Merge pull request #81062 from atrick/62-rdar147500193-vector-expectEquals

[6.2] Fix LifetimeDependenceDiagnostics: handle address-only 'let's

Author: atrick

SwiftCompilerSources/Sources/Optimizer/Utilities/LifetimeDependenceUtils.swift

@@ -279,10 +279,18 @@ extension LifetimeDependence.Scope {
     case let .box(projectBox):
       // Note: the box may be in a borrow scope.
       self.init(base: projectBox.operand.value, context)
-    case .stack, .class, .tail, .pointer, .index:
+    case .class, .tail, .pointer, .index:
       self = .unknown(accessBase.address!)
     case .unidentified:
       self = .unknown(address)
+    case let .stack(allocStack):
+      if let initializer = accessBase.findSingleInitializer(context) {
+        if case let .store(store, _) = initializer {
+          self = .initialized(.store(initializingStore: store, initialAddress: allocStack))
+          return
+        }
+      }
+      self = .unknown(allocStack)
     case .global:
       // TODO: When AccessBase directly stores GlobalAccessBase, we don't need a check here and don't need to pass
       // 'address' in to this function.
@@ -402,6 +410,17 @@ extension LifetimeDependence.Scope {
   ///
   /// Returns nil if the dependence scope covers the entire function. Returns an empty range for an unknown scope.
   ///
+  /// Ignore the lifetime of temporary trivial values (with .initialized and .unknown scopes). Temporaries have an
+  /// unknown Scope, which means that LifetimeDependence.Scope did not recognize a VariableScopeInstruction. This is
+  /// important to promote mark_dependence instructions emitted by SILGen to [nonescaping] (e.g. unsafeAddressor). It
+  /// also allows trivial value to be "extended" without actually tracking their scope, which is expected behavior. For
+  /// example:
+  ///
+  ///     let span = Span(buffer.baseAddress)
+  ///
+  /// If 'baseAddress' is an opaque getter, then the temporary pointer is effectively valid
+  /// until the end of the function.
+  ///
   /// Note: The caller must deinitialize the returned range.
   func computeRange(_ context: Context) -> InstructionRange? {
     switch self {
@@ -439,18 +458,13 @@ extension LifetimeDependence.Scope {
       if case let .argument(arg) = initializer, arg.convention.isInout {
         return nil
       }
+      let address = initializer.initialAddress
+      if address.type.objectType.isTrivial(in: address.parentFunction) {
+        return nil
+      }
       return LifetimeDependence.Scope.computeInitializedRange(initializer: initializer, context)
     case let .unknown(value):
-      // Ignore the lifetime of temporary trivial values. Temporaries have an unknown Scope, which means that
-      // LifetimeDependence.Scope did not recognize a VariableScopeInstruction. This is important to promote
-      // mark_dependence instructions emitted by SILGen to [nonescaping] (e.g. unsafeAddressor). It also allows trivial
-      // value to be "extended" without actually tracking their scope, which is expected behavior. For example:
-      //
-      //     let span = Span(buffer.baseAddress)
-      //
-      // If 'baseAddress' is an opaque getter, then the temporary pointer is effectively valid
-      // until the end of the function.
-      if value.type.isTrivial(in: value.parentFunction) {
+      if value.type.objectType.isTrivial(in: value.parentFunction) {
         return nil
       }
       // Return an empty range.

test/Interop/Cxx/stdlib/use-std-vector.swift

@@ -194,15 +194,12 @@ StdVectorTestSuite.test("VectorOfInt to span").require(.stdlib_6_2).code {
   guard #available(SwiftStdlib 6.2, *) else { return }
 
   let v = Vector([1, 2, 3])
-  // FIXME: remove 'withExtendedLifetime' once lifetime analysis is fixed.
-  withExtendedLifetime(v) {
-    let s = $0.span
-    expectEqual(s.count, 3)
-    expectFalse(s.isEmpty)
-    expectEqual(s[0], 1)
-    expectEqual(s[1], 2)
-    expectEqual(s[2], 3)
-  }
+  let s = v.span
+  expectEqual(s.count, 3)
+  expectFalse(s.isEmpty)
+  expectEqual(s[0], 1)
+  expectEqual(s[1], 2)
+  expectEqual(s[2], 3)
 }
 
 runAllTests()

test/SILOptimizer/lifetime_dependence/verify_diagnostics.sil

@@ -33,6 +33,10 @@ public struct Holder {
   var c: C
 }
 
+public struct TrivialHolder {
+  var p: Builtin.RawPointer
+}
+
 struct A {}
 
 struct NCWrapper : ~Copyable, ~Escapable {
@@ -44,7 +48,13 @@ sil @getNEPointer : $@convention(thin) (@guaranteed NE) -> Builtin.RawPointer
 sil @useA : $@convention(thin) (A) -> ()
 sil @makeNE : $@convention(thin) () -> @lifetime(immortal) @owned NE
 sil @makeNEObject : $@convention(thin) () -> @lifetime(immortal) @owned NEObject
-sil @useNE : $@convention(thin) (NE) -> ()
+sil @useNE : $@convention(thin) (@guaranteed NE) -> ()
+
+sil @initHolder : $@convention(thin) () -> @out Holder
+sil @getNE : $@convention(thin) (@in_guaranteed Holder) -> @lifetime(borrow address_for_deps 0) @owned NE
+
+sil @initTrivialHolder : $@convention(thin) () -> @out TrivialHolder
+sil @getTrivialNE : $@convention(thin) (@in_guaranteed TrivialHolder) -> @lifetime(borrow address_for_deps 0) @owned NE
 
 // Test returning a owned dependence on a trivial value
 sil [ossa] @return_trivial_dependence : $@convention(thin) (@guaranteed C) -> @lifetime(borrow 0) @owned NE {
@@ -80,8 +90,8 @@ bb0(%0 : @owned $Holder):
   %c1 = apply %f1() : $@convention(thin) () -> @lifetime(immortal) @owned NE
   %md = mark_dependence [unresolved] %c1 on %sb
   %mv = move_value [var_decl] %md
-  %f2 = function_ref @useNE : $@convention(thin) (NE) -> ()
-  %c2 = apply %f2(%mv) : $@convention(thin) (NE) -> ()
+  %f2 = function_ref @useNE : $@convention(thin) (@guaranteed NE) -> ()
+  %c2 = apply %f2(%mv) : $@convention(thin) (@guaranteed NE) -> ()
   destroy_value %mv
   end_borrow %sb
   dealloc_stack %stk
@@ -115,3 +125,41 @@ bb0(%0 : @owned $NCWrapper):
   %17 = tuple ()
   return %17
 }
+
+// Test that LifetimeDependence.Scope recognizes a singly-initialized alloc_stack.
+sil [ossa] @testStackInit : $@convention(thin) () -> () {
+bb0:
+  %0 = alloc_stack [lexical] [var_decl] $Holder, let, name "v"
+  %1 = function_ref @initHolder : $@convention(thin) () -> @out Holder
+  %2 = apply %1(%0) : $@convention(thin) () -> @out Holder
+  %3 = function_ref @getNE : $@convention(thin) (@in_guaranteed Holder) -> @lifetime(borrow address_for_deps 0) @owned NE
+  %4 = apply %3(%0) : $@convention(thin) (@in_guaranteed Holder) -> @lifetime(borrow address_for_deps 0) @owned NE
+  %5 = mark_dependence [unresolved] %4 on %0
+  %6 = move_value [var_decl] %5
+  %7 = function_ref @useNE : $@convention(thin) (@guaranteed NE) -> ()
+  %8 = apply %7(%6) : $@convention(thin) (@guaranteed NE) -> ()
+  destroy_value %6
+  destroy_addr %0
+  dealloc_stack %0
+  %12 = tuple ()
+  return %12
+}
+
+// Test that LifetimeDependence.Scope.computeRange handles a singly-initialized alloc_stack of trivial type by treating
+// it as available for the entire function
+sil [ossa] @testTrivialStackInit : $@convention(thin) () -> () {
+bb0:
+  %0 = alloc_stack [lexical] [var_decl] $TrivialHolder, let, name "v"
+  %1 = function_ref @initTrivialHolder : $@convention(thin) () -> @out TrivialHolder
+  %2 = apply %1(%0) : $@convention(thin) () -> @out TrivialHolder
+  %3 = function_ref @getTrivialNE : $@convention(thin) (@in_guaranteed TrivialHolder) -> @lifetime(borrow 0) @owned NE
+  %4 = apply %3(%0) : $@convention(thin) (@in_guaranteed TrivialHolder) -> @lifetime(borrow 0) @owned NE
+  %5 = mark_dependence [unresolved] %4 on %0
+  dealloc_stack %0
+  %6 = move_value [var_decl] %5
+  %7 = function_ref @useNE : $@convention(thin) (@guaranteed NE) -> ()
+  %8 = apply %7(%6) : $@convention(thin) (@guaranteed NE) -> ()
+  destroy_value %6
+  %12 = tuple ()
+  return %12
+}