attributes like global
@@ -849,6 +850,16 @@ void DeclAttributes::print(ASTPrinter &Printer, const PrintOptions &Options,
       if (!semanticAttr)
         continue;
 
+      // In the public interfaces of -library-level=api modules, skip @available
+      // attributes that refer to domains imported from @_spiOnly modules.
+      if (Options.printPublicInterface() && libraryLevelAPI) {
+        if (auto *domainDecl = semanticAttr->getDomain().getDecl()) {
+          if (SF->getRestrictedImportKind(domainDecl->getModuleContext()) ==
+              RestrictedImportKind::SPIOnly)
+            continue;
+        }
+      }
+
       if (isShortAvailable(*semanticAttr)) {
         if (semanticAttr->isSwiftLanguageModeSpecific())
           swiftVersionAvailableAttribute.emplace(*semanticAttr);

lib/AST/FeatureSet.cpp

@@ -354,14 +354,7 @@ static bool usesFeatureCoroutineAccessors(Decl *decl) {
 }
 
 UNINTERESTING_FEATURE(GeneralizedIsSameMetaTypeBuiltin)
-
-static bool usesFeatureCustomAvailability(Decl *decl) {
-  for (auto attr : decl->getSemanticAvailableAttrs()) {
-    if (attr.getDomain().isCustom())
-      return true;
-  }
-  return false;
-}
+UNINTERESTING_FEATURE(CustomAvailability)
 
 static bool usesFeatureAsyncExecutionBehaviorAttributes(Decl *decl) {
   // Explicit `@concurrent` attribute on the declaration.

lib/AST/Module.cpp

@@ -2879,6 +2879,7 @@ bool SourceFile::hasTestableOrPrivateImport(
       });
 }
 
+// FIXME: This should probably be requestified.
 RestrictedImportKind SourceFile::getRestrictedImportKind(const ModuleDecl *module) const {
   auto &imports = getASTContext().getImportCache();
   RestrictedImportKind importKind = RestrictedImportKind::MissingImport;

lib/Sema/ResilienceDiagnostics.cpp

@@ -219,6 +219,42 @@ static bool diagnoseTypeAliasDeclRefExportability(SourceLoc loc,
   return true;
 }
 
+/// Returns true if access to \p D should be diagnosed during exportability
+/// checking. These diagnostics would typically be handled by the access
+/// checker, and therefore should be suppressed to avoid duplicate diagnostics.
+/// However, extensions are special because they do not have an intrinsic access
+/// level and therefore the access checker does not currently handle them.
+/// Instead, diagnostics for decls referenced in extension signatures are
+/// deferred to exportability checking. An exportable extension is effectively a
+/// public extension.
+static bool shouldDiagnoseDeclAccess(const ValueDecl *D,
+                                     const ExportContext &where) {
+  auto reason = where.getExportabilityReason();
+  auto DC = where.getDeclContext();
+  if (!reason)
+    return false;
+
+  switch (*reason) {
+  case ExportabilityReason::ExtensionWithPublicMembers:
+  case ExportabilityReason::ExtensionWithConditionalConformances:
+    return true;
+  case ExportabilityReason::Inheritance:
+    return isa<ProtocolDecl>(D);
+  case ExportabilityReason::AvailableAttribute:
+    // If the context is an extension and that extension has an explicit
+    // access level then availability domains access has already been
+    // diagnosed.
+    if (auto *ED = dyn_cast_or_null<ExtensionDecl>(DC->getAsDecl()))
+      return !ED->getAttrs().getAttribute<AccessControlAttr>();
+    return false;
+
+  case ExportabilityReason::General:
+  case ExportabilityReason::ResultBuilder:
+  case ExportabilityReason::PropertyWrapper:
+    return false;
+  }
+}
+
 static bool diagnoseValueDeclRefExportability(SourceLoc loc, const ValueDecl *D,
                                               const ExportContext &where) {
   assert(where.mustOnlyReferenceExportedDecls());
@@ -247,41 +283,44 @@ static bool diagnoseValueDeclRefExportability(SourceLoc loc, const ValueDecl *D,
         }
       });
 
-  // Access levels from imports are reported with the others access levels.
-  // Except for extensions and protocol conformances, we report them here.
-  if (originKind == DisallowedOriginKind::NonPublicImport) {
-    bool reportHere = [&] {
-      switch (*reason) {
-        case ExportabilityReason::ExtensionWithPublicMembers:
-        case ExportabilityReason::ExtensionWithConditionalConformances:
-          return true;
-        case ExportabilityReason::Inheritance:
-          return isa<ProtocolDecl>(D);
-        case ExportabilityReason::AvailableAttribute:
-          // If the context is an extension and that extension has an explicit
-          // access level, then access has already been diagnosed for the
-          // @available attribute.
-          if (auto *ED = dyn_cast_or_null<ExtensionDecl>(DC->getAsDecl()))
-            return !ED->getAttrs().getAttribute<AccessControlAttr>();
-          return false;
-        default:
-          return false;
-      }
-    }();
-    if (!reportHere)
-      return false;
-  }
-
-  if (originKind == DisallowedOriginKind::None)
+  switch (originKind) {
+  case DisallowedOriginKind::None:
+    // The decl does not come from a source that needs to be checked for
+    // exportability.
     return false;
 
-  // Some diagnostics emitted with the `MemberImportVisibility` feature enabled
-  // subsume these diagnostics.
-  if (originKind == DisallowedOriginKind::MissingImport &&
-      ctx.LangOpts.hasFeature(Feature::MemberImportVisibility,
-                              /*allowMigration=*/true) &&
-      SF)
-    return false;
+  case DisallowedOriginKind::NonPublicImport:
+    // With a few exceptions, access levels from imports are diagnosed during
+    // access checking and should be skipped here.
+    if (!shouldDiagnoseDeclAccess(D, where))
+      return false;
+    break;
+
+  case DisallowedOriginKind::MissingImport:
+    // Some diagnostics emitted with the `MemberImportVisibility` feature
+    // enabled subsume these diagnostics.
+    if (ctx.LangOpts.hasFeature(Feature::MemberImportVisibility,
+                                /*allowMigration=*/true) &&
+        SF)
+      return false;
+    break;
+
+  case DisallowedOriginKind::SPIOnly:
+    // Availability attributes referring to availability domains from modules
+    // that are imported @_spiOnly in a -library-level=api will not be printed
+    // in the public swiftinterface of the module and should therefore not be
+    // diagnosed for exportability.
+    if (reason && reason == ExportabilityReason::AvailableAttribute &&
+        ctx.LangOpts.LibraryLevel == LibraryLevel::API)
+      return false;
+    break;
+
+  case DisallowedOriginKind::ImplementationOnly:
+  case DisallowedOriginKind::SPIImported:
+  case DisallowedOriginKind::SPILocal:
+  case DisallowedOriginKind::FragileCxxAPI:
+    break;
+  }
 
   if (auto accessor = dyn_cast<AccessorDecl>(D)) {
     // Only diagnose accessors if their disallowed origin kind differs from

test/Inputs/custom-modules/availability-domains/Lakes.h

@@ -1,6 +1,10 @@
 #include <availability_domain.h>
 
+int huron_pred(void);
+
 CLANG_ENABLED_AVAILABILITY_DOMAIN(Salt);
+CLANG_DISABLED_AVAILABILITY_DOMAIN(Erie);
+CLANG_DYNAMIC_AVAILABILITY_DOMAIN(Huron, huron_pred);
 
 #define AVAIL 0
 #define UNAVAIL 1

test/Inputs/custom-modules/availability-domains/Seas.h

@@ -1,7 +1,10 @@
 #include <availability_domain.h>
 
+int aegean_pred(void);
+
 CLANG_ENABLED_AVAILABILITY_DOMAIN(Baltic);
 CLANG_DISABLED_AVAILABILITY_DOMAIN(Mediterranean);
+CLANG_DYNAMIC_AVAILABILITY_DOMAIN(Aegean, aegean_pred);
 
 #define AVAIL 0
 #define UNAVAIL 1

test/ModuleInterface/availability_custom_domains.swift

@@ -15,18 +15,16 @@
 
 import Oceans // re-exports Rivers
 
-// CHECK:      #if compiler(>=5.3) && $CustomAvailability
-// CHECK-NEXT: @available(Colorado)
+// CHECK-NOT:  $CustomAvailability
+
+// CHECK:      @available(Colorado)
 // CHECK-NEXT: public func availableInColorado()
-// CHECK-NEXT: #endif
 @available(Colorado)
 public func availableInColorado() { }
 
-// CHECK:      #if compiler(>=5.3) && $CustomAvailability
-// CHECK-NEXT: @available(Arctic, unavailable)
+// CHECK:      @available(Arctic, unavailable)
 // CHECK-NEXT: @available(Pacific)
 // CHECK-NEXT: public func unavailableInArcticButAvailableInPacific()
-// CHECK-NEXT: #endif
 @available(Arctic, unavailable)
 @available(Pacific)
 public func unavailableInArcticButAvailableInPacific() { }