[Debugging] Add DebugDescriptionMacro experimental feature (#73070)

This removes the leading underscore from the macro.

Author: kastiglione

include/swift/Basic/Features.def

@@ -376,6 +376,9 @@ EXPERIMENTAL_FEATURE(ObjCImplementation, true)
 // Enable @implementation on @_cdecl functions.
 EXPERIMENTAL_FEATURE(CImplementation, true)
 
+// Enable the stdlib @DebugDescription macro.
+EXPERIMENTAL_FEATURE(DebugDescriptionMacro, false)
+
 #undef EXPERIMENTAL_FEATURE_EXCLUDED_FROM_MODULE_INTERFACE
 #undef EXPERIMENTAL_FEATURE
 #undef UPCOMING_FEATURE

lib/AST/FeatureSet.cpp

@@ -686,6 +686,8 @@ UNINTERESTING_FEATURE(IsolatedAny2)
 UNINTERESTING_FEATURE(ObjCImplementation)
 UNINTERESTING_FEATURE(CImplementation)
 
+UNINTERESTING_FEATURE(DebugDescriptionMacro)
+
 // ----------------------------------------------------------------------------
 // MARK: - FeatureSet
 // ----------------------------------------------------------------------------

lib/Frontend/CompilerInvocation.cpp

@@ -1513,6 +1513,10 @@ static bool ParseLangArgs(LangOptions &Opts, ArgList &Args,
     }
   }
 
+  // @DebugDescription uses @_section and @_used attributes.
+  if (Opts.hasFeature(Feature::DebugDescriptionMacro))
+    Opts.enableFeature(Feature::SymbolLinkageMarkers);
+
 #if SWIFT_ENABLE_EXPERIMENTAL_PARSER_VALIDATION
   /// Enable round trip parsing via the new swift parser unless it is disabled
   /// explicitly. The new Swift parser can have mismatches with C++ parser -

stdlib/public/core/CMakeLists.txt

@@ -328,7 +328,7 @@ endif()
 
 list(APPEND swift_stdlib_compile_flags "-external-plugin-path"
   "${swift_lib_dir}/swift/host/plugins#${swift_bin_dir}/swift-plugin-server")
-list(APPEND swift_stdlib_compile_flags "-enable-experimental-feature" "SymbolLinkageMarkers")
+list(APPEND swift_stdlib_compile_flags "-enable-experimental-feature" "DebugDescriptionMacro")
 
 set(swift_core_incorporate_object_libraries)
 list(APPEND swift_core_incorporate_object_libraries swiftRuntime)

stdlib/public/core/DebuggerSupport.swift

@@ -13,7 +13,7 @@
 import SwiftShims
 
 // Macros are disabled when Swift is built without swift-syntax.
-#if $Macros && hasAttribute(attached)
+#if $Macros && $DebugDescriptionMacro && hasAttribute(attached)
 
 /// Converts description definitions to a debugger Type Summary.
 ///
@@ -65,10 +65,10 @@ import SwiftShims
 ///   logic and computed properties are not supported.
 /// * Overloaded string interpolation cannot be used.
 @attached(memberAttribute)
-public macro _DebugDescription() =
+public macro DebugDescription() =
   #externalMacro(module: "SwiftMacros", type: "DebugDescriptionMacro")
 
-/// Internal-only macro. See `@_DebugDescription`.
+/// Internal-only macro. See `@DebugDescription`.
 @attached(peer, names: named(_lldb_summary))
 public macro _DebugDescriptionProperty(_ debugIdentifier: String, _ computedProperties: [String]) =
   #externalMacro(module: "SwiftMacros", type: "_DebugDescriptionPropertyMacro")

stdlib/public/core/ObjectIdentifier+DebugDescription.swift

@@ -11,7 +11,7 @@
 //===----------------------------------------------------------------------===//
 
 #if !$Embedded
-@_DebugDescription
+@DebugDescription
 extension ObjectIdentifier {
   var _debugDescription: String {
     return "ObjectIdentifier(\(_value))"

test/Macros/DebugDescription/error_complex_implementation.swift

@@ -3,7 +3,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend %s -swift-version 5 -module-name main -disable-availability-checking -typecheck -verify -plugin-path %swift-plugin-dir
 
-@_DebugDescription
+@DebugDescription
 struct MyStruct {
   var flag: Bool
 

test/Macros/DebugDescription/error_computed_properties.swift

@@ -3,7 +3,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend %s -swift-version 5 -module-name main -disable-availability-checking -typecheck -verify -plugin-path %swift-plugin-dir
 
-@_DebugDescription
+@DebugDescription
 struct MyStruct {
   var name: String { "thirty" }
 

test/Macros/DebugDescription/error_custom_interpolation.swift

@@ -8,13 +8,13 @@ extension DefaultStringInterpolation {
   fileprivate func appendInterpolation<A, B>(_ a: A, _ b: B) {}
 }
 
-@_DebugDescription
+@DebugDescription
 struct MyStruct1 {
   // expected-error @+1 {{unsupported custom string interpolation expression}}
   var debugDescription: String { "\(custom: 30)" }
 }
 
-@_DebugDescription
+@DebugDescription
 struct MyStruct2 {
   // expected-error @+1 {{unsupported custom string interpolation expression}}
   var debugDescription: String { "\(30, true)" }

test/Macros/DebugDescription/error_interpolation_expression.swift

@@ -3,7 +3,7 @@
 // RUN: %empty-directory(%t)
 // RUN: %target-swift-frontend %s -swift-version 5 -module-name main -disable-availability-checking -typecheck -verify -plugin-path %swift-plugin-dir
 
-@_DebugDescription
+@DebugDescription
 struct MyStruct {
   // expected-error @+1 {{only references to stored properties are allowed}}
   var debugDescription: String { "\(1)" }