[NFC] Basic: Garden the feature infrastructure a bit

include/swift/Basic/Features.def

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2021 - 2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2021 - 2025 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
@@ -78,7 +78,7 @@
 // A feature that's both suppressible and upcoming.
 // Delegates to whichever the includer defines.
 #ifndef SUPPRESSIBLE_UPCOMING_FEATURE
-#  if defined(SUPPRESSIBLE_UPCOMING_FEATURE) && \
+#  if defined(SUPPRESSIBLE_LANGUAGE_FEATURE) && \
       defined(UPCOMING_FEATURE)
 #    error ambiguous defines when including Features.def
 #  elif defined(SUPPRESSIBLE_LANGUAGE_FEATURE)

lib/Basic/CMakeLists.txt

@@ -52,6 +52,7 @@ add_swift_host_library(swiftBasic STATIC
   Edit.cpp
   EditorPlaceholder.cpp
   ExponentialGrowthAppendingBinaryByteStream.cpp
+  Feature.cpp
   FileSystem.cpp
   FileTypes.cpp
   Fingerprint.cpp

lib/Basic/Feature.cpp

@@ -0,0 +1,84 @@
+//===--- Feature.cpp --------------------------------------------*- C++ -*-===//
+//
+// This source file is part of the Swift.org open source project
+//
+// Copyright (c) 2025 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
+//
+//===----------------------------------------------------------------------===//
+
+#include "swift/Basic/Feature.h"
+#include "llvm/ADT/StringSwitch.h"
+#include "llvm/Support/ErrorHandling.h"
+
+using namespace swift;
+
+bool swift::isFeatureAvailableInProduction(Feature feature) {
+  switch (feature) {
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
+  case Feature::FeatureName:                                                   \
+    return true;
+#define EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)                     \
+  case Feature::FeatureName:                                                   \
+    return AvailableInProd;
+#include "swift/Basic/Features.def"
+  }
+  llvm_unreachable("covered switch");
+}
+
+llvm::StringRef swift::getFeatureName(Feature feature) {
+  switch (feature) {
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
+  case Feature::FeatureName:                                                   \
+    return #FeatureName;
+#include "swift/Basic/Features.def"
+  }
+  llvm_unreachable("covered switch");
+}
+
+std::optional<Feature> swift::getUpcomingFeature(llvm::StringRef name) {
+  return llvm::StringSwitch<std::optional<Feature>>(name)
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)
+#define UPCOMING_FEATURE(FeatureName, SENumber, Version)                       \
+  .Case(#FeatureName, Feature::FeatureName)
+#include "swift/Basic/Features.def"
+      .Default(std::nullopt);
+}
+
+std::optional<Feature> swift::getExperimentalFeature(llvm::StringRef name) {
+  return llvm::StringSwitch<std::optional<Feature>>(name)
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)
+#define EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd)                     \
+  .Case(#FeatureName, Feature::FeatureName)
+#include "swift/Basic/Features.def"
+      .Default(std::nullopt);
+}
+
+std::optional<unsigned> swift::getFeatureLanguageVersion(Feature feature) {
+  switch (feature) {
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)
+#define UPCOMING_FEATURE(FeatureName, SENumber, Version)                       \
+  case Feature::FeatureName:                                                   \
+    return Version;
+#include "swift/Basic/Features.def"
+  default:
+    return std::nullopt;
+  }
+}
+
+bool swift::includeInModuleInterface(Feature feature) {
+  switch (feature) {
+#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
+  case Feature::FeatureName:                                                   \
+    return true;
+#define EXPERIMENTAL_FEATURE_EXCLUDED_FROM_MODULE_INTERFACE(FeatureName,       \
+                                                            AvailableInProd)   \
+  case Feature::FeatureName:                                                   \
+    return false;
+#include "swift/Basic/Features.def"
+  }
+  llvm_unreachable("covered switch");
+}

lib/Basic/LangOptions.cpp

@@ -2,7 +2,7 @@
 //
 // This source file is part of the Swift.org open source project
 //
-// Copyright (c) 2014 - 2023 Apple Inc. and the Swift project authors
+// Copyright (c) 2014 - 2025 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
@@ -620,75 +620,6 @@ std::pair<bool, bool> LangOptions::setTarget(llvm::Triple triple) {
   return { false, false };
 }
 
-llvm::StringRef swift::getFeatureName(Feature feature) {
-  switch (feature) {
-#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
-  case Feature::FeatureName:                                                   \
-    return #FeatureName;
-#include "swift/Basic/Features.def"
-  }
-  llvm_unreachable("covered switch");
-}
-
-bool swift::isFeatureAvailableInProduction(Feature feature) {
-  switch (feature) {
-#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
-  case Feature::FeatureName:                                                   \
-    return true;
-#define EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd) \
-  case Feature::FeatureName: return AvailableInProd;
-#define OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Description) \
-  LANGUAGE_FEATURE(FeatureName, SENumber, Description)
-#include "swift/Basic/Features.def"
-  }
-  llvm_unreachable("covered switch");
-}
-
-std::optional<Feature> swift::getUpcomingFeature(llvm::StringRef name) {
-  return llvm::StringSwitch<std::optional<Feature>>(name)
-#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)
-#define UPCOMING_FEATURE(FeatureName, SENumber, Version) \
-                   .Case(#FeatureName, Feature::FeatureName)
-#include "swift/Basic/Features.def"
-      .Default(std::nullopt);
-}
-
-std::optional<Feature> swift::getExperimentalFeature(llvm::StringRef name) {
-  return llvm::StringSwitch<std::optional<Feature>>(name)
-#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)
-#define EXPERIMENTAL_FEATURE(FeatureName, AvailableInProd) \
-                   .Case(#FeatureName, Feature::FeatureName)
-#define OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Description)
-#include "swift/Basic/Features.def"
-      .Default(std::nullopt);
-}
-
-std::optional<unsigned> swift::getFeatureLanguageVersion(Feature feature) {
-  switch (feature) {
-#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)
-#define UPCOMING_FEATURE(FeatureName, SENumber, Version) \
-  case Feature::FeatureName: return Version;
-#define OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Description)
-#include "swift/Basic/Features.def"
-  default:
-    return std::nullopt;
-  }
-}
-
-bool swift::includeInModuleInterface(Feature feature) {
-  switch (feature) {
-#define LANGUAGE_FEATURE(FeatureName, SENumber, Description)                   \
-  case Feature::FeatureName:                                                   \
-    return true;
-#define EXPERIMENTAL_FEATURE_EXCLUDED_FROM_MODULE_INTERFACE(FeatureName, AvailableInProd) \
-  case Feature::FeatureName: return false;
-#define OPTIONAL_LANGUAGE_FEATURE(FeatureName, SENumber, Description) \
-  LANGUAGE_FEATURE(FeatureName, SENumber, Description)
-#include "swift/Basic/Features.def"
-  }
-  llvm_unreachable("covered switch");
-}
-
 llvm::StringRef swift::getPlaygroundOptionName(PlaygroundOption option) {
   switch (option) {
 #define PLAYGROUND_OPTION(OptionName, Description, DefaultOn, HighPerfOn) \