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 `${ndk}/build/core/default-build-commands.mk` for link flags the NDK
uses for executables. Add them to our default executable link flags.
Suppress `nocopyreloc` on `arm64-v8a` because it does not work with
some STL types.
Closes: #16380
Add missing "unwind" and "atomic" libraries needed for this combination.
See `${ndk}/sources/cxx-stl/llvm-libc++/libs/armeabi/libc++.a` for the
libraries the NDK uses.
Issue: #16380
Per-source copyright/license notice headers that spell out copyright holder
names and years are hard to maintain and often out-of-date or plain wrong.
Precise contributor information is already maintained automatically by the
version control tool. Ultimately it is the receiver of a file who is
responsible for determining its licensing status, and per-source notices are
merely a convenience. Therefore it is simpler and more accurate for
each source to have a generic notice of the license name and references to
more detailed information on copyright holders and full license terms.
Our `Copyright.txt` file now contains a list of Contributors whose names
appeared source-level copyright notices. It also references version control
history for more precise information. Therefore we no longer need to spell
out the list of Contributors in each source file notice.
Replace CMake per-source copyright/license notice headers with a short
description of the license and links to `Copyright.txt` and online information
available from "https://cmake.org/licensing". The online URL also handles
cases of modules being copied out of our source into other projects, so we
can drop our notices about replacing links with full license text.
Run the `Utilities/Scripts/filter-notices.bash` script to perform the majority
of the replacements mechanically. Manually fix up shebang lines and trailing
newlines in a few files. Manually update the notices in a few files that the
script does not handle.
Populate standard include directories and link libraries for the
platform. Select the STL corresponding to CMAKE_ANDROID_STL_TYPE and
matching the current ABI and toolchain to be used. Refer to the NDK
sources/cxx-stl/*/Android.mk files for the needed file locations.
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.
Commonly used Android toolchain files that pre-date CMake upstream
support may need to be updated to work with our new functionality.
They typically set CMAKE_SYSTEM_VERSION to 1, so detect that and
skip our upstream Android settings. When such toolchain files are
updated to account for our upstream support, they can then set
CMAKE_SYSTEM_VERSION to a valid Android API and get new behavior.
Support for NVIDIA Nsight Tegra Visual Studio Edition was previously
implemented in the CMake VS IDE generators. Avoid interfering with
that functionality for now. Later we may try to integrate this.
Brad King