1 files changed, 258 insertions, 0 deletions
diff --git a/mesonbuild/cmake/toolchain.py b/mesonbuild/cmake/toolchain.py
new file mode 100644
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--- /dev/null
+++ b/mesonbuild/cmake/toolchain.py
@@ -0,0 +1,258 @@
+# Copyright 2020 The Meson development team
+
+# Licensed under the Apache License, Version 2.0 (the "License");
+# you may not use this file except in compliance with the License.
+# You may obtain a copy of the License at
+
+#     http://www.apache.org/licenses/LICENSE-2.0
+
+# Unless required by applicable law or agreed to in writing, software
+# distributed under the License is distributed on an "AS IS" BASIS,
+# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+# See the License for the specific language governing permissions and
+# limitations under the License.
+from __future__ import annotations
+
+from pathlib import Path
+from .traceparser import CMakeTraceParser
+from ..envconfig import CMakeSkipCompilerTest
+from .common import language_map, cmake_get_generator_args
+from .. import mlog
+
+import shutil
+import typing as T
+from enum import Enum
+from textwrap import dedent
+
+if T.TYPE_CHECKING:
+    from .executor import CMakeExecutor
+    from ..environment import Environment
+    from ..compilers import Compiler
+    from ..mesonlib import MachineChoice
+
+class CMakeExecScope(Enum):
+    SUBPROJECT = 'subproject'
+    DEPENDENCY = 'dependency'
+
+class CMakeToolchain:
+    def __init__(self, cmakebin: 'CMakeExecutor', env: 'Environment', for_machine: MachineChoice, exec_scope: CMakeExecScope, build_dir: Path, preload_file: T.Optional[Path] = None) -> None:
+        self.env = env
+        self.cmakebin = cmakebin
+        self.for_machine = for_machine
+        self.exec_scope = exec_scope
+        self.preload_file = preload_file
+        self.build_dir = build_dir
+        self.build_dir = self.build_dir.resolve()
+        self.toolchain_file = build_dir / 'CMakeMesonToolchainFile.cmake'
+        self.cmcache_file = build_dir / 'CMakeCache.txt'
+        self.minfo = self.env.machines[self.for_machine]
+        self.properties = self.env.properties[self.for_machine]
+        self.compilers = self.env.coredata.compilers[self.for_machine]
+        self.cmakevars = self.env.cmakevars[self.for_machine]
+        self.cmakestate = self.env.coredata.cmake_cache[self.for_machine]
+
+        self.variables = self.get_defaults()
+        self.variables.update(self.cmakevars.get_variables())
+
+        # Determine whether CMake the compiler test should be skipped
+        skip_status = self.properties.get_cmake_skip_compiler_test()
+        self.skip_check = skip_status == CMakeSkipCompilerTest.ALWAYS
+        if skip_status == CMakeSkipCompilerTest.DEP_ONLY and self.exec_scope == CMakeExecScope.DEPENDENCY:
+            self.skip_check = True
+        if not self.properties.get_cmake_defaults():
+            self.skip_check = False
+
+        assert self.toolchain_file.is_absolute()
+
+    def write(self) -> Path:
+        if not self.toolchain_file.parent.exists():
+            self.toolchain_file.parent.mkdir(parents=True)
+        self.toolchain_file.write_text(self.generate(), encoding='utf-8')
+        self.cmcache_file.write_text(self.generate_cache(), encoding='utf-8')
+        mlog.cmd_ci_include(self.toolchain_file.as_posix())
+        return self.toolchain_file
+
+    def get_cmake_args(self) -> T.List[str]:
+        args = ['-DCMAKE_TOOLCHAIN_FILE=' + self.toolchain_file.as_posix()]
+        if self.preload_file is not None:
+            args += ['-DMESON_PRELOAD_FILE=' + self.preload_file.as_posix()]
+        return args
+
+    @staticmethod
+    def _print_vars(vars: T.Dict[str, T.List[str]]) -> str:
+        res = ''
+        for key, value in vars.items():
+            res += 'set(' + key
+            for i in value:
+                res += f' "{i}"'
+            res += ')\n'
+        return res
+
+    def generate(self) -> str:
+        res = dedent('''\
+            ######################################
+            ###  AUTOMATICALLY GENERATED FILE  ###
+            ######################################
+
+            # This file was generated from the configuration in the
+            # relevant meson machine file. See the meson documentation
+            # https://mesonbuild.com/Machine-files.html for more information
+
+            if(DEFINED MESON_PRELOAD_FILE)
+                include("${MESON_PRELOAD_FILE}")
+            endif()
+
+        ''')
+
+        # Escape all \ in the values
+        for key, value in self.variables.items():
+            self.variables[key] = [x.replace('\\', '/') for x in value]
+
+        # Set compiler
+        if self.skip_check:
+            self.update_cmake_compiler_state()
+            res += '# CMake compiler state variables\n'
+            for lang, vars in self.cmakestate:
+                res += f'# -- Variables for language {lang}\n'
+                res += self._print_vars(vars)
+                res += '\n'
+            res += '\n'
+
+        # Set variables from the current machine config
+        res += '# Variables from meson\n'
+        res += self._print_vars(self.variables)
+        res += '\n'
+
+        # Add the user provided toolchain file
+        user_file = self.properties.get_cmake_toolchain_file()
+        if user_file is not None:
+            res += dedent('''
+                # Load the CMake toolchain file specified by the user
+                include("{}")
+
+            '''.format(user_file.as_posix()))
+
+        return res
+
+    def generate_cache(self) -> str:
+        if not self.skip_check:
+            return ''
+
+        res = ''
+        for name, v in self.cmakestate.cmake_cache.items():
+            res += f'{name}:{v.type}={";".join(v.value)}\n'
+        return res
+
+    def get_defaults(self) -> T.Dict[str, T.List[str]]:
+        defaults = {}  # type: T.Dict[str, T.List[str]]
+
+        # Do nothing if the user does not want automatic defaults
+        if not self.properties.get_cmake_defaults():
+            return defaults
+
+        # Best effort to map the meson system name to CMAKE_SYSTEM_NAME, which
+        # is not trivial since CMake lacks a list of all supported
+        # CMAKE_SYSTEM_NAME values.
+        SYSTEM_MAP = {
+            'android': 'Android',
+            'linux': 'Linux',
+            'windows': 'Windows',
+            'freebsd': 'FreeBSD',
+            'darwin': 'Darwin',
+        }  # type: T.Dict[str, str]
+
+        # Only set these in a cross build. Otherwise CMake will trip up in native
+        # builds and thing they are cross (which causes TRY_RUN() to break)
+        if self.env.is_cross_build(when_building_for=self.for_machine):
+            defaults['CMAKE_SYSTEM_NAME'] = [SYSTEM_MAP.get(self.minfo.system, self.minfo.system)]
+            defaults['CMAKE_SYSTEM_PROCESSOR'] = [self.minfo.cpu_family]
+
+        defaults['CMAKE_SIZEOF_VOID_P'] = ['8' if self.minfo.is_64_bit else '4']
+
+        sys_root = self.properties.get_sys_root()
+        if sys_root:
+            defaults['CMAKE_SYSROOT'] = [sys_root]
+
+        def make_abs(exe: str) -> str:
+            if Path(exe).is_absolute():
+                return exe
+
+            p = shutil.which(exe)
+            if p is None:
+                return exe
+            return p
+
+        # Set the compiler variables
+        for lang, comp_obj in self.compilers.items():
+            prefix = 'CMAKE_{}_'.format(language_map.get(lang, lang.upper()))
+
+            exe_list = comp_obj.get_exelist()
+            if not exe_list:
+                continue
+
+            if len(exe_list) >= 2 and not self.is_cmdline_option(comp_obj, exe_list[1]):
+                defaults[prefix + 'COMPILER_LAUNCHER'] = [make_abs(exe_list[0])]
+                exe_list = exe_list[1:]
+
+            exe_list[0] = make_abs(exe_list[0])
+            defaults[prefix + 'COMPILER'] = exe_list
+            if comp_obj.get_id() == 'clang-cl':
+                defaults['CMAKE_LINKER'] = comp_obj.get_linker_exelist()
+
+        return defaults
+
+    @staticmethod
+    def is_cmdline_option(compiler: 'Compiler', arg: str) -> bool:
+        if compiler.get_argument_syntax() == 'msvc':
+            return arg.startswith('/')
+        else:
+            return arg.startswith('-')
+
+    def update_cmake_compiler_state(self) -> None:
+        # Check if all variables are already cached
+        if self.cmakestate.languages.issuperset(self.compilers.keys()):
+            return
+
+        # Generate the CMakeLists.txt
+        mlog.debug('CMake Toolchain: Calling CMake once to generate the compiler state')
+        languages = list(self.compilers.keys())
+        lang_ids = [language_map.get(x, x.upper()) for x in languages]
+        cmake_content = dedent(f'''
+            cmake_minimum_required(VERSION 3.7)
+            project(CompInfo {' '.join(lang_ids)})
+        ''')
+
+        build_dir = Path(self.env.scratch_dir) / '__CMake_compiler_info__'
+        build_dir.mkdir(parents=True, exist_ok=True)
+        cmake_file = build_dir / 'CMakeLists.txt'
+        cmake_file.write_text(cmake_content, encoding='utf-8')
+
+        # Generate the temporary toolchain file
+        temp_toolchain_file = build_dir / 'CMakeMesonTempToolchainFile.cmake'
+        temp_toolchain_file.write_text(CMakeToolchain._print_vars(self.variables), encoding='utf-8')
+
+        # Configure
+        trace = CMakeTraceParser(self.cmakebin.version(), build_dir, self.env)
+        self.cmakebin.set_exec_mode(print_cmout=False, always_capture_stderr=trace.requires_stderr())
+        cmake_args = []
+        cmake_args += trace.trace_args()
+        cmake_args += cmake_get_generator_args(self.env)
+        cmake_args += [f'-DCMAKE_TOOLCHAIN_FILE={temp_toolchain_file.as_posix()}', '.']
+        rc, _, raw_trace = self.cmakebin.call(cmake_args, build_dir=build_dir, disable_cache=True)
+
+        if rc != 0:
+            mlog.warning('CMake Toolchain: Failed to determine CMake compilers state')
+            return
+
+        # Parse output
+        trace.parse(raw_trace)
+        self.cmakestate.cmake_cache = {**trace.cache}
+
+        vars_by_file = {k.name: v for (k, v) in trace.vars_by_file.items()}
+
+        for lang in languages:
+            lang_cmake = language_map.get(lang, lang.upper())
+            file_name = f'CMake{lang_cmake}Compiler.cmake'
+            vars = vars_by_file.setdefault(file_name, {})
+            vars[f'CMAKE_{lang_cmake}_COMPILER_FORCED'] = ['1']
+            self.cmakestate.update(lang, vars)