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
In commit c4b4d8b3a6 (POSITION_INDEPENDENT_CODE: Manage link flags for
executables, 2018-10-02, v3.14.0-rc1~395^2) we accidentally removed our
Android-specific logic for PIE under the CMP0083 OLD behavior. Restore
it and also implement Android-specific logic for CMP0083 NEW behavior.
Fixes: #19393
The unified headers are preferred as of NDK r15, so use them by default
if available and provide an option to use the deprecated headers.
Inspired-by: Florent Castelli <florent.castelli@gmail.com>
Fixes: #16584
Add `-fPIE -pie` to the default executable link flags when
`CMAKE_POSITION_INDEPENDENT_CODE` is enabled. This is required by
Android 16 and above for executables to run on the device.
Closes: #16382
If the toolchain file or cache does not set this, enable it
automatically based on the Android API version. Versions 16
and above expect position independent code.
Use the main `CMAKE_POSITION_INDEPENDENT_CODE` setting in favor of
hard-coding `-fpic` or `-fPIC` in the compiler flags for each ABI.
This allows CMake to use `-fpie` or `-fPIE` as needed when sources
are meant for executables, and `-fpic` or `-fPIC` for other sources.
See `${ndk}/build/core/default-build-commands.mk` for link flags the NDK
uses for executables. Add them to our default executable link flags.
Suppress `nocopyreloc` on `arm64-v8a` because it does not work with
some STL types.
Closes: #16380
The Android NDK source repository at
https://android.googlesource.com/platform/ndk.git
has `<ndk>/build/core/toolchains/*/setup.mk` files that store tables of
information for their build system. Add an equivalent file for each
compiler/abi combination.
