From 02dfb0233b2a99d195c29163f96fd19204b3bd70 Mon Sep 17 00:00:00 2001
From: Dan Albert <danalbert@google.com>
Date: Thu, 16 Sep 2021 15:24:48 -0700
Subject: [PATCH] Improve the cmake compiler ID workaround.

Move this into the hook so it works for non-toolchain file users too.
Thanks hhb for the pointer!

Test: re-tested this on Windows
Bug: https://github.com/android/ndk/issues/1581
Change-Id: I39a1c8646d5853eea4bf557c6f6efa2ca5244cf2
---
 build/cmake/android.toolchain.cmake           | 19 ---------------
 .../cmake/hooks/pre/Determine-Compiler.cmake  | 23 +++++++++++++++++++
 docs/changelogs/Changelog-r23.md              |  3 +--
 3 files changed, 24 insertions(+), 21 deletions(-)

diff --git a/build/cmake/android.toolchain.cmake b/build/cmake/android.toolchain.cmake
index 18d577f2..f1bc702c 100644
--- a/build/cmake/android.toolchain.cmake
+++ b/build/cmake/android.toolchain.cmake
@@ -268,25 +268,6 @@ endif()
 set(ANDROID_TOOLCHAIN_ROOT
   "${CMAKE_ANDROID_NDK}/toolchains/llvm/prebuilt/${ANDROID_HOST_TAG}")
 
-# If we don't explicitly set the target CMake will ID the compiler using the
-# default target, causing MINGW to be defined when a Windows host is used.
-# https://github.com/android/ndk/issues/1581
-# https://gitlab.kitware.com/cmake/cmake/-/issues/22647
-if(CMAKE_ANDROID_ARCH_ABI STREQUAL armeabi-v7a)
-  set(ANDROID_LLVM_TRIPLE armv7-none-linux-androideabi)
-elseif(CMAKE_ANDROID_ARCH_ABI STREQUAL arm64-v8a)
-  set(ANDROID_LLVM_TRIPLE aarch64-none-linux-android)
-elseif(CMAKE_ANDROID_ARCH_ABI STREQUAL x86)
-  set(ANDROID_LLVM_TRIPLE i686-none-linux-android)
-elseif(CMAKE_ANDROID_ARCH_ABI STREQUAL x86_64)
-  set(ANDROID_LLVM_TRIPLE x86_64-none-linux-android)
-else()
-  message(FATAL_ERROR "Invalid Android ABI: ${ANDROID_ABI}.")
-endif()
-set(CMAKE_ASM_COMPILER_TARGET "${ANDROID_LLVM_TRIPLE}${CMAKE_SYSTEM_VERSION}")
-set(CMAKE_C_COMPILER_TARGET "${ANDROID_LLVM_TRIPLE}${CMAKE_SYSTEM_VERSION}")
-set(CMAKE_CXX_COMPILER_TARGET "${ANDROID_LLVM_TRIPLE}${CMAKE_SYSTEM_VERSION}")
-
 # NB: This variable causes CMake to automatically pass --sysroot to the
 # toolchain. Studio currently relies on this to recognize Android builds. If
 # this variable is removed, ensure that flag is still passed.
diff --git a/build/cmake/hooks/pre/Determine-Compiler.cmake b/build/cmake/hooks/pre/Determine-Compiler.cmake
index b8ed1bfe..ef0228f1 100644
--- a/build/cmake/hooks/pre/Determine-Compiler.cmake
+++ b/build/cmake/hooks/pre/Determine-Compiler.cmake
@@ -15,3 +15,26 @@
 # This is a hook file that will be included by cmake at the beginning of
 # Modules/Platform/Android/Determine-Compiler.cmake.
 
+# Skip hook for the legacy toolchain workflow.
+if(CMAKE_SYSTEM_VERSION EQUAL 1)
+  return()
+endif()
+
+# If we don't explicitly set the target CMake will ID the compiler using the
+# default target, causing MINGW to be defined when a Windows host is used.
+# https://github.com/android/ndk/issues/1581
+# https://gitlab.kitware.com/cmake/cmake/-/issues/22647
+if(CMAKE_ANDROID_ARCH_ABI STREQUAL armeabi-v7a)
+  set(ANDROID_LLVM_TRIPLE armv7-none-linux-androideabi)
+elseif(CMAKE_ANDROID_ARCH_ABI STREQUAL arm64-v8a)
+  set(ANDROID_LLVM_TRIPLE aarch64-none-linux-android)
+elseif(CMAKE_ANDROID_ARCH_ABI STREQUAL x86)
+  set(ANDROID_LLVM_TRIPLE i686-none-linux-android)
+elseif(CMAKE_ANDROID_ARCH_ABI STREQUAL x86_64)
+  set(ANDROID_LLVM_TRIPLE x86_64-none-linux-android)
+else()
+  message(FATAL_ERROR "Invalid Android ABI: ${ANDROID_ABI}.")
+endif()
+set(CMAKE_ASM_COMPILER_TARGET "${ANDROID_LLVM_TRIPLE}${CMAKE_SYSTEM_VERSION}")
+set(CMAKE_C_COMPILER_TARGET "${ANDROID_LLVM_TRIPLE}${CMAKE_SYSTEM_VERSION}")
+set(CMAKE_CXX_COMPILER_TARGET "${ANDROID_LLVM_TRIPLE}${CMAKE_SYSTEM_VERSION}")
diff --git a/docs/changelogs/Changelog-r23.md b/docs/changelogs/Changelog-r23.md
index de411231..c7e37acd 100644
--- a/docs/changelogs/Changelog-r23.md
+++ b/docs/changelogs/Changelog-r23.md
@@ -55,8 +55,7 @@ For Android Studio issues, follow the docs on the [Android Studio site].
   `MINGW` to be incorrectly defined by CMake when building for Android on a
   Windows host. This only affected those using the Android toolchain file when
   CMake 3.21 or newer was used. This likely was not a regression for users not
-  using the Android toolchain, and the workaround only affects toolchain file
-  users.
+  using the Android toolchain. The change will fix both use cases.
 
 [CMake Issue 22647]: https://gitlab.kitware.com/cmake/cmake/-/issues/22647
 [Issue 1536]: https://github.com/android/ndk/issues/1536