From 8682afd971b68a9c73d66417cb2ba3fca57a85c1 Mon Sep 17 00:00:00 2001
From: Evan Wilde <ewilde@apple.com>
Date: Fri, 29 May 2026 14:55:47 -0700
Subject: [PATCH] Swift: Extract pointer size from Swift compiler

The target info in Swift 6.2 and newer supports emitting the pointer
size for a given target triple. We can use that to set the Swift data
pointer size, and the `CMAKE_SIZEOF_VOID_P`.

Fixes: #26649
---
 Modules/CMakeDetermineSwiftCompiler.cmake | 4 ++++
 Modules/CMakeSwiftCompiler.cmake.in       | 5 +++++
 2 files changed, 9 insertions(+)

diff --git a/Modules/CMakeDetermineSwiftCompiler.cmake b/Modules/CMakeDetermineSwiftCompiler.cmake
index d1c09fc814..b8f69eea47 100644
--- a/Modules/CMakeDetermineSwiftCompiler.cmake
+++ b/Modules/CMakeDetermineSwiftCompiler.cmake
@@ -139,6 +139,10 @@ if(CMAKE_Swift_COMPILER_VERSION VERSION_GREATER_EQUAL 5.2)
   message(CONFIGURE_LOG "Swift target info:\n" "${swift_target_info}")
   string(JSON module_triple GET "${swift_target_info}" "target" "moduleTriple")
   set(CMAKE_Swift_MODULE_TRIPLE ${module_triple})
+
+  if(CMAKE_Swift_COMPILER_VERSION VERSION_GREATER_EQUAL 6.2)
+    string(JSON CMAKE_Swift_SIZEOF_DATA_PTR GET "${swift_target_info}" "target" "pointerWidthInBytes")
+  endif()
 endif()
 
 if (NOT _CMAKE_TOOLCHAIN_LOCATION)
diff --git a/Modules/CMakeSwiftCompiler.cmake.in b/Modules/CMakeSwiftCompiler.cmake.in
index 5e2483a02d..27139d646b 100644
--- a/Modules/CMakeSwiftCompiler.cmake.in
+++ b/Modules/CMakeSwiftCompiler.cmake.in
@@ -18,3 +18,8 @@ set(CMAKE_Swift_COMPILER_USE_OLD_DRIVER "@CMAKE_Swift_COMPILER_USE_OLD_DRIVER@")
 set(CMAKE_Swift_IMPLICIT_INCLUDE_DIRECTORIES "@CMAKE_Swift_IMPLICIT_INCLUDE_DIRECTORIES@")
 
 set(CMAKE_Swift_MODULE_TRIPLE "@CMAKE_Swift_MODULE_TRIPLE@")
+set(CMAKE_Swift_SIZEOF_DATA_PTR "@CMAKE_Swift_SIZEOF_DATA_PTR@")
+
+if(NOT CMAKE_SIZEOF_VOID_P AND CMAKE_Swift_SIZEOF_DATA_PTR)
+  set(CMAKE_SIZEOF_VOID_P "${CMAKE_Swift_SIZEOF_DATA_PTR}")
+endif()