[Frontend][AST][IRGen] Improve availability support.

CMakeLists.txt

@@ -101,9 +101,11 @@ include(FetchContent)
 check_language(Swift)
 if(CMAKE_Swift_COMPILER)
   enable_language(Swift)
+  set(DEFAULT_SWIFT_MIN_RUNTIME_VERSION "${CMAKE_Swift_COMPILER_VERSION}")
 else()
   message(STATUS "WARNING! Did not find a host compiler swift?! Can not build
                   any compiler host sources written in Swift")
+  set(DEFAULT_SWIFT_MIN_RUNTIME_VERSION)
 endif()
 
 # A convenience pattern to match Darwin platforms. Example:
@@ -464,6 +466,10 @@ set(SWIFT_DARWIN_MODULE_ARCHS "" CACHE STRING
 targets on Darwin platforms. These targets are in addition to the full \
 library targets.")
 
+set(SWIFT_MIN_RUNTIME_VERSION "${DEFAULT_SWIFT_MIN_RUNTIME_VERSION}" CACHE STRING
+  "Specify the minimum version of the runtime that we target when building \
+the compiler itself. This is used on non-Darwin platforms to ensure \
+that it's possible to build the compiler using host tools.")
 
 #
 # User-configurable Android specific options.

SwiftCompilerSources/CMakeLists.txt

@@ -106,7 +106,13 @@ function(add_swift_compiler_modules_library name)
       "-Xcc" "-std=c++17"
       "-Xcc" "-DCOMPILED_WITH_SWIFT" "-Xcc" "-DSWIFT_TARGET"
       "-Xcc" "-UIBOutlet" "-Xcc" "-UIBAction" "-Xcc" "-UIBInspectable")
+
   if (NOT BOOTSTRAPPING_MODE STREQUAL "HOSTTOOLS")
+    if(SWIFT_MIN_RUNTIME_VERSION)
+      list(APPEND swift_compile_options
+        "-Xfrontend" "-min-runtime-version"
+        "-Xfrontend" "${SWIFT_MIN_RUNTIME_VERSION}")
+    endif()
     list(APPEND swift_compile_options "-Xfrontend" "-disable-implicit-string-processing-module-import")
   endif()
 

include/swift/AST/ASTContext.h

@@ -18,6 +18,7 @@
 #define SWIFT_AST_ASTCONTEXT_H
 
 #include "swift/AST/ASTAllocated.h"
+#include "swift/AST/Availability.h"
 #include "swift/AST/Evaluator.h"
 #include "swift/AST/GenericSignature.h"
 #include "swift/AST/Identifier.h"
@@ -876,159 +877,124 @@ class ASTContext final {
     addCleanup([&object]{ object.~T(); });
   }
 
-  /// Get the runtime availability of the class metadata update callback
-  /// mechanism for the target platform.
-  AvailabilityContext getObjCMetadataUpdateCallbackAvailability();
-
-  /// Get the runtime availability of the objc_getClass() hook for the target
-  /// platform.
-  AvailabilityContext getObjCGetClassHookAvailability();
-
-  /// Get the runtime availability of features introduced in the Swift 5.0
-  /// compiler for the target platform.
-  AvailabilityContext getSwift50Availability();
-
-  /// Get the runtime availability of the opaque types language feature for the
-  /// target platform.
-  AvailabilityContext getOpaqueTypeAvailability();
-
-  /// Get the runtime availability of the objc_loadClassref() entry point for
-  /// the target platform.
-  AvailabilityContext getObjCClassStubsAvailability();
-
-  /// Get the runtime availability of features introduced in the Swift 5.1
-  /// compiler for the target platform.
-  AvailabilityContext getSwift51Availability();
-
-  /// Get the runtime availability of
-  /// swift_getTypeByMangledNameInContextInMetadataState.
-  AvailabilityContext getTypesInAbstractMetadataStateAvailability();
-
-  /// Get the runtime availability of support for prespecialized generic 
-  /// metadata.
-  AvailabilityContext getPrespecializedGenericMetadataAvailability();
-
-  /// Get the runtime availability of the swift_compareTypeContextDescriptors
-  /// for the target platform.
-  AvailabilityContext getCompareTypeContextDescriptorsAvailability();
-
-  /// Get the runtime availability of the
-  /// swift_compareProtocolConformanceDescriptors entry point for the target
-  /// platform.
-  AvailabilityContext getCompareProtocolConformanceDescriptorsAvailability();
-
-  /// Get the runtime availability of support for inter-module prespecialized
-  /// generic metadata.
-  AvailabilityContext getIntermodulePrespecializedGenericMetadataAvailability();
-
-  /// Get the runtime availability of support for concurrency.
-  AvailabilityContext getConcurrencyAvailability();
-
-  /// Get the runtime availability of task executors.
-  AvailabilityContext getTaskExecutorAvailability();
-
-  /// Get the runtime availability of the `DiscardingTaskGroup`,
-  /// and supporting runtime functions function
-  AvailabilityContext getConcurrencyDiscardingTaskGroupAvailability();
-
-  /// Get the back-deployed availability for concurrency.
-  AvailabilityContext getBackDeployedConcurrencyAvailability();
-
-  /// The the availability since when distributed actors are able to have custom
-  /// executors.
-  AvailabilityContext
-  getConcurrencyDistributedActorWithCustomExecutorAvailability();
-
-  /// Get the runtime availability of support for differentiation.
-  AvailabilityContext getDifferentiationAvailability();
-
-  /// Get the runtime availability of support for typed throws.
-  AvailabilityContext getTypedThrowsAvailability();
-
-  /// Get the runtime availability of getters and setters of multi payload enum
-  /// tag single payloads.
-  AvailabilityContext getMultiPayloadEnumTagSinglePayload();
-
-  /// Get the runtime availability of the Objective-C enabled
-  /// swift_isUniquelyReferenced functions.
-  AvailabilityContext getObjCIsUniquelyReferencedAvailability();
+  /// Get the availability of features introduced in the specified version
+  /// of the Swift compiler for the target platform.
+  AvailabilityContext getSwiftAvailability(unsigned major, unsigned minor) const;
+
+  // For each feature defined in FeatureAvailability, define two functions;
+  // the latter, with the suffix RuntimeAvailabilty, is for use with
+  // AvailabilityContext::forRuntimeTarget(), and only looks at the Swift
+  // runtime version.
+#define FEATURE(N, V)                                                       \
+  inline AvailabilityContext get##N##Availability() const {                 \
+    return getSwiftAvailability V;                                          \
+  }                                                                         \
+  inline AvailabilityContext get##N##RuntimeAvailability() const {          \
+    return AvailabilityContext(VersionRange::allGTE(llvm::VersionTuple V)); \
+  }
 
-  /// Get the runtime availability of metadata manipulation runtime functions
-  /// for extended existential types.
-  AvailabilityContext getParameterizedExistentialRuntimeAvailability();
+  #include "swift/AST/FeatureAvailability.def"
 
-  /// Get the runtime availability of array buffers placed in constant data
-  /// sections.
-  AvailabilityContext getStaticReadOnlyArraysAvailability();
+  /// Get the runtime availability of features that have been introduced in the
+  /// Swift compiler for future versions of the target platform.
+  AvailabilityContext getSwiftFutureAvailability() const;
 
-  /// Get the runtime availability of runtime functions for
-  /// variadic generic types.
-  AvailabilityContext getVariadicGenericTypeAvailability();
+  /// Returns `true` if versioned availability annotations are supported for the
+  /// target triple.
+  bool supportsVersionedAvailability() const;
 
-  /// Get the runtime availability of the conformsToProtocol runtime entrypoint
-  /// that takes a signed protocol descriptor pointer.
-  AvailabilityContext getSignedConformsToProtocolAvailability();
+  //===--------------------------------------------------------------------===//
+  // Compatibility availability functions
+  //===--------------------------------------------------------------------===//
 
-  /// Get the runtime availability of runtime entrypoints that take signed type
-  /// descriptors.
-  AvailabilityContext getSignedDescriptorAvailability();
+  // Note: Don't add more of these version-specific availability functions;
+  // just use getSwiftAvailability() instead.
 
-  /// Get the runtime availability of the swift_initRawStructMetadata entrypoint
-  /// that fixes up the value witness table of @_rawLayout dependent types.
-  AvailabilityContext getInitRawStructMetadataAvailability();
+  /// Get the runtime availability of features introduced in the Swift 5.0
+  /// compiler for the target platform.
+  inline AvailabilityContext getSwift50Availability() const {
+    return getSwiftAvailability(5, 0);
+  }
 
-  /// Get the runtime availability of being able to use symbolic references to
-  /// objective c protocols.
-  AvailabilityContext getObjCSymbolicReferencesAvailability();
+  /// Get the runtime availability of features introduced in the Swift 5.1
+  /// compiler for the target platform.
+  inline AvailabilityContext getSwift51Availability() const {
+    return getSwiftAvailability(5, 1);
+  }
 
   /// Get the runtime availability of features introduced in the Swift 5.2
   /// compiler for the target platform.
-  AvailabilityContext getSwift52Availability();
+  inline AvailabilityContext getSwift52Availability() const {
+    return getSwiftAvailability(5, 2);
+  }
 
   /// Get the runtime availability of features introduced in the Swift 5.3
   /// compiler for the target platform.
-  AvailabilityContext getSwift53Availability();
+  inline AvailabilityContext getSwift53Availability() const {
+    return getSwiftAvailability(5, 3);
+  }
 
   /// Get the runtime availability of features introduced in the Swift 5.4
   /// compiler for the target platform.
-  AvailabilityContext getSwift54Availability();
+  inline AvailabilityContext getSwift54Availability() const {
+    return getSwiftAvailability(5, 4);
+  }
 
   /// Get the runtime availability of features introduced in the Swift 5.5
   /// compiler for the target platform.
-  AvailabilityContext getSwift55Availability();
+  inline AvailabilityContext getSwift55Availability() const {
+    return getSwiftAvailability(5, 5);
+  }
 
   /// Get the runtime availability of features introduced in the Swift 5.6
   /// compiler for the target platform.
-  AvailabilityContext getSwift56Availability();
+  inline AvailabilityContext getSwift56Availability() const {
+    return getSwiftAvailability(5, 6);
+  }
 
   /// Get the runtime availability of features introduced in the Swift 5.7
   /// compiler for the target platform.
-  AvailabilityContext getSwift57Availability();
+  inline AvailabilityContext getSwift57Availability() const {
+    return getSwiftAvailability(5, 7);
+  }
 
   /// Get the runtime availability of features introduced in the Swift 5.8
   /// compiler for the target platform.
-  AvailabilityContext getSwift58Availability();
+  inline AvailabilityContext getSwift58Availability() const {
+    return getSwiftAvailability(5, 8);
+  }
 
   /// Get the runtime availability of features introduced in the Swift 5.9
   /// compiler for the target platform.
-  AvailabilityContext getSwift59Availability();
+  inline AvailabilityContext getSwift59Availability() const {
+    return getSwiftAvailability(5, 9);
+  }
 
-  /// Get the runtime availability of features introduced in the Swift 5.9
+  /// Get the runtime availability of features introduced in the Swift 5.10
   /// compiler for the target platform.
-  AvailabilityContext getSwift511Availability();
-
-  // Note: Update this function if you add a new getSwiftXYAvailability above.
-  /// Get the runtime availability for a particular version of Swift (5.0+).
-  AvailabilityContext
-  getSwift5PlusAvailability(llvm::VersionTuple swiftVersion);
+  inline AvailabilityContext getSwift510Availability() const {
+    return getSwiftAvailability(5, 10);
+  }
 
-  /// Get the runtime availability of features that have been introduced in the
-  /// Swift compiler for future versions of the target platform.
-  AvailabilityContext getSwiftFutureAvailability();
+  /// Get the runtime availability of features introduced in the Swift 5.11
+  /// compiler for the target platform.
+  inline AvailabilityContext getSwift511Availability() const {
+    return getSwiftAvailability(5, 11);
+  }
 
-  /// Returns `true` if versioned availability annotations are supported for the
-  /// target triple.
-  bool supportsVersionedAvailability() const;
+  /// Get the runtime availability for a particular version of Swift (5.0+).
+  inline AvailabilityContext
+  getSwift5PlusAvailability(llvm::VersionTuple swiftVersion) const {
+    return getSwiftAvailability(swiftVersion.getMajor(),
+                                *swiftVersion.getMinor());
+  }
+
+  /// Get the runtime availability of getters and setters of multi payload enum
+  /// tag single payloads.
+  inline AvailabilityContext getMultiPayloadEnumTagSinglePayload() const {
+    // This didn't fit the pattern, so needed renaming
+    return getMultiPayloadEnumTagSinglePayloadAvailability();
+  }
 
   //===--------------------------------------------------------------------===//
   // Diagnostics Helper functions

include/swift/AST/Availability.h

@@ -238,11 +238,15 @@ class AvailabilityContext {
 
   /// Creates a context that imposes the constraints of the ASTContext's
   /// deployment target.
-  static AvailabilityContext forDeploymentTarget(ASTContext &Ctx);
+  static AvailabilityContext forDeploymentTarget(const ASTContext &Ctx);
 
   /// Creates a context that imposes the constraints of the ASTContext's
   /// inlining target (i.e. minimum inlining version).
-  static AvailabilityContext forInliningTarget(ASTContext &Ctx);
+  static AvailabilityContext forInliningTarget(const ASTContext &Ctx);
+
+  /// Creates a context that imposes the constraints of the ASTContext's
+  /// minimum runtime version.
+  static AvailabilityContext forRuntimeTarget(const ASTContext &Ctx);
 
   /// Creates a context that imposes no constraints.
   ///

include/swift/AST/FeatureAvailability.def

@@ -0,0 +1,68 @@
+//===--- FeatureAvailability.def - Availability Metaprogramming -*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2014 - 2017 Apple Inc. and the Swift project authors
+// Licensed under Apache License v2.0 with Runtime Library Exception
+//
+// See https://swift.org/LICENSE.txt for license information
+// See https://swift.org/CONTRIBUTORS.txt for the list of Swift project authors
+//
+//===----------------------------------------------------------------------===//
+//
+// This file defines macros used for macro-metaprogramming with feature
+// availability.
+//
+//===----------------------------------------------------------------------===//
+
+/// FEATURE(N, V)
+///   N - The name of the feature (in UpperCamelCase).
+///   V - The Swift version number, as a tuple, or FUTURE.
+#ifndef FEATURE
+#define FEATURE(N, V)
+#endif
+
+/// FUTURE
+///
+/// The version to use for future support.
+#ifndef FUTURE
+#define FUTURE (99, 99)
+#endif
+
+FEATURE(ObjCMetadataUpdateCallback,                     (5, 0))
+FEATURE(ObjCGetClassHook,                               (5, 0))
+
+FEATURE(OpaqueType,                                     (5, 1))
+FEATURE(ObjCClassStubs,                                 (5, 1))
+FEATURE(BackDeployedConcurrency,                        (5, 1))
+
+FEATURE(TypesInAbstractMetadataState,                   (5, 2))
+
+FEATURE(PrespecializedGenericMetadata,                  (5, 4))
+FEATURE(CompareTypeContextDescriptors,                  (5, 4))
+FEATURE(CompareProtocolConformanceDescriptors,          (5, 4))
+FEATURE(IntermodulePrespecializedGenericMetadata,       (5, 4))
+
+FEATURE(Concurrency,                                    (5, 5))
+
+FEATURE(MultiPayloadEnumTagSinglePayload,               (5, 6))
+FEATURE(ObjCIsUniquelyReferenced,                       (5, 6))
+
+FEATURE(ParameterizedExistentialRuntime,                (5, 7))
+
+FEATURE(VariadicGenericType,                            (5, 9))
+FEATURE(SignedConformsToProtocol,                       (5, 9))
+FEATURE(ConcurrencyDiscardingTaskGroup,                 (5, 9))
+FEATURE(ConcurrencyDistributedActorWithCustomExecutor,  (5, 9))
+FEATURE(SignedDescriptor,                               (5, 9))
+
+FEATURE(ObjCSymbolicReferences,                         (5, 11))
+FEATURE(TypedThrows,                                    (5, 11))
+FEATURE(StaticReadOnlyArrays,                           (5, 11))
+
+FEATURE(TaskExecutor,                                   FUTURE)
+FEATURE(Differentiation,                                FUTURE)
+FEATURE(InitRawStructMetadata,                          FUTURE)
+
+#undef FEATURE
+#undef FUTURE