From 6c14ffcbe6118c12db0de58e85c616d88fa01edf Mon Sep 17 00:00:00 2001
From: Umberto Raimondi <me@uraimo.com>
Date: Thu, 23 Nov 2017 08:39:31 -0500
Subject: [PATCH] Improve host architecture detection

---
 CMakeLists.txt                   |  5 ++++-
 cmake/modules/SwiftSupport.cmake | 33 ++++++++++++++++++++++++++++++++
 2 files changed, 37 insertions(+), 1 deletion(-)

diff --git a/CMakeLists.txt b/CMakeLists.txt
index 5b294bba3..365add211 100644
--- a/CMakeLists.txt
+++ b/CMakeLists.txt
@@ -21,6 +21,7 @@ include(CheckIncludeFiles)
 include(CheckLibraryExists)
 include(CheckSymbolExists)
 include(GNUInstallDirs)
+include(SwiftSupport)
 
 set(INSTALL_LIBDIR "lib" CACHE PATH "Path where the libraries should be installed")
 set(WITH_BLOCKS_RUNTIME "" CACHE PATH "Path to blocks runtime")
@@ -44,7 +45,9 @@ if(ENABLE_SWIFT)
   get_filename_component(SWIFT_TOOLCHAIN ${SWIFT_TOOLCHAIN} DIRECTORY)
 
   string(TOLOWER ${CMAKE_SYSTEM_NAME} SWIFT_OS)
-  set(SWIFT_RUNTIME_LIBDIR ${SWIFT_TOOLCHAIN}/lib/swift/${SWIFT_OS}/${CMAKE_SYSTEM_PROCESSOR})
+  get_swift_host_arch(SWIFT_HOST_ARCH)
+
+  set(SWIFT_RUNTIME_LIBDIR ${SWIFT_TOOLCHAIN}/lib/swift/${SWIFT_OS}/${SWIFT_HOST_ARCH})
 
   add_library(swiftCore
               SHARED IMPORTED GLOBAL)
diff --git a/cmake/modules/SwiftSupport.cmake b/cmake/modules/SwiftSupport.cmake
index b7a3e760c..ec891d598 100644
--- a/cmake/modules/SwiftSupport.cmake
+++ b/cmake/modules/SwiftSupport.cmake
@@ -71,3 +71,36 @@ function(add_swift_library library)
                        ${ASL_MODULE_PATH}
                        ${module_directory}/${ASL_MODULE_NAME}.swiftdoc)
 endfunction()
+
+# Returns the current achitecture name in a variable
+#
+# Usage:
+#   get_swift_host_arch(result_var_name)
+#
+# If the current architecture is supported by Swift, sets ${result_var_name}
+# with the sanitized host architecture name derived from CMAKE_SYSTEM_PROCESSOR.
+function(get_swift_host_arch result_var_name)
+  if("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "x86_64")
+    set("${result_var_name}" "x86_64" PARENT_SCOPE)
+  elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "aarch64")
+    set("${result_var_name}" "aarch64" PARENT_SCOPE)
+  elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "ppc64")
+    set("${result_var_name}" "powerpc64" PARENT_SCOPE)
+  elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "ppc64le")
+    set("${result_var_name}" "powerpc64le" PARENT_SCOPE)
+  elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "s390x")
+    set("${result_var_name}" "s390x" PARENT_SCOPE)
+  elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "armv6l")
+    set("${result_var_name}" "armv6" PARENT_SCOPE)
+  elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "armv7l")
+    set("${result_var_name}" "armv7" PARENT_SCOPE)
+  elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "AMD64")
+    set("${result_var_name}" "x86_64" PARENT_SCOPE)
+  elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "IA64")
+    set("${result_var_name}" "itanium" PARENT_SCOPE)
+  elseif("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL "x86")
+    set("${result_var_name}" "i686" PARENT_SCOPE)
+  else()
+    message(FATAL_ERROR "Unrecognized architecture on host system: ${CMAKE_SYSTEM_PROCESSOR}")
+  endif()
+endfunction()