* [Debugger] Ensure that we use the correct paths in the mono mdb files to be able to step into the mono code.
Fixes bug 51530.
* Make the mdb paths to be correct in other platforms.
* Ensure mdb paths are also correct in XM.
Use @rpath instead of @executable_path in dylibs, since it allows us to be
more flexible when placing dylibs in the app.
In particular with this change it's trivial to put libmonosgen-2.0.dylib in
the container app, and reference it from extensions.
This is a series of fixes to the dynamic libraries we build / create to remove
any unnecessary bloat (unused architectures, bitcode).
A brand new watchOS app with no changes goes from 35MB to 11MB with these
fixes (with incremental builds disabled, the app size is 10MB).
--------------------------------------------------------------------------------
* [runtime] Split list of architectures into simulator and device-specific lists.
* [runtime] Build separate dylibs for device and simulator.
Build separate dylibs for device and simulator, since we already install these
into different locations.
This makes both the simulator and device builds slightly faster (since the
respective dylibs are smaller, and less data to copy around).
For watchOS apps, this saves ~430kb.
* [runtime] Strip bitcode from dylibs. Fixes#51352.
We know that dylibs will never be shipped to the App Store, so we'll never
need them to have bitcode.
So just strip the bitcode from all our dylibs, since this makes apps with
fastdev significantly smaller (and thus much faster to upload to watch
devices).
For watchOS apps this is a very significant improvement: a branch new watchOS
app without any changes goes from 35MB to 17MB.
https://bugzilla.xamarin.com/show_bug.cgi?id=51352
* [mtouch] Fix dylib compilation to not embed full bitcode.
Facts
=====
a. The output from the AOT compiler is an assembly (.s) file.
b. Clang's assembler does not support -fembed-bitcode-marker (only -fembed-
bitcode), so when we ask clang to -fembed-bitcode-marker, the assembler
receives a -fembed-bitcode argument.
c. This means that the assembled object file does not contain the
__LLVM/__bitcode and __LLVM/__cmdline sections (it does however contain an
__LLVM/__asm section).
d. The native linker will create a bitcode assembly section if none of the
object files passed to the linker contain a __LLVM/__bitcode section and
there's an __LLVM/__asm section present.
e. The end result is that when we build to a dylib, we end up (unexpectedly,
because we ask Clang to -fembed-bitcode-marker) including both armv7k and
bitcode in the dylib, thus bloating the dylib size significantly.
Solution
========
We manually add the __LLVM/__bitcode and __LLVM/__cmdline sections to the .s
file Mono's AOT compiler generated. This way the .o file will have the magic
sections, and the linker will not include bitcode (only the bitcode marker) in
the final library.
An empty watchOS extension with incremental builds is now 6MB smaller (down
to 11MB from 17MB).
* Pass -Wl,-no_weak_imports to the linker so that we don't accidentally use
symbols weakly. This would cause problems on older OSes where the symbol
isn't there, because our code is not prepared to deal with weakly linked
symbols.
* Manually disable fstatat and readlinkat (introduced with Xcode 7 in iOS 8 /
macOS 10.10), found by the above.
* Manually disable __thread support for a few targets, since mono's configure
script doesn't properly detect it's not supported.
* Manually disable clock_nanosleep, since mono's configure script doesn't
properly detect it's not supported.
* [builds] Don't install symlinks to iOS/Classic assemblies in the iOS/Unified profile.
* [fsharp] Don't install symlinks to iOS/Classic assemblies in the iOS/Unified profile.
The symlinks won't quite work once we remove the iOS/Classic assemblies.
* [C8] Bump to latest Mono 4.6.0 commit
Brings in the netstandard updates from https://github.com/mono/mono/pull/3394
We also had to add a new assembly System.IdentityModel.dll to the mobile profiles while doing that work.
* Add System.IdentityModel to Sdk assemblies
Fixes the following mtouch test failure:
```
Xamarin.Linker.SdkTest.iOS_Classic : BCL
Expected:
But was: < "System.IdentityModel" >
at NUnit.Framework.CollectionAssert.IsEmpty (IEnumerable collection, System.String message, System.Object[] args) <0x47bec88 + 0x00047> in :0
at NUnit.Framework.CollectionAssert.IsEmpty (IEnumerable collection, System.String message) <0x47bec58 + 0x0001f> in :0
at Xamarin.Linker.SdkTest.BCL (System.String path) <0x47bccf0 + 0x003f3> in :0
at Xamarin.Linker.SdkTest.iOS_Classic () <0x47bcc50 + 0x0001b> in :0
```
Brings in the netstandard updates from https://github.com/mono/mono/pull/3394
We also had to add a new assembly System.IdentityModel.dll to the mobile profiles while doing that work.
Since eaf2ceb532 there can be .dll.mdb files
for Facades as well which broke the Facades check.
The fix is to only include files ending in .dll and ignore the others.
Instead of having a symlink of the entire Facades directory for
Unified, we must now create a real directory and symlink each Facade
assembly, because there's one Facade assembly that can't be shared
between Unified and Classic (System.Drawing.Primitives.dll) because
it references monotouch.dll/Xamarin.iOS.dll.
If no sdk version (-sdk_version) is passed to the native
linker, it tries to infer the SDK version from the
path to the -syslibroot argument.
In our case we use a versioned path to Xcode, but a general
symlink without the SDK version:
/Applications/Xcode73.app/Contents/Developer/Platforms/AppleTVOS.platform/Developer/SDKs/AppleTVOS.sdk
which means ld picked up the Xcode version as the SDK version,
since that's the first number part of the path [1], so we'd
end up with libraries whose SDK version was 73.
So instead use an SDK path with the SDK version, so that ld
finds the SDK version instead of the Xcode version.
[1] 266f4401b9/src/ld/Options.cpp (L4005-L4020)https://bugzilla.xamarin.com/show_bug.cgi?id=41597
watchbcl uses mdb rebase from tools64, but adding a more "correct"
dependency when the mdb rebase occurs causes tools64 to be built
twice simultaneously (probably because we use submakes, so a different
make process also tries to build tools64).
So instead use a bigger hammer and just build tools64 completely
before building watchbcl.