From d45027b9e9497fb22da87a14593cb7dc497d12d9 Mon Sep 17 00:00:00 2001
From: Guillaume Lessard <guillaume.lessard@apple.com>
Date: Thu, 31 Aug 2023 13:53:30 -0700
Subject: [PATCH 1/3] =?UTF-8?q?adopt=20the=20stdlib=E2=80=99s=20pattern=20?=
 =?UTF-8?q?for=20atomic=20lazy=20references?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

- avoids reliance on a pointer conversion
---
 Sources/_StringProcessing/Regex/Core.swift | 19 ++++++++++++++-----
 1 file changed, 14 insertions(+), 5 deletions(-)

diff --git a/Sources/_StringProcessing/Regex/Core.swift b/Sources/_StringProcessing/Regex/Core.swift
index 5940fd500..aa4a99207 100644
--- a/Sources/_StringProcessing/Regex/Core.swift
+++ b/Sources/_StringProcessing/Regex/Core.swift
@@ -126,6 +126,13 @@ extension Regex {
   /// A program representation that caches any lowered representation for
   /// execution.
   internal final class Program {
+
+    // This stored property should be stored at offset zero.  We perform atomic
+    // operations on it.
+    //
+    /// Do not access this property directly - all accesses must go through `loweredProgram`.
+    fileprivate var _loweredProgramStorage: AnyObject? = nil
+
     /// The underlying IR.
     ///
     /// FIXME: If Regex is the unit of composition, then it should be a Node instead,
@@ -141,14 +148,16 @@ extension Regex {
       init(_ value: MEProgram) { self.value = value }
     }
 
-    /// Do not use directly - all accesses must go through `loweredProgram`.
-    fileprivate var _loweredProgramStorage: AnyObject? = nil
-    
+    fileprivate var _loweredProgramStoragePtr: UnsafeMutablePointer<AnyObject?> {
+      _getUnsafePointerToStoredProperties(self)
+        .assumingMemoryBound(to: Optional<AnyObject>.self)
+    }
+
     /// The program for execution with the matching engine.
     var loweredProgram: MEProgram {
       /// Atomically loads the compiled program if it has already been stored.
       func loadProgram() -> MEProgram? {
-        guard let loweredObject = _stdlib_atomicLoadARCRef(object: &_loweredProgramStorage)
+        guard let loweredObject = _stdlib_atomicLoadARCRef(object: _loweredProgramStoragePtr)
           else { return nil }
         return unsafeDowncast(loweredObject, to: ProgramBox.self).value
       }
@@ -161,7 +170,7 @@ extension Regex {
       // Compile the DSLTree into a lowered program and store it atomically.
       let compiledProgram = try! Compiler(tree: tree, compileOptions: compileOptions).emit()
       let storedNewProgram = _stdlib_atomicInitializeARCRef(
-        object: &_loweredProgramStorage,
+        object: _loweredProgramStoragePtr,
         desired: ProgramBox(compiledProgram))
       
       // Return the winner of the storage race. We're guaranteed at this point

From 74637cc6ae6735b2f44148fcb397f58d69dfdc97 Mon Sep 17 00:00:00 2001
From: Guillaume Lessard <guillaume.lessard@apple.com>
Date: Thu, 31 Aug 2023 13:54:56 -0700
Subject: [PATCH 2/3] pass a pointer instead of inout conversion

- this function is imported in a way that causes the compiler to not detect it as a C function
---
 Sources/_StringProcessing/Unicode/ScalarProps.swift | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/Sources/_StringProcessing/Unicode/ScalarProps.swift b/Sources/_StringProcessing/Unicode/ScalarProps.swift
index f5d9b5966..8864fd459 100644
--- a/Sources/_StringProcessing/Unicode/ScalarProps.swift
+++ b/Sources/_StringProcessing/Unicode/ScalarProps.swift
@@ -29,8 +29,10 @@ extension Unicode.Script {
   
   static func extensions(for scalar: Unicode.Scalar) -> [Unicode.Script] {
     var count: UInt8 = 0
-    let pointer = _swift_string_processing_getScriptExtensions(scalar.value, &count)
-    
+    let pointer = withUnsafeMutablePointer(to: &count) {
+      _swift_string_processing_getScriptExtensions(scalar.value, $0)
+    }
+
     guard let pointer = pointer else {
       return [Unicode.Script(scalar)]
     }

From bc7042312a0cda5440e5d8f46e3216221107f79b Mon Sep 17 00:00:00 2001
From: Guillaume Lessard <glessard@users.noreply.github.com>
Date: Thu, 31 Aug 2023 15:39:28 -0700
Subject: [PATCH 3/3] Update Sources/_StringProcessing/Regex/Core.swift

comment spelling fix
---
 Sources/_StringProcessing/Regex/Core.swift | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/Sources/_StringProcessing/Regex/Core.swift b/Sources/_StringProcessing/Regex/Core.swift
index aa4a99207..78b8d1842 100644
--- a/Sources/_StringProcessing/Regex/Core.swift
+++ b/Sources/_StringProcessing/Regex/Core.swift
@@ -130,7 +130,7 @@ extension Regex {
     // This stored property should be stored at offset zero.  We perform atomic
     // operations on it.
     //
-    /// Do not access this property directly - all accesses must go through `loweredProgram`.
+    /// Do not access this property directly - all accesses must go through `_loweredProgramStoragePtr `.
     fileprivate var _loweredProgramStorage: AnyObject? = nil
 
     /// The underlying IR.