Merge pull request #78283 from atrick/remove-trivial-feature

Remove the experimental LifetimeDependenceDiagnoseTrivial feature.
swiftlang · Dec 19, 2024 · c347b66 · c347b66
2 parents a3d9776 + 5581ab8
commit c347b66
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Showing 44 changed files with 91 additions and 100 deletions.
diff --git a/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceDiagnostics.swift b/SwiftCompilerSources/Sources/Optimizer/FunctionPasses/LifetimeDependenceDiagnostics.swift
@@ -101,10 +101,11 @@ let lifetimeDependenceDiagnosticsPass = FunctionPass(
 private func analyze(dependence: LifetimeDependence, _ context: FunctionPassContext) -> Bool {
   log("Dependence scope:\n\(dependence)")
 
-  // Early versions of Span in the standard library violate trivial lifetimes. Contemporary versions of the compiler
-  // simply ignored dependencies on trivial values.
-  if !context.options.hasFeature(.LifetimeDependenceDiagnoseTrivial) {
-    if dependence.parentValue.type.objectType.isTrivial(in: dependence.function) {
+  // Briefly, some versions of Span in the standard library violated trivial lifetimes; versions of the compiler built
+  // at that time simply ignored dependencies on trivial values. For now, disable trivial dependencies to allow newer
+  // compilers to build against those older standard libraries. This check is only relevant for ~6 mo (until July 2025).
+  if dependence.parentValue.type.objectType.isTrivial(in: dependence.function) {
+    if let sourceFileKind = dependence.function.sourceFileKind, sourceFileKind == .interface {
       return true
     }
   }

diff --git a/SwiftCompilerSources/Sources/SIL/Function.swift b/SwiftCompilerSources/Sources/SIL/Function.swift
@@ -256,6 +256,27 @@ final public class Function : CustomStringConvertible, HasShortDescription, Hash
         fatalError()
     }
   }
+
+  public enum SourceFileKind {
+    case library         /// A normal .swift file.
+    case main            /// A .swift file that can have top-level code.
+    case sil             /// Came from a .sil file.
+    case interface       /// Came from a .swiftinterface file, representing another module.
+    case macroExpansion  /// Came from a macro expansion.
+    case defaultArgument /// Came from default argument at caller side
+  };
+
+  public var sourceFileKind: SourceFileKind? {
+    switch bridged.getSourceFileKind() {
+    case .Library: return .library
+    case .Main: return .main
+    case .SIL: return .sil
+    case .Interface: return .interface
+    case .MacroExpansion: return .macroExpansion
+    case .DefaultArgument: return .defaultArgument
+    case .None: return nil
+    }
+  }
 }
 
 public func == (lhs: Function, rhs: Function) -> Bool { lhs === rhs }

diff --git a/include/swift/Basic/Features.def b/include/swift/Basic/Features.def
@@ -362,9 +362,6 @@ EXPERIMENTAL_FEATURE(StructLetDestructuring, true)
 /// Enable returning non-escapable types from functions.
 EXPERIMENTAL_FEATURE(LifetimeDependence, true)
 
-/// Enable LifetimeDependence diagnostics for trivial types.
-EXPERIMENTAL_FEATURE(LifetimeDependenceDiagnoseTrivial, false)
-
 /// Enable the `@_staticExclusiveOnly` attribute.
 EXPERIMENTAL_FEATURE(StaticExclusiveOnly, true)
 

diff --git a/include/swift/SIL/SILBridging.h b/include/swift/SIL/SILBridging.h
@@ -477,6 +477,16 @@ struct BridgedFunction {
     IsSerializedForPackage
   };
 
+  enum class OptionalSourceFileKind {
+    Library,
+    Main,
+    SIL,
+    Interface,
+    MacroExpansion,
+    DefaultArgument, // must match swift::SourceFileKind::DefaultArgument
+    None
+  };
+
   SWIFT_NAME("init(obj:)")
   BridgedFunction(SwiftObject obj) : obj(obj) {}
   BridgedFunction() {}
@@ -529,6 +539,7 @@ struct BridgedFunction {
   bool isAutodiffVJP() const;
   SwiftInt specializationLevel() const;
   SWIFT_IMPORT_UNSAFE BridgedSubstitutionMap getMethodSubstitutions(BridgedSubstitutionMap contextSubs) const;
+  BRIDGED_INLINE OptionalSourceFileKind getSourceFileKind() const;
 
   enum class ParseEffectsMode {
     argumentEffectsFromSource,

diff --git a/include/swift/SIL/SILBridgingImpl.h b/include/swift/SIL/SILBridgingImpl.h
@@ -22,6 +22,7 @@
 #include "SILBridging.h"
 #include "swift/AST/Builtins.h"
 #include "swift/AST/Decl.h"
+#include "swift/AST/SourceFile.h"
 #include "swift/AST/SubstitutionMap.h"
 #include "swift/AST/Types.h"
 #include "swift/Basic/BasicBridging.h"
@@ -924,6 +925,14 @@ swift::SILFunction * _Nullable OptionalBridgedFunction::getFunction() const {
   return static_cast<swift::SILFunction *>(obj);
 }
 
+BridgedFunction::OptionalSourceFileKind BridgedFunction::getSourceFileKind() const {
+  if (auto *dc = getFunction()->getDeclContext()) {
+    if (auto *sourceFile = dc->getParentSourceFile())
+      return (OptionalSourceFileKind)sourceFile->Kind;
+  }
+  return OptionalSourceFileKind::None;
+}
+
 //===----------------------------------------------------------------------===//
 //                                BridgedGlobalVar
 //===----------------------------------------------------------------------===//

diff --git a/lib/AST/FeatureSet.cpp b/lib/AST/FeatureSet.cpp
@@ -263,8 +263,6 @@ static bool usesFeatureLifetimeDependence(Decl *decl) {
       ->hasLifetimeDependencies();
 }
 
-UNINTERESTING_FEATURE(LifetimeDependenceDiagnoseTrivial)
-
 UNINTERESTING_FEATURE(DynamicActorIsolation)
 UNINTERESTING_FEATURE(NonfrozenEnumExhaustivity)
 UNINTERESTING_FEATURE(ClosureIsolation)

diff --git a/stdlib/public/Cxx/CxxSpan.swift b/stdlib/public/Cxx/CxxSpan.swift
@@ -18,6 +18,24 @@ internal func unsafeBitCast<T: ~Escapable, U>(
   Builtin.reinterpretCast(x)
 }
 
+/// Unsafely discard any lifetime dependency on the `dependent` argument. Return
+/// a value identical to `dependent` with a lifetime dependency on the caller's
+/// borrow scope of the `source` argument.
+@unsafe
+@_unsafeNonescapableResult
+@_alwaysEmitIntoClient
+@_transparent
+@lifetime(borrow source)
+internal func _overrideLifetime<
+  T: ~Copyable & ~Escapable, U: ~Copyable & ~Escapable
+>(
+  _ dependent: consuming T, borrowing source: borrowing U
+) -> T {
+  // TODO: Remove @_unsafeNonescapableResult. Instead, the unsafe dependence
+  // should be expressed by a builtin that is hidden within the function body.
+  dependent
+}
+
 /// A C++ type that is an object that can refer to a contiguous sequence of objects.
 ///
 /// C++ standard library type `std::span` conforms to this protocol.
@@ -62,12 +80,15 @@ extension CxxSpan {
 @available(SwiftStdlib 6.1, *)
 extension Span {
   @_alwaysEmitIntoClient
-  @lifetime(immortal)
   @unsafe
+  @lifetime(borrow span)
   public init<T: CxxSpan<Element>>(
-    _unsafeCxxSpan span: T,
+    _unsafeCxxSpan span: borrowing T,
   ) {
-    self.init(_unsafeElements: .init(start: span.__dataUnsafe(), count: Int(span.size())))
+    let buffer = UnsafeBufferPointer(start: span.__dataUnsafe(), count: Int(span.size()))
+    let newSpan = Span(_unsafeElements: buffer)
+    // 'self' is limited to the caller's scope of the variable passed to the 'span' argument.
+    self = _overrideLifetime(newSpan, borrowing: span)
   }
 }
 

diff --git a/test/Generics/inverse_generics.swift b/test/Generics/inverse_generics.swift
@@ -1,10 +1,8 @@
 // RUN: %target-typecheck-verify-swift \
 // RUN: -enable-experimental-feature LifetimeDependence \
-// RUN: -enable-experimental-feature LifetimeDependenceDiagnoseTrivial \
 // RUN: -enable-experimental-feature SuppressedAssociatedTypes
 
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 // REQUIRES: swift_feature_SuppressedAssociatedTypes
 
 // expected-note@+1 {{'T' has '~Copyable' constraint preventing implicit 'Copyable' conformance}}

diff --git a/test/SIL/Parser/basic2_noncopyable_generics.sil b/test/SIL/Parser/basic2_noncopyable_generics.sil
@@ -1,16 +1,13 @@
 // RUN: %target-sil-opt                                      \
 // RUN:     %s                                               \
 // RUN:     -enable-experimental-feature LifetimeDependence   \
-// RUN:     -enable-experimental-feature LifetimeDependenceDiagnoseTrivial \
 // RUN: |                                                    \
 // RUN: %target-sil-opt                                      \
 // RUN:     -enable-experimental-feature LifetimeDependence   \
-// RUN:     -enable-experimental-feature LifetimeDependenceDiagnoseTrivial \
 // RUN: |                                                    \
 // RUN: %FileCheck %s
 
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 // For -enable-experimental-feature LifetimeDependence
 

diff --git a/test/SIL/Parser/lifetime_dependence.sil b/test/SIL/Parser/lifetime_dependence.sil
@@ -1,10 +1,8 @@
 // RUN: %target-sil-opt %s \
 // RUN:   -enable-experimental-feature LifetimeDependence \
-// RUN:   -enable-experimental-feature LifetimeDependenceDiagnoseTrivial \
 // RUN: | %FileCheck %s
 
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 sil_stage canonical
 

diff --git a/test/SIL/explicit_lifetime_dependence_specifiers.swift b/test/SIL/explicit_lifetime_dependence_specifiers.swift
@@ -2,11 +2,9 @@
 // RUN: -emit-sil  \
 // RUN: -enable-builtin-module \
 // RUN: -enable-experimental-feature LifetimeDependence \
-// RUN: -enable-experimental-feature LifetimeDependenceDiagnoseTrivial \
 // RUN: | %FileCheck %s
 
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 import Builtin
 

diff --git a/test/SIL/implicit_lifetime_dependence.swift b/test/SIL/implicit_lifetime_dependence.swift
@@ -1,11 +1,9 @@
 // RUN: %target-swift-frontend %s \
 // RUN: -emit-sil  -target %target-swift-5.1-abi-triple \
 // RUN: -enable-experimental-feature LifetimeDependence \
-// RUN: -enable-experimental-feature LifetimeDependenceDiagnoseTrivial \
 // RUN: | %FileCheck %s
 
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 @_unsafeNonescapableResult
 @lifetime(source)

diff --git a/test/SIL/lifetime_dependence_generics.swift b/test/SIL/lifetime_dependence_generics.swift
@@ -1,12 +1,10 @@
 // RUN: %target-swift-frontend %s -emit-sil \
 // RUN:   -enable-experimental-feature LifetimeDependence \
-// RUN:   -enable-experimental-feature LifetimeDependenceDiagnoseTrivial \
 // RUN:   -enable-experimental-feature SuppressedAssociatedTypes \
 // RUN: | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 // REQUIRES: swift_feature_SuppressedAssociatedTypes
 
 protocol P {

diff --git a/test/SIL/lifetime_dependence_param_position_test.swift b/test/SIL/lifetime_dependence_param_position_test.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-frontend %s -emit-silgen \
-// RUN:   -enable-experimental-feature LifetimeDependence \
-// RUN:   -enable-experimental-feature LifetimeDependenceDiagnoseTrivial
+// RUN:   -enable-experimental-feature LifetimeDependence
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 
 public struct Span<Element> : ~Escapable {

diff --git a/test/SIL/lifetime_dependence_span_lifetime_attr.swift b/test/SIL/lifetime_dependence_span_lifetime_attr.swift
@@ -1,11 +1,9 @@
 // RUN: %target-swift-frontend %s -emit-sil \
 // RUN:   -enable-experimental-feature LifetimeDependence \
-// RUN:   -enable-experimental-feature LifetimeDependenceDiagnoseTrivial \
 // RUN: | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 // TODO: Use real Range
 public struct FakeRange<Bound> {

diff --git a/test/SIL/type_lowering_unit.sil b/test/SIL/type_lowering_unit.sil
@@ -1,10 +1,8 @@
 // RUN: %target-sil-opt -test-runner \
 // RUN:   -enable-experimental-feature LifetimeDependence \
-// RUN:   -enable-experimental-feature LifetimeDependenceDiagnoseTrivial \
 // RUN:   %s -o /dev/null 2>&1 | %FileCheck %s
 
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 sil_stage raw
 

diff --git a/test/SILGen/accessor_borrow.swift b/test/SILGen/accessor_borrow.swift
@@ -1,10 +1,8 @@
 // RUN: %target-swift-emit-silgen -module-name accessor_borrow \
 // RUN: -enable-experimental-feature LifetimeDependence \
-// RUN: -enable-experimental-feature LifetimeDependenceDiagnoseTrivial \
 // RUN: %s | %FileCheck %s
 
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 struct NE: ~Escapable {}
 

diff --git a/test/SILGen/addressors.swift b/test/SILGen/addressors.swift
@@ -97,7 +97,7 @@ func test1() -> Int32 {
 // CHECK: [[PTR:%.*]] = apply [[ACCESSOR]]({{%.*}}, [[A]]) : $@convention(method) (Int32, A) -> UnsafePointer<Int32>
 // CHECK: [[T0:%.*]] = struct_extract [[PTR]] : $UnsafePointer<Int32>, #UnsafePointer._rawValue
 // CHECK: [[T1:%.*]] = pointer_to_address [[T0]] : $Builtin.RawPointer to [strict] $*Int32
-// CHECK: [[MD:%.*]] = mark_dependence [nonescaping] [[T1]] : $*Int32 on [[A]] : $A
+// CHECK: [[MD:%.*]] = mark_dependence [[T1]] : $*Int32 on [[A]] : $A
 // CHECK: [[ACCESS:%.*]] = begin_access [read] [unsafe] [[MD]] : $*Int32
 // CHECK: [[T2:%.*]] = load [[ACCESS]] : $*Int32
 // CHECK: return [[T2]] : $Int32

diff --git a/test/SILOptimizer/argument_conventions.sil b/test/SILOptimizer/argument_conventions.sil
@@ -1,12 +1,10 @@
 // RUN: %target-sil-opt -test-runner %s \
 // RUN:   -sil-verify-all \
 // RUN:   -enable-experimental-feature LifetimeDependence \
-// RUN:   -enable-experimental-feature LifetimeDependenceDiagnoseTrivial \
 // RUN:   2>&1 | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 import Builtin
 

diff --git a/test/SILOptimizer/capture_promotion_ownership.sil b/test/SILOptimizer/capture_promotion_ownership.sil
@@ -1,11 +1,9 @@
 // RUN: %target-sil-opt -sil-print-types -enable-sil-verify-all %s -capture-promotion \
 // RUN: -enable-experimental-feature LifetimeDependence \
-// RUN: -enable-experimental-feature LifetimeDependenceDiagnoseTrivial \
 // RUN: -module-name Swift \
 // RUN: | %FileCheck %s
 
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 // Check to make sure that the process of promoting closure captures results in
 // a correctly cloned and modified closure function body. This test

diff --git a/test/SILOptimizer/lifetime_dependence/coroutine.swift b/test/SILOptimizer/lifetime_dependence/coroutine.swift
@@ -1,11 +1,9 @@
 // RUN: %target-swift-frontend %s -emit-sil \
 // RUN: -enable-experimental-feature LifetimeDependence \
-// RUN: -enable-experimental-feature LifetimeDependenceDiagnoseTrivial \
 // RUN: | %FileCheck %s
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 struct View : ~Escapable {
   let ptr: UnsafeRawBufferPointer

diff --git a/test/SILOptimizer/lifetime_dependence/diagnostic_passes.sil b/test/SILOptimizer/lifetime_dependence/diagnostic_passes.sil
@@ -1,7 +1,6 @@
 // RUN: %target-sil-opt -test-runner %s \
 // RUN:     -diagnostics -sil-verify-all \
 // RUN:     -enable-experimental-feature LifetimeDependence \
-// RUN:     -enable-experimental-feature LifetimeDependenceDiagnoseTrivial \
 // RUN:     2>&1 | %FileCheck %s
 
 // Test SIL expected from SILGen output. Run all diagnostic passes which includes lifetime dependence handling:
@@ -13,7 +12,6 @@
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 sil_stage raw
 

diff --git a/test/SILOptimizer/lifetime_dependence/diagnostic_passes_todo.sil b/test/SILOptimizer/lifetime_dependence/diagnostic_passes_todo.sil
@@ -1,11 +1,9 @@
 // RUN: %target-sil-opt -test-runner %s \
 // RUN:     -diagnostics -sil-verify-all \
 // RUN:     -enable-experimental-feature LifetimeDependence \
-// RUN:     -enable-experimental-feature LifetimeDependenceDiagnoseTrivial \
 // RUN:     2>&1 | %FileCheck %s
 
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 // Test SIL expected from SILGen output. Run all diagnostic passes which includes lifetime dependence handling.
 // These tests are not fully implemented.

diff --git a/test/SILOptimizer/lifetime_dependence/initializer.swift b/test/SILOptimizer/lifetime_dependence/initializer.swift
@@ -3,12 +3,10 @@
 // RUN:   -verify \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
-// RUN:   -enable-experimental-feature LifetimeDependence \
-// RUN:   -enable-experimental-feature LifetimeDependenceDiagnoseTrivial
+// RUN:   -enable-experimental-feature LifetimeDependence
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 struct Span<T>: ~Escapable {
   private var base: UnsafePointer<T>

diff --git a/test/SILOptimizer/lifetime_dependence/inout.swift b/test/SILOptimizer/lifetime_dependence/inout.swift
@@ -3,12 +3,10 @@
 // RUN:   -verify \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name test \
-// RUN:   -enable-experimental-feature LifetimeDependence \
-// RUN:   -enable-experimental-feature LifetimeDependenceDiagnoseTrivial
+// RUN:   -enable-experimental-feature LifetimeDependence
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 struct Span<T>: ~Escapable {
   private var base: UnsafePointer<T>

diff --git a/test/SILOptimizer/lifetime_dependence/lifetime_dependence.sil b/test/SILOptimizer/lifetime_dependence/lifetime_dependence.sil
@@ -2,12 +2,10 @@
 // RUN:   -o /dev/null \
 // RUN:   -sil-verify-all \
 // RUN:   -module-name Swift \
-// RUN:   -enable-experimental-feature LifetimeDependence \
-// RUN:   -enable-experimental-feature LifetimeDependenceDiagnoseTrivial
+// RUN:   -enable-experimental-feature LifetimeDependence
 
 // REQUIRES: swift_in_compiler
 // REQUIRES: swift_feature_LifetimeDependence
-// REQUIRES: swift_feature_LifetimeDependenceDiagnoseTrivial
 
 // Test the SIL representation for lifetime dependence.