1# Copyright (C) 2021 The Android Open Source Project
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# Helpers for stl property resolution.
16# These mappings taken from build/soong/cc/stl.go
17
18load("//build/bazel/platforms/arch/variants:constants.bzl", "arch_variant_to_constraints")
19
20_libcpp_stl_names = {
21    "libc++": True,
22    "libc++_static": True,
23    "": True,
24    "system": True,
25}
26
27# https://cs.android.com/android/platform/superproject/+/master:build/soong/cc/stl.go;l=162;drc=cb0ac95bde896fa2aa59193a37ceb580758c322c
28# this should vary based on vndk version
29# skip libm and libc because then we would have duplicates due to system_shared_library
30_libunwind = "//prebuilts/clang/host/linux-x86:libunwind"
31
32_ndk_system = "//prebuilts/ndk:ndk_system"
33
34_static_binary_deps = select({
35    arch_variant_to_constraints["android"]: [_libunwind],
36    arch_variant_to_constraints["linux_bionic"]: [_libunwind],
37    "//build/bazel/rules/apex:unbundled_app": [],
38    "//conditions:default": [],
39})
40
41def _stl_name_resolver(stl_name, is_shared):
42    if stl_name == "none":
43        return stl_name
44
45    if stl_name not in _libcpp_stl_names:
46        fail("Unhandled stl %s" % stl_name)
47
48    if stl_name in ("", "system"):
49        if is_shared:
50            stl_name = "libc++"
51        else:
52            stl_name = "libc++_static"
53    return stl_name
54
55def stl_info_from_attr(stl_name, is_shared, is_binary = False):
56    deps = _stl_deps(stl_name, is_shared, is_binary)
57    flags = _stl_flags(stl_name, is_shared)
58    return struct(
59        static_deps = deps.static,
60        shared_deps = deps.shared,
61        deps = deps.deps,
62        cppflags = flags.cppflags,
63        linkopts = flags.linkopts,
64    )
65
66def _stl_deps(stl_name, is_shared, is_binary = False):
67    if stl_name == "none":
68        return struct(static = [], shared = [], deps = [])
69
70    shared, static, deps = [], [], []
71    if stl_name in ("", "system"):
72        if is_shared:
73            shared = select({
74                # non-sdk variant, effective STL is libc++
75                arch_variant_to_constraints["android"]: [
76                    "//external/libcxx:libc++",
77                ],
78                # sdk variant, effective STL is ndk_system
79                "//build/bazel/rules/apex:unbundled_app": [
80                    "//bionic/libc:libstdc++",
81                ],
82                "//conditions:default": ["//external/libcxx:libc++"],  # libc++ is used by host variants
83            })
84            static = select({
85                arch_variant_to_constraints["android"]: [
86                    "//external/libcxxabi:libc++demangle",
87                ],
88                # sdk variant does not have an entry since ndk_system's deps have been added in `shared`
89                "//build/bazel/rules/apex:unbundled_app": [],
90                "//conditions:default": [],
91            })
92            deps = select({
93                # sdk variant, effective STL is ndk_system
94                "//build/bazel/rules/apex:unbundled_app": [
95                    _ndk_system,
96                ],
97                "//conditions:default": [],
98            })
99
100        else:
101            shared = select({
102                # sdk variant, effective STL is ndk_system
103                "//build/bazel/rules/apex:unbundled_app": [
104                    "//bionic/libc:libstdc++",
105                ],
106                "//conditions:default": [],
107            })
108            static = select({
109                # non-sdk variant, effective STL is libc++_static
110                arch_variant_to_constraints["android"]: [
111                    "//external/libcxx:libc++_static",
112                    "//external/libcxxabi:libc++demangle",
113                ],
114                # sdk variant does not have an entry since ndk_system's deps have been added in `shared`
115                "//build/bazel/rules/apex:unbundled_app": [],
116                "//conditions:default": ["//external/libcxx:libc++_static"],  # libc++_static is used by host variants
117            })
118            deps = select({
119                # sdk variant, effective STL is ndk_system
120                "//build/bazel/rules/apex:unbundled_app": [
121                    _ndk_system,
122                ],
123                "//conditions:default": [],
124            })
125    elif stl_name == "libc++":
126        shared = select({
127            arch_variant_to_constraints["android"]: [
128                "//external/libcxx:libc++",
129            ],
130            # sdk variant, effective STL is ndk_libc++_shared
131            "//build/bazel/rules/apex:unbundled_app": [
132                "//prebuilts/ndk:ndk_libc++_shared",
133            ],
134            "//conditions:default": ["//external/libcxx:libc++"],  # libc++ is used by host variants
135        })
136        static = select({
137            arch_variant_to_constraints["android"]: [
138                "//external/libcxxabi:libc++demangle",
139            ],
140            "//build/bazel/rules/apex:unbundled_app": [
141                "//prebuilts/ndk:ndk_libunwind",
142            ],
143            "//conditions:default": [],
144        })
145
146    elif stl_name == "libc++_static":
147        static = select({
148            arch_variant_to_constraints["android"]: [
149                "//external/libcxx:libc++_static",
150                "//external/libcxxabi:libc++demangle",
151            ],
152            # sdk variant, effective STL is ndk_libc++_static
153            "//build/bazel/rules/apex:unbundled_app": [
154                "//prebuilts/ndk:ndk_libc++_static",
155                "//prebuilts/ndk:ndk_libc++abi",
156                "//prebuilts/ndk:ndk_libunwind",
157            ],
158            "//conditions:default": ["//external/libcxx:libc++_static"],  # libc++_static is used by host variants
159        })
160    if is_binary:
161        static += _static_binary_deps
162    return struct(
163        static = static,
164        shared = shared,
165        deps = deps,
166    )
167
168def _stl_flags(stl_name, is_shared):
169    """returns flags that control STL inclusion
170
171    Should be kept up to date with
172    https://cs.android.com/android/platform/superproject/+/master:build/soong/cc/stl.go;l=197;drc=8722ca5486fa62c07520e09db54b1b330b48da17
173
174    Args:
175        stl_name: string, name of STL library to use
176        is_shared: bool, if true, the STL should be linked dynamically
177    Returns:
178        struct containing flags for CC compilation
179    """
180    stl_name = _stl_name_resolver(stl_name, is_shared)
181
182    cppflags_darwin = []
183    cppflags_windows_not_bionic = []
184    cppflags_not_bionic = []
185    linkopts_not_bionic = []
186    if stl_name in ("libc++", "libc++_static"):
187        cppflags_not_bionic.append("-nostdinc++")
188        linkopts_not_bionic.append("-nostdlib++")
189
190        # libc++'s headers are annotated with availability macros that
191        # indicate which version of Mac OS was the first to ship with a
192        # libc++ feature available in its *system's* libc++.dylib. We do
193        # not use the system's library, but rather ship our own. As such,
194        # these availability attributes are meaningless for us but cause
195        # build breaks when we try to use code that would not be available
196        # in the system's dylib.
197        cppflags_darwin.append("-D_LIBCPP_DISABLE_AVAILABILITY")
198
199        # Disable visiblity annotations since we're using static libc++.
200        cppflags_windows_not_bionic.append("-D_LIBCPP_DISABLE_VISIBILITY_ANNOTATIONS")
201        cppflags_windows_not_bionic.append("-D_LIBCXXABI_DISABLE_VISIBILITY_ANNOTATIONS")
202
203        # Use Win32 threads in libc++.
204        cppflags_windows_not_bionic.append("-D_LIBCPP_HAS_THREAD_API_WIN32")
205    elif stl_name in ("none"):
206        cppflags_not_bionic.append("-nostdinc++")
207        linkopts_not_bionic.append("-nostdlib++")
208    else:
209        #TODO(b/201079053) handle ndk STL flags
210        pass
211
212    return struct(
213        cppflags = select({
214            "//build/bazel_common_rules/platforms/os:bionic": [],
215            "//build/bazel/rules/apex:unbundled_app": [],
216            "//conditions:default": cppflags_not_bionic,
217        }) + select({
218            "//build/bazel_common_rules/platforms/os:darwin": cppflags_darwin,
219            "//build/bazel_common_rules/platforms/os:windows": (
220                cppflags_windows_not_bionic
221            ),
222            "//conditions:default": [],
223        }),
224        linkopts = select({
225            "//build/bazel_common_rules/platforms/os:bionic": [],
226            "//build/bazel/rules/apex:unbundled_app": [],
227            "//build/bazel/rules/apex:unbundled_app.arm": ["-Wl,--exclude-libs,libunwind.a"],
228            "//conditions:default": linkopts_not_bionic,
229        }),
230    )
231