project.platform: add platform 'auto'

There were two problems:

  * On Windows, VS 2019 defaults to x64 while VS 2017 defaults to x86.
  * Too much focus on x86(-64) might mean that building stuff on ARM can
    become difficult.

These were all addressed by adding a new platform 'auto'.  On Windows,
it defaults to picking either x64 or x86 (depending on the host arch)
for both Boost and CMake.  On Linux, it lets the compiler decide what
arch to target.

2 files changed, 16 insertions, 37 deletions

diff --git a/project/cmake/build.py b/project/cmake/build.py
index 1e9a90d..a2fea78 100644
--- a/project/cmake/build.py
+++ b/project/cmake/build.py
@@ -34,7 +34,7 @@ from project.toolchain import ToolchainType
 from project.utils import normalize_path, mkdir_parent, run, setup_logging
 
 
-DEFAULT_PLATFORM = None
+DEFAULT_PLATFORM = Platform.AUTO
 DEFAULT_CONFIGURATION = Configuration.DEBUG
 DEFAULT_TOOLSET = ToolchainType.AUTO
 
@@ -81,18 +81,14 @@ class GenerationPhase:
     def _get_boost_args(self):
         if self.boost_dir is None:
             return []
-        stagedir = self._stagedir(self.boost_dir, self.platform, self.configuration)
+        root = self.boost_dir
+        librarydir = self.platform.boost_librarydir(self.configuration)
+        librarydir = os.path.join(self.boost_dir, librarydir)
         return [
-            '-D', f'BOOST_ROOT={self.boost_dir}',
-            '-D', f'BOOST_LIBRARYDIR={stagedir}',
+            '-D', f'BOOST_ROOT={root}',
+            '-D', f'BOOST_LIBRARYDIR={librarydir}',
         ]
 
-    @staticmethod
-    def _stagedir(boost_dir, platform, configuration):
-        if platform is None:
-            platform = Platform.native()
-        return os.path.join(boost_dir, 'stage', str(platform), str(configuration), 'lib')
-
     def run(self, toolchain):
         run_cmake(self._cmake_args(toolchain))
 
diff --git a/project/cmake/toolchain.py b/project/cmake/toolchain.py
index 14197aa..0e68738 100644
--- a/project/cmake/toolchain.py
+++ b/project/cmake/toolchain.py
@@ -11,7 +11,6 @@ import shutil
 
 import project.mingw
 from project.os import on_windows
-from project.platform import Platform
 from project.toolchain import ToolchainType
 
 
@@ -68,11 +67,9 @@ class MSVC(Auto):
         self.platform = platform
 
     def get_cmake_args(self):
-        if self.platform is None:
-            return []
         # This doesn't actually specify the generator of course, but I don't
         # want to implement VS detection logic.
-        return ['-A', self.platform.get_cmake_arch()]
+        return self.platform.cmake_msvc_args()
 
     def get_build_args(self):
         return ['/m']
@@ -102,17 +99,6 @@ class Makefile(Toolchain):
             file.write(contents)
         return cls(path)
 
-    @staticmethod
-    def _format_platform_compiler_flags(platform):
-        if platform is None:
-            # If the platform wasn't specified, don't use the -m flag, etc.
-            return ''
-        # Otherwise, use the standard -m32/-m64 flags.
-        return f'''
-set(CMAKE_C_FLAGS   -m{platform.get_address_model()})
-set(CMAKE_CXX_FLAGS -m{platform.get_address_model()})
-'''
-
     def get_cmake_args(self):
         return [
             '-D', f'CMAKE_TOOLCHAIN_FILE={self.path}',
@@ -131,7 +117,7 @@ class GCC(Makefile):
         return f'''
 set(CMAKE_C_COMPILER   gcc)
 set(CMAKE_CXX_COMPILER g++)
-{Makefile._format_platform_compiler_flags(platform)}'''
+{platform.makefile_toolchain_file()}'''
 
     @staticmethod
     def setup(platform, build_dir):
@@ -141,16 +127,13 @@ set(CMAKE_CXX_COMPILER g++)
 class MinGW(Makefile):
     @staticmethod
     def _format(platform):
-        if platform is None:
-            # MinGW only supports x86/x64, plus we need the platform for the
-            # compiler file name, so default to x64 unless specified.
-            platform = Platform.X64
+        paths = project.mingw.MinGW(platform)
         return f'''
-set(CMAKE_C_COMPILER   {project.mingw.get_gcc(platform)})
-set(CMAKE_CXX_COMPILER {project.mingw.get_gxx(platform)})
-set(CMAKE_AR           {project.mingw.get_ar(platform)})
-set(CMAKE_RANLIB       {project.mingw.get_ranlib(platform)})
-set(CMAKE_RC_COMPILER  {project.mingw.get_windres(platform)})
+set(CMAKE_C_COMPILER   {paths.gcc()})
+set(CMAKE_CXX_COMPILER {paths.gxx()})
+set(CMAKE_AR           {paths.ar()})
+set(CMAKE_RANLIB       {paths.ranlib()})
+set(CMAKE_RC_COMPILER  {paths.windres()})
 set(CMAKE_SYSTEM_NAME  Windows)
 '''
 
@@ -170,7 +153,7 @@ else()
     set(CMAKE_C_COMPILER   clang)
     set(CMAKE_CXX_COMPILER clang++)
 endif()
-{Makefile._format_platform_compiler_flags(platform)}'''
+{platform.makefile_toolchain_file()}'''
 
     def _get_makefile_generator(self):
         if on_windows():
@@ -192,7 +175,7 @@ class ClangCL(Clang):
 set(CMAKE_C_COMPILER   clang-cl)
 set(CMAKE_CXX_COMPILER clang-cl)
 set(CMAKE_SYSTEM_NAME  Windows)
-{Makefile._format_platform_compiler_flags(platform)}'''
+{platform.makefile_toolchain_file()}'''
 
     @staticmethod
     def setup(platform, build_dir):