Merge pull request #388 from google/better_android_toolchains

Improve Android CMake toolchains.

README.md

@@ -321,20 +321,29 @@ It's sometimes useful to build Draco command line tools and run them directly on
 Android devices via adb.
 
 ~~~~~ bash
+# all targets require CMAKE_ANDROID_NDK. It can be set in the environment or
+# within CMake. For example, this would set it in your environment.
+$ export CMAKE_ANDROID_NDK=path/to/ndk
+# To set it within CMake, add -DCMAKE_ANDROID_NDK=path/to/ndk to your CMake
+# command.
+
 # arm
-$ cmake path/to/draco -DCMAKE_TOOLCHAIN_FILE=path/to/draco/cmake/toolchains/armv7-android-clang-libstdc++.cmake
+$ cmake path/to/draco -DCMAKE_TOOLCHAIN_FILE=path/to/draco/cmake/toolchains/armv7-android-ndk-libcpp.cmake
 $ make
 
 # arm64
-$ cmake path/to/draco -DCMAKE_TOOLCHAIN_FILE=path/to/draco/cmake/toolchains/arm64-android-clang-libstdc++.cmake
+$ cmake path/to/draco -DCMAKE_TOOLCHAIN_FILE=path/to/draco/cmake/toolchains/arm64-android-ndk-libcpp.cmake
+$ make
+
+# x86
+$ cmake path/to/draco -DCMAKE_TOOLCHAIN_FILE=path/to/draco/cmake/toolchains/x86-android-ndk-libcpp.cmake
+$ make
+
+# x86_64
+$ cmake path/to/draco -DCMAKE_TOOLCHAIN_FILE=path/to/draco/cmake/toolchains/x86_64-android-ndk-libcpp.cmake
 $ make
 ~~~~~
 
-Note: The above assumes that make_standalone_toolchain.py has been used to
-generate a standalone NDK toolchain for arm or arm64. In addition, Draco, as of
-this writing, requires that libc++ is used for the stl argument when the
-toolchain is generated.
-
 After building the tools they can be moved to an android device via the use of
 `adb push`, and then run within an `adb shell` instance.
 

cmake/toolchains/arm64-android-clang-libstdc++.cmake

@@ -1,18 +0,0 @@
-if (NOT DRACO_CMAKE_TOOLCHAINS_ARM64_ANDROID_CLANG_LIBSTDCPP_CMAKE_)
-set(DRACO_CMAKE_TOOLCHAINS_ARM64_ANDROID_CLANG_LIBSTDCPP_CMAKE_ 1)
-
-set(CMAKE_SYSTEM_NAME "Linux")
-
-if ("${CROSS}" STREQUAL "")
-  # Default the cross compiler prefix to something known to work.
-  set(CROSS aarch64-linux-android-)
-endif ()
-
-set(CMAKE_POSITION_INDEPENDENT_CODE ON)
-set(CMAKE_C_COMPILER ${CROSS}clang)
-set(CMAKE_CXX_COMPILER ${CROSS}clang++)
-set(CMAKE_EXE_LINKER_FLAGS  "${CMAKE_EXE_LINKER_FLAGS} -pie -static-libstdc++")
-set(AS_EXECUTABLE ${CROSS}as)
-set(CMAKE_SYSTEM_PROCESSOR "arm64")
-
-endif ()  # DRACO_CMAKE_TOOLCHAINS_ARM64_ANDROID_CLANG_LIBSTDCPP_CMAKE_

cmake/toolchains/arm64-android-ndk-libcpp.cmake

@@ -0,0 +1,12 @@
+if (NOT DRACO_CMAKE_TOOLCHAINS_ARM64_ANDROID_NDK_LIBCPP_CMAKE_)
+set(DRACO_CMAKE_TOOLCHAINS_ARM64_ANDROID_NDK_LIBCPP_CMAKE_ 1)
+
+include("${CMAKE_CURRENT_LIST_DIR}/../util.cmake")
+
+set(CMAKE_SYSTEM_NAME Android)
+set(CMAKE_ANDROID_ARCH_ABI arm64-v8a)
+require_variable(CMAKE_ANDROID_NDK)
+set_variable_if_unset(CMAKE_SYSTEM_VERSION 21)
+set_variable_if_unset(CMAKE_ANDROID_STL_TYPE c++_static)
+
+endif ()  # DRACO_CMAKE_TOOLCHAINS_ARM64_ANDROID_NDK_LIBCPP_CMAKE_

cmake/toolchains/armv7-android-clang-libstdc++.cmake

@@ -1,18 +0,0 @@
-if (NOT DRACO_CMAKE_TOOLCHAINS_ARMV7_ANDROID_CLANG_LIBSTDCPP_CMAKE_)
-set(DRACO_CMAKE_TOOLCHAINS_ARMV7_ANDROID_CLANG_LIBSTDCPP_CMAKE_ 1)
-
-set(CMAKE_SYSTEM_NAME "Linux")
-
-if ("${CROSS}" STREQUAL "")
-  # Default the cross compiler prefix to something known to work.
-  set(CROSS arm-linux-androideabi-)
-endif ()
-
-set(CMAKE_POSITION_INDEPENDENT_CODE ON)
-set(CMAKE_C_COMPILER ${CROSS}clang)
-set(CMAKE_CXX_COMPILER ${CROSS}clang++)
-set(CMAKE_EXE_LINKER_FLAGS  "${CMAKE_EXE_LINKER_FLAGS} -pie -static-libstdc++")
-set(AS_EXECUTABLE ${CROSS}as)
-set(CMAKE_SYSTEM_PROCESSOR "armv7")
-
-endif ()  # DRACO_CMAKE_TOOLCHAINS_ARMV7_ANDROID_CLANG_LIBSTDCPP_CMAKE_

cmake/toolchains/armv7-android-ndk-libcpp.cmake

@@ -0,0 +1,12 @@
+if (NOT DRACO_CMAKE_TOOLCHAINS_ARMV7_ANDROID_NDK_LIBCPP_CMAKE_)
+set(DRACO_CMAKE_TOOLCHAINS_ARMV7_ANDROID_NDK_LIBCPP_CMAKE_ 1)
+
+include("${CMAKE_CURRENT_LIST_DIR}/../util.cmake")
+
+set(CMAKE_SYSTEM_NAME Android)
+set(CMAKE_ANDROID_ARCH_ABI armeabi-v7a)
+require_variable(CMAKE_ANDROID_NDK)
+set_variable_if_unset(CMAKE_SYSTEM_VERSION 18)
+set_variable_if_unset(CMAKE_ANDROID_STL_TYPE c++_static)
+
+endif ()  # DRACO_CMAKE_TOOLCHAINS_ARMV7_ANDROID_NDK_LIBCPP_CMAKE_

cmake/toolchains/x86-android-ndk-libcpp.cmake

@@ -0,0 +1,12 @@
+if (NOT DRACO_CMAKE_TOOLCHAINS_X86_ANDROID_NDK_LIBCPP_CMAKE_)
+set(DRACO_CMAKE_TOOLCHAINS_X86_ANDROID_NDK_LIBCPP_CMAKE_ 1)
+
+include("${CMAKE_CURRENT_LIST_DIR}/../util.cmake")
+
+set(CMAKE_SYSTEM_NAME Android)
+set(CMAKE_ANDROID_ARCH_ABI x86)
+require_variable(CMAKE_ANDROID_NDK)
+set_variable_if_unset(CMAKE_SYSTEM_VERSION 18)
+set_variable_if_unset(CMAKE_ANDROID_STL_TYPE c++_static)
+
+endif ()  # DRACO_CMAKE_TOOLCHAINS_X86_ANDROID_NDK_LIBCPP_CMAKE_

cmake/toolchains/x86_64-android-ndk-libcpp.cmake

@@ -0,0 +1,12 @@
+if (NOT DRACO_CMAKE_TOOLCHAINS_X86_64_ANDROID_NDK_LIBCPP_CMAKE_)
+set(DRACO_CMAKE_TOOLCHAINS_X86_64_ANDROID_NDK_LIBCPP_CMAKE_ 1)
+
+include("${CMAKE_CURRENT_LIST_DIR}/../util.cmake")
+
+set(CMAKE_SYSTEM_NAME Android)
+set(CMAKE_ANDROID_ARCH_ABI x86_64)
+require_variable(CMAKE_ANDROID_NDK)
+set_variable_if_unset(CMAKE_SYSTEM_VERSION 21)
+set_variable_if_unset(CMAKE_ANDROID_STL_TYPE c++_static)
+
+endif ()  # DRACO_CMAKE_TOOLCHAINS_X86_64_ANDROID_NDK_LIBCPP_CMAKE_

cmake/util.cmake

@@ -51,5 +51,26 @@ function (set_compiler_launcher launcher_flag launcher_name)
   endif ()
 endfunction ()
 
+# Terminates CMake execution when $var_name is unset in CMake and environment,
+# and then calls set_variable_if_unset() to ensure variable is set for caller.
+macro(require_variable var_name)
+  if ((NOT DEFINED ${var_name}) AND ("$ENV{${var_name}}" STREQUAL ""))
+    message(FATAL_ERROR "${var_name} must be set in cmake or environment.")
+  endif ()
+  set_variable_if_unset(${var_name} "")
+endmacro ()
+
+# Sets $var_name to $default_value if not already set in CMake or the
+# environment.
+macro (set_variable_if_unset var_name default_value)
+  if (DEFINED ${var_name})
+    return ()
+  elseif (NOT "$ENV{${var_name}}" STREQUAL "")
+    set(${var_name} $ENV{${var_name}})
+  else ()
+    set(${var_name} ${default_value})
+  endif ()
+endmacro ()
+
 endif()  # DRACO_CMAKE_UTIL_CMAKE_