1. Set CMAKE_FIND_ROOT_PATH unconditionally.
Revise the implementation from commit a7f41a7ee4 (Android: Fix find_*
search order within NDK for unified toolchains, 2020-10-13). In the old
implementation, if people set CMAKE_FIND_ROOT_PATH, CMAKE_ANDROID_NDK
won't be added to find root. And all paths added to CMAKE_SYSTEM_*_PATH
below will be rerooted to the user specified root.
2. Add api level specific library path to CMAKE_SYSTEM_PREFIX_PATH.
As the discussion in [1], some people want the paths added by
UnixPaths.cmake. They install their libraries according to
GNUInstallDirs [2].
As a result, we cannot clear CMAKE_SYSTEM_PREFIX_PATH. It includes /usr
so no matter what we specify in CMAKE_SYSTEM_LIBRARY_PATH,
/usr/lib/<arch> will be searched first.
The author also pointed out a way to solve this issue [3]. In addition
to other paths, CMake also searches <root>/<prefix> [4]. So we can add
the API specific lib path to the beginning of CMAKE_SYSTEM_PREFIX_PATH,
to have it searched first.
[1] https://android-review.googlesource.com/c/platform/ndk/+/1486800
[2] https://cmake.org/cmake/help/latest/module/GNUInstallDirs.html
[3] https://github.com/android/ndk/issues/1179#issuecomment-613435081
[4] 11425041f0/Source/cmSearchPath.cxx (L202)
The NDK build system now uses only a single toolchain in
<ndk>/toolchains/llvm/prebuilt/<host>
Its compilers are always `bin/{clang,clang++}` and its binutils are
always `bin/<triple>-*`. It is a standalone toolchain:
* The Anrdoid API level is specified at the end of `--target=`.
* The standard library may be specified via `-stdlib=`.
* No need to pass system includes or libraries explicitly.
* No need to pass `--sysroot` or `-gcc-toolchain`.
Teach CMake to recognize NDK versions that have a unified
toolchain with its own sysroot and use the above approach.
Fixes: #18739
NDK r18 drops GCC toolchains and some STL types. We need to choose a
clang toolchain by default when no gcc toolchains are available. Switch
the STL type default to `c++_static` when the old `gnustl_static`
default is not available.
Update the test suite to not run tests for STL types that do not exist.
Also do not expect the gcc toolchain `cpp` tool to be available because
r18 does not provide it. Also teach it to tolerate `gcc -dumpmachine`
output like `arm--linux-android` that differs from the toolchain prefix.
Fixes: #18301
Run the `clang-format.bash` script to update all our C and C++ code to a
new style defined by `.clang-format`. Use `clang-format` version 6.0.
* If you reached this commit for a line in `git blame`, re-run the blame
operation starting at the parent of this commit to see older history
for the content.
* See the parent commit for instructions to rebase a change across this
style transition commit.
The `armeabi` ABI is no longer available, so we can no longer use it by
default unconditionally. Instead detect all available ABIs and choose
the oldest arm ABI that is available.
Also update the test suite to account for the lack of `armeabi` support
and pass as of Android NDK r17-beta2.
The logic added in commit v3.6.0-rc1~30^2 (Add a variable to specify
language-wide system include directories, 2016-05-24) to use
`CMAKE_<LANG>_STANDARD_INCLUDE_DIRECTORIES` incorrectly filters them by
`CMAKE_<LANG>_IMPLICIT_INCLUDE_DIRECTORIES`. Rather than recognizing
this, commit v3.8.0-rc1~60^2 (Android: Pass sysroot include directory
explicitly, 2017-01-20) worked around the problem by incorrectly
removing `/usr/include` from `CMAKE_<LANG>_IMPLICIT_INCLUDE_DIRECTORIES`
so it worked in `CMAKE_<LANG>_STANDARD_INCLUDE_DIRECTORIES`.
By not filtering out `/usr/include` from user-specified include
directories, we allow the code
include_directories(${CMAKE_SYSROOT}/usr/include)
to place the include directory too early on the command line.
Fix support for standard include directories to not be filtered by
implicit include directories, and do not remove `/usr/include` from the
list of implicit include directories for Android builds. Add a test
case to verify that an explicit `/usr/include` is ignored in favor
of the standard directory at the end.
Fixes: #17059
Expose the binutils' machine name (typically used as a prefix on the
tool names) publicly. This is expected to match the `gcc -dumpmachine`
value.
Suggested-by: Ruslan Baratov <ruslan_baratov@yahoo.com>
The NDK provides prebuilt toolchain files in directories named for the
host architecture. The NDK build system calls this `HOST_TAG`.
Expose the value publicly for use by clients that need to pass it
to external tools.
Suggested-by: Ruslan Baratov <ruslan_baratov@yahoo.com>
When this variable is not set by the user or toolchain file, set it to
the default selected. This will be useful for client code that needs to
pass the value to an external tool that needs to find the same toolchain
in the NDK. Leave it empty for a standalone toolchain.
Suggested-by: Ruslan Baratov <ruslan_baratov@yahoo.com>
Add missing "unwind" and "atomic" libraries needed for this combination.
See `${ndk}/sources/cxx-stl/llvm-libc++/libs/armeabi/libc++.a` for the
libraries the NDK uses.
Issue: #16380
We use `-Werror` in the Android test builds to make sure there are
no warnings that we care about (e.g. unused flags). However, the
NDK r13 tools produce a warning about their own builtins:
```
<built-in>: In function 'float abs(float)':
<built-in>: warning: conflicts with previous declaration here [-Wattributes]
```
Suppress this warning so that we can continue using `-Werror` but
tolerate these warnings.
