From d3fd7510675f441c861119b625816149638abb41 Mon Sep 17 00:00:00 2001
From: Amin Yahyaabadi <aminyahyaabadi74@gmail.com>
Date: Mon, 28 Feb 2022 19:23:06 -0800
Subject: [PATCH] refactor: make detect_architecture a generic utility function

---
 src/Utilities.cmake     | 44 +++++++++++++++++++++++++++++++++++++++++
 src/VCEnvironment.cmake | 26 +-----------------------
 2 files changed, 45 insertions(+), 25 deletions(-)

diff --git a/src/Utilities.cmake b/src/Utilities.cmake
index 6fa78b28..a35b26a9 100644
--- a/src/Utilities.cmake
+++ b/src/Utilities.cmake
@@ -137,3 +137,47 @@ function(is_verbose var)
         PARENT_SCOPE)
   endif()
 endfunction()
+
+# detect the architecture of the target build system or the host system as a fallback
+function(detect_architecture arch)
+  # if the target processor is not known, fallback to the host processor
+  if("${CMAKE_SYSTEM_PROCESSOR}" STREQUAL ""
+     AND NOT
+         "${CMAKE_HOST_SYSTEM_PROCESSOR}"
+         STREQUAL
+         "")
+    set(_arch "${CMAKE_HOST_SYSTEM_PROCESSOR}")
+  else()
+    set(_arch "${CMAKE_SYSTEM_PROCESSOR}")
+  endif()
+
+  # make it lowercase for comparison
+  string(TOLOWER "${_arch}" _arch)
+
+  if(_arch STREQUAL x86 OR _arch MATCHES "^i[3456]86$")
+    set(${arch}
+        x86
+        PARENT_SCOPE)
+  elseif(
+    _arch STREQUAL x64
+    OR _arch STREQUAL x86_64
+    OR _arch STREQUAL amd64)
+    set(${arch}
+        x64
+        PARENT_SCOPE)
+  elseif(_arch STREQUAL arm)
+    set(${arch}
+        arm
+        PARENT_SCOPE)
+  elseif(_arch STREQUAL arm64 OR _arch STREQUAL aarch64)
+    set(${arch}
+        arm64
+        PARENT_SCOPE)
+  else()
+    # fallback to the most common architecture
+    message(STATUS "Unknown architecture ${_arch} - using x64")
+    set(${arch}
+        x64
+        PARENT_SCOPE)
+  endif()
+endfunction()
diff --git a/src/VCEnvironment.cmake b/src/VCEnvironment.cmake
index 86866f61..5714b4ee 100644
--- a/src/VCEnvironment.cmake
+++ b/src/VCEnvironment.cmake
@@ -1,29 +1,5 @@
 include("${ProjectOptions_SRC_DIR}/Utilities.cmake")
 
-macro(detect_architecture)
-  # detect the architecture
-  string(TOLOWER "${CMAKE_SYSTEM_PROCESSOR}" CMAKE_SYSTEM_PROCESSOR_LOWER)
-  if(CMAKE_SYSTEM_PROCESSOR_LOWER STREQUAL x86 OR CMAKE_SYSTEM_PROCESSOR_LOWER MATCHES "^i[3456]86$")
-    set(VCVARSALL_ARCH x86)
-  elseif(
-    CMAKE_SYSTEM_PROCESSOR_LOWER STREQUAL x64
-    OR CMAKE_SYSTEM_PROCESSOR_LOWER STREQUAL x86_64
-    OR CMAKE_SYSTEM_PROCESSOR_LOWER STREQUAL amd64)
-    set(VCVARSALL_ARCH x64)
-  elseif(CMAKE_SYSTEM_PROCESSOR_LOWER STREQUAL arm)
-    set(VCVARSALL_ARCH arm)
-  elseif(CMAKE_SYSTEM_PROCESSOR_LOWER STREQUAL arm64 OR CMAKE_SYSTEM_PROCESSOR_LOWER STREQUAL aarch64)
-    set(VCVARSALL_ARCH arm64)
-  else()
-    if(CMAKE_HOST_SYSTEM_PROCESSOR)
-      set(VCVARSALL_ARCH ${CMAKE_HOST_SYSTEM_PROCESSOR})
-    else()
-      set(VCVARSALL_ARCH x64)
-      message(STATUS "Unkown architecture CMAKE_SYSTEM_PROCESSOR: ${CMAKE_SYSTEM_PROCESSOR_LOWER} - using x64")
-    endif()
-  endif()
-endmacro()
-
 # Run vcvarsall.bat and set CMake environment variables
 function(run_vcvarsall)
   # if MSVC but VSCMD_VER is not set, which means vcvarsall has not run
@@ -43,7 +19,7 @@ function(run_vcvarsall)
 
     if(EXISTS ${VCVARSALL_FILE})
       # detect the architecture
-      detect_architecture()
+      detect_architecture(VCVARSALL_ARCH)
 
       # run vcvarsall and print the environment variables
       message(STATUS "Running `${VCVARSALL_FILE} ${VCVARSALL_ARCH}` to set up the MSVC environment")