Merge pull request #41692 from nkcsgexi/spi-available

Author: nkcsgexi

docs/ReferenceGuides/UnderscoredAttributes.md

@@ -830,3 +830,10 @@ the compiler.
 
 This `async` function uses the pre-SE-0338 semantics of unsafely inheriting the caller's executor.  This is an underscored feature because the right way of inheriting an executor is to pass in the required executor and switch to it.  Unfortunately, there are functions in the standard library which need to inherit their caller's executor but cannot change their ABI because they were not defined as `@_alwaysEmitIntoClient` in the initial release.
 
+## `@_spi_available(platform, version)`
+
+Like `@available`, this attribute indicates a decl is available only as an SPI.
+This implies several behavioral changes comparing to regular `@available`:
+1. Type checker diagnoses when a client accidently exposes such a symbol in library APIs.
+2. When emitting public interfaces, `@_spi_available` is printed as `@available(platform, unavailable)`.
+3. ClangImporter imports ObjC macros `SPI_AVAILABLE` and `__SPI_AVAILABLE` to this attribute.

include/swift/AST/Attr.h

@@ -632,14 +632,16 @@ class AvailableAttr : public DeclAttribute {
                    const llvm::VersionTuple &Obsoleted,
                    SourceRange ObsoletedRange,
                    PlatformAgnosticAvailabilityKind PlatformAgnostic,
-                   bool Implicit)
+                   bool Implicit,
+                   bool IsSPI)
     : DeclAttribute(DAK_Available, AtLoc, Range, Implicit),
       Message(Message), Rename(Rename), RenameDecl(RenameDecl),
       INIT_VER_TUPLE(Introduced), IntroducedRange(IntroducedRange),
       INIT_VER_TUPLE(Deprecated), DeprecatedRange(DeprecatedRange),
       INIT_VER_TUPLE(Obsoleted), ObsoletedRange(ObsoletedRange),
       PlatformAgnostic(PlatformAgnostic),
-      Platform(Platform)
+      Platform(Platform),
+      IsSPI(IsSPI)
   {}
 
 #undef INIT_VER_TUPLE
@@ -685,6 +687,9 @@ class AvailableAttr : public DeclAttribute {
   /// The platform of the availability.
   const PlatformKind Platform;
 
+  /// Whether this is available as SPI.
+  const bool IsSPI;
+
   /// Whether this is a language-version-specific entity.
   bool isLanguageVersionSpecific() const;
 

include/swift/AST/Availability.h

@@ -209,9 +209,12 @@ class UnavailabilityReason {
 /// [lattice]: http://mathworld.wolfram.com/Lattice.html
 class AvailabilityContext {
   VersionRange OSVersion;
+  llvm::Optional<bool> SPI;
 public:
   /// Creates a context that requires certain versions of the target OS.
-  explicit AvailabilityContext(VersionRange OSVersion) : OSVersion(OSVersion) {}
+  explicit AvailabilityContext(VersionRange OSVersion,
+                               llvm::Optional<bool> SPI = llvm::None)
+    : OSVersion(OSVersion), SPI(SPI) {}
 
   /// Creates a context that imposes the constraints of the ASTContext's
   /// deployment target.
@@ -291,6 +294,10 @@ class AvailabilityContext {
   void unionWith(AvailabilityContext other) {
     OSVersion.unionWith(other.getOSVersion());
   }
+
+  bool isAvailableAsSPI() const {
+    return SPI && *SPI;
+  }
 };
 
 

include/swift/AST/Decl.h

@@ -1030,6 +1030,8 @@ class alignas(1 << DeclAlignInBits) Decl : public ASTAllocated<Decl> {
   // an @_spi context.
   bool isSPI() const;
 
+  bool isAvailableAsSPI() const;
+
   // List the SPI groups declared with @_spi or inherited by this decl.
   //
   // SPI groups are inherited from the parent contexts only if the local decl

include/swift/AST/DiagnosticsSema.def

@@ -1542,6 +1542,9 @@ ERROR(optional_attribute_initializer,none,
 ERROR(unavailable_method_non_objc_protocol,none,
       "protocol members can only be marked unavailable in an @objc protocol",
       ())
+ERROR(spi_available_malformed,none,
+      "SPI available only supports introducing version on specific platform",
+      ())
 ERROR(missing_in_class_init_1,none,
       "stored property %0 requires an initial value%select{| or should be "
       "@NSManaged}1", (Identifier, bool))

include/swift/Strings.h

@@ -64,6 +64,10 @@ constexpr static const StringLiteral BUILTIN_TYPE_NAME_PREFIX = "Builtin.";
 constexpr static const StringLiteral CLANG_MODULE_DEFUALT_SPI_GROUP_NAME =
   "OBJC_DEFAULT_SPI_GROUP";
 
+/// The attribute name for @_spi_available
+constexpr static const StringLiteral SPI_AVAILABLE_ATTRNAME =
+  "_spi_available";
+
 /// A composition class containing a StringLiteral for the names of
 /// Swift builtins. The reason we use this is to ensure that we when
 /// necessary slice off the "Builtin." prefix from these names in a

lib/AST/Attr.cpp

@@ -29,6 +29,7 @@
 #include "swift/AST/Types.h"
 #include "swift/Basic/Defer.h"
 #include "swift/Basic/QuotedString.h"
+#include "swift/Strings.h"
 #include "llvm/ADT/SmallString.h"
 #include "llvm/ADT/StringSwitch.h"
 #include "llvm/Support/ErrorHandling.h"
@@ -126,6 +127,7 @@ DeclAttrKind DeclAttribute::getAttrKindFromString(StringRef Str) {
 #define DECL_ATTR(X, CLASS, ...) .Case(#X, DAK_##CLASS)
 #define DECL_ATTR_ALIAS(X, CLASS) .Case(#X, DAK_##CLASS)
 #include "swift/AST/Attr.def"
+  .Case(SPI_AVAILABLE_ATTRNAME, DAK_Available)
   .Default(DAK_Count);
 }
 
@@ -370,6 +372,9 @@ static bool isShortAvailable(const DeclAttribute *DA) {
   if (!AvailAttr)
     return false;
 
+  if (AvailAttr->IsSPI)
+    return false;
+
   if (!AvailAttr->Introduced.hasValue())
     return false;
 
@@ -968,9 +973,23 @@ bool DeclAttribute::printImpl(ASTPrinter &Printer, const PrintOptions &Options,
   }
 
   case DAK_Available: {
-    Printer.printAttrName("@available");
-    Printer << "(";
     auto Attr = cast<AvailableAttr>(this);
+    if (!Options.PrintSPIs && Attr->IsSPI) {
+      assert(Attr->hasPlatform());
+      assert(Attr->Introduced.hasValue());
+      Printer.printAttrName("@available");
+      Printer << "(";
+      Printer << Attr->platformString();
+      Printer << ", unavailable)";
+      break;
+    }
+    if (Attr->IsSPI) {
+      std::string atSPI = (llvm::Twine("@") + SPI_AVAILABLE_ATTRNAME).str();
+      Printer.printAttrName(atSPI);
+    } else {
+      Printer.printAttrName("@available");
+    }
+    Printer << "(";
     printAvailableAttr(Attr, Printer, Options);
     Printer << ")";
     break;
@@ -1599,7 +1618,7 @@ AvailableAttr::createPlatformAgnostic(ASTContext &C,
     NoVersion, SourceRange(),
     NoVersion, SourceRange(),
     Obsoleted, SourceRange(),
-    Kind, /* isImplicit */ false);
+    Kind, /* isImplicit */ false, /*SPI*/false);
 }
 
 AvailableAttr *AvailableAttr::createForAlternative(
@@ -1610,7 +1629,7 @@ AvailableAttr *AvailableAttr::createForAlternative(
     NoVersion, SourceRange(),
     NoVersion, SourceRange(),
     NoVersion, SourceRange(),
-    PlatformAgnosticAvailabilityKind::None, /*Implicit=*/true);
+    PlatformAgnosticAvailabilityKind::None, /*Implicit=*/true, /*SPI*/false);
 }
 
 bool AvailableAttr::isActivePlatform(const ASTContext &ctx) const {
@@ -1628,7 +1647,8 @@ AvailableAttr *AvailableAttr::clone(ASTContext &C, bool implicit) const {
                                Obsoleted ? *Obsoleted : llvm::VersionTuple(),
                                implicit ? SourceRange() : ObsoletedRange,
                                PlatformAgnostic,
-                               implicit);
+                               implicit,
+                               IsSPI);
 }
 
 Optional<OriginallyDefinedInAttr::ActiveVersion>

lib/AST/Availability.cpp

@@ -41,6 +41,7 @@ struct InferredAvailability {
   Optional<llvm::VersionTuple> Introduced;
   Optional<llvm::VersionTuple> Deprecated;
   Optional<llvm::VersionTuple> Obsoleted;
+  bool IsSPI = false;
 };
 
 /// The type of a function that merges two version tuples.
@@ -51,17 +52,20 @@ typedef const llvm::VersionTuple &(*MergeFunction)(
 
 /// Apply a merge function to two optional versions, returning the result
 /// in Inferred.
-static void
+static bool
 mergeIntoInferredVersion(const Optional<llvm::VersionTuple> &Version,
                          Optional<llvm::VersionTuple> &Inferred,
                          MergeFunction Merge) {
   if (Version.hasValue()) {
     if (Inferred.hasValue()) {
       Inferred = Merge(Inferred.getValue(), Version.getValue());
+      return *Inferred == *Version;
     } else {
       Inferred = Version;
+      return true;
     }
   }
+  return false;
 }
 
 /// Merge an attribute's availability with an existing inferred availability
@@ -75,7 +79,9 @@ static void mergeWithInferredAvailability(const AvailableAttr *Attr,
                static_cast<unsigned>(Attr->getPlatformAgnosticAvailability())));
 
   // The merge of two introduction versions is the maximum of the two versions.
-  mergeIntoInferredVersion(Attr->Introduced, Inferred.Introduced, std::max);
+  if (mergeIntoInferredVersion(Attr->Introduced, Inferred.Introduced, std::max)) {
+    Inferred.IsSPI = Attr->IsSPI;
+  }
 
   // The merge of deprecated and obsoleted versions takes the minimum.
   mergeIntoInferredVersion(Attr->Deprecated, Inferred.Deprecated, std::min);
@@ -103,7 +109,8 @@ createAvailableAttr(PlatformKind Platform,
         Introduced, /*IntroducedRange=*/SourceRange(),
         Deprecated, /*DeprecatedRange=*/SourceRange(),
         Obsoleted, /*ObsoletedRange=*/SourceRange(),
-      Inferred.PlatformAgnostic, /*Implicit=*/true);
+      Inferred.PlatformAgnostic, /*Implicit=*/true,
+      Inferred.IsSPI);
 }
 
 void AvailabilityInference::applyInferredAvailableAttrs(
@@ -173,7 +180,13 @@ AvailabilityInference::annotatedAvailableRange(const Decl *D, ASTContext &Ctx) {
     return None;
 
   return AvailabilityContext{
-    VersionRange::allGTE(bestAvailAttr->Introduced.getValue())};
+    VersionRange::allGTE(bestAvailAttr->Introduced.getValue()),
+    bestAvailAttr->IsSPI};
+}
+
+bool Decl::isAvailableAsSPI() const {
+  return AvailabilityInference::availableRange(this, getASTContext())
+    .isAvailableAsSPI();
 }
 
 AvailabilityContext

lib/ClangImporter/ImportDecl.cpp

@@ -1936,7 +1936,8 @@ static void applyAvailableAttribute(Decl *decl, AvailabilityContext &info,
                                       /*Obsoleted=*/noVersion,
                                       /*ObsoletedRange*/SourceRange(),
                                       PlatformAgnosticAvailabilityKind::None,
-                                      /*Implicit=*/false);
+                                      /*Implicit=*/false,
+                                      /*SPI*/false);
 
   decl->getAttrs().add(AvAttr);
 }
@@ -2681,7 +2682,8 @@ namespace {
               /*Deprecated*/llvm::VersionTuple(), SourceRange(),
               /*Obsoleted*/llvm::VersionTuple(), SourceRange(),
               PlatformAgnosticAvailabilityKind::SwiftVersionSpecific,
-              /*Implicit*/false);
+              /*Implicit*/false,
+              /*SPI*/false);
         }
       }
 
@@ -9013,18 +9015,10 @@ void ClangImporter::Implementation::importAttributes(
         AnyUnavailable = true;
       }
 
-      if (EnableClangSPI) {
-        if (isUsingMacroName(getClangASTContext().getSourceManager(),
+      auto IsSPI = isUsingMacroName(getClangASTContext().getSourceManager(),
                               avail->getLoc(), "SPI_AVAILABLE") ||
-             isUsingMacroName(getClangASTContext().getSourceManager(),
-                              avail->getLoc(), "__SPI_AVAILABLE")) {
-          // The decl has been marked as SPI in the header by using the SPI macro,
-          // thus we add the SPI attribute to it with a default group name.
-          MappedDecl->getAttrs().add(SPIAccessControlAttr::create(SwiftContext,
-            SourceLoc(), SourceRange(),
-            SwiftContext.getIdentifier(CLANG_MODULE_DEFUALT_SPI_GROUP_NAME)));
-        }
-      }
+                   isUsingMacroName(getClangASTContext().getSourceManager(),
+                              avail->getLoc(), "__SPI_AVAILABLE");
 
       StringRef message = avail->getMessage();
 
@@ -9065,7 +9059,8 @@ void ClangImporter::Implementation::importAttributes(
                                           /*DeprecatedRange=*/SourceRange(),
                                           obsoleted,
                                           /*ObsoletedRange=*/SourceRange(),
-                                          PlatformAgnostic, /*Implicit=*/false);
+                                          PlatformAgnostic, /*Implicit=*/false,
+                                          IsSPI);
 
       MappedDecl->getAttrs().add(AvAttr);
     }

lib/Parse/ParseDecl.cpp

@@ -21,6 +21,7 @@
 #include "swift/Parse/SyntaxParsingContext.h"
 #include "swift/Syntax/SyntaxKind.h"
 #include "swift/Subsystems.h"
+#include "swift/Strings.h"
 #include "swift/AST/ASTWalker.h"
 #include "swift/AST/Attr.h"
 #include "swift/AST/GenericParamList.h"
@@ -573,7 +574,8 @@ ParserResult<AvailableAttr> Parser::parseExtendedAvailabilitySpecList(
                 Deprecated.Version, Deprecated.Range,
                 Obsoleted.Version, Obsoleted.Range,
                 PlatformAgnostic,
-                /*Implicit=*/false);
+                /*Implicit=*/false,
+                AttrName == SPI_AVAILABLE_ATTRNAME);
   return makeParserResult(Attr);
 
 }
@@ -858,7 +860,8 @@ bool Parser::parseAvailability(
           /*DeprecatedRange=*/SourceRange(),
           /*Obsoleted=*/llvm::VersionTuple(),
           /*ObsoletedRange=*/SourceRange(), PlatformAgnostic,
-          /*Implicit=*/false));
+          /*Implicit=*/false,
+          AttrName == SPI_AVAILABLE_ATTRNAME));
     }
 
     return true;