1# Copyright 2019 The meson development team
2#
3# Licensed under the Apache License, Version 2.0 (the "License");
4# you may not use this file except in compliance with the License.
5# You may obtain a copy of the License at
6#
7#     http://www.apache.org/licenses/LICENSE-2.0
8#
9# Unless required by applicable law or agreed to in writing, software
10# distributed under the License is distributed on an "AS IS" BASIS,
11# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
12# See the License for the specific language governing permissions and
13# limitations under the License.
14
15"""Abstractions for the LLVM/Clang compiler family."""
16
17import os
18import shutil
19import typing as T
20
21from ... import mesonlib
22from ...linkers import AppleDynamicLinker
23from .gnu import GnuLikeCompiler
24
25if T.TYPE_CHECKING:
26    from ...environment import Environment
27    from ...dependencies import Dependency  # noqa: F401
28
29clang_color_args = {
30    'auto': ['-Xclang', '-fcolor-diagnostics'],
31    'always': ['-Xclang', '-fcolor-diagnostics'],
32    'never': ['-Xclang', '-fno-color-diagnostics'],
33}  # type: T.Dict[str, T.List[str]]
34
35clang_optimization_args = {
36    '0': [],
37    'g': ['-Og'],
38    '1': ['-O1'],
39    '2': ['-O2'],
40    '3': ['-O3'],
41    's': ['-Os'],
42}  # type: T.Dict[str, T.List[str]]
43
44class ClangCompiler(GnuLikeCompiler):
45    def __init__(self, defines: T.Optional[T.Dict[str, str]]):
46        super().__init__()
47        self.id = 'clang'
48        self.defines = defines or {}
49        self.base_options.append('b_colorout')
50        # TODO: this really should be part of the linker base_options, but
51        # linkers don't have base_options.
52        if isinstance(self.linker, AppleDynamicLinker):
53            self.base_options.append('b_bitcode')
54        # All Clang backends can also do LLVM IR
55        self.can_compile_suffixes.add('ll')
56
57    def get_colorout_args(self, colortype: str) -> T.List[str]:
58        return clang_color_args[colortype][:]
59
60    def has_builtin_define(self, define: str) -> bool:
61        return define in self.defines
62
63    def get_builtin_define(self, define: str) -> T.Optional[str]:
64        return self.defines.get(define)
65
66    def get_optimization_args(self, optimization_level: str) -> T.List[str]:
67        return clang_optimization_args[optimization_level]
68
69    def get_pch_suffix(self) -> str:
70        return 'pch'
71
72    def get_pch_use_args(self, pch_dir: str, header: str) -> T.List[str]:
73        # Workaround for Clang bug http://llvm.org/bugs/show_bug.cgi?id=15136
74        # This flag is internal to Clang (or at least not documented on the man page)
75        # so it might change semantics at any time.
76        return ['-include-pch', os.path.join(pch_dir, self.get_pch_name(header))]
77
78    def has_multi_arguments(self, args: T.List[str], env: 'Environment') -> T.List[str]:
79        myargs = ['-Werror=unknown-warning-option', '-Werror=unused-command-line-argument']
80        if mesonlib.version_compare(self.version, '>=3.6.0'):
81            myargs.append('-Werror=ignored-optimization-argument')
82        return super().has_multi_arguments(
83            myargs + args,
84            env)
85
86    def has_function(self, funcname: str, prefix: str, env: 'Environment', *,
87                     extra_args: T.Optional[T.List[str]] = None,
88                     dependencies: T.Optional[T.List['Dependency']] = None) -> bool:
89        if extra_args is None:
90            extra_args = []
91        # Starting with XCode 8, we need to pass this to force linker
92        # visibility to obey OS X/iOS/tvOS minimum version targets with
93        # -mmacosx-version-min, -miphoneos-version-min, -mtvos-version-min etc.
94        # https://github.com/Homebrew/homebrew-core/issues/3727
95        # TODO: this really should be communicated by the linker
96        if isinstance(self.linker, AppleDynamicLinker) and mesonlib.version_compare(self.version, '>=8.0'):
97            extra_args.append('-Wl,-no_weak_imports')
98        return super().has_function(funcname, prefix, env, extra_args=extra_args,
99                                    dependencies=dependencies)
100
101    def openmp_flags(self) -> T.List[str]:
102        if mesonlib.version_compare(self.version, '>=3.8.0'):
103            return ['-fopenmp']
104        elif mesonlib.version_compare(self.version, '>=3.7.0'):
105            return ['-fopenmp=libomp']
106        else:
107            # Shouldn't work, but it'll be checked explicitly in the OpenMP dependency.
108            return []
109
110    @classmethod
111    def use_linker_args(cls, linker: str) -> T.List[str]:
112        # Clang additionally can use a linker specified as a path, which GCC
113        # (and other gcc-like compilers) cannot. This is becuse clang (being
114        # llvm based) is retargetable, while GCC is not.
115        #
116        if shutil.which(linker):
117            if not shutil.which(linker):
118                raise mesonlib.MesonException(
119                    'Cannot find linker {}.'.format(linker))
120            return ['-fuse-ld={}'.format(linker)]
121        return super().use_linker_args(linker)
122
123    def get_has_func_attribute_extra_args(self, name):
124        # Clang only warns about unknown or ignored attributes, so force an
125        # error.
126        return ['-Werror=attributes']
127
128    def get_coverage_link_args(self) -> T.List[str]:
129        return ['--coverage']
130